diff --git a/05DWB1NzozM.txt b/05DWB1NzozM.txt new file mode 100644 index 0000000000000000000000000000000000000000..4f94b197c7d3bafd97cbf2e55d4217c9ce369b5d --- /dev/null +++ b/05DWB1NzozM.txt @@ -0,0 +1,827 @@ +align:start position:0% + +one of the most powerful properties of + + align:start position:0% +one of the most powerful properties of + + + align:start position:0% +one of the most powerful properties of +integer optimization is the ability to + + align:start position:0% +integer optimization is the ability to + + + align:start position:0% +integer optimization is the ability to +add what we call logical constraints + + align:start position:0% +add what we call logical constraints + + + align:start position:0% +add what we call logical constraints +these use binary variables to implement + + align:start position:0% +these use binary variables to implement + + + align:start position:0% +these use binary variables to implement +different restrictions let's look at a + + align:start position:0% +different restrictions let's look at a + + + align:start position:0% +different restrictions let's look at a +few examples suppose we want to add the + + align:start position:0% +few examples suppose we want to add the + + + align:start position:0% +few examples suppose we want to add the +constraint that a and B can't play in + + align:start position:0% +constraint that a and B can't play in + + + align:start position:0% +constraint that a and B can't play in +both weeks 3 & 4 we can do this by + + align:start position:0% +both weeks 3 & 4 we can do this by + + + align:start position:0% +both weeks 3 & 4 we can do this by +adding the constraint X a B 3 plus X a B + + align:start position:0% +adding the constraint X a B 3 plus X a B + + + align:start position:0% +adding the constraint X a B 3 plus X a B +4 less than or equal to 1 what our + + align:start position:0% +4 less than or equal to 1 what our + + + align:start position:0% +4 less than or equal to 1 what our +feasible values for these two variables + + align:start position:0% +feasible values for these two variables + + + align:start position:0% +feasible values for these two variables +given this constraint both variables can + + align:start position:0% +given this constraint both variables can + + + align:start position:0% +given this constraint both variables can +be 0 or 1 or the other can be 1 a + + align:start position:0% +be 0 or 1 or the other can be 1 a + + + align:start position:0% +be 0 or 1 or the other can be 1 a +solution with both variables equal to 1 + + align:start position:0% +solution with both variables equal to 1 + + + align:start position:0% +solution with both variables equal to 1 +would be infeasible so this constraint + + align:start position:0% +would be infeasible so this constraint + + + align:start position:0% +would be infeasible so this constraint +models the restriction that teams a and + + align:start position:0% +models the restriction that teams a and + + + align:start position:0% +models the restriction that teams a and +B can't play in both weeks 3 & 4 note + + align:start position:0% +B can't play in both weeks 3 & 4 note + + + align:start position:0% +B can't play in both weeks 3 & 4 note +that this only works because the + + align:start position:0% +that this only works because the + + + align:start position:0% +that this only works because the +variables only take values 0 or 1 let's + + align:start position:0% +variables only take values 0 or 1 let's + + + align:start position:0% +variables only take values 0 or 1 let's +look at another example suppose we want + + align:start position:0% +look at another example suppose we want + + + align:start position:0% +look at another example suppose we want +to add the restriction that if a and B + + align:start position:0% +to add the restriction that if a and B + + + align:start position:0% +to add the restriction that if a and B +play in week 4 then they must also play + + align:start position:0% +play in week 4 then they must also play + + + align:start position:0% +play in week 4 then they must also play +in week 2 we can do this by adding the + + align:start position:0% +in week 2 we can do this by adding the + + + align:start position:0% +in week 2 we can do this by adding the +constraint X a B 2 greater than or equal + + align:start position:0% +constraint X a B 2 greater than or equal + + + align:start position:0% +constraint X a B 2 greater than or equal +to X a B 4 let's consider feasible + + align:start position:0% +to X a B 4 let's consider feasible + + + align:start position:0% +to X a B 4 let's consider feasible +solutions to this constraint if X a B 4 + + align:start position:0% +solutions to this constraint if X a B 4 + + + align:start position:0% +solutions to this constraint if X a B 4 +equals 1 then X a B 2 must also equal 1 + + align:start position:0% +equals 1 then X a B 2 must also equal 1 + + + align:start position:0% +equals 1 then X a B 2 must also equal 1 +but if X a B 4 equals 0 then X a B 2 can + + align:start position:0% +but if X a B 4 equals 0 then X a B 2 can + + + align:start position:0% +but if X a B 4 equals 0 then X a B 2 can +be equal to either 0 or 1 + + align:start position:0% +be equal to either 0 or 1 + + + align:start position:0% +be equal to either 0 or 1 +so this constraint exactly models the + + align:start position:0% +so this constraint exactly models the + + + align:start position:0% +so this constraint exactly models the +restriction we wanted lastly suppose + + align:start position:0% +restriction we wanted lastly suppose + + + align:start position:0% +restriction we wanted lastly suppose +that Team C and D must play in week 1 or + + align:start position:0% +that Team C and D must play in week 1 or + + + align:start position:0% +that Team C and D must play in week 1 or +2 they can't play both games in weeks 3 + + align:start position:0% +2 they can't play both games in weeks 3 + + + align:start position:0% +2 they can't play both games in weeks 3 +& 4 we can model this constraint with X + + align:start position:0% +& 4 we can model this constraint with X + + + align:start position:0% +& 4 we can model this constraint with X +CD 1 plus X CD 2 greater than or equal + + align:start position:0% +CD 1 plus X CD 2 greater than or equal + + + align:start position:0% +CD 1 plus X CD 2 greater than or equal +to 1 feasible solutions are both + + align:start position:0% +to 1 feasible solutions are both + + + align:start position:0% +to 1 feasible solutions are both +variables equal to 1 or one variable + + align:start position:0% +variables equal to 1 or one variable + + + align:start position:0% +variables equal to 1 or one variable +equal to 1 both variables can't equal 0 + + align:start position:0% +equal to 1 both variables can't equal 0 + + + align:start position:0% +equal to 1 both variables can't equal 0 +these are just a few example + + align:start position:0% +these are just a few example + + + align:start position:0% +these are just a few example +of logical constraints that we can + + align:start position:0% +of logical constraints that we can + + + align:start position:0% +of logical constraints that we can +implement using binary variables let's + + align:start position:0% +implement using binary variables let's + + + align:start position:0% +implement using binary variables let's +go into libreoffice now and add these + + align:start position:0% +go into libreoffice now and add these + + + align:start position:0% +go into libreoffice now and add these +constraints to our model in our + + align:start position:0% +constraints to our model in our + + + align:start position:0% +constraints to our model in our +spreadsheet let's scroll down to the + + align:start position:0% +spreadsheet let's scroll down to the + + + align:start position:0% +spreadsheet let's scroll down to the +bottom of our constraints list we want + + align:start position:0% +bottom of our constraints list we want + + + align:start position:0% +bottom of our constraints list we want +to add in three new constraints the + + align:start position:0% +to add in three new constraints the + + + align:start position:0% +to add in three new constraints the +first is that teams a and B can't play + + align:start position:0% +first is that teams a and B can't play + + + align:start position:0% +first is that teams a and B can't play +in both weeks three and four the second + + align:start position:0% +in both weeks three and four the second + + + align:start position:0% +in both weeks three and four the second +is that if teams a and B play in week + + align:start position:0% +is that if teams a and B play in week + + + align:start position:0% +is that if teams a and B play in week +four then they have to play a week two + + align:start position:0% +four then they have to play a week two + + + align:start position:0% +four then they have to play a week two +and the third is that team C and D have + + align:start position:0% +and the third is that team C and D have + + + align:start position:0% +and the third is that team C and D have +to play in weeks one and/or two so to + + align:start position:0% +to play in weeks one and/or two so to + + + align:start position:0% +to play in weeks one and/or two so to +add the first constraint our left-hand + + align:start position:0% +add the first constraint our left-hand + + + align:start position:0% +add the first constraint our left-hand +side should be equal to the sum of the + + align:start position:0% +side should be equal to the sum of the + + + align:start position:0% +side should be equal to the sum of the +variables for a and B in weeks three and + + align:start position:0% +variables for a and B in weeks three and + + + align:start position:0% +variables for a and B in weeks three and +four our sign is less than or equal to + + align:start position:0% +four our sign is less than or equal to + + + align:start position:0% +four our sign is less than or equal to +and our right-hand side is 1 our second + + align:start position:0% +and our right-hand side is 1 our second + + + align:start position:0% +and our right-hand side is 1 our second +constraint the left-hand side is equal + + align:start position:0% +constraint the left-hand side is equal + + + align:start position:0% +constraint the left-hand side is equal +to the decision variable for teams a and + + align:start position:0% +to the decision variable for teams a and + + + align:start position:0% +to the decision variable for teams a and +B in week 2 + + align:start position:0% +B in week 2 + + + align:start position:0% +B in week 2 +the sign is greater than or equal to and + + align:start position:0% +the sign is greater than or equal to and + + + align:start position:0% +the sign is greater than or equal to and +the right-hand side is equal to the + + align:start position:0% +the right-hand side is equal to the + + + align:start position:0% +the right-hand side is equal to the +decision variable for teams a and B in + + align:start position:0% +decision variable for teams a and B in + + + align:start position:0% +decision variable for teams a and B in +week 4 for our third constraint the + + align:start position:0% +week 4 for our third constraint the + + + align:start position:0% +week 4 for our third constraint the +left-hand side is equal to the decision + + align:start position:0% +left-hand side is equal to the decision + + + align:start position:0% +left-hand side is equal to the decision +variables for Team C and D in weeks one + + align:start position:0% +variables for Team C and D in weeks one + + + align:start position:0% +variables for Team C and D in weeks one +and two the sine is greater than or + + align:start position:0% +and two the sine is greater than or + + + align:start position:0% +and two the sine is greater than or +equal to and the right-hand side is one + + align:start position:0% + + + + align:start position:0% + +we can see here that our current optimal + + align:start position:0% +we can see here that our current optimal + + + align:start position:0% +we can see here that our current optimal +solution violates every single one of + + align:start position:0% +solution violates every single one of + + + align:start position:0% +solution violates every single one of +these constraints so let's go ahead and + + align:start position:0% +these constraints so let's go ahead and + + + align:start position:0% +these constraints so let's go ahead and +Reese all var model to get a new + + align:start position:0% +Reese all var model to get a new + + + align:start position:0% +Reese all var model to get a new +solution so go to the Tools menu and + + align:start position:0% +solution so go to the Tools menu and + + + align:start position:0% +solution so go to the Tools menu and +select solver now let's add in our new + + align:start position:0% +select solver now let's add in our new + + + align:start position:0% +select solver now let's add in our new +constraints so in the third cell + + align:start position:0% +constraints so in the third cell + + + align:start position:0% +constraints so in the third cell +reference box go in and select the + + align:start position:0% +reference box go in and select the + + + align:start position:0% +reference box go in and select the +left-hand side for the first constraint + + align:start position:0% +left-hand side for the first constraint + + + align:start position:0% +left-hand side for the first constraint +make sure the operator is less than or + + align:start position:0% +make sure the operator is less than or + + + align:start position:0% +make sure the operator is less than or +equal to and select the right-hand side + + align:start position:0% +equal to and select the right-hand side + + + align:start position:0% +equal to and select the right-hand side +for the value then in the fourth cell + + align:start position:0% +for the value then in the fourth cell + + + align:start position:0% +for the value then in the fourth cell +reference box select both of the + + align:start position:0% +reference box select both of the + + + align:start position:0% +reference box select both of the +left-hand sides for the + + align:start position:0% +left-hand sides for the + + + align:start position:0% +left-hand sides for the +other constraints because they're both + + align:start position:0% +other constraints because they're both + + + align:start position:0% +other constraints because they're both +greater than or equal to constraints + + align:start position:0% +greater than or equal to constraints + + + align:start position:0% +greater than or equal to constraints +change the operator to greater than or + + align:start position:0% +change the operator to greater than or + + + align:start position:0% +change the operator to greater than or +equal to and for the value select the + + align:start position:0% +equal to and for the value select the + + + align:start position:0% +equal to and for the value select the +two right-hand sides and go ahead and + + align:start position:0% +two right-hand sides and go ahead and + + + align:start position:0% +two right-hand sides and go ahead and +click solve the solving result says + + align:start position:0% +click solve the solving result says + + + align:start position:0% +click solve the solving result says +solving successfully finished result 20 + + align:start position:0% +solving successfully finished result 20 + + + align:start position:0% +solving successfully finished result 20 +select keep result let's look at our new + + align:start position:0% +select keep result let's look at our new + + + align:start position:0% +select keep result let's look at our new +solution the objective value is now 20 + + align:start position:0% +solution the objective value is now 20 + + + align:start position:0% +solution the objective value is now 20 +which is less than it was before but now + + align:start position:0% +which is less than it was before but now + + + align:start position:0% +which is less than it was before but now +we have teams a and B plane in weeks two + + align:start position:0% +we have teams a and B plane in weeks two + + + align:start position:0% +we have teams a and B plane in weeks two +and four and team C and D plane in weeks + + align:start position:0% +and four and team C and D plane in weeks + + + align:start position:0% +and four and team C and D plane in weeks +two and four so depending on your + + align:start position:0% +two and four so depending on your + + + align:start position:0% +two and four so depending on your +preferences as a decision maker you + + align:start position:0% +preferences as a decision maker you + + + align:start position:0% +preferences as a decision maker you +might prefer the previous solution which + + align:start position:0% +might prefer the previous solution which + + + align:start position:0% +might prefer the previous solution which +had a slightly higher objective or this + + align:start position:0% +had a slightly higher objective or this + + + align:start position:0% +had a slightly higher objective or this +solution which is a little more balanced + + align:start position:0% +solution which is a little more balanced + + + align:start position:0% +solution which is a little more balanced +in the next video we'll discuss how + + align:start position:0% +in the next video we'll discuss how + + + align:start position:0% +in the next video we'll discuss how +additional constraints often make the + + align:start position:0% +additional constraints often make the + + + align:start position:0% +additional constraints often make the +problems harder to solve and how large + + align:start position:0% +problems harder to solve and how large + + + align:start position:0% +problems harder to solve and how large +integer optimization problems are solved + + align:start position:0% +integer optimization problems are solved + + + align:start position:0% +integer optimization problems are solved +in practice \ No newline at end of file diff --git a/0egP7_kq23E.txt b/0egP7_kq23E.txt new file mode 100644 index 0000000000000000000000000000000000000000..56762eff59e09ab962792e660e88bfdf7151314b --- /dev/null +++ b/0egP7_kq23E.txt @@ -0,0 +1,8376 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +to view additional materials from + + align:start position:0% +to view additional materials from + + + align:start position:0% +to view additional materials from +hundreds of MIT courses visit MIT open + + align:start position:0% +hundreds of MIT courses visit MIT open + + + align:start position:0% +hundreds of MIT courses visit MIT open +courseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu so this is a review session + + align:start position:0% +ocw.mit.edu so this is a review session + + + align:start position:0% +ocw.mit.edu so this is a review session +number five I guess it is uh and it + + align:start position:0% +number five I guess it is uh and it + + + align:start position:0% +number five I guess it is uh and it +comes uh before an exam next Tuesday and + + align:start position:0% +comes uh before an exam next Tuesday and + + + align:start position:0% +comes uh before an exam next Tuesday and +actually there'll be a further review + + align:start position:0% +actually there'll be a further review + + + align:start position:0% +actually there'll be a further review +session number six uh on Monday uh right + + align:start position:0% +session number six uh on Monday uh right + + + align:start position:0% +session number six uh on Monday uh right +before the exam so + + align:start position:0% +before the exam so + + + align:start position:0% +before the exam so +uh so maybe today we would there's a + + align:start position:0% +uh so maybe today we would there's a + + + align:start position:0% +uh so maybe today we would there's a +homework uh problem set on sections on + + align:start position:0% +homework uh problem set on sections on + + + align:start position:0% +homework uh problem set on sections on +chapter two SEC the uh the mostly the + + align:start position:0% +chapter two SEC the uh the mostly the + + + align:start position:0% +chapter two SEC the uh the mostly the +oscillating masses and springs and the + + align:start position:0% +oscillating masses and springs and the + + + align:start position:0% +oscillating masses and springs and the +uh today's uh lecture that you see + + align:start position:0% +uh today's uh lecture that you see + + + align:start position:0% +uh today's uh lecture that you see +traces of of U + + align:start position:0% +traces of of U + + + align:start position:0% +traces of of U +networks + + align:start position:0% +networks + + + align:start position:0% +networks +um and masses and springs also the + + align:start position:0% +um and masses and springs also the + + + align:start position:0% +um and masses and springs also the +static case so I I'm open as always to + + align:start position:0% +static case so I I'm open as always to + + + align:start position:0% +static case so I I'm open as always to +questions yes please thank you 2.2 + + align:start position:0% +questions yes please thank you 2.2 + + + align:start position:0% +questions yes please thank you 2.2 +number 2.2 number + + align:start position:0% + + + + align:start position:0% + +six okay yeah so this is uh and of + + align:start position:0% +six okay yeah so this is uh and of + + + align:start position:0% +six okay yeah so this is uh and of +course you understand so I'm happy + + align:start position:0% +course you understand so I'm happy + + + align:start position:0% +course you understand so I'm happy +that's a good question to discuss and + + align:start position:0% +that's a good question to discuss and + + + align:start position:0% +that's a good question to discuss and +and maybe number seven people will have + + align:start position:0% +and maybe number seven people will have + + + align:start position:0% +and maybe number seven people will have +some thing to say about uh good uh yeah + + align:start position:0% +some thing to say about uh good uh yeah + + + align:start position:0% +some thing to say about uh good uh yeah +so that that's just fine so so let me + + align:start position:0% +so that that's just fine so so let me + + + align:start position:0% +so that that's just fine so so let me +start right in on + + align:start position:0% +start right in on + + + align:start position:0% +start right in on +those so number six is the fact + + align:start position:0% +those so number six is the fact + + + align:start position:0% +those so number six is the fact +uh I mean everybody understands that + + align:start position:0% +uh I mean everybody understands that + + + align:start position:0% +uh I mean everybody understands that +when energy is conserved that's an + + align:start position:0% +when energy is conserved that's an + + + align:start position:0% +when energy is conserved that's an +important + + align:start position:0% +important + + + align:start position:0% +important +thing and the so the question is first + + align:start position:0% +thing and the so the question is first + + + align:start position:0% +thing and the so the question is first +first when is energy conserved in the + + align:start position:0% +first when is energy conserved in the + + + align:start position:0% +first when is energy conserved in the +differential equation in the equation + + align:start position:0% +differential equation in the equation + + + align:start position:0% +differential equation in the equation +we're trying to solve and if it is then + + align:start position:0% +we're trying to solve and if it is then + + + align:start position:0% +we're trying to solve and if it is then +we want to know we would like to choose + + align:start position:0% +we want to know we would like to choose + + + align:start position:0% +we want to know we would like to choose +difference methods that also conserve + + align:start position:0% +difference methods that also conserve + + + align:start position:0% +difference methods that also conserve +energy uh that may they may not be + + align:start position:0% +energy uh that may they may not be + + + align:start position:0% +energy uh that may they may not be +exactly right they may not be exactly at + + align:start position:0% +exactly right they may not be exactly at + + + align:start position:0% +exactly right they may not be exactly at +the right point on this circle if we're + + align:start position:0% +the right point on this circle if we're + + + align:start position:0% +the right point on this circle if we're +in that model problem but still on the + + align:start position:0% +in that model problem but still on the + + + align:start position:0% +in that model problem but still on the +circle so and the point is that the + + align:start position:0% +circle so and the point is that the + + + align:start position:0% +circle so and the point is that the +trapezoidal method does stay on the + + align:start position:0% +trapezoidal method does stay on the + + + align:start position:0% +trapezoidal method does stay on the +circle and of course the differential + + align:start position:0% +circle and of course the differential + + + align:start position:0% +circle and of course the differential +equation stays on the circle can I uh so + + align:start position:0% +equation stays on the circle can I uh so + + + align:start position:0% +equation stays on the circle can I uh so +and I tried I put quite a bit into this + + align:start position:0% +and I tried I put quite a bit into this + + + align:start position:0% +and I tried I put quite a bit into this +problem six so this is + + align:start position:0% +problem six so this is + + + align:start position:0% +problem six so this is +2.2.6 and + + align:start position:0% +2.2.6 and + + + align:start position:0% +2.2.6 and +uh and let me try to say say something + + align:start position:0% +uh and let me try to say say something + + + align:start position:0% +uh and let me try to say say something +about that okay so first of all it + + align:start position:0% +about that okay so first of all it + + + align:start position:0% +about that okay so first of all it +there's the continuous problem DT equal + + align:start position:0% +there's the continuous problem DT equal + + + align:start position:0% +there's the continuous problem DT equal +Au when does does that conserve energy + + align:start position:0% +Au when does does that conserve energy + + + align:start position:0% +Au when does does that conserve energy +and then there's the discret problem + + align:start position:0% +and then there's the discret problem + + + align:start position:0% +and then there's the discret problem +which uh we know that uh Oiler doesn't + + align:start position:0% +which uh we know that uh Oiler doesn't + + + align:start position:0% +which uh we know that uh Oiler doesn't +conserve energy because we just we've + + align:start position:0% +conserve energy because we just we've + + + align:start position:0% +conserve energy because we just we've +seen it the the computer shows you right + + align:start position:0% +seen it the the computer shows you right + + + align:start position:0% +seen it the the computer shows you right +away it goes it it spirals out from the + + align:start position:0% +away it goes it it spirals out from the + + + align:start position:0% +away it goes it it spirals out from the +circle it spirals in for forward and + + align:start position:0% +circle it spirals in for forward and + + + align:start position:0% +circle it spirals in for forward and +backward Oiler but trapezoidal method is + + align:start position:0% +backward Oiler but trapezoidal method is + + + align:start position:0% +backward Oiler but trapezoidal method is +that the one that turns out to be well + + align:start position:0% +that the one that turns out to be well + + + align:start position:0% +that the one that turns out to be well +okay so it says it refers to equation 24 + + align:start position:0% +okay so it says it refers to equation 24 + + + align:start position:0% +okay so it says it refers to equation 24 +as the trapezoidal method and let me try + + align:start position:0% +as the trapezoidal method and let me try + + + align:start position:0% +as the trapezoidal method and let me try +to follow that notation yeah uh so this + + align:start position:0% +to follow that notation yeah uh so this + + + align:start position:0% +to follow that notation yeah uh so this +is the trapezoidal method + + align:start position:0% + + + + align:start position:0% + +is is uh this one did we get music there + + align:start position:0% +is is uh this one did we get music there + + + align:start position:0% +is is uh this one did we get music there +for the trapezoidal method okay n + 1 + + align:start position:0% +for the trapezoidal method okay n + 1 + + + align:start position:0% +for the trapezoidal method okay n + 1 +equal I + a Delta t/ 2 unu N okay + + align:start position:0% + + + + align:start position:0% + +right okay so that uh and actually + + align:start position:0% +right okay so that uh and actually + + + align:start position:0% +right okay so that uh and actually +problem seven that you may be want to + + align:start position:0% +problem seven that you may be want to + + + align:start position:0% +problem seven that you may be want to +discuss too is the question of how + + align:start position:0% +discuss too is the question of how + + + align:start position:0% +discuss too is the question of how +accurate this is compared to the + + align:start position:0% +accurate this is compared to the + + + align:start position:0% +accurate this is compared to the +differential equation everybody should + + align:start position:0% +differential equation everybody should + + + align:start position:0% +differential equation everybody should +see that this really came + + align:start position:0% +see that this really came + + + align:start position:0% +see that this really came +from the original way to look at this + + align:start position:0% +from the original way to look at this + + + align:start position:0% +from the original way to look at this +was UN n + 1us un n/ delta T that + + align:start position:0% +was UN n + 1us un n/ delta T that + + + align:start position:0% +was UN n + 1us un n/ delta T that +approximated the D itive equals a and + + align:start position:0% +approximated the D itive equals a and + + + align:start position:0% +approximated the D itive equals a and +then I'm taking half of I'm taking half + + align:start position:0% +then I'm taking half of I'm taking half + + + align:start position:0% +then I'm taking half of I'm taking half +at U and at the new time and half at the + + align:start position:0% +at U and at the new time and half at the + + + align:start position:0% +at U and at the new time and half at the +old time so it's got that + + align:start position:0% +old time so it's got that + + + align:start position:0% +old time so it's got that +centering that that we suspect will give + + align:start position:0% +centering that that we suspect will give + + + align:start position:0% +centering that that we suspect will give +us a little extra accuracy okay so so + + align:start position:0% +us a little extra accuracy okay so so + + + align:start position:0% +us a little extra accuracy okay so so +two questions then one was the + + align:start position:0% +two questions then one was the + + + align:start position:0% +two questions then one was the +stability so so question problem six was + + align:start position:0% +stability so so question problem six was + + + align:start position:0% +stability so so question problem six was +the energy conserved + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +problem 2.2.7 if I anticipated is the + + align:start position:0% +problem 2.2.7 if I anticipated is the + + + align:start position:0% +problem 2.2.7 if I anticipated is the +order of + + align:start position:0% +order of + + + align:start position:0% +order of +accuracy so these are both + + align:start position:0% +accuracy so these are both + + + align:start position:0% +accuracy so these are both +topics that uh are extremely important + + align:start position:0% +topics that uh are extremely important + + + align:start position:0% +topics that uh are extremely important +in choosing a difference method we're + + align:start position:0% +in choosing a difference method we're + + + align:start position:0% +in choosing a difference method we're +very happy to know that this conser well + + align:start position:0% +very happy to know that this conser well + + + align:start position:0% +very happy to know that this conser well +we would like to know first when does + + align:start position:0% +we would like to know first when does + + + align:start position:0% +we would like to know first when does +when is energy conserved there in the + + align:start position:0% +when is energy conserved there in the + + + align:start position:0% +when is energy conserved there in the +what differential equation have + + align:start position:0% +what differential equation have + + + align:start position:0% +what differential equation have +conserved energy physically we kind of + + align:start position:0% +conserved energy physically we kind of + + + align:start position:0% +conserved energy physically we kind of +can see them coming you know if the + + align:start position:0% +can see them coming you know if the + + + align:start position:0% +can see them coming you know if the +physical uh universe is not being uh you + + align:start position:0% +physical uh universe is not being uh you + + + align:start position:0% +physical uh universe is not being uh you +know it's somehow lot lots of physical + + align:start position:0% +know it's somehow lot lots of physical + + + align:start position:0% +know it's somehow lot lots of physical +problems we see those masses and springs + + align:start position:0% +problems we see those masses and springs + + + align:start position:0% +problems we see those masses and springs +oscillating and and we say Okay + + align:start position:0% +oscillating and and we say Okay + + + align:start position:0% +oscillating and and we say Okay +nothing's coming in from outside how + + align:start position:0% +nothing's coming in from outside how + + + align:start position:0% +nothing's coming in from outside how +could energy there would be the sum of + + align:start position:0% +could energy there would be the sum of + + + align:start position:0% +could energy there would be the sum of +the kinetic energy of the + + align:start position:0% +the kinetic energy of the + + + align:start position:0% +the kinetic energy of the +masses and the potential energy in the + + align:start position:0% +masses and the potential energy in the + + + align:start position:0% +masses and the potential energy in the +springs so so energy passes + + align:start position:0% +springs so so energy passes + + + align:start position:0% +springs so so energy passes +between kinetic when the mass is zooming + + align:start position:0% +between kinetic when the mass is zooming + + + align:start position:0% +between kinetic when the mass is zooming +past equilibrium + + align:start position:0% +past equilibrium + + + align:start position:0% +past equilibrium +and and potential energy when the mass + + align:start position:0% +and and potential energy when the mass + + + align:start position:0% +and and potential energy when the mass +is stretching the spring so that we've + + align:start position:0% +is stretching the spring so that we've + + + align:start position:0% +is stretching the spring so that we've +got two cases so and we would hope and + + align:start position:0% +got two cases so and we would hope and + + + align:start position:0% +got two cases so and we would hope and +this trapezoidal method comes through + + align:start position:0% +this trapezoidal method comes through + + + align:start position:0% +this trapezoidal method comes through +that energy is conserved so can I just + + align:start position:0% +that energy is conserved so can I just + + + align:start position:0% +that energy is conserved so can I just +begin with this + + align:start position:0% +begin with this + + + align:start position:0% +begin with this +one maybe I always ought to say cuz you + + align:start position:0% +one maybe I always ought to say cuz you + + + align:start position:0% +one maybe I always ought to say cuz you +guys are also thinking about the + + align:start position:0% +guys are also thinking about the + + + align:start position:0% +guys are also thinking about the +quiz and + + align:start position:0% +quiz and + + + align:start position:0% +quiz and +uh + + align:start position:0% +uh + + + align:start position:0% +uh +um so this this for example this + + align:start position:0% +um so this this for example this + + + align:start position:0% +um so this this for example this +question about how to find the order of + + align:start position:0% +question about how to find the order of + + + align:start position:0% +question about how to find the order of +accuracy that's uh I I'll speak about + + align:start position:0% +accuracy that's uh I I'll speak about + + + align:start position:0% +accuracy that's uh I I'll speak about +that but let me just say I I that's not + + align:start position:0% +that but let me just say I I that's not + + + align:start position:0% +that but let me just say I I that's not +something that we've done in enough + + align:start position:0% +something that we've done in enough + + + align:start position:0% +something that we've done in enough +detail that I would expect you to be + + align:start position:0% +detail that I would expect you to be + + + align:start position:0% +detail that I would expect you to be +quick on the quiz and just be able to do + + align:start position:0% +quick on the quiz and just be able to do + + + align:start position:0% +quick on the quiz and just be able to do +it out uh you know I I'll try to + + align:start position:0% +it out uh you know I I'll try to + + + align:start position:0% +it out uh you know I I'll try to +choose ex questions on the exam that you + + align:start position:0% +choose ex questions on the exam that you + + + align:start position:0% +choose ex questions on the exam that you +really have had more practice with but + + align:start position:0% +really have had more practice with but + + + align:start position:0% +really have had more practice with but +this is certainly important so it's was + + align:start position:0% +this is certainly important so it's was + + + align:start position:0% +this is certainly important so it's was +definitely right to put on the homework + + align:start position:0% +definitely right to put on the homework + + + align:start position:0% +definitely right to put on the homework +and this is important okay uh so let me + + align:start position:0% +and this is important okay uh so let me + + + align:start position:0% +and this is important okay uh so let me +let me tackle this + + align:start position:0% +let me tackle this + + + align:start position:0% +let me tackle this +one first the differential equation so + + align:start position:0% +one first the differential equation so + + + align:start position:0% +one first the differential equation so +by energy here I'm meaning just the + + align:start position:0% +by energy here I'm meaning just the + + + align:start position:0% +by energy here I'm meaning just the +length of U squared + + align:start position:0% +length of U squared + + + align:start position:0% +length of U squared +so let me uh so now I'm looking at + + align:start position:0% +so let me uh so now I'm looking at + + + align:start position:0% +so let me uh so now I'm looking at +energy conserved okay so I'm hoping + + align:start position:0% +energy conserved okay so I'm hoping + + + align:start position:0% +energy conserved okay so I'm hoping +energy conserved would mean that the + + align:start position:0% +energy conserved would mean that the + + + align:start position:0% +energy conserved would mean that the +derivative of + + align:start position:0% +derivative of + + + align:start position:0% +derivative of +u^2 was Zero that that's what energy + + align:start position:0% +u^2 was Zero that that's what energy + + + align:start position:0% +u^2 was Zero that that's what energy +conserving energy would mean and my + + align:start position:0% +conserving energy would mean and my + + + align:start position:0% +conserving energy would mean and my +question is which differential equations + + align:start position:0% +question is which differential equations + + + align:start position:0% +question is which differential equations +what what's the condition on a in other + + align:start position:0% +what what's the condition on a in other + + + align:start position:0% +what what's the condition on a in other +words that that I should what how would + + align:start position:0% +words that that I should what how would + + + align:start position:0% +words that that I should what how would +I recognize from this m Matrix a that I + + align:start position:0% +I recognize from this m Matrix a that I + + + align:start position:0% +I recognize from this m Matrix a that I +have this interesting property okay so + + align:start position:0% +have this interesting property okay so + + + align:start position:0% +have this interesting property okay so +let me just show you what I would do + + align:start position:0% +let me just show you what I would do + + + align:start position:0% +let me just show you what I would do +okay another way to write u^2 is U + + align:start position:0% +okay another way to write u^2 is U + + + align:start position:0% +okay another way to write u^2 is U +transpose U these These are vectors of + + align:start position:0% +transpose U these These are vectors of + + + align:start position:0% +transpose U these These are vectors of +course okay okay so what's the + + align:start position:0% +course okay okay so what's the + + + align:start position:0% +course okay okay so what's the +derivative of U transpose U see I've got + + align:start position:0% +derivative of U transpose U see I've got + + + align:start position:0% +derivative of U transpose U see I've got +my equation is telling me what the + + align:start position:0% +my equation is telling me what the + + + align:start position:0% +my equation is telling me what the +derivative of U is here I've got the + + align:start position:0% +derivative of U is here I've got the + + + align:start position:0% +derivative of U is here I've got the +thing squared okay + + align:start position:0% +thing squared okay + + + align:start position:0% +thing squared okay +it's I mean I have a product here right + + align:start position:0% +it's I mean I have a product here right + + + align:start position:0% +it's I mean I have a product here right +I've Ed times use so I'm going to use + + align:start position:0% +I've Ed times use so I'm going to use + + + align:start position:0% +I've Ed times use so I'm going to use +this the standard they happen to be + + align:start position:0% +this the standard they happen to be + + + align:start position:0% +this the standard they happen to be +vectors so I'd have if I want to use + + align:start position:0% +vectors so I'd have if I want to use + + + align:start position:0% +vectors so I'd have if I want to use +like freshman calculus I'd have to get + + align:start position:0% +like freshman calculus I'd have to get + + + align:start position:0% +like freshman calculus I'd have to get +down to the scaler to get down to the + + align:start position:0% +down to the scaler to get down to the + + + align:start position:0% +down to the scaler to get down to the +numbers but I absolutely could do that + + align:start position:0% +numbers but I absolutely could do that + + + align:start position:0% +numbers but I absolutely could do that +and just follow them along component by + + align:start position:0% +and just follow them along component by + + + align:start position:0% +and just follow them along component by +component or I could try to do it a v + + align:start position:0% +component or I could try to do it a v + + + align:start position:0% +component or I could try to do it a v +the whole column at a time and and let + + align:start position:0% +the whole column at a time and and let + + + align:start position:0% +the whole column at a time and and let +me try that that it's going to be the + + align:start position:0% +me try that that it's going to be the + + + align:start position:0% +me try that that it's going to be the +product rule right it's some in some + + align:start position:0% +product rule right it's some in some + + + align:start position:0% +product rule right it's some in some +form that I'll have this guy times the + + align:start position:0% +form that I'll have this guy times the + + + align:start position:0% +form that I'll have this guy times the +derivative of + + align:start position:0% +derivative of + + + align:start position:0% +derivative of +this plus the derivative I'll keep them + + align:start position:0% +this plus the derivative I'll keep them + + + align:start position:0% +this plus the derivative I'll keep them +in order the derivative of this + + align:start position:0% +in order the derivative of this + + + align:start position:0% +in order the derivative of this +thing times this guy right that that + + align:start position:0% +thing times this guy right that that + + + align:start position:0% +thing times this guy right that that +should be that's the product rule okay + + align:start position:0% +should be that's the product rule okay + + + align:start position:0% +should be that's the product rule okay +now what do I know here I know that the + + align:start position:0% +now what do I know here I know that the + + + align:start position:0% +now what do I know here I know that the +dudt is au right so this is U transpose + + align:start position:0% + + + + align:start position:0% + +Au and I + + align:start position:0% +Au and I + + + align:start position:0% +Au and I +know du is that DT meant to be + + align:start position:0% +know du is that DT meant to be + + + align:start position:0% +know du is that DT meant to be +DT so what's so du DT is au again look + + align:start position:0% +DT so what's so du DT is au again look + + + align:start position:0% +DT so what's so du DT is au again look +it's this isn't difficult it's + + align:start position:0% +it's this isn't difficult it's + + + align:start position:0% +it's this isn't difficult it's +Au transpose U and the question is when + + align:start position:0% +Au transpose U and the question is when + + + align:start position:0% +Au transpose U and the question is when +is this zero okay so U so this was those + + align:start position:0% +is this zero okay so U so this was those + + + align:start position:0% +is this zero okay so U so this was those +were the two terms from the product rule + + align:start position:0% +were the two terms from the product rule + + + align:start position:0% +were the two terms from the product rule +and notice they're not exactly the same + + align:start position:0% +and notice they're not exactly the same + + + align:start position:0% +and notice they're not exactly the same +this is U transpose a u and what's this + + align:start position:0% +this is U transpose a u and what's this + + + align:start position:0% +this is U transpose a u and what's this +guy you transpose a transpose U so if I + + align:start position:0% +guy you transpose a transpose U so if I + + + align:start position:0% +guy you transpose a transpose U so if I +put them together I have U transpose + + align:start position:0% +put them together I have U transpose + + + align:start position:0% +put them together I have U transpose +times the A and the a + + align:start position:0% +times the A and the a + + + align:start position:0% +times the A and the a +transpose times U and I'm want I'm + + align:start position:0% +transpose times U and I'm want I'm + + + align:start position:0% +transpose times U and I'm want I'm +hoping that this will be zero for all + + align:start position:0% +hoping that this will be zero for all + + + align:start position:0% +hoping that this will be zero for all +these all the solutions that I've come + + align:start position:0% +these all the solutions that I've come + + + align:start position:0% +these all the solutions that I've come +up with so the condition is simply + + align:start position:0% +up with so the condition is simply + + + align:start position:0% +up with so the condition is simply +that that a plus a we want that to be + + align:start position:0% +that that a plus a we want that to be + + + align:start position:0% +that that a plus a we want that to be +the zero Matrix a plus a transpose if + + align:start position:0% +the zero Matrix a plus a transpose if + + + align:start position:0% +the zero Matrix a plus a transpose if +that's if if in other words if a + + align:start position:0% +that's if if in other words if a + + + align:start position:0% +that's if if in other words if a +transpose is minus a that that's the + + align:start position:0% +transpose is minus a that that's the + + + align:start position:0% +transpose is minus a that that's the +that's the good one if a transposes + + align:start position:0% +that's the good one if a transposes + + + align:start position:0% +that's the good one if a transposes +minus a this is zero that's zero that's + + align:start position:0% +minus a this is zero that's zero that's + + + align:start position:0% +minus a this is zero that's zero that's +zero that's zero energy is conserved so + + align:start position:0% +zero that's zero energy is conserved so + + + align:start position:0% +zero that's zero energy is conserved so +the energy is conserved when a transpose + + align:start position:0% +the energy is conserved when a transpose + + + align:start position:0% +the energy is conserved when a transpose +is minus + + align:start position:0% +is minus + + + align:start position:0% +is minus +a it's for the anti-symmetric A's that + + align:start position:0% +a it's for the anti-symmetric A's that + + + align:start position:0% +a it's for the anti-symmetric A's that +energy conserved and of course this all + + align:start position:0% +energy conserved and of course this all + + + align:start position:0% +energy conserved and of course this all +makes sense + + align:start position:0% +makes sense + + + align:start position:0% +makes sense +uh what are the special solutions to + + align:start position:0% +uh what are the special solutions to + + + align:start position:0% +uh what are the special solutions to +that differential equation the special + + align:start position:0% +that differential equation the special + + + align:start position:0% +that differential equation the special +solutions to this equation are e to the + + align:start position:0% +solutions to this equation are e to the + + + align:start position:0% +solutions to this equation are e to the +just just this + + align:start position:0% +just just this + + + align:start position:0% +just just this +is connecting now with with things that + + align:start position:0% +is connecting now with with things that + + + align:start position:0% +is connecting now with with things that +really are basic the special Solutions + + align:start position:0% +really are basic the special Solutions + + + align:start position:0% +really are basic the special Solutions +the the Pure igen Solutions the one the + + align:start position:0% +the the Pure igen Solutions the one the + + + align:start position:0% +the the Pure igen Solutions the one the +ones that follow their own paths are the + + align:start position:0% +ones that follow their own paths are the + + + align:start position:0% +ones that follow their own paths are the +e to the Lambda T X's right where X is + + align:start position:0% +e to the Lambda T X's right where X is + + + align:start position:0% +e to the Lambda T X's right where X is +an IG Vector of a and Lambda is an igen + + align:start position:0% +an IG Vector of a and Lambda is an igen + + + align:start position:0% +an IG Vector of a and Lambda is an igen +value those are the guys and we expect + + align:start position:0% +value those are the guys and we expect + + + align:start position:0% +value those are the guys and we expect +to have n of them and we expect a + + align:start position:0% +to have n of them and we expect a + + + align:start position:0% +to have n of them and we expect a +combination of those to give us the + + align:start position:0% +combination of those to give us the + + + align:start position:0% +combination of those to give us the +general solution and to match the + + align:start position:0% +general solution and to match the + + + align:start position:0% +general solution and to match the +boundary condition so these are the + + align:start position:0% +boundary condition so these are the + + + align:start position:0% +boundary condition so these are the +these these n of these guys with n + + align:start position:0% +these these n of these guys with n + + + align:start position:0% +these these n of these guys with n +different IG vectors and their igen + + align:start position:0% +different IG vectors and their igen + + + align:start position:0% +different IG vectors and their igen +values are the heart of + + align:start position:0% +values are the heart of + + + align:start position:0% +values are the heart of +uh problems like this and and of course + + align:start position:0% +uh problems like this and and of course + + + align:start position:0% +uh problems like this and and of course +that's um you know the the additional + + align:start position:0% +that's um you know the the additional + + + align:start position:0% +that's um you know the the additional +homework problem that I that wasn't in + + align:start position:0% +homework problem that I that wasn't in + + + align:start position:0% +homework problem that I that wasn't in +the book but I added as an additional + + align:start position:0% +the book but I added as an additional + + + align:start position:0% +the book but I added as an additional +problem was exactly that to get you to + + align:start position:0% +problem was exactly that to get you to + + + align:start position:0% +problem was exactly that to get you to +practice with these Z vectors and I + + align:start position:0% +practice with these Z vectors and I + + + align:start position:0% +practice with these Z vectors and I +values Okay now what's the deal I want + + align:start position:0% +values Okay now what's the deal I want + + + align:start position:0% +values Okay now what's the deal I want +to connect this energy conserving with + + align:start position:0% +to connect this energy conserving with + + + align:start position:0% +to connect this energy conserving with +with this picture of solutions when + + align:start position:0% +with this picture of solutions when + + + align:start position:0% +with this picture of solutions when +would this keep the same energy when + + align:start position:0% +would this keep the same energy when + + + align:start position:0% +would this keep the same energy when +would the energy of these of of that + + align:start position:0% +would the energy of these of of that + + + align:start position:0% +would the energy of these of of that +when when would this have constant + + align:start position:0% +when when would this have constant + + + align:start position:0% +when when would this have constant +energy constant + + align:start position:0% +energy constant + + + align:start position:0% +energy constant +length the length would be constant + + align:start position:0% +length the length would be constant + + + align:start position:0% +length the length would be constant +since X is certainly that's a igen + + align:start position:0% +since X is certainly that's a igen + + + align:start position:0% +since X is certainly that's a igen +vector whatever it is this is what's + + align:start position:0% +vector whatever it is this is what's + + + align:start position:0% +vector whatever it is this is what's +changing and now I want to know when + + align:start position:0% +changing and now I want to know when + + + align:start position:0% +changing and now I want to know when +does the length not change well the test + + align:start position:0% +does the length not change well the test + + + align:start position:0% +does the length not change well the test +would be that this number should have + + align:start position:0% +would be that this number should have + + + align:start position:0% +would be that this number should have +absolute + + align:start position:0% +absolute + + + align:start position:0% +absolute +value one right if this has if this + + align:start position:0% +value one right if this has if this + + + align:start position:0% +value one right if this has if this +keeps absolute value one then then in + + align:start position:0% +keeps absolute value one then then in + + + align:start position:0% +keeps absolute value one then then in +the igen value picture I have energy + + align:start position:0% +the igen value picture I have energy + + + align:start position:0% +the igen value picture I have energy +staying the same okay now when will this + + align:start position:0% +staying the same okay now when will this + + + align:start position:0% +staying the same okay now when will this +have when will this have magnitude one + + align:start position:0% +have when will this have magnitude one + + + align:start position:0% +have when will this have magnitude one +time is running along this is e to the + + align:start position:0% +time is running along this is e to the + + + align:start position:0% +time is running along this is e to the +Lambda T so which + + align:start position:0% +Lambda T so which + + + align:start position:0% +Lambda T so which +lambdas zero certainly but now there's + + align:start position:0% +lambdas zero certainly but now there's + + + align:start position:0% +lambdas zero certainly but now there's +more you got to know the others what + + align:start position:0% +more you got to know the others what + + + align:start position:0% +more you got to know the others what +other lambdas will have what other + + align:start position:0% +other lambdas will have what other + + + align:start position:0% +other lambdas will have what other +lambdas give me this thing stays on the + + align:start position:0% +lambdas give me this thing stays on the + + + align:start position:0% +lambdas give me this thing stays on the +unit circle absolute value one key key + + align:start position:0% +unit circle absolute value one key key + + + align:start position:0% +unit circle absolute value one key key +question you you must know Lambda could + + align:start position:0% +question you you must know Lambda could + + + align:start position:0% +question you you must know Lambda could +be imaginary Lambda could be imaginary + + align:start position:0% +be imaginary Lambda could be imaginary + + + align:start position:0% +be imaginary Lambda could be imaginary +right Lambda could be imaginary e to the + + align:start position:0% +right Lambda could be imaginary e to the + + + align:start position:0% +right Lambda could be imaginary e to the +I Omega T those you know we don't you + + align:start position:0% +I Omega T those you know we don't you + + + align:start position:0% +I Omega T those you know we don't you +know those that that's just like basic + + align:start position:0% +know those that that's just like basic + + + align:start position:0% +know those that that's just like basic +fact about complex numbers that if + + align:start position:0% +fact about complex numbers that if + + + align:start position:0% +fact about complex numbers that if +Lambda is imaginary we have we would + + align:start position:0% +Lambda is imaginary we have we would + + + align:start position:0% +Lambda is imaginary we have we would +have the cosine of something t plus I * + + align:start position:0% +have the cosine of something t plus I * + + + align:start position:0% +have the cosine of something t plus I * +the S of something T cos square plus sin + + align:start position:0% +the S of something T cos square plus sin + + + align:start position:0% +the S of something T cos square plus sin +Square being 1 we'd be on the unit + + align:start position:0% +Square being 1 we'd be on the unit + + + align:start position:0% +Square being 1 we'd be on the unit +circle so we want from this picture we + + align:start position:0% +circle so we want from this picture we + + + align:start position:0% +circle so we want from this picture we +would want the lambdas to be pure + + align:start position:0% +would want the lambdas to be pure + + + align:start position:0% +would want the lambdas to be pure +imaginary and now a little Next + + align:start position:0% +imaginary and now a little Next + + + align:start position:0% +imaginary and now a little Next +Step what we'd like for the igen + + align:start position:0% +Step what we'd like for the igen + + + align:start position:0% +Step what we'd like for the igen +vectors + + align:start position:0% +vectors + + + align:start position:0% +vectors +let me because the real solution will + + align:start position:0% +let me because the real solution will + + + align:start position:0% +let me because the real solution will +not be just one of these + + align:start position:0% +not be just one of these + + + align:start position:0% +not be just one of these +guys but a + + align:start position:0% +guys but a + + + align:start position:0% +guys but a +combination so when we have a + + align:start position:0% +combination so when we have a + + + align:start position:0% +combination so when we have a +combination each one is doing its thing + + align:start position:0% +combination each one is doing its thing + + + align:start position:0% +combination each one is doing its thing +each one better have Lambda imaginary + + align:start position:0% +each one better have Lambda imaginary + + + align:start position:0% +each one better have Lambda imaginary +but more than + + align:start position:0% +but more than + + + align:start position:0% +but more than +that + + align:start position:0% +that + + + align:start position:0% +that +if the we would want the X's to be + + align:start position:0% +if the we would want the X's to be + + + align:start position:0% +if the we would want the X's to be +perpendicular because if the X's + + align:start position:0% +perpendicular because if the X's + + + align:start position:0% +perpendicular because if the X's +interact then this guy one of + + align:start position:0% +interact then this guy one of + + + align:start position:0% +interact then this guy one of +these you will say there's 's only one + + align:start position:0% +these you will say there's 's only one + + + align:start position:0% +these you will say there's 's only one +there but I'm thinking of n of them + + align:start position:0% +there but I'm thinking of n of them + + + align:start position:0% +there but I'm thinking of n of them +there a combination say two of them + + align:start position:0% +there a combination say two of them + + + align:start position:0% +there a combination say two of them +suppose I have an e to the Lambda 1 tx1 + + align:start position:0% +suppose I have an e to the Lambda 1 tx1 + + + align:start position:0% +suppose I have an e to the Lambda 1 tx1 +and an e to the Lambda 2 tx2 when does + + align:start position:0% +and an e to the Lambda 2 tx2 when does + + + align:start position:0% +and an e to the Lambda 2 tx2 when does +that conserve energy well the each one + + align:start position:0% +that conserve energy well the each one + + + align:start position:0% +that conserve energy well the each one +will but the + + align:start position:0% +will but the + + + align:start position:0% +will but the +combination will be fine if the X's are + + align:start position:0% +combination will be fine if the X's are + + + align:start position:0% +combination will be fine if the X's are +perpendicular because if I have + + align:start position:0% +perpendicular because if I have + + + align:start position:0% +perpendicular because if I have +perpendicular vectors then the length of + + align:start position:0% +perpendicular vectors then the length of + + + align:start position:0% +perpendicular vectors then the length of +the whole combination is by pagas is + + align:start position:0% +the whole combination is by pagas is + + + align:start position:0% +the whole combination is by pagas is +just one squar and the other squared and + + align:start position:0% +just one squar and the other squared and + + + align:start position:0% +just one squar and the other squared and +each of those pieces is + + align:start position:0% +each of those pieces is + + + align:start position:0% +each of those pieces is +constant let me say what I'm trying to + + align:start position:0% +constant let me say what I'm trying to + + + align:start position:0% +constant let me say what I'm trying to +say that the igen value igen function + + align:start position:0% +say that the igen value igen function + + + align:start position:0% +say that the igen value igen function +picture also tells us that we would like + + align:start position:0% +picture also tells us that we would like + + + align:start position:0% +picture also tells us that we would like +imaginary igen values and perpendicular + + align:start position:0% +imaginary igen values and perpendicular + + + align:start position:0% +imaginary igen values and perpendicular +IG vectors and that is exactly what you + + align:start position:0% +IG vectors and that is exactly what you + + + align:start position:0% +IG vectors and that is exactly what you +get from a transpose equal minus a so a + + align:start position:0% +get from a transpose equal minus a so a + + + align:start position:0% +get from a transpose equal minus a so a +transpose equal minus a is exactly get + + align:start position:0% +transpose equal minus a is exactly get + + + align:start position:0% +transpose equal minus a is exactly get +you those matrices anti-symmetric + + align:start position:0% +you those matrices anti-symmetric + + + align:start position:0% +you those matrices anti-symmetric +matrices have perpendicular IG vectors + + align:start position:0% +matrices have perpendicular IG vectors + + + align:start position:0% +matrices have perpendicular IG vectors +just like symmetric but the igen values + + align:start position:0% +just like symmetric but the igen values + + + align:start position:0% +just like symmetric but the igen values +are pure imaginary instead of all being + + align:start position:0% +are pure imaginary instead of all being + + + align:start position:0% +are pure imaginary instead of all being +real they're all pure imaginary in other + + align:start position:0% +real they're all pure imaginary in other + + + align:start position:0% +real they're all pure imaginary in other +words that answer and the discussion + + align:start position:0% +words that answer and the discussion + + + align:start position:0% +words that answer and the discussion +here came to the same conclusion okay + + align:start position:0% +here came to the same conclusion okay + + + align:start position:0% +here came to the same conclusion okay +that a should be anti-symmetric okay now + + align:start position:0% +that a should be anti-symmetric okay now + + + align:start position:0% +that a should be anti-symmetric okay now +let's now let me look at ready is that + + align:start position:0% +let's now let me look at ready is that + + + align:start position:0% +let's now let me look at ready is that +okay that so that's a discussion which + + align:start position:0% +okay that so that's a discussion which + + + align:start position:0% +okay that so that's a discussion which +is worth knowing about differential + + align:start position:0% +is worth knowing about differential + + + align:start position:0% +is worth knowing about differential +equations when are when is energy + + align:start position:0% +equations when are when is energy + + + align:start position:0% +equations when are when is energy +conserved now I want to do or the + + align:start position:0% +conserved now I want to do or the + + + align:start position:0% +conserved now I want to do or the +problem asked me to do what about this + + align:start position:0% +problem asked me to do what about this + + + align:start position:0% +problem asked me to do what about this +difference equation when is energy + + align:start position:0% +difference equation when is energy + + + align:start position:0% +difference equation when is energy +conserved there and I + + align:start position:0% +conserved there and I + + + align:start position:0% +conserved there and I +guess uh I believe it will be I if it's + + align:start position:0% +guess uh I believe it will be I if it's + + + align:start position:0% +guess uh I believe it will be I if it's +this is the requirement for the + + align:start position:0% +this is the requirement for the + + + align:start position:0% +this is the requirement for the +differential equation to be okay to + + align:start position:0% +differential equation to be okay to + + + align:start position:0% +differential equation to be okay to +conserve energy and so I'm going to + + align:start position:0% +conserve energy and so I'm going to + + + align:start position:0% +conserve energy and so I'm going to +expect I'm going to need that in this + + align:start position:0% +expect I'm going to need that in this + + + align:start position:0% +expect I'm going to need that in this +one and is that enough I if I have this + + align:start position:0% +one and is that enough I if I have this + + + align:start position:0% +one and is that enough I if I have this +a transpose equal minus a + + align:start position:0% +a transpose equal minus a + + + align:start position:0% +a transpose equal minus a +anti-symmetric it was good for this is + + align:start position:0% +anti-symmetric it was good for this is + + + align:start position:0% +anti-symmetric it was good for this is +it also does it also do the job here is + + align:start position:0% +it also does it also do the job here is + + + align:start position:0% +it also does it also do the job here is +the is this trapezoidal method just cool + + align:start position:0% +the is this trapezoidal method just cool + + + align:start position:0% +the is this trapezoidal method just cool +so that it will conserve energy too and + + align:start position:0% +so that it will conserve energy too and + + + align:start position:0% +so that it will conserve energy too and +the answer I think is yes and the + + align:start position:0% +the answer I think is yes and the + + + align:start position:0% +the answer I think is yes and the +problem was to prove it or to see why + + align:start position:0% +problem was to prove it or to see why + + + align:start position:0% +problem was to prove it or to see why +why is so I I what do I now + + align:start position:0% +why is so I I what do I now + + + align:start position:0% +why is so I I what do I now +want if if you don't mind my erasing I'm + + align:start position:0% +want if if you don't mind my erasing I'm + + + align:start position:0% +want if if you don't mind my erasing I'm +now going to look at the at the uh + + align:start position:0% +now going to look at the at the uh + + + align:start position:0% +now going to look at the at the uh +discreet guy so now I'm looking at when + + align:start position:0% +discreet guy so now I'm looking at when + + + align:start position:0% +discreet guy so now I'm looking at when +is UN n + 1^ 2 equal un^ + + align:start position:0% +is UN n + 1^ 2 equal un^ + + + align:start position:0% +is UN n + 1^ 2 equal un^ +2 that's what I mean by conserving + + align:start position:0% +2 that's what I mean by conserving + + + align:start position:0% +2 that's what I mean by conserving +energy in the discret case at every step + + align:start position:0% +energy in the discret case at every step + + + align:start position:0% +energy in the discret case at every step +same energy so now I want to look at the + + align:start position:0% +same energy so now I want to look at the + + + align:start position:0% +same energy so now I want to look at the +energy in un n + one compared to the + + align:start position:0% +energy in un n + one compared to the + + + align:start position:0% +energy in un n + one compared to the +energy in un and I want to see that this + + align:start position:0% +energy in un and I want to see that this + + + align:start position:0% +energy in un and I want to see that this +is the this holds + + align:start position:0% +is the this holds + + + align:start position:0% +is the this holds +uh probably there's some smart way to do + + align:start position:0% + + + + align:start position:0% + +that it's now we're now we're down to + + align:start position:0% +that it's now we're now we're down to + + + align:start position:0% +that it's now we're now we're down to +just like the math question you know + + align:start position:0% +just like the math question you know + + + align:start position:0% +just like the math question you know +math is always looking for some you just + + align:start position:0% +math is always looking for some you just + + + align:start position:0% +math is always looking for some you just +sort of do the right thing and stand + + align:start position:0% +sort of do the right thing and stand + + + align:start position:0% +sort of do the right thing and stand +back and poof it it it it works okay so + + align:start position:0% +back and poof it it it it works okay so + + + align:start position:0% +back and poof it it it it works okay so +what's the right thing hopefully I have + + align:start position:0% +what's the right thing hopefully I have + + + align:start position:0% +what's the right thing hopefully I have +helped you and me by saying what what + + align:start position:0% +helped you and me by saying what what + + + align:start position:0% +helped you and me by saying what what +would be a good idea to do here can I + + align:start position:0% +would be a good idea to do here can I + + + align:start position:0% +would be a good idea to do here can I +just + + align:start position:0% + + + + align:start position:0% + +look okay it + + align:start position:0% +look okay it + + + align:start position:0% +look okay it +says oh does it say what to + + align:start position:0% +says oh does it say what to + + + align:start position:0% +says oh does it say what to +do yeah it says + + align:start position:0% +do yeah it says + + + align:start position:0% +do yeah it says +multiply by un n + 1 minus plus un n + + align:start position:0% +multiply by un n + 1 minus plus un n + + + align:start position:0% +multiply by un n + 1 minus plus un n +take the take the dotproduct is that + + align:start position:0% +take the take the dotproduct is that + + + align:start position:0% +take the take the dotproduct is that +that's interesting take the dot product + + align:start position:0% +that's interesting take the dot product + + + align:start position:0% +that's interesting take the dot product +so why did that work take the dot + + align:start position:0% +so why did that work take the dot + + + align:start position:0% +so why did that work take the dot +product of both sides with with un n + + + align:start position:0% +product of both sides with with un n + + + + align:start position:0% +product of both sides with with un n + +1us u n is that did anybody succeed with + + align:start position:0% +1us u n is that did anybody succeed with + + + align:start position:0% +1us u n is that did anybody succeed with +this + + align:start position:0% +this + + + align:start position:0% +this +idea but that's the idea is and and and + + align:start position:0% +idea but that's the idea is and and and + + + align:start position:0% +idea but that's the idea is and and and +hopefully uh we'll get it to work that + + align:start position:0% +hopefully uh we'll get it to work that + + + align:start position:0% +hopefully uh we'll get it to work that +if I multiply both sides by un + 1 oh no + + align:start position:0% +if I multiply both sides by un + 1 oh no + + + align:start position:0% +if I multiply both sides by un + 1 oh no +plus un maybe better if I look at it + + align:start position:0% +plus un maybe better if I look at it + + + align:start position:0% +plus un maybe better if I look at it +this way I'm yeah I'm sort of okay to do + + align:start position:0% +this way I'm yeah I'm sort of okay to do + + + align:start position:0% +this way I'm yeah I'm sort of okay to do +it that way suppose I multiply both + + align:start position:0% +it that way suppose I multiply both + + + align:start position:0% +it that way suppose I multiply both +sides so now I'm following on this idea + + align:start position:0% +sides so now I'm following on this idea + + + align:start position:0% +sides so now I'm following on this idea +I've that equation I've Rewritten here + + align:start position:0% +I've that equation I've Rewritten here + + + align:start position:0% +I've that equation I've Rewritten here +and without practice I don't know which + + align:start position:0% +and without practice I don't know which + + + align:start position:0% +and without practice I don't know which +one is the good one to start with but I + + align:start position:0% +one is the good one to start with but I + + + align:start position:0% +one is the good one to start with but I +I'm pretty okay with starting with this + + align:start position:0% +I'm pretty okay with starting with this + + + align:start position:0% +I'm pretty okay with starting with this +one suppose I so what what's my idea + + align:start position:0% +one suppose I so what what's my idea + + + align:start position:0% +one suppose I so what what's my idea +that's my equation now I'm going to + + align:start position:0% +that's my equation now I'm going to + + + align:start position:0% +that's my equation now I'm going to +multiply both sides + + align:start position:0% +multiply both sides + + + align:start position:0% +multiply both sides +by un n + 1 plus un transpose now I + + align:start position:0% +by un n + 1 plus un transpose now I + + + align:start position:0% +by un n + 1 plus un transpose now I +don't have room to do it unfortunately I + + align:start position:0% +don't have room to do it unfortunately I + + + align:start position:0% +don't have room to do it unfortunately I +want to stick in here un plus with a + + align:start position:0% +want to stick in here un plus with a + + + align:start position:0% +want to stick in here un plus with a +plus sign in there and of course I have + + align:start position:0% +plus sign in there and of course I have + + + align:start position:0% +plus sign in there and of course I have +to do the same thing here okay are you + + align:start position:0% +to do the same thing here okay are you + + + align:start position:0% +to do the same thing here okay are you +okay do you see what I'm + + align:start position:0% +okay do you see what I'm + + + align:start position:0% +okay do you see what I'm +doing I I I want to show that this + + align:start position:0% +doing I I I want to show that this + + + align:start position:0% +doing I I I want to show that this +equation which is the same as this + + align:start position:0% +equation which is the same as this + + + align:start position:0% +equation which is the same as this +equation has this + + align:start position:0% +equation has this + + + align:start position:0% +equation has this +property which is a copy of this + + align:start position:0% +property which is a copy of this + + + align:start position:0% +property which is a copy of this +property here here would be another way + + align:start position:0% +property here here would be another way + + + align:start position:0% +property here here would be another way +to do it I mean just we could do it + + align:start position:0% +to do it I mean just we could do it + + + align:start position:0% +to do it I mean just we could do it +the the the way we're going to do it now + + align:start position:0% +the the the way we're going to do it now + + + align:start position:0% +the the the way we're going to do it now +is sort of compare Compares with the way + + align:start position:0% +is sort of compare Compares with the way + + + align:start position:0% +is sort of compare Compares with the way +we started with the derivative of the + + align:start position:0% +we started with the derivative of the + + + align:start position:0% +we started with the derivative of the +norm squar I could also ask the same + + align:start position:0% +norm squar I could also ask the same + + + align:start position:0% +norm squar I could also ask the same +question by following igen + + align:start position:0% +question by following igen + + + align:start position:0% +question by following igen +vectors I could also ask the same + + align:start position:0% +vectors I could also ask the same + + + align:start position:0% +vectors I could also ask the same +question by following igen vectors I I + + align:start position:0% +question by following igen vectors I I + + + align:start position:0% +question by following igen vectors I I +get I'm guessing that here the igen + + align:start position:0% +get I'm guessing that here the igen + + + align:start position:0% +get I'm guessing that here the igen +values un + one is yeah uh yeah you see + + align:start position:0% +values un + one is yeah uh yeah you see + + + align:start position:0% +values un + one is yeah uh yeah you see +I could could do it both ways I maybe + + align:start position:0% +I could could do it both ways I maybe + + + align:start position:0% +I could could do it both ways I maybe +having just done igen vectors let me do + + align:start position:0% +having just done igen vectors let me do + + + align:start position:0% +having just done igen vectors let me do +this one by igen vectors so what are the + + align:start position:0% +this one by igen vectors so what are the + + + align:start position:0% +this one by igen vectors so what are the +an igen Vector of + + align:start position:0% +an igen Vector of + + + align:start position:0% +an igen Vector of +a one of X itself is what happens to + + align:start position:0% +a one of X itself is what happens to + + + align:start position:0% +a one of X itself is what happens to +anigen Vector suppose U is an igen + + align:start position:0% +anigen Vector suppose U is an igen + + + align:start position:0% +anigen Vector suppose U is an igen +Vector X of a what's U1 yeah you really + + align:start position:0% +Vector X of a what's U1 yeah you really + + + align:start position:0% +Vector X of a what's U1 yeah you really +should see this question so if if u0 is + + align:start position:0% +should see this question so if if u0 is + + + align:start position:0% +should see this question so if if u0 is +the IG Vector + + align:start position:0% +the IG Vector + + + align:start position:0% +the IG Vector +X then what is + + align:start position:0% + + + + align:start position:0% + +U1 let me just write here a X equaling + + align:start position:0% +U1 let me just write here a X equaling + + + align:start position:0% +U1 let me just write here a X equaling +Lambda X so these are the igen values of + + align:start position:0% +Lambda X so these are the igen values of + + + align:start position:0% +Lambda X so these are the igen values of +a and now I want to and we've learned + + align:start position:0% +a and now I want to and we've learned + + + align:start position:0% +a and now I want to and we've learned +that they're pure imaginary in this case + + align:start position:0% +that they're pure imaginary in this case + + + align:start position:0% +that they're pure imaginary in this case +when we're ready to go and now I'd like + + align:start position:0% +when we're ready to go and now I'd like + + + align:start position:0% +when we're ready to go and now I'd like +to know that + + align:start position:0% +to know that + + + align:start position:0% +to know that +there that we get the good thing here + + align:start position:0% +there that we get the good thing here + + + align:start position:0% +there that we get the good thing here +okay so what if un is the is an igen + + align:start position:0% +okay so what if un is the is an igen + + + align:start position:0% +okay so what if un is the is an igen +Vector what is UN n + + + align:start position:0% +Vector what is UN n + + + + align:start position:0% +Vector what is UN n + +one okay so can I just do that that un n + + align:start position:0% +one okay so can I just do that that un n + + + align:start position:0% +one okay so can I just do that that un n ++ 1 + + align:start position:0% ++ 1 + + + align:start position:0% ++ 1 +is what do I have on that right hand + + align:start position:0% +is what do I have on that right hand + + + align:start position:0% +is what do I have on that right hand +side x and what is + + align:start position:0% +side x and what is + + + align:start position:0% +side x and what is +ax it's Lambda right it's Lambda X so so + + align:start position:0% +ax it's Lambda right it's Lambda X so so + + + align:start position:0% +ax it's Lambda right it's Lambda X so so +all this is 1 + Lambda delta T on 2 + + align:start position:0% +all this is 1 + Lambda delta T on 2 + + + align:start position:0% +all this is 1 + Lambda delta T on 2 +x but now I've also got to hit it bring + + align:start position:0% +x but now I've also got to hit it bring + + + align:start position:0% +x but now I've also got to hit it bring +this guy over here here it's + + align:start position:0% +this guy over here here it's + + + align:start position:0% +this guy over here here it's +inverse and see what that does now it's + + align:start position:0% +inverse and see what that does now it's + + + align:start position:0% +inverse and see what that does now it's +the inverse so it's it's going to have + + align:start position:0% +the inverse so it's it's going to have + + + align:start position:0% +the inverse so it's it's going to have +the same igen vector and the igen value + + align:start position:0% +the same igen vector and the igen value + + + align:start position:0% +the same igen vector and the igen value +is going to go in the denominator and + + align:start position:0% +is going to go in the denominator and + + + align:start position:0% +is going to go in the denominator and +it'll be one minus delta T Lambda delta + + align:start position:0% +it'll be one minus delta T Lambda delta + + + align:start position:0% +it'll be one minus delta T Lambda delta +T / + + align:start position:0% + + + + align:start position:0% + +2 okay so that's un + one is do you see + + align:start position:0% +2 okay so that's un + one is do you see + + + align:start position:0% +2 okay so that's un + one is do you see +what's happening + + align:start position:0% +what's happening + + + align:start position:0% +what's happening +here the igen vector + + align:start position:0% +here the igen vector + + + align:start position:0% +here the igen vector +X if if we start with that ion Vector X + + align:start position:0% +X if if we start with that ion Vector X + + + align:start position:0% +X if if we start with that ion Vector X +we come out with a multiple of X and + + align:start position:0% +we come out with a multiple of X and + + + align:start position:0% +we come out with a multiple of X and +this is the + + align:start position:0% +this is the + + + align:start position:0% +this is the +multiple so each each finite difference + + align:start position:0% +multiple so each each finite difference + + + align:start position:0% +multiple so each each finite difference +step multiplies by a number just the way + + align:start position:0% +step multiplies by a number just the way + + + align:start position:0% +step multiplies by a number just the way +each in the continuous case we were + + align:start position:0% +each in the continuous case we were + + + align:start position:0% +each in the continuous case we were +multiplying by e to the Lambda T and in + + align:start position:0% +multiplying by e to the Lambda T and in + + + align:start position:0% +multiplying by e to the Lambda T and in +the continuous in the discrete + + align:start position:0% +the continuous in the discrete + + + align:start position:0% +the continuous in the discrete +stepbystep case we're multiplying by + + align:start position:0% +stepbystep case we're multiplying by + + + align:start position:0% +stepbystep case we're multiplying by +that + + align:start position:0% +that + + + align:start position:0% +that +number actually this is why problem + + align:start position:0% +number actually this is why problem + + + align:start position:0% +number actually this is why problem +seven is important + + align:start position:0% +seven is important + + + align:start position:0% +seven is important +because if we want to know how accurate + + align:start position:0% +because if we want to know how accurate + + + align:start position:0% +because if we want to know how accurate +the comparison is I want to compare e to + + align:start position:0% +the comparison is I want to compare e to + + + align:start position:0% +the comparison is I want to compare e to +the Lambda t with that + + align:start position:0% +the Lambda t with that + + + align:start position:0% +the Lambda t with that +number but so i' problem six is is is + + align:start position:0% +number but so i' problem six is is is + + + align:start position:0% +number but so i' problem six is is is +asking about a question about that ratio + + align:start position:0% +asking about a question about that ratio + + + align:start position:0% +asking about a question about that ratio +and problem seven is asking another + + align:start position:0% +and problem seven is asking another + + + align:start position:0% +and problem seven is asking another +question about that very same ratio now + + align:start position:0% +question about that very same ratio now + + + align:start position:0% +question about that very same ratio now +what's the question for problem six when + + align:start position:0% +what's the question for problem six when + + + align:start position:0% +what's the question for problem six when +will this vector have the same length as + + align:start position:0% +will this vector have the same length as + + + align:start position:0% +will this vector have the same length as +as this x was UN + + align:start position:0% +as this x was UN + + + align:start position:0% +as this x was UN +n what what am + + align:start position:0% +n what what am + + + align:start position:0% +n what what am +I so I started with a + + align:start position:0% +I so I started with a + + + align:start position:0% +I so I started with a +un I multiplied by this number to get un + + align:start position:0% +un I multiplied by this number to get un + + + align:start position:0% +un I multiplied by this number to get un +n + one when do they have the same + + align:start position:0% +n + one when do they have the same + + + align:start position:0% +n + one when do they have the same +length when that number has absolute + + align:start position:0% +length when that number has absolute + + + align:start position:0% +length when that number has absolute +value one so that's my if I watching + + align:start position:0% +value one so that's my if I watching + + + align:start position:0% +value one so that's my if I watching +igen + + align:start position:0% +igen + + + align:start position:0% +igen +vectors this guy had absolute value one + + align:start position:0% +vectors this guy had absolute value one + + + align:start position:0% +vectors this guy had absolute value one +cuz Lambda was + + align:start position:0% +cuz Lambda was + + + align:start position:0% +cuz Lambda was +imaginary now what about this guy + + align:start position:0% +imaginary now what about this guy + + + align:start position:0% +imaginary now what about this guy +lambda's still that same Lambda + + align:start position:0% +lambda's still that same Lambda + + + align:start position:0% +lambda's still that same Lambda +imaginary what what can you tell me + + align:start position:0% +imaginary what what can you tell me + + + align:start position:0% +imaginary what what can you tell me +about one plus so Lambda is some I Omega + + align:start position:0% +about one plus so Lambda is some I Omega + + + align:start position:0% +about one plus so Lambda is some I Omega +delta T / 2 and down here I have 1 minus + + align:start position:0% +delta T / 2 and down here I have 1 minus + + + align:start position:0% +delta T / 2 and down here I have 1 minus +I Omega that's the Lambda Delta t/ 2 I I + + align:start position:0% +I Omega that's the Lambda Delta t/ 2 I I + + + align:start position:0% +I Omega that's the Lambda Delta t/ 2 I I +believe that that does have absolute + + align:start position:0% +believe that that does have absolute + + + align:start position:0% +believe that that does have absolute +value one + + align:start position:0% + + + + align:start position:0% + +anybody tell me why so that this is + + align:start position:0% +anybody tell me why so that this is + + + align:start position:0% +anybody tell me why so that this is +checking that uh um energy is conserved + + align:start position:0% +checking that uh um energy is conserved + + + align:start position:0% +checking that uh um energy is conserved +for each igen + + align:start position:0% +for each igen + + + align:start position:0% +for each igen +Vector the energy because the because + + align:start position:0% +Vector the energy because the because + + + align:start position:0% +Vector the energy because the because +the I Vector is multiplied by that + + align:start position:0% +the I Vector is multiplied by that + + + align:start position:0% +the I Vector is multiplied by that +number and and that's some number it's + + align:start position:0% +number and and that's some number it's + + + align:start position:0% +number and and that's some number it's +some complex number but I believe it has + + align:start position:0% +some complex number but I believe it has + + + align:start position:0% +some complex number but I believe it has +absolute value one and I believe you can + + align:start position:0% +absolute value one and I believe you can + + + align:start position:0% +absolute value one and I believe you can +tell me why yeah comp because they're + + align:start position:0% +tell me why yeah comp because they're + + + align:start position:0% +tell me why yeah comp because they're +complex conjugates + + align:start position:0% +complex conjugates + + + align:start position:0% +complex conjugates +this numerator and the denominator are + + align:start position:0% +this numerator and the denominator are + + + align:start position:0% +this numerator and the denominator are +complex conjugates in the in the in the + + align:start position:0% +complex conjugates in the in the in the + + + align:start position:0% +complex conjugates in the in the in the +complex plane here's the one and I go up + + align:start position:0% +complex plane here's the one and I go up + + + align:start position:0% +complex plane here's the one and I go up +an e to the I go up I I Omega delta T + + align:start position:0% +an e to the I go up I I Omega delta T + + + align:start position:0% +an e to the I go up I I Omega delta T +over2 or in this one I go down by either + + align:start position:0% +over2 or in this one I go down by either + + + align:start position:0% +over2 or in this one I go down by either +I but those lengths are the same that + + align:start position:0% +I but those lengths are the same that + + + align:start position:0% +I but those lengths are the same that +numerator the length of the numerator is + + align:start position:0% +numerator the length of the numerator is + + + align:start position:0% +numerator the length of the numerator is +that guy the length of the denominator + + align:start position:0% +that guy the length of the denominator + + + align:start position:0% +that guy the length of the denominator +is this guy and their ratio is one + + align:start position:0% +is this guy and their ratio is one + + + align:start position:0% +is this guy and their ratio is one +so I think that this gives us the the + + align:start position:0% +so I think that this gives us the the + + + align:start position:0% +so I think that this gives us the the +point about complex numbers that that a + + align:start position:0% +point about complex numbers that that a + + + align:start position:0% +point about complex numbers that that a +complex number and its + + align:start position:0% +complex number and its + + + align:start position:0% +complex number and its +conjugate automatically have ratio of + + align:start position:0% +conjugate automatically have ratio of + + + align:start position:0% +conjugate automatically have ratio of +magnitude one you you see the difference + + align:start position:0% +magnitude one you you see the difference + + + align:start position:0% +magnitude one you you see the difference +between Oilers method so Oilers method + + align:start position:0% +between Oilers method so Oilers method + + + align:start position:0% +between Oilers method so Oilers method +for so forward Oiler forward forward + + align:start position:0% +for so forward Oiler forward forward + + + align:start position:0% +for so forward Oiler forward forward +Oiler would not have had + + align:start position:0% +Oiler would not have had + + + align:start position:0% +Oiler would not have had +this + + align:start position:0% +this + + + align:start position:0% +this +implicit this stuff on the left side it + + align:start position:0% +implicit this stuff on the left side it + + + align:start position:0% +implicit this stuff on the left side it +would all have been on the right hand + + align:start position:0% +would all have been on the right hand + + + align:start position:0% +would all have been on the right hand +side forward Oiler would have been about + + align:start position:0% +side forward Oiler would have been about + + + align:start position:0% +side forward Oiler would have been about +I + a delta T delta T A and what are its + + align:start position:0% +I + a delta T delta T A and what are its + + + align:start position:0% +I + a delta T delta T A and what are its +igen values 1 + I Omega delta + + align:start position:0% +igen values 1 + I Omega delta + + + align:start position:0% +igen values 1 + I Omega delta +T right with no no we're not dividing by + + align:start position:0% +T right with no no we're not dividing by + + + align:start position:0% +T right with no no we're not dividing by +anybody it's this part is is up top too + + align:start position:0% +anybody it's this part is is up top too + + + align:start position:0% +anybody it's this part is is up top too +so it's 1 plus I Omega delta T now does + + align:start position:0% +so it's 1 plus I Omega delta T now does + + + align:start position:0% +so it's 1 plus I Omega delta T now does +that have absolute value + + align:start position:0% +that have absolute value + + + align:start position:0% +that have absolute value +one well you know from the way I'm + + align:start position:0% +one well you know from the way I'm + + + align:start position:0% +one well you know from the way I'm +asking the question what can you tell me + + align:start position:0% +asking the question what can you tell me + + + align:start position:0% +asking the question what can you tell me +about the absolute value of that of the + + align:start position:0% +about the absolute value of that of the + + + align:start position:0% +about the absolute value of that of the +forward Oiler growth factor greater than + + align:start position:0% +forward Oiler growth factor greater than + + + align:start position:0% +forward Oiler growth factor greater than +one because this is the one and this is + + align:start position:0% +one because this is the one and this is + + + align:start position:0% +one because this is the one and this is +the I Omega delta T maybe went up twice + + align:start position:0% +the I Omega delta T maybe went up twice + + + align:start position:0% +the I Omega delta T maybe went up twice +as far and there was nobody divide by + + align:start position:0% +as far and there was nobody divide by + + + align:start position:0% +as far and there was nobody divide by +it's bigger than one so it blows up and + + align:start position:0% +it's bigger than one so it blows up and + + + align:start position:0% +it's bigger than one so it blows up and +the backward Oiler had only the only the + + align:start position:0% +the backward Oiler had only the only the + + + align:start position:0% +the backward Oiler had only the only the +1 over 1 minus I Omega delta T so the + + align:start position:0% +1 over 1 minus I Omega delta T so the + + + align:start position:0% +1 over 1 minus I Omega delta T so the +backward was was like this like one over + + align:start position:0% +backward was was like this like one over + + + align:start position:0% +backward was was like this like one over +it and less than one but this balance + + align:start position:0% +it and less than one but this balance + + + align:start position:0% +it and less than one but this balance +has absolute value equal one so okay + + align:start position:0% +has absolute value equal one so okay + + + align:start position:0% +has absolute value equal one so okay +that's that's the sort of Heart of + + align:start position:0% +that's that's the sort of Heart of + + + align:start position:0% +that's that's the sort of Heart of +what's going on can I before I tackle + + align:start position:0% +what's going on can I before I tackle + + + align:start position:0% +what's going on can I before I tackle +the question using the hint there uh + + align:start position:0% +the question using the hint there uh + + + align:start position:0% +the question using the hint there uh +which will take me on another Blackboard + + align:start position:0% +which will take me on another Blackboard + + + align:start position:0% +which will take me on another Blackboard +can I I discuss question seven were you + + align:start position:0% +can I I discuss question seven were you + + + align:start position:0% +can I I discuss question seven were you +going to ask me about number seven yeah + + align:start position:0% +going to ask me about number seven yeah + + + align:start position:0% +going to ask me about number seven yeah +I you were okay all right we get to + + align:start position:0% +I you were okay all right we get to + + + align:start position:0% +I you were okay all right we get to +answer okay so question seven is about + + align:start position:0% +answer okay so question seven is about + + + align:start position:0% +answer okay so question seven is about +the + + align:start position:0% +the + + + align:start position:0% +the +accuracy so here's the correct number + + align:start position:0% +accuracy so here's the correct number + + + align:start position:0% +accuracy so here's the correct number +this this is my e to the I Omega T + + align:start position:0% +this this is my e to the I Omega T + + + align:start position:0% +this this is my e to the I Omega T +that's the correct number that I should + + align:start position:0% +that's the correct number that I should + + + align:start position:0% +that's the correct number that I should +be multiplying by and the actual number + + align:start position:0% +be multiplying by and the actual number + + + align:start position:0% +be multiplying by and the actual number +that I'm multiplying by is that + + align:start position:0% +that I'm multiplying by is that + + + align:start position:0% +that I'm multiplying by is that +one or in the forward Oiler case it's + + align:start position:0% +one or in the forward Oiler case it's + + + align:start position:0% +one or in the forward Oiler case it's +that one and so I'm comparing the + + align:start position:0% +that one and so I'm comparing the + + + align:start position:0% +that one and so I'm comparing the +onestep accuracy so let me compare + + align:start position:0% +onestep accuracy so let me compare + + + align:start position:0% +onestep accuracy so let me compare +one-step + + align:start position:0% +one-step + + + align:start position:0% +one-step +accuracy yeah so this is this is the + + align:start position:0% +accuracy yeah so this is this is the + + + align:start position:0% +accuracy yeah so this is this is the +topic now of order of accuracy this is + + align:start position:0% +topic now of order of accuracy this is + + + align:start position:0% +topic now of order of accuracy this is +the question + + align:start position:0% +the question + + + align:start position:0% +the question +seven and it amounts to + + align:start position:0% +seven and it amounts to + + + align:start position:0% +seven and it amounts to +comparing the so what + + align:start position:0% +comparing the so what + + + align:start position:0% +comparing the so what +yeah what is one delta T Step In The + + align:start position:0% +yeah what is one delta T Step In The + + + align:start position:0% +yeah what is one delta T Step In The +Continuous case so so how much does the + + align:start position:0% +Continuous case so so how much does the + + + align:start position:0% +Continuous case so so how much does the +I Vector x what does it get multiplied + + align:start position:0% +I Vector x what does it get multiplied + + + align:start position:0% +I Vector x what does it get multiplied +by if I take a delta T step in the + + align:start position:0% +by if I take a delta T step in the + + + align:start position:0% +by if I take a delta T step in the +differential equation if I if I so this + + align:start position:0% +differential equation if I if I so this + + + align:start position:0% +differential equation if I if I so this +is the exact delta T step the the what + + align:start position:0% +is the exact delta T step the the what + + + align:start position:0% +is the exact delta T step the the what +the finite difference won't get exactly + + align:start position:0% +the finite difference won't get exactly + + + align:start position:0% +the finite difference won't get exactly +right what so the exact so step delta + + align:start position:0% + + + + align:start position:0% + +T the uh + + align:start position:0% +T the uh + + + align:start position:0% +T the uh +differential differential + + align:start position:0% + + + + align:start position:0% + +equation of course I always I'm looking + + align:start position:0% +equation of course I always I'm looking + + + align:start position:0% +equation of course I always I'm looking +at axal Lambda X the differential + + align:start position:0% +at axal Lambda X the differential + + + align:start position:0% +at axal Lambda X the differential +equation multiplies X by + + align:start position:0% + + + + align:start position:0% + +what what what's the the exact growth + + align:start position:0% +what what what's the the exact growth + + + align:start position:0% +what what what's the the exact growth +factor you could say if I if if if my + + align:start position:0% +factor you could say if I if if if my + + + align:start position:0% +factor you could say if I if if if my +equation is Du dtal Au that's the + + align:start position:0% +equation is Du dtal Au that's the + + + align:start position:0% +equation is Du dtal Au that's the +differential equation and I'm supposing + + align:start position:0% +differential equation and I'm supposing + + + align:start position:0% +differential equation and I'm supposing +that I'm on an igen Vector + + align:start position:0% +that I'm on an igen Vector + + + align:start position:0% +that I'm on an igen Vector +X so that the solution is is e to the I + + align:start position:0% +X so that the solution is is e to the I + + + align:start position:0% +X so that the solution is is e to the I +Omega t or e to the I Lambda X + + align:start position:0% + + + + align:start position:0% + +now what happened over a delta T step + + align:start position:0% +now what happened over a delta T step + + + align:start position:0% +now what happened over a delta T step +this this is the answer like running + + align:start position:0% +this this is the answer like running + + + align:start position:0% +this this is the answer like running +along for all time all I'm asking you to + + align:start position:0% +along for all time all I'm asking you to + + + align:start position:0% +along for all time all I'm asking you to +do is if the step is delta T + + align:start position:0% +do is if the step is delta T + + + align:start position:0% +do is if the step is delta T +what's that + + align:start position:0% +what's that + + + align:start position:0% +what's that +number I mean that number is telling us + + align:start position:0% +number I mean that number is telling us + + + align:start position:0% +number I mean that number is telling us +how much how much it grew in that delta + + align:start position:0% +how much how much it grew in that delta + + + align:start position:0% +how much how much it grew in that delta +T step and of course it's e to the I + + align:start position:0% +T step and of course it's e to the I + + + align:start position:0% +T step and of course it's e to the I +Omega delta + + align:start position:0% + + + + align:start position:0% + +T that's the exact growth factor that's + + align:start position:0% +T that's the exact growth factor that's + + + align:start position:0% +T that's the exact growth factor that's +G + + align:start position:0% + + + + align:start position:0% + +exact in one time step the I Vector gets + + align:start position:0% +exact in one time step the I Vector gets + + + align:start position:0% +exact in one time step the I Vector gets +multiplied by that because that's the + + align:start position:0% +multiplied by that because that's the + + + align:start position:0% +multiplied by that because that's the +amount of time that elapsed and what's + + align:start position:0% +amount of time that elapsed and what's + + + align:start position:0% +amount of time that elapsed and what's +the approximate growth the + + align:start position:0% +the approximate growth the + + + align:start position:0% +the approximate growth the +approximate the growth factor from + + align:start position:0% +approximate the growth factor from + + + align:start position:0% +approximate the growth factor from +trapezoidal is just what we wrote down + + align:start position:0% +trapezoidal is just what we wrote down + + + align:start position:0% +trapezoidal is just what we wrote down +here 1+ delta + + align:start position:0% +here 1+ delta + + + align:start position:0% +here 1+ delta +T or Lambda delta T yeah maybe I'll stay + + align:start position:0% +T or Lambda delta T yeah maybe I'll stay + + + align:start position:0% +T or Lambda delta T yeah maybe I'll stay +with + + align:start position:0% +with + + + align:start position:0% +with +Lambda uh rather than I + + align:start position:0% +Lambda uh rather than I + + + align:start position:0% +Lambda uh rather than I +Omega just e to the Lambda delta T and + + align:start position:0% +Omega just e to the Lambda delta T and + + + align:start position:0% +Omega just e to the Lambda delta T and +this was 1 + delta T / 2 Lambda / 1 us + + align:start position:0% +this was 1 + delta T / 2 Lambda / 1 us + + + align:start position:0% +this was 1 + delta T / 2 Lambda / 1 us +delta T / 2 + + align:start position:0% + + + + align:start position:0% + +Lambda so question s just says compare + + align:start position:0% +Lambda so question s just says compare + + + align:start position:0% +Lambda so question s just says compare +that with + + align:start position:0% +that with + + + align:start position:0% +that with +that if if thinking of delta T is a + + align:start position:0% +that if if thinking of delta T is a + + + align:start position:0% +that if if thinking of delta T is a +small time step if delta T is + + align:start position:0% +small time step if delta T is + + + align:start position:0% +small time step if delta T is +zero then of course the e to the 0 is + + align:start position:0% +zero then of course the e to the 0 is + + + align:start position:0% +zero then of course the e to the 0 is +one if delta T is zero I get one here + + align:start position:0% +one if delta T is zero I get one here + + + align:start position:0% +one if delta T is zero I get one here +they're correct if delta T is zero + + align:start position:0% +they're correct if delta T is zero + + + align:start position:0% +they're correct if delta T is zero +that's no big deal what what do I how do + + align:start position:0% +that's no big deal what what do I how do + + + align:start position:0% +that's no big deal what what do I how do +I study how do I understand what happens + + align:start position:0% +I study how do I understand what happens + + + align:start position:0% +I study how do I understand what happens +for small delta + + align:start position:0% + + + + align:start position:0% + +T this is like comparing I'm comparing + + align:start position:0% +T this is like comparing I'm comparing + + + align:start position:0% +T this is like comparing I'm comparing +this this this exponential for small + + align:start position:0% +this this this exponential for small + + + align:start position:0% +this this this exponential for small +delta T with this guy for small delta T + + align:start position:0% +delta T with this guy for small delta T + + + align:start position:0% +delta T with this guy for small delta T +how how do you make comparisons for + + align:start position:0% +how how do you make comparisons for + + + align:start position:0% +how how do you make comparisons for +small delta T well that's what Taylor + + align:start position:0% +small delta T well that's what Taylor + + + align:start position:0% +small delta T well that's what Taylor +series is all about let's do the tailor + + align:start position:0% +series is all about let's do the tailor + + + align:start position:0% +series is all about let's do the tailor +series what's the series for the + + align:start position:0% +series what's the series for the + + + align:start position:0% +series what's the series for the +exponential + + align:start position:0% +exponential + + + align:start position:0% +exponential +if if if delta T is small I have e to + + align:start position:0% +if if if delta T is small I have e to + + + align:start position:0% +if if if delta T is small I have e to +some little number tell me start me out + + align:start position:0% +some little number tell me start me out + + + align:start position:0% +some little number tell me start me out +on the + + align:start position:0% + + + + align:start position:0% + +exponential one thanks one plus uh right + + align:start position:0% +exponential one thanks one plus uh right + + + align:start position:0% +exponential one thanks one plus uh right +right h plus Lambda delta + + align:start position:0% +right h plus Lambda delta + + + align:start position:0% +right h plus Lambda delta +T plus this is the exponential series + + align:start position:0% +T plus this is the exponential series + + + align:start position:0% +T plus this is the exponential series +there only two Series in this world that + + align:start position:0% +there only two Series in this world that + + + align:start position:0% +there only two Series in this world that +are worth knowing really that's + + align:start position:0% +are worth knowing really that's + + + align:start position:0% +are worth knowing really that's +literally true you you calculus you + + align:start position:0% +literally true you you calculus you + + + align:start position:0% +literally true you you calculus you +study all these infinite series there + + align:start position:0% +study all these infinite series there + + + align:start position:0% +study all these infinite series there +are two that are important that are + + align:start position:0% +are two that are important that are + + + align:start position:0% +are two that are important that are +worth remembering long after calculus + + align:start position:0% +worth remembering long after calculus + + + align:start position:0% +worth remembering long after calculus +and x e to the e to the x e to the + + align:start position:0% +and x e to the e to the x e to the + + + align:start position:0% +and x e to the e to the x e to the +whatever is one of them okay what's the + + align:start position:0% +whatever is one of them okay what's the + + + align:start position:0% +whatever is one of them okay what's the +next + + align:start position:0% +next + + + align:start position:0% +next +term over two Lambda delta T squar over + + align:start position:0% +term over two Lambda delta T squar over + + + align:start position:0% +term over two Lambda delta T squar over +two and then there's a cube guy and and + + align:start position:0% +two and then there's a cube guy and and + + + align:start position:0% +two and then there's a cube guy and and +if you don't mind telling me what's the + + align:start position:0% +if you don't mind telling me what's the + + + align:start position:0% +if you don't mind telling me what's the +denominator in that + + align:start position:0% +denominator in that + + + align:start position:0% +denominator in that +one it's 3 factorial 6 good and onwards + + align:start position:0% +one it's 3 factorial 6 good and onwards + + + align:start position:0% +one it's 3 factorial 6 good and onwards +okay so that's one of the series that + + align:start position:0% +okay so that's one of the series that + + + align:start position:0% +okay so that's one of the series that +everybody should know okay how are we + + align:start position:0% +everybody should know okay how are we + + + align:start position:0% +everybody should know okay how are we +going to deal with this + + align:start position:0% +going to deal with this + + + align:start position:0% +going to deal with this +guy how how we want to expand that so + + align:start position:0% +guy how how we want to expand that so + + + align:start position:0% +guy how how we want to expand that so +what am I what's my goal I want you to + + align:start position:0% +what am I what's my goal I want you to + + + align:start position:0% +what am I what's my goal I want you to +expand that in powers of Lambda delta T + + align:start position:0% +expand that in powers of Lambda delta T + + + align:start position:0% +expand that in powers of Lambda delta T +and compare with this and see how how + + align:start position:0% +and compare with this and see how how + + + align:start position:0% +and compare with this and see how how +you know where do they they aren't going + + align:start position:0% +you know where do they they aren't going + + + align:start position:0% +you know where do they they aren't going +to be equal right at some point they're + + align:start position:0% +to be equal right at some point they're + + + align:start position:0% +to be equal right at some point they're +going to be different but at least they + + align:start position:0% +going to be different but at least they + + + align:start position:0% +going to be different but at least they +should start out equal so how do you can + + align:start position:0% +should start out equal so how do you can + + + align:start position:0% +should start out equal so how do you can +you do this so here's the heart of + + align:start position:0% +you do this so here's the heart of + + + align:start position:0% +you do this so here's the heart of +problem seven what do I do how do I + + align:start position:0% +problem seven what do I do how do I + + + align:start position:0% +problem seven what do I do how do I +expand this in powers of delta + + align:start position:0% +expand this in powers of delta + + + align:start position:0% +expand this in powers of delta +T can I do you mind if I just this is + + align:start position:0% +T can I do you mind if I just this is + + + align:start position:0% +T can I do you mind if I just this is +just a number let me put it times times + + align:start position:0% +just a number let me put it times times + + + align:start position:0% +just a number let me put it times times +one over it so this is times 1 minus + + align:start position:0% +one over it so this is times 1 minus + + + align:start position:0% +one over it so this is times 1 minus +delta T / 2 Lambda inverse right I just + + align:start position:0% +delta T / 2 Lambda inverse right I just + + + align:start position:0% +delta T / 2 Lambda inverse right I just +bring that up as a number so it's it's + + align:start position:0% +bring that up as a number so it's it's + + + align:start position:0% +bring that up as a number so it's it's +this guy times one over this + + align:start position:0% +this guy times one over this + + + align:start position:0% +this guy times one over this +guy what do I do this is you know here's + + align:start position:0% +guy what do I do this is you know here's + + + align:start position:0% +guy what do I do this is you know here's +here's the moment when uh you know the + + align:start position:0% +here's the moment when uh you know the + + + align:start position:0% +here's the moment when uh you know the +math tools get + + align:start position:0% +math tools get + + + align:start position:0% +math tools get +used + + align:start position:0% +used + + + align:start position:0% +used +and I'm I'm well aware that you know + + align:start position:0% +and I'm I'm well aware that you know + + + align:start position:0% +and I'm I'm well aware that you know +it's like years since you did calculus + + align:start position:0% +it's like years since you did calculus + + + align:start position:0% +it's like years since you did calculus +or series or whatever and uh those tools + + align:start position:0% +or series or whatever and uh those tools + + + align:start position:0% +or series or whatever and uh those tools +get + + align:start position:0% +get + + + align:start position:0% +get +rusty and the point is that they are + + align:start position:0% +rusty and the point is that they are + + + align:start position:0% +rusty and the point is that they are +really genuine tools that that we can + + align:start position:0% +really genuine tools that that we can + + + align:start position:0% +really genuine tools that that we can +now use so what do you + + align:start position:0% +now use so what do you + + + align:start position:0% +now use so what do you +think what shall I this is the sort of + + align:start position:0% +think what shall I this is the sort of + + + align:start position:0% +think what shall I this is the sort of +like problem one this is the one coming + + align:start position:0% +like problem one this is the one coming + + + align:start position:0% +like problem one this is the one coming +from the denominator this is 1 over 1 - + + align:start position:0% +from the denominator this is 1 over 1 - + + + align:start position:0% +from the denominator this is 1 over 1 - +x you should so I have a 1 over 1 - x + + align:start position:0% +x you should so I have a 1 over 1 - x + + + align:start position:0% +x you should so I have a 1 over 1 - x +deal and what's the series for that I + + align:start position:0% +deal and what's the series for that I + + + align:start position:0% +deal and what's the series for that I +you know I said there were two series + + align:start position:0% +you know I said there were two series + + + align:start position:0% +you know I said there were two series +worth remembering and sure enough the + + align:start position:0% +worth remembering and sure enough the + + + align:start position:0% +worth remembering and sure enough the +exponential was one of them and now + + align:start position:0% +exponential was one of them and now + + + align:start position:0% +exponential was one of them and now +we're ready for the other one what's the + + align:start position:0% +we're ready for the other one what's the + + + align:start position:0% +we're ready for the other one what's the +series for that + + align:start position:0% +series for that + + + align:start position:0% +series for that +guy 1 + x Good + + align:start position:0% +guy 1 + x Good + + + align:start position:0% +guy 1 + x Good +Start + + align:start position:0% +Start + + + align:start position:0% +Start +plus + + align:start position:0% + + + + align:start position:0% + +plus x s right X2 + + align:start position:0% +plus x s right X2 + + + align:start position:0% +plus x s right X2 +plus X cub and so on real simple it's + + align:start position:0% +plus X cub and so on real simple it's + + + align:start position:0% +plus X cub and so on real simple it's +all the same stuff with no factorials + + align:start position:0% +all the same stuff with no factorials + + + align:start position:0% +all the same stuff with no factorials +those are the two series to to know + + align:start position:0% +those are the two series to to know + + + align:start position:0% +those are the two series to to know +the exponential series and the geometric + + align:start position:0% +the exponential series and the geometric + + + align:start position:0% +the exponential series and the geometric +Series right that's the geometric series + + align:start position:0% +Series right that's the geometric series + + + align:start position:0% +Series right that's the geometric series +okay so that's what I've got out of this + + align:start position:0% +okay so that's what I've got out of this + + + align:start position:0% +okay so that's what I've got out of this +stuff can I write it below I have 1 + + + align:start position:0% +stuff can I write it below I have 1 + + + + align:start position:0% +stuff can I write it below I have 1 + +Delta t/ 2 Lambda can I get I let me + + align:start position:0% +Delta t/ 2 Lambda can I get I let me + + + align:start position:0% +Delta t/ 2 Lambda can I get I let me +just call that X for the moment Delta t/ + + align:start position:0% +just call that X for the moment Delta t/ + + + align:start position:0% +just call that X for the moment Delta t/ +2 Lambda is my x 1 + x and this is 1 + + align:start position:0% +2 Lambda is my x 1 + x and this is 1 + + + align:start position:0% +2 Lambda is my x 1 + x and this is 1 +over 1 - x which you just told me is 1 + + + align:start position:0% +over 1 - x which you just told me is 1 + + + + align:start position:0% +over 1 - x which you just told me is 1 + +x + x^2 plus X cub and so + + align:start position:0% +x + x^2 plus X cub and so + + + align:start position:0% +x + x^2 plus X cub and so +on and now I I got to do that + + align:start position:0% +on and now I I got to do that + + + align:start position:0% +on and now I I got to do that +multiplication okay X is remember this + + align:start position:0% +multiplication okay X is remember this + + + align:start position:0% +multiplication okay X is remember this +is X this is this is my X I'm just to + + align:start position:0% +is X this is this is my X I'm just to + + + align:start position:0% +is X this is this is my X I'm just to +save space can you multiply those + + align:start position:0% +save space can you multiply those + + + align:start position:0% +save space can you multiply those +guys so that's 1+ x times this lot of + + align:start position:0% +guys so that's 1+ x times this lot of + + + align:start position:0% +guys so that's 1+ x times this lot of +stuff here what do I have all together + + align:start position:0% +stuff here what do I have all together + + + align:start position:0% +stuff here what do I have all together +well the one what's the next + + align:start position:0% +well the one what's the next + + + align:start position:0% +well the one what's the next +term 2 X's everybody spots the two x's + + align:start position:0% +term 2 X's everybody spots the two x's + + + align:start position:0% +term 2 X's everybody spots the two x's +there + + align:start position:0% +there + + + align:start position:0% +there +and then the next + + align:start position:0% + + + + align:start position:0% + +term you have to get these terms right + + align:start position:0% +term you have to get these terms right + + + align:start position:0% +term you have to get these terms right +because we plan to compare with this guy + + align:start position:0% +because we plan to compare with this guy + + + align:start position:0% +because we plan to compare with this guy +and see how many we get how many X squs + + align:start position:0% +and see how many we get how many X squs + + + align:start position:0% +and see how many we get how many X squs +are in there is it two looks like two 2 + + align:start position:0% +are in there is it two looks like two 2 + + + align:start position:0% +are in there is it two looks like two 2 +X2 and 2 x cubes and so on yeah that + + align:start position:0% +X2 and 2 x cubes and so on yeah that + + + align:start position:0% +X2 and 2 x cubes and so on yeah that +that looks right okay now I'm I'm ready + + align:start position:0% +that looks right okay now I'm I'm ready + + + align:start position:0% +that looks right okay now I'm I'm ready +what am I ready + + align:start position:0% +what am I ready + + + align:start position:0% +what am I ready +for I'm ready to say what x is X is this + + align:start position:0% +for I'm ready to say what x is X is this + + + align:start position:0% +for I'm ready to say what x is X is this +delta T over 2 Lambda so what is it what + + align:start position:0% +delta T over 2 Lambda so what is it what + + + align:start position:0% +delta T over 2 Lambda so what is it what +have I got here one what is this guy now + + align:start position:0% +have I got here one what is this guy now + + + align:start position:0% +have I got here one what is this guy now +2 X's + + align:start position:0% +2 X's + + + align:start position:0% +2 X's +is delta T + + align:start position:0% +is delta T + + + align:start position:0% +is delta T +Lambda is this good yes right we're + + align:start position:0% +Lambda is this good yes right we're + + + align:start position:0% +Lambda is this good yes right we're +pleased because the 2x is the two of + + align:start position:0% +pleased because the 2x is the two of + + + align:start position:0% +pleased because the 2x is the two of +these is delta T Lambda and that's what + + align:start position:0% +these is delta T Lambda and that's what + + + align:start position:0% +these is delta T Lambda and that's what +we wanted to match absolutely delta T + + align:start position:0% +we wanted to match absolutely delta T + + + align:start position:0% +we wanted to match absolutely delta T +Lambda or Lambda delta T now let's keep + + align:start position:0% +Lambda or Lambda delta T now let's keep + + + align:start position:0% +Lambda or Lambda delta T now let's keep +going by the way if this first term + + align:start position:0% +going by the way if this first term + + + align:start position:0% +going by the way if this first term +hadn't matched we would be extremely + + align:start position:0% +hadn't matched we would be extremely + + + align:start position:0% +hadn't matched we would be extremely +surprised right because the the that + + align:start position:0% +surprised right because the the that + + + align:start position:0% +surprised right because the the that +first matching is only saying that my + + align:start position:0% +first matching is only saying that my + + + align:start position:0% +first matching is only saying that my +difference equation is like consistent + + align:start position:0% +difference equation is like consistent + + + align:start position:0% +difference equation is like consistent +it's a reasonable + + align:start position:0% +it's a reasonable + + + align:start position:0% +it's a reasonable +reasonable creation out out of the + + align:start position:0% +reasonable creation out out of the + + + align:start position:0% +reasonable creation out out of the +differential equation and we knew that + + align:start position:0% +differential equation and we knew that + + + align:start position:0% +differential equation and we knew that +the question is how much further we + + align:start position:0% +the question is how much further we + + + align:start position:0% +the question is how much further we +going to get Oiler will not get any + + align:start position:0% +going to get Oiler will not get any + + + align:start position:0% +going to get Oiler will not get any +further with Oiler the next ones will + + align:start position:0% +further with Oiler the next ones will + + + align:start position:0% +further with Oiler the next ones will +fail but I think with trapezoid the next + + align:start position:0% +fail but I think with trapezoid the next + + + align:start position:0% +fail but I think with trapezoid the next +ones are going to work does it + + align:start position:0% +ones are going to work does it + + + align:start position:0% +ones are going to work does it +work you're all you're like we're + + align:start position:0% +work you're all you're like we're + + + align:start position:0% +work you're all you're like we're +holding our Breath Right two now I'm + + align:start position:0% +holding our Breath Right two now I'm + + + align:start position:0% +holding our Breath Right two now I'm +going to put in X squar and see about + + align:start position:0% +going to put in X squar and see about + + + align:start position:0% +going to put in X squar and see about +this term X is + + align:start position:0% +this term X is + + + align:start position:0% +this term X is +what x is this guy Delta t/ 2 + + align:start position:0% +what x is this guy Delta t/ 2 + + + align:start position:0% +what x is this guy Delta t/ 2 +Lambda delta T Lambda over 2^ 2ar and + + align:start position:0% +Lambda delta T Lambda over 2^ 2ar and + + + align:start position:0% +Lambda delta T Lambda over 2^ 2ar and +now you get the the + + align:start position:0% +now you get the the + + + align:start position:0% +now you get the the +fun because you're going to compare this + + align:start position:0% +fun because you're going to compare this + + + align:start position:0% +fun because you're going to compare this +term with + + align:start position:0% +term with + + + align:start position:0% +term with +what with this + + align:start position:0% + + + + align:start position:0% + +term and are they the + + align:start position:0% +term and are they the + + + align:start position:0% +term and are they the +same yes yes so that's that's the way + + align:start position:0% +same yes yes so that's that's the way + + + align:start position:0% +same yes yes so that's that's the way +you see that you got the extra accuracy + + align:start position:0% +you see that you got the extra accuracy + + + align:start position:0% +you see that you got the extra accuracy +which Oiler did not give you but so that + + align:start position:0% +which Oiler did not give you but so that + + + align:start position:0% +which Oiler did not give you but so that +that's why the trapezoidal rule is a + + align:start position:0% +that's why the trapezoidal rule is a + + + align:start position:0% +that's why the trapezoidal rule is a +second order accurate method okay that + + align:start position:0% +second order accurate method okay that + + + align:start position:0% +second order accurate method okay that +for + + align:start position:0% +for + + + align:start position:0% +for +uh you may say like that I went + + align:start position:0% +uh you may say like that I went + + + align:start position:0% +uh you may say like that I went +overboard to say all that you know you + + align:start position:0% +overboard to say all that you know you + + + align:start position:0% +overboard to say all that you know you +you may say I didn't ask that question + + align:start position:0% +you may say I didn't ask that question + + + align:start position:0% +you may say I didn't ask that question +but it's the right question to ask about + + align:start position:0% +but it's the right question to ask about + + + align:start position:0% +but it's the right question to ask about +order of accuracy and it's what problem + + align:start position:0% +order of accuracy and it's what problem + + + align:start position:0% +order of accuracy and it's what problem +seven was intending to bring to to maybe + + align:start position:0% +seven was intending to bring to to maybe + + + align:start position:0% +seven was intending to bring to to maybe +I called it h in problem 7 rather than + + align:start position:0% +I called it h in problem 7 rather than + + + align:start position:0% +I called it h in problem 7 rather than +uh X + + align:start position:0% + + + + align:start position:0% + +here + + align:start position:0% +here + + + align:start position:0% +here +well oh gosh I realize I've still have + + align:start position:0% +well oh gosh I realize I've still have + + + align:start position:0% +well oh gosh I realize I've still have +you I'm supposed to come back to this + + align:start position:0% +you I'm supposed to come back to this + + + align:start position:0% +you I'm supposed to come back to this +this one but some people might have + + align:start position:0% +this one but some people might have + + + align:start position:0% +this one but some people might have +other problems that they're interested + + align:start position:0% +other problems that they're interested + + + align:start position:0% +other problems that they're interested +in let let me because time is pushing + + align:start position:0% +in let let me because time is pushing + + + align:start position:0% +in let let me because time is pushing +along uh and the solution of this one + + align:start position:0% +along uh and the solution of this one + + + align:start position:0% +along uh and the solution of this one +will post let me at least offer the + + align:start position:0% +will post let me at least offer the + + + align:start position:0% +will post let me at least offer the +possibility to ask me about something + + align:start position:0% +possibility to ask me about something + + + align:start position:0% +possibility to ask me about something +completely not six or seven here but + + align:start position:0% +completely not six or seven here but + + + align:start position:0% +completely not six or seven here but +something entirely different like what's + + align:start position:0% +something entirely different like what's + + + align:start position:0% +something entirely different like what's +the first question on the quiz or + + align:start position:0% +the first question on the quiz or + + + align:start position:0% +the first question on the quiz or +anything and that let me say I'm a + + align:start position:0% +anything and that let me say I'm a + + + align:start position:0% +anything and that let me say I'm a +uh I'll hope to know by Tuesday + + align:start position:0% +uh I'll hope to know by Tuesday + + + align:start position:0% +uh I'll hope to know by Tuesday +uh I I it's it's I love to to teach and + + align:start position:0% +uh I I it's it's I love to to teach and + + + align:start position:0% +uh I I it's it's I love to to teach and +but making up exams is serious work + + align:start position:0% +but making up exams is serious work + + + align:start position:0% +but making up exams is serious work +anyway uh uh let me move up open a board + + align:start position:0% +anyway uh uh let me move up open a board + + + align:start position:0% +anyway uh uh let me move up open a board +and O open to another question of of any + + align:start position:0% +and O open to another question of of any + + + align:start position:0% +and O open to another question of of any +sort any place chapter one chapter two + + align:start position:0% +sort any place chapter one chapter two + + + align:start position:0% +sort any place chapter one chapter two +whatever is there + + align:start position:0% +whatever is there + + + align:start position:0% +whatever is there +anything so you I know that you're in + + align:start position:0% +anything so you I know that you're in + + + align:start position:0% +anything so you I know that you're in +the middle of this homework uh so I can + + align:start position:0% +the middle of this homework uh so I can + + + align:start position:0% +the middle of this homework uh so I can +say a little more here about the about + + align:start position:0% +say a little more here about the about + + + align:start position:0% +say a little more here about the about +the uh that number six if you if you + + align:start position:0% +the uh that number six if you if you + + + align:start position:0% +the uh that number six if you if you +want but I wanted to allow + + align:start position:0% + + + + align:start position:0% + +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +on uh the A and the from today from + + align:start position:0% +on uh the A and the from today from + + + align:start position:0% +on uh the A and the from today from +today's lecture this was the incidence + + align:start position:0% +today's lecture this was the incidence + + + align:start position:0% +today's lecture this was the incidence +Matrix okay and this was the a transpose + + align:start position:0% +Matrix okay and this was the a transpose + + + align:start position:0% +Matrix okay and this was the a transpose +a that's probably still on the board + + align:start position:0% +a that's probably still on the board + + + align:start position:0% +a that's probably still on the board +somewhere + + align:start position:0% + + + + align:start position:0% + +yeah yeah so this is what uh so this is + + align:start position:0% +yeah yeah so this is what uh so this is + + + align:start position:0% +yeah yeah so this is what uh so this is +the a which you should take in and and + + align:start position:0% +the a which you should take in and and + + + align:start position:0% +the a which you should take in and and +be able to create if I gave you the + + align:start position:0% +be able to create if I gave you the + + + align:start position:0% +be able to create if I gave you the +graph and this is the a transpose a so + + align:start position:0% +graph and this is the a transpose a so + + + align:start position:0% +graph and this is the a transpose a so +so it's through today's lecture right + + align:start position:0% +so it's through today's lecture right + + + align:start position:0% +so it's through today's lecture right +yeah next next lecture I'll be talking + + align:start position:0% +yeah next next lecture I'll be talking + + + align:start position:0% +yeah next next lecture I'll be talking +about the a transpose by itself which + + align:start position:0% +about the a transpose by itself which + + + align:start position:0% +about the a transpose by itself which +involves kof's current law it's + + align:start position:0% +involves kof's current law it's + + + align:start position:0% +involves kof's current law it's +beautiful beautiful a transpose W equals + + align:start position:0% +beautiful beautiful a transpose W equals + + + align:start position:0% +beautiful beautiful a transpose W equals +z but + + align:start position:0% +z but + + + align:start position:0% +z but +I think this part was straightforward + + align:start position:0% +I think this part was straightforward + + + align:start position:0% +I think this part was straightforward +enough to to be able to add this to our + + align:start position:0% +enough to to be able to add this to our + + + align:start position:0% +enough to to be able to add this to our +list + + align:start position:0% +list + + + align:start position:0% +list +of uh problems where which fit the + + align:start position:0% +of uh problems where which fit the + + + align:start position:0% +of uh problems where which fit the +framework yeah yeah so that's that's + + align:start position:0% +framework yeah yeah so that's that's + + + align:start position:0% +framework yeah yeah so that's that's +what that was about that doesn't mean + + align:start position:0% +what that was about that doesn't mean + + + align:start position:0% +what that was about that doesn't mean +that this will be on but it could be + + align:start position:0% +that this will be on but it could be + + + align:start position:0% +that this will be on but it could be +right okay what else you guys are + + align:start position:0% +right okay what else you guys are + + + align:start position:0% +right okay what else you guys are +patient to come on yeah thanks that gec + + align:start position:0% + + + + align:start position:0% + +form + + align:start position:0% +form + + + align:start position:0% +form +it's only valid when X is less than one + + align:start position:0% +it's only valid when X is less than one + + + align:start position:0% +it's only valid when X is less than one +yeah that's uh so that's now the math + + align:start position:0% +yeah that's uh so that's now the math + + + align:start position:0% +yeah that's uh so that's now the math +point that this expansion for e to the x + + align:start position:0% +point that this expansion for e to the x + + + align:start position:0% +point that this expansion for e to the x +is valid all X's because you're dividing + + align:start position:0% +is valid all X's because you're dividing + + + align:start position:0% +is valid all X's because you're dividing +by these bigger and bigger numbers but + + align:start position:0% +by these bigger and bigger numbers but + + + align:start position:0% +by these bigger and bigger numbers but +this one is only valid up to xal 1 at + + align:start position:0% +this one is only valid up to xal 1 at + + + align:start position:0% +this one is only valid up to xal 1 at +xal 1 we're getting 1 + 1 + 1 and we're + + align:start position:0% +xal 1 we're getting 1 + 1 + 1 and we're + + + align:start position:0% +xal 1 we're getting 1 + 1 + 1 and we're +getting 1 over 1 - one sort of infinity + + align:start position:0% +getting 1 over 1 - one sort of infinity + + + align:start position:0% +getting 1 over 1 - one sort of infinity +matches Infinity but then if x goes up + + align:start position:0% +matches Infinity but then if x goes up + + + align:start position:0% +matches Infinity but then if x goes up +to + + align:start position:0% +to + + + align:start position:0% +to +two yeah what happens if x is + + align:start position:0% +two yeah what happens if x is + + + align:start position:0% +two yeah what happens if x is +two it's it's sort of not good but you + + align:start position:0% +two it's it's sort of not good but you + + + align:start position:0% +two it's it's sort of not good but you +know mathematics is it's never + + align:start position:0% +know mathematics is it's never + + + align:start position:0% +know mathematics is it's never +completely crazy right if x is two what + + align:start position:0% +completely crazy right if x is two what + + + align:start position:0% +completely crazy right if x is two what +does this say what have I got on the + + align:start position:0% +does this say what have I got on the + + + align:start position:0% +does this say what have I got on the +left hand + + align:start position:0% + + + + align:start position:0% + +side-1 and what have I got on the right + + align:start position:0% +side-1 and what have I got on the right + + + align:start position:0% +side-1 and what have I got on the right +hand + + align:start position:0% +hand + + + align:start position:0% +hand +side 1 + 2 + 4 + + + align:start position:0% +side 1 + 2 + 4 + + + + align:start position:0% +side 1 + 2 + 4 + +8 I should not allow this to be + + align:start position:0% +8 I should not allow this to be + + + align:start position:0% +8 I should not allow this to be +videotaped but uh that that actually not + + align:start position:0% +videotaped but uh that that actually not + + + align:start position:0% +videotaped but uh that that actually not +so completely crazy in some in some + + align:start position:0% +so completely crazy in some in some + + + align:start position:0% +so completely crazy in some in some +nutty way you know that could still make + + align:start position:0% +nutty way you know that could still make + + + align:start position:0% +nutty way you know that could still make +some + + align:start position:0% +some + + + align:start position:0% +some +sense I won't that certainly will not be + + align:start position:0% +sense I won't that certainly will not be + + + align:start position:0% +sense I won't that certainly will not be +on the so you're right that X should be + + align:start position:0% +on the so you're right that X should be + + + align:start position:0% +on the so you're right that X should be +less than one and of course uh it will + + align:start position:0% +less than one and of course uh it will + + + align:start position:0% +less than one and of course uh it will +be here because I'm looking at little + + align:start position:0% +be here because I'm looking at little + + + align:start position:0% +be here because I'm looking at little +Delta T's little so my delta T my X was + + align:start position:0% +Delta T's little so my delta T my X was + + + align:start position:0% +Delta T's little so my delta T my X was +this thing and my delta T the time step + + align:start position:0% +this thing and my delta T the time step + + + align:start position:0% +this thing and my delta T the time step +was small and and somehow that tells me + + align:start position:0% +was small and and somehow that tells me + + + align:start position:0% +was small and and somehow that tells me +actually this this is a a good + + align:start position:0% +actually this this is a a good + + + align:start position:0% +actually this this is a a good +indication it gives me the units that + + align:start position:0% +indication it gives me the units that + + + align:start position:0% +indication it gives me the units that +stability and things going right will + + align:start position:0% +stability and things going right will + + + align:start position:0% +stability and things going right will +depend on Lambda delta T will depend on + + align:start position:0% +depend on Lambda delta T will depend on + + + align:start position:0% +depend on Lambda delta T will depend on +Lambda delta T that's the key parameter + + align:start position:0% +Lambda delta T that's the key parameter + + + align:start position:0% +Lambda delta T that's the key parameter +there that's that's like the + + align:start position:0% +there that's that's like the + + + align:start position:0% +there that's that's like the +dimensionless parameter uh that that we + + align:start position:0% +dimensionless parameter uh that that we + + + align:start position:0% +dimensionless parameter uh that that we +or Lambda delta T over 2 or whatever but + + align:start position:0% +or Lambda delta T over 2 or whatever but + + + align:start position:0% +or Lambda delta T over 2 or whatever but +Lambda delta T is the key and and and + + align:start position:0% +Lambda delta T is the key and and and + + + align:start position:0% +Lambda delta T is the key and and and +highly important key it tells us that as + + align:start position:0% +highly important key it tells us that as + + + align:start position:0% +highly important key it tells us that as +Lambda gets bigger as the Matrix has + + align:start position:0% +Lambda gets bigger as the Matrix has + + + align:start position:0% +Lambda gets bigger as the Matrix has +bigger igen values delta T has got to + + align:start position:0% +bigger igen values delta T has got to + + + align:start position:0% +bigger igen values delta T has got to +get + + align:start position:0% +get + + + align:start position:0% +get +smaller and and I mentioned stiff + + align:start position:0% +smaller and and I mentioned stiff + + + align:start position:0% +smaller and and I mentioned stiff +equations stiff equations are equations + + align:start position:0% +equations stiff equations are equations + + + align:start position:0% +equations stiff equations are equations +where the I values Lambda are are are + + align:start position:0% +where the I values Lambda are are are + + + align:start position:0% +where the I values Lambda are are are +out of scale you know you might have two + + align:start position:0% +out of scale you know you might have two + + + align:start position:0% +out of scale you know you might have two +IG values one of size one and the other + + align:start position:0% +IG values one of size one and the other + + + align:start position:0% +IG values one of size one and the other +of size 10 the 4th because you've got + + align:start position:0% +of size 10 the 4th because you've got + + + align:start position:0% +of size 10 the 4th because you've got +two physical processes going on at the + + align:start position:0% +two physical processes going on at the + + + align:start position:0% +two physical processes going on at the +same time + + align:start position:0% +same time + + + align:start position:0% +same time +time and those equations are tough + + align:start position:0% +time and those equations are tough + + + align:start position:0% +time and those equations are tough +because that 10 the fourth guy is + + align:start position:0% +because that 10 the fourth guy is + + + align:start position:0% +because that 10 the fourth guy is +forcing your your delta T to be really + + align:start position:0% +forcing your your delta T to be really + + + align:start position:0% +forcing your your delta T to be really +small whereas the the action might the + + align:start position:0% +small whereas the the action might the + + + align:start position:0% +small whereas the the action might the +true real solution might be controlled + + align:start position:0% +true real solution might be controlled + + + align:start position:0% +true real solution might be controlled +by the Lambda equal one guy so to follow + + align:start position:0% +by the Lambda equal one guy so to follow + + + align:start position:0% +by the Lambda equal one guy so to follow +this slow Evolution you're having to + + align:start position:0% +this slow Evolution you're having to + + + align:start position:0% +this slow Evolution you're having to +take very small steps because on top of + + align:start position:0% +take very small steps because on top of + + + align:start position:0% +take very small steps because on top of +that slow Evolution with the Lambda + + align:start position:0% +that slow Evolution with the Lambda + + + align:start position:0% +that slow Evolution with the Lambda +equal 1 there's some very fast Evolution + + align:start position:0% +equal 1 there's some very fast Evolution + + + align:start position:0% +equal 1 there's some very fast Evolution +maybe with Lambda equal minus 10 th000 + + align:start position:0% +maybe with Lambda equal minus 10 th000 + + + align:start position:0% +maybe with Lambda equal minus 10 th000 +yeah so that uh there's there's a lot uh + + align:start position:0% +yeah so that uh there's there's a lot uh + + + align:start position:0% +yeah so that uh there's there's a lot uh +happened here and and you always you + + align:start position:0% +happened here and and you always you + + + align:start position:0% +happened here and and you always you +have to think okay is there some way + + align:start position:0% +have to think okay is there some way + + + align:start position:0% +have to think okay is there some way +around that box and uh because forward + + align:start position:0% +around that box and uh because forward + + + align:start position:0% +around that box and uh because forward +Oiler would not get you through yeah + + align:start position:0% +Oiler would not get you through yeah + + + align:start position:0% +Oiler would not get you through yeah +okay thanks for that question you got + + align:start position:0% +okay thanks for that question you got + + + align:start position:0% +okay thanks for that question you got +another one okay so then if you're you + + align:start position:0% +another one okay so then if you're you + + + align:start position:0% +another one okay so then if you're you +weren using + + align:start position:0% +weren using + + + align:start position:0% +weren using +would uh if you weren't using small + + align:start position:0% +would uh if you weren't using small + + + align:start position:0% +would uh if you weren't using small +enough time steps okay + + align:start position:0% +enough time steps okay + + + align:start position:0% +enough time steps okay +for trapezoidal let's say I mean that + + align:start position:0% +for trapezoidal let's say I mean that + + + align:start position:0% +for trapezoidal let's say I mean that +expansion wouldn't hold if you were + + align:start position:0% +expansion wouldn't hold if you were + + + align:start position:0% +expansion wouldn't hold if you were +using a land well the expansion is + + align:start position:0% +using a land well the expansion is + + + align:start position:0% +using a land well the expansion is +really intended for small delta T yeah + + align:start position:0% +really intended for small delta T yeah + + + align:start position:0% +really intended for small delta T yeah +it's not intended I'm not you you see I + + align:start position:0% +it's not intended I'm not you you see I + + + align:start position:0% +it's not intended I'm not you you see I +never added up the whole series I just + + align:start position:0% +never added up the whole series I just + + + align:start position:0% +never added up the whole series I just +compared a couple of terms to see how + + align:start position:0% +compared a couple of terms to see how + + + align:start position:0% +compared a couple of terms to see how +how am I doing and they I got the extra + + align:start position:0% +how am I doing and they I got the extra + + + align:start position:0% +how am I doing and they I got the extra +term to match from trapezoidal that I + + align:start position:0% +term to match from trapezoidal that I + + + align:start position:0% +term to match from trapezoidal that I +didn't get from Oiler uh yeah so what + + align:start position:0% +didn't get from Oiler uh yeah so what + + + align:start position:0% +didn't get from Oiler uh yeah so what +what's to say if if you took Del Del to + + align:start position:0% +what's to say if if you took Del Del to + + + align:start position:0% +what's to say if if you took Del Del to +T too big what would happen in the + + align:start position:0% +T too big what would happen in the + + + align:start position:0% +T too big what would happen in the +trapezoidal + + align:start position:0% +trapezoidal + + + align:start position:0% +trapezoidal +method well you would stay on the circle + + align:start position:0% +method well you would stay on the circle + + + align:start position:0% +method well you would stay on the circle +cuz because the absolute value of this + + align:start position:0% +cuz because the absolute value of this + + + align:start position:0% +cuz because the absolute value of this +thing is truly one even if Lambda is + + align:start position:0% +thing is truly one even if Lambda is + + + align:start position:0% +thing is truly one even if Lambda is +enormous and delta T is way too big we + + align:start position:0% +enormous and delta T is way too big we + + + align:start position:0% +enormous and delta T is way too big we +still had we still had complex + + align:start position:0% +still had we still had complex + + + align:start position:0% +still had we still had complex +conjugates and their ratio was one so we + + align:start position:0% +conjugates and their ratio was one so we + + + align:start position:0% +conjugates and their ratio was one so we +would not leave The Circle at least in + + align:start position:0% +would not leave The Circle at least in + + + align:start position:0% +would not leave The Circle at least in +perfect arithmetic as everybody says you + + align:start position:0% +perfect arithmetic as everybody says you + + + align:start position:0% +perfect arithmetic as everybody says you +know if we didn't make any round off air + + align:start position:0% +know if we didn't make any round off air + + + align:start position:0% +know if we didn't make any round off air +we would not leave the circle but boy + + align:start position:0% +we would not leave the circle but boy + + + align:start position:0% +we would not leave the circle but boy +would we skip all over the place on that + + align:start position:0% +would we skip all over the place on that + + + align:start position:0% +would we skip all over the place on that +Circle so if we took delta T too big we + + align:start position:0% +Circle so if we took delta T too big we + + + align:start position:0% +Circle so if we took delta T too big we +would be completely inaccurate we + + align:start position:0% +would be completely inaccurate we + + + align:start position:0% +would be completely inaccurate we +wouldn't be unstable for trapezoidal + + align:start position:0% +wouldn't be unstable for trapezoidal + + + align:start position:0% +wouldn't be unstable for trapezoidal +because it would stay on the circle but + + align:start position:0% +because it would stay on the circle but + + + align:start position:0% +because it would stay on the circle but +it would be way the phase would be + + align:start position:0% +it would be way the phase would be + + + align:start position:0% +it would be way the phase would be +completely wrong yeah yeah so it' be a + + align:start position:0% +completely wrong yeah yeah so it' be a + + + align:start position:0% +completely wrong yeah yeah so it' be a +complex number of absolute value one but + + align:start position:0% +complex number of absolute value one but + + + align:start position:0% +complex number of absolute value one but +it would not be close to the + + align:start position:0% +it would not be close to the + + + align:start position:0% +it would not be close to the +exact uh growth factor + + align:start position:0% +exact uh growth factor + + + align:start position:0% +exact uh growth factor +yeah well so many things to to say you + + align:start position:0% +yeah well so many things to to say you + + + align:start position:0% +yeah well so many things to to say you +know I realize that uh the course moves + + align:start position:0% +know I realize that uh the course moves + + + align:start position:0% +know I realize that uh the course moves +along pretty quickly but uh this topic + + align:start position:0% +along pretty quickly but uh this topic + + + align:start position:0% +along pretty quickly but uh this topic +of numerical methods for differential + + align:start position:0% +of numerical methods for differential + + + align:start position:0% +of numerical methods for differential +equations that that's a core part of + + align:start position:0% +equations that that's a core part of + + + align:start position:0% +equations that that's a core part of +18086 so I'm like anticipating here in + + align:start position:0% +18086 so I'm like anticipating here in + + + align:start position:0% +18086 so I'm like anticipating here in +just two a couple of days what really + + align:start position:0% +just two a couple of days what really + + + align:start position:0% +just two a couple of days what really +takes longer is the stability and the + + align:start position:0% +takes longer is the stability and the + + + align:start position:0% +takes longer is the stability and the +accuracy and the and the best choices + + align:start position:0% +accuracy and the and the best choices + + + align:start position:0% +accuracy and the and the best choices +for time dep time dependent problems + + align:start position:0% +for time dep time dependent problems + + + align:start position:0% +for time dep time dependent problems +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +yeah okay always good questions anything + + align:start position:0% +yeah okay always good questions anything + + + align:start position:0% +yeah okay always good questions anything +else just on your mind of any sort yes + + align:start position:0% +else just on your mind of any sort yes + + + align:start position:0% +else just on your mind of any sort yes +thanks the textbook page 114 114 yeah + + align:start position:0% +thanks the textbook page 114 114 yeah + + + align:start position:0% +thanks the textbook page 114 114 yeah +there is a + + align:start position:0% +there is a + + + align:start position:0% +there is a +2.7 + + align:start position:0% + + + + align:start position:0% + +okay 114 figure + + align:start position:0% +okay 114 figure + + + align:start position:0% +okay 114 figure +2.7 oh yes okay + + align:start position:0% +2.7 oh yes okay + + + align:start position:0% +2.7 oh yes okay +oh + + align:start position:0% +oh + + + align:start position:0% +oh +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +this so let's see which so that that has + + align:start position:0% +this so let's see which so that that has + + + align:start position:0% +this so let's see which so that that has +a bunch of figures uh so that in order + + align:start position:0% +a bunch of figures uh so that in order + + + align:start position:0% +a bunch of figures uh so that in order +to say for everybody who's not looking + + align:start position:0% +to say for everybody who's not looking + + + align:start position:0% +to say for everybody who's not looking +at the book those figures are about the + + align:start position:0% +at the book those figures are about the + + + align:start position:0% +at the book those figures are about the +problem we've discussed here or the + + align:start position:0% +problem we've discussed here or the + + + align:start position:0% +problem we've discussed here or the +model problem where uh we're on a circle + + align:start position:0% +model problem where uh we're on a circle + + + align:start position:0% +model problem where uh we're on a circle +so do I have space to draw a circle well + + align:start position:0% +so do I have space to draw a circle well + + + align:start position:0% +so do I have space to draw a circle well +let me just make space here + + align:start position:0% +let me just make space here + + + align:start position:0% +let me just make space here +okay so page 114 has that model problem + + align:start position:0% +okay so page 114 has that model problem + + + align:start position:0% +okay so page 114 has that model problem +that we've drawn before this the exact + + align:start position:0% +that we've drawn before this the exact + + + align:start position:0% +that we've drawn before this the exact +solution here's the it's the phase plane + + align:start position:0% +solution here's the it's the phase plane + + + align:start position:0% +solution here's the it's the phase plane +there's U and there's U Prime and the U + + align:start position:0% +there's U and there's U Prime and the U + + + align:start position:0% +there's U and there's U Prime and the U +was cost T so the U Prime was minus sin + + align:start position:0% +was cost T so the U Prime was minus sin + + + align:start position:0% +was cost T so the U Prime was minus sin +T and we travel around the circle on the + + align:start position:0% +T and we travel around the circle on the + + + align:start position:0% +T and we travel around the circle on the +exact solution energy constant U ^2 + + align:start position:0% +exact solution energy constant U ^2 + + + align:start position:0% +exact solution energy constant U ^2 +stays one U ^2 plus u Prime squ stay 1 + + align:start position:0% +stays one U ^2 plus u Prime squ stay 1 + + + align:start position:0% +stays one U ^2 plus u Prime squ stay 1 +now which figure was it you wanted me + + align:start position:0% +now which figure was it you wanted me + + + align:start position:0% +now which figure was it you wanted me +to look at + + align:start position:0% +to look at + + + align:start position:0% +to look at +so of any of them um yeah okay that's + + align:start position:0% +so of any of them um yeah okay that's + + + align:start position:0% +so of any of them um yeah okay that's +fine uh let's see is trapezoidal on that + + align:start position:0% +fine uh let's see is trapezoidal on that + + + align:start position:0% +fine uh let's see is trapezoidal on that +one yeah trapezoidal was the first one + + align:start position:0% +one yeah trapezoidal was the first one + + + align:start position:0% +one yeah trapezoidal was the first one +okay so figure 26 shows the trapezoidal + + align:start position:0% +okay so figure 26 shows the trapezoidal + + + align:start position:0% +okay so figure 26 shows the trapezoidal +method moving around the circle so what + + align:start position:0% +method moving around the circle so what + + + align:start position:0% +method moving around the circle so what +happens yeah thanks it's a very suitable + + align:start position:0% +happens yeah thanks it's a very suitable + + + align:start position:0% +happens yeah thanks it's a very suitable +question okay + + align:start position:0% +question okay + + + align:start position:0% +question okay +and I took uh the in that figure I took + + align:start position:0% +and I took uh the in that figure I took + + + align:start position:0% +and I took uh the in that figure I took +the how long does it take for the exact + + align:start position:0% +the how long does it take for the exact + + + align:start position:0% +the how long does it take for the exact +solution to get exactly back where it + + align:start position:0% +solution to get exactly back where it + + + align:start position:0% +solution to get exactly back where it +started at t equal what do I come + + align:start position:0% +started at t equal what do I come + + + align:start position:0% +started at t equal what do I come +back 2 pi t equal to 2 pi I'm right back + + align:start position:0% +back 2 pi t equal to 2 pi I'm right back + + + align:start position:0% +back 2 pi t equal to 2 pi I'm right back +where I was right cosine has Period 2 pi + + align:start position:0% +where I was right cosine has Period 2 pi + + + align:start position:0% +where I was right cosine has Period 2 pi +okay now suppose I take two suppose a + + align:start position:0% +okay now suppose I take two suppose a + + + align:start position:0% +okay now suppose I take two suppose a +single step of size two Pi would be + + align:start position:0% +single step of size two Pi would be + + + align:start position:0% +single step of size two Pi would be +really uh ridiculous right I mean delta + + align:start position:0% +really uh ridiculous right I mean delta + + + align:start position:0% +really uh ridiculous right I mean delta +T I want to now delta T so let me take + + align:start position:0% +T I want to now delta T so let me take + + + align:start position:0% +T I want to now delta T so let me take +in that figure I took delta T to be 2 pi + + align:start position:0% +in that figure I took delta T to be 2 pi + + + align:start position:0% +in that figure I took delta T to be 2 pi +ided + + align:start position:0% +ided + + + align:start position:0% +ided +32 so I'm taking delta T to be the 2 pi + + align:start position:0% +32 so I'm taking delta T to be the 2 pi + + + align:start position:0% +32 so I'm taking delta T to be the 2 pi +that that would bring me all the way + + align:start position:0% +that that would bring me all the way + + + align:start position:0% +that that would bring me all the way +around but I'm taking dividing by 32 so + + align:start position:0% +around but I'm taking dividing by 32 so + + + align:start position:0% +around but I'm taking dividing by 32 so +what does that mean what what does the + + align:start position:0% +what does that mean what what does the + + + align:start position:0% +what does that mean what what does the +exact solution do at those steps 32 + + align:start position:0% +exact solution do at those steps 32 + + + align:start position:0% +exact solution do at those steps 32 +steps + + align:start position:0% +steps + + + align:start position:0% +steps +it goes on the Circle 32 equal steps 3 + + align:start position:0% +it goes on the Circle 32 equal steps 3 + + + align:start position:0% +it goes on the Circle 32 equal steps 3 +360 or 2 pi ID 32 radians every time + + align:start position:0% +360 or 2 pi ID 32 radians every time + + + align:start position:0% +360 or 2 pi ID 32 radians every time +comes back exactly there the exact + + align:start position:0% +comes back exactly there the exact + + + align:start position:0% +comes back exactly there the exact +solution and uh right where I + + align:start position:0% +solution and uh right where I + + + align:start position:0% +solution and uh right where I +started so it's like following the the a + + align:start position:0% +started so it's like following the the a + + + align:start position:0% +started so it's like following the the a +planet now I do it by finite + + align:start position:0% +planet now I do it by finite + + + align:start position:0% +planet now I do it by finite +differences and so now I'm going to + + align:start position:0% +differences and so now I'm going to + + + align:start position:0% +differences and so now I'm going to +follow the trapezoidal rule just what + + align:start position:0% +follow the trapezoidal rule just what + + + align:start position:0% +follow the trapezoidal rule just what +we've been talking about with that time + + align:start position:0% +we've been talking about with that time + + + align:start position:0% +we've been talking about with that time +step + + align:start position:0% +step + + + align:start position:0% +step +and with the equation everybody + + align:start position:0% +and with the equation everybody + + + align:start position:0% +and with the equation everybody +remembers the the equation was uu Prime + + align:start position:0% +remembers the the equation was uu Prime + + + align:start position:0% +remembers the the equation was uu Prime +equals do you remember what the Matrix + + align:start position:0% +equals do you remember what the Matrix + + + align:start position:0% +equals do you remember what the Matrix +was in that + + align:start position:0% +was in that + + + align:start position:0% +was in that +equation oh this is the derivative of it + + align:start position:0% +equation oh this is the derivative of it + + + align:start position:0% +equation oh this is the derivative of it +and this is u u Prime sorry to squeeze + + align:start position:0% +and this is u u Prime sorry to squeeze + + + align:start position:0% +and this is u u Prime sorry to squeeze +this in but what I'm U Prime is U + + align:start position:0% +this in but what I'm U Prime is U + + + align:start position:0% +this in but what I'm U Prime is U +prime uble prime is minus + + align:start position:0% +prime uble prime is minus + + + align:start position:0% +prime uble prime is minus +U now now we know why that Matrix was + + align:start position:0% +U now now we know why that Matrix was + + + align:start position:0% +U now now we know why that Matrix was +good right wh why is that that that's my + + align:start position:0% +good right wh why is that that that's my + + + align:start position:0% +good right wh why is that that that's my +Matrix a why is it + + align:start position:0% +Matrix a why is it + + + align:start position:0% +Matrix a why is it +good because it's exactly it + + align:start position:0% +good because it's exactly it + + + align:start position:0% +good because it's exactly it +fits a transposes minus a it's anti- + + align:start position:0% +fits a transposes minus a it's anti- + + + align:start position:0% +fits a transposes minus a it's anti- +symmetric keeps me right on the circle + + align:start position:0% +symmetric keeps me right on the circle + + + align:start position:0% +symmetric keeps me right on the circle +okay now trapezoidal method keeps me + + align:start position:0% +okay now trapezoidal method keeps me + + + align:start position:0% +okay now trapezoidal method keeps me +right on the Circle 32 steps and so the + + align:start position:0% +right on the Circle 32 steps and so the + + + align:start position:0% +right on the Circle 32 steps and so the +picture just shows where it goes after + + align:start position:0% +picture just shows where it goes after + + + align:start position:0% +picture just shows where it goes after + + align:start position:0% + + + align:start position:0% +steps and 32 32 does it come back + + align:start position:0% +steps and 32 32 does it come back + + + align:start position:0% +steps and 32 32 does it come back +there + + align:start position:0% +there + + + align:start position:0% +there +well not exactly right we don't expect + + align:start position:0% +well not exactly right we don't expect + + + align:start position:0% +well not exactly right we don't expect +the exact the finite difference solution + + align:start position:0% +the exact the finite difference solution + + + align:start position:0% +the exact the finite difference solution +to be exactly in sync with the cosine T + + align:start position:0% +to be exactly in sync with the cosine T + + + align:start position:0% +to be exactly in sync with the cosine T +the real one but it's really close I + + align:start position:0% +the real one but it's really close I + + + align:start position:0% +the real one but it's really close I +think in that figure you can your eye + + align:start position:0% +think in that figure you can your eye + + + align:start position:0% +think in that figure you can your eye +can see that that's sort of a double + + align:start position:0% +can see that that's sort of a double + + + align:start position:0% +can see that that's sort of a double +point there at 2 pi I I put a little + + align:start position:0% +point there at 2 pi I I put a little + + + align:start position:0% +point there at 2 pi I I put a little +arrow indicating small phase error it it + + align:start position:0% +arrow indicating small phase error it it + + + align:start position:0% +arrow indicating small phase error it it +misses by a little bit right it misses + + align:start position:0% +misses by a little bit right it misses + + + align:start position:0% +misses by a little bit right it misses +by a little bit and + + align:start position:0% +by a little bit and + + + align:start position:0% +by a little bit and +actually roughly what does it Miss + + align:start position:0% +actually roughly what does it Miss + + + align:start position:0% +actually roughly what does it Miss +by this is this was the point of the + + align:start position:0% +by this is this was the point of the + + + align:start position:0% +by this is this was the point of the +order of accuracy stuff what what + + align:start position:0% +order of accuracy stuff what what + + + align:start position:0% +order of accuracy stuff what what +roughly what size is the is that little + + align:start position:0% +roughly what size is the is that little + + + align:start position:0% +roughly what size is the is that little +error that's what we did over here the + + align:start position:0% +error that's what we did over here the + + + align:start position:0% +error that's what we did over here the +the the term that we got wrong was a + + align:start position:0% +the the term that we got wrong was a + + + align:start position:0% +the the term that we got wrong was a +delta T + + align:start position:0% +delta T + + + align:start position:0% +delta T +cubed at each + + align:start position:0% +cubed at each + + + align:start position:0% +cubed at each +step can I just tell you the answer the + + align:start position:0% +step can I just tell you the answer the + + + align:start position:0% +step can I just tell you the answer the +the error here is of size Delta Del T + + align:start position:0% +the error here is of size Delta Del T + + + align:start position:0% +the error here is of size Delta Del T +squar cuz over here we matched those + + align:start position:0% +squar cuz over here we matched those + + + align:start position:0% +squar cuz over here we matched those +series and we found the error was delta + + align:start position:0% +series and we found the error was delta + + + align:start position:0% +series and we found the error was delta +T cubed that's in a single step but now + + align:start position:0% +T cubed that's in a single step but now + + + align:start position:0% +T cubed that's in a single step but now +we've got like one over delta T steps + + align:start position:0% +we've got like one over delta T steps + + + align:start position:0% +we've got like one over delta T steps +you you see what I'm saying that if it + + align:start position:0% +you you see what I'm saying that if it + + + align:start position:0% +you you see what I'm saying that if it +was delt if the local if the error was + + align:start position:0% +was delt if the local if the error was + + + align:start position:0% +was delt if the local if the error was +delta T Cub per step and I have one over + + align:start position:0% +delta T Cub per step and I have one over + + + align:start position:0% +delta T Cub per step and I have one over +delta T + + align:start position:0% +delta T + + + align:start position:0% +delta T +steps to get somewhere or 2 pi over + + align:start position:0% +steps to get somewhere or 2 pi over + + + align:start position:0% +steps to get somewhere or 2 pi over +delta T or whatever uh then that gives + + align:start position:0% +delta T or whatever uh then that gives + + + align:start position:0% +delta T or whatever uh then that gives +me delta T so that that little error + + align:start position:0% +me delta T so that that little error + + + align:start position:0% +me delta T so that that little error +there is is my error of size delta T + + align:start position:0% +there is is my error of size delta T + + + align:start position:0% +there is is my error of size delta T +squar and that square tells me I've got + + align:start position:0% +squar and that square tells me I've got + + + align:start position:0% +squar and that square tells me I've got +a good method at least decent second + + align:start position:0% +a good method at least decent second + + + align:start position:0% +a good method at least decent second +order accurate and the trapezoidal rule + + align:start position:0% +order accurate and the trapezoidal rule + + + align:start position:0% +order accurate and the trapezoidal rule +is uh sort of the natural + + align:start position:0% + + + + align:start position:0% + +one well okay so that's a full hour + + align:start position:0% +one well okay so that's a full hour + + + align:start position:0% +one well okay so that's a full hour +mostly devoted to two or three things + + align:start position:0% +mostly devoted to two or three things + + + align:start position:0% +mostly devoted to two or three things +actually the I vectors came in into it + + align:start position:0% +actually the I vectors came in into it + + + align:start position:0% +actually the I vectors came in into it +and the the energy conservation came + + align:start position:0% +and the the energy conservation came + + + align:start position:0% +and the the energy conservation came +into it the stability matching series + + align:start position:0% +into it the stability matching series + + + align:start position:0% +into it the stability matching series +came into it and the + + align:start position:0% +came into it and the + + + align:start position:0% +came into it and the +picture okay so I'll see you Friday for + + align:start position:0% +picture okay so I'll see you Friday for + + + align:start position:0% +picture okay so I'll see you Friday for +more + + align:start position:0% +more + + + align:start position:0% +more +about uh these guys and then Monday + + align:start position:0% +about uh these guys and then Monday + + + align:start position:0% +about uh these guys and then Monday +evening + + align:start position:0% +evening + + + align:start position:0% +evening +please ask me everything you want to on + + align:start position:0% +please ask me everything you want to on + + + align:start position:0% +please ask me everything you want to on +Monday evening + + align:start position:0% +Monday evening + + + align:start position:0% +Monday evening +okay thank you \ No newline at end of file diff --git a/0kA91PvS3sk.txt b/0kA91PvS3sk.txt new file mode 100644 index 0000000000000000000000000000000000000000..502a446e5ef835c32319ea89b566c9985ae61503 --- /dev/null +++ b/0kA91PvS3sk.txt @@ -0,0 +1,8291 @@ +align:start position:0% + +all right why don't we get started today + + align:start position:0% +all right why don't we get started today + + + align:start position:0% +all right why don't we get started today +we're going to move on to finally the + + align:start position:0% +we're going to move on to finally the + + + align:start position:0% +we're going to move on to finally the +most realistic market structure we + + align:start position:0% +most realistic market structure we + + + align:start position:0% +most realistic market structure we +talked about perfectly competitive + + align:start position:0% +talked about perfectly competitive + + + align:start position:0% +talked about perfectly competitive +market so now that was a very useful + + align:start position:0% +market so now that was a very useful + + + align:start position:0% +market so now that was a very useful +extreme example to help us think about + + align:start position:0% +extreme example to help us think about + + + align:start position:0% +extreme example to help us think about +economic efficiency we then flipped over + + align:start position:0% +economic efficiency we then flipped over + + + align:start position:0% +economic efficiency we then flipped over +to talk about the somewhat more + + align:start position:0% +to talk about the somewhat more + + + align:start position:0% +to talk about the somewhat more +realistic case of monopoly but still + + align:start position:0% +realistic case of monopoly but still + + + align:start position:0% +realistic case of monopoly but still +very few markets have only one + + align:start position:0% +very few markets have only one + + + align:start position:0% +very few markets have only one +participant a true monopoly is rare in + + align:start position:0% +participant a true monopoly is rare in + + + align:start position:0% +participant a true monopoly is rare in +the private market what most markets are + + align:start position:0% +the private market what most markets are + + + align:start position:0% +the private market what most markets are +marked are by are probably more features + + align:start position:0% +marked are by are probably more features + + + align:start position:0% +marked are by are probably more features +of oligopoly which is a market with a + + align:start position:0% +of oligopoly which is a market with a + + + align:start position:0% +of oligopoly which is a market with a +small group of firms competing with each + + align:start position:0% +small group of firms competing with each + + + align:start position:0% +small group of firms competing with each +other but with barriers to entry that + + align:start position:0% +other but with barriers to entry that + + + align:start position:0% +other but with barriers to entry that +keep out an unlimited number of firms + + align:start position:0% +keep out an unlimited number of firms + + + align:start position:0% +keep out an unlimited number of firms +say about these as markets where there + + align:start position:0% +say about these as markets where there + + + align:start position:0% +say about these as markets where there +are some barriers to entry so firms just + + align:start position:0% +are some barriers to entry so firms just + + + align:start position:0% +are some barriers to entry so firms just +can't cautiously enter an exit like they + + align:start position:0% +can't cautiously enter an exit like they + + + align:start position:0% +can't cautiously enter an exit like they +could in our IBM Dell example but where + + align:start position:0% +could in our IBM Dell example but where + + + align:start position:0% +could in our IBM Dell example but where +there's small enough eros entry that a + + align:start position:0% +there's small enough eros entry that a + + + align:start position:0% +there's small enough eros entry that a +few firms have gotten in not just one so + + align:start position:0% +few firms have gotten in not just one so + + + align:start position:0% +few firms have gotten in not just one so +it's not a natural monopoly it's not + + align:start position:0% +it's not a natural monopoly it's not + + + align:start position:0% +it's not a natural monopoly it's not +like one the only one forum can be in + + align:start position:0% +like one the only one forum can be in + + + align:start position:0% +like one the only one forum can be in +there multiple firms are in there but + + align:start position:0% +there multiple firms are in there but + + + align:start position:0% +there multiple firms are in there but +they only know that to compete with each + + align:start position:0% +they only know that to compete with each + + + align:start position:0% +they only know that to compete with each +other not with the big wide world okay + + align:start position:0% +other not with the big wide world okay + + + align:start position:0% +other not with the big wide world okay +so for example the classic example an + + align:start position:0% +so for example the classic example an + + + align:start position:0% +so for example the classic example an +oligopoly is should be the auto industry + + align:start position:0% +oligopoly is should be the auto industry + + + align:start position:0% +oligopoly is should be the auto industry +it's a auto manufacturers clearly + + align:start position:0% +it's a auto manufacturers clearly + + + align:start position:0% +it's a auto manufacturers clearly +compete clearly if you watch any + + align:start position:0% +compete clearly if you watch any + + + align:start position:0% +compete clearly if you watch any +sporting event and watch how much + + align:start position:0% +sporting event and watch how much + + + align:start position:0% +sporting event and watch how much +advertising that goes on they clearly + + align:start position:0% +advertising that goes on they clearly + + + align:start position:0% +advertising that goes on they clearly +are competing with each other that can + + align:start position:0% +are competing with each other that can + + + align:start position:0% +are competing with each other that can +prank each other all the time + + align:start position:0% +prank each other all the time + + + align:start position:0% +prank each other all the time +but there's only all on most of the cars + + align:start position:0% +but there's only all on most of the cars + + + align:start position:0% +but there's only all on most of the cars +in the world are produced by fewer than + + align:start position:0% +in the world are produced by fewer than + + + align:start position:0% +in the world are produced by fewer than +ten auto manufacturers the notion that + + align:start position:0% +ten auto manufacturers the notion that + + + align:start position:0% +ten auto manufacturers the notion that +we have but a perfectly competitive + + align:start position:0% +we have but a perfectly competitive + + + align:start position:0% +we have but a perfectly competitive +market of thousands of sellers selling + + align:start position:0% +market of thousands of sellers selling + + + align:start position:0% +market of thousands of sellers selling +identical goods it's clearly not right + + align:start position:0% +identical goods it's clearly not right + + + align:start position:0% +identical goods it's clearly not right +when it comes to buying a car so that's + + align:start position:0% +when it comes to buying a car so that's + + + align:start position:0% +when it comes to buying a car so that's +sort of the model we're gonna want to + + align:start position:0% +sort of the model we're gonna want to + + + align:start position:0% +sort of the model we're gonna want to +focus on for the next few lectures + + align:start position:0% +focus on for the next few lectures + + + align:start position:0% +focus on for the next few lectures +now within Oh within an oligopoly market + + align:start position:0% + + + + align:start position:0% + +whenever we think about this market we + + align:start position:0% +whenever we think about this market we + + + align:start position:0% +whenever we think about this market we +want to start by noting that within this + + align:start position:0% +want to start by noting that within this + + + align:start position:0% +want to start by noting that within this +market the limited set of competitors + + align:start position:0% +market the limited set of competitors + + + align:start position:0% +market the limited set of competitors +can behave in two ways then we can + + align:start position:0% +can behave in two ways then we can + + + align:start position:0% +can behave in two ways then we can +behave cooperatively cooperatively or + + align:start position:0% +behave cooperatively cooperatively or + + + align:start position:0% +behave cooperatively cooperatively or +non cooperatively okay cooperative means + + align:start position:0% +non cooperatively okay cooperative means + + + align:start position:0% +non cooperatively okay cooperative means +they can form what's called a cartel so + + align:start position:0% +they can form what's called a cartel so + + + align:start position:0% +they can form what's called a cartel so +when there's an oligopoly market and the + + align:start position:0% +when there's an oligopoly market and the + + + align:start position:0% +when there's an oligopoly market and the +firm's cooperatively get together and + + align:start position:0% +firm's cooperatively get together and + + + align:start position:0% +firm's cooperatively get together and +make decisions that's called the cartel + + align:start position:0% +make decisions that's called the cartel + + + align:start position:0% +make decisions that's called the cartel +the most famous example of which is OPEC + + align:start position:0% +the most famous example of which is OPEC + + + align:start position:0% +the most famous example of which is OPEC +the Organization of Petroleum Exporting + + align:start position:0% +the Organization of Petroleum Exporting + + + align:start position:0% +the Organization of Petroleum Exporting +Countries which are the set of countries + + align:start position:0% +Countries which are the set of countries + + + align:start position:0% +Countries which are the set of countries +that control about two-thirds of the + + align:start position:0% +that control about two-thirds of the + + + align:start position:0% +that control about two-thirds of the +words world's oil led by Saudi Arabia is + + align:start position:0% +words world's oil led by Saudi Arabia is + + + align:start position:0% +words world's oil led by Saudi Arabia is +the major player in in OPEC it's a + + align:start position:0% +the major player in in OPEC it's a + + + align:start position:0% +the major player in in OPEC it's a +cartel about a dozen nations and what + + align:start position:0% +cartel about a dozen nations and what + + + align:start position:0% +cartel about a dozen nations and what +they do is they control the vast + + align:start position:0% +they do is they control the vast + + + align:start position:0% +they do is they control the vast +majority of the world's oil reserves and + + align:start position:0% +majority of the world's oil reserves and + + + align:start position:0% +majority of the world's oil reserves and +by behaving cooperatively they + + align:start position:0% +by behaving cooperatively they + + + align:start position:0% +by behaving cooperatively they +essentially turn themselves into a + + align:start position:0% +essentially turn themselves into a + + + align:start position:0% +essentially turn themselves into a +monopoly OPEC acts as if they've got + + align:start position:0% +monopoly OPEC acts as if they've got + + + align:start position:0% +monopoly OPEC acts as if they've got +sort of got the monopoly on oil + + align:start position:0% +sort of got the monopoly on oil + + + align:start position:0% +sort of got the monopoly on oil +certainly they they used to now it's + + align:start position:0% +certainly they they used to now it's + + + align:start position:0% +certainly they they used to now it's +getting harder other Kanaan OPEC + + align:start position:0% +getting harder other Kanaan OPEC + + + align:start position:0% +getting harder other Kanaan OPEC +countries are started producing more oil + + align:start position:0% +countries are started producing more oil + + + align:start position:0% +countries are started producing more oil +and breaking down but for a long time + + align:start position:0% +and breaking down but for a long time + + + align:start position:0% +and breaking down but for a long time +they were essentially the co-operative + + align:start position:0% +they were essentially the co-operative + + + align:start position:0% +they were essentially the co-operative +Peru savoia land act essentially like a + + align:start position:0% +Peru savoia land act essentially like a + + + align:start position:0% +Peru savoia land act essentially like a +monopoly and they made lots of profits + + align:start position:0% +monopoly and they made lots of profits + + + align:start position:0% +monopoly and they made lots of profits +like a monopoly they kept prices high + + align:start position:0% +like a monopoly they kept prices high + + + align:start position:0% +like a monopoly they kept prices high +they kept production inefficiently low + + align:start position:0% +they kept production inefficiently low + + + align:start position:0% +they kept production inefficiently low +and they made lots of money okay however + + align:start position:0% +and they made lots of money okay however + + + align:start position:0% +and they made lots of money okay however +um that's a great outcome for producers + + align:start position:0% +um that's a great outcome for producers + + + align:start position:0% +um that's a great outcome for producers +but as we'll talk about next time it's + + align:start position:0% +but as we'll talk about next time it's + + + align:start position:0% +but as we'll talk about next time it's +actually a hard outcome to enforce + + align:start position:0% +actually a hard outcome to enforce + + + align:start position:0% +actually a hard outcome to enforce +turned out to be hard to keep cartels + + align:start position:0% +turned out to be hard to keep cartels + + + align:start position:0% +turned out to be hard to keep cartels +together and so typically oligopoly + + align:start position:0% +together and so typically oligopoly + + + align:start position:0% +together and so typically oligopoly +markets behave in a non cooperative way + + align:start position:0% +markets behave in a non cooperative way + + + align:start position:0% +markets behave in a non cooperative way +with the participants competing with + + align:start position:0% +with the participants competing with + + + align:start position:0% +with the participants competing with +each other not cooperating with each + + align:start position:0% +each other not cooperating with each + + + align:start position:0% +each other not cooperating with each +other and in this case you can actually + + align:start position:0% +other and in this case you can actually + + + align:start position:0% +other and in this case you can actually +get them driving their profits down far + + align:start position:0% +get them driving their profits down far + + + align:start position:0% +get them driving their profits down far +below the monopoly level and indeed + + align:start position:0% +below the monopoly level and indeed + + + align:start position:0% +below the monopoly level and indeed +perhaps even all the way to the + + align:start position:0% +perhaps even all the way to the + + + align:start position:0% +perhaps even all the way to the +competitive level so you think about + + align:start position:0% +competitive level so you think about + + + align:start position:0% +competitive level so you think about +markets as a competitive is one extreme + + align:start position:0% +markets as a competitive is one extreme + + + align:start position:0% +markets as a competitive is one extreme +and the monopolies the other extreme + + align:start position:0% +and the monopolies the other extreme + + + align:start position:0% +and the monopolies the other extreme +oligopoly in between a cooperative + + align:start position:0% +oligopoly in between a cooperative + + + align:start position:0% +oligopoly in between a cooperative +oligopoly market like cartel will end up + + align:start position:0% +oligopoly market like cartel will end up + + + align:start position:0% +oligopoly market like cartel will end up +close to the monopoly outcome a non + + align:start position:0% +close to the monopoly outcome a non + + + align:start position:0% +close to the monopoly outcome a non +cooperative market well it's somewhere + + align:start position:0% +cooperative market well it's somewhere + + + align:start position:0% +cooperative market well it's somewhere +in between and we're gonna model today + + align:start position:0% +in between and we're gonna model today + + + align:start position:0% +in between and we're gonna model today +is we're in between do they end up okay + + align:start position:0% +is we're in between do they end up okay + + + align:start position:0% +is we're in between do they end up okay +now to think about this we're gonna have + + align:start position:0% +now to think about this we're gonna have + + + align:start position:0% +now to think about this we're gonna have +to turn to a tool which has really + + align:start position:0% +to turn to a tool which has really + + + align:start position:0% +to turn to a tool which has really +become a dominant tool in economics over + + align:start position:0% +become a dominant tool in economics over + + + align:start position:0% +become a dominant tool in economics over +the last 40 years which is the tool of + + align:start position:0% +the last 40 years which is the tool of + + + align:start position:0% +the last 40 years which is the tool of +game theory + + align:start position:0% + + + + align:start position:0% + +game theory so basically we could think + + align:start position:0% +game theory so basically we could think + + + align:start position:0% +game theory so basically we could think +of all look up we're gonna think of + + align:start position:0% +of all look up we're gonna think of + + + align:start position:0% +of all look up we're gonna think of +oligopoly firms as engaging in a game + + align:start position:0% +oligopoly firms as engaging in a game + + + align:start position:0% +oligopoly firms as engaging in a game +okay and as with any game you need to + + align:start position:0% +okay and as with any game you need to + + + align:start position:0% +okay and as with any game you need to +sort of know two things one is you need + + align:start position:0% +sort of know two things one is you need + + + align:start position:0% +sort of know two things one is you need +to know what's the strategy and the + + align:start position:0% +to know what's the strategy and the + + + align:start position:0% +to know what's the strategy and the +second is you need to know when is the + + align:start position:0% +second is you need to know when is the + + + align:start position:0% +second is you need to know when is the +game over kind of what's the equilibrium + + align:start position:0% + + + + align:start position:0% + +and that's sort of essentially what you + + align:start position:0% +and that's sort of essentially what you + + + align:start position:0% +and that's sort of essentially what you +tell with any game and so basically what + + align:start position:0% +tell with any game and so basically what + + + align:start position:0% +tell with any game and so basically what +we're gonna do the key with game theory + + align:start position:0% +we're gonna do the key with game theory + + + align:start position:0% +we're gonna do the key with game theory +is that we are going to define the + + align:start position:0% +is that we are going to define the + + + align:start position:0% +is that we are going to define the +equilibrium and that's going to yield + + align:start position:0% +equilibrium and that's going to yield + + + align:start position:0% +equilibrium and that's going to yield +for us the strategy that players are + + align:start position:0% +for us the strategy that players are + + + align:start position:0% +for us the strategy that players are +going to use however equilibrium in a + + align:start position:0% +going to use however equilibrium in a + + + align:start position:0% +going to use however equilibrium in a +game is not well-defined it's like a set + + align:start position:0% +game is not well-defined it's like a set + + + align:start position:0% +game is not well-defined it's like a set +of rules that are printed out like + + align:start position:0% +of rules that are printed out like + + + align:start position:0% +of rules that are printed out like +monopoly in a non cooperative oligopoly + + align:start position:0% +monopoly in a non cooperative oligopoly + + + align:start position:0% +monopoly in a non cooperative oligopoly +market the equilibrium you have to + + align:start position:0% +market the equilibrium you have to + + + align:start position:0% +market the equilibrium you have to +actually come up with different concepts + + align:start position:0% +actually come up with different concepts + + + align:start position:0% +actually come up with different concepts +of what equilibrium is there's not a + + align:start position:0% +of what equilibrium is there's not a + + + align:start position:0% +of what equilibrium is there's not a +hard-and-fast scientific rule and the + + align:start position:0% +hard-and-fast scientific rule and the + + + align:start position:0% +hard-and-fast scientific rule and the +typical one that's used is called the + + align:start position:0% +typical one that's used is called the + + + align:start position:0% +typical one that's used is called the +Nash equilibrium the Nash equilibrium + + align:start position:0% +Nash equilibrium the Nash equilibrium + + + align:start position:0% +Nash equilibrium the Nash equilibrium +named for the John Nash the famous + + align:start position:0% +named for the John Nash the famous + + + align:start position:0% +named for the John Nash the famous +mathematician who economists have + + align:start position:0% +mathematician who economists have + + + align:start position:0% +mathematician who economists have +claimed as their own even though it's + + align:start position:0% +claimed as their own even though it's + + + align:start position:0% +claimed as their own even though it's +really a mathematician but we get in the + + align:start position:0% +really a mathematician but we get in the + + + align:start position:0% +really a mathematician but we get in the +Nobel Prize anyway and you know if you + + align:start position:0% +Nobel Prize anyway and you know if you + + + align:start position:0% +Nobel Prize anyway and you know if you +think of this in comments probably one + + align:start position:0% +think of this in comments probably one + + + align:start position:0% +think of this in comments probably one +of most famous you know you all know + + align:start position:0% +of most famous you know you all know + + + align:start position:0% +of most famous you know you all know +about the movie and book Beautiful Mind + + align:start position:0% +about the movie and book Beautiful Mind + + + align:start position:0% +about the movie and book Beautiful Mind +he is basically the father of of game + + align:start position:0% +he is basically the father of of game + + + align:start position:0% +he is basically the father of of game +theory okay so basically what is the + + align:start position:0% +theory okay so basically what is the + + + align:start position:0% +theory okay so basically what is the +Nash equilibrium the Nash equilibria is + + align:start position:0% +Nash equilibrium the Nash equilibria is + + + align:start position:0% +Nash equilibrium the Nash equilibria is +defined as the point at which no player + + align:start position:0% +defined as the point at which no player + + + align:start position:0% +defined as the point at which no player +wants to change their strategy given + + align:start position:0% +wants to change their strategy given + + + align:start position:0% +wants to change their strategy given +what the other players are doing so the + + align:start position:0% +what the other players are doing so the + + + align:start position:0% +what the other players are doing so the +point at which no player wants to change + + align:start position:0% +point at which no player wants to change + + + align:start position:0% +point at which no player wants to change +its strategy given what the other + + align:start position:0% +its strategy given what the other + + + align:start position:0% +its strategy given what the other +players are doing so in lodz every + + align:start position:0% +players are doing so in lodz every + + + align:start position:0% +players are doing so in lodz every +player is happy with where they are + + align:start position:0% +player is happy with where they are + + + align:start position:0% +player is happy with where they are +given what every other players decided + + align:start position:0% +given what every other players decided + + + align:start position:0% +given what every other players decided +I'm happy to do what I've decided so + + align:start position:0% +I'm happy to do what I've decided so + + + align:start position:0% +I'm happy to do what I've decided so +I've got a strategy and given the + + align:start position:0% +I've got a strategy and given the + + + align:start position:0% +I've got a strategy and given the +strategy other players are using if I'm + + align:start position:0% +strategy other players are using if I'm + + + align:start position:0% +strategy other players are using if I'm +happy with my strategy then that's an + + align:start position:0% +happy with my strategy then that's an + + + align:start position:0% +happy with my strategy then that's an +equilibrium okay so this is a super + + align:start position:0% +equilibrium okay so this is a super + + + align:start position:0% +equilibrium okay so this is a super +abstract concept so let's illustrate it + + align:start position:0% +abstract concept so let's illustrate it + + + align:start position:0% +abstract concept so let's illustrate it +with an example and the classic example + + align:start position:0% +with an example and the classic example + + + align:start position:0% +with an example and the classic example +of game theory is the prisoner's dilemma + + align:start position:0% + + + + align:start position:0% + +which many of you I'm sure know about + + align:start position:0% +which many of you I'm sure know about + + + align:start position:0% +which many of you I'm sure know about +maybe than most of you but let's just go + + align:start position:0% +maybe than most of you but let's just go + + + align:start position:0% +maybe than most of you but let's just go +through it this is the thing from the + + align:start position:0% +through it this is the thing from the + + + align:start position:0% +through it this is the thing from the +old cop movies you see where they arrest + + align:start position:0% +old cop movies you see where they arrest + + + align:start position:0% +old cop movies you see where they arrest +two guys and they put them in separate + + align:start position:0% +two guys and they put them in separate + + + align:start position:0% +two guys and they put them in separate +rooms and they basically interrogate + + align:start position:0% +rooms and they basically interrogate + + + align:start position:0% +rooms and they basically interrogate +them separately ok and what they say is + + align:start position:0% +them separately ok and what they say is + + + align:start position:0% +them separately ok and what they say is +um they're put in separate rooms and + + align:start position:0% +um they're put in separate rooms and + + + align:start position:0% +um they're put in separate rooms and +let's say that these guys get told to + + align:start position:0% +let's say that these guys get told to + + + align:start position:0% +let's say that these guys get told to +follow and they each get told separately + + align:start position:0% +follow and they each get told separately + + + align:start position:0% +follow and they each get told separately +the following thing they get told that + + align:start position:0% +the following thing they get told that + + + align:start position:0% +the following thing they get told that +right now if nothing else happens + + align:start position:0% +right now if nothing else happens + + + align:start position:0% +right now if nothing else happens +there's enough evidence to send them + + align:start position:0% +there's enough evidence to send them + + + align:start position:0% +there's enough evidence to send them +each away for one year however they're + + align:start position:0% +each away for one year however they're + + + align:start position:0% +each away for one year however they're +told if they turn on their friend and + + align:start position:0% +told if they turn on their friend and + + + align:start position:0% +told if they turn on their friend and +say and say their friends guilty then + + align:start position:0% +say and say their friends guilty then + + + align:start position:0% +say and say their friends guilty then +they go free and their friend gets five + + align:start position:0% +they go free and their friend gets five + + + align:start position:0% +they go free and their friend gets five +years if their friend turns on them then + + align:start position:0% +years if their friend turns on them then + + + align:start position:0% +years if their friend turns on them then +the friend goes free and they get five + + align:start position:0% +the friend goes free and they get five + + + align:start position:0% +the friend goes free and they get five +years but if they both turn on each + + align:start position:0% +years but if they both turn on each + + + align:start position:0% +years but if they both turn on each +other + + align:start position:0% +other + + + align:start position:0% +other +they both get two years okay set up as + + align:start position:0% +they both get two years okay set up as + + + align:start position:0% +they both get two years okay set up as +if they both stay silent they both get + + align:start position:0% +if they both stay silent they both get + + + align:start position:0% +if they both stay silent they both get +one year if one turns then that person + + align:start position:0% +one year if one turns then that person + + + align:start position:0% +one year if one turns then that person +gets to leave in the other person gets + + align:start position:0% +gets to leave in the other person gets + + + align:start position:0% +gets to leave in the other person gets +five years but if they both turn then + + align:start position:0% +five years but if they both turn then + + + align:start position:0% +five years but if they both turn then +these get two years so how do we think + + align:start position:0% +these get two years so how do we think + + + align:start position:0% +these get two years so how do we think +about decision making that context the + + align:start position:0% +about decision making that context the + + + align:start position:0% +about decision making that context the +way we do that is we write down we call + + align:start position:0% +way we do that is we write down we call + + + align:start position:0% +way we do that is we write down we call +a payoff matrix we sort of write down a + + align:start position:0% +a payoff matrix we sort of write down a + + + align:start position:0% +a payoff matrix we sort of write down a +matrix form this decision so let's think + + align:start position:0% +matrix form this decision so let's think + + + align:start position:0% +matrix form this decision so let's think +about it what a playoff matrix look like + + align:start position:0% +about it what a playoff matrix look like + + + align:start position:0% +about it what a playoff matrix look like +up here a prisoner B and here you have + + align:start position:0% +up here a prisoner B and here you have + + + align:start position:0% +up here a prisoner B and here you have +prisoner a for centre a and prisoner a + + align:start position:0% +prisoner a for centre a and prisoner a + + + align:start position:0% +prisoner a for centre a and prisoner a +can remain silent or they can talk and + + align:start position:0% +can remain silent or they can talk and + + + align:start position:0% +can remain silent or they can talk and +prisoner B can remain silent + + align:start position:0% +prisoner B can remain silent + + + align:start position:0% +prisoner B can remain silent +or they can talk okay + + align:start position:0% +or they can talk okay + + + align:start position:0% +or they can talk okay +and then we just write down what are the + + align:start position:0% +and then we just write down what are the + + + align:start position:0% +and then we just write down what are the +outcomes or the payoffs from these + + align:start position:0% +outcomes or the payoffs from these + + + align:start position:0% +outcomes or the payoffs from these +different strategies so prisoner a says + + align:start position:0% +different strategies so prisoner a says + + + align:start position:0% +different strategies so prisoner a says +nothing and prisoner B says nothing then + + align:start position:0% +nothing and prisoner B says nothing then + + + align:start position:0% +nothing and prisoner B says nothing then +a gets one year and B gets one year if + + align:start position:0% +a gets one year and B gets one year if + + + align:start position:0% +a gets one year and B gets one year if +prisoner a says nothing and prisoner B + + align:start position:0% +prisoner a says nothing and prisoner B + + + align:start position:0% +prisoner a says nothing and prisoner B +says oh yeah prisoner a he's definitely + + align:start position:0% +says oh yeah prisoner a he's definitely + + + align:start position:0% +says oh yeah prisoner a he's definitely +guilty then prisoner a gets five years + + align:start position:0% +guilty then prisoner a gets five years + + + align:start position:0% +guilty then prisoner a gets five years +and prisoner being at zero years if the + + align:start position:0% +and prisoner being at zero years if the + + + align:start position:0% +and prisoner being at zero years if the +opposite happens if prisoner he says + + align:start position:0% +opposite happens if prisoner he says + + + align:start position:0% +opposite happens if prisoner he says +yeah B's guilty and B doesn't say + + align:start position:0% +yeah B's guilty and B doesn't say + + + align:start position:0% +yeah B's guilty and B doesn't say +anything about a then a gets zero years + + align:start position:0% +anything about a then a gets zero years + + + align:start position:0% +anything about a then a gets zero years +and B gets five years but if they both + + align:start position:0% +and B gets five years but if they both + + + align:start position:0% +and B gets five years but if they both +say the other ones guilty then they each + + align:start position:0% +say the other ones guilty then they each + + + align:start position:0% +say the other ones guilty then they each +get two years okay that's the payoff + + align:start position:0% +get two years okay that's the payoff + + + align:start position:0% +get two years okay that's the payoff +matrix okay and now we want to ask given + + align:start position:0% +matrix okay and now we want to ask given + + + align:start position:0% +matrix okay and now we want to ask given +this payoff matrix what is the right + + align:start position:0% +this payoff matrix what is the right + + + align:start position:0% +this payoff matrix what is the right +strategy for each prisoner to pursue and + + align:start position:0% +strategy for each prisoner to pursue and + + + align:start position:0% +strategy for each prisoner to pursue and +the way we do this in the Nash + + align:start position:0% +the way we do this in the Nash + + + align:start position:0% +the way we do this in the Nash +equilibria makaan cept is we look for a + + align:start position:0% +equilibria makaan cept is we look for a + + + align:start position:0% +equilibria makaan cept is we look for a +dominant strategy it's very strategy + + align:start position:0% +dominant strategy it's very strategy + + + align:start position:0% +dominant strategy it's very strategy +that I would pursue regardless of what + + align:start position:0% +that I would pursue regardless of what + + + align:start position:0% +that I would pursue regardless of what +the other person does and if there is + + align:start position:0% +the other person does and if there is + + + align:start position:0% +the other person does and if there is +I'll pursue that because remember the + + align:start position:0% +I'll pursue that because remember the + + + align:start position:0% +I'll pursue that because remember the +national Calibri concept is what do I + + align:start position:0% +national Calibri concept is what do I + + + align:start position:0% +national Calibri concept is what do I +want to do given what the other person's + + align:start position:0% +want to do given what the other person's + + + align:start position:0% +want to do given what the other person's +doing if I have a strategy I want to do + + align:start position:0% +doing if I have a strategy I want to do + + + align:start position:0% +doing if I have a strategy I want to do +no matter what the other person is doing + + align:start position:0% +no matter what the other person is doing + + + align:start position:0% +no matter what the other person is doing +then I'll do it so and ask is there a + + align:start position:0% +then I'll do it so and ask is there a + + + align:start position:0% +then I'll do it so and ask is there a +dominant strategy is there a strategy + + align:start position:0% +dominant strategy is there a strategy + + + align:start position:0% +dominant strategy is there a strategy +there's the best thing to do no matter + + align:start position:0% +there's the best thing to do no matter + + + align:start position:0% +there's the best thing to do no matter +what the other guy does okay well + + align:start position:0% +what the other guy does okay well + + + align:start position:0% +what the other guy does okay well +clearly if they're cooperating if these + + align:start position:0% +clearly if they're cooperating if these + + + align:start position:0% +clearly if they're cooperating if these +were these were stupid police and they + + align:start position:0% +were these were stupid police and they + + + align:start position:0% +were these were stupid police and they +sat in the same room told us then left + + align:start position:0% +sat in the same room told us then left + + + align:start position:0% +sat in the same room told us then left +the two guys cooperating said well + + align:start position:0% +the two guys cooperating said well + + + align:start position:0% +the two guys cooperating said well +clearly the dominant cooperative + + align:start position:0% +clearly the dominant cooperative + + + align:start position:0% +clearly the dominant cooperative +strategy is for all of us to remain + + align:start position:0% +strategy is for all of us to remain + + + align:start position:0% +strategy is for all of us to remain +silent that's the dominant coopera + + align:start position:0% +silent that's the dominant coopera + + + align:start position:0% +silent that's the dominant coopera +strategy then as a team we only get two + + align:start position:0% +strategy then as a team we only get two + + + align:start position:0% +strategy then as a team we only get two +total years in jail where everything + + align:start position:0% +total years in jail where everything + + + align:start position:0% +total years in jail where everything +gives much more many more years in jail + + align:start position:0% +gives much more many more years in jail + + + align:start position:0% +gives much more many more years in jail +so they're buddies and they trust each + + align:start position:0% +so they're buddies and they trust each + + + align:start position:0% +so they're buddies and they trust each +other and they cooperate then that's the + + align:start position:0% +other and they cooperate then that's the + + + align:start position:0% +other and they cooperate then that's the +closest right strategy well let's say + + align:start position:0% +closest right strategy well let's say + + + align:start position:0% +closest right strategy well let's say +the police are smart and put them in + + align:start position:0% +the police are smart and put them in + + + align:start position:0% +the police are smart and put them in +separate rooms + + align:start position:0% +separate rooms + + + align:start position:0% +separate rooms +okay well what's the dominant + + align:start position:0% +okay well what's the dominant + + + align:start position:0% +okay well what's the dominant +non-cooperative strategy what is the + + align:start position:0% +non-cooperative strategy what is the + + + align:start position:0% +non-cooperative strategy what is the +strategy that a or b that aides say a + + align:start position:0% +strategy that a or b that aides say a + + + align:start position:0% +strategy that a or b that aides say a +should produce yeah why + + align:start position:0% +should produce yeah why + + + align:start position:0% +should produce yeah why +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +in silence you talk you get zero and if + + align:start position:0% +in silence you talk you get zero and if + + + align:start position:0% +in silence you talk you get zero and if +they're talking they talking you talk as + + align:start position:0% +they're talking they talking you talk as + + + align:start position:0% +they're talking they talking you talk as +well you get 2 vs. 5 exactly 4 person or + + align:start position:0% +well you get 2 vs. 5 exactly 4 person or + + + align:start position:0% +well you get 2 vs. 5 exactly 4 person or +a in this first row compared the first + + align:start position:0% +a in this first row compared the first + + + align:start position:0% +a in this first row compared the first +row left first column will say prisoner + + align:start position:0% +row left first column will say prisoner + + + align:start position:0% +row left first column will say prisoner +be silent then clearly you're better off + + align:start position:0% +be silent then clearly you're better off + + + align:start position:0% +be silent then clearly you're better off +talking than not talking 0 rather than 1 + + align:start position:0% +talking than not talking 0 rather than 1 + + + align:start position:0% +talking than not talking 0 rather than 1 +let's say prisoner B talks then you're + + align:start position:0% +let's say prisoner B talks then you're + + + align:start position:0% +let's say prisoner B talks then you're +still better off talking than not + + align:start position:0% +still better off talking than not + + + align:start position:0% +still better off talking than not +talking so no matter what B does you + + align:start position:0% +talking so no matter what B does you + + + align:start position:0% +talking so no matter what B does you +should talk + + align:start position:0% +should talk + + + align:start position:0% +should talk +likewise prisoner B no matter what a + + align:start position:0% +likewise prisoner B no matter what a + + + align:start position:0% +likewise prisoner B no matter what a +does B should talk so the + + align:start position:0% +does B should talk so the + + + align:start position:0% +does B should talk so the +non-cooperative room is actually this + + align:start position:0% +non-cooperative room is actually this + + + align:start position:0% +non-cooperative room is actually this +outcome they both end up talking you get + + align:start position:0% +outcome they both end up talking you get + + + align:start position:0% +outcome they both end up talking you get +sort of a race to the bottom + + align:start position:0% +sort of a race to the bottom + + + align:start position:0% +sort of a race to the bottom +the non-cooperative outcome is much + + align:start position:0% +the non-cooperative outcome is much + + + align:start position:0% +the non-cooperative outcome is much +worse than if they could have cooperated + + align:start position:0% +worse than if they could have cooperated + + + align:start position:0% +worse than if they could have cooperated +ok so basically what you get is that the + + align:start position:0% +ok so basically what you get is that the + + + align:start position:0% +ok so basically what you get is that the +non-cooperative equilibrium is always + + align:start position:0% +non-cooperative equilibrium is always + + + align:start position:0% +non-cooperative equilibrium is always +worse for the players than the + + align:start position:0% +worse for the players than the + + + align:start position:0% +worse for the players than the +co-operative equilibria and this was + + align:start position:0% +co-operative equilibria and this was + + + align:start position:0% +co-operative equilibria and this was +like an unbelievable insight of Nash + + align:start position:0% +like an unbelievable insight of Nash + + + align:start position:0% +like an unbelievable insight of Nash +before Nash we always thought + + align:start position:0% +before Nash we always thought + + + align:start position:0% +before Nash we always thought +competition was always than ever we're + + align:start position:0% +competition was always than ever we're + + + align:start position:0% +competition was always than ever we're +good with some more competitions better + + align:start position:0% +good with some more competitions better + + + align:start position:0% +good with some more competitions better +for the reasons we taught you in the + + align:start position:0% +for the reasons we taught you in the + + + align:start position:0% +for the reasons we taught you in the +first 10 or 10 or 12 lectures of this + + align:start position:0% +first 10 or 10 or 12 lectures of this + + + align:start position:0% +first 10 or 10 or 12 lectures of this +class Nash was the first one to say no + + align:start position:0% +class Nash was the first one to say no + + + align:start position:0% +class Nash was the first one to say no +actually competition can be bad + + align:start position:0% +actually competition can be bad + + + align:start position:0% +actually competition can be bad +cooperation can be better as you + + align:start position:0% +cooperation can be better as you + + + align:start position:0% +cooperation can be better as you +remember the scene in a beautiful mind + + align:start position:0% +remember the scene in a beautiful mind + + + align:start position:0% +remember the scene in a beautiful mind +where they're picking up girls in the + + align:start position:0% +where they're picking up girls in the + + + align:start position:0% +where they're picking up girls in the +bar and he describes sort of basically a + + align:start position:0% +bar and he describes sort of basically a + + + align:start position:0% +bar and he describes sort of basically a +Nash strategy ok how competition lead to + + align:start position:0% +Nash strategy ok how competition lead to + + + align:start position:0% +Nash strategy ok how competition lead to +the worst outcome ok and basically + + align:start position:0% +the worst outcome ok and basically + + + align:start position:0% +the worst outcome ok and basically +that's what you see here that + + align:start position:0% +that's what you see here that + + + align:start position:0% +that's what you see here that +competition can actually lead to a worse + + align:start position:0% +competition can actually lead to a worse + + + align:start position:0% +competition can actually lead to a worse +outcome than cooperation and that was + + align:start position:0% +outcome than cooperation and that was + + + align:start position:0% +outcome than cooperation and that was +really sort of Nash's sort of brilliant + + align:start position:0% +really sort of Nash's sort of brilliant + + + align:start position:0% +really sort of Nash's sort of brilliant +insight now um this is a sort of a cute + + align:start position:0% +insight now um this is a sort of a cute + + + align:start position:0% +insight now um this is a sort of a cute +example of prisoners but actually but + + align:start position:0% +example of prisoners but actually but + + + align:start position:0% +example of prisoners but actually but +well for two points first of all this + + align:start position:0% +well for two points first of all this + + + align:start position:0% +well for two points first of all this +generally shows you how you do gain fear + + align:start position:0% +generally shows you how you do gain fear + + + align:start position:0% +generally shows you how you do gain fear +with Nash with Nash equilibria basically + + align:start position:0% +with Nash with Nash equilibria basically + + + align:start position:0% +with Nash with Nash equilibria basically +you look at the payoff matrix you find + + align:start position:0% +you look at the payoff matrix you find + + + align:start position:0% +you look at the payoff matrix you find +the dominant strategy and then you find + + align:start position:0% +the dominant strategy and then you find + + + align:start position:0% +the dominant strategy and then you find +where those dominant strategies + + align:start position:0% +where those dominant strategies + + + align:start position:0% +where those dominant strategies +intersect and here the dominant + + align:start position:0% +intersect and here the dominant + + + align:start position:0% +intersect and here the dominant +strategies intersect at this cell + + align:start position:0% +strategies intersect at this cell + + + align:start position:0% +strategies intersect at this cell +therefore that's the equilibrium okay so + + align:start position:0% +therefore that's the equilibrium okay so + + + align:start position:0% +therefore that's the equilibrium okay so +that's basically how you do game theory + + align:start position:0% +that's basically how you do game theory + + + align:start position:0% +that's basically how you do game theory +you know you know + + align:start position:0% +you know you know + + + align:start position:0% +you know you know +getting through kindergarten level okay + + align:start position:0% +getting through kindergarten level okay + + + align:start position:0% +getting through kindergarten level okay +you look at the matrix you find each + + align:start position:0% +you look at the matrix you find each + + + align:start position:0% +you look at the matrix you find each +player's dominus strategy and you find + + align:start position:0% +player's dominus strategy and you find + + + align:start position:0% +player's dominus strategy and you find +the point at which those dominant + + align:start position:0% +the point at which those dominant + + + align:start position:0% +the point at which those dominant +strategies intersect and at that point + + align:start position:0% +strategies intersect and at that point + + + align:start position:0% +strategies intersect and at that point +that's the equilibrium now that's all + + align:start position:0% +that's the equilibrium now that's all + + + align:start position:0% +that's the equilibrium now that's all +well and good for sort of a simple + + align:start position:0% +well and good for sort of a simple + + + align:start position:0% +well and good for sort of a simple +example like this but let's actually + + align:start position:0% +example like this but let's actually + + + align:start position:0% +example like this but let's actually +apply to an economics example let's + + align:start position:0% +apply to an economics example let's + + + align:start position:0% +apply to an economics example let's +think about advertising + + align:start position:0% +think about advertising + + + align:start position:0% +think about advertising +so think about Coke and Pepsi okay um + + align:start position:0% +so think about Coke and Pepsi okay um + + + align:start position:0% +so think about Coke and Pepsi okay um +now right now let's think about their + + align:start position:0% +now right now let's think about their + + + align:start position:0% +now right now let's think about their +decision advertise now obviously this is + + align:start position:0% +decision advertise now obviously this is + + + align:start position:0% +decision advertise now obviously this is +a simple problem obviously Pepsi should + + align:start position:0% +a simple problem obviously Pepsi should + + + align:start position:0% +a simple problem obviously Pepsi should +just be illegal because cokes just way + + align:start position:0% +just be illegal because cokes just way + + + align:start position:0% +just be illegal because cokes just way +better but sadly it's not and sometimes + + align:start position:0% +better but sadly it's not and sometimes + + + align:start position:0% +better but sadly it's not and sometimes +I have to drink Pepsi and I'm very sad + + align:start position:0% +I have to drink Pepsi and I'm very sad + + + align:start position:0% +I have to drink Pepsi and I'm very sad +but nonetheless in the real world we + + align:start position:0% +but nonetheless in the real world we + + + align:start position:0% +but nonetheless in the real world we +have Coke impacts they have to decide + + align:start position:0% +have Coke impacts they have to decide + + + align:start position:0% +have Coke impacts they have to decide +how much to advertise now the dominant + + align:start position:0% +how much to advertise now the dominant + + + align:start position:0% +how much to advertise now the dominant +cooperative strategy would be to say + + align:start position:0% +cooperative strategy would be to say + + + align:start position:0% +cooperative strategy would be to say +look advertising cost us a ton of money + + align:start position:0% +look advertising cost us a ton of money + + + align:start position:0% +look advertising cost us a ton of money +let's just split the market + + align:start position:0% +let's just split the market + + + align:start position:0% +let's just split the market +let's have monopoly market and just + + align:start position:0% +let's have monopoly market and just + + + align:start position:0% +let's have monopoly market and just +split it we're close to splitting it + + align:start position:0% +split it we're close to splitting it + + + align:start position:0% +split it we're close to splitting it +anyway cokes got some more of it we're + + align:start position:0% +anyway cokes got some more of it we're + + + align:start position:0% +anyway cokes got some more of it we're +close to splitting let's just split it + + align:start position:0% +close to splitting let's just split it + + + align:start position:0% +close to splitting let's just split it +yeah why different than the + + align:start position:0% +yeah why different than the + + + align:start position:0% +yeah why different than the +cooperative's that's that's imposed not + + align:start position:0% +cooperative's that's that's imposed not + + + align:start position:0% +cooperative's that's that's imposed not +by Coke and Pepsi jointly that's opposed + + align:start position:0% +by Coke and Pepsi jointly that's opposed + + + align:start position:0% +by Coke and Pepsi jointly that's opposed +by Pepsi saying to a university campus + + align:start position:0% +by Pepsi saying to a university campus + + + align:start position:0% +by Pepsi saying to a university campus +for example we will only we will cut you + + align:start position:0% +for example we will only we will cut you + + + align:start position:0% +for example we will only we will cut you +a better deal if you'll agree not to + + align:start position:0% +a better deal if you'll agree not to + + + align:start position:0% +a better deal if you'll agree not to +sell coke that's not cooperation that's + + align:start position:0% +sell coke that's not cooperation that's + + + align:start position:0% +sell coke that's not cooperation that's +competition okay so the quad there's a + + align:start position:0% +competition okay so the quad there's a + + + align:start position:0% +competition okay so the quad there's a +proper strategy what if they don't + + align:start position:0% +proper strategy what if they don't + + + align:start position:0% +proper strategy what if they don't +cooperate okay + + align:start position:0% +cooperate okay + + + align:start position:0% +cooperate okay +well let's imagine we are the following + + align:start position:0% +well let's imagine we are the following + + + align:start position:0% +well let's imagine we are the following +payoff matrix okay you've got Pepsi up + + align:start position:0% +payoff matrix okay you've got Pepsi up + + + align:start position:0% +payoff matrix okay you've got Pepsi up +here and they can advertise or not + + align:start position:0% +here and they can advertise or not + + + align:start position:0% +here and they can advertise or not +advertise and you've got Coke here and + + align:start position:0% +advertise and you've got Coke here and + + + align:start position:0% +advertise and you've got Coke here and +they can advertise or not advertise and + + align:start position:0% +they can advertise or not advertise and + + + align:start position:0% +they can advertise or not advertise and +let's say the payoff matrix is the + + align:start position:0% +let's say the payoff matrix is the + + + align:start position:0% +let's say the payoff matrix is the +following let's say if both Pepsi and + + align:start position:0% +following let's say if both Pepsi and + + + align:start position:0% +following let's say if both Pepsi and +Coke let's say that the total um let's + + align:start position:0% +Coke let's say that the total um let's + + + align:start position:0% +Coke let's say that the total um let's +say the total amount of profit to be + + align:start position:0% +say the total amount of profit to be + + + align:start position:0% +say the total amount of profit to be +made is 16 whatever a billion whatever + + align:start position:0% +made is 16 whatever a billion whatever + + + align:start position:0% +made is 16 whatever a billion whatever +units want to make it 16 billion okay + + align:start position:0% +units want to make it 16 billion okay + + + align:start position:0% +units want to make it 16 billion okay +and let's say if there's no advertising + + align:start position:0% +and let's say if there's no advertising + + + align:start position:0% +and let's say if there's no advertising +Coke gets 8m Pepsi gets eight okay + + align:start position:0% +Coke gets 8m Pepsi gets eight okay + + + align:start position:0% +Coke gets 8m Pepsi gets eight okay +but let's say but let's say advertising + + align:start position:0% +but let's say but let's say advertising + + + align:start position:0% +but let's say but let's say advertising +cost money it costs five five billion so + + align:start position:0% +cost money it costs five five billion so + + + align:start position:0% +cost money it costs five five billion so +let's say if they both advertise then + + align:start position:0% +let's say if they both advertise then + + + align:start position:0% +let's say if they both advertise then +they still end up splitting the market + + align:start position:0% +they still end up splitting the market + + + align:start position:0% +they still end up splitting the market +but they only make three C equals three + + align:start position:0% +but they only make three C equals three + + + align:start position:0% +but they only make three C equals three +P equals three so it's a I'm sorry it's + + align:start position:0% +P equals three so it's a I'm sorry it's + + + align:start position:0% +P equals three so it's a I'm sorry it's +the obviou advertising yes you're right + + align:start position:0% +the obviou advertising yes you're right + + + align:start position:0% +the obviou advertising yes you're right +C equals three P equals three and here C + + align:start position:0% +C equals three P equals three and here C + + + align:start position:0% +C equals three P equals three and here C +equals eight P equals eight okay so + + align:start position:0% +equals eight P equals eight okay so + + + align:start position:0% +equals eight P equals eight okay so +basically they are so basically of a + + align:start position:0% +basically they are so basically of a + + + align:start position:0% +basically they are so basically of a +situation where they both end up + + align:start position:0% +situation where they both end up + + + align:start position:0% +situation where they both end up +splitting the market either way but they + + align:start position:0% +splitting the market either way but they + + + align:start position:0% +splitting the market either way but they +just split a smaller net profit if they + + align:start position:0% +just split a smaller net profit if they + + + align:start position:0% +just split a smaller net profit if they +advertise so clearly they'd rather be + + align:start position:0% +advertise so clearly they'd rather be + + + align:start position:0% +advertise so clearly they'd rather be +here than here but what happens in the + + align:start position:0% +here than here but what happens in the + + + align:start position:0% +here than here but what happens in the +off-diagonal elements well let's say + + align:start position:0% +off-diagonal elements well let's say + + + align:start position:0% +off-diagonal elements well let's say +also that if coke advertises but Pepsi + + align:start position:0% +also that if coke advertises but Pepsi + + + align:start position:0% +also that if coke advertises but Pepsi +does not then let's say Coke ends up + + align:start position:0% +does not then let's say Coke ends up + + + align:start position:0% +does not then let's say Coke ends up +making 13 billion and Pepsi ends up + + align:start position:0% +making 13 billion and Pepsi ends up + + + align:start position:0% +making 13 billion and Pepsi ends up +making - I'm sorry if Coke advertises + + align:start position:0% +making - I'm sorry if Coke advertises + + + align:start position:0% +making - I'm sorry if Coke advertises +and if Coke advertises and Pepsi does + + align:start position:0% +and if Coke advertises and Pepsi does + + + align:start position:0% +and if Coke advertises and Pepsi does +not adjust what my teen and Pepsi makes + + align:start position:0% +not adjust what my teen and Pepsi makes + + + align:start position:0% +not adjust what my teen and Pepsi makes +negative - they actually lose money + + align:start position:0% +negative - they actually lose money + + + align:start position:0% +negative - they actually lose money +because a fixed cost then don't sell + + align:start position:0% +because a fixed cost then don't sell + + + align:start position:0% +because a fixed cost then don't sell +anything nobody buys perhaps their to + + align:start position:0% +anything nobody buys perhaps their to + + + align:start position:0% +anything nobody buys perhaps their to +lose money and let's say if Pepsi + + align:start position:0% +lose money and let's say if Pepsi + + + align:start position:0% +lose money and let's say if Pepsi +advertises and coke doesn't then coke + + align:start position:0% +advertises and coke doesn't then coke + + + align:start position:0% +advertises and coke doesn't then coke +makes negative - and Pepsi makes 13 okay + + align:start position:0% +makes negative - and Pepsi makes 13 okay + + + align:start position:0% +makes negative - and Pepsi makes 13 okay +so actually if you don't advertise + + align:start position:0% +so actually if you don't advertise + + + align:start position:0% +so actually if you don't advertise +you're really screwed and the other guys + + align:start position:0% +you're really screwed and the other guys + + + align:start position:0% +you're really screwed and the other guys +really screwed yeah this doesn't move + + align:start position:0% +really screwed yeah this doesn't move + + + align:start position:0% +really screwed yeah this doesn't move +the cost of advertising but it's just + + align:start position:0% +the cost of advertising but it's just + + + align:start position:0% +the cost of advertising but it's just +coke you know gets gets a huge market + + align:start position:0% +coke you know gets gets a huge market + + + align:start position:0% +coke you know gets gets a huge market +expands its market okay so now let's + + align:start position:0% +expands its market okay so now let's + + + align:start position:0% +expands its market okay so now let's +play the game + + align:start position:0% +play the game + + + align:start position:0% +play the game +well now let's say your coke you say + + align:start position:0% +well now let's say your coke you say + + + align:start position:0% +well now let's say your coke you say +well if I advertise if I advertise and + + align:start position:0% +well if I advertise if I advertise and + + + align:start position:0% +well if I advertise if I advertise and +Pepsi advertises I make three but if I + + align:start position:0% +Pepsi advertises I make three but if I + + + align:start position:0% +Pepsi advertises I make three but if I +don't advertising Pepsi advertises I + + align:start position:0% +don't advertising Pepsi advertises I + + + align:start position:0% +don't advertising Pepsi advertises I +make negative - so I should advertise if + + align:start position:0% +make negative - so I should advertise if + + + align:start position:0% +make negative - so I should advertise if +I advertise Pepsi doesn't advertise that + + align:start position:0% +I advertise Pepsi doesn't advertise that + + + align:start position:0% +I advertise Pepsi doesn't advertise that +make 13 if I if I don't advertise and + + align:start position:0% +make 13 if I if I don't advertise and + + + align:start position:0% +make 13 if I if I don't advertise and +Pepsi doesn't advertise I make eight so + + align:start position:0% +Pepsi doesn't advertise I make eight so + + + align:start position:0% +Pepsi doesn't advertise I make eight so +either way my dominant strategies to + + align:start position:0% +either way my dominant strategies to + + + align:start position:0% +either way my dominant strategies to +advertise and likewise Pepsi does the + + align:start position:0% +advertise and likewise Pepsi does the + + + align:start position:0% +advertise and likewise Pepsi does the +same thing it's actually I screwed up + + align:start position:0% +same thing it's actually I screwed up + + + align:start position:0% +same thing it's actually I screwed up +writing this compared to my notes but + + align:start position:0% +writing this compared to my notes but + + + align:start position:0% +writing this compared to my notes but +it's good because it shows + + align:start position:0% +it's good because it shows + + + align:start position:0% +it's good because it shows +you flip the matrix but the logic is the + + align:start position:0% +you flip the matrix but the logic is the + + + align:start position:0% +you flip the matrix but the logic is the +same it hopes you sort of not just + + align:start position:0% +same it hopes you sort of not just + + + align:start position:0% +same it hopes you sort of not just +memorize cells little a matrix but learn + + align:start position:0% +memorize cells little a matrix but learn + + + align:start position:0% +memorize cells little a matrix but learn +the logic the point is either way the + + align:start position:0% +the logic the point is either way the + + + align:start position:0% +the logic the point is either way the +dominant strategist to advertise so they + + align:start position:0% +dominant strategist to advertise so they + + + align:start position:0% +dominant strategist to advertise so they +both advertise so real-world example of + + align:start position:0% +both advertise so real-world example of + + + align:start position:0% +both advertise so real-world example of +how you can end up now so much Oh pepsin + + align:start position:0% +how you can end up now so much Oh pepsin + + + align:start position:0% +how you can end up now so much Oh pepsin +coke do this + + align:start position:0% +coke do this + + + align:start position:0% +coke do this +actually there was industry that did + + align:start position:0% +actually there was industry that did + + + align:start position:0% +actually there was industry that did +this so when I was a kid you never ever + + align:start position:0% +this so when I was a kid you never ever + + + align:start position:0% +this so when I was a kid you never ever +saw ads for liquor on TV + + align:start position:0% +saw ads for liquor on TV + + + align:start position:0% +saw ads for liquor on TV +there were beer ads and wine ads but no + + align:start position:0% +there were beer ads and wine ads but no + + + align:start position:0% +there were beer ads and wine ads but no +hard alcohol that no bourbon no whiskey + + align:start position:0% +hard alcohol that no bourbon no whiskey + + + align:start position:0% +hard alcohol that no bourbon no whiskey +no nothing gin all this always you know + + align:start position:0% +no nothing gin all this always you know + + + align:start position:0% +no nothing gin all this always you know +captain Morgan's ads we see now they + + align:start position:0% +captain Morgan's ads we see now they + + + align:start position:0% +captain Morgan's ads we see now they +didn't exist when I was a kid but it + + align:start position:0% +didn't exist when I was a kid but it + + + align:start position:0% +didn't exist when I was a kid but it +wasn't because the law it was because + + align:start position:0% +wasn't because the law it was because + + + align:start position:0% +wasn't because the law it was because +the hard liquor industry cooperatively + + align:start position:0% +the hard liquor industry cooperatively + + + align:start position:0% +the hard liquor industry cooperatively +agreed none that would advertise this + + align:start position:0% +agreed none that would advertise this + + + align:start position:0% +agreed none that would advertise this +actually imposed a cooperative Librium + + align:start position:0% +actually imposed a cooperative Librium + + + align:start position:0% +actually imposed a cooperative Librium +and then that broke down I don't know + + align:start position:0% +and then that broke down I don't know + + + align:start position:0% +and then that broke down I don't know +the story of how it broke down but + + align:start position:0% +the story of how it broke down but + + + align:start position:0% +the story of how it broke down but +something broke down now they all + + align:start position:0% +something broke down now they all + + + align:start position:0% +something broke down now they all +advertise and they're probably all worse + + align:start position:0% +advertise and they're probably all worse + + + align:start position:0% +advertise and they're probably all worse +off than they were when they just didn't + + align:start position:0% +off than they were when they just didn't + + + align:start position:0% +off than they were when they just didn't +advertise okay we'll talk next time + + align:start position:0% +advertise okay we'll talk next time + + + align:start position:0% +advertise okay we'll talk next time +about why it probably broke down I don't + + align:start position:0% +about why it probably broke down I don't + + + align:start position:0% +about why it probably broke down I don't +know the stories well I have a rough + + align:start position:0% +know the stories well I have a rough + + + align:start position:0% +know the stories well I have a rough +sense and I'll talk about that next time + + align:start position:0% +sense and I'll talk about that next time + + + align:start position:0% +sense and I'll talk about that next time +but this is the point of how a + + align:start position:0% +but this is the point of how a + + + align:start position:0% +but this is the point of how a +non-cooperative living can drive you to + + align:start position:0% +non-cooperative living can drive you to + + + align:start position:0% +non-cooperative living can drive you to +a bad outcome okay now basically this + + align:start position:0% +a bad outcome okay now basically this + + + align:start position:0% +a bad outcome okay now basically this +doesn't just apply to prisoners or + + align:start position:0% +doesn't just apply to prisoners or + + + align:start position:0% +doesn't just apply to prisoners or +business that applies to people too so + + align:start position:0% +business that applies to people too so + + + align:start position:0% +business that applies to people too so +let's say poor Hector back there is had + + align:start position:0% +let's say poor Hector back there is had + + + align:start position:0% +let's say poor Hector back there is had +a fight with his girlfriend okay and + + align:start position:0% +a fight with his girlfriend okay and + + + align:start position:0% +a fight with his girlfriend okay and +they've had a big fight they've been + + align:start position:0% +they've had a big fight they've been + + + align:start position:0% +they've had a big fight they've been +gone a little while they've had a big + + align:start position:0% +gone a little while they've had a big + + + align:start position:0% +gone a little while they've had a big +fight and Hector's got to decide do I + + align:start position:0% +fight and Hector's got to decide do I + + + align:start position:0% +fight and Hector's got to decide do I +apologize so don't wait for her to + + align:start position:0% +apologize so don't wait for her to + + + align:start position:0% +apologize so don't wait for her to +apologize okay + + align:start position:0% +apologize okay + + + align:start position:0% +apologize okay +well the last thing Hector wants is to + + align:start position:0% +well the last thing Hector wants is to + + + align:start position:0% +well the last thing Hector wants is to +go up there and apologize have mercy + + align:start position:0% +go up there and apologize have mercy + + + align:start position:0% +go up there and apologize have mercy +forget it I'm breaking up with you + + align:start position:0% +forget it I'm breaking up with you + + + align:start position:0% +forget it I'm breaking up with you +that'd be the worst okay if he knows + + align:start position:0% +that'd be the worst okay if he knows + + + align:start position:0% +that'd be the worst okay if he knows +she's gonna be like oh I'm sorry too + + align:start position:0% +she's gonna be like oh I'm sorry too + + + align:start position:0% +she's gonna be like oh I'm sorry too +then he'd be happy to do it but what if + + align:start position:0% +then he'd be happy to do it but what if + + + align:start position:0% +then he'd be happy to do it but what if +he goes she has no I'm breaking up with + + align:start position:0% +he goes she has no I'm breaking up with + + + align:start position:0% +he goes she has no I'm breaking up with +you will then and she's thinking the + + align:start position:0% +you will then and she's thinking the + + + align:start position:0% +you will then and she's thinking the +same thing so what happens they break up + + align:start position:0% +same thing so what happens they break up + + + align:start position:0% +same thing so what happens they break up +okay + + align:start position:0% +okay + + + align:start position:0% +okay +we've been through this many times in + + align:start position:0% +we've been through this many times in + + + align:start position:0% +we've been through this many times in +our lives this is the non-cooperative + + align:start position:0% +our lives this is the non-cooperative + + + align:start position:0% +our lives this is the non-cooperative +strategy okay basically if you don't the + + align:start position:0% +strategy okay basically if you don't the + + + align:start position:0% +strategy okay basically if you don't the +other person is gonna do your dominant + + align:start position:0% +other person is gonna do your dominant + + + align:start position:0% +other person is gonna do your dominant +strategies to be an okay and + + align:start position:0% +strategies to be an okay and + + + align:start position:0% +strategies to be an okay and +basically that happens a lot in the + + align:start position:0% +basically that happens a lot in the + + + align:start position:0% +basically that happens a lot in the +context of the real world okay + + align:start position:0% +context of the real world okay + + + align:start position:0% +context of the real world okay +so now we have this sort of sad sounding + + align:start position:0% +so now we have this sort of sad sounding + + + align:start position:0% +so now we have this sort of sad sounding +outcome that basically game theory leads + + align:start position:0% +outcome that basically game theory leads + + + align:start position:0% +outcome that basically game theory leads +to bad outcomes for producers at least + + align:start position:0% +to bad outcomes for producers at least + + + align:start position:0% +to bad outcomes for producers at least +but + + align:start position:0% +but + + + align:start position:0% +but +this is what's exciting about game + + align:start position:0% +this is what's exciting about game + + + align:start position:0% +this is what's exciting about game +theory so when I went to grad school + + align:start position:0% +theory so when I went to grad school + + + align:start position:0% +theory so when I went to grad school +back you know when dinosaurs roamed the + + align:start position:0% +back you know when dinosaurs roamed the + + + align:start position:0% +back you know when dinosaurs roamed the +earth game theory was sort of taught + + align:start position:0% +earth game theory was sort of taught + + + align:start position:0% +earth game theory was sort of taught +barely in the sequence it was sort of + + align:start position:0% +barely in the sequence it was sort of + + + align:start position:0% +barely in the sequence it was sort of +like an extra course taught a little bit + + align:start position:0% +like an extra course taught a little bit + + + align:start position:0% +like an extra course taught a little bit +now it sort of dominates the teaching of + + align:start position:0% +now it sort of dominates the teaching of + + + align:start position:0% +now it sort of dominates the teaching of +microeconomics in economics and it + + align:start position:0% +microeconomics in economics and it + + + align:start position:0% +microeconomics in economics and it +doesn't dominate but it's a whole like + + align:start position:0% +doesn't dominate but it's a whole like + + + align:start position:0% +doesn't dominate but it's a whole like +component of our core microeconomics + + align:start position:0% +component of our core microeconomics + + + align:start position:0% +component of our core microeconomics +education because it's given such a cool + + align:start position:0% +education because it's given such a cool + + + align:start position:0% +education because it's given such a cool +set of tools to think about these + + align:start position:0% +set of tools to think about these + + + align:start position:0% +set of tools to think about these +decisions now I can't give you even 1% + + align:start position:0% +decisions now I can't give you even 1% + + + align:start position:0% +decisions now I can't give you even 1% +of the flavor of game theory if you want + + align:start position:0% +of the flavor of game theory if you want + + + align:start position:0% +of the flavor of game theory if you want +to learn more I highly suggest you take + + align:start position:0% +to learn more I highly suggest you take + + + align:start position:0% +to learn more I highly suggest you take +1412 which is our game theory class and + + align:start position:0% +1412 which is our game theory class and + + + align:start position:0% +1412 which is our game theory class and +you can learn a ton but let me use sort + + align:start position:0% +you can learn a ton but let me use sort + + + align:start position:0% +you can learn a ton but let me use sort +of one interesting wrinkle of the kind + + align:start position:0% +of one interesting wrinkle of the kind + + + align:start position:0% +of one interesting wrinkle of the kind +of things game theory can do to go + + align:start position:0% +of things game theory can do to go + + + align:start position:0% +of things game theory can do to go +beyond this and that's to imagine that + + align:start position:0% +beyond this and that's to imagine that + + + align:start position:0% +beyond this and that's to imagine that +Coke and Pepsi are not playing a + + align:start position:0% +Coke and Pepsi are not playing a + + + align:start position:0% +Coke and Pepsi are not playing a +one-shot game but a repeated game + + align:start position:0% + + + + align:start position:0% + +repeated game ok so now imagine that um + + align:start position:0% +repeated game ok so now imagine that um + + + align:start position:0% +repeated game ok so now imagine that um +coke says to Pepsi the following I + + align:start position:0% +coke says to Pepsi the following I + + + align:start position:0% +coke says to Pepsi the following I +promise to not advertise as long as you + + align:start position:0% +promise to not advertise as long as you + + + align:start position:0% +promise to not advertise as long as you +don't advertise but if you ever + + align:start position:0% +don't advertise but if you ever + + + align:start position:0% +don't advertise but if you ever +advertise I will advertise forever ok + + align:start position:0% +advertise I will advertise forever ok + + + align:start position:0% +advertise I will advertise forever ok +coke system FC I promise not to + + align:start position:0% +coke system FC I promise not to + + + align:start position:0% +coke system FC I promise not to +advertise as long as you don't advertise + + align:start position:0% +advertise as long as you don't advertise + + + align:start position:0% +advertise as long as you don't advertise +but if I ever catch you advertising I'm + + align:start position:0% +but if I ever catch you advertising I'm + + + align:start position:0% +but if I ever catch you advertising I'm +gonna advertise forever ok so now a + + align:start position:0% +gonna advertise forever ok so now a + + + align:start position:0% +gonna advertise forever ok so now a +match think about Pepsi's choice in + + align:start position:0% +match think about Pepsi's choice in + + + align:start position:0% +match think about Pepsi's choice in +period one Pepsi is choice in period 1 + + align:start position:0% +period one Pepsi is choice in period 1 + + + align:start position:0% +period one Pepsi is choice in period 1 +impaired 1 they could say ha stupid coke + + align:start position:0% +impaired 1 they could say ha stupid coke + + + align:start position:0% +impaired 1 they could say ha stupid coke +I'm gonna jump on them and advertise + + align:start position:0% +I'm gonna jump on them and advertise + + + align:start position:0% +I'm gonna jump on them and advertise +they promised me I could advertise I'm + + align:start position:0% +they promised me I could advertise I'm + + + align:start position:0% +they promised me I could advertise I'm +gonna make so Pepsi advertises they're + + align:start position:0% +gonna make so Pepsi advertises they're + + + align:start position:0% +gonna make so Pepsi advertises they're +gonna make 13 in period 1 right because + + align:start position:0% +gonna make 13 in period 1 right because + + + align:start position:0% +gonna make 13 in period 1 right because +cokes taking themselves off to the side + + align:start position:0% +cokes taking themselves off to the side + + + align:start position:0% +cokes taking themselves off to the side +but after period 1 they're gonna make 8 + + align:start position:0% +but after period 1 they're gonna make 8 + + + align:start position:0% +but after period 1 they're gonna make 8 +forever + + align:start position:0% +forever + + + align:start position:0% +forever +no they're gonna sorry they're gonna + + align:start position:0% +no they're gonna sorry they're gonna + + + align:start position:0% +no they're gonna sorry they're gonna +make three forever because cokes can + + align:start position:0% +make three forever because cokes can + + + align:start position:0% +make three forever because cokes can +advertise they're gonna advertise they + + align:start position:0% +advertise they're gonna advertise they + + + align:start position:0% +advertise they're gonna advertise they +break down to the non-cooperative + + align:start position:0% +break down to the non-cooperative + + + align:start position:0% +break down to the non-cooperative +equilibrium ok + + align:start position:0% +equilibrium ok + + + align:start position:0% +equilibrium ok +if Pepsi advertise now what if Pepsi + + align:start position:0% +if Pepsi advertise now what if Pepsi + + + align:start position:0% +if Pepsi advertise now what if Pepsi +doesn't advertise as well as it doesn't + + align:start position:0% +doesn't advertise as well as it doesn't + + + align:start position:0% +doesn't advertise as well as it doesn't +advertise then it gets to deal with Coke + + align:start position:0% +advertise then it gets to deal with Coke + + + align:start position:0% +advertise then it gets to deal with Coke +so it makes eight forever so now we'll + + align:start position:0% +so it makes eight forever so now we'll + + + align:start position:0% +so it makes eight forever so now we'll +talk later in the course about how you + + align:start position:0% +talk later in the course about how you + + + align:start position:0% +talk later in the course about how you +my numbers that happen different times + + align:start position:0% +my numbers that happen different times + + + align:start position:0% +my numbers that happen different times +to trust me a forever is a way better + + align:start position:0% +to trust me a forever is a way better + + + align:start position:0% +to trust me a forever is a way better +deal Don thirteen and three forever okay + + align:start position:0% +deal Don thirteen and three forever okay + + + align:start position:0% +deal Don thirteen and three forever okay +so actually by having this be a repeated + + align:start position:0% +so actually by having this be a repeated + + + align:start position:0% +so actually by having this be a repeated +game coke has solved the prisoner's + + align:start position:0% +game coke has solved the prisoner's + + + align:start position:0% +game coke has solved the prisoner's +dilemma it's essentially imposed a + + align:start position:0% +dilemma it's essentially imposed a + + + align:start position:0% +dilemma it's essentially imposed a +cooperative equilibrium on the problem + + align:start position:0% +cooperative equilibrium on the problem + + + align:start position:0% +cooperative equilibrium on the problem +okay so that's how a repeated game can + + align:start position:0% +okay so that's how a repeated game can + + + align:start position:0% +okay so that's how a repeated game can +fix this but as we're getting through it + + align:start position:0% +fix this but as we're getting through it + + + align:start position:0% +fix this but as we're getting through it +gets really exciting that only works if + + align:start position:0% +gets really exciting that only works if + + + align:start position:0% +gets really exciting that only works if +this game never ends because once Coke + + align:start position:0% +this game never ends because once Coke + + + align:start position:0% +this game never ends because once Coke +or Pepsi thinks there's an end to the + + align:start position:0% +or Pepsi thinks there's an end to the + + + align:start position:0% +or Pepsi thinks there's an end to the +game the entire thing breaks down okay + + align:start position:0% +game the entire thing breaks down okay + + + align:start position:0% +game the entire thing breaks down okay +so imagine for example the coke makes + + align:start position:0% +so imagine for example the coke makes + + + align:start position:0% +so imagine for example the coke makes +the offer to Pepsi but Pepsi's worried + + align:start position:0% +the offer to Pepsi but Pepsi's worried + + + align:start position:0% +the offer to Pepsi but Pepsi's worried +that in 10 years the government's going + + align:start position:0% +that in 10 years the government's going + + + align:start position:0% +that in 10 years the government's going +to outlaw soda okay + + align:start position:0% +to outlaw soda okay + + + align:start position:0% +to outlaw soda okay +the government you know has said look + + align:start position:0% +the government you know has said look + + + align:start position:0% +the government you know has said look +we're heading that direction so does + + align:start position:0% +we're heading that direction so does + + + align:start position:0% +we're heading that direction so does +gonna be legal in 10 years so I don't + + align:start position:0% +gonna be legal in 10 years so I don't + + + align:start position:0% +gonna be legal in 10 years so I don't +want to do this + + align:start position:0% +want to do this + + + align:start position:0% +want to do this +so in that case know that I'm sorry not + + align:start position:0% +so in that case know that I'm sorry not + + + align:start position:0% +so in that case know that I'm sorry not +that I want to I so I have that in my + + align:start position:0% +that I want to I so I have that in my + + + align:start position:0% +that I want to I so I have that in my +mind so Coke offers the deal now what do + + align:start position:0% +mind so Coke offers the deal now what do + + + align:start position:0% +mind so Coke offers the deal now what do +I think well let's think about Pepsi's + + align:start position:0% +I think well let's think about Pepsi's + + + align:start position:0% +I think well let's think about Pepsi's +decision in the ninth year they've made + + align:start position:0% +decision in the ninth year they've made + + + align:start position:0% +decision in the ninth year they've made +eight eight eight eight eight and they + + align:start position:0% +eight eight eight eight eight and they + + + align:start position:0% +eight eight eight eight eight and they +get to your nine now in year nine they + + align:start position:0% +get to your nine now in year nine they + + + align:start position:0% +get to your nine now in year nine they +know that next year there's no more game + + align:start position:0% +know that next year there's no more game + + + align:start position:0% +know that next year there's no more game +so what should they do advertise grab + + align:start position:0% +so what should they do advertise grab + + + align:start position:0% +so what should they do advertise grab +the thirteen in the last period because + + align:start position:0% +the thirteen in the last period because + + + align:start position:0% +the thirteen in the last period because +Coke can't punish them because the + + align:start position:0% +Coke can't punish them because the + + + align:start position:0% +Coke can't punish them because the +game's over + + align:start position:0% +game's over + + + align:start position:0% +game's over +but Coke knows this so it's Coke gonna + + align:start position:0% +but Coke knows this so it's Coke gonna + + + align:start position:0% +but Coke knows this so it's Coke gonna +do in the ninth year advertise its can + + align:start position:0% +do in the ninth year advertise its can + + + align:start position:0% +do in the ninth year advertise its can +advertise so they're both gonna make so + + align:start position:0% +advertise so they're both gonna make so + + + align:start position:0% +advertise so they're both gonna make so +so they're both gonna make a three + + align:start position:0% +so they're both gonna make a three + + + align:start position:0% +so they're both gonna make a three +well if Pepsi knows cokes can advertise + + align:start position:0% +well if Pepsi knows cokes can advertise + + + align:start position:0% +well if Pepsi knows cokes can advertise +than that ninth year no matter what + + align:start position:0% +than that ninth year no matter what + + + align:start position:0% +than that ninth year no matter what +what's your pet's you in the eighth year + + align:start position:0% +what's your pet's you in the eighth year + + + align:start position:0% +what's your pet's you in the eighth year +advertise and if Coke knows pets can + + align:start position:0% +advertise and if Coke knows pets can + + + align:start position:0% +advertise and if Coke knows pets can +advertise an eighth year bunch of coke + + align:start position:0% +advertise an eighth year bunch of coke + + + align:start position:0% +advertise an eighth year bunch of coke +do and so on and ends up that they both + + align:start position:0% +do and so on and ends up that they both + + + align:start position:0% +do and so on and ends up that they both +advertise all the way through so the + + align:start position:0% +advertise all the way through so the + + + align:start position:0% +advertise all the way through so the +game breaks down if it's an end this is + + align:start position:0% +game breaks down if it's an end this is + + + align:start position:0% +game breaks down if it's an end this is +really kind of neat and this is what + + align:start position:0% +really kind of neat and this is what + + + align:start position:0% +really kind of neat and this is what +game through is all about is how do you + + align:start position:0% +game through is all about is how do you + + + align:start position:0% +game through is all about is how do you +think through these more complicated + + align:start position:0% +think through these more complicated + + + align:start position:0% +think through these more complicated +scenarios that are much more complicated + + align:start position:0% +scenarios that are much more complicated + + + align:start position:0% +scenarios that are much more complicated +the prisoner's dilemma and actually + + align:start position:0% +the prisoner's dilemma and actually + + + align:start position:0% +the prisoner's dilemma and actually +think about how firms and individuals + + align:start position:0% +think about how firms and individuals + + + align:start position:0% +think about how firms and individuals +might actually behave yeah + + align:start position:0% + + + + align:start position:0% + +these contracts + + align:start position:0% +these contracts + + + align:start position:0% +these contracts +earlier sure that's much and once again + + align:start position:0% +earlier sure that's much and once again + + + align:start position:0% +earlier sure that's much and once again +that's exact that's what you cover in a + + align:start position:0% +that's exact that's what you cover in a + + + align:start position:0% +that's exact that's what you cover in a +field of course like game theories what + + align:start position:0% +field of course like game theories what + + + align:start position:0% +field of course like game theories what +about alternative forms of contracting + + align:start position:0% +about alternative forms of contracting + + + align:start position:0% +about alternative forms of contracting +with exclusionary contractor what we + + align:start position:0% +with exclusionary contractor what we + + + align:start position:0% +with exclusionary contractor what we +call tying in contracting that's great + + align:start position:0% +call tying in contracting that's great + + + align:start position:0% +call tying in contracting that's great +and they would but that's that's why you + + align:start position:0% +and they would but that's that's why you + + + align:start position:0% +and they would but that's that's why you +got to take 1412 okay yeah + + align:start position:0% + + + + align:start position:0% + +like + + align:start position:0% + + + + align:start position:0% + +yeah the way I've set this problem up if + + align:start position:0% +yeah the way I've set this problem up if + + + align:start position:0% +yeah the way I've set this problem up if +they could commit to that that'd be + + align:start position:0% +they could commit to that that'd be + + + align:start position:0% +they could commit to that that'd be +right but you'd have to commit to it + + align:start position:0% +right but you'd have to commit to it + + + align:start position:0% +right but you'd have to commit to it +because then the funds the period the + + align:start position:0% +because then the funds the period the + + + align:start position:0% +because then the funds the period the +period the Pepsi promised to take off if + + align:start position:0% +period the Pepsi promised to take off if + + + align:start position:0% +period the Pepsi promised to take off if +they actually advertised that period + + align:start position:0% +they actually advertised that period + + + align:start position:0% +they actually advertised that period +then cokes screwed so that would work as + + align:start position:0% +then cokes screwed so that would work as + + + align:start position:0% +then cokes screwed so that would work as +a repeated game solution but it wouldn't + + align:start position:0% +a repeated game solution but it wouldn't + + + align:start position:0% +a repeated game solution but it wouldn't +work as a as a non repeated game so as + + align:start position:0% +work as a as a non repeated game so as + + + align:start position:0% +work as a as a non repeated game so as +again as the work is an infinite + + align:start position:0% +again as the work is an infinite + + + align:start position:0% +again as the work is an infinite +repeated game but not a non infinite + + align:start position:0% +repeated game but not a non infinite + + + align:start position:0% +repeated game but not a non infinite +repeated game okay + + align:start position:0% +repeated game okay + + + align:start position:0% +repeated game okay +good question okay other questions all + + align:start position:0% +good question okay other questions all + + + align:start position:0% +good question okay other questions all +right so that's the basic game theory + + align:start position:0% +right so that's the basic game theory + + + align:start position:0% +right so that's the basic game theory +that's just a taste for the excitement + + align:start position:0% +that's just a taste for the excitement + + + align:start position:0% +that's just a taste for the excitement +that you can live with game theory but + + align:start position:0% +that you can live with game theory but + + + align:start position:0% +that you can live with game theory but +in fact in economics we like to write + + align:start position:0% +in fact in economics we like to write + + + align:start position:0% +in fact in economics we like to write +that these fun examples but we really + + align:start position:0% +that these fun examples but we really + + + align:start position:0% +that these fun examples but we really +prefer to do math so let's actually + + align:start position:0% +prefer to do math so let's actually + + + align:start position:0% +prefer to do math so let's actually +think about the math of how we take game + + align:start position:0% +think about the math of how we take game + + + align:start position:0% +think about the math of how we take game +theory concepts and put them in practice + + align:start position:0% +theory concepts and put them in practice + + + align:start position:0% +theory concepts and put them in practice +and that's we that the way we do that is + + align:start position:0% +and that's we that the way we do that is + + + align:start position:0% +and that's we that the way we do that is +through the concept of the cournot model + + align:start position:0% + + + + align:start position:0% + +the cournot model of non cooperative + + align:start position:0% +the cournot model of non cooperative + + + align:start position:0% +the cournot model of non cooperative +oligopolies okay so it's the cournot + + align:start position:0% +oligopolies okay so it's the cournot + + + align:start position:0% +oligopolies okay so it's the cournot +model of non cooperative oligopoly is + + align:start position:0% +model of non cooperative oligopoly is + + + align:start position:0% +model of non cooperative oligopoly is +the standard workhorse model takes this + + align:start position:0% +the standard workhorse model takes this + + + align:start position:0% +the standard workhorse model takes this +intuition and puts it into the kind of + + align:start position:0% +intuition and puts it into the kind of + + + align:start position:0% +intuition and puts it into the kind of +optimizing math we've been doing this so + + align:start position:0% +optimizing math we've been doing this so + + + align:start position:0% +optimizing math we've been doing this so +far this class okay so let's now let's + + align:start position:0% +far this class okay so let's now let's + + + align:start position:0% +far this class okay so let's now let's +imagine non cooperative case but now + + align:start position:0% +imagine non cooperative case but now + + + align:start position:0% +imagine non cooperative case but now +let's imagine there's not just two + + align:start position:0% +let's imagine there's not just two + + + align:start position:0% +let's imagine there's not just two +choices but realistically there's a + + align:start position:0% +choices but realistically there's a + + + align:start position:0% +choices but realistically there's a +whole set of choices okay then how would + + align:start position:0% +whole set of choices okay then how would + + + align:start position:0% +whole set of choices okay then how would +you behave in the in that case so let's + + align:start position:0% +you behave in the in that case so let's + + + align:start position:0% +you behave in the in that case so let's +imagine that there's two airlines United + + align:start position:0% +imagine that there's two airlines United + + + align:start position:0% +imagine that there's two airlines United +in American United America two so we're + + align:start position:0% +in American United America two so we're + + + align:start position:0% +in American United America two so we're +gonna have a oligopolistic to firm + + align:start position:0% +gonna have a oligopolistic to firm + + + align:start position:0% +gonna have a oligopolistic to firm +airline industry obviously the math can + + align:start position:0% +airline industry obviously the math can + + + align:start position:0% +airline industry obviously the math can +extend to more firms but just to start + + align:start position:0% +extend to more firms but just to start + + + align:start position:0% +extend to more firms but just to start +now and I'll talk about that next + + align:start position:0% +now and I'll talk about that next + + + align:start position:0% +now and I'll talk about that next +lecture but for now imagine a two firm + + align:start position:0% +lecture but for now imagine a two firm + + + align:start position:0% +lecture but for now imagine a two firm +industry United an American and because + + align:start position:0% +industry United an American and because + + + align:start position:0% +industry United an American and because +the hub-and-spoke system we discussed + + align:start position:0% +the hub-and-spoke system we discussed + + + align:start position:0% +the hub-and-spoke system we discussed +last time let's imagine of the only two + + align:start position:0% +last time let's imagine of the only two + + + align:start position:0% +last time let's imagine of the only two +folks that go from Boston Chicago okay + + align:start position:0% +folks that go from Boston Chicago okay + + + align:start position:0% +folks that go from Boston Chicago okay +because this hub-and-spoke system the + + align:start position:0% +because this hub-and-spoke system the + + + align:start position:0% +because this hub-and-spoke system the +only folks to go from Boston Chicago at + + align:start position:0% +only folks to go from Boston Chicago at + + + align:start position:0% +only folks to go from Boston Chicago at +night in America and they do in fact + + align:start position:0% +night in America and they do in fact + + + align:start position:0% +night in America and they do in fact +dominate that line so let's imagine the + + align:start position:0% +dominate that line so let's imagine the + + + align:start position:0% +dominate that line so let's imagine the +only folks and say no other firms could + + align:start position:0% +only folks and say no other firms could + + + align:start position:0% +only folks and say no other firms could +get peed in this and this on this route + + align:start position:0% +get peed in this and this on this route + + + align:start position:0% +get peed in this and this on this route +because they can't get slots at the + + align:start position:0% +because they can't get slots at the + + + align:start position:0% +because they can't get slots at the +airport so the question is how do these + + align:start position:0% +airport so the question is how do these + + + align:start position:0% +airport so the question is how do these +firms decide how many flights to run + + align:start position:0% +firms decide how many flights to run + + + align:start position:0% +firms decide how many flights to run +it's not just advertised don't it's + + align:start position:0% +it's not just advertised don't it's + + + align:start position:0% +it's not just advertised don't it's +literally a continuous decision of how + + align:start position:0% +literally a continuous decision of how + + + align:start position:0% +literally a continuous decision of how +many flights to run every day and how + + align:start position:0% +many flights to run every day and how + + + align:start position:0% +many flights to run every day and how +much to charge + + align:start position:0% +much to charge + + + align:start position:0% +much to charge +okay they've got to make that decision + + align:start position:0% +okay they've got to make that decision + + + align:start position:0% +okay they've got to make that decision +and the Nash equilibrium here we call a + + align:start position:0% +and the Nash equilibrium here we call a + + + align:start position:0% +and the Nash equilibrium here we call a +core know the sort of subset of Nash for + + align:start position:0% +core know the sort of subset of Nash for + + + align:start position:0% +core know the sort of subset of Nash for +this examples called the cournot + + align:start position:0% +this examples called the cournot + + + align:start position:0% +this examples called the cournot +equilibrium and the cournot equilibrium + + align:start position:0% +equilibrium and the cournot equilibrium + + + align:start position:0% +equilibrium and the cournot equilibrium +exists when a firm chooses a quantity + + align:start position:0% +exists when a firm chooses a quantity + + + align:start position:0% +exists when a firm chooses a quantity +such that given the quantity chosen by + + align:start position:0% +such that given the quantity chosen by + + + align:start position:0% +such that given the quantity chosen by +the other firm they don't want to change + + align:start position:0% +the other firm they don't want to change + + + align:start position:0% +the other firm they don't want to change +so a firm chooses essentially the profit + + align:start position:0% +so a firm chooses essentially the profit + + + align:start position:0% +so a firm chooses essentially the profit +maximizing quantity given the quantity + + align:start position:0% +maximizing quantity given the quantity + + + align:start position:0% +maximizing quantity given the quantity +chosen by the other firm okay and if + + align:start position:0% +chosen by the other firm okay and if + + + align:start position:0% +chosen by the other firm okay and if +that profit maximizing quantity okay + + align:start position:0% +that profit maximizing quantity okay + + + align:start position:0% +that profit maximizing quantity okay +then that you're in cournot equilibrium + + align:start position:0% +then that you're in cournot equilibrium + + + align:start position:0% +then that you're in cournot equilibrium +if you have chosen a quantity that is + + align:start position:0% +if you have chosen a quantity that is + + + align:start position:0% +if you have chosen a quantity that is +profit maximizing given what the other + + align:start position:0% +profit maximizing given what the other + + + align:start position:0% +profit maximizing given what the other +firm is doing okay so basically how do + + align:start position:0% +firm is doing okay so basically how do + + + align:start position:0% +firm is doing okay so basically how do +we how do we actually carry this out + + align:start position:0% +we how do we actually carry this out + + + align:start position:0% +we how do we actually carry this out +okay let's talk about the steps okay so + + align:start position:0% +okay let's talk about the steps okay so + + + align:start position:0% +okay let's talk about the steps okay so +the first step here's I'm going to talk + + align:start position:0% +the first step here's I'm going to talk + + + align:start position:0% +the first step here's I'm going to talk +intuitively about the math what we're + + align:start position:0% +intuitively about the math what we're + + + align:start position:0% +intuitively about the math what we're +gonna do and I'm gonna talk + + align:start position:0% +gonna do and I'm gonna talk + + + align:start position:0% +gonna do and I'm gonna talk +mathematically and graphically we + + align:start position:0% +mathematically and graphically we + + + align:start position:0% +mathematically and graphically we +actually do they're essentially three + + align:start position:0% +actually do they're essentially three + + + align:start position:0% +actually do they're essentially three +steps in solving for the cournot + + align:start position:0% +steps in solving for the cournot + + + align:start position:0% +steps in solving for the cournot +equilibrium the first is ask how your + + align:start position:0% +equilibrium the first is ask how your + + + align:start position:0% +equilibrium the first is ask how your +demand changes when some of its absorbed + + align:start position:0% +demand changes when some of its absorbed + + + align:start position:0% +demand changes when some of its absorbed +by other firms so the first is solve for + + align:start position:0% +by other firms so the first is solve for + + + align:start position:0% +by other firms so the first is solve for +your residual demand function what does + + align:start position:0% +your residual demand function what does + + + align:start position:0% +your residual demand function what does +your demand curve look like given what + + align:start position:0% +your demand curve look like given what + + + align:start position:0% +your demand curve look like given what +the other firm does that's step one step + + align:start position:0% +the other firm does that's step one step + + + align:start position:0% +the other firm does that's step one step +two is that you develop a marginal + + align:start position:0% +two is that you develop a marginal + + + align:start position:0% +two is that you develop a marginal +revenue which is a function of the other + + align:start position:0% +revenue which is a function of the other + + + align:start position:0% +revenue which is a function of the other +firms quantity little Q it's multiple + + align:start position:0% +firms quantity little Q it's multiple + + + align:start position:0% +firms quantity little Q it's multiple +firms okay the other firms that's really + + align:start position:0% +firms okay the other firms that's really + + + align:start position:0% +firms okay the other firms that's really +bad hard to read the other firm's + + align:start position:0% +bad hard to read the other firm's + + + align:start position:0% +bad hard to read the other firm's +quantity so it's your marginal revenue + + align:start position:0% +quantity so it's your marginal revenue + + + align:start position:0% +quantity so it's your marginal revenue +function typically it's a function I'm + + align:start position:0% +function typically it's a function I'm + + + align:start position:0% +function typically it's a function I'm +sorry of both your quantity and the + + align:start position:0% +sorry of both your quantity and the + + + align:start position:0% +sorry of both your quantity and the +other firm's quantity a function of both + + align:start position:0% +other firm's quantity a function of both + + + align:start position:0% +other firm's quantity a function of both +your quantity and the other firm's + + align:start position:0% +your quantity and the other firm's + + + align:start position:0% +your quantity and the other firm's +quantity we developed marginal revenues + + align:start position:0% +quantity we developed marginal revenues + + + align:start position:0% +quantity we developed marginal revenues +as a function of your own quantity we + + align:start position:0% +as a function of your own quantity we + + + align:start position:0% +as a function of your own quantity we +know how to do that now we're developing + + align:start position:0% +know how to do that now we're developing + + + align:start position:0% +know how to do that now we're developing +our job as a function of your quantity + + align:start position:0% +our job as a function of your quantity + + + align:start position:0% +our job as a function of your quantity +and the other firm's quantity then you + + align:start position:0% +and the other firm's quantity then you + + + align:start position:0% +and the other firm's quantity then you +simply set this marginal revenue equal + + align:start position:0% +simply set this marginal revenue equal + + + align:start position:0% +simply set this marginal revenue equal +to marginal cost and that delivers you a + + align:start position:0% +to marginal cost and that delivers you a + + + align:start position:0% +to marginal cost and that delivers you a +conditional answer that delivers you + + align:start position:0% +conditional answer that delivers you + + + align:start position:0% +conditional answer that delivers you +your optimal quantity as a function of + + align:start position:0% +your optimal quantity as a function of + + + align:start position:0% +your optimal quantity as a function of +the other + + align:start position:0% +the other + + + align:start position:0% +the other +firms quanti okay + + align:start position:0% +firms quanti okay + + + align:start position:0% +firms quanti okay +well that doesn't do it's a whole lot of + + align:start position:0% +well that doesn't do it's a whole lot of + + + align:start position:0% +well that doesn't do it's a whole lot of +good except there's two firms so the + + align:start position:0% +good except there's two firms so the + + + align:start position:0% +good except there's two firms so the +fourth step is we do the same thing for + + align:start position:0% +fourth step is we do the same thing for + + + align:start position:0% +fourth step is we do the same thing for +the other firm and get the same kind of + + align:start position:0% +the other firm and get the same kind of + + + align:start position:0% +the other firm and get the same kind of +equation then what do we have two + + align:start position:0% +equation then what do we have two + + + align:start position:0% +equation then what do we have two +equations and two unknowns so we solve + + align:start position:0% + + + + align:start position:0% + +okay so what we do here is essentially + + align:start position:0% +okay so what we do here is essentially + + + align:start position:0% +okay so what we do here is essentially +the same thing we did before but now + + align:start position:0% +the same thing we did before but now + + + align:start position:0% +the same thing we did before but now +your marginal revenue is not just a + + align:start position:0% +your marginal revenue is not just a + + + align:start position:0% +your marginal revenue is not just a +function of your own clients a function + + align:start position:0% +function of your own clients a function + + + align:start position:0% +function of your own clients a function +the other guy's quantity same with the + + align:start position:0% +the other guy's quantity same with the + + + align:start position:0% +the other guy's quantity same with the +other guy that gives you two equations + + align:start position:0% +other guy that gives you two equations + + + align:start position:0% +other guy that gives you two equations +two unknowns we solve and the point at + + align:start position:0% +two unknowns we solve and the point at + + + align:start position:0% +two unknowns we solve and the point at +which both firms are happy is the + + align:start position:0% +which both firms are happy is the + + + align:start position:0% +which both firms are happy is the +cournot equilibrium okay + + align:start position:0% +cournot equilibrium okay + + + align:start position:0% +cournot equilibrium okay +so let's actually that's confusing so + + align:start position:0% +so let's actually that's confusing so + + + align:start position:0% +so let's actually that's confusing so +let's actually look at that let's start + + align:start position:0% +let's actually look at that let's start + + + align:start position:0% +let's actually look at that let's start +we'll do suppose graphically and + + align:start position:0% +we'll do suppose graphically and + + + align:start position:0% +we'll do suppose graphically and +mathematically let's start with figure + + align:start position:0% +mathematically let's start with figure + + + align:start position:0% +mathematically let's start with figure +thirteen one okay to make things easy + + align:start position:0% +thirteen one okay to make things easy + + + align:start position:0% +thirteen one okay to make things easy +let's start by imagining then American + + align:start position:0% +let's start by imagining then American + + + align:start position:0% +let's start by imagining then American +Airlines is a monopoly let's start with + + align:start position:0% +Airlines is a monopoly let's start with + + + align:start position:0% +Airlines is a monopoly let's start with +the world with them American Airlines + + align:start position:0% +the world with them American Airlines + + + align:start position:0% +the world with them American Airlines +monopoly okay and let's say that the + + align:start position:0% +monopoly okay and let's say that the + + + align:start position:0% +monopoly okay and let's say that the +demand function is P equals 339 minus Q + + align:start position:0% +demand function is P equals 339 minus Q + + + align:start position:0% +demand function is P equals 339 minus Q +that's an Amman for flights from Boston + + align:start position:0% +that's an Amman for flights from Boston + + + align:start position:0% +that's an Amman for flights from Boston +to Chicago okay and let's say that the + + align:start position:0% +to Chicago okay and let's say that the + + + align:start position:0% +to Chicago okay and let's say that the +marginal cost to make life easy I could + + align:start position:0% +marginal cost to make life easy I could + + + align:start position:0% +marginal cost to make life easy I could +have a cost function make your life + + align:start position:0% +have a cost function make your life + + + align:start position:0% +have a cost function make your life +difficult but maybe someday I'll do that + + align:start position:0% +difficult but maybe someday I'll do that + + + align:start position:0% +difficult but maybe someday I'll do that +but for now to make your life easy + + align:start position:0% +but for now to make your life easy + + + align:start position:0% +but for now to make your life easy +let's just say there's a flat marginal + + align:start position:0% +let's just say there's a flat marginal + + + align:start position:0% +let's just say there's a flat marginal +cost of 147 dollars okay I'm not gonna + + align:start position:0% +cost of 147 dollars okay I'm not gonna + + + align:start position:0% +cost of 147 dollars okay I'm not gonna +laugh or not gonna make life difficult + + align:start position:0% +laugh or not gonna make life difficult + + + align:start position:0% +laugh or not gonna make life difficult +with solving for marginal cost functions + + align:start position:0% +with solving for marginal cost functions + + + align:start position:0% +with solving for marginal cost functions +for now it's just him a flat marginal + + align:start position:0% +for now it's just him a flat marginal + + + align:start position:0% +for now it's just him a flat marginal +cost of 147 no matter how many flights + + align:start position:0% +cost of 147 no matter how many flights + + + align:start position:0% +cost of 147 no matter how many flights +they do its $147 per passenger so if + + align:start position:0% +they do its $147 per passenger so if + + + align:start position:0% +they do its $147 per passenger so if +your monopolist how do you solve this + + align:start position:0% +your monopolist how do you solve this + + + align:start position:0% +your monopolist how do you solve this +problem + + align:start position:0% +problem + + + align:start position:0% +problem +well first you derive your marginal + + align:start position:0% +well first you derive your marginal + + + align:start position:0% +well first you derive your marginal +revenue function + + align:start position:0% +revenue function + + + align:start position:0% +revenue function +well what's marginal revenue function + + align:start position:0% +well what's marginal revenue function + + + align:start position:0% +well what's marginal revenue function +well revenues is P times Q which is 339 + + align:start position:0% +well revenues is P times Q which is 339 + + + align:start position:0% +well revenues is P times Q which is 339 +Q minus Q squared so your marginal + + align:start position:0% +Q minus Q squared so your marginal + + + align:start position:0% +Q minus Q squared so your marginal +revenue function is 339 minus 2q + + align:start position:0% +revenue function is 339 minus 2q + + + align:start position:0% +revenue function is 339 minus 2q +that's your marver to reginal function + + align:start position:0% +that's your marver to reginal function + + + align:start position:0% +that's your marver to reginal function +if you're the monopolist what's your + + align:start position:0% +if you're the monopolist what's your + + + align:start position:0% +if you're the monopolist what's your +marginal cost well already said it's 147 + + align:start position:0% +marginal cost well already said it's 147 + + + align:start position:0% +marginal cost well already said it's 147 +and then you just solve and when you + + align:start position:0% +and then you just solve and when you + + + align:start position:0% +and then you just solve and when you +solve that you get the Q the optimal + + align:start position:0% +solve that you get the Q the optimal + + + align:start position:0% +solve that you get the Q the optimal +quantity is 96 flights and then how do + + align:start position:0% +quantity is 96 flights and then how do + + + align:start position:0% +quantity is 96 flights and then how do +you get the price how do you get the + + align:start position:0% +you get the price how do you get the + + + align:start position:0% +you get the price how do you get the +price of an awfully problem how do we + + align:start position:0% +price of an awfully problem how do we + + + align:start position:0% +price of an awfully problem how do we +know what the what the price is + + align:start position:0% +know what the what the price is + + + align:start position:0% +know what the what the price is +yeah you're gonna plug it back into the + + align:start position:0% +yeah you're gonna plug it back into the + + + align:start position:0% +yeah you're gonna plug it back into the +demand curve you got to take that + + align:start position:0% +demand curve you got to take that + + + align:start position:0% +demand curve you got to take that +quantity plug it back to the main curve + + align:start position:0% +quantity plug it back to the main curve + + + align:start position:0% +quantity plug it back to the main curve +so the price is 339 minus 96 or 243 okay + + align:start position:0% +so the price is 339 minus 96 or 243 okay + + + align:start position:0% +so the price is 339 minus 96 or 243 okay +so I just solved the monopoly problem + + align:start position:0% +so I just solved the monopoly problem + + + align:start position:0% +so I just solved the monopoly problem +quickly but that's um but that's what we + + align:start position:0% +quickly but that's um but that's what we + + + align:start position:0% +quickly but that's um but that's what we +did what we've done already in this + + align:start position:0% +did what we've done already in this + + + align:start position:0% +did what we've done already in this +class and you could see that in the + + align:start position:0% +class and you could see that in the + + + align:start position:0% +class and you could see that in the +graph here okay in Figure 13 1 you've + + align:start position:0% +graph here okay in Figure 13 1 you've + + + align:start position:0% +graph here okay in Figure 13 1 you've +got demand curve which is 3 P equals 339 + + align:start position:0% +got demand curve which is 3 P equals 339 + + + align:start position:0% +got demand curve which is 3 P equals 339 +minus Q you've got a supply curve which + + align:start position:0% +minus Q you've got a supply curve which + + + align:start position:0% +minus Q you've got a supply curve which +is a flat marginal cost at 147 you + + align:start position:0% +is a flat marginal cost at 147 you + + + align:start position:0% +is a flat marginal cost at 147 you +develop a marginal revenue function + + align:start position:0% +develop a marginal revenue function + + + align:start position:0% +develop a marginal revenue function +which is 339 minus 2q as in our previous + + align:start position:0% +which is 339 minus 2q as in our previous + + + align:start position:0% +which is 339 minus 2q as in our previous +example that's just basically an inward + + align:start position:0% +example that's just basically an inward + + + align:start position:0% +example that's just basically an inward +shift of the demand function that + + align:start position:0% +shift of the demand function that + + + align:start position:0% +shift of the demand function that +intersects marginal cost at 96 flights + + align:start position:0% +intersects marginal cost at 96 flights + + + align:start position:0% +intersects marginal cost at 96 flights +okay we have this a thousand passengers + + align:start position:0% +okay we have this a thousand passengers + + + align:start position:0% +okay we have this a thousand passengers +per quarter doesn't really matter the + + align:start position:0% +per quarter doesn't really matter the + + + align:start position:0% +per quarter doesn't really matter the +unit's ignore the you know it's just all + + align:start position:0% +unit's ignore the you know it's just all + + + align:start position:0% +unit's ignore the you know it's just all +standardization okay and then to get the + + align:start position:0% +standardization okay and then to get the + + + align:start position:0% +standardization okay and then to get the +price you read it off the demand curve + + align:start position:0% +price you read it off the demand curve + + + align:start position:0% +price you read it off the demand curve +you say ninety six flights means a price + + align:start position:0% +you say ninety six flights means a price + + + align:start position:0% +you say ninety six flights means a price +of 243 first flight okay that's what we + + align:start position:0% +of 243 first flight okay that's what we + + + align:start position:0% +of 243 first flight okay that's what we +do if American was a monopolist now + + align:start position:0% +do if American was a monopolist now + + + align:start position:0% +do if American was a monopolist now +however Americans not a monopolist + + align:start position:0% +however Americans not a monopolist + + + align:start position:0% +however Americans not a monopolist +American deals with United and American + + align:start position:0% +American deals with United and American + + + align:start position:0% +American deals with United and American +doesn't know what United's going to do + + align:start position:0% +doesn't know what United's going to do + + + align:start position:0% +doesn't know what United's going to do +so what does American do well let's say + + align:start position:0% +so what does American do well let's say + + + align:start position:0% +so what does American do well let's say +America now has to deal with the fact + + align:start position:0% +America now has to deal with the fact + + + align:start position:0% +America now has to deal with the fact +that the evening has to recognize that + + align:start position:0% +that the evening has to recognize that + + + align:start position:0% +that the evening has to recognize that +the demand it's got its own demand + + align:start position:0% +the demand it's got its own demand + + + align:start position:0% +the demand it's got its own demand +function Q a which is the total quantity + + align:start position:0% +function Q a which is the total quantity + + + align:start position:0% +function Q a which is the total quantity +in the market minus Q you okay + + align:start position:0% +in the market minus Q you okay + + + align:start position:0% +in the market minus Q you okay +so it has a residual demand function + + align:start position:0% +so it has a residual demand function + + + align:start position:0% +so it has a residual demand function +which is the total demand in the market + + align:start position:0% +which is the total demand in the market + + + align:start position:0% +which is the total demand in the market +- what United sells + + align:start position:0% +- what United sells + + + align:start position:0% +- what United sells +okay so suppose for example American + + align:start position:0% +okay so suppose for example American + + + align:start position:0% +okay so suppose for example American +thinks Americans got a spy inside United + + align:start position:0% +thinks Americans got a spy inside United + + + align:start position:0% +thinks Americans got a spy inside United +an American says ha + + align:start position:0% +an American says ha + + + align:start position:0% +an American says ha +I think United's gonna fly 64 flights ok + + align:start position:0% +I think United's gonna fly 64 flights ok + + + align:start position:0% +I think United's gonna fly 64 flights ok +so imagine America thinks United's gonna + + align:start position:0% +so imagine America thinks United's gonna + + + align:start position:0% +so imagine America thinks United's gonna +fly 64 64 flights well in that case it + + align:start position:0% +fly 64 64 flights well in that case it + + + align:start position:0% +fly 64 64 flights well in that case it +would say well in that case my arm if + + align:start position:0% +would say well in that case my arm if + + + align:start position:0% +would say well in that case my arm if +they're gonna fight 64 flights then my + + align:start position:0% +they're gonna fight 64 flights then my + + + align:start position:0% +they're gonna fight 64 flights then my +demand function is P sub a equals 339 + + align:start position:0% +demand function is P sub a equals 339 + + + align:start position:0% +demand function is P sub a equals 339 +minus Q sub a minus 64 right because the + + align:start position:0% +minus Q sub a minus 64 right because the + + + align:start position:0% +minus Q sub a minus 64 right because the +big quantity okay the big quantity is is + + align:start position:0% +big quantity okay the big quantity is is + + + align:start position:0% +big quantity okay the big quantity is is +little Q a plus little Q U so my demand + + align:start position:0% +little Q a plus little Q U so my demand + + + align:start position:0% +little Q a plus little Q U so my demand +function is 339 minus Q sub a minus 64 + + align:start position:0% +function is 339 minus Q sub a minus 64 + + + align:start position:0% +function is 339 minus Q sub a minus 64 +okay or in other words my residual + + align:start position:0% +okay or in other words my residual + + + align:start position:0% +okay or in other words my residual +demand function is that P sub a equals + + align:start position:0% +demand function is that P sub a equals + + + align:start position:0% +demand function is that P sub a equals +339 equals + + align:start position:0% +339 equals + + + align:start position:0% +339 equals +275 275 minus QA so if I think United's + + align:start position:0% +275 275 minus QA so if I think United's + + + align:start position:0% +275 275 minus QA so if I think United's +gonna fly 64 flights then my effective + + align:start position:0% +gonna fly 64 flights then my effective + + + align:start position:0% +gonna fly 64 flights then my effective +demand function is 275 minus Q and then + + align:start position:0% +demand function is 275 minus Q and then + + + align:start position:0% +demand function is 275 minus Q and then +I'm done then I just solve for what + + align:start position:0% +I'm done then I just solve for what + + + align:start position:0% +I'm done then I just solve for what +would I do as a monopolist given the + + align:start position:0% +would I do as a monopolist given the + + + align:start position:0% +would I do as a monopolist given the +other guys flying 64 flights so you can + + align:start position:0% +other guys flying 64 flights so you can + + + align:start position:0% +other guys flying 64 flights so you can +see that in Figure 13 - okay so I have a + + align:start position:0% +see that in Figure 13 - okay so I have a + + + align:start position:0% +see that in Figure 13 - okay so I have a +demand function I say well if United's + + align:start position:0% +demand function I say well if United's + + + align:start position:0% +demand function I say well if United's +gonna fly 64 flights that demand + + align:start position:0% +gonna fly 64 flights that demand + + + align:start position:0% +gonna fly 64 flights that demand +function gets shifted in by 64 and then + + align:start position:0% +function gets shifted in by 64 and then + + + align:start position:0% +function gets shifted in by 64 and then +the same thing I did before I solve for + + align:start position:0% +the same thing I did before I solve for + + + align:start position:0% +the same thing I did before I solve for +marginal revenue okay I solve for + + align:start position:0% +marginal revenue okay I solve for + + + align:start position:0% +marginal revenue okay I solve for +marginal revenue and I intersect that + + align:start position:0% +marginal revenue and I intersect that + + + align:start position:0% +marginal revenue and I intersect that +with marginal cost that's gonna happen + + align:start position:0% +with marginal cost that's gonna happen + + + align:start position:0% +with marginal cost that's gonna happen +at 64 flights and a price of 211 okay so + + align:start position:0% +at 64 flights and a price of 211 okay so + + + align:start position:0% +at 64 flights and a price of 211 okay so +basically it's the same exercise it's + + align:start position:0% +basically it's the same exercise it's + + + align:start position:0% +basically it's the same exercise it's +not that hard you just first take out + + align:start position:0% +not that hard you just first take out + + + align:start position:0% +not that hard you just first take out +what United's gonna do the problem is + + align:start position:0% +what United's gonna do the problem is + + + align:start position:0% +what United's gonna do the problem is +American doesn't have a spy they don't + + align:start position:0% +American doesn't have a spy they don't + + + align:start position:0% +American doesn't have a spy they don't +really know what United's gonna do they + + align:start position:0% +really know what United's gonna do they + + + align:start position:0% +really know what United's gonna do they +have to essentially up a strategy given + + align:start position:0% +have to essentially up a strategy given + + + align:start position:0% +have to essentially up a strategy given +the possibilities of what United might + + align:start position:0% +the possibilities of what United might + + + align:start position:0% +the possibilities of what United might +do they have to say look I don't know + + align:start position:0% +do they have to say look I don't know + + + align:start position:0% +do they have to say look I don't know +what Q sub u is so I have to devise my + + align:start position:0% +what Q sub u is so I have to devise my + + + align:start position:0% +what Q sub u is so I have to devise my +optimal strategy given Q sub u + + align:start position:0% +optimal strategy given Q sub u + + + align:start position:0% +optimal strategy given Q sub u +okay in the Lord's I have to + + align:start position:0% +okay in the Lord's I have to + + + align:start position:0% +okay in the Lord's I have to +simultaneously solve for what I would do + + align:start position:0% +simultaneously solve for what I would do + + + align:start position:0% +simultaneously solve for what I would do +at every possible quantity United would + + align:start position:0% +at every possible quantity United would + + + align:start position:0% +at every possible quantity United would +sell if to solve what I would do for + + align:start position:0% +sell if to solve what I would do for + + + align:start position:0% +sell if to solve what I would do for +every possible quantity I would sell and + + align:start position:0% +every possible quantity I would sell and + + + align:start position:0% +every possible quantity I would sell and +we call this developing your reaction or + + align:start position:0% +we call this developing your reaction or + + + align:start position:0% +we call this developing your reaction or +best response curve your reaction curve + + align:start position:0% +best response curve your reaction curve + + + align:start position:0% +best response curve your reaction curve +or your best response curve which is + + align:start position:0% +or your best response curve which is + + + align:start position:0% +or your best response curve which is +what is the best thing to do given what + + align:start position:0% +what is the best thing to do given what + + + align:start position:0% +what is the best thing to do given what +the other guy is doing what is the best + + align:start position:0% +the other guy is doing what is the best + + + align:start position:0% +the other guy is doing what is the best +thing to do given what the other guys + + align:start position:0% +thing to do given what the other guys + + + align:start position:0% +thing to do given what the other guys +doing okay you can see that in Figure 13 + + align:start position:0% +doing okay you can see that in Figure 13 + + + align:start position:0% +doing okay you can see that in Figure 13 +3 we show how that works okay + + align:start position:0% +3 we show how that works okay + + + align:start position:0% +3 we show how that works okay +that shows best response curves so for + + align:start position:0% +that shows best response curves so for + + + align:start position:0% +that shows best response curves so for +example look at the intersection on the + + align:start position:0% +example look at the intersection on the + + + align:start position:0% +example look at the intersection on the +y-axis where the red line hits the + + align:start position:0% +y-axis where the red line hits the + + + align:start position:0% +y-axis where the red line hits the +vertical hits the y-axis + + align:start position:0% +vertical hits the y-axis + + + align:start position:0% +vertical hits the y-axis +that was our monopoly equilibrium I'm + + align:start position:0% +that was our monopoly equilibrium I'm + + + align:start position:0% +that was our monopoly equilibrium I'm +sorry where the where the I'm sorry + + align:start position:0% +sorry where the where the I'm sorry + + + align:start position:0% +sorry where the where the I'm sorry +where the blue line it's the x-axis my + + align:start position:0% +where the blue line it's the x-axis my + + + align:start position:0% +where the blue line it's the x-axis my +bad we're doing American look at where + + align:start position:0% +bad we're doing American look at where + + + align:start position:0% +bad we're doing American look at where +the blue line hits the x-axis that is + + align:start position:0% +the blue line hits the x-axis that is + + + align:start position:0% +the blue line hits the x-axis that is +assuming zero united flights right where + + align:start position:0% +assuming zero united flights right where + + + align:start position:0% +assuming zero united flights right where +the blue line it's the x-axis is where + + align:start position:0% +the blue line it's the x-axis is where + + + align:start position:0% +the blue line it's the x-axis is where +the zero united flights + + align:start position:0% +the zero united flights + + + align:start position:0% +the zero united flights +well we know what american would do + + align:start position:0% +well we know what american would do + + + align:start position:0% +well we know what american would do +there they would fly 96 flights we + + align:start position:0% +there they would fly 96 flights we + + + align:start position:0% +there they would fly 96 flights we +already solve that now look at the point + + align:start position:0% +already solve that now look at the point + + + align:start position:0% +already solve that now look at the point +the point where United is flying 64 + + align:start position:0% +the point where United is flying 64 + + + align:start position:0% +the point where United is flying 64 +flights + + align:start position:0% +flights + + + align:start position:0% +flights +well we also know what American would do + + align:start position:0% +well we also know what American would do + + + align:start position:0% +well we also know what American would do +then we read off the wheat we know that + + align:start position:0% +then we read off the wheat we know that + + + align:start position:0% +then we read off the wheat we know that +we solved in the previous figure they + + align:start position:0% +we solved in the previous figure they + + + align:start position:0% +we solved in the previous figure they +would then do 64 flights and in general + + align:start position:0% +would then do 64 flights and in general + + + align:start position:0% +would then do 64 flights and in general +what that blue line is is for every + + align:start position:0% +what that blue line is is for every + + + align:start position:0% +what that blue line is is for every +quantity that United flies what does + + align:start position:0% +quantity that United flies what does + + + align:start position:0% +quantity that United flies what does +American want to fly okay now let's + + align:start position:0% +American want to fly okay now let's + + + align:start position:0% +American want to fly okay now let's +actually do and so meanwhile United is + + align:start position:0% +actually do and so meanwhile United is + + + align:start position:0% +actually do and so meanwhile United is +doing the same mathematics imagine to + + align:start position:0% +doing the same mathematics imagine to + + + align:start position:0% +doing the same mathematics imagine to +make life easy will almost always do + + align:start position:0% +make life easy will almost always do + + + align:start position:0% +make life easy will almost always do +this to make life easy + + align:start position:0% +this to make life easy + + + align:start position:0% +this to make life easy +imagine United has the same marginal + + align:start position:0% +imagine United has the same marginal + + + align:start position:0% +imagine United has the same marginal +cost American and obviously faces the + + align:start position:0% +cost American and obviously faces the + + + align:start position:0% +cost American and obviously faces the +same market demand curve + + align:start position:0% +same market demand curve + + + align:start position:0% +same market demand curve +well then literally their math is + + align:start position:0% +well then literally their math is + + + align:start position:0% +well then literally their math is +totally symmetric if American was it in + + align:start position:0% +totally symmetric if American was it in + + + align:start position:0% +totally symmetric if American was it in +the market you'd have with the red line + + align:start position:0% +the market you'd have with the red line + + + align:start position:0% +the market you'd have with the red line +intersects the vertical axis if American + + align:start position:0% +intersects the vertical axis if American + + + align:start position:0% +intersects the vertical axis if American +was flying 0 united with fly 96 light + + align:start position:0% +was flying 0 united with fly 96 light + + + align:start position:0% +was flying 0 united with fly 96 light +because their problem is identical to + + align:start position:0% +because their problem is identical to + + + align:start position:0% +because their problem is identical to +Americans monopoly problem likewise so + + align:start position:0% +Americans monopoly problem likewise so + + + align:start position:0% +Americans monopoly problem likewise so +that red the red line is united best + + align:start position:0% +that red the red line is united best + + + align:start position:0% +that red the red line is united best +response curve so we've graphed for + + align:start position:0% +response curve so we've graphed for + + + align:start position:0% +response curve so we've graphed for +every possible amount of flights that + + align:start position:0% +every possible amount of flights that + + + align:start position:0% +every possible amount of flights that +United does what's Americans optimal + + align:start position:0% +United does what's Americans optimal + + + align:start position:0% +United does what's Americans optimal +amount of flights we've solved for every + + align:start position:0% +amount of flights we've solved for every + + + align:start position:0% +amount of flights we've solved for every +amount of flights that American does + + align:start position:0% +amount of flights that American does + + + align:start position:0% +amount of flights that American does +which United off the amount of flights + + align:start position:0% +which United off the amount of flights + + + align:start position:0% +which United off the amount of flights +where those lines intersect is the + + align:start position:0% +where those lines intersect is the + + + align:start position:0% +where those lines intersect is the +cournot equilibrium why is that the + + align:start position:0% +cournot equilibrium why is that the + + + align:start position:0% +cournot equilibrium why is that the +konoka Librium because at that point + + align:start position:0% +konoka Librium because at that point + + + align:start position:0% +konoka Librium because at that point +both firms are doing the best they can + + align:start position:0% +both firms are doing the best they can + + + align:start position:0% +both firms are doing the best they can +give them what the other firms chosen in + + align:start position:0% +give them what the other firms chosen in + + + align:start position:0% +give them what the other firms chosen in +other words to say this is given what + + align:start position:0% +other words to say this is given what + + + align:start position:0% +other words to say this is given what +the other firms doing neither firm wants + + align:start position:0% +the other firms doing neither firm wants + + + align:start position:0% +the other firms doing neither firm wants +to deviate the profit maximizing choice + + align:start position:0% +to deviate the profit maximizing choice + + + align:start position:0% +to deviate the profit maximizing choice +is to be where they are given the other + + align:start position:0% +is to be where they are given the other + + + align:start position:0% +is to be where they are given the other +firms behavior okay so basically the + + align:start position:0% +firms behavior okay so basically the + + + align:start position:0% +firms behavior okay so basically the +cournot equilibrium is the only + + align:start position:0% +cournot equilibrium is the only + + + align:start position:0% +cournot equilibrium is the only +equilibrium that's possible + + align:start position:0% +equilibrium that's possible + + + align:start position:0% +equilibrium that's possible +in this market okay so and why is that + + align:start position:0% +in this market okay so and why is that + + + align:start position:0% +in this market okay so and why is that +so for example imagine that American + + align:start position:0% +so for example imagine that American + + + align:start position:0% +so for example imagine that American +came in and said look I like doing 96 + + align:start position:0% +came in and said look I like doing 96 + + + align:start position:0% +came in and said look I like doing 96 +flights + + align:start position:0% +flights + + + align:start position:0% +flights +I love being monopolist I'm just dude 96 + + align:start position:0% +I love being monopolist I'm just dude 96 + + + align:start position:0% +I love being monopolist I'm just dude 96 +flights and I'm gonna charge vomited + + align:start position:0% +flights and I'm gonna charge vomited + + + align:start position:0% +flights and I'm gonna charge vomited +nine six flights I'm in charge of $43 + + align:start position:0% +nine six flights I'm in charge of $43 + + + align:start position:0% +nine six flights I'm in charge of $43 +well in that case American United I'm + + align:start position:0% +well in that case American United I'm + + + align:start position:0% +well in that case American United I'm +sorry would happily come in at two + + align:start position:0% +sorry would happily come in at two + + + align:start position:0% +sorry would happily come in at two +hundred and forty two dollars and + + align:start position:0% +hundred and forty two dollars and + + + align:start position:0% +hundred and forty two dollars and +undercut them and sell lots of flights + + align:start position:0% +undercut them and sell lots of flights + + + align:start position:0% +undercut them and sell lots of flights +because that's still well above marginal + + align:start position:0% +because that's still well above marginal + + + align:start position:0% +because that's still well above marginal +cost so that's not an equilibrium + + align:start position:0% +cost so that's not an equilibrium + + + align:start position:0% +cost so that's not an equilibrium +because because United and American are + + align:start position:0% +because because United and American are + + + align:start position:0% +because because United and American are +choosing different outcomes it's only I + + align:start position:0% +choosing different outcomes it's only I + + + align:start position:0% +choosing different outcomes it's only I +could have they both it's they're both + + align:start position:0% +could have they both it's they're both + + + align:start position:0% +could have they both it's they're both +to the point where the same outcome + + align:start position:0% +to the point where the same outcome + + + align:start position:0% +to the point where the same outcome +makes them both happy okay so that's the + + align:start position:0% +makes them both happy okay so that's the + + + align:start position:0% +makes them both happy okay so that's the +graphics let's actually do the let's do + + align:start position:0% +graphics let's actually do the let's do + + + align:start position:0% +graphics let's actually do the let's do +the math here let's do the cournot math + + align:start position:0% + + + + align:start position:0% + +okay in general the residual demand for + + align:start position:0% +okay in general the residual demand for + + + align:start position:0% +okay in general the residual demand for +American is that P equals 339 minus Q a + + align:start position:0% +American is that P equals 339 minus Q a + + + align:start position:0% +American is that P equals 339 minus Q a +minus Q you okay remember big Q is Q a + + align:start position:0% +minus Q you okay remember big Q is Q a + + + align:start position:0% +minus Q you okay remember big Q is Q a +plus Q you so since big Q since the + + align:start position:0% +plus Q you so since big Q since the + + + align:start position:0% +plus Q you so since big Q since the +demand function is 339 minus big Q I + + align:start position:0% +demand function is 339 minus big Q I + + + align:start position:0% +demand function is 339 minus big Q I +simply broke big Q into Q a and Q you + + align:start position:0% +simply broke big Q into Q a and Q you + + + align:start position:0% +simply broke big Q into Q a and Q you +okay it's not meat this all unclear + + align:start position:0% +okay it's not meat this all unclear + + + align:start position:0% +okay it's not meat this all unclear +simply broke up the big Q into those two + + align:start position:0% +simply broke up the big Q into those two + + + align:start position:0% +simply broke up the big Q into those two +components so that means that Americans + + align:start position:0% +components so that means that Americans + + + align:start position:0% +components so that means that Americans +revenue function that's called revenue a + + align:start position:0% +revenue function that's called revenue a + + + align:start position:0% +revenue function that's called revenue a +revenue for American is 339 times Q a + + align:start position:0% +revenue for American is 339 times Q a + + + align:start position:0% +revenue for American is 339 times Q a +minus Q a squared minus Q aqu this is a + + align:start position:0% +minus Q a squared minus Q aqu this is a + + + align:start position:0% +minus Q a squared minus Q aqu this is a +new term this was the old this was the + + align:start position:0% +new term this was the old this was the + + + align:start position:0% +new term this was the old this was the +old revenue function we had when they + + align:start position:0% +old revenue function we had when they + + + align:start position:0% +old revenue function we had when they +were innopolis now I've got this new + + align:start position:0% +were innopolis now I've got this new + + + align:start position:0% +were innopolis now I've got this new +term that didn't exist before + + align:start position:0% +term that didn't exist before + + + align:start position:0% +term that didn't exist before +so that means their marginal revenue for + + align:start position:0% +so that means their marginal revenue for + + + align:start position:0% +so that means their marginal revenue for +American is now 339 minus 2q a minus Q U + + align:start position:0% +American is now 339 minus 2q a minus Q U + + + align:start position:0% +American is now 339 minus 2q a minus Q U +so now their marginal revenue is + + align:start position:0% +so now their marginal revenue is + + + align:start position:0% +so now their marginal revenue is +actually a function of their own + + align:start position:0% +actually a function of their own + + + align:start position:0% +actually a function of their own +behavior but their competitors behavior + + align:start position:0% +behavior but their competitors behavior + + + align:start position:0% +behavior but their competitors behavior +that's the new marginal revenue function + + align:start position:0% +that's the new marginal revenue function + + + align:start position:0% +that's the new marginal revenue function +okay now but the profit maximization + + align:start position:0% +okay now but the profit maximization + + + align:start position:0% +okay now but the profit maximization +rules the same you just set that equal + + align:start position:0% +rules the same you just set that equal + + + align:start position:0% +rules the same you just set that equal +to marginal cost + + align:start position:0% +to marginal cost + + + align:start position:0% +to marginal cost +she said equal to 147 and you solve and + + align:start position:0% +she said equal to 147 and you solve and + + + align:start position:0% +she said equal to 147 and you solve and +what you end up getting is the Q sub a + + align:start position:0% +what you end up getting is the Q sub a + + + align:start position:0% +what you end up getting is the Q sub a +star the outcome Q sub a is 96 minus + + align:start position:0% +star the outcome Q sub a is 96 minus + + + align:start position:0% +star the outcome Q sub a is 96 minus +one-half Q U star or qu q a star is 96 + + align:start position:0% +one-half Q U star or qu q a star is 96 + + + align:start position:0% +one-half Q U star or qu q a star is 96 +minus one-half qu if you solve this + + align:start position:0% +minus one-half qu if you solve this + + + align:start position:0% +minus one-half qu if you solve this +equation that's what you get that's + + align:start position:0% +equation that's what you get that's + + + align:start position:0% +equation that's what you get that's +one-half one-half qu so now we have the + + align:start position:0% +one-half one-half qu so now we have the + + + align:start position:0% +one-half one-half qu so now we have the +optimal quantity but it's a function + + align:start position:0% +optimal quantity but it's a function + + + align:start position:0% +optimal quantity but it's a function +what the other guy does that's a problem + + align:start position:0% +what the other guy does that's a problem + + + align:start position:0% +what the other guy does that's a problem +except that we use the same math for + + align:start position:0% +except that we use the same math for + + + align:start position:0% +except that we use the same math for +United now if the problem symmetric you + + align:start position:0% +United now if the problem symmetric you + + + align:start position:0% +United now if the problem symmetric you +don't have to do the math again you know + + align:start position:0% +don't have to do the math again you know + + + align:start position:0% +don't have to do the math again you know +the best response function will be + + align:start position:0% +the best response function will be + + + align:start position:0% +the best response function will be +symmetric but that won't always be the + + align:start position:0% +symmetric but that won't always be the + + + align:start position:0% +symmetric but that won't always be the +case so I'm gonna do a shortcut here of + + align:start position:0% +case so I'm gonna do a shortcut here of + + + align:start position:0% +case so I'm gonna do a shortcut here of +saying the best response function for Q + + align:start position:0% +saying the best response function for Q + + + align:start position:0% +saying the best response function for Q +you + + align:start position:0% +you + + + align:start position:0% +you +is Q star u equals 96 minus 1/2 QA okay + + align:start position:0% +is Q star u equals 96 minus 1/2 QA okay + + + align:start position:0% +is Q star u equals 96 minus 1/2 QA okay +so I've just written down their best + + align:start position:0% +so I've just written down their best + + + align:start position:0% +so I've just written down their best +response functions correspond to the + + align:start position:0% +response functions correspond to the + + + align:start position:0% +response functions correspond to the +graph look at the so Q star a that's the + + align:start position:0% +graph look at the so Q star a that's the + + + align:start position:0% +graph look at the so Q star a that's the +blue line it's 96 minus one-half Q you + + align:start position:0% +blue line it's 96 minus one-half Q you + + + align:start position:0% +blue line it's 96 minus one-half Q you +okay + + align:start position:0% +okay + + + align:start position:0% +okay +choose star u that's a red line 96 minus + + align:start position:0% +choose star u that's a red line 96 minus + + + align:start position:0% +choose star u that's a red line 96 minus +1/2 QA that's the best france function + + align:start position:0% +1/2 QA that's the best france function + + + align:start position:0% +1/2 QA that's the best france function +now once again to remind you i could + + align:start position:0% +now once again to remind you i could + + + align:start position:0% +now once again to remind you i could +simply skip to this step but normally + + align:start position:0% +simply skip to this step but normally + + + align:start position:0% +simply skip to this step but normally +you have to solve through for both firms + + align:start position:0% +you have to solve through for both firms + + + align:start position:0% +you have to solve through for both firms +they might not have identical best + + align:start position:0% +they might not have identical best + + + align:start position:0% +they might not have identical best +response functions or symmetrical best + + align:start position:0% +response functions or symmetrical best + + + align:start position:0% +response functions or symmetrical best +response function well now we're golden + + align:start position:0% +response function well now we're golden + + + align:start position:0% +response function well now we're golden +we have two equations and two unknowns + + align:start position:0% +we have two equations and two unknowns + + + align:start position:0% +we have two equations and two unknowns +we know how to deal with that and you + + align:start position:0% +we know how to deal with that and you + + + align:start position:0% +we know how to deal with that and you +solve them and you get the Q a star + + align:start position:0% +solve them and you get the Q a star + + + align:start position:0% +solve them and you get the Q a star +equals Q u star equals 64 you solve + + align:start position:0% +equals Q u star equals 64 you solve + + + align:start position:0% +equals Q u star equals 64 you solve +those two equations two unknowns okay so + + align:start position:0% +those two equations two unknowns okay so + + + align:start position:0% +those two equations two unknowns okay so +64 it's a solution to that system what's + + align:start position:0% +64 it's a solution to that system what's + + + align:start position:0% +64 it's a solution to that system what's +the price + + align:start position:0% +the price + + + align:start position:0% +the price +so in raise their hand and tell me + + align:start position:0% +so in raise their hand and tell me + + + align:start position:0% +so in raise their hand and tell me +what's the price without looking at the + + align:start position:0% +what's the price without looking at the + + + align:start position:0% +what's the price without looking at the +graph yeah and how did you get that you + + align:start position:0% +graph yeah and how did you get that you + + + align:start position:0% +graph yeah and how did you get that you +gotta plug in 64 twice a lot of you'll + + align:start position:0% +gotta plug in 64 twice a lot of you'll + + + align:start position:0% +gotta plug in 64 twice a lot of you'll +get this wrong you'll say Oh 339 minus + + align:start position:0% +get this wrong you'll say Oh 339 minus + + + align:start position:0% +get this wrong you'll say Oh 339 minus +64 but no its 339 minus 128 because + + align:start position:0% +64 but no its 339 minus 128 because + + + align:start position:0% +64 but no its 339 minus 128 because +they're each flying 64 and the price + + align:start position:0% +they're each flying 64 and the price + + + align:start position:0% +they're each flying 64 and the price +comes from the total demand in the + + align:start position:0% +comes from the total demand in the + + + align:start position:0% +comes from the total demand in the +market so the price is 211 okay that's + + align:start position:0% +market so the price is 211 okay that's + + + align:start position:0% +market so the price is 211 okay that's +an important mistake to avoid a lot of + + align:start position:0% +an important mistake to avoid a lot of + + + align:start position:0% +an important mistake to avoid a lot of +people get here they'll be super excited + + align:start position:0% +people get here they'll be super excited + + + align:start position:0% +people get here they'll be super excited +they're tired they throw the 64 back of + + align:start position:0% +they're tired they throw the 64 back of + + + align:start position:0% +they're tired they throw the 64 back of +the main equation but remember demands a + + align:start position:0% +the main equation but remember demands a + + + align:start position:0% +the main equation but remember demands a +function of the total market if Symetra + + align:start position:0% +function of the total market if Symetra + + + align:start position:0% +function of the total market if Symetra +gluts doing 64 then the price is gonna + + align:start position:0% +gluts doing 64 then the price is gonna + + + align:start position:0% +gluts doing 64 then the price is gonna +be 211 and that is the Nash or cournot + + align:start position:0% +be 211 and that is the Nash or cournot + + + align:start position:0% +be 211 and that is the Nash or cournot +equilibrium both firms are happy to fly + + align:start position:0% +equilibrium both firms are happy to fly + + + align:start position:0% +equilibrium both firms are happy to fly +64 flights at a price of 2 11 neither + + align:start position:0% +64 flights at a price of 2 11 neither + + + align:start position:0% +64 flights at a price of 2 11 neither +firm wants to deviate and you know that + + align:start position:0% +firm wants to deviate and you know that + + + align:start position:0% +firm wants to deviate and you know that +because you've maximized their profits + + align:start position:0% +because you've maximized their profits + + + align:start position:0% +because you've maximized their profits +and the profits for American are + + align:start position:0% +and the profits for American are + + + align:start position:0% +and the profits for American are +maximized when United's lying 64 the + + align:start position:0% +maximized when United's lying 64 the + + + align:start position:0% +maximized when United's lying 64 the +profits to American are maximized at + + align:start position:0% +profits to American are maximized at + + + align:start position:0% +profits to American are maximized at +flying 64 when Americans flying 64 the + + align:start position:0% +flying 64 when Americans flying 64 the + + + align:start position:0% +flying 64 when Americans flying 64 the +profits for United are maximized at + + align:start position:0% +profits for United are maximized at + + + align:start position:0% +profits for United are maximized at +flying 64 therefore that is the national + + align:start position:0% +flying 64 therefore that is the national + + + align:start position:0% +flying 64 therefore that is the national +equilibrium okay now when we get to + + align:start position:0% +equilibrium okay now when we get to + + + align:start position:0% +equilibrium okay now when we get to +reality things might not always work out + + align:start position:0% +reality things might not always work out + + + align:start position:0% +reality things might not always work out +so neatly things might not be symmetric + + align:start position:0% +so neatly things might not be symmetric + + + align:start position:0% +so neatly things might not be symmetric +you might also not have an equilibrium + + align:start position:0% +you might also not have an equilibrium + + + align:start position:0% +you might also not have an equilibrium +how could you not have an equilibrium + + align:start position:0% +how could you not have an equilibrium + + + align:start position:0% +how could you not have an equilibrium +here how could that happen + + align:start position:0% +here how could that happen + + + align:start position:0% +here how could that happen +graphically what would that mean yeah + + align:start position:0% +graphically what would that mean yeah + + + align:start position:0% +graphically what would that mean yeah +yeah the best response occurs might not + + align:start position:0% +yeah the best response occurs might not + + + align:start position:0% +yeah the best response occurs might not +intersect you might not get an + + align:start position:0% +intersect you might not get an + + + align:start position:0% +intersect you might not get an +equilibrium we don't know what the hell + + align:start position:0% +equilibrium we don't know what the hell + + + align:start position:0% +equilibrium we don't know what the hell +to do then all chaos breaks loose okay + + align:start position:0% +to do then all chaos breaks loose okay + + + align:start position:0% +to do then all chaos breaks loose okay +but you might not get a knuckle Librium + + align:start position:0% +but you might not get a knuckle Librium + + + align:start position:0% +but you might not get a knuckle Librium +okay in this market because the best + + align:start position:0% +okay in this market because the best + + + align:start position:0% +okay in this market because the best +response curves might uh might not + + align:start position:0% +response curves might uh might not + + + align:start position:0% +response curves might uh might not +intersect okay + + align:start position:0% +intersect okay + + + align:start position:0% +intersect okay +in reality in life you could have funky + + align:start position:0% +in reality in life you could have funky + + + align:start position:0% +in reality in life you could have funky +best response curves that are nonlinear + + align:start position:0% +best response curves that are nonlinear + + + align:start position:0% +best response curves that are nonlinear +you can have multiple intersections you + + align:start position:0% +you can have multiple intersections you + + + align:start position:0% +you can have multiple intersections you +could have multiple we call multiple + + align:start position:0% +could have multiple we call multiple + + + align:start position:0% +could have multiple we call multiple +equilibria and then it becomes an + + align:start position:0% +equilibria and then it becomes an + + + align:start position:0% +equilibria and then it becomes an +indeterminant problem and you have to + + align:start position:0% +indeterminant problem and you have to + + + align:start position:0% +indeterminant problem and you have to +figure out which equlibrium they settle + + align:start position:0% +figure out which equlibrium they settle + + + align:start position:0% +figure out which equlibrium they settle +at and that involves higher-order + + align:start position:0% +at and that involves higher-order + + + align:start position:0% +at and that involves higher-order +mathematics that you talked about in + + align:start position:0% +mathematics that you talked about in + + + align:start position:0% +mathematics that you talked about in +more advanced classes so this is sort of + + align:start position:0% +more advanced classes so this is sort of + + + align:start position:0% +more advanced classes so this is sort of +the simplest easiest cases symmetric + + align:start position:0% +the simplest easiest cases symmetric + + + align:start position:0% +the simplest easiest cases symmetric +case with linear best response functions + + align:start position:0% +case with linear best response functions + + + align:start position:0% +case with linear best response functions +intersect is your easiest case but in + + align:start position:0% +intersect is your easiest case but in + + + align:start position:0% +intersect is your easiest case but in +general the general way to solve this is + + align:start position:0% +general the general way to solve this is + + + align:start position:0% +general the general way to solve this is +the same which is to look is to use the + + align:start position:0% +the same which is to look is to use the + + + align:start position:0% +the same which is to look is to use the +principle of game theory look go back to + + align:start position:0% +principle of game theory look go back to + + + align:start position:0% +principle of game theory look go back to +the prisoner's dilemma okay all we're + + align:start position:0% +the prisoner's dilemma okay all we're + + + align:start position:0% +the prisoner's dilemma okay all we're +doing here was creating best response + + align:start position:0% +doing here was creating best response + + + align:start position:0% +doing here was creating best response +functions it's just there wasn't a line + + align:start position:0% +functions it's just there wasn't a line + + + align:start position:0% +functions it's just there wasn't a line +it was just a point the best response + + align:start position:0% +it was just a point the best response + + + align:start position:0% +it was just a point the best response +function was what we laid out here all + + align:start position:0% +function was what we laid out here all + + + align:start position:0% +function was what we laid out here all +we do is see United American examples go + + align:start position:0% +we do is see United American examples go + + + align:start position:0% +we do is see United American examples go +to a continuum and about best response + + align:start position:0% +to a continuum and about best response + + + align:start position:0% +to a continuum and about best response +functions is the best response point + + align:start position:0% +functions is the best response point + + + align:start position:0% +functions is the best response point +okay yeah + + align:start position:0% + + + + align:start position:0% + +other questions okay let's stop there + + align:start position:0% +other questions okay let's stop there + + + align:start position:0% +other questions okay let's stop there +we'll come back next time we'll talk + + align:start position:0% +we'll come back next time we'll talk + + + align:start position:0% +we'll come back next time we'll talk +about why don't we why don't we all just + + align:start position:0% +about why don't we why don't we all just + + + align:start position:0% +about why don't we why don't we all just +get along like mr. Rogers wants \ No newline at end of file diff --git a/0x4Jf6hBr-k.txt b/0x4Jf6hBr-k.txt new file mode 100644 index 0000000000000000000000000000000000000000..394a8a08b1b58c37c6ae1eb8c2a2b7a845d97072 --- /dev/null +++ b/0x4Jf6hBr-k.txt @@ -0,0 +1,16699 @@ +align:start position:0% + +The following content is provided under + + align:start position:0% +The following content is provided under + + + align:start position:0% +The following content is provided under +a creative common license. Your support + + align:start position:0% +a creative common license. Your support + + + align:start position:0% +a creative common license. Your support +will help MIT Open Courseware continue + + align:start position:0% +will help MIT Open Courseware continue + + + align:start position:0% +will help MIT Open Courseware continue +to offer high-quality educational + + align:start position:0% +to offer high-quality educational + + + align:start position:0% +to offer high-quality educational +resources for free. To make a donation + + align:start position:0% +resources for free. To make a donation + + + align:start position:0% +resources for free. To make a donation +or view additional materials from + + align:start position:0% +or view additional materials from + + + align:start position:0% +or view additional materials from +hundreds of MIT courses, visit MIT Open + + align:start position:0% +hundreds of MIT courses, visit MIT Open + + + align:start position:0% +hundreds of MIT courses, visit MIT Open +Courseware at ocw.mmit.edu. + + align:start position:0% +Courseware at ocw.mmit.edu. + + + align:start position:0% +Courseware at ocw.mmit.edu. +>> Before we move on to the rest of the + + align:start position:0% +>> Before we move on to the rest of the + + + align:start position:0% +>> Before we move on to the rest of the +topics, uh maybe just a some + + align:start position:0% +topics, uh maybe just a some + + + align:start position:0% +topics, uh maybe just a some +administrative stuff about the next + + align:start position:0% +administrative stuff about the next + + + align:start position:0% +administrative stuff about the next +assignment. Uh so the idea is to model a + + align:start position:0% +assignment. Uh so the idea is to model a + + + align:start position:0% +assignment. Uh so the idea is to model a +system right? Uh so the idea is to pick + + align:start position:0% +system right? Uh so the idea is to pick + + + align:start position:0% +system right? Uh so the idea is to pick +some sort of the old system. Um + + align:start position:0% +some sort of the old system. Um + + + align:start position:0% +some sort of the old system. Um +in the past people have picked stuff + + align:start position:0% +in the past people have picked stuff + + + align:start position:0% +in the past people have picked stuff +like applying for college because they + + align:start position:0% +like applying for college because they + + + align:start position:0% +like applying for college because they +knew all about that. Uh they you know + + align:start position:0% +knew all about that. Uh they you know + + + align:start position:0% +knew all about that. Uh they you know +people have talked about uh an example I + + align:start position:0% +people have talked about uh an example I + + + align:start position:0% +people have talked about uh an example I +give is you know running a nuclear + + align:start position:0% +give is you know running a nuclear + + + align:start position:0% +give is you know running a nuclear +reactor or something. That's basically + + align:start position:0% +reactor or something. That's basically + + + align:start position:0% +reactor or something. That's basically +there's a there's a uh but hey, you + + align:start position:0% +there's a there's a uh but hey, you + + + align:start position:0% +there's a there's a uh but hey, you +know, if if any of you are new to + + align:start position:0% +know, if if any of you are new to + + + align:start position:0% +know, if if any of you are new to +science majors, you know, + + align:start position:0% +science majors, you know, + + + align:start position:0% +science majors, you know, +>> Oh, perfect. Okay. All right. Well, one + + align:start position:0% +>> Oh, perfect. Okay. All right. Well, one + + + align:start position:0% +>> Oh, perfect. Okay. All right. Well, one +of one of my favorite 2 games was was + + align:start position:0% +of one of my favorite 2 games was was + + + align:start position:0% +of one of my favorite 2 games was was +actually uh nuclear reactor simulation. + + align:start position:0% +actually uh nuclear reactor simulation. + + + align:start position:0% +actually uh nuclear reactor simulation. +It always melted down. That's why it was + + align:start position:0% +It always melted down. That's why it was + + + align:start position:0% +It always melted down. That's why it was +fun. Awesome. Um but yeah, you know, + + align:start position:0% +fun. Awesome. Um but yeah, you know, + + + align:start position:0% +fun. Awesome. Um but yeah, you know, +pick pick a real world system to model + + align:start position:0% +pick pick a real world system to model + + + align:start position:0% +pick pick a real world system to model +um to start uh modeling. Obviously, + + align:start position:0% +um to start uh modeling. Obviously, + + + align:start position:0% +um to start uh modeling. Obviously, +you're trying to find a fun. Obviously, + + align:start position:0% +you're trying to find a fun. Obviously, + + + align:start position:0% +you're trying to find a fun. Obviously, +you're trying to make something that + + align:start position:0% +you're trying to make something that + + + align:start position:0% +you're trying to make something that +people are going to enjoy playing. Uh uh + + align:start position:0% +people are going to enjoy playing. Uh uh + + + align:start position:0% +people are going to enjoy playing. Uh uh +but the the idea is to start from a + + align:start position:0% +but the the idea is to start from a + + + align:start position:0% +but the the idea is to start from a +slightly different place from where we + + align:start position:0% +slightly different place from where we + + + align:start position:0% +slightly different place from where we +had uh uh um in the first assignment. + + align:start position:0% +had uh uh um in the first assignment. + + + align:start position:0% +had uh uh um in the first assignment. +Now, a couple of you guys already did + + align:start position:0% +Now, a couple of you guys already did + + + align:start position:0% +Now, a couple of you guys already did +that for the first assignment though. I + + align:start position:0% +that for the first assignment though. I + + + align:start position:0% +that for the first assignment though. I +mean, things like picking up girls at a + + align:start position:0% +mean, things like picking up girls at a + + + align:start position:0% +mean, things like picking up girls at a +party. I mean, you're modeling real + + align:start position:0% +party. I mean, you're modeling real + + + align:start position:0% +party. I mean, you're modeling real +system in a sense. Uh still haven't + + align:start position:0% +system in a sense. Uh still haven't + + + align:start position:0% +system in a sense. Uh still haven't +played the genealogy game yet. So So, so + + align:start position:0% +played the genealogy game yet. So So, so + + + align:start position:0% +played the genealogy game yet. So So, so +we're going to play that tomorrow. So, + + align:start position:0% +we're going to play that tomorrow. So, + + + align:start position:0% +we're going to play that tomorrow. So, +so + + align:start position:0% +so + + + align:start position:0% +so +we'll see that. Um the the survival + + align:start position:0% +we'll see that. Um the the survival + + + align:start position:0% +we'll see that. Um the the survival +horror game I would say is not a real + + align:start position:0% +horror game I would say is not a real + + + align:start position:0% +horror game I would say is not a real +world system. + + align:start position:0% +world system. + + + align:start position:0% +world system. +>> It was a system. + + align:start position:0% +>> It was a system. + + + align:start position:0% +>> It was a system. +>> Tasers. + + align:start position:0% +>> Tasers. + + + align:start position:0% +>> Tasers. +>> Yeah. Or wizards enemies. + + align:start position:0% +>> Yeah. Or wizards enemies. + + + align:start position:0% +>> Yeah. Or wizards enemies. +>> But uh so so yeah, pick pick something. + + align:start position:0% +>> But uh so so yeah, pick pick something. + + + align:start position:0% +>> But uh so so yeah, pick pick something. +Um uh we've seen games um uh negotiating + + align:start position:0% +Um uh we've seen games um uh negotiating + + + align:start position:0% +Um uh we've seen games um uh negotiating +around like negotiating uh greenhouse + + align:start position:0% +around like negotiating uh greenhouse + + + align:start position:0% +around like negotiating uh greenhouse +gas emissions. There was there was one + + align:start position:0% +gas emissions. There was there was one + + + align:start position:0% +gas emissions. There was there was one +uh which was really really cutthroat as + + align:start position:0% +uh which was really really cutthroat as + + + align:start position:0% +uh which was really really cutthroat as +you'll probably imagine. + + align:start position:0% +you'll probably imagine. + + + align:start position:0% +you'll probably imagine. +>> Yeah. + + align:start position:0% +>> Yeah. + + + align:start position:0% +>> Yeah. +>> Um actually I'll try to I'll try to get + + align:start position:0% +>> Um actually I'll try to I'll try to get + + + align:start position:0% +>> Um actually I'll try to I'll try to get +the team to come in late in the semester + + align:start position:0% +the team to come in late in the semester + + + align:start position:0% +the team to come in late in the semester +to talk about the card game. Uh this was + + align:start position:0% +to talk about the card game. Uh this was + + + align:start position:0% +to talk about the card game. Uh this was +a freshman team on Periscope. + + align:start position:0% +a freshman team on Periscope. + + + align:start position:0% +a freshman team on Periscope. +Um let's see. Uh you on Wednesday we're + + align:start position:0% +Um let's see. Uh you on Wednesday we're + + + align:start position:0% +Um let's see. Uh you on Wednesday we're +going to do the usual brainstorming + + align:start position:0% +going to do the usual brainstorming + + + align:start position:0% +going to do the usual brainstorming +exercise in the second half of the of + + align:start position:0% +exercise in the second half of the of + + + align:start position:0% +exercise in the second half of the of +the class. You know everybody throw out + + align:start position:0% +the class. You know everybody throw out + + + align:start position:0% +the class. You know everybody throw out +your ideas come in with a bunch of + + align:start position:0% +your ideas come in with a bunch of + + + align:start position:0% +your ideas come in with a bunch of +ideas. We'll try to build on that. Um + + align:start position:0% +ideas. We'll try to build on that. Um + + + align:start position:0% +ideas. We'll try to build on that. Um +but uh this time around you're allowed + + align:start position:0% +but uh this time around you're allowed + + + align:start position:0% +but uh this time around you're allowed +to actually pre-build your team. You + + align:start position:0% +to actually pre-build your team. You + + + align:start position:0% +to actually pre-build your team. You +you're allowed to to to ask people, you + + align:start position:0% +you're allowed to to to ask people, you + + + align:start position:0% +you're allowed to to to ask people, you +know, hey, you guys want to work + + align:start position:0% +know, hey, you guys want to work + + + align:start position:0% +know, hey, you guys want to work +together? Um you don't actually have to + + align:start position:0% +together? Um you don't actually have to + + + align:start position:0% +together? Um you don't actually have to +like figure it out on the spot if you + + align:start position:0% +like figure it out on the spot if you + + + align:start position:0% +like figure it out on the spot if you +don't want to. Um I don't really care + + align:start position:0% +don't want to. Um I don't really care + + + align:start position:0% +don't want to. Um I don't really care +how you do it as long as by Friday you + + align:start position:0% +how you do it as long as by Friday you + + + align:start position:0% +how you do it as long as by Friday you +know who your team is. Um and and who's + + align:start position:0% +know who your team is. Um and and who's + + + align:start position:0% +know who your team is. Um and and who's +on team sizes are are the same. + + align:start position:0% +on team sizes are are the same. + + + align:start position:0% +on team sizes are are the same. +So + + align:start position:0% +So + + + align:start position:0% +So +any questions? Are we able to simulate + + align:start position:0% +any questions? Are we able to simulate + + + align:start position:0% +any questions? Are we able to simulate +things that aren't from like this era? + + align:start position:0% +things that aren't from like this era? + + + align:start position:0% +things that aren't from like this era? +>> Yeah. + + align:start position:0% +>> Yeah. + + + align:start position:0% +>> Yeah. +>> Okay. + + align:start position:0% +>> Okay. + + + align:start position:0% +>> Okay. +>> Like like from history? + + align:start position:0% +>> Like like from history? + + + align:start position:0% +>> Like like from history? +>> Yeah. + + align:start position:0% +>> Yeah. + + + align:start position:0% +>> Yeah. +>> Okay. Not from like the future. + + align:start position:0% +>> Okay. Not from like the future. + + + align:start position:0% +>> Okay. Not from like the future. +>> Oh, + + align:start position:0% +>> Oh, + + + align:start position:0% +>> Oh, +>> no. + + align:start position:0% + + + + align:start position:0% + +Future. + + align:start position:0% +Future. + + + align:start position:0% +Future. +>> Yeah. Yeah. Sure. It's like this is how + + align:start position:0% +>> Yeah. Yeah. Sure. It's like this is how + + + align:start position:0% +>> Yeah. Yeah. Sure. It's like this is how +things are going to work. + + align:start position:0% +things are going to work. + + + align:start position:0% +things are going to work. +>> Well, well, I mean I mean Okay. So, so + + align:start position:0% +>> Well, well, I mean I mean Okay. So, so + + + align:start position:0% +>> Well, well, I mean I mean Okay. So, so +yes. Yes. Absolutely. Historical stuff. + + align:start position:0% +yes. Yes. Absolutely. Historical stuff. + + + align:start position:0% +yes. Yes. Absolutely. Historical stuff. +Uh um and but you do have some + + align:start position:0% +Uh um and but you do have some + + + align:start position:0% +Uh um and but you do have some +liberties. Uh I'm not saying that your + + align:start position:0% +liberties. Uh I'm not saying that your + + + align:start position:0% +liberties. Uh I'm not saying that your +game has to be a faithful simulation. Am + + align:start position:0% +game has to be a faithful simulation. Am + + + align:start position:0% +game has to be a faithful simulation. Am +I getting a little bit more into + + align:start position:0% +I getting a little bit more into + + + align:start position:0% +I getting a little bit more into +simulation? say um but it doesn't have + + align:start position:0% +simulation? say um but it doesn't have + + + align:start position:0% +simulation? say um but it doesn't have +to be a faithful simulation necessarily + + align:start position:0% +to be a faithful simulation necessarily + + + align:start position:0% +to be a faithful simulation necessarily +of what you're talking but you know in a + + align:start position:0% +of what you're talking but you know in a + + + align:start position:0% +of what you're talking but you know in a +sense you're trying to like capture the + + align:start position:0% +sense you're trying to like capture the + + + align:start position:0% +sense you're trying to like capture the +spirit of it um you know if if if the + + align:start position:0% +spirit of it um you know if if if the + + + align:start position:0% +spirit of it um you know if if if the +point is I'm running a nuclear reactor + + align:start position:0% +point is I'm running a nuclear reactor + + + align:start position:0% +point is I'm running a nuclear reactor +and you can sort of capture the oh my + + align:start position:0% +and you can sort of capture the oh my + + + align:start position:0% +and you can sort of capture the oh my +god it's so dangerous or the oh my god + + align:start position:0% +god it's so dangerous or the oh my god + + + align:start position:0% +god it's so dangerous or the oh my god +it's so boring aspect of it uh have you + + align:start position:0% +it's so boring aspect of it uh have you + + + align:start position:0% +it's so boring aspect of it uh have you +actually worked on nuclear reactor + + align:start position:0% +actually worked on nuclear reactor + + + align:start position:0% +actually worked on nuclear reactor +>> well there + + align:start position:0% +>> well there + + + align:start position:0% +>> well there +>> and I know like the mechanics of it but + + align:start position:0% +>> and I know like the mechanics of it but + + + align:start position:0% +>> and I know like the mechanics of it but +I think there I I've been told it's not + + align:start position:0% +I think there I I've been told it's not + + + align:start position:0% +I think there I I've been told it's not +necessarily the most exciting job in the + + align:start position:0% +necessarily the most exciting job in the + + + align:start position:0% +necessarily the most exciting job in the +No. Yeah, you just sit there and do your + + align:start position:0% +No. Yeah, you just sit there and do your + + + align:start position:0% +No. Yeah, you just sit there and do your +homework and every once in a while you + + align:start position:0% +homework and every once in a while you + + + align:start position:0% +homework and every once in a while you +look up + + align:start position:0% +look up + + + align:start position:0% +look up +very reasonable + + align:start position:0% +very reasonable + + + align:start position:0% +very reasonable +>> and they get paid for like I know 12 or + + align:start position:0% +>> and they get paid for like I know 12 or + + + align:start position:0% +>> and they get paid for like I know 12 or +13 bucks an hour or something. + + align:start position:0% +13 bucks an hour or something. + + + align:start position:0% +13 bucks an hour or something. +>> Yeah. So, so you know if the whole idea + + align:start position:0% +>> Yeah. So, so you know if the whole idea + + + align:start position:0% +>> Yeah. So, so you know if the whole idea +of the game is let's try try try to get + + align:start position:0% +of the game is let's try try try to get + + + align:start position:0% +of the game is let's try try try to get +as much homework done without + + align:start position:0% +as much homework done without + + + align:start position:0% +as much homework done without +>> that might be more entertaining than + + align:start position:0% +>> that might be more entertaining than + + + align:start position:0% +>> that might be more entertaining than +just like + + align:start position:0% +just like + + + align:start position:0% +just like +>> cool + + align:start position:0% +>> cool + + + align:start position:0% +>> cool +critical + + align:start position:0% +critical + + + align:start position:0% +critical +>> um + + align:start position:0% +>> um + + + align:start position:0% +>> um +but I got my problems then + + align:start position:0% +but I got my problems then + + + align:start position:0% +but I got my problems then +>> just plus one points you have to do + + align:start position:0% +>> just plus one points you have to do + + + align:start position:0% +>> just plus one points you have to do +homework while you play + + align:start position:0% +homework while you play + + + align:start position:0% +homework while you play +>> Wow + + align:start position:0% +>> Wow + + + align:start position:0% +>> Wow +Terrible be the worst game Whatever. + + align:start position:0% +Terrible be the worst game Whatever. + + + align:start position:0% +Terrible be the worst game Whatever. +What happens if you + + align:start position:0% +What happens if you + + + align:start position:0% +What happens if you +>> guys + + align:start position:0% +>> guys + + + align:start position:0% +>> guys +may be too meta at that point? + + align:start position:0% +may be too meta at that point? + + + align:start position:0% +may be too meta at that point? +>> And besides, but I think we still have a + + align:start position:0% +>> And besides, but I think we still have a + + + align:start position:0% +>> And besides, but I think we still have a +time limit like half an hour or + + align:start position:0% +time limit like half an hour or + + + align:start position:0% +time limit like half an hour or +something like that. You know, it's like + + align:start position:0% +something like that. You know, it's like + + + align:start position:0% +something like that. You know, it's like +homework. + + align:start position:0% +homework. + + + align:start position:0% +homework. +>> We have really easy homework. + + align:start position:0% + + + + align:start position:0% + +>> Um, let's see. Just a reminder for + + align:start position:0% +>> Um, let's see. Just a reminder for + + + align:start position:0% +>> Um, let's see. Just a reminder for +everyone who hasn't uh who's been + + align:start position:0% +everyone who hasn't uh who's been + + + align:start position:0% +everyone who hasn't uh who's been +falling off on the forum post, please + + align:start position:0% +falling off on the forum post, please + + + align:start position:0% +falling off on the forum post, please +make sure that you keep up on your forum + + align:start position:0% +make sure that you keep up on your forum + + + align:start position:0% +make sure that you keep up on your forum +post. Those things actually do affect + + align:start position:0% +post. Those things actually do affect + + + align:start position:0% +post. Those things actually do affect +your grade. Uh so um again we're + + align:start position:0% +your grade. Uh so um again we're + + + align:start position:0% +your grade. Uh so um again we're +expecting one in person not one team. Uh + + align:start position:0% +expecting one in person not one team. Uh + + + align:start position:0% +expecting one in person not one team. Uh +so if you have any uh opinions since + + align:start position:0% +so if you have any uh opinions since + + + align:start position:0% +so if you have any uh opinions since +we're in between reading uh assignments + + align:start position:0% +we're in between reading uh assignments + + + align:start position:0% +we're in between reading uh assignments +right right now you can write about the + + align:start position:0% +right right now you can write about the + + + align:start position:0% +right right now you can write about the +assignment but if you wrote up something + + align:start position:0% +assignment but if you wrote up something + + + align:start position:0% +assignment but if you wrote up something +let's say a reflection on how the past + + align:start position:0% +let's say a reflection on how the past + + + align:start position:0% +let's say a reflection on how the past +assignment went. You know that that's + + align:start position:0% +assignment went. You know that that's + + + align:start position:0% +assignment went. You know that that's +fine. We're not expecting more than one + + align:start position:0% +fine. We're not expecting more than one + + + align:start position:0% +fine. We're not expecting more than one +forum post a week. Of course, feel free + + align:start position:0% +forum post a week. Of course, feel free + + + align:start position:0% +forum post a week. Of course, feel free +to comment on other people's forum posts + + align:start position:0% +to comment on other people's forum posts + + + align:start position:0% +to comment on other people's forum posts +as well. And those if you want to like + + align:start position:0% +as well. And those if you want to like + + + align:start position:0% +as well. And those if you want to like +if you if there's a discussion or a + + align:start position:0% +if you if there's a discussion or a + + + align:start position:0% +if you if there's a discussion or a +point that's been raised that's kind of + + align:start position:0% +point that's been raised that's kind of + + + align:start position:0% +point that's been raised that's kind of +interesting and you want to kind of + + align:start position:0% +interesting and you want to kind of + + + align:start position:0% +interesting and you want to kind of +develop on that, you know, put some + + align:start position:0% +develop on that, you know, put some + + + align:start position:0% +develop on that, you know, put some +thought into it. Write something + + align:start position:0% +thought into it. Write something + + + align:start position:0% +thought into it. Write something +interesting that's going to keep on the + + align:start position:0% +interesting that's going to keep on the + + + align:start position:0% +interesting that's going to keep on the +conversation that that counts too. Um + + align:start position:0% +conversation that that counts too. Um + + + align:start position:0% +conversation that that counts too. Um +and and that's fine. + + align:start position:0% + + + + align:start position:0% + +Okay. So, puddles. Um + + align:start position:0% +Okay. So, puddles. Um + + + align:start position:0% +Okay. So, puddles. Um +so, Brenda's Okay. So actually before I + + align:start position:0% +so, Brenda's Okay. So actually before I + + + align:start position:0% +so, Brenda's Okay. So actually before I +start the renders, let's let's start + + align:start position:0% +start the renders, let's let's start + + + align:start position:0% +start the renders, let's let's start +with Scott's Scott. What what what were + + align:start position:0% +with Scott's Scott. What what what were + + + align:start position:0% +with Scott's Scott. What what what were +some of the definitions or some of the + + align:start position:0% +some of the definitions or some of the + + + align:start position:0% +some of the definitions or some of the +things that Scott King was mentioning + + align:start position:0% +things that Scott King was mentioning + + + align:start position:0% +things that Scott King was mentioning +that were good for puzzle design? + + align:start position:0% +that were good for puzzle design? + + + align:start position:0% +that were good for puzzle design? +>> I was reading + + align:start position:0% +>> I was reading + + + align:start position:0% +>> I was reading +>> that was in the book or not in the book. + + align:start position:0% +>> that was in the book or not in the book. + + + align:start position:0% +>> that was in the book or not in the book. +>> Uh this was the the the web page + + align:start position:0% +>> Uh this was the the the web page + + + align:start position:0% +>> Uh this was the the the web page +>> web page + + align:start position:0% +>> web page + + + align:start position:0% +>> web page +difficulty + + align:start position:0% +difficulty + + + align:start position:0% +difficulty +>> fun and has the right answer. + + align:start position:0% +>> fun and has the right answer. + + + align:start position:0% +>> fun and has the right answer. +>> Yeah, + + align:start position:0% +>> Yeah, + + + align:start position:0% +>> Yeah, +>> that's actually a solution. Yeah. could + + align:start position:0% +>> that's actually a solution. Yeah. could + + + align:start position:0% +>> that's actually a solution. Yeah. could +actually create. + + align:start position:0% +actually create. + + + align:start position:0% +actually create. +>> He he he he didn't really differentiate + + align:start position:0% +>> He he he he didn't really differentiate + + + align:start position:0% +>> He he he he didn't really differentiate +between like kind of like puzzles that + + align:start position:0% +between like kind of like puzzles that + + + align:start position:0% +between like kind of like puzzles that +could be generated uh you know like a + + align:start position:0% +could be generated uh you know like a + + + align:start position:0% +could be generated uh you know like a +sudoku or something where you have you + + align:start position:0% +sudoku or something where you have you + + + align:start position:0% +sudoku or something where you have you +kind of have an algorithm that lets you + + align:start position:0% +kind of have an algorithm that lets you + + + align:start position:0% +kind of have an algorithm that lets you +create multiple puzzles and but as long + + align:start position:0% +create multiple puzzles and but as long + + + align:start position:0% +create multiple puzzles and but as long +as that that particular iteration had + + align:start position:0% +as that that particular iteration had + + + align:start position:0% +as that that particular iteration had +right answer. Uh so that was really + + align:start position:0% +right answer. Uh so that was really + + + align:start position:0% +right answer. Uh so that was really +fair. Um anything else you remember + + align:start position:0% +fair. Um anything else you remember + + + align:start position:0% +fair. Um anything else you remember +talked a lot about difficulty. + + align:start position:0% +talked a lot about difficulty. + + + align:start position:0% +talked a lot about difficulty. +>> Mhm. make it accessible but not super + + align:start position:0% +>> Mhm. make it accessible but not super + + + align:start position:0% +>> Mhm. make it accessible but not super +easy, + + align:start position:0% +easy, + + + align:start position:0% +easy, +>> right? + + align:start position:0% +>> right? + + + align:start position:0% +>> right? +>> And targeting a specific audience. + + align:start position:0% +>> And targeting a specific audience. + + + align:start position:0% +>> And targeting a specific audience. +>> There's also the ability to uh change + + align:start position:0% +>> There's also the ability to uh change + + + align:start position:0% +>> There's also the ability to uh change +the difficulty. Was it dynamic + + align:start position:0% +the difficulty. Was it dynamic + + + align:start position:0% +the difficulty. Was it dynamic +difficulty? + + align:start position:0% +difficulty? + + + align:start position:0% +difficulty? +>> Uh so some areas may actually be easier + + align:start position:0% +>> Uh so some areas may actually be easier + + + align:start position:0% +>> Uh so some areas may actually be easier +easier settings and then actually what + + align:start position:0% +easier settings and then actually what + + + align:start position:0% +easier settings and then actually what +they want it to be in harder settings. + + align:start position:0% +they want it to be in harder settings. + + + align:start position:0% +they want it to be in harder settings. +>> I think that was Brenda's but yeah. + + align:start position:0% +>> I think that was Brenda's but yeah. + + + align:start position:0% +>> I think that was Brenda's but yeah. +There's there's also the distinction + + align:start position:0% +There's there's also the distinction + + + align:start position:0% +There's there's also the distinction +between sort of like type of difficulty + + align:start position:0% +between sort of like type of difficulty + + + align:start position:0% +between sort of like type of difficulty +like you know things where + + align:start position:0% +like you know things where + + + align:start position:0% +like you know things where +>> you know the letter puzzle that he has + + align:start position:0% +>> you know the letter puzzle that he has + + + align:start position:0% +>> you know the letter puzzle that he has +at the beginning where it requires + + align:start position:0% +at the beginning where it requires + + + align:start position:0% +at the beginning where it requires +>> sort of like thinking about it figuring + + align:start position:0% +>> sort of like thinking about it figuring + + + align:start position:0% +>> sort of like thinking about it figuring +out how + + align:start position:0% +out how + + + align:start position:0% +out how +>> yeah it's it's it was patience versus + + align:start position:0% +>> yeah it's it's it was patience versus + + + align:start position:0% +>> yeah it's it's it was patience versus +something else I can remember + + align:start position:0% +something else I can remember + + + align:start position:0% +something else I can remember +>> but then you have things like mazes + + align:start position:0% +>> but then you have things like mazes + + + align:start position:0% +>> but then you have things like mazes +where it's all patience where you have + + align:start position:0% +where it's all patience where you have + + + align:start position:0% +where it's all patience where you have +to like be very like careful and and + + align:start position:0% +to like be very like careful and and + + + align:start position:0% +to like be very like careful and and +your way through + + align:start position:0% +your way through + + + align:start position:0% +your way through +>> and sometimes they're like bringing in + + align:start position:0% +>> and sometimes they're like bringing in + + + align:start position:0% +>> and sometimes they're like bringing in +information from from other domains from + + align:start position:0% +information from from other domains from + + + align:start position:0% +information from from other domains from +outside from outside of the console it's + + align:start position:0% +outside from outside of the console it's + + + align:start position:0% +outside from outside of the console it's +just like all the information that is + + align:start position:0% +just like all the information that is + + + align:start position:0% +just like all the information that is +currently in the puzzle. Um + + align:start position:0% +currently in the puzzle. Um + + + align:start position:0% +currently in the puzzle. Um +uh but but the interesting thing about + + align:start position:0% +uh but but the interesting thing about + + + align:start position:0% +uh but but the interesting thing about +the puzzle that he particularly shows is + + align:start position:0% +the puzzle that he particularly shows is + + + align:start position:0% +the puzzle that he particularly shows is +that he shows a range of different ways + + align:start position:0% +that he shows a range of different ways + + + align:start position:0% +that he shows a range of different ways +to actually solve it. None of which are + + align:start position:0% +to actually solve it. None of which are + + + align:start position:0% +to actually solve it. None of which are +actually satisfying except for that + + align:start position:0% +actually satisfying except for that + + + align:start position:0% +actually satisfying except for that +final answer which which he irritatedly + + align:start position:0% +final answer which which he irritatedly + + + align:start position:0% +final answer which which he irritatedly +does not tell you like gives you another + + align:start position:0% +does not tell you like gives you another + + + align:start position:0% +does not tell you like gives you another +puzzle. + + align:start position:0% + + + + align:start position:0% + +Um but um you know it's kind of + + align:start position:0% +Um but um you know it's kind of + + + align:start position:0% +Um but um you know it's kind of +interesting to think about actually + + align:start position:0% +interesting to think about actually + + + align:start position:0% +interesting to think about actually +what's the audience for those kinds of + + align:start position:0% +what's the audience for those kinds of + + + align:start position:0% +what's the audience for those kinds of +specific puzzles. I mean there there are + + align:start position:0% +specific puzzles. I mean there there are + + + align:start position:0% +specific puzzles. I mean there there are +magazines out there like games magazine + + align:start position:0% +magazines out there like games magazine + + + align:start position:0% +magazines out there like games magazine +in particular but um sometimes you see + + align:start position:0% +in particular but um sometimes you see + + + align:start position:0% +in particular but um sometimes you see +um stuff nestled into magazines um uh + + align:start position:0% +um stuff nestled into magazines um uh + + + align:start position:0% +um stuff nestled into magazines um uh +that are not just about games. you see + + align:start position:0% +that are not just about games. you see + + + align:start position:0% +that are not just about games. you see +stuff like cross word puzzles and + + align:start position:0% +stuff like cross word puzzles and + + + align:start position:0% +stuff like cross word puzzles and +newspapers and everything like that and + + align:start position:0% +newspapers and everything like that and + + + align:start position:0% +newspapers and everything like that and +now things like Sudoku and all that are + + align:start position:0% +now things like Sudoku and all that are + + + align:start position:0% +now things like Sudoku and all that are +becoming way more popular um that are + + align:start position:0% +becoming way more popular um that are + + + align:start position:0% +becoming way more popular um that are +you know that are meant to be really + + align:start position:0% +you know that are meant to be really + + + align:start position:0% +you know that are meant to be really +really mass audience whereas a magazine + + align:start position:0% +really mass audience whereas a magazine + + + align:start position:0% +really mass audience whereas a magazine +that is specifically targeted at puzzle + + align:start position:0% +that is specifically targeted at puzzle + + + align:start position:0% +that is specifically targeted at puzzle +enthusiasts can be like super hardcore + + align:start position:0% +enthusiasts can be like super hardcore + + + align:start position:0% +enthusiasts can be like super hardcore +but of course if the whole magazine then + + align:start position:0% +but of course if the whole magazine then + + + align:start position:0% +but of course if the whole magazine then +you can have like a whole range of + + align:start position:0% +you can have like a whole range of + + + align:start position:0% +you can have like a whole range of +different difficulties in there you know + + align:start position:0% +different difficulties in there you know + + + align:start position:0% +different difficulties in there you know +the the assumption that you can solve + + align:start position:0% +the the assumption that you can solve + + + align:start position:0% +the the assumption that you can solve +something not so + + align:start position:0% +something not so + + + align:start position:0% +something not so +>> out of interest does anybody know like + + align:start position:0% +>> out of interest does anybody know like + + + align:start position:0% +>> out of interest does anybody know like +really actually know how people in + + align:start position:0% +really actually know how people in + + + align:start position:0% +really actually know how people in +newspapers generate cross word puzzles + + align:start position:0% +newspapers generate cross word puzzles + + + align:start position:0% +newspapers generate cross word puzzles +and pseudo puzzles? Like does anybody + + align:start position:0% +and pseudo puzzles? Like does anybody + + + align:start position:0% +and pseudo puzzles? Like does anybody +know what the actual process behind that + + align:start position:0% +know what the actual process behind that + + + align:start position:0% +know what the actual process behind that +is? Cuz I don't know, right? + + align:start position:0% +is? Cuz I don't know, right? + + + align:start position:0% +is? Cuz I don't know, right? +>> I think + + align:start position:0% +>> I think + + + align:start position:0% +>> I think +>> I mean I imagine how you might do it. + + align:start position:0% +>> I mean I imagine how you might do it. + + + align:start position:0% +>> I mean I imagine how you might do it. +You might start with the filled out + + align:start position:0% +You might start with the filled out + + + align:start position:0% +You might start with the filled out +thing and then like remove bits to get + + align:start position:0% +thing and then like remove bits to get + + + align:start position:0% +thing and then like remove bits to get +your sudoku + + align:start position:0% +your sudoku + + + align:start position:0% +your sudoku +>> or you might brute force dictionary + + align:start position:0% +>> or you might brute force dictionary + + + align:start position:0% +>> or you might brute force dictionary +search to come up with words which fit + + align:start position:0% +search to come up with words which fit + + + align:start position:0% +search to come up with words which fit +together in order for + + align:start position:0% +together in order for + + + align:start position:0% +together in order for +>> what they do with sudoku now is they + + align:start position:0% +>> what they do with sudoku now is they + + + align:start position:0% +>> what they do with sudoku now is they +have some like computer algorithm to and + + align:start position:0% +have some like computer algorithm to and + + + align:start position:0% +have some like computer algorithm to and +has scales difficulty and it generates a + + align:start position:0% +has scales difficulty and it generates a + + + align:start position:0% +has scales difficulty and it generates a +random sudoku puzzle from your input + + align:start position:0% +random sudoku puzzle from your input + + + align:start position:0% +random sudoku puzzle from your input +powerful + + align:start position:0% +powerful + + + align:start position:0% +powerful +>> sudoku is solved enough that you can + + align:start position:0% +>> sudoku is solved enough that you can + + + align:start position:0% +>> sudoku is solved enough that you can +actually just algorithmically generate + + align:start position:0% +actually just algorithmically generate + + + align:start position:0% +actually just algorithmically generate +for like + + align:start position:0% +for like + + + align:start position:0% +for like +>> a an actual ual, you know, numerical + + align:start position:0% +>> a an actual ual, you know, numerical + + + align:start position:0% +>> a an actual ual, you know, numerical +difficulty. + + align:start position:0% +difficulty. + + + align:start position:0% +difficulty. +>> You scale it from, you know, like 1 to + + align:start position:0% +>> You scale it from, you know, like 1 to + + + align:start position:0% +>> You scale it from, you know, like 1 to +10. 10 being where + + align:start position:0% +10. 10 being where + + + align:start position:0% +10. 10 being where +>> where there's like literally only one + + align:start position:0% +>> where there's like literally only one + + + align:start position:0% +>> where there's like literally only one +step to take at each point. + + align:start position:0% +step to take at each point. + + + align:start position:0% +step to take at each point. +>> Oh, the one the one that takes three + + align:start position:0% +>> Oh, the one the one that takes three + + + align:start position:0% +>> Oh, the one the one that takes three +months that took him three months to + + align:start position:0% +months that took him three months to + + + align:start position:0% +months that took him three months to +solve or something. + + align:start position:0% +solve or something. + + + align:start position:0% +solve or something. +>> But but like cross there's there's + + align:start position:0% +>> But but like cross there's there's + + + align:start position:0% +>> But but like cross there's there's +people actually just get paid to sit + + align:start position:0% +people actually just get paid to sit + + + align:start position:0% +people actually just get paid to sit +down and generate those. + + align:start position:0% +down and generate those. + + + align:start position:0% +down and generate those. +>> Will shorts + + align:start position:0% + + + + align:start position:0% + +times takes submissions from other + + align:start position:0% +times takes submissions from other + + + align:start position:0% +times takes submissions from other +people. That's why it says edited by + + align:start position:0% +people. That's why it says edited by + + + align:start position:0% +people. That's why it says edited by +Will Schwarz because people submit stuff + + align:start position:0% +Will Schwarz because people submit stuff + + + align:start position:0% +Will Schwarz because people submit stuff +and then he kind of like just touches it + + align:start position:0% +and then he kind of like just touches it + + + align:start position:0% +and then he kind of like just touches it +up. + + align:start position:0% +up. + + + align:start position:0% +up. +>> So he he kind of crowdsources cross word + + align:start position:0% +>> So he he kind of crowdsources cross word + + + align:start position:0% +>> So he he kind of crowdsources cross word +puzzle + + align:start position:0% +puzzle + + + align:start position:0% +puzzle +>> generation. I'm sure I'm sure + + align:start position:0% +>> generation. I'm sure I'm sure + + + align:start position:0% +>> generation. I'm sure I'm sure +>> in the past you had to created it own. + + align:start position:0% +>> in the past you had to created it own. + + + align:start position:0% +>> in the past you had to created it own. +>> Yeah. + + align:start position:0% +>> Yeah. + + + align:start position:0% +>> Yeah. +>> But I mean so the difficulty in a cross + + align:start position:0% +>> But I mean so the difficulty in a cross + + + align:start position:0% +>> But I mean so the difficulty in a cross +word puzzle isn't just like in the sort + + align:start position:0% +word puzzle isn't just like in the sort + + + align:start position:0% +word puzzle isn't just like in the sort +of geometric layout of how the words the + + align:start position:0% +of geometric layout of how the words the + + + align:start position:0% +of geometric layout of how the words the +words go is the the specific clues that + + align:start position:0% +words go is the the specific clues that + + + align:start position:0% +words go is the the specific clues that +they give you can be more or less + + align:start position:0% +they give you can be more or less + + + align:start position:0% +they give you can be more or less +obuscated in some ways. And New York + + align:start position:0% +obuscated in some ways. And New York + + + align:start position:0% +obuscated in some ways. And New York +Times in particular with this is, you + + align:start position:0% +Times in particular with this is, you + + + align:start position:0% +Times in particular with this is, you +know, they they'll give you like two + + align:start position:0% +know, they they'll give you like two + + + align:start position:0% +know, they they'll give you like two +words that don't that that with with no + + align:start position:0% +words that don't that that with with no + + + align:start position:0% +words that don't that that with with no +grammatical context about how that's + + align:start position:0% +grammatical context about how that's + + + align:start position:0% +grammatical context about how that's +supposed to fit in. + + align:start position:0% +supposed to fit in. + + + align:start position:0% +supposed to fit in. +>> Well, it gets harder during the week. + + align:start position:0% +>> Well, it gets harder during the week. + + + align:start position:0% +>> Well, it gets harder during the week. +So, + + align:start position:0% +So, + + + align:start position:0% +So, +>> yeah. + + align:start position:0% +>> yeah. + + + align:start position:0% +>> yeah. +>> Yeah. So, so so and and and so you you + + align:start position:0% +>> Yeah. So, so so and and and so you you + + + align:start position:0% +>> Yeah. So, so so and and and so you you +you can actually compare and see how + + align:start position:0% +you can actually compare and see how + + + align:start position:0% +you can actually compare and see how +that difficulty scaling is just by + + align:start position:0% +that difficulty scaling is just by + + + align:start position:0% +that difficulty scaling is just by +looking at the clues, not even looking + + align:start position:0% +looking at the clues, not even looking + + + align:start position:0% +looking at the clues, not even looking +at the puzzle itself. Um and of course + + align:start position:0% +at the puzzle itself. Um and of course + + + align:start position:0% +at the puzzle itself. Um and of course +the other thing about crosswords is uh + + align:start position:0% +the other thing about crosswords is uh + + + align:start position:0% +the other thing about crosswords is uh +you know just just to bring up a point + + align:start position:0% +you know just just to bring up a point + + + align:start position:0% +you know just just to bring up a point +that we talked about in earlier class + + align:start position:0% +that we talked about in earlier class + + + align:start position:0% +that we talked about in earlier class +you know it's that the cross words that + + align:start position:0% +you know it's that the cross words that + + + align:start position:0% +you know it's that the cross words that +we're familiar with at least are + + align:start position:0% +we're familiar with at least are + + + align:start position:0% +we're familiar with at least are +dependent on the redundancy of the + + align:start position:0% +dependent on the redundancy of the + + + align:start position:0% +dependent on the redundancy of the +English language right you know there + + align:start position:0% +English language right you know there + + + align:start position:0% +English language right you know there +you don't need every single letter in a + + align:start position:0% +you don't need every single letter in a + + + align:start position:0% +you don't need every single letter in a +in of a word in order to figure out what + + align:start position:0% +in of a word in order to figure out what + + + align:start position:0% +in of a word in order to figure out what +that word is so that if there's a word + + align:start position:0% +that word is so that if there's a word + + + align:start position:0% +that word is so that if there's a word +that you couldn't otherwise have gotten + + align:start position:0% +that you couldn't otherwise have gotten + + + align:start position:0% +that you couldn't otherwise have gotten +from the clue you can still get it just + + align:start position:0% +from the clue you can still get it just + + + align:start position:0% +from the clue you can still get it just +by seeing the letters that are available + + align:start position:0% +by seeing the letters that are available + + + align:start position:0% +by seeing the letters that are available +that's because English language is kind + + align:start position:0% +that's because English language is kind + + + align:start position:0% +that's because English language is kind +of about 50% redundant information. If + + align:start position:0% +of about 50% redundant information. If + + + align:start position:0% +of about 50% redundant information. If +you dropped every single vowel in in in + + align:start position:0% +you dropped every single vowel in in in + + + align:start position:0% +you dropped every single vowel in in in +in a sentence, you could probably still + + align:start position:0% +in a sentence, you could probably still + + + align:start position:0% +in a sentence, you could probably still +make out what that sentence said. And + + align:start position:0% +make out what that sentence said. And + + + align:start position:0% +make out what that sentence said. And +you don't necessarily get that with + + align:start position:0% +you don't necessarily get that with + + + align:start position:0% +you don't necessarily get that with +Chinese, for instance. + + align:start position:0% +Chinese, for instance. + + + align:start position:0% +Chinese, for instance. +How many folks here have like some or + + align:start position:0% +How many folks here have like some or + + + align:start position:0% +How many folks here have like some or +there probably are other languages here + + align:start position:0% +there probably are other languages here + + + align:start position:0% +there probably are other languages here +where like every single character can + + align:start position:0% +where like every single character can + + + align:start position:0% +where like every single character can +mean means a word or something like + + align:start position:0% +mean means a word or something like + + + align:start position:0% +mean means a word or something like +that? + + align:start position:0% +that? + + + align:start position:0% +that? +>> Hebrew has no vows, right? + + align:start position:0% +>> Hebrew has no vows, right? + + + align:start position:0% +>> Hebrew has no vows, right? +>> Well, they do like third grade and they + + align:start position:0% +>> Well, they do like third grade and they + + + align:start position:0% +>> Well, they do like third grade and they +start dropping them after that. So it's + + align:start position:0% +start dropping them after that. So it's + + + align:start position:0% +start dropping them after that. So it's +basically because it is understandable + + align:start position:0% +basically because it is understandable + + + align:start position:0% +basically because it is understandable +without vowels, you eventually just stop + + align:start position:0% +without vowels, you eventually just stop + + + align:start position:0% +without vowels, you eventually just stop +using them. + + align:start position:0% +using them. + + + align:start position:0% +using them. +>> Oh yeah. So that's interesting. If you + + align:start position:0% +>> Oh yeah. So that's interesting. If you + + + align:start position:0% +>> Oh yeah. So that's interesting. If you +had a cross word in Hebrew that where + + align:start position:0% +had a cross word in Hebrew that where + + + align:start position:0% +had a cross word in Hebrew that where +you expected to write in the words with + + align:start position:0% +you expected to write in the words with + + + align:start position:0% +you expected to write in the words with +vowels, you probably could actually uh + + align:start position:0% +vowels, you probably could actually uh + + + align:start position:0% +vowels, you probably could actually uh +do it one very similar to to an English + + align:start position:0% +do it one very similar to to an English + + + align:start position:0% +do it one very similar to to an English +one. + + align:start position:0% +one. + + + align:start position:0% +one. +>> It's difficult because the vowels in + + align:start position:0% +>> It's difficult because the vowels in + + + align:start position:0% +>> It's difficult because the vowels in +Hebrew are attached to a letter, not a + + align:start position:0% +Hebrew are attached to a letter, not a + + + align:start position:0% +Hebrew are attached to a letter, not a +separate character. + + align:start position:0% +separate character. + + + align:start position:0% +separate character. +>> Below letters or barow. + + align:start position:0% +>> Below letters or barow. + + + align:start position:0% +>> Below letters or barow. +>> No. + + align:start position:0% + + + + align:start position:0% + +But you wonder if in the in a cross word + + align:start position:0% +But you wonder if in the in a cross word + + + align:start position:0% +But you wonder if in the in a cross word +in a letter can make a different sound + + align:start position:0% +in a letter can make a different sound + + + align:start position:0% +in a letter can make a different sound +with both. + + align:start position:0% +with both. + + + align:start position:0% +with both. +>> Mhm. + + align:start position:0% +>> Mhm. + + + align:start position:0% +>> Mhm. +>> Soft C or hard C + + align:start position:0% +>> Soft C or hard C + + + align:start position:0% +>> Soft C or hard C +>> because a V can be vo or va or they you + + align:start position:0% +>> because a V can be vo or va or they you + + + align:start position:0% +>> because a V can be vo or va or they you +don't know. You only know by context. + + align:start position:0% +don't know. You only know by context. + + + align:start position:0% +don't know. You only know by context. +>> English like C could be a hard soft + + align:start position:0% +>> English like C could be a hard soft + + + align:start position:0% +>> English like C could be a hard soft +>> or G could be J. + + align:start position:0% +>> or G could be J. + + + align:start position:0% +>> or G could be J. +>> Yeah. + + align:start position:0% +>> Yeah. + + + align:start position:0% +>> Yeah. +>> Yeah. It's true. that although in + + align:start position:0% +>> Yeah. It's true. that although in + + + align:start position:0% +>> Yeah. It's true. that although in +English in particular the phonetic + + align:start position:0% +English in particular the phonetic + + + align:start position:0% +English in particular the phonetic +meaning + + align:start position:0% +meaning + + + align:start position:0% +meaning +the the way how a certain word is + + align:start position:0% +the the way how a certain word is + + + align:start position:0% +the the way how a certain word is +pronounced isn't necessarily uh isn't + + align:start position:0% +pronounced isn't necessarily uh isn't + + + align:start position:0% +pronounced isn't necessarily uh isn't +necessarily essential for solving a + + align:start position:0% +necessarily essential for solving a + + + align:start position:0% +necessarily essential for solving a +puzzle puzzle unless the clues happen to + + align:start position:0% +puzzle puzzle unless the clues happen to + + + align:start position:0% +puzzle puzzle unless the clues happen to +be phonetic clues you know sounds like a + + align:start position:0% +be phonetic clues you know sounds like a + + + align:start position:0% +be phonetic clues you know sounds like a +fish uh so so so + + align:start position:0% +fish uh so so so + + + align:start position:0% +fish uh so so so +that may not come in so much play when + + align:start position:0% +that may not come in so much play when + + + align:start position:0% +that may not come in so much play when +it comes to English in particular + + align:start position:0% +it comes to English in particular + + + align:start position:0% +it comes to English in particular +>> um Jason you had your hand up earlier + + align:start position:0% +>> um Jason you had your hand up earlier + + + align:start position:0% +>> um Jason you had your hand up earlier +about + + align:start position:0% +about + + + align:start position:0% +about +>> it There's going to be count + + align:start position:0% +>> it There's going to be count + + + align:start position:0% +>> it There's going to be count +algorithmically generated. + + align:start position:0% +algorithmically generated. + + + align:start position:0% +algorithmically generated. +>> Well, also one thing about algorithmic + + align:start position:0% +>> Well, also one thing about algorithmic + + + align:start position:0% +>> Well, also one thing about algorithmic +about Sudoku difficulty, a lot of it + + align:start position:0% +about Sudoku difficulty, a lot of it + + + align:start position:0% +about Sudoku difficulty, a lot of it +comes on the selective removal of + + align:start position:0% +comes on the selective removal of + + + align:start position:0% +comes on the selective removal of +numbers. It's not what is the final + + align:start position:0% +numbers. It's not what is the final + + + align:start position:0% +numbers. It's not what is the final +number, the final pattern going to look + + align:start position:0% +number, the final pattern going to look + + + align:start position:0% +number, the final pattern going to look +like. That's actually the difficulty. + + align:start position:0% +like. That's actually the difficulty. + + + align:start position:0% +like. That's actually the difficulty. +It's how do we remove the numbers in a + + align:start position:0% +It's how do we remove the numbers in a + + + align:start position:0% +It's how do we remove the numbers in a +way that gives multiple possible answers + + align:start position:0% +way that gives multiple possible answers + + + align:start position:0% +way that gives multiple possible answers +uh or multiple possible dead ends uh + + align:start position:0% +uh or multiple possible dead ends uh + + + align:start position:0% +uh or multiple possible dead ends uh +because really there's only one solution + + align:start position:0% +because really there's only one solution + + + align:start position:0% +because really there's only one solution +at the end of it. Um I'm not actually + + align:start position:0% +at the end of it. Um I'm not actually + + + align:start position:0% +at the end of it. Um I'm not actually +familiar with the algorithm which does + + align:start position:0% +familiar with the algorithm which does + + + align:start position:0% +familiar with the algorithm which does +so but it seems to be very clear that + + align:start position:0% +so but it seems to be very clear that + + + align:start position:0% +so but it seems to be very clear that +there are at least two algorithms. One + + align:start position:0% +there are at least two algorithms. One + + + align:start position:0% +there are at least two algorithms. One +of which is very easy which is just + + align:start position:0% +of which is very easy which is just + + + align:start position:0% +of which is very easy which is just +provide a a legitimate pseudogu solution + + align:start position:0% +provide a a legitimate pseudogu solution + + + align:start position:0% +provide a a legitimate pseudogu solution +and then one slightly harder is which + + align:start position:0% +and then one slightly harder is which + + + align:start position:0% +and then one slightly harder is which +now which numbers to be removed so that + + align:start position:0% +now which numbers to be removed so that + + + align:start position:0% +now which numbers to be removed so that +it's still solvable. + + align:start position:0% +it's still solvable. + + + align:start position:0% +it's still solvable. +Um can people take picross? Um yeah, + + align:start position:0% +Um can people take picross? Um yeah, + + + align:start position:0% +Um can people take picross? Um yeah, +>> some someone want to describe it for the + + align:start position:0% +>> some someone want to describe it for the + + + align:start position:0% +>> some someone want to describe it for the +folks who haven't aren't familiar with + + align:start position:0% +folks who haven't aren't familiar with + + + align:start position:0% +folks who haven't aren't familiar with +with with it. We can use the whiteboard. + + align:start position:0% +with with it. We can use the whiteboard. + + + align:start position:0% +with with it. We can use the whiteboard. +>> Sure. + + align:start position:0% +>> Sure. + + + align:start position:0% +>> Sure. +>> Um I think on the + + align:start position:0% +>> Um I think on the + + + align:start position:0% +>> Um I think on the +>> I think the green one works better. + + align:start position:0% +>> I think the green one works better. + + + align:start position:0% +>> I think the green one works better. +>> Yeah, I remember read + + align:start position:0% +>> Yeah, I remember read + + + align:start position:0% +>> Yeah, I remember read +only familiar across 3D. + + align:start position:0% + + + + align:start position:0% + +Yeah, that's the best way. + + align:start position:0% +Yeah, that's the best way. + + + align:start position:0% +Yeah, that's the best way. +>> Sorry to put you on the spot. + + align:start position:0% + + + + align:start position:0% + +>> The idea is that you'll have words and + + align:start position:0% +>> The idea is that you'll have words and + + + align:start position:0% +>> The idea is that you'll have words and +poems + + align:start position:0% +poems + + + align:start position:0% +poems +>> and then they'll have some number. + + align:start position:0% +>> and then they'll have some number. + + + align:start position:0% +>> and then they'll have some number. +>> Oh, this + + align:start position:0% + + + + align:start position:0% + +>> this one you fill in the blocks. + + align:start position:0% +>> this one you fill in the blocks. + + + align:start position:0% +>> this one you fill in the blocks. +>> Okay. And then and then given this + + align:start position:0% +>> Okay. And then and then given this + + + align:start position:0% +>> Okay. And then and then given this +information we have to work out which of + + align:start position:0% +information we have to work out which of + + + align:start position:0% +information we have to work out which of +these blocks is filled and which can be + + align:start position:0% +these blocks is filled and which can be + + + align:start position:0% +these blocks is filled and which can be +removed. + + align:start position:0% +removed. + + + align:start position:0% +removed. +>> And the idea is that + + align:start position:0% +>> And the idea is that + + + align:start position:0% +>> And the idea is that +>> the numbers + + align:start position:0% +>> the numbers + + + align:start position:0% +>> the numbers +>> the number tells you the number of + + align:start position:0% +>> the number tells you the number of + + + align:start position:0% +>> the number tells you the number of +blocks in that row or column which has a + + align:start position:0% +blocks in that row or column which has a + + + align:start position:0% +blocks in that row or column which has a +filled block in it. + + align:start position:0% +filled block in it. + + + align:start position:0% +filled block in it. +>> So it's like + + align:start position:0% +>> So it's like + + + align:start position:0% +>> So it's like +>> so in this case like + + align:start position:0% +>> so in this case like + + + align:start position:0% +>> so in this case like +>> they're also given + + align:start position:0% +>> they're also given + + + align:start position:0% +>> they're also given +>> nothing in this column + + align:start position:0% +>> nothing in this column + + + align:start position:0% +>> nothing in this column +this column and that column can have + + align:start position:0% +this column and that column can have + + + align:start position:0% +this column and that column can have +anything in it. Um and this is probably + + align:start position:0% +anything in it. Um and this is probably + + + align:start position:0% +anything in it. Um and this is probably +not actually example because it's + + align:start position:0% +not actually example because it's + + + align:start position:0% +not actually example because it's +probably the numbers are + + align:start position:0% +probably the numbers are + + + align:start position:0% +probably the numbers are +>> the subs are not the same. + + align:start position:0% +>> the subs are not the same. + + + align:start position:0% +>> the subs are not the same. +>> But yeah, + + align:start position:0% +>> But yeah, + + + align:start position:0% +>> But yeah, +>> so + + align:start position:0% +>> so + + + align:start position:0% +>> so +you get the idea. + + align:start position:0% +you get the idea. + + + align:start position:0% +you get the idea. +>> It's not going to work, but you get the + + align:start position:0% +>> It's not going to work, but you get the + + + align:start position:0% +>> It's not going to work, but you get the +idea. And then things can get more + + align:start position:0% +idea. And then things can get more + + + align:start position:0% +idea. And then things can get more +complicated. So the + + align:start position:0% +complicated. So the + + + align:start position:0% +complicated. So the +>> additionally, if there's just I think a + + align:start position:0% +>> additionally, if there's just I think a + + + align:start position:0% +>> additionally, if there's just I think a +three, then it means that there's a + + align:start position:0% +three, then it means that there's a + + + align:start position:0% +three, then it means that there's a +connected block of three. So for + + align:start position:0% +connected block of three. So for + + + align:start position:0% +connected block of three. So for +instance, this that and that might all + + align:start position:0% +instance, this that and that might all + + + align:start position:0% +instance, this that and that might all +have to be. Um, but if there's a three, + + align:start position:0% +have to be. Um, but if there's a three, + + + align:start position:0% +have to be. Um, but if there's a three, +which I think is in like a square or + + align:start position:0% +which I think is in like a square or + + + align:start position:0% +which I think is in like a square or +something along these lines, that means + + align:start position:0% +something along these lines, that means + + + align:start position:0% +something along these lines, that means +that there are three in that column, but + + align:start position:0% +that there are three in that column, but + + + align:start position:0% +that there are three in that column, but +there's a gap in there somewhere. And + + align:start position:0% +there's a gap in there somewhere. And + + + align:start position:0% +there's a gap in there somewhere. And +then if it's like a three in a circle or + + align:start position:0% +then if it's like a three in a circle or + + + align:start position:0% +then if it's like a three in a circle or +something else complicated like that, + + align:start position:0% +something else complicated like that, + + + align:start position:0% +something else complicated like that, +then it means that there are three, but + + align:start position:0% +then it means that there are three, but + + + align:start position:0% +then it means that there are three, but +they all have gaps between + + align:start position:0% +they all have gaps between + + + align:start position:0% +they all have gaps between +where they have a list of numbers and + + align:start position:0% +where they have a list of numbers and + + + align:start position:0% +where they have a list of numbers and +those are the + + align:start position:0% +those are the + + + align:start position:0% +those are the +>> there are consecutive blocks of that + + align:start position:0% +>> there are consecutive blocks of that + + + align:start position:0% +>> there are consecutive blocks of that +length. Yeah. + + align:start position:0% +length. Yeah. + + + align:start position:0% +length. Yeah. +>> So, so, so, so for one column you might + + align:start position:0% +>> So, so, so, so for one column you might + + + align:start position:0% +>> So, so, so, so for one column you might +say like 2 three five which means there + + align:start position:0% +say like 2 three five which means there + + + align:start position:0% +say like 2 three five which means there +is a block of two followed by a block of + + align:start position:0% +is a block of two followed by a block of + + + align:start position:0% +is a block of two followed by a block of +three followed by a block of five + + align:start position:0% +three followed by a block of five + + + align:start position:0% +three followed by a block of five +>> and they have to have a gap between them + + align:start position:0% +>> and they have to have a gap between them + + + align:start position:0% +>> and they have to have a gap between them +>> and they will have a gap in between + + align:start position:0% +>> and they will have a gap in between + + + align:start position:0% +>> and they will have a gap in between +them. So, it's not like if there's + + align:start position:0% +them. So, it's not like if there's + + + align:start position:0% +them. So, it's not like if there's +actually a block of eight in there + + align:start position:0% +actually a block of eight in there + + + align:start position:0% +actually a block of eight in there +somewhere. + + align:start position:0% +somewhere. + + + align:start position:0% +somewhere. +>> But but that's the but the whole idea is + + align:start position:0% +>> But but that's the but the whole idea is + + + align:start position:0% +>> But but that's the but the whole idea is +that you know you've got this um + + align:start position:0% +that you know you've got this um + + + align:start position:0% +that you know you've got this um +information that that is actually + + align:start position:0% +information that that is actually + + + align:start position:0% +information that that is actually +redundant. you know, you've got more + + align:start position:0% +redundant. you know, you've got more + + + align:start position:0% +redundant. you know, you've got more +information in there than you + + align:start position:0% +information in there than you + + + align:start position:0% +information in there than you +necessarily need to be able to figure + + align:start position:0% +necessarily need to be able to figure + + + align:start position:0% +necessarily need to be able to figure +out which blocks in the solution should + + align:start position:0% +out which blocks in the solution should + + + align:start position:0% +out which blocks in the solution should +be filled and when it should be empty, + + align:start position:0% +be filled and when it should be empty, + + + align:start position:0% +be filled and when it should be empty, +but you know, it's presented to you in + + align:start position:0% +but you know, it's presented to you in + + + align:start position:0% +but you know, it's presented to you in +this opuscated way. The the evidence the + + align:start position:0% +this opuscated way. The the evidence the + + + align:start position:0% +this opuscated way. The the evidence the +the clues that are given to you in a way + + align:start position:0% +the clues that are given to you in a way + + + align:start position:0% +the clues that are given to you in a way +that you know that requires you to + + align:start position:0% +that you know that requires you to + + + align:start position:0% +that you know that requires you to +perform these algorithms in order to + + align:start position:0% +perform these algorithms in order to + + + align:start position:0% +perform these algorithms in order to +figure out which one is created and + + align:start position:0% +figure out which one is created and + + + align:start position:0% +figure out which one is created and +usually that's an algorithm that you can + + align:start position:0% +usually that's an algorithm that you can + + + align:start position:0% +usually that's an algorithm that you can +use yourself. Uh although you know like + + align:start position:0% +use yourself. Uh although you know like + + + align:start position:0% +use yourself. Uh although you know like +um I think Kim was the one who was + + align:start position:0% +um I think Kim was the one who was + + + align:start position:0% +um I think Kim was the one who was +talking about pattern matching although + + align:start position:0% +talking about pattern matching although + + + align:start position:0% +talking about pattern matching although +was + + align:start position:0% +was + + + align:start position:0% +was +uh but you know eventually as you get + + align:start position:0% +uh but you know eventually as you get + + + align:start position:0% +uh but you know eventually as you get +good at these things you start to you + + align:start position:0% +good at these things you start to you + + + align:start position:0% +good at these things you start to you +you start to recognize patterns right + + align:start position:0% +you start to recognize patterns right + + + align:start position:0% +you start to recognize patterns right +off the bat right like that's a zero oh + + align:start position:0% +off the bat right like that's a zero oh + + + align:start position:0% +off the bat right like that's a zero oh +wow okay so that entire row is empty + + align:start position:0% +wow okay so that entire row is empty + + + align:start position:0% +wow okay so that entire row is empty +that that that's that's that's the sort + + align:start position:0% +that that that's that's that's the sort + + + align:start position:0% +that that that's that's that's the sort +of thing that you that becomes automatic + + align:start position:0% +of thing that you that becomes automatic + + + align:start position:0% +of thing that you that becomes automatic +after you you you + + align:start position:0% + + + + align:start position:0% + +>> um so let's see I'm not sure if I much + + align:start position:0% +>> um so let's see I'm not sure if I much + + + align:start position:0% +>> um so let's see I'm not sure if I much +more to talk about Scott Kim, but you + + align:start position:0% +more to talk about Scott Kim, but you + + + align:start position:0% +more to talk about Scott Kim, but you +know these are these are more like + + align:start position:0% +know these are these are more like + + + align:start position:0% +know these are these are more like +generated stuff. Tip over has + + align:start position:0% +generated stuff. Tip over has + + + align:start position:0% +generated stuff. Tip over has +so this is this basically is um it's + + align:start position:0% +so this is this basically is um it's + + + align:start position:0% +so this is this basically is um it's +along the lines of what uh Scott Pin uh + + align:start position:0% +along the lines of what uh Scott Pin uh + + + align:start position:0% +along the lines of what uh Scott Pin uh +is talking about, but obviously this is + + align:start position:0% +is talking about, but obviously this is + + + align:start position:0% +is talking about, but obviously this is +more physical, not a pen and paper kind + + align:start position:0% +more physical, not a pen and paper kind + + + align:start position:0% +more physical, not a pen and paper kind +of thing. + + align:start position:0% +of thing. + + + align:start position:0% +of thing. +>> Can you move for the coffee yet? + + align:start position:0% +>> Can you move for the coffee yet? + + + align:start position:0% +>> Can you move for the coffee yet? +>> Oh, move the coffee. + + align:start position:0% +>> Oh, move the coffee. + + + align:start position:0% +>> Oh, move the coffee. +>> No, I just want you to look at this. + + align:start position:0% +>> No, I just want you to look at this. + + + align:start position:0% +>> No, I just want you to look at this. +>> Okay, good. + + align:start position:0% +>> Okay, good. + + + align:start position:0% +>> Okay, good. +Look at this first. Don't look at that. + + align:start position:0% +Look at this first. Don't look at that. + + + align:start position:0% +Look at this first. Don't look at that. +Uh don't look at that. Um so the basic + + align:start position:0% +Uh don't look at that. Um so the basic + + + align:start position:0% +Uh don't look at that. Um so the basic +idea is let me just start with one. Um + + align:start position:0% +idea is let me just start with one. Um + + + align:start position:0% +idea is let me just start with one. Um +you get a card that's actually a a + + align:start position:0% +you get a card that's actually a a + + + align:start position:0% +you get a card that's actually a a +puzzle. Um I wish we were doing this + + align:start position:0% +puzzle. Um I wish we were doing this + + + align:start position:0% +puzzle. Um I wish we were doing this +outside now because I could have zoomed + + align:start position:0% +outside now because I could have zoomed + + + align:start position:0% +outside now because I could have zoomed +this out. Um but the puzzle basically + + align:start position:0% +this out. Um but the puzzle basically + + + align:start position:0% +this out. Um but the puzzle basically +just tells you how you're supposed to + + align:start position:0% +just tells you how you're supposed to + + + align:start position:0% +just tells you how you're supposed to +set up your board initially. So there's + + align:start position:0% +set up your board initially. So there's + + + align:start position:0% +set up your board initially. So there's +a Oops, wrong. + + align:start position:0% +a Oops, wrong. + + + align:start position:0% +a Oops, wrong. +There's a green guy there. There's a + + align:start position:0% +There's a green guy there. There's a + + + align:start position:0% +There's a green guy there. There's a +green guy there. This is supposed to be + + align:start position:0% +green guy there. This is supposed to be + + + align:start position:0% +green guy there. This is supposed to be +an easy puzzle. I hope it is because I'm + + align:start position:0% +an easy puzzle. I hope it is because I'm + + + align:start position:0% +an easy puzzle. I hope it is because I'm +really bad at this. + + align:start position:0% +really bad at this. + + + align:start position:0% +really bad at this. +Red guy goes there, I think. Yeah. And + + align:start position:0% +Red guy goes there, I think. Yeah. And + + + align:start position:0% +Red guy goes there, I think. Yeah. And +that's the puzzle. + + align:start position:0% +that's the puzzle. + + + align:start position:0% +that's the puzzle. +And then and there's one with a little + + align:start position:0% +And then and there's one with a little + + + align:start position:0% +And then and there's one with a little +square on it and then you have this + + align:start position:0% +square on it and then you have this + + + align:start position:0% +square on it and then you have this +chat. What? + + align:start position:0% +chat. What? + + + align:start position:0% +chat. What? +>> That's cool. + + align:start position:0% +>> That's cool. + + + align:start position:0% +>> That's cool. +>> That's awesome. So the basic idea is you + + align:start position:0% +>> That's awesome. So the basic idea is you + + + align:start position:0% +>> That's awesome. So the basic idea is you +tip over the pieces so that um so that + + align:start position:0% +tip over the pieces so that um so that + + + align:start position:0% +tip over the pieces so that um so that +the guy moves um and you don't want to + + align:start position:0% +the guy moves um and you don't want to + + + align:start position:0% +the guy moves um and you don't want to +be tipping over the pieces in a way + + align:start position:0% +be tipping over the pieces in a way + + + align:start position:0% +be tipping over the pieces in a way +where uh the um where the guy can't move + + align:start position:0% +where uh the um where the guy can't move + + + align:start position:0% +where uh the um where the guy can't move +anymore. + + align:start position:0% +anymore. + + + align:start position:0% +anymore. +>> Um + + align:start position:0% + + + + align:start position:0% + +>> yeah. So you're you're tipping over + + align:start position:0% +>> yeah. So you're you're tipping over + + + align:start position:0% +>> yeah. So you're you're tipping over +things to make a path that he can walk + + align:start position:0% +things to make a path that he can walk + + + align:start position:0% +things to make a path that he can walk +along, right? + + align:start position:0% +along, right? + + + align:start position:0% +along, right? +>> Yeah. + + align:start position:0% +>> Yeah. + + + align:start position:0% +>> Yeah. +>> And then make a closed loop + + align:start position:0% +>> And then make a closed loop + + + align:start position:0% +>> And then make a closed loop +>> and he has to touch every piece. + + align:start position:0% +>> and he has to touch every piece. + + + align:start position:0% +>> and he has to touch every piece. +>> I think he just has to get to this one + + align:start position:0% +>> I think he just has to get to this one + + + align:start position:0% +>> I think he just has to get to this one +get to the red one. Um, + + align:start position:0% +get to the red one. Um, + + + align:start position:0% +get to the red one. Um, +>> there's a plus mark. + + align:start position:0% +>> there's a plus mark. + + + align:start position:0% +>> there's a plus mark. +>> So, knock it that way and then green + + align:start position:0% +>> So, knock it that way and then green + + + align:start position:0% +>> So, knock it that way and then green +this way. + + align:start position:0% +this way. + + + align:start position:0% +this way. +>> Yeah. Yes, I agree. + + align:start position:0% +>> Yeah. Yes, I agree. + + + align:start position:0% +>> Yeah. Yes, I agree. +>> Yeah. I'm not exactly sure how to solve + + align:start position:0% +>> Yeah. I'm not exactly sure how to solve + + + align:start position:0% +>> Yeah. I'm not exactly sure how to solve +this one. + + align:start position:0% +this one. + + + align:start position:0% +this one. +>> So, yellow that way, green. + + align:start position:0% +>> So, yellow that way, green. + + + align:start position:0% +>> So, yellow that way, green. +>> Yeah. + + align:start position:0% +>> Yeah. + + + align:start position:0% +>> Yeah. +>> Yellow that way. + + align:start position:0% +>> Yellow that way. + + + align:start position:0% +>> Yellow that way. +>> Yeah. + + align:start position:0% +>> Yeah. + + + align:start position:0% +>> Yeah. +>> Wait, you're allowed to tip him over? + + align:start position:0% +>> Wait, you're allowed to tip him over? + + + align:start position:0% +>> Wait, you're allowed to tip him over? +>> Yeah. + + align:start position:0% +>> Yeah. + + + align:start position:0% +>> Yeah. +>> Did he die? + + align:start position:0% +>> Did he die? + + + align:start position:0% +>> Did he die? +>> My understanding is that he needs to + + align:start position:0% +>> My understanding is that he needs to + + + align:start position:0% +>> My understanding is that he needs to +fall onto another piece actually. + + align:start position:0% +fall onto another piece actually. + + + align:start position:0% +fall onto another piece actually. +>> Oh, so let let me just confirm I set + + align:start position:0% +>> Oh, so let let me just confirm I set + + + align:start position:0% +>> Oh, so let let me just confirm I set +this up right actually. Yeah, I did. + + align:start position:0% +this up right actually. Yeah, I did. + + + align:start position:0% +this up right actually. Yeah, I did. +>> No. So, you push the yellow that way and + + align:start position:0% +>> No. So, you push the yellow that way and + + + align:start position:0% +>> No. So, you push the yellow that way and +then the green that way and the other + + align:start position:0% +then the green that way and the other + + + align:start position:0% +then the green that way and the other +green that way. + + align:start position:0% +green that way. + + + align:start position:0% +green that way. +So with the yellow one goes. + + align:start position:0% +So with the yellow one goes. + + + align:start position:0% +So with the yellow one goes. +>> So do the green ones first. + + align:start position:0% +>> So do the green ones first. + + + align:start position:0% +>> So do the green ones first. +>> Yeah. I don't understand the rules for + + align:start position:0% +>> Yeah. I don't understand the rules for + + + align:start position:0% +>> Yeah. I don't understand the rules for +yellow. + + align:start position:0% +yellow. + + + align:start position:0% +yellow. +>> Exactly. And then + + align:start position:0% +>> Exactly. And then + + + align:start position:0% +>> Exactly. And then +>> there. + + align:start position:0% +>> there. + + + align:start position:0% +>> there. +>> No, it doesn't. + + align:start position:0% +>> No, it doesn't. + + + align:start position:0% +>> No, it doesn't. +>> Yeah. I I + + align:start position:0% +>> Yeah. I I + + + align:start position:0% +>> Yeah. I I +>> How does he + + align:start position:0% + + + + align:start position:0% + +Yeah, he he's he's actually allowed to + + align:start position:0% +Yeah, he he's he's actually allowed to + + + align:start position:0% +Yeah, he he's he's actually allowed to +move on anything that that's + + align:start position:0% +move on anything that that's + + + align:start position:0% +move on anything that that's +continuously connected. So as long as + + align:start position:0% +continuously connected. So as long as + + + align:start position:0% +continuously connected. So as long as +you can continuously + + align:start position:0% +you can continuously + + + align:start position:0% +you can continuously +connect up to this, you're fine. So tip + + align:start position:0% +connect up to this, you're fine. So tip + + + align:start position:0% +connect up to this, you're fine. So tip +tip the second green over. + + align:start position:0% +tip the second green over. + + + align:start position:0% +tip the second green over. +>> So tip that first green. + + align:start position:0% +>> So tip that first green. + + + align:start position:0% +>> So tip that first green. +>> No other way. + + align:start position:0% +>> No other way. + + + align:start position:0% +>> No other way. +>> Yeah. + + align:start position:0% +>> Yeah. + + + align:start position:0% +>> Yeah. +>> Doesn't that wrong path right now? If + + align:start position:0% +>> Doesn't that wrong path right now? If + + + align:start position:0% +>> Doesn't that wrong path right now? If +you tip that. + + align:start position:0% + + + + align:start position:0% + +>> Are you sure tipping over means move on + + align:start position:0% +>> Are you sure tipping over means move on + + + align:start position:0% +>> Are you sure tipping over means move on +spot or not? + + align:start position:0% +spot or not? + + + align:start position:0% +spot or not? +>> Well, if it doesn't then you can't reach + + align:start position:0% +>> Well, if it doesn't then you can't reach + + + align:start position:0% +>> Well, if it doesn't then you can't reach +the red effort. Yeah, I am absolutely + + align:start position:0% +the red effort. Yeah, I am absolutely + + + align:start position:0% +the red effort. Yeah, I am absolutely +sure it means that you're supposed to + + align:start position:0% +sure it means that you're supposed to + + + align:start position:0% +sure it means that you're supposed to +tip it over in a way that might be a + + align:start position:0% +tip it over in a way that might be a + + + align:start position:0% +tip it over in a way that might be a +>> screw. Tip the yellow over first and + + align:start position:0% +>> screw. Tip the yellow over first and + + + align:start position:0% +>> screw. Tip the yellow over first and +move the move the guy onto the green, + + align:start position:0% +move the move the guy onto the green, + + + align:start position:0% +move the move the guy onto the green, +then tip over the green. + + align:start position:0% +then tip over the green. + + + align:start position:0% +then tip over the green. +>> Oh, right. + + align:start position:0% +>> Oh, right. + + + align:start position:0% +>> Oh, right. +>> You think you are? I think you are. + + align:start position:0% +>> You think you are? I think you are. + + + align:start position:0% +>> You think you are? I think you are. +>> What? Why? + + align:start position:0% +>> What? Why? + + + align:start position:0% +>> What? Why? +>> That was crazy. + + align:start position:0% +>> That was crazy. + + + align:start position:0% +>> That was crazy. +>> That was why That is why it's supposed + + align:start position:0% +>> That was why That is why it's supposed + + + align:start position:0% +>> That was why That is why it's supposed +to be a beginner puzzle. You can + + align:start position:0% +to be a beginner puzzle. You can + + + align:start position:0% +to be a beginner puzzle. You can +actually do it. You can actually do it. + + align:start position:0% +actually do it. You can actually do it. + + + align:start position:0% +actually do it. You can actually do it. +This is This is why this is puzzle one. + + align:start position:0% +This is This is why this is puzzle one. + + + align:start position:0% +This is This is why this is puzzle one. +>> Uh you don't have to fall on top of + + align:start position:0% +>> Uh you don't have to fall on top of + + + align:start position:0% +>> Uh you don't have to fall on top of +anything. + + align:start position:0% +anything. + + + align:start position:0% +anything. +>> It's bizarre. + + align:start position:0% +>> It's bizarre. + + + align:start position:0% +>> It's bizarre. +>> Yeah. Like the instinct is you know you + + align:start position:0% +>> Yeah. Like the instinct is you know you + + + align:start position:0% +>> Yeah. Like the instinct is you know you +want to build a path that you can walk + + align:start position:0% +want to build a path that you can walk + + + align:start position:0% +want to build a path that you can walk +makes no sense. + + align:start position:0% +makes no sense. + + + align:start position:0% +makes no sense. +>> Yeah. + + align:start position:0% +>> Yeah. + + + align:start position:0% +>> Yeah. +>> The guy does not make any + + align:start position:0% +>> The guy does not make any + + + align:start position:0% +>> The guy does not make any +>> but you know this is not entirely unlike + + align:start position:0% +>> but you know this is not entirely unlike + + + align:start position:0% +>> but you know this is not entirely unlike +the kind of puzzle that Scott does. I + + align:start position:0% +the kind of puzzle that Scott does. I + + + align:start position:0% +the kind of puzzle that Scott does. I +mean, sure, this is there's this one + + align:start position:0% +mean, sure, this is there's this one + + + align:start position:0% +mean, sure, this is there's this one +particular uh uh piece of plastic that + + align:start position:0% +particular uh uh piece of plastic that + + + align:start position:0% +particular uh uh piece of plastic that +uh that the game is designed to work + + align:start position:0% +uh that the game is designed to work + + + align:start position:0% +uh that the game is designed to work +with, but basically it's just, you know, + + align:start position:0% +with, but basically it's just, you know, + + + align:start position:0% +with, but basically it's just, you know, +it's like a book, right? It's like a + + align:start position:0% +it's like a book, right? It's like a + + + align:start position:0% +it's like a book, right? It's like a +book of puzzles. Um + + align:start position:0% +book of puzzles. Um + + + align:start position:0% +book of puzzles. Um +so there there are also solutions in + + align:start position:0% +so there there are also solutions in + + + align:start position:0% +so there there are also solutions in +here, but I I find the solutions harder + + align:start position:0% +here, but I I find the solutions harder + + + align:start position:0% +here, but I I find the solutions harder +to read than others. + + align:start position:0% +to read than others. + + + align:start position:0% +to read than others. +>> Pad recognition was in the book. + + align:start position:0% +>> Pad recognition was in the book. + + + align:start position:0% +>> Pad recognition was in the book. +>> Was it brand book? + + align:start position:0% +>> Was it brand book? + + + align:start position:0% +>> Was it brand book? +>> Yeah. + + align:start position:0% +>> Yeah. + + + align:start position:0% +>> Yeah. +>> Yeah. Yeah. So, actually that's um + + align:start position:0% +>> Yeah. Yeah. So, actually that's um + + + align:start position:0% +>> Yeah. Yeah. So, actually that's um +that's probably a good a good excuse to + + align:start position:0% +that's probably a good a good excuse to + + + align:start position:0% +that's probably a good a good excuse to +switch over to Brenda's. Uh well, + + align:start position:0% +switch over to Brenda's. Uh well, + + + align:start position:0% +switch over to Brenda's. Uh well, +actually before that I want to talk a + + align:start position:0% +actually before that I want to talk a + + + align:start position:0% +actually before that I want to talk a +little bit about tangs. I mean everyone + + align:start position:0% +little bit about tangs. I mean everyone + + + align:start position:0% +little bit about tangs. I mean everyone +play the tangs. + + align:start position:0% +play the tangs. + + + align:start position:0% +play the tangs. +>> No. Okay. So, you know the basic idea is + + align:start position:0% +>> No. Okay. So, you know the basic idea is + + + align:start position:0% +>> No. Okay. So, you know the basic idea is +you got these shapes. Um is this + + align:start position:0% +you got these shapes. Um is this + + + align:start position:0% +you got these shapes. Um is this +magnetic? Yeah, it is. + + align:start position:0% +magnetic? Yeah, it is. + + + align:start position:0% +magnetic? Yeah, it is. +>> Cool. Um, you've got these shapes and if + + align:start position:0% +>> Cool. Um, you've got these shapes and if + + + align:start position:0% +>> Cool. Um, you've got these shapes and if +you assemble them right, as the box, + + align:start position:0% +you assemble them right, as the box, + + + align:start position:0% +you assemble them right, as the box, +this is usually displayed on the side of + + align:start position:0% +this is usually displayed on the side of + + + align:start position:0% +this is usually displayed on the side of +a box somewhere. Where the heck are we + + align:start position:0% +a box somewhere. Where the heck are we + + + align:start position:0% +a box somewhere. Where the heck are we +on the inside? + + align:start position:0% +on the inside? + + + align:start position:0% +on the inside? +>> I I've got a big P picture on the side + + align:start position:0% +>> I I've got a big P picture on the side + + + align:start position:0% +>> I I've got a big P picture on the side +is that um you can actually fit all of + + align:start position:0% +is that um you can actually fit all of + + + align:start position:0% +is that um you can actually fit all of +these uh shapes inside that square. So, + + align:start position:0% +these uh shapes inside that square. So, + + + align:start position:0% +these uh shapes inside that square. So, +these are basically just a square that's + + align:start position:0% +these are basically just a square that's + + + align:start position:0% +these are basically just a square that's +been divided in in in a specific way. + + align:start position:0% +been divided in in in a specific way. + + + align:start position:0% +been divided in in in a specific way. +So + + align:start position:0% +So + + + align:start position:0% +So +once I got this assembled, everyone can + + align:start position:0% +once I got this assembled, everyone can + + + align:start position:0% +once I got this assembled, everyone can +just like pass this around. Anyone who's + + align:start position:0% +just like pass this around. Anyone who's + + + align:start position:0% +just like pass this around. Anyone who's +already seen it can pass it on. That one + + align:start position:0% +already seen it can pass it on. That one + + + align:start position:0% +already seen it can pass it on. That one +doesn't fit very well, but I think it's + + align:start position:0% +doesn't fit very well, but I think it's + + + align:start position:0% +doesn't fit very well, but I think it's +cool now. Hey, that's tada. Hey, so this + + align:start position:0% +cool now. Hey, that's tada. Hey, so this + + + align:start position:0% +cool now. Hey, that's tada. Hey, so this +is the basic set. This is No. + + align:start position:0% +is the basic set. This is No. + + + align:start position:0% +is the basic set. This is No. +Um, this is now this is how it's been + + align:start position:0% +Um, this is now this is how it's been + + + align:start position:0% +Um, this is now this is how it's been +sold at least is that this is actually a + + align:start position:0% +sold at least is that this is actually a + + + align:start position:0% +sold at least is that this is actually a +calendar. So every day you get a + + align:start position:0% +calendar. So every day you get a + + + align:start position:0% +calendar. So every day you get a +different shape. + + align:start position:0% +different shape. + + + align:start position:0% +different shape. +>> It's a cute little thing. You know, some + + align:start position:0% +>> It's a cute little thing. You know, some + + + align:start position:0% +>> It's a cute little thing. You know, some +of them have pretty rudimentary like + + align:start position:0% +of them have pretty rudimentary like + + + align:start position:0% +of them have pretty rudimentary like +geometric shape. Some of them have like + + align:start position:0% +geometric shape. Some of them have like + + + align:start position:0% +geometric shape. Some of them have like +I think this is supposed to be a sphinx + + align:start position:0% +I think this is supposed to be a sphinx + + + align:start position:0% +I think this is supposed to be a sphinx +or some kind. Yeah, it looks like a + + align:start position:0% +or some kind. Yeah, it looks like a + + + align:start position:0% +or some kind. Yeah, it looks like a +frog. + + align:start position:0% +frog. + + + align:start position:0% +frog. +>> But this looks like a Pac-Man. + + align:start position:0% + + + + align:start position:0% + +Um + + align:start position:0% +Um + + + align:start position:0% +Um +you know and you know + + align:start position:0% + + + + align:start position:0% + +um so the idea is that uh you know you + + align:start position:0% +um so the idea is that uh you know you + + + align:start position:0% +um so the idea is that uh you know you +rearrange those particular shapes into + + align:start position:0% +rearrange those particular shapes into + + + align:start position:0% +rearrange those particular shapes into +all of these different shapes and uh you + + align:start position:0% +all of these different shapes and uh you + + + align:start position:0% +all of these different shapes and uh you +know it's it's you could play the game + + align:start position:0% +know it's it's you could play the game + + + align:start position:0% +know it's it's you could play the game +without getting these puzzle solutions, + + align:start position:0% +without getting these puzzle solutions, + + + align:start position:0% +without getting these puzzle solutions, +right? And Scott Ken talks about a lot + + align:start position:0% +right? And Scott Ken talks about a lot + + + align:start position:0% +right? And Scott Ken talks about a lot +about like first if you've got a toy + + align:start position:0% +about like first if you've got a toy + + + align:start position:0% +about like first if you've got a toy +that's worth playing with, now you've + + align:start position:0% +that's worth playing with, now you've + + + align:start position:0% +that's worth playing with, now you've +got the beginning of something that + + align:start position:0% +got the beginning of something that + + + align:start position:0% +got the beginning of something that +would be a good thing. The nice thing + + align:start position:0% +would be a good thing. The nice thing + + + align:start position:0% +would be a good thing. The nice thing +about tipover is that it's kind of fun + + align:start position:0% +about tipover is that it's kind of fun + + + align:start position:0% +about tipover is that it's kind of fun +to tip over things. + + align:start position:0% +to tip over things. + + + align:start position:0% +to tip over things. +And the thing about tangs is that I + + align:start position:0% +And the thing about tangs is that I + + + align:start position:0% +And the thing about tangs is that I +actually had more fun playing with tangs + + align:start position:0% +actually had more fun playing with tangs + + + align:start position:0% +actually had more fun playing with tangs +than trying to solve specific problem + + align:start position:0% +than trying to solve specific problem + + + align:start position:0% +than trying to solve specific problem +just like just trying to rearrange + + align:start position:0% +just like just trying to rearrange + + + align:start position:0% +just like just trying to rearrange +these. Who hasn't seen these before? + + align:start position:0% +these. Who hasn't seen these before? + + + align:start position:0% +these. Who hasn't seen these before? +Get a sense of + + align:start position:0% +Get a sense of + + + align:start position:0% +Get a sense of +>> wow. + + align:start position:0% + + + + align:start position:0% + +be ashamed to yourself + + align:start position:0% +be ashamed to yourself + + + align:start position:0% +be ashamed to yourself +and uh + + align:start position:0% +and uh + + + align:start position:0% +and uh +>> and all the work that you did is gone. + + align:start position:0% + + + + align:start position:0% + +>> But that's the thing is that you know as + + align:start position:0% +>> But that's the thing is that you know as + + + align:start position:0% +>> But that's the thing is that you know as +a toy you know it doesn't really matter + + align:start position:0% +a toy you know it doesn't really matter + + + align:start position:0% +a toy you know it doesn't really matter +right because it's just it's just a it's + + align:start position:0% +right because it's just it's just a it's + + + align:start position:0% +right because it's just it's just a it's +just a piece a set of pieces that can be + + align:start position:0% +just a piece a set of pieces that can be + + + align:start position:0% +just a piece a set of pieces that can be +configuring anything and you kind of + + align:start position:0% +configuring anything and you kind of + + + align:start position:0% +configuring anything and you kind of +want to take it apart and you know make + + align:start position:0% +want to take it apart and you know make + + + align:start position:0% +want to take it apart and you know make +new shapes with it like little house. + + align:start position:0% +new shapes with it like little house. + + + align:start position:0% +new shapes with it like little house. +Um, + + align:start position:0% +Um, + + + align:start position:0% +Um, +so you know, if you've got something + + align:start position:0% +so you know, if you've got something + + + align:start position:0% +so you know, if you've got something +that's kind of fun to fiddle with to + + align:start position:0% +that's kind of fun to fiddle with to + + + align:start position:0% +that's kind of fun to fiddle with to +begin with, you've got possibly the + + align:start position:0% +begin with, you've got possibly the + + + align:start position:0% +begin with, you've got possibly the +beginning of a game in general, uh, but, + + align:start position:0% +beginning of a game in general, uh, but, + + + align:start position:0% +beginning of a game in general, uh, but, +uh, the way how Scott was talking about + + align:start position:0% +uh, the way how Scott was talking about + + + align:start position:0% +uh, the way how Scott was talking about +it, there's this intermediate step where + + align:start position:0% +it, there's this intermediate step where + + + align:start position:0% +it, there's this intermediate step where +it's a puzzle, you know, it's this it's + + align:start position:0% +it's a puzzle, you know, it's this it's + + + align:start position:0% +it's a puzzle, you know, it's this it's +a toy with a specific solution that + + align:start position:0% +a toy with a specific solution that + + + align:start position:0% +a toy with a specific solution that +you're trying to get to. And then gaming + + align:start position:0% +you're trying to get to. And then gaming + + + align:start position:0% +you're trying to get to. And then gaming +is kind of like one step beyond that + + align:start position:0% +is kind of like one step beyond that + + + align:start position:0% +is kind of like one step beyond that +where now there's like multiple + + align:start position:0% +where now there's like multiple + + + align:start position:0% +where now there's like multiple +solutions and competitive uh at least + + align:start position:0% +solutions and competitive uh at least + + + align:start position:0% +solutions and competitive uh at least +that's that's how he was constructing + + align:start position:0% +that's that's how he was constructing + + + align:start position:0% +that's that's how he was constructing +it. He's not really a game theorist. He + + align:start position:0% +it. He's not really a game theorist. He + + + align:start position:0% +it. He's not really a game theorist. He +just puzzles. + + align:start position:0% +just puzzles. + + + align:start position:0% +just puzzles. +>> He talks about in terms of a goal, + + align:start position:0% +>> He talks about in terms of a goal, + + + align:start position:0% +>> He talks about in terms of a goal, +right? So that with a toy that you don't + + align:start position:0% +right? So that with a toy that you don't + + + align:start position:0% +right? So that with a toy that you don't +have a goal but then with a puzzle you + + align:start position:0% +have a goal but then with a puzzle you + + + align:start position:0% +have a goal but then with a puzzle you +have + + align:start position:0% +have + + + align:start position:0% +have +>> you have you have one goal with no + + align:start position:0% +>> you have you have one goal with no + + + align:start position:0% +>> you have you have one goal with no +interaction and then a game is many with + + align:start position:0% +interaction and then a game is many with + + + align:start position:0% +interaction and then a game is many with +interaction + + align:start position:0% +interaction + + + align:start position:0% +interaction +>> and possibly multiple goals as well. I + + align:start position:0% +>> and possibly multiple goals as well. I + + + align:start position:0% +>> and possibly multiple goals as well. I +don't know but but again it becomes more + + align:start position:0% +don't know but but again it becomes more + + + align:start position:0% +don't know but but again it becomes more +and more directed whereas toy is very + + align:start position:0% +and more directed whereas toy is very + + + align:start position:0% +and more directed whereas toy is very +free form. So, so there are people who + + align:start position:0% +free form. So, so there are people who + + + align:start position:0% +free form. So, so there are people who +describe games uh like the Sims for + + align:start position:0% +describe games uh like the Sims for + + + align:start position:0% +describe games uh like the Sims for +instance as actually toys, you know, and + + align:start position:0% +instance as actually toys, you know, and + + + align:start position:0% +instance as actually toys, you know, and +in the same way that you describe a + + align:start position:0% +in the same way that you describe a + + + align:start position:0% +in the same way that you describe a +dollhouse as a toy, the Sims is kind of + + align:start position:0% +dollhouse as a toy, the Sims is kind of + + + align:start position:0% +dollhouse as a toy, the Sims is kind of +like the digital uh digital dollhouse. + + align:start position:0% +like the digital uh digital dollhouse. + + + align:start position:0% +like the digital uh digital dollhouse. +But later versions of the Sims kind of + + align:start position:0% +But later versions of the Sims kind of + + + align:start position:0% +But later versions of the Sims kind of +like added more and more specific roles + + align:start position:0% +like added more and more specific roles + + + align:start position:0% +like added more and more specific roles +like you know and now you have to throw + + align:start position:0% +like you know and now you have to throw + + + align:start position:0% +like you know and now you have to throw +a party with at least five people in it + + align:start position:0% +a party with at least five people in it + + + align:start position:0% +a party with at least five people in it +uh or you have to attain career level + + align:start position:0% +uh or you have to attain career level + + + align:start position:0% +uh or you have to attain career level +you know five or something like that. Um + + align:start position:0% +you know five or something like that. Um + + + align:start position:0% +you know five or something like that. Um +I can't remember exactly how you how you + + align:start position:0% +I can't remember exactly how you how you + + + align:start position:0% +I can't remember exactly how you how you +mentioned it but then that kind of like + + align:start position:0% +mentioned it but then that kind of like + + + align:start position:0% +mentioned it but then that kind of like +has that whole we are going to give more + + align:start position:0% +has that whole we are going to give more + + + align:start position:0% +has that whole we are going to give more +and more specific things for you to work + + align:start position:0% +and more specific things for you to work + + + align:start position:0% +and more specific things for you to work +towards but it but the Sims is very + + align:start position:0% +towards but it but the Sims is very + + + align:start position:0% +towards but it but the Sims is very +careful not to lose its toy sense the + + align:start position:0% +careful not to lose its toy sense the + + + align:start position:0% +careful not to lose its toy sense the +sense of you can if you really wanted to + + align:start position:0% +sense of you can if you really wanted to + + + align:start position:0% +sense of you can if you really wanted to +just dig around with these guys just go + + align:start position:0% +just dig around with these guys just go + + + align:start position:0% +just dig around with these guys just go +right ahead just just just uh just uh uh + + align:start position:0% +right ahead just just just uh just uh uh + + + align:start position:0% +right ahead just just just uh just uh uh +just play around with them and see what + + align:start position:0% +just play around with them and see what + + + align:start position:0% +just play around with them and see what +happens. Um, so yeah. + + align:start position:0% +happens. Um, so yeah. + + + align:start position:0% +happens. Um, so yeah. +>> Why is there a distinction for physical + + align:start position:0% +>> Why is there a distinction for physical + + + align:start position:0% +>> Why is there a distinction for physical +objects between toys and games? But for + + align:start position:0% +objects between toys and games? But for + + + align:start position:0% +objects between toys and games? But for +like video games like Minecraft is + + align:start position:0% +like video games like Minecraft is + + + align:start position:0% +like video games like Minecraft is +technically still a game, but it's + + align:start position:0% +technically still a game, but it's + + + align:start position:0% +technically still a game, but it's +different modes. Yeah, + + align:start position:0% +different modes. Yeah, + + + align:start position:0% +different modes. Yeah, +>> I guess it has different modes, but it's + + align:start position:0% +>> I guess it has different modes, but it's + + + align:start position:0% +>> I guess it has different modes, but it's +more of a toy. I think + + align:start position:0% +more of a toy. I think + + + align:start position:0% +more of a toy. I think +>> I would say that that's entirely + + align:start position:0% +>> I would say that that's entirely + + + align:start position:0% +>> I would say that that's entirely +marketing. That's the only reason is um + + align:start position:0% +marketing. That's the only reason is um + + + align:start position:0% +marketing. That's the only reason is um +people haven't figured out how to sell + + align:start position:0% +people haven't figured out how to sell + + + align:start position:0% +people haven't figured out how to sell +digital toys and there are games idolis + + align:start position:0% +digital toys and there are games idolis + + + align:start position:0% +digital toys and there are games idolis +in like Best Buy and and so well there's + + align:start position:0% +in like Best Buy and and so well there's + + + align:start position:0% +in like Best Buy and and so well there's +this fun thing I'm going to put in the + + align:start position:0% +this fun thing I'm going to put in the + + + align:start position:0% +this fun thing I'm going to put in the +game section. Everyone starts calling it + + align:start position:0% +game section. Everyone starts calling it + + + align:start position:0% +game section. Everyone starts calling it +games and that's kind of the same the + + align:start position:0% +games and that's kind of the same the + + + align:start position:0% +games and that's kind of the same the +same thing with the Sims is like really + + align:start position:0% +same thing with the Sims is like really + + + align:start position:0% +same thing with the Sims is like really +the Sims should be its own genre but you + + align:start position:0% +the Sims should be its own genre but you + + + align:start position:0% +the Sims should be its own genre but you +can't sell its own genre that well. So + + align:start position:0% + + + + align:start position:0% + +was there a hand over here? + + align:start position:0% +was there a hand over here? + + + align:start position:0% +was there a hand over here? +Um, + + align:start position:0% +Um, + + + align:start position:0% +Um, +okay. So, so that's um that's some of + + align:start position:0% +okay. So, so that's um that's some of + + + align:start position:0% +okay. So, so that's um that's some of +the stuff with Brenda's uh uh with it + + align:start position:0% +the stuff with Brenda's uh uh with it + + + align:start position:0% +the stuff with Brenda's uh uh with it +starts reading. First, let's move on to + + align:start position:0% +starts reading. First, let's move on to + + + align:start position:0% +starts reading. First, let's move on to +Brenda's. Um, and she's very specific + + align:start position:0% +Brenda's. Um, and she's very specific + + + align:start position:0% +Brenda's. Um, and she's very specific +about the kinds of puzzles that she's + + align:start position:0% +about the kinds of puzzles that she's + + + align:start position:0% +about the kinds of puzzles that she's +talking about. There's these things that + + align:start position:0% +talking about. There's these things that + + + align:start position:0% +talking about. There's these things that +get in the way of a very specific + + align:start position:0% +get in the way of a very specific + + + align:start position:0% +get in the way of a very specific +narrative experience that a game wants + + align:start position:0% +narrative experience that a game wants + + + align:start position:0% +narrative experience that a game wants +to you to to guide you through. She she + + align:start position:0% +to you to to guide you through. She she + + + align:start position:0% +to you to to guide you through. She she +describes them more as roadblocks than + + align:start position:0% +describes them more as roadblocks than + + + align:start position:0% +describes them more as roadblocks than +anything else. um but you know things to + + align:start position:0% +anything else. um but you know things to + + + align:start position:0% +anything else. um but you know things to +sort of like make the challenge higher + + align:start position:0% +sort of like make the challenge higher + + + align:start position:0% +sort of like make the challenge higher +but possibly so high that no one's going + + align:start position:0% +but possibly so high that no one's going + + + align:start position:0% +but possibly so high that no one's going +to be able to get past it. Um, some of + + align:start position:0% +to be able to get past it. Um, some of + + + align:start position:0% +to be able to get past it. Um, some of +her examples are things that come up as + + align:start position:0% +her examples are things that come up as + + + align:start position:0% +her examples are things that come up as +sort of intermittent but optional + + align:start position:0% +sort of intermittent but optional + + + align:start position:0% +sort of intermittent but optional +mechanics like hacking in bio in in in + + align:start position:0% +mechanics like hacking in bio in in in + + + align:start position:0% +mechanics like hacking in bio in in in +Bioshock. And sometimes there are like + + align:start position:0% +Bioshock. And sometimes there are like + + + align:start position:0% +Bioshock. And sometimes there are like +things that you have to solve. Uh, + + align:start position:0% +things that you have to solve. Uh, + + + align:start position:0% +things that you have to solve. Uh, +especially in adventure games, there's + + align:start position:0% +especially in adventure games, there's + + + align:start position:0% +especially in adventure games, there's +this you have to combine this object + + align:start position:0% +this you have to combine this object + + + align:start position:0% +this you have to combine this object +with that object and bring it to a + + align:start position:0% +with that object and bring it to a + + + align:start position:0% +with that object and bring it to a +specific location and then now you have + + align:start position:0% +specific location and then now you have + + + align:start position:0% +specific location and then now you have +to, you know, uh, and now you you you + + align:start position:0% +to, you know, uh, and now you you you + + + align:start position:0% +to, you know, uh, and now you you you +can proceed with whatever narrative + + align:start position:0% +can proceed with whatever narrative + + + align:start position:0% +can proceed with whatever narrative +you've got. She had this spec this + + align:start position:0% +you've got. She had this spec this + + + align:start position:0% +you've got. She had this spec this +specific axe to grind against. + + align:start position:0% +specific axe to grind against. + + + align:start position:0% +specific axe to grind against. +puzzles having meaningful rewards or not + + align:start position:0% +puzzles having meaningful rewards or not + + + align:start position:0% +puzzles having meaningful rewards or not +being completely blocking. So for + + align:start position:0% +being completely blocking. So for + + + align:start position:0% +being completely blocking. So for +instance, she says you should never have + + align:start position:0% +instance, she says you should never have + + + align:start position:0% +instance, she says you should never have +a a puzzle being required to open a + + align:start position:0% +a a puzzle being required to open a + + + align:start position:0% +a a puzzle being required to open a +door. She said solve a puzzle and then + + align:start position:0% +door. She said solve a puzzle and then + + + align:start position:0% +door. She said solve a puzzle and then +get some kind of tangible reward like or + + align:start position:0% +get some kind of tangible reward like or + + + align:start position:0% +get some kind of tangible reward like or +something. This is after I spent like + + align:start position:0% +something. This is after I spent like + + + align:start position:0% +something. This is after I spent like +the bus ride to New York City playing + + align:start position:0% +the bus ride to New York City playing + + + align:start position:0% +the bus ride to New York City playing +Professor Leon + + align:start position:0% + + + + align:start position:0% + +which was like nonstop. We found a door. + + align:start position:0% +which was like nonstop. We found a door. + + + align:start position:0% +which was like nonstop. We found a door. +It's got a lock on it. looks like a + + align:start position:0% +It's got a lock on it. looks like a + + + align:start position:0% +It's got a lock on it. looks like a +puzzle. + + align:start position:0% + + + + align:start position:0% + +So, I wasn't entirely sure what to make + + align:start position:0% +So, I wasn't entirely sure what to make + + + align:start position:0% +So, I wasn't entirely sure what to make +of that. I thought that like my + + align:start position:0% +of that. I thought that like my + + + align:start position:0% +of that. I thought that like my +professor Leighton experience was fine + + align:start position:0% +professor Leighton experience was fine + + + align:start position:0% +professor Leighton experience was fine +and I didn't need to get fat laton loot + + align:start position:0% +and I didn't need to get fat laton loot + + + align:start position:0% +and I didn't need to get fat laton loot +from + + align:start position:0% +from + + + align:start position:0% +from +>> that's that's actually something. Yeah. + + align:start position:0% +>> that's that's actually something. Yeah. + + + align:start position:0% +>> that's that's actually something. Yeah. +And and uh there's a really good article + + align:start position:0% +And and uh there's a really good article + + + align:start position:0% +And and uh there's a really good article +actually written by Clara over in our + + align:start position:0% +actually written by Clara over in our + + + align:start position:0% +actually written by Clara over in our +lab that actually was an article. It was + + align:start position:0% +lab that actually was an article. It was + + + align:start position:0% +lab that actually was an article. It was +a it was a transcript of the talk that + + align:start position:0% +a it was a transcript of the talk that + + + align:start position:0% +a it was a transcript of the talk that +she gave at Austin GDC. I I'll send out + + align:start position:0% +she gave at Austin GDC. I I'll send out + + + align:start position:0% +she gave at Austin GDC. I I'll send out +the link to everyone about how you can + + align:start position:0% +the link to everyone about how you can + + + align:start position:0% +the link to everyone about how you can +integrate and why you should integrate + + align:start position:0% +integrate and why you should integrate + + + align:start position:0% +integrate and why you should integrate +puzzles really really well in the + + align:start position:0% +puzzles really really well in the + + + align:start position:0% +puzzles really really well in the +narrative. It's like really why is there + + align:start position:0% +narrative. It's like really why is there + + + align:start position:0% +narrative. It's like really why is there +a puzzle in your game at all unless it's + + align:start position:0% +a puzzle in your game at all unless it's + + + align:start position:0% +a puzzle in your game at all unless it's +been integrated into narrative. Um and + + align:start position:0% +been integrated into narrative. Um and + + + align:start position:0% +been integrated into narrative. Um and +Brenda seems to be sort of providing a + + align:start position:0% +Brenda seems to be sort of providing a + + + align:start position:0% +Brenda seems to be sort of providing a +cautionary + + align:start position:0% +cautionary + + + align:start position:0% +cautionary +uh you know tale of the but if you do it + + align:start position:0% +uh you know tale of the but if you do it + + + align:start position:0% +uh you know tale of the but if you do it +badly no one can get on with the story. + + align:start position:0% +badly no one can get on with the story. + + + align:start position:0% +badly no one can get on with the story. +No one can enjoy the rest of the game. + + align:start position:0% +No one can enjoy the rest of the game. + + + align:start position:0% +No one can enjoy the rest of the game. +Becomes this one thing that prevents you + + align:start position:0% +Becomes this one thing that prevents you + + + align:start position:0% +Becomes this one thing that prevents you +from proceeding. Is there anyone who + + align:start position:0% +from proceeding. Is there anyone who + + + align:start position:0% +from proceeding. Is there anyone who +kind of had that moment and then + + align:start position:0% +kind of had that moment and then + + + align:start position:0% +kind of had that moment and then +>> about 5 minutes into mist + + align:start position:0% + + + + align:start position:0% + +>> I think three + + align:start position:0% +>> I think three + + + align:start position:0% +>> I think three +>> I don't know they had sort of some cool + + align:start position:0% +>> I don't know they had sort of some cool + + + align:start position:0% +>> I don't know they had sort of some cool +like live action video and stuff and it + + align:start position:0% +like live action video and stuff and it + + + align:start position:0% +like live action video and stuff and it +looked like it could be like an + + align:start position:0% +looked like it could be like an + + + align:start position:0% +looked like it could be like an +interesting story and I was kind of + + align:start position:0% +interesting story and I was kind of + + + align:start position:0% +interesting story and I was kind of +amused by the technological prowess of + + align:start position:0% +amused by the technological prowess of + + + align:start position:0% +amused by the technological prowess of +integrating like video into 3D and then + + align:start position:0% +integrating like video into 3D and then + + + align:start position:0% +integrating like video into 3D and then +suddenly I like looked into the picture + + align:start position:0% +suddenly I like looked into the picture + + + align:start position:0% +suddenly I like looked into the picture +and I was on an island and and then + + align:start position:0% +and I was on an island and and then + + + align:start position:0% +and I was on an island and and then +there was nothing happening and I had to + + align:start position:0% +there was nothing happening and I had to + + + align:start position:0% +there was nothing happening and I had to +turn things to face each other and I + + align:start position:0% +turn things to face each other and I + + + align:start position:0% +turn things to face each other and I +couldn't figure it out. + + align:start position:0% +couldn't figure it out. + + + align:start position:0% +couldn't figure it out. +>> I definitely had that when I originally + + align:start position:0% +>> I definitely had that when I originally + + + align:start position:0% +>> I definitely had that when I originally +played The Legend of Zelda the original + + align:start position:0% +played The Legend of Zelda the original + + + align:start position:0% +played The Legend of Zelda the original +one where so I don't know if you don't + + align:start position:0% +one where so I don't know if you don't + + + align:start position:0% +one where so I don't know if you don't +so they didn't tell you anything pretty + + align:start position:0% +so they didn't tell you anything pretty + + + align:start position:0% +so they didn't tell you anything pretty +much. And so the temples you have, you + + align:start position:0% +much. And so the temples you have, you + + + align:start position:0% +much. And so the temples you have, you +just walk around. There's something + + align:start position:0% +just walk around. There's something + + + align:start position:0% +just walk around. There's something +that's like, okay, there's a tree in a + + align:start position:0% +that's like, okay, there's a tree in a + + + align:start position:0% +that's like, okay, there's a tree in a +forest. You're supposed to cut, you're + + align:start position:0% +forest. You're supposed to cut, you're + + + align:start position:0% +forest. You're supposed to cut, you're +supposed to burn this particular one. + + align:start position:0% +supposed to burn this particular one. + + + align:start position:0% +supposed to burn this particular one. +And and there's the entrance to the to + + align:start position:0% +And and there's the entrance to the to + + + align:start position:0% +And and there's the entrance to the to +this temple that you can't perceive + + align:start position:0% +this temple that you can't perceive + + + align:start position:0% +this temple that you can't perceive +until you do this thing. And so it's + + align:start position:0% +until you do this thing. And so it's + + + align:start position:0% +until you do this thing. And so it's +just like, how am I supposed to know + + align:start position:0% +just like, how am I supposed to know + + + align:start position:0% +just like, how am I supposed to know +that I'm supposed to burn this + + align:start position:0% +that I'm supposed to burn this + + + align:start position:0% +that I'm supposed to burn this +particular tree in the middle of this + + align:start position:0% +particular tree in the middle of this + + + align:start position:0% +particular tree in the middle of this +huge map? + + align:start position:0% +huge map? + + + align:start position:0% +huge map? +>> Did you beat any of the other + + align:start position:0% +>> Did you beat any of the other + + + align:start position:0% +>> Did you beat any of the other +>> Yeah. And they didn't say anything. No, + + align:start position:0% +>> Yeah. And they didn't say anything. No, + + + align:start position:0% +>> Yeah. And they didn't say anything. No, +I mean the others. + + align:start position:0% +I mean the others. + + + align:start position:0% +I mean the others. +>> Yeah. + + align:start position:0% +>> Yeah. + + + align:start position:0% +>> Yeah. +>> Yeah. + + align:start position:0% +>> Yeah. + + + align:start position:0% +>> Yeah. +>> Actually, yesterday we are time again. + + align:start position:0% +>> Actually, yesterday we are time again. + + + align:start position:0% +>> Actually, yesterday we are time again. +So, + + align:start position:0% +So, + + + align:start position:0% +So, +>> I mean that tells you + + align:start position:0% +>> I mean that tells you + + + align:start position:0% +>> I mean that tells you +>> I was just saying so the interesting + + align:start position:0% +>> I was just saying so the interesting + + + align:start position:0% +>> I was just saying so the interesting +thing is so most people nowadays they + + align:start position:0% +thing is so most people nowadays they + + + align:start position:0% +thing is so most people nowadays they +end up playing like the Ocarina of Time + + align:start position:0% +end up playing like the Ocarina of Time + + + align:start position:0% +end up playing like the Ocarina of Time +and George Mass and start moving + + align:start position:0% +and George Mass and start moving + + + align:start position:0% +and George Mass and start moving +backwards. So then end up playing Zelda + + align:start position:0% +backwards. So then end up playing Zelda + + + align:start position:0% +backwards. So then end up playing Zelda +the first Zelda after having played + + align:start position:0% +the first Zelda after having played + + + align:start position:0% +the first Zelda after having played +these old ones. + + align:start position:0% +these old ones. + + + align:start position:0% +these old ones. +>> So you sort of know that you're expected + + align:start position:0% +>> So you sort of know that you're expected + + + align:start position:0% +>> So you sort of know that you're expected +to do these random things to get like + + align:start position:0% +to do these random things to get like + + + align:start position:0% +to do these random things to get like +across. So I feel like it's easier for + + align:start position:0% +across. So I feel like it's easier for + + + align:start position:0% +across. So I feel like it's easier for +people. But then, + + align:start position:0% +people. But then, + + + align:start position:0% +people. But then, +>> but with the original Zelda, the you + + align:start position:0% +>> but with the original Zelda, the you + + + align:start position:0% +>> but with the original Zelda, the you +know how in new ones they have like it's + + align:start position:0% +know how in new ones they have like it's + + + align:start position:0% +know how in new ones they have like it's +like let's say a wall you can blow up. + + align:start position:0% +like let's say a wall you can blow up. + + + align:start position:0% +like let's say a wall you can blow up. +It's discolored or something. And the in + + align:start position:0% +It's discolored or something. And the in + + + align:start position:0% +It's discolored or something. And the in +this one + + align:start position:0% +this one + + + align:start position:0% +this one +>> every tree looks exactly the same. They + + align:start position:0% +>> every tree looks exactly the same. They + + + align:start position:0% +>> every tree looks exactly the same. They +use the same sprites. + + align:start position:0% +use the same sprites. + + + align:start position:0% +use the same sprites. +>> If I remember correctly though, it's + + align:start position:0% +>> If I remember correctly though, it's + + + align:start position:0% +>> If I remember correctly though, it's +placed such that it's like in the center + + align:start position:0% +placed such that it's like in the center + + + align:start position:0% +placed such that it's like in the center +of your screen, right? So it does look a + + align:start position:0% +of your screen, right? So it does look a + + + align:start position:0% +of your screen, right? So it does look a +little bit different. + + align:start position:0% +little bit different. + + + align:start position:0% +little bit different. +>> No, no, + + align:start position:0% +>> No, no, + + + align:start position:0% +>> No, no, +>> it was like + + align:start position:0% +>> it was like + + + align:start position:0% +>> it was like +>> it was just a random tree. + + align:start position:0% +>> it was just a random tree. + + + align:start position:0% +>> it was just a random tree. +>> Band of trees. + + align:start position:0% +>> Band of trees. + + + align:start position:0% +>> Band of trees. +>> Yeah, it was just a whole bunch of + + align:start position:0% +>> Yeah, it was just a whole bunch of + + + align:start position:0% +>> Yeah, it was just a whole bunch of +trees. + + align:start position:0% +trees. + + + align:start position:0% +trees. +And so you just you really just have to + + align:start position:0% +And so you just you really just have to + + + align:start position:0% +And so you just you really just have to +get a whatever like a type of thing to + + align:start position:0% +get a whatever like a type of thing to + + + align:start position:0% +get a whatever like a type of thing to +burn it and a specific one + + align:start position:0% +burn it and a specific one + + + align:start position:0% +burn it and a specific one +>> and burn it. Usually that place is a + + align:start position:0% +>> and burn it. Usually that place is a + + + align:start position:0% +>> and burn it. Usually that place is a +little suspicious. So I think there was + + align:start position:0% +little suspicious. So I think there was + + + align:start position:0% +little suspicious. So I think there was +like a one tile column like you could + + align:start position:0% +like a one tile column like you could + + + align:start position:0% +like a one tile column like you could +like navigate around just like this like + + align:start position:0% +like navigate around just like this like + + + align:start position:0% +like navigate around just like this like +loop you just entered and was + + align:start position:0% +loop you just entered and was + + + align:start position:0% +loop you just entered and was +suspicious. + + align:start position:0% + + + + align:start position:0% + +>> I feel very frustrated by games that + + align:start position:0% +>> I feel very frustrated by games that + + + align:start position:0% +>> I feel very frustrated by games that +like require walkthroughs in order to + + align:start position:0% +like require walkthroughs in order to + + + align:start position:0% +like require walkthroughs in order to +play them. Sure. And that was the other + + align:start position:0% +play them. Sure. And that was the other + + + align:start position:0% +play them. Sure. And that was the other +thing that she said that she suggested + + align:start position:0% +thing that she said that she suggested + + + align:start position:0% +thing that she said that she suggested +some game designers do. They put the + + align:start position:0% +some game designers do. They put the + + + align:start position:0% +some game designers do. They put the +solution in the the the Prima guide so + + align:start position:0% +solution in the the the Prima guide so + + + align:start position:0% +solution in the the the Prima guide so +that you have to buy the Prima guide in + + align:start position:0% +that you have to buy the Prima guide in + + + align:start position:0% +that you have to buy the Prima guide in +order to otherwise. + + align:start position:0% +order to otherwise. + + + align:start position:0% +order to otherwise. +>> But it's also + + align:start position:0% +>> But it's also + + + align:start position:0% +>> But it's also +deal with the + + align:start position:0% +deal with the + + + align:start position:0% +deal with the +>> Well, you must have Oh, + + align:start position:0% +>> Well, you must have Oh, + + + align:start position:0% +>> Well, you must have Oh, +>> yeah. + + align:start position:0% +>> yeah. + + + align:start position:0% +>> yeah. +>> There's actually say official on the top + + align:start position:0% +>> There's actually say official on the top + + + align:start position:0% +>> There's actually say official on the top +for a reason. + + align:start position:0% +for a reason. + + + align:start position:0% +for a reason. +See, it's also ironic because modern + + align:start position:0% +See, it's also ironic because modern + + + align:start position:0% +See, it's also ironic because modern +Zelda games like they they hold it's + + align:start position:0% +Zelda games like they they hold it's + + + align:start position:0% +Zelda games like they they hold it's +very obvious that you have to use this + + align:start position:0% +very obvious that you have to use this + + + align:start position:0% +very obvious that you have to use this +or that item. + + align:start position:0% +or that item. + + + align:start position:0% +or that item. +>> You got a key. Use this key to open. + + align:start position:0% +>> You got a key. Use this key to open. + + + align:start position:0% +>> You got a key. Use this key to open. +>> Oh, you got this item in the dungeon. + + align:start position:0% +>> Oh, you got this item in the dungeon. + + + align:start position:0% +>> Oh, you got this item in the dungeon. +You had to use this item to kill the + + align:start position:0% +You had to use this item to kill the + + + align:start position:0% +You had to use this item to kill the +boss. That sort of thing. Like it's + + align:start position:0% +boss. That sort of thing. Like it's + + + align:start position:0% +boss. That sort of thing. Like it's +blatant. + + align:start position:0% +blatant. + + + align:start position:0% +blatant. +>> Well, for people who are really really + + align:start position:0% +>> Well, for people who are really really + + + align:start position:0% +>> Well, for people who are really really +hopeless, there's the little fairy. + + align:start position:0% +hopeless, there's the little fairy. + + + align:start position:0% +hopeless, there's the little fairy. +>> Hey, listen. Listen. is usually less + + align:start position:0% +>> Hey, listen. Listen. is usually less + + + align:start position:0% +>> Hey, listen. Listen. is usually less +less useful than + + align:start position:0% +less useful than + + + align:start position:0% +less useful than +>> but I mean I mean so one big difference + + align:start position:0% +>> but I mean I mean so one big difference + + + align:start position:0% +>> but I mean I mean so one big difference +between the old Zelda games and the new + + align:start position:0% +between the old Zelda games and the new + + + align:start position:0% +between the old Zelda games and the new +Zelda games it's just this continual + + align:start position:0% +Zelda games it's just this continual + + + align:start position:0% +Zelda games it's just this continual +refinement in the user interface um and + + align:start position:0% +refinement in the user interface um and + + + align:start position:0% +refinement in the user interface um and +you know in it goes all the way from + + align:start position:0% +you know in it goes all the way from + + + align:start position:0% +you know in it goes all the way from +like little things like um like the like + + align:start position:0% +like little things like um like the like + + + align:start position:0% +like little things like um like the like +the notes that you hear when you find a + + align:start position:0% +the notes that you hear when you find a + + + align:start position:0% +the notes that you hear when you find a +new dungeon you know and when you hear + + align:start position:0% +new dungeon you know and when you hear + + + align:start position:0% +new dungeon you know and when you hear +exactly when precisely you hear the + + align:start position:0% +exactly when precisely you hear the + + + align:start position:0% +exactly when precisely you hear the +sound of you know + + align:start position:0% +sound of you know + + + align:start position:0% +sound of you know +if I think + + align:start position:0% +if I think + + + align:start position:0% +if I think +um you know as a clue that now you have + + align:start position:0% +um you know as a clue that now you have + + + align:start position:0% +um you know as a clue that now you have +opened a door um that that that's one of + + align:start position:0% +opened a door um that that that's one of + + + align:start position:0% +opened a door um that that that's one of +those things that if you if you look at + + align:start position:0% +those things that if you if you look at + + + align:start position:0% +those things that if you if you look at +postmodms of ocarina time I think + + align:start position:0% +postmodms of ocarina time I think + + + align:start position:0% +postmodms of ocarina time I think +there's a couple on gamma sudra exactly + + align:start position:0% +there's a couple on gamma sudra exactly + + + align:start position:0% +there's a couple on gamma sudra exactly +when that sound plays is a decision that + + align:start position:0% +when that sound plays is a decision that + + + align:start position:0% +when that sound plays is a decision that +was very carefully designed um and uh it + + align:start position:0% +was very carefully designed um and uh it + + + align:start position:0% +was very carefully designed um and uh it +seems to me that in digital puzzles in + + align:start position:0% +seems to me that in digital puzzles in + + + align:start position:0% +seems to me that in digital puzzles in +those kinds of like especially in some + + align:start position:0% +those kinds of like especially in some + + + align:start position:0% +those kinds of like especially in some +sort of narrative structure like in + + align:start position:0% +sort of narrative structure like in + + + align:start position:0% +sort of narrative structure like in +opera um that's the big problem that you + + align:start position:0% +opera um that's the big problem that you + + + align:start position:0% +opera um that's the big problem that you +have to solve you have to give enough + + align:start position:0% +have to solve you have to give enough + + + align:start position:0% +have to solve you have to give enough +clues you have to give enough UI + + align:start position:0% +clues you have to give enough UI + + + align:start position:0% +clues you have to give enough UI +feedback and you have to think about + + align:start position:0% +feedback and you have to think about + + + align:start position:0% +feedback and you have to think about +your UI so hard um in a way that is + + align:start position:0% +your UI so hard um in a way that is + + + align:start position:0% +your UI so hard um in a way that is +going to make it possible for people to + + align:start position:0% +going to make it possible for people to + + + align:start position:0% +going to make it possible for people to +get all the information they need. So + + align:start position:0% +get all the information they need. So + + + align:start position:0% +get all the information they need. So +say that burning fire tree situation if + + align:start position:0% +say that burning fire tree situation if + + + align:start position:0% +say that burning fire tree situation if +there's nowhere else in the world for + + align:start position:0% +there's nowhere else in the world for + + + align:start position:0% +there's nowhere else in the world for +you to get that information that's bad + + align:start position:0% +you to get that information that's bad + + + align:start position:0% +you to get that information that's bad +design puzzle. If there is a guy in I I + + align:start position:0% +design puzzle. If there is a guy in I I + + + align:start position:0% +design puzzle. If there is a guy in I I +can't remember the Zelda one, but if + + align:start position:0% +can't remember the Zelda one, but if + + + align:start position:0% +can't remember the Zelda one, but if +there is a guy who actually tells you + + align:start position:0% +there is a guy who actually tells you + + + align:start position:0% +there is a guy who actually tells you +that that's the tree that you need to + + align:start position:0% +that that's the tree that you need to + + + align:start position:0% +that that's the tree that you need to +burn, but it's not obvious, especially + + align:start position:0% +burn, but it's not obvious, especially + + + align:start position:0% +burn, but it's not obvious, especially +for someone who hasn't encountered that + + align:start position:0% +for someone who hasn't encountered that + + + align:start position:0% +for someone who hasn't encountered that +guy, that that's where you get the + + align:start position:0% +guy, that that's where you get the + + + align:start position:0% +guy, that that's where you get the +information. It's still a bad design + + align:start position:0% +information. It's still a bad design + + + align:start position:0% +information. It's still a bad design +puzzle, even though now that's the + + align:start position:0% +puzzle, even though now that's the + + + align:start position:0% +puzzle, even though now that's the +solution. Um but thinking about and some + + align:start position:0% +solution. Um but thinking about and some + + + align:start position:0% +solution. Um but thinking about and some +examples will be u in a lot of textbased + + align:start position:0% +examples will be u in a lot of textbased + + + align:start position:0% +examples will be u in a lot of textbased +adventures as well as graphical text + + align:start position:0% +adventures as well as graphical text + + + align:start position:0% +adventures as well as graphical text +heavy graphical adventures you have a I + + align:start position:0% +heavy graphical adventures you have a I + + + align:start position:0% +heavy graphical adventures you have a I +can't solve this puzzle but what my + + align:start position:0% +can't solve this puzzle but what my + + + align:start position:0% +can't solve this puzzle but what my +character says to the player about why + + align:start position:0% +character says to the player about why + + + align:start position:0% +character says to the player about why +you can't solve the puzzle itself a clue + + align:start position:0% +you can't solve the puzzle itself a clue + + + align:start position:0% +you can't solve the puzzle itself a clue +it's like I must not have had I I must + + align:start position:0% +it's like I must not have had I I must + + + align:start position:0% +it's like I must not have had I I must +not have the right item like you know + + align:start position:0% +not have the right item like you know + + + align:start position:0% +not have the right item like you know +maybe there's something else I can use. + + align:start position:0% +maybe there's something else I can use. + + + align:start position:0% +maybe there's something else I can use. +That's a huge clue. I feel like digital + + align:start position:0% +That's a huge clue. I feel like digital + + + align:start position:0% +That's a huge clue. I feel like digital +puzzle games have gotten really good at + + align:start position:0% +puzzle games have gotten really good at + + + align:start position:0% +puzzle games have gotten really good at +integrating hint systems + + align:start position:0% +integrating hint systems + + + align:start position:0% +integrating hint systems +um in recent years, + + align:start position:0% +um in recent years, + + + align:start position:0% +um in recent years, +but I can't think of any physical + + align:start position:0% +but I can't think of any physical + + + align:start position:0% +but I can't think of any physical +puzzles that I've come across, though I + + align:start position:0% +puzzles that I've come across, though I + + + align:start position:0% +puzzles that I've come across, though I +may just not have caught it like been up + + align:start position:0% +may just not have caught it like been up + + + align:start position:0% +may just not have caught it like been up +to speed with physical puzzles that have + + align:start position:0% +to speed with physical puzzles that have + + + align:start position:0% +to speed with physical puzzles that have +that kind of + + align:start position:0% +that kind of + + + align:start position:0% +that kind of +not totally revealing the solution, but + + align:start position:0% +not totally revealing the solution, but + + + align:start position:0% +not totally revealing the solution, but +giving you a gradual hint which can help + + align:start position:0% +giving you a gradual hint which can help + + + align:start position:0% +giving you a gradual hint which can help +you figure it out. Well, mystery hunt + + align:start position:0% +you figure it out. Well, mystery hunt + + + align:start position:0% +you figure it out. Well, mystery hunt +puzzle is kind of + + align:start position:0% +puzzle is kind of + + + align:start position:0% +puzzle is kind of +>> Oh, + + align:start position:0% +>> Oh, + + + align:start position:0% +>> Oh, +this + + align:start position:0% + + + + align:start position:0% + +describe the mystery hunt for folks who + + align:start position:0% +describe the mystery hunt for folks who + + + align:start position:0% +describe the mystery hunt for folks who +don't who + + align:start position:0% +don't who + + + align:start position:0% +don't who +>> uh it's basically it's a competition run + + align:start position:0% +>> uh it's basically it's a competition run + + + align:start position:0% +>> uh it's basically it's a competition run +at MIT over AP where uh teams of people + + align:start position:0% +at MIT over AP where uh teams of people + + + align:start position:0% +at MIT over AP where uh teams of people +compete to solve a bunch of puzzles like + + align:start position:0% +compete to solve a bunch of puzzles like + + + align:start position:0% +compete to solve a bunch of puzzles like +70 puzzles that kind of build on each + + align:start position:0% +70 puzzles that kind of build on each + + + align:start position:0% +70 puzzles that kind of build on each +other. So you have, you know, say 20 + + align:start position:0% +other. So you have, you know, say 20 + + + align:start position:0% +other. So you have, you know, say 20 +base puzzles and you solve those 20 + + align:start position:0% +base puzzles and you solve those 20 + + + align:start position:0% +base puzzles and you solve those 20 +puzzles, you get 20 words as solutions + + align:start position:0% +puzzles, you get 20 words as solutions + + + align:start position:0% +puzzles, you get 20 words as solutions +and then those 20 words become a new + + align:start position:0% +and then those 20 words become a new + + + align:start position:0% +and then those 20 words become a new +puzzle and it's a meta puzzle and it + + align:start position:0% +puzzle and it's a meta puzzle and it + + + align:start position:0% +puzzle and it's a meta puzzle and it +keep kind of keeps going like that for a + + align:start position:0% +keep kind of keeps going like that for a + + + align:start position:0% +keep kind of keeps going like that for a +couple layers. But the point is the + + align:start position:0% +couple layers. But the point is the + + + align:start position:0% +couple layers. But the point is the +winning team from the previous year + + align:start position:0% +winning team from the previous year + + + align:start position:0% +winning team from the previous year +writes the next year's mystery hunt. So + + align:start position:0% +writes the next year's mystery hunt. So + + + align:start position:0% +writes the next year's mystery hunt. So +like you get all kinds of varying + + align:start position:0% +like you get all kinds of varying + + + align:start position:0% +like you get all kinds of varying +puzzles of varying difficulties and + + align:start position:0% +puzzles of varying difficulties and + + + align:start position:0% +puzzles of varying difficulties and +styles and a very well-designed puzzle + + align:start position:0% +styles and a very well-designed puzzle + + + align:start position:0% +styles and a very well-designed puzzle +actually does that because you have this + + align:start position:0% +actually does that because you have this + + + align:start position:0% +actually does that because you have this +thing called flavor. Oh, I guess I + + align:start position:0% +thing called flavor. Oh, I guess I + + + align:start position:0% +thing called flavor. Oh, I guess I +should say that the puzzles aren't like + + align:start position:0% +should say that the puzzles aren't like + + + align:start position:0% +should say that the puzzles aren't like +sudoku or crosswords. You literally just + + align:start position:0% +sudoku or crosswords. You literally just + + + align:start position:0% +sudoku or crosswords. You literally just +get, you know, something on a screen or + + align:start position:0% +get, you know, something on a screen or + + + align:start position:0% +get, you know, something on a screen or +something on a piece of paper and you + + align:start position:0% +something on a piece of paper and you + + + align:start position:0% +something on a piece of paper and you +have to figure out what to do with it. + + align:start position:0% +have to figure out what to do with it. + + + align:start position:0% +have to figure out what to do with it. +You're not given any instructions for + + align:start position:0% +You're not given any instructions for + + + align:start position:0% +You're not given any instructions for +how to solve it whatsoever. And the the + + align:start position:0% +how to solve it whatsoever. And the the + + + align:start position:0% +how to solve it whatsoever. And the the +only clues you get are either by the + + align:start position:0% +only clues you get are either by the + + + align:start position:0% +only clues you get are either by the +title of the puzzle, by like the group + + align:start position:0% +title of the puzzle, by like the group + + + align:start position:0% +title of the puzzle, by like the group +of puzzles that it's in, or by this + + align:start position:0% +of puzzles that it's in, or by this + + + align:start position:0% +of puzzles that it's in, or by this +thing called flavor text, which is like + + align:start position:0% +thing called flavor text, which is like + + + align:start position:0% +thing called flavor text, which is like +they say some kind of random phrase that + + align:start position:0% +they say some kind of random phrase that + + + align:start position:0% +they say some kind of random phrase that +seems to not have anything to do with + + align:start position:0% +seems to not have anything to do with + + + align:start position:0% +seems to not have anything to do with +anything, but that kind of gives you a + + align:start position:0% +anything, but that kind of gives you a + + + align:start position:0% +anything, but that kind of gives you a +clue about what to do in the first + + align:start position:0% +clue about what to do in the first + + + align:start position:0% +clue about what to do in the first +puzzle. + + align:start position:0% +puzzle. + + + align:start position:0% +puzzle. +>> So that's it's kind of like what you're + + align:start position:0% +>> So that's it's kind of like what you're + + + align:start position:0% +>> So that's it's kind of like what you're +describing. That's interesting because I + + align:start position:0% +describing. That's interesting because I + + + align:start position:0% +describing. That's interesting because I +mean it's really challenging when you + + align:start position:0% +mean it's really challenging when you + + + align:start position:0% +mean it's really challenging when you +don't have any mechanism for like giving + + align:start position:0% +don't have any mechanism for like giving + + + align:start position:0% +don't have any mechanism for like giving +feedback to the person who's working on + + align:start position:0% +feedback to the person who's working on + + + align:start position:0% +feedback to the person who's working on +a puzzle. It in Zelda or what have you. + + align:start position:0% +a puzzle. It in Zelda or what have you. + + + align:start position:0% +a puzzle. It in Zelda or what have you. +You can see that they've spent a long + + align:start position:0% +You can see that they've spent a long + + + align:start position:0% +You can see that they've spent a long +time + + align:start position:0% +time + + + align:start position:0% +time + around. + + align:start position:0% + around. + + + align:start position:0% + around. +It's kind of a double-edged sword in + + align:start position:0% +It's kind of a double-edged sword in + + + align:start position:0% +It's kind of a double-edged sword in +that particular case because you had so + + align:start position:0% +that particular case because you had so + + + align:start position:0% +that particular case because you had so +many mechanisms and now you're expected + + align:start position:0% +many mechanisms and now you're expected + + + align:start position:0% +many mechanisms and now you're expected +to use all of them. Uh in in in in a + + align:start position:0% +to use all of them. Uh in in in in a + + + align:start position:0% +to use all of them. Uh in in in in a +game like like you have to use sound, + + align:start position:0% +game like like you have to use sound, + + + align:start position:0% +game like like you have to use sound, +you have to use contextual buttons, you + + align:start position:0% +you have to use contextual buttons, you + + + align:start position:0% +you have to use contextual buttons, you +have to use the inventory, uh the + + align:start position:0% +have to use the inventory, uh the + + + align:start position:0% +have to use the inventory, uh the +position of the player matters, you + + align:start position:0% +position of the player matters, you + + + align:start position:0% +position of the player matters, you +know, sometimes I've seen games where + + align:start position:0% +know, sometimes I've seen games where + + + align:start position:0% +know, sometimes I've seen games where +the the main clue is what is the the + + align:start position:0% +the the main clue is what is the the + + + align:start position:0% +the the main clue is what is the the +character looking at for instance, you + + align:start position:0% +character looking at for instance, you + + + align:start position:0% +character looking at for instance, you +know, and if you walk around, why does + + align:start position:0% +know, and if you walk around, why does + + + align:start position:0% +know, and if you walk around, why does +my character keep looking that way every + + align:start position:0% +my character keep looking that way every + + + align:start position:0% +my character keep looking that way every +time I look at it? Oh, that's the clue, + + align:start position:0% +time I look at it? Oh, that's the clue, + + + align:start position:0% +time I look at it? Oh, that's the clue, +you know. Um so so yeah for us in a lot + + align:start position:0% +you know. Um so so yeah for us in a lot + + + align:start position:0% +you know. Um so so yeah for us in a lot +of like um physical stuff um I would say + + align:start position:0% +of like um physical stuff um I would say + + + align:start position:0% +of like um physical stuff um I would say +that one of the reasons is if you're + + align:start position:0% +that one of the reasons is if you're + + + align:start position:0% +that one of the reasons is if you're +starting if you're starting to build + + align:start position:0% +starting if you're starting to build + + + align:start position:0% +starting if you're starting to build +these physical games from toys um you a + + align:start position:0% +these physical games from toys um you a + + + align:start position:0% +these physical games from toys um you a +lot of the affordances + + align:start position:0% +lot of the affordances + + + align:start position:0% +lot of the affordances +a a lot of things you could possibly do + + align:start position:0% +a a lot of things you could possibly do + + + align:start position:0% +a a lot of things you could possibly do +are kind of built into the physical + + align:start position:0% +are kind of built into the physical + + + align:start position:0% +are kind of built into the physical +object. Uh, and if you're building a + + align:start position:0% +object. Uh, and if you're building a + + + align:start position:0% +object. Uh, and if you're building a +puzzle based on what you could do as + + align:start position:0% +puzzle based on what you could do as + + + align:start position:0% +puzzle based on what you could do as +with these things as a toy, um, then + + align:start position:0% +with these things as a toy, um, then + + + align:start position:0% +with these things as a toy, um, then +you're necessarily already using the + + align:start position:0% +you're necessarily already using the + + + align:start position:0% +you're necessarily already using the +constraints of what you can do it do + + align:start position:0% +constraints of what you can do it do + + + align:start position:0% +constraints of what you can do it do +with it as a toy in order to try to to + + align:start position:0% +with it as a toy in order to try to to + + + align:start position:0% +with it as a toy in order to try to to +to create a puzzle. + + align:start position:0% +to create a puzzle. + + + align:start position:0% +to create a puzzle. +Um, + + align:start position:0% +Um, + + + align:start position:0% +Um, +this might be a good exercise actually. + + align:start position:0% +this might be a good exercise actually. + + + align:start position:0% +this might be a good exercise actually. +We have time we we we we could take a + + align:start position:0% +We have time we we we we could take a + + + align:start position:0% +We have time we we we we could take a +shot at this and just like you know + + align:start position:0% +shot at this and just like you know + + + align:start position:0% +shot at this and just like you know +trying to come up with a puzzle and see + + align:start position:0% +trying to come up with a puzzle and see + + + align:start position:0% +trying to come up with a puzzle and see +but instead of doing of imagining one in + + align:start position:0% +but instead of doing of imagining one in + + + align:start position:0% +but instead of doing of imagining one in +a digital space trying to imagine one in + + align:start position:0% +a digital space trying to imagine one in + + + align:start position:0% +a digital space trying to imagine one in +physical space and because I suspect + + align:start position:0% +physical space and because I suspect + + + align:start position:0% +physical space and because I suspect +what you actually get is that you get a + + align:start position:0% +what you actually get is that you get a + + + align:start position:0% +what you actually get is that you get a +lot of free you get a free ride with + + align:start position:0% +lot of free you get a free ride with + + + align:start position:0% +lot of free you get a free ride with +physical puzzles because things + + align:start position:0% +physical puzzles because things + + + align:start position:0% +physical puzzles because things +physically + + align:start position:0% +physically + + + align:start position:0% +physically +have interactions that puzzle + + align:start position:0% +have interactions that puzzle + + + align:start position:0% +have interactions that puzzle +I feel like uh played Portal recently + + align:start position:0% +I feel like uh played Portal recently + + + align:start position:0% +I feel like uh played Portal recently +and that's a game where like + + align:start position:0% +and that's a game where like + + + align:start position:0% +and that's a game where like +the the puzzles are it's not in a I mean + + align:start position:0% +the the puzzles are it's not in a I mean + + + align:start position:0% +the the puzzles are it's not in a I mean +obviously it's still a digital game but + + align:start position:0% +obviously it's still a digital game but + + + align:start position:0% +obviously it's still a digital game but +the puzzles are very much physical + + align:start position:0% +the puzzles are very much physical + + + align:start position:0% +the puzzles are very much physical +puzzles like you kind of have an idea + + align:start position:0% +puzzles like you kind of have an idea + + + align:start position:0% +puzzles like you kind of have an idea +about what has have people played Portal + + align:start position:0% +about what has have people played Portal + + + align:start position:0% +about what has have people played Portal +of course or know the idea + + align:start position:0% +of course or know the idea + + + align:start position:0% +of course or know the idea +okay um I mean you have these two + + align:start position:0% +okay um I mean you have these two + + + align:start position:0% +okay um I mean you have these two +portals and you like do you understand + + align:start position:0% +portals and you like do you understand + + + align:start position:0% +portals and you like do you understand +what the physics is going to be like so + + align:start position:0% +what the physics is going to be like so + + + align:start position:0% +what the physics is going to be like so +the puzzles aren't frustrating in the + + align:start position:0% +the puzzles aren't frustrating in the + + + align:start position:0% +the puzzles aren't frustrating in the +sense that it's like oh you pull you + + align:start position:0% +sense that it's like oh you pull you + + + align:start position:0% +sense that it's like oh you pull you +realize there's like this random statue + + align:start position:0% +realize there's like this random statue + + + align:start position:0% +realize there's like this random statue +here and if you like pull a lever it + + align:start position:0% +here and if you like pull a lever it + + + align:start position:0% +here and if you like pull a lever it +like raises the water level or something + + align:start position:0% +like raises the water level or something + + + align:start position:0% +like raises the water level or something +like that like it I don't know what it + + align:start position:0% +like that like it I don't know what it + + + align:start position:0% +like that like it I don't know what it +but it's like it's very intuitive and + + align:start position:0% +but it's like it's very intuitive and + + + align:start position:0% +but it's like it's very intuitive and +it's it feels like a physical puzzle in + + align:start position:0% +it's it feels like a physical puzzle in + + + align:start position:0% +it's it feels like a physical puzzle in +the sense that I know what will happen + + align:start position:0% +the sense that I know what will happen + + + align:start position:0% +the sense that I know what will happen +if I do this and I just figure out have + + align:start position:0% +if I do this and I just figure out have + + + align:start position:0% +if I do this and I just figure out have +to how to put the pieces together and + + align:start position:0% +to how to put the pieces together and + + + align:start position:0% +to how to put the pieces together and +also in portal what I think does a + + align:start position:0% +also in portal what I think does a + + + align:start position:0% +also in portal what I think does a +really good job of as well as what some + + align:start position:0% +really good job of as well as what some + + + align:start position:0% +really good job of as well as what some +physical puzzles do is having a learning + + align:start position:0% +physical puzzles do is having a learning + + + align:start position:0% +physical puzzles do is having a learning +curve like tanagram will have some basic + + align:start position:0% +curve like tanagram will have some basic + + + align:start position:0% +curve like tanagram will have some basic +puzzles or I'm sure the following thing + + align:start position:0% +puzzles or I'm sure the following thing + + + align:start position:0% +puzzles or I'm sure the following thing +a lot of them we can do physical puzzle + + align:start position:0% +a lot of them we can do physical puzzle + + + align:start position:0% +a lot of them we can do physical puzzle +things we like I don't know have to jump + + align:start position:0% +things we like I don't know have to jump + + + align:start position:0% +things we like I don't know have to jump +over pieces or whatever basic levels, + + align:start position:0% +over pieces or whatever basic levels, + + + align:start position:0% +over pieces or whatever basic levels, +basic uh boards where they show you + + align:start position:0% +basic uh boards where they show you + + + align:start position:0% +basic uh boards where they show you +various techniques and you only have to + + align:start position:0% +various techniques and you only have to + + + align:start position:0% +various techniques and you only have to +figure out one technique and it's very + + align:start position:0% +figure out one technique and it's very + + + align:start position:0% +figure out one technique and it's very +obvious what you have to do and then + + align:start position:0% +obvious what you have to do and then + + + align:start position:0% +obvious what you have to do and then +later on you have to use those + + align:start position:0% +later on you have to use those + + + align:start position:0% +later on you have to use those +techniques. + + align:start position:0% +techniques. + + + align:start position:0% +techniques. +>> Well, I mean in zippover this particular + + align:start position:0% +>> Well, I mean in zippover this particular + + + align:start position:0% +>> Well, I mean in zippover this particular +example does something that portal also + + align:start position:0% +example does something that portal also + + + align:start position:0% +example does something that portal also +does really well is that the very first + + align:start position:0% +does really well is that the very first + + + align:start position:0% +does really well is that the very first +puzzle that we did earlier only has one + + align:start position:0% +puzzle that we did earlier only has one + + + align:start position:0% +puzzle that we did earlier only has one +solution and you do not you do not get + + align:start position:0% +solution and you do not you do not get + + + align:start position:0% +solution and you do not you do not get +that solution unless you understand all + + align:start position:0% +that solution unless you understand all + + + align:start position:0% +that solution unless you understand all +the mechanics. Yeah. like we like we + + align:start position:0% +the mechanics. Yeah. like we like we + + + align:start position:0% +the mechanics. Yeah. like we like we +tried to solve it a bunch of different + + align:start position:0% +tried to solve it a bunch of different + + + align:start position:0% +tried to solve it a bunch of different +times and it's like because we didn't + + align:start position:0% +times and it's like because we didn't + + + align:start position:0% +times and it's like because we didn't +quite understand the rules, we couldn't + + align:start position:0% +quite understand the rules, we couldn't + + + align:start position:0% +quite understand the rules, we couldn't +get it until we understood the mechanics + + align:start position:0% +get it until we understood the mechanics + + + align:start position:0% +get it until we understood the mechanics +of the game. Now we can sly solve it. So + + align:start position:0% +of the game. Now we can sly solve it. So + + + align:start position:0% +of the game. Now we can sly solve it. So +from level from puzzle level two + + align:start position:0% +from level from puzzle level two + + + align:start position:0% +from level from puzzle level two +onwards, we can be confident that we + + align:start position:0% +onwards, we can be confident that we + + + align:start position:0% +onwards, we can be confident that we +actually know like Portal and even + + align:start position:0% +actually know like Portal and even + + + align:start position:0% +actually know like Portal and even +actually just about any well-designed + + align:start position:0% +actually just about any well-designed + + + align:start position:0% +actually just about any well-designed +game, but I'm going to say Portal is a + + align:start position:0% +game, but I'm going to say Portal is a + + + align:start position:0% +game, but I'm going to say Portal is a +fine example. you've beaten the game, + + align:start position:0% +fine example. you've beaten the game, + + + align:start position:0% +fine example. you've beaten the game, +you can play through the game again with + + align:start position:0% +you can play through the game again with + + + align:start position:0% +you can play through the game again with +developer commentary. And you will and + + align:start position:0% +developer commentary. And you will and + + + align:start position:0% +developer commentary. And you will and +when you hear that, you will actually + + align:start position:0% +when you hear that, you will actually + + + align:start position:0% +when you hear that, you will actually +realize that um every single fairly + + align:start position:0% +realize that um every single fairly + + + align:start position:0% +realize that um every single fairly +intuitive physical thing that that that + + align:start position:0% +intuitive physical thing that that that + + + align:start position:0% +intuitive physical thing that that that +you pick up in the game had to be taught + + align:start position:0% +you pick up in the game had to be taught + + + align:start position:0% +you pick up in the game had to be taught +to you. And they've designed the level + + align:start position:0% +to you. And they've designed the level + + + align:start position:0% +to you. And they've designed the level +very clearly. So, right at the beginning + + align:start position:0% +very clearly. So, right at the beginning + + + align:start position:0% +very clearly. So, right at the beginning +of the game, if uh folks can remember, + + align:start position:0% +of the game, if uh folks can remember, + + + align:start position:0% +of the game, if uh folks can remember, +um you're trapped in a little cell, + + align:start position:0% +um you're trapped in a little cell, + + + align:start position:0% +um you're trapped in a little cell, +right? and uh the the uh GLaDOS talks to + + align:start position:0% +right? and uh the the uh GLaDOS talks to + + + align:start position:0% +right? and uh the the uh GLaDOS talks to +you and a portal opens and you can walk + + align:start position:0% +you and a portal opens and you can walk + + + align:start position:0% +you and a portal opens and you can walk +through it. What do you see out of the + + align:start position:0% +through it. What do you see out of the + + + align:start position:0% +through it. What do you see out of the +first portal that opens? + + align:start position:0% +first portal that opens? + + + align:start position:0% +first portal that opens? +>> You see yourself going into the other + + align:start position:0% +>> You see yourself going into the other + + + align:start position:0% +>> You see yourself going into the other +one. + + align:start position:0% +one. + + + align:start position:0% +one. +>> You see yourself going through the other + + align:start position:0% +>> You see yourself going through the other + + + align:start position:0% +>> You see yourself going through the other +portal. It is like they force you to + + align:start position:0% +portal. It is like they force you to + + + align:start position:0% +portal. It is like they force you to +have to look at what the basic game + + align:start position:0% +have to look at what the basic game + + + align:start position:0% +have to look at what the basic game +mechanic is going to be before you can + + align:start position:0% +mechanic is going to be before you can + + + align:start position:0% +mechanic is going to be before you can +do anything else in game that's + + align:start position:0% +do anything else in game that's + + + align:start position:0% +do anything else in game that's +productive in game. uh you know you can + + align:start position:0% +productive in game. uh you know you can + + + align:start position:0% +productive in game. uh you know you can +pick up the radio but yeah + + align:start position:0% +pick up the radio but yeah + + + align:start position:0% +pick up the radio but yeah +so so you know u so you know that's that + + align:start position:0% +so so you know u so you know that's that + + + align:start position:0% +so so you know u so you know that's that +that was a design decision they could + + align:start position:0% +that was a design decision they could + + + align:start position:0% +that was a design decision they could +have made that they they could have + + align:start position:0% +have made that they they could have + + + align:start position:0% +have made that they they could have +decided not to make it they could have + + align:start position:0% +decided not to make it they could have + + + align:start position:0% +decided not to make it they could have +made you just go through that into a + + align:start position:0% +made you just go through that into a + + + align:start position:0% +made you just go through that into a +different room and you and and and a + + align:start position:0% +different room and you and and and a + + + align:start position:0% +different room and you and and and a +learning opportunity would have been + + align:start position:0% +learning opportunity would have been + + + align:start position:0% +learning opportunity would have been +lost right there um so if you got a copy + + align:start position:0% +lost right there um so if you got a copy + + + align:start position:0% +lost right there um so if you got a copy +of portal I would suggest go back and + + align:start position:0% +of portal I would suggest go back and + + + align:start position:0% +of portal I would suggest go back and +play through the the developer comment + + align:start position:0% +play through the the developer comment + + + align:start position:0% +play through the the developer comment +tries because they're they're hilarious + + align:start position:0% +tries because they're they're hilarious + + + align:start position:0% +tries because they're they're hilarious +and they're also really really good for + + align:start position:0% +and they're also really really good for + + + align:start position:0% +and they're also really really good for +demonstrating + + align:start position:0% +demonstrating + + + align:start position:0% +demonstrating +in this room. This is what we had to do + + align:start position:0% +in this room. This is what we had to do + + + align:start position:0% +in this room. This is what we had to do +in order to make people get it. Um, I'm + + align:start position:0% +in order to make people get it. Um, I'm + + + align:start position:0% +in order to make people get it. Um, I'm +also thinking of things like Mario World + + align:start position:0% +also thinking of things like Mario World + + + align:start position:0% +also thinking of things like Mario World +one where like you don't get to you + + align:start position:0% +one where like you don't get to you + + + align:start position:0% +one where like you don't get to you +don't get very far unless you get the + + align:start position:0% +don't get very far unless you get the + + + align:start position:0% +don't get very far unless you get the +basic game mechanics down and but they + + align:start position:0% +basic game mechanics down and but they + + + align:start position:0% +basic game mechanics down and but they +make it really gentle in that I don't + + align:start position:0% +make it really gentle in that I don't + + + align:start position:0% +make it really gentle in that I don't +think there are any pits that instant + + align:start position:0% +think there are any pits that instant + + + align:start position:0% +think there are any pits that instant +instantly choke you. + + align:start position:0% +instantly choke you. + + + align:start position:0% +instantly choke you. +>> Yeah, that's exactly what I was + + align:start position:0% +>> Yeah, that's exactly what I was + + + align:start position:0% +>> Yeah, that's exactly what I was +thinking. Mario World, the first Gamma + + align:start position:0% +thinking. Mario World, the first Gamma + + + align:start position:0% +thinking. Mario World, the first Gamma +Suture article we read on uh like game + + align:start position:0% +Suture article we read on uh like game + + + align:start position:0% +Suture article we read on uh like game +distractions from Rich Mario World that + + align:start position:0% +distractions from Rich Mario World that + + + align:start position:0% +distractions from Rich Mario World that +he's like you expect the same kind of + + align:start position:0% +he's like you expect the same kind of + + + align:start position:0% +he's like you expect the same kind of +actions to be consistent all the time + + align:start position:0% +actions to be consistent all the time + + + align:start position:0% +actions to be consistent all the time +jumping and I guess you kind of look at + + align:start position:0% +jumping and I guess you kind of look at + + + align:start position:0% +jumping and I guess you kind of look at +like different things there like double + + align:start position:0% +like different things there like double + + + align:start position:0% +like different things there like double +jumping like that specific puzzle + + align:start position:0% +jumping like that specific puzzle + + + align:start position:0% +jumping like that specific puzzle +also. I mean a lot of Mario's things uh + + align:start position:0% +also. I mean a lot of Mario's things uh + + + align:start position:0% +also. I mean a lot of Mario's things uh +uh worlds are made up basically as + + align:start position:0% +uh worlds are made up basically as + + + align:start position:0% +uh worlds are made up basically as +spatial puzzles, right? and it's like + + align:start position:0% +spatial puzzles, right? and it's like + + + align:start position:0% +spatial puzzles, right? and it's like +you know you have to get there but you + + align:start position:0% +you know you have to get there but you + + + align:start position:0% +you know you have to get there but you +don't know exactly how you're going to + + align:start position:0% +don't know exactly how you're going to + + + align:start position:0% +don't know exactly how you're going to +use all the mechanics that you got. + + align:start position:0% +use all the mechanics that you got. + + + align:start position:0% +use all the mechanics that you got. +>> Um in Mario 64 + + align:start position:0% +>> Um in Mario 64 + + + align:start position:0% +>> Um in Mario 64 +I think their way of solving the the + + align:start position:0% +I think their way of solving the the + + + align:start position:0% +I think their way of solving the the +impass problem of not locking off all + + align:start position:0% +impass problem of not locking off all + + + align:start position:0% +impass problem of not locking off all +the content from the game because of one + + align:start position:0% +the content from the game because of one + + + align:start position:0% +the content from the game because of one +puzzle you can't get giving you so much + + align:start position:0% +puzzle you can't get giving you so much + + + align:start position:0% +puzzle you can't get giving you so much +to do that even if they don't really + + align:start position:0% +to do that even if they don't really + + + align:start position:0% +to do that even if they don't really +tell you and even if a good 30 40% are + + align:start position:0% +tell you and even if a good 30 40% are + + + align:start position:0% +tell you and even if a good 30 40% are +going to remain mysterious to you and + + align:start position:0% +going to remain mysterious to you and + + + align:start position:0% +going to remain mysterious to you and +you're not able to figure them out + + align:start position:0% +you're not able to figure them out + + + align:start position:0% +you're not able to figure them out +there's so much to jump around between + + align:start position:0% +there's so much to jump around between + + + align:start position:0% +there's so much to jump around between +that you're never locked off from a + + align:start position:0% +that you're never locked off from a + + + align:start position:0% +that you're never locked off from a +significant amount of content. So you + + align:start position:0% +significant amount of content. So you + + + align:start position:0% +significant amount of content. So you +you you've got the hublike structure of + + align:start position:0% +you you've got the hublike structure of + + + align:start position:0% +you you've got the hublike structure of +like you can do any one of five + + align:start position:0% +like you can do any one of five + + + align:start position:0% +like you can do any one of five +different things at any given time plus + + align:start position:0% +different things at any given time plus + + + align:start position:0% +different things at any given time plus +all plus you have sort of secondary + + align:start position:0% +all plus you have sort of secondary + + + align:start position:0% +all plus you have sort of secondary +solutions like you can always go back to + + align:start position:0% +solutions like you can always go back to + + + align:start position:0% +solutions like you can always go back to +a world that you've been before and try + + align:start position:0% +a world that you've been before and try + + + align:start position:0% +a world that you've been before and try +to put all the stars. + + align:start position:0% +to put all the stars. + + + align:start position:0% +to put all the stars. +Um I think that's kind of what Brenda + + align:start position:0% +Um I think that's kind of what Brenda + + + align:start position:0% +Um I think that's kind of what Brenda +was kind of indicating of the you don't + + align:start position:0% +was kind of indicating of the you don't + + + align:start position:0% +was kind of indicating of the you don't +necessarily want if you're putting + + align:start position:0% +necessarily want if you're putting + + + align:start position:0% +necessarily want if you're putting +puzzles in your game. she was advocating + + align:start position:0% +puzzles in your game. she was advocating + + + align:start position:0% +puzzles in your game. she was advocating +for Brenda and Ian were were advocating + + align:start position:0% +for Brenda and Ian were were advocating + + + align:start position:0% +for Brenda and Ian were were advocating +for something that wouldn't that that + + align:start position:0% +for something that wouldn't that that + + + align:start position:0% +for something that wouldn't that that +wasn't necessary to progress on on to + + align:start position:0% +wasn't necessary to progress on on to + + + align:start position:0% +wasn't necessary to progress on on to +the next one. But I think that's + + align:start position:0% +the next one. But I think that's + + + align:start position:0% +the next one. But I think that's +I think that's not a requirement. I + + align:start position:0% +I think that's not a requirement. I + + + align:start position:0% +I think that's not a requirement. I +think that's a if you want to make your + + align:start position:0% +think that's a if you want to make your + + + align:start position:0% +think that's a if you want to make your +life easier, this is what you do. If you + + align:start position:0% +life easier, this is what you do. If you + + + align:start position:0% +life easier, this is what you do. If you +decide that you're up to the task, you + + align:start position:0% +decide that you're up to the task, you + + + align:start position:0% +decide that you're up to the task, you +can achieve some really amazing effects + + align:start position:0% +can achieve some really amazing effects + + + align:start position:0% +can achieve some really amazing effects +by having your puzzles narratively + + align:start position:0% +by having your puzzles narratively + + + align:start position:0% +by having your puzzles narratively +important. Um, so there's um, + + align:start position:0% +important. Um, so there's um, + + + align:start position:0% +important. Um, so there's um, +uh, has anyone heard of the game called + + align:start position:0% +uh, has anyone heard of the game called + + + align:start position:0% +uh, has anyone heard of the game called +Eternal Darkness? It's, uh, sort of the + + align:start position:0% +Eternal Darkness? It's, uh, sort of the + + + align:start position:0% +Eternal Darkness? It's, uh, sort of the +craftian horror game on the Gamecube? + + align:start position:0% +craftian horror game on the Gamecube? + + + align:start position:0% +craftian horror game on the Gamecube? +Uh, I'll sort of describe it, but + + align:start position:0% +Uh, I'll sort of describe it, but + + + align:start position:0% +Uh, I'll sort of describe it, but +basically the whole basic idea is that + + align:start position:0% +basically the whole basic idea is that + + + align:start position:0% +basically the whole basic idea is that +you have four gods all waring, all + + align:start position:0% +you have four gods all waring, all + + + align:start position:0% +you have four gods all waring, all +waring against each other. Three of them + + align:start position:0% +waring against each other. Three of them + + + align:start position:0% +waring against each other. Three of them +hate one of them, but then those three + + align:start position:0% +hate one of them, but then those three + + + align:start position:0% +hate one of them, but then those three +of them hate each other. and and most of + + align:start position:0% +of them hate each other. and and most of + + + align:start position:0% +of them hate each other. and and most of +the puzzles are just sort of + + align:start position:0% +the puzzles are just sort of + + + align:start position:0% +the puzzles are just sort of +understanding that there is this there's + + align:start position:0% +understanding that there is this there's + + + align:start position:0% +understanding that there is this there's +this mystical logic you know one god + + align:start position:0% +this mystical logic you know one god + + + align:start position:0% +this mystical logic you know one god +defeats another god defeats another god + + align:start position:0% +defeats another god defeats another god + + + align:start position:0% +defeats another god defeats another god +in a rock paper scissor circle and all + + align:start position:0% +in a rock paper scissor circle and all + + + align:start position:0% +in a rock paper scissor circle and all +of them hate this one other thing um so + + align:start position:0% +of them hate this one other thing um so + + + align:start position:0% +of them hate this one other thing um so +um early on in the game there's actually + + align:start position:0% +um early on in the game there's actually + + + align:start position:0% +um early on in the game there's actually +a puzzle there are actually a number of + + align:start position:0% +a puzzle there are actually a number of + + + align:start position:0% +a puzzle there are actually a number of +different p uh p puzzles where you see + + align:start position:0% +different p uh p puzzles where you see + + + align:start position:0% +different p uh p puzzles where you see +the symbols of these gods and you have + + align:start position:0% +the symbols of these gods and you have + + + align:start position:0% +the symbols of these gods and you have +to kind of rearrange them in the correct + + align:start position:0% +to kind of rearrange them in the correct + + + align:start position:0% +to kind of rearrange them in the correct +order and the rest of the game is all + + align:start position:0% +order and the rest of the game is all + + + align:start position:0% +order and the rest of the game is all +going to be like variations on sort of + + align:start position:0% +going to be like variations on sort of + + + align:start position:0% +going to be like variations on sort of +understanding what these gods do to each + + align:start position:0% +understanding what these gods do to each + + + align:start position:0% +understanding what these gods do to each +other. So those those are all puzzles + + align:start position:0% +other. So those those are all puzzles + + + align:start position:0% +other. So those those are all puzzles +that inform you about how the world + + align:start position:0% +that inform you about how the world + + + align:start position:0% +that inform you about how the world +works. Um that and that's that kind of + + align:start position:0% +works. Um that and that's that kind of + + + align:start position:0% +works. Um that and that's that kind of +works in two ways. One information that + + align:start position:0% +works in two ways. One information that + + + align:start position:0% +works in two ways. One information that +you've already gathered about the world + + align:start position:0% +you've already gathered about the world + + + align:start position:0% +you've already gathered about the world +about how this world works gives you + + align:start position:0% +about how this world works gives you + + + align:start position:0% +about how this world works gives you +clues on how to beat the puzzles. + + align:start position:0% +clues on how to beat the puzzles. + + + align:start position:0% +clues on how to beat the puzzles. +Beating the puzzles, finding the + + align:start position:0% +Beating the puzzles, finding the + + + align:start position:0% +Beating the puzzles, finding the +solutions for the clues gives you + + align:start position:0% +solutions for the clues gives you + + + align:start position:0% +solutions for the clues gives you +information about how the world works. + + align:start position:0% +information about how the world works. + + + align:start position:0% +information about how the world works. +And that's that's kind of like the holy + + align:start position:0% +And that's that's kind of like the holy + + + align:start position:0% +And that's that's kind of like the holy +grail of a puzzle designer in a digital + + align:start position:0% +grail of a puzzle designer in a digital + + + align:start position:0% +grail of a puzzle designer in a digital +game is that you're going to design a + + align:start position:0% +game is that you're going to design a + + + align:start position:0% +game is that you're going to design a +puzzle that's going to reinforce how the + + align:start position:0% +puzzle that's going to reinforce how the + + + align:start position:0% +puzzle that's going to reinforce how the +world works. Um we there's a chap um who + + align:start position:0% +world works. Um we there's a chap um who + + + align:start position:0% +world works. Um we there's a chap um who +gave a talk and I believe his name is + + align:start position:0% +gave a talk and I believe his name is + + + align:start position:0% +gave a talk and I believe his name is +Jeff Howard. He came to um he came to + + align:start position:0% +Jeff Howard. He came to um he came to + + + align:start position:0% +Jeff Howard. He came to um he came to +camp and gave a talk last + + align:start position:0% +camp and gave a talk last + + + align:start position:0% +camp and gave a talk last +>> last year and um and he makes this case + + align:start position:0% +>> last year and um and he makes this case + + + align:start position:0% +>> last year and um and he makes this case +that games and the logic in that that + + align:start position:0% +that games and the logic in that that + + + align:start position:0% +that games and the logic in that that +you present in games uh do basically uh + + align:start position:0% +you present in games uh do basically uh + + + align:start position:0% +you present in games uh do basically uh +the equivalent of what magic does in of + + align:start position:0% +the equivalent of what magic does in of + + + align:start position:0% +the equivalent of what magic does in of +what magic systems actually do in the + + align:start position:0% +what magic systems actually do in the + + + align:start position:0% +what magic systems actually do in the +real world. you know, um what people + + align:start position:0% +real world. you know, um what people + + + align:start position:0% +real world. you know, um what people +like like like + + align:start position:0% +like like like + + + align:start position:0% +like like like +oultists or astrologers or they + + align:start position:0% +oultists or astrologers or they + + + align:start position:0% +oultists or astrologers or they +basically give you logics on, you know, + + align:start position:0% +basically give you logics on, you know, + + + align:start position:0% +basically give you logics on, you know, +uh that that that explain how the world + + align:start position:0% +uh that that that explain how the world + + + align:start position:0% +uh that that that explain how the world +is going to work. One that may not + + align:start position:0% +is going to work. One that may not + + + align:start position:0% +is going to work. One that may not +necessarily be obvious, but if you knew + + align:start position:0% +necessarily be obvious, but if you knew + + + align:start position:0% +necessarily be obvious, but if you knew +this knowledge, you'd be able to + + align:start position:0% +this knowledge, you'd be able to + + + align:start position:0% +this knowledge, you'd be able to +understand how this will work in you. + + align:start position:0% +understand how this will work in you. + + + align:start position:0% +understand how this will work in you. +But more importantly, you'll be able to + + align:start position:0% +But more importantly, you'll be able to + + + align:start position:0% +But more importantly, you'll be able to +do things in the world that you know + + align:start position:0% +do things in the world that you know + + + align:start position:0% +do things in the world that you know +that that allow you to accomplish things + + align:start position:0% +that that allow you to accomplish things + + + align:start position:0% +that that allow you to accomplish things +uh uh that you wouldn't otherwise do. + + align:start position:0% +uh uh that you wouldn't otherwise do. + + + align:start position:0% +uh uh that you wouldn't otherwise do. +Learning a game is very much like like + + align:start position:0% +Learning a game is very much like like + + + align:start position:0% +Learning a game is very much like like +like like that. You know, it's like I + + align:start position:0% +like like that. You know, it's like I + + + align:start position:0% +like like that. You know, it's like I +don't know how this world works, but if + + align:start position:0% +don't know how this world works, but if + + + align:start position:0% +don't know how this world works, but if +I understood these particular rules, I + + align:start position:0% +I understood these particular rules, I + + + align:start position:0% +I understood these particular rules, I +could be able to accomplish greater + + align:start position:0% +could be able to accomplish greater + + + align:start position:0% +could be able to accomplish greater +things. Um and puzzles can be one of + + align:start position:0% +things. Um and puzzles can be one of + + + align:start position:0% +things. Um and puzzles can be one of +those things where where it becomes a + + align:start position:0% +those things where where it becomes a + + + align:start position:0% +those things where where it becomes a +test, right? It becomes a test of just + + align:start position:0% +test, right? It becomes a test of just + + + align:start position:0% +test, right? It becomes a test of just +exactly how well do you understand this? + + align:start position:0% +exactly how well do you understand this? + + + align:start position:0% +exactly how well do you understand this? +uh even if it's like in a combat game + + align:start position:0% +uh even if it's like in a combat game + + + align:start position:0% +uh even if it's like in a combat game +like uh Quick or God of War or + + align:start position:0% +like uh Quick or God of War or + + + align:start position:0% +like uh Quick or God of War or +something, you know, I can understand + + align:start position:0% +something, you know, I can understand + + + align:start position:0% +something, you know, I can understand +how the combat system basically works if + + align:start position:0% +how the combat system basically works if + + + align:start position:0% +how the combat system basically works if +I just keep mashing the X button or + + align:start position:0% +I just keep mashing the X button or + + + align:start position:0% +I just keep mashing the X button or +something or just like shoot everything + + align:start position:0% +something or just like shoot everything + + + align:start position:0% +something or just like shoot everything +with rockets. Um but if I really really + + align:start position:0% +with rockets. Um but if I really really + + + align:start position:0% +with rockets. Um but if I really really +understand the combat system, I might be + + align:start position:0% +understand the combat system, I might be + + + align:start position:0% +understand the combat system, I might be +able to hit something that I wouldn't + + align:start position:0% +able to hit something that I wouldn't + + + align:start position:0% +able to hit something that I wouldn't +necessarily be able to hit. I might be + + align:start position:0% +necessarily be able to hit. I might be + + + align:start position:0% +necessarily be able to hit. I might be +able to um I might be able to take down + + align:start position:0% +able to um I might be able to take down + + + align:start position:0% +able to um I might be able to take down +a a horde of enemies instead of like + + align:start position:0% +a a horde of enemies instead of like + + + align:start position:0% +a a horde of enemies instead of like +taking them down one at a time. Um I + + align:start position:0% +taking them down one at a time. Um I + + + align:start position:0% +taking them down one at a time. Um I +might be able to beat a boss. And + + align:start position:0% +might be able to beat a boss. And + + + align:start position:0% +might be able to beat a boss. And +actually a lot of boss boss battles in + + align:start position:0% +actually a lot of boss boss battles in + + + align:start position:0% +actually a lot of boss boss battles in +digital games are actually puzzles. + + align:start position:0% +digital games are actually puzzles. + + + align:start position:0% +digital games are actually puzzles. +There's not it's not how well do you + + align:start position:0% +There's not it's not how well do you + + + align:start position:0% +There's not it's not how well do you +generally react, it's can you figure out + + align:start position:0% +generally react, it's can you figure out + + + align:start position:0% +generally react, it's can you figure out +the pattern. Um but that pattern makes + + align:start position:0% +the pattern. Um but that pattern makes + + + align:start position:0% +the pattern. Um but that pattern makes +no doesn't mean anything unless you've + + align:start position:0% +no doesn't mean anything unless you've + + + align:start position:0% +no doesn't mean anything unless you've +already figured out how all your other + + align:start position:0% +already figured out how all your other + + + align:start position:0% +already figured out how all your other +combat skills work. So, a boss battle in + + align:start position:0% +combat skills work. So, a boss battle in + + + align:start position:0% +combat skills work. So, a boss battle in +Zelda only makes sense if you figured + + align:start position:0% +Zelda only makes sense if you figured + + + align:start position:0% +Zelda only makes sense if you figured +out how that one item that you picked up + + align:start position:0% +out how that one item that you picked up + + + align:start position:0% +out how that one item that you picked up +in the dungeon works really, really + + align:start position:0% +in the dungeon works really, really + + + align:start position:0% +in the dungeon works really, really +well. You know, okay, it shoots fire. + + align:start position:0% +well. You know, okay, it shoots fire. + + + align:start position:0% +well. You know, okay, it shoots fire. +That means not only does it hurt things + + align:start position:0% +That means not only does it hurt things + + + align:start position:0% +That means not only does it hurt things +from distance, it also lights certain + + align:start position:0% +from distance, it also lights certain + + + align:start position:0% +from distance, it also lights certain +things on fire. And that's what a Zelda + + align:start position:0% +things on fire. And that's what a Zelda + + + align:start position:0% +things on fire. And that's what a Zelda +boss battle basically is. Combining this + + align:start position:0% +boss battle basically is. Combining this + + + align:start position:0% +boss battle basically is. Combining this +latest ability that I got with + + align:start position:0% +latest ability that I got with + + + align:start position:0% +latest ability that I got with +everything else that you've done before + + align:start position:0% +everything else that you've done before + + + align:start position:0% +everything else that you've done before +into taking it down. That's why boss + + align:start position:0% +into taking it down. That's why boss + + + align:start position:0% +into taking it down. That's why boss +puzzle battle is kind of like a puzzle. + + align:start position:0% +puzzle battle is kind of like a puzzle. + + + align:start position:0% +puzzle battle is kind of like a puzzle. +Um, + + align:start position:0% +Um, + + + align:start position:0% +Um, +one thing I wanted to say before I go + + align:start position:0% +one thing I wanted to say before I go + + + align:start position:0% +one thing I wanted to say before I go +on, you're asking about like hints in a + + align:start position:0% +on, you're asking about like hints in a + + + align:start position:0% +on, you're asking about like hints in a +physical puzzle. And the one thing that + + align:start position:0% +physical puzzle. And the one thing that + + + align:start position:0% +physical puzzle. And the one thing that +jumped to my mind was um, a couple years + + align:start position:0% +jumped to my mind was um, a couple years + + + align:start position:0% +jumped to my mind was um, a couple years +ago, the weekly dig, I don't know if + + align:start position:0% +ago, the weekly dig, I don't know if + + + align:start position:0% +ago, the weekly dig, I don't know if +anyone reads it, it's like a free Boston + + align:start position:0% +anyone reads it, it's like a free Boston + + + align:start position:0% +anyone reads it, it's like a free Boston +newspaper. And there was a cross word + + align:start position:0% +newspaper. And there was a cross word + + + align:start position:0% +newspaper. And there was a cross word +puzzles for the longest time. They were + + align:start position:0% +puzzles for the longest time. They were + + + align:start position:0% +puzzles for the longest time. They were +thematic. And so you would have a guest + + align:start position:0% +thematic. And so you would have a guest + + + align:start position:0% +thematic. And so you would have a guest +cross lord and uh, like the first one I + + align:start position:0% +cross lord and uh, like the first one I + + + align:start position:0% +cross lord and uh, like the first one I +ever did was Hulk Hogan. So all of all + + align:start position:0% +ever did was Hulk Hogan. So all of all + + + align:start position:0% +ever did was Hulk Hogan. So all of all +of the hints in the cross word puzzle + + align:start position:0% +of the hints in the cross word puzzle + + + align:start position:0% +of the hints in the cross word puzzle +are related to Hulk Hogan. So it's a + + align:start position:0% +are related to Hulk Hogan. So it's a + + + align:start position:0% +are related to Hulk Hogan. So it's a +question of like not what does this mean + + align:start position:0% +question of like not what does this mean + + + align:start position:0% +question of like not what does this mean +to me, but what would it mean to Hulk + + align:start position:0% +to me, but what would it mean to Hulk + + + align:start position:0% +to me, but what would it mean to Hulk +Hogan? And um and they don't do it + + align:start position:0% +Hogan? And um and they don't do it + + + align:start position:0% +Hogan? And um and they don't do it +anymore, which is really depressing + + align:start position:0% +anymore, which is really depressing + + + align:start position:0% +anymore, which is really depressing +because every week it was somewhat + + align:start position:0% +because every week it was somewhat + + + align:start position:0% +because every week it was somewhat +different. And it kind of it was like a + + align:start position:0% +different. And it kind of it was like a + + + align:start position:0% +different. And it kind of it was like a +built-in hint, right? As you weren't, + + align:start position:0% +built-in hint, right? As you weren't, + + + align:start position:0% +built-in hint, right? As you weren't, +you didn't just think about it + + align:start position:0% +you didn't just think about it + + + align:start position:0% +you didn't just think about it +literally. You have to kind of + + align:start position:0% +literally. You have to kind of + + + align:start position:0% +literally. You have to kind of +contextualize it. You can think about + + align:start position:0% +contextualize it. You can think about + + + align:start position:0% +contextualize it. You can think about +all the things that come with the puzzle + + align:start position:0% +all the things that come with the puzzle + + + align:start position:0% +all the things that come with the puzzle +as potential in players introduced sense + + align:start position:0% +as potential in players introduced sense + + + align:start position:0% +as potential in players introduced sense +like the title like the play the text as + + align:start position:0% +like the title like the play the text as + + + align:start position:0% +like the title like the play the text as +you were describing the fact that it's + + align:start position:0% +you were describing the fact that it's + + + align:start position:0% +you were describing the fact that it's +in the like like the fact that you get a + + align:start position:0% +in the like like the fact that you get a + + + align:start position:0% +in the like like the fact that you get a +puzzle and mystery hunts immediately + + align:start position:0% +puzzle and mystery hunts immediately + + + align:start position:0% +puzzle and mystery hunts immediately +clues you in that maybe the solution for + + align:start position:0% +clues you in that maybe the solution for + + + align:start position:0% +clues you in that maybe the solution for +this lies in a different puzzle that not + + align:start position:0% +this lies in a different puzzle that not + + + align:start position:0% +this lies in a different puzzle that not +the one that I'm currently looking at + + align:start position:0% +the one that I'm currently looking at + + + align:start position:0% +the one that I'm currently looking at +right now because that's how mystery + + align:start position:0% +right now because that's how mystery + + + align:start position:0% +right now because that's how mystery +hunt things are. Um, + + align:start position:0% +hunt things are. Um, + + + align:start position:0% +hunt things are. Um, +uh, + + align:start position:0% +uh, + + + align:start position:0% +uh, +Metal Gear Solid is, uh, has a really, + + align:start position:0% +Metal Gear Solid is, uh, has a really, + + + align:start position:0% +Metal Gear Solid is, uh, has a really, +really bizarre one where, uh, + + align:start position:0% +really bizarre one where, uh, + + + align:start position:0% +really bizarre one where, uh, +>> look in the back case. + + align:start position:0% +>> look in the back case. + + + align:start position:0% +>> look in the back case. +>> Yes. Where they tell you, oh, there's a + + align:start position:0% +>> Yes. Where they tell you, oh, there's a + + + align:start position:0% +>> Yes. Where they tell you, oh, there's a +specific radio frequency that you need. + + align:start position:0% +specific radio frequency that you need. + + + align:start position:0% +specific radio frequency that you need. +It's written in the back of the box and + + align:start position:0% +It's written in the back of the box and + + + align:start position:0% +It's written in the back of the box and +it's like the back of the box + + align:start position:0% +it's like the back of the box + + + align:start position:0% +it's like the back of the box +or antipiriracy. + + align:start position:0% +or antipiriracy. + + + align:start position:0% +or antipiriracy. +>> Yeah. I mean, yes, but it's still a + + align:start position:0% +>> Yeah. I mean, yes, but it's still a + + + align:start position:0% +>> Yeah. I mean, yes, but it's still a +puzzle, you know. It's like, you know, + + align:start position:0% +puzzle, you know. It's like, you know, + + + align:start position:0% +puzzle, you know. It's like, you know, +to solve that. I mean, they were pretty + + align:start position:0% +to solve that. I mean, they were pretty + + + align:start position:0% +to solve that. I mean, they were pretty +obvious because uh or maybe it's just me + + align:start position:0% +obvious because uh or maybe it's just me + + + align:start position:0% +obvious because uh or maybe it's just me +because it took me about half an hour to + + align:start position:0% +because it took me about half an hour to + + + align:start position:0% +because it took me about half an hour to +figure that one out. + + align:start position:0% +figure that one out. + + + align:start position:0% +figure that one out. +>> Took me some hours. + + align:start position:0% +>> Took me some hours. + + + align:start position:0% +>> Took me some hours. +>> I mean, Middle Gear Hell did a lot of + + align:start position:0% +>> I mean, Middle Gear Hell did a lot of + + + align:start position:0% +>> I mean, Middle Gear Hell did a lot of +like meta puzzles like that. Like when + + align:start position:0% +like meta puzzles like that. Like when + + + align:start position:0% +like meta puzzles like that. Like when +when you fought Psycho Mantis the first + + align:start position:0% +when you fought Psycho Mantis the first + + + align:start position:0% +when you fought Psycho Mantis the first +time + + align:start position:0% +time + + + align:start position:0% +time +>> Well, so the thing you had to do is you + + align:start position:0% +>> Well, so the thing you had to do is you + + + align:start position:0% +>> Well, so the thing you had to do is you +had to unplug your controller and plug + + align:start position:0% +had to unplug your controller and plug + + + align:start position:0% +had to unplug your controller and plug +it into the second port because he would + + align:start position:0% +it into the second port because he would + + + align:start position:0% +it into the second port because he would +read your movements + + align:start position:0% +read your movements + + + align:start position:0% +read your movements +>> and it it was just like it was this cool + + align:start position:0% +>> and it it was just like it was this cool + + + align:start position:0% +>> and it it was just like it was this cool +like physical layer of it where like + + align:start position:0% +like physical layer of it where like + + + align:start position:0% +like physical layer of it where like +you're playing the game, you realize I + + align:start position:0% +you're playing the game, you realize I + + + align:start position:0% +you're playing the game, you realize I +have to interact with the physical + + align:start position:0% +have to interact with the physical + + + align:start position:0% +have to interact with the physical +world. so that he can't see what I'm + + align:start position:0% +world. so that he can't see what I'm + + + align:start position:0% +world. so that he can't see what I'm +doing. + + align:start position:0% +doing. + + + align:start position:0% +doing. +>> But but actually that one had a clue + + align:start position:0% +>> But but actually that one had a clue + + + align:start position:0% +>> But but actually that one had a clue +because if you had a in that particular + + align:start position:0% +because if you had a in that particular + + + align:start position:0% +because if you had a in that particular +example, that one gave you a very big + + align:start position:0% +example, that one gave you a very big + + + align:start position:0% +example, that one gave you a very big +clue because right at the beginning of + + align:start position:0% +clue because right at the beginning of + + + align:start position:0% +clue because right at the beginning of +that match, uh that boss tells you to + + align:start position:0% +that match, uh that boss tells you to + + + align:start position:0% +that match, uh that boss tells you to +put your controller on the ground and he + + align:start position:0% +put your controller on the ground and he + + + align:start position:0% +put your controller on the ground and he +said that I'm going to control this this + + align:start position:0% +said that I'm going to control this this + + + align:start position:0% +said that I'm going to control this this +controller with my mind and actually + + align:start position:0% +controller with my mind and actually + + + align:start position:0% +controller with my mind and actually +just right. + + align:start position:0% +just right. + + + align:start position:0% +just right. +>> That's only if you have DualS. So since + + align:start position:0% +>> That's only if you have DualS. So since + + + align:start position:0% +>> That's only if you have DualS. So since +it was on PlayStation, + + align:start position:0% +it was on PlayStation, + + + align:start position:0% +it was on PlayStation, +>> uh if you didn't, he just ignored that + + align:start position:0% +>> uh if you didn't, he just ignored that + + + align:start position:0% +>> uh if you didn't, he just ignored that +part and you didn't you didn't get that + + align:start position:0% +part and you didn't you didn't get that + + + align:start position:0% +part and you didn't you didn't get that +clue at all. Yeah, that and that's a + + align:start position:0% +clue at all. Yeah, that and that's a + + + align:start position:0% +clue at all. Yeah, that and that's a +problem. But but it's still it's still + + align:start position:0% +problem. But but it's still it's still + + + align:start position:0% +problem. But but it's still it's still +very + + align:start position:0% +very + + + align:start position:0% +very +>> there were other clues. + + align:start position:0% +>> there were other clues. + + + align:start position:0% +>> there were other clues. +>> There were also other clues like you + + align:start position:0% +>> There were also other clues like you + + + align:start position:0% +>> There were also other clues like you +would talk about how you had been + + align:start position:0% +would talk about how you had been + + + align:start position:0% +would talk about how you had been +playing certain games by reading saves + + align:start position:0% +playing certain games by reading saves + + + align:start position:0% +playing certain games by reading saves +on your + + align:start position:0% +on your + + + align:start position:0% +on your +>> I think it was on your notion + + align:start position:0% +>> I think it was on your notion + + + align:start position:0% +>> I think it was on your notion +of the night. + + align:start position:0% +of the night. + + + align:start position:0% +of the night. +>> Those are the ones. + + align:start position:0% +>> Those are the ones. + + + align:start position:0% +>> Those are the ones. +>> So So basically it's it's telling you + + align:start position:0% +>> So So basically it's it's telling you + + + align:start position:0% +>> So So basically it's it's telling you +it's giving you a clue that there + + align:start position:0% +it's giving you a clue that there + + + align:start position:0% +it's giving you a clue that there +there's going to be something better + + align:start position:0% +there's going to be something better + + + align:start position:0% +there's going to be something better +about the way that you're currently + + align:start position:0% +about the way that you're currently + + + align:start position:0% +about the way that you're currently +playing. Uh, the funny thing about the + + align:start position:0% +playing. Uh, the funny thing about the + + + align:start position:0% +playing. Uh, the funny thing about the +radio channel one is that that one + + align:start position:0% +radio channel one is that that one + + + align:start position:0% +radio channel one is that that one +really did not give you any clues that + + align:start position:0% +really did not give you any clues that + + + align:start position:0% +really did not give you any clues that +it was something better. It just told + + align:start position:0% +it was something better. It just told + + + align:start position:0% +it was something better. It just told +you about it at the back at the back of + + align:start position:0% +you about it at the back at the back of + + + align:start position:0% +you about it at the back at the back of +the box. It is like and it didn't tell + + align:start position:0% +the box. It is like and it didn't tell + + + align:start position:0% +the box. It is like and it didn't tell +you the back of the case, the the video + + align:start position:0% +you the back of the case, the the video + + + align:start position:0% +you the back of the case, the the video +game case, right? It's not going to be + + align:start position:0% +game case, right? It's not going to be + + + align:start position:0% +game case, right? It's not going to be +that explicit. It's a CD case + + align:start position:0% +that explicit. It's a CD case + + + align:start position:0% +that explicit. It's a CD case +specifically. + + align:start position:0% +specifically. + + + align:start position:0% +specifically. +>> Oh, CD case. + + align:start position:0% +>> Oh, CD case. + + + align:start position:0% +>> Oh, CD case. +>> Yeah, I appreciate I I was really + + align:start position:0% +>> Yeah, I appreciate I I was really + + + align:start position:0% +>> Yeah, I appreciate I I was really +confused cuz I think mine came in like a + + align:start position:0% +confused cuz I think mine came in like a + + + align:start position:0% +confused cuz I think mine came in like a +slip of paper or something. + + align:start position:0% +slip of paper or something. + + + align:start position:0% +slip of paper or something. +>> Oh, yeah. + + align:start position:0% +>> Oh, yeah. + + + align:start position:0% +>> Oh, yeah. +>> Yeah, if you buy it used or something. + + align:start position:0% +>> Yeah, if you buy it used or something. + + + align:start position:0% +>> Yeah, if you buy it used or something. +>> Wow. So, it's anti-use game protection + + align:start position:0% +>> Wow. So, it's anti-use game protection + + + align:start position:0% +>> Wow. So, it's anti-use game protection +as well. But uh yeah, mine was Yeah, I + + align:start position:0% +as well. But uh yeah, mine was Yeah, I + + + align:start position:0% +as well. But uh yeah, mine was Yeah, I +think mine actually said at the back of + + align:start position:0% +think mine actually said at the back of + + + align:start position:0% +think mine actually said at the back of +the CD case, but I was playing like a + + align:start position:0% +the CD case, but I was playing like a + + + align:start position:0% +the CD case, but I was playing like a +re-release or something and that came in + + align:start position:0% +re-release or something and that came in + + + align:start position:0% +re-release or something and that came in +the the DVD case. So, I didn't make that + + align:start position:0% +the the DVD case. So, I didn't make that + + + align:start position:0% +the the DVD case. So, I didn't make that +connection, but you know, if you look at + + align:start position:0% +connection, but you know, if you look at + + + align:start position:0% +connection, but you know, if you look at +the back of it, you see the you you + + align:start position:0% +the back of it, you see the you you + + + align:start position:0% +the back of it, you see the you you +you'll see what the radio frequency is + + align:start position:0% +you'll see what the radio frequency is + + + align:start position:0% +you'll see what the radio frequency is +in a um in the screenshot. What one of + + align:start position:0% +in a um in the screenshot. What one of + + + align:start position:0% +in a um in the screenshot. What one of +the the eight screenshots that they show + + align:start position:0% +the the eight screenshots that they show + + + align:start position:0% +the the eight screenshots that they show +to demonstrate this is what the game is + + align:start position:0% +to demonstrate this is what the game is + + + align:start position:0% +to demonstrate this is what the game is +all about. There's a number just right + + align:start position:0% +all about. There's a number just right + + + align:start position:0% +all about. There's a number just right +in there and then you keep + + align:start position:0% +in there and then you keep + + + align:start position:0% +in there and then you keep +>> behind our + + align:start position:0% +>> behind our + + + align:start position:0% +>> behind our +play of those like breakout games where + + align:start position:0% +play of those like breakout games where + + + align:start position:0% +play of those like breakout games where +you just lock in a room you have to + + align:start position:0% +you just lock in a room you have to + + + align:start position:0% +you just lock in a room you have to +>> escape the room + + align:start position:0% +>> escape the room + + + align:start position:0% +>> escape the room +and you find you like find a paper. + + align:start position:0% +and you find you like find a paper. + + + align:start position:0% +and you find you like find a paper. +>> So um actually who who doesn't know what + + align:start position:0% +>> So um actually who who doesn't know what + + + align:start position:0% +>> So um actually who who doesn't know what +these are about escape the room. + + align:start position:0% +these are about escape the room. + + + align:start position:0% +these are about escape the room. +>> Okay. So, escape the room. Actually, + + align:start position:0% +>> Okay. So, escape the room. Actually, + + + align:start position:0% +>> Okay. So, escape the room. Actually, +could we bring up something on the + + align:start position:0% +could we bring up something on the + + + align:start position:0% +could we bring up something on the +computer? Let's do that. Grab the video. + + align:start position:0% +computer? Let's do that. Grab the video. + + + align:start position:0% +computer? Let's do that. Grab the video. +Well, the video cable. I mean, the after + + align:start position:0% +Well, the video cable. I mean, the after + + + align:start position:0% +Well, the video cable. I mean, the after +my office. Oh, okay. Cool. Um, well, + + align:start position:0% +my office. Oh, okay. Cool. Um, well, + + + align:start position:0% +my office. Oh, okay. Cool. Um, well, +that + + align:start position:0% +that + + + align:start position:0% +that +um escape the room games are typically + + align:start position:0% +um escape the room games are typically + + + align:start position:0% +um escape the room games are typically +flash games. Uh, and and they're kind of + + align:start position:0% +flash games. Uh, and and they're kind of + + + align:start position:0% +flash games. Uh, and and they're kind of +like adventure games. You um only + + align:start position:0% +like adventure games. You um only + + + align:start position:0% +like adventure games. You um only +because there's usually only one room, + + align:start position:0% +because there's usually only one room, + + + align:start position:0% +because there's usually only one room, +although sometimes they have multiple + + align:start position:0% +although sometimes they have multiple + + + align:start position:0% +although sometimes they have multiple +rooms. It's a much smaller world than + + align:start position:0% +rooms. It's a much smaller world than + + + align:start position:0% +rooms. It's a much smaller world than +most adventure games, but the basic idea + + align:start position:0% +most adventure games, but the basic idea + + + align:start position:0% +most adventure games, but the basic idea +is the same. you pick up objects, you + + align:start position:0% +is the same. you pick up objects, you + + + align:start position:0% +is the same. you pick up objects, you +use objects in in in in in in a room and + + align:start position:0% +use objects in in in in in in a room and + + + align:start position:0% +use objects in in in in in in a room and +you try to make things happen, you know. + + align:start position:0% +you try to make things happen, you know. + + + align:start position:0% +you try to make things happen, you know. +Um, if you haven't made anything happen, + + align:start position:0% +Um, if you haven't made anything happen, + + + align:start position:0% +Um, if you haven't made anything happen, +you are not progressing in the game. If + + align:start position:0% +you are not progressing in the game. If + + + align:start position:0% +you are not progressing in the game. If +you made something happen, you're almost + + align:start position:0% +you made something happen, you're almost + + + align:start position:0% +you made something happen, you're almost +certainly making forward progress in the + + align:start position:0% +certainly making forward progress in the + + + align:start position:0% +certainly making forward progress in the +game. Um, and and there is actually a a + + align:start position:0% +game. Um, and and there is actually a a + + + align:start position:0% +game. Um, and and there is actually a a +guide for playing adventure games + + align:start position:0% +guide for playing adventure games + + + align:start position:0% +guide for playing adventure games +written by Rob Roberto Williams within + + align:start position:0% +written by Rob Roberto Williams within + + + align:start position:0% +written by Rob Roberto Williams within +the original series. and her guide is + + align:start position:0% +the original series. and her guide is + + + align:start position:0% +the original series. and her guide is +like, "Pick up everything, go + + align:start position:0% +like, "Pick up everything, go + + + align:start position:0% +like, "Pick up everything, go +everywhere, use everything on + + align:start position:0% +everywhere, use everything on + + + align:start position:0% +everywhere, use everything on +everything." It's like, that's actually + + align:start position:0% +everything." It's like, that's actually + + + align:start position:0% +everything." It's like, that's actually +what the escape room game is, but + + align:start position:0% +what the escape room game is, but + + + align:start position:0% +what the escape room game is, but +there's a little bit more humane escape + + align:start position:0% +there's a little bit more humane escape + + + align:start position:0% +there's a little bit more humane escape +to room game because there just not that + + align:start position:0% +to room game because there just not that + + + align:start position:0% +to room game because there just not that +many places that you can explore because + + align:start position:0% +many places that you can explore because + + + align:start position:0% +many places that you can explore because +the idea is that you're stuck in a room. + + align:start position:0% +the idea is that you're stuck in a room. + + + align:start position:0% +the idea is that you're stuck in a room. +Um, and uh, and basically it comes down + + align:start position:0% +Um, and uh, and basically it comes down + + + align:start position:0% +Um, and uh, and basically it comes down +to just use everything on everything + + align:start position:0% +to just use everything on everything + + + align:start position:0% +to just use everything on everything +until you figure out what what turns + + align:start position:0% +until you figure out what what turns + + + align:start position:0% +until you figure out what what turns +out. Rarely isn't logical. Often it + + align:start position:0% +out. Rarely isn't logical. Often it + + + align:start position:0% +out. Rarely isn't logical. Often it +often pretty entertaining because + + align:start position:0% +often pretty entertaining because + + + align:start position:0% +often pretty entertaining because +they're animation heavy. So every time + + align:start position:0% +they're animation heavy. So every time + + + align:start position:0% +they're animation heavy. So every time +you do something right, you get some + + align:start position:0% +you do something right, you get some + + + align:start position:0% +you do something right, you get some +crazy animation. I put the fish into the + + align:start position:0% +crazy animation. I put the fish into the + + + align:start position:0% +crazy animation. I put the fish into the +male slot and then out appears an + + align:start position:0% +male slot and then out appears an + + + align:start position:0% +male slot and then out appears an +octopus. + + align:start position:0% +octopus. + + + align:start position:0% +octopus. +It's like it's fun to watch. Um whereas + + align:start position:0% +It's like it's fun to watch. Um whereas + + + align:start position:0% +It's like it's fun to watch. Um whereas +the kind of combinatorily + + align:start position:0% +the kind of combinatorily + + + align:start position:0% +the kind of combinatorily +opposite of those are the grow games. + + align:start position:0% +opposite of those are the grow games. + + + align:start position:0% +opposite of those are the grow games. +>> Oh yeah. + + align:start position:0% +>> Oh yeah. + + + align:start position:0% +>> Oh yeah. +>> Um and there there is a series of games + + align:start position:0% +>> Um and there there is a series of games + + + align:start position:0% +>> Um and there there is a series of games +called Grow. Um I think the guy who does + + align:start position:0% +called Grow. Um I think the guy who does + + + align:start position:0% +called Grow. Um I think the guy who does +them called eyes maze and that's like Z. + + align:start position:0% +them called eyes maze and that's like Z. + + + align:start position:0% +them called eyes maze and that's like Z. +Um and and um and the whole basic idea + + align:start position:0% +Um and and um and the whole basic idea + + + align:start position:0% +Um and and um and the whole basic idea +is that um imagine that you have a + + align:start position:0% +is that um imagine that you have a + + + align:start position:0% +is that um imagine that you have a +flower pot and every time you add + + align:start position:0% +flower pot and every time you add + + + align:start position:0% +flower pot and every time you add +something to it, something happens. But + + align:start position:0% +something to it, something happens. But + + + align:start position:0% +something to it, something happens. But +the order in which you're adding things + + align:start position:0% +the order in which you're adding things + + + align:start position:0% +the order in which you're adding things +to it makes different things happen. + + align:start position:0% +to it makes different things happen. + + + align:start position:0% +to it makes different things happen. +>> And there are solutions basically in + + align:start position:0% +>> And there are solutions basically in + + + align:start position:0% +>> And there are solutions basically in +making the optimal number of things h + + align:start position:0% +making the optimal number of things h + + + align:start position:0% +making the optimal number of things h +happen if you if you if you do it if you + + align:start position:0% +happen if you if you if you do it if you + + + align:start position:0% +happen if you if you if you do it if you +do it right. So what you can do is not a + + align:start position:0% +do it right. So what you can do is not a + + + align:start position:0% +do it right. So what you can do is not a +mystery at all. You know, you you have I + + align:start position:0% +mystery at all. You know, you you have I + + + align:start position:0% +mystery at all. You know, you you have I +have these six things that I could add + + align:start position:0% +have these six things that I could add + + + align:start position:0% +have these six things that I could add +to my part and it doesn't and and I know + + align:start position:0% +to my part and it doesn't and and I know + + + align:start position:0% +to my part and it doesn't and and I know +that's those are the only six things I + + align:start position:0% +that's those are the only six things I + + + align:start position:0% +that's those are the only six things I +could add. The question is what order do + + align:start position:0% +could add. The question is what order do + + + align:start position:0% +could add. The question is what order do +I do them? Um and doing them in + + align:start position:0% +I do them? Um and doing them in + + + align:start position:0% +I do them? Um and doing them in +different orders gives you different + + align:start position:0% +different orders gives you different + + + align:start position:0% +different orders gives you different +different results. I feel that + + align:start position:0% +different results. I feel that + + + align:start position:0% +different results. I feel that +these these two genres are kind of + + align:start position:0% +these these two genres are kind of + + + align:start position:0% +these these two genres are kind of +linked, but they're not uh but they're + + align:start position:0% +linked, but they're not uh but they're + + + align:start position:0% +linked, but they're not uh but they're +playing off very different things. One + + align:start position:0% +playing off very different things. One + + + align:start position:0% +playing off very different things. One +of them is I don't know what I'm going + + align:start position:0% +of them is I don't know what I'm going + + + align:start position:0% +of them is I don't know what I'm going +to do. Uh, but I know that whatever I do + + align:start position:0% +to do. Uh, but I know that whatever I do + + + align:start position:0% +to do. Uh, but I know that whatever I do +is got to be in the space. And the other + + align:start position:0% +is got to be in the space. And the other + + + align:start position:0% +is got to be in the space. And the other +one is very much I know exactly what I + + align:start position:0% +one is very much I know exactly what I + + + align:start position:0% +one is very much I know exactly what I +can possibly do. I just don't know what + + align:start position:0% +can possibly do. I just don't know what + + + align:start position:0% +can possibly do. I just don't know what +order to do them. So couple of puzzles + + align:start position:0% +order to do them. So couple of puzzles + + + align:start position:0% +order to do them. So couple of puzzles +that you see online. These are fairly + + align:start position:0% +that you see online. These are fairly + + + align:start position:0% +that you see online. These are fairly +encapsulated things. One one game is one + + align:start position:0% +encapsulated things. One one game is one + + + align:start position:0% +encapsulated things. One one game is one +series of puzzles. There's no it's not + + align:start position:0% +series of puzzles. There's no it's not + + + align:start position:0% +series of puzzles. There's no it's not +like a professor kind of encyclopedia + + align:start position:0% +like a professor kind of encyclopedia + + + align:start position:0% +like a professor kind of encyclopedia +puzzles kind of thing. + + align:start position:0% + + + + align:start position:0% + +Okay. Um, let's see. I I think I'm + + align:start position:0% +Okay. Um, let's see. I I think I'm + + + align:start position:0% +Okay. Um, let's see. I I think I'm +actually going going to grab a few more + + align:start position:0% +actually going going to grab a few more + + + align:start position:0% +actually going going to grab a few more +puzzles and bring them in. But, uh, I do + + align:start position:0% +puzzles and bring them in. But, uh, I do + + + align:start position:0% +puzzles and bring them in. But, uh, I do +actually want uh, uh, to try to see + + align:start position:0% +actually want uh, uh, to try to see + + + align:start position:0% +actually want uh, uh, to try to see +whether we can put together a list of + + align:start position:0% +whether we can put together a list of + + + align:start position:0% +whether we can put together a list of +the kinds of puzzles that we haven't + + align:start position:0% +the kinds of puzzles that we haven't + + + align:start position:0% +the kinds of puzzles that we haven't +talked about today. Uh, these could be + + align:start position:0% +talked about today. Uh, these could be + + + align:start position:0% +talked about today. Uh, these could be +physical puzzles. These could be puzzles + + align:start position:0% +physical puzzles. These could be puzzles + + + align:start position:0% +physical puzzles. These could be puzzles +that you've seen in the book, but like a + + align:start position:0% +that you've seen in the book, but like a + + + align:start position:0% +that you've seen in the book, but like a +genre. Um, logic puzzles, you know, of a + + align:start position:0% +genre. Um, logic puzzles, you know, of a + + + align:start position:0% +genre. Um, logic puzzles, you know, of a +certain kind that you either really + + align:start position:0% +certain kind that you either really + + + align:start position:0% +certain kind that you either really +really like or you really really love. + + align:start position:0% +really like or you really really love. + + + align:start position:0% +really like or you really really love. +Um, and just just break up in groups of + + align:start position:0% +Um, and just just break up in groups of + + + align:start position:0% +Um, and just just break up in groups of +three, four, six, seven, eight, nine. + + align:start position:0% +three, four, six, seven, eight, nine. + + + align:start position:0% +three, four, six, seven, eight, nine. +I'm going to bring you guys to do this. + + align:start position:0% +I'm going to bring you guys to do this. + + + align:start position:0% +I'm going to bring you guys to do this. +10 12 13 15 16 17 people. 17 people. + + align:start position:0% +10 12 13 15 16 17 people. 17 people. + + + align:start position:0% +10 12 13 15 16 17 people. 17 people. +That doesn't divide at all. + + align:start position:0% +That doesn't divide at all. + + + align:start position:0% +That doesn't divide at all. +>> One group. + + align:start position:0% + + + + align:start position:0% + +>> Okay. Two or three. Groups of two or + + align:start position:0% +>> Okay. Two or three. Groups of two or + + + align:start position:0% +>> Okay. Two or three. Groups of two or +three. And just like + + align:start position:0% +three. And just like + + + align:start position:0% +three. And just like +>> uh Jason should be back. + + align:start position:0% +>> uh Jason should be back. + + + align:start position:0% +>> uh Jason should be back. +>> Okay. Then groups then groups of three. + + align:start position:0% +>> Okay. Then groups then groups of three. + + + align:start position:0% +>> Okay. Then groups then groups of three. +Um and uh right + + align:start position:0% +Um and uh right + + + align:start position:0% +Um and uh right +>> and + + align:start position:0% +>> and + + + align:start position:0% +>> and +come up with yeah just like + + align:start position:0% +come up with yeah just like + + + align:start position:0% +come up with yeah just like +>> you know just a couple of puzzles that + + align:start position:0% +>> you know just a couple of puzzles that + + + align:start position:0% +>> you know just a couple of puzzles that +we haven't discussed and you know and a + + align:start position:0% +we haven't discussed and you know and a + + + align:start position:0% +we haven't discussed and you know and a +description about what they're like and + + align:start position:0% +description about what they're like and + + + align:start position:0% +description about what they're like and +we'll just quickly run through the class + + align:start position:0% +we'll just quickly run through the class + + + align:start position:0% +we'll just quickly run through the class +to sort of like give everyone an idea of + + align:start position:0% +to sort of like give everyone an idea of + + + align:start position:0% +to sort of like give everyone an idea of +what + + align:start position:0% +what + + + align:start position:0% +what +>> a as a toy playing with a Rubik's cube + + align:start position:0% +>> a as a toy playing with a Rubik's cube + + + align:start position:0% +>> a as a toy playing with a Rubik's cube +is more fun than the algorithm to solve + + align:start position:0% +is more fun than the algorithm to solve + + + align:start position:0% +is more fun than the algorithm to solve +it. That's not fun at all in my opinion. + + align:start position:0% +it. That's not fun at all in my opinion. + + + align:start position:0% +it. That's not fun at all in my opinion. +>> Yeah. Like it's probably you can also + + align:start position:0% +>> Yeah. Like it's probably you can also + + + align:start position:0% +>> Yeah. Like it's probably you can also +solve it but there's algorithms there + + align:start position:0% +solve it but there's algorithms there + + + align:start position:0% +solve it but there's algorithms there +very + + align:start position:0% + + + + align:start position:0% + +>> yeah one of the things you're talking + + align:start position:0% +>> yeah one of the things you're talking + + + align:start position:0% +>> yeah one of the things you're talking +about was interactive fiction + + align:start position:0% +about was interactive fiction + + + align:start position:0% +about was interactive fiction +>> and uh + + align:start position:0% +>> and uh + + + align:start position:0% +>> and uh +>> like text + + align:start position:0% +>> like text + + + align:start position:0% +>> like text +>> yeah text text adventures and how um + + align:start position:0% +>> yeah text text adventures and how um + + + align:start position:0% +>> yeah text text adventures and how um +sometimes it could be considered just + + align:start position:0% +sometimes it could be considered just + + + align:start position:0% +sometimes it could be considered just +like if you're playing a regular + + align:start position:0% +like if you're playing a regular + + + align:start position:0% +like if you're playing a regular +adventure game but just with text + + align:start position:0% +adventure game but just with text + + + align:start position:0% +adventure game but just with text +instead. And so um the puzzle could be + + align:start position:0% +instead. And so um the puzzle could be + + + align:start position:0% +instead. And so um the puzzle could be +how you interact with the world or it + + align:start position:0% +how you interact with the world or it + + + align:start position:0% +how you interact with the world or it +could be trying to figure out what + + align:start position:0% +could be trying to figure out what + + + align:start position:0% +could be trying to figure out what +actions are available to the user. Like + + align:start position:0% +actions are available to the user. Like + + + align:start position:0% +actions are available to the user. Like +sometimes not all actions are there but + + align:start position:0% +sometimes not all actions are there but + + + align:start position:0% +sometimes not all actions are there but +also um in some games the nature of text + + align:start position:0% +also um in some games the nature of text + + + align:start position:0% +also um in some games the nature of text +gives you different ways to have a + + align:start position:0% +gives you different ways to have a + + + align:start position:0% +gives you different ways to have a +puzzle like in a lost pig because you're + + align:start position:0% +puzzle like in a lost pig because you're + + + align:start position:0% +puzzle like in a lost pig because you're +playing in fork. He doesn't know English + + align:start position:0% +playing in fork. He doesn't know English + + + align:start position:0% +playing in fork. He doesn't know English +very well or like doesn't doesn't have + + align:start position:0% +very well or like doesn't doesn't have + + + align:start position:0% +very well or like doesn't doesn't have +full control of language. So you're + + align:start position:0% +full control of language. So you're + + + align:start position:0% +full control of language. So you're +trying to decipher his words to figure + + align:start position:0% +trying to decipher his words to figure + + + align:start position:0% +trying to decipher his words to figure +out what he's actually saying. + + align:start position:0% +out what he's actually saying. + + + align:start position:0% +out what he's actually saying. +>> An example they can do give that to make + + align:start position:0% +>> An example they can do give that to make + + + align:start position:0% +>> An example they can do give that to make +it + + align:start position:0% +it + + + align:start position:0% +it +>> um I haven't played + + align:start position:0% +>> um I haven't played + + + align:start position:0% +>> um I haven't played +>> in that game. There's uh one part where + + align:start position:0% +>> in that game. There's uh one part where + + + align:start position:0% +>> in that game. There's uh one part where +he's describing a box and it has a slot + + align:start position:0% +he's describing a box and it has a slot + + + align:start position:0% +he's describing a box and it has a slot +and you you you put something in it and + + align:start position:0% +and you you you put something in it and + + + align:start position:0% +and you you you put something in it and +then it gives you something out. But + + align:start position:0% +then it gives you something out. But + + + align:start position:0% +then it gives you something out. But +like the way he's describing it, you + + align:start position:0% +like the way he's describing it, you + + + align:start position:0% +like the way he's describing it, you +don't really know what he's describing + + align:start position:0% +don't really know what he's describing + + + align:start position:0% +don't really know what he's describing +until you realize he's talking about a + + align:start position:0% +until you realize he's talking about a + + + align:start position:0% +until you realize he's talking about a +vending machine. + + align:start position:0% +vending machine. + + + align:start position:0% +vending machine. +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +>> He describes it as like a tall box with + + align:start position:0% +>> He describes it as like a tall box with + + + align:start position:0% +>> He describes it as like a tall box with +that slot in it. + + align:start position:0% +that slot in it. + + + align:start position:0% +that slot in it. +>> Um, and another example we were talking + + align:start position:0% +>> Um, and another example we were talking + + + align:start position:0% +>> Um, and another example we were talking +about was the game Isle, uh, which is + + align:start position:0% +about was the game Isle, uh, which is + + + align:start position:0% +about was the game Isle, uh, which is +you're you're this guy in like a grocery + + align:start position:0% +you're you're this guy in like a grocery + + + align:start position:0% +you're you're this guy in like a grocery +store and you you have it gives you like + + align:start position:0% +store and you you have it gives you like + + + align:start position:0% +store and you you have it gives you like +this big, uh, prologue and you have one + + align:start position:0% +this big, uh, prologue and you have one + + + align:start position:0% +this big, uh, prologue and you have one +action that you can do. So after you + + align:start position:0% +action that you can do. So after you + + + align:start position:0% +action that you can do. So after you +type in your one action, it tells you + + align:start position:0% +type in your one action, it tells you + + + align:start position:0% +type in your one action, it tells you +what happens and gives you an epilog + + align:start position:0% +what happens and gives you an epilog + + + align:start position:0% +what happens and gives you an epilog +and then the and then the game starts + + align:start position:0% +and then the and then the game starts + + + align:start position:0% +and then the and then the game starts +over. But then using using the + + align:start position:0% +over. But then using using the + + + align:start position:0% +over. But then using using the +information from that epilog, you you + + align:start position:0% +information from that epilog, you you + + + align:start position:0% +information from that epilog, you you +have a different choice of actions that + + align:start position:0% +have a different choice of actions that + + + align:start position:0% +have a different choice of actions that +you can take and different keywords to + + align:start position:0% +you can take and different keywords to + + + align:start position:0% +you can take and different keywords to +use. And so by playing it over and over, + + align:start position:0% +use. And so by playing it over and over, + + + align:start position:0% +use. And so by playing it over and over, +you're like uncovering more of the story + + align:start position:0% +you're like uncovering more of the story + + + align:start position:0% +you're like uncovering more of the story +until you get somewhere. + + align:start position:0% +until you get somewhere. + + + align:start position:0% +until you get somewhere. +>> So the puzzle solution. + + align:start position:0% +>> So the puzzle solution. + + + align:start position:0% +>> So the puzzle solution. +>> Yeah. Isle A. + + align:start position:0% +>> Yeah. Isle A. + + + align:start position:0% +>> Yeah. Isle A. +>> Yeah. I want to play + + align:start position:0% +>> Yeah. I want to play + + + align:start position:0% +>> Yeah. I want to play +for the + + align:start position:0% +for the + + + align:start position:0% +for the +game. + + align:start position:0% +game. + + + align:start position:0% +game. +Um, we also thought about puzzles that + + align:start position:0% +Um, we also thought about puzzles that + + + align:start position:0% +Um, we also thought about puzzles that +were + + align:start position:0% +were + + + align:start position:0% +were +games and put into a very contrived + + align:start position:0% +games and put into a very contrived + + + align:start position:0% +games and put into a very contrived +scenario like bridge puzzles or chess + + align:start position:0% +scenario like bridge puzzles or chess + + + align:start position:0% +scenario like bridge puzzles or chess +puzzles or back when the duelist + + align:start position:0% +puzzles or back when the duelist + + + align:start position:0% +puzzles or back when the duelist +magazines still existed there. Magic the + + align:start position:0% +magazines still existed there. Magic the + + + align:start position:0% +magazines still existed there. Magic the +Gathering puzzles. + + align:start position:0% +Gathering puzzles. + + + align:start position:0% +Gathering puzzles. +>> So, so like like chess puzzles are like + + align:start position:0% +>> So, so like like chess puzzles are like + + + align:start position:0% +>> So, so like like chess puzzles are like +here's this board. What was the move + + align:start position:0% +here's this board. What was the move + + + align:start position:0% +here's this board. What was the move +that that that + + align:start position:0% +that that that + + + align:start position:0% +that that that +black to win in three moves? + + align:start position:0% +black to win in three moves? + + + align:start position:0% +black to win in three moves? +>> Yeah. + + align:start position:0% +>> Yeah. + + + align:start position:0% +>> Yeah. +>> Yeah. + + align:start position:0% +>> Yeah. + + + align:start position:0% +>> Yeah. +>> Something like that. So that's like you + + align:start position:0% +>> Something like that. So that's like you + + + align:start position:0% +>> Something like that. So that's like you +you are now placing additional + + align:start position:0% +you are now placing additional + + + align:start position:0% +you are now placing additional +constraints on the game. + + align:start position:0% +constraints on the game. + + + align:start position:0% +constraints on the game. +>> Yeah, exactly. It already puts you in a + + align:start position:0% +>> Yeah, exactly. It already puts you in a + + + align:start position:0% +>> Yeah, exactly. It already puts you in a +situation like pretend you're in this + + align:start position:0% +situation like pretend you're in this + + + align:start position:0% +situation like pretend you're in this +game now. We promise you there's a way + + align:start position:0% +game now. We promise you there's a way + + + align:start position:0% +game now. We promise you there's a way +you can automatically win. You have to + + align:start position:0% +you can automatically win. You have to + + + align:start position:0% +you can automatically win. You have to +find it. + + align:start position:0% +find it. + + + align:start position:0% +find it. +>> Yeah. There's a number of uh sort of + + align:start position:0% +>> Yeah. There's a number of uh sort of + + + align:start position:0% +>> Yeah. There's a number of uh sort of +computer games like Choo Choo Rocket and + + align:start position:0% +computer games like Choo Choo Rocket and + + + align:start position:0% +computer games like Choo Choo Rocket and +everything where that's like just a + + align:start position:0% +everything where that's like just a + + + align:start position:0% +everything where that's like just a +completely second. + + align:start position:0% + + + + align:start position:0% + +>> Chuchu Rocket. Chuchu Rocket. Too rocket + + align:start position:0% +>> Chuchu Rocket. Chuchu Rocket. Too rocket + + + align:start position:0% +>> Chuchu Rocket. Chuchu Rocket. Too rocket +is a frenetic fourplayer. Um like uh + + align:start position:0% +is a frenetic fourplayer. Um like uh + + + align:start position:0% +is a frenetic fourplayer. Um like uh +>> it's it's a mice hurting game. + + align:start position:0% +>> it's it's a mice hurting game. + + + align:start position:0% +>> it's it's a mice hurting game. +>> Mice mice hurting game. + + align:start position:0% +>> Mice mice hurting game. + + + align:start position:0% +>> Mice mice hurting game. +>> Get them into rocket ships. + + align:start position:0% +>> Get them into rocket ships. + + + align:start position:0% +>> Get them into rocket ships. +>> Yeah. So they can go into space. + + align:start position:0% +>> Yeah. So they can go into space. + + + align:start position:0% +>> Yeah. So they can go into space. +>> It is + + align:start position:0% +>> It is + + + align:start position:0% +>> It is +for the dream. It's so good. + + align:start position:0% +for the dream. It's so good. + + + align:start position:0% +for the dream. It's so good. +>> Oh really? + + align:start position:0% +>> Oh really? + + + align:start position:0% +>> Oh really? +>> Really? + + align:start position:0% +>> Really? + + + align:start position:0% +>> Really? +>> The idea is just a whole bunch of mice + + align:start position:0% +>> The idea is just a whole bunch of mice + + + align:start position:0% +>> The idea is just a whole bunch of mice +wandering around the screen and each + + align:start position:0% +wandering around the screen and each + + + align:start position:0% +wandering around the screen and each +player gets to place like three arrows + + align:start position:0% +player gets to place like three arrows + + + align:start position:0% +player gets to place like three arrows +and whenever the mice run the arrow they + + align:start position:0% +and whenever the mice run the arrow they + + + align:start position:0% +and whenever the mice run the arrow they +follow the arrow. So you want to get all + + align:start position:0% +follow the arrow. So you want to get all + + + align:start position:0% +follow the arrow. So you want to get all +you like want to get the cats and the + + align:start position:0% +you like want to get the cats and the + + + align:start position:0% +you like want to get the cats and the +other chips and they eat their mice. + + align:start position:0% +other chips and they eat their mice. + + + align:start position:0% +other chips and they eat their mice. +>> And puzzle mode says you have three + + align:start position:0% +>> And puzzle mode says you have three + + + align:start position:0% +>> And puzzle mode says you have three +arrows in these particular directions. + + align:start position:0% +arrows in these particular directions. + + + align:start position:0% +arrows in these particular directions. +Figure out where to place them. As much + + align:start position:0% +Figure out where to place them. As much + + + align:start position:0% +Figure out where to place them. As much +time as you want, but there's only one + + align:start position:0% +time as you want, but there's only one + + + align:start position:0% +time as you want, but there's only one +one right answer. And that immediately + + align:start position:0% +one right answer. And that immediately + + + align:start position:0% +one right answer. And that immediately +shows you the difference between game + + align:start position:0% +shows you the difference between game + + + align:start position:0% +shows you the difference between game +and puzzle where they all + + align:start position:0% +and puzzle where they all + + + align:start position:0% +and puzzle where they all +>> cool. + + align:start position:0% +>> cool. + + + align:start position:0% +>> cool. +So uh first off, I don't like jigsaw + + align:start position:0% +So uh first off, I don't like jigsaw + + + align:start position:0% +So uh first off, I don't like jigsaw +puzzles, but Michelle loves them. And + + align:start position:0% +puzzles, but Michelle loves them. And + + + align:start position:0% +puzzles, but Michelle loves them. And +then we also talked about who donuts. + + align:start position:0% +then we also talked about who donuts. + + + align:start position:0% +then we also talked about who donuts. +And I really love redemptance because + + align:start position:0% +And I really love redemptance because + + + align:start position:0% +And I really love redemptance because +it's like what you have to pay attention + + align:start position:0% +it's like what you have to pay attention + + + align:start position:0% +it's like what you have to pay attention +to detail in the story is like the one + + align:start position:0% +to detail in the story is like the one + + + align:start position:0% +to detail in the story is like the one +thing that like I guess the example that + + align:start position:0% +thing that like I guess the example that + + + align:start position:0% +thing that like I guess the example that +we were talking about is if there's a + + align:start position:0% +we were talking about is if there's a + + + align:start position:0% +we were talking about is if there's a +mailman it happens to be on a Sunday he + + align:start position:0% +mailman it happens to be on a Sunday he + + + align:start position:0% +mailman it happens to be on a Sunday he +probably committed the crime because + + align:start position:0% +probably committed the crime because + + + align:start position:0% +probably committed the crime because +they don't have mail on Sundays like + + align:start position:0% +they don't have mail on Sundays like + + + align:start position:0% +they don't have mail on Sundays like +small details like that. + + align:start position:0% +small details like that. + + + align:start position:0% +small details like that. +>> Are you talking about mystery books or + + align:start position:0% +>> Are you talking about mystery books or + + + align:start position:0% +>> Are you talking about mystery books or +just like little paragraphs? + + align:start position:0% +just like little paragraphs? + + + align:start position:0% +just like little paragraphs? +>> Well, it's usually like a story and they + + align:start position:0% +>> Well, it's usually like a story and they + + + align:start position:0% +>> Well, it's usually like a story and they +say like, "Oh, here's the scenario. + + align:start position:0% +say like, "Oh, here's the scenario. + + + align:start position:0% +say like, "Oh, here's the scenario. +Here's the background story. Who is the + + align:start position:0% +Here's the background story. Who is the + + + align:start position:0% +Here's the background story. Who is the +who is the murder? Who's the murderer?" + + align:start position:0% +who is the murder? Who's the murderer?" + + + align:start position:0% +who is the murder? Who's the murderer?" +>> They compiled it though to you. Yeah. + + align:start position:0% +>> They compiled it though to you. Yeah. + + + align:start position:0% +>> They compiled it though to you. Yeah. +Yeah. + + align:start position:0% +Yeah. + + + align:start position:0% +Yeah. +>> Feels like you told us at parties like + + align:start position:0% +>> Feels like you told us at parties like + + + align:start position:0% +>> Feels like you told us at parties like +that like for at parties, right? + + align:start position:0% +that like for at parties, right? + + + align:start position:0% +that like for at parties, right? +>> That's very true. + + align:start position:0% +>> That's very true. + + + align:start position:0% +>> That's very true. +>> Yeah. How + + align:start position:0% +>> Yeah. How + + + align:start position:0% +>> Yeah. How +>> I didn't see you was talking for a + + align:start position:0% +>> I didn't see you was talking for a + + + align:start position:0% +>> I didn't see you was talking for a +second. That was + + align:start position:0% + + + + align:start position:0% + +talking. + + align:start position:0% + + + + align:start position:0% + +>> Did we actually + + align:start position:0% +>> Did we actually + + + align:start position:0% +>> Did we actually +you guys? + + align:start position:0% +you guys? + + + align:start position:0% +you guys? +>> Okay. All right. Uh, another puzzle we + + align:start position:0% +>> Okay. All right. Uh, another puzzle we + + + align:start position:0% +>> Okay. All right. Uh, another puzzle we +came up with was uh the the ones that + + align:start position:0% +came up with was uh the the ones that + + + align:start position:0% +came up with was uh the the ones that +you did in elementary school with like + + align:start position:0% +you did in elementary school with like + + + align:start position:0% +you did in elementary school with like +the the big grid and you would have, you + + align:start position:0% +the the big grid and you would have, you + + + align:start position:0% +the the big grid and you would have, you +know, like someone's name and maybe + + align:start position:0% +know, like someone's name and maybe + + + align:start position:0% +know, like someone's name and maybe +their favorite food and you'd be given a + + align:start position:0% +their favorite food and you'd be given a + + + align:start position:0% +their favorite food and you'd be given a +bunch of clues and you have to match + + align:start position:0% +bunch of clues and you have to match + + + align:start position:0% +bunch of clues and you have to match +them. + + align:start position:0% +them. + + + align:start position:0% +them. +>> Yeah. With like the checks and the exits + + align:start position:0% +>> Yeah. With like the checks and the exits + + + align:start position:0% +>> Yeah. With like the checks and the exits +and stuff. + + align:start position:0% +and stuff. + + + align:start position:0% +and stuff. +>> So, + + align:start position:0% +>> So, + + + align:start position:0% +>> So, +I think + + align:start position:0% +I think + + + align:start position:0% +I think +>> they're just generally called logic + + align:start position:0% +>> they're just generally called logic + + + align:start position:0% +>> they're just generally called logic +puzzles, I believe. And it's just you're + + align:start position:0% +puzzles, I believe. And it's just you're + + + align:start position:0% +puzzles, I believe. And it's just you're +given the the incomplete set of + + align:start position:0% +given the the incomplete set of + + + align:start position:0% +given the the incomplete set of +information, but enough constraints that + + align:start position:0% +information, but enough constraints that + + + align:start position:0% +information, but enough constraints that +you can figure out the rest of the + + align:start position:0% +you can figure out the rest of the + + + align:start position:0% +you can figure out the rest of the +information. And really the the way to + + align:start position:0% +information. And really the the way to + + + align:start position:0% +information. And really the the way to +solve it is just like write everybody's + + align:start position:0% +solve it is just like write everybody's + + + align:start position:0% +solve it is just like write everybody's +name, all all the characters that you're + + align:start position:0% +name, all all the characters that you're + + + align:start position:0% +name, all all the characters that you're +given in a piece of pros. Write down all + + align:start position:0% +given in a piece of pros. Write down all + + + align:start position:0% +given in a piece of pros. Write down all +the characters on one column. Write down + + align:start position:0% +the characters on one column. Write down + + + align:start position:0% +the characters on one column. Write down +all the things that you're trying to + + align:start position:0% +all the things that you're trying to + + + align:start position:0% +all the things that you're trying to +figure out like who's wearing what + + align:start position:0% +figure out like who's wearing what + + + align:start position:0% +figure out like who's wearing what +colored shirt for instance. So just + + align:start position:0% +colored shirt for instance. So just + + + align:start position:0% +colored shirt for instance. So just +write out all the colors on the other + + align:start position:0% +write out all the colors on the other + + + align:start position:0% +write out all the colors on the other +column. And just by the process of of + + align:start position:0% +column. And just by the process of of + + + align:start position:0% +column. And just by the process of of +elimination, just figuring out um + + align:start position:0% +elimination, just figuring out um + + + align:start position:0% +elimination, just figuring out um +usually these the answers are usually + + align:start position:0% +usually these the answers are usually + + + align:start position:0% +usually these the answers are usually +exclusive, right? So like if somebody's + + align:start position:0% +exclusive, right? So like if somebody's + + + align:start position:0% +exclusive, right? So like if somebody's +wearing a red shirt, the person cannot + + align:start position:0% +wearing a red shirt, the person cannot + + + align:start position:0% +wearing a red shirt, the person cannot +be wearing a green shirt. Um, you know, + + align:start position:0% +be wearing a green shirt. Um, you know, + + + align:start position:0% +be wearing a green shirt. Um, you know, +uh, so yeah, + + align:start position:0% +uh, so yeah, + + + align:start position:0% +uh, so yeah, +>> like they're like much harder on like + + align:start position:0% +>> like they're like much harder on like + + + align:start position:0% +>> like they're like much harder on like +every fourth statement is fault. Like + + align:start position:0% +every fourth statement is fault. Like + + + align:start position:0% +every fourth statement is fault. Like +you don't know one state is definitely + + align:start position:0% +you don't know one state is definitely + + + align:start position:0% +you don't know one state is definitely +false. I've seen ones where every + + align:start position:0% +false. I've seen ones where every + + + align:start position:0% +false. I've seen ones where every +statement is false except for one. They + + align:start position:0% +statement is false except for one. They + + + align:start position:0% +statement is false except for one. They +like I can bring in my book and they're + + align:start position:0% +like I can bring in my book and they're + + + align:start position:0% +like I can bring in my book and they're +just like hideous. + + align:start position:0% +just like hideous. + + + align:start position:0% +just like hideous. +>> Uh you the worst version of that is + + align:start position:0% +>> Uh you the worst version of that is + + + align:start position:0% +>> Uh you the worst version of that is +figuring out how how to see people in + + align:start position:0% +figuring out how how to see people in + + + align:start position:0% +figuring out how how to see people in +the wedding. + + align:start position:0% + + + + align:start position:0% + +>> Is that in 6034? Did that last week? + + align:start position:0% +>> Is that in 6034? Did that last week? + + + align:start position:0% +>> Is that in 6034? Did that last week? +>> Oh, cool. + + align:start position:0% + + + + align:start position:0% + +>> You guys want to throw any? + + align:start position:0% +>> You guys want to throw any? + + + align:start position:0% +>> You guys want to throw any? +>> Sure. Um, we started by trying to think + + align:start position:0% +>> Sure. Um, we started by trying to think + + + align:start position:0% +>> Sure. Um, we started by trying to think +of all the puzzles that we really + + align:start position:0% +of all the puzzles that we really + + + align:start position:0% +of all the puzzles that we really +dislike and uh we came up with a couple + + align:start position:0% +dislike and uh we came up with a couple + + + align:start position:0% +dislike and uh we came up with a couple +here. The sliding square puzzles. You + + align:start position:0% +here. The sliding square puzzles. You + + + align:start position:0% +here. The sliding square puzzles. You +have like a + + align:start position:0% +have like a + + + align:start position:0% +have like a +they're basically just a variation on a + + align:start position:0% +they're basically just a variation on a + + + align:start position:0% +they're basically just a variation on a +jigsaw puzzle where the rules are more + + align:start position:0% +jigsaw puzzle where the rules are more + + + align:start position:0% +jigsaw puzzle where the rules are more +constrained. Um, I don't like jigsaw + + align:start position:0% +constrained. Um, I don't like jigsaw + + + align:start position:0% +constrained. Um, I don't like jigsaw +puzzles either. + + align:start position:0% +puzzles either. + + + align:start position:0% +puzzles either. +Like mine did there. And then John had a + + align:start position:0% +Like mine did there. And then John had a + + + align:start position:0% +Like mine did there. And then John had a +couple like lights out. I guess there's + + align:start position:0% +couple like lights out. I guess there's + + + align:start position:0% +couple like lights out. I guess there's +a lights out + + align:start position:0% + + + + align:start position:0% + +certain areas and you have to like flip + + align:start position:0% +certain areas and you have to like flip + + + align:start position:0% +certain areas and you have to like flip +them. + + align:start position:0% +them. + + + align:start position:0% +them. +So, so you got a like like a grid of + + align:start position:0% +So, so you got a like like a grid of + + + align:start position:0% +So, so you got a like like a grid of +buttons and every button you push will + + align:start position:0% +buttons and every button you push will + + + align:start position:0% +buttons and every button you push will +invert the all the neighboring buttons + + align:start position:0% +invert the all the neighboring buttons + + + align:start position:0% +invert the all the neighboring buttons +like in I think the top bottom left and + + align:start position:0% +like in I think the top bottom left and + + + align:start position:0% +like in I think the top bottom left and +right will + + align:start position:0% + + + + align:start position:0% + +>> yeah and then I guess a similar well + + align:start position:0% +>> yeah and then I guess a similar well + + + align:start position:0% +>> yeah and then I guess a similar well +maybe not similar but there's why don't + + align:start position:0% +maybe not similar but there's why don't + + + align:start position:0% +maybe not similar but there's why don't +you describe the concentric circles + + align:start position:0% +you describe the concentric circles + + + align:start position:0% +you describe the concentric circles +>> yeah their puzzles are similar that + + align:start position:0% +>> yeah their puzzles are similar that + + + align:start position:0% +>> yeah their puzzles are similar that +we're um taking an action on um one item + + align:start position:0% +we're um taking an action on um one item + + + align:start position:0% +we're um taking an action on um one item +in the scene will um these are going to + + align:start position:0% +in the scene will um these are going to + + + align:start position:0% +in the scene will um these are going to +be dual puzzles the concentric circle + + align:start position:0% +be dual puzzles the concentric circle + + + align:start position:0% +be dual puzzles the concentric circle +ones um will uh have effects on other + + align:start position:0% +ones um will uh have effects on other + + + align:start position:0% +ones um will uh have effects on other +things in the system. And um uh + + align:start position:0% +things in the system. And um uh + + + align:start position:0% +things in the system. And um uh +typically these are used in games where + + align:start position:0% +typically these are used in games where + + + align:start position:0% +typically these are used in games where +there'll be like a center podium with a + + align:start position:0% +there'll be like a center podium with a + + + align:start position:0% +there'll be like a center podium with a +pathway leading off of um the center one + + align:start position:0% +pathway leading off of um the center one + + + align:start position:0% +pathway leading off of um the center one +side of the podium. Then there'll be a + + align:start position:0% +side of the podium. Then there'll be a + + + align:start position:0% +side of the podium. Then there'll be a +concentric circle around that a + + align:start position:0% +concentric circle around that a + + + align:start position:0% +concentric circle around that a +concentric ring with a pathway off of + + align:start position:0% +concentric ring with a pathway off of + + + align:start position:0% +concentric ring with a pathway off of +that ring and another angle and then you + + align:start position:0% +that ring and another angle and then you + + + align:start position:0% +that ring and another angle and then you +know more and more circles um to each + + align:start position:0% +know more and more circles um to each + + + align:start position:0% +know more and more circles um to each +side and uh you get to uh rotate + + align:start position:0% +side and uh you get to uh rotate + + + align:start position:0% +side and uh you get to uh rotate +individual circles and that will rotate + + align:start position:0% +individual circles and that will rotate + + + align:start position:0% +individual circles and that will rotate +the other circles in different ways. + + align:start position:0% +the other circles in different ways. + + + align:start position:0% +the other circles in different ways. +need to + + align:start position:0% +need to + + + align:start position:0% +need to +>> create every time I rotate one something + + align:start position:0% +>> create every time I rotate one something + + + align:start position:0% +>> create every time I rotate one something +else is going to rotate. + + align:start position:0% +else is going to rotate. + + + align:start position:0% +else is going to rotate. +>> Yeah. And there's always like it's + + align:start position:0% +>> Yeah. And there's always like it's + + + align:start position:0% +>> Yeah. And there's always like it's +always thrown like right before like a + + align:start position:0% +always thrown like right before like a + + + align:start position:0% +always thrown like right before like a +boss battle game is like, "Oh, damn it." + + align:start position:0% +boss battle game is like, "Oh, damn it." + + + align:start position:0% +boss battle game is like, "Oh, damn it." +>> I guess three of those are examples of + + align:start position:0% +>> I guess three of those are examples of + + + align:start position:0% +>> I guess three of those are examples of +games where like you have to take action + + align:start position:0% +games where like you have to take action + + + align:start position:0% +games where like you have to take action +on an environment, but your action has + + align:start position:0% +on an environment, but your action has + + + align:start position:0% +on an environment, but your action has +indirect effects, + + align:start position:0% +indirect effects, + + + align:start position:0% +indirect effects, +>> you know, throughout the environment and + + align:start position:0% +>> you know, throughout the environment and + + + align:start position:0% +>> you know, throughout the environment and +it's just really annoying figuring out + + align:start position:0% +it's just really annoying figuring out + + + align:start position:0% +it's just really annoying figuring out +how to optimize that. + + align:start position:0% +how to optimize that. + + + align:start position:0% +how to optimize that. +>> But they are predictable effects. It's + + align:start position:0% +>> But they are predictable effects. It's + + + align:start position:0% +>> But they are predictable effects. It's +like every time I rotate this one left, + + align:start position:0% +like every time I rotate this one left, + + + align:start position:0% +like every time I rotate this one left, +that one's going to rotate right. + + align:start position:0% +that one's going to rotate right. + + + align:start position:0% +that one's going to rotate right. +I think it's kind of funny how like the + + align:start position:0% +I think it's kind of funny how like the + + + align:start position:0% +I think it's kind of funny how like the +context has a lot to do with whether + + align:start position:0% +context has a lot to do with whether + + + align:start position:0% +context has a lot to do with whether +these puzzles are employed or not + + align:start position:0% +these puzzles are employed or not + + + align:start position:0% +these puzzles are employed or not +because like I do enjoy Professor + + align:start position:0% +because like I do enjoy Professor + + + align:start position:0% +because like I do enjoy Professor +Leighton quite a bit. + + align:start position:0% +Leighton quite a bit. + + + align:start position:0% +Leighton quite a bit. +>> Um it's like it's the most uh you know + + align:start position:0% +>> Um it's like it's the most uh you know + + + align:start position:0% +>> Um it's like it's the most uh you know +arbitrary narrative like justifying that + + align:start position:0% +arbitrary narrative like justifying that + + + align:start position:0% +arbitrary narrative like justifying that +there's puzzles in the world but like + + align:start position:0% +there's puzzles in the world but like + + + align:start position:0% +there's puzzles in the world but like +it's just fun like your intentionality + + align:start position:0% +it's just fun like your intentionality + + + align:start position:0% +it's just fun like your intentionality +when playing the game is that you're + + align:start position:0% +when playing the game is that you're + + + align:start position:0% +when playing the game is that you're +going to be solving puzzles and that has + + align:start position:0% +going to be solving puzzles and that has + + + align:start position:0% +going to be solving puzzles and that has +something as well. like in the middle. + + align:start position:0% +something as well. like in the middle. + + + align:start position:0% +something as well. like in the middle. +>> Yeah. The way that also the way that + + align:start position:0% +>> Yeah. The way that also the way that + + + align:start position:0% +>> Yeah. The way that also the way that +that is presented kind of makes it funny + + align:start position:0% +that is presented kind of makes it funny + + + align:start position:0% +that is presented kind of makes it funny +in math as well, right? So like the + + align:start position:0% +in math as well, right? So like the + + + align:start position:0% +in math as well, right? So like the +mafia goons come up to you and say, + + align:start position:0% +mafia goons come up to you and say, + + + align:start position:0% +mafia goons come up to you and say, +"We're going to stop you from coming in + + align:start position:0% +"We're going to stop you from coming in + + + align:start position:0% +"We're going to stop you from coming in +here unless you can solve this puzzle. + + align:start position:0% +here unless you can solve this puzzle. + + + align:start position:0% +here unless you can solve this puzzle. +Shouldn't you just shoot me? + + align:start position:0% +Shouldn't you just shoot me? + + + align:start position:0% +Shouldn't you just shoot me? +Solve all your problems." No. No. Solve + + align:start position:0% +Solve all your problems." No. No. Solve + + + align:start position:0% +Solve all your problems." No. No. Solve +this puzzle. + + align:start position:0% + + + + align:start position:0% + +They're making fun of themselves even. + + align:start position:0% +They're making fun of themselves even. + + + align:start position:0% +They're making fun of themselves even. +>> All right. Cool. + + align:start position:0% +>> All right. Cool. + + + align:start position:0% +>> All right. Cool. +Uh, okay. I'm not sure if we really + + align:start position:0% +Uh, okay. I'm not sure if we really + + + align:start position:0% +Uh, okay. I'm not sure if we really +commented on what we liked or didn't + + align:start position:0% +commented on what we liked or didn't + + + align:start position:0% +commented on what we liked or didn't +like, but the some things that we came + + align:start position:0% +like, but the some things that we came + + + align:start position:0% +like, but the some things that we came +up that haven't been brought up yet are, + + align:start position:0% +up that haven't been brought up yet are, + + + align:start position:0% +up that haven't been brought up yet are, +uh, cryptics, which are kind of a + + align:start position:0% +uh, cryptics, which are kind of a + + + align:start position:0% +uh, cryptics, which are kind of a +combination between like crossword and + + align:start position:0% +combination between like crossword and + + + align:start position:0% +combination between like crossword and +riddles, uh, riddles, um, comatorial + + align:start position:0% +riddles, uh, riddles, um, comatorial + + + align:start position:0% +riddles, uh, riddles, um, comatorial +games as a puzzle genre, + + align:start position:0% +games as a puzzle genre, + + + align:start position:0% +games as a puzzle genre, +um, logic puzzles in general, not just + + align:start position:0% +um, logic puzzles in general, not just + + + align:start position:0% +um, logic puzzles in general, not just +like typical logic puzzles like that. + + align:start position:0% +like typical logic puzzles like that. + + + align:start position:0% +like typical logic puzzles like that. +you can have like + + align:start position:0% +you can have like + + + align:start position:0% +you can have like +state machines or pseudohoo or any type + + align:start position:0% +state machines or pseudohoo or any type + + + align:start position:0% +state machines or pseudohoo or any type +of numerical puzzle. We also wanted to + + align:start position:0% +of numerical puzzle. We also wanted to + + + align:start position:0% +of numerical puzzle. We also wanted to +differentiate that uh a lot of those + + align:start position:0% +differentiate that uh a lot of those + + + align:start position:0% +differentiate that uh a lot of those +games or some of those games are + + align:start position:0% +games or some of those games are + + + align:start position:0% +games or some of those games are +spatially oriented and some aren't + + align:start position:0% +spatially oriented and some aren't + + + align:start position:0% +spatially oriented and some aren't +>> which we thought was an important aspect + + align:start position:0% +>> which we thought was an important aspect + + + align:start position:0% +>> which we thought was an important aspect +but not necessarily definitive of a + + align:start position:0% +but not necessarily definitive of a + + + align:start position:0% +but not necessarily definitive of a +completely different genre. + + align:start position:0% +completely different genre. + + + align:start position:0% +completely different genre. +>> I'm not sure if seen escape machine + + align:start position:0% +>> I'm not sure if seen escape machine + + + align:start position:0% +>> I'm not sure if seen escape machine +puzzle actually outside of like computer + + align:start position:0% +puzzle actually outside of like computer + + + align:start position:0% +puzzle actually outside of like computer +science text. I know some + + align:start position:0% +science text. I know some + + + align:start position:0% +science text. I know some +>> I really like + + align:start position:0% +>> I really like + + + align:start position:0% +>> I really like +>> I'll have to ask you suspect it's gonna + + align:start position:0% +>> I'll have to ask you suspect it's gonna + + + align:start position:0% +>> I'll have to ask you suspect it's gonna +be more involved than we have time for. + + align:start position:0% +be more involved than we have time for. + + + align:start position:0% +be more involved than we have time for. +>> By by combinatorial puzzles you mean + + align:start position:0% +>> By by combinatorial puzzles you mean + + + align:start position:0% +>> By by combinatorial puzzles you mean +stuff like like you have + + align:start position:0% +stuff like like you have + + + align:start position:0% +stuff like like you have +>> comtorial games like + + align:start position:0% +>> comtorial games like + + + align:start position:0% +>> comtorial games like +>> all the games that fall under comtorial + + align:start position:0% +>> all the games that fall under comtorial + + + align:start position:0% +>> all the games that fall under comtorial +game theory. + + align:start position:0% +game theory. + + + align:start position:0% +game theory. +>> Okay theoretically puzzles + + align:start position:0% +>> Okay theoretically puzzles + + + align:start position:0% +>> Okay theoretically puzzles +>> like everything. + + align:start position:0% +>> like everything. + + + align:start position:0% +>> like everything. +>> Cool. That's a lot of games. + + align:start position:0% +>> Cool. That's a lot of games. + + + align:start position:0% +>> Cool. That's a lot of games. +>> See we also have exploration. So games + + align:start position:0% +>> See we also have exploration. So games + + + align:start position:0% +>> See we also have exploration. So games +where you have to see everything around + + align:start position:0% +where you have to see everything around + + + align:start position:0% +where you have to see everything around +you to know what is available for use. + + align:start position:0% +you to know what is available for use. + + + align:start position:0% +you to know what is available for use. +Now on the the braith in the book they + + align:start position:0% +Now on the the braith in the book they + + + align:start position:0% +Now on the the braith in the book they +talked about exit Zelda. + + align:start position:0% +talked about exit Zelda. + + + align:start position:0% +talked about exit Zelda. +>> Okay. and just other so a game like + + align:start position:0% +>> Okay. and just other so a game like + + + align:start position:0% +>> Okay. and just other so a game like +situation in game that I didn't like is + + align:start position:0% +situation in game that I didn't like is + + + align:start position:0% +situation in game that I didn't like is +you're playing a game and something + + align:start position:0% +you're playing a game and something + + + align:start position:0% +you're playing a game and something +happens you don't step too fast or + + align:start position:0% +happens you don't step too fast or + + + align:start position:0% +happens you don't step too fast or +something + + align:start position:0% +something + + + align:start position:0% +something +>> and because of that you get to an + + align:start position:0% +>> and because of that you get to an + + + align:start position:0% +>> and because of that you get to an +irreversible spot where you don't have + + align:start position:0% +irreversible spot where you don't have + + + align:start position:0% +irreversible spot where you don't have +the tools necessary to beat the enemy + + align:start position:0% +the tools necessary to beat the enemy + + + align:start position:0% +the tools necessary to beat the enemy +right in front of you but you also are + + align:start position:0% +right in front of you but you also are + + + align:start position:0% +right in front of you but you also are +trapped and can't go back it happened to + + align:start position:0% +trapped and can't go back it happened to + + + align:start position:0% +trapped and can't go back it happened to +me one time it was a Star Wars night of + + align:start position:0% +me one time it was a Star Wars night of + + + align:start position:0% +me one time it was a Star Wars night of +the old republic and there's an enemy + + align:start position:0% +the old republic and there's an enemy + + + align:start position:0% +the old republic and there's an enemy +there's an enemy I couldn't go forward + + align:start position:0% +there's an enemy I couldn't go forward + + + align:start position:0% +there's an enemy I couldn't go forward +>> there was the enemy you couldn't go + + align:start position:0% +>> there was the enemy you couldn't go + + + align:start position:0% +>> there was the enemy you couldn't go +forward and the door or like there was a + + align:start position:0% +forward and the door or like there was a + + + align:start position:0% +forward and the door or like there was a +cliff so you couldn't get back up + + align:start position:0% +cliff so you couldn't get back up + + + align:start position:0% +cliff so you couldn't get back up +>> and so since I couldn't do anything I + + align:start position:0% +>> and so since I couldn't do anything I + + + align:start position:0% +>> and so since I couldn't do anything I +was forced to just completely go back to + + align:start position:0% +was forced to just completely go back to + + + align:start position:0% +was forced to just completely go back to +like the last save. + + align:start position:0% +like the last save. + + + align:start position:0% +like the last save. +>> But is that a puzzle or is that just a + + align:start position:0% +>> But is that a puzzle or is that just a + + + align:start position:0% +>> But is that a puzzle or is that just a +bug? + + align:start position:0% +bug? + + + align:start position:0% +bug? +>> I mean it was like it's it's the type + + align:start position:0% +>> I mean it was like it's it's the type + + + align:start position:0% +>> I mean it was like it's it's the type +where it's exploration and item is an + + align:start position:0% +where it's exploration and item is an + + + align:start position:0% +where it's exploration and item is an +item use. So, you need to get an item to + + align:start position:0% +item use. So, you need to get an item to + + + align:start position:0% +item use. So, you need to get an item to +go ahead and like if you had this item, + + align:start position:0% +go ahead and like if you had this item, + + + align:start position:0% +go ahead and like if you had this item, +then the enemy that you + + align:start position:0% +then the enemy that you + + + align:start position:0% +then the enemy that you +>> I think it was like a rancor or + + align:start position:0% +>> I think it was like a rancor or + + + align:start position:0% +>> I think it was like a rancor or +something. + + align:start position:0% +something. + + + align:start position:0% +something. +>> You could beat the rancor or at least + + align:start position:0% +>> You could beat the rancor or at least + + + align:start position:0% +>> You could beat the rancor or at least +put it to sleep and walk by it. But + + align:start position:0% +put it to sleep and walk by it. But + + + align:start position:0% +put it to sleep and walk by it. But +without it, you had to try and just beat + + align:start position:0% +without it, you had to try and just beat + + + align:start position:0% +without it, you had to try and just beat +it or it would kill you. + + align:start position:0% +it or it would kill you. + + + align:start position:0% +it or it would kill you. +>> Okay. + + align:start position:0% +>> Okay. + + + align:start position:0% +>> Okay. +>> Yeah. + + align:start position:0% +>> Yeah. + + + align:start position:0% +>> Yeah. +>> Okay. So, so it was an item that would + + align:start position:0% +>> Okay. So, so it was an item that would + + + align:start position:0% +>> Okay. So, so it was an item that would +have made combat easier basically, but + + align:start position:0% +have made combat easier basically, but + + + align:start position:0% +have made combat easier basically, but +then it was kind they kind of made made + + align:start position:0% +then it was kind they kind of made made + + + align:start position:0% +then it was kind they kind of made made +it this one way. + + align:start position:0% +it this one way. + + + align:start position:0% +it this one way. +>> It's like Yeah. So, so yeah. So, you see + + align:start position:0% +>> It's like Yeah. So, so yeah. So, you see + + + align:start position:0% +>> It's like Yeah. So, so yeah. So, you see +a lot of puzzle games where they have + + align:start position:0% +a lot of puzzle games where they have + + + align:start position:0% +a lot of puzzle games where they have +like easy reset, right? It's like, you + + align:start position:0% +like easy reset, right? It's like, you + + + align:start position:0% +like easy reset, right? It's like, you +know, you you you can try start trying + + align:start position:0% +know, you you you can try start trying + + + align:start position:0% +know, you you you can try start trying +to solve it and you realize you screw up + + align:start position:0% +to solve it and you realize you screw up + + + align:start position:0% +to solve it and you realize you screw up +something along the way, you hit reset + + align:start position:0% +something along the way, you hit reset + + + align:start position:0% +something along the way, you hit reset +and go back right back to the beginning. + + align:start position:0% +and go back right back to the beginning. + + + align:start position:0% +and go back right back to the beginning. +Nice of the public has no easy reset. Uh + + align:start position:0% +Nice of the public has no easy reset. Uh + + + align:start position:0% +Nice of the public has no easy reset. Uh +you live with the consequences. I guess + + align:start position:0% +you live with the consequences. I guess + + + align:start position:0% +you live with the consequences. I guess +that's what they were trying to go for. + + align:start position:0% +that's what they were trying to go for. + + + align:start position:0% +that's what they were trying to go for. +But, + + align:start position:0% +But, + + + align:start position:0% +But, +>> all right. So, we also had a loading of + + align:start position:0% +>> all right. So, we also had a loading of + + + align:start position:0% +>> all right. So, we also had a loading of +sliding puzzles either either with + + align:start position:0% +sliding puzzles either either with + + + align:start position:0% +sliding puzzles either either with +numbers or with pictures. Both of them + + align:start position:0% +numbers or with pictures. Both of them + + + align:start position:0% +numbers or with pictures. Both of them +are equally annoying. + + align:start position:0% +are equally annoying. + + + align:start position:0% +are equally annoying. +It's easy. + + align:start position:0% +It's easy. + + + align:start position:0% +It's easy. +>> But but on the other hand, Alec loves + + align:start position:0% +>> But but on the other hand, Alec loves + + + align:start position:0% +>> But but on the other hand, Alec loves +rush hour and and + + align:start position:0% +rush hour and and + + + align:start position:0% +rush hour and and +>> it's the travel. + + align:start position:0% +>> it's the travel. + + + align:start position:0% +>> it's the travel. +>> You have to slide cars out of the way to + + align:start position:0% +>> You have to slide cars out of the way to + + + align:start position:0% +>> You have to slide cars out of the way to +form a path. + + align:start position:0% +form a path. + + + align:start position:0% +form a path. +>> In Professor Leighton, there are an + + align:start position:0% +>> In Professor Leighton, there are an + + + align:start position:0% +>> In Professor Leighton, there are an +awful lot of sliding puzzles that have + + align:start position:0% +awful lot of sliding puzzles that have + + + align:start position:0% +awful lot of sliding puzzles that have +like differently shaped pieces or oddly + + align:start position:0% +like differently shaped pieces or oddly + + + align:start position:0% +like differently shaped pieces or oddly +shaped pieces, + + align:start position:0% +shaped pieces, + + + align:start position:0% +shaped pieces, +>> which is slightly more interesting or + + align:start position:0% +>> which is slightly more interesting or + + + align:start position:0% +>> which is slightly more interesting or +less annoying than sliding puzzles, but + + align:start position:0% +less annoying than sliding puzzles, but + + + align:start position:0% +less annoying than sliding puzzles, but +like regular sliding puzzles, but it's + + align:start position:0% +like regular sliding puzzles, but it's + + + align:start position:0% +like regular sliding puzzles, but it's +still incredibly frustrating. Well, I + + align:start position:0% +still incredibly frustrating. Well, I + + + align:start position:0% +still incredibly frustrating. Well, I +think the difference there is that when + + align:start position:0% +think the difference there is that when + + + align:start position:0% +think the difference there is that when +you have differently sized pieces, like + + align:start position:0% +you have differently sized pieces, like + + + align:start position:0% +you have differently sized pieces, like +when when you're doing just like a + + align:start position:0% +when when you're doing just like a + + + align:start position:0% +when when you're doing just like a +sliding puzzle where you're trying to + + align:start position:0% +sliding puzzle where you're trying to + + + align:start position:0% +sliding puzzle where you're trying to +recreate an image, there's definite + + align:start position:0% +recreate an image, there's definite + + + align:start position:0% +recreate an image, there's definite +patterns that you keep using over and + + align:start position:0% +patterns that you keep using over and + + + align:start position:0% +patterns that you keep using over and +over again because you're just like + + align:start position:0% +over again because you're just like + + + align:start position:0% +over again because you're just like +rotating spacesh + + align:start position:0% +rotating spacesh + + + align:start position:0% +rotating spacesh +>> um so it's not actually interesting. + + align:start position:0% +>> um so it's not actually interesting. + + + align:start position:0% +>> um so it's not actually interesting. +Whereas rush hour, you actually have to + + align:start position:0% +Whereas rush hour, you actually have to + + + align:start position:0% +Whereas rush hour, you actually have to +like think about how things fit + + align:start position:0% +like think about how things fit + + + align:start position:0% +like think about how things fit +together. So, one other puzzle type that + + align:start position:0% +together. So, one other puzzle type that + + + align:start position:0% +together. So, one other puzzle type that +we haven't really mentioned that I + + align:start position:0% +we haven't really mentioned that I + + + align:start position:0% +we haven't really mentioned that I +actually really enjoy is like uh + + align:start position:0% +actually really enjoy is like uh + + + align:start position:0% +actually really enjoy is like uh +pictographic puzzles where it relies on + + align:start position:0% +pictographic puzzles where it relies on + + + align:start position:0% +pictographic puzzles where it relies on +on sort of your association with visual + + align:start position:0% +on sort of your association with visual + + + align:start position:0% +on sort of your association with visual +images and like word play and stuff. + + align:start position:0% +images and like word play and stuff. + + + align:start position:0% +images and like word play and stuff. +Like for example, you'll have a puzzle + + align:start position:0% +Like for example, you'll have a puzzle + + + align:start position:0% +Like for example, you'll have a puzzle +that's just, you know, an image of an + + align:start position:0% +that's just, you know, an image of an + + + align:start position:0% +that's just, you know, an image of an +eyeball uh a bumblebee and a screenshot + + align:start position:0% +eyeball uh a bumblebee and a screenshot + + + align:start position:0% +eyeball uh a bumblebee and a screenshot +of Jiggy Dench in like in a James Bond + + align:start position:0% +of Jiggy Dench in like in a James Bond + + + align:start position:0% +of Jiggy Dench in like in a James Bond +movie. And the idea is it's IBM. + + align:start position:0% +movie. And the idea is it's IBM. + + + align:start position:0% +movie. And the idea is it's IBM. +So like I I love puzzles like that. + + align:start position:0% +So like I I love puzzles like that. + + + align:start position:0% +So like I I love puzzles like that. +>> Puzzles. + + align:start position:0% +>> Puzzles. + + + align:start position:0% +>> Puzzles. +>> Yeah. So stuff like that where where it + + align:start position:0% +>> Yeah. So stuff like that where where it + + + align:start position:0% +>> Yeah. So stuff like that where where it +relies on on someone like a human being + + align:start position:0% +relies on on someone like a human being + + + align:start position:0% +relies on on someone like a human being +actually associating information with + + align:start position:0% +actually associating information with + + + align:start position:0% +actually associating information with +something visual rather than it being + + align:start position:0% +something visual rather than it being + + + align:start position:0% +something visual rather than it being +just like a straight logic puzzle where + + align:start position:0% +just like a straight logic puzzle where + + + align:start position:0% +just like a straight logic puzzle where +you have this this you know this + + align:start position:0% +you have this this you know this + + + align:start position:0% +you have this this you know this +information and we use this to derive + + align:start position:0% +information and we use this to derive + + + align:start position:0% +information and we use this to derive +the rest of the information. + + align:start position:0% +the rest of the information. + + + align:start position:0% +the rest of the information. +>> Yeah. Re rebu + + align:start position:0% +>> Yeah. Re rebu + + + align:start position:0% +>> Yeah. Re rebu +and of course those are very language + + align:start position:0% +and of course those are very language + + + align:start position:0% +and of course those are very language +focused even though they're image based. + + align:start position:0% +focused even though they're image based. + + + align:start position:0% +focused even though they're image based. +So, uh, but like the one that has the + + align:start position:0% +So, uh, but like the one that has the + + + align:start position:0% +So, uh, but like the one that has the +two lines and then read in the middle. + + align:start position:0% +two lines and then read in the middle. + + + align:start position:0% +two lines and then read in the middle. +>> Well, you + + align:start position:0% +>> Well, you + + + align:start position:0% +>> Well, you +>> Well, things like that. Yeah. + + align:start position:0% +>> Well, things like that. Yeah. + + + align:start position:0% +>> Well, things like that. Yeah. +>> Yeah. you have reverbs where you're + + align:start position:0% +>> Yeah. you have reverbs where you're + + + align:start position:0% +>> Yeah. you have reverbs where you're +trying to like basically reconstruct + + align:start position:0% +trying to like basically reconstruct + + + align:start position:0% +trying to like basically reconstruct +something and then um I forget what uh + + align:start position:0% +something and then um I forget what uh + + + align:start position:0% +something and then um I forget what uh +the what's the classification of puzzles + + align:start position:0% +the what's the classification of puzzles + + + align:start position:0% +the what's the classification of puzzles +where you're given some assembly of + + align:start position:0% +where you're given some assembly of + + + align:start position:0% +where you're given some assembly of +images and you're trying to like you + + align:start position:0% +images and you're trying to like you + + + align:start position:0% +images and you're trying to like you +know um god uh uh if if if I if I wrote + + align:start position:0% +know um god uh uh if if if I if I wrote + + + align:start position:0% +know um god uh uh if if if I if I wrote +in what's + + align:start position:0% +in what's + + + align:start position:0% +in what's +this this is not a good puzzle but just + + align:start position:0% +this this is not a good puzzle but just + + + align:start position:0% +this this is not a good puzzle but just +to give an example if I put you know + + align:start position:0% +to give an example if I put you know + + + align:start position:0% +to give an example if I put you know +feels. + + align:start position:0% + + + + align:start position:0% + +>> Yeah, this is kind of fun. I think there + + align:start position:0% +>> Yeah, this is kind of fun. I think there + + + align:start position:0% +>> Yeah, this is kind of fun. I think there +is a a specific word for these kind of + + align:start position:0% +is a a specific word for these kind of + + + align:start position:0% +is a a specific word for these kind of +things, but the whole idea they're + + align:start position:0% +things, but the whole idea they're + + + align:start position:0% +things, but the whole idea they're +trying to reconstruct this reconstruct + + align:start position:0% +trying to reconstruct this reconstruct + + + align:start position:0% +trying to reconstruct this reconstruct +sentence from from the so um so um + + align:start position:0% +sentence from from the so um so um + + + align:start position:0% +sentence from from the so um so um +so uh yeah, I mean the these are they're + + align:start position:0% +so uh yeah, I mean the these are they're + + + align:start position:0% +so uh yeah, I mean the these are they're +usually spatial to to to to begin with, + + align:start position:0% +usually spatial to to to to begin with, + + + align:start position:0% +usually spatial to to to to begin with, +but uh I think there was a whole game + + align:start position:0% +but uh I think there was a whole game + + + align:start position:0% +but uh I think there was a whole game +show in the 80s that was just all Yeah, + + align:start position:0% +show in the 80s that was just all Yeah, + + + align:start position:0% +show in the 80s that was just all Yeah, +that's awesome. That's that's great. Um, + + align:start position:0% +that's awesome. That's that's great. Um, + + + align:start position:0% +that's awesome. That's that's great. Um, +in Australia they had a triple + + align:start position:0% +in Australia they had a triple + + + align:start position:0% +in Australia they had a triple +catchphrase which was + + align:start position:0% +catchphrase which was + + + align:start position:0% +catchphrase which was +>> I think catchphrase was the short + + align:start position:0% +>> I think catchphrase was the short + + + align:start position:0% +>> I think catchphrase was the short +>> so we we wrote a big list of different + + align:start position:0% +>> so we we wrote a big list of different + + + align:start position:0% +>> so we we wrote a big list of different +types of puzzles. So we've got let's + + align:start position:0% +types of puzzles. So we've got let's + + + align:start position:0% +types of puzzles. So we've got let's +just run through right we got lots of + + align:start position:0% +just run through right we got lots of + + + align:start position:0% +just run through right we got lots of +different sliding puzzle variants. We've + + align:start position:0% +different sliding puzzle variants. We've + + + align:start position:0% +different sliding puzzle variants. We've +got hidden object finding. If anyone's + + align:start position:0% +got hidden object finding. If anyone's + + + align:start position:0% +got hidden object finding. If anyone's +done the words wallow then it's kind of + + align:start position:0% +done the words wallow then it's kind of + + + align:start position:0% +done the words wallow then it's kind of +a similar deal. Um we have riddles + + align:start position:0% +a similar deal. Um we have riddles + + + align:start position:0% +a similar deal. Um we have riddles +various kinds of logic puzzles + + align:start position:0% +various kinds of logic puzzles + + + align:start position:0% +various kinds of logic puzzles +particularly two which we've mentioned + + align:start position:0% +particularly two which we've mentioned + + + align:start position:0% +particularly two which we've mentioned +before somebody who is has several + + align:start position:0% +before somebody who is has several + + + align:start position:0% +before somebody who is has several +people witnesses give statements one of + + align:start position:0% +people witnesses give statements one of + + + align:start position:0% +people witnesses give statements one of +them's a liar which one's a liar so find + + align:start position:0% +them's a liar which one's a liar so find + + + align:start position:0% +them's a liar which one's a liar so find +an inconsistent person and there's the + + align:start position:0% +an inconsistent person and there's the + + + align:start position:0% +an inconsistent person and there's the +um thing with property X is next to + + align:start position:0% +um thing with property X is next to + + + align:start position:0% +um thing with property X is next to +thing with property Y what order are + + align:start position:0% +thing with property Y what order are + + + align:start position:0% +thing with property Y what order are +they sitting in that kind of puzzle + + align:start position:0% +they sitting in that kind of puzzle + + + align:start position:0% +they sitting in that kind of puzzle +there's a million of them in professor + + align:start position:0% + + + + align:start position:0% + +there's um these kinds of + + align:start position:0% +there's um these kinds of + + + align:start position:0% +there's um these kinds of +um unraveling or reverse engineering + + align:start position:0% +um unraveling or reverse engineering + + + align:start position:0% +um unraveling or reverse engineering +type puzzles where some system has been + + align:start position:0% +type puzzles where some system has been + + + align:start position:0% +type puzzles where some system has been +permuted and you have to restore it to + + align:start position:0% +permuted and you have to restore it to + + + align:start position:0% +permuted and you have to restore it to +its original state of which Rubik's cube + + align:start position:0% +its original state of which Rubik's cube + + + align:start position:0% +its original state of which Rubik's cube +is like the canonical example I guess + + align:start position:0% +is like the canonical example I guess + + + align:start position:0% +is like the canonical example I guess +but then there's a bunch of other + + align:start position:0% +but then there's a bunch of other + + + align:start position:0% +but then there's a bunch of other +different work on how chess games can + + align:start position:0% +different work on how chess games can + + + align:start position:0% +different work on how chess games can +fit in that can + + align:start position:0% +fit in that can + + + align:start position:0% +fit in that can +>> there's like tile rotation and swapping + + align:start position:0% +>> there's like tile rotation and swapping + + + align:start position:0% +>> there's like tile rotation and swapping +puzzles like one example of this is + + align:start position:0% +puzzles like one example of this is + + + align:start position:0% +puzzles like one example of this is +hacking but then there are a million + + align:start position:0% +hacking but then there are a million + + + align:start position:0% +hacking but then there are a million +other variations on exchanging tiles or + + align:start position:0% +other variations on exchanging tiles or + + + align:start position:0% +other variations on exchanging tiles or +swapping them around or this kind of + + align:start position:0% +swapping them around or this kind of + + + align:start position:0% +swapping them around or this kind of +thing. Lots of different kinds of math + + align:start position:0% +thing. Lots of different kinds of math + + + align:start position:0% +thing. Lots of different kinds of math +puzzles. Um, this particular word + + align:start position:0% +puzzles. Um, this particular word + + + align:start position:0% +puzzles. Um, this particular word +transformation puzzle type that I that I + + align:start position:0% +transformation puzzle type that I that I + + + align:start position:0% +transformation puzzle type that I that I +used to see all the time when I was a + + align:start position:0% +used to see all the time when I was a + + + align:start position:0% +used to see all the time when I was a +kid where you by changing one letter of + + align:start position:0% +kid where you by changing one letter of + + + align:start position:0% +kid where you by changing one letter of +a word per step, you have to transform + + align:start position:0% +a word per step, you have to transform + + + align:start position:0% +a word per step, you have to transform +one word into another. Um, mazes, + + align:start position:0% +one word into another. Um, mazes, + + + align:start position:0% +one word into another. Um, mazes, +jigsaw puzzles, + + align:start position:0% +jigsaw puzzles, + + + align:start position:0% +jigsaw puzzles, +>> code breaking, nobody even mentioned + + align:start position:0% +>> code breaking, nobody even mentioned + + + align:start position:0% +>> code breaking, nobody even mentioned +yet. Um, and then also these kind of + + align:start position:0% +yet. Um, and then also these kind of + + + align:start position:0% +yet. Um, and then also these kind of +thought experimenty type puzzles. I + + align:start position:0% +thought experimenty type puzzles. I + + + align:start position:0% +thought experimenty type puzzles. I +don't know how else to categorize them. + + align:start position:0% +don't know how else to categorize them. + + + align:start position:0% +don't know how else to categorize them. +Give us an example. + + align:start position:0% +Give us an example. + + + align:start position:0% +Give us an example. +>> All right. So, + + align:start position:0% + + + + align:start position:0% + +I'm trying to remember + + align:start position:0% +I'm trying to remember + + + align:start position:0% +I'm trying to remember +how this works, but I think it is. Does + + align:start position:0% +how this works, but I think it is. Does + + + align:start position:0% +how this works, but I think it is. Does +this one This one popped on up on Day + + align:start position:0% +this one This one popped on up on Day + + + align:start position:0% +this one This one popped on up on Day +Nine's podcast the other day. I don't + + align:start position:0% +Nine's podcast the other day. I don't + + + align:start position:0% +Nine's podcast the other day. I don't +want to give it because otherwise + + align:start position:0% +want to give it because otherwise + + + align:start position:0% +want to give it because otherwise +>> if I get it wrong, then people will go, + + align:start position:0% +>> if I get it wrong, then people will go, + + + align:start position:0% +>> if I get it wrong, then people will go, +"Oh my god." and try and puzzle it out. + + align:start position:0% +"Oh my god." and try and puzzle it out. + + + align:start position:0% +"Oh my god." and try and puzzle it out. +>> Let me see if I can. + + align:start position:0% +>> Let me see if I can. + + + align:start position:0% +>> Let me see if I can. +>> So, it has to do with a piece of string + + align:start position:0% +>> So, it has to do with a piece of string + + + align:start position:0% +>> So, it has to do with a piece of string +and burning. + + align:start position:0% +and burning. + + + align:start position:0% +and burning. +>> Oh, the 15 minutes. + + align:start position:0% +>> Oh, the 15 minutes. + + + align:start position:0% +>> Oh, the 15 minutes. +>> Yeah. + + align:start position:0% +>> Yeah. + + + align:start position:0% +>> Yeah. +>> Do you remember Do you remember exactly + + align:start position:0% +>> Do you remember Do you remember exactly + + + align:start position:0% +>> Do you remember Do you remember exactly +how? + + align:start position:0% +how? + + + align:start position:0% +how? +>> Yeah. You okay? You have two pieces of + + align:start position:0% +>> Yeah. You okay? You have two pieces of + + + align:start position:0% +>> Yeah. You okay? You have two pieces of +string. Uh you know that the whole + + align:start position:0% +string. Uh you know that the whole + + + align:start position:0% +string. Uh you know that the whole +string takes an hour to burn. Uh but + + align:start position:0% +string takes an hour to burn. Uh but + + + align:start position:0% +string takes an hour to burn. Uh but +it's not linear. So like you don't it's + + align:start position:0% +it's not linear. So like you don't it's + + + align:start position:0% +it's not linear. So like you don't it's +not linear. Uh you have an infinite + + align:start position:0% +not linear. Uh you have an infinite + + + align:start position:0% +not linear. Uh you have an infinite +supply of matches. How can you measure + + align:start position:0% +supply of matches. How can you measure + + + align:start position:0% +supply of matches. How can you measure +15 minutes with the strength? + + align:start position:0% +15 minutes with the strength? + + + align:start position:0% +15 minutes with the strength? +>> Those are lateral thinking puzzles. + + align:start position:0% +>> Those are lateral thinking puzzles. + + + align:start position:0% +>> Those are lateral thinking puzzles. +Yeah, they're all thinking puzzles. I + + align:start position:0% +Yeah, they're all thinking puzzles. I + + + align:start position:0% +Yeah, they're all thinking puzzles. I +guess + + align:start position:0% +guess + + + align:start position:0% +guess +>> I think they're I I would classify this + + align:start position:0% +>> I think they're I I would classify this + + + align:start position:0% +>> I think they're I I would classify this +under riddles, but we have two identic + + align:start position:0% +under riddles, but we have two identic + + + align:start position:0% +under riddles, but we have two identic +>> identical identical pieces. + + align:start position:0% +>> identical identical pieces. + + + align:start position:0% +>> identical identical pieces. +>> They both No, they're identical, but + + align:start position:0% +>> They both No, they're identical, but + + + align:start position:0% +>> They both No, they're identical, but +they both take an hour. + + align:start position:0% +they both take an hour. + + + align:start position:0% +they both take an hour. +>> They don't have to. + + align:start position:0% +>> They don't have to. + + + align:start position:0% +>> They don't have to. +>> They don't have to be, but they both + + align:start position:0% +>> They don't have to be, but they both + + + align:start position:0% +>> They don't have to be, but they both +take an hour to burn. Nonidently, + + align:start position:0% +take an hour to burn. Nonidently, + + + align:start position:0% +take an hour to burn. Nonidently, +>> couldn't you just be lighting matches + + align:start position:0% +>> couldn't you just be lighting matches + + + align:start position:0% +>> couldn't you just be lighting matches +the entire time and see how many matches + + align:start position:0% +the entire time and see how many matches + + + align:start position:0% +the entire time and see how many matches +you can burn an hour and after that just + + align:start position:0% +you can burn an hour and after that just + + + align:start position:0% +you can burn an hour and after that just +take that number? No, but like + + align:start position:0% + + + + align:start position:0% + +>> but then how are you going to measure + + align:start position:0% +>> but then how are you going to measure + + + align:start position:0% +>> but then how are you going to measure +that original hour? + + align:start position:0% +that original hour? + + + align:start position:0% +that original hour? +>> This this assume you want to measure. + + align:start position:0% +>> This this assume you want to measure. + + + align:start position:0% +>> This this assume you want to measure. +>> But you know that thing takes an hour to + + align:start position:0% +>> But you know that thing takes an hour to + + + align:start position:0% +>> But you know that thing takes an hour to +burn. Yeah, + + align:start position:0% +burn. Yeah, + + + align:start position:0% +burn. Yeah, +>> the whole thing. + + align:start position:0% +>> the whole thing. + + + align:start position:0% +>> the whole thing. +>> It takes slightly longer than the amount + + align:start position:0% +>> It takes slightly longer than the amount + + + align:start position:0% +>> It takes slightly longer than the amount +of time. + + align:start position:0% +of time. + + + align:start position:0% +of time. +Well, we could, but then it would be + + align:start position:0% +Well, we could, but then it would be + + + align:start position:0% +Well, we could, but then it would be +nice to give people time to think about + + align:start position:0% +nice to give people time to think about + + + align:start position:0% +nice to give people time to think about +it, too. So, so + + align:start position:0% +it, too. So, so + + + align:start position:0% +it, too. So, so +answer on Wednesday. \ No newline at end of file diff --git a/15HVevXRsBA.txt b/15HVevXRsBA.txt new file mode 100644 index 0000000000000000000000000000000000000000..98e42e906c81825f8f34d56ff67a8041a177b9dd --- /dev/null +++ b/15HVevXRsBA.txt @@ -0,0 +1,1743 @@ +Last time we saw things about +gradients and directional + +derivatives. +Before that we studied how to + +look for minima and maxima of +functions of several variables. + +And today we are going to look +again at min/max problems but in + +a different setting, +namely, one for variables that + +are not independent. +And so what we will see is you + +may have heard of Lagrange +multipliers. + +And this is the one point in +the term when I can shine with + +my French accent and say +Lagrange's name properly. + +OK. +What are Lagrange multipliers + +about? +Well, the goal is to minimize + +or maximize a function of +several variables. + +Let's say, for example, +f of x, y, z, + +but where these variables are +no longer independent. + +They are not independent. +That means that there is a + +relation between them. +The relation is maybe some + +equation of the form g of x, +y, z equals some constant. + +You take the relation between +x, y, z, you call that g and + +that gives you the constraint. +And your goal is to minimize f + +only of those values of x, +y, z that satisfy the + +constraint. +What is one way to do that? + +Well, one to do that, +if the constraint is very + +simple, we can maybe solve for +one of the variables. + +Maybe we can solve this +equation for one of the + +variables, plug it back into f, +and then we have a usual + +min/max problem that we have +seen how to do. + +The problem is sometimes you +cannot actually solve for x, + +y, z in here because this +condition is too complicated and + +then we need a new method. +That is what we are going to do. + +Why would we care about that? +Well, one example is actually + +in physics. +Maybe you have seen in + +thermodynamics that you study +quantities about gases, + +and those quantities that +involve pressure, + +volume and temperature. +And pressure, + +volume and temperature are not +independent of each other. + +I mean you know probably the +equation PV = NRT. + +And, of course, +there you could actually solve + +to express things in terms of +one or the other. + +But sometimes it is more +convenient to keep all three + +variables but treat them as +constrained. + +It is just an example of a +situation where you might want + +to do this. +Anyway, we will look mostly at + +particular examples, +but just to point out that this + +is useful when you study guesses +in physics. + +The first observation is we +cannot use our usual method of + +looking for critical points of +f. + +Because critical points of f +typically will not satisfy this + +condition and so won't be good +solutions. + +We need something else. +Let's look at an example, + +and we will see how that leads +us to the method. + +For example, +let's say that I want to find + +the point closest to the origin +-- -- on the hyperbola xy equals + +3 in the plane. +That means I have this + +hyperbola, and I am asking +myself what is the point on it + +that is the closest to the +origin? + +I mean we can solve this by +elementary geometry, + +we don't need actually Lagrange +multipliers, + +but we are going to do it with +Lagrange multipliers because it + +is a pretty good example. +What does it mean? + +Well, it means that we want to +minimize distance to the origin. + +What is the distance to the +origin? + +If I have a point, +at coordinates (x, + +y) and then the distance to the +origin is square root of x + +squared plus y squared. +Well, do we really want to + +minimize that or can we minimize +something easier? + +Yeah. +Maybe we can minimize the + +square of a distance. +Let's forget this guy and + +instead -- Actually, +we will minimize f of x, + +y equals x squared plus y +squared, + +that looks better, +subject to the constraint xy = + +3. +And so we will call this thing + +g of x, y to illustrate the +general method. + +Let's look at a picture. +Here you can see in yellow the + +hyperbola xy equals three. +And we are going to look for + +the points that are the closest +to the origin. + +What can we do? +Well, for example, + +we can plot the function x +squared plus y squared, + +function f. +That is the contour plot of f + +with a hyperbola on top of it. +Now let's see what we can do + +with that. +Well, let's ask ourselves, + +for example, +if I look at points where f + +equals 20 now. +I think I am at 20 but you + +cannot really see it. +That is a circle with a point + +whose distant square is 20. +Well, can I find a solution if + +I am on the hyperbola? +Yes, there are four points at + +this distance. +Can I do better? + +Well, let's decrease for +distance. + +Yes, we can still find points +on the hyperbola and so on. + +Except if we go too low then +there are no points on this + +circle anymore in the hyperbola. +If we decrease the value of f + +that we want to look at that +will somehow limit value beyond + +which we cannot go, +and that is the minimum of f. + +We are trying to look for the +smallest value of f that will + +actually be realized on the +hyperbola. + +When does that happen? +Well, I have to backtrack a + +little bit. +It seems like the limiting case + +is basically here. +It is when the circle is + +tangent to the hyperbola. +That is the smallest circle + +that will hit the hyperbola. +If I take a larger value of f, + +I will have solutions. +If I take a smaller value of f, + +I will not have any solutions +anymore. + +So, that is the situation that +we want to solve for. + +How do we find that minimum? +Well, a key observation that is + +valid on this picture, +and that actually remain true + +in the completely general case, +is that when we have a minimum + +the level curve of f is actually +tangent to our hyperbola. + +It is tangent to the set of +points where x, + +y equals three, +to the hyperbola. + +Let's write that down. +We observe that at the minimum + +the level curve of f is tangent +to the hyperbola. + +Remember, the hyperbola is +given by the equal g equals + +three, so it is a level curve of +g. + +We have a level curve of f and +a level curve of g that are + +tangent to each other. +And I claim that is going to be + +the general situation that we +are interested in. + +How do we try to solve for +points where this happens? + +How do we find x, +y where the level curves of f + +and g are tangent to each other? +Let's think for a second. + +If the two level curves are +tangent to each other that means + +they have the same tangent line. +That means that the normal + +vectors should be parallel. +Let me maybe draw a picture + +here. +This is the level curve maybe f + +equals something. +And this is the level curve g + +equals constant. +Here my constant is three. + +Well, if I look for gradient +vectors, the gradient of f will + +be perpendicular to the level +curve of f. + +The gradient of g will be +perpendicular to the level curve + +of g. +They don't have any reason to + +be of the same size, +but they have to be parallel to + +each other. +Of course, they could also be + +parallel pointing in opposite +directions. + +But the key point is that when +this happens the gradient of f + +is parallel to the gradient of +g. + +Well, let's check that. +Here is a point. + +And I can plot the gradient of +f in blue. + +The gradient of g in yellow. +And you see, + +in most of these places, +somehow the two gradients are + +not really parallel. +Actually, I should not be + +looking at random points. +I should be looking only on the + +hyperbola. +I want points on the hyperbola + +where the two gradients are +parallel. + +Well, when does that happen? +Well, it looks like it will + +happen here. +When I am at a minimum, + +the two gradient vectors are +parallel. + +It is not really proof. +It is an example that seems to + +be convincing. +So far things work pretty well. + +How do we decide if two vectors +are parallel? + +Well, they are parallel when +they are proportional to each + +other. +You can write one of them as a + +constant times the other one, +and that constant usually one + +uses the Greek letter lambda. +I don't know if you have seen + +it before. +It is the Greek letter for L. + +And probably, +I am sure, it is somebody's + +idea of paying tribute to +Lagrange by putting an L in + +there. +Lambda is just a constant. + +And we are looking for a scalar +lambda and points x and y where + +this holds. +In fact, + +what we are doing is replacing +min/max problems in two + +variables with a constraint +between them by a set of + +equations involving, +you will see, three variables. + +We had min/max with two +variables x, y, + +but no independent. +We had a constraint g of x, + +y equals constant. +And that becomes something new. + +That becomes a system of +equations where we have to + +solve, well, let's write down +what it means for gradient f to + +be proportional to gradient g. +That means that f sub x should + +be lambda times g sub x, +and f sub y should be lambda + +times g sub y. +Because the gradient vectors + +here are f sub x, +f sub y and g sub x, + +g sub y. +If you have a third variable z + +then you have also an equation f +sub z equals lambda g sub z. + +Now, let's see. +How many unknowns do we have in + +these equations? +Well, there is x, + +there is y and there is lambda. +We have three unknowns and have + +only two equations. +Something is missing. + +Well, I mean x and y are not +actually independent. + +They are related by the +equation g of x, + +y equals c, so we need to add +the constraint g equals c. + +And now we have three equations +involving three variables. + +Let's see how that works. +Here remember we have f equals + +x squared y squared and g = xy. +What is f sub x? + +It is going to be 2x equals +lambda times, + +what is g sub x, +y. + +Maybe I should write here f sub +x equals lambda g sub x just to + +remind you. +Then we have f sub y equals + +lambda g sub y. +F sub y is 2y equals lambda + +times g sub y is x. +And then our third equation g + +equals c becomes xy equals +three. + +So, that is what you would have +to solve. + +Any questions at this point? +No. + +Yes? +How do I know the direction of + +a gradient? +Do you mean how do I know that + +it is perpendicular to a level +curve? + +Oh, how do I know if it points +in that direction on the + +opposite one? +Well, that depends. + +I mean we'd seen in last time, +but the gradient is + +perpendicular to the level and +points towards higher values of + +a function. +So it could be -- Wait. + +What did I have? +It could be that my gradient + +vectors up there actually point +in opposite directions. + +It doesn't matter to me because +it will still look the same in + +terms of the equation, +just lambda will be positive or + +negative, depending on the case. +I can handle both situations. + +It's not a problem. +I can allow lambda to be + +positive or negative. +Well, in this example, + +it looks like lambda will be +positive. + +If you look at the picture on +the plot. + +Yes? +Well, because actually they are + +not equal to each other. +If you look at this point where + +the hyperbola and the circle +touch each other, + +first of all, +I don't know which circle I am + +going to look at. +I am trying to solve, + +actually, for the radius of the +circle. + +I am trying to find what the +minimum value of f is. + +And, second, +at that point, + +the value of f and the value of +g are not equal. + +g is equal to three because I +want the hyperbola x equals + +three. +The value of f will be the + +square of a distance, +whatever that is. + +I think it will end up being 6, +but we will see. + +So, you cannot really set them +equal because you don't know + +what f is equal to in advance. +Yes? + +Not quite. +Actually, here I am just using + +this idea of finding a point +closest to the origin to + +illustrate an example of a +min/max problem. + +The general problem we are +trying to solve is minimize f + +subject to g equals constant. +And what we are going to do for + +that is we are really going to +say instead let's look at places + +where gradient f and gradient g +are parallel to each other and + +solve for equations of that. +I think we completely lose the + +notion of closest point if we +just look at these equations. + +We don't really say anything +about closest points anymore. + +Of course, that is what they +mean in the end. + +But, in the general setting, +there is no closest point + +involved anymore. +OK. + +Yes? +Yes. + +It is always going to be the +case that, + +at the minimum, +or at the maximum of a function + +subject to a constraint, +the level curves of f and the + +level curves of g will be +tangent to each other. + +That is the basis for this +method. + +I am going to justify that soon. +It could be minimum or maximum. + +In three-dimensions it could +even be a saddle point. + +And, in fact, +I should say in advance, + +this method will not tell us +whether it is a minimum or a + +maximum. +We do not have any way of + +knowing, except for testing +values. + +We cannot use second derivative +tests or anything like that. + +I will get back to that. +Yes? + +Yes. +Here you can set y equals to + +favor x. +Then you can minimize x squared + +plus nine over x squared. +In general, if I am trying to + +solve a more complicated +problem, I might not be able to + +solve. +I am doing an example where, + +indeed, here you could solve +and remove one variable, + +but you cannot always do that. +And this method will still work. + +The other one won't. +OK. + +I don't see any other questions. +Are there any other questions? + +No. +OK. + +I see a lot of students +stretching and so on, + +so it is very confusing for me. +How do we solve these equations? + +Well, the answer is in general +we might be in deep trouble. + +There is no general method for +solving the equations that you + +get from this method. +You just have to think about + +them. +Sometimes it will be very easy. + +Sometimes it will be so hard +that you cannot actually do it + +without the computer. +Sometimes it will be just hard + +enough to be on Part B of this +week's problem set. + +I claim in this case we can +actually do it without so much + +trouble, because actually we can +think of this as a two by two + +linear system in x and y. +Well, let me do something. + +Let me rewrite the first two +equations as 2x - lambda y = 0. + +And lambda x - 2y = 0. +And xy = 3. + +That is what we want to solve. +Well, I can put this into + +matrix form. +Two minus lambda, + +lambda minus two times x, +y equals 0,0. + +Now, how do I solve a linear +system matrix times x, + +y equals zero? +Well, I always have an obvious + +solution. +X and y both equal to zero. + +Is that a good solution? +No, because zero times zero is + +not three. +We want another solution, + +the trivial solution. +0,0 does not solve the + +constraint equation xy equals +three, so we want another + +solution. +When do we have another + +solution? +Well, when the determinant of a + +matrix is zero. +We have other solutions that + +exist only if determinant of a +matrix is zero. + +M is this guy. +Let's compute the determinant. + +Well, that seems to be negative +four plus lambda squared. + +That is zero exactly when +lambda squared equals four, + +which is lambda is plus or +minus two. + +Already you see here it is a +the level of difficulty that is + +a little bit much for an exam +but perfectly fine for a problem + +set or for a beautiful lecture +like this one. + +How do we deal with -- Well, +we have two cases to look at. + +Lambda equals two or lambda +equals minus two. + +Let's start with lambda equals +two. + +If I set lambda equals two, +what does this equation become? + +Well, it becomes x equals y. +This one becomes y equals x. + +Well, they seem to be the same. +x equals y. + +And then the equation xy equals +three becomes, + +well, x squared equals three. +I have two solutions. + +One is x equals root three and, +therefore, y equals root three + +as well, or negative root three +and negative root three. + +Let's look at the other case. +If I set lambda equal to + +negative two then I get 2x +equals negative 2y. + +That means x equals negative y. +The second one, + +2y equals negative 2x. +That is y equals negative x. + +Well, that is the same thing. +And xy equals three becomes + +negative x squared equals three. +Can we solve that? + +No. +There are no solutions here. + +Now we have two candidate +points which are these two + +points, root three, +root three or negative root + +three, negative root three. +OK. + +Let's actually look at what we +have here. + +Maybe you cannot read the +coordinates, but the point that + +I have here is indeed root +three, root three. + +How do we see that lambda +equals two? + +Well, if you look at this +picture, the gradient of f, + +that is the blue vector, +is indeed twice the yellow + +vector, gradient g. +That is where you read the + +value of lambda. +And we have the other solution + +which is somewhere here. +Negative root three, + +negative root there. +And there, again, + +lambda equals two. +The two vectors are + +proportional by a factor of two. +Yes? + +No, solutions are not quite +guaranteed to be absolute minima + +or maxima. +They are guaranteed to be + +somehow critical points end of a +constraint. + +That means if you were able to +solve and eliminate the variable + +that would be a critical point. +When you have the same problem, + +as we have critical points, +are they maxima or minima? + +And the answer is, +well, we won't know until we + +check. +More questions? + +No. +Yes? + +What is a Lagrange multiplier? +Well, it is this number lambda + +that is called the multiplier +here. + +It is a multiplier because it +is what you have to multiply + +gradient of g by to get gradient +of f. + +It multiplies. + +Let's try to see why is this +method valid? + +Because so far I have shown you +pictures and have said see they + +are tangent. +But why is it that they have to + +be tangent in general? +Let's think about it. + +Let's say that we are at +constrained min or max. + +What that means is that if I +move on the level g equals + +constant then the value of f +should only increase or only + +decrease. +But it means, + +in particular, +to first order it will not + +change. +At an unconstrained min or max, + +partial derivatives are zero. +In this case, + +derivatives are zero only in +the allowed directions. + +And the allowed directions are +those that stay on the levels of + +this g equals constant. +In any direction along the + +level set g = c the rate of +change of f must be zero. + +That is what happens at minima +or maxima. + +Except here, +of course, we look only at the + +allowed directions. +Let's say the same thing in + +terms of directional +derivatives. + +That means for any direction +that is tangent to the + +constraint level g equal c, +we must have df over ds in the + +direction of u equals zero. +I will draw a picture. + +Let's say now I am in three +variables just to give you + +different examples. +Here I have a level surface g + +equals c. +I am at my point. + +And if I move in any direction +that is on the level surface, + +so I move in the direction u +tangent to the level surface, + +then the rate of change of f in +that direction should be zero. + +Now, remember what the formula +is for this guy. + +Well, we have seen that this +guy is actually radiant f dot u. + +That means any such vector u +must be perpendicular to the + +gradient of f. +That means that the gradient of + +f should be perpendicular to +anything that is tangent to this + +level. +That means the gradient of f + +should be perpendicular to the +level set. + +That is what we have shown. + +But we know another vector that +is also perpendicular to the + +level set of g. +That is the gradient of g. + +We conclude that the gradient +of f must be parallel to the + +gradient of g because both are +perpendicular to the level set + +of g. +I see confused faces, + +so let me try to tell you again +where that comes from. + +We said if we had a constrained +minimum or maximum, + +if we move in the level set of +g, f doesn't change. + +Well, it doesn't change to +first order. + +It is the same idea as when you +are looking for a minimum you + +set the derivative equal to +zero. + +So the derivative in any +direction, tangent to g equals + +c, should be the directional +derivative of f, + +in any such direction, +should be zero. + +That is what we mean by +critical point of f. + +And so that means that any +vector u, any unit vector + +tangent to the level set of g is +going to be perpendicular to the + +gradient of f. +That means that the gradient of + +f is perpendicular to the level +set of g. + +If you want, +that means the level sets of f + +and g are tangent to each other. +That is justifying what we have + +observed in the picture that the +two level sets have to be + +tangent to each other at the +prime minimum or maximum. + +Does that make a little bit of +sense? + +Kind of. +I see at least a few faces + +nodding so I take that to be a +positive answer. + +Since I have been asked by +several of you, + +how do I know if it is a +maximum or a minimum? + +Well, warning, +the method doesn't tell whether + +a solution is a minimum or a +maximum. + +How do we do it? +Well, more bad news. + +We cannot use the second +derivative test. + +And the reason for that is that +we care actually only about + +these specific directions that +are tangent to variable of g. + +And we don't want to bother to +try to define directional second + +derivatives. +Not to mention that actually it + +wouldn't work. +There is a criterion but it is + +much more complicated than that. +Basically, the answer for us is + +that we don't have a second +derivative test in this + +situation. +What are we left with? + +Well, we are just left with +comparing values. + +Say that in this problem you +found a point where f equals + +three, a point where f equals +nine, a point where f equals 15. + +Well, then probably the minimum +is the point where f equals + +three and the maximum is 15. +Actually, in this case, + +where we found minima, +these two points are tied for + +minimum. +What about the maximum? + +What is the maximum of f on the +hyperbola? + +Well, it is infinity because +the point can go as far as you + +want from the origin. +But the general idea is if we + +have a good reason to believe +that there should be a minimum, + +and it's not like at infinity +or something weird like that, + +then the minimum will be a +solution of the Lagrange + +multiplier equations. +We just look for all the + +solutions and then we choose the +one that gives us the lowest + +value. +Is that good enough? + +Let me actually write that down. + +To find the minimum or the +maximum, we compare values of f + +at the various solutions -- -- +to Lagrange multiplier + +equations. + +I should say also that +sometimes you can just conclude + +by thinking geometrically. +In this case, + +when it is asking you which +point is closest to the origin + +you can just see that your +answer is the correct one. + +Let's do an advanced example. +Advanced means that -- Well, + +this one I didn't actually dare +to put on top of the other + +problem sets. +Instead, I am going to do it. + +What is this going to be about? +We are going to look for a + +surface minimizing pyramid. +Let's say that we want to build + +a pyramid with a given +triangular base -- -- and a + +given volume. +Say that I have maybe in the x, + +y plane I am giving you some +triangle. + +And I am going to try to build +a pyramid. + +Of course, I can choose where +to put the top of a pyramid. + +This guy will end up being +behind now. + +And the constraint and the goal +is to minimize the total surface + +area. +The first time I taught this + +class, it was a few years ago, +was just before they built the + +Stata Center. +And then I used to motivate + +this problem by saying Frank +Gehry has gone crazy and has + +been given a triangular plot of +land he wants to put a pyramid. + +There needs to be the right +amount of volume so that you can + +put all the offices in there. +And he wants it to be, + +actually, covered in solid +gold. + +And because that is expensive, +the administration wants him to + +cut the costs a bit. +And so you have to minimize the + +total size so that it doesn't +cost too much. + +We will see if MIT comes up +with a triangular pyramid + +building. +Hopefully not. + +It could be our next dorm, +you never know. + +Anyway, it is a fine geometry +problem. + +Let's try to think about how we +can do this. + +The natural way to think about +it would be -- Well, + +what do we have to look for +first? + +We have to look for the +position of that top point. + +Remember we know that the +volume of a pyramid is one-third + +the area of base times height. +In fact, fixing the volume, + +knowing that we have fixed the +area of a base, + +means that we are fixing the +height of the pyramid. + +The height is completely fixed. +What we have to choose just is + +where do we put that top point? +Do we put it smack in the + +middle of a triangle or to a +side or even anywhere we want? + +Its z coordinate is fixed. +Let's call h the height. + +What we could do is something +like this. + +We say we have three points of +a base. + +Let's call them p1 at (x1, +y1,0); p2 at (x2, + +y2,0); p3 at (x3, +y3,0). + +This point p is the unknown +point at (x, y, + +h). +We know the height. + +And then we want to minimize +the sum of the areas of these + +three triangles. +One here, one here and one at + +the back. +And areas of triangles we know + +how to express by using length +of cross-product. + +It becomes a function of x and +y. + +And you can try to minimize it. +Actually, it doesn't quite work. + +The formulas are just too +complicated. + +You will never get there. +What happens is actually maybe + +we need better coordinates. +Why do we need better + +coordinates? +That is because the geometry is + +kind of difficult to do if you +use x, y coordinates. + +I mean formula for +cross-product is fine, + +but then the length of the +vector will be annoying and just + +doesn't look good. +Instead, let's think about it + +differently. + +I claim if we do it this way +and we express the area as a + +function of x, +y, well, actually we can't + +solve for a minimum. +Here is another way to do it. + +Well, what has worked pretty +well for us so far is this + +geometric idea of base times +height. + +So let's think in terms of the +heights of side triangles. + +I am going to use the height of +these things. + +And I am going to say that the +area will be the sum of three + +terms, which are three bases +times three heights. + +Let's give names to these +quantities. + +Actually, for that it is going +to be good to have the point in + +the xy plane that lives directly +below p. + +Let's call it q. +P is the point that coordinates + +x, y, h. +And let's call q the point that + +is just below it and so it' +coordinates are x, + +y, 0. +Let's see. + +Let me draw a map of this thing. +p1, p2, p3 and I have my point + +q in the middle. +Let's see. + +To know these areas, +I need to know the base. + +Well, the base I can decide +that I know it because it is + +part of my given data. +I know the sides of this + +triangle. +Let me call the lengths a1, + +a2, a3. +I also need to know the height, + +so I need to know these +lengths. + +How do I know these lengths? +Well, its distance in space, + +but it is a little bit +annoying. + +But maybe I can reduce it to a +distance in the plane by looking + +instead at this distance here. +Let me give names to the + +distances from q to the sides. +Let's call u1, + +u2, u3 the distances from q to +the sides. + +Well, now I can claim I can +find, actually, + +sorry. +I need to draw one more thing. + +I claim I have a nice formula +for the area, + +because this is vertical and +this is horizontal so this + +length here is u3, +this length here is h. + +So what is this length here? +It is the square root of u3 + +squared plus h squared. +And similarly for these other + +guys. +They are square roots of a u + +squared plus h squared. +The heights of the faces are + +square root of u1 squared times +h squared. + +And similarly with u2 and u3. +So the total side area is going + +to be the area of the first +faces, + +one-half of base times height, +plus one-half of a base times a + +height plus one-half of the +third one. + +It doesn't look so much better. +But, trust me, + +it will get better. +Now, that is a function of + +three variables, +u1, u2, u3. + +And how do we relate u1, +u2, u3 to each other? + +They are probably not +independent. + +Well, let's cut this triangle +here into three pieces like + +that. +Then each piece has side -- + +Well, let's look at it the piece +of the bottom. + +It has base a3, height u3. +Cutting base into three tells + +you that the area of a base is +one-half of a1, + +u1 plus one-half of a2, +u2 plus one-half of a3, + +u3. +And that is our constraint. + +My three variables, +u1, u2, u3, are constrained in + +this way. +The sum of this figure must be + +the area of a base. +And I want to minimize that guy. + +So that is my g and that guy +here is my f. + +Now we try to apply our +Lagrange multiplier equations. + +Well, partial f of a partial u1 +is -- Well, + +if you do the calculation, +you will see it is one-half a1, + +u1 over square root of u1^2 +plus h^2 equals lambda, + +what is partial g, +partial a1? + +That one you can do, I am sure. +It is one-half a1. + +Oh, these guys simplify. +If you do the same with the + +second one -- -- things simplify +again. + +And the same with the third one. +Well, you will get, + +after simplifying, +u3 over square root of u3 + +squared plus h squared equals +lambda. + +Now, that means this guy equals +this guy equals this guy. + +They are all equal to lambda. +And, if you think about it, + +that means that u1 = u2 = u3. +See, it looked like scary + +equations but the solution is +very simple. + +What does it mean? +It means that our point q + +should be equidistant from all +three sides. + +That is called the incenter. +Q should be in the incenter. + +The next time you have to build +a golden pyramid and don't want + +to go broke, well, +you know where to put the top. + +If that was a bit fast, sorry. +Anyway, it is not completely + +crucial. +But go over it and you will see + +it works. +Have a nice weekend. \ No newline at end of file diff --git a/1El4znkRH0g.txt b/1El4znkRH0g.txt new file mode 100644 index 0000000000000000000000000000000000000000..303fbec86a2fc68e22778cf63578e50c36242712 --- /dev/null +++ b/1El4znkRH0g.txt @@ -0,0 +1,7131 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT OpenCourseWare continue to + + align:start position:0% +will help MIT OpenCourseWare continue to + + + align:start position:0% +will help MIT OpenCourseWare continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or view additional + + align:start position:0% +to make a donation or view additional + + + align:start position:0% +to make a donation or view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +so hello and welcome as I mentioned last + + align:start position:0% +so hello and welcome as I mentioned last + + + align:start position:0% +so hello and welcome as I mentioned last +time we're essentially done with the + + align:start position:0% +time we're essentially done with the + + + align:start position:0% +time we're essentially done with the +course we've done all the theoretical + + align:start position:0% +course we've done all the theoretical + + + align:start position:0% +course we've done all the theoretical +underpinnings what remains is to talk + + align:start position:0% +underpinnings what remains is to talk + + + align:start position:0% +underpinnings what remains is to talk +about two important applications of four + + align:start position:0% +about two important applications of four + + + align:start position:0% +about two important applications of four +yang in fact some some applications that + + align:start position:0% +yang in fact some some applications that + + + align:start position:0% +yang in fact some some applications that +are very difficult to do if we didn't + + align:start position:0% +are very difficult to do if we didn't + + + align:start position:0% +are very difficult to do if we didn't +have Fourier analysis and in fact quite + + align:start position:0% +have Fourier analysis and in fact quite + + + align:start position:0% +have Fourier analysis and in fact quite +simple to think about once we have + + align:start position:0% +simple to think about once we have + + + align:start position:0% +simple to think about once we have +Fourier analysis so today I'm going to + + align:start position:0% +Fourier analysis so today I'm going to + + + align:start position:0% +Fourier analysis so today I'm going to +talk about sampling we'll spend this + + align:start position:0% +talk about sampling we'll spend this + + + align:start position:0% +talk about sampling we'll spend this +lecture and the next lecture on sampling + + align:start position:0% +lecture and the next lecture on sampling + + + align:start position:0% +lecture and the next lecture on sampling +and then the following two lectures will + + align:start position:0% +and then the following two lectures will + + + align:start position:0% +and then the following two lectures will +be on modulation and we're done so we're + + align:start position:0% +be on modulation and we're done so we're + + + align:start position:0% +be on modulation and we're done so we're +almost done so we've talked about + + align:start position:0% +almost done so we've talked about + + + align:start position:0% +almost done so we've talked about +sampling lots in the past in fact it was + + align:start position:0% +sampling lots in the past in fact it was + + + align:start position:0% +sampling lots in the past in fact it was +on the very first homework that's in + + align:start position:0% +on the very first homework that's in + + + align:start position:0% +on the very first homework that's in +fact I think one of the strong points of + + align:start position:0% +fact I think one of the strong points of + + + align:start position:0% +fact I think one of the strong points of +this course is that we regard + + align:start position:0% +this course is that we regard + + + align:start position:0% +this course is that we regard +continuous-time signals and + + align:start position:0% +continuous-time signals and + + + align:start position:0% +continuous-time signals and +discrete-time signals on equal footing + + align:start position:0% +discrete-time signals on equal footing + + + align:start position:0% +discrete-time signals on equal footing +and part of the goal is to be very + + align:start position:0% +and part of the goal is to be very + + + align:start position:0% +and part of the goal is to be very +comfortable to convert back and forth + + align:start position:0% +comfortable to convert back and forth + + + align:start position:0% +comfortable to convert back and forth +because both representations are so + + align:start position:0% +because both representations are so + + + align:start position:0% +because both representations are so +important we see sig we see CT coming up + + align:start position:0% +important we see sig we see CT coming up + + + align:start position:0% +important we see sig we see CT coming up +in fundamental ways because a lot of the + + align:start position:0% +in fundamental ways because a lot of the + + + align:start position:0% +in fundamental ways because a lot of the +things that we're interested in our + + align:start position:0% +things that we're interested in our + + + align:start position:0% +things that we're interested in our +systems based on physics and that's just + + align:start position:0% +systems based on physics and that's just + + + align:start position:0% +systems based on physics and that's just +the way it is physics works in + + align:start position:0% +the way it is physics works in + + + align:start position:0% +the way it is physics works in +continuous time by and large + + align:start position:0% +continuous time by and large + + + align:start position:0% +continuous time by and large +however because of digital electronics + + align:start position:0% +however because of digital electronics + + + align:start position:0% +however because of digital electronics +we like to process things with elect + + align:start position:0% +we like to process things with elect + + + align:start position:0% +we like to process things with elect +with digital electronics because it's so + + align:start position:0% +with digital electronics because it's so + + + align:start position:0% +with digital electronics because it's so +inexpensive so for that reason we want + + align:start position:0% +inexpensive so for that reason we want + + + align:start position:0% +inexpensive so for that reason we want +to go back and forth and what we'll see + + align:start position:0% +to go back and forth and what we'll see + + + align:start position:0% +to go back and forth and what we'll see +today is that when we think about system + + align:start position:0% +today is that when we think about system + + + align:start position:0% +today is that when we think about system +levels when we think about signal level + + align:start position:0% +levels when we think about signal level + + + align:start position:0% +levels when we think about signal level +conversion Fourier transforms the keys + + align:start position:0% +conversion Fourier transforms the keys + + + align:start position:0% +conversion Fourier transforms the keys +so keep in mind we've already thought + + align:start position:0% +so keep in mind we've already thought + + + align:start position:0% +so keep in mind we've already thought +about how you would convert a CT system + + align:start position:0% +about how you would convert a CT system + + + align:start position:0% +about how you would convert a CT system +into a DT representation we did that + + align:start position:0% +into a DT representation we did that + + + align:start position:0% +into a DT representation we did that +back in about homework three or so so + + align:start position:0% +back in about homework three or so so + + + align:start position:0% +back in about homework three or so so +what's special today is thinking about + + align:start position:0% +what's special today is thinking about + + + align:start position:0% +what's special today is thinking about +rather than thinking about systems + + align:start position:0% +rather than thinking about systems + + + align:start position:0% +rather than thinking about systems +thinking about signals and there's as + + align:start position:0% +thinking about signals and there's as + + + align:start position:0% +thinking about signals and there's as +you can imagine there's enormous reasons + + align:start position:0% +you can imagine there's enormous reasons + + + align:start position:0% +you can imagine there's enormous reasons +why you would want to think about + + align:start position:0% +why you would want to think about + + + align:start position:0% +why you would want to think about +signals from a digital point of view + + align:start position:0% +signals from a digital point of view + + + align:start position:0% +signals from a digital point of view +virtually all the things that you play + + align:start position:0% +virtually all the things that you play + + + align:start position:0% +virtually all the things that you play +with all the time are digital so you + + align:start position:0% +with all the time are digital so you + + + align:start position:0% +with all the time are digital so you +think about audio signals they're now + + align:start position:0% +think about audio signals they're now + + + align:start position:0% +think about audio signals they're now +stored digitally + + align:start position:0% +stored digitally + + + align:start position:0% +stored digitally +I think about pictures digital video + + align:start position:0% +I think about pictures digital video + + + align:start position:0% +I think about pictures digital video +digital everything on the web because + + align:start position:0% +digital everything on the web because + + + align:start position:0% +digital everything on the web because +there's no other way the web can work if + + align:start position:0% +there's no other way the web can work if + + + align:start position:0% +there's no other way the web can work if +it's on the web it's digital so there's + + align:start position:0% +it's on the web it's digital so there's + + + align:start position:0% +it's on the web it's digital so there's +just an enormous reason why we would + + align:start position:0% +just an enormous reason why we would + + + align:start position:0% +just an enormous reason why we would +like to understand how to take a + + align:start position:0% +like to understand how to take a + + + align:start position:0% +like to understand how to take a +continuous time signal and turn it into + + align:start position:0% +continuous time signal and turn it into + + + align:start position:0% +continuous time signal and turn it into +a discrete representation this is just + + align:start position:0% +a discrete representation this is just + + + align:start position:0% +a discrete representation this is just +motivation we tend to think about common + + align:start position:0% +motivation we tend to think about common + + + align:start position:0% +motivation we tend to think about common +signals that we deal with every day as + + align:start position:0% +signals that we deal with every day as + + + align:start position:0% +signals that we deal with every day as +though they were in continuous time + + align:start position:0% +though they were in continuous time + + + align:start position:0% +though they were in continuous time +continuous space same thing we think + + align:start position:0% +continuous space same thing we think + + + align:start position:0% +continuous space same thing we think +about things like pictures as though + + align:start position:0% +about things like pictures as though + + + align:start position:0% +about things like pictures as though +they were continuous they aren't anybody + + align:start position:0% +they were continuous they aren't anybody + + + align:start position:0% +they were continuous they aren't anybody +who has a digital camera knows that if + + align:start position:0% +who has a digital camera knows that if + + + align:start position:0% +who has a digital camera knows that if +you zoom in enough you see individual + + align:start position:0% +you zoom in enough you see individual + + + align:start position:0% +you zoom in enough you see individual +pixels they are not continuous + + align:start position:0% +pixels they are not continuous + + + align:start position:0% +pixels they are not continuous +representations or discrete + + align:start position:0% +representations or discrete + + + align:start position:0% +representations or discrete +representations even some kinds of + + align:start position:0% +representations even some kinds of + + + align:start position:0% +representations even some kinds of +pictures that are ancient while ancient + + align:start position:0% +pictures that are ancient while ancient + + + align:start position:0% +pictures that are ancient while ancient +from Europe by your standards at least + + align:start position:0% +from Europe by your standards at least + + + align:start position:0% +from Europe by your standards at least +even well-known kinds of pictures like + + align:start position:0% +even well-known kinds of pictures like + + + align:start position:0% +even well-known kinds of pictures like +newsprint are in an underlying sense + + align:start position:0% +newsprint are in an underlying sense + + + align:start position:0% +newsprint are in an underlying sense +they are a discrete representation so + + align:start position:0% +they are a discrete representation so + + + align:start position:0% +they are a discrete representation so +what's showed here is a picture of a + + align:start position:0% +what's showed here is a picture of a + + + align:start position:0% +what's showed here is a picture of a +rose and a halftone image of the type + + align:start position:0% +rose and a halftone image of the type + + + align:start position:0% +rose and a halftone image of the type +that would be printed in a newspaper and + + align:start position:0% +that would be printed in a newspaper and + + + align:start position:0% +that would be printed in a newspaper and +if you zoom in you can see that this so + + align:start position:0% +if you zoom in you can see that this so + + + align:start position:0% +if you zoom in you can see that this so +if you zoom into this square so that you + + align:start position:0% +if you zoom into this square so that you + + + align:start position:0% +if you zoom into this square so that you +can see this better this which is not + + align:start position:0% +can see this better this which is not + + + align:start position:0% +can see this better this which is not +really continuous right I'm showing it + + align:start position:0% +really continuous right I'm showing it + + + align:start position:0% +really continuous right I'm showing it +on a digital projector it's actually got + + align:start position:0% +on a digital projector it's actually got + + + align:start position:0% +on a digital projector it's actually got +pixels too but the pixels are small + + align:start position:0% +pixels too but the pixels are small + + + align:start position:0% +pixels too but the pixels are small +enough for the time being I'm going to + + align:start position:0% +enough for the time being I'm going to + + + align:start position:0% +enough for the time being I'm going to +ignore that so consider this continuous + + align:start position:0% +ignore that so consider this continuous + + + align:start position:0% +ignore that so consider this continuous +even though it isn't and you can see the + + align:start position:0% +even though it isn't and you can see the + + + align:start position:0% +even though it isn't and you can see the +discrete nature of this one much more + + align:start position:0% +discrete nature of this one much more + + + align:start position:0% +discrete nature of this one much more +clearly in fact the halftone pictures + + align:start position:0% +clearly in fact the halftone pictures + + + align:start position:0% +clearly in fact the halftone pictures +that you see at a newspaper are not only + + align:start position:0% +that you see at a newspaper are not only + + + align:start position:0% +that you see at a newspaper are not only +discrete in time in space but they're + + align:start position:0% +discrete in time in space but they're + + + align:start position:0% +discrete in time in space but they're +discrete in amplitude because they're + + align:start position:0% +discrete in amplitude because they're + + + align:start position:0% +discrete in amplitude because they're +printed with ink ink comes in two + + align:start position:0% +printed with ink ink comes in two + + + align:start position:0% +printed with ink ink comes in two +flavors ink or knowing so they are a + + align:start position:0% +flavors ink or knowing so they are a + + + align:start position:0% +flavors ink or knowing so they are a +binary representation in intensity as + + align:start position:0% +binary representation in intensity as + + + align:start position:0% +binary representation in intensity as +well and we'll talk about that a little + + align:start position:0% +well and we'll talk about that a little + + + align:start position:0% +well and we'll talk about that a little +bit more in the next time so in order to + + align:start position:0% +bit more in the next time so in order to + + + align:start position:0% +bit more in the next time so in order to +have a complete digital representation + + align:start position:0% +have a complete digital representation + + + align:start position:0% +have a complete digital representation +you need to think about not only + + align:start position:0% +you need to think about not only + + + align:start position:0% +you need to think about not only +sampling in the time or here the space + + align:start position:0% +sampling in the time or here the space + + + align:start position:0% +sampling in the time or here the space +dimension but also sampling in the + + align:start position:0% +dimension but also sampling in the + + + align:start position:0% +dimension but also sampling in the +voltage or the amplitude dimensional + + align:start position:0% +voltage or the amplitude dimensional + + + align:start position:0% +voltage or the amplitude dimensional +even the highest resolution picture you + + align:start position:0% +even the highest resolution picture you + + + align:start position:0% +even the highest resolution picture you +have ever seen is digital so this refers + + align:start position:0% +have ever seen is digital so this refers + + + align:start position:0% +have ever seen is digital so this refers +to the completely ancient technology of + + align:start position:0% +to the completely ancient technology of + + + align:start position:0% +to the completely ancient technology of +how do you make a digital print so a + + align:start position:0% +how do you make a digital print so a + + + align:start position:0% +how do you make a digital print so a +very high quality picture is made from + + align:start position:0% +very high quality picture is made from + + + align:start position:0% +very high quality picture is made from +an emulsion of some sort of a chemical + + align:start position:0% +an emulsion of some sort of a chemical + + + align:start position:0% +an emulsion of some sort of a chemical +and originally silver bromide the idea + + align:start position:0% +and originally silver bromide the idea + + + align:start position:0% +and originally silver bromide the idea +was that you had very small crystals of + + align:start position:0% +was that you had very small crystals of + + + align:start position:0% +was that you had very small crystals of +silver bromide that could be reduced by + + align:start position:0% +silver bromide that could be reduced by + + + align:start position:0% +silver bromide that could be reduced by +a photon to turn them into silver metal + + align:start position:0% +a photon to turn them into silver metal + + + align:start position:0% +a photon to turn them into silver metal +and the idea was that exposure to light + + align:start position:0% +and the idea was that exposure to light + + + align:start position:0% +and the idea was that exposure to light +would therefore convert silver bromide + + align:start position:0% +would therefore convert silver bromide + + + align:start position:0% +would therefore convert silver bromide +the silver and then developing meant + + align:start position:0% +the silver and then developing meant + + + align:start position:0% +the silver and then developing meant +washing away the silver bromide salt + + align:start position:0% +washing away the silver bromide salt + + + align:start position:0% +washing away the silver bromide salt +that remained that was not converted + + align:start position:0% +that remained that was not converted + + + align:start position:0% +that remained that was not converted +leaving behind the silver that had and + + align:start position:0% +leaving behind the silver that had and + + + align:start position:0% +leaving behind the silver that had and +that was the basis for the chemical + + align:start position:0% +that was the basis for the chemical + + + align:start position:0% +that was the basis for the chemical +reaction that gave rise to pictures the + + align:start position:0% +reaction that gave rise to pictures the + + + align:start position:0% +reaction that gave rise to pictures the +point being that even there these + + align:start position:0% +point being that even there these + + + align:start position:0% +point being that even there these +crystals are on the order of a micron in + + align:start position:0% +crystals are on the order of a micron in + + + align:start position:0% +crystals are on the order of a micron in +size and they're either on or off so + + align:start position:0% +size and they're either on or off so + + + align:start position:0% +size and they're either on or off so +even there it was a sampled version and + + align:start position:0% +even there it was a sampled version and + + + align:start position:0% +even there it was a sampled version and +if it weren't enough everything you've + + align:start position:0% +if it weren't enough everything you've + + + align:start position:0% +if it weren't enough everything you've +ever seen is sampled because that's the + + align:start position:0% +ever seen is sampled because that's the + + + align:start position:0% +ever seen is sampled because that's the +way your eye works your eye has + + align:start position:0% +way your eye works your eye has + + + align:start position:0% +way your eye works your eye has +individual cells that either respond to + + align:start position:0% +individual cells that either respond to + + + align:start position:0% +individual cells that either respond to +light or don't there's about 100 million + + align:start position:0% +light or don't there's about 100 million + + + align:start position:0% +light or don't there's about 100 million +rods about 6 million cones so every + + align:start position:0% +rods about 6 million cones so every + + + align:start position:0% +rods about 6 million cones so every +image you have ever seen is sampled so + + align:start position:0% +image you have ever seen is sampled so + + + align:start position:0% +image you have ever seen is sampled so +one question is and you know it's such a + + align:start position:0% +one question is and you know it's such a + + + align:start position:0% +one question is and you know it's such a +good sampling that you don't even notice + + align:start position:0% +good sampling that you don't even notice + + + align:start position:0% +good sampling that you don't even notice +but maybe that's because you're well + + align:start position:0% +but maybe that's because you're well + + + align:start position:0% +but maybe that's because you're well +unaware to be polite so that so so the + + align:start position:0% +unaware to be polite so that so so the + + + align:start position:0% +unaware to be polite so that so so the +thing about how well sampled is it so I + + align:start position:0% +thing about how well sampled is it so I + + + align:start position:0% +thing about how well sampled is it so I +know that this picture is sampled + + align:start position:0% +know that this picture is sampled + + + align:start position:0% +know that this picture is sampled +because I can come up and I can see the + + align:start position:0% +because I can come up and I can see the + + + align:start position:0% +because I can come up and I can see the +individual pixels I can see a little + + align:start position:0% +individual pixels I can see a little + + + align:start position:0% +individual pixels I can see a little +grid of pixels + + align:start position:0% +grid of pixels + + + align:start position:0% +grid of pixels +there's 1024 by 768 I want you to think + + align:start position:0% +there's 1024 by 768 I want you to think + + + align:start position:0% +there's 1024 by 768 I want you to think +about how well your eye is sampling that + + align:start position:0% +about how well your eye is sampling that + + + align:start position:0% +about how well your eye is sampling that +by thinking about whether or not you + + align:start position:0% +by thinking about whether or not you + + + align:start position:0% +by thinking about whether or not you +should be able to see the pixels from + + align:start position:0% +should be able to see the pixels from + + + align:start position:0% +should be able to see the pixels from +where you're sitting + + align:start position:0% + + + + align:start position:0% + +based on the sampling this in your + + align:start position:0% +based on the sampling this in your + + + align:start position:0% +based on the sampling this in your +retina okay so look at your neighbor say + + align:start position:0% +retina okay so look at your neighbor say + + + align:start position:0% +retina okay so look at your neighbor say +hi figure out whether you have enough + + align:start position:0% +hi figure out whether you have enough + + + align:start position:0% +hi figure out whether you have enough +rods and cones to see individual pixels + + align:start position:0% +rods and cones to see individual pixels + + + align:start position:0% +rods and cones to see individual pixels +or not + + align:start position:0% + + + + align:start position:0% + +okay does anybody have a cow who can + + align:start position:0% +okay does anybody have a cow who can + + + align:start position:0% +okay does anybody have a cow who can +tell me a way to think about this or who + + align:start position:0% +tell me a way to think about this or who + + + align:start position:0% +tell me a way to think about this or who +can help me the answer do you have + + align:start position:0% +can help me the answer do you have + + + align:start position:0% +can help me the answer do you have +enough rods and cones to sample the + + align:start position:0% +enough rods and cones to sample the + + + align:start position:0% +enough rods and cones to sample the +pixels on the screen yes no but you + + align:start position:0% +pixels on the screen yes no but you + + + align:start position:0% +pixels on the screen yes no but you +can't you cannot okay well that could be + + align:start position:0% +can't you cannot okay well that could be + + + align:start position:0% +can't you cannot okay well that could be +because you don't have enough rods and + + align:start position:0% +because you don't have enough rods and + + + align:start position:0% +because you don't have enough rods and +cones a class astigmatism is that a rod + + align:start position:0% +cones a class astigmatism is that a rod + + + align:start position:0% +cones a class astigmatism is that a rod +and cone problem that's a lens problem + + align:start position:0% +and cone problem that's a lens problem + + + align:start position:0% +and cone problem that's a lens problem +so maybe you have enough rods and cones + + align:start position:0% +so maybe you have enough rods and cones + + + align:start position:0% +so maybe you have enough rods and cones +and not enough lens there's actually + + align:start position:0% +and not enough lens there's actually + + + align:start position:0% +and not enough lens there's actually +another reason you might not be able to + + align:start position:0% +another reason you might not be able to + + + align:start position:0% +another reason you might not be able to +do it besides rods cones and lenses + + align:start position:0% + + + + align:start position:0% + +brain there's even another one okay + + align:start position:0% +brain there's even another one okay + + + align:start position:0% +brain there's even another one okay +we're up there another reason why you + + align:start position:0% +we're up there another reason why you + + + align:start position:0% +we're up there another reason why you +might let me not be able to do it + + align:start position:0% + + + + align:start position:0% + +rods cones lenses brains photons that's + + align:start position:0% +rods cones lenses brains photons that's + + + align:start position:0% +rods cones lenses brains photons that's +an interesting thought I think you could + + align:start position:0% +an interesting thought I think you could + + + align:start position:0% +an interesting thought I think you could +probably pull that off yeah the number + + align:start position:0% +probably pull that off yeah the number + + + align:start position:0% +probably pull that off yeah the number +of photons if the lighting were low + + align:start position:0% +of photons if the lighting were low + + + align:start position:0% +of photons if the lighting were low +enough your eyes are very sensitive you + + align:start position:0% +enough your eyes are very sensitive you + + + align:start position:0% +enough your eyes are very sensitive you +can see you can see you can report a + + align:start position:0% +can see you can see you can report a + + + align:start position:0% +can see you can see you can report a +difference with one photon one it's + + align:start position:0% +difference with one photon one it's + + + align:start position:0% +difference with one photon one it's +pretty little it's kind of a limit right + + align:start position:0% +pretty little it's kind of a limit right + + + align:start position:0% +pretty little it's kind of a limit right +yeah it's so far away that you can't see + + align:start position:0% +yeah it's so far away that you can't see + + + align:start position:0% +yeah it's so far away that you can't see +the pixels but why is it because you + + align:start position:0% +the pixels but why is it because you + + + align:start position:0% +the pixels but why is it because you +don't have enough rosin cones because + + align:start position:0% +don't have enough rosin cones because + + + align:start position:0% +don't have enough rosin cones because +your lenses are screwed up so you might + + align:start position:0% +your lenses are screwed up so you might + + + align:start position:0% +your lenses are screwed up so you might +be using your rods and cones for + + align:start position:0% +be using your rods and cones for + + + align:start position:0% +be using your rods and cones for +different things you're right your cones + + align:start position:0% +different things you're right your cones + + + align:start position:0% +different things you're right your cones +are focused in an area called the fovea + + align:start position:0% +are focused in an area called the fovea + + + align:start position:0% +are focused in an area called the fovea +right so one way you could improve that + + align:start position:0% +right so one way you could improve that + + + align:start position:0% +right so one way you could improve that +would be to look at it can somebody + + align:start position:0% +would be to look at it can somebody + + + align:start position:0% +would be to look at it can somebody +think of something besides rods cones + + align:start position:0% +think of something besides rods cones + + + align:start position:0% +think of something besides rods cones +lenses and brains can somebody think of + + align:start position:0% +lenses and brains can somebody think of + + + align:start position:0% +lenses and brains can somebody think of +convolution lecturer with some sort of + + align:start position:0% +convolution lecturer with some sort of + + + align:start position:0% +convolution lecturer with some sort of +application that we did in convolution + + align:start position:0% +application that we did in convolution + + + align:start position:0% +application that we did in convolution +no of course not that was more than ten + + align:start position:0% +no of course not that was more than ten + + + align:start position:0% +no of course not that was more than ten +lectures ago in convolution we looked at + + align:start position:0% +lectures ago in convolution we looked at + + + align:start position:0% +lectures ago in convolution we looked at +the Hubble Space Telescope + + align:start position:0% +the Hubble Space Telescope + + + align:start position:0% +the Hubble Space Telescope +and we looked at a microscope yes + + align:start position:0% + + + + align:start position:0% + +particles in the air that was something + + align:start position:0% +particles in the air that was something + + + align:start position:0% +particles in the air that was something +that happened in in Hubble so + + align:start position:0% +that happened in in Hubble so + + + align:start position:0% +that happened in in Hubble so +smoke-filled rooms that's bad there's + + align:start position:0% +smoke-filled rooms that's bad there's + + + align:start position:0% +smoke-filled rooms that's bad there's +something from the Hubble experiment + + align:start position:0% +something from the Hubble experiment + + + align:start position:0% +something from the Hubble experiment +from the Hubble lecture we talked about + + align:start position:0% +from the Hubble lecture we talked about + + + align:start position:0% +from the Hubble lecture we talked about +how there was a point spread function + + align:start position:0% +how there was a point spread function + + + align:start position:0% +how there was a point spread function +associated with diffraction and there's + + align:start position:0% +associated with diffraction and there's + + + align:start position:0% +associated with diffraction and there's +also a diffraction limit besides because + + align:start position:0% +also a diffraction limit besides because + + + align:start position:0% +also a diffraction limit besides because +of the size of you poop pupil okay + + align:start position:0% +of the size of you poop pupil okay + + + align:start position:0% +of the size of you poop pupil okay +because you're looking through a narrow + + align:start position:0% +because you're looking through a narrow + + + align:start position:0% +because you're looking through a narrow +aperture that limits the resolution as + + align:start position:0% +aperture that limits the resolution as + + + align:start position:0% +aperture that limits the resolution as +well but let's get back to this Ronson + + align:start position:0% +well but let's get back to this Ronson + + + align:start position:0% +well but let's get back to this Ronson +coat you have enough rods and cones how + + align:start position:0% +coat you have enough rods and cones how + + + align:start position:0% +coat you have enough rods and cones how +do you do that how do you think about + + align:start position:0% +do you do that how do you think about + + + align:start position:0% +do you do that how do you think about +whether you have enough rods and cones + + align:start position:0% +whether you have enough rods and cones + + + align:start position:0% +whether you have enough rods and cones +okay step one look at the previous slide + + align:start position:0% +okay step one look at the previous slide + + + align:start position:0% +okay step one look at the previous slide +what was the important thing on the + + align:start position:0% +what was the important thing on the + + + align:start position:0% +what was the important thing on the +previous slide three microns per rod and + + align:start position:0% +previous slide three microns per rod and + + + align:start position:0% +previous slide three microns per rod and +cone right so rising cones are separated + + align:start position:0% +cone right so rising cones are separated + + + align:start position:0% +cone right so rising cones are separated +by three microns so how what do I do + + align:start position:0% +by three microns so how what do I do + + + align:start position:0% +by three microns so how what do I do +with that how do I compare rods and + + align:start position:0% +with that how do I compare rods and + + + align:start position:0% +with that how do I compare rods and +cones three microns to this anybody + + align:start position:0% +cones three microns to this anybody + + + align:start position:0% +cones three microns to this anybody +remember anything about optics so I have + + align:start position:0% +remember anything about optics so I have + + + align:start position:0% +remember anything about optics so I have +this big lens right and we have the eye + + align:start position:0% +this big lens right and we have the eye + + + align:start position:0% +this big lens right and we have the eye +on one side and we have the object on + + align:start position:0% +on one side and we have the object on + + + align:start position:0% +on one side and we have the object on +the other side and we need to map some + + align:start position:0% +the other side and we need to map some + + + align:start position:0% +the other side and we need to map some +retina over here to some screen over + + align:start position:0% +retina over here to some screen over + + + align:start position:0% +retina over here to some screen over +here what's the important to do what's + + align:start position:0% +here what's the important to do what's + + + align:start position:0% +here what's the important to do what's +the important thing to do in the Mac oh + + align:start position:0% + + + + align:start position:0% + +come on Joe remember going to high + + align:start position:0% +come on Joe remember going to high + + + align:start position:0% +come on Joe remember going to high +school No + + align:start position:0% +school No + + + align:start position:0% +school No +okay so if you have a lens right rays go + + align:start position:0% +okay so if you have a lens right rays go + + + align:start position:0% +okay so if you have a lens right rays go +straight through the lens without being + + align:start position:0% +straight through the lens without being + + + align:start position:0% +straight through the lens without being +bent right that's why the rules for + + align:start position:0% +bent right that's why the rules for + + + align:start position:0% +bent right that's why the rules for +lenses so that is enough information + + align:start position:0% +lenses so that is enough information + + + align:start position:0% +lenses so that is enough information +actually to tell us the map the map + + align:start position:0% +actually to tell us the map the map + + + align:start position:0% +actually to tell us the map the map +three lenses so as to preserve angles so + + align:start position:0% +three lenses so as to preserve angles so + + + align:start position:0% +three lenses so as to preserve angles so +if we figure out how closely spaced are + + align:start position:0% +if we figure out how closely spaced are + + + align:start position:0% +if we figure out how closely spaced are +the rods and cones on this side that'll + + align:start position:0% +the rods and cones on this side that'll + + + align:start position:0% +the rods and cones on this side that'll +give me some angle that I can resolve + + align:start position:0% +give me some angle that I can resolve + + + align:start position:0% +give me some angle that I can resolve +and the question is whether that's angle + + align:start position:0% +and the question is whether that's angle + + + align:start position:0% +and the question is whether that's angle +is bigger or smaller than the angle + + align:start position:0% +is bigger or smaller than the angle + + + align:start position:0% +is bigger or smaller than the angle +that's required to resolve pixels okay + + align:start position:0% +that's required to resolve pixels okay + + + align:start position:0% +that's required to resolve pixels okay +so the angle so if we make a small angle + + align:start position:0% +so the angle so if we make a small angle + + + align:start position:0% +so the angle so if we make a small angle +approximation say that theta is on the + + align:start position:0% +approximation say that theta is on the + + + align:start position:0% +approximation say that theta is on the +order of sine theta right then the + + align:start position:0% +order of sine theta right then the + + + align:start position:0% +order of sine theta right then the +spacing between these is like three + + align:start position:0% +spacing between these is like three + + + align:start position:0% +spacing between these is like three +micrometers the distance between the + + align:start position:0% +micrometers the distance between the + + + align:start position:0% +micrometers the distance between the +lens in your eye and the retina is on + + align:start position:0% +lens in your eye and the retina is on + + + align:start position:0% +lens in your eye and the retina is on +the order of say three centimeters + + align:start position:0% +the order of say three centimeters + + + align:start position:0% +the order of say three centimeters +something like that so that's the angle + + align:start position:0% +something like that so that's the angle + + + align:start position:0% +something like that so that's the angle +at your eye and the question is how does + + align:start position:0% +at your eye and the question is how does + + + align:start position:0% +at your eye and the question is how does +that compare to the angle at the screen + + align:start position:0% + + + + align:start position:0% + +right and so the screen this is like + + align:start position:0% +right and so the screen this is like + + + align:start position:0% +right and so the screen this is like +three meters but the pixels there's 1024 + + align:start position:0% +three meters but the pixels there's 1024 + + + align:start position:0% +three meters but the pixels there's 1024 +pixels in that range and this distance + + align:start position:0% +pixels in that range and this distance + + + align:start position:0% +pixels in that range and this distance +is like 10 meters something like that + + align:start position:0% +is like 10 meters something like that + + + align:start position:0% +is like 10 meters something like that +so the question is whether or not the + + align:start position:0% +so the question is whether or not the + + + align:start position:0% +so the question is whether or not the +angle subtended by the pixels is bigger + + align:start position:0% +angle subtended by the pixels is bigger + + + align:start position:0% +angle subtended by the pixels is bigger +or smaller than the angle subtended by + + align:start position:0% +or smaller than the angle subtended by + + + align:start position:0% +or smaller than the angle subtended by +the rods and cones right that's the + + align:start position:0% +the rods and cones right that's the + + + align:start position:0% +the rods and cones right that's the +issue and so if you work that out the + + align:start position:0% +issue and so if you work that out the + + + align:start position:0% +issue and so if you work that out the +angle between the rods and cones is on + + align:start position:0% +angle between the rods and cones is on + + + align:start position:0% +angle between the rods and cones is on +the order of 10 to the minus 4 Radian + + align:start position:0% +the order of 10 to the minus 4 Radian + + + align:start position:0% +the order of 10 to the minus 4 Radian +and the angle between pixels is on the + + align:start position:0% +and the angle between pixels is on the + + + align:start position:0% +and the angle between pixels is on the +order of 3 times that so got a couple of + + align:start position:0% +order of 3 times that so got a couple of + + + align:start position:0% +order of 3 times that so got a couple of +interesting things you have enough rods + + align:start position:0% +interesting things you have enough rods + + + align:start position:0% +interesting things you have enough rods +and cones to see it but only barely okay + + align:start position:0% +and cones to see it but only barely okay + + + align:start position:0% +and cones to see it but only barely okay +by a factor of 3 roughly I'm not + + align:start position:0% +by a factor of 3 roughly I'm not + + + align:start position:0% +by a factor of 3 roughly I'm not +worrying about the fovea right the fovea + + align:start position:0% +worrying about the fovea right the fovea + + + align:start position:0% +worrying about the fovea right the fovea +has more right so this is just a crude + + align:start position:0% +has more right so this is just a crude + + + align:start position:0% +has more right so this is just a crude +approximation I'm not worried about your + + align:start position:0% +approximation I'm not worried about your + + + align:start position:0% +approximation I'm not worried about your +eyeglasses + + align:start position:0% +eyeglasses + + + align:start position:0% +eyeglasses +but crudely speaking you have enough + + align:start position:0% +but crudely speaking you have enough + + + align:start position:0% +but crudely speaking you have enough +rods and cones to resolve the pixels and + + align:start position:0% +rods and cones to resolve the pixels and + + + align:start position:0% +rods and cones to resolve the pixels and +another factor of 3 or so which means + + align:start position:0% +another factor of 3 or so which means + + + align:start position:0% +another factor of 3 or so which means +for example that making a projector with + + align:start position:0% +for example that making a projector with + + + align:start position:0% +for example that making a projector with +3 by 3 times more pixels makes sense + + align:start position:0% +3 by 3 times more pixels makes sense + + + align:start position:0% +3 by 3 times more pixels makes sense +and making one that's got a hundred + + align:start position:0% +and making one that's got a hundred + + + align:start position:0% +and making one that's got a hundred +times 100 times more pixels doesn't ok + + align:start position:0% +times 100 times more pixels doesn't ok + + + align:start position:0% +times 100 times more pixels doesn't ok +and that's the kind of thing we'd like + + align:start position:0% +and that's the kind of thing we'd like + + + align:start position:0% +and that's the kind of thing we'd like +to work out when we're thinking about + + align:start position:0% +to work out when we're thinking about + + + align:start position:0% +to work out when we're thinking about +discrete representations for signals + + align:start position:0% +discrete representations for signals + + + align:start position:0% +discrete representations for signals +right how many samples do you need ok so + + align:start position:0% +right how many samples do you need ok so + + + align:start position:0% +right how many samples do you need ok so +what we'd like to do today is figure out + + align:start position:0% +what we'd like to do today is figure out + + + align:start position:0% +what we'd like to do today is figure out +how sampling affects the info + + align:start position:0% +how sampling affects the info + + + align:start position:0% +how sampling affects the info +that's contained in a signal we'd like + + align:start position:0% +that's contained in a signal we'd like + + + align:start position:0% +that's contained in a signal we'd like +to sample a signal so think about the + + align:start position:0% +to sample a signal so think about the + + + align:start position:0% +to sample a signal so think about the +blue signal here and think about the red + + align:start position:0% +blue signal here and think about the red + + + align:start position:0% +blue signal here and think about the red +samples + + align:start position:0% +samples + + + align:start position:0% +samples +we'd like to sample a signal in a way + + align:start position:0% +we'd like to sample a signal in a way + + + align:start position:0% +we'd like to sample a signal in a way +that we preserve all of the information + + align:start position:0% +that we preserve all of the information + + + align:start position:0% +that we preserve all of the information +about that signal and as you can see + + align:start position:0% +about that signal and as you can see + + + align:start position:0% +about that signal and as you can see +from the example that I picked it's not + + align:start position:0% +from the example that I picked it's not + + + align:start position:0% +from the example that I picked it's not +at all clear that you can do that in + + align:start position:0% +at all clear that you can do that in + + + align:start position:0% +at all clear that you can do that in +fact if you look at the bottom picture + + align:start position:0% +fact if you look at the bottom picture + + + align:start position:0% +fact if you look at the bottom picture +I've coerced two signals to follow on + + align:start position:0% +I've coerced two signals to follow on + + + align:start position:0% +I've coerced two signals to follow on +the same samples so the green signal is + + align:start position:0% +the same samples so the green signal is + + + align:start position:0% +the same samples so the green signal is +the co 7 pi n over 3 and the red signal + + align:start position:0% +the co 7 pi n over 3 and the red signal + + + align:start position:0% +the co 7 pi n over 3 and the red signal +is the co spy n over 3 and they go they + + align:start position:0% +is the co spy n over 3 and they go they + + + align:start position:0% +is the co spy n over 3 and they go they +all go through the same blue samples the + + align:start position:0% +all go through the same blue samples the + + + align:start position:0% +all go through the same blue samples the +same blue samples is shared by both of + + align:start position:0% +same blue samples is shared by both of + + + align:start position:0% +same blue samples is shared by both of +those signals so is patently obvious + + align:start position:0% +those signals so is patently obvious + + + align:start position:0% +those signals so is patently obvious +that I cannot uniquely reconstruct the + + align:start position:0% +that I cannot uniquely reconstruct the + + + align:start position:0% +that I cannot uniquely reconstruct the +signal from the samples that's + + align:start position:0% +signal from the samples that's + + + align:start position:0% +signal from the samples that's +absolutely clear right it's also clear + + align:start position:0% +absolutely clear right it's also clear + + + align:start position:0% +absolutely clear right it's also clear +by just thinking about the the the basic + + align:start position:0% +by just thinking about the the the basic + + + align:start position:0% +by just thinking about the the the basic +mathematics of signals a CT signal could + + align:start position:0% +mathematics of signals a CT signal could + + + align:start position:0% +mathematics of signals a CT signal could +move up and down arbitrarily between two + + align:start position:0% +move up and down arbitrarily between two + + + align:start position:0% +move up and down arbitrarily between two +samples how could you possibly learn + + align:start position:0% +samples how could you possibly learn + + + align:start position:0% +samples how could you possibly learn +information about what happened between + + align:start position:0% +information about what happened between + + + align:start position:0% +information about what happened between +the samples by looking just at the + + align:start position:0% +the samples by looking just at the + + + align:start position:0% +the samples by looking just at the +samples right so it's not at all clear + + align:start position:0% +samples right so it's not at all clear + + + align:start position:0% +samples right so it's not at all clear +that you're going to be able to do this + + align:start position:0% +that you're going to be able to do this + + + align:start position:0% +that you're going to be able to do this +so let's take the opposite tact which is + + align:start position:0% +so let's take the opposite tact which is + + + align:start position:0% +so let's take the opposite tact which is +to say let's assume I only have the + + align:start position:0% +to say let's assume I only have the + + + align:start position:0% +to say let's assume I only have the +samples what can I tell you about what + + align:start position:0% +samples what can I tell you about what + + + align:start position:0% +samples what can I tell you about what +the signal might have been what's the + + align:start position:0% +the signal might have been what's the + + + align:start position:0% +the signal might have been what's the +relationship between the samples and the + + align:start position:0% +relationship between the samples and the + + + align:start position:0% +relationship between the samples and the +signal and the way to think about that + + align:start position:0% +signal and the way to think about that + + + align:start position:0% +signal and the way to think about that +one way is the thing about something + + align:start position:0% +one way is the thing about something + + + align:start position:0% +one way is the thing about something +that we will call impulse reconstruction + + align:start position:0% +that we will call impulse reconstruction + + + align:start position:0% +that we will call impulse reconstruction +if I only had the samples what could I + + align:start position:0% +if I only had the samples what could I + + + align:start position:0% +if I only had the samples what could I +do to reproduce a CT signal the simplest + + align:start position:0% +do to reproduce a CT signal the simplest + + + align:start position:0% +do to reproduce a CT signal the simplest +thing I might conceive of doing is + + align:start position:0% +thing I might conceive of doing is + + + align:start position:0% +thing I might conceive of doing is +replace every sample with some nonzero + + align:start position:0% +replace every sample with some nonzero + + + align:start position:0% +replace every sample with some nonzero +component of the CT representation so I + + align:start position:0% +component of the CT representation so I + + + align:start position:0% +component of the CT representation so I +only have samples up here at n T so + + align:start position:0% +only have samples up here at n T so + + + align:start position:0% +only have samples up here at n T so +generate a new CT signal that contains + + align:start position:0% +generate a new CT signal that contains + + + align:start position:0% +generate a new CT signal that contains +the information in the samples that is + + align:start position:0% +the information in the samples that is + + + align:start position:0% +the information in the samples that is +to say X of N + + align:start position:0% +to say X of N + + + align:start position:0% +to say X of N +which means I only have an integer + + align:start position:0% +which means I only have an integer + + + align:start position:0% +which means I only have an integer +number of non zero elements in the CT + + align:start position:0% +number of non zero elements in the CT + + + align:start position:0% +number of non zero elements in the CT +representation so in order to make that + + align:start position:0% +representation so in order to make that + + + align:start position:0% +representation so in order to make that +signal have a nonzero integral the + + align:start position:0% +signal have a nonzero integral the + + + align:start position:0% +signal have a nonzero integral the +things I represent each sample with + + align:start position:0% +things I represent each sample with + + + align:start position:0% +things I represent each sample with +better be an impulse right otherwise I + + align:start position:0% +better be an impulse right otherwise I + + + align:start position:0% +better be an impulse right otherwise I +would have finitely many nonzero points + + align:start position:0% +would have finitely many nonzero points + + + align:start position:0% +would have finitely many nonzero points +in a finite time interval in the + + align:start position:0% +in a finite time interval in the + + + align:start position:0% +in a finite time interval in the +interval and the integral over the + + align:start position:0% +interval and the integral over the + + + align:start position:0% +interval and the integral over the +interval would be zero always right so I + + align:start position:0% +interval would be zero always right so I + + + align:start position:0% +interval would be zero always right so I +have to use impulses so the simplest + + align:start position:0% +have to use impulses so the simplest + + + align:start position:0% +have to use impulses so the simplest +thing I could do would be take every one + + align:start position:0% +thing I could do would be take every one + + + align:start position:0% +thing I could do would be take every one +of these samples and replace it by an + + align:start position:0% +of these samples and replace it by an + + + align:start position:0% +of these samples and replace it by an +impulse located at the right time so put + + align:start position:0% +impulse located at the right time so put + + + align:start position:0% +impulse located at the right time so put +the nth one at time T equals n cap T put + + align:start position:0% +the nth one at time T equals n cap T put + + + align:start position:0% +the nth one at time T equals n cap T put +it where the sample came from and scale + + align:start position:0% +it where the sample came from and scale + + + align:start position:0% +it where the sample came from and scale +the weight to be in proportion to the + + align:start position:0% +the weight to be in proportion to the + + + align:start position:0% +the weight to be in proportion to the +amplitude of X of n that's kind of the + + align:start position:0% +amplitude of X of n that's kind of the + + + align:start position:0% +amplitude of X of n that's kind of the +simplest thing I could possibly do + + align:start position:0% +simplest thing I could possibly do + + + align:start position:0% +simplest thing I could possibly do +that's called impulse reconstruction and + + align:start position:0% +that's called impulse reconstruction and + + + align:start position:0% +that's called impulse reconstruction and +then let's ask the question how does the + + align:start position:0% +then let's ask the question how does the + + + align:start position:0% +then let's ask the question how does the +X that I started with relate to this X P + + align:start position:0% +X that I started with relate to this X P + + + align:start position:0% +X that I started with relate to this X P +this impulse reconstruction thing that I + + align:start position:0% +this impulse reconstruction thing that I + + + align:start position:0% +this impulse reconstruction thing that I +just made and as you might imagine from + + align:start position:0% +just made and as you might imagine from + + + align:start position:0% +just made and as you might imagine from +the theory of lectures that relationship + + align:start position:0% +the theory of lectures that relationship + + + align:start position:0% +the theory of lectures that relationship +is going to be simple right so think + + align:start position:0% +is going to be simple right so think + + + align:start position:0% +is going to be simple right so think +about what what am i doing I'm trying to + + align:start position:0% +about what what am i doing I'm trying to + + + align:start position:0% +about what what am i doing I'm trying to +think about I started with X event I + + align:start position:0% +think about I started with X event I + + + align:start position:0% +think about I started with X event I +started with X of T sorry I turned that + + align:start position:0% +started with X of T sorry I turned that + + + align:start position:0% +started with X of T sorry I turned that +into samples I turned that into X P of T + + align:start position:0% +into samples I turned that into X P of T + + + align:start position:0% +into samples I turned that into X P of T +and now I'm trying to compare those two + + align:start position:0% +and now I'm trying to compare those two + + + align:start position:0% +and now I'm trying to compare those two +signals that's the game plan + + align:start position:0% +signals that's the game plan + + + align:start position:0% +signals that's the game plan +so think about X of P from the previous + + align:start position:0% +so think about X of P from the previous + + + align:start position:0% +so think about X of P from the previous +slide it's weighted impulses shifted in + + align:start position:0% +slide it's weighted impulses shifted in + + + align:start position:0% +slide it's weighted impulses shifted in +time to the appropriate place this X of + + align:start position:0% +time to the appropriate place this X of + + + align:start position:0% +time to the appropriate place this X of +n was was derived by uniform sampling of + + align:start position:0% +n was was derived by uniform sampling of + + + align:start position:0% +n was was derived by uniform sampling of +X of T so X of n was X of n T and since + + align:start position:0% +X of T so X of n was X of n T and since + + + align:start position:0% +X of T so X of n was X of n T and since +this impulse is 0 everywhere except + + align:start position:0% +this impulse is 0 everywhere except + + + align:start position:0% +this impulse is 0 everywhere except +where the argument is 0 it doesn't + + align:start position:0% +where the argument is 0 it doesn't + + + align:start position:0% +where the argument is 0 it doesn't +matter whether I call this thing NT or T + + align:start position:0% +matter whether I call this thing NT or T + + + align:start position:0% +matter whether I call this thing NT or T +the same thing because the impulse only + + align:start position:0% +the same thing because the impulse only + + + align:start position:0% +the same thing because the impulse only +looks at T equals NT so whether I call + + align:start position:0% +looks at T equals NT so whether I call + + + align:start position:0% +looks at T equals NT so whether I call +it n T or T is irrelevant if I call it T + + align:start position:0% +it n T or T is irrelevant if I call it T + + + align:start position:0% +it n T or T is irrelevant if I call it T +then this part has no N in it and I can + + align:start position:0% +then this part has no N in it and I can + + + align:start position:0% +then this part has no N in it and I can +factor it outside and I just get an + + align:start position:0% +factor it outside and I just get an + + + align:start position:0% +factor it outside and I just get an +impulse train and not too surprisingly X + + align:start position:0% +impulse train and not too surprisingly X + + + align:start position:0% +impulse train and not too surprisingly X +P is just the product this signal is + + align:start position:0% +P is just the product this signal is + + + align:start position:0% +P is just the product this signal is +just this signal multiplied by an + + align:start position:0% +just this signal multiplied by an + + + align:start position:0% +just this signal multiplied by an +impulse train okay so if I derive X P by + + align:start position:0% +impulse train okay so if I derive X P by + + + align:start position:0% +impulse train okay so if I derive X P by +multiplying by an impulse train your + + align:start position:0% +multiplying by an impulse train your + + + align:start position:0% +multiplying by an impulse train your +knee-jerk reaction is to say multiply by + + align:start position:0% +knee-jerk reaction is to say multiply by + + + align:start position:0% +knee-jerk reaction is to say multiply by +an impulse train + + align:start position:0% + + + + align:start position:0% + +sounds like a Fourier transform + + align:start position:0% +sounds like a Fourier transform + + + align:start position:0% +sounds like a Fourier transform +somewhere on if I multiply in time by an + + align:start position:0% +somewhere on if I multiply in time by an + + + align:start position:0% +somewhere on if I multiply in time by an +impulse train what do I do in Fourier + + align:start position:0% +impulse train what do I do in Fourier + + + align:start position:0% +impulse train what do I do in Fourier +transform land convolve right multiply + + align:start position:0% +transform land convolve right multiply + + + align:start position:0% +transform land convolve right multiply +in time convolve in frequency so if this + + align:start position:0% +in time convolve in frequency so if this + + + align:start position:0% +in time convolve in frequency so if this +was my original ax this thing if this is + + align:start position:0% +was my original ax this thing if this is + + + align:start position:0% +was my original ax this thing if this is +the transform of that thing and if this + + align:start position:0% +the transform of that thing and if this + + + align:start position:0% +the transform of that thing and if this +is the transform of my impulse train + + align:start position:0% +is the transform of my impulse train + + + align:start position:0% +is the transform of my impulse train +transform of an impulse train in time is + + align:start position:0% +transform of an impulse train in time is + + + align:start position:0% +transform of an impulse train in time is +an impulse train in frequency the the + + align:start position:0% +an impulse train in frequency the the + + + align:start position:0% +an impulse train in frequency the the +impulses in frequency are separated by + + align:start position:0% +impulses in frequency are separated by + + + align:start position:0% +impulses in frequency are separated by +Omega s equal to 2pi over T and the + + align:start position:0% +Omega s equal to 2pi over T and the + + + align:start position:0% +Omega s equal to 2pi over T and the +amplitude is equal to Omega s 2 PI over + + align:start position:0% +amplitude is equal to Omega s 2 PI over + + + align:start position:0% +amplitude is equal to Omega s 2 PI over +T so they're spaced and have an + + align:start position:0% +T so they're spaced and have an + + + align:start position:0% +T so they're spaced and have an +amplitude both the spacing and the + + align:start position:0% +amplitude both the spacing and the + + + align:start position:0% +amplitude both the spacing and the +amplitude or 2pi over T right and if I'm + + align:start position:0% +amplitude or 2pi over T right and if I'm + + + align:start position:0% +amplitude or 2pi over T right and if I'm +multiplying in time x times P I can + + align:start position:0% +multiplying in time x times P I can + + + align:start position:0% +multiplying in time x times P I can +volve in frequency so this is my answer + + align:start position:0% +volve in frequency so this is my answer + + + align:start position:0% +volve in frequency so this is my answer +what's the relationship between X and XP + + align:start position:0% +what's the relationship between X and XP + + + align:start position:0% +what's the relationship between X and XP +it's multiplied in time by an impulse + + align:start position:0% +it's multiplied in time by an impulse + + + align:start position:0% +it's multiplied in time by an impulse +train or its convolve din frequency with + + align:start position:0% +train or its convolve din frequency with + + + align:start position:0% +train or its convolve din frequency with +an impulse train so the answer how does + + align:start position:0% +an impulse train so the answer how does + + + align:start position:0% +an impulse train so the answer how does +XP relate to ax it looks very similar + + align:start position:0% +XP relate to ax it looks very similar + + + align:start position:0% +XP relate to ax it looks very similar +for some frequencies but there's a lot + + align:start position:0% +for some frequencies but there's a lot + + + align:start position:0% +for some frequencies but there's a lot +more frequencies okay not too surprising + + align:start position:0% +more frequencies okay not too surprising + + + align:start position:0% +more frequencies okay not too surprising +I multiplied by impulses impulses have + + align:start position:0% +I multiplied by impulses impulses have + + + align:start position:0% +I multiplied by impulses impulses have +all frequencies right so what I've done + + align:start position:0% +all frequencies right so what I've done + + + align:start position:0% +all frequencies right so what I've done +when I've sampled it if I think about + + align:start position:0% +when I've sampled it if I think about + + + align:start position:0% +when I've sampled it if I think about +the sampled signal being represented in + + align:start position:0% +the sampled signal being represented in + + + align:start position:0% +the sampled signal being represented in +CT as the multiplication by an infinite + + align:start position:0% +CT as the multiplication by an infinite + + + align:start position:0% +CT as the multiplication by an infinite +impulse train I've introduced new + + align:start position:0% +impulse train I've introduced new + + + align:start position:0% +impulse train I've introduced new +frequency components to the Fourier + + align:start position:0% +frequency components to the Fourier + + + align:start position:0% +frequency components to the Fourier +representation that's the main message + + align:start position:0% +representation that's the main message + + + align:start position:0% +representation that's the main message +this slide is today's lecture the way we + + align:start position:0% +this slide is today's lecture the way we + + + align:start position:0% +this slide is today's lecture the way we +can think about sampling in time is as + + align:start position:0% +can think about sampling in time is as + + + align:start position:0% +can think about sampling in time is as +convolution and frequency okay + + align:start position:0% +convolution and frequency okay + + + align:start position:0% +convolution and frequency okay +so let's think about that a little more + + align:start position:0% +so let's think about that a little more + + + align:start position:0% +so let's think about that a little more +what I just talked about was the + + align:start position:0% +what I just talked about was the + + + align:start position:0% +what I just talked about was the +relationship between the Fourier + + align:start position:0% +relationship between the Fourier + + + align:start position:0% +relationship between the Fourier +transforms of X and XP but the goal is + + align:start position:0% +transforms of X and XP but the goal is + + + align:start position:0% +transforms of X and XP but the goal is +to think about the samples so what's the + + align:start position:0% +to think about the samples so what's the + + + align:start position:0% +to think about the samples so what's the +relationship between the DT the + + align:start position:0% +relationship between the DT the + + + align:start position:0% +relationship between the DT the +discrete-time fourier transform of the + + align:start position:0% +discrete-time fourier transform of the + + + align:start position:0% +discrete-time fourier transform of the +sampled signal and the continuous-time + + align:start position:0% +sampled signal and the continuous-time + + + align:start position:0% +sampled signal and the continuous-time +fourier transform of this impulse + + align:start position:0% +fourier transform of this impulse + + + align:start position:0% +fourier transform of this impulse +reconstruction right so I is already for + + align:start position:0% +reconstruction right so I is already for + + + align:start position:0% +reconstruction right so I is already for +you I've compared the frequency risk the + + align:start position:0% +you I've compared the frequency risk the + + + align:start position:0% +you I've compared the frequency risk the +Fourier representations of these two as + + align:start position:0% +Fourier representations of these two as + + + align:start position:0% +Fourier representations of these two as +an exercise you compare the frequency + + align:start position:0% +an exercise you compare the frequency + + + align:start position:0% +an exercise you compare the frequency +representations of those two and figure + + align:start position:0% +representations of those two and figure + + + align:start position:0% +representations of those two and figure +out if any of these are the right way to + + align:start position:0% +out if any of these are the right way to + + + align:start position:0% +out if any of these are the right way to +look at it so look at your neighbor + + align:start position:0% + + + + align:start position:0% + +so which one best describes the + + align:start position:0% +so which one best describes the + + + align:start position:0% +so which one best describes the +relationship between those fourier + + align:start position:0% +relationship between those fourier + + + align:start position:0% +relationship between those fourier +representations number 1 2 3 or none of + + align:start position:0% +representations number 1 2 3 or none of + + + align:start position:0% +representations number 1 2 3 or none of +the above ok so a hundred percent I + + align:start position:0% +the above ok so a hundred percent I + + + align:start position:0% +the above ok so a hundred percent I +think so easier question is X of e to + + align:start position:0% +think so easier question is X of e to + + + align:start position:0% +think so easier question is X of e to +the J Omega X of e to the J Omega so + + align:start position:0% +the J Omega X of e to the J Omega so + + + align:start position:0% +the J Omega X of e to the J Omega so +this way X of e to the J Omega is that a + + align:start position:0% +this way X of e to the J Omega is that a + + + align:start position:0% +this way X of e to the J Omega is that a +periodic or a periodic function of Omega + + align:start position:0% + + + + align:start position:0% + +periodic what's the period go to the + + align:start position:0% +periodic what's the period go to the + + + align:start position:0% +periodic what's the period go to the +period of X of e to the J Omega what's + + align:start position:0% +period of X of e to the J Omega what's + + + align:start position:0% +period of X of e to the J Omega what's +the period of e to the J Omega + + align:start position:0% + + + + align:start position:0% + +so I'm hearing about the three not quite + + align:start position:0% +so I'm hearing about the three not quite + + + align:start position:0% +so I'm hearing about the three not quite +correct answers they all kind of have + + align:start position:0% +correct answers they all kind of have + + + align:start position:0% +correct answers they all kind of have +the right stuff in them what's the + + align:start position:0% +the right stuff in them what's the + + + align:start position:0% +the right stuff in them what's the +period of e to the J Omega what's the + + align:start position:0% +period of e to the J Omega what's the + + + align:start position:0% +period of e to the J Omega what's the +period of cosine what's the period of + + align:start position:0% +period of cosine what's the period of + + + align:start position:0% +period of cosine what's the period of +cosine 2pi thank you okay so this one's + + align:start position:0% +cosine 2pi thank you okay so this one's + + + align:start position:0% +cosine 2pi thank you okay so this one's +periodic in 2pi so X of e to the J Omega + + align:start position:0% +periodic in 2pi so X of e to the J Omega + + + align:start position:0% +periodic in 2pi so X of e to the J Omega +is periodic and jus pi because e to the + + align:start position:0% +is periodic and jus pi because e to the + + + align:start position:0% +is periodic and jus pi because e to the +J Omega is periodic and do pi right + + align:start position:0% +J Omega is periodic and do pi right + + + align:start position:0% +J Omega is periodic and do pi right +how about XP of J Omega is that periodic + + align:start position:0% +how about XP of J Omega is that periodic + + + align:start position:0% +how about XP of J Omega is that periodic +or a periodic XP of J Omega XP is the + + align:start position:0% +or a periodic XP of J Omega XP is the + + + align:start position:0% +or a periodic XP of J Omega XP is the +signal that I got when I multiplied in + + align:start position:0% +signal that I got when I multiplied in + + + align:start position:0% +signal that I got when I multiplied in +the time domain X of T times P of T P of + + align:start position:0% +the time domain X of T times P of T P of + + + align:start position:0% +the time domain X of T times P of T P of +T being an impulse train okay an impulse + + align:start position:0% +T being an impulse train okay an impulse + + + align:start position:0% +T being an impulse train okay an impulse +train times a time domain signal and + + align:start position:0% +train times a time domain signal and + + + align:start position:0% +train times a time domain signal and +that's how I got XP and then XP is the + + align:start position:0% +that's how I got XP and then XP is the + + + align:start position:0% +that's how I got XP and then XP is the +transform of that is the transform of XP + + align:start position:0% +transform of that is the transform of XP + + + align:start position:0% +transform of that is the transform of XP +periodic or a periodic periodic what's + + align:start position:0% +periodic or a periodic periodic what's + + + align:start position:0% +periodic or a periodic periodic what's +the period of XP two PI over T precisely + + align:start position:0% +the period of XP two PI over T precisely + + + align:start position:0% +the period of XP two PI over T precisely +so this one is periodic in Omega is two + + align:start position:0% +so this one is periodic in Omega is two + + + align:start position:0% +so this one is periodic in Omega is two +pi I shouldn't write it that way I + + align:start position:0% + + + + align:start position:0% + +should say that the period is 2 pi and + + align:start position:0% +should say that the period is 2 pi and + + + align:start position:0% +should say that the period is 2 pi and +here the period of Omega is 2 PI over T + + align:start position:0% +here the period of Omega is 2 PI over T + + + align:start position:0% +here the period of Omega is 2 PI over T +so what's relationship between Omega and + + align:start position:0% +so what's relationship between Omega and + + + align:start position:0% +so what's relationship between Omega and +Omega in order to make a function so in + + align:start position:0% +Omega in order to make a function so in + + + align:start position:0% +Omega in order to make a function so in +order to make a function that is similar + + align:start position:0% +order to make a function that is similar + + + align:start position:0% +order to make a function that is similar +we're going to have to have Omega is + + align:start position:0% +we're going to have to have Omega is + + + align:start position:0% +we're going to have to have Omega is +omega over T ok we're going to have to + + align:start position:0% +omega over T ok we're going to have to + + + align:start position:0% +omega over T ok we're going to have to +convert the units of capital Omega which + + align:start position:0% +convert the units of capital Omega which + + + align:start position:0% +convert the units of capital Omega which +are radians into the units of literal + + align:start position:0% +are radians into the units of literal + + + align:start position:0% +are radians into the units of literal +Omega which is radians per second so we + + align:start position:0% +Omega which is radians per second so we + + + align:start position:0% +Omega which is radians per second so we +need a time in the bottom okay and if + + align:start position:0% +need a time in the bottom okay and if + + + align:start position:0% +need a time in the bottom okay and if +you want to be a little bit more formal + + align:start position:0% +you want to be a little bit more formal + + + align:start position:0% +you want to be a little bit more formal +on it you can just write out the + + align:start position:0% +on it you can just write out the + + + align:start position:0% +on it you can just write out the +definitions right I did this last time + + align:start position:0% +definitions right I did this last time + + + align:start position:0% +definitions right I did this last time +this was from last like two lectures ago + + align:start position:0% +this was from last like two lectures ago + + + align:start position:0% +this was from last like two lectures ago +so here's the definition of the + + align:start position:0% +so here's the definition of the + + + align:start position:0% +so here's the definition of the +discrete-time fourier transform right + + align:start position:0% +discrete-time fourier transform right + + + align:start position:0% +discrete-time fourier transform right +you take the samples and weight them by + + align:start position:0% +you take the samples and weight them by + + + align:start position:0% +you take the samples and weight them by +e to the minus J Omega n here's the + + align:start position:0% +e to the minus J Omega n here's the + + + align:start position:0% +e to the minus J Omega n here's the +definition of the CT Fourier transform + + align:start position:0% +definition of the CT Fourier transform + + + align:start position:0% +definition of the CT Fourier transform +where I've substituted X P of T is this + + align:start position:0% +where I've substituted X P of T is this + + + align:start position:0% +where I've substituted X P of T is this +thing right isn't it it's a string of + + align:start position:0% +thing right isn't it it's a string of + + + align:start position:0% +thing right isn't it it's a string of +impulses each weighted by X van and then + + align:start position:0% +impulses each weighted by X van and then + + + align:start position:0% +impulses each weighted by X van and then +I interchange the integral in the + + align:start position:0% +I interchange the integral in the + + + align:start position:0% +I interchange the integral in the +summation and I don't worry about + + align:start position:0% +summation and I don't worry about + + + align:start position:0% +summation and I don't worry about +whether it's going to work or not you + + align:start position:0% +whether it's going to work or not you + + + align:start position:0% +whether it's going to work or not you +have to take a follow-on course and of + + align:start position:0% +have to take a follow-on course and of + + + align:start position:0% +have to take a follow-on course and of +course 18 in order to figure out whether + + align:start position:0% +course 18 in order to figure out whether + + + align:start position:0% +course 18 in order to figure out whether +that makes sense or not but it does so I + + align:start position:0% +that makes sense or not but it does so I + + + align:start position:0% +that makes sense or not but it does so I +interchange the order and then the end + + align:start position:0% +interchange the order and then the end + + + align:start position:0% +interchange the order and then the end +part factors out and this just sifts out + + align:start position:0% +part factors out and this just sifts out + + + align:start position:0% +part factors out and this just sifts out +the value of Omega at t at the value of + + align:start position:0% +the value of Omega at t at the value of + + + align:start position:0% +the value of Omega at t at the value of +T at NT so I replace then this T with NT + + align:start position:0% +T at NT so I replace then this T with NT + + + align:start position:0% +T at NT so I replace then this T with NT +the integral goes away and I end up with + + align:start position:0% +the integral goes away and I end up with + + + align:start position:0% +the integral goes away and I end up with +something that looks almost exactly like + + align:start position:0% +something that looks almost exactly like + + + align:start position:0% +something that looks almost exactly like +that except that capital Omega has + + align:start position:0% +that except that capital Omega has + + + align:start position:0% +that except that capital Omega has +turned into a little Omega times T okay + + align:start position:0% +turned into a little Omega times T okay + + + align:start position:0% +turned into a little Omega times T okay +so the discrete-time fourier transform + + align:start position:0% +so the discrete-time fourier transform + + + align:start position:0% +so the discrete-time fourier transform +is just a scaled in frequency version of + + align:start position:0% +is just a scaled in frequency version of + + + align:start position:0% +is just a scaled in frequency version of +this impulse sampled original signal + + align:start position:0% +this impulse sampled original signal + + + align:start position:0% +this impulse sampled original signal +that okay so the impulse reconstruction + + align:start position:0% +that okay so the impulse reconstruction + + + align:start position:0% +that okay so the impulse reconstruction +is related to the Fourier transform of + + align:start position:0% +is related to the Fourier transform of + + + align:start position:0% +is related to the Fourier transform of +the impulse reconstruction is related to + + align:start position:0% +the impulse reconstruction is related to + + + align:start position:0% +the impulse reconstruction is related to +the Fourier transform of samples by + + align:start position:0% +the Fourier transform of samples by + + + align:start position:0% +the Fourier transform of samples by +scaling frequencies that way so they so + + align:start position:0% +scaling frequencies that way so they so + + + align:start position:0% +scaling frequencies that way so they so +those representations have the same + + align:start position:0% +those representations have the same + + + align:start position:0% +those representations have the same +information precisely except for the + + align:start position:0% +information precisely except for the + + + align:start position:0% +information precisely except for the +scaling of frequency right the period in + + align:start position:0% +scaling of frequency right the period in + + + align:start position:0% +scaling of frequency right the period in +the bottom waveform is 2pi the period + + align:start position:0% +the bottom waveform is 2pi the period + + + align:start position:0% +the bottom waveform is 2pi the period +and this one is 2pi over capital T okay + + align:start position:0% +and this one is 2pi over capital T okay + + + align:start position:0% +and this one is 2pi over capital T okay +so the answer to the question then is + + align:start position:0% +so the answer to the question then is + + + align:start position:0% +so the answer to the question then is +easy under what conditions does the + + align:start position:0% +easy under what conditions does the + + + align:start position:0% +easy under what conditions does the +original question was under what + + align:start position:0% +original question was under what + + + align:start position:0% +original question was under what +conditions can i sample in a way that + + align:start position:0% +conditions can i sample in a way that + + + align:start position:0% +conditions can i sample in a way that +preserves the information in the + + align:start position:0% +preserves the information in the + + + align:start position:0% +preserves the information in the +original signal + + align:start position:0% +original signal + + + align:start position:0% +original signal +well this diagram makes it relatively + + align:start position:0% +well this diagram makes it relatively + + + align:start position:0% +well this diagram makes it relatively +clear if I have if the original X was + + align:start position:0% +clear if I have if the original X was + + + align:start position:0% +clear if I have if the original X was +just one of these triangles + + align:start position:0% +just one of these triangles + + + align:start position:0% +just one of these triangles +and as XP is the periodic extension of + + align:start position:0% +and as XP is the periodic extension of + + + align:start position:0% +and as XP is the periodic extension of +that then so long as the periodic + + align:start position:0% +that then so long as the periodic + + + align:start position:0% +that then so long as the periodic +extensions don't overlap with each other + + align:start position:0% +extensions don't overlap with each other + + + align:start position:0% +extensions don't overlap with each other +I can derive X from XP by simply + + align:start position:0% +I can derive X from XP by simply + + + align:start position:0% +I can derive X from XP by simply +low-pass filtering throw away the + + align:start position:0% +low-pass filtering throw away the + + + align:start position:0% +low-pass filtering throw away the +frequencies that got introduced by the + + align:start position:0% +frequencies that got introduced by the + + + align:start position:0% +frequencies that got introduced by the +convolution with an impulse train so as + + align:start position:0% +convolution with an impulse train so as + + + align:start position:0% +convolution with an impulse train so as +long as the frequencies don't overlap as + + align:start position:0% +long as the frequencies don't overlap as + + + align:start position:0% +long as the frequencies don't overlap as +long as there's a clean spot here where + + align:start position:0% +long as there's a clean spot here where + + + align:start position:0% +long as there's a clean spot here where +there's nothing happening as long as the + + align:start position:0% +there's nothing happening as long as the + + + align:start position:0% +there's nothing happening as long as the +frequencies of the periodic extensions + + align:start position:0% +frequencies of the periodic extensions + + + align:start position:0% +frequencies of the periodic extensions +don't overlap then I can sample in a way + + align:start position:0% +don't overlap then I can sample in a way + + + align:start position:0% +don't overlap then I can sample in a way +that is that contains all of the + + align:start position:0% +that is that contains all of the + + + align:start position:0% +that is that contains all of the +information of the original so long as + + align:start position:0% +information of the original so long as + + + align:start position:0% +information of the original so long as +when I'm all done I low pass filter + + align:start position:0% +when I'm all done I low pass filter + + + align:start position:0% +when I'm all done I low pass filter +that's called the sampling theorem so + + align:start position:0% +that's called the sampling theorem so + + + align:start position:0% +that's called the sampling theorem so +the sampling theorem which is not at all + + align:start position:0% +the sampling theorem which is not at all + + + align:start position:0% +the sampling theorem which is not at all +obvious if you don't think about the + + align:start position:0% +obvious if you don't think about the + + + align:start position:0% +obvious if you don't think about the +Fourier space if you only started with + + align:start position:0% +Fourier space if you only started with + + + align:start position:0% +Fourier space if you only started with +the time domain representations that I + + align:start position:0% +the time domain representations that I + + + align:start position:0% +the time domain representations that I +showed in the first few slides it's not + + align:start position:0% +showed in the first few slides it's not + + + align:start position:0% +showed in the first few slides it's not +at all obvious that there even is a way + + align:start position:0% +at all obvious that there even is a way + + + align:start position:0% +at all obvious that there even is a way +to sample in an information preserving + + align:start position:0% +to sample in an information preserving + + + align:start position:0% +to sample in an information preserving +fashion but what we've just seen is that + + align:start position:0% +fashion but what we've just seen is that + + + align:start position:0% +fashion but what we've just seen is that +it's really simple to think about it in + + align:start position:0% +it's really simple to think about it in + + + align:start position:0% +it's really simple to think about it in +the Fourier domain thinking about in the + + align:start position:0% +the Fourier domain thinking about in the + + + align:start position:0% +the Fourier domain thinking about in the +Fourier domain gives rise to what we + + align:start position:0% +Fourier domain gives rise to what we + + + align:start position:0% +Fourier domain gives rise to what we +call the sampling theorem which says + + align:start position:0% +call the sampling theorem which says + + + align:start position:0% +call the sampling theorem which says +that if a signal is band limited that + + align:start position:0% +that if a signal is band limited that + + + align:start position:0% +that if a signal is band limited that +has to do with this overlap part if the + + align:start position:0% +has to do with this overlap part if the + + + align:start position:0% +has to do with this overlap part if the +signal is band limited that means that + + align:start position:0% +signal is band limited that means that + + + align:start position:0% +signal is band limited that means that +all of the non zero frequency elements + + align:start position:0% +all of the non zero frequency elements + + + align:start position:0% +all of the non zero frequency elements +are in some band of frequencies nothing + + align:start position:0% +are in some band of frequencies nothing + + + align:start position:0% +are in some band of frequencies nothing +outside that band outside some band I + + align:start position:0% +outside that band outside some band I + + + align:start position:0% +outside that band outside some band I +don't care what the band is but outside + + align:start position:0% +don't care what the band is but outside + + + align:start position:0% +don't care what the band is but outside +that band the Fourier transform has to + + align:start position:0% +that band the Fourier transform has to + + + align:start position:0% +that band the Fourier transform has to +be 0 if the Fourier transform is 0 + + align:start position:0% +be 0 if the Fourier transform is 0 + + + align:start position:0% +be 0 if the Fourier transform is 0 +outside some band then it's possible to + + align:start position:0% +outside some band then it's possible to + + + align:start position:0% +outside some band then it's possible to +sample in a way that doesn't that + + align:start position:0% +sample in a way that doesn't that + + + align:start position:0% +sample in a way that doesn't that +preserves all the information so long as + + align:start position:0% +preserves all the information so long as + + + align:start position:0% +preserves all the information so long as +I sample fast enough so if it's if the + + align:start position:0% +I sample fast enough so if it's if the + + + align:start position:0% +I sample fast enough so if it's if the +original signal is band limited so the + + align:start position:0% +original signal is band limited so the + + + align:start position:0% +original signal is band limited so the +Fourier transform is 0 for frequencies + + align:start position:0% +Fourier transform is 0 for frequencies + + + align:start position:0% +Fourier transform is 0 for frequencies +above some frequency Omega M then X is + + align:start position:0% +above some frequency Omega M then X is + + + align:start position:0% +above some frequency Omega M then X is +uniquely determined by its samples + + align:start position:0% +uniquely determined by its samples + + + align:start position:0% +uniquely determined by its samples +uniquely means that I can do an inverse + + align:start position:0% +uniquely means that I can do an inverse + + + align:start position:0% +uniquely means that I can do an inverse +so it's uniquely determined by the + + align:start position:0% +so it's uniquely determined by the + + + align:start position:0% +so it's uniquely determined by the +samples + + align:start position:0% +samples + + + align:start position:0% +samples +only if Omega asks this sampling + + align:start position:0% +only if Omega asks this sampling + + + align:start position:0% +only if Omega asks this sampling +frequency which is two PI over T that's + + align:start position:0% +frequency which is two PI over T that's + + + align:start position:0% +frequency which is two PI over T that's +the period of the impulse train so if + + align:start position:0% +the period of the impulse train so if + + + align:start position:0% +the period of the impulse train so if +two PI over T exceeds twice the + + align:start position:0% +two PI over T exceeds twice the + + + align:start position:0% +two PI over T exceeds twice the +frequency of the band limit we'll see in + + align:start position:0% +frequency of the band limit we'll see in + + + align:start position:0% +frequency of the band limit we'll see in +a minute where the factor of two comes + + align:start position:0% +a minute where the factor of two comes + + + align:start position:0% +a minute where the factor of two comes +from the factor of two comes from + + align:start position:0% +from the factor of two comes from + + + align:start position:0% +from the factor of two comes from +negative frequencies so the sampling + + align:start position:0% +negative frequencies so the sampling + + + align:start position:0% +negative frequencies so the sampling +theorem says that there is a way for a + + align:start position:0% +theorem says that there is a way for a + + + align:start position:0% +theorem says that there is a way for a +certain kind of signal signals that are + + align:start position:0% +certain kind of signal signals that are + + + align:start position:0% +certain kind of signal signals that are +band-limited can be sampled in a way + + align:start position:0% +band-limited can be sampled in a way + + + align:start position:0% +band-limited can be sampled in a way +that preserves all the information so + + align:start position:0% +that preserves all the information so + + + align:start position:0% +that preserves all the information so +here's a summary if you sample uniformly + + align:start position:0% +here's a summary if you sample uniformly + + + align:start position:0% +here's a summary if you sample uniformly +that's not the only kind of sampling we + + align:start position:0% +that's not the only kind of sampling we + + + align:start position:0% +that's not the only kind of sampling we +do in practice but it's the basis of all + + align:start position:0% +do in practice but it's the basis of all + + + align:start position:0% +do in practice but it's the basis of all +of our theories for the way sampling + + align:start position:0% +of our theories for the way sampling + + + align:start position:0% +of our theories for the way sampling +works so that's the only one we'll do in + + align:start position:0% +works so that's the only one we'll do in + + + align:start position:0% +works so that's the only one we'll do in +double O 3 but just for your + + align:start position:0% +double O 3 but just for your + + + align:start position:0% +double O 3 but just for your +intellectual area fication there are + + align:start position:0% +intellectual area fication there are + + + align:start position:0% +intellectual area fication there are +more sophisticated ways to sample and in + + align:start position:0% +more sophisticated ways to sample and in + + + align:start position:0% +more sophisticated ways to sample and in +fact that's a topic of current research + + align:start position:0% +fact that's a topic of current research + + + align:start position:0% +fact that's a topic of current research +but for the time being we're only going + + align:start position:0% +but for the time being we're only going + + + align:start position:0% +but for the time being we're only going +to worry about uniform sampling if you + + align:start position:0% +to worry about uniform sampling if you + + + align:start position:0% +to worry about uniform sampling if you +sample a signal uniformly in time that + + align:start position:0% +sample a signal uniformly in time that + + + align:start position:0% +sample a signal uniformly in time that +is every T set capital T seconds then + + align:start position:0% +is every T set capital T seconds then + + + align:start position:0% +is every T set capital T seconds then +you can do band-limited reconstruction + + align:start position:0% +you can do band-limited reconstruction + + + align:start position:0% +you can do band-limited reconstruction +which means that replace every sample + + align:start position:0% +which means that replace every sample + + + align:start position:0% +which means that replace every sample +with an impulse weighted by the sample + + align:start position:0% +with an impulse weighted by the sample + + + align:start position:0% +with an impulse weighted by the sample +weight and spaced in time where it would + + align:start position:0% +weight and spaced in time where it would + + + align:start position:0% +weight and spaced in time where it would +have come from then run it through an + + align:start position:0% +have come from then run it through an + + + align:start position:0% +have come from then run it through an +ideal low-pass filter to get rid of the + + align:start position:0% +ideal low-pass filter to get rid of the + + + align:start position:0% +ideal low-pass filter to get rid of the +stuff that the high frequency copies and + + align:start position:0% +stuff that the high frequency copies and + + + align:start position:0% +stuff that the high frequency copies and +what comes out will be equal to that as + + align:start position:0% +what comes out will be equal to that as + + + align:start position:0% +what comes out will be equal to that as +long as you've satisfied this + + align:start position:0% +long as you've satisfied this + + + align:start position:0% +long as you've satisfied this +relationship that the frequencies that + + align:start position:0% +relationship that the frequencies that + + + align:start position:0% +relationship that the frequencies that +are contained in the signal must be less + + align:start position:0% +are contained in the signal must be less + + + align:start position:0% +are contained in the signal must be less +than the sampling frequency over to okay + + align:start position:0% +than the sampling frequency over to okay + + + align:start position:0% +than the sampling frequency over to okay +okay so what's the implication of the + + align:start position:0% +okay so what's the implication of the + + + align:start position:0% +okay so what's the implication of the +sampling theorem think about a + + align:start position:0% +sampling theorem think about a + + + align:start position:0% +sampling theorem think about a +particular problem we can hear sounds + + align:start position:0% +particular problem we can hear sounds + + + align:start position:0% +particular problem we can hear sounds +with frequency components that range + + align:start position:0% +with frequency components that range + + + align:start position:0% +with frequency components that range +from 20 Hertz to 20 kilohertz what's the + + align:start position:0% +from 20 Hertz to 20 kilohertz what's the + + + align:start position:0% +from 20 Hertz to 20 kilohertz what's the +minimum what's the biggest sampling + + align:start position:0% +minimum what's the biggest sampling + + + align:start position:0% +minimum what's the biggest sampling +interval T that we can use to retain all + + align:start position:0% +interval T that we can use to retain all + + + align:start position:0% +interval T that we can use to retain all +of the information in a signal that we + + align:start position:0% +of the information in a signal that we + + + align:start position:0% +of the information in a signal that we +can hear + + align:start position:0% + + + + align:start position:0% + +so what's the answer one two three four + + align:start position:0% +so what's the answer one two three four + + + align:start position:0% +so what's the answer one two three four +five six okay sort of shrinking number + + align:start position:0% +five six okay sort of shrinking number + + + align:start position:0% +five six okay sort of shrinking number +of votes and sort of a shrinking number + + align:start position:0% +of votes and sort of a shrinking number + + + align:start position:0% +of votes and sort of a shrinking number +of correct votes so it's about seventy + + align:start position:0% +of correct votes so it's about seventy + + + align:start position:0% +of correct votes so it's about seventy +five percent the only tricky part really + + align:start position:0% +five percent the only tricky part really + + + align:start position:0% +five percent the only tricky part really +is thinking about frequencies so I told + + align:start position:0% +is thinking about frequencies so I told + + + align:start position:0% +is thinking about frequencies so I told +you frequencies in the commonly used + + align:start position:0% +you frequencies in the commonly used + + + align:start position:0% +you frequencies in the commonly used +engineering terms I told you that we + + align:start position:0% +engineering terms I told you that we + + + align:start position:0% +engineering terms I told you that we +hear frequencies from 20 to 20,000 Hertz + + align:start position:0% +hear frequencies from 20 to 20,000 Hertz + + + align:start position:0% +hear frequencies from 20 to 20,000 Hertz +in this course we usually think about + + align:start position:0% +in this course we usually think about + + + align:start position:0% +in this course we usually think about +frequencies as Omega Radian frequency + + align:start position:0% +frequencies as Omega Radian frequency + + + align:start position:0% +frequencies as Omega Radian frequency +Hertz are cycles per second there's two + + align:start position:0% +Hertz are cycles per second there's two + + + align:start position:0% +Hertz are cycles per second there's two +PI radians cycles Hertz or cycles per + + align:start position:0% +PI radians cycles Hertz or cycles per + + + align:start position:0% +PI radians cycles Hertz or cycles per +second Radian frequency is cycles per + + align:start position:0% +second Radian frequency is cycles per + + + align:start position:0% +second Radian frequency is cycles per +second radians per second there's two PI + + align:start position:0% +second radians per second there's two PI + + + align:start position:0% +second radians per second there's two PI +radians per cycle okay sorry I screwed + + align:start position:0% +radians per cycle okay sorry I screwed + + + align:start position:0% +radians per cycle okay sorry I screwed +that up Hertz is cycles per second Omega + + align:start position:0% +that up Hertz is cycles per second Omega + + + align:start position:0% +that up Hertz is cycles per second Omega +is radians per second the conversion is + + align:start position:0% +is radians per second the conversion is + + + align:start position:0% +is radians per second the conversion is +two pi radians per cycle okay so we need + + align:start position:0% +two pi radians per cycle okay so we need + + + align:start position:0% +two pi radians per cycle okay so we need +to have the highest frequency in the + + align:start position:0% +to have the highest frequency in the + + + align:start position:0% +to have the highest frequency in the +signal has to be smaller than the + + align:start position:0% +signal has to be smaller than the + + + align:start position:0% +signal has to be smaller than the +sampling frequency divided by two the + + align:start position:0% +sampling frequency divided by two the + + + align:start position:0% +sampling frequency divided by two the +highest frequency in the signal is 2 pi + + align:start position:0% +highest frequency in the signal is 2 pi + + + align:start position:0% +highest frequency in the signal is 2 pi +fm if F is frequencies 20 to 20 + + align:start position:0% +fm if F is frequencies 20 to 20 + + + align:start position:0% +fm if F is frequencies 20 to 20 +kilohertz and the sampling frequency is + + align:start position:0% +kilohertz and the sampling frequency is + + + align:start position:0% +kilohertz and the sampling frequency is +2 PI over capital T so you clear the + + align:start position:0% +2 PI over capital T so you clear the + + + align:start position:0% +2 PI over capital T so you clear the +fraction and figure out the T has to be + + align:start position:0% +fraction and figure out the T has to be + + + align:start position:0% +fraction and figure out the T has to be +smaller than 25 microseconds okay okay + + align:start position:0% +smaller than 25 microseconds okay okay + + + align:start position:0% +smaller than 25 microseconds okay okay +so the idea then is that there's a way + + align:start position:0% +so the idea then is that there's a way + + + align:start position:0% +so the idea then is that there's a way +of thinking about any signal with a + + align:start position:0% +of thinking about any signal with a + + + align:start position:0% +of thinking about any signal with a +finite bandwidth there's a way of + + align:start position:0% +finite bandwidth there's a way of + + + align:start position:0% +finite bandwidth there's a way of +sampling using uniform sampling so that + + align:start position:0% +sampling using uniform sampling so that + + + align:start position:0% +sampling using uniform sampling so that +you can sample that signal without loss + + align:start position:0% +you can sample that signal without loss + + + align:start position:0% +you can sample that signal without loss +of information all you need to do is + + align:start position:0% +of information all you need to do is + + + align:start position:0% +of information all you need to do is +figure out how frequently you need the + + align:start position:0% +figure out how frequently you need the + + + align:start position:0% +figure out how frequently you need the +Sandpoint yes + + align:start position:0% + + + + align:start position:0% + +if a signal is not band-limited you have + + align:start position:0% +if a signal is not band-limited you have + + + align:start position:0% +if a signal is not band-limited you have +a problem so the question is what is to + + align:start position:0% +a problem so the question is what is to + + + align:start position:0% +a problem so the question is what is to +what extent is it possible to sample a + + align:start position:0% +what extent is it possible to sample a + + + align:start position:0% +what extent is it possible to sample a +signal that is not band-limited so + + align:start position:0% +signal that is not band-limited so + + + align:start position:0% +signal that is not band-limited so +that's the next topic so the question is + + align:start position:0% +that's the next topic so the question is + + + align:start position:0% +that's the next topic so the question is +the the question I'm going to address + + align:start position:0% +the the question I'm going to address + + + align:start position:0% +the the question I'm going to address +now is well what happens if you don't + + align:start position:0% +now is well what happens if you don't + + + align:start position:0% +now is well what happens if you don't +satisfy the sampling theorem what if + + align:start position:0% +satisfy the sampling theorem what if + + + align:start position:0% +satisfy the sampling theorem what if +there are frequency components that are + + align:start position:0% +there are frequency components that are + + + align:start position:0% +there are frequency components that are +outside the admissible band the the + + align:start position:0% +outside the admissible band the the + + + align:start position:0% +outside the admissible band the the +Missal the admissible region of + + align:start position:0% +Missal the admissible region of + + + align:start position:0% +Missal the admissible region of +frequencies okay so to think about that + + align:start position:0% +frequencies okay so to think about that + + + align:start position:0% +frequencies okay so to think about that +I'm going to think about this as a model + + align:start position:0% +I'm going to think about this as a model + + + align:start position:0% +I'm going to think about this as a model +of sampling so I think about and the + + align:start position:0% +of sampling so I think about and the + + + align:start position:0% +of sampling so I think about and the +value of the model is it is entirely in + + align:start position:0% +value of the model is it is entirely in + + + align:start position:0% +value of the model is it is entirely in +CT it gets confusing when you mix + + align:start position:0% +CT it gets confusing when you mix + + + align:start position:0% +CT it gets confusing when you mix +domains and you have to compare this + + align:start position:0% +domains and you have to compare this + + + align:start position:0% +domains and you have to compare this +kind of a frequency to that kind of a + + align:start position:0% +kind of a frequency to that kind of a + + + align:start position:0% +kind of a frequency to that kind of a +frequency so what I'm going to do is + + align:start position:0% +frequency so what I'm going to do is + + + align:start position:0% +frequency so what I'm going to do is +think about it entirely in CT by making + + align:start position:0% +think about it entirely in CT by making + + + align:start position:0% +think about it entirely in CT by making +a model of how sampling works sampling + + align:start position:0% +a model of how sampling works sampling + + + align:start position:0% +a model of how sampling works sampling +is equivalent to take the original + + align:start position:0% +is equivalent to take the original + + + align:start position:0% +is equivalent to take the original +signal that you're trying to sample + + align:start position:0% +signal that you're trying to sample + + + align:start position:0% +signal that you're trying to sample +multiplied by an impulse train showed + + align:start position:0% +multiplied by an impulse train showed + + + align:start position:0% +multiplied by an impulse train showed +here you get out this XP thing that + + align:start position:0% +here you get out this XP thing that + + + align:start position:0% +here you get out this XP thing that +we've been talking about and then run + + align:start position:0% +we've been talking about and then run + + + align:start position:0% +we've been talking about and then run +that through an ideal low-pass filter + + align:start position:0% +that through an ideal low-pass filter + + + align:start position:0% +that through an ideal low-pass filter +and if this comes out looking like that + + align:start position:0% +and if this comes out looking like that + + + align:start position:0% +and if this comes out looking like that +then it was the it can be sampling + + align:start position:0% +then it was the it can be sampling + + + align:start position:0% +then it was the it can be sampling +preserves all of the information now + + align:start position:0% +preserves all of the information now + + + align:start position:0% +preserves all of the information now +what I want to do is think about what + + align:start position:0% +what I want to do is think about what + + + align:start position:0% +what I want to do is think about what +happens when I put in a signal for which + + align:start position:0% +happens when I put in a signal for which + + + align:start position:0% +happens when I put in a signal for which +that doesn't hold so let's start with + + align:start position:0% +that doesn't hold so let's start with + + + align:start position:0% +that doesn't hold so let's start with +the simplest possible case let's think + + align:start position:0% +the simplest possible case let's think + + + align:start position:0% +the simplest possible case let's think +about a tone so a signal that contains a + + align:start position:0% +about a tone so a signal that contains a + + + align:start position:0% +about a tone so a signal that contains a +single frequency component so I'm + + align:start position:0% +single frequency component so I'm + + + align:start position:0% +single frequency component so I'm +representing that by so say a cosine + + align:start position:0% +representing that by so say a cosine + + + align:start position:0% +representing that by so say a cosine +wave cosine Omega naught T so I'm + + align:start position:0% +wave cosine Omega naught T so I'm + + + align:start position:0% +wave cosine Omega naught T so I'm +representing that by two impulses + + align:start position:0% +representing that by two impulses + + + align:start position:0% +representing that by two impulses +Euler's equation and I'm thinking about + + align:start position:0% +Euler's equation and I'm thinking about + + + align:start position:0% +Euler's equation and I'm thinking about +some sampling waveform where I'm looking + + align:start position:0% +some sampling waveform where I'm looking + + + align:start position:0% +some sampling waveform where I'm looking +at it here in frequency so the spacing + + align:start position:0% +at it here in frequency so the spacing + + + align:start position:0% +at it here in frequency so the spacing +is 2 pi over T and if the frequencies in + + align:start position:0% +is 2 pi over T and if the frequencies in + + + align:start position:0% +is 2 pi over T and if the frequencies in +the signal are smaller than half of the + + align:start position:0% +the signal are smaller than half of the + + + align:start position:0% +the signal are smaller than half of the +maximum frequency Omega s everything + + align:start position:0% +maximum frequency Omega s everything + + + align:start position:0% +maximum frequency Omega s everything +should work and you can sort of see in + + align:start position:0% +should work and you can sort of see in + + + align:start position:0% +should work and you can sort of see in +the Fourier picture what's happening + + align:start position:0% +the Fourier picture what's happening + + + align:start position:0% +the Fourier picture what's happening +when I convolve these two signals I'm + + align:start position:0% +when I convolve these two signals I'm + + + align:start position:0% +when I convolve these two signals I'm +multiplying in time so I'm convulsing in + + align:start position:0% +multiplying in time so I'm convulsing in + + + align:start position:0% +multiplying in time so I'm convulsing in +frequency when I convolve this with the + + align:start position:0% +frequency when I convolve this with the + + + align:start position:0% +frequency when I convolve this with the +impulse train this impulse brings this + + align:start position:0% +impulse train this impulse brings this + + + align:start position:0% +impulse train this impulse brings this +pair of frequencies here but this + + align:start position:0% +pair of frequencies here but this + + + align:start position:0% +pair of frequencies here but this +impulse brings this pair up here and + + align:start position:0% +impulse brings this pair up here and + + + align:start position:0% +impulse brings this pair up here and +then this one brings this pair up here + + align:start position:0% +then this one brings this pair up here + + + align:start position:0% +then this one brings this pair up here +so I repeat so I get a repetition then + + align:start position:0% +so I repeat so I get a repetition then + + + align:start position:0% +so I repeat so I get a repetition then +of the original two at integer multiples + + align:start position:0% +of the original two at integer multiples + + + align:start position:0% +of the original two at integer multiples +of Omega s ok so if I low pass filter + + align:start position:0% +of Omega s ok so if I low pass filter + + + align:start position:0% +of Omega s ok so if I low pass filter +then with the red line everything's fine + + align:start position:0% +then with the red line everything's fine + + + align:start position:0% +then with the red line everything's fine +I end up with a signal at the output the + + align:start position:0% +I end up with a signal at the output the + + + align:start position:0% +I end up with a signal at the output the +same as signals the input no problem + + align:start position:0% +same as signals the input no problem + + + align:start position:0% +same as signals the input no problem +what happens however as I increase + + align:start position:0% +what happens however as I increase + + + align:start position:0% +what happens however as I increase +frequency same thing the originals are + + align:start position:0% +frequency same thing the originals are + + + align:start position:0% +frequency same thing the originals are +reproduced here the modulation by this + + align:start position:0% +reproduced here the modulation by this + + + align:start position:0% +reproduced here the modulation by this +brings this up to here the low pass + + align:start position:0% +brings this up to here the low pass + + + align:start position:0% +brings this up to here the low pass +filter still separates it out the + + align:start position:0% +filter still separates it out the + + + align:start position:0% +filter still separates it out the +problem is here now I'm running into + + align:start position:0% +problem is here now I'm running into + + + align:start position:0% +problem is here now I'm running into +trouble because the the original signal + + align:start position:0% +trouble because the the original signal + + + align:start position:0% +trouble because the the original signal +fell right on the edge of my limit Omega + + align:start position:0% +fell right on the edge of my limit Omega + + + align:start position:0% +fell right on the edge of my limit Omega +s over 2 and the problem is even more + + align:start position:0% +s over 2 and the problem is even more + + + align:start position:0% +s over 2 and the problem is even more +clear if I go to an even higher + + align:start position:0% +clear if I go to an even higher + + + align:start position:0% +clear if I go to an even higher +frequency so now this component is + + align:start position:0% +frequency so now this component is + + + align:start position:0% +frequency so now this component is +coming out here which is outside the + + align:start position:0% +coming out here which is outside the + + + align:start position:0% +coming out here which is outside the +bought the box the thing that's + + align:start position:0% +bought the box the thing that's + + + align:start position:0% +bought the box the thing that's +happening though is that convolution + + align:start position:0% +happening though is that convolution + + + align:start position:0% +happening though is that convolution +with this guy is bringing in an element + + align:start position:0% +with this guy is bringing in an element + + + align:start position:0% +with this guy is bringing in an element +that is spaced by Omega s and it's now + + align:start position:0% +that is spaced by Omega s and it's now + + + align:start position:0% +that is spaced by Omega s and it's now +inside the box that's bad everybody see + + align:start position:0% +inside the box that's bad everybody see + + + align:start position:0% +inside the box that's bad everybody see +what's happening so I'm just studying + + align:start position:0% +what's happening so I'm just studying + + + align:start position:0% +what's happening so I'm just studying +what happens as I have one frequency and + + align:start position:0% +what happens as I have one frequency and + + + align:start position:0% +what happens as I have one frequency and +vary the frequency if I have a tone at a + + align:start position:0% +vary the frequency if I have a tone at a + + + align:start position:0% +vary the frequency if I have a tone at a +single frequency and I vary the + + align:start position:0% +single frequency and I vary the + + + align:start position:0% +single frequency and I vary the +frequency of the tone as long as the + + align:start position:0% +frequency of the tone as long as the + + + align:start position:0% +frequency of the tone as long as the +frequency is inside my limit Omega s + + align:start position:0% +frequency is inside my limit Omega s + + + align:start position:0% +frequency is inside my limit Omega s +over 2 I'm fine + + align:start position:0% +over 2 I'm fine + + + align:start position:0% +over 2 I'm fine +the low pass filter reconstructs the + + align:start position:0% +the low pass filter reconstructs the + + + align:start position:0% +the low pass filter reconstructs the +original but something bizarre happens + + align:start position:0% +original but something bizarre happens + + + align:start position:0% +original but something bizarre happens +whenever I'm outside and to see what's + + align:start position:0% +whenever I'm outside and to see what's + + + align:start position:0% +whenever I'm outside and to see what's +going on it's easy it's easiest to see + + align:start position:0% +going on it's easy it's easiest to see + + + align:start position:0% +going on it's easy it's easiest to see +what's going on by making a map between + + align:start position:0% +what's going on by making a map between + + + align:start position:0% +what's going on by making a map between +the input frequency and the apparent + + align:start position:0% +the input frequency and the apparent + + + align:start position:0% +the input frequency and the apparent +frequency the apparent frequency at the + + align:start position:0% +frequency the apparent frequency at the + + + align:start position:0% +frequency the apparent frequency at the +output so what happens if I'm at a low + + align:start position:0% +output so what happens if I'm at a low + + + align:start position:0% +output so what happens if I'm at a low +frequency I'm on a linear relationship + + align:start position:0% +frequency I'm on a linear relationship + + + align:start position:0% +frequency I'm on a linear relationship +between the + + align:start position:0% +between the + + + align:start position:0% +between the +put frequency output the output + + align:start position:0% +put frequency output the output + + + align:start position:0% +put frequency output the output +reproduces the input exactly and you can + + align:start position:0% +reproduces the input exactly and you can + + + align:start position:0% +reproduces the input exactly and you can +see as I'm increasing the frequency I'm + + align:start position:0% +see as I'm increasing the frequency I'm + + + align:start position:0% +see as I'm increasing the frequency I'm +just sampling this function at a + + align:start position:0% +just sampling this function at a + + + align:start position:0% +just sampling this function at a +different place but when I go higher it + + align:start position:0% +different place but when I go higher it + + + align:start position:0% +different place but when I go higher it +appears as though the frequency got + + align:start position:0% +appears as though the frequency got + + + align:start position:0% +appears as though the frequency got +smaller okay + + align:start position:0% +smaller okay + + + align:start position:0% +smaller okay +we call that aliasing this is a question + + align:start position:0% +we call that aliasing this is a question + + + align:start position:0% +we call that aliasing this is a question +to get you to think through alias angle + + align:start position:0% +to get you to think through alias angle + + + align:start position:0% +to get you to think through alias angle +but in the interest of time because I + + align:start position:0% +but in the interest of time because I + + + align:start position:0% +but in the interest of time because I +have a demo I'll leave this for you to + + align:start position:0% +have a demo I'll leave this for you to + + + align:start position:0% +have a demo I'll leave this for you to +think about so the question is thinking + + align:start position:0% +think about so the question is thinking + + + align:start position:0% +think about so the question is thinking +about what's the effect of aliasing and + + align:start position:0% +about what's the effect of aliasing and + + + align:start position:0% +about what's the effect of aliasing and +where do the new frequencies land + + align:start position:0% +where do the new frequencies land + + + align:start position:0% +where do the new frequencies land +relative to the input frequency right + + align:start position:0% +relative to the input frequency right + + + align:start position:0% +relative to the input frequency right +they have this funny folding property + + align:start position:0% +they have this funny folding property + + + align:start position:0% +they have this funny folding property +and the effect of the folding property + + align:start position:0% +and the effect of the folding property + + + align:start position:0% +and the effect of the folding property +kind of wreaks havoc so I'll skip this + + align:start position:0% +kind of wreaks havoc so I'll skip this + + + align:start position:0% +kind of wreaks havoc so I'll skip this +for now and just jump to the idea that + + align:start position:0% +for now and just jump to the idea that + + + align:start position:0% +for now and just jump to the idea that +the intuition that we get by thinking + + align:start position:0% +the intuition that we get by thinking + + + align:start position:0% +the intuition that we get by thinking +about single frequencies carries over to + + align:start position:0% +about single frequencies carries over to + + + align:start position:0% +about single frequencies carries over to +complex frequency representations so now + + align:start position:0% +complex frequency representations so now + + + align:start position:0% +complex frequency representations so now +what if my message what if my input had + + align:start position:0% +what if my message what if my input had + + + align:start position:0% +what if my message what if my input had +this triangular frequency Fourier + + align:start position:0% +this triangular frequency Fourier + + + align:start position:0% +this triangular frequency Fourier +transform rather than just a single + + align:start position:0% +transform rather than just a single + + + align:start position:0% +transform rather than just a single +spike and so I'm sampling it as showed + + align:start position:0% +spike and so I'm sampling it as showed + + + align:start position:0% +spike and so I'm sampling it as showed +here so this is my impulse training + + align:start position:0% +here so this is my impulse training + + + align:start position:0% +here so this is my impulse training +frequency and as before the message gets + + align:start position:0% +frequency and as before the message gets + + + align:start position:0% +frequency and as before the message gets +reproduced at integer multiples of Omega + + align:start position:0% +reproduced at integer multiples of Omega + + + align:start position:0% +reproduced at integer multiples of Omega +s and as long as the bandwidth of the + + align:start position:0% +s and as long as the bandwidth of the + + + align:start position:0% +s and as long as the bandwidth of the +message is small enough I can put the + + align:start position:0% +message is small enough I can put the + + + align:start position:0% +message is small enough I can put the +read low pass filter to sample to + + align:start position:0% +read low pass filter to sample to + + + align:start position:0% +read low pass filter to sample to +eliminate the copies from the periodic + + align:start position:0% +eliminate the copies from the periodic + + + align:start position:0% +eliminate the copies from the periodic +extension and I get an output that's + + align:start position:0% +extension and I get an output that's + + + align:start position:0% +extension and I get an output that's +equal to the input the problem is that + + align:start position:0% +equal to the input the problem is that + + + align:start position:0% +equal to the input the problem is that +if I increase the bandwidth of the + + align:start position:0% +if I increase the bandwidth of the + + + align:start position:0% +if I increase the bandwidth of the +implant as I increase the bandwidth of + + align:start position:0% +implant as I increase the bandwidth of + + + align:start position:0% +implant as I increase the bandwidth of +the input the margin between the base + + align:start position:0% +the input the margin between the base + + + align:start position:0% +the input the margin between the base +signal and the periodic extension gets + + align:start position:0% +signal and the periodic extension gets + + + align:start position:0% +signal and the periodic extension gets +smaller and if the free and if the + + align:start position:0% +smaller and if the free and if the + + + align:start position:0% +smaller and if the free and if the +bandwidth gets too great they begin to + + align:start position:0% +bandwidth gets too great they begin to + + + align:start position:0% +bandwidth gets too great they begin to +overlap so now if I low-pass filter this + + align:start position:0% +overlap so now if I low-pass filter this + + + align:start position:0% +overlap so now if I low-pass filter this +signal I pick up the desired blue part + + align:start position:0% +signal I pick up the desired blue part + + + align:start position:0% +signal I pick up the desired blue part +of this but the undesired green part + + align:start position:0% +of this but the undesired green part + + + align:start position:0% +of this but the undesired green part +that okay and the result is that the + + align:start position:0% +that okay and the result is that the + + + align:start position:0% +that okay and the result is that the +signal is not a faithful reproduction of + + align:start position:0% +signal is not a faithful reproduction of + + + align:start position:0% +signal is not a faithful reproduction of +what I started with same sort of thing + + align:start position:0% +what I started with same sort of thing + + + align:start position:0% +what I started with same sort of thing +happens if I hold the message of + + align:start position:0% +happens if I hold the message of + + + align:start position:0% +happens if I hold the message of +constant and change the frequency space + + align:start position:0% +constant and change the frequency space + + + align:start position:0% +constant and change the frequency space +angle as long as I sample with big + + align:start position:0% +angle as long as I sample with big + + + align:start position:0% +angle as long as I sample with big +enough frequencies that is small enough + + align:start position:0% +enough frequencies that is small enough + + + align:start position:0% +enough frequencies that is small enough +times there's an inverse relationship + + align:start position:0% +times there's an inverse relationship + + + align:start position:0% +times there's an inverse relationship +between frequency and time if the + + align:start position:0% +between frequency and time if the + + + align:start position:0% +between frequency and time if the +frequency is big enough so the times are + + align:start position:0% +frequency is big enough so the times are + + + align:start position:0% +frequency is big enough so the times are +short enough I can reproduce what the + + align:start position:0% +short enough I can reproduce what the + + + align:start position:0% +short enough I can reproduce what the +out what the signal looked like but now + + align:start position:0% +out what the signal looked like but now + + + align:start position:0% +out what the signal looked like but now +if I change the sampling to happen + + align:start position:0% +if I change the sampling to happen + + + align:start position:0% +if I change the sampling to happen +slower I start to get aliasing so it's + + align:start position:0% +slower I start to get aliasing so it's + + + align:start position:0% +slower I start to get aliasing so it's +exactly analogous so that means that if + + align:start position:0% +exactly analogous so that means that if + + + align:start position:0% +exactly analogous so that means that if +you have a fixed signal there's some + + align:start position:0% +you have a fixed signal there's some + + + align:start position:0% +you have a fixed signal there's some +minimum rate at which you have to sample + + align:start position:0% +minimum rate at which you have to sample + + + align:start position:0% +minimum rate at which you have to sample +it in order to not lose information so + + align:start position:0% +it in order to not lose information so + + + align:start position:0% +it in order to not lose information so +what I want to do now is demonstrate + + align:start position:0% +what I want to do now is demonstrate + + + align:start position:0% +what I want to do now is demonstrate +that by thinking about music so I have a + + align:start position:0% +that by thinking about music so I have a + + + align:start position:0% +that by thinking about music so I have a +cut of music that I have that was + + align:start position:0% +cut of music that I have that was + + + align:start position:0% +cut of music that I have that was +originally taken from a CD so it was + + align:start position:0% +originally taken from a CD so it was + + + align:start position:0% +originally taken from a CD so it was +sampled at forty four point one + + align:start position:0% +sampled at forty four point one + + + align:start position:0% +sampled at forty four point one +kilohertz that's standard CD frequency + + align:start position:0% +kilohertz that's standard CD frequency + + + align:start position:0% +kilohertz that's standard CD frequency +sampling and ivory sampled it at 1/2 1/4 + + align:start position:0% +sampling and ivory sampled it at 1/2 1/4 + + + align:start position:0% +sampling and ivory sampled it at 1/2 1/4 +1/8 1/16 and I'm going to play what + + align:start position:0% +1/8 1/16 and I'm going to play what + + + align:start position:0% +1/8 1/16 and I'm going to play what +happens when I do these various + + align:start position:0% +happens when I do these various + + + align:start position:0% +happens when I do these various +resampling + + align:start position:0% + + + + align:start position:0% + +okay some of you may have been able to + + align:start position:0% +okay some of you may have been able to + + + align:start position:0% +okay some of you may have been able to +tell the difference so the idea is that + + align:start position:0% +tell the difference so the idea is that + + + align:start position:0% +tell the difference so the idea is that +by decreasing the rate at which I'm + + align:start position:0% +by decreasing the rate at which I'm + + + align:start position:0% +by decreasing the rate at which I'm +sampling it in time I get fewer samples + + align:start position:0% +sampling it in time I get fewer samples + + + align:start position:0% +sampling it in time I get fewer samples +in the total signal which makes it + + align:start position:0% +in the total signal which makes it + + + align:start position:0% +in the total signal which makes it +easier to store and increases the amount + + align:start position:0% +easier to store and increases the amount + + + align:start position:0% +easier to store and increases the amount +of stuff that I could put on a given + + align:start position:0% +of stuff that I could put on a given + + + align:start position:0% +of stuff that I could put on a given +medium that's good problem is it doesn't + + align:start position:0% +medium that's good problem is it doesn't + + + align:start position:0% +medium that's good problem is it doesn't +sound this good right so every step down + + align:start position:0% +sound this good right so every step down + + + align:start position:0% +sound this good right so every step down +this path resulted in half the + + align:start position:0% +this path resulted in half the + + + align:start position:0% +this path resulted in half the +information of the previous one which + + align:start position:0% +information of the previous one which + + + align:start position:0% +information of the previous one which +means that I could double the capacity + + align:start position:0% +means that I could double the capacity + + + align:start position:0% +means that I could double the capacity +of your mp3 player okay but there was + + align:start position:0% +of your mp3 player okay but there was + + + align:start position:0% +of your mp3 player okay but there was +distortions added because of this + + align:start position:0% +distortions added because of this + + + align:start position:0% +distortions added because of this +aliasing problem right because some of + + align:start position:0% +aliasing problem right because some of + + + align:start position:0% +aliasing problem right because some of +the frequencies at the lower sampling + + align:start position:0% +the frequencies at the lower sampling + + + align:start position:0% +the frequencies at the lower sampling +rates were too large to be faithfully + + align:start position:0% +rates were too large to be faithfully + + + align:start position:0% +rates were too large to be faithfully +reproduced by the sampling right they + + align:start position:0% +reproduced by the sampling right they + + + align:start position:0% +reproduced by the sampling right they +got moved they got alias to the wrong + + align:start position:0% +got moved they got alias to the wrong + + + align:start position:0% +got moved they got alias to the wrong +place that gives rise to sounds that are + + align:start position:0% +place that gives rise to sounds that are + + + align:start position:0% +place that gives rise to sounds that are +in harmonic and they sound bad + + align:start position:0% +in harmonic and they sound bad + + + align:start position:0% +in harmonic and they sound bad +okay so so yeah so this just + + align:start position:0% +okay so so yeah so this just + + + align:start position:0% +okay so so yeah so this just +recapitulates what we what we were + + align:start position:0% +recapitulates what we what we were + + + align:start position:0% +recapitulates what we what we were +seeing in the demo I started out barely + + align:start position:0% +seeing in the demo I started out barely + + + align:start position:0% +seeing in the demo I started out barely +having enough bandwidth to represent the + + align:start position:0% +having enough bandwidth to represent the + + + align:start position:0% +having enough bandwidth to represent the +original signal and as I made the + + align:start position:0% +original signal and as I made the + + + align:start position:0% +original signal and as I made the +sampling frequency smaller making the + + align:start position:0% +sampling frequency smaller making the + + + align:start position:0% +sampling frequency smaller making the +the distance between samples bigger as I + + align:start position:0% +the distance between samples bigger as I + + + align:start position:0% +the distance between samples bigger as I +made the frequency of the sampling + + align:start position:0% +made the frequency of the sampling + + + align:start position:0% +made the frequency of the sampling +smaller I started to get overlap and + + align:start position:0% +smaller I started to get overlap and + + + align:start position:0% +smaller I started to get overlap and +that's what sounded funny so the more + + align:start position:0% +that's what sounded funny so the more + + + align:start position:0% +that's what sounded funny so the more +the slower I sampled the more overlap + + align:start position:0% +the slower I sampled the more overlap + + + align:start position:0% +the slower I sampled the more overlap +and the funnier it sounded so the + + align:start position:0% +and the funnier it sounded so the + + + align:start position:0% +and the funnier it sounded so the +question is what can you do well how can + + align:start position:0% +question is what can you do well how can + + + align:start position:0% +question is what can you do well how can +you deal with that one way you can deal + + align:start position:0% +you deal with that one way you can deal + + + align:start position:0% +you deal with that one way you can deal +with that is what we call anti aliasing + + align:start position:0% +with that is what we call anti aliasing + + + align:start position:0% +with that is what we call anti aliasing +okay so it's very bad if you put a + + align:start position:0% +okay so it's very bad if you put a + + + align:start position:0% +okay so it's very bad if you put a +frequency into a sampling system where + + align:start position:0% +frequency into a sampling system where + + + align:start position:0% +frequency into a sampling system where +the frequency is too big to be + + align:start position:0% +the frequency is too big to be + + + align:start position:0% +the frequency is too big to be +faithfully reproduced because it comes + + align:start position:0% +faithfully reproduced because it comes + + + align:start position:0% +faithfully reproduced because it comes +out at a different frequency that cannot + + align:start position:0% +out at a different frequency that cannot + + + align:start position:0% +out at a different frequency that cannot +be determined from the output alone so + + align:start position:0% +be determined from the output alone so + + + align:start position:0% +be determined from the output alone so +how can you deal with that one way you + + align:start position:0% +how can you deal with that one way you + + + align:start position:0% +how can you deal with that one way you +can deal with it is to prease pre-filter + + align:start position:0% +can deal with it is to prease pre-filter + + + align:start position:0% +can deal with it is to prease pre-filter +take out everything that could be + + align:start position:0% +take out everything that could be + + + align:start position:0% +take out everything that could be +offensive + + align:start position:0% +offensive + + + align:start position:0% +offensive +before you sample that's called + + align:start position:0% +before you sample that's called + + + align:start position:0% +before you sample that's called +anti-aliasing and the result is not + + align:start position:0% +anti-aliasing and the result is not + + + align:start position:0% +anti-aliasing and the result is not +faithful reproduction of the original + + align:start position:0% +faithful reproduction of the original + + + align:start position:0% +faithful reproduction of the original +but it's at least faithful reproduction + + align:start position:0% +but it's at least faithful reproduction + + + align:start position:0% +but it's at least faithful reproduction +of the part of the band that is + + align:start position:0% +of the part of the band that is + + + align:start position:0% +of the part of the band that is +reproduced okay so it's not distortion + + align:start position:0% +reproduced okay so it's not distortion + + + align:start position:0% +reproduced okay so it's not distortion +free the transformation from the very + + align:start position:0% +free the transformation from the very + + + align:start position:0% +free the transformation from the very +input to the very output is not this + + align:start position:0% +input to the very output is not this + + + align:start position:0% +input to the very output is not this +there's not a unity transformation + + align:start position:0% +there's not a unity transformation + + + align:start position:0% +there's not a unity transformation +because you violated the sampling + + align:start position:0% +because you violated the sampling + + + align:start position:0% +because you violated the sampling +theorem but at least you don't elias + + align:start position:0% +theorem but at least you don't elias + + + align:start position:0% +theorem but at least you don't elias +frequencies - they're wrong place so the + + align:start position:0% +frequencies - they're wrong place so the + + + align:start position:0% +frequencies - they're wrong place so the +result I'll play so without + + align:start position:0% +result I'll play so without + + + align:start position:0% +result I'll play so without +anti-aliasing without anti-aliasing + + align:start position:0% +anti-aliasing without anti-aliasing + + + align:start position:0% +anti-aliasing without anti-aliasing +without with without with + + align:start position:0% + + + + align:start position:0% + +okay so the final one didn't sound + + align:start position:0% +okay so the final one didn't sound + + + align:start position:0% +okay so the final one didn't sound +exactly like the original but at least + + align:start position:0% +exactly like the original but at least + + + align:start position:0% +exactly like the original but at least +it wasn't grating so the idea then is + + align:start position:0% +it wasn't grating so the idea then is + + + align:start position:0% +it wasn't grating so the idea then is +just that sampling is very important and + + align:start position:0% +just that sampling is very important and + + + align:start position:0% +just that sampling is very important and +by thinking about in the Fourier domain + + align:start position:0% +by thinking about in the Fourier domain + + + align:start position:0% +by thinking about in the Fourier domain +we get a lot of insights that we + + align:start position:0% +we get a lot of insights that we + + + align:start position:0% +we get a lot of insights that we +wouldn't have got otherwise see you + + align:start position:0% +wouldn't have got otherwise see you + + + align:start position:0% +wouldn't have got otherwise see you +tomorrow + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/1eIFnKOZ-oY.txt b/1eIFnKOZ-oY.txt new file mode 100644 index 0000000000000000000000000000000000000000..9fe8177d77a03f2965c94cd18959a50fc29599ed --- /dev/null +++ b/1eIFnKOZ-oY.txt @@ -0,0 +1,340 @@ +In this lecture you'll learn various techniques +for creating combinational logic circuits + +that implement a particular functional specification. + +A functional specification is part of the +static discipline we use to create the combinational + +logic abstraction of a circuit. + +One approach is to use natural language to +describe the operation of a device. + +This approach has its pros and cons. + +In its favor, natural language can convey +complicated concepts in surprisingly compact + +form and it is a notation that most of us +know how to read and understand. + +But, unless the words are very carefully crafted, +there may be ambiguities introduced by words + +with multiple interpretations or by lack of +completeness since it's not always obvious + +whether all eventualities have been dealt +with. + +There are good alternatives that address the +shortcomings mentioned above. + +Truth tables are a straightforward tabular +representation that specifies the values of + +the outputs for each possible combination +of the digital inputs. + +If a device has N digital inputs, its truth +table will have 2^N rows. + +In the example shown here, the device has +3 inputs, each of which can have the value + +0 or the value 1. + +There are 2*2*2 = 2^3 = 8 combinations of +the three input values, so there are 8 rows + +in the truth table. + +It's straightforward to systematically enumerate +the 8 combinations, which makes it easy to + +ensure that no combination is omitted when +building the specification. + +And since the output values are specified +explicitly, there isn't much room for misinterpreting + +the desired functionality! + +Truth tables are an excellent choice for devices +with small numbers of inputs and outputs. + +Sadly, they aren't really practical when the +devices have many inputs. + +If, for example, we were describing the functionality +of a circuit to add two 32-bit numbers, there + +would be 64 inputs altogether and the truth +table would need 2^64 rows. + +Hmm, not sure how practical that is! + +If we entered the correct output value for +a row once per second, it would take 584 billion + +years to fill in the table! + +Another alternative specification is to use +Boolean equations to describe how to compute + +the output values from the input values using +Boolean algebra. + +The operations we use are the logical operations +AND, OR, and XOR, each of which takes two + +Boolean operands, and NOT which takes a single +Boolean operand. + +Using the truth tables that describe these +logical operations, it's straightforward to + +compute an output value from a particular +combination of input values using the sequence + +of operations laid out in the equation. + +Let me say a quick word about the notation +used for Boolean equations. + +Input values are represented by the name of +the input, in this example one of "A", "B", + +or "C". + +The digital input value 0 is equivalent to +the Boolean value FALSE and the digital input + +value 1 is equivalent to the Boolean value +TRUE. + +The Boolean operation NOT is indicated by +a horizontal line drawn above a Boolean expression. + +In this example, the first symbol following +the equal sign is a "C" with line above it, + +indicating that the value of C should be inverted +before it's used in evaluating the rest of + +the expression. + +The Boolean operation AND is represented by +the multiplication operation using standard + +mathematical notation. + +Sometimes we'll use an explicit multiplication +operator - usually written as a dot between + +two Boolean expressions - as shown in the +first term of the example equation. + +Sometimes the AND operator is implicit as +shown in the remaining three terms of the + +example equation. + +The Boolean operation OR is represented by +the addition operation, always shown as a + +"+" sign. + +Boolean equations are useful when the device +has many inputs. + +And, as we'll see, it's easy to convert a +Boolean equation into a circuit schematic. + +Truth tables and Boolean equations are interchangeable. + +If we have a Boolean equation for each output, +we can fill in the output columns for a row + +of the truth table by evaluating the Boolean +equations using the particular combination + +of input values for that row. + +For example, to determine the value for Y +in the first row of the truth table, we'd + +substitute the Boolean value FALSE for the +symbols A, B, and C in the equation and then + +use Boolean algebra to compute the result. + +We can go the other way too. + +We can always convert a truth table into a +particular form of Boolean equation called + +a sum-of-products. + +Let's see how… + +Start by looking at the truth table and answering +the question "When does Y have the value 1?" + +Or, in the language of Boolean algebra: "When +is Y TRUE?". + +Well, Y is TRUE when the inputs correspond +to row 2 of the truth table, OR to row 4, + +OR to rows 7 OR 8. + +Altogether there are 4 combinations of inputs +for which Y is TRUE. + +The corresponding Boolean equation thus is +the OR for four terms, where each term is + +a boolean expression which evaluates to TRUE +for a particular combination of inputs. + +Row 2 of the truth table corresponds to C=0, +B=0, and A=1. + +The corresponding Boolean expression is (NOT +C) AND (NOT B) + +AND A, an expression that evaluates to TRUE +if and only if C is 0, B is 0, and A is 1. + +The boolean expression corresponding to row +4 is (NOT C) AND B AND A. + +And so on for rows 7 and 8. + +The approach will always give us an expression +in the form of a sum-of-products. + +"Sum" refers to the OR operations and "products" +refers to the groups of AND operations. + +In this example we have the sum of four product +terms. + +Our next step is to use the Boolean expression +as a recipe for constructing a circuit implementation + +using combinational logic gates. + +As circuit designers we'll be working with +a library of combinational logic gates, which + +either is given to us by the integrated circuit +manufacturer, or which we've designed ourselves + +as CMOS gates using NFET and PFET switches. + +One of the simplest gates is the inverter, +which has the schematic symbol shown here. + +The small circle on the output wire indicates +an inversion, a common convention used in + +schematics. + +We can see from its truth table that the inverter +implements the Boolean NOT function. + +The AND gate outputs 1 if and only if the +A input is 1 *and* the B input is 1, hence + +the name "AND". + +The library will usually include AND gates +with 3 inputs, 4 inputs, etc., which produce + +a 1 output if and only if all of their inputs +are 1. + +The OR gate outputs 1 if the A input is 1 +*or* if the B input is 1, hence the name "OR". + +Again, the library will usually include OR +gates with 3 inputs, 4 inputs, etc., which + +produce a 1 output when at least one of their +inputs is 1. + +These are the standard schematic symbols for +AND and OR gates. + +Note that the AND symbol is straight on the +input side, while the OR symbol is curved. + +With a little practice, you'll find it easy +to remember which schematic symbols are which. + +Now let's use these building blocks to build +a circuit that implements a sum-of-products + +equation. + +The structure of the circuit exactly follows +the structure of the Boolean equation. + +We use inverters to perform the necessary +Boolean NOT operations. + +In a sum-of-products equation the inverters +are operating on particular input values, + +in this case A, B and C. +To keep the schematic easy to read we've used + +a separate inverter for each of the four NOT +operations in the Boolean equation, but in + +real life we might invert the C input once +to produce a NOT-C signal, then use that signal + +whenever a NOT-C value is needed. + +Each of the four product terms is built using +a 3-input AND gate. + +And the product terms are ORed together using +a 4-input OR gate. + +The final circuit has a layer of inverters, +a layer of AND gates and final OR gate. + +In the next section we'll talk about how to +build AND or OR gates with many inputs from + +library components with fewer inputs. + +The propagation delay for a sum-of-products +circuit looks pretty short: the longest path + +from inputs to outputs includes an inverter, +an AND gate and an OR gate. + +Can we really implement any Boolean equation +in a circuit with a tPD of three gate delays? + +Actually not, since building ANDs and ORs +with many inputs will require additional layers + +of components, which will increase the propagation +delay. + +We'll learn about this in the next section. + +The good news is that we now have straightforward +techniques for converting a truth table to + +its corresponding sum-of-products Boolean +equation, and for building a circuit that + +implements that equation. \ No newline at end of file diff --git a/41ee6EsHchA.txt b/41ee6EsHchA.txt new file mode 100644 index 0000000000000000000000000000000000000000..14d9d6378895ed05345c379cb3e9323c80252417 --- /dev/null +++ b/41ee6EsHchA.txt @@ -0,0 +1,2787 @@ +align:start position:0% + +okay so that's our introduction to the + + align:start position:0% +okay so that's our introduction to the + + + align:start position:0% +okay so that's our introduction to the +subject now we have to get going with to + + align:start position:0% +subject now we have to get going with to + + + align:start position:0% +subject now we have to get going with to +explore how to set up the scattering + + align:start position:0% +explore how to set up the scattering + + + align:start position:0% +explore how to set up the scattering +problem so equations that we need to + + align:start position:0% +problem so equations that we need to + + + align:start position:0% +problem so equations that we need to +solve well what are the equations we + + align:start position:0% +solve well what are the equations we + + + align:start position:0% +solve well what are the equations we +will have a Hamiltonian just P squared + + align:start position:0% +will have a Hamiltonian just P squared + + + align:start position:0% +will have a Hamiltonian just P squared +over 2m plus a potential V of R need not + + align:start position:0% +over 2m plus a potential V of R need not + + + align:start position:0% +over 2m plus a potential V of R need not +be yet a central potential as usual we + + align:start position:0% +be yet a central potential as usual we + + + align:start position:0% +be yet a central potential as usual we +will think of a wave function that + + align:start position:0% +will think of a wave function that + + + align:start position:0% +will think of a wave function that +depends on R and T that will be written + + align:start position:0% +depends on R and T that will be written + + + align:start position:0% +depends on R and T that will be written +a subside that depends on R times e to + + align:start position:0% +a subside that depends on R times e to + + + align:start position:0% +a subside that depends on R times e to +the minus I R an energy eigenstate and + + align:start position:0% +the minus I R an energy eigenstate and + + + align:start position:0% +the minus I R an energy eigenstate and +then the equation that you have to solve + + align:start position:0% +then the equation that you have to solve + + + align:start position:0% +then the equation that you have to solve +the time independent independent + + align:start position:0% +the time independent independent + + + align:start position:0% +the time independent independent +Schrodinger equation becomes minus H + + align:start position:0% +Schrodinger equation becomes minus H + + + align:start position:0% +Schrodinger equation becomes minus H +squared over 2m laplacian plus VF are + + align:start position:0% + + + + align:start position:0% + +acting on so far is equal to e Phi of R + + align:start position:0% +acting on so far is equal to e Phi of R + + + align:start position:0% +acting on so far is equal to e Phi of R +so these are the equations that you have + + align:start position:0% +so these are the equations that you have + + + align:start position:0% +so these are the equations that you have +seen already endlessly in quantum + + align:start position:0% +seen already endlessly in quantum + + + align:start position:0% +seen already endlessly in quantum +mechanics these are equations we write + + align:start position:0% +mechanics these are equations we write + + + align:start position:0% +mechanics these are equations we write +to get warmed up and we just repeat for + + align:start position:0% +to get warmed up and we just repeat for + + + align:start position:0% +to get warmed up and we just repeat for +ourselves that we have a Hamiltonian in + + align:start position:0% +ourselves that we have a Hamiltonian in + + + align:start position:0% +ourselves that we have a Hamiltonian in +the picture where the particles are + + align:start position:0% +the picture where the particles are + + + align:start position:0% +the picture where the particles are +scattering off of a central potential + + align:start position:0% +scattering off of a central potential + + + align:start position:0% +scattering off of a central potential +not a potential a central potential in + + align:start position:0% +not a potential a central potential in + + + align:start position:0% +not a potential a central potential in +fact just off of a potential work with + + align:start position:0% +fact just off of a potential work with + + + align:start position:0% +fact just off of a potential work with +energy eigenstates and these are going + + align:start position:0% +energy eigenstates and these are going + + + align:start position:0% +energy eigenstates and these are going +to be the equation for the energy + + align:start position:0% +to be the equation for the energy + + + align:start position:0% +to be the equation for the energy +eigenstates now let's write the first + + align:start position:0% +eigenstates now let's write the first + + + align:start position:0% +eigenstates now let's write the first +picture of our picture of the scattering + + align:start position:0% +picture of our picture of the scattering + + + align:start position:0% +picture of our picture of the scattering +process + + align:start position:0% +process + + + align:start position:0% +process +is some sort of target here or potential + + align:start position:0% +is some sort of target here or potential + + + align:start position:0% +is some sort of target here or potential +and particles that come in and scatter + + align:start position:0% +and particles that come in and scatter + + + align:start position:0% +and particles that come in and scatter +off of this potential so we're looking + + align:start position:0% +off of this potential so we're looking + + + align:start position:0% +off of this potential so we're looking +for energy eigenstates and we will try + + align:start position:0% +for energy eigenstates and we will try + + + align:start position:0% +for energy eigenstates and we will try +to identify our energy eigenstates and + + align:start position:0% +to identify our energy eigenstates and + + + align:start position:0% +to identify our energy eigenstates and +what we're gonna see is that this + + align:start position:0% +what we're gonna see is that this + + + align:start position:0% +what we're gonna see is that this +potential is finite range as well range + + align:start position:0% + + + + align:start position:0% + +finite range we can deal with potentials + + align:start position:0% +finite range we can deal with potentials + + + align:start position:0% +finite range we can deal with potentials +that fall off relatively fast already + + align:start position:0% +that fall off relatively fast already + + + align:start position:0% +that fall off relatively fast already +the Coulomb potential doesn't fall off + + align:start position:0% +the Coulomb potential doesn't fall off + + + align:start position:0% +the Coulomb potential doesn't fall off +that fast but potentials that fall + + align:start position:0% +that fast but potentials that fall + + + align:start position:0% +that fast but potentials that fall +faster than the Coulomb potential + + align:start position:0% +faster than the Coulomb potential + + + align:start position:0% +faster than the Coulomb potential +potentially they're just localized which + + align:start position:0% +potentially they're just localized which + + + align:start position:0% +potentially they're just localized which +is it's pretty common if you have an + + align:start position:0% +is it's pretty common if you have an + + + align:start position:0% +is it's pretty common if you have an +atom and you scatter things off of it if + + align:start position:0% +atom and you scatter things off of it if + + + align:start position:0% +atom and you scatter things off of it if +it's a neutral atom the potential due to + + align:start position:0% +it's a neutral atom the potential due to + + + align:start position:0% +it's a neutral atom the potential due to +the atom is zero outside the atom but as + + align:start position:0% +the atom is zero outside the atom but as + + + align:start position:0% +the atom is zero outside the atom but as +soon as you go inside the atom you start + + align:start position:0% +soon as you go inside the atom you start + + + align:start position:0% +soon as you go inside the atom you start +experiences all the electric forces that + + align:start position:0% +experiences all the electric forces that + + + align:start position:0% +experiences all the electric forces that +are due to the nucleus and the electrons + + align:start position:0% +are due to the nucleus and the electrons + + + align:start position:0% +are due to the nucleus and the electrons +so a finite range potential and we're + + align:start position:0% +so a finite range potential and we're + + + align:start position:0% +so a finite range potential and we're +going to think of solutions that okay + + align:start position:0% +going to think of solutions that okay + + + align:start position:0% +going to think of solutions that okay +away from the finite range are plane + + align:start position:0% +away from the finite range are plane + + + align:start position:0% +away from the finite range are plane +waves solutions of constant energy + + align:start position:0% +waves solutions of constant energy + + + align:start position:0% +waves solutions of constant energy +specified with perhaps some momentum so + + align:start position:0% +specified with perhaps some momentum so + + + align:start position:0% +specified with perhaps some momentum so +we will think of E as H squared K + + align:start position:0% +we will think of E as H squared K + + + align:start position:0% +we will think of E as H squared K +squared over 2m this is a way of + + align:start position:0% +squared over 2m this is a way of + + + align:start position:0% +squared over 2m this is a way of +thinking of the energy of a given energy + + align:start position:0% +thinking of the energy of a given energy + + + align:start position:0% +thinking of the energy of a given energy +eigenstate so it's another label for the + + align:start position:0% +eigenstate so it's another label for the + + + align:start position:0% +eigenstate so it's another label for the +energy this one it looks like I've done + + align:start position:0% +energy this one it looks like I've done + + + align:start position:0% +energy this one it looks like I've done +something but I haven't done much except + + align:start position:0% +something but I haven't done much except + + + align:start position:0% +something but I haven't done much except +to begin an in equation process in your + + align:start position:0% +to begin an in equation process in your + + + align:start position:0% +to begin an in equation process in your +head in which somehow these are going to + + align:start position:0% +head in which somehow these are going to + + + align:start position:0% +head in which somehow these are going to +be related to energy eigenstates that + + align:start position:0% +be related to energy eigenstates that + + + align:start position:0% +be related to energy eigenstates that +have some momentum as they propagate all + + align:start position:0% +have some momentum as they propagate all + + + align:start position:0% +have some momentum as they propagate all +over space so if I ride that I can just + + align:start position:0% +over space so if I ride that I can just + + + align:start position:0% +over space so if I ride that I can just +simply put this on the left-hand side + + align:start position:0% +simply put this on the left-hand side + + + align:start position:0% +simply put this on the left-hand side +and get an equation that it's kind of + + align:start position:0% +and get an equation that it's kind of + + + align:start position:0% +and get an equation that it's kind of +nicer minus H squared over 2m laplacian + + align:start position:0% +nicer minus H squared over 2m laplacian + + + align:start position:0% +nicer minus H squared over 2m laplacian +square plus K squared plus VFR sIFR + + align:start position:0% +square plus K squared plus VFR sIFR + + + align:start position:0% +square plus K squared plus VFR sIFR +equals zero + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +okay it's not really a matter scattering + + align:start position:0% +okay it's not really a matter scattering + + + align:start position:0% +okay it's not really a matter scattering +up of solving this equation at this + + align:start position:0% +up of solving this equation at this + + + align:start position:0% +up of solving this equation at this +moment infinitely many solutions of this + + align:start position:0% +moment infinitely many solutions of this + + + align:start position:0% +moment infinitely many solutions of this +equation and most of them may not be + + align:start position:0% +equation and most of them may not be + + + align:start position:0% +equation and most of them may not be +relevant for us we're not trying to find + + align:start position:0% +relevant for us we're not trying to find + + + align:start position:0% +relevant for us we're not trying to find +every solution of this equation we're + + align:start position:0% +every solution of this equation we're + + + align:start position:0% +every solution of this equation we're +trying to find solutions that have + + align:start position:0% +trying to find solutions that have + + + align:start position:0% +trying to find solutions that have +something to do with the physics and + + align:start position:0% +something to do with the physics and + + + align:start position:0% +something to do with the physics and +you've done that when you had potentials + + align:start position:0% +you've done that when you had potentials + + + align:start position:0% +you've done that when you had potentials +in one dimension and that inclusion is + + align:start position:0% +in one dimension and that inclusion is + + + align:start position:0% +in one dimension and that inclusion is +going to prove invaluable so when you + + align:start position:0% +going to prove invaluable so when you + + + align:start position:0% +going to prove invaluable so when you +have a potential in one dimension you + + align:start position:0% +have a potential in one dimension you + + + align:start position:0% +have a potential in one dimension you +didn't say okay I'm gonna find all the + + align:start position:0% +didn't say okay I'm gonna find all the + + + align:start position:0% +didn't say okay I'm gonna find all the +energy eigenstates you you said let's + + align:start position:0% +energy eigenstates you you said let's + + + align:start position:0% +energy eigenstates you you said let's +search for things that are reasonable + + align:start position:0% +search for things that are reasonable + + + align:start position:0% +search for things that are reasonable +and physically motivated so you put in a + + align:start position:0% +and physically motivated so you put in a + + + align:start position:0% +and physically motivated so you put in a +wave that was moving in and you said + + align:start position:0% +wave that was moving in and you said + + + align:start position:0% +wave that was moving in and you said +okay this wave is a solution until it + + align:start position:0% +okay this wave is a solution until it + + + align:start position:0% +okay this wave is a solution until it +reaches this point where it just stops + + align:start position:0% +reaches this point where it just stops + + + align:start position:0% +reaches this point where it just stops +being a solution you need more if you + + align:start position:0% +being a solution you need more if you + + + align:start position:0% +being a solution you need more if you +put in this wave you will generate a + + align:start position:0% +put in this wave you will generate a + + + align:start position:0% +put in this wave you will generate a +reflected wave and a transmitted wave + + align:start position:0% +reflected wave and a transmitted wave + + + align:start position:0% +reflected wave and a transmitted wave +those two waves are gonna be generated + + align:start position:0% +those two waves are gonna be generated + + + align:start position:0% +those two waves are gonna be generated +and then you write and + + align:start position:0% +and then you write and + + + align:start position:0% +and then you write and +SATs for this wave sub coefficient a e + + align:start position:0% +SATs for this wave sub coefficient a e + + + align:start position:0% +SATs for this wave sub coefficient a e +to the ikx b e to the minus ikx e e to + + align:start position:0% +to the ikx b e to the minus ikx e e to + + + align:start position:0% +to the ikx b e to the minus ikx e e to +the other and then you solve your + + align:start position:0% +the other and then you solve your + + + align:start position:0% +the other and then you solve your +equation so we need to do the same thing + + align:start position:0% +equation so we need to do the same thing + + + align:start position:0% +equation so we need to do the same thing +with this kind of equation and this kind + + align:start position:0% +with this kind of equation and this kind + + + align:start position:0% +with this kind of equation and this kind +of potential we have to set up some sort + + align:start position:0% +of potential we have to set up some sort + + + align:start position:0% +of potential we have to set up some sort +of situation where we have the physics + + align:start position:0% +of situation where we have the physics + + + align:start position:0% +of situation where we have the physics +intuition of a wave that is coming in + + align:start position:0% +intuition of a wave that is coming in + + + align:start position:0% +intuition of a wave that is coming in +and then whatever the system will do to + + align:start position:0% +and then whatever the system will do to + + + align:start position:0% +and then whatever the system will do to +that wave to upgrade it into a full + + align:start position:0% +that wave to upgrade it into a full + + + align:start position:0% +that wave to upgrade it into a full +solution + + align:start position:0% +solution + + + align:start position:0% +solution +so that's wouldn't want to do here in + + align:start position:0% +so that's wouldn't want to do here in + + + align:start position:0% +so that's wouldn't want to do here in +analogy to that thing this could be + + align:start position:0% +analogy to that thing this could be + + + align:start position:0% +analogy to that thing this could be +called incoming wave and this whole + + align:start position:0% +called incoming wave and this whole + + + align:start position:0% +called incoming wave and this whole +thing the reflected and the transmitted + + align:start position:0% +thing the reflected and the transmitted + + + align:start position:0% +thing the reflected and the transmitted +could be called the scattered wave the + + align:start position:0% +could be called the scattered wave the + + + align:start position:0% +could be called the scattered wave the +thing that gets produced by the + + align:start position:0% +thing that gets produced by the + + + align:start position:0% +thing that gets produced by the +scattering process so if you had there's + + align:start position:0% +scattering process so if you had there's + + + align:start position:0% +scattering process so if you had there's +a lot of solutions of that equation if B + + align:start position:0% +a lot of solutions of that equation if B + + + align:start position:0% +a lot of solutions of that equation if B +was identically 0 if you had no + + align:start position:0% +was identically 0 if you had no + + + align:start position:0% +was identically 0 if you had no +potential you could have lots of + + align:start position:0% +potential you could have lots of + + + align:start position:0% +potential you could have lots of +solutions because in fact if the + + align:start position:0% +solutions because in fact if the + + + align:start position:0% +solutions because in fact if the +potential is not zero plane waves are + + align:start position:0% +potential is not zero plane waves are + + + align:start position:0% +potential is not zero plane waves are +always solutions without any potential + + align:start position:0% +always solutions without any potential + + + align:start position:0% +always solutions without any potential +particles that move as plane wave so if + + align:start position:0% +particles that move as plane wave so if + + + align:start position:0% +particles that move as plane wave so if +we equals zero plane waves of the farm + + align:start position:0% +we equals zero plane waves of the farm + + + align:start position:0% +we equals zero plane waves of the farm +side equal e to the I K X are solutions + + align:start position:0% + + + + align:start position:0% + +with k equal the square root of K dot k + + align:start position:0% + + + + align:start position:0% + +or with K squared equal K dot K plane + + align:start position:0% +or with K squared equal K dot K plane + + + align:start position:0% +or with K squared equal K dot K plane +waves are always solutions of these + + align:start position:0% +waves are always solutions of these + + + align:start position:0% +waves are always solutions of these +equations + + align:start position:0% + + + + align:start position:0% + +so if plane waves are solutions of this + + align:start position:0% +so if plane waves are solutions of this + + + align:start position:0% +so if plane waves are solutions of this +equation for V equal to zero this is the + + align:start position:0% +equation for V equal to zero this is the + + + align:start position:0% +equation for V equal to zero this is the +same thing as saying here that a e to + + align:start position:0% +same thing as saying here that a e to + + + align:start position:0% +same thing as saying here that a e to +the ikx + + align:start position:0% +the ikx + + + align:start position:0% +the ikx +is a solution of this equation as long + + align:start position:0% +is a solution of this equation as long + + + align:start position:0% +is a solution of this equation as long +as you don't hit the potential so here + + align:start position:0% +as you don't hit the potential so here + + + align:start position:0% +as you don't hit the potential so here +we're gonna do something quite similar + + align:start position:0% +we're gonna do something quite similar + + + align:start position:0% +we're gonna do something quite similar +we're gonna say that we we're going to + + align:start position:0% +we're gonna say that we we're going to + + + align:start position:0% +we're gonna say that we we're going to +put in an incident wave function wave + + align:start position:0% +put in an incident wave function wave + + + align:start position:0% +put in an incident wave function wave +function and I will instead of writing + + align:start position:0% +function and I will instead of writing + + + align:start position:0% +function and I will instead of writing +psy I will call it Phi of X the incident + + align:start position:0% +psy I will call it Phi of X the incident + + + align:start position:0% +psy I will call it Phi of X the incident +wave function Phi of X it's going to be + + align:start position:0% +wave function Phi of X it's going to be + + + align:start position:0% +wave function Phi of X it's going to be +just e to the I K Z so it's a wave + + align:start position:0% +just e to the I K Z so it's a wave + + + align:start position:0% +just e to the I K Z so it's a wave +function I call it Phi to distinguish it + + align:start position:0% +function I call it Phi to distinguish it + + + align:start position:0% +function I call it Phi to distinguish it +from psy psy in general it's a full + + align:start position:0% +from psy psy in general it's a full + + + align:start position:0% +from psy psy in general it's a full +solution of the Schrodinger equation + + align:start position:0% +solution of the Schrodinger equation + + + align:start position:0% +solution of the Schrodinger equation +that's our understanding of psy so Phi + + align:start position:0% +that's our understanding of psy so Phi + + + align:start position:0% +that's our understanding of psy so Phi +it reminds you that well it's it's some + + align:start position:0% +it reminds you that well it's it's some + + + align:start position:0% +it reminds you that well it's it's some +wave function I'm not sure it's a + + align:start position:0% +wave function I'm not sure it's a + + + align:start position:0% +wave function I'm not sure it's a +solution in fact it probably is not a + + align:start position:0% +solution in fact it probably is not a + + + align:start position:0% +solution in fact it probably is not a +solution as soon as you have the + + align:start position:0% +solution as soon as you have the + + + align:start position:0% +solution as soon as you have the +potential different from zero so this is + + align:start position:0% +potential different from zero so this is + + + align:start position:0% +potential different from zero so this is +this common we forget the case v equals + + align:start position:0% +this common we forget the case v equals + + + align:start position:0% +this common we forget the case v equals +zero and now we put an incident wave + + align:start position:0% +zero and now we put an incident wave + + + align:start position:0% +zero and now we put an incident wave +function which is of this form the + + align:start position:0% +function which is of this form the + + + align:start position:0% +function which is of this form the +solves the equation as long as you're + + align:start position:0% +solves the equation as long as you're + + + align:start position:0% +solves the equation as long as you're +away from the potential this is true + + align:start position:0% +away from the potential this is true + + + align:start position:0% +away from the potential this is true +good it's a solution of the Schrodinger + + align:start position:0% +good it's a solution of the Schrodinger + + + align:start position:0% +good it's a solution of the Schrodinger +equation away from V of R away from B + + align:start position:0% +equation away from V of R away from B + + + align:start position:0% +equation away from V of R away from B +afar means wherever V of R is equal to + + align:start position:0% +afar means wherever V of R is equal to + + + align:start position:0% +afar means wherever V of R is equal to +zero you have a solution nevertheless so + + align:start position:0% +zero you have a solution nevertheless so + + + align:start position:0% +zero you have a solution nevertheless so +if we call the range of the potential + + align:start position:0% +if we call the range of the potential + + + align:start position:0% +if we call the range of the potential +let's call the range of the potential + + align:start position:0% +let's call the range of the potential + + + align:start position:0% +let's call the range of the potential +finite range a that is to take that if + + align:start position:0% +finite range a that is to take that if + + + align:start position:0% +finite range a that is to take that if +there's an origin here up to a radius a + + align:start position:0% +there's an origin here up to a radius a + + + align:start position:0% +there's an origin here up to a radius a +there is some potential and beyond the + + align:start position:0% +there is some potential and beyond the + + + align:start position:0% +there is some potential and beyond the +radius a the potential vanishes so this + + align:start position:0% +radius a the potential vanishes so this + + + align:start position:0% +radius a the potential vanishes so this +definitely works it's all case away from + + align:start position:0% +definitely works it's all case away from + + + align:start position:0% +definitely works it's all case away from +the R or as long as or as long as R is + + align:start position:0% +the R or as long as or as long as R is + + + align:start position:0% +the R or as long as or as long as R is +greater than a for whatever value of Z + + align:start position:0% +greater than a for whatever value of Z + + + align:start position:0% +greater than a for whatever value of Z +you take this is fine so here is our + + align:start position:0% +you take this is fine so here is our + + + align:start position:0% +you take this is fine so here is our +wave and now this is just the incident + + align:start position:0% +wave and now this is just the incident + + + align:start position:0% +wave and now this is just the incident +wave this is not gonna be the whole + + align:start position:0% +wave this is not gonna be the whole + + + align:start position:0% +wave this is not gonna be the whole +solution just like if live + + align:start position:0% +solution just like if live + + + align:start position:0% +solution just like if live +one-dimensional case there must be more + + align:start position:0% +one-dimensional case there must be more + + + align:start position:0% +one-dimensional case there must be more +so what is there more and our challenge + + align:start position:0% +so what is there more and our challenge + + + align:start position:0% +so what is there more and our challenge +to begin with this problem is to set up + + align:start position:0% +to begin with this problem is to set up + + + align:start position:0% +to begin with this problem is to set up +what else could there be + + align:start position:0% +what else could there be + + + align:start position:0% +what else could there be +so looking at it you'd say alright so + + align:start position:0% +so looking at it you'd say alright so + + + align:start position:0% +so looking at it you'd say alright so +thing comes in if they're scattering is + + align:start position:0% +thing comes in if they're scattering is + + + align:start position:0% +thing comes in if they're scattering is +going to particle sometimes I'm going to + + align:start position:0% +going to particle sometimes I'm going to + + + align:start position:0% +going to particle sometimes I'm going to +go off in various directions so the + + align:start position:0% +go off in various directions so the + + + align:start position:0% +go off in various directions so the +outgoing wave here there were outgoing + + align:start position:0% +outgoing wave here there were outgoing + + + align:start position:0% +outgoing wave here there were outgoing +waves reflected and transmitted the + + align:start position:0% +waves reflected and transmitted the + + + align:start position:0% +waves reflected and transmitted the +outgoing wave in the three-dimensional + + align:start position:0% +outgoing wave in the three-dimensional + + + align:start position:0% +outgoing wave in the three-dimensional +scaring problem should be some sort of + + align:start position:0% +scaring problem should be some sort of + + + align:start position:0% +scaring problem should be some sort of +spherical wave + + align:start position:0% +spherical wave + + + align:start position:0% +spherical wave +being away from our equal 0 which is the + + align:start position:0% +being away from our equal 0 which is the + + + align:start position:0% +being away from our equal 0 which is the +origin that should be the other way that + + align:start position:0% +origin that should be the other way that + + + align:start position:0% +origin that should be the other way that +I would write so my answers should be + + align:start position:0% +I would write so my answers should be + + + align:start position:0% +I would write so my answers should be +that there's some sort of spherical wave + + align:start position:0% +that there's some sort of spherical wave + + + align:start position:0% +that there's some sort of spherical wave +that is moving away so to complete this + + align:start position:0% + + + + align:start position:0% + +with a spherical outgoing wave so while + + align:start position:0% +with a spherical outgoing wave so while + + + align:start position:0% +with a spherical outgoing wave so while +here this is a plane wave moving in the + + align:start position:0% +here this is a plane wave moving in the + + + align:start position:0% +here this is a plane wave moving in the +direction of the vector K if I want to + + align:start position:0% +direction of the vector K if I want to + + + align:start position:0% +direction of the vector K if I want to +write the spherical wave I would write e + + align:start position:0% +write the spherical wave I would write e + + + align:start position:0% +write the spherical wave I would write e +to the I just K R e to the IKr is + + align:start position:0% +to the I just K R e to the IKr is + + + align:start position:0% +to the I just K R e to the IKr is +spherically symmetric and it propagates + + align:start position:0% +spherically symmetric and it propagates + + + align:start position:0% +spherically symmetric and it propagates +radially out if you remember as usual + + align:start position:0% +radially out if you remember as usual + + + align:start position:0% +radially out if you remember as usual +that you have e to the minus I in T over + + align:start position:0% +that you have e to the minus I in T over + + + align:start position:0% +that you have e to the minus I in T over +H bar so you have km R minus ET that is + + align:start position:0% +H bar so you have km R minus ET that is + + + align:start position:0% +H bar so you have km R minus ET that is +a wave that propagates radially out so + + align:start position:0% +a wave that propagates radially out so + + + align:start position:0% +a wave that propagates radially out so +maybe this is kind of this scattered + + align:start position:0% +maybe this is kind of this scattered + + + align:start position:0% +maybe this is kind of this scattered +wave this e to the IKr moving out + + align:start position:0% +wave this e to the IKr moving out + + + align:start position:0% +wave this e to the IKr moving out +everywhere would be your scattered wave + + align:start position:0% + + + + align:start position:0% + +if that is a scattered wave remember we + + align:start position:0% +if that is a scattered wave remember we + + + align:start position:0% +if that is a scattered wave remember we +should the scattered wave should solve + + align:start position:0% +should the scattered wave should solve + + + align:start position:0% +should the scattered wave should solve +the Schrodinger equation in fact the sum + + align:start position:0% +the Schrodinger equation in fact the sum + + + align:start position:0% +the Schrodinger equation in fact the sum +of these two should solve the scattering + + align:start position:0% +of these two should solve the scattering + + + align:start position:0% +of these two should solve the scattering +equation on the other hand we've seen + + align:start position:0% +equation on the other hand we've seen + + + align:start position:0% +equation on the other hand we've seen +that this solves it as long as you're + + align:start position:0% +that this solves it as long as you're + + + align:start position:0% +that this solves it as long as you're +away from the potential and therefore + + align:start position:0% +away from the potential and therefore + + + align:start position:0% +away from the potential and therefore +this should also solve it if you're away + + align:start position:0% +this should also solve it if you're away + + + align:start position:0% +this should also solve it if you're away +from the potential so I ask you do you + + align:start position:0% +from the potential so I ask you do you + + + align:start position:0% +from the potential so I ask you do you +think this solve the Schrodinger + + align:start position:0% +think this solve the Schrodinger + + + align:start position:0% +think this solve the Schrodinger +equation when you're away from the + + align:start position:0% +equation when you're away from the + + + align:start position:0% +equation when you're away from the +potential + + align:start position:0% + + + + align:start position:0% + +would eat to the IKr solve the equation + + align:start position:0% +would eat to the IKr solve the equation + + + align:start position:0% +would eat to the IKr solve the equation +but for that you would need that if + + align:start position:0% +but for that you would need that if + + + align:start position:0% +but for that you would need that if +you're away from the potential do you + + align:start position:0% +you're away from the potential do you + + + align:start position:0% +you're away from the potential do you +have laplacian of e to the IKr roughly + + align:start position:0% +have laplacian of e to the IKr roughly + + + align:start position:0% +have laplacian of e to the IKr roughly +equals zero is that true + + align:start position:0% + + + + align:start position:0% + +will it solve it no it doesn't solve it + + align:start position:0% +will it solve it no it doesn't solve it + + + align:start position:0% +will it solve it no it doesn't solve it +doesn't even come close to solving it + + align:start position:0% +doesn't even come close to solving it + + + align:start position:0% +doesn't even come close to solving it +it's pretty bad but the reason it's bad + + align:start position:0% +it's pretty bad but the reason it's bad + + + align:start position:0% +it's pretty bad but the reason it's bad +is physically clear this wave as it + + align:start position:0% +is physically clear this wave as it + + + align:start position:0% +is physically clear this wave as it +expands out must become weaker and + + align:start position:0% +expands out must become weaker and + + + align:start position:0% +expands out must become weaker and +weaker so that the probability flux + + align:start position:0% +weaker so that the probability flux + + + align:start position:0% +weaker so that the probability flux +remains constant you know you don't want + + align:start position:0% +remains constant you know you don't want + + + align:start position:0% +remains constant you know you don't want +an accumulation of probability between a + + align:start position:0% +an accumulation of probability between a + + + align:start position:0% +an accumulation of probability between a +shell at 1 kilometer and a shell at 2 + + align:start position:0% +shell at 1 kilometer and a shell at 2 + + + align:start position:0% +shell at 1 kilometer and a shell at 2 +kilometer so whatever flux is going out + + align:start position:0% +kilometer so whatever flux is going out + + + align:start position:0% +kilometer so whatever flux is going out +from the shell in one kilometer should + + align:start position:0% +from the shell in one kilometer should + + + align:start position:0% +from the shell in one kilometer should +be going out of the bigger shell so + + align:start position:0% +be going out of the bigger shell so + + + align:start position:0% +be going out of the bigger shell so +therefore it should fall off with our oh + + align:start position:0% +therefore it should fall off with our oh + + + align:start position:0% +therefore it should fall off with our oh +I'm sorry I I didn't write this well so + + align:start position:0% +I'm sorry I I didn't write this well so + + + align:start position:0% +I'm sorry I I didn't write this well so +if you are gonna have this to be a + + align:start position:0% +if you are gonna have this to be a + + + align:start position:0% +if you are gonna have this to be a +solution of the Schrodinger equation + + align:start position:0% +solution of the Schrodinger equation + + + align:start position:0% +solution of the Schrodinger equation +outside of VR equals 0 you should have + + align:start position:0% +outside of VR equals 0 you should have + + + align:start position:0% +outside of VR equals 0 you should have +laplacian plus K squared of this thing + + align:start position:0% +laplacian plus K squared of this thing + + + align:start position:0% +laplacian plus K squared of this thing +equal to 0 so if this is equal to 0 and + + align:start position:0% +equal to 0 so if this is equal to 0 and + + + align:start position:0% +equal to 0 so if this is equal to 0 and +the potential is equal to 0 the whole + + align:start position:0% +the potential is equal to 0 the whole + + + align:start position:0% +the potential is equal to 0 the whole +thing is equal to 0 so we need this to + + align:start position:0% +thing is equal to 0 so we need this to + + + align:start position:0% +thing is equal to 0 so we need this to +how + + align:start position:0% +how + + + align:start position:0% +how +but even this one of course is not true + + align:start position:0% +but even this one of course is not true + + + align:start position:0% +but even this one of course is not true +it's just absolutely not true the one + + align:start position:0% +it's just absolutely not true the one + + + align:start position:0% +it's just absolutely not true the one +that works is the following laplacian + + align:start position:0% +that works is the following laplacian + + + align:start position:0% +that works is the following laplacian +plus K squared of e to the IKr over R is + + align:start position:0% +plus K squared of e to the IKr over R is + + + align:start position:0% +plus K squared of e to the IKr over R is +equal to 0 for our different from 0 this + + align:start position:0% +equal to 0 for our different from 0 this + + + align:start position:0% +equal to 0 for our different from 0 this +is a computation I think you guys have + + align:start position:0% +is a computation I think you guys have + + + align:start position:0% +is a computation I think you guys have +done before when you were studying the + + align:start position:0% +done before when you were studying the + + + align:start position:0% +done before when you were studying the +hermeticity of P squared you ended up + + align:start position:0% +hermeticity of P squared you ended up + + + align:start position:0% +hermeticity of P squared you ended up +doing this kind of things this laplacian + + align:start position:0% +doing this kind of things this laplacian + + + align:start position:0% +doing this kind of things this laplacian +produces a delta function at R equals 0 + + align:start position:0% +produces a delta function at R equals 0 + + + align:start position:0% +produces a delta function at R equals 0 +but R equals 0 is not the place we're + + align:start position:0% +but R equals 0 is not the place we're + + + align:start position:0% +but R equals 0 is not the place we're +interested in we're trying to find how + + align:start position:0% +interested in we're trying to find how + + + align:start position:0% +interested in we're trying to find how +the waves look away from the scattering + + align:start position:0% +the waves look away from the scattering + + + align:start position:0% +the waves look away from the scattering +Center + + align:start position:0% +Center + + + align:start position:0% +Center +so we need this to hold away from our + + align:start position:0% +so we need this to hold away from our + + + align:start position:0% +so we need this to hold away from our +equals zero in fact bigger for our + + align:start position:0% +equals zero in fact bigger for our + + + align:start position:0% +equals zero in fact bigger for our +bigger than a and one way of checking + + align:start position:0% +bigger than a and one way of checking + + + align:start position:0% +bigger than a and one way of checking +this kind of thing is to remember that + + align:start position:0% +this kind of thing is to remember that + + + align:start position:0% +this kind of thing is to remember that +the laplacian of a function of r is in + + align:start position:0% +the laplacian of a function of r is in + + + align:start position:0% +the laplacian of a function of r is in +fact 1 over r v ii we r squared r times + + align:start position:0% +fact 1 over r v ii we r squared r times + + + align:start position:0% +fact 1 over r v ii we r squared r times +F that's a neat formula for the + + align:start position:0% +F that's a neat formula for the + + + align:start position:0% +F that's a neat formula for the +laplacian of a function that just + + align:start position:0% +laplacian of a function that just + + + align:start position:0% +laplacian of a function that just +depends on R if it depends on theta and + + align:start position:0% +depends on R if it depends on theta and + + + align:start position:0% +depends on R if it depends on theta and +Phi is more complicated but with this + + align:start position:0% +Phi is more complicated but with this + + + align:start position:0% +Phi is more complicated but with this +function it becomes a one-line + + align:start position:0% +function it becomes a one-line + + + align:start position:0% +function it becomes a one-line +calculation to do this and the R here is + + align:start position:0% +calculation to do this and the R here is + + + align:start position:0% +calculation to do this and the R here is +just fantastic because by the time you + + align:start position:0% +just fantastic because by the time you + + + align:start position:0% +just fantastic because by the time you +multiplied by R this function is just + + align:start position:0% +multiplied by R this function is just + + + align:start position:0% +multiplied by R this function is just +exponential you take two derivatives you + + align:start position:0% +exponential you take two derivatives you + + + align:start position:0% +exponential you take two derivatives you +get minus K squared and then the R gets + + align:start position:0% +get minus K squared and then the R gets + + + align:start position:0% +get minus K squared and then the R gets +cancelled as well and everything works + + align:start position:0% +cancelled as well and everything works + + + align:start position:0% +cancelled as well and everything works +beautifully here and so this equation + + align:start position:0% +beautifully here and so this equation + + + align:start position:0% +beautifully here and so this equation +holds ok and then we do have a possible + + align:start position:0% +holds ok and then we do have a possible + + + align:start position:0% +holds ok and then we do have a possible +scattered wave so we are almost there + + align:start position:0% +scattered wave so we are almost there + + + align:start position:0% +scattered wave so we are almost there +we can write the scattering wave size + + align:start position:0% +we can write the scattering wave size + + + align:start position:0% +we can write the scattering wave size +scattering scattering of X could be e to + + align:start position:0% +scattering scattering of X could be e to + + + align:start position:0% +scattering scattering of X could be e to +the I K R over R and then leave it at + + align:start position:0% +the I K R over R and then leave it at + + + align:start position:0% +the I K R over R and then leave it at +that but this would not be general + + align:start position:0% +that but this would not be general + + + align:start position:0% +that but this would not be general +enough there's no reason why this wave + + align:start position:0% +enough there's no reason why this wave + + + align:start position:0% +enough there's no reason why this wave +would not depend also on theta and Phi + + align:start position:0% + + + + align:start position:0% + +here is the Z direction and there's + + align:start position:0% +here is the Z direction and there's + + + align:start position:0% +here is the Z direction and there's +points with angle theta and if you + + align:start position:0% +points with angle theta and if you + + + align:start position:0% +points with angle theta and if you +rotate it with some angle Phi here + + align:start position:0% +rotate it with some angle Phi here + + + align:start position:0% +rotate it with some angle Phi here +and therefore this function could as + + align:start position:0% +and therefore this function could as + + + align:start position:0% +and therefore this function could as +well depend on theta and Phi so we'll + + align:start position:0% +well depend on theta and Phi so we'll + + + align:start position:0% +well depend on theta and Phi so we'll +include that factor f of theta and Phi + + align:start position:0% + + + + align:start position:0% + +now you would say look you have a nice + + align:start position:0% +now you would say look you have a nice + + + align:start position:0% +now you would say look you have a nice +solution of the Schrodinger equation + + align:start position:0% +solution of the Schrodinger equation + + + align:start position:0% +solution of the Schrodinger equation +already here and and what what should + + align:start position:0% +already here and and what what should + + + align:start position:0% +already here and and what what should +you be doing why do you add this factor + + align:start position:0% +you be doing why do you add this factor + + + align:start position:0% +you be doing why do you add this factor +with this factor it may not be any more + + align:start position:0% +with this factor it may not be any more + + + align:start position:0% +with this factor it may not be any more +a solution of the Schrodinger equation + + align:start position:0% +a solution of the Schrodinger equation + + + align:start position:0% +a solution of the Schrodinger equation +it's changing the equation and I have a + + align:start position:0% +it's changing the equation and I have a + + + align:start position:0% +it's changing the equation and I have a +laplacian and it's gonna be more + + align:start position:0% +laplacian and it's gonna be more + + + align:start position:0% +laplacian and it's gonna be more +complicated well this is true and we + + align:start position:0% +complicated well this is true and we + + + align:start position:0% +complicated well this is true and we +will see that better soon but this will + + align:start position:0% +will see that better soon but this will + + + align:start position:0% +will see that better soon but this will +remain an approximate solution for are + + align:start position:0% +remain an approximate solution for are + + + align:start position:0% +remain an approximate solution for are +much bigger than a is the leading term + + align:start position:0% +much bigger than a is the leading term + + + align:start position:0% +much bigger than a is the leading term +of a solution leaving term solution + + align:start position:0% + + + + align:start position:0% + +so if you have a leading in terms of a + + align:start position:0% +so if you have a leading in terms of a + + + align:start position:0% +so if you have a leading in terms of a +solution here this is all you want you + + align:start position:0% +solution here this is all you want you + + + align:start position:0% +solution here this is all you want you +are working at are much bigger than a + + align:start position:0% +are working at are much bigger than a + + + align:start position:0% +are working at are much bigger than a +and your whole wave and finally be + + align:start position:0% +and your whole wave and finally be + + + align:start position:0% +and your whole wave and finally be +written so your full wave sigh of or + + align:start position:0% +written so your full wave sigh of or + + + align:start position:0% +written so your full wave sigh of or +your full energy eigenstate sigh of aren + + align:start position:0% +your full energy eigenstate sigh of aren + + + align:start position:0% +your full energy eigenstate sigh of aren +t is going to be equal approximately + + align:start position:0% +t is going to be equal approximately + + + align:start position:0% +t is going to be equal approximately +equal to e to the I K well I'll write it + + align:start position:0% +equal to e to the I K well I'll write it + + + align:start position:0% +equal to e to the I K well I'll write it +this way Phi of R that incident wave + + align:start position:0% +this way Phi of R that incident wave + + + align:start position:0% +this way Phi of R that incident wave +will wrote I wrote if X there I'm sorry + + align:start position:0% +will wrote I wrote if X there I'm sorry + + + align:start position:0% +will wrote I wrote if X there I'm sorry +a plus size gathering of I should beside + + align:start position:0% +a plus size gathering of I should beside + + + align:start position:0% +a plus size gathering of I should beside +X or R let's call this R and I should + + align:start position:0% +X or R let's call this R and I should + + + align:start position:0% +X or R let's call this R and I should +call this R tie our precise scattering + + align:start position:0% +call this R tie our precise scattering + + + align:start position:0% +call this R tie our precise scattering +of our and it's therefore equal to e to + + align:start position:0% +of our and it's therefore equal to e to + + + align:start position:0% +of our and it's therefore equal to e to +the I K Z plus F of theta phi e to the I + + align:start position:0% +the I K Z plus F of theta phi e to the I + + + align:start position:0% +the I K Z plus F of theta phi e to the I +K R over R and this is only valid for + + align:start position:0% +K R over R and this is only valid for + + + align:start position:0% +K R over R and this is only valid for +our much bigger than a far away this had + + align:start position:0% +our much bigger than a far away this had + + + align:start position:0% +our much bigger than a far away this had +an analog in our problem in one + + align:start position:0% +an analog in our problem in one + + + align:start position:0% +an analog in our problem in one +dimension in one dimension you set up a + + align:start position:0% +dimension in one dimension you set up a + + + align:start position:0% +dimension in one dimension you set up a +wave and you put here the wave and + + align:start position:0% +wave and you put here the wave and + + + align:start position:0% +wave and you put here the wave and +there's a reflected wave and there's a + + align:start position:0% +there's a reflected wave and there's a + + + align:start position:0% +there's a reflected wave and there's a +transmitted wave and in setting the + + align:start position:0% +transmitted wave and in setting the + + + align:start position:0% +transmitted wave and in setting the +promised a this is valid far to the left + + align:start position:0% +promised a this is valid far to the left + + + align:start position:0% +promised a this is valid far to the left +far to the left meanings at least to the + + align:start position:0% +far to the left meanings at least to the + + + align:start position:0% +far to the left meanings at least to the +left of the barrier this is valid to the + + align:start position:0% +left of the barrier this is valid to the + + + align:start position:0% +left of the barrier this is valid to the +right and this were exact solutions in + + align:start position:0% +right and this were exact solutions in + + + align:start position:0% +right and this were exact solutions in +this region here you can't do that well + + align:start position:0% +this region here you can't do that well + + + align:start position:0% +this region here you can't do that well +but you can do reasonably well you can + + align:start position:0% +but you can do reasonably well you can + + + align:start position:0% +but you can do reasonably well you can +write solutions that are + + align:start position:0% +write solutions that are + + + align:start position:0% +write solutions that are +leading term accurate as long as you are + + align:start position:0% +leading term accurate as long as you are + + + align:start position:0% +leading term accurate as long as you are +far away so this is the first step in + + align:start position:0% +far away so this is the first step in + + + align:start position:0% +far away so this is the first step in +this whole process in which we are + + align:start position:0% +this whole process in which we are + + + align:start position:0% +this whole process in which we are +setting up the wave functions it is the + + align:start position:0% +setting up the wave functions it is the + + + align:start position:0% +setting up the wave functions it is the +most important equation this is the way + + align:start position:0% +most important equation this is the way + + + align:start position:0% +most important equation this is the way +we're going to try to find solutions now + + align:start position:0% +we're going to try to find solutions now + + + align:start position:0% +we're going to try to find solutions now +when you try to find solutions at the + + align:start position:0% +when you try to find solutions at the + + + align:start position:0% +when you try to find solutions at the +end of the day you will have to work in + + align:start position:0% +end of the day you will have to work in + + + align:start position:0% +end of the day you will have to work in +the region and are going to zero so + + align:start position:0% +the region and are going to zero so + + + align:start position:0% +the region and are going to zero so +sooner or later we'll get there but from + + align:start position:0% +sooner or later we'll get there but from + + + align:start position:0% +sooner or later we'll get there but from +the time being we we have all the + + align:start position:0% +the time being we we have all the + + + align:start position:0% +the time being we we have all the +information about what's going on far + + align:start position:0% +information about what's going on far + + + align:start position:0% +information about what's going on far +away and from there we can get most of + + align:start position:0% +away and from there we can get most of + + + align:start position:0% +away and from there we can get most of +what we need in particular this F of + + align:start position:0% +what we need in particular this F of + + + align:start position:0% +what we need in particular this F of +theta and Phi is the quantity we need to + + align:start position:0% +theta and Phi is the quantity we need to + + + align:start position:0% +theta and Phi is the quantity we need to +figure out this is all this f of theta + + align:start position:0% +figure out this is all this f of theta + + + align:start position:0% +figure out this is all this f of theta +and Phi R is called the scattering + + align:start position:0% +and Phi R is called the scattering + + + align:start position:0% +and Phi R is called the scattering +amplitude F theta and Phi or scattering + + align:start position:0% +amplitude F theta and Phi or scattering + + + align:start position:0% +amplitude F theta and Phi or scattering +and it \ No newline at end of file diff --git a/4aiTCDvlUeI.txt b/4aiTCDvlUeI.txt new file mode 100644 index 0000000000000000000000000000000000000000..9f5db597b9469526a76ffb7602dea4be401512cd --- /dev/null +++ b/4aiTCDvlUeI.txt @@ -0,0 +1,3219 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +to view additional materials from + + align:start position:0% +to view additional materials from + + + align:start position:0% +to view additional materials from +hundreds of MIT courses visit MIT open + + align:start position:0% +hundreds of MIT courses visit MIT open + + + align:start position:0% +hundreds of MIT courses visit MIT open +courseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu + + align:start position:0% +ocw.mit.edu + + + align:start position:0% +ocw.mit.edu +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +[Applause] + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +where + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +are + + align:start position:0% +are + + + align:start position:0% +are +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +so + + align:start position:0% +so + + + align:start position:0% +so +sful + + align:start position:0% +sful + + + align:start position:0% +sful +to + + align:start position:0% +to + + + align:start position:0% +to +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +[Music] + + align:start position:0% + + + + align:start position:0% + +your + + align:start position:0% +your + + + align:start position:0% +your +the was + + align:start position:0% +the was + + + align:start position:0% +the was +oh father was + + align:start position:0% +oh father was + + + align:start position:0% +oh father was +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +there the night was W with + + align:start position:0% +there the night was W with + + + align:start position:0% +there the night was W with +de + + align:start position:0% +de + + + align:start position:0% +de +the was deep and the child + + align:start position:0% + + + + align:start position:0% + +did and + + align:start position:0% +did and + + + align:start position:0% +did and +the of + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +okay it's a little bit more coordinated + + align:start position:0% +okay it's a little bit more coordinated + + + align:start position:0% +okay it's a little bit more coordinated +from me I still interestingly missed the + + align:start position:0% +from me I still interestingly missed the + + + align:start position:0% +from me I still interestingly missed the +interval uh going from the end of 27 to + + align:start position:0% +interval uh going from the end of 27 to + + + align:start position:0% +interval uh going from the end of 27 to +the beginning of 28 uh ordinarily I'm + + align:start position:0% +the beginning of 28 uh ordinarily I'm + + + align:start position:0% +the beginning of 28 uh ordinarily I'm +not in such a good hurry to dolge all my + + align:start position:0% +not in such a good hurry to dolge all my + + + align:start position:0% +not in such a good hurry to dolge all my +mistakes to people who me perform + + align:start position:0% +mistakes to people who me perform + + + align:start position:0% +mistakes to people who me perform +however I think in this case it's it's + + align:start position:0% +however I think in this case it's it's + + + align:start position:0% +however I think in this case it's it's +Germain um there was a wonderful comment + + align:start position:0% +Germain um there was a wonderful comment + + + align:start position:0% +Germain um there was a wonderful comment +that a colleague of yours whose name + + align:start position:0% +that a colleague of yours whose name + + + align:start position:0% +that a colleague of yours whose name +forgive me I can't remember the very + + align:start position:0% +forgive me I can't remember the very + + + align:start position:0% +forgive me I can't remember the very +first time I ever did this class with + + align:start position:0% +first time I ever did this class with + + + align:start position:0% +first time I ever did this class with +you um there were I think only three + + align:start position:0% +you um there were I think only three + + + align:start position:0% +you um there were I think only three +people or something it was anyway it was + + align:start position:0% +people or something it was anyway it was + + + align:start position:0% +people or something it was anyway it was +another composition uh professor and I + + align:start position:0% +another composition uh professor and I + + + align:start position:0% +another composition uh professor and I +was having trouble parsing out what + + align:start position:0% +was having trouble parsing out what + + + align:start position:0% +was having trouble parsing out what +looked on paper to be a very simple + + align:start position:0% +looked on paper to be a very simple + + + align:start position:0% +looked on paper to be a very simple +Melody but it was awkwardly written it + + align:start position:0% +Melody but it was awkwardly written it + + + align:start position:0% +Melody but it was awkwardly written it +was a uh they were funny intervals and + + align:start position:0% +was a uh they were funny intervals and + + + align:start position:0% +was a uh they were funny intervals and +and strange jumps on unusual syllables + + align:start position:0% +and strange jumps on unusual syllables + + + align:start position:0% +and strange jumps on unusual syllables +and the student composer it should be + + align:start position:0% +and the student composer it should be + + + align:start position:0% +and the student composer it should be +said was becoming annoyed with me for + + align:start position:0% +said was becoming annoyed with me for + + + align:start position:0% +said was becoming annoyed with me for +missing it repeatedly and then her + + align:start position:0% +missing it repeatedly and then her + + + align:start position:0% +missing it repeatedly and then her +professor raised his hand and very tly + + align:start position:0% +professor raised his hand and very tly + + + align:start position:0% +professor raised his hand and very tly +said + + align:start position:0% +said + + + align:start position:0% +said +well take an experienced musician in an + + align:start position:0% +well take an experienced musician in an + + + align:start position:0% +well take an experienced musician in an +awkward line of music and you can't + + align:start position:0% +awkward line of music and you can't + + + align:start position:0% +awkward line of music and you can't +expect it to be much smoother than that + + align:start position:0% +expect it to be much smoother than that + + + align:start position:0% +expect it to be much smoother than that +at first gloss and it was a very telling + + align:start position:0% +at first gloss and it was a very telling + + + align:start position:0% +at first gloss and it was a very telling +comment um and it's incredibly ephemeral + + align:start position:0% +comment um and it's incredibly ephemeral + + + align:start position:0% +comment um and it's incredibly ephemeral +Concept in in that you know what what + + align:start position:0% +Concept in in that you know what what + + + align:start position:0% +Concept in in that you know what what +does a smooth or logical or organic + + align:start position:0% +does a smooth or logical or organic + + + align:start position:0% +does a smooth or logical or organic +melody mean to each of us and it depends + + align:start position:0% +melody mean to each of us and it depends + + + align:start position:0% +melody mean to each of us and it depends +also on what compositional idiom you're + + align:start position:0% +also on what compositional idiom you're + + + align:start position:0% +also on what compositional idiom you're +working in you know something like this + + align:start position:0% +working in you know something like this + + + align:start position:0% +working in you know something like this +that owes so much to the tradition of uh + + align:start position:0% +that owes so much to the tradition of uh + + + align:start position:0% +that owes so much to the tradition of uh +say German art song or let's say uh + + align:start position:0% +say German art song or let's say uh + + + align:start position:0% +say German art song or let's say uh +basically art song from the mid mid 19th + + align:start position:0% +basically art song from the mid mid 19th + + + align:start position:0% +basically art song from the mid mid 19th +century um there are certain standards + + align:start position:0% +century um there are certain standards + + + align:start position:0% +century um there are certain standards +of of um excuse me standards isn't the + + align:start position:0% +of of um excuse me standards isn't the + + + align:start position:0% +of of um excuse me standards isn't the +word I want there are certain uh + + align:start position:0% +word I want there are certain uh + + + align:start position:0% +word I want there are certain uh +convention in the way Melodies will + + align:start position:0% +convention in the way Melodies will + + + align:start position:0% +convention in the way Melodies will +unfold that we all kind of accept and + + align:start position:0% +unfold that we all kind of accept and + + + align:start position:0% +unfold that we all kind of accept and +listen for and for some reason I I think + + align:start position:0% +listen for and for some reason I I think + + + align:start position:0% +listen for and for some reason I I think +it has largely to do with where you're + + align:start position:0% +it has largely to do with where you're + + + align:start position:0% +it has largely to do with where you're +going harmonically that interval is hard + + align:start position:0% +going harmonically that interval is hard + + + align:start position:0% +going harmonically that interval is hard +for me to hear the C to F it's only it's + + align:start position:0% +for me to hear the C to F it's only it's + + + align:start position:0% +for me to hear the C to F it's only it's +an open fifth it's the easiest interval + + align:start position:0% +an open fifth it's the easiest interval + + + align:start position:0% +an open fifth it's the easiest interval +you can possibly sing nonetheless + + align:start position:0% +you can possibly sing nonetheless + + + align:start position:0% +you can possibly sing nonetheless +because harmonically it's heading in a + + align:start position:0% +because harmonically it's heading in a + + + align:start position:0% +because harmonically it's heading in a +direction that doesn't necessarily make + + align:start position:0% +direction that doesn't necessarily make + + + align:start position:0% +direction that doesn't necessarily make +that much + + align:start position:0% +that much + + + align:start position:0% +that much +sense uh in regard to what has preceded + + align:start position:0% +sense uh in regard to what has preceded + + + align:start position:0% +sense uh in regard to what has preceded +it it feels a little bit awkward um now + + align:start position:0% +it it feels a little bit awkward um now + + + align:start position:0% +it it feels a little bit awkward um now +I understand where you're where you're + + align:start position:0% +I understand where you're where you're + + + align:start position:0% +I understand where you're where you're +wanting to wind up and that does make + + align:start position:0% +wanting to wind up and that does make + + + align:start position:0% +wanting to wind up and that does make +sense sort of on paper but at the same + + align:start position:0% +sense sort of on paper but at the same + + + align:start position:0% +sense sort of on paper but at the same +time you've embedded us so so deeply in + + align:start position:0% +time you've embedded us so so deeply in + + + align:start position:0% +time you've embedded us so so deeply in +this new harmonic + + align:start position:0% +this new harmonic + + + align:start position:0% +this new harmonic +area if you really want to get back to + + align:start position:0% +area if you really want to get back to + + + align:start position:0% +area if you really want to get back to +the home key it seems to me that the + + align:start position:0% +the home key it seems to me that the + + + align:start position:0% +the home key it seems to me that the +song should happen in three episodes one + + align:start position:0% +song should happen in three episodes one + + + align:start position:0% +song should happen in three episodes one +being the ultimate the uh initial + + align:start position:0% +being the ultimate the uh initial + + + align:start position:0% +being the ultimate the uh initial +statement rather in the home key area + + align:start position:0% +statement rather in the home key area + + + align:start position:0% +statement rather in the home key area +then your trip to whatever relative key + + align:start position:0% +then your trip to whatever relative key + + + align:start position:0% +then your trip to whatever relative key +area you wish to go and then some sort + + align:start position:0% +area you wish to go and then some sort + + + align:start position:0% +area you wish to go and then some sort +of vocal resolution that brings us back + + align:start position:0% +of vocal resolution that brings us back + + + align:start position:0% +of vocal resolution that brings us back +to the home area now again this the this + + align:start position:0% +to the home area now again this the this + + + align:start position:0% +to the home area now again this the this +is I'm talking strictly in terms of that + + align:start position:0% +is I'm talking strictly in terms of that + + + align:start position:0% +is I'm talking strictly in terms of that +kind of Convention of 19th century art + + align:start position:0% +kind of Convention of 19th century art + + + align:start position:0% +kind of Convention of 19th century art +song um this whole idea uh of symmetry + + align:start position:0% +song um this whole idea uh of symmetry + + + align:start position:0% +song um this whole idea uh of symmetry +which of course you know has been in + + align:start position:0% +which of course you know has been in + + + align:start position:0% +which of course you know has been in +existence long before that period but I + + align:start position:0% +existence long before that period but I + + + align:start position:0% +existence long before that period but I +think just for the sense + + align:start position:0% +think just for the sense + + + align:start position:0% +think just for the sense +of going back to the home key area you + + align:start position:0% +of going back to the home key area you + + + align:start position:0% +of going back to the home key area you +need to give the singer a little bit + + align:start position:0% +need to give the singer a little bit + + + align:start position:0% +need to give the singer a little bit +more and not just sort of let the piano + + align:start position:0% +more and not just sort of let the piano + + + align:start position:0% +more and not just sort of let the piano +take care of it there is of course I + + align:start position:0% +take care of it there is of course I + + + align:start position:0% +take care of it there is of course I +don't know how much Schuman you've + + align:start position:0% +don't know how much Schuman you've + + + align:start position:0% +don't know how much Schuman you've +listened to the art song of of Robert + + align:start position:0% +listened to the art song of of Robert + + + align:start position:0% +listened to the art song of of Robert +Schuman obviously right and left he does + + align:start position:0% +Schuman obviously right and left he does + + + align:start position:0% +Schuman obviously right and left he does +this very odd thing for those of you who + + align:start position:0% +this very odd thing for those of you who + + + align:start position:0% +this very odd thing for those of you who +have not listened to a lot of Schuman + + align:start position:0% +have not listened to a lot of Schuman + + + align:start position:0% +have not listened to a lot of Schuman +Shan is famous for writing these + + align:start position:0% +Shan is famous for writing these + + + align:start position:0% +Shan is famous for writing these +magnificent songs and then tacking on + + align:start position:0% +magnificent songs and then tacking on + + + align:start position:0% +magnificent songs and then tacking on +these seemingly like unrelated postludes + + align:start position:0% +these seemingly like unrelated postludes + + + align:start position:0% +these seemingly like unrelated postludes +that go on sometimes for a minute + + align:start position:0% +that go on sometimes for a minute + + + align:start position:0% +that go on sometimes for a minute +there's a famous song cycle of his where + + align:start position:0% +there's a famous song cycle of his where + + + align:start position:0% +there's a famous song cycle of his where +the last song the singer has just poured + + align:start position:0% +the last song the singer has just poured + + + align:start position:0% +the last song the singer has just poured +out her heart in this you know terribly + + align:start position:0% +out her heart in this you know terribly + + + align:start position:0% +out her heart in this you know terribly +wrenching way you know that her husband + + align:start position:0% +wrenching way you know that her husband + + + align:start position:0% +wrenching way you know that her husband +has died in her she will bury herself + + align:start position:0% +has died in her she will bury herself + + + align:start position:0% +has died in her she will bury herself +you know within her own heart and never + + align:start position:0% +you know within her own heart and never + + + align:start position:0% +you know within her own heart and never +never be revealed again very dark ending + + align:start position:0% +never be revealed again very dark ending + + + align:start position:0% +never be revealed again very dark ending +she finishes the song and then he sort + + align:start position:0% +she finishes the song and then he sort + + + align:start position:0% +she finishes the song and then he sort +of gives us a little leading chord and + + align:start position:0% +of gives us a little leading chord and + + + align:start position:0% +of gives us a little leading chord and +then goes off on this like gorgeous + + align:start position:0% +then goes off on this like gorgeous + + + align:start position:0% +then goes off on this like gorgeous +Little Piano Sonata all by himself and + + align:start position:0% +Little Piano Sonata all by himself and + + + align:start position:0% +Little Piano Sonata all by himself and +the singer just sort of stands there and + + align:start position:0% +the singer just sort of stands there and + + + align:start position:0% +the singer just sort of stands there and +the first time I saw that I was like oh + + align:start position:0% +the first time I saw that I was like oh + + + align:start position:0% +the first time I saw that I was like oh +thanks thanks a lot that's really handy + + align:start position:0% +thanks thanks a lot that's really handy + + + align:start position:0% +thanks thanks a lot that's really handy +so I think it can work in very specific + + align:start position:0% +so I think it can work in very specific + + + align:start position:0% +so I think it can work in very specific +context I mean I it's hard not to stand + + align:start position:0% +context I mean I it's hard not to stand + + + align:start position:0% +context I mean I it's hard not to stand +there and feel like you have egg on your + + align:start position:0% +there and feel like you have egg on your + + + align:start position:0% +there and feel like you have egg on your +face but unless you parse out the idea + + align:start position:0% +face but unless you parse out the idea + + + align:start position:0% +face but unless you parse out the idea +of of the the key that you want to end + + align:start position:0% +of of the the key that you want to end + + + align:start position:0% +of of the the key that you want to end +up in more thoroughly I say either + + align:start position:0% +up in more thoroughly I say either + + + align:start position:0% +up in more thoroughly I say either +elongate your + + align:start position:0% +elongate your + + + align:start position:0% +elongate your +postlude have it make more of a + + align:start position:0% +postlude have it make more of a + + + align:start position:0% +postlude have it make more of a +statement about what has preceded so it + + align:start position:0% +statement about what has preceded so it + + + align:start position:0% +statement about what has preceded so it +gives balance at the end of the song to + + align:start position:0% +gives balance at the end of the song to + + + align:start position:0% +gives balance at the end of the song to +what has happened at the front end + + align:start position:0% +what has happened at the front end + + + align:start position:0% +what has happened at the front end +because the front end is very strong you + + align:start position:0% +because the front end is very strong you + + + align:start position:0% +because the front end is very strong you +have this very emotional I mean it + + align:start position:0% +have this very emotional I mean it + + + align:start position:0% +have this very emotional I mean it +reminds me a little bit of um Al of of + + align:start position:0% +reminds me a little bit of um Al of of + + + align:start position:0% +reminds me a little bit of um Al of of +shat which I'm sure you've listen to uh + + align:start position:0% +shat which I'm sure you've listen to uh + + + align:start position:0% +shat which I'm sure you've listen to uh +where we have a distinct voice of a + + align:start position:0% +where we have a distinct voice of a + + + align:start position:0% +where we have a distinct voice of a +character and then a distinct voice of + + align:start position:0% +character and then a distinct voice of + + + align:start position:0% +character and then a distinct voice of +uh a narrator so you've given us this + + align:start position:0% +uh a narrator so you've given us this + + + align:start position:0% +uh a narrator so you've given us this +nice thing but then we're sort of + + align:start position:0% +nice thing but then we're sort of + + + align:start position:0% +nice thing but then we're sort of +missing the day new mall sort of missing + + align:start position:0% +missing the day new mall sort of missing + + + align:start position:0% +missing the day new mall sort of missing +the last step now obviously there's no + + align:start position:0% +the last step now obviously there's no + + + align:start position:0% +the last step now obviously there's no +more text in the poem you're all fresh + + align:start position:0% +more text in the poem you're all fresh + + + align:start position:0% +more text in the poem you're all fresh +out but I guess uh that's the one thing + + align:start position:0% +out but I guess uh that's the one thing + + + align:start position:0% +out but I guess uh that's the one thing +that is sort of missing to me an overall + + align:start position:0% +that is sort of missing to me an overall + + + align:start position:0% +that is sort of missing to me an overall +sense of balance uh to the song in terms + + align:start position:0% +sense of balance uh to the song in terms + + + align:start position:0% +sense of balance uh to the song in terms +of how it sings in terms of how it feels + + align:start position:0% +of how it sings in terms of how it feels + + + align:start position:0% +of how it sings in terms of how it feels +in the voice it's very nicely written in + + align:start position:0% +in the voice it's very nicely written in + + + align:start position:0% +in the voice it's very nicely written in +terms of uh vocal line um a typical trap + + align:start position:0% +terms of uh vocal line um a typical trap + + + align:start position:0% +terms of uh vocal line um a typical trap +that young composers often fall into + + align:start position:0% +that young composers often fall into + + + align:start position:0% +that young composers often fall into +including ones who really should know + + align:start position:0% +including ones who really should know + + + align:start position:0% +including ones who really should know +better because they're earning their + + align:start position:0% +better because they're earning their + + + align:start position:0% +better because they're earning their +money being composers um is to either be + + align:start position:0% +money being composers um is to either be + + + align:start position:0% +money being composers um is to either be +far too conservative with the voice and + + align:start position:0% +far too conservative with the voice and + + + align:start position:0% +far too conservative with the voice and +just sort of out of out of fear of of + + align:start position:0% +just sort of out of out of fear of of + + + align:start position:0% +just sort of out of out of fear of of +demanding too much or just going + + align:start position:0% +demanding too much or just going + + + align:start position:0% +demanding too much or just going +completely off the deep end and having + + align:start position:0% +completely off the deep end and having + + + align:start position:0% +completely off the deep end and having +you know making demands of this of the + + align:start position:0% +you know making demands of this of the + + + align:start position:0% +you know making demands of this of the +singer that are just not vocally + + align:start position:0% +singer that are just not vocally + + + align:start position:0% +singer that are just not vocally +appropriate for the person's uh fa or + + align:start position:0% +appropriate for the person's uh fa or + + + align:start position:0% +appropriate for the person's uh fa or +voice cat organization uh and you've + + align:start position:0% +voice cat organization uh and you've + + + align:start position:0% +voice cat organization uh and you've +done a good job of sort of having one + + align:start position:0% +done a good job of sort of having one + + + align:start position:0% +done a good job of sort of having one +foot in each Camp having the bulk of the + + align:start position:0% +foot in each Camp having the bulk of the + + + align:start position:0% +foot in each Camp having the bulk of the +melody sitting in a very comfortable + + align:start position:0% +melody sitting in a very comfortable + + + align:start position:0% +melody sitting in a very comfortable +sort of middle range and allowing it to + + align:start position:0% +sort of middle range and allowing it to + + + align:start position:0% +sort of middle range and allowing it to +Arc up and down + + align:start position:0% +Arc up and down + + + align:start position:0% +Arc up and down +um to make certain dramatic statements + + align:start position:0% +um to make certain dramatic statements + + + align:start position:0% +um to make certain dramatic statements +which I think is really clever um and + + align:start position:0% +which I think is really clever um and + + + align:start position:0% +which I think is really clever um and +difficult to do as well so cros to you + + align:start position:0% +difficult to do as well so cros to you + + + align:start position:0% +difficult to do as well so cros to you +for + + align:start position:0% +for + + + align:start position:0% +for +that um Daniel you forgive me if i n on + + align:start position:0% +that um Daniel you forgive me if i n on + + + align:start position:0% +that um Daniel you forgive me if i n on +for a couple seconds longer um with + + align:start position:0% +for a couple seconds longer um with + + + align:start position:0% +for a couple seconds longer um with +regard to the score itself there's one + + align:start position:0% +regard to the score itself there's one + + + align:start position:0% +regard to the score itself there's one +particularly strange thing and Peter you + + align:start position:0% +particularly strange thing and Peter you + + + align:start position:0% +particularly strange thing and Peter you +need to put in your two cents here but + + align:start position:0% +need to put in your two cents here but + + + align:start position:0% +need to put in your two cents here but +it's measure 20 it's a very awkward way + + align:start position:0% +it's measure 20 it's a very awkward way + + + align:start position:0% +it's measure 20 it's a very awkward way +of notating that Rhythm if that's indeed + + align:start position:0% +of notating that Rhythm if that's indeed + + + align:start position:0% +of notating that Rhythm if that's indeed +the Rhythm that you + + align:start position:0% +the Rhythm that you + + + align:start position:0% +the Rhythm that you +intended it comes out is the night was + + align:start position:0% +intended it comes out is the night was + + + align:start position:0% +intended it comes out is the night was +dark no father was there it was kind of + + align:start position:0% +dark no father was there it was kind of + + + align:start position:0% +dark no father was there it was kind of +a if I were + + align:start position:0% +a if I were + + + align:start position:0% +a if I were +to recite it with a rhythm that made the + + align:start position:0% +to recite it with a rhythm that made the + + + align:start position:0% +to recite it with a rhythm that made the +most sense to me with in context of the + + align:start position:0% +most sense to me with in context of the + + + align:start position:0% +most sense to me with in context of the +speech I would have probably said the + + align:start position:0% +speech I would have probably said the + + + align:start position:0% +speech I would have probably said the +night was dark no father was there in + + align:start position:0% +night was dark no father was there in + + + align:start position:0% +night was dark no father was there in +other words back the whole thing up by + + align:start position:0% +other words back the whole thing up by + + + align:start position:0% +other words back the whole thing up by +an E + + align:start position:0% +an E + + + align:start position:0% +an E +note the way it's written there in uh in + + align:start position:0% +note the way it's written there in uh in + + + align:start position:0% +note the way it's written there in uh in +68 we're looking for certain visual + + align:start position:0% +68 we're looking for certain visual + + + align:start position:0% +68 we're looking for certain visual +groupings on the page and to give us you + + align:start position:0% +groupings on the page and to give us you + + + align:start position:0% +groupings on the page and to give us you +know the qu note makes sense I mean it's + + align:start position:0% +know the qu note makes sense I mean it's + + + align:start position:0% +know the qu note makes sense I mean it's +nothing fancy but what trips up the eye + + align:start position:0% +nothing fancy but what trips up the eye + + + align:start position:0% +nothing fancy but what trips up the eye +is the dotted e tied to the 16th tied to + + align:start position:0% +is the dotted e tied to the 16th tied to + + + align:start position:0% +is the dotted e tied to the 16th tied to +the two additional eights if you see + + align:start position:0% +the two additional eights if you see + + + align:start position:0% +the two additional eights if you see +what I mean that's a that looks odd on + + align:start position:0% +what I mean that's a that looks odd on + + + align:start position:0% +what I mean that's a that looks odd on +the page and it makes if we're thinking + + align:start position:0% +the page and it makes if we're thinking + + + align:start position:0% +the page and it makes if we're thinking +in 68 we're not necessarily going to + + align:start position:0% +in 68 we're not necessarily going to + + + align:start position:0% +in 68 we're not necessarily going to +parse that out as a sudden feel of 34 + + align:start position:0% +parse that out as a sudden feel of 34 + + + align:start position:0% +parse that out as a sudden feel of 34 +because that's not a 34 pulse is not + + align:start position:0% +because that's not a 34 pulse is not + + + align:start position:0% +because that's not a 34 pulse is not +something that we're feeling uniformly + + align:start position:0% +something that we're feeling uniformly + + + align:start position:0% +something that we're feeling uniformly +throughout this section you see what I'm + + align:start position:0% +throughout this section you see what I'm + + + align:start position:0% +throughout this section you see what I'm +talking about I'm not sure I'm + + align:start position:0% +talking about I'm not sure I'm + + + align:start position:0% +talking about I'm not sure I'm +articulating it as clearly as as a + + align:start position:0% +articulating it as clearly as as a + + + align:start position:0% +articulating it as clearly as as a +composer would but um I say either if + + align:start position:0% +composer would but um I say either if + + + align:start position:0% +composer would but um I say either if +you want to stick to that Rhythm then + + align:start position:0% +you want to stick to that Rhythm then + + + align:start position:0% +you want to stick to that Rhythm then +see if you can find a different way of + + align:start position:0% +see if you can find a different way of + + + align:start position:0% +see if you can find a different way of +notating it with Tide notes tide notes + + align:start position:0% +notating it with Tide notes tide notes + + + align:start position:0% +notating it with Tide notes tide notes +seem fussy and weird but actually + + align:start position:0% +seem fussy and weird but actually + + + align:start position:0% +seem fussy and weird but actually +visually they can make the language much + + align:start position:0% +visually they can make the language much + + + align:start position:0% +visually they can make the language much +clearer to the eye when looking at + + align:start position:0% +clearer to the eye when looking at + + + align:start position:0% +clearer to the eye when looking at +it my only suggestion uh in my + + align:start position:0% +it my only suggestion uh in my + + + align:start position:0% +it my only suggestion uh in my +own uh what am I trying to + + align:start position:0% +own uh what am I trying to + + + align:start position:0% +own uh what am I trying to +say in support of my other suggestion + + align:start position:0% +say in support of my other suggestion + + + align:start position:0% +say in support of my other suggestion +which is shifting up slightly like + + align:start position:0% +which is shifting up slightly like + + + align:start position:0% +which is shifting up slightly like +moving it back by an eighth note would + + align:start position:0% +moving it back by an eighth note would + + + align:start position:0% +moving it back by an eighth note would +be to give a truer sense of the shape of + + align:start position:0% +be to give a truer sense of the shape of + + + align:start position:0% +be to give a truer sense of the shape of +the text this comes out feel like no + + align:start position:0% +the text this comes out feel like no + + + align:start position:0% +the text this comes out feel like no +father was there I'm not sure if you + + align:start position:0% +father was there I'm not sure if you + + + align:start position:0% +father was there I'm not sure if you +mean no father was there or no father + + align:start position:0% +mean no father was there or no father + + + align:start position:0% +mean no father was there or no father +was there you need to make up your mind + + align:start position:0% +was there you need to make up your mind + + + align:start position:0% +was there you need to make up your mind +which is the important word in there + + align:start position:0% +which is the important word in there + + + align:start position:0% +which is the important word in there +because the way you said it it's it's it + + align:start position:0% +because the way you said it it's it's it + + + align:start position:0% +because the way you said it it's it's it +falls in neither Camp you + + align:start position:0% + + + + align:start position:0% + +see I'm trying to think if I had any + + align:start position:0% +see I'm trying to think if I had any + + + align:start position:0% +see I'm trying to think if I had any +other ideas with regard to the score I + + align:start position:0% +other ideas with regard to the score I + + + align:start position:0% +other ideas with regard to the score I +didn't Daniel would you please feel + + align:start position:0% +didn't Daniel would you please feel + + + align:start position:0% +didn't Daniel would you please feel +through that I'll say a couple of things + + align:start position:0% +through that I'll say a couple of things + + + align:start position:0% +through that I'll say a couple of things +um first that I appreciate a lot of the + + align:start position:0% +um first that I appreciate a lot of the + + + align:start position:0% +um first that I appreciate a lot of the +articulation that you've given this + + align:start position:0% +articulation that you've given this + + + align:start position:0% +articulation that you've given this +piano part um and but one one difficult + + align:start position:0% +piano part um and but one one difficult + + + align:start position:0% +piano part um and but one one difficult +thing about this piece is when there are + + align:start position:0% +thing about this piece is when there are + + + align:start position:0% +thing about this piece is when there are +different articulations in each hand and + + align:start position:0% +different articulations in each hand and + + + align:start position:0% +different articulations in each hand and +it's + + align:start position:0% +it's + + + align:start position:0% +it's +something that certainly as a Pianist + + align:start position:0% +something that certainly as a Pianist + + + align:start position:0% +something that certainly as a Pianist +you come across but but it's always a + + align:start position:0% +you come across but but it's always a + + + align:start position:0% +you come across but but it's always a +very uh specific thing that a composer + + align:start position:0% +very uh specific thing that a composer + + + align:start position:0% +very uh specific thing that a composer +is going for when when a Pianist is + + align:start position:0% +is going for when when a Pianist is + + + align:start position:0% +is going for when when a Pianist is +asked to do such separate articulations + + align:start position:0% +asked to do such separate articulations + + + align:start position:0% +asked to do such separate articulations +in the hands um and even I don't know if + + align:start position:0% +in the hands um and even I don't know if + + + align:start position:0% +in the hands um and even I don't know if +you noticed in 24 I think the second + + align:start position:0% +you noticed in 24 I think the second + + + align:start position:0% +you noticed in 24 I think the second +time we did it I played the right hand + + align:start position:0% +time we did it I played the right hand + + + align:start position:0% +time we did it I played the right hand +Legato and I played the left hand + + align:start position:0% +Legato and I played the left hand + + + align:start position:0% +Legato and I played the left hand +staccato I you know I revers the + + align:start position:0% +staccato I you know I revers the + + + align:start position:0% +staccato I you know I revers the +articulations um and I guess I'm only + + align:start position:0% +articulations um and I guess I'm only + + + align:start position:0% +articulations um and I guess I'm only +mentioning this to + + align:start position:0% +mentioning this to + + + align:start position:0% +mentioning this to +say be be careful when you do that um + + align:start position:0% +say be be careful when you do that um + + + align:start position:0% +say be be careful when you do that um +because it it makes such a strong + + align:start position:0% +because it it makes such a strong + + + align:start position:0% +because it it makes such a strong +impression on me to see that on the page + + align:start position:0% +impression on me to see that on the page + + + align:start position:0% +impression on me to see that on the page +um but I agree that the + + align:start position:0% +um but I agree that the + + + align:start position:0% +um but I agree that the +end feels it feels a little lopsided in + + align:start position:0% +end feels it feels a little lopsided in + + + align:start position:0% +end feels it feels a little lopsided in +favor of of the front of the piece and + + align:start position:0% +favor of of the front of the piece and + + + align:start position:0% +favor of of the front of the piece and +that if if you do get a chance to expand + + align:start position:0% +that if if you do get a chance to expand + + + align:start position:0% +that if if you do get a chance to expand +on the end I was I love measure eight + + align:start position:0% +on the end I was I love measure eight + + + align:start position:0% +on the end I was I love measure eight +when that Chola Rhythm comes in uh in my + + align:start position:0% +when that Chola Rhythm comes in uh in my + + + align:start position:0% +when that Chola Rhythm comes in uh in my +part this + + align:start position:0% +part this + + + align:start position:0% +part this +[Music] + + align:start position:0% + + + + align:start position:0% + +and I was kind of waiting for that to + + align:start position:0% +and I was kind of waiting for that to + + + align:start position:0% +and I was kind of waiting for that to +come back at the end um and I know you + + align:start position:0% +come back at the end um and I know you + + + align:start position:0% +come back at the end um and I know you +don't have the same text to work with + + align:start position:0% +don't have the same text to work with + + + align:start position:0% +don't have the same text to work with +but it's such a memorable moment that if + + align:start position:0% +but it's such a memorable moment that if + + + align:start position:0% +but it's such a memorable moment that if +that kind of gesture were to come back + + align:start position:0% +that kind of gesture were to come back + + + align:start position:0% +that kind of gesture were to come back +at the end it would give us that sense + + align:start position:0% +at the end it would give us that sense + + + align:start position:0% +at the end it would give us that sense +of return and solidifying you know the + + align:start position:0% +of return and solidifying you know the + + + align:start position:0% +of return and solidifying you know the +home key and all of + + align:start position:0% +home key and all of + + + align:start position:0% +home key and all of +that no very very nice part to play I + + align:start position:0% +that no very very nice part to play I + + + align:start position:0% +that no very very nice part to play I +wanted to extract + + align:start position:0% +wanted to extract + + + align:start position:0% +wanted to extract +briefly on the points Danel made about + + align:start position:0% +briefly on the points Danel made about + + + align:start position:0% +briefly on the points Danel made about +articulation which are really really + + align:start position:0% +articulation which are really really + + + align:start position:0% +articulation which are really really +really well put one thing that I find I + + align:start position:0% +really well put one thing that I find I + + + align:start position:0% +really well put one thing that I find I +have found I should say uh frequently is + + align:start position:0% +have found I should say uh frequently is + + + align:start position:0% +have found I should say uh frequently is +often what makes differences in + + align:start position:0% +often what makes differences in + + + align:start position:0% +often what makes differences in +articulation really work or what + + align:start position:0% +articulation really work or what + + + align:start position:0% +articulation really work or what +gives tension to a piece is if the + + align:start position:0% +gives tension to a piece is if the + + + align:start position:0% +gives tension to a piece is if the +entire piano part has one texture and + + align:start position:0% +entire piano part has one texture and + + + align:start position:0% +entire piano part has one texture and +the voice is asked to use a different + + align:start position:0% +the voice is asked to use a different + + + align:start position:0% +the voice is asked to use a different +texture um I can think of aund different + + align:start position:0% +texture um I can think of aund different + + + align:start position:0% +texture um I can think of aund different +examples um of course now I can't oh + + align:start position:0% +examples um of course now I can't oh + + + align:start position:0% +examples um of course now I can't oh +there there's a a piece probably one of + + align:start position:0% +there there's a a piece probably one of + + + align:start position:0% +there there's a a piece probably one of +many called of + + align:start position:0% + + + + align:start position:0% + +shat where the piano is really imitating + + align:start position:0% +shat where the piano is really imitating + + + align:start position:0% +shat where the piano is really imitating +the plucking of a mandolin it's + + align:start position:0% + + + + align:start position:0% + +like and the voice has this sort of + + align:start position:0% +like and the voice has this sort of + + + align:start position:0% +like and the voice has this sort of +fabulous sort of honeyed soaring + + align:start position:0% +fabulous sort of honeyed soaring + + + align:start position:0% +fabulous sort of honeyed soaring +gorgeous thing but it's the contrast + + align:start position:0% +gorgeous thing but it's the contrast + + + align:start position:0% +gorgeous thing but it's the contrast +between you know if the piano was + + align:start position:0% +between you know if the piano was + + + align:start position:0% +between you know if the piano was +all and the voice was doing that it + + align:start position:0% +all and the voice was doing that it + + + align:start position:0% +all and the voice was doing that it +would sound like a big muddy mess but + + align:start position:0% +would sound like a big muddy mess but + + + align:start position:0% +would sound like a big muddy mess but +because it's + + align:start position:0% +because it's + + + align:start position:0% +because it's +juxtaposed dry against wet pretty good + + align:start position:0% +juxtaposed dry against wet pretty good + + + align:start position:0% +juxtaposed dry against wet pretty good +way of putting it um somehow it just + + align:start position:0% +way of putting it um somehow it just + + + align:start position:0% +way of putting it um somehow it just +makes the song Come to Life it makes it + + align:start position:0% +makes the song Come to Life it makes it + + + align:start position:0% +makes the song Come to Life it makes it +so romantic and so evocative suddenly + + align:start position:0% +so romantic and so evocative suddenly + + + align:start position:0% +so romantic and so evocative suddenly +you hear precisely what is intended + + align:start position:0% +you hear precisely what is intended + + + align:start position:0% +you hear precisely what is intended +you've got such a good a sense of the + + align:start position:0% +you've got such a good a sense of the + + + align:start position:0% +you've got such a good a sense of the +sort of like + + align:start position:0% +sort of like + + + align:start position:0% +sort of like +brooding uh picture that the poem uh + + align:start position:0% +brooding uh picture that the poem uh + + + align:start position:0% +brooding uh picture that the poem uh +delineates I think that you can work + + align:start position:0% +delineates I think that you can work + + + align:start position:0% +delineates I think that you can work +using articulation specifically between + + align:start position:0% +using articulation specifically between + + + align:start position:0% +using articulation specifically between +the voice partner piano part um or + + align:start position:0% +the voice partner piano part um or + + + align:start position:0% +the voice partner piano part um or +Dynamics or whatever it may be to + + align:start position:0% +Dynamics or whatever it may be to + + + align:start position:0% +Dynamics or whatever it may be to +heighten that and make it more specific + + align:start position:0% +heighten that and make it more specific + + + align:start position:0% +heighten that and make it more specific +I also thought of one other thing that I + + align:start position:0% +I also thought of one other thing that I + + + align:start position:0% +I also thought of one other thing that I +wanted to mention which + + align:start position:0% +wanted to mention which + + + align:start position:0% +wanted to mention which +is uh and again this has a lot to do + + align:start position:0% +is uh and again this has a lot to do + + + align:start position:0% +is uh and again this has a lot to do +with the convention of 19th century song + + align:start position:0% +with the convention of 19th century song + + + align:start position:0% +with the convention of 19th century song +which this which your composition seems + + align:start position:0% +which this which your composition seems + + + align:start position:0% +which this which your composition seems +to owe uh a good deal to and that is a a + + align:start position:0% +to owe uh a good deal to and that is a a + + + align:start position:0% +to owe uh a good deal to and that is a a +not a terribly strong feeling of cadence + + align:start position:0% +not a terribly strong feeling of cadence + + + align:start position:0% +not a terribly strong feeling of cadence +at the end and I'm not saying that it + + align:start position:0% +at the end and I'm not saying that it + + + align:start position:0% +at the end and I'm not saying that it +has to be that way of course it doesn't + + align:start position:0% +has to be that way of course it doesn't + + + align:start position:0% +has to be that way of course it doesn't +it's always one's individual choice but + + align:start position:0% +it's always one's individual choice but + + + align:start position:0% +it's always one's individual choice but +if you're working within this harmonic + + align:start position:0% +if you're working within this harmonic + + + align:start position:0% +if you're working within this harmonic +language uh unless you're going to do + + align:start position:0% +language uh unless you're going to do + + + align:start position:0% +language uh unless you're going to do +something that + + align:start position:0% +something that + + + align:start position:0% +something that +is very specifically moving away from + + align:start position:0% +is very specifically moving away from + + + align:start position:0% +is very specifically moving away from +that tradition in other words paying uh + + align:start position:0% +that tradition in other words paying uh + + + align:start position:0% +that tradition in other words paying uh +tribute to that tradition of of vocal + + align:start position:0% +tribute to that tradition of of vocal + + + align:start position:0% +tribute to that tradition of of vocal +and piano writing yet putting your own + + align:start position:0% +and piano writing yet putting your own + + + align:start position:0% +and piano writing yet putting your own +impr prematur on it I think it needs to + + align:start position:0% +impr prematur on it I think it needs to + + + align:start position:0% +impr prematur on it I think it needs to +be more specific and clearly articulated + + align:start position:0% +be more specific and clearly articulated + + + align:start position:0% +be more specific and clearly articulated +then sort of a a Cadence that kind of + + align:start position:0% +then sort of a a Cadence that kind of + + + align:start position:0% +then sort of a a Cadence that kind of +hints at something a little bit more + + align:start position:0% +hints at something a little bit more + + + align:start position:0% +hints at something a little bit more +abstract but doesn't really deliver bit + + align:start position:0% +abstract but doesn't really deliver bit + + + align:start position:0% +abstract but doesn't really deliver bit +of goods so again it all gets back to + + align:start position:0% +of goods so again it all gets back to + + + align:start position:0% +of goods so again it all gets back to +the idea of giving the piece more + + align:start position:0% +the idea of giving the piece more + + + align:start position:0% +the idea of giving the piece more +balance giving it a little something on + + align:start position:0% +balance giving it a little something on + + + align:start position:0% +balance giving it a little something on +the end to weigh it down if that makes + + align:start position:0% +the end to weigh it down if that makes + + + align:start position:0% +the end to weigh it down if that makes +sense um for the piano part purposely + + align:start position:0% +sense um for the piano part purposely + + + align:start position:0% +sense um for the piano part purposely +didn't want to have strong Cadence + + align:start position:0% +didn't want to have strong Cadence + + + align:start position:0% +didn't want to have strong Cadence +because I wanted to go back to text + + align:start position:0% +because I wanted to go back to text + + + align:start position:0% +because I wanted to go back to text +painting for the vapor flu um + + align:start position:0% +painting for the vapor flu um + + + align:start position:0% +painting for the vapor flu um +part but yeah I agree I should expand + + align:start position:0% +part but yeah I agree I should expand + + + align:start position:0% +part but yeah I agree I should expand +more upon if that's the intent then + + align:start position:0% +more upon if that's the intent then + + + align:start position:0% +more upon if that's the intent then +there's a good deal more you can do to + + align:start position:0% +there's a good deal more you can do to + + + align:start position:0% +there's a good deal more you can do to +help push your pianist in that Direction + + align:start position:0% +help push your pianist in that Direction + + + align:start position:0% +help push your pianist in that Direction +and again you could feel free to + + align:start position:0% +and again you could feel free to + + + align:start position:0% +and again you could feel free to +interrup me but I would suggest marking + + align:start position:0% +interrup me but I would suggest marking + + + align:start position:0% +interrup me but I would suggest marking +your ritardando earlier and marking + + align:start position:0% +your ritardando earlier and marking + + + align:start position:0% +your ritardando earlier and marking +Dynamics for sure uh with actual words + + align:start position:0% +Dynamics for sure uh with actual words + + + align:start position:0% +Dynamics for sure uh with actual words +or like uh morendo or + + align:start position:0% +or like uh morendo or + + + align:start position:0% +or like uh morendo or +uh I don't know just find find find the + + align:start position:0% +uh I don't know just find find find the + + + align:start position:0% +uh I don't know just find find find the +right combination of of words and + + align:start position:0% +right combination of of words and + + + align:start position:0% +right combination of of words and +diacritical markings to indicate that + + align:start position:0% +diacritical markings to indicate that + + + align:start position:0% +diacritical markings to indicate that +you're looking for a very specific sort + + align:start position:0% +you're looking for a very specific sort + + + align:start position:0% +you're looking for a very specific sort +of ephemeral Vanishing vaporous effect + + align:start position:0% +of ephemeral Vanishing vaporous effect + + + align:start position:0% +of ephemeral Vanishing vaporous effect +because here looking at it it looks like + + align:start position:0% +because here looking at it it looks like + + + align:start position:0% +because here looking at it it looks like +you want the same in all four measures + + align:start position:0% +you want the same in all four measures + + + align:start position:0% +you want the same in all four measures +and a little bit of slowing down and a + + align:start position:0% +and a little bit of slowing down and a + + + align:start position:0% +and a little bit of slowing down and a +little bit quiet in the last measure + + align:start position:0% +little bit quiet in the last measure + + + align:start position:0% +little bit quiet in the last measure +when in fact the effect you're going for + + align:start position:0% +when in fact the effect you're going for + + + align:start position:0% +when in fact the effect you're going for +will demand a lot + + align:start position:0% +will demand a lot + + + align:start position:0% +will demand a lot +more uh a lot more of something of De + + align:start position:0% +more uh a lot more of something of De + + + align:start position:0% +more uh a lot more of something of De +Crescendo or lightness of touch or more + + align:start position:0% +Crescendo or lightness of touch or more + + + align:start position:0% +Crescendo or lightness of touch or more +pedal or less pedal or something but + + align:start position:0% +pedal or less pedal or something but + + + align:start position:0% +pedal or less pedal or something but +whatever it is don't be afraid to be + + align:start position:0% +whatever it is don't be afraid to be + + + align:start position:0% +whatever it is don't be afraid to be +specific Daniel made a great comment at + + align:start position:0% +specific Daniel made a great comment at + + + align:start position:0% +specific Daniel made a great comment at +the beginning which is that a + + align:start position:0% +the beginning which is that a + + + align:start position:0% +the beginning which is that a +well-marked piece I mean it may seem + + align:start position:0% +well-marked piece I mean it may seem + + + align:start position:0% +well-marked piece I mean it may seem +fiddly and fussy to go in you know + + align:start position:0% +fiddly and fussy to go in you know + + + align:start position:0% +fiddly and fussy to go in you know +finale or whatever put in all those + + align:start position:0% +finale or whatever put in all those + + + align:start position:0% +finale or whatever put in all those +stupid Within These pedal articulations + + align:start position:0% +stupid Within These pedal articulations + + + align:start position:0% +stupid Within These pedal articulations +we love that kind of thing that's that's + + align:start position:0% +we love that kind of thing that's that's + + + align:start position:0% +we love that kind of thing that's that's +where we we sort of live and die as + + align:start position:0% +where we we sort of live and die as + + + align:start position:0% +where we we sort of live and die as +performers I mean I love having you know + + align:start position:0% +performers I mean I love having you know + + + align:start position:0% +performers I mean I love having you know +a piece by I know name name your + + align:start position:0% +a piece by I know name name your + + + align:start position:0% +a piece by I know name name your +favorite 17th Century composer you know + + align:start position:0% +favorite 17th Century composer you know + + + align:start position:0% +favorite 17th Century composer you know +where there are no diacritical markings + + align:start position:0% +where there are no diacritical markings + + + align:start position:0% +where there are no diacritical markings +at all because you know you get to make + + align:start position:0% +at all because you know you get to make + + + align:start position:0% +at all because you know you get to make +up your own mind about things but what I + + align:start position:0% +up your own mind about things but what I + + + align:start position:0% +up your own mind about things but what I +particularly love is a composer like + + align:start position:0% +particularly love is a composer like + + + align:start position:0% +particularly love is a composer like +Benjamin Brittain where everything was + + align:start position:0% +Benjamin Brittain where everything was + + + align:start position:0% +Benjamin Brittain where everything was +incredibly specific and he was Notorious + + align:start position:0% +incredibly specific and he was Notorious + + + align:start position:0% +incredibly specific and he was Notorious +for being so dactic and really + + align:start position:0% +for being so dactic and really + + + align:start position:0% +for being so dactic and really +irritating with his publisher be like he + + align:start position:0% +irritating with his publisher be like he + + + align:start position:0% +irritating with his publisher be like he +you left the rest out throw them away + + align:start position:0% +you left the rest out throw them away + + + align:start position:0% +you left the rest out throw them away +print it again so the more specific you + + align:start position:0% +print it again so the more specific you + + + align:start position:0% +print it again so the more specific you +can be the stronger impression you give + + align:start position:0% +can be the stronger impression you give + + + align:start position:0% +can be the stronger impression you give +us of what you intend so in other words + + align:start position:0% +us of what you intend so in other words + + + align:start position:0% +us of what you intend so in other words +if there aren't enough di critical + + align:start position:0% +if there aren't enough di critical + + + align:start position:0% +if there aren't enough di critical +markings it seems to us like you have it + + align:start position:0% +markings it seems to us like you have it + + + align:start position:0% +markings it seems to us like you have it +made up your mind and yet you're telling + + align:start position:0% +made up your mind and yet you're telling + + + align:start position:0% +made up your mind and yet you're telling +me that you have a very specific thing + + align:start position:0% +me that you have a very specific thing + + + align:start position:0% +me that you have a very specific thing +in mind so let that be expressed on the + + align:start position:0% +in mind so let that be expressed on the + + + align:start position:0% +in mind so let that be expressed on the +page Peter what would you like to do + + align:start position:0% +page Peter what would you like to do + + + align:start position:0% +page Peter what would you like to do +shall we move on yeah all right good + + align:start position:0% +shall we move on yeah all right good + + + align:start position:0% +shall we move on yeah all right good +that's very beautiful Stephanie nice job + + align:start position:0% +that's very beautiful Stephanie nice job + + + align:start position:0% +that's very beautiful Stephanie nice job +Round of Applause for the + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +composer \ No newline at end of file diff --git a/4lUVayy53V4.txt b/4lUVayy53V4.txt new file mode 100644 index 0000000000000000000000000000000000000000..09d51489d2a8dd05803fdf779fbdf323f5d58996 --- /dev/null +++ b/4lUVayy53V4.txt @@ -0,0 +1,1843 @@ +align:start position:0% + +welcome back to 8701 + + align:start position:0% +welcome back to 8701 + + + align:start position:0% +welcome back to 8701 +so in this lecture we have a very brief + + align:start position:0% +so in this lecture we have a very brief + + + align:start position:0% +so in this lecture we have a very brief +view at the current status of higgs + + align:start position:0% +view at the current status of higgs + + + align:start position:0% +view at the current status of higgs +boson research + + align:start position:0% +boson research + + + align:start position:0% +boson research +and i have to tell you that we could + + align:start position:0% +and i have to tell you that we could + + + align:start position:0% +and i have to tell you that we could +spend an entire week + + align:start position:0% +spend an entire week + + + align:start position:0% +spend an entire week +discussing this i just give you the high + + align:start position:0% +discussing this i just give you the high + + + align:start position:0% +discussing this i just give you the high +level overview maybe the you know 30 000 + + align:start position:0% +level overview maybe the you know 30 000 + + + align:start position:0% +level overview maybe the you know 30 000 +feet kind of overview of what we know + + align:start position:0% +feet kind of overview of what we know + + + align:start position:0% +feet kind of overview of what we know +about the exposure + + align:start position:0% +about the exposure + + + align:start position:0% +about the exposure +on the canvas page you'll find a + + align:start position:0% +on the canvas page you'll find a + + + align:start position:0% +on the canvas page you'll find a +reference to a summary report which + + align:start position:0% +reference to a summary report which + + + align:start position:0% +reference to a summary report which +gives you a little bit more information + + align:start position:0% +gives you a little bit more information + + + align:start position:0% +gives you a little bit more information +than i give you here + + align:start position:0% +than i give you here + + + align:start position:0% +than i give you here +but i do think that there's a few things + + align:start position:0% +but i do think that there's a few things + + + align:start position:0% +but i do think that there's a few things +to highlight and those are the ones + + align:start position:0% +to highlight and those are the ones + + + align:start position:0% +to highlight and those are the ones +which i'm going to talk about + + align:start position:0% +which i'm going to talk about + + + align:start position:0% +which i'm going to talk about +the first part is that we have + + align:start position:0% +the first part is that we have + + + align:start position:0% +the first part is that we have +discovered the higgs boson in the case + + align:start position:0% +discovered the higgs boson in the case + + + align:start position:0% +discovered the higgs boson in the case +to photons and also indicates to z + + align:start position:0% +to photons and also indicates to z + + + align:start position:0% +to photons and also indicates to z +bosons where the zebras and itself + + align:start position:0% +bosons where the zebras and itself + + + align:start position:0% +bosons where the zebras and itself +decays into a pair of + + align:start position:0% +decays into a pair of + + + align:start position:0% +decays into a pair of +leptons electrons and neurons and the + + align:start position:0% +leptons electrons and neurons and the + + + align:start position:0% +leptons electrons and neurons and the +detectors we have available + + align:start position:0% +detectors we have available + + + align:start position:0% +detectors we have available +and here this is an example for atlas + + align:start position:0% +and here this is an example for atlas + + + align:start position:0% +and here this is an example for atlas +and for cms + + align:start position:0% +and for cms + + + align:start position:0% +and for cms +they are very good in measuring with + + align:start position:0% +they are very good in measuring with + + + align:start position:0% +they are very good in measuring with +precision the + + align:start position:0% +precision the + + + align:start position:0% +precision the +the energy or momentum of photons + + align:start position:0% +the energy or momentum of photons + + + align:start position:0% +the energy or momentum of photons +electrons and neurons so this allows us + + align:start position:0% +electrons and neurons so this allows us + + + align:start position:0% +electrons and neurons so this allows us +to then reconstruct + + align:start position:0% +to then reconstruct + + + align:start position:0% +to then reconstruct +the mass of the higgs boson as it goes + + align:start position:0% +the mass of the higgs boson as it goes + + + align:start position:0% +the mass of the higgs boson as it goes +through the decay + + align:start position:0% +through the decay + + + align:start position:0% +through the decay +and you can see this here this is 125 gb + + align:start position:0% +and you can see this here this is 125 gb + + + align:start position:0% +and you can see this here this is 125 gb +we construct the two photon final state + + align:start position:0% +we construct the two photon final state + + + align:start position:0% +we construct the two photon final state +so we have fixed to + + align:start position:0% +so we have fixed to + + + align:start position:0% +so we have fixed to +two photons from atlas you see that + + align:start position:0% +two photons from atlas you see that + + + align:start position:0% +two photons from atlas you see that +there is a slight bump + + align:start position:0% +there is a slight bump + + + align:start position:0% +there is a slight bump +over an enormous background so those are + + align:start position:0% +over an enormous background so those are + + + align:start position:0% +over an enormous background so those are +other sources of diphoton events + + align:start position:0% +other sources of diphoton events + + + align:start position:0% +other sources of diphoton events +which are produced in the hydrogen + + align:start position:0% +which are produced in the hydrogen + + + align:start position:0% +which are produced in the hydrogen +collider but when you subtract those two + + align:start position:0% +collider but when you subtract those two + + + align:start position:0% +collider but when you subtract those two +spectra which is shown here data minus + + align:start position:0% +spectra which is shown here data minus + + + align:start position:0% +spectra which is shown here data minus +background + + align:start position:0% +background + + + align:start position:0% +background +you see this beautiful peak of x to + + align:start position:0% +you see this beautiful peak of x to + + + align:start position:0% +you see this beautiful peak of x to +gamma commandments + + align:start position:0% +gamma commandments + + + align:start position:0% +gamma commandments +similarly x to z z + + align:start position:0% +similarly x to z z + + + align:start position:0% +similarly x to z z +and i put a little star here because one + + align:start position:0% +and i put a little star here because one + + + align:start position:0% +and i put a little star here because one +of the zebras has to be off shell + + align:start position:0% +of the zebras has to be off shell + + + align:start position:0% +of the zebras has to be off shell +the zebra mass is 91 gb the mass of the + + align:start position:0% +the zebra mass is 91 gb the mass of the + + + align:start position:0% +the zebra mass is 91 gb the mass of the +exposure 125 gb + + align:start position:0% +exposure 125 gb + + + align:start position:0% +exposure 125 gb +so 90 plus 91 plus 91 is 928 so one has + + align:start position:0% +so 90 plus 91 plus 91 is 928 so one has + + + align:start position:0% +so 90 plus 91 plus 91 is 928 so one has +to be + + align:start position:0% +to be + + + align:start position:0% +to be +a little off its mass peak + + align:start position:0% +a little off its mass peak + + + align:start position:0% +a little off its mass peak +and then we look at the case into e plus + + align:start position:0% +and then we look at the case into e plus + + + align:start position:0% +and then we look at the case into e plus +and minus + + align:start position:0% +and minus + + + align:start position:0% +and minus +and mu plus mu minus and combination + + align:start position:0% +and mu plus mu minus and combination + + + align:start position:0% +and mu plus mu minus and combination +also so for example for muon events or + + align:start position:0% +also so for example for muon events or + + + align:start position:0% +also so for example for muon events or +for electron events as well + + align:start position:0% +for electron events as well + + + align:start position:0% +for electron events as well +those are shown here and again you have + + align:start position:0% +those are shown here and again you have + + + align:start position:0% +those are shown here and again you have +this beautiful peak + + align:start position:0% +this beautiful peak + + + align:start position:0% +this beautiful peak +consistent with higgs boson at a mass of + + align:start position:0% +consistent with higgs boson at a mass of + + + align:start position:0% +consistent with higgs boson at a mass of +125 gv + + align:start position:0% +125 gv + + + align:start position:0% +125 gv +and again you have other processes which + + align:start position:0% +and again you have other processes which + + + align:start position:0% +and again you have other processes which +contribute to this final state + + align:start position:0% +contribute to this final state + + + align:start position:0% +contribute to this final state +namely the one where you have the four + + align:start position:0% +namely the one where you have the four + + + align:start position:0% +namely the one where you have the four +leptons coming + + align:start position:0% +leptons coming + + + align:start position:0% +leptons coming +from the zebra then itself and or + + align:start position:0% +from the zebra then itself and or + + + align:start position:0% +from the zebra then itself and or +um from a pair of the bosons is shown + + align:start position:0% +um from a pair of the bosons is shown + + + align:start position:0% +um from a pair of the bosons is shown +here + + align:start position:0% +here + + + align:start position:0% +here +there's also processes which mimic the + + align:start position:0% +there's also processes which mimic the + + + align:start position:0% +there's also processes which mimic the +leptons + + align:start position:0% +leptons + + + align:start position:0% +leptons +in the detector those have to be + + align:start position:0% +in the detector those have to be + + + align:start position:0% +in the detector those have to be +evaluated as well and they're typically + + align:start position:0% +evaluated as well and they're typically + + + align:start position:0% +evaluated as well and they're typically +shown here in this plot in green + + align:start position:0% +shown here in this plot in green + + + align:start position:0% +shown here in this plot in green +okay so as you can imagine we can + + align:start position:0% +okay so as you can imagine we can + + + align:start position:0% +okay so as you can imagine we can +measure the cross-section very precisely + + align:start position:0% +measure the cross-section very precisely + + + align:start position:0% +measure the cross-section very precisely +because we can identify those particles + + align:start position:0% +because we can identify those particles + + + align:start position:0% +because we can identify those particles +well but we can also measure the mass + + align:start position:0% +well but we can also measure the mass + + + align:start position:0% +well but we can also measure the mass +and this is shown here + + align:start position:0% +and this is shown here + + + align:start position:0% +and this is shown here +the summary of measurements from atlas + + align:start position:0% +the summary of measurements from atlas + + + align:start position:0% +the summary of measurements from atlas +and cms using + + align:start position:0% +and cms using + + + align:start position:0% +and cms using +those two final states the one with two + + align:start position:0% +those two final states the one with two + + + align:start position:0% +those two final states the one with two +photons or the one with four leptons + + align:start position:0% +photons or the one with four leptons + + + align:start position:0% +photons or the one with four leptons +and you see that measurements are + + align:start position:0% +and you see that measurements are + + + align:start position:0% +and you see that measurements are +generally in agreement + + align:start position:0% +generally in agreement + + + align:start position:0% +generally in agreement +and they can be combined to this + + align:start position:0% +and they can be combined to this + + + align:start position:0% +and they can be combined to this +measurement of 125 gv + + align:start position:0% +measurement of 125 gv + + + align:start position:0% +measurement of 125 gv +and the best the combined value is shown + + align:start position:0% +and the best the combined value is shown + + + align:start position:0% +and the best the combined value is shown +here + + align:start position:0% +here + + + align:start position:0% +here +so this is a precision measurement and + + align:start position:0% +so this is a precision measurement and + + + align:start position:0% +so this is a precision measurement and +since the exposure mass now is the only + + align:start position:0% +since the exposure mass now is the only + + + align:start position:0% +since the exposure mass now is the only +unknown + + align:start position:0% +unknown + + + align:start position:0% +unknown +parameter of the higgs in the standard + + align:start position:0% +parameter of the higgs in the standard + + + align:start position:0% +parameter of the higgs in the standard +model we we know + + align:start position:0% +model we we know + + + align:start position:0% +model we we know +and can check all other properties + + align:start position:0% +and can check all other properties + + + align:start position:0% +and can check all other properties +and one is you know the coupling + + align:start position:0% +and one is you know the coupling + + + align:start position:0% +and one is you know the coupling +strengths to the both on which we just + + align:start position:0% +strengths to the both on which we just + + + align:start position:0% +strengths to the both on which we just +looked at already + + align:start position:0% +looked at already + + + align:start position:0% +looked at already +or the coupling strength to the fermions + + align:start position:0% +or the coupling strength to the fermions + + + align:start position:0% +or the coupling strength to the fermions +so this is two examples one + + align:start position:0% +so this is two examples one + + + align:start position:0% +so this is two examples one +it's showing hicks to taut events + + align:start position:0% +it's showing hicks to taut events + + + align:start position:0% +it's showing hicks to taut events +top last minus and you see again there's + + align:start position:0% +top last minus and you see again there's + + + align:start position:0% +top last minus and you see again there's +a lot of + + align:start position:0% +a lot of + + + align:start position:0% +a lot of +background processes which mimic have + + align:start position:0% +background processes which mimic have + + + align:start position:0% +background processes which mimic have +the same signature the signal + + align:start position:0% +the same signature the signal + + + align:start position:0% +the same signature the signal +but we can find when we subtract the + + align:start position:0% +but we can find when we subtract the + + + align:start position:0% +but we can find when we subtract the +background from the data + + align:start position:0% +background from the data + + + align:start position:0% +background from the data +the nexus of event again at 125 gb + + align:start position:0% +the nexus of event again at 125 gb + + + align:start position:0% +the nexus of event again at 125 gb +so towers themselves decay and the decay + + align:start position:0% +so towers themselves decay and the decay + + + align:start position:0% +so towers themselves decay and the decay +into neutrinos which cannot be measured + + align:start position:0% +into neutrinos which cannot be measured + + + align:start position:0% +into neutrinos which cannot be measured +at this detectors + + align:start position:0% +at this detectors + + + align:start position:0% +at this detectors +are therefore the mass reconstruction is + + align:start position:0% +are therefore the mass reconstruction is + + + align:start position:0% +are therefore the mass reconstruction is +much harder than in the final stage we + + align:start position:0% +much harder than in the final stage we + + + align:start position:0% +much harder than in the final stage we +discussed before + + align:start position:0% +discussed before + + + align:start position:0% +discussed before +that is easier in this final stage here + + align:start position:0% +that is easier in this final stage here + + + align:start position:0% +that is easier in this final stage here +where we have a higgs into two moons + + align:start position:0% +where we have a higgs into two moons + + + align:start position:0% +where we have a higgs into two moons +in the plus c minus the issue here is + + align:start position:0% +in the plus c minus the issue here is + + + align:start position:0% +in the plus c minus the issue here is +that the rate + + align:start position:0% +that the rate + + + align:start position:0% +that the rate +is very small the number of fixed bosons + + align:start position:0% +is very small the number of fixed bosons + + + align:start position:0% +is very small the number of fixed bosons +decaying to be + + align:start position:0% +decaying to be + + + align:start position:0% +decaying to be +very small but there's also a large + + align:start position:0% +very small but there's also a large + + + align:start position:0% +very small but there's also a large +amount of background so again very + + align:start position:0% +amount of background so again very + + + align:start position:0% +amount of background so again very +similar to the hicks to gamma gamma + + align:start position:0% +similar to the hicks to gamma gamma + + + align:start position:0% +similar to the hicks to gamma gamma +finance that we looked before we have a + + align:start position:0% +finance that we looked before we have a + + + align:start position:0% +finance that we looked before we have a +huge amount of background + + align:start position:0% +huge amount of background + + + align:start position:0% +huge amount of background +and here by eyes you don't even see the + + align:start position:0% +and here by eyes you don't even see the + + + align:start position:0% +and here by eyes you don't even see the +bump you see the bump a little bit + + align:start position:0% +bump you see the bump a little bit + + + align:start position:0% +bump you see the bump a little bit +uh when you do data minus background + + align:start position:0% +uh when you do data minus background + + + align:start position:0% +uh when you do data minus background +subtraction + + align:start position:0% +subtraction + + + align:start position:0% +subtraction +so you see this small axis here which is + + align:start position:0% +so you see this small axis here which is + + + align:start position:0% +so you see this small axis here which is +consistent with redundant standard + + align:start position:0% +consistent with redundant standard + + + align:start position:0% +consistent with redundant standard +deviation so + + align:start position:0% +deviation so + + + align:start position:0% +deviation so +the likelihood of the background to + + align:start position:0% +the likelihood of the background to + + + align:start position:0% +the likelihood of the background to +fluctuate without the presence of the + + align:start position:0% +fluctuate without the presence of the + + + align:start position:0% +fluctuate without the presence of the +hex signal + + align:start position:0% +hex signal + + + align:start position:0% +hex signal +is about three standard deviation all + + align:start position:0% +is about three standard deviation all + + + align:start position:0% +is about three standard deviation all +right this information then can be used + + align:start position:0% +right this information then can be used + + + align:start position:0% +right this information then can be used +to interact information about the + + align:start position:0% +to interact information about the + + + align:start position:0% +to interact information about the +couplings itself and this is a beautiful + + align:start position:0% +couplings itself and this is a beautiful + + + align:start position:0% +couplings itself and this is a beautiful +plot here + + align:start position:0% +plot here + + + align:start position:0% +plot here +which shows the x coupling on one axis + + align:start position:0% +which shows the x coupling on one axis + + + align:start position:0% +which shows the x coupling on one axis +either to the fermions or the bodon + + align:start position:0% +either to the fermions or the bodon + + + align:start position:0% +either to the fermions or the bodon +versus the mass of the particle + + align:start position:0% +versus the mass of the particle + + + align:start position:0% +versus the mass of the particle +and so you find your favorite particles + + align:start position:0% +and so you find your favorite particles + + + align:start position:0% +and so you find your favorite particles +the top the w + + align:start position:0% +the top the w + + + align:start position:0% +the top the w +z the bottom the tower and the muon + + align:start position:0% +z the bottom the tower and the muon + + + align:start position:0% +z the bottom the tower and the muon +those are the ones where we can actually + + align:start position:0% +those are the ones where we can actually + + + align:start position:0% +those are the ones where we can actually +measure the coupling um and you see + + align:start position:0% +measure the coupling um and you see + + + align:start position:0% +measure the coupling um and you see +whether or not this is an agreement with + + align:start position:0% +whether or not this is an agreement with + + + align:start position:0% +whether or not this is an agreement with +a standard model which is this + + align:start position:0% +a standard model which is this + + + align:start position:0% +a standard model which is this +blue dotted line here and you see it is + + align:start position:0% +blue dotted line here and you see it is + + + align:start position:0% +blue dotted line here and you see it is +and that plot here tells me that the + + align:start position:0% +and that plot here tells me that the + + + align:start position:0% +and that plot here tells me that the +higgs mechanism + + align:start position:0% +higgs mechanism + + + align:start position:0% +higgs mechanism +is responsible responsible for the mass + + align:start position:0% +is responsible responsible for the mass + + + align:start position:0% +is responsible responsible for the mass +generation of this particle + + align:start position:0% +generation of this particle + + + align:start position:0% +generation of this particle +so it might be that there is a mechanism + + align:start position:0% +so it might be that there is a mechanism + + + align:start position:0% +so it might be that there is a mechanism +which is very similar to the higgs boson + + align:start position:0% +which is very similar to the higgs boson + + + align:start position:0% +which is very similar to the higgs boson +which results in the very same + + align:start position:0% +which results in the very same + + + align:start position:0% +which results in the very same +observations in nature + + align:start position:0% +observations in nature + + + align:start position:0% +observations in nature +um but it's not quite what we have in + + align:start position:0% +um but it's not quite what we have in + + + align:start position:0% +um but it's not quite what we have in +the standard model in order to make + + align:start position:0% +the standard model in order to make + + + align:start position:0% +the standard model in order to make +those statements + + align:start position:0% +those statements + + + align:start position:0% +those statements +one has to improve the size + + align:start position:0% +one has to improve the size + + + align:start position:0% +one has to improve the size +of the error bars here or the + + align:start position:0% +of the error bars here or the + + + align:start position:0% +of the error bars here or the +statistical significance or the + + align:start position:0% +statistical significance or the + + + align:start position:0% +statistical significance or the +significance of the measurements + + align:start position:0% +significance of the measurements + + + align:start position:0% +significance of the measurements +that is part of our program that's what + + align:start position:0% +that is part of our program that's what + + + align:start position:0% +that is part of our program that's what +we're trying to do + + align:start position:0% +we're trying to do + + + align:start position:0% +we're trying to do +all right in summary again this is a + + align:start position:0% +all right in summary again this is a + + + align:start position:0% +all right in summary again this is a +very high level summary so we measured + + align:start position:0% +very high level summary so we measured + + + align:start position:0% +very high level summary so we measured +the mass + + align:start position:0% +the mass + + + align:start position:0% +the mass +we measured the spin and cp of exposure + + align:start position:0% +we measured the spin and cp of exposure + + + align:start position:0% +we measured the spin and cp of exposure +we measured the coupling to the z the w + + align:start position:0% +we measured the coupling to the z the w + + + align:start position:0% +we measured the coupling to the z the w +the top the bottom the tau and the muon + + align:start position:0% +the top the bottom the tau and the muon + + + align:start position:0% +the top the bottom the tau and the muon +we have not been able to measure the + + align:start position:0% +we have not been able to measure the + + + align:start position:0% +we have not been able to measure the +coupling to lighter quark masses + + align:start position:0% +coupling to lighter quark masses + + + align:start position:0% +coupling to lighter quark masses +strange charm up and down + + align:start position:0% +strange charm up and down + + + align:start position:0% +strange charm up and down +we have not been able to measure the + + align:start position:0% +we have not been able to measure the + + + align:start position:0% +we have not been able to measure the +coupling to the lx one + + align:start position:0% +coupling to the lx one + + + align:start position:0% +coupling to the lx one +that would be spectacular and we have + + align:start position:0% +that would be spectacular and we have + + + align:start position:0% +that would be spectacular and we have +not measured the coupling to itself so + + align:start position:0% +not measured the coupling to itself so + + + align:start position:0% +not measured the coupling to itself so +in the standard model the higgs boson + + align:start position:0% +in the standard model the higgs boson + + + align:start position:0% +in the standard model the higgs boson +can couple to itself + + align:start position:0% +can couple to itself + + + align:start position:0% +can couple to itself +so we have diagrams which look like this + + align:start position:0% +so we have diagrams which look like this + + + align:start position:0% +so we have diagrams which look like this +x x x and we have not been able to + + align:start position:0% +x x x and we have not been able to + + + align:start position:0% +x x x and we have not been able to +measure this + + align:start position:0% +measure this + + + align:start position:0% +measure this +this is not free in the standard model + + align:start position:0% +this is not free in the standard model + + + align:start position:0% +this is not free in the standard model +and this would be you know + + align:start position:0% +and this would be you know + + + align:start position:0% +and this would be you know +closing the argument that the higgs + + align:start position:0% +closing the argument that the higgs + + + align:start position:0% +closing the argument that the higgs +boson requires mass + + align:start position:0% +boson requires mass + + + align:start position:0% +boson requires mass +or the higgs boson is the particle + + align:start position:0% +or the higgs boson is the particle + + + align:start position:0% +or the higgs boson is the particle +predicted in the standard model + + align:start position:0% +predicted in the standard model + + + align:start position:0% +predicted in the standard model +giving mass to w and z goes on + + align:start position:0% + + + + align:start position:0% + +if you want you can the strength of the + + align:start position:0% +if you want you can the strength of the + + + align:start position:0% +if you want you can the strength of the +coupling here is this lambda + + align:start position:0% +coupling here is this lambda + + + align:start position:0% +coupling here is this lambda +this is the lambda term in our potential + + align:start position:0% +this is the lambda term in our potential + + + align:start position:0% +this is the lambda term in our potential +so that's what we are trying to measure + + align:start position:0% +so that's what we are trying to measure + + + align:start position:0% +so that's what we are trying to measure +in the future + + align:start position:0% +in the future + + + align:start position:0% +in the future +but there's more open questions um maybe + + align:start position:0% +but there's more open questions um maybe + + + align:start position:0% +but there's more open questions um maybe +there's more than + + align:start position:0% +there's more than + + + align:start position:0% +there's more than +one exposure on the higgs adding one + + align:start position:0% +one exposure on the higgs adding one + + + align:start position:0% +one exposure on the higgs adding one +duplet to the standard model with this + + align:start position:0% +duplet to the standard model with this + + + align:start position:0% +duplet to the standard model with this +potential + + align:start position:0% +potential + + + align:start position:0% +potential +is one possible solution to the problem + + align:start position:0% +is one possible solution to the problem + + + align:start position:0% +is one possible solution to the problem +of generating mars + + align:start position:0% +of generating mars + + + align:start position:0% +of generating mars +but you could have very well added two + + align:start position:0% +but you could have very well added two + + + align:start position:0% +but you could have very well added two +or n + + align:start position:0% +or n + + + align:start position:0% +or n +or triplets or more complicated things + + align:start position:0% +or triplets or more complicated things + + + align:start position:0% +or triplets or more complicated things +and so the question is + + align:start position:0% +and so the question is + + + align:start position:0% +and so the question is +are those maybe realized in nature or + + align:start position:0% +are those maybe realized in nature or + + + align:start position:0% +are those maybe realized in nature or +not + + align:start position:0% +not + + + align:start position:0% +not +um + + align:start position:0% + + + + align:start position:0% + +will more precision tell us something + + align:start position:0% +will more precision tell us something + + + align:start position:0% +will more precision tell us something +about the higgs boson + + align:start position:0% +about the higgs boson + + + align:start position:0% +about the higgs boson +are there the case of the higgs bosons + + align:start position:0% +are there the case of the higgs bosons + + + align:start position:0% +are there the case of the higgs bosons +of non-standard model particles for + + align:start position:0% +of non-standard model particles for + + + align:start position:0% +of non-standard model particles for +example the higgs boson decaying into + + align:start position:0% +example the higgs boson decaying into + + + align:start position:0% +example the higgs boson decaying into +those guys here which could be evidence + + align:start position:0% +those guys here which could be evidence + + + align:start position:0% +those guys here which could be evidence +for dark matter + + align:start position:0% +for dark matter + + + align:start position:0% +for dark matter +we have looks we have not seen this but + + align:start position:0% +we have looks we have not seen this but + + + align:start position:0% +we have looks we have not seen this but +more precision might give us a different + + align:start position:0% +more precision might give us a different + + + align:start position:0% +more precision might give us a different +answer + + align:start position:0% +answer + + + align:start position:0% +answer +so that's basically the status or the + + align:start position:0% +so that's basically the status or the + + + align:start position:0% +so that's basically the status or the +summary of where we are with the higgs + + align:start position:0% +summary of where we are with the higgs + + + align:start position:0% +summary of where we are with the higgs +boson again much more can be said about + + align:start position:0% +boson again much more can be said about + + + align:start position:0% +boson again much more can be said about +that + + align:start position:0% +that + + + align:start position:0% +that +and you will see this every now and then + + align:start position:0% +and you will see this every now and then + + + align:start position:0% +and you will see this every now and then +in seminars at mit + + align:start position:0% +in seminars at mit + + + align:start position:0% +in seminars at mit +or other places + + align:start position:0% +or other places + + + align:start position:0% +or other places +you \ No newline at end of file diff --git a/56vQ0S2eAjw.txt b/56vQ0S2eAjw.txt new file mode 100644 index 0000000000000000000000000000000000000000..d197300451ad1ea4433a43b548d3466b930b921a --- /dev/null +++ b/56vQ0S2eAjw.txt @@ -0,0 +1,4235 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT OpenCourseWare continue to + + align:start position:0% +will help MIT OpenCourseWare continue to + + + align:start position:0% +will help MIT OpenCourseWare continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or view additional + + align:start position:0% +to make a donation or view additional + + + align:start position:0% +to make a donation or view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% +visit MIT opencourseware at ocw.mit.edu + + + align:start position:0% +visit MIT opencourseware at ocw.mit.edu +today what I want to do is in the within + + align:start position:0% +today what I want to do is in the within + + + align:start position:0% +today what I want to do is in the within +the lexicon is tell you about nature's + + align:start position:0% +the lexicon is tell you about nature's + + + align:start position:0% +the lexicon is tell you about nature's +most spectacularly beautiful cofactors + + align:start position:0% +most spectacularly beautiful cofactors + + + align:start position:0% +most spectacularly beautiful cofactors +and these are formed from vitamin b12 + + align:start position:0% +and these are formed from vitamin b12 + + + align:start position:0% +and these are formed from vitamin b12 +which you find in your vitamin bottle ok + + align:start position:0% +which you find in your vitamin bottle ok + + + align:start position:0% +which you find in your vitamin bottle ok +so what is the structure of vitamin b12 + + align:start position:0% +so what is the structure of vitamin b12 + + + align:start position:0% +so what is the structure of vitamin b12 +and why do I say there it's + + align:start position:0% +and why do I say there it's + + + align:start position:0% +and why do I say there it's +spectacularly beautiful so it's very + + align:start position:0% +spectacularly beautiful so it's very + + + align:start position:0% +spectacularly beautiful so it's very +hard to see you but if you look at the + + align:start position:0% +hard to see you but if you look at the + + + align:start position:0% +hard to see you but if you look at the +structure of this where have you seen a + + align:start position:0% +structure of this where have you seen a + + + align:start position:0% +structure of this where have you seen a +molecule this complicated with five + + align:start position:0% +molecule this complicated with five + + + align:start position:0% +molecule this complicated with five +membered rings each of which has a + + align:start position:0% +membered rings each of which has a + + + align:start position:0% +membered rings each of which has a +nitrogen in this you've seen this when + + align:start position:0% +nitrogen in this you've seen this when + + + align:start position:0% +nitrogen in this you've seen this when +you studied hemoglobin and you think + + align:start position:0% +you studied hemoglobin and you think + + + align:start position:0% +you studied hemoglobin and you think +about heme and protoporphyrin 9 if you + + align:start position:0% +about heme and protoporphyrin 9 if you + + + align:start position:0% +about heme and protoporphyrin 9 if you +look at the biosynthetic pathway of heme + + align:start position:0% +look at the biosynthetic pathway of heme + + + align:start position:0% +look at the biosynthetic pathway of heme +or branch point of that pathway is to + + align:start position:0% +or branch point of that pathway is to + + + align:start position:0% +or branch point of that pathway is to +make this ring which is found in + + align:start position:0% +make this ring which is found in + + + align:start position:0% +make this ring which is found in +adenosylcobalamin and methylcobalamin + + align:start position:0% +adenosylcobalamin and methylcobalamin + + + align:start position:0% +adenosylcobalamin and methylcobalamin +which is what we're going to be focusing + + align:start position:0% +which is what we're going to be focusing + + + align:start position:0% +which is what we're going to be focusing +on today and this ring is called the + + align:start position:0% +on today and this ring is called the + + + align:start position:0% +on today and this ring is called the +Koren ring so what I want to do is + + align:start position:0% +Koren ring so what I want to do is + + + align:start position:0% +Koren ring so what I want to do is +introduce you a little bit to this Koren + + align:start position:0% +introduce you a little bit to this Koren + + + align:start position:0% +introduce you a little bit to this Koren +ring and what's unusual about it + + align:start position:0% +ring and what's unusual about it + + + align:start position:0% +ring and what's unusual about it +compared to pro tempore for nine that + + align:start position:0% +compared to pro tempore for nine that + + + align:start position:0% +compared to pro tempore for nine that +you've been seen before you've seen + + align:start position:0% +you've been seen before you've seen + + + align:start position:0% +you've been seen before you've seen +before so the vitamin as in the case of + + align:start position:0% +before so the vitamin as in the case of + + + align:start position:0% +before so the vitamin as in the case of +all vitamins that we've talked about + + align:start position:0% +all vitamins that we've talked about + + + align:start position:0% +all vitamins that we've talked about +over the course of the semester is not + + align:start position:0% +over the course of the semester is not + + + align:start position:0% +over the course of the semester is not +the actual cofactor used in the + + align:start position:0% +the actual cofactor used in the + + + align:start position:0% +the actual cofactor used in the +enzymatic transformation the vitamin + + align:start position:0% +enzymatic transformation the vitamin + + + align:start position:0% +enzymatic transformation the vitamin +which in this case would have this group + + align:start position:0% +which in this case would have this group + + + align:start position:0% +which in this case would have this group +replaced with cyanide is vitamin b12 the + + align:start position:0% +replaced with cyanide is vitamin b12 the + + + align:start position:0% +replaced with cyanide is vitamin b12 the +actual cofactors that bind to the enzyme + + align:start position:0% +actual cofactors that bind to the enzyme + + + align:start position:0% +actual cofactors that bind to the enzyme +have that cyanide replaced with either a + + align:start position:0% +have that cyanide replaced with either a + + + align:start position:0% +have that cyanide replaced with either a +methyl group and that's called + + align:start position:0% +methyl group and that's called + + + align:start position:0% +methyl group and that's called +methylcobalamin or they have it replaced + + align:start position:0% +methylcobalamin or they have it replaced + + + align:start position:0% +methylcobalamin or they have it replaced +with five prime deoxyadenosine and + + align:start position:0% +with five prime deoxyadenosine and + + + align:start position:0% +with five prime deoxyadenosine and +that's called adenosylcobalamin and so + + align:start position:0% +that's called adenosylcobalamin and so + + + align:start position:0% +that's called adenosylcobalamin and so +the rest of the molecule is exactly the + + align:start position:0% +the rest of the molecule is exactly the + + + align:start position:0% +the rest of the molecule is exactly the +same the + + align:start position:0% +same the + + + align:start position:0% +same the +only thing that's distinct is the axial + + align:start position:0% +only thing that's distinct is the axial + + + align:start position:0% +only thing that's distinct is the axial +again so you remember from your + + align:start position:0% +again so you remember from your + + + align:start position:0% +again so you remember from your +transition metal chemistry you had when + + align:start position:0% +transition metal chemistry you had when + + + align:start position:0% +transition metal chemistry you had when +you were freshmen that here you have a + + align:start position:0% +you were freshmen that here you have a + + + align:start position:0% +you were freshmen that here you have a +cobalt 3 and it's coordinated to foreign + + align:start position:0% +cobalt 3 and it's coordinated to foreign + + + align:start position:0% +cobalt 3 and it's coordinated to foreign +nitrogen's okay so this would be the + + align:start position:0% +nitrogen's okay so this would be the + + + align:start position:0% +nitrogen's okay so this would be the +equatorial plane and we're going to draw + + align:start position:0% +equatorial plane and we're going to draw + + + align:start position:0% +equatorial plane and we're going to draw +it like this + + align:start position:0% +it like this + + + align:start position:0% +it like this +subsequently because you can see how + + align:start position:0% +subsequently because you can see how + + + align:start position:0% +subsequently because you can see how +complicated this molecule is in the + + align:start position:0% +complicated this molecule is in the + + + align:start position:0% +complicated this molecule is in the +metal sits right and this mitt this + + align:start position:0% +metal sits right and this mitt this + + + align:start position:0% +metal sits right and this mitt this +plane but you can see that you don't + + align:start position:0% +plane but you can see that you don't + + + align:start position:0% +plane but you can see that you don't +have complete saturation of these parol + + align:start position:0% +have complete saturation of these parol + + + align:start position:0% +have complete saturation of these parol +type rings so there's some pucker and + + align:start position:0% +type rings so there's some pucker and + + + align:start position:0% +type rings so there's some pucker and +contrast with hymns which are very flat + + align:start position:0% +contrast with hymns which are very flat + + + align:start position:0% +contrast with hymns which are very flat +and then these are called equatorial + + align:start position:0% +and then these are called equatorial + + + align:start position:0% +and then these are called equatorial +ligands and then you have axial ligands + + align:start position:0% +ligands and then you have axial ligands + + + align:start position:0% +ligands and then you have axial ligands +and so there are a number of things that + + align:start position:0% +and so there are a number of things that + + + align:start position:0% +and so there are a number of things that +again that I wanted to point out that + + align:start position:0% +again that I wanted to point out that + + + align:start position:0% +again that I wanted to point out that +are unusual about b12 one is the fact + + align:start position:0% +are unusual about b12 one is the fact + + + align:start position:0% +are unusual about b12 one is the fact +that the Corrin ring again is much more + + align:start position:0% +that the Corrin ring again is much more + + + align:start position:0% +that the Corrin ring again is much more +reduced than a parole ring and so it's + + align:start position:0% +reduced than a parole ring and so it's + + + align:start position:0% +reduced than a parole ring and so it's +puckered and if you look at the + + align:start position:0% +puckered and if you look at the + + + align:start position:0% +puckered and if you look at the +structure of I mean the visible spectrum + + align:start position:0% +structure of I mean the visible spectrum + + + align:start position:0% +structure of I mean the visible spectrum +are you use your eye and use your + + align:start position:0% +are you use your eye and use your + + + align:start position:0% +are you use your eye and use your +eyeball method you see that + + align:start position:0% +eyeball method you see that + + + align:start position:0% +eyeball method you see that +cyanocobalamin is bright purple if you + + align:start position:0% +cyanocobalamin is bright purple if you + + + align:start position:0% +cyanocobalamin is bright purple if you +replace this our group with a methyl + + align:start position:0% +replace this our group with a methyl + + + align:start position:0% +replace this our group with a methyl +group + + align:start position:0% +group + + + align:start position:0% +group +this color turns out to be sort of + + align:start position:0% +this color turns out to be sort of + + + align:start position:0% +this color turns out to be sort of +yellow orange and if you replace this + + align:start position:0% +yellow orange and if you replace this + + + align:start position:0% +yellow orange and if you replace this +with fiber mt.gox adenosine it turns out + + align:start position:0% +with fiber mt.gox adenosine it turns out + + + align:start position:0% +with fiber mt.gox adenosine it turns out +to be pink so that's why I say that this + + align:start position:0% +to be pink so that's why I say that this + + + align:start position:0% +to be pink so that's why I say that this +is nature's most spectacular beautiful + + align:start position:0% +is nature's most spectacular beautiful + + + align:start position:0% +is nature's most spectacular beautiful +cofactor so the other thing is you have + + align:start position:0% +cofactor so the other thing is you have + + + align:start position:0% +cofactor so the other thing is you have +two axial ligands I just introduced you + + align:start position:0% +two axial ligands I just introduced you + + + align:start position:0% +two axial ligands I just introduced you +to these guys on the top face but what + + align:start position:0% +to these guys on the top face but what + + + align:start position:0% +to these guys on the top face but what +you also see on the bottom face the + + align:start position:0% +you also see on the bottom face the + + + align:start position:0% +you also see on the bottom face the +bottom axial ligand is this unusual + + align:start position:0% +bottom axial ligand is this unusual + + + align:start position:0% +bottom axial ligand is this unusual +structure which is called dimethyl + + align:start position:0% +structure which is called dimethyl + + + align:start position:0% +structure which is called dimethyl +benzene midazolam and it's attached to a + + align:start position:0% +benzene midazolam and it's attached to a + + + align:start position:0% +benzene midazolam and it's attached to a +ribose but the unusual thing is in most + + align:start position:0% +ribose but the unusual thing is in most + + + align:start position:0% +ribose but the unusual thing is in most +nucleus IDEs that you've encountered + + align:start position:0% +nucleus IDEs that you've encountered + + + align:start position:0% +nucleus IDEs that you've encountered +like ATP this configuration is in the + + align:start position:0% +like ATP this configuration is in the + + + align:start position:0% +like ATP this configuration is in the +beta position it's on the top face of + + align:start position:0% +beta position it's on the top face of + + + align:start position:0% +beta position it's on the top face of +the sugar in here it's in the Alpha + + align:start position:0% +the sugar in here it's in the Alpha + + + align:start position:0% +the sugar in here it's in the Alpha +position so that's distinct and the + + align:start position:0% +position so that's distinct and the + + + align:start position:0% +position so that's distinct and the +other thing that's distinct is the + + align:start position:0% +other thing that's distinct is the + + + align:start position:0% +other thing that's distinct is the +decorations around the sidechain + + align:start position:0% +decorations around the sidechain + + + align:start position:0% +decorations around the sidechain +compared to what you see in porphyrins + + align:start position:0% +compared to what you see in porphyrins + + + align:start position:0% +compared to what you see in porphyrins +so this is a cofactor we're going to be + + align:start position:0% +so this is a cofactor we're going to be + + + align:start position:0% +so this is a cofactor we're going to be +talking about and one of the questions + + align:start position:0% +talking about and one of the questions + + + align:start position:0% +talking about and one of the questions +that that you're interested in is where + + align:start position:0% +that that you're interested in is where + + + align:start position:0% +that that you're interested in is where +do we find these cofactors and + + align:start position:0% +do we find these cofactors and + + + align:start position:0% +do we find these cofactors and +metabolism in a mammalian metabolism + + align:start position:0% +metabolism in a mammalian metabolism + + + align:start position:0% +metabolism in a mammalian metabolism +they're very the appearance of these + + align:start position:0% +they're very the appearance of these + + + align:start position:0% +they're very the appearance of these +cofactors is quite limited so the only + + align:start position:0% +cofactors is quite limited so the only + + + align:start position:0% +cofactors is quite limited so the only +place you see it in metabolism in + + align:start position:0% +place you see it in metabolism in + + + align:start position:0% +place you see it in metabolism in +mammalian systems is you see + + align:start position:0% +mammalian systems is you see + + + align:start position:0% +mammalian systems is you see +methylcobalamin ok where this is a + + align:start position:0% +methylcobalamin ok where this is a + + + align:start position:0% +methylcobalamin ok where this is a +methyl group in formation of the amino + + align:start position:0% +methyl group in formation of the amino + + + align:start position:0% +methyl group in formation of the amino +acid Matheny and so the methyl group + + align:start position:0% +acid Matheny and so the methyl group + + + align:start position:0% +acid Matheny and so the methyl group +from methionine I'll show you briefly at + + align:start position:0% +from methionine I'll show you briefly at + + + align:start position:0% +from methionine I'll show you briefly at +the very end of this little presentation + + align:start position:0% +the very end of this little presentation + + + align:start position:0% +the very end of this little presentation +comes from this methyl group you use + + align:start position:0% +comes from this methyl group you use + + + align:start position:0% +comes from this methyl group you use +Dennis O cobalamin in odd chain fatty + + align:start position:0% +Dennis O cobalamin in odd chain fatty + + + align:start position:0% +Dennis O cobalamin in odd chain fatty +acid metabolism so you have fatty acids + + align:start position:0% +acid metabolism so you have fatty acids + + + align:start position:0% +acid metabolism so you have fatty acids +that are either either at our odds a + + align:start position:0% +that are either either at our odds a + + + align:start position:0% +that are either either at our odds a +no-brain ones down you get proprio Co + + align:start position:0% +no-brain ones down you get proprio Co + + + align:start position:0% +no-brain ones down you get proprio Co +way the proprio Co way through a series + + align:start position:0% +way the proprio Co way through a series + + + align:start position:0% +way the proprio Co way through a series +of steps is converted into Melanie Ocoee + + align:start position:0% +of steps is converted into Melanie Ocoee + + + align:start position:0% +of steps is converted into Melanie Ocoee +which then gets converted to + + align:start position:0% +which then gets converted to + + + align:start position:0% +which then gets converted to +succinylcholine + + align:start position:0% +succinylcholine + + + align:start position:0% +succinylcholine +in to the TCA cycle and in that pathway + + align:start position:0% +in to the TCA cycle and in that pathway + + + align:start position:0% +in to the TCA cycle and in that pathway +you use an enzyme a mutase that uses + + align:start position:0% +you use an enzyme a mutase that uses + + + align:start position:0% +you use an enzyme a mutase that uses +adenosylcobalamin we'll talk briefly + + align:start position:0% +adenosylcobalamin we'll talk briefly + + + align:start position:0% +adenosylcobalamin we'll talk briefly +about the chemistry of adenosylcobalamin + + align:start position:0% +about the chemistry of adenosylcobalamin + + + align:start position:0% +about the chemistry of adenosylcobalamin +also methylcobalamin ok so there were a + + align:start position:0% +also methylcobalamin ok so there were a + + + align:start position:0% +also methylcobalamin ok so there were a +few things that i wanted to say about + + align:start position:0% +few things that i wanted to say about + + + align:start position:0% +few things that i wanted to say about +some generalizations that i wanted to + + align:start position:0% +some generalizations that i wanted to + + + align:start position:0% +some generalizations that i wanted to +make about these cofactors and the first + + align:start position:0% +make about these cofactors and the first + + + align:start position:0% +make about these cofactors and the first +one is that again the Corrin ring is + + align:start position:0% +one is that again the Corrin ring is + + + align:start position:0% +one is that again the Corrin ring is +much more reduced than the parol ring + + align:start position:0% +much more reduced than the parol ring + + + align:start position:0% +much more reduced than the parol ring +that you see in protoporphyrin 9 which + + align:start position:0% +that you see in protoporphyrin 9 which + + + align:start position:0% +that you see in protoporphyrin 9 which +you've seen in hemoglobin before the + + align:start position:0% +you've seen in hemoglobin before the + + + align:start position:0% +you've seen in hemoglobin before the +second thing is that you have this + + align:start position:0% +second thing is that you have this + + + align:start position:0% +second thing is that you have this +unusual dimethyl benzyl midazolam in + + align:start position:0% +unusual dimethyl benzyl midazolam in + + + align:start position:0% +unusual dimethyl benzyl midazolam in +which you see nowhere else in cofactor + + align:start position:0% +which you see nowhere else in cofactor + + + align:start position:0% +which you see nowhere else in cofactor +chemistry it's only found in this + + align:start position:0% +chemistry it's only found in this + + + align:start position:0% +chemistry it's only found in this +particular cofactor the second thing + + align:start position:0% +particular cofactor the second thing + + + align:start position:0% +particular cofactor the second thing +which I think is the most amazing is + + align:start position:0% +which I think is the most amazing is + + + align:start position:0% +which I think is the most amazing is +that what you see if you + + align:start position:0% +that what you see if you + + + align:start position:0% +that what you see if you +look back here is that you have if this + + align:start position:0% +look back here is that you have if this + + + align:start position:0% +look back here is that you have if this +is a methyl group or this is this + + align:start position:0% +is a methyl group or this is this + + + align:start position:0% +is a methyl group or this is this +five-prime deoxyadenosine you have a + + align:start position:0% +five-prime deoxyadenosine you have a + + + align:start position:0% +five-prime deoxyadenosine you have a +carbon cobalt bond well this was + + align:start position:0% +carbon cobalt bond well this was + + + align:start position:0% +carbon cobalt bond well this was +discovered in the 1950s and the first + + align:start position:0% +discovered in the 1950s and the first + + + align:start position:0% +discovered in the 1950s and the first +structure was solved of this molecule by + + align:start position:0% +structure was solved of this molecule by + + + align:start position:0% +structure was solved of this molecule by +Dorothy crow for Hodgkin in 1964 and she + + align:start position:0% +Dorothy crow for Hodgkin in 1964 and she + + + align:start position:0% +Dorothy crow for Hodgkin in 1964 and she +won the Nobel Prize did this work no + + align:start position:0% +won the Nobel Prize did this work no + + + align:start position:0% +won the Nobel Prize did this work no +chemists had ever seen a carbon cobalt + + align:start position:0% +chemists had ever seen a carbon cobalt + + + align:start position:0% +chemists had ever seen a carbon cobalt +bond and they thought in fact + + align:start position:0% +bond and they thought in fact + + + align:start position:0% +bond and they thought in fact +biochemists were crazy that they even + + align:start position:0% +biochemists were crazy that they even + + + align:start position:0% +biochemists were crazy that they even +proposed such a structure so this + + align:start position:0% +proposed such a structure so this + + + align:start position:0% +proposed such a structure so this +structure and we'll see that this this + + align:start position:0% +structure and we'll see that this this + + + align:start position:0% +structure and we'll see that this this +is where all the chemistry happens is + + align:start position:0% +is where all the chemistry happens is + + + align:start position:0% +is where all the chemistry happens is +completely unique and people spent 25 + + align:start position:0% +completely unique and people spent 25 + + + align:start position:0% +completely unique and people spent 25 +years figuring out how this cofactor it + + align:start position:0% +years figuring out how this cofactor it + + + align:start position:0% +years figuring out how this cofactor it +actually work to do the transformations + + align:start position:0% +actually work to do the transformations + + + align:start position:0% +actually work to do the transformations +that I'll very briefly introduce you to + + align:start position:0% +that I'll very briefly introduce you to + + + align:start position:0% +that I'll very briefly introduce you to +so this is the first example of a carbon + + align:start position:0% +so this is the first example of a carbon + + + align:start position:0% +so this is the first example of a carbon +cobalt and we'll see that cobalt is in + + align:start position:0% +cobalt and we'll see that cobalt is in + + + align:start position:0% +cobalt and we'll see that cobalt is in +the plus 3 oxidation state bond so it's + + align:start position:0% +the plus 3 oxidation state bond so it's + + + align:start position:0% +the plus 3 oxidation state bond so it's +the first organo metallic cofactor and + + align:start position:0% +the first organo metallic cofactor and + + + align:start position:0% +the first organo metallic cofactor and +what people also found by studying this + + align:start position:0% +what people also found by studying this + + + align:start position:0% +what people also found by studying this +molecule is that the cobalt can actually + + align:start position:0% +molecule is that the cobalt can actually + + + align:start position:0% +molecule is that the cobalt can actually +exist in 3 oxidation state it can exist + + align:start position:0% +exist in 3 oxidation state it can exist + + + align:start position:0% +exist in 3 oxidation state it can exist +in the Cobell one state we're in the DZ + + align:start position:0% +in the Cobell one state we're in the DZ + + + align:start position:0% +in the Cobell one state we're in the DZ +squared orbital if you don't remember + + align:start position:0% +squared orbital if you don't remember + + + align:start position:0% +squared orbital if you don't remember +what a DZ squared orbital is you need to + + align:start position:0% +what a DZ squared orbital is you need to + + + align:start position:0% +what a DZ squared orbital is you need to +go back and look at your freshman + + align:start position:0% +go back and look at your freshman + + + align:start position:0% +go back and look at your freshman +chemistry you have two electrons and it + + align:start position:0% +chemistry you have two electrons and it + + + align:start position:0% +chemistry you have two electrons and it +turns out that cobalt 1 is a super + + align:start position:0% +turns out that cobalt 1 is a super + + + align:start position:0% +turns out that cobalt 1 is a super +nucleophile and we'll see that that + + align:start position:0% +nucleophile and we'll see that that + + + align:start position:0% +nucleophile and we'll see that that +plays a key role in the chemistry and so + + align:start position:0% +plays a key role in the chemistry and so + + + align:start position:0% +plays a key role in the chemistry and so +again this is the cobalt the D we're + + align:start position:0% +again this is the cobalt the D we're + + + align:start position:0% +again this is the cobalt the D we're +only looking at one of the orbit + + align:start position:0% +only looking at one of the orbit + + + align:start position:0% +only looking at one of the orbit +orbitals of the cobalt on the other hand + + align:start position:0% +orbitals of the cobalt on the other hand + + + align:start position:0% +orbitals of the cobalt on the other hand +in adenosine and this is found in methyl + + align:start position:0% +in adenosine and this is found in methyl + + + align:start position:0% +in adenosine and this is found in methyl +this is going to be used in + + align:start position:0% +this is going to be used in + + + align:start position:0% +this is going to be used in +methylcobalamin so when you have a + + align:start position:0% +methylcobalamin so when you have a + + + align:start position:0% +methylcobalamin so when you have a +methyl group as the axial again you're + + align:start position:0% +methyl group as the axial again you're + + + align:start position:0% +methyl group as the axial again you're +going to use cobalt in this oxidation + + align:start position:0% +going to use cobalt in this oxidation + + + align:start position:0% +going to use cobalt in this oxidation +state which is the plus 1 state for + + align:start position:0% +state which is the plus 1 state for + + + align:start position:0% +state which is the plus 1 state for +almost all other b12 dependent reactions + + align:start position:0% +almost all other b12 dependent reactions + + + align:start position:0% +almost all other b12 dependent reactions +you have cobalt 2 which has you + + align:start position:0% +you have cobalt 2 which has you + + + align:start position:0% +you have cobalt 2 which has you +lausanne electrons he have one only one + + align:start position:0% +lausanne electrons he have one only one + + + align:start position:0% +lausanne electrons he have one only one +electron by itself in its DZ squared + + align:start position:0% +electron by itself in its DZ squared + + + align:start position:0% +electron by itself in its DZ squared +orbital and this really dictates the + + align:start position:0% +orbital and this really dictates the + + + align:start position:0% +orbital and this really dictates the +chemistry and so this is found in + + align:start position:0% +chemistry and so this is found in + + + align:start position:0% +chemistry and so this is found in +adenosylcobalamin chemistry and then in + + align:start position:0% +adenosylcobalamin chemistry and then in + + + align:start position:0% +adenosylcobalamin chemistry and then in +the resting state you have cobalt 3 and + + align:start position:0% +the resting state you have cobalt 3 and + + + align:start position:0% +the resting state you have cobalt 3 and +cobalt 3 has none of the electrons in + + align:start position:0% +cobalt 3 has none of the electrons in + + + align:start position:0% +cobalt 3 has none of the electrons in +the DZ squared orbital and this is + + align:start position:0% +the DZ squared orbital and this is + + + align:start position:0% +the DZ squared orbital and this is +basically the resting state this most + + align:start position:0% +basically the resting state this most + + + align:start position:0% +basically the resting state this most +stable state where you find this + + align:start position:0% +stable state where you find this + + + align:start position:0% +stable state where you find this +cofactor + + align:start position:0% +cofactor + + + align:start position:0% +cofactor +so in cyano cobalamin which is vitamin + + align:start position:0% +so in cyano cobalamin which is vitamin + + + align:start position:0% +so in cyano cobalamin which is vitamin +b12 the cobalt is in the plus 3 + + align:start position:0% +b12 the cobalt is in the plus 3 + + + align:start position:0% +b12 the cobalt is in the plus 3 +oxidation state ok so what we're gonna + + align:start position:0% +oxidation state ok so what we're gonna + + + align:start position:0% +oxidation state ok so what we're gonna +see very briefly we're not spending much + + align:start position:0% +see very briefly we're not spending much + + + align:start position:0% +see very briefly we're not spending much +time on this is the cobalt 1 state it's + + align:start position:0% +time on this is the cobalt 1 state it's + + + align:start position:0% +time on this is the cobalt 1 state it's +a super good nucleophile that affects + + align:start position:0% +a super good nucleophile that affects + + + align:start position:0% +a super good nucleophile that affects +the chemistry the cobalt 2 state has one + + align:start position:0% +the chemistry the cobalt 2 state has one + + + align:start position:0% +the chemistry the cobalt 2 state has one +unpaired electron + + align:start position:0% +unpaired electron + + + align:start position:0% +unpaired electron +you haven't been introduced to chemistry + + align:start position:0% +you haven't been introduced to chemistry + + + align:start position:0% +you haven't been introduced to chemistry +with one unpaired electron which is + + align:start position:0% +with one unpaired electron which is + + + align:start position:0% +with one unpaired electron which is +radical chemistry that most people don't + + align:start position:0% +radical chemistry that most people don't + + + align:start position:0% +radical chemistry that most people don't +spend a lot of time talking about + + align:start position:0% +spend a lot of time talking about + + + align:start position:0% +spend a lot of time talking about +adenosylcobalamin because it's radicals + + align:start position:0% +adenosylcobalamin because it's radicals + + + align:start position:0% +adenosylcobalamin because it's radicals +and they don't learn much about radicals + + align:start position:0% +and they don't learn much about radicals + + + align:start position:0% +and they don't learn much about radicals +in introductory organic chemistry but + + align:start position:0% +in introductory organic chemistry but + + + align:start position:0% +in introductory organic chemistry but +i'll show you briefly how the enzymes + + align:start position:0% +i'll show you briefly how the enzymes + + + align:start position:0% +i'll show you briefly how the enzymes +work they use this cobalt to state the + + align:start position:0% +work they use this cobalt to state the + + + align:start position:0% +work they use this cobalt to state the +other thing I wanted to mention was that + + align:start position:0% +other thing I wanted to mention was that + + + align:start position:0% +other thing I wanted to mention was that +the colors and so if you try want to + + align:start position:0% +the colors and so if you try want to + + + align:start position:0% +the colors and so if you try want to +understand how these cofactors work the + + align:start position:0% +understand how these cofactors work the + + + align:start position:0% +understand how these cofactors work the +different number of electrons govern + + align:start position:0% +different number of electrons govern + + + align:start position:0% +different number of electrons govern +what colors you can end up seeing and + + align:start position:0% +what colors you can end up seeing and + + + align:start position:0% +what colors you can end up seeing and +again I always use this as an example on + + align:start position:0% +again I always use this as an example on + + + align:start position:0% +again I always use this as an example on +mi t--'s campus in the spring cobalt 2 + + align:start position:0% +mi t--'s campus in the spring cobalt 2 + + + align:start position:0% +mi t--'s campus in the spring cobalt 2 +has spectacular orange color like the + + align:start position:0% +has spectacular orange color like the + + + align:start position:0% +has spectacular orange color like the +orange azaleas and cobalt 3 is like the + + align:start position:0% +orange azaleas and cobalt 3 is like the + + + align:start position:0% +orange azaleas and cobalt 3 is like the +pink azaleas and so they're really + + align:start position:0% +pink azaleas and so they're really + + + align:start position:0% +pink azaleas and so they're really +dramatically different this is why I say + + align:start position:0% +dramatically different this is why I say + + + align:start position:0% +dramatically different this is why I say +this is nature's most beautiful + + align:start position:0% +this is nature's most beautiful + + + align:start position:0% +this is nature's most beautiful +cofactors okay so what I want to do now + + align:start position:0% +cofactors okay so what I want to do now + + + align:start position:0% +cofactors okay so what I want to do now +is briefly talk about mechanism and I'm + + align:start position:0% +is briefly talk about mechanism and I'm + + + align:start position:0% +is briefly talk about mechanism and I'm +going to suppose mostly talk about + + align:start position:0% +going to suppose mostly talk about + + + align:start position:0% +going to suppose mostly talk about +mechanism of the cobalt 2 state and how + + align:start position:0% +mechanism of the cobalt 2 state and how + + + align:start position:0% +mechanism of the cobalt 2 state and how +adenosylcobalamin works since that's the + + align:start position:0% +adenosylcobalamin works since that's the + + + align:start position:0% +adenosylcobalamin works since that's the +one that's most complicated so what I'm + + align:start position:0% +one that's most complicated so what I'm + + + align:start position:0% +one that's most complicated so what I'm +drawing here is if we look at the + + align:start position:0% +drawing here is if we look at the + + + align:start position:0% +drawing here is if we look at the +structure + + align:start position:0% +structure + + + align:start position:0% +structure +if we look at the structure of + + align:start position:0% +if we look at the structure of + + + align:start position:0% +if we look at the structure of +adenosylcobalamin + + align:start position:0% +adenosylcobalamin + + + align:start position:0% +adenosylcobalamin +you see you have a cobalt with four + + align:start position:0% +you see you have a cobalt with four + + + align:start position:0% +you see you have a cobalt with four +nitrogens these are the four nitrogen's + + align:start position:0% +nitrogens these are the four nitrogen's + + + align:start position:0% +nitrogens these are the four nitrogen's +and these are the two axial ligands so + + align:start position:0% +and these are the two axial ligands so + + + align:start position:0% +and these are the two axial ligands so +this is abbreviated I'm going to be + + align:start position:0% +this is abbreviated I'm going to be + + + align:start position:0% +this is abbreviated I'm going to be +using in all the subsequent chemical + + align:start position:0% +using in all the subsequent chemical + + + align:start position:0% +using in all the subsequent chemical +descriptions of what I'm talking about + + align:start position:0% +descriptions of what I'm talking about + + + align:start position:0% +descriptions of what I'm talking about +okay so I'm not going to draw this + + align:start position:0% +okay so I'm not going to draw this + + + align:start position:0% +okay so I'm not going to draw this +structure I would over and over again + + align:start position:0% +structure I would over and over again + + + align:start position:0% +structure I would over and over again +okay so here's our adenosylcobalamin + + align:start position:0% +okay so here's our adenosylcobalamin + + + align:start position:0% +okay so here's our adenosylcobalamin +that we just talked about and there's + + align:start position:0% +that we just talked about and there's + + + align:start position:0% +that we just talked about and there's +DMB is the dimethyl benzyl midazolam and + + align:start position:0% +DMB is the dimethyl benzyl midazolam and + + + align:start position:0% +DMB is the dimethyl benzyl midazolam and +and then you have the 5-prime + + align:start position:0% +and then you have the 5-prime + + + align:start position:0% +and then you have the 5-prime +deoxyadenosine and the top face which is + + align:start position:0% +deoxyadenosine and the top face which is + + + align:start position:0% +deoxyadenosine and the top face which is +where all the chemistry is going to + + align:start position:0% +where all the chemistry is going to + + + align:start position:0% +where all the chemistry is going to +happen so the business end of the + + align:start position:0% +happen so the business end of the + + + align:start position:0% +happen so the business end of the +molecule is going to be this part of the + + align:start position:0% +molecule is going to be this part of the + + + align:start position:0% +molecule is going to be this part of the +molecule and the key to everything is + + align:start position:0% +molecule and the key to everything is + + + align:start position:0% +molecule and the key to everything is +this carbon cobalt bond now what's + + align:start position:0% +this carbon cobalt bond now what's + + + align:start position:0% +this carbon cobalt bond now what's +unusual about a carbon cobalt bond it's + + align:start position:0% +unusual about a carbon cobalt bond it's + + + align:start position:0% +unusual about a carbon cobalt bond it's +very weak if you if you go to 240 + + align:start position:0% +very weak if you if you go to 240 + + + align:start position:0% +very weak if you if you go to 240 +degrees the bond breaks most things you + + align:start position:0% +degrees the bond breaks most things you + + + align:start position:0% +degrees the bond breaks most things you +can go to hundreds of degrees and the + + align:start position:0% +can go to hundreds of degrees and the + + + align:start position:0% +can go to hundreds of degrees and the +bond is stable so it's thermally labile + + align:start position:0% +bond is stable so it's thermally labile + + + align:start position:0% +bond is stable so it's thermally labile +and then the other thing that's unique + + align:start position:0% +and then the other thing that's unique + + + align:start position:0% +and then the other thing that's unique +about this cofactor is that it's + + align:start position:0% +about this cofactor is that it's + + + align:start position:0% +about this cofactor is that it's +light-sensitive so if you put + + align:start position:0% +light-sensitive so if you put + + + align:start position:0% +light-sensitive so if you put +adenosylcobalamin out on the benchtop + + align:start position:0% +adenosylcobalamin out on the benchtop + + + align:start position:0% +adenosylcobalamin out on the benchtop +here within two minutes the whole thing + + align:start position:0% +here within two minutes the whole thing + + + align:start position:0% +here within two minutes the whole thing +would be destroyed because you would + + align:start position:0% +would be destroyed because you would + + + align:start position:0% +would be destroyed because you would +break this carbon cobalt bond okay and + + align:start position:0% +break this carbon cobalt bond okay and + + + align:start position:0% +break this carbon cobalt bond okay and +that's the key to the chemistry of how + + align:start position:0% +that's the key to the chemistry of how + + + align:start position:0% +that's the key to the chemistry of how +this cofactor works okay so I'm gonna + + align:start position:0% +this cofactor works okay so I'm gonna + + + align:start position:0% +this cofactor works okay so I'm gonna +give you a generic mechanism and then + + align:start position:0% +give you a generic mechanism and then + + + align:start position:0% +give you a generic mechanism and then +I'm gonna focus on the mechanism of + + align:start position:0% +I'm gonna focus on the mechanism of + + + align:start position:0% +I'm gonna focus on the mechanism of +methyl Melanie okay a mutase which you + + align:start position:0% +methyl Melanie okay a mutase which you + + + align:start position:0% +methyl Melanie okay a mutase which you +find in human metabolism um before I get + + align:start position:0% +find in human metabolism um before I get + + + align:start position:0% +find in human metabolism um before I get +started let me just show you what the + + align:start position:0% +started let me just show you what the + + + align:start position:0% +started let me just show you what the +reaction is and show you why it's + + align:start position:0% +reaction is and show you why it's + + + align:start position:0% +reaction is and show you why it's +unusual and then we'll go back to the + + align:start position:0% +unusual and then we'll go back to the + + + align:start position:0% +unusual and then we'll go back to the +actual mechanism okay so what does + + align:start position:0% +actual mechanism okay so what does + + + align:start position:0% +actual mechanism okay so what does +methyl Melanie OCO a mutase do again it + + align:start position:0% +methyl Melanie OCO a mutase do again it + + + align:start position:0% +methyl Melanie OCO a mutase do again it +plays a central role in odd chain fatty + + align:start position:0% +plays a central role in odd chain fatty + + + align:start position:0% +plays a central role in odd chain fatty +acid metabolism okay so this is Kawai + + align:start position:0% +acid metabolism okay so this is Kawai + + + align:start position:0% +acid metabolism okay so this is Kawai +you need to go back and look at your + + align:start position:0% +you need to go back and look at your + + + align:start position:0% +you need to go back and look at your +lexicon if you can't remember the + + align:start position:0% +lexicon if you can't remember the + + + align:start position:0% +lexicon if you can't remember the +structure of Kawai but just remember + + align:start position:0% +structure of Kawai but just remember + + + align:start position:0% +structure of Kawai but just remember +it's a thio Wester that's all you need + + align:start position:0% +it's a thio Wester that's all you need + + + align:start position:0% +it's a thio Wester that's all you need +to know okay so this is the substrate + + align:start position:0% +to know okay so this is the substrate + + + align:start position:0% +to know okay so this is the substrate +and this is called methyl + + align:start position:0% +and this is called methyl + + + align:start position:0% +and this is called methyl +one'll go away okay so + + align:start position:0% +one'll go away okay so + + + align:start position:0% +one'll go away okay so +adenosylcobalamin catalyzes + + align:start position:0% +adenosylcobalamin catalyzes + + + align:start position:0% +adenosylcobalamin catalyzes +rearrangements and this reaction has + + align:start position:0% +rearrangements and this reaction has + + + align:start position:0% +rearrangements and this reaction has +fascinated chemists for 30 years because + + align:start position:0% +fascinated chemists for 30 years because + + + align:start position:0% +fascinated chemists for 30 years because +it was a no chemical precedent just like + + align:start position:0% +it was a no chemical precedent just like + + + align:start position:0% +it was a no chemical precedent just like +there was no chemical precedent for + + align:start position:0% +there was no chemical precedent for + + + align:start position:0% +there was no chemical precedent for +carbon cobalt bonds when biochemists + + align:start position:0% +carbon cobalt bonds when biochemists + + + align:start position:0% +carbon cobalt bonds when biochemists +discovered this there was no precedent + + align:start position:0% +discovered this there was no precedent + + + align:start position:0% +discovered this there was no precedent +for the reaction I'm going to show you + + align:start position:0% +for the reaction I'm going to show you + + + align:start position:0% +for the reaction I'm going to show you +so what is the reaction it's a + + align:start position:0% +so what is the reaction it's a + + + align:start position:0% +so what is the reaction it's a +rearrangement and it's rearrangement + + align:start position:0% +rearrangement and it's rearrangement + + + align:start position:0% +rearrangement and it's rearrangement +because this hydrogen moves from this + + align:start position:0% +because this hydrogen moves from this + + + align:start position:0% +because this hydrogen moves from this +carbon to this carbon and this whole + + align:start position:0% +carbon to this carbon and this whole + + + align:start position:0% +carbon to this carbon and this whole +group the SIA West earth moves from this + + align:start position:0% +group the SIA West earth moves from this + + + align:start position:0% +group the SIA West earth moves from this +carbon to this carbon so that's the + + align:start position:0% +carbon to this carbon so that's the + + + align:start position:0% +carbon to this carbon so that's the +actual reaction it's reversible and so + + align:start position:0% +actual reaction it's reversible and so + + + align:start position:0% +actual reaction it's reversible and so +what you do is you generate + + align:start position:0% + + + + align:start position:0% + +succinylcholine is moved over here and + + align:start position:0% +succinylcholine is moved over here and + + + align:start position:0% +succinylcholine is moved over here and +this is succinylcholine and we haven't + + align:start position:0% +this is succinylcholine and we haven't + + + align:start position:0% +this is succinylcholine and we haven't +talked about it yet but succinylcholine + + align:start position:0% +talked about it yet but succinylcholine + + + align:start position:0% +talked about it yet but succinylcholine +Tirol metabolism in the TCA cycle okay + + align:start position:0% +Tirol metabolism in the TCA cycle okay + + + align:start position:0% +Tirol metabolism in the TCA cycle okay +so the question that we want to focus on + + align:start position:0% +so the question that we want to focus on + + + align:start position:0% +so the question that we want to focus on +now is how do you catalyze this weird + + align:start position:0% +now is how do you catalyze this weird + + + align:start position:0% +now is how do you catalyze this weird +rearrangement what is this cofactor this + + align:start position:0% +rearrangement what is this cofactor this + + + align:start position:0% +rearrangement what is this cofactor this +big huge molecule with this carbon weak + + align:start position:0% +big huge molecule with this carbon weak + + + align:start position:0% +big huge molecule with this carbon weak +carbon cobalt by not what does it do + + align:start position:0% +carbon cobalt by not what does it do + + + align:start position:0% +carbon cobalt by not what does it do +okay so I'm going to come back to this + + align:start position:0% +okay so I'm going to come back to this + + + align:start position:0% +okay so I'm going to come back to this +in a minute but this let me show you + + align:start position:0% +in a minute but this let me show you + + + align:start position:0% +in a minute but this let me show you +what it does okay so this is a generic + + align:start position:0% +what it does okay so this is a generic + + + align:start position:0% +what it does okay so this is a generic +mechanism because while I said there's + + align:start position:0% +mechanism because while I said there's + + + align:start position:0% +mechanism because while I said there's +only one enzyme in humans that uses that + + align:start position:0% +only one enzyme in humans that uses that + + + align:start position:0% +only one enzyme in humans that uses that +Denis of CO Baumann if you move in to + + align:start position:0% +Denis of CO Baumann if you move in to + + + align:start position:0% +Denis of CO Baumann if you move in to +fungi or you move into our key or + + align:start position:0% +fungi or you move into our key or + + + align:start position:0% +fungi or you move into our key or +bacteria you find there are many b12 + + align:start position:0% +bacteria you find there are many b12 + + + align:start position:0% +bacteria you find there are many b12 +dependent reactions that also do + + align:start position:0% +dependent reactions that also do + + + align:start position:0% +dependent reactions that also do +rearrangements but different kinds of + + align:start position:0% +rearrangements but different kinds of + + + align:start position:0% +rearrangements but different kinds of +rearrangements okay so what's the + + align:start position:0% +rearrangements okay so what's the + + + align:start position:0% +rearrangements okay so what's the +generic mechanism okay so the generic + + align:start position:0% +generic mechanism okay so the generic + + + align:start position:0% +generic mechanism okay so the generic +mechanism is the following so here we + + align:start position:0% +mechanism is the following so here we + + + align:start position:0% +mechanism is the following so here we +have our adenosylcobalamin here's our + + align:start position:0% +have our adenosylcobalamin here's our + + + align:start position:0% +have our adenosylcobalamin here's our +substrate okay and the idea is and this + + align:start position:0% +substrate okay and the idea is and this + + + align:start position:0% +substrate okay and the idea is and this +is we need to move the hydrogen from + + align:start position:0% +is we need to move the hydrogen from + + + align:start position:0% +is we need to move the hydrogen from +here to here okay + + align:start position:0% +here to here okay + + + align:start position:0% +here to here okay +does it just jump through space and the + + align:start position:0% +does it just jump through space and the + + + align:start position:0% +does it just jump through space and the +answer is no the cofactor + + align:start position:0% +answer is no the cofactor + + + align:start position:0% +answer is no the cofactor +adenosylcobalamin is going to + + align:start position:0% +adenosylcobalamin is going to + + + align:start position:0% +adenosylcobalamin is going to +the hydrogen and then it's gonna + + align:start position:0% +the hydrogen and then it's gonna + + + align:start position:0% +the hydrogen and then it's gonna +transfer it you're going to generate a + + align:start position:0% +transfer it you're going to generate a + + + align:start position:0% +transfer it you're going to generate a +reactive species and then it's gonna + + align:start position:0% +reactive species and then it's gonna + + + align:start position:0% +reactive species and then it's gonna +transfer it back to form a new product + + align:start position:0% +transfer it back to form a new product + + + align:start position:0% +transfer it back to form a new product +so the cofactor and this took people a + + align:start position:0% +so the cofactor and this took people a + + + align:start position:0% +so the cofactor and this took people a +long time to figure out because it was + + align:start position:0% +long time to figure out because it was + + + align:start position:0% +long time to figure out because it was +no chemical precedent for this is + + align:start position:0% +no chemical precedent for this is + + + align:start position:0% +no chemical precedent for this is +mediating the hydrogen transfer so + + align:start position:0% +mediating the hydrogen transfer so + + + align:start position:0% +mediating the hydrogen transfer so +that's what I'm going to show you how + + align:start position:0% +that's what I'm going to show you how + + + align:start position:0% +that's what I'm going to show you how +that actually works so here what happens + + align:start position:0% +that actually works so here what happens + + + align:start position:0% +that actually works so here what happens +is the coal key to the chemistry of + + align:start position:0% +is the coal key to the chemistry of + + + align:start position:0% +is the coal key to the chemistry of +adenosylcobalamin which again is is most + + align:start position:0% +adenosylcobalamin which again is is most + + + align:start position:0% +adenosylcobalamin which again is is most +of you haven't seen something like this + + align:start position:0% +of you haven't seen something like this + + + align:start position:0% +of you haven't seen something like this +before because of the you haven't seen + + align:start position:0% +before because of the you haven't seen + + + align:start position:0% +before because of the you haven't seen +something like this before because + + align:start position:0% +something like this before because + + + align:start position:0% +something like this before because +you're not exposed to radical chemistry + + align:start position:0% +you're not exposed to radical chemistry + + + align:start position:0% +you're not exposed to radical chemistry +is that you have hemolysis of the carbon + + align:start position:0% +is that you have hemolysis of the carbon + + + align:start position:0% +is that you have hemolysis of the carbon +cobalt bond so what does that mean it + + align:start position:0% +cobalt bond so what does that mean it + + + align:start position:0% +cobalt bond so what does that mean it +means one electron goes to the axial + + align:start position:0% +means one electron goes to the axial + + + align:start position:0% +means one electron goes to the axial +ligand and one electron goes to the + + align:start position:0% +ligand and one electron goes to the + + + align:start position:0% +ligand and one electron goes to the +Cobalt so the cobalt 3 is reduced from + + align:start position:0% +Cobalt so the cobalt 3 is reduced from + + + align:start position:0% +Cobalt so the cobalt 3 is reduced from +cobalt 3 to cobalt 2 and what you're + + align:start position:0% +cobalt 3 to cobalt 2 and what you're + + + align:start position:0% +cobalt 3 to cobalt 2 and what you're +left with is this radical species of + + align:start position:0% +left with is this radical species of + + + align:start position:0% +left with is this radical species of +five prime deoxy adenosyl radical okay + + align:start position:0% +five prime deoxy adenosyl radical okay + + + align:start position:0% +five prime deoxy adenosyl radical okay +so this is the reactive species because + + align:start position:0% +so this is the reactive species because + + + align:start position:0% +so this is the reactive species because +what you're doing and these in these + + align:start position:0% +what you're doing and these in these + + + align:start position:0% +what you're doing and these in these +transformations is pulling off an + + align:start position:0% +transformations is pulling off an + + + align:start position:0% +transformations is pulling off an +amazingly non acidic hydrogen and normal + + align:start position:0% +amazingly non acidic hydrogen and normal + + + align:start position:0% +amazingly non acidic hydrogen and normal +amino acid side chains cannot do that + + align:start position:0% +amino acid side chains cannot do that + + + align:start position:0% +amino acid side chains cannot do that +kind of chemistry you have to go to + + align:start position:0% +kind of chemistry you have to go to + + + align:start position:0% +kind of chemistry you have to go to +these reactive radical species to be + + align:start position:0% +these reactive radical species to be + + + align:start position:0% +these reactive radical species to be +able to do this + + align:start position:0% +able to do this + + + align:start position:0% +able to do this +tough chemistry so here we've generated + + align:start position:0% +tough chemistry so here we've generated + + + align:start position:0% +tough chemistry so here we've generated +a radical species it is sitting right + + align:start position:0% +a radical species it is sitting right + + + align:start position:0% +a radical species it is sitting right +next to the substrate in the active site + + align:start position:0% +next to the substrate in the active site + + + align:start position:0% +next to the substrate in the active site +of the enzyme and so what does it do it + + align:start position:0% +of the enzyme and so what does it do it + + + align:start position:0% +of the enzyme and so what does it do it +removes a hydrogen atom a hydrogen with + + align:start position:0% +removes a hydrogen atom a hydrogen with + + + align:start position:0% +removes a hydrogen atom a hydrogen with +one electron okay and so again this is + + align:start position:0% +one electron okay and so again this is + + + align:start position:0% +one electron okay and so again this is +free radical chemistry that most of you + + align:start position:0% +free radical chemistry that most of you + + + align:start position:0% +free radical chemistry that most of you +don't think about that much but what you + + align:start position:0% +don't think about that much but what you + + + align:start position:0% +don't think about that much but what you +do is the hydrogen from the substrate is + + align:start position:0% +do is the hydrogen from the substrate is + + + align:start position:0% +do is the hydrogen from the substrate is +now transferred to this axial ligand + + align:start position:0% +now transferred to this axial ligand + + + align:start position:0% +now transferred to this axial ligand +that stays stuck in the active site so + + align:start position:0% +that stays stuck in the active site so + + + align:start position:0% +that stays stuck in the active site so +we've seen this guy move over here and + + align:start position:0% +we've seen this guy move over here and + + + align:start position:0% +we've seen this guy move over here and +now what you've done is transferred one + + align:start position:0% +now what you've done is transferred one + + + align:start position:0% +now what you've done is transferred one +radical from the cofactor into a second + + align:start position:0% +radical from the cofactor into a second + + + align:start position:0% +radical from the cofactor into a second +radical that substrate okay so that's + + align:start position:0% +radical that substrate okay so that's + + + align:start position:0% +radical that substrate okay so that's +the key now it's carrying this hydrogen + + align:start position:0% +the key now it's carrying this hydrogen + + + align:start position:0% +the key now it's carrying this hydrogen +and + + align:start position:0% +and + + + align:start position:0% +and +eventually it wants to put the hydrogen + + align:start position:0% +eventually it wants to put the hydrogen + + + align:start position:0% +eventually it wants to put the hydrogen +back on to form the product okay that's + + align:start position:0% +back on to form the product okay that's + + + align:start position:0% +back on to form the product okay that's +part of the rearrangement reaction so + + align:start position:0% +part of the rearrangement reaction so + + + align:start position:0% +part of the rearrangement reaction so +what happens now is and this looks like + + align:start position:0% +what happens now is and this looks like + + + align:start position:0% +what happens now is and this looks like +magic + + align:start position:0% +magic + + + align:start position:0% +magic +I'm just showing that a substrate + + align:start position:0% +I'm just showing that a substrate + + + align:start position:0% +I'm just showing that a substrate +radical goes to product radical and I + + align:start position:0% +radical goes to product radical and I + + + align:start position:0% +radical goes to product radical and I +will show you how this works in the case + + align:start position:0% +will show you how this works in the case + + + align:start position:0% +will show you how this works in the case +of methyl Melanie lock away mute is in a + + align:start position:0% +of methyl Melanie lock away mute is in a + + + align:start position:0% +of methyl Melanie lock away mute is in a +minute okay so there's some kind of + + align:start position:0% +minute okay so there's some kind of + + + align:start position:0% +minute okay so there's some kind of +rearrangement remember we had two things + + align:start position:0% +rearrangement remember we had two things + + + align:start position:0% +rearrangement remember we had two things +rearranging the hydrogen but we also had + + align:start position:0% +rearranging the hydrogen but we also had + + + align:start position:0% +rearranging the hydrogen but we also had +a second a thioester rearranging so we + + align:start position:0% +a second a thioester rearranging so we + + + align:start position:0% +a second a thioester rearranging so we +have a rearrangement reaction and this + + align:start position:0% +have a rearrangement reaction and this + + + align:start position:0% +have a rearrangement reaction and this +is reversible and in the reaction I'm + + align:start position:0% +is reversible and in the reaction I'm + + + align:start position:0% +is reversible and in the reaction I'm +going to be talking about today and so + + align:start position:0% +going to be talking about today and so + + + align:start position:0% +going to be talking about today and so +this is the same as this structurally + + align:start position:0% +this is the same as this structurally + + + align:start position:0% +this is the same as this structurally +these are the same I've just written out + + align:start position:0% +these are the same I've just written out + + + align:start position:0% +these are the same I've just written out +the methyl group and so we have a + + align:start position:0% +the methyl group and so we have a + + + align:start position:0% +the methyl group and so we have a +substrate radical converting into a + + align:start position:0% +substrate radical converting into a + + + align:start position:0% +substrate radical converting into a +product radical okay and now what we + + align:start position:0% +product radical okay and now what we + + + align:start position:0% +product radical okay and now what we +want to do is generate the product and + + align:start position:0% +want to do is generate the product and + + + align:start position:0% +want to do is generate the product and +so the hydrogen from this carrier your + + align:start position:0% +so the hydrogen from this carrier your + + + align:start position:0% +so the hydrogen from this carrier your +axial again is now going to be + + align:start position:0% +axial again is now going to be + + + align:start position:0% +axial again is now going to be +transferred by hydrogen atom transfer + + align:start position:0% +transferred by hydrogen atom transfer + + + align:start position:0% +transferred by hydrogen atom transfer +back to P dot to form the product so + + align:start position:0% +back to P dot to form the product so + + + align:start position:0% +back to P dot to form the product so +again it's one electron chemistry and + + align:start position:0% +again it's one electron chemistry and + + + align:start position:0% +again it's one electron chemistry and +doing one electron chemistry the + + align:start position:0% +doing one electron chemistry the + + + align:start position:0% +doing one electron chemistry the +hydrogen is transferred back to P and + + align:start position:0% +hydrogen is transferred back to P and + + + align:start position:0% +hydrogen is transferred back to P and +then what do you do you lose one radical + + align:start position:0% +then what do you do you lose one radical + + + align:start position:0% +then what do you do you lose one radical +and you generate another radical you + + align:start position:0% +and you generate another radical you + + + align:start position:0% +and you generate another radical you +regenerate the radical we started with + + align:start position:0% +regenerate the radical we started with + + + align:start position:0% +regenerate the radical we started with +the five prime deoxyadenosine radical on + + align:start position:0% +the five prime deoxyadenosine radical on + + + align:start position:0% +the five prime deoxyadenosine radical on +the axial again now I have written here + + align:start position:0% +the axial again now I have written here + + + align:start position:0% +the axial again now I have written here +hydrogen in black and in red why is that + + align:start position:0% +hydrogen in black and in red why is that + + + align:start position:0% +hydrogen in black and in red why is that +true because here's a methyl group and + + align:start position:0% +true because here's a methyl group and + + + align:start position:0% +true because here's a methyl group and +if you have free complete freedom of + + align:start position:0% +if you have free complete freedom of + + + align:start position:0% +if you have free complete freedom of +rotation around that carbon-carbon bond + + align:start position:0% +rotation around that carbon-carbon bond + + + align:start position:0% +rotation around that carbon-carbon bond +you can pull off either the methyl + + align:start position:0% +you can pull off either the methyl + + + align:start position:0% +you can pull off either the methyl +hydrogen's become equivalent so it can + + align:start position:0% +hydrogen's become equivalent so it can + + + align:start position:0% +hydrogen's become equivalent so it can +pull off a hydrogen red or a hydrogen + + align:start position:0% +pull off a hydrogen red or a hydrogen + + + align:start position:0% +pull off a hydrogen red or a hydrogen +black okay can't distinguish in the + + align:start position:0% +black okay can't distinguish in the + + + align:start position:0% +black okay can't distinguish in the +active site of the enzyme so what you + + align:start position:0% +active site of the enzyme so what you + + + align:start position:0% +active site of the enzyme so what you +now generate is the same thing we + + align:start position:0% +now generate is the same thing we + + + align:start position:0% +now generate is the same thing we +started with but except we have a + + align:start position:0% +started with but except we have a + + + align:start position:0% +started with but except we have a +product but we have five prime + + align:start position:0% +product but we have five prime + + + align:start position:0% +product but we have five prime +deoxyadenosine cobalt do here we have + + align:start position:0% +deoxyadenosine cobalt do here we have + + + align:start position:0% +deoxyadenosine cobalt do here we have +five prime deoxyadenosine radical cobalt + + align:start position:0% +five prime deoxyadenosine radical cobalt + + + align:start position:0% +five prime deoxyadenosine radical cobalt +two and what you do is you reform the + + align:start position:0% +two and what you do is you reform the + + + align:start position:0% +two and what you do is you reform the +carbon cobalt bond at the end of every + + align:start position:0% +carbon cobalt bond at the end of every + + + align:start position:0% +carbon cobalt bond at the end of every +turnover and now you're ready to start + + align:start position:0% +turnover and now you're ready to start + + + align:start position:0% +turnover and now you're ready to start +all over again + + align:start position:0% +all over again + + + align:start position:0% +all over again +so that's the reaction this five prime + + align:start position:0% +so that's the reaction this five prime + + + align:start position:0% +so that's the reaction this five prime +deoxyadenosine + + align:start position:0% + + + + align:start position:0% + +alig in this axial ligand sitting over + + align:start position:0% +alig in this axial ligand sitting over + + + align:start position:0% +alig in this axial ligand sitting over +here acts as a hydrogen atom + + align:start position:0% +here acts as a hydrogen atom + + + align:start position:0% +here acts as a hydrogen atom +transferring agent to remove a hydrogen + + align:start position:0% +transferring agent to remove a hydrogen + + + align:start position:0% +transferring agent to remove a hydrogen +from the substrate and to transfer it + + align:start position:0% +from the substrate and to transfer it + + + align:start position:0% +from the substrate and to transfer it +back to the product okay I'm going to + + align:start position:0% +back to the product okay I'm going to + + + align:start position:0% +back to the product okay I'm going to +show you how this works now in the case + + align:start position:0% +show you how this works now in the case + + + align:start position:0% +show you how this works now in the case +of methyl Melanie Alcoa mutase so here's + + align:start position:0% +of methyl Melanie Alcoa mutase so here's + + + align:start position:0% +of methyl Melanie Alcoa mutase so here's +our methyl Melanie Ocoee and we're going + + align:start position:0% +our methyl Melanie Ocoee and we're going + + + align:start position:0% +our methyl Melanie Ocoee and we're going +to be converted into succinate Ocoee so + + align:start position:0% +to be converted into succinate Ocoee so + + + align:start position:0% +to be converted into succinate Ocoee so +this again is migrating and this guy is + + align:start position:0% +this again is migrating and this guy is + + + align:start position:0% +this again is migrating and this guy is +migrating there that's the goal and so + + align:start position:0% +migrating there that's the goal and so + + + align:start position:0% +migrating there that's the goal and so +what happens here is you cleave the + + align:start position:0% +what happens here is you cleave the + + + align:start position:0% +what happens here is you cleave the +carbon cobalt bond to form cobalt 2 & 5 + + align:start position:0% +carbon cobalt bond to form cobalt 2 & 5 + + + align:start position:0% +carbon cobalt bond to form cobalt 2 & 5 +Prime deoxy adenosyl radical and now + + align:start position:0% +Prime deoxy adenosyl radical and now + + + align:start position:0% +Prime deoxy adenosyl radical and now +this five prime deoxyadenosine + + align:start position:0% +this five prime deoxyadenosine + + + align:start position:0% +this five prime deoxyadenosine +can remove a hydrogen atom from the + + align:start position:0% +can remove a hydrogen atom from the + + + align:start position:0% +can remove a hydrogen atom from the +substrate so it leaves you with another + + align:start position:0% +substrate so it leaves you with another + + + align:start position:0% +substrate so it leaves you with another +radical this radical goes away you + + align:start position:0% +radical this radical goes away you + + + align:start position:0% +radical this radical goes away you +generate another radical and now this + + align:start position:0% +generate another radical and now this + + + align:start position:0% +generate another radical and now this +hydrogen from the substrate is + + align:start position:0% +hydrogen from the substrate is + + + align:start position:0% +hydrogen from the substrate is +transferred to our cofactor so it's the + + align:start position:0% +transferred to our cofactor so it's the + + + align:start position:0% +transferred to our cofactor so it's the +hydrogen transferring agent so now the + + align:start position:0% +hydrogen transferring agent so now the + + + align:start position:0% +hydrogen transferring agent so now the +question is how does this weird + + align:start position:0% +question is how does this weird + + + align:start position:0% +question is how does this weird +rearrangement reaction it how does this + + align:start position:0% +rearrangement reaction it how does this + + + align:start position:0% +rearrangement reaction it how does this +co a migrate from one place to another + + align:start position:0% +co a migrate from one place to another + + + align:start position:0% +co a migrate from one place to another +again there was no chemical precedent + + align:start position:0% +again there was no chemical precedent + + + align:start position:0% +again there was no chemical precedent +and a literature for this and when the + + align:start position:0% +and a literature for this and when the + + + align:start position:0% +and a literature for this and when the +answer is we still don't know the answer + + align:start position:0% +answer is we still don't know the answer + + + align:start position:0% +answer is we still don't know the answer +so there are two mechanistic + + align:start position:0% +so there are two mechanistic + + + align:start position:0% +so there are two mechanistic +possibilities one is that you go through + + align:start position:0% +possibilities one is that you go through + + + align:start position:0% +possibilities one is that you go through +a three membered ring cyclopropane ring + + align:start position:0% +a three membered ring cyclopropane ring + + + align:start position:0% +a three membered ring cyclopropane ring +intermediate so what you can picture + + align:start position:0% +intermediate so what you can picture + + + align:start position:0% +intermediate so what you can picture +happening is that one of the electrons + + align:start position:0% +happening is that one of the electrons + + + align:start position:0% +happening is that one of the electrons +from the carbonyl forms a bond with the + + align:start position:0% +from the carbonyl forms a bond with the + + + align:start position:0% +from the carbonyl forms a bond with the +unpaired electron on this carbon and you + + align:start position:0% +unpaired electron on this carbon and you + + + align:start position:0% +unpaired electron on this carbon and you +generate this cyclopropane intermediate + + align:start position:0% +generate this cyclopropane intermediate + + + align:start position:0% +generate this cyclopropane intermediate +so you've gone from this radical to + + align:start position:0% +so you've gone from this radical to + + + align:start position:0% +so you've gone from this radical to +another radical we haven't lost any + + align:start position:0% +another radical we haven't lost any + + + align:start position:0% +another radical we haven't lost any +radicals but now what we want to do is + + align:start position:0% +radicals but now what we want to do is + + + align:start position:0% +radicals but now what we want to do is +we want this group to migrate so now + + align:start position:0% +we want this group to migrate so now + + + align:start position:0% +we want this group to migrate so now +what happens this intermediate can + + align:start position:0% +what happens this intermediate can + + + align:start position:0% +what happens this intermediate can +collapse it can collapse back to form + + align:start position:0% +collapse it can collapse back to form + + + align:start position:0% +collapse it can collapse back to form +starting material and the 5-prime + + align:start position:0% +starting material and the 5-prime + + + align:start position:0% +starting material and the 5-prime +deoxyadenosine radical or you can break + + align:start position:0% +deoxyadenosine radical or you can break + + + align:start position:0% +deoxyadenosine radical or you can break +this bond in which case you collapse to + + align:start position:0% +this bond in which case you collapse to + + + align:start position:0% +this bond in which case you collapse to +form the direct precursor to the product + + align:start position:0% +form the direct precursor to the product + + + align:start position:0% +form the direct precursor to the product +so it can break down in either direction + + align:start position:0% +so it can break down in either direction + + + align:start position:0% +so it can break down in either direction +and the reaction is reversible and if it + + align:start position:0% +and the reaction is reversible and if it + + + align:start position:0% +and the reaction is reversible and if it +breaks down in this direction you form a + + align:start position:0% +breaks down in this direction you form a + + + align:start position:0% +breaks down in this direction you form a +new router + + align:start position:0% +new router + + + align:start position:0% +new router +this radical is distinct from this + + align:start position:0% +this radical is distinct from this + + + align:start position:0% +this radical is distinct from this +radical and now what happens is that the + + align:start position:0% +radical and now what happens is that the + + + align:start position:0% +radical and now what happens is that the +hydrogen that you removed from your + + align:start position:0% +hydrogen that you removed from your + + + align:start position:0% +hydrogen that you removed from your +starting material can be returned back + + align:start position:0% +starting material can be returned back + + + align:start position:0% +starting material can be returned back +to the product and what you generate + + align:start position:0% +to the product and what you generate + + + align:start position:0% +to the product and what you generate +then is five prime deoxyadenosine + + align:start position:0% +then is five prime deoxyadenosine + + + align:start position:0% +then is five prime deoxyadenosine +radical and cobalt two and now you've + + align:start position:0% +radical and cobalt two and now you've + + + align:start position:0% +radical and cobalt two and now you've +when you transfer the hydrogen back you + + align:start position:0% +when you transfer the hydrogen back you + + + align:start position:0% +when you transfer the hydrogen back you +form your product like I showed you in + + align:start position:0% +form your product like I showed you in + + + align:start position:0% +form your product like I showed you in +the previous slide and now you reform + + align:start position:0% +the previous slide and now you reform + + + align:start position:0% +the previous slide and now you reform +the carbon cobalt bond to form reform + + align:start position:0% +the carbon cobalt bond to form reform + + + align:start position:0% +the carbon cobalt bond to form reform +that active form of the cofactor so + + align:start position:0% +that active form of the cofactor so + + + align:start position:0% +that active form of the cofactor so +alternatively you can make this + + align:start position:0% +alternatively you can make this + + + align:start position:0% +alternatively you can make this +rearrangement happen by another + + align:start position:0% +rearrangement happen by another + + + align:start position:0% +rearrangement happen by another +mechanism which is called a + + align:start position:0% +mechanism which is called a + + + align:start position:0% +mechanism which is called a +fragmentation mechanism and I won't go + + align:start position:0% +fragmentation mechanism and I won't go + + + align:start position:0% +fragmentation mechanism and I won't go +through the details in this but you can + + align:start position:0% +through the details in this but you can + + + align:start position:0% +through the details in this but you can +sit and look at this for those of you + + align:start position:0% +sit and look at this for those of you + + + align:start position:0% +sit and look at this for those of you +are really interested in sophisticated + + align:start position:0% +are really interested in sophisticated + + + align:start position:0% +are really interested in sophisticated +proposals for the chemical mechanisms of + + align:start position:0% +proposals for the chemical mechanisms of + + + align:start position:0% +proposals for the chemical mechanisms of +the rearrangement so adenosylcobalamin + + align:start position:0% +the rearrangement so adenosylcobalamin + + + align:start position:0% +the rearrangement so adenosylcobalamin +chemistry is unprecedented every step in + + align:start position:0% +chemistry is unprecedented every step in + + + align:start position:0% +chemistry is unprecedented every step in +the way every step along the way and + + align:start position:0% +the way every step along the way and + + + align:start position:0% +the way every step along the way and +it's now known to be widely used but not + + align:start position:0% +it's now known to be widely used but not + + + align:start position:0% +it's now known to be widely used but not +so much so in humans but you know really + + align:start position:0% +so much so in humans but you know really + + + align:start position:0% +so much so in humans but you know really +humans are only a small part of the + + align:start position:0% +humans are only a small part of the + + + align:start position:0% +humans are only a small part of the +world we have many many more bacteria in + + align:start position:0% +world we have many many more bacteria in + + + align:start position:0% +world we have many many more bacteria in +our ki then we have humans so this is a + + align:start position:0% +our ki then we have humans so this is a + + + align:start position:0% +our ki then we have humans so this is a +pretty important transformation so + + align:start position:0% +pretty important transformation so + + + align:start position:0% +pretty important transformation so +hopefully now when you see this again it + + align:start position:0% +hopefully now when you see this again it + + + align:start position:0% +hopefully now when you see this again it +won't be completely magic but this is a + + align:start position:0% +won't be completely magic but this is a + + + align:start position:0% +won't be completely magic but this is a +challenging reaction that most of you + + align:start position:0% +challenging reaction that most of you + + + align:start position:0% +challenging reaction that most of you +haven't been exposed to before but + + align:start position:0% +haven't been exposed to before but + + + align:start position:0% +haven't been exposed to before but +hopefully some of you get excited about + + align:start position:0% +hopefully some of you get excited about + + + align:start position:0% +hopefully some of you get excited about +radical mediated transformations I just + + align:start position:0% +radical mediated transformations I just + + + align:start position:0% +radical mediated transformations I just +let me close by saying from + + align:start position:0% +let me close by saying from + + + align:start position:0% +let me close by saying from +bioinformatics studies in the last five + + align:start position:0% +bioinformatics studies in the last five + + + align:start position:0% +bioinformatics studies in the last five +years or so we now know there are over + + align:start position:0% +years or so we now know there are over + + + align:start position:0% +years or so we now know there are over +50,000 reactions that use free radical + + align:start position:0% +50,000 reactions that use free radical + + + align:start position:0% +50,000 reactions that use free radical +chemistry yet we don't talk about + + align:start position:0% +chemistry yet we don't talk about + + + align:start position:0% +chemistry yet we don't talk about +radical chemistry in 507 so hopefully + + align:start position:0% +radical chemistry in 507 so hopefully + + + align:start position:0% +radical chemistry in 507 so hopefully +some of you will get interested enough + + align:start position:0% +some of you will get interested enough + + + align:start position:0% +some of you will get interested enough +in biochemistry to come in and start + + align:start position:0% +in biochemistry to come in and start + + + align:start position:0% +in biochemistry to come in and start +figuring out how all these radical + + align:start position:0% +figuring out how all these radical + + + align:start position:0% +figuring out how all these radical +dependent reactions occur not in primary + + align:start position:0% +dependent reactions occur not in primary + + + align:start position:0% +dependent reactions occur not in primary +metabolism but in many secondary + + align:start position:0% +metabolism but in many secondary + + + align:start position:0% +metabolism but in many secondary +metabolic pathways okay thank you \ No newline at end of file diff --git a/6xaaeop7gJ8.txt b/6xaaeop7gJ8.txt new file mode 100644 index 0000000000000000000000000000000000000000..316f6ab0d6fe9232df9919db06c9bb99403963f0 --- /dev/null +++ b/6xaaeop7gJ8.txt @@ -0,0 +1,1794 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high-quality educational +resources for free. + +To make a donation or view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu. + +PROFESSOR: In the last lecture, +I introduced and + +illustrated the kinds of signals +and systems that we'll + +be dealing with throughout +this course. + +In today's lecture I'd like to +be a little more specific, and + +in particular, talk about some +of the basic signals, both + +continuous-time and +discrete-time that will form + +important building blocks as +the course progresses. + +Let's begin with one signal, the +continuous-time sinusoidal + +signal, which perhaps +you're already + +somewhat familiar with. + +Mathematically, the +continuous-time sinusoidal + +signal is expressed as +I've indicated here. + +There are three parameters, +A, omega_0 and phi. + +The parameter A is referred +to as the amplitude, the + +parameter omega 0 as the +frequency, and the parameter + +phi as the phase. + +And graphically, the +continuous-time sinusoidal + +signal has the form +shown here. + +Now, the sinusoidal signal +has a number of important + +properties that we'll find it +convenient to exploit as the + +course goes along, one of which +is the fact that the + +sinusoidal signal is what is +referred to as periodic. + +What I mean by periodic is that +under an appropriate time + +shift, which I indicate here as +T_0, the signal replicates + +or repeats itself. + +Or said another way, if we shift +the time origin by an + +appropriate amount T_0, the +smallest value T_0 being + +referred to as the period, +then x(t) is + +equal to itself, shifted. + +And we can demonstrate it +mathematically by simply + +substituting into the +mathematical expression for + +the sinusoidal signal t ++ T_0, in place of t. + +When we carry out the expansion +we then have, for + +the argument of the sinusoid, +omega_0 t + omega_0 T_0 + phi. + +Now, one of the things that +we know about sinusoidal + +functions is that if you change +the argument by any + +integer multiple of 2 pi, +then the function + +has the same value. + +And so we can exploit that +here, in particular with + +omega_0 T_0 and integer +multiple of 2 pi. + +Then the right-hand side of this +equation is equal to the + +left-hand side of +the equation. + +So with omega_0 T_0 equal to 2 +pi times an integer, or T_0 + +equal to 2 pi times an +integer divided by + +omega_0, the signal repeats. + +The period is defined as the +smallest value of T_0. + +And so the period is 2 pi +divided by omega_0. + +And going back to +our sinusoidal + +signal, we can see that-- + +and I've indicated here, then, +the period as 2 pi / omega_0. + +And that's the value under +which the signal repeats. + +Now in addition, a useful +property of the sinusoidal + +signal is the fact that a time +shift of a sinusoid is + +equivalent to a phase change. + +And we can demonstrate that +again mathematically, in + +particular if we put the +sinusoidal signal + +under a time shift-- + +I've indicated the time +shift that I'm + +talking about by t_0-- + +and expand this out, then we see +that that is equivalent to + +a change in phase. + +And an important thing to +recognize about this statement + +is that not only is a time +shift generating a phase + +change, but, in fact, if we +inserted a phase change, there + +is always a value of t_0 which +would correspond to an + +equivalent time shift. + +Said another way, if we take +omega_0 t_0 and think of that + +as our change in phase, for any +change in phase, we can + +solve this equation for a time +shift, or conversely for any + +value of time shift, +that represents + +an appropriate phase. + +So a time shift corresponds to +a phase change, and a phase + +change, likewise, corresponds +to time shift. + +And so for example, if we look +at the general sinusoidal + +signal that we saw previously, +in effect, changing the phase + +corresponds to moving +this signal in time + +one way or the other. + +For example, if we look at the +sinusoidal signal with a phase + +equal to 0 that corresponds +to locating the time + +origin at this peak. + +And I've indicated that on +the following graph. + +So here we have illustrated a +sinusoid with 0 phase, or a + +cosine with 0 phase, +corresponding to taking our + +general picture and +shifting it. + +Shifting it appropriately +as I've indicated here. + +This, of course, still has the +property that it's a periodic + +function, since we simply +displaced it in time. + +And by looking at the graph, +what we see is that it has + +another very important property, +a property referred + +to as even. + +And that's a property that we'll +find useful, in general, + +to refer to in relation +to signals. + +A signal is said to be even if, +when we reflect it about + +the origin, it looks +exactly the same. + +So it's symmetric about +the origin. + +And looking at this +sinusoid, that, in + +fact, has that property. + +And mathematically, the +statement that it's even is + +equivalent to the statement that +if we replace the time + +argument by its negative, +the function + +itself doesn't change. + +Now this corresponded to a +phase shift of 0 in our + +original cosine expression. + +If instead, we had chosen a +phase shift of, let's say, + +-pi/2, then instead of a +cosinusoidal signal, what we + +would regenerate is a sinusoid +with the appropriate phase. + +Or, said another way, if we take +our original cosine and + +substitute in for the phase +-pi/2, then of course we have + +this mathematical expression. + +Using just straightforward +trigonometric identities, we + +can express that alternately +as sin(omega_0*t). + +The frequency and amplitude, +of course, haven't changed. + +And that, you can convince +yourself, also is equivalent + +to shifting the cosine by an +amount in time that I've + +indicated here, namely a +quarter of a period. + +So illustrated below is the +graph now, when we have a + +phase of -pi/2 in our cosine, +which is a sinusoidal signal. + +Of course, it's still +periodic. + +It's periodic with a period of +2 pi / omega_0 again, because + +all that we've done by +introducing a phase change is + +introduced the time shift. + +Now, when we look at the +sinusoid in comparison with + +the cosine, namely with this +particular choice of phase, + +this has a different symmetry, +and that symmetry + +is referred to odd. + +What odd symmetry means, +graphically, is that when we + +flip the signal about the time +origin, we also multiply it by + +a minus sign. + +So that's, in effect, +anti-symmetric. + +It's not the mirror image, +but it's the mirror + +image flipped over. + +And we'll find many occasions, +not only to refer to signals + +more general than sinusoidal +signals, as even in some cases + +and odd in other cases. + +And in general, mathematically, +an odd signal + +is one which satisfies the +algebraic expression, x(t). + +When you replace t by its +negative, is equal to -x(-t). + +So replacing the argument by its +negative corresponds to an + +algebraic sign reversal. + +OK. + +So this is the class of +continuous-time sinusoids. + +We'll have a little more +to say about it later. + +But I'd now like to turn to +discrete-time sinusoids. + +What we'll see is that +discrete-time sinusoids are + +very much like continuous-time +ones, but also with some very + +important differences. + +And we want to focus, not only +on the similarities, but also + +on the differences. + +Well, let's begin with the +mathematical expression. + +A discrete-time sinusoidal +signal, mathematically, is as + +I've indicated here, A +cos(omega_0 n + phi). + +And just as in the +continuous-time case, the + +parameter A is what we'll refer +to as the amplitude, + +omega_0 as the frequency, +and phi as the phase. + +And I've illustrated here +several discrete-time + +sinusoidal signals. + +And they kind of look similar. + +In fact, if you track what +you might think of as the + +envelope, it looks very much +like what a continuous-time + +sinusoid might look like. + +But keep in mind that the +independent variable, in this + +case, is an integer variable. + +And so the sequence only takes +on values at integer values of + +the argument. + +And we'll see that has a very +important implication, and + +we'll see that shortly. + +Now, one of the issues that +we addressed in the + +continuous-time case +was periodicity. + +And I want to return to that +shortly, because that is one + +of the areas where there is +an important distinction. + +Let's first, though, examine the +statement similar to the + +one that we examined for +continuous time, namely the + +relationship between a time +shift and a phase change. + +Now, in continuous time, of +course, we saw that a time + +shift corresponds to a phase +change, and vice versa. + +Let's first look at the +relationship between shifting + +time and generating +a change in phase. + +In particular for discrete time, +if I implement a time + +shift that generates +a phase change-- + +and we can see that easily +by simply inserting a + +time shift, n + n_0. + +And if we expand out this +argument, we have omega_0 n + + +omega_0 n_0. + +And so I've done that on the +right-hand side of the + +equation here. + +And the omega_0 n_0, then, +simply corresponds + +to a change in phase. + +So clearly, a shift in time +generates a change in phase. + +And for example, if we take a +particular sinusoidal signal, + +let's say we take the cosine +signal at a particular + +frequency, and with a phase +equal to 0, a sequence that we + +might generate is one that +I've illustrated here. + +So what I'm illustrating +here is the cosine + +signal with 0 phase. + +And it has a particular behavior +to it, which will + +depend somewhat on +the frequency. + +If I now take this same sequence +and shift it so that + +the time origin is shifted a +quarter of a period away, then + +you can convince yourself-- + +and it's straightforward to +work out-- that that time + +shift corresponds to a +phase shift of pi/2. + +So in that case, with the cosine +with a phase of -pi/2, + +that will correspond to the +expression that I have here. + +We could alternately write +that, using again a + +trigonometric identity, +as a sine function. + +And that, I've stated, is +equivalent to a time shift. + +Namely, this shift of pi/2 is +equal to a certain time shift, + +and the time shift for this +particular example is a + +quarter of a period. + +So here, we have the sinusoid. + +Previously we had the cosine. + +The cosine was exactly the same +sequence, but with the + +origin located here. + +And in fact, that's exactly the +way we drew this graph. + +Namely, we just simply took the +same values and changed + +the time origin. + +Now, looking at this sequence, +which is the sinusoidal + +sequence, the phase of -pi/2, +that has a certain symmetry. + +And in fact, what we see is that +it has an odd symmetry, + +just as in the continuous-time +case. + +Namely, if we take that +sequence, flip it about the + +axis, and flip it over in sign, +that we get the same + +sequence back again. + +Whereas with 0 phase +corresponding to the cosine + +that I showed previously, that +has an even symmetry. + +Namely, if I flip it about the +time origin and don't do a + +sign reversal, then the sequence +is maintained. + +So here, we have an odd +symmetry, expressed + +mathematically as +I've indicated. + +Namely, replacing the +independent variable by its + +negative attaches a negative +sign to the whole sequence. + +Whereas in the previous case, +what we have is 0 phase and an + +even symmetry. + +And that's expressed +mathematically as x[n] + += x[-n]. + +Now, one of the things I've +said so far about + +discrete-time sinusoids is that +a time shift corresponds + +to a phase change. + +And we can then ask whether the +reverse statement is also + +true, and we knew that the +reverse statement was true in + +continuous time. + +Specifically, is it true that +a phase change always + +corresponds to a time shift? + +Now, we know that that is +true, namely, that this + +statement works both ways +in continuous time. + +Does it in discrete time? + +Well, the answer, somewhat +interestingly or surprisingly + +until you sit down and think +about it, is no. + +It is not necessarily true in +discrete time that any phase + +change can be interpreted +as a simple time + +shift of the sequence. + +And let me just indicate +what the problem is. + +If we look at the relationship +between the left side and the + +right side of this equation, +expanding this out as we did + +previously, we have that omega_0 +n + omega_0 n_0 must + +correspond to omega_0 n + phi. + +And so omega_0 n_0 +must correspond + +to the phase change. + +Now, what you can see pretty +clearly is that depending on + +the relationship between phi +and omega_0, n_0 may or may + +not come out to be an integer. + +Now, in continuous time, the +amount of time shift did not + +have to be an integer amount. + +In discrete time, when we talk +about a time shift, the amount + +of time shift-- obviously, +because of the nature of + +discrete time signals-- + +must be an integer. + +So the phase changes related +to time shifts must satisfy + +this particular relationship. + +Namely, that omega_0 n_0, where +n_0 is an integer, is + +equal to the change in phase. + +OK. + +Now, that's one distinction +between continuous time and + +discrete time. + +Let's now focus on another +one, namely the issue of + +periodicity. + +And what we'll see is that +again, whereas in continuous + +time, all continuous-time +sinusoids are periodic, in the + +discrete-time case that is +not necessarily true. + +To explore that a little more +carefully, let's look at the + +expression, again, for a general +sinusoidal signal with + +an arbitrary amplitude, +frequency, and phase. + +And for this to be periodic, +what we require is that there + +be some value, N, under which, +when we shift the sequence by + +that amount, we get the same +sequence back again. + +And the smallest-value +N is what we've + +defined as the period. + +Now, when we try that on a +sinusoid, we of course + +substitute in for n, n + N. +And when we expand out the + +argument here, we'll get the +argument that I have on the + +right-hand side. + +And in order for this to repeat, +in other words, in + +order for us to discard this +term, omega_0 N, where N is + +the period, must be an integer +multiple of 2 pi. + +And in that case, it's periodic +as long as omega_0 N, + +N being the period, is 2 +pi times an integer. + +Just simply dividing this out, +we have N, the period, is 2 pi + +m / omega_0. + +Well, you could say, OK +what's the big deal? + +Whatever N happens to come out +to be when we do that little + +bit of algebra, that's +the period. + +But in fact, N, or 2 pi m / +omega_0, may not ever come out + +to be an integer. + +Or it may not come out +to be the one that + +you thought it might. + +For example, let's look at some + +particular sinusoidal signals. + +Let's see. + +We have the first one +here, which is a + +sinusoid, as I've shown. + +And it has a frequency, what +I've referred to as the + +frequency, omega_0 += 2 pi / 12. + +And what we'd like to look at +is 2 pi / omega_0, then find + +an integer to multiply +that by in order + +to get another integer. + +Let's just try that here. + +If we look at 2 pi / omega_0, 2 +pi / omega_0, for this case, + +is equal to 12. + +Well, that's fine. + +12 is an integer. + +So what that says is that this +sinusoidal signal is periodic. + +And in fact, it's periodic +with a period of 12. + +Let's look at the next one. + +The next one, we would have +2 pi / omega_0 again. + +And that's equal to 31/4. + +So what that says is that +the period is 31/4. + +But wait a minute. + +31/4 isn't an integer. + +We have to multiply +that by an integer + +to get another integer. + +Well, we'd multiply that by 4, +so (2 pi / omega_0) times 4 is + +31, 31 is an integer. + +And so what that says is this is +periodic, not with a period + +of 2 pi / omega_0, but with a +period of (2 pi / omega_0) + +times 4, namely with +a period of 31. + +Finally, let's take the example +where omega_0 is equal + +to 1/6, as I've shown here. + +That actually looks, if you +track it with your eye, like + +it's periodic. + +2 pi / omega_0, in that case, +is equal to 12 pi. + +Well, what integer can I +multiply 12 pi by and get + +another integer? + +The answer is none, because pi +is an irrational number. + +So in fact, what that says is +that if you look at this + +sinusoidal signal, it's not +periodic at all, even though + +you might fool yourself into +thinking it is simply because + +the envelope looks periodic. + +Namely, the continuous-time +equivalent of this is + +periodic, the discrete-time +sequence is not. + +OK. + +Well, we've seen, then, some +important distinctions between + +continuous-time sinusoidal +signals and discrete-time + +sinusoidal signals. + +The first one is the fact that +in the continuous-time case, a + +time shift and phase change +are always equivalent. + +Whereas in the discrete-time +case, in effect, it works one + +way but not the other way. + +We've also seen that for a +continuous-time signal, the + +continuous-time signal is always +periodic, whereas the + +discrete-time signal +is not necessarily. + +In particular, for the +continuous-time case, if we + +have a general expression for +the sinusoidal signal that + +I've indicated here, +that's periodic for + +any choice of omega_0. + +Whereas in the discrete-time +case, it's periodic only if 2 + +pi / omega_0 can be multiplied +by an integer + +to get another integer. + +Now, another important and, +as it turns out, useful + +distinction between the +continuous-time and + +discrete-time case is the fact +that in the discrete-time + +case, as we vary what I've +called the frequency omega_0, + +we only see distinct +signals as omega_0 + +varies over a 2 pi interval. + +And if we let omega_0 vary +outside the range of, let's + +say, -pi to pi, or 0 to 2 pi, +we'll see the same sequences + +all over again, even though at +first glance, the mathematical + +expression might +look different. + +So in the discrete-time case, +this class of signals is + +identical for values of omega_0 +separated by 2 pi, + +whereas in the continuous-time +case, that is not true. + +In particular, if I consider +these sinusoidal + +continuous-time signals, as I +vary omega_0, what will happen + +is that I will always see +different sinusoidal signals. + +Namely, these won't be equal. + +And in effect, we can justify +that statement algebraically. + +And I won't take the time +to do it carefully. + +But let's look, first of all, +at the discrete-time case. + +And the statement that I'm +making is that if I have two + +discrete-time sinusoidal signals +at two different + +frequencies, and if these +frequencies are separated by + +an integer multiple of 2 pi-- +namely if omega_2 is equal to + +omega_1 + 2 pi times +an integer m-- + +when I substitute this into this +expression, because of + +the fact that n is also an +integer, I'll have m * n as an + +integer multiple of 2 pi. + +And that term, of course, will +disappear because of the + +periodicity of the sinusoid, +and these two + +sequences will be equal. + +On the other hand in the +continuous-time case, since t + +is not restricted to be an +integer variable, for + +different values of omega_1 and +omega_2, these sinusoidal + +signals will always +be different. + +OK. + +Now, many of the issues that +I've raised so far, in + +relation to sinusoidal signals, +are elaborated on in + +more detail in the text. + +And of course, you'll have an +opportunity to exercise some + +of this as you work through +the video course manual. + +Let me stress that sinusoidal +signals will play an extremely + +important role for us as +building blocks for general + +signals and descriptions of +systems, and leads to the + +whole concept Fourier analysis, +which is very + +heavily exploited throughout +the course. + +What I'd now like to turn to is +another class of important + +building blocks. + +And in fact, we'll see that +under certain conditions, + +these relate strongly to +sinusoidal signals, namely the + +class of real and complex +exponentials. + +Let me begin, first of all, with +the real exponential, and + +in particular, in the +continuous-time case. + +A real continuous-time +exponential is mathematically + +expressed, as I indicate here, +x(t) = C e ^ (a t), where for + +the real exponential, C and +a are real numbers. + +And that's what we mean by +the real exponential. + +Shortly, we'll also consider +complex exponentials, where + +these numbers can then +become complex. + +So this is an exponential +function. + +And for example, if the +parameter a is positive, that + +means that we have a growing +exponential function. + +If the parameter a is negative, +then that means that + +we have a decaying exponential +function. + +Now, somewhat as an aside, it's +kind of interesting to + +note that for exponentials, a +time shift corresponds to a + +scale change, which is somewhat +different than what + +happens with sinusoids. + +In the sinusoidal case, we saw +that a time shift corresponded + +to a phase change. + +With the real exponential, a +time shift, as it turns out, + +corresponds to simply +changing the scale. + +There's nothing particularly +crucial or + +exciting about that. + +And in fact, perhaps stressing +it is a little misleading. + +For general functions, of +course, about all that you can + +say about what happens when you +implement a time shift is + +that it implements +a time shift. + +OK. + +So here's the real +exponential. + +Just C e ^ (a t). + +Let's look at the real +exponential, now, in the + +discrete-time case. + +And in the discrete-time case, +we have several alternate ways + +of expressing it. + +We can express the real +exponential in the form C e ^ + +(beta n), or as we'll find more +convenient, in part for a + +reason at I'll indicate shortly, +we can rewrite this + +as C alpha ^ n, where of course, +alpha = e ^ beta. + +More typically in the +discrete-time case, we'll + +express the exponential +as C alpha ^ n. + +So for example, this becomes, +essentially, a geometric + +series or progression +as n continues for + +certain values of alpha. + +Here for example, we have for +alpha greater than 0, first of + +all on the top, the case where +the magnitude of alpha is + +greater than 1, so that the +sequence is exponentially or + +geometrically growing. + +On the bottom, again with alpha +positive, but now with + +its magnitude less than 1, we +have a geometric progression + +that is exponentially or +geometrically decaying. + +OK. + +So this, in both of these +cases, is with alpha + +greater than 0. + +Now the function that we're +talking about is alpha ^ n. + +And of course, what you can +see is that if alpha is + +negative instead of positive, +then when n is even, that + +minus sign is going +to disappear. + +When n is odd, there will +be a minus sign. + +And so for alpha negative, the +sequence is going to alternate + +positive and negative values. + +So for example, here we have +alpha negative, with its + +magnitude less than 1. + +And you can see that, again, +its envelope decays + +geometrically, and the values +alternate in sign. + +And here we have the magnitude +of alpha greater than 1, with + +alpha negative. + +Again, they alternate in sign, +and of course it's growing + +geometrically. + +Now, if you think about alpha +positive and go back to the + +expression that I have at the +top, namely C alpha ^ n. + +With alpha positive, you can +see a straightforward + +relationship between +alpha and beta. + +Namely, beta is the natural +logarithm of alpha. + +Something to think +about is what + +happens if alpha is negative? + +Which is, of course, a very +important and useful class of + +real discrete-time exponentials +also. + +Well, it turns out that with +alpha negative, if you try to + +express it as C e ^ (beta n), +then beta comes out to be an + +imaginary number. + +And that is one, but not the +only reason why, in the + +discrete-time case, it's often +most convenient to phrase real + +exponentials in the form alpha ^ +n, rather than e ^ (beta n). + +In other words, to express them +in this form rather than + +in this form. + +Those are real exponentials, +continuous-time and + +discrete-time. + +Now let's look at the +continuous-time complex + +exponential. + +And what I mean by a complex +exponential, again, is an + +exponential of the +form C e ^ (a t). + +But in this case, we allow the +parameters C and a to be + +complex numbers. + +And let's just track this +through algebraically. + +If C and a are complex numbers, +let's write C in + +polar form, so it has a +magnitude and an angle. + +Let's write a in rectangular +form, so it has a real part + +and an imaginary part. + +And when we substitute these +two in here, combine some + +things together-- + +well actually, I haven't +combined yet. + +I have this for the amplitude +factor, and this for the + +exponential factor. + +I can now pull out of this the +term corresponding to e ^ (r + +t), and combine the imaginary +parts together. + +And I come down to the +expression that I have here. + +So following this further, an +exponential of this form, e ^ + +(j omega) or e ^ (j phi), using +Euler's relation, can be + +expressed as the sum of a cosine +plus j times a sine. + +And so that corresponds +to this factor. + +And then there is this +time-varying amplitude factor + +on top of it. + +Finally putting those together, +we end up with the + +expression that I show +on the bottom. + +And what this corresponds to are +two sinusoidal signals, 90 + +degrees out of phase, as +indicated by the fact that + +there's a cosine and a sine. + +So there's a real part and +an imaginary part, with + +sinusoidal components 90 degrees +out of phase, and a + +time-varying amplitude factor, +which is a real exponential. + +So it's a sinusoid multiplied by +a real exponential in both + +the real part and the +imaginary part. + +And let's just see what one of +those terms might look like. + +What I've indicated at the top +is a sinusoidal signal with a + +time-varying exponential +envelope, or an envelope which + +is a real exponential, and in +particular which is growing, + +namely with r greater than 0. + +And on the bottom, I've +indicated the same thing with + +r less than 0. + +And this kind of sinusoidal +signal, by the way, is + +typically referred to as +a damped sinusoid. + +So with r negative, what we have +in the real and imaginary + +parts are damped sinusoids. + +And the sinusoidal components of +that are 90 degrees out of + +phase, in the real part and +in the imaginary part. + +OK. + +Now, in the discrete-time case, +we have more or less the + +same kind of outcome. + +In particular we'll make +reference to our complex + +exponentials in the +discrete-time case. + +The expression for the complex +exponential looks very much + +like the expression for the real +exponential, except that + +now we have complex factors. + +So C and alpha are +complex numbers. + +And again, if we track through +the algebra, and get to a + +point where we have a real +exponential multiplied by a + +factor which is a purely +imaginary exponential, apply + +Euler's relationship to this, we +then finally come down to a + +sequence, which has a real +exponential amplitude + +multiplying one sinusoid +in the real part. + +And in the imaginary part, +exactly the same kind of + +exponential multiplying a +sinusoid that's 90 degrees out + +of phase from that. + +And so if we look at what one +of these factors might look + +like, it's what we would expect +given the analogy with + +the continuous-time case. + +Namely, it's a sinusoidal +sequence with a real + +exponential envelope. + +In the case where alpha +is positive, then + +it's a growing envelope. + +In the case where alpha +is negative-- + +I'm sorry-- + +where the magnitude of alpha +is greater than 1, it's a + +growing exponential envelope. + +Where the magnitude of alpha +is less than 1, it's a + +decaying exponential envelope. + +And so I've illustrated +that here. + +Here we have the magnitude +of alpha greater than 1. + +And here we have the magnitude +of alpha less than 1. + +In both cases, sinusoidal +sequences underneath the + +envelope, and then an envelope +that is dictated by what the + +magnitude of alpha is. + +OK. + +Now, in the discrete-time case, +then, we have results + +similar to the continuous-time +case. + +Namely, components in a real and +imaginary part that have a + +real exponential factor +times a sinusoid. + +Of course, if the magnitude of +alpha is equal to 1, then this + +factor disappears, +or is equal to 1. + +And this factor is equal to 1. + +And so we have sinusoids +in both the real + +and imaginary parts. + +Now, one can ask whether, +in general, the complex + +exponential with the magnitude +of alpha equal to 1 is + +periodic or not periodic. + +And the clue to that can be +inferred by examining this + +expression. + +In particular, in the +discrete-time case with the + +magnitude of alpha equal to 1, +we have pure sinusoids in the + +real part and the +imaginary part. + +And in fact, in a +continuous-time case with r + +equal to 0, we have sinusoids +in the real part and the + +imaginary part. + +In a continuous-time case when +we have a pure complex + +exponential, so that the terms +aren't exponentially growing + +or decaying, those + +exponentials are always periodic. + +Because, of course, the real +and imaginary sinusoidal + +components are periodic. + +In the discrete-time case, we +know that the sinusoids may or + +may not be periodic, depending +on the value of omega_0. + +And so in fact, in the +discrete-time case, the + +exponential e ^ (j omega_0 n), +that I've indicated here, may + +or may not be periodic depending +on what the value of + +omega_0 is. + +OK. + +Now, to summarize, in this +lecture I've introduced and + +discussed a number of important +basic signals. + +In particular, sinusoids and +real and complex exponentials. + +One of the important outcomes of +the discussion, emphasized + +further in the text, is that +there are some very important + +similarities between them. + +But there are also some very +important differences. + +And these differences will +surface when we exploit + +sinusoids and complex +exponentials as basic building + +blocks for more general +continuous-time and + +discrete-time signals. + +In the next lecture, what I'll +discuss are some other very + +important building blocks, +namely, what are referred to + +as step signals and +impulse signals. + +And those, together with the +sinusoidal signals and + +exponentials as we've talked +about today, will really form + +the cornerstone for, +essentially, all of the signal + +and system analysis that we'll +be dealing with for the + +remainder of course. + +Thank you. \ No newline at end of file diff --git a/7_hOHxaaxGE.txt b/7_hOHxaaxGE.txt new file mode 100644 index 0000000000000000000000000000000000000000..b66d976c5eb1fdb4da9e72f7ce4873b40c74bcee --- /dev/null +++ b/7_hOHxaaxGE.txt @@ -0,0 +1,507 @@ +align:start position:0% + +and finally to end this piece of the + + align:start position:0% +and finally to end this piece of the + + + align:start position:0% +and finally to end this piece of the +tutorial I'd like to encourage you to + + align:start position:0% +tutorial I'd like to encourage you to + + + align:start position:0% +tutorial I'd like to encourage you to +use your imagination think of lighting + + align:start position:0% +use your imagination think of lighting + + + align:start position:0% +use your imagination think of lighting +that's not necessarily in the textbooks + + align:start position:0% +that's not necessarily in the textbooks + + + align:start position:0% +that's not necessarily in the textbooks +look at this for example it's a device + + align:start position:0% +look at this for example it's a device + + + align:start position:0% +look at this for example it's a device +that you'll be seeing a great deal of in + + align:start position:0% +that you'll be seeing a great deal of in + + + align:start position:0% +that you'll be seeing a great deal of in +our virtual tool of lighting which + + align:start position:0% +our virtual tool of lighting which + + + align:start position:0% +our virtual tool of lighting which +you'll get to later I do not place it on + + align:start position:0% +you'll get to later I do not place it on + + + align:start position:0% +you'll get to later I do not place it on +the light box I use the light box as a + + align:start position:0% +the light box I use the light box as a + + + align:start position:0% +the light box I use the light box as a +light source as you see in this image + + align:start position:0% +light source as you see in this image + + + align:start position:0% +light source as you see in this image +because of its transparency and it's + + align:start position:0% +because of its transparency and it's + + + align:start position:0% +because of its transparency and it's +actually quite beautiful just as + + align:start position:0% +actually quite beautiful just as + + + align:start position:0% +actually quite beautiful just as +something itself I put it on my flatbed + + align:start position:0% +something itself I put it on my flatbed + + + align:start position:0% +something itself I put it on my flatbed +scanner but this is not a scanned image + + align:start position:0% +scanner but this is not a scanned image + + + align:start position:0% +scanner but this is not a scanned image +I'm actually using the light from the + + align:start position:0% +I'm actually using the light from the + + + align:start position:0% +I'm actually using the light from the +flatbed scanner as you can see in this + + align:start position:0% +flatbed scanner as you can see in this + + + align:start position:0% +flatbed scanner as you can see in this +image sometimes it could work when you + + align:start position:0% +image sometimes it could work when you + + + align:start position:0% +image sometimes it could work when you +get light from the side as it is in this + + align:start position:0% +get light from the side as it is in this + + + align:start position:0% +get light from the side as it is in this +case and another idea that perhaps you + + align:start position:0% +case and another idea that perhaps you + + + align:start position:0% +case and another idea that perhaps you +haven't thought about is to use a small + + align:start position:0% +haven't thought about is to use a small + + + align:start position:0% +haven't thought about is to use a small +LED flashlight if you want to image a + + align:start position:0% +LED flashlight if you want to image a + + + align:start position:0% +LED flashlight if you want to image a +very small area of your device here + + align:start position:0% +very small area of your device here + + + align:start position:0% +very small area of your device here +we're just photographing the spiral + + align:start position:0% +we're just photographing the spiral + + + align:start position:0% +we're just photographing the spiral +which measures about two and a half + + align:start position:0% +which measures about two and a half + + + align:start position:0% +which measures about two and a half +centimeters across all I did was shined + + align:start position:0% +centimeters across all I did was shined + + + align:start position:0% +centimeters across all I did was shined +an LED flashlight on to that area around + + align:start position:0% +an LED flashlight on to that area around + + + align:start position:0% +an LED flashlight on to that area around +the area it we get lighting fall off so + + align:start position:0% +the area it we get lighting fall off so + + + align:start position:0% +the area it we get lighting fall off so +we decided only to image this particular + + align:start position:0% +we decided only to image this particular + + + align:start position:0% +we decided only to image this particular +piece in the device this is a image i + + align:start position:0% +piece in the device this is a image i + + + align:start position:0% +piece in the device this is a image i +started making a material called + + align:start position:0% +started making a material called + + + align:start position:0% +started making a material called +ferrofluid and just seeing actually is a + + align:start position:0% +ferrofluid and just seeing actually is a + + + align:start position:0% +ferrofluid and just seeing actually is a +close shot of this material it is oil + + align:start position:0% +close shot of this material it is oil + + + align:start position:0% +close shot of this material it is oil +that has suspended iron filings I put it + + align:start position:0% +that has suspended iron filings I put it + + + align:start position:0% +that has suspended iron filings I put it +on a glass slide under the glass slide + + align:start position:0% +on a glass slide under the glass slide + + + align:start position:0% +on a glass slide under the glass slide +is a yellow post-it and under the yellow + + align:start position:0% +is a yellow post-it and under the yellow + + + align:start position:0% +is a yellow post-it and under the yellow +posted are seven circular magnets and + + align:start position:0% +posted are seven circular magnets and + + + align:start position:0% +posted are seven circular magnets and +you're seeing the small iron particles + + align:start position:0% +you're seeing the small iron particles + + + align:start position:0% +you're seeing the small iron particles +respond to the magnets it's basically + + align:start position:0% +respond to the magnets it's basically + + + align:start position:0% +respond to the magnets it's basically +too tight a shot to see anything of + + align:start position:0% +too tight a shot to see anything of + + + align:start position:0% +too tight a shot to see anything of +value in this image I pulled away a bit + + align:start position:0% +value in this image I pulled away a bit + + + align:start position:0% +value in this image I pulled away a bit +and I see a little more of what's going + + align:start position:0% +and I see a little more of what's going + + + align:start position:0% +and I see a little more of what's going +on but basically the window panes become + + align:start position:0% +on but basically the window panes become + + + align:start position:0% +on but basically the window panes become +may + + align:start position:0% +may + + + align:start position:0% +may +too much of a distraction and it's not + + align:start position:0% +too much of a distraction and it's not + + + align:start position:0% +too much of a distraction and it's not +quite right and so I decided seeing how + + align:start position:0% +quite right and so I decided seeing how + + + align:start position:0% +quite right and so I decided seeing how +reflective the whole image could be to + + align:start position:0% +reflective the whole image could be to + + + align:start position:0% +reflective the whole image could be to +put a green card above it so now we're + + align:start position:0% +put a green card above it so now we're + + + align:start position:0% +put a green card above it so now we're +seeing a little bit of green reflecting + + align:start position:0% +seeing a little bit of green reflecting + + + align:start position:0% +seeing a little bit of green reflecting +off of the material it's just purely an + + align:start position:0% +off of the material it's just purely an + + + align:start position:0% +off of the material it's just purely an +aesthetic decision it's not clarifying + + align:start position:0% +aesthetic decision it's not clarifying + + + align:start position:0% +aesthetic decision it's not clarifying +anything but I'm starting to think that + + align:start position:0% +anything but I'm starting to think that + + + align:start position:0% +anything but I'm starting to think that +I might have an interesting image here + + align:start position:0% +I might have an interesting image here + + + align:start position:0% +I might have an interesting image here +and eventually I did wind up with this + + align:start position:0% +and eventually I did wind up with this + + + align:start position:0% +and eventually I did wind up with this +final image with the windowpane with the + + align:start position:0% +final image with the windowpane with the + + + align:start position:0% +final image with the windowpane with the +green card reflecting and if you really + + align:start position:0% +green card reflecting and if you really + + + align:start position:0% +green card reflecting and if you really +look carefully you see the mistake of a + + align:start position:0% +look carefully you see the mistake of a + + + align:start position:0% +look carefully you see the mistake of a +bad photographer because you see me + + align:start position:0% +bad photographer because you see me + + + align:start position:0% +bad photographer because you see me +although it's fun to play around with + + align:start position:0% +although it's fun to play around with + + + align:start position:0% +although it's fun to play around with +the children and asking them to find + + align:start position:0% +the children and asking them to find + + + align:start position:0% +the children and asking them to find +Feliz but this is an image that got a + + align:start position:0% +Feliz but this is an image that got a + + + align:start position:0% +Feliz but this is an image that got a +lot of notice when I made it a while ago + + align:start position:0% +lot of notice when I made it a while ago + + + align:start position:0% +lot of notice when I made it a while ago +and I was using my imagination in terms + + align:start position:0% +and I was using my imagination in terms + + + align:start position:0% +and I was using my imagination in terms +of trying to find a way of using light + + align:start position:0% +of trying to find a way of using light + + + align:start position:0% +of trying to find a way of using light +in perhaps a different way \ No newline at end of file diff --git a/7afYLl70cO0.txt b/7afYLl70cO0.txt new file mode 100644 index 0000000000000000000000000000000000000000..91e25965a5c81a3eb8aaa4d5f75ef7a8474bc7a1 --- /dev/null +++ b/7afYLl70cO0.txt @@ -0,0 +1,7579 @@ +align:start position:0% + +alright let's get started so I'm + + align:start position:0% +alright let's get started so I'm + + + align:start position:0% +alright let's get started so I'm +starting with this video here what's + + align:start position:0% +starting with this video here what's + + + align:start position:0% +starting with this video here what's +happening here is there's this mouse and + + align:start position:0% +happening here is there's this mouse and + + + align:start position:0% +happening here is there's this mouse and +you see there's like this fiber-optic + + align:start position:0% +you see there's like this fiber-optic + + + align:start position:0% +you see there's like this fiber-optic +cable going into its brain and the mouse + + align:start position:0% +cable going into its brain and the mouse + + + align:start position:0% +cable going into its brain and the mouse +is asleep right now + + align:start position:0% +is asleep right now + + + align:start position:0% +is asleep right now +and now the researchers are shining + + align:start position:0% +and now the researchers are shining + + + align:start position:0% +and now the researchers are shining +light into its brain a specific region + + align:start position:0% +light into its brain a specific region + + + align:start position:0% +light into its brain a specific region +of the brain to activate specific + + align:start position:0% +of the brain to activate specific + + + align:start position:0% +of the brain to activate specific +neurons in order to test whether they + + align:start position:0% +neurons in order to test whether they + + + align:start position:0% +neurons in order to test whether they +function and arousal and here you see + + align:start position:0% +function and arousal and here you see + + + align:start position:0% +function and arousal and here you see +the mouse is going to wake up there it + + align:start position:0% +the mouse is going to wake up there it + + + align:start position:0% +the mouse is going to wake up there it +goes it's awake now okay so for today's + + align:start position:0% +goes it's awake now okay so for today's + + + align:start position:0% +goes it's awake now okay so for today's +lecture we're gonna sort work towards + + align:start position:0% +lecture we're gonna sort work towards + + + align:start position:0% +lecture we're gonna sort work towards +understanding how this experiment works + + align:start position:0% +understanding how this experiment works + + + align:start position:0% +understanding how this experiment works +and we're gonna talk about how neurons + + align:start position:0% +and we're gonna talk about how neurons + + + align:start position:0% +and we're gonna talk about how neurons +function and how researchers are able to + + align:start position:0% +function and how researchers are able to + + + align:start position:0% +function and how researchers are able to +control that function in order to modify + + align:start position:0% +control that function in order to modify + + + align:start position:0% +control that function in order to modify +behavior in this case the arousal of + + align:start position:0% +behavior in this case the arousal of + + + align:start position:0% +behavior in this case the arousal of +this mouse okay so this is going to + + align:start position:0% +this mouse okay so this is going to + + + align:start position:0% +this mouse okay so this is going to +involved a particular type of cell in + + align:start position:0% +involved a particular type of cell in + + + align:start position:0% +involved a particular type of cell in +our body which is the neuron and neurons + + align:start position:0% +our body which is the neuron and neurons + + + align:start position:0% +our body which is the neuron and neurons +are highly specialized cells that have a + + align:start position:0% +are highly specialized cells that have a + + + align:start position:0% +are highly specialized cells that have a +function to transmit information from + + align:start position:0% +function to transmit information from + + + align:start position:0% +function to transmit information from +one part of the body to another okay and + + align:start position:0% +one part of the body to another okay and + + + align:start position:0% +one part of the body to another okay and +so neurons are highly polarized cells + + align:start position:0% +so neurons are highly polarized cells + + + align:start position:0% +so neurons are highly polarized cells +which you can see here on the left of + + align:start position:0% +which you can see here on the left of + + + align:start position:0% +which you can see here on the left of +this neuron you see this Arbor of + + align:start position:0% +this neuron you see this Arbor of + + + align:start position:0% +this neuron you see this Arbor of +protrusions which are called dendrites + + align:start position:0% +protrusions which are called dendrites + + + align:start position:0% +protrusions which are called dendrites +and then on this side of the cell body + + align:start position:0% +and then on this side of the cell body + + + align:start position:0% +and then on this side of the cell body +you see a single extension which is an + + align:start position:0% +you see a single extension which is an + + + align:start position:0% +you see a single extension which is an +axon and then the terminus of the axon + + align:start position:0% +axon and then the terminus of the axon + + + align:start position:0% +axon and then the terminus of the axon +over here and this nerve cell transmits + + align:start position:0% +over here and this nerve cell transmits + + + align:start position:0% +over here and this nerve cell transmits +information in a single direction it'll + + align:start position:0% +information in a single direction it'll + + + align:start position:0% +information in a single direction it'll +transmit information from this side to + + align:start position:0% +transmit information from this side to + + + align:start position:0% +transmit information from this side to +this side okay and these neurons are + + align:start position:0% +this side okay and these neurons are + + + align:start position:0% +this side okay and these neurons are +able to communicate with the each other + + align:start position:0% +able to communicate with the each other + + + align:start position:0% +able to communicate with the each other +and they communicate at the ends of the + + align:start position:0% +and they communicate at the ends of the + + + align:start position:0% +and they communicate at the ends of the +neuron which are known as synapses which + + align:start position:0% +neuron which are known as synapses which + + + align:start position:0% +neuron which are known as synapses which +I'll come back to and talk about later + + align:start position:0% +I'll come back to and talk about later + + + align:start position:0% +I'll come back to and talk about later +on in the lecture ok so neurons could be + + align:start position:0% +on in the lecture ok so neurons could be + + + align:start position:0% +on in the lecture ok so neurons could be +making synapses on this side and also + + align:start position:0% +making synapses on this side and also + + + align:start position:0% +making synapses on this side and also +making synapses on this side with other + + align:start position:0% +making synapses on this side with other + + + align:start position:0% +making synapses on this side with other +neurons + + align:start position:0% + + + + align:start position:0% + +okay so to start to unpack the function + + align:start position:0% +okay so to start to unpack the function + + + align:start position:0% +okay so to start to unpack the function +of this neuron and I should highlight + + align:start position:0% +of this neuron and I should highlight + + + align:start position:0% +of this neuron and I should highlight +that this this flow of information can + + align:start position:0% +that this this flow of information can + + + align:start position:0% +that this this flow of information can +occur over very long distances right + + align:start position:0% +occur over very long distances right + + + align:start position:0% +occur over very long distances right +your sciatic nerve extends from the base + + align:start position:0% +your sciatic nerve extends from the base + + + align:start position:0% +your sciatic nerve extends from the base +of your spine all the way down into your + + align:start position:0% +of your spine all the way down into your + + + align:start position:0% +of your spine all the way down into your +foot okay so that axon is a 1 meter in + + align:start position:0% +foot okay so that axon is a 1 meter in + + + align:start position:0% +foot okay so that axon is a 1 meter in +length so that's an extremely long + + align:start position:0% +length so that's an extremely long + + + align:start position:0% +length so that's an extremely long +distance to transmit information along a + + align:start position:0% +distance to transmit information along a + + + align:start position:0% +distance to transmit information along a +single cell and so we're gonna go from + + align:start position:0% +single cell and so we're gonna go from + + + align:start position:0% +single cell and so we're gonna go from +thinking about how signals are + + align:start position:0% +thinking about how signals are + + + align:start position:0% +thinking about how signals are +transmitted in single cells and this + + align:start position:0% +transmitted in single cells and this + + + align:start position:0% +transmitted in single cells and this +will evolve electrical sing signaling + + align:start position:0% +will evolve electrical sing signaling + + + align:start position:0% +will evolve electrical sing signaling +then we'll talk about synapses and how + + align:start position:0% +then we'll talk about synapses and how + + + align:start position:0% +then we'll talk about synapses and how +synapses function to communicate between + + align:start position:0% +synapses function to communicate between + + + align:start position:0% +synapses function to communicate between +neurons and this is going to involve + + align:start position:0% +neurons and this is going to involve + + + align:start position:0% +neurons and this is going to involve +also sort of understanding how certain + + align:start position:0% +also sort of understanding how certain + + + align:start position:0% +also sort of understanding how certain +antidepressants like prozac work and + + align:start position:0% +antidepressants like prozac work and + + + align:start position:0% +antidepressants like prozac work and +then we'll end by talking about how + + align:start position:0% +then we'll end by talking about how + + + align:start position:0% +then we'll end by talking about how +researchers did this experiment to wake + + align:start position:0% +researchers did this experiment to wake + + + align:start position:0% +researchers did this experiment to wake +up the mouse and it all starts with + + align:start position:0% +up the mouse and it all starts with + + + align:start position:0% +up the mouse and it all starts with +something that I told you about at the + + align:start position:0% +something that I told you about at the + + + align:start position:0% +something that I told you about at the +beginning of the semester which is that + + align:start position:0% +beginning of the semester which is that + + + align:start position:0% +beginning of the semester which is that +there the plasma membrane separates + + align:start position:0% +there the plasma membrane separates + + + align:start position:0% +there the plasma membrane separates +distinct compartments the outside of the + + align:start position:0% +distinct compartments the outside of the + + + align:start position:0% +distinct compartments the outside of the +cell from the cytoplasm and there are + + align:start position:0% +cell from the cytoplasm and there are + + + align:start position:0% +cell from the cytoplasm and there are +distinct ion concentrations on either + + align:start position:0% +distinct ion concentrations on either + + + align:start position:0% +distinct ion concentrations on either +side of this boundary okay so we're + + align:start position:0% +side of this boundary okay so we're + + + align:start position:0% +side of this boundary okay so we're +starting now talking about a single + + align:start position:0% +starting now talking about a single + + + align:start position:0% +starting now talking about a single +neuron cell and we're going to talk + + align:start position:0% +neuron cell and we're going to talk + + + align:start position:0% +neuron cell and we're going to talk +about a type of signal known as an + + align:start position:0% +about a type of signal known as an + + + align:start position:0% +about a type of signal known as an +electrical passion potential so we're + + align:start position:0% +electrical passion potential so we're + + + align:start position:0% +electrical passion potential so we're +going to talk about an action potential + + align:start position:0% +going to talk about an action potential + + + align:start position:0% +going to talk about an action potential +and what an action potential is is this + + align:start position:0% +and what an action potential is is this + + + align:start position:0% +and what an action potential is is this +an electrical signal that travels the + + align:start position:0% +an electrical signal that travels the + + + align:start position:0% +an electrical signal that travels the +length of the neuron okay so this action + + align:start position:0% +length of the neuron okay so this action + + + align:start position:0% +length of the neuron okay so this action +potential I'll abbreviate this ap so + + align:start position:0% +potential I'll abbreviate this ap so + + + align:start position:0% +potential I'll abbreviate this ap so +when I refer to AP I'm not referring to + + align:start position:0% +when I refer to AP I'm not referring to + + + align:start position:0% +when I refer to AP I'm not referring to +Advanced Placement but action potential + + align:start position:0% +Advanced Placement but action potential + + + align:start position:0% +Advanced Placement but action potential +okay so this is an electrical signal + + align:start position:0% + + + + align:start position:0% + +that travels the length of the axon in + + align:start position:0% +that travels the length of the axon in + + + align:start position:0% +that travels the length of the axon in +the neuron and so in order to have an + + align:start position:0% +the neuron and so in order to have an + + + align:start position:0% +the neuron and so in order to have an +electrical signal propagate we need some + + align:start position:0% +electrical signal propagate we need some + + + align:start position:0% +electrical signal propagate we need some +sort of electrical property that the + + align:start position:0% +sort of electrical property that the + + + align:start position:0% +sort of electrical property that the +cell has that enables this and so I + + align:start position:0% +cell has that enables this and so I + + + align:start position:0% +cell has that enables this and so I +showed you or I told you earlier in this + + align:start position:0% +showed you or I told you earlier in this + + + align:start position:0% +showed you or I told you earlier in this +aster how sodium ions are concentrated + + align:start position:0% +aster how sodium ions are concentrated + + + align:start position:0% +aster how sodium ions are concentrated +on the outside of the cell and potassium + + align:start position:0% +on the outside of the cell and potassium + + + align:start position:0% +on the outside of the cell and potassium +ions are concentrated on the inside you + + align:start position:0% +ions are concentrated on the inside you + + + align:start position:0% +ions are concentrated on the inside you +see here's the sodium gradient here + + align:start position:0% +see here's the sodium gradient here + + + align:start position:0% +see here's the sodium gradient here +potassium gradient here and now I'm + + align:start position:0% +potassium gradient here and now I'm + + + align:start position:0% +potassium gradient here and now I'm +gonna tell you how it is that this + + align:start position:0% +gonna tell you how it is that this + + + align:start position:0% +gonna tell you how it is that this +happens because this is + + align:start position:0% +happens because this is + + + align:start position:0% +happens because this is +thermodynamically not favored right + + align:start position:0% +thermodynamically not favored right + + + align:start position:0% +thermodynamically not favored right +these these ions would prefer by + + align:start position:0% +these these ions would prefer by + + + align:start position:0% +these these ions would prefer by +diffusion to be equal concentrations on + + align:start position:0% +diffusion to be equal concentrations on + + + align:start position:0% +diffusion to be equal concentrations on +both sides of this plasma membrane which + + align:start position:0% +both sides of this plasma membrane which + + + align:start position:0% +both sides of this plasma membrane which +means that the cell to shift this from + + align:start position:0% +means that the cell to shift this from + + + align:start position:0% +means that the cell to shift this from +equilibrium has to expend energy to set + + align:start position:0% +equilibrium has to expend energy to set + + + align:start position:0% +equilibrium has to expend energy to set +up this situation and so in the plasma + + align:start position:0% +up this situation and so in the plasma + + + align:start position:0% +up this situation and so in the plasma +membrane of the cell there is a protein + + align:start position:0% +membrane of the cell there is a protein + + + align:start position:0% +membrane of the cell there is a protein +it's an integral membrane protein and + + align:start position:0% +it's an integral membrane protein and + + + align:start position:0% +it's an integral membrane protein and +sits inside the plasma membrane so this + + align:start position:0% +sits inside the plasma membrane so this + + + align:start position:0% +sits inside the plasma membrane so this +here is the plasma membrane and this + + align:start position:0% +here is the plasma membrane and this + + + align:start position:0% +here is the plasma membrane and this +integral membrane protein is called a + + align:start position:0% +integral membrane protein is called a + + + align:start position:0% +integral membrane protein is called a +sodium potassium ATPase so it's going to + + align:start position:0% +sodium potassium ATPase so it's going to + + + align:start position:0% +sodium potassium ATPase so it's going to +have a subunit that hydrolyzes ATP to + + align:start position:0% +have a subunit that hydrolyzes ATP to + + + align:start position:0% +have a subunit that hydrolyzes ATP to +adp and the protein uses the energy of + + align:start position:0% +adp and the protein uses the energy of + + + align:start position:0% +adp and the protein uses the energy of +ATP hydrolysis to pump sodium ions up + + align:start position:0% +ATP hydrolysis to pump sodium ions up + + + align:start position:0% +ATP hydrolysis to pump sodium ions up +their concentration gradient so the + + align:start position:0% +their concentration gradient so the + + + align:start position:0% +their concentration gradient so the +sodium ions are going out of the cell + + align:start position:0% +sodium ions are going out of the cell + + + align:start position:0% +sodium ions are going out of the cell +and this is going against the flow that + + align:start position:0% +and this is going against the flow that + + + align:start position:0% +and this is going against the flow that +sodium would normally like to take which + + align:start position:0% +sodium would normally like to take which + + + align:start position:0% +sodium would normally like to take which +would be going downstream and it pumps + + align:start position:0% +would be going downstream and it pumps + + + align:start position:0% +would be going downstream and it pumps +potassium ions into the cytoplasm such + + align:start position:0% +potassium ions into the cytoplasm such + + + align:start position:0% +potassium ions into the cytoplasm such +that there's a higher concentration of + + align:start position:0% +that there's a higher concentration of + + + align:start position:0% +that there's a higher concentration of +potassium ions in the cytoplasm okay so + + align:start position:0% +potassium ions in the cytoplasm okay so + + + align:start position:0% +potassium ions in the cytoplasm okay so +these neurons expend a huge about a + + align:start position:0% +these neurons expend a huge about a + + + align:start position:0% +these neurons expend a huge about a +quarter amount a quarter of their ATP is + + align:start position:0% +quarter amount a quarter of their ATP is + + + align:start position:0% +quarter amount a quarter of their ATP is +used by pumping ions like this such that + + align:start position:0% +used by pumping ions like this such that + + + align:start position:0% +used by pumping ions like this such that +there is gradients of ions across the + + align:start position:0% +there is gradients of ions across the + + + align:start position:0% +there is gradients of ions across the +plasma membrane okay + + align:start position:0% +plasma membrane okay + + + align:start position:0% +plasma membrane okay +now if if one sodium ion was pumped out + + align:start position:0% +now if if one sodium ion was pumped out + + + align:start position:0% +now if if one sodium ion was pumped out +for every potassium ion pumped in + + align:start position:0% +for every potassium ion pumped in + + + align:start position:0% +for every potassium ion pumped in +there'd be no charge difference between + + align:start position:0% +there'd be no charge difference between + + + align:start position:0% +there'd be no charge difference between +the exterior and the cytoplasm but what + + align:start position:0% +the exterior and the cytoplasm but what + + + align:start position:0% +the exterior and the cytoplasm but what +happens in the plasma membrane is that + + align:start position:0% +happens in the plasma membrane is that + + + align:start position:0% +happens in the plasma membrane is that +in addition to the sodium potassium + + align:start position:0% +in addition to the sodium potassium + + + align:start position:0% +in addition to the sodium potassium +ATPase there are other channels that are + + align:start position:0% +ATPase there are other channels that are + + + align:start position:0% +ATPase there are other channels that are +present there are sodium channels these + + align:start position:0% +present there are sodium channels these + + + align:start position:0% +present there are sodium channels these +are mostly closed but there are some + + align:start position:0% +are mostly closed but there are some + + + align:start position:0% +are mostly closed but there are some +potassium channels that are leaky and + + align:start position:0% +potassium channels that are leaky and + + + align:start position:0% +potassium channels that are leaky and +they're basically leaking potassium from + + align:start position:0% +they're basically leaking potassium from + + + align:start position:0% +they're basically leaking potassium from +the cytoplasm out into the ectoplasm + + align:start position:0% +the cytoplasm out into the ectoplasm + + + align:start position:0% +the cytoplasm out into the ectoplasm +okay and if you have positive charges + + align:start position:0% +okay and if you have positive charges + + + align:start position:0% +okay and if you have positive charges +going out the cell then the inside of + + align:start position:0% +going out the cell then the inside of + + + align:start position:0% +going out the cell then the inside of +the membrane is going to have a net + + align:start position:0% +the membrane is going to have a net + + + align:start position:0% +the membrane is going to have a net +negative charge and the outside of the + + align:start position:0% +negative charge and the outside of the + + + align:start position:0% +negative charge and the outside of the +membrane is going to have a net positive + + align:start position:0% +membrane is going to have a net positive + + + align:start position:0% +membrane is going to have a net positive +charge okay and this charge across the + + align:start position:0% +charge okay and this charge across the + + + align:start position:0% +charge okay and this charge across the +membrane where you have positive on the + + align:start position:0% +membrane where you have positive on the + + + align:start position:0% +membrane where you have positive on the +outside and minus on the inside I should + + align:start position:0% +outside and minus on the inside I should + + + align:start position:0% +outside and minus on the inside I should +label this exterior and this is + + align:start position:0% +label this exterior and this is + + + align:start position:0% +label this exterior and this is +cytoplasm this voltage difference is + + align:start position:0% +cytoplasm this voltage difference is + + + align:start position:0% +cytoplasm this voltage difference is +known as the membrane potential okay so + + align:start position:0% +known as the membrane potential okay so + + + align:start position:0% +known as the membrane potential okay so +this is a membrane potential + + align:start position:0% + + + + align:start position:0% + +and it's an electrical potential across + + align:start position:0% +and it's an electrical potential across + + + align:start position:0% +and it's an electrical potential across +the membrane if you're an electrical + + align:start position:0% +the membrane if you're an electrical + + + align:start position:0% +the membrane if you're an electrical +engineer you can think of the plasma + + align:start position:0% +engineer you can think of the plasma + + + align:start position:0% +engineer you can think of the plasma +membrane as a capacitor okay so this + + align:start position:0% +membrane as a capacitor okay so this + + + align:start position:0% +membrane as a capacitor okay so this +plasma membrane is holding this charge + + align:start position:0% +plasma membrane is holding this charge + + + align:start position:0% +plasma membrane is holding this charge +difference across it okay and so there's + + align:start position:0% +difference across it okay and so there's + + + align:start position:0% +difference across it okay and so there's +a voltage across the membrane and in an + + align:start position:0% +a voltage across the membrane and in an + + + align:start position:0% +a voltage across the membrane and in an +arresting state the cell's resting + + align:start position:0% +arresting state the cell's resting + + + align:start position:0% +arresting state the cell's resting +potential is negative 70 millivolts okay + + align:start position:0% +potential is negative 70 millivolts okay + + + align:start position:0% +potential is negative 70 millivolts okay +so if the cell is not getting stimulated + + align:start position:0% +so if the cell is not getting stimulated + + + align:start position:0% +so if the cell is not getting stimulated +by something like a neurotransmitter the + + align:start position:0% +by something like a neurotransmitter the + + + align:start position:0% +by something like a neurotransmitter the +resting potential is negative 70 + + align:start position:0% +resting potential is negative 70 + + + align:start position:0% +resting potential is negative 70 +millivolts where the inside is negative + + align:start position:0% +millivolts where the inside is negative + + + align:start position:0% +millivolts where the inside is negative +and outside is positive okay + + align:start position:0% +and outside is positive okay + + + align:start position:0% +and outside is positive okay +so now I just wanted to find some terms + + align:start position:0% +so now I just wanted to find some terms + + + align:start position:0% +so now I just wanted to find some terms +that are gonna be useful for us when we + + align:start position:0% +that are gonna be useful for us when we + + + align:start position:0% +that are gonna be useful for us when we +talk about action potentials so when + + align:start position:0% +talk about action potentials so when + + + align:start position:0% +talk about action potentials so when +there's this negative inside potential a + + align:start position:0% + + + + align:start position:0% + +negative inside potential is referred to + + align:start position:0% +negative inside potential is referred to + + + align:start position:0% +negative inside potential is referred to +as polarized so it's polarized because + + align:start position:0% +as polarized so it's polarized because + + + align:start position:0% +as polarized so it's polarized because +there's a polarity across this membrane + + align:start position:0% +there's a polarity across this membrane + + + align:start position:0% +there's a polarity across this membrane +where one side is positive and the other + + align:start position:0% +where one side is positive and the other + + + align:start position:0% +where one side is positive and the other +side is negative okay + + align:start position:0% +side is negative okay + + + align:start position:0% +side is negative okay +so polarized refers to if there's a + + align:start position:0% +so polarized refers to if there's a + + + align:start position:0% +so polarized refers to if there's a +negative inside potential so the resting + + align:start position:0% +negative inside potential so the resting + + + align:start position:0% +negative inside potential so the resting +state of the side is there's a polarized + + align:start position:0% +state of the side is there's a polarized + + + align:start position:0% +state of the side is there's a polarized +it's polarized however the cell can lose + + align:start position:0% +it's polarized however the cell can lose + + + align:start position:0% +it's polarized however the cell can lose +this polarity and not have a charge + + align:start position:0% +this polarity and not have a charge + + + align:start position:0% +this polarity and not have a charge +differential or it can flip and be + + align:start position:0% +differential or it can flip and be + + + align:start position:0% +differential or it can flip and be +positive on the inside and when that + + align:start position:0% +positive on the inside and when that + + + align:start position:0% +positive on the inside and when that +happens if there's either zero or + + align:start position:0% +happens if there's either zero or + + + align:start position:0% +happens if there's either zero or +positive inside potential this is + + align:start position:0% +positive inside potential this is + + + align:start position:0% +positive inside potential this is +referred to as depolarized + + align:start position:0% + + + + align:start position:0% + +okay anyone have an idea as to how the + + align:start position:0% +okay anyone have an idea as to how the + + + align:start position:0% +okay anyone have an idea as to how the +cell would flip the potential what would + + align:start position:0% +cell would flip the potential what would + + + align:start position:0% +cell would flip the potential what would +have to happen in the plasma membrane to + + align:start position:0% +have to happen in the plasma membrane to + + + align:start position:0% +have to happen in the plasma membrane to +flip this potential and depolarize the + + align:start position:0% +flip this potential and depolarize the + + + align:start position:0% +flip this potential and depolarize the +cell yes Steven so Steven suggested + + align:start position:0% +cell yes Steven so Steven suggested + + + align:start position:0% +cell yes Steven so Steven suggested +opening ion channels which ion channels + + align:start position:0% +opening ion channels which ion channels + + + align:start position:0% +opening ion channels which ion channels +would you open yeah so Steven suggested + + align:start position:0% +would you open yeah so Steven suggested + + + align:start position:0% +would you open yeah so Steven suggested +if you open these is going to depolarize + + align:start position:0% +if you open these is going to depolarize + + + align:start position:0% +if you open these is going to depolarize +the cell because remember sodium is high + + align:start position:0% +the cell because remember sodium is high + + + align:start position:0% +the cell because remember sodium is high +on the outside out here and so if you + + align:start position:0% +on the outside out here and so if you + + + align:start position:0% +on the outside out here and so if you +open these channels positive ions are + + align:start position:0% +open these channels positive ions are + + + align:start position:0% +open these channels positive ions are +gonna flow in and that's going to make + + align:start position:0% +gonna flow in and that's going to make + + + align:start position:0% +gonna flow in and that's going to make +this less negative and this less + + align:start position:0% +this less negative and this less + + + align:start position:0% +this less negative and this less +positive okay so this is the situation + + align:start position:0% +positive okay so this is the situation + + + align:start position:0% +positive okay so this is the situation +here right where these sodium channels + + align:start position:0% +here right where these sodium channels + + + align:start position:0% +here right where these sodium channels +open and the sodium channels are the + + align:start position:0% +open and the sodium channels are the + + + align:start position:0% +open and the sodium channels are the +sodium ions rushing in is going to + + align:start position:0% +sodium ions rushing in is going to + + + align:start position:0% +sodium ions rushing in is going to +create a depolarization where you now + + align:start position:0% +create a depolarization where you now + + + align:start position:0% +create a depolarization where you now +flip the potential and there's a greater + + align:start position:0% +flip the potential and there's a greater + + + align:start position:0% +flip the potential and there's a greater +positive charge on the inside of the + + align:start position:0% +positive charge on the inside of the + + + align:start position:0% +positive charge on the inside of the +plasma membrane + + align:start position:0% +plasma membrane + + + align:start position:0% +plasma membrane +okay everyone see how because the sodium + + align:start position:0% +okay everyone see how because the sodium + + + align:start position:0% +okay everyone see how because the sodium +ions are going to just go downstream + + align:start position:0% +ions are going to just go downstream + + + align:start position:0% +ions are going to just go downstream +their higher concentration out here so + + align:start position:0% +their higher concentration out here so + + + align:start position:0% +their higher concentration out here so +just by opening these channels the cell + + align:start position:0% +just by opening these channels the cell + + + align:start position:0% +just by opening these channels the cell +doesn't have to do any work to do this + + align:start position:0% +doesn't have to do any work to do this + + + align:start position:0% +doesn't have to do any work to do this +sodium is just going to flow down its + + align:start position:0% +sodium is just going to flow down its + + + align:start position:0% +sodium is just going to flow down its +gradient into the cytoplasm + + align:start position:0% + + + + align:start position:0% + +okay so what an action potential is is + + align:start position:0% +okay so what an action potential is is + + + align:start position:0% +okay so what an action potential is is +it's a transient dope depolarization of + + align:start position:0% +it's a transient dope depolarization of + + + align:start position:0% +it's a transient dope depolarization of +the nerve cell okay so the action + + align:start position:0% +the nerve cell okay so the action + + + align:start position:0% +the nerve cell okay so the action +potential or ap is a transient + + align:start position:0% + + + + align:start position:0% + +depolarization of the neuron which means + + align:start position:0% +depolarization of the neuron which means + + + align:start position:0% +depolarization of the neuron which means +it doesn't just depolarize and stay + + align:start position:0% +it doesn't just depolarize and stay + + + align:start position:0% +it doesn't just depolarize and stay +depolarized + + align:start position:0% +depolarized + + + align:start position:0% +depolarized +but it depolarizes and then restores + + align:start position:0% +but it depolarizes and then restores + + + align:start position:0% +but it depolarizes and then restores +itself back to the resting polarity and + + align:start position:0% +itself back to the resting polarity and + + + align:start position:0% +itself back to the resting polarity and +so what you see when you measure the + + align:start position:0% +so what you see when you measure the + + + align:start position:0% +so what you see when you measure the +voltage across the plasma membrane in + + align:start position:0% +voltage across the plasma membrane in + + + align:start position:0% +voltage across the plasma membrane in +the neuron you see that it can spike and + + align:start position:0% +the neuron you see that it can spike and + + + align:start position:0% +the neuron you see that it can spike and +depolarize but then it's rapidly + + align:start position:0% +depolarize but then it's rapidly + + + align:start position:0% +depolarize but then it's rapidly +restored to its resting state okay so + + align:start position:0% +restored to its resting state okay so + + + align:start position:0% +restored to its resting state okay so +it's a transient process and when we + + align:start position:0% +it's a transient process and when we + + + align:start position:0% +it's a transient process and when we +think about the neuron at higher + + align:start position:0% +think about the neuron at higher + + + align:start position:0% +think about the neuron at higher +resolution what you're going to see is + + align:start position:0% +resolution what you're going to see is + + + align:start position:0% +resolution what you're going to see is +not only is it transient but it's also a + + align:start position:0% +not only is it transient but it's also a + + + align:start position:0% +not only is it transient but it's also a +traveling wave that propagates along the + + align:start position:0% +traveling wave that propagates along the + + + align:start position:0% +traveling wave that propagates along the +entire length of the cell okay so this + + align:start position:0% +entire length of the cell okay so this + + + align:start position:0% +entire length of the cell okay so this +is also a traveling wave and one thing + + align:start position:0% +is also a traveling wave and one thing + + + align:start position:0% +is also a traveling wave and one thing +that you can notice about these neurons + + align:start position:0% +that you can notice about these neurons + + + align:start position:0% +that you can notice about these neurons +or the action potentials here is that + + align:start position:0% +or the action potentials here is that + + + align:start position:0% +or the action potentials here is that +they all depolarize to the same extent + + align:start position:0% +they all depolarize to the same extent + + + align:start position:0% +they all depolarize to the same extent +so they all depolarize to this positive + + align:start position:0% +so they all depolarize to this positive + + + align:start position:0% +so they all depolarize to this positive +50 millivolts and so this illustrates a + + align:start position:0% +50 millivolts and so this illustrates a + + + align:start position:0% +50 millivolts and so this illustrates a +key property of neurons and that the the + + align:start position:0% +key property of neurons and that the the + + + align:start position:0% +key property of neurons and that the the +level of activity of a neuron is not + + align:start position:0% +level of activity of a neuron is not + + + align:start position:0% +level of activity of a neuron is not +determined by the size of this action + + align:start position:0% +determined by the size of this action + + + align:start position:0% +determined by the size of this action +potential this action potential is an + + align:start position:0% +potential this action potential is an + + + align:start position:0% +potential this action potential is an +all-or-nothing event it either happens + + align:start position:0% +all-or-nothing event it either happens + + + align:start position:0% +all-or-nothing event it either happens +or it doesn't and when it happens it + + align:start position:0% +or it doesn't and when it happens it + + + align:start position:0% +or it doesn't and when it happens it +depolarizes to the same level okay so + + align:start position:0% +depolarizes to the same level okay so + + + align:start position:0% +depolarizes to the same level okay so +the action potential is all or nothing + + align:start position:0% + + + + align:start position:0% + +you can think of it as a binary signal + + align:start position:0% +you can think of it as a binary signal + + + align:start position:0% +you can think of it as a binary signal +and therefore the way that neurons + + align:start position:0% +and therefore the way that neurons + + + align:start position:0% +and therefore the way that neurons +encode sort of the magnitude of + + align:start position:0% +encode sort of the magnitude of + + + align:start position:0% +encode sort of the magnitude of +activation is not through the level of + + align:start position:0% +activation is not through the level of + + + align:start position:0% +activation is not through the level of +depolarization of a single action + + align:start position:0% +depolarization of a single action + + + align:start position:0% +depolarization of a single action +potential but it is able to distinguish + + align:start position:0% +potential but it is able to distinguish + + + align:start position:0% +potential but it is able to distinguish +between different frequencies of action + + align:start position:0% +between different frequencies of action + + + align:start position:0% +between different frequencies of action +potentials that are propagating along + + align:start position:0% +potentials that are propagating along + + + align:start position:0% +potentials that are propagating along +the neuron + + align:start position:0% +the neuron + + + align:start position:0% +the neuron +okay so signal strength in this case is + + align:start position:0% +okay so signal strength in this case is + + + align:start position:0% +okay so signal strength in this case is +related to the frequency of action + + align:start position:0% +related to the frequency of action + + + align:start position:0% +related to the frequency of action +potentials firing + + align:start position:0% + + + + align:start position:0% + +okay so now we're gonna unpack how it is + + align:start position:0% +okay so now we're gonna unpack how it is + + + align:start position:0% +okay so now we're gonna unpack how it is +a nerve cell fires in action potential + + align:start position:0% +a nerve cell fires in action potential + + + align:start position:0% +a nerve cell fires in action potential +and how it propagates along the entire + + align:start position:0% +and how it propagates along the entire + + + align:start position:0% +and how it propagates along the entire +cell length right in the case of the + + align:start position:0% +cell length right in the case of the + + + align:start position:0% +cell length right in the case of the +sciatic nerve this has to happen across + + align:start position:0% +sciatic nerve this has to happen across + + + align:start position:0% +sciatic nerve this has to happen across +an entire meter okay that's a very long + + align:start position:0% +an entire meter okay that's a very long + + + align:start position:0% +an entire meter okay that's a very long +distance to propagate this change in + + align:start position:0% +distance to propagate this change in + + + align:start position:0% +distance to propagate this change in +electrical signal at least for a cell + + align:start position:0% +electrical signal at least for a cell + + + align:start position:0% +electrical signal at least for a cell +and so we're going to talk about the + + align:start position:0% +and so we're going to talk about the + + + align:start position:0% +and so we're going to talk about the +mechanism and I'm going to start at the + + align:start position:0% +mechanism and I'm going to start at the + + + align:start position:0% +mechanism and I'm going to start at the +beginning when this action potential + + align:start position:0% +beginning when this action potential + + + align:start position:0% +beginning when this action potential +initiates so we'll start at the + + align:start position:0% +initiates so we'll start at the + + + align:start position:0% +initiates so we'll start at the +initiation of the action potential so + + align:start position:0% +initiation of the action potential so + + + align:start position:0% +initiation of the action potential so +how is it that this nerve cell is told + + align:start position:0% +how is it that this nerve cell is told + + + align:start position:0% +how is it that this nerve cell is told +to start depolarizing at the dendrites + + align:start position:0% +to start depolarizing at the dendrites + + + align:start position:0% +to start depolarizing at the dendrites +okay because there's gonna be another + + align:start position:0% +okay because there's gonna be another + + + align:start position:0% +okay because there's gonna be another +neuron here which is going to + + align:start position:0% +neuron here which is going to + + + align:start position:0% +neuron here which is going to +communicate to this neuron over here to + + align:start position:0% +communicate to this neuron over here to + + + align:start position:0% +communicate to this neuron over here to +tell it to start depolarizing okay it + + align:start position:0% +tell it to start depolarizing okay it + + + align:start position:0% +tell it to start depolarizing okay it +does this at the location known as the + + align:start position:0% +does this at the location known as the + + + align:start position:0% +does this at the location known as the +synapse which is basically the sort of + + align:start position:0% +synapse which is basically the sort of + + + align:start position:0% +synapse which is basically the sort of +the connection between the two neurons + + align:start position:0% +the connection between the two neurons + + + align:start position:0% +the connection between the two neurons +and the way this process is initiated is + + align:start position:0% +and the way this process is initiated is + + + align:start position:0% +and the way this process is initiated is +similar to the type of signaling that + + align:start position:0% +similar to the type of signaling that + + + align:start position:0% +similar to the type of signaling that +you saw in the past few lectures where + + align:start position:0% +you saw in the past few lectures where + + + align:start position:0% +you saw in the past few lectures where +you have a ligand and a receptor okay in + + align:start position:0% +you have a ligand and a receptor okay in + + + align:start position:0% +you have a ligand and a receptor okay in +this case the ligand + + align:start position:0% + + + + align:start position:0% + +the ligand is going to be what's known + + align:start position:0% +the ligand is going to be what's known + + + align:start position:0% +the ligand is going to be what's known +as a neurotransmitter which is a small + + align:start position:0% +as a neurotransmitter which is a small + + + align:start position:0% +as a neurotransmitter which is a small +molecule and I'll show you some later on + + align:start position:0% +molecule and I'll show you some later on + + + align:start position:0% +molecule and I'll show you some later on +and the receptor is going to be a + + align:start position:0% +and the receptor is going to be a + + + align:start position:0% +and the receptor is going to be a +receptor the binds to this log and but + + align:start position:0% +receptor the binds to this log and but + + + align:start position:0% +receptor the binds to this log and but +in this case rather than being something + + align:start position:0% +in this case rather than being something + + + align:start position:0% +in this case rather than being something +like a g-protein coupled receptor or a + + align:start position:0% +like a g-protein coupled receptor or a + + + align:start position:0% +like a g-protein coupled receptor or a +receptor tyrosine kinase the receptor is + + align:start position:0% +receptor tyrosine kinase the receptor is + + + align:start position:0% +receptor tyrosine kinase the receptor is +going to be an ion channel okay so the + + align:start position:0% +going to be an ion channel okay so the + + + align:start position:0% +going to be an ion channel okay so the +receptor is going to be an ion channel + + align:start position:0% + + + + align:start position:0% + +okay and so you see one example on the + + align:start position:0% +okay and so you see one example on the + + + align:start position:0% +okay and so you see one example on the +slide up here where here's a receptor + + align:start position:0% +slide up here where here's a receptor + + + align:start position:0% +slide up here where here's a receptor +and these receptors are what are known + + align:start position:0% +and these receptors are what are known + + + align:start position:0% +and these receptors are what are known +as ligand gated sodium or ion channels + + align:start position:0% +as ligand gated sodium or ion channels + + + align:start position:0% +as ligand gated sodium or ion channels +in this case it's a sodium channel so + + align:start position:0% +in this case it's a sodium channel so + + + align:start position:0% +in this case it's a sodium channel so +it's going to be whether or not it's + + align:start position:0% +it's going to be whether or not it's + + + align:start position:0% +it's going to be whether or not it's +open depends on the presence of the + + align:start position:0% +open depends on the presence of the + + + align:start position:0% +open depends on the presence of the +ligand so if we take a neurotransmitter + + align:start position:0% +ligand so if we take a neurotransmitter + + + align:start position:0% +ligand so if we take a neurotransmitter +like serotonin if it's not bound to the + + align:start position:0% +like serotonin if it's not bound to the + + + align:start position:0% +like serotonin if it's not bound to the +receptor the receptor is closed but if + + align:start position:0% +receptor the receptor is closed but if + + + align:start position:0% +receptor the receptor is closed but if +serotonin binds to this receptor it + + align:start position:0% +serotonin binds to this receptor it + + + align:start position:0% +serotonin binds to this receptor it +opens up the channel which can + + align:start position:0% +opens up the channel which can + + + align:start position:0% +opens up the channel which can +selectively let in a type of ion in this + + align:start position:0% +selectively let in a type of ion in this + + + align:start position:0% +selectively let in a type of ion in this +case sodium right in this case this is + + align:start position:0% +case sodium right in this case this is + + + align:start position:0% +case sodium right in this case this is +an activating channel because letting in + + align:start position:0% +an activating channel because letting in + + + align:start position:0% +an activating channel because letting in +sodium is going to depolarize the cell + + align:start position:0% +sodium is going to depolarize the cell + + + align:start position:0% +sodium is going to depolarize the cell +okay so this ligand receptor binding + + align:start position:0% +okay so this ligand receptor binding + + + align:start position:0% +okay so this ligand receptor binding +uses a ligand gated there's a ligand + + align:start position:0% +uses a ligand gated there's a ligand + + + align:start position:0% +uses a ligand gated there's a ligand +gated sodium channel and it's this + + align:start position:0% +gated sodium channel and it's this + + + align:start position:0% +gated sodium channel and it's this +ligand gated sodium channel which starts + + align:start position:0% +ligand gated sodium channel which starts + + + align:start position:0% +ligand gated sodium channel which starts +the depolarization + + align:start position:0% + + + + align:start position:0% + +okay so that's how that's how you sort + + align:start position:0% +okay so that's how that's how you sort + + + align:start position:0% +okay so that's how that's how you sort +of like knock over the first domino + + align:start position:0% +of like knock over the first domino + + + align:start position:0% +of like knock over the first domino +right but then there has to be some + + align:start position:0% +right but then there has to be some + + + align:start position:0% +right but then there has to be some +mechanism to propagate this along the + + align:start position:0% +mechanism to propagate this along the + + + align:start position:0% +mechanism to propagate this along the +length of a very long cell and so I'll + + align:start position:0% +length of a very long cell and so I'll + + + align:start position:0% +length of a very long cell and so I'll +tell you this involves a different type + + align:start position:0% +tell you this involves a different type + + + align:start position:0% +tell you this involves a different type +of sort of signaling mechanism from what + + align:start position:0% +of sort of signaling mechanism from what + + + align:start position:0% +of sort of signaling mechanism from what +you're used to thinking about because + + align:start position:0% +you're used to thinking about because + + + align:start position:0% +you're used to thinking about because +this involves a different type of an ion + + align:start position:0% +this involves a different type of an ion + + + align:start position:0% +this involves a different type of an ion +channel and it's called a voltage-gated + + align:start position:0% + + + + align:start position:0% + +and I'll breve eh + + align:start position:0% +and I'll breve eh + + + align:start position:0% +and I'll breve eh +voltage-gated just VG and in this case + + align:start position:0% +voltage-gated just VG and in this case + + + align:start position:0% +voltage-gated just VG and in this case +it'll be a sodium channel okay so what's + + align:start position:0% +it'll be a sodium channel okay so what's + + + align:start position:0% +it'll be a sodium channel okay so what's +a voltage-gated sodium channel this is a + + align:start position:0% +a voltage-gated sodium channel this is a + + + align:start position:0% +a voltage-gated sodium channel this is a +voltage-gated sodium channel here and + + align:start position:0% +voltage-gated sodium channel here and + + + align:start position:0% +voltage-gated sodium channel here and +you can see in the resting state of the + + align:start position:0% +you can see in the resting state of the + + + align:start position:0% +you can see in the resting state of the +cell this channel is closed and it's + + align:start position:0% +cell this channel is closed and it's + + + align:start position:0% +cell this channel is closed and it's +closed because of this red rod structure + + align:start position:0% +closed because of this red rod structure + + + align:start position:0% +closed because of this red rod structure +that's positively charged + + align:start position:0% +that's positively charged + + + align:start position:0% +that's positively charged +that's a positively charged alpha helix + + align:start position:0% +that's a positively charged alpha helix + + + align:start position:0% +that's a positively charged alpha helix +that is a part of this protein is and is + + align:start position:0% +that is a part of this protein is and is + + + align:start position:0% +that is a part of this protein is and is +embedded in the membrane but this alpha + + align:start position:0% +embedded in the membrane but this alpha + + + align:start position:0% +embedded in the membrane but this alpha +helix is is positioned down towards the + + align:start position:0% +helix is is positioned down towards the + + + align:start position:0% +helix is is positioned down towards the +cytoplasm because it's positively + + align:start position:0% +cytoplasm because it's positively + + + align:start position:0% +cytoplasm because it's positively +charged and the cytosolic face of the + + align:start position:0% +charged and the cytosolic face of the + + + align:start position:0% +charged and the cytosolic face of the +plasma membrane is negatively charged + + align:start position:0% +plasma membrane is negatively charged + + + align:start position:0% +plasma membrane is negatively charged +okay and the confirmation of this + + align:start position:0% +okay and the confirmation of this + + + align:start position:0% +okay and the confirmation of this +protein then depends on the charge + + align:start position:0% +protein then depends on the charge + + + align:start position:0% +protein then depends on the charge +across this membrane because when + + align:start position:0% +across this membrane because when + + + align:start position:0% +across this membrane because when +there's depolarization that shifts the + + align:start position:0% +there's depolarization that shifts the + + + align:start position:0% +there's depolarization that shifts the +position of this alpha helix such that + + align:start position:0% +position of this alpha helix such that + + + align:start position:0% +position of this alpha helix such that +now it shifts up towards the exterior + + align:start position:0% +now it shifts up towards the exterior + + + align:start position:0% +now it shifts up towards the exterior +face of the plasma membrane and that + + align:start position:0% +face of the plasma membrane and that + + + align:start position:0% +face of the plasma membrane and that +opens the channel which lets sodium ions + + align:start position:0% +opens the channel which lets sodium ions + + + align:start position:0% +opens the channel which lets sodium ions +rush in okay okay again sodium ions here + + align:start position:0% +rush in okay okay again sodium ions here + + + align:start position:0% +rush in okay okay again sodium ions here +they're always rushing downstream + + align:start position:0% +they're always rushing downstream + + + align:start position:0% +they're always rushing downstream +they're on their concentration gradient + + align:start position:0% +they're on their concentration gradient + + + align:start position:0% +they're on their concentration gradient +okay so in this case whether or not this + + align:start position:0% +okay so in this case whether or not this + + + align:start position:0% +okay so in this case whether or not this +channel is open or closed depends not on + + align:start position:0% +channel is open or closed depends not on + + + align:start position:0% +channel is open or closed depends not on +the presence of a ligand but on the + + align:start position:0% +the presence of a ligand but on the + + + align:start position:0% +the presence of a ligand but on the +membrane potential across the plasma + + align:start position:0% +membrane potential across the plasma + + + align:start position:0% +membrane potential across the plasma +membrane okay so these voltage-gated + + align:start position:0% +membrane okay so these voltage-gated + + + align:start position:0% +membrane okay so these voltage-gated +sodium channels they're opened + + align:start position:0% +sodium channels they're opened + + + align:start position:0% +sodium channels they're opened +by depolarization okay and then the + + align:start position:0% +by depolarization okay and then the + + + align:start position:0% +by depolarization okay and then the +question becomes if you open these + + align:start position:0% +question becomes if you open these + + + align:start position:0% +question becomes if you open these +channels at the very end of the neuron + + align:start position:0% +channels at the very end of the neuron + + + align:start position:0% +channels at the very end of the neuron +how do you get it such that this + + align:start position:0% +how do you get it such that this + + + align:start position:0% +how do you get it such that this +electrical signal moves uni-directional + + align:start position:0% +electrical signal moves uni-directional + + + align:start position:0% +electrical signal moves uni-directional +II along the neuron okay so what leads + + align:start position:0% +II along the neuron okay so what leads + + + align:start position:0% +II along the neuron okay so what leads +to you need directionality + + align:start position:0% + + + + align:start position:0% + +okay who's been to a sporting event + + align:start position:0% +okay who's been to a sporting event + + + align:start position:0% +okay who's been to a sporting event +light lately okay good you guys know the + + align:start position:0% +light lately okay good you guys know the + + + align:start position:0% +light lately okay good you guys know the +wave okay so we're gonna do the wave + + align:start position:0% +wave okay so we're gonna do the wave + + + align:start position:0% +wave okay so we're gonna do the wave +once you stand up you're gonna be tired + + align:start position:0% +once you stand up you're gonna be tired + + + align:start position:0% +once you stand up you're gonna be tired +and you're gonna have to sit down for a + + align:start position:0% +and you're gonna have to sit down for a + + + align:start position:0% +and you're gonna have to sit down for a +while okay I'm going to be a ligand volt + + align:start position:0% +while okay I'm going to be a ligand volt + + + align:start position:0% +while okay I'm going to be a ligand volt +I'm the ligand gated sodium channel so + + align:start position:0% +I'm the ligand gated sodium channel so + + + align:start position:0% +I'm the ligand gated sodium channel so +I'm gonna start things off okay you + + align:start position:0% +I'm gonna start things off okay you + + + align:start position:0% +I'm gonna start things off okay you +ready + + align:start position:0% +ready + + + align:start position:0% +ready +alright here we go + + align:start position:0% + + + + align:start position:0% + +okay that's basically an action + + align:start position:0% +okay that's basically an action + + + align:start position:0% +okay that's basically an action +potential okay so the way that this + + align:start position:0% +potential okay so the way that this + + + align:start position:0% +potential okay so the way that this +happened that this was uni-directional + + align:start position:0% +happened that this was uni-directional + + + align:start position:0% +happened that this was uni-directional +right is once you once you stood up and + + align:start position:0% +right is once you once you stood up and + + + align:start position:0% +right is once you once you stood up and +did the wave right you then sat down and + + align:start position:0% +did the wave right you then sat down and + + + align:start position:0% +did the wave right you then sat down and +you stopped doing anything okay + + align:start position:0% +you stopped doing anything okay + + + align:start position:0% +you stopped doing anything okay +and so these voltage-gated sodium + + align:start position:0% +and so these voltage-gated sodium + + + align:start position:0% +and so these voltage-gated sodium +channels have a similar property okay if + + align:start position:0% +channels have a similar property okay if + + + align:start position:0% +channels have a similar property okay if +we look at the next step in this the + + align:start position:0% +we look at the next step in this the + + + align:start position:0% +we look at the next step in this the +sodium channel is opened by + + align:start position:0% +sodium channel is opened by + + + align:start position:0% +sodium channel is opened by +depolarization and you see there's this + + align:start position:0% +depolarization and you see there's this + + + align:start position:0% +depolarization and you see there's this +ball of chain segment of the protein + + align:start position:0% +ball of chain segment of the protein + + + align:start position:0% +ball of chain segment of the protein +whether you see that yellow ball and + + align:start position:0% +whether you see that yellow ball and + + + align:start position:0% +whether you see that yellow ball and +once the sodium channel opens after + + align:start position:0% +once the sodium channel opens after + + + align:start position:0% +once the sodium channel opens after +about a millisecond that ball sticks in + + align:start position:0% +about a millisecond that ball sticks in + + + align:start position:0% +about a millisecond that ball sticks in +the channel pore and blocks it okay so + + align:start position:0% +the channel pore and blocks it okay so + + + align:start position:0% +the channel pore and blocks it okay so +these sodium channels open to let in + + align:start position:0% +these sodium channels open to let in + + + align:start position:0% +these sodium channels open to let in +sodium ions but then they're immediately + + align:start position:0% +sodium ions but then they're immediately + + + align:start position:0% +sodium ions but then they're immediately +inactivated after about a millisecond + + align:start position:0% +inactivated after about a millisecond + + + align:start position:0% +inactivated after about a millisecond +okay and so that enables uni-directional + + align:start position:0% +okay and so that enables uni-directional + + + align:start position:0% +okay and so that enables uni-directional +'ti okay so this is what I'll call + + align:start position:0% +'ti okay so this is what I'll call + + + align:start position:0% +'ti okay so this is what I'll call +voltage-gated sodium channel + + align:start position:0% +voltage-gated sodium channel + + + align:start position:0% +voltage-gated sodium channel +inactivation okay and how this promotes + + align:start position:0% +inactivation okay and how this promotes + + + align:start position:0% +inactivation okay and how this promotes +a travelling wave of depolarization is + + align:start position:0% +a travelling wave of depolarization is + + + align:start position:0% +a travelling wave of depolarization is +that if we consider an action potential + + align:start position:0% +that if we consider an action potential + + + align:start position:0% +that if we consider an action potential +moving along this axon from left to + + align:start position:0% +moving along this axon from left to + + + align:start position:0% +moving along this axon from left to +right and if the sodium channels in the + + align:start position:0% +right and if the sodium channels in the + + + align:start position:0% +right and if the sodium channels in the +green zone are currently open it came + + align:start position:0% +green zone are currently open it came + + + align:start position:0% +green zone are currently open it came +from the left which means that all the + + align:start position:0% +from the left which means that all the + + + align:start position:0% +from the left which means that all the +sodium channels to the left of this + + align:start position:0% +sodium channels to the left of this + + + align:start position:0% +sodium channels to the left of this +green zone are going to be inactivated + + align:start position:0% +green zone are going to be inactivated + + + align:start position:0% +green zone are going to be inactivated +okay so because they're inactivated here + + align:start position:0% +okay so because they're inactivated here + + + align:start position:0% +okay so because they're inactivated here +there won't be further deep polarization + + align:start position:0% +there won't be further deep polarization + + + align:start position:0% +there won't be further deep polarization +going to the left but depolarization + + align:start position:0% +going to the left but depolarization + + + align:start position:0% +going to the left but depolarization +will have to move to the right and you + + align:start position:0% +will have to move to the right and you + + + align:start position:0% +will have to move to the right and you +basically get this traveling wave and it + + align:start position:0% +basically get this traveling wave and it + + + align:start position:0% +basically get this traveling wave and it +goes one direction because if it came + + align:start position:0% +goes one direction because if it came + + + align:start position:0% +goes one direction because if it came +from somewhere which it always does then + + align:start position:0% +from somewhere which it always does then + + + align:start position:0% +from somewhere which it always does then +where it just was coming from all those + + align:start position:0% +where it just was coming from all those + + + align:start position:0% +where it just was coming from all those +sodium channels the voltage-gated sodium + + align:start position:0% +sodium channels the voltage-gated sodium + + + align:start position:0% +sodium channels the voltage-gated sodium +channels are going to be closed okay so + + align:start position:0% +channels are going to be closed okay so + + + align:start position:0% +channels are going to be closed okay so +this allows it to move in a + + align:start position:0% +this allows it to move in a + + + align:start position:0% +this allows it to move in a +single direction along the neuron also + + align:start position:0% +single direction along the neuron also + + + align:start position:0% +single direction along the neuron also +once the action potential gets to the + + align:start position:0% +once the action potential gets to the + + + align:start position:0% +once the action potential gets to the +end of the neuron it doesn't reflect + + align:start position:0% +end of the neuron it doesn't reflect + + + align:start position:0% +end of the neuron it doesn't reflect +back the other way in the neuron this + + align:start position:0% +back the other way in the neuron this + + + align:start position:0% +back the other way in the neuron this +can only go one direction okay so this + + align:start position:0% +can only go one direction okay so this + + + align:start position:0% +can only go one direction okay so this +provides you need directionality okay so + + align:start position:0% +provides you need directionality okay so + + + align:start position:0% +provides you need directionality okay so +it's this inactive or refractory period + + align:start position:0% +it's this inactive or refractory period + + + align:start position:0% +it's this inactive or refractory period +of the voltage-gated sodium channel + + align:start position:0% +of the voltage-gated sodium channel + + + align:start position:0% +of the voltage-gated sodium channel +which prevents the action potential from + + align:start position:0% +which prevents the action potential from + + + align:start position:0% +which prevents the action potential from +moving backwards okay now if you look at + + align:start position:0% +moving backwards okay now if you look at + + + align:start position:0% +moving backwards okay now if you look at +these action potentials in this cell you + + align:start position:0% +these action potentials in this cell you + + + align:start position:0% +these action potentials in this cell you +see that they happen but you don't just + + align:start position:0% +see that they happen but you don't just + + + align:start position:0% +see that they happen but you don't just +depolarize and stay depolarized the cell + + align:start position:0% +depolarize and stay depolarized the cell + + + align:start position:0% +depolarize and stay depolarized the cell +depolarizes and then repolarizes very + + align:start position:0% +depolarizes and then repolarizes very + + + align:start position:0% +depolarizes and then repolarizes very +rapidly + + align:start position:0% +rapidly + + + align:start position:0% +rapidly +okay so there's an oscillation okay so + + align:start position:0% +okay so there's an oscillation okay so + + + align:start position:0% +okay so there's an oscillation okay so +there has to be some way to terminate + + align:start position:0% +there has to be some way to terminate + + + align:start position:0% +there has to be some way to terminate +the action potential so there's a t + + align:start position:0% +the action potential so there's a t + + + align:start position:0% +the action potential so there's a t +termination or repolarization of the + + align:start position:0% +termination or repolarization of the + + + align:start position:0% +termination or repolarization of the +cell so there has to be a way for this + + align:start position:0% +cell so there has to be a way for this + + + align:start position:0% +cell so there has to be a way for this +nerve cell to rapidly restore membrane + + align:start position:0% +nerve cell to rapidly restore membrane + + + align:start position:0% +nerve cell to rapidly restore membrane +potential and I want you to think for + + align:start position:0% +potential and I want you to think for + + + align:start position:0% +potential and I want you to think for +just a couple seconds about what type of + + align:start position:0% +just a couple seconds about what type of + + + align:start position:0% +just a couple seconds about what type of +channel will might you open to + + align:start position:0% +channel will might you open to + + + align:start position:0% +channel will might you open to +reestablish this polarity what ion do + + align:start position:0% +reestablish this polarity what ion do + + + align:start position:0% +reestablish this polarity what ion do +you need to flow from where to where in + + align:start position:0% +you need to flow from where to where in + + + align:start position:0% +you need to flow from where to where in +order to get a net negative charge on + + align:start position:0% +order to get a net negative charge on + + + align:start position:0% +order to get a net negative charge on +the inside who don't + + align:start position:0% +the inside who don't + + + align:start position:0% +the inside who don't +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +okay you could pump the sodium ions out + + align:start position:0% +okay you could pump the sodium ions out + + + align:start position:0% +okay you could pump the sodium ions out +and that's totally accurate so that's + + align:start position:0% +and that's totally accurate so that's + + + align:start position:0% +and that's totally accurate so that's +going to require moving sodium ions up a + + align:start position:0% +going to require moving sodium ions up a + + + align:start position:0% +going to require moving sodium ions up a +concentration gradient which is going to + + align:start position:0% +concentration gradient which is going to + + + align:start position:0% +concentration gradient which is going to +take energy and is going to be slow so + + align:start position:0% +take energy and is going to be slow so + + + align:start position:0% +take energy and is going to be slow so +is there another option we could take + + align:start position:0% +is there another option we could take + + + align:start position:0% +is there another option we could take +advantage of here to repolarize Rachel + + align:start position:0% + + + + align:start position:0% + +so Rachel is suggested to moving the + + align:start position:0% +so Rachel is suggested to moving the + + + align:start position:0% +so Rachel is suggested to moving the +potassium ions to the outside which is + + align:start position:0% +potassium ions to the outside which is + + + align:start position:0% +potassium ions to the outside which is +how this is done + + align:start position:0% +how this is done + + + align:start position:0% +how this is done +so remember potassium is high on the in + + align:start position:0% +so remember potassium is high on the in + + + align:start position:0% +so remember potassium is high on the in +the cytoplasm low on the exo plasm and + + align:start position:0% +the cytoplasm low on the exo plasm and + + + align:start position:0% +the cytoplasm low on the exo plasm and +therefore if you have a voltage-gated + + align:start position:0% +therefore if you have a voltage-gated + + + align:start position:0% +therefore if you have a voltage-gated +potassium channel that's going to cause + + align:start position:0% +potassium channel that's going to cause + + + align:start position:0% +potassium channel that's going to cause +a rush of positive ions out of the cell + + align:start position:0% +a rush of positive ions out of the cell + + + align:start position:0% +a rush of positive ions out of the cell +and that will be able to restore the net + + align:start position:0% +and that will be able to restore the net + + + align:start position:0% +and that will be able to restore the net +negative potential on the inside of the + + align:start position:0% +negative potential on the inside of the + + + align:start position:0% +negative potential on the inside of the +cell okay so this termination or + + align:start position:0% +cell okay so this termination or + + + align:start position:0% +cell okay so this termination or +repolarization Leeds is the result of + + align:start position:0% +repolarization Leeds is the result of + + + align:start position:0% +repolarization Leeds is the result of +the opening of voltage-gated in this + + align:start position:0% +the opening of voltage-gated in this + + + align:start position:0% +the opening of voltage-gated in this +case not sodium channels but potassium + + align:start position:0% +case not sodium channels but potassium + + + align:start position:0% +case not sodium channels but potassium +channels when do you think these have to + + align:start position:0% +channels when do you think these have to + + + align:start position:0% +channels when do you think these have to +open relative to the sodium channel + + align:start position:0% + + + + align:start position:0% + +should they open right with the sodium + + align:start position:0% +should they open right with the sodium + + + align:start position:0% +should they open right with the sodium +channel + + align:start position:0% +channel + + + align:start position:0% +channel +karmen shaking your head no do you want + + align:start position:0% +karmen shaking your head no do you want + + + align:start position:0% +karmen shaking your head no do you want +to explain your logic + + align:start position:0% + + + + align:start position:0% + +exactly mm-hmm so a Carmen said is if + + align:start position:0% +exactly mm-hmm so a Carmen said is if + + + align:start position:0% +exactly mm-hmm so a Carmen said is if +they open simultaneously you have sodium + + align:start position:0% +they open simultaneously you have sodium + + + align:start position:0% +they open simultaneously you have sodium +flowing in your potassium flowing out + + align:start position:0% +flowing in your potassium flowing out + + + align:start position:0% +flowing in your potassium flowing out +and that's not going to necessarily + + align:start position:0% +and that's not going to necessarily + + + align:start position:0% +and that's not going to necessarily +change their charge okay so when would + + align:start position:0% +change their charge okay so when would + + + align:start position:0% +change their charge okay so when would +these have to open relative to sodium + + align:start position:0% +these have to open relative to sodium + + + align:start position:0% +these have to open relative to sodium +channels yeah Carmen so after it's + + align:start position:0% +channels yeah Carmen so after it's + + + align:start position:0% +channels yeah Carmen so after it's +depolarized yeah so this has to be + + align:start position:0% +depolarized yeah so this has to be + + + align:start position:0% +depolarized yeah so this has to be +delayed relative to the sodium channels + + align:start position:0% +delayed relative to the sodium channels + + + align:start position:0% +delayed relative to the sodium channels +okay so this has to be delayed relative + + align:start position:0% +okay so this has to be delayed relative + + + align:start position:0% +okay so this has to be delayed relative +to the voltage-gated sodium channels + + align:start position:0% + + + + align:start position:0% + +right because if you're thinking about + + align:start position:0% +right because if you're thinking about + + + align:start position:0% +right because if you're thinking about +this traveling wave of depolarization + + align:start position:0% +this traveling wave of depolarization + + + align:start position:0% +this traveling wave of depolarization +the depolarization is going to be high + + align:start position:0% +the depolarization is going to be high + + + align:start position:0% +the depolarization is going to be high +where the sodium channels are only + + align:start position:0% +where the sodium channels are only + + + align:start position:0% +where the sodium channels are only +entering and then following that you + + align:start position:0% +entering and then following that you + + + align:start position:0% +entering and then following that you +would have potassium ions getting pumped + + align:start position:0% +would have potassium ions getting pumped + + + align:start position:0% +would have potassium ions getting pumped +out and basically repolarizing the cell + + align:start position:0% +out and basically repolarizing the cell + + + align:start position:0% +out and basically repolarizing the cell +okay everyone see how you sort of you + + align:start position:0% +okay everyone see how you sort of you + + + align:start position:0% +okay everyone see how you sort of you +get depolarization with sodium rushing + + align:start position:0% +get depolarization with sodium rushing + + + align:start position:0% +get depolarization with sodium rushing +in and then after that you repolarize + + align:start position:0% +in and then after that you repolarize + + + align:start position:0% +in and then after that you repolarize +with the potassium getting pumped out + + align:start position:0% +with the potassium getting pumped out + + + align:start position:0% +with the potassium getting pumped out +right so here you have a spike and you + + align:start position:0% +right so here you have a spike and you + + + align:start position:0% +right so here you have a spike and you +complete the cycle it can even get + + align:start position:0% +complete the cycle it can even get + + + align:start position:0% +complete the cycle it can even get +hyperpolarized where it gets even more + + align:start position:0% +hyperpolarized where it gets even more + + + align:start position:0% +hyperpolarized where it gets even more +negative than it normally does and then + + align:start position:0% +negative than it normally does and then + + + align:start position:0% +negative than it normally does and then +it eventually gets back to this resting + + align:start position:0% +it eventually gets back to this resting + + + align:start position:0% +it eventually gets back to this resting +potential of around negative 60 or + + align:start position:0% +potential of around negative 60 or + + + align:start position:0% +potential of around negative 60 or +negative 70 millivolts + + align:start position:0% + + + + align:start position:0% + +okay so this has to happen fast and I + + align:start position:0% +okay so this has to happen fast and I + + + align:start position:0% +okay so this has to happen fast and I +want to tell you about one process or + + align:start position:0% +want to tell you about one process or + + + align:start position:0% +want to tell you about one process or +property of neurons and another helpful + + align:start position:0% +property of neurons and another helpful + + + align:start position:0% +property of neurons and another helpful +cell that enables this to go extremely + + align:start position:0% +cell that enables this to go extremely + + + align:start position:0% +cell that enables this to go extremely +fast and that is that there are these + + align:start position:0% +fast and that is that there are these + + + align:start position:0% +fast and that is that there are these +glial cells in your body and your brain + + align:start position:0% +glial cells in your body and your brain + + + align:start position:0% +glial cells in your body and your brain +that wrap around the axons of the + + align:start position:0% +that wrap around the axons of the + + + align:start position:0% +that wrap around the axons of the +neurons and basically function like + + align:start position:0% +neurons and basically function like + + + align:start position:0% +neurons and basically function like +electrical tape for neurons okay so they + + align:start position:0% +electrical tape for neurons okay so they + + + align:start position:0% +electrical tape for neurons okay so they +are these there's electrical insulation + + align:start position:0% + + + + align:start position:0% + +around the axons of these neurons and + + align:start position:0% +around the axons of these neurons and + + + align:start position:0% +around the axons of these neurons and +this is provided by another specialized + + align:start position:0% +this is provided by another specialized + + + align:start position:0% +this is provided by another specialized +cell type called a glial cell so this is + + align:start position:0% +cell type called a glial cell so this is + + + align:start position:0% +cell type called a glial cell so this is +by a glial cell okay and here are two + + align:start position:0% +by a glial cell okay and here are two + + + align:start position:0% +by a glial cell okay and here are two +examples of glial cells there are Lego + + align:start position:0% +examples of glial cells there are Lego + + + align:start position:0% +examples of glial cells there are Lego +oligodendrocytes and you can see how + + align:start position:0% +oligodendrocytes and you can see how + + + align:start position:0% +oligodendrocytes and you can see how +this cells extending processes that wrap + + align:start position:0% +this cells extending processes that wrap + + + align:start position:0% +this cells extending processes that wrap +around the axons of these two neurons + + align:start position:0% +around the axons of these two neurons + + + align:start position:0% +around the axons of these two neurons +here's a Schwann cell over here which + + align:start position:0% +here's a Schwann cell over here which + + + align:start position:0% +here's a Schwann cell over here which +again wraps around the axon and these + + align:start position:0% +again wraps around the axon and these + + + align:start position:0% +again wraps around the axon and these +cells basically form what's called a + + align:start position:0% +cells basically form what's called a + + + align:start position:0% +cells basically form what's called a +myelin sheath so they form a myelin + + align:start position:0% +myelin sheath so they form a myelin + + + align:start position:0% +myelin sheath so they form a myelin +sheath around the axons and that + + align:start position:0% +sheath around the axons and that + + + align:start position:0% +sheath around the axons and that +insulates the plasma membrane of the + + align:start position:0% +insulates the plasma membrane of the + + + align:start position:0% +insulates the plasma membrane of the +axon such that so here's a an axon you + + align:start position:0% +axon such that so here's a an axon you + + + align:start position:0% +axon such that so here's a an axon you +have glial cells or wrapped around and + + align:start position:0% +have glial cells or wrapped around and + + + align:start position:0% +have glial cells or wrapped around and +it sort of forms like beads on a string + + align:start position:0% +it sort of forms like beads on a string + + + align:start position:0% +it sort of forms like beads on a string +and so there are these gaps between the + + align:start position:0% +and so there are these gaps between the + + + align:start position:0% +and so there are these gaps between the +myelin sheath that are known as the note + + align:start position:0% +myelin sheath that are known as the note + + + align:start position:0% +myelin sheath that are known as the note +nodes of ranvier okay so there are these + + align:start position:0% +nodes of ranvier okay so there are these + + + align:start position:0% +nodes of ranvier okay so there are these +nodes of ranvier + + align:start position:0% + + + + align:start position:0% + +which are gaps in the myelin sheath and + + align:start position:0% +which are gaps in the myelin sheath and + + + align:start position:0% +which are gaps in the myelin sheath and +these nodes perform an important + + align:start position:0% +these nodes perform an important + + + align:start position:0% +these nodes perform an important +function for the neuron because where + + align:start position:0% +function for the neuron because where + + + align:start position:0% +function for the neuron because where +the axon is wrapped the the membrane is + + align:start position:0% +the axon is wrapped the the membrane is + + + align:start position:0% +the axon is wrapped the the membrane is +electrically insulated and so the sodium + + align:start position:0% +electrically insulated and so the sodium + + + align:start position:0% +electrically insulated and so the sodium +ions are the sodium channels and + + align:start position:0% +ions are the sodium channels and + + + align:start position:0% +ions are the sodium channels and +potassium channels the voltage-gated + + align:start position:0% +potassium channels the voltage-gated + + + align:start position:0% +potassium channels the voltage-gated +ones localized to these nodes and when + + align:start position:0% +ones localized to these nodes and when + + + align:start position:0% +ones localized to these nodes and when +the action potential is traveling along + + align:start position:0% +the action potential is traveling along + + + align:start position:0% +the action potential is traveling along +the axon because these regions where the + + align:start position:0% +the axon because these regions where the + + + align:start position:0% +the axon because these regions where the +myelin sheath is are electrically + + align:start position:0% +myelin sheath is are electrically + + + align:start position:0% +myelin sheath is are electrically +insulated the axon potential doesn't + + align:start position:0% +insulated the axon potential doesn't + + + align:start position:0% +insulated the axon potential doesn't +just move continuously but jumps from + + align:start position:0% +just move continuously but jumps from + + + align:start position:0% +just move continuously but jumps from +node to node such that you're just + + align:start position:0% +node to node such that you're just + + + align:start position:0% +node to node such that you're just +opening the sodium channels at these + + align:start position:0% +opening the sodium channels at these + + + align:start position:0% +opening the sodium channels at these +nodes and that allows the action + + align:start position:0% +nodes and that allows the action + + + align:start position:0% +nodes and that allows the action +potential to travel about a hundredfold + + align:start position:0% +potential to travel about a hundredfold + + + align:start position:0% +potential to travel about a hundredfold +faster along the axon and that's what + + align:start position:0% +faster along the axon and that's what + + + align:start position:0% +faster along the axon and that's what +allows your neurons to transmit these + + align:start position:0% +allows your neurons to transmit these + + + align:start position:0% +allows your neurons to transmit these +electrical signals from the base of your + + align:start position:0% +electrical signals from the base of your + + + align:start position:0% +electrical signals from the base of your +spine to your foot so rapidly okay so + + align:start position:0% +spine to your foot so rapidly okay so + + + align:start position:0% +spine to your foot so rapidly okay so +you get an increase in speed because the + + align:start position:0% +you get an increase in speed because the + + + align:start position:0% +you get an increase in speed because the +action potential is jumping from node to + + align:start position:0% +action potential is jumping from node to + + + align:start position:0% +action potential is jumping from node to +node and one important reason to bring + + align:start position:0% +node and one important reason to bring + + + align:start position:0% +node and one important reason to bring +this up is because there is a an + + align:start position:0% +this up is because there is a an + + + align:start position:0% +this up is because there is a an +important human disease that affects the + + align:start position:0% +important human disease that affects the + + + align:start position:0% +important human disease that affects the +electrical insulation in the myelin + + align:start position:0% +electrical insulation in the myelin + + + align:start position:0% +electrical insulation in the myelin +sheath here and that's multiple + + align:start position:0% +sheath here and that's multiple + + + align:start position:0% +sheath here and that's multiple +sclerosis so we're gonna unpack multiple + + align:start position:0% +sclerosis so we're gonna unpack multiple + + + align:start position:0% +sclerosis so we're gonna unpack multiple +sclerosis in a couple lectures this is + + align:start position:0% +sclerosis in a couple lectures this is + + + align:start position:0% +sclerosis in a couple lectures this is +an autoimmune disorder and so we're + + align:start position:0% +an autoimmune disorder and so we're + + + align:start position:0% +an autoimmune disorder and so we're +going to talk about immunity later in + + align:start position:0% +going to talk about immunity later in + + + align:start position:0% +going to talk about immunity later in +the semester and we'll talk about how + + align:start position:0% +the semester and we'll talk about how + + + align:start position:0% +the semester and we'll talk about how +that happens but for now I just want to + + align:start position:0% +that happens but for now I just want to + + + align:start position:0% +that happens but for now I just want to +point out that multiple sclerosis + + align:start position:0% +point out that multiple sclerosis + + + align:start position:0% +point out that multiple sclerosis +happens when the immune system attacks + + align:start position:0% +happens when the immune system attacks + + + align:start position:0% +happens when the immune system attacks +this myelin sheath so in multiple + + align:start position:0% +this myelin sheath so in multiple + + + align:start position:0% +this myelin sheath so in multiple +sclerosis the myelin sheath is damaged + + align:start position:0% + + + + align:start position:0% + +okay and if you damage this electrical + + align:start position:0% +okay and if you damage this electrical + + + align:start position:0% +okay and if you damage this electrical +insulation + + align:start position:0% +insulation + + + align:start position:0% +insulation +you greatly slow down these action + + align:start position:0% +you greatly slow down these action + + + align:start position:0% +you greatly slow down these action +potentials and that has a significant + + align:start position:0% +potentials and that has a significant + + + align:start position:0% +potentials and that has a significant +impact on nerve + + align:start position:0% +impact on nerve + + + align:start position:0% +impact on nerve +pulses in the brain and throughout the + + align:start position:0% +pulses in the brain and throughout the + + + align:start position:0% +pulses in the brain and throughout the +entire body and that's why multiple + + align:start position:0% +entire body and that's why multiple + + + align:start position:0% +entire body and that's why multiple +sclerosis is such a devastating disease + + align:start position:0% + + + + align:start position:0% + +all right I'm gonna start moving now to + + align:start position:0% +all right I'm gonna start moving now to + + + align:start position:0% +all right I'm gonna start moving now to +consider one more than one neuron so + + align:start position:0% +consider one more than one neuron so + + + align:start position:0% +consider one more than one neuron so +until now we've just talked about how an + + align:start position:0% +until now we've just talked about how an + + + align:start position:0% +until now we've just talked about how an +electrical signal is sent along the + + align:start position:0% +electrical signal is sent along the + + + align:start position:0% +electrical signal is sent along the +length of one cell and now we're gonna + + align:start position:0% +length of one cell and now we're gonna + + + align:start position:0% +length of one cell and now we're gonna +start thinking about multiple neurons + + align:start position:0% +start thinking about multiple neurons + + + align:start position:0% +start thinking about multiple neurons +and how they connect and how neurons + + align:start position:0% +and how they connect and how neurons + + + align:start position:0% +and how they connect and how neurons +integrate information from multiple + + align:start position:0% +integrate information from multiple + + + align:start position:0% +integrate information from multiple +other neurons to decide whether or not + + align:start position:0% +other neurons to decide whether or not + + + align:start position:0% +other neurons to decide whether or not +to send an action potential okay and so + + align:start position:0% +to send an action potential okay and so + + + align:start position:0% +to send an action potential okay and so +if we consider this connection right + + align:start position:0% +if we consider this connection right + + + align:start position:0% +if we consider this connection right +here there's a synapse right here here's + + align:start position:0% +here there's a synapse right here here's + + + align:start position:0% +here there's a synapse right here here's +a sending a cell that's sending + + align:start position:0% +a sending a cell that's sending + + + align:start position:0% +a sending a cell that's sending +information in the cell that is + + align:start position:0% +information in the cell that is + + + align:start position:0% +information in the cell that is +receiving that information when we're + + align:start position:0% +receiving that information when we're + + + align:start position:0% +receiving that information when we're +considering a synapse so if we consider + + align:start position:0% +considering a synapse so if we consider + + + align:start position:0% +considering a synapse so if we consider +a synapse there's a cell that is sending + + align:start position:0% +a synapse there's a cell that is sending + + + align:start position:0% +a synapse there's a cell that is sending +the signal which is called the pre + + align:start position:0% +the signal which is called the pre + + + align:start position:0% +the signal which is called the pre +synapse this is the sender cell and + + align:start position:0% +synapse this is the sender cell and + + + align:start position:0% +synapse this is the sender cell and +there's a postsynaptic cell okay but you + + align:start position:0% +there's a postsynaptic cell okay but you + + + align:start position:0% +there's a postsynaptic cell okay but you +can have more than one neuron sending a + + align:start position:0% +can have more than one neuron sending a + + + align:start position:0% +can have more than one neuron sending a +signal to a neuron at this at a given + + align:start position:0% +signal to a neuron at this at a given + + + align:start position:0% +signal to a neuron at this at a given +time + + align:start position:0% +time + + + align:start position:0% +time +right so here you have one neuron there + + align:start position:0% +right so here you have one neuron there + + + align:start position:0% +right so here you have one neuron there +it's sending a signal at this synapse + + align:start position:0% +it's sending a signal at this synapse + + + align:start position:0% +it's sending a signal at this synapse +but you might have another neuron + + align:start position:0% +but you might have another neuron + + + align:start position:0% +but you might have another neuron +sending a signal to a synapse on this + + align:start position:0% +sending a signal to a synapse on this + + + align:start position:0% +sending a signal to a synapse on this +part of the cell and you could have + + align:start position:0% +part of the cell and you could have + + + align:start position:0% +part of the cell and you could have +another signal coming in here and so + + align:start position:0% +another signal coming in here and so + + + align:start position:0% +another signal coming in here and so +this this neuron will then have to + + align:start position:0% +this this neuron will then have to + + + align:start position:0% +this this neuron will then have to +decide whether or not to fire an action + + align:start position:0% +decide whether or not to fire an action + + + align:start position:0% +decide whether or not to fire an action +potential down its axon okay and the way + + align:start position:0% +potential down its axon okay and the way + + + align:start position:0% +potential down its axon okay and the way +that the neuron decides this is to + + align:start position:0% +that the neuron decides this is to + + + align:start position:0% +that the neuron decides this is to +integrate the signals so there's a + + align:start position:0% +integrate the signals so there's a + + + align:start position:0% +integrate the signals so there's a +signal integration process and what's + + align:start position:0% +signal integration process and what's + + + align:start position:0% +signal integration process and what's +important for signal integration in a + + align:start position:0% +important for signal integration in a + + + align:start position:0% +important for signal integration in a +neuron is whether or not the cell body + + align:start position:0% +neuron is whether or not the cell body + + + align:start position:0% +neuron is whether or not the cell body +whether the voltage increases above a + + align:start position:0% +whether the voltage increases above a + + + align:start position:0% +whether the voltage increases above a +certain threshold potential so if the + + align:start position:0% +certain threshold potential so if the + + + align:start position:0% +certain threshold potential so if the +cell body doesn't increase if the + + align:start position:0% +cell body doesn't increase if the + + + align:start position:0% +cell body doesn't increase if the +voltage doesn't increase + + align:start position:0% +voltage doesn't increase + + + align:start position:0% +voltage doesn't increase +above this potential there will be no + + align:start position:0% +above this potential there will be no + + + align:start position:0% +above this potential there will be no +action potential fired but if the action + + align:start position:0% +action potential fired but if the action + + + align:start position:0% +action potential fired but if the action +if the voltage increases above the + + align:start position:0% +if the voltage increases above the + + + align:start position:0% +if the voltage increases above the +threshold potential then it fires the + + align:start position:0% +threshold potential then it fires the + + + align:start position:0% +threshold potential then it fires the +action potential and signals to a + + align:start position:0% +action potential and signals to a + + + align:start position:0% +action potential and signals to a +downstream neuron or muscle or another + + align:start position:0% +downstream neuron or muscle or another + + + align:start position:0% +downstream neuron or muscle or another +cell okay so here it is the threshold + + align:start position:0% +cell okay so here it is the threshold + + + align:start position:0% +cell okay so here it is the threshold +potential in the cell body that + + align:start position:0% +potential in the cell body that + + + align:start position:0% +potential in the cell body that +determines whether or not an action + + align:start position:0% +determines whether or not an action + + + align:start position:0% +determines whether or not an action +potential is sent down the axon okay and + + align:start position:0% +potential is sent down the axon okay and + + + align:start position:0% +potential is sent down the axon okay and +there are different types of signals + + align:start position:0% +there are different types of signals + + + align:start position:0% +there are different types of signals +that nerve cells can send so there are + + align:start position:0% +that nerve cells can send so there are + + + align:start position:0% +that nerve cells can send so there are +different types of signals signals can + + align:start position:0% +different types of signals signals can + + + align:start position:0% +different types of signals signals can +be excitatory meaning it deep will tend + + align:start position:0% +be excitatory meaning it deep will tend + + + align:start position:0% +be excitatory meaning it deep will tend +to depolarize the neuron so there are + + align:start position:0% +to depolarize the neuron so there are + + + align:start position:0% +to depolarize the neuron so there are +excitatory signals which results in + + align:start position:0% +excitatory signals which results in + + + align:start position:0% +excitatory signals which results in +depolarization for example with + + align:start position:0% +depolarization for example with + + + align:start position:0% +depolarization for example with +serotonin that opens a sodium channel + + align:start position:0% +serotonin that opens a sodium channel + + + align:start position:0% +serotonin that opens a sodium channel +and that results in depolarization so + + align:start position:0% +and that results in depolarization so + + + align:start position:0% +and that results in depolarization so +that's an excitatory signal but there + + align:start position:0% +that's an excitatory signal but there + + + align:start position:0% +that's an excitatory signal but there +are other types of signals that bind to + + align:start position:0% +are other types of signals that bind to + + + align:start position:0% +are other types of signals that bind to +different types of receptors that are + + align:start position:0% +different types of receptors that are + + + align:start position:0% +different types of receptors that are +inhibitory what might be a type of + + align:start position:0% +inhibitory what might be a type of + + + align:start position:0% +inhibitory what might be a type of +receptor that would inhibit this process + + align:start position:0% +receptor that would inhibit this process + + + align:start position:0% +receptor that would inhibit this process +of sending an action potential + + align:start position:0% + + + + align:start position:0% + +what might an inhibitory receptor be to + + align:start position:0% +what might an inhibitory receptor be to + + + align:start position:0% +what might an inhibitory receptor be to +make sure to lower the chance that this + + align:start position:0% +make sure to lower the chance that this + + + align:start position:0% +make sure to lower the chance that this +action potential will be fired + + align:start position:0% + + + + align:start position:0% + +what if I told you it's it's an ion + + align:start position:0% +what if I told you it's it's an ion + + + align:start position:0% +what if I told you it's it's an ion +channel what ion would you expect it + + align:start position:0% +channel what ion would you expect it + + + align:start position:0% +channel what ion would you expect it +might pass pseudo + + align:start position:0% +might pass pseudo + + + align:start position:0% +might pass pseudo +potassium Uno is exactly right right if + + align:start position:0% +potassium Uno is exactly right right if + + + align:start position:0% +potassium Uno is exactly right right if +you test if it passes potassium then + + align:start position:0% +you test if it passes potassium then + + + align:start position:0% +you test if it passes potassium then +it's gonna it's gonna make the inside + + align:start position:0% +it's gonna it's gonna make the inside + + + align:start position:0% +it's gonna it's gonna make the inside +more negative and that's what's known as + + align:start position:0% +more negative and that's what's known as + + + align:start position:0% +more negative and that's what's known as +hyperpolarization so receptors that + + align:start position:0% +hyperpolarization so receptors that + + + align:start position:0% +hyperpolarization so receptors that +result in hyperpolarization would have + + align:start position:0% +result in hyperpolarization would have + + + align:start position:0% +result in hyperpolarization would have +an inhibitory effect on this process + + align:start position:0% + + + + align:start position:0% + +okay right and remember if your + + align:start position:0% +okay right and remember if your + + + align:start position:0% +okay right and remember if your +hyperpolarizing then you're gonna you + + align:start position:0% +hyperpolarizing then you're gonna you + + + align:start position:0% +hyperpolarizing then you're gonna you +could cause this to actually go down and + + align:start position:0% +could cause this to actually go down and + + + align:start position:0% +could cause this to actually go down and +get even farther away from this + + align:start position:0% +get even farther away from this + + + align:start position:0% +get even farther away from this +threshold potential right and if you + + align:start position:0% +threshold potential right and if you + + + align:start position:0% +threshold potential right and if you +have an activating signal and an + + align:start position:0% +have an activating signal and an + + + align:start position:0% +have an activating signal and an +inhibitory signal they might cancel out + + align:start position:0% +inhibitory signal they might cancel out + + + align:start position:0% +inhibitory signal they might cancel out +because one will depolarize in the other + + align:start position:0% +because one will depolarize in the other + + + align:start position:0% +because one will depolarize in the other +will hyperpolarize so it's in this way + + align:start position:0% +will hyperpolarize so it's in this way + + + align:start position:0% +will hyperpolarize so it's in this way +and neuron is able to integrate signals + + align:start position:0% +and neuron is able to integrate signals + + + align:start position:0% +and neuron is able to integrate signals +coming from different neurons and that + + align:start position:0% +coming from different neurons and that + + + align:start position:0% +coming from different neurons and that +influences whether or not it will send + + align:start position:0% +influences whether or not it will send + + + align:start position:0% +influences whether or not it will send +the signal to a downstream a cell okay + + align:start position:0% +the signal to a downstream a cell okay + + + align:start position:0% +the signal to a downstream a cell okay +so now we're focusing on what is the + + align:start position:0% +so now we're focusing on what is the + + + align:start position:0% +so now we're focusing on what is the +communication between one neuron and + + align:start position:0% +communication between one neuron and + + + align:start position:0% +communication between one neuron and +another and this revolves around this + + align:start position:0% +another and this revolves around this + + + align:start position:0% +another and this revolves around this +thing that's called the synapse which is + + align:start position:0% +thing that's called the synapse which is + + + align:start position:0% +thing that's called the synapse which is +basically the gap between the axon + + align:start position:0% +basically the gap between the axon + + + align:start position:0% +basically the gap between the axon +terminal of one neuron and the dendrites + + align:start position:0% +terminal of one neuron and the dendrites + + + align:start position:0% +terminal of one neuron and the dendrites +of a postsynaptic neuron okay and so the + + align:start position:0% +of a postsynaptic neuron okay and so the + + + align:start position:0% +of a postsynaptic neuron okay and so the +way that multiple neurons communicate + + align:start position:0% +way that multiple neurons communicate + + + align:start position:0% +way that multiple neurons communicate +with each other are through a type of + + align:start position:0% +with each other are through a type of + + + align:start position:0% +with each other are through a type of +signal known as a neurotransmitter okay + + align:start position:0% +signal known as a neurotransmitter okay + + + align:start position:0% +signal known as a neurotransmitter okay +and this is what initiates the signal so + + align:start position:0% +and this is what initiates the signal so + + + align:start position:0% +and this is what initiates the signal so +there's a signal initiation process at + + align:start position:0% +there's a signal initiation process at + + + align:start position:0% +there's a signal initiation process at +the synapse initiation and then this + + align:start position:0% +the synapse initiation and then this + + + align:start position:0% +the synapse initiation and then this +involves the presynaptic neuron + + align:start position:0% +involves the presynaptic neuron + + + align:start position:0% +involves the presynaptic neuron +secreting a neurotransmitter so the + + align:start position:0% +secreting a neurotransmitter so the + + + align:start position:0% +secreting a neurotransmitter so the +signal in this case signals between + + align:start position:0% +signal in this case signals between + + + align:start position:0% +signal in this case signals between +neurons are called neurotransmitters and + + align:start position:0% +neurons are called neurotransmitters and + + + align:start position:0% +neurons are called neurotransmitters and +as you see on the slide these are + + align:start position:0% +as you see on the slide these are + + + align:start position:0% +as you see on the slide these are +examples of neurotransmitters they're + + align:start position:0% +examples of neurotransmitters they're + + + align:start position:0% +examples of neurotransmitters they're +often derived from amino acids and so + + align:start position:0% +often derived from amino acids and so + + + align:start position:0% +often derived from amino acids and so +there's small molecules they're not the + + align:start position:0% +there's small molecules they're not the + + + align:start position:0% +there's small molecules they're not the +proteins that you often see with + + align:start position:0% +proteins that you often see with + + + align:start position:0% +proteins that you often see with +receptor tyrosine kinase ligands this is + + align:start position:0% +receptor tyrosine kinase ligands this is + + + align:start position:0% +receptor tyrosine kinase ligands this is +a different class of signal + + align:start position:0% +a different class of signal + + + align:start position:0% +a different class of signal +so one example is serotonin and if you + + align:start position:0% +so one example is serotonin and if you + + + align:start position:0% +so one example is serotonin and if you +look up at those will find serotonin + + align:start position:0% +look up at those will find serotonin + + + align:start position:0% +look up at those will find serotonin +here there it is here you can see it's a + + align:start position:0% +here there it is here you can see it's a + + + align:start position:0% +here there it is here you can see it's a +derivative of tryptophan okay so it's a + + align:start position:0% +derivative of tryptophan okay so it's a + + + align:start position:0% +derivative of tryptophan okay so it's a +small molecule and it's able to bind to + + align:start position:0% +small molecule and it's able to bind to + + + align:start position:0% +small molecule and it's able to bind to +a receptor on the postsynaptic cell and + + align:start position:0% +a receptor on the postsynaptic cell and + + + align:start position:0% +a receptor on the postsynaptic cell and +induce depolarization okay and so + + align:start position:0% +induce depolarization okay and so + + + align:start position:0% +induce depolarization okay and so +neurons are the way that they + + align:start position:0% +neurons are the way that they + + + align:start position:0% +neurons are the way that they +communicate as neurons are a case of + + align:start position:0% +communicate as neurons are a case of + + + align:start position:0% +communicate as neurons are a case of +where luck favors the prepared + + align:start position:0% +where luck favors the prepared + + + align:start position:0% +where luck favors the prepared +neurons are totally prepared to send + + align:start position:0% +neurons are totally prepared to send + + + align:start position:0% +neurons are totally prepared to send +signals to each other they have + + align:start position:0% +signals to each other they have + + + align:start position:0% +signals to each other they have +everything ready to go when they get + + align:start position:0% +everything ready to go when they get + + + align:start position:0% +everything ready to go when they get +word from from upstream and they're + + align:start position:0% +word from from upstream and they're + + + align:start position:0% +word from from upstream and they're +ready to send signals to their next cell + + align:start position:0% +ready to send signals to their next cell + + + align:start position:0% +ready to send signals to their next cell +okay and that's because if we look at + + align:start position:0% +okay and that's because if we look at + + + align:start position:0% +okay and that's because if we look at +the synapse prior to an action potential + + align:start position:0% +the synapse prior to an action potential + + + align:start position:0% +the synapse prior to an action potential +everything is ready to go + + align:start position:0% +everything is ready to go + + + align:start position:0% +everything is ready to go +the cell has neurotransmitter and it's + + align:start position:0% +the cell has neurotransmitter and it's + + + align:start position:0% +the cell has neurotransmitter and it's +packaged in these vesicles and it's + + align:start position:0% +packaged in these vesicles and it's + + + align:start position:0% +packaged in these vesicles and it's +tethered to the plasma membrane ready to + + align:start position:0% +tethered to the plasma membrane ready to + + + align:start position:0% +tethered to the plasma membrane ready to +be released + + align:start position:0% +be released + + + align:start position:0% +be released +okay so prior to the action potential + + align:start position:0% +okay so prior to the action potential + + + align:start position:0% +okay so prior to the action potential +there are vesicles filled with + + align:start position:0% +there are vesicles filled with + + + align:start position:0% +there are vesicles filled with +neurotransmitter that are docked at the + + align:start position:0% +neurotransmitter that are docked at the + + + align:start position:0% +neurotransmitter that are docked at the +plasma membrane I abbreviate plasma + + align:start position:0% +plasma membrane I abbreviate plasma + + + align:start position:0% +plasma membrane I abbreviate plasma +membrane p.m. just so I don't have to + + align:start position:0% +membrane p.m. just so I don't have to + + + align:start position:0% +membrane p.m. just so I don't have to +write it out okay so these contain + + align:start position:0% +write it out okay so these contain + + + align:start position:0% +write it out okay so these contain +neurotransmitter right but you see in + + align:start position:0% +neurotransmitter right but you see in + + + align:start position:0% +neurotransmitter right but you see in +this dock vesicle the neurotransmitter + + align:start position:0% +this dock vesicle the neurotransmitter + + + align:start position:0% +this dock vesicle the neurotransmitter +is in red and it can't get out if that + + align:start position:0% +is in red and it can't get out if that + + + align:start position:0% +is in red and it can't get out if that +vesicle does not fuse with the plasma + + align:start position:0% +vesicle does not fuse with the plasma + + + align:start position:0% +vesicle does not fuse with the plasma +membrane okay so these contain + + align:start position:0% +membrane okay so these contain + + + align:start position:0% +membrane okay so these contain +neurotransmitter + + align:start position:0% + + + + align:start position:0% + +but at this point the vesicles have + + align:start position:0% +but at this point the vesicles have + + + align:start position:0% +but at this point the vesicles have +infused but the vesicles not fused okay + + align:start position:0% +infused but the vesicles not fused okay + + + align:start position:0% +infused but the vesicles not fused okay +when should they fuse in this system of + + align:start position:0% +when should they fuse in this system of + + + align:start position:0% +when should they fuse in this system of +neurons signaling to each other when + + align:start position:0% +neurons signaling to each other when + + + align:start position:0% +neurons signaling to each other when +should these the vesicle fused with the + + align:start position:0% +should these the vesicle fused with the + + + align:start position:0% +should these the vesicle fused with the +plasma membrane + + align:start position:0% +plasma membrane + + + align:start position:0% +plasma membrane +what should trigger the fusion process + + align:start position:0% +what should trigger the fusion process + + + align:start position:0% +what should trigger the fusion process +yes miles yeah so miles is exactly right + + align:start position:0% +yes miles yeah so miles is exactly right + + + align:start position:0% +yes miles yeah so miles is exactly right +right if we consider my diagram here + + align:start position:0% +right if we consider my diagram here + + + align:start position:0% +right if we consider my diagram here +right there's an action potential + + align:start position:0% +right there's an action potential + + + align:start position:0% +right there's an action potential +traveling along this axon when it gets + + align:start position:0% +traveling along this axon when it gets + + + align:start position:0% +traveling along this axon when it gets +to the axon terminus that should be that + + align:start position:0% +to the axon terminus that should be that + + + align:start position:0% +to the axon terminus that should be that +fits the signal for these vesicles + + align:start position:0% +fits the signal for these vesicles + + + align:start position:0% +fits the signal for these vesicles +diffuse to the plasma membrane and to + + align:start position:0% +diffuse to the plasma membrane and to + + + align:start position:0% +diffuse to the plasma membrane and to +release neurotransmitter okay so the + + align:start position:0% +release neurotransmitter okay so the + + + align:start position:0% +release neurotransmitter okay so the +arrival of the action potential right so + + align:start position:0% +arrival of the action potential right so + + + align:start position:0% +arrival of the action potential right so +remember so in this case serotonin is + + align:start position:0% +remember so in this case serotonin is + + + align:start position:0% +remember so in this case serotonin is +going to be in blue right if serotonin + + align:start position:0% +going to be in blue right if serotonin + + + align:start position:0% +going to be in blue right if serotonin +is inside my vesicle here is going to + + align:start position:0% +is inside my vesicle here is going to + + + align:start position:0% +is inside my vesicle here is going to +need to exocytosis and now the serotonin + + align:start position:0% +need to exocytosis and now the serotonin + + + align:start position:0% +need to exocytosis and now the serotonin +is going to be outside the cell ready to + + align:start position:0% +is going to be outside the cell ready to + + + align:start position:0% +is going to be outside the cell ready to +bind to the receptor okay all right so + + align:start position:0% +bind to the receptor okay all right so + + + align:start position:0% +bind to the receptor okay all right so +as Miles pointed out you have an action + + align:start position:0% +as Miles pointed out you have an action + + + align:start position:0% +as Miles pointed out you have an action +potential the fusion should be triggered + + align:start position:0% +potential the fusion should be triggered + + + align:start position:0% +potential the fusion should be triggered +by the action potential in order to fuse + + align:start position:0% +by the action potential in order to fuse + + + align:start position:0% +by the action potential in order to fuse +there needs to be some signal inside the + + align:start position:0% +there needs to be some signal inside the + + + align:start position:0% +there needs to be some signal inside the +cytoplasm to tell the vesicle to fuse + + align:start position:0% +cytoplasm to tell the vesicle to fuse + + + align:start position:0% +cytoplasm to tell the vesicle to fuse +that signal is increased calcium ion + + align:start position:0% +that signal is increased calcium ion + + + align:start position:0% +that signal is increased calcium ion +concentration and then when calcium + + align:start position:0% +concentration and then when calcium + + + align:start position:0% +concentration and then when calcium +concentration increases in the cytoplasm + + align:start position:0% +concentration increases in the cytoplasm + + + align:start position:0% +concentration increases in the cytoplasm +that triggers the fusion of these + + align:start position:0% +that triggers the fusion of these + + + align:start position:0% +that triggers the fusion of these +vesicles and when you get fusion there's + + align:start position:0% +vesicles and when you get fusion there's + + + align:start position:0% +vesicles and when you get fusion there's +that's exocytosis and the serotonin is + + align:start position:0% +that's exocytosis and the serotonin is + + + align:start position:0% +that's exocytosis and the serotonin is +now on the outside of the cell where it + + align:start position:0% +now on the outside of the cell where it + + + align:start position:0% +now on the outside of the cell where it +can travel across the synaptic + + align:start position:0% +can travel across the synaptic + + + align:start position:0% +can travel across the synaptic +and bind to a receptor on the + + align:start position:0% +and bind to a receptor on the + + + align:start position:0% +and bind to a receptor on the +postsynaptic neuron okay so this fusion + + align:start position:0% +postsynaptic neuron okay so this fusion + + + align:start position:0% +postsynaptic neuron okay so this fusion +is when neurotransmitter is released + + align:start position:0% + + + + align:start position:0% + +neurotransmitter is released here okay + + align:start position:0% +neurotransmitter is released here okay + + + align:start position:0% +neurotransmitter is released here okay +in the way that this increasing calcium + + align:start position:0% +in the way that this increasing calcium + + + align:start position:0% +in the way that this increasing calcium +has to happen when the action potential + + align:start position:0% +has to happen when the action potential + + + align:start position:0% +has to happen when the action potential +arrives at the axon terminus so when it + + align:start position:0% +arrives at the axon terminus so when it + + + align:start position:0% +arrives at the axon terminus so when it +arrives in the axon terminus there's + + align:start position:0% +arrives in the axon terminus there's + + + align:start position:0% +arrives in the axon terminus there's +depolarization of that part of the cell + + align:start position:0% +depolarization of that part of the cell + + + align:start position:0% +depolarization of that part of the cell +and so there's a special type of protein + + align:start position:0% +and so there's a special type of protein + + + align:start position:0% +and so there's a special type of protein +called a voltage-gated calcium channel + + align:start position:0% +called a voltage-gated calcium channel + + + align:start position:0% +called a voltage-gated calcium channel +right these all these channels are very + + align:start position:0% +right these all these channels are very + + + align:start position:0% +right these all these channels are very +selective for different ions so a + + align:start position:0% +selective for different ions so a + + + align:start position:0% +selective for different ions so a +voltage-gated sodium channel isn't + + align:start position:0% +voltage-gated sodium channel isn't + + + align:start position:0% +voltage-gated sodium channel isn't +letting in all the ions outside the cell + + align:start position:0% +letting in all the ions outside the cell + + + align:start position:0% +letting in all the ions outside the cell +it's selective to sodium and this case + + align:start position:0% +it's selective to sodium and this case + + + align:start position:0% +it's selective to sodium and this case +this voltage-gated calcium channel is + + align:start position:0% +this voltage-gated calcium channel is + + + align:start position:0% +this voltage-gated calcium channel is +just gonna let in calcium and then + + align:start position:0% +just gonna let in calcium and then + + + align:start position:0% +just gonna let in calcium and then +there's a mechanism that links calcium + + align:start position:0% +there's a mechanism that links calcium + + + align:start position:0% +there's a mechanism that links calcium +entry to vesicle fusion and that's going + + align:start position:0% +entry to vesicle fusion and that's going + + + align:start position:0% +entry to vesicle fusion and that's going +to be shown here what you see on this + + align:start position:0% +to be shown here what you see on this + + + align:start position:0% +to be shown here what you see on this +docked synaptic vesicle is this calcium + + align:start position:0% +docked synaptic vesicle is this calcium + + + align:start position:0% +docked synaptic vesicle is this calcium +binding protein called sanic + + align:start position:0% +binding protein called sanic + + + align:start position:0% +binding protein called sanic +synaptotagmin that's present on the + + align:start position:0% +synaptotagmin that's present on the + + + align:start position:0% +synaptotagmin that's present on the +vesicle and so when calcium goes into + + align:start position:0% +vesicle and so when calcium goes into + + + align:start position:0% +vesicle and so when calcium goes into +the cytoplasm that protein binds to + + align:start position:0% +the cytoplasm that protein binds to + + + align:start position:0% +the cytoplasm that protein binds to +calcium and it activates the fusion + + align:start position:0% +calcium and it activates the fusion + + + align:start position:0% +calcium and it activates the fusion +machinery such that the plasma membrane + + align:start position:0% +machinery such that the plasma membrane + + + align:start position:0% +machinery such that the plasma membrane +of the vesicle fuses or the membrane of + + align:start position:0% +of the vesicle fuses or the membrane of + + + align:start position:0% +of the vesicle fuses or the membrane of +the vesicle fuses with the plasma + + align:start position:0% +the vesicle fuses with the plasma + + + align:start position:0% +the vesicle fuses with the plasma +membrane of the cell thus releasing the + + align:start position:0% +membrane of the cell thus releasing the + + + align:start position:0% +membrane of the cell thus releasing the +neurotransmitter into the synaptic cleft + + align:start position:0% + + + + align:start position:0% + +okay so this is this is what starts the + + align:start position:0% +okay so this is this is what starts the + + + align:start position:0% +okay so this is this is what starts the +signal now you probably know that you're + + align:start position:0% +signal now you probably know that you're + + + align:start position:0% +signal now you probably know that you're +you're these neurons are not active or + + align:start position:0% +you're these neurons are not active or + + + align:start position:0% +you're these neurons are not active or +on all the time so something has to + + align:start position:0% +on all the time so something has to + + + align:start position:0% +on all the time so something has to +terminate the signal usually quite + + align:start position:0% +terminate the signal usually quite + + + align:start position:0% +terminate the signal usually quite +rapidly okay so now I want to talk about + + align:start position:0% +rapidly okay so now I want to talk about + + + align:start position:0% +rapidly okay so now I want to talk about +that + + align:start position:0% + + + + align:start position:0% + +so like all signaling pathways signaling + + align:start position:0% +so like all signaling pathways signaling + + + align:start position:0% +so like all signaling pathways signaling +is useless if you can just turn it on + + align:start position:0% +is useless if you can just turn it on + + + align:start position:0% +is useless if you can just turn it on +you have to be able to toggle it on and + + align:start position:0% +you have to be able to toggle it on and + + + align:start position:0% +you have to be able to toggle it on and +off in order for biological systems to + + align:start position:0% +off in order for biological systems to + + + align:start position:0% +off in order for biological systems to +function properly right and that's the + + align:start position:0% +function properly right and that's the + + + align:start position:0% +function properly right and that's the +case with neurons if you just turn on a + + align:start position:0% +case with neurons if you just turn on a + + + align:start position:0% +case with neurons if you just turn on a +neuron and you don't have a way to turn + + align:start position:0% +neuron and you don't have a way to turn + + + align:start position:0% +neuron and you don't have a way to turn +it back off again then that's pretty + + align:start position:0% +it back off again then that's pretty + + + align:start position:0% +it back off again then that's pretty +useless okay and so we have to have a + + align:start position:0% +useless okay and so we have to have a + + + align:start position:0% +useless okay and so we have to have a +way to turn off the signal and if we + + align:start position:0% +way to turn off the signal and if we + + + align:start position:0% +way to turn off the signal and if we +consider the synapse this is the + + align:start position:0% +consider the synapse this is the + + + align:start position:0% +consider the synapse this is the +presynaptic neuron here I'm going to + + align:start position:0% +presynaptic neuron here I'm going to + + + align:start position:0% +presynaptic neuron here I'm going to +draw a postsynaptic neuron here and + + align:start position:0% +draw a postsynaptic neuron here and + + + align:start position:0% +draw a postsynaptic neuron here and +neurotransmitter is released by the + + align:start position:0% +neurotransmitter is released by the + + + align:start position:0% +neurotransmitter is released by the +presynaptic neuron this is the + + align:start position:0% +presynaptic neuron this is the + + + align:start position:0% +presynaptic neuron this is the +postsynaptic neuron here + + align:start position:0% +postsynaptic neuron here + + + align:start position:0% +postsynaptic neuron here +neurotransmitter is released into the + + align:start position:0% +neurotransmitter is released into the + + + align:start position:0% +neurotransmitter is released into the +synaptic cleft okay so this the region + + align:start position:0% +synaptic cleft okay so this the region + + + align:start position:0% +synaptic cleft okay so this the region +the sort of extracellular region between + + align:start position:0% +the sort of extracellular region between + + + align:start position:0% +the sort of extracellular region between +these two neurons is called the synaptic + + align:start position:0% +these two neurons is called the synaptic + + + align:start position:0% +these two neurons is called the synaptic +cleft so now the cell just dumped a + + align:start position:0% +cleft so now the cell just dumped a + + + align:start position:0% +cleft so now the cell just dumped a +whole buttload of neurotransmitter into + + align:start position:0% +whole buttload of neurotransmitter into + + + align:start position:0% +whole buttload of neurotransmitter into +the synaptic cleft right how is it going + + align:start position:0% +the synaptic cleft right how is it going + + + align:start position:0% +the synaptic cleft right how is it going +to turn this off what does it have to do + + align:start position:0% + + + + align:start position:0% + +yeah Stephen + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +so Stevens exactly right what Steven + + align:start position:0% +so Stevens exactly right what Steven + + + align:start position:0% +so Stevens exactly right what Steven +suggested is is there a way for the + + align:start position:0% +suggested is is there a way for the + + + align:start position:0% +suggested is is there a way for the +presynaptic neuron to reabsorb this + + align:start position:0% +presynaptic neuron to reabsorb this + + + align:start position:0% +presynaptic neuron to reabsorb this +neurotransmitter and thus recycle it + + align:start position:0% +neurotransmitter and thus recycle it + + + align:start position:0% +neurotransmitter and thus recycle it +okay and so there's so I could either + + align:start position:0% +okay and so there's so I could either + + + align:start position:0% +okay and so there's so I could either +reabsorb it or degrade the + + align:start position:0% +reabsorb it or degrade the + + + align:start position:0% +reabsorb it or degrade the +neurotransmitter it's a different + + align:start position:0% +neurotransmitter it's a different + + + align:start position:0% +neurotransmitter it's a different +process for different neurotransmitters + + align:start position:0% +process for different neurotransmitters + + + align:start position:0% +process for different neurotransmitters +for serotonin there are channels that + + align:start position:0% +for serotonin there are channels that + + + align:start position:0% +for serotonin there are channels that +are present in the plasma membrane and + + align:start position:0% +are present in the plasma membrane and + + + align:start position:0% +are present in the plasma membrane and +these mediate reuptake of the serotonin + + align:start position:0% +these mediate reuptake of the serotonin + + + align:start position:0% +these mediate reuptake of the serotonin +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so you have channels that are basically + + align:start position:0% +so you have channels that are basically + + + align:start position:0% +so you have channels that are basically +after the neurotransmitter is released + + align:start position:0% +after the neurotransmitter is released + + + align:start position:0% +after the neurotransmitter is released +it sucks the neurotransmitter back into + + align:start position:0% +it sucks the neurotransmitter back into + + + align:start position:0% +it sucks the neurotransmitter back into +the presynaptic cell such that it can + + align:start position:0% +the presynaptic cell such that it can + + + align:start position:0% +the presynaptic cell such that it can +then sort of reuse the neurotransmitter + + align:start position:0% +then sort of reuse the neurotransmitter + + + align:start position:0% +then sort of reuse the neurotransmitter +later on okay and so this process of + + align:start position:0% +later on okay and so this process of + + + align:start position:0% +later on okay and so this process of +reuptake highlights a very important or + + align:start position:0% +reuptake highlights a very important or + + + align:start position:0% +reuptake highlights a very important or +an important process that's been + + align:start position:0% +an important process that's been + + + align:start position:0% +an important process that's been +utilized by drug companies to create + + align:start position:0% +utilized by drug companies to create + + + align:start position:0% +utilized by drug companies to create +antidepressants so antidepressants like + + align:start position:0% +antidepressants so antidepressants like + + + align:start position:0% +antidepressants so antidepressants like +prozac and zoloft effect this reuptake + + align:start position:0% +prozac and zoloft effect this reuptake + + + align:start position:0% +prozac and zoloft effect this reuptake +process and what that does is it keeps + + align:start position:0% +process and what that does is it keeps + + + align:start position:0% +process and what that does is it keeps +the neurotransmitter in the synaptic + + align:start position:0% +the neurotransmitter in the synaptic + + + align:start position:0% +the neurotransmitter in the synaptic +cleft for longer such as it enhances the + + align:start position:0% +cleft for longer such as it enhances the + + + align:start position:0% +cleft for longer such as it enhances the +signaling and so the idea behind these + + align:start position:0% +signaling and so the idea behind these + + + align:start position:0% +signaling and so the idea behind these +drugs is that if you are suffering + + align:start position:0% +drugs is that if you are suffering + + + align:start position:0% +drugs is that if you are suffering +depression from a lack of serotonin then + + align:start position:0% +depression from a lack of serotonin then + + + align:start position:0% +depression from a lack of serotonin then +you can rescue that by preventing the + + align:start position:0% +you can rescue that by preventing the + + + align:start position:0% +you can rescue that by preventing the +rapid real take of the neurotransmitter + + align:start position:0% +rapid real take of the neurotransmitter + + + align:start position:0% +rapid real take of the neurotransmitter +into the cell after the synapse is + + align:start position:0% +into the cell after the synapse is + + + align:start position:0% +into the cell after the synapse is +stimulated and the neurotransmitter is + + align:start position:0% +stimulated and the neurotransmitter is + + + align:start position:0% +stimulated and the neurotransmitter is +released okay and so prozac Zoloft these + + align:start position:0% +released okay and so prozac Zoloft these + + + align:start position:0% +released okay and so prozac Zoloft these +are a class of drugs that are known as + + align:start position:0% +are a class of drugs that are known as + + + align:start position:0% +are a class of drugs that are known as +selective serotonin reuptake inhibitors + + align:start position:0% +selective serotonin reuptake inhibitors + + + align:start position:0% +selective serotonin reuptake inhibitors +serotonin reuptake + + align:start position:0% + + + + align:start position:0% + +inhibitors it's kind of a mouthful + + align:start position:0% +inhibitors it's kind of a mouthful + + + align:start position:0% +inhibitors it's kind of a mouthful +this is abbreviated SSRIs okay but the + + align:start position:0% +this is abbreviated SSRIs okay but the + + + align:start position:0% +this is abbreviated SSRIs okay but the +way they function is to leave the + + align:start position:0% +way they function is to leave the + + + align:start position:0% +way they function is to leave the +neurotransmitter in the synaptic cleft + + align:start position:0% +neurotransmitter in the synaptic cleft + + + align:start position:0% +neurotransmitter in the synaptic cleft +for longer so that you enhance signaling + + align:start position:0% +for longer so that you enhance signaling + + + align:start position:0% +for longer so that you enhance signaling +even if you have low levels of the + + align:start position:0% +even if you have low levels of the + + + align:start position:0% +even if you have low levels of the +neurotransmitter to begin with I also + + align:start position:0% +neurotransmitter to begin with I also + + + align:start position:0% +neurotransmitter to begin with I also +want to point out that if we look at + + align:start position:0% +want to point out that if we look at + + + align:start position:0% +want to point out that if we look at +this diagram here the synaptic vesicle + + align:start position:0% +this diagram here the synaptic vesicle + + + align:start position:0% +this diagram here the synaptic vesicle +fuses and then this releases the + + align:start position:0% +fuses and then this releases the + + + align:start position:0% +fuses and then this releases the +neurotransmitter but all the machinery + + align:start position:0% +neurotransmitter but all the machinery + + + align:start position:0% +neurotransmitter but all the machinery +on this vesicle is recycled by + + align:start position:0% +on this vesicle is recycled by + + + align:start position:0% +on this vesicle is recycled by +endocytosis such that it can be reused + + align:start position:0% +endocytosis such that it can be reused + + + align:start position:0% +endocytosis such that it can be reused +again okay + + align:start position:0% +again okay + + + align:start position:0% +again okay +so cells are really good at recycling + + align:start position:0% +so cells are really good at recycling + + + align:start position:0% +so cells are really good at recycling +stuff right if this is sort of the + + align:start position:0% +stuff right if this is sort of the + + + align:start position:0% +stuff right if this is sort of the +membrane to you endocytosis and then you + + align:start position:0% +membrane to you endocytosis and then you + + + align:start position:0% +membrane to you endocytosis and then you +can use it again later on okay and so + + align:start position:0% +can use it again later on okay and so + + + align:start position:0% +can use it again later on okay and so +there's recycling not only of the + + align:start position:0% +there's recycling not only of the + + + align:start position:0% +there's recycling not only of the +neurotransmitter but also all of the + + align:start position:0% +neurotransmitter but also all of the + + + align:start position:0% +neurotransmitter but also all of the +machinery on these synaptic vesicles + + align:start position:0% +machinery on these synaptic vesicles + + + align:start position:0% +machinery on these synaptic vesicles +that are responsible for the fusion + + align:start position:0% +that are responsible for the fusion + + + align:start position:0% +that are responsible for the fusion +event all right now I want to end by + + align:start position:0% +event all right now I want to end by + + + align:start position:0% +event all right now I want to end by +just telling you how this experiment + + align:start position:0% +just telling you how this experiment + + + align:start position:0% +just telling you how this experiment +works where we're able to activate + + align:start position:0% +works where we're able to activate + + + align:start position:0% +works where we're able to activate +specific neurons in a brain and that + + align:start position:0% +specific neurons in a brain and that + + + align:start position:0% +specific neurons in a brain and that +leads to the animal sort of waking up + + align:start position:0% +leads to the animal sort of waking up + + + align:start position:0% +leads to the animal sort of waking up +okay so in a normal neuron so this is + + align:start position:0% +okay so in a normal neuron so this is + + + align:start position:0% +okay so in a normal neuron so this is +the last part optogenetics and I'm gonna + + align:start position:0% +the last part optogenetics and I'm gonna + + + align:start position:0% +the last part optogenetics and I'm gonna +go through this very fast but normally + + align:start position:0% +go through this very fast but normally + + + align:start position:0% +go through this very fast but normally +you need a neurotransmitter to induce + + align:start position:0% +you need a neurotransmitter to induce + + + align:start position:0% +you need a neurotransmitter to induce +depolarization but what optogenetics is + + align:start position:0% +depolarization but what optogenetics is + + + align:start position:0% +depolarization but what optogenetics is +is an approach to control the activity + + align:start position:0% +is an approach to control the activity + + + align:start position:0% +is an approach to control the activity +of a cell with light okay so in this + + align:start position:0% +of a cell with light okay so in this + + + align:start position:0% +of a cell with light okay so in this +case we're gonna have light inducing + + align:start position:0% +case we're gonna have light inducing + + + align:start position:0% +case we're gonna have light inducing +depolarization and the way this is done + + align:start position:0% +depolarization and the way this is done + + + align:start position:0% +depolarization and the way this is done +is there's a protein discovered from + + align:start position:0% +is there's a protein discovered from + + + align:start position:0% +is there's a protein discovered from +from photosynthetic algae that's + + align:start position:0% +from photosynthetic algae that's + + + align:start position:0% +from photosynthetic algae that's +responsive to light and it is a sodium + + align:start position:0% +responsive to light and it is a sodium + + + align:start position:0% +responsive to light and it is a sodium +channel and this protein is called + + align:start position:0% +channel and this protein is called + + + align:start position:0% +channel and this protein is called +channelrhodopsin + + align:start position:0% + + + + align:start position:0% + +specifically CHR - and this is a + + align:start position:0% +specifically CHR - and this is a + + + align:start position:0% +specifically CHR - and this is a +light-sensitive protein where light + + align:start position:0% +light-sensitive protein where light + + + align:start position:0% +light-sensitive protein where light +induces sodium channel opening okay so + + align:start position:0% +induces sodium channel opening okay so + + + align:start position:0% +induces sodium channel opening okay so +that's gonna depolarize the cell and + + align:start position:0% +that's gonna depolarize the cell and + + + align:start position:0% +that's gonna depolarize the cell and +what you can do is if you have a gene + + align:start position:0% +what you can do is if you have a gene + + + align:start position:0% +what you can do is if you have a gene +that you know is specifically expressed + + align:start position:0% +that you know is specifically expressed + + + align:start position:0% +that you know is specifically expressed +in a certain type of neuron you can take + + align:start position:0% +in a certain type of neuron you can take + + + align:start position:0% +in a certain type of neuron you can take +the promoter and enhancer region of that + + align:start position:0% +the promoter and enhancer region of that + + + align:start position:0% +the promoter and enhancer region of that +gene and hook it up to this single + + align:start position:0% +gene and hook it up to this single + + + align:start position:0% +gene and hook it up to this single +component channelrhodopsin that open + + align:start position:0% +component channelrhodopsin that open + + + align:start position:0% +component channelrhodopsin that open +reading frame using recombinant DNA + + align:start position:0% +reading frame using recombinant DNA + + + align:start position:0% +reading frame using recombinant DNA +technology and if that's expressed + + align:start position:0% +technology and if that's expressed + + + align:start position:0% +technology and if that's expressed +specifically in the neurons that you're + + align:start position:0% +specifically in the neurons that you're + + + align:start position:0% +specifically in the neurons that you're +trying to test you can then shine a + + align:start position:0% +trying to test you can then shine a + + + align:start position:0% +trying to test you can then shine a +light into the brain of the organism and + + align:start position:0% +light into the brain of the organism and + + + align:start position:0% +light into the brain of the organism and +activate specifically this type of + + align:start position:0% +activate specifically this type of + + + align:start position:0% +activate specifically this type of +neuron and that allows you to test the + + align:start position:0% +neuron and that allows you to test the + + + align:start position:0% +neuron and that allows you to test the +function of the neuron in the behavior + + align:start position:0% +function of the neuron in the behavior + + + align:start position:0% +function of the neuron in the behavior +of an organism so in this case this + + align:start position:0% +of an organism so in this case this + + + align:start position:0% +of an organism so in this case this +mouse the light is shined into its brain + + align:start position:0% +mouse the light is shined into its brain + + + align:start position:0% +mouse the light is shined into its brain +and they're testing a specific type of + + align:start position:0% +and they're testing a specific type of + + + align:start position:0% +and they're testing a specific type of +neuron that is involved in arousal of + + align:start position:0% +neuron that is involved in arousal of + + + align:start position:0% +neuron that is involved in arousal of +the mouse and it wakes up oh it's not + + align:start position:0% +the mouse and it wakes up oh it's not + + + align:start position:0% +the mouse and it wakes up oh it's not +playing so here this is the this is a no + + align:start position:0% +playing so here this is the this is a no + + + align:start position:0% +playing so here this is the this is a no +this is the brain activity on the top + + align:start position:0% +this is the brain activity on the top + + + align:start position:0% +this is the brain activity on the top +and the muscle activity on the bottom so + + align:start position:0% +and the muscle activity on the bottom so + + + align:start position:0% +and the muscle activity on the bottom so +you're gonna see light there's the light + + align:start position:0% +you're gonna see light there's the light + + + align:start position:0% +you're gonna see light there's the light +you see it light going into the brain + + align:start position:0% +you see it light going into the brain + + + align:start position:0% +you see it light going into the brain +there they induce light at that + + align:start position:0% +there they induce light at that + + + align:start position:0% +there they induce light at that +frequency for a while and then they're + + align:start position:0% +frequency for a while and then they're + + + align:start position:0% +frequency for a while and then they're +gonna wait and see the mouse see if when + + align:start position:0% +gonna wait and see the mouse see if when + + + align:start position:0% +gonna wait and see the mouse see if when +the mouse wakes up and it's gonna wake + + align:start position:0% +the mouse wakes up and it's gonna wake + + + align:start position:0% +the mouse wakes up and it's gonna wake +up right now there it goes + + align:start position:0% +up right now there it goes + + + align:start position:0% +up right now there it goes +woke up you see now it's muscle activity + + align:start position:0% +woke up you see now it's muscle activity + + + align:start position:0% +woke up you see now it's muscle activity +is going okay so you can test the + + align:start position:0% +is going okay so you can test the + + + align:start position:0% +is going okay so you can test the +function of specific nerve cells using + + align:start position:0% +function of specific nerve cells using + + + align:start position:0% +function of specific nerve cells using +this approach and it's because you have + + align:start position:0% +this approach and it's because you have + + + align:start position:0% +this approach and it's because you have +a light-sensitive sodium channel so I'm + + align:start position:0% +a light-sensitive sodium channel so I'm + + + align:start position:0% +a light-sensitive sodium channel so I'm +done for today have a great weekend I + + align:start position:0% +done for today have a great weekend I + + + align:start position:0% +done for today have a great weekend I +will see you on Monday + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/9mYYNtaZJp8.txt b/9mYYNtaZJp8.txt new file mode 100644 index 0000000000000000000000000000000000000000..aeebbaf88db29faf1d8d02557af52d1902d61687 --- /dev/null +++ b/9mYYNtaZJp8.txt @@ -0,0 +1,8338 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit mitop courseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu okay uh we we want to I want + + align:start position:0% +ocw.mit.edu okay uh we we want to I want + + + align:start position:0% +ocw.mit.edu okay uh we we want to I want +to talk about the last Topic in the + + align:start position:0% +to talk about the last Topic in the + + + align:start position:0% +to talk about the last Topic in the +Scott book and then on Friday we'll + + align:start position:0% +Scott book and then on Friday we'll + + + align:start position:0% +Scott book and then on Friday we'll +start talking about + + align:start position:0% +start talking about + + + align:start position:0% +start talking about +sociobiology uh so you'll need to be + + align:start position:0% +sociobiology uh so you'll need to be + + + align:start position:0% +sociobiology uh so you'll need to be +reading the + + align:start position:0% +reading the + + + align:start position:0% +reading the +uh the book by + + align:start position:0% + + + + align:start position:0% + +elcock the mating and reproduction is + + align:start position:0% +elcock the mating and reproduction is + + + align:start position:0% +elcock the mating and reproduction is +very important for sociobiology + + align:start position:0% +very important for sociobiology + + + align:start position:0% +very important for sociobiology +so this + + align:start position:0% +so this + + + align:start position:0% +so this +is and of course it's inter it's + + align:start position:0% +is and of course it's inter it's + + + align:start position:0% +is and of course it's inter it's +important in ethology and other + + align:start position:0% +important in ethology and other + + + align:start position:0% +important in ethology and other +approaches to study of animal behavior + + align:start position:0% +approaches to study of animal behavior + + + align:start position:0% +approaches to study of animal behavior +and and + + align:start position:0% +and and + + + align:start position:0% +and and +uh so Scott is using mainly data of + + align:start position:0% +uh so Scott is using mainly data of + + + align:start position:0% +uh so Scott is using mainly data of +experimental ethology and as well as + + align:start position:0% +experimental ethology and as well as + + + align:start position:0% +experimental ethology and as well as +various observations by ethologists but + + align:start position:0% +various observations by ethologists but + + + align:start position:0% +various observations by ethologists but +then you'll see it's closely related to + + align:start position:0% +then you'll see it's closely related to + + + align:start position:0% +then you'll see it's closely related to +some of the studies of socio biology + + align:start position:0% +some of the studies of socio biology + + + align:start position:0% +some of the studies of socio biology +that we'll be talking + + align:start position:0% + + + + align:start position:0% + +about so when we talk about Evolution we + + align:start position:0% +about so when we talk about Evolution we + + + align:start position:0% +about so when we talk about Evolution we +we talk about both natural selection and + + align:start position:0% +we talk about both natural selection and + + + align:start position:0% +we talk about both natural selection and +sex sexual selection that were both + + align:start position:0% +sex sexual selection that were both + + + align:start position:0% +sex sexual selection that were both +discussing by Charles + + align:start position:0% +discussing by Charles + + + align:start position:0% +discussing by Charles +Darwin and you should have a clear + + align:start position:0% +Darwin and you should have a clear + + + align:start position:0% +Darwin and you should have a clear +understanding of the difference in the + + align:start position:0% +understanding of the difference in the + + + align:start position:0% +understanding of the difference in the +meaning uh we've talked about both of + + align:start position:0% +meaning uh we've talked about both of + + + align:start position:0% +meaning uh we've talked about both of +them in the + + align:start position:0% +them in the + + + align:start position:0% +them in the +class you should be able to give ad uh + + align:start position:0% +class you should be able to give ad uh + + + align:start position:0% +class you should be able to give ad uh +examples of each of them and for every + + align:start position:0% +examples of each of them and for every + + + align:start position:0% +examples of each of them and for every +time you discuss a + + align:start position:0% +time you discuss a + + + align:start position:0% +time you discuss a +trait + + align:start position:0% +trait + + + align:start position:0% +trait +uh besides understanding whether it + + align:start position:0% +uh besides understanding whether it + + + align:start position:0% +uh besides understanding whether it +arose from natural selection or sex + + align:start position:0% +arose from natural selection or sex + + + align:start position:0% +arose from natural selection or sex +sexual selection or some combination you + + align:start position:0% +sexual selection or some combination you + + + align:start position:0% +sexual selection or some combination you +have to consider the likely costs and + + align:start position:0% +have to consider the likely costs and + + + align:start position:0% +have to consider the likely costs and +benefits uh + + align:start position:0% +benefits uh + + + align:start position:0% +benefits uh +and what do we mean by costs and + + align:start position:0% +and what do we mean by costs and + + + align:start position:0% +and what do we mean by costs and +benefits we always will take the + + align:start position:0% +benefits we always will take the + + + align:start position:0% +benefits we always will take the +sociobiological view that we're talking + + align:start position:0% +sociobiological view that we're talking + + + align:start position:0% +sociobiological view that we're talking +about not benefits for individual + + align:start position:0% +about not benefits for individual + + + align:start position:0% +about not benefits for individual +survival + + align:start position:0% +survival + + + align:start position:0% +survival +necessarily but for increasing the + + align:start position:0% +necessarily but for increasing the + + + align:start position:0% +necessarily but for increasing the +likelihood of passing on the genes + + align:start position:0% +likelihood of passing on the genes + + + align:start position:0% +likelihood of passing on the genes +this is the way it's used in + + align:start position:0% +this is the way it's used in + + + align:start position:0% +this is the way it's used in +sociobiology + + align:start position:0% +sociobiology + + + align:start position:0% +sociobiology +uh and obviously traits in order to + + align:start position:0% +uh and obviously traits in order to + + + align:start position:0% +uh and obviously traits in order to +evolve uh the benefits have to exceed + + align:start position:0% +evolve uh the benefits have to exceed + + + align:start position:0% +evolve uh the benefits have to exceed +the cost it doesn't mean there aren't + + align:start position:0% +the cost it doesn't mean there aren't + + + align:start position:0% +the cost it doesn't mean there aren't +costs and sometimes it's a puzzle + + align:start position:0% +costs and sometimes it's a puzzle + + + align:start position:0% +costs and sometimes it's a puzzle +just they see because it seems the cost + + align:start position:0% +just they see because it seems the cost + + + align:start position:0% +just they see because it seems the cost +is so drastic like if the female eats + + align:start position:0% +is so drastic like if the female eats + + + align:start position:0% +is so drastic like if the female eats +the male after mating that do seems to + + align:start position:0% +the male after mating that do seems to + + + align:start position:0% +the male after mating that do seems to +be a rather high cost to the mail so + + align:start position:0% +be a rather high cost to the mail so + + + align:start position:0% +be a rather high cost to the mail so +we'll bring that up uh later in the + + align:start position:0% +we'll bring that up uh later in the + + + align:start position:0% +we'll bring that up uh later in the +class + + align:start position:0% +class + + + align:start position:0% +class +because that's a typical darwinian + + align:start position:0% +because that's a typical darwinian + + + align:start position:0% +because that's a typical darwinian +puzzle when first when you first look at + + align:start position:0% +puzzle when first when you first look at + + + align:start position:0% +puzzle when first when you first look at +the the + + align:start position:0% +the the + + + align:start position:0% +the the +data so when we're talking it's easiest + + align:start position:0% +data so when we're talking it's easiest + + + align:start position:0% +data so when we're talking it's easiest +when just trying to contrast natural and + + align:start position:0% +when just trying to contrast natural and + + + align:start position:0% +when just trying to contrast natural and +sexual sexual selection to First + + align:start position:0% +sexual sexual selection to First + + + align:start position:0% +sexual sexual selection to First +consider is it sexual + + align:start position:0% +consider is it sexual + + + align:start position:0% +consider is it sexual +selection and we we've given examples of + + align:start position:0% +selection and we we've given examples of + + + align:start position:0% +selection and we we've given examples of +that already like your tail feathers of + + align:start position:0% +that already like your tail feathers of + + + align:start position:0% +that already like your tail feathers of +the female + + align:start position:0% +the female + + + align:start position:0% +the female +peacocks or or a + + align:start position:0% +peacocks or or a + + + align:start position:0% +peacocks or or a +peasant the red color the bright red + + align:start position:0% +peasant the red color the bright red + + + align:start position:0% +peasant the red color the bright red +color of the male cardinal it makes him + + align:start position:0% +color of the male cardinal it makes him + + + align:start position:0% +color of the male cardinal it makes him +stand out particularly in against the + + align:start position:0% +stand out particularly in against the + + + align:start position:0% +stand out particularly in against the +snow and winter it makes him very + + align:start position:0% +snow and winter it makes him very + + + align:start position:0% +snow and winter it makes him very +conspicuous to + + align:start position:0% +conspicuous to + + + align:start position:0% +conspicuous to +Predators as well as to the female we + + align:start position:0% +Predators as well as to the female we + + + align:start position:0% +Predators as well as to the female we +talked about the long tail the sword + + align:start position:0% +talked about the long tail the sword + + + align:start position:0% +talked about the long tail the sword +tail fish the Lion's man of course is a + + align:start position:0% +tail fish the Lion's man of course is a + + + align:start position:0% +tail fish the Lion's man of course is a +common one a Stags + + align:start position:0% +common one a Stags + + + align:start position:0% +common one a Stags +antlers why do we say they evolve by + + align:start position:0% +antlers why do we say they evolve by + + + align:start position:0% +antlers why do we say they evolve by +sexual selection because they evolve + + align:start position:0% +sexual selection because they evolve + + + align:start position:0% +sexual selection because they evolve +because the female pre ERS males with + + align:start position:0% +because the female pre ERS males with + + + align:start position:0% +because the female pre ERS males with +those + + align:start position:0% + + + + align:start position:0% + +traits so they benefit + + align:start position:0% +traits so they benefit + + + align:start position:0% +traits so they benefit +reproduction for the male because it + + align:start position:0% +reproduction for the male because it + + + align:start position:0% +reproduction for the male because it +makes him more attractive if you can't + + align:start position:0% +makes him more attractive if you can't + + + align:start position:0% +makes him more attractive if you can't +attract females to mate with and he + + align:start position:0% +attract females to mate with and he + + + align:start position:0% +attract females to mate with and he +won't pass on so many genes if + + align:start position:0% +won't pass on so many genes if + + + align:start position:0% +won't pass on so many genes if +any + + align:start position:0% +any + + + align:start position:0% +any +now usually you're talking about the + + align:start position:0% +now usually you're talking about the + + + align:start position:0% +now usually you're talking about the +appearance of the male when you're + + align:start position:0% +appearance of the male when you're + + + align:start position:0% +appearance of the male when you're +talking about sexual selection but it + + align:start position:0% +talking about sexual selection but it + + + align:start position:0% +talking about sexual selection but it +does happen it affects the + + align:start position:0% +does happen it affects the + + + align:start position:0% +does happen it affects the +characteristics of female too especially + + align:start position:0% +characteristics of female too especially + + + align:start position:0% +characteristics of female too especially +if males exercise + + align:start position:0% +if males exercise + + + align:start position:0% +if males exercise +Choice okay and so we'll talk about that + + align:start position:0% +Choice okay and so we'll talk about that + + + align:start position:0% +Choice okay and so we'll talk about that +too well if it didn't evolve by sexual + + align:start position:0% +too well if it didn't evolve by sexual + + + align:start position:0% +too well if it didn't evolve by sexual +selection + + align:start position:0% +selection + + + align:start position:0% +selection +then the traits evolv still by natural + + align:start position:0% +then the traits evolv still by natural + + + align:start position:0% +then the traits evolv still by natural +selection the factors that enable + + align:start position:0% +selection the factors that enable + + + align:start position:0% +selection the factors that enable +survival at least through the age of + + align:start position:0% +survival at least through the age of + + + align:start position:0% +survival at least through the age of +reproduction and in many cases the age + + align:start position:0% +reproduction and in many cases the age + + + align:start position:0% +reproduction and in many cases the age +of reproduction includes + + align:start position:0% +of reproduction includes + + + align:start position:0% +of reproduction includes +rude tending care of + + align:start position:0% +rude tending care of + + + align:start position:0% +rude tending care of +young and maybe in our species uh care + + align:start position:0% +young and maybe in our species uh care + + + align:start position:0% +young and maybe in our species uh care +of the young of our + + align:start position:0% +of the young of our + + + align:start position:0% +of the young of our +young okay + + align:start position:0% +young okay + + + align:start position:0% +young okay +so we talked remember about the birds of + + align:start position:0% +so we talked remember about the birds of + + + align:start position:0% +so we talked remember about the birds of +paradise we saw the example of + + align:start position:0% +paradise we saw the example of + + + align:start position:0% +paradise we saw the example of +the uh this is + + align:start position:0% +the uh this is + + + align:start position:0% +the uh this is +the a bird of one of the birds of + + align:start position:0% +the a bird of one of the birds of + + + align:start position:0% +the a bird of one of the birds of +paradise Goldie bird of + + align:start position:0% +paradise Goldie bird of + + + align:start position:0% +paradise Goldie bird of +paradise uh in the video that we saw + + align:start position:0% +paradise uh in the video that we saw + + + align:start position:0% +paradise uh in the video that we saw +with the the dancing bird of paradise it + + align:start position:0% +with the the dancing bird of paradise it + + + align:start position:0% +with the the dancing bird of paradise it +was a paradise rifle bird from + + align:start position:0% +was a paradise rifle bird from + + + align:start position:0% +was a paradise rifle bird from +Australia these animal these birds occur + + align:start position:0% +Australia these animal these birds occur + + + align:start position:0% +Australia these animal these birds occur +in the within Indonesia and also in + + align:start position:0% +in the within Indonesia and also in + + + align:start position:0% +in the within Indonesia and also in +eastern Australia we were the I believe + + align:start position:0% +eastern Australia we were the I believe + + + align:start position:0% +eastern Australia we were the I believe +the video we saw was all of + + align:start position:0% +the video we saw was all of + + + align:start position:0% +the video we saw was all of +the Australian + + align:start position:0% + + + + align:start position:0% + +birds why do you think the elaboration + + align:start position:0% +birds why do you think the elaboration + + + align:start position:0% +birds why do you think the elaboration +of these feathers has gone to such + + align:start position:0% +of these feathers has gone to such + + + align:start position:0% +of these feathers has gone to such +extremes + + align:start position:0% +extremes + + + align:start position:0% +extremes +doesn't it have + + align:start position:0% + + + + align:start position:0% + +costs I mean a male that's having to + + align:start position:0% +costs I mean a male that's having to + + + align:start position:0% +costs I mean a male that's having to +care around carry around these feathers + + align:start position:0% +care around carry around these feathers + + + align:start position:0% +care around carry around these feathers +or look at + + align:start position:0% +or look at + + + align:start position:0% +or look at +this the peacock + + align:start position:0% + + + + align:start position:0% + +here it seems to be somewhat of a burden + + align:start position:0% +here it seems to be somewhat of a burden + + + align:start position:0% +here it seems to be somewhat of a burden +to have feathers that long and yet the + + align:start position:0% +to have feathers that long and yet the + + + align:start position:0% +to have feathers that long and yet the +females prefer + + align:start position:0% +females prefer + + + align:start position:0% +females prefer +it you know if you give a + + align:start position:0% +it you know if you give a + + + align:start position:0% +it you know if you give a +female uh peacock a choice between males + + align:start position:0% +female uh peacock a choice between males + + + align:start position:0% +female uh peacock a choice between males +with areas here's a I took this picture + + align:start position:0% +with areas here's a I took this picture + + + align:start position:0% +with areas here's a I took this picture +myself at the Boston Zoological Society + + align:start position:0% +myself at the Boston Zoological Society + + + align:start position:0% +myself at the Boston Zoological Society +Park and uh it shows the string male + + align:start position:0% +Park and uh it shows the string male + + + align:start position:0% +Park and uh it shows the string male +he's displaying his tail feathers + + align:start position:0% +he's displaying his tail feathers + + + align:start position:0% +he's displaying his tail feathers +there's the pan in + + align:start position:0% +there's the pan in + + + align:start position:0% +there's the pan in +front + + align:start position:0% +front + + + align:start position:0% +front +uh with feathers like that I mean how + + align:start position:0% +uh with feathers like that I mean how + + + align:start position:0% +uh with feathers like that I mean how +does he get away from predators you see + + align:start position:0% +does he get away from predators you see + + + align:start position:0% +does he get away from predators you see +now in the case of these birds it's it's + + align:start position:0% +now in the case of these birds it's it's + + + align:start position:0% +now in the case of these birds it's it's +fairly easy to understand because they + + align:start position:0% +fairly easy to understand because they + + + align:start position:0% +fairly easy to understand because they +don't have many in the environments + + align:start position:0% +don't have many in the environments + + + align:start position:0% +don't have many in the environments +where these birds are found they don't + + align:start position:0% +where these birds are found they don't + + + align:start position:0% +where these birds are found they don't +have many + + align:start position:0% +have many + + + align:start position:0% +have many +predators okay + + align:start position:0% +predators okay + + + align:start position:0% +predators okay +so are there still costs well if it went + + align:start position:0% +so are there still costs well if it went + + + align:start position:0% +so are there still costs well if it went +too far what would the cost be it would + + align:start position:0% +too far what would the cost be it would + + + align:start position:0% +too far what would the cost be it would +start interfering with its ability to + + align:start position:0% +start interfering with its ability to + + + align:start position:0% +start interfering with its ability to +forage just to locomote get + + align:start position:0% +forage just to locomote get + + + align:start position:0% +forage just to locomote get +around okay so these are there's + + align:start position:0% +around okay so these are there's + + + align:start position:0% +around okay so these are there's +certainly limits to how far sexual + + align:start position:0% +certainly limits to how far sexual + + + align:start position:0% +certainly limits to how far sexual +selection can + + align:start position:0% + + + + align:start position:0% + +go + + align:start position:0% +go + + + align:start position:0% +go +here's the MC Darwin was of course had + + align:start position:0% +here's the MC Darwin was of course had + + + align:start position:0% +here's the MC Darwin was of course had +introduced this idea of sexual + + align:start position:0% +introduced this idea of sexual + + + align:start position:0% +introduced this idea of sexual +selection and he was made fun of + + align:start position:0% + + + + align:start position:0% + +in among other ways by + + align:start position:0% +in among other ways by + + + align:start position:0% +in among other ways by +cartoonists and here it shows the + + align:start position:0% +cartoonists and here it shows the + + + align:start position:0% +cartoonists and here it shows the +Victorian cartoonists uh made fun of + + align:start position:0% +Victorian cartoonists uh made fun of + + + align:start position:0% +Victorian cartoonists uh made fun of +Darwin's ideas about sexual + + align:start position:0% +Darwin's ideas about sexual + + + align:start position:0% +Darwin's ideas about sexual +selection uh and the importance of + + align:start position:0% +selection uh and the importance of + + + align:start position:0% +selection uh and the importance of +visual displays is uh it shows him here + + align:start position:0% +visual displays is uh it shows him here + + + align:start position:0% +visual displays is uh it shows him here +in inspecting the mimicking of stop + + align:start position:0% +in inspecting the mimicking of stop + + + align:start position:0% +in inspecting the mimicking of stop +pisia what is + + align:start position:0% +pisia what is + + + align:start position:0% +pisia what is +that the very large buts in females of + + align:start position:0% +that the very large buts in females of + + + align:start position:0% +that the very large buts in females of +certain groups of + + align:start position:0% +certain groups of + + + align:start position:0% +certain groups of +humans and it + + align:start position:0% +humans and it + + + align:start position:0% +humans and it +became a Victorian style to wear + + align:start position:0% +became a Victorian style to wear + + + align:start position:0% +became a Victorian style to wear +Buffet so Darwin of course had a ready + + align:start position:0% +Buffet so Darwin of course had a ready + + + align:start position:0% +Buffet so Darwin of course had a ready +interpretation of that + + align:start position:0% +interpretation of that + + + align:start position:0% +interpretation of that +they wouldn't do it if males didn't like + + align:start position:0% + + + + align:start position:0% + +it if you want to know more about stopa + + align:start position:0% +it if you want to know more about stopa + + + align:start position:0% +it if you want to know more about stopa +just go to Google don't go to Google + + align:start position:0% +just go to Google don't go to Google + + + align:start position:0% +just go to Google don't go to Google +Scholar although you can go there too + + align:start position:0% +Scholar although you can go there too + + + align:start position:0% +Scholar although you can go there too +and you will find the scholarly papers + + align:start position:0% +and you will find the scholarly papers + + + align:start position:0% +and you will find the scholarly papers +but if you just go to the regular Google + + align:start position:0% +but if you just go to the regular Google + + + align:start position:0% +but if you just go to the regular Google +you'll find all kinds of information + + align:start position:0% +you'll find all kinds of information + + + align:start position:0% +you'll find all kinds of information +photographs comments some of them with + + align:start position:0% +photographs comments some of them with + + + align:start position:0% +photographs comments some of them with +tongue and cheek some of them claiming + + align:start position:0% +tongue and cheek some of them claiming + + + align:start position:0% +tongue and cheek some of them claiming +it's + + align:start position:0% +it's + + + align:start position:0% +it's +racism and and others really most of + + align:start position:0% +racism and and others really most of + + + align:start position:0% +racism and and others really most of +it's just very interesting and it + + align:start position:0% +it's just very interesting and it + + + align:start position:0% +it's just very interesting and it +illustrates Variety in human + + align:start position:0% +illustrates Variety in human + + + align:start position:0% +illustrates Variety in human +evolution I think when we talk about + + align:start position:0% +evolution I think when we talk about + + + align:start position:0% +evolution I think when we talk about +socio biology this will come up + + align:start position:0% +socio biology this will come up + + + align:start position:0% +socio biology this will come up +again this a particular + + align:start position:0% +again this a particular + + + align:start position:0% +again this a particular +illustration not in cartoons but in real + + align:start position:0% +illustration not in cartoons but in real + + + align:start position:0% +illustration not in cartoons but in real +people okay and now this is the next + + align:start position:0% +people okay and now this is the next + + + align:start position:0% +people okay and now this is the next +concept that Scott brings up the very + + align:start position:0% +concept that Scott brings up the very + + + align:start position:0% +concept that Scott brings up the very +ations and reproductive + + align:start position:0% +ations and reproductive + + + align:start position:0% +ations and reproductive +investment uh by the male and the female + + align:start position:0% +investment uh by the male and the female + + + align:start position:0% +investment uh by the male and the female +of a species because often they differ + + align:start position:0% +of a species because often they differ + + + align:start position:0% +of a species because often they differ +uh + + align:start position:0% +uh + + + align:start position:0% +uh +considerably we saw when we talked about + + align:start position:0% +considerably we saw when we talked about + + + align:start position:0% +considerably we saw when we talked about +sticklebacks early in the class that the + + align:start position:0% +sticklebacks early in the class that the + + + align:start position:0% +sticklebacks early in the class that the +male does all the nesting and care of + + align:start position:0% +male does all the nesting and care of + + + align:start position:0% +male does all the nesting and care of +the eggs so the male is making a big + + align:start position:0% +the eggs so the male is making a big + + + align:start position:0% +the eggs so the male is making a big +investment a reproductive investment the + + align:start position:0% +investment a reproductive investment the + + + align:start position:0% +investment a reproductive investment the +female doesn't make so many so much + + align:start position:0% +female doesn't make so many so much + + + align:start position:0% +female doesn't make so many so much +reproductive investment + + align:start position:0% +reproductive investment + + + align:start position:0% +reproductive investment +in other species of fish the male just + + align:start position:0% +in other species of fish the male just + + + align:start position:0% +in other species of fish the male just +leaves after fertilizing the eggs he + + align:start position:0% +leaves after fertilizing the eggs he + + + align:start position:0% +leaves after fertilizing the eggs he +seems to make heat in that those species + + align:start position:0% +seems to make heat in that those species + + + align:start position:0% +seems to make heat in that those species +it's the male it's not making any + + align:start position:0% +it's the male it's not making any + + + align:start position:0% +it's the male it's not making any +reproductive + + align:start position:0% +reproductive + + + align:start position:0% +reproductive +investment so of course then their + + align:start position:0% +investment so of course then their + + + align:start position:0% +investment so of course then their +strategies are going to + + align:start position:0% + + + + align:start position:0% + +differ and you'll can predict difference + + align:start position:0% +differ and you'll can predict difference + + + align:start position:0% +differ and you'll can predict difference +very great differences in behavior and + + align:start position:0% +very great differences in behavior and + + + align:start position:0% +very great differences in behavior and +choices of those the male and the + + align:start position:0% +choices of those the male and the + + + align:start position:0% +choices of those the male and the +female in Lions the female has to invest + + align:start position:0% +female in Lions the female has to invest + + + align:start position:0% +female in Lions the female has to invest +more in two years that includes + + align:start position:0% +more in two years that includes + + + align:start position:0% +more in two years that includes +gestation and nearly two years of care + + align:start position:0% +gestation and nearly two years of care + + + align:start position:0% +gestation and nearly two years of care +of the young the males do comparatively + + align:start position:0% +of the young the males do comparatively + + + align:start position:0% +of the young the males do comparatively +little because even when the female is + + align:start position:0% +little because even when the female is + + + align:start position:0% +little because even when the female is +Dre and young she often is still doing + + align:start position:0% +Dre and young she often is still doing + + + align:start position:0% +Dre and young she often is still doing +much of the hunting though the male will + + align:start position:0% +much of the hunting though the male will + + + align:start position:0% +much of the hunting though the male will +hunt as + + align:start position:0% + + + + align:start position:0% + +well the spotted sandpipers an example + + align:start position:0% +well the spotted sandpipers an example + + + align:start position:0% +well the spotted sandpipers an example +where the males do most of the brood + + align:start position:0% +where the males do most of the brood + + + align:start position:0% +where the males do most of the brood +tending and the female she will help + + align:start position:0% +tending and the female she will help + + + align:start position:0% +tending and the female she will help +sometimes for a while and then she just + + align:start position:0% +sometimes for a while and then she just + + + align:start position:0% +sometimes for a while and then she just +leaves she goes off and lays another + + align:start position:0% +leaves she goes off and lays another + + + align:start position:0% +leaves she goes off and lays another +clutch of eggs of four she L LS four + + align:start position:0% +clutch of eggs of four she L LS four + + + align:start position:0% +clutch of eggs of four she L LS four +eggs at a time in each Nest she goes off + + align:start position:0% +eggs at a time in each Nest she goes off + + + align:start position:0% +eggs at a time in each Nest she goes off +to lay another clutch of for eggs with a + + align:start position:0% +to lay another clutch of for eggs with a + + + align:start position:0% +to lay another clutch of for eggs with a +different + + align:start position:0% + + + + align:start position:0% + +nail so again it's the male making the + + align:start position:0% +nail so again it's the male making the + + + align:start position:0% +nail so again it's the male making the +reproductive investment and I mean what + + align:start position:0% +reproductive investment and I mean what + + + align:start position:0% +reproductive investment and I mean what +would happen so he leaves what about the + + align:start position:0% +would happen so he leaves what about the + + + align:start position:0% +would happen so he leaves what about the +male well if he leaves then his + + align:start position:0% +male well if he leaves then his + + + align:start position:0% +male well if he leaves then his +reproductive investment goes to zero for + + align:start position:0% +reproductive investment goes to zero for + + + align:start position:0% +reproductive investment goes to zero for +that span of time he's already put time + + align:start position:0% +that span of time he's already put time + + + align:start position:0% +that span of time he's already put time +into it if he + + align:start position:0% +into it if he + + + align:start position:0% +into it if he +wants his jeans to be passed on he's got + + align:start position:0% +wants his jeans to be passed on he's got + + + align:start position:0% +wants his jeans to be passed on he's got +to stay and take care of those + + align:start position:0% +to stay and take care of those + + + align:start position:0% +to stay and take care of those +chicks whereas the + + align:start position:0% +chicks whereas the + + + align:start position:0% +chicks whereas the +female she gets it for free or not for + + align:start position:0% +female she gets it for free or not for + + + align:start position:0% +female she gets it for free or not for +free she still had to lay the eggs and + + align:start position:0% +free she still had to lay the eggs and + + + align:start position:0% +free she still had to lay the eggs and +that takes a lot of energy and a lot of + + align:start position:0% +that takes a lot of energy and a lot of + + + align:start position:0% +that takes a lot of energy and a lot of +foraging but she can increase her + + align:start position:0% +foraging but she can increase her + + + align:start position:0% +foraging but she can increase her +reproductive uh output simply by laying + + align:start position:0% +reproductive uh output simply by laying + + + align:start position:0% +reproductive uh output simply by laying +more + + align:start position:0% +more + + + align:start position:0% +more +eggs getting another egg male to bring + + align:start position:0% +eggs getting another egg male to bring + + + align:start position:0% +eggs getting another egg male to bring +the food + + align:start position:0% +the food + + + align:start position:0% +the food +and help rear the + + align:start position:0% +and help rear the + + + align:start position:0% +and help rear the +eggs we'll come back to the + + align:start position:0% + + + + align:start position:0% + +sandpipers so let's talk a little more + + align:start position:0% +sandpipers so let's talk a little more + + + align:start position:0% +sandpipers so let's talk a little more +about how the male and female + + align:start position:0% +about how the male and female + + + align:start position:0% +about how the male and female +uh can use very different ways to + + align:start position:0% +uh can use very different ways to + + + align:start position:0% +uh can use very different ways to +maximize their reproductive output in + + align:start position:0% +maximize their reproductive output in + + + align:start position:0% +maximize their reproductive output in +most cases in many cases certainly we + + align:start position:0% +most cases in many cases certainly we + + + align:start position:0% +most cases in many cases certainly we +just saw examples where that's not true + + align:start position:0% +just saw examples where that's not true + + + align:start position:0% +just saw examples where that's not true +but the the male can increase his number + + align:start position:0% +but the the male can increase his number + + + align:start position:0% +but the the male can increase his number +of Offspring uh just by mating + + align:start position:0% +of Offspring uh just by mating + + + align:start position:0% +of Offspring uh just by mating +indiscriminately mate with as many + + align:start position:0% +indiscriminately mate with as many + + + align:start position:0% +indiscriminately mate with as many +females as + + align:start position:0% +females as + + + align:start position:0% +females as +possible if the female is doing the + + align:start position:0% +possible if the female is doing the + + + align:start position:0% +possible if the female is doing the +brute tending and he doesn't have to do + + align:start position:0% +brute tending and he doesn't have to do + + + align:start position:0% +brute tending and he doesn't have to do +it that would be his best best strategy + + align:start position:0% +it that would be his best best strategy + + + align:start position:0% +it that would be his best best strategy +if he wants to maximize reproductive + + align:start position:0% +if he wants to maximize reproductive + + + align:start position:0% +if he wants to maximize reproductive +output and you see that + + align:start position:0% +output and you see that + + + align:start position:0% +output and you see that +okay the female has limited egg + + align:start position:0% +okay the female has limited egg + + + align:start position:0% +okay the female has limited egg +production so she is more interested in + + align:start position:0% +production so she is more interested in + + + align:start position:0% +production so she is more interested in +the male that in just maximizing the + + align:start position:0% +the male that in just maximizing the + + + align:start position:0% +the male that in just maximizing the +quality of The Offspring that is given + + align:start position:0% +quality of The Offspring that is given + + + align:start position:0% +quality of The Offspring that is given +the best + + align:start position:0% +the best + + + align:start position:0% +the best +chance of of surviving and reproducing + + align:start position:0% +chance of of surviving and reproducing + + + align:start position:0% +chance of of surviving and reproducing +themselves so she's going to have a + + align:start position:0% +themselves so she's going to have a + + + align:start position:0% +themselves so she's going to have a +great interest in finding good + + align:start position:0% +great interest in finding good + + + align:start position:0% +great interest in finding good +genes and her + + align:start position:0% +genes and her + + + align:start position:0% +genes and her +mating or good + + align:start position:0% +mating or good + + + align:start position:0% +mating or good +resources from the + + align:start position:0% + + + + align:start position:0% + +male so because of these different + + align:start position:0% +male so because of these different + + + align:start position:0% +male so because of these different +interests of the male and female that + + align:start position:0% +interests of the male and female that + + + align:start position:0% +interests of the male and female that +that offer often are considerably + + align:start position:0% +that offer often are considerably + + + align:start position:0% +that offer often are considerably +different though it varies just how in + + align:start position:0% +different though it varies just how in + + + align:start position:0% +different though it varies just how in +different species but you always have + + align:start position:0% +different species but you always have + + + align:start position:0% +different species but you always have +this male female difference in in + + align:start position:0% +this male female difference in in + + + align:start position:0% +this male female difference in in +uh their production of the gamet so um + + align:start position:0% +uh their production of the gamet so um + + + align:start position:0% +uh their production of the gamet so um +the result is various you can call them + + align:start position:0% +the result is various you can call them + + + align:start position:0% +the result is various you can call them +compromises between the interests of the + + align:start position:0% +compromises between the interests of the + + + align:start position:0% +compromises between the interests of the +male and interests of the + + align:start position:0% +male and interests of the + + + align:start position:0% +male and interests of the +female and when we say this and talking + + align:start position:0% +female and when we say this and talking + + + align:start position:0% +female and when we say this and talking +about compromises I don't mean these + + align:start position:0% +about compromises I don't mean these + + + align:start position:0% +about compromises I don't mean these +animals are aware of it okay but looked + + align:start position:0% +animals are aware of it okay but looked + + + align:start position:0% +animals are aware of it okay but looked +at from as an evolutionary biologist or + + align:start position:0% +at from as an evolutionary biologist or + + + align:start position:0% +at from as an evolutionary biologist or +sociobiologist + + align:start position:0% +sociobiologist + + + align:start position:0% +sociobiologist +uh you interpret it in terms of + + align:start position:0% +uh you interpret it in terms of + + + align:start position:0% +uh you interpret it in terms of +evolution not in terms of what they're + + align:start position:0% +evolution not in terms of what they're + + + align:start position:0% +evolution not in terms of what they're +aware of + + align:start position:0% + + + + align:start position:0% + +okay and of course we know the + + align:start position:0% +okay and of course we know the + + + align:start position:0% +okay and of course we know the +reproductive investment varies we've + + align:start position:0% +reproductive investment varies we've + + + align:start position:0% +reproductive investment varies we've +already talked about that and so now we + + align:start position:0% +already talked about that and so now we + + + align:start position:0% +already talked about that and so now we +have to talk about mate Choice which + + align:start position:0% +have to talk about mate Choice which + + + align:start position:0% +have to talk about mate Choice which +varies a lot and there's a lot of + + align:start position:0% +varies a lot and there's a lot of + + + align:start position:0% +varies a lot and there's a lot of +studies of it and by sociobiologists and + + align:start position:0% + + + + align:start position:0% + +others made Choice by + + align:start position:0% +others made Choice by + + + align:start position:0% +others made Choice by +females appears + + align:start position:0% +females appears + + + align:start position:0% +females appears +in most cases in almost all cases to be + + align:start position:0% +in most cases in almost all cases to be + + + align:start position:0% +in most cases in almost all cases to be +based on one of two properties of the + + align:start position:0% +based on one of two properties of the + + + align:start position:0% +based on one of two properties of the +male so we want to know what those are + + align:start position:0% +male so we want to know what those are + + + align:start position:0% +male so we want to know what those are +and we want + + align:start position:0% +and we want + + + align:start position:0% +and we want +examples and + + align:start position:0% +examples and + + + align:start position:0% +examples and +uh of each type of uh Choice first of + + align:start position:0% +uh of each type of uh Choice first of + + + align:start position:0% +uh of each type of uh Choice first of +all material + + align:start position:0% +all material + + + align:start position:0% +all material +benefits you know what kind of resources + + align:start position:0% +benefits you know what kind of resources + + + align:start position:0% +benefits you know what kind of resources +does that male is that male capable of + + align:start position:0% +does that male is that male capable of + + + align:start position:0% +does that male is that male capable of +providing why should I choose him so for + + align:start position:0% +providing why should I choose him so for + + + align:start position:0% +providing why should I choose him so for +example in the turn the common + + align:start position:0% +example in the turn the common + + + align:start position:0% +example in the turn the common +turn uh if he wants to mate he better + + align:start position:0% +turn uh if he wants to mate he better + + + align:start position:0% +turn uh if he wants to mate he better +bring her something good to + + align:start position:0% +bring her something good to + + + align:start position:0% +bring her something good to +eat and he brings freshly caught fish to + + align:start position:0% +eat and he brings freshly caught fish to + + + align:start position:0% +eat and he brings freshly caught fish to +the female the bigger the fish the + + align:start position:0% +the female the bigger the fish the + + + align:start position:0% +the female the bigger the fish the +better if he's not such a good forger + + align:start position:0% +better if he's not such a good forger + + + align:start position:0% +better if he's not such a good forger +and doesn't bring her enough she may not + + align:start position:0% +and doesn't bring her enough she may not + + + align:start position:0% +and doesn't bring her enough she may not +mate with + + align:start position:0% +mate with + + + align:start position:0% +mate with +it the black tip hanging + + align:start position:0% +it the black tip hanging + + + align:start position:0% +it the black tip hanging +ply we're going to talk about that + + align:start position:0% +ply we're going to talk about that + + + align:start position:0% +ply we're going to talk about that +next but he always brings food to the + + align:start position:0% +next but he always brings food to the + + + align:start position:0% +next but he always brings food to the +female + + align:start position:0% + + + + align:start position:0% + +also the difference there is that he + + align:start position:0% +also the difference there is that he + + + align:start position:0% +also the difference there is that he +makes with her well she's eating the + + align:start position:0% +makes with her well she's eating the + + + align:start position:0% +makes with her well she's eating the +food there's other material benefits + + align:start position:0% +food there's other material benefits + + + align:start position:0% +food there's other material benefits +that a female can look for let me just + + align:start position:0% +that a female can look for let me just + + + align:start position:0% +that a female can look for let me just +jump to the gold page we can talk about + + align:start position:0% +jump to the gold page we can talk about + + + align:start position:0% +jump to the gold page we can talk about +that now but when he's got more brightly + + align:start position:0% +that now but when he's got more brightly + + + align:start position:0% +that now but when he's got more brightly +colored + + align:start position:0% +colored + + + align:start position:0% +colored +plumage it means he's got more eroids in + + align:start position:0% +plumage it means he's got more eroids in + + + align:start position:0% +plumage it means he's got more eroids in +his body and there have been studies of + + align:start position:0% +his body and there have been studies of + + + align:start position:0% +his body and there have been studies of +that that Scott does review in the + + align:start position:0% +that that Scott does review in the + + + align:start position:0% +that that Scott does review in the +reading + + align:start position:0% +reading + + + align:start position:0% +reading +uh that show that carotenoids high + + align:start position:0% +uh that show that carotenoids high + + + align:start position:0% +uh that show that carotenoids high +levels are cor correlated with strong + + align:start position:0% +levels are cor correlated with strong + + + align:start position:0% +levels are cor correlated with strong +immune systems but it indicates Better + + align:start position:0% +immune systems but it indicates Better + + + align:start position:0% +immune systems but it indicates Better +Health and that has to be because he's + + align:start position:0% +Health and that has to be because he's + + + align:start position:0% +Health and that has to be because he's +getting the carotenoids from his diet so + + align:start position:0% +getting the carotenoids from his diet so + + + align:start position:0% +getting the carotenoids from his diet so +he's a good forager and he's less also + + align:start position:0% +he's a good forager and he's less also + + + align:start position:0% +he's a good forager and he's less also +the studies indicate he's less likely to + + align:start position:0% +the studies indicate he's less likely to + + + align:start position:0% +the studies indicate he's less likely to +have parasites all important if that uh + + align:start position:0% +have parasites all important if that uh + + + align:start position:0% +have parasites all important if that uh +if he's going to be helping the + + align:start position:0% +if he's going to be helping the + + + align:start position:0% +if he's going to be helping the +female let's just show that picture + + align:start position:0% + + + + align:start position:0% + +here there's the gold p and there's a + + align:start position:0% +here there's the gold p and there's a + + + align:start position:0% +here there's the gold p and there's a +the female on the right and the a pretty + + align:start position:0% +the female on the right and the a pretty + + + align:start position:0% +the female on the right and the a pretty +brightly colored gold pinch on the left + + align:start position:0% +brightly colored gold pinch on the left + + + align:start position:0% +brightly colored gold pinch on the left +so he's got quite he's been taking in + + align:start position:0% +so he's got quite he's been taking in + + + align:start position:0% +so he's got quite he's been taking in +carotenoid he's a good + + align:start position:0% + + + + align:start position:0% + +forager + + align:start position:0% + + + + align:start position:0% + +well what other than things other than + + align:start position:0% +well what other than things other than + + + align:start position:0% +well what other than things other than +material benefits well how handsome male + + align:start position:0% +material benefits well how handsome male + + + align:start position:0% +material benefits well how handsome male +is how attractive as he is just by + + align:start position:0% +is how attractive as he is just by + + + align:start position:0% +is how attractive as he is just by +himself I mean if the females let's say + + align:start position:0% +himself I mean if the females let's say + + + align:start position:0% +himself I mean if the females let's say +you let's just take humans the female is + + align:start position:0% +you let's just take humans the female is + + + align:start position:0% +you let's just take humans the female is +wealthy she's already got all the + + align:start position:0% +wealthy she's already got all the + + + align:start position:0% +wealthy she's already got all the +material benefits she's need maybe he + + align:start position:0% +material benefits she's need maybe he + + + align:start position:0% +material benefits she's need maybe he +has servants well then just + + align:start position:0% +has servants well then just + + + align:start position:0% +has servants well then just +choose the best looking strongest male + + align:start position:0% +choose the best looking strongest male + + + align:start position:0% +choose the best looking strongest male +get good jeans just focus on + + align:start position:0% + + + + align:start position:0% + +that can might not work so well because + + align:start position:0% +that can might not work so well because + + + align:start position:0% +that can might not work so well because +she's her Offspring is going to inherit + + align:start position:0% +she's her Offspring is going to inherit + + + align:start position:0% +she's her Offspring is going to inherit +her genes and his so if he's not good at + + align:start position:0% +her genes and his so if he's not good at + + + align:start position:0% +her genes and his so if he's not good at +resource provision her Offspring might + + align:start position:0% +resource provision her Offspring might + + + align:start position:0% +resource provision her Offspring might +not be as well off as she + + align:start position:0% +not be as well off as she + + + align:start position:0% +not be as well off as she +is but both of these things are invol in + + align:start position:0% +is but both of these things are invol in + + + align:start position:0% +is but both of these things are invol in +some species it seems to be totally am + + align:start position:0% +some species it seems to be totally am + + + align:start position:0% +some species it seems to be totally am +Mount material benefits but in most in + + align:start position:0% +Mount material benefits but in most in + + + align:start position:0% +Mount material benefits but in most in +many + + align:start position:0% +many + + + align:start position:0% +many +species other factors of how attractive + + align:start position:0% +species other factors of how attractive + + + align:start position:0% +species other factors of how attractive +the male is will affect the female on + + align:start position:0% +the male is will affect the female on + + + align:start position:0% +the male is will affect the female on +her + + align:start position:0% +her + + + align:start position:0% +her +choice let's go back to the hanging + + align:start position:0% +choice let's go back to the hanging + + + align:start position:0% +choice let's go back to the hanging +flies now + + align:start position:0% +flies now + + + align:start position:0% +flies now +this he I said he brings food to the + + align:start position:0% +this he I said he brings food to the + + + align:start position:0% +this he I said he brings food to the +female and he copulates whether well + + align:start position:0% +female and he copulates whether well + + + align:start position:0% +female and he copulates whether well +she's + + align:start position:0% + + + + align:start position:0% + +eating and if he bring they found in + + align:start position:0% +eating and if he bring they found in + + + align:start position:0% +eating and if he bring they found in +studies that if he brings a larger gift + + align:start position:0% +studies that if he brings a larger gift + + + align:start position:0% +studies that if he brings a larger gift +of food that is a larger + + align:start position:0% +of food that is a larger + + + align:start position:0% +of food that is a larger +insect that she copulates longer with + + align:start position:0% +insect that she copulates longer with + + + align:start position:0% +insect that she copulates longer with +him why because it takes her longer to + + align:start position:0% +him why because it takes her longer to + + + align:start position:0% +him why because it takes her longer to +eat + + align:start position:0% +eat + + + align:start position:0% +eat +it and the longer she copulates the more + + align:start position:0% +it and the longer she copulates the more + + + align:start position:0% +it and the longer she copulates the more +sperm he transfers because it turns out + + align:start position:0% +sperm he transfers because it turns out + + + align:start position:0% +sperm he transfers because it turns out +and this is what the study show we show + + align:start position:0% +and this is what the study show we show + + + align:start position:0% +and this is what the study show we show +you a few graphs here this one was done + + align:start position:0% +you a few graphs here this one was done + + + align:start position:0% +you a few graphs here this one was done +in nature this is done in the lab okay + + align:start position:0% +in nature this is done in the lab okay + + + align:start position:0% +in nature this is done in the lab okay +and so they've plotted there on the + + align:start position:0% +and so they've plotted there on the + + + align:start position:0% +and so they've plotted there on the +ordinate uh in this case the duration of + + align:start position:0% +ordinate uh in this case the duration of + + + align:start position:0% +ordinate uh in this case the duration of +culation + + align:start position:0% +culation + + + align:start position:0% +culation +which is correlated with the amount of + + align:start position:0% +which is correlated with the amount of + + + align:start position:0% +which is correlated with the amount of +sperm being transferred and the the body + + align:start position:0% +sperm being transferred and the the body + + + align:start position:0% +sperm being transferred and the the body +size of the prey that he brings for her + + align:start position:0% +size of the prey that he brings for her + + + align:start position:0% +size of the prey that he brings for her +to eat and look at it the as the prey + + align:start position:0% +to eat and look at it the as the prey + + + align:start position:0% +to eat and look at it the as the prey +gets bigger and bigger up to a certain + + align:start position:0% +gets bigger and bigger up to a certain + + + align:start position:0% +gets bigger and bigger up to a certain +point he mates with him longer and + + align:start position:0% +point he mates with him longer and + + + align:start position:0% +point he mates with him longer and +longer but then it seems to level up and + + align:start position:0% +longer but then it seems to level up and + + + align:start position:0% +longer but then it seems to level up and +it's even clearer in the laboratory + + align:start position:0% +it's even clearer in the laboratory + + + align:start position:0% +it's even clearer in the laboratory +studies + + align:start position:0% +studies + + + align:start position:0% +studies +so the payoff to the male if he brings + + align:start position:0% +so the payoff to the male if he brings + + + align:start position:0% +so the payoff to the male if he brings +larger insects is increased quantity of + + align:start position:0% +larger insects is increased quantity of + + + align:start position:0% +larger insects is increased quantity of +sperm + + align:start position:0% +sperm + + + align:start position:0% +sperm +transferred I mean the ejaculation takes + + align:start position:0% +transferred I mean the ejaculation takes + + + align:start position:0% +transferred I mean the ejaculation takes +it turns out about 20 minutes in this + + align:start position:0% +it turns out about 20 minutes in this + + + align:start position:0% +it turns out about 20 minutes in this +animal so if he finish if she finishes + + align:start position:0% +animal so if he finish if she finishes + + + align:start position:0% +animal so if he finish if she finishes +eating before 20 minutes because he + + align:start position:0% +eating before 20 minutes because he + + + align:start position:0% +eating before 20 minutes because he +didn't bring a large enough insect he + + align:start position:0% +didn't bring a large enough insect he + + + align:start position:0% +didn't bring a large enough insect he +flies off finds another + + align:start position:0% + + + + align:start position:0% + +male so he may not end up being the + + align:start position:0% +male so he may not end up being the + + + align:start position:0% +male so he may not end up being the +father at least not of all the + + align:start position:0% + + + + align:start position:0% + +eggs if there's food left after 20 + + align:start position:0% +eggs if there's food left after 20 + + + align:start position:0% +eggs if there's food left after 20 +minutes well the male gets a doggy bag + + align:start position:0% + + + + align:start position:0% + +okay there's the + + align:start position:0% +okay there's the + + + align:start position:0% +okay there's the +gold okay now I brought this up in the + + align:start position:0% +gold okay now I brought this up in the + + + align:start position:0% +gold okay now I brought this up in the +introduction we talk about Evolution as + + align:start position:0% +introduction we talk about Evolution as + + + align:start position:0% +introduction we talk about Evolution as +survival of the + + align:start position:0% +survival of the + + + align:start position:0% +survival of the +fittest okay question is what do we mean + + align:start position:0% +fittest okay question is what do we mean + + + align:start position:0% +fittest okay question is what do we mean +by by that it's survival of the fittest + + align:start position:0% +by by that it's survival of the fittest + + + align:start position:0% +by by that it's survival of the fittest +then why is it that certain species of + + align:start position:0% +then why is it that certain species of + + + align:start position:0% +then why is it that certain species of +spiders and also occurs in certain + + align:start position:0% +spiders and also occurs in certain + + + align:start position:0% +spiders and also occurs in certain +insects the male is eaten by the female + + align:start position:0% +insects the male is eaten by the female + + + align:start position:0% +insects the male is eaten by the female +in the active population it happens in + + align:start position:0% +in the active population it happens in + + + align:start position:0% +in the active population it happens in +the Australian redback + + align:start position:0% +the Australian redback + + + align:start position:0% +the Australian redback +spider uh and there are some reasons we + + align:start position:0% +spider uh and there are some reasons we + + + align:start position:0% +spider uh and there are some reasons we +can discern for how it's still + + align:start position:0% +can discern for how it's still + + + align:start position:0% +can discern for how it's still +benefiting him but there are other + + align:start position:0% +benefiting him but there are other + + + align:start position:0% +benefiting him but there are other +species too that do that the praying + + align:start position:0% +species too that do that the praying + + + align:start position:0% +species too that do that the praying +mantis is the best + + align:start position:0% +mantis is the best + + + align:start position:0% +mantis is the best +known uh the female tarantula commonly + + align:start position:0% +known uh the female tarantula commonly + + + align:start position:0% +known uh the female tarantula commonly +eats that's the burrowing spider in the + + align:start position:0% +eats that's the burrowing spider in the + + + align:start position:0% +eats that's the burrowing spider in the +American southwest for example they + + align:start position:0% +American southwest for example they + + + align:start position:0% +American southwest for example they +often eat males but it's not always + + align:start position:0% +often eat males but it's not always + + + align:start position:0% +often eat males but it's not always +their mate but it might + + align:start position:0% +their mate but it might + + + align:start position:0% +their mate but it might +be okay so here's the Australian redback + + align:start position:0% +be okay so here's the Australian redback + + + align:start position:0% +be okay so here's the Australian redback +spider see what they look + + align:start position:0% + + + + align:start position:0% + +like these are the reasons why it can + + align:start position:0% +like these are the reasons why it can + + + align:start position:0% +like these are the reasons why it can +still benefit the male in terms of his + + align:start position:0% +still benefit the male in terms of his + + + align:start position:0% +still benefit the male in terms of his +passing on his being first of all he's + + align:start position:0% +passing on his being first of all he's + + + align:start position:0% +passing on his being first of all he's +not + + align:start position:0% +not + + + align:start position:0% +not +likely to survive long enough to find a + + align:start position:0% +likely to survive long enough to find a + + + align:start position:0% +likely to survive long enough to find a +second mid they're shortlived + + align:start position:0% +second mid they're shortlived + + + align:start position:0% +second mid they're shortlived +animal and + + align:start position:0% +animal and + + + align:start position:0% +animal and +again if she eats + + align:start position:0% +again if she eats + + + align:start position:0% +again if she eats +him she's less likely to made again if + + align:start position:0% +him she's less likely to made again if + + + align:start position:0% +him she's less likely to made again if +she's well + + align:start position:0% +she's well + + + align:start position:0% +she's well +fed and more + + align:start position:0% +fed and more + + + align:start position:0% +fed and more +nutrition it can benefit her she's more + + align:start position:0% +nutrition it can benefit her she's more + + + align:start position:0% +nutrition it can benefit her she's more +likely than to have his + + align:start position:0% + + + + align:start position:0% + +offspring you know so what the hell go + + align:start position:0% +offspring you know so what the hell go + + + align:start position:0% +offspring you know so what the hell go +ahead okay here's the praying mantis + + align:start position:0% +ahead okay here's the praying mantis + + + align:start position:0% +ahead okay here's the praying mantis +there you see in the center I put the + + align:start position:0% +there you see in the center I put the + + + align:start position:0% +there you see in the center I put the +center picture of the male and a female + + align:start position:0% +center picture of the male and a female + + + align:start position:0% +center picture of the male and a female +the female is the bigger + + align:start position:0% +the female is the bigger + + + align:start position:0% +the female is the bigger +one + + align:start position:0% +one + + + align:start position:0% +one +uh + + align:start position:0% +uh + + + align:start position:0% +uh +and in the low right there she's eating + + align:start position:0% +and in the low right there she's eating + + + align:start position:0% +and in the low right there she's eating +the + + align:start position:0% +the + + + align:start position:0% +the +mail okay uh this is a study I found uh + + align:start position:0% +mail okay uh this is a study I found uh + + + align:start position:0% +mail okay uh this is a study I found uh +in the literature sexual cannibalism in + + align:start position:0% +in the literature sexual cannibalism in + + + align:start position:0% +in the literature sexual cannibalism in +the praying mansis this particular + + align:start position:0% +the praying mansis this particular + + + align:start position:0% +the praying mansis this particular +praying + + align:start position:0% +praying + + + align:start position:0% +praying +Manis + + align:start position:0% +Manis + + + align:start position:0% +Manis +uh they found that if you the females + + align:start position:0% +uh they found that if you the females + + + align:start position:0% +uh they found that if you the females +are + + align:start position:0% +are + + + align:start position:0% +are +wellfed they usually don't eat the male + + align:start position:0% +wellfed they usually don't eat the male + + + align:start position:0% +wellfed they usually don't eat the male +okay females that are fed more are + + align:start position:0% +okay females that are fed more are + + + align:start position:0% +okay females that are fed more are +heavier and they produce heavier eggs + + align:start position:0% +heavier and they produce heavier eggs + + + align:start position:0% +heavier and they produce heavier eggs +feel more likely to + + align:start position:0% + + + + align:start position:0% + +survive if you feed the females less + + align:start position:0% +survive if you feed the females less + + + align:start position:0% +survive if you feed the females less +these are experiments where they can f + + align:start position:0% +these are experiments where they can f + + + align:start position:0% +these are experiments where they can f +that then the females are much more + + align:start position:0% +that then the females are much more + + + align:start position:0% +that then the females are much more +likely to eat the + + align:start position:0% +likely to eat the + + + align:start position:0% +likely to eat the +male so they did an experiment where + + align:start position:0% +male so they did an experiment where + + + align:start position:0% +male so they did an experiment where +some females were prevented from eating + + align:start position:0% +some females were prevented from eating + + + align:start position:0% +some females were prevented from eating +the male others were not prevented those + + align:start position:0% +the male others were not prevented those + + + align:start position:0% +the male others were not prevented those +that ate the male produced heavier + + align:start position:0% +that ate the male produced heavier + + + align:start position:0% +that ate the male produced heavier +eggs indicating that the cannibalism was + + align:start position:0% +eggs indicating that the cannibalism was + + + align:start position:0% +eggs indicating that the cannibalism was +adaptive for the + + align:start position:0% +adaptive for the + + + align:start position:0% +adaptive for the +female but the + + align:start position:0% +female but the + + + align:start position:0% +female but the +males unlike those spiders we talked + + align:start position:0% +males unlike those spiders we talked + + + align:start position:0% +males unlike those spiders we talked +about the males do try to avoid being + + align:start position:0% +about the males do try to avoid being + + + align:start position:0% +about the males do try to avoid being +eaten indicating from that behavior + + align:start position:0% +eaten indicating from that behavior + + + align:start position:0% +eaten indicating from that behavior +that's probably less adaptive to the + + align:start position:0% +that's probably less adaptive to the + + + align:start position:0% +that's probably less adaptive to the +males that may mean that if he was not + + align:start position:0% +males that may mean that if he was not + + + align:start position:0% +males that may mean that if he was not +eaten maybe he would have a chance to + + align:start position:0% +eaten maybe he would have a chance to + + + align:start position:0% +eaten maybe he would have a chance to +meet with another female that's not + + align:start position:0% +meet with another female that's not + + + align:start position:0% +meet with another female that's not +certain but that's what the study + + align:start position:0% +certain but that's what the study + + + align:start position:0% +certain but that's what the study +indicates + + align:start position:0% +indicates + + + align:start position:0% +indicates +so how adaptive the behavior is can be + + align:start position:0% +so how adaptive the behavior is can be + + + align:start position:0% +so how adaptive the behavior is can be +different for the female and for the + + align:start position:0% +different for the female and for the + + + align:start position:0% +different for the female and for the +male it's clearly adapted for the + + align:start position:0% +male it's clearly adapted for the + + + align:start position:0% +male it's clearly adapted for the +female for the males of some species + + align:start position:0% +female for the males of some species + + + align:start position:0% +female for the males of some species +as we said for the spider probably + + align:start position:0% +as we said for the spider probably + + + align:start position:0% +as we said for the spider probably +benefits him more than hurts him because + + align:start position:0% +benefits him more than hurts him because + + + align:start position:0% +benefits him more than hurts him because +he's not going to live long enough to + + align:start position:0% +he's not going to live long enough to + + + align:start position:0% +he's not going to live long enough to +made again anyway but maybe for some + + align:start position:0% +made again anyway but maybe for some + + + align:start position:0% +made again anyway but maybe for some +like the praying mantis it may not be + + align:start position:0% +like the praying mantis it may not be + + + align:start position:0% +like the praying mantis it may not be +the most adaptive for + + align:start position:0% + + + + align:start position:0% + +him okay so what are the conditions that + + align:start position:0% +him okay so what are the conditions that + + + align:start position:0% +him okay so what are the conditions that +make the female more likely to be the + + align:start position:0% +make the female more likely to be the + + + align:start position:0% +make the female more likely to be the +one that is making the choice of + + align:start position:0% +one that is making the choice of + + + align:start position:0% +one that is making the choice of +mates the studies have tended to focus + + align:start position:0% +mates the studies have tended to focus + + + align:start position:0% +mates the studies have tended to focus +on species with sex Ro reversal that is + + align:start position:0% +on species with sex Ro reversal that is + + + align:start position:0% +on species with sex Ro reversal that is +the males doing all the brood tending + + align:start position:0% +the males doing all the brood tending + + + align:start position:0% +the males doing all the brood tending +and so forth but there are + + align:start position:0% +and so forth but there are + + + align:start position:0% +and so forth but there are +exceptions uh so they look into the + + align:start position:0% +exceptions uh so they look into the + + + align:start position:0% +exceptions uh so they look into the +conditions that seem to facilitate the + + align:start position:0% +conditions that seem to facilitate the + + + align:start position:0% +conditions that seem to facilitate the +evolution of selective mate Choice + + align:start position:0% +evolution of selective mate Choice + + + align:start position:0% +evolution of selective mate Choice +by + + align:start position:0% +by + + + align:start position:0% +by +uh by the male instead of the + + align:start position:0% +uh by the male instead of the + + + align:start position:0% +uh by the male instead of the +female first of all if the male defends + + align:start position:0% +female first of all if the male defends + + + align:start position:0% +female first of all if the male defends +The + + align:start position:0% +The + + + align:start position:0% +The +Nest there's a limit like like in the + + align:start position:0% +Nest there's a limit like like in the + + + align:start position:0% +Nest there's a limit like like in the +stickle backs there there's a limited + + align:start position:0% +stickle backs there there's a limited + + + align:start position:0% +stickle backs there there's a limited +number of eggs he can + + align:start position:0% +number of eggs he can + + + align:start position:0% +number of eggs he can +defend uh he certainly would have a lot + + align:start position:0% +defend uh he certainly would have a lot + + + align:start position:0% +defend uh he certainly would have a lot +of difficulty defending more than one + + align:start position:0% +of difficulty defending more than one + + + align:start position:0% +of difficulty defending more than one +Nest + + align:start position:0% +Nest + + + align:start position:0% +Nest +uh so he can't maximize reproduction + + align:start position:0% +uh so he can't maximize reproduction + + + align:start position:0% +uh so he can't maximize reproduction +just by indiscriminate mating + + align:start position:0% +just by indiscriminate mating + + + align:start position:0% +just by indiscriminate mating +okay so it's in his best interest to + + align:start position:0% +okay so it's in his best interest to + + + align:start position:0% +okay so it's in his best interest to +choose the best female either with the + + align:start position:0% +choose the best female either with the + + + align:start position:0% +choose the best female either with the +most most eggs for that one nest and + + align:start position:0% +most most eggs for that one nest and + + + align:start position:0% +most most eggs for that one nest and +that seems to be true for the stickle + + align:start position:0% +that seems to be true for the stickle + + + align:start position:0% +that seems to be true for the stickle +bags uh or other signs that it's a male + + align:start position:0% +bags uh or other signs that it's a male + + + align:start position:0% +bags uh or other signs that it's a male +a female that's producing perhaps + + align:start position:0% +a female that's producing perhaps + + + align:start position:0% +a female that's producing perhaps +heavier eggs and so forth they'd have a + + align:start position:0% +heavier eggs and so forth they'd have a + + + align:start position:0% +heavier eggs and so forth they'd have a +better chance of + + align:start position:0% +better chance of + + + align:start position:0% +better chance of +survival and if there's many more + + align:start position:0% +survival and if there's many more + + + align:start position:0% +survival and if there's many more +females than males and that's true of + + align:start position:0% +females than males and that's true of + + + align:start position:0% +females than males and that's true of +some species then mate choice is more + + align:start position:0% +some species then mate choice is more + + + align:start position:0% +some species then mate choice is more +likely male male males making the choice + + align:start position:0% +likely male male males making the choice + + + align:start position:0% +likely male male males making the choice +is more likely + + align:start position:0% +is more likely + + + align:start position:0% +is more likely +especially if the male's also in charge + + align:start position:0% +especially if the male's also in charge + + + align:start position:0% +especially if the male's also in charge +of + + align:start position:0% + + + + align:start position:0% + +an + + align:start position:0% + + + + align:start position:0% + +okay now you also have variations in + + align:start position:0% +okay now you also have variations in + + + align:start position:0% +okay now you also have variations in +mating strategies even within a species + + align:start position:0% +mating strategies even within a species + + + align:start position:0% +mating strategies even within a species +so that's what I want to talk about here + + align:start position:0% +so that's what I want to talk about here + + + align:start position:0% +so that's what I want to talk about here +the different male mating + + align:start position:0% +the different male mating + + + align:start position:0% +the different male mating +strategies I ask for example of how in + + align:start position:0% +strategies I ask for example of how in + + + align:start position:0% +strategies I ask for example of how in +some species different individual males + + align:start position:0% +some species different individual males + + + align:start position:0% +some species different individual males +adopt very different mating Str strategy + + align:start position:0% +adopt very different mating Str strategy + + + align:start position:0% +adopt very different mating Str strategy +even + + align:start position:0% +even + + + align:start position:0% +even +though + + align:start position:0% +though + + + align:start position:0% +though +uh these males may all have the same + + align:start position:0% +uh these males may all have the same + + + align:start position:0% +uh these males may all have the same +genes okay and these are the examples + + align:start position:0% +genes okay and these are the examples + + + align:start position:0% +genes okay and these are the examples +we'll talk about the scar of beetles + + align:start position:0% +we'll talk about the scar of beetles + + + align:start position:0% +we'll talk about the scar of beetles +some of which are very big and they have + + align:start position:0% +some of which are very big and they have + + + align:start position:0% +some of which are very big and they have +horns some of them are smaller and don't + + align:start position:0% +horns some of them are smaller and don't + + + align:start position:0% +horns some of them are smaller and don't +have + + align:start position:0% +have + + + align:start position:0% +have +horns so it looks like those big ones + + align:start position:0% +horns so it looks like those big ones + + + align:start position:0% +horns so it looks like those big ones +are a lot more + + align:start position:0% +are a lot more + + + align:start position:0% +are a lot more +fit we want to know you know what do the + + align:start position:0% +fit we want to know you know what do the + + + align:start position:0% +fit we want to know you know what do the +smaller ones do you find the same + + align:start position:0% +smaller ones do you find the same + + + align:start position:0% +smaller ones do you find the same +problem in toads because some of them + + align:start position:0% +problem in toads because some of them + + + align:start position:0% +problem in toads because some of them +are very big and can croak loudly and + + align:start position:0% +are very big and can croak loudly and + + + align:start position:0% +are very big and can croak loudly and +attract females some are not so much + + align:start position:0% +attract females some are not so much + + + align:start position:0% +attract females some are not so much +smaller same is true of iguanas we saw + + align:start position:0% +smaller same is true of iguanas we saw + + + align:start position:0% +smaller same is true of iguanas we saw +in the picture earlier we were talking + + align:start position:0% +in the picture earlier we were talking + + + align:start position:0% +in the picture earlier we were talking +about foraging strategies you found out + + align:start position:0% +about foraging strategies you found out + + + align:start position:0% +about foraging strategies you found out +the foraging strategies were quite + + align:start position:0% +the foraging strategies were quite + + + align:start position:0% +the foraging strategies were quite +different in the large iguanas and the + + align:start position:0% +different in the large iguanas and the + + + align:start position:0% +different in the large iguanas and the +smaller + + align:start position:0% +smaller + + + align:start position:0% +smaller +ones they have a more unusual mating + + align:start position:0% +ones they have a more unusual mating + + + align:start position:0% +ones they have a more unusual mating +strategy so first of all the scarab + + align:start position:0% +strategy so first of all the scarab + + + align:start position:0% +strategy so first of all the scarab +beetles they've evolved two distinct + + align:start position:0% +beetles they've evolved two distinct + + + align:start position:0% +beetles they've evolved two distinct +morphologies as I mentioned the smaller + + align:start position:0% +morphologies as I mentioned the smaller + + + align:start position:0% +morphologies as I mentioned the smaller +ones have no harms but they're more + + align:start position:0% +ones have no harms but they're more + + + align:start position:0% +ones have no harms but they're more +agile they're + + align:start position:0% +agile they're + + + align:start position:0% +agile they're +quicker so they can some very often + + align:start position:0% +quicker so they can some very often + + + align:start position:0% +quicker so they can some very often +they're able the male is defending they + + align:start position:0% +they're able the male is defending they + + + align:start position:0% +they're able the male is defending they +have underground nest and the male will + + align:start position:0% +have underground nest and the male will + + + align:start position:0% +have underground nest and the male will +defend Nest he will try to keep other + + align:start position:0% +defend Nest he will try to keep other + + + align:start position:0% +defend Nest he will try to keep other +Mal from getting it his eggs okay or to + + align:start position:0% +Mal from getting it his eggs okay or to + + + align:start position:0% +Mal from getting it his eggs okay or to +getting at the female who is there in + + align:start position:0% +getting at the female who is there in + + + align:start position:0% +getting at the female who is there in +the tunnel + + align:start position:0% +the tunnel + + + align:start position:0% +the tunnel +but those small males are often able to + + align:start position:0% +but those small males are often able to + + + align:start position:0% +but those small males are often able to +get past the male the big male avoid his + + align:start position:0% +get past the male the big male avoid his + + + align:start position:0% +get past the male the big male avoid his +horns and get to the female now he's got + + align:start position:0% +horns and get to the female now he's got + + + align:start position:0% +horns and get to the female now he's got +to be + + align:start position:0% +to be + + + align:start position:0% +to be +quick because why does m just turn + + align:start position:0% +quick because why does m just turn + + + align:start position:0% +quick because why does m just turn +around and get him well he's so he's so + + align:start position:0% +around and get him well he's so he's so + + + align:start position:0% +around and get him well he's so he's so +big with these big wide horns he he + + align:start position:0% +big with these big wide horns he he + + + align:start position:0% +big with these big wide horns he he +usually has to come clear out of the + + align:start position:0% +usually has to come clear out of the + + + align:start position:0% +usually has to come clear out of the +tunnel and turn + + align:start position:0% +tunnel and turn + + + align:start position:0% +tunnel and turn +around well that gives that small male + + align:start position:0% +around well that gives that small male + + + align:start position:0% +around well that gives that small male +just time + + align:start position:0% +just time + + + align:start position:0% +just time +okay so sneak a quick one with the + + align:start position:0% +okay so sneak a quick one with the + + + align:start position:0% +okay so sneak a quick one with the +female before he can + + align:start position:0% +female before he can + + + align:start position:0% +female before he can +attack and then he just has the problem + + align:start position:0% +attack and then he just has the problem + + + align:start position:0% +attack and then he just has the problem +of getting past him because he will come + + align:start position:0% +of getting past him because he will come + + + align:start position:0% +of getting past him because he will come +in now with a small Marine iguana it's + + align:start position:0% +in now with a small Marine iguana it's + + + align:start position:0% +in now with a small Marine iguana it's +even more + + align:start position:0% +even more + + + align:start position:0% +even more +interesting the copulation normally + + align:start position:0% +interesting the copulation normally + + + align:start position:0% +interesting the copulation normally +requires several minutes for the male to + + align:start position:0% +requires several minutes for the male to + + + align:start position:0% +requires several minutes for the male to +ejaculate uh but these small iguanas + + align:start position:0% +ejaculate uh but these small iguanas + + + align:start position:0% +ejaculate uh but these small iguanas +have the ability to ejaculate in advance + + align:start position:0% +have the ability to ejaculate in advance + + + align:start position:0% +have the ability to ejaculate in advance +and store the sperm in a Groove in their + + align:start position:0% +and store the sperm in a Groove in their + + + align:start position:0% +and store the sperm in a Groove in their +penis so he only needs a very brief + + align:start position:0% +penis so he only needs a very brief + + + align:start position:0% +penis so he only needs a very brief +population deposits the sperm and gets + + align:start position:0% +population deposits the sperm and gets + + + align:start position:0% +population deposits the sperm and gets +out of + + align:start position:0% +out of + + + align:start position:0% +out of +it okay and of course the male the + + align:start position:0% +it okay and of course the male the + + + align:start position:0% +it okay and of course the male the +bigger male will be trying to prevent + + align:start position:0% +bigger male will be trying to prevent + + + align:start position:0% +bigger male will be trying to prevent +him from mating so but so they've + + align:start position:0% +him from mating so but so they've + + + align:start position:0% +him from mating so but so they've +evolved with trategy they don't need so + + align:start position:0% +evolved with trategy they don't need so + + + align:start position:0% +evolved with trategy they don't need so +much + + align:start position:0% +much + + + align:start position:0% +much +time so both the large and the small + + align:start position:0% +time so both the large and the small + + + align:start position:0% +time so both the large and the small +them males are able to + + align:start position:0% + + + + align:start position:0% + +M + + align:start position:0% +M + + + align:start position:0% +M +okay let's talk about the various mating + + align:start position:0% +okay let's talk about the various mating + + + align:start position:0% +okay let's talk about the various mating +systems and why there are so many + + align:start position:0% +systems and why there are so many + + + align:start position:0% +systems and why there are so many +different + + align:start position:0% + + + + align:start position:0% + +ones and here we mean bigy polyandry + + align:start position:0% +ones and here we mean bigy polyandry + + + align:start position:0% +ones and here we mean bigy polyandry +bandry U this this was studied + + align:start position:0% +bandry U this this was studied + + + align:start position:0% +bandry U this this was studied +extensively in Birds by Nick Davies + + align:start position:0% +extensively in Birds by Nick Davies + + + align:start position:0% +extensively in Birds by Nick Davies +uh most of his studies were done on the + + align:start position:0% +uh most of his studies were done on the + + + align:start position:0% +uh most of his studies were done on the +reproductive behavior of the dunck it's + + align:start position:0% +reproductive behavior of the dunck it's + + + align:start position:0% +reproductive behavior of the dunck it's +a small European song bird the Hedge + + align:start position:0% +a small European song bird the Hedge + + + align:start position:0% +a small European song bird the Hedge +Sparrow is its common + + align:start position:0% + + + + align:start position:0% + +name and they found all the different + + align:start position:0% +name and they found all the different + + + align:start position:0% +name and they found all the different +varieties of mating strategy in this + + align:start position:0% +varieties of mating strategy in this + + + align:start position:0% +varieties of mating strategy in this +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +one species of bird and this is the way + + align:start position:0% +one species of bird and this is the way + + + align:start position:0% +one species of bird and this is the way +he + + align:start position:0% +he + + + align:start position:0% +he +summarized uh that issue he said we + + align:start position:0% +summarized uh that issue he said we + + + align:start position:0% +summarized uh that issue he said we +should view The Mating Game not as a + + align:start position:0% +should view The Mating Game not as a + + + align:start position:0% +should view The Mating Game not as a +Cooper operation between the Sexes but + + align:start position:0% +Cooper operation between the Sexes but + + + align:start position:0% +Cooper operation between the Sexes but +as a conflict resulting in a compromise + + align:start position:0% +as a conflict resulting in a compromise + + + align:start position:0% +as a conflict resulting in a compromise +in the interests of one or both of + + align:start position:0% + + + + align:start position:0% + +them it doesn't sound + + align:start position:0% +them it doesn't sound + + + align:start position:0% +them it doesn't sound +like a lyric love poetry does + + align:start position:0% +like a lyric love poetry does + + + align:start position:0% +like a lyric love poetry does +it no we're talking about + + align:start position:0% +it no we're talking about + + + align:start position:0% +it no we're talking about +Evolution okay and yes it has affected + + align:start position:0% +Evolution okay and yes it has affected + + + align:start position:0% +Evolution okay and yes it has affected +humans very + + align:start position:0% +humans very + + + align:start position:0% +humans very +strongly here's the basic mating systems + + align:start position:0% + + + + align:start position:0% + +monogamy you all know what monogamy is + + align:start position:0% +monogamy you all know what monogamy is + + + align:start position:0% +monogamy you all know what monogamy is +but we have to distinguish between + + align:start position:0% +but we have to distinguish between + + + align:start position:0% +but we have to distinguish between +social monogamy and genetic + + align:start position:0% +social monogamy and genetic + + + align:start position:0% +social monogamy and genetic +monogamy what's the + + align:start position:0% +monogamy what's the + + + align:start position:0% +monogamy what's the +difference social monogamy means one the + + align:start position:0% +difference social monogamy means one the + + + align:start position:0% +difference social monogamy means one the +female lives with the same + + align:start position:0% +female lives with the same + + + align:start position:0% +female lives with the same +male all the time the same male these + + align:start position:0% +male all the time the same male these + + + align:start position:0% +male all the time the same male these +monogamy genetic monogamy + + align:start position:0% +monogamy genetic monogamy + + + align:start position:0% +monogamy genetic monogamy +as who fathers are children and + + align:start position:0% +as who fathers are children and + + + align:start position:0% +as who fathers are children and +here in many cases they thought social + + align:start position:0% +here in many cases they thought social + + + align:start position:0% +here in many cases they thought social +monogamy always meant genetic monogamy + + align:start position:0% +monogamy always meant genetic monogamy + + + align:start position:0% +monogamy always meant genetic monogamy +but now we have the ability to look at + + align:start position:0% +but now we have the ability to look at + + + align:start position:0% +but now we have the ability to look at +the DNA and we found out we find out + + align:start position:0% +the DNA and we found out we find out + + + align:start position:0% +the DNA and we found out we find out +that that's often not true not for + + align:start position:0% +that that's often not true not for + + + align:start position:0% +that that's often not true not for +humans not for Birds but these are the + + align:start position:0% +humans not for Birds but these are the + + + align:start position:0% +humans not for Birds but these are the +where most of the studies have been done + + align:start position:0% +where most of the studies have been done + + + align:start position:0% +where most of the studies have been done +especially + + align:start position:0% +especially + + + align:start position:0% +especially +Birds + + align:start position:0% +Birds + + + align:start position:0% +Birds +okay polygyny that's when you + + align:start position:0% +okay polygyny that's when you + + + align:start position:0% +okay polygyny that's when you +have one male mating with more than one + + align:start position:0% + + + + align:start position:0% + +female and + + align:start position:0% +female and + + + align:start position:0% +female and +uh you have the resource-based polygyny + + align:start position:0% +uh you have the resource-based polygyny + + + align:start position:0% +uh you have the resource-based polygyny +WHERE females + + align:start position:0% +WHERE females + + + align:start position:0% +WHERE females +chose by the value of the territory + + align:start position:0% +chose by the value of the territory + + + align:start position:0% +chose by the value of the territory +that's done in the + + align:start position:0% +that's done in the + + + align:start position:0% +that's done in the +Iguana the pl P fly + + align:start position:0% +Iguana the pl P fly + + + align:start position:0% +Iguana the pl P fly +catcher + + align:start position:0% +catcher + + + align:start position:0% +catcher +uh + + align:start position:0% +uh + + + align:start position:0% +uh +and there you find interesting choices a + + align:start position:0% +and there you find interesting choices a + + + align:start position:0% +and there you find interesting choices a +female faced with a choice between a + + align:start position:0% +female faced with a choice between a + + + align:start position:0% +female faced with a choice between a +single male and a male that already has + + align:start position:0% +single male and a male that already has + + + align:start position:0% +single male and a male that already has +one female will often choose the male + + align:start position:0% +one female will often choose the male + + + align:start position:0% +one female will often choose the male +that already has another + + align:start position:0% +that already has another + + + align:start position:0% +that already has another +female + + align:start position:0% +female + + + align:start position:0% +female +why better + + align:start position:0% +why better + + + align:start position:0% +why better +territory he's looking at the whole + + align:start position:0% +territory he's looking at the whole + + + align:start position:0% +territory he's looking at the whole +picture if that male is capable because + + align:start position:0% +picture if that male is capable because + + + align:start position:0% +picture if that male is capable because +of his territory the value of his + + align:start position:0% +of his territory the value of his + + + align:start position:0% +of his territory the value of his +territory of the mating with more than + + align:start position:0% +territory of the mating with more than + + + align:start position:0% +territory of the mating with more than +one female he's happy to join the + + align:start position:0% + + + + align:start position:0% + +family female defense + + align:start position:0% +family female defense + + + align:start position:0% +family female defense +polygyny well you know what that is the + + align:start position:0% +polygyny well you know what that is the + + + align:start position:0% +polygyny well you know what that is the +Harum if a male can defend more + + align:start position:0% + + + + align:start position:0% + +females as you know some sea + + align:start position:0% +females as you know some sea + + + align:start position:0% +females as you know some sea +mammal marine mammals do that sea + + align:start position:0% +mammal marine mammals do that sea + + + align:start position:0% +mammal marine mammals do that sea +lions seals they will have a large + + align:start position:0% +lions seals they will have a large + + + align:start position:0% +lions seals they will have a large +number of the the male will the large + + align:start position:0% +number of the the male will the large + + + align:start position:0% +number of the the male will the large +male will have a herum but they have to + + align:start position:0% +male will have a herum but they have to + + + align:start position:0% +male will have a herum but they have to +be strong enough and quick enough to + + align:start position:0% +be strong enough and quick enough to + + + align:start position:0% +be strong enough and quick enough to +defend that those females and that will + + align:start position:0% +defend that those females and that will + + + align:start position:0% +defend that those females and that will +limit the + + align:start position:0% +limit the + + + align:start position:0% +limit the +size of their + + align:start position:0% + + + + align:start position:0% + +uh their + + align:start position:0% +uh their + + + align:start position:0% +uh their +group but that's female defense poig and + + align:start position:0% +group but that's female defense poig and + + + align:start position:0% +group but that's female defense poig and +then Le based poyy we'll bring that up + + align:start position:0% +then Le based poyy we'll bring that up + + + align:start position:0% +then Le based poyy we'll bring that up +again at the end there's about 200 + + align:start position:0% +again at the end there's about 200 + + + align:start position:0% +again at the end there's about 200 +species that have Lex that's occurs in + + align:start position:0% +species that have Lex that's occurs in + + + align:start position:0% +species that have Lex that's occurs in +the snipe it conerts in fruit fruit + + align:start position:0% +the snipe it conerts in fruit fruit + + + align:start position:0% +the snipe it conerts in fruit fruit +flies and various Birds this is when the + + align:start position:0% +flies and various Birds this is when the + + + align:start position:0% +flies and various Birds this is when the +female chooses among males that are + + align:start position:0% +female chooses among males that are + + + align:start position:0% +female chooses among males that are +lined up in front of her that's the Leck + + align:start position:0% +lined up in front of her that's the Leck + + + align:start position:0% +lined up in front of her that's the Leck +it's + + align:start position:0% +it's + + + align:start position:0% +it's +like Nature's single bar you know or the + + align:start position:0% +like Nature's single bar you know or the + + + align:start position:0% +like Nature's single bar you know or the +female comes in and she can get + + align:start position:0% +female comes in and she can get + + + align:start position:0% +female comes in and she can get +everything done a whole all the whole + + align:start position:0% +everything done a whole all the whole + + + align:start position:0% +everything done a whole all the whole +group of females can deal with it at + + align:start position:0% +group of females can deal with it at + + + align:start position:0% +group of females can deal with it at +once because the males are all there and + + align:start position:0% +once because the males are all there and + + + align:start position:0% +once because the males are all there and +there's various reasons why Lex form + + align:start position:0% +there's various reasons why Lex form + + + align:start position:0% +there's various reasons why Lex form +we'll bring that up in the end but + + align:start position:0% +we'll bring that up in the end but + + + align:start position:0% +we'll bring that up in the end but +that's another kind of polyandry because + + align:start position:0% +that's another kind of polyandry because + + + align:start position:0% +that's another kind of polyandry because +uh oh + + align:start position:0% +uh oh + + + align:start position:0% +uh oh +sorry polygyny because the male of and + + align:start position:0% +sorry polygyny because the male of and + + + align:start position:0% +sorry polygyny because the male of and +only one male doing almost all the + + align:start position:0% + + + + align:start position:0% + +ma you know the the Hot Shot + + align:start position:0% + + + + align:start position:0% + +male and then polyandry where we + + align:start position:0% +male and then polyandry where we + + + align:start position:0% +male and then polyandry where we +mentioned the sand Piper where the + + align:start position:0% +mentioned the sand Piper where the + + + align:start position:0% +mentioned the sand Piper where the +female will leave the first male and + + align:start position:0% +female will leave the first male and + + + align:start position:0% +female will leave the first male and +have a second brood of eggs so he's + + align:start position:0% +have a second brood of eggs so he's + + + align:start position:0% +have a second brood of eggs so he's +mating with at least two + + align:start position:0% +mating with at least two + + + align:start position:0% +mating with at least two +males + + align:start position:0% +males + + + align:start position:0% +males +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +uh but this occurs in various other + + align:start position:0% +uh but this occurs in various other + + + align:start position:0% +uh but this occurs in various other +birds as + + align:start position:0% +birds as + + + align:start position:0% +birds as +well and it occurs in some + + align:start position:0% +well and it occurs in some + + + align:start position:0% +well and it occurs in some +uh it occurs in some human + + align:start position:0% +uh it occurs in some human + + + align:start position:0% +uh it occurs in some human +groups and then pigan andry where you + + align:start position:0% +groups and then pigan andry where you + + + align:start position:0% +groups and then pigan andry where you +have more than one male and one more + + align:start position:0% +have more than one male and one more + + + align:start position:0% +have more than one male and one more +than one female + + align:start position:0% +than one female + + + align:start position:0% +than one female +okay and you have all of these mating + + align:start position:0% +okay and you have all of these mating + + + align:start position:0% +okay and you have all of these mating +systems in the dunck and I would like + + align:start position:0% +systems in the dunck and I would like + + + align:start position:0% +systems in the dunck and I would like +you to I underlined here figure 83 + + align:start position:0% +you to I underlined here figure 83 + + + align:start position:0% +you to I underlined here figure 83 +because I want you to study that um I + + align:start position:0% +because I want you to study that um I + + + align:start position:0% +because I want you to study that um I +didn't get a copy of it I'm sorry I + + align:start position:0% +didn't get a copy of it I'm sorry I + + + align:start position:0% +didn't get a copy of it I'm sorry I +actually have a disc I think that has + + align:start position:0% +actually have a disc I think that has + + + align:start position:0% +actually have a disc I think that has +these but it's an interesting + + align:start position:0% +these but it's an interesting + + + align:start position:0% +these but it's an interesting +figure + + align:start position:0% + + + + align:start position:0% + +uh and in it he shows the four kinds of + + align:start position:0% +uh and in it he shows the four kinds of + + + align:start position:0% +uh and in it he shows the four kinds of +mating and and he shows you know + + align:start position:0% + + + + align:start position:0% + +how what + + align:start position:0% +how what + + + align:start position:0% +how what +happens if the + + align:start position:0% +happens if the + + + align:start position:0% +happens if the +female you know leaves the monogamous + + align:start position:0% +female you know leaves the monogamous + + + align:start position:0% +female you know leaves the monogamous +situation how can she benefit and what + + align:start position:0% +situation how can she benefit and what + + + align:start position:0% +situation how can she benefit and what +happens if the male leaves how can they + + align:start position:0% +happens if the male leaves how can they + + + align:start position:0% +happens if the male leaves how can they +benefit and they've collected data on + + align:start position:0% +benefit and they've collected data on + + + align:start position:0% +benefit and they've collected data on +this and then those groups uh what are + + align:start position:0% +this and then those groups uh what are + + + align:start position:0% +this and then those groups uh what are +the selective factors that make them + + align:start position:0% +the selective factors that make them + + + align:start position:0% +the selective factors that make them +make them + + align:start position:0% + + + + align:start position:0% + +uh become p danders in the last one and + + align:start position:0% +uh become p danders in the last one and + + + align:start position:0% +uh become p danders in the last one and +the data as I read it there I think + + align:start position:0% +the data as I read it there I think + + + align:start position:0% +the data as I read it there I think +there's a mistake in the figure it + + align:start position:0% +there's a mistake in the figure it + + + align:start position:0% +there's a mistake in the figure it +doesn't fully make sense but most of it + + align:start position:0% +doesn't fully make sense but most of it + + + align:start position:0% +doesn't fully make sense but most of it +makes very good sense and these Studies + + align:start position:0% +makes very good sense and these Studies + + + align:start position:0% +makes very good sense and these Studies +by + + align:start position:0% +by + + + align:start position:0% +by +uh + + align:start position:0% + + + + align:start position:0% + +uh this + + align:start position:0% +uh this + + + align:start position:0% +uh this +guy + + align:start position:0% +guy + + + align:start position:0% +guy +Davies uh I believe it was his group + + align:start position:0% +Davies uh I believe it was his group + + + align:start position:0% +Davies uh I believe it was his group +that collected that data but I want you + + align:start position:0% +that collected that data but I want you + + + align:start position:0% +that collected that data but I want you +to look at that because it shows + + align:start position:0% +to look at that because it shows + + + align:start position:0% +to look at that because it shows +how the counts of mating of genetic + + align:start position:0% +how the counts of mating of genetic + + + align:start position:0% +how the counts of mating of genetic +success can vary just depending on the + + align:start position:0% +success can vary just depending on the + + + align:start position:0% +success can vary just depending on the +mating system and sometimes moving to + + align:start position:0% +mating system and sometimes moving to + + + align:start position:0% +mating system and sometimes moving to +another mating system affects one sex + + align:start position:0% +another mating system affects one sex + + + align:start position:0% +another mating system affects one sex +more than + + align:start position:0% +more than + + + align:start position:0% +more than +another and that's what's LED because + + align:start position:0% +another and that's what's LED because + + + align:start position:0% +another and that's what's LED because +all of these occur in the dunck it it + + align:start position:0% +all of these occur in the dunck it it + + + align:start position:0% +all of these occur in the dunck it it +was a good species to study for + + align:start position:0% +was a good species to study for + + + align:start position:0% +was a good species to study for +that and he certainly did find different + + align:start position:0% +that and he certainly did find different + + + align:start position:0% +that and he certainly did find different +benefits to male and to female if they + + align:start position:0% +benefits to male and to female if they + + + align:start position:0% +benefits to male and to female if they +move to another mating + + align:start position:0% +move to another mating + + + align:start position:0% +move to another mating +system okay so what makes monogamy + + align:start position:0% +system okay so what makes monogamy + + + align:start position:0% +system okay so what makes monogamy +happen there must be some situations + + align:start position:0% +happen there must be some situations + + + align:start position:0% +happen there must be some situations +that favor + + align:start position:0% +that favor + + + align:start position:0% +that favor +monogamy and uh these are specific + + align:start position:0% +monogamy and uh these are specific + + + align:start position:0% +monogamy and uh these are specific +examples of monogamous animals the + + align:start position:0% +examples of monogamous animals the + + + align:start position:0% +examples of monogamous animals the +Siberian hamster the jarian hamster + + align:start position:0% +Siberian hamster the jarian hamster + + + align:start position:0% +Siberian hamster the jarian hamster +bopus uh um it lives in nature in under + + align:start position:0% +bopus uh um it lives in nature in under + + + align:start position:0% +bopus uh um it lives in nature in under +very harsh conditions it's very cold + + align:start position:0% +very harsh conditions it's very cold + + + align:start position:0% +very harsh conditions it's very cold +food is limited uh foraging is + + align:start position:0% +food is limited uh foraging is + + + align:start position:0% +food is limited uh foraging is +difficult it makes it unlikely that pups + + align:start position:0% +difficult it makes it unlikely that pups + + + align:start position:0% +difficult it makes it unlikely that pups +could survive unless they have at least + + align:start position:0% +could survive unless they have at least + + + align:start position:0% +could survive unless they have at least +two + + align:start position:0% +two + + + align:start position:0% +two +caregivers so that's a very good + + align:start position:0% +caregivers so that's a very good + + + align:start position:0% +caregivers so that's a very good +reason if neither of them can + + align:start position:0% +reason if neither of them can + + + align:start position:0% +reason if neither of them can +make if they have only there's only one + + align:start position:0% +make if they have only there's only one + + + align:start position:0% +make if they have only there's only one +uh just if there's only one of them + + align:start position:0% +uh just if there's only one of them + + + align:start position:0% +uh just if there's only one of them +female can't do it by herself so it's + + align:start position:0% +female can't do it by herself so it's + + + align:start position:0% +female can't do it by herself so it's +not good for the male either because he + + align:start position:0% +not good for the male either because he + + + align:start position:0% +not good for the male either because he +can M with her but if he doesn't stay to + + align:start position:0% +can M with her but if he doesn't stay to + + + align:start position:0% +can M with her but if he doesn't stay to +take care of the young they won't + + align:start position:0% +take care of the young they won't + + + align:start position:0% +take care of the young they won't +survive you know and they've collected + + align:start position:0% +survive you know and they've collected + + + align:start position:0% +survive you know and they've collected +data on this and this appears to be the + + align:start position:0% +data on this and this appears to be the + + + align:start position:0% +data on this and this appears to be the +case with Siberian hamsters the deep sea + + align:start position:0% +case with Siberian hamsters the deep sea + + + align:start position:0% +case with Siberian hamsters the deep sea +anglerfish that's a different problem + + align:start position:0% +anglerfish that's a different problem + + + align:start position:0% +anglerfish that's a different problem +he's one of these sit and weight + + align:start position:0% +he's one of these sit and weight + + + align:start position:0% +he's one of these sit and weight +Predators he sits in one place until you + + align:start position:0% +Predators he sits in one place until you + + + align:start position:0% +Predators he sits in one place until you +know uh something he can eat comes along + + align:start position:0% +know uh something he can eat comes along + + + align:start position:0% +know uh something he can eat comes along +and he hardly ever sees another + + align:start position:0% +and he hardly ever sees another + + + align:start position:0% +and he hardly ever sees another +anglerfish so when he does the male + + align:start position:0% +anglerfish so when he does the male + + + align:start position:0% +anglerfish so when he does the male +attaches himself to the female as a kind + + align:start position:0% +attaches himself to the female as a kind + + + align:start position:0% +attaches himself to the female as a kind +of + + align:start position:0% +of + + + align:start position:0% +of +parasite otherwise you know he's not + + align:start position:0% +parasite otherwise you know he's not + + + align:start position:0% +parasite otherwise you know he's not +likely to see another female might too + + align:start position:0% +likely to see another female might too + + + align:start position:0% +likely to see another female might too +much time may go by you may never have + + align:start position:0% +much time may go by you may never have + + + align:start position:0% +much time may go by you may never have +another chance so it's a good reason to + + align:start position:0% +another chance so it's a good reason to + + + align:start position:0% +another chance so it's a good reason to +for a peculiar kind of + + align:start position:0% + + + + align:start position:0% + +monogamy but monogamy isn't as common as + + align:start position:0% +monogamy but monogamy isn't as common as + + + align:start position:0% +monogamy but monogamy isn't as common as +other mating + + align:start position:0% +other mating + + + align:start position:0% +other mating +strategies in many species they have a + + align:start position:0% +strategies in many species they have a + + + align:start position:0% +strategies in many species they have a +kind of monogamy but it's not that the + + align:start position:0% +kind of monogamy but it's not that the + + + align:start position:0% +kind of monogamy but it's not that the +female wouldn't go off and mate with + + align:start position:0% +female wouldn't go off and mate with + + + align:start position:0% +female wouldn't go off and mate with +another male so the male simply + + align:start position:0% +another male so the male simply + + + align:start position:0% +another male so the male simply +practices mate + + align:start position:0% +practices mate + + + align:start position:0% +practices mate +guarding he drives away he watches her + + align:start position:0% +guarding he drives away he watches her + + + align:start position:0% +guarding he drives away he watches her +and drives away other males if they try + + align:start position:0% +and drives away other males if they try + + + align:start position:0% +and drives away other males if they try +to mate with her he watches her he + + align:start position:0% +to mate with her he watches her he + + + align:start position:0% +to mate with her he watches her he +guards her until she lays the + + align:start position:0% + + + + align:start position:0% + +eggs he wants to make make sure that + + align:start position:0% +eggs he wants to make make sure that + + + align:start position:0% +eggs he wants to make make sure that +it's his sperm the only sperm that + + align:start position:0% +it's his sperm the only sperm that + + + align:start position:0% +it's his sperm the only sperm that +inseminate those + + align:start position:0% + + + + align:start position:0% + +eggs so that reduces the chance of + + align:start position:0% +eggs so that reduces the chance of + + + align:start position:0% +eggs so that reduces the chance of +extrair copulations and it occurs in + + align:start position:0% +extrair copulations and it occurs in + + + align:start position:0% +extrair copulations and it occurs in +many species as we will see when we + + align:start position:0% +many species as we will see when we + + + align:start position:0% +many species as we will see when we +study + + align:start position:0% + + + + align:start position:0% + +sociobiology so what strategies do you + + align:start position:0% +sociobiology so what strategies do you + + + align:start position:0% +sociobiology so what strategies do you +have other than mate guarding to enforce + + align:start position:0% +have other than mate guarding to enforce + + + align:start position:0% +have other than mate guarding to enforce +a a kind of + + align:start position:0% +a a kind of + + + align:start position:0% +a a kind of +monogamy so in other words it may not + + align:start position:0% +monogamy so in other words it may not + + + align:start position:0% +monogamy so in other words it may not +always be the natural + + align:start position:0% +always be the natural + + + align:start position:0% +always be the natural +preference especially of the female she + + align:start position:0% +preference especially of the female she + + + align:start position:0% +preference especially of the female she +might readily mate with another male so + + align:start position:0% +might readily mate with another male so + + + align:start position:0% +might readily mate with another male so +the males have evolved strategies other + + align:start position:0% +the males have evolved strategies other + + + align:start position:0% +the males have evolved strategies other +than mateu guarding for example in there + + align:start position:0% +than mateu guarding for example in there + + + align:start position:0% +than mateu guarding for example in there +are crabs in which the male's ejaculate + + align:start position:0% +are crabs in which the male's ejaculate + + + align:start position:0% +are crabs in which the male's ejaculate +forms a + + align:start position:0% +forms a + + + align:start position:0% +forms a +plug that makes it almost impossible for + + align:start position:0% +plug that makes it almost impossible for + + + align:start position:0% +plug that makes it almost impossible for +another male to get any sperm in + + align:start position:0% + + + + align:start position:0% + +there you know it + + align:start position:0% +there you know it + + + align:start position:0% +there you know it +works and of course you what would you + + align:start position:0% +works and of course you what would you + + + align:start position:0% +works and of course you what would you +expect an evolution if that goes on too + + align:start position:0% +expect an evolution if that goes on too + + + align:start position:0% +expect an evolution if that goes on too +long you'd expect other males perhaps + + align:start position:0% +long you'd expect other males perhaps + + + align:start position:0% +long you'd expect other males perhaps +will evolve a strategy to overcome that + + align:start position:0% +will evolve a strategy to overcome that + + + align:start position:0% +will evolve a strategy to overcome that +or the female will evolve the strategy + + align:start position:0% +or the female will evolve the strategy + + + align:start position:0% +or the female will evolve the strategy +if it's to her + + align:start position:0% + + + + align:start position:0% + +benefit in dunx you have the phenomenon + + align:start position:0% +benefit in dunx you have the phenomenon + + + align:start position:0% +benefit in dunx you have the phenomenon +of last sperm + + align:start position:0% +of last sperm + + + align:start position:0% +of last sperm +precedence that means the last male that + + align:start position:0% +precedence that means the last male that + + + align:start position:0% +precedence that means the last male that +Ma with + + align:start position:0% +Ma with + + + align:start position:0% +Ma with +her it is his sperm that are the most + + align:start position:0% +her it is his sperm that are the most + + + align:start position:0% +her it is his sperm that are the most +likely to be successful ful in + + align:start position:0% +likely to be successful ful in + + + align:start position:0% +likely to be successful ful in +fertilizing her + + align:start position:0% +fertilizing her + + + align:start position:0% +fertilizing her +eggs so the males before they mate with + + align:start position:0% +eggs so the males before they mate with + + + align:start position:0% +eggs so the males before they mate with +a female will peck at her cloa region + + align:start position:0% +a female will peck at her cloa region + + + align:start position:0% +a female will peck at her cloa region +and they've observed they first didn't + + align:start position:0% +and they've observed they first didn't + + + align:start position:0% +and they've observed they first didn't +weren't sure about why he does that it + + align:start position:0% +weren't sure about why he does that it + + + align:start position:0% +weren't sure about why he does that it +seem to be part of the mating ritual but + + align:start position:0% +seem to be part of the mating ritual but + + + align:start position:0% +seem to be part of the mating ritual but +then they observe that if he does that + + align:start position:0% +then they observe that if he does that + + + align:start position:0% +then they observe that if he does that +for a while she + + align:start position:0% +for a while she + + + align:start position:0% +for a while she +excretes a fluid and if they look at + + align:start position:0% +excretes a fluid and if they look at + + + align:start position:0% +excretes a fluid and if they look at +that fluid under the microscope they + + align:start position:0% +that fluid under the microscope they + + + align:start position:0% +that fluid under the microscope they +find out there she's actually getting + + align:start position:0% +find out there she's actually getting + + + align:start position:0% +find out there she's actually getting +rid of sperm put there by an earlier + + align:start position:0% +rid of sperm put there by an earlier + + + align:start position:0% +rid of sperm put there by an earlier +male in other words that male wants to + + align:start position:0% +male in other words that male wants to + + + align:start position:0% +male in other words that male wants to +be not only the last one to make but he + + align:start position:0% +be not only the last one to make but he + + + align:start position:0% +be not only the last one to make but he +wants to reduce the chances that + + align:start position:0% +wants to reduce the chances that + + + align:start position:0% +wants to reduce the chances that +previous + + align:start position:0% +previous + + + align:start position:0% +previous +mes sperm will be able to fertilize any + + align:start position:0% +mes sperm will be able to fertilize any + + + align:start position:0% +mes sperm will be able to fertilize any +of her + + align:start position:0% +of her + + + align:start position:0% +of her +eggs the male invertebrates are even + + align:start position:0% +eggs the male invertebrates are even + + + align:start position:0% +eggs the male invertebrates are even +more interesting because they've evolved + + align:start position:0% +more interesting because they've evolved + + + align:start position:0% +more interesting because they've evolved +special methods to get rid of the sperm + + align:start position:0% +special methods to get rid of the sperm + + + align:start position:0% +special methods to get rid of the sperm +of the female some of them have penises + + align:start position:0% +of the female some of them have penises + + + align:start position:0% +of the female some of them have penises +that looks like a bottle brush they can + + align:start position:0% +that looks like a bottle brush they can + + + align:start position:0% +that looks like a bottle brush they can +put it in and scrub her out get rid of + + align:start position:0% +put it in and scrub her out get rid of + + + align:start position:0% +put it in and scrub her out get rid of +the + + align:start position:0% + + + + align:start position:0% + +spr and you can read about that on page + + align:start position:0% +spr and you can read about that on page + + + align:start position:0% +spr and you can read about that on page + + align:start position:0% + + + + align:start position:0% + +there okay now we're still not there's + + align:start position:0% +there okay now we're still not there's + + + align:start position:0% +there okay now we're still not there's +still more to this story uh in polyandry + + align:start position:0% +still more to this story uh in polyandry + + + align:start position:0% +still more to this story uh in polyandry +situations in some + + align:start position:0% +situations in some + + + align:start position:0% +situations in some +species last sperm precedence doesn't + + align:start position:0% +species last sperm precedence doesn't + + + align:start position:0% +species last sperm precedence doesn't +predict paternity the way it in the the + + align:start position:0% +predict paternity the way it in the the + + + align:start position:0% +predict paternity the way it in the the +the the + + align:start position:0% +the the + + + align:start position:0% +the the +dunck uh and if it doesn't predict + + align:start position:0% +dunck uh and if it doesn't predict + + + align:start position:0% +dunck uh and if it doesn't predict +paternity then it raises the possibility + + align:start position:0% +paternity then it raises the possibility + + + align:start position:0% +paternity then it raises the possibility +that somehow the + + align:start position:0% +that somehow the + + + align:start position:0% +that somehow the +female is able to control the + + align:start position:0% +female is able to control the + + + align:start position:0% +female is able to control the +situation maybe she can decide which + + align:start position:0% +situation maybe she can decide which + + + align:start position:0% +situation maybe she can decide which +male which sperm going to fertilize her + + align:start position:0% +male which sperm going to fertilize her + + + align:start position:0% +male which sperm going to fertilize her +Offspring so that will certainly come up + + align:start position:0% +Offspring so that will certainly come up + + + align:start position:0% +Offspring so that will certainly come up +again uh + + align:start position:0% +again uh + + + align:start position:0% +again uh +and then you have really more + + align:start position:0% +and then you have really more + + + align:start position:0% +and then you have really more +straightforward things because the more + + align:start position:0% +straightforward things because the more + + + align:start position:0% +straightforward things because the more +sperm there is the more likely it's + + align:start position:0% +sperm there is the more likely it's + + + align:start position:0% +sperm there is the more likely it's +going to be contain those the ones that + + align:start position:0% +going to be contain those the ones that + + + align:start position:0% +going to be contain those the ones that +fertilize the eggs + + align:start position:0% +fertilize the eggs + + + align:start position:0% +fertilize the eggs +so in the dragon lizard if they see + + align:start position:0% +so in the dragon lizard if they see + + + align:start position:0% +so in the dragon lizard if they see +their female with another + + align:start position:0% +their female with another + + + align:start position:0% +their female with another +male they will mate longer with her to + + align:start position:0% +male they will mate longer with her to + + + align:start position:0% +male they will mate longer with her to +increase the quantity of the ejaculate + + align:start position:0% +increase the quantity of the ejaculate + + + align:start position:0% +increase the quantity of the ejaculate +that increases the probability it's + + align:start position:0% +that increases the probability it's + + + align:start position:0% +that increases the probability it's +similar to L firm precedence okay it may + + align:start position:0% +similar to L firm precedence okay it may + + + align:start position:0% +similar to L firm precedence okay it may +be a ma major reason why less firm + + align:start position:0% +be a ma major reason why less firm + + + align:start position:0% +be a ma major reason why less firm +precedence works + + align:start position:0% +precedence works + + + align:start position:0% +precedence works +okay and there are many species that do + + align:start position:0% +okay and there are many species that do + + + align:start position:0% +okay and there are many species that do +that they simp if the the female is + + align:start position:0% +that they simp if the the female is + + + align:start position:0% +that they simp if the the female is +encountering other males a lot they'll + + align:start position:0% +encountering other males a lot they'll + + + align:start position:0% +encountering other males a lot they'll +just mate for longer periods they + + align:start position:0% +just mate for longer periods they + + + align:start position:0% +just mate for longer periods they +produce more sperm and also when they do + + align:start position:0% +produce more sperm and also when they do + + + align:start position:0% +produce more sperm and also when they do +that they occupy the female for a long + + align:start position:0% +that they occupy the female for a long + + + align:start position:0% +that they occupy the female for a long +longer period of time and the more they + + align:start position:0% +longer period of time and the more they + + + align:start position:0% +longer period of time and the more they +can occupy her the less chance she's + + align:start position:0% +can occupy her the less chance she's + + + align:start position:0% +can occupy her the less chance she's +going to get to calculate with another + + align:start position:0% +going to get to calculate with another + + + align:start position:0% +going to get to calculate with another +male and of course they can also evolve + + align:start position:0% +male and of course they can also evolve + + + align:start position:0% +male and of course they can also evolve +production of more energetic + + align:start position:0% +production of more energetic + + + align:start position:0% +production of more energetic +sperms that can beat the competition it + + align:start position:0% +sperms that can beat the competition it + + + align:start position:0% +sperms that can beat the competition it +takes a while in the reproductive tra + + align:start position:0% +takes a while in the reproductive tra + + + align:start position:0% +takes a while in the reproductive tra +for the sperm to even find the EG so + + align:start position:0% +for the sperm to even find the EG so + + + align:start position:0% +for the sperm to even find the EG so +that's another + + align:start position:0% +that's another + + + align:start position:0% +that's another +strategy and + + align:start position:0% +strategy and + + + align:start position:0% +strategy and +sociobiology science sociobiologists + + align:start position:0% +sociobiology science sociobiologists + + + align:start position:0% +sociobiology science sociobiologists +have found evidence for these various + + align:start position:0% +have found evidence for these various + + + align:start position:0% +have found evidence for these various +things as we will be discussing + + align:start position:0% +things as we will be discussing + + + align:start position:0% +things as we will be discussing +later + + align:start position:0% +later + + + align:start position:0% +later +okay I mentioned DNA analysis it's done + + align:start position:0% +okay I mentioned DNA analysis it's done + + + align:start position:0% +okay I mentioned DNA analysis it's done +on the sandpipers remember they they lay + + align:start position:0% +on the sandpipers remember they they lay + + + align:start position:0% +on the sandpipers remember they they lay +one clutch of eggs four eggs they stay + + align:start position:0% +one clutch of eggs four eggs they stay + + + align:start position:0% +one clutch of eggs four eggs they stay +for a little while and they fly off and + + align:start position:0% +for a little while and they fly off and + + + align:start position:0% +for a little while and they fly off and +they lay another clutch of eggs the + + align:start position:0% +they lay another clutch of eggs the + + + align:start position:0% +they lay another clutch of eggs the +first male has to stay with the first + + align:start position:0% +first male has to stay with the first + + + align:start position:0% +first male has to stay with the first +four so she gets another male take care + + align:start position:0% +four so she gets another male take care + + + align:start position:0% +four so she gets another male take care +of her second group what have they + + align:start position:0% +of her second group what have they + + + align:start position:0% +of her second group what have they +found the second clutch of eggs may have + + align:start position:0% +found the second clutch of eggs may have + + + align:start position:0% +found the second clutch of eggs may have +been fed by the first mate and not the + + align:start position:0% +been fed by the first mate and not the + + + align:start position:0% +been fed by the first mate and not the +second so in that case there's only one + + align:start position:0% +second so in that case there's only one + + + align:start position:0% +second so in that case there's only one +way this could happen he stored sperm + + align:start position:0% +way this could happen he stored sperm + + + align:start position:0% +way this could happen he stored sperm +from the first mate + + align:start position:0% +from the first mate + + + align:start position:0% +from the first mate +and simply delayed its use we made a we + + align:start position:0% +and simply delayed its use we made a we + + + align:start position:0% +and simply delayed its use we made a we +call it a covert choice because it's not + + align:start position:0% +call it a covert choice because it's not + + + align:start position:0% +call it a covert choice because it's not +overt + + align:start position:0% +overt + + + align:start position:0% +overt +Behavior so she's + + align:start position:0% +Behavior so she's + + + align:start position:0% +Behavior so she's +simply enslaving the second + + align:start position:0% +simply enslaving the second + + + align:start position:0% +simply enslaving the second +male you know getting him to raise her + + align:start position:0% +male you know getting him to raise her + + + align:start position:0% +male you know getting him to raise her +eggs you see she's made a choice in the + + align:start position:0% +eggs you see she's made a choice in the + + + align:start position:0% +eggs you see she's made a choice in the +quality of the genes by assessing you + + align:start position:0% +quality of the genes by assessing you + + + align:start position:0% +quality of the genes by assessing you +know the two males and so when she meets + + align:start position:0% +know the two males and so when she meets + + + align:start position:0% +know the two males and so when she meets +the second male he might be perfectly + + align:start position:0% +the second male he might be perfectly + + + align:start position:0% +the second male he might be perfectly +capable of + + align:start position:0% +capable of + + + align:start position:0% +capable of +nesting and brood pending but maybe not + + align:start position:0% +nesting and brood pending but maybe not + + + align:start position:0% +nesting and brood pending but maybe not +as attracted to her in other ways as + + align:start position:0% +as attracted to her in other ways as + + + align:start position:0% +as attracted to her in other ways as +that first male so then she'll she + + align:start position:0% +that first male so then she'll she + + + align:start position:0% +that first male so then she'll she +stored up sperm from the first male so + + align:start position:0% +stored up sperm from the first male so + + + align:start position:0% +stored up sperm from the first male so +she can make that + + align:start position:0% +she can make that + + + align:start position:0% +she can make that +choice very it's comparable to us what I + + align:start position:0% +choice very it's comparable to us what I + + + align:start position:0% +choice very it's comparable to us what I +know about + + align:start position:0% +know about + + + align:start position:0% +know about +kangaroos kangaroos will generally carry + + align:start position:0% +kangaroos kangaroos will generally carry + + + align:start position:0% +kangaroos kangaroos will generally carry +two fetuses but only one one of them + + align:start position:0% +two fetuses but only one one of them + + + align:start position:0% +two fetuses but only one one of them +will mature the other one will be held + + align:start position:0% +will mature the other one will be held + + + align:start position:0% +will mature the other one will be held +in a kind of suspended animation okay + + align:start position:0% +in a kind of suspended animation okay + + + align:start position:0% +in a kind of suspended animation okay +and then if something happens to her + + align:start position:0% +and then if something happens to her + + + align:start position:0% +and then if something happens to her +first little + + align:start position:0% +first little + + + align:start position:0% +first little +Joey he + + align:start position:0% +Joey he + + + align:start position:0% +Joey he +dies then the second one will start + + align:start position:0% +dies then the second one will start + + + align:start position:0% +dies then the second one will start +drawing in her so she's got a spare + + align:start position:0% +drawing in her so she's got a spare + + + align:start position:0% +drawing in her so she's got a spare +similar to this and it's the same father + + align:start position:0% +similar to this and it's the same father + + + align:start position:0% +similar to this and it's the same father +um but + + align:start position:0% +um but + + + align:start position:0% +um but +now at a later + + align:start position:0% +now at a later + + + align:start position:0% +now at a later +time she's got a backup fetus + + align:start position:0% +time she's got a backup fetus + + + align:start position:0% +time she's got a backup fetus +okay the last topic here the + + align:start position:0% + + + + align:start position:0% + +Leck how can a male in a Leck who never + + align:start position:0% +Leck how can a male in a Leck who never + + + align:start position:0% +Leck how can a male in a Leck who never +seems to succeed in mating with a female + + align:start position:0% +seems to succeed in mating with a female + + + align:start position:0% +seems to succeed in mating with a female +never nevertheless + + align:start position:0% +never nevertheless + + + align:start position:0% +never nevertheless +benefit by participating in that like + + align:start position:0% +benefit by participating in that like + + + align:start position:0% +benefit by participating in that like +why does he + + align:start position:0% +why does he + + + align:start position:0% +why does he +participate he's obviously not the Hot + + align:start position:0% +participate he's obviously not the Hot + + + align:start position:0% +participate he's obviously not the Hot +Shot okay well there's various models to + + align:start position:0% +Shot okay well there's various models to + + + align:start position:0% +Shot okay well there's various models to +deal with that whole issue of the leg + + align:start position:0% +deal with that whole issue of the leg + + + align:start position:0% +deal with that whole issue of the leg +hot the hot spot model this is the + + align:start position:0% +hot the hot spot model this is the + + + align:start position:0% +hot the hot spot model this is the +advantage that let's say the females are + + align:start position:0% +advantage that let's say the females are + + + align:start position:0% +advantage that let's say the females are +not going to mate for very long then + + align:start position:0% +not going to mate for very long then + + + align:start position:0% +not going to mate for very long then +you've got a position yourself where all + + align:start position:0% +you've got a position yourself where all + + + align:start position:0% +you've got a position yourself where all +the females aren coming so they go to a + + align:start position:0% +the females aren coming so they go to a + + + align:start position:0% +the females aren coming so they go to a +place where all the females come that's + + align:start position:0% +place where all the females come that's + + + align:start position:0% +place where all the females come that's +called The Hot Spot model Hot Spot model + + align:start position:0% +called The Hot Spot model Hot Spot model + + + align:start position:0% +called The Hot Spot model Hot Spot model +well you can benefit by being near a hot + + align:start position:0% +well you can benefit by being near a hot + + + align:start position:0% +well you can benefit by being near a hot +shot because he will attract the females + + align:start position:0% +shot because he will attract the females + + + align:start position:0% +shot because he will attract the females +and maybe you'll get it to + + align:start position:0% +and maybe you'll get it to + + + align:start position:0% +and maybe you'll get it to +him there's some evidence for + + align:start position:0% +him there's some evidence for + + + align:start position:0% +him there's some evidence for +that another the female preference model + + align:start position:0% +that another the female preference model + + + align:start position:0% +that another the female preference model +is simply that females because of their + + align:start position:0% +is simply that females because of their + + + align:start position:0% +is simply that females because of their +they're facing predators and Lex groups + + align:start position:0% +they're facing predators and Lex groups + + + align:start position:0% +they're facing predators and Lex groups +of animals making mate choices are going + + align:start position:0% +of animals making mate choices are going + + + align:start position:0% +of animals making mate choices are going +to attract Predators too so he wants + + align:start position:0% +to attract Predators too so he wants + + + align:start position:0% +to attract Predators too so he wants +this to be over with very quickly so + + align:start position:0% +this to be over with very quickly so + + + align:start position:0% +this to be over with very quickly so +this maybe Lex have evolved in those + + align:start position:0% +this maybe Lex have evolved in those + + + align:start position:0% +this maybe Lex have evolved in those +species just to speed it up get the + + align:start position:0% +species just to speed it up get the + + + align:start position:0% +species just to speed it up get the +whole thing done in very brief period of + + align:start position:0% +whole thing done in very brief period of + + + align:start position:0% +whole thing done in very brief period of +time the model that is preferred by + + align:start position:0% +time the model that is preferred by + + + align:start position:0% +time the model that is preferred by +Scott and it doesn't mean these other + + align:start position:0% +Scott and it doesn't mean these other + + + align:start position:0% +Scott and it doesn't mean these other +things aren't factors in the evolution + + align:start position:0% +things aren't factors in the evolution + + + align:start position:0% +things aren't factors in the evolution +the and since it occurs in over 200 + + align:start position:0% +the and since it occurs in over 200 + + + align:start position:0% +the and since it occurs in over 200 +species it's likely that more than one + + align:start position:0% +species it's likely that more than one + + + align:start position:0% +species it's likely that more than one +factor has influenced its Evolution but + + align:start position:0% +factor has influenced its Evolution but + + + align:start position:0% +factor has influenced its Evolution but +K selection simply means that in many + + align:start position:0% +K selection simply means that in many + + + align:start position:0% +K selection simply means that in many +lexs most of those males are related to + + align:start position:0% +lexs most of those males are related to + + + align:start position:0% +lexs most of those males are related to +each other so even if some of many those + + align:start position:0% +each other so even if some of many those + + + align:start position:0% +each other so even if some of many those +males don't get a chance to M at all + + align:start position:0% +males don't get a chance to M at all + + + align:start position:0% +males don't get a chance to M at all +maybe they're still benefiting because + + align:start position:0% +maybe they're still benefiting because + + + align:start position:0% +maybe they're still benefiting because +they sell jeans with that hot shot + + align:start position:0% +they sell jeans with that hot shot + + + align:start position:0% +they sell jeans with that hot shot +okay big brother can + + align:start position:0% +okay big brother can + + + align:start position:0% +okay big brother can +make but he carries a lot of same de + + align:start position:0% +make but he carries a lot of same de + + + align:start position:0% +make but he carries a lot of same de +diety okay so you see it because when + + align:start position:0% +diety okay so you see it because when + + + align:start position:0% +diety okay so you see it because when +you look + + align:start position:0% +you look + + + align:start position:0% +you look +at genetic fitness you have to + + align:start position:0% +at genetic fitness you have to + + + align:start position:0% +at genetic fitness you have to +consider how many copies of your genes + + align:start position:0% +consider how many copies of your genes + + + align:start position:0% +consider how many copies of your genes +are getting passed + + align:start position:0% +are getting passed + + + align:start position:0% +are getting passed +on and you are you increase your Fitness + + align:start position:0% +on and you are you increase your Fitness + + + align:start position:0% +on and you are you increase your Fitness +by helping your + + align:start position:0% +by helping your + + + align:start position:0% +by helping your +brother so the females are more + + align:start position:0% +brother so the females are more + + + align:start position:0% +brother so the females are more +attracted to the Le okay only your + + align:start position:0% +attracted to the Le okay only your + + + align:start position:0% +attracted to the Le okay only your +brother gets to mate but you're still + + align:start position:0% +brother gets to mate but you're still + + + align:start position:0% +brother gets to mate but you're still +getting passing on jeans okay that's the + + align:start position:0% +getting passing on jeans okay that's the + + + align:start position:0% +getting passing on jeans okay that's the +kin selection + + align:start position:0% +kin selection + + + align:start position:0% +kin selection +model and I'm just pointing out they're + + align:start position:0% +model and I'm just pointing out they're + + + align:start position:0% +model and I'm just pointing out they're +not mutually exclusive these + + align:start position:0% +not mutually exclusive these + + + align:start position:0% +not mutually exclusive these +models and yet we know there should be + + align:start position:0% +models and yet we know there should be + + + align:start position:0% +models and yet we know there should be +it seems like it's a setup for reducing + + align:start position:0% +it seems like it's a setup for reducing + + + align:start position:0% +it seems like it's a setup for reducing +genetic variation and yet the genetic + + align:start position:0% +genetic variation and yet the genetic + + + align:start position:0% +genetic variation and yet the genetic +studies indicate that somehow the + + align:start position:0% +studies indicate that somehow the + + + align:start position:0% +studies indicate that somehow the +females do manage to preserve a lot of + + align:start position:0% +females do manage to preserve a lot of + + + align:start position:0% +females do manage to preserve a lot of +variability indicating that even though + + align:start position:0% +variability indicating that even though + + + align:start position:0% +variability indicating that even though +the Behavioral Studies by scientists + + align:start position:0% +the Behavioral Studies by scientists + + + align:start position:0% +the Behavioral Studies by scientists +haven't seen many of those other males + + align:start position:0% +haven't seen many of those other males + + + align:start position:0% +haven't seen many of those other males +mating uh it's clear that a lot of them + + align:start position:0% +mating uh it's clear that a lot of them + + + align:start position:0% +mating uh it's clear that a lot of them +do so my guess is that the females are + + align:start position:0% +do so my guess is that the females are + + + align:start position:0% +do so my guess is that the females are +in fact in addition to mating with that + + align:start position:0% +in fact in addition to mating with that + + + align:start position:0% +in fact in addition to mating with that +the Hot Shot male they're probably + + align:start position:0% +the Hot Shot male they're probably + + + align:start position:0% +the Hot Shot male they're probably +mating additional times with the males + + align:start position:0% +mating additional times with the males + + + align:start position:0% +mating additional times with the males +before they they + + align:start position:0% +before they they + + + align:start position:0% +before they they +leave okay but this is unclear from the + + align:start position:0% +leave okay but this is unclear from the + + + align:start position:0% +leave okay but this is unclear from the +studies all + + align:start position:0% +studies all + + + align:start position:0% +studies all +right sorry I went over little bit \ No newline at end of file diff --git a/Av9sFr_NsBU.txt b/Av9sFr_NsBU.txt new file mode 100644 index 0000000000000000000000000000000000000000..1f299acc29160377500875fc52ee345be3dc6cdf --- /dev/null +++ b/Av9sFr_NsBU.txt @@ -0,0 +1,8875 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit MIT opencourseware + + align:start position:0% +of MIT courses visit MIT opencourseware + + + align:start position:0% +of MIT courses visit MIT opencourseware +at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu okay um most everyone's here + + align:start position:0% +ocw.mit.edu okay um most everyone's here + + + align:start position:0% +ocw.mit.edu okay um most everyone's here +um we're still going to take a few + + align:start position:0% +um we're still going to take a few + + + align:start position:0% +um we're still going to take a few +minutes to wait for the last um few + + align:start position:0% +minutes to wait for the last um few + + + align:start position:0% +minutes to wait for the last um few +people to show up um I don't have a ton + + align:start position:0% +people to show up um I don't have a ton + + + align:start position:0% +people to show up um I don't have a ton +of announcements + + align:start position:0% +of announcements + + + align:start position:0% +of announcements +but if you looked at the syllabus you + + align:start position:0% +but if you looked at the syllabus you + + + align:start position:0% +but if you looked at the syllabus you +might notice that there are a couple + + align:start position:0% +might notice that there are a couple + + + align:start position:0% +might notice that there are a couple +days where we have I think we've got TBD + + align:start position:0% +days where we have I think we've got TBD + + + align:start position:0% +days where we have I think we've got TBD +as the topic like to be determined um + + align:start position:0% +as the topic like to be determined um + + + align:start position:0% +as the topic like to be determined um +what I'd like to do is just take a quick + + align:start position:0% +what I'd like to do is just take a quick + + + align:start position:0% +what I'd like to do is just take a quick +poll um from you all is there anything + + align:start position:0% +poll um from you all is there anything + + + align:start position:0% +poll um from you all is there anything +that you are interested in learning + + align:start position:0% +that you are interested in learning + + + align:start position:0% +that you are interested in learning +about in the creation of video games + + align:start position:0% +about in the creation of video games + + + align:start position:0% +about in the creation of video games +that you either we haven't talked about + + align:start position:0% +that you either we haven't talked about + + + align:start position:0% +that you either we haven't talked about +it in class yet maybe we've talked about + + align:start position:0% +it in class yet maybe we've talked about + + + align:start position:0% +it in class yet maybe we've talked about +it but not fully um you've looked at the + + align:start position:0% +it but not fully um you've looked at the + + + align:start position:0% +it but not fully um you've looked at the +syllabus and it and it's not there on + + align:start position:0% +syllabus and it and it's not there on + + + align:start position:0% +syllabus and it and it's not there on +the syllabus um so any spe and it and or + + align:start position:0% +the syllabus um so any spe and it and or + + + align:start position:0% +the syllabus um so any spe and it and or +it's something that you think is going + + align:start position:0% +it's something that you think is going + + + align:start position:0% +it's something that you think is going +to be directly useful for the games that + + align:start position:0% +to be directly useful for the games that + + + align:start position:0% +to be directly useful for the games that +you're working on right + + align:start position:0% +you're working on right + + + align:start position:0% +you're working on right +now so just putting that out there if + + align:start position:0% +now so just putting that out there if + + + align:start position:0% +now so just putting that out there if +there any topics you might want to talk + + align:start position:0% +there any topics you might want to talk + + + align:start position:0% +there any topics you might want to talk +about learn + + align:start position:0% +about learn + + + align:start position:0% +about learn +about let me + + align:start position:0% +about let me + + + align:start position:0% +about let me +know + + align:start position:0% +know + + + align:start position:0% +know +yes other classes us like the last last + + align:start position:0% +yes other classes us like the last last + + + align:start position:0% +yes other classes us like the last last +class of the last two classes us like + + align:start position:0% +class of the last two classes us like + + + align:start position:0% +class of the last two classes us like +what people actually do in Industry okay + + align:start position:0% +what people actually do in Industry okay + + + align:start position:0% +what people actually do in Industry okay +so yeah cool so what people do in the + + align:start position:0% +so yeah cool so what people do in the + + + align:start position:0% +so yeah cool so what people do in the +industry + + align:start position:0% + + + + align:start position:0% + +cool you are in luck on + + align:start position:0% +cool you are in luck on + + + align:start position:0% +cool you are in luck on +December 1st and 3D on the 1 we're + + align:start position:0% +December 1st and 3D on the 1 we're + + + align:start position:0% +December 1st and 3D on the 1 we're +having a business and games um panel so + + align:start position:0% +having a business and games um panel so + + + align:start position:0% +having a business and games um panel so +two um two independent developers in the + + align:start position:0% +two um two independent developers in the + + + align:start position:0% +two um two independent developers in the +area are going to come by and talk about + + align:start position:0% +area are going to come by and talk about + + + align:start position:0% +area are going to come by and talk about +um how they started their companies what + + align:start position:0% +um how they started their companies what + + + align:start position:0% +um how they started their companies what +do they do what's their daily life + + align:start position:0% +do they do what's their daily life + + + align:start position:0% +do they do what's their daily life +things like that and then another one + + align:start position:0% +things like that and then another one + + + align:start position:0% +things like that and then another one +following that is um the community + + align:start position:0% +following that is um the community + + + align:start position:0% +following that is um the community +manager for fire hose games um Sean + + align:start position:0% +manager for fire hose games um Sean + + + align:start position:0% +manager for fire hose games um Sean +Baptist is going to talk to us about how + + align:start position:0% +Baptist is going to talk to us about how + + + align:start position:0% +Baptist is going to talk to us about how +does he get how do they get their games + + align:start position:0% +does he get how do they get their games + + + align:start position:0% +does he get how do they get their games +out in the world and how do they get + + align:start position:0% +out in the world and how do they get + + + align:start position:0% +out in the world and how do they get +people to play their games um and how do + + align:start position:0% +people to play their games um and how do + + + align:start position:0% +people to play their games um and how do +they engage their their their fan base + + align:start position:0% +they engage their their their fan base + + + align:start position:0% +they engage their their their fan base +and how do they even just create a fan + + align:start position:0% +and how do they even just create a fan + + + align:start position:0% +and how do they even just create a fan +base in general um so that's not on the + + align:start position:0% +base in general um so that's not on the + + + align:start position:0% +base in general um so that's not on the +syllabus but that will be we will be + + align:start position:0% +syllabus but that will be we will be + + + align:start position:0% +syllabus but that will be we will be +doing + + align:start position:0% +doing + + + align:start position:0% +doing +that any other + + align:start position:0% + + + + align:start position:0% + +topics okay I want to ask this again in + + align:start position:0% +topics okay I want to ask this again in + + + align:start position:0% +topics okay I want to ask this again in +a couple weeks um in case something pops + + align:start position:0% +a couple weeks um in case something pops + + + align:start position:0% +a couple weeks um in case something pops +up because you probably haven't done a + + align:start position:0% +up because you probably haven't done a + + + align:start position:0% +up because you probably haven't done a +lot of technical things with your um + + align:start position:0% +lot of technical things with your um + + + align:start position:0% +lot of technical things with your um +with your game engine yet um so if + + align:start position:0% +with your game engine yet um so if + + + align:start position:0% +with your game engine yet um so if +there's anything gaming specific that + + align:start position:0% +there's anything gaming specific that + + + align:start position:0% +there's anything gaming specific that +you might want to know about um either + + align:start position:0% +you might want to know about um either + + + align:start position:0% +you might want to know about um either +let us know through the mail through the + + align:start position:0% +let us know through the mail through the + + + align:start position:0% +let us know through the mail through the +video game boss's um email address or + + align:start position:0% +video game boss's um email address or + + + align:start position:0% +video game boss's um email address or +let us know a class yeah who would be + + align:start position:0% +let us know a class yeah who would be + + + align:start position:0% +let us know a class yeah who would be +giving these lectures like is this open + + align:start position:0% +giving these lectures like is this open + + + align:start position:0% +giving these lectures like is this open +to can you get I can get people so I can + + align:start position:0% +to can you get I can get people so I can + + + align:start position:0% +to can you get I can get people so I can +I can get people who are um local um + + align:start position:0% +I can get people who are um local um + + + align:start position:0% +I can get people who are um local um +we've got connections to local industry + + align:start position:0% +we've got connections to local industry + + + align:start position:0% +we've got connections to local industry +um we've got connections to the people + + align:start position:0% +um we've got connections to the people + + + align:start position:0% +um we've got connections to the people +who make the tools in some cases + + align:start position:0% +who make the tools in some cases + + + align:start position:0% +who make the tools in some cases +depending on the tool that's kind of why + + align:start position:0% +depending on the tool that's kind of why + + + align:start position:0% +depending on the tool that's kind of why +I'm asking now because it gives me time + + align:start position:0% +I'm asking now because it gives me time + + + align:start position:0% +I'm asking now because it gives me time +to to to find new to to fill new gaps uh + + align:start position:0% +to to to find new to to fill new gaps uh + + + align:start position:0% +to to to find new to to fill new gaps uh +also so it might be something that we + + align:start position:0% +also so it might be something that we + + + align:start position:0% +also so it might be something that we +can talk to um so if there's anything + + align:start position:0% +can talk to um so if there's anything + + + align:start position:0% +can talk to um so if there's anything +design related that you think is useful + + align:start position:0% +design related that you think is useful + + + align:start position:0% +design related that you think is useful +for your for your games that we haven't + + align:start position:0% +for your for your games that we haven't + + + align:start position:0% +for your for your games that we haven't +talked about yet um and you don't see it + + align:start position:0% +talked about yet um and you don't see it + + + align:start position:0% +talked about yet um and you don't see it +on the schedule let us know um if + + align:start position:0% +on the schedule let us know um if + + + align:start position:0% +on the schedule let us know um if +there's anything technical related um + + align:start position:0% +there's anything technical related um + + + align:start position:0% +there's anything technical related um +Drew can can can come up and and say + + align:start position:0% +Drew can can can come up and and say + + + align:start position:0% +Drew can can can come up and and say +something the other thing we can do is + + align:start position:0% +something the other thing we can do is + + + align:start position:0% +something the other thing we can do is +if there's anything that you want to do + + align:start position:0% +if there's anything that you want to do + + + align:start position:0% +if there's anything that you want to do +or if you want to set up office hours in + + align:start position:0% +or if you want to set up office hours in + + + align:start position:0% +or if you want to set up office hours in +class um to talk about a certain topic + + align:start position:0% +class um to talk about a certain topic + + + align:start position:0% +class um to talk about a certain topic +for your for your um for your games + + align:start position:0% +for your for your um for your games + + + align:start position:0% +for your for your um for your games +specifically technical issues technical + + align:start position:0% +specifically technical issues technical + + + align:start position:0% +specifically technical issues technical +questions um that's what Drew is here + + align:start position:0% +questions um that's what Drew is here + + + align:start position:0% +questions um that's what Drew is here +for to to come and talk to you to talk + + align:start position:0% +for to to come and talk to you to talk + + + align:start position:0% +for to to come and talk to you to talk +with your group as a whole or just + + align:start position:0% +with your group as a whole or just + + + align:start position:0% +with your group as a whole or just +individual members of your group to talk + + align:start position:0% +individual members of your group to talk + + + align:start position:0% +individual members of your group to talk +about the issues that you have so we can + + align:start position:0% +about the issues that you have so we can + + + align:start position:0% +about the issues that you have so we can +do that during class during our + + align:start position:0% +do that during class during our + + + align:start position:0% +do that during class during our +scheduled one and a half to two hour um + + align:start position:0% +scheduled one and a half to two hour um + + + align:start position:0% +scheduled one and a half to two hour um +working class periods or um you can set + + align:start position:0% +working class periods or um you can set + + + align:start position:0% +working class periods or um you can set +up work office hours with + + align:start position:0% + + + + align:start position:0% + +him okay um just give people a couple + + align:start position:0% +him okay um just give people a couple + + + align:start position:0% +him okay um just give people a couple +more minutes the attendance sheet is + + align:start position:0% +more minutes the attendance sheet is + + + align:start position:0% +more minutes the attendance sheet is +moving around um + + align:start position:0% +moving around um + + + align:start position:0% +moving around um +so is everybody sitting with their teams + + align:start position:0% +so is everybody sitting with their teams + + + align:start position:0% +so is everybody sitting with their teams +right now does it look like + + align:start position:0% +right now does it look like + + + align:start position:0% +right now does it look like +can we just show I'm going to go across + + align:start position:0% +can we just show I'm going to go across + + + align:start position:0% +can we just show I'm going to go across +and just kind of try to figure out which + + align:start position:0% +and just kind of try to figure out which + + + align:start position:0% +and just kind of try to figure out which +of these teams are so this is the snap + + align:start position:0% +of these teams are so this is the snap + + + align:start position:0% +of these teams are so this is the snap +team is everyone + + align:start position:0% +team is everyone + + + align:start position:0% +team is everyone +here two okay uh which team this is + + align:start position:0% +here two okay uh which team this is + + + align:start position:0% +here two okay uh which team this is +forecast based Futures over here right + + align:start position:0% +forecast based Futures over here right + + + align:start position:0% +forecast based Futures over here right +how far do you go John are you in this + + align:start position:0% +how far do you go John are you in this + + + align:start position:0% +how far do you go John are you in this +team or you in the next team cool all + + align:start position:0% +team or you in the next team cool all + + + align:start position:0% +team or you in the next team cool all +right next team over which team are you + + align:start position:0% +right next team over which team are you + + + align:start position:0% +right next team over which team are you +Kera + + align:start position:0% +Kera + + + align:start position:0% +Kera +no you're a Col team were you the um + + align:start position:0% +no you're a Col team were you the um + + + align:start position:0% +no you're a Col team were you the um +island group Animal Crossing one cool um + + align:start position:0% +island group Animal Crossing one cool um + + + align:start position:0% +island group Animal Crossing one cool um +and then in the front here we've got + + align:start position:0% +and then in the front here we've got + + + align:start position:0% +and then in the front here we've got +Heatwave and in the back it's the other + + align:start position:0% +Heatwave and in the back it's the other + + + align:start position:0% +Heatwave and in the back it's the other +call group okay um I did not get a + + align:start position:0% +call group okay um I did not get a + + + align:start position:0% +call group okay um I did not get a +chance to play your game so but I will + + align:start position:0% +chance to play your game so but I will + + + align:start position:0% +chance to play your game so but I will +eventually um cool so there's G to be a + + align:start position:0% +eventually um cool so there's G to be a + + + align:start position:0% +eventually um cool so there's G to be a +little bit of interactivity in the talk + + align:start position:0% +little bit of interactivity in the talk + + + align:start position:0% +little bit of interactivity in the talk +um I've given this talk before um I + + align:start position:0% +um I've given this talk before um I + + + align:start position:0% +um I've given this talk before um I +rewrote the lectures and I haven't given + + align:start position:0% +rewrote the lectures and I haven't given + + + align:start position:0% +rewrote the lectures and I haven't given +it since I rewrote the lecture so we'll + + align:start position:0% +it since I rewrote the lecture so we'll + + + align:start position:0% +it since I rewrote the lecture so we'll +see how it goes they're my backup to let + + align:start position:0% +see how it goes they're my backup to let + + + align:start position:0% +see how it goes they're my backup to let +me know if I forgot + + align:start position:0% +me know if I forgot + + + align:start position:0% +me know if I forgot +anything um there will be some reading + + align:start position:0% +anything um there will be some reading + + + align:start position:0% +anything um there will be some reading +on this that I'm going to put into + + align:start position:0% +on this that I'm going to put into + + + align:start position:0% +on this that I'm going to put into +Stellar so if you are um interested in + + align:start position:0% +Stellar so if you are um interested in + + + align:start position:0% +Stellar so if you are um interested in +the topic if you're if you have more the + + align:start position:0% +the topic if you're if you have more the + + + align:start position:0% +the topic if you're if you have more the +topic and you want to read the reading I + + align:start position:0% +topic and you want to read the reading I + + + align:start position:0% +topic and you want to read the reading I +highly recommend it especially if you + + align:start position:0% +highly recommend it especially if you + + + align:start position:0% +highly recommend it especially if you +think you're going to be in a leadership + + align:start position:0% +think you're going to be in a leadership + + + align:start position:0% +think you're going to be in a leadership +position in the future or any kind of + + align:start position:0% +position in the future or any kind of + + + align:start position:0% +position in the future or any kind of +managerial position or you're interested + + align:start position:0% +managerial position or you're interested + + + align:start position:0% +managerial position or you're interested +in just psychology and how people talk + + align:start position:0% +in just psychology and how people talk + + + align:start position:0% +in just psychology and how people talk +to each other and work together um so + + align:start position:0% +to each other and work together um so + + + align:start position:0% +to each other and work together um so +our three main topics um this will + + align:start position:0% +our three main topics um this will + + + align:start position:0% +our three main topics um this will +actually be pretty quick on this lecture + + align:start position:0% +actually be pretty quick on this lecture + + + align:start position:0% +actually be pretty quick on this lecture +um we're going to talk about we're going + + align:start position:0% +um we're going to talk about we're going + + + align:start position:0% +um we're going to talk about we're going +to do a really quick review of agile um + + align:start position:0% +to do a really quick review of agile um + + + align:start position:0% +to do a really quick review of agile um +we're going to talk about Team Dynamics + + align:start position:0% +we're going to talk about Team Dynamics + + + align:start position:0% +we're going to talk about Team Dynamics +and then we're going to talk about how + + align:start position:0% +and then we're going to talk about how + + + align:start position:0% +and then we're going to talk about how +do distributed agile teams perform so + + align:start position:0% +do distributed agile teams perform so + + + align:start position:0% +do distributed agile teams perform so +what are some of the the best practices + + align:start position:0% +what are some of the the best practices + + + align:start position:0% +what are some of the the best practices +they have uh for performing and then + + align:start position:0% +they have uh for performing and then + + + align:start position:0% +they have uh for performing and then +you're going to work in class um you'll + + align:start position:0% +you're going to work in class um you'll + + + align:start position:0% +you're going to work in class um you'll +have at least two hours to work in class + + align:start position:0% +have at least two hours to work in class + + + align:start position:0% +have at least two hours to work in class +today if not a little bit more than + + align:start position:0% +today if not a little bit more than + + + align:start position:0% +today if not a little bit more than +that so agile processes if you forget + + align:start position:0% +that so agile processes if you forget + + + align:start position:0% +that so agile processes if you forget +everything in this class you end the + + align:start position:0% +everything in this class you end the + + + align:start position:0% +everything in this class you end the +class you go into the into the real + + align:start position:0% +class you go into the into the real + + + align:start position:0% +class you go into the into the real +world you and somebody asks you what is + + align:start position:0% +world you and somebody asks you what is + + + align:start position:0% +world you and somebody asks you what is +agile um I hope you remember this part + + align:start position:0% +agile um I hope you remember this part + + + align:start position:0% +agile um I hope you remember this part +um iterative development is anybody + + align:start position:0% +um iterative development is anybody + + + align:start position:0% +um iterative development is anybody +doing does anybody consider what they're + + align:start position:0% +doing does anybody consider what they're + + + align:start position:0% +doing does anybody consider what they're +doing iterated development on their + + align:start position:0% +doing iterated development on their + + + align:start position:0% +doing iterated development on their +projects right + + align:start position:0% +projects right + + + align:start position:0% +projects right +now are you working in short periods of + + align:start position:0% +now are you working in short periods of + + + align:start position:0% +now are you working in short periods of +time so you've broken up your time into + + align:start position:0% +time so you've broken up your time into + + + align:start position:0% +time so you've broken up your time into +small Sprints are you doing all you + + align:start position:0% +small Sprints are you doing all you + + + align:start position:0% +small Sprints are you doing all you +can't really read it that well in the + + align:start position:0% +can't really read it that well in the + + + align:start position:0% +can't really read it that well in the +slide um but are you within that short + + align:start position:0% +slide um but are you within that short + + + align:start position:0% +slide um but are you within that short +period of time designing what you're + + align:start position:0% +period of time designing what you're + + + align:start position:0% +period of time designing what you're +going to work on planning how how it's + + align:start position:0% +going to work on planning how how it's + + + align:start position:0% +going to work on planning how how it's +going to work doing it and then testing + + align:start position:0% +going to work doing it and then testing + + + align:start position:0% +going to work doing it and then testing +it evaluating the test and changing are + + align:start position:0% +it evaluating the test and changing are + + + align:start position:0% +it evaluating the test and changing are +you doing all of that within one week or + + align:start position:0% +you doing all of that within one week or + + + align:start position:0% +you doing all of that within one week or +or two week + + align:start position:0% +or two week + + + align:start position:0% +or two week +cycle raise your hands yay raise your + + align:start position:0% +cycle raise your hands yay raise your + + + align:start position:0% +cycle raise your hands yay raise your +hand so yes raise your + + align:start position:0% +hand so yes raise your + + + align:start position:0% +hand so yes raise your +hands no raise your hands it's okay if + + align:start position:0% +hands no raise your hands it's okay if + + + align:start position:0% +hands no raise your hands it's okay if +you say + + align:start position:0% +you say + + + align:start position:0% +you say +now okay um if you if you're doing + + align:start position:0% +now okay um if you if you're doing + + + align:start position:0% +now okay um if you if you're doing +something that looks like this then + + align:start position:0% +something that looks like this then + + + align:start position:0% +something that looks like this then +great + + align:start position:0% +great + + + align:start position:0% +great +um and as as remember um agile in + + align:start position:0% +um and as as remember um agile in + + + align:start position:0% +um and as as remember um agile in +particular scrum processes um they're + + align:start position:0% +particular scrum processes um they're + + + align:start position:0% +particular scrum processes um they're +based on these three pillars that um + + align:start position:0% +based on these three pillars that um + + + align:start position:0% +based on these three pillars that um +that Sarah talked about when we first + + align:start position:0% +that Sarah talked about when we first + + + align:start position:0% +that Sarah talked about when we first +brought this up um so the pillar of + + align:start position:0% +brought this up um so the pillar of + + + align:start position:0% +brought this up um so the pillar of +transparency um and what we mean by + + align:start position:0% +transparency um and what we mean by + + + align:start position:0% +transparency um and what we mean by +transparency there we really just mean a + + align:start position:0% +transparency there we really just mean a + + + align:start position:0% +transparency there we really just mean a +common nomenclature I to be honest I + + align:start position:0% +common nomenclature I to be honest I + + + align:start position:0% +common nomenclature I to be honest I +don't care what you call the things that + + align:start position:0% +don't care what you call the things that + + + align:start position:0% +don't care what you call the things that +you that you that you use as part of + + align:start position:0% +you that you that you use as part of + + + align:start position:0% +you that you that you use as part of +your process in your in your team so + + align:start position:0% +your process in your in your team so + + + align:start position:0% +your process in your in your team so +long as everyone within the team knows + + align:start position:0% +long as everyone within the team knows + + + align:start position:0% +long as everyone within the team knows +what it is so so long as whoever you're + + align:start position:0% +what it is so so long as whoever you're + + + align:start position:0% +what it is so so long as whoever you're +submitting those those um processes to + + align:start position:0% +submitting those those um processes to + + + align:start position:0% +submitting those those um processes to +also know it know who it is so we're not + + align:start position:0% +also know it know who it is so we're not + + + align:start position:0% +also know it know who it is so we're not +acting as your product owners in the + + align:start position:0% +acting as your product owners in the + + + align:start position:0% +acting as your product owners in the +class but if you had a product owner + + align:start position:0% +class but if you had a product owner + + + align:start position:0% +class but if you had a product owner +they should also know what you're + + align:start position:0% +they should also know what you're + + + align:start position:0% +they should also know what you're +calling things what you're calling your + + align:start position:0% +calling things what you're calling your + + + align:start position:0% +calling things what you're calling your +product backlog what you're calling a + + align:start position:0% +product backlog what you're calling a + + + align:start position:0% +product backlog what you're calling a +task um how you're estimating and how + + align:start position:0% +task um how you're estimating and how + + + align:start position:0% +task um how you're estimating and how +you're doing your processes so everyone + + align:start position:0% +you're doing your processes so everyone + + + align:start position:0% +you're doing your processes so everyone +on the team should know it not just in a + + align:start position:0% +on the team should know it not just in a + + + align:start position:0% +on the team should know it not just in a +more traditional manner a project + + align:start position:0% +more traditional manner a project + + + align:start position:0% +more traditional manner a project +manager knowing what what all the + + align:start position:0% +manager knowing what what all the + + + align:start position:0% +manager knowing what what all the +processes are uh there's a number of + + align:start position:0% +processes are uh there's a number of + + + align:start position:0% +processes are uh there's a number of +inspection that's going on on so um + + align:start position:0% +inspection that's going on on so um + + + align:start position:0% +inspection that's going on on so um +through the process you are taking a + + align:start position:0% +through the process you are taking a + + + align:start position:0% +through the process you are taking a +look at all the artifacts that you + + align:start position:0% +look at all the artifacts that you + + + align:start position:0% +look at all the artifacts that you +created so those backlog items um task + + align:start position:0% +created so those backlog items um task + + + align:start position:0% +created so those backlog items um task +lists things like that that you're + + align:start position:0% +lists things like that that you're + + + align:start position:0% +lists things like that that you're +creating during the process um you're + + align:start position:0% +creating during the process um you're + + + align:start position:0% +creating during the process um you're +inspecting it in particular you're + + align:start position:0% +inspecting it in particular you're + + + align:start position:0% +inspecting it in particular you're +inspecting it during meetings so you're + + align:start position:0% +inspecting it during meetings so you're + + + align:start position:0% +inspecting it during meetings so you're +taking a look at what you've done in a + + align:start position:0% +taking a look at what you've done in a + + + align:start position:0% +taking a look at what you've done in a +meeting and talking about it so you're + + align:start position:0% +meeting and talking about it so you're + + + align:start position:0% +meeting and talking about it so you're +not just doing a process you're doing a + + align:start position:0% +not just doing a process you're doing a + + + align:start position:0% +not just doing a process you're doing a +process and you're talking about it and + + align:start position:0% +process and you're talking about it and + + + align:start position:0% +process and you're talking about it and +you're actively thinking about the + + align:start position:0% +you're actively thinking about the + + + align:start position:0% +you're actively thinking about the +process and then you're adapting So + + align:start position:0% +process and then you're adapting So + + + align:start position:0% +process and then you're adapting So +based on evidence um based on um need + + align:start position:0% +based on evidence um based on um need + + + align:start position:0% +based on evidence um based on um need +changes in needs you are changing that + + align:start position:0% +changes in needs you are changing that + + + align:start position:0% +changes in needs you are changing that +process again if you're doing any one of + + align:start position:0% +process again if you're doing any one of + + + align:start position:0% +process again if you're doing any one of +these three things you're doing process + + align:start position:0% +these three things you're doing process + + + align:start position:0% +these three things you're doing process +as well and you're doing agile you're + + align:start position:0% +as well and you're doing agile you're + + + align:start position:0% +as well and you're doing agile you're +you're doing some form of agile like + + align:start position:0% +you're doing some form of agile like + + + align:start position:0% +you're doing some form of agile like +process that's another thing I hope you + + align:start position:0% +process that's another thing I hope you + + + align:start position:0% +process that's another thing I hope you +hope you take from the + + align:start position:0% +hope you take from the + + + align:start position:0% +hope you take from the +class um the agile Manifesto and it's + + align:start position:0% +class um the agile Manifesto and it's + + + align:start position:0% +class um the agile Manifesto and it's +kind of a it is a Manifesto it is an + + align:start position:0% +kind of a it is a Manifesto it is an + + + align:start position:0% +kind of a it is a Manifesto it is an +idea it is a um it is something that has + + align:start position:0% +idea it is a um it is something that has + + + align:start position:0% +idea it is a um it is something that has +some political weight behind it is + + align:start position:0% +some political weight behind it is + + + align:start position:0% +some political weight behind it is +saying this is the way to do things this + + align:start position:0% +saying this is the way to do things this + + + align:start position:0% +saying this is the way to do things this +is the right way to do things um but + + align:start position:0% +is the right way to do things um but + + + align:start position:0% +is the right way to do things um but +it's actually more vague than that it's + + align:start position:0% +it's actually more vague than that it's + + + align:start position:0% +it's actually more vague than that it's +really just saying + + align:start position:0% +really just saying + + + align:start position:0% +really just saying +here are some four key things that we + + align:start position:0% +here are some four key things that we + + + align:start position:0% +here are some four key things that we +feel are more important than other four + + align:start position:0% +feel are more important than other four + + + align:start position:0% +feel are more important than other four +key things um and today we're going to + + align:start position:0% +key things um and today we're going to + + + align:start position:0% +key things um and today we're going to +focus so the first the first item is + + align:start position:0% +focus so the first the first item is + + + align:start position:0% +focus so the first the first item is +individuals and interactions over + + align:start position:0% +individuals and interactions over + + + align:start position:0% +individuals and interactions over +processes and tools so we've been + + align:start position:0% +processes and tools so we've been + + + align:start position:0% +processes and tools so we've been +talking to you a lot about process and + + align:start position:0% +talking to you a lot about process and + + + align:start position:0% +talking to you a lot about process and +tools uh for the first part of the + + align:start position:0% +tools uh for the first part of the + + + align:start position:0% +tools uh for the first part of the +semester now we're going to talk about + + align:start position:0% +semester now we're going to talk about + + + align:start position:0% +semester now we're going to talk about +individuals and and interactions between + + align:start position:0% +individuals and and interactions between + + + align:start position:0% +individuals and and interactions between +individuals so your team + + align:start position:0% +individuals so your team + + + align:start position:0% +individuals so your team +members all right what's a + + align:start position:0% +members all right what's a + + + align:start position:0% +members all right what's a +team anybody give me a working + + align:start position:0% +team anybody give me a working + + + align:start position:0% +team anybody give me a working +definition for what you'd call a te + + align:start position:0% + + + + align:start position:0% + +team what' you + + align:start position:0% +team what' you + + + align:start position:0% +team what' you +say a bunch of puppies is it a group of + + align:start position:0% +say a bunch of puppies is it a group of + + + align:start position:0% +say a bunch of puppies is it a group of +people is it just a group of people + + align:start position:0% +people is it just a group of people + + + align:start position:0% +people is it just a group of people +group of people work + + align:start position:0% +group of people work + + + align:start position:0% +group of people work +towards yes anything + + align:start position:0% +towards yes anything + + + align:start position:0% +towards yes anything +else so it's a collection of individuals + + align:start position:0% +else so it's a collection of individuals + + + align:start position:0% +else so it's a collection of individuals +so it's a group of people they're + + align:start position:0% +so it's a group of people they're + + + align:start position:0% +so it's a group of people they're +working toward a common purpose they + + align:start position:0% +working toward a common purpose they + + + align:start position:0% +working toward a common purpose they +have shared responsibility for common + + align:start position:0% +have shared responsibility for common + + + align:start position:0% +have shared responsibility for common +outcomes if one of those puppies trips + + align:start position:0% +outcomes if one of those puppies trips + + + align:start position:0% +outcomes if one of those puppies trips +that stick goes in another puppy's mouth + + align:start position:0% +that stick goes in another puppy's mouth + + + align:start position:0% +that stick goes in another puppy's mouth +and it hurts a lot um + + align:start position:0% +and it hurts a lot um + + + align:start position:0% +and it hurts a lot um +um so that and and I want you to to to + + align:start position:0% +um so that and and I want you to to to + + + align:start position:0% +um so that and and I want you to to to +keep that in mind shared responsibility + + align:start position:0% +keep that in mind shared responsibility + + + align:start position:0% +keep that in mind shared responsibility +common purpose common + + align:start position:0% +common purpose common + + + align:start position:0% +common purpose common +outcomes all right so um teams evolve + + align:start position:0% +outcomes all right so um teams evolve + + + align:start position:0% +outcomes all right so um teams evolve +over time and um the the little bit of + + align:start position:0% +over time and um the the little bit of + + + align:start position:0% +over time and um the the little bit of +research I'm going to talk about + + align:start position:0% +research I'm going to talk about + + + align:start position:0% +research I'm going to talk about +actually comes from um uh studying group + + align:start position:0% +actually comes from um uh studying group + + + align:start position:0% +actually comes from um uh studying group +behaviors but in the and this is all + + align:start position:0% +behaviors but in the and this is all + + + align:start position:0% +behaviors but in the and this is all +from about the 1960s and on up um in + + align:start position:0% +from about the 1960s and on up um in + + + align:start position:0% +from about the 1960s and on up um in +around the 2000s and I'll post this + + align:start position:0% +around the 2000s and I'll post this + + + align:start position:0% +around the 2000s and I'll post this +reading up um it was proven or was there + + align:start position:0% +reading up um it was proven or was there + + + align:start position:0% +reading up um it was proven or was there +was some study shown that this actually + + align:start position:0% +was some study shown that this actually + + + align:start position:0% +was some study shown that this actually +works for teams this does work for for + + align:start position:0% +works for teams this does work for for + + + align:start position:0% +works for teams this does work for for +people who have a common goal but as you + + align:start position:0% +people who have a common goal but as you + + + align:start position:0% +people who have a common goal but as you +get a bunch of people together and you + + align:start position:0% +get a bunch of people together and you + + + align:start position:0% +get a bunch of people together and you +get a small group of people together and + + align:start position:0% +get a small group of people together and + + + align:start position:0% +get a small group of people together and +in our terms we're talking a small group + + align:start position:0% +in our terms we're talking a small group + + + align:start position:0% +in our terms we're talking a small group +of people um 8 to 10 people um maybe a + + align:start position:0% +of people um 8 to 10 people um maybe a + + + align:start position:0% +of people um 8 to 10 people um maybe a +little bit bigger but about 10 people + + align:start position:0% +little bit bigger but about 10 people + + + align:start position:0% +little bit bigger but about 10 people +total um they're going to evolve based + + align:start position:0% +total um they're going to evolve based + + + align:start position:0% +total um they're going to evolve based +on those interpersonal relationships so + + align:start position:0% +on those interpersonal relationships so + + + align:start position:0% +on those interpersonal relationships so +how they know each other what they talk + + align:start position:0% +how they know each other what they talk + + + align:start position:0% +how they know each other what they talk +about how they talk about and their task + + align:start position:0% +about how they talk about and their task + + + align:start position:0% +about how they talk about and their task +behaviors so we're going to be talking + + align:start position:0% +behaviors so we're going to be talking + + + align:start position:0% +behaviors so we're going to be talking +about not the tasks that are do you are + + align:start position:0% +about not the tasks that are do you are + + + align:start position:0% +about not the tasks that are do you are +doing in your teams but the behaviors + + align:start position:0% +doing in your teams but the behaviors + + + align:start position:0% +doing in your teams but the behaviors +surrounding the tasks that you're doing + + align:start position:0% +surrounding the tasks that you're doing + + + align:start position:0% +surrounding the tasks that you're doing +it so um if you are working on a task if + + align:start position:0% +it so um if you are working on a task if + + + align:start position:0% +it so um if you are working on a task if +you are doing some coding how are you + + align:start position:0% +you are doing some coding how are you + + + align:start position:0% +you are doing some coding how are you +coding or who are you coding with how + + align:start position:0% +coding or who are you coding with how + + + align:start position:0% +coding or who are you coding with how +are you talking to other people about + + align:start position:0% +are you talking to other people about + + + align:start position:0% +are you talking to other people about +what you're coding and you can apply + + align:start position:0% +what you're coding and you can apply + + + align:start position:0% +what you're coding and you can apply +that to any other T any any task that + + align:start position:0% +that to any other T any any task that + + + align:start position:0% +that to any other T any any task that +you're doing in your teams there's a lot + + align:start position:0% +you're doing in your teams there's a lot + + + align:start position:0% +you're doing in your teams there's a lot +of different theories um actually + + align:start position:0% +of different theories um actually + + + align:start position:0% +of different theories um actually +Wikipedia is a pretty good um just a + + align:start position:0% +Wikipedia is a pretty good um just a + + + align:start position:0% +Wikipedia is a pretty good um just a +good nutshell of of what are all the + + align:start position:0% +good nutshell of of what are all the + + + align:start position:0% +good nutshell of of what are all the +different kinds of theories um and how + + align:start position:0% +different kinds of theories um and how + + + align:start position:0% +different kinds of theories um and how +different kind of models we can use to + + align:start position:0% +different kind of models we can use to + + + align:start position:0% +different kind of models we can use to +describe how groups talk to each other + + align:start position:0% +describe how groups talk to each other + + + align:start position:0% +describe how groups talk to each other +and how groups evolve um but they all + + align:start position:0% +and how groups evolve um but they all + + + align:start position:0% +and how groups evolve um but they all +come down to these things there's a + + align:start position:0% +come down to these things there's a + + + align:start position:0% +come down to these things there's a +period of getting to know each other um + + align:start position:0% +period of getting to know each other um + + + align:start position:0% +period of getting to know each other um +there's a period of experiencing + + align:start position:0% +there's a period of experiencing + + + align:start position:0% +there's a period of experiencing +conflict and there's both positive and + + align:start position:0% +conflict and there's both positive and + + + align:start position:0% +conflict and there's both positive and +negative conflict when you're talking + + align:start position:0% +negative conflict when you're talking + + + align:start position:0% +negative conflict when you're talking +with each other your roles shift based + + align:start position:0% +with each other your roles shift based + + + align:start position:0% +with each other your roles shift based +on changing knowledge and changing + + align:start position:0% +on changing knowledge and changing + + + align:start position:0% +on changing knowledge and changing +experience and hopefully at some point + + align:start position:0% +experience and hopefully at some point + + + align:start position:0% +experience and hopefully at some point +there's some kind of consensus there's + + align:start position:0% +there's some kind of consensus there's + + + align:start position:0% +there's some kind of consensus there's +some kind of moving forward decisions + + align:start position:0% +some kind of moving forward decisions + + + align:start position:0% +some kind of moving forward decisions +happen here uh the point is though what + + align:start position:0% +happen here uh the point is though what + + + align:start position:0% +happen here uh the point is though what +kind of decisions get made are they + + align:start position:0% +kind of decisions get made are they + + + align:start position:0% +kind of decisions get made are they +effective decisions um or they + + align:start position:0% +effective decisions um or they + + + align:start position:0% +effective decisions um or they +ineffective + + align:start position:0% +ineffective + + + align:start position:0% +ineffective +unproven they get made because you just + + align:start position:0% +unproven they get made because you just + + + align:start position:0% +unproven they get made because you just +have to make them and you have to move + + align:start position:0% +have to make them and you have to move + + + align:start position:0% +have to make them and you have to move +move on um we're hoping is that by + + align:start position:0% +move on um we're hoping is that by + + + align:start position:0% +move on um we're hoping is that by +analyzing how your teams work you can + + align:start position:0% +analyzing how your teams work you can + + + align:start position:0% +analyzing how your teams work you can +then move towards having some effective + + align:start position:0% +then move towards having some effective + + + align:start position:0% +then move towards having some effective +decision decision + + align:start position:0% +decision decision + + + align:start position:0% +decision decision +making um so one so the model that we're + + align:start position:0% +making um so one so the model that we're + + + align:start position:0% +making um so one so the model that we're +going to talk about um is tuckman's + + align:start position:0% +going to talk about um is tuckman's + + + align:start position:0% +going to talk about um is tuckman's +model from 65 it's got four phases um + + align:start position:0% +model from 65 it's got four phases um + + + align:start position:0% +model from 65 it's got four phases um +forming norming storming performing it's + + align:start position:0% +forming norming storming performing it's + + + align:start position:0% +forming norming storming performing it's +very cutesy you get it's gets used in + + align:start position:0% +very cutesy you get it's gets used in + + + align:start position:0% +very cutesy you get it's gets used in +training sessions a lot um it can just + + align:start position:0% +training sessions a lot um it can just + + + align:start position:0% +training sessions a lot um it can just +be something that you can just spit out + + align:start position:0% +be something that you can just spit out + + + align:start position:0% +be something that you can just spit out +and say and someone says oh you're smart + + align:start position:0% +and say and someone says oh you're smart + + + align:start position:0% +and say and someone says oh you're smart +you know that that that model but maybe + + align:start position:0% +you know that that that model but maybe + + + align:start position:0% +you know that that that model but maybe +you don't know everything behind it um I + + align:start position:0% +you don't know everything behind it um I + + + align:start position:0% +you don't know everything behind it um I +might be more the you're smart but maybe + + align:start position:0% +might be more the you're smart but maybe + + + align:start position:0% +might be more the you're smart but maybe +you don't know more everything behind it + + align:start position:0% +you don't know more everything behind it + + + align:start position:0% +you don't know more everything behind it +I'm still learning about how this works + + align:start position:0% +I'm still learning about how this works + + + align:start position:0% +I'm still learning about how this works +um but each phase has items you you can + + align:start position:0% +um but each phase has items you you can + + + align:start position:0% +um but each phase has items you you can +identify and more useful for us is this + + align:start position:0% +identify and more useful for us is this + + + align:start position:0% +identify and more useful for us is this +is a model you can use to figure out + + align:start position:0% +is a model you can use to figure out + + + align:start position:0% +is a model you can use to figure out +where your team is right now um what + + align:start position:0% +where your team is right now um what + + + align:start position:0% +where your team is right now um what +phase are you in so you can then make + + align:start position:0% +phase are you in so you can then make + + + align:start position:0% +phase are you in so you can then make +decisions about where you need to go and + + align:start position:0% +decisions about where you need to go and + + + align:start position:0% +decisions about where you need to go and +how you need to work together + + align:start position:0% + + + + align:start position:0% + +better so um the forming uh phase of it + + align:start position:0% +better so um the forming uh phase of it + + + align:start position:0% +better so um the forming uh phase of it +this is when you first start getting + + align:start position:0% +this is when you first start getting + + + align:start position:0% +this is when you first start getting +together everyone wants to be friendly + + align:start position:0% +together everyone wants to be friendly + + + align:start position:0% +together everyone wants to be friendly +um everyone wants to get along and to be + + align:start position:0% +um everyone wants to get along and to be + + + align:start position:0% +um everyone wants to get along and to be +accepted with each other um there might + + align:start position:0% +accepted with each other um there might + + + align:start position:0% +accepted with each other um there might +be some serious problems from the get-go + + align:start position:0% +be some serious problems from the get-go + + + align:start position:0% +be some serious problems from the get-go +but they're usually avoided um and the + + align:start position:0% +but they're usually avoided um and the + + + align:start position:0% +but they're usually avoided um and the +team learns about challenges and goals + + align:start position:0% +team learns about challenges and goals + + + align:start position:0% +team learns about challenges and goals +but not much gets done um there's no + + align:start position:0% +but not much gets done um there's no + + + align:start position:0% +but not much gets done um there's no +real task completion going on in this + + align:start position:0% +real task completion going on in this + + + align:start position:0% +real task completion going on in this +stage um has everybody seen this can + + align:start position:0% +stage um has everybody seen this can + + + align:start position:0% +stage um has everybody seen this can +when you think about your previous teams + + align:start position:0% +when you think about your previous teams + + + align:start position:0% +when you think about your previous teams +you've been in this stage right when you + + align:start position:0% +you've been in this stage right when you + + + align:start position:0% +you've been in this stage right when you +first got + + align:start position:0% +first got + + + align:start position:0% +first got +together so project two project three + + align:start position:0% +together so project two project three + + + align:start position:0% +together so project two project three +I'm going to talk I want to ask you some + + align:start position:0% +I'm going to talk I want to ask you some + + + align:start position:0% +I'm going to talk I want to ask you some +questions about projects two and three + + align:start position:0% +questions about projects two and three + + + align:start position:0% +questions about projects two and three +as we go forward all + + align:start position:0% +as we go forward all + + + align:start position:0% +as we go forward all +right that's a happy stage then storming + + align:start position:0% +right that's a happy stage then storming + + + align:start position:0% +right that's a happy stage then storming +happens people are able to express + + align:start position:0% +happens people are able to express + + + align:start position:0% +happens people are able to express +discontent there actually might have + + align:start position:0% +discontent there actually might have + + + align:start position:0% +discontent there actually might have +been discontent in phase one but it + + align:start position:0% +been discontent in phase one but it + + + align:start position:0% +been discontent in phase one but it +actually wasn't being it wasn't being + + align:start position:0% +actually wasn't being it wasn't being + + + align:start position:0% +actually wasn't being it wasn't being +expressed in some form in phase two it's + + align:start position:0% +expressed in some form in phase two it's + + + align:start position:0% +expressed in some form in phase two it's +being expressed but how it's being + + align:start position:0% +being expressed but how it's being + + + align:start position:0% +being expressed but how it's being +Express can be kind of different so it + + align:start position:0% +Express can be kind of different so it + + + align:start position:0% +Express can be kind of different so it +could be someone actively saying no + + align:start position:0% +could be someone actively saying no + + + align:start position:0% +could be someone actively saying no +you're wrong that's stupid um it could + + align:start position:0% +you're wrong that's stupid um it could + + + align:start position:0% +you're wrong that's stupid um it could +be someone not talking but they're + + align:start position:0% +be someone not talking but they're + + + align:start position:0% +be someone not talking but they're +feeling the same thing and they're + + align:start position:0% +feeling the same thing and they're + + + align:start position:0% +feeling the same thing and they're +thinking about the same thing it's the + + align:start position:0% +thinking about the same thing it's the + + + align:start position:0% +thinking about the same thing it's the +same kind of discon happen umin opinions + + align:start position:0% +same kind of discon happen umin opinions + + + align:start position:0% +same kind of discon happen umin opinions +tend to get challenged um it can be + + align:start position:0% +tend to get challenged um it can be + + + align:start position:0% +tend to get challenged um it can be +contentious it can be + + align:start position:0% +contentious it can be + + + align:start position:0% +contentious it can be +unpleasant um in order to advance past + + align:start position:0% +unpleasant um in order to advance past + + + align:start position:0% +unpleasant um in order to advance past +this stage what your team really needs + + align:start position:0% +this stage what your team really needs + + + align:start position:0% +this stage what your team really needs +is tolerance and patience I'm just to + + align:start position:0% +is tolerance and patience I'm just to + + + align:start position:0% +is tolerance and patience I'm just to +kind of get through it but even more + + align:start position:0% +kind of get through it but even more + + + align:start position:0% +kind of get through it but even more +important you need to establish lines of + + align:start position:0% +important you need to establish lines of + + + align:start position:0% +important you need to establish lines of +trust and open communication to get + + align:start position:0% +trust and open communication to get + + + align:start position:0% +trust and open communication to get +through the stage and this is where this + + align:start position:0% +through the stage and this is where this + + + align:start position:0% +through the stage and this is where this +is what we've been doing for the past + + align:start position:0% +is what we've been doing for the past + + + align:start position:0% +is what we've been doing for the past +first of the semester is creating + + align:start position:0% +first of the semester is creating + + + align:start position:0% +first of the semester is creating +processes we've been giving you some + + align:start position:0% +processes we've been giving you some + + + align:start position:0% +processes we've been giving you some +tools that you can use so then you can + + align:start position:0% +tools that you can use so then you can + + + align:start position:0% +tools that you can use so then you can +then create those processes in your + + align:start position:0% +then create those processes in your + + + align:start position:0% +then create those processes in your +teams so just a quick hand raise from + + align:start position:0% +teams so just a quick hand raise from + + + align:start position:0% +teams so just a quick hand raise from +teams + + align:start position:0% +teams + + + align:start position:0% +teams +um does anybody think that they are in + + align:start position:0% +um does anybody think that they are in + + + align:start position:0% +um does anybody think that they are in +this stage right + + align:start position:0% +this stage right + + + align:start position:0% +this stage right +now do you think in your team you are + + align:start position:0% +now do you think in your team you are + + + align:start position:0% +now do you think in your team you are +currently you're expressing discontent + + align:start position:0% +currently you're expressing discontent + + + align:start position:0% +currently you're expressing discontent +you are creating processes you don't + + align:start position:0% +you are creating processes you don't + + + align:start position:0% +you are creating processes you don't +have processes yet but you're figuring + + align:start position:0% +have processes yet but you're figuring + + + align:start position:0% +have processes yet but you're figuring +out what your processes might + + align:start position:0% + + + + align:start position:0% + +be maybe what do you say you're not sure + + align:start position:0% +be maybe what do you say you're not sure + + + align:start position:0% +be maybe what do you say you're not sure +okay all right + + align:start position:0% +okay all right + + + align:start position:0% +okay all right +um next up norming so this is where have + + align:start position:0% +um next up norming so this is where have + + + align:start position:0% +um next up norming so this is where have +those processes um individuals start + + align:start position:0% +those processes um individuals start + + + align:start position:0% +those processes um individuals start +giving up their own ideas and goals + + align:start position:0% +giving up their own ideas and goals + + + align:start position:0% +giving up their own ideas and goals +you're moving you're actually moving + + align:start position:0% +you're moving you're actually moving + + + align:start position:0% +you're moving you're actually moving +towards a team goal right now and people + + align:start position:0% +towards a team goal right now and people + + + align:start position:0% +towards a team goal right now and people +are starting to take responsibility and + + align:start position:0% +are starting to take responsibility and + + + align:start position:0% +are starting to take responsibility and +rules are established okay comparing + + align:start position:0% +rules are established okay comparing + + + align:start position:0% +rules are established okay comparing +storming to norming raise your hands if + + align:start position:0% +storming to norming raise your hands if + + + align:start position:0% +storming to norming raise your hands if +you think you're in norming your team is + + align:start position:0% +you think you're in norming your team is + + + align:start position:0% +you think you're in norming your team is +in norming right + + align:start position:0% + + + + align:start position:0% + +now okay yeah all right now raise your + + align:start position:0% +now okay yeah all right now raise your + + + align:start position:0% +now okay yeah all right now raise your +hands if you think your team is in + + align:start position:0% +hands if you think your team is in + + + align:start position:0% +hands if you think your team is in +storming right + + align:start position:0% + + + + align:start position:0% + +now + + align:start position:0% +now + + + align:start position:0% +now +okay um + + align:start position:0% + + + + align:start position:0% + +all right so is anybody performing are + + align:start position:0% +all right so is anybody performing are + + + align:start position:0% +all right so is anybody performing are +you functioning as a unit efficiently + + align:start position:0% +you functioning as a unit efficiently + + + align:start position:0% +you functioning as a unit efficiently +are your team members already + + align:start position:0% +are your team members already + + + align:start position:0% +are your team members already +autonomous is descent expected and + + align:start position:0% +autonomous is descent expected and + + + align:start position:0% +autonomous is descent expected and +addressed right now this is where you + + align:start position:0% +addressed right now this is where you + + + align:start position:0% +addressed right now this is where you +want to get + + align:start position:0% +want to get + + + align:start position:0% +want to get +to you probably aren't this far yet my + + align:start position:0% +to you probably aren't this far yet my + + + align:start position:0% +to you probably aren't this far yet my +bets you're probably somewhere in the in + + align:start position:0% +bets you're probably somewhere in the in + + + align:start position:0% +bets you're probably somewhere in the in +the storming area of things maybe + + align:start position:0% +the storming area of things maybe + + + align:start position:0% +the storming area of things maybe +getting close to the norming area of + + align:start position:0% +getting close to the norming area of + + + align:start position:0% +getting close to the norming area of +things basically you're still trying to + + align:start position:0% +things basically you're still trying to + + + align:start position:0% +things basically you're still trying to +you're still talking to each other + + align:start position:0% +you're still talking to each other + + + align:start position:0% +you're still talking to each other +you're still trying to figure out what + + align:start position:0% +you're still trying to figure out what + + + align:start position:0% +you're still trying to figure out what +are the the different ways of + + align:start position:0% +are the the different ways of + + + align:start position:0% +are the the different ways of +communicating with each other um what + + align:start position:0% +communicating with each other um what + + + align:start position:0% +communicating with each other um what +are the the different um processes and + + align:start position:0% +are the the different um processes and + + + align:start position:0% +are the the different um processes and +rules you might + + align:start position:0% + + + + align:start position:0% + +have and you might not get this far uh + + align:start position:0% +have and you might not get this far uh + + + align:start position:0% +have and you might not get this far uh +in class in class by the end of the + + align:start position:0% +in class in class by the end of the + + + align:start position:0% +in class in class by the end of the +semester you might not be uh fully + + align:start position:0% +semester you might not be uh fully + + + align:start position:0% +semester you might not be uh fully +efficient by the end of the the end of + + align:start position:0% +efficient by the end of the the end of + + + align:start position:0% +efficient by the end of the the end of +the class and that's + + align:start position:0% +the class and that's + + + align:start position:0% +the class and that's +okay but if you are it's kind of + + align:start position:0% +okay but if you are it's kind of + + + align:start position:0% +okay but if you are it's kind of +cool so um the model in practice tends + + align:start position:0% +cool so um the model in practice tends + + + align:start position:0% +cool so um the model in practice tends +to be it's nonlinear it's it gets talked + + align:start position:0% +to be it's nonlinear it's it gets talked + + + align:start position:0% +to be it's nonlinear it's it gets talked +about and it was originally um + + align:start position:0% +about and it was originally um + + + align:start position:0% +about and it was originally um +established as a you go from here to + + align:start position:0% +established as a you go from here to + + + align:start position:0% +established as a you go from here to +here to here to here you go through the + + align:start position:0% +here to here to here you go through the + + + align:start position:0% +here to here to here you go through the +phases at the end of the thing you're + + align:start position:0% +phases at the end of the thing you're + + + align:start position:0% +phases at the end of the thing you're +done your team's awesome go you um what + + align:start position:0% +done your team's awesome go you um what + + + align:start position:0% +done your team's awesome go you um what +we actually see in process is that teams + + align:start position:0% +we actually see in process is that teams + + + align:start position:0% +we actually see in process is that teams +tend to they get in the forming they go + + align:start position:0% +tend to they get in the forming they go + + + align:start position:0% +tend to they get in the forming they go +in this circle where they go from from + + align:start position:0% +in this circle where they go from from + + + align:start position:0% +in this circle where they go from from +having some issues figuring out how to + + align:start position:0% +having some issues figuring out how to + + + align:start position:0% +having some issues figuring out how to +how to deal with those issues establish + + align:start position:0% +how to deal with those issues establish + + + align:start position:0% +how to deal with those issues establish +some rules all right we're do really + + align:start position:0% +some rules all right we're do really + + + align:start position:0% +some rules all right we're do really +well again new challenge comes up we're + + align:start position:0% +well again new challenge comes up we're + + + align:start position:0% +well again new challenge comes up we're +back into we're back into storming we're + + align:start position:0% +back into we're back into storming we're + + + align:start position:0% +back into we're back into storming we're +we we are we've put ourselves in a + + align:start position:0% +we we are we've put ourselves in a + + + align:start position:0% +we we are we've put ourselves in a +position where we don't know how to talk + + align:start position:0% +position where we don't know how to talk + + + align:start position:0% +position where we don't know how to talk +to each other or we don't know how to + + align:start position:0% +to each other or we don't know how to + + + align:start position:0% +to each other or we don't know how to +communicate with each other + + align:start position:0% + + + + align:start position:0% + +so there's some problems with the with + + align:start position:0% +so there's some problems with the with + + + align:start position:0% +so there's some problems with the with +the model this is really a descriptive + + align:start position:0% +the model this is really a descriptive + + + align:start position:0% +the model this is really a descriptive +model it's a way it's a tool for us to + + align:start position:0% +model it's a way it's a tool for us to + + + align:start position:0% +model it's a way it's a tool for us to +use to see how things are going it's + + align:start position:0% +use to see how things are going it's + + + align:start position:0% +use to see how things are going it's +basically a way to evaluate symptoms + + align:start position:0% +basically a way to evaluate symptoms + + + align:start position:0% +basically a way to evaluate symptoms +um but there's no triggers in the model + + align:start position:0% +um but there's no triggers in the model + + + align:start position:0% +um but there's no triggers in the model +we don't know when those things happen + + align:start position:0% +we don't know when those things happen + + + align:start position:0% +we don't know when those things happen +when does it when does your team switch + + align:start position:0% +when does it when does your team switch + + + align:start position:0% +when does it when does your team switch +from storming to norming so this is what + + align:start position:0% +from storming to norming so this is what + + + align:start position:0% +from storming to norming so this is what +I'd like you to do in your in your teams + + align:start position:0% +I'd like you to do in your in your teams + + + align:start position:0% +I'd like you to do in your in your teams +just take a couple minutes talk about um + + align:start position:0% +just take a couple minutes talk about um + + + align:start position:0% +just take a couple minutes talk about um +talk about your previous teams you've + + align:start position:0% +talk about your previous teams you've + + + align:start position:0% +talk about your previous teams you've +been on talk about the team you're on + + align:start position:0% +been on talk about the team you're on + + + align:start position:0% +been on talk about the team you're on +now + + align:start position:0% +now + + + align:start position:0% +now +when do you think your team would move + + align:start position:0% +when do you think your team would move + + + align:start position:0% +when do you think your team would move +from stage to stage and how could a team + + align:start position:0% +from stage to stage and how could a team + + + align:start position:0% +from stage to stage and how could a team +move + + align:start position:0% +move + + + align:start position:0% +move +intentionally so and in particular think + + align:start position:0% +intentionally so and in particular think + + + align:start position:0% +intentionally so and in particular think +about that storming dorming part of it + + align:start position:0% +about that storming dorming part of it + + + align:start position:0% +about that storming dorming part of it +so what is it going to take for your + + align:start position:0% +so what is it going to take for your + + + align:start position:0% +so what is it going to take for your +team right now or what happened in your + + align:start position:0% +team right now or what happened in your + + + align:start position:0% +team right now or what happened in your +team right now to go from we are having + + align:start position:0% +team right now to go from we are having + + + align:start position:0% +team right now to go from we are having +some some difficulty talking with each + + align:start position:0% +some some difficulty talking with each + + + align:start position:0% +some some difficulty talking with each +other we're we're we have a bunch of + + align:start position:0% +other we're we're we have a bunch of + + + align:start position:0% +other we're we're we have a bunch of +opinions two we're on on the same page + + align:start position:0% +opinions two we're on on the same page + + + align:start position:0% +opinions two we're on on the same page +take three minutes just just one thing I + + align:start position:0% +take three minutes just just one thing I + + + align:start position:0% +take three minutes just just one thing I +want to chime in there's a very very + + align:start position:0% +want to chime in there's a very very + + + align:start position:0% +want to chime in there's a very very +good chance that your team actually is + + align:start position:0% +good chance that your team actually is + + + align:start position:0% +good chance that your team actually is +still in forming stage and one of the + + align:start position:0% +still in forming stage and one of the + + + align:start position:0% +still in forming stage and one of the +reasons why no one like very few of you + + align:start position:0% +reasons why no one like very few of you + + + align:start position:0% +reasons why no one like very few of you +might have put up your hands that you + + align:start position:0% +might have put up your hands that you + + + align:start position:0% +might have put up your hands that you +don't actually want to express dissent + + align:start position:0% +don't actually want to express dissent + + + align:start position:0% +don't actually want to express dissent +which is exactly the situation that you + + align:start position:0% +which is exactly the situation that you + + + align:start position:0% +which is exactly the situation that you +get in forming stage um you know it's it + + align:start position:0% +get in forming stage um you know it's it + + + align:start position:0% +get in forming stage um you know it's it +is uncomfortable but hopefully there you + + align:start position:0% +is uncomfortable but hopefully there you + + + align:start position:0% +is uncomfortable but hopefully there you +can logically see the benefits of being + + align:start position:0% +can logically see the benefits of being + + + align:start position:0% +can logically see the benefits of being +in a team where you can talk about the + + align:start position:0% +in a team where you can talk about the + + + align:start position:0% +in a team where you can talk about the +things that you disagree with right so + + align:start position:0% +things that you disagree with right so + + + align:start position:0% +things that you disagree with right so +um so it's possible that you are still + + align:start position:0% +um so it's possible that you are still + + + align:start position:0% +um so it's possible that you are still +informing and you know it's good to + + align:start position:0% +informing and you know it's good to + + + align:start position:0% +informing and you know it's good to +identify your teams as okay this is + + align:start position:0% +identify your teams as okay this is + + + align:start position:0% +identify your teams as okay this is +normal evolution of a team and that's + + align:start position:0% +normal evolution of a team and that's + + + align:start position:0% +normal evolution of a team and that's +where our team is at right now so talk + + align:start position:0% +where our team is at right now so talk + + + align:start position:0% +where our team is at right now so talk +about it among your team so take three + + align:start position:0% +about it among your team so take three + + + align:start position:0% +about it among your team so take three +minutes just talking your teams and I'm + + align:start position:0% +minutes just talking your teams and I'm + + + align:start position:0% +minutes just talking your teams and I'm +gonna ask you some questions when we're + + align:start position:0% + + + + align:start position:0% + +done okay + + align:start position:0% + + + + align:start position:0% + +so each group give me a + + align:start position:0% +so each group give me a + + + align:start position:0% +so each group give me a +something you talked about about what + + align:start position:0% +something you talked about about what + + + align:start position:0% +something you talked about about what +are the what are the triggers what are + + align:start position:0% +are the what are the triggers what are + + + align:start position:0% +are the what are the triggers what are +the things you saw as you moved just let + + align:start position:0% +the things you saw as you moved just let + + + align:start position:0% +the things you saw as you moved just let +me know which phases you're talking + + align:start position:0% +me know which phases you're talking + + + align:start position:0% +me know which phases you're talking +about so go + + align:start position:0% + + + + align:start position:0% + +ahead how do you know or what's the what + + align:start position:0% +ahead how do you know or what's the what + + + align:start position:0% +ahead how do you know or what's the what +caused that + + align:start position:0% +caused that + + + align:start position:0% +caused that +what caused you to get there do you + + align:start position:0% +what caused you to get there do you + + + align:start position:0% +what caused you to get there do you +think we got a lot of + + align:start position:0% + + + + align:start position:0% + +theame we + + align:start position:0% +theame we + + + align:start position:0% +theame we +had the + + align:start position:0% +had the + + + align:start position:0% +had the +reason closer to because we just + + align:start position:0% +reason closer to because we just + + + align:start position:0% +reason closer to because we just +and Pi off and Mar + + align:start position:0% +and Pi off and Mar + + + align:start position:0% +and Pi off and Mar +done + + align:start position:0% + + + + align:start position:0% + +F okay + + align:start position:0% + + + + align:start position:0% + +oning + + align:start position:0% + + + + align:start position:0% + +anding because still working + + align:start position:0% + + + + align:start position:0% + +lision all right so it's big + + align:start position:0% +lision all right so it's big + + + align:start position:0% +lision all right so it's big +decisions how big are those two + + align:start position:0% +decisions how big are those two + + + align:start position:0% +decisions how big are those two +teams four and four okay so somebody + + align:start position:0% +teams four and four okay so somebody + + + align:start position:0% +teams four and four okay so somebody +else + + align:start position:0% +else + + + align:start position:0% +else +next a trigger that you saw that that + + align:start position:0% +next a trigger that you saw that that + + + align:start position:0% +next a trigger that you saw that that +made you go from one stage to the + + align:start position:0% +made you go from one stage to the + + + align:start position:0% +made you go from one stage to the +other um I think we're also in the place + + align:start position:0% +other um I think we're also in the place + + + align:start position:0% +other um I think we're also in the place +as a team we're moving from storming to + + align:start position:0% +as a team we're moving from storming to + + + align:start position:0% +as a team we're moving from storming to +norming and part of that a trigger was + + align:start position:0% +norming and part of that a trigger was + + + align:start position:0% +norming and part of that a trigger was +solidifying our game or working on + + align:start position:0% +solidifying our game or working on + + + align:start position:0% +solidifying our game or working on +solidifying our game idea because at + + align:start position:0% +solidifying our game idea because at + + + align:start position:0% +solidifying our game idea because at +this point while we all recognize one of + + align:start position:0% +this point while we all recognize one of + + + align:start position:0% +this point while we all recognize one of +build get of team we all have different + + align:start position:0% +build get of team we all have different + + + align:start position:0% +build get of team we all have different +ideas of like what this game should be + + align:start position:0% +ideas of like what this game should be + + + align:start position:0% +ideas of like what this game should be +and as we solidifying our game we're + + align:start position:0% +and as we solidifying our game we're + + + align:start position:0% +and as we solidifying our game we're +also getting ourselves in line with like + + align:start position:0% +also getting ourselves in line with like + + + align:start position:0% +also getting ourselves in line with like +what we're actually doing and how we're + + align:start position:0% +what we're actually doing and how we're + + + align:start position:0% +what we're actually doing and how we're +going to make it happen Okay so do you + + align:start position:0% +going to make it happen Okay so do you + + + align:start position:0% +going to make it happen Okay so do you +think that the task of solidifying the + + align:start position:0% +think that the task of solidifying the + + + align:start position:0% +think that the task of solidifying the +game ID is helping you because there's + + align:start position:0% +game ID is helping you because there's + + + align:start position:0% +game ID is helping you because there's +this big decision you have to make is + + align:start position:0% +this big decision you have to make is + + + align:start position:0% +this big decision you have to make is +that helping + + align:start position:0% +that helping + + + align:start position:0% +that helping +you move like work as a team it's not + + align:start position:0% +you move like work as a team it's not + + + align:start position:0% +you move like work as a team it's not +getting in your way I think it's the + + align:start position:0% +getting in your way I think it's the + + + align:start position:0% +getting in your way I think it's the +fact that like as we're doing this we + + align:start position:0% +fact that like as we're doing this we + + + align:start position:0% +fact that like as we're doing this we +have a lot of we defitely have to s for + + align:start position:0% +have a lot of we defitely have to s for + + + align:start position:0% +have a lot of we defitely have to s for +like you know conflict in our team where + + align:start position:0% +like you know conflict in our team where + + + align:start position:0% +like you know conflict in our team where +people were shatting out different ideas + + align:start position:0% +people were shatting out different ideas + + + align:start position:0% +people were shatting out different ideas +and like trying to work through it and + + align:start position:0% +and like trying to work through it and + + + align:start position:0% +and like trying to work through it and +at first we weren't doing the best job + + align:start position:0% +at first we weren't doing the best job + + + align:start position:0% +at first we weren't doing the best job +of like getting those ideas and working + + align:start position:0% +of like getting those ideas and working + + + align:start position:0% +of like getting those ideas and working +through them but I see that now we're + + align:start position:0% +through them but I see that now we're + + + align:start position:0% +through them but I see that now we're +doing a much better job of understanding + + align:start position:0% +doing a much better job of understanding + + + align:start position:0% +doing a much better job of understanding +each other and like seeing how it fits + + align:start position:0% +each other and like seeing how it fits + + + align:start position:0% +each other and like seeing how it fits +into the bigger picture okay cool next + + align:start position:0% +into the bigger picture okay cool next + + + align:start position:0% +into the bigger picture okay cool next +team a triggering moment that you saw in + + align:start position:0% +team a triggering moment that you saw in + + + align:start position:0% +team a triggering moment that you saw in +this team or previous teams so we had a + + align:start position:0% +this team or previous teams so we had a + + + align:start position:0% +this team or previous teams so we had a +bigger callar team at first and I think + + align:start position:0% +bigger callar team at first and I think + + + align:start position:0% +bigger callar team at first and I think +that decid split up um was a way that + + align:start position:0% +that decid split up um was a way that + + + align:start position:0% +that decid split up um was a way that +helped us jump from foring to storming + + align:start position:0% +helped us jump from foring to storming + + + align:start position:0% +helped us jump from foring to storming +um because we needed to sort of storm to + + align:start position:0% +um because we needed to sort of storm to + + + align:start position:0% +um because we needed to sort of storm to +get our team to get two different ideas + + align:start position:0% +get our team to get two different ideas + + + align:start position:0% +get our team to get two different ideas +so + + align:start position:0% +so + + + align:start position:0% +so +uh ideas in terms of where our gam go in + + align:start position:0% +uh ideas in terms of where our gam go in + + + align:start position:0% +uh ideas in terms of where our gam go in +theor session so it's basically just + + align:start position:0% +theor session so it's basically just + + + align:start position:0% +theor session so it's basically just +it's reducing the number of opinions + + align:start position:0% +it's reducing the number of opinions + + + align:start position:0% +it's reducing the number of opinions +really + + align:start position:0% + + + + align:start position:0% + +right on that is share with your + + align:start position:0% + + + + align:start position:0% + +people so with our game I think getting + + align:start position:0% +people so with our game I think getting + + + align:start position:0% +people so with our game I think getting +us to norming was really they talked + + align:start position:0% +us to norming was really they talked + + + align:start position:0% +us to norming was really they talked +about assigning uh tasks but also just + + align:start position:0% +about assigning uh tasks but also just + + + align:start position:0% +about assigning uh tasks but also just +the accountability aspect because + + align:start position:0% +the accountability aspect because + + + align:start position:0% +the accountability aspect because +instead of spending time arguing we + + align:start position:0% +instead of spending time arguing we + + + align:start position:0% +instead of spending time arguing we +already kind of have a designated person + + align:start position:0% +already kind of have a designated person + + + align:start position:0% +already kind of have a designated person +or a couple of people who are + + align:start position:0% +or a couple of people who are + + + align:start position:0% +or a couple of people who are +accountable for different things which + + align:start position:0% +accountable for different things which + + + align:start position:0% +accountable for different things which +allows us to just kind of not + + align:start position:0% + + + + align:start position:0% + +arguing so that's like certain people + + align:start position:0% +arguing so that's like certain people + + + align:start position:0% +arguing so that's like certain people +have different like they own some + + align:start position:0% +have different like they own some + + + align:start position:0% +have different like they own some +subtask or own sub roles yes okay cool + + align:start position:0% +subtask or own sub roles yes okay cool + + + align:start position:0% +subtask or own sub roles yes okay cool +in the back what do you think so I guess + + align:start position:0% +in the back what do you think so I guess + + + align:start position:0% +in the back what do you think so I guess +what got us over to storming was meeting + + align:start position:0% +what got us over to storming was meeting + + + align:start position:0% +what got us over to storming was meeting +together as a team to make design + + align:start position:0% +together as a team to make design + + + align:start position:0% +together as a team to make design +decisions are sort of like what has been + + align:start position:0% +decisions are sort of like what has been + + + align:start position:0% +decisions are sort of like what has been +said there and I think that the next + + align:start position:0% +said there and I think that the next + + + align:start position:0% +said there and I think that the next +step for bringing us over to norming + + align:start position:0% +step for bringing us over to norming + + + align:start position:0% +step for bringing us over to norming +would be like actually getting everyone + + align:start position:0% +would be like actually getting everyone + + + align:start position:0% +would be like actually getting everyone +to participate in design decisions cuz + + align:start position:0% +to participate in design decisions cuz + + + align:start position:0% +to participate in design decisions cuz +like people have both not shown up and + + align:start position:0% +like people have both not shown up and + + + align:start position:0% +like people have both not shown up and +not particularly shown interest in + + align:start position:0% +not particularly shown interest in + + + align:start position:0% +not particularly shown interest in +getting things going so getting everyone + + align:start position:0% +getting things going so getting everyone + + + align:start position:0% +getting things going so getting everyone +on board even is all right that's a so + + align:start position:0% +on board even is all right that's a so + + + align:start position:0% +on board even is all right that's a so +that's a big one that's a that's a huge + + align:start position:0% +that's a big one that's a that's a huge + + + align:start position:0% +that's a big one that's a that's a huge +difficulty with um especially with + + align:start position:0% +difficulty with um especially with + + + align:start position:0% +difficulty with um especially with +student projects you've got all these + + align:start position:0% +student projects you've got all these + + + align:start position:0% +student projects you've got all these +other things going on around you um do + + align:start position:0% +other things going on around you um do + + + align:start position:0% +other things going on around you um do +you think you need everyone to + + align:start position:0% +you think you need everyone to + + + align:start position:0% +you think you need everyone to +contribute to the design or do you need + + align:start position:0% +contribute to the design or do you need + + + align:start position:0% +contribute to the design or do you need +everyone to be on board with the + + align:start position:0% +everyone to be on board with the + + + align:start position:0% +everyone to be on board with the +design uh + + align:start position:0% +design uh + + + align:start position:0% +design uh +so I understand like some people just + + align:start position:0% +so I understand like some people just + + + align:start position:0% +so I understand like some people just +are are less interested in having deep + + align:start position:0% +are are less interested in having deep + + + align:start position:0% +are are less interested in having deep +discussions about the design of the game + + align:start position:0% +discussions about the design of the game + + + align:start position:0% +discussions about the design of the game +but getting everyone to both be aware + + align:start position:0% +but getting everyone to both be aware + + + align:start position:0% +but getting everyone to both be aware +and willing to participate when they + + align:start position:0% +and willing to participate when they + + + align:start position:0% +and willing to participate when they +need to okay CU yeah there's there's + + align:start position:0% +need to okay CU yeah there's there's + + + align:start position:0% +need to okay CU yeah there's there's +important conversations being done that + + align:start position:0% +important conversations being done that + + + align:start position:0% +important conversations being done that +if they're not there when it happens + + align:start position:0% +if they're not there when it happens + + + align:start position:0% +if they're not there when it happens +they're not going to know where the + + align:start position:0% +they're not going to know where the + + + align:start position:0% +they're not going to know where the +status of the game is yeah and they just + + align:start position:0% +status of the game is yeah and they just + + + align:start position:0% +status of the game is yeah and they just +need to be like willing to participate + + align:start position:0% +need to be like willing to participate + + + align:start position:0% +need to be like willing to participate +like if they're not there take the step + + align:start position:0% +like if they're not there take the step + + + align:start position:0% +like if they're not there take the step +of oh what' you guys talk about I'm + + align:start position:0% +of oh what' you guys talk about I'm + + + align:start position:0% +of oh what' you guys talk about I'm +interested in knowing I want to okay + + align:start position:0% +interested in knowing I want to okay + + + align:start position:0% +interested in knowing I want to okay +cool thank you for that lead because + + align:start position:0% +cool thank you for that lead because + + + align:start position:0% +cool thank you for that lead because +that gets us to our next stage so um + + align:start position:0% +that gets us to our next stage so um + + + align:start position:0% +that gets us to our next stage so um +we're talking like we're talking kind of + + align:start position:0% +we're talking like we're talking kind of + + + align:start position:0% +we're talking like we're talking kind of +I think we find ourselves talking a lot + + align:start position:0% +I think we find ourselves talking a lot + + + align:start position:0% +I think we find ourselves talking a lot +about the um the product that we're + + align:start position:0% +about the um the product that we're + + + align:start position:0% +about the um the product that we're +making it's just easier it's the thing + + align:start position:0% +making it's just easier it's the thing + + + align:start position:0% +making it's just easier it's the thing +it's that it's that hard evident like + + align:start position:0% +it's that it's that hard evident like + + + align:start position:0% +it's that it's that hard evident like +that hard thing you can see like it's + + align:start position:0% +that hard thing you can see like it's + + + align:start position:0% +that hard thing you can see like it's +being made it's being done um it's we + + align:start position:0% +being made it's being done um it's we + + + align:start position:0% +being made it's being done um it's we +can play it it means we're probably + + align:start position:0% +can play it it means we're probably + + + align:start position:0% +can play it it means we're probably +doing something right um but it's still + + align:start position:0% +doing something right um but it's still + + + align:start position:0% +doing something right um but it's still +very difficult still to talk about the + + align:start position:0% +very difficult still to talk about the + + + align:start position:0% +very difficult still to talk about the +people although I saw being talking + + align:start position:0% +people although I saw being talking + + + align:start position:0% +people although I saw being talking +about the people a little bit here + + align:start position:0% +about the people a little bit here + + + align:start position:0% +about the people a little bit here +especially with accountability um and in + + align:start position:0% +especially with accountability um and in + + + align:start position:0% +especially with accountability um and in +this one was good cool + + align:start position:0% +this one was good cool + + + align:start position:0% +this one was good cool +um so that that g brings me to the next + + align:start position:0% +um so that that g brings me to the next + + + align:start position:0% +um so that that g brings me to the next +topic teams are composed of individuals + + align:start position:0% +topic teams are composed of individuals + + + align:start position:0% +topic teams are composed of individuals +and each person on your team is going to + + align:start position:0% +and each person on your team is going to + + + align:start position:0% +and each person on your team is going to +have a lot of different factors + + align:start position:0% +have a lot of different factors + + + align:start position:0% +have a lot of different factors +affecting what they do how they do it + + align:start position:0% +affecting what they do how they do it + + + align:start position:0% +affecting what they do how they do it +when they do it um I can't give you the + + align:start position:0% +when they do it um I can't give you the + + + align:start position:0% +when they do it um I can't give you the +magic formula to to get them motivated U + + align:start position:0% +magic formula to to get them motivated U + + + align:start position:0% +magic formula to to get them motivated U +what I can do is show you some of the + + align:start position:0% +what I can do is show you some of the + + + align:start position:0% +what I can do is show you some of the +different ways that you can then try to + + align:start position:0% +different ways that you can then try to + + + align:start position:0% +different ways that you can then try to +to to either understand the people + + align:start position:0% +to to either understand the people + + + align:start position:0% +to to either understand the people +you're with understand the people on + + align:start position:0% +you're with understand the people on + + + align:start position:0% +you're with understand the people on +your team or talk or find things to talk + + align:start position:0% +your team or talk or find things to talk + + + align:start position:0% +your team or talk or find things to talk +to them about you might notice a number + + align:start position:0% +to them about you might notice a number + + + align:start position:0% +to them about you might notice a number +of these things so to get someone who's + + align:start position:0% +of these things so to get someone who's + + + align:start position:0% +of these things so to get someone who's +motivated someone who's going to be able + + align:start position:0% +motivated someone who's going to be able + + + align:start position:0% +motivated someone who's going to be able +to participate um think about all these + + align:start position:0% +to participate um think about all these + + + align:start position:0% +to participate um think about all these +things think about personal + + align:start position:0% +things think about personal + + + align:start position:0% +things think about personal +development um so you were in a class + + align:start position:0% +development um so you were in a class + + + align:start position:0% +development um so you were in a class +you were here hopefully because you want + + align:start position:0% +you were here hopefully because you want + + + align:start position:0% +you were here hopefully because you want +to learn um you want to learn a new + + align:start position:0% +to learn um you want to learn a new + + + align:start position:0% +to learn um you want to learn a new +skill you want to try a new skill + + align:start position:0% +skill you want to try a new skill + + + align:start position:0% +skill you want to try a new skill +everyone wants to learn a new skill + + align:start position:0% +everyone wants to learn a new skill + + + align:start position:0% +everyone wants to learn a new skill +there might be a skill that they want to + + align:start position:0% +there might be a skill that they want to + + + align:start position:0% +there might be a skill that they want to +work on on your team and I think we've + + align:start position:0% +work on on your team and I think we've + + + align:start position:0% +work on on your team and I think we've +talked about that in the past when we're + + align:start position:0% +talked about that in the past when we're + + + align:start position:0% +talked about that in the past when we're +talking about the vision statement and + + align:start position:0% +talking about the vision statement and + + + align:start position:0% +talking about the vision statement and +people putting down why they're involved + + align:start position:0% +people putting down why they're involved + + + align:start position:0% +people putting down why they're involved +on the team and why they're involved on + + align:start position:0% +on the team and why they're involved on + + + align:start position:0% +on the team and why they're involved on +this project so being aware of that and + + align:start position:0% +this project so being aware of that and + + + align:start position:0% +this project so being aware of that and +constantly coming back to that for each + + align:start position:0% +constantly coming back to that for each + + + align:start position:0% +constantly coming back to that for each +person especially if you if you have + + align:start position:0% +person especially if you if you have + + + align:start position:0% +person especially if you if you have +someone on your team who's who is just + + align:start position:0% +someone on your team who's who is just + + + align:start position:0% +someone on your team who's who is just +not participating and you need to figure + + align:start position:0% +not participating and you need to figure + + + align:start position:0% +not participating and you need to figure +out um how to engage them think about + + align:start position:0% +out um how to engage them think about + + + align:start position:0% +out um how to engage them think about +the skills that they want to bring to + + align:start position:0% +the skills that they want to bring to + + + align:start position:0% +the skills that they want to bring to +the table the skills are trying to + + align:start position:0% +the table the skills are trying to + + + align:start position:0% +the table the skills are trying to +practice uh when it comes to motivation + + align:start position:0% +practice uh when it comes to motivation + + + align:start position:0% +practice uh when it comes to motivation +um it largely comes down to Intrinsic or + + align:start position:0% +um it largely comes down to Intrinsic or + + + align:start position:0% +um it largely comes down to Intrinsic or +extrinsic on the the the externs it + + align:start position:0% +extrinsic on the the the externs it + + + align:start position:0% +extrinsic on the the the externs it +might be the grade that they're going to + + align:start position:0% +might be the grade that they're going to + + + align:start position:0% +might be the grade that they're going to +get um but it's really difficult to um + + align:start position:0% +get um but it's really difficult to um + + + align:start position:0% +get um but it's really difficult to um +to really hone in on that because the + + align:start position:0% +to really hone in on that because the + + + align:start position:0% +to really hone in on that because the +grades shared between your group so that + + align:start position:0% +grades shared between your group so that + + + align:start position:0% +grades shared between your group so that +might be not be the place to look at um + + align:start position:0% +might be not be the place to look at um + + + align:start position:0% +might be not be the place to look at um +try to take a look at the intrinsic + + align:start position:0% +try to take a look at the intrinsic + + + align:start position:0% +try to take a look at the intrinsic +things what are the things that if they + + align:start position:0% +things what are the things that if they + + + align:start position:0% +things what are the things that if they +were enthusi en if they had enthusiasms + + align:start position:0% +were enthusi en if they had enthusiasms + + + align:start position:0% +were enthusi en if they had enthusiasms +about the project at some point um try + + align:start position:0% +about the project at some point um try + + + align:start position:0% +about the project at some point um try +to remember what that was um ask + + align:start position:0% +to remember what that was um ask + + + align:start position:0% +to remember what that was um ask +somebody else on your team what what + + align:start position:0% +somebody else on your team what what + + + align:start position:0% +somebody else on your team what what +that might have been see if you can + + align:start position:0% +that might have been see if you can + + + align:start position:0% +that might have been see if you can +bring those that enthusiasm back into + + align:start position:0% +bring those that enthusiasm back into + + + align:start position:0% +bring those that enthusiasm back into +the project um or selfworth and there's + + align:start position:0% +the project um or selfworth and there's + + + align:start position:0% +the project um or selfworth and there's +been some research that shows that the + + align:start position:0% +been some research that shows that the + + + align:start position:0% +been some research that shows that the +reason why people work well on teams and + + align:start position:0% +reason why people work well on teams and + + + align:start position:0% +reason why people work well on teams and +the reason why we want to work on teams + + align:start position:0% +the reason why we want to work on teams + + + align:start position:0% +the reason why we want to work on teams +is because it brings self it brings us + + align:start position:0% +is because it brings self it brings us + + + align:start position:0% +is because it brings self it brings us +selfworth um there is and in particular + + align:start position:0% +selfworth um there is and in particular + + + align:start position:0% +selfworth um there is and in particular +some self-awareness that can happen um + + align:start position:0% +some self-awareness that can happen um + + + align:start position:0% +some self-awareness that can happen um +by being on a team and getting um and it + + align:start position:0% +by being on a team and getting um and it + + + align:start position:0% +by being on a team and getting um and it +actually kind of links a little bit to + + align:start position:0% +actually kind of links a little bit to + + + align:start position:0% +actually kind of links a little bit to +to extrinsic rewards by getting rewarded + + align:start position:0% +to extrinsic rewards by getting rewarded + + + align:start position:0% +to extrinsic rewards by getting rewarded +getting feedback um on my performance is + + align:start position:0% +getting feedback um on my performance is + + + align:start position:0% +getting feedback um on my performance is +going to help me do better um + + align:start position:0% +going to help me do better um + + + align:start position:0% +going to help me do better um +empowerment um giving ownership so raise + + align:start position:0% +empowerment um giving ownership so raise + + + align:start position:0% +empowerment um giving ownership so raise +your hand if your team uses assigning + + align:start position:0% +your hand if your team uses assigning + + + align:start position:0% +your hand if your team uses assigning +tasks or taking tasks so assigning tasks + + align:start position:0% +tasks or taking tasks so assigning tasks + + + align:start position:0% +tasks or taking tasks so assigning tasks +raise your hand if your team assigns + + align:start position:0% +raise your hand if your team assigns + + + align:start position:0% +raise your hand if your team assigns +tasks to individuals that team kind of + + align:start position:0% +tasks to individuals that team kind of + + + align:start position:0% +tasks to individuals that team kind of +yeah you assign so there's one person on + + align:start position:0% +yeah you assign so there's one person on + + + align:start position:0% +yeah you assign so there's one person on +your team that says you are going to do + + align:start position:0% +your team that says you are going to do + + + align:start position:0% +your team that says you are going to do +this all right has anybody tried + + align:start position:0% +this all right has anybody tried + + + align:start position:0% +this all right has anybody tried +ownership where someone takes a task + + align:start position:0% +ownership where someone takes a task + + + align:start position:0% +ownership where someone takes a task +from a set of tasks that are + + align:start position:0% +from a set of tasks that are + + + align:start position:0% +from a set of tasks that are +available little little + + align:start position:0% +available little little + + + align:start position:0% +available little little +when does that work when does ownership + + align:start position:0% + + + + align:start position:0% + +work what's that people interested so + + align:start position:0% +work what's that people interested so + + + align:start position:0% +work what's that people interested so +there's there's some there's some of + + align:start position:0% +there's there's some there's some of + + + align:start position:0% +there's there's some there's some of +those other things that there's some + + align:start position:0% +those other things that there's some + + + align:start position:0% +those other things that there's some +enthusiasms over over it yeah it's + + align:start position:0% +enthusiasms over over it yeah it's + + + align:start position:0% +enthusiasms over over it yeah it's +usually like a while before the + + align:start position:0% +usually like a while before the + + + align:start position:0% +usually like a while before the +deadine Okay cool so yeah yeah you can + + align:start position:0% +deadine Okay cool so yeah yeah you can + + + align:start position:0% +deadine Okay cool so yeah yeah you can +problem you say's do this andbody + + align:start position:0% +problem you say's do this andbody + + + align:start position:0% +problem you say's do this andbody +volunteers my experience has been kind + + align:start position:0% +volunteers my experience has been kind + + + align:start position:0% +volunteers my experience has been kind +of it's good if people volunteer for + + align:start position:0% +of it's good if people volunteer for + + + align:start position:0% +of it's good if people volunteer for +tasks enas about but then nobody will to + + align:start position:0% +tasks enas about but then nobody will to + + + align:start position:0% +tasks enas about but then nobody will to +do something that needs to + + align:start position:0% +do something that needs to + + + align:start position:0% +do something that needs to +beone this absolutely H okay so where + + align:start position:0% +beone this absolutely H okay so where + + + align:start position:0% +beone this absolutely H okay so where +does yeah go + + align:start position:0% + + + + align:start position:0% + +ahead absolutely so there's + + align:start position:0% + + + + align:start position:0% + +some I think something that's kind of at + + align:start position:0% +some I think something that's kind of at + + + align:start position:0% +some I think something that's kind of at +the beginning + + align:start position:0% +the beginning + + + align:start position:0% +the beginning +and then like Tas + + align:start position:0% + + + + align:start position:0% + +are okay so so at the beginning um + + align:start position:0% +are okay so so at the beginning um + + + align:start position:0% +are okay so so at the beginning um +everybody takes on tasks and at the end + + align:start position:0% +everybody takes on tasks and at the end + + + align:start position:0% +everybody takes on tasks and at the end +when you have the leftovers um they get + + align:start position:0% +when you have the leftovers um they get + + + align:start position:0% +when you have the leftovers um they get +assigned yeah Matt one of the biggest + + align:start position:0% +assigned yeah Matt one of the biggest + + + align:start position:0% +assigned yeah Matt one of the biggest +problems I've seen this is that + + align:start position:0% +problems I've seen this is that + + + align:start position:0% +problems I've seen this is that +you're espe this is easy we have a lot + + align:start position:0% +you're espe this is easy we have a lot + + + align:start position:0% +you're espe this is easy we have a lot +of other + + align:start position:0% + + + + align:start position:0% + +then so it might not you yeah so you + + align:start position:0% +then so it might not you yeah so you + + + align:start position:0% +then so it might not you yeah so you +might not actually have ownership it + + align:start position:0% +might not actually have ownership it + + + align:start position:0% +might not actually have ownership it +might look like you had ownership there + + align:start position:0% +might look like you had ownership there + + + align:start position:0% +might look like you had ownership there +is the evidence of ownership in that + + align:start position:0% +is the evidence of ownership in that + + + align:start position:0% +is the evidence of ownership in that +someone said okay I'll take that task + + align:start position:0% +someone said okay I'll take that task + + + align:start position:0% +someone said okay I'll take that task +but there's no there's no follow-through + + align:start position:0% +but there's no there's no follow-through + + + align:start position:0% +but there's no there's no follow-through +there's no commitment and that gets to + + align:start position:0% +there's no commitment and that gets to + + + align:start position:0% +there's no commitment and that gets to +the next one commitment um the best way + + align:start position:0% +the next one commitment um the best way + + + align:start position:0% +the next one commitment um the best way +to have commitment on your team is for + + align:start position:0% +to have commitment on your team is for + + + align:start position:0% +to have commitment on your team is for +one person to be committed to express + + align:start position:0% +one person to be committed to express + + + align:start position:0% +one person to be committed to express +that commitment to express that loyalty + + align:start position:0% +that commitment to express that loyalty + + + align:start position:0% +that commitment to express that loyalty +for everyone else to see that loyalty + + align:start position:0% +for everyone else to see that loyalty + + + align:start position:0% +for everyone else to see that loyalty +and see that commitment and then + + align:start position:0% +and see that commitment and then + + + align:start position:0% +and see that commitment and then +hopefully they pick up the ball and + + align:start position:0% +hopefully they pick up the ball and + + + align:start position:0% +hopefully they pick up the ball and +they're like okay I'm going to be + + align:start position:0% +they're like okay I'm going to be + + + align:start position:0% +they're like okay I'm going to be +committed to if that second person + + align:start position:0% +committed to if that second person + + + align:start position:0% +committed to if that second person +doesn't do that pick it up then the + + align:start position:0% +doesn't do that pick it up then the + + + align:start position:0% +doesn't do that pick it up then the +chain it doesn't travel through the + + align:start position:0% +chain it doesn't travel through the + + + align:start position:0% +chain it doesn't travel through the +chain it just doesn't happen even though + + align:start position:0% +chain it just doesn't happen even though + + + align:start position:0% +chain it just doesn't happen even though +that one person went out of the way to + + align:start position:0% +that one person went out of the way to + + + align:start position:0% +that one person went out of the way to +to show that kind of sacrifice it just + + align:start position:0% +to show that kind of sacrifice it just + + + align:start position:0% +to show that kind of sacrifice it just +didn't get picked up um so maybe think + + align:start position:0% +didn't get picked up um so maybe think + + + align:start position:0% +didn't get picked up um so maybe think +about is that do do you see that chain + + align:start position:0% +about is that do do you see that chain + + + align:start position:0% +about is that do do you see that chain +happening on your on your teams do you + + align:start position:0% +happening on your on your teams do you + + + align:start position:0% +happening on your on your teams do you +see it breaking can you identify where + + align:start position:0% +see it breaking can you identify where + + + align:start position:0% +see it breaking can you identify where +that breaking point is and can you think + + align:start position:0% +that breaking point is and can you think + + + align:start position:0% +that breaking point is and can you think +about ways to to to fix + + align:start position:0% +about ways to to to fix + + + align:start position:0% +about ways to to to fix +that um trust is a big one um how many + + align:start position:0% +that um trust is a big one um how many + + + align:start position:0% +that um trust is a big one um how many +so raise your hands if you have worked + + align:start position:0% +so raise your hands if you have worked + + + align:start position:0% +so raise your hands if you have worked +with the majority of the people on your + + align:start position:0% +with the majority of the people on your + + + align:start position:0% +with the majority of the people on your +team before in some fashion this class + + align:start position:0% +team before in some fashion this class + + + align:start position:0% +team before in some fashion this class +or other classes you you feel like you + + align:start position:0% +or other classes you you feel like you + + + align:start position:0% +or other classes you you feel like you +know your teammates like raise your + + align:start position:0% +know your teammates like raise your + + + align:start position:0% +know your teammates like raise your +hands if you feel like you really know + + align:start position:0% +hands if you feel like you really know + + + align:start position:0% +hands if you feel like you really know +your teammates you've worked with them + + align:start position:0% +your teammates you've worked with them + + + align:start position:0% +your teammates you've worked with them +before hi if you really think so so one + + align:start position:0% +before hi if you really think so so one + + + align:start position:0% +before hi if you really think so so one +two maybe one two + + align:start position:0% +two maybe one two + + + align:start position:0% +two maybe one two +three so think about how well you know + + align:start position:0% +three so think about how well you know + + + align:start position:0% +three so think about how well you know +each other think about ways you can + + align:start position:0% +each other think about ways you can + + + align:start position:0% +each other think about ways you can +figure out how you can know each other + + align:start position:0% +figure out how you can know each other + + + align:start position:0% +figure out how you can know each other +better um social + + align:start position:0% +better um social + + + align:start position:0% +better um social +interactions going up to coffee going up + + align:start position:0% +interactions going up to coffee going up + + + align:start position:0% +interactions going up to coffee going up +for lunch things like that is there + + align:start position:0% +for lunch things like that is there + + + align:start position:0% +for lunch things like that is there +something that you can do that will help + + align:start position:0% +something that you can do that will help + + + align:start position:0% +something that you can do that will help +that kind of that kind of thing H happen + + align:start position:0% +that kind of that kind of thing H happen + + + align:start position:0% +that kind of that kind of thing H happen +and then here's the big one this is the + + align:start position:0% +and then here's the big one this is the + + + align:start position:0% +and then here's the big one this is the +mit1 stress and stress tends to be the + + align:start position:0% +mit1 stress and stress tends to be the + + + align:start position:0% +mit1 stress and stress tends to be the +the negative it can be positive in that + + align:start position:0% +the negative it can be positive in that + + + align:start position:0% +the negative it can be positive in that +it's the end of the project and it's due + + align:start position:0% +it's the end of the project and it's due + + + align:start position:0% +it's the end of the project and it's due +and you just need to get things done and + + align:start position:0% +and you just need to get things done and + + + align:start position:0% +and you just need to get things done and +that can be that can lead to crunch but + + align:start position:0% +that can be that can lead to crunch but + + + align:start position:0% +that can be that can lead to crunch but +then there's also the huge negative + + align:start position:0% +then there's also the huge negative + + + align:start position:0% +then there's also the huge negative +aspect of stress and it's a very that's + + align:start position:0% +aspect of stress and it's a very that's + + + align:start position:0% +aspect of stress and it's a very that's +very much an external factor for the + + align:start position:0% +very much an external factor for the + + + align:start position:0% +very much an external factor for the +most part um it could be an internal + + align:start position:0% +most part um it could be an internal + + + align:start position:0% +most part um it could be an internal +Factor if if stress isn't if there's + + align:start position:0% +Factor if if stress isn't if there's + + + align:start position:0% +Factor if if stress isn't if there's +some stress being caused by internal um + + align:start position:0% +some stress being caused by internal um + + + align:start position:0% +some stress being caused by internal um +things going on with your team it's + + align:start position:0% +things going on with your team it's + + + align:start position:0% +things going on with your team it's +likely related to one of the ones above + + align:start position:0% + + + + align:start position:0% + +it um so so one way to think about um + + align:start position:0% +it um so so one way to think about um + + + align:start position:0% +it um so so one way to think about um +these these three uh one two three seven + + align:start position:0% +these these three uh one two three seven + + + align:start position:0% +these these three uh one two three seven +things um you can think of them as in + + align:start position:0% +things um you can think of them as in + + + align:start position:0% +things um you can think of them as in +terms of the desire ability to learn new + + align:start position:0% +terms of the desire ability to learn new + + + align:start position:0% +terms of the desire ability to learn new +skills or the desire ability to take on + + align:start position:0% +skills or the desire ability to take on + + + align:start position:0% +skills or the desire ability to take on +a task um so if you're trying to come up + + align:start position:0% +a task um so if you're trying to come up + + + align:start position:0% +a task um so if you're trying to come up +with strategies within your team on how + + align:start position:0% +with strategies within your team on how + + + align:start position:0% +with strategies within your team on how +to how to solve some of these problems + + align:start position:0% +to how to solve some of these problems + + + align:start position:0% +to how to solve some of these problems +think of it in those two + + align:start position:0% + + + + align:start position:0% + +terms all right so how do distributed + + align:start position:0% +terms all right so how do distributed + + + align:start position:0% +terms all right so how do distributed +teams perform um so what do I mean by + + align:start position:0% +teams perform um so what do I mean by + + + align:start position:0% +teams perform um so what do I mean by +distributed what is a distributed + + align:start position:0% + + + + align:start position:0% + +team + + align:start position:0% + + + + align:start position:0% + +yeah yeah or just everyone's all over + + align:start position:0% +yeah yeah or just everyone's all over + + + align:start position:0% +yeah yeah or just everyone's all over +the place it could mean that you are in + + align:start position:0% +the place it could mean that you are in + + + align:start position:0% +the place it could mean that you are in +Singapore and someone else is in Ohio um + + align:start position:0% +Singapore and someone else is in Ohio um + + + align:start position:0% +Singapore and someone else is in Ohio um +you could be separated by time zones by + + align:start position:0% +you could be separated by time zones by + + + align:start position:0% +you could be separated by time zones by +oceans um by and really I think that + + align:start position:0% +oceans um by and really I think that + + + align:start position:0% +oceans um by and really I think that +might be East Campus and McGregor maybe + + align:start position:0% +might be East Campus and McGregor maybe + + + align:start position:0% +might be East Campus and McGregor maybe +um it could just be through distance it + + align:start position:0% +um it could just be through distance it + + + align:start position:0% +um it could just be through distance it +could be through your schools it could + + align:start position:0% +could be through your schools it could + + + align:start position:0% +could be through your schools it could +be through your departments your Majors + + align:start position:0% +be through your departments your Majors + + + align:start position:0% +be through your departments your Majors +whatnot um there's some kind of + + align:start position:0% +whatnot um there's some kind of + + + align:start position:0% +whatnot um there's some kind of +boundaries going on between people um in + + align:start position:0% +boundaries going on between people um in + + + align:start position:0% +boundaries going on between people um in +this case it's it's largely time um it's + + align:start position:0% +this case it's it's largely time um it's + + + align:start position:0% +this case it's it's largely time um it's +basically some people can work during + + align:start position:0% +basically some people can work during + + + align:start position:0% +basically some people can work during +some hours some people can't can't work + + align:start position:0% +some hours some people can't can't work + + + align:start position:0% +some hours some people can't can't work +during those hour those other hours so + + align:start position:0% +during those hour those other hours so + + + align:start position:0% +during those hour those other hours so +what have you done so far to to to fix + + align:start position:0% +what have you done so far to to to fix + + + align:start position:0% +what have you done so far to to to fix +that you think back on some of the + + align:start position:0% +that you think back on some of the + + + align:start position:0% +that you think back on some of the +postmortem you've given us what are some + + align:start position:0% +postmortem you've given us what are some + + + align:start position:0% +postmortem you've given us what are some +of the strategies you've already used + + align:start position:0% +of the strategies you've already used + + + align:start position:0% +of the strategies you've already used +and seen used to to figure out how to + + align:start position:0% +and seen used to to figure out how to + + + align:start position:0% +and seen used to to figure out how to +work in across different time time + + align:start position:0% +work in across different time time + + + align:start position:0% +work in across different time time +periods + + align:start position:0% + + + + align:start position:0% + +yeah what's it + + align:start position:0% +yeah what's it + + + align:start position:0% +yeah what's it +called it's like + + align:start position:0% +called it's like + + + align:start position:0% +called it's like +what what's that it's group instant M + + align:start position:0% +what what's that it's group instant M + + + align:start position:0% +what what's that it's group instant M +yay and it keeps of + + align:start position:0% + + + + align:start position:0% + +allas cool anybody else using a group I + + align:start position:0% +allas cool anybody else using a group I + + + align:start position:0% +allas cool anybody else using a group I +or an IRC chat + + align:start position:0% + + + + align:start position:0% + +yeah + + align:start position:0% + + + + align:start position:0% + +cool cool okay it's great when it have + + align:start position:0% +cool cool okay it's great when it have + + + align:start position:0% +cool cool okay it's great when it have +when it can hook up to things and it + + align:start position:0% +when it can hook up to things and it + + + align:start position:0% +when it can hook up to things and it +works with your workflow it's also just + + align:start position:0% +works with your workflow it's also just + + + align:start position:0% +works with your workflow it's also just +great to have just period if you don't + + align:start position:0% +great to have just period if you don't + + + align:start position:0% +great to have just period if you don't +use any of those maybe think about Skype + + align:start position:0% +use any of those maybe think about Skype + + + align:start position:0% +use any of those maybe think about Skype +any other things people use + + align:start position:0% +any other things people use + + + align:start position:0% +any other things people use +yeah in my experience + + align:start position:0% +yeah in my experience + + + align:start position:0% +yeah in my experience +like let's say we walking on something + + align:start position:0% +like let's say we walking on something + + + align:start position:0% +like let's say we walking on something +and all of at that point be good to like + + align:start position:0% +and all of at that point be good to like + + + align:start position:0% +and all of at that point be good to like +keep the whole team informed about your + + align:start position:0% +keep the whole team informed about your + + + align:start position:0% +keep the whole team informed about your +progress what Isen on + + align:start position:0% + + + + align:start position:0% + +your so + + align:start position:0% + + + + align:start position:0% + +reporting I remember some people had + + align:start position:0% +reporting I remember some people had + + + align:start position:0% +reporting I remember some people had +issues with email on previous teams is + + align:start position:0% +issues with email on previous teams is + + + align:start position:0% +issues with email on previous teams is +anybody still using email as a primary + + align:start position:0% +anybody still using email as a primary + + + align:start position:0% +anybody still using email as a primary +means of communication on your + + align:start position:0% +means of communication on your + + + align:start position:0% +means of communication on your +team how's it working for you all so far + + align:start position:0% +team how's it working for you all so far + + + align:start position:0% +team how's it working for you all so far +has it got to the + + align:start position:0% + + + + align:start position:0% + +yeah yep um are those emails going to be + + align:start position:0% +yeah yep um are those emails going to be + + + align:start position:0% +yeah yep um are those emails going to be +archived and viewable by everyone at a + + align:start position:0% +archived and viewable by everyone at a + + + align:start position:0% +archived and viewable by everyone at a +later date be a good idea yeah + + align:start position:0% +later date be a good idea yeah + + + align:start position:0% +later date be a good idea yeah +um and I think that's why we tend to to + + align:start position:0% +um and I think that's why we tend to to + + + align:start position:0% +um and I think that's why we tend to to +think about um group IMS and + + align:start position:0% +think about um group IMS and + + + align:start position:0% +think about um group IMS and +particularly um Philip likes IRC for + + align:start position:0% +particularly um Philip likes IRC for + + + align:start position:0% +particularly um Philip likes IRC for +that very reason certain IRC servers we + + align:start position:0% +that very reason certain IRC servers we + + + align:start position:0% +that very reason certain IRC servers we +we'll keep an archive for you um other + + align:start position:0% +we'll keep an archive for you um other + + + align:start position:0% +we'll keep an archive for you um other +kinds of groupware we'll do that too but + + align:start position:0% +kinds of groupware we'll do that too but + + + align:start position:0% +kinds of groupware we'll do that too but +they tend to be pricey um um is anybody + + align:start position:0% +they tend to be pricey um um is anybody + + + align:start position:0% +they tend to be pricey um um is anybody +still using has anybody started using + + align:start position:0% +still using has anybody started using + + + align:start position:0% +still using has anybody started using +Trello on your teams + + align:start position:0% +Trello on your teams + + + align:start position:0% +Trello on your teams +yet yeah are you using it as a + + align:start position:0% +yet yeah are you using it as a + + + align:start position:0% +yet yeah are you using it as a +communication method or as a recording + + align:start position:0% +communication method or as a recording + + + align:start position:0% +communication method or as a recording +of + + align:start position:0% +of + + + align:start position:0% +of +things okay anybody using that as a + + align:start position:0% +things okay anybody using that as a + + + align:start position:0% +things okay anybody using that as a +communication method at all trying that + + align:start position:0% +communication method at all trying that + + + align:start position:0% +communication method at all trying that +out okay because I think it do it can do + + align:start position:0% +out okay because I think it do it can do + + + align:start position:0% +out okay because I think it do it can do +email notifications and things like that + + align:start position:0% +email notifications and things like that + + + align:start position:0% +email notifications and things like that +when things change assigning members to + + align:start position:0% +when things change assigning members to + + + align:start position:0% +when things change assigning members to +tasks stuff like + + align:start position:0% +tasks stuff like + + + align:start position:0% +tasks stuff like +that + + align:start position:0% +that + + + align:start position:0% +that +cool all right so again we got talking + + align:start position:0% +cool all right so again we got talking + + + align:start position:0% +cool all right so again we got talking +into + + align:start position:0% +into + + + align:start position:0% +into +tools um what other things can we do so + + align:start position:0% +tools um what other things can we do so + + + align:start position:0% +tools um what other things can we do so +um another another paper that it's going + + align:start position:0% +um another another paper that it's going + + + align:start position:0% +um another another paper that it's going +to be on Stellar if you want to look at + + align:start position:0% +to be on Stellar if you want to look at + + + align:start position:0% +to be on Stellar if you want to look at +it was basically a survey of distributed + + align:start position:0% +it was basically a survey of distributed + + + align:start position:0% +it was basically a survey of distributed +teams using angel processes and giving + + align:start position:0% +teams using angel processes and giving + + + align:start position:0% +teams using angel processes and giving +up some best practices of what worked + + align:start position:0% +up some best practices of what worked + + + align:start position:0% +up some best practices of what worked +best for them and I was nice and I'm + + align:start position:0% +best for them and I was nice and I'm + + + align:start position:0% +best for them and I was nice and I'm +just giving you the uh summary of that + + align:start position:0% +just giving you the uh summary of that + + + align:start position:0% +just giving you the uh summary of that +um so one thing they noticed is having a + + align:start position:0% +um so one thing they noticed is having a + + + align:start position:0% +um so one thing they noticed is having a +one team mindset was the thing that got + + align:start position:0% +one team mindset was the thing that got + + + align:start position:0% +one team mindset was the thing that got +them through um working together as a + + align:start position:0% +them through um working together as a + + + align:start position:0% +them through um working together as a +group um what do we mean by one team + + align:start position:0% +group um what do we mean by one team + + + align:start position:0% +group um what do we mean by one team +that the the group identifies well first + + align:start position:0% +that the the group identifies well first + + + align:start position:0% +that the the group identifies well first +it identifies as a team like what we + + align:start position:0% +it identifies as a team like what we + + + align:start position:0% +it identifies as a team like what we +talked about before they all have a of a + + align:start position:0% +talked about before they all have a of a + + + align:start position:0% +talked about before they all have a of a +a goal that they're going towards they + + align:start position:0% +a goal that they're going towards they + + + align:start position:0% +a goal that they're going towards they +all identify as going towards that goal + + align:start position:0% +all identify as going towards that goal + + + align:start position:0% +all identify as going towards that goal +um they don't identify as as just a as + + align:start position:0% +um they don't identify as as just a as + + + align:start position:0% +um they don't identify as as just a as +an individual + + align:start position:0% +an individual + + + align:start position:0% +an individual +group but that's a that's actually a + + align:start position:0% +group but that's a that's actually a + + + align:start position:0% +group but that's a that's actually a +major part of their identity um and for + + align:start position:0% +major part of their identity um and for + + + align:start position:0% +major part of their identity um and for +them it's because that's their 40h hour + + align:start position:0% +them it's because that's their 40h hour + + + align:start position:0% +them it's because that's their 40h hour +80 hour 12 hour work days uh or work + + align:start position:0% +80 hour 12 hour work days uh or work + + + align:start position:0% +80 hour 12 hour work days uh or work +weeks um something I think you you going + + align:start position:0% +weeks um something I think you you going + + + align:start position:0% +weeks um something I think you you going +to have issue with because you're only + + align:start position:0% +to have issue with because you're only + + + align:start position:0% +to have issue with because you're only +because you're working smaller periods + + align:start position:0% +because you're working smaller periods + + + align:start position:0% +because you're working smaller periods +of time um but what they're able to do + + align:start position:0% +of time um but what they're able to do + + + align:start position:0% +of time um but what they're able to do +the way they're able to do that is + + align:start position:0% +the way they're able to do that is + + + align:start position:0% +the way they're able to do that is +they've got these frequent team + + align:start position:0% +they've got these frequent team + + + align:start position:0% +they've got these frequent team +interactions and actually when they're + + align:start position:0% +interactions and actually when they're + + + align:start position:0% +interactions and actually when they're +working for a long period of time + + align:start position:0% +working for a long period of time + + + align:start position:0% +working for a long period of time +they're still there are people who are + + align:start position:0% +they're still there are people who are + + + align:start position:0% +they're still there are people who are +working on their own in their home or + + align:start position:0% +working on their own in their home or + + + align:start position:0% +working on their own in their home or +their home office with another team + + align:start position:0% +their home office with another team + + + align:start position:0% +their home office with another team +that's that's very far away and yet + + align:start position:0% +that's that's very far away and yet + + + align:start position:0% +that's that's very far away and yet +these these teams still do a daily + + align:start position:0% +these these teams still do a daily + + + align:start position:0% +these these teams still do a daily +standup does anybody here do a daily + + align:start position:0% +standup does anybody here do a daily + + + align:start position:0% +standup does anybody here do a daily +standup on their on their teams right + + align:start position:0% +standup on their on their teams right + + + align:start position:0% +standup on their on their teams right +now so what they're doing is they're + + align:start position:0% +now so what they're doing is they're + + + align:start position:0% +now so what they're doing is they're +going on video they're talking to each + + align:start position:0% +going on video they're talking to each + + + align:start position:0% +going on video they're talking to each +other for a very short period of time + + align:start position:0% +other for a very short period of time + + + align:start position:0% +other for a very short period of time +about what they've done what they're + + align:start position:0% +about what they've done what they're + + + align:start position:0% +about what they've done what they're +going to do what's in their way um the + + align:start position:0% +going to do what's in their way um the + + + align:start position:0% +going to do what's in their way um the +cool thing with daily standups and why + + align:start position:0% +cool thing with daily standups and why + + + align:start position:0% +cool thing with daily standups and why +they think this works for them there's + + align:start position:0% +they think this works for them there's + + + align:start position:0% +they think this works for them there's +it goes back to those those um seven + + align:start position:0% +it goes back to those those um seven + + + align:start position:0% +it goes back to those those um seven +items I listed about how do you get + + align:start position:0% +items I listed about how do you get + + + align:start position:0% +items I listed about how do you get +people engaged on a team it shows + + align:start position:0% +people engaged on a team it shows + + + align:start position:0% +people engaged on a team it shows +commitment um the fact that there are + + align:start position:0% +commitment um the fact that there are + + + align:start position:0% +commitment um the fact that there are +some people that there are people who + + align:start position:0% +some people that there are people who + + + align:start position:0% +some people that there are people who +are showing up to to meetings that there + + align:start position:0% +are showing up to to meetings that there + + + align:start position:0% +are showing up to to meetings that there +is some kind of personal sacrifice some + + align:start position:0% +is some kind of personal sacrifice some + + + align:start position:0% +is some kind of personal sacrifice some +people are meeting at a very strange + + align:start position:0% +people are meeting at a very strange + + + align:start position:0% +people are meeting at a very strange +hour of the day that they're not + + align:start position:0% +hour of the day that they're not + + + align:start position:0% +hour of the day that they're not +normally going to meet um and they're + + align:start position:0% +normally going to meet um and they're + + + align:start position:0% +normally going to meet um and they're +doing that because of the team they're + + align:start position:0% +doing that because of the team they're + + + align:start position:0% +doing that because of the team they're +sacrificing something personal for the + + align:start position:0% +sacrificing something personal for the + + + align:start position:0% +sacrificing something personal for the +team everyone else on the team sees that + + align:start position:0% +team everyone else on the team sees that + + + align:start position:0% +team everyone else on the team sees that +they see that kind of commitment they + + align:start position:0% +they see that kind of commitment they + + + align:start position:0% +they see that kind of commitment they +feel they feel like they need to reflect + + align:start position:0% +feel they feel like they need to reflect + + + align:start position:0% +feel they feel like they need to reflect +that back themselves also trust and in + + align:start position:0% +that back themselves also trust and in + + + align:start position:0% +that back themselves also trust and in +this particular case it's the trust of + + align:start position:0% +this particular case it's the trust of + + + align:start position:0% +this particular case it's the trust of +not letting meetings take too long these + + align:start position:0% +not letting meetings take too long these + + + align:start position:0% +not letting meetings take too long these +daily standups really should only take + + align:start position:0% +daily standups really should only take + + + align:start position:0% +daily standups really should only take +10 minutes um an effective team can do + + align:start position:0% +10 minutes um an effective team can do + + + align:start position:0% +10 minutes um an effective team can do +it in five um an effective 10 person + + align:start position:0% +it in five um an effective 10 person + + + align:start position:0% +it in five um an effective 10 person +team 30 seconds each go everyone says + + align:start position:0% +team 30 seconds each go everyone says + + + align:start position:0% +team 30 seconds each go everyone says +what they've done everyone sees each + + align:start position:0% +what they've done everyone sees each + + + align:start position:0% +what they've done everyone sees each +other's faces the great thing about + + align:start position:0% +other's faces the great thing about + + + align:start position:0% +other's faces the great thing about +seeing each other's faces is you can see + + align:start position:0% +seeing each other's faces is you can see + + + align:start position:0% +seeing each other's faces is you can see +what stage of fear and anxiety they're + + align:start position:0% +what stage of fear and anxiety they're + + + align:start position:0% +what stage of fear and anxiety they're +in then you can then talk to them later + + align:start position:0% +in then you can then talk to them later + + + align:start position:0% +in then you can then talk to them later +and have some other personal + + align:start position:0% +and have some other personal + + + align:start position:0% +and have some other personal +interactions with + + align:start position:0% +interactions with + + + align:start position:0% +interactions with +them um other thing they do is they they + + align:start position:0% +them um other thing they do is they they + + + align:start position:0% +them um other thing they do is they they +do collocated work um they've got money + + align:start position:0% +do collocated work um they've got money + + + align:start position:0% +do collocated work um they've got money +sometimes so they're flying people back + + align:start position:0% +sometimes so they're flying people back + + + align:start position:0% +sometimes so they're flying people back +and forth um but again they're also + + align:start position:0% +and forth um but again they're also + + + align:start position:0% +and forth um but again they're also +doing collocated work by doing things + + align:start position:0% +doing collocated work by doing things + + + align:start position:0% +doing collocated work by doing things +using having Skype always on in the + + align:start position:0% +using having Skype always on in the + + + align:start position:0% +using having Skype always on in the +background while they're working + + align:start position:0% +background while they're working + + + align:start position:0% +background while they're working +together but they're not doing it the + + align:start position:0% +together but they're not doing it the + + + align:start position:0% +together but they're not doing it the +entire time they can't afford that so + + align:start position:0% +entire time they can't afford that so + + + align:start position:0% +entire time they can't afford that so +one thing you can do is to schedule your + + align:start position:0% +one thing you can do is to schedule your + + + align:start position:0% +one thing you can do is to schedule your +collocated time at the beginning of the + + align:start position:0% +collocated time at the beginning of the + + + align:start position:0% +collocated time at the beginning of the +project which I which is basically what + + align:start position:0% +project which I which is basically what + + + align:start position:0% +project which I which is basically what +we've been doing in class for the past + + align:start position:0% +we've been doing in class for the past + + + align:start position:0% +we've been doing in class for the past +few weeks at identifying important + + align:start position:0% +few weeks at identifying important + + + align:start position:0% +few weeks at identifying important +milestones and making sure you've + + align:start position:0% +milestones and making sure you've + + + align:start position:0% +milestones and making sure you've +scheduled a collocated period during + + align:start position:0% +scheduled a collocated period during + + + align:start position:0% +scheduled a collocated period during +that Milestone right before that + + align:start position:0% +that Milestone right before that + + + align:start position:0% +that Milestone right before that +Milestone is going to help you greatly + + align:start position:0% +Milestone is going to help you greatly + + + align:start position:0% +Milestone is going to help you greatly +doing instrict teams and doing video + + align:start position:0% + + + + align:start position:0% + +chat and here's a big one we haven't + + align:start position:0% +chat and here's a big one we haven't + + + align:start position:0% +chat and here's a big one we haven't +talked about in class so much um but I + + align:start position:0% +talked about in class so much um but I + + + align:start position:0% +talked about in class so much um but I +get the impression that some of you + + align:start position:0% +get the impression that some of you + + + align:start position:0% +get the impression that some of you +might be interested in this kind of + + align:start position:0% +might be interested in this kind of + + + align:start position:0% +might be interested in this kind of +thing um having coaches so we've already + + align:start position:0% +thing um having coaches so we've already + + + align:start position:0% +thing um having coaches so we've already +we've already seen some of the teams um + + align:start position:0% +we've already seen some of the teams um + + + align:start position:0% +we've already seen some of the teams um +have dedicated scrum master or producer + + align:start position:0% +have dedicated scrum master or producer + + + align:start position:0% +have dedicated scrum master or producer +think about having a dedicated coach so + + align:start position:0% +think about having a dedicated coach so + + + align:start position:0% +think about having a dedicated coach so +someone who's on your team who is there + + align:start position:0% +someone who's on your team who is there + + + align:start position:0% +someone who's on your team who is there +to cultivate team spirit um they're + + align:start position:0% +to cultivate team spirit um they're + + + align:start position:0% +to cultivate team spirit um they're +going to emphasize the importance of one + + align:start position:0% +going to emphasize the importance of one + + + align:start position:0% +going to emphasize the importance of one +team they could be your scrum master or + + align:start position:0% +team they could be your scrum master or + + + align:start position:0% +team they could be your scrum master or +producer but they don't actually should + + align:start position:0% +producer but they don't actually should + + + align:start position:0% +producer but they don't actually should +they they're not actually the same role + + align:start position:0% +they they're not actually the same role + + + align:start position:0% +they they're not actually the same role +the scrum Master the producer is + + align:start position:0% +the scrum Master the producer is + + + align:start position:0% +the scrum Master the producer is +measuring productivity they're measuring + + align:start position:0% +measuring productivity they're measuring + + + align:start position:0% +measuring productivity they're measuring +tasks um how will things get done um the + + align:start position:0% +tasks um how will things get done um the + + + align:start position:0% +tasks um how will things get done um the +coaches a very different they're looking + + align:start position:0% +coaches a very different they're looking + + + align:start position:0% +coaches a very different they're looking +at how people interact with each other + + align:start position:0% +at how people interact with each other + + + align:start position:0% +at how people interact with each other +how people talk to each other how people + + align:start position:0% +how people talk to each other how people + + + align:start position:0% +how people talk to each other how people +work with each other often times people + + align:start position:0% +work with each other often times people + + + align:start position:0% +work with each other often times people +who are naturally inclined to do one can + + align:start position:0% +who are naturally inclined to do one can + + + align:start position:0% +who are naturally inclined to do one can +be inclined to do the other but that's + + align:start position:0% +be inclined to do the other but that's + + + align:start position:0% +be inclined to do the other but that's +not always the case um so if you have + + align:start position:0% +not always the case um so if you have + + + align:start position:0% +not always the case um so if you have +someone on your team who is one of those + + align:start position:0% +someone on your team who is one of those + + + align:start position:0% +someone on your team who is one of those +extroverted outgoing or even introverted + + align:start position:0% +extroverted outgoing or even introverted + + + align:start position:0% +extroverted outgoing or even introverted +but really interested in what + + align:start position:0% +but really interested in what + + + align:start position:0% +but really interested in what +individuals do oneon-one and how + + align:start position:0% +individuals do oneon-one and how + + + align:start position:0% +individuals do oneon-one and how +individuals work um see if you can um + + align:start position:0% +individuals work um see if you can um + + + align:start position:0% +individuals work um see if you can um +incorporate some coaching strategies uh + + align:start position:0% +incorporate some coaching strategies uh + + + align:start position:0% +incorporate some coaching strategies uh +with with your teammates and again you + + align:start position:0% +with with your teammates and again you + + + align:start position:0% +with with your teammates and again you +can do one-on-one meetings um and we can + + align:start position:0% +can do one-on-one meetings um and we can + + + align:start position:0% +can do one-on-one meetings um and we can +talk about this in the future if you're + + align:start position:0% +talk about this in the future if you're + + + align:start position:0% +talk about this in the future if you're +interested in this kind of stuff we can + + align:start position:0% +interested in this kind of stuff we can + + + align:start position:0% +interested in this kind of stuff we can +we can unpack on this topic and talk + + align:start position:0% +we can unpack on this topic and talk + + + align:start position:0% +we can unpack on this topic and talk +about it further um but I highly + + align:start position:0% +about it further um but I highly + + + align:start position:0% +about it further um but I highly +recommend + + align:start position:0% +recommend + + + align:start position:0% +recommend +it all right so um I did mention + + align:start position:0% +it all right so um I did mention + + + align:start position:0% +it all right so um I did mention +meetings um you do have agile meetings + + align:start position:0% +meetings um you do have agile meetings + + + align:start position:0% +meetings um you do have agile meetings +these people have agile meetings um + + align:start position:0% +these people have agile meetings um + + + align:start position:0% +these people have agile meetings um +these are what they are hopefully you're + + align:start position:0% +these are what they are hopefully you're + + + align:start position:0% +these are what they are hopefully you're +doing + + align:start position:0% +doing + + + align:start position:0% +doing +so who has a formal Sprint process where + + align:start position:0% +so who has a formal Sprint process where + + + align:start position:0% +so who has a formal Sprint process where +you plan your Sprint before you start so + + align:start position:0% +you plan your Sprint before you start so + + + align:start position:0% +you plan your Sprint before you start so +you create a task you basically you + + align:start position:0% +you create a task you basically you + + + align:start position:0% +you create a task you basically you +create your Sprint task list at a at a + + align:start position:0% +create your Sprint task list at a at a + + + align:start position:0% +create your Sprint task list at a at a +meeting is everyone there or that's when + + align:start position:0% +meeting is everyone there or that's when + + + align:start position:0% +meeting is everyone there or that's when +you're saying not everyone's there + + align:start position:0% +you're saying not everyone's there + + + align:start position:0% +you're saying not everyone's there +we have + + align:start position:0% + + + + align:start position:0% + +tasks okay we have a week by what we + + align:start position:0% +tasks okay we have a week by what we + + + align:start position:0% +tasks okay we have a week by what we +want to get okay cool um and you had a + + align:start position:0% +want to get okay cool um and you had a + + + align:start position:0% +want to get okay cool um and you had a +meeting to do to create that okay U so + + align:start position:0% +meeting to do to create that okay U so + + + align:start position:0% +meeting to do to create that okay U so +then you have your daily standups at the + + align:start position:0% +then you have your daily standups at the + + + align:start position:0% +then you have your daily standups at the +end of the Sprint um you want to have a + + align:start position:0% +end of the Sprint um you want to have a + + + align:start position:0% +end of the Sprint um you want to have a +Sprint review which is basically the + + align:start position:0% +Sprint review which is basically the + + + align:start position:0% +Sprint review which is basically the +inverse of the Sprint planning meeting + + align:start position:0% +inverse of the Sprint planning meeting + + + align:start position:0% +inverse of the Sprint planning meeting +you go back and see what you made um + + align:start position:0% +you go back and see what you made um + + + align:start position:0% +you go back and see what you made um +hopefully you have a build and you just + + align:start position:0% +hopefully you have a build and you just + + + align:start position:0% +hopefully you have a build and you just +basically look at the build compare the + + align:start position:0% +basically look at the build compare the + + + align:start position:0% +basically look at the build compare the +build to the completed tasks and make + + align:start position:0% +build to the completed tasks and make + + + align:start position:0% +build to the completed tasks and make +sure it matches the other meeting um + + align:start position:0% +sure it matches the other meeting um + + + align:start position:0% +sure it matches the other meeting um +that you may or may not be doing is the + + align:start position:0% +that you may or may not be doing is the + + + align:start position:0% +that you may or may not be doing is the +agile retrospective and that's how did + + align:start position:0% +agile retrospective and that's how did + + + align:start position:0% +agile retrospective and that's how did +you work this week is anybody doing that + + align:start position:0% +you work this week is anybody doing that + + + align:start position:0% +you work this week is anybody doing that +is anybody at the end of their Sprint + + align:start position:0% +is anybody at the end of their Sprint + + + align:start position:0% +is anybody at the end of their Sprint +talking about basically talking about + + align:start position:0% +talking about basically talking about + + + align:start position:0% +talking about basically talking about +the processes of what you did and how + + align:start position:0% +the processes of what you did and how + + + align:start position:0% +the processes of what you did and how +you did + + align:start position:0% + + + + align:start position:0% + +it okay it's kind of what I expect + + align:start position:0% +it okay it's kind of what I expect + + + align:start position:0% +it okay it's kind of what I expect +um I think you're doing yourself a + + align:start position:0% +um I think you're doing yourself a + + + align:start position:0% +um I think you're doing yourself a +disservice if you're not doing that and + + align:start position:0% +disservice if you're not doing that and + + + align:start position:0% +disservice if you're not doing that and +in particular if you are doing that and + + align:start position:0% +in particular if you are doing that and + + + align:start position:0% +in particular if you are doing that and +you're making that a face-to-face + + align:start position:0% +you're making that a face-to-face + + + align:start position:0% +you're making that a face-to-face +meeting that's the time when you can + + align:start position:0% +meeting that's the time when you can + + + align:start position:0% +meeting that's the time when you can +talk about some of these interpersonal + + align:start position:0% +talk about some of these interpersonal + + + align:start position:0% +talk about some of these interpersonal +issues that's the time when you can talk + + align:start position:0% +issues that's the time when you can talk + + + align:start position:0% +issues that's the time when you can talk +about your feelings uh that's the time + + align:start position:0% +about your feelings uh that's the time + + + align:start position:0% +about your feelings uh that's the time +when you can can open up and and try to + + align:start position:0% +when you can can open up and and try to + + + align:start position:0% +when you can can open up and and try to +figure out what is about like why are + + align:start position:0% +figure out what is about like why are + + + align:start position:0% +figure out what is about like why are +some of these tasks not getting um taken + + align:start position:0% +some of these tasks not getting um taken + + + align:start position:0% +some of these tasks not getting um taken +on um who's not doing them and what's in + + align:start position:0% +on um who's not doing them and what's in + + + align:start position:0% +on um who's not doing them and what's in +their way uh from doing them but really + + align:start position:0% +their way uh from doing them but really + + + align:start position:0% +their way uh from doing them but really +it's not it's not about the it's not + + align:start position:0% +it's not it's not about the it's not + + + align:start position:0% +it's not it's not about the it's not +really about what's in their way it's + + align:start position:0% +really about what's in their way it's + + + align:start position:0% +really about what's in their way it's +difficult to talk about it's not about + + align:start position:0% +difficult to talk about it's not about + + + align:start position:0% +difficult to talk about it's not about +what's in their way but it might be + + align:start position:0% +what's in their way but it might be + + + align:start position:0% +what's in their way but it might be +about what outside of the project and + + align:start position:0% +about what outside of the project and + + + align:start position:0% +about what outside of the project and +outside of the team could be in their + + align:start position:0% +outside of the team could be in their + + + align:start position:0% +outside of the team could be in their +way and you can can work through some of + + align:start position:0% +way and you can can work through some of + + + align:start position:0% +way and you can can work through some of +those kind of issues + + align:start position:0% + + + + align:start position:0% + +so I'm done what I'd like you to do + + align:start position:0% +so I'm done what I'd like you to do + + + align:start position:0% +so I'm done what I'd like you to do +before you go and work in your teams is + + align:start position:0% +before you go and work in your teams is + + + align:start position:0% +before you go and work in your teams is +schedule a Sprint retrospective so think + + align:start position:0% +schedule a Sprint retrospective so think + + + align:start position:0% +schedule a Sprint retrospective so think +a look take a look at your Sprint at + + align:start position:0% +a look take a look at your Sprint at + + + align:start position:0% +a look take a look at your Sprint at +your Sprint process how long is your + + align:start position:0% +your Sprint process how long is your + + + align:start position:0% +your Sprint process how long is your +Sprint is it one week or two weeks um + + align:start position:0% +Sprint is it one week or two weeks um + + + align:start position:0% +Sprint is it one week or two weeks um +we've been assuming it's a one week week + + align:start position:0% +we've been assuming it's a one week week + + + align:start position:0% +we've been assuming it's a one week week +process onee Sprints um schedule a time + + align:start position:0% +process onee Sprints um schedule a time + + + align:start position:0% +process onee Sprints um schedule a time +period that everyone can attend and a + + align:start position:0% +period that everyone can attend and a + + + align:start position:0% +period that everyone can attend and a +Time an amount of time that they can + + align:start position:0% +Time an amount of time that they can + + + align:start position:0% +Time an amount of time that they can +attend that they can see each other face + + align:start position:0% +attend that they can see each other face + + + align:start position:0% +attend that they can see each other face +to face but not as NE are in the same + + align:start position:0% +to face but not as NE are in the same + + + align:start position:0% +to face but not as NE are in the same +room if you can be in the same room + + align:start position:0% +room if you can be in the same room + + + align:start position:0% +room if you can be in the same room +awesome if you can't try to figure out a + + align:start position:0% +awesome if you can't try to figure out a + + + align:start position:0% +awesome if you can't try to figure out a +time that you can chat using Google + + align:start position:0% +time that you can chat using Google + + + align:start position:0% +time that you can chat using Google +hangout or some other kind of video chat + + align:start position:0% +hangout or some other kind of video chat + + + align:start position:0% +hangout or some other kind of video chat +some other kind of face to-face video + + align:start position:0% +some other kind of face to-face video + + + align:start position:0% +some other kind of face to-face video +chat um make sure the meeting is focused + + align:start position:0% +chat um make sure the meeting is focused + + + align:start position:0% +chat um make sure the meeting is focused +on talking about your processes so don't + + align:start position:0% +on talking about your processes so don't + + + align:start position:0% +on talking about your processes so don't +talk about your game don't talk about + + align:start position:0% +talk about your game don't talk about + + + align:start position:0% +talk about your game don't talk about +the work that you've done talk about how + + align:start position:0% +the work that you've done talk about how + + + align:start position:0% +the work that you've done talk about how +you organize yourself um and in + + align:start position:0% +you organize yourself um and in + + + align:start position:0% +you organize yourself um and in +particular talk about your interpersonal + + align:start position:0% +particular talk about your interpersonal + + + align:start position:0% +particular talk about your interpersonal +matters talk about um basically + + align:start position:0% +matters talk about um basically + + + align:start position:0% +matters talk about um basically +communicate about communicating so talk + + align:start position:0% +communicate about communicating so talk + + + align:start position:0% +communicate about communicating so talk +about how you are talking to each other + + align:start position:0% +about how you are talking to each other + + + align:start position:0% +about how you are talking to each other +um and yeah I'm going to talk to you + + align:start position:0% +um and yeah I'm going to talk to you + + + align:start position:0% +um and yeah I'm going to talk to you +about this again in a couple weeks and + + align:start position:0% +about this again in a couple weeks and + + + align:start position:0% +about this again in a couple weeks and +in a couple weeks I'm going to give you + + align:start position:0% +in a couple weeks I'm going to give you + + + align:start position:0% +in a couple weeks I'm going to give you +some more um act once you're actually in + + align:start position:0% +some more um act once you're actually in + + + align:start position:0% +some more um act once you're actually in +the process of I think most of you right + + align:start position:0% +the process of I think most of you right + + + align:start position:0% +the process of I think most of you right +now are probably in the concepting phase + + align:start position:0% +now are probably in the concepting phase + + + align:start position:0% +now are probably in the concepting phase +pre-production phase right now you're + + align:start position:0% +pre-production phase right now you're + + + align:start position:0% +pre-production phase right now you're +still kind of figuring out your game you + + align:start position:0% +still kind of figuring out your game you + + + align:start position:0% +still kind of figuring out your game you +haven't quite like I guess you you guys + + align:start position:0% +haven't quite like I guess you you guys + + + align:start position:0% +haven't quite like I guess you you guys +are actually working on your back end + + align:start position:0% +are actually working on your back end + + + align:start position:0% +are actually working on your back end +because someone did the initial design + + align:start position:0% +because someone did the initial design + + + align:start position:0% +because someone did the initial design +for you uh the rest are probably still + + align:start position:0% +for you uh the rest are probably still + + + align:start position:0% +for you uh the rest are probably still +working out that design phase uh when I + + align:start position:0% +working out that design phase uh when I + + + align:start position:0% +working out that design phase uh when I +talk about this again you'll likely be + + align:start position:0% +talk about this again you'll likely be + + + align:start position:0% +talk about this again you'll likely be +in fullon um production mode and so some + + align:start position:0% +in fullon um production mode and so some + + + align:start position:0% +in fullon um production mode and so some +of the the activities I'm going to show + + align:start position:0% +of the the activities I'm going to show + + + align:start position:0% +of the the activities I'm going to show +you might hopefully help when you're + + align:start position:0% +you might hopefully help when you're + + + align:start position:0% +you might hopefully help when you're +doing these + + align:start position:0% +doing these + + + align:start position:0% +doing these +meetings any + + align:start position:0% + + + + align:start position:0% + +questions okay so it's 150 go ahead and + + align:start position:0% +questions okay so it's 150 go ahead and + + + align:start position:0% +questions okay so it's 150 go ahead and +take a few minutes to uh break and then + + align:start position:0% +take a few minutes to uh break and then + + + align:start position:0% +take a few minutes to uh break and then +the rest of the class is yours to work + + align:start position:0% +the rest of the class is yours to work + + + align:start position:0% +the rest of the class is yours to work +in your teams but still do + + align:start position:0% +in your teams but still do + + + align:start position:0% +in your teams but still do +this you can leave it you can leave it + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +not + + align:start position:0% + + + + align:start position:0% + +[Music] \ No newline at end of file diff --git a/B4xIxr3fB7c.txt b/B4xIxr3fB7c.txt new file mode 100644 index 0000000000000000000000000000000000000000..052ced21d233366122ab51900377e75e3cb23796 --- /dev/null +++ b/B4xIxr3fB7c.txt @@ -0,0 +1,1941 @@ +PROFESSOR: We are thundering +rapidly to the + +midpoint of the term. + +I think a week from this +coming Thursday will be + +exactly halfway, and the +halfway point is when I + +usually try, give or take a +day, to change gears very + +abruptly and start looking at +the symmetry of physical + +properties and tensors and +actual discussion of physical + +properties that are +anisotropic. + +So we'll be finishing +up our discussion of + +symmetry fairly quickly. + +We still have, however, some +major derivations to perform, + +and we'll get into one +of these today. + +Last time we had begun the +process of deriving what are + +called the point groups as +opposed to the plane groups. + +The plane groups were +combinations of symmetry with + +a lattice that extended +throughout a plane in space. + +A point group we've seen in the +form of two-dimensional + +point groups. + +We're now going to today derive +the three-dimensional + +point groups. + +And, again, the name stems from +the fact that these are + +clusters of symmetry about a +common point so that at very + +least that one point +in space stays put. + +So, hence, point groups-- + +these are symmetries +about a point. + +And to put some embellishing +adjectives on here, these will + +be the three-dimensional +crystallographic point groups. + +Because there are an infinite +number of point groups, we're + +considering just those +symmetries that can be + +combined with a lattice +and therefore are + +permissible to crystals. + +I'd like to point out in case +you've not been making much + +use of Buerger's book that we +actually are getting back to + +Buerger's treatment. + +We'll do some of the derivations +over the next few + +days with a little bit more +detail and with a slightly + +different procedure +than Buerger. + +But the bases covered +are the same. + +So let me just point out where +some of this material is in + +Buerger's book. + +Buerger does Euler's +Construction, and he does this + +in a once over lightly. + +I think this is not the +best part of the book. + +This is on pages 35 to 43. + +In particular, he sort of leaps +ahead quickly and just + +looks for one angle between +rotation axes and doesn't get + +the-- do specifically the ones +that are 90 degrees and are + +not as interesting. + +Some of the combination theorems +are in Chapter 6, and + +there you'll find the statement +that two reflections + +at an angle mu is equivalent +to a net rotation of mu, + +except Buerger doesn't +call them sigmas. + +He calls them m's. + +He uses the same symbol for +individual operations and for + +the symmetry of them, and I +think that's a little untidy. + +Also, the theorem that says that +if we have a mirror plane + +that's perpendicular to a +twofold rotation axis, that + +gives rise to inversion center +at the point of intersection. + +And then he launches into a +rather condensed version of + +the derivation of the point +groups on pages 59 to 68. + +Then, in Chapter 7, derives the +two dimensional lattices + +or the plane nets. + +This is on page 69 to 83. + +We've done that differently and +much more exhaustively by + +deriving the two-dimensional +plane groups and the lattices + +are part of the plane groups, +and we've gotten them + +automatically. + +There is a place where in the +derivation of the space + +lattices, he's a little bit +incomplete and actually does + +something that's wrong A-ha-- + +I showed Buerger was wrong +at one place in his book. + +But anyway, this is where the +material that we're covering + +now is mentioned in +Buerger's book. + +Last time, we had hit +a new surprise. + +We had asked if we take the +basic rotational symmetries + +and add an inversion to +something like three-- + +so, three is a subgroup, +the operation of + +inversion is an extender. + +We found that there was a new +operation that came up, and + +this was a rotoinversion +operation. + +And then the resulting point +group, which we called 3-bar-- + +the symbol itself, 3-bar, is +a threefold rotoinversion. + +And if we were not clever +enough to invent a + +rotoinversion operation, we +would have stumbled headlong + +over it in adding inversion +as an extender + +to a threefold axis. + +And a rotoinversion axis is +something that involves in + +general rotating through some +angle alpha to get from a + +first object to a second object +of the same handedness + +and then not yet putting it +down, first inverting it + +through axis-- + +through a point on the axis-- + +to get a second object. + +I shouldn't call this second +because this is not rotation + +with inversion simultaneously +but a two step operation. + +So we rotate from 1 to this +virtual object also of same + +handedness and then before +putting it down, we invert it + +to get number two, which +is left handed. + +And the operation of getting +there in two steps but in one + +repetition is the operation +of rotoinversion. + +That operation was one of the +members of the group that + +results when you add inversion +as an extender to 3. + +But, really, this was not +something that was a new sort + +of symmetry element. + +It was an operation that came +up, but we could regard the + +point down that we've labeled +3-bar as simply a threefold + +axis with an inversion +center sitting on it. + +But then we looked +at another one. + +And by anticipation, I said +we ought to look at these. + +And we looked at what happened +when we took a fourfold + +rotoinversion operation where we +would take the first object + +number one, rotate it through +90 degrees, and + +not yet put it down. + +We'd first invert it through a +point on an axis, and we got + +one that was 90 degrees away +but pointing down in of + +opposite handedness. + +If we repeated that operation +several times, we found that + +we got two objects up above a +plane normal to the rotation + +part of the operation and +passing through the point, + +which we inverted. + +So there's one right handed one +up here, a second right + +handed one up here, and then two +down below, which were of + +opposite chirality, +number 3 and 4. + +And that is an entirely +new beast. + +We have no way of describing +the relation between these + +four objects other than saying +rotate, don't put it down, + +first invert. + +Rotate, don't put it down, +first invert again. + +So this is something +entirely new. + +It's a two step operation. + +You cannot describe it any more +simply than saying take + +two steps to do the repetition +in the same sense that the + +glide plane that we discovered +in the plane groups had a step + +of translation followed +immediately by reflection, and + +that was a new sort +of operation. + +So here's another example +of a two-step operation. + +The symbol for this point group +is 4-bar, and the symbol + +for it-- if you want to indicate +its locus, is, it's + +got a squareness to it because +these objects as mutually are + +separated by 90 degrees, but it +really has only a twofold + +symmetry, so the symmetry +for a 4-bar axis. + +It's not really an +axis at all. + +It's a 4-bar point, +because only a + +point is left invariant. + +But the symbol for a 4-bar +"axis" is this square with a + +little twofold axis +inscribed in it. + +Alright. + +We ought to really, then, step +back and ask how many + +different rotoinversion axes +there might be, and add these + +to our bags of tricks. + +And what I'm going to invite you +to do is to examine this + +systematically on a problem set +which I will pass around, + +along with several other +problems for your + +consideration, as well. + +And having stumbled onto that +combination, another thing we + +might ask to broaden our bag of +tricks still further is to + +say is there such a thing as +a rotoreflection axis? + +And we called n-bar +a rotoinversion. + +I wrote a reflection axis is +indicated by an n with this + +little squiggle on top. + +Anyone who has studied Spanish +realizes that the proper name + +for the squiggle is a +tilde, T-I-L-D-E. + +And this would be an operation +where there's a locus in which + +we'll perform the reflection +part of the operation, so this + +would be a 2 step operation that +involves taking a first + +one and rotating it to a virtual +object number two but + +not putting it down. + +Before putting it down, we will + +reflect in a planar locus. + +So this is number two, and it +will be of opposite chirality. + +So that's another operation that +involves rotation coupled + +as one part of a step that +involves R, the second of our + +three translation free +operations, namely reflection + +and inversion. + +So are these something +we should consider? + +What I've invited you to do is +to draw out for n equals 1 to + +8 the patterns produced by +rotoinversion and the patterns + +created by rotoreflection, and +then see if you regard these + +as new operations or whether +they can be broken down into + +the simultaneous presence of +more than one of our old + +friends such as 3-bar being a +plain old threefold axis with + +an inversion sitting on it. + +The fact that I'm asking you +take your time to do this + +suggests that yes, you are +going to find some + +rotoinversion and rotoreflection +axes, which are + +inherently 2 step operations +and can't be decomposed. + +What I'd like to do now, then, +is to systematically look at + +the axial combinations. + +These are of the form n one, +two, three, four, and six and + +the dihedral symmetries. + +These are of the form n22, or +just 32 in the case of the one + +with the threefold axis. + +And then the two cubic +arrangements 23, twofold axis + +out of the face normal to a +cube, threefold axes out of + +all of the body diagonals, +and 432. + +And what I'm going to do with +you is to use these as + +worksheets to guide the logic +of what we're doing, and we + +won't do every single +one of them. + +I think once we do a few, the +general principle is clear and + +the results there +are before you. + +But what we'll take, then, is +the axes n, the axes n22, and + +then the two cubic symmetries +23 and 432. + +Then, finally, we found 4-bar +as a different rotation + +axis-like symmetry element, so +I'll add that to the list. + +Then consider what we can add +to these symmetries as + +extenders, and these are an +additional element that we can + +add to what is already a + +self-contained nice little group. + +We muck things up by introducing +another operation, + +and then we'll have to take +combinations of that operation + +with all the symmetry elements +that are there in the parent + +subgroup and see what new +symmetry elements arise. + +The ground rules in these +additions are fairly simple + +but nevertheless profound. + +The addition of the extender +cannot create any new symmetry + +axes by its operation, and the +reason for that should be + +quite clear. + +We obtained these combinations +of rotation axes using Euler's + +principle, and that was +thorough and orderly, + +systematic and complete. + +These are the only +arrangements of + +crystallographic rotation +axes that are possible. + +So if we add an extender that +creates, for example, a new + +twofold axis in n22, it's either +going to be something + +that we already have in this +list, and therefore not + +interesting, or something +that just cannot + +constitute a group. + +We'll take combinations of +operations and we will never + +find a closed finite set. + +So if we add a mirror operation, +a reflection + +operation as an extender, the +addition of the reflection + +operation sigma must be either +perpendicular to the axis. + +And what that's going to do is +just flip the top part of the + +rotation axis and reflect it +down to the bottom axis. + +Nothing new was created. + +And it could alternatively be +parallel to the axis and + +passing through it. + +In that case, we've already seen +the consequences of this + +addition in deriving the +two-dimensional point groups, + +namely to 2mm, 3m, +4mm, and 6mm. + +No new axis is created. + +One of the additions that is +something we mentioned last + +time is that in the case of the +dihedral groups where we + +have an n-fold axis and +then twofold axes + +arranged in some fashion-- + +not in some arbitrary fashion. + +It's going to be 2 pi over n +times 1/2, depending on the + +n-fold axis-- + +we could pass the +mirror operation + +through the twofold axis. + +And that's what we'll call +a vertical mirror plane. + +But when there's more than one +axis present, we could also + +put the reflection operation +diagonally in between the + +twofold axes. + +So we're going to refer to this +as a diagonal mirror. + +It's snaked in between the +axes that are present. + +So, perpendicular reflection +operation as an extender, one + +parallel to the axis and passing +through it, or one + +that is diagonal passing +in between them. + +And finally, that exhausts +what we can do with + +reflection, but we could +add inversion. + +And if we're not going create +new axes, and we're going to + +get a point group-- a finite +set of objects-- + +the inversion center has to be +on one of the single axis, + +namely these groups n, or at the +point of intersection, if + +there's more than one. + +So there's the job +laid out for us. + +And we've got two theorems to +aid us in quickly finding the + +new operations that arise-- + +in effect, taking a shortcut +to establish the group + +multiplication table, and the +two theorems are as follows. + +We saw that if you take a +rotation operation A pi, that + +takes a first object that's +right handed and rotates it to + +a second object that is +also right handed. + +Then follow that by reflection +in a mirror plane that is + +perpendicular to the axis. + +The net effect of going from 1 +to number 3, which is left + +handed, is to create an +inversion center at the point + +of intersection. + +So there's a theorem that we +can write down once and for + +all and say that A pi followed +by reflection in a mirror + +plane that's perpendicular to +axis A has, as a net effect, + +the operation of inversion. + +And if this is not a twofold +axis, it's something like a + +fourfold axis or a sixfold +axis, that contains the + +operation A pi as part of the +operations contained in that + +axis, and that's going +to create an + +inversion center as well. + +So for any evenfold axis, add a +perpendicular mirror plane, + +and automatically the inversion +center comes up. + +And we can permute the order +of these operations if we + +rotate by 180 degrees and then +invert the net effect is + +reflection in the perpendicular +mirror plane. + +So this is something that you +permute around into three + +different combinations. + +Does the order of the operation +make a difference? + +And the answer is no, the +order is not important. + +For example, rotating and then +reflecting is the same as + +reflecting and then +rotating it. + +It went up at the same +point, number 3. + +Remember a fancy word for this +when we define what's meant by + +a group, that these groups are +going to be what's called + +Abelian, and an Abelian group +is where any combination of + +operations a followed by b is +identical to b followed by a. + +I told you that great joke among +mathematicians, what is + +purple and commutes? + +And the answer is an +Abelian grape. + +Ha, ha, ha-- + +I think that's stupid, but it +drives mathematicians into + +guffaws of laughter. + +A second theorem, and this is +one that we've already seen in + +two dimensions, is that if you +take an operation A alpha, + +pass a reflection operation +sigma 1 through it, that to + +the effect of that is going to +be another mirror plane that + +is alpha over 2 away +from the first. + +Notice I'm a little bit sloppy +in talking about reflection + +operation and mirror plane +because if a reflection + +operation is there, that's all +I need to have to say that + +this is the locus of a symmetry + +point, a mirror plane. + +So this is another one. + +Do you think that this an +Abelian combination to say + +that A alpha followed by sigma +1 is equal to sigma 2. + +Is this Abelian? + +AUDIENCE: No. + +PROFESSOR: No, it's not. + +And how do you answer that? + +Not through any means more +profound than just drawing it + +out and seeing what you get. + +Let's take 3n as an example. + +So let's do the operation. + +In this order, do the rotation +A 2 pi over 3 to go from this + +one up to this one, and then +let's reflect across this + +horizontal mirror plane. + +So this is 1 right handed, +this is 2 right handed + +reflect, here's number three +and it's left handed. + +So that's A 2 pi over +3 followed by + +reflection in sigma 1. + +And if we do the operations in +reverse order, reflect in + +sigma 1 to go up to here, so +this would be 2 prime and then + +rotate by 120 degrees. + +We would go to here to here, +and that is not the same + +location as this one. + +So this is not equal to sigma +1 followed by A 2 pi over 3. + +How can you tell when is the +combination of operations is + +going to be Abelian and +when is it not? + +It sounds rather clumsy to +state it in words, but + +whenever the two symmetry +operations leave each other + +unmoved, then you can +permute the order. + +For example, in this combination +here the rotation + +leaves the mirror +plane unchanged. + +It just spins around +in its own plane. + +The mirror plane leaves the +rotation unchanged, it just + +reflects it end to end. + +Here this rotation axis and +these mirror planes obviously + +do not leave each other +unchanged because the + +threefold axis rotates +the mirror plane to + +two other new locations. + +So whenever that's the case, if +the operations do not leave + +each other unchanged, the order +makes a difference. + +So that's a useful thing +to keep in mind. + +Let's now turn to these sheets +that I passed out, and you + +might want to unstaple them +because they're designed to go + +side by side, and there +are three pages. + +What I've done across the top +of the pages is to give the + +different combinations of +crystallographic rotation axes + +that are possible. + +So going from the first sheet +across to the last, there's + +the rotation axes +by themselves-- + +one, two, three, +four, and six. + +Then there are the groups of +the form n22, 222, 32, 422, + +622, and then the two cubic +combinations 23 and 432. + +So there are the 11 possible +combination of + +crystallographic rotation axes, +and stuck off by itself + +at the end is the +oddball 4-bar. + +For the axes by themselves, the +diagonal mirror addition + +is not defined. + +The diagonal mirror position +by definition snakes in + +between axes that are there +in the axial combination. + +If there's only one axis, +that's not defined. + +But you could add a horizontal +mirror plane. + +A horizontal mirror planes +adds a onefold axis. + +It's just a mirror plane. + +So that's called m in +the international + +notation for mirror. + +And it's called C sub S, C +because it's a cyclic group, + +and the S stands for Spiegel. + +That's the Schoenflies +notation. + +If we add a-- + +take two and add a horizontal +mirror plane-- + +this is the thing that we +sketched out here-- + +this gives a pattern of four +objects, two that are up above + +the mirror plane of one +chirality, two down below the + +mirror plane of opposite +chirality. + +These projections of the +patterns are down along the + +rotation axis, and when you +see a dot in a circle, the + +circle represents the point that +is down and the dot is + +one that's up on top. + +So there are two pairs +of objects-- + +two right handed ones that are +up and two left-handed ones + +that are down. + +And that, in international +notation, is 2/m the twofold + +axis is over a mirror plane. + +So that's the way to make +sense of the symbol and + +remember what it means. + +In the Schoenflies +notation at C2. + +You've added a horizontal mirror +plane as an extender. + +Going down the remaining ones +in that list because they're + +all very, very similar-- + +add a mirror plane to a +threefold axis, the triangle + +is reflected down to a triangle +of motifs of opposite + +chirality, so that's 3 over m. + +For sure, it's called 6-bar, but +let's forget about that. + +The Schoenflies notation C3H, +and similarly there's a 4 over + +m, a square above, and a square +of opposite handedness + +below the mirror plane. + +The horizontal mirror plane in +all of these cases is shown as + +a bold line. + +They've added fainter vertical +lines to give + +you an angular reference. + +Don't be confused by that +in the Xerox copy-- + +the weight of the lines +is not distinguished. + +So the only symmetry element +in 4 over m, for example, + +should be shown by this solid +bold circle that is in the + +plane of the paper. + +The two crossed lines are +lighter and those are just as + +mutual orientations. + +And finally, there's another +one of this form + +which is 6 over m. + +On all of the evenfold +additions-- that is, to say + +everything but 3m-- + +if you add that horizontal +mirror plane, it's going to be + +perpendicular to an +operation A pi. + +Therefore, inversion pops up +as one of the operations in + +the group, and 2 over m, 4 +over m, 6 over m, those + +regular polyhedra of objects-- + +can be inverted through the +point of intersection of the + +axis in the mirror plane, and +that leaves the set unchanged. + +So if we go down to the bottom +of the list and say, can we + +add inversion to these axial +arrangements, in the case of + +2, 4, and 6-- + +no, adding inversion doesn't +give you anything new, because + +that's already there in the +groups of the form CNH, or + +2/m, 4/m, 6/m. + +Diagonal is not defined, so the +only additional one that + +we could pick up by adding +inversion is adding inversion + +to a threefold axis, +and that's one we + +did the other day. + +Adding inversion to a threefold +axis gives us three + +that are up of one handedness, +three that are down of + +opposite handedness, and +the orientation of + +the triangle is skewed. + +That is called 3-bar. + +But it's just nothing more than +a threefold axis with an + +inversion center +sitting on it. + +Schoenflies' notation is C3i. + +Then the only other additions to +the single axes are adding + +the mirror plane in a vertical +fashion passing through the + +axis, and these we've already +seen in two dimensions so we + +don't have to spend +much time on them. + +There's 2 mm, which is C2V. + +3m-- + +all the mirror planes result +upon adding a single mirror + +plane to the threefold axis-- + +4 mm, and 6 mm. + +These are just three-dimensional +extensions + +parallel to the axis of the +symmetry that we already + +derived for a plane +in space in the + +two-dimensional point groups. + +So we're almost half done. + +It's easy, isn't it? + +Any questions at this point? + +So the only ones that are really +new that we haven't + +seen already in two dimensions +are the rotation axis + +perpendicular to the +mirrored plane. + +That brings us to roughly the +middle of the second sheet, + +and the arrangement of axes 222 +represents three mutually + +orthogonal twofold axes. + +If we add a horizontal mirror +plane, that's going to put an + +inversion center at the point +of intersection because that + +horizontal reflection is going +to be sitting normal to a + +twofold axis. + +And then since the other twofold +axes see an inversion + +center sitting on it, there's +a mirror plane perpendicular + +to those other twofold axes. + +So adding again to go through +that again, adding inversion + +to the point of intersection of +the twofold axes creates a + +mirror plane perpendicular to +each of those twofold axes. + +So it becomes 2/m 2/m 2/m-- + +each of the twofold axes +acquires a different sort of + +mirror plane perpendicular +to its orientation. + +And 2/m 2/m 2/m, even though +I love saying it, + +is kind of a mouthful. + +So that's very often abbreviated +to just mmm, which + +really is a nice exclamation +when you see what a lovely + +symmetry it is. + +The pattern shown in the diagram +to the left is just + +the pattern of 222 with the +objects reflected up or + +reflected down, and you +get a total of 8. + +That means that there are eight +operations in the group, + +and you can add up quickly +what they are. + +They are the three operations +of rotating by pi, the + +operation of identity, then +three mirror planes because + +the mirror planes all +indistinct, and then the + +operation of inversion. + +So there are the eight +operations that are present + +that generate the objects +from a single one. + +Add a horizontal mirror plane to +32 and you get a threefold + +axis perpendicular to the +threefold axis, so you write + +that as 3m. + +That mirror plane now passes +through the horizontal twofold + +axes, and a twofold axis with a +mirror plane passing through + +it wants another mirror plane +90 degrees away, so a new + +mirror plane pops up passing +through each of the twofold + +axes and perpendicular to the +horizontal mirror plane. + +Those mirror planes are +in the same direction + +as the twofold axis. + +They're not perpendicular to it, +and when symmetry elements + +are parallel to a common +direction you write them out + +on the same line, so here's a +case of a mixed metaphor. + +One mirror plane that's +perpendicular to an axis, the + +threefold axis, so you write +that as 3 over m. + +The other twofold axes have +mirror points passing through + +them, so you write that as 2m +and the threefold axes makes + +all of those 2m symmetries +equivalent to one another. + +Pattern, and this is true for +all of these symmetries, is + +nothing more than the pattern +of the subgroup repeated by + +the one operation that you've +added as an extender . + +So if you look at the pattern of +32, object all of the same + +chirality, all apparently +up and down, and add the + +horizontal mirror plane. + +The one that is up goes down, +the one that's down goes up, + +and you get a set of +four around each + +of the twofold axes. + +422 behaves very similarly. + +The pattern is just the pattern +of 422 reflected in a + +plane, so you have a +set of 16 objects-- + +eight of them up of one +chirality, those are the solid + +dots, if you will, and then +another two, four, six, eight + +that are down of opposite +chirality. + +You have a mirror plane that +you added as the horizontal + +mirror plane perpendicular +to the fourfold axis. + +All of the horizontal twofold +axes see a mirror plane + +passing through them. + +So they've got to have a mirror +plane that's 90 degrees + +away, and those are the vertical +mirror planes. + +Either the point is obvious now +or you're not following me + +at all, so I'll simply say on +the left-hand column of the + +final sheet, 622 with a +horizontal mirror plane goes + +to 6/m, 2/m, 2/m, called +D6h in Schoenflies. + +I'll leave the cubic +ones until last. + +They're not nearly as +bad as they seem. + +But obviously they have a lot +of symmetry all over the + +place, and we'll want to take a +closer look at the patterns. + +The next extender is a vertical +mirror plane, and + +we've already got the groups of +the form cnv, because they + +are just extensions in a third +dimension of one set we've + +seen in two dimensions. + +If we try adding the vertical +mirror plane, which is defined + +as passing through the principal +axis of high + +symmetry and perpendicular to +the twofold axes, we've + +already encountered those in +every group except 32. + +2/m, 2/m, 2/m already has the +vertical mirror plane. + +The same is true of 3/mm2. + +The same is true of 4/m, 2/m, +2/m and 6/m, 2/m, 2/m. + +The vertical mirror plane comes +in automatically when we + +add the horizontal mirror plane +as the extender, So + +nothing new there at all. + +And now we come to one +that is interesting. + +This is the diagonal +mirror plane. + +And I'll do this one slowly +and then in some detail + +because it's another example +of how we would trip over + +something if we were not clever +enough to think of it. + +Let me begin by drawing the +three orthogonal axes of 222. + +So we have one object that's up +and one object that's down. + +The twofold axis perpendicular +to the board will take this + +one that's down and rotate it +to here and take this one + +that's up and rotate +it to here. + +So that is the pattern of 222. + +We can snake a mirror plane in +between the twofold axes, and + +a mirror plane passing through +the vertical twofold axis has + +to be accompanied by one that's +90 degrees away, half + +the throw of the axis, which +comes from our theorem that + +says A pi dot sigma vertical +has to be equal to a sigma + +prime that's vertical and pi/2 +away from the first. + +In terms of the pattern, this +second mirror plane that comes + +up is going to reflect this one +across to here, it's going + +to reflect this one across to +here, it's going to take this + +one and reflect it over to here, +and take this one and + +reflect it to the +right, as well. + +So now we've got a total +of eight objects. + +This one is right handed, and +this one is also right handed + +because we repeated +it by rotation. + +Then we reflected that pair, so +these two are left handed, + +and reflect it across the other +diagonal mirror plane. + +They're back to right handed +again, and these have to be + +left handed as well, so +there's the pattern. + +Is there an inversion center +in this pattern? + +The answer is no, because there +is no mirror plane that + +is perpendicular to a twofold +axis, so this point group has + +no inversion in it. + +It's said to be acentric, +without a inversion center. + +Do we know how everything is +related to everything else? + +We know how this one +is related to this + +one by twofold rotation. + +We know how this one is related +to this one, and + +that's by reflection across +the mirror plane. + +How is the first one related +to this one? + +How do you get it through 90 +degrees and then pop it down + +and change the chirality? + +AUDIENCE: [INAUDIBLE]? + +PROFESSOR: You can't do +that in one step. + +You've got to do just what +I said in words. + +Rotate it 90 degrees, don't put +it down yet, and reflect + +it down in a horizontal +mirror plane. + +This horizontal mirror plane +is not a symmetry element, + +it's part of the operation +that's necessary to get us + +from this guy over to this guy +of opposite chirality. + +So this is an example +a new type of + +operation, a 2 step operation. + +This is a 90-degree +rotoreflection axis. + +And again, I feel compelled to +put the axis in quotation + +marks, because really it's a +pair of operations that leaves + +only a point unmoved, +so it's really a + +point symmetry element. + +There's another way of +describing the same thing, and + +that would be rotoinversion. + +We could rotate by 90 degrees in +the reverse sense, not yet + +put it down, and invert, +and we get, again, + +the relation between-- + +what did I do? + +Rotate it here, yes-- + +rotate to here and then invert, +and we got that one. + +So that's another way of +defining the relation. + +A 90-degree rotoreflection +is a minus 90-degree + +rotoinversion. + +So you pays your money and you +takes your choice, and what + +the groundbreakers who went +before us did was to take + +rotoinversion. + +as the operation to survive. + +So here is, if we were not smart +enough to invent it, our + +4-bar rotoinversion axis. + +So if we hadn't been clever +enough-- and it would take a + +pretty clever, devious mind to +invent a 2 step rotoinversion + +operation-- + +as soon as we added this sort of +extender, a diagonal mirror + +plane to a group of the form +n22, we would have found that + +there was a new sort of +transformation that could not + +be described any more simply +than to say take + +two steps to do it. + +Rotate 90 degrees +and then invert. + +So we have to add the operation +of A pi over 2-bar + +to our basic bag of tricks +for generating patterns. + +The group 32 is also a group to +which we can add a diagonal + +mirror plane. + +And if you do that, again, the +bold lines that are mirror + +planes in that group and the +axes that are faint lines are + +easy to mix up. + +But if we examine that group +without the confusing lines, + +here are the twofold axes. + +And remember that they are all +equivalent to one another by + +the threefold axis. + +So this axial group +is the group 32. + +If we put down a mirror plane +interleaved between the + +twofold axes, notice that +each of those mirror is + +perpendicular to +a twofold axis. + +So we can write this as 2/m. + +2/m means there's an inversion +center at the intersection of + +the twofold axes with +the mirror planes. + +And a inversion center sitting +on a threefold axis makes it a + +3-bar axis, so this group +is called 3-bar 2/m. + +And the pattern is what a +twofold axis would do. + +These would be up-down-right +ones. + +Reflect those and you get an +up-down pair of left ones. + +Reflect again and you get +an up-down pair of + +right-handed ones. + +Reflect yet again, and you +get an up-down pair + +of left-handed ones. + +Reflect still once more, and +you get a down-up pair of + +right-handed ones. + +One more time, up-down +left-handed ones. + +So you get a total of 2, +4, 6, 8, 10, 12 points. + +So this is 3-bar 2/m in +Schoenflies notation D3-- + +that's the symbol 32-- + +with a diagonal mirror +plane added. + +You indicate that by a +d in the subscript. + +OK. + +I think that's probably a point +where you're more than + +ready for a break. + +We've got very few yet to do. + +One surprise is that if you add +diagonal mirror planes to + +422 and 622, you get perfectly +lovely exquisite groups but + +they're not crystallographic, +so we don't + +include them in our list. + +But we'll discuss them when we +come back, and then take a + +look also at the cubic +symmetries. + +Impossible to draw, but really +not all that difficult to + +understand. + +So let's stop at this point +and take a stretch. + +People are stretching already. + +They need it. + +We'll resume in 10 +minutes' time. \ No newline at end of file diff --git a/BKo57m-uU1k.txt b/BKo57m-uU1k.txt new file mode 100644 index 0000000000000000000000000000000000000000..1cfed89a9f75ab26e6e920031b9964fb1f222634 --- /dev/null +++ b/BKo57m-uU1k.txt @@ -0,0 +1,10443 @@ +align:start position:0% + +foreign + + align:start position:0% + + + + align:start position:0% + +so a quick problem + + align:start position:0% + + + + align:start position:0% + +you might want to grab a pen and paper + + align:start position:0% +you might want to grab a pen and paper + + + align:start position:0% +you might want to grab a pen and paper +and it I think it's not that hard but + + align:start position:0% +and it I think it's not that hard but + + + align:start position:0% +and it I think it's not that hard but +let's just ask + + align:start position:0% + + + + align:start position:0% + +let's say we have this function which is + + align:start position:0% +let's say we have this function which is + + + align:start position:0% +let's say we have this function which is +just the two Norm of x + + align:start position:0% +just the two Norm of x + + + align:start position:0% +just the two Norm of x +from RN to R + + align:start position:0% + + + + align:start position:0% + +right so everybody knows this function + + align:start position:0% +right so everybody knows this function + + + align:start position:0% +right so everybody knows this function +of course it's the square root of X1 + + align:start position:0% +of course it's the square root of X1 + + + align:start position:0% +of course it's the square root of X1 +squared up to X N squared + + align:start position:0% +squared up to X N squared + + + align:start position:0% +squared up to X N squared +right so a vector goes in the scalar + + align:start position:0% +right so a vector goes in the scalar + + + align:start position:0% +right so a vector goes in the scalar +comes out and my simple question is what + + align:start position:0% +comes out and my simple question is what + + + align:start position:0% +comes out and my simple question is what +is the gradient + + align:start position:0% +is the gradient + + + align:start position:0% +is the gradient +of this function + + align:start position:0% +of this function + + + align:start position:0% +of this function +and the reason why I'm putting this up + + align:start position:0% +and the reason why I'm putting this up + + + align:start position:0% +and the reason why I'm putting this up +in part is because I suspect everybody + + align:start position:0% +in part is because I suspect everybody + + + align:start position:0% +in part is because I suspect everybody +in the room can do this the 1802 way + + align:start position:0% +in the room can do this the 1802 way + + + align:start position:0% +in the room can do this the 1802 way +with indices and if you'd like to do it + + align:start position:0% +with indices and if you'd like to do it + + + align:start position:0% +with indices and if you'd like to do it +that way because that's where your + + align:start position:0% +that way because that's where your + + + align:start position:0% +that way because that's where your +comfort is that's fine + + align:start position:0% +comfort is that's fine + + + align:start position:0% +comfort is that's fine +but I think the real challenge is if you + + align:start position:0% +but I think the real challenge is if you + + + align:start position:0% +but I think the real challenge is if you +to kind of exercise what you've learned + + align:start position:0% +to kind of exercise what you've learned + + + align:start position:0% +to kind of exercise what you've learned +so far is to see if you can do this + + align:start position:0% +so far is to see if you can do this + + + align:start position:0% +so far is to see if you can do this +without indices that what I call the + + align:start position:0% +without indices that what I call the + + + align:start position:0% +without indices that what I call the +grown-up way right there's no right and + + align:start position:0% +grown-up way right there's no right and + + + align:start position:0% +grown-up way right there's no right and +wrong + + align:start position:0% +wrong + + + align:start position:0% +wrong +um if you get the right answer that's + + align:start position:0% +um if you get the right answer that's + + + align:start position:0% +um if you get the right answer that's +fine but of course I think that that I + + align:start position:0% +fine but of course I think that that I + + + align:start position:0% +fine but of course I think that that I +think that the the comfortable way is is + + align:start position:0% +think that the the comfortable way is is + + + align:start position:0% +think that the the comfortable way is is +well comfortable for everybody and the + + align:start position:0% +well comfortable for everybody and the + + + align:start position:0% +well comfortable for everybody and the +grown-up way takes some practice so let + + align:start position:0% +grown-up way takes some practice so let + + + align:start position:0% +grown-up way takes some practice so let +me put this up and I'll go through it in + + align:start position:0% +me put this up and I'll go through it in + + + align:start position:0% +me put this up and I'll go through it in +a moment so + + align:start position:0% +a moment so + + + align:start position:0% +a moment so +a simple question the gradient of this + + align:start position:0% +a simple question the gradient of this + + + align:start position:0% +a simple question the gradient of this +of this function and + + align:start position:0% +of this function and + + + align:start position:0% +of this function and +I think the 1802 way might be to start + + align:start position:0% +I think the 1802 way might be to start + + + align:start position:0% +I think the 1802 way might be to start +with the first component but pretty + + align:start position:0% +with the first component but pretty + + + align:start position:0% +with the first component but pretty +quickly you realize that every + + align:start position:0% +quickly you realize that every + + + align:start position:0% +quickly you realize that every +component's the same right so you you + + align:start position:0% +component's the same right so you you + + + align:start position:0% +component's the same right so you you +might start calculating for example d + + align:start position:0% +might start calculating for example d + + + align:start position:0% +might start calculating for example d +dx1 + + align:start position:0% +dx1 + + + align:start position:0% +dx1 +of the square root of X1 squared plus X + + align:start position:0% +of the square root of X1 squared plus X + + + align:start position:0% +of the square root of X1 squared plus X +N squared + + align:start position:0% +N squared + + + align:start position:0% +N squared +right and + + align:start position:0% +right and + + + align:start position:0% +right and +you know using all the calculus you + + align:start position:0% +you know using all the calculus you + + + align:start position:0% +you know using all the calculus you +remember the derivative of something to + + align:start position:0% +remember the derivative of something to + + + align:start position:0% +remember the derivative of something to +the one-half is the same thing to the + + align:start position:0% +the one-half is the same thing to the + + + align:start position:0% +the one-half is the same thing to the +negative one-half + + align:start position:0% + + + + align:start position:0% + +right and then you would + + align:start position:0% +right and then you would + + + align:start position:0% +right and then you would +you would get 2x1 so this would be one + + align:start position:0% +you would get 2x1 so this would be one + + + align:start position:0% +you would get 2x1 so this would be one +times two x one + + align:start position:0% +times two x one + + + align:start position:0% +times two x one +right and you would have X1 over the + + align:start position:0% +right and you would have X1 over the + + + align:start position:0% +right and you would have X1 over the +square root of X1 squared plus xn + + align:start position:0% +square root of X1 squared plus xn + + + align:start position:0% +square root of X1 squared plus xn +squared okay and it wouldn't take you + + align:start position:0% +squared okay and it wouldn't take you + + + align:start position:0% +squared okay and it wouldn't take you +long to realize that if you did X2 + + align:start position:0% +long to realize that if you did X2 + + + align:start position:0% +long to realize that if you did X2 +there's no real difference and before + + align:start position:0% +there's no real difference and before + + + align:start position:0% +there's no real difference and before +you knew it you would find out that + + align:start position:0% +you knew it you would find out that + + + align:start position:0% +you knew it you would find out that +the gradient of course would be the + + align:start position:0% +the gradient of course would be the + + + align:start position:0% +the gradient of course would be the +vector x divided by its length that + + align:start position:0% +vector x divided by its length that + + + align:start position:0% +vector x divided by its length that +gives you every com right and that would + + align:start position:0% +gives you every com right and that would + + + align:start position:0% +gives you every com right and that would +be the what I would call the 1802 way + + align:start position:0% +be the what I would call the 1802 way + + + align:start position:0% +be the what I would call the 1802 way +and it's not so bad okay but in this + + align:start position:0% +and it's not so bad okay but in this + + + align:start position:0% +and it's not so bad okay but in this +class we're trying to see if we can + + align:start position:0% +class we're trying to see if we can + + + align:start position:0% +class we're trying to see if we can +avoid using indices sometimes you can't + + align:start position:0% +avoid using indices sometimes you can't + + + align:start position:0% +avoid using indices sometimes you can't +many times you can right and so we want + + align:start position:0% +many times you can right and so we want + + + align:start position:0% +many times you can right and so we want +to emphasize the ability to not use + + align:start position:0% +to emphasize the ability to not use + + + align:start position:0% +to emphasize the ability to not use +indices + + align:start position:0% +indices + + + align:start position:0% +indices +okay and so I don't know has anyone + + align:start position:0% +okay and so I don't know has anyone + + + align:start position:0% +okay and so I don't know has anyone +already written it out for the or + + align:start position:0% +already written it out for the or + + + align:start position:0% +already written it out for the or +convince themselves they could do it + + align:start position:0% +convince themselves they could do it + + + align:start position:0% +convince themselves they could do it +without indices yet + + align:start position:0% +without indices yet + + + align:start position:0% +without indices yet +has anyone done it yet + + align:start position:0% +has anyone done it yet + + + align:start position:0% +has anyone done it yet +but you think you can do it + + align:start position:0% +but you think you can do it + + + align:start position:0% +but you think you can do it +so so + + align:start position:0% +so so + + + align:start position:0% +so so +I'm going to write down + + align:start position:0% +I'm going to write down + + + align:start position:0% +I'm going to write down +R is equal to the length of x + + align:start position:0% +R is equal to the length of x + + + align:start position:0% +R is equal to the length of x +okay and + + align:start position:0% +okay and + + + align:start position:0% +okay and +and therefore our our squared is X + + align:start position:0% +and therefore our our squared is X + + + align:start position:0% +and therefore our our squared is X +transpose X right this is sort of the + + align:start position:0% +transpose X right this is sort of the + + + align:start position:0% +transpose X right this is sort of the +the linear algebra way to set things up + + align:start position:0% +the linear algebra way to set things up + + + align:start position:0% +the linear algebra way to set things up +right and then I'm just going to take + + align:start position:0% +right and then I'm just going to take + + + align:start position:0% +right and then I'm just going to take +the differential of both sides and get 2 + + align:start position:0% +the differential of both sides and get 2 + + + align:start position:0% +the differential of both sides and get 2 +r d r + + align:start position:0% +r d r + + + align:start position:0% +r d r +equals and we we know this differential + + align:start position:0% +equals and we we know this differential + + + align:start position:0% +equals and we we know this differential +so I can just write it down but if you + + align:start position:0% +so I can just write it down but if you + + + align:start position:0% +so I can just write it down but if you +forgot it you can get it yourself + + align:start position:0% +forgot it you can get it yourself + + + align:start position:0% +forgot it you can get it yourself +right so um two oh sorry this is Dr + + align:start position:0% + + + + align:start position:0% + +is two x transpose DX + + align:start position:0% +is two x transpose DX + + + align:start position:0% +is two x transpose DX +right and so therefore + + align:start position:0% +right and so therefore + + + align:start position:0% +right and so therefore +Dr is equal to X transpose over RDX and + + align:start position:0% +Dr is equal to X transpose over RDX and + + + align:start position:0% +Dr is equal to X transpose over RDX and +then the gradient + + align:start position:0% +then the gradient + + + align:start position:0% +then the gradient +is the transpose of this which is X over + + align:start position:0% +is the transpose of this which is X over + + + align:start position:0% +is the transpose of this which is X over +r + + align:start position:0% +r + + + align:start position:0% +r +okay so no indices that that was kind of + + align:start position:0% +okay so no indices that that was kind of + + + align:start position:0% +okay so no indices that that was kind of +the trick here just to be able to do + + align:start position:0% +the trick here just to be able to do + + + align:start position:0% +the trick here just to be able to do +this sort of thing without any indices + + align:start position:0% +this sort of thing without any indices + + + align:start position:0% +this sort of thing without any indices +okay kind of like + + align:start position:0% +okay kind of like + + + align:start position:0% +okay kind of like +super powers for vectors and matrices to + + align:start position:0% +super powers for vectors and matrices to + + + align:start position:0% +super powers for vectors and matrices to +like I said this isn't hard + + align:start position:0% +like I said this isn't hard + + + align:start position:0% +like I said this isn't hard +what happens though is as things get a + + align:start position:0% +what happens though is as things get a + + + align:start position:0% +what happens though is as things get a +little more complicated have been good + + align:start position:0% +little more complicated have been good + + + align:start position:0% +little more complicated have been good +at this sort of the non-index approach + + align:start position:0% +at this sort of the non-index approach + + + align:start position:0% +at this sort of the non-index approach +gets more and more valuable + + align:start position:0% +gets more and more valuable + + + align:start position:0% +gets more and more valuable +okay so that's + + align:start position:0% +okay so that's + + + align:start position:0% +okay so that's +again there's no one right way to do it + + align:start position:0% +again there's no one right way to do it + + + align:start position:0% +again there's no one right way to do it +you could you could grind it through no + + align:start position:0% +you could you could grind it through no + + + align:start position:0% +you could you could grind it through no +matter how complicated I bet you all can + + align:start position:0% +matter how complicated I bet you all can + + + align:start position:0% +matter how complicated I bet you all can +do it but this is the fun way to do it + + align:start position:0% +do it but this is the fun way to do it + + + align:start position:0% +do it but this is the fun way to do it +all right lose this thing over here any + + align:start position:0% +all right lose this thing over here any + + + align:start position:0% +all right lose this thing over here any +questions about that + + align:start position:0% +questions about that + + + align:start position:0% +questions about that +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so I don't know if you've looked at the + + align:start position:0% +so I don't know if you've looked at the + + + align:start position:0% +so I don't know if you've looked at the +homework yet but uh the first problem + + align:start position:0% +homework yet but uh the first problem + + + align:start position:0% +homework yet but uh the first problem +has the transformations of the plane + + align:start position:0% +has the transformations of the plane + + + align:start position:0% +has the transformations of the plane +with the corgis and we're looking for + + align:start position:0% +with the corgis and we're looking for + + + align:start position:0% +with the corgis and we're looking for +two by two Jacobian matrices and in one + + align:start position:0% +two by two Jacobian matrices and in one + + + align:start position:0% +two by two Jacobian matrices and in one +case there's a there there's + + align:start position:0% +case there's a there there's + + + align:start position:0% +case there's a there there's +in in part D where there where where + + align:start position:0% +in in part D where there where where + + + align:start position:0% +in in part D where there where where +there's the warp there's a a matrix + + align:start position:0% +there's the warp there's a a matrix + + + align:start position:0% +there's the warp there's a a matrix +function of x + + align:start position:0% + + + + align:start position:0% + +that's multiplied by X + + align:start position:0% +that's multiplied by X + + + align:start position:0% +that's multiplied by X +right if the Matrix didn't depend on X + + align:start position:0% +right if the Matrix didn't depend on X + + + align:start position:0% +right if the Matrix didn't depend on X +the Jacobian would just be the Matrix + + align:start position:0% +the Jacobian would just be the Matrix + + + align:start position:0% +the Jacobian would just be the Matrix +right but because the Matrix depends on + + align:start position:0% +right but because the Matrix depends on + + + align:start position:0% +right but because the Matrix depends on +X there's going to be two terms right + + align:start position:0% +X there's going to be two terms right + + + align:start position:0% +X there's going to be two terms right +there's going to be + + align:start position:0% +there's going to be + + + align:start position:0% +there's going to be +roughly D Matrix + + align:start position:0% +roughly D Matrix + + + align:start position:0% +roughly D Matrix +of of x times X plus this is kind of the + + align:start position:0% +of of x times X plus this is kind of the + + + align:start position:0% +of of x times X plus this is kind of the +the template + + align:start position:0% +the template + + + align:start position:0% +the template +right and somehow a DX is going to come + + align:start position:0% +right and somehow a DX is going to come + + + align:start position:0% +right and somehow a DX is going to come +out of this term as well and so this + + align:start position:0% +out of this term as well and so this + + + align:start position:0% +out of this term as well and so this +term is the easy one that that would if + + align:start position:0% +term is the easy one that that would if + + + align:start position:0% +term is the easy one that that would if +if the Matrix is constant right and this + + align:start position:0% +if the Matrix is constant right and this + + + align:start position:0% +if the Matrix is constant right and this +one takes a little bit more work right + + align:start position:0% +one takes a little bit more work right + + + align:start position:0% +one takes a little bit more work right +so that's problem D on your homework in + + align:start position:0% +so that's problem D on your homework in + + + align:start position:0% +so that's problem D on your homework in +the first part + + align:start position:0% +the first part + + + align:start position:0% +the first part +all right good + + align:start position:0% + + + + align:start position:0% + +um okay well then I'm going to go back + + align:start position:0% +um okay well then I'm going to go back + + + align:start position:0% +um okay well then I'm going to go back +and do what I was starting to do + + align:start position:0% +and do what I was starting to do + + + align:start position:0% +and do what I was starting to do +less time and I think it just makes + + align:start position:0% +less time and I think it just makes + + + align:start position:0% +less time and I think it just makes +sense to go back to the beginning since + + align:start position:0% +sense to go back to the beginning since + + + align:start position:0% +sense to go back to the beginning since +we've had a whole weekend since + + align:start position:0% +we've had a whole weekend since + + + align:start position:0% +we've had a whole weekend since +last time okay and so uh Matrix Jacobian + + align:start position:0% +last time okay and so uh Matrix Jacobian + + + align:start position:0% +last time okay and so uh Matrix Jacobian +so in this this this Julia notebook here + + align:start position:0% +so in this this this Julia notebook here + + + align:start position:0% +so in this this this Julia notebook here +and by the way if anybody has questions + + align:start position:0% +and by the way if anybody has questions + + + align:start position:0% +and by the way if anybody has questions +about Julia if you feel free to ask + + align:start position:0% +about Julia if you feel free to ask + + + align:start position:0% +about Julia if you feel free to ask +about that as well but the the goal here + + align:start position:0% +about that as well but the the goal here + + + align:start position:0% +about that as well but the the goal here +this is a this Blackboard example is a + + align:start position:0% +this is a this Blackboard example is a + + + align:start position:0% +this is a this Blackboard example is a +scalar function of a vector + + align:start position:0% +scalar function of a vector + + + align:start position:0% +scalar function of a vector +and I'm really excited about functions + + align:start position:0% +and I'm really excited about functions + + + align:start position:0% +and I'm really excited about functions +where the input and output are actually + + align:start position:0% +where the input and output are actually + + + align:start position:0% +where the input and output are actually +matrices themselves right so you know + + align:start position:0% +matrices themselves right so you know + + + align:start position:0% +matrices themselves right so you know +Matrix Square Matrix inverse we've seen + + align:start position:0% +Matrix Square Matrix inverse we've seen + + + align:start position:0% +Matrix Square Matrix inverse we've seen +Matrix Cube I like to think of the Lu + + align:start position:0% +Matrix Cube I like to think of the Lu + + + align:start position:0% +Matrix Cube I like to think of the Lu +decomposition as a as a function of + + align:start position:0% +decomposition as a as a function of + + + align:start position:0% +decomposition as a as a function of +matrices I don't know if you've ever + + align:start position:0% +matrices I don't know if you've ever + + + align:start position:0% +matrices I don't know if you've ever +thought about it but the Lu + + align:start position:0% +thought about it but the Lu + + + align:start position:0% +thought about it but the Lu +decomposition or even the eigen Dig + + align:start position:0% +decomposition or even the eigen Dig + + + align:start position:0% +decomposition or even the eigen Dig +composition of a matrix is is a function + + align:start position:0% +composition of a matrix is is a function + + + align:start position:0% +composition of a matrix is is a function +from matrices to + + align:start position:0% +from matrices to + + + align:start position:0% +from matrices to +pieces of matrices in effect + + align:start position:0% +pieces of matrices in effect + + + align:start position:0% +pieces of matrices in effect +so uh we'll we'll see how that goes + + align:start position:0% +so uh we'll we'll see how that goes + + + align:start position:0% +so uh we'll we'll see how that goes +through all right so + + align:start position:0% +through all right so + + + align:start position:0% +through all right so +let me + + align:start position:0% +let me + + + align:start position:0% +let me +go back to the beginning here just very + + align:start position:0% +go back to the beginning here just very + + + align:start position:0% +go back to the beginning here just very +quickly we're using Julia's symbolics + + align:start position:0% +quickly we're using Julia's symbolics + + + align:start position:0% +quickly we're using Julia's symbolics +which is kind of fun to do + + align:start position:0% +which is kind of fun to do + + + align:start position:0% +which is kind of fun to do +okay and this shows up later I don't + + align:start position:0% +okay and this shows up later I don't + + + align:start position:0% +okay and this shows up later I don't +know why it's at the beginning so we'll + + align:start position:0% +know why it's at the beginning so we'll + + + align:start position:0% +know why it's at the beginning so we'll +just get right past it but here's the + + align:start position:0% +just get right past it but here's the + + + align:start position:0% +just get right past it but here's the +Matrix that will work with a lot this is + + align:start position:0% +Matrix that will work with a lot this is + + + align:start position:0% +Matrix that will work with a lot this is +the symbolic Matrix that has pqrs going + + align:start position:0% +the symbolic Matrix that has pqrs going + + + align:start position:0% +the symbolic Matrix that has pqrs going +in the column major order + + align:start position:0% +in the column major order + + + align:start position:0% +in the column major order +okay and so I just declared PQ and R and + + align:start position:0% +okay and so I just declared PQ and R and + + + align:start position:0% +okay and so I just declared PQ and R and +S to be variables as well as Theta so + + align:start position:0% +S to be variables as well as Theta so + + + align:start position:0% +S to be variables as well as Theta so +Julia lets me put them in as elements of + + align:start position:0% +Julia lets me put them in as elements of + + + align:start position:0% +Julia lets me put them in as elements of +matrices okay so simple thing and last + + align:start position:0% +matrices okay so simple thing and last + + + align:start position:0% +matrices okay so simple thing and last +time I introduced the VEC command which + + align:start position:0% +time I introduced the VEC command which + + + align:start position:0% +time I introduced the VEC command which +basically squashes a two by two Matrix + + align:start position:0% +basically squashes a two by two Matrix + + + align:start position:0% +basically squashes a two by two Matrix +or any in fact any Matrix down to a + + align:start position:0% +or any in fact any Matrix down to a + + + align:start position:0% +or any in fact any Matrix down to a +vector it's just all you do with VEC in + + align:start position:0% +vector it's just all you do with VEC in + + + align:start position:0% +vector it's just all you do with VEC in +case you missed it last time is you take + + align:start position:0% +case you missed it last time is you take + + + align:start position:0% +case you missed it last time is you take +the First Column and stack it on the + + align:start position:0% +the First Column and stack it on the + + + align:start position:0% +the First Column and stack it on the +second column stack it on the third + + align:start position:0% +second column stack it on the third + + + align:start position:0% +second column stack it on the third +column and so forth okay and this is + + align:start position:0% +column and so forth okay and this is + + + align:start position:0% +column and so forth okay and this is +again + + align:start position:0% +again + + + align:start position:0% +again +what we show students because it's + + align:start position:0% +what we show students because it's + + + align:start position:0% +what we show students because it's +concrete + + align:start position:0% +concrete + + + align:start position:0% +concrete +but as far as I can tell you never + + align:start position:0% +but as far as I can tell you never + + + align:start position:0% +but as far as I can tell you never +really need to vect things other than + + align:start position:0% +really need to vect things other than + + + align:start position:0% +really need to vect things other than +maybe in your mind right but I mean it + + align:start position:0% +maybe in your mind right but I mean it + + + align:start position:0% +maybe in your mind right but I mean it +it's another one of these Comfort things + + align:start position:0% +it's another one of these Comfort things + + + align:start position:0% +it's another one of these Comfort things +that I don't think you really have to do + + align:start position:0% +that I don't think you really have to do + + + align:start position:0% +that I don't think you really have to do +in practice okay but it does have a way + + align:start position:0% +in practice okay but it does have a way + + + align:start position:0% +in practice okay but it does have a way +of of of allowing you to use one + + align:start position:0% +of of of allowing you to use one + + + align:start position:0% +of of of allowing you to use one +notation for many many things so there's + + align:start position:0% +notation for many many things so there's + + + align:start position:0% +notation for many many things so there's +the vet command it just squashes a + + align:start position:0% +the vet command it just squashes a + + + align:start position:0% +the vet command it just squashes a +matrix okay and + + align:start position:0% +matrix okay and + + + align:start position:0% +matrix okay and +and here's the Matrix square of a two by + + align:start position:0% +and here's the Matrix square of a two by + + + align:start position:0% +and here's the Matrix square of a two by +two Matrix all of you can do this just + + align:start position:0% +two Matrix all of you can do this just + + + align:start position:0% +two Matrix all of you can do this just +take that pqrs Matrix and do that dot + + align:start position:0% +take that pqrs Matrix and do that dot + + + align:start position:0% +take that pqrs Matrix and do that dot +product the thing and you get the Matrix + + align:start position:0% +product the thing and you get the Matrix + + + align:start position:0% +product the thing and you get the Matrix +Square which we convex + + align:start position:0% +Square which we convex + + + align:start position:0% +Square which we convex +right and maybe I'll make this just a + + align:start position:0% +right and maybe I'll make this just a + + + align:start position:0% +right and maybe I'll make this just a +little bit smaller so it can get a + + align:start position:0% +little bit smaller so it can get a + + + align:start position:0% +little bit smaller so it can get a +little more real estate + + align:start position:0% +little more real estate + + + align:start position:0% +little more real estate +yeah so uh okay good + + align:start position:0% +yeah so uh okay good + + + align:start position:0% +yeah so uh okay good +so this this is this is the VEC of the + + align:start position:0% +so this this is this is the VEC of the + + + align:start position:0% +so this this is this is the VEC of the +The Matrix square and so uh one way to + + align:start position:0% +The Matrix square and so uh one way to + + + align:start position:0% +The Matrix square and so uh one way to +think of Matrix square is a function + + align:start position:0% +think of Matrix square is a function + + + align:start position:0% +think of Matrix square is a function +from R4 to R4 it's the input of the + + align:start position:0% +from R4 to R4 it's the input of the + + + align:start position:0% +from R4 to R4 it's the input of the +variables P Q R and S and the output are + + align:start position:0% +variables P Q R and S and the output are + + + align:start position:0% +variables P Q R and S and the output are +these four functions of pqr and S you + + align:start position:0% +these four functions of pqr and S you + + + align:start position:0% +these four functions of pqr and S you +know p squared plus q r all the way down + + align:start position:0% +know p squared plus q r all the way down + + + align:start position:0% +know p squared plus q r all the way down +to q r plus s squared + + align:start position:0% +to q r plus s squared + + + align:start position:0% +to q r plus s squared +right so that that's a function that + + align:start position:0% +right so that that's a function that + + + align:start position:0% +right so that that's a function that +takes R4 to R4 but really we all know + + align:start position:0% +takes R4 to R4 but really we all know + + + align:start position:0% +takes R4 to R4 but really we all know +it's a function from two by two matrices + + align:start position:0% +it's a function from two by two matrices + + + align:start position:0% +it's a function from two by two matrices +to two by two matrices right R4 tar4 is + + align:start position:0% +to two by two matrices right R4 tar4 is + + + align:start position:0% +to two by two matrices right R4 tar4 is +just a crutch right it's really two by + + align:start position:0% +just a crutch right it's really two by + + + align:start position:0% +just a crutch right it's really two by +two matrices to two by two matrices + + align:start position:0% +two matrices to two by two matrices + + + align:start position:0% +two matrices to two by two matrices +okay and so we can calculate the + + align:start position:0% +okay and so we can calculate the + + + align:start position:0% +okay and so we can calculate the +Jacobian of this thing + + align:start position:0% +Jacobian of this thing + + + align:start position:0% +Jacobian of this thing +okay and I'll just remind you that the + + align:start position:0% +okay and I'll just remind you that the + + + align:start position:0% +okay and I'll just remind you that the +Jacobian is nothing other than all the + + align:start position:0% +Jacobian is nothing other than all the + + + align:start position:0% +Jacobian is nothing other than all the +derivatives of each of these four + + align:start position:0% +derivatives of each of these four + + + align:start position:0% +derivatives of each of these four +expressions with respect to all of the + + align:start position:0% +expressions with respect to all of the + + + align:start position:0% +expressions with respect to all of the +four input variables P Q R and S right + + align:start position:0% +four input variables P Q R and S right + + + align:start position:0% +four input variables P Q R and S right +so so this output p squared plus QR + + align:start position:0% +so so this output p squared plus QR + + + align:start position:0% +so so this output p squared plus QR +belongs to the first row and we'll take + + align:start position:0% +belongs to the first row and we'll take + + + align:start position:0% +belongs to the first row and we'll take +the derivative respect to p and then q + + align:start position:0% +the derivative respect to p and then q + + + align:start position:0% +the derivative respect to p and then q +and then R and then s and if you do that + + align:start position:0% +and then R and then s and if you do that + + + align:start position:0% +and then R and then s and if you do that +you'll get this first row okay and so + + align:start position:0% +you'll get this first row okay and so + + + align:start position:0% +you'll get this first row okay and so +forth so the the inputs the are the + + align:start position:0% +forth so the the inputs the are the + + + align:start position:0% +forth so the the inputs the are the +columns the outputs are the rows okay + + align:start position:0% +columns the outputs are the rows okay + + + align:start position:0% +columns the outputs are the rows okay +and that's the Jacobian matrix okay and + + align:start position:0% +and that's the Jacobian matrix okay and + + + align:start position:0% +and that's the Jacobian matrix okay and +Julia's happy to compute it for you but + + align:start position:0% +Julia's happy to compute it for you but + + + align:start position:0% +Julia's happy to compute it for you but +you could have all done this yourself as + + align:start position:0% +you could have all done this yourself as + + + align:start position:0% +you could have all done this yourself as +well okay so there's the Jacobian and + + align:start position:0% +well okay so there's the Jacobian and + + + align:start position:0% +well okay so there's the Jacobian and +our goal + + align:start position:0% +our goal + + + align:start position:0% +our goal +is to our goal is really to find the + + align:start position:0% +is to our goal is really to find the + + + align:start position:0% +is to our goal is really to find the +notation that lets you write this Matrix + + align:start position:0% +notation that lets you write this Matrix + + + align:start position:0% +notation that lets you write this Matrix +without writing the Matrix that's what + + align:start position:0% +without writing the Matrix that's what + + + align:start position:0% +without writing the Matrix that's what +we're trying to do here we'd like to + + align:start position:0% +we're trying to do here we'd like to + + + align:start position:0% +we're trying to do here we'd like to +write this Matrix but without writing + + align:start position:0% +write this Matrix but without writing + + + align:start position:0% +write this Matrix but without writing +the Matrix that's what we're heading for + + align:start position:0% +the Matrix that's what we're heading for + + + align:start position:0% +the Matrix that's what we're heading for +okay but + + align:start position:0% +okay but + + + align:start position:0% +okay but +I love to check things over I like to do + + align:start position:0% +I love to check things over I like to do + + + align:start position:0% +I love to check things over I like to do +things with symbols if I can I like to + + align:start position:0% +things with symbols if I can I like to + + + align:start position:0% +things with symbols if I can I like to +do things with numbers if I can it makes + + align:start position:0% +do things with numbers if I can it makes + + + align:start position:0% +do things with numbers if I can it makes +me happy when things come out equal so + + align:start position:0% +me happy when things come out equal so + + + align:start position:0% +me happy when things come out equal so +let's do this numerically right so + + align:start position:0% +let's do this numerically right so + + + align:start position:0% +let's do this numerically right so +here's my inputs are going to be one two + + align:start position:0% +here's my inputs are going to be one two + + + align:start position:0% +here's my inputs are going to be one two +three four + + align:start position:0% +three four + + + align:start position:0% +three four +okay and the + + align:start position:0% +okay and the + + + align:start position:0% +okay and the +I'm going to make some perturbations of + + align:start position:0% +I'm going to make some perturbations of + + + align:start position:0% +I'm going to make some perturbations of +the one two three four by just taking + + align:start position:0% +the one two three four by just taking + + + align:start position:0% +the one two three four by just taking +one two three four divided by ten + + align:start position:0% +one two three four divided by ten + + + align:start position:0% +one two three four divided by ten +thousand and I'm going to put into this + + align:start position:0% +thousand and I'm going to put into this + + + align:start position:0% +thousand and I'm going to put into this +Jacobian I'm just going to put in these + + align:start position:0% +Jacobian I'm just going to put in these + + + align:start position:0% +Jacobian I'm just going to put in these +numbers this Jacobian so this is the + + align:start position:0% +numbers this Jacobian so this is the + + + align:start position:0% +numbers this Jacobian so this is the +this is the this is the Jacobian of the + + align:start position:0% +this is the this is the Jacobian of the + + + align:start position:0% +this is the this is the Jacobian of the +square function at the Matrix one two + + align:start position:0% +square function at the Matrix one two + + + align:start position:0% +square function at the Matrix one two +three four right so if I perturb The + + align:start position:0% +three four right so if I perturb The + + + align:start position:0% +three four right so if I perturb The +Matrix a little bit like this e here I + + align:start position:0% +Matrix a little bit like this e here I + + + align:start position:0% +Matrix a little bit like this e here I +should know how the Matrix perturbs + + align:start position:0% +should know how the Matrix perturbs + + + align:start position:0% +should know how the Matrix perturbs +okay and and so all I should have to do + + align:start position:0% +okay and and so all I should have to do + + + align:start position:0% +okay and and so all I should have to do +is take this Jacobian which is + + align:start position:0% +is take this Jacobian which is + + + align:start position:0% +is take this Jacobian which is +this this is the same expression as here + + align:start position:0% +this this is the same expression as here + + + align:start position:0% +this this is the same expression as here +and multiply that by the VEC of my + + align:start position:0% +and multiply that by the VEC of my + + + align:start position:0% +and multiply that by the VEC of my +perturbation okay and uh of course here + + align:start position:0% +perturbation okay and uh of course here + + + align:start position:0% +perturbation okay and uh of course here +here's what we get as the answer and we + + align:start position:0% +here's what we get as the answer and we + + + align:start position:0% +here's what we get as the answer and we +can check that with by just doing a + + align:start position:0% +can check that with by just doing a + + + align:start position:0% +can check that with by just doing a +finite difference with the matrices and + + align:start position:0% +finite difference with the matrices and + + + align:start position:0% +finite difference with the matrices and +you could see the first order it just + + align:start position:0% +you could see the first order it just + + + align:start position:0% +you could see the first order it just +works okay so when I see this I'm happy + + align:start position:0% +works okay so when I see this I'm happy + + + align:start position:0% +works okay so when I see this I'm happy +all right other people trust mathematics + + align:start position:0% +all right other people trust mathematics + + + align:start position:0% +all right other people trust mathematics +me I make too many errors I gotta I have + + align:start position:0% +me I make too many errors I gotta I have + + + align:start position:0% +me I make too many errors I gotta I have +to double check it and you know just + + align:start position:0% +to double check it and you know just + + + align:start position:0% +to double check it and you know just +just to see these numbers you know this + + align:start position:0% +just to see these numbers you know this + + + align:start position:0% +just to see these numbers you know this +0.0014 and the 0030 and the + + align:start position:0% +0.0014 and the 0030 and the + + + align:start position:0% +0.0014 and the 0030 and the +0020 and the 0044 just matching up with + + align:start position:0% +0020 and the 0044 just matching up with + + + align:start position:0% +0020 and the 0044 just matching up with +the numbers above again this is just the + + align:start position:0% +the numbers above again this is just the + + + align:start position:0% +the numbers above again this is just the +finite differences this is what the + + align:start position:0% +finite differences this is what the + + + align:start position:0% +finite differences this is what the +theory tells you right and it I don't + + align:start position:0% +theory tells you right and it I don't + + + align:start position:0% +theory tells you right and it I don't +know if you guys need to check your work + + align:start position:0% +know if you guys need to check your work + + + align:start position:0% +know if you guys need to check your work +but I love checking my work invariably I + + align:start position:0% +but I love checking my work invariably I + + + align:start position:0% +but I love checking my work invariably I +lose factors of 2 where pi + + align:start position:0% +lose factors of 2 where pi + + + align:start position:0% +lose factors of 2 where pi +so this is the best way to find them + + align:start position:0% +so this is the best way to find them + + + align:start position:0% +so this is the best way to find them +Okay so + + align:start position:0% +Okay so + + + align:start position:0% +Okay so +so uh uh so so so + + align:start position:0% +so uh uh so so so + + + align:start position:0% +so uh uh so so so +rather than vexing and flattening + + align:start position:0% +rather than vexing and flattening + + + align:start position:0% +rather than vexing and flattening +another way to basically uh to basically + + align:start position:0% +another way to basically uh to basically + + + align:start position:0% +another way to basically uh to basically +Express the Jacobian of a square and + + align:start position:0% +Express the Jacobian of a square and + + + align:start position:0% +Express the Jacobian of a square and +you'll see why it works in a minute is + + align:start position:0% +you'll see why it works in a minute is + + + align:start position:0% +you'll see why it works in a minute is +to express it as a linear transformation + + align:start position:0% +to express it as a linear transformation + + + align:start position:0% +to express it as a linear transformation +okay and one of the things that if it + + align:start position:0% +okay and one of the things that if it + + + align:start position:0% +okay and one of the things that if it +didn't if you weren't if you weren't hit + + align:start position:0% +didn't if you weren't if you weren't hit + + + align:start position:0% +didn't if you weren't if you weren't hit +with this with your linear algebra class + + align:start position:0% +with this with your linear algebra class + + + align:start position:0% +with this with your linear algebra class +when you first took linear algebra then + + align:start position:0% +when you first took linear algebra then + + + align:start position:0% +when you first took linear algebra then +this is a good time to recognize that + + align:start position:0% +this is a good time to recognize that + + + align:start position:0% +this is a good time to recognize that +being you know + + align:start position:0% +being you know + + + align:start position:0% +being you know +being able to write down a linear + + align:start position:0% +being able to write down a linear + + + align:start position:0% +being able to write down a linear +transformation doesn't mean you have to + + align:start position:0% +transformation doesn't mean you have to + + + align:start position:0% +transformation doesn't mean you have to +write down a matrix right you could + + align:start position:0% +write down a matrix right you could + + + align:start position:0% +write down a matrix right you could +write down linear Transformations + + align:start position:0% +write down linear Transformations + + + align:start position:0% +write down linear Transformations +without writing down a matrix for + + align:start position:0% +without writing down a matrix for + + + align:start position:0% +without writing down a matrix for +example uh you think of M as a constant + + align:start position:0% +example uh you think of M as a constant + + + align:start position:0% +example uh you think of M as a constant +here + + align:start position:0% +here + + + align:start position:0% +here +right so m is going to be our position + + align:start position:0% +right so m is going to be our position + + + align:start position:0% +right so m is going to be our position +where we're taking derivative or + + align:start position:0% +where we're taking derivative or + + + align:start position:0% +where we're taking derivative or +whatever it is it's a constant okay and + + align:start position:0% +whatever it is it's a constant okay and + + + align:start position:0% +whatever it is it's a constant okay and +I just want to point out that this is a + + align:start position:0% +I just want to point out that this is a + + + align:start position:0% +I just want to point out that this is a +linear transformation of matrices right + + align:start position:0% +linear transformation of matrices right + + + align:start position:0% +linear transformation of matrices right +so if m is a two by two Matrix and e is + + align:start position:0% +so if m is a two by two Matrix and e is + + + align:start position:0% +so if m is a two by two Matrix and e is +a two by two Matrix + + align:start position:0% +a two by two Matrix + + + align:start position:0% +a two by two Matrix +uh this expression without writing down + + align:start position:0% +uh this expression without writing down + + + align:start position:0% +uh this expression without writing down +the Matrix is a linear transformation + + align:start position:0% +the Matrix is a linear transformation + + + align:start position:0% +the Matrix is a linear transformation +what do you have to check if it's a + + align:start position:0% +what do you have to check if it's a + + + align:start position:0% +what do you have to check if it's a +linear transformation well let's see if + + align:start position:0% +linear transformation well let's see if + + + align:start position:0% +linear transformation well let's see if +I multiply e by a number like 2 or Pi + + align:start position:0% +I multiply e by a number like 2 or Pi + + + align:start position:0% +I multiply e by a number like 2 or Pi +does the output get multiplied by by the + + align:start position:0% +does the output get multiplied by by the + + + align:start position:0% +does the output get multiplied by by the +same number like 2 or Pi yep the scalar + + align:start position:0% +same number like 2 or Pi yep the scalar + + + align:start position:0% +same number like 2 or Pi yep the scalar +would pull right out and if I input E1 + + align:start position:0% +would pull right out and if I input E1 + + + align:start position:0% +would pull right out and if I input E1 +plus E2 with the output be the output of + + align:start position:0% +plus E2 with the output be the output of + + + align:start position:0% +plus E2 with the output be the output of +the 1 plus the output of the two right + + align:start position:0% +the 1 plus the output of the two right + + + align:start position:0% +the 1 plus the output of the two right +you know you check those two things and + + align:start position:0% +you know you check those two things and + + + align:start position:0% +you know you check those two things and +that's what you need to check that the + + align:start position:0% +that's what you need to check that the + + + align:start position:0% +that's what you need to check that the +function is linear you don't need a + + align:start position:0% +function is linear you don't need a + + + align:start position:0% +function is linear you don't need a +matrix right okay matrices are very + + align:start position:0% +matrix right okay matrices are very + + + align:start position:0% +matrix right okay matrices are very +concrete but you don't need them when + + align:start position:0% +concrete but you don't need them when + + + align:start position:0% +concrete but you don't need them when +you're grown up right so this is a + + align:start position:0% +you're grown up right so this is a + + + align:start position:0% +you're grown up right so this is a +linear transformation on E + + align:start position:0% +linear transformation on E + + + align:start position:0% +linear transformation on E +okay and it's going to turn out to be + + align:start position:0% +okay and it's going to turn out to be + + + align:start position:0% +okay and it's going to turn out to be +exactly the right linear transformation + + align:start position:0% +exactly the right linear transformation + + + align:start position:0% +exactly the right linear transformation +for the very Matrix we have at hand and + + align:start position:0% +for the very Matrix we have at hand and + + + align:start position:0% +for the very Matrix we have at hand and +so with M being the Matrix one two three + + align:start position:0% +so with M being the Matrix one two three + + + align:start position:0% +so with M being the Matrix one two three +four and E here let's remind you what + + align:start position:0% +four and E here let's remind you what + + + align:start position:0% +four and E here let's remind you what +these matrices are if you've already + + align:start position:0% +these matrices are if you've already + + + align:start position:0% +these matrices are if you've already +forgotten but if m is the Matrix one two + + align:start position:0% +forgotten but if m is the Matrix one two + + + align:start position:0% +forgotten but if m is the Matrix one two +three four and E is the perturbation + + align:start position:0% +three four and E is the perturbation + + + align:start position:0% +three four and E is the perturbation +Matrix + + align:start position:0% +Matrix + + + align:start position:0% +Matrix +the same numbers divided by ten thousand + + align:start position:0% +the same numbers divided by ten thousand + + + align:start position:0% +the same numbers divided by ten thousand +this linear transformation applied to e + + align:start position:0% +this linear transformation applied to e + + + align:start position:0% +this linear transformation applied to e +gives you the derivative without right + + align:start position:0% +gives you the derivative without right + + + align:start position:0% +gives you the derivative without right +somehow the information in here is the + + align:start position:0% +somehow the information in here is the + + + align:start position:0% +somehow the information in here is the +same as the information of the Jacobian + + align:start position:0% +same as the information of the Jacobian + + + align:start position:0% +same as the information of the Jacobian +and yet I never formed the Jacobian okay + + align:start position:0% +and yet I never formed the Jacobian okay + + + align:start position:0% +and yet I never formed the Jacobian okay +that's a key key Point never form the + + align:start position:0% +that's a key key Point never form the + + + align:start position:0% +that's a key key Point never form the +Jacobian but the information of get to + + align:start position:0% +Jacobian but the information of get to + + + align:start position:0% +Jacobian but the information of get to +get the answer is embodied in this + + align:start position:0% +get the answer is embodied in this + + + align:start position:0% +get the answer is embodied in this +expression + + align:start position:0% +expression + + + align:start position:0% +expression +right so who needs who needs to build + + align:start position:0% +right so who needs who needs to build + + + align:start position:0% +right so who needs who needs to build +the 4x4 Matrix if you can just have this + + align:start position:0% +the 4x4 Matrix if you can just have this + + + align:start position:0% +the 4x4 Matrix if you can just have this +expression questions + + align:start position:0% +expression questions + + + align:start position:0% +expression questions +anything does it make sense doesn't make + + align:start position:0% +anything does it make sense doesn't make + + + align:start position:0% +anything does it make sense doesn't make +sense + + align:start position:0% +sense + + + align:start position:0% +sense +you want to see why that works + + align:start position:0% +you want to see why that works + + + align:start position:0% +you want to see why that works +all right so I find the chronicle + + align:start position:0% +all right so I find the chronicle + + + align:start position:0% +all right so I find the chronicle +product notation is a good way to kind + + align:start position:0% +product notation is a good way to kind + + + align:start position:0% +product notation is a good way to kind +of to sort of be ready to to set the + + align:start position:0% +of to sort of be ready to to set the + + + align:start position:0% +of to sort of be ready to to set the +sort of thing up right and so let me + + align:start position:0% +sort of thing up right and so let me + + + align:start position:0% +sort of thing up right and so let me +tell you about the chronicle product + + align:start position:0% +tell you about the chronicle product + + + align:start position:0% +tell you about the chronicle product +notation and I'm going to set up these + + align:start position:0% +notation and I'm going to set up these + + + align:start position:0% +notation and I'm going to set up these +variables a b c and d okay and here's + + align:start position:0% +variables a b c and d okay and here's + + + align:start position:0% +variables a b c and d okay and here's +just a pair of matrices + + align:start position:0% +just a pair of matrices + + + align:start position:0% +just a pair of matrices +okay and what I want you to notice is + + align:start position:0% +okay and what I want you to notice is + + + align:start position:0% +okay and what I want you to notice is +that we have oh am I sharing my screen + + align:start position:0% +that we have oh am I sharing my screen + + + align:start position:0% +that we have oh am I sharing my screen +just occurred to me that I'm not even + + align:start position:0% +just occurred to me that I'm not even + + + align:start position:0% +just occurred to me that I'm not even +sure I'm sharing my screen + + align:start position:0% +sure I'm sharing my screen + + + align:start position:0% +sure I'm sharing my screen +yeah sorry about that + + align:start position:0% +yeah sorry about that + + + align:start position:0% +yeah sorry about that +just hit me that you don't see what I'm + + align:start position:0% +just hit me that you don't see what I'm + + + align:start position:0% +just hit me that you don't see what I'm +doing + + align:start position:0% +doing + + + align:start position:0% +doing +all right there we go + + align:start position:0% +all right there we go + + + align:start position:0% +all right there we go +and the reason I realized that is + + align:start position:0% +and the reason I realized that is + + + align:start position:0% +and the reason I realized that is +because I wanted to use this pen here + + align:start position:0% +because I wanted to use this pen here + + + align:start position:0% +because I wanted to use this pen here +anyway so uh so I want everybody to see + + align:start position:0% +anyway so uh so I want everybody to see + + + align:start position:0% +anyway so uh so I want everybody to see +the top half versus the bottom half of + + align:start position:0% +the top half versus the bottom half of + + + align:start position:0% +the top half versus the bottom half of +this Matrix right so uh here what I'm + + align:start position:0% +this Matrix right so uh here what I'm + + + align:start position:0% +this Matrix right so uh here what I'm +doing is I'm taking the chronicle + + align:start position:0% +doing is I'm taking the chronicle + + + align:start position:0% +doing is I'm taking the chronicle +product + + align:start position:0% +product + + + align:start position:0% +product +of this two by one Matrix + + align:start position:0% +of this two by one Matrix + + + align:start position:0% +of this two by one Matrix +Chron occur the + + align:start position:0% +Chron occur the + + + align:start position:0% +Chron occur the +let's see if I can do this it's hard to + + align:start position:0% +let's see if I can do this it's hard to + + + align:start position:0% +let's see if I can do this it's hard to +I'm using just the mouse + + align:start position:0% +I'm using just the mouse + + + align:start position:0% +I'm using just the mouse +so P Q R and S is this coming out on the + + align:start position:0% +so P Q R and S is this coming out on the + + + align:start position:0% +so P Q R and S is this coming out on the +screen can you see the green + + align:start position:0% +screen can you see the green + + + align:start position:0% +screen can you see the green +so P Q R and S and I just want you to + + align:start position:0% +so P Q R and S and I just want you to + + + align:start position:0% +so P Q R and S and I just want you to +see + + align:start position:0% +see + + + align:start position:0% +see +yes + + align:start position:0% +yes + + + align:start position:0% +yes +whoops + + align:start position:0% +whoops + + + align:start position:0% +whoops +it's not doing it now + + align:start position:0% +it's not doing it now + + + align:start position:0% +it's not doing it now +but + + align:start position:0% + + + + align:start position:0% + +there we go + + align:start position:0% +there we go + + + align:start position:0% +there we go +okay so I want you all to see that + + align:start position:0% +okay so I want you all to see that + + + align:start position:0% +okay so I want you all to see that +that it's taking the the whole second + + align:start position:0% +that it's taking the the whole second + + + align:start position:0% +that it's taking the the whole second +Matrix pqrs and multiplying it by a on + + align:start position:0% +Matrix pqrs and multiplying it by a on + + + align:start position:0% +Matrix pqrs and multiplying it by a on +top and it's oh and then this is taking + + align:start position:0% +top and it's oh and then this is taking + + + align:start position:0% +top and it's oh and then this is taking +the whole second Matrix pqrs and + + align:start position:0% +the whole second Matrix pqrs and + + + align:start position:0% +the whole second Matrix pqrs and +multiplying by B on the bottom right and + + align:start position:0% +multiplying by B on the bottom right and + + + align:start position:0% +multiplying by B on the bottom right and +so what it does is in effect it takes + + align:start position:0% +so what it does is in effect it takes + + + align:start position:0% +so what it does is in effect it takes +you'll see that every possible product + + align:start position:0% +you'll see that every possible product + + + align:start position:0% +you'll see that every possible product +of something over here on the left and + + align:start position:0% +of something over here on the left and + + + align:start position:0% +of something over here on the left and +something over here on the right shows + + align:start position:0% +something over here on the right shows + + + align:start position:0% +something over here on the right shows +up and it shows up in a very consistent + + align:start position:0% +up and it shows up in a very consistent + + + align:start position:0% +up and it shows up in a very consistent +order once you see a couple more + + align:start position:0% +order once you see a couple more + + + align:start position:0% +order once you see a couple more +examples you'll see how the pattern goes + + align:start position:0% +examples you'll see how the pattern goes + + + align:start position:0% +examples you'll see how the pattern goes +so this is the chronicle product so + + align:start position:0% +so this is the chronicle product so + + + align:start position:0% +so this is the chronicle product so +let's see so + + align:start position:0% +let's see so + + + align:start position:0% +let's see so +um + + align:start position:0% +um + + + align:start position:0% +um +so here's an example where we take a + + align:start position:0% +so here's an example where we take a + + + align:start position:0% +so here's an example where we take a +ABCD with pqrs and I'm sure you can all + + align:start position:0% +ABCD with pqrs and I'm sure you can all + + + align:start position:0% +ABCD with pqrs and I'm sure you can all +see that there's a pqrs times the a pqrs + + align:start position:0% +see that there's a pqrs times the a pqrs + + + align:start position:0% +see that there's a pqrs times the a pqrs +now in the bottom left times the b in + + align:start position:0% +now in the bottom left times the b in + + + align:start position:0% +now in the bottom left times the b in +the upper right the pqrs is times the C + + align:start position:0% +the upper right the pqrs is times the C + + + align:start position:0% +the upper right the pqrs is times the C +and times the D right so the the pattern + + align:start position:0% +and times the D right so the the pattern + + + align:start position:0% +and times the D right so the the pattern +is one way to look at it is you take + + align:start position:0% +is one way to look at it is you take + + + align:start position:0% +is one way to look at it is you take +every element on the left and uh + + align:start position:0% +every element on the left and uh + + + align:start position:0% +every element on the left and uh +multiply it by the entire Matrix on the + + align:start position:0% +multiply it by the entire Matrix on the + + + align:start position:0% +multiply it by the entire Matrix on the +right and then put it in the same order + + align:start position:0% +right and then put it in the same order + + + align:start position:0% +right and then put it in the same order +right and so sometimes it's easier to + + align:start position:0% +right and so sometimes it's easier to + + + align:start position:0% +right and so sometimes it's easier to +see it with with these sort of pictures + + align:start position:0% +see it with with these sort of pictures + + + align:start position:0% +see it with with these sort of pictures +and so here what we have is this two by + + align:start position:0% +and so here what we have is this two by + + + align:start position:0% +and so here what we have is this two by +two two by three Matrix which is a b c d + + align:start position:0% +two two by three Matrix which is a b c d + + + align:start position:0% +two two by three Matrix which is a b c d +e e f so I can + + align:start position:0% +e e f so I can + + + align:start position:0% +e e f so I can +put it over here if you want to see it + + align:start position:0% +put it over here if you want to see it + + + align:start position:0% +put it over here if you want to see it +so I'm taking the chronicle product of a + + align:start position:0% +so I'm taking the chronicle product of a + + + align:start position:0% +so I'm taking the chronicle product of a +b c d e f this way + + align:start position:0% +b c d e f this way + + + align:start position:0% +b c d e f this way +and I'm taking the chronicle product + + align:start position:0% +and I'm taking the chronicle product + + + align:start position:0% +and I'm taking the chronicle product +with + + align:start position:0% +with + + + align:start position:0% +with +uh there's the pizza + + align:start position:0% +uh there's the pizza + + + align:start position:0% +uh there's the pizza +what do we have the alien + + align:start position:0% + + + + align:start position:0% + +the pizza the alien uh the smiley cat + + align:start position:0% +the pizza the alien uh the smiley cat + + + align:start position:0% +the pizza the alien uh the smiley cat +and what do we have here the panda + + align:start position:0% + + + + align:start position:0% + +right so uh you know Julia is perfectly + + align:start position:0% +right so uh you know Julia is perfectly + + + align:start position:0% +right so uh you know Julia is perfectly +comfortable with doing that sort of + + align:start position:0% +comfortable with doing that sort of + + + align:start position:0% +comfortable with doing that sort of +thing + + align:start position:0% +thing + + + align:start position:0% +thing +right and you could see that we have a + + align:start position:0% +right and you could see that we have a + + + align:start position:0% +right and you could see that we have a +times the pizza the + + align:start position:0% +times the pizza the + + + align:start position:0% +times the pizza the +did I put the alien on the wrong order + + align:start position:0% +did I put the alien on the wrong order + + + align:start position:0% +did I put the alien on the wrong order +yep the aliens over here + + align:start position:0% +yep the aliens over here + + + align:start position:0% +yep the aliens over here +but you you get the idea + + align:start position:0% +but you you get the idea + + + align:start position:0% +but you you get the idea +right so you have a times Pizza alien + + align:start position:0% +right so you have a times Pizza alien + + + align:start position:0% +right so you have a times Pizza alien +panther cat B times Pizza alien Panda + + align:start position:0% +panther cat B times Pizza alien Panda + + + align:start position:0% +panther cat B times Pizza alien Panda +cat c times Pizza alien Panda cat D + + align:start position:0% +cat c times Pizza alien Panda cat D + + + align:start position:0% +cat c times Pizza alien Panda cat D +times those e times those F times those + + align:start position:0% +times those e times those F times those + + + align:start position:0% +times those e times those F times those +right I think you get the pattern you + + align:start position:0% +right I think you get the pattern you + + + align:start position:0% +right I think you get the pattern you +could do it in the other order oh let's + + align:start position:0% +could do it in the other order oh let's + + + align:start position:0% +could do it in the other order oh let's +see what else did we do + + align:start position:0% +see what else did we do + + + align:start position:0% +see what else did we do +uh oh here it is with the identity + + align:start position:0% +uh oh here it is with the identity + + + align:start position:0% +uh oh here it is with the identity +right so so it's this one is + + align:start position:0% +right so so it's this one is + + + align:start position:0% +right so so it's this one is +Pizza times one pizza times zero + + align:start position:0% +Pizza times one pizza times zero + + + align:start position:0% +Pizza times one pizza times zero +Pizza Time Zero Pizza times one alien + + align:start position:0% +Pizza Time Zero Pizza times one alien + + + align:start position:0% +Pizza Time Zero Pizza times one alien +times one alien times zero alien times + + align:start position:0% +times one alien times zero alien times + + + align:start position:0% +times one alien times zero alien times +zero alien yeah I think you all get it + + align:start position:0% +zero alien yeah I think you all get it + + + align:start position:0% +zero alien yeah I think you all get it +right + + align:start position:0% +right + + + align:start position:0% +right +but still fun to watch + + align:start position:0% +but still fun to watch + + + align:start position:0% +but still fun to watch +okay here it is in the other order + + align:start position:0% +okay here it is in the other order + + + align:start position:0% +okay here it is in the other order +so uh so this is one times Pizza alien + + align:start position:0% +so uh so this is one times Pizza alien + + + align:start position:0% +so uh so this is one times Pizza alien +Panda cat zero times Pizza alien right + + align:start position:0% +Panda cat zero times Pizza alien right + + + align:start position:0% +Panda cat zero times Pizza alien right +zero times the two and then again one + + align:start position:0% +zero times the two and then again one + + + align:start position:0% +zero times the two and then again one +times all of these funny symbols okay + + align:start position:0% +times all of these funny symbols okay + + + align:start position:0% +times all of these funny symbols okay +you get it + + align:start position:0% + + + + align:start position:0% + +yeah so the chronicle product with the + + align:start position:0% +yeah so the chronicle product with the + + + align:start position:0% +yeah so the chronicle product with the +identity is is a rather important + + align:start position:0% +identity is is a rather important + + + align:start position:0% +identity is is a rather important +special case right so here here it is + + align:start position:0% +special case right so here here it is + + + align:start position:0% +special case right so here here it is +with just the pqrs + + align:start position:0% +with just the pqrs + + + align:start position:0% +with just the pqrs +so here's the chronicle product of the + + align:start position:0% +so here's the chronicle product of the + + + align:start position:0% +so here's the chronicle product of the +transpose with the identity just putting + + align:start position:0% +transpose with the identity just putting + + + align:start position:0% +transpose with the identity just putting +everything in the other order and + + align:start position:0% +everything in the other order and + + + align:start position:0% +everything in the other order and +um + + align:start position:0% +um + + + align:start position:0% +um +and and what I want to demonstrate + + align:start position:0% +and and what I want to demonstrate + + + align:start position:0% +and and what I want to demonstrate +is that if you + + align:start position:0% +is that if you + + + align:start position:0% +is that if you +if you form the sum of these two + + align:start position:0% +if you form the sum of these two + + + align:start position:0% +if you form the sum of these two +Chronicle products as matrices + + align:start position:0% +Chronicle products as matrices + + + align:start position:0% +Chronicle products as matrices +and compare it with the Jacobian that + + align:start position:0% +and compare it with the Jacobian that + + + align:start position:0% +and compare it with the Jacobian that +you've already seen for the square + + align:start position:0% +you've already seen for the square + + + align:start position:0% +you've already seen for the square +function you'll notice that you get + + align:start position:0% +function you'll notice that you get + + + align:start position:0% +function you'll notice that you get +exactly the same expression + + align:start position:0% +exactly the same expression + + + align:start position:0% +exactly the same expression +okay so one way to write the Jacobian + + align:start position:0% +okay so one way to write the Jacobian + + + align:start position:0% +okay so one way to write the Jacobian +without writing the Jacobian is to just + + align:start position:0% +without writing the Jacobian is to just + + + align:start position:0% +without writing the Jacobian is to just +write these Chronicle products + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so you don't just because you write down + + align:start position:0% +so you don't just because you write down + + + align:start position:0% +so you don't just because you write down +the chronicle product it doesn't mean + + align:start position:0% +the chronicle product it doesn't mean + + + align:start position:0% +the chronicle product it doesn't mean +you actually have to multiply it all out + + align:start position:0% +you actually have to multiply it all out + + + align:start position:0% +you actually have to multiply it all out +though right you could write it as an + + align:start position:0% +though right you could write it as an + + + align:start position:0% +though right you could write it as an +expression okay and the what underlies + + align:start position:0% +expression okay and the what underlies + + + align:start position:0% +expression okay and the what underlies +everything and an identity that years + + align:start position:0% +everything and an identity that years + + + align:start position:0% +everything and an identity that years +ago I I remember I wrote this in big + + align:start position:0% +ago I I remember I wrote this in big + + + align:start position:0% +ago I I remember I wrote this in big +thick letters on an index card and I + + align:start position:0% +thick letters on an index card and I + + + align:start position:0% +thick letters on an index card and I +placed it on my bookshelf above my desk + + align:start position:0% +placed it on my bookshelf above my desk + + + align:start position:0% +placed it on my bookshelf above my desk +to make sure that I would never forget + + align:start position:0% +to make sure that I would never forget + + + align:start position:0% +to make sure that I would never forget +it so this is absolutely worth + + align:start position:0% +it so this is absolutely worth + + + align:start position:0% +it so this is absolutely worth +memorizing that if you have the right + + align:start position:0% +memorizing that if you have the right + + + align:start position:0% +memorizing that if you have the right +compatibility so that you know you can + + align:start position:0% +compatibility so that you know you can + + + align:start position:0% +compatibility so that you know you can +multiply B times c times a transpose + + align:start position:0% +multiply B times c times a transpose + + + align:start position:0% +multiply B times c times a transpose +right so the the number of columns of B + + align:start position:0% +right so the the number of columns of B + + + align:start position:0% +right so the the number of columns of B +has to be the number of rows of C Etc + + align:start position:0% +has to be the number of rows of C Etc + + + align:start position:0% +has to be the number of rows of C Etc +that the chronicle product of A and B + + align:start position:0% +that the chronicle product of A and B + + + align:start position:0% +that the chronicle product of A and B +when multiplied by the VEC of C + + align:start position:0% +when multiplied by the VEC of C + + + align:start position:0% +when multiplied by the VEC of C +always is identically equal to the VEC + + align:start position:0% +always is identically equal to the VEC + + + align:start position:0% +always is identically equal to the VEC +of BC a transpose okay so I would + + align:start position:0% +of BC a transpose okay so I would + + + align:start position:0% +of BC a transpose okay so I would +recommend memorizing that because it's + + align:start position:0% +recommend memorizing that because it's + + + align:start position:0% +recommend memorizing that because it's +just so handy to always know that + + align:start position:0% +just so handy to always know that + + + align:start position:0% +just so handy to always know that +okay and the the kind of mnemonic that I + + align:start position:0% +okay and the the kind of mnemonic that I + + + align:start position:0% +okay and the the kind of mnemonic that I +still have in my mind + + align:start position:0% +still have in my mind + + + align:start position:0% +still have in my mind +I mean you could just say to yourself + + align:start position:0% +I mean you could just say to yourself + + + align:start position:0% +I mean you could just say to yourself +BCA transpose but the way I kind of look + + align:start position:0% +BCA transpose but the way I kind of look + + + align:start position:0% +BCA transpose but the way I kind of look +at it and if this works for you that's + + align:start position:0% +at it and if this works for you that's + + + align:start position:0% +at it and if this works for you that's +fine and if it doesn't work you could + + align:start position:0% +fine and if it doesn't work you could + + + align:start position:0% +fine and if it doesn't work you could +have your own way but the way I look at + + align:start position:0% +have your own way but the way I look at + + + align:start position:0% +have your own way but the way I look at +this is I see I see the B is is is + + align:start position:0% +this is I see I see the B is is is + + + align:start position:0% +this is I see I see the B is is is +closest to the C on the left so I say BC + + align:start position:0% +closest to the C on the left so I say BC + + + align:start position:0% +closest to the C on the left so I say BC +and then I say ah the H then should go + + align:start position:0% +and then I say ah the H then should go + + + align:start position:0% +and then I say ah the H then should go +this is again a little memory thing it + + align:start position:0% +this is again a little memory thing it + + + align:start position:0% +this is again a little memory thing it +doesn't mean anything but the a should + + align:start position:0% +doesn't mean anything but the a should + + + align:start position:0% +doesn't mean anything but the a should +go around the other way and since it + + align:start position:0% +go around the other way and since it + + + align:start position:0% +go around the other way and since it +since it went around it deserves to be + + align:start position:0% +since it went around it deserves to be + + + align:start position:0% +since it went around it deserves to be +transposed + + align:start position:0% +transposed + + + align:start position:0% +transposed +so if that works for you that's fine the + + align:start position:0% +so if that works for you that's fine the + + + align:start position:0% +so if that works for you that's fine the +B is just to the left of the C the a has + + align:start position:0% +B is just to the left of the C the a has + + + align:start position:0% +B is just to the left of the C the a has +to come around so it gets transposed + + align:start position:0% +to come around so it gets transposed + + + align:start position:0% +to come around so it gets transposed +okay that somehow and that always works + + align:start position:0% +okay that somehow and that always works + + + align:start position:0% +okay that somehow and that always works +okay and so you can + + align:start position:0% +okay and so you can + + + align:start position:0% +okay and so you can +you know you can + + align:start position:0% +you know you can + + + align:start position:0% +you know you can +in fact here is some random here you can + + align:start position:0% +in fact here is some random here you can + + + align:start position:0% +in fact here is some random here you can +see with some random numbers right + + align:start position:0% +see with some random numbers right + + + align:start position:0% +see with some random numbers right +um + + align:start position:0% +um + + + align:start position:0% +um +where in fact I could I could type this + + align:start position:0% +where in fact I could I could type this + + + align:start position:0% +where in fact I could I could type this +till the cows come home it'll always + + align:start position:0% +till the cows come home it'll always + + + align:start position:0% +till the cows come home it'll always +come out to be a true identity so here + + align:start position:0% +come out to be a true identity so here + + + align:start position:0% +come out to be a true identity so here +we can I could hit it again but it'll + + align:start position:0% +we can I could hit it again but it'll + + + align:start position:0% +we can I could hit it again but it'll +always be true + + align:start position:0% +always be true + + + align:start position:0% +always be true +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +um you see it's b c a transpose okay + + align:start position:0% +um you see it's b c a transpose okay + + + align:start position:0% +um you see it's b c a transpose okay +everybody convinced + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +um + + align:start position:0% +um + + + align:start position:0% +um +so the chronicle product of two five by + + align:start position:0% +so the chronicle product of two five by + + + align:start position:0% +so the chronicle product of two five by +five matrices would be 25 by 25 just to + + align:start position:0% +five matrices would be 25 by 25 just to + + + align:start position:0% +five matrices would be 25 by 25 just to +show you and here are some useful + + align:start position:0% +show you and here are some useful + + + align:start position:0% +show you and here are some useful +identities uh worth knowing about so if + + align:start position:0% +identities uh worth knowing about so if + + + align:start position:0% +identities uh worth knowing about so if +you take the transpose of a Chronicle + + align:start position:0% +you take the transpose of a Chronicle + + + align:start position:0% +you take the transpose of a Chronicle +product + + align:start position:0% +product + + + align:start position:0% +product +it's the chronicle product of the + + align:start position:0% +it's the chronicle product of the + + + align:start position:0% +it's the chronicle product of the +transposes and it's not in the other + + align:start position:0% +transposes and it's not in the other + + + align:start position:0% +transposes and it's not in the other +order right like if this was if you were + + align:start position:0% +order right like if this was if you were + + + align:start position:0% +order right like if this was if you were +thinking of ordinary Matrix multiply + + align:start position:0% +thinking of ordinary Matrix multiply + + + align:start position:0% +thinking of ordinary Matrix multiply +you'd have a b transpose you know that + + align:start position:0% +you'd have a b transpose you know that + + + align:start position:0% +you'd have a b transpose you know that +would be B transpose a transpose but + + align:start position:0% +would be B transpose a transpose but + + + align:start position:0% +would be B transpose a transpose but +um when you do the chronicle product the + + align:start position:0% +um when you do the chronicle product the + + + align:start position:0% +um when you do the chronicle product the +order Remains the Same okay so don't get + + align:start position:0% +order Remains the Same okay so don't get + + + align:start position:0% +order Remains the Same okay so don't get +confused with Matrix multiplation + + align:start position:0% +confused with Matrix multiplation + + + align:start position:0% +confused with Matrix multiplation +again with inverse inverse if this + + align:start position:0% +again with inverse inverse if this + + + align:start position:0% +again with inverse inverse if this +wasn't a Chronicle product if it was a + + align:start position:0% +wasn't a Chronicle product if it was a + + + align:start position:0% +wasn't a Chronicle product if it was a +matrix multiply product again you would + + align:start position:0% +matrix multiply product again you would + + + align:start position:0% +matrix multiply product again you would +you would put this in the other order + + align:start position:0% +you would put this in the other order + + + align:start position:0% +you would put this in the other order +but with Chronicle product it stays in + + align:start position:0% +but with Chronicle product it stays in + + + align:start position:0% +but with Chronicle product it stays in +that order + + align:start position:0% +that order + + + align:start position:0% +that order +another useful thing to know is if a and + + align:start position:0% +another useful thing to know is if a and + + + align:start position:0% +another useful thing to know is if a and +b are square matrices if a is n by n and + + align:start position:0% +b are square matrices if a is n by n and + + + align:start position:0% +b are square matrices if a is n by n and +B is M by m + + align:start position:0% +B is M by m + + + align:start position:0% +B is M by m +then the determinant is the determinant + + align:start position:0% +then the determinant is the determinant + + + align:start position:0% +then the determinant is the determinant +of a to the m so so a is the n by N1 it + + align:start position:0% +of a to the m so so a is the n by N1 it + + + align:start position:0% +of a to the m so so a is the n by N1 it +picks up the M from the B and then B is + + align:start position:0% +picks up the M from the B and then B is + + + align:start position:0% +picks up the M from the B and then B is +the m by M1 it takes picks up the N from + + align:start position:0% +the m by M1 it takes picks up the N from + + + align:start position:0% +the m by M1 it takes picks up the N from +the a right so there's a formula + + align:start position:0% +the a right so there's a formula + + + align:start position:0% +the a right so there's a formula +um the trace of a Chronicle product is + + align:start position:0% +um the trace of a Chronicle product is + + + align:start position:0% +um the trace of a Chronicle product is +the product of the traces + + align:start position:0% +the product of the traces + + + align:start position:0% +the product of the traces +um a chronic or B is orthogonal if a and + + align:start position:0% +um a chronic or B is orthogonal if a and + + + align:start position:0% +um a chronic or B is orthogonal if a and +b are both orthogonal + + align:start position:0% +b are both orthogonal + + + align:start position:0% +b are both orthogonal +The Matrix multiply of A chronography + + align:start position:0% +The Matrix multiply of A chronography + + + align:start position:0% +The Matrix multiply of A chronography +and C chronic or D is the Matrix + + align:start position:0% +and C chronic or D is the Matrix + + + align:start position:0% +and C chronic or D is the Matrix +multiply of A and C with that of B and D + + align:start position:0% +multiply of A and C with that of B and D + + + align:start position:0% +multiply of A and C with that of B and D +and + + align:start position:0% +and + + + align:start position:0% +and +yeah so so a chronic or B and B + + align:start position:0% +yeah so so a chronic or B and B + + + align:start position:0% +yeah so so a chronic or B and B +Chronicle a have the same eigenvalues + + align:start position:0% +Chronicle a have the same eigenvalues + + + align:start position:0% +Chronicle a have the same eigenvalues +which are actually the products of the + + align:start position:0% +which are actually the products of the + + + align:start position:0% +which are actually the products of the +eigenvalues of A and B separately and + + align:start position:0% +eigenvalues of A and B separately and + + + align:start position:0% +eigenvalues of A and B separately and +the eigenvectors are just transposed of + + align:start position:0% +the eigenvectors are just transposed of + + + align:start position:0% +the eigenvectors are just transposed of +each other + + align:start position:0% +each other + + + align:start position:0% +each other +okay and so uh + + align:start position:0% +okay and so uh + + + align:start position:0% +okay and so uh +so so maybe this is worth writing out on + + align:start position:0% +so so maybe this is worth writing out on + + + align:start position:0% +so so maybe this is worth writing out on +the board just to see it but this is + + align:start position:0% +the board just to see it but this is + + + align:start position:0% +the board just to see it but this is +kind of how I like to do this so + + align:start position:0% +kind of how I like to do this so + + + align:start position:0% +kind of how I like to do this so +if somebody tells me to talk about the + + align:start position:0% +if somebody tells me to talk about the + + + align:start position:0% +if somebody tells me to talk about the +derivative this this is my favorite way + + align:start position:0% +derivative this this is my favorite way + + + align:start position:0% +derivative this this is my favorite way +of seeing the derivative of x squared + + align:start position:0% +of seeing the derivative of x squared + + + align:start position:0% +of seeing the derivative of x squared +okay so I'm going to go over here and + + align:start position:0% +okay so I'm going to go over here and + + + align:start position:0% +okay so I'm going to go over here and +I'm going to say + + align:start position:0% +I'm going to say + + + align:start position:0% +I'm going to say +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +the derivative of x squared + + align:start position:0% +the derivative of x squared + + + align:start position:0% +the derivative of x squared +which we've all known to we've seen this + + align:start position:0% +which we've all known to we've seen this + + + align:start position:0% +which we've all known to we've seen this +now a few times I'm going to use this + + align:start position:0% +now a few times I'm going to use this + + + align:start position:0% +now a few times I'm going to use this +white truck the derivative of x squared + + align:start position:0% +white truck the derivative of x squared + + + align:start position:0% +white truck the derivative of x squared +of course is going to be the Matrix x + + align:start position:0% +of course is going to be the Matrix x + + + align:start position:0% +of course is going to be the Matrix x +times DX plus DX + + align:start position:0% +times DX plus DX + + + align:start position:0% +times DX plus DX +X from the product rule okay + + align:start position:0% +X from the product rule okay + + + align:start position:0% +X from the product rule okay +but I'm going to look at this and I'm + + align:start position:0% +but I'm going to look at this and I'm + + + align:start position:0% +but I'm going to look at this and I'm +going to say in my mind this is x t x i + + align:start position:0% +going to say in my mind this is x t x i + + + align:start position:0% +going to say in my mind this is x t x i +right and this is i d x x + + align:start position:0% +right and this is i d x x + + + align:start position:0% +right and this is i d x x +I normally wouldn't write that out but + + align:start position:0% +I normally wouldn't write that out but + + + align:start position:0% +I normally wouldn't write that out but +just for purposes of showing you folks + + align:start position:0% +just for purposes of showing you folks + + + align:start position:0% +just for purposes of showing you folks +I'll put the identity Matrix in okay and + + align:start position:0% +I'll put the identity Matrix in okay and + + + align:start position:0% +I'll put the identity Matrix in okay and +then I would say that + + align:start position:0% +then I would say that + + + align:start position:0% +then I would say that +that uh what do which chronic or product + + align:start position:0% +that uh what do which chronic or product + + + align:start position:0% +that uh what do which chronic or product +do I need well let's see + + align:start position:0% +do I need well let's see + + + align:start position:0% +do I need well let's see +the thing that's on the left is going to + + align:start position:0% +the thing that's on the left is going to + + + align:start position:0% +the thing that's on the left is going to +be closest to the DX so I'll put the X + + align:start position:0% +be closest to the DX so I'll put the X + + + align:start position:0% +be closest to the DX so I'll put the X +here right and then this I would be + + align:start position:0% +here right and then this I would be + + + align:start position:0% +here right and then this I would be +transposed but since it's the identity I + + align:start position:0% +transposed but since it's the identity I + + + align:start position:0% +transposed but since it's the identity I +don't have to write that out okay and + + align:start position:0% +don't have to write that out okay and + + + align:start position:0% +don't have to write that out okay and +then here + + align:start position:0% +then here + + + align:start position:0% +then here +you see the same game the thing that's + + align:start position:0% +you see the same game the thing that's + + + align:start position:0% +you see the same game the thing that's +to the left of the DX is the I this + + align:start position:0% +to the left of the DX is the I this + + + align:start position:0% +to the left of the DX is the I this +thing then has to be X transpose + + align:start position:0% +thing then has to be X transpose + + + align:start position:0% +thing then has to be X transpose +okay and so + + align:start position:0% +okay and so + + + align:start position:0% +okay and so +one one thing you could write is the VEC + + align:start position:0% +one one thing you could write is the VEC + + + align:start position:0% +one one thing you could write is the VEC +but I don't really like this but this + + align:start position:0% +but I don't really like this but this + + + align:start position:0% +but I don't really like this but this +would be reasonable to write the VEC of + + align:start position:0% +would be reasonable to write the VEC of + + + align:start position:0% +would be reasonable to write the VEC of +DX squared + + align:start position:0% +DX squared + + + align:start position:0% +DX squared +is this times the vector of x + + align:start position:0% +is this times the vector of x + + + align:start position:0% +is this times the vector of x +okay and this is expressing it's just + + align:start position:0% +okay and this is expressing it's just + + + align:start position:0% +okay and this is expressing it's just +another notation for what's over there + + align:start position:0% +another notation for what's over there + + + align:start position:0% +another notation for what's over there +okay but what I really like to write is + + align:start position:0% +okay but what I really like to write is + + + align:start position:0% +okay but what I really like to write is +I like to think of this as a linear + + align:start position:0% +I like to think of this as a linear + + + align:start position:0% +I like to think of this as a linear +operator and maybe I'll use the square + + align:start position:0% +operator and maybe I'll use the square + + + align:start position:0% +operator and maybe I'll use the square +brackets that Stephen likes to use and I + + align:start position:0% +brackets that Stephen likes to use and I + + + align:start position:0% +brackets that Stephen likes to use and I +think I would the one I would enjoy the + + align:start position:0% +think I would the one I would enjoy the + + + align:start position:0% +think I would the one I would enjoy the +most to write if I have to put + + align:start position:0% +most to write if I have to put + + + align:start position:0% +most to write if I have to put +everything on the you see there's + + align:start position:0% +everything on the you see there's + + + align:start position:0% +everything on the you see there's +something nice about putting the DX on + + align:start position:0% +something nice about putting the DX on + + + align:start position:0% +something nice about putting the DX on +the on the right so I think this is the + + align:start position:0% +the on the right so I think this is the + + + align:start position:0% +the on the right so I think this is the +notation that I would like the best this + + align:start position:0% +notation that I would like the best this + + + align:start position:0% +notation that I would like the best this +is equal to this as an operator acting + + align:start position:0% +is equal to this as an operator acting + + + align:start position:0% +is equal to this as an operator acting +on the X and + + align:start position:0% +on the X and + + + align:start position:0% +on the X and +okay and by that what I mean by that is + + align:start position:0% +okay and by that what I mean by that is + + + align:start position:0% +okay and by that what I mean by that is +if I ever have a chronic or B + + align:start position:0% +if I ever have a chronic or B + + + align:start position:0% +if I ever have a chronic or B +acting on anything + + align:start position:0% +acting on anything + + + align:start position:0% +acting on anything +I'll just call it m + + align:start position:0% +I'll just call it m + + + align:start position:0% +I'll just call it m +I'm going to have that mean + + align:start position:0% +I'm going to have that mean + + + align:start position:0% +I'm going to have that mean +a m sorry BM a transpose + + align:start position:0% +a m sorry BM a transpose + + + align:start position:0% +a m sorry BM a transpose +right so that would be my definition of + + align:start position:0% +right so that would be my definition of + + + align:start position:0% +right so that would be my definition of +a chronic or bracket with square with a + + align:start position:0% +a chronic or bracket with square with a + + + align:start position:0% +a chronic or bracket with square with a +square input + + align:start position:0% +square input + + + align:start position:0% +square input +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so + + align:start position:0% +so + + + align:start position:0% +so +if you want to have the DX all on one + + align:start position:0% +if you want to have the DX all on one + + + align:start position:0% +if you want to have the DX all on one +side this is how I would do it yes + + align:start position:0% + + + + align:start position:0% + +effective DX thank you you are quite + + align:start position:0% +effective DX thank you you are quite + + + align:start position:0% +effective DX thank you you are quite +right + + align:start position:0% +right + + + align:start position:0% +right +good thanks for the catch perfect + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so + + align:start position:0% +so + + + align:start position:0% +so +so that's basically what I'm writing + + align:start position:0% +so that's basically what I'm writing + + + align:start position:0% +so that's basically what I'm writing +here in this part of the notes over here + + align:start position:0% +here in this part of the notes over here + + + align:start position:0% +here in this part of the notes over here +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and again this is I I often don't even + + align:start position:0% +and again this is I I often don't even + + + align:start position:0% +and again this is I I often don't even +put the square bracket so what I maybe + + align:start position:0% +put the square bracket so what I maybe + + + align:start position:0% +put the square bracket so what I maybe +it's not a bad idea to avoid confusion + + align:start position:0% +it's not a bad idea to avoid confusion + + + align:start position:0% +it's not a bad idea to avoid confusion +so uh + + align:start position:0% +so uh + + + align:start position:0% +so uh +kind of following Stephen's notation it + + align:start position:0% +kind of following Stephen's notation it + + + align:start position:0% +kind of following Stephen's notation it +would be sort of like this would be the + + align:start position:0% +would be sort of like this would be the + + + align:start position:0% +would be sort of like this would be the +way to do it as this chronic or operator + + align:start position:0% +way to do it as this chronic or operator + + + align:start position:0% +way to do it as this chronic or operator +acting on DX + + align:start position:0% +acting on DX + + + align:start position:0% +acting on DX +I find that there's never any real + + align:start position:0% +I find that there's never any real + + + align:start position:0% +I find that there's never any real +confusion and so I don't I don't write + + align:start position:0% +confusion and so I don't I don't write + + + align:start position:0% +confusion and so I don't I don't write +the VEC I don't put a square bracket I + + align:start position:0% +the VEC I don't put a square bracket I + + + align:start position:0% +the VEC I don't put a square bracket I +just do this I think I'm the only one + + align:start position:0% +just do this I think I'm the only one + + + align:start position:0% +just do this I think I'm the only one +who does this so there's no reason why + + align:start position:0% +who does this so there's no reason why + + + align:start position:0% +who does this so there's no reason why +you should follow me but I find it quite + + align:start position:0% +you should follow me but I find it quite + + + align:start position:0% +you should follow me but I find it quite +nice to just write it this way and drop + + align:start position:0% +nice to just write it this way and drop + + + align:start position:0% +nice to just write it this way and drop +the back I I think there's never any + + align:start position:0% +the back I I think there's never any + + + align:start position:0% +the back I I think there's never any +confusion this is an operator acting on + + align:start position:0% +confusion this is an operator acting on + + + align:start position:0% +confusion this is an operator acting on +the DX in just the way we say + + align:start position:0% +the DX in just the way we say + + + align:start position:0% +the DX in just the way we say +okay so you get to make your own choice + + align:start position:0% +okay so you get to make your own choice + + + align:start position:0% +okay so you get to make your own choice +that's how I like to do it + + align:start position:0% +that's how I like to do it + + + align:start position:0% +that's how I like to do it +all right uh + + align:start position:0% +all right uh + + + align:start position:0% +all right uh +okay so just to show off + + align:start position:0% +okay so just to show off + + + align:start position:0% +okay so just to show off +um a little bit in in Julia + + align:start position:0% +um a little bit in in Julia + + + align:start position:0% +um a little bit in in Julia +um so we can get these jacobians and + + align:start position:0% +um so we can get these jacobians and + + + align:start position:0% +um so we can get these jacobians and +Trulia using the automatic + + align:start position:0% +Trulia using the automatic + + + align:start position:0% +Trulia using the automatic +differentiation okay and we're going to + + align:start position:0% +differentiation okay and we're going to + + + align:start position:0% +differentiation okay and we're going to +talk about automatic differentiation I + + align:start position:0% +talk about automatic differentiation I + + + align:start position:0% +talk about automatic differentiation I +would imagine I don't know if it's later + + align:start position:0% +would imagine I don't know if it's later + + + align:start position:0% +would imagine I don't know if it's later +this week or or when are we talking + + align:start position:0% +this week or or when are we talking + + + align:start position:0% +this week or or when are we talking +about A.D Steven do we do we know later + + align:start position:0% +about A.D Steven do we do we know later + + + align:start position:0% +about A.D Steven do we do we know later +this week or maybe next week yeah I + + align:start position:0% +this week or maybe next week yeah I + + + align:start position:0% +this week or maybe next week yeah I +think probably like by Friday or + + align:start position:0% +think probably like by Friday or + + + align:start position:0% +think probably like by Friday or +something like that all right maybe by + + align:start position:0% +something like that all right maybe by + + + align:start position:0% +something like that all right maybe by +Friday we'll talk about automatic + + align:start position:0% +Friday we'll talk about automatic + + + align:start position:0% +Friday we'll talk about automatic +differentiation uh so the the key + + align:start position:0% +differentiation uh so the the key + + + align:start position:0% +differentiation uh so the the key +introduction for those of you who've + + align:start position:0% +introduction for those of you who've + + + align:start position:0% +introduction for those of you who've +never seen ad is that it's not symbolic + + align:start position:0% +never seen ad is that it's not symbolic + + + align:start position:0% +never seen ad is that it's not symbolic +like Mathematica and it's not numerical + + align:start position:0% +like Mathematica and it's not numerical + + + align:start position:0% +like Mathematica and it's not numerical +finite differences right it's it's none + + align:start position:0% +finite differences right it's it's none + + + align:start position:0% +finite differences right it's it's none +of those things it's something + + align:start position:0% +of those things it's something + + + align:start position:0% +of those things it's something +I mean of course it's mathematically + + align:start position:0% +I mean of course it's mathematically + + + align:start position:0% +I mean of course it's mathematically +equivalent and but it's it's when I + + align:start position:0% +equivalent and but it's it's when I + + + align:start position:0% +equivalent and but it's it's when I +first saw it I was kind of surprised as + + align:start position:0% +first saw it I was kind of surprised as + + + align:start position:0% +first saw it I was kind of surprised as +to exactly how it works + + align:start position:0% +to exactly how it works + + + align:start position:0% +to exactly how it works +so uh you might be surprised too but + + align:start position:0% +so uh you might be surprised too but + + + align:start position:0% +so uh you might be surprised too but +right now we're just going to be users + + align:start position:0% +right now we're just going to be users + + + align:start position:0% +right now we're just going to be users +I'm just going to grab here's that J + + align:start position:0% +I'm just going to grab here's that J + + + align:start position:0% +I'm just going to grab here's that J +Matrix and I'm just going to point out + + align:start position:0% +Matrix and I'm just going to point out + + + align:start position:0% +Matrix and I'm just going to point out +that if it'll compute the Jacobian of + + align:start position:0% +that if it'll compute the Jacobian of + + + align:start position:0% +that if it'll compute the Jacobian of +the square function at the point M right + + align:start position:0% +the square function at the point M right + + + align:start position:0% +the square function at the point M right +and we could check that it gives the + + align:start position:0% +and we could check that it gives the + + + align:start position:0% +and we could check that it gives the +right answer + + align:start position:0% +right answer + + + align:start position:0% +right answer +okay and in fact it'll work with symbols + + align:start position:0% +okay and in fact it'll work with symbols + + + align:start position:0% +okay and in fact it'll work with symbols +as well as at right so in some sense + + align:start position:0% +as well as at right so in some sense + + + align:start position:0% +as well as at right so in some sense +here we're getting the Jacobian at every + + align:start position:0% +here we're getting the Jacobian at every + + + align:start position:0% +here we're getting the Jacobian at every +point + + align:start position:0% +point + + + align:start position:0% +point +right because the you know the the + + align:start position:0% +right because the you know the the + + + align:start position:0% +right because the you know the the +elements are variables + + align:start position:0% +elements are variables + + + align:start position:0% +elements are variables +all right let's do everything we just + + align:start position:0% +all right let's do everything we just + + + align:start position:0% +all right let's do everything we just +did but let's let's kind of move up to + + align:start position:0% +did but let's let's kind of move up to + + + align:start position:0% +did but let's let's kind of move up to +the Matrix Cube function + + align:start position:0% +the Matrix Cube function + + + align:start position:0% +the Matrix Cube function +so here's the Matrix Cube function for + + align:start position:0% +so here's the Matrix Cube function for + + + align:start position:0% +so here's the Matrix Cube function for +two by two matrices written out in all + + align:start position:0% +two by two matrices written out in all + + + align:start position:0% +two by two matrices written out in all +of its Glory + + align:start position:0% +of its Glory + + + align:start position:0% +of its Glory +this is the sort of thing that if I did + + align:start position:0% +this is the sort of thing that if I did + + + align:start position:0% +this is the sort of thing that if I did +it on the Blackboard + + align:start position:0% +it on the Blackboard + + + align:start position:0% +it on the Blackboard +just writing it out would take a little + + align:start position:0% +just writing it out would take a little + + + align:start position:0% +just writing it out would take a little +too long but the computer doesn't mind + + align:start position:0% +too long but the computer doesn't mind + + + align:start position:0% +too long but the computer doesn't mind +right so there's the there's the Matrix + + align:start position:0% +right so there's the there's the Matrix + + + align:start position:0% +right so there's the there's the Matrix +Cube function right I mean the computer + + align:start position:0% +Cube function right I mean the computer + + + align:start position:0% +Cube function right I mean the computer +wouldn't care if I did x to the fourth + + align:start position:0% +wouldn't care if I did x to the fourth + + + align:start position:0% +wouldn't care if I did x to the fourth +I assume let's see what point does it + + align:start position:0% +I assume let's see what point does it + + + align:start position:0% +I assume let's see what point does it +get hairy maybe at the fifth it's kind + + align:start position:0% +get hairy maybe at the fifth it's kind + + + align:start position:0% +get hairy maybe at the fifth it's kind +of well you'd have to scroll but there + + align:start position:0% +of well you'd have to scroll but there + + + align:start position:0% +of well you'd have to scroll but there +it is + + align:start position:0% +it is + + + align:start position:0% +it is +okay so let's do the cube + + align:start position:0% +okay so let's do the cube + + + align:start position:0% +okay so let's do the cube +all right so there's the Matrix Cube + + align:start position:0% +all right so there's the Matrix Cube + + + align:start position:0% +all right so there's the Matrix Cube +function + + align:start position:0% +function + + + align:start position:0% +function +okay and uh + + align:start position:0% +okay and uh + + + align:start position:0% +okay and uh +we can we we can get the Jacobian again + + align:start position:0% +we can we we can get the Jacobian again + + + align:start position:0% +we can we we can get the Jacobian again +it's just a matter of just to remind you + + align:start position:0% +it's just a matter of just to remind you + + + align:start position:0% +it's just a matter of just to remind you +that there's nothing I'm just laying the + + align:start position:0% +that there's nothing I'm just laying the + + + align:start position:0% +that there's nothing I'm just laying the +computer do the work but you all could + + align:start position:0% +computer do the work but you all could + + + align:start position:0% +computer do the work but you all could +do it if I took the derivative of this + + align:start position:0% +do it if I took the derivative of this + + + align:start position:0% +do it if I took the derivative of this +respect to P you get this expression + + align:start position:0% +respect to P you get this expression + + + align:start position:0% +respect to P you get this expression +there is with respect to Q you'd get RS + + align:start position:0% +there is with respect to Q you'd get RS + + + align:start position:0% +there is with respect to Q you'd get RS +plus two two PR right you can all do + + align:start position:0% +plus two two PR right you can all do + + + align:start position:0% +plus two two PR right you can all do +this derivative with respect to S and + + align:start position:0% +this derivative with respect to S and + + + align:start position:0% +this derivative with respect to S and +the derivative with respect to T and + + align:start position:0% +the derivative with respect to T and + + + align:start position:0% +the derivative with respect to T and +then you move down and do the same for + + align:start position:0% +then you move down and do the same for + + + align:start position:0% +then you move down and do the same for +this one and then this one then this one + + align:start position:0% +this one and then this one then this one + + + align:start position:0% +this one and then this one then this one +right but let the computer do the work + + align:start position:0% +right but let the computer do the work + + + align:start position:0% +right but let the computer do the work +and so here's all the 16 derivatives you + + align:start position:0% +and so here's all the 16 derivatives you + + + align:start position:0% +and so here's all the 16 derivatives you +know right here in our faces + + align:start position:0% +know right here in our faces + + + align:start position:0% +know right here in our faces +um and uh + + align:start position:0% +um and uh + + + align:start position:0% +um and uh +uh here let's see um so these are just + + align:start position:0% +uh here let's see um so these are just + + + align:start position:0% +uh here let's see um so these are just +two different ways to basically I guess + + align:start position:0% +two different ways to basically I guess + + + align:start position:0% +two different ways to basically I guess +write the same thing + + align:start position:0% +write the same thing + + + align:start position:0% +write the same thing +um so but of course we would you we + + align:start position:0% +um so but of course we would you we + + + align:start position:0% +um so but of course we would you we +would like to use the product rule so it + + align:start position:0% +would like to use the product rule so it + + + align:start position:0% +would like to use the product rule so it +would be DX times x squared plus X dxx + + align:start position:0% +would be DX times x squared plus X dxx + + + align:start position:0% +would be DX times x squared plus X dxx +Plus dxx squared right so Stephen showed + + align:start position:0% +Plus dxx squared right so Stephen showed + + + align:start position:0% +Plus dxx squared right so Stephen showed +you that I think the other day right and + + align:start position:0% +you that I think the other day right and + + + align:start position:0% +you that I think the other day right and +this cannot be simplified really I mean + + align:start position:0% +this cannot be simplified really I mean + + + align:start position:0% +this cannot be simplified really I mean +you could change notation but you can't + + align:start position:0% +you could change notation but you can't + + + align:start position:0% +you could change notation but you can't +combine any of these terms right so of + + align:start position:0% +combine any of these terms right so of + + + align:start position:0% +combine any of these terms right so of +course if it's a scalar + + align:start position:0% +course if it's a scalar + + + align:start position:0% +course if it's a scalar +if everything was a scalar this would + + align:start position:0% +if everything was a scalar this would + + + align:start position:0% +if everything was a scalar this would +this would amount to 3x squared DX which + + align:start position:0% +this would amount to 3x squared DX which + + + align:start position:0% +this would amount to 3x squared DX which +which is the ordinary 1801 kind of + + align:start position:0% +which is the ordinary 1801 kind of + + + align:start position:0% +which is the ordinary 1801 kind of +answer but for matrices this is all you + + align:start position:0% +answer but for matrices this is all you + + + align:start position:0% +answer but for matrices this is all you +get and so if you want to write this as + + align:start position:0% +get and so if you want to write this as + + + align:start position:0% +get and so if you want to write this as +a function as a linear function where e + + align:start position:0% +a function as a linear function where e + + + align:start position:0% +a function as a linear function where e +is the DX and M is the X you see that + + align:start position:0% +is the DX and M is the X you see that + + + align:start position:0% +is the DX and M is the X you see that +right so here I'm just just I guess I'm + + align:start position:0% +right so here I'm just just I guess I'm + + + align:start position:0% +right so here I'm just just I guess I'm +just using another notation where + + align:start position:0% +just using another notation where + + + align:start position:0% +just using another notation where +of E and M oops + + align:start position:0% + + + + align:start position:0% + +you know for the X and X right so I'm + + align:start position:0% +you know for the X and X right so I'm + + + align:start position:0% +you know for the X and X right so I'm +just using these variables right this is + + align:start position:0% +just using these variables right this is + + + align:start position:0% +just using these variables right this is +the linear function right and again + + align:start position:0% +the linear function right and again + + + align:start position:0% +the linear function right and again +you know it takes sometimes it takes a + + align:start position:0% +you know it takes sometimes it takes a + + + align:start position:0% +you know it takes sometimes it takes a +little getting used to it's like you + + align:start position:0% +little getting used to it's like you + + + align:start position:0% +little getting used to it's like you +might look in this and say wait this is + + align:start position:0% +might look in this and say wait this is + + + align:start position:0% +might look in this and say wait this is +not a linear function I mean I've got an + + align:start position:0% +not a linear function I mean I've got an + + + align:start position:0% +not a linear function I mean I've got an +M squared right or M times ETA this is + + align:start position:0% +M squared right or M times ETA this is + + + align:start position:0% +M squared right or M times ETA this is +not linear but why do I get to tell you + + align:start position:0% +not linear but why do I get to tell you + + + align:start position:0% +not linear but why do I get to tell you +that this is a linear function you've + + align:start position:0% +that this is a linear function you've + + + align:start position:0% +that this is a linear function you've +got squaring of M that's not linear + + align:start position:0% +got squaring of M that's not linear + + + align:start position:0% +got squaring of M that's not linear +squaring is not linear what + + align:start position:0% +squaring is not linear what + + + align:start position:0% +squaring is not linear what +it's linear in E Bingo right so this + + align:start position:0% +it's linear in E Bingo right so this + + + align:start position:0% +it's linear in E Bingo right so this +function is linear in E and that's all + + align:start position:0% +function is linear in E and that's all + + + align:start position:0% +function is linear in E and that's all +that ever matters right and I'll even + + align:start position:0% +that ever matters right and I'll even + + + align:start position:0% +that ever matters right and I'll even +remind you in ordinary freshman calculus + + align:start position:0% +remind you in ordinary freshman calculus + + + align:start position:0% +remind you in ordinary freshman calculus +that the derivative of x cubed 3x + + align:start position:0% +that the derivative of x cubed 3x + + + align:start position:0% +that the derivative of x cubed 3x +squared is not linear in X right the + + align:start position:0% +squared is not linear in X right the + + + align:start position:0% +squared is not linear in X right the +derivative actually is very non-linear + + align:start position:0% +derivative actually is very non-linear + + + align:start position:0% +derivative actually is very non-linear +in X it's quadratic in X right but what + + align:start position:0% +in X it's quadratic in X right but what + + + align:start position:0% +in X it's quadratic in X right but what +is linear is that if that if you make a + + align:start position:0% +is linear is that if that if you make a + + + align:start position:0% +is linear is that if that if you make a +perturbation e to the X then um the the + + align:start position:0% +perturbation e to the X then um the the + + + align:start position:0% +perturbation e to the X then um the the +the output is pertured by three x + + align:start position:0% +the output is pertured by three x + + + align:start position:0% +the output is pertured by three x +squared times e right and that is linear + + align:start position:0% +squared times e right and that is linear + + + align:start position:0% +squared times e right and that is linear +right so so this is what's going on in + + align:start position:0% +right so so this is what's going on in + + + align:start position:0% +right so so this is what's going on in +Matrix land + + align:start position:0% +Matrix land + + + align:start position:0% +Matrix land +okay here's a numerical finite + + align:start position:0% +okay here's a numerical finite + + + align:start position:0% +okay here's a numerical finite +difference here is this function applied + + align:start position:0% +difference here is this function applied + + + align:start position:0% +difference here is this function applied +to e and as usual you see that to the to + + align:start position:0% +to e and as usual you see that to the to + + + align:start position:0% +to e and as usual you see that to the to +a reasonable number of digits you get + + align:start position:0% +a reasonable number of digits you get + + + align:start position:0% +a reasonable number of digits you get +the same answer all right so Julia's + + align:start position:0% +the same answer all right so Julia's + + + align:start position:0% +the same answer all right so Julia's +this is Julia's function this linear + + align:start position:0% +this is Julia's function this linear + + + align:start position:0% +this is Julia's function this linear +function right here applied to the + + align:start position:0% +function right here applied to the + + + align:start position:0% +function right here applied to the +perturbation e + + align:start position:0% +perturbation e + + + align:start position:0% +perturbation e +right so the e e here is a dummy + + align:start position:0% +right so the e e here is a dummy + + + align:start position:0% +right so the e e here is a dummy +variable it's just the dummy variable + + align:start position:0% +variable it's just the dummy variable + + + align:start position:0% +variable it's just the dummy variable +for the function and then here e is the + + align:start position:0% +for the function and then here e is the + + + align:start position:0% +for the function and then here e is the +numerical perturbation that I'm making + + align:start position:0% +numerical perturbation that I'm making + + + align:start position:0% +numerical perturbation that I'm making +okay so is play having two roles here + + align:start position:0% +okay so is play having two roles here + + + align:start position:0% +okay so is play having two roles here +okay and + + align:start position:0% +okay and + + + align:start position:0% +okay and +we could check against the symbolic + + align:start position:0% +we could check against the symbolic + + + align:start position:0% +we could check against the symbolic +answer and of course I don't know how + + align:start position:0% +answer and of course I don't know how + + + align:start position:0% +answer and of course I don't know how +easy it is to see it maybe I'll just + + align:start position:0% +easy it is to see it maybe I'll just + + + align:start position:0% +easy it is to see it maybe I'll just +flatten up here but you could see that + + align:start position:0% +flatten up here but you could see that + + + align:start position:0% +flatten up here but you could see that +these numbers that are about to go off + + align:start position:0% +these numbers that are about to go off + + + align:start position:0% +these numbers that are about to go off +screen here are exactly the same here so + + align:start position:0% +screen here are exactly the same here so + + + align:start position:0% +screen here are exactly the same here so +everything checks out it all works out + + align:start position:0% +everything checks out it all works out + + + align:start position:0% +everything checks out it all works out +you get the right answer so how do we do + + align:start position:0% +you get the right answer so how do we do + + + align:start position:0% +you get the right answer so how do we do +this with the chronicle notation + + align:start position:0% +this with the chronicle notation + + + align:start position:0% +this with the chronicle notation +well um I think you know here let's just + + align:start position:0% +well um I think you know here let's just + + + align:start position:0% +well um I think you know here let's just +do this one on the Blackboard as well + + align:start position:0% +do this one on the Blackboard as well + + + align:start position:0% +do this one on the Blackboard as well +just just to do it + + align:start position:0% +just just to do it + + + align:start position:0% +just just to do it +so I'm just going to do the very same + + align:start position:0% +so I'm just going to do the very same + + + align:start position:0% +so I'm just going to do the very same +thing here but I'll do it for X cubed + + align:start position:0% + + + + align:start position:0% + +just + + align:start position:0% +just + + + align:start position:0% +just +just to get the practice right so + + align:start position:0% +just to get the practice right so + + + align:start position:0% +just to get the practice right so +the xq version of what's here is going + + align:start position:0% +the xq version of what's here is going + + + align:start position:0% +the xq version of what's here is going +to be x squared DX plus X DX X plus d x + + align:start position:0% +to be x squared DX plus X DX X plus d x + + + align:start position:0% +to be x squared DX plus X DX X plus d x +x squared right + + align:start position:0% +x squared right + + + align:start position:0% +x squared right +okay and I'm going to look at this and + + align:start position:0% +okay and I'm going to look at this and + + + align:start position:0% +okay and I'm going to look at this and +say aha I Chronicle x squared right + + align:start position:0% +say aha I Chronicle x squared right + + + align:start position:0% +say aha I Chronicle x squared right +because x squared is multiplying DX on + + align:start position:0% +because x squared is multiplying DX on + + + align:start position:0% +because x squared is multiplying DX on +the left + + align:start position:0% +the left + + + align:start position:0% +the left +here I'm going to look at this and say + + align:start position:0% +here I'm going to look at this and say + + + align:start position:0% +here I'm going to look at this and say +there's an X and an X transpose right + + align:start position:0% +there's an X and an X transpose right + + + align:start position:0% +there's an X and an X transpose right +because X is on the left and and X is on + + align:start position:0% +because X is on the left and and X is on + + + align:start position:0% +because X is on the left and and X is on +the right but it comes around and it + + align:start position:0% +the right but it comes around and it + + + align:start position:0% +the right but it comes around and it +gets transposed right and this one I'm + + align:start position:0% +gets transposed right and this one I'm + + + align:start position:0% +gets transposed right and this one I'm +going to say is X transpose squared + + align:start position:0% +going to say is X transpose squared + + + align:start position:0% +going to say is X transpose squared +Chronicle I because it's on the right + + align:start position:0% +Chronicle I because it's on the right + + + align:start position:0% +Chronicle I because it's on the right +and so + + align:start position:0% +and so + + + align:start position:0% +and so +whatever is on the right here goes on + + align:start position:0% +whatever is on the right here goes on + + + align:start position:0% +whatever is on the right here goes on +the left here and gets transposed right + + align:start position:0% +the left here and gets transposed right + + + align:start position:0% +the left here and gets transposed right +and + + align:start position:0% +and + + + align:start position:0% +and +what I would write + + align:start position:0% +what I would write + + + align:start position:0% +what I would write +is + + align:start position:0% +is + + + align:start position:0% +is +this + + align:start position:0% + + + + align:start position:0% + +but if you want to put in the square + + align:start position:0% +but if you want to put in the square + + + align:start position:0% +but if you want to put in the square +brackets to emphasize this is an + + align:start position:0% +brackets to emphasize this is an + + + align:start position:0% +brackets to emphasize this is an +operator that's fine by me right or you + + align:start position:0% +operator that's fine by me right or you + + + align:start position:0% +operator that's fine by me right or you +could of course put everything with Vex + + align:start position:0% +could of course put everything with Vex + + + align:start position:0% +could of course put everything with Vex +if if you want to as well right so you + + align:start position:0% +if if you want to as well right so you + + + align:start position:0% +if if you want to as well right so you +can so your choices are you can write + + align:start position:0% +can so your choices are you can write + + + align:start position:0% +can so your choices are you can write +this this is the operator notation + + align:start position:0% + + + + align:start position:0% + +you could just write + + align:start position:0% +you could just write + + + align:start position:0% +you could just write +uh + + align:start position:0% +uh + + + align:start position:0% +uh +the same thing over here with a DX which + + align:start position:0% +the same thing over here with a DX which + + + align:start position:0% +the same thing over here with a DX which +is that this is the this is this is sort + + align:start position:0% +is that this is the this is this is sort + + + align:start position:0% +is that this is the this is this is sort +of Steven's notation + + align:start position:0% + + + + align:start position:0% + +I guess this is Alan's notation + + align:start position:0% +I guess this is Alan's notation + + + align:start position:0% +I guess this is Alan's notation +so you get you you get to pick + + align:start position:0% +so you get you you get to pick + + + align:start position:0% +so you get you you get to pick +and then finally most people's notation + + align:start position:0% +and then finally most people's notation + + + align:start position:0% +and then finally most people's notation +which I think is horrible is that the + + align:start position:0% +which I think is horrible is that the + + + align:start position:0% +which I think is horrible is that the +VEC + + align:start position:0% +VEC + + + align:start position:0% +VEC +if the X cubed is equal to all this + + align:start position:0% +if the X cubed is equal to all this + + + align:start position:0% +if the X cubed is equal to all this +times the VEC of DX + + align:start position:0% +times the VEC of DX + + + align:start position:0% +times the VEC of DX +so this is sort of the most standard + + align:start position:0% +so this is sort of the most standard + + + align:start position:0% +so this is sort of the most standard +notation + + align:start position:0% + + + + align:start position:0% + +okay so you get to take your pick + + align:start position:0% +okay so you get to take your pick + + + align:start position:0% +okay so you get to take your pick +there's no one right answer + + align:start position:0% + + + + align:start position:0% + +is it just did I write it in some other + + align:start position:0% +is it just did I write it in some other + + + align:start position:0% +is it just did I write it in some other +order + + align:start position:0% +order + + + align:start position:0% +order +I mean you know one plus two is two plus + + align:start position:0% +I mean you know one plus two is two plus + + + align:start position:0% +I mean you know one plus two is two plus +one kind of thing is that what we're + + align:start position:0% +one kind of thing is that what we're + + + align:start position:0% +one kind of thing is that what we're +talking about here yeah I've got the M + + align:start position:0% +talking about here yeah I've got the M + + + align:start position:0% +talking about here yeah I've got the M +squared on the right yeah I it's if you + + align:start position:0% +squared on the right yeah I it's if you + + + align:start position:0% +squared on the right yeah I it's if you +look at this one oh yeah I + + align:start position:0% +look at this one oh yeah I + + + align:start position:0% +look at this one oh yeah I +um yeah that doesn't matter though yeah + + align:start position:0% +um yeah that doesn't matter though yeah + + + align:start position:0% +um yeah that doesn't matter though yeah +yeah so + + align:start position:0% +yeah so + + + align:start position:0% +yeah so +um right or even up here + + align:start position:0% +um right or even up here + + + align:start position:0% +um right or even up here +uh + + align:start position:0% +uh + + + align:start position:0% +uh +yeah so but of course + + align:start position:0% +yeah so but of course + + + align:start position:0% +yeah so but of course +um uh uh it looks like you have e times + + align:start position:0% +um uh uh it looks like you have e times + + + align:start position:0% +um uh uh it looks like you have e times +M twice is one of those supposed to be M + + align:start position:0% +M twice is one of those supposed to be M + + + align:start position:0% +M twice is one of those supposed to be M +times M times Z oh + + align:start position:0% +times M times Z oh + + + align:start position:0% +times M times Z oh +how did that happen oh is that what you + + align:start position:0% +how did that happen oh is that what you + + + align:start position:0% +how did that happen oh is that what you +were noticing oh that's not good news + + align:start position:0% +were noticing oh that's not good news + + + align:start position:0% +were noticing oh that's not good news +how did I get the right answer + + align:start position:0% + + + + align:start position:0% + +oh you know I happen to pick an e that + + align:start position:0% +oh you know I happen to pick an e that + + + align:start position:0% +oh you know I happen to pick an e that +commuted with M which is probably not a + + align:start position:0% +commuted with M which is probably not a + + + align:start position:0% +commuted with M which is probably not a +good check + + align:start position:0% +good check + + + align:start position:0% +good check +you're oh my gosh that's exactly why I + + align:start position:0% +you're oh my gosh that's exactly why I + + + align:start position:0% +you're oh my gosh that's exactly why I +got the right answer don't ever tick so + + align:start position:0% +got the right answer don't ever tick so + + + align:start position:0% +got the right answer don't ever tick so +I didn't really have a good General test + + align:start position:0% +I didn't really have a good General test + + + align:start position:0% +I didn't really have a good General test +I see so let's yeah so let's another one + + align:start position:0% +I see so let's yeah so let's another one + + + align:start position:0% +I see so let's yeah so let's another one +below it looks like + + align:start position:0% +below it looks like + + + align:start position:0% +below it looks like +uh yeah I probably copied and pasted it + + align:start position:0% +uh yeah I probably copied and pasted it + + + align:start position:0% +uh yeah I probably copied and pasted it +you're right oh good catch + + align:start position:0% +you're right oh good catch + + + align:start position:0% +you're right oh good catch +thank you + + align:start position:0% +thank you + + + align:start position:0% +thank you +why did I do that + + align:start position:0% +why did I do that + + + align:start position:0% +why did I do that +so yeah so we should fix the thing + + align:start position:0% +so yeah so we should fix the thing + + + align:start position:0% +so yeah so we should fix the thing +online not just what I'm doing here so + + align:start position:0% +online not just what I'm doing here so + + + align:start position:0% +online not just what I'm doing here so +where did I Define e or + + align:start position:0% +where did I Define e or + + + align:start position:0% +where did I Define e or +well then I let's + + align:start position:0% +well then I let's + + + align:start position:0% +well then I let's +did he get to find earlier and earlier + + align:start position:0% +did he get to find earlier and earlier + + + align:start position:0% +did he get to find earlier and earlier +there's a way in Pluto + + align:start position:0% +there's a way in Pluto + + + align:start position:0% +there's a way in Pluto +to um + + align:start position:0% +to um + + + align:start position:0% +to um +if you you go below the E and I think + + align:start position:0% +if you you go below the E and I think + + + align:start position:0% +if you you go below the E and I think +you hit command or option oh command + + align:start position:0% +you hit command or option oh command + + + align:start position:0% +you hit command or option oh command +click to jump to the definition okay so + + align:start position:0% +click to jump to the definition okay so + + + align:start position:0% +click to jump to the definition okay so +let's see if I command click there's my + + align:start position:0% +let's see if I command click there's my + + + align:start position:0% +let's see if I command click there's my +okay so this is where yeah because it + + align:start position:0% +okay so this is where yeah because it + + + align:start position:0% +okay so this is where yeah because it +because he committed with them I got + + align:start position:0% +because he committed with them I got + + + align:start position:0% +because he committed with them I got +away with murder so let's do the + + align:start position:0% +away with murder so let's do the + + + align:start position:0% +away with murder so let's do the +following + + align:start position:0% +following + + + align:start position:0% +following +let's not do that let's go round of two + + align:start position:0% +let's not do that let's go round of two + + + align:start position:0% +let's not do that let's go round of two +two + + align:start position:0% +two + + + align:start position:0% +two +divided by one ten thousand or something + + align:start position:0% +divided by one ten thousand or something + + + align:start position:0% +divided by one ten thousand or something +so here's a perturbation okay and I'll + + align:start position:0% +so here's a perturbation okay and I'll + + + align:start position:0% +so here's a perturbation okay and I'll +point out that with this one I really + + align:start position:0% +point out that with this one I really + + + align:start position:0% +point out that with this one I really +did have the wrong answer and thank you + + align:start position:0% +did have the wrong answer and thank you + + + align:start position:0% +did have the wrong answer and thank you +for catching that + + align:start position:0% +for catching that + + + align:start position:0% +for catching that +so + + align:start position:0% +so + + + align:start position:0% +so +uh + + align:start position:0% +uh + + + align:start position:0% +uh +let's see so where where were we before + + align:start position:0% +let's see so where where were we before + + + align:start position:0% +let's see so where where were we before +we had all the wrong answers so here + + align:start position:0% +we had all the wrong answers so here + + + align:start position:0% +we had all the wrong answers so here +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +um so if I did this + + align:start position:0% +um so if I did this + + + align:start position:0% +um so if I did this +no actually it doesn't matter right here + + align:start position:0% +no actually it doesn't matter right here + + + align:start position:0% +no actually it doesn't matter right here +but if I did it over here + + align:start position:0% +but if I did it over here + + + align:start position:0% +but if I did it over here +so you see we're getting the right + + align:start position:0% +so you see we're getting the right + + + align:start position:0% +so you see we're getting the right +answer now + + align:start position:0% +answer now + + + align:start position:0% +answer now +but if I put back what I had at the + + align:start position:0% +but if I put back what I had at the + + + align:start position:0% +but if I put back what I had at the +beginning + + align:start position:0% +beginning + + + align:start position:0% +beginning +you'd see I'd have the wrong answer + + align:start position:0% +you'd see I'd have the wrong answer + + + align:start position:0% +you'd see I'd have the wrong answer +so it really did matter and I'm glad you + + align:start position:0% +so it really did matter and I'm glad you + + + align:start position:0% +so it really did matter and I'm glad you +found it + + align:start position:0% +found it + + + align:start position:0% +found it +okay + + align:start position:0% +okay + + + align:start position:0% +okay +nobody found that last year + + align:start position:0% +nobody found that last year + + + align:start position:0% +nobody found that last year +and I think I even showed this in + + align:start position:0% +and I think I even showed this in + + + align:start position:0% +and I think I even showed this in +another class + + align:start position:0% +another class + + + align:start position:0% +another class +so uh + + align:start position:0% +so uh + + + align:start position:0% +so uh +but I had a notebook that I showed for + + align:start position:0% +but I had a notebook that I showed for + + + align:start position:0% +but I had a notebook that I showed for +about four or five years until somebody + + align:start position:0% +about four or five years until somebody + + + align:start position:0% +about four or five years until somebody +found the mistake so we're doing better + + align:start position:0% +found the mistake so we're doing better + + + align:start position:0% +found the mistake so we're doing better +okay good any other questions + + align:start position:0% + + + + align:start position:0% + +about so + + align:start position:0% +about so + + + align:start position:0% +about so +all right so there all right let's move + + align:start position:0% +all right so there all right let's move + + + align:start position:0% +all right so there all right let's move +on to something that might seem a little + + align:start position:0% +on to something that might seem a little + + + align:start position:0% +on to something that might seem a little +bit kind of even more interesting + + align:start position:0% +bit kind of even more interesting + + + align:start position:0% +bit kind of even more interesting +something that I like to think of as a + + align:start position:0% +something that I like to think of as a + + + align:start position:0% +something that I like to think of as a +matrix function but you know however you + + align:start position:0% +matrix function but you know however you + + + align:start position:0% +matrix function but you know however you +want to think about it is fine the Lu + + align:start position:0% +want to think about it is fine the Lu + + + align:start position:0% +want to think about it is fine the Lu +decomposition + + align:start position:0% +decomposition + + + align:start position:0% +decomposition +okay so let's think about this for a + + align:start position:0% +okay so let's think about this for a + + + align:start position:0% +okay so let's think about this for a +minute does everybody know what Lu even + + align:start position:0% +minute does everybody know what Lu even + + + align:start position:0% +minute does everybody know what Lu even +means just to make sure so uh so the OU + + align:start position:0% +means just to make sure so uh so the OU + + + align:start position:0% +means just to make sure so uh so the OU +decomposition says that + + align:start position:0% +decomposition says that + + + align:start position:0% +decomposition says that +that a matrix + + align:start position:0% + + + + align:start position:0% + +which uh by the way it doesn't always + + align:start position:0% +which uh by the way it doesn't always + + + align:start position:0% +which uh by the way it doesn't always +exist but it kind of often exists a + + align:start position:0% +exist but it kind of often exists a + + + align:start position:0% +exist but it kind of often exists a +matrix a can be written + + align:start position:0% +matrix a can be written + + + align:start position:0% +matrix a can be written +as a + + align:start position:0% +as a + + + align:start position:0% +as a +unit lower triangular which means once + + align:start position:0% +unit lower triangular which means once + + + align:start position:0% +unit lower triangular which means once +on the diagonal + + align:start position:0% +on the diagonal + + + align:start position:0% +on the diagonal +times an upper triangular Matrix no + + align:start position:0% +times an upper triangular Matrix no + + + align:start position:0% +times an upper triangular Matrix no +assumptions about the diagonal okay and + + align:start position:0% +assumptions about the diagonal okay and + + + align:start position:0% +assumptions about the diagonal okay and +so this is called the Lu decomposition + + align:start position:0% +so this is called the Lu decomposition + + + align:start position:0% +so this is called the Lu decomposition +of a matrix and you've all you've all + + align:start position:0% +of a matrix and you've all you've all + + + align:start position:0% +of a matrix and you've all you've all +seen it you've all heard the word Lu + + align:start position:0% +seen it you've all heard the word Lu + + + align:start position:0% +seen it you've all heard the word Lu +it's it's equivalent to gaussian + + align:start position:0% +it's it's equivalent to gaussian + + + align:start position:0% +it's it's equivalent to gaussian +elimination + + align:start position:0% +elimination + + + align:start position:0% +elimination +okay and one thing that's worth pointing + + align:start position:0% +okay and one thing that's worth pointing + + + align:start position:0% +okay and one thing that's worth pointing +out is that if a is an N by n Matrix so + + align:start position:0% +out is that if a is an N by n Matrix so + + + align:start position:0% +out is that if a is an N by n Matrix so +it has N squared elements + + align:start position:0% +it has N squared elements + + + align:start position:0% +it has N squared elements +right if you look at sort of the the + + align:start position:0% +right if you look at sort of the the + + + align:start position:0% +right if you look at sort of the the +amount of memory you need that you know + + align:start position:0% +amount of memory you need that you know + + + align:start position:0% +amount of memory you need that you know +the number of numbers that you have to + + align:start position:0% +the number of numbers that you have to + + + align:start position:0% +the number of numbers that you have to +to write out L as a matrix what you need + + align:start position:0% +to write out L as a matrix what you need + + + align:start position:0% +to write out L as a matrix what you need +is well let's see how many numbers are + + align:start position:0% +is well let's see how many numbers are + + + align:start position:0% +is well let's see how many numbers are +there sitting inside of a I mean we + + align:start position:0% +there sitting inside of a I mean we + + + align:start position:0% +there sitting inside of a I mean we +don't care about the zeros like how many + + align:start position:0% +don't care about the zeros like how many + + + align:start position:0% +don't care about the zeros like how many +like numbers with information in them + + align:start position:0% +like numbers with information in them + + + align:start position:0% +like numbers with information in them +how many numbers are in a upper + + align:start position:0% +how many numbers are in a upper + + + align:start position:0% +how many numbers are in a upper +triangular n by n + + align:start position:0% + + + + align:start position:0% + +times n plus 1 over 2 exactly + + align:start position:0% +times n plus 1 over 2 exactly + + + align:start position:0% +times n plus 1 over 2 exactly +okay and then you know you don't even + + align:start position:0% +okay and then you know you don't even + + + align:start position:0% +okay and then you know you don't even +have to store the ones in fact uh uh uh + + align:start position:0% +have to store the ones in fact uh uh uh + + + align:start position:0% +have to store the ones in fact uh uh uh +all the linear algebra routines like La + + align:start position:0% +all the linear algebra routines like La + + + align:start position:0% +all the linear algebra routines like La +pack which is is what it's underneath + + align:start position:0% +pack which is is what it's underneath + + + align:start position:0% +pack which is is what it's underneath +Julia python or Matlab or whatever you + + align:start position:0% +Julia python or Matlab or whatever you + + + align:start position:0% +Julia python or Matlab or whatever you +like to use everybody's using the same + + align:start position:0% +like to use everybody's using the same + + + align:start position:0% +like to use everybody's using the same +La pack software under the hood they + + align:start position:0% +La pack software under the hood they + + + align:start position:0% +La pack software under the hood they +don't even store the ones because you + + align:start position:0% +don't even store the ones because you + + + align:start position:0% +don't even store the ones because you +don't have to right I mean why waste + + align:start position:0% +don't have to right I mean why waste + + + align:start position:0% +don't have to right I mean why waste +memory that you implicitly know it's a + + align:start position:0% +memory that you implicitly know it's a + + + align:start position:0% +memory that you implicitly know it's a +one so what are the number how many are + + align:start position:0% +one so what are the number how many are + + + align:start position:0% +one so what are the number how many are +there here that has information + + align:start position:0% + + + + align:start position:0% + +how many numbers on the outside + + align:start position:0% +how many numbers on the outside + + + align:start position:0% +how many numbers on the outside +sorry + + align:start position:0% +sorry + + + align:start position:0% +sorry +same but + + align:start position:0% +same but + + + align:start position:0% +same but +but a minus oh I like the way you said + + align:start position:0% +but a minus oh I like the way you said + + + align:start position:0% +but a minus oh I like the way you said +that the same but a minus okay n times n + + align:start position:0% +that the same but a minus okay n times n + + + align:start position:0% +that the same but a minus okay n times n +minus one over two good and if you add + + align:start position:0% +minus one over two good and if you add + + + align:start position:0% +minus one over two good and if you add +those two numbers up so if you I mean + + align:start position:0% +those two numbers up so if you I mean + + + align:start position:0% +those two numbers up so if you I mean +you can sort of do it visually if you + + align:start position:0% +you can sort of do it visually if you + + + align:start position:0% +you can sort of do it visually if you +like right you could + + align:start position:0% +like right you could + + + align:start position:0% +like right you could +add them up with you know this one's + + align:start position:0% +add them up with you know this one's + + + align:start position:0% +add them up with you know this one's +below the ones + + align:start position:0% +below the ones + + + align:start position:0% +below the ones +what do you what do you get + + align:start position:0% +what do you what do you get + + + align:start position:0% +what do you what do you get +you can visually add it visually or just + + align:start position:0% +you can visually add it visually or just + + + align:start position:0% +you can visually add it visually or just +do it algebraically whatever works for + + align:start position:0% +do it algebraically whatever works for + + + align:start position:0% +do it algebraically whatever works for +you + + align:start position:0% +you + + + align:start position:0% +you +what do you get + + align:start position:0% +what do you get + + + align:start position:0% +what do you get +N squared so + + align:start position:0% +N squared so + + + align:start position:0% +N squared so +I don't know if you ever stopped to + + align:start position:0% +I don't know if you ever stopped to + + + align:start position:0% +I don't know if you ever stopped to +think about this but the Lu + + align:start position:0% +think about this but the Lu + + + align:start position:0% +think about this but the Lu +decomposition is nothing other than a + + align:start position:0% +decomposition is nothing other than a + + + align:start position:0% +decomposition is nothing other than a +function from N squared variables to N + + align:start position:0% +function from N squared variables to N + + + align:start position:0% +function from N squared variables to N +squared variables right it's just a + + align:start position:0% +squared variables right it's just a + + + align:start position:0% +squared variables right it's just a +function from N squared variables to N + + align:start position:0% +function from N squared variables to N + + + align:start position:0% +function from N squared variables to N +squared variables and so therefore it + + align:start position:0% +squared variables and so therefore it + + + align:start position:0% +squared variables and so therefore it +has a Jacobian right it has a Jacobian + + align:start position:0% +has a Jacobian right it has a Jacobian + + + align:start position:0% +has a Jacobian right it has a Jacobian +that if you write it as a matrix will be + + align:start position:0% +that if you write it as a matrix will be + + + align:start position:0% +that if you write it as a matrix will be +N squared by N squared just as much as + + align:start position:0% +N squared by N squared just as much as + + + align:start position:0% +N squared by N squared just as much as +the Matrix square or Matrix Cube or the + + align:start position:0% +the Matrix square or Matrix Cube or the + + + align:start position:0% +the Matrix square or Matrix Cube or the +Matrix inverse function has a Jacobian + + align:start position:0% +Matrix inverse function has a Jacobian + + + align:start position:0% +Matrix inverse function has a Jacobian +that's N squared by N squared so does + + align:start position:0% +that's N squared by N squared so does + + + align:start position:0% +that's N squared by N squared so does +the Lu decomposition and in fact + + align:start position:0% +the Lu decomposition and in fact + + + align:start position:0% +the Lu decomposition and in fact +uh + + align:start position:0% +uh + + + align:start position:0% +uh +in fact here's the two by two version it + + align:start position:0% +in fact here's the two by two version it + + + align:start position:0% +in fact here's the two by two version it +gets more complicated when you go above + + align:start position:0% +gets more complicated when you go above + + + align:start position:0% +gets more complicated when you go above +two by two but here are L and U + + align:start position:0% +two by two but here are L and U + + + align:start position:0% +two by two but here are L and U +explicitly right so there's there so two + + align:start position:0% +explicitly right so there's there so two + + + align:start position:0% +explicitly right so there's there so two +by two Matrix has four elements and + + align:start position:0% +by two Matrix has four elements and + + + align:start position:0% +by two Matrix has four elements and +there's this one element in L and these + + align:start position:0% +there's this one element in L and these + + + align:start position:0% +there's this one element in L and these +three elements in U right and we could + + align:start position:0% +three elements in U right and we could + + + align:start position:0% +three elements in U right and we could +think of the Lu decomposition as + + align:start position:0% +think of the Lu decomposition as + + + align:start position:0% +think of the Lu decomposition as +the function from the four elements pqrs + + align:start position:0% +the function from the four elements pqrs + + + align:start position:0% +the function from the four elements pqrs +to these four numbers the the one in L + + align:start position:0% +to these four numbers the the one in L + + + align:start position:0% +to these four numbers the the one in L +and the three in U right so here's the + + align:start position:0% +and the three in U right so here's the + + + align:start position:0% +and the three in U right so here's the +oud composition in Julia just checking + + align:start position:0% +oud composition in Julia just checking + + + align:start position:0% +oud composition in Julia just checking +that L times U is is pqrs okay and so + + align:start position:0% +that L times U is is pqrs okay and so + + + align:start position:0% +that L times U is is pqrs okay and so +here are the four entries the the the + + align:start position:0% +here are the four entries the the the + + + align:start position:0% +here are the four entries the the the +the L entry over here and then the three + + align:start position:0% +the L entry over here and then the three + + + align:start position:0% +the L entry over here and then the three +U entries I'm just writing out and of + + align:start position:0% +U entries I'm just writing out and of + + + align:start position:0% +U entries I'm just writing out and of +course Julia would happily take the + + align:start position:0% +course Julia would happily take the + + + align:start position:0% +course Julia would happily take the +Jacobian of that function and give you + + align:start position:0% +Jacobian of that function and give you + + + align:start position:0% +Jacobian of that function and give you +the four by four Matrix Jacobian right + + align:start position:0% +the four by four Matrix Jacobian right + + + align:start position:0% +the four by four Matrix Jacobian right +and so I hope everybody remembers how + + align:start position:0% +and so I hope everybody remembers how + + + align:start position:0% +and so I hope everybody remembers how +this works I've said it a few times you + + align:start position:0% +this works I've said it a few times you + + + align:start position:0% +this works I've said it a few times you +take the first one Q over p and then + + align:start position:0% +take the first one Q over p and then + + + align:start position:0% +take the first one Q over p and then +take the respect to P that's minus Q + + align:start position:0% +take the respect to P that's minus Q + + + align:start position:0% +take the respect to P that's minus Q +over P Squared three respect to Q would + + align:start position:0% +over P Squared three respect to Q would + + + align:start position:0% +over P Squared three respect to Q would +be one over p and then there's no r or S + + align:start position:0% +be one over p and then there's no r or S + + + align:start position:0% +be one over p and then there's no r or S +here right and you can + + align:start position:0% +here right and you can + + + align:start position:0% +here right and you can +right and then you can do the same for + + align:start position:0% +right and then you can do the same for + + + align:start position:0% +right and then you can do the same for +the second third and fourth entry right + + align:start position:0% +the second third and fourth entry right + + + align:start position:0% +the second third and fourth entry right +so uh + + align:start position:0% +so uh + + + align:start position:0% +so uh +so + + align:start position:0% +so + + + align:start position:0% +so +so uh in fact I mean I'm writing this as + + align:start position:0% +so uh in fact I mean I'm writing this as + + + align:start position:0% +so uh in fact I mean I'm writing this as +an exercise but hopefully you can all + + align:start position:0% +an exercise but hopefully you can all + + + align:start position:0% +an exercise but hopefully you can all +see this this you can just do this with + + align:start position:0% +see this this you can just do this with + + + align:start position:0% +see this this you can just do this with +the product rule and get the right + + align:start position:0% +the product rule and get the right + + + align:start position:0% +the product rule and get the right +answer so dlu is going to be d o u plus + + align:start position:0% +answer so dlu is going to be d o u plus + + + align:start position:0% +answer so dlu is going to be d o u plus +ldu okay and did I write the answer here + + align:start position:0% +ldu okay and did I write the answer here + + + align:start position:0% +ldu okay and did I write the answer here +no all right I'll have you guys shout it + + align:start position:0% +no all right I'll have you guys shout it + + + align:start position:0% +no all right I'll have you guys shout it +out so let's see if you're kind of + + align:start position:0% +out so let's see if you're kind of + + + align:start position:0% +out so let's see if you're kind of +getting the hang of this chronic or + + align:start position:0% +getting the hang of this chronic or + + + align:start position:0% +getting the hang of this chronic or +product notation right and so the + + align:start position:0% +product notation right and so the + + + align:start position:0% +product notation right and so the +product rule says that dlu + + align:start position:0% +product rule says that dlu + + + align:start position:0% +product rule says that dlu +is going to equal l d u plus d l u or + + align:start position:0% +is going to equal l d u plus d l u or + + + align:start position:0% +is going to equal l d u plus d l u or +did I write it the other way not that it + + align:start position:0% +did I write it the other way not that it + + + align:start position:0% +did I write it the other way not that it +matters uh I wrote the other way it + + align:start position:0% +matters uh I wrote the other way it + + + align:start position:0% +matters uh I wrote the other way it +doesn't matter though plus d l u the + + align:start position:0% +doesn't matter though plus d l u the + + + align:start position:0% +doesn't matter though plus d l u the +thing that does matter is the L is + + align:start position:0% +thing that does matter is the L is + + + align:start position:0% +thing that does matter is the L is +always to the left of the U right it + + align:start position:0% +always to the left of the U right it + + + align:start position:0% +always to the left of the U right it +doesn't matter which term you write + + align:start position:0% +doesn't matter which term you write + + + align:start position:0% +doesn't matter which term you write +first though all right so anybody + + align:start position:0% +first though all right so anybody + + + align:start position:0% +first though all right so anybody +getting good at this what Chronicle + + align:start position:0% +getting good at this what Chronicle + + + align:start position:0% +getting good at this what Chronicle +product is this + + align:start position:0% + + + + align:start position:0% + +there's an i and an L or something + + align:start position:0% +there's an i and an L or something + + + align:start position:0% +there's an i and an L or something +this one will have an i and a u you + + align:start position:0% +this one will have an i and a u you + + + align:start position:0% +this one will have an i and a u you +getting good at it yet + + align:start position:0% +getting good at it yet + + + align:start position:0% +getting good at it yet +this one's iconica L and then this one + + align:start position:0% + + + + align:start position:0% + +what what what goes here what goes here + + align:start position:0% +what what what goes here what goes here + + + align:start position:0% +what what what goes here what goes here +U transverse Chronicle I exactly all + + align:start position:0% +U transverse Chronicle I exactly all + + + align:start position:0% +U transverse Chronicle I exactly all +right you guys are good right so you + + align:start position:0% +right you guys are good right so you + + + align:start position:0% +right you guys are good right so you +could write this like this and that I + + align:start position:0% +could write this like this and that I + + + align:start position:0% +could write this like this and that I +think is a perfectly good way to write + + align:start position:0% +think is a perfectly good way to write + + + align:start position:0% +think is a perfectly good way to write +down the Jacobian of course this is in + + align:start position:0% +down the Jacobian of course this is in + + + align:start position:0% +down the Jacobian of course this is in +Matrix form and it's not in separate + + align:start position:0% +Matrix form and it's not in separate + + + align:start position:0% +Matrix form and it's not in separate +form but it has all the right + + align:start position:0% +form but it has all the right + + + align:start position:0% +form but it has all the right +information yes + + align:start position:0% + + + + align:start position:0% + +yeah that gets a little tricky but + + align:start position:0% +yeah that gets a little tricky but + + + align:start position:0% +yeah that gets a little tricky but +yeah that does get a little tricky so + + align:start position:0% +yeah that does get a little tricky so + + + align:start position:0% +yeah that does get a little tricky so +I'm just gonna I'm just gonna say that + + align:start position:0% +I'm just gonna I'm just gonna say that + + + align:start position:0% +I'm just gonna I'm just gonna say that +is + + align:start position:0% +is + + + align:start position:0% +is +so the underlying Vector space is yeah + + align:start position:0% +so the underlying Vector space is yeah + + + align:start position:0% +so the underlying Vector space is yeah +yeah this is this is a little tricky so + + align:start position:0% +yeah this is this is a little tricky so + + + align:start position:0% +yeah this is this is a little tricky so +that + + align:start position:0% +that + + + align:start position:0% +that +that I'm I like to think of the DL uh + + align:start position:0% +that I'm I like to think of the DL uh + + + align:start position:0% +that I'm I like to think of the DL uh +zero zero zero and then + + align:start position:0% +zero zero zero and then + + + align:start position:0% +zero zero zero and then +dl21 after all + + align:start position:0% +dl21 after all + + + align:start position:0% +dl21 after all +the ones the derivative of the ones on + + align:start position:0% +the ones the derivative of the ones on + + + align:start position:0% +the ones the derivative of the ones on +the diagonal zero and then everything + + align:start position:0% +the diagonal zero and then everything + + + align:start position:0% +the diagonal zero and then everything +else is zero anyway right and the D U is + + align:start position:0% +else is zero anyway right and the D U is + + + align:start position:0% +else is zero anyway right and the D U is +a zero d u one one d u one two and du22 + + align:start position:0% +a zero d u one one d u one two and du22 + + + align:start position:0% +a zero d u one one d u one two and du22 +right so in some sense if you really + + align:start position:0% +right so in some sense if you really + + + align:start position:0% +right so in some sense if you really +wanted to do it the standard notation + + align:start position:0% +wanted to do it the standard notation + + + align:start position:0% +wanted to do it the standard notation +the way the one that would be like this + + align:start position:0% +the way the one that would be like this + + + align:start position:0% +the way the one that would be like this +you would have to write down + + align:start position:0% +you would have to write down + + + align:start position:0% +you would have to write down +you you would have to write down + + align:start position:0% +you you would have to write down + + + align:start position:0% +you you would have to write down +something that worked with the l21 and + + align:start position:0% +something that worked with the l21 and + + + align:start position:0% +something that worked with the l21 and +du11 + + align:start position:0% +du11 + + + align:start position:0% +du11 +du12 and du22 but again I feel like + + align:start position:0% +du12 and du22 but again I feel like + + + align:start position:0% +du12 and du22 but again I feel like +that's + + align:start position:0% +that's + + + align:start position:0% +that's +that's just like following the crowd + + align:start position:0% +that's just like following the crowd + + + align:start position:0% +that's just like following the crowd +right me I would rather just say that I + + align:start position:0% +right me I would rather just say that I + + + align:start position:0% +right me I would rather just say that I +understand that my Vector space consists + + align:start position:0% +understand that my Vector space consists + + + align:start position:0% +understand that my Vector space consists +of lower triangular perturbations to L + + align:start position:0% +of lower triangular perturbations to L + + + align:start position:0% +of lower triangular perturbations to L +and upper triangle perturbations to U + + align:start position:0% +and upper triangle perturbations to U + + + align:start position:0% +and upper triangle perturbations to U +and so let's just look at it that way + + align:start position:0% +and so let's just look at it that way + + + align:start position:0% +and so let's just look at it that way +okay and that's that's kind of how I + + align:start position:0% +okay and that's that's kind of how I + + + align:start position:0% +okay and that's that's kind of how I +like to see it but maybe that's maybe + + align:start position:0% +like to see it but maybe that's maybe + + + align:start position:0% +like to see it but maybe that's maybe +I'm pushing the notation too far maybe + + align:start position:0% +I'm pushing the notation too far maybe + + + align:start position:0% +I'm pushing the notation too far maybe +you would prefer you know maybe for the + + align:start position:0% +you would prefer you know maybe for the + + + align:start position:0% +you would prefer you know maybe for the +purposes of this class I would be better + + align:start position:0% +purposes of this class I would be better + + + align:start position:0% +purposes of this class I would be better +off + + align:start position:0% +off + + + align:start position:0% +off +doing it like this + + align:start position:0% +doing it like this + + + align:start position:0% +doing it like this +but even this is slightly yeah maybe + + align:start position:0% +but even this is slightly yeah maybe + + + align:start position:0% +but even this is slightly yeah maybe +that would be better for now + + align:start position:0% +that would be better for now + + + align:start position:0% +that would be better for now +but you see I like to put all my + + align:start position:0% +but you see I like to put all my + + + align:start position:0% +but you see I like to put all my +perturbations on the right so again + + align:start position:0% +perturbations on the right so again + + + align:start position:0% +perturbations on the right so again +there's nobody's fully standardized all + + align:start position:0% +there's nobody's fully standardized all + + + align:start position:0% +there's nobody's fully standardized all +this notation so once again you have + + align:start position:0% +this notation so once again you have + + + align:start position:0% +this notation so once again you have +your choice + + align:start position:0% +your choice + + + align:start position:0% +your choice +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so here I'll show you just a couple of + + align:start position:0% +so here I'll show you just a couple of + + + align:start position:0% +so here I'll show you just a couple of +more Matrix factorizations just quickly + + align:start position:0% +more Matrix factorizations just quickly + + + align:start position:0% +more Matrix factorizations just quickly +I'm not going to go into too much detail + + align:start position:0% +I'm not going to go into too much detail + + + align:start position:0% +I'm not going to go into too much detail +but I want you to just see that that you + + align:start position:0% +but I want you to just see that that you + + + align:start position:0% +but I want you to just see that that you +know you can still do this for other + + align:start position:0% +know you can still do this for other + + + align:start position:0% +know you can still do this for other +situations so one favorite of mine is a + + align:start position:0% +situations so one favorite of mine is a + + + align:start position:0% +situations so one favorite of mine is a +two parameter example + + align:start position:0% +two parameter example + + + align:start position:0% +two parameter example +um in you know two by two matrices have + + align:start position:0% +um in you know two by two matrices have + + + align:start position:0% +um in you know two by two matrices have +four parameters but but there's only two + + align:start position:0% +four parameters but but there's only two + + + align:start position:0% +four parameters but but there's only two +real parameters here which uh uh a + + align:start position:0% +real parameters here which uh uh a + + + align:start position:0% +real parameters here which uh uh a +traceless symmetric matrices so the fact + + align:start position:0% +traceless symmetric matrices so the fact + + + align:start position:0% +traceless symmetric matrices so the fact +that the Matrix two by two Matrix is + + align:start position:0% +that the Matrix two by two Matrix is + + + align:start position:0% +that the Matrix two by two Matrix is +symmetric means you have the S over here + + align:start position:0% +symmetric means you have the S over here + + + align:start position:0% +symmetric means you have the S over here +and over here and the fact that it's + + align:start position:0% +and over here and the fact that it's + + + align:start position:0% +and over here and the fact that it's +traceless is says that the trace is zero + + align:start position:0% +traceless is says that the trace is zero + + + align:start position:0% +traceless is says that the trace is zero +right so if you have a p over here you + + align:start position:0% +right so if you have a p over here you + + + align:start position:0% +right so if you have a p over here you +need a minus P to make the sum of the + + align:start position:0% +need a minus P to make the sum of the + + + align:start position:0% +need a minus P to make the sum of the +diagonal zero okay and so this is a two + + align:start position:0% +diagonal zero okay and so this is a two + + + align:start position:0% +diagonal zero okay and so this is a two +parameter family and this is by the way + + align:start position:0% +parameter family and this is by the way + + + align:start position:0% +parameter family and this is by the way +the queue that showed up on top right so + + align:start position:0% +the queue that showed up on top right so + + + align:start position:0% +the queue that showed up on top right so +uh if you if you write down you all know + + align:start position:0% +uh if you if you write down you all know + + + align:start position:0% +uh if you if you write down you all know +that symmetric matrices have orthogonal + + align:start position:0% +that symmetric matrices have orthogonal + + + align:start position:0% +that symmetric matrices have orthogonal +eigenvectors so you can write it with + + align:start position:0% +eigenvectors so you can write it with + + + align:start position:0% +eigenvectors so you can write it with +cosines and Sines and as a little bit of + + align:start position:0% +cosines and Sines and as a little bit of + + + align:start position:0% +cosines and Sines and as a little bit of +setup I'm using one half Theta as as + + align:start position:0% +setup I'm using one half Theta as as + + + align:start position:0% +setup I'm using one half Theta as as +opposed to just using Theta okay and + + align:start position:0% +opposed to just using Theta okay and + + + align:start position:0% +opposed to just using Theta okay and +and here's my eigenvalues The eigenvalue + + align:start position:0% +and here's my eigenvalues The eigenvalue + + + align:start position:0% +and here's my eigenvalues The eigenvalue +Matrix + + align:start position:0% +Matrix + + + align:start position:0% +Matrix +the only thing that we know about the + + align:start position:0% +the only thing that we know about the + + + align:start position:0% +the only thing that we know about the +eigenvalue Matrix for starters is is + + align:start position:0% +eigenvalue Matrix for starters is is + + + align:start position:0% +eigenvalue Matrix for starters is is +that the sum of the eigenvalues are zero + + align:start position:0% +that the sum of the eigenvalues are zero + + + align:start position:0% +that the sum of the eigenvalues are zero +so let's call this the positive one and + + align:start position:0% +so let's call this the positive one and + + + align:start position:0% +so let's call this the positive one and +this the negative one okay and + + align:start position:0% +this the negative one okay and + + + align:start position:0% +this the negative one okay and +what what we have to equate is this is + + align:start position:0% +what what we have to equate is this is + + + align:start position:0% +what what we have to equate is this is +the eigen decomposition right so uh so + + align:start position:0% +the eigen decomposition right so uh so + + + align:start position:0% +the eigen decomposition right so uh so +so so you know these two are equal these + + align:start position:0% +so so you know these two are equal these + + + align:start position:0% +so so you know these two are equal these +two are opposite And So It all becomes + + align:start position:0% +two are opposite And So It all becomes + + + align:start position:0% +two are opposite And So It all becomes +let's see if we can get this right here + + align:start position:0% +let's see if we can get this right here + + + align:start position:0% +let's see if we can get this right here +um + + align:start position:0% +um + + + align:start position:0% +um +yeah so so this is the Matrix + + align:start position:0% +yeah so so this is the Matrix + + + align:start position:0% +yeah so so this is the Matrix +okay and um this is the Matrix has two + + align:start position:0% +okay and um this is the Matrix has two + + + align:start position:0% +okay and um this is the Matrix has two +parameters P and S the eigen + + align:start position:0% +parameters P and S the eigen + + + align:start position:0% +parameters P and S the eigen +decomposition has two parameters maybe I + + align:start position:0% +decomposition has two parameters maybe I + + + align:start position:0% +decomposition has two parameters maybe I +should have emphasized that so the + + align:start position:0% +should have emphasized that so the + + + align:start position:0% +should have emphasized that so the +eigenvectors have one parameter Theta + + align:start position:0% +eigenvectors have one parameter Theta + + + align:start position:0% +eigenvectors have one parameter Theta +and the eigenvalue has one parameter R + + align:start position:0% +and the eigenvalue has one parameter R + + + align:start position:0% +and the eigenvalue has one parameter R +right so so the eigen decomposition here + + align:start position:0% +right so so the eigen decomposition here + + + align:start position:0% +right so so the eigen decomposition here +this little two by two eigen + + align:start position:0% +this little two by two eigen + + + align:start position:0% +this little two by two eigen +decomposition is a map from the two + + align:start position:0% +decomposition is a map from the two + + + align:start position:0% +decomposition is a map from the two +variables PS to the two variables R + + align:start position:0% +variables PS to the two variables R + + + align:start position:0% +variables PS to the two variables R +Theta right and Computing the + + align:start position:0% +Theta right and Computing the + + + align:start position:0% +Theta right and Computing the +eigenvalues of this two by two Matrix is + + align:start position:0% +eigenvalues of this two by two Matrix is + + + align:start position:0% +eigenvalues of this two by two Matrix is +just a map from R2 to R2 + + align:start position:0% +just a map from R2 to R2 + + + align:start position:0% +just a map from R2 to R2 +okay and we can get the Jacobian and + + align:start position:0% +okay and we can get the Jacobian and + + + align:start position:0% +okay and we can get the Jacobian and +here's the Jacobian of that map right so + + align:start position:0% +here's the Jacobian of that map right so + + + align:start position:0% +here's the Jacobian of that map right so +this is the actual two by two Jacobian + + align:start position:0% +this is the actual two by two Jacobian + + + align:start position:0% +this is the actual two by two Jacobian +of of that and sometimes it's fun to + + align:start position:0% +of of that and sometimes it's fun to + + + align:start position:0% +of of that and sometimes it's fun to +compute the Jacobian determinant which + + align:start position:0% +compute the Jacobian determinant which + + + align:start position:0% +compute the Jacobian determinant which +is r in this case + + align:start position:0% +is r in this case + + + align:start position:0% +is r in this case +and some of you might recognize that + + align:start position:0% +and some of you might recognize that + + + align:start position:0% +and some of you might recognize that +this eigen decomposition change of + + align:start position:0% +this eigen decomposition change of + + + align:start position:0% +this eigen decomposition change of +coordinates is exactly the same + + align:start position:0% +coordinates is exactly the same + + + align:start position:0% +coordinates is exactly the same +mathematical change of coordinates of + + align:start position:0% +mathematical change of coordinates of + + + align:start position:0% +mathematical change of coordinates of +going from Cartesian to Polar + + align:start position:0% +going from Cartesian to Polar + + + align:start position:0% +going from Cartesian to Polar +coordinates + + align:start position:0% +coordinates + + + align:start position:0% +coordinates +okay and this determinant R is exactly + + align:start position:0% +okay and this determinant R is exactly + + + align:start position:0% +okay and this determinant R is exactly +the so you know many of you probably + + align:start position:0% +the so you know many of you probably + + + align:start position:0% +the so you know many of you probably +memorized that that the area element in + + align:start position:0% +memorized that that the area element in + + + align:start position:0% +memorized that that the area element in +Cartesian coordinates the x d y is rdrd + + align:start position:0% +Cartesian coordinates the x d y is rdrd + + + align:start position:0% +Cartesian coordinates the x d y is rdrd +Theta well here's we just we just in + + align:start position:0% +Theta well here's we just we just in + + + align:start position:0% +Theta well here's we just we just in +effect let let Julia derive that for us + + align:start position:0% +effect let let Julia derive that for us + + + align:start position:0% +effect let let Julia derive that for us +okay but let's go further I'll do one + + align:start position:0% +okay but let's go further I'll do one + + + align:start position:0% +okay but let's go further I'll do one +more example + + align:start position:0% +more example + + + align:start position:0% +more example +the full two by two symmetric eigen + + align:start position:0% +the full two by two symmetric eigen + + + align:start position:0% +the full two by two symmetric eigen +problem but any questions about + + align:start position:0% +problem but any questions about + + + align:start position:0% +problem but any questions about +about this sort of restricted eigen + + align:start position:0% +about this sort of restricted eigen + + + align:start position:0% +about this sort of restricted eigen +problem + + align:start position:0% +problem + + + align:start position:0% +problem +it's a map from R2 to R2 and it's + + align:start position:0% +it's a map from R2 to R2 and it's + + + align:start position:0% +it's a map from R2 to R2 and it's +exactly the map it's exactly the map + + align:start position:0% +exactly the map it's exactly the map + + + align:start position:0% +exactly the map it's exactly the map +that's why I chose the Theta over two + + align:start position:0% +that's why I chose the Theta over two + + + align:start position:0% +that's why I chose the Theta over two +it's exactly the map from Cartesian to + + align:start position:0% +it's exactly the map from Cartesian to + + + align:start position:0% +it's exactly the map from Cartesian to +corn to Polar coordinates by I don't + + align:start position:0% +corn to Polar coordinates by I don't + + + align:start position:0% +corn to Polar coordinates by I don't +know whether you call that a coincidence + + align:start position:0% +know whether you call that a coincidence + + + align:start position:0% +know whether you call that a coincidence +or what but I think it's intriguing that + + align:start position:0% +or what but I think it's intriguing that + + + align:start position:0% +or what but I think it's intriguing that +it's the same map all right let's do the + + align:start position:0% +it's the same map all right let's do the + + + align:start position:0% +it's the same map all right let's do the +full symmetric + + align:start position:0% +full symmetric + + + align:start position:0% +full symmetric +so in the so the full case a symmetric + + align:start position:0% +so in the so the full case a symmetric + + + align:start position:0% +so in the so the full case a symmetric +Matrix is a three-dimensional Vector + + align:start position:0% +Matrix is a three-dimensional Vector + + + align:start position:0% +Matrix is a three-dimensional Vector +space right so you've got three three + + align:start position:0% +space right so you've got three three + + + align:start position:0% +space right so you've got three three +parameters right the the two diagonals + + align:start position:0% +parameters right the the two diagonals + + + align:start position:0% +parameters right the the two diagonals +and then the the off diagonals are the + + align:start position:0% +and then the the off diagonals are the + + + align:start position:0% +and then the the off diagonals are the +same number so we can refer to every + + align:start position:0% +same number so we can refer to every + + + align:start position:0% +same number so we can refer to every +three two by two symmetric Matrix with + + align:start position:0% +three two by two symmetric Matrix with + + + align:start position:0% +three two by two symmetric Matrix with +the variables p r and s + + align:start position:0% +the variables p r and s + + + align:start position:0% +the variables p r and s +right and the the three variables are + + align:start position:0% +right and the the three variables are + + + align:start position:0% +right and the the three variables are +since the Matrix symmetric Matrix has + + align:start position:0% +since the Matrix symmetric Matrix has + + + align:start position:0% +since the Matrix symmetric Matrix has +has an orthogonal eigenvectors you still + + align:start position:0% +has an orthogonal eigenvectors you still + + + align:start position:0% +has an orthogonal eigenvectors you still +have one parameter Theta for the + + align:start position:0% +have one parameter Theta for the + + + align:start position:0% +have one parameter Theta for the +eigenvectors but we have two parameters + + align:start position:0% +eigenvectors but we have two parameters + + + align:start position:0% +eigenvectors but we have two parameters +Lambda one and Lambda 2 for the + + align:start position:0% +Lambda one and Lambda 2 for the + + + align:start position:0% +Lambda one and Lambda 2 for the +eigenvalues okay and so the symmetric + + align:start position:0% +eigenvalues okay and so the symmetric + + + align:start position:0% +eigenvalues okay and so the symmetric +eigenvalue problem is once again mapping + + align:start position:0% +eigenvalue problem is once again mapping + + + align:start position:0% +eigenvalue problem is once again mapping +this time from R3 to R3 right you can go + + align:start position:0% +this time from R3 to R3 right you can go + + + align:start position:0% +this time from R3 to R3 right you can go +backwards and forwards you can go from + + align:start position:0% +backwards and forwards you can go from + + + align:start position:0% +backwards and forwards you can go from +the eigenvalues and eigenvectors to The + + align:start position:0% +the eigenvalues and eigenvectors to The + + + align:start position:0% +the eigenvalues and eigenvectors to The +Matrix which by the way is the more + + align:start position:0% +Matrix which by the way is the more + + + align:start position:0% +Matrix which by the way is the more +convenient direction or you can go from + + align:start position:0% +convenient direction or you can go from + + + align:start position:0% +convenient direction or you can go from +The Matrix entries to the eigenvalues + + align:start position:0% +The Matrix entries to the eigenvalues + + + align:start position:0% +The Matrix entries to the eigenvalues +and eigenvectors right and so everybody + + align:start position:0% +and eigenvectors right and so everybody + + + align:start position:0% +and eigenvectors right and so everybody +in first year linear algebra learns how + + align:start position:0% +in first year linear algebra learns how + + + align:start position:0% +in first year linear algebra learns how +to go this way + + align:start position:0% +to go this way + + + align:start position:0% +to go this way +right you you you compute you've set up + + align:start position:0% +right you you you compute you've set up + + + align:start position:0% +right you you you compute you've set up +the characteristic polynomial you write + + align:start position:0% +the characteristic polynomial you write + + + align:start position:0% +the characteristic polynomial you write +down the quadratic you solve it right + + align:start position:0% +down the quadratic you solve it right + + + align:start position:0% +down the quadratic you solve it right +and you know in one way or another you + + align:start position:0% +and you know in one way or another you + + + align:start position:0% +and you know in one way or another you +can get the eigenvector as well + + align:start position:0% +can get the eigenvector as well + + + align:start position:0% +can get the eigenvector as well +um so you know you you look at the null + + align:start position:0% +um so you know you you look at the null + + + align:start position:0% +um so you know you you look at the null +space of a minus Lambda I or something + + align:start position:0% +space of a minus Lambda I or something + + + align:start position:0% +space of a minus Lambda I or something +right so this is this left Direction + + align:start position:0% +right so this is this left Direction + + + align:start position:0% +right so this is this left Direction +you've all done in your first year + + align:start position:0% +you've all done in your first year + + + align:start position:0% +you've all done in your first year +linear algebra class turns out it's a + + align:start position:0% +linear algebra class turns out it's a + + + align:start position:0% +linear algebra class turns out it's a +little more convenient to go the other + + align:start position:0% +little more convenient to go the other + + + align:start position:0% +little more convenient to go the other +way this is just a matrix multiply where + + align:start position:0% +way this is just a matrix multiply where + + + align:start position:0% +way this is just a matrix multiply where +I set up the eigenvalues and + + align:start position:0% +I set up the eigenvalues and + + + align:start position:0% +I set up the eigenvalues and +eigenvectors and then I compute The + + align:start position:0% +eigenvectors and then I compute The + + + align:start position:0% +eigenvectors and then I compute The +Matrix okay and so here is the Jacobian + + align:start position:0% +Matrix okay and so here is the Jacobian + + + align:start position:0% +Matrix okay and so here is the Jacobian +calculation so it's a three by three + + align:start position:0% +calculation so it's a three by three + + + align:start position:0% +calculation so it's a three by three +Jacobian there it is in all of its Glory + + align:start position:0% +Jacobian there it is in all of its Glory + + + align:start position:0% +Jacobian there it is in all of its Glory +a little bit painful to do by hand but + + align:start position:0% +a little bit painful to do by hand but + + + align:start position:0% +a little bit painful to do by hand but +completely doable Julia of course just + + align:start position:0% +completely doable Julia of course just + + + align:start position:0% +completely doable Julia of course just +happily gives you the answer without all + + align:start position:0% +happily gives you the answer without all + + + align:start position:0% +happily gives you the answer without all +the hard work + + align:start position:0% +the hard work + + + align:start position:0% +the hard work +and I'll just mention that if you + + align:start position:0% +and I'll just mention that if you + + + align:start position:0% +and I'll just mention that if you +calculate the determinants of this + + align:start position:0% +calculate the determinants of this + + + align:start position:0% +calculate the determinants of this +Matrix so you you get you sort of get + + align:start position:0% +Matrix so you you get you sort of get + + + align:start position:0% +Matrix so you you get you sort of get +the the the the volume element right so + + align:start position:0% +the the the the volume element right so + + + align:start position:0% +the the the the volume element right so +just to make sure everybody knows how + + align:start position:0% +just to make sure everybody knows how + + + align:start position:0% +just to make sure everybody knows how +that works the volume of the Jacobian is + + align:start position:0% +that works the volume of the Jacobian is + + + align:start position:0% +that works the volume of the Jacobian is +how much + + align:start position:0% +how much + + + align:start position:0% +how much +a little Cube scales right like if I go + + align:start position:0% +a little Cube scales right like if I go + + + align:start position:0% +a little Cube scales right like if I go +back to that picture of the Corgi being + + align:start position:0% +back to that picture of the Corgi being + + + align:start position:0% +back to that picture of the Corgi being +warped right I could look at his nose + + align:start position:0% +warped right I could look at his nose + + + align:start position:0% +warped right I could look at his nose +and um and then in the image you know + + align:start position:0% +and um and then in the image you know + + + align:start position:0% +and um and then in the image you know +maybe it gets squashed the the ratio is + + align:start position:0% +maybe it gets squashed the the ratio is + + + align:start position:0% +maybe it gets squashed the the ratio is +is the determinants of the + + align:start position:0% +is the determinants of the + + + align:start position:0% +is the determinants of the +transformation it's actually determined + + align:start position:0% +transformation it's actually determined + + + align:start position:0% +transformation it's actually determined +of the Jacobian right and if you do that + + align:start position:0% +of the Jacobian right and if you do that + + + align:start position:0% +of the Jacobian right and if you do that +you actually get Lambda 1 minus two + + align:start position:0% +you actually get Lambda 1 minus two + + + align:start position:0% +you actually get Lambda 1 minus two +Lambda 2 and uh people like to say that + + align:start position:0% +Lambda 2 and uh people like to say that + + + align:start position:0% +Lambda 2 and uh people like to say that +symmetric I get that eigenvalues don't + + align:start position:0% +symmetric I get that eigenvalues don't + + + align:start position:0% +symmetric I get that eigenvalues don't +wanna so so so if the determinant being + + align:start position:0% +wanna so so so if the determinant being + + + align:start position:0% +wanna so so so if the determinant being +Lambda one minus Lambda 2 is an + + align:start position:0% +Lambda one minus Lambda 2 is an + + + align:start position:0% +Lambda one minus Lambda 2 is an +indication of repulsion between + + align:start position:0% +indication of repulsion between + + + align:start position:0% +indication of repulsion between +eigenvalues but maybe that's neither + + align:start position:0% +eigenvalues but maybe that's neither + + + align:start position:0% +eigenvalues but maybe that's neither +here nor there all right well I think my + + align:start position:0% +here nor there all right well I think my + + + align:start position:0% +here nor there all right well I think my +timing is perfect I went through this + + align:start position:0% +timing is perfect I went through this + + + align:start position:0% +timing is perfect I went through this +notebook and it's 1201 exactly so should + + align:start position:0% +notebook and it's 1201 exactly so should + + + align:start position:0% +notebook and it's 1201 exactly so should +we take the five minute break and then + + align:start position:0% +we take the five minute break and then + + + align:start position:0% +we take the five minute break and then +Steven you'll be on board for the next + + align:start position:0% +Steven you'll be on board for the next + + + align:start position:0% +Steven you'll be on board for the next +certain stuff + + align:start position:0% +certain stuff + + + align:start position:0% +certain stuff +all right so 1206 come on back we'll + + align:start position:0% +all right so 1206 come on back we'll + + + align:start position:0% +all right so 1206 come on back we'll +start up again \ No newline at end of file diff --git a/BUnUOv_INyM.txt b/BUnUOv_INyM.txt new file mode 100644 index 0000000000000000000000000000000000000000..5db763d17ab6df36012257727bae2ae01194fa3a --- /dev/null +++ b/BUnUOv_INyM.txt @@ -0,0 +1,9419 @@ +align:start position:0% + +today what we're gonna do is continue + + align:start position:0% +today what we're gonna do is continue + + + align:start position:0% +today what we're gonna do is continue +our discussion of factor markets by + + align:start position:0% +our discussion of factor markets by + + + align:start position:0% +our discussion of factor markets by +essentially talking about how capital + + align:start position:0% +essentially talking about how capital + + + align:start position:0% +essentially talking about how capital +markets impact real-world decisions so + + align:start position:0% +markets impact real-world decisions so + + + align:start position:0% +markets impact real-world decisions so +last time we talked about the capital + + align:start position:0% +last time we talked about the capital + + + align:start position:0% +last time we talked about the capital +market we talked about essentially the + + align:start position:0% +market we talked about essentially the + + + align:start position:0% +market we talked about essentially the +way that firms finance their capital is + + align:start position:0% +way that firms finance their capital is + + + align:start position:0% +way that firms finance their capital is +by going to a pool of savings that + + align:start position:0% +by going to a pool of savings that + + + align:start position:0% +by going to a pool of savings that +individuals decide and how much to make + + align:start position:0% +individuals decide and how much to make + + + align:start position:0% +individuals decide and how much to make +individuals make an inter temporal + + align:start position:0% +individuals make an inter temporal + + + align:start position:0% +individuals make an inter temporal +choice on how much to save actually + + align:start position:0% +choice on how much to save actually + + + align:start position:0% +choice on how much to save actually +technically make an internal choice + + align:start position:0% +technically make an internal choice + + + align:start position:0% +technically make an internal choice +about how much to consume each period + + align:start position:0% +about how much to consume each period + + + align:start position:0% +about how much to consume each period +that then yields an amount of savings + + align:start position:0% +that then yields an amount of savings + + + align:start position:0% +that then yields an amount of savings +and then based on that pool of savings + + align:start position:0% +and then based on that pool of savings + + + align:start position:0% +and then based on that pool of savings +firms borrow with some interest rate I + + align:start position:0% +firms borrow with some interest rate I + + + align:start position:0% +firms borrow with some interest rate I +and they decide how much to invest now + + align:start position:0% +and they decide how much to invest now + + + align:start position:0% +and they decide how much to invest now +today we're going to talk about a number + + align:start position:0% +today we're going to talk about a number + + + align:start position:0% +today we're going to talk about a number +of interesting applications that arise + + align:start position:0% +of interesting applications that arise + + + align:start position:0% +of interesting applications that arise +from capital markets that are important + + align:start position:0% +from capital markets that are important + + + align:start position:0% +from capital markets that are important +in the real world I'm going to start by + + align:start position:0% +in the real world I'm going to start by + + + align:start position:0% +in the real world I'm going to start by +talking about the concept of present + + align:start position:0% +talking about the concept of present + + + align:start position:0% +talking about the concept of present +value present value now the key insight + + align:start position:0% +value present value now the key insight + + + align:start position:0% +value present value now the key insight +when we think about capital markets is + + align:start position:0% +when we think about capital markets is + + + align:start position:0% +when we think about capital markets is +that a dollar tomorrow is worth less + + align:start position:0% +that a dollar tomorrow is worth less + + + align:start position:0% +that a dollar tomorrow is worth less +than a dollar today a dollar tomorrow is + + align:start position:0% +than a dollar today a dollar tomorrow is + + + align:start position:0% +than a dollar today a dollar tomorrow is +worth less than dollars a that's because + + align:start position:0% +worth less than dollars a that's because + + + align:start position:0% +worth less than dollars a that's because +if you had the dollar today you could + + align:start position:0% +if you had the dollar today you could + + + align:start position:0% +if you had the dollar today you could +productively invest it and have more + + align:start position:0% +productively invest it and have more + + + align:start position:0% +productively invest it and have more +than a dollar tomorrow so in Davos a is + + align:start position:0% +than a dollar tomorrow so in Davos a is + + + align:start position:0% +than a dollar tomorrow so in Davos a is +worth more because you could do + + align:start position:0% +worth more because you could do + + + align:start position:0% +worth more because you could do +something productive with that dollar if + + align:start position:0% +something productive with that dollar if + + + align:start position:0% +something productive with that dollar if +you had it today okay what that means is + + align:start position:0% +you had it today okay what that means is + + + align:start position:0% +you had it today okay what that means is +that dollars in different periods are + + align:start position:0% +that dollars in different periods are + + + align:start position:0% +that dollars in different periods are +worth different things you can't just + + align:start position:0% +worth different things you can't just + + + align:start position:0% +worth different things you can't just +add them up + + align:start position:0% +add them up + + + align:start position:0% +add them up +okay the analogy I like is thinking + + align:start position:0% +okay the analogy I like is thinking + + + align:start position:0% +okay the analogy I like is thinking +about imagine you had a pound of apples + + align:start position:0% +about imagine you had a pound of apples + + + align:start position:0% +about imagine you had a pound of apples +a pound of steak and a pound of gold you + + align:start position:0% +a pound of steak and a pound of gold you + + + align:start position:0% +a pound of steak and a pound of gold you +wouldn't just add them up and say I have + + align:start position:0% +wouldn't just add them up and say I have + + + align:start position:0% +wouldn't just add them up and say I have +three pounds that'd be useless you'd + + align:start position:0% +three pounds that'd be useless you'd + + + align:start position:0% +three pounds that'd be useless you'd +want to know what each is worth it you + + align:start position:0% +want to know what each is worth it you + + + align:start position:0% +want to know what each is worth it you +want to add up the dollar value of them + + align:start position:0% +want to add up the dollar value of them + + + align:start position:0% +want to add up the dollar value of them +okay it's a similar thing with money + + align:start position:0% +okay it's a similar thing with money + + + align:start position:0% +okay it's a similar thing with money +received over time you can't just say + + align:start position:0% +received over time you can't just say + + + align:start position:0% +received over time you can't just say +I'm getting a dollar today a dollar next + + align:start position:0% +I'm getting a dollar today a dollar next + + + align:start position:0% +I'm getting a dollar today a dollar next +year and a dollar five years from now + + align:start position:0% +year and a dollar five years from now + + + align:start position:0% +year and a dollar five years from now +they aren't the same thing + + align:start position:0% +they aren't the same thing + + + align:start position:0% +they aren't the same thing +money received at different points of + + align:start position:0% +money received at different points of + + + align:start position:0% +money received at different points of +time or worth different amounts because + + align:start position:0% +time or worth different amounts because + + + align:start position:0% +time or worth different amounts because +money received in the future forgoes the + + align:start position:0% +money received in the future forgoes the + + + align:start position:0% +money received in the future forgoes the +possibility of investing it today okay + + align:start position:0% +possibility of investing it today okay + + + align:start position:0% +possibility of investing it today okay +so what do we do to deal with this well + + align:start position:0% +so what do we do to deal with this well + + + align:start position:0% +so what do we do to deal with this well +in economics we deal with this bike the + + align:start position:0% +in economics we deal with this bike the + + + align:start position:0% +in economics we deal with this bike the +concept of present value present value + + align:start position:0% +concept of present value present value + + + align:start position:0% +concept of present value present value +is the value of every periods payment + + align:start position:0% +is the value of every periods payment + + + align:start position:0% +is the value of every periods payment +in terms of today so the way we deal + + align:start position:0% +in terms of today so the way we deal + + + align:start position:0% +in terms of today so the way we deal +with the fact that money different + + align:start position:0% +with the fact that money different + + + align:start position:0% +with the fact that money different +parents worth different amounts is by + + align:start position:0% +parents worth different amounts is by + + + align:start position:0% +parents worth different amounts is by +what we call discounting it back to + + align:start position:0% +what we call discounting it back to + + + align:start position:0% +what we call discounting it back to +today we said so take future dollars and + + align:start position:0% +today we said so take future dollars and + + + align:start position:0% +today we said so take future dollars and +dip it discount them back to today to + + align:start position:0% +dip it discount them back to today to + + + align:start position:0% +dip it discount them back to today to +get present value we discount them + + align:start position:0% +get present value we discount them + + + align:start position:0% +get present value we discount them +because future dollars are worthless + + align:start position:0% +because future dollars are worthless + + + align:start position:0% +because future dollars are worthless +okay so let's think of it this way + + align:start position:0% +okay so let's think of it this way + + + align:start position:0% +okay so let's think of it this way +suppose that um the interest rate is 10 + + align:start position:0% +suppose that um the interest rate is 10 + + + align:start position:0% +suppose that um the interest rate is 10 +percent let students they have imagine + + align:start position:0% +percent let students they have imagine + + + align:start position:0% +percent let students they have imagine +the interest rate I is 10 percent and + + align:start position:0% +the interest rate I is 10 percent and + + + align:start position:0% +the interest rate I is 10 percent and +let's say that you want to have 100 + + align:start position:0% +let's say that you want to have 100 + + + align:start position:0% +let's say that you want to have 100 +dollars next year you want your you want + + align:start position:0% +dollars next year you want your you want + + + align:start position:0% +dollars next year you want your you want +next year you want to have 100 dollars + + align:start position:0% +next year you want to have 100 dollars + + + align:start position:0% +next year you want to have 100 dollars +well how much do you have to put in the + + align:start position:0% +well how much do you have to put in the + + + align:start position:0% +well how much do you have to put in the +bank today okay well we could solve the + + align:start position:0% +bank today okay well we could solve the + + + align:start position:0% +bank today okay well we could solve the +equation which is that you want the + + align:start position:0% +equation which is that you want the + + + align:start position:0% +equation which is that you want the +amount you put in the bank today let's + + align:start position:0% +amount you put in the bank today let's + + + align:start position:0% +amount you put in the bank today let's +call that Y times 1 plus the interest + + align:start position:0% +call that Y times 1 plus the interest + + + align:start position:0% +call that Y times 1 plus the interest +rate because that's what you make by + + align:start position:0% +rate because that's what you make by + + + align:start position:0% +rate because that's what you make by +having the bank equal to 100 that's + + align:start position:0% +having the bank equal to 100 that's + + + align:start position:0% +having the bank equal to 100 that's +equation we want to solve right the + + align:start position:0% +equation we want to solve right the + + + align:start position:0% +equation we want to solve right the +money you've bout you put in today y + + align:start position:0% +money you've bout you put in today y + + + align:start position:0% +money you've bout you put in today y +times 1 plus the interest rate you want + + align:start position:0% +times 1 plus the interest rate you want + + + align:start position:0% +times 1 plus the interest rate you want +that to be equal to 100 so what that + + align:start position:0% +that to be equal to 100 so what that + + + align:start position:0% +that to be equal to 100 so what that +says is that y equals 90 point nine if + + align:start position:0% +says is that y equals 90 point nine if + + + align:start position:0% +says is that y equals 90 point nine if +you put $90.90 + + align:start position:0% +you put $90.90 + + + align:start position:0% +you put $90.90 +in the bank today at a 10 percent + + align:start position:0% +in the bank today at a 10 percent + + + align:start position:0% +in the bank today at a 10 percent +interest rate you will have $100 + + align:start position:0% +interest rate you will have $100 + + + align:start position:0% +interest rate you will have $100 +tomorrow more generally we say that the + + align:start position:0% +tomorrow more generally we say that the + + + align:start position:0% +tomorrow more generally we say that the +present value of any future payment it's + + align:start position:0% +present value of any future payment it's + + + align:start position:0% +present value of any future payment it's +the future value the amount you get in + + align:start position:0% +the future value the amount you get in + + + align:start position:0% +the future value the amount you get in +the future over 1 plus I to the power + + align:start position:0% +the future over 1 plus I to the power + + + align:start position:0% +the future over 1 plus I to the power +little T where T is the periods in the + + align:start position:0% +little T where T is the periods in the + + + align:start position:0% +little T where T is the periods in the +future so money received t periods in + + align:start position:0% +future so money received t periods in + + + align:start position:0% +future so money received t periods in +the future today is worth the amount you + + align:start position:0% +the future today is worth the amount you + + + align:start position:0% +the future today is worth the amount you +get in the future over 1 plus I to the T + + align:start position:0% +get in the future over 1 plus I to the T + + + align:start position:0% +get in the future over 1 plus I to the T +okay so that is our general formula for + + align:start position:0% +okay so that is our general formula for + + + align:start position:0% +okay so that is our general formula for +how we think about present value take + + align:start position:0% +how we think about present value take + + + align:start position:0% +how we think about present value take +all the future payments and you discount + + align:start position:0% +all the future payments and you discount + + + align:start position:0% +all the future payments and you discount +them back today by dividing by 1 call + + align:start position:0% +them back today by dividing by 1 call + + + align:start position:0% +them back today by dividing by 1 call +side of the T now that works well if + + align:start position:0% +side of the T now that works well if + + + align:start position:0% +side of the T now that works well if +there's a future payment in one future + + align:start position:0% +there's a future payment in one future + + + align:start position:0% +there's a future payment in one future +payment coming but what if as in many + + align:start position:0% +payment coming but what if as in many + + + align:start position:0% +payment coming but what if as in many +cases is the whole stream of future + + align:start position:0% +cases is the whole stream of future + + + align:start position:0% +cases is the whole stream of future +payments coming well the logic then is + + align:start position:0% +payments coming well the logic then is + + + align:start position:0% +payments coming well the logic then is +the same you just want to take each + + align:start position:0% +the same you just want to take each + + + align:start position:0% +the same you just want to take each +future payment and discount it by how + + align:start position:0% +future payment and discount it by how + + + align:start position:0% +future payment and discount it by how +far it is in the future + + align:start position:0% +far it is in the future + + + align:start position:0% +far it is in the future +okay so suppose that you say um that you + + align:start position:0% +okay so suppose that you say um that you + + + align:start position:0% +okay so suppose that you say um that you +want me to loan you $30 and that you'll + + align:start position:0% +want me to loan you $30 and that you'll + + + align:start position:0% +want me to loan you $30 and that you'll +pay me back $10 each of the next three + + align:start position:0% +pay me back $10 each of the next three + + + align:start position:0% +pay me back $10 each of the next three +years okay + + align:start position:0% +years okay + + + align:start position:0% +years okay +and suppose the interest rates 10% well + + align:start position:0% +and suppose the interest rates 10% well + + + align:start position:0% +and suppose the interest rates 10% well +I will say no to that because I will say + + align:start position:0% +I will say no to that because I will say + + + align:start position:0% +I will say no to that because I will say +if you're gonna pay me back $10 each of + + align:start position:0% +if you're gonna pay me back $10 each of + + + align:start position:0% +if you're gonna pay me back $10 each of +the next three years then what is it + + align:start position:0% +the next three years then what is it + + + align:start position:0% +the next three years then what is it +what's the present value of that the + + align:start position:0% +what's the present value of that the + + + align:start position:0% +what's the present value of that the +present value is next year's $10 over + + align:start position:0% +present value is next year's $10 over + + + align:start position:0% +present value is next year's $10 over +1.1 because the interest rate is 10% + + align:start position:0% +1.1 because the interest rate is 10% + + + align:start position:0% +1.1 because the interest rate is 10% +plus the $10 a year after that over 1.1 + + align:start position:0% +plus the $10 a year after that over 1.1 + + + align:start position:0% +plus the $10 a year after that over 1.1 +squared plus the $10 the year after that + + align:start position:0% +squared plus the $10 the year after that + + + align:start position:0% +squared plus the $10 the year after that +over 1.1 cubed which way if I add it up + + align:start position:0% +over 1.1 cubed which way if I add it up + + + align:start position:0% +over 1.1 cubed which way if I add it up +is 24 87 so I am losing money if I if I + + align:start position:0% +is 24 87 so I am losing money if I if I + + + align:start position:0% +is 24 87 so I am losing money if I if I +give you $30 today and if you give me + + align:start position:0% +give you $30 today and if you give me + + + align:start position:0% +give you $30 today and if you give me +$10 back each of the next three years + + align:start position:0% +$10 back each of the next three years + + + align:start position:0% +$10 back each of the next three years +I'm losing money why because if I had + + align:start position:0% +I'm losing money why because if I had + + + align:start position:0% +I'm losing money why because if I had +simply taken that money and invested in + + align:start position:0% +simply taken that money and invested in + + + align:start position:0% +simply taken that money and invested in +the bank I would have had a lot more + + align:start position:0% +the bank I would have had a lot more + + + align:start position:0% +the bank I would have had a lot more +than the $30 I'm gonna get for you after + + align:start position:0% +than the $30 I'm gonna get for you after + + + align:start position:0% +than the $30 I'm gonna get for you after +three years okay so the money that comes + + align:start position:0% +three years okay so the money that comes + + + align:start position:0% +three years okay so the money that comes +in the future must be discounted back to + + align:start position:0% +in the future must be discounted back to + + + align:start position:0% +in the future must be discounted back to +today that's the key inside of present + + align:start position:0% +today that's the key inside of present + + + align:start position:0% +today that's the key inside of present +value you can't just add it up you've + + align:start position:0% +value you can't just add it up you've + + + align:start position:0% +value you can't just add it up you've +got to put it in today's terms by + + align:start position:0% +got to put it in today's terms by + + + align:start position:0% +got to put it in today's terms by +discounting it by the interest rate and + + align:start position:0% +discounting it by the interest rate and + + + align:start position:0% +discounting it by the interest rate and +how far it for future yeah + + align:start position:0% + + + + align:start position:0% + +we're assuming now inflation zero so + + align:start position:0% +we're assuming now inflation zero so + + + align:start position:0% +we're assuming now inflation zero so +we're assuming right now we're not doing + + align:start position:0% +we're assuming right now we're not doing + + + align:start position:0% +we're assuming right now we're not doing +with inflation we're assuming a world + + align:start position:0% +with inflation we're assuming a world + + + align:start position:0% +with inflation we're assuming a world +where prices don't change we'll come + + align:start position:0% +where prices don't change we'll come + + + align:start position:0% +where prices don't change we'll come +back to inflation in a few minutes but + + align:start position:0% +back to inflation in a few minutes but + + + align:start position:0% +back to inflation in a few minutes but +for now just assume that prices don't + + align:start position:0% +for now just assume that prices don't + + + align:start position:0% +for now just assume that prices don't +change okay so basically arm essentially + + align:start position:0% +change okay so basically arm essentially + + + align:start position:0% +change okay so basically arm essentially +the formula then for the present value + + align:start position:0% +the formula then for the present value + + + align:start position:0% +the formula then for the present value +your general formula for present value + + align:start position:0% +your general formula for present value + + + align:start position:0% +your general formula for present value +you need to know is the present value + + align:start position:0% +you need to know is the present value + + + align:start position:0% +you need to know is the present value +equals present value equals if you get a + + align:start position:0% +equals present value equals if you get a + + + align:start position:0% +equals present value equals if you get a +flat stream of payment F for a number of + + align:start position:0% +flat stream of payment F for a number of + + + align:start position:0% +flat stream of payment F for a number of +periods it's f times 1 over 1 plus I to + + align:start position:0% +periods it's f times 1 over 1 plus I to + + + align:start position:0% +periods it's f times 1 over 1 plus I to +the T plus 1 I'm sorry 1 over 1 plus I + + align:start position:0% +the T plus 1 I'm sorry 1 over 1 plus I + + + align:start position:0% +the T plus 1 I'm sorry 1 over 1 plus I +to the 1 plus 1 over 1 plus I squared + + align:start position:0% +to the 1 plus 1 over 1 plus I squared + + + align:start position:0% +to the 1 plus 1 over 1 plus I squared +plus 1 over 1 plus I cubed plus not that + + align:start position:0% +plus 1 over 1 plus I cubed plus not that + + + align:start position:0% +plus 1 over 1 plus I cubed plus not that +up at the top for how many periods you + + align:start position:0% +up at the top for how many periods you + + + align:start position:0% +up at the top for how many periods you +get it so if you're getting a payment F + + align:start position:0% +get it so if you're getting a payment F + + + align:start position:0% +get it so if you're getting a payment F +over a certain number of periods + + align:start position:0% +over a certain number of periods + + + align:start position:0% +over a certain number of periods +you've got to discount it by how many + + align:start position:0% +you've got to discount it by how many + + + align:start position:0% +you've got to discount it by how many +periods you're gonna get it okay + + align:start position:0% +periods you're gonna get it okay + + + align:start position:0% +periods you're gonna get it okay +or more generally a common formula will + + align:start position:0% +or more generally a common formula will + + + align:start position:0% +or more generally a common formula will +ask you to use in this class is to think + + align:start position:0% +ask you to use in this class is to think + + + align:start position:0% +ask you to use in this class is to think +about the formula for a perpetuity a + + align:start position:0% +about the formula for a perpetuity a + + + align:start position:0% +about the formula for a perpetuity a +perpetuity is a flat payment you get + + align:start position:0% +perpetuity is a flat payment you get + + + align:start position:0% +perpetuity is a flat payment you get +forever so if we think the infinite sum + + align:start position:0% +forever so if we think the infinite sum + + + align:start position:0% +forever so if we think the infinite sum +of this equation we can summarize it as + + align:start position:0% +of this equation we can summarize it as + + + align:start position:0% +of this equation we can summarize it as +present value approximately equals F + + align:start position:0% +present value approximately equals F + + + align:start position:0% +present value approximately equals F +over the interest rate so if I promise + + align:start position:0% +over the interest rate so if I promise + + + align:start position:0% +over the interest rate so if I promise +you to pay you forever a certain amount + + align:start position:0% +you to pay you forever a certain amount + + + align:start position:0% +you to pay you forever a certain amount +F that is worth F over the interest rate + + align:start position:0% +F that is worth F over the interest rate + + + align:start position:0% +F that is worth F over the interest rate +so in other words if each rates 10% a + + align:start position:0% +so in other words if each rates 10% a + + + align:start position:0% +so in other words if each rates 10% a +promise to pay you $10 forever is worth + + align:start position:0% +promise to pay you $10 forever is worth + + + align:start position:0% +promise to pay you $10 forever is worth +about a hundred bucks that's the rough + + align:start position:0% +about a hundred bucks that's the rough + + + align:start position:0% +about a hundred bucks that's the rough +that's just the infinite sum if you read + + align:start position:0% +that's just the infinite sum if you read + + + align:start position:0% +that's just the infinite sum if you read +a beautiful mind John Nash through that + + align:start position:0% +a beautiful mind John Nash through that + + + align:start position:0% +a beautiful mind John Nash through that +in his head but I can't but that's just + + align:start position:0% +in his head but I can't but that's just + + + align:start position:0% +in his head but I can't but that's just +the formula okay so basically that is + + align:start position:0% +the formula okay so basically that is + + + align:start position:0% +the formula okay so basically that is +the general formula for perpetuity and + + align:start position:0% +the general formula for perpetuity and + + + align:start position:0% +the general formula for perpetuity and +that makes and that makes a life easy + + align:start position:0% +that makes and that makes a life easy + + + align:start position:0% +that makes and that makes a life easy +will give you a lot of examples where we + + align:start position:0% +will give you a lot of examples where we + + + align:start position:0% +will give you a lot of examples where we +you know cuz if I say I want you to pay + + align:start position:0% +you know cuz if I say I want you to pay + + + align:start position:0% +you know cuz if I say I want you to pay +them for eight years in the future you + + align:start position:0% +them for eight years in the future you + + + align:start position:0% +them for eight years in the future you +got to write out eight terms here it's a + + align:start position:0% +got to write out eight terms here it's a + + + align:start position:0% +got to write out eight terms here it's a +pain in the ass so it will say is money + + align:start position:0% +pain in the ass so it will say is money + + + align:start position:0% +pain in the ass so it will say is money +forever and they can just use this + + align:start position:0% +forever and they can just use this + + + align:start position:0% +forever and they can just use this +shortcut which is the present value for + + align:start position:0% +shortcut which is the present value for + + + align:start position:0% +shortcut which is the present value for +a perpetuity it's just F over I okay + + align:start position:0% +a perpetuity it's just F over I okay + + + align:start position:0% +a perpetuity it's just F over I okay +questions about that yeah that's a great + + align:start position:0% +questions about that yeah that's a great + + + align:start position:0% +questions about that yeah that's a great +point + + align:start position:0% +point + + + align:start position:0% +point +yes I'm assuming constant just rate over + + align:start position:0% +yes I'm assuming constant just rate over + + + align:start position:0% +yes I'm assuming constant just rate over +time now in reality you'd want to have + + align:start position:0% +time now in reality you'd want to have + + + align:start position:0% +time now in reality you'd want to have +each periods interest rate here and then + + align:start position:0% +each periods interest rate here and then + + + align:start position:0% +each periods interest rate here and then +you can't use this formula because the + + align:start position:0% +you can't use this formula because the + + + align:start position:0% +you can't use this formula because the +interest rate itself is changing very + + align:start position:0% +interest rate itself is changing very + + + align:start position:0% +interest rate itself is changing very +good point okay now the other way to + + align:start position:0% +good point okay now the other way to + + + align:start position:0% +good point okay now the other way to +think about this is instead of thinking + + align:start position:0% +think about this is instead of thinking + + + align:start position:0% +think about this is instead of thinking +just this this will be easy for most of + + align:start position:0% +just this this will be easy for most of + + + align:start position:0% +just this this will be easy for most of +you but just it's useful to think it + + align:start position:0% +you but just it's useful to think it + + + align:start position:0% +you but just it's useful to think it +through let's flip on his head not think + + align:start position:0% +through let's flip on his head not think + + + align:start position:0% +through let's flip on his head not think +about present valueless think about + + align:start position:0% +about present valueless think about + + + align:start position:0% +about present valueless think about +future value this is a useful tool as + + align:start position:0% +future value this is a useful tool as + + + align:start position:0% +future value this is a useful tool as +well as slipping on its head okay + + align:start position:0% +well as slipping on its head okay + + + align:start position:0% +well as slipping on its head okay +so let's think about the value of a + + align:start position:0% +so let's think about the value of a + + + align:start position:0% +so let's think about the value of a +future stream of payments well by the + + align:start position:0% +future stream of payments well by the + + + align:start position:0% +future stream of payments well by the +same logic we wrote before future value + + align:start position:0% +same logic we wrote before future value + + + align:start position:0% +same logic we wrote before future value +by same watch we wrote before if you're + + align:start position:0% +by same watch we wrote before if you're + + + align:start position:0% +by same watch we wrote before if you're +gonna have money that's tears in the + + align:start position:0% +gonna have money that's tears in the + + + align:start position:0% +gonna have money that's tears in the +future the future value of that money + + align:start position:0% +future the future value of that money + + + align:start position:0% +future the future value of that money +that you're gonna get okay if you're + + align:start position:0% +that you're gonna get okay if you're + + + align:start position:0% +that you're gonna get okay if you're +gonna basically take your money and + + align:start position:0% +gonna basically take your money and + + + align:start position:0% +gonna basically take your money and +invest it you're gonna have money that + + align:start position:0% +invest it you're gonna have money that + + + align:start position:0% +invest it you're gonna have money that +you're gonna invest today and put it in + + align:start position:0% +you're gonna invest today and put it in + + + align:start position:0% +you're gonna invest today and put it in +the bank and some interest rate then the + + align:start position:0% +the bank and some interest rate then the + + + align:start position:0% +the bank and some interest rate then the +future value is the amount you put in + + align:start position:0% +future value is the amount you put in + + + align:start position:0% +future value is the amount you put in +times one plus the interest rate tunity + + align:start position:0% +times one plus the interest rate tunity + + + align:start position:0% +times one plus the interest rate tunity +so I've simply reversed that formula + + align:start position:0% +so I've simply reversed that formula + + + align:start position:0% +so I've simply reversed that formula +present value future value + + align:start position:0% +present value future value + + + align:start position:0% +present value future value +so basically future value if you put + + align:start position:0% +so basically future value if you put + + + align:start position:0% +so basically future value if you put +money in the bank at some interest rate + + align:start position:0% +money in the bank at some interest rate + + + align:start position:0% +money in the bank at some interest rate +you're going to get to have over time + + align:start position:0% +you're going to get to have over time + + + align:start position:0% +you're going to get to have over time +that money times 1 plus I to the T now + + align:start position:0% +that money times 1 plus I to the T now + + + align:start position:0% +that money times 1 plus I to the T now +the reason we write this formula and + + align:start position:0% +the reason we write this formula and + + + align:start position:0% +the reason we write this formula and +sort of flip it for you is because I + + align:start position:0% +sort of flip it for you is because I + + + align:start position:0% +sort of flip it for you is because I +want to highlight the key feature here + + align:start position:0% +want to highlight the key feature here + + + align:start position:0% +want to highlight the key feature here +then I want to drill into your heads one + + align:start position:0% +then I want to drill into your heads one + + + align:start position:0% +then I want to drill into your heads one +of them I don't know I guess 10 things I + + align:start position:0% +of them I don't know I guess 10 things I + + + align:start position:0% +of them I don't know I guess 10 things I +most care you leave this course thinking + + align:start position:0% +most care you leave this course thinking + + + align:start position:0% +most care you leave this course thinking +about if you're not gonna major in + + align:start position:0% +about if you're not gonna major in + + + align:start position:0% +about if you're not gonna major in +economics but remembering is the beauty + + align:start position:0% +economics but remembering is the beauty + + + align:start position:0% +economics but remembering is the beauty +of compounding which is that with a + + align:start position:0% +of compounding which is that with a + + + align:start position:0% +of compounding which is that with a +formula like this you weren't interest + + align:start position:0% +formula like this you weren't interest + + + align:start position:0% +formula like this you weren't interest +on your interest if you leave money in + + align:start position:0% +on your interest if you leave money in + + + align:start position:0% +on your interest if you leave money in +the bank you don't just earn interest on + + align:start position:0% +the bank you don't just earn interest on + + + align:start position:0% +the bank you don't just earn interest on +the initial amount you put in your an + + align:start position:0% +the initial amount you put in your an + + + align:start position:0% +the initial amount you put in your an +interest on the interest you earn over + + align:start position:0% +interest on the interest you earn over + + + align:start position:0% +interest on the interest you earn over +time ok and this can be quite large so + + align:start position:0% +time ok and this can be quite large so + + + align:start position:0% +time ok and this can be quite large so +let's do a simple example ok just to + + align:start position:0% +let's do a simple example ok just to + + + align:start position:0% +let's do a simple example ok just to +show you how big this can be to get you + + align:start position:0% +show you how big this can be to get you + + + align:start position:0% +show you how big this can be to get you +all thinking about what you should do + + align:start position:0% +all thinking about what you should do + + + align:start position:0% +all thinking about what you should do +with your money when you get a job ok + + align:start position:0% +with your money when you get a job ok + + + align:start position:0% +with your money when you get a job ok +imagine you plan to work full time from + + align:start position:0% +imagine you plan to work full time from + + + align:start position:0% +imagine you plan to work full time from +age 22 to age 70 + + align:start position:0% +age 22 to age 70 + + + align:start position:0% +age 22 to age 70 +well daunting to think about now + + align:start position:0% +well daunting to think about now + + + align:start position:0% +well daunting to think about now +probably + + align:start position:0% +probably + + + align:start position:0% +probably +to retire after 70 by the time you guys + + align:start position:0% +to retire after 70 by the time you guys + + + align:start position:0% +to retire after 70 by the time you guys +retire but let's just think about 22 to + + align:start position:0% +retire but let's just think about 22 to + + + align:start position:0% +retire but let's just think about 22 to +70 okay and let's say that you can save + + align:start position:0% +70 okay and let's say that you can save + + + align:start position:0% +70 okay and let's say that you can save +at a constant 7% interest rate inflation + + align:start position:0% +at a constant 7% interest rate inflation + + + align:start position:0% +at a constant 7% interest rate inflation +zero the interest rates constant make + + align:start position:0% +zero the interest rates constant make + + + align:start position:0% +zero the interest rates constant make +life easy 7% interest rate okay and + + align:start position:0% +life easy 7% interest rate okay and + + + align:start position:0% +life easy 7% interest rate okay and +let's consider two different plans you + + align:start position:0% +let's consider two different plans you + + + align:start position:0% +let's consider two different plans you +have for savings plan one plan one is + + align:start position:0% +have for savings plan one plan one is + + + align:start position:0% +have for savings plan one plan one is +that you're gonna save $3,000 a year for + + align:start position:0% +that you're gonna save $3,000 a year for + + + align:start position:0% +that you're gonna save $3,000 a year for +the first 15 years that you work and + + align:start position:0% +the first 15 years that you work and + + + align:start position:0% +the first 15 years that you work and +then stop saving 3000 0:15 is then you + + align:start position:0% +then stop saving 3000 0:15 is then you + + + align:start position:0% +then stop saving 3000 0:15 is then you +just gonna leave that in the bank leave + + align:start position:0% +just gonna leave that in the bank leave + + + align:start position:0% +just gonna leave that in the bank leave +alone never save any more just let that + + align:start position:0% +alone never save any more just let that + + + align:start position:0% +alone never save any more just let that +money sit in the bank okay well in that + + align:start position:0% +money sit in the bank okay well in that + + + align:start position:0% +money sit in the bank okay well in that +case what will you have + + align:start position:0% +case what will you have + + + align:start position:0% +case what will you have +well after the first 15 years of putting + + align:start position:0% +well after the first 15 years of putting + + + align:start position:0% +well after the first 15 years of putting +three thousand dollars in the bank every + + align:start position:0% +three thousand dollars in the bank every + + + align:start position:0% +three thousand dollars in the bank every +year if you work out the math you will + + align:start position:0% +year if you work out the math you will + + + align:start position:0% +year if you work out the math you will +have $75,000 75387 + + align:start position:0% +have $75,000 75387 + + + align:start position:0% +have $75,000 75387 +after 15 years okay that's now that's + + align:start position:0% +after 15 years okay that's now that's + + + align:start position:0% +after 15 years okay that's now that's +not just fifteen years times that's + + align:start position:0% +not just fifteen years times that's + + + align:start position:0% +not just fifteen years times that's +bigger than fifteen times 3,000 cuz + + align:start position:0% +bigger than fifteen times 3,000 cuz + + + align:start position:0% +bigger than fifteen times 3,000 cuz +you're earning interest along the way + + align:start position:0% +you're earning interest along the way + + + align:start position:0% +you're earning interest along the way +okay that's nice fifteen years then + + align:start position:0% +okay that's nice fifteen years then + + + align:start position:0% +okay that's nice fifteen years then +you're just gonna let that sit there and + + align:start position:0% +you're just gonna let that sit there and + + + align:start position:0% +you're just gonna let that sit there and +that's gonna sit there + + align:start position:0% +that's gonna sit there + + + align:start position:0% +that's gonna sit there +remember after 15 years you started + + align:start position:0% +remember after 15 years you started + + + align:start position:0% +remember after 15 years you started +working at 22 only 37 years old that's + + align:start position:0% +working at 22 only 37 years old that's + + + align:start position:0% +working at 22 only 37 years old that's +gonna then sit there for the next 33 + + align:start position:0% +gonna then sit there for the next 33 + + + align:start position:0% +gonna then sit there for the next 33 +years you're not gonna touch it I could + + align:start position:0% +years you're not gonna touch it I could + + + align:start position:0% +years you're not gonna touch it I could +save anymore + + align:start position:0% +save anymore + + + align:start position:0% +save anymore +what that means is after 33 years this + + align:start position:0% +what that means is after 33 years this + + + align:start position:0% +what that means is after 33 years this +turns into 75 387 times 1.07 to the 33rd + + align:start position:0% +turns into 75 387 times 1.07 to the 33rd + + + align:start position:0% +turns into 75 387 times 1.07 to the 33rd +okay after 33 years or seven hundred and + + align:start position:0% +okay after 33 years or seven hundred and + + + align:start position:0% +okay after 33 years or seven hundred and +three thousand dollars seven oh three oh + + align:start position:0% +three thousand dollars seven oh three oh + + + align:start position:0% +three thousand dollars seven oh three oh +ten okay so you save $3,000 it's not a + + align:start position:0% +ten okay so you save $3,000 it's not a + + + align:start position:0% +ten okay so you save $3,000 it's not a +lot of money you guys gonna make a lot + + align:start position:0% +lot of money you guys gonna make a lot + + + align:start position:0% +lot of money you guys gonna make a lot +of money three thousand dollars for 15 + + align:start position:0% +of money three thousand dollars for 15 + + + align:start position:0% +of money three thousand dollars for 15 +years and then you never had to save + + align:start position:0% +years and then you never had to save + + + align:start position:0% +years and then you never had to save +again contrast that with different + + align:start position:0% +again contrast that with different + + + align:start position:0% +again contrast that with different +approach let's say you say look that's + + align:start position:0% +approach let's say you say look that's + + + align:start position:0% +approach let's say you say look that's +stupid I'm young I'm gonna party I'll + + align:start position:0% +stupid I'm young I'm gonna party I'll + + + align:start position:0% +stupid I'm young I'm gonna party I'll +worry about retirement retirements close + + align:start position:0% +worry about retirement retirements close + + + align:start position:0% +worry about retirement retirements close +so I'm gonna save nothing the first 15 + + align:start position:0% +so I'm gonna save nothing the first 15 + + + align:start position:0% +so I'm gonna save nothing the first 15 +years and then I'm gonna save three + + align:start position:0% +years and then I'm gonna save three + + + align:start position:0% +years and then I'm gonna save three +thousand dollars every year for 15 years + + align:start position:0% +thousand dollars every year for 15 years + + + align:start position:0% +thousand dollars every year for 15 years +I'm going to save nothing then I'll save + + align:start position:0% +I'm going to save nothing then I'll save + + + align:start position:0% +I'm going to save nothing then I'll save +$3,000 over year okay well if you do + + align:start position:0% +$3,000 over year okay well if you do + + + align:start position:0% +$3,000 over year okay well if you do +that and do the math you end up with + + align:start position:0% +that and do the math you end up with + + + align:start position:0% +that and do the math you end up with +when you retire three fifty six eight + + align:start position:0% +when you retire three fifty six eight + + + align:start position:0% +when you retire three fifty six eight +hundred + + align:start position:0% + + + + align:start position:0% + +think about this for one second + + align:start position:0% +think about this for one second + + + align:start position:0% +think about this for one second +in this case you save for two more than + + align:start position:0% +in this case you save for two more than + + + align:start position:0% +in this case you save for two more than +twice as many years you say for 33 years + + align:start position:0% +twice as many years you say for 33 years + + + align:start position:0% +twice as many years you say for 33 years +and you ended up with half as much + + align:start position:0% +and you ended up with half as much + + + align:start position:0% +and you ended up with half as much +that's the miracle of compounding the + + align:start position:0% +that's the miracle of compounding the + + + align:start position:0% +that's the miracle of compounding the +earlier you save the more money you can + + align:start position:0% +earlier you save the more money you can + + + align:start position:0% +earlier you save the more money you can +make it along the way and that's why you + + align:start position:0% +make it along the way and that's why you + + + align:start position:0% +make it along the way and that's why you +guys need to start saving right away + + align:start position:0% +guys need to start saving right away + + + align:start position:0% +guys need to start saving right away +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +plan 2 was I do nothing the first 15 + + align:start position:0% +plan 2 was I do nothing the first 15 + + + align:start position:0% +plan 2 was I do nothing the first 15 +years then I save the remaining 30 I + + align:start position:0% +years then I save the remaining 30 I + + + align:start position:0% +years then I save the remaining 30 I +save $3,000 in for the mating 30 years + + align:start position:0% +save $3,000 in for the mating 30 years + + + align:start position:0% +save $3,000 in for the mating 30 years +of my career okay so literally in + + align:start position:0% +of my career okay so literally in + + + align:start position:0% +of my career okay so literally in +playing one I say for 15 years and then + + align:start position:0% +playing one I say for 15 years and then + + + align:start position:0% +playing one I say for 15 years and then +I stop here I say for 33 years but by + + align:start position:0% +I stop here I say for 33 years but by + + + align:start position:0% +I stop here I say for 33 years but by +starting early and using the miracle of + + align:start position:0% +starting early and using the miracle of + + + align:start position:0% +starting early and using the miracle of +compounding ended put twice as much + + align:start position:0% +compounding ended put twice as much + + + align:start position:0% +compounding ended put twice as much +money okay now this is actually pretty I + + align:start position:0% +money okay now this is actually pretty I + + + align:start position:0% +money okay now this is actually pretty I +can act this is one of the few things in + + align:start position:0% +can act this is one of the few things in + + + align:start position:0% +can act this is one of the few things in +this class my kids can understand when + + align:start position:0% +this class my kids can understand when + + + align:start position:0% +this class my kids can understand when +they were little + + align:start position:0% +they were little + + + align:start position:0% +they were little +because having hadn't been to Boston + + align:start position:0% +because having hadn't been to Boston + + + align:start position:0% +because having hadn't been to Boston +Science Museum and you guys been okay if + + align:start position:0% +Science Museum and you guys been okay if + + + align:start position:0% +Science Museum and you guys been okay if +there's a little kid area where they've + + align:start position:0% +there's a little kid area where they've + + + align:start position:0% +there's a little kid area where they've +got this ramp and you can essentially + + align:start position:0% +got this ramp and you can essentially + + + align:start position:0% +got this ramp and you can essentially +drop balls down a ramp and one ramp is + + align:start position:0% +drop balls down a ramp and one ramp is + + + align:start position:0% +drop balls down a ramp and one ramp is +flat and then steep and one ramp is + + align:start position:0% +flat and then steep and one ramp is + + + align:start position:0% +flat and then steep and one ramp is +steep and then flat and of course the + + align:start position:0% +steep and then flat and of course the + + + align:start position:0% +steep and then flat and of course the +one that's steeper than flat wins it's + + align:start position:0% +one that's steeper than flat wins it's + + + align:start position:0% +one that's steeper than flat wins it's +faster and that's just because of + + align:start position:0% +faster and that's just because of + + + align:start position:0% +faster and that's just because of +compounding that's because acceleration + + align:start position:0% +compounding that's because acceleration + + + align:start position:0% +compounding that's because acceleration +is compounding okay so basically the + + align:start position:0% +is compounding okay so basically the + + + align:start position:0% +is compounding okay so basically the +point is that the earlier you start + + align:start position:0% +point is that the earlier you start + + + align:start position:0% +point is that the earlier you start +saving the more money you'll have and + + align:start position:0% +saving the more money you'll have and + + + align:start position:0% +saving the more money you'll have and +that's why you guys should pay attention + + align:start position:0% +that's why you guys should pay attention + + + align:start position:0% +that's why you guys should pay attention +when you're offered a job and offer 401 + + align:start position:0% +when you're offered a job and offer 401 + + + align:start position:0% +when you're offered a job and offer 401 +K and I think retirement I'll never + + align:start position:0% +K and I think retirement I'll never + + + align:start position:0% +K and I think retirement I'll never +retire you say no I want to save now + + align:start position:0% +retire you say no I want to save now + + + align:start position:0% +retire you say no I want to save now +because the more I saved now the more + + align:start position:0% +because the more I saved now the more + + + align:start position:0% +because the more I saved now the more +that'll compound by the time I retire + + align:start position:0% +that'll compound by the time I retire + + + align:start position:0% +that'll compound by the time I retire +okay now you can actually see this it's + + align:start position:0% +okay now you can actually see this it's + + + align:start position:0% +okay now you can actually see this it's +not just MIT students have to think + + align:start position:0% +not just MIT students have to think + + + align:start position:0% +not just MIT students have to think +about this but professional athletes so + + align:start position:0% +about this but professional athletes so + + + align:start position:0% +about this but professional athletes so +probably none of you have heard of Bobby + + align:start position:0% +probably none of you have heard of Bobby + + + align:start position:0% +probably none of you have heard of Bobby +Bonilla any of you guys heard of Bobby + + align:start position:0% +Bonilla any of you guys heard of Bobby + + + align:start position:0% +Bonilla any of you guys heard of Bobby +Benina no okay well if you were 25 years + + align:start position:0% +Benina no okay well if you were 25 years + + + align:start position:0% +Benina no okay well if you were 25 years +ago in this class if you were to support + + align:start position:0% +ago in this class if you were to support + + + align:start position:0% +ago in this class if you were to support +you order in Bobby benita he was a + + align:start position:0% +you order in Bobby benita he was a + + + align:start position:0% +you order in Bobby benita he was a +pretty good player in his time and um he + + align:start position:0% +pretty good player in his time and um he + + + align:start position:0% +pretty good player in his time and um he +retired + + align:start position:0% +retired + + + align:start position:0% +retired +um he but by the end of his career he + + align:start position:0% +um he but by the end of his career he + + + align:start position:0% +um he but by the end of his career he +was kind of a slacker he wasn't really + + align:start position:0% +was kind of a slacker he wasn't really + + + align:start position:0% +was kind of a slacker he wasn't really +worth much he was playing for the Mets + + align:start position:0% +worth much he was playing for the Mets + + + align:start position:0% +worth much he was playing for the Mets +and the Mets said look in 1999 they said + + align:start position:0% +and the Mets said look in 1999 they said + + + align:start position:0% +and the Mets said look in 1999 they said +look we basically want to pay you off to + + align:start position:0% +look we basically want to pay you off to + + + align:start position:0% +look we basically want to pay you off to +leave the team + + align:start position:0% +leave the team + + + align:start position:0% +leave the team +you have a contract we're just gonna + + align:start position:0% +you have a contract we're just gonna + + + align:start position:0% +you have a contract we're just gonna +sleep I pay the remaining 5.9 million on + + align:start position:0% +sleep I pay the remaining 5.9 million on + + + align:start position:0% +sleep I pay the remaining 5.9 million on +your contract in 1999 give me the money + + align:start position:0% +your contract in 1999 give me the money + + + align:start position:0% +your contract in 1999 give me the money +most athletes would have said great I'm + + align:start position:0% +most athletes would have said great I'm + + + align:start position:0% +most athletes would have said great I'm +off to Vegas + + align:start position:0% +off to Vegas + + + align:start position:0% +off to Vegas +Bobby buddy you didn't he said well look + + align:start position:0% +Bobby buddy you didn't he said well look + + + align:start position:0% +Bobby buddy you didn't he said well look +I've got enough money right now but I + + align:start position:0% +I've got enough money right now but I + + + align:start position:0% +I've got enough money right now but I +might need the money later + + align:start position:0% +might need the money later + + + align:start position:0% +might need the money later +so instead why don't you defer the money + + align:start position:0% +so instead why don't you defer the money + + + align:start position:0% +so instead why don't you defer the money +at an 8% interest rate and pay me + + align:start position:0% +at an 8% interest rate and pay me + + + align:start position:0% +at an 8% interest rate and pay me +starting in 2011 when I'm getting close + + align:start position:0% +starting in 2011 when I'm getting close + + + align:start position:0% +starting in 2011 when I'm getting close +to retirement need the money they were + + align:start position:0% +to retirement need the money they were + + + align:start position:0% +to retirement need the money they were +like hey that's were like great we'll + + align:start position:0% +like hey that's were like great we'll + + + align:start position:0% +like hey that's were like great we'll +have to pay you now that's great well + + align:start position:0% +have to pay you now that's great well + + + align:start position:0% +have to pay you now that's great well +Bobby Bini Lea by the time his payments + + align:start position:0% +Bobby Bini Lea by the time his payments + + + align:start position:0% +Bobby Bini Lea by the time his payments +are to 2011 they've grown to 30 million + + align:start position:0% +are to 2011 they've grown to 30 million + + + align:start position:0% +are to 2011 they've grown to 30 million +dollars and every year on a certain day + + align:start position:0% +dollars and every year on a certain day + + + align:start position:0% +dollars and every year on a certain day +just pass the reason they call Bobby + + align:start position:0% +just pass the reason they call Bobby + + + align:start position:0% +just pass the reason they call Bobby +Bonilla de Bobby who's now like 7 years + + align:start position:0% +Bonilla de Bobby who's now like 7 years + + + align:start position:0% +Bonilla de Bobby who's now like 7 years +old gets a 1 gets a million dollar check + + align:start position:0% +old gets a 1 gets a million dollar check + + + align:start position:0% +old gets a 1 gets a million dollar check +from the Mets every year okay because + + align:start position:0% +from the Mets every year okay because + + + align:start position:0% +from the Mets every year okay because +there's patient enough to put this off + + align:start position:0% +there's patient enough to put this off + + + align:start position:0% +there's patient enough to put this off +and get the virtue of compounding okay + + align:start position:0% +and get the virtue of compounding okay + + + align:start position:0% +and get the virtue of compounding okay +so this is sort of if Bobby Bonita you + + align:start position:0% +so this is sort of if Bobby Bonita you + + + align:start position:0% +so this is sort of if Bobby Bonita you +know a stupid baseball player can do it + + align:start position:0% +know a stupid baseball player can do it + + + align:start position:0% +know a stupid baseball player can do it +you guys can do it so make sure that you + + align:start position:0% +you guys can do it so make sure that you + + + align:start position:0% +you guys can do it so make sure that you +guys are saving when you start jobs okay + + align:start position:0% +guys are saving when you start jobs okay + + + align:start position:0% +guys are saving when you start jobs okay +questions about that okay now let's + + align:start position:0% +questions about that okay now let's + + + align:start position:0% +questions about that okay now let's +let's let's let's get a little bit + + align:start position:0% +let's let's let's get a little bit + + + align:start position:0% +let's let's let's get a little bit +realistic and let's recognize that in + + align:start position:0% +realistic and let's recognize that in + + + align:start position:0% +realistic and let's recognize that in +life prices aren't constant but rather + + align:start position:0% +life prices aren't constant but rather + + + align:start position:0% +life prices aren't constant but rather +we have inflation and how does that + + align:start position:0% +we have inflation and how does that + + + align:start position:0% +we have inflation and how does that +affect our thinking here how does + + align:start position:0% +affect our thinking here how does + + + align:start position:0% +affect our thinking here how does +inflation affect the way we think about + + align:start position:0% +inflation affect the way we think about + + + align:start position:0% +inflation affect the way we think about +this problem well it turns out it + + align:start position:0% +this problem well it turns out it + + + align:start position:0% +this problem well it turns out it +actually adds one step but it's actually + + align:start position:0% +actually adds one step but it's actually + + + align:start position:0% +actually adds one step but it's actually +a pretty easy step to put in extra turns + + align:start position:0% +a pretty easy step to put in extra turns + + + align:start position:0% +a pretty easy step to put in extra turns +out you can add inflation without doing + + align:start position:0% +out you can add inflation without doing + + + align:start position:0% +out you can add inflation without doing +a whole lot of work so let's talk about + + align:start position:0% +a whole lot of work so let's talk about + + + align:start position:0% +a whole lot of work so let's talk about +first what inflation is inflation is the + + align:start position:0% +first what inflation is inflation is the + + + align:start position:0% +first what inflation is inflation is the +rise in the price level year-over-year + + align:start position:0% +rise in the price level year-over-year + + + align:start position:0% +rise in the price level year-over-year +tackling the inflation rate is a + + align:start position:0% +tackling the inflation rate is a + + + align:start position:0% +tackling the inflation rate is a +percentage concept it's the percent rise + + align:start position:0% +percentage concept it's the percent rise + + + align:start position:0% +percentage concept it's the percent rise +in the price level year after year and + + align:start position:0% +in the price level year after year and + + + align:start position:0% +in the price level year after year and +you might say the price level of what of + + align:start position:0% +you might say the price level of what of + + + align:start position:0% +you might say the price level of what of +a banana of a computer of what well what + + align:start position:0% +a banana of a computer of what well what + + + align:start position:0% +a banana of a computer of what well what +the government does is they form + + align:start position:0% +the government does is they form + + + align:start position:0% +the government does is they form +something called the Consumer Price + + align:start position:0% +something called the Consumer Price + + + align:start position:0% +something called the Consumer Price +Index the CPI talked about CPI yet okay + + align:start position:0% +Index the CPI talked about CPI yet okay + + + align:start position:0% +Index the CPI talked about CPI yet okay +I'm sorry I just and I hate repeating + + align:start position:0% +I'm sorry I just and I hate repeating + + + align:start position:0% +I'm sorry I just and I hate repeating +myself okay so they form something + + align:start position:0% +myself okay so they form something + + + align:start position:0% +myself okay so they form something +called the Consumer Price Index + + align:start position:0% +called the Consumer Price Index + + + align:start position:0% +called the Consumer Price Index +what's Tim Price Index literally the + + align:start position:0% +what's Tim Price Index literally the + + + align:start position:0% +what's Tim Price Index literally the +government every quarter I believe it is + + align:start position:0% +government every quarter I believe it is + + + align:start position:0% +government every quarter I believe it is +it may be every month goes out and gets + + align:start position:0% +it may be every month goes out and gets + + + align:start position:0% +it may be every month goes out and gets +the prices of a basket of hundreds of + + align:start position:0% +the prices of a basket of hundreds of + + + align:start position:0% +the prices of a basket of hundreds of +goods they literally say what does a + + align:start position:0% +goods they literally say what does a + + + align:start position:0% +goods they literally say what does a +banana cost this month compared to last + + align:start position:0% +banana cost this month compared to last + + + align:start position:0% +banana cost this month compared to last +month what does a laptop cost this month + + align:start position:0% +month what does a laptop cost this month + + + align:start position:0% +month what does a laptop cost this month +compared to last month etc so they go + + align:start position:0% +compared to last month etc so they go + + + align:start position:0% +compared to last month etc so they go +out and they price this bundle of goods + + align:start position:0% +out and they price this bundle of goods + + + align:start position:0% +out and they price this bundle of goods +and then literally they just asked how + + align:start position:0% +and then literally they just asked how + + + align:start position:0% +and then literally they just asked how +has the price that + + align:start position:0% +has the price that + + + align:start position:0% +has the price that +take a weighted average of that bundle + + align:start position:0% +take a weighted average of that bundle + + + align:start position:0% +take a weighted average of that bundle +where the weights are consumer spending + + align:start position:0% +where the weights are consumer spending + + + align:start position:0% +where the weights are consumer spending +so consumers spend a lot more if their + + align:start position:0% +so consumers spend a lot more if their + + + align:start position:0% +so consumers spend a lot more if their +income on housing than bananas so the + + align:start position:0% +income on housing than bananas so the + + + align:start position:0% +income on housing than bananas so the +price of housing gets a lot more weight + + align:start position:0% +price of housing gets a lot more weight + + + align:start position:0% +price of housing gets a lot more weight +in the CPI than as the price of bananas + + align:start position:0% +in the CPI than as the price of bananas + + + align:start position:0% +in the CPI than as the price of bananas +essentially a weighted average of prices + + align:start position:0% +essentially a weighted average of prices + + + align:start position:0% +essentially a weighted average of prices +in society and then that they cream + + align:start position:0% +in society and then that they cream + + + align:start position:0% +in society and then that they cream +index 1982 is normalized to one and they + + align:start position:0% +index 1982 is normalized to one and they + + + align:start position:0% +index 1982 is normalized to one and they +just say how much in percentage terms + + align:start position:0% +just say how much in percentage terms + + + align:start position:0% +just say how much in percentage terms +did that weighted average bundle go up + + align:start position:0% +did that weighted average bundle go up + + + align:start position:0% +did that weighted average bundle go up +in price okay and you can see that in + + align:start position:0% +in price okay and you can see that in + + + align:start position:0% +in price okay and you can see that in +Figure 17 one here's historical CPI so + + align:start position:0% +Figure 17 one here's historical CPI so + + + align:start position:0% +Figure 17 one here's historical CPI so +basically what you see is this is the + + align:start position:0% +basically what you see is this is the + + + align:start position:0% +basically what you see is this is the +level of the CPI which is sort of + + align:start position:0% +level of the CPI which is sort of + + + align:start position:0% +level of the CPI which is sort of +meaningless we care about his inflation + + align:start position:0% +meaningless we care about his inflation + + + align:start position:0% +meaningless we care about his inflation +which is the year-to-year percentage + + align:start position:0% +which is the year-to-year percentage + + + align:start position:0% +which is the year-to-year percentage +change in the CPI and what you can see + + align:start position:0% +change in the CPI and what you can see + + + align:start position:0% +change in the CPI and what you can see +is basically it's going up prices are + + align:start position:0% +is basically it's going up prices are + + + align:start position:0% +is basically it's going up prices are +going up it went up very steeply if you + + align:start position:0% +going up it went up very steeply if you + + + align:start position:0% +going up it went up very steeply if you +look from 1970 to 1980 the slope there + + align:start position:0% +look from 1970 to 1980 the slope there + + + align:start position:0% +look from 1970 to 1980 the slope there +is much higher than the slope before + + align:start position:0% +is much higher than the slope before + + + align:start position:0% +is much higher than the slope before +after we had very rapid inflation in the + + align:start position:0% +after we had very rapid inflation in the + + + align:start position:0% +after we had very rapid inflation in the +1970s it then and then since flattened + + align:start position:0% +1970s it then and then since flattened + + + align:start position:0% +1970s it then and then since flattened +and inflation has been much slower and + + align:start position:0% +and inflation has been much slower and + + + align:start position:0% +and inflation has been much slower and +inflation averaged is about three + + align:start position:0% +inflation averaged is about three + + + align:start position:0% +inflation averaged is about three +percent a year okay + + align:start position:0% +percent a year okay + + + align:start position:0% +percent a year okay +so basically that's how we measure + + align:start position:0% +so basically that's how we measure + + + align:start position:0% +so basically that's how we measure +inflation now the question is how does + + align:start position:0% +inflation now the question is how does + + + align:start position:0% +inflation now the question is how does +that affect our thinking about present + + align:start position:0% +that affect our thinking about present + + + align:start position:0% +that affect our thinking about present +value if there's actually inflation and + + align:start position:0% +value if there's actually inflation and + + + align:start position:0% +value if there's actually inflation and +the bottom line is we don't care about + + align:start position:0% +the bottom line is we don't care about + + + align:start position:0% +the bottom line is we don't care about +dollars we care about how many goods we + + align:start position:0% +dollars we care about how many goods we + + + align:start position:0% +dollars we care about how many goods we +can buy therefore it doesn't matter + + align:start position:0% +can buy therefore it doesn't matter + + + align:start position:0% +can buy therefore it doesn't matter +what's happening to how much money we + + align:start position:0% +what's happening to how much money we + + + align:start position:0% +what's happening to how much money we +have it matters what's happened - how + + align:start position:0% +have it matters what's happened - how + + + align:start position:0% +have it matters what's happened - how +many Goods we can buy therefore what we + + align:start position:0% +many Goods we can buy therefore what we + + + align:start position:0% +many Goods we can buy therefore what we +care about is not what we call the + + align:start position:0% +care about is not what we call the + + + align:start position:0% +care about is not what we call the +nominal interest rate we care about we + + align:start position:0% +nominal interest rate we care about we + + + align:start position:0% +nominal interest rate we care about we +call the real interest rate or which we + + align:start position:0% +call the real interest rate or which we + + + align:start position:0% +call the real interest rate or which we +define as the nominal interest rate + + align:start position:0% +define as the nominal interest rate + + + align:start position:0% +define as the nominal interest rate +which is well been talking about we see + + align:start position:0% +which is well been talking about we see + + + align:start position:0% +which is well been talking about we see +advertised in a bank - the rate of + + align:start position:0% +advertised in a bank - the rate of + + + align:start position:0% +advertised in a bank - the rate of +inflation which for some reason we use + + align:start position:0% +inflation which for some reason we use + + + align:start position:0% +inflation which for some reason we use +PI even though that's also profits so + + align:start position:0% +PI even though that's also profits so + + + align:start position:0% +PI even though that's also profits so +sorry about that okay so we define the + + align:start position:0% +sorry about that okay so we define the + + + align:start position:0% +sorry about that okay so we define the +real interest rate as the nominal + + align:start position:0% +real interest rate as the nominal + + + align:start position:0% +real interest rate as the nominal +interest rate - the inflation rate okay + + align:start position:0% +interest rate - the inflation rate okay + + + align:start position:0% +interest rate - the inflation rate okay +the nominal and real estate nominal rate + + align:start position:0% +the nominal and real estate nominal rate + + + align:start position:0% +the nominal and real estate nominal rate +- the inflation rate and what the real + + align:start position:0% +- the inflation rate and what the real + + + align:start position:0% +- the inflation rate and what the real +interest rate measures is how much more + + align:start position:0% +interest rate measures is how much more + + + align:start position:0% +interest rate measures is how much more +I have in time in terms of goods I can + + align:start position:0% +I have in time in terms of goods I can + + + align:start position:0% +I have in time in terms of goods I can +consume not how much more I have in + + align:start position:0% +consume not how much more I have in + + + align:start position:0% +consume not how much more I have in +terms of dollars which actually in the + + align:start position:0% +terms of dollars which actually in the + + + align:start position:0% +terms of dollars which actually in the +end doesn't matter okay so suppose + + align:start position:0% +end doesn't matter okay so suppose + + + align:start position:0% +end doesn't matter okay so suppose +that I'm gonna save $100 at a 10% + + align:start position:0% +that I'm gonna save $100 at a 10% + + + align:start position:0% +that I'm gonna save $100 at a 10% +interest rate it's go simple example + + align:start position:0% +interest rate it's go simple example + + + align:start position:0% +interest rate it's go simple example +they have $100 or 10% interest rate okay + + align:start position:0% +they have $100 or 10% interest rate okay + + + align:start position:0% +they have $100 or 10% interest rate okay +what I then next you'll have one hundred + + align:start position:0% +what I then next you'll have one hundred + + + align:start position:0% +what I then next you'll have one hundred +and ten dollars but that's irrelevant + + align:start position:0% +and ten dollars but that's irrelevant + + + align:start position:0% +and ten dollars but that's irrelevant +what I want to know is how many Goods + + align:start position:0% +what I want to know is how many Goods + + + align:start position:0% +what I want to know is how many Goods +can I buy next year so for example let's + + align:start position:0% +can I buy next year so for example let's + + + align:start position:0% +can I buy next year so for example let's +say you spend all your money on skittles + + align:start position:0% +say you spend all your money on skittles + + + align:start position:0% +say you spend all your money on skittles +that's all you buy okay and let's say + + align:start position:0% +that's all you buy okay and let's say + + + align:start position:0% +that's all you buy okay and let's say +skittles cost $1 this year and there's + + align:start position:0% +skittles cost $1 this year and there's + + + align:start position:0% +skittles cost $1 this year and there's +no inflation those cost $1 next year + + align:start position:0% +no inflation those cost $1 next year + + + align:start position:0% +no inflation those cost $1 next year +then what that means with a 10% interest + + align:start position:0% +then what that means with a 10% interest + + + align:start position:0% +then what that means with a 10% interest +rate is you can buy ten more bags of + + align:start position:0% +rate is you can buy ten more bags of + + + align:start position:0% +rate is you can buy ten more bags of +Skittles next year this year your + + align:start position:0% +Skittles next year this year your + + + align:start position:0% +Skittles next year this year your +hundred dollars could buy you a hundred + + align:start position:0% +hundred dollars could buy you a hundred + + + align:start position:0% +hundred dollars could buy you a hundred +bags of Skittles next year your hundred + + align:start position:0% +bags of Skittles next year your hundred + + + align:start position:0% +bags of Skittles next year your hundred +ten dollars can buy 110 bags of Skittles + + align:start position:0% +ten dollars can buy 110 bags of Skittles + + + align:start position:0% +ten dollars can buy 110 bags of Skittles +so you are ten percent richer but now + + align:start position:0% +so you are ten percent richer but now + + + align:start position:0% +so you are ten percent richer but now +let's say the price of skittles goes up + + align:start position:0% +let's say the price of skittles goes up + + + align:start position:0% +let's say the price of skittles goes up +10 percent well what that means is you + + align:start position:0% +10 percent well what that means is you + + + align:start position:0% +10 percent well what that means is you +can only buy the same amount of skittles + + align:start position:0% +can only buy the same amount of skittles + + + align:start position:0% +can only buy the same amount of skittles +next year you could buy this year you + + align:start position:0% +next year you could buy this year you + + + align:start position:0% +next year you could buy this year you +could buy a hundred bags this year and + + align:start position:0% +could buy a hundred bags this year and + + + align:start position:0% +could buy a hundred bags this year and +100 bags next year so it doesn't matter + + align:start position:0% +100 bags next year so it doesn't matter + + + align:start position:0% +100 bags next year so it doesn't matter +you have a hundred and ten dollars next + + align:start position:0% +you have a hundred and ten dollars next + + + align:start position:0% +you have a hundred and ten dollars next +year who cares you can only get the same + + align:start position:0% +year who cares you can only get the same + + + align:start position:0% +year who cares you can only get the same +amount of skittles what you care about + + align:start position:0% +amount of skittles what you care about + + + align:start position:0% +amount of skittles what you care about +is the goods you can buy note on utility + + align:start position:0% +is the goods you can buy note on utility + + + align:start position:0% +is the goods you can buy note on utility +wouldn't put dollars utility function we + + align:start position:0% +wouldn't put dollars utility function we + + + align:start position:0% +wouldn't put dollars utility function we +put consumption so the interest rate you + + align:start position:0% +put consumption so the interest rate you + + + align:start position:0% +put consumption so the interest rate you +care about is the real interest rate if + + align:start position:0% +care about is the real interest rate if + + + align:start position:0% +care about is the real interest rate if +the nominal in straight is ten percent + + align:start position:0% +the nominal in straight is ten percent + + + align:start position:0% +the nominal in straight is ten percent +but inflation is ten percent then the + + align:start position:0% +but inflation is ten percent then the + + + align:start position:0% +but inflation is ten percent then the +real interest rate is zero you can't buy + + align:start position:0% +real interest rate is zero you can't buy + + + align:start position:0% +real interest rate is zero you can't buy +any more Goods next year all the money + + align:start position:0% +any more Goods next year all the money + + + align:start position:0% +any more Goods next year all the money +you made by putting the bank got eaten + + align:start position:0% +you made by putting the bank got eaten + + + align:start position:0% +you made by putting the bank got eaten +up by how much more expensive things are + + align:start position:0% +up by how much more expensive things are + + + align:start position:0% +up by how much more expensive things are +so what that means is all the math we've + + align:start position:0% +so what that means is all the math we've + + + align:start position:0% +so what that means is all the math we've +done and everything we'll talk about it + + align:start position:0% +done and everything we'll talk about it + + + align:start position:0% +done and everything we'll talk about it +all goes through you just need to be + + align:start position:0% +all goes through you just need to be + + + align:start position:0% +all goes through you just need to be +thinking about using the real interest + + align:start position:0% +thinking about using the real interest + + + align:start position:0% +thinking about using the real interest +rate not the nominal interest rate okay + + align:start position:0% +rate not the nominal interest rate okay + + + align:start position:0% +rate not the nominal interest rate okay +but otherwise everything we've done is + + align:start position:0% +but otherwise everything we've done is + + + align:start position:0% +but otherwise everything we've done is +goes through you just need to + + align:start position:0% +goes through you just need to + + + align:start position:0% +goes through you just need to +essentially think about this in terms of + + align:start position:0% +essentially think about this in terms of + + + align:start position:0% +essentially think about this in terms of +how many goods you can buy not how much + + align:start position:0% +how many goods you can buy not how much + + + align:start position:0% +how many goods you can buy not how much +money you have now this isn't quite let + + align:start position:0% +money you have now this isn't quite let + + + align:start position:0% +money you have now this isn't quite let +me just take two minutes and do a little + + align:start position:0% +me just take two minutes and do a little + + + align:start position:0% +me just take two minutes and do a little +macroeconomics this isn't quite as + + align:start position:0% +macroeconomics this isn't quite as + + + align:start position:0% +macroeconomics this isn't quite as +simple as it sounds because of course + + align:start position:0% +simple as it sounds because of course + + + align:start position:0% +simple as it sounds because of course +you see in the bank I in the bank window + + align:start position:0% +you see in the bank I in the bank window + + + align:start position:0% +you see in the bank I in the bank window +I you don't see pie you don't see + + align:start position:0% +I you don't see pie you don't see + + + align:start position:0% +I you don't see pie you don't see +inflation that's what we revealed + + align:start position:0% +inflation that's what we revealed + + + align:start position:0% +inflation that's what we revealed +ex-post + + align:start position:0% +ex-post + + + align:start position:0% +ex-post +so really technically you don't have to + + align:start position:0% +so really technically you don't have to + + + align:start position:0% +so really technically you don't have to +know this is just for those who care + + align:start position:0% +know this is just for those who care + + + align:start position:0% +know this is just for those who care +it's just the test + + align:start position:0% +it's just the test + + + align:start position:0% +it's just the test +technically what you really want is + + align:start position:0% +technically what you really want is + + + align:start position:0% +technically what you really want is +expected inflation right when you think + + align:start position:0% +expected inflation right when you think + + + align:start position:0% +expected inflation right when you think +I'm putting in the money in the bank you + + align:start position:0% +I'm putting in the money in the bank you + + + align:start position:0% +I'm putting in the money in the bank you +know you learn 3% the realist rate is + + align:start position:0% +know you learn 3% the realist rate is + + + align:start position:0% +know you learn 3% the realist rate is +that - what you think inflation is going + + align:start position:0% +that - what you think inflation is going + + + align:start position:0% +that - what you think inflation is going +to be + + align:start position:0% +to be + + + align:start position:0% +to be +right so it actually becomes complicated + + align:start position:0% +right so it actually becomes complicated + + + align:start position:0% +right so it actually becomes complicated +it's not as simple ex-post it's easy to + + align:start position:0% +it's not as simple ex-post it's easy to + + + align:start position:0% +it's not as simple ex-post it's easy to +find the real interest rate ex ante it's + + align:start position:0% +find the real interest rate ex ante it's + + + align:start position:0% +find the real interest rate ex ante it's +not so easy because depends on what you + + align:start position:0% +not so easy because depends on what you + + + align:start position:0% +not so easy because depends on what you +think inflation is going to be there's + + align:start position:0% +think inflation is going to be there's + + + align:start position:0% +think inflation is going to be there's +some tricks there there's also a bunch + + align:start position:0% +some tricks there there's also a bunch + + + align:start position:0% +some tricks there there's also a bunch +of tricks and measuring the inflation + + align:start position:0% +of tricks and measuring the inflation + + + align:start position:0% +of tricks and measuring the inflation +rate so for example like I said the + + align:start position:0% +rate so for example like I said the + + + align:start position:0% +rate so for example like I said the +Bureau of Labor Statistics goes out and + + align:start position:0% +Bureau of Labor Statistics goes out and + + + align:start position:0% +Bureau of Labor Statistics goes out and +has a bundle of 600 goods it gets their + + align:start position:0% +has a bundle of 600 goods it gets their + + + align:start position:0% +has a bundle of 600 goods it gets their +prices but what is it good I mean a + + align:start position:0% +prices but what is it good I mean a + + + align:start position:0% +prices but what is it good I mean a +bananas a banana but a laptop what the + + align:start position:0% +bananas a banana but a laptop what the + + + align:start position:0% +bananas a banana but a laptop what the +hell is a laptop how much RAM does it + + align:start position:0% +hell is a laptop how much RAM does it + + + align:start position:0% +hell is a laptop how much RAM does it +have what's the graphics card + + align:start position:0% +have what's the graphics card + + + align:start position:0% +have what's the graphics card +you know how faith is to display well + + align:start position:0% +you know how faith is to display well + + + align:start position:0% +you know how faith is to display well +the Bureau logistics doesn't go out and + + align:start position:0% +the Bureau logistics doesn't go out and + + + align:start position:0% +the Bureau logistics doesn't go out and +price literally hundreds of laptops at + + align:start position:0% +price literally hundreds of laptops at + + + align:start position:0% +price literally hundreds of laptops at +prices one or two and the problem with + + align:start position:0% +prices one or two and the problem with + + + align:start position:0% +prices one or two and the problem with +that is the following let's say you find + + align:start position:0% +that is the following let's say you find + + + align:start position:0% +that is the following let's say you find +that today a laptop is a thousand and + + align:start position:0% +that today a laptop is a thousand and + + + align:start position:0% +that today a laptop is a thousand and +tomorrow it's 1,500 but it can do let's + + align:start position:0% +tomorrow it's 1,500 but it can do let's + + + align:start position:0% +tomorrow it's 1,500 but it can do let's +say today laptops a thousand and + + align:start position:0% +say today laptops a thousand and + + + align:start position:0% +say today laptops a thousand and +tomorrow it's 1500 but it can do a ton + + align:start position:0% +tomorrow it's 1500 but it can do a ton + + + align:start position:0% +tomorrow it's 1500 but it can do a ton +more stuff well we would say inflation + + align:start position:0% +more stuff well we would say inflation + + + align:start position:0% +more stuff well we would say inflation +is 50% but that's not really right + + align:start position:0% +is 50% but that's not really right + + + align:start position:0% +is 50% but that's not really right +because the good you're consuming is not + + align:start position:0% +because the good you're consuming is not + + + align:start position:0% +because the good you're consuming is not +the laptop it's the computing ability of + + align:start position:0% +the laptop it's the computing ability of + + + align:start position:0% +the laptop it's the computing ability of +the laptop and that's gone up so to say + + align:start position:0% +the laptop and that's gone up so to say + + + align:start position:0% +the laptop and that's gone up so to say +inflation 50% is wrong inflation 50% - + + align:start position:0% +inflation 50% is wrong inflation 50% - + + + align:start position:0% +inflation 50% is wrong inflation 50% - +the quality improvement of the better + + align:start position:0% +the quality improvement of the better + + + align:start position:0% +the quality improvement of the better +laptop you got think of it another way + + align:start position:0% +laptop you got think of it another way + + + align:start position:0% +laptop you got think of it another way +imagine laptop prices didn't go up but + + align:start position:0% +imagine laptop prices didn't go up but + + + align:start position:0% +imagine laptop prices didn't go up but +RAM doubled okay would you say you're no + + align:start position:0% +RAM doubled okay would you say you're no + + + align:start position:0% +RAM doubled okay would you say you're no +better off buying a laptop with twice as + + align:start position:0% +better off buying a laptop with twice as + + + align:start position:0% +better off buying a laptop with twice as +much RAM at the same price no you're + + align:start position:0% +much RAM at the same price no you're + + + align:start position:0% +much RAM at the same price no you're +better off but about our inflation + + align:start position:0% +better off but about our inflation + + + align:start position:0% +better off but about our inflation +concept would say no you're the same + + align:start position:0% +concept would say no you're the same + + + align:start position:0% +concept would say no you're the same +often so the trick here is it simple and + + align:start position:0% +often so the trick here is it simple and + + + align:start position:0% +often so the trick here is it simple and +practice and we'll pretend as simple to + + align:start position:0% +practice and we'll pretend as simple to + + + align:start position:0% +practice and we'll pretend as simple to +say are as I - PI but two tricks a it's + + align:start position:0% +say are as I - PI but two tricks a it's + + + align:start position:0% +say are as I - PI but two tricks a it's +expected PI which is hard to guess and + + align:start position:0% +expected PI which is hard to guess and + + + align:start position:0% +expected PI which is hard to guess and +be inflation is really hard to measure + + align:start position:0% +be inflation is really hard to measure + + + align:start position:0% +be inflation is really hard to measure +because there's things like quality bias + + align:start position:0% +because there's things like quality bias + + + align:start position:0% +because there's things like quality bias +and other things there's a whole field + + align:start position:0% +and other things there's a whole field + + + align:start position:0% +and other things there's a whole field +de macroeconomics worrying about + + align:start position:0% +de macroeconomics worrying about + + + align:start position:0% +de macroeconomics worrying about +inflation measurement so let's spend a + + align:start position:0% +inflation measurement so let's spend a + + + align:start position:0% +inflation measurement so let's spend a +lot of time on it but it's just sort of + + align:start position:0% +lot of time on it but it's just sort of + + + align:start position:0% +lot of time on it but it's just sort of +the kind of interesting we tweak just to + + align:start position:0% +the kind of interesting we tweak just to + + + align:start position:0% +the kind of interesting we tweak just to +sort of talk about how sort of at high + + align:start position:0% +sort of talk about how sort of at high + + + align:start position:0% +sort of talk about how sort of at high +level we go things here like everything + + align:start position:0% +level we go things here like everything + + + align:start position:0% +level we go things here like everything +else in this class largely we get it + + align:start position:0% +else in this class largely we get it + + + align:start position:0% +else in this class largely we get it +right largely expected inflation is not + + align:start position:0% +right largely expected inflation is not + + + align:start position:0% +right largely expected inflation is not +too badly modelled by last year's + + align:start position:0% +too badly modelled by last year's + + + align:start position:0% +too badly modelled by last year's +inflation and quality bias bias we can + + align:start position:0% +inflation and quality bias bias we can + + + align:start position:0% +inflation and quality bias bias we can +model it stuff so this isn't a bad model + + align:start position:0% +model it stuff so this isn't a bad model + + + align:start position:0% +model it stuff so this isn't a bad model +but it just sort of points to some of + + align:start position:0% +but it just sort of points to some of + + + align:start position:0% +but it just sort of points to some of +the subtleties you have to deal with a + + align:start position:0% +the subtleties you have to deal with a + + + align:start position:0% +the subtleties you have to deal with a +reality when you try to implement these + + align:start position:0% +reality when you try to implement these + + + align:start position:0% +reality when you try to implement these +basic sort of formulations okay now + + align:start position:0% +basic sort of formulations okay now + + + align:start position:0% +basic sort of formulations okay now +with that in mind I'm gonna now say + + align:start position:0% +with that in mind I'm gonna now say + + + align:start position:0% +with that in mind I'm gonna now say +let's assume inflation zero again okay + + align:start position:0% +let's assume inflation zero again okay + + + align:start position:0% +let's assume inflation zero again okay +so we'll go back and use I and we'll use + + align:start position:0% +so we'll go back and use I and we'll use + + + align:start position:0% +so we'll go back and use I and we'll use +I interchangeably with our for the rest + + align:start position:0% +I interchangeably with our for the rest + + + align:start position:0% +I interchangeably with our for the rest +of this course okay unless asked + + align:start position:0% +of this course okay unless asked + + + align:start position:0% +of this course okay unless asked +differently unless told differently + + align:start position:0% +differently unless told differently + + + align:start position:0% +differently unless told differently +assume inflation zero so INR and are + + align:start position:0% +assume inflation zero so INR and are + + + align:start position:0% +assume inflation zero so INR and are +interchangeable with that in mind let's + + align:start position:0% +interchangeable with that in mind let's + + + align:start position:0% +interchangeable with that in mind let's +go to the next topic which is taking + + align:start position:0% +go to the next topic which is taking + + + align:start position:0% +go to the next topic which is taking +these tools how do we model choices over + + align:start position:0% +these tools how do we model choices over + + + align:start position:0% +these tools how do we model choices over +time + + align:start position:0% + + + + align:start position:0% + +how do people model how do people make + + align:start position:0% +how do people model how do people make + + + align:start position:0% +how do people model how do people make +decisions over time and there's a simple + + align:start position:0% +decisions over time and there's a simple + + + align:start position:0% +decisions over time and there's a simple +int so this is tricky because if I said + + align:start position:0% +int so this is tricky because if I said + + + align:start position:0% +int so this is tricky because if I said +to you hey I'm gonna give you what do + + align:start position:0% +to you hey I'm gonna give you what do + + + align:start position:0% +to you hey I'm gonna give you what do +you want $30 or $50 you'd say I want $50 + + align:start position:0% +you want $30 or $50 you'd say I want $50 + + + align:start position:0% +you want $30 or $50 you'd say I want $50 +but actually shouldn't say that you + + align:start position:0% +but actually shouldn't say that you + + + align:start position:0% +but actually shouldn't say that you +should say over what period of time by + + align:start position:0% +should say over what period of time by + + + align:start position:0% +should say over what period of time by +getting the 30 and over what period of + + align:start position:0% +getting the 30 and over what period of + + + align:start position:0% +getting the 30 and over what period of +time by getting the 50 if it's today I + + align:start position:0% +time by getting the 50 if it's today I + + + align:start position:0% +time by getting the 50 if it's today I +want 50 but then 50 is 20 years in the + + align:start position:0% +want 50 but then 50 is 20 years in the + + + align:start position:0% +want 50 but then 50 is 20 years in the +future in the 30s today I might want the + + align:start position:0% +future in the 30s today I might want the + + + align:start position:0% +future in the 30s today I might want the +30 what that means is you have to + + align:start position:0% +30 what that means is you have to + + + align:start position:0% +30 what that means is you have to +evaluate choices in present value terms + + align:start position:0% +evaluate choices in present value terms + + + align:start position:0% +evaluate choices in present value terms +you can't just add up the money you have + + align:start position:0% +you can't just add up the money you have + + + align:start position:0% +you can't just add up the money you have +to evaluate those choices in present + + align:start position:0% +to evaluate those choices in present + + + align:start position:0% +to evaluate those choices in present +value terms and then you need to pick + + align:start position:0% +value terms and then you need to pick + + + align:start position:0% +value terms and then you need to pick +the option with the highest present + + align:start position:0% +the option with the highest present + + + align:start position:0% +the option with the highest present +value so let's see let's come back to + + align:start position:0% +value so let's see let's come back to + + + align:start position:0% +value so let's see let's come back to +athletes because I've let a contracts + + align:start position:0% +athletes because I've let a contracts + + + align:start position:0% +athletes because I've let a contracts +deal with this all the time let's + + align:start position:0% +deal with this all the time let's + + + align:start position:0% +deal with this all the time let's +imagine athlean considering two + + align:start position:0% +imagine athlean considering two + + + align:start position:0% +imagine athlean considering two +different contracts okay contract one + + align:start position:0% +different contracts okay contract one + + + align:start position:0% +different contracts okay contract one +pays contract a pays a million dollars + + align:start position:0% +pays contract a pays a million dollars + + + align:start position:0% +pays contract a pays a million dollars +today contract be okay + + align:start position:0% +today contract be okay + + + align:start position:0% +today contract be okay +pays 500,000 today and 1.5 million in + + align:start position:0% +pays 500,000 today and 1.5 million in + + + align:start position:0% +pays 500,000 today and 1.5 million in +ten years okay now when you read in the + + align:start position:0% +ten years okay now when you read in the + + + align:start position:0% +ten years okay now when you read in the +newspaper you'll see this guy got off + + align:start position:0% +newspaper you'll see this guy got off + + + align:start position:0% +newspaper you'll see this guy got off +for a million this guy got off for two + + align:start position:0% +for a million this guy got off for two + + + align:start position:0% +for a million this guy got off for two +million + + align:start position:0% +million + + + align:start position:0% +million +that's what newspaper will say but + + align:start position:0% +that's what newspaper will say but + + + align:start position:0% +that's what newspaper will say but +that's wrong because these are painted + + align:start position:0% +that's wrong because these are painted + + + align:start position:0% +that's wrong because these are painted +different periods of times that are + + align:start position:0% +different periods of times that are + + + align:start position:0% +different periods of times that are +different amounts indeed + + align:start position:0% +different amounts indeed + + + align:start position:0% +different amounts indeed +the present value the first contract is + + align:start position:0% +the present value the first contract is + + + align:start position:0% +the present value the first contract is +what 1 million dollars it's today what's + + align:start position:0% +what 1 million dollars it's today what's + + + align:start position:0% +what 1 million dollars it's today what's +the present value the second contract + + align:start position:0% +the present value the second contract + + + align:start position:0% +the present value the second contract +someone tell me how I'd write that down + + align:start position:0% +someone tell me how I'd write that down + + + align:start position:0% +someone tell me how I'd write that down +I'd write down the present value the + + align:start position:0% +I'd write down the present value the + + + align:start position:0% +I'd write down the present value the +second contract + + align:start position:0% + + + + align:start position:0% + +exactly what you want I'll st. straight + + align:start position:0% +exactly what you want I'll st. straight + + + align:start position:0% +exactly what you want I'll st. straight +to the 10th right because we're getting + + align:start position:0% +to the 10th right because we're getting + + + align:start position:0% +to the 10th right because we're getting +in 10 years okay + + align:start position:0% +in 10 years okay + + + align:start position:0% +in 10 years okay +so essentially um that means that + + align:start position:0% +so essentially um that means that + + + align:start position:0% +so essentially um that means that +whether it's a better deal or not + + align:start position:0% +whether it's a better deal or not + + + align:start position:0% +whether it's a better deal or not +depends on the interest rate indeed if + + align:start position:0% +depends on the interest rate indeed if + + + align:start position:0% +depends on the interest rate indeed if +the interest is 7% and this rate is 7% + + align:start position:0% +the interest is 7% and this rate is 7% + + + align:start position:0% +the interest is 7% and this rate is 7% +this has a present value of 1.3 million + + align:start position:0% +this has a present value of 1.3 million + + + align:start position:0% +this has a present value of 1.3 million +so it's a good deal if the interest rate + + align:start position:0% +so it's a good deal if the interest rate + + + align:start position:0% +so it's a good deal if the interest rate +was 14% then this deal would have a + + align:start position:0% +was 14% then this deal would have a + + + align:start position:0% +was 14% then this deal would have a +present value of 0.9 million so it's a + + align:start position:0% +present value of 0.9 million so it's a + + + align:start position:0% +present value of 0.9 million so it's a +worse deal so whether or not this a + + align:start position:0% +worse deal so whether or not this a + + + align:start position:0% +worse deal so whether or not this a +better or worse deal depends on the + + align:start position:0% +better or worse deal depends on the + + + align:start position:0% +better or worse deal depends on the +interest rate why is that + + align:start position:0% +interest rate why is that + + + align:start position:0% +interest rate why is that +why is this a worse deal the higher the + + align:start position:0% +why is this a worse deal the higher the + + + align:start position:0% +why is this a worse deal the higher the +interest rate yeah exactly + + align:start position:0% +interest rate yeah exactly + + + align:start position:0% +interest rate yeah exactly +you could have invested it earlier got + + align:start position:0% +you could have invested it earlier got + + + align:start position:0% +you could have invested it earlier got +in the compounding and had way more + + align:start position:0% +in the compounding and had way more + + + align:start position:0% +in the compounding and had way more +money in 10 years so the higher the + + align:start position:0% +money in 10 years so the higher the + + + align:start position:0% +money in 10 years so the higher the +interest rate the more you want to get + + align:start position:0% +interest rate the more you want to get + + + align:start position:0% +interest rate the more you want to get +your money upfront and save it the less + + align:start position:0% +your money upfront and save it the less + + + align:start position:0% +your money upfront and save it the less +valuable is money in the future okay now + + align:start position:0% +valuable is money in the future okay now + + + align:start position:0% +valuable is money in the future okay now +so essentially what this says you have + + align:start position:0% +so essentially what this says you have + + + align:start position:0% +so essentially what this says you have +to always use present value to bring + + align:start position:0% +to always use present value to bring + + + align:start position:0% +to always use present value to bring +things into current dollars now this is + + align:start position:0% +things into current dollars now this is + + + align:start position:0% +things into current dollars now this is +not an abstract concept + + align:start position:0% +not an abstract concept + + + align:start position:0% +not an abstract concept +let's take max scherzer who's a picture + + align:start position:0% +let's take max scherzer who's a picture + + + align:start position:0% +let's take max scherzer who's a picture +with the Washington Nationals max + + align:start position:0% +with the Washington Nationals max + + + align:start position:0% +with the Washington Nationals max +scherzer um a couple years ago signed a + + align:start position:0% +scherzer um a couple years ago signed a + + + align:start position:0% +scherzer um a couple years ago signed a +seven-year two hundred a seven-year two + + align:start position:0% +seven-year two hundred a seven-year two + + + align:start position:0% +seven-year two hundred a seven-year two +hundred and ten million dollar contract + + align:start position:0% +hundred and ten million dollar contract + + + align:start position:0% +hundred and ten million dollar contract +which he was able to brag was the + + align:start position:0% +which he was able to brag was the + + + align:start position:0% +which he was able to brag was the +second-highest ever signed by a pitcher + + align:start position:0% +second-highest ever signed by a pitcher + + + align:start position:0% +second-highest ever signed by a pitcher +and the tenth highest contract ever + + align:start position:0% +and the tenth highest contract ever + + + align:start position:0% +and the tenth highest contract ever +signed by any baseball player seven + + align:start position:0% +signed by any baseball player seven + + + align:start position:0% +signed by any baseball player seven +years to ten but in fact um that + + align:start position:0% +years to ten but in fact um that + + + align:start position:0% +years to ten but in fact um that +contract was not we're gonna pay you + + align:start position:0% +contract was not we're gonna pay you + + + align:start position:0% +contract was not we're gonna pay you +thirty million dollars a year for seven + + align:start position:0% +thirty million dollars a year for seven + + + align:start position:0% +thirty million dollars a year for seven +years it was we're gonna pay you 15 + + align:start position:0% +years it was we're gonna pay you 15 + + + align:start position:0% +years it was we're gonna pay you 15 +million dollars a year for 14 years + + align:start position:0% +million dollars a year for 14 years + + + align:start position:0% +million dollars a year for 14 years +you're gonna play him for only seven + + align:start position:0% +you're gonna play him for only seven + + + align:start position:0% +you're gonna play him for only seven +we're gonna pay over fourteen years so + + align:start position:0% +we're gonna pay over fourteen years so + + + align:start position:0% +we're gonna pay over fourteen years so +in fact in present value terms it was + + align:start position:0% +in fact in present value terms it was + + + align:start position:0% +in fact in present value terms it was +worth somewhat less if you use the + + align:start position:0% +worth somewhat less if you use the + + + align:start position:0% +worth somewhat less if you use the +current interest rate when you signed it + + align:start position:0% +current interest rate when you signed it + + + align:start position:0% +current interest rate when you signed it +which is about four point seven percent + + align:start position:0% +which is about four point seven percent + + + align:start position:0% +which is about four point seven percent +it was only worth actually 166 million + + align:start position:0% +it was only worth actually 166 million + + + align:start position:0% +it was only worth actually 166 million +not too shabby + + align:start position:0% +not too shabby + + + align:start position:0% +not too shabby +but suddenly drops the 20th most + + align:start position:0% +but suddenly drops the 20th most + + + align:start position:0% +but suddenly drops the 20th most +valuable baseball contracting about + + align:start position:0% +valuable baseball contracting about + + + align:start position:0% +valuable baseball contracting about +fourth among pitchers so Max Scherzer + + align:start position:0% +fourth among pitchers so Max Scherzer + + + align:start position:0% +fourth among pitchers so Max Scherzer +was able to feel better about himself + + align:start position:0% +was able to feel better about himself + + + align:start position:0% +was able to feel better about himself +that he signed to it you know this + + align:start position:0% +that he signed to it you know this + + + align:start position:0% +that he signed to it you know this +valuable contract but in fact it was + + align:start position:0% +valuable contract but in fact it was + + + align:start position:0% +valuable contract but in fact it was +worth less than he thought me shed no + + align:start position:0% +worth less than he thought me shed no + + + align:start position:0% +worth less than he thought me shed no +tears from Max Scherzer he's doing fine + + align:start position:0% +tears from Max Scherzer he's doing fine + + + align:start position:0% +tears from Max Scherzer he's doing fine +but it was worth less than he thought + + align:start position:0% +but it was worth less than he thought + + + align:start position:0% +but it was worth less than he thought +or maybe one example it's more in our + + align:start position:0% +or maybe one example it's more in our + + + align:start position:0% +or maybe one example it's more in our +mind with the Mega Millions think about + + align:start position:0% +mind with the Mega Millions think about + + + align:start position:0% +mind with the Mega Millions think about +a lottery winner so if a Mega Millions + + align:start position:0% +a lottery winner so if a Mega Millions + + + align:start position:0% +a lottery winner so if a Mega Millions +winner gets two hundred ninety million + + align:start position:0% +winner gets two hundred ninety million + + + align:start position:0% +winner gets two hundred ninety million +dollars hey which sounds like a great + + align:start position:0% +dollars hey which sounds like a great + + + align:start position:0% +dollars hey which sounds like a great +deal that's paid out over 20 years so + + align:start position:0% +deal that's paid out over 20 years so + + + align:start position:0% +deal that's paid out over 20 years so +it's not two hundred ninety million + + align:start position:0% +it's not two hundred ninety million + + + align:start position:0% +it's not two hundred ninety million +dollars it's fourteen and a half million + + align:start position:0% +dollars it's fourteen and a half million + + + align:start position:0% +dollars it's fourteen and a half million +for each of 20 years so in present value + + align:start position:0% +for each of 20 years so in present value + + + align:start position:0% +for each of 20 years so in present value +terms if we think about a 7% interest + + align:start position:0% +terms if we think about a 7% interest + + + align:start position:0% +terms if we think about a 7% interest +rate then that's not 290 million 164 + + align:start position:0% +rate then that's not 290 million 164 + + + align:start position:0% +rate then that's not 290 million 164 +million once again not too shabby okay + + align:start position:0% +million once again not too shabby okay + + + align:start position:0% +million once again not too shabby okay +but a lot less than the advertised + + align:start position:0% +but a lot less than the advertised + + + align:start position:0% +but a lot less than the advertised +amount so we have to take these dollars + + align:start position:0% +amount so we have to take these dollars + + + align:start position:0% +amount so we have to take these dollars +and put them in present value okay so + + align:start position:0% +and put them in present value okay so + + + align:start position:0% +and put them in present value okay so +now now here's an interesting question + + align:start position:0% +now now here's an interesting question + + + align:start position:0% +now now here's an interesting question +for that if you look at the recent + + align:start position:0% +for that if you look at the recent + + + align:start position:0% +for that if you look at the recent +lottery okay you had a choice of the + + align:start position:0% +lottery okay you had a choice of the + + + align:start position:0% +lottery okay you had a choice of the +person one person one point six billion + + align:start position:0% +person one person one point six billion + + + align:start position:0% +person one person one point six billion +one person one down person in South + + align:start position:0% +one person one down person in South + + + align:start position:0% +one person one down person in South +Carolina on that and they were given a + + align:start position:0% +Carolina on that and they were given a + + + align:start position:0% +Carolina on that and they were given a +choice of the 1.6 billion which is paid + + align:start position:0% +choice of the 1.6 billion which is paid + + + align:start position:0% +choice of the 1.6 billion which is paid +actually over 30 years or a lump sum + + align:start position:0% +actually over 30 years or a lump sum + + + align:start position:0% +actually over 30 years or a lump sum +they can get right away how should they + + align:start position:0% +they can get right away how should they + + + align:start position:0% +they can get right away how should they +decide which of those options to take + + align:start position:0% +decide which of those options to take + + + align:start position:0% +decide which of those options to take +how should I say I wouldn't think the + + align:start position:0% +how should I say I wouldn't think the + + + align:start position:0% +how should I say I wouldn't think the +1.6 billion paid over 30 years so in + + align:start position:0% +1.6 billion paid over 30 years so in + + + align:start position:0% +1.6 billion paid over 30 years so in +physics over 30 paid in equal + + align:start position:0% +physics over 30 paid in equal + + + align:start position:0% +physics over 30 paid in equal +installments you know over time versus + + align:start position:0% +installments you know over time versus + + + align:start position:0% +installments you know over time versus +just getting a lump sum today not if one + + align:start position:0% +just getting a lump sum today not if one + + + align:start position:0% +just getting a lump sum today not if one +put six million but a less at lower + + align:start position:0% +put six million but a less at lower + + + align:start position:0% +put six million but a less at lower +amount how should they think about that + + align:start position:0% + + + + align:start position:0% + +first value they should say well what do + + align:start position:0% +first value they should say well what do + + + align:start position:0% +first value they should say well what do +I think Peter's rates gonna be by this + + align:start position:0% +I think Peter's rates gonna be by this + + + align:start position:0% +I think Peter's rates gonna be by this +could be really low let's say the + + align:start position:0% +could be really low let's say the + + + align:start position:0% +could be really low let's say the +gate-source rates going to be zero then + + align:start position:0% +gate-source rates going to be zero then + + + align:start position:0% +gate-source rates going to be zero then +which deal should I take + + align:start position:0% + + + + align:start position:0% + +I should spread it out over time because + + align:start position:0% +I should spread it out over time because + + + align:start position:0% +I should spread it out over time because +the money and the futures worth the same + + align:start position:0% +the money and the futures worth the same + + + align:start position:0% +the money and the futures worth the same +is today so miles take the 1.6 billion + + align:start position:0% +is today so miles take the 1.6 billion + + + align:start position:0% +is today so miles take the 1.6 billion +but if I think since rates couldn't be + + align:start position:0% +but if I think since rates couldn't be + + + align:start position:0% +but if I think since rates couldn't be +higher then I should take the money + + align:start position:0% +higher then I should take the money + + + align:start position:0% +higher then I should take the money +upfront and invest that money and earn + + align:start position:0% +upfront and invest that money and earn + + + align:start position:0% +upfront and invest that money and earn +my own interest + + align:start position:0% +my own interest + + + align:start position:0% +my own interest +so essentially becomes a debate of how + + align:start position:0% +so essentially becomes a debate of how + + + align:start position:0% +so essentially becomes a debate of how +what you think the straight is versus + + align:start position:0% +what you think the straight is versus + + + align:start position:0% +what you think the straight is versus +what the state thinks interest rate is + + align:start position:0% +what the state thinks interest rate is + + + align:start position:0% +what the state thinks interest rate is +they're setting those two to be equal + + align:start position:0% +they're setting those two to be equal + + + align:start position:0% +they're setting those two to be equal +under some they're some assumption of + + align:start position:0% +under some they're some assumption of + + + align:start position:0% +under some they're some assumption of +the interest rate I don't know what + + align:start position:0% +the interest rate I don't know what + + + align:start position:0% +the interest rate I don't know what +number they chose whatever number they + + align:start position:0% +number they chose whatever number they + + + align:start position:0% +number they chose whatever number they +chose it was some number they chose + + align:start position:0% +chose it was some number they chose + + + align:start position:0% +chose it was some number they chose +because this is our assumption interest + + align:start position:0% +because this is our assumption interest + + + align:start position:0% +because this is our assumption interest +rate you've gotta decide do you think + + align:start position:0% +rate you've gotta decide do you think + + + align:start position:0% +rate you've gotta decide do you think +it's rates gonna be higher or lower + + align:start position:0% +it's rates gonna be higher or lower + + + align:start position:0% +it's rates gonna be higher or lower +these could be higher than the state + + align:start position:0% +these could be higher than the state + + + align:start position:0% +these could be higher than the state +thinks it is then you want the money up + + align:start position:0% +thinks it is then you want the money up + + + align:start position:0% +thinks it is then you want the money up +front and you'll invest it if you need + + align:start position:0% +front and you'll invest it if you need + + + align:start position:0% +front and you'll invest it if you need +to be lower than you should take your + + align:start position:0% +to be lower than you should take your + + + align:start position:0% +to be lower than you should take your +money over time + + align:start position:0% +money over time + + + align:start position:0% +money over time +and because the states giving you + + align:start position:0% +and because the states giving you + + + align:start position:0% +and because the states giving you +basically a better deal okay people + + align:start position:0% +basically a better deal okay people + + + align:start position:0% +basically a better deal okay people +understand that okay so now armed with + + align:start position:0% +understand that okay so now armed with + + + align:start position:0% +understand that okay so now armed with +this let's go and think about how do + + align:start position:0% +this let's go and think about how do + + + align:start position:0% +this let's go and think about how do +firms make investment decisions how do + + align:start position:0% +firms make investment decisions how do + + + align:start position:0% +firms make investment decisions how do +firms make investment decisions + + align:start position:0% + + + + align:start position:0% + +remember investment or investment is + + align:start position:0% +remember investment or investment is + + + align:start position:0% +remember investment or investment is +about the delay of future consumption of + + align:start position:0% +about the delay of future consumption of + + + align:start position:0% +about the delay of future consumption of +current consumption for future + + align:start position:0% +current consumption for future + + + align:start position:0% +current consumption for future +consumptions about putting some aside + + align:start position:0% +consumptions about putting some aside + + + align:start position:0% +consumptions about putting some aside +today by spending money on a machine + + align:start position:0% +today by spending money on a machine + + + align:start position:0% +today by spending money on a machine +which will deliver you benefits in the + + align:start position:0% +which will deliver you benefits in the + + + align:start position:0% +which will deliver you benefits in the +future now this adds one wrinkle to + + align:start position:0% +future now this adds one wrinkle to + + + align:start position:0% +future now this adds one wrinkle to +we've done so far which is that we've + + align:start position:0% +we've done so far which is that we've + + + align:start position:0% +we've done so far which is that we've +only talked about money that's always + + align:start position:0% +only talked about money that's always + + + align:start position:0% +only talked about money that's always +positive somehow you get in the future + + align:start position:0% +positive somehow you get in the future + + + align:start position:0% +positive somehow you get in the future +when you're making an investment + + align:start position:0% +when you're making an investment + + + align:start position:0% +when you're making an investment +decision it's a little bit more + + align:start position:0% +decision it's a little bit more + + + align:start position:0% +decision it's a little bit more +complicated because you're actually + + align:start position:0% +complicated because you're actually + + + align:start position:0% +complicated because you're actually +spending money today to make money + + align:start position:0% +spending money today to make money + + + align:start position:0% +spending money today to make money +tomorrow so in that case we talk about + + align:start position:0% +tomorrow so in that case we talk about + + + align:start position:0% +tomorrow so in that case we talk about +we call net present value which is the + + align:start position:0% +we call net present value which is the + + + align:start position:0% +we call net present value which is the +same thing it just allows for negative + + align:start position:0% +same thing it just allows for negative + + + align:start position:0% +same thing it just allows for negative +values net present value which is + + align:start position:0% +values net present value which is + + + align:start position:0% +values net present value which is +essentially saying in every period + + align:start position:0% +essentially saying in every period + + + align:start position:0% +essentially saying in every period +you want to count for the cost that + + align:start position:0% +you want to count for the cost that + + + align:start position:0% +you want to count for the cost that +period and the benefits that period and + + align:start position:0% +period and the benefits that period and + + + align:start position:0% +period and the benefits that period and +you want to invest only if the net + + align:start position:0% +you want to invest only if the net + + + align:start position:0% +you want to invest only if the net +present value is greater than zero so + + align:start position:0% +present value is greater than zero so + + + align:start position:0% +present value is greater than zero so +for example think about a project that + + align:start position:0% +for example think about a project that + + + align:start position:0% +for example think about a project that +has a stream of payments in every period + + align:start position:0% +has a stream of payments in every period + + + align:start position:0% +has a stream of payments in every period +of R sub I every period it's got stream + + align:start position:0% +of R sub I every period it's got stream + + + align:start position:0% +of R sub I every period it's got stream +of payments of R sub I and instead of + + align:start position:0% +of payments of R sub I and instead of + + + align:start position:0% +of payments of R sub I and instead of +costs of C sub I the costs are the + + align:start position:0% +costs of C sub I the costs are the + + + align:start position:0% +costs of C sub I the costs are the +upfront investment B the maintenance of + + align:start position:0% +upfront investment B the maintenance of + + + align:start position:0% +upfront investment B the maintenance of +the machine whatever it costs to run it + + align:start position:0% +the machine whatever it costs to run it + + + align:start position:0% +the machine whatever it costs to run it +okay then the net present value that + + align:start position:0% +okay then the net present value that + + + align:start position:0% +okay then the net present value that +investment + + align:start position:0% +investment + + + align:start position:0% +investment +is r0 minus C 0 comma r1 on a c1 over 1 + + align:start position:0% +is r0 minus C 0 comma r1 on a c1 over 1 + + + align:start position:0% +is r0 minus C 0 comma r1 on a c1 over 1 +plus I I'm sorry + + align:start position:0% +plus I I'm sorry + + + align:start position:0% +plus I I'm sorry +plus over 1 plus I plus r2 minus C 2 + + align:start position:0% +plus over 1 plus I plus r2 minus C 2 + + + align:start position:0% +plus over 1 plus I plus r2 minus C 2 +over 1 plus I squared plus 4 as many + + align:start position:0% +over 1 plus I squared plus 4 as many + + + align:start position:0% +over 1 plus I squared plus 4 as many +periods of the investment last okay + + align:start position:0% +periods of the investment last okay + + + align:start position:0% +periods of the investment last okay +that's the net present value of an + + align:start position:0% +that's the net present value of an + + + align:start position:0% +that's the net present value of an +investment so basically what you want to + + align:start position:0% +investment so basically what you want to + + + align:start position:0% +investment so basically what you want to +ask is take each parents costs and + + align:start position:0% +ask is take each parents costs and + + + align:start position:0% +ask is take each parents costs and +benefits into account on net is it + + align:start position:0% +benefits into account on net is it + + + align:start position:0% +benefits into account on net is it +greater than 0 okay so the key point is + + align:start position:0% +greater than 0 okay so the key point is + + + align:start position:0% +greater than 0 okay so the key point is +that basically sometimes investments + + align:start position:0% +that basically sometimes investments + + + align:start position:0% +that basically sometimes investments +which have upfront costs can be valuable + + align:start position:0% +which have upfront costs can be valuable + + + align:start position:0% +which have upfront costs can be valuable +as long as the long-run benefits are + + align:start position:0% +as long as the long-run benefits are + + + align:start position:0% +as long as the long-run benefits are +large enough so if you think about an + + align:start position:0% +large enough so if you think about an + + + align:start position:0% +large enough so if you think about an +investment that's got a hundred so so + + align:start position:0% +investment that's got a hundred so so + + + align:start position:0% +investment that's got a hundred so so +imagine think about a simple trivial + + align:start position:0% +imagine think about a simple trivial + + + align:start position:0% +imagine think about a simple trivial +example of the first period you buy a + + align:start position:0% +example of the first period you buy a + + + align:start position:0% +example of the first period you buy a +machine and it costs um and it cost $100 + + align:start position:0% +machine and it costs um and it cost $100 + + + align:start position:0% +machine and it costs um and it cost $100 +so c0 is 100 and let's say for every + + align:start position:0% +so c0 is 100 and let's say for every + + + align:start position:0% +so c0 is 100 and let's say for every +period thereafter that machine will + + align:start position:0% +period thereafter that machine will + + + align:start position:0% +period thereafter that machine will +deliver your revenues revenue i revenues + + align:start position:0% +deliver your revenues revenue i revenues + + + align:start position:0% +deliver your revenues revenue i revenues +for i greater than 0 of 200 but it will + + align:start position:0% +for i greater than 0 of 200 but it will + + + align:start position:0% +for i greater than 0 of 200 but it will +have maintenance costs costs i greater + + align:start position:0% +have maintenance costs costs i greater + + + align:start position:0% +have maintenance costs costs i greater +than 0 of 50 so what's the net present + + align:start position:0% +than 0 of 50 so what's the net present + + + align:start position:0% +than 0 of 50 so what's the net present +value well the net present value is + + align:start position:0% +value well the net present value is + + + align:start position:0% +value well the net present value is +simply minus 100 and let's say machine's + + align:start position:0% +simply minus 100 and let's say machine's + + + align:start position:0% +simply minus 100 and let's say machine's +gonna last forever + + align:start position:0% +gonna last forever + + + align:start position:0% +gonna last forever +minus 100 plus 150 over I think about + + align:start position:0% +minus 100 plus 150 over I think about + + + align:start position:0% +minus 100 plus 150 over I think about +that for a second basically what we're + + align:start position:0% +that for a second basically what we're + + + align:start position:0% +that for a second basically what we're +saying is you're throwing 100 out of + + align:start position:0% +saying is you're throwing 100 out of + + + align:start position:0% +saying is you're throwing 100 out of +today that's negative but every period + + align:start position:0% +today that's negative but every period + + + align:start position:0% +today that's negative but every period +your future going to net $150 because + + align:start position:0% +your future going to net $150 because + + + align:start position:0% +your future going to net $150 because +you're gonna make $250 maintenance cost + + align:start position:0% +you're gonna make $250 maintenance cost + + + align:start position:0% +you're gonna make $250 maintenance cost +and we have per formula so we just apply + + align:start position:0% +and we have per formula so we just apply + + + align:start position:0% +and we have per formula so we just apply +the formula for perpetuity we have a set + + align:start position:0% +the formula for perpetuity we have a set + + + align:start position:0% +the formula for perpetuity we have a set +of future payments of $150 so your net + + align:start position:0% +of future payments of $150 so your net + + + align:start position:0% +of future payments of $150 so your net +net present value is minus 100 plus 150 + + align:start position:0% +net present value is minus 100 plus 150 + + + align:start position:0% +net present value is minus 100 plus 150 +over I so let's think about + + align:start position:0% +over I so let's think about + + + align:start position:0% +over I so let's think about +look at this formula for a second what + + align:start position:0% +look at this formula for a second what + + + align:start position:0% +look at this formula for a second what +does that say what is the relationship + + align:start position:0% +does that say what is the relationship + + + align:start position:0% +does that say what is the relationship +between whether the firm's gonna want to + + align:start position:0% +between whether the firm's gonna want to + + + align:start position:0% +between whether the firm's gonna want to +invest and the interest rate what does + + align:start position:0% +invest and the interest rate what does + + + align:start position:0% +invest and the interest rate what does +this imply the relationship between + + align:start position:0% +this imply the relationship between + + + align:start position:0% +this imply the relationship between +firms desire for investment and the + + align:start position:0% +firms desire for investment and the + + + align:start position:0% +firms desire for investment and the +interest rate as the interest rate goes + + align:start position:0% +interest rate as the interest rate goes + + + align:start position:0% +interest rate as the interest rate goes +up + + align:start position:0% +up + + + align:start position:0% +up +well firms want to do more investment or + + align:start position:0% +well firms want to do more investment or + + + align:start position:0% +well firms want to do more investment or +less investment in Y well firms want to + + align:start position:0% +less investment in Y well firms want to + + + align:start position:0% +less investment in Y well firms want to +be more eager to buy machines or + + align:start position:0% +be more eager to buy machines or + + + align:start position:0% +be more eager to buy machines or +lessening to buy machines and why and + + align:start position:0% +lessening to buy machines and why and + + + align:start position:0% +lessening to buy machines and why and +straight goes up yeah let's see here + + align:start position:0% +straight goes up yeah let's see here + + + align:start position:0% +straight goes up yeah let's see here +less eager State again because why I + + align:start position:0% +less eager State again because why I + + + align:start position:0% +less eager State again because why I +think it easier thing is borrowing just + + align:start position:0% +think it easier thing is borrowing just + + + align:start position:0% +think it easier thing is borrowing just +think about they got a bunch of money + + align:start position:0% +think about they got a bunch of money + + + align:start position:0% +think about they got a bunch of money +Apple's got a bunch of money today + + align:start position:0% +Apple's got a bunch of money today + + + align:start position:0% +Apple's got a bunch of money today +they're sitting on if they buy the + + align:start position:0% +they're sitting on if they buy the + + + align:start position:0% +they're sitting on if they buy the +Machine they're going to get this return + + align:start position:0% +Machine they're going to get this return + + + align:start position:0% +Machine they're going to get this return +if they don't buy the Machine they can + + align:start position:0% +if they don't buy the Machine they can + + + align:start position:0% +if they don't buy the Machine they can +put it in the bank or invest in Apple + + align:start position:0% +put it in the bank or invest in Apple + + + align:start position:0% +put it in the bank or invest in Apple +stock and get some interest rate I the + + align:start position:0% +stock and get some interest rate I the + + + align:start position:0% +stock and get some interest rate I the +higher the alternative the higher the + + align:start position:0% +higher the alternative the higher the + + + align:start position:0% +higher the alternative the higher the +interest rate the less they want invest + + align:start position:0% +interest rate the less they want invest + + + align:start position:0% +interest rate the less they want invest +or think of it this way the interest + + align:start position:0% +or think of it this way the interest + + + align:start position:0% +or think of it this way the interest +rate is the opportunity cost of + + align:start position:0% +rate is the opportunity cost of + + + align:start position:0% +rate is the opportunity cost of +investment okay the more the firm + + align:start position:0% +investment okay the more the firm + + + align:start position:0% +investment okay the more the firm +invests in their machines the less they + + align:start position:0% +invests in their machines the less they + + + align:start position:0% +invests in their machines the less they +can earn saving through some other + + align:start position:0% +can earn saving through some other + + + align:start position:0% +can earn saving through some other +mechanism and the price that they pay by + + align:start position:0% +mechanism and the price that they pay by + + + align:start position:0% +mechanism and the price that they pay by +forgoing that other savings is I okay + + align:start position:0% +forgoing that other savings is I okay + + + align:start position:0% +forgoing that other savings is I okay +yeah basically you always want to try to + + align:start position:0% +yeah basically you always want to try to + + + align:start position:0% +yeah basically you always want to try to +make as much money as you can and make + + align:start position:0% +make as much money as you can and make + + + align:start position:0% +make as much money as you can and make +the cost as late as you can for any + + align:start position:0% +the cost as late as you can for any + + + align:start position:0% +the cost as late as you can for any +given amount you'd absolutely like to + + align:start position:0% +given amount you'd absolutely like to + + + align:start position:0% +given amount you'd absolutely like to +shift your you'd actually like + + align:start position:0% +shift your you'd actually like + + + align:start position:0% +shift your you'd actually like +absolutely like to do that + + align:start position:0% +absolutely like to do that + + + align:start position:0% +absolutely like to do that +that's why we'll talk about this in my + + align:start position:0% +that's why we'll talk about this in my + + + align:start position:0% +that's why we'll talk about this in my +in my public finance class we talked + + align:start position:0% +in my public finance class we talked + + + align:start position:0% +in my public finance class we talked +about why when you're paying taxes you + + align:start position:0% +about why when you're paying taxes you + + + align:start position:0% +about why when you're paying taxes you +always want to try to find shenanigans + + align:start position:0% +always want to try to find shenanigans + + + align:start position:0% +always want to try to find shenanigans +allow you to pay your taxes later so for + + align:start position:0% +allow you to pay your taxes later so for + + + align:start position:0% +allow you to pay your taxes later so for +any given tax until later you pay it the + + align:start position:0% +any given tax until later you pay it the + + + align:start position:0% +any given tax until later you pay it the +more cost the less it cost you because + + align:start position:0% +more cost the less it cost you because + + + align:start position:0% +more cost the less it cost you because +you get to earn the interest along the + + align:start position:0% +you get to earn the interest along the + + + align:start position:0% +you get to earn the interest along the +way and then pay it with after it and + + align:start position:0% +way and then pay it with after it and + + + align:start position:0% +way and then pay it with after it and +pay it later on this is a key + + align:start position:0% +pay it later on this is a key + + + align:start position:0% +pay it later on this is a key +macroeconomic concept you'll often hear + + align:start position:0% +macroeconomic concept you'll often hear + + + align:start position:0% +macroeconomic concept you'll often hear +in the news high interest rates are bad + + align:start position:0% +in the news high interest rates are bad + + + align:start position:0% +in the news high interest rates are bad +for business and you might have thought + + align:start position:0% +for business and you might have thought + + + align:start position:0% +for business and you might have thought +why is that this is why hunt rates are + + align:start position:0% +why is that this is why hunt rates are + + + align:start position:0% +why is that this is why hunt rates are +bad for the economy you'll hear why are + + align:start position:0% +bad for the economy you'll hear why are + + + align:start position:0% +bad for the economy you'll hear why are +high streets bad for the economy you + + align:start position:0% +high streets bad for the economy you + + + align:start position:0% +high streets bad for the economy you +might say wasted that makes no sense my + + align:start position:0% +might say wasted that makes no sense my + + + align:start position:0% +might say wasted that makes no sense my +interest rate means I earn more on my + + align:start position:0% +interest rate means I earn more on my + + + align:start position:0% +interest rate means I earn more on my +savings why is that bad for the economy + + align:start position:0% +savings why is that bad for the economy + + + align:start position:0% +savings why is that bad for the economy +it's bad for the economy because it + + align:start position:0% +it's bad for the economy because it + + + align:start position:0% +it's bad for the economy because it +lowers the demand for capital because + + align:start position:0% +lowers the demand for capital because + + + align:start position:0% +lowers the demand for capital because +the higher + + align:start position:0% +the higher + + + align:start position:0% +the higher +the interest rate the less firms + + align:start position:0% +the interest rate the less firms + + + align:start position:0% +the interest rate the less firms +actually want to invest the more they + + align:start position:0% +actually want to invest the more they + + + align:start position:0% +actually want to invest the more they +just want to stock their money away in + + align:start position:0% +just want to stock their money away in + + + align:start position:0% +just want to stock their money away in +the bank okay so that is kind of um + + align:start position:0% +the bank okay so that is kind of um + + + align:start position:0% +the bank okay so that is kind of um +that's the key that's the key question + + align:start position:0% +that's the key that's the key question + + + align:start position:0% +that's the key that's the key question +now then let me ask another question if + + align:start position:0% +now then let me ask another question if + + + align:start position:0% +now then let me ask another question if +you're a firm what's the right eye to + + align:start position:0% +you're a firm what's the right eye to + + + align:start position:0% +you're a firm what's the right eye to +use if you're a firm think about this + + align:start position:0% +use if you're a firm think about this + + + align:start position:0% +use if you're a firm think about this +investment we know the higher I is the + + align:start position:0% +investment we know the higher I is the + + + align:start position:0% +investment we know the higher I is the +less you want to invest but what is I + + align:start position:0% +less you want to invest but what is I + + + align:start position:0% +less you want to invest but what is I +once again forget inflation inflation + + align:start position:0% +once again forget inflation inflation + + + align:start position:0% +once again forget inflation inflation +zero what's the right what we call firm + + align:start position:0% +zero what's the right what we call firm + + + align:start position:0% +zero what's the right what we call firm +discount rate the discount rate is the + + align:start position:0% +discount rate the discount rate is the + + + align:start position:0% +discount rate the discount rate is the +amount by which firms are going to + + align:start position:0% +amount by which firms are going to + + + align:start position:0% +amount by which firms are going to +discount future dollars to bring them + + align:start position:0% +discount future dollars to bring them + + + align:start position:0% +discount future dollars to bring them +back today how does the firm think about + + align:start position:0% +back today how does the firm think about + + + align:start position:0% +back today how does the firm think about +what I to use what I should the firm use + + align:start position:0% + + + + align:start position:0% + +your Apple yeah they don't want invest + + align:start position:0% +your Apple yeah they don't want invest + + + align:start position:0% +your Apple yeah they don't want invest +unless it's positive that's a good point + + align:start position:0% +unless it's positive that's a good point + + + align:start position:0% +unless it's positive that's a good point +but but but but the way they do is they + + align:start position:0% +but but but but the way they do is they + + + align:start position:0% +but but but but the way they do is they +write down the method may plug in and I + + align:start position:0% +write down the method may plug in and I + + + align:start position:0% +write down the method may plug in and I +what I do they plug in yeah well I might + + align:start position:0% +what I do they plug in yeah well I might + + + align:start position:0% +what I do they plug in yeah well I might +be but it's not there's not one answer + + align:start position:0% +be but it's not there's not one answer + + + align:start position:0% +be but it's not there's not one answer +what's the general answer the firm wants + + align:start position:0% +what's the general answer the firm wants + + + align:start position:0% +what's the general answer the firm wants +to use what's the general answer that + + align:start position:0% +to use what's the general answer that + + + align:start position:0% +to use what's the general answer that +the firm if you're a firm thinking about + + align:start position:0% +the firm if you're a firm thinking about + + + align:start position:0% +the firm if you're a firm thinking about +in vacant investment you want to + + align:start position:0% +in vacant investment you want to + + + align:start position:0% +in vacant investment you want to +discount that investment what do you + + align:start position:0% +discount that investment what do you + + + align:start position:0% +discount that investment what do you +want to discount it by yeah the next + + align:start position:0% +want to discount it by yeah the next + + + align:start position:0% +want to discount it by yeah the next +best thing you could do so if I'm + + align:start position:0% +best thing you could do so if I'm + + + align:start position:0% +best thing you could do so if I'm +thinking about building this machine + + align:start position:0% +thinking about building this machine + + + align:start position:0% +thinking about building this machine +when I discount I wanna think about + + align:start position:0% +when I discount I wanna think about + + + align:start position:0% +when I discount I wanna think about +what's the next best thing I could do + + align:start position:0% +what's the next best thing I could do + + + align:start position:0% +what's the next best thing I could do +with that money + + align:start position:0% +with that money + + + align:start position:0% +with that money +that's the discount rate I want to use + + align:start position:0% +that's the discount rate I want to use + + + align:start position:0% +that's the discount rate I want to use +so in a world where firms either + + align:start position:0% +so in a world where firms either + + + align:start position:0% +so in a world where firms either +couldn't buy a machine or put it in the + + align:start position:0% +couldn't buy a machine or put it in the + + + align:start position:0% +couldn't buy a machine or put it in the +bank it's easy it's the bank interest + + align:start position:0% +bank it's easy it's the bank interest + + + align:start position:0% +bank it's easy it's the bank interest +rate but life's not that easy firms have + + align:start position:0% +rate but life's not that easy firms have + + + align:start position:0% +rate but life's not that easy firms have +dozens of investments so where every + + align:start position:0% +dozens of investments so where every + + + align:start position:0% +dozens of investments so where every +investment you want to discount it by + + align:start position:0% +investment you want to discount it by + + + align:start position:0% +investment you want to discount it by +the next best thing you can do with the + + align:start position:0% +the next best thing you can do with the + + + align:start position:0% +the next best thing you can do with the +money concept of opportunity cost that's + + align:start position:0% +money concept of opportunity cost that's + + + align:start position:0% +money concept of opportunity cost that's +why it's a very first thing we taught in + + align:start position:0% +why it's a very first thing we taught in + + + align:start position:0% +why it's a very first thing we taught in +this class opportunity cost is always + + align:start position:0% +this class opportunity cost is always + + + align:start position:0% +this class opportunity cost is always +what drives things okay questions about + + align:start position:0% +what drives things okay questions about + + + align:start position:0% +what drives things okay questions about +that now this isn't just for firms this + + align:start position:0% +that now this isn't just for firms this + + + align:start position:0% +that now this isn't just for firms this +same math applies to consumers as well + + align:start position:0% +same math applies to consumers as well + + + align:start position:0% +same math applies to consumers as well +let's think about me a number of years + + align:start position:0% +let's think about me a number of years + + + align:start position:0% +let's think about me a number of years +ago I had to decide whether to insulate + + align:start position:0% +ago I had to decide whether to insulate + + + align:start position:0% +ago I had to decide whether to insulate +my ancient house + + align:start position:0% +my ancient house + + + align:start position:0% +my ancient house +okay let's write down the numbers to + + align:start position:0% +okay let's write down the numbers to + + + align:start position:0% +okay let's write down the numbers to +sort of think how this worked + + align:start position:0% +sort of think how this worked + + + align:start position:0% +sort of think how this worked +I had heating bills at that time back + + align:start position:0% +I had heating bills at that time back + + + align:start position:0% +I had heating bills at that time back +when gas was cheaper of about two + + align:start position:0% +when gas was cheaper of about two + + + align:start position:0% +when gas was cheaper of about two +thousand dollars a year + + align:start position:0% +thousand dollars a year + + + align:start position:0% +thousand dollars a year +where's my heating bills for the house + + align:start position:0% +where's my heating bills for the house + + + align:start position:0% +where's my heating bills for the house +okay the best estimate I could get was + + align:start position:0% +okay the best estimate I could get was + + + align:start position:0% +okay the best estimate I could get was +it if I insulated my house I would lower + + align:start position:0% +it if I insulated my house I would lower + + + align:start position:0% +it if I insulated my house I would lower +my heating costs by 25% + + align:start position:0% +my heating costs by 25% + + + align:start position:0% +my heating costs by 25% +so my heating costs would fall by $500 + + align:start position:0% +so my heating costs would fall by $500 + + + align:start position:0% +so my heating costs would fall by $500 +per year if isolated my cost if isolated + + align:start position:0% +per year if isolated my cost if isolated + + + align:start position:0% +per year if isolated my cost if isolated +my house and the insulation but to + + align:start position:0% +my house and the insulation but to + + + align:start position:0% +my house and the insulation but to +inflate my house I had to pay the guy to + + align:start position:0% +inflate my house I had to pay the guy to + + + align:start position:0% +inflate my house I had to pay the guy to +insulate it and that cost the insulation + + align:start position:0% +insulate it and that cost the insulation + + + align:start position:0% +insulate it and that cost the insulation +cost $4,000 how do I think about whether + + align:start position:0% +cost $4,000 how do I think about whether + + + align:start position:0% +cost $4,000 how do I think about whether +they should insulate or not how do I + + align:start position:0% +they should insulate or not how do I + + + align:start position:0% +they should insulate or not how do I +think about that decision what equation + + align:start position:0% +think about that decision what equation + + + align:start position:0% +think about that decision what equation +should I write down yeah I should say + + align:start position:0% +should I write down yeah I should say + + + align:start position:0% +should I write down yeah I should say +I'll assume I'm gonna own the house + + align:start position:0% +I'll assume I'm gonna own the house + + + align:start position:0% +I'll assume I'm gonna own the house +forever or at least long enough that I + + align:start position:0% +forever or at least long enough that I + + + align:start position:0% +forever or at least long enough that I +can treat it as forever + + align:start position:0% +can treat it as forever + + + align:start position:0% +can treat it as forever +and I write down that formula and what + + align:start position:0% +and I write down that formula and what + + + align:start position:0% +and I write down that formula and what +that formula says is that if I think in + + align:start position:0% +that formula says is that if I think in + + + align:start position:0% +that formula says is that if I think in +shrinks less than 12.5% I should + + align:start position:0% +shrinks less than 12.5% I should + + + align:start position:0% +shrinks less than 12.5% I should +insulate if I think pH rate is more than + + align:start position:0% +insulate if I think pH rate is more than + + + align:start position:0% +insulate if I think pH rate is more than +12.5% I should just invest the money and + + align:start position:0% +12.5% I should just invest the money and + + + align:start position:0% +12.5% I should just invest the money and +use the use of returns that investment + + align:start position:0% +use the use of returns that investment + + + align:start position:0% +use the use of returns that investment +to pay my higher heating bills so it all + + align:start position:0% +to pay my higher heating bills so it all + + + align:start position:0% +to pay my higher heating bills so it all +depends on what the interest rate is + + align:start position:0% +depends on what the interest rate is + + + align:start position:0% +depends on what the interest rate is +okay now so that's why and I did it I + + align:start position:0% +okay now so that's why and I did it I + + + align:start position:0% +okay now so that's why and I did it I +insulated but that's exactly so the same + + align:start position:0% +insulated but that's exactly so the same + + + align:start position:0% +insulated but that's exactly so the same +logic we could think of is is basically + + align:start position:0% +logic we could think of is is basically + + + align:start position:0% +logic we could think of is is basically +essentially the same ideas firms you + + align:start position:0% +essentially the same ideas firms you + + + align:start position:0% +essentially the same ideas firms you +want think about the upfront costs and + + align:start position:0% +want think about the upfront costs and + + + align:start position:0% +want think about the upfront costs and +the long-run returns okay + + align:start position:0% +the long-run returns okay + + + align:start position:0% +the long-run returns okay +here's a funny economics question what + + align:start position:0% +here's a funny economics question what + + + align:start position:0% +here's a funny economics question what +if I don't intend to hold the house + + align:start position:0% +if I don't intend to hold the house + + + align:start position:0% +if I don't intend to hold the house +forever I would argue I should still use + + align:start position:0% +forever I would argue I should still use + + + align:start position:0% +forever I would argue I should still use +this formula why yeah + + align:start position:0% + + + + align:start position:0% + +exactly because I'm increasing the value + + align:start position:0% +exactly because I'm increasing the value + + + align:start position:0% +exactly because I'm increasing the value +of an asset that I'll then sell so + + align:start position:0% +of an asset that I'll then sell so + + + align:start position:0% +of an asset that I'll then sell so +presume by insulating I've raised the + + align:start position:0% +presume by insulating I've raised the + + + align:start position:0% +presume by insulating I've raised the +price of my house how much I raised it + + align:start position:0% +price of my house how much I raised it + + + align:start position:0% +price of my house how much I raised it +by exactly five hundred of her eyes so + + align:start position:0% +by exactly five hundred of her eyes so + + + align:start position:0% +by exactly five hundred of her eyes so +I'm gonna insulate and sell next year I + + align:start position:0% +I'm gonna insulate and sell next year I + + + align:start position:0% +I'm gonna insulate and sell next year I +should still insulate because I should + + align:start position:0% +should still insulate because I should + + + align:start position:0% +should still insulate because I should +get five hundred of RI more dollars for + + align:start position:0% +get five hundred of RI more dollars for + + + align:start position:0% +get five hundred of RI more dollars for +my house so in fact it doesn't matter if + + align:start position:0% +my house so in fact it doesn't matter if + + + align:start position:0% +my house so in fact it doesn't matter if +you can sell an asset then actually your + + align:start position:0% +you can sell an asset then actually your + + + align:start position:0% +you can sell an asset then actually your +pur isin is always infinite it's not + + align:start position:0% +pur isin is always infinite it's not + + + align:start position:0% +pur isin is always infinite it's not +just the short horizon which is kind of + + align:start position:0% +just the short horizon which is kind of + + + align:start position:0% +just the short horizon which is kind of +interesting insight okay so the last + + align:start position:0% +interesting insight okay so the last + + + align:start position:0% +interesting insight okay so the last +thing I want to talk about is the fact + + align:start position:0% +thing I want to talk about is the fact + + + align:start position:0% +thing I want to talk about is the fact +that these decisions are not just + + align:start position:0% +that these decisions are not just + + + align:start position:0% +that these decisions are not just +relevant you guys are like retirement + + align:start position:0% +relevant you guys are like retirement + + + align:start position:0% +relevant you guys are like retirement +business machines insulation guide your + + align:start position:0% +business machines insulation guide your + + + align:start position:0% +business machines insulation guide your +old John I don't care about any of this + + align:start position:0% +old John I don't care about any of this + + + align:start position:0% +old John I don't care about any of this +stuff well let's hear what something you + + align:start position:0% +stuff well let's hear what something you + + + align:start position:0% +stuff well let's hear what something you +care about which is going to college + + align:start position:0% +care about which is going to college + + + align:start position:0% +care about which is going to college +let's talk about your decision you've + + align:start position:0% +let's talk about your decision you've + + + align:start position:0% +let's talk about your decision you've +already made it but you've got a little + + align:start position:0% +already made it but you've got a little + + + align:start position:0% +already made it but you've got a little +sibling and they're deciding whether to + + align:start position:0% +sibling and they're deciding whether to + + + align:start position:0% +sibling and they're deciding whether to +go to college + + align:start position:0% +go to college + + + align:start position:0% +go to college +okay well let's and and and they're not + + align:start position:0% +okay well let's and and and they're not + + + align:start position:0% +okay well let's and and and they're not +going to go to MIT they're gonna go to a + + align:start position:0% +going to go to MIT they're gonna go to a + + + align:start position:0% +going to go to MIT they're gonna go to a +more typical school and they've got to + + align:start position:0% +more typical school and they've got to + + + align:start position:0% +more typical school and they've got to +decide whether go to college well in + + align:start position:0% +decide whether go to college well in + + + align:start position:0% +decide whether go to college well in +fact their decision is an investment + + align:start position:0% +fact their decision is an investment + + + align:start position:0% +fact their decision is an investment +decision just like any other investment + + align:start position:0% +decision just like any other investment + + + align:start position:0% +decision just like any other investment +decision what they're investing in is + + align:start position:0% +decision what they're investing in is + + + align:start position:0% +decision what they're investing in is +what we call their human capital when + + align:start position:0% +what we call their human capital when + + + align:start position:0% +what we call their human capital when +you get education you're investing in + + align:start position:0% +you get education you're investing in + + + align:start position:0% +you get education you're investing in +yourself just like you invest in a + + align:start position:0% +yourself just like you invest in a + + + align:start position:0% +yourself just like you invest in a +machine because you are you hope raising + + align:start position:0% +machine because you are you hope raising + + + align:start position:0% +machine because you are you hope raising +the value of what you can do of what you + + align:start position:0% +the value of what you can do of what you + + + align:start position:0% +the value of what you can do of what you +can earn by investing in learning stuff + + align:start position:0% +can earn by investing in learning stuff + + + align:start position:0% +can earn by investing in learning stuff +well that human capital investment has + + align:start position:0% +well that human capital investment has + + + align:start position:0% +well that human capital investment has +the same features of any other + + align:start position:0% +the same features of any other + + + align:start position:0% +the same features of any other +investment there's an opportunity cost + + align:start position:0% +investment there's an opportunity cost + + + align:start position:0% +investment there's an opportunity cost +which is what what's the opportunity + + align:start position:0% +which is what what's the opportunity + + + align:start position:0% +which is what what's the opportunity +cost of investing your time and going to + + align:start position:0% +cost of investing your time and going to + + + align:start position:0% +cost of investing your time and going to +come what's the opportunity cost of + + align:start position:0% +come what's the opportunity cost of + + + align:start position:0% +come what's the opportunity cost of +going to college yeah you could this to + + align:start position:0% +going to college yeah you could this to + + + align:start position:0% +going to college yeah you could this to +one is you can get a job you could not + + align:start position:0% +one is you can get a job you could not + + + align:start position:0% +one is you can get a job you could not +pay tuition so if you think about going + + align:start position:0% +pay tuition so if you think about going + + + align:start position:0% +pay tuition so if you think about going +to college you're sacrificing two things + + align:start position:0% +to college you're sacrificing two things + + + align:start position:0% +to college you're sacrificing two things +you all that money you're paying you + + align:start position:0% +you all that money you're paying you + + + align:start position:0% +you all that money you're paying you +could basically invest instead of giving + + align:start position:0% +could basically invest instead of giving + + + align:start position:0% +could basically invest instead of giving +it to some college and you can be a + + align:start position:0% +it to some college and you can be a + + + align:start position:0% +it to some college and you can be a +burning money instead of sitting here + + align:start position:0% +burning money instead of sitting here + + + align:start position:0% +burning money instead of sitting here +listening to me okay so if you think + + align:start position:0% +listening to me okay so if you think + + + align:start position:0% +listening to me okay so if you think +about that um you actually it actually + + align:start position:0% +about that um you actually it actually + + + align:start position:0% +about that um you actually it actually +becomes a hard decision you might think + + align:start position:0% +becomes a hard decision you might think + + + align:start position:0% +becomes a hard decision you might think +so let's think about a simple example + + align:start position:0% +so let's think about a simple example + + + align:start position:0% +so let's think about a simple example +let's imagine that if you don't go to + + align:start position:0% +let's imagine that if you don't go to + + + align:start position:0% +let's imagine that if you don't go to +you work from age 18 to 70 and if you do + + align:start position:0% +you work from age 18 to 70 and if you do + + + align:start position:0% +you work from age 18 to 70 and if you do +go to college work from age 22 to 70 + + align:start position:0% +go to college work from age 22 to 70 + + + align:start position:0% +go to college work from age 22 to 70 +sorry ignore grad school okay four years + + align:start position:0% +sorry ignore grad school okay four years + + + align:start position:0% +sorry ignore grad school okay four years +of college either start working in 18 + + align:start position:0% +of college either start working in 18 + + + align:start position:0% +of college either start working in 18 +and start working at 22 and let's say + + align:start position:0% +and start working at 22 and let's say + + + align:start position:0% +and start working at 22 and let's say +college cost $35,000 a year obviously + + align:start position:0% +college cost $35,000 a year obviously + + + align:start position:0% +college cost $35,000 a year obviously +not MIT okay let's say college cost + + align:start position:0% +not MIT okay let's say college cost + + + align:start position:0% +not MIT okay let's say college cost +$35,000 a year okay and let's say that + + align:start position:0% +$35,000 a year okay and let's say that + + + align:start position:0% +$35,000 a year okay and let's say that +if you worked + + align:start position:0% +if you worked + + + align:start position:0% +if you worked +you could have let's say that if you + + align:start position:0% +you could have let's say that if you + + + align:start position:0% +you could have let's say that if you +worked while you were if you worked + + align:start position:0% +worked while you were if you worked + + + align:start position:0% +worked while you were if you worked +starting in high school you could have + + align:start position:0% +starting in high school you could have + + + align:start position:0% +starting in high school you could have +earned + + align:start position:0% +earned + + + align:start position:0% +earned +um actually Patricia we don't have the + + align:start position:0% +um actually Patricia we don't have the + + + align:start position:0% +um actually Patricia we don't have the +yeah you could have earned $20,000 you + + align:start position:0% +yeah you could have earned $20,000 you + + + align:start position:0% +yeah you could have earned $20,000 you +could have earned $20,000 if you'd if + + align:start position:0% +could have earned $20,000 if you'd if + + + align:start position:0% +could have earned $20,000 if you'd if +you you could have started at $20,000 + + align:start position:0% +you you could have started at $20,000 + + + align:start position:0% +you you could have started at $20,000 +you've gone to work at age 18 okay well + + align:start position:0% +you've gone to work at age 18 okay well + + + align:start position:0% +you've gone to work at age 18 okay well +we can actually graph what this looks + + align:start position:0% +we can actually graph what this looks + + + align:start position:0% +we can actually graph what this looks +like in Figure 17 - 17 - if you think + + align:start position:0% +like in Figure 17 - 17 - if you think + + + align:start position:0% +like in Figure 17 - 17 - if you think +about age 18 from age 18 to age 22 + + align:start position:0% +about age 18 from age 18 to age 22 + + + align:start position:0% +about age 18 from age 18 to age 22 +that's the green area if you go to + + align:start position:0% +that's the green area if you go to + + + align:start position:0% +that's the green area if you go to +college you give up the $35,000 in + + align:start position:0% +college you give up the $35,000 in + + + align:start position:0% +college you give up the $35,000 in +tuition and the 20k you could have + + align:start position:0% +tuition and the 20k you could have + + + align:start position:0% +tuition and the 20k you could have +earned the bottom line is basically the + + align:start position:0% +earned the bottom line is basically the + + + align:start position:0% +earned the bottom line is basically the +red line is your lifetime earnings if + + align:start position:0% +red line is your lifetime earnings if + + + align:start position:0% +red line is your lifetime earnings if +you go to high school if you if you + + align:start position:0% +you go to high school if you if you + + + align:start position:0% +you go to high school if you if you +don't go to college the great the green + + align:start position:0% +don't go to college the great the green + + + align:start position:0% +don't go to college the great the green +line is your lifetime earnings the blue + + align:start position:0% +line is your lifetime earnings the blue + + + align:start position:0% +line is your lifetime earnings the blue +line I'm sorry is your lifetime earnings + + align:start position:0% +line I'm sorry is your lifetime earnings + + + align:start position:0% +line I'm sorry is your lifetime earnings +if you go to college empirical estimates + + align:start position:0% +if you go to college empirical estimates + + + align:start position:0% +if you go to college empirical estimates +suggests at age 22 the typical college + + align:start position:0% +suggests at age 22 the typical college + + + align:start position:0% +suggests at age 22 the typical college +graduate earns $45,000 yes you're not + + align:start position:0% +graduate earns $45,000 yes you're not + + + align:start position:0% +graduate earns $45,000 yes you're not +the typical college graduate the typical + + align:start position:0% +the typical college graduate the typical + + + align:start position:0% +the typical college graduate the typical +college graduates $45,000 and the + + align:start position:0% +college graduates $45,000 and the + + + align:start position:0% +college graduates $45,000 and the +typical highschool non-college educators + + align:start position:0% +typical highschool non-college educators + + + align:start position:0% +typical highschool non-college educators +are seven it's $28,000 so at age 22 you + + align:start position:0% +are seven it's $28,000 so at age 22 you + + + align:start position:0% +are seven it's $28,000 so at age 22 you +come out of college or any 45 and if + + align:start position:0% +come out of college or any 45 and if + + + align:start position:0% +come out of college or any 45 and if +you'd not gone to college we're in 28 + + align:start position:0% +you'd not gone to college we're in 28 + + + align:start position:0% +you'd not gone to college we're in 28 +not you but a normal person okay but + + align:start position:0% +not you but a normal person okay but + + + align:start position:0% +not you but a normal person okay but +moreover knowledge you learn more when + + align:start position:0% +moreover knowledge you learn more when + + + align:start position:0% +moreover knowledge you learn more when +you leave college your earnings grows + + align:start position:0% +you leave college your earnings grows + + + align:start position:0% +you leave college your earnings grows +faster so if you're college-educated not + + align:start position:0% +faster so if you're college-educated not + + + align:start position:0% +faster so if you're college-educated not +only means you earn 17 K more at 22 it + + align:start position:0% +only means you earn 17 K more at 22 it + + + align:start position:0% +only means you earn 17 K more at 22 it +also means your earnings grows faster so + + align:start position:0% +also means your earnings grows faster so + + + align:start position:0% +also means your earnings grows faster so +that by age 51 the + + align:start position:0% +that by age 51 the + + + align:start position:0% +that by age 51 the +average at college educated person earns + + align:start position:0% +average at college educated person earns + + + align:start position:0% +average at college educated person earns +$80,000 while the average high school + + align:start position:0% +$80,000 while the average high school + + + align:start position:0% +$80,000 while the average high school +person earns $45,000 so what you see + + align:start position:0% +person earns $45,000 so what you see + + + align:start position:0% +person earns $45,000 so what you see +here is the blue line starts above the + + align:start position:0% +here is the blue line starts above the + + + align:start position:0% +here is the blue line starts above the +red line okay and maybe I would learn to + + align:start position:0% +red line okay and maybe I would learn to + + + align:start position:0% +red line okay and maybe I would learn to +clip this on a fight and gone to college + + align:start position:0% +clip this on a fight and gone to college + + + align:start position:0% +clip this on a fight and gone to college +okay so the gap widens over time so how + + align:start position:0% +okay so the gap widens over time so how + + + align:start position:0% +okay so the gap widens over time so how +do we think about this decision well the + + align:start position:0% +do we think about this decision well the + + + align:start position:0% +do we think about this decision well the +cost is the green area the cost is over + + align:start position:0% +cost is the green area the cost is over + + + align:start position:0% +cost is the green area the cost is over +four years you could have earned money + + align:start position:0% +four years you could have earned money + + + align:start position:0% +four years you could have earned money +and you wouldn't had to pay tuition the + + align:start position:0% +and you wouldn't had to pay tuition the + + + align:start position:0% +and you wouldn't had to pay tuition the +benefit is the yellow area over that + + align:start position:0% +benefit is the yellow area over that + + + align:start position:0% +benefit is the yellow area over that +entire time after graduation you're + + align:start position:0% +entire time after graduation you're + + + align:start position:0% +entire time after graduation you're +making more money now obviously in terms + + align:start position:0% +making more money now obviously in terms + + + align:start position:0% +making more money now obviously in terms +of size the yellow area is much much + + align:start position:0% +of size the yellow area is much much + + + align:start position:0% +of size the yellow area is much much +bigger than the green area but the + + align:start position:0% +bigger than the green area but the + + + align:start position:0% +bigger than the green area but the +yellow area comes later that's the key + + align:start position:0% +yellow area comes later that's the key + + + align:start position:0% +yellow area comes later that's the key +thing she might look and say look it's + + align:start position:0% +thing she might look and say look it's + + + align:start position:0% +thing she might look and say look it's +obvious you get before this lecture you + + align:start position:0% +obvious you get before this lecture you + + + align:start position:0% +obvious you get before this lecture you +might say well it's obvious you go to + + align:start position:0% +might say well it's obvious you go to + + + align:start position:0% +might say well it's obvious you go to +college look the yellows way bigger than + + align:start position:0% +college look the yellows way bigger than + + + align:start position:0% +college look the yellows way bigger than +the green but that's not necessarily + + align:start position:0% +the green but that's not necessarily + + + align:start position:0% +the green but that's not necessarily +true cuz the green comes now and the + + align:start position:0% +true cuz the green comes now and the + + + align:start position:0% +true cuz the green comes now and the +yellow comes later indeed if you look at + + align:start position:0% +yellow comes later indeed if you look at + + + align:start position:0% +yellow comes later indeed if you look at +the table this actually shows the net + + align:start position:0% +the table this actually shows the net + + + align:start position:0% +the table this actually shows the net +present value on a college in high + + align:start position:0% +present value on a college in high + + + align:start position:0% +present value on a college in high +school and what this shows is at low + + align:start position:0% +school and what this shows is at low + + + align:start position:0% +school and what this shows is at low +interest rates you're much better off + + align:start position:0% +interest rates you're much better off + + + align:start position:0% +interest rates you're much better off +going to college so if there's no + + align:start position:0% +going to college so if there's no + + + align:start position:0% +going to college so if there's no +interest rate okay then college is a + + align:start position:0% +interest rate okay then college is a + + + align:start position:0% +interest rate okay then college is a +much much better deal your net present + + align:start position:0% +much much better deal your net present + + + align:start position:0% +much much better deal your net present +value of earnings if you go to you're + + align:start position:0% +value of earnings if you go to you're + + + align:start position:0% +value of earnings if you go to you're +never that I go to college is 2.6 + + align:start position:0% +never that I go to college is 2.6 + + + align:start position:0% +never that I go to college is 2.6 +million we're only 1.6 million if you + + align:start position:0% +million we're only 1.6 million if you + + + align:start position:0% +million we're only 1.6 million if you +don't go to college but once the + + align:start position:0% +don't go to college but once the + + + align:start position:0% +don't go to college but once the +interest rate gets above 8% it suddenly + + align:start position:0% +interest rate gets above 8% it suddenly + + + align:start position:0% +interest rate gets above 8% it suddenly +becomes a worse deal to go to college + + align:start position:0% +becomes a worse deal to go to college + + + align:start position:0% +becomes a worse deal to go to college +that is that only a 9% interest rate + + align:start position:0% +that is that only a 9% interest rate + + + align:start position:0% +that is that only a 9% interest rate +which existed not that long ago okay in + + align:start position:0% +which existed not that long ago okay in + + + align:start position:0% +which existed not that long ago okay in +our history it was actually a worse deal + + align:start position:0% +our history it was actually a worse deal + + + align:start position:0% +our history it was actually a worse deal +for to average person to go to college + + align:start position:0% +for to average person to go to college + + + align:start position:0% +for to average person to go to college +yeah well actually it's interesting it + + align:start position:0% +yeah well actually it's interesting it + + + align:start position:0% +yeah well actually it's interesting it +depends the poor financial aid why + + align:start position:0% +depends the poor financial aid why + + + align:start position:0% +depends the poor financial aid why +someone tell me why it's depend in the + + align:start position:0% +someone tell me why it's depend in the + + + align:start position:0% +someone tell me why it's depend in the +form of financial aid it actually comes + + align:start position:0% +form of financial aid it actually comes + + + align:start position:0% +form of financial aid it actually comes +in different forms so why is it depend + + align:start position:0% +in different forms so why is it depend + + + align:start position:0% +in different forms so why is it depend +on how you get the financial aid yeah if + + align:start position:0% +on how you get the financial aid yeah if + + + align:start position:0% +on how you get the financial aid yeah if +it's a life if it's a grant then yeah + + align:start position:0% +it's a life if it's a grant then yeah + + + align:start position:0% +it's a life if it's a grant then yeah +you should just take that out of the + + align:start position:0% +you should just take that out of the + + + align:start position:0% +you should just take that out of the +cost but if it's a loan depends what it + + align:start position:0% +cost but if it's a loan depends what it + + + align:start position:0% +cost but if it's a loan depends what it +straight you get the loan act if the low + + align:start position:0% +straight you get the loan act if the low + + + align:start position:0% +straight you get the loan act if the low +is that the market interest rate then + + align:start position:0% +is that the market interest rate then + + + align:start position:0% +is that the market interest rate then +it's no different right + + align:start position:0% +it's no different right + + + align:start position:0% +it's no different right +but that's a great point which is why + + align:start position:0% +but that's a great point which is why + + + align:start position:0% +but that's a great point which is why +college financial aid comes in two forms + + align:start position:0% +college financial aid comes in two forms + + + align:start position:0% +college financial aid comes in two forms +grants for very low income people and + + align:start position:0% +grants for very low income people and + + + align:start position:0% +grants for very low income people and +low-interest loans for other people why + + align:start position:0% +low-interest loans for other people why + + + align:start position:0% +low-interest loans for other people why +do we give loan which loans for college + + align:start position:0% +do we give loan which loans for college + + + align:start position:0% +do we give loan which loans for college +because of this graph because we're + + align:start position:0% +because of this graph because we're + + + align:start position:0% +because of this graph because we're +saying we want to we think people need + + align:start position:0% +saying we want to we think people need + + + align:start position:0% +saying we want to we think people need +to invest in their education we're + + align:start position:0% +to invest in their education we're + + + align:start position:0% +to invest in their education we're +afraid that if they face the regular + + align:start position:0% +afraid that if they face the regular + + + align:start position:0% +afraid that if they face the regular +interest rate they won't be willing to + + align:start position:0% +interest rate they won't be willing to + + + align:start position:0% +interest rate they won't be willing to +do it because the green that would + + align:start position:0% +do it because the green that would + + + align:start position:0% +do it because the green that would +bigger than the yellow so actually gonna + + align:start position:0% +bigger than the yellow so actually gonna + + + align:start position:0% +bigger than the yellow so actually gonna +subsidize their loan their interest rate + + align:start position:0% +subsidize their loan their interest rate + + + align:start position:0% +subsidize their loan their interest rate +so that's you might have thought to + + align:start position:0% +so that's you might have thought to + + + align:start position:0% +so that's you might have thought to +yourself sort of a weird way to get + + align:start position:0% +yourself sort of a weird way to get + + + align:start position:0% +yourself sort of a weird way to get +people to go to college is to have a + + align:start position:0% +people to go to college is to have a + + + align:start position:0% +people to go to college is to have a +lower student loan interest rate but in + + align:start position:0% +lower student loan interest rate but in + + + align:start position:0% +lower student loan interest rate but in +fact it makes perfect sense + + align:start position:0% +fact it makes perfect sense + + + align:start position:0% +fact it makes perfect sense +by having a student loan interest rate + + align:start position:0% +by having a student loan interest rate + + + align:start position:0% +by having a student loan interest rate +that's lower than the market rate you + + align:start position:0% +that's lower than the market rate you + + + align:start position:0% +that's lower than the market rate you +encourage people to go to college + + align:start position:0% +encourage people to go to college + + + align:start position:0% +encourage people to go to college +because essentially you lower this + + align:start position:0% +because essentially you lower this + + + align:start position:0% +because essentially you lower this +discount rate for at least at least on + + align:start position:0% +discount rate for at least at least on + + + align:start position:0% +discount rate for at least at least on +the part that's tuition payments okay so + + align:start position:0% +the part that's tuition payments okay so + + + align:start position:0% +the part that's tuition payments okay so +that's actually a very exciting um we + + align:start position:0% +that's actually a very exciting um we + + + align:start position:0% +that's actually a very exciting um we +need to think about in a very important + + align:start position:0% +need to think about in a very important + + + align:start position:0% +need to think about in a very important +part of public policy it's how we set + + align:start position:0% +part of public policy it's how we set + + + align:start position:0% +part of public policy it's how we set +the interest rate on student loans for + + align:start position:0% +the interest rate on student loans for + + + align:start position:0% +the interest rate on student loans for +any of you how many you guys have a + + align:start position:0% +any of you how many you guys have a + + + align:start position:0% +any of you how many you guys have a +student loan do you know and you gather + + align:start position:0% +student loan do you know and you gather + + + align:start position:0% +student loan do you know and you gather +student loan you might not know anyway I + + align:start position:0% +student loan you might not know anyway I + + + align:start position:0% +student loan you might not know anyway I +set the interest rate in that student + + align:start position:0% +set the interest rate in that student + + + align:start position:0% +set the interest rate in that student +loan so thank you actually when I was in + + align:start position:0% +loan so thank you actually when I was in + + + align:start position:0% +loan so thank you actually when I was in +the government I wasn't gone for + + align:start position:0% +the government I wasn't gone for + + + align:start position:0% +the government I wasn't gone for +fourteen months the Clinton + + align:start position:0% +fourteen months the Clinton + + + align:start position:0% +fourteen months the Clinton +administration it was super fun but + + align:start position:0% +administration it was super fun but + + + align:start position:0% +administration it was super fun but +looking back I only got one thing done + + align:start position:0% +looking back I only got one thing done + + + align:start position:0% +looking back I only got one thing done +which I got to set things straight in + + align:start position:0% +which I got to set things straight in + + + align:start position:0% +which I got to set things straight in +student loans so that was kind of fun uh + + align:start position:0% +student loans so that was kind of fun uh + + + align:start position:0% +student loans so that was kind of fun uh +but otherwise I it was just a lot of fun + + align:start position:0% +but otherwise I it was just a lot of fun + + + align:start position:0% +but otherwise I it was just a lot of fun +being there so so anyway uh let's stop + + align:start position:0% +being there so so anyway uh let's stop + + + align:start position:0% +being there so so anyway uh let's stop +there and we will we will continue uh + + align:start position:0% +there and we will we will continue uh + + + align:start position:0% +there and we will we will continue uh +let's say with it so no class on Monday + + align:start position:0% +let's say with it so no class on Monday + + + align:start position:0% +let's say with it so no class on Monday +that's Veterans Day so we'll meet in a + + align:start position:0% +that's Veterans Day so we'll meet in a + + + align:start position:0% +that's Veterans Day so we'll meet in a +week next Wednesday \ No newline at end of file diff --git a/BekDicq9MdM.txt b/BekDicq9MdM.txt new file mode 100644 index 0000000000000000000000000000000000000000..2b165e7b11607ed83a34ee67d44aac43d74a26e5 --- /dev/null +++ b/BekDicq9MdM.txt @@ -0,0 +1,3040 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high-quality educational +resources for free. + +To make a donation, or view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu. + +PROFESSOR: Ladies and gentlemen, +welcome to this + +lecture on nonlinear finite +element analysis of solids and + +structures. + +In this lecture, I like to +discuss with you solution + +methods that we use to solve the +finite element equations + +in nonlinear static analysis. + +In the previous lectures, we +derived this set of equations, + +where tK is a tangent +stiffness matrix. + +Delta Ui is a nodal point +vector of incremental + +displacements corresponding +to iteration i. + +t plus delta t R is the +externally applied load vector + +corresponding to time +t plus delta t. + +And t plus delta t F i minus 1 +is equal to the nodal point + +force vector corresponding to +the internal elements stresses + +at time t plus delta t, +and at the end of + +iteration i minus 1. + +The displacements are updated +as shown here. + +Delta Ui, of course, +is calculated + +from this set of equations. + +We add delta Ui to the previous +displacements that + +corresponded to iteration +t plus delta -- + +to time t plus delta t and +iteration i minus 1. + +It's the end of iteration +i minus 1. + +And this right-hand side gives +us the new displacement vector + +corresponding to iteration +i, end of iteration i. + +Now this is one scheme that it's +used to solve the finite + +element equations. + +We refer to this as +the mortified + +Newton-Raphson method. + +However, there are other +schemes as well. + +And schemes that are in certain + +problems much more effective. + +Since it is so important to use +an effective method for + +the solution of the finite +element equations because the + +costs can otherwise be very +high, we should be familiar + +with those other techniques. + +And I'd like to share +those now with you. + +Therefore, we will look in +this lecture at other + +techniques to solve the finite +element equations. + +And we need, of course, to +discuss convergence criteria. + +It's very important to use + +appropriate convergence criteria. + +Otherwise, you iterate too long +and/or on the other side, + +you may actually stop iterating +before you have + +achieved proper convergence. + +So let me then go over to my +view graphs and let us start + +the discussion here. + +The basic set of equations that +we would like to solve + +are given here. + +Notice R is the vector of +externally applied nodal point + +forces at time t plus delta t. + +And F is the vector of nodal +point forces corresponding to + +the internal element stresses +at time t plus delta t. + +Of course, this vector is +unknown, and we want to + +iterate somehow to find it and +make sure, of course, that at + +the end of that iteration, if we +have the proper vector F, R + +is equal to F, or R minus +F is equal to 0. + +We assume that the loading is +deformation-independent. + +If say, loading is +deformation-dependent, we can + +also deal with that situation. + +But we will have to add +additional terms to our + +iterative scheme. + +And I will get back to +that a little later. + +Notice that F in the total +Lagrangian formulation the way + +we have discussed it earlier is +evaluated by this product + +here integrated over the +original volume for a single + +element and for the UL +formulation, F is calculated + +as shown here. + +Here, of course, we integrate +over the current volume, or + +the volume that we actually +want to calculate. + +Notice in the iteration, of +course, this volume here would + +be t plus delta t V i minus 1 +as we will discuss just now. + +Because in the iteration, we +always update this integral + +and that integral with the +iteration counter that we are + +having on the right-hand side +of the system of equations. + +The methods that we use are +based on the Newton-Raphson + +method, which is really used +very abundantly to find roots + +of an equation. + +A small historical note: + +Newton gave a first version +of the method in 1669. + +Raphson then generalized and +simplified the method + +actually, in 1690. + +Both mathematicians used +the same concept. + +And both algorithms gave really, +the same results. + +But it is very appropriate to +refer to the methods that + +we're using as the +Newton-Raphson method because + +Raphson really contributed quite +a bit to that method. + +So let us now consider a single + +Newton-Raphson iteration. + +The way you may have actually +encountered it already earlier + +in your studies of solution +methods for the roots of an + +algebraic equation. + +Basically, what you're +doing is this. + +You're saying if you have xi +minus 1, you calculate + +f at xi minus 1. + +You divide this value by the +f prime at xi minus 1. + +And then this right-hand side +gives you better value, a + +better approximation to the +root of the equation. + +Once you have xi, you repeat +the process and + +you get xi plus 1. + +You keep on repeating the +process until, basically f xi + +here is close to 0. + +Because then you have a root. + +Well, if we use that +Newton-Raphson formula, it is + +quite interesting to see how +it has been derived. + +We can write for any point xi, +a neighboring point xi minus + +1, directly this equation here +by a Taylor series expansion. + +And if we neglect the higher +order terms, we get that f of + +xi is approximately equal to +this relationship on the + +right-hand side. + +Well, since f of xi is supposed +to be 0, because we + +are looking for a 0 of +the equation, we + +set it equal to 0. + +And here you see directly +the formula that + +I showed you earlier. + +So this is a very quick +derivation of the + +Newton-Raphson procedure. + +Let us look at a mathematical +example to see how the method + +works, and to get some insight +into the technique. + +Let us choose a very simple +example, not much to do with + +finite element analysis. + +Let us say that f of x equals +sine x and that our starting + +value is equal to 2 +for the iteration. + +You always have to choose, of +course, a starting value for + +the iteration. + +Then, in this column you see the +values that are calculated + +in the successive iterations. + +And we also show +here the error. + +It is interesting to observe +that when you are close to the + +root, you have quadratic +convergence. + +Meaning that the error here, +epsilon becomes an error. + +Epsilon squared here. + +This is summarized on +this view graph. + +Mathematically, if we have that +the error, Ei minus 1, is + +given by this equation here. + +Of course, there's an +approximate sign here. + +Then the error in the +next iteration + +will be of this order. + +So the convergence is really +very rapid once we are close + +to the root. + +Here we can see, however, +that if we are not + +close to the root-- + +in other words, if we are too +far from the root, and we pick + +a bad value, then we don't +get to the desired + +root, which is pi. + +But we get a value that +is far away from pi. + +It is also root, but certainly +not the root that we are + +interested in. + +So Newton-Raphson iteration +is not always convergent + +directly, converging directly +to the result that we would + +like to obtain. + +There has to be some care when +we use that iterative scheme. + +And in fact, we have to be close +enough just to basically + +say what has to happen. + +We have to be close enough to +the root in order to have + +convergence to the root that +we're looking for. + +And ultimately, if we do +converge to that root, we will + +get quadratic convergence +to the root. + +And that is, of course, +very desirable. + +But the starting value is +critical, as you can see here + +from this view graph. + +Let us look pictorially at +the solution process. + +Here we have our +sine function. + +And we are looking +for this root. + +In iteration 1, we basically set +up a tangent to that sine + +function at the starting +value, x0. + +And we calculate x1 using this +tangent as another estimate to + +the value that we're +interested in. + +Now in the iteration 2, we lay +a tangent to the f function. + +Which, of course, is sine +x, at the new value + +corresponding to x1. + +And with this tangent, +we get to this value. + +And you can see already +that we got closer + +to the desired value. + +We were this far away +originally. + +Then that far away. + +And now we are only +that far away. + +Notice our sine function +has this value here. + +And certainly, it's not 0 yet. + +So we lay another tangent +at that point. + +And that's being done on +this view graph here. + +Another tangent, and now +we get much closer + +to the desired value. + +Right here, x3 is already +quite close. + +But not close enough as +shown by this value. + +It's not yet close enough +to 0, this length here. + +And we lay another tangent +to that point now. + +And that's shown on this +view graph now. + +And we can see with the blue +line being the tangent at this + +point, we get x4 very close +to the 0 value that we are + +actually interested in. + +Certainly on this view graph, +you can't see any difference + +anymore between x4 and +the desired value. + +So this is basically the process +that we are following + +through when we go from +iteration 1 to iteration 2 to + +iteration 3 and to +iteration 4. + +Beautiful convergence in this +particular example. + +And the reason being that x0 is +close enough to the desired + +value, the desired root. + +Which, itself, of course, +is close to x4. + +Four + +Well, if however, we were to +take a value that is not close + +enough and then we, as I showed +earlier, we do not + +converge to the actual root. + +And this is shown here. + +For example, if we take a +tangent at a point where f of + +prime is almost 0, then of +course, this tangent throws us + +far away from this root. + +And we will converge +to some other root. + +Of course, we don't want to use +an exact 0 here because we + +have f of x divided +by f prime of x. + +So with an exact 0, we could +not [UNINTELLIGIBLE]. + +But a tangent that is close to +0, an f prime value that is + +close to 0, would throw us far +away from the desired root. + +And that shows some of the +difficulties using-- + +in fact, almost all iterative +schemes that we may not get + +fast enough to our root. + +And in fact, we may never get +to the root that we are + +looking for. + +Well, let us then look at the +Newton-Raphson iteration for + +multiple degrees of freedom. + +Here we have our R minus +F that we want to + +be setting to 0. + +Or we want to rather, solve for +the displacements t plus + +delta t U, which are the +solution because this t plus + +delta t u displacements would +give us this force vector. + +And this force vector +equilibrates the R vector. + +Meaning f of U, this little +f of U, is equal to 0. + +And that, of course, is what +we want to achieve. + +Notice that we have here, +of course, now + +n degrees of freedom. + +Therefore, n equations +to solve. + +Previously, we only looked +at one equation. + +If we apply the same principle +as before to this little f, + +namely we expand f as a Taylor +series about t plus delta t U + +i minus 1, then we get +this equation on + +the right-hand side. + +And of course, on the left-hand +side, we have f of t + +plus delta t Ui. + +Notice they are higher terms, +which we will neglect just as + +we have done earlier for +the single equation. + +Because we are looking for +Taylor series expansion about + +t plus delta t U i minus 1. + +If we neglect this part here, +we obtain directly this + +equation here. + +0 on the left-hand side, because +once again, we are + +looking for the displacements +values for which f is 0. + +So therefore, we set this +deliberately equal to 0. + +And on the right-hand side, we +have f t plus delta t U i + +minus 1 plus partial f with +respect to U times the delta + +U. This delta U is unknown, +of course, + +that we want to calculate. + +And this delta U is nothing +else then the difference + +between the U value in iteration +i and the U value in + +iteration i minus 1. + +Notice that this f is +evaluated at t plus + +delta t U i minus 1. + +Let us look now at +this equation. + +And if we write it a little bit +more out, we find that on + +the left-hand side, we have, +of course, a vector of 0's. + +On the right-hand side, we +have a vector of f i + +components, f1 to fn. + +All of which are evaluated at +t plus delta t U i minus 1. + +And then we have here a matrix, +which is a square + +matrix in which the individual +elements are partials of f i + +with respect to Uj. + +For example, f1, partial f1 +with respect to U1 here. + +Partial fn with respect to +U n here, et cetera. + +This matrix here will give us +a tangent stiffness matrix. + +Notice this matrix is multiplied +by the vector of + +incremental nodal point +displacements corresponding to + +iteration i. + +If we remember that f, the +little f, at t plus delta t U + +i minus 1 is equal to R minus +2 plus delta t F i minus 1. + +Capital F here, little +f there, remember? + +Then, the partial of little f +with respect to U at t plus + +delta t U i minus 1 is given +via this equation. + +Now, please recognize that +partial of R with respect to U + +is equal to 0 if the loads are +deformation-independent. + +Of course, if the loads depend +on the deformations, in other + +words, if the loads depend on +the U displacements, then this + +would not be 0, and we would +have to actually put a term in + +here, carry that term along +in the solution of + +the nonlinear equations. + +But for the moment, +we neglect this. + +We assume that the loads are +deformation-independent. + +And then, this term +is equal to 0. + +This here is now giving us the +tangent stiffness matrix. + +And it is written down here. + +The tangent stiffness matrix +is nothing else than the + +partials of capital F with +respect to the U's, to the + +displacements. + +The final result then is given +on this view graph. + +We substitute all the +information that I shared with + +you into the Taylor series +expansion around t plus delta + +t U i minus 1. + +We get directly this +equation here. + +Notice tangent stiffness matrix +corresponding to time t + +plus delta t and iteration +i minus 1. + +Delta U i corresponding to +iteration i we have to be very + +clear about this, that this is +an increment in displacement + +from time t plus delta t +iteration i minus 1 to + +iteration i. + +And of course, the nodal +point force vector. + +Externally applied nodal point +forces go in here. + +And this is the nodal point +force vector corresponding to + +the internal element stresses at +time t plus delta t and at + +the end of iteration +i minus 1. + +Evaluated differently in the +total Lagrangian formulation + +from the way we're evaluating +it in the updated Lagrangian + +formulation. + +We talked about this vector +abundantly in + +the previous lectures. + +We talked about this vector, +of course, also in the + +previous lectures. + +We had in the previous lectures +here at tK, a + +constant tangent stiffness +matrix, which was set up at + +the beginning of this whole +interactive process, and was + +never updated. + +Well, here we now update +that stiffness matrix. + +And I think if you look through +the information that I + +just discussed with you, +you recognize why + +we're updating it. + +We are doing so because we are +always starting with the new + +Taylor series expansion about +the point i minus 1. + +This set of equations if of +course solved for delta Ui. + +We add delta Ui to what we +had already in terms of + +displacements to get our new +estimate for the nodal point + +displacements. + +It is important to realize that +the K matrix, which we + +are using in the solution +process, is symmetric. + +Because first of all, we use +symmetric stress and strain + +measures in our governing +equation. + +Remember that when we apply the +principle of virtual work, + +we use Cauchy stresses +and infinitesimally + +small virtual strains. + +Now notice that both of these +tenses are symmetric tenses. + +Of course, these are the tenses +we're using in the UL, + +in the updated Lagrangian +formulation. + +In the total Lagrangian +formulation, we use the second + +Piola-Kirchhoff stress in +Green-Lagrange strain. + +Both of these measures are +again, symmetric measures. + +Both tenses are symmetric +tenses. + +If we had introduced for a +formulation non-symmetric + +tenses, for example a +non-symmetric stress tenser, + +and of course, an energy +conjugate non-symmetric strain + +tenser, we would have obtained +a non-symmetric K matrix, + +which would be much more +difficult to deal with. + +Much less cost effective in +the solution process. + +Also, please recognize that +we interpolated the real + +displacements and the virtual +displacements with exactly the + +same functions. + +Whereas this point here is a +continuum mechanics point, + +this is really a finite +element point. + +If we had used different +interpolation functions for + +the real displacements, then for +the virtual displacements, + +or vice-versa, then we would +have not necessarily obtained + +a symmetric K matrix. + +Of course, the most natural +procedure is to use the same + +kind of interpolation functions +for the virtual + +displacements as we used for +the real displacements, and + +that's what we did. + +Finally, we also assumed +that the loading was + +deformation-independent. + +If we have deformation-dependent +loading, + +then if you go more back to the +earlier view graph, then + +of course, this right-hand +side vector R here would + +depend on the displacements. + +And there are basically two +different approaches + +that one can take. + +In the first approach, one +simply updates this vector + +with the iteration, or with +taking into account the + +current or last calculated +volume and surface areas for + +the elements. + +So we would simply put here +an i minus 1 up there. + +The left-hand side matrix, +we leave unchanged. + +And if that converges fast, +certainly it's a very + +effective approach to use. + +We use that approach +abundantly. + +However, another approach +is to actually take the + +differentiation of R with +respect to the U's, the way we + +have been looking at it earlier +on an earlier view + +graph, and then you get some +components that you + +add to the K matrix. + +And that K matrix may then +out to be non-symmetric. + +However, if the loading is +deformation-independent, then + +the differentiation of R with +respect to the displacements U + +is equal to 0, and there's +no component from that + +differentiation coming +into the K matrix. + +And our K, of course, provided +these are also + +satisfied, is symmetric. + +The iterative scheme that we +just discussed is referred to + +as the full Newton-Raphson +method. + +Full because we are setting +up a new K matrix at the + +beginning of each iteration. + +The full Newton-Raphson method +shows mathematically quadratic + +convergence the way we discussed +it a bit earlier in + +the lecture. + +And that, of course, is always +the case provided you are + +close enough to the root. + +This quadratic convergence only +holds provided you are + +close enough to the root when +you solve your equations. + +In finite element analysis, it +is also important to recognize + +that a number of requirements +must be fulfilled. + +For example, in elasto-plastic +analysis, the stresses and + +strains must be properly-- + +plastic strains must be +properly updated. + +And similarly, the rotations +in a shell analysis must be + +properly updated. + +So it is not necessarily the +case that you automatically + +get quadratic convergence when +you do finite element + +announces with a full +Newton-Raphson method. + +It is very important to also, +on the level of updating the + +stresses and the rotations, +really do things properly in + +quotes in order to obtain the +full quadratic convergence of + +the Newton-Raphson method. + +We can depict the iteration +process in + +two equivalent ways. + +The first way is shown +here, the left. + +And it's really the way we've +been discussing just now the + +solution of f equals R minus +capital F. Where we want to + +solve for the root, the +0 of this equation. + +Notice here we have in red +the little f depicted. + +Notice that at this point here, +we have t plus delta t + +capital F i minus 1. + +And t plus delta t +R is this value. + +Now, as we get closer to the +root, which is of course, the + +point where the red curve +crosses this U-axis, as we get + +closer to the root, this capital +F will get closer and + +closer to the R. And that is, +of course, when the little f + +is equal to 0. + +That's all we are +showing here. + +Notice that we are setting up +a slope f prime at the point + +corresponding to the i minus +first iteration. + +And that slope brings us into +this point, which will be the + +next point for-- + +or the next starting point +for the next iteration. + +I should say, the point +of starting + +with the next iteration. + +Now, this is one way +of looking at + +the iterative process. + +We can also look at +it as shown here. + +Notice we have here the R +plotted now horizontally. + +The displacement vertically. + +Notice the R at a particular +time t plus delta t is shown + +by this dashed line. + +And we really want to find this +particular point here and + +the corresponding U displacement +of course. + +At this point, the little f is +0 and the corresponding U + +displacement is down here. + +Notice that at the iteration +i minus 1, it's the end of + +iteration i minus 1, we have +obtained this point here. + +The U displacement corresponding +to that point is + +obtained by projecting down +on the displacement axes. + +And this slope here, the blue +line, gives us a tangent + +stiffness matrix slope. + +These are two equivalent ways. + +This is here more like a force +deflection curve, and we will + +use this representation +now abundantly. + +But keep in mind, it's really +the same thing if you look at + +it closely. + +Well, modifications +to the iterative + +scheme are the following. + +If we leave the stiffness matrix +constant throughout a + +complete solution process-- + +in other words, tau is +equal to 0 here. + +It's never updated. + +We talk about the initial +stress method. + +If tau is equal to t, where t, +of course, corresponds to a + +particular solution step and +meaning that the K matrix is + +constant, but it is updated +as the beginning + +of a solution step. + +Then we talk about the modified +Newton method. + +Modified Newton-Raphson +method. + +Or, we may also find it +effective to update the K + +matrix only at particular +solution steps, at certain + +times only. + +We note that the initial stress +method and the modified + +Newton methods are, of course, +much less expensive than the + +full Newton method per +iteration, however. + +We should add that many more +iterations are necessary to + +achieve the same accuracy if we +don't set up a new K matrix + +in every iteration. + +The initial stress method and +modified Newton iteration + +technique do not exhibit +quadratic convergence because + +to obtain quadratic convergence, +you need to set + +up a new K matrix in +each iteration. + +And of course, you have to be +close enough to the root, to + +the solution that you're +looking for. + +Let us now look at +a simple example. + +An example where we have just +one degree of freedom. + +And where we deal with +two load steps. + +Here we show the force +applied to the + +problem, or to the structure. + +In the first load step, +we apply 1R. + +And then in the second +load step, 2R. + +Notice horizontally here, I'm +plotting displacements. + +And the force displacement +curve is + +shown by the red line. + +Now, to obtain the solution for +this displacement, U1, and + +that displacement U2, we, as +we discussed, set up a K + +matrix, which corresponds +to the slope, a + +slope on the red curve. + +And we iterate towards +the sought solutions. + +Here, we have the iterative +process using the initial + +stress method. + +In other words, where tau is +equal to 0 in our governing + +finite element equations. + +This means that we are setting +up a K matrix initially, and + +that K matrix is depicted here +by the slope, the blue slope + +that you're seeing. + +Now with this slope and this +load applied, we get the + +displacement shown down here. + +Notice the left superscript +means load step 1. + +The right superscript means +solution after iteration 1. + +And this is the solution +obtained from this triangle. + +Notice there's a blue line up +there, going up there, and + +where that blue line crosses the +dashed line, we pick up a + +vertical fine, black line. + +And that vertical black line +cuts through the displacement + +axes at this particular value. + +So this is the solution of +our first iteration. + +Now, having calculated this +displacement value, we go up + +vertically and get to the +red line, the red curve. + +And that red curve corresponds, +of course, to the + +internal forces. + +To the internal force I should +say, corresponding to this + +displacement. + +There's a red dot right +on that red curve. + +And at that red dot now, we've +set up a K matrix again. + +Now notice, in the initial +stress method, we keep the K + +matrix constant. + +This means that the slope here +of this blue line that goes + +through this red point is the +same as the slope that we had + +earlier right here. + +With that slope and the out of +balance load-- and let's look + +now very closely here-- + +that corresponds to the distance +between this red + +point and that dashed line with +this out of balance load + +and this blue slope, we get an +increment in displacement + +shown right here. + +And that increment in +displacement added to the + +previous displacement gives +us this value down here. + +And in fact, this value is +very close to the correct + +solution, the exact solution, +which is the solution + +corresponding to the dashed +vertical line here. + +Notice that the dashed vertical +line is the exact + +solution to that dashed +horizontal line. + +And our vertical black line, +which we are calculating, is + +virtually on that dashed +black line. + +So we can accept now, +convergence. + +Let's now go into the +next load step. + +In the next load step, +we want to, again, + +deal with a K matrix. + +And in the initial stress +method, we use the same K + +matrix throughout +the solution. + +Meaning that the slope now, +which we are laying onto the + +red curve, that slope being this +blue line, is the same + +slope that we used before in +the first two iterations. + +With this slope and the out of +balance load corresponding to + +the distance between this +horizontal line, the dashed + +horizontal line, and that dashed +horizontal line because + +we conversed in the +first load step. + +With that out of balance load, +we get an incremental + +displacement shown from +here to there. + +And that incremental +displacement then, added to + +the previous displacement, +gives us this value in + +displacement. + +Notice time t plus delta t or +load step t plus delta t, + +which is here. + +Load step 2 and iteration +1, end of iteration 1. + +This is now our current +displacement. + +With this current displacement, +once again, + +which comes from this triangle +here, with this current + +displacement, we go vertically +up and get to that red point, + +which lies on the force +displacement curve-- + +internal force displacement +curve more accurately. + +And now we have this red point, +and we set up, or we + +use now, again, a K matrix. + +Of course, in the initial +stress method we use the + +constant K matrix. + +So this slope is the +same as that slope. + +And now watch closely. + +From this triangle here, which +corresponds to this out of + +balance load, which is +the same as that + +out of balance load. + +Out of balance load obtained +by putting here + +a horizontal line. + +Notice and the difference +between the dashed line up + +there and the horizontal line +given by my pointer is the out + +of balance load. + +Which of course, is the same as +the distance between this + +red point and that +dashed line. + +This out of balance load with +this slope gives us another + +increment in displacement, +which brings us + +to this value here. + +We repeat that process and +iteratively, we get closer and + +closer to the correct solution, +the exact solution, + +which is the dashed vertical +line here for the + +displacement. + +Because at that dashed vertical +line, we are getting + +to that red curve. + +Now, this is the initial +stress method. + +And once again, the point here +is that we kept the same K + +matrix throughout the +solution process. + +Surely, if you now were to look +at this iterative scheme + +to obtain a faster solution, +you would want to + +set up a new K matrix. + +In other words, once you have +this displacement value + +calculated, you want to update +the slope corresponding to the + +slope of the red curve. + +And if you do so-- + +in other words, you update this +blue slope corresponding + +to the red dots that you +have obtained in + +your iterative scheme. + +These red dots, of course, +being different from what + +you're seeing here now. + +Then you would have the full +Newton-Raphson method. + +If you only update the K matrix +or the blue tangent + +that we are seeing here whenever +you have converged to + +an equilibrium point. + +Meaning when you have converged +corresponding for + +the first load step in +this particular case. + +If you only update the stiffness +matrix once you have + +converged to this load-- + +for this load step, then you +would have the modified + +Newton-Raphson method. + +I think if you look at this +picture with these + +possibilities, you will realize +that surely, the full + +Newton-Raphson method with +updating the slope after each + +iteration will converge +fastest. + +And the modified Newton-Raphson +method will + +converge a little slower than +the full Newton-Raphson + +method, but still faster than +the initial stress method. + +Well, this then brings us to the +end of the discussion of + +this example. + +I like to now introduce you to +another scheme that can be + +very important when we solve +nonlinear equations, finite + +element equations. + +And that scheme is the scheme +of line searches. + +The basic equations that we are +looking at that we want to + +solve are once more +depicted here. + +Tangent stiffness matrix, +incremental displacement + +vector, externally applied +loads, nodal point forces + +corresponding to the internal +element stresses at time t + +plus delta t, and at the end +of iteration i minus 1, + +beginning of iteration +i, of course. + +Notice I don't have an i on +here, I just want to denote + +this for the moment as an +incremental nodal point + +displacement vector, which +carries, however, a bar. + +Let us consider forming Fi using +this equation where beta + +is an unknown. + +We want to choose beta +now judiciously. + +We want to choose beta such +that, in some sense, R minus + +Fi is small. + +And we have to, of course, look +at the mechanism that we + +use to make R minus F +small in some sense. + +Well, as a side note, we +recognize that when this + +equation here is 0 for all +possible U's, then clearly + +this must be 0. + +In other words, if we were to +say to ourselves, let's make + +this equation 0 for +all possible U's. + +Then really, we would have +solved this equal to 0. + +The reason, of course, for it +is that we could choose here + +for U a vector, which carries +0's everywhere except a 1 in + +one location. + +And if that is a particular +row, then corresponding to + +that row, surely this vector +here, this R minus F + +corresponding to that row +must be equal to 0. + +So if we were simply to use here +the identity matrix, or + +if we were to construct the +identity matrix by allowing n + +U's that are linearly +independent, of course, + +because they all make up such +vector but with a 1 in a + +different location. + +As a matter of fact, we want to +use U1 with a 1 here, 0's + +everywhere. + +U2, 1 here, 0 here, everywhere +else 0, and so on. + +To construct an identity +matrix here. + +Then with that identity matrix, +clearly R minus F + +would be 0 everywhere. + +Of course, that is not a +viable scheme really. + +But what we want to do is to +choose a particular vector + +here so as to make R minus +F still 0 in some sense. + +And the vector that is quite +effectively chosen is the + +vector that we obtain from the +solution of K delta U bar + +equals R minus F. + +If we use that vector here, +basically projecting the R, + +capital R, minus F +onto that vector. + +And we look for this to be 0. + +Then we have so to say, searched +in the direction of + +delta U bar and made delta U +bar transposed times this + +vector here equal to 0. + +How does this scheme work? + +Well, we add beta times delta U +bar to the value that we had + +already from the previous +iteration. + +And we search along beta such +that this top here is much + +smaller than the bottom. + +In other words, STOL shall be +a convergence tolerance. + +Notice the way it works. + +We choose a value of beta. + +With beta known, we add this +quantity to this one. + +We get a value here. + +We take this value, calculate +Fi corresponding to that + +value, see whether +the convergence + +tolerance is satisfied. + +If not, we have to choose +a new beta. + +And like that, we choose new +betas until we have satisfied + +this convergence tolerance. + +That's what we call +line search. + +We are searching along the +line given by delta U bar + +until this is satisfied. + +It's a very important scheme, +and this scheme can be + +combined with modified Newton +iteration, with the initial + +stress method, and with +full Newton iteration. + +And it adds a lot to the +stability of the solution, of + +the overall solution or the +nonlinear equations. + +We will find, or discuss +applications just now. + +But at this point, we need to +stop for a minute because we + +need to go onto a new tape. + +Finally, I would like to discuss +with you a method that + +we also find to be very +effective in nonlinear finite + +element computations. + +Namely, the BFGS method. + +BFGS stands for Broyden-Fletcher + +-Goldfarb-Shanno. + +And in this method, we +proceed as follows. + +We calculate or define +a delta i as shown + +here in this equation. + +And we define a gamma i as +shown in this equation. + +We want to calculate the +coefficient matrix such that + +this equation is +here satisfied. + +In other words, given delta i +and gamma i, we want to use + +the coefficient matrix that +satisfies this equation. + +And that's basically what's +being done in the BFGS scheme. + +Pictorially then, we can show +for a single degree of freedom + +system, say the F plotted +along this axis. + +The U displacements plotted +along this axis. + +Notice here in green +we show delta i. + +And we show here in +green gamma i. + +And notice that the matrix +that we want to use is + +indicated by this blue slope. + +Which is, in other words, given +by delta i and gamma i. + +Well, the BFGS method is an +iterative algorithm, which + +produces successive +approximations to efficient + +stiffness matrix. + +Actually, we actually work +with the inverse of that + +stiffness matrix as I will +elaborate upon just now. + +It's really a compromise +between the full Newton + +iteration method and +the modified + +Newton iteration method. + +It shows very excellent +convergence characteristics in + +the solution of many +types of problems. + +Let's look at the individual +steps that we use when we + +apply the BFGS method. + +We, first of all, calculate +the direction of the + +displacement increment. + +Here we have delta U bar i is +equal to K inverse, the + +inverse of the K matrix, +corresponding to + +iteration i minus 1. + +And here we have the out +of balance load vector. + +Notice once again we do not +calculate actually an inverse + +of a matrix. + +We calculate the LDL transpose +factorization of a matrix, and + +then we, as I will just now +show, update that inverse in + +the BFGS iteration by specific +matrices of rank 2. + +We get to that just now. + +Well, having calculated this +delta U bar i, we use that + +delta U bar i in the line search +to obtain a better + +displacement vector, a +displacement vector + +corresponding to iteration i. + +A better value then just adding +the delta U bar i to it + +by adjusting beta. + +In other words, we choose beta +in such way as to satisfy this + +equation here. + +This is, of course, the equation +that we are now + +familiar with as being equation +that shows that + +convergence has been reached +in a line search. + +Having now calculated the t +plus delta t Ui and the + +corresponding t plus delta t Fi, +we can calculate the delta + +i and gamma i. + +And therefore, apply +the BFGS method. + +And that's now step three, +calculation of + +the new secant matrix. + +K inverse of iteration i is +equal to Ai transposed k + +inverse of iteration +i minus 1 times Ai. + +This A matrix is obtained +as shown here. + +v wi transposed. + +The vi and wi's are given as a +function of the delta i, gamma + +i, and K i minus 1 value. + +You should look at the textbook +to see the details of + +actually evaluating +the vi and wi. + +But once you have vi, wi, you +can calculate A. And clearly, + +by this equation then, you get +a new stiffness matrix. + +It is important to note that in +this iterative scheme, only + +vector products are needed +to obtain vi and wi. + +And it's also then important +to note that only vector + +products are used to calculate +delta U bar i. + +If this would not be the case, +particularly here. + +Then of course, the +iterative scheme + +would be very expensive. + +Let me show you a bit of the +details why we only need to + +use vector products to +get the solution. + +Here, we have one typical +step of the iteration. + +Notice on the left-hand side, +we have delta U bar i. + +The value of displacement +increment + +that we want to calculate. + +On the right-hand side, we +have i plus wi minus 1 vi + +minus 1 transposed. + +In other words, the Ai +minus 1 transposed. + +And we would have such matrices +going on here until + +we are coming to the A1 +transposed matrix. + +Then we have the inverse +of a stiffness matrix. + +Here, corresponding +to time tau. + +And then we have the Ai matrices +as shown here. + +Now, notice that this total +amount then is multiplied by + +the R minus F i minus 1, the +out of balance load vector. + +Let's now go through the +computations that are required + +to get delta U bar i. + +Here we have delta R. This delta +R, the out of balance + +load vector, which I +just call delta R, + +multiplies this matrix. + +But if you look at this +multiplication, we find that + +this delta R times w i minus 1 +transposed is simply a number. + +So it's one vector +multiplication + +that gives us a number. + +This number multiplied by +v i minus 1 is just the + +multiplication of a number +times a vector. + +It's very simple. + +And notice, of course, this +delta R i minus 1 is also + +multiplying the identity +matrix. + +So in this step here, we have +really nothing else then a + +vector multiplication. + +The only vector multiplication +that, in fact, is there, is + +this value, this vector here, +times that vector there, + +transposed. + +That gives us a number. + +This number times a vector +[UNINTELLIGIBLE] + +operation. + +And of course, this one here +times the i matrix is just + +this vector by itself. + +So in this step, what +we obtain is + +simply another vector. + +We take this vector and +repeat the process. + +And since the repetition is +just what we discussed + +already, we find that we only +need vector multiplications to + +roll up all of these +multiplications up to here. + +Then we have a vector multiplied +by K inverse. + +Well, that involves only vector +multiplications again, + +because we have already +the LDL transposed + +factorization of tau k. + +These vector multiplications +result again, in a vector. + +And that vector multiplied by +these matrices here in the + +same way as we have proceeded +here, means again, only vector + +multiplications. + +So this very important step +here only requires vector + +multiplications. + +And that makes this whole +process really efficient. + +In summary then, we have the +following solution procedures + +that we feel are +very effective. + +The mortified Newton-Raphson +iteration with line searches. + +Here we have the basic modified + +Newton iteration equation. + +And here we have the line +search equation. + +We, of course, after each such +solution, evaluate an + +efficient beta. + +A beta that makes U-- + +t plus delta U i a good vector +when measured on the line + +search criteria the way +I discussed it. + +And these two equations then, +summarize really the modified + +Newton iteration with +the line search. + +The BFGS method is another +effective scheme. + +We use the BFGS method always +with line searches. + +And then, as a third option, +the full Newton-Raphson + +iteration with or without +line searches. + +The full Newton-Raphson +iteration with line searches + +is, of course, most powerful. + +But it is also most expensive +per iteration. + +We should point out that these +techniques that I discussed so + +far cannot be applied for +post-buckling analysis. + +We will consider the solution of +the response after buckling + +has been occurring, after the +item load level has been + +reached in a forthcoming +lecture. + +The next view graphs summarize +these schemes: the modified + +Newton-Raphson, the BFGS +method, and the full + +Newton-Raphson method. + +And I'd like to just very +quickly go through the whole + +solution process for each +of these methods. + +In the modified Newton iteration +technique, we + +initialize our displacements +corresponding to the beginning + +of the first iteration, the end +of the 0 iteration as tU. + +And similarly, we initialize our +force vector corresponding + +to the internal element +stresses. + +We set i is equal to 1, the +iteration counter equal to 1. + +We calculate a K matrix at the +beginning of the load step, + +and we keep that K +matrix constant. + +We then go into this step here +where we calculate the out of + +balance loads. + +Calculate a new displacement +vector. + +And in this box here, we +measure whether we have + +converged already. + +Of course, this convergence +would only be measured after + +we have gone say, at +least twice through + +the iteration process. + +Or rather, we have calculated +this increment in displacement + +vector twice. + +Because at the beginning +corresponding to i equal to 1, + +we have now this fairly large +out of balance load. + +We have just incremented +the load vector. + +Therefore, this right inside +should be non-zero. + +And we would get an increment +in displacements. + +And to measure how large that +increment in displacement is, + +we really want to go through +this whole cycle at + +least one more time. + +We then, having calculated this +incremental displacement + +vector with the bar on there, +we perform a line search the + +way we discussed it to update +our displacements + +corresponding to the +iteration i. + +Of course, we only have come so +far once through it, so i + +is equal to 1 still. + +And this gives us the accepted +value of displacements + +corresponding to the +first iteration. + +We now increment our iteration +counter, and go in to the + +second iteration. + +Notice now in the second +iteration, we have R minus t + +plus delta t F1 here. + +We calculate delta U bar 2. + +And now we would certainly +measure convergence. + +And I will just now talk about +how we measure convergence. + +If we have not converged yet, +we keep on cycling through + +here until we do actually +get convergence. + +The distinguishing feature of +the modified Newton iteration + +is that we are having +a constant K matrix. + +That we do not update +the K matrix is this + +iterative loop here. + +It remains constant. + +Remember in the initial stress +technique, initial stress + +method, we would not even update +the K matrix ever after + +the first time it has +been calculated. + +But in the modified Newton +iteration, we update it at the + +beginning of each load step. + +In the BFGS method, we +proceed as follows. + +We initial, again, our +displacements and our nodal + +point force vector corresponding +to the internal + +element stresses. + +We calculate tK. + +We calculate our incremental +displacement vector with the + +bar on top. + +We measure convergence if i +is greater or equal to. + +There's no point as I just +mentioned, measuring + +convergence when you go first +time through here. + +And we perform then the line +search having calculated our + +actual incremental in nodal +point displacement that we + +want to add to the previous +nodal point displacements to + +get to this displacement +vector. + +We, of course, also have +this force vector. + +We now can update our inverse +matrix, our inverse secret + +matrix the way we +discussed it. + +And we increment our counter. + +And we keep on cycling through +here until we find in this box + +that we have converged. + +In the full Newton iteration +with line searches, we once + +again, initialize our +displacement vector, our force + +vector, our iteration counter. + +We now calculate a new K matrix +corresponding to the + +last conditions on displacements +and internal + +forces, of course. + +We enter here to calculate our +incremental displacement + +vector with the K matrix that +was just evaluated. + +And we measure convergence +once again only when i is + +greater equal to. + +We perform a line search to +determine beta in here. + +We therefore, update our +displacement vector to the + +displacements that now +correspond to the end of + +iteration i. + +We update our iteration +counter. + +Or rather, increase our +iteration counter. + +And we are calculating a new +stiffness matrix corresponding + +to the last calculated +displacement. + +This is, of course, a +distinguishing feature of the + +full Newton-Raphson method that +we are calculating a new + +K matrix at the beginning +of each iteration. + +Well, these view graphs then, +summarize the full process of + +iteration for the modified +Newton, the BFGS, and the full + +Newton method. + +Notice that I have included the +line search as the option. + +If you don't have line +searching, of course, it would + +simply mean that you set beta +equal to 1, and skip that + +particular step of +line searching. + +But in many cases, line +searching is quite important. + +And certainly, can +be necessary in + +some types of problems. + +Let us now look at what happens +in this box here. + +How do we measure convergence? + +In each of these iterative +schemes, we had such a box. + +And I like to look now more +closely at how we measure + +convergence. + +The measure of convergence +should, of course, tell us, + +how well do we satisfy +equilibrium? + +And there are basically three +items that can be used. + +Namely energy, force, or moment, +displacement, and + +rotation, of course, +correspondingly as well. + +But these are the items that one +can work with to measure + +convergence. + +If you use an energy convergence +criteria, and we + +are very fond of this one. + +You might want to use this +equation here delta U bar i + +transposed times the out of +balance load divided by delta + +U bar 1 transposed times t +plus delta t R minus tF. + +Now notice, this is the +increment in nodal point + +forces, or the out of +balance load, at the + +beginning of the load step. + +So this here is an energy +corresponding to the beginning + +of the load step. + +And we are comparing here +a similar quantity, but + +corresponding to the +current load. + +Corresponding to the +current iteration. + +And if this quotient here is +very small measured on that + +convergence tolerance, then +we say we have converged. + +An important point is that in +this convergence measure, we + +enter with displacements and +with out of balance loads. + +Both enter in this convergence +measure. + +And please realize also that +if the loads don't increase + +from time t to t plus delta t, +meaning that this here is + +equal to 0-- + +0 vector. + +Then, of course, we +get 0 down here. + +And we could not apply this +convergence criteria + +indirectly. + +Therefore, we would do is +instead of 0 here, a + +reasonable small number in +the computer program. + +Also note that we apply +this test here + +prior to line searching. + +In line searching, after line +searching of course, this top + +part here is small. + +And we, therefore, do not want +to apply this scheme here or + +this convergence measure +after line searching. + +We should do it before +line searching. + +To measure convergence on +forces, we can use this + +equation here. + +Notice here we have the +out of balance loads. + +We take the Euclidean norm on +the out of balance loads, and + +we compare that with +RNORM, input by the + +user, by the analyst. + +It is interesting, important to +note that we introduce here + +only the components +corresponding to the + +translational degrees +of freedom. + +And here, of course, this +RNORM is also a force + +corresponding, so to say, to a + +translational degree of freedom. + +If we have also rotational +degrees of freedom, then we + +would take instead +of RNORM, RMNORM. + +And we would extract from these +vectors, the components + +corresponding to the rotational + +degrees of freedom only. + +The point is that we want to +have the same units up + +here as down here. + +Forces, forces, moments, +moments. + +And we don't want to mix +components from these + +quantities. + +Of course, RMNORM and RNORM must +be chosen by the analyst. + +The are input to the analysis as +defined in the input to the + +computer program. + +Typically, RTOL is 0.01. + +RNORM is simply the maximum +of the NORM of the + +loads that are applied. + +Notice this Euclidean norm is +evaluated as shown down here + +for a vector a. + +The symbolism, two bars each +side with a 2 means nothing + +else then taking the squares of +all the components of the + +vector, adding those +squares up. + +And then, taking the square +root out of that addition. + +On displacements, we can also +measure convergence. + +And here is the equation +that can be used. + +The Euclidean norm on +the incremental + +displacement vector. + +And that is compared +with DNORM. + +Again, DNORM. + +Notice that this here is again, +input by the analyst to + +the computer program. + +It is part of the input that is +provided for the analysis. + +And it's a reference +displacement. + +Notice then, of course, we +should only include here the + +displacements, translational +displacements in other words. + +If we have also, rotational +degrees of freedom. + +Then we would here include only +the rotational degrees of + +freedom components and +use here DMNORM. + +This way again, we compare one +quantity with certain units + +with a quantity that +has the same units. + +Once for translations and +once for rotations. + +And so when we have rotational +degrees of freedom in the + +analysis, we this way make +sure really, that the + +incremental displacements and +incremental rotations are + +small at convergence. + +This then completes what I +wanted to share with you in + +this lecture. + +Thank you very much for +your attention. \ No newline at end of file diff --git a/CdrVM6MGnGo.txt b/CdrVM6MGnGo.txt new file mode 100644 index 0000000000000000000000000000000000000000..3bc656852a287f099d1580db2bcf81bfdd188f7f --- /dev/null +++ b/CdrVM6MGnGo.txt @@ -0,0 +1,779 @@ +align:start position:0% + +least mean squares estimation is + + align:start position:0% +least mean squares estimation is + + + align:start position:0% +least mean squares estimation is +remarkable because it has such a simple + + align:start position:0% +remarkable because it has such a simple + + + align:start position:0% +remarkable because it has such a simple +answer the way to come up with estimates + + align:start position:0% +answer the way to come up with estimates + + + align:start position:0% +answer the way to come up with estimates +if what you care about is to keep the + + align:start position:0% +if what you care about is to keep the + + + align:start position:0% +if what you care about is to keep the +mean squared error small the way to come + + align:start position:0% +mean squared error small the way to come + + + align:start position:0% +mean squared error small the way to come +up with estimates is to just report the + + align:start position:0% +up with estimates is to just report the + + + align:start position:0% +up with estimates is to just report the +conditional expectation which is going + + align:start position:0% +conditional expectation which is going + + + align:start position:0% +conditional expectation which is going +to be a number once you have obtained + + align:start position:0% +to be a number once you have obtained + + + align:start position:0% +to be a number once you have obtained +some values of the data or more + + align:start position:0% +some values of the data or more + + + align:start position:0% +some values of the data or more +abstractly you can think of it as a + + align:start position:0% +abstractly you can think of it as a + + + align:start position:0% +abstractly you can think of it as a +random variable if you do not know ahead + + align:start position:0% +random variable if you do not know ahead + + + align:start position:0% +random variable if you do not know ahead +of time what data you're going to obtain + + align:start position:0% +of time what data you're going to obtain + + + align:start position:0% +of time what data you're going to obtain +because this estimator is so important + + align:start position:0% +because this estimator is so important + + + align:start position:0% +because this estimator is so important +it is worth writing down what the + + align:start position:0% +it is worth writing down what the + + + align:start position:0% +it is worth writing down what the +performance of that estimator is so + + align:start position:0% +performance of that estimator is so + + + align:start position:0% +performance of that estimator is so +suppose that you have obtained a + + align:start position:0% +suppose that you have obtained a + + + align:start position:0% +suppose that you have obtained a +particular measurement a particular + + align:start position:0% +particular measurement a particular + + + align:start position:0% +particular measurement a particular +value of the observation then the + + align:start position:0% +value of the observation then the + + + align:start position:0% +value of the observation then the +resulting mean squared error within that + + align:start position:0% +resulting mean squared error within that + + + align:start position:0% +resulting mean squared error within that +conditional universe where you have + + align:start position:0% +conditional universe where you have + + + align:start position:0% +conditional universe where you have +already obtained that value is just this + + align:start position:0% +already obtained that value is just this + + + align:start position:0% +already obtained that value is just this +quantity it's the mean square of the + + align:start position:0% +quantity it's the mean square of the + + + align:start position:0% +quantity it's the mean square of the +error between the variable that you're + + align:start position:0% +error between the variable that you're + + + align:start position:0% +error between the variable that you're +trying to estimate and your estimate and + + align:start position:0% +trying to estimate and your estimate and + + + align:start position:0% +trying to estimate and your estimate and +everything gets computed within this + + align:start position:0% +everything gets computed within this + + + align:start position:0% +everything gets computed within this +conditional universe now this is a very + + align:start position:0% +conditional universe now this is a very + + + align:start position:0% +conditional universe now this is a very +familiar quantity however it's the + + align:start position:0% +familiar quantity however it's the + + + align:start position:0% +familiar quantity however it's the +expected value of a random variable + + align:start position:0% +expected value of a random variable + + + align:start position:0% +expected value of a random variable +difference from its mean squared this is + + align:start position:0% +difference from its mean squared this is + + + align:start position:0% +difference from its mean squared this is +just a variance except that because all + + align:start position:0% +just a variance except that because all + + + align:start position:0% +just a variance except that because all +quantities are calculated in a + + align:start position:0% +quantities are calculated in a + + + align:start position:0% +quantities are calculated in a +conditional universe this is the + + align:start position:0% +conditional universe this is the + + + align:start position:0% +conditional universe this is the +conditional variance so the conditional + + align:start position:0% +conditional variance so the conditional + + + align:start position:0% +conditional variance so the conditional +variance is the optimal mean squared + + align:start position:0% +variance is the optimal mean squared + + + align:start position:0% +variance is the optimal mean squared +error the mean squared error that you + + align:start position:0% +error the mean squared error that you + + + align:start position:0% +error the mean squared error that you +obtain when you use this particular + + align:start position:0% +obtain when you use this particular + + + align:start position:0% +obtain when you use this particular +estimate and it's the value that you + + align:start position:0% +estimate and it's the value that you + + + align:start position:0% +estimate and it's the value that you +would report to your boss if you were + + align:start position:0% +would report to your boss if you were + + + align:start position:0% +would report to your boss if you were +asked how good is the estimate that you + + align:start position:0% +asked how good is the estimate that you + + + align:start position:0% +asked how good is the estimate that you +are giving me but suppose that you have + + align:start position:0% +are giving me but suppose that you have + + + align:start position:0% +are giving me but suppose that you have +not yet obtained a measurement but you + + align:start position:0% +not yet obtained a measurement but you + + + align:start position:0% +not yet obtained a measurement but you +are going to your boss and you're + + align:start position:0% +are going to your boss and you're + + + align:start position:0% +are going to your boss and you're +proposing this particular estimator is + + align:start position:0% +proposing this particular estimator is + + + align:start position:0% +proposing this particular estimator is +your design what are you going to report + + align:start position:0% +your design what are you going to report + + + align:start position:0% +your design what are you going to report +to your boss is the performance of your + + align:start position:0% +to your boss is the performance of your + + + align:start position:0% +to your boss is the performance of your +design since you have not yet obtained + + align:start position:0% +design since you have not yet obtained + + + align:start position:0% +design since you have not yet obtained +the value of X X is the random variable + + align:start position:0% +the value of X X is the random variable + + + align:start position:0% +the value of X X is the random variable +you do not know what the value of this + + align:start position:0% +you do not know what the value of this + + + align:start position:0% +you do not know what the value of this +conditional expectation is going to be + + align:start position:0% +conditional expectation is going to be + + + align:start position:0% +conditional expectation is going to be +it's a random variable but no matter + + align:start position:0% +it's a random variable but no matter + + + align:start position:0% +it's a random variable but no matter +what it is this is going to be the error + + align:start position:0% +what it is this is going to be the error + + + align:start position:0% +what it is this is going to be the error +that you're going to be obtained + + align:start position:0% +that you're going to be obtained + + + align:start position:0% +that you're going to be obtained +and this is the overall value of the + + align:start position:0% +and this is the overall value of the + + + align:start position:0% +and this is the overall value of the +mean squared error so this is the + + align:start position:0% +mean squared error so this is the + + + align:start position:0% +mean squared error so this is the +quantity that you would report to your + + align:start position:0% +quantity that you would report to your + + + align:start position:0% +quantity that you would report to your +boss as your overall mean squared error + + align:start position:0% +boss as your overall mean squared error + + + align:start position:0% +boss as your overall mean squared error +the value that you report before + + align:start position:0% +the value that you report before + + + align:start position:0% +the value that you report before +obtaining any specific measurement now + + align:start position:0% +obtaining any specific measurement now + + + align:start position:0% +obtaining any specific measurement now +what is this quantity this quantity is + + align:start position:0% +what is this quantity this quantity is + + + align:start position:0% +what is this quantity this quantity is +just the average of this quantity up + + align:start position:0% +just the average of this quantity up + + + align:start position:0% +just the average of this quantity up +here averaged over all the possible + + align:start position:0% +here averaged over all the possible + + + align:start position:0% +here averaged over all the possible +values of X and in our more abstract + + align:start position:0% +values of X and in our more abstract + + + align:start position:0% +values of X and in our more abstract +notation it is just the expectation of + + align:start position:0% +notation it is just the expectation of + + + align:start position:0% +notation it is just the expectation of +the conditional variance the conditional + + align:start position:0% +the conditional variance the conditional + + + align:start position:0% +the conditional variance the conditional +variance the abstract conditional + + align:start position:0% +variance the abstract conditional + + + align:start position:0% +variance the abstract conditional +variance is a random variable that takes + + align:start position:0% +variance is a random variable that takes + + + align:start position:0% +variance is a random variable that takes +this value whenever capital X happens to + + align:start position:0% +this value whenever capital X happens to + + + align:start position:0% +this value whenever capital X happens to +be equal to little X and when we average + + align:start position:0% +be equal to little X and when we average + + + align:start position:0% +be equal to little X and when we average +it over all possible values of X we just + + align:start position:0% +it over all possible values of X we just + + + align:start position:0% +it over all possible values of X we just +have the expectation of this random + + align:start position:0% +have the expectation of this random + + + align:start position:0% +have the expectation of this random +variable let me continue now with a few + + align:start position:0% +variable let me continue now with a few + + + align:start position:0% +variable let me continue now with a few +more comments on LMS estimation first + + align:start position:0% +more comments on LMS estimation first + + + align:start position:0% +more comments on LMS estimation first +something that should be pretty clear at + + align:start position:0% +something that should be pretty clear at + + + align:start position:0% +something that should be pretty clear at +this point is that LMS estimation is + + align:start position:0% +this point is that LMS estimation is + + + align:start position:0% +this point is that LMS estimation is +only relevant to estimation problems + + align:start position:0% +only relevant to estimation problems + + + align:start position:0% +only relevant to estimation problems +this is because in hypothesis testing + + align:start position:0% +this is because in hypothesis testing + + + align:start position:0% +this is because in hypothesis testing +problems we typically care about the + + align:start position:0% +problems we typically care about the + + + align:start position:0% +problems we typically care about the +probability of error not the mean + + align:start position:0% +probability of error not the mean + + + align:start position:0% +probability of error not the mean +squared error a second important comment + + align:start position:0% +squared error a second important comment + + + align:start position:0% +squared error a second important comment +is that in some cases the LMS estimates + + align:start position:0% +is that in some cases the LMS estimates + + + align:start position:0% +is that in some cases the LMS estimates +and the map estimates turn out to be the + + align:start position:0% +and the map estimates turn out to be the + + + align:start position:0% +and the map estimates turn out to be the +same when is that the case if the + + align:start position:0% +same when is that the case if the + + + align:start position:0% +same when is that the case if the +posterior distribution of theta happens + + align:start position:0% +posterior distribution of theta happens + + + align:start position:0% +posterior distribution of theta happens +to have a single peak and it is also + + align:start position:0% +to have a single peak and it is also + + + align:start position:0% +to have a single peak and it is also +symmetric around a certain point so that + + align:start position:0% +symmetric around a certain point so that + + + align:start position:0% +symmetric around a certain point so that +the peak also occurs at that particular + + align:start position:0% +the peak also occurs at that particular + + + align:start position:0% +the peak also occurs at that particular +point then clearly the peak occurs here + + align:start position:0% +point then clearly the peak occurs here + + + align:start position:0% +point then clearly the peak occurs here +but the conditional expectation is also + + align:start position:0% +but the conditional expectation is also + + + align:start position:0% +but the conditional expectation is also +that same point because it is the center + + align:start position:0% +that same point because it is the center + + + align:start position:0% +that same point because it is the center +of symmetry so in those cases the two + + align:start position:0% +of symmetry so in those cases the two + + + align:start position:0% +of symmetry so in those cases the two +types of estimates or estimators + + align:start position:0% +types of estimates or estimators + + + align:start position:0% +types of estimates or estimators +coincide when does this happen + + align:start position:0% +coincide when does this happen + + + align:start position:0% +coincide when does this happen +this happens in one particular important + + align:start position:0% +this happens in one particular important + + + align:start position:0% +this happens in one particular important +special case we have seen that in linear + + align:start position:0% +special case we have seen that in linear + + + align:start position:0% +special case we have seen that in linear +normal models the posterior distribution + + align:start position:0% +normal models the posterior distribution + + + align:start position:0% +normal models the posterior distribution +is normal and so this is one + + align:start position:0% +is normal and so this is one + + + align:start position:0% +is normal and so this is one +is where the map estimate and the LMS + + align:start position:0% +is where the map estimate and the LMS + + + align:start position:0% +is where the map estimate and the LMS +estimates are going to coincide \ No newline at end of file diff --git a/DJO6ilwbWiI.txt b/DJO6ilwbWiI.txt new file mode 100644 index 0000000000000000000000000000000000000000..523f8d2d99fc86a5c05e885346ef5fcf3359cd03 --- /dev/null +++ b/DJO6ilwbWiI.txt @@ -0,0 +1,3475 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit mitop courseware at + + align:start position:0% +of MIT courses visit mitop courseware at + + + align:start position:0% +of MIT courses visit mitop courseware at +ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +hi in our lesson last time we showed + + align:start position:0% +hi in our lesson last time we showed + + + align:start position:0% +hi in our lesson last time we showed +that to find the general solution of a + + align:start position:0% +that to find the general solution of a + + + align:start position:0% +that to find the general solution of a +linear differential equation we first + + align:start position:0% +linear differential equation we first + + + align:start position:0% +linear differential equation we first +looked for the general solution of the + + align:start position:0% +looked for the general solution of the + + + align:start position:0% +looked for the general solution of the +homogeneous or reduced equation that is + + align:start position:0% +homogeneous or reduced equation that is + + + align:start position:0% +homogeneous or reduced equation that is +the equation where the right hand side + + align:start position:0% +the equation where the right hand side + + + align:start position:0% +the equation where the right hand side +was zero and then found a particular + + align:start position:0% +was zero and then found a particular + + + align:start position:0% +was zero and then found a particular +solution of the original equation and + + align:start position:0% +solution of the original equation and + + + align:start position:0% +solution of the original equation and +then the sum of these two solutions + + align:start position:0% +then the sum of these two solutions + + + align:start position:0% +then the sum of these two solutions +would be the general solution + + align:start position:0% +would be the general solution + + + align:start position:0% +would be the general solution +consequently we agreed that we would now + + align:start position:0% +consequently we agreed that we would now + + + align:start position:0% +consequently we agreed that we would now +separate our study into two parts one to + + align:start position:0% +separate our study into two parts one to + + + align:start position:0% +separate our study into two parts one to +find a general solution of the reduced + + align:start position:0% +find a general solution of the reduced + + + align:start position:0% +find a general solution of the reduced +or homogeneous equation and the other to + + align:start position:0% +or homogeneous equation and the other to + + + align:start position:0% +or homogeneous equation and the other to +find a particular solution of the given + + align:start position:0% +find a particular solution of the given + + + align:start position:0% +find a particular solution of the given +equation in today's lesson we are going + + align:start position:0% +equation in today's lesson we are going + + + align:start position:0% +equation in today's lesson we are going +to tackle the problem of finding the + + align:start position:0% +to tackle the problem of finding the + + + align:start position:0% +to tackle the problem of finding the +general solution of the homogeneous + + align:start position:0% +general solution of the homogeneous + + + align:start position:0% +general solution of the homogeneous +equation but subject to a very special + + align:start position:0% +equation but subject to a very special + + + align:start position:0% +equation but subject to a very special +case special in the sense that it's easy + + align:start position:0% +case special in the sense that it's easy + + + align:start position:0% +case special in the sense that it's easy +to handle but also special in the sense + + align:start position:0% +to handle but also special in the sense + + + align:start position:0% +to handle but also special in the sense +that many practical applications live up + + align:start position:0% +that many practical applications live up + + + align:start position:0% +that many practical applications live up +to this particular model what we're + + align:start position:0% +to this particular model what we're + + + align:start position:0% +to this particular model what we're +going to tackle today is solving the + + align:start position:0% +going to tackle today is solving the + + + align:start position:0% +going to tackle today is solving the +linear equation L of yal 0 subject to + + align:start position:0% +linear equation L of yal 0 subject to + + + align:start position:0% +linear equation L of yal 0 subject to +the condition that we have constant + + align:start position:0% +the condition that we have constant + + + align:start position:0% +the condition that we have constant +coefficients in other words we are going + + align:start position:0% +coefficients in other words we are going + + + align:start position:0% +coefficients in other words we are going +to deal with Y Prime + 2 a y Prime + b y + + align:start position:0% +to deal with Y Prime + 2 a y Prime + b y + + + align:start position:0% +to deal with Y Prime + 2 a y Prime + b y +equals z where A and B are constants the + + align:start position:0% +equals z where A and B are constants the + + + align:start position:0% +equals z where A and B are constants the +only reason I put the two in here is to + + align:start position:0% +only reason I put the two in here is to + + + align:start position:0% +only reason I put the two in here is to +simplify some algebra later on after all + + align:start position:0% +simplify some algebra later on after all + + + align:start position:0% +simplify some algebra later on after all +if a is an arbitrary constant so is 2 a + + align:start position:0% +if a is an arbitrary constant so is 2 a + + + align:start position:0% +if a is an arbitrary constant so is 2 a +we'll talk about that in more detail + + align:start position:0% +we'll talk about that in more detail + + + align:start position:0% +we'll talk about that in more detail +when where I need it the thing is that + + align:start position:0% +when where I need it the thing is that + + + align:start position:0% +when where I need it the thing is that +to solve an equation of this particular + + align:start position:0% +to solve an equation of this particular + + + align:start position:0% +to solve an equation of this particular +type where A and B are constants we + + align:start position:0% +type where A and B are constants we + + + align:start position:0% +type where A and B are constants we +essentially try for a solution in the + + align:start position:0% +essentially try for a solution in the + + + align:start position:0% +essentially try for a solution in the +form yal e to the RX recalling that when + + align:start position:0% +form yal e to the RX recalling that when + + + align:start position:0% +form yal e to the RX recalling that when +we differentiate this we get r e to the + + align:start position:0% +we differentiate this we get r e to the + + + align:start position:0% +we differentiate this we get r e to the +RX when we differentiate a second time + + align:start position:0% +RX when we differentiate a second time + + + align:start position:0% +RX when we differentiate a second time +we get R 2 e to the RX consequently + + align:start position:0% +we get R 2 e to the RX consequently + + + align:start position:0% +we get R 2 e to the RX consequently +substituting this into here we get that + + align:start position:0% +substituting this into here we get that + + + align:start position:0% +substituting this into here we get that +e to the RX is a constant factor and + + align:start position:0% +e to the RX is a constant factor and + + + align:start position:0% +e to the RX is a constant factor and +we're then left with a polinomial in r + + align:start position:0% +we're then left with a polinomial in r + + + align:start position:0% +we're then left with a polinomial in r +equal to r^ 2 + 2 a r + B in other words + + align:start position:0% +equal to r^ 2 + 2 a r + B in other words + + + align:start position:0% +equal to r^ 2 + 2 a r + B in other words +mechanically notice that the power of R + + align:start position:0% +mechanically notice that the power of R + + + align:start position:0% +mechanically notice that the power of R +replaces the given derivative R 2 + + align:start position:0% +replaces the given derivative R 2 + + + align:start position:0% +replaces the given derivative R 2 +replaces y Prime R to the first Power + + align:start position:0% +replaces y Prime R to the first Power + + + align:start position:0% +replaces y Prime R to the first Power +replaces y Prime and this is the r to + + align:start position:0% +replaces y Prime and this is the r to + + + align:start position:0% +replaces y Prime and this is the r to +the zero term replaces the zero + + align:start position:0% +the zero term replaces the zero + + + align:start position:0% +the zero term replaces the zero +derivative term namely the zeroth + + align:start position:0% +derivative term namely the zeroth + + + align:start position:0% +derivative term namely the zeroth +derivative is y itself at any rate since + + align:start position:0% +derivative is y itself at any rate since + + + align:start position:0% +derivative is y itself at any rate since +e to the RX cannot be zero to find the + + align:start position:0% +e to the RX cannot be zero to find the + + + align:start position:0% +e to the RX cannot be zero to find the +values of r that satisfy this equation + + align:start position:0% +values of r that satisfy this equation + + + align:start position:0% +values of r that satisfy this equation +then what we have to do is set this + + align:start position:0% +then what we have to do is set this + + + align:start position:0% +then what we have to do is set this +polinomial in this case a quadratic + + align:start position:0% +polinomial in this case a quadratic + + + align:start position:0% +polinomial in this case a quadratic +equation and notice of course if I had + + align:start position:0% +equation and notice of course if I had + + + align:start position:0% +equation and notice of course if I had +order greater than two the same Theory + + align:start position:0% +order greater than two the same Theory + + + align:start position:0% +order greater than two the same Theory +would hold I have simply as usual picked + + align:start position:0% +would hold I have simply as usual picked + + + align:start position:0% +would hold I have simply as usual picked +second order equations for illustrative + + align:start position:0% +second order equations for illustrative + + + align:start position:0% +second order equations for illustrative +purposes the exercises will take care of + + align:start position:0% +purposes the exercises will take care of + + + align:start position:0% +purposes the exercises will take care of +higher orders at any rate the values of + + align:start position:0% +higher orders at any rate the values of + + + align:start position:0% +higher orders at any rate the values of +R are determined by the equation r^2 + 2 + + align:start position:0% +R are determined by the equation r^2 + 2 + + + align:start position:0% +R are determined by the equation r^2 + 2 +a r + B = 0 now you see if I use the + + align:start position:0% +a r + B = 0 now you see if I use the + + + align:start position:0% +a r + B = 0 now you see if I use the +quadratic formula and solve this + + align:start position:0% +quadratic formula and solve this + + + align:start position:0% +quadratic formula and solve this +equation for r i find that R is minus a + + align:start position:0% +equation for r i find that R is minus a + + + align:start position:0% +equation for r i find that R is minus a +plus or minus the square < TK of a^2 + + align:start position:0% +plus or minus the square < TK of a^2 + + + align:start position:0% +plus or minus the square < TK of a^2 +minus B that's the reason I used 2 a + + align:start position:0% +minus B that's the reason I used 2 a + + + align:start position:0% +minus B that's the reason I used 2 a +instead of a here you see if I had used + + align:start position:0% +instead of a here you see if I had used + + + align:start position:0% +instead of a here you see if I had used +a here without the two then the + + align:start position:0% +a here without the two then the + + + align:start position:0% +a here without the two then the +quadratic formula would would have said + + align:start position:0% +quadratic formula would would have said + + + align:start position:0% +quadratic formula would would have said +R is equal to - A plus or minus the sare + + align:start position:0% +R is equal to - A plus or minus the sare + + + align:start position:0% +R is equal to - A plus or minus the sare +< TK of a^ 2 - 4 B over 2 a and with + + align:start position:0% +< TK of a^ 2 - 4 B over 2 a and with + + + align:start position:0% +< TK of a^ 2 - 4 B over 2 a and with +Blackboard space at a premium I hate to + + align:start position:0% +Blackboard space at a premium I hate to + + + align:start position:0% +Blackboard space at a premium I hate to +have to keep writing in a 2A as a + + align:start position:0% +have to keep writing in a 2A as a + + + align:start position:0% +have to keep writing in a 2A as a +denominator and every time I do that I + + align:start position:0% +denominator and every time I do that I + + + align:start position:0% +denominator and every time I do that I +lose a line of space on my board so for + + align:start position:0% +lose a line of space on my board so for + + + align:start position:0% +lose a line of space on my board so for +convenience sake I chose the two in here + + align:start position:0% +convenience sake I chose the two in here + + + align:start position:0% +convenience sake I chose the two in here +so I could write R this way now notice + + align:start position:0% +so I could write R this way now notice + + + align:start position:0% +so I could write R this way now notice +that in general this determines two + + align:start position:0% +that in general this determines two + + + align:start position:0% +that in general this determines two +values of r one with the positive square + + align:start position:0% +values of r one with the positive square + + + align:start position:0% +values of r one with the positive square +root one with the negative square root + + align:start position:0% +root one with the negative square root + + + align:start position:0% +root one with the negative square root +let me call R1 the root that I get with + + align:start position:0% +let me call R1 the root that I get with + + + align:start position:0% +let me call R1 the root that I get with +a positive sign R2 the root with a + + align:start position:0% +a positive sign R2 the root with a + + + align:start position:0% +a positive sign R2 the root with a +negative sign and the point that I want + + align:start position:0% +negative sign and the point that I want + + + align:start position:0% +negative sign and the point that I want +to mention is that the nature of the + + align:start position:0% +to mention is that the nature of the + + + align:start position:0% +to mention is that the nature of the +magnitude of a^2 minus B determines what + + align:start position:0% +magnitude of a^2 minus B determines what + + + align:start position:0% +magnitude of a^2 minus B determines what +the values of R look like for example if + + align:start position:0% +the values of R look like for example if + + + align:start position:0% +the values of R look like for example if +a^2 minus B is positive then R1 and R2 + + align:start position:0% +a^2 minus B is positive then R1 and R2 + + + align:start position:0% +a^2 minus B is positive then R1 and R2 +are unequal real Roots if A2 minus B if + + align:start position:0% +are unequal real Roots if A2 minus B if + + + align:start position:0% +are unequal real Roots if A2 minus B if +A2 minus B is zero then R1 and R2 are + + align:start position:0% +A2 minus B is zero then R1 and R2 are + + + align:start position:0% +A2 minus B is zero then R1 and R2 are +both equal toga a and if a^ 2 minus B is + + align:start position:0% +both equal toga a and if a^ 2 minus B is + + + align:start position:0% +both equal toga a and if a^ 2 minus B is +negative R1 and R2 are complex + + align:start position:0% +negative R1 and R2 are complex + + + align:start position:0% +negative R1 and R2 are complex +conjugates now the idea is simply this + + align:start position:0% +conjugates now the idea is simply this + + + align:start position:0% +conjugates now the idea is simply this +what we're going to do now is I'm going + + align:start position:0% +what we're going to do now is I'm going + + + align:start position:0% +what we're going to do now is I'm going +to summarize for you what these results + + align:start position:0% +to summarize for you what these results + + + align:start position:0% +to summarize for you what these results +are I'm going to use the cookbook + + align:start position:0% +are I'm going to use the cookbook + + + align:start position:0% +are I'm going to use the cookbook +technique first of illustrating all + + align:start position:0% +technique first of illustrating all + + + align:start position:0% +technique first of illustrating all +three cases for you giving you examples + + align:start position:0% +three cases for you giving you examples + + + align:start position:0% +three cases for you giving you examples +of each and then I will conclude today's + + align:start position:0% +of each and then I will conclude today's + + + align:start position:0% +of each and then I will conclude today's +lesson simply by showing you why the + + align:start position:0% +lesson simply by showing you why the + + + align:start position:0% +lesson simply by showing you why the +recipes work and with a little bit of + + align:start position:0% +recipes work and with a little bit of + + + align:start position:0% +recipes work and with a little bit of +luck for the first time in our course we + + align:start position:0% +luck for the first time in our course we + + + align:start position:0% +luck for the first time in our course we +may actually have a short lecture but + + align:start position:0% +may actually have a short lecture but + + + align:start position:0% +may actually have a short lecture but +let's see what actually goes on here + + align:start position:0% +let's see what actually goes on here + + + align:start position:0% +let's see what actually goes on here +let's not be too presumptuous the three + + align:start position:0% +let's not be too presumptuous the three + + + align:start position:0% +let's not be too presumptuous the three +cases are this either a s is greater + + align:start position:0% +cases are this either a s is greater + + + align:start position:0% +cases are this either a s is greater +than b case one a squ is greater than b + + align:start position:0% +than b case one a squ is greater than b + + + align:start position:0% +than b case one a squ is greater than b +so R1 is equal to R2 and they're both + + align:start position:0% +so R1 is equal to R2 and they're both + + + align:start position:0% +so R1 is equal to R2 and they're both +real and in this case the general + + align:start position:0% +real and in this case the general + + + align:start position:0% +real and in this case the general +solution of the homogeneous equation Y + + align:start position:0% +solution of the homogeneous equation Y + + + align:start position:0% +solution of the homogeneous equation Y +Prime + 2 a y Prime + B yal 0 is simply + + align:start position:0% +Prime + 2 a y Prime + B yal 0 is simply + + + align:start position:0% +Prime + 2 a y Prime + B yal 0 is simply +a linear combination of e to the r1x and + + align:start position:0% +a linear combination of e to the r1x and + + + align:start position:0% +a linear combination of e to the r1x and +e to the r2x namely C1 e to the r1x plus + + align:start position:0% +e to the r2x namely C1 e to the r1x plus + + + align:start position:0% +e to the r2x namely C1 e to the r1x plus +C2 e to the + + align:start position:0% +C2 e to the + + + align:start position:0% +C2 e to the +r2x for the second case when A2 equal B + + align:start position:0% +r2x for the second case when A2 equal B + + + align:start position:0% +r2x for the second case when A2 equal B +in that case R1 equals R2 and because + + align:start position:0% +in that case R1 equals R2 and because + + + align:start position:0% +in that case R1 equals R2 and because +they're equal let me just call both of + + align:start position:0% +they're equal let me just call both of + + + align:start position:0% +they're equal let me just call both of +them R1 notice that if I came back up + + align:start position:0% +them R1 notice that if I came back up + + + align:start position:0% +them R1 notice that if I came back up +here this would really not be a general + + align:start position:0% +here this would really not be a general + + + align:start position:0% +here this would really not be a general +solution in this case because with R1 + + align:start position:0% +solution in this case because with R1 + + + align:start position:0% +solution in this case because with R1 +equal to R2 e to the r1x is a common + + align:start position:0% +equal to R2 e to the r1x is a common + + + align:start position:0% +equal to R2 e to the r1x is a common +factor I could then Con well amalgamate + + align:start position:0% +factor I could then Con well amalgamate + + + align:start position:0% +factor I could then Con well amalgamate +the two arbitrary constants here and + + align:start position:0% +the two arbitrary constants here and + + + align:start position:0% +the two arbitrary constants here and +write what that that y subg the general + + align:start position:0% +write what that that y subg the general + + + align:start position:0% +write what that that y subg the general +solution is just C1 + C2 * e to the r1x + + align:start position:0% +solution is just C1 + C2 * e to the r1x + + + align:start position:0% +solution is just C1 + C2 * e to the r1x +and if C1 and C2 are arbitrary constants + + align:start position:0% +and if C1 and C2 are arbitrary constants + + + align:start position:0% +and if C1 and C2 are arbitrary constants +then their sum is simply a arbitrary + + align:start position:0% +then their sum is simply a arbitrary + + + align:start position:0% +then their sum is simply a arbitrary +constant it turns out that in this + + align:start position:0% +constant it turns out that in this + + + align:start position:0% +constant it turns out that in this +particular case another solution of this + + align:start position:0% +particular case another solution of this + + + align:start position:0% +particular case another solution of this +equation meaning what another one other + + align:start position:0% +equation meaning what another one other + + + align:start position:0% +equation meaning what another one other +than e to the r1x which is not a + + align:start position:0% +than e to the r1x which is not a + + + align:start position:0% +than e to the r1x which is not a +constant multiple of e to the r1x is x e + + align:start position:0% +constant multiple of e to the r1x is x e + + + align:start position:0% +constant multiple of e to the r1x is x e +to the r1x and we'll verify that later + + align:start position:0% +to the r1x and we'll verify that later + + + align:start position:0% +to the r1x and we'll verify that later +in the lecture for now just take this + + align:start position:0% +in the lecture for now just take this + + + align:start position:0% +in the lecture for now just take this +for granted and in that case it turns + + align:start position:0% +for granted and in that case it turns + + + align:start position:0% +for granted and in that case it turns +out that the general solution is given + + align:start position:0% +out that the general solution is given + + + align:start position:0% +out that the general solution is given +by the linear combination of e to the R1 + + align:start position:0% +by the linear combination of e to the R1 + + + align:start position:0% +by the linear combination of e to the R1 +x and x e to the r1x C1 e to the r1x + + align:start position:0% +x and x e to the r1x C1 e to the r1x + + + align:start position:0% +x and x e to the r1x C1 e to the r1x +plus C2 x e to the r1x in the third case + + align:start position:0% +plus C2 x e to the r1x in the third case + + + align:start position:0% +plus C2 x e to the r1x in the third case +we have that a s is less than B that + + align:start position:0% +we have that a s is less than B that + + + align:start position:0% +we have that a s is less than B that +means that R1 and R2 are complex complex + + align:start position:0% +means that R1 and R2 are complex complex + + + align:start position:0% +means that R1 and R2 are complex complex +conjugates which means that R has the + + align:start position:0% +conjugates which means that R has the + + + align:start position:0% +conjugates which means that R has the +form a real number plus or minus I times + + align:start position:0% +form a real number plus or minus I times + + + align:start position:0% +form a real number plus or minus I times +a real number calling the real part + + align:start position:0% +a real number calling the real part + + + align:start position:0% +a real number calling the real part +Alpha and the imaginary part beta all + + align:start position:0% +Alpha and the imaginary part beta all + + + align:start position:0% +Alpha and the imaginary part beta all +we're saying is if a^2 minus B is + + align:start position:0% +we're saying is if a^2 minus B is + + + align:start position:0% +we're saying is if a^2 minus B is +negative Alpha is playing the role of a + + align:start position:0% +negative Alpha is playing the role of a + + + align:start position:0% +negative Alpha is playing the role of a +here and beta is just the negative of + + align:start position:0% +here and beta is just the negative of + + + align:start position:0% +here and beta is just the negative of +what's under the radical sign here in + + align:start position:0% +what's under the radical sign here in + + + align:start position:0% +what's under the radical sign here in +other words if a^ minus B is negative B + + align:start position:0% +other words if a^ minus B is negative B + + + align:start position:0% +other words if a^ minus B is negative B +minus a s is positive in other words the + + align:start position:0% +minus a s is positive in other words the + + + align:start position:0% +minus a s is positive in other words the +beta part is just B the square root of B + + align:start position:0% +beta part is just B the square root of B + + + align:start position:0% +beta part is just B the square root of B +minus a 2 you see and in this case it + + align:start position:0% +minus a 2 you see and in this case it + + + align:start position:0% +minus a 2 you see and in this case it +turns out that the general solution is a + + align:start position:0% +turns out that the general solution is a + + + align:start position:0% +turns out that the general solution is a +linear + + align:start position:0% +linear + + + align:start position:0% +linear +combination a very interesting one well + + align:start position:0% +combination a very interesting one well + + + align:start position:0% +combination a very interesting one well +let me factor out the e to the alpha x + + align:start position:0% +let me factor out the e to the alpha x + + + align:start position:0% +let me factor out the e to the alpha x +what it says is First Take e raised to + + align:start position:0% +what it says is First Take e raised to + + + align:start position:0% +what it says is First Take e raised to +the alpha x power where Alpha is the + + align:start position:0% +the alpha x power where Alpha is the + + + align:start position:0% +the alpha x power where Alpha is the +real part of our root R okay and then + + align:start position:0% +real part of our root R okay and then + + + align:start position:0% +real part of our root R okay and then +multiply that by a linear combination of + + align:start position:0% +multiply that by a linear combination of + + + align:start position:0% +multiply that by a linear combination of +sin beta X and cosine beta X where beta + + align:start position:0% +sin beta X and cosine beta X where beta + + + align:start position:0% +sin beta X and cosine beta X where beta +is the imaginary part of R by the way + + align:start position:0% +is the imaginary part of R by the way + + + align:start position:0% +is the imaginary part of R by the way +without going into this because the + + align:start position:0% +without going into this because the + + + align:start position:0% +without going into this because the +textbook does it very eloquently and + + align:start position:0% +textbook does it very eloquently and + + + align:start position:0% +textbook does it very eloquently and +we'll have enough exercises on this to + + align:start position:0% +we'll have enough exercises on this to + + + align:start position:0% +we'll have enough exercises on this to +hammer this home later notice the + + align:start position:0% +hammer this home later notice the + + + align:start position:0% +hammer this home later notice the +intrinsically different geometric nature + + align:start position:0% +intrinsically different geometric nature + + + align:start position:0% +intrinsically different geometric nature +of interpreting these various solutions + + align:start position:0% +of interpreting these various solutions + + + align:start position:0% +of interpreting these various solutions +for example in this particular case just + + align:start position:0% +for example in this particular case just + + + align:start position:0% +for example in this particular case just +speaking very quickly here we see the + + align:start position:0% +speaking very quickly here we see the + + + align:start position:0% +speaking very quickly here we see the +general solution is the sum of two + + align:start position:0% +general solution is the sum of two + + + align:start position:0% +general solution is the sum of two +exponentials coming down to here notice + + align:start position:0% +exponentials coming down to here notice + + + align:start position:0% +exponentials coming down to here notice +that if Alpha happened to be zero in + + align:start position:0% +that if Alpha happened to be zero in + + + align:start position:0% +that if Alpha happened to be zero in +other words if I were purely imaginary + + align:start position:0% +other words if I were purely imaginary + + + align:start position:0% +other words if I were purely imaginary +notice that the solution would be what + + align:start position:0% +notice that the solution would be what + + + align:start position:0% +notice that the solution would be what +we call oscillatory motion and if Alpha + + align:start position:0% +we call oscillatory motion and if Alpha + + + align:start position:0% +we call oscillatory motion and if Alpha +is not zero notice that e to the alpha x + + align:start position:0% +is not zero notice that e to the alpha x + + + align:start position:0% +is not zero notice that e to the alpha x +C1 cosine beta X Plus C2 sin beta X is + + align:start position:0% +C1 cosine beta X Plus C2 sin beta X is + + + align:start position:0% +C1 cosine beta X Plus C2 sin beta X is +an oscillation that is either blown up + + align:start position:0% +an oscillation that is either blown up + + + align:start position:0% +an oscillation that is either blown up +if Alpha is positive or shrunk if Alpha + + align:start position:0% +if Alpha is positive or shrunk if Alpha + + + align:start position:0% +if Alpha is positive or shrunk if Alpha +is negative in other words the + + align:start position:0% +is negative in other words the + + + align:start position:0% +is negative in other words the +oscillatory part stays here but if Alpha + + align:start position:0% +oscillatory part stays here but if Alpha + + + align:start position:0% +oscillatory part stays here but if Alpha +happens to be negative say as X gets + + align:start position:0% +happens to be negative say as X gets + + + align:start position:0% +happens to be negative say as X gets +very large e to the Alp X goes to zero + + align:start position:0% +very large e to the Alp X goes to zero + + + align:start position:0% +very large e to the Alp X goes to zero +that pulls this whole expression down to + + align:start position:0% +that pulls this whole expression down to + + + align:start position:0% +that pulls this whole expression down to +zero and that's the case where you get + + align:start position:0% +zero and that's the case where you get + + + align:start position:0% +zero and that's the case where you get +what's called damped oscillatory Motion + + align:start position:0% +what's called damped oscillatory Motion + + + align:start position:0% +what's called damped oscillatory Motion +in other words you get oscillation but + + align:start position:0% +in other words you get oscillation but + + + align:start position:0% +in other words you get oscillation but +the amplitude keeps shrinking you see + + align:start position:0% +the amplitude keeps shrinking you see + + + align:start position:0% +the amplitude keeps shrinking you see +physically different things start to + + align:start position:0% +physically different things start to + + + align:start position:0% +physically different things start to +happen here and this is a very + + align:start position:0% +happen here and this is a very + + + align:start position:0% +happen here and this is a very +interesting subtlety that just small + + align:start position:0% +interesting subtlety that just small + + + align:start position:0% +interesting subtlety that just small +changes change the entire solution or + + align:start position:0% +changes change the entire solution or + + + align:start position:0% +changes change the entire solution or +the meaning of the solution and maybe + + align:start position:0% +the meaning of the solution and maybe + + + align:start position:0% +the meaning of the solution and maybe +the best way to illustrate that is to + + align:start position:0% +the best way to illustrate that is to + + + align:start position:0% +the best way to illustrate that is to +show examples of all three of these + + align:start position:0% +show examples of all three of these + + + align:start position:0% +show examples of all three of these +cases where the examples almost look + + align:start position:0% +cases where the examples almost look + + + align:start position:0% +cases where the examples almost look +alike but let me show you what I mean + + align:start position:0% +alike but let me show you what I mean + + + align:start position:0% +alike but let me show you what I mean +for example we already saw last time + + align:start position:0% +for example we already saw last time + + + align:start position:0% +for example we already saw last time +that if y primeus 4 y Prime + 3 y equal + + align:start position:0% +that if y primeus 4 y Prime + 3 y equal + + + align:start position:0% +that if y primeus 4 y Prime + 3 y equal +0 then the general solution was C1 e to + + align:start position:0% +0 then the general solution was C1 e to + + + align:start position:0% +0 then the general solution was C1 e to +X Plus C2 e to 3x that's precisely this + + align:start position:0% +X Plus C2 e to 3x that's precisely this + + + align:start position:0% +X Plus C2 e to 3x that's precisely this +case here because if we look at the + + align:start position:0% +case here because if we look at the + + + align:start position:0% +case here because if we look at the +equation that determines R it's r^ 2 - 4 + + align:start position:0% +equation that determines R it's r^ 2 - 4 + + + align:start position:0% +equation that determines R it's r^ 2 - 4 +r + 3 0 that says that R1 is 1 R2 is + + align:start position:0% +r + 3 0 that says that R1 is 1 R2 is + + + align:start position:0% +r + 3 0 that says that R1 is 1 R2 is +three the roots are 1 and three so two + + align:start position:0% +three the roots are 1 and three so two + + + align:start position:0% +three the roots are 1 and three so two +solutions are e to x e to the 3x R1 and + + align:start position:0% +solutions are e to x e to the 3x R1 and + + + align:start position:0% +solutions are e to x e to the 3x R1 and +R2 are real and unequal that's exactly + + align:start position:0% +R2 are real and unequal that's exactly + + + align:start position:0% +R2 are real and unequal that's exactly +the type that we were talking about back + + align:start position:0% +the type that we were talking about back + + + align:start position:0% +the type that we were talking about back +here when we were talking about case one + + align:start position:0% +here when we were talking about case one + + + align:start position:0% +here when we were talking about case one +as far as case 2 is concerned notice + + align:start position:0% +as far as case 2 is concerned notice + + + align:start position:0% +as far as case 2 is concerned notice +that y Prime - 4 y Prime + 4 y = 0 leads + + align:start position:0% +that y Prime - 4 y Prime + 4 y = 0 leads + + + align:start position:0% +that y Prime - 4 y Prime + 4 y = 0 leads +to the equation r^ 2 - 4 r + 4 = 0 that + + align:start position:0% +to the equation r^ 2 - 4 r + 4 = 0 that + + + align:start position:0% +to the equation r^ 2 - 4 r + 4 = 0 that +factors into r - 2 s is z and that says + + align:start position:0% +factors into r - 2 s is z and that says + + + align:start position:0% +factors into r - 2 s is z and that says +that Ral 2 is a multiple root to + + align:start position:0% +that Ral 2 is a multiple root to + + + align:start position:0% +that Ral 2 is a multiple root to +illustrate case two again the proof + + align:start position:0% +illustrate case two again the proof + + + align:start position:0% +illustrate case two again the proof +coming shortly but not now what we're + + align:start position:0% +coming shortly but not now what we're + + + align:start position:0% +coming shortly but not now what we're +saying is that in this case e to 2X and + + align:start position:0% +saying is that in this case e to 2X and + + + align:start position:0% +saying is that in this case e to 2X and +x e to 2x will be non-constant multiples + + align:start position:0% +x e to 2x will be non-constant multiples + + + align:start position:0% +x e to 2x will be non-constant multiples +of one another that are solutions and + + align:start position:0% +of one another that are solutions and + + + align:start position:0% +of one another that are solutions and +that consequently the general solution + + align:start position:0% +that consequently the general solution + + + align:start position:0% +that consequently the general solution +will be C1 e to 2x plus c2x e to + + align:start position:0% +will be C1 e to 2x plus c2x e to + + + align:start position:0% +will be C1 e to 2x plus c2x e to +2x the third case is that I'll pick is y + + align:start position:0% +2x the third case is that I'll pick is y + + + align:start position:0% +2x the third case is that I'll pick is y +Prime - 4 y Prime + + 5 y = 0 which + + align:start position:0% +Prime - 4 y Prime + + 5 y = 0 which + + + align:start position:0% +Prime - 4 y Prime + + 5 y = 0 which +leads to the equation r^2 - 4 r + 5 = 0 + + align:start position:0% +leads to the equation r^2 - 4 r + 5 = 0 + + + align:start position:0% +leads to the equation r^2 - 4 r + 5 = 0 +and solving by the quadratic formula for + + align:start position:0% +and solving by the quadratic formula for + + + align:start position:0% +and solving by the quadratic formula for +R this leads to R = 4 + orus the < TK of + + align:start position:0% +R this leads to R = 4 + orus the < TK of + + + align:start position:0% +R this leads to R = 4 + orus the < TK of +16 - 20 /2 the < TK of 16 - 20 that's + + align:start position:0% +16 - 20 /2 the < TK of 16 - 20 that's + + + align:start position:0% +16 - 20 /2 the < TK of 16 - 20 that's +the < TK of -4 is 2 i 4 plus or - 2 I + + align:start position:0% +the < TK of -4 is 2 i 4 plus or - 2 I + + + align:start position:0% +the < TK of -4 is 2 i 4 plus or - 2 I +over 2 just leads to 2 plus or minus I + + align:start position:0% +over 2 just leads to 2 plus or minus I + + + align:start position:0% +over 2 just leads to 2 plus or minus I +since Alpha is the real part of the root + + align:start position:0% +since Alpha is the real part of the root + + + align:start position:0% +since Alpha is the real part of the root +Alpha will be two since beta is the + + align:start position:0% +Alpha will be two since beta is the + + + align:start position:0% +Alpha will be two since beta is the +magnitude of the imaginary part of the + + align:start position:0% +magnitude of the imaginary part of the + + + align:start position:0% +magnitude of the imaginary part of the +root beta will be one in this case Alpha + + align:start position:0% +root beta will be one in this case Alpha + + + align:start position:0% +root beta will be one in this case Alpha +is two beta is 1 and therefore the + + align:start position:0% +is two beta is 1 and therefore the + + + align:start position:0% +is two beta is 1 and therefore the +general solution is what e to 2x * C1 + + align:start position:0% +general solution is what e to 2x * C1 + + + align:start position:0% +general solution is what e to 2x * C1 +cosine X Plus C2 sinx and by the way + + align:start position:0% +cosine X Plus C2 sinx and by the way + + + align:start position:0% +cosine X Plus C2 sinx and by the way +before I leave this example here's what + + align:start position:0% +before I leave this example here's what + + + align:start position:0% +before I leave this example here's what +I meant by saying how subtle this was + + align:start position:0% +I meant by saying how subtle this was + + + align:start position:0% +I meant by saying how subtle this was +notice that all three of these equations + + align:start position:0% +notice that all three of these equations + + + align:start position:0% +notice that all three of these equations +are identical except for the coefficient + + align:start position:0% +are identical except for the coefficient + + + align:start position:0% +are identical except for the coefficient +of Y in the first equation the + + align:start position:0% +of Y in the first equation the + + + align:start position:0% +of Y in the first equation the +coefficient was of Y was three in the + + align:start position:0% +coefficient was of Y was three in the + + + align:start position:0% +coefficient was of Y was three in the +second equation four and in the third + + align:start position:0% +second equation four and in the third + + + align:start position:0% +second equation four and in the third +equation five other than that they all + + align:start position:0% +equation five other than that they all + + + align:start position:0% +equation five other than that they all +looked alike the equations and yet in + + align:start position:0% +looked alike the equations and yet in + + + align:start position:0% +looked alike the equations and yet in +one case we got the two real and unequal + + align:start position:0% +one case we got the two real and unequal + + + align:start position:0% +one case we got the two real and unequal +roots in the second case we got the real + + align:start position:0% +roots in the second case we got the real + + + align:start position:0% +roots in the second case we got the real +but equal roots and in the third case + + align:start position:0% +but equal roots and in the third case + + + align:start position:0% +but equal roots and in the third case +the non-real complex conjugates all + + align:start position:0% +the non-real complex conjugates all + + + align:start position:0% +the non-real complex conjugates all +right that's all there is to this lesson + + align:start position:0% +right that's all there is to this lesson + + + align:start position:0% +right that's all there is to this lesson +except for giving you some insight as to + + align:start position:0% +except for giving you some insight as to + + + align:start position:0% +except for giving you some insight as to +why these recipes hold from this point + + align:start position:0% +why these recipes hold from this point + + + align:start position:0% +why these recipes hold from this point +on the rest is drill that does there's + + align:start position:0% +on the rest is drill that does there's + + + align:start position:0% +on the rest is drill that does there's +not much more we can do other than to + + align:start position:0% +not much more we can do other than to + + + align:start position:0% +not much more we can do other than to +have you uh look to see what's happening + + align:start position:0% +have you uh look to see what's happening + + + align:start position:0% +have you uh look to see what's happening +and work on the exercises but I thought + + align:start position:0% +and work on the exercises but I thought + + + align:start position:0% +and work on the exercises but I thought +that it might help if I give you a few + + align:start position:0% +that it might help if I give you a few + + + align:start position:0% +that it might help if I give you a few +little supplementary notes as to why + + align:start position:0% +little supplementary notes as to why + + + align:start position:0% +little supplementary notes as to why +these things work out and they work out + + align:start position:0% +these things work out and they work out + + + align:start position:0% +these things work out and they work out +easily enough so I decided to do the + + align:start position:0% +easily enough so I decided to do the + + + align:start position:0% +easily enough so I decided to do the +supplementary notes as part of the + + align:start position:0% +supplementary notes as part of the + + + align:start position:0% +supplementary notes as part of the +lecture namely first of all notice that + + align:start position:0% +lecture namely first of all notice that + + + align:start position:0% +lecture namely first of all notice that +in the case where R1 is unequal to R2 + + align:start position:0% +in the case where R1 is unequal to R2 + + + align:start position:0% +in the case where R1 is unequal to R2 +and they're both real that e to the r1x + + align:start position:0% +and they're both real that e to the r1x + + + align:start position:0% +and they're both real that e to the r1x +and e to the r2x are both real solutions + + align:start position:0% +and e to the r2x are both real solutions + + + align:start position:0% +and e to the r2x are both real solutions +and more importantly since one cannot be + + align:start position:0% +and more importantly since one cannot be + + + align:start position:0% +and more importantly since one cannot be +a constant multiple of the other their + + align:start position:0% +a constant multiple of the other their + + + align:start position:0% +a constant multiple of the other their +linear combination must be the general + + align:start position:0% +linear combination must be the general + + + align:start position:0% +linear combination must be the general +Solution that's what we saw last time + + align:start position:0% +Solution that's what we saw last time + + + align:start position:0% +Solution that's what we saw last time +remember the only time you were in + + align:start position:0% +remember the only time you were in + + + align:start position:0% +remember the only time you were in +trouble is if one was a constant + + align:start position:0% +trouble is if one was a constant + + + align:start position:0% +trouble is if one was a constant +multiple of the other why can't e to the + + align:start position:0% +multiple of the other why can't e to the + + + align:start position:0% +multiple of the other why can't e to the +r1x and e to the r2x be constant + + align:start position:0% +r1x and e to the r2x be constant + + + align:start position:0% +r1x and e to the r2x be constant +multiples of one another the answer + + align:start position:0% +multiples of one another the answer + + + align:start position:0% +multiples of one another the answer +quite simply is this assume that they + + align:start position:0% +quite simply is this assume that they + + + align:start position:0% +quite simply is this assume that they +were divide both sides by e to the r2x + + align:start position:0% +were divide both sides by e to the r2x + + + align:start position:0% +were divide both sides by e to the r2x +we then get e to the R1 - r2x as a + + align:start position:0% +we then get e to the R1 - r2x as a + + + align:start position:0% +we then get e to the R1 - r2x as a +constant but look at this is e raised to + + align:start position:0% +constant but look at this is e raised to + + + align:start position:0% +constant but look at this is e raised to +a very power the only way that e raed to + + align:start position:0% +a very power the only way that e raed to + + + align:start position:0% +a very power the only way that e raed to +a variable power can be a constant is if + + align:start position:0% +a variable power can be a constant is if + + + align:start position:0% +a variable power can be a constant is if +the multiplier of the x is itself zero + + align:start position:0% +the multiplier of the x is itself zero + + + align:start position:0% +the multiplier of the x is itself zero +so the X doesn't appear here in other + + align:start position:0% +so the X doesn't appear here in other + + + align:start position:0% +so the X doesn't appear here in other +words in that case notice that R1 minus + + align:start position:0% +words in that case notice that R1 minus + + + align:start position:0% +words in that case notice that R1 minus +R2 must be zero and that's the same as + + align:start position:0% +R2 must be zero and that's the same as + + + align:start position:0% +R2 must be zero and that's the same as +saying that R1 equals R2 in other words + + align:start position:0% +saying that R1 equals R2 in other words + + + align:start position:0% +saying that R1 equals R2 in other words +the only way that e to the r1x can be a + + align:start position:0% +the only way that e to the r1x can be a + + + align:start position:0% +the only way that e to the r1x can be a +constant multiple of e to the r2x is if + + align:start position:0% +constant multiple of e to the r2x is if + + + align:start position:0% +constant multiple of e to the r2x is if +R1 equals R2 but we're given in case one + + align:start position:0% +R1 equals R2 but we're given in case one + + + align:start position:0% +R1 equals R2 but we're given in case one +that R1 is not equal to R2 that's why + + align:start position:0% +that R1 is not equal to R2 that's why + + + align:start position:0% +that R1 is not equal to R2 that's why +the solution works as far as case 2 is + + align:start position:0% +the solution works as far as case 2 is + + + align:start position:0% +the solution works as far as case 2 is +concerned notice that what we have to + + align:start position:0% +concerned notice that what we have to + + + align:start position:0% +concerned notice that what we have to +establish is it's obvious that x e to + + align:start position:0% +establish is it's obvious that x e to + + + align:start position:0% +establish is it's obvious that x e to +the r1x is not a constant multiple of e + + align:start position:0% +the r1x is not a constant multiple of e + + + align:start position:0% +the r1x is not a constant multiple of e +to the r1x after all their ratio is X + + align:start position:0% +to the r1x after all their ratio is X + + + align:start position:0% +to the r1x after all their ratio is X +which is not a constant the hard thing + + align:start position:0% +which is not a constant the hard thing + + + align:start position:0% +which is not a constant the hard thing +to do is to justify how we can find out + + align:start position:0% +to do is to justify how we can find out + + + align:start position:0% +to do is to justify how we can find out +that x e to the r1x is a solution in + + align:start position:0% +that x e to the r1x is a solution in + + + align:start position:0% +that x e to the r1x is a solution in +that case and the answer is look at that + + align:start position:0% +that case and the answer is look at that + + + align:start position:0% +that case and the answer is look at that +that case occurs when A2 equals B if a 2 + + align:start position:0% +that case occurs when A2 equals B if a 2 + + + align:start position:0% +that case occurs when A2 equals B if a 2 +equals B notice that y Prime + 2 a y + + align:start position:0% +equals B notice that y Prime + 2 a y + + + align:start position:0% +equals B notice that y Prime + 2 a y +Prime + b y becomes replaced by y Prime + + align:start position:0% +Prime + b y becomes replaced by y Prime + + + align:start position:0% +Prime + b y becomes replaced by y Prime ++ 2 a y Prime + a^ 2 y now we very + + align:start position:0% ++ 2 a y Prime + a^ 2 y now we very + + + align:start position:0% ++ 2 a y Prime + a^ 2 y now we very +cleverly invoke the trick of writing 2 a + + align:start position:0% +cleverly invoke the trick of writing 2 a + + + align:start position:0% +cleverly invoke the trick of writing 2 a +y Prime as a y prime plus a y Prime see + + align:start position:0% +y Prime as a y prime plus a y Prime see + + + align:start position:0% +y Prime as a y prime plus a y Prime see +we take this and write it like this now + + align:start position:0% +we take this and write it like this now + + + align:start position:0% +we take this and write it like this now +we factor out an a from this expression + + align:start position:0% +we factor out an a from this expression + + + align:start position:0% +we factor out an a from this expression +here we have a * y Prime + a y notice + + align:start position:0% +here we have a * y Prime + a y notice + + + align:start position:0% +here we have a * y Prime + a y notice +that these two terms are just the + + align:start position:0% +that these two terms are just the + + + align:start position:0% +that these two terms are just the +derivative of y Prime + a y in other + + align:start position:0% +derivative of y Prime + a y in other + + + align:start position:0% +derivative of y Prime + a y in other +words if I let you equal y Prime + a y + + align:start position:0% +words if I let you equal y Prime + a y + + + align:start position:0% +words if I let you equal y Prime + a y +then this being u means that with the + + align:start position:0% +then this being u means that with the + + + align:start position:0% +then this being u means that with the +Prime on this this is U Prime this just + + align:start position:0% +Prime on this this is U Prime this just + + + align:start position:0% +Prime on this this is U Prime this just +becomes U Prime + Au U equals z that's a + + align:start position:0% +becomes U Prime + Au U equals z that's a + + + align:start position:0% +becomes U Prime + Au U equals z that's a +first order differential equation in U + + align:start position:0% +first order differential equation in U + + + align:start position:0% +first order differential equation in U +in which the variables are separable see + + align:start position:0% +in which the variables are separable see + + + align:start position:0% +in which the variables are separable see +in other words this becomes this from + + align:start position:0% +in other words this becomes this from + + + align:start position:0% +in other words this becomes this from +this I can very quickly find that U is + + align:start position:0% +this I can very quickly find that U is + + + align:start position:0% +this I can very quickly find that U is +equal to c e to minus ax I didn't want C + + align:start position:0% +equal to c e to minus ax I didn't want C + + + align:start position:0% +equal to c e to minus ax I didn't want C +I wanted I didn't want U I wanted y I + + align:start position:0% +I wanted I didn't want U I wanted y I + + + align:start position:0% +I wanted I didn't want U I wanted y I +remember that by definition of my + + align:start position:0% +remember that by definition of my + + + align:start position:0% +remember that by definition of my +substitution U is y Prime + a y + + align:start position:0% +substitution U is y Prime + a y + + + align:start position:0% +substitution U is y Prime + a y +consequently this leads to Y Prime + a y + + align:start position:0% +consequently this leads to Y Prime + a y + + + align:start position:0% +consequently this leads to Y Prime + a y +is c e to the minus ax this is a first + + align:start position:0% +is c e to the minus ax this is a first + + + align:start position:0% +is c e to the minus ax this is a first +order linear differential equation we + + align:start position:0% +order linear differential equation we + + + align:start position:0% +order linear differential equation we +learned how to solve that in a previous + + align:start position:0% +learned how to solve that in a previous + + + align:start position:0% +learned how to solve that in a previous +unit leaving the details again to you it + + align:start position:0% +unit leaving the details again to you it + + + align:start position:0% +unit leaving the details again to you it +now follows that a particular solution + + align:start position:0% +now follows that a particular solution + + + align:start position:0% +now follows that a particular solution +of this equation will be Y subp is x e + + align:start position:0% +of this equation will be Y subp is x e + + + align:start position:0% +of this equation will be Y subp is x e +to the minus ax recalling that in this + + align:start position:0% +to the minus ax recalling that in this + + + align:start position:0% +to the minus ax recalling that in this +case R1 is minus a this is x e to the + + align:start position:0% +case R1 is minus a this is x e to the + + + align:start position:0% +case R1 is minus a this is x e to the +r1x this together with e to the r1x form + + align:start position:0% +r1x this together with e to the r1x form + + + align:start position:0% +r1x this together with e to the r1x form +your two linearly independent Solutions + + align:start position:0% +your two linearly independent Solutions + + + align:start position:0% +your two linearly independent Solutions +and consequently that's why the general + + align:start position:0% +and consequently that's why the general + + + align:start position:0% +and consequently that's why the general +solution in this case is C1 e to the r1x + + align:start position:0% +solution in this case is C1 e to the r1x + + + align:start position:0% +solution in this case is C1 e to the r1x +plus c2x e to the r1x the third case + + align:start position:0% +plus c2x e to the r1x the third case + + + align:start position:0% +plus c2x e to the r1x the third case +where we got the imaginary roots or the + + align:start position:0% +where we got the imaginary roots or the + + + align:start position:0% +where we got the imaginary roots or the +non-real roots hinges on a very + + align:start position:0% +non-real roots hinges on a very + + + align:start position:0% +non-real roots hinges on a very +interesting property of linearity plus + + align:start position:0% +interesting property of linearity plus + + + align:start position:0% +interesting property of linearity plus +complex functions if u and v are real + + align:start position:0% +complex functions if u and v are real + + + align:start position:0% +complex functions if u and v are real +notice that L of U plus IV by linearity + + align:start position:0% +notice that L of U plus IV by linearity + + + align:start position:0% +notice that L of U plus IV by linearity +is L of U plus I L of V because after + + align:start position:0% +is L of U plus I L of V because after + + + align:start position:0% +is L of U plus I L of V because after +all I is a constant be it imaginary or + + align:start position:0% +all I is a constant be it imaginary or + + + align:start position:0% +all I is a constant be it imaginary or +otherwise consequently by linearity + + align:start position:0% +otherwise consequently by linearity + + + align:start position:0% +otherwise consequently by linearity +since L of u+ i v is L of U plus I L of + + align:start position:0% +since L of u+ i v is L of U plus I L of + + + align:start position:0% +since L of u+ i v is L of U plus I L of +V the only way that L of U plus I V can + + align:start position:0% +V the only way that L of U plus I V can + + + align:start position:0% +V the only way that L of U plus I V can +equal zero is if L of U plus I L of V + + align:start position:0% +equal zero is if L of U plus I L of V + + + align:start position:0% +equal zero is if L of U plus I L of V +equals z and the only way a complex + + align:start position:0% +equals z and the only way a complex + + + align:start position:0% +equals z and the only way a complex +number can equal zero is if both its + + align:start position:0% +number can equal zero is if both its + + + align:start position:0% +number can equal zero is if both its +real and imaginary parts are zero in + + align:start position:0% +real and imaginary parts are zero in + + + align:start position:0% +real and imaginary parts are zero in +other words then if L of U plus IV is + + align:start position:0% +other words then if L of U plus IV is + + + align:start position:0% +other words then if L of U plus IV is +zero it means that L of U and and L of V + + align:start position:0% +zero it means that L of U and and L of V + + + align:start position:0% +zero it means that L of U and and L of V +must themselves be zero see the real + + align:start position:0% +must themselves be zero see the real + + + align:start position:0% +must themselves be zero see the real +part must be zero the imaginary part + + align:start position:0% +part must be zero the imaginary part + + + align:start position:0% +part must be zero the imaginary part +must be zero now how do we apply this to + + align:start position:0% +must be zero now how do we apply this to + + + align:start position:0% +must be zero now how do we apply this to +case three notice that in case three we + + align:start position:0% +case three notice that in case three we + + + align:start position:0% +case three notice that in case three we +solved for R and got that R was equal to + + align:start position:0% +solved for R and got that R was equal to + + + align:start position:0% +solved for R and got that R was equal to +Alpha plus or minus I beta let me pick + + align:start position:0% +Alpha plus or minus I beta let me pick + + + align:start position:0% +Alpha plus or minus I beta let me pick +the positive root and we said our + + align:start position:0% +the positive root and we said our + + + align:start position:0% +the positive root and we said our +solution was e to the alpha plus I beta + + align:start position:0% +solution was e to the alpha plus I beta + + + align:start position:0% +solution was e to the alpha plus I beta +X now the idea is this looks quite + + align:start position:0% +X now the idea is this looks quite + + + align:start position:0% +X now the idea is this looks quite +imaginary and it is in this form but + + align:start position:0% +imaginary and it is in this form but + + + align:start position:0% +imaginary and it is in this form but +what we've just seen is that since this + + align:start position:0% +what we've just seen is that since this + + + align:start position:0% +what we've just seen is that since this +is a solution of this homogeneous + + align:start position:0% +is a solution of this homogeneous + + + align:start position:0% +is a solution of this homogeneous +equation the real and the imaginary part + + align:start position:0% +equation the real and the imaginary part + + + align:start position:0% +equation the real and the imaginary part +separately must be Solutions + + align:start position:0% +separately must be Solutions + + + align:start position:0% +separately must be Solutions +consequently if I write this in the in + + align:start position:0% +consequently if I write this in the in + + + align:start position:0% +consequently if I write this in the in +the traditional U plus IV form then u + + align:start position:0% +the traditional U plus IV form then u + + + align:start position:0% +the traditional U plus IV form then u +and v separately will also be Solutions + + align:start position:0% +and v separately will also be Solutions + + + align:start position:0% +and v separately will also be Solutions +well let's see how I write e to the + + align:start position:0% +well let's see how I write e to the + + + align:start position:0% +well let's see how I write e to the +alpha plus I beta X in traditional form + + align:start position:0% +alpha plus I beta X in traditional form + + + align:start position:0% +alpha plus I beta X in traditional form +first of all this is e to the alpha + + align:start position:0% +first of all this is e to the alpha + + + align:start position:0% +first of all this is e to the alpha +x time e to the I beta X by the rules of + + align:start position:0% +x time e to the I beta X by the rules of + + + align:start position:0% +x time e to the I beta X by the rules of +exponents we recall from our lecture on + + align:start position:0% +exponents we recall from our lecture on + + + align:start position:0% +exponents we recall from our lecture on +complex + + align:start position:0% +complex + + + align:start position:0% +complex +functions that e to the I beta X is cine + + align:start position:0% +functions that e to the I beta X is cine + + + align:start position:0% +functions that e to the I beta X is cine +beta X plus I sin beta X consequently e + + align:start position:0% +beta X plus I sin beta X consequently e + + + align:start position:0% +beta X plus I sin beta X consequently e +to the alpha plus I beta X is just e to + + align:start position:0% +to the alpha plus I beta X is just e to + + + align:start position:0% +to the alpha plus I beta X is just e to +the alpha x times this expression here + + align:start position:0% +the alpha x times this expression here + + + align:start position:0% +the alpha x times this expression here +or separating it into the form U plus i + + align:start position:0% +or separating it into the form U plus i + + + align:start position:0% +or separating it into the form U plus i +v e to the alpha plus I beta X is e to + + align:start position:0% +v e to the alpha plus I beta X is e to + + + align:start position:0% +v e to the alpha plus I beta X is e to +the alpha x cosine beta X which is a + + align:start position:0% +the alpha x cosine beta X which is a + + + align:start position:0% +the alpha x cosine beta X which is a +real number because Alpha and beta are + + align:start position:0% +real number because Alpha and beta are + + + align:start position:0% +real number because Alpha and beta are +real plus I * e to the alpha x sin beta + + align:start position:0% +real plus I * e to the alpha x sin beta + + + align:start position:0% +real plus I * e to the alpha x sin beta +X and e to the alpha x sin beta X is + + align:start position:0% +X and e to the alpha x sin beta X is + + + align:start position:0% +X and e to the alpha x sin beta X is +also a real number because Alpha and + + align:start position:0% +also a real number because Alpha and + + + align:start position:0% +also a real number because Alpha and +beta are real in other words you the + + align:start position:0% +beta are real in other words you the + + + align:start position:0% +beta are real in other words you the +alpha x cosine beta X that's the real + + align:start position:0% +alpha x cosine beta X that's the real + + + align:start position:0% +alpha x cosine beta X that's the real +part of this complex number V is e to + + align:start position:0% +part of this complex number V is e to + + + align:start position:0% +part of this complex number V is e to +the alpha x sin beta X which is the + + align:start position:0% +the alpha x sin beta X which is the + + + align:start position:0% +the alpha x sin beta X which is the +imaginary part of this since we've just + + align:start position:0% +imaginary part of this since we've just + + + align:start position:0% +imaginary part of this since we've just +seen that the real and the imaginary + + align:start position:0% +seen that the real and the imaginary + + + align:start position:0% +seen that the real and the imaginary +parts of this function must satisfy this + + align:start position:0% +parts of this function must satisfy this + + + align:start position:0% +parts of this function must satisfy this +equation also that tells us that e to + + align:start position:0% +equation also that tells us that e to + + + align:start position:0% +equation also that tells us that e to +the alpha x cosine beta X and e to the + + align:start position:0% +the alpha x cosine beta X and e to the + + + align:start position:0% +the alpha x cosine beta X and e to the +alpha x sin beta X also satisfy this + + align:start position:0% +alpha x sin beta X also satisfy this + + + align:start position:0% +alpha x sin beta X also satisfy this +equation and that by the way is exactly + + align:start position:0% +equation and that by the way is exactly + + + align:start position:0% +equation and that by the way is exactly +what we saw in case three only we + + align:start position:0% +what we saw in case three only we + + + align:start position:0% +what we saw in case three only we +factored out the e to the alpha x notice + + align:start position:0% +factored out the e to the alpha x notice + + + align:start position:0% +factored out the e to the alpha x notice +by the way that these two equations + + align:start position:0% +by the way that these two equations + + + align:start position:0% +by the way that these two equations +cannot be constant multiples of one + + align:start position:0% +cannot be constant multiples of one + + + align:start position:0% +cannot be constant multiples of one +another because if we divide say the top + + align:start position:0% +another because if we divide say the top + + + align:start position:0% +another because if we divide say the top +by the bottom the e to the alpha x + + align:start position:0% +by the bottom the e to the alpha x + + + align:start position:0% +by the bottom the e to the alpha x +cancel sin beta X over cosine beta X is + + align:start position:0% +cancel sin beta X over cosine beta X is + + + align:start position:0% +cancel sin beta X over cosine beta X is +tan beta X and for beta not equal to + + align:start position:0% +tan beta X and for beta not equal to + + + align:start position:0% +tan beta X and for beta not equal to +zero tan beta X can't be a constant so + + align:start position:0% +zero tan beta X can't be a constant so + + + align:start position:0% +zero tan beta X can't be a constant so +that these two solutions do indeed + + align:start position:0% +that these two solutions do indeed + + + align:start position:0% +that these two solutions do indeed +generate the general solution now that's + + align:start position:0% +generate the general solution now that's + + + align:start position:0% +generate the general solution now that's +all there is to this particular problem + + align:start position:0% +all there is to this particular problem + + + align:start position:0% +all there is to this particular problem +the rest as I say is left to the + + align:start position:0% +the rest as I say is left to the + + + align:start position:0% +the rest as I say is left to the +exercises what we're going to do next + + align:start position:0% +exercises what we're going to do next + + + align:start position:0% +exercises what we're going to do next +time is tackle the companion part of + + align:start position:0% +time is tackle the companion part of + + + align:start position:0% +time is tackle the companion part of +this problem and that is how do you find + + align:start position:0% +this problem and that is how do you find + + + align:start position:0% +this problem and that is how do you find +the particular solution of a linear + + align:start position:0% +the particular solution of a linear + + + align:start position:0% +the particular solution of a linear +differential equation with constant + + align:start position:0% +differential equation with constant + + + align:start position:0% +differential equation with constant +coefficients where the right hand side + + align:start position:0% +coefficients where the right hand side + + + align:start position:0% +coefficients where the right hand side +is not zero in other words the + + align:start position:0% +is not zero in other words the + + + align:start position:0% +is not zero in other words the +non-homogeneous case but more about that + + align:start position:0% +non-homogeneous case but more about that + + + align:start position:0% +non-homogeneous case but more about that +next time so until next time + + align:start position:0% + + + + align:start position:0% + +goodbye funding for the publication of + + align:start position:0% +goodbye funding for the publication of + + + align:start position:0% +goodbye funding for the publication of +this video was provided by the Gabriella + + align:start position:0% +this video was provided by the Gabriella + + + align:start position:0% +this video was provided by the Gabriella +and Paul rosenbom + + align:start position:0% +and Paul rosenbom + + + align:start position:0% +and Paul rosenbom +foundation help ocw continue to provide + + align:start position:0% +foundation help ocw continue to provide + + + align:start position:0% +foundation help ocw continue to provide +free and open access to MIT courses by + + align:start position:0% +free and open access to MIT courses by + + + align:start position:0% +free and open access to MIT courses by +making a donation at ocw.mit.edu/donate \ No newline at end of file diff --git a/DZ138JSpoxQ.txt b/DZ138JSpoxQ.txt new file mode 100644 index 0000000000000000000000000000000000000000..7299429e399c0339397a952ccccbe2a8af325f12 --- /dev/null +++ b/DZ138JSpoxQ.txt @@ -0,0 +1,1730 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high quality educational +resources for free. + +To make a donation, or view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu. + +PROFESSOR: So, now we'll start +on the last of the main topics + +in the course. + +So we've finished most of our +macroscopic thermodynamics, + +and our microscopic +approach to it + +through statistical mechanics. + +And now, our final topic +is kinetics. + +Kinetics is really a very +different kind of topic. + +Because unlike thermodynamics, +thermodynamics tells you all + +about equilibrium properties. + +A huge part of the work of this +term has been to figure + +out what equilibrium is. + +What is the equilibrium state, +given some situation. + +You've got some phases +present. + +Different then, you could go +from solid to liquid to gas. + +Or you've got different chemical +constituents together + +that can react and go +back and forth. + +What are the equilibrium +concentrations? + +But we haven't worried at all +about how long it might take + +to get there. + +And that's what kinetics does. + +Kinetics is concerned with rates +of reactions, primarily. + +How long it takes to +reach equilibrium. + +And of course it's +super-important. + +Because if you look at that +window glass, it's not in + +equilibrium. + +It's silicon dioxide, +the equilibrium + +state would be a crystal. + +It would be crystal +and quartz. + +Nevertheless, none of us is +very worried that on the + +moment it's likely to suddenly, +spontaneously turn + +into a crystal and be opaque and +scatter light and do all + +that sort of stuff. + +And in lots of other situations, +certainly if you + +look at any living biological +system, including yourselves + +or your friends or any other +one, it's certainly far from + +equilibrium. + +And you probably would hope +for it to stay that way. + +So there's an enormous amount +of chemistry and processes + +we're concerned with. + +Which depend intimately on +kinetics in order to work the + +way they work. + +They also do depend on +thermodynamics and where + +equilibrium states are. + +But that doesn't mean +they necessarily + +reach equilibrium states. + +So we're going to go through +kinetics, starting with the + +simplest examples and working +our way up to + +more complex cases. + +And just see how we can describe +elementary chemical + +reaction rates and processes. + +So that's our concern +now, is dynamics. + +How long things take to +get to equilibrium. + +And actually just like +macroscopic thermodynamics, + +kinetics does take an empirical + +approach to the topic. + +In other words, it's based on +experimental observation. + +Of macroscopic rates. + +How long it takes a collection +of stuff, a mole of stuff to + +change chemically. + +And undergo reaction. + +And so forth. + +We often infer molecular +mechanisms based on kinetics. + +And it's hugely important +and valuable to do that. + +But it's also important to +recognize that what kinetics + +can do is show us how we can +formulate microscopic + +mechanisms that might be +consistent with our + +macroscopic kinetics models. + +But the kinetics models +by themselves + +don't prove the mechanism. + +And there are all sorts of +examples where mechanisms that + +were proposed and accepted +because they were consistent + +with macroscopic kinetics +results turned out to fail. + +There are other ways to +prove mechanisms. + +You might be able to design +direct spectroscopic + +observations of intermediates +and so forth. + +And in that case, it often +becomes possible to + +distinguish between different +mechanisms. + +Which might all satisfy the +macroscopic kinetics equation. + +So we use kinetics to infer a +mechanism but not necessarily + +to prove it. + +Not generally to prove it. + +We also use kinetics to describe +an enormous range of + +time scales. + +So, the fastest things that +we're sometimes concerned with + +that might take place on +femtosecond time scales, 10 to + +the minus 13 seconds +or so, or 10 to the + +minus 15 seconds, even. + +So, if we look at the range +of time scales we might be + +concerned with, might go +anywhere from about 10 to the + +minus 15 seconds at the fastest, +and might go to + +enormous scales on +the other end. + +All the way out to maybe 10 to +the 10 seconds, which is on + +the thousands of years. + +Could be longer than +that, sometimes + +even millions of years. + +And the formalism that we'll set +up applies equally to the + +full range of time scales. + +So it can describe an enormous +amount of chemical activity. + +More commonly, for stuff that +we're going to compare to, you + +might measure in the lab. + +Common time scales range from +roughly 10 to the minus 6 + +seconds out to about 10 +to the 5th seconds. + +That is, microseconds +to about a day. + +But there are plenty of examples +of going either + +faster or slower, depending on +the need and the experimental + +equipment available. + +Let's define a few terms. + +Let's talk about how we're +going to just formulate + +chemical reaction rates. + +So, let's just imagine any +simple reaction of this sort. + +So A plus B are going to go to +C. There's some rate at which + +it happens. + +Note, by the way, it's an +arrow in one direction. + +It's not an equals sign +like we've seen + +before, or a double arrow. + +So the point I'm emphasizing +here is when we talk about + +reaction rates, unlike +equilibria, we're talking + +about a particular direction. + +Later on, we will talk about +reversible reactions. + +But there, too, the arrow going +this way refers only to + +one of the chemical reactions +that can take place. + +Namely, in this case, the +changing of what was the + +product now, would be the +reactant, C, back into A plus + +B and it has nothing to do +with the rate this way. + +Measured independently +and so on. + +So the rate, we can look at the +rate of disappearance of + +A. So it's just negative +d[A]/dt, where the brackets + +indicate concentration. + +Usually in moles per liter. + +If it's in a gas, then it would +be pA, of pressure. + +So negative d[A]/dt +is our rate. + +And note that that's generally +a positive number. + +We're looking at reactions +going, if it's a reaction + +going in this direction. + +A is gradually disappearing. + +So we're going to define +our rate this way. + +To be a positive number. + +The rate for C is going +to be plus d[C]/dt. + +It's also going to be +defined in a way + +that makes it positive. + +Because in this case, since the +reaction's going this way, + +we're looking at the +appearance of C. + +Now, by stoichiometry , in this +case, of course whenever + +a molecule or a mole of A +disappears, a molecule or a + +mole of C appears. + +So because of that, in this +case, the stoichiometry tells + +us that that d[C]/dt is equal +to negative d[A]/dt. + +And also equal to negative +d[B]/dt. + +And any of those can be used to + +define the rate of reaction. + +Now, this is a particularly +simple case because I've + +chosen the case where all +of the stoichiometric + +coefficients are equal to one. + +So now let's just look at any +case that's different. + +Let's look at 2A plus B goes to +something else, 3C plus D. + +And just look at the reaction +rates that we might see there. + +So here now, the appearance of +C is going to be three times + +as fast as the appearance +of D, for example. + +And also three times as fast as +the disappearance of B. So + +if we write negative d[B]/dt, +we expect that's going to be + +negative 1/2 d[A]/dt. + +In other words, A is going to +disappear twice as fast as B. + +Every time a molecule of B +reacts, two molecules of A do. + +And that's going to be plus 1/3 +d[C]/dt, and every time + +that happens three molecules +of C get formed. + +And it's going to +be plus d[D]/dt. + +One molecule of D gets formed. + +And so, the reaction rate could +be defined in terms of + +any of these. + +But the important thing is to +keep track of stoichiometry so + +that the rate as it pertains +to each constituent is + +accounted for correctly. + +So to generalize, if I have +little a of A, and little b of + +B, going to little c of C, and +little d of D, then the rate + +of reaction can be written as +minus one over a d[A]/dt, or + +minus one over b d[B]/dt, or +one over c d[C]/dt, or one + +over d d[D]/dt. + +So, experimentally, lots of +measurements of reaction rates + +have been made. + +And now to start on what's seen +empirically, basically + +the following result is +extremely common. + +The rate is equal to some +constant times the + +concentration of A to some +power alpha, times the + +concentration of B to some +power beta, and so on. + +For all reactants. + +Multiplied together, +each concentration + +taken to some power. + +Notice no products. + +Again, we're only looking at +a reaction going one way. + +And if we look at the +rate, this is + +typically what's found. + +Alpha is called the order of +reaction, with respect to A. + +Beta order with respect +to B. And so on. + +And little k is our rate +constant which, just to make + +clear, since we've been using it +extensively in the past few + +lectures, is completely +not equal to + +the Boltzmann constant. + +Absolutely no connection +between them. + +Now, alpha and beta, what they +are, what they turn out to be, + +is typically what's determined +as a result of kinetic + +measurement. + +Typically they're +small integers. + +So, just sort of a typical +example, if you look at the + +reaction of NO and O2, to make +NO2, simple reaction, and you + +look at minus d[O2]/dt, use +that as a measure of the + +reaction rate. + +What's found is that it's +a constant times NO + +concentration squared, +times O2. + +Simple, right? + +One of the exponents is +two, the other's one. + +Doesn't seem so surprising +mechanistically. + +But it's not always the case. + +Even when you have small +integers, it's not always the + +case that the most obvious +mechanism you would infer is + +the real mechanism. + +And sometimes those exponents +don't turn + +out even to be integers. + +But here's another example. + +If you just look it CH3CHO going +to methane and carbon + +monoxide, seems like it would +be a pretty straightforward + +thing, too. + +So if you measure, for +example, the rate of + +appearance of methane, what +you discover is that it's + +equal to a constant times the +concentration of the starting + +material to the 3/2 power. + +Not obvious mechanistically why +that should be the case. + +Usually it's telling +us something. + +It's telling us that the +reaction mechanism is + +complicated. + +It's a multi-step process. + +Sometimes there could be chain +reactions and so forth. + +So again, seeing things like +this certainly helps us to + +infer molecular mechanisms. + +Again, they don't prove +molecular mechanisms. + +But they certainly can be very +helpful in suggesting them. + +And then other means can be +used to try to prove them. + +Including, above all, direct +observation of the + +intermediates that you would +expect on the basis of one + +mechanism or another. + +Now let's just go through some +elementary examples of + +kinetics one at a time. + +So let's start with the simplest +possible case. + +Actually, a very rare case, but +one that'll help us just + +set up the formalism +of, and the + +mechanism for us to proceed. + +So let's talk about zero +order reactions. + +Actually very rare. + +So, what this means is +something like A + +goes over to products. + +Make a measurement of d[A]/dt, +and discover that it's k time + +A to the power of zero, +that is, it's just k. + +There's no dependence on the +concentration of A. Or + +anything else. + +And you have some rate +of its disappearance. + +So here's an example of it. + +You could have oxalic acid, +and it just turns into + +hydrogen carbon dioxide +and carbon dioxide. + +Things break apart, forms +these products. + +Make a measurement of +the disappearance. + +Seems to have nothing to do with +the concentration of it. + +At least under certain +conditions. + +Now, turns out that there's +another element that helps + +understand this. + +Turns out that light +is needed, it's a + +photochemical reaction. + +And then it's easy to see +how this can happen. + +Let's say we have an abundance +of the starting material, and + +not very much light. + +So every now and then photons +bleed in, and every now and + +then when they're absorbed, +it leads to dissociation. + +In that situation, you'll be +limited by the photons, but + +not by the concentration +of the molecules. + +And in fact, strictly speaking +although this is zero order in + +terms of the chemical +constituents, it's not zero + +order in the photons. + +So in some sense, in this sort +of situation, the photons + +should be considered one +of the reactants. + +You could write this as this +plus h nu plus one photon, + +goes over to these products. + +And then if you measure the +rate and things are under + +circumstances like I described, +you would discover + +that in fact yes you'd +be photon limited. + +The rate would depend +on how many both + +photons are coming in. + +Still, ordinarily, chemical +rate equations aren't + +formulated in those terms. + +So in the usual formulation, +this would still have the + +appearance of a zero +order reaction. + +Now, how do we write and +formulate a solution? + +So it's simple. + +We've we've written a +differential equation here. + +It's a pretty straightforward +one. + +Minus d[A]/dt is just +a constant. + +So we can solve it. + +And typically we'll solve it by +rewriting in integral form + +and then doing the integration +as long as we can do the + +integration. + +So from here we can write the +integral from starting + +concentration [A]0 to some other +concentration, [A], d[A] + +is equal to minus k integral +from zero to t dt. + +So all we've done is integrate +on both sides. + +And we've assumed a starting +concentration. + +We've assumed an initial +condition. + +And we've also assumed an +initial time, which usually we + +can just call zero. + +And this is, of course, +something we can solve for + +straight away. + +So we just have that [A] minus +[A]0 is negative kt minus + +zero, which is minus kt. + +So [A] is minus kt. + +Plus [A]0. + +In other words, the +concentration of [A] at any + +time is given by the initial +concentration, minus the rate + +constant times time. + +It decays linearly in time. + +So we can sketch that. + +This is our initial +concentration. + +And then it's just going to +decline with time after that. + +And there's our solution. + +In lots of cases, it's +useful to define + +what's called a half-life. + +It's just useful. + +Because it provides some +timeframe, a single number + +that's a timeframe on which +the reaction occurs. + +So, the half-life is just the +time that it takes for half of + +the reactants to disappear. +t 1/2 time to + +react half the reactants. + +OK, so in this case it's +straightforward to see when + +that happens. + +In other words, that's the +time at which this + +concentration of A is just +equal to [A]0 over two. + +So we have [A]0 over two is +minus kt 1/2 plus [A]0 or t + +1/2 is equal to [A] over 2k. + +[A]0 over 2k. + +So there's our half-life. + +So if we go over here, +we can put that in. + +[A]0 over two, and this +time is our half-life. + +So that's zero order +reactions. + +And, again, zero order +reactions are rare. + +But the procedure we're going to +used to solve for kinetics + +is outlined in this way. + +And we'll use that +again and again. + +Let's look at first-order +kinetics. + +Let's go over here. + +Now, first order reactions +are quite common. + +Much, much more common +than zero order. + +So here, you have A +goes to products. + +That's the simplest case. + +But this time if we measure +d[A]/dt, we discover that it's + +equal to a constant times the +concentration of A. There's an + +important point to note here. + +What are the units of +k, in this case. + +What do they have to be? + +Yeah, reciprocal +seconds right? + +The equation has to work. + +This is concentration +per second. + +This is concentration. + +This better be per second. + +Let's just, before we move on +completely, look at this. + +What are its units? + +Here's the equation. + +What are the units of k? + +No, not unitless, because, +look at this. + +This is some concentration +unit, + +typically moles per liter. + +So this is moles per liter +per second, right? + +It's disappearance of some +concentration for time. + +That's got to be here. + +All that is here. + +Moles per liter per second. + +So in every case, the units of +k, the rate constant, have to + +be figured out on the basis of +the specific rate equation. + +Doesn't have the same units. + +When the kinetics are +of different order. + +Now, let's solve this using the +same approach as before. + +Namely, this is still a +pretty straightforward + +differential equation. + +So let's just integrate +both sides. + +So that is going to tell us the +integral from [A]0 to [A]. + +But now we have [A] +on this side. + +So here we just had +a constant. + +And effectively, I didn't +write it out. + +But we effectively wrote this, +rewrote this, as d[A] + +equals minus k dt, +and then went + +from here to the integral. + +We're going to do the +same thing here, + +except now there's this. + +So really we're going +to have d[A] + +over [A] is minus k dt. + +That's what we're going to +integrate on both side. + +We need to have the variables +distinct on each side. + +So we have d[A] + +over [A]. + +Equal to minus k integral +from zero to t dt. + +And so, of course, you know +how to do this integral. + +It's going to look +like log of [A]. + +And again, it's taken +at [A] or, at [A]0. + +So we have log of +[A] over [A]0. + +We're going to have log of [A] +minus log of [A]0 coming out. + +And that's equal to minus kt. + +So now the kinetics are +quite different. + +We have [A] is equal to [A]0, +e to the minus kt. + +Very important, very common +sort of result. + +It's saying we start with a +certain amount of material, + +and there's an exponential +decay of it. + +So very different from +kinetics here, + +which are just linear. + +And again the kinetics here, if +you imagine that situation + +where you've got starting +material and bleeding in + +gradually are photons, +presumably at the same rate, + +then sure that material you're +going to see the disappearance + +of it linearly with time. + +Just depending on the +rate at which the + +photons are coming in. + +Here it's very different +because, presumably, A is + +required in order to +do this reaction. + +It'll depend on how much. + +Because of course if there's +more of it, you'll just have + +more at any given time decaying +over to products. + +So you have an exponential +decay. + +So let's plot that. + +Here's [A], let's +make that [A]0. + +There it is. + +Now, let's look at what happens +to the product. + +So let's imagine that it's A +going to B, so of course minus + +d[A]/dt is just equal to +d[B]/dt, and the rate of + +appearance of B has to match the +rate of disappearance of + +A. Let's assume that we +don't have any of + +B present at first. + +So let's make [B]0 +equal to zero. + +Well then, [B] just has to equal +[A]0 minus [A], right? + +All the stuff that's left, all +of the A that has disappeared, + +that's given by this +difference. + +Is just equal to B. So that's +just [A]0 minus concentration + +of A, but that's just +given by that. + +Which is [A]0 e to +the minus kt. + +Or in other words, [B] is just +equal to [A]0 times one minus + +e to the minus kt. + +So at t equals zero, this +is zero and this is one. + +In other words, this is going +to be zero at first. + +And then it's going to grow in +with the same exponential form + +that this decayed. + +So, [B] is going to do +the exact opposite. + +It's going to be like this. + +So this is [B] of t and this is +[A] of t equals [A]0 e to + +the minus kt. + +Now, it's always useful to, +whenever possible, to plot + +these things linearly. + +Find a way to plot these +as straight lines. + +And of course in this case it's +straightforward to do + +that as a log plot. + +So if we take the log of both +sides, we know of course that + +the log of [A] is just minus kt, +plus the log of [A]0, so + +now let's look at that. + +Make this the log of [A]0 and +this is the log of [A] + +on the axis. + +That'll be time. + +So there's just some +linear decay now. + +And the slope is minus k. + +So experimentally, of course, +this'll be done typically as a + +simple way of determining it. + +Now, we also can usefully look +at the half life, in this + +case, in the case of first +order kinetics. + +So we have an expression +in general for [A]. + +So if we let [A] equal [A]0 over +two, at t equals t 1/2, + +that tells us that log of [A]0 +over two divided by [A]0 is + +minus kt to the 1/2. + +But this is just the log of two, +or log of two is over k + +is t to the 1/2. + +And so t to the 1/2 is +just 0.693 over k. + +So we can write that just +generally, completely + +independent of whatever [A] is, +also independent of what + +[A]0 is, and that makes sense. + +So the point is, if you have +something that just + +spontaneously decays into +products, maybe it's just + +gradual chemical decomposition +of something. + +Spontaneously, without the +participation of other + +constituents. + +There's a general half-life +that can be + +associated with that. + +That'll just be related +directly to + +the rate of the decay. + +So it's knowable and measurable +in a simple form. + +And again, the half-life +is always useful. + +Because it just gives a simple, +one-number measure of + +the rough timescale for +things to change. + +So if we go back to this plot, +and then once again here's our + +half concentration. + +And here's our t 1/2, just a +useful way of summarizing in a + +simple way, what happens. + +Yeah? + +STUDENT: [INAUDIBLE] + +PROFESSOR: Ooh. + +Well, I didn't think about it. + +But it isn't necessary +that that'll happen. + +Sure seems like it must be. + +When one is half decayed, the +other must be half formed as + +long as there wasn't any +B present at first. + +So yeah, thank you. + +Well, given that, something +needs to move. + +But let's pretend like I got it +right at this intersection. + +Even though it doesn't +look that good. + +So really it should be there. + +Thank you. + +So the single most common +example of first order + +kinetics of this form is +radioactive decay. + +You've got some radioactive +isotopic that can + +spontaneously decay into +some other nucleus. + +And of course, this is measured +and half-lives have + +been tabulated for lots +of cases of this sort. + +So a simple example. + +Let's look at carbon-14. + +It's got a nuclear +charge of six. + +It can decay into nitrogen-14 +through + +the loss of an electron. + +Happens. + +First order kinetics. + +Now, in the atmosphere, what +happens is this will end up, + +the 14C ends up getting +replenished.. + +Because from cosmic rays, what +can happen is in the + +atmosphere, you can have your +nitrogen plus a neutron will + +come and form 14C plus +a hydrogen atom. + +So in fact, the overall +concentration in the + +atmosphere of 14C tends to +be constant over time. + +But stuff that's formed down +here on Earth, with carbon, + +its content of 14C decays over +time, and it doesn't get + +replenished. + +So, let's think back +some long time ago. + +Here's a tree. we can +make it pretty. + +So it's got some concentration +of 14C that came from carbon + +dioxide in the atmosphere. + +That's what it started with. + +That's our starting point. + +At some point later, through +natural occurrence or human + +intervention, that tree +became horizontal. + +Then, and although we're looking +back here, let's call + +this our t equals zero. + +And our 14C concentration +at the time is our + +concentration at zero. + +Now let's say, shortly after +that, either right after + +because of deliberate action, +or shortly after because it + +was just discovered, somebody +decides to build something + +using that tree. + +So, early human craft. + +And then let's say lots later, +depending on your definition + +of lots, modern human, which can +be denoted by this style + +of hat, makes exciting +discovery. + +Terrific. + +And would like to know +how old is it. + +How long ago did all +that stuff happen. + +Let's assume this is also +approximately t equals zero. + +Well, so a log of [14C] + +over [14C]0. + +So this carbon dating, +all it's really doing + +is measuring that. + +It gives a number for it. + +And we know this because we're +assuming it hasn't changed any + +in all those years. + +In the atmosphere. + +It's different down here, +because the tree or the boat + +wasn't replenished. + +Not nearly as many cosmic +rays fell on it. + +So that's minus log of t. + +And it turns out the t +1/2 is 5,760 years. + +Amazing, that this can be +known down to ten years. + +But it is. + +So that says, k his 0.693 +divided by t to the 1/2, which + +is one over 8,312 years. + +So there's our answer, then. + +The time, how long ago that +happened, is just minus 8,312 + +years times the log of [14C] + +in the artifact. + +Divided by the log +of, by [14C] + +in the air. + +And the assumption again is that +this is the same now as + +it was back then. + +And there's a bigger number than +this, so it's a positive + +number overall. + +So in a fairly straightforward +way, we'll use first order + +kinetics to determine +the lifetime of + +something like this. + +Because we know the +rate constant. + +And everything else follows. + +Let's see. + +Next there's going to be +second order kinetics. + +But let me just stop here and +say just a word about the exam + +on Wednesday. + +So I've handed out an +information sheet about it. + +But I don't have anything very +different to say this time + +than I've had to say about +previous exams. + +Solve lots of problems. + +Go over the homework. + +Go over practice problems. + +Try last year's exam as +a sample exam when + +you're ready to do it. + +Try it under test conditions. + +There's nothing on the exam that +you're going to look at + +and say oh my God, how was I +supposed to know that we ought + +to study that. + +There won't be any surprises. + +Most of the exam questions so +far, not all have been easy, + +but I think they've been more +or less plain vanilla in the + +sense that they're right more +or less down the middle of + +what we're trying to teach. + +And not very many are taking off +little peripheral elements + +of the class. + +And it's not going to be +any different here. + +So if you can just do the +problem solving and get + +familiar enough with it that +you're just good at it, so + +that you can do it with a +reasonable speed, you're going + +to be fine. + +Also try to work on just +understanding the + +underpinnings. + +Especially of statistical +mechanics. + +That's where when you have these +true-false or multiple + +choice questions, these sort +of thought exercises. + +Those are really hard. + +Because they go a little bit +beyond problem solving. + +If you could do the +problem solving, + +you're going to do fine. + +But it's always useful if you +can also formulate things. + +And for that, it's never easy +to just tell you here's what + +you have to do, to +get good at this. + +Because you have to +think about it. + +And it's always hard. + +But to be sure, if you can just +try when you review the + +statistical mechanics, +especially, and you review the + +expressions that you use and +how you solve problems with + +them, the next step in studying +is to try to think, + +OK, do I really understand +where that + +expression came from. + +And why it makes sense +physically. + +And if you can do that, then +so much the better. + +Then you'll be in an even +stronger position. + +The info sheet gives a handful +of equations that we do expect + +you to come in with those +on your fingertips. + +There are not very many. + +Mostly we'll provide expressions +that you'll need, + +and the important thing is that +you know, understand, + +where they apply. + +And how to use them. + +So, good luck on Wednesday. \ No newline at end of file diff --git a/DaHJqeTDN1M.txt b/DaHJqeTDN1M.txt new file mode 100644 index 0000000000000000000000000000000000000000..19628526158c5ed85e1022fc0880e550a18d5b24 --- /dev/null +++ b/DaHJqeTDN1M.txt @@ -0,0 +1,1946 @@ +align:start position:0% + +hi everyone uh so for this problem we're + + align:start position:0% +hi everyone uh so for this problem we're + + + align:start position:0% +hi everyone uh so for this problem we're +just going to take a look at uh + + align:start position:0% +just going to take a look at uh + + + align:start position:0% +just going to take a look at uh +Computing some igen values and igen + + align:start position:0% +Computing some igen values and igen + + + align:start position:0% +Computing some igen values and igen +vectors of uh several matrices and this + + align:start position:0% +vectors of uh several matrices and this + + + align:start position:0% +vectors of uh several matrices and this +is just a review problem for exam number + + align:start position:0% +is just a review problem for exam number + + + align:start position:0% +is just a review problem for exam number +three so specifically we're given a + + align:start position:0% +three so specifically we're given a + + + align:start position:0% +three so specifically we're given a +projection Matrix which has the form of + + align:start position:0% +projection Matrix which has the form of + + + align:start position:0% +projection Matrix which has the form of +a a transpose divided by a transpose a + + align:start position:0% +a a transpose divided by a transpose a + + + align:start position:0% +a a transpose divided by a transpose a +where a is the vector 3 and four the + + align:start position:0% +where a is the vector 3 and four the + + + align:start position:0% +where a is the vector 3 and four the +second problem is for a rotation Matrix + + align:start position:0% +second problem is for a rotation Matrix + + + align:start position:0% +second problem is for a rotation Matrix +Q uh which is the number + + align:start position:0% +Q uh which is the number + + + align:start position:0% +Q uh which is the number +0.6.8 point8 + + align:start position:0% +0.6.8 point8 + + + align:start position:0% +0.6.8 point8 +and6 and then the third one is for a + + align:start position:0% +and6 and then the third one is for a + + + align:start position:0% +and6 and then the third one is for a +reflection Matrix uh which is 2p minus + + align:start position:0% +reflection Matrix uh which is 2p minus + + + align:start position:0% +reflection Matrix uh which is 2p minus +the identity so I'll let you uh work + + align:start position:0% +the identity so I'll let you uh work + + + align:start position:0% +the identity so I'll let you uh work +these out and then I'll come back in a + + align:start position:0% +these out and then I'll come back in a + + + align:start position:0% +these out and then I'll come back in a +second and I'll uh fill in my uh + + align:start position:0% +second and I'll uh fill in my uh + + + align:start position:0% +second and I'll uh fill in my uh +Solutions + + align:start position:0% + + + + align:start position:0% + +hi everyone welcome back okay so for the + + align:start position:0% +hi everyone welcome back okay so for the + + + align:start position:0% +hi everyone welcome back okay so for the +first problem uh we're given a matrix P + + align:start position:0% +first problem uh we're given a matrix P + + + align:start position:0% +first problem uh we're given a matrix P +which is a projection Matrix and from + + align:start position:0% +which is a projection Matrix and from + + + align:start position:0% +which is a projection Matrix and from +earlier on in the course we probably + + align:start position:0% +earlier on in the course we probably + + + align:start position:0% +earlier on in the course we probably +already know that the igen values of a + + align:start position:0% +already know that the igen values of a + + + align:start position:0% +already know that the igen values of a +projection Matrix are are either zero or + + align:start position:0% +projection Matrix are are either zero or + + + align:start position:0% +projection Matrix are are either zero or +one and I'll just recall how how do you + + align:start position:0% +one and I'll just recall how how do you + + + align:start position:0% +one and I'll just recall how how do you +know that well if x is is an igen Vector + + align:start position:0% +know that well if x is is an igen Vector + + + align:start position:0% +know that well if x is is an igen Vector +of + + align:start position:0% +of + + + align:start position:0% +of +P then it satisfies uh the equation PX + + align:start position:0% +P then it satisfies uh the equation PX + + + align:start position:0% +P then it satisfies uh the equation PX +Lambda X but for projection Matrix p^2 + + align:start position:0% +Lambda X but for projection Matrix p^2 + + + align:start position:0% +Lambda X but for projection Matrix p^2 +is equal to P so if p is a projection we + + align:start position:0% +is equal to P so if p is a projection we + + + align:start position:0% +is equal to P so if p is a projection we +have p^2 equal + + align:start position:0% +have p^2 equal + + + align:start position:0% +have p^2 equal +p and uh specifically what this means + + align:start position:0% +p and uh specifically what this means + + + align:start position:0% +p and uh specifically what this means +is uh p^2 + + align:start position:0% +is uh p^2 + + + align:start position:0% +is uh p^2 +X is equal to + + align:start position:0% +X is equal to + + + align:start position:0% +X is equal to +uh Lambda + + align:start position:0% +uh Lambda + + + align:start position:0% +uh Lambda +x uh so we have P acting on P of + + align:start position:0% +x uh so we have P acting on P of + + + align:start position:0% +x uh so we have P acting on P of +X is equal to Lambda X + + align:start position:0% +X is equal to Lambda X + + + align:start position:0% +X is equal to Lambda X +and on the left hand side PX is going to + + align:start position:0% +and on the left hand side PX is going to + + + align:start position:0% +and on the left hand side PX is going to +give me Lambda X PX again will give me + + align:start position:0% +give me Lambda X PX again will give me + + + align:start position:0% +give me Lambda X PX again will give me +Lambda X and so we get Lambda 2 + + align:start position:0% +Lambda X and so we get Lambda 2 + + + align:start position:0% +Lambda X and so we get Lambda 2 +x equals Lambda + + align:start position:0% +x equals Lambda + + + align:start position:0% +x equals Lambda +X and if I bring everything to the left + + align:start position:0% +X and if I bring everything to the left + + + align:start position:0% +X and if I bring everything to the left +hand side I get Lambda * Lambda minus + + align:start position:0% +hand side I get Lambda * Lambda minus + + + align:start position:0% +hand side I get Lambda * Lambda minus +one xal 0 and because X is not a zero + + align:start position:0% +one xal 0 and because X is not a zero + + + align:start position:0% +one xal 0 and because X is not a zero +Vector what that means is Lambda has to + + align:start position:0% +Vector what that means is Lambda has to + + + align:start position:0% +Vector what that means is Lambda has to +be either zero or one so this is just a + + align:start position:0% +be either zero or one so this is just a + + + align:start position:0% +be either zero or one so this is just a +quick proof that uh the a value of a + + align:start position:0% +quick proof that uh the a value of a + + + align:start position:0% +quick proof that uh the a value of a +project Matrix is either Z or one so we + + align:start position:0% +project Matrix is either Z or one so we + + + align:start position:0% +project Matrix is either Z or one so we +already know that P is going to have Aug + + align:start position:0% +already know that P is going to have Aug + + + align:start position:0% +already know that P is going to have Aug +a values of0 or + + align:start position:0% +a values of0 or + + + align:start position:0% +a values of0 or +one now specifically how do identify + + align:start position:0% +one now specifically how do identify + + + align:start position:0% +one now specifically how do identify +which a vectors uh correspond to zero + + align:start position:0% +which a vectors uh correspond to zero + + + align:start position:0% +which a vectors uh correspond to zero +and which a vectors correspond to one + + align:start position:0% +and which a vectors correspond to one + + + align:start position:0% +and which a vectors correspond to one +well in this case P has a specific form + + align:start position:0% +well in this case P has a specific form + + + align:start position:0% +well in this case P has a specific form +which is a * a transpose divid a + + align:start position:0% +which is a * a transpose divid a + + + align:start position:0% +which is a * a transpose divid a +transpose + + align:start position:0% + + + + align:start position:0% + +a so I'll just write out uh explicitly + + align:start position:0% +a so I'll just write out uh explicitly + + + align:start position:0% +a so I'll just write out uh explicitly +what this is so h transpose + + align:start position:0% +what this is so h transpose + + + align:start position:0% +what this is so h transpose +a 1 / a transpose a is going to be 9 + + + align:start position:0% +a 1 / a transpose a is going to be 9 + + + + align:start position:0% +a 1 / a transpose a is going to be 9 + +16 on the denominator then we're going + + align:start position:0% +16 on the denominator then we're going + + + align:start position:0% +16 on the denominator then we're going +to have three and + + align:start position:0% + + + + align:start position:0% + +four and three and + + align:start position:0% +four and three and + + + align:start position:0% +four and three and +four now when we have a matrix of this + + align:start position:0% +four now when we have a matrix of this + + + align:start position:0% +four now when we have a matrix of this +form it's always going to be the case + + align:start position:0% +form it's always going to be the case + + + align:start position:0% +form it's always going to be the case +that the vector a is going to be an igen + + align:start position:0% +that the vector a is going to be an igen + + + align:start position:0% +that the vector a is going to be an igen +Vector with igen value one + + align:start position:0% + + + + align:start position:0% + +so let's + + align:start position:0% + + + + align:start position:0% + +check what is p acting on + + align:start position:0% +check what is p acting on + + + align:start position:0% +check what is p acting on +a well we end up + + align:start position:0% +a well we end up + + + align:start position:0% +a well we end up +with the Matrix p is 1 over + + align:start position:0% +with the Matrix p is 1 over + + + align:start position:0% +with the Matrix p is 1 over +25 3 + + align:start position:0% +25 3 + + + align:start position:0% +25 3 +4 3 + + align:start position:0% +4 3 + + + align:start position:0% +4 3 +4 this is the Matrix + + align:start position:0% +4 this is the Matrix + + + align:start position:0% +4 this is the Matrix +p and if we acted on the vector + + align:start position:0% + + + + align:start position:0% + +34 notice how this piece right here we + + align:start position:0% +34 notice how this piece right here we + + + align:start position:0% +34 notice how this piece right here we +can multiply out this is going to be a + + align:start position:0% +can multiply out this is going to be a + + + align:start position:0% +can multiply out this is going to be a +transpose and this is going to be a and + + align:start position:0% +transpose and this is going to be a and + + + align:start position:0% +transpose and this is going to be a and +if we multiply these two pieces out we + + align:start position:0% +if we multiply these two pieces out we + + + align:start position:0% +if we multiply these two pieces out we +get one we get + + align:start position:0% +get one we get + + + align:start position:0% +get one we get +25 which is exactly the denominator a + + align:start position:0% +25 which is exactly the denominator a + + + align:start position:0% +25 which is exactly the denominator a +transpose + + align:start position:0% +transpose + + + align:start position:0% +transpose +a so at the end of the day we get + + align:start position:0% +a so at the end of the day we get + + + align:start position:0% +a so at the end of the day we get +34 because the 25 divides out with the + + align:start position:0% +34 because the 25 divides out with the + + + align:start position:0% +34 because the 25 divides out with the +25 now note that this is exactly what we + + align:start position:0% +25 now note that this is exactly what we + + + align:start position:0% +25 now note that this is exactly what we +started with this is exactly + + align:start position:0% +started with this is exactly + + + align:start position:0% +started with this is exactly +a so note here that the vector a + + align:start position:0% +a so note here that the vector a + + + align:start position:0% +a so note here that the vector a +uh corresponds to an igen value of + + align:start position:0% + + + + align:start position:0% + +one + + align:start position:0% +one + + + align:start position:0% +one +meanwhile for an IG + + align:start position:0% + + + + align:start position:0% + +value of + + align:start position:0% +value of + + + align:start position:0% +value of +zero well it it always turns out to be + + align:start position:0% +zero well it it always turns out to be + + + align:start position:0% +zero well it it always turns out to be +the case that if I take any Vector + + align:start position:0% +the case that if I take any Vector + + + align:start position:0% +the case that if I take any Vector +perpendicular to a p acting on that + + align:start position:0% +perpendicular to a p acting on that + + + align:start position:0% +perpendicular to a p acting on that +Vector is going to be + + align:start position:0% +Vector is going to be + + + align:start position:0% +Vector is going to be +zero so what's a vector which I'll call + + align:start position:0% +zero so what's a vector which I'll call + + + align:start position:0% +zero so what's a vector which I'll call +B that's perpendicular to a well note + + align:start position:0% +B that's perpendicular to a well note + + + align:start position:0% +B that's perpendicular to a well note +that a is just a 2 x two Vector so that + + align:start position:0% +that a is just a 2 x two Vector so that + + + align:start position:0% +that a is just a 2 x two Vector so that +means there's only going to be One + + align:start position:0% +means there's only going to be One + + + align:start position:0% +means there's only going to be One +Direction that's perpendicular to a now + + align:start position:0% +Direction that's perpendicular to a now + + + align:start position:0% +Direction that's perpendicular to a now +just by eyeballing it I can see that a + + align:start position:0% +just by eyeballing it I can see that a + + + align:start position:0% +just by eyeballing it I can see that a +vector that's going to be perpendicular + + align:start position:0% +vector that's going to be perpendicular + + + align:start position:0% +vector that's going to be perpendicular +to a is four and + + align:start position:0% + + + + align:start position:0% + +three so let's quickly check that this + + align:start position:0% +three so let's quickly check that this + + + align:start position:0% +three so let's quickly check that this +is an I uh I Vector of p with I value + + align:start position:0% +is an I uh I Vector of p with I value + + + align:start position:0% +is an I uh I Vector of p with I value +zero so what we need to show is that P + + align:start position:0% +zero so what we need to show is that P + + + align:start position:0% +zero so what we need to show is that P +acting on this Vector B is + + align:start position:0% +acting on this Vector B is + + + align:start position:0% +acting on this Vector B is +zero so P acting on B + + align:start position:0% +zero so P acting on B + + + align:start position:0% +zero so P acting on B +is going to be 1 over + + align:start position:0% +is going to be 1 over + + + align:start position:0% +is going to be 1 over +25 it's going to be + + align:start position:0% +25 it's going to be + + + align:start position:0% +25 it's going to be + + align:start position:0% + + + + align:start position:0% + +34 multiplied by + + align:start position:0% + + + + align:start position:0% + +43 and note how when I multiply + + align:start position:0% +43 and note how when I multiply + + + align:start position:0% +43 and note how when I multiply +out this row on this column I get -3 * 4 + + align:start position:0% +out this row on this column I get -3 * 4 + + + align:start position:0% +out this row on this column I get -3 * 4 ++ 3 * 4 which is is going to be + + align:start position:0% ++ 3 * 4 which is is going to be + + + align:start position:0% ++ 3 * 4 which is is going to be +zero okay so this shows that this Vector + + align:start position:0% +zero okay so this shows that this Vector + + + align:start position:0% +zero okay so this shows that this Vector +B has an igen value of zero because note + + align:start position:0% +B has an igen value of zero because note + + + align:start position:0% +B has an igen value of zero because note +that we can write this as z + + align:start position:0% + + + + align:start position:0% + +b okay for the second part + + align:start position:0% + + + + align:start position:0% + +Q uh what are the igen vectors and I + + align:start position:0% +Q uh what are the igen vectors and I + + + align:start position:0% +Q uh what are the igen vectors and I +values of this Matrix + + align:start position:0% +values of this Matrix + + + align:start position:0% +values of this Matrix +Q well Q uh is a rotation Matrix so I'll + + align:start position:0% +Q well Q uh is a rotation Matrix so I'll + + + align:start position:0% +Q well Q uh is a rotation Matrix so I'll +just write out Q + + align:start position:0% +just write out Q + + + align:start position:0% +just write out Q +again + + align:start position:0% + + + + align:start position:0% + +6.88 + + align:start position:0% +6.88 + + + align:start position:0% +6.88 +6 so note that we can identify uh the + + align:start position:0% +6 so note that we can identify uh the + + + align:start position:0% +6 so note that we can identify uh the +the diagonal elements with a cosine uh + + align:start position:0% +the diagonal elements with a cosine uh + + + align:start position:0% +the diagonal elements with a cosine uh +of some angle Theta and we can associate + + align:start position:0% +of some angle Theta and we can associate + + + align:start position:0% +of some angle Theta and we can associate +the off diagonal Parts as uh sin Theta + + align:start position:0% +the off diagonal Parts as uh sin Theta + + + align:start position:0% +the off diagonal Parts as uh sin Theta +and negative sin Theta and the reason we + + align:start position:0% +and negative sin Theta and the reason we + + + align:start position:0% +and negative sin Theta and the reason we +can do that is because 6^ 2+ 8^ 2 is 1 + + align:start position:0% +can do that is because 6^ 2+ 8^ 2 is 1 + + + align:start position:0% +can do that is because 6^ 2+ 8^ 2 is 1 +so this is a rotation + + align:start position:0% +so this is a rotation + + + align:start position:0% +so this is a rotation +Matrix now uh to work out the a values I + + align:start position:0% +Matrix now uh to work out the a values I + + + align:start position:0% +Matrix now uh to work out the a values I +take a look at the characteristic + + align:start position:0% +take a look at the characteristic + + + align:start position:0% +take a look at the characteristic +equation so this is going to give me if + + align:start position:0% +equation so this is going to give me if + + + align:start position:0% +equation so this is going to give me if +I take a look at the characteristic + + align:start position:0% +I take a look at the characteristic + + + align:start position:0% +I take a look at the characteristic +equation it's going to be 6 minus + + align:start position:0% +equation it's going to be 6 minus + + + align:start position:0% +equation it's going to be 6 minus +Lambda + + align:start position:0% +Lambda + + + align:start position:0% +Lambda +squared then we have minus * 8 * .8 so + + align:start position:0% +squared then we have minus * 8 * .8 so + + + align:start position:0% +squared then we have minus * 8 * .8 so +that's going to be + + align:start position:0% +that's going to be + + + align:start position:0% +that's going to be +plus 8^ + + align:start position:0% +plus 8^ + + + align:start position:0% +plus 8^ +SAR and we want this to be zero + + align:start position:0% + + + + align:start position:0% + +so if I rewrite this I get Lambda is 6 + + align:start position:0% +so if I rewrite this I get Lambda is 6 + + + align:start position:0% +so if I rewrite this I get Lambda is 6 +Plus or + + align:start position:0% +Plus or + + + align:start position:0% +Plus or +minus8 I where I is the imaginary number + + align:start position:0% +minus8 I where I is the imaginary number + + + align:start position:0% +minus8 I where I is the imaginary number +so notice how the igen values come in + + align:start position:0% +so notice how the igen values come in + + + align:start position:0% +so notice how the igen values come in +complex conjugate Pairs and this is + + align:start position:0% +complex conjugate Pairs and this is + + + align:start position:0% +complex conjugate Pairs and this is +always the case when we have a real + + align:start position:0% +always the case when we have a real + + + align:start position:0% +always the case when we have a real +Matrix so we can uh we can find first + + align:start position:0% +Matrix so we can uh we can find first + + + align:start position:0% +Matrix so we can uh we can find first +off just the igen value that corresponds + + align:start position:0% +off just the igen value that corresponds + + + align:start position:0% +off just the igen value that corresponds +to 6 +8 I and then at the end we'll be + + align:start position:0% +to 6 +8 I and then at the end we'll be + + + align:start position:0% +to 6 +8 I and then at the end we'll be +able to find the second igen vector by + + align:start position:0% +able to find the second igen vector by + + + align:start position:0% +able to find the second igen vector by +just taking the complex conjugate of the + + align:start position:0% +just taking the complex conjugate of the + + + align:start position:0% +just taking the complex conjugate of the +first + + align:start position:0% +first + + + align:start position:0% +first +one so let's compute Q minus Lambda + + align:start position:0% + + + + align:start position:0% + +I and if we have this acting on some + + align:start position:0% +I and if we have this acting on some + + + align:start position:0% +I and if we have this acting on some +igen Vector U we want this to be + + align:start position:0% +igen Vector U we want this to be + + + align:start position:0% +igen Vector U we want this to be +zero now Q minus Lambda I is going to be + + align:start position:0% +zero now Q minus Lambda I is going to be + + + align:start position:0% +zero now Q minus Lambda I is going to be +for the case Lambda is 6 +8 + + align:start position:0% +for the case Lambda is 6 +8 + + + align:start position:0% +for the case Lambda is 6 +8 +I this is going to give me a quantity + + align:start position:0% +I this is going to give me a quantity + + + align:start position:0% +I this is going to give me a quantity +of minus 8 + + align:start position:0% +of minus 8 + + + align:start position:0% +of minus 8 +I minus + + align:start position:0% + + + + align:start position:0% + +88 and minus8 + + align:start position:0% +88 and minus8 + + + align:start position:0% +88 and minus8 +I and I'm going to write down components + + align:start position:0% +I and I'm going to write down components + + + align:start position:0% +I and I'm going to write down components +of U which are U1 and + + align:start position:0% +of U which are U1 and + + + align:start position:0% +of U which are U1 and +U2 and we want this to + + align:start position:0% +U2 and we want this to + + + align:start position:0% +U2 and we want this to +vanish and we note that the second row + + align:start position:0% +vanish and we note that the second row + + + align:start position:0% +vanish and we note that the second row +is a constant multiple of the first row + + align:start position:0% +is a constant multiple of the first row + + + align:start position:0% +is a constant multiple of the first row +specifically If I multiply this first + + align:start position:0% +specifically If I multiply this first + + + align:start position:0% +specifically If I multiply this first +row through by I we would get Negative + + align:start position:0% +row through by I we would get Negative + + + align:start position:0% +row through by I we would get Negative +i^2 which is just one + + align:start position:0% +i^2 which is just one + + + align:start position:0% +i^2 which is just one +and then the second part would be + + align:start position:0% +and then the second part would be + + + align:start position:0% +and then the second part would be +negative I so we would just get the + + align:start position:0% +negative I so we would just get the + + + align:start position:0% +negative I so we would just get the +second row back which is + + align:start position:0% + + + + align:start position:0% + +good so we just need to find U1 U2 that + + align:start position:0% +good so we just need to find U1 U2 that + + + align:start position:0% +good so we just need to find U1 U2 that +are orthogonal to this first this first + + align:start position:0% +are orthogonal to this first this first + + + align:start position:0% +are orthogonal to this first this first +row and again just by inspection I can + + align:start position:0% +row and again just by inspection I can + + + align:start position:0% +row and again just by inspection I can +pick one and negative + + align:start position:0% +pick one and negative + + + align:start position:0% +pick one and negative +I so note that uh that would give mega8 + + align:start position:0% +I so note that uh that would give mega8 + + + align:start position:0% +I so note that uh that would give mega8 +I Plus 8 I and this vanishes so this is + + align:start position:0% +I Plus 8 I and this vanishes so this is + + + align:start position:0% +I Plus 8 I and this vanishes so this is +one uh this is the a that corresponds to + + align:start position:0% +one uh this is the a that corresponds to + + + align:start position:0% +one uh this is the a that corresponds to +the value Lambda 6 +8 + + align:start position:0% + + + + align:start position:0% + +I uh in the + + align:start position:0% +I uh in the + + + align:start position:0% +I uh in the +meantime if I take the + + align:start position:0% +meantime if I take the + + + align:start position:0% +meantime if I take the +second I value which is negative point8 + + align:start position:0% + + + + align:start position:0% + +I I can take U which is just the complex + + align:start position:0% +I I can take U which is just the complex + + + align:start position:0% +I I can take U which is just the complex +conjugate of this U up + + align:start position:0% +conjugate of this U up + + + align:start position:0% +conjugate of this U up +here so it'll be 1 plus + + align:start position:0% +here so it'll be 1 plus + + + align:start position:0% +here so it'll be 1 plus +I so this concludes the aen values uh an + + align:start position:0% +I so this concludes the aen values uh an + + + align:start position:0% +I so this concludes the aen values uh an +aen vectors of this Matrix + + align:start position:0% + + + + align:start position:0% + +Q okay now lastly number three we're + + align:start position:0% +Q okay now lastly number three we're + + + align:start position:0% +Q okay now lastly number three we're +looking at uh a rotation + + align:start position:0% +looking at uh a rotation + + + align:start position:0% +looking at uh a rotation +Matrix uh sorry not a rotation Matrix + + align:start position:0% +Matrix uh sorry not a rotation Matrix + + + align:start position:0% +Matrix uh sorry not a rotation Matrix +but a reflection Matrix which has the + + align:start position:0% +but a reflection Matrix which has the + + + align:start position:0% +but a reflection Matrix which has the +form 2 p minus + + align:start position:0% +form 2 p minus + + + align:start position:0% +form 2 p minus +I where p is the same Matrix uh that we + + align:start position:0% +I where p is the same Matrix uh that we + + + align:start position:0% +I where p is the same Matrix uh that we +had in part + + align:start position:0% +had in part + + + align:start position:0% +had in part +one now it at first glance it looks like + + align:start position:0% +one now it at first glance it looks like + + + align:start position:0% +one now it at first glance it looks like +we might have to diag Alize this entire + + align:start position:0% +we might have to diag Alize this entire + + + align:start position:0% +we might have to diag Alize this entire +Matrix however note that by shifting uh + + align:start position:0% +Matrix however note that by shifting uh + + + align:start position:0% +Matrix however note that by shifting uh +2 p by I uh we only shift the a values + + align:start position:0% +2 p by I uh we only shift the a values + + + align:start position:0% +2 p by I uh we only shift the a values +and we don't actually change the aen + + align:start position:0% +and we don't actually change the aen + + + align:start position:0% +and we don't actually change the aen +vectors so note that this Matrix R which + + align:start position:0% +vectors so note that this Matrix R which + + + align:start position:0% +vectors so note that this Matrix R which +is 2 p minus I it's going to have the + + align:start position:0% +is 2 p minus I it's going to have the + + + align:start position:0% +is 2 p minus I it's going to have the +same igen vectors as P it's just going + + align:start position:0% +same igen vectors as P it's just going + + + align:start position:0% +same igen vectors as P it's just going +to have different igen + + align:start position:0% +to have different igen + + + align:start position:0% +to have different igen +values so first off we're going to have + + align:start position:0% +values so first off we're going to have + + + align:start position:0% +values so first off we're going to have +uh one IG + + align:start position:0% +uh one IG + + + align:start position:0% +uh one IG +Vector uh so the first igen Vector is + + align:start position:0% +Vector uh so the first igen Vector is + + + align:start position:0% +Vector uh so the first igen Vector is +going to be a so we have one igen vector + + align:start position:0% +going to be a so we have one igen vector + + + align:start position:0% +going to be a so we have one igen vector +which is + + align:start position:0% +which is + + + align:start position:0% +which is +a so we have one igen + + align:start position:0% + + + + align:start position:0% + +vector which is + + align:start position:0% +vector which is + + + align:start position:0% +vector which is +a and note that when for the vector + + align:start position:0% +a and note that when for the vector + + + align:start position:0% +a and note that when for the vector +a uh it corresponds to the igen value of + + align:start position:0% +a uh it corresponds to the igen value of + + + align:start position:0% +a uh it corresponds to the igen value of +one so what igen value does this + + align:start position:0% +one so what igen value does this + + + align:start position:0% +one so what igen value does this +correspond + + align:start position:0% +correspond + + + align:start position:0% +correspond +to this is going to give me a + + align:start position:0% +to this is going to give me a + + + align:start position:0% +to this is going to give me a +Lambda which is 2 * 1 + + align:start position:0% +Lambda which is 2 * 1 + + + align:start position:0% +Lambda which is 2 * 1 +minus one so it's one so note that a the + + align:start position:0% +minus one so it's one so note that a the + + + align:start position:0% +minus one so it's one so note that a the +vector a not only has an Igan value of + + align:start position:0% +vector a not only has an Igan value of + + + align:start position:0% +vector a not only has an Igan value of +one for p but it has an a value of one + + align:start position:0% +one for p but it has an a value of one + + + align:start position:0% +one for p but it has an a value of one +for r as + + align:start position:0% +for r as + + + align:start position:0% +for r as +well the second + + align:start position:0% + + + + align:start position:0% + +case was + + align:start position:0% +case was + + + align:start position:0% +case was +B and remember that B has an igen value + + align:start position:0% +B and remember that B has an igen value + + + align:start position:0% +B and remember that B has an igen value +of zero for p so when we act our acting + + align:start position:0% +of zero for p so when we act our acting + + + align:start position:0% +of zero for p so when we act our acting +on + + align:start position:0% + + + + align:start position:0% + +B we have 2 * 0 minus 1 B so this is + + align:start position:0% +B we have 2 * 0 minus 1 B so this is + + + align:start position:0% +B we have 2 * 0 minus 1 B so this is +going to give us negative + + align:start position:0% +going to give us negative + + + align:start position:0% +going to give us negative +B so the igen value for B is going to be + + align:start position:0% +B so the igen value for B is going to be + + + align:start position:0% +B so the igen value for B is going to be +negative + + align:start position:0% + + + + align:start position:0% + +1 okay and this is actually a general uh + + align:start position:0% +1 okay and this is actually a general uh + + + align:start position:0% +1 okay and this is actually a general uh +case for uh reflection matrices is that + + align:start position:0% +case for uh reflection matrices is that + + + align:start position:0% +case for uh reflection matrices is that +they typically have I values of plus one + + align:start position:0% +they typically have I values of plus one + + + align:start position:0% +they typically have I values of plus one +or negative + + align:start position:0% +or negative + + + align:start position:0% +or negative +one Okay so we've just taken a look at + + align:start position:0% +one Okay so we've just taken a look at + + + align:start position:0% +one Okay so we've just taken a look at +uh several matrices that come up in + + align:start position:0% +uh several matrices that come up in + + + align:start position:0% +uh several matrices that come up in +practice uh We've looked at projection + + align:start position:0% +practice uh We've looked at projection + + + align:start position:0% +practice uh We've looked at projection +matrices reflection matrices and + + align:start position:0% +matrices reflection matrices and + + + align:start position:0% +matrices reflection matrices and +rotation matrices and we've uh seen a + + align:start position:0% +rotation matrices and we've uh seen a + + + align:start position:0% +rotation matrices and we've uh seen a +little bit of the properties of their + + align:start position:0% +little bit of the properties of their + + + align:start position:0% +little bit of the properties of their +igen values and igen vectors so I'll uh + + align:start position:0% +igen values and igen vectors so I'll uh + + + align:start position:0% +igen values and igen vectors so I'll uh +just conclude here and uh good luck on + + align:start position:0% +just conclude here and uh good luck on + + + align:start position:0% +just conclude here and uh good luck on +your test \ No newline at end of file diff --git a/EjXtpzysDL4.txt b/EjXtpzysDL4.txt new file mode 100644 index 0000000000000000000000000000000000000000..70be8b44a3578d0590a408269c77c7f04b44ba67 --- /dev/null +++ b/EjXtpzysDL4.txt @@ -0,0 +1,11072 @@ +align:start position:0% + +Okay. So, uh let me just recall first + + align:start position:0% +Okay. So, uh let me just recall first + + + align:start position:0% +Okay. So, uh let me just recall first +that + + align:start position:0% +that + + + align:start position:0% +that +so what we were talking about so this is + + align:start position:0% +so what we were talking about so this is + + + align:start position:0% +so what we were talking about so this is +a very important concept uh of a + + align:start position:0% +a very important concept uh of a + + + align:start position:0% +a very important concept uh of a +sequence concept of a sequence. + + align:start position:0% +sequence concept of a sequence. + + + align:start position:0% +sequence concept of a sequence. +So sequence is is the formal definition + + align:start position:0% +So sequence is is the formal definition + + + align:start position:0% +So sequence is is the formal definition +is that you have a map from the natural + + align:start position:0% +is that you have a map from the natural + + + align:start position:0% +is that you have a map from the natural +number into R + + align:start position:0% +number into R + + + align:start position:0% +number into R +and then we denote so then the image of + + align:start position:0% +and then we denote so then the image of + + + align:start position:0% +and then we denote so then the image of +a particular natural number n it's + + align:start position:0% +a particular natural number n it's + + + align:start position:0% +a particular natural number n it's +usually denoted like a n like this you + + align:start position:0% +usually denoted like a n like this you + + + align:start position:0% +usually denoted like a n like this you +know it could be some other instead of a + + align:start position:0% +know it could be some other instead of a + + + align:start position:0% +know it could be some other instead of a +it could be bn potentially it could be + + align:start position:0% +it could be bn potentially it could be + + + align:start position:0% +it could be bn potentially it could be +another subscript but it's this is like + + align:start position:0% +another subscript but it's this is like + + + align:start position:0% +another subscript but it's this is like +the most common thing to denote it like + + align:start position:0% +the most common thing to denote it like + + + align:start position:0% +the most common thing to denote it like +this instead of like but it really is a + + align:start position:0% +this instead of like but it really is a + + + align:start position:0% +this instead of like but it really is a +function. Okay, so that's a sequence a + + align:start position:0% +function. Okay, so that's a sequence a + + + align:start position:0% +function. Okay, so that's a sequence a +subsequence. + + align:start position:0% + + + + align:start position:0% + +So subsequence is that you have a + + align:start position:0% +So subsequence is that you have a + + + align:start position:0% +So subsequence is that you have a +sequence and then you have another map + + align:start position:0% +sequence and then you have another map + + + align:start position:0% +sequence and then you have another map +but this map is not just any map from + + align:start position:0% +but this map is not just any map from + + + align:start position:0% +but this map is not just any map from +the integers to the integers. It has to + + align:start position:0% +the integers to the integers. It has to + + + align:start position:0% +the integers to the integers. It has to +be strictly increasing. + + align:start position:0% + + + + align:start position:0% + +And why does it have to be strictly + + align:start position:0% +And why does it have to be strictly + + + align:start position:0% +And why does it have to be strictly +increasing? Because we want for the + + align:start position:0% +increasing? Because we want for the + + + align:start position:0% +increasing? Because we want for the +subsequence. If you think about the + + align:start position:0% +subsequence. If you think about the + + + align:start position:0% +subsequence. If you think about the +numbers that come out when you plug in a + + align:start position:0% +numbers that come out when you plug in a + + + align:start position:0% +numbers that come out when you plug in a +when you're looking at the a then you + + align:start position:0% +when you're looking at the a then you + + + align:start position:0% +when you're looking at the a then you +want + + align:start position:0% +want + + + align:start position:0% +want +some of those numbers to be in the + + align:start position:0% +some of those numbers to be in the + + + align:start position:0% +some of those numbers to be in the +subsequence, but you want the ordering + + align:start position:0% +subsequence, but you want the ordering + + + align:start position:0% +subsequence, but you want the ordering +to be the same. So this map so that's + + align:start position:0% +to be the same. So this map so that's + + + align:start position:0% +to be the same. So this map so that's +why this map has to be strictly + + align:start position:0% +why this map has to be strictly + + + align:start position:0% +why this map has to be strictly +increasing right can't sort of I mean + + align:start position:0% +increasing right can't sort of I mean + + + align:start position:0% +increasing right can't sort of I mean +you and you can't pick the several + + align:start position:0% +you and you can't pick the several + + + align:start position:0% +you and you can't pick the several +elements many times if it wasn't picked + + align:start position:0% +elements many times if it wasn't picked + + + align:start position:0% +elements many times if it wasn't picked +many times in the original uh sequence + + align:start position:0% +many times in the original uh sequence + + + align:start position:0% +many times in the original uh sequence +right + + align:start position:0% +right + + + align:start position:0% +right +so this is so a subsequence is where you + + align:start position:0% +so this is so a subsequence is where you + + + align:start position:0% +so this is so a subsequence is where you +have another map from the natural number + + align:start position:0% +have another map from the natural number + + + align:start position:0% +have another map from the natural number +to the natural number that is strictly + + align:start position:0% +to the natural number that is strictly + + + align:start position:0% +to the natural number that is strictly +increasing and then you're looking at + + align:start position:0% +increasing and then you're looking at + + + align:start position:0% +increasing and then you're looking at +the composition of these two maps so + + align:start position:0% +the composition of these two maps so + + + align:start position:0% +the composition of these two maps so +you're looking at sorry uh this thing + + align:start position:0% +you're looking at sorry uh this thing + + + align:start position:0% +you're looking at sorry uh this thing +here + + align:start position:0% +here + + + align:start position:0% +here +right and you call this here and then + + align:start position:0% +right and you call this here and then + + + align:start position:0% +right and you call this here and then +that's usually + + align:start position:0% +that's usually + + + align:start position:0% +that's usually +denoted something + + align:start position:0% +denoted something + + + align:start position:0% +denoted something +like this a n k a n is the original + + align:start position:0% +like this a n k a n is the original + + + align:start position:0% +like this a n k a n is the original +sequence k means that it's really that + + align:start position:0% +sequence k means that it's really that + + + align:start position:0% +sequence k means that it's really that +you take the image of k under this + + align:start position:0% +you take the image of k under this + + + align:start position:0% +you take the image of k under this +strictly increasing map and then you're + + align:start position:0% +strictly increasing map and then you're + + + align:start position:0% +strictly increasing map and then you're +looking at the element in the sequence + + align:start position:0% +looking at the element in the sequence + + + align:start position:0% +looking at the element in the sequence +right so it's sort of n k is really you + + align:start position:0% +right so it's sort of n k is really you + + + align:start position:0% +right so it's sort of n k is really you +should think about it as G of K. + + align:start position:0% +should think about it as G of K. + + + align:start position:0% +should think about it as G of K. +Okay, so that's that's what a a a + + align:start position:0% +Okay, so that's that's what a a a + + + align:start position:0% +Okay, so that's that's what a a a +subsequence is. And again, it's + + align:start position:0% +subsequence is. And again, it's + + + align:start position:0% +subsequence is. And again, it's +important that it's strictly increasing + + align:start position:0% +important that it's strictly increasing + + + align:start position:0% +important that it's strictly increasing +because you want the elements to be in + + align:start position:0% +because you want the elements to be in + + + align:start position:0% +because you want the elements to be in +the same order than it was in the + + align:start position:0% +the same order than it was in the + + + align:start position:0% +the same order than it was in the +original sequence. And you don't want + + align:start position:0% +original sequence. And you don't want + + + align:start position:0% +original sequence. And you don't want +things you don't even want things to be + + align:start position:0% +things you don't even want things to be + + + align:start position:0% +things you don't even want things to be +picked more times than it was in + + align:start position:0% +picked more times than it was in + + + align:start position:0% +picked more times than it was in +original sequence. Mhm. So that that's + + align:start position:0% +original sequence. Mhm. So that that's + + + align:start position:0% +original sequence. Mhm. So that that's +that's you know so this this whole + + align:start position:0% +that's you know so this this whole + + + align:start position:0% +that's you know so this this whole +concept of a sequence of subunits is + + align:start position:0% +concept of a sequence of subunits is + + + align:start position:0% +concept of a sequence of subunits is +really important. Then + + align:start position:0% +really important. Then + + + align:start position:0% +really important. Then +the next really important concept is + + align:start position:0% +the next really important concept is + + + align:start position:0% +the next really important concept is +uh is of convergence. + + align:start position:0% +uh is of convergence. + + + align:start position:0% +uh is of convergence. +So if you have a sequence a n then you + + align:start position:0% +So if you have a sequence a n then you + + + align:start position:0% +So if you have a sequence a n then you +say that is converging to a. So so a is + + align:start position:0% +say that is converging to a. So so a is + + + align:start position:0% +say that is converging to a. So so a is +another real number. It's not infinity. + + align:start position:0% +another real number. It's not infinity. + + + align:start position:0% +another real number. It's not infinity. +is another real number and so a n + + align:start position:0% +is another real number and so a n + + + align:start position:0% +is another real number and so a n +converts. So a n converts + + align:start position:0% + + + + align:start position:0% + +to a if for all + + align:start position:0% +to a if for all + + + align:start position:0% +to a if for all +epsilon greater than zero there exist + + align:start position:0% + + + + align:start position:0% + +n an integer n you know by capital n + + align:start position:0% +n an integer n you know by capital n + + + align:start position:0% +n an integer n you know by capital n +such that if little n is bigger equal to + + align:start position:0% +such that if little n is bigger equal to + + + align:start position:0% +such that if little n is bigger equal to +this capital n then a n minus minus a + + align:start position:0% +this capital n then a n minus minus a + + + align:start position:0% +this capital n then a n minus minus a +have to be less than epsilon. Right? of + + align:start position:0% +have to be less than epsilon. Right? of + + + align:start position:0% +have to be less than epsilon. Right? of +those. So if you are sufficiently far + + align:start position:0% +those. So if you are sufficiently far + + + align:start position:0% +those. So if you are sufficiently far +out in sequence then everything in that + + align:start position:0% +out in sequence then everything in that + + + align:start position:0% +out in sequence then everything in that +sequence is bunch epsilon close to a + + align:start position:0% +sequence is bunch epsilon close to a + + + align:start position:0% +sequence is bunch epsilon close to a +okay that's what it's saying + + align:start position:0% +okay that's what it's saying + + + align:start position:0% +okay that's what it's saying +and so as if you have a sequence + + align:start position:0% +and so as if you have a sequence + + + align:start position:0% +and so as if you have a sequence +so a sequence + + align:start position:0% + + + + align:start position:0% + +that + + align:start position:0% +that + + + align:start position:0% +that +is not convergent + + align:start position:0% + + + + align:start position:0% + +uh is set to be divergent. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +Um and the next thing for sequences is + + align:start position:0% +Um and the next thing for sequences is + + + align:start position:0% +Um and the next thing for sequences is +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +I'm just briefly reviewing this from + + align:start position:0% +I'm just briefly reviewing this from + + + align:start position:0% +I'm just briefly reviewing this from +last time. The next thing for sequences + + align:start position:0% +last time. The next thing for sequences + + + align:start position:0% +last time. The next thing for sequences +are the are the break + + align:start position:0% + + + + align:start position:0% + +to break uh + + align:start position:0% +to break uh + + + align:start position:0% +to break uh +uh laws or whatever you want to call + + align:start position:0% +uh laws or whatever you want to call + + + align:start position:0% +uh laws or whatever you want to call +them. + + align:start position:0% + + + + align:start position:0% + +And so that is that if you take a + + align:start position:0% +And so that is that if you take a + + + align:start position:0% +And so that is that if you take a +sequence, if you have a sequence a n and + + align:start position:0% +sequence, if you have a sequence a n and + + + align:start position:0% +sequence, if you have a sequence a n and +a n converts to a bn converts to b + + align:start position:0% + + + + align:start position:0% + +then if you form the sum of these two + + align:start position:0% +then if you form the sum of these two + + + align:start position:0% +then if you form the sum of these two +uh a + + align:start position:0% +uh a + + + align:start position:0% +uh a +n + bn. + + align:start position:0% +n + bn. + + + align:start position:0% +n + bn. +So this is a new sequence where the nth + + align:start position:0% +So this is a new sequence where the nth + + + align:start position:0% +So this is a new sequence where the nth +element is the sum of the nth element of + + align:start position:0% +element is the sum of the nth element of + + + align:start position:0% +element is the sum of the nth element of +the other two sequences. then this + + align:start position:0% +the other two sequences. then this + + + align:start position:0% +the other two sequences. then this +sequence here CN also converge and the + + align:start position:0% +sequence here CN also converge and the + + + align:start position:0% +sequence here CN also converge and the +limit here is the sum of the limits. + + align:start position:0% +limit here is the sum of the limits. + + + align:start position:0% +limit here is the sum of the limits. +Okay. And likewise if you take a if + + align:start position:0% +Okay. And likewise if you take a if + + + align:start position:0% +Okay. And likewise if you take a if +you're looking at at if you define a + + align:start position:0% +you're looking at at if you define a + + + align:start position:0% +you're looking at at if you define a +sequence so this was one + + align:start position:0% +sequence so this was one + + + align:start position:0% +sequence so this was one +two is that if you take a constant so + + align:start position:0% +two is that if you take a constant so + + + align:start position:0% +two is that if you take a constant so +this is a constant + + align:start position:0% +this is a constant + + + align:start position:0% +this is a constant +and you define cn to be c * a n then + + align:start position:0% +and you define cn to be c * a n then + + + align:start position:0% +and you define cn to be c * a n then +this cn also converge and the limit here + + align:start position:0% +this cn also converge and the limit here + + + align:start position:0% +this cn also converge and the limit here +is just c * a right that's the second + + align:start position:0% +is just c * a right that's the second + + + align:start position:0% +is just c * a right that's the second +one then uh this one I might have done + + align:start position:0% +one then uh this one I might have done + + + align:start position:0% +one then uh this one I might have done +it in the other order but there's no you + + align:start position:0% +it in the other order but there's no you + + + align:start position:0% +it in the other order but there's no you +know it's not you know there's no + + align:start position:0% +know it's not you know there's no + + + align:start position:0% +know it's not you know there's no +particular order + + align:start position:0% +particular order + + + align:start position:0% +particular order +um to have it in. + + align:start position:0% +um to have it in. + + + align:start position:0% +um to have it in. +Uh the third one is that if you are + + align:start position:0% +Uh the third one is that if you are + + + align:start position:0% +Uh the third one is that if you are +looking at the product. So if you define + + align:start position:0% +looking at the product. So if you define + + + align:start position:0% +looking at the product. So if you define +a sequence that is given by the product + + align:start position:0% +a sequence that is given by the product + + + align:start position:0% +a sequence that is given by the product +of the two then C and converge also and + + align:start position:0% +of the two then C and converge also and + + + align:start position:0% +of the two then C and converge also and +the limit is the product of the limits. + + align:start position:0% +the limit is the product of the limits. + + + align:start position:0% +the limit is the product of the limits. +And then the fourth rule is that if a n + + align:start position:0% +And then the fourth rule is that if a n + + + align:start position:0% +And then the fourth rule is that if a n +is not equal to zero for all n and the + + align:start position:0% +is not equal to zero for all n and the + + + align:start position:0% +is not equal to zero for all n and the +limit here + + align:start position:0% +limit here + + + align:start position:0% +limit here +is also not equal to zero. Then if + + align:start position:0% +is also not equal to zero. Then if + + + align:start position:0% +is also not equal to zero. Then if +you're looking at 1 / a n then those + + align:start position:0% +you're looking at 1 / a n then those + + + align:start position:0% +you're looking at 1 / a n then those +converge to one. + + align:start position:0% +converge to one. + + + align:start position:0% +converge to one. +Okay. So those are the four four the + + align:start position:0% +Okay. So those are the four four the + + + align:start position:0% +Okay. So those are the four four the +four roots. + + align:start position:0% +four roots. + + + align:start position:0% +four roots. +Just write it as four. And again, it's + + align:start position:0% +Just write it as four. And again, it's + + + align:start position:0% +Just write it as four. And again, it's +not like there's any particular + + align:start position:0% +not like there's any particular + + + align:start position:0% +not like there's any particular +convention with the ordering. And I + + align:start position:0% +convention with the ordering. And I + + + align:start position:0% +convention with the ordering. And I +think I might have done it. I might have + + align:start position:0% +think I might have done it. I might have + + + align:start position:0% +think I might have done it. I might have +exchanged the order of one and two last + + align:start position:0% +exchanged the order of one and two last + + + align:start position:0% +exchanged the order of one and two last +time. But + + align:start position:0% + + + + align:start position:0% + +okay. Um now, uh let's see an example of + + align:start position:0% +okay. Um now, uh let's see an example of + + + align:start position:0% +okay. Um now, uh let's see an example of +how that works. + + align:start position:0% +how that works. + + + align:start position:0% +how that works. +So let's define a sequence. + + align:start position:0% +So let's define a sequence. + + + align:start position:0% +So let's define a sequence. +Uh let's define a sequence uh n 2 + 1 n + + align:start position:0% +Uh let's define a sequence uh n 2 + 1 n + + + align:start position:0% +Uh let's define a sequence uh n 2 + 1 n +2 + uh n + + + align:start position:0% +2 + uh n + + + + align:start position:0% +2 + uh n + +uh + one. Let's look at this sequence + + align:start position:0% +uh + one. Let's look at this sequence + + + align:start position:0% +uh + one. Let's look at this sequence +here right for each n that give us uh + + align:start position:0% +here right for each n that give us uh + + + align:start position:0% +here right for each n that give us uh +actually a rational number but it's only + + align:start position:0% +actually a rational number but it's only + + + align:start position:0% +actually a rational number but it's only +real number. + + align:start position:0% +real number. + + + align:start position:0% +real number. +Now in order to understand this I can + + align:start position:0% +Now in order to understand this I can + + + align:start position:0% +Now in order to understand this I can +rewrite this one here as I can factor + + align:start position:0% +rewrite this one here as I can factor + + + align:start position:0% +rewrite this one here as I can factor +out 1 / n well I can factor out n squ + + align:start position:0% +out 1 / n well I can factor out n squ + + + align:start position:0% +out 1 / n well I can factor out n squ +here. So I can write it like this + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +like that. And then of course I can get + + align:start position:0% +like that. And then of course I can get + + + align:start position:0% +like that. And then of course I can get +rid of the n squ + + align:start position:0% +rid of the n squ + + + align:start position:0% +rid of the n squ +in both denominator and denominator. And + + align:start position:0% +in both denominator and denominator. And + + + align:start position:0% +in both denominator and denominator. And +now I can look so so this so you may as + + align:start position:0% +now I can look so so this so you may as + + + align:start position:0% +now I can look so so this so you may as +well think about the sequence as this + + align:start position:0% +well think about the sequence as this + + + align:start position:0% +well think about the sequence as this +thing here. So now if I defined um so + + align:start position:0% +thing here. So now if I defined um so + + + align:start position:0% +thing here. So now if I defined um so +now I can just look at say uh I can look + + align:start position:0% +now I can just look at say uh I can look + + + align:start position:0% +now I can just look at say uh I can look +at uh the sequence which is one I can + + align:start position:0% +at uh the sequence which is one I can + + + align:start position:0% +at uh the sequence which is one I can +just first look at the sequence which is + + align:start position:0% +just first look at the sequence which is + + + align:start position:0% +just first look at the sequence which is +1 / n. If I'm looking at this sequence + + align:start position:0% +1 / n. If I'm looking at this sequence + + + align:start position:0% +1 / n. If I'm looking at this sequence +here, right, one / n, this here converts + + align:start position:0% +here, right, one / n, this here converts + + + align:start position:0% +here, right, one / n, this here converts +to zero. This is essentially just + + align:start position:0% +to zero. This is essentially just + + + align:start position:0% +to zero. This is essentially just +followed from the ardian property, + + align:start position:0% +followed from the ardian property, + + + align:start position:0% +followed from the ardian property, +right? But we already we've already seen + + align:start position:0% +right? But we already we've already seen + + + align:start position:0% +right? But we already we've already seen +this that 1 / n converts to zero. + + align:start position:0% +this that 1 / n converts to zero. + + + align:start position:0% +this that 1 / n converts to zero. +And the same hold for 1 / n^2, right? + + align:start position:0% +And the same hold for 1 / n^2, right? + + + align:start position:0% +And the same hold for 1 / n^2, right? +This here also converts to zero, right? + + align:start position:0% +This here also converts to zero, right? + + + align:start position:0% +This here also converts to zero, right? +And so if you're looking at the + + align:start position:0% +And so if you're looking at the + + + align:start position:0% +And so if you're looking at the +sequence, you could even look at the + + align:start position:0% +sequence, you could even look at the + + + align:start position:0% +sequence, you could even look at the +sequence. + + align:start position:0% +sequence. + + + align:start position:0% +sequence. +Let's call this x n. This here is yn. + + align:start position:0% +Let's call this x n. This here is yn. + + + align:start position:0% +Let's call this x n. This here is yn. +I'm going to run out of character very + + align:start position:0% +I'm going to run out of character very + + + align:start position:0% +I'm going to run out of character very +quickly. Uh set n. This is just going to + + align:start position:0% +quickly. Uh set n. This is just going to + + + align:start position:0% +quickly. Uh set n. This is just going to +be the sequence which is constant one. + + align:start position:0% +be the sequence which is constant one. + + + align:start position:0% +be the sequence which is constant one. +Right? Well, if if it's constant one, + + align:start position:0% +Right? Well, if if it's constant one, + + + align:start position:0% +Right? Well, if if it's constant one, +then obviously it's converging to one, + + align:start position:0% +then obviously it's converging to one, + + + align:start position:0% +then obviously it's converging to one, +right? And so now I can just think about + + align:start position:0% +right? And so now I can just think about + + + align:start position:0% +right? And so now I can just think about +I can think about the sequence bn + + align:start position:0% +I can think about the sequence bn + + + align:start position:0% +I can think about the sequence bn +to be equal to x sorry equal to set + + align:start position:0% +to be equal to x sorry equal to set + + + align:start position:0% +to be equal to x sorry equal to set +plus uh y set n plus yn right this here + + align:start position:0% +plus uh y set n plus yn right this here + + + align:start position:0% +plus uh y set n plus yn right this here +is a sequence here is what yn is here's + + align:start position:0% +is a sequence here is what yn is here's + + + align:start position:0% +is a sequence here is what yn is here's +what set n is right so if you add these + + align:start position:0% +what set n is right so if you add these + + + align:start position:0% +what set n is right so if you add these +two this is converging to one this is + + align:start position:0% +two this is converging to one this is + + + align:start position:0% +two this is converging to one this is +converging to zero by the algebraic + + align:start position:0% +converging to zero by the algebraic + + + align:start position:0% +converging to zero by the algebraic +property of limits this converts also to + + align:start position:0% +property of limits this converts also to + + + align:start position:0% +property of limits this converts also to +the sum of the limit so this here + + align:start position:0% +the sum of the limit so this here + + + align:start position:0% +the sum of the limit so this here +converts to one right now I can also + + align:start position:0% +converts to one right now I can also + + + align:start position:0% +converts to one right now I can also +define a sequence where I'm just adding + + align:start position:0% +define a sequence where I'm just adding + + + align:start position:0% +define a sequence where I'm just adding +set in and then I'm adding x in and then + + align:start position:0% +set in and then I'm adding x in and then + + + align:start position:0% +set in and then I'm adding x in and then +I'm adding y in right + + align:start position:0% + + + + align:start position:0% + +this here converts to one this here to + + align:start position:0% +this here converts to one this here to + + + align:start position:0% +this here converts to one this here to +zero + + align:start position:0% +zero + + + align:start position:0% +zero +this here to zero. So the sum here also + + align:start position:0% +this here to zero. So the sum here also + + + align:start position:0% +this here to zero. So the sum here also +converge to the sum of the limit but the + + align:start position:0% +converge to the sum of the limit but the + + + align:start position:0% +converge to the sum of the limit but the +sum of the limits is one. + + align:start position:0% +sum of the limits is one. + + + align:start position:0% +sum of the limits is one. +Now you have that + + align:start position:0% +Now you have that + + + align:start position:0% +Now you have that +one over c sorry now you have that + + align:start position:0% + + + + align:start position:0% + +put it up here and then then I will I'll + + align:start position:0% +put it up here and then then I will I'll + + + align:start position:0% +put it up here and then then I will I'll +just go over here. + + align:start position:0% + + + + align:start position:0% + +So now you have that um that CN + + align:start position:0% +So now you have that um that CN + + + align:start position:0% +So now you have that um that CN +converts to one. + + align:start position:0% +converts to one. + + + align:start position:0% +converts to one. +Um and let's call this here C. And so in + + align:start position:0% +Um and let's call this here C. And so in + + + align:start position:0% +Um and let's call this here C. And so in +in particular, I mean all of these + + align:start position:0% +in particular, I mean all of these + + + align:start position:0% +in particular, I mean all of these +numbers here, these things here are all + + align:start position:0% +numbers here, these things here are all + + + align:start position:0% +numbers here, these things here are all +strictly positive. So each of the CN are + + align:start position:0% +strictly positive. So each of the CN are + + + align:start position:0% +strictly positive. So each of the CN are +strictly positive. So they're definitely + + align:start position:0% +strictly positive. So they're definitely + + + align:start position:0% +strictly positive. So they're definitely +not zero, right? So the CN so not only + + align:start position:0% +not zero, right? So the CN so not only + + + align:start position:0% +not zero, right? So the CN so not only +do they converge to one but the CN are + + align:start position:0% +do they converge to one but the CN are + + + align:start position:0% +do they converge to one but the CN are +not equal to zero and the limit C well + + align:start position:0% +not equal to zero and the limit C well + + + align:start position:0% +not equal to zero and the limit C well +that's one so that's of course not equal + + align:start position:0% +that's one so that's of course not equal + + + align:start position:0% +that's one so that's of course not equal +to zero either right so you can apply + + align:start position:0% +to zero either right so you can apply + + + align:start position:0% +to zero either right so you can apply +the fourth rule here the fourth rule for + + align:start position:0% +the fourth rule here the fourth rule for + + + align:start position:0% +the fourth rule here the fourth rule for +the sequence not for the sequence CN not + + align:start position:0% +the sequence not for the sequence CN not + + + align:start position:0% +the sequence not for the sequence CN not +right so apply the fourth rule to the + + align:start position:0% +right so apply the fourth rule to the + + + align:start position:0% +right so apply the fourth rule to the +sequence CN and then you have that one + + align:start position:0% +sequence CN and then you have that one + + + align:start position:0% +sequence CN and then you have that one +over CN converge to one / c. But one c + + align:start position:0% +over CN converge to one / c. But one c + + + align:start position:0% +over CN converge to one / c. But one c +was one. So this is one. Right? + + align:start position:0% +was one. So this is one. Right? + + + align:start position:0% +was one. So this is one. Right? +Now you can look at at um at bn + + align:start position:0% +Now you can look at at um at bn + + + align:start position:0% +Now you can look at at um at bn +* 1 / cn. But bn * 1 / cn, right? + + align:start position:0% +* 1 / cn. But bn * 1 / cn, right? + + + align:start position:0% +* 1 / cn. But bn * 1 / cn, right? +Remember what bn was? Here's bn. And bn + + align:start position:0% +Remember what bn was? Here's bn. And bn + + + align:start position:0% +Remember what bn was? Here's bn. And bn +is really the denominator up here. + + align:start position:0% +is really the denominator up here. + + + align:start position:0% +is really the denominator up here. +Right? It's the nominator up here. when + + align:start position:0% +Right? It's the nominator up here. when + + + align:start position:0% +Right? It's the nominator up here. when +you have divided by n squ on both sides + + align:start position:0% +you have divided by n squ on both sides + + + align:start position:0% +you have divided by n squ on both sides +uh by not on both sides but both in the + + align:start position:0% +uh by not on both sides but both in the + + + align:start position:0% +uh by not on both sides but both in the +top and the denominator. + + align:start position:0% +top and the denominator. + + + align:start position:0% +top and the denominator. +So bn is the denominator and cn is the + + align:start position:0% +So bn is the denominator and cn is the + + + align:start position:0% +So bn is the denominator and cn is the +denominator. So bn divided by CN this + + align:start position:0% +denominator. So bn divided by CN this + + + align:start position:0% +denominator. So bn divided by CN this +here is a n right + + align:start position:0% +here is a n right + + + align:start position:0% +here is a n right +and now this here converge that's what + + align:start position:0% +and now this here converge that's what + + + align:start position:0% +and now this here converge that's what +we saw over there using the algebraic + + align:start position:0% +we saw over there using the algebraic + + + align:start position:0% +we saw over there using the algebraic +rule it converts to one this here also + + align:start position:0% +rule it converts to one this here also + + + align:start position:0% +rule it converts to one this here also +converts to one by the algebraic rules + + align:start position:0% +converts to one by the algebraic rules + + + align:start position:0% +converts to one by the algebraic rules +number three of the algebraic rules is + + align:start position:0% +number three of the algebraic rules is + + + align:start position:0% +number three of the algebraic rules is +that for the product it will also + + align:start position:0% +that for the product it will also + + + align:start position:0% +that for the product it will also +converge so and it converts to the + + align:start position:0% +converge so and it converts to the + + + align:start position:0% +converge so and it converts to the +product of the limits so that's one + + align:start position:0% +product of the limits so that's one + + + align:start position:0% +product of the limits so that's one +And obviously so I you know this is like + + align:start position:0% +And obviously so I you know this is like + + + align:start position:0% +And obviously so I you know this is like +when you're looking at a sequence it's + + align:start position:0% +when you're looking at a sequence it's + + + align:start position:0% +when you're looking at a sequence it's +often uh expressed in some form with + + align:start position:0% +often uh expressed in some form with + + + align:start position:0% +often uh expressed in some form with +some functions like this and you and you + + align:start position:0% +some functions like this and you and you + + + align:start position:0% +some functions like this and you and you +do this reduction and very quickly you + + align:start position:0% +do this reduction and very quickly you + + + align:start position:0% +do this reduction and very quickly you +know this would be almost automatic + + align:start position:0% +know this would be almost automatic + + + align:start position:0% +know this would be almost automatic +right I mean this is too easy almost + + align:start position:0% +right I mean this is too easy almost + + + align:start position:0% +right I mean this is too easy almost +this one I mean you know this is the + + align:start position:0% +this one I mean you know this is the + + + align:start position:0% +this one I mean you know this is the +first time you see it but you know in in + + align:start position:0% +first time you see it but you know in in + + + align:start position:0% +first time you see it but you know in in +a couple of weeks this will feel uh too + + align:start position:0% +a couple of weeks this will feel uh too + + + align:start position:0% +a couple of weeks this will feel uh too +easy uh then then there would be + + align:start position:0% +easy uh then then there would be + + + align:start position:0% +easy uh then then there would be +something more complicated. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +So that's that's the algebraic rules uh + + align:start position:0% +So that's that's the algebraic rules uh + + + align:start position:0% +So that's that's the algebraic rules uh +of for sequences. + + align:start position:0% +of for sequences. + + + align:start position:0% +of for sequences. +The next thing I want to talk about is I + + align:start position:0% +The next thing I want to talk about is I + + + align:start position:0% +The next thing I want to talk about is I +want to try to make more precise + + align:start position:0% +want to try to make more precise + + + align:start position:0% +want to try to make more precise +um you know this about square. I mean, + + align:start position:0% +um you know this about square. I mean, + + + align:start position:0% +um you know this about square. I mean, +you know, we made it pretty precise, but + + align:start position:0% +you know, we made it pretty precise, but + + + align:start position:0% +you know, we made it pretty precise, but +I want to think about + + align:start position:0% +I want to think about + + + align:start position:0% +I want to think about +uh uh I don't have a very good eraser, + + align:start position:0% +uh uh I don't have a very good eraser, + + + align:start position:0% +uh uh I don't have a very good eraser, +unfortunately. Let me just see. This is + + align:start position:0% +unfortunately. Let me just see. This is + + + align:start position:0% +unfortunately. Let me just see. This is +a better one. + + align:start position:0% +a better one. + + + align:start position:0% +a better one. +This one here will make it very dirty. + + align:start position:0% +This one here will make it very dirty. + + + align:start position:0% +This one here will make it very dirty. +Okay. So, so the next thing I want to + + align:start position:0% +Okay. So, so the next thing I want to + + + align:start position:0% +Okay. So, so the next thing I want to +So, we did define square of two and we + + align:start position:0% +So, we did define square of two and we + + + align:start position:0% +So, we did define square of two and we +talked about that quite extensively. how + + align:start position:0% +talked about that quite extensively. how + + + align:start position:0% +talked about that quite extensively. how +square root two, you know, how it really + + align:start position:0% +square root two, you know, how it really + + + align:start position:0% +square root two, you know, how it really +was defined and it was a real number and + + align:start position:0% +was defined and it was a real number and + + + align:start position:0% +was defined and it was a real number and +the real numbers followed from + + align:start position:0% +the real numbers followed from + + + align:start position:0% +the real numbers followed from +that the field the reals is complete. + + align:start position:0% +that the field the reals is complete. + + + align:start position:0% +that the field the reals is complete. +But we also + + align:start position:0% +But we also + + + align:start position:0% +But we also +we also sort of in the back of our mind + + align:start position:0% +we also sort of in the back of our mind + + + align:start position:0% +we also sort of in the back of our mind +we had that we already sort of knew what + + align:start position:0% +we had that we already sort of knew what + + + align:start position:0% +we had that we already sort of knew what +square root of two were, right? Because + + align:start position:0% +square root of two were, right? Because + + + align:start position:0% +square root of two were, right? Because +when you think about square root two, I + + align:start position:0% +when you think about square root two, I + + + align:start position:0% +when you think about square root two, I +mean at least I think about square root + + align:start position:0% +mean at least I think about square root + + + align:start position:0% +mean at least I think about square root +two. I think about it as 1.4. I mean + + align:start position:0% +two. I think about it as 1.4. I mean + + + align:start position:0% +two. I think about it as 1.4. I mean +just because you can't really express it + + align:start position:0% +just because you can't really express it + + + align:start position:0% +just because you can't really express it +as a fraction. So you think about it as + + align:start position:0% +as a fraction. So you think about it as + + + align:start position:0% +as a fraction. So you think about it as +1.414 + + align:start position:0% +1.414 + + + align:start position:0% +1.414 +etc. And then I don't remember I don't + + align:start position:0% +etc. And then I don't remember I don't + + + align:start position:0% +etc. And then I don't remember I don't +remember the second years third and + + align:start position:0% +remember the second years third and + + + align:start position:0% +remember the second years third and +fourth whatever but you know you may + + align:start position:0% +fourth whatever but you know you may + + + align:start position:0% +fourth whatever but you know you may +remember just a few of the digits fine + + align:start position:0% +remember just a few of the digits fine + + + align:start position:0% +remember just a few of the digits fine +and but so how do we make so so that's + + align:start position:0% +and but so how do we make so so that's + + + align:start position:0% +and but so how do we make so so that's +sort of our intuition + + align:start position:0% +sort of our intuition + + + align:start position:0% +sort of our intuition +uh with 1.4 four with with square two. + + align:start position:0% +uh with 1.4 four with with square two. + + + align:start position:0% +uh with 1.4 four with with square two. +Uh but how do we make this more precise? + + align:start position:0% +Uh but how do we make this more precise? + + + align:start position:0% +Uh but how do we make this more precise? +Right? And so to make this more precise, + + align:start position:0% +Right? And so to make this more precise, + + + align:start position:0% +Right? And so to make this more precise, +we want to look at particular sequences. + + align:start position:0% +we want to look at particular sequences. + + + align:start position:0% +we want to look at particular sequences. +So what's called monotone + + align:start position:0% +So what's called monotone + + + align:start position:0% +So what's called monotone +sequences? + + align:start position:0% + + + + align:start position:0% + +So what is a mono sequence? + + align:start position:0% +So what is a mono sequence? + + + align:start position:0% +So what is a mono sequence? +So there's two types of monotom + + align:start position:0% +So there's two types of monotom + + + align:start position:0% +So there's two types of monotom +sequence. There's one which is monot + + align:start position:0% +sequence. There's one which is monot + + + align:start position:0% +sequence. There's one which is monot +increasing sequence + + align:start position:0% + + + + align:start position:0% + +and then there's similarly monotum + + align:start position:0% +and then there's similarly monotum + + + align:start position:0% +and then there's similarly monotum +decreasing sequence. So a monotum + + align:start position:0% +decreasing sequence. So a monotum + + + align:start position:0% +decreasing sequence. So a monotum +increasing sequence this is just means + + align:start position:0% +increasing sequence this is just means + + + align:start position:0% +increasing sequence this is just means +that for all n + + align:start position:0% + + + + align:start position:0% + +you have that the next element is larger + + align:start position:0% +you have that the next element is larger + + + align:start position:0% +you have that the next element is larger +or equal to the previous element. That's + + align:start position:0% +or equal to the previous element. That's + + + align:start position:0% +or equal to the previous element. That's +a mono increasing sequence. Right? Some + + align:start position:0% +a mono increasing sequence. Right? Some + + + align:start position:0% +a mono increasing sequence. Right? Some +people talk about strictly monotum + + align:start position:0% +people talk about strictly monotum + + + align:start position:0% +people talk about strictly monotum +increasing and then this have to be a + + align:start position:0% +increasing and then this have to be a + + + align:start position:0% +increasing and then this have to be a +strict. + + align:start position:0% + + + + align:start position:0% + +Uh the second thing is kind of the + + align:start position:0% +Uh the second thing is kind of the + + + align:start position:0% +Uh the second thing is kind of the +obvious parallel to this is monoton + + align:start position:0% +obvious parallel to this is monoton + + + align:start position:0% +obvious parallel to this is monoton +decreasing + + align:start position:0% + + + + align:start position:0% + +decreasing sequences. + + align:start position:0% + + + + align:start position:0% + +So that's these two types. Okay. And + + align:start position:0% +So that's these two types. Okay. And + + + align:start position:0% +So that's these two types. Okay. And +this just means that the next element so + + align:start position:0% +this just means that the next element so + + + align:start position:0% +this just means that the next element so +a n + one is less or equal to the + + align:start position:0% +a n + one is less or equal to the + + + align:start position:0% +a n + one is less or equal to the +previous one. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +And so now there's a theorem and and + + align:start position:0% +And so now there's a theorem and and + + + align:start position:0% +And so now there's a theorem and and +I'll prove this in a in just a minute. + + align:start position:0% +I'll prove this in a in just a minute. + + + align:start position:0% +I'll prove this in a in just a minute. +But I also want to + + align:start position:0% +But I also want to + + + align:start position:0% +But I also want to +and I want to come back to square root + + align:start position:0% +and I want to come back to square root + + + align:start position:0% +and I want to come back to square root +of two and then I want to look at + + align:start position:0% +of two and then I want to look at + + + align:start position:0% +of two and then I want to look at +another + + align:start position:0% +another + + + align:start position:0% +another +classical example of a monotum sequence. + + align:start position:0% + + + + align:start position:0% + +So + + align:start position:0% +So + + + align:start position:0% +So +um + + align:start position:0% +um + + + align:start position:0% +um +right so this is a mono sequence and now + + align:start position:0% +right so this is a mono sequence and now + + + align:start position:0% +right so this is a mono sequence and now +let me state the mono convergence + + align:start position:0% +let me state the mono convergence + + + align:start position:0% +let me state the mono convergence +theorem. + + align:start position:0% + + + + align:start position:0% + +So suppose that so this is the following + + align:start position:0% +So suppose that so this is the following + + + align:start position:0% +So suppose that so this is the following +theorem. Suppose that + + align:start position:0% + + + + align:start position:0% + +that and there's two versions of this. + + align:start position:0% +that and there's two versions of this. + + + align:start position:0% +that and there's two versions of this. +There's one version for monotum + + align:start position:0% +There's one version for monotum + + + align:start position:0% +There's one version for monotum +increasing sequence and then there's one + + align:start position:0% +increasing sequence and then there's one + + + align:start position:0% +increasing sequence and then there's one +version for mono decreasing sequence. I + + align:start position:0% +version for mono decreasing sequence. I + + + align:start position:0% +version for mono decreasing sequence. I +just state one of them because the other + + align:start position:0% +just state one of them because the other + + + align:start position:0% +just state one of them because the other +one's kind of obvious parallel. So + + align:start position:0% +one's kind of obvious parallel. So + + + align:start position:0% +one's kind of obvious parallel. So +suppose that a end is a monotone + + align:start position:0% + + + + align:start position:0% + +increasing sequence + + align:start position:0% +increasing sequence + + + align:start position:0% +increasing sequence +[Applause] + + align:start position:0% + + + + align:start position:0% + +then it is bounded + + align:start position:0% + + + + align:start position:0% + +bounded. So this just means that there + + align:start position:0% +bounded. So this just means that there + + + align:start position:0% +bounded. So this just means that there +exists + + align:start position:0% +exists + + + align:start position:0% +exists +i.e. + + align:start position:0% +i.e. + + + align:start position:0% +i.e. +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +there exist + + align:start position:0% + + + + align:start position:0% + +some a real number. + + align:start position:0% +some a real number. + + + align:start position:0% +some a real number. +So that's + + align:start position:0% +So that's + + + align:start position:0% +So that's +right. You have a1 this here is that is + + align:start position:0% +right. You have a1 this here is that is + + + align:start position:0% +right. You have a1 this here is that is +monotum right this is monotum that they + + align:start position:0% +monotum right this is monotum that they + + + align:start position:0% +monotum right this is monotum that they +cannot increase but but the claim is + + align:start position:0% +cannot increase but but the claim is + + + align:start position:0% +cannot increase but but the claim is +that now the all of the a is lesser + + align:start position:0% +that now the all of the a is lesser + + + align:start position:0% +that now the all of the a is lesser +equal to this a + + align:start position:0% +equal to this a + + + align:start position:0% +equal to this a +it's any monotum increasing sequence is + + align:start position:0% +it's any monotum increasing sequence is + + + align:start position:0% +it's any monotum increasing sequence is +clearly bounded from below right because + + align:start position:0% +clearly bounded from below right because + + + align:start position:0% +clearly bounded from below right because +already the first element is a lower + + align:start position:0% +already the first element is a lower + + + align:start position:0% +already the first element is a lower +bound right so if you have a mono + + align:start position:0% +bound right so if you have a mono + + + align:start position:0% +bound right so if you have a mono +increasing sequence then Um + + align:start position:0% +increasing sequence then Um + + + align:start position:0% +increasing sequence then Um +then uh that is bounded then it's + + align:start position:0% +then uh that is bounded then it's + + + align:start position:0% +then uh that is bounded then it's +convergence + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +uh we limit say we limit + + align:start position:0% + + + + align:start position:0% + +a + + align:start position:0% +a + + + align:start position:0% +a +where + + align:start position:0% +where + + + align:start position:0% +where +a is the soup + + align:start position:0% +a is the soup + + + align:start position:0% +a is the soup +of the a inch. + + align:start position:0% + + + + align:start position:0% + +So that is a mono convergence sequence. + + align:start position:0% +So that is a mono convergence sequence. + + + align:start position:0% +So that is a mono convergence sequence. +Okay. and and and that is the the kind + + align:start position:0% +Okay. and and and that is the the kind + + + align:start position:0% +Okay. and and and that is the the kind +of main theorem about mono convergent + + align:start position:0% +of main theorem about mono convergent + + + align:start position:0% +of main theorem about mono convergent +sequence is that if you have a monotum + + align:start position:0% +sequence is that if you have a monotum + + + align:start position:0% +sequence is that if you have a monotum +increasing sequence + + align:start position:0% +increasing sequence + + + align:start position:0% +increasing sequence +that is bounded then it's also + + align:start position:0% +that is bounded then it's also + + + align:start position:0% +that is bounded then it's also +convergence right and likewise if you + + align:start position:0% +convergence right and likewise if you + + + align:start position:0% +convergence right and likewise if you +have a monotum decreasing sequence that + + align:start position:0% +have a monotum decreasing sequence that + + + align:start position:0% +have a monotum decreasing sequence that +is bounded from below + + align:start position:0% +is bounded from below + + + align:start position:0% +is bounded from below +right then it is also convergent and so + + align:start position:0% +right then it is also convergent and so + + + align:start position:0% +right then it is also convergent and so +maybe maybe I will state it + + align:start position:0% +maybe maybe I will state it + + + align:start position:0% +maybe maybe I will state it +u but it's is the obvious parallel. + + align:start position:0% + + + + align:start position:0% + +So, + + align:start position:0% +So, + + + align:start position:0% +So, +so this is part one + + align:start position:0% +so this is part one + + + align:start position:0% +so this is part one +of the monome converting sequence. + + align:start position:0% +of the monome converting sequence. + + + align:start position:0% +of the monome converting sequence. +Part two of part B is that if + + align:start position:0% +Part two of part B is that if + + + align:start position:0% +Part two of part B is that if +if A is a monotone + + align:start position:0% + + + + align:start position:0% + +decreasing sequence + + align:start position:0% + + + + align:start position:0% + +sequence + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% +then + + + align:start position:0% +then +uh that is bounded uh that is + + align:start position:0% +uh that is bounded uh that is + + + align:start position:0% +uh that is bounded uh that is +that is bounded from below. + + align:start position:0% + + + + align:start position:0% + +Then + + align:start position:0% + + + + align:start position:0% + +uh a is convergent + + align:start position:0% +uh a is convergent + + + align:start position:0% +uh a is convergent +with limit a where a is now the in + + align:start position:0% +with limit a where a is now the in + + + align:start position:0% +with limit a where a is now the in +of these numbers. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% + + + + align:start position:0% + +Now, + + align:start position:0% +Now, + + + align:start position:0% +Now, +so you might say the first thing you + + align:start position:0% +so you might say the first thing you + + + align:start position:0% +so you might say the first thing you +might say, we'll come to square root two + + align:start position:0% +might say, we'll come to square root two + + + align:start position:0% +might say, we'll come to square root two +in just a minute, but you may see that + + align:start position:0% +in just a minute, but you may see that + + + align:start position:0% +in just a minute, but you may see that +this seems rather special, you know, + + align:start position:0% +this seems rather special, you know, + + + align:start position:0% +this seems rather special, you know, +like if you take a random uh sequence, + + align:start position:0% +like if you take a random uh sequence, + + + align:start position:0% +like if you take a random uh sequence, +obviously it's not going to be monitor. + + align:start position:0% + + + + align:start position:0% + +Um but but here's the thing that so + + align:start position:0% +Um but but here's the thing that so + + + align:start position:0% +Um but but here's the thing that so +uh let + + align:start position:0% + + + + align:start position:0% + +be any bounded sequence. + + align:start position:0% + + + + align:start position:0% + +So bounded again means that it's bounded + + align:start position:0% +So bounded again means that it's bounded + + + align:start position:0% +So bounded again means that it's bounded +from above and bounded from below. So if + + align:start position:0% +from above and bounded from below. So if + + + align:start position:0% +from above and bounded from below. So if +you take any boundless sequence + + align:start position:0% +you take any boundless sequence + + + align:start position:0% +you take any boundless sequence +then we can form two other sequences. + + align:start position:0% + + + + align:start position:0% + +Two other sequences + + align:start position:0% +Two other sequences + + + align:start position:0% +Two other sequences +I mean obviously form many other but + + align:start position:0% +I mean obviously form many other but + + + align:start position:0% +I mean obviously form many other but +here's two other very natural + + align:start position:0% +here's two other very natural + + + align:start position:0% +here's two other very natural +uh sequences. + + align:start position:0% + + + + align:start position:0% + +The first one I call BN + + align:start position:0% +The first one I call BN + + + align:start position:0% +The first one I call BN +and BN is is the soup + + align:start position:0% + + + + align:start position:0% + +of where you're taking where you're + + align:start position:0% +of where you're taking where you're + + + align:start position:0% +of where you're taking where you're +starting at a end + + align:start position:0% +starting at a end + + + align:start position:0% +starting at a end +and then you take the soup of all of the + + align:start position:0% +and then you take the soup of all of the + + + align:start position:0% +and then you take the soup of all of the +ones from A in and outwards in the + + align:start position:0% +ones from A in and outwards in the + + + align:start position:0% +ones from A in and outwards in the +sequence. Right? So this is one + + align:start position:0% +sequence. Right? So this is one + + + align:start position:0% +sequence. Right? So this is one +sequence + + align:start position:0% +sequence + + + align:start position:0% +sequence +right we know that that you know the set + + align:start position:0% +right we know that that you know the set + + + align:start position:0% +right we know that that you know the set +of a ends is bounded right so you can + + align:start position:0% +of a ends is bounded right so you can + + + align:start position:0% +of a ends is bounded right so you can +certainly take the soup and you get a + + align:start position:0% +certainly take the soup and you get a + + + align:start position:0% +certainly take the soup and you get a +real number right that's that that gives + + align:start position:0% +real number right that's that that gives + + + align:start position:0% +real number right that's that that gives +you another sequence + + align:start position:0% +you another sequence + + + align:start position:0% +you another sequence +you can also look at cn similarly where + + align:start position:0% +you can also look at cn similarly where + + + align:start position:0% +you can also look at cn similarly where +you take instead of the soup you take + + align:start position:0% +you take instead of the soup you take + + + align:start position:0% +you take instead of the soup you take +the in of the same that + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +like that. All right. So, in particular, + + align:start position:0% +like that. All right. So, in particular, + + + align:start position:0% +like that. All right. So, in particular, +right, just to make sure it's totally + + align:start position:0% +right, just to make sure it's totally + + + align:start position:0% +right, just to make sure it's totally +clear + + align:start position:0% + + + + align:start position:0% + +that + + align:start position:0% +that + + + align:start position:0% +that +that if you were looking at + + align:start position:0% +that if you were looking at + + + align:start position:0% +that if you were looking at +say BN, so what is BN? If you're looking + + align:start position:0% +say BN, so what is BN? If you're looking + + + align:start position:0% +say BN, so what is BN? If you're looking +at say B3 + + align:start position:0% +at say B3 + + + align:start position:0% +at say B3 +then this is the soup where you're + + align:start position:0% +then this is the soup where you're + + + align:start position:0% +then this is the soup where you're +starting at A3 A4 + + align:start position:0% +starting at A3 A4 + + + align:start position:0% +starting at A3 A4 +etc. + + align:start position:0% +etc. + + + align:start position:0% +etc. +And so you see of course that B23 here + + align:start position:0% +And so you see of course that B23 here + + + align:start position:0% +And so you see of course that B23 here +well obviously B3 is bigger equal + + align:start position:0% +well obviously B3 is bigger equal + + + align:start position:0% +well obviously B3 is bigger equal +to B2 right because B2 here + + align:start position:0% +to B2 right because B2 here + + + align:start position:0% +to B2 right because B2 here +is sorry it's no it's not bigger equal + + align:start position:0% +is sorry it's no it's not bigger equal + + + align:start position:0% +is sorry it's no it's not bigger equal +to it's lesser equal to B2 + + align:start position:0% +to it's lesser equal to B2 + + + align:start position:0% +to it's lesser equal to B2 +because you see in B2 the definition of + + align:start position:0% +because you see in B2 the definition of + + + align:start position:0% +because you see in B2 the definition of +B2 so let's just write B2 down + + align:start position:0% +B2 so let's just write B2 down + + + align:start position:0% +B2 so let's just write B2 down +so B2 is that you take the soup here of + + align:start position:0% +so B2 is that you take the soup here of + + + align:start position:0% +so B2 is that you take the soup here of +A2 and then A3 + + align:start position:0% +A2 and then A3 + + + align:start position:0% +A2 and then A3 +A4 etc. + + align:start position:0% +A4 etc. + + + align:start position:0% +A4 etc. +Right? But you see that B2 here it's + + align:start position:0% +Right? But you see that B2 here it's + + + align:start position:0% +Right? But you see that B2 here it's +both of them are defined to be soup but + + align:start position:0% +both of them are defined to be soup but + + + align:start position:0% +both of them are defined to be soup but +B2 is defined as soup over a larger set + + align:start position:0% +B2 is defined as soup over a larger set + + + align:start position:0% +B2 is defined as soup over a larger set +because in addition to these elements it + + align:start position:0% +because in addition to these elements it + + + align:start position:0% +because in addition to these elements it +also includes A2 right. So clearly B2 + + align:start position:0% +also includes A2 right. So clearly B2 + + + align:start position:0% +also includes A2 right. So clearly B2 +here is bigger equal to B3 + + align:start position:0% +here is bigger equal to B3 + + + align:start position:0% +here is bigger equal to B3 +right and in fact the same argument + + align:start position:0% +right and in fact the same argument + + + align:start position:0% +right and in fact the same argument +tells you that if you take B + + align:start position:0% +tells you that if you take B + + + align:start position:0% +tells you that if you take B +n + one then this is or bn sorry bn is + + align:start position:0% +n + one then this is or bn sorry bn is + + + align:start position:0% +n + one then this is or bn sorry bn is +bigger equal to bn + one + + align:start position:0% +bigger equal to bn + one + + + align:start position:0% +bigger equal to bn + one +because this here is the soup over a + + align:start position:0% +because this here is the soup over a + + + align:start position:0% +because this here is the soup over a +larger set it's soup over all the ones + + align:start position:0% +larger set it's soup over all the ones + + + align:start position:0% +larger set it's soup over all the ones +you take soup in here plus a n right so + + align:start position:0% +you take soup in here plus a n right so + + + align:start position:0% +you take soup in here plus a n right so +you have this property here right and so + + align:start position:0% +you have this property here right and so + + + align:start position:0% +you have this property here right and so +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +>> what do you + + align:start position:0% + + + + align:start position:0% + +Yeah. + + align:start position:0% + + + + align:start position:0% + +If it's a monot increasing um + + align:start position:0% +If it's a monot increasing um + + + align:start position:0% +If it's a monot increasing um +>> yeah because monotum increasing uh then + + align:start position:0% +>> yeah because monotum increasing uh then + + + align:start position:0% +>> yeah because monotum increasing uh then +this here uh right yeah then it becomes + + align:start position:0% +this here uh right yeah then it becomes + + + align:start position:0% +this here uh right yeah then it becomes +very special. + + align:start position:0% +very special. + + + align:start position:0% +very special. +Uh so it's it's if you take a mon if the + + align:start position:0% +Uh so it's it's if you take a mon if the + + + align:start position:0% +Uh so it's it's if you take a mon if the +a was monoton increasing then the all of + + align:start position:0% +a was monoton increasing then the all of + + + align:start position:0% +a was monoton increasing then the all of +these any element here would just be the + + align:start position:0% +these any element here would just be the + + + align:start position:0% +these any element here would just be the +a we talked about before it would always + + align:start position:0% +a we talked about before it would always + + + align:start position:0% +a we talked about before it would always +be the limit. + + align:start position:0% +be the limit. + + + align:start position:0% +be the limit. +So so it's um it's it somehow wouldn't + + align:start position:0% +So so it's um it's it somehow wouldn't + + + align:start position:0% +So so it's um it's it somehow wouldn't +be that interesting a sequence. It would + + align:start position:0% +be that interesting a sequence. It would + + + align:start position:0% +be that interesting a sequence. It would +be a constant sequence and and it would + + align:start position:0% +be a constant sequence and and it would + + + align:start position:0% +be a constant sequence and and it would +be just + + align:start position:0% +be just + + + align:start position:0% +be just +>> but but but that but nevertheless it's a + + align:start position:0% +>> but but but that but nevertheless it's a + + + align:start position:0% +>> but but but that but nevertheless it's a +good example you know. I guess that's + + align:start position:0% +good example you know. I guess that's + + + align:start position:0% +good example you know. I guess that's +still anybody. + + align:start position:0% +still anybody. + + + align:start position:0% +still anybody. +>> Yeah. Yeah. Definitely. Right. Because + + align:start position:0% +>> Yeah. Yeah. Definitely. Right. Because + + + align:start position:0% +>> Yeah. Yeah. Definitely. Right. Because +it's just constant. Exactly. + + align:start position:0% +it's just constant. Exactly. + + + align:start position:0% +it's just constant. Exactly. +>> It's a it's a good example, but it's + + align:start position:0% +>> It's a it's a good example, but it's + + + align:start position:0% +>> It's a it's a good example, but it's +just kind of almost like too simple + + align:start position:0% +just kind of almost like too simple + + + align:start position:0% +just kind of almost like too simple +because you get a constant sequence, + + align:start position:0% +because you get a constant sequence, + + + align:start position:0% +because you get a constant sequence, +right? + + align:start position:0% +right? + + + align:start position:0% +right? +So, okay. So, we have for this sequence + + align:start position:0% +So, okay. So, we have for this sequence + + + align:start position:0% +So, okay. So, we have for this sequence +that we defined. So we have again these + + align:start position:0% +that we defined. So we have again these + + + align:start position:0% +that we defined. So we have again these +if you take any sequence then you get + + align:start position:0% +if you take any sequence then you get + + + align:start position:0% +if you take any sequence then you get +then you have two sequences B and a CN + + align:start position:0% +then you have two sequences B and a CN + + + align:start position:0% +then you have two sequences B and a CN +and B and here is now a decreasing + + align:start position:0% +and B and here is now a decreasing + + + align:start position:0% +and B and here is now a decreasing +sequence and in instead of writing + + align:start position:0% +sequence and in instead of writing + + + align:start position:0% +sequence and in instead of writing +decreasing sequence then uh it's much + + align:start position:0% +decreasing sequence then uh it's much + + + align:start position:0% +decreasing sequence then uh it's much +easier to write it like this. This is + + align:start position:0% +easier to write it like this. This is + + + align:start position:0% +easier to write it like this. This is +pretty standard. I mean you know it's + + align:start position:0% +pretty standard. I mean you know it's + + + align:start position:0% +pretty standard. I mean you know it's +just to uh if you just look quickly at + + align:start position:0% +just to uh if you just look quickly at + + + align:start position:0% +just to uh if you just look quickly at +it uh you know what this means. + + align:start position:0% +it uh you know what this means. + + + align:start position:0% +it uh you know what this means. +going to write out but let's look at CN + + align:start position:0% +going to write out but let's look at CN + + + align:start position:0% +going to write out but let's look at CN +also + + align:start position:0% +also + + + align:start position:0% +also +remember that we assume that a n we a + + align:start position:0% +remember that we assume that a n we a + + + align:start position:0% +remember that we assume that a n we a +could be any sequence but it is supposed + + align:start position:0% +could be any sequence but it is supposed + + + align:start position:0% +could be any sequence but it is supposed +to be bounded right so this is now a + + align:start position:0% +to be bounded right so this is now a + + + align:start position:0% +to be bounded right so this is now a +monotum decreasing sequence that is + + align:start position:0% +monotum decreasing sequence that is + + + align:start position:0% +monotum decreasing sequence that is +bounded so it actually has a limit right + + align:start position:0% +bounded so it actually has a limit right + + + align:start position:0% +bounded so it actually has a limit right +the cs what about the cs so the cns + + align:start position:0% +the cs what about the cs so the cns + + + align:start position:0% +the cs what about the cs so the cns +So + + align:start position:0% +So + + + align:start position:0% +So +the CN + + align:start position:0% +the CN + + + align:start position:0% +the CN +well CN was defined to be the in + + align:start position:0% +well CN was defined to be the in + + + align:start position:0% +well CN was defined to be the in +starting at a end + + align:start position:0% +starting at a end + + + align:start position:0% +starting at a end +like that + + align:start position:0% + + + + align:start position:0% + +right + + align:start position:0% +right + + + align:start position:0% +right +so it' be starting like that and so this + + align:start position:0% +so it' be starting like that and so this + + + align:start position:0% +so it' be starting like that and so this +means that if you take CN + one + + align:start position:0% +means that if you take CN + one + + + align:start position:0% +means that if you take CN + one +then you take the infom But you don't + + align:start position:0% +then you take the infom But you don't + + + align:start position:0% +then you take the infom But you don't +include this element. Right? So it's a + + align:start position:0% +include this element. Right? So it's a + + + align:start position:0% +include this element. Right? So it's a +infreum over fewer elements. But then + + align:start position:0% +infreum over fewer elements. But then + + + align:start position:0% +infreum over fewer elements. But then +this here must be larger equal + + align:start position:0% +this here must be larger equal + + + align:start position:0% +this here must be larger equal +right to that. So you see that the + + align:start position:0% +right to that. So you see that the + + + align:start position:0% +right to that. So you see that the +sequence CN + + align:start position:0% +sequence CN + + + align:start position:0% +sequence CN +is monotum. This here is monotum + + align:start position:0% +is monotum. This here is monotum + + + align:start position:0% +is monotum. This here is monotum +increasing again is bounded and and and + + align:start position:0% +increasing again is bounded and and and + + + align:start position:0% +increasing again is bounded and and and +just copying from over there. The BN was + + align:start position:0% +just copying from over there. The BN was + + + align:start position:0% +just copying from over there. The BN was +decreasing. + + align:start position:0% +decreasing. + + + align:start position:0% +decreasing. +>> Okay. This is like I mean it's also like + + align:start position:0% +>> Okay. This is like I mean it's also like + + + align:start position:0% +>> Okay. This is like I mean it's also like +I mean this is an important thing. It's + + align:start position:0% +I mean this is an important thing. It's + + + align:start position:0% +I mean this is an important thing. It's +also something that you would see in lot + + align:start position:0% +also something that you would see in lot + + + align:start position:0% +also something that you would see in lot +of different context where you define + + align:start position:0% +of different context where you define + + + align:start position:0% +of different context where you define +something some sort of sub and then you + + align:start position:0% +something some sort of sub and then you + + + align:start position:0% +something some sort of sub and then you +have these property + + align:start position:0% +have these property + + + align:start position:0% +have these property +and so now the thing is that if you're + + align:start position:0% +and so now the thing is that if you're + + + align:start position:0% +and so now the thing is that if you're +looking at so aure it might not be so + + align:start position:0% +looking at so aure it might not be so + + + align:start position:0% +looking at so aure it might not be so +clear to compare a random element in + + align:start position:0% +clear to compare a random element in + + + align:start position:0% +clear to compare a random element in +this sequence to a random element in + + align:start position:0% +this sequence to a random element in + + + align:start position:0% +this sequence to a random element in +that but what is clear is that if you + + align:start position:0% +that but what is clear is that if you + + + align:start position:0% +that but what is clear is that if you +try to compare BN with CN And + + align:start position:0% +try to compare BN with CN And + + + align:start position:0% +try to compare BN with CN And +right + + align:start position:0% +right + + + align:start position:0% +right +it's the same set. It's the same set. + + align:start position:0% +it's the same set. It's the same set. + + + align:start position:0% +it's the same set. It's the same set. +And one you take the soup, the other you + + align:start position:0% +And one you take the soup, the other you + + + align:start position:0% +And one you take the soup, the other you +take the in. So of course BN is bigger + + align:start position:0% +take the in. So of course BN is bigger + + + align:start position:0% +take the in. So of course BN is bigger +equal to CN, + + align:start position:0% +equal to CN, + + + align:start position:0% +equal to CN, +right? So you have this, right? And so + + align:start position:0% +right? So you have this, right? And so + + + align:start position:0% +right? So you have this, right? And so +now you see that if you take like a + + align:start position:0% +now you see that if you take like a + + + align:start position:0% +now you see that if you take like a +random element here, if it was like + + align:start position:0% +random element here, if it was like + + + align:start position:0% +random element here, if it was like +further out, if it was N, sorry, if it + + align:start position:0% +further out, if it was N, sorry, if it + + + align:start position:0% +further out, if it was N, sorry, if it +was C N further out, I just write it as + + align:start position:0% +was C N further out, I just write it as + + + align:start position:0% +was C N further out, I just write it as +something further out. So you adding + + align:start position:0% +something further out. So you adding + + + align:start position:0% +something further out. So you adding +something else to it. So this would be + + align:start position:0% +something else to it. So this would be + + + align:start position:0% +something else to it. So this would be +like further out. We know that this + + align:start position:0% +like further out. We know that this + + + align:start position:0% +like further out. We know that this +sequence here. + + align:start position:0% +sequence here. + + + align:start position:0% +sequence here. +Yeah. Anyway, so you get Sorry, now + + align:start position:0% +Yeah. Anyway, so you get Sorry, now + + + align:start position:0% +Yeah. Anyway, so you get Sorry, now +you're getting this. I'm getting this + + align:start position:0% +you're getting this. I'm getting this + + + align:start position:0% +you're getting this. I'm getting this +here. + + align:start position:0% +here. + + + align:start position:0% +here. +like that + + align:start position:0% + + + + align:start position:0% + +and right so you have this so what you + + align:start position:0% +and right so you have this so what you + + + align:start position:0% +and right so you have this so what you +should what I should have done is that + + align:start position:0% +should what I should have done is that + + + align:start position:0% +should what I should have done is that +this sequence here so you have so let + + align:start position:0% +this sequence here so you have so let + + + align:start position:0% +this sequence here so you have so let +let me rather draw it like this so I + + align:start position:0% +let me rather draw it like this so I + + + align:start position:0% +let me rather draw it like this so I +have that this that so here is maybe C1 + + align:start position:0% +have that this that so here is maybe C1 + + + align:start position:0% +have that this that so here is maybe C1 +here is B1 + + align:start position:0% +here is B1 + + + align:start position:0% +here is B1 +and now the next one the next element + + align:start position:0% +and now the next one the next element + + + align:start position:0% +and now the next one the next element +the sequence C n is increasing and the + + align:start position:0% +the sequence C n is increasing and the + + + align:start position:0% +the sequence C n is increasing and the +sequence + + align:start position:0% +sequence + + + align:start position:0% +sequence +bn is decreasing. So then but you always + + align:start position:0% +bn is decreasing. So then but you always + + + align:start position:0% +bn is decreasing. So then but you always +have this here. So c2 have to lie to the + + align:start position:0% +have this here. So c2 have to lie to the + + + align:start position:0% +have this here. So c2 have to lie to the +right of this but it has to lie to the + + align:start position:0% +right of this but it has to lie to the + + + align:start position:0% +right of this but it has to lie to the +left of b2. + + align:start position:0% +left of b2. + + + align:start position:0% +left of b2. +So you're getting this here. + + align:start position:0% +So you're getting this here. + + + align:start position:0% +So you're getting this here. +So, so you see that this is a way to + + align:start position:0% +So, so you see that this is a way to + + + align:start position:0% +So, so you see that this is a way to +kind of you know this gives you a way to + + align:start position:0% +kind of you know this gives you a way to + + + align:start position:0% +kind of you know this gives you a way to +compare right that that the CN will + + align:start position:0% +compare right that that the CN will + + + align:start position:0% +compare right that that the CN will +always lie to the left of the BN. + + align:start position:0% +always lie to the left of the BN. + + + align:start position:0% +always lie to the left of the BN. +So you have so so now what we have done + + align:start position:0% +So you have so so now what we have done + + + align:start position:0% +So you have so so now what we have done +here is we took any boundary sequence + + align:start position:0% + + + + align:start position:0% + +and we formed two mono sequences. + + align:start position:0% +and we formed two mono sequences. + + + align:start position:0% +and we formed two mono sequences. +They're both mono + + align:start position:0% + + + + align:start position:0% + +And we have so so this means that now + + align:start position:0% +And we have so so this means that now + + + align:start position:0% +And we have so so this means that now +from the monot convergence that we + + align:start position:0% +from the monot convergence that we + + + align:start position:0% +from the monot convergence that we +haven't quite proven yet but from the + + align:start position:0% +haven't quite proven yet but from the + + + align:start position:0% +haven't quite proven yet but from the +mono convergence uh convergence theorem + + align:start position:0% +mono convergence uh convergence theorem + + + align:start position:0% +mono convergence uh convergence theorem +because these are bounded we have that + + align:start position:0% +because these are bounded we have that + + + align:start position:0% +because these are bounded we have that +bm converge converging they are going uh + + align:start position:0% +bm converge converging they are going uh + + + align:start position:0% +bm converge converging they are going uh +they're going down right so they're + + align:start position:0% +they're going down right so they're + + + align:start position:0% +they're going down right so they're +converging so one often would write it + + align:start position:0% +converging so one often would write it + + + align:start position:0% +converging so one often would write it +like this more suggestively + + align:start position:0% +like this more suggestively + + + align:start position:0% +like this more suggestively +that is converging downward to a limit B + + align:start position:0% +that is converging downward to a limit B + + + align:start position:0% +that is converging downward to a limit B +and the CN + + align:start position:0% +and the CN + + + align:start position:0% +and the CN +is converging upward to a limit C. + + align:start position:0% +is converging upward to a limit C. + + + align:start position:0% +is converging upward to a limit C. +Right? And so what you get is because of + + align:start position:0% +Right? And so what you get is because of + + + align:start position:0% +Right? And so what you get is because of +all of these elements, all the C ends + + align:start position:0% +all of these elements, all the C ends + + + align:start position:0% +all of these elements, all the C ends +lie to the left of the B ends. This + + align:start position:0% +lie to the left of the B ends. This + + + align:start position:0% +lie to the left of the B ends. This +means that and we we'll prove this later + + align:start position:0% +means that and we we'll prove this later + + + align:start position:0% +means that and we we'll prove this later +but it seems probably pretty obvious + + align:start position:0% +but it seems probably pretty obvious + + + align:start position:0% +but it seems probably pretty obvious +that the limit here C is less or equal + + align:start position:0% +that the limit here C is less or equal + + + align:start position:0% +that the limit here C is less or equal +to B + + align:start position:0% +to B + + + align:start position:0% +to B +and this so we'll come back to this also + + align:start position:0% +and this so we'll come back to this also + + + align:start position:0% +and this so we'll come back to this also +next time um when we talked I if I have + + align:start position:0% +next time um when we talked I if I have + + + align:start position:0% +next time um when we talked I if I have +time I'll talk a little bit about cushy + + align:start position:0% +time I'll talk a little bit about cushy + + + align:start position:0% +time I'll talk a little bit about cushy +sequence but I won't really prove too + + align:start position:0% +sequence but I won't really prove too + + + align:start position:0% +sequence but I won't really prove too +much about it and and and but this here + + align:start position:0% +much about it and and and but this here + + + align:start position:0% +much about it and and and but this here +will play a important role + + align:start position:0% +will play a important role + + + align:start position:0% +will play a important role +uh when we prove the the basic theorem + + align:start position:0% +uh when we prove the the basic theorem + + + align:start position:0% +uh when we prove the the basic theorem +about cushy sequences. + + align:start position:0% +about cushy sequences. + + + align:start position:0% +about cushy sequences. +Okay. So so the takeaway here at the + + align:start position:0% +Okay. So so the takeaway here at the + + + align:start position:0% +Okay. So so the takeaway here at the +moment is just that uh so you have you + + align:start position:0% +moment is just that uh so you have you + + + align:start position:0% +moment is just that uh so you have you +have this concept of a monot + + align:start position:0% +have this concept of a monot + + + align:start position:0% +have this concept of a monot +uh either increasing or decreasing + + align:start position:0% +uh either increasing or decreasing + + + align:start position:0% +uh either increasing or decreasing +sequence. If such a sequence is bounded + + align:start position:0% +sequence. If such a sequence is bounded + + + align:start position:0% +sequence. If such a sequence is bounded +then it's convergent. That's a mono + + align:start position:0% +then it's convergent. That's a mono + + + align:start position:0% +then it's convergent. That's a mono +convergence theorem. And again from any + + align:start position:0% +convergence theorem. And again from any + + + align:start position:0% +convergence theorem. And again from any +sequence + + align:start position:0% +sequence + + + align:start position:0% +sequence +any boundary sequence you can act that's + + align:start position:0% +any boundary sequence you can act that's + + + align:start position:0% +any boundary sequence you can act that's +there that's a very natural mono + + align:start position:0% +there that's a very natural mono + + + align:start position:0% +there that's a very natural mono +increasing sequence and a very natural + + align:start position:0% +increasing sequence and a very natural + + + align:start position:0% +increasing sequence and a very natural +mono decreasing sequence. + + align:start position:0% + + + + align:start position:0% + +Now let's try to prove the monotom + + align:start position:0% +Now let's try to prove the monotom + + + align:start position:0% +Now let's try to prove the monotom +convergence theorem and then let's get + + align:start position:0% +convergence theorem and then let's get + + + align:start position:0% +convergence theorem and then let's get +back to how to think about square root + + align:start position:0% +back to how to think about square root + + + align:start position:0% +back to how to think about square root +of two in a more intuitive way using + + align:start position:0% +of two in a more intuitive way using + + + align:start position:0% +of two in a more intuitive way using +this. + + align:start position:0% +this. + + + align:start position:0% +this. +[Applause] + + align:start position:0% + + + + align:start position:0% + +Okay. So now the proof of the monome. + + align:start position:0% + + + + align:start position:0% + +So we So now let me just remind you what + + align:start position:0% +So we So now let me just remind you what + + + align:start position:0% +So we So now let me just remind you what +we have. + + align:start position:0% +we have. + + + align:start position:0% +we have. +So I'm only going to prove one of the + + align:start position:0% +So I'm only going to prove one of the + + + align:start position:0% +So I'm only going to prove one of the +two versions of it where the sequence is + + align:start position:0% +two versions of it where the sequence is + + + align:start position:0% +two versions of it where the sequence is +monotum increasing because the other one + + align:start position:0% +monotum increasing because the other one + + + align:start position:0% +monotum increasing because the other one +is just proof is is just the same with + + align:start position:0% +is just proof is is just the same with + + + align:start position:0% +is just proof is is just the same with +obvious modification. So I'm assuming so + + align:start position:0% +obvious modification. So I'm assuming so + + + align:start position:0% +obvious modification. So I'm assuming so +this is the assumption. + + align:start position:0% +this is the assumption. + + + align:start position:0% +this is the assumption. +So this is the assumption. + + align:start position:0% + + + + align:start position:0% + +So, so this is just that the next + + align:start position:0% +So, so this is just that the next + + + align:start position:0% +So, so this is just that the next +element is larger equal to the previous + + align:start position:0% +element is larger equal to the previous + + + align:start position:0% +element is larger equal to the previous +one and they're all bounded by this a + + align:start position:0% +one and they're all bounded by this a + + + align:start position:0% +one and they're all bounded by this a +right + + align:start position:0% +right + + + align:start position:0% +right +now I take I we set + + align:start position:0% +now I take I we set + + + align:start position:0% +now I take I we set +little a equal to the soup + + align:start position:0% +little a equal to the soup + + + align:start position:0% +little a equal to the soup +uh of the a + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% + + + + align:start position:0% + +And I want to show we want to show + + align:start position:0% + + + + align:start position:0% + +that a converts to a. + + align:start position:0% +that a converts to a. + + + align:start position:0% +that a converts to a. +Now to do that what we need is we need + + align:start position:0% +Now to do that what we need is we need + + + align:start position:0% +Now to do that what we need is we need +this stuff about that for a given + + align:start position:0% +this stuff about that for a given + + + align:start position:0% +this stuff about that for a given +epsilon there exist a capital n. + + align:start position:0% +epsilon there exist a capital n. + + + align:start position:0% +epsilon there exist a capital n. +Okay. So now let me first make the + + align:start position:0% +Okay. So now let me first make the + + + align:start position:0% +Okay. So now let me first make the +observation + + align:start position:0% +observation + + + align:start position:0% +observation +that + + align:start position:0% + + + + align:start position:0% + +that the that the soup right so a here + + align:start position:0% +that the that the soup right so a here + + + align:start position:0% +that the that the soup right so a here +since + + align:start position:0% +since + + + align:start position:0% +since +a here is the soup + + align:start position:0% + + + + align:start position:0% + +it is + + align:start position:0% + + + + align:start position:0% + +right. Remember that the soup of a set + + align:start position:0% +right. Remember that the soup of a set + + + align:start position:0% +right. Remember that the soup of a set +is the smallest upper bound right so but + + align:start position:0% +is the smallest upper bound right so but + + + align:start position:0% +is the smallest upper bound right so but +since it is so it's partic so a is in + + align:start position:0% +since it is so it's partic so a is in + + + align:start position:0% +since it is so it's partic so a is in +particular an upper bound so you have + + align:start position:0% +particular an upper bound so you have + + + align:start position:0% +particular an upper bound so you have +that a n is less than a for all n + + align:start position:0% + + + + align:start position:0% + +since + + align:start position:0% +since + + + align:start position:0% +since +a is an upper bound. It's actually the + + align:start position:0% +a is an upper bound. It's actually the + + + align:start position:0% +a is an upper bound. It's actually the +smallest upper bound. But for this you + + align:start position:0% +smallest upper bound. But for this you + + + align:start position:0% +smallest upper bound. But for this you +just need it's a upper bound. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +So I'm going to look at a n sorry I'm + + align:start position:0% +So I'm going to look at a n sorry I'm + + + align:start position:0% +So I'm going to look at a n sorry I'm +going to look at a minus a n. + + align:start position:0% +going to look at a minus a n. + + + align:start position:0% +going to look at a minus a n. +And what I want to prove is that for a + + align:start position:0% +And what I want to prove is that for a + + + align:start position:0% +And what I want to prove is that for a +given epsilon if I'm sufficiently far + + align:start position:0% +given epsilon if I'm sufficiently far + + + align:start position:0% +given epsilon if I'm sufficiently far +out if I'm bigger than some capital if + + align:start position:0% +out if I'm bigger than some capital if + + + align:start position:0% +out if I'm bigger than some capital if +little n is bigger than some capital n + + align:start position:0% +little n is bigger than some capital n + + + align:start position:0% +little n is bigger than some capital n +then this here is less than epsilon + + align:start position:0% +then this here is less than epsilon + + + align:start position:0% +then this here is less than epsilon +right that's what I want to prove but + + align:start position:0% +right that's what I want to prove but + + + align:start position:0% +right that's what I want to prove but +this thing here you see this here I + + align:start position:0% +this thing here you see this here I + + + align:start position:0% +this thing here you see this here I +don't need the absolute value because I + + align:start position:0% +don't need the absolute value because I + + + align:start position:0% +don't need the absolute value because I +already know that this is bigger than + + align:start position:0% +already know that this is bigger than + + + align:start position:0% +already know that this is bigger than +that so I don't need the absolute value + + align:start position:0% +that so I don't need the absolute value + + + align:start position:0% +that so I don't need the absolute value +so I can just so this is what I want to + + align:start position:0% +so I can just so this is what I want to + + + align:start position:0% +so I can just so this is what I want to +prove that I want to prove that for + + align:start position:0% +prove that I want to prove that for + + + align:start position:0% +prove that I want to prove that for +given + + align:start position:0% +given + + + align:start position:0% +given +given epsilon greater than zero there + + align:start position:0% +given epsilon greater than zero there + + + align:start position:0% +given epsilon greater than zero there +exist. + + align:start position:0% + + + + align:start position:0% + +So maybe let me just write it a little + + align:start position:0% +So maybe let me just write it a little + + + align:start position:0% +So maybe let me just write it a little +larger here. So what I want to prove is + + align:start position:0% +larger here. So what I want to prove is + + + align:start position:0% +larger here. So what I want to prove is +that given + + align:start position:0% +that given + + + align:start position:0% +that given +epsilon greater than zero there exist + + align:start position:0% + + + + align:start position:0% + +a capital n such that + + align:start position:0% +a capital n such that + + + align:start position:0% +a capital n such that +if little n is bigger equal to this + + align:start position:0% +if little n is bigger equal to this + + + align:start position:0% +if little n is bigger equal to this +capital n then a minus a n which I know + + align:start position:0% +capital n then a minus a n which I know + + + align:start position:0% +capital n then a minus a n which I know +is positive I just need to prove that + + align:start position:0% +is positive I just need to prove that + + + align:start position:0% +is positive I just need to prove that +this is less than epsilon. + + align:start position:0% +this is less than epsilon. + + + align:start position:0% +this is less than epsilon. +Okay. + + align:start position:0% + + + + align:start position:0% + +Now, so now how do you do that? Well, + + align:start position:0% + + + + align:start position:0% + +I know. + + align:start position:0% +I know. + + + align:start position:0% +I know. +So, at the moment, I just use that A was + + align:start position:0% +So, at the moment, I just use that A was + + + align:start position:0% +So, at the moment, I just use that A was +an upper bound. Now, I'm going to use + + align:start position:0% +an upper bound. Now, I'm going to use + + + align:start position:0% +an upper bound. Now, I'm going to use +that is the least upper bound. + + align:start position:0% +that is the least upper bound. + + + align:start position:0% +that is the least upper bound. +So since + + align:start position:0% + + + + align:start position:0% + +a is the least upper bound + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% +then + + + align:start position:0% +then +uh a minus epsilon is not + + align:start position:0% +uh a minus epsilon is not + + + align:start position:0% +uh a minus epsilon is not +an upper bound. + + align:start position:0% + + + + align:start position:0% + +Right? A minus epsilon is not an upper + + align:start position:0% +Right? A minus epsilon is not an upper + + + align:start position:0% +Right? A minus epsilon is not an upper +bound. So this means that there must + + align:start position:0% +bound. So this means that there must + + + align:start position:0% +bound. So this means that there must +exist so + + align:start position:0% +exist so + + + align:start position:0% +exist so +there exist + + align:start position:0% + + + + align:start position:0% + +capital n so that a n is bigger or + + align:start position:0% +capital n so that a n is bigger or + + + align:start position:0% +capital n so that a n is bigger or +equal. So a capital n just this one here + + align:start position:0% +equal. So a capital n just this one here + + + align:start position:0% +equal. So a capital n just this one here +is bigger than a minus epsilon. Right? + + align:start position:0% +is bigger than a minus epsilon. Right? + + + align:start position:0% +is bigger than a minus epsilon. Right? +because otherwise it would have been an + + align:start position:0% +because otherwise it would have been an + + + align:start position:0% +because otherwise it would have been an +upper box but it's actually strictly but + + align:start position:0% +upper box but it's actually strictly but + + + align:start position:0% +upper box but it's actually strictly but +maybe I should strictly because I'll put + + align:start position:0% +maybe I should strictly because I'll put + + + align:start position:0% +maybe I should strictly because I'll put +it up. + + align:start position:0% +it up. + + + align:start position:0% +it up. +Okay, + + align:start position:0% +Okay, + + + align:start position:0% +Okay, +but I already know that this thing here + + align:start position:0% +but I already know that this thing here + + + align:start position:0% +but I already know that this thing here +is less than a + + align:start position:0% +is less than a + + + align:start position:0% +is less than a +so but and I also know in fact I know + + align:start position:0% +so but and I also know in fact I know + + + align:start position:0% +so but and I also know in fact I know +more than this. I know that this thing + + align:start position:0% +more than this. I know that this thing + + + align:start position:0% +more than this. I know that this thing +here is less or equal to a little n as + + align:start position:0% +here is less or equal to a little n as + + + align:start position:0% +here is less or equal to a little n as +long as little n is bigger than capital + + align:start position:0% +long as little n is bigger than capital + + + align:start position:0% +long as little n is bigger than capital +n. That was just because the sequence + + align:start position:0% +n. That was just because the sequence + + + align:start position:0% +n. That was just because the sequence +was increasing and all of them is + + align:start position:0% +was increasing and all of them is + + + align:start position:0% +was increasing and all of them is +smaller than this upper bound. So now + + align:start position:0% +smaller than this upper bound. So now + + + align:start position:0% +smaller than this upper bound. So now +you see that so here you have a all the + + align:start position:0% +you see that so here you have a all the + + + align:start position:0% +you see that so here you have a all the +elements a in lie to the left and if + + align:start position:0% +elements a in lie to the left and if + + + align:start position:0% +elements a in lie to the left and if +you're looking at just the one from a + + align:start position:0% +you're looking at just the one from a + + + align:start position:0% +you're looking at just the one from a +capital N outwards then here you have a + + align:start position:0% +capital N outwards then here you have a + + + align:start position:0% +capital N outwards then here you have a +minus epsilon and then they lie between + + align:start position:0% +minus epsilon and then they lie between + + + align:start position:0% +minus epsilon and then they lie between +this one here and that in particular + + align:start position:0% +this one here and that in particular + + + align:start position:0% +this one here and that in particular +they lie to the right of this and to the + + align:start position:0% +they lie to the right of this and to the + + + align:start position:0% +they lie to the right of this and to the +left of that. So this means that they're + + align:start position:0% +left of that. So this means that they're + + + align:start position:0% +left of that. So this means that they're +squeezed in this little interval and + + align:start position:0% +squeezed in this little interval and + + + align:start position:0% +squeezed in this little interval and +it's so this difference here this + + align:start position:0% +it's so this difference here this + + + align:start position:0% +it's so this difference here this +difference from here to here is + + align:start position:0% +difference from here to here is + + + align:start position:0% +difference from here to here is +certainly bounded by the distance to + + align:start position:0% +certainly bounded by the distance to + + + align:start position:0% +certainly bounded by the distance to +here which was epsilon + + align:start position:0% +here which was epsilon + + + align:start position:0% +here which was epsilon +right? + + align:start position:0% +right? + + + align:start position:0% +right? +So this proved that this in here is less + + align:start position:0% +So this proved that this in here is less + + + align:start position:0% +So this proved that this in here is less +than. + + align:start position:0% +than. + + + align:start position:0% +than. +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +And with obvious modification + + align:start position:0% +And with obvious modification + + + align:start position:0% +And with obvious modification +uh the proof of that if you take so this + + align:start position:0% +uh the proof of that if you take so this + + + align:start position:0% +uh the proof of that if you take so this +was an increasing sequence. The proof uh + + align:start position:0% +was an increasing sequence. The proof uh + + + align:start position:0% +was an increasing sequence. The proof uh +that if you have a decreasing sequence + + align:start position:0% +that if you have a decreasing sequence + + + align:start position:0% +that if you have a decreasing sequence +that is bounded right that that that the + + align:start position:0% +that is bounded right that that that the + + + align:start position:0% +that is bounded right that that that the +limit of that is the in proof with + + align:start position:0% +limit of that is the in proof with + + + align:start position:0% +limit of that is the in proof with +obvious changes is is know the same. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +So now let's come back to square root of + + align:start position:0% +So now let's come back to square root of + + + align:start position:0% +So now let's come back to square root of +two. Right. And so we have this idea + + align:start position:0% +two. Right. And so we have this idea + + + align:start position:0% +two. Right. And so we have this idea +that square<unk> two in a way the way + + align:start position:0% +that square<unk> two in a way the way + + + align:start position:0% +that square<unk> two in a way the way +you know to just get an idea about how + + align:start position:0% +you know to just get an idea about how + + + align:start position:0% +you know to just get an idea about how +large it is you think about it as uh you + + align:start position:0% +large it is you think about it as uh you + + + align:start position:0% +large it is you think about it as uh you +know you think about it as one and then + + align:start position:0% +know you think about it as one and then + + + align:start position:0% +know you think about it as one and then +a number of digits afterwards right + + align:start position:0% +a number of digits afterwards right + + + align:start position:0% +a number of digits afterwards right +that's a kind of approximation + + align:start position:0% +that's a kind of approximation + + + align:start position:0% +that's a kind of approximation +so so let's try to make this more + + align:start position:0% +so so let's try to make this more + + + align:start position:0% +so so let's try to make this more +precise + + align:start position:0% +precise + + + align:start position:0% +precise +Um + + align:start position:0% +Um + + + align:start position:0% +Um +[Applause] + + align:start position:0% + + + + align:start position:0% + +and so + + align:start position:0% +and so + + + align:start position:0% +and so +I'm going to look at a I'm going to + + align:start position:0% +I'm going to look at a I'm going to + + + align:start position:0% +I'm going to look at a I'm going to +define + + align:start position:0% +define + + + align:start position:0% +define +uh two sequence uh two sequences + + align:start position:0% +uh two sequence uh two sequences + + + align:start position:0% +uh two sequence uh two sequences +uh a n and bn sorry two. So we'll define + + align:start position:0% + + + + align:start position:0% + +two sequences + + align:start position:0% + + + + align:start position:0% + +a n and bn + + align:start position:0% +a n and bn + + + align:start position:0% +a n and bn +and a n will really be a n where + + align:start position:0% +and a n will really be a n where + + + align:start position:0% +and a n will really be a n where +where a n + + align:start position:0% +where a n + + + align:start position:0% +where a n +is going to be bn + + align:start position:0% +is going to be bn + + + align:start position:0% +is going to be bn +/ 10 to ^ nus one. + + align:start position:0% + + + + align:start position:0% + +Remember that anything to you know if + + align:start position:0% +Remember that anything to you know if + + + align:start position:0% +Remember that anything to you know if +it's 10 to the power zero by definition + + align:start position:0% +it's 10 to the power zero by definition + + + align:start position:0% +it's 10 to the power zero by definition +that's one. Okay. So this here in + + align:start position:0% +that's one. Okay. So this here in + + + align:start position:0% +that's one. Okay. So this here in +particular means that a + + align:start position:0% +particular means that a + + + align:start position:0% +particular means that a +a1 should be equal to b1. + + align:start position:0% + + + + align:start position:0% + +And we're going to define it like this. + + align:start position:0% + + + + align:start position:0% + +And we are + + align:start position:0% +And we are + + + align:start position:0% +And we are +going to define the BN. + + align:start position:0% +going to define the BN. + + + align:start position:0% +going to define the BN. +So and the sequences here the the so + + align:start position:0% +So and the sequences here the the so + + + align:start position:0% +So and the sequences here the the so +there would be some properties here is + + align:start position:0% +there would be some properties here is + + + align:start position:0% +there would be some properties here is +that the sequence + + align:start position:0% +that the sequence + + + align:start position:0% +that the sequence +uh sequence + + align:start position:0% + + + + align:start position:0% + +uh a is monotone + + align:start position:0% + + + + align:start position:0% + +increasing + + align:start position:0% + + + + align:start position:0% + +a just real numbers that it's monot + + align:start position:0% +a just real numbers that it's monot + + + align:start position:0% +a just real numbers that it's monot +increasing + + align:start position:0% +increasing + + + align:start position:0% +increasing +and um + + align:start position:0% +and um + + + align:start position:0% +and um +and uh and the a + + align:start position:0% + + + + align:start position:0% + +um is going to be defined to right so + + align:start position:0% +um is going to be defined to right so + + + align:start position:0% +um is going to be defined to right so +and and and a is defined like that sorry + + align:start position:0% + + + + align:start position:0% + +um and the bn + + align:start position:0% +um and the bn + + + align:start position:0% +um and the bn +and the bn are just + + align:start position:0% +and the bn are just + + + align:start position:0% +and the bn are just +natural numbers Okay. + + align:start position:0% +natural numbers Okay. + + + align:start position:0% +natural numbers Okay. +So, so a n is defined from bn. It's + + align:start position:0% +So, so a n is defined from bn. It's + + + align:start position:0% +So, so a n is defined from bn. It's +really a n that we are interested in, + + align:start position:0% +really a n that we are interested in, + + + align:start position:0% +really a n that we are interested in, +but bn is going to be a useful tool + + align:start position:0% +but bn is going to be a useful tool + + + align:start position:0% +but bn is going to be a useful tool +here. And so, + + align:start position:0% +here. And so, + + + align:start position:0% +here. And so, +and it's going to be and the bn to some + + align:start position:0% +and it's going to be and the bn to some + + + align:start position:0% +and it's going to be and the bn to some +extent is very simple because they're + + align:start position:0% +extent is very simple because they're + + + align:start position:0% +extent is very simple because they're +just natural numbers. + + align:start position:0% +just natural numbers. + + + align:start position:0% +just natural numbers. +So, now um so now we define + + align:start position:0% +So, now um so now we define + + + align:start position:0% +So, now um so now we define +bn. + + align:start position:0% +bn. + + + align:start position:0% +bn. +So bn + + align:start position:0% + + + + align:start position:0% + +is the largest + + align:start position:0% + + + + align:start position:0% + +natural number + + align:start position:0% + + + + align:start position:0% + +such that + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% +uh + + + align:start position:0% +uh +b² + + align:start position:0% + + + + align:start position:0% + +is bigger and less or equal to 2 uh * uh + + align:start position:0% +is bigger and less or equal to 2 uh * uh + + + align:start position:0% +is bigger and less or equal to 2 uh * uh + + align:start position:0% + + + align:start position:0% +to the power 2 n - 2. + + align:start position:0% +to the power 2 n - 2. + + + align:start position:0% +to the power 2 n - 2. +So that's how right so this here so this + + align:start position:0% +So that's how right so this here so this + + + align:start position:0% +So that's how right so this here so this +so the sets of natural number that is + + align:start position:0% +so the sets of natural number that is + + + align:start position:0% +so the sets of natural number that is +bounded by that right that's like a + + align:start position:0% +bounded by that right that's like a + + + align:start position:0% +bounded by that right that's like a +finite set so you just take the max of + + align:start position:0% +finite set so you just take the max of + + + align:start position:0% +finite set so you just take the max of +soup or whatever the max of that's it + + align:start position:0% +soup or whatever the max of that's it + + + align:start position:0% +soup or whatever the max of that's it +right it's just the max of that's it so + + align:start position:0% +right it's just the max of that's it so + + + align:start position:0% +right it's just the max of that's it so +that's a natural number + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and now + + align:start position:0% +and now + + + align:start position:0% +and now +and now again we + + align:start position:0% + + + + align:start position:0% + +right and then we define. So now we have + + align:start position:0% +right and then we define. So now we have + + + align:start position:0% +right and then we define. So now we have +the bs + + align:start position:0% +the bs + + + align:start position:0% +the bs +and then again a ends + + align:start position:0% + + + + align:start position:0% + +the a + + align:start position:0% +the a + + + align:start position:0% +the a +n are defined to be bn divided by 10 to + + align:start position:0% +n are defined to be bn divided by 10 to + + + align:start position:0% +n are defined to be bn divided by 10 to +the n minus one. Right? Right. And so + + align:start position:0% +the n minus one. Right? Right. And so + + + align:start position:0% +the n minus one. Right? Right. And so +again you see that and so right. So now + + align:start position:0% +again you see that and so right. So now + + + align:start position:0% +again you see that and so right. So now +the first thing you observe is that if n + + align:start position:0% +the first thing you observe is that if n + + + align:start position:0% +the first thing you observe is that if n +is equal to one + + align:start position:0% +is equal to one + + + align:start position:0% +is equal to one +if n is equal to one then this thing + + align:start position:0% +if n is equal to one then this thing + + + align:start position:0% +if n is equal to one then this thing +here is zero so this means this has one + + align:start position:0% +here is zero so this means this has one + + + align:start position:0% +here is zero so this means this has one +so it's the largest natural number so + + align:start position:0% +so it's the largest natural number so + + + align:start position:0% +so it's the largest natural number so +that the square is less than two so this + + align:start position:0% +that the square is less than two so this + + + align:start position:0% +that the square is less than two so this +means that bn + + align:start position:0% +means that bn + + + align:start position:0% +means that bn +so n= to one bn is equal to one and + + align:start position:0% +so n= to one bn is equal to one and + + + align:start position:0% +so n= to one bn is equal to one and +because this thing here is also + + align:start position:0% +because this thing here is also + + + align:start position:0% +because this thing here is also +zero. So this the denominator is is one. + + align:start position:0% +zero. So this the denominator is is one. + + + align:start position:0% +zero. So this the denominator is is one. +So a n a1 sorry a1 is one. b1 is one and + + align:start position:0% +So a n a1 sorry a1 is one. b1 is one and + + + align:start position:0% +So a n a1 sorry a1 is one. b1 is one and +a1 has to be the same as b1. And so + + align:start position:0% +a1 has to be the same as b1. And so + + + align:start position:0% +a1 has to be the same as b1. And so +that's also one. + + align:start position:0% +that's also one. + + + align:start position:0% +that's also one. +Okay. So that's how it starts. + + align:start position:0% +Okay. So that's how it starts. + + + align:start position:0% +Okay. So that's how it starts. +And now what we want to prove is that um + + align:start position:0% +And now what we want to prove is that um + + + align:start position:0% +And now what we want to prove is that um +we want to prove that the sequence a n + + align:start position:0% +we want to prove that the sequence a n + + + align:start position:0% +we want to prove that the sequence a n +is monotm increasing right we want to + + align:start position:0% +is monotm increasing right we want to + + + align:start position:0% +is monotm increasing right we want to +prove that a end is monotum increasing + + align:start position:0% +prove that a end is monotum increasing + + + align:start position:0% +prove that a end is monotum increasing +so let's just try to understand that + + align:start position:0% +so let's just try to understand that + + + align:start position:0% +so let's just try to understand that +right and so again for mono increasing + + align:start position:0% +right and so again for mono increasing + + + align:start position:0% +right and so again for mono increasing +you just need to compare two consecutive + + align:start position:0% +you just need to compare two consecutive + + + align:start position:0% +you just need to compare two consecutive +elements right so so we want to show + + align:start position:0% +elements right so so we want to show + + + align:start position:0% +elements right so so we want to show +so so this here remember that there's a + + align:start position:0% +so so this here remember that there's a + + + align:start position:0% +so so this here remember that there's a +kind of you know there's ways to write a + + align:start position:0% +kind of you know there's ways to write a + + + align:start position:0% +kind of you know there's ways to write a +formal proof and then there's like + + align:start position:0% +formal proof and then there's like + + + align:start position:0% +formal proof and then there's like +things you have on the scrap paper to + + align:start position:0% +things you have on the scrap paper to + + + align:start position:0% +things you have on the scrap paper to +get the idea. So this is would be what + + align:start position:0% +get the idea. So this is would be what + + + align:start position:0% +get the idea. So this is would be what +we're going on may maybe the first + + align:start position:0% +we're going on may maybe the first + + + align:start position:0% +we're going on may maybe the first +statement is so we want to show this you + + align:start position:0% +statement is so we want to show this you + + + align:start position:0% +statement is so we want to show this you +could certainly put as part of the proof + + align:start position:0% +could certainly put as part of the proof + + + align:start position:0% +could certainly put as part of the proof +want to show + + align:start position:0% +want to show + + + align:start position:0% +want to show +that + + align:start position:0% +that + + + align:start position:0% +that +a n is less or equal to a n + one + + align:start position:0% + + + + align:start position:0% + +and so this is equivalent + + align:start position:0% + + + + align:start position:0% + +to + + align:start position:0% + + + + align:start position:0% + +that right? So a n since a n here is + + align:start position:0% +that right? So a n since a n here is + + + align:start position:0% +that right? So a n since a n here is +equal to bn / 10 ^ n minus 2. You want + + align:start position:0% +equal to bn / 10 ^ n minus 2. You want + + + align:start position:0% +equal to bn / 10 ^ n minus 2. You want +to prove that this thing here is less + + align:start position:0% +to prove that this thing here is less + + + align:start position:0% +to prove that this thing here is less +than a n + 1 which is b n + 1 + + align:start position:0% +than a n + 1 which is b n + 1 + + + align:start position:0% +than a n + 1 which is b n + 1 +over 10 to the n + 1 - one. So this here + + align:start position:0% +over 10 to the n + 1 - one. So this here + + + align:start position:0% +over 10 to the n + 1 - one. So this here +is b n + 1 over 10 uh to the power n. + + align:start position:0% +is b n + 1 over 10 uh to the power n. + + + align:start position:0% +is b n + 1 over 10 uh to the power n. +That's what you want to prove. + + align:start position:0% +That's what you want to prove. + + + align:start position:0% +That's what you want to prove. +So we want to show so so you see that + + align:start position:0% + + + + align:start position:0% + +we want to show so this is what we want + + align:start position:0% +we want to show so this is what we want + + + align:start position:0% +we want to show so this is what we want +to prove that this thing here is less + + align:start position:0% +to prove that this thing here is less + + + align:start position:0% +to prove that this thing here is less +than this. If you multiply by 10 to the^ + + align:start position:0% +than this. If you multiply by 10 to the^ + + + align:start position:0% +than this. If you multiply by 10 to the^ +n on both sides then you get over here + + align:start position:0% +n on both sides then you get over here + + + align:start position:0% +n on both sides then you get over here +and after you reduce it you get 10. So + + align:start position:0% +and after you reduce it you get 10. So + + + align:start position:0% +and after you reduce it you get 10. So +en so need to show + + align:start position:0% + + + + align:start position:0% + +needs to show + + align:start position:0% + + + + align:start position:0% + +that 10 + + align:start position:0% +that 10 + + + align:start position:0% +that 10 +bn + + align:start position:0% +bn + + + align:start position:0% +bn +is less or equal to bn + one + + align:start position:0% +is less or equal to bn + one + + + align:start position:0% +is less or equal to bn + one +right that's what we need to prove right + + align:start position:0% +right that's what we need to prove right + + + align:start position:0% +right that's what we need to prove right +and again this just comes from that you + + align:start position:0% +and again this just comes from that you + + + align:start position:0% +and again this just comes from that you +we want to prove forget about the a now + + align:start position:0% +we want to prove forget about the a now + + + align:start position:0% +we want to prove forget about the a now +you can just think about that we need to + + align:start position:0% +you can just think about that we need to + + + align:start position:0% +you can just think about that we need to +prove that this in here is less than + + align:start position:0% +prove that this in here is less than + + + align:start position:0% +prove that this in here is less than +this multiply over by 10 to the n on + + align:start position:0% +this multiply over by 10 to the n on + + + align:start position:0% +this multiply over by 10 to the n on +both sides then there's still 10 * bn + + align:start position:0% +both sides then there's still 10 * bn + + + align:start position:0% +both sides then there's still 10 * bn +left and here it's just b + + align:start position:0% +left and here it's just b + + + align:start position:0% +left and here it's just b +okay so we need to show this one here + + align:start position:0% +okay so we need to show this one here + + + align:start position:0% +okay so we need to show this one here +right and so if I was to write it down I + + align:start position:0% +right and so if I was to write it down I + + + align:start position:0% +right and so if I was to write it down I +would probably have some of this on + + align:start position:0% +would probably have some of this on + + + align:start position:0% +would probably have some of this on +scrap paper and then I would instead + + align:start position:0% +scrap paper and then I would instead + + + align:start position:0% +scrap paper and then I would instead +sort of establish this here first and + + align:start position:0% +sort of establish this here first and + + + align:start position:0% +sort of establish this here first and +then say therefore you know and then + + align:start position:0% +then say therefore you know and then + + + align:start position:0% +then say therefore you know and then +I'll conclude why you So you but but of + + align:start position:0% +I'll conclude why you So you but but of + + + align:start position:0% +I'll conclude why you So you but but of +course that's not the way you're + + align:start position:0% +course that's not the way you're + + + align:start position:0% +course that's not the way you're +thinking about it right I mean you first + + align:start position:0% +thinking about it right I mean you first + + + align:start position:0% +thinking about it right I mean you first +try to analyze what you have to prove + + align:start position:0% +try to analyze what you have to prove + + + align:start position:0% +try to analyze what you have to prove +and then once you know that then you try + + align:start position:0% +and then once you know that then you try + + + align:start position:0% +and then once you know that then you try +to write it down nicely + + align:start position:0% +to write it down nicely + + + align:start position:0% +to write it down nicely +okay so so we need to prove this here + + align:start position:0% +okay so so we need to prove this here + + + align:start position:0% +okay so so we need to prove this here +and so now + + align:start position:0% +and so now + + + align:start position:0% +and so now +uh right so now the thing is that we + + align:start position:0% +uh right so now the thing is that we + + + align:start position:0% +uh right so now the thing is that we +have + + align:start position:0% +have + + + align:start position:0% +have +we have that so The definition of bn + + align:start position:0% +we have that so The definition of bn + + + align:start position:0% +we have that so The definition of bn +which is right here that's the + + align:start position:0% +which is right here that's the + + + align:start position:0% +which is right here that's the +definition of bn but let me copy it over + + align:start position:0% +definition of bn but let me copy it over + + + align:start position:0% +definition of bn but let me copy it over +here. So we know that bn squared is less + + align:start position:0% +here. So we know that bn squared is less + + + align:start position:0% +here. So we know that bn squared is less +or equal to it's the largest integer. So + + align:start position:0% +or equal to it's the largest integer. So + + + align:start position:0% +or equal to it's the largest integer. So +that you have this in here, + + align:start position:0% +that you have this in here, + + + align:start position:0% +that you have this in here, +right? + + align:start position:0% +right? + + + align:start position:0% +right? +But this means that if you're looking at + + align:start position:0% +But this means that if you're looking at + + + align:start position:0% +But this means that if you're looking at +10 bn, that's still an integer. And if + + align:start position:0% +10 bn, that's still an integer. And if + + + align:start position:0% +10 bn, that's still an integer. And if +you square this here, right? Then this + + align:start position:0% +you square this here, right? Then this + + + align:start position:0% +you square this here, right? Then this +is the same as 100 + + align:start position:0% +is the same as 100 + + + align:start position:0% +is the same as 100 +times bn squared. And so that's that + + align:start position:0% +times bn squared. And so that's that + + + align:start position:0% +times bn squared. And so that's that +actually has to be less than 100 * this. + + align:start position:0% +actually has to be less than 100 * this. + + + align:start position:0% +actually has to be less than 100 * this. +So this kills those uh I mean so it just + + align:start position:0% +So this kills those uh I mean so it just + + + align:start position:0% +So this kills those uh I mean so it just +becomes less or equal to two 10 to the + + align:start position:0% +becomes less or equal to two 10 to the + + + align:start position:0% +becomes less or equal to two 10 to the +2n + + align:start position:0% +2n + + + align:start position:0% +2n +right like that + + align:start position:0% +right like that + + + align:start position:0% +right like that +and this here you can also write as 2 + + align:start position:0% +and this here you can also write as 2 + + + align:start position:0% +and this here you can also write as 2 +to the 10 * 10 to ^ 2 n + 1 - 2 right + + align:start position:0% +to the 10 * 10 to ^ 2 n + 1 - 2 right + + + align:start position:0% +to the 10 * 10 to ^ 2 n + 1 - 2 right +but now you see that bn so this so this + + align:start position:0% +but now you see that bn so this so this + + + align:start position:0% +but now you see that bn so this so this +so 10 bn is an integer and it has this + + align:start position:0% +so 10 bn is an integer and it has this + + + align:start position:0% +so 10 bn is an integer and it has this +property but bn + one was supposed to be + + align:start position:0% +property but bn + one was supposed to be + + + align:start position:0% +property but bn + one was supposed to be +the largest integer so that the square + + align:start position:0% +the largest integer so that the square + + + align:start position:0% +the largest integer so that the square +here is less than 2 * 10 to to 2 n + 1 - + + align:start position:0% +here is less than 2 * 10 to to 2 n + 1 - + + + align:start position:0% +here is less than 2 * 10 to to 2 n + 1 - +2 you see that bn + one is a is the + + align:start position:0% +2 you see that bn + one is a is the + + + align:start position:0% +2 you see that bn + one is a is the +largest one with this property so you + + align:start position:0% +largest one with this property so you + + + align:start position:0% +largest one with this property so you +conclude that so since + + align:start position:0% +conclude that so since + + + align:start position:0% +conclude that so since +bn + one is the largest such + + align:start position:0% + + + + align:start position:0% + +and both are integers + + align:start position:0% +and both are integers + + + align:start position:0% +and both are integers +and and bn is is an integer + + align:start position:0% +and and bn is is an integer + + + align:start position:0% +and and bn is is an integer +then uh bn + one must be bigger equal to + + align:start position:0% +then uh bn + one must be bigger equal to + + + align:start position:0% +then uh bn + one must be bigger equal to +bn + + align:start position:0% +bn + + + align:start position:0% +bn +uh must be bigger than 10 * bn right + + align:start position:0% + + + + align:start position:0% + +and that's exactly what we want to prove + + align:start position:0% +and that's exactly what we want to prove + + + align:start position:0% +and that's exactly what we want to prove +right that that uh bn + one was bigger + + align:start position:0% +right that that uh bn + one was bigger + + + align:start position:0% +right that that uh bn + one was bigger +than bn. + + align:start position:0% +than bn. + + + align:start position:0% +than bn. +So we now have that the sequence a + + align:start position:0% +So we now have that the sequence a + + + align:start position:0% +So we now have that the sequence a +defined this slightly cryptical way but + + align:start position:0% +defined this slightly cryptical way but + + + align:start position:0% +defined this slightly cryptical way but +really it's not I mean it sounds maybe + + align:start position:0% +really it's not I mean it sounds maybe + + + align:start position:0% +really it's not I mean it sounds maybe +cryptical but it's just to instead of + + align:start position:0% +cryptical but it's just to instead of + + + align:start position:0% +cryptical but it's just to instead of +using somehow digital numbers you just + + align:start position:0% +using somehow digital numbers you just + + + align:start position:0% +using somehow digital numbers you just +multiply you're just thinking about you + + align:start position:0% +multiply you're just thinking about you + + + align:start position:0% +multiply you're just thinking about you +want this and that many uh by so uh like + + align:start position:0% +want this and that many uh by so uh like + + + align:start position:0% +want this and that many uh by so uh like +the n is referring to the number of + + align:start position:0% +the n is referring to the number of + + + align:start position:0% +the n is referring to the number of +digits but including the digit that is + + align:start position:0% +digits but including the digit that is + + + align:start position:0% +digits but including the digit that is +for the the point right so it's actually + + align:start position:0% +for the the point right so it's actually + + + align:start position:0% +for the the point right so it's actually +not very cryptical but it maybe sounds a + + align:start position:0% +not very cryptical but it maybe sounds a + + + align:start position:0% +not very cryptical but it maybe sounds a +little formal here okay so we have a n + + align:start position:0% +little formal here okay so we have a n + + + align:start position:0% +little formal here okay so we have a n +is a increasing sequence okay now why is + + align:start position:0% +is a increasing sequence okay now why is + + + align:start position:0% +is a increasing sequence okay now why is +a n bounded right + + align:start position:0% +a n bounded right + + + align:start position:0% +a n bounded right +so but the a is defined from the bn + + align:start position:0% +so but the a is defined from the bn + + + align:start position:0% +so but the a is defined from the bn +so in order to show that a n is bounded + + align:start position:0% +so in order to show that a n is bounded + + + align:start position:0% +so in order to show that a n is bounded +you have to figure out you have to + + align:start position:0% +you have to figure out you have to + + + align:start position:0% +you have to figure out you have to +figure out what is a bound for the BN + + align:start position:0% +figure out what is a bound for the BN + + + align:start position:0% +figure out what is a bound for the BN +right but you have this here bn is the + + align:start position:0% +right but you have this here bn is the + + + align:start position:0% +right but you have this here bn is the +largest such number if I take if I take + + align:start position:0% +largest such number if I take if I take + + + align:start position:0% +largest such number if I take if I take +two * 10 ^ n minus one suppose I take + + align:start position:0% +two * 10 ^ n minus one suppose I take + + + align:start position:0% +two * 10 ^ n minus one suppose I take +this number here right and I square it + + align:start position:0% +this number here right and I square it + + + align:start position:0% +this number here right and I square it +this is a definitely a integer I square + + align:start position:0% +this is a definitely a integer I square + + + align:start position:0% +this is a definitely a integer I square +it then I'm getting 4 * 10 ^ 2 n - 2 + + align:start position:0% +it then I'm getting 4 * 10 ^ 2 n - 2 + + + align:start position:0% +it then I'm getting 4 * 10 ^ 2 n - 2 +right so this thing here This here is + + align:start position:0% +right so this thing here This here is + + + align:start position:0% +right so this thing here This here is +the same as over here but it's now four. + + align:start position:0% +the same as over here but it's now four. + + + align:start position:0% +the same as over here but it's now four. +So this number here would not be allowed + + align:start position:0% +So this number here would not be allowed + + + align:start position:0% +So this number here would not be allowed +as a bn. In fact it would be larger than + + align:start position:0% +as a bn. In fact it would be larger than + + + align:start position:0% +as a bn. In fact it would be larger than +bn. Right? So this here so bn is less + + align:start position:0% +bn. Right? So this here so bn is less + + + align:start position:0% +bn. Right? So this here so bn is less +than 2 to the^ 10 to the n minus one. + + align:start position:0% +than 2 to the^ 10 to the n minus one. + + + align:start position:0% +than 2 to the^ 10 to the n minus one. +Right? + + align:start position:0% + + + + align:start position:0% + +So this means that a n + + align:start position:0% +So this means that a n + + + align:start position:0% +So this means that a n +which is equal to bn over 10 ^ n minus + + align:start position:0% +which is equal to bn over 10 ^ n minus + + + align:start position:0% +which is equal to bn over 10 ^ n minus +one but this is now you see less or + + align:start position:0% +one but this is now you see less or + + + align:start position:0% +one but this is now you see less or +equal to two right + + align:start position:0% +equal to two right + + + align:start position:0% +equal to two right +so the sequence a n that we have defined + + align:start position:0% +so the sequence a n that we have defined + + + align:start position:0% +so the sequence a n that we have defined +is uh as you would have expected they + + align:start position:0% +is uh as you would have expected they + + + align:start position:0% +is uh as you would have expected they +are they're increasing because they + + align:start position:0% +are they're increasing because they + + + align:start position:0% +are they're increasing because they +really define the way they're really if + + align:start position:0% +really define the way they're really if + + + align:start position:0% +really define the way they're really if +you think about it is really defined to + + align:start position:0% +you think about it is really defined to + + + align:start position:0% +you think about it is really defined to +take you know the number of digits sort + + align:start position:0% +take you know the number of digits sort + + + align:start position:0% +take you know the number of digits sort +of it's going to be like the number of + + align:start position:0% +of it's going to be like the number of + + + align:start position:0% +of it's going to be like the number of +digits in square roo including the one + + align:start position:0% +digits in square roo including the one + + + align:start position:0% +digits in square roo including the one +the starting one right + + align:start position:0% +the starting one right + + + align:start position:0% +the starting one right +so and so + + align:start position:0% +so and so + + + align:start position:0% +so and so +um and so they all are going to be less + + align:start position:0% +um and so they all are going to be less + + + align:start position:0% +um and so they all are going to be less +than two right okay now + + align:start position:0% +than two right okay now + + + align:start position:0% +than two right okay now +let's try to + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% + + + + align:start position:0% + +Right. So now um we have so we have that + + align:start position:0% +Right. So now um we have so we have that + + + align:start position:0% +Right. So now um we have so we have that +a n is an increasing sequence and is + + align:start position:0% +a n is an increasing sequence and is + + + align:start position:0% +a n is an increasing sequence and is +bounded. + + align:start position:0% + + + + align:start position:0% + +So a end here uh is convergent + + align:start position:0% + + + + align:start position:0% + +by the monitor + + align:start position:0% + + + + align:start position:0% + +uh convergence here. + + align:start position:0% + + + + align:start position:0% + +Right? So the a is convergent by the + + align:start position:0% +Right? So the a is convergent by the + + + align:start position:0% +Right? So the a is convergent by the +monotone convergence. + + align:start position:0% +monotone convergence. + + + align:start position:0% +monotone convergence. +But now if I'm looking at a n squ a n + + align:start position:0% +But now if I'm looking at a n squ a n + + + align:start position:0% +But now if I'm looking at a n squ a n +squ well a n squ it's the same as a end + + align:start position:0% +squ well a n squ it's the same as a end + + + align:start position:0% +squ well a n squ it's the same as a end +obviously times a n right but um but um + + align:start position:0% +obviously times a n right but um but um + + + align:start position:0% +obviously times a n right but um but um +but uh a n by definition was bn divided + + align:start position:0% +but uh a n by definition was bn divided + + + align:start position:0% +but uh a n by definition was bn divided +by 10 + + align:start position:0% +by 10 + + + align:start position:0% +by 10 +uh uh 10 to the power uh n - one right + + align:start position:0% +uh uh 10 to the power uh n - one right + + + align:start position:0% +uh uh 10 to the power uh n - one right +and so I can write like this + + align:start position:0% +and so I can write like this + + + align:start position:0% +and so I can write like this +10 ^ n minus one and so you see that you + + align:start position:0% +10 ^ n minus one and so you see that you + + + align:start position:0% +10 ^ n minus one and so you see that you +can write this as bn^ squ and then these + + align:start position:0% +can write this as bn^ squ and then these + + + align:start position:0% +can write this as bn^ squ and then these +here combines to 2 n minus 2 right and + + align:start position:0% +here combines to 2 n minus 2 right and + + + align:start position:0% +here combines to 2 n minus 2 right and +by assumption + + align:start position:0% +by assumption + + + align:start position:0% +by assumption +if you divide by this here this thing + + align:start position:0% +if you divide by this here this thing + + + align:start position:0% +if you divide by this here this thing +here is lesser equal to two + + align:start position:0% + + + + align:start position:0% + +so you have that. So you have that a n + + align:start position:0% +so you have that. So you have that a n + + + align:start position:0% +so you have that. So you have that a n +converts to a. And if you want to think + + align:start position:0% +converts to a. And if you want to think + + + align:start position:0% +converts to a. And if you want to think +about it, you think about this sequence + + align:start position:0% +about it, you think about this sequence + + + align:start position:0% +about it, you think about this sequence +again. + + align:start position:0% +again. + + + align:start position:0% +again. +And so now you know that a n by this uh + + align:start position:0% +And so now you know that a n by this uh + + + align:start position:0% +And so now you know that a n by this uh +by the product rule for sequences a n + + align:start position:0% +by the product rule for sequences a n + + + align:start position:0% +by the product rule for sequences a n +times a n the sequence times itself is + + align:start position:0% +times a n the sequence times itself is + + + align:start position:0% +times a n the sequence times itself is +converging to a n square a square. + + align:start position:0% +converging to a n square a square. + + + align:start position:0% +converging to a n square a square. +Right? + + align:start position:0% +Right? + + + align:start position:0% +Right? +And this thing here because they are + + align:start position:0% +And this thing here because they are + + + align:start position:0% +And this thing here because they are +because each of these squares here each + + align:start position:0% +because each of these squares here each + + + align:start position:0% +because each of these squares here each +of them is less or equal to two then the + + align:start position:0% +of them is less or equal to two then the + + + align:start position:0% +of them is less or equal to two then the +limit must be lesser equal to two. + + align:start position:0% + + + + align:start position:0% + +What I want to prove now is that this a + + align:start position:0% +What I want to prove now is that this a + + + align:start position:0% +What I want to prove now is that this a +that we get as a limit that the square + + align:start position:0% +that we get as a limit that the square + + + align:start position:0% +that we get as a limit that the square +is in fact equal to two. So I want to + + align:start position:0% +is in fact equal to two. So I want to + + + align:start position:0% +is in fact equal to two. So I want to +show that it's the square is so I have + + align:start position:0% +show that it's the square is so I have + + + align:start position:0% +show that it's the square is so I have +so I have so you know when we're doing + + align:start position:0% +so I have so you know when we're doing + + + align:start position:0% +so I have so you know when we're doing +it this this is one more proof of that + + align:start position:0% +it this this is one more proof of that + + + align:start position:0% +it this this is one more proof of that +square root of two is a real number but + + align:start position:0% +square root of two is a real number but + + + align:start position:0% +square root of two is a real number but +this is sort of in a way how you think + + align:start position:0% +this is sort of in a way how you think + + + align:start position:0% +this is sort of in a way how you think +about it in terms of the uh decimals + + align:start position:0% +about it in terms of the uh decimals + + + align:start position:0% +about it in terms of the uh decimals +right + + align:start position:0% +right + + + align:start position:0% +right +and so we have this sequence a n and we + + align:start position:0% +and so we have this sequence a n and we + + + align:start position:0% +and so we have this sequence a n and we +have proven that it's converging to some + + align:start position:0% +have proven that it's converging to some + + + align:start position:0% +have proven that it's converging to some +a and we've shown that this a here has a + + align:start position:0% +a and we've shown that this a here has a + + + align:start position:0% +a and we've shown that this a here has a +property that is lesser a squ is lesser + + align:start position:0% +property that is lesser a squ is lesser + + + align:start position:0% +property that is lesser a squ is lesser +equal to true. So I want to prove so I + + align:start position:0% +equal to true. So I want to prove so I + + + align:start position:0% +equal to true. So I want to prove so I +want to show + + align:start position:0% + + + + align:start position:0% + +that a and + + align:start position:0% +that a and + + + align:start position:0% +that a and +that sorry that a squ is actually equal + + align:start position:0% +that sorry that a squ is actually equal + + + align:start position:0% +that sorry that a squ is actually equal +to not one but two right that's what I + + align:start position:0% +to not one but two right that's what I + + + align:start position:0% +to not one but two right that's what I +want to prove right and but I already + + align:start position:0% +want to prove right and but I already + + + align:start position:0% +want to prove right and but I already +proven that a squ is less or equal to + + align:start position:0% +proven that a squ is less or equal to + + + align:start position:0% +proven that a squ is less or equal to +two so enough + + align:start position:0% + + + + align:start position:0% + +to show + + align:start position:0% +to show + + + align:start position:0% +to show +that a squ is bigger = to + + align:start position:0% + + + + align:start position:0% + +okay so let's try to do that + + align:start position:0% + + + + align:start position:0% + +and I'm going to use this is going to be + + align:start position:0% +and I'm going to use this is going to be + + + align:start position:0% +and I'm going to use this is going to be +another illustration of the algebraic + + align:start position:0% +another illustration of the algebraic + + + align:start position:0% +another illustration of the algebraic +rules for sequences + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +I I haven't really I mean I I here now I + + align:start position:0% +I I haven't really I mean I I here now I + + + align:start position:0% +I I haven't really I mean I I here now I +really you know to prove + + align:start position:0% +really you know to prove + + + align:start position:0% +really you know to prove +that is less or equal to two. I didn't + + align:start position:0% +that is less or equal to two. I didn't + + + align:start position:0% +that is less or equal to two. I didn't +use fully the definition of the A + + align:start position:0% +use fully the definition of the A + + + align:start position:0% +use fully the definition of the A +because I didn't use I didn't really use + + align:start position:0% +because I didn't use I didn't really use + + + align:start position:0% +because I didn't use I didn't really use +that it was the largest such that A was + + align:start position:0% +that it was the largest such that A was + + + align:start position:0% +that it was the largest such that A was +defined in terms of BN where BN was the + + align:start position:0% +defined in terms of BN where BN was the + + + align:start position:0% +defined in terms of BN where BN was the +largest such uh such um + + align:start position:0% + + + + align:start position:0% + +such number + + align:start position:0% +such number + + + align:start position:0% +such number +and so if I'm looking at + + align:start position:0% +and so if I'm looking at + + + align:start position:0% +and so if I'm looking at +suppose now I'm looking at BN + + align:start position:0% +suppose now I'm looking at BN + + + align:start position:0% +suppose now I'm looking at BN +and I'm adding one + + align:start position:0% +and I'm adding one + + + align:start position:0% +and I'm adding one +and I'm squaring it. Right? + + align:start position:0% +and I'm squaring it. Right? + + + align:start position:0% +and I'm squaring it. Right? +Well, this here cannot also be smaller + + align:start position:0% +Well, this here cannot also be smaller + + + align:start position:0% +Well, this here cannot also be smaller +than this here because then then then + + align:start position:0% +than this here because then then then + + + align:start position:0% +than this here because then then then +the BN should have been this thing here, + + align:start position:0% +the BN should have been this thing here, + + + align:start position:0% +the BN should have been this thing here, +right? So, this here must actually be + + align:start position:0% +right? So, this here must actually be + + + align:start position:0% +right? So, this here must actually be +strictly larger than 2 10 ^ 2nus 2. + + align:start position:0% +strictly larger than 2 10 ^ 2nus 2. + + + align:start position:0% +strictly larger than 2 10 ^ 2nus 2. +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +And so now you write, + + align:start position:0% +And so now you write, + + + align:start position:0% +And so now you write, +you know, you just divide by by this + + align:start position:0% +you know, you just divide by by this + + + align:start position:0% +you know, you just divide by by this +here on both sides. So you have b n + 1 + + align:start position:0% +here on both sides. So you have b n + 1 + + + align:start position:0% +here on both sides. So you have b n + 1 +squared and you divide it by 10 to the + + align:start position:0% +squared and you divide it by 10 to the + + + align:start position:0% +squared and you divide it by 10 to the +power 2 n - 2. So you know that this + + align:start position:0% +power 2 n - 2. So you know that this + + + align:start position:0% +power 2 n - 2. So you know that this +thing is bigger than two. + + align:start position:0% +thing is bigger than two. + + + align:start position:0% +thing is bigger than two. +So now but you can write this in here. + + align:start position:0% +So now but you can write this in here. + + + align:start position:0% +So now but you can write this in here. +This denominator 10 ^ 2 nus 2 you can + + align:start position:0% +This denominator 10 ^ 2 nus 2 you can + + + align:start position:0% +This denominator 10 ^ 2 nus 2 you can +write as 10 ^ n -1 * 10 ^ n minus one. + + align:start position:0% +write as 10 ^ n -1 * 10 ^ n minus one. + + + align:start position:0% +write as 10 ^ n -1 * 10 ^ n minus one. +So in this way you can split this up and + + align:start position:0% +So in this way you can split this up and + + + align:start position:0% +So in this way you can split this up and +you can write it as bn + 1 over uh 10 ^ + + align:start position:0% +you can write it as bn + 1 over uh 10 ^ + + + align:start position:0% +you can write it as bn + 1 over uh 10 ^ +n minus one + + align:start position:0% +n minus one + + + align:start position:0% +n minus one +and then times itself. + + align:start position:0% +and then times itself. + + + align:start position:0% +and then times itself. +This is is just to make sure that it's + + align:start position:0% +This is is just to make sure that it's + + + align:start position:0% +This is is just to make sure that it's +not + + align:start position:0% +not + + + align:start position:0% +not +it's BN and then to the BN you're adding + + align:start position:0% +it's BN and then to the BN you're adding + + + align:start position:0% +it's BN and then to the BN you're adding +one. + + align:start position:0% +one. + + + align:start position:0% +one. +So like that + + align:start position:0% +So like that + + + align:start position:0% +So like that +you write like that. + + align:start position:0% +you write like that. + + + align:start position:0% +you write like that. +But you see this thing here, this is + + align:start position:0% +But you see this thing here, this is + + + align:start position:0% +But you see this thing here, this is +this here, this thing here. You can + + align:start position:0% +this here, this thing here. You can + + + align:start position:0% +this here, this thing here. You can +split the fraction up. You can write it + + align:start position:0% +split the fraction up. You can write it + + + align:start position:0% +split the fraction up. You can write it +as bn + + align:start position:0% +as bn + + + align:start position:0% +as bn +uh over 10 ^ n minus one. And then you + + align:start position:0% +uh over 10 ^ n minus one. And then you + + + align:start position:0% +uh over 10 ^ n minus one. And then you +can add 1 / 10 ^ nus1 + + align:start position:0% +can add 1 / 10 ^ nus1 + + + align:start position:0% +can add 1 / 10 ^ nus1 +and then you can multiply that by + + align:start position:0% +and then you can multiply that by + + + align:start position:0% +and then you can multiply that by +itself. Right? You can write it like + + align:start position:0% +itself. Right? You can write it like + + + align:start position:0% +itself. Right? You can write it like +that. + + align:start position:0% + + + + align:start position:0% + +Right? But now now + + align:start position:0% +Right? But now now + + + align:start position:0% +Right? But now now +you see now I can write this in here + + align:start position:0% +you see now I can write this in here + + + align:start position:0% +you see now I can write this in here +as + + align:start position:0% +as + + + align:start position:0% +as +so now I can think about it in a + + align:start position:0% +so now I can think about it in a + + + align:start position:0% +so now I can think about it in a +slightly different way. So I have that. + + align:start position:0% +slightly different way. So I have that. + + + align:start position:0% +slightly different way. So I have that. +So so I can write this thing here. This + + align:start position:0% +So so I can write this thing here. This + + + align:start position:0% +So so I can write this thing here. This +thing here is just that is the + + align:start position:0% +thing here is just that is the + + + align:start position:0% +thing here is just that is the +definition of a n. + + align:start position:0% +definition of a n. + + + align:start position:0% +definition of a n. +Right? + + align:start position:0% +Right? + + + align:start position:0% +Right? +So I can say so what I have here is that + + align:start position:0% +So I can say so what I have here is that + + + align:start position:0% +So I can say so what I have here is that +a n + 1 / 10 ^ n minus one times itself + + align:start position:0% +a n + 1 / 10 ^ n minus one times itself + + + align:start position:0% +a n + 1 / 10 ^ n minus one times itself +but I'm I would just write it nicely out + + align:start position:0% +but I'm I would just write it nicely out + + + align:start position:0% +but I'm I would just write it nicely out +like this + + align:start position:0% + + + + align:start position:0% + +that this thing here remember the way + + align:start position:0% +that this thing here remember the way + + + align:start position:0% +that this thing here remember the way +the it go that this is equal to that + + align:start position:0% +the it go that this is equal to that + + + align:start position:0% +the it go that this is equal to that +which is bigger than one two so this + + align:start position:0% +which is bigger than one two so this + + + align:start position:0% +which is bigger than one two so this +here is bigger than two + + align:start position:0% +here is bigger than two + + + align:start position:0% +here is bigger than two +right Now 10 1 / 10 to the n you can + + align:start position:0% +right Now 10 1 / 10 to the n you can + + + align:start position:0% +right Now 10 1 / 10 to the n you can +think about that as a sequence right you + + align:start position:0% +think about that as a sequence right you + + + align:start position:0% +think about that as a sequence right you +can think about this as a sequence that + + align:start position:0% +can think about this as a sequence that + + + align:start position:0% +can think about this as a sequence that +sequence go to zero this here goes to a + + align:start position:0% +sequence go to zero this here goes to a + + + align:start position:0% +sequence go to zero this here goes to a +the sum of these two sequences by the + + align:start position:0% +the sum of these two sequences by the + + + align:start position:0% +the sum of these two sequences by the +algebraic rules go to the sum of the + + align:start position:0% +algebraic rules go to the sum of the + + + align:start position:0% +algebraic rules go to the sum of the +limits so this is a plus zero so that's + + align:start position:0% +limits so this is a plus zero so that's + + + align:start position:0% +limits so this is a plus zero so that's +a so this thing here goes to a and and + + align:start position:0% +a so this thing here goes to a and and + + + align:start position:0% +a so this thing here goes to a and and +this is the same so this goes to a so + + align:start position:0% +this is the same so this goes to a so + + + align:start position:0% +this is the same so this goes to a so +you see that the limit here then goes to + + align:start position:0% +you see that the limit here then goes to + + + align:start position:0% +you see that the limit here then goes to +by the product rule for the limits. The + + align:start position:0% +by the product rule for the limits. The + + + align:start position:0% +by the product rule for the limits. The +limit here is so you get that a squared + + align:start position:0% +limit here is so you get that a squared + + + align:start position:0% +limit here is so you get that a squared +here and since it holds for each element + + align:start position:0% +here and since it holds for each element + + + align:start position:0% +here and since it holds for each element +then it also holds for the limit right + + align:start position:0% +then it also holds for the limit right + + + align:start position:0% +then it also holds for the limit right +except you had to be a little bit + + align:start position:0% +except you had to be a little bit + + + align:start position:0% +except you had to be a little bit +careful it's may not be strict + + align:start position:0% +careful it's may not be strict + + + align:start position:0% +careful it's may not be strict +inequality but just big or equal to and + + align:start position:0% +inequality but just big or equal to and + + + align:start position:0% +inequality but just big or equal to and +of course in fact it is by equal to + + align:start position:0% +of course in fact it is by equal to + + + align:start position:0% +of course in fact it is by equal to +because now you have established the + + align:start position:0% +because now you have established the + + + align:start position:0% +because now you have established the +other inequality that a^2 was bigger + + align:start position:0% +other inequality that a^2 was bigger + + + align:start position:0% +other inequality that a^2 was bigger +equal to 2. We had already proven that + + align:start position:0% +equal to 2. We had already proven that + + + align:start position:0% +equal to 2. We had already proven that +a^2 was less or equal to two. So you + + align:start position:0% +a^2 was less or equal to two. So you + + + align:start position:0% +a^2 was less or equal to two. So you +conclude that a^2 is equal to two. + + align:start position:0% +conclude that a^2 is equal to two. + + + align:start position:0% +conclude that a^2 is equal to two. +If you kind of just think about it, this + + align:start position:0% +If you kind of just think about it, this + + + align:start position:0% +If you kind of just think about it, this +is really how it sounds maybe a little + + align:start position:0% +is really how it sounds maybe a little + + + align:start position:0% +is really how it sounds maybe a little +bit convoluted, but it's really kind of + + align:start position:0% +bit convoluted, but it's really kind of + + + align:start position:0% +bit convoluted, but it's really kind of +writing down precisely what you think + + align:start position:0% +writing down precisely what you think + + + align:start position:0% +writing down precisely what you think +about when you're singing about a square + + align:start position:0% +about when you're singing about a square + + + align:start position:0% +about when you're singing about a square +root of two because you think about the + + align:start position:0% +root of two because you think about the + + + align:start position:0% +root of two because you think about the +number of digits. And so if you take, + + align:start position:0% +number of digits. And so if you take, + + + align:start position:0% +number of digits. And so if you take, +you know, including the first the one in + + align:start position:0% +you know, including the first the one in + + + align:start position:0% +you know, including the first the one in +1.4 four B including that one. If you + + align:start position:0% +1.4 four B including that one. If you + + + align:start position:0% +1.4 four B including that one. If you +think about the number of digits + + align:start position:0% +think about the number of digits + + + align:start position:0% +think about the number of digits +like the A N then the A end is really + + align:start position:0% +like the A N then the A end is really + + + align:start position:0% +like the A N then the A end is really +defined if you were to make it precise + + align:start position:0% +defined if you were to make it precise + + + align:start position:0% +defined if you were to make it precise +you would define it in terms of this + + align:start position:0% +you would define it in terms of this + + + align:start position:0% +you would define it in terms of this +other sequence BN. Okay. + + align:start position:0% + + + + align:start position:0% + +Okay. So now the next thing is so this + + align:start position:0% +Okay. So now the next thing is so this + + + align:start position:0% +Okay. So now the next thing is so this +was just like + + align:start position:0% +was just like + + + align:start position:0% +was just like +a little illustration of how the mono + + align:start position:0% +a little illustration of how the mono + + + align:start position:0% +a little illustration of how the mono +convergence theorem worked. + + align:start position:0% +convergence theorem worked. + + + align:start position:0% +convergence theorem worked. +and and and and then and we this will + + align:start position:0% +and and and and then and we this will + + + align:start position:0% +and and and and then and we this will +you know play an important role next + + align:start position:0% +you know play an important role next + + + align:start position:0% +you know play an important role next +time we Yeah. + + align:start position:0% +time we Yeah. + + + align:start position:0% +time we Yeah. +>> So uh the reason why at the top we have + + align:start position:0% +>> So uh the reason why at the top we have + + + align:start position:0% +>> So uh the reason why at the top we have +like strictly greater than two and then + + align:start position:0% +like strictly greater than two and then + + + align:start position:0% +like strictly greater than two and then +at the bottom we have greater or equal + + align:start position:0% +at the bottom we have greater or equal + + + align:start position:0% +at the bottom we have greater or equal +to because the a and the a limits + + align:start position:0% +to because the a and the a limits + + + align:start position:0% +to because the a and the a limits +whereas on the top we're considering + + align:start position:0% +whereas on the top we're considering + + + align:start position:0% +whereas on the top we're considering +each element. + + align:start position:0% +each element. + + + align:start position:0% +each element. +>> So so this um the a + + align:start position:0% +>> So so this um the a + + + align:start position:0% +>> So so this um the a +this you were talking about this here + + align:start position:0% +this you were talking about this here + + + align:start position:0% +this you were talking about this here +right? + + align:start position:0% +right? + + + align:start position:0% +right? +>> Yeah. + + align:start position:0% +>> Yeah. + + + align:start position:0% +>> Yeah. +>> Yeah. So the a n converts to a right + + align:start position:0% +>> Yeah. So the a n converts to a right + + + align:start position:0% +>> Yeah. So the a n converts to a right +this here you I think about this here. + + align:start position:0% +this here you I think about this here. + + + align:start position:0% +this here you I think about this here. +So think about a sequence plus another + + align:start position:0% +So think about a sequence plus another + + + align:start position:0% +So think about a sequence plus another +sequence, right? This sequence here + + align:start position:0% +sequence, right? This sequence here + + + align:start position:0% +sequence, right? This sequence here +converts to zero, right? So the sum of + + align:start position:0% +converts to zero, right? So the sum of + + + align:start position:0% +converts to zero, right? So the sum of +these two sequences converts to zero. + + align:start position:0% +these two sequences converts to zero. + + + align:start position:0% +these two sequences converts to zero. +And likewise for this and then I'm + + align:start position:0% +And likewise for this and then I'm + + + align:start position:0% +And likewise for this and then I'm +thinking about it as a product of this + + align:start position:0% +thinking about it as a product of this + + + align:start position:0% +thinking about it as a product of this +sequence with that sequence. And so but + + align:start position:0% +sequence with that sequence. And so but + + + align:start position:0% +sequence with that sequence. And so but +but it's like each element is in that in + + align:start position:0% +but it's like each element is in that in + + + align:start position:0% +but it's like each element is in that in +this in the product sequence is strictly + + align:start position:0% +this in the product sequence is strictly + + + align:start position:0% +this in the product sequence is strictly +bigger than two. But it doesn't + + align:start position:0% +bigger than two. But it doesn't + + + align:start position:0% +bigger than two. But it doesn't +necessarily mean that the limit is + + align:start position:0% +necessarily mean that the limit is + + + align:start position:0% +necessarily mean that the limit is +strictly but the limit has to be bigger + + align:start position:0% +strictly but the limit has to be bigger + + + align:start position:0% +strictly but the limit has to be bigger +than two, right? Because they could kind + + align:start position:0% +than two, right? Because they could kind + + + align:start position:0% +than two, right? Because they could kind +of approach two and that's exactly what + + align:start position:0% +of approach two and that's exactly what + + + align:start position:0% +of approach two and that's exactly what +happened of course. Yeah. + + align:start position:0% +happened of course. Yeah. + + + align:start position:0% +happened of course. Yeah. +Uh okay. So and and so I also just want + + align:start position:0% +Uh okay. So and and so I also just want + + + align:start position:0% +Uh okay. So and and so I also just want +to say that this with lee soup and le + + align:start position:0% +to say that this with lee soup and le + + + align:start position:0% +to say that this with lee soup and le +mint well we didn't actually define it + + align:start position:0% +mint well we didn't actually define it + + + align:start position:0% +mint well we didn't actually define it +but I defined you know and this is it is + + align:start position:0% +but I defined you know and this is it is + + + align:start position:0% +but I defined you know and this is it is +how you defining but but we haven't + + align:start position:0% +how you defining but but we haven't + + + align:start position:0% +how you defining but but we haven't +talked about that concept yet but this I + + align:start position:0% +talked about that concept yet but this I + + + align:start position:0% +talked about that concept yet but this I +talked about with that if you take a + + align:start position:0% +talked about with that if you take a + + + align:start position:0% +talked about with that if you take a +boundary sequence then you could form + + align:start position:0% +boundary sequence then you could form + + + align:start position:0% +boundary sequence then you could form +two mono sequences this this will play a + + align:start position:0% +two mono sequences this this will play a + + + align:start position:0% +two mono sequences this this will play a +really important role for several things + + align:start position:0% +really important role for several things + + + align:start position:0% +really important role for several things +this is how one define the soup and the + + align:start position:0% +this is how one define the soup and the + + + align:start position:0% +this is how one define the soup and the +min haven't talked about those yet. It's + + align:start position:0% +min haven't talked about those yet. It's + + + align:start position:0% +min haven't talked about those yet. It's +also going to be used + + align:start position:0% +also going to be used + + + align:start position:0% +also going to be used +to prove an important theorem really + + align:start position:0% +to prove an important theorem really + + + align:start position:0% +to prove an important theorem really +important theorem and that's what and + + align:start position:0% +important theorem and that's what and + + + align:start position:0% +important theorem and that's what and +that I will talk about that theorem next + + align:start position:0% +that I will talk about that theorem next + + + align:start position:0% +that I will talk about that theorem next +but we won't prove it before next time. + + align:start position:0% +but we won't prove it before next time. + + + align:start position:0% +but we won't prove it before next time. +So what is what is that stuff going to + + align:start position:0% +So what is what is that stuff going to + + + align:start position:0% +So what is what is that stuff going to +be used + + align:start position:0% +be used + + + align:start position:0% +be used +and and and how does the monotone in + + align:start position:0% +and and and how does the monotone in + + + align:start position:0% +and and and how does the monotone in +what is another application and in fact + + align:start position:0% +what is another application and in fact + + + align:start position:0% +what is another application and in fact +there'll be several other applications + + align:start position:0% +there'll be several other applications + + + align:start position:0% +there'll be several other applications +of the monotone convergence theorem + + align:start position:0% +of the monotone convergence theorem + + + align:start position:0% +of the monotone convergence theorem +but so here is um here's a really + + align:start position:0% +but so here is um here's a really + + + align:start position:0% +but so here is um here's a really +important concept + + align:start position:0% +important concept + + + align:start position:0% +important concept +and so sometimes it's hard to you know + + align:start position:0% +and so sometimes it's hard to you know + + + align:start position:0% +and so sometimes it's hard to you know +in in if it was a monotom sequence then + + align:start position:0% +in in if it was a monotom sequence then + + + align:start position:0% +in in if it was a monotom sequence then +you could kind of write down explicitly + + align:start position:0% +you could kind of write down explicitly + + + align:start position:0% +you could kind of write down explicitly +what the limits were, right? And in all + + align:start position:0% +what the limits were, right? And in all + + + align:start position:0% +what the limits were, right? And in all +of the examples we saw so far, it was + + align:start position:0% +of the examples we saw so far, it was + + + align:start position:0% +of the examples we saw so far, it was +easy to write down the limits, but in + + align:start position:0% +easy to write down the limits, but in + + + align:start position:0% +easy to write down the limits, but in +general, + + align:start position:0% +general, + + + align:start position:0% +general, +you might not be able to write down the + + align:start position:0% +you might not be able to write down the + + + align:start position:0% +you might not be able to write down the +limits, but you want to prove that the + + align:start position:0% +limits, but you want to prove that the + + + align:start position:0% +limits, but you want to prove that the +limit exists. And so, this is the + + align:start position:0% +limit exists. And so, this is the + + + align:start position:0% +limit exists. And so, this is the +following notion that is then becomes + + align:start position:0% +following notion that is then becomes + + + align:start position:0% +following notion that is then becomes +really handy, and that's a notion of a + + align:start position:0% +really handy, and that's a notion of a + + + align:start position:0% +really handy, and that's a notion of a +cushy sequence. + + align:start position:0% + + + + align:start position:0% + +So what is a cushy sequence? So a cushi + + align:start position:0% +So what is a cushy sequence? So a cushi + + + align:start position:0% +So what is a cushy sequence? So a cushi +sequence. So it's a sequence a sequence + + align:start position:0% + + + + align:start position:0% + +with the property + + align:start position:0% + + + + align:start position:0% + +that + + align:start position:0% +that + + + align:start position:0% +that +for all + + align:start position:0% + + + + align:start position:0% + +epsilon greater than zero there exist + + align:start position:0% +epsilon greater than zero there exist + + + align:start position:0% +epsilon greater than zero there exist +n + + align:start position:0% +n + + + align:start position:0% +n +there exist a natural number n + + align:start position:0% + + + + align:start position:0% + +such that + + align:start position:0% +such that + + + align:start position:0% +such that +if n and m are bigger than this natural + + align:start position:0% +if n and m are bigger than this natural + + + align:start position:0% +if n and m are bigger than this natural +number + + align:start position:0% +number + + + align:start position:0% +number +then the + + align:start position:0% +then the + + + align:start position:0% +then the +two elements a n and and a m are less + + align:start position:0% +two elements a n and and a m are less + + + align:start position:0% +two elements a n and and a m are less +than epsilon apart. + + align:start position:0% +than epsilon apart. + + + align:start position:0% +than epsilon apart. +So like the so this is a different + + align:start position:0% +So like the so this is a different + + + align:start position:0% +So like the so this is a different +notion than convergence. Convergence + + align:start position:0% +notion than convergence. Convergence + + + align:start position:0% +notion than convergence. Convergence +say that if you that a sequence is + + align:start position:0% +say that if you that a sequence is + + + align:start position:0% +say that if you that a sequence is +convergent if everything kind of far out + + align:start position:0% +convergent if everything kind of far out + + + align:start position:0% +convergent if everything kind of far out +accumulates around the limit. Right? + + align:start position:0% +accumulates around the limit. Right? + + + align:start position:0% +accumulates around the limit. Right? +This here say that that and + + align:start position:0% +This here say that that and + + + align:start position:0% +This here say that that and +and of course it will. So this has say + + align:start position:0% +and of course it will. So this has say + + + align:start position:0% +and of course it will. So this has say +that if you that a cushie sequence + + align:start position:0% +that if you that a cushie sequence + + + align:start position:0% +that if you that a cushie sequence +that's a sequence so that if you are far + + align:start position:0% +that's a sequence so that if you are far + + + align:start position:0% +that's a sequence so that if you are far +out then syncs a bunch together + + align:start position:0% +out then syncs a bunch together + + + align:start position:0% +out then syncs a bunch together +basically right now of course we will + + align:start position:0% +basically right now of course we will + + + align:start position:0% +basically right now of course we will +prove and so we prove for the on r + + align:start position:0% + + + + align:start position:0% + +we will prove that the cy sequence + + align:start position:0% + + + + align:start position:0% + +so we prove + + align:start position:0% +so we prove + + + align:start position:0% +so we prove +that + + align:start position:0% +that + + + align:start position:0% +that +so we prove the following + + align:start position:0% +so we prove the following + + + align:start position:0% +so we prove the following +um + + align:start position:0% +um + + + align:start position:0% +um +put for + + align:start position:0% +put for + + + align:start position:0% +put for +that that's on R but everything is on R + + align:start position:0% +that that's on R but everything is on R + + + align:start position:0% +that that's on R but everything is on R +at the moment uh that any that a + + align:start position:0% +at the moment uh that any that a + + + align:start position:0% +at the moment uh that any that a +sequence + + align:start position:0% + + + + align:start position:0% + +is a cushy sequence + + align:start position:0% + + + + align:start position:0% + +sequence + + align:start position:0% +sequence + + + align:start position:0% +sequence +if and only if + + align:start position:0% + + + + align:start position:0% + +only if it is + + align:start position:0% +only if it is + + + align:start position:0% +only if it is +convergent. + + align:start position:0% + + + + align:start position:0% + +Okay, I won't prove this now but but + + align:start position:0% +Okay, I won't prove this now but but + + + align:start position:0% +Okay, I won't prove this now but but +I'll prove this next time + + align:start position:0% +I'll prove this next time + + + align:start position:0% +I'll prove this next time +and and again the proof of this involve + + align:start position:0% +and and again the proof of this involve + + + align:start position:0% +and and again the proof of this involve +this stuff with we define these two + + align:start position:0% +this stuff with we define these two + + + align:start position:0% +this stuff with we define these two +sequences from a bounded sequence. So it + + align:start position:0% +sequences from a bounded sequence. So it + + + align:start position:0% +sequences from a bounded sequence. So it +it would be useful there. Um + + align:start position:0% +it would be useful there. Um + + + align:start position:0% +it would be useful there. Um +uh now let me give you some examples. Um + + align:start position:0% +uh now let me give you some examples. Um + + + align:start position:0% +uh now let me give you some examples. Um +so one uh one uh + + align:start position:0% +so one uh one uh + + + align:start position:0% +so one uh one uh +one um example and the thing is that + + align:start position:0% +one um example and the thing is that + + + align:start position:0% +one um example and the thing is that +that and we'll get to that later but as + + align:start position:0% +that and we'll get to that later but as + + + align:start position:0% +that and we'll get to that later but as +at the moment we talk everything is in R + + align:start position:0% +at the moment we talk everything is in R + + + align:start position:0% +at the moment we talk everything is in R +and then we will later generalize this + + align:start position:0% +and then we will later generalize this + + + align:start position:0% +and then we will later generalize this +right and so to generalize this a lot of + + align:start position:0% +right and so to generalize this a lot of + + + align:start position:0% +right and so to generalize this a lot of +these concepts work much more general + + align:start position:0% +these concepts work much more general + + + align:start position:0% +these concepts work much more general +and and that's extremely useful and Um + + align:start position:0% +and and that's extremely useful and Um + + + align:start position:0% +and and that's extremely useful and Um +and it can be used to + + align:start position:0% +and it can be used to + + + align:start position:0% +and it can be used to +find solutions to differential equations + + align:start position:0% +find solutions to differential equations + + + align:start position:0% +find solutions to differential equations +but uh and but then you have to abstract + + align:start position:0% +but uh and but then you have to abstract + + + align:start position:0% +but uh and but then you have to abstract +these concepts. So uh to where sequences + + align:start position:0% +these concepts. So uh to where sequences + + + align:start position:0% +these concepts. So uh to where sequences +are not anymore real numbers but they + + align:start position:0% +are not anymore real numbers but they + + + align:start position:0% +are not anymore real numbers but they +are of some other space and then you + + align:start position:0% +are of some other space and then you + + + align:start position:0% +are of some other space and then you +have to talk about convergence etc. + + align:start position:0% +have to talk about convergence etc. + + + align:start position:0% +have to talk about convergence etc. +And so you can use this to to define um + + align:start position:0% +And so you can use this to to define um + + + align:start position:0% +And so you can use this to to define um +solutions to def to show that various + + align:start position:0% +solutions to def to show that various + + + align:start position:0% +solutions to def to show that various +differential equations + + align:start position:0% +differential equations + + + align:start position:0% +differential equations +uh have solutions. Okay. And so that + + align:start position:0% +uh have solutions. Okay. And so that + + + align:start position:0% +uh have solutions. Okay. And so that +often goes over using what's called the + + align:start position:0% +often goes over using what's called the + + + align:start position:0% +often goes over using what's called the +contracting mapping the + + align:start position:0% + + + + align:start position:0% + +mapping. + + align:start position:0% + + + + align:start position:0% + +and and the contracting mappings + + align:start position:0% +and and the contracting mappings + + + align:start position:0% +and and the contracting mappings +theorem, you know, have all kind of + + align:start position:0% +theorem, you know, have all kind of + + + align:start position:0% +theorem, you know, have all kind of +forms and uh the but they're all, you + + align:start position:0% +forms and uh the but they're all, you + + + align:start position:0% +forms and uh the but they're all, you +know, it's just a matter of what space + + align:start position:0% +know, it's just a matter of what space + + + align:start position:0% +know, it's just a matter of what space +you're looking at and and so on. Uh but + + align:start position:0% +you're looking at and and so on. Uh but + + + align:start position:0% +you're looking at and and so on. Uh but +so we're looking at R here in this case. + + align:start position:0% +so we're looking at R here in this case. + + + align:start position:0% +so we're looking at R here in this case. +And so the contracting mapping theorem, + + align:start position:0% +And so the contracting mapping theorem, + + + align:start position:0% +And so the contracting mapping theorem, +that's a map is just a it's just a map + + align:start position:0% +that's a map is just a it's just a map + + + align:start position:0% +that's a map is just a it's just a map +here now from R to R. + + align:start position:0% +here now from R to R. + + + align:start position:0% +here now from R to R. +And that the map is contracting means + + align:start position:0% +And that the map is contracting means + + + align:start position:0% +And that the map is contracting means +that if you take two elements + + align:start position:0% +that if you take two elements + + + align:start position:0% +that if you take two elements +uh in + + align:start position:0% +uh in + + + align:start position:0% +uh in +uh so it means that sorry T is a + + align:start position:0% +uh so it means that sorry T is a + + + align:start position:0% +uh so it means that sorry T is a +contracting map + + align:start position:0% +contracting map + + + align:start position:0% +contracting map +is a contracting map + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +if they exist. + + align:start position:0% +if they exist. + + + align:start position:0% +if they exist. +[Applause] + + align:start position:0% + + + + align:start position:0% + +And this is really important. C is is + + align:start position:0% +And this is really important. C is is + + + align:start position:0% +And this is really important. C is is +positive. I mean that's not important. + + align:start position:0% +positive. I mean that's not important. + + + align:start position:0% +positive. I mean that's not important. +It sort of had to be positive. So that's + + align:start position:0% +It sort of had to be positive. So that's + + + align:start position:0% +It sort of had to be positive. So that's +but the the the important point is that + + align:start position:0% +but the the the important point is that + + + align:start position:0% +but the the the important point is that +C has to be strictly less than one. That + + align:start position:0% +C has to be strictly less than one. That + + + align:start position:0% +C has to be strictly less than one. That +that's a crucial point. + + align:start position:0% +that's a crucial point. + + + align:start position:0% +that's a crucial point. +Um and then it then it has a property + + align:start position:0% +Um and then it then it has a property + + + align:start position:0% +Um and then it then it has a property +that when you apply when you take X and + + align:start position:0% +that when you apply when you take X and + + + align:start position:0% +that when you apply when you take X and +Y in this in R and you're looking at the + + align:start position:0% +Y in this in R and you're looking at the + + + align:start position:0% +Y in this in R and you're looking at the +how close X and Y are together. So the + + align:start position:0% +how close X and Y are together. So the + + + align:start position:0% +how close X and Y are together. So the +how close that the image + + align:start position:0% +how close that the image + + + align:start position:0% +how close that the image +uh under t of x and y how close they are + + align:start position:0% +uh under t of x and y how close they are + + + align:start position:0% +uh under t of x and y how close they are +together + + align:start position:0% +together + + + align:start position:0% +together +then those have to be some factor and + + align:start position:0% +then those have to be some factor and + + + align:start position:0% +then those have to be some factor and +this is the factor the c is the factor + + align:start position:0% + + + + align:start position:0% + +and that has so they have to come + + align:start position:0% +and that has so they have to come + + + align:start position:0% +and that has so they have to come +closer. This is why c have to be + + align:start position:0% +closer. This is why c have to be + + + align:start position:0% +closer. This is why c have to be +strictly less than one because they have + + align:start position:0% +strictly less than one because they have + + + align:start position:0% +strictly less than one because they have +to come closer. If they come closer by a + + align:start position:0% +to come closer. If they come closer by a + + + align:start position:0% +to come closer. If they come closer by a +factor than the original one was then + + align:start position:0% +factor than the original one was then + + + align:start position:0% +factor than the original one was then +then so the contracting mapping theorem + + align:start position:0% +then so the contracting mapping theorem + + + align:start position:0% +then so the contracting mapping theorem +say so this is a contracting map sorry + + align:start position:0% +say so this is a contracting map sorry + + + align:start position:0% +say so this is a contracting map sorry +so a contracting map is a map from R to + + align:start position:0% +so a contracting map is a map from R to + + + align:start position:0% +so a contracting map is a map from R to +R so that there exists some constant + + align:start position:0% +R so that there exists some constant + + + align:start position:0% +R so that there exists some constant +strictly less than one so that for all X + + align:start position:0% +strictly less than one so that for all X + + + align:start position:0% +strictly less than one so that for all X +and Y you have that the difference + + align:start position:0% +and Y you have that the difference + + + align:start position:0% +and Y you have that the difference +between the images is this factor that + + align:start position:0% +between the images is this factor that + + + align:start position:0% +between the images is this factor that +is strictly less than on with what they + + align:start position:0% +is strictly less than on with what they + + + align:start position:0% +is strictly less than on with what they +were originally + + align:start position:0% +were originally + + + align:start position:0% +were originally +and so now you get the contracting + + align:start position:0% +and so now you get the contracting + + + align:start position:0% +and so now you get the contracting +mapping theorem and we'll talk about the + + align:start position:0% +mapping theorem and we'll talk about the + + + align:start position:0% +mapping theorem and we'll talk about the +proof next time and and again this you + + align:start position:0% +proof next time and and again this you + + + align:start position:0% +proof next time and and again this you +know + + align:start position:0% +know + + + align:start position:0% +know +you know once you have know the more + + align:start position:0% +you know once you have know the more + + + align:start position:0% +you know once you have know the more +abstract concepts then it's quite easy I + + align:start position:0% +abstract concepts then it's quite easy I + + + align:start position:0% +abstract concepts then it's quite easy I +mean the proof is going to be the same + + align:start position:0% +mean the proof is going to be the same + + + align:start position:0% +mean the proof is going to be the same +etc etc and will give you existence of + + align:start position:0% +etc etc and will give you existence of + + + align:start position:0% +etc etc and will give you existence of +solutions to a lot of differential + + align:start position:0% +solutions to a lot of differential + + + align:start position:0% +solutions to a lot of differential +equation so this is the contracting + + align:start position:0% +equation so this is the contracting + + + align:start position:0% +equation so this is the contracting +mapping term + + align:start position:0% + + + + align:start position:0% + +So it say the following that if + + align:start position:0% +So it say the following that if + + + align:start position:0% +So it say the following that if +uh t from r to r + + align:start position:0% + + + + align:start position:0% + +is a contracting + + align:start position:0% + + + + align:start position:0% + +Then + + align:start position:0% +Then + + + align:start position:0% +Then +then C + + align:start position:0% +then C + + + align:start position:0% +then C +has a fixed point. + + align:start position:0% + + + + align:start position:0% + +It has a fixed point. + + align:start position:0% + + + + align:start position:0% + +And this means that t of x is equal to + + align:start position:0% +And this means that t of x is equal to + + + align:start position:0% +And this means that t of x is equal to +x. And when you apply this theorem, + + align:start position:0% +x. And when you apply this theorem, + + + align:start position:0% +x. And when you apply this theorem, +the contract. So this is the contracting + + align:start position:0% +the contract. So this is the contracting + + + align:start position:0% +the contract. So this is the contracting +mapping. And again, it's crucial that + + align:start position:0% +mapping. And again, it's crucial that + + + align:start position:0% +mapping. And again, it's crucial that +this C is less than one. That's what + + align:start position:0% +this C is less than one. That's what + + + align:start position:0% +this C is less than one. That's what +makes everything go. If it's if it was + + align:start position:0% +makes everything go. If it's if it was + + + align:start position:0% +makes everything go. If it's if it was +equal to one, you wouldn't get anything. + + align:start position:0% +equal to one, you wouldn't get anything. + + + align:start position:0% +equal to one, you wouldn't get anything. +Okay? It has to be strictly less than + + align:start position:0% +Okay? It has to be strictly less than + + + align:start position:0% +Okay? It has to be strictly less than +one. + + align:start position:0% +one. + + + align:start position:0% +one. +And this thing here, if you set it up + + align:start position:0% +And this thing here, if you set it up + + + align:start position:0% +And this thing here, if you set it up +more generally, you know, if the spaces + + align:start position:0% +more generally, you know, if the spaces + + + align:start position:0% +more generally, you know, if the spaces +are more general than just the real + + align:start position:0% +are more general than just the real + + + align:start position:0% +are more general than just the real +numbers, then then this here will be + + align:start position:0% +numbers, then then this here will be + + + align:start position:0% +numbers, then then this here will be +that you have a solution. It it could be + + align:start position:0% +that you have a solution. It it could be + + + align:start position:0% +that you have a solution. It it could be +it can be applied to many other things, + + align:start position:0% +it can be applied to many other things, + + + align:start position:0% +it can be applied to many other things, +but it could be that you have a solution + + align:start position:0% +but it could be that you have a solution + + + align:start position:0% +but it could be that you have a solution +to a differential equation. This + + align:start position:0% +to a differential equation. This + + + align:start position:0% +to a differential equation. This +statement here, you know, is like a + + align:start position:0% +statement here, you know, is like a + + + align:start position:0% +statement here, you know, is like a +standard application to get solutions to + + align:start position:0% +standard application to get solutions to + + + align:start position:0% +standard application to get solutions to +differential equations and you know, you + + align:start position:0% +differential equations and you know, you + + + align:start position:0% +differential equations and you know, you +can do use for all kind of stuff. Okay. + + align:start position:0% +can do use for all kind of stuff. Okay. + + + align:start position:0% +can do use for all kind of stuff. Okay. +And so uh so we'll talk about that next + + align:start position:0% +And so uh so we'll talk about that next + + + align:start position:0% +And so uh so we'll talk about that next +time. Uh and not maybe not the the the I + + align:start position:0% +time. Uh and not maybe not the the the I + + + align:start position:0% +time. Uh and not maybe not the the the I +talk about the contracting mapping the + + align:start position:0% +talk about the contracting mapping the + + + align:start position:0% +talk about the contracting mapping the +won't talk quite yet about the + + align:start position:0% +won't talk quite yet about the + + + align:start position:0% +won't talk quite yet about the +applications. + + align:start position:0% +applications. + + + align:start position:0% +applications. +Any questions? + + align:start position:0% +Any questions? + + + align:start position:0% +Any questions? +Okay. Great. \ No newline at end of file diff --git a/Fce9xf_kjyc.txt b/Fce9xf_kjyc.txt new file mode 100644 index 0000000000000000000000000000000000000000..ac51bc17c93437c00d731e537e0bb7e00f9d90f9 --- /dev/null +++ b/Fce9xf_kjyc.txt @@ -0,0 +1,17979 @@ +align:start position:0% + +foreign + + align:start position:0% + + + + align:start position:0% + +on the first part of our new kind of + + align:start position:0% +on the first part of our new kind of + + + align:start position:0% +on the first part of our new kind of +material new set of material on quantum + + align:start position:0% +material new set of material on quantum + + + align:start position:0% +material new set of material on quantum +theory so we talked a bit about uh the + + align:start position:0% +theory so we talked a bit about uh the + + + align:start position:0% +theory so we talked a bit about uh the +road toward relativity uh in in this + + align:start position:0% +road toward relativity uh in in this + + + align:start position:0% +road toward relativity uh in in this +first few + + align:start position:0% +first few + + + align:start position:0% +first few +uh class sessions we're going to Pivot + + align:start position:0% +uh class sessions we're going to Pivot + + + align:start position:0% +uh class sessions we're going to Pivot +now and talk about this other sort of + + align:start position:0% +now and talk about this other sort of + + + align:start position:0% +now and talk about this other sort of +amazing uh edifice of what becomes known + + align:start position:0% +amazing uh edifice of what becomes known + + + align:start position:0% +amazing uh edifice of what becomes known +as modern physics quantum theory as as + + align:start position:0% +as modern physics quantum theory as as + + + align:start position:0% +as modern physics quantum theory as as +that was getting pieced together over + + align:start position:0% +that was getting pieced together over + + + align:start position:0% +that was getting pieced together over +the first kind of quarter Century or so + + align:start position:0% +the first kind of quarter Century or so + + + align:start position:0% +the first kind of quarter Century or so +of the 20th century uh so for this + + align:start position:0% +of the 20th century uh so for this + + + align:start position:0% +of the 20th century uh so for this +material + + align:start position:0% +material + + + align:start position:0% +material +which has been this class session and + + align:start position:0% +which has been this class session and + + + align:start position:0% +which has been this class session and +the next one talking about what came to + + align:start position:0% +the next one talking about what came to + + + align:start position:0% +the next one talking about what came to +be known as old quantum theory of course + + align:start position:0% +be known as old quantum theory of course + + + align:start position:0% +be known as old quantum theory of course +it only became known as old quantum + + align:start position:0% +it only became known as old quantum + + + align:start position:0% +it only became known as old quantum +theory once there was a new quantum + + align:start position:0% +theory once there was a new quantum + + + align:start position:0% +theory once there was a new quantum +theory that seemed to replace it and so + + align:start position:0% +theory that seemed to replace it and so + + + align:start position:0% +theory that seemed to replace it and so +physicists themselves introduced the + + align:start position:0% +physicists themselves introduced the + + + align:start position:0% +physicists themselves introduced the +term old quantum theory kind of within + + align:start position:0% +term old quantum theory kind of within + + + align:start position:0% +term old quantum theory kind of within +the time zone that we'll be talking + + align:start position:0% +the time zone that we'll be talking + + + align:start position:0% +the time zone that we'll be talking +about + + align:start position:0% +about + + + align:start position:0% +about +so in their own Reckoning + + align:start position:0% +so in their own Reckoning + + + align:start position:0% +so in their own Reckoning +by the mid to late 1920s physicists + + align:start position:0% +by the mid to late 1920s physicists + + + align:start position:0% +by the mid to late 1920s physicists +began to refer by the term of old + + align:start position:0% +began to refer by the term of old + + + align:start position:0% +began to refer by the term of old +quantum theory to this collection of + + align:start position:0% +quantum theory to this collection of + + + align:start position:0% +quantum theory to this collection of +work that it unfolded really between + + align:start position:0% +work that it unfolded really between + + + align:start position:0% +work that it unfolded really between +around 1900 and 1924 that looked like + + align:start position:0% +around 1900 and 1924 that looked like + + + align:start position:0% +around 1900 and 1924 that looked like +the old period once the new stuff had + + align:start position:0% +the old period once the new stuff had + + + align:start position:0% +the old period once the new stuff had +begun to coalesce in 1925 and 26 and so + + align:start position:0% +begun to coalesce in 1925 and 26 and so + + + align:start position:0% +begun to coalesce in 1925 and 26 and so +on now here I have an asterisk hope you + + align:start position:0% +on now here I have an asterisk hope you + + + align:start position:0% +on now here I have an asterisk hope you +can see that these dates are approximate + + align:start position:0% +can see that these dates are approximate + + + align:start position:0% +can see that these dates are approximate +one of the things we'll be really + + align:start position:0% +one of the things we'll be really + + + align:start position:0% +one of the things we'll be really +sitting with throughout these first few + + align:start position:0% +sitting with throughout these first few + + + align:start position:0% +sitting with throughout these first few +uh discussions about about quantum + + align:start position:0% +uh discussions about about quantum + + + align:start position:0% +uh discussions about about quantum +theory is just how much sort of in play + + align:start position:0% +theory is just how much sort of in play + + + align:start position:0% +theory is just how much sort of in play +these developments remained well after + + align:start position:0% +these developments remained well after + + + align:start position:0% +these developments remained well after +the kind of um nominal date in which + + align:start position:0% +the kind of um nominal date in which + + + align:start position:0% +the kind of um nominal date in which +they were put forward much like we saw + + align:start position:0% +they were put forward much like we saw + + + align:start position:0% +they were put forward much like we saw +with relativity + + align:start position:0% +with relativity + + + align:start position:0% +with relativity +it wasn't that Einstein published his + + align:start position:0% +it wasn't that Einstein published his + + + align:start position:0% +it wasn't that Einstein published his +paper on the electrodynamics of moving + + align:start position:0% +paper on the electrodynamics of moving + + + align:start position:0% +paper on the electrodynamics of moving +bodies in 1905 and then sort of the next + + align:start position:0% +bodies in 1905 and then sort of the next + + + align:start position:0% +bodies in 1905 and then sort of the next +day everyone woke up and was a devoted + + align:start position:0% +day everyone woke up and was a devoted + + + align:start position:0% +day everyone woke up and was a devoted +einsteinian or um or a convinced + + align:start position:0% +einsteinian or um or a convinced + + + align:start position:0% +einsteinian or um or a convinced +relativist likewise here with these + + align:start position:0% +relativist likewise here with these + + + align:start position:0% +relativist likewise here with these +developments on on uh the early steps + + align:start position:0% +developments on on uh the early steps + + + align:start position:0% +developments on on uh the early steps +toward quantum mechanics that these + + align:start position:0% +toward quantum mechanics that these + + + align:start position:0% +toward quantum mechanics that these +these ideas themselves were unfolding + + align:start position:0% +these ideas themselves were unfolding + + + align:start position:0% +these ideas themselves were unfolding +over time they were subject to sometimes + + align:start position:0% +over time they were subject to sometimes + + + align:start position:0% +over time they were subject to sometimes +quite wide-ranging debate and and + + align:start position:0% +quite wide-ranging debate and and + + + align:start position:0% +quite wide-ranging debate and and +varying interpretation so these dates + + align:start position:0% +varying interpretation so these dates + + + align:start position:0% +varying interpretation so these dates +are really meant to be approximate to + + align:start position:0% +are really meant to be approximate to + + + align:start position:0% +are really meant to be approximate to +help us understand the kind of General + + align:start position:0% +help us understand the kind of General + + + align:start position:0% +help us understand the kind of General +flow of this body of work between + + align:start position:0% +flow of this body of work between + + + align:start position:0% +flow of this body of work between +roughly 1900 + + align:start position:0% +roughly 1900 + + + align:start position:0% +roughly 1900 +in 1924. so I I find it helpful to + + align:start position:0% +in 1924. so I I find it helpful to + + + align:start position:0% +in 1924. so I I find it helpful to +divide up that first period of roughly + + align:start position:0% +divide up that first period of roughly + + + align:start position:0% +divide up that first period of roughly +25 years or so into a set of + + align:start position:0% +25 years or so into a set of + + + align:start position:0% +25 years or so into a set of +developments in which physicists began + + align:start position:0% +developments in which physicists began + + + align:start position:0% +developments in which physicists began +rethinking the nature of light that's + + align:start position:0% +rethinking the nature of light that's + + + align:start position:0% +rethinking the nature of light that's +what we'll talk about today today's + + align:start position:0% +what we'll talk about today today's + + + align:start position:0% +what we'll talk about today today's +rethinking light and they're really kind + + align:start position:0% +rethinking light and they're really kind + + + align:start position:0% +rethinking light and they're really kind +of interwoven with those developments as + + align:start position:0% +of interwoven with those developments as + + + align:start position:0% +of interwoven with those developments as +we'll see in our next class session + + align:start position:0% +we'll see in our next class session + + + align:start position:0% +we'll see in our next class session +we're a series of uh kind of equally + + align:start position:0% +we're a series of uh kind of equally + + + align:start position:0% +we're a series of uh kind of equally +surprising developments uh in which + + align:start position:0% +surprising developments uh in which + + + align:start position:0% +surprising developments uh in which +physicists were rethinking the nature of + + align:start position:0% +physicists were rethinking the nature of + + + align:start position:0% +physicists were rethinking the nature of +matter + + align:start position:0% +matter + + + align:start position:0% +matter +they didn't always make that division so + + align:start position:0% +they didn't always make that division so + + + align:start position:0% +they didn't always make that division so +clear at the time but again with a bit + + align:start position:0% +clear at the time but again with a bit + + + align:start position:0% +clear at the time but again with a bit +of hindsight once the newer work began + + align:start position:0% +of hindsight once the newer work began + + + align:start position:0% +of hindsight once the newer work began +to coalesce what we now call quantum + + align:start position:0% +to coalesce what we now call quantum + + + align:start position:0% +to coalesce what we now call quantum +mechanics this kind of division of the + + align:start position:0% +mechanics this kind of division of the + + + align:start position:0% +mechanics this kind of division of the +strands within old quantum theory made a + + align:start position:0% +strands within old quantum theory made a + + + align:start position:0% +strands within old quantum theory made a +bit more sense + + align:start position:0% +bit more sense + + + align:start position:0% +bit more sense +and again just a reminder for today it's + + align:start position:0% +and again just a reminder for today it's + + + align:start position:0% +and again just a reminder for today it's +thoroughly optional as always but for + + align:start position:0% +thoroughly optional as always but for + + + align:start position:0% +thoroughly optional as always but for +those who might be interested in having + + align:start position:0% +those who might be interested in having + + + align:start position:0% +those who might be interested in having +more time + + align:start position:0% +more time + + + align:start position:0% +more time +I did post some additional lecture notes + + align:start position:0% +I did post some additional lecture notes + + + align:start position:0% +I did post some additional lecture notes +on the canvas site they're going to go + + align:start position:0% +on the canvas site they're going to go + + + align:start position:0% +on the canvas site they're going to go +go into a little more detail about Parts + + align:start position:0% +go into a little more detail about Parts + + + align:start position:0% +go into a little more detail about Parts +one and three for today's material in + + align:start position:0% +one and three for today's material in + + + align:start position:0% +one and three for today's material in +particular both black body radiation and + + align:start position:0% +particular both black body radiation and + + + align:start position:0% +particular both black body radiation and +competence Gathering so if some ideas go + + align:start position:0% +competence Gathering so if some ideas go + + + align:start position:0% +competence Gathering so if some ideas go +by really quickly or you have no idea + + align:start position:0% +by really quickly or you have no idea + + + align:start position:0% +by really quickly or you have no idea +where that particular equation came from + + align:start position:0% +where that particular equation came from + + + align:start position:0% +where that particular equation came from +uh there is a bit more that you can + + align:start position:0% +uh there is a bit more that you can + + + align:start position:0% +uh there is a bit more that you can +delve into on the course site okay + + align:start position:0% +delve into on the course site okay + + + align:start position:0% +delve into on the course site okay +so before we even talk about who was + + align:start position:0% +so before we even talk about who was + + + align:start position:0% +so before we even talk about who was +rethinking light where and when it's + + align:start position:0% +rethinking light where and when it's + + + align:start position:0% +rethinking light where and when it's +really helpful it's very important to to + + align:start position:0% +really helpful it's very important to to + + + align:start position:0% +really helpful it's very important to to +step back and get remind yourself again + + align:start position:0% +step back and get remind yourself again + + + align:start position:0% +step back and get remind yourself again +of where this is happening uh and and + + align:start position:0% +of where this is happening uh and and + + + align:start position:0% +of where this is happening uh and and +why was happening at that time so a lot + + align:start position:0% +why was happening at that time so a lot + + + align:start position:0% +why was happening at that time so a lot +of the work that we're focusing on + + align:start position:0% +of the work that we're focusing on + + + align:start position:0% +of the work that we're focusing on +around on on today's uh class in + + align:start position:0% +around on on today's uh class in + + + align:start position:0% +around on on today's uh class in +particular not all of it but a lot of it + + align:start position:0% +particular not all of it but a lot of it + + + align:start position:0% +particular not all of it but a lot of it +what's happening within this newly + + align:start position:0% +what's happening within this newly + + + align:start position:0% +what's happening within this newly +unified country called Germany we saw + + align:start position:0% +unified country called Germany we saw + + + align:start position:0% +unified country called Germany we saw +this a few times there was no country of + + align:start position:0% +this a few times there was no country of + + + align:start position:0% +this a few times there was no country of +Germany until 1871 they were + + align:start position:0% +Germany until 1871 they were + + + align:start position:0% +Germany until 1871 they were +german-speaking territories but a single + + align:start position:0% +german-speaking territories but a single + + + align:start position:0% +german-speaking territories but a single +unified National country called Germany + + align:start position:0% +unified National country called Germany + + + align:start position:0% +unified National country called Germany +emerged really in out as one outcome of + + align:start position:0% +emerged really in out as one outcome of + + + align:start position:0% +emerged really in out as one outcome of +the franco-prussian war the but the + + align:start position:0% +the franco-prussian war the but the + + + align:start position:0% +the franco-prussian war the but the +Prussian State war against the country + + align:start position:0% +Prussian State war against the country + + + align:start position:0% +Prussian State war against the country +of France + + align:start position:0% +of France + + + align:start position:0% +of France +not too long before Einstein himself was + + align:start position:0% +not too long before Einstein himself was + + + align:start position:0% +not too long before Einstein himself was +born one of the things that the new + + align:start position:0% +born one of the things that the new + + + align:start position:0% +born one of the things that the new +country of Germany began to do was to + + align:start position:0% +country of Germany began to do was to + + + align:start position:0% +country of Germany began to do was to +invest very aggressively in a program of + + align:start position:0% +invest very aggressively in a program of + + + align:start position:0% +invest very aggressively in a program of +rapid industrialization once it became a + + align:start position:0% +rapid industrialization once it became a + + + align:start position:0% +rapid industrialization once it became a +single unified country the new leaders + + align:start position:0% +single unified country the new leaders + + + align:start position:0% +single unified country the new leaders +of the country looked around and and + + align:start position:0% +of the country looked around and and + + + align:start position:0% +of the country looked around and and +were concerned that they were falling + + align:start position:0% +were concerned that they were falling + + + align:start position:0% +were concerned that they were falling +far behind other European Neighbors in + + align:start position:0% +far behind other European Neighbors in + + + align:start position:0% +far behind other European Neighbors in +basic industrial capacity especially + + align:start position:0% +basic industrial capacity especially + + + align:start position:0% +basic industrial capacity especially +Britain to well to some degree they + + align:start position:0% +Britain to well to some degree they + + + align:start position:0% +Britain to well to some degree they +worried about France so they had + + align:start position:0% +worried about France so they had + + + align:start position:0% +worried about France so they had +prevailed in the in the recent War + + align:start position:0% +prevailed in the in the recent War + + + align:start position:0% +prevailed in the in the recent War +so the country begins investing quite a + + align:start position:0% +so the country begins investing quite a + + + align:start position:0% +so the country begins investing quite a +lot in in industrialization that often + + align:start position:0% +lot in in industrialization that often + + + align:start position:0% +lot in in industrialization that often +meant investing in science and + + align:start position:0% +meant investing in science and + + + align:start position:0% +meant investing in science and +technology what we would Now call + + align:start position:0% +technology what we would Now call + + + align:start position:0% +technology what we would Now call +science and engineering + + align:start position:0% +science and engineering + + + align:start position:0% +science and engineering +so a few years into this new country's + + align:start position:0% +so a few years into this new country's + + + align:start position:0% +so a few years into this new country's +life its existence the leaders put + + align:start position:0% +life its existence the leaders put + + + align:start position:0% +life its existence the leaders put +together a new kind of Institute not + + align:start position:0% +together a new kind of Institute not + + + align:start position:0% +together a new kind of Institute not +just new to Germany kind of knew even + + align:start position:0% +just new to Germany kind of knew even + + + align:start position:0% +just new to Germany kind of knew even +across Europe especially designed + + align:start position:0% +across Europe especially designed + + + align:start position:0% +across Europe especially designed +government-funded Institute called the + + align:start position:0% +government-funded Institute called the + + + align:start position:0% +government-funded Institute called the +physic College technician hi seanstalk + + align:start position:0% +physic College technician hi seanstalk + + + align:start position:0% +physic College technician hi seanstalk +which is fun to say we can just call it + + align:start position:0% +which is fun to say we can just call it + + + align:start position:0% +which is fun to say we can just call it +by its initials of PTR that really stood + + align:start position:0% +by its initials of PTR that really stood + + + align:start position:0% +by its initials of PTR that really stood +for the Imperial or the kind of German + + align:start position:0% +for the Imperial or the kind of German + + + align:start position:0% +for the Imperial or the kind of German +National physical Technical Institute + + align:start position:0% +National physical Technical Institute + + + align:start position:0% +National physical Technical Institute +the PTR + + align:start position:0% +the PTR + + + align:start position:0% +the PTR +the idea was that this new kind of space + + align:start position:0% +the idea was that this new kind of space + + + align:start position:0% +the idea was that this new kind of space +this new institution should foster + + align:start position:0% +this new institution should foster + + + align:start position:0% +this new institution should foster +several kinds of research and try to get + + align:start position:0% +several kinds of research and try to get + + + align:start position:0% +several kinds of research and try to get +them kind of talking together to really + + align:start position:0% +them kind of talking together to really + + + align:start position:0% +them kind of talking together to really +help jump start what the country's + + align:start position:0% +help jump start what the country's + + + align:start position:0% +help jump start what the country's +leaders hope to be this uh this uh very + + align:start position:0% +leaders hope to be this uh this uh very + + + align:start position:0% +leaders hope to be this uh this uh very +rapid uh pace of industrialization so + + align:start position:0% +rapid uh pace of industrialization so + + + align:start position:0% +rapid uh pace of industrialization so +the PTR was designed on purpose to + + align:start position:0% +the PTR was designed on purpose to + + + align:start position:0% +the PTR was designed on purpose to +foster a search into basic science into + + align:start position:0% +foster a search into basic science into + + + align:start position:0% +foster a search into basic science into +a kind of curiosity driven research in + + align:start position:0% +a kind of curiosity driven research in + + + align:start position:0% +a kind of curiosity driven research in +physics and chemistry in related areas + + align:start position:0% +physics and chemistry in related areas + + + align:start position:0% +physics and chemistry in related areas +but also uh also support work in applied + + align:start position:0% +but also uh also support work in applied + + + align:start position:0% +but also uh also support work in applied +research and Industrial Development so + + align:start position:0% +research and Industrial Development so + + + align:start position:0% +research and Industrial Development so +it's pretty similar to what would soon + + align:start position:0% +it's pretty similar to what would soon + + + align:start position:0% +it's pretty similar to what would soon +be developed in the United States it was + + align:start position:0% +be developed in the United States it was + + + align:start position:0% +be developed in the United States it was +originally called the U.S Bureau of + + align:start position:0% +originally called the U.S Bureau of + + + align:start position:0% +originally called the U.S Bureau of +Standards now you might know it by the + + align:start position:0% +Standards now you might know it by the + + + align:start position:0% +Standards now you might know it by the +name + + align:start position:0% +name + + + align:start position:0% +name +the National Institute of Standards and + + align:start position:0% +the National Institute of Standards and + + + align:start position:0% +the National Institute of Standards and +technology or nist which has several + + align:start position:0% +technology or nist which has several + + + align:start position:0% +technology or nist which has several +kind of National Laboratory sites + + align:start position:0% +kind of National Laboratory sites + + + align:start position:0% +kind of National Laboratory sites +throughout the US the PTR was in that + + align:start position:0% +throughout the US the PTR was in that + + + align:start position:0% +throughout the US the PTR was in that +mold it was really forming that mold + + align:start position:0% +mold it was really forming that mold + + + align:start position:0% +mold it was really forming that mold +government sponsored to try to to + + align:start position:0% +government sponsored to try to to + + + align:start position:0% +government sponsored to try to to +encourage certain kinds of research both + + align:start position:0% +encourage certain kinds of research both + + + align:start position:0% +encourage certain kinds of research both +in basic sciences and uh industrial + + align:start position:0% +in basic sciences and uh industrial + + + align:start position:0% +in basic sciences and uh industrial +applications + + align:start position:0% +applications + + + align:start position:0% +applications +one of the earliest pressing priorities + + align:start position:0% +one of the earliest pressing priorities + + + align:start position:0% +one of the earliest pressing priorities +for this new Institute + + align:start position:0% +for this new Institute + + + align:start position:0% +for this new Institute +was to evaluate competing proposals for + + align:start position:0% +was to evaluate competing proposals for + + + align:start position:0% +was to evaluate competing proposals for +things for Public Works projects like + + align:start position:0% +things for Public Works projects like + + + align:start position:0% +things for Public Works projects like +large-scale electric street lighting + + align:start position:0% +large-scale electric street lighting + + + align:start position:0% +large-scale electric street lighting +some of you may know the incandescent + + align:start position:0% +some of you may know the incandescent + + + align:start position:0% +some of you may know the incandescent +light bulb electric light bulbs were + + align:start position:0% +light bulb electric light bulbs were + + + align:start position:0% +light bulb electric light bulbs were +actually quite new people think about + + align:start position:0% +actually quite new people think about + + + align:start position:0% +actually quite new people think about +people like Thomas Edison + + align:start position:0% +people like Thomas Edison + + + align:start position:0% +people like Thomas Edison +and others in the United States similar + + align:start position:0% +and others in the United States similar + + + align:start position:0% +and others in the United States similar +work going on elsewhere and one of the + + align:start position:0% +work going on elsewhere and one of the + + + align:start position:0% +work going on elsewhere and one of the +earliest efforts was to put this new + + align:start position:0% +earliest efforts was to put this new + + + align:start position:0% +earliest efforts was to put this new +kind of Technology an incandescent light + + align:start position:0% +kind of Technology an incandescent light + + + align:start position:0% +kind of Technology an incandescent light +bulb and electric light bulb into use in + + align:start position:0% +bulb and electric light bulb into use in + + + align:start position:0% +bulb and electric light bulb into use in +kind of public spaces imagine the + + align:start position:0% +kind of public spaces imagine the + + + align:start position:0% +kind of public spaces imagine the +difference for City Life for Commerce + + align:start position:0% +difference for City Life for Commerce + + + align:start position:0% +difference for City Life for Commerce +for uh for for communities in general if + + align:start position:0% +for uh for for communities in general if + + + align:start position:0% +for uh for for communities in general if +cities were at pitch dark uh just as + + align:start position:0% +cities were at pitch dark uh just as + + + align:start position:0% +cities were at pitch dark uh just as +soon as the sun went down now of course + + align:start position:0% +soon as the sun went down now of course + + + align:start position:0% +soon as the sun went down now of course +there were many many competing ideas + + align:start position:0% +there were many many competing ideas + + + align:start position:0% +there were many many competing ideas +about how to do that how to do it + + align:start position:0% +about how to do that how to do it + + + align:start position:0% +about how to do that how to do it +efficiently how to make the right kinds + + align:start position:0% +efficiently how to make the right kinds + + + align:start position:0% +efficiently how to make the right kinds +of bulbs that could give out a lot of + + align:start position:0% +of bulbs that could give out a lot of + + + align:start position:0% +of bulbs that could give out a lot of +light with hopefully not too much power + + align:start position:0% +light with hopefully not too much power + + + align:start position:0% +light with hopefully not too much power +usage and so on and so one of the first + + align:start position:0% +usage and so on and so one of the first + + + align:start position:0% +usage and so on and so one of the first +questions of his new PTR had to wrestle + + align:start position:0% +questions of his new PTR had to wrestle + + + align:start position:0% +questions of his new PTR had to wrestle +with was how to compare these competing + + align:start position:0% +with was how to compare these competing + + + align:start position:0% +with was how to compare these competing +proposals for things like electric + + align:start position:0% +proposals for things like electric + + + align:start position:0% +proposals for things like electric +street lighting what they were asking + + align:start position:0% +street lighting what they were asking + + + align:start position:0% +street lighting what they were asking +about is how can you measure the amount + + align:start position:0% +about is how can you measure the amount + + + align:start position:0% +about is how can you measure the amount +of light that comes out from these very + + align:start position:0% +of light that comes out from these very + + + align:start position:0% +of light that comes out from these very +hot filaments in these electric bulbs + + align:start position:0% +hot filaments in these electric bulbs + + + align:start position:0% +hot filaments in these electric bulbs +now people had known for a long long + + align:start position:0% +now people had known for a long long + + + align:start position:0% +now people had known for a long long +time long before the PTR humans had + + align:start position:0% +time long before the PTR humans had + + + align:start position:0% +time long before the PTR humans had +known that when materials are heated up + + align:start position:0% +known that when materials are heated up + + + align:start position:0% +known that when materials are heated up +to a sufficiently high temperature + + align:start position:0% +to a sufficiently high temperature + + + align:start position:0% +to a sufficiently high temperature +they'll begin to Glow they'll give off + + align:start position:0% +they'll begin to Glow they'll give off + + + align:start position:0% +they'll begin to Glow they'll give off +some kind of radiation some light think + + align:start position:0% +some kind of radiation some light think + + + align:start position:0% +some kind of radiation some light think +about very casual observations like uh + + align:start position:0% +about very casual observations like uh + + + align:start position:0% +about very casual observations like uh +Embers glowing in a fireplace or + + align:start position:0% +Embers glowing in a fireplace or + + + align:start position:0% +Embers glowing in a fireplace or +charcoals on a grill or now tragically + + align:start position:0% +charcoals on a grill or now tragically + + + align:start position:0% +charcoals on a grill or now tragically +the photographs we see from these + + align:start position:0% +the photographs we see from these + + + align:start position:0% +the photographs we see from these +horrific uh you know forest fires out in + + align:start position:0% +horrific uh you know forest fires out in + + + align:start position:0% +horrific uh you know forest fires out in +California and up and down the West + + align:start position:0% +California and up and down the West + + + align:start position:0% +California and up and down the West +Coast when you heat stuff up to a high + + align:start position:0% +Coast when you heat stuff up to a high + + + align:start position:0% +Coast when you heat stuff up to a high +enough temperature it will give off + + align:start position:0% +enough temperature it will give off + + + align:start position:0% +enough temperature it will give off +light it will glow + + align:start position:0% +light it will glow + + + align:start position:0% +light it will glow +and in fact the color of the emitted + + align:start position:0% +and in fact the color of the emitted + + + align:start position:0% +and in fact the color of the emitted +light shifts with the temperature to + + align:start position:0% +light shifts with the temperature to + + + align:start position:0% +light shifts with the temperature to +which the object has been heated so the + + align:start position:0% +which the object has been heated so the + + + align:start position:0% +which the object has been heated so the +colors the main frequencies of light + + align:start position:0% +colors the main frequencies of light + + + align:start position:0% +colors the main frequencies of light +that dominate that glow will shift uh + + align:start position:0% +that dominate that glow will shift uh + + + align:start position:0% +that dominate that glow will shift uh +with temperature and that was again + + align:start position:0% +with temperature and that was again + + + align:start position:0% +with temperature and that was again +something was known kind of casually + + align:start position:0% +something was known kind of casually + + + align:start position:0% +something was known kind of casually +long before it was a PTR + + align:start position:0% +long before it was a PTR + + + align:start position:0% +long before it was a PTR +well that feeds into this very specific + + align:start position:0% +well that feeds into this very specific + + + align:start position:0% +well that feeds into this very specific +work at this new Institute the PTR + + align:start position:0% +work at this new Institute the PTR + + + align:start position:0% +work at this new Institute the PTR +because one of the group one of the + + align:start position:0% +because one of the group one of the + + + align:start position:0% +because one of the group one of the +tasks of the new group was to figure out + + align:start position:0% +tasks of the new group was to figure out + + + align:start position:0% +tasks of the new group was to figure out +calibrations for these different kinds + + align:start position:0% +calibrations for these different kinds + + + align:start position:0% +calibrations for these different kinds +of electric light + + align:start position:0% +of electric light + + + align:start position:0% +of electric light +Technologies these proposals and what + + align:start position:0% +Technologies these proposals and what + + + align:start position:0% +Technologies these proposals and what +the pgr researchers began to notice was + + align:start position:0% +the pgr researchers began to notice was + + + align:start position:0% +the pgr researchers began to notice was +it looked like there was a kind of + + align:start position:0% +it looked like there was a kind of + + + align:start position:0% +it looked like there was a kind of +universal or shared pattern in the kind + + align:start position:0% +universal or shared pattern in the kind + + + align:start position:0% +universal or shared pattern in the kind +of light in the pattern of light that + + align:start position:0% +of light in the pattern of light that + + + align:start position:0% +of light in the pattern of light that +came out from various objects when they + + align:start position:0% +came out from various objects when they + + + align:start position:0% +came out from various objects when they +were heated to high temperatures and + + align:start position:0% +were heated to high temperatures and + + + align:start position:0% +were heated to high temperatures and +they thought it was Universal because it + + align:start position:0% +they thought it was Universal because it + + + align:start position:0% +they thought it was Universal because it +looked like the pattern of Light how + + align:start position:0% +looked like the pattern of Light how + + + align:start position:0% +looked like the pattern of Light how +much light came out at which particular + + align:start position:0% +much light came out at which particular + + + align:start position:0% +much light came out at which particular +colors + + align:start position:0% +colors + + + align:start position:0% +colors +seemed to depend only on the temperature + + align:start position:0% +seemed to depend only on the temperature + + + align:start position:0% +seemed to depend only on the temperature +to which those materials have been + + align:start position:0% +to which those materials have been + + + align:start position:0% +to which those materials have been +heated but not on the mechanic on the + + align:start position:0% +heated but not on the mechanic on the + + + align:start position:0% +heated but not on the mechanic on the +material kind of chemical makeup of the + + align:start position:0% +material kind of chemical makeup of the + + + align:start position:0% +material kind of chemical makeup of the +materials themselves different kinds of + + align:start position:0% +materials themselves different kinds of + + + align:start position:0% +materials themselves different kinds of +filaments for example even if they were + + align:start position:0% +filaments for example even if they were + + + align:start position:0% +filaments for example even if they were +made up from an entirely different + + align:start position:0% +made up from an entirely different + + + align:start position:0% +made up from an entirely different +atoms and molecules would glow with the + + align:start position:0% +atoms and molecules would glow with the + + + align:start position:0% +atoms and molecules would glow with the +same kind of pattern once they were + + align:start position:0% +same kind of pattern once they were + + + align:start position:0% +same kind of pattern once they were +heated to a sufficiently high + + align:start position:0% +heated to a sufficiently high + + + align:start position:0% +heated to a sufficiently high +temperature at least it looked like that + + align:start position:0% +temperature at least it looked like that + + + align:start position:0% +temperature at least it looked like that +might be the case in these early tests + + align:start position:0% +might be the case in these early tests + + + align:start position:0% +might be the case in these early tests +to calibrate these different kinds of + + align:start position:0% +to calibrate these different kinds of + + + align:start position:0% +to calibrate these different kinds of +electric light fixtures and so on + + align:start position:0% +electric light fixtures and so on + + + align:start position:0% +electric light fixtures and so on +so these researchers began to postulate + + align:start position:0% +so these researchers began to postulate + + + align:start position:0% +so these researchers began to postulate +that there was some ideal so-called + + align:start position:0% +that there was some ideal so-called + + + align:start position:0% +that there was some ideal so-called +black body the idea was imagine an + + align:start position:0% +black body the idea was imagine an + + + align:start position:0% +black body the idea was imagine an +object that absorbed all the light that + + align:start position:0% +object that absorbed all the light that + + + align:start position:0% +object that absorbed all the light that +fell upon it and reflected none back so + + align:start position:0% +fell upon it and reflected none back so + + + align:start position:0% +fell upon it and reflected none back so +it would appeal to our eyes to be black + + align:start position:0% +it would appeal to our eyes to be black + + + align:start position:0% +it would appeal to our eyes to be black +it would reflect no light at all we'd + + align:start position:0% +it would reflect no light at all we'd + + + align:start position:0% +it would reflect no light at all we'd +see it as emitting uh reflecting no + + align:start position:0% +see it as emitting uh reflecting no + + + align:start position:0% +see it as emitting uh reflecting no +light at all + + align:start position:0% +light at all + + + align:start position:0% +light at all +so so you want to sort of remove any + + align:start position:0% +so so you want to sort of remove any + + + align:start position:0% +so so you want to sort of remove any +accidents of the kind of light that + + align:start position:0% +accidents of the kind of light that + + + align:start position:0% +accidents of the kind of light that +might have shown on it and concentrate + + align:start position:0% +might have shown on it and concentrate + + + align:start position:0% +might have shown on it and concentrate +on the light being emitted by this + + align:start position:0% +on the light being emitted by this + + + align:start position:0% +on the light being emitted by this +so-called black body when you heat that + + align:start position:0% +so-called black body when you heat that + + + align:start position:0% +so-called black body when you heat that +object up to a high temperature + + align:start position:0% +object up to a high temperature + + + align:start position:0% +object up to a high temperature +and it shouldn't have mattered whether + + align:start position:0% +and it shouldn't have mattered whether + + + align:start position:0% +and it shouldn't have mattered whether +the black body was actually made of wood + + align:start position:0% +the black body was actually made of wood + + + align:start position:0% +the black body was actually made of wood +or charcoal or anything else if it + + align:start position:0% +or charcoal or anything else if it + + + align:start position:0% +or charcoal or anything else if it +really is a universal glow that you can + + align:start position:0% +really is a universal glow that you can + + + align:start position:0% +really is a universal glow that you can +imagine is idealized kind of otherwise + + align:start position:0% +imagine is idealized kind of otherwise + + + align:start position:0% +imagine is idealized kind of otherwise +unspecified kind of object of black body + + align:start position:0% +unspecified kind of object of black body + + + align:start position:0% +unspecified kind of object of black body +and therefore this when you heat this + + align:start position:0% +and therefore this when you heat this + + + align:start position:0% +and therefore this when you heat this +object this mysterious or hypothetical + + align:start position:0% +object this mysterious or hypothetical + + + align:start position:0% +object this mysterious or hypothetical +object up to a sufficiently high + + align:start position:0% +object up to a sufficiently high + + + align:start position:0% +object up to a sufficiently high +temperature the pattern of light that + + align:start position:0% +temperature the pattern of light that + + + align:start position:0% +temperature the pattern of light that +would be emitted uh should tell you + + align:start position:0% +would be emitted uh should tell you + + + align:start position:0% +would be emitted uh should tell you +something about about Universal + + align:start position:0% +something about about Universal + + + align:start position:0% +something about about Universal +properties not The Accidental features + + align:start position:0% +properties not The Accidental features + + + align:start position:0% +properties not The Accidental features +of this or that chemical material + + align:start position:0% +of this or that chemical material + + + align:start position:0% +of this or that chemical material +so this Universal black body Spectrum or + + align:start position:0% +so this Universal black body Spectrum or + + + align:start position:0% +so this Universal black body Spectrum or +at least the hypothesis there might be + + align:start position:0% +at least the hypothesis there might be + + + align:start position:0% +at least the hypothesis there might be +this Universal Behavior that's + + align:start position:0% +this Universal Behavior that's + + + align:start position:0% +this Universal Behavior that's +interesting for at least two reasons of + + align:start position:0% +interesting for at least two reasons of + + + align:start position:0% +interesting for at least two reasons of +exactly the kinds of things that this + + align:start position:0% +exactly the kinds of things that this + + + align:start position:0% +exactly the kinds of things that this +this new PTR had been set up um to to + + align:start position:0% +this new PTR had been set up um to to + + + align:start position:0% +this new PTR had been set up um to to +Foster this could be really useful for + + align:start position:0% +Foster this could be really useful for + + + align:start position:0% +Foster this could be really useful for +calibrations and standardization take + + align:start position:0% +calibrations and standardization take + + + align:start position:0% +calibrations and standardization take +any new um electric light fixture or + + align:start position:0% +any new um electric light fixture or + + + align:start position:0% +any new um electric light fixture or +similar device you should now have a + + align:start position:0% +similar device you should now have a + + + align:start position:0% +similar device you should now have a +universal standard against which one + + align:start position:0% +universal standard against which one + + + align:start position:0% +universal standard against which one +could measure its own light output what + + align:start position:0% +could measure its own light output what + + + align:start position:0% +could measure its own light output what +pattern of light would come out uh from + + align:start position:0% +pattern of light would come out uh from + + + align:start position:0% +pattern of light would come out uh from +say this or that filament because now + + align:start position:0% +say this or that filament because now + + + align:start position:0% +say this or that filament because now +you have a universal standard with which + + align:start position:0% +you have a universal standard with which + + + align:start position:0% +you have a universal standard with which +to compare it it also suggested this + + align:start position:0% +to compare it it also suggested this + + + align:start position:0% +to compare it it also suggested this +might tell us something deeply + + align:start position:0% +might tell us something deeply + + + align:start position:0% +might tell us something deeply +fundamental and very basic about the + + align:start position:0% +fundamental and very basic about the + + + align:start position:0% +fundamental and very basic about the +interactions between light and matter it + + align:start position:0% +interactions between light and matter it + + + align:start position:0% +interactions between light and matter it +shouldn't matter whether you're talking + + align:start position:0% +shouldn't matter whether you're talking + + + align:start position:0% +shouldn't matter whether you're talking +about this kind of material fulfillment + + align:start position:0% +about this kind of material fulfillment + + + align:start position:0% +about this kind of material fulfillment +or that kind this tells us perhaps + + align:start position:0% +or that kind this tells us perhaps + + + align:start position:0% +or that kind this tells us perhaps +something very Universal about light and + + align:start position:0% +something very Universal about light and + + + align:start position:0% +something very Universal about light and +matter at its at their core + + align:start position:0% +matter at its at their core + + + align:start position:0% +matter at its at their core +so these researchers at this newly uh + + align:start position:0% +so these researchers at this newly uh + + + align:start position:0% +so these researchers at this newly uh +generously funded physical College + + align:start position:0% +generously funded physical College + + + align:start position:0% +generously funded physical College +Technologies to help the PTR they began + + align:start position:0% +Technologies to help the PTR they began + + + align:start position:0% +Technologies to help the PTR they began +conducting more and more sensitive + + align:start position:0% +conducting more and more sensitive + + + align:start position:0% +conducting more and more sensitive +experiments on the pattern of light what + + align:start position:0% +experiments on the pattern of light what + + + align:start position:0% +experiments on the pattern of light what +became known as the spectrum of light + + align:start position:0% +became known as the spectrum of light + + + align:start position:0% +became known as the spectrum of light +that was emitted from these black bodies + + align:start position:0% +that was emitted from these black bodies + + + align:start position:0% +that was emitted from these black bodies +over the course of the 1880s and 1890s + + align:start position:0% +over the course of the 1880s and 1890s + + + align:start position:0% +over the course of the 1880s and 1890s +soon after the PTR itself had been + + align:start position:0% +soon after the PTR itself had been + + + align:start position:0% +soon after the PTR itself had been +founded and they began finding curves + + align:start position:0% +founded and they began finding curves + + + align:start position:0% +founded and they began finding curves +that looked like this now in the early + + align:start position:0% +that looked like this now in the early + + + align:start position:0% +that looked like this now in the early +data this was an example of real + + align:start position:0% +data this was an example of real + + + align:start position:0% +data this was an example of real +published data from the pgr researchers + + align:start position:0% +published data from the pgr researchers + + + align:start position:0% +published data from the pgr researchers +number in Princeton + + align:start position:0% +number in Princeton + + + align:start position:0% +number in Princeton +they often would plot the Spectrum the + + align:start position:0% +they often would plot the Spectrum the + + + align:start position:0% +they often would plot the Spectrum the +amount of energy came out as one vary + + align:start position:0% +amount of energy came out as one vary + + + align:start position:0% +amount of energy came out as one vary +the wavelength of light typically these + + align:start position:0% +the wavelength of light typically these + + + align:start position:0% +the wavelength of light typically these +days we tend to characterize in terms of + + align:start position:0% +days we tend to characterize in terms of + + + align:start position:0% +days we tend to characterize in terms of +the frequency but remember that's an + + align:start position:0% +the frequency but remember that's an + + + align:start position:0% +the frequency but remember that's an +easy Choice a trade-off we can always + + align:start position:0% +easy Choice a trade-off we can always + + + align:start position:0% +easy Choice a trade-off we can always +relate the frequency of the light that + + align:start position:0% +relate the frequency of the light that + + + align:start position:0% +relate the frequency of the light that +comes out new we'll use the Greek letter + + align:start position:0% +comes out new we'll use the Greek letter + + + align:start position:0% +comes out new we'll use the Greek letter +new that's inversely proportional to the + + align:start position:0% +new that's inversely proportional to the + + + align:start position:0% +new that's inversely proportional to the +wavelength like in these data here and + + align:start position:0% +wavelength like in these data here and + + + align:start position:0% +wavelength like in these data here and +the consonant proportionality is just + + align:start position:0% +the consonant proportionality is just + + + align:start position:0% +the consonant proportionality is just +given by the speed at which those light + + align:start position:0% +given by the speed at which those light + + + align:start position:0% +given by the speed at which those light +waves are traveling the speed of light + + align:start position:0% +waves are traveling the speed of light + + + align:start position:0% +waves are traveling the speed of light +so let's look at this curve Uh u u is a + + align:start position:0% +so let's look at this curve Uh u u is a + + + align:start position:0% +so let's look at this curve Uh u u is a +certain kind of quantity called a + + align:start position:0% +certain kind of quantity called a + + + align:start position:0% +certain kind of quantity called a +spectral energy density + + align:start position:0% +spectral energy density + + + align:start position:0% +spectral energy density +that's kind of a mouthful and again I go + + align:start position:0% +that's kind of a mouthful and again I go + + + align:start position:0% +that's kind of a mouthful and again I go +through some distance some more details + + align:start position:0% +through some distance some more details + + + align:start position:0% +through some distance some more details +in the optional lecture notes what this + + align:start position:0% +in the optional lecture notes what this + + + align:start position:0% +in the optional lecture notes what this +curve what these curves are showing is + + align:start position:0% +curve what these curves are showing is + + + align:start position:0% +curve what these curves are showing is +the amount of energy per unit volume and + + align:start position:0% +the amount of energy per unit volume and + + + align:start position:0% +the amount of energy per unit volume and +in some region of space + + align:start position:0% +in some region of space + + + align:start position:0% +in some region of space +per frequency so how much light gets + + align:start position:0% +per frequency so how much light gets + + + align:start position:0% +per frequency so how much light gets +shown out in the form of how much energy + + align:start position:0% +shown out in the form of how much energy + + + align:start position:0% +shown out in the form of how much energy +get shown out in the form of radiation + + align:start position:0% +get shown out in the form of radiation + + + align:start position:0% +get shown out in the form of radiation +in some box of fixed size within per + + align:start position:0% +in some box of fixed size within per + + + align:start position:0% +in some box of fixed size within per +unit volume as you vary the color of the + + align:start position:0% +unit volume as you vary the color of the + + + align:start position:0% +unit volume as you vary the color of the +light and so it suggests you get a + + align:start position:0% +light and so it suggests you get a + + + align:start position:0% +light and so it suggests you get a +certain amount of energy radiated for + + align:start position:0% +certain amount of energy radiated for + + + align:start position:0% +certain amount of energy radiated for +one color as you vary the frequency of + + align:start position:0% +one color as you vary the frequency of + + + align:start position:0% +one color as you vary the frequency of +the light a different amount of energy + + align:start position:0% +the light a different amount of energy + + + align:start position:0% +the light a different amount of energy +comes out in this case more energy as + + align:start position:0% +comes out in this case more energy as + + + align:start position:0% +comes out in this case more energy as +you go to a higher frequency different + + align:start position:0% +you go to a higher frequency different + + + align:start position:0% +you go to a higher frequency different +color and so on + + align:start position:0% +color and so on + + + align:start position:0% +color and so on +and what it was uh what what the + + align:start position:0% +and what it was uh what what the + + + align:start position:0% +and what it was uh what what the +researchers kept finding was that the + + align:start position:0% +researchers kept finding was that the + + + align:start position:0% +researchers kept finding was that the +nature of this curve depended only on + + align:start position:0% +nature of this curve depended only on + + + align:start position:0% +nature of this curve depended only on +the temperature to which the objects + + align:start position:0% +the temperature to which the objects + + + align:start position:0% +the temperature to which the objects +have been heated but not the material + + align:start position:0% +have been heated but not the material + + + align:start position:0% +have been heated but not the material +composition of those objects this + + align:start position:0% +composition of those objects this + + + align:start position:0% +composition of those objects this +Universal feature became more and more + + align:start position:0% +Universal feature became more and more + + + align:start position:0% +Universal feature became more and more +evidence as they conducted more and more + + align:start position:0% +evidence as they conducted more and more + + + align:start position:0% +evidence as they conducted more and more +tests + + align:start position:0% +tests + + + align:start position:0% +tests +and so this is a plot now showing the + + align:start position:0% +and so this is a plot now showing the + + + align:start position:0% +and so this is a plot now showing the +the form of this spectral energy density + + align:start position:0% +the form of this spectral energy density + + + align:start position:0% +the form of this spectral energy density +for three different temperatures it + + align:start position:0% +for three different temperatures it + + + align:start position:0% +for three different temperatures it +varies only with temperature it's + + align:start position:0% +varies only with temperature it's + + + align:start position:0% +varies only with temperature it's +considered a relatively low temperature + + align:start position:0% +considered a relatively low temperature + + + align:start position:0% +considered a relatively low temperature +here so medium temperature and some high + + align:start position:0% +here so medium temperature and some high + + + align:start position:0% +here so medium temperature and some high +temperature + + align:start position:0% +temperature + + + align:start position:0% +temperature +already we see the trend becomes pretty + + align:start position:0% +already we see the trend becomes pretty + + + align:start position:0% +already we see the trend becomes pretty +clear as you raise the temperature to + + align:start position:0% +clear as you raise the temperature to + + + align:start position:0% +clear as you raise the temperature to +which you've heated that black body that + + align:start position:0% +which you've heated that black body that + + + align:start position:0% +which you've heated that black body that +object the amount of energy that's + + align:start position:0% +object the amount of energy that's + + + align:start position:0% +object the amount of energy that's +radiated grows so you get more and more + + align:start position:0% +radiated grows so you get more and more + + + align:start position:0% +radiated grows so you get more and more +energy coming out the the area under + + align:start position:0% +energy coming out the the area under + + + align:start position:0% +energy coming out the the area under +this curve of the blue one is much + + align:start position:0% +this curve of the blue one is much + + + align:start position:0% +this curve of the blue one is much +larger than the area under the either + + align:start position:0% +larger than the area under the either + + + align:start position:0% +larger than the area under the either +the other curves + + align:start position:0% +the other curves + + + align:start position:0% +the other curves +total energy output where the intensity + + align:start position:0% +total energy output where the intensity + + + align:start position:0% +total energy output where the intensity +increases with temperature and the peak + + align:start position:0% +increases with temperature and the peak + + + align:start position:0% +increases with temperature and the peak +frequency the frequency at which which + + align:start position:0% +frequency the frequency at which which + + + align:start position:0% +frequency the frequency at which which +most energy gets emitted uh in the form + + align:start position:0% +most energy gets emitted uh in the form + + + align:start position:0% +most energy gets emitted uh in the form +of light that also shifts to higher and + + align:start position:0% +of light that also shifts to higher and + + + align:start position:0% +of light that also shifts to higher and +higher frequency so at a relatively low + + align:start position:0% +higher frequency so at a relatively low + + + align:start position:0% +higher frequency so at a relatively low +temperature the highest the peak + + align:start position:0% +temperature the highest the peak + + + align:start position:0% +temperature the highest the peak +frequency is a kind of reddish color as + + align:start position:0% +frequency is a kind of reddish color as + + + align:start position:0% +frequency is a kind of reddish color as +you increase the temperature it shifts + + align:start position:0% +you increase the temperature it shifts + + + align:start position:0% +you increase the temperature it shifts +through the Spectrum uh to our engine + + align:start position:0% +through the Spectrum uh to our engine + + + align:start position:0% +through the Spectrum uh to our engine +ultimately to the blue end so you have + + align:start position:0% +ultimately to the blue end so you have + + + align:start position:0% +ultimately to the blue end so you have +this pattern emerging + + align:start position:0% +this pattern emerging + + + align:start position:0% +this pattern emerging +so as the empirical pattern has these + + align:start position:0% +so as the empirical pattern has these + + + align:start position:0% +so as the empirical pattern has these +empirical measurements in the in the + + align:start position:0% +empirical measurements in the in the + + + align:start position:0% +empirical measurements in the in the +Laboratories became more and more clear + + align:start position:0% +Laboratories became more and more clear + + + align:start position:0% +Laboratories became more and more clear +how do you make sense of that pattern + + align:start position:0% +how do you make sense of that pattern + + + align:start position:0% +how do you make sense of that pattern +that actually was very very non-trivial + + align:start position:0% +that actually was very very non-trivial + + + align:start position:0% +that actually was very very non-trivial +that was not at all clear to these early + + align:start position:0% +that was not at all clear to these early + + + align:start position:0% +that was not at all clear to these early +researchers + + align:start position:0% +researchers + + + align:start position:0% +researchers +so one of the first to really delve into + + align:start position:0% +so one of the first to really delve into + + + align:start position:0% +so one of the first to really delve into +this try to get a theoretical + + align:start position:0% +this try to get a theoretical + + + align:start position:0% +this try to get a theoretical +explanation for that pattern was MOX + + align:start position:0% +explanation for that pattern was MOX + + + align:start position:0% +explanation for that pattern was MOX +plot so plug had only recently moved to + + align:start position:0% +plot so plug had only recently moved to + + + align:start position:0% +plot so plug had only recently moved to +Berlin he was one of the first people in + + align:start position:0% +Berlin he was one of the first people in + + + align:start position:0% +Berlin he was one of the first people in +all of Germany to have this full + + align:start position:0% +all of Germany to have this full + + + align:start position:0% +all of Germany to have this full +Professor this special ordinarius + + align:start position:0% +Professor this special ordinarius + + + align:start position:0% +Professor this special ordinarius +professor chair in theoretical physics + + align:start position:0% +professor chair in theoretical physics + + + align:start position:0% +professor chair in theoretical physics +remember we talked several weeks ago + + align:start position:0% +remember we talked several weeks ago + + + align:start position:0% +remember we talked several weeks ago +several classes ago that until the later + + align:start position:0% +several classes ago that until the later + + + align:start position:0% +several classes ago that until the later +years of the 19th century + + align:start position:0% +years of the 19th century + + + align:start position:0% +years of the 19th century +especially in the German language + + align:start position:0% +especially in the German language + + + align:start position:0% +especially in the German language +universities there will be one full + + align:start position:0% +universities there will be one full + + + align:start position:0% +universities there will be one full +Professor one ordinarius + + align:start position:0% +Professor one ordinarius + + + align:start position:0% +Professor one ordinarius +for all of physics and that person was + + align:start position:0% +for all of physics and that person was + + + align:start position:0% +for all of physics and that person was +sort of by default on experimental + + align:start position:0% +sort of by default on experimental + + + align:start position:0% +sort of by default on experimental +physicist only by the later Decades of + + align:start position:0% +physicist only by the later Decades of + + + align:start position:0% +physicist only by the later Decades of +the 19th century where there are + + align:start position:0% +the 19th century where there are + + + align:start position:0% +the 19th century where there are +sometimes two full professors of physics + + align:start position:0% +sometimes two full professors of physics + + + align:start position:0% +sometimes two full professors of physics +one to handle experiment and one for + + align:start position:0% +one to handle experiment and one for + + + align:start position:0% +one to handle experiment and one for +Theory clock was one of these early + + align:start position:0% +Theory clock was one of these early + + + align:start position:0% +Theory clock was one of these early +ordinary suppressors of theoretical + + align:start position:0% +ordinary suppressors of theoretical + + + align:start position:0% +ordinary suppressors of theoretical +physics in Berlin starting in the early + + align:start position:0% +physics in Berlin starting in the early + + + align:start position:0% +physics in Berlin starting in the early +1890s he was not at the PTR but he was + + align:start position:0% +1890s he was not at the PTR but he was + + + align:start position:0% +1890s he was not at the PTR but he was +nearby and he was in touch with his + + align:start position:0% +nearby and he was in touch with his + + + align:start position:0% +nearby and he was in touch with his +colleagues there clock was an expert in + + align:start position:0% +colleagues there clock was an expert in + + + align:start position:0% +colleagues there clock was an expert in +particular + + align:start position:0% +particular + + + align:start position:0% +particular +on the new work on statistical mechanics + + align:start position:0% +on the new work on statistical mechanics + + + align:start position:0% +on the new work on statistical mechanics +by people like James Clark Maxwell and + + align:start position:0% +by people like James Clark Maxwell and + + + align:start position:0% +by people like James Clark Maxwell and +Elizabeth Walton and others how do you + + align:start position:0% +Elizabeth Walton and others how do you + + + align:start position:0% +Elizabeth Walton and others how do you +make sense of large collections of + + align:start position:0% +make sense of large collections of + + + align:start position:0% +make sense of large collections of +objects like uh like molecules in a gas + + align:start position:0% +objects like uh like molecules in a gas + + + align:start position:0% +objects like uh like molecules in a gas +how do you assess their Collective + + align:start position:0% +how do you assess their Collective + + + align:start position:0% +how do you assess their Collective +property that's what you focus on + + align:start position:0% +property that's what you focus on + + + align:start position:0% +property that's what you focus on +because he was now closed in PTR he + + align:start position:0% +because he was now closed in PTR he + + + align:start position:0% +because he was now closed in PTR he +began paying more and more attention to + + align:start position:0% +began paying more and more attention to + + + align:start position:0% +began paying more and more attention to +this black body research as well and he + + align:start position:0% +this black body research as well and he + + + align:start position:0% +this black body research as well and he +realizes many others did it was really + + align:start position:0% +realizes many others did it was really + + + align:start position:0% +realizes many others did it was really +really hard to make sense of his + + align:start position:0% +really hard to make sense of his + + + align:start position:0% +really hard to make sense of his +characteristic pattern that seemingly + + align:start position:0% +characteristic pattern that seemingly + + + align:start position:0% +characteristic pattern that seemingly +Universal shape of this black body + + align:start position:0% +Universal shape of this black body + + + align:start position:0% +Universal shape of this black body +Spectrum uh the amount of energy per + + align:start position:0% +Spectrum uh the amount of energy per + + + align:start position:0% +Spectrum uh the amount of energy per +unit volume per frequency and in fact if + + align:start position:0% +unit volume per frequency and in fact if + + + align:start position:0% +unit volume per frequency and in fact if +you used quite standard by that point + + align:start position:0% +you used quite standard by that point + + + align:start position:0% +you used quite standard by that point +very familiar arguments from people like + + align:start position:0% +very familiar arguments from people like + + + align:start position:0% +very familiar arguments from people like +boltzmann and Maxwell the kind of people + + align:start position:0% +boltzmann and Maxwell the kind of people + + + align:start position:0% +boltzmann and Maxwell the kind of people +whose work plaque was an expert in + + align:start position:0% +whose work plaque was an expert in + + + align:start position:0% +whose work plaque was an expert in +studying + + align:start position:0% +studying + + + align:start position:0% +studying +you should predict a very different + + align:start position:0% +you should predict a very different + + + align:start position:0% +you should predict a very different +behavior from first principles in fact + + align:start position:0% +behavior from first principles in fact + + + align:start position:0% +behavior from first principles in fact +it should look like this this dashed + + align:start position:0% +it should look like this this dashed + + + align:start position:0% +it should look like this this dashed +purple curve which doesn't look anything + + align:start position:0% +purple curve which doesn't look anything + + + align:start position:0% +purple curve which doesn't look anything +like the ultimate curve that was + + align:start position:0% +like the ultimate curve that was + + + align:start position:0% +like the ultimate curve that was +measured they agree very well at very + + align:start position:0% +measured they agree very well at very + + + align:start position:0% +measured they agree very well at very +low frequencies they both overlap here + + align:start position:0% +low frequencies they both overlap here + + + align:start position:0% +low frequencies they both overlap here +but then you see a very significant + + align:start position:0% +but then you see a very significant + + + align:start position:0% +but then you see a very significant +difference between their patterns and in + + align:start position:0% +difference between their patterns and in + + + align:start position:0% +difference between their patterns and in +fact this purple one became known as the + + align:start position:0% +fact this purple one became known as the + + + align:start position:0% +fact this purple one became known as the +ultraviolet catastrophe I love that term + + align:start position:0% +ultraviolet catastrophe I love that term + + + align:start position:0% +ultraviolet catastrophe I love that term +it's a catastrophe + + align:start position:0% +it's a catastrophe + + + align:start position:0% +it's a catastrophe +if you follow the then standard + + align:start position:0% +if you follow the then standard + + + align:start position:0% +if you follow the then standard +arguments and I go through these again + + align:start position:0% +arguments and I go through these again + + + align:start position:0% +arguments and I go through these again +in some more detail on those optional + + align:start position:0% +in some more detail on those optional + + + align:start position:0% +in some more detail on those optional +lecture notes then the theoretical + + align:start position:0% +lecture notes then the theoretical + + + align:start position:0% +lecture notes then the theoretical +models seem to predict that you should + + align:start position:0% +models seem to predict that you should + + + align:start position:0% +models seem to predict that you should +get more and more energy per volume as + + align:start position:0% +get more and more energy per volume as + + + align:start position:0% +get more and more energy per volume as +you raise the frequency and it should + + align:start position:0% +you raise the frequency and it should + + + align:start position:0% +you raise the frequency and it should +grow without bound it should never stop + + align:start position:0% +grow without bound it should never stop + + + align:start position:0% +grow without bound it should never stop +so it seemed like everything should be + + align:start position:0% +so it seemed like everything should be + + + align:start position:0% +so it seemed like everything should be +glowing infinitely all the time we + + align:start position:0% +glowing infinitely all the time we + + + align:start position:0% +glowing infinitely all the time we +clearly don't see that + + align:start position:0% +clearly don't see that + + + align:start position:0% +clearly don't see that +that argument came from kind of two + + align:start position:0% +that argument came from kind of two + + + align:start position:0% +that argument came from kind of two +different pieces again I go through that + + align:start position:0% +different pieces again I go through that + + + align:start position:0% +different pieces again I go through that +in a bit more detail in the notes but + + align:start position:0% +in a bit more detail in the notes but + + + align:start position:0% +in a bit more detail in the notes but +the high level summary is that according + + align:start position:0% +the high level summary is that according + + + align:start position:0% +the high level summary is that according +to to work by people like Maxwell and + + align:start position:0% +to to work by people like Maxwell and + + + align:start position:0% +to to work by people like Maxwell and +boltzmann very well established by by + + align:start position:0% +boltzmann very well established by by + + + align:start position:0% +boltzmann very well established by by +the time a plonk began to worry about + + align:start position:0% +the time a plonk began to worry about + + + align:start position:0% +the time a plonk began to worry about +this stuff in thermal equilibrium very + + align:start position:0% +this stuff in thermal equilibrium very + + + align:start position:0% +this stuff in thermal equilibrium very +generally it had been argued each degree + + align:start position:0% +generally it had been argued each degree + + + align:start position:0% +generally it had been argued each degree +of Freedom each way that these um either + + align:start position:0% +of Freedom each way that these um either + + + align:start position:0% +of Freedom each way that these um either +either uh light waves or little bits of + + align:start position:0% +either uh light waves or little bits of + + + align:start position:0% +either uh light waves or little bits of +matter in that block body each of these + + align:start position:0% +matter in that block body each of these + + + align:start position:0% +matter in that block body each of these +things should should share a kind of + + align:start position:0% +things should should share a kind of + + + align:start position:0% +things should should share a kind of +average + + align:start position:0% +average + + + align:start position:0% +average +um energy + + align:start position:0% +um energy + + + align:start position:0% +um energy +proportional to the temperature to which + + align:start position:0% +proportional to the temperature to which + + + align:start position:0% +proportional to the temperature to which +the object have been heated and with the + + align:start position:0% +the object have been heated and with the + + + align:start position:0% +the object have been heated and with the +proportionality known as a constant + + align:start position:0% +proportionality known as a constant + + + align:start position:0% +proportionality known as a constant +known as K We Now call that Boltzmann's + + align:start position:0% +known as K We Now call that Boltzmann's + + + align:start position:0% +known as K We Now call that Boltzmann's +constant this was known as the + + align:start position:0% +constant this was known as the + + + align:start position:0% +constant this was known as the +equipartition theorem that each way in + + align:start position:0% +equipartition theorem that each way in + + + align:start position:0% +equipartition theorem that each way in +which a system could kind of Wiggle or + + align:start position:0% +which a system could kind of Wiggle or + + + align:start position:0% +which a system could kind of Wiggle or +move these so-called degree of Freedom + + align:start position:0% +move these so-called degree of Freedom + + + align:start position:0% +move these so-called degree of Freedom +should be uh should have an equal + + align:start position:0% +should be uh should have an equal + + + align:start position:0% +should be uh should have an equal +average energy that's step one step two + + align:start position:0% +average energy that's step one step two + + + align:start position:0% +average energy that's step one step two +using Maxwell's treatment of light of + + align:start position:0% +using Maxwell's treatment of light of + + + align:start position:0% +using Maxwell's treatment of light of +electromagnetic radiation + + align:start position:0% +electromagnetic radiation + + + align:start position:0% +electromagnetic radiation +you you the argument was that this um + + align:start position:0% +you you the argument was that this um + + + align:start position:0% +you you the argument was that this um +the number of radiation modes degrees of + + align:start position:0% +the number of radiation modes degrees of + + + align:start position:0% +the number of radiation modes degrees of +freedom per unit volume per frequency + + align:start position:0% +freedom per unit volume per frequency + + + align:start position:0% +freedom per unit volume per frequency +should go like new squared combine those + + align:start position:0% +should go like new squared combine those + + + align:start position:0% +should go like new squared combine those +together you get this expectation that + + align:start position:0% +together you get this expectation that + + + align:start position:0% +together you get this expectation that +that the spectral energy density U + + align:start position:0% +that the spectral energy density U + + + align:start position:0% +that the spectral energy density U +should grow quadratically grow as a + + align:start position:0% +should grow quadratically grow as a + + + align:start position:0% +should grow quadratically grow as a +square of the frequency without bath it + + align:start position:0% +square of the frequency without bath it + + + align:start position:0% +square of the frequency without bath it +should rise about linear so everything + + align:start position:0% +should rise about linear so everything + + + align:start position:0% +should rise about linear so everything +should be glowing all the time giving + + align:start position:0% +should be glowing all the time giving + + + align:start position:0% +should be glowing all the time giving +off infinite energy that clearly is not + + align:start position:0% +off infinite energy that clearly is not + + + align:start position:0% +off infinite energy that clearly is not +what we see + + align:start position:0% +what we see + + + align:start position:0% +what we see +so clock as I say had special access to + + align:start position:0% +so clock as I say had special access to + + + align:start position:0% +so clock as I say had special access to +these to his colleagues doing these + + align:start position:0% +these to his colleagues doing these + + + align:start position:0% +these to his colleagues doing these +experiments sort of in real time he knew + + align:start position:0% +experiments sort of in real time he knew + + + align:start position:0% +experiments sort of in real time he knew +better better than anyone that the real + + align:start position:0% +better better than anyone that the real + + + align:start position:0% +better better than anyone that the real +curves looked nothing like this this art + + align:start position:0% +curves looked nothing like this this art + + + align:start position:0% +curves looked nothing like this this art +this sort of uh constantly growing curve + + align:start position:0% +this sort of uh constantly growing curve + + + align:start position:0% +this sort of uh constantly growing curve +of the ultraviolet catastrophe + + align:start position:0% +of the ultraviolet catastrophe + + + align:start position:0% +of the ultraviolet catastrophe +everyone knew that these curves must + + align:start position:0% +everyone knew that these curves must + + + align:start position:0% +everyone knew that these curves must +begin to fall with increasing frequency + + align:start position:0% +begin to fall with increasing frequency + + + align:start position:0% +begin to fall with increasing frequency +Planck had an extra Insight or extra + + align:start position:0% +Planck had an extra Insight or extra + + + align:start position:0% +Planck had an extra Insight or extra +information not just that the curb + + align:start position:0% +information not just that the curb + + + align:start position:0% +information not just that the curb +should fall but how it should fall the + + align:start position:0% +should fall but how it should fall the + + + align:start position:0% +should fall but how it should fall the +the actual shape of that curve like this + + align:start position:0% +the actual shape of that curve like this + + + align:start position:0% +the actual shape of that curve like this +part here basically this part here in in + + align:start position:0% +part here basically this part here in in + + + align:start position:0% +part here basically this part here in in +wavelength how should that curve Begin + + align:start position:0% +wavelength how should that curve Begin + + + align:start position:0% +wavelength how should that curve Begin +to Fall as you go to shorter and shorter + + align:start position:0% +to Fall as you go to shorter and shorter + + + align:start position:0% +to Fall as you go to shorter and shorter +wavelengths or higher and higher + + align:start position:0% +wavelengths or higher and higher + + + align:start position:0% +wavelengths or higher and higher +frequencies so he began to Tinker and in + + align:start position:0% +frequencies so he began to Tinker and in + + + align:start position:0% +frequencies so he began to Tinker and in +fact very famously on a particular date + + align:start position:0% +fact very famously on a particular date + + + align:start position:0% +fact very famously on a particular date +December 14 1900 he presented a paper to + + align:start position:0% +December 14 1900 he presented a paper to + + + align:start position:0% +December 14 1900 he presented a paper to +his colleagues at a physics society + + align:start position:0% +his colleagues at a physics society + + + align:start position:0% +his colleagues at a physics society +meeting in which he presented this form + + align:start position:0% +meeting in which he presented this form + + + align:start position:0% +meeting in which he presented this form +for uh for the this spectral energy + + align:start position:0% +for uh for the this spectral energy + + + align:start position:0% +for uh for the this spectral energy +density but it should rise not as new + + align:start position:0% +density but it should rise not as new + + + align:start position:0% +density but it should rise not as new +squared like that ultraviolet + + align:start position:0% +squared like that ultraviolet + + + align:start position:0% +squared like that ultraviolet +catastrophe but it actually have this a + + align:start position:0% +catastrophe but it actually have this a + + + align:start position:0% +catastrophe but it actually have this a +bit more complicated structure + + align:start position:0% +bit more complicated structure + + + align:start position:0% +bit more complicated structure +and this was really interesting because + + align:start position:0% +and this was really interesting because + + + align:start position:0% +and this was really interesting because +it would match very well that both the + + align:start position:0% +it would match very well that both the + + + align:start position:0% +it would match very well that both the +arguments from people like boltzmann uh + + align:start position:0% +arguments from people like boltzmann uh + + + align:start position:0% +arguments from people like boltzmann uh +and Maxwell in in one region of the + + align:start position:0% +and Maxwell in in one region of the + + + align:start position:0% +and Maxwell in in one region of the +graph for sorry for very uh low + + align:start position:0% +graph for sorry for very uh low + + + align:start position:0% +graph for sorry for very uh low +frequency very long wavelengths so over + + align:start position:0% +frequency very long wavelengths so over + + + align:start position:0% +frequency very long wavelengths so over +here on this real data over here on this + + align:start position:0% +here on this real data over here on this + + + align:start position:0% +here on this real data over here on this +plot it converges to the to the original + + align:start position:0% +plot it converges to the to the original + + + align:start position:0% +plot it converges to the to the original +expectation but then it kind of has this + + align:start position:0% +expectation but then it kind of has this + + + align:start position:0% +expectation but then it kind of has this +natural turnaround and so that at higher + + align:start position:0% +natural turnaround and so that at higher + + + align:start position:0% +natural turnaround and so that at higher +frequencies at shorter wavelengths in + + align:start position:0% +frequencies at shorter wavelengths in + + + align:start position:0% +frequencies at shorter wavelengths in +fact you should have this gently + + align:start position:0% +fact you should have this gently + + + align:start position:0% +fact you should have this gently +decaying tail this exponential tail both + + align:start position:0% +decaying tail this exponential tail both + + + align:start position:0% +decaying tail this exponential tail both +of those features are contained in this + + align:start position:0% +of those features are contained in this + + + align:start position:0% +of those features are contained in this +one expression as you take the + + align:start position:0% +one expression as you take the + + + align:start position:0% +one expression as you take the +appropriate limits he also had to + + align:start position:0% +appropriate limits he also had to + + + align:start position:0% +appropriate limits he also had to +introduce this new constant H which had + + align:start position:0% +introduce this new constant H which had + + + align:start position:0% +introduce this new constant H which had +not been introduced before we now call + + align:start position:0% +not been introduced before we now call + + + align:start position:0% +not been introduced before we now call +it Planck's constant + + align:start position:0% +it Planck's constant + + + align:start position:0% +it Planck's constant +now as at least in part to make his + + align:start position:0% +now as at least in part to make his + + + align:start position:0% +now as at least in part to make his +units match the quantity KT has units of + + align:start position:0% +units match the quantity KT has units of + + + align:start position:0% +units match the quantity KT has units of +energy T is a temperature K boatswain + + align:start position:0% +energy T is a temperature K boatswain + + + align:start position:0% +energy T is a temperature K boatswain +constant together form units of energy + + align:start position:0% +constant together form units of energy + + + align:start position:0% +constant together form units of energy +new here is the frequency one over time + + align:start position:0% +new here is the frequency one over time + + + align:start position:0% +new here is the frequency one over time +like one over seconds hurts so that + + align:start position:0% +like one over seconds hurts so that + + + align:start position:0% +like one over seconds hurts so that +doesn't have the same units as energy so + + align:start position:0% +doesn't have the same units as energy so + + + align:start position:0% +doesn't have the same units as energy so +we added this this extra kind of fudge + + align:start position:0% +we added this this extra kind of fudge + + + align:start position:0% +we added this this extra kind of fudge +called H to make sure the units would + + align:start position:0% +called H to make sure the units would + + + align:start position:0% +called H to make sure the units would +match and also to try to begin to match + + align:start position:0% +match and also to try to begin to match + + + align:start position:0% +match and also to try to begin to match +the actual quantitative shape of the + + align:start position:0% +the actual quantitative shape of the + + + align:start position:0% +the actual quantitative shape of the +data from his comics + + align:start position:0% +data from his comics + + + align:start position:0% +data from his comics +so in this treatment at the very closing + + align:start position:0% +so in this treatment at the very closing + + + align:start position:0% +so in this treatment at the very closing +days of the year 1900 plonk introduced + + align:start position:0% +days of the year 1900 plonk introduced + + + align:start position:0% +days of the year 1900 plonk introduced +not only a new form for the spectral + + align:start position:0% +not only a new form for the spectral + + + align:start position:0% +not only a new form for the spectral +energy density again there's more on + + align:start position:0% +energy density again there's more on + + + align:start position:0% +energy density again there's more on +that on on that in those lecture notes + + align:start position:0% +that on on that in those lecture notes + + + align:start position:0% +that on on that in those lecture notes +he also introduces this new Universal + + align:start position:0% +he also introduces this new Universal + + + align:start position:0% +he also introduces this new Universal +constant We Now call Planck's cost it's + + align:start position:0% +constant We Now call Planck's cost it's + + + align:start position:0% +constant We Now call Planck's cost it's +this number H just a constant it really + + align:start position:0% +this number H just a constant it really + + + align:start position:0% +this number H just a constant it really +sets the scale for these departures + + align:start position:0% +sets the scale for these departures + + + align:start position:0% +sets the scale for these departures +based on the calculations we would make + + align:start position:0% +based on the calculations we would make + + + align:start position:0% +based on the calculations we would make +from Newton's physics or even maximums + + align:start position:0% +from Newton's physics or even maximums + + + align:start position:0% +from Newton's physics or even maximums +equations how much do these newer ideas + + align:start position:0% +equations how much do these newer ideas + + + align:start position:0% +equations how much do these newer ideas +of what becomes known as quantum theory + + align:start position:0% +of what becomes known as quantum theory + + + align:start position:0% +of what becomes known as quantum theory +how much should they depart or when + + align:start position:0% +how much should they depart or when + + + align:start position:0% +how much should they depart or when +should we expect a deviation + + align:start position:0% +should we expect a deviation + + + align:start position:0% +should we expect a deviation +and plonk's value that he inferred from + + align:start position:0% +and plonk's value that he inferred from + + + align:start position:0% +and plonk's value that he inferred from +his colleagues measurements at the PTR + + align:start position:0% +his colleagues measurements at the PTR + + + align:start position:0% +his colleagues measurements at the PTR +was actually remarkably close to the + + align:start position:0% +was actually remarkably close to the + + + align:start position:0% +was actually remarkably close to the +modern value we use to this day here's a + + align:start position:0% +modern value we use to this day here's a + + + align:start position:0% +modern value we use to this day here's a +modern value Planck's inferred value is + + align:start position:0% +modern value Planck's inferred value is + + + align:start position:0% +modern value Planck's inferred value is +pretty close + + align:start position:0% +pretty close + + + align:start position:0% +pretty close +in units that are familiar for kind of + + align:start position:0% +in units that are familiar for kind of + + + align:start position:0% +in units that are familiar for kind of +macroscopic everyday human activities + + align:start position:0% +macroscopic everyday human activities + + + align:start position:0% +macroscopic everyday human activities +the so-called CGS system when we measure + + align:start position:0% +the so-called CGS system when we measure + + + align:start position:0% +the so-called CGS system when we measure +distances in centimeters masses and + + align:start position:0% +distances in centimeters masses and + + + align:start position:0% +distances in centimeters masses and +grams and times and seconds that's where + + align:start position:0% +grams and times and seconds that's where + + + align:start position:0% +grams and times and seconds that's where +the CGS comes from energy as you may + + align:start position:0% +the CGS comes from energy as you may + + + align:start position:0% +the CGS comes from energy as you may +recall is given this unit of an ER which + + align:start position:0% +recall is given this unit of an ER which + + + align:start position:0% +recall is given this unit of an ER which +really is just one gram uh centimeter + + align:start position:0% +really is just one gram uh centimeter + + + align:start position:0% +really is just one gram uh centimeter +squared per second squared in those CGS + + align:start position:0% +squared per second squared in those CGS + + + align:start position:0% +squared per second squared in those CGS +units H is incredibly small it's + + align:start position:0% +units H is incredibly small it's + + + align:start position:0% +units H is incredibly small it's +exponentially tiny in those natural + + align:start position:0% +exponentially tiny in those natural + + + align:start position:0% +exponentially tiny in those natural +units for kind of human scaled affairs + + align:start position:0% +units for kind of human scaled affairs + + + align:start position:0% +units for kind of human scaled affairs +so H is small if we consider for example + + align:start position:0% +so H is small if we consider for example + + + align:start position:0% +so H is small if we consider for example +drop a single grape + + align:start position:0% +drop a single grape + + + align:start position:0% +drop a single grape +from a height of five centimeters + + align:start position:0% +from a height of five centimeters + + + align:start position:0% +from a height of five centimeters +roughly two inches and then ask what's + + align:start position:0% +roughly two inches and then ask what's + + + align:start position:0% +roughly two inches and then ask what's +the kinetic energy that grape will + + align:start position:0% +the kinetic energy that grape will + + + align:start position:0% +the kinetic energy that grape will +acquire over that very short Journey let + + align:start position:0% +acquire over that very short Journey let + + + align:start position:0% +acquire over that very short Journey let +the grape fall from rest a total of five + + align:start position:0% +the grape fall from rest a total of five + + + align:start position:0% +the grape fall from rest a total of five +centimeters multiply its acquired + + align:start position:0% +centimeters multiply its acquired + + + align:start position:0% +centimeters multiply its acquired +kinetic energy times the duration during + + align:start position:0% +kinetic energy times the duration during + + + align:start position:0% +kinetic energy times the duration during +which it was falling roughly a second or + + align:start position:0% +which it was falling roughly a second or + + + align:start position:0% +which it was falling roughly a second or +so + + align:start position:0% +so + + + align:start position:0% +so +and yet an enormous amount of energy + + align:start position:0% +and yet an enormous amount of energy + + + align:start position:0% +and yet an enormous amount of energy +times time if we measure in this Planck + + align:start position:0% +times time if we measure in this Planck + + + align:start position:0% +times time if we measure in this Planck +uh in in these Planck units so just that + + align:start position:0% +uh in in these Planck units so just that + + + align:start position:0% +uh in in these Planck units so just that +tiny little grape falling for about one + + align:start position:0% +tiny little grape falling for about one + + + align:start position:0% +tiny little grape falling for about one +second from roughly two inches high has + + align:start position:0% +second from roughly two inches high has + + + align:start position:0% +second from roughly two inches high has +10 to the 28 of plant units of energy + + align:start position:0% +10 to the 28 of plant units of energy + + + align:start position:0% +10 to the 28 of plant units of energy +time some of you might know that this + + align:start position:0% +time some of you might know that this + + + align:start position:0% +time some of you might know that this +this particular combination of units and + + align:start position:0% +this particular combination of units and + + + align:start position:0% +this particular combination of units and +energy times a Time unit Eric's seconds + + align:start position:0% +energy times a Time unit Eric's seconds + + + align:start position:0% +energy times a Time unit Eric's seconds +is also the units in which we measure + + align:start position:0% +is also the units in which we measure + + + align:start position:0% +is also the units in which we measure +things like angular momentum what's the + + align:start position:0% +things like angular momentum what's the + + + align:start position:0% +things like angular momentum what's the +momentum of the sort of circular motion + + align:start position:0% +momentum of the sort of circular motion + + + align:start position:0% +momentum of the sort of circular motion +so again let's take a kind of household + + align:start position:0% +so again let's take a kind of household + + + align:start position:0% +so again let's take a kind of household +example instead of dropping a grape + + align:start position:0% +example instead of dropping a grape + + + align:start position:0% +example instead of dropping a grape +imagine some really annoying house fly + + align:start position:0% +imagine some really annoying house fly + + + align:start position:0% +imagine some really annoying house fly +they're kind of buzzing around your head + + align:start position:0% +they're kind of buzzing around your head + + + align:start position:0% +they're kind of buzzing around your head +at some radius of you know a couple + + align:start position:0% +at some radius of you know a couple + + + align:start position:0% +at some radius of you know a couple +centimeters from your head super + + align:start position:0% +centimeters from your head super + + + align:start position:0% +centimeters from your head super +annoying what's the angular momentum + + align:start position:0% +annoying what's the angular momentum + + + align:start position:0% +annoying what's the angular momentum +with that tiny little fly as it just + + align:start position:0% +with that tiny little fly as it just + + + align:start position:0% +with that tiny little fly as it just +buzzes kind of lazily around your head + + align:start position:0% +buzzes kind of lazily around your head + + + align:start position:0% +buzzes kind of lazily around your head +again it will have angular momentum + + align:start position:0% +again it will have angular momentum + + + align:start position:0% +again it will have angular momentum +exponentially large if we were to + + align:start position:0% +exponentially large if we were to + + + align:start position:0% +exponentially large if we were to +measure it in units of these of Planck's + + align:start position:0% +measure it in units of these of Planck's + + + align:start position:0% +measure it in units of these of Planck's +constant again around 10 to the 28th + + align:start position:0% +constant again around 10 to the 28th + + + align:start position:0% +constant again around 10 to the 28th +okay on which we expect to find strange + + align:start position:0% +okay on which we expect to find strange + + + align:start position:0% +okay on which we expect to find strange +Quantum features in our everyday life + + align:start position:0% +Quantum features in our everyday life + + + align:start position:0% +Quantum features in our everyday life +grapes house flies Automobiles and so on + + align:start position:0% +grapes house flies Automobiles and so on + + + align:start position:0% +grapes house flies Automobiles and so on +and yet plug could only make sense of + + align:start position:0% +and yet plug could only make sense of + + + align:start position:0% +and yet plug could only make sense of +that pgr data if you introduced this new + + align:start position:0% +that pgr data if you introduced this new + + + align:start position:0% +that pgr data if you introduced this new +scale this new constant very different + + align:start position:0% +scale this new constant very different + + + align:start position:0% +scale this new constant very different +from Human Experience and yet not zero + + align:start position:0% +from Human Experience and yet not zero + + + align:start position:0% +from Human Experience and yet not zero +some finite value even if it's small in + + align:start position:0% +some finite value even if it's small in + + + align:start position:0% +some finite value even if it's small in +our human terms + + align:start position:0% +our human terms + + + align:start position:0% +our human terms +now one of the readings you had for + + align:start position:0% +now one of the readings you had for + + + align:start position:0% +now one of the readings you had for +today was by the historian Thomas Kuhn + + align:start position:0% +today was by the historian Thomas Kuhn + + + align:start position:0% +today was by the historian Thomas Kuhn +Kuhn wrote a really fascinating book + + align:start position:0% +Kuhn wrote a really fascinating book + + + align:start position:0% +Kuhn wrote a really fascinating book +here's here's the book cover and the + + align:start position:0% +here's here's the book cover and the + + + align:start position:0% +here's here's the book cover and the +kind of uh article version that you had + + align:start position:0% +kind of uh article version that you had + + + align:start position:0% +kind of uh article version that you had +draws on the same body of work and I + + align:start position:0% +draws on the same body of work and I + + + align:start position:0% +draws on the same body of work and I +find this super fascinating so we know + + align:start position:0% +find this super fascinating so we know + + + align:start position:0% +find this super fascinating so we know +that Planck published that formula the + + align:start position:0% +that Planck published that formula the + + + align:start position:0% +that Planck published that formula the +one that I showed before uh where the + + align:start position:0% +one that I showed before uh where the + + + align:start position:0% +one that I showed before uh where the +frequencies you go like Nu cubed over e + + align:start position:0% +frequencies you go like Nu cubed over e + + + align:start position:0% +frequencies you go like Nu cubed over e +to the H Nu over KT minus one this we + + align:start position:0% +to the H Nu over KT minus one this we + + + align:start position:0% +to the H Nu over KT minus one this we +now call that the Planck Spectrum we use + + align:start position:0% +now call that the Planck Spectrum we use + + + align:start position:0% +now call that the Planck Spectrum we use +it all the time we know exactly when he + + align:start position:0% +it all the time we know exactly when he + + + align:start position:0% +it all the time we know exactly when he +wrote it down and published it but we + + align:start position:0% +wrote it down and published it but we + + + align:start position:0% +wrote it down and published it but we +still don't really know or still + + align:start position:0% +still don't really know or still + + + align:start position:0% +still don't really know or still +controversial is what did Planck think + + align:start position:0% +controversial is what did Planck think + + + align:start position:0% +controversial is what did Planck think +he was doing when he wrote down that + + align:start position:0% +he was doing when he wrote down that + + + align:start position:0% +he was doing when he wrote down that +expression how did Planck interpret his + + align:start position:0% +expression how did Planck interpret his + + + align:start position:0% +expression how did Planck interpret his +own equation here we are yet again + + align:start position:0% +own equation here we are yet again + + + align:start position:0% +own equation here we are yet again +thrown into this really I think + + align:start position:0% +thrown into this really I think + + + align:start position:0% +thrown into this really I think +delicious question of how a single + + align:start position:0% +delicious question of how a single + + + align:start position:0% +delicious question of how a single +equation could be subject to many often + + align:start position:0% +equation could be subject to many often + + + align:start position:0% +equation could be subject to many often +competing interpretations and was + + align:start position:0% +competing interpretations and was + + + align:start position:0% +competing interpretations and was +among the first to try to argue + + align:start position:0% +among the first to try to argue + + + align:start position:0% +among the first to try to argue +in particular that plugs own roots to + + align:start position:0% +in particular that plugs own roots to + + + align:start position:0% +in particular that plugs own roots to +that now very famous equation looked + + align:start position:0% +that now very famous equation looked + + + align:start position:0% +that now very famous equation looked +nothing like what we how we interpreted + + align:start position:0% +nothing like what we how we interpreted + + + align:start position:0% +nothing like what we how we interpreted +the result so when we derive plug's + + align:start position:0% +the result so when we derive plug's + + + align:start position:0% +the result so when we derive plug's +expression like for example in my own + + align:start position:0% +expression like for example in my own + + + align:start position:0% +expression like for example in my own +notes or any textbook you might you + + align:start position:0% +notes or any textbook you might you + + + align:start position:0% +notes or any textbook you might you +might look it up in a modern textbook we + + align:start position:0% +might look it up in a modern textbook we + + + align:start position:0% +might look it up in a modern textbook we +say we get Planck's result for that form + + align:start position:0% +say we get Planck's result for that form + + + align:start position:0% +say we get Planck's result for that form +for this spectral energy density by + + align:start position:0% +for this spectral energy density by + + + align:start position:0% +for this spectral energy density by +making a new conceptual leap by + + align:start position:0% +making a new conceptual leap by + + + align:start position:0% +making a new conceptual leap by +requiring that the energy exchange + + align:start position:0% +requiring that the energy exchange + + + align:start position:0% +requiring that the energy exchange +between matter and radiation can't take + + align:start position:0% +between matter and radiation can't take + + + align:start position:0% +between matter and radiation can't take +any old value it can't be 6 or 6.001 or + + align:start position:0% +any old value it can't be 6 or 6.001 or + + + align:start position:0% +any old value it can't be 6 or 6.001 or +6.002 in appropriate units but how to + + align:start position:0% +6.002 in appropriate units but how to + + + align:start position:0% +6.002 in appropriate units but how to +come chunked has to come quantized in + + align:start position:0% +come chunked has to come quantized in + + + align:start position:0% +come chunked has to come quantized in +these units of a particular size flux + + align:start position:0% +these units of a particular size flux + + + align:start position:0% +these units of a particular size flux +constant H times the frequency of the + + align:start position:0% +constant H times the frequency of the + + + align:start position:0% +constant H times the frequency of the +light involved rather than than treating + + align:start position:0% +light involved rather than than treating + + + align:start position:0% +light involved rather than than treating +the sort of energy exchange between + + align:start position:0% +the sort of energy exchange between + + + align:start position:0% +the sort of energy exchange between +matter and radiation as continuous the + + align:start position:0% +matter and radiation as continuous the + + + align:start position:0% +matter and radiation as continuous the +way we would if we were describing light + + align:start position:0% +way we would if we were describing light + + + align:start position:0% +way we would if we were describing light +for example as maxwellian waves it + + align:start position:0% +for example as maxwellian waves it + + + align:start position:0% +for example as maxwellian waves it +shouldn't matter what the frequency is + + align:start position:0% +shouldn't matter what the frequency is + + + align:start position:0% +shouldn't matter what the frequency is +of that wave we know how to calculate + + align:start position:0% +of that wave we know how to calculate + + + align:start position:0% +of that wave we know how to calculate +the energy associated with any process + + align:start position:0% +the energy associated with any process + + + align:start position:0% +the energy associated with any process +and there should be no limit no chunking + + align:start position:0% +and there should be no limit no chunking + + + align:start position:0% +and there should be no limit no chunking +or quantization + + align:start position:0% +or quantization + + + align:start position:0% +or quantization +so Chrome was asking very very directly + + align:start position:0% +so Chrome was asking very very directly + + + align:start position:0% +so Chrome was asking very very directly +did Mark's Planck think that's what he + + align:start position:0% +did Mark's Planck think that's what he + + + align:start position:0% +did Mark's Planck think that's what he +was doing in around 1900 when he + + align:start position:0% +was doing in around 1900 when he + + + align:start position:0% +was doing in around 1900 when he +introduced what we now call Planck's + + align:start position:0% +introduced what we now call Planck's + + + align:start position:0% +introduced what we now call Planck's +formula and so just to give the + + align:start position:0% +formula and so just to give the + + + align:start position:0% +formula and so just to give the +highlight of kuhn's article it's a + + align:start position:0% +highlight of kuhn's article it's a + + + align:start position:0% +highlight of kuhn's article it's a +complicated article if it was confusing + + align:start position:0% +complicated article if it was confusing + + + align:start position:0% +complicated article if it was confusing +that's okay I want to talk through what + + align:start position:0% +that's okay I want to talk through what + + + align:start position:0% +that's okay I want to talk through what +I consider the kind of headline news the + + align:start position:0% +I consider the kind of headline news the + + + align:start position:0% +I consider the kind of headline news the +main takeaways from Coons architecture + + align:start position:0% +main takeaways from Coons architecture + + + align:start position:0% +main takeaways from Coons architecture +it's a very complicated writing here's + + align:start position:0% +it's a very complicated writing here's + + + align:start position:0% +it's a very complicated writing here's +what I consider the biggest Revelations + + align:start position:0% +what I consider the biggest Revelations + + + align:start position:0% +what I consider the biggest Revelations +so argues that in Plants original + + align:start position:0% +so argues that in Plants original + + + align:start position:0% +so argues that in Plants original +derivation this now very famous + + align:start position:0% +derivation this now very famous + + + align:start position:0% +derivation this now very famous +canonical formula Planck fixed the total + + align:start position:0% +canonical formula Planck fixed the total + + + align:start position:0% +canonical formula Planck fixed the total +energy of the system all the Imagine + + align:start position:0% +energy of the system all the Imagine + + + align:start position:0% +energy of the system all the Imagine +little kind of resonators or kind of + + align:start position:0% +little kind of resonators or kind of + + + align:start position:0% +little kind of resonators or kind of +Make-Believe molecules in that black + + align:start position:0% +Make-Believe molecules in that black + + + align:start position:0% +Make-Believe molecules in that black +body he fixed the total energy of that + + align:start position:0% +body he fixed the total energy of that + + + align:start position:0% +body he fixed the total energy of that +system to be an integer number of these + + align:start position:0% +system to be an integer number of these + + + align:start position:0% +system to be an integer number of these +units H new but he according to + + align:start position:0% +units H new but he according to + + + align:start position:0% +units H new but he according to +plant did not fix each actual resonator + + align:start position:0% +plant did not fix each actual resonator + + + align:start position:0% +plant did not fix each actual resonator +each each degree of freedom of that + + align:start position:0% +each each degree of freedom of that + + + align:start position:0% +each each degree of freedom of that +system to separately be have uh this + + align:start position:0% +system to separately be have uh this + + + align:start position:0% +system to separately be have uh this +value H Nu so that plaque was fixing the + + align:start position:0% +value H Nu so that plaque was fixing the + + + align:start position:0% +value H Nu so that plaque was fixing the +total energy for convenience as a kind + + align:start position:0% +total energy for convenience as a kind + + + align:start position:0% +total energy for convenience as a kind +of accounting trick not fixing the unit + + align:start position:0% +of accounting trick not fixing the unit + + + align:start position:0% +of accounting trick not fixing the unit +of each moving part + + align:start position:0% +of each moving part + + + align:start position:0% +of each moving part +whereas today again as I go through in + + align:start position:0% +whereas today again as I go through in + + + align:start position:0% +whereas today again as I go through in +some details in those notes we derive + + align:start position:0% +some details in those notes we derive + + + align:start position:0% +some details in those notes we derive +plant's result by fixing the allowable + + align:start position:0% +plant's result by fixing the allowable + + + align:start position:0% +plant's result by fixing the allowable +energy of each individual part each sort + + align:start position:0% +energy of each individual part each sort + + + align:start position:0% +energy of each individual part each sort +of e sub I so to speak okay in plug's + + align:start position:0% +of e sub I so to speak okay in plug's + + + align:start position:0% +of e sub I so to speak okay in plug's +description as reconstruction uh + + align:start position:0% +description as reconstruction uh + + + align:start position:0% +description as reconstruction uh +the energies for each of these + + align:start position:0% +the energies for each of these + + + align:start position:0% +the energies for each of these +subsystems each kind of moving part + + align:start position:0% +subsystems each kind of moving part + + + align:start position:0% +subsystems each kind of moving part +according to plug's original derivation + + align:start position:0% +according to plug's original derivation + + + align:start position:0% +according to plug's original derivation +was actually assumed to fall within some + + align:start position:0% +was actually assumed to fall within some + + + align:start position:0% +was actually assumed to fall within some +continuous range between e and e plus + + align:start position:0% +continuous range between e and e plus + + + align:start position:0% +continuous range between e and e plus +Delta e not fixed kind of you know + + align:start position:0% +Delta e not fixed kind of you know + + + align:start position:0% +Delta e not fixed kind of you know +snapping in place in these quantized + + align:start position:0% +snapping in place in these quantized + + + align:start position:0% +snapping in place in these quantized +units + + align:start position:0% +units + + + align:start position:0% +units +so goes on it's a very complicated + + align:start position:0% +so goes on it's a very complicated + + + align:start position:0% +so goes on it's a very complicated +argument the book is even more + + align:start position:0% +argument the book is even more + + + align:start position:0% +argument the book is even more +complicated + + align:start position:0% +complicated + + + align:start position:0% +complicated +but according to Coon's analysis plant + + align:start position:0% +but according to Coon's analysis plant + + + align:start position:0% +but according to Coon's analysis plant +uses bins of size we might call it uses + + align:start position:0% +uses bins of size we might call it uses + + + align:start position:0% +uses bins of size we might call it uses +the Greek letter Epsilon bins of size H + + align:start position:0% +the Greek letter Epsilon bins of size H + + + align:start position:0% +the Greek letter Epsilon bins of size H +Nu for his accounting but again only to + + align:start position:0% +Nu for his accounting but again only to + + + align:start position:0% +Nu for his accounting but again only to +say how many of these sort of resonators + + align:start position:0% +say how many of these sort of resonators + + + align:start position:0% +say how many of these sort of resonators +or oscillators again roughly speaking + + align:start position:0% +or oscillators again roughly speaking + + + align:start position:0% +or oscillators again roughly speaking +moving Parts how many of them had + + align:start position:0% +moving Parts how many of them had + + + align:start position:0% +moving Parts how many of them had +energies within you know within zero and + + align:start position:0% +energies within you know within zero and + + + align:start position:0% +energies within you know within zero and +Epsilon within one unit between one and + + align:start position:0% +Epsilon within one unit between one and + + + align:start position:0% +Epsilon within one unit between one and +two units not that they had to have + + align:start position:0% +two units not that they had to have + + + align:start position:0% +two units not that they had to have +exactly one or two units the way we'd + + align:start position:0% +exactly one or two units the way we'd + + + align:start position:0% +exactly one or two units the way we'd +say today + + align:start position:0% +say today + + + align:start position:0% +say today +moreover a goes on again he does + + align:start position:0% +moreover a goes on again he does + + + align:start position:0% +moreover a goes on again he does +this even in more detail in this longer + + align:start position:0% +this even in more detail in this longer + + + align:start position:0% +this even in more detail in this longer +book years later six years later flock + + align:start position:0% +book years later six years later flock + + + align:start position:0% +book years later six years later flock +was giving lectures at the University + + align:start position:0% +was giving lectures at the University + + + align:start position:0% +was giving lectures at the University +about this topic and he still spoke in + + align:start position:0% +about this topic and he still spoke in + + + align:start position:0% +about this topic and he still spoke in +his lecture notes of a kind of + + align:start position:0% +his lecture notes of a kind of + + + align:start position:0% +his lecture notes of a kind of +continuous rather than quantized energy + + align:start position:0% +continuous rather than quantized energy + + + align:start position:0% +continuous rather than quantized energy +exchange it wasn't just a kind of + + align:start position:0% +exchange it wasn't just a kind of + + + align:start position:0% +exchange it wasn't just a kind of +momentary lapse in December of 1900 + + align:start position:0% +momentary lapse in December of 1900 + + + align:start position:0% +momentary lapse in December of 1900 +Argus Thomas it was years and years + + align:start position:0% +Argus Thomas it was years and years + + + align:start position:0% +Argus Thomas it was years and years +during which Planck thought about his + + align:start position:0% +during which Planck thought about his + + + align:start position:0% +during which Planck thought about his +own equation quite differently than the + + align:start position:0% +own equation quite differently than the + + + align:start position:0% +own equation quite differently than the +way we would today even though the + + align:start position:0% +way we would today even though the + + + align:start position:0% +way we would today even though the +equation itself hasn't changed now + + align:start position:0% +equation itself hasn't changed now + + + align:start position:0% +equation itself hasn't changed now +that's Coon's argument he has lots of + + align:start position:0% +that's Coon's argument he has lots of + + + align:start position:0% +that's Coon's argument he has lots of +evidence that I found very interesting + + align:start position:0% +evidence that I found very interesting + + + align:start position:0% +evidence that I found very interesting +it's also really complicated there's a + + align:start position:0% +it's also really complicated there's a + + + align:start position:0% +it's also really complicated there's a +fascinating much more recent article uh + + align:start position:0% +fascinating much more recent article uh + + + align:start position:0% +fascinating much more recent article uh +by the physicist and historian Michael + + align:start position:0% +by the physicist and historian Michael + + + align:start position:0% +by the physicist and historian Michael +nauenberg you can look up uh that + + align:start position:0% +nauenberg you can look up uh that + + + align:start position:0% +nauenberg you can look up uh that +actually draws sort of the opposite + + align:start position:0% +actually draws sort of the opposite + + + align:start position:0% +actually draws sort of the opposite +conclusion that plug had a much more + + align:start position:0% +conclusion that plug had a much more + + + align:start position:0% +conclusion that plug had a much more +similar notion of what we have today + + align:start position:0% +similar notion of what we have today + + + align:start position:0% +similar notion of what we have today +even as always 1900 it's really + + align:start position:0% +even as always 1900 it's really + + + align:start position:0% +even as always 1900 it's really +complicated so I don't know who of these + + align:start position:0% +complicated so I don't know who of these + + + align:start position:0% +complicated so I don't know who of these +analysts is right what I do know is it + + align:start position:0% +analysts is right what I do know is it + + + align:start position:0% +analysts is right what I do know is it +was really really not clear even to + + align:start position:0% +was really really not clear even to + + + align:start position:0% +was really really not clear even to +plant's own contemporaries what exactly + + align:start position:0% +plant's own contemporaries what exactly + + + align:start position:0% +plant's own contemporaries what exactly +to make of this new formula + + align:start position:0% +to make of this new formula + + + align:start position:0% +to make of this new formula +and plonk himself was not shy about that + + align:start position:0% +and plonk himself was not shy about that + + + align:start position:0% +and plonk himself was not shy about that +he wrote to a colleague decades later 31 + + align:start position:0% +he wrote to a colleague decades later 31 + + + align:start position:0% +he wrote to a colleague decades later 31 +years after deriving his now famous + + align:start position:0% +years after deriving his now famous + + + align:start position:0% +years after deriving his now famous +equation he wrote what I did back in + + align:start position:0% +equation he wrote what I did back in + + + align:start position:0% +equation he wrote what I did back in +1900 can be described as simply an act + + align:start position:0% +1900 can be described as simply an act + + + align:start position:0% +1900 can be described as simply an act +of desperation he was trying to match + + align:start position:0% +of desperation he was trying to match + + + align:start position:0% +of desperation he was trying to match +the updated data from the PTR he knew + + align:start position:0% +the updated data from the PTR he knew + + + align:start position:0% +the updated data from the PTR he knew +that curve couldn't just keep Rising + + align:start position:0% +that curve couldn't just keep Rising + + + align:start position:0% +that curve couldn't just keep Rising +forever he was desperate and choosing + + align:start position:0% +forever he was desperate and choosing + + + align:start position:0% +forever he was desperate and choosing +these bins of fixed quantized size plan + + align:start position:0% +these bins of fixed quantized size plan + + + align:start position:0% +these bins of fixed quantized size plan +continued was purely a formal assumption + + align:start position:0% +continued was purely a formal assumption + + + align:start position:0% +continued was purely a formal assumption +and I really did not give it much + + align:start position:0% +and I really did not give it much + + + align:start position:0% +and I really did not give it much +thought which is interesting + + align:start position:0% +thought which is interesting + + + align:start position:0% +thought which is interesting +so let me pause there that's what I want + + align:start position:0% +so let me pause there that's what I want + + + align:start position:0% +so let me pause there that's what I want +to share about Planck and the black body + + align:start position:0% +to share about Planck and the black body + + + align:start position:0% +to share about Planck and the black body +Spectrum any questions about that + + align:start position:0% + + + + align:start position:0% + +uh Jade asked a good question in the + + align:start position:0% +uh Jade asked a good question in the + + + align:start position:0% +uh Jade asked a good question in the +chat how do they measure the spectral + + align:start position:0% +chat how do they measure the spectral + + + align:start position:0% +chat how do they measure the spectral +energy density very good so the short + + align:start position:0% +energy density very good so the short + + + align:start position:0% +energy density very good so the short +answer is this is the kind of thing that + + align:start position:0% +answer is this is the kind of thing that + + + align:start position:0% +answer is this is the kind of thing that +the that the experimentalists at the pgr + + align:start position:0% +the that the experimentalists at the pgr + + + align:start position:0% +the that the experimentalists at the pgr +were very very good at so they could use + + align:start position:0% +were very very good at so they could use + + + align:start position:0% +were very very good at so they could use +basically things like + + align:start position:0% +basically things like + + + align:start position:0% +basically things like +um a diffraction gratings and they might + + align:start position:0% +um a diffraction gratings and they might + + + align:start position:0% +um a diffraction gratings and they might +have even had access to to fine prisons + + align:start position:0% +have even had access to to fine prisons + + + align:start position:0% +have even had access to to fine prisons +to to measure very specific energy + + align:start position:0% +to to measure very specific energy + + + align:start position:0% +to to measure very specific energy +outputs in very specific um wavelength + + align:start position:0% +outputs in very specific um wavelength + + + align:start position:0% +outputs in very specific um wavelength +bids so that that's the kind of thing + + align:start position:0% +bids so that that's the kind of thing + + + align:start position:0% +bids so that that's the kind of thing +they were getting very good at I think + + align:start position:0% +they were getting very good at I think + + + align:start position:0% +they were getting very good at I think +they did mostly use diffraction rate so + + align:start position:0% +they did mostly use diffraction rate so + + + align:start position:0% +they did mostly use diffraction rate so +I'm not positive so they could they had + + align:start position:0% +I'm not positive so they could they had + + + align:start position:0% +I'm not positive so they could they had +a cavity a kind of evacuated chamber + + align:start position:0% +a cavity a kind of evacuated chamber + + + align:start position:0% +a cavity a kind of evacuated chamber +they could heat up kind of in an oven + + align:start position:0% +they could heat up kind of in an oven + + + align:start position:0% +they could heat up kind of in an oven +with a little hole in the side so mostly + + align:start position:0% +with a little hole in the side so mostly + + + align:start position:0% +with a little hole in the side so mostly +had this empty space that would heat up + + align:start position:0% +had this empty space that would heat up + + + align:start position:0% +had this empty space that would heat up +and they would let a little a cavity let + + align:start position:0% +and they would let a little a cavity let + + + align:start position:0% +and they would let a little a cavity let +a little bit of this light sneak out a + + align:start position:0% +a little bit of this light sneak out a + + + align:start position:0% +a little bit of this light sneak out a +little window + + align:start position:0% +little window + + + align:start position:0% +little window +uh and that's what was taking the place + + align:start position:0% +uh and that's what was taking the place + + + align:start position:0% +uh and that's what was taking the place +of this black body so no light was + + align:start position:0% +of this black body so no light was + + + align:start position:0% +of this black body so no light was +coming in onto that box it was sealed up + + align:start position:0% +coming in onto that box it was sealed up + + + align:start position:0% +coming in onto that box it was sealed up +like a kind of metal trap cavity a + + align:start position:0% +like a kind of metal trap cavity a + + + align:start position:0% +like a kind of metal trap cavity a +little light escapes to a little + + align:start position:0% +little light escapes to a little + + + align:start position:0% +little light escapes to a little +porthole and so what you should be + + align:start position:0% +porthole and so what you should be + + + align:start position:0% +porthole and so what you should be +measuring is only the light due to this + + align:start position:0% +measuring is only the light due to this + + + align:start position:0% +measuring is only the light due to this +kind of thermal radiation because + + align:start position:0% +kind of thermal radiation because + + + align:start position:0% +kind of thermal radiation because +nothing is reflecting on that stuff + + align:start position:0% +nothing is reflecting on that stuff + + + align:start position:0% +nothing is reflecting on that stuff +that's how they made the black body in + + align:start position:0% +that's how they made the black body in + + + align:start position:0% +that's how they made the black body in +in real life in the actual experience + + align:start position:0% +in real life in the actual experience + + + align:start position:0% +in real life in the actual experience +then they could subject that light that + + align:start position:0% +then they could subject that light that + + + align:start position:0% +then they could subject that light that +came out to very fine measurements by + + align:start position:0% +came out to very fine measurements by + + + align:start position:0% +came out to very fine measurements by +splitting up into into its colors with + + align:start position:0% +splitting up into into its colors with + + + align:start position:0% +splitting up into into its colors with +with things like diffraction gratings or + + align:start position:0% +with things like diffraction gratings or + + + align:start position:0% +with things like diffraction gratings or +prisms + + align:start position:0% +prisms + + + align:start position:0% +prisms +and then and then measure let's see they + + align:start position:0% +and then and then measure let's see they + + + align:start position:0% +and then and then measure let's see they +must have measured the intensity of the + + align:start position:0% +must have measured the intensity of the + + + align:start position:0% +must have measured the intensity of the +brightness they must have had some kind + + align:start position:0% +brightness they must have had some kind + + + align:start position:0% +brightness they must have had some kind +of photo meters and I'm not sure how + + align:start position:0% +of photo meters and I'm not sure how + + + align:start position:0% +of photo meters and I'm not sure how +they did that we can look it up but they + + align:start position:0% +they did that we can look it up but they + + + align:start position:0% +they did that we can look it up but they +were good at measuring very finely + + align:start position:0% +were good at measuring very finely + + + align:start position:0% +were good at measuring very finely +detailed um uh wavelengths in fact + + align:start position:0% +detailed um uh wavelengths in fact + + + align:start position:0% +detailed um uh wavelengths in fact +they're getting better in the core over + + align:start position:0% +they're getting better in the core over + + + align:start position:0% +they're getting better in the core over +the 1890s in various parts of the + + align:start position:0% +the 1890s in various parts of the + + + align:start position:0% +the 1890s in various parts of the +spectrum they knew some of the early + + align:start position:0% +spectrum they knew some of the early + + + align:start position:0% +spectrum they knew some of the early +data points early on the ones that + + align:start position:0% +data points early on the ones that + + + align:start position:0% +data points early on the ones that +matched this Rising curve that looks + + align:start position:0% +matched this Rising curve that looks + + + align:start position:0% +matched this Rising curve that looks +like it would lead to this runaway + + align:start position:0% +like it would lead to this runaway + + + align:start position:0% +like it would lead to this runaway +energy this so-called ultraviolet + + align:start position:0% +energy this so-called ultraviolet + + + align:start position:0% +energy this so-called ultraviolet +catastrophe the earliest data were at + + align:start position:0% +catastrophe the earliest data were at + + + align:start position:0% +catastrophe the earliest data were at +low wavelengths uh small frequencies we + + align:start position:0% +low wavelengths uh small frequencies we + + + align:start position:0% +low wavelengths uh small frequencies we +really did go like Nu squared and what + + align:start position:0% +really did go like Nu squared and what + + + align:start position:0% +really did go like Nu squared and what +was most important as everyone knew was + + align:start position:0% +was most important as everyone knew was + + + align:start position:0% +was most important as everyone knew was +to measure the other end of the spectrum + + align:start position:0% +to measure the other end of the spectrum + + + align:start position:0% +to measure the other end of the spectrum +that couldn't keep Rising forever and + + align:start position:0% +that couldn't keep Rising forever and + + + align:start position:0% +that couldn't keep Rising forever and +the PTR researchers like Lumber and + + align:start position:0% +the PTR researchers like Lumber and + + + align:start position:0% +the PTR researchers like Lumber and +Princeton were getting more and more + + align:start position:0% +Princeton were getting more and more + + + align:start position:0% +Princeton were getting more and more +data at the other part of the spectrum + + align:start position:0% +data at the other part of the spectrum + + + align:start position:0% +data at the other part of the spectrum +at shorter wavelengths higher + + align:start position:0% +at shorter wavelengths higher + + + align:start position:0% +at shorter wavelengths higher +frequencies and watching just how that + + align:start position:0% +frequencies and watching just how that + + + align:start position:0% +frequencies and watching just how that +curve began to fall what we now would + + align:start position:0% +curve began to fall what we now would + + + align:start position:0% +curve began to fall what we now would +recognize as this kind of exponential + + align:start position:0% +recognize as this kind of exponential + + + align:start position:0% +recognize as this kind of exponential +tale so they were doing that again with + + align:start position:0% +tale so they were doing that again with + + + align:start position:0% +tale so they were doing that again with +with with more and more precision + + align:start position:0% +with with more and more precision + + + align:start position:0% +with with more and more precision +excellent question Johan asks a very + + align:start position:0% +excellent question Johan asks a very + + + align:start position:0% +excellent question Johan asks a very +good question how to do that with a + + align:start position:0% +good question how to do that with a + + + align:start position:0% +good question how to do that with a +graph and calculator he was no Cambridge + + align:start position:0% +graph and calculator he was no Cambridge + + + align:start position:0% +graph and calculator he was no Cambridge +Wrangler but Planck was a pretty well + + align:start position:0% +Wrangler but Planck was a pretty well + + + align:start position:0% +Wrangler but Planck was a pretty well +trained mathematical physicist it was + + align:start position:0% +trained mathematical physicist it was + + + align:start position:0% +trained mathematical physicist it was +painstack and the real factors is + + align:start position:0% +painstack and the real factors is + + + align:start position:0% +painstack and the real factors is +painstaking and also how did he come up + + align:start position:0% +painstaking and also how did he come up + + + align:start position:0% +painstaking and also how did he come up +with these particular forms or his + + align:start position:0% +with these particular forms or his + + + align:start position:0% +with these particular forms or his +equations you know you can read Thomas + + align:start position:0% +equations you know you can read Thomas + + + align:start position:0% +equations you know you can read Thomas +Coons like 400 page monograph which I + + align:start position:0% +Coons like 400 page monograph which I + + + align:start position:0% +Coons like 400 page monograph which I +have forced rather encouraged some of + + align:start position:0% +have forced rather encouraged some of + + + align:start position:0% +have forced rather encouraged some of +the Tas to do directly uh I would say + + align:start position:0% +the Tas to do directly uh I would say + + + align:start position:0% +the Tas to do directly uh I would say +encouraged uh I reread it every few + + align:start position:0% +encouraged uh I reread it every few + + + align:start position:0% +encouraged uh I reread it every few +years it's really complicated I mean + + align:start position:0% +years it's really complicated I mean + + + align:start position:0% +years it's really complicated I mean +what was plant doing what was doing when + + align:start position:0% +what was plant doing what was doing when + + + align:start position:0% +what was plant doing what was doing when +what did he think he was doing that is + + align:start position:0% +what did he think he was doing that is + + + align:start position:0% +what did he think he was doing that is +really complicated and other really + + align:start position:0% +really complicated and other really + + + align:start position:0% +really complicated and other really +smart dedicated researchers like Michael + + align:start position:0% +smart dedicated researchers like Michael + + + align:start position:0% +smart dedicated researchers like Michael +nalmer come back to some of the same + + align:start position:0% +nalmer come back to some of the same + + + align:start position:0% +nalmer come back to some of the same +materials the same obscure lecture notes + + align:start position:0% +materials the same obscure lecture notes + + + align:start position:0% +materials the same obscure lecture notes +the same Publications he says no look + + align:start position:0% +the same Publications he says no look + + + align:start position:0% +the same Publications he says no look +very carefully the equation 25 B he does + + align:start position:0% +very carefully the equation 25 B he does + + + align:start position:0% +very carefully the equation 25 B he does +something else there it gets really + + align:start position:0% +something else there it gets really + + + align:start position:0% +something else there it gets really +really hard + + align:start position:0% +really hard + + + align:start position:0% +really hard +what is clear as I'll say actually the + + align:start position:0% +what is clear as I'll say actually the + + + align:start position:0% +what is clear as I'll say actually the +next section is that some other of + + align:start position:0% +next section is that some other of + + + align:start position:0% +next section is that some other of +plant's own contemporaries like it's + + align:start position:0% +plant's own contemporaries like it's + + + align:start position:0% +plant's own contemporaries like it's +still a very young Albert Einstein + + align:start position:0% +still a very young Albert Einstein + + + align:start position:0% +still a very young Albert Einstein +Einstein was convinced that plug + + align:start position:0% +Einstein was convinced that plug + + + align:start position:0% +Einstein was convinced that plug +actually hadn't gone far enough so it's + + align:start position:0% +actually hadn't gone far enough so it's + + + align:start position:0% +actually hadn't gone far enough so it's +not just historians who debate this the + + align:start position:0% +not just historians who debate this the + + + align:start position:0% +not just historians who debate this the +better part of a century later after + + align:start position:0% +better part of a century later after + + + align:start position:0% +better part of a century later after +plonk even some contemporaries who are + + align:start position:0% +plonk even some contemporaries who are + + + align:start position:0% +plonk even some contemporaries who are +trying to make sense of Planck's on + + align:start position:0% +trying to make sense of Planck's on + + + align:start position:0% +trying to make sense of Planck's on +argument thought that plant's reasoning + + align:start position:0% +argument thought that plant's reasoning + + + align:start position:0% +argument thought that plant's reasoning +was at best muddled and may be different + + align:start position:0% +was at best muddled and may be different + + + align:start position:0% +was at best muddled and may be different +from what they themselves thought about + + align:start position:0% +from what they themselves thought about + + + align:start position:0% +from what they themselves thought about +and that's why I like that letter that + + align:start position:0% +and that's why I like that letter that + + + align:start position:0% +and that's why I like that letter that +plot wrote in the early 30s saying yeah + + align:start position:0% +plot wrote in the early 30s saying yeah + + + align:start position:0% +plot wrote in the early 30s saying yeah +like I didn't know what I was doing is + + align:start position:0% +like I didn't know what I was doing is + + + align:start position:0% +like I didn't know what I was doing is +essentially how I read that quote I was + + align:start position:0% +essentially how I read that quote I was + + + align:start position:0% +essentially how I read that quote I was +desperate + + align:start position:0% +desperate + + + align:start position:0% +desperate +so I think that's really interesting any + + align:start position:0% +so I think that's really interesting any + + + align:start position:0% +so I think that's really interesting any +other questions on the black body + + align:start position:0% +other questions on the black body + + + align:start position:0% +other questions on the black body +Specter or plugs formula + + align:start position:0% +Specter or plugs formula + + + align:start position:0% +Specter or plugs formula +if not let's go on and see what Einstein + + align:start position:0% +if not let's go on and see what Einstein + + + align:start position:0% +if not let's go on and see what Einstein +begins to do with that in that same uh + + align:start position:0% +begins to do with that in that same uh + + + align:start position:0% +begins to do with that in that same uh +famous year of 1905. so let's go to that + + align:start position:0% +famous year of 1905. so let's go to that + + + align:start position:0% +famous year of 1905. so let's go to that +next part so now we're going to talk + + align:start position:0% +next part so now we're going to talk + + + align:start position:0% +next part so now we're going to talk +about uh Einstein and what becomes known + + align:start position:0% +about uh Einstein and what becomes known + + + align:start position:0% +about uh Einstein and what becomes known +as the photoelectric effect + + align:start position:0% + + + + align:start position:0% + +it turns out + + align:start position:0% +it turns out + + + align:start position:0% +it turns out +plug was was concerned about the + + align:start position:0% +plug was was concerned about the + + + align:start position:0% +plug was was concerned about the +interaction between light and matter he + + align:start position:0% +interaction between light and matter he + + + align:start position:0% +interaction between light and matter he +wasn't even in his own writings talking + + align:start position:0% +wasn't even in his own writings talking + + + align:start position:0% +wasn't even in his own writings talking +about the the propagation of light on + + align:start position:0% +about the the propagation of light on + + + align:start position:0% +about the the propagation of light on +his own for which he just took right off + + align:start position:0% +his own for which he just took right off + + + align:start position:0% +his own for which he just took right off +the shelf Maxwell's by then quite + + align:start position:0% +the shelf Maxwell's by then quite + + + align:start position:0% +the shelf Maxwell's by then quite +standard treatment the light is clearly + + align:start position:0% +standard treatment the light is clearly + + + align:start position:0% +standard treatment the light is clearly +a continuous wave spread out through + + align:start position:0% +a continuous wave spread out through + + + align:start position:0% +a continuous wave spread out through +space + + align:start position:0% +space + + + align:start position:0% +space +and so in 1905 just a few years later + + align:start position:0% +and so in 1905 just a few years later + + + align:start position:0% +and so in 1905 just a few years later +young Albert Einstein as we know still + + align:start position:0% +young Albert Einstein as we know still + + + align:start position:0% +young Albert Einstein as we know still +Pat mcclurk third class + + align:start position:0% +Pat mcclurk third class + + + align:start position:0% +Pat mcclurk third class +began to think about the nature of light + + align:start position:0% +began to think about the nature of light + + + align:start position:0% +began to think about the nature of light +on its own even when it's not + + align:start position:0% +on its own even when it's not + + + align:start position:0% +on its own even when it's not +necessarily interacting with matter this + + align:start position:0% +necessarily interacting with matter this + + + align:start position:0% +necessarily interacting with matter this +was actually the first of these four + + align:start position:0% +was actually the first of these four + + + align:start position:0% +was actually the first of these four +kind of amazing or surprising papers + + align:start position:0% +kind of amazing or surprising papers + + + align:start position:0% +kind of amazing or surprising papers +that Einstein wound up submitting to the + + align:start position:0% +that Einstein wound up submitting to the + + + align:start position:0% +that Einstein wound up submitting to the +island of Physique in that year in 1905. + + align:start position:0% +island of Physique in that year in 1905. + + + align:start position:0% +island of Physique in that year in 1905. +the first of them that he sent into the + + align:start position:0% +the first of them that he sent into the + + + align:start position:0% +the first of them that he sent into the +journal in back in March of that year + + align:start position:0% +journal in back in March of that year + + + align:start position:0% +journal in back in March of that year +was the one on what he calls light + + align:start position:0% +was the one on what he calls light + + + align:start position:0% +was the one on what he calls light +quanta + + align:start position:0% +quanta + + + align:start position:0% +quanta +now Einstein was thinking not only about + + align:start position:0% +now Einstein was thinking not only about + + + align:start position:0% +now Einstein was thinking not only about +Planck's work he was to think about that + + align:start position:0% +Planck's work he was to think about that + + + align:start position:0% +Planck's work he was to think about that +they had other recent experiments or + + align:start position:0% +they had other recent experiments or + + + align:start position:0% +they had other recent experiments or +descriptions of light in mind as well + + align:start position:0% +descriptions of light in mind as well + + + align:start position:0% +descriptions of light in mind as well +one of which the one that that he was + + align:start position:0% +one of which the one that that he was + + + align:start position:0% +one of which the one that that he was +even more kind of focused on + + align:start position:0% +even more kind of focused on + + + align:start position:0% +even more kind of focused on +was a series of again kind of puzzling + + align:start position:0% +was a series of again kind of puzzling + + + align:start position:0% +was a series of again kind of puzzling +experimental results that had just been + + align:start position:0% +experimental results that had just been + + + align:start position:0% +experimental results that had just been +coming out uh Through The Years up + + align:start position:0% +coming out uh Through The Years up + + + align:start position:0% +coming out uh Through The Years up +through 1902 by the German researcher + + align:start position:0% +through 1902 by the German researcher + + + align:start position:0% +through 1902 by the German researcher +Philip Leonard if that name sounds + + align:start position:0% +Philip Leonard if that name sounds + + + align:start position:0% +Philip Leonard if that name sounds +familiar it's because we just talked + + align:start position:0% +familiar it's because we just talked + + + align:start position:0% +familiar it's because we just talked +briefly about Leonard in the previous + + align:start position:0% +briefly about Leonard in the previous + + + align:start position:0% +briefly about Leonard in the previous +lecture Leonard went on years later to + + align:start position:0% +lecture Leonard went on years later to + + + align:start position:0% +lecture Leonard went on years later to +become one of the kind of front uh front + + align:start position:0% +become one of the kind of front uh front + + + align:start position:0% +become one of the kind of front uh front +men so to speak of that Deutsche + + align:start position:0% +men so to speak of that Deutsche + + + align:start position:0% +men so to speak of that Deutsche +physique movement what are the people + + align:start position:0% +physique movement what are the people + + + align:start position:0% +physique movement what are the people +who would begin denouncing Einstein and + + align:start position:0% +who would begin denouncing Einstein and + + + align:start position:0% +who would begin denouncing Einstein and +relativity starting as early as 1920. + + align:start position:0% +relativity starting as early as 1920. + + + align:start position:0% +relativity starting as early as 1920. +Leonard was conducting these experiments + + align:start position:0% +Leonard was conducting these experiments + + + align:start position:0% +Leonard was conducting these experiments +at what became known as the + + align:start position:0% +at what became known as the + + + align:start position:0% +at what became known as the +photoelectric effect in the early years + + align:start position:0% +photoelectric effect in the early years + + + align:start position:0% +photoelectric effect in the early years +of the 20th century he his the sort of + + align:start position:0% +of the 20th century he his the sort of + + + align:start position:0% +of the 20th century he his the sort of +sharpest the clearest experimental + + align:start position:0% +sharpest the clearest experimental + + + align:start position:0% +sharpest the clearest experimental +results were published in 1902 he was + + align:start position:0% +results were published in 1902 he was + + + align:start position:0% +results were published in 1902 he was +recognized very early on for that work + + align:start position:0% +recognized very early on for that work + + + align:start position:0% +recognized very early on for that work +he won the Nobel Prize in 1905. the very + + align:start position:0% +he won the Nobel Prize in 1905. the very + + + align:start position:0% +he won the Nobel Prize in 1905. the very +year that Einstein + + align:start position:0% +year that Einstein + + + align:start position:0% +year that Einstein +begins trying to come up with a + + align:start position:0% +begins trying to come up with a + + + align:start position:0% +begins trying to come up with a +theoretical explanation uh for these uh + + align:start position:0% +theoretical explanation uh for these uh + + + align:start position:0% +theoretical explanation uh for these uh +experimental results so what were what + + align:start position:0% +experimental results so what were what + + + align:start position:0% +experimental results so what were what +were Leonard's results here again in + + align:start position:0% +were Leonard's results here again in + + + align:start position:0% +were Leonard's results here again in +kind of cartoon form is the are the + + align:start position:0% +kind of cartoon form is the are the + + + align:start position:0% +kind of cartoon form is the are the +fundamentals of the experiments that + + align:start position:0% +fundamentals of the experiments that + + + align:start position:0% +fundamentals of the experiments that +Leonard uh was was pursuing in fact + + align:start position:0% +Leonard uh was was pursuing in fact + + + align:start position:0% +Leonard uh was was pursuing in fact +others around the world were doing + + align:start position:0% +others around the world were doing + + + align:start position:0% +others around the world were doing +similar things Leonard had in some sense + + align:start position:0% +similar things Leonard had in some sense + + + align:start position:0% +similar things Leonard had in some sense +the kind of cleanest data that forced + + align:start position:0% +the kind of cleanest data that forced + + + align:start position:0% +the kind of cleanest data that forced +the kind of most sharp Showdown with how + + align:start position:0% +the kind of most sharp Showdown with how + + + align:start position:0% +the kind of most sharp Showdown with how +to make sense of these results others + + align:start position:0% +to make sense of these results others + + + align:start position:0% +to make sense of these results others +are doing similar things he had a very + + align:start position:0% +are doing similar things he had a very + + + align:start position:0% +are doing similar things he had a very +simple kind of apparatus so these two + + align:start position:0% +simple kind of apparatus so these two + + + align:start position:0% +simple kind of apparatus so these two +blue + + align:start position:0% +blue + + + align:start position:0% +blue +um pieces here represent metallic + + align:start position:0% +um pieces here represent metallic + + + align:start position:0% +um pieces here represent metallic +conducting plates + + align:start position:0% +conducting plates + + + align:start position:0% +conducting plates +and across the Lennard could apply a + + align:start position:0% +and across the Lennard could apply a + + + align:start position:0% +and across the Lennard could apply a +voltage of a of an amount he could vary + + align:start position:0% +voltage of a of an amount he could vary + + + align:start position:0% +voltage of a of an amount he could vary +he had a tunable voltage between his + + align:start position:0% +he had a tunable voltage between his + + + align:start position:0% +he had a tunable voltage between his +conducting plates he would then direct + + align:start position:0% +conducting plates he would then direct + + + align:start position:0% +conducting plates he would then direct +an ultraviolet light source sorry an + + align:start position:0% +an ultraviolet light source sorry an + + + align:start position:0% +an ultraviolet light source sorry an +ultraviolet light source onto one of + + align:start position:0% +ultraviolet light source onto one of + + + align:start position:0% +ultraviolet light source onto one of +those plates so he has some source of + + align:start position:0% +those plates so he has some source of + + + align:start position:0% +those plates so he has some source of +ultraviolet light shining it on one of + + align:start position:0% +ultraviolet light shining it on one of + + + align:start position:0% +ultraviolet light shining it on one of +those flights + + align:start position:0% +those flights + + + align:start position:0% +those flights +and under certain conditions the light + + align:start position:0% +and under certain conditions the light + + + align:start position:0% +and under certain conditions the light +source when it irradiates that plate + + align:start position:0% +source when it irradiates that plate + + + align:start position:0% +source when it irradiates that plate +would eject would kick out some + + align:start position:0% +would eject would kick out some + + + align:start position:0% +would eject would kick out some +electrons + + align:start position:0% +electrons + + + align:start position:0% +electrons +the electrons are then traveled toward + + align:start position:0% +the electrons are then traveled toward + + + align:start position:0% +the electrons are then traveled toward +the other conducting plate completing a + + align:start position:0% +the other conducting plate completing a + + + align:start position:0% +the other conducting plate completing a +circuit so when the light kicked out + + align:start position:0% +circuit so when the light kicked out + + + align:start position:0% +circuit so when the light kicked out +electrons ejected electrons from this + + align:start position:0% +electrons ejected electrons from this + + + align:start position:0% +electrons ejected electrons from this +um so-called cathode + + align:start position:0% +um so-called cathode + + + align:start position:0% +um so-called cathode +for that metal conducting plate you + + align:start position:0% +for that metal conducting plate you + + + align:start position:0% +for that metal conducting plate you +could complete a circuit because + + align:start position:0% +could complete a circuit because + + + align:start position:0% +could complete a circuit because +electrons would now travel through the + + align:start position:0% +electrons would now travel through the + + + align:start position:0% +electrons would now travel through the +intervening space and hit this plate and + + align:start position:0% +intervening space and hit this plate and + + + align:start position:0% +intervening space and hit this plate and +you'd know you had electric current + + align:start position:0% +you'd know you had electric current + + + align:start position:0% +you'd know you had electric current +flowing because he hooked up an ammeter + + align:start position:0% +flowing because he hooked up an ammeter + + + align:start position:0% +flowing because he hooked up an ammeter +a measure of electric current so he knew + + align:start position:0% +a measure of electric current so he knew + + + align:start position:0% +a measure of electric current so he knew +he had current flowing you know + + align:start position:0% +he had current flowing you know + + + align:start position:0% +he had current flowing you know +electrons have been kicked out of the + + align:start position:0% +electrons have been kicked out of the + + + align:start position:0% +electrons have been kicked out of the +metal when the ammeter measured an + + align:start position:0% +metal when the ammeter measured an + + + align:start position:0% +metal when the ammeter measured an +electric current and then he could use + + align:start position:0% +electric current and then he could use + + + align:start position:0% +electric current and then he could use +this tunable voltage it could change the + + align:start position:0% +this tunable voltage it could change the + + + align:start position:0% +this tunable voltage it could change the +amount of voltage applied to basically + + align:start position:0% +amount of voltage applied to basically + + + align:start position:0% +amount of voltage applied to basically +ask how much energy where those + + align:start position:0% +ask how much energy where those + + + align:start position:0% +ask how much energy where those +electrons kicked out with + + align:start position:0% +electrons kicked out with + + + align:start position:0% +electrons kicked out with +by asking how strong a voltage he had to + + align:start position:0% +by asking how strong a voltage he had to + + + align:start position:0% +by asking how strong a voltage he had to +tune up to block their passage so we + + align:start position:0% +tune up to block their passage so we + + + align:start position:0% +tune up to block their passage so we +when he when he um applied basically no + + align:start position:0% +when he when he um applied basically no + + + align:start position:0% +when he when he um applied basically no +voltage the electrons would would come + + align:start position:0% +voltage the electrons would would come + + + align:start position:0% +voltage the electrons would would come +across and play an incomplete circuit so + + align:start position:0% +across and play an incomplete circuit so + + + align:start position:0% +across and play an incomplete circuit so +how much kind of countervailing voltage + + align:start position:0% +how much kind of countervailing voltage + + + align:start position:0% +how much kind of countervailing voltage +with an art have to apply to block their + + align:start position:0% +with an art have to apply to block their + + + align:start position:0% +with an art have to apply to block their +passage a kind of repulsive Electro for + + align:start position:0% +passage a kind of repulsive Electro for + + + align:start position:0% +passage a kind of repulsive Electro for +electric force to basically repel the + + align:start position:0% +electric force to basically repel the + + + align:start position:0% +electric force to basically repel the +electrons away from reaching this far + + align:start position:0% +electrons away from reaching this far + + + align:start position:0% +electrons away from reaching this far +plate so when will the current stop that + + align:start position:0% +plate so when will the current stop that + + + align:start position:0% +plate so when will the current stop that +he knows what's called the stopping + + align:start position:0% +he knows what's called the stopping + + + align:start position:0% +he knows what's called the stopping +voltage and that tells them exactly how + + align:start position:0% +voltage and that tells them exactly how + + + align:start position:0% +voltage and that tells them exactly how +much energy the electrons had + + align:start position:0% +much energy the electrons had + + + align:start position:0% +much energy the electrons had +because he had to counteract that much + + align:start position:0% +because he had to counteract that much + + + align:start position:0% +because he had to counteract that much +energy that much sort of electrostatic + + align:start position:0% +energy that much sort of electrostatic + + + align:start position:0% +energy that much sort of electrostatic +force to to turn off that current so now + + align:start position:0% +force to to turn off that current so now + + + align:start position:0% +force to to turn off that current so now +he can start comparing the stopping + + align:start position:0% +he can start comparing the stopping + + + align:start position:0% +he can start comparing the stopping +voltage which for him is a measure of + + align:start position:0% +voltage which for him is a measure of + + + align:start position:0% +voltage which for him is a measure of +the energy with which these electrons + + align:start position:0% +the energy with which these electrons + + + align:start position:0% +the energy with which these electrons +are ejected so we can compare the energy + + align:start position:0% +are ejected so we can compare the energy + + + align:start position:0% +are ejected so we can compare the energy +of the electrons with the frequency of + + align:start position:0% +of the electrons with the frequency of + + + align:start position:0% +of the electrons with the frequency of +this light source he shines light of + + align:start position:0% +this light source he shines light of + + + align:start position:0% +this light source he shines light of +certain frequencies within the + + align:start position:0% +certain frequencies within the + + + align:start position:0% +certain frequencies within the +ultraviolet range onto this metallic + + align:start position:0% +ultraviolet range onto this metallic + + + align:start position:0% +ultraviolet range onto this metallic +plate and he measures the amount of + + align:start position:0% +plate and he measures the amount of + + + align:start position:0% +plate and he measures the amount of +energy of the ejected electrons and + + align:start position:0% +energy of the ejected electrons and + + + align:start position:0% +energy of the ejected electrons and +again a kind of cleaned up form the data + + align:start position:0% +again a kind of cleaned up form the data + + + align:start position:0% +again a kind of cleaned up form the data +started looking like this they had a + + align:start position:0% +started looking like this they had a + + + align:start position:0% +started looking like this they had a +very specific very striking shape + + align:start position:0% +very specific very striking shape + + + align:start position:0% +very specific very striking shape +so on a plot of the energy of the + + align:start position:0% +so on a plot of the energy of the + + + align:start position:0% +so on a plot of the energy of the +electrode ejected electrons versus the + + align:start position:0% +electrode ejected electrons versus the + + + align:start position:0% +electrode ejected electrons versus the +frequency of the incident light the + + align:start position:0% +frequency of the incident light the + + + align:start position:0% +frequency of the incident light the +energy electrons seem to rise linearly + + align:start position:0% +energy electrons seem to rise linearly + + + align:start position:0% +energy electrons seem to rise linearly +but only above some threshold frequency + + align:start position:0% +but only above some threshold frequency + + + align:start position:0% +but only above some threshold frequency +so as the light was tuned to lower and + + align:start position:0% +so as the light was tuned to lower and + + + align:start position:0% +so as the light was tuned to lower and +lower frequencies the light that's being + + align:start position:0% +lower frequencies the light that's being + + + align:start position:0% +lower frequencies the light that's being +shown from this Source there'd be no + + align:start position:0% +shown from this Source there'd be no + + + align:start position:0% +shown from this Source there'd be no +electrons ejected at all there would be + + align:start position:0% +electrons ejected at all there would be + + + align:start position:0% +electrons ejected at all there would be +zero electrons ejected no energy + + align:start position:0% +zero electrons ejected no energy + + + align:start position:0% +zero electrons ejected no energy +Crossing that Gap after you reach some + + align:start position:0% +Crossing that Gap after you reach some + + + align:start position:0% +Crossing that Gap after you reach some +very specific threshold frequency of the + + align:start position:0% +very specific threshold frequency of the + + + align:start position:0% +very specific threshold frequency of the +light + + align:start position:0% +light + + + align:start position:0% +light +you start kicking electrons out as you + + align:start position:0% +you start kicking electrons out as you + + + align:start position:0% +you start kicking electrons out as you +increase the frequency of that light the + + align:start position:0% +increase the frequency of that light the + + + align:start position:0% +increase the frequency of that light the +energy that those electrons carry Rises + + align:start position:0% +energy that those electrons carry Rises + + + align:start position:0% +energy that those electrons carry Rises +the energy of the electrons seem to rise + + align:start position:0% +the energy of the electrons seem to rise + + + align:start position:0% +the energy of the electrons seem to rise +only with passenger depend only with the + + align:start position:0% +only with passenger depend only with the + + + align:start position:0% +only with passenger depend only with the +frequency of that light not with the + + align:start position:0% +frequency of that light not with the + + + align:start position:0% +frequency of that light not with the +intensity you can make this a brighter + + align:start position:0% +intensity you can make this a brighter + + + align:start position:0% +intensity you can make this a brighter +or less bright light source holding the + + align:start position:0% +or less bright light source holding the + + + align:start position:0% +or less bright light source holding the +frequency fixed and that had no impact + + align:start position:0% +frequency fixed and that had no impact + + + align:start position:0% +frequency fixed and that had no impact +on the stopping voltage on the amount of + + align:start position:0% +on the stopping voltage on the amount of + + + align:start position:0% +on the stopping voltage on the amount of +energy required to stop those electrons + + align:start position:0% +energy required to stop those electrons + + + align:start position:0% +energy required to stop those electrons +from traversing that that Gap seemed + + align:start position:0% +from traversing that that Gap seemed + + + align:start position:0% +from traversing that that Gap seemed +pretty strange why was that so strange + + align:start position:0% +pretty strange why was that so strange + + + align:start position:0% +pretty strange why was that so strange +why is it strange to have a threshold + + align:start position:0% +why is it strange to have a threshold + + + align:start position:0% +why is it strange to have a threshold +frequency and why was it strange to have + + align:start position:0% +frequency and why was it strange to have + + + align:start position:0% +frequency and why was it strange to have +the energy of the electrons independent + + align:start position:0% +the energy of the electrons independent + + + align:start position:0% +the energy of the electrons independent +of the intensity of that light depending + + align:start position:0% +of the intensity of that light depending + + + align:start position:0% +of the intensity of that light depending +only on the frequency of the line well + + align:start position:0% +only on the frequency of the line well + + + align:start position:0% +only on the frequency of the line well +again if one took on Maxwell's by then + + align:start position:0% +again if one took on Maxwell's by then + + + align:start position:0% +again if one took on Maxwell's by then +quite standard description of + + align:start position:0% +quite standard description of + + + align:start position:0% +quite standard description of +electromagnetic waves including in the + + align:start position:0% +electromagnetic waves including in the + + + align:start position:0% +electromagnetic waves including in the +ultraviolet part of the spectrum the + + align:start position:0% +ultraviolet part of the spectrum the + + + align:start position:0% +ultraviolet part of the spectrum the +energy carried by those light waves from + + align:start position:0% +energy carried by those light waves from + + + align:start position:0% +energy carried by those light waves from +from Leonard's device should have been + + align:start position:0% +from Leonard's device should have been + + + align:start position:0% +from Leonard's device should have been +proportional to the waves intensity the + + align:start position:0% +proportional to the waves intensity the + + + align:start position:0% +proportional to the waves intensity the +energy sort of script e here with + + align:start position:0% +energy sort of script e here with + + + align:start position:0% +energy sort of script e here with +proportions to the intensity of the + + align:start position:0% +proportions to the intensity of the + + + align:start position:0% +proportions to the intensity of the +Waves the intensity in turn went by this + + align:start position:0% +Waves the intensity in turn went by this + + + align:start position:0% +Waves the intensity in turn went by this +square of those field strengths the + + align:start position:0% +square of those field strengths the + + + align:start position:0% +square of those field strengths the +electric and magnetic field strengths so + + align:start position:0% +electric and magnetic field strengths so + + + align:start position:0% +electric and magnetic field strengths so +why shouldn't Leonard have been able to + + align:start position:0% +why shouldn't Leonard have been able to + + + align:start position:0% +why shouldn't Leonard have been able to +to get very large amplitude Fields high + + align:start position:0% +to get very large amplitude Fields high + + + align:start position:0% +to get very large amplitude Fields high +intensity fields that happen to have a + + align:start position:0% +intensity fields that happen to have a + + + align:start position:0% +intensity fields that happen to have a +long wavelength that were that were a + + align:start position:0% +long wavelength that were that were a + + + align:start position:0% +long wavelength that were that were a +low frequency that should carry as much + + align:start position:0% +low frequency that should carry as much + + + align:start position:0% +low frequency that should carry as much +energy as a short frequency wave out of + + align:start position:0% +energy as a short frequency wave out of + + + align:start position:0% +energy as a short frequency wave out of +a smaller amplitude meaning why couldn't + + align:start position:0% +a smaller amplitude meaning why couldn't + + + align:start position:0% +a smaller amplitude meaning why couldn't +you tune the intensity up and uh and + + align:start position:0% +you tune the intensity up and uh and + + + align:start position:0% +you tune the intensity up and uh and +still get electrons ejected all the way + + align:start position:0% +still get electrons ejected all the way + + + align:start position:0% +still get electrons ejected all the way +down here + + align:start position:0% +down here + + + align:start position:0% +down here +if light really acted like maxwellian + + align:start position:0% +if light really acted like maxwellian + + + align:start position:0% +if light really acted like maxwellian +waves why should there be any threshold + + align:start position:0% +waves why should there be any threshold + + + align:start position:0% +waves why should there be any threshold +of frequency at all you could always + + align:start position:0% +of frequency at all you could always + + + align:start position:0% +of frequency at all you could always +tune up the intensity of low frequent + + align:start position:0% +tune up the intensity of low frequent + + + align:start position:0% +tune up the intensity of low frequent +lower frequency light was at least the + + align:start position:0% +lower frequency light was at least the + + + align:start position:0% +lower frequency light was at least the +expectation + + align:start position:0% +expectation + + + align:start position:0% +expectation +likewise according to Maxwell's work + + align:start position:0% +likewise according to Maxwell's work + + + align:start position:0% +likewise according to Maxwell's work +turning the argument around once you do + + align:start position:0% +turning the argument around once you do + + + align:start position:0% +turning the argument around once you do +kick electrons out above that threshold + + align:start position:0% +kick electrons out above that threshold + + + align:start position:0% +kick electrons out above that threshold +why should the energy that they carry be + + align:start position:0% +why should the energy that they carry be + + + align:start position:0% +why should the energy that they carry be +independent of what people thought would + + align:start position:0% +independent of what people thought would + + + align:start position:0% +independent of what people thought would +be the energy imparted by the Light the + + align:start position:0% +be the energy imparted by the Light the + + + align:start position:0% +be the energy imparted by the Light the +energy and parted by the light again + + align:start position:0% +energy and parted by the light again + + + align:start position:0% +energy and parted by the light again +should vary like the intensity and yet + + align:start position:0% +should vary like the intensity and yet + + + align:start position:0% +should vary like the intensity and yet +the energy that these electrons get kind + + align:start position:0% +the energy that these electrons get kind + + + align:start position:0% +the energy that these electrons get kind +of kicked out with seem not to depend on + + align:start position:0% +of kicked out with seem not to depend on + + + align:start position:0% +of kicked out with seem not to depend on +the brightness the intensity of the + + align:start position:0% +the brightness the intensity of the + + + align:start position:0% +the brightness the intensity of the +source only on the frequency okay so + + align:start position:0% +source only on the frequency okay so + + + align:start position:0% +source only on the frequency okay so +that was um becoming increasingly clear + + align:start position:0% +that was um becoming increasingly clear + + + align:start position:0% +that was um becoming increasingly clear +experimental data so clear that Leonard + + align:start position:0% +experimental data so clear that Leonard + + + align:start position:0% +experimental data so clear that Leonard +received the prize just a few years + + align:start position:0% +received the prize just a few years + + + align:start position:0% +received the prize just a few years +later the Nobel Prize but it was by no + + align:start position:0% +later the Nobel Prize but it was by no + + + align:start position:0% +later the Nobel Prize but it was by no +means clear how to make sense of that + + align:start position:0% +means clear how to make sense of that + + + align:start position:0% +means clear how to make sense of that +combination of results so Einstein's + + align:start position:0% +combination of results so Einstein's + + + align:start position:0% +combination of results so Einstein's +first paper of this uh remarkable year + + align:start position:0% +first paper of this uh remarkable year + + + align:start position:0% +first paper of this uh remarkable year +of 1905 + + align:start position:0% +of 1905 + + + align:start position:0% +of 1905 +was was trying to tackle this directly + + align:start position:0% +was was trying to tackle this directly + + + align:start position:0% +was was trying to tackle this directly +in fact in a letter to one of his + + align:start position:0% +in fact in a letter to one of his + + + align:start position:0% +in fact in a letter to one of his +friends to from the Olympia Academy his + + align:start position:0% +friends to from the Olympia Academy his + + + align:start position:0% +friends to from the Olympia Academy his +friend uh Conrad had beat here Einstein + + align:start position:0% +friend uh Conrad had beat here Einstein + + + align:start position:0% +friend uh Conrad had beat here Einstein +actually called this his most radical of + + align:start position:0% +actually called this his most radical of + + + align:start position:0% +actually called this his most radical of +all the Patriots he was working on that + + align:start position:0% +all the Patriots he was working on that + + + align:start position:0% +all the Patriots he was working on that +year he thought this was the most + + align:start position:0% +year he thought this was the most + + + align:start position:0% +year he thought this was the most +strange or most unexpected + + align:start position:0% +strange or most unexpected + + + align:start position:0% +strange or most unexpected +more so than relativity more so than all + + align:start position:0% +more so than relativity more so than all + + + align:start position:0% +more so than relativity more so than all +the all there is so what he offers he + + align:start position:0% +the all there is so what he offers he + + + align:start position:0% +the all there is so what he offers he +calls a heuristic explanation you see in + + align:start position:0% +calls a heuristic explanation you see in + + + align:start position:0% +calls a heuristic explanation you see in +the title uh oilistician a heuristic + + align:start position:0% +the title uh oilistician a heuristic + + + align:start position:0% +the title uh oilistician a heuristic +kind of hypothetical or a suggestive + + align:start position:0% +kind of hypothetical or a suggestive + + + align:start position:0% +kind of hypothetical or a suggestive +explanation he's not saying Eureka I + + align:start position:0% +explanation he's not saying Eureka I + + + align:start position:0% +explanation he's not saying Eureka I +found it he's he's being maybe + + align:start position:0% +found it he's he's being maybe + + + align:start position:0% +found it he's he's being maybe +uncharacteristically a bit more kind of + + align:start position:0% +uncharacteristically a bit more kind of + + + align:start position:0% +uncharacteristically a bit more kind of +modest here he says here's one way to + + align:start position:0% +modest here he says here's one way to + + + align:start position:0% +modest here he says here's one way to +think about these results + + align:start position:0% +think about these results + + + align:start position:0% +think about these results +a heuristic idea would be to say uh what + + align:start position:0% +a heuristic idea would be to say uh what + + + align:start position:0% +a heuristic idea would be to say uh what +if light itself were quantized what if + + align:start position:0% +if light itself were quantized what if + + + align:start position:0% +if light itself were quantized what if +light traveled through space not like a + + align:start position:0% +light traveled through space not like a + + + align:start position:0% +light traveled through space not like a +continuous spread out wave like + + align:start position:0% +continuous spread out wave like + + + align:start position:0% +continuous spread out wave like +Maxwell's Theory would suggest but + + align:start position:0% +Maxwell's Theory would suggest but + + + align:start position:0% +Maxwell's Theory would suggest but +instead like a collection of localized + + align:start position:0% +instead like a collection of localized + + + align:start position:0% +instead like a collection of localized +quanta + + align:start position:0% +quanta + + + align:start position:0% +quanta +here's a quotation from this paper in + + align:start position:0% +here's a quotation from this paper in + + + align:start position:0% +here's a quotation from this paper in +1905 in English who translated English + + align:start position:0% +1905 in English who translated English + + + align:start position:0% +1905 in English who translated English +he writes that it seems to me these + + align:start position:0% +he writes that it seems to me these + + + align:start position:0% +he writes that it seems to me these +observations about the production of + + align:start position:0% +observations about the production of + + + align:start position:0% +observations about the production of +cathode rays those ejected electrons off + + align:start position:0% +cathode rays those ejected electrons off + + + align:start position:0% +cathode rays those ejected electrons off +that cathode by ultraviolet light he's + + align:start position:0% +that cathode by ultraviolet light he's + + + align:start position:0% +that cathode by ultraviolet light he's +now talking about Leonard's experiments + + align:start position:0% +now talking about Leonard's experiments + + + align:start position:0% +now talking about Leonard's experiments +it seems like these observations are + + align:start position:0% +it seems like these observations are + + + align:start position:0% +it seems like these observations are +more readily understood if one assumes + + align:start position:0% +more readily understood if one assumes + + + align:start position:0% +more readily understood if one assumes +the energy of light is discontinuously + + align:start position:0% +the energy of light is discontinuously + + + align:start position:0% +the energy of light is discontinuously +distributed in space + + align:start position:0% +distributed in space + + + align:start position:0% +distributed in space +the energy of a light Ray spreading out + + align:start position:0% +the energy of a light Ray spreading out + + + align:start position:0% +the energy of a light Ray spreading out +from a point source is not continuously + + align:start position:0% +from a point source is not continuously + + + align:start position:0% +from a point source is not continuously +distributed over an increasing space + + align:start position:0% +distributed over an increasing space + + + align:start position:0% +distributed over an increasing space +like a wave would be like a Maximilian + + align:start position:0% +like a wave would be like a Maximilian + + + align:start position:0% +like a wave would be like a Maximilian +wave or an ocean wave intent but rather + + align:start position:0% +wave or an ocean wave intent but rather + + + align:start position:0% +wave or an ocean wave intent but rather +consists of a finite number of energy + + align:start position:0% +consists of a finite number of energy + + + align:start position:0% +consists of a finite number of energy +quanta + + align:start position:0% +quanta + + + align:start position:0% +quanta +which are localized at points in space + + align:start position:0% +which are localized at points in space + + + align:start position:0% +which are localized at points in space +which move without dividing they are + + align:start position:0% +which move without dividing they are + + + align:start position:0% +which move without dividing they are +literally can't be further divided they + + align:start position:0% +literally can't be further divided they + + + align:start position:0% +literally can't be further divided they +are quantized and which can only be + + align:start position:0% +are quantized and which can only be + + + align:start position:0% +are quantized and which can only be +produced and absorbed as complete units + + align:start position:0% +produced and absorbed as complete units + + + align:start position:0% +produced and absorbed as complete units +these become known as light quanta as + + align:start position:0% +these become known as light quanta as + + + align:start position:0% +these become known as light quanta as +little particles or corpuscles of light + + align:start position:0% +little particles or corpuscles of light + + + align:start position:0% +little particles or corpuscles of light +rather than what was by then going back + + align:start position:0% +rather than what was by then going back + + + align:start position:0% +rather than what was by then going back +to 1800 let alone the 1860s the taken + + align:start position:0% +to 1800 let alone the 1860s the taken + + + align:start position:0% +to 1800 let alone the 1860s the taken +for granted assumption that light was a + + align:start position:0% +for granted assumption that light was a + + + align:start position:0% +for granted assumption that light was a +wave + + align:start position:0% +wave + + + align:start position:0% +wave +going all the way back to say Thomas + + align:start position:0% +going all the way back to say Thomas + + + align:start position:0% +going all the way back to say Thomas +Young's work or the work of several + + align:start position:0% +Young's work or the work of several + + + align:start position:0% +Young's work or the work of several +French Scholars so Einstein is + + align:start position:0% +French Scholars so Einstein is + + + align:start position:0% +French Scholars so Einstein is +suggesting heuristically he's not saying + + align:start position:0% +suggesting heuristically he's not saying + + + align:start position:0% +suggesting heuristically he's not saying +this must be the case he's saying it's + + align:start position:0% +this must be the case he's saying it's + + + align:start position:0% +this must be the case he's saying it's +suggestive and worse worth considering + + align:start position:0% +suggestive and worse worth considering + + + align:start position:0% +suggestive and worse worth considering +that experiments like Leonard's might + + align:start position:0% +that experiments like Leonard's might + + + align:start position:0% +that experiments like Leonard's might +make sense if we change entirely + + align:start position:0% +make sense if we change entirely + + + align:start position:0% +make sense if we change entirely +everything we know about light + + align:start position:0% +everything we know about light + + + align:start position:0% +everything we know about light +so why would that help let's go back to + + align:start position:0% +so why would that help let's go back to + + + align:start position:0% +so why would that help let's go back to +this kind of cartoon version of + + align:start position:0% +this kind of cartoon version of + + + align:start position:0% +this kind of cartoon version of +Leonard's data Einstein was in fact + + align:start position:0% +Leonard's data Einstein was in fact + + + align:start position:0% +Leonard's data Einstein was in fact +following on the nard's experiments the + + align:start position:0% +following on the nard's experiments the + + + align:start position:0% +following on the nard's experiments the +Publications quite closely much much + + align:start position:0% +Publications quite closely much much + + + align:start position:0% +Publications quite closely much much +more closely than anything like the + + align:start position:0% +more closely than anything like the + + + align:start position:0% +more closely than anything like the +Michael's Immortal experiment he really + + align:start position:0% +Michael's Immortal experiment he really + + + align:start position:0% +Michael's Immortal experiment he really +was looking up Leonard's papers and + + align:start position:0% +was looking up Leonard's papers and + + + align:start position:0% +was looking up Leonard's papers and +looking at the graphs and tables very + + align:start position:0% +looking at the graphs and tables very + + + align:start position:0% +looking at the graphs and tables very +carefully Einstein recognized that it + + align:start position:0% +carefully Einstein recognized that it + + + align:start position:0% +carefully Einstein recognized that it +wasn't only a linear relationship + + align:start position:0% +wasn't only a linear relationship + + + align:start position:0% +wasn't only a linear relationship +between the energy of those ejected + + align:start position:0% +between the energy of those ejected + + + align:start position:0% +between the energy of those ejected +electrons and the frequency of the + + align:start position:0% +electrons and the frequency of the + + + align:start position:0% +electrons and the frequency of the +incident light but the slope in + + align:start position:0% +incident light but the slope in + + + align:start position:0% +incident light but the slope in +particular looked awfully close to this + + align:start position:0% +particular looked awfully close to this + + + align:start position:0% +particular looked awfully close to this +new value that had just been introduced + + align:start position:0% +new value that had just been introduced + + + align:start position:0% +new value that had just been introduced +in a totally different context by MOX + + align:start position:0% +in a totally different context by MOX + + + align:start position:0% +in a totally different context by MOX +plunk the slope of this plot looked very + + align:start position:0% +plunk the slope of this plot looked very + + + align:start position:0% +plunk the slope of this plot looked very +much like Planck's constant H that's + + align:start position:0% +much like Planck's constant H that's + + + align:start position:0% +much like Planck's constant H that's +something that Einstein begins to + + align:start position:0% +something that Einstein begins to + + + align:start position:0% +something that Einstein begins to +recognize by going carefully over these + + align:start position:0% +recognize by going carefully over these + + + align:start position:0% +recognize by going carefully over these +experimental results + + align:start position:0% +experimental results + + + align:start position:0% +experimental results +so that leads Einstein to think in the + + align:start position:0% +so that leads Einstein to think in the + + + align:start position:0% +so that leads Einstein to think in the +following way what if each of these + + align:start position:0% +following way what if each of these + + + align:start position:0% +following way what if each of these +discrete little bundles of light energy + + align:start position:0% +discrete little bundles of light energy + + + align:start position:0% +discrete little bundles of light energy +what if each individual like Quantum + + align:start position:0% +what if each individual like Quantum + + + align:start position:0% +what if each individual like Quantum +carried a fixed amount of energy + + align:start position:0% +carried a fixed amount of energy + + + align:start position:0% +carried a fixed amount of energy +proportional to the frequency of light + + align:start position:0% +proportional to the frequency of light + + + align:start position:0% +proportional to the frequency of light +with the constant of proportionality + + align:start position:0% +with the constant of proportionality + + + align:start position:0% +with the constant of proportionality +being this new constant introduced by + + align:start position:0% +being this new constant introduced by + + + align:start position:0% +being this new constant introduced by +MOX block what if light quanta these + + align:start position:0% +MOX block what if light quanta these + + + align:start position:0% +MOX block what if light quanta these +indivisible pellets of light had to + + align:start position:0% +indivisible pellets of light had to + + + align:start position:0% +indivisible pellets of light had to +carry a fixed quantized amount of energy + + align:start position:0% +carry a fixed quantized amount of energy + + + align:start position:0% +carry a fixed quantized amount of energy +not some continuous range that could + + align:start position:0% +not some continuous range that could + + + align:start position:0% +not some continuous range that could +have been any old value + + align:start position:0% +have been any old value + + + align:start position:0% +have been any old value +if that's the case then you have on this + + align:start position:0% +if that's the case then you have on this + + + align:start position:0% +if that's the case then you have on this +photocathode on this conducting plate in + + align:start position:0% +photocathode on this conducting plate in + + + align:start position:0% +photocathode on this conducting plate in +lennar's experiment you have raining + + align:start position:0% +lennar's experiment you have raining + + + align:start position:0% +lennar's experiment you have raining +down on it pellets and pellets each + + align:start position:0% +down on it pellets and pellets each + + + align:start position:0% +down on it pellets and pellets each +carrying a fixed amount of energy age + + align:start position:0% +carrying a fixed amount of energy age + + + align:start position:0% +carrying a fixed amount of energy age +new + + align:start position:0% +new + + + align:start position:0% +new +so then you can imagine an individual + + align:start position:0% +so then you can imagine an individual + + + align:start position:0% +so then you can imagine an individual +like Quantum not some spread out wave an + + align:start position:0% +like Quantum not some spread out wave an + + + align:start position:0% +like Quantum not some spread out wave an +individual particle basically smacking + + align:start position:0% +individual particle basically smacking + + + align:start position:0% +individual particle basically smacking +into an individual electron now it looks + + align:start position:0% +into an individual electron now it looks + + + align:start position:0% +into an individual electron now it looks +like colliding billiard balls so how + + align:start position:0% +like colliding billiard balls so how + + + align:start position:0% +like colliding billiard balls so how +will the energy of the electron change + + align:start position:0% +will the energy of the electron change + + + align:start position:0% +will the energy of the electron change +after it gets smacked by a discrete + + align:start position:0% +after it gets smacked by a discrete + + + align:start position:0% +after it gets smacked by a discrete +pellet of energy a light Quantum with + + align:start position:0% +pellet of energy a light Quantum with + + + align:start position:0% +pellet of energy a light Quantum with +energy H Nu the electron should acquire + + align:start position:0% +energy H Nu the electron should acquire + + + align:start position:0% +energy H Nu the electron should acquire +a predictable amount of energy it should + + align:start position:0% +a predictable amount of energy it should + + + align:start position:0% +a predictable amount of energy it should +absorb that energy carried by the Light + + align:start position:0% +absorb that energy carried by the Light + + + align:start position:0% +absorb that energy carried by the Light +quantum + + align:start position:0% +quantum + + + align:start position:0% +quantum +and it will and yet there will be some + + align:start position:0% +and it will and yet there will be some + + + align:start position:0% +and it will and yet there will be some +some extra energy kind of holding that + + align:start position:0% +some extra energy kind of holding that + + + align:start position:0% +some extra energy kind of holding that +electron bound to its uh atoms and + + align:start position:0% +electron bound to its uh atoms and + + + align:start position:0% +electron bound to its uh atoms and +molecules in the metal that became known + + align:start position:0% +molecules in the metal that became known + + + align:start position:0% +molecules in the metal that became known +as the work function that's kind of like + + align:start position:0% +as the work function that's kind of like + + + align:start position:0% +as the work function that's kind of like +The Binding energy these aren't free + + align:start position:0% +The Binding energy these aren't free + + + align:start position:0% +The Binding energy these aren't free +electrons in in space these electrons + + align:start position:0% +electrons in in space these electrons + + + align:start position:0% +electrons in in space these electrons +bound to a piece of metal there's some + + align:start position:0% +bound to a piece of metal there's some + + + align:start position:0% +bound to a piece of metal there's some +intermolecular or Atomic forces whatever + + align:start position:0% +intermolecular or Atomic forces whatever + + + align:start position:0% +intermolecular or Atomic forces whatever +they are they might vary by material + + align:start position:0% +they are they might vary by material + + + align:start position:0% +they are they might vary by material +there's some function that was often + + align:start position:0% +there's some function that was often + + + align:start position:0% +there's some function that was often +called uh by the Greek letter Capital + + align:start position:0% +called uh by the Greek letter Capital + + + align:start position:0% +called uh by the Greek letter Capital +Phi again a kind of binding energy + + align:start position:0% +Phi again a kind of binding energy + + + align:start position:0% +Phi again a kind of binding energy +and so the electron won't be kicked out + + align:start position:0% +and so the electron won't be kicked out + + + align:start position:0% +and so the electron won't be kicked out +of that piece of metal unless the energy + + align:start position:0% +of that piece of metal unless the energy + + + align:start position:0% +of that piece of metal unless the energy +it absorbs from that discrete like + + align:start position:0% +it absorbs from that discrete like + + + align:start position:0% +it absorbs from that discrete like +Quantum exceeds that binding energy the + + align:start position:0% +Quantum exceeds that binding energy the + + + align:start position:0% +Quantum exceeds that binding energy the +energy holding it in place has to be + + align:start position:0% +energy holding it in place has to be + + + align:start position:0% +energy holding it in place has to be +overcome or exceeded By the Light by the + + align:start position:0% +overcome or exceeded By the Light by the + + + align:start position:0% +overcome or exceeded By the Light by the +energy transferred by that light quantum + + align:start position:0% +energy transferred by that light quantum + + + align:start position:0% +energy transferred by that light quantum +if that's the case then of course there + + align:start position:0% +if that's the case then of course there + + + align:start position:0% +if that's the case then of course there +should be a threshold frequency only + + align:start position:0% +should be a threshold frequency only + + + align:start position:0% +should be a threshold frequency only +when each individual Quantum of light + + align:start position:0% +when each individual Quantum of light + + + align:start position:0% +when each individual Quantum of light +each little pellet a discrete carrier of + + align:start position:0% +each little pellet a discrete carrier of + + + align:start position:0% +each little pellet a discrete carrier of +energy in that incoming light + + align:start position:0% +energy in that incoming light + + + align:start position:0% +energy in that incoming light +carries enough energy individually to + + align:start position:0% +carries enough energy individually to + + + align:start position:0% +carries enough energy individually to +overcome that binding energy or the work + + align:start position:0% +overcome that binding energy or the work + + + align:start position:0% +overcome that binding energy or the work +function only then would any electrons + + align:start position:0% +function only then would any electrons + + + align:start position:0% +function only then would any electrons +be ejected from that piece of metal + + align:start position:0% +be ejected from that piece of metal + + + align:start position:0% +be ejected from that piece of metal +so the threshold frequency should depend + + align:start position:0% +so the threshold frequency should depend + + + align:start position:0% +so the threshold frequency should depend +on that binding energy that work + + align:start position:0% +on that binding energy that work + + + align:start position:0% +on that binding energy that work +function divided by plot's constant + + align:start position:0% +function divided by plot's constant + + + align:start position:0% +function divided by plot's constant +basically what's the threshold that + + align:start position:0% +basically what's the threshold that + + + align:start position:0% +basically what's the threshold that +would set this energy exactly to zero as + + align:start position:0% +would set this energy exactly to zero as + + + align:start position:0% +would set this energy exactly to zero as +opposed to it having a negative energy + + align:start position:0% +opposed to it having a negative energy + + + align:start position:0% +opposed to it having a negative energy +we should say it's bound in place so you + + align:start position:0% +we should say it's bound in place so you + + + align:start position:0% +we should say it's bound in place so you +just solve for when does the electron + + align:start position:0% +just solve for when does the electron + + + align:start position:0% +just solve for when does the electron +just cross that threshold as energy + + align:start position:0% +just cross that threshold as energy + + + align:start position:0% +just cross that threshold as energy +oh it's when Nu equals Phi over H that + + align:start position:0% +oh it's when Nu equals Phi over H that + + + align:start position:0% +oh it's when Nu equals Phi over H that +would that would give you the threshold + + align:start position:0% +would that would give you the threshold + + + align:start position:0% +would that would give you the threshold +any additional energy any higher energy + + align:start position:0% +any additional energy any higher energy + + + align:start position:0% +any additional energy any higher energy +carried by light quanta as you tune the + + align:start position:0% +carried by light quanta as you tune the + + + align:start position:0% +carried by light quanta as you tune the +frequency the incident light higher and + + align:start position:0% +frequency the incident light higher and + + + align:start position:0% +frequency the incident light higher and +higher each electron will absorb more + + align:start position:0% +higher each electron will absorb more + + + align:start position:0% +higher each electron will absorb more +energy than that threshold and it will + + align:start position:0% +energy than that threshold and it will + + + align:start position:0% +energy than that threshold and it will +continue to grow linearly with slope h + + align:start position:0% +continue to grow linearly with slope h + + + align:start position:0% +continue to grow linearly with slope h +so the idea that Einstein puts together + + align:start position:0% +so the idea that Einstein puts together + + + align:start position:0% +so the idea that Einstein puts together +is heuristic it is suggestive idea in + + align:start position:0% +is heuristic it is suggestive idea in + + + align:start position:0% +is heuristic it is suggestive idea in +this 1905 paper is that the light + + align:start position:0% +this 1905 paper is that the light + + + align:start position:0% +this 1905 paper is that the light +shining on this metal plate is not some + + align:start position:0% +shining on this metal plate is not some + + + align:start position:0% +shining on this metal plate is not some +extended continuous wave kind of lapping + + align:start position:0% +extended continuous wave kind of lapping + + + align:start position:0% +extended continuous wave kind of lapping +up on shore like a Maximilian wave but + + align:start position:0% +up on shore like a Maximilian wave but + + + align:start position:0% +up on shore like a Maximilian wave but +actually a shower of discrete marbles + + align:start position:0% +actually a shower of discrete marbles + + + align:start position:0% +actually a shower of discrete marbles +Each of which could Collide like two + + align:start position:0% +Each of which could Collide like two + + + align:start position:0% +Each of which could Collide like two +body collisions like billiard balls on a + + align:start position:0% +body collisions like billiard balls on a + + + align:start position:0% +body collisions like billiard balls on a +on a billion table or you know on pool + + align:start position:0% +on a billion table or you know on pool + + + align:start position:0% +on a billion table or you know on pool +table they would have two body + + align:start position:0% +table they would have two body + + + align:start position:0% +table they would have two body +collisions Each of which can then impart + + align:start position:0% +collisions Each of which can then impart + + + align:start position:0% +collisions Each of which can then impart +certain energy uh to to their to their + + align:start position:0% +certain energy uh to to their to their + + + align:start position:0% +certain energy uh to to their to their +colliding electrons so I like to think + + align:start position:0% +colliding electrons so I like to think + + + align:start position:0% +colliding electrons so I like to think +of it this way imagine electrons are + + align:start position:0% +of it this way imagine electrons are + + + align:start position:0% +of it this way imagine electrons are +like a bucket full of ping-pong balls so + + align:start position:0% +like a bucket full of ping-pong balls so + + + align:start position:0% +like a bucket full of ping-pong balls so +ordinarily they're Bound in place that's + + align:start position:0% +ordinarily they're Bound in place that's + + + align:start position:0% +ordinarily they're Bound in place that's +like that work function the ping pong + + align:start position:0% +like that work function the ping pong + + + align:start position:0% +like that work function the ping pong +balls aren't free to move any old place + + align:start position:0% +balls aren't free to move any old place + + + align:start position:0% +balls aren't free to move any old place +they're stuck they have a certain kind + + align:start position:0% +they're stuck they have a certain kind + + + align:start position:0% +they're stuck they have a certain kind +of binding energy think of that as like + + align:start position:0% +of binding energy think of that as like + + + align:start position:0% +of binding energy think of that as like +that work function Phi + + align:start position:0% +that work function Phi + + + align:start position:0% +that work function Phi +then you start chucking marbles at it + + align:start position:0% +then you start chucking marbles at it + + + align:start position:0% +then you start chucking marbles at it +you imagine like flinging marbles into + + align:start position:0% +you imagine like flinging marbles into + + + align:start position:0% +you imagine like flinging marbles into +that bucket + + align:start position:0% +that bucket + + + align:start position:0% +that bucket +if the marbles individually carry enough + + align:start position:0% +if the marbles individually carry enough + + + align:start position:0% +if the marbles individually carry enough +energy they're going to collide with + + align:start position:0% +energy they're going to collide with + + + align:start position:0% +energy they're going to collide with +individual ping-pong balls and if + + align:start position:0% +individual ping-pong balls and if + + + align:start position:0% +individual ping-pong balls and if +they're Inc if a marbles incoming energy + + align:start position:0% +they're Inc if a marbles incoming energy + + + align:start position:0% +they're Inc if a marbles incoming energy +is more than this binding energy holding + + align:start position:0% +is more than this binding energy holding + + + align:start position:0% +is more than this binding energy holding +the ping-pong balls in the bucket you'll + + align:start position:0% +the ping-pong balls in the bucket you'll + + + align:start position:0% +the ping-pong balls in the bucket you'll +kick a few out that's the picture that + + align:start position:0% +kick a few out that's the picture that + + + align:start position:0% +kick a few out that's the picture that +Einstein has in mind in that same + + align:start position:0% +Einstein has in mind in that same + + + align:start position:0% +Einstein has in mind in that same +actually quite long article this very + + align:start position:0% +actually quite long article this very + + + align:start position:0% +actually quite long article this very +same article in 1905 Einstein also + + align:start position:0% +same article in 1905 Einstein also + + + align:start position:0% +same article in 1905 Einstein also +revisits plug starvation of the black + + align:start position:0% +revisits plug starvation of the black + + + align:start position:0% +revisits plug starvation of the black +body formula that that function that we + + align:start position:0% +body formula that that function that we + + + align:start position:0% +body formula that that function that we +called the spectral energy density + + align:start position:0% +called the spectral energy density + + + align:start position:0% +called the spectral energy density +little U and he rederives plot's formula + + align:start position:0% +little U and he rederives plot's formula + + + align:start position:0% +little U and he rederives plot's formula +assuming that the radiation being + + align:start position:0% +assuming that the radiation being + + + align:start position:0% +assuming that the radiation being +emitted from that cavity radiation + + align:start position:0% +emitted from that cavity radiation + + + align:start position:0% +emitted from that cavity radiation +could be treated like a gas of these + + align:start position:0% +could be treated like a gas of these + + + align:start position:0% +could be treated like a gas of these +individual particles Each of which has a + + align:start position:0% +individual particles Each of which has a + + + align:start position:0% +individual particles Each of which has a +quantized energy equals H Nu this is the + + align:start position:0% +quantized energy equals H Nu this is the + + + align:start position:0% +quantized energy equals H Nu this is the +modern derivation that we inherit and + + align:start position:0% +modern derivation that we inherit and + + + align:start position:0% +modern derivation that we inherit and +use today that's much more like the + + align:start position:0% +use today that's much more like the + + + align:start position:0% +use today that's much more like the +derivation I give in those brief + + align:start position:0% +derivation I give in those brief + + + align:start position:0% +derivation I give in those brief +optional notes so in the same article + + align:start position:0% +optional notes so in the same article + + + align:start position:0% +optional notes so in the same article +Einstein both kind of offers a heuristic + + align:start position:0% +Einstein both kind of offers a heuristic + + + align:start position:0% +Einstein both kind of offers a heuristic +explanation for Leonard's otherwise + + align:start position:0% +explanation for Leonard's otherwise + + + align:start position:0% +explanation for Leonard's otherwise +quite puzzling experiment results he + + align:start position:0% +quite puzzling experiment results he + + + align:start position:0% +quite puzzling experiment results he +revisits and kind of reinterprets clocks + + align:start position:0% +revisits and kind of reinterprets clocks + + + align:start position:0% +revisits and kind of reinterprets clocks +own by now rather a well-known + + align:start position:0% +own by now rather a well-known + + + align:start position:0% +own by now rather a well-known +expression for Black by variation all + + align:start position:0% +expression for Black by variation all + + + align:start position:0% +expression for Black by variation all +from the starting point of view that + + align:start position:0% +from the starting point of view that + + + align:start position:0% +from the starting point of view that +light is quantized and each individual + + align:start position:0% +light is quantized and each individual + + + align:start position:0% +light is quantized and each individual +like Quantum carries a unit amount of + + align:start position:0% +like Quantum carries a unit amount of + + + align:start position:0% +like Quantum carries a unit amount of +energy set by H Nu so we might figure + + align:start position:0% +energy set by H Nu so we might figure + + + align:start position:0% +energy set by H Nu so we might figure +okay he solved everything everyone must + + align:start position:0% +okay he solved everything everyone must + + + align:start position:0% +okay he solved everything everyone must +have been convinced right + + align:start position:0% +have been convinced right + + + align:start position:0% +have been convinced right +no no no we've learned from this course + + align:start position:0% +no no no we've learned from this course + + + align:start position:0% +no no no we've learned from this course +already things you hardly are hardly + + align:start position:0% +already things you hardly are hardly + + + align:start position:0% +already things you hardly are hardly +ever work that way and in Einstein's + + align:start position:0% +ever work that way and in Einstein's + + + align:start position:0% +ever work that way and in Einstein's +case in particular remember he was still + + align:start position:0% +case in particular remember he was still + + + align:start position:0% +case in particular remember he was still +a little-known patent clerk kind of out + + align:start position:0% +a little-known patent clerk kind of out + + + align:start position:0% +a little-known patent clerk kind of out +of the of the main Elite centers of + + align:start position:0% +of the of the main Elite centers of + + + align:start position:0% +of the of the main Elite centers of +research + + align:start position:0% +research + + + align:start position:0% +research +this was facing enormous skepticism even + + align:start position:0% +this was facing enormous skepticism even + + + align:start position:0% +this was facing enormous skepticism even +years after Einstein himself became much + + align:start position:0% +years after Einstein himself became much + + + align:start position:0% +years after Einstein himself became much +more prominent it was really more than + + align:start position:0% +more prominent it was really more than + + + align:start position:0% +more prominent it was really more than +15 years until the majority of members + + align:start position:0% +15 years until the majority of members + + + align:start position:0% +15 years until the majority of members +of the physics Community really took + + align:start position:0% +of the physics Community really took + + + align:start position:0% +of the physics Community really took +this idea at all seriously and here's + + align:start position:0% +this idea at all seriously and here's + + + align:start position:0% +this idea at all seriously and here's +again one of my favorite examples of + + align:start position:0% +again one of my favorite examples of + + + align:start position:0% +again one of my favorite examples of +that here's our again our old friend box + + align:start position:0% +that here's our again our old friend box + + + align:start position:0% +that here's our again our old friend box +plug writing this is a letter of + + align:start position:0% +plug writing this is a letter of + + + align:start position:0% +plug writing this is a letter of +recommendation he's trying to say how + + align:start position:0% +recommendation he's trying to say how + + + align:start position:0% +recommendation he's trying to say how +great Einstein's work is by 1913. how + + align:start position:0% +great Einstein's work is by 1913. how + + + align:start position:0% +great Einstein's work is by 1913. how +does Einstein is no longer the unknown + + align:start position:0% +does Einstein is no longer the unknown + + + align:start position:0% +does Einstein is no longer the unknown +patent click + + align:start position:0% +patent click + + + align:start position:0% +patent click +Clark was trying to convince his + + align:start position:0% +Clark was trying to convince his + + + align:start position:0% +Clark was trying to convince his +colleagues to offer a very prestigious + + align:start position:0% +colleagues to offer a very prestigious + + + align:start position:0% +colleagues to offer a very prestigious +new job to Einstein at the Prussian + + align:start position:0% +new job to Einstein at the Prussian + + + align:start position:0% +new job to Einstein at the Prussian +Academy of Sciences which in fact + + align:start position:0% +Academy of Sciences which in fact + + + align:start position:0% +Academy of Sciences which in fact +Einstein would would soon be offered + + align:start position:0% +Einstein would would soon be offered + + + align:start position:0% +Einstein would would soon be offered +we'd move to Berlin and in his letter + + align:start position:0% +we'd move to Berlin and in his letter + + + align:start position:0% +we'd move to Berlin and in his letter +saying how great Einstein's work is + + align:start position:0% +saying how great Einstein's work is + + + align:start position:0% +saying how great Einstein's work is +plugs as the following in some one can + + align:start position:0% +plugs as the following in some one can + + + align:start position:0% +plugs as the following in some one can +say there is hardly one among the great + + align:start position:0% +say there is hardly one among the great + + + align:start position:0% +say there is hardly one among the great +problems in which modern physics is so + + align:start position:0% +problems in which modern physics is so + + + align:start position:0% +problems in which modern physics is so +rich to which eyesight has not made a + + align:start position:0% +rich to which eyesight has not made a + + + align:start position:0% +rich to which eyesight has not made a +remarkable contribution that sounds nice + + align:start position:0% +remarkable contribution that sounds nice + + + align:start position:0% +remarkable contribution that sounds nice +that he may sometimes have missed the + + align:start position:0% +that he may sometimes have missed the + + + align:start position:0% +that he may sometimes have missed the +Target in his speculations as for + + align:start position:0% +Target in his speculations as for + + + align:start position:0% +Target in his speculations as for +example in his hypothesis of like quanta + + align:start position:0% +example in his hypothesis of like quanta + + + align:start position:0% +example in his hypothesis of like quanta +cannot really be held too much against + + align:start position:0% +cannot really be held too much against + + + align:start position:0% +cannot really be held too much against +him which is to say a lot of the work + + align:start position:0% +him which is to say a lot of the work + + + align:start position:0% +him which is to say a lot of the work +this person has done is very interesting + + align:start position:0% +this person has done is very interesting + + + align:start position:0% +this person has done is very interesting +he's clearly mistaken about light quanta + + align:start position:0% +he's clearly mistaken about light quanta + + + align:start position:0% +he's clearly mistaken about light quanta +but let's let him into our new club + + align:start position:0% +but let's let him into our new club + + + align:start position:0% +but let's let him into our new club +anyway I find that terrific okay let me + + align:start position:0% +anyway I find that terrific okay let me + + + align:start position:0% +anyway I find that terrific okay let me +pause there again ask any questions on + + align:start position:0% +pause there again ask any questions on + + + align:start position:0% +pause there again ask any questions on +the like Quantum work + + align:start position:0% + + + + align:start position:0% + +Fisher asks in Einstein's paper + + align:start position:0% +Fisher asks in Einstein's paper + + + align:start position:0% +Fisher asks in Einstein's paper +it didn't make any nods in Newton's + + align:start position:0% +it didn't make any nods in Newton's + + + align:start position:0% +it didn't make any nods in Newton's +original thought that life was Corpus + + align:start position:0% +original thought that life was Corpus + + + align:start position:0% +original thought that life was Corpus +was very good honestly I don't remember + + align:start position:0% +was very good honestly I don't remember + + + align:start position:0% +was very good honestly I don't remember +that's an excellent question let me back + + align:start position:0% +that's an excellent question let me back + + + align:start position:0% +that's an excellent question let me back +up others might know as well it was + + align:start position:0% +up others might know as well it was + + + align:start position:0% +up others might know as well it was +worth emphasizing the the big picture + + align:start position:0% +worth emphasizing the the big picture + + + align:start position:0% +worth emphasizing the the big picture +question it does light consist of waves + + align:start position:0% +question it does light consist of waves + + + align:start position:0% +question it does light consist of waves +or particles that actually has a really + + align:start position:0% +or particles that actually has a really + + + align:start position:0% +or particles that actually has a really +long history I guess I gave a little + + align:start position:0% +long history I guess I gave a little + + + align:start position:0% +long history I guess I gave a little +preview of that although I didn't Linger + + align:start position:0% +preview of that although I didn't Linger + + + align:start position:0% +preview of that although I didn't Linger +on it even in one of our first class + + align:start position:0% +on it even in one of our first class + + + align:start position:0% +on it even in one of our first class +sessions for this class you might know + + align:start position:0% +sessions for this class you might know + + + align:start position:0% +sessions for this class you might know +from other readings or other classes + + align:start position:0% +from other readings or other classes + + + align:start position:0% +from other readings or other classes +the reason was actually a big deal + + align:start position:0% +the reason was actually a big deal + + + align:start position:0% +the reason was actually a big deal +around 1800 going back to sort of early + + align:start position:0% +around 1800 going back to sort of early + + + align:start position:0% +around 1800 going back to sort of early +in what Michael Faraday's own career it + + align:start position:0% +in what Michael Faraday's own career it + + + align:start position:0% +in what Michael Faraday's own career it +was a big deal to think of light as + + align:start position:0% +was a big deal to think of light as + + + align:start position:0% +was a big deal to think of light as +waves because since at least Newton's + + align:start position:0% +waves because since at least Newton's + + + align:start position:0% +waves because since at least Newton's +day another century and a quarter before + + align:start position:0% +day another century and a quarter before + + + align:start position:0% +day another century and a quarter before +that going back to the later years of + + align:start position:0% +that going back to the later years of + + + align:start position:0% +that going back to the later years of +the 17th century the 1660s and so on + + align:start position:0% +the 17th century the 1660s and so on + + + align:start position:0% +the 17th century the 1660s and so on +Newton and other leading Scholars had + + align:start position:0% +Newton and other leading Scholars had + + + align:start position:0% +Newton and other leading Scholars had +convinced themselves the light actually + + align:start position:0% +convinced themselves the light actually + + + align:start position:0% +convinced themselves the light actually +consisted of a stream of particles + + align:start position:0% +consisted of a stream of particles + + + align:start position:0% +consisted of a stream of particles +Newton called them corpuscles exactly as + + align:start position:0% +Newton called them corpuscles exactly as + + + align:start position:0% +Newton called them corpuscles exactly as +Fisher says so Newton was convinced that + + align:start position:0% +Fisher says so Newton was convinced that + + + align:start position:0% +Fisher says so Newton was convinced that +light was corpuscular we might now say + + align:start position:0% +light was corpuscular we might now say + + + align:start position:0% +light was corpuscular we might now say +the light was made up of a stream of + + align:start position:0% +the light was made up of a stream of + + + align:start position:0% +the light was made up of a stream of +particles that's in 1660s 70s 80s would + + align:start position:0% +particles that's in 1660s 70s 80s would + + + align:start position:0% +particles that's in 1660s 70s 80s would +become super influential he writes a + + align:start position:0% +become super influential he writes a + + + align:start position:0% +become super influential he writes a +whole book called Optics Newton does + + align:start position:0% +whole book called Optics Newton does + + + align:start position:0% +whole book called Optics Newton does +first published in round 1703 or + + align:start position:0% +first published in round 1703 or + + + align:start position:0% +first published in round 1703 or +something like that I was like okay + + align:start position:0% +something like that I was like okay + + + align:start position:0% +something like that I was like okay +Newton has spoken lights particles got + + align:start position:0% +Newton has spoken lights particles got + + + align:start position:0% +Newton has spoken lights particles got +it + + align:start position:0% +it + + + align:start position:0% +it +and so it was a pretty big deal when + + align:start position:0% +and so it was a pretty big deal when + + + align:start position:0% +and so it was a pretty big deal when +about a hundred years after that the + + align:start position:0% +about a hundred years after that the + + + align:start position:0% +about a hundred years after that the +consensus shifts both in Britain and in + + align:start position:0% +consensus shifts both in Britain and in + + + align:start position:0% +consensus shifts both in Britain and in +France and ultimately many many other + + align:start position:0% +France and ultimately many many other + + + align:start position:0% +France and ultimately many many other +places but hang on light seems to have + + align:start position:0% +places but hang on light seems to have + + + align:start position:0% +places but hang on light seems to have +all these wave-like properties like + + align:start position:0% +all these wave-like properties like + + + align:start position:0% +all these wave-like properties like +interference and diffraction and + + align:start position:0% +interference and diffraction and + + + align:start position:0% +interference and diffraction and +refraction and all these things that + + align:start position:0% +refraction and all these things that + + + align:start position:0% +refraction and all these things that +helped set in motion the ideas of a + + align:start position:0% +helped set in motion the ideas of a + + + align:start position:0% +helped set in motion the ideas of a +light-bearing ether if light is a wave + + align:start position:0% +light-bearing ether if light is a wave + + + align:start position:0% +light-bearing ether if light is a wave +what does it wave in so you have these + + align:start position:0% +what does it wave in so you have these + + + align:start position:0% +what does it wave in so you have these +huge kind of century long shifts between + + align:start position:0% +huge kind of century long shifts between + + + align:start position:0% +huge kind of century long shifts between +assumptions about just what's light made + + align:start position:0% +assumptions about just what's light made + + + align:start position:0% +assumptions about just what's light made +of in general let alone these specific + + align:start position:0% +of in general let alone these specific + + + align:start position:0% +of in general let alone these specific +questions about how it interacts with + + align:start position:0% +questions about how it interacts with + + + align:start position:0% +questions about how it interacts with +matter + + align:start position:0% +matter + + + align:start position:0% +matter +so it was certainly well known well + + align:start position:0% +so it was certainly well known well + + + align:start position:0% +so it was certainly well known well +before Einstein's day that Newton had + + align:start position:0% +before Einstein's day that Newton had + + + align:start position:0% +before Einstein's day that Newton had +been let's say a corpuscularist but it's + + align:start position:0% +been let's say a corpuscularist but it's + + + align:start position:0% +been let's say a corpuscularist but it's +a great question Fisher and I'd have to + + align:start position:0% +a great question Fisher and I'd have to + + + align:start position:0% +a great question Fisher and I'd have to +go back to my own copy uh in English + + align:start position:0% +go back to my own copy uh in English + + + align:start position:0% +go back to my own copy uh in English +translation my German to see whether + + align:start position:0% +translation my German to see whether + + + align:start position:0% +translation my German to see whether +Einstein paused to to reflect on that I + + align:start position:0% +Einstein paused to to reflect on that I + + + align:start position:0% +Einstein paused to to reflect on that I +don't remember interesting question + + align:start position:0% +don't remember interesting question + + + align:start position:0% +don't remember interesting question +uh Gary asked having written as a + + align:start position:0% +uh Gary asked having written as a + + + align:start position:0% +uh Gary asked having written as a +heuristic did Einstein believe it'd be + + align:start position:0% +heuristic did Einstein believe it'd be + + + align:start position:0% +heuristic did Einstein believe it'd be +quantitative fiber only later very good + + align:start position:0% +quantitative fiber only later very good + + + align:start position:0% +quantitative fiber only later very good +carry so my best understanding uh and + + align:start position:0% +carry so my best understanding uh and + + + align:start position:0% +carry so my best understanding uh and +again I haven't looked has directly in + + align:start position:0% +again I haven't looked has directly in + + + align:start position:0% +again I haven't looked has directly in +this but from my colleagues who have + + align:start position:0% +this but from my colleagues who have + + + align:start position:0% +this but from my colleagues who have +really poured over Einstein's + + align:start position:0% +really poured over Einstein's + + + align:start position:0% +really poured over Einstein's +um uh at the time unpublished + + align:start position:0% +um uh at the time unpublished + + + align:start position:0% +um uh at the time unpublished +correspondence his notes and so again we + + align:start position:0% +correspondence his notes and so again we + + + align:start position:0% +correspondence his notes and so again we +have a huge documentary base of how his + + align:start position:0% +have a huge documentary base of how his + + + align:start position:0% +have a huge documentary base of how his +thinking was evolving in those years + + align:start position:0% +thinking was evolving in those years + + + align:start position:0% +thinking was evolving in those years +it seems that Einstein thought this + + align:start position:0% +it seems that Einstein thought this + + + align:start position:0% +it seems that Einstein thought this +really really was true but for once he + + align:start position:0% +really really was true but for once he + + + align:start position:0% +really really was true but for once he +kind of hedged uh rhetorically so it + + align:start position:0% +kind of hedged uh rhetorically so it + + + align:start position:0% +kind of hedged uh rhetorically so it +seems that he was offering a heuristic + + align:start position:0% +seems that he was offering a heuristic + + + align:start position:0% +seems that he was offering a heuristic +explanation and going through actually a + + align:start position:0% +explanation and going through actually a + + + align:start position:0% +explanation and going through actually a +whole number of of episodes or scenarios + + align:start position:0% +whole number of of episodes or scenarios + + + align:start position:0% +whole number of of episodes or scenarios +where this suggestive hypothesis might + + align:start position:0% +where this suggestive hypothesis might + + + align:start position:0% +where this suggestive hypothesis might +be helpful + + align:start position:0% +be helpful + + + align:start position:0% +be helpful +but it seems that he was + + align:start position:0% +but it seems that he was + + + align:start position:0% +but it seems that he was +um he thought there was that this was + + align:start position:0% +um he thought there was that this was + + + align:start position:0% +um he thought there was that this was +not only a fiction + + align:start position:0% +not only a fiction + + + align:start position:0% +not only a fiction +uh he was however not sure how to square + + align:start position:0% +uh he was however not sure how to square + + + align:start position:0% +uh he was however not sure how to square +this in 1905 he wasn't sure how to + + align:start position:0% +this in 1905 he wasn't sure how to + + + align:start position:0% +this in 1905 he wasn't sure how to +square that with a centuries worth of + + align:start position:0% +square that with a centuries worth of + + + align:start position:0% +square that with a centuries worth of +evidence that light had wave-like + + align:start position:0% +evidence that light had wave-like + + + align:start position:0% +evidence that light had wave-like +Behavior like reflection refraction + + align:start position:0% +Behavior like reflection refraction + + + align:start position:0% +Behavior like reflection refraction +diffraction + + align:start position:0% +diffraction + + + align:start position:0% +diffraction +interference in general so it's not that + + align:start position:0% +interference in general so it's not that + + + align:start position:0% +interference in general so it's not that +I said uh there's nothing ever wavy + + align:start position:0% +I said uh there's nothing ever wavy + + + align:start position:0% +I said uh there's nothing ever wavy +about light you know it's always only + + align:start position:0% +about light you know it's always only + + + align:start position:0% +about light you know it's always only +particles but he was certainly and in + + align:start position:0% +particles but he was certainly and in + + + align:start position:0% +particles but he was certainly and in +his own kind of more private musings he + + align:start position:0% +his own kind of more private musings he + + + align:start position:0% +his own kind of more private musings he +seemed to think that one had to adopt + + align:start position:0% +seemed to think that one had to adopt + + + align:start position:0% +seemed to think that one had to adopt +these um it's really like particles a + + align:start position:0% +these um it's really like particles a + + + align:start position:0% +these um it's really like particles a +position in some scenarios more than + + align:start position:0% +position in some scenarios more than + + + align:start position:0% +position in some scenarios more than +others he was groping toward what we + + align:start position:0% +others he was groping toward what we + + + align:start position:0% +others he was groping toward what we +what what we see actually in the next + + align:start position:0% +what what we see actually in the next + + + align:start position:0% +what what we see actually in the next +part of today's class and it will chase + + align:start position:0% +part of today's class and it will chase + + + align:start position:0% +part of today's class and it will chase +us through upcoming class sessions he + + align:start position:0% +us through upcoming class sessions he + + + align:start position:0% +us through upcoming class sessions he +was beginning to Grapple with what would + + align:start position:0% +was beginning to Grapple with what would + + + align:start position:0% +was beginning to Grapple with what would +come to be called wave particle duality + + align:start position:0% +come to be called wave particle duality + + + align:start position:0% +come to be called wave particle duality +he certainly wasn't calling that yet in + + align:start position:0% +he certainly wasn't calling that yet in + + + align:start position:0% +he certainly wasn't calling that yet in +1905 but he was already as as his + + align:start position:0% +1905 but he was already as as his + + + align:start position:0% +1905 but he was already as as his +additional kind of documents from the + + align:start position:0% +additional kind of documents from the + + + align:start position:0% +additional kind of documents from the +time seemed to suggest + + align:start position:0% +time seemed to suggest + + + align:start position:0% +time seemed to suggest +he was already grappling with we really + + align:start position:0% +he was already grappling with we really + + + align:start position:0% +he was already grappling with we really +really need to treat light like waves + + align:start position:0% +really need to treat light like waves + + + align:start position:0% +really need to treat light like waves +for certain scenarios interference + + align:start position:0% +for certain scenarios interference + + + align:start position:0% +for certain scenarios interference +fringes being an obvious one and yet he + + align:start position:0% +fringes being an obvious one and yet he + + + align:start position:0% +fringes being an obvious one and yet he +in his own kind of you know heart of + + align:start position:0% +in his own kind of you know heart of + + + align:start position:0% +in his own kind of you know heart of +hearts he seemed pretty convinced that + + align:start position:0% +hearts he seemed pretty convinced that + + + align:start position:0% +hearts he seemed pretty convinced that +this corpuscular or Quantum nature + + align:start position:0% +this corpuscular or Quantum nature + + + align:start position:0% +this corpuscular or Quantum nature +seemed more than just a coincidence in + + align:start position:0% +seemed more than just a coincidence in + + + align:start position:0% +seemed more than just a coincidence in +other kinds of scenarios and that would + + align:start position:0% +other kinds of scenarios and that would + + + align:start position:0% +other kinds of scenarios and that would +kind of become um more and more of a + + align:start position:0% +kind of become um more and more of a + + + align:start position:0% +kind of become um more and more of a +a paradox to some or a challenge even + + align:start position:0% +a paradox to some or a challenge even + + + align:start position:0% +a paradox to some or a challenge even +Beyond Einstein himself + + align:start position:0% +Beyond Einstein himself + + + align:start position:0% +Beyond Einstein himself +and so the real question actually + + align:start position:0% +and so the real question actually + + + align:start position:0% +and so the real question actually +becomes why was Einstein hedging his + + align:start position:0% +becomes why was Einstein hedging his + + + align:start position:0% +becomes why was Einstein hedging his +bets rhetorically rather than what did + + align:start position:0% +bets rhetorically rather than what did + + + align:start position:0% +bets rhetorically rather than what did +he really believe because we saw in in + + align:start position:0% +he really believe because we saw in in + + + align:start position:0% +he really believe because we saw in in +his paper just a few weeks later that he + + align:start position:0% +his paper just a few weeks later that he + + + align:start position:0% +his paper just a few weeks later that he +submits on the electrodynamics of living + + align:start position:0% +submits on the electrodynamics of living + + + align:start position:0% +submits on the electrodynamics of living +bodies he's certainly not shy about + + align:start position:0% +bodies he's certainly not shy about + + + align:start position:0% +bodies he's certainly not shy about +dismissing The Ether he's making other + + align:start position:0% +dismissing The Ether he's making other + + + align:start position:0% +dismissing The Ether he's making other +rather bold and almost almost like + + align:start position:0% +rather bold and almost almost like + + + align:start position:0% +rather bold and almost almost like +irresponsible statements uh given the + + align:start position:0% +irresponsible statements uh given the + + + align:start position:0% +irresponsible statements uh given the +standard assumptions of his day he + + align:start position:0% +standard assumptions of his day he + + + align:start position:0% +standard assumptions of his day he +wasn't shy in 1905. with this particular + + align:start position:0% +wasn't shy in 1905. with this particular + + + align:start position:0% +wasn't shy in 1905. with this particular +one I imagine it was more like he didn't + + align:start position:0% +one I imagine it was more like he didn't + + + align:start position:0% +one I imagine it was more like he didn't +yet know how to square the circle here + + align:start position:0% +yet know how to square the circle here + + + align:start position:0% +yet know how to square the circle here +of what comes to be known as wave + + align:start position:0% +of what comes to be known as wave + + + align:start position:0% +of what comes to be known as wave +particle duality so that's a great + + align:start position:0% +particle duality so that's a great + + + align:start position:0% +particle duality so that's a great +question again we'll see an example of + + align:start position:0% +question again we'll see an example of + + + align:start position:0% +question again we'll see an example of +that even in the next part today and and + + align:start position:0% +that even in the next part today and and + + + align:start position:0% +that even in the next part today and and +we'll see Echoes of that throughout the + + align:start position:0% +we'll see Echoes of that throughout the + + + align:start position:0% +we'll see Echoes of that throughout the +next few classes + + align:start position:0% +next few classes + + + align:start position:0% +next few classes +any other questions on on the + + align:start position:0% +any other questions on on the + + + align:start position:0% +any other questions on on the +photoelectric effect on what was Leonard + + align:start position:0% +photoelectric effect on what was Leonard + + + align:start position:0% +photoelectric effect on what was Leonard +measuring + + align:start position:0% +measuring + + + align:start position:0% +measuring +on Einstein's explanation it's all + + align:start position:0% +on Einstein's explanation it's all + + + align:start position:0% +on Einstein's explanation it's all +pretty clear + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +great good questions + + align:start position:0% +great good questions + + + align:start position:0% +great good questions +let's look at this last part for today + + align:start position:0% +let's look at this last part for today + + + align:start position:0% +let's look at this last part for today +why did anyone begin to take light quads + + align:start position:0% +why did anyone begin to take light quads + + + align:start position:0% +why did anyone begin to take light quads +up a bit more seriously one of the most + + align:start position:0% +up a bit more seriously one of the most + + + align:start position:0% +up a bit more seriously one of the most +compelling uh sort of sets of new + + align:start position:0% +compelling uh sort of sets of new + + + align:start position:0% +compelling uh sort of sets of new +information new inputs for this + + align:start position:0% +information new inputs for this + + + align:start position:0% +information new inputs for this +came yet again from a laboratory in the + + align:start position:0% +came yet again from a laboratory in the + + + align:start position:0% +came yet again from a laboratory in the +United States which again is itself + + align:start position:0% +United States which again is itself + + + align:start position:0% +United States which again is itself +still pretty unusual this was among the + + align:start position:0% +still pretty unusual this was among the + + + align:start position:0% +still pretty unusual this was among the +next set of really significant + + align:start position:0% +next set of really significant + + + align:start position:0% +next set of really significant +experimental work in physics that got uh + + align:start position:0% +experimental work in physics that got uh + + + align:start position:0% +experimental work in physics that got uh +even the experts sometimes very snobby + + align:start position:0% +even the experts sometimes very snobby + + + align:start position:0% +even the experts sometimes very snobby +experts uh in Western Europe to pay + + align:start position:0% +experts uh in Western Europe to pay + + + align:start position:0% +experts uh in Western Europe to pay +attention this is now decades after + + align:start position:0% +attention this is now decades after + + + align:start position:0% +attention this is now decades after +Albert Michelson and the Michael symbol + + align:start position:0% +Albert Michelson and the Michael symbol + + + align:start position:0% +Albert Michelson and the Michael symbol +experiment is now the early 1920s not + + align:start position:0% +experiment is now the early 1920s not + + + align:start position:0% +experiment is now the early 1920s not +the 1880s but this was again an example + + align:start position:0% +the 1880s but this was again an example + + + align:start position:0% +the 1880s but this was again an example +held up almost immediately for for real + + align:start position:0% +held up almost immediately for for real + + + align:start position:0% +held up almost immediately for for real +acclaim + + align:start position:0% +acclaim + + + align:start position:0% +acclaim +a series of experiments performed by the + + align:start position:0% +a series of experiments performed by the + + + align:start position:0% +a series of experiments performed by the +physicist Arthur Compton at the + + align:start position:0% +physicist Arthur Compton at the + + + align:start position:0% +physicist Arthur Compton at the +University of Chicago in 1922. here's + + align:start position:0% +University of Chicago in 1922. here's + + + align:start position:0% +University of Chicago in 1922. here's +Compton he looks like a kind of movie + + align:start position:0% +Compton he looks like a kind of movie + + + align:start position:0% +Compton he looks like a kind of movie +star you might recognize the name + + align:start position:0% +star you might recognize the name + + + align:start position:0% +star you might recognize the name +Compton Arthur's brother was Carl + + align:start position:0% +Compton Arthur's brother was Carl + + + align:start position:0% +Compton Arthur's brother was Carl +Compton also of trained physicist Carl + + align:start position:0% +Compton also of trained physicist Carl + + + align:start position:0% +Compton also of trained physicist Carl +Compton then went on to a different kind + + align:start position:0% +Compton then went on to a different kind + + + align:start position:0% +Compton then went on to a different kind +of career he became the president of MIT + + align:start position:0% +of career he became the president of MIT + + + align:start position:0% +of career he became the president of MIT +starting in 1930 and you served for + + align:start position:0% +starting in 1930 and you served for + + + align:start position:0% +starting in 1930 and you served for +nearly 20 years + + align:start position:0% +nearly 20 years + + + align:start position:0% +nearly 20 years +so a number of enormous enormously + + align:start position:0% +so a number of enormous enormously + + + align:start position:0% +so a number of enormous enormously +consequential reforms at MIT were put in + + align:start position:0% +consequential reforms at MIT were put in + + + align:start position:0% +consequential reforms at MIT were put in +place by Carl Compton just at the + + align:start position:0% +place by Carl Compton just at the + + + align:start position:0% +place by Carl Compton just at the +moments are around the same time that + + align:start position:0% +moments are around the same time that + + + align:start position:0% +moments are around the same time that +his brother Arthur Compton was + + align:start position:0% +his brother Arthur Compton was + + + align:start position:0% +his brother Arthur Compton was +experimenting on the nature of light and + + align:start position:0% +experimenting on the nature of light and + + + align:start position:0% +experimenting on the nature of light and +again as I say this was one of the sets + + align:start position:0% +again as I say this was one of the sets + + + align:start position:0% +again as I say this was one of the sets +of new kind of inputs coming out of U.S + + align:start position:0% +of new kind of inputs coming out of U.S + + + align:start position:0% +of new kind of inputs coming out of U.S +based Laboratories that really began to + + align:start position:0% +based Laboratories that really began to + + + align:start position:0% +based Laboratories that really began to +make even experts in Europe uh pay close + + align:start position:0% +make even experts in Europe uh pay close + + + align:start position:0% +make even experts in Europe uh pay close +attention + + align:start position:0% +attention + + + align:start position:0% +attention +so Compton Arthur Compton had not set + + align:start position:0% +so Compton Arthur Compton had not set + + + align:start position:0% +so Compton Arthur Compton had not set +out to test Einstein's hypothesis he + + align:start position:0% +out to test Einstein's hypothesis he + + + align:start position:0% +out to test Einstein's hypothesis he +like everyone practically everyone in + + align:start position:0% +like everyone practically everyone in + + + align:start position:0% +like everyone practically everyone in +the field remained pretty skeptical much + + align:start position:0% +the field remained pretty skeptical much + + + align:start position:0% +the field remained pretty skeptical much +like in that letter uh from from Max + + align:start position:0% +like in that letter uh from from Max + + + align:start position:0% +like in that letter uh from from Max +Planck from 1913. they figured Einstein + + align:start position:0% +Planck from 1913. they figured Einstein + + + align:start position:0% +Planck from 1913. they figured Einstein +by this point had was pretty smart had + + align:start position:0% +by this point had was pretty smart had + + + align:start position:0% +by this point had was pretty smart had +some amazing um successes to his career + + align:start position:0% +some amazing um successes to his career + + + align:start position:0% +some amazing um successes to his career +but this light Quantum thing was + + align:start position:0% +but this light Quantum thing was + + + align:start position:0% +but this light Quantum thing was +probably not one of them + + align:start position:0% +probably not one of them + + + align:start position:0% +probably not one of them +competency I was really interested in + + align:start position:0% +competency I was really interested in + + + align:start position:0% +competency I was really interested in +the behavior of high energy X-rays and + + align:start position:0% +the behavior of high energy X-rays and + + + align:start position:0% +the behavior of high energy X-rays and +how these x-rays would interact with + + align:start position:0% +how these x-rays would interact with + + + align:start position:0% +how these x-rays would interact with +little bits of matter so he was + + align:start position:0% +little bits of matter so he was + + + align:start position:0% +little bits of matter so he was +conducting experience by basically + + align:start position:0% +conducting experience by basically + + + align:start position:0% +conducting experience by basically +beaming x-rays very high energy + + align:start position:0% +beaming x-rays very high energy + + + align:start position:0% +beaming x-rays very high energy +electromagnetic light as far as he was + + align:start position:0% +electromagnetic light as far as he was + + + align:start position:0% +electromagnetic light as far as he was +concerned maxwellian waves a very short + + align:start position:0% +concerned maxwellian waves a very short + + + align:start position:0% +concerned maxwellian waves a very short +wavelength very high frequency + + align:start position:0% +wavelength very high frequency + + + align:start position:0% +wavelength very high frequency +and bouncing them off of graphite + + align:start position:0% +and bouncing them off of graphite + + + align:start position:0% +and bouncing them off of graphite +basically carbon molecules uh so we + + align:start position:0% +basically carbon molecules uh so we + + + align:start position:0% +basically carbon molecules uh so we +wanted to bounce them off the electrons + + align:start position:0% +wanted to bounce them off the electrons + + + align:start position:0% +wanted to bounce them off the electrons +in carbon + + align:start position:0% +in carbon + + + align:start position:0% +in carbon +what Compton was measuring in particular + + align:start position:0% +what Compton was measuring in particular + + + align:start position:0% +what Compton was measuring in particular +was change in the wavelength in the + + align:start position:0% +was change in the wavelength in the + + + align:start position:0% +was change in the wavelength in the +wavelength of those uh electromagnetic + + align:start position:0% +wavelength of those uh electromagnetic + + + align:start position:0% +wavelength of those uh electromagnetic +waves the x-rays after scattering so + + align:start position:0% +waves the x-rays after scattering so + + + align:start position:0% +waves the x-rays after scattering so +remote you're familiar of course for any + + align:start position:0% +remote you're familiar of course for any + + + align:start position:0% +remote you're familiar of course for any +of these maxwellian waves we can measure + + align:start position:0% +of these maxwellian waves we can measure + + + align:start position:0% +of these maxwellian waves we can measure +the wavelength the distance uh the + + align:start position:0% +the wavelength the distance uh the + + + align:start position:0% +the wavelength the distance uh the +physical distance between neighboring + + align:start position:0% +physical distance between neighboring + + + align:start position:0% +physical distance between neighboring +crests neighboring peaks of say the + + align:start position:0% +crests neighboring peaks of say the + + + align:start position:0% +crests neighboring peaks of say the +associated electric field so what + + align:start position:0% +associated electric field so what + + + align:start position:0% +associated electric field so what +Compton was doing in his laboratory was + + align:start position:0% +Compton was doing in his laboratory was + + + align:start position:0% +Compton was doing in his laboratory was +measuring the wavelength prior to + + align:start position:0% +measuring the wavelength prior to + + + align:start position:0% +measuring the wavelength prior to +scattering and the way the shifted + + align:start position:0% +scattering and the way the shifted + + + align:start position:0% +scattering and the way the shifted +wavelength following scattering so the + + align:start position:0% +wavelength following scattering so the + + + align:start position:0% +wavelength following scattering so the +prime here means after the scattering he + + align:start position:0% +prime here means after the scattering he + + + align:start position:0% +prime here means after the scattering he +knew the wavelength ahead of time he + + align:start position:0% +knew the wavelength ahead of time he + + + align:start position:0% +knew the wavelength ahead of time he +could control that with his apparatus he + + align:start position:0% +could control that with his apparatus he + + + align:start position:0% +could control that with his apparatus he +could then use very much like the pgr it + + align:start position:0% +could then use very much like the pgr it + + + align:start position:0% +could then use very much like the pgr it +could use very finely spaced diffraction + + align:start position:0% +could use very finely spaced diffraction + + + align:start position:0% +could use very finely spaced diffraction +gratings and similar techniques to + + align:start position:0% +gratings and similar techniques to + + + align:start position:0% +gratings and similar techniques to +measure the shift in wavelength after + + align:start position:0% +measure the shift in wavelength after + + + align:start position:0% +measure the shift in wavelength after +the x-rays have basically scattered off + + align:start position:0% +the x-rays have basically scattered off + + + align:start position:0% +the x-rays have basically scattered off +these electrons + + align:start position:0% +these electrons + + + align:start position:0% +these electrons +he found that there was a shift the the + + align:start position:0% +he found that there was a shift the the + + + align:start position:0% +he found that there was a shift the the +wavelength following Collision was not + + align:start position:0% +wavelength following Collision was not + + + align:start position:0% +wavelength following Collision was not +equal to the wavelength prior to + + align:start position:0% +equal to the wavelength prior to + + + align:start position:0% +equal to the wavelength prior to +Collision and it was a very specific + + align:start position:0% +Collision and it was a very specific + + + align:start position:0% +Collision and it was a very specific +angular dependence that the angle at + + align:start position:0% +angular dependence that the angle at + + + align:start position:0% +angular dependence that the angle at +which these x-rays bounced off is angle + + align:start position:0% +which these x-rays bounced off is angle + + + align:start position:0% +which these x-rays bounced off is angle +Theta uh was somehow related to this + + align:start position:0% +Theta uh was somehow related to this + + + align:start position:0% +Theta uh was somehow related to this +degree in which their wavelength changed + + align:start position:0% +degree in which their wavelength changed + + + align:start position:0% +degree in which their wavelength changed +and that is to say the shift in + + align:start position:0% +and that is to say the shift in + + + align:start position:0% +and that is to say the shift in +wavelength went like one minus cosine of + + align:start position:0% +wavelength went like one minus cosine of + + + align:start position:0% +wavelength went like one minus cosine of +the light waves scattering angle and + + align:start position:0% +the light waves scattering angle and + + + align:start position:0% +the light waves scattering angle and +that's what you can measure you can see + + align:start position:0% +that's what you can measure you can see + + + align:start position:0% +that's what you can measure you can see +here it's mounted on a wheel it could + + align:start position:0% +here it's mounted on a wheel it could + + + align:start position:0% +here it's mounted on a wheel it could +actually pivot his kind of diffraction + + align:start position:0% +actually pivot his kind of diffraction + + + align:start position:0% +actually pivot his kind of diffraction +gratings essentially and measure the + + align:start position:0% +gratings essentially and measure the + + + align:start position:0% +gratings essentially and measure the +scattered light at different angles as + + align:start position:0% +scattered light at different angles as + + + align:start position:0% +scattered light at different angles as +it bounced off that graphite Target + + align:start position:0% +it bounced off that graphite Target + + + align:start position:0% +it bounced off that graphite Target +so Compton was convinced this could be + + align:start position:0% +so Compton was convinced this could be + + + align:start position:0% +so Compton was convinced this could be +made sense of using you know the totally + + align:start position:0% +made sense of using you know the totally + + + align:start position:0% +made sense of using you know the totally +standard by that point maxwellian + + align:start position:0% +standard by that point maxwellian + + + align:start position:0% +standard by that point maxwellian +electromagnetic waves these were high + + align:start position:0% +electromagnetic waves these were high + + + align:start position:0% +electromagnetic waves these were high +frequency maximal waves scattering off + + align:start position:0% +frequency maximal waves scattering off + + + align:start position:0% +frequency maximal waves scattering off +of a certain Target and yet try and try + + align:start position:0% +of a certain Target and yet try and try + + + align:start position:0% +of a certain Target and yet try and try +and try as he might he could not come up + + align:start position:0% +and try as he might he could not come up + + + align:start position:0% +and try as he might he could not come up +with any sensible explanation or + + align:start position:0% +with any sensible explanation or + + + align:start position:0% +with any sensible explanation or +accounting for this empirical + + align:start position:0% +accounting for this empirical + + + align:start position:0% +accounting for this empirical +relationship when he kept finding + + align:start position:0% +relationship when he kept finding + + + align:start position:0% +relationship when he kept finding +conducting the experiment measuring more + + align:start position:0% +conducting the experiment measuring more + + + align:start position:0% +conducting the experiment measuring more +and more carefully the shift in + + align:start position:0% +and more carefully the shift in + + + align:start position:0% +and more carefully the shift in +frequency with uh with the scattered + + align:start position:0% +frequency with uh with the scattered + + + align:start position:0% +frequency with uh with the scattered +angle he couldn't come up with any kind + + align:start position:0% +angle he couldn't come up with any kind + + + align:start position:0% +angle he couldn't come up with any kind +of theoretical explanation that would + + align:start position:0% +of theoretical explanation that would + + + align:start position:0% +of theoretical explanation that would +account for that shift until in yet + + align:start position:0% +account for that shift until in yet + + + align:start position:0% +account for that shift until in yet +another kind of active desperation much + + align:start position:0% +another kind of active desperation much + + + align:start position:0% +another kind of active desperation much +like Mark's Planck he then kind of + + align:start position:0% +like Mark's Planck he then kind of + + + align:start position:0% +like Mark's Planck he then kind of +grudgingly tries on takes on this + + align:start position:0% +grudgingly tries on takes on this + + + align:start position:0% +grudgingly tries on takes on this +einsteinian hypothesis or heuristic + + align:start position:0% +einsteinian hypothesis or heuristic + + + align:start position:0% +einsteinian hypothesis or heuristic +suggestion only when Arthur Compton + + align:start position:0% +suggestion only when Arthur Compton + + + align:start position:0% +suggestion only when Arthur Compton +again kind of grudgingly adopts this + + align:start position:0% +again kind of grudgingly adopts this + + + align:start position:0% +again kind of grudgingly adopts this +suggestion from Albert Einstein to treat + + align:start position:0% +suggestion from Albert Einstein to treat + + + align:start position:0% +suggestion from Albert Einstein to treat +light in this case the very high energy + + align:start position:0% +light in this case the very high energy + + + align:start position:0% +light in this case the very high energy +x-rays as little collections of discrete + + align:start position:0% +x-rays as little collections of discrete + + + align:start position:0% +x-rays as little collections of discrete +particles each with her own discrete + + align:start position:0% +particles each with her own discrete + + + align:start position:0% +particles each with her own discrete +packets of energy rather than as + + align:start position:0% +packets of energy rather than as + + + align:start position:0% +packets of energy rather than as +Maximilian waves only then can he make + + align:start position:0% +Maximilian waves only then can he make + + + align:start position:0% +Maximilian waves only then can he make +sense of this empirical pattern in his + + align:start position:0% +sense of this empirical pattern in his + + + align:start position:0% +sense of this empirical pattern in his +laboratory + + align:start position:0% +laboratory + + + align:start position:0% +laboratory +so here's the diagram from his actual + + align:start position:0% +so here's the diagram from his actual + + + align:start position:0% +so here's the diagram from his actual +published article in the physical view + + align:start position:0% +published article in the physical view + + + align:start position:0% +published article in the physical view +it was submitted in the very closing + + align:start position:0% +it was submitted in the very closing + + + align:start position:0% +it was submitted in the very closing +days of calendar year 1922 was published + + align:start position:0% +days of calendar year 1922 was published + + + align:start position:0% +days of calendar year 1922 was published +on Spring of 23. uh so here's the actual + + align:start position:0% +on Spring of 23. uh so here's the actual + + + align:start position:0% +on Spring of 23. uh so here's the actual +illustration from his article and again + + align:start position:0% +illustration from his article and again + + + align:start position:0% +illustration from his article and again +in the in the accompanying + + align:start position:0% +in the in the accompanying + + + align:start position:0% +in the in the accompanying +um optional lecture notes I go through + + align:start position:0% +um optional lecture notes I go through + + + align:start position:0% +um optional lecture notes I go through +the the the algebra that were slowly so + + align:start position:0% +the the the algebra that were slowly so + + + align:start position:0% +the the the algebra that were slowly so +I'm going to show you where he gets + + align:start position:0% +I'm going to show you where he gets + + + align:start position:0% +I'm going to show you where he gets +don't worry if if some of these steps + + align:start position:0% +don't worry if if some of these steps + + + align:start position:0% +don't worry if if some of these steps +are hard to do in your head they're hard + + align:start position:0% +are hard to do in your head they're hard + + + align:start position:0% +are hard to do in your head they're hard +for me to do in my head take your time + + align:start position:0% +for me to do in my head take your time + + + align:start position:0% +for me to do in my head take your time +if you'd like and go through the the + + align:start position:0% +if you'd like and go through the the + + + align:start position:0% +if you'd like and go through the the +algebra in the notes so what what + + align:start position:0% +algebra in the notes so what what + + + align:start position:0% +algebra in the notes so what what +Compton winds up doing is treating the + + align:start position:0% +Compton winds up doing is treating the + + + align:start position:0% +Compton winds up doing is treating the +interaction between the incoming x-ray + + align:start position:0% +interaction between the incoming x-ray + + + align:start position:0% +interaction between the incoming x-ray +that's what's here we now by the + + align:start position:0% +that's what's here we now by the + + + align:start position:0% +that's what's here we now by the +published version has uh decided to call + + align:start position:0% +published version has uh decided to call + + + align:start position:0% +published version has uh decided to call +this incident light Quantum is already + + align:start position:0% +this incident light Quantum is already + + + align:start position:0% +this incident light Quantum is already +now now you borrowing Einstein's ideas + + align:start position:0% +now now you borrowing Einstein's ideas + + + align:start position:0% +now now you borrowing Einstein's ideas +it's not where we started + + align:start position:0% +it's not where we started + + + align:start position:0% +it's not where we started +pardon me + + align:start position:0% +pardon me + + + align:start position:0% +pardon me +so here's the incoming x-ray + + align:start position:0% +so here's the incoming x-ray + + + align:start position:0% +so here's the incoming x-ray +and how would you characterize + + align:start position:0% +and how would you characterize + + + align:start position:0% +and how would you characterize +the energy or the momentum of that of + + align:start position:0% +the energy or the momentum of that of + + + align:start position:0% +the energy or the momentum of that of +that incoming source of light + + align:start position:0% +that incoming source of light + + + align:start position:0% +that incoming source of light +that's what Compton starts with before + + align:start position:0% +that's what Compton starts with before + + + align:start position:0% +that's what Compton starts with before +Collision + + align:start position:0% + + + + align:start position:0% + +so even + + align:start position:0% +so even + + + align:start position:0% +so even +by Matt using Maxwell's Theory + + align:start position:0% +by Matt using Maxwell's Theory + + + align:start position:0% +by Matt using Maxwell's Theory +people knew they could + + align:start position:0% +people knew they could + + + align:start position:0% +people knew they could +calculate an Associated momentum carried + + align:start position:0% +calculate an Associated momentum carried + + + align:start position:0% +calculate an Associated momentum carried +by a light wave + + align:start position:0% +by a light wave + + + align:start position:0% +by a light wave +is related to things like the pointing + + align:start position:0% +is related to things like the pointing + + + align:start position:0% +is related to things like the pointing +Vector joining it super fancy but + + align:start position:0% +Vector joining it super fancy but + + + align:start position:0% +Vector joining it super fancy but +basically Maxwell's equations suggested + + align:start position:0% +basically Maxwell's equations suggested + + + align:start position:0% +basically Maxwell's equations suggested +the momentum carried by radiation by + + align:start position:0% +the momentum carried by radiation by + + + align:start position:0% +the momentum carried by radiation by +light + + align:start position:0% +light + + + align:start position:0% +light +is equal to the energy carried by that + + align:start position:0% +is equal to the energy carried by that + + + align:start position:0% +is equal to the energy carried by that +light wave divided by its speed that was + + align:start position:0% +light wave divided by its speed that was + + + align:start position:0% +light wave divided by its speed that was +again a kind of classical result even + + align:start position:0% +again a kind of classical result even + + + align:start position:0% +again a kind of classical result even +from wave theory of light and now + + align:start position:0% +from wave theory of light and now + + + align:start position:0% +from wave theory of light and now +confidence starts adding in this new + + align:start position:0% +confidence starts adding in this new + + + align:start position:0% +confidence starts adding in this new +heuristic stuff from Einstein what if + + align:start position:0% +heuristic stuff from Einstein what if + + + align:start position:0% +heuristic stuff from Einstein what if +each individual light quantum + + align:start position:0% +each individual light quantum + + + align:start position:0% +each individual light quantum +and now I'll be a little anachronistic + + align:start position:0% +and now I'll be a little anachronistic + + + align:start position:0% +and now I'll be a little anachronistic +and just use the term Photon that's not + + align:start position:0% +and just use the term Photon that's not + + + align:start position:0% +and just use the term Photon that's not +the term that Compton used it gets + + align:start position:0% +the term that Compton used it gets + + + align:start position:0% +the term that Compton used it gets +introduced soon after competence results + + align:start position:0% +introduced soon after competence results + + + align:start position:0% +introduced soon after competence results +so by the 19 within the 1920s it had + + align:start position:0% +so by the 19 within the 1920s it had + + + align:start position:0% +so by the 19 within the 1920s it had +already become common to use the term + + align:start position:0% +already become common to use the term + + + align:start position:0% +already become common to use the term +Photon as we still do today to describe + + align:start position:0% +Photon as we still do today to describe + + + align:start position:0% +Photon as we still do today to describe +these like + + align:start position:0% +these like + + + align:start position:0% +these like +so now let's take on Einstein's + + align:start position:0% +so now let's take on Einstein's + + + align:start position:0% +so now let's take on Einstein's +suggestion that each individual Photon + + align:start position:0% +suggestion that each individual Photon + + + align:start position:0% +suggestion that each individual Photon +of light carries a quantized amount of + + align:start position:0% +of light carries a quantized amount of + + + align:start position:0% +of light carries a quantized amount of +energy proportional to its frequency + + align:start position:0% +energy proportional to its frequency + + + align:start position:0% +energy proportional to its frequency +then let's use the usual relation for + + align:start position:0% +then let's use the usual relation for + + + align:start position:0% +then let's use the usual relation for +any wave between frequency and + + align:start position:0% +any wave between frequency and + + + align:start position:0% +any wave between frequency and +wavelength with the constant of + + align:start position:0% +wavelength with the constant of + + + align:start position:0% +wavelength with the constant of +proportionality the speed + + align:start position:0% +proportionality the speed + + + align:start position:0% +proportionality the speed +so now you can come back to this sort of + + align:start position:0% +so now you can come back to this sort of + + + align:start position:0% +so now you can come back to this sort of +maxwellian expression for the momentum + + align:start position:0% +maxwellian expression for the momentum + + + align:start position:0% +maxwellian expression for the momentum +carried by a classical light wave kind + + align:start position:0% +carried by a classical light wave kind + + + align:start position:0% +carried by a classical light wave kind +of add in this new einstein-like Quantum + + align:start position:0% +of add in this new einstein-like Quantum + + + align:start position:0% +of add in this new einstein-like Quantum +thing and come up with an expression for + + align:start position:0% +thing and come up with an expression for + + + align:start position:0% +thing and come up with an expression for +the momentum carried by each individual + + align:start position:0% +the momentum carried by each individual + + + align:start position:0% +the momentum carried by each individual +Photon or light Quantum and that would + + align:start position:0% +Photon or light Quantum and that would + + + align:start position:0% +Photon or light Quantum and that would +be the energy + + align:start position:0% +be the energy + + + align:start position:0% +be the energy +divided by its speed H over lamb + + align:start position:0% +divided by its speed H over lamb + + + align:start position:0% +divided by its speed H over lamb +remember that's not where Compton starts + + align:start position:0% +remember that's not where Compton starts + + + align:start position:0% +remember that's not where Compton starts +that's where it gets out of desperation + + align:start position:0% +that's where it gets out of desperation + + + align:start position:0% +that's where it gets out of desperation +so now Compton has an expression for + + align:start position:0% +so now Compton has an expression for + + + align:start position:0% +so now Compton has an expression for +both the momentum and the energy of this + + align:start position:0% +both the momentum and the energy of this + + + align:start position:0% +both the momentum and the energy of this +light Quantum prior to scattering + + align:start position:0% +light Quantum prior to scattering + + + align:start position:0% +light Quantum prior to scattering +he's going to treat this as I say like a + + align:start position:0% +he's going to treat this as I say like a + + + align:start position:0% +he's going to treat this as I say like a +two-body problem as if these were two + + align:start position:0% +two-body problem as if these were two + + + align:start position:0% +two-body problem as if these were two +billiard balls rather than like a wave + + align:start position:0% +billiard balls rather than like a wave + + + align:start position:0% +billiard balls rather than like a wave +scattering off of a little chunk of + + align:start position:0% +scattering off of a little chunk of + + + align:start position:0% +scattering off of a little chunk of +matter + + align:start position:0% +matter + + + align:start position:0% +matter +so prior to the Collision he's going to + + align:start position:0% +so prior to the Collision he's going to + + + align:start position:0% +so prior to the Collision he's going to +say this electron over here this target + + align:start position:0% +say this electron over here this target + + + align:start position:0% +say this electron over here this target +has a little dot here is just sitting + + align:start position:0% +has a little dot here is just sitting + + + align:start position:0% +has a little dot here is just sitting +there at rest it's momentum is zero it + + align:start position:0% +there at rest it's momentum is zero it + + + align:start position:0% +there at rest it's momentum is zero it +has no velocity + + align:start position:0% +has no velocity + + + align:start position:0% +has no velocity +and it has some rest energy MC squared + + align:start position:0% +and it has some rest energy MC squared + + + align:start position:0% +and it has some rest energy MC squared +Remember by 1922 Einstein's work on + + align:start position:0% +Remember by 1922 Einstein's work on + + + align:start position:0% +Remember by 1922 Einstein's work on +relativity was indeed much more better + + align:start position:0% +relativity was indeed much more better + + + align:start position:0% +relativity was indeed much more better +known and uh seemed to have passed a + + align:start position:0% +known and uh seemed to have passed a + + + align:start position:0% +known and uh seemed to have passed a +number of tests so Compton had no qualms + + align:start position:0% +number of tests so Compton had no qualms + + + align:start position:0% +number of tests so Compton had no qualms +about borrowing Isis work on relativity + + align:start position:0% +about borrowing Isis work on relativity + + + align:start position:0% +about borrowing Isis work on relativity +including things like this rest energy + + align:start position:0% +including things like this rest energy + + + align:start position:0% +including things like this rest energy +mc squared even though he was not going + + align:start position:0% +mc squared even though he was not going + + + align:start position:0% +mc squared even though he was not going +into this convinced of the like Quantum + + align:start position:0% +into this convinced of the like Quantum + + + align:start position:0% +into this convinced of the like Quantum +set so now I have the ingredients we + + align:start position:0% +set so now I have the ingredients we + + + align:start position:0% +set so now I have the ingredients we +need to describe the two scattering + + align:start position:0% +need to describe the two scattering + + + align:start position:0% +need to describe the two scattering +billiard balls the two objects prior to + + align:start position:0% +billiard balls the two objects prior to + + + align:start position:0% +billiard balls the two objects prior to +Collision we can characterize the energy + + align:start position:0% +Collision we can characterize the energy + + + align:start position:0% +Collision we can characterize the energy +and momentum of the incoming x-ray as a + + align:start position:0% +and momentum of the incoming x-ray as a + + + align:start position:0% +and momentum of the incoming x-ray as a +collection of discrete palette-like + + align:start position:0% +collection of discrete palette-like + + + align:start position:0% +collection of discrete palette-like +light quanta we have the energy momentum + + align:start position:0% +light quanta we have the energy momentum + + + align:start position:0% +light quanta we have the energy momentum +before Collision of the target is + + align:start position:0% +before Collision of the target is + + + align:start position:0% +before Collision of the target is +electron just sitting still about to get + + align:start position:0% +electron just sitting still about to get + + + align:start position:0% +electron just sitting still about to get +smacked + + align:start position:0% +smacked + + + align:start position:0% +smacked +after the Collision the light Quantum + + align:start position:0% +after the Collision the light Quantum + + + align:start position:0% +after the Collision the light Quantum +gets scattered off at some angle Theta + + align:start position:0% +gets scattered off at some angle Theta + + + align:start position:0% +gets scattered off at some angle Theta +compared to its incoming Direction + + align:start position:0% +compared to its incoming Direction + + + align:start position:0% +compared to its incoming Direction +that's the angle Theta here it now has + + align:start position:0% +that's the angle Theta here it now has + + + align:start position:0% +that's the angle Theta here it now has +in general some different wavelength so + + align:start position:0% +in general some different wavelength so + + + align:start position:0% +in general some different wavelength so +the momentum of that Photon Compton out + + align:start position:0% +the momentum of that Photon Compton out + + + align:start position:0% +the momentum of that Photon Compton out +of taking on Einstein's work is going to + + align:start position:0% +of taking on Einstein's work is going to + + + align:start position:0% +of taking on Einstein's work is going to +be given by some Universal constant that + + align:start position:0% +be given by some Universal constant that + + + align:start position:0% +be given by some Universal constant that +hasn't changed that's just Planck's + + align:start position:0% +hasn't changed that's just Planck's + + + align:start position:0% +hasn't changed that's just Planck's +constant but the wavelength indeed might + + align:start position:0% +constant but the wavelength indeed might + + + align:start position:0% +constant but the wavelength indeed might +have changed in fact he was measuring + + align:start position:0% +have changed in fact he was measuring + + + align:start position:0% +have changed in fact he was measuring +exactly that change in wavelength + + align:start position:0% +exactly that change in wavelength + + + align:start position:0% +exactly that change in wavelength +likewise the energy of photon therefore + + align:start position:0% +likewise the energy of photon therefore + + + align:start position:0% +likewise the energy of photon therefore +will change because it's wavelength will + + align:start position:0% +will change because it's wavelength will + + + align:start position:0% +will change because it's wavelength will +change so he has now an expression for + + align:start position:0% +change so he has now an expression for + + + align:start position:0% +change so he has now an expression for +energy momentum of a light Quantum + + align:start position:0% +energy momentum of a light Quantum + + + align:start position:0% +energy momentum of a light Quantum +following collision and likewise the + + align:start position:0% +following collision and likewise the + + + align:start position:0% +following collision and likewise the +electrons now been smacked by some very + + align:start position:0% +electrons now been smacked by some very + + + align:start position:0% +electrons now been smacked by some very +high energy pellet this high energy + + align:start position:0% +high energy pellet this high energy + + + align:start position:0% +high energy pellet this high energy +light Quantum of the x-rays + + align:start position:0% +light Quantum of the x-rays + + + align:start position:0% +light Quantum of the x-rays +so now it will recoil at some other uh + + align:start position:0% +so now it will recoil at some other uh + + + align:start position:0% +so now it will recoil at some other uh +in some other direction some angle let's + + align:start position:0% +in some other direction some angle let's + + + align:start position:0% +in some other direction some angle let's +call it Phi after getting smacked by the + + align:start position:0% +call it Phi after getting smacked by the + + + align:start position:0% +call it Phi after getting smacked by the +incoming like one so now it has some + + align:start position:0% +incoming like one so now it has some + + + align:start position:0% +incoming like one so now it has some +non-zero momentum in fact if it's a high + + align:start position:0% +non-zero momentum in fact if it's a high + + + align:start position:0% +non-zero momentum in fact if it's a high +enough energy incoming x-ray x-rays are + + align:start position:0% +enough energy incoming x-ray x-rays are + + + align:start position:0% +enough energy incoming x-ray x-rays are +very energetic light waves in general an + + align:start position:0% +very energetic light waves in general an + + + align:start position:0% +very energetic light waves in general an +electron might actually acquire a + + align:start position:0% +electron might actually acquire a + + + align:start position:0% +electron might actually acquire a +relativistic momentum it's it's recoil + + align:start position:0% +relativistic momentum it's it's recoil + + + align:start position:0% +relativistic momentum it's it's recoil +speed could in general be comparable to + + align:start position:0% +speed could in general be comparable to + + + align:start position:0% +speed could in general be comparable to +the speed of light it could get quite a + + align:start position:0% +the speed of light it could get quite a + + + align:start position:0% +the speed of light it could get quite a +Junt from that Collision so again + + align:start position:0% +Junt from that Collision so again + + + align:start position:0% +Junt from that Collision so again +Compton uses by then the standard uh + + align:start position:0% +Compton uses by then the standard uh + + + align:start position:0% +Compton uses by then the standard uh +relativistic Expressions momentum and + + align:start position:0% +relativistic Expressions momentum and + + + align:start position:0% +relativistic Expressions momentum and +likewise for energy and again I have a + + align:start position:0% +likewise for energy and again I have a + + + align:start position:0% +likewise for energy and again I have a +set of lecture notes that were optional + + align:start position:0% +set of lecture notes that were optional + + + align:start position:0% +set of lecture notes that were optional +on the canvas site from when we talked + + align:start position:0% +on the canvas site from when we talked + + + align:start position:0% +on the canvas site from when we talked +about Einstein and relativity to go over + + align:start position:0% +about Einstein and relativity to go over + + + align:start position:0% +about Einstein and relativity to go over +things like E equals MC squared + + align:start position:0% +things like E equals MC squared + + + align:start position:0% +things like E equals MC squared +relativistic momentum and all that so + + align:start position:0% +relativistic momentum and all that so + + + align:start position:0% +relativistic momentum and all that so +you you have a chance to go back to + + align:start position:0% +you you have a chance to go back to + + + align:start position:0% +you you have a chance to go back to +those notes if that's not familiar this + + align:start position:0% +those notes if that's not familiar this + + + align:start position:0% +those notes if that's not familiar this +point just to let us know this for what + + align:start position:0% +point just to let us know this for what + + + align:start position:0% +point just to let us know this for what +we need to know today this stuff was by + + align:start position:0% +we need to know today this stuff was by + + + align:start position:0% +we need to know today this stuff was by +that point kind of standard issue + + align:start position:0% +that point kind of standard issue + + + align:start position:0% +that point kind of standard issue +Compton was doing nothing controversial + + align:start position:0% +Compton was doing nothing controversial + + + align:start position:0% +Compton was doing nothing controversial +here in adopting the relativistic energy + + align:start position:0% +here in adopting the relativistic energy + + + align:start position:0% +here in adopting the relativistic energy +and momentum for the scattered electron + + align:start position:0% +and momentum for the scattered electron + + + align:start position:0% +and momentum for the scattered electron +okay now he does what anyone would do + + align:start position:0% +okay now he does what anyone would do + + + align:start position:0% +okay now he does what anyone would do +when you have two particles colliding + + align:start position:0% +when you have two particles colliding + + + align:start position:0% +when you have two particles colliding +not a wave smacking into the shore but + + align:start position:0% +not a wave smacking into the shore but + + + align:start position:0% +not a wave smacking into the shore but +two discrete little bundles of energy + + align:start position:0% +two discrete little bundles of energy + + + align:start position:0% +two discrete little bundles of energy +that Collide like billiard balls on a + + align:start position:0% +that Collide like billiard balls on a + + + align:start position:0% +that Collide like billiard balls on a +pool table + + align:start position:0% +pool table + + + align:start position:0% +pool table +one thing we have to do in any two body + + align:start position:0% +one thing we have to do in any two body + + + align:start position:0% +one thing we have to do in any two body +collision is conserve energy just as we + + align:start position:0% +collision is conserve energy just as we + + + align:start position:0% +collision is conserve energy just as we +would do uh in ordinary Newtonian + + align:start position:0% +would do uh in ordinary Newtonian + + + align:start position:0% +would do uh in ordinary Newtonian +mechanics so what's the total energy + + align:start position:0% +mechanics so what's the total energy + + + align:start position:0% +mechanics so what's the total energy +coming in uh before Collision the + + align:start position:0% +coming in uh before Collision the + + + align:start position:0% +coming in uh before Collision the +incoming energy of the photon this one + + align:start position:0% +incoming energy of the photon this one + + + align:start position:0% +incoming energy of the photon this one +here the incoming energy electrons just + + align:start position:0% +here the incoming energy electrons just + + + align:start position:0% +here the incoming energy electrons just +its rest mass and that total energy has + + align:start position:0% +its rest mass and that total energy has + + + align:start position:0% +its rest mass and that total energy has +to balance the total energy ecosystem + + align:start position:0% +to balance the total energy ecosystem + + + align:start position:0% +to balance the total energy ecosystem +following Collision so he has his + + align:start position:0% +following Collision so he has his + + + align:start position:0% +following Collision so he has his +corresponding expressions for the energy + + align:start position:0% +corresponding expressions for the energy + + + align:start position:0% +corresponding expressions for the energy +of the photon and the electron following + + align:start position:0% +of the photon and the electron following + + + align:start position:0% +of the photon and the electron following +scattering and we can now fill in from + + align:start position:0% +scattering and we can now fill in from + + + align:start position:0% +scattering and we can now fill in from +this table what those values should be + + align:start position:0% +this table what those values should be + + + align:start position:0% +this table what those values should be +likewise we have to conserve momentum as + + align:start position:0% +likewise we have to conserve momentum as + + + align:start position:0% +likewise we have to conserve momentum as +we all know momentum is a vector + + align:start position:0% +we all know momentum is a vector + + + align:start position:0% +we all know momentum is a vector +quantity so we have to conserve momentum + + align:start position:0% +quantity so we have to conserve momentum + + + align:start position:0% +quantity so we have to conserve momentum +both in the sort of X Direction along + + align:start position:0% +both in the sort of X Direction along + + + align:start position:0% +both in the sort of X Direction along +the original direction of travel for the + + align:start position:0% +the original direction of travel for the + + + align:start position:0% +the original direction of travel for the +incoming uh light Quantum as well as in + + align:start position:0% +incoming uh light Quantum as well as in + + + align:start position:0% +incoming uh light Quantum as well as in +the perpendicular Direction this case + + align:start position:0% +the perpendicular Direction this case + + + align:start position:0% +the perpendicular Direction this case +the Y Direction and so again this is + + align:start position:0% +the Y Direction and so again this is + + + align:start position:0% +the Y Direction and so again this is +done in a bit more detail in the notes + + align:start position:0% +done in a bit more detail in the notes + + + align:start position:0% +done in a bit more detail in the notes +if this uh is hard to kind of parse in + + align:start position:0% +if this uh is hard to kind of parse in + + + align:start position:0% +if this uh is hard to kind of parse in +real time but the upshot is this Compton + + align:start position:0% +real time but the upshot is this Compton + + + align:start position:0% +real time but the upshot is this Compton +is doing completely standard stuff for + + align:start position:0% +is doing completely standard stuff for + + + align:start position:0% +is doing completely standard stuff for +two body scattering once he's done the + + align:start position:0% +two body scattering once he's done the + + + align:start position:0% +two body scattering once he's done the +non-standard thing of treating this + + align:start position:0% +non-standard thing of treating this + + + align:start position:0% +non-standard thing of treating this +light as an incoming pellet or particle + + align:start position:0% +light as an incoming pellet or particle + + + align:start position:0% +light as an incoming pellet or particle +so now what's so great is the Compton + + align:start position:0% +so now what's so great is the Compton + + + align:start position:0% +so now what's so great is the Compton +has three equations for three unknowns + + align:start position:0% +has three equations for three unknowns + + + align:start position:0% +has three equations for three unknowns +which is now Rewritten those expressions + + align:start position:0% +which is now Rewritten those expressions + + + align:start position:0% +which is now Rewritten those expressions +we just had + + align:start position:0% +we just had + + + align:start position:0% +we just had +by treating a problem like ordinary two + + align:start position:0% +by treating a problem like ordinary two + + + align:start position:0% +by treating a problem like ordinary two +bodies scattering between discrete + + align:start position:0% +bodies scattering between discrete + + + align:start position:0% +bodies scattering between discrete +localized particles copper has three + + align:start position:0% +localized particles copper has three + + + align:start position:0% +localized particles copper has three +Expressions conservation of energy + + align:start position:0% +Expressions conservation of energy + + + align:start position:0% +Expressions conservation of energy +conservation momentum in each of the two + + align:start position:0% +conservation momentum in each of the two + + + align:start position:0% +conservation momentum in each of the two +perpendicular directions and he has + + align:start position:0% +perpendicular directions and he has + + + align:start position:0% +perpendicular directions and he has +three unknowns he doesn't know what the + + align:start position:0% +three unknowns he doesn't know what the + + + align:start position:0% +three unknowns he doesn't know what the +scattered wavelength is and he doesn't + + align:start position:0% +scattered wavelength is and he doesn't + + + align:start position:0% +scattered wavelength is and he doesn't +know what the angles of scatter are + + align:start position:0% +know what the angles of scatter are + + + align:start position:0% +know what the angles of scatter are +either the angle Theta for the light + + align:start position:0% +either the angle Theta for the light + + + align:start position:0% +either the angle Theta for the light +Quantum or the angle Phi for the + + align:start position:0% +Quantum or the angle Phi for the + + + align:start position:0% +Quantum or the angle Phi for the +recoiling electron so as now it's just + + align:start position:0% +recoiling electron so as now it's just + + + align:start position:0% +recoiling electron so as now it's just +algebra he has three equations for three + + align:start position:0% +algebra he has three equations for three + + + align:start position:0% +algebra he has three equations for three +unknowns and as you'll see in the notes + + align:start position:0% +unknowns and as you'll see in the notes + + + align:start position:0% +unknowns and as you'll see in the notes +uh now it's really just a short number + + align:start position:0% +uh now it's really just a short number + + + align:start position:0% +uh now it's really just a short number +of steps to do to relate the the change + + align:start position:0% +of steps to do to relate the the change + + + align:start position:0% +of steps to do to relate the the change +in wavelength the the Lambda Prime + + align:start position:0% +in wavelength the the Lambda Prime + + + align:start position:0% +in wavelength the the Lambda Prime +following scattering compare that to the + + align:start position:0% +following scattering compare that to the + + + align:start position:0% +following scattering compare that to the +incoming wavelength which you can + + align:start position:0% +incoming wavelength which you can + + + align:start position:0% +incoming wavelength which you can +control he controls the X-ray source + + align:start position:0% +control he controls the X-ray source + + + align:start position:0% +control he controls the X-ray source +and it and it gets related in an + + align:start position:0% +and it and it gets related in an + + + align:start position:0% +and it and it gets related in an +automatic way to that scattering angle + + align:start position:0% +automatic way to that scattering angle + + + align:start position:0% +automatic way to that scattering angle +and exactly the form that content had + + align:start position:0% +and exactly the form that content had + + + align:start position:0% +and exactly the form that content had +been finding empirically not only does + + align:start position:0% +been finding empirically not only does + + + align:start position:0% +been finding empirically not only does +it get the angular dependence correct or + + align:start position:0% +it get the angular dependence correct or + + + align:start position:0% +it get the angular dependence correct or +at least matches his his uh empirical + + align:start position:0% +at least matches his his uh empirical + + + align:start position:0% +at least matches his his uh empirical +results he actually even finds a + + align:start position:0% +results he actually even finds a + + + align:start position:0% +results he actually even finds a +quantitative shift is coefficient the + + align:start position:0% +quantitative shift is coefficient the + + + align:start position:0% +quantitative shift is coefficient the +amount by which the wavelength should + + align:start position:0% +amount by which the wavelength should + + + align:start position:0% +amount by which the wavelength should +shift is now fixed by these Universal + + align:start position:0% +shift is now fixed by these Universal + + + align:start position:0% +shift is now fixed by these Universal +constants Planck's constant the mass of + + align:start position:0% +constants Planck's constant the mass of + + + align:start position:0% +constants Planck's constant the mass of +the electron that Target and the speed + + align:start position:0% +the electron that Target and the speed + + + align:start position:0% +the electron that Target and the speed +of light + + align:start position:0% +of light + + + align:start position:0% +of light +and so competent is treating light-like + + align:start position:0% +and so competent is treating light-like + + + align:start position:0% +and so competent is treating light-like +particles and he's measuring changes in + + align:start position:0% +particles and he's measuring changes in + + + align:start position:0% +particles and he's measuring changes in +a wave like just just going back to + + align:start position:0% +a wave like just just going back to + + + align:start position:0% +a wave like just just going back to +Gary's point from a few moments ago + + align:start position:0% +Gary's point from a few moments ago + + + align:start position:0% +Gary's point from a few moments ago +Compton is now finding further kind of + + align:start position:0% +Compton is now finding further kind of + + + align:start position:0% +Compton is now finding further kind of +examples where kind of half the time he + + align:start position:0% +examples where kind of half the time he + + + align:start position:0% +examples where kind of half the time he +has to pretend that light is just a wave + + align:start position:0% +has to pretend that light is just a wave + + + align:start position:0% +has to pretend that light is just a wave +because he's measuring wave-like + + align:start position:0% +because he's measuring wave-like + + + align:start position:0% +because he's measuring wave-like +properties like wavelength is sort of + + align:start position:0% +properties like wavelength is sort of + + + align:start position:0% +properties like wavelength is sort of +necessarily a wave-like property is the + + align:start position:0% +necessarily a wave-like property is the + + + align:start position:0% +necessarily a wave-like property is the +distance between crests of a wave after + + align:start position:0% +distance between crests of a wave after + + + align:start position:0% +distance between crests of a wave after +all + + align:start position:0% +all + + + align:start position:0% +all +that's what he's controlling and + + align:start position:0% +that's what he's controlling and + + + align:start position:0% +that's what he's controlling and +measuring that's that's his empirical + + align:start position:0% +measuring that's that's his empirical + + + align:start position:0% +measuring that's that's his empirical +input is a wave-like quantity shift in + + align:start position:0% +input is a wave-like quantity shift in + + + align:start position:0% +input is a wave-like quantity shift in +wavelength and yet he's accounting for + + align:start position:0% +wavelength and yet he's accounting for + + + align:start position:0% +wavelength and yet he's accounting for +that uh by talking about a kind of + + align:start position:0% +that uh by talking about a kind of + + + align:start position:0% +that uh by talking about a kind of +discrete particle scattering off another + + align:start position:0% +discrete particle scattering off another + + + align:start position:0% +discrete particle scattering off another +discrete particle uh and so this becomes + + align:start position:0% +discrete particle uh and so this becomes + + + align:start position:0% +discrete particle uh and so this becomes +known as the Compton wave of length this + + align:start position:0% +known as the Compton wave of length this + + + align:start position:0% +known as the Compton wave of length this +combination of fundamental constants + + align:start position:0% +combination of fundamental constants + + + align:start position:0% +combination of fundamental constants +that tells us how much the wavelength of + + align:start position:0% +that tells us how much the wavelength of + + + align:start position:0% +that tells us how much the wavelength of +the scattered light should shift as when + + align:start position:0% +the scattered light should shift as when + + + align:start position:0% +the scattered light should shift as when +changes the angle what's the overall + + align:start position:0% +changes the angle what's the overall + + + align:start position:0% +changes the angle what's the overall +scale by which this wave in this should + + align:start position:0% +scale by which this wave in this should + + + align:start position:0% +scale by which this wave in this should +shift + + align:start position:0% +shift + + + align:start position:0% +shift +and so this becomes a kind of yet + + align:start position:0% +and so this becomes a kind of yet + + + align:start position:0% +and so this becomes a kind of yet +another + + align:start position:0% +another + + + align:start position:0% +another +um hybrid or blend of particle-like and + + align:start position:0% +um hybrid or blend of particle-like and + + + align:start position:0% +um hybrid or blend of particle-like and +wave-like ways of reasoning about light + + align:start position:0% +wave-like ways of reasoning about light + + + align:start position:0% +wave-like ways of reasoning about light +as I mentioned I think in in the lecture + + align:start position:0% +as I mentioned I think in in the lecture + + + align:start position:0% +as I mentioned I think in in the lecture +notes for today this work much like + + align:start position:0% +notes for today this work much like + + + align:start position:0% +notes for today this work much like +Philip Leonards was immediately greeted + + align:start position:0% +Philip Leonards was immediately greeted + + + align:start position:0% +Philip Leonards was immediately greeted +uh as very important uh Compton received + + align:start position:0% +uh as very important uh Compton received + + + align:start position:0% +uh as very important uh Compton received +a Nobel Prize I think by 1927. the paper + + align:start position:0% +a Nobel Prize I think by 1927. the paper + + + align:start position:0% +a Nobel Prize I think by 1927. the paper +was published in the spring of 1923. so + + align:start position:0% +was published in the spring of 1923. so + + + align:start position:0% +was published in the spring of 1923. so +much like with Leonard's work + + align:start position:0% +much like with Leonard's work + + + align:start position:0% +much like with Leonard's work +just a handful of years past between the + + align:start position:0% +just a handful of years past between the + + + align:start position:0% +just a handful of years past between the +very first publication of these + + align:start position:0% +very first publication of these + + + align:start position:0% +very first publication of these +experimental results and the work being + + align:start position:0% +experimental results and the work being + + + align:start position:0% +experimental results and the work being +honored with the Nobel Prize so people + + align:start position:0% +honored with the Nobel Prize so people + + + align:start position:0% +honored with the Nobel Prize so people +were paying attention to Compton's work + + align:start position:0% +were paying attention to Compton's work + + + align:start position:0% +were paying attention to Compton's work +very closely very carefully in real time + + align:start position:0% +very closely very carefully in real time + + + align:start position:0% +very closely very carefully in real time +it was this kind of work that began to + + align:start position:0% +it was this kind of work that began to + + + align:start position:0% +it was this kind of work that began to +convince even the remaining Skeptics uh + + align:start position:0% +convince even the remaining Skeptics uh + + + align:start position:0% +convince even the remaining Skeptics uh +that Einstein's heuristic suggestion + + align:start position:0% +that Einstein's heuristic suggestion + + + align:start position:0% +that Einstein's heuristic suggestion +that like should be treated at least in + + align:start position:0% +that like should be treated at least in + + + align:start position:0% +that like should be treated at least in +some aspects like a collection of + + align:start position:0% +some aspects like a collection of + + + align:start position:0% +some aspects like a collection of +particles that finally begins to gel and + + align:start position:0% +particles that finally begins to gel and + + + align:start position:0% +particles that finally begins to gel and +Achieve something like Community + + align:start position:0% +Achieve something like Community + + + align:start position:0% +Achieve something like Community +agreement whereas in Einstein's earlier + + align:start position:0% +agreement whereas in Einstein's earlier + + + align:start position:0% +agreement whereas in Einstein's earlier +Expressions that had been lacked okay + + align:start position:0% +Expressions that had been lacked okay + + + align:start position:0% +Expressions that had been lacked okay +let me sum + + align:start position:0% +let me sum + + + align:start position:0% +let me sum +and we'll have some more questions + + align:start position:0% +and we'll have some more questions + + + align:start position:0% +and we'll have some more questions +so these three moments in what became is + + align:start position:0% +so these three moments in what became is + + + align:start position:0% +so these three moments in what became is +known as old quantum theory each moment + + align:start position:0% +known as old quantum theory each moment + + + align:start position:0% +known as old quantum theory each moment +of physicists grappling with the nature + + align:start position:0% +of physicists grappling with the nature + + + align:start position:0% +of physicists grappling with the nature +of light + + align:start position:0% +of light + + + align:start position:0% +of light +I remember it's not happening kind of in + + align:start position:0% +I remember it's not happening kind of in + + + align:start position:0% +I remember it's not happening kind of in +a vacuum to begin to understand why + + align:start position:0% +a vacuum to begin to understand why + + + align:start position:0% +a vacuum to begin to understand why +anyone cared at all let alone invested + + align:start position:0% +anyone cared at all let alone invested + + + align:start position:0% +anyone cared at all let alone invested +with such priority in these particular + + align:start position:0% +with such priority in these particular + + + align:start position:0% +with such priority in these particular +experiments uh that really does go back + + align:start position:0% +experiments uh that really does go back + + + align:start position:0% +experiments uh that really does go back +to kind of larger framing of a newly + + align:start position:0% +to kind of larger framing of a newly + + + align:start position:0% +to kind of larger framing of a newly +independent country of Germany uh + + align:start position:0% +independent country of Germany uh + + + align:start position:0% +independent country of Germany uh +Decisions by its leadership to invest in + + align:start position:0% +Decisions by its leadership to invest in + + + align:start position:0% +Decisions by its leadership to invest in +industrialization to make new kinds of + + align:start position:0% +industrialization to make new kinds of + + + align:start position:0% +industrialization to make new kinds of +places like the PTR and so on it's + + align:start position:0% +places like the PTR and so on it's + + + align:start position:0% +places like the PTR and so on it's +within those spaces for specific kind of + + align:start position:0% +within those spaces for specific kind of + + + align:start position:0% +within those spaces for specific kind of +industrial uh applications like electric + + align:start position:0% +industrial uh applications like electric + + + align:start position:0% +industrial uh applications like electric +street lighting that they were really + + align:start position:0% +street lighting that they were really + + + align:start position:0% +street lighting that they were really +committed to studying things like black + + align:start position:0% +committed to studying things like black + + + align:start position:0% +committed to studying things like black +body radiation uh and what it might + + align:start position:0% +body radiation uh and what it might + + + align:start position:0% +body radiation uh and what it might +reveal about Universal properties of + + align:start position:0% +reveal about Universal properties of + + + align:start position:0% +reveal about Universal properties of +light and matter + + align:start position:0% +light and matter + + + align:start position:0% +light and matter +box Planck had just moved to Berlin uh + + align:start position:0% +box Planck had just moved to Berlin uh + + + align:start position:0% +box Planck had just moved to Berlin uh +as this full professor of theoretical + + align:start position:0% +as this full professor of theoretical + + + align:start position:0% +as this full professor of theoretical +physics do a pretty rare job to hold + + align:start position:0% +physics do a pretty rare job to hold + + + align:start position:0% +physics do a pretty rare job to hold +within any German University he was + + align:start position:0% +within any German University he was + + + align:start position:0% +within any German University he was +close by to PTR and he was getting + + align:start position:0% +close by to PTR and he was getting + + + align:start position:0% +close by to PTR and he was getting +updates from his colleagues sometimes + + align:start position:0% +updates from his colleagues sometimes + + + align:start position:0% +updates from his colleagues sometimes +day by day with their increasingly + + align:start position:0% +day by day with their increasingly + + + align:start position:0% +day by day with their increasingly +precise measurements of that Spectrum + + align:start position:0% +precise measurements of that Spectrum + + + align:start position:0% +precise measurements of that Spectrum +the pattern of radiation emitted when + + align:start position:0% +the pattern of radiation emitted when + + + align:start position:0% +the pattern of radiation emitted when +you heat up any material to a + + align:start position:0% +you heat up any material to a + + + align:start position:0% +you heat up any material to a +sufficiently high temperature no matter + + align:start position:0% +sufficiently high temperature no matter + + + align:start position:0% +sufficiently high temperature no matter +how he got there by the end of December + + align:start position:0% +how he got there by the end of December + + + align:start position:0% +how he got there by the end of December +plant could introduced this now uh now + + align:start position:0% +plant could introduced this now uh now + + + align:start position:0% +plant could introduced this now uh now +famous expression for the uh spectral + + align:start position:0% +famous expression for the uh spectral + + + align:start position:0% +famous expression for the uh spectral +energy density to get there he had + + align:start position:0% +energy density to get there he had + + + align:start position:0% +energy density to get there he had +introduced this new constant of nature I + + align:start position:0% +introduced this new constant of nature I + + + align:start position:0% +introduced this new constant of nature I +mean I'll call it plugs constant very + + align:start position:0% +mean I'll call it plugs constant very + + + align:start position:0% +mean I'll call it plugs constant very +very tiny in human scales and yet not + + align:start position:0% +very tiny in human scales and yet not + + + align:start position:0% +very tiny in human scales and yet not +zero and then we saw that whatever + + align:start position:0% +zero and then we saw that whatever + + + align:start position:0% +zero and then we saw that whatever +Planck thought that meant within a few + + align:start position:0% +Planck thought that meant within a few + + + align:start position:0% +Planck thought that meant within a few +years Einstein takes that up + + align:start position:0% +years Einstein takes that up + + + align:start position:0% +years Einstein takes that up +in a sense treats it more seriously than + + align:start position:0% +in a sense treats it more seriously than + + + align:start position:0% +in a sense treats it more seriously than +Planck himself had even done so Einstein + + align:start position:0% +Planck himself had even done so Einstein + + + align:start position:0% +Planck himself had even done so Einstein +not only redrives plant's result from a + + align:start position:0% +not only redrives plant's result from a + + + align:start position:0% +not only redrives plant's result from a +very specific conceptual starting point + + align:start position:0% +very specific conceptual starting point + + + align:start position:0% +very specific conceptual starting point +what if light consists of collections of + + align:start position:0% +what if light consists of collections of + + + align:start position:0% +what if light consists of collections of +discrete quanta soon to be called + + align:start position:0% +discrete quanta soon to be called + + + align:start position:0% +discrete quanta soon to be called +photons and that same uh kind of New + + align:start position:0% +photons and that same uh kind of New + + + align:start position:0% +photons and that same uh kind of New +Concept new new set of ideas uh helps + + align:start position:0% +Concept new new set of ideas uh helps + + + align:start position:0% +Concept new new set of ideas uh helps +Einstein make sense of experiments like + + align:start position:0% +Einstein make sense of experiments like + + + align:start position:0% +Einstein make sense of experiments like +Leonards on the photoelectric effect + + align:start position:0% +Leonards on the photoelectric effect + + + align:start position:0% +Leonards on the photoelectric effect +however as I've emphasized many times + + align:start position:0% +however as I've emphasized many times + + + align:start position:0% +however as I've emphasized many times +that seemed to be compelling to Einstein + + align:start position:0% +that seemed to be compelling to Einstein + + + align:start position:0% +that seemed to be compelling to Einstein +in 1905 but to very few others for years + + align:start position:0% +in 1905 but to very few others for years + + + align:start position:0% +in 1905 but to very few others for years +and years later and they really took the + + align:start position:0% +and years later and they really took the + + + align:start position:0% +and years later and they really took the +better part of two decades until + + align:start position:0% +better part of two decades until + + + align:start position:0% +better part of two decades until +consensus began to converge around this + + align:start position:0% +consensus began to converge around this + + + align:start position:0% +consensus began to converge around this +idea of light quanta or photons a very + + align:start position:0% +idea of light quanta or photons a very + + + align:start position:0% +idea of light quanta or photons a very +important piece of that was these new + + align:start position:0% +important piece of that was these new + + + align:start position:0% +important piece of that was these new +set of experiments by Arthur Compton at + + align:start position:0% +set of experiments by Arthur Compton at + + + align:start position:0% +set of experiments by Arthur Compton at +Chicago + + align:start position:0% +Chicago + + + align:start position:0% +Chicago +where you can only make sense of his of + + align:start position:0% +where you can only make sense of his of + + + align:start position:0% +where you can only make sense of his of +his own new results like doing this kind + + align:start position:0% +his own new results like doing this kind + + + align:start position:0% +his own new results like doing this kind +of dance by talking about uh x-rays as + + align:start position:0% +of dance by talking about uh x-rays as + + + align:start position:0% +of dance by talking about uh x-rays as +waves with wavelengths and then + + align:start position:0% +waves with wavelengths and then + + + align:start position:0% +waves with wavelengths and then +accounting for the shift of those + + align:start position:0% +accounting for the shift of those + + + align:start position:0% +accounting for the shift of those +wave-like properties uh in terms of the + + align:start position:0% +wave-like properties uh in terms of the + + + align:start position:0% +wave-like properties uh in terms of the +particulate or quantum-like scattering + + align:start position:0% +particulate or quantum-like scattering + + + align:start position:0% +particulate or quantum-like scattering +of discrete bodies so I'll stop there we + + align:start position:0% +of discrete bodies so I'll stop there we + + + align:start position:0% +of discrete bodies so I'll stop there we +got time for some more questions and + + align:start position:0% +got time for some more questions and + + + align:start position:0% +got time for some more questions and +discussion + + align:start position:0% +discussion + + + align:start position:0% +discussion +so uh let's see Stanley writes is there + + align:start position:0% +so uh let's see Stanley writes is there + + + align:start position:0% +so uh let's see Stanley writes is there +a reason Compton was able to measure + + align:start position:0% +a reason Compton was able to measure + + + align:start position:0% +a reason Compton was able to measure +enter was this able to assume energy was + + align:start position:0% +enter was this able to assume energy was + + + align:start position:0% +enter was this able to assume energy was +conserved oh very good + + align:start position:0% +conserved oh very good + + + align:start position:0% +conserved oh very good +how do you know energy was not lost in a + + align:start position:0% +how do you know energy was not lost in a + + + align:start position:0% +how do you know energy was not lost in a +sense that was actually an assumption + + align:start position:0% +sense that was actually an assumption + + + align:start position:0% +sense that was actually an assumption +Stanley it's an excellent question + + align:start position:0% +Stanley it's an excellent question + + + align:start position:0% +Stanley it's an excellent question +and in fact it's a very powerful + + align:start position:0% +and in fact it's a very powerful + + + align:start position:0% +and in fact it's a very powerful +question because around the same time + + align:start position:0% +question because around the same time + + + align:start position:0% +question because around the same time +other leading figures like Niels Bohr + + align:start position:0% +other leading figures like Niels Bohr + + + align:start position:0% +other leading figures like Niels Bohr +himself almost exactly the same time + + align:start position:0% +himself almost exactly the same time + + + align:start position:0% +himself almost exactly the same time +right by 1923 and 24 in fact + + align:start position:0% +right by 1923 and 24 in fact + + + align:start position:0% +right by 1923 and 24 in fact +Neil's boring responding to other kind + + align:start position:0% +Neil's boring responding to other kind + + + align:start position:0% +Neil's boring responding to other kind +of curious features of recent results + + align:start position:0% +of curious features of recent results + + + align:start position:0% +of curious features of recent results +suggested that that maybe uh energy is + + align:start position:0% +suggested that that maybe uh energy is + + + align:start position:0% +suggested that that maybe uh energy is +not conserved at the scale of atoms and + + align:start position:0% +not conserved at the scale of atoms and + + + align:start position:0% +not conserved at the scale of atoms and +parts of atoms competent didn't go that + + align:start position:0% +parts of atoms competent didn't go that + + + align:start position:0% +parts of atoms competent didn't go that +far and most of his colleagues never + + align:start position:0% +far and most of his colleagues never + + + align:start position:0% +far and most of his colleagues never +went so far even board switched back and + + align:start position:0% +went so far even board switched back and + + + align:start position:0% +went so far even board switched back and +said nope energies have been considered + + align:start position:0% +said nope energies have been considered + + + align:start position:0% +said nope energies have been considered +so Compton was basically taking on board + + align:start position:0% +so Compton was basically taking on board + + + align:start position:0% +so Compton was basically taking on board +the Assumption just an assumption that + + align:start position:0% +the Assumption just an assumption that + + + align:start position:0% +the Assumption just an assumption that +energy is is conserved always even at + + align:start position:0% +energy is is conserved always even at + + + align:start position:0% +energy is is conserved always even at +the atomic scale that was not proven + + align:start position:0% +the atomic scale that was not proven + + + align:start position:0% +the atomic scale that was not proven +that was an assumption what company was + + align:start position:0% +that was an assumption what company was + + + align:start position:0% +that was an assumption what company was +trying to do was basically make as few + + align:start position:0% +trying to do was basically make as few + + + align:start position:0% +trying to do was basically make as few +changes as needed to a kind of + + align:start position:0% +changes as needed to a kind of + + + align:start position:0% +changes as needed to a kind of +straightforward way of analyzing the + + align:start position:0% +straightforward way of analyzing the + + + align:start position:0% +straightforward way of analyzing the +scattering data how would we how would + + align:start position:0% +scattering data how would we how would + + + align:start position:0% +scattering data how would we how would +any of us analyze say the Collision of + + align:start position:0% +any of us analyze say the Collision of + + + align:start position:0% +any of us analyze say the Collision of +two you know of two balls um on human + + align:start position:0% +two you know of two balls um on human + + + align:start position:0% +two you know of two balls um on human +scales to a billion balls of baseball + + align:start position:0% +scales to a billion balls of baseball + + + align:start position:0% +scales to a billion balls of baseball +and a baseball bat any of these things + + align:start position:0% +and a baseball bat any of these things + + + align:start position:0% +and a baseball bat any of these things +we would assume energy is conserved we + + align:start position:0% +we would assume energy is conserved we + + + align:start position:0% +we would assume energy is conserved we +would assume momentum is conserved in + + align:start position:0% +would assume momentum is conserved in + + + align:start position:0% +would assume momentum is conserved in +each of its relevance + + align:start position:0% +each of its relevance + + + align:start position:0% +each of its relevance +components and that's what Compton's + + align:start position:0% +components and that's what Compton's + + + align:start position:0% +components and that's what Compton's +doing and that was actually what most + + align:start position:0% +doing and that was actually what most + + + align:start position:0% +doing and that was actually what most +physicists continue to do although + + align:start position:0% +physicists continue to do although + + + align:start position:0% +physicists continue to do although +you're quite right to point out Stanley + + align:start position:0% +you're quite right to point out Stanley + + + align:start position:0% +you're quite right to point out Stanley +that really was an assumption it wasn't + + align:start position:0% +that really was an assumption it wasn't + + + align:start position:0% +that really was an assumption it wasn't +um written in stone it wasn't guaranteed + + align:start position:0% +um written in stone it wasn't guaranteed + + + align:start position:0% +um written in stone it wasn't guaranteed +nowadays we look back we have tons and + + align:start position:0% +nowadays we look back we have tons and + + + align:start position:0% +nowadays we look back we have tons and +tons of reasons to think that energy + + align:start position:0% +tons of reasons to think that energy + + + align:start position:0% +tons of reasons to think that energy +really is conserved even at the atomic + + align:start position:0% +really is conserved even at the atomic + + + align:start position:0% +really is conserved even at the atomic +scale even when we think about light + + align:start position:0% +scale even when we think about light + + + align:start position:0% +scale even when we think about light +quanta that was by no means uh um sort + + align:start position:0% +quanta that was by no means uh um sort + + + align:start position:0% +quanta that was by no means uh um sort +of hard and fast uh evidence at the time + + align:start position:0% +of hard and fast uh evidence at the time + + + align:start position:0% +of hard and fast uh evidence at the time +Compton assumed it and that helped him + + align:start position:0% +Compton assumed it and that helped him + + + align:start position:0% +Compton assumed it and that helped him +get the results that he otherwise was + + align:start position:0% +get the results that he otherwise was + + + align:start position:0% +get the results that he otherwise was +aiming to explain + + align:start position:0% +aiming to explain + + + align:start position:0% +aiming to explain +excellent question Obi asks it's + + align:start position:0% +excellent question Obi asks it's + + + align:start position:0% +excellent question Obi asks it's +interesting that Einstein acceptance + + align:start position:0% +interesting that Einstein acceptance + + + align:start position:0% +interesting that Einstein acceptance +Duality because then he rejected The + + align:start position:0% +Duality because then he rejected The + + + align:start position:0% +Duality because then he rejected The +Ether before because it required + + align:start position:0% +Ether before because it required + + + align:start position:0% +Ether before because it required +conflicting explanations oh we I agree + + align:start position:0% +conflicting explanations oh we I agree + + + align:start position:0% +conflicting explanations oh we I agree +that's an excellent point actually + + align:start position:0% +that's an excellent point actually + + + align:start position:0% +that's an excellent point actually +you're totally right so what one might + + align:start position:0% +you're totally right so what one might + + + align:start position:0% +you're totally right so what one might +have expected Einstein to say the + + align:start position:0% +have expected Einstein to say the + + + align:start position:0% +have expected Einstein to say the +Assumption of Maximilian waves is merely + + align:start position:0% +Assumption of Maximilian waves is merely + + + align:start position:0% +Assumption of Maximilian waves is merely +Superfluous right there's the same + + align:start position:0% +Superfluous right there's the same + + + align:start position:0% +Superfluous right there's the same +language you use about The Ether + + align:start position:0% + + + + align:start position:0% + +I wondered got me back to Gary's point + + align:start position:0% +I wondered got me back to Gary's point + + + align:start position:0% +I wondered got me back to Gary's point +from earlier I wonder + + align:start position:0% +from earlier I wonder + + + align:start position:0% +from earlier I wonder +if Einstein didn't make that move here + + align:start position:0% +if Einstein didn't make that move here + + + align:start position:0% +if Einstein didn't make that move here +because he himself knew that there were + + align:start position:0% +because he himself knew that there were + + + align:start position:0% +because he himself knew that there were +things that he thought wave-like + + align:start position:0% +things that he thought wave-like + + + align:start position:0% +things that he thought wave-like +properties really could explain I think + + align:start position:0% +properties really could explain I think + + + align:start position:0% +properties really could explain I think +Einstein had convinced himself by 1905 + + align:start position:0% +Einstein had convinced himself by 1905 + + + align:start position:0% +Einstein had convinced himself by 1905 +that invoking The luminiferous Ether + + align:start position:0% +that invoking The luminiferous Ether + + + align:start position:0% +that invoking The luminiferous Ether +didn't help people understand anything + + align:start position:0% +didn't help people understand anything + + + align:start position:0% +didn't help people understand anything +that it was meant to explain that the + + align:start position:0% +that it was meant to explain that the + + + align:start position:0% +that it was meant to explain that the +easiest meant to explain + + align:start position:0% +easiest meant to explain + + + align:start position:0% +easiest meant to explain +thinking about lightest waves still had + + align:start position:0% +thinking about lightest waves still had + + + align:start position:0% +thinking about lightest waves still had +explanatory power for things like + + align:start position:0% +explanatory power for things like + + + align:start position:0% +explanatory power for things like +interference diffraction refraction so I + + align:start position:0% +interference diffraction refraction so I + + + align:start position:0% +interference diffraction refraction so I +think he he was I'm assuming we can go + + align:start position:0% +think he he was I'm assuming we can go + + + align:start position:0% +think he he was I'm assuming we can go +back and look more and other Scholars + + align:start position:0% +back and look more and other Scholars + + + align:start position:0% +back and look more and other Scholars +look more carefully this + + align:start position:0% +look more carefully this + + + align:start position:0% +look more carefully this +my assumption is that Einstein didn't + + align:start position:0% +my assumption is that Einstein didn't + + + align:start position:0% +my assumption is that Einstein didn't +want to give up on waves as as never + + align:start position:0% +want to give up on waves as as never + + + align:start position:0% +want to give up on waves as as never +being helpful to think about light + + align:start position:0% +being helpful to think about light + + + align:start position:0% +being helpful to think about light +because of this body of evidence that he + + align:start position:0% +because of this body of evidence that he + + + align:start position:0% +because of this body of evidence that he +thought really could be for which a wave + + align:start position:0% +thought really could be for which a wave + + + align:start position:0% +thought really could be for which a wave +explanation was actually helpful + + align:start position:0% +explanation was actually helpful + + + align:start position:0% +explanation was actually helpful +whereas he had convinced himself partly + + align:start position:0% +whereas he had convinced himself partly + + + align:start position:0% +whereas he had convinced himself partly +from his reading Advanced Mock and so + + align:start position:0% +from his reading Advanced Mock and so + + + align:start position:0% +from his reading Advanced Mock and so +I'm that invoking an ether seems never + + align:start position:0% +I'm that invoking an ether seems never + + + align:start position:0% +I'm that invoking an ether seems never +to be helpful right wave-like behaviors + + align:start position:0% +to be helpful right wave-like behaviors + + + align:start position:0% +to be helpful right wave-like behaviors +there were all kinds of phenomena even + + align:start position:0% +there were all kinds of phenomena even + + + align:start position:0% +there were all kinds of phenomena even +in casual daily experience in Precision + + align:start position:0% +in casual daily experience in Precision + + + align:start position:0% +in casual daily experience in Precision +experiments where things like + + align:start position:0% +experiments where things like + + + align:start position:0% +experiments where things like +interference fringes and so on were + + align:start position:0% +interference fringes and so on were + + + align:start position:0% +interference fringes and so on were +essential + + align:start position:0% +essential + + + align:start position:0% +essential +that's my guess Roy Einstein um kind of + + align:start position:0% +that's my guess Roy Einstein um kind of + + + align:start position:0% +that's my guess Roy Einstein um kind of +called this heuristic didn't announce + + align:start position:0% +called this heuristic didn't announce + + + align:start position:0% +called this heuristic didn't announce +that you know notion everything about + + align:start position:0% +that you know notion everything about + + + align:start position:0% +that you know notion everything about +light waves again and again Einstein + + align:start position:0% +light waves again and again Einstein + + + align:start position:0% +light waves again and again Einstein +becomes one of the most kind of um + + align:start position:0% +becomes one of the most kind of um + + + align:start position:0% +becomes one of the most kind of um +frankly Fearless One of the most + + align:start position:0% +frankly Fearless One of the most + + + align:start position:0% +frankly Fearless One of the most +conceptually daring to say + + align:start position:0% +conceptually daring to say + + + align:start position:0% +conceptually daring to say +um and really trying to pursue this way + + align:start position:0% +um and really trying to pursue this way + + + align:start position:0% +um and really trying to pursue this way +of particle duality over the next kind + + align:start position:0% +of particle duality over the next kind + + + align:start position:0% +of particle duality over the next kind +of two decades he really kind of sits + + align:start position:0% +of two decades he really kind of sits + + + align:start position:0% +of two decades he really kind of sits +with it he doesn't say oh this hurts my + + align:start position:0% +with it he doesn't say oh this hurts my + + + align:start position:0% +with it he doesn't say oh this hurts my +head it must be one or the other he + + align:start position:0% +head it must be one or the other he + + + align:start position:0% +head it must be one or the other he +actually digs in actually + + align:start position:0% +actually digs in actually + + + align:start position:0% +actually digs in actually +uh in a series of developments + + align:start position:0% +uh in a series of developments + + + align:start position:0% +uh in a series of developments +throughout what becomes known as as + + align:start position:0% +throughout what becomes known as as + + + align:start position:0% +throughout what becomes known as as +quantum mechanics so he really found + + align:start position:0% +quantum mechanics so he really found + + + align:start position:0% +quantum mechanics so he really found +this kind of delicious and enticing + + align:start position:0% +this kind of delicious and enticing + + + align:start position:0% +this kind of delicious and enticing +maybe those are the wrong words to use + + align:start position:0% +maybe those are the wrong words to use + + + align:start position:0% +maybe those are the wrong words to use +but he certainly found it worth sitting + + align:start position:0% +but he certainly found it worth sitting + + + align:start position:0% +but he certainly found it worth sitting +with as opposed to it must be a or b + + align:start position:0% +with as opposed to it must be a or b + + + align:start position:0% +with as opposed to it must be a or b +um and we'll see some examples of that + + align:start position:0% +um and we'll see some examples of that + + + align:start position:0% +um and we'll see some examples of that +again in the coming class sessions + + align:start position:0% +again in the coming class sessions + + + align:start position:0% +again in the coming class sessions +excellent observation though any other + + align:start position:0% +excellent observation though any other + + + align:start position:0% +excellent observation though any other +questions + + align:start position:0% + + + + align:start position:0% + +since I have three minutes I'll share + + align:start position:0% +since I have three minutes I'll share + + + align:start position:0% +since I have three minutes I'll share +the following uh one of the things that + + align:start position:0% +the following uh one of the things that + + + align:start position:0% +the following uh one of the things that +was done by not Arthur Compton but by + + align:start position:0% +was done by not Arthur Compton but by + + + align:start position:0% +was done by not Arthur Compton but by +Carl Compton soon after he became + + align:start position:0% +Carl Compton soon after he became + + + align:start position:0% +Carl Compton soon after he became +president in 1930 president of MIT + + align:start position:0% +president in 1930 president of MIT + + + align:start position:0% +president in 1930 president of MIT +and this is for all you physics majors + + align:start position:0% +and this is for all you physics majors + + + align:start position:0% +and this is for all you physics majors +and my apologies to every other + + align:start position:0% +and my apologies to every other + + + align:start position:0% +and my apologies to every other +engineering major you know who you are + + align:start position:0% +engineering major you know who you are + + + align:start position:0% +engineering major you know who you are +Compton decided that MIT become too + + align:start position:0% +Compton decided that MIT become too + + + align:start position:0% +Compton decided that MIT become too +closely aligned to both engineering and + + align:start position:0% +closely aligned to both engineering and + + + align:start position:0% +closely aligned to both engineering and +Industry he thought his Compton's own + + align:start position:0% +Industry he thought his Compton's own + + + align:start position:0% +Industry he thought his Compton's own +words the MIT had sold its soul to + + align:start position:0% +words the MIT had sold its soul to + + + align:start position:0% +words the MIT had sold its soul to +industrialists and so it was time for + + align:start position:0% +industrialists and so it was time for + + + align:start position:0% +industrialists and so it was time for +MIT to redouble on the basic Sciences + + align:start position:0% +MIT to redouble on the basic Sciences + + + align:start position:0% +MIT to redouble on the basic Sciences +it was at this time starting in 1930 + + align:start position:0% +it was at this time starting in 1930 + + + align:start position:0% +it was at this time starting in 1930 +when Compton Carl Compton put into a + + align:start position:0% +when Compton Carl Compton put into a + + + align:start position:0% +when Compton Carl Compton put into a +reform that every single undergraduate + + align:start position:0% +reform that every single undergraduate + + + align:start position:0% +reform that every single undergraduate +MIT had to take two whole years of + + align:start position:0% +MIT had to take two whole years of + + + align:start position:0% +MIT had to take two whole years of +physics you little whips kidding just + + align:start position:0% +physics you little whips kidding just + + + align:start position:0% +physics you little whips kidding just +kidding you wonderful students only have + + align:start position:0% +kidding you wonderful students only have + + + align:start position:0% +kidding you wonderful students only have +to take one year of physics because MIT + + align:start position:0% +to take one year of physics because MIT + + + align:start position:0% +to take one year of physics because MIT +relented in 1965. for 35 years Carl + + align:start position:0% +relented in 1965. for 35 years Carl + + + align:start position:0% +relented in 1965. for 35 years Carl +Compton's Vision held and literally + + align:start position:0% +Compton's Vision held and literally + + + align:start position:0% +Compton's Vision held and literally +every every ma2 student whether they + + align:start position:0% +every every ma2 student whether they + + + align:start position:0% +every every ma2 student whether they +were management majors at the Sloan + + align:start position:0% +were management majors at the Sloan + + + align:start position:0% +were management majors at the Sloan +school I'm looking at Gary or you know + + align:start position:0% +school I'm looking at Gary or you know + + + align:start position:0% +school I'm looking at Gary or you know +economics major or history or or + + align:start position:0% +economics major or history or or + + + align:start position:0% +economics major or history or or +mathematics had to take two years of + + align:start position:0% +mathematics had to take two years of + + + align:start position:0% +mathematics had to take two years of +physics it wasn't quite the Cambridge + + align:start position:0% +physics it wasn't quite the Cambridge + + + align:start position:0% +physics it wasn't quite the Cambridge +Wranglers but we had to two years + + align:start position:0% +Wranglers but we had to two years + + + align:start position:0% +Wranglers but we had to two years +because Carl Compton the physicist was + + align:start position:0% +because Carl Compton the physicist was + + + align:start position:0% +because Carl Compton the physicist was +convinced that we had to have a whole + + align:start position:0% +convinced that we had to have a whole + + + align:start position:0% +convinced that we had to have a whole +new emphasis on on the so-called basic + + align:start position:0% +new emphasis on on the so-called basic + + + align:start position:0% +new emphasis on on the so-called basic +Sciences it's at this time when the + + align:start position:0% +Sciences it's at this time when the + + + align:start position:0% +Sciences it's at this time when the +laboratory requirements start coming in + + align:start position:0% +laboratory requirements start coming in + + + align:start position:0% +laboratory requirements start coming in +for uh biology and chemistry and + + align:start position:0% +for uh biology and chemistry and + + + align:start position:0% +for uh biology and chemistry and +Mathematics + + align:start position:0% +Mathematics + + + align:start position:0% +Mathematics +it was only uh 35 years later in the + + align:start position:0% +it was only uh 35 years later in the + + + align:start position:0% +it was only uh 35 years later in the +mid-1960s when some um some colleagues + + align:start position:0% +mid-1960s when some um some colleagues + + + align:start position:0% +mid-1960s when some um some colleagues +long after uh Carl Compton sat down and + + align:start position:0% +long after uh Carl Compton sat down and + + + align:start position:0% +long after uh Carl Compton sat down and +said maybe that's too much physics for + + align:start position:0% +said maybe that's too much physics for + + + align:start position:0% +said maybe that's too much physics for +every single student and honestly when I + + align:start position:0% +every single student and honestly when I + + + align:start position:0% +every single student and honestly when I +started teaching at MIT in 2000 some of + + align:start position:0% +started teaching at MIT in 2000 some of + + + align:start position:0% +started teaching at MIT in 2000 some of +my then rather senior colleagues still + + align:start position:0% +my then rather senior colleagues still + + + align:start position:0% +my then rather senior colleagues still +remembered 1965 and thought everything + + align:start position:0% +remembered 1965 and thought everything + + + align:start position:0% +remembered 1965 and thought everything +had gone downhill since then those + + align:start position:0% +had gone downhill since then those + + + align:start position:0% +had gone downhill since then those +people have since retired but like MIT + + align:start position:0% +people have since retired but like MIT + + + align:start position:0% +people have since retired but like MIT +has never been the same in their point + + align:start position:0% +has never been the same in their point + + + align:start position:0% +has never been the same in their point +of view since we gave up forcing slash + + align:start position:0% +of view since we gave up forcing slash + + + align:start position:0% +of view since we gave up forcing slash +inviting every single undergraduate to + + align:start position:0% +inviting every single undergraduate to + + + align:start position:0% +inviting every single undergraduate to +take two whole years of physics so + + align:start position:0% +take two whole years of physics so + + + align:start position:0% +take two whole years of physics so +that's one of the legacies of Carla + + align:start position:0% +that's one of the legacies of Carla + + + align:start position:0% +that's one of the legacies of Carla +Compton not Arthur Compton + + align:start position:0% +Compton not Arthur Compton + + + align:start position:0% +Compton not Arthur Compton +um + + align:start position:0% +um + + + align:start position:0% +um +it's true Alex puts in the chat where + + align:start position:0% +it's true Alex puts in the chat where + + + align:start position:0% +it's true Alex puts in the chat where +the problem sets originally questions + + align:start position:0% +the problem sets originally questions + + + align:start position:0% +the problem sets originally questions +from industry many of them were in fact + + align:start position:0% +from industry many of them were in fact + + + align:start position:0% +from industry many of them were in fact +if not problem sets then certainly + + align:start position:0% +if not problem sets then certainly + + + align:start position:0% +if not problem sets then certainly +research projects there was a kind of um + + align:start position:0% +research projects there was a kind of um + + + align:start position:0% +research projects there was a kind of um +research for hire program which which + + align:start position:0% +research for hire program which which + + + align:start position:0% +research for hire program which which +never really ended but was was a very + + align:start position:0% +never really ended but was was a very + + + align:start position:0% +never really ended but was was a very +high focus at MIT starting soon after + + align:start position:0% +high focus at MIT starting soon after + + + align:start position:0% +high focus at MIT starting soon after +the first world war after in the years + + align:start position:0% +the first world war after in the years + + + align:start position:0% +the first world war after in the years +right after 1918. it was called the MIT + + align:start position:0% +right after 1918. it was called the MIT + + + align:start position:0% +right after 1918. it was called the MIT +plan or the tech plan + + align:start position:0% +plan or the tech plan + + + align:start position:0% +plan or the tech plan +and roughly 12 to 15 years into that + + align:start position:0% +and roughly 12 to 15 years into that + + + align:start position:0% +and roughly 12 to 15 years into that +there was a kind of correct course + + align:start position:0% +there was a kind of correct course + + + align:start position:0% +there was a kind of correct course +correction and people like Carl + + align:start position:0% +correction and people like Carl + + + align:start position:0% +correction and people like Carl +conference that we have to rejigger that + + align:start position:0% +conference that we have to rejigger that + + + align:start position:0% +conference that we have to rejigger that +Fisher says I assume this requirement + + align:start position:0% +Fisher says I assume this requirement + + + align:start position:0% +Fisher says I assume this requirement +naturally only applied to physics and + + align:start position:0% +naturally only applied to physics and + + + align:start position:0% +naturally only applied to physics and +how about no that's right Fisher's + + align:start position:0% +how about no that's right Fisher's + + + align:start position:0% +how about no that's right Fisher's +exactly right so the requirement of two + + align:start position:0% +exactly right so the requirement of two + + + align:start position:0% +exactly right so the requirement of two +years a physics coursework applied only + + align:start position:0% +years a physics coursework applied only + + + align:start position:0% +years a physics coursework applied only +to physics for every single + + align:start position:0% +to physics for every single + + + align:start position:0% +to physics for every single +undergraduate and grudgingly if you had + + align:start position:0% +undergraduate and grudgingly if you had + + + align:start position:0% +undergraduate and grudgingly if you had +to take chemistry or biology fine that + + align:start position:0% +to take chemistry or biology fine that + + + align:start position:0% +to take chemistry or biology fine that +was required you have to take + + align:start position:0% +was required you have to take + + + align:start position:0% +was required you have to take +Laboratories I had to take at least one + + align:start position:0% +Laboratories I had to take at least one + + + align:start position:0% +Laboratories I had to take at least one +year of mathematics so we can recognize + + align:start position:0% +year of mathematics so we can recognize + + + align:start position:0% +year of mathematics so we can recognize +parts of our so-called girs to this day + + align:start position:0% +parts of our so-called girs to this day + + + align:start position:0% +parts of our so-called girs to this day +survive from Carl Compton's era even + + align:start position:0% +survive from Carl Compton's era even + + + align:start position:0% +survive from Carl Compton's era even +though critically the one horrible moral + + align:start position:0% +though critically the one horrible moral + + + align:start position:0% +though critically the one horrible moral +lapse According to some of my colleagues + + align:start position:0% +lapse According to some of my colleagues + + + align:start position:0% +lapse According to some of my colleagues +was dropping the two years of physics in + + align:start position:0% +was dropping the two years of physics in + + + align:start position:0% +was dropping the two years of physics in +place of only one I leave you with that + + align:start position:0% +place of only one I leave you with that + + + align:start position:0% +place of only one I leave you with that +thought uh I invite you all to take more + + align:start position:0% +thought uh I invite you all to take more + + + align:start position:0% +thought uh I invite you all to take more +than one year of physics I think many of + + align:start position:0% +than one year of physics I think many of + + + align:start position:0% +than one year of physics I think many of +you have been anyway because of physics + + align:start position:0% +you have been anyway because of physics + + + align:start position:0% +you have been anyway because of physics +Majors that's Carl Compton I'd like to + + align:start position:0% +Majors that's Carl Compton I'd like to + + + align:start position:0% +Majors that's Carl Compton I'd like to +talk more about Carl Compton and MIT in + + align:start position:0% +talk more about Carl Compton and MIT in + + + align:start position:0% +talk more about Carl Compton and MIT in +the coming weeks when we talk about MIT + + align:start position:0% +the coming weeks when we talk about MIT + + + align:start position:0% +the coming weeks when we talk about MIT +in the second world war and radar we'll + + align:start position:0% +in the second world war and radar we'll + + + align:start position:0% +in the second world war and radar we'll +hear Carl Compton's name again soon in + + align:start position:0% +hear Carl Compton's name again soon in + + + align:start position:0% +hear Carl Compton's name again soon in +the meantime we'll pause and sit with + + align:start position:0% +the meantime we'll pause and sit with + + + align:start position:0% +the meantime we'll pause and sit with +Arthur Compton's results for which again + + align:start position:0% +Arthur Compton's results for which again + + + align:start position:0% +Arthur Compton's results for which again +there's more of the algebra in those + + align:start position:0% +there's more of the algebra in those + + + align:start position:0% +there's more of the algebra in those +notes if if that went by too quickly any + + align:start position:0% +notes if if that went by too quickly any + + + align:start position:0% +notes if if that went by too quickly any +other questions uh about this material + + align:start position:0% +other questions uh about this material + + + align:start position:0% +other questions uh about this material +anyone wish that everyone had to take + + align:start position:0% +anyone wish that everyone had to take + + + align:start position:0% +anyone wish that everyone had to take +two years of physics or any other + + align:start position:0% +two years of physics or any other + + + align:start position:0% +two years of physics or any other +comments on on today's class + + align:start position:0% +comments on on today's class + + + align:start position:0% +comments on on today's class +if not I'll leave it there I'll wish you + + align:start position:0% +if not I'll leave it there I'll wish you + + + align:start position:0% +if not I'll leave it there I'll wish you +good luck wrapping up your paper one + + align:start position:0% +good luck wrapping up your paper one + + + align:start position:0% +good luck wrapping up your paper one +draft please don't forget let's do this + + align:start position:0% +draft please don't forget let's do this + + + align:start position:0% +draft please don't forget let's do this +Friday and we'll pick up the story of + + align:start position:0% +Friday and we'll pick up the story of + + + align:start position:0% +Friday and we'll pick up the story of +old quantum theory again with our next + + align:start position:0% +old quantum theory again with our next + + + align:start position:0% +old quantum theory again with our next +class + + align:start position:0% +class + + + align:start position:0% +class +thanks so much gang stay well \ No newline at end of file diff --git a/HxfSOdFOqkk.txt b/HxfSOdFOqkk.txt new file mode 100644 index 0000000000000000000000000000000000000000..6c0753bbf02a53981e10c4fef2e3846ab7392d3a --- /dev/null +++ b/HxfSOdFOqkk.txt @@ -0,0 +1,3080 @@ +align:start position:0% + +all right you're probably wondering why + + align:start position:0% +all right you're probably wondering why + + + align:start position:0% +all right you're probably wondering why +there's so many pipes out here + + align:start position:0% +there's so many pipes out here + + + align:start position:0% +there's so many pipes out here +um back in um + + align:start position:0% +um back in um + + + align:start position:0% +um back in um +back in 1985 80 actually earlier in 93 + + align:start position:0% +back in 1985 80 actually earlier in 93 + + + align:start position:0% +back in 1985 80 actually earlier in 93 + + align:start position:0% + + + align:start position:0% +we uh we had we had just we had + + align:start position:0% +we uh we had we had just we had + + + align:start position:0% +we uh we had we had just we had +discovered the sewage plume we were + + align:start position:0% +discovered the sewage plume we were + + + align:start position:0% +discovered the sewage plume we were +beginning to get a feeling for what it + + align:start position:0% +beginning to get a feeling for what it + + + align:start position:0% +beginning to get a feeling for what it +looked like and everything else + + align:start position:0% +looked like and everything else + + + align:start position:0% +looked like and everything else +and um one of the big questions at the + + align:start position:0% +and um one of the big questions at the + + + align:start position:0% +and um one of the big questions at the +time in in the hydro groundwater + + align:start position:0% +time in in the hydro groundwater + + + align:start position:0% +time in in the hydro groundwater +hydrology was the rate at which + + align:start position:0% +hydrology was the rate at which + + + align:start position:0% +hydrology was the rate at which +contaminants disperse + + align:start position:0% +contaminants disperse + + + align:start position:0% +contaminants disperse +you know how how quickly will if you put + + align:start position:0% +you know how how quickly will if you put + + + align:start position:0% +you know how how quickly will if you put +in a if you had a spill + + align:start position:0% +in a if you had a spill + + + align:start position:0% +in a if you had a spill +from a septic tank or a you know fuel + + align:start position:0% +from a septic tank or a you know fuel + + + align:start position:0% +from a septic tank or a you know fuel +spill or whatever else + + align:start position:0% +spill or whatever else + + + align:start position:0% +spill or whatever else +and and it got in the aquifer and it + + align:start position:0% +and and it got in the aquifer and it + + + align:start position:0% +and and it got in the aquifer and it +begins to migrate with the natural + + align:start position:0% +begins to migrate with the natural + + + align:start position:0% +begins to migrate with the natural +groundwater flow how quickly would it + + align:start position:0% +groundwater flow how quickly would it + + + align:start position:0% +groundwater flow how quickly would it +get diluted and dispersed to the point + + align:start position:0% +get diluted and dispersed to the point + + + align:start position:0% +get diluted and dispersed to the point +where + + align:start position:0% +where + + + align:start position:0% +where +it wouldn't be a problem and there were + + align:start position:0% +it wouldn't be a problem and there were + + + align:start position:0% +it wouldn't be a problem and there were +a lot of + + align:start position:0% +a lot of + + + align:start position:0% +a lot of +ideas about how quickly that happened + + align:start position:0% +ideas about how quickly that happened + + + align:start position:0% +ideas about how quickly that happened +and what caused it + + align:start position:0% +and what caused it + + + align:start position:0% +and what caused it +and what they what a number of folks + + align:start position:0% +and what they what a number of folks + + + align:start position:0% +and what they what a number of folks +were able to demonstrate is that + + align:start position:0% +were able to demonstrate is that + + + align:start position:0% +were able to demonstrate is that +the primary cause of the dispersion in + + align:start position:0% +the primary cause of the dispersion in + + + align:start position:0% +the primary cause of the dispersion in +groundwater + + align:start position:0% +groundwater + + + align:start position:0% +groundwater +unlike in surface waters or in the + + align:start position:0% +unlike in surface waters or in the + + + align:start position:0% +unlike in surface waters or in the +atmosphere which is turbulence there's + + align:start position:0% +atmosphere which is turbulence there's + + + align:start position:0% +atmosphere which is turbulence there's +no turbulence in groundwater it moves + + align:start position:0% +no turbulence in groundwater it moves + + + align:start position:0% +no turbulence in groundwater it moves +through slowly + + align:start position:0% +through slowly + + + align:start position:0% +through slowly +you probably have you know heard about + + align:start position:0% +you probably have you know heard about + + + align:start position:0% +you probably have you know heard about +laminar flow it's really kind of almost + + align:start position:0% +laminar flow it's really kind of almost + + + align:start position:0% +laminar flow it's really kind of almost +limiter + + align:start position:0% +limiter + + + align:start position:0% +limiter +is is the actual heterogeneity of the + + align:start position:0% +is is the actual heterogeneity of the + + + align:start position:0% +is is the actual heterogeneity of the +subsurface + + align:start position:0% +subsurface + + + align:start position:0% +subsurface +in other words even the most uniform + + align:start position:0% +in other words even the most uniform + + + align:start position:0% +in other words even the most uniform +quote unquote aquifer like a sand and + + align:start position:0% +quote unquote aquifer like a sand and + + + align:start position:0% +quote unquote aquifer like a sand and +gravel outwash like this is + + align:start position:0% +gravel outwash like this is + + + align:start position:0% +gravel outwash like this is +actually has a fair amount of lensing + + align:start position:0% +actually has a fair amount of lensing + + + align:start position:0% +actually has a fair amount of lensing +and layering because it's a natural + + align:start position:0% +and layering because it's a natural + + + align:start position:0% +and layering because it's a natural +geologic deposit + + align:start position:0% +geologic deposit + + + align:start position:0% +geologic deposit +you know it has beds you know + + align:start position:0% +you know it has beds you know + + + align:start position:0% +you know it has beds you know +sedimentation beds from + + align:start position:0% +sedimentation beds from + + + align:start position:0% +sedimentation beds from +running water so some some pioneers like + + align:start position:0% +running water so some some pioneers like + + + align:start position:0% +running water so some some pioneers like +lynn gelhar i don't know if lynn + + align:start position:0% +lynn gelhar i don't know if lynn + + + align:start position:0% +lynn gelhar i don't know if lynn +gelhardt comes into the lab at all or + + align:start position:0% +gelhardt comes into the lab at all or + + + align:start position:0% +gelhardt comes into the lab at all or +not + + align:start position:0% +not + + + align:start position:0% +not +anybody know lynn gelhart professor at + + align:start position:0% +anybody know lynn gelhart professor at + + + align:start position:0% +anybody know lynn gelhart professor at +mit he's retired now + + align:start position:0% +mit he's retired now + + + align:start position:0% +mit he's retired now +was one of the people who actually was + + align:start position:0% +was one of the people who actually was + + + align:start position:0% +was one of the people who actually was +able to demonstrate how you could + + align:start position:0% +able to demonstrate how you could + + + align:start position:0% +able to demonstrate how you could +predict the rate of dispersion if you + + align:start position:0% +predict the rate of dispersion if you + + + align:start position:0% +predict the rate of dispersion if you +could characterize the heterogeneity of + + align:start position:0% +could characterize the heterogeneity of + + + align:start position:0% +could characterize the heterogeneity of +the aquifer + + align:start position:0% +the aquifer + + + align:start position:0% +the aquifer +so if you could find some way of + + align:start position:0% +so if you could find some way of + + + align:start position:0% +so if you could find some way of +statistically characterizing how the + + align:start position:0% +statistically characterizing how the + + + align:start position:0% +statistically characterizing how the +hydraulic conductivity varied from place + + align:start position:0% +hydraulic conductivity varied from place + + + align:start position:0% +hydraulic conductivity varied from place +to place and how long + + align:start position:0% +to place and how long + + + align:start position:0% +to place and how long +the lenses and layers were and how thick + + align:start position:0% +the lenses and layers were and how thick + + + align:start position:0% +the lenses and layers were and how thick +they were + + align:start position:0% +they were + + + align:start position:0% +they were +that you could actually predict how + + align:start position:0% +that you could actually predict how + + + align:start position:0% +that you could actually predict how +rapidly contaminants would disperse + + align:start position:0% +rapidly contaminants would disperse + + + align:start position:0% +rapidly contaminants would disperse +so he and a few others had come up with + + align:start position:0% +so he and a few others had come up with + + + align:start position:0% +so he and a few others had come up with +various stochastic + + align:start position:0% +various stochastic + + + align:start position:0% +various stochastic +uh models of that process and the idea + + align:start position:0% +uh models of that process and the idea + + + align:start position:0% +uh models of that process and the idea +was that you know is there any reality + + align:start position:0% +was that you know is there any reality + + + align:start position:0% +was that you know is there any reality +to them at all + + align:start position:0% +to them at all + + + align:start position:0% +to them at all +so um we teamed up with uh professor + + align:start position:0% +so um we teamed up with uh professor + + + align:start position:0% +so um we teamed up with uh professor +gelhart at mit + + align:start position:0% +gelhart at mit + + + align:start position:0% +gelhart at mit +one of his phd students lynn uh steve + + align:start position:0% +one of his phd students lynn uh steve + + + align:start position:0% +one of his phd students lynn uh steve +garrobinian and i + + align:start position:0% +garrobinian and i + + + align:start position:0% +garrobinian and i +and a few others uh that we hired to + + align:start position:0% +and a few others uh that we hired to + + + align:start position:0% +and a few others uh that we hired to +help us out and we ran a tracer + + align:start position:0% +help us out and we ran a tracer + + + align:start position:0% +help us out and we ran a tracer +experiment + + align:start position:0% +experiment + + + align:start position:0% +experiment +to try to measure the rate of dispersion + + align:start position:0% +to try to measure the rate of dispersion + + + align:start position:0% +to try to measure the rate of dispersion +in the aquifer so our idea was we would + + align:start position:0% +in the aquifer so our idea was we would + + + align:start position:0% +in the aquifer so our idea was we would +create our own little + + align:start position:0% +create our own little + + + align:start position:0% +create our own little +plume and we would monitor it as it + + align:start position:0% +plume and we would monitor it as it + + + align:start position:0% +plume and we would monitor it as it +moved through the aquifer and actually + + align:start position:0% +moved through the aquifer and actually + + + align:start position:0% +moved through the aquifer and actually +by collecting water samples in three + + align:start position:0% +by collecting water samples in three + + + align:start position:0% +by collecting water samples in three +dimensions so we'd have a detailed 3d + + align:start position:0% +dimensions so we'd have a detailed 3d + + + align:start position:0% +dimensions so we'd have a detailed 3d +snapshot of this tracer plume + + align:start position:0% +snapshot of this tracer plume + + + align:start position:0% +snapshot of this tracer plume +we could actually measure how rapidly it + + align:start position:0% +we could actually measure how rapidly it + + + align:start position:0% +we could actually measure how rapidly it +dispersed and spread + + align:start position:0% +dispersed and spread + + + align:start position:0% +dispersed and spread +and then we could compare that to other + + align:start position:0% +and then we could compare that to other + + + align:start position:0% +and then we could compare that to other +measurements of the aquifer's + + align:start position:0% +measurements of the aquifer's + + + align:start position:0% +measurements of the aquifer's +heterogeneity and see if the theories + + align:start position:0% +heterogeneity and see if the theories + + + align:start position:0% +heterogeneity and see if the theories +were right + + align:start position:0% +were right + + + align:start position:0% +were right +so it was it was a a massive tracer + + align:start position:0% +so it was it was a a massive tracer + + + align:start position:0% +so it was it was a a massive tracer +experiment so what we did is uh + + align:start position:0% +experiment so what we did is uh + + + align:start position:0% +experiment so what we did is uh +we picked this spot somebody had asked + + align:start position:0% +we picked this spot somebody had asked + + + align:start position:0% +we picked this spot somebody had asked +me why did you pick this spot + + align:start position:0% +me why did you pick this spot + + + align:start position:0% +me why did you pick this spot +uh well we picked this spot to run the + + align:start position:0% +uh well we picked this spot to run the + + + align:start position:0% +uh well we picked this spot to run the +tracer experiment for a couple of + + align:start position:0% +tracer experiment for a couple of + + + align:start position:0% +tracer experiment for a couple of +reasons first of all it was an abandoned + + align:start position:0% +reasons first of all it was an abandoned + + + align:start position:0% +reasons first of all it was an abandoned +gravel pit + + align:start position:0% +gravel pit + + + align:start position:0% +gravel pit +and uh so it was flat and easy to work + + align:start position:0% +and uh so it was flat and easy to work + + + align:start position:0% +and uh so it was flat and easy to work +in secondly it was on state-owned land + + align:start position:0% +in secondly it was on state-owned land + + + align:start position:0% +in secondly it was on state-owned land +so we had permission to do it + + align:start position:0% +so we had permission to do it + + + align:start position:0% +so we had permission to do it +and thirdly uh the groundwater was + + align:start position:0% +and thirdly uh the groundwater was + + + align:start position:0% +and thirdly uh the groundwater was +already contaminated here + + align:start position:0% +already contaminated here + + + align:start position:0% +already contaminated here +because of the sewage disposal so we + + align:start position:0% +because of the sewage disposal so we + + + align:start position:0% +because of the sewage disposal so we +were able to get permission from the + + align:start position:0% +were able to get permission from the + + + align:start position:0% +were able to get permission from the +state to create our own plume within a + + align:start position:0% +state to create our own plume within a + + + align:start position:0% +state to create our own plume within a +plume + + align:start position:0% +plume + + + align:start position:0% +plume +you know if we had gone through a + + align:start position:0% +you know if we had gone through a + + + align:start position:0% +you know if we had gone through a +pristine aquifer they would have gone + + align:start position:0% +pristine aquifer they would have gone + + + align:start position:0% +pristine aquifer they would have gone +are you nuts you want to add a + + align:start position:0% +are you nuts you want to add a + + + align:start position:0% +are you nuts you want to add a +contaminant + + align:start position:0% +contaminant + + + align:start position:0% +contaminant +you know so uh so we were able to do it + + align:start position:0% +you know so uh so we were able to do it + + + align:start position:0% +you know so uh so we were able to do it +right here so what we did on uh + + align:start position:0% +right here so what we did on uh + + + align:start position:0% +right here so what we did on uh +in july 1985 we uh see the three wells + + align:start position:0% +in july 1985 we uh see the three wells + + + align:start position:0% +in july 1985 we uh see the three wells +with the + + align:start position:0% +with the + + + align:start position:0% +with the +yellow labels up there the three wells + + align:start position:0% +yellow labels up there the three wells + + + align:start position:0% +yellow labels up there the three wells +those are all screened uh just below the + + align:start position:0% +those are all screened uh just below the + + + align:start position:0% +those are all screened uh just below the +water table they're shallow wells + + align:start position:0% +water table they're shallow wells + + + align:start position:0% +water table they're shallow wells +we uh we pumped two thousand gallons of + + align:start position:0% +we uh we pumped two thousand gallons of + + + align:start position:0% +we uh we pumped two thousand gallons of +water out of the aquifer into tanks + + align:start position:0% +water out of the aquifer into tanks + + + align:start position:0% +water out of the aquifer into tanks +this was clean groundwater pristine + + align:start position:0% +this was clean groundwater pristine + + + align:start position:0% +this was clean groundwater pristine +groundwater we added a number of traces + + align:start position:0% +groundwater we added a number of traces + + + align:start position:0% +groundwater we added a number of traces +to the water and in particular the one + + align:start position:0% +to the water and in particular the one + + + align:start position:0% +to the water and in particular the one +i'll talk about today is bromide + + align:start position:0% +i'll talk about today is bromide + + + align:start position:0% +i'll talk about today is bromide +uh like chloride it's very non-reactive + + align:start position:0% +uh like chloride it's very non-reactive + + + align:start position:0% +uh like chloride it's very non-reactive +so it's a good tracer of the water + + align:start position:0% +so it's a good tracer of the water + + + align:start position:0% +so it's a good tracer of the water +and bromide levels in the aquifer + + align:start position:0% +and bromide levels in the aquifer + + + align:start position:0% +and bromide levels in the aquifer +naturally are very low so we had a good + + align:start position:0% +naturally are very low so we had a good + + + align:start position:0% +naturally are very low so we had a good +signature of the water we put in as + + align:start position:0% +signature of the water we put in as + + + align:start position:0% +signature of the water we put in as +opposed to the background water + + align:start position:0% +opposed to the background water + + + align:start position:0% +opposed to the background water +right and then we uh we injected it over + + align:start position:0% +right and then we uh we injected it over + + + align:start position:0% +right and then we uh we injected it over +a very short period of time + + align:start position:0% +a very short period of time + + + align:start position:0% +a very short period of time +about a day took about about 19 hours + + align:start position:0% +about a day took about about 19 hours + + + align:start position:0% +about a day took about about 19 hours +into those three wells + + align:start position:0% +into those three wells + + + align:start position:0% +into those three wells +so what we did is we created a pulse + + align:start position:0% +so what we did is we created a pulse + + + align:start position:0% +so what we did is we created a pulse +you know on the time scale of years + + align:start position:0% +you know on the time scale of years + + + align:start position:0% +you know on the time scale of years +essentially instantaneous pulse in the + + align:start position:0% +essentially instantaneous pulse in the + + + align:start position:0% +essentially instantaneous pulse in the +aquifer + + align:start position:0% +aquifer + + + align:start position:0% +aquifer +a bromide cloud and if you just did some + + align:start position:0% +a bromide cloud and if you just did some + + + align:start position:0% +a bromide cloud and if you just did some +simple calculations it would have been + + align:start position:0% +simple calculations it would have been + + + align:start position:0% +simple calculations it would have been +about four meters by four meters by + + align:start position:0% +about four meters by four meters by + + + align:start position:0% +about four meters by four meters by +three meters + + align:start position:0% +three meters + + + align:start position:0% +three meters +now it didn't go in that thing more like + + align:start position:0% +now it didn't go in that thing more like + + + align:start position:0% +now it didn't go in that thing more like +a beautiful box but that was roughly the + + align:start position:0% +a beautiful box but that was roughly the + + + align:start position:0% +a beautiful box but that was roughly the +size we expected it to be + + align:start position:0% +size we expected it to be + + + align:start position:0% +size we expected it to be +all right and then what we did is we + + align:start position:0% +all right and then what we did is we + + + align:start position:0% +all right and then what we did is we +then let the natural flow carry it + + align:start position:0% +then let the natural flow carry it + + + align:start position:0% +then let the natural flow carry it +downstream how did we know which way it + + align:start position:0% +downstream how did we know which way it + + + align:start position:0% +downstream how did we know which way it +would go we'd done all those water table + + align:start position:0% +would go we'd done all those water table + + + align:start position:0% +would go we'd done all those water table +wells first we had mapped the water + + align:start position:0% +wells first we had mapped the water + + + align:start position:0% +wells first we had mapped the water +table out here in detail + + align:start position:0% +table out here in detail + + + align:start position:0% +table out here in detail +and we could predict which direction it + + align:start position:0% +and we could predict which direction it + + + align:start position:0% +and we could predict which direction it +would take more or less + + align:start position:0% +would take more or less + + + align:start position:0% +would take more or less +all right and uh so then we started to + + align:start position:0% +all right and uh so then we started to + + + align:start position:0% +all right and uh so then we started to +track it + + align:start position:0% +track it + + + align:start position:0% +track it +and the way we did that was by using + + align:start position:0% +and the way we did that was by using + + + align:start position:0% +and the way we did that was by using +these multi-level samplers that we had + + align:start position:0% +these multi-level samplers that we had + + + align:start position:0% +these multi-level samplers that we had +drilled out ahead of it + + align:start position:0% +drilled out ahead of it + + + align:start position:0% +drilled out ahead of it +right so you can just imagine this + + align:start position:0% +right so you can just imagine this + + + align:start position:0% +right so you can just imagine this +process we um + + align:start position:0% +process we um + + + align:start position:0% +process we um +we inject the tracer and we had put in + + align:start position:0% +we inject the tracer and we had put in + + + align:start position:0% +we inject the tracer and we had put in +about 10 rows of samplers and we would + + align:start position:0% +about 10 rows of samplers and we would + + + align:start position:0% +about 10 rows of samplers and we would +come out here and look at them wow look + + align:start position:0% +come out here and look at them wow look + + + align:start position:0% +come out here and look at them wow look +at all those wells isn't that cool + + align:start position:0% +at all those wells isn't that cool + + + align:start position:0% +at all those wells isn't that cool +there were about 80 of them at the time + + align:start position:0% +there were about 80 of them at the time + + + align:start position:0% +there were about 80 of them at the time +and + + align:start position:0% +and + + + align:start position:0% +and +we injected the tracers and then right + + align:start position:0% +we injected the tracers and then right + + + align:start position:0% +we injected the tracers and then right +away i think the first time we did a + + align:start position:0% +away i think the first time we did a + + + align:start position:0% +away i think the first time we did a +sampling was 13 days later we went out + + align:start position:0% +sampling was 13 days later we went out + + + align:start position:0% +sampling was 13 days later we went out +and sampled as many of these multi-level + + align:start position:0% +and sampled as many of these multi-level + + + align:start position:0% +and sampled as many of these multi-level +samples as we could + + align:start position:0% +samples as we could + + + align:start position:0% +samples as we could +ran back to the lab and then analyzed + + align:start position:0% +ran back to the lab and then analyzed + + + align:start position:0% +ran back to the lab and then analyzed +the samples for bromide + + align:start position:0% +the samples for bromide + + + align:start position:0% +the samples for bromide +and tried to figure out where this + + align:start position:0% +and tried to figure out where this + + + align:start position:0% +and tried to figure out where this +tracer cloud was how big was it + + align:start position:0% +tracer cloud was how big was it + + + align:start position:0% +tracer cloud was how big was it +and on that basis we then would build + + align:start position:0% +and on that basis we then would build + + + align:start position:0% +and on that basis we then would build +more samplers + + align:start position:0% +more samplers + + + align:start position:0% +more samplers +get out ahead of where the cloud was + + align:start position:0% +get out ahead of where the cloud was + + + align:start position:0% +get out ahead of where the cloud was +going to go next based on our + + align:start position:0% +going to go next based on our + + + align:start position:0% +going to go next based on our +predictions + + align:start position:0% +predictions + + + align:start position:0% +predictions +drilled more samplers and then we + + align:start position:0% +drilled more samplers and then we + + + align:start position:0% +drilled more samplers and then we +leapfrogged for two years that way + + align:start position:0% +leapfrogged for two years that way + + + align:start position:0% +leapfrogged for two years that way +all the way down across the gravel pit + + align:start position:0% +all the way down across the gravel pit + + + align:start position:0% +all the way down across the gravel pit +so all these samplers were put in as + + align:start position:0% +so all these samplers were put in as + + + align:start position:0% +so all these samplers were put in as +part of that treasure test + + align:start position:0% +part of that treasure test + + + align:start position:0% +part of that treasure test +back in 1985. um + + align:start position:0% +back in 1985. um + + + align:start position:0% +back in 1985. um +these are all multi-level samplers so + + align:start position:0% +these are all multi-level samplers so + + + align:start position:0% +these are all multi-level samplers so +you're looking at a well field here this + + align:start position:0% +you're looking at a well field here this + + + align:start position:0% +you're looking at a well field here this +we've now since run about 70 tracer + + align:start position:0% +we've now since run about 70 tracer + + + align:start position:0% +we've now since run about 70 tracer +experiments out here so we've added some + + align:start position:0% +experiments out here so we've added some + + + align:start position:0% +experiments out here so we've added some +as we go along + + align:start position:0% +as we go along + + + align:start position:0% +as we go along +there's about a thousand out here which + + align:start position:0% +there's about a thousand out here which + + + align:start position:0% +there's about a thousand out here which +means there's 15 000 sampling points + + align:start position:0% +means there's 15 000 sampling points + + + align:start position:0% +means there's 15 000 sampling points +in the gravel pad + + align:start position:0% + + + + align:start position:0% + +that's a good question i i would guess + + align:start position:0% +that's a good question i i would guess + + + align:start position:0% +that's a good question i i would guess +uh it's hard it's hard to really put a + + align:start position:0% +uh it's hard it's hard to really put a + + + align:start position:0% +uh it's hard it's hard to really put a +number on it + + align:start position:0% +number on it + + + align:start position:0% +number on it +but let's just say a million dollars i + + align:start position:0% +but let's just say a million dollars i + + + align:start position:0% +but let's just say a million dollars i +mean i just + + align:start position:0% +mean i just + + + align:start position:0% +mean i just +i have no way of really telling you + + align:start position:0% +i have no way of really telling you + + + align:start position:0% +i have no way of really telling you +because it's old dollars versus new + + align:start position:0% +because it's old dollars versus new + + + align:start position:0% +because it's old dollars versus new +dollars and you know + + align:start position:0% +dollars and you know + + + align:start position:0% +dollars and you know +it's really hard to say and then we had + + align:start position:0% +it's really hard to say and then we had + + + align:start position:0% +it's really hard to say and then we had +a lot of researchers work with us that i + + align:start position:0% +a lot of researchers work with us that i + + + align:start position:0% +a lot of researchers work with us that i +didn't control their money + + align:start position:0% +didn't control their money + + + align:start position:0% +didn't control their money +you know i didn't fund them so uh my + + align:start position:0% +you know i didn't fund them so uh my + + + align:start position:0% +you know i didn't fund them so uh my +budgets were always less than a half a + + align:start position:0% +budgets were always less than a half a + + + align:start position:0% +budgets were always less than a half a +million + + align:start position:0% +million + + + align:start position:0% +million +they were they were uh typically a + + align:start position:0% +they were they were uh typically a + + + align:start position:0% +they were they were uh typically a +couple hundred thousand but then that + + align:start position:0% +couple hundred thousand but then that + + + align:start position:0% +couple hundred thousand but then that +was 1984 dollars you know so i don't + + align:start position:0% +was 1984 dollars you know so i don't + + + align:start position:0% +was 1984 dollars you know so i don't +know what it would be today + + align:start position:0% +know what it would be today + + + align:start position:0% +know what it would be today +so did you prove the stochastic model i + + align:start position:0% +so did you prove the stochastic model i + + + align:start position:0% +so did you prove the stochastic model i +came out uh frequently closed + + align:start position:0% +came out uh frequently closed + + + align:start position:0% +came out uh frequently closed +the one thing that surprised us was that + + align:start position:0% +the one thing that surprised us was that + + + align:start position:0% +the one thing that surprised us was that +the heterogeneity was much even though + + align:start position:0% +the heterogeneity was much even though + + + align:start position:0% +the heterogeneity was much even though +it looks heterogeneous + + align:start position:0% +it looks heterogeneous + + + align:start position:0% +it looks heterogeneous +i was going to take a pit for you today + + align:start position:0% +i was going to take a pit for you today + + + align:start position:0% +i was going to take a pit for you today +and i said no i'm not taking a fit for + + align:start position:0% +and i said no i'm not taking a fit for + + + align:start position:0% +and i said no i'm not taking a fit for +them today + + align:start position:0% +them today + + + align:start position:0% +them today +but uh it looks very very heterogeneous + + align:start position:0% +but uh it looks very very heterogeneous + + + align:start position:0% +but uh it looks very very heterogeneous +when you look at the lenses and layers + + align:start position:0% +when you look at the lenses and layers + + + align:start position:0% +when you look at the lenses and layers +but it's not that i'm a hydrological + + align:start position:0% +but it's not that i'm a hydrological + + + align:start position:0% +but it's not that i'm a hydrological +point of view it's pretty uniform + + align:start position:0% +point of view it's pretty uniform + + + align:start position:0% +point of view it's pretty uniform +and then we ran another test in 95 93 to + + align:start position:0% +and then we ran another test in 95 93 to + + + align:start position:0% +and then we ran another test in 95 93 to +95 another large-scale test where we did + + align:start position:0% +95 another large-scale test where we did + + + align:start position:0% +95 another large-scale test where we did +different reactive species + + align:start position:0% +different reactive species + + + align:start position:0% +different reactive species +but we again did bromide and got a very + + align:start position:0% +but we again did bromide and got a very + + + align:start position:0% +but we again did bromide and got a very +similar number + + align:start position:0% +similar number + + + align:start position:0% +similar number +uh so and it matched up again the + + align:start position:0% +uh so and it matched up again the + + + align:start position:0% +uh so and it matched up again the +stochastics pretty well + + align:start position:0% +stochastics pretty well + + + align:start position:0% +stochastics pretty well +so in fact the number of mit i think i + + align:start position:0% +so in fact the number of mit i think i + + + align:start position:0% +so in fact the number of mit i think i +want to tell you three mit phd thesis + + align:start position:0% +want to tell you three mit phd thesis + + + align:start position:0% +want to tell you three mit phd thesis +arose out of this test + + align:start position:0% +arose out of this test + + + align:start position:0% +arose out of this test +um so uh it was a fair number of + + align:start position:0% +um so uh it was a fair number of + + + align:start position:0% +um so uh it was a fair number of +mit folks were involved uh mainly lynn + + align:start position:0% +mit folks were involved uh mainly lynn + + + align:start position:0% +mit folks were involved uh mainly lynn +gelhardt students + + align:start position:0% +gelhardt students + + + align:start position:0% +gelhardt students +um and um so the way we sample them you + + align:start position:0% +um and um so the way we sample them you + + + align:start position:0% +um and um so the way we sample them you +can imagine trying to sample this + + align:start position:0% +can imagine trying to sample this + + + align:start position:0% +can imagine trying to sample this +the way we sample them you can imagine + + align:start position:0% +the way we sample them you can imagine + + + align:start position:0% +the way we sample them you can imagine +we come out here and we gotta take a + + align:start position:0% +we come out here and we gotta take a + + + align:start position:0% +we come out here and we gotta take a +snapshot of where the cloud is + + align:start position:0% +snapshot of where the cloud is + + + align:start position:0% +snapshot of where the cloud is +and we had a team of five of us we had + + align:start position:0% +and we had a team of five of us we had + + + align:start position:0% +and we had a team of five of us we had +two carts like this + + align:start position:0% +two carts like this + + + align:start position:0% +two carts like this +and instead of something one tube at a + + align:start position:0% +and instead of something one tube at a + + + align:start position:0% +and instead of something one tube at a +time we would hook up the milking + + align:start position:0% +time we would hook up the milking + + + align:start position:0% +time we would hook up the milking +machine + + align:start position:0% +machine + + + align:start position:0% +machine +like this and we had a chart that told + + align:start position:0% +like this and we had a chart that told + + + align:start position:0% +like this and we had a chart that told +us how much water we had to purge out to + + align:start position:0% +us how much water we had to purge out to + + + align:start position:0% +us how much water we had to purge out to +get rid of the old water + + align:start position:0% +get rid of the old water + + + align:start position:0% +get rid of the old water +and we would turn on the milking machine + + align:start position:0% + + + + align:start position:0% + +and they would all start to pump if + + align:start position:0% +and they would all start to pump if + + + align:start position:0% +and they would all start to pump if +we're lucky + + align:start position:0% + + + + align:start position:0% + +okay and um so the person would sit here + + align:start position:0% +okay and um so the person would sit here + + + align:start position:0% +okay and um so the person would sit here +they were + + align:start position:0% +they were + + + align:start position:0% +they were +they were the they would attach the + + align:start position:0% +they were the they would attach the + + + align:start position:0% +they were the they would attach the +milky machine and run the cart in order + + align:start position:0% +milky machine and run the cart in order + + + align:start position:0% +milky machine and run the cart in order +not to pump too much out of any one port + + align:start position:0% +not to pump too much out of any one port + + + align:start position:0% +not to pump too much out of any one port +because some yield really well you had a + + align:start position:0% +because some yield really well you had a + + + align:start position:0% +because some yield really well you had a +little cliff where you could stop the + + align:start position:0% +little cliff where you could stop the + + + align:start position:0% +little cliff where you could stop the +flow on one that was getting ahead of + + align:start position:0% +flow on one that was getting ahead of + + + align:start position:0% +flow on one that was getting ahead of +the others + + align:start position:0% +the others + + + align:start position:0% +the others +okay and we had these 60 milliliter + + align:start position:0% +okay and we had these 60 milliliter + + + align:start position:0% +okay and we had these 60 milliliter +bottles here what we would do is we + + align:start position:0% +bottles here what we would do is we + + + align:start position:0% +bottles here what we would do is we +would shove these in here + + align:start position:0% +would shove these in here + + + align:start position:0% +would shove these in here +and these were our rinse racks so let's + + align:start position:0% +and these were our rinse racks so let's + + + align:start position:0% +and these were our rinse racks so let's +say the chart said at this distance with + + align:start position:0% +say the chart said at this distance with + + + align:start position:0% +say the chart said at this distance with +this depth + + align:start position:0% +this depth + + + align:start position:0% +this depth +we need to pump out about 300 + + align:start position:0% +we need to pump out about 300 + + + align:start position:0% +we need to pump out about 300 +milliliters before you can take a sample + + align:start position:0% +milliliters before you can take a sample + + + align:start position:0% +milliliters before you can take a sample +we knew that was say five wrenches so we + + align:start position:0% +we knew that was say five wrenches so we + + + align:start position:0% +we knew that was say five wrenches so we +would shove this in + + align:start position:0% +would shove this in + + + align:start position:0% +would shove this in +we would fill them up when one side of + + align:start position:0% +we would fill them up when one side of + + + align:start position:0% +we would fill them up when one side of +the fill up would close it off when we + + align:start position:0% +the fill up would close it off when we + + + align:start position:0% +the fill up would close it off when we +had it all filled we would do this + + align:start position:0% +had it all filled we would do this + + + align:start position:0% +had it all filled we would do this +dump it off it would go into a bucket + + align:start position:0% +dump it off it would go into a bucket + + + align:start position:0% +dump it off it would go into a bucket +you shove it back in until you did your + + align:start position:0% +you shove it back in until you did your + + + align:start position:0% +you shove it back in until you did your +rinses + + align:start position:0% +rinses + + + align:start position:0% +rinses +then the person behind who was the + + align:start position:0% +then the person behind who was the + + + align:start position:0% +then the person behind who was the +bottle capper and the + + align:start position:0% +bottle capper and the + + + align:start position:0% +bottle capper and the +that's their job the cap bottles for + + align:start position:0% +that's their job the cap bottles for + + + align:start position:0% +that's their job the cap bottles for +four days straight um + + align:start position:0% +four days straight um + + + align:start position:0% +four days straight um +would have loaded a rack with the sample + + align:start position:0% +would have loaded a rack with the sample + + + align:start position:0% +would have loaded a rack with the sample +bottles in you'd shove that in fill your + + align:start position:0% +bottles in you'd shove that in fill your + + + align:start position:0% +bottles in you'd shove that in fill your +bottles up + + align:start position:0% +bottles up + + + align:start position:0% +bottles up +give it to them they'd cap them all like + + align:start position:0% +give it to them they'd cap them all like + + + align:start position:0% +give it to them they'd cap them all like +a madman while you went on to the next + + align:start position:0% +a madman while you went on to the next + + + align:start position:0% +a madman while you went on to the next +one + + align:start position:0% +one + + + align:start position:0% +one +and we would do that uh and we had uh so + + align:start position:0% +and we would do that uh and we had uh so + + + align:start position:0% +and we would do that uh and we had uh so +we had two carts and then we had the + + align:start position:0% +we had two carts and then we had the + + + align:start position:0% +we had two carts and then we had the +field general + + align:start position:0% +field general + + + align:start position:0% +field general +um anybody live at mccormick no that's + + align:start position:0% +um anybody live at mccormick no that's + + + align:start position:0% +um anybody live at mccormick no that's +an undergraduate dorm i guess right + + align:start position:0% +an undergraduate dorm i guess right + + + align:start position:0% +an undergraduate dorm i guess right +you know kathy hess yeah yeah + + align:start position:0% +you know kathy hess yeah yeah + + + align:start position:0% +you know kathy hess yeah yeah +kathy hess is the house mother at + + align:start position:0% +kathy hess is the house mother at + + + align:start position:0% +kathy hess is the house mother at +mccormick right or whenever you guys + + align:start position:0% +mccormick right or whenever you guys + + + align:start position:0% +mccormick right or whenever you guys +dorm + + align:start position:0% +dorm + + + align:start position:0% +dorm +house master she's my house she's my + + align:start position:0% +house master she's my house she's my + + + align:start position:0% +house master she's my house she's my +co-worker i call it val's mother + + align:start position:0% +co-worker i call it val's mother + + + align:start position:0% +co-worker i call it val's mother +uh there are some times when we sampled + + align:start position:0% +uh there are some times when we sampled + + + align:start position:0% +uh there are some times when we sampled +300 multi-level samplers + + align:start position:0% +300 multi-level samplers + + + align:start position:0% +300 multi-level samplers +three samples each port in three days + + align:start position:0% +three samples each port in three days + + + align:start position:0% +three samples each port in three days +so we could really fly take a snapshot + + align:start position:0% +so we could really fly take a snapshot + + + align:start position:0% +so we could really fly take a snapshot +we did that i think 18 times in the + + align:start position:0% +we did that i think 18 times in the + + + align:start position:0% +we did that i think 18 times in the +course of two years + + align:start position:0% + + + + align:start position:0% + +very quickly because we didn't have much + + align:start position:0% +very quickly because we didn't have much + + + align:start position:0% +very quickly because we didn't have much +time we had to get it going right away + + align:start position:0% +time we had to get it going right away + + + align:start position:0% +time we had to get it going right away +we also went to the university of + + align:start position:0% +we also went to the university of + + + align:start position:0% +we also went to the university of +waterloo who had done some similar + + align:start position:0% +waterloo who had done some similar + + + align:start position:0% +waterloo who had done some similar +experiments + + align:start position:0% +experiments + + + align:start position:0% +experiments +and um and you know really borrowed a + + align:start position:0% +and um and you know really borrowed a + + + align:start position:0% +and um and you know really borrowed a +lot of their ideas to be + + align:start position:0% +lot of their ideas to be + + + align:start position:0% +lot of their ideas to be +to be honest so uh you know we won't go + + align:start position:0% +to be honest so uh you know we won't go + + + align:start position:0% +to be honest so uh you know we won't go +into it in any more detail in that + + align:start position:0% +into it in any more detail in that + + + align:start position:0% +into it in any more detail in that +just to give you a sense for how it + + align:start position:0% +just to give you a sense for how it + + + align:start position:0% +just to give you a sense for how it +worked on page 10 + + align:start position:0% +worked on page 10 + + + align:start position:0% +worked on page 10 +it just shows you and 11 just shows you + + align:start position:0% +it just shows you and 11 just shows you + + + align:start position:0% +it just shows you and 11 just shows you +a couple of the results + + align:start position:0% + + + + align:start position:0% + +the uh and i won't go any further than + + align:start position:0% +the uh and i won't go any further than + + + align:start position:0% +the uh and i won't go any further than +that except to say that + + align:start position:0% +that except to say that + + + align:start position:0% +that except to say that +what we've discovered was when you + + align:start position:0% +what we've discovered was when you + + + align:start position:0% +what we've discovered was when you +injected the tracer as i mentioned + + align:start position:0% +injected the tracer as i mentioned + + + align:start position:0% +injected the tracer as i mentioned +before it was a pretty small volume + + align:start position:0% +before it was a pretty small volume + + + align:start position:0% +before it was a pretty small volume +within 30 days the tracer cloud was + + align:start position:0% +within 30 days the tracer cloud was + + + align:start position:0% +within 30 days the tracer cloud was +already + + align:start position:0% +already + + + align:start position:0% +already +pretty large in fact uh why don't we get + + align:start position:0% +pretty large in fact uh why don't we get + + + align:start position:0% +pretty large in fact uh why don't we get +uh we might as well do this it won't + + align:start position:0% +uh we might as well do this it won't + + + align:start position:0% +uh we might as well do this it won't +take + + align:start position:0% +take + + + align:start position:0% +take +a second see if i can figure this out + + align:start position:0% +a second see if i can figure this out + + + align:start position:0% +a second see if i can figure this out +here + + align:start position:0% + + + + align:start position:0% + +hey pete can i send you up as a runner + + align:start position:0% +hey pete can i send you up as a runner + + + align:start position:0% +hey pete can i send you up as a runner +and eric + + align:start position:0% + + + + align:start position:0% + +i want you to find i want you to go up + + align:start position:0% +i want you to find i want you to go up + + + align:start position:0% +i want you to find i want you to go up +to uh row one up there at the beginning + + align:start position:0% +to uh row one up there at the beginning + + + align:start position:0% +to uh row one up there at the beginning +and i want eric to find row 17. + + align:start position:0% +and i want eric to find row 17. + + + align:start position:0% +and i want eric to find row 17. +he'll say 17 on the covers + + align:start position:0% + + + + align:start position:0% + +faster and faster think of them as + + align:start position:0% +faster and faster think of them as + + + align:start position:0% +faster and faster think of them as +little bromides + + align:start position:0% + + + + align:start position:0% + +okay so there you go so by + + align:start position:0% +okay so there you go so by + + + align:start position:0% +okay so there you go so by +by 33 days the tracer cloud had moved + + align:start position:0% +by 33 days the tracer cloud had moved + + + align:start position:0% +by 33 days the tracer cloud had moved +from those injection points + + align:start position:0% +from those injection points + + + align:start position:0% +from those injection points +to where the one milligram per liter + + align:start position:0% +to where the one milligram per liter + + + align:start position:0% +to where the one milligram per liter +contour would have been this far south + + align:start position:0% +contour would have been this far south + + + align:start position:0% +contour would have been this far south +and that far north so it spread very + + align:start position:0% +and that far north so it spread very + + + align:start position:0% +and that far north so it spread very +very rapidly + + align:start position:0% +very rapidly + + + align:start position:0% +very rapidly +you know in a short period of time so by + + align:start position:0% +you know in a short period of time so by + + + align:start position:0% +you know in a short period of time so by +33 days this claw was already + + align:start position:0% +33 days this claw was already + + + align:start position:0% +33 days this claw was already +like 100 feet long but very very narrow + + align:start position:0% +like 100 feet long but very very narrow + + + align:start position:0% +like 100 feet long but very very narrow +it never got very narrow and then they + + align:start position:0% +it never got very narrow and then they + + + align:start position:0% +it never got very narrow and then they +migrated forward at a rate of one and a + + align:start position:0% +migrated forward at a rate of one and a + + + align:start position:0% +migrated forward at a rate of one and a +half feet per day + + align:start position:0% + + + + align:start position:0% + +so uh pete go to row 20 and eric + + align:start position:0% +so uh pete go to row 20 and eric + + + align:start position:0% +so uh pete go to row 20 and eric +you got to go to row 37. + + align:start position:0% +you got to go to row 37. + + + align:start position:0% +you got to go to row 37. +i think i have to leapfrog + + align:start position:0% + + + + align:start position:0% + +so by 139 days row 27 + + align:start position:0% +so by 139 days row 27 + + + align:start position:0% +so by 139 days row 27 +actually it's going to be beyond all of + + align:start position:0% +actually it's going to be beyond all of + + + align:start position:0% +actually it's going to be beyond all of +us here i think to row + + align:start position:0% +us here i think to row + + + align:start position:0% +us here i think to row +what did i tell you + + align:start position:0% + + + + align:start position:0% + +no you're 20. and he's 37. + + align:start position:0% + + + + align:start position:0% + +so you can see how how quickly it it uh + + align:start position:0% +so you can see how how quickly it it uh + + + align:start position:0% +so you can see how how quickly it it uh +spread in the longitudinal direction + + align:start position:0% +spread in the longitudinal direction + + + align:start position:0% +spread in the longitudinal direction +that's exactly what the stochastic + + align:start position:0% +that's exactly what the stochastic + + + align:start position:0% +that's exactly what the stochastic +theory said + + align:start position:0% +theory said + + + align:start position:0% +theory said +that most of the spreading should take + + align:start position:0% +that most of the spreading should take + + + align:start position:0% +that most of the spreading should take +place in the direction of flow and the + + align:start position:0% +place in the direction of flow and the + + + align:start position:0% +place in the direction of flow and the +plume actually never got very wide + + align:start position:0% +plume actually never got very wide + + + align:start position:0% +plume actually never got very wide +horizontally and in the vertical it + + align:start position:0% +horizontally and in the vertical it + + + align:start position:0% +horizontally and in the vertical it +stayed very very narrow + + align:start position:0% +stayed very very narrow + + + align:start position:0% +stayed very very narrow +uh it was only about uh six or seven + + align:start position:0% +uh it was only about uh six or seven + + + align:start position:0% +uh it was only about uh six or seven +meters thick + + align:start position:0% +meters thick + + + align:start position:0% +meters thick +there he is so that's how that's how + + align:start position:0% +there he is so that's how that's how + + + align:start position:0% +there he is so that's how that's how +long on the 139th day our sampling had + + align:start position:0% +long on the 139th day our sampling had + + + align:start position:0% +long on the 139th day our sampling had +to encompass + + align:start position:0% +to encompass + + + align:start position:0% +to encompass +all the samples from beyond pete to + + align:start position:0% +all the samples from beyond pete to + + + align:start position:0% +all the samples from beyond pete to +beyond eric + + align:start position:0% +beyond eric + + + align:start position:0% +beyond eric +and that was only 139 days okay + + align:start position:0% +and that was only 139 days okay + + + align:start position:0% +and that was only 139 days okay +thank you + + align:start position:0% + + + + align:start position:0% + +we always did it with five people we + + align:start position:0% +we always did it with five people we + + + align:start position:0% +we always did it with five people we +always did it with five people wow + + align:start position:0% + + + + align:start position:0% + +no we just we just worked an extra day + + align:start position:0% +no we just we just worked an extra day + + + align:start position:0% +no we just we just worked an extra day +yeah we just worked faster we got pretty + + align:start position:0% +yeah we just worked faster we got pretty + + + align:start position:0% +yeah we just worked faster we got pretty +good at it we were damn good at it + + align:start position:0% +good at it we were damn good at it + + + align:start position:0% +good at it we were damn good at it +we collected 100 000 water samples for + + align:start position:0% +we collected 100 000 water samples for + + + align:start position:0% +we collected 100 000 water samples for +the experiment \ No newline at end of file diff --git a/JtJ3v__Rx7E.txt b/JtJ3v__Rx7E.txt new file mode 100644 index 0000000000000000000000000000000000000000..30a0dd4cb5909e824e18051d362bbf0a7b8845cd --- /dev/null +++ b/JtJ3v__Rx7E.txt @@ -0,0 +1,7536 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit mitop courseware at + + align:start position:0% +of MIT courses visit mitop courseware at + + + align:start position:0% +of MIT courses visit mitop courseware at +ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +in the last several lectures we've + + align:start position:0% +in the last several lectures we've + + + align:start position:0% +in the last several lectures we've +considered a number of procedures for + + align:start position:0% +considered a number of procedures for + + + align:start position:0% +considered a number of procedures for +Designing digital filters for infinite + + align:start position:0% +Designing digital filters for infinite + + + align:start position:0% +Designing digital filters for infinite +impulse response for the class of + + align:start position:0% +impulse response for the class of + + + align:start position:0% +impulse response for the class of +infinite impulse response + + align:start position:0% +infinite impulse response + + + align:start position:0% +infinite impulse response +filters and the two primary design + + align:start position:0% +filters and the two primary design + + + align:start position:0% +filters and the two primary design +techniques that we considered in fact + + align:start position:0% +techniques that we considered in fact + + + align:start position:0% +techniques that we considered in fact +the two useful design techniques that we + + align:start position:0% +the two useful design techniques that we + + + align:start position:0% +the two useful design techniques that we +developed were the techniques which we + + align:start position:0% +developed were the techniques which we + + + align:start position:0% +developed were the techniques which we +referred to as impulse and variance and + + align:start position:0% +referred to as impulse and variance and + + + align:start position:0% +referred to as impulse and variance and +also the bilinear + + align:start position:0% +also the bilinear + + + align:start position:0% +also the bilinear +transformation you recall hopefully that + + align:start position:0% +transformation you recall hopefully that + + + align:start position:0% +transformation you recall hopefully that +both of these techniques are techniques + + align:start position:0% +both of these techniques are techniques + + + align:start position:0% +both of these techniques are techniques +that correspond to mapping a continuous + + align:start position:0% +that correspond to mapping a continuous + + + align:start position:0% +that correspond to mapping a continuous +time or analog filter to a digital + + align:start position:0% +time or analog filter to a digital + + + align:start position:0% +time or analog filter to a digital +filter what I'd like to do in this + + align:start position:0% +filter what I'd like to do in this + + + align:start position:0% +filter what I'd like to do in this +lecture is consider an example of the + + align:start position:0% +lecture is consider an example of the + + + align:start position:0% +lecture is consider an example of the +design of a digital low pass filter + + align:start position:0% +design of a digital low pass filter + + + align:start position:0% +design of a digital low pass filter +using each of these techniques using + + align:start position:0% +using each of these techniques using + + + align:start position:0% +using each of these techniques using +impulse and variance and the bilinear + + align:start position:0% +impulse and variance and the bilinear + + + align:start position:0% +impulse and variance and the bilinear +transformation and hopefully this will + + align:start position:0% +transformation and hopefully this will + + + align:start position:0% +transformation and hopefully this will +give you a better feeling for how both + + align:start position:0% +give you a better feeling for how both + + + align:start position:0% +give you a better feeling for how both +both of these techniques + + align:start position:0% +both of these techniques + + + align:start position:0% +both of these techniques +work the class of analog filters that I + + align:start position:0% +work the class of analog filters that I + + + align:start position:0% +work the class of analog filters that I +would like to use are the class of + + align:start position:0% +would like to use are the class of + + + align:start position:0% +would like to use are the class of +so-called analog Butterworth filters + + align:start position:0% +so-called analog Butterworth filters + + + align:start position:0% +so-called analog Butterworth filters +which are a useful class of low pass + + align:start position:0% +which are a useful class of low pass + + + align:start position:0% +which are a useful class of low pass +analog and digital filters and also a + + align:start position:0% +analog and digital filters and also a + + + align:start position:0% +analog and digital filters and also a +relatively simple + + align:start position:0% +relatively simple + + + align:start position:0% +relatively simple +class to first of all Define the class + + align:start position:0% +class to first of all Define the class + + + align:start position:0% +class to first of all Define the class +of analog filters that we're considering + + align:start position:0% +of analog filters that we're considering + + + align:start position:0% +of analog filters that we're considering +they are the class of analog Butterworth + + align:start position:0% +they are the class of analog Butterworth + + + align:start position:0% +they are the class of analog Butterworth +filters and this class of filters is + + align:start position:0% +filters and this class of filters is + + + align:start position:0% +filters and this class of filters is +defined by the analog system function H + + align:start position:0% +defined by the analog system function H + + + align:start position:0% +defined by the analog system function H +Suba of J Omega magnitude squared of the + + align:start position:0% +Suba of J Omega magnitude squared of the + + + align:start position:0% +Suba of J Omega magnitude squared of the +form 1 over 1 + J Omega / J Omega Sub C + + align:start position:0% +form 1 over 1 + J Omega / J Omega Sub C + + + align:start position:0% +form 1 over 1 + J Omega / J Omega Sub C +to the 2 N now there are two parameters + + align:start position:0% +to the 2 N now there are two parameters + + + align:start position:0% +to the 2 N now there are two parameters +in this expression one is the what's + + align:start position:0% +in this expression one is the what's + + + align:start position:0% +in this expression one is the what's +referred to often as the cutoff + + align:start position:0% +referred to often as the cutoff + + + align:start position:0% +referred to often as the cutoff +frequency Omega Sub C and the second is + + align:start position:0% +frequency Omega Sub C and the second is + + + align:start position:0% +frequency Omega Sub C and the second is +the order of the filter namely n let me + + align:start position:0% +the order of the filter namely n let me + + + align:start position:0% +the order of the filter namely n let me +remind you that we're looking at here an + + align:start position:0% +remind you that we're looking at here an + + + align:start position:0% +remind you that we're looking at here an +expression for the squared magnitude + + align:start position:0% +expression for the squared magnitude + + + align:start position:0% +expression for the squared magnitude +function and so we have a 2N here but in + + align:start position:0% +function and so we have a 2N here but in + + + align:start position:0% +function and so we have a 2N here but in +fact n is what corresponds to the order + + align:start position:0% +fact n is what corresponds to the order + + + align:start position:0% +fact n is what corresponds to the order +of the + + align:start position:0% +of the + + + align:start position:0% +of the +filter well if we look at this frequency + + align:start position:0% +filter well if we look at this frequency + + + align:start position:0% +filter well if we look at this frequency +response + + align:start position:0% +response + + + align:start position:0% +response +characteristic we observe that at Omega + + align:start position:0% +characteristic we observe that at Omega + + + align:start position:0% +characteristic we observe that at Omega +equal to zero + + align:start position:0% +equal to zero + + + align:start position:0% +equal to zero +the gain or the magnitude squared is + + align:start position:0% +the gain or the magnitude squared is + + + align:start position:0% +the gain or the magnitude squared is +equal to + + align:start position:0% +equal to + + + align:start position:0% +equal to +Unity at Omega equal to Omega + + align:start position:0% +Unity at Omega equal to Omega + + + align:start position:0% +Unity at Omega equal to Omega +subc the JS of course cancel out and + + align:start position:0% +subc the JS of course cancel out and + + + align:start position:0% +subc the JS of course cancel out and +Omega equal to Omega Sub C we this term + + align:start position:0% +Omega equal to Omega Sub C we this term + + + align:start position:0% +Omega equal to Omega Sub C we this term +then is equal to one and we have for the + + align:start position:0% +then is equal to one and we have for the + + + align:start position:0% +then is equal to one and we have for the +magnitude squared function a half or for + + align:start position:0% +magnitude squared function a half or for + + + align:start position:0% +magnitude squared function a half or for +the magnitude function which is what + + align:start position:0% +the magnitude function which is what + + + align:start position:0% +the magnitude function which is what +we're looking at + + align:start position:0% +we're looking at + + + align:start position:0% +we're looking at +here 1 / the < TK of two so at Omega + + align:start position:0% +here 1 / the < TK of two so at Omega + + + align:start position:0% +here 1 / the < TK of two so at Omega +equal to Omega Sub C an analog + + align:start position:0% +equal to Omega Sub C an analog + + + align:start position:0% +equal to Omega Sub C an analog +Butterworth filter has a magnitude which + + align:start position:0% +Butterworth filter has a magnitude which + + + align:start position:0% +Butterworth filter has a magnitude which +is down by 1 over the < TK of 2 and the + + align:start position:0% +is down by 1 over the < TK of 2 and the + + + align:start position:0% +is down by 1 over the < TK of 2 and the +other important characteristic is that + + align:start position:0% +other important characteristic is that + + + align:start position:0% +other important characteristic is that +the frequency response is a monotonic + + align:start position:0% +the frequency response is a monotonic + + + align:start position:0% +the frequency response is a monotonic +function of capital Omega so that as + + align:start position:0% +function of capital Omega so that as + + + align:start position:0% +function of capital Omega so that as +capital Omega increases from zero to + + align:start position:0% +capital Omega increases from zero to + + + align:start position:0% +capital Omega increases from zero to +Infinity the magnitude or the frequency + + align:start position:0% +Infinity the magnitude or the frequency + + + align:start position:0% +Infinity the magnitude or the frequency +response is a monotonic + + align:start position:0% +response is a monotonic + + + align:start position:0% +response is a monotonic +function well we observe ve that the cut + + align:start position:0% +function well we observe ve that the cut + + + align:start position:0% +function well we observe ve that the cut +off frequency the parameter Omega + + align:start position:0% +off frequency the parameter Omega + + + align:start position:0% +off frequency the parameter Omega +subc adjusts in a sense where we might + + align:start position:0% +subc adjusts in a sense where we might + + + align:start position:0% +subc adjusts in a sense where we might +divide the frequency characteristic into + + align:start position:0% +divide the frequency characteristic into + + + align:start position:0% +divide the frequency characteristic into +pass band transition band and stop band + + align:start position:0% +pass band transition band and stop band + + + align:start position:0% +pass band transition band and stop band +we have another parameter which is the + + align:start position:0% +we have another parameter which is the + + + align:start position:0% +we have another parameter which is the +parameter n the order of the filter and + + align:start position:0% +parameter n the order of the filter and + + + align:start position:0% +parameter n the order of the filter and +basically the effect that the parameter + + align:start position:0% +basically the effect that the parameter + + + align:start position:0% +basically the effect that the parameter +n has is to affect the shape of this + + align:start position:0% +n has is to affect the shape of this + + + align:start position:0% +n has is to affect the shape of this +frequency response in the sense that if + + align:start position:0% +frequency response in the sense that if + + + align:start position:0% +frequency response in the sense that if +capital N is + + align:start position:0% +capital N is + + + align:start position:0% +capital N is +larger the frequency response tends to + + align:start position:0% +larger the frequency response tends to + + + align:start position:0% +larger the frequency response tends to +be flatter longer so that for a larger + + align:start position:0% +be flatter longer so that for a larger + + + align:start position:0% +be flatter longer so that for a larger +nend than what I've drawn with the black + + align:start position:0% +nend than what I've drawn with the black + + + align:start position:0% +nend than what I've drawn with the black +curve the frequency response might look + + align:start position:0% +curve the frequency response might look + + + align:start position:0% +curve the frequency response might look +more like this and then drop off + + align:start position:0% +more like this and then drop off + + + align:start position:0% +more like this and then drop off +sharper whereas if capital N is smaller + + align:start position:0% +sharper whereas if capital N is smaller + + + align:start position:0% +sharper whereas if capital N is smaller +then it will be less flat in the pass + + align:start position:0% +then it will be less flat in the pass + + + align:start position:0% +then it will be less flat in the pass +band and drop off more slowly + + align:start position:0% +band and drop off more slowly + + + align:start position:0% +band and drop off more slowly +so in fact the way that I've drawn it + + align:start position:0% +so in fact the way that I've drawn it + + + align:start position:0% +so in fact the way that I've drawn it +here this is the behavior of the + + align:start position:0% +here this is the behavior of the + + + align:start position:0% +here this is the behavior of the +frequency response curve as the + + align:start position:0% +frequency response curve as the + + + align:start position:0% +frequency response curve as the +parameter capital + + align:start position:0% +parameter capital + + + align:start position:0% +parameter capital +N + + align:start position:0% +N + + + align:start position:0% +N +increases so the higher the order of the + + align:start position:0% +increases so the higher the order of the + + + align:start position:0% +increases so the higher the order of the +filter the sharper the drop from what we + + align:start position:0% +filter the sharper the drop from what we + + + align:start position:0% +filter the sharper the drop from what we +could consider as a pass band region + + align:start position:0% +could consider as a pass band region + + + align:start position:0% +could consider as a pass band region +into a stop band region and obviously + + align:start position:0% +into a stop band region and obviously + + + align:start position:0% +into a stop band region and obviously +then the sharper the filter we want the + + align:start position:0% +then the sharper the filter we want the + + + align:start position:0% +then the sharper the filter we want the +higher order filter we would + + align:start position:0% +higher order filter we would + + + align:start position:0% +higher order filter we would +design now to look at the pole zero + + align:start position:0% +design now to look at the pole zero + + + align:start position:0% +design now to look at the pole zero +pattern or the zero pattern really of + + align:start position:0% +pattern or the zero pattern really of + + + align:start position:0% +pattern or the zero pattern really of +the Butterworth + + align:start position:0% +the Butterworth + + + align:start position:0% +the Butterworth +filter we can convert this + + align:start position:0% +filter we can convert this + + + align:start position:0% +filter we can convert this +expression into an expression + + align:start position:0% +expression into an expression + + + align:start position:0% +expression into an expression +relating the magnitude squared function + + align:start position:0% +relating the magnitude squared function + + + align:start position:0% +relating the magnitude squared function +expressed in terms of the llast + + align:start position:0% +expressed in terms of the llast + + + align:start position:0% +expressed in terms of the llast +transform variable s and so this + + align:start position:0% +transform variable s and so this + + + align:start position:0% +transform variable s and so this +expression corresponds to the product H + + align:start position:0% +expression corresponds to the product H + + + align:start position:0% +expression corresponds to the product H +sub a of s * H sub a of minus s + + align:start position:0% +sub a of s * H sub a of minus s + + + align:start position:0% +sub a of s * H sub a of minus s +evaluated at s = j + + align:start position:0% +evaluated at s = j + + + align:start position:0% +evaluated at s = j +Omega in which case the J Omega is what + + align:start position:0% +Omega in which case the J Omega is what + + + align:start position:0% +Omega in which case the J Omega is what +corresponds to S and so H sub of s * H + + align:start position:0% +corresponds to S and so H sub of s * H + + + align:start position:0% +corresponds to S and so H sub of s * H +sub a of minus s is of the form 1/ 1 + S + + align:start position:0% +sub a of minus s is of the form 1/ 1 + S + + + align:start position:0% +sub a of minus s is of the form 1/ 1 + S +/ J Omega + + align:start position:0% +/ J Omega + + + align:start position:0% +/ J Omega +subc raised to the 2 N + + align:start position:0% +subc raised to the 2 N + + + align:start position:0% +subc raised to the 2 N +power well what we re recognize is that + + align:start position:0% +power well what we re recognize is that + + + align:start position:0% +power well what we re recognize is that +this + + align:start position:0% +this + + + align:start position:0% +this +expression has poles if we solve this + + align:start position:0% +expression has poles if we solve this + + + align:start position:0% +expression has poles if we solve this +equation this expression has poles at of + + align:start position:0% +equation this expression has poles at of + + + align:start position:0% +equation this expression has poles at of +course the roots of the denominator + + align:start position:0% +course the roots of the denominator + + + align:start position:0% +course the roots of the denominator +polinomial or at s equal to minus1 to + + align:start position:0% +polinomial or at s equal to minus1 to + + + align:start position:0% +polinomial or at s equal to minus1 to +the 1/ 2N * J Omega Sub C that's simply + + align:start position:0% +the 1/ 2N * J Omega Sub C that's simply + + + align:start position:0% +the 1/ 2N * J Omega Sub C that's simply +solving the equation with this + + align:start position:0% +solving the equation with this + + + align:start position:0% +solving the equation with this +denominator polinomial equal to + + align:start position:0% +denominator polinomial equal to + + + align:start position:0% +denominator polinomial equal to +zero well we can see more spe + + align:start position:0% +zero well we can see more spe + + + align:start position:0% +zero well we can see more spe +specifically where these poles lie in + + align:start position:0% +specifically where these poles lie in + + + align:start position:0% +specifically where these poles lie in +the S + + align:start position:0% +the S + + + align:start position:0% +the S +plane by recognizing that these are the + + align:start position:0% +plane by recognizing that these are the + + + align:start position:0% +plane by recognizing that these are the +2 N roots of + + align:start position:0% +2 N roots of + + + align:start position:0% +2 N roots of +minus1 and then we have a j which + + align:start position:0% +minus1 and then we have a j which + + + align:start position:0% +minus1 and then we have a j which +corresponds to e to J Pi uh e to the J + + align:start position:0% +corresponds to e to J Pi uh e to the J + + + align:start position:0% +corresponds to e to J Pi uh e to the J +pi/ 2 so we can rewrite this expression + + align:start position:0% +pi/ 2 so we can rewrite this expression + + + align:start position:0% +pi/ 2 so we can rewrite this expression +for the poles as + + align:start position:0% +for the poles as + + + align:start position:0% +for the poles as +s equal to e to J pi/ 2X + + align:start position:0% + + + + align:start position:0% + +that's that's one of the roots of minus1 + + align:start position:0% +that's that's one of the roots of minus1 + + + align:start position:0% +that's that's one of the roots of minus1 +plus K * 2 pi where K is an integer this + + align:start position:0% +plus K * 2 pi where K is an integer this + + + align:start position:0% +plus K * 2 pi where K is an integer this +generates the roots of + + align:start position:0% +generates the roots of + + + align:start position:0% +generates the roots of +minus1 we need to multiply by J and we + + align:start position:0% +minus1 we need to multiply by J and we + + + align:start position:0% +minus1 we need to multiply by J and we +can do that by multiplying by e to the J + + align:start position:0% +can do that by multiplying by e to the J + + + align:start position:0% +can do that by multiplying by e to the J +Pi / 2 which is equal to J times Omega + + align:start position:0% +Pi / 2 which is equal to J times Omega + + + align:start position:0% +Pi / 2 which is equal to J times Omega +Sub C which is the cutof frequency + + align:start position:0% +Sub C which is the cutof frequency + + + align:start position:0% +Sub C which is the cutof frequency +parameter for the Butterworth + + align:start position:0% +parameter for the Butterworth + + + align:start position:0% +parameter for the Butterworth +filter so this then specifies where the + + align:start position:0% +filter so this then specifies where the + + + align:start position:0% +filter so this then specifies where the +pole locations are for the Butterworth + + align:start position:0% +pole locations are for the Butterworth + + + align:start position:0% +pole locations are for the Butterworth +filter for example if we consider the + + align:start position:0% +filter for example if we consider the + + + align:start position:0% +filter for example if we consider the +case let's say with n equal to + + align:start position:0% +case let's say with n equal to + + + align:start position:0% +case let's say with n equal to +3 K let's say equal to + + align:start position:0% +3 K let's say equal to + + + align:start position:0% +3 K let's say equal to +zero that says then that we have a poll + + align:start position:0% +zero that says then that we have a poll + + + align:start position:0% +zero that says then that we have a poll +at e to the J Pi / 6 e to the J pi/ + + align:start position:0% +at e to the J Pi / 6 e to the J pi/ + + + align:start position:0% +at e to the J Pi / 6 e to the J pi/ +6 time e to J Pi / 2 in other words we + + align:start position:0% +6 time e to J Pi / 2 in other words we + + + align:start position:0% +6 time e to J Pi / 2 in other words we +have a pole in the S plane at an angle + + align:start position:0% +have a pole in the S plane at an angle + + + align:start position:0% +have a pole in the S plane at an angle +of < / 6 + piun / 2 which corresponds to + + align:start position:0% +of < / 6 + piun / 2 which corresponds to + + + align:start position:0% +of < / 6 + piun / 2 which corresponds to +this + + align:start position:0% +this + + + align:start position:0% +this +location then we'll have poles + + align:start position:0% +location then we'll have poles + + + align:start position:0% +location then we'll have poles +distributed in angle around a circle in + + align:start position:0% +distributed in angle around a circle in + + + align:start position:0% +distributed in angle around a circle in +the S plane distributed in an angle + + align:start position:0% +the S plane distributed in an angle + + + align:start position:0% +the S plane distributed in an angle +where the angular spacing is pi over3 + + align:start position:0% +where the angular spacing is pi over3 + + + align:start position:0% +where the angular spacing is pi over3 +the pi over3 arising from a + + align:start position:0% +the pi over3 arising from a + + + align:start position:0% +the pi over3 arising from a +consideration of 2 pi k / 2N where in + + align:start position:0% +consideration of 2 pi k / 2N where in + + + align:start position:0% +consideration of 2 pi k / 2N where in +this case n is equal to + + align:start position:0% +this case n is equal to + + + align:start position:0% +this case n is equal to +6 so these poles are + + align:start position:0% +6 so these poles are + + + align:start position:0% +6 so these poles are +distributed equally spaced an angle on a + + align:start position:0% +distributed equally spaced an angle on a + + + align:start position:0% +distributed equally spaced an angle on a +circle in the S plane for n equal to 3 + + align:start position:0% +circle in the S plane for n equal to 3 + + + align:start position:0% +circle in the S plane for n equal to 3 +the angular spacing is pi over 3 for k + + align:start position:0% +the angular spacing is pi over 3 for k + + + align:start position:0% +the angular spacing is pi over 3 for k +equal to zero that first pole + + align:start position:0% +equal to zero that first pole + + + align:start position:0% +equal to zero that first pole +corresponds to this one and then we + + align:start position:0% +corresponds to this one and then we + + + align:start position:0% +corresponds to this one and then we +continue + + align:start position:0% +continue + + + align:start position:0% +continue +around now these are poles distributed + + align:start position:0% +around now these are poles distributed + + + align:start position:0% +around now these are poles distributed +on a circle which tends to look like the + + align:start position:0% +on a circle which tends to look like the + + + align:start position:0% +on a circle which tends to look like the +Z plane + + align:start position:0% +Z plane + + + align:start position:0% +Z plane +but I stress that what we're talking + + align:start position:0% +but I stress that what we're talking + + + align:start position:0% +but I stress that what we're talking +about here is the S plane in particular + + align:start position:0% +about here is the S plane in particular + + + align:start position:0% +about here is the S plane in particular +we're talking about the analog frequency + + align:start position:0% +we're talking about the analog frequency + + + align:start position:0% +we're talking about the analog frequency +response design that is the class of + + align:start position:0% +response design that is the class of + + + align:start position:0% +response design that is the class of +analog Butterworth filters which we're + + align:start position:0% +analog Butterworth filters which we're + + + align:start position:0% +analog Butterworth filters which we're +then going to map to digital filters so + + align:start position:0% +then going to map to digital filters so + + + align:start position:0% +then going to map to digital filters so +this is a circle in the S plane it's + + align:start position:0% +this is a circle in the S plane it's + + + align:start position:0% +this is a circle in the S plane it's +often referred to as the Butterworth + + align:start position:0% +often referred to as the Butterworth + + + align:start position:0% +often referred to as the Butterworth +Circle and it has a radius which is + + align:start position:0% +Circle and it has a radius which is + + + align:start position:0% +Circle and it has a radius which is +equal to Omega + + align:start position:0% +equal to Omega + + + align:start position:0% +equal to Omega +subc in designing + + align:start position:0% +subc in designing + + + align:start position:0% +subc in designing +a an analog Butterworth filter then the + + align:start position:0% +a an analog Butterworth filter then the + + + align:start position:0% +a an analog Butterworth filter then the +procedure is to appropriately choose + + align:start position:0% +procedure is to appropriately choose + + + align:start position:0% +procedure is to appropriately choose +this the parameters Omega subc and + + align:start position:0% +this the parameters Omega subc and + + + align:start position:0% +this the parameters Omega subc and +capital N those are the parameters of + + align:start position:0% +capital N those are the parameters of + + + align:start position:0% +capital N those are the parameters of +the analog Butterworth + + align:start position:0% +the analog Butterworth + + + align:start position:0% +the analog Butterworth +filter and + + align:start position:0% +filter and + + + align:start position:0% +filter and +then + + align:start position:0% +then + + + align:start position:0% +then +from the poles distributed on the + + align:start position:0% +from the poles distributed on the + + + align:start position:0% +from the poles distributed on the +Butterworth Circle this gives us the + + align:start position:0% +Butterworth Circle this gives us the + + + align:start position:0% +Butterworth Circle this gives us the +pole locations for the product H sub a + + align:start position:0% +pole locations for the product H sub a + + + align:start position:0% +pole locations for the product H sub a +of x s time H sub a of minus + + align:start position:0% +of x s time H sub a of minus + + + align:start position:0% +of x s time H sub a of minus +s we can then simply + + align:start position:0% +s we can then simply + + + align:start position:0% +s we can then simply +associate with the transfer function H + + align:start position:0% +associate with the transfer function H + + + align:start position:0% +associate with the transfer function H +sub a of s the poles in the left half + + align:start position:0% +sub a of s the poles in the left half + + + align:start position:0% +sub a of s the poles in the left half +plane to generate a stable filter and + + align:start position:0% +plane to generate a stable filter and + + + align:start position:0% +plane to generate a stable filter and +then the ones which are contributed by + + align:start position:0% +then the ones which are contributed by + + + align:start position:0% +then the ones which are contributed by +the factor H Suba of minus s are the + + align:start position:0% +the factor H Suba of minus s are the + + + align:start position:0% +the factor H Suba of minus s are the +corresponding image poles in the right + + align:start position:0% +corresponding image poles in the right + + + align:start position:0% +corresponding image poles in the right +half + + align:start position:0% +half + + + align:start position:0% +half +plane procedure then is to design a + + align:start position:0% +plane procedure then is to design a + + + align:start position:0% +plane procedure then is to design a +squared magnitude + + align:start position:0% +squared magnitude + + + align:start position:0% +squared magnitude +function talking about a Butterworth + + align:start position:0% +function talking about a Butterworth + + + align:start position:0% +function talking about a Butterworth +filter we choose these parameters Omega + + align:start position:0% +filter we choose these parameters Omega + + + align:start position:0% +filter we choose these parameters Omega +subc and N that tells us where the poles + + align:start position:0% +subc and N that tells us where the poles + + + align:start position:0% +subc and N that tells us where the poles +are located on the Butterworth + + align:start position:0% +are located on the Butterworth + + + align:start position:0% +are located on the Butterworth +circle from the pole locations for the + + align:start position:0% +circle from the pole locations for the + + + align:start position:0% +circle from the pole locations for the +squared magnitude function then we can + + align:start position:0% +squared magnitude function then we can + + + align:start position:0% +squared magnitude function then we can +factor that into H sub a of s * H sub a + + align:start position:0% +factor that into H sub a of s * H sub a + + + align:start position:0% +factor that into H sub a of s * H sub a +of minus s by choosing the poles that + + align:start position:0% +of minus s by choosing the poles that + + + align:start position:0% +of minus s by choosing the poles that +fall in the left half plane to give us a + + align:start position:0% +fall in the left half plane to give us a + + + align:start position:0% +fall in the left half plane to give us a +causal stable analog filter + + align:start position:0% + + + + align:start position:0% + +all right well that is an analog filter + + align:start position:0% +all right well that is an analog filter + + + align:start position:0% +all right well that is an analog filter +what we would like to talk about is the + + align:start position:0% +what we would like to talk about is the + + + align:start position:0% +what we would like to talk about is the +design of a digital filter and the + + align:start position:0% +design of a digital filter and the + + + align:start position:0% +design of a digital filter and the +procedure that we're going to go through + + align:start position:0% +procedure that we're going to go through + + + align:start position:0% +procedure that we're going to go through +is to choose a set of specs for the + + align:start position:0% +is to choose a set of specs for the + + + align:start position:0% +is to choose a set of specs for the +digital + + align:start position:0% +digital + + + align:start position:0% +digital +filter and then decide on what the + + align:start position:0% +filter and then decide on what the + + + align:start position:0% +filter and then decide on what the +corresponding specifications should be + + align:start position:0% +corresponding specifications should be + + + align:start position:0% +corresponding specifications should be +for the analog filter depending on + + align:start position:0% +for the analog filter depending on + + + align:start position:0% +for the analog filter depending on +whether we're using impulse and variance + + align:start position:0% +whether we're using impulse and variance + + + align:start position:0% +whether we're using impulse and variance +or the bilinear + + align:start position:0% +or the bilinear + + + align:start position:0% +or the bilinear +transformation the design the analog + + align:start position:0% +transformation the design the analog + + + align:start position:0% +transformation the design the analog +filter and then map the result to a + + align:start position:0% +filter and then map the result to a + + + align:start position:0% +filter and then map the result to a +digital filter using one of those two + + align:start position:0% +digital filter using one of those two + + + align:start position:0% +digital filter using one of those two +techniques so let's choose a set of + + align:start position:0% +techniques so let's choose a set of + + + align:start position:0% +techniques so let's choose a set of +digital filter + + align:start position:0% +digital filter + + + align:start position:0% +digital filter +specifications for a digital low pass + + align:start position:0% +specifications for a digital low pass + + + align:start position:0% +specifications for a digital low pass +filter with a pass band which occurs for + + align:start position:0% +filter with a pass band which occurs for + + + align:start position:0% +filter with a pass band which occurs for +frequencies now in the digital domain + + align:start position:0% +frequencies now in the digital domain + + + align:start position:0% +frequencies now in the digital domain +for frequencies below 02 pi + + align:start position:0% +for frequencies below 02 pi + + + align:start position:0% +for frequencies below 02 pi +and a stop band region that occurs for + + align:start position:0% +and a stop band region that occurs for + + + align:start position:0% +and a stop band region that occurs for +frequencies greater than 3 pi and the + + align:start position:0% +frequencies greater than 3 pi and the + + + align:start position:0% +frequencies greater than 3 pi and the +transition band then of course is the + + align:start position:0% +transition band then of course is the + + + align:start position:0% +transition band then of course is the +region in between + + align:start position:0% +region in between + + + align:start position:0% +region in between +those so we would like to design a + + align:start position:0% +those so we would like to design a + + + align:start position:0% +those so we would like to design a +digital filter which stays within some + + align:start position:0% +digital filter which stays within some + + + align:start position:0% +digital filter which stays within some +limits in this pass band region drops + + align:start position:0% +limits in this pass band region drops + + + align:start position:0% +limits in this pass band region drops +below Su limit Delta Subs in the stop + + align:start position:0% +below Su limit Delta Subs in the stop + + + align:start position:0% +below Su limit Delta Subs in the stop +band region and will choose as the + + align:start position:0% +band region and will choose as the + + + align:start position:0% +band region and will choose as the +limits in the pass band Unity for the + + align:start position:0% +limits in the pass band Unity for the + + + align:start position:0% +limits in the pass band Unity for the +upper limit and 1 minus Delta sub for + + align:start position:0% +upper limit and 1 minus Delta sub for + + + align:start position:0% +upper limit and 1 minus Delta sub for +the lower limit where Delta sub 1 minus + + align:start position:0% +the lower limit where Delta sub 1 minus + + + align:start position:0% +the lower limit where Delta sub 1 minus +Delta subp might not and in fact it + + align:start position:0% +Delta subp might not and in fact it + + + align:start position:0% +Delta subp might not and in fact it +won't turn out to be 1 over theare < TK + + align:start position:0% +won't turn out to be 1 over theare < TK + + + align:start position:0% +won't turn out to be 1 over theare < TK +of two in other words this cut off + + align:start position:0% +of two in other words this cut off + + + align:start position:0% +of two in other words this cut off +frequency will not necessarily + + align:start position:0% +frequency will not necessarily + + + align:start position:0% +frequency will not necessarily +correspond to the parameter Omega subc + + align:start position:0% +correspond to the parameter Omega subc + + + align:start position:0% +correspond to the parameter Omega subc +for the Butterworth + + align:start position:0% +for the Butterworth + + + align:start position:0% +for the Butterworth +filter all right well so let's choose a + + align:start position:0% +filter all right well so let's choose a + + + align:start position:0% +filter all right well so let's choose a +set of + + align:start position:0% +set of + + + align:start position:0% +set of +specifications the ones that I've chosen + + align:start position:0% +specifications the ones that I've chosen + + + align:start position:0% +specifications the ones that I've chosen +are the requirement that the frequency + + align:start position:0% +are the requirement that the frequency + + + align:start position:0% +are the requirement that the frequency +response + + align:start position:0% +response + + + align:start position:0% +response +characteristic be within 1 DB of unity + + align:start position:0% +characteristic be within 1 DB of unity + + + align:start position:0% +characteristic be within 1 DB of unity +in the pass band in other words the + + align:start position:0% +in the pass band in other words the + + + align:start position:0% +in the pass band in other words the +requirement that 1 minus Delta subp be + + align:start position:0% +requirement that 1 minus Delta subp be + + + align:start position:0% +requirement that 1 minus Delta subp be +greater than or equal to minus1 DB so + + align:start position:0% +greater than or equal to minus1 DB so + + + align:start position:0% +greater than or equal to minus1 DB so +this deviation must be less than 1 + + align:start position:0% +this deviation must be less than 1 + + + align:start position:0% +this deviation must be less than 1 +DB and then the requirement that in the + + align:start position:0% +DB and then the requirement that in the + + + align:start position:0% +DB and then the requirement that in the +stop band The fre quency response + + align:start position:0% +stop band The fre quency response + + + align:start position:0% +stop band The fre quency response +characteristic is + + align:start position:0% +characteristic is + + + align:start position:0% +characteristic is +below 15 DB minus 15 DB in other words + + align:start position:0% +below 15 DB minus 15 DB in other words + + + align:start position:0% +below 15 DB minus 15 DB in other words +the stop band attenuation for + + align:start position:0% +the stop band attenuation for + + + align:start position:0% +the stop band attenuation for +frequencies greater than. 3 Pi is + + align:start position:0% +frequencies greater than. 3 Pi is + + + align:start position:0% +frequencies greater than. 3 Pi is +greater than minus 15 DB it's further + + align:start position:0% +greater than minus 15 DB it's further + + + align:start position:0% +greater than minus 15 DB it's further +down than minus5 DB so Delta Subs is + + align:start position:0% +down than minus5 DB so Delta Subs is + + + align:start position:0% +down than minus5 DB so Delta Subs is +less than or equal to minus5 + + align:start position:0% +less than or equal to minus5 + + + align:start position:0% +less than or equal to minus5 +DB the one other specification that + + align:start position:0% +DB the one other specification that + + + align:start position:0% +DB the one other specification that +we'll impose or in fact it's really a + + align:start position:0% +we'll impose or in fact it's really a + + + align:start position:0% +we'll impose or in fact it's really a +consequence that will result from using + + align:start position:0% +consequence that will result from using + + + align:start position:0% +consequence that will result from using +a Butterworth filter is the fact that + + align:start position:0% +a Butterworth filter is the fact that + + + align:start position:0% +a Butterworth filter is the fact that +the frequency characteristic is + + align:start position:0% +the frequency characteristic is + + + align:start position:0% +the frequency characteristic is +monotonic so we have the pass band Edge + + align:start position:0% +monotonic so we have the pass band Edge + + + align:start position:0% +monotonic so we have the pass band Edge +the stop band Edge the pass band Ripple + + align:start position:0% +the stop band Edge the pass band Ripple + + + align:start position:0% +the stop band Edge the pass band Ripple +or deviation and the stop band rippler + + align:start position:0% +or deviation and the stop band rippler + + + align:start position:0% +or deviation and the stop band rippler +deviation and we can of course rewrite + + align:start position:0% +deviation and we can of course rewrite + + + align:start position:0% +deviation and we can of course rewrite +these + + align:start position:0% +these + + + align:start position:0% +these +specifications in terms of requirements + + align:start position:0% +specifications in terms of requirements + + + align:start position:0% +specifications in terms of requirements +on the trans for function or frequency + + align:start position:0% +on the trans for function or frequency + + + align:start position:0% +on the trans for function or frequency +response the magnitude of the frequency + + align:start position:0% +response the magnitude of the frequency + + + align:start position:0% +response the magnitude of the frequency +response the requirement that the + + align:start position:0% +response the requirement that the + + + align:start position:0% +response the requirement that the +deviation be less than 1 DB in the pass + + align:start position:0% +deviation be less than 1 DB in the pass + + + align:start position:0% +deviation be less than 1 DB in the pass +band is the requirement then the 20 log + + align:start position:0% +band is the requirement then the 20 log + + + align:start position:0% +band is the requirement then the 20 log +to the base 10 of the magnitude of the + + align:start position:0% +to the base 10 of the magnitude of the + + + align:start position:0% +to the base 10 of the magnitude of the +frequency response that's the deviation + + align:start position:0% +frequency response that's the deviation + + + align:start position:0% +frequency response that's the deviation +DB be greater than or equal to + + align:start position:0% +DB be greater than or equal to + + + align:start position:0% +DB be greater than or equal to +minus1 or that the magnitude be greater + + align:start position:0% +minus1 or that the magnitude be greater + + + align:start position:0% +minus1 or that the magnitude be greater +than equal to + + align:start position:0% + + + + align:start position:0% + +10-05 and of course we want it also to + + align:start position:0% +10-05 and of course we want it also to + + + align:start position:0% +10-05 and of course we want it also to +be less than unity and that's an implied + + align:start position:0% +be less than unity and that's an implied + + + align:start position:0% +be less than unity and that's an implied +condition so it must be less than unity + + align:start position:0% +condition so it must be less than unity + + + align:start position:0% +condition so it must be less than unity +and must be greater than or equal to + + align:start position:0% +and must be greater than or equal to + + + align:start position:0% +and must be greater than or equal to +10us 05 for frequencies from zero to 0 2 + + align:start position:0% +10us 05 for frequencies from zero to 0 2 + + + align:start position:0% +10us 05 for frequencies from zero to 0 2 +pi so in particular since it's monotonic + + align:start position:0% +pi so in particular since it's monotonic + + + align:start position:0% +pi so in particular since it's monotonic +we'll impose that condition at the + + align:start position:0% +we'll impose that condition at the + + + align:start position:0% +we'll impose that condition at the +frequency 2 pi corresponding to the end + + align:start position:0% +frequency 2 pi corresponding to the end + + + align:start position:0% +frequency 2 pi corresponding to the end +of the stop band and the beginning of + + align:start position:0% +of the stop band and the beginning of + + + align:start position:0% +of the stop band and the beginning of +the transition + + align:start position:0% +the transition + + + align:start position:0% +the transition +band the second condition that we impose + + align:start position:0% +band the second condition that we impose + + + align:start position:0% +band the second condition that we impose +is the condition that by the time we get + + align:start position:0% +is the condition that by the time we get + + + align:start position:0% +is the condition that by the time we get +to Omega equal to 3 + + align:start position:0% +to Omega equal to 3 + + + align:start position:0% +to Omega equal to 3 +Pi we would like the frequency response + + align:start position:0% +Pi we would like the frequency response + + + align:start position:0% +Pi we would like the frequency response +to be down at least 15 DB and more if + + align:start position:0% +to be down at least 15 DB and more if + + + align:start position:0% +to be down at least 15 DB and more if +possible but the condition is that the + + align:start position:0% +possible but the condition is that the + + + align:start position:0% +possible but the condition is that the +20 log to the base 10 of the magnitude + + align:start position:0% +20 log to the base 10 of the magnitude + + + align:start position:0% +20 log to the base 10 of the magnitude +at Omega equal to3 3 Pi must be less + + align:start position:0% +at Omega equal to3 3 Pi must be less + + + align:start position:0% +at Omega equal to3 3 Pi must be less +than or equal to + + align:start position:0% +than or equal to + + + align:start position:0% +than or equal to +minus5 so this says we must be further + + align:start position:0% +minus5 so this says we must be further + + + align:start position:0% +minus5 so this says we must be further +down than 15 DB or we can translate that + + align:start position:0% +down than 15 DB or we can translate that + + + align:start position:0% +down than 15 DB or we can translate that +into a condition on the magnitude so + + align:start position:0% +into a condition on the magnitude so + + + align:start position:0% +into a condition on the magnitude so +that the magnitude of that frequency is + + align:start position:0% +that the magnitude of that frequency is + + + align:start position:0% +that the magnitude of that frequency is +less than or equal to 10 minus. + + align:start position:0% + + + + align:start position:0% + +75 well let's consider two we want to + + align:start position:0% +75 well let's consider two we want to + + + align:start position:0% +75 well let's consider two we want to +consider two design procedures let's + + align:start position:0% +consider two design procedures let's + + + align:start position:0% +consider two design procedures let's +first consider the impulse and variant + + align:start position:0% +first consider the impulse and variant + + + align:start position:0% +first consider the impulse and variant +design procedure in which case we would + + align:start position:0% +design procedure in which case we would + + + align:start position:0% +design procedure in which case we would +like to convert these + + align:start position:0% +like to convert these + + + align:start position:0% +like to convert these +specifications on the digital + + align:start position:0% +specifications on the digital + + + align:start position:0% +specifications on the digital +filter + + align:start position:0% +filter + + + align:start position:0% +filter +to corresponding specifications on the + + align:start position:0% +to corresponding specifications on the + + + align:start position:0% +to corresponding specifications on the +analog + + align:start position:0% +analog + + + align:start position:0% +analog +filter now we know that from discussions + + align:start position:0% +filter now we know that from discussions + + + align:start position:0% +filter now we know that from discussions +that we've had + + align:start position:0% +that we've had + + + align:start position:0% +that we've had +previously that if we have an analog + + align:start position:0% +previously that if we have an analog + + + align:start position:0% +previously that if we have an analog +frequency response and we apply impulse + + align:start position:0% +frequency response and we apply impulse + + + align:start position:0% +frequency response and we apply impulse +and variance to the impulse response the + + align:start position:0% +and variance to the impulse response the + + + align:start position:0% +and variance to the impulse response the +digital frequency response consists of + + align:start position:0% +digital frequency response consists of + + + align:start position:0% +digital frequency response consists of +the analog frequency response scaled in + + align:start position:0% +the analog frequency response scaled in + + + align:start position:0% +the analog frequency response scaled in +frequency so that Capital Omega is equal + + align:start position:0% +frequency so that Capital Omega is equal + + + align:start position:0% +frequency so that Capital Omega is equal +to little Omega / capital + + align:start position:0% +to little Omega / capital + + + align:start position:0% +to little Omega / capital +T and then that scaled replica of H Suba + + align:start position:0% +T and then that scaled replica of H Suba + + + align:start position:0% +T and then that scaled replica of H Suba +added to itself delayed by little Omega + + align:start position:0% +added to itself delayed by little Omega + + + align:start position:0% +added to itself delayed by little Omega +equal to 2 pi 4 Pi Etc that is multiples + + align:start position:0% +equal to 2 pi 4 Pi Etc that is multiples + + + align:start position:0% +equal to 2 pi 4 Pi Etc that is multiples +of 2 + + align:start position:0% +of 2 + + + align:start position:0% +of 2 +pi so that means then that the analog + + align:start position:0% +pi so that means then that the analog + + + align:start position:0% +pi so that means then that the analog +filter will that the digital filter is + + align:start position:0% +filter will that the digital filter is + + + align:start position:0% +filter will that the digital filter is +scaled repeated replicas of the analog + + align:start position:0% +scaled repeated replicas of the analog + + + align:start position:0% +scaled repeated replicas of the analog +filter and so we would choose the analog + + align:start position:0% +filter and so we would choose the analog + + + align:start position:0% +filter and so we would choose the analog +filter to have similar specifications to + + align:start position:0% +filter to have similar specifications to + + + align:start position:0% +filter to have similar specifications to +the digital + + align:start position:0% +the digital + + + align:start position:0% +the digital +filter but with the corresponding + + align:start position:0% +filter but with the corresponding + + + align:start position:0% +filter but with the corresponding +frequency parameters dictated by this + + align:start position:0% +frequency parameters dictated by this + + + align:start position:0% +frequency parameters dictated by this +transformation Capital Omega equal to + + align:start position:0% +transformation Capital Omega equal to + + + align:start position:0% +transformation Capital Omega equal to +little Omega / capital t + + align:start position:0% + + + + align:start position:0% + +well that of course neglects aliasing + + align:start position:0% +well that of course neglects aliasing + + + align:start position:0% +well that of course neglects aliasing +and in fact as we go through the impulse + + align:start position:0% +and in fact as we go through the impulse + + + align:start position:0% +and in fact as we go through the impulse +invariant design will initially neglect + + align:start position:0% +invariant design will initially neglect + + + align:start position:0% +invariant design will initially neglect +aliasing and uh a rationale for doing + + align:start position:0% +aliasing and uh a rationale for doing + + + align:start position:0% +aliasing and uh a rationale for doing +this or a reason why in fact it's not + + align:start position:0% +this or a reason why in fact it's not + + + align:start position:0% +this or a reason why in fact it's not +unreasonable to do that will emerge as + + align:start position:0% +unreasonable to do that will emerge as + + + align:start position:0% +unreasonable to do that will emerge as +we go through the example so for the + + align:start position:0% +we go through the example so for the + + + align:start position:0% +we go through the example so for the +time being in fact we're going to + + align:start position:0% +time being in fact we're going to + + + align:start position:0% +time being in fact we're going to +neglect + + align:start position:0% +neglect + + + align:start position:0% +neglect +alosine so that we'll think of the + + align:start position:0% +alosine so that we'll think of the + + + align:start position:0% +alosine so that we'll think of the +analog and digital frequency responses + + align:start position:0% +analog and digital frequency responses + + + align:start position:0% +analog and digital frequency responses +as simply related by the substitution of + + align:start position:0% +as simply related by the substitution of + + + align:start position:0% +as simply related by the substitution of +frequency variable Capital Omega equal + + align:start position:0% +frequency variable Capital Omega equal + + + align:start position:0% +frequency variable Capital Omega equal +to little Omega divided capital + + align:start position:0% +to little Omega divided capital + + + align:start position:0% +to little Omega divided capital +T well that leads us + + align:start position:0% +T well that leads us + + + align:start position:0% +T well that leads us +then to the + + align:start position:0% +then to the + + + align:start position:0% +then to the +analog frequency response which I've + + align:start position:0% +analog frequency response which I've + + + align:start position:0% +analog frequency response which I've +depicted + + align:start position:0% +depicted + + + align:start position:0% +depicted +here we had a factor of 1 over capital T + + align:start position:0% +here we had a factor of 1 over capital T + + + align:start position:0% +here we had a factor of 1 over capital T +in the + + align:start position:0% +in the + + + align:start position:0% +in the +amplitude of this + + align:start position:0% +amplitude of this + + + align:start position:0% +amplitude of this +expression so for the digital filter to + + align:start position:0% +expression so for the digital filter to + + + align:start position:0% +expression so for the digital filter to +result with an amplitude of unity at DC + + align:start position:0% +result with an amplitude of unity at DC + + + align:start position:0% +result with an amplitude of unity at DC +we would scale the analog frequency + + align:start position:0% +we would scale the analog frequency + + + align:start position:0% +we would scale the analog frequency +response by capital + + align:start position:0% +response by capital + + + align:start position:0% +response by capital +T so the + + align:start position:0% +T so the + + + align:start position:0% +T so the +important values then in capital Omega + + align:start position:0% +important values then in capital Omega + + + align:start position:0% +important values then in capital Omega +are the ones corresponding to little + + align:start position:0% +are the ones corresponding to little + + + align:start position:0% +are the ones corresponding to little +Omega equal to0 2 + + align:start position:0% +Omega equal to0 2 + + + align:start position:0% +Omega equal to0 2 +pi or since Capital Omega is equal to + + align:start position:0% +pi or since Capital Omega is equal to + + + align:start position:0% +pi or since Capital Omega is equal to +little Omega / capital t we have a pass + + align:start position:0% +little Omega / capital t we have a pass + + + align:start position:0% +little Omega / capital t we have a pass +band Edge occurring at cap Omega equal + + align:start position:0% +band Edge occurring at cap Omega equal + + + align:start position:0% +band Edge occurring at cap Omega equal +to0 2 pi over capital T and A stop band + + align:start position:0% +to0 2 pi over capital T and A stop band + + + align:start position:0% +to0 2 pi over capital T and A stop band +Edge equal to 3 pi over capital + + align:start position:0% +Edge equal to 3 pi over capital + + + align:start position:0% +Edge equal to 3 pi over capital +T at this pass band Edge according to + + align:start position:0% +T at this pass band Edge according to + + + align:start position:0% +T at this pass band Edge according to +the specifications on the digital filter + + align:start position:0% +the specifications on the digital filter + + + align:start position:0% +the specifications on the digital filter +that we want we would like the frequency + + align:start position:0% +that we want we would like the frequency + + + align:start position:0% +that we want we would like the frequency +response for frequencies below this in + + align:start position:0% +response for frequencies below this in + + + align:start position:0% +response for frequencies below this in +other words in the pass band to be + + align:start position:0% +other words in the pass band to be + + + align:start position:0% +other words in the pass band to be +between capital t and capital T * 10us + + align:start position:0% +between capital t and capital T * 10us + + + align:start position:0% +between capital t and capital T * 10us +05 that's the guarantee that we have + + align:start position:0% +05 that's the guarantee that we have + + + align:start position:0% +05 that's the guarantee that we have +less than 1 DB Ripple in the pass band + + align:start position:0% +less than 1 DB Ripple in the pass band + + + align:start position:0% +less than 1 DB Ripple in the pass band +and for frequencies greater than 3 Pi we + + align:start position:0% +and for frequencies greater than 3 Pi we + + + align:start position:0% +and for frequencies greater than 3 Pi we +would like to be below capital T * 10us + + align:start position:0% +would like to be below capital T * 10us + + + align:start position:0% +would like to be below capital T * 10us +75 that's to guarantee that we're down + + align:start position:0% +75 that's to guarantee that we're down + + + align:start position:0% +75 that's to guarantee that we're down +15 DB or more in the stop + + align:start position:0% +15 DB or more in the stop + + + align:start position:0% +15 DB or more in the stop +band the way I've drawn it here I've + + align:start position:0% +band the way I've drawn it here I've + + + align:start position:0% +band the way I've drawn it here I've +implied that I will exactly meet the + + align:start position:0% +implied that I will exactly meet the + + + align:start position:0% +implied that I will exactly meet the +specifications at the pass band Edge and + + align:start position:0% +specifications at the pass band Edge and + + + align:start position:0% +specifications at the pass band Edge and +exactly meet the specifications at the + + align:start position:0% +exactly meet the specifications at the + + + align:start position:0% +exactly meet the specifications at the +stop band Edge you can imagine of course + + align:start position:0% +stop band Edge you can imagine of course + + + align:start position:0% +stop band Edge you can imagine of course +that if I did that and then converted to + + align:start position:0% +that if I did that and then converted to + + + align:start position:0% +that if I did that and then converted to +a digital filter using impulse and + + align:start position:0% +a digital filter using impulse and + + + align:start position:0% +a digital filter using impulse and +variance that there would be an effect + + align:start position:0% +variance that there would be an effect + + + align:start position:0% +variance that there would be an effect +due to aliasing which in fact would + + align:start position:0% +due to aliasing which in fact would + + + align:start position:0% +due to aliasing which in fact would +would result in my not meeting exactly + + align:start position:0% +would result in my not meeting exactly + + + align:start position:0% +would result in my not meeting exactly +the specifications at the stop band Edge + + align:start position:0% +the specifications at the stop band Edge + + + align:start position:0% +the specifications at the stop band Edge +and that's a point that we'll deal with + + align:start position:0% +and that's a point that we'll deal with + + + align:start position:0% +and that's a point that we'll deal with +in a few minutes + + align:start position:0% +in a few minutes + + + align:start position:0% +in a few minutes +all right well now we have our + + align:start position:0% +all right well now we have our + + + align:start position:0% +all right well now we have our +specifications let me incidentally point + + align:start position:0% +specifications let me incidentally point + + + align:start position:0% +specifications let me incidentally point +out that there's this parameter capital + + align:start position:0% +out that there's this parameter capital + + + align:start position:0% +out that there's this parameter capital +T that we're carrying + + align:start position:0% +T that we're carrying + + + align:start position:0% +T that we're carrying +around and as I'll justify partly on the + + align:start position:0% +around and as I'll justify partly on the + + + align:start position:0% +around and as I'll justify partly on the +basis of this example the parameter + + align:start position:0% +basis of this example the parameter + + + align:start position:0% +basis of this example the parameter +capital t is an irrelevant parameter + + align:start position:0% +capital t is an irrelevant parameter + + + align:start position:0% +capital t is an irrelevant parameter +it's a parameter that will disappear + + align:start position:0% +it's a parameter that will disappear + + + align:start position:0% +it's a parameter that will disappear +we'll carry it through with us for this + + align:start position:0% +we'll carry it through with us for this + + + align:start position:0% +we'll carry it through with us for this +one example but for other example + + align:start position:0% +one example but for other example + + + align:start position:0% +one example but for other example +examples and problems that you work + + align:start position:0% +examples and problems that you work + + + align:start position:0% +examples and problems that you work +through the study + + align:start position:0% +through the study + + + align:start position:0% +through the study +guide uh the you should have absorbed + + align:start position:0% +guide uh the you should have absorbed + + + align:start position:0% +guide uh the you should have absorbed +the fact that capital t is irrelevant + + align:start position:0% +the fact that capital t is irrelevant + + + align:start position:0% +the fact that capital t is irrelevant +and in fact capital T can be chosen + + align:start position:0% +and in fact capital T can be chosen + + + align:start position:0% +and in fact capital T can be chosen +equal to Unity but let's carry it + + align:start position:0% +equal to Unity but let's carry it + + + align:start position:0% +equal to Unity but let's carry it +through in this example and just see how + + align:start position:0% +through in this example and just see how + + + align:start position:0% +through in this example and just see how +it + + align:start position:0% +it + + + align:start position:0% +it +disappears all right well so we want the + + align:start position:0% +disappears all right well so we want the + + + align:start position:0% +disappears all right well so we want the +analog Butterworth + + align:start position:0% +analog Butterworth + + + align:start position:0% +analog Butterworth +filter meaning these + + align:start position:0% +filter meaning these + + + align:start position:0% +filter meaning these +specifications and we want it at Omega + + align:start position:0% +specifications and we want it at Omega + + + align:start position:0% +specifications and we want it at Omega +equal to zero to have a gain magnitude + + align:start position:0% +equal to zero to have a gain magnitude + + + align:start position:0% +equal to zero to have a gain magnitude +squared function to be t^2 so that the + + align:start position:0% +squared function to be t^2 so that the + + + align:start position:0% +squared function to be t^2 so that the +magnitude is T so here we have the form + + align:start position:0% +magnitude is T so here we have the form + + + align:start position:0% +magnitude is T so here we have the form +then of the analog Butterworth + + align:start position:0% +then of the analog Butterworth + + + align:start position:0% +then of the analog Butterworth +filter and in order to meet these + + align:start position:0% +filter and in order to meet these + + + align:start position:0% +filter and in order to meet these +specifications at this frequency and + + align:start position:0% +specifications at this frequency and + + + align:start position:0% +specifications at this frequency and +this + + align:start position:0% +this + + + align:start position:0% +this +one we then have two + + align:start position:0% +one we then have two + + + align:start position:0% +one we then have two +equations one equation says that at + + align:start position:0% +equations one equation says that at + + + align:start position:0% +equations one equation says that at +Capital Omega equal to 2 pi over capital + + align:start position:0% +Capital Omega equal to 2 pi over capital + + + align:start position:0% +Capital Omega equal to 2 pi over capital +T we would like the + + align:start position:0% +T we would like the + + + align:start position:0% +T we would like the +value of the magnitude squared well the + + align:start position:0% +value of the magnitude squared well the + + + align:start position:0% +value of the magnitude squared well the +magnitude function to be T * 10us + + align:start position:0% +magnitude function to be T * 10us + + + align:start position:0% +magnitude function to be T * 10us +05 which implies that this denominator + + align:start position:0% +05 which implies that this denominator + + + align:start position:0% +05 which implies that this denominator +should be equal to + + align:start position:0% + + + + align:start position:0% + +10.1 second of all at the stop Bend + + align:start position:0% +10.1 second of all at the stop Bend + + + align:start position:0% +10.1 second of all at the stop Bend +frequency 3 Pi / capital + + align:start position:0% +frequency 3 Pi / capital + + + align:start position:0% +frequency 3 Pi / capital +T the fact that we want that to be the + + align:start position:0% +T the fact that we want that to be the + + + align:start position:0% +T the fact that we want that to be the +magnitude to be T * 10 + + align:start position:0% +magnitude to be T * 10 + + + align:start position:0% +magnitude to be T * 10 +-75 implies the magnitude squared is of + + align:start position:0% +-75 implies the magnitude squared is of + + + align:start position:0% +-75 implies the magnitude squared is of +course the square of that and we want + + align:start position:0% +course the square of that and we want + + + align:start position:0% +course the square of that and we want +then the denominator to be equal to 10^ + + align:start position:0% +then the denominator to be equal to 10^ + + + align:start position:0% +then the denominator to be equal to 10^ +the + + align:start position:0% +the + + + align:start position:0% +the +1.5 so we have two points that we're + + align:start position:0% +1.5 so we have two points that we're + + + align:start position:0% +1.5 so we have two points that we're +trying to nail down we have two + + align:start position:0% +trying to nail down we have two + + + align:start position:0% +trying to nail down we have two +parameters Omega Sub C and + + align:start position:0% +parameters Omega Sub C and + + + align:start position:0% +parameters Omega Sub C and +N from these two points that we're + + align:start position:0% +N from these two points that we're + + + align:start position:0% +N from these two points that we're +trying to nail down we get two + + align:start position:0% +trying to nail down we get two + + + align:start position:0% +trying to nail down we get two +equations and we can now solve these + + align:start position:0% +equations and we can now solve these + + + align:start position:0% +equations and we can now solve these +equations for our parameters Omega Sub C + + align:start position:0% +equations for our parameters Omega Sub C + + + align:start position:0% +equations for our parameters Omega Sub C +and capital + + align:start position:0% +and capital + + + align:start position:0% +and capital +N well if we do that and it's a little + + align:start position:0% +N well if we do that and it's a little + + + align:start position:0% +N well if we do that and it's a little +tedious to do it let me point out + + align:start position:0% +tedious to do it let me point out + + + align:start position:0% +tedious to do it let me point out +incidentally since we're trying to keep + + align:start position:0% +incidentally since we're trying to keep + + + align:start position:0% +incidentally since we're trying to keep +track of this capital T that capital T + + align:start position:0% +track of this capital T that capital T + + + align:start position:0% +track of this capital T that capital T +drops down into the numerator and so in + + align:start position:0% +drops down into the numerator and so in + + + align:start position:0% +drops down into the numerator and so in +fact we can solve for capital n and + + align:start position:0% +fact we can solve for capital n and + + + align:start position:0% +fact we can solve for capital n and +Omega Sub C time capital T in other + + align:start position:0% +Omega Sub C time capital T in other + + + align:start position:0% +Omega Sub C time capital T in other +words we can just move this down here + + align:start position:0% +words we can just move this down here + + + align:start position:0% +words we can just move this down here +algebraically and so we have then + + align:start position:0% +algebraically and so we have then + + + align:start position:0% +algebraically and so we have then +instead of the parameter Omega Sub C we + + align:start position:0% +instead of the parameter Omega Sub C we + + + align:start position:0% +instead of the parameter Omega Sub C we +have the parameter Omega Sub C * capital + + align:start position:0% +have the parameter Omega Sub C * capital + + + align:start position:0% +have the parameter Omega Sub C * capital +T all right if you grind through these + + align:start position:0% +T all right if you grind through these + + + align:start position:0% +T all right if you grind through these +two equations what results is a value + + align:start position:0% +two equations what results is a value + + + align:start position:0% +two equations what results is a value +for n equal to 5. 8858 and probably some + + align:start position:0% +for n equal to 5. 8858 and probably some + + + align:start position:0% +for n equal to 5. 8858 and probably some +other digits and Omega Sub C capital t + + align:start position:0% +other digits and Omega Sub C capital t + + + align:start position:0% +other digits and Omega Sub C capital t +equal to + + align:start position:0% +equal to + + + align:start position:0% +equal to +7474 and we could imagine that at this + + align:start position:0% +7474 and we could imagine that at this + + + align:start position:0% +7474 and we could imagine that at this +point we're done except + + align:start position:0% +point we're done except + + + align:start position:0% +point we're done except +that the parameter + + align:start position:0% +that the parameter + + + align:start position:0% +that the parameter +n corresponding to the order of the + + align:start position:0% +n corresponding to the order of the + + + align:start position:0% +n corresponding to the order of the +filter of course has to be an + + align:start position:0% +filter of course has to be an + + + align:start position:0% +filter of course has to be an +integer so what that means is that we + + align:start position:0% +integer so what that means is that we + + + align:start position:0% +integer so what that means is that we +can't use a value of n as I've indicated + + align:start position:0% +can't use a value of n as I've indicated + + + align:start position:0% +can't use a value of n as I've indicated +here we need an integer + + align:start position:0% +here we need an integer + + + align:start position:0% +here we need an integer +value also if we were to round this down + + align:start position:0% +value also if we were to round this down + + + align:start position:0% +value also if we were to round this down +or truncate it down to a choice of n + + align:start position:0% +or truncate it down to a choice of n + + + align:start position:0% +or truncate it down to a choice of n +equal to + + align:start position:0% +equal to + + + align:start position:0% +equal to +5 then since the order is lower you can + + align:start position:0% +5 then since the order is lower you can + + + align:start position:0% +5 then since the order is lower you can +imagine that the filter characteristics + + align:start position:0% +imagine that the filter characteristics + + + align:start position:0% +imagine that the filter characteristics +won't be as good in other words we're + + align:start position:0% +won't be as good in other words we're + + + align:start position:0% +won't be as good in other words we're +not going to meet these + + align:start position:0% +not going to meet these + + + align:start position:0% +not going to meet these +specifications so the other choice then + + align:start position:0% +specifications so the other choice then + + + align:start position:0% +specifications so the other choice then +is to use instead of this value of n use + + align:start position:0% +is to use instead of this value of n use + + + align:start position:0% +is to use instead of this value of n use +a value of n equal to six in other words + + align:start position:0% +a value of n equal to six in other words + + + align:start position:0% +a value of n equal to six in other words +round up to the highest to the next + + align:start position:0% +round up to the highest to the next + + + align:start position:0% +round up to the highest to the next +integer value and if we do that then + + align:start position:0% +integer value and if we do that then + + + align:start position:0% +integer value and if we do that then +these two equations will no longer be + + align:start position:0% +these two equations will no longer be + + + align:start position:0% +these two equations will no longer be +satisfed + + align:start position:0% +satisfed + + + align:start position:0% +satisfed +F we're now using a higher order filter + + align:start position:0% +F we're now using a higher order filter + + + align:start position:0% +F we're now using a higher order filter +than these equations would + + align:start position:0% +than these equations would + + + align:start position:0% +than these equations would +dictate of course we're using an integer + + align:start position:0% +dictate of course we're using an integer + + + align:start position:0% +dictate of course we're using an integer +order because that's what we need we're + + align:start position:0% +order because that's what we need we're + + + align:start position:0% +order because that's what we need we're +using a third order filter uh I'm sorry + + align:start position:0% +using a third order filter uh I'm sorry + + + align:start position:0% +using a third order filter uh I'm sorry +a sixth order + + align:start position:0% +a sixth order + + + align:start position:0% +a sixth order +filter and what that means is that if we + + align:start position:0% +filter and what that means is that if we + + + align:start position:0% +filter and what that means is that if we +choose n equal to + + align:start position:0% +choose n equal to + + + align:start position:0% +choose n equal to +6 we can satisfy this + + align:start position:0% +6 we can satisfy this + + + align:start position:0% +6 we can satisfy this +equation or we can satisfy this equation + + align:start position:0% +equation or we can satisfy this equation + + + align:start position:0% +equation or we can satisfy this equation +but we can't satisfy both of them + + align:start position:0% + + + + align:start position:0% + +well which one should we try to meet and + + align:start position:0% +well which one should we try to meet and + + + align:start position:0% +well which one should we try to meet and +which one should we + + align:start position:0% +which one should we + + + align:start position:0% +which one should we +exceed well we know that with impulse + + align:start position:0% +exceed well we know that with impulse + + + align:start position:0% +exceed well we know that with impulse +and variance there is the issue of + + align:start position:0% +and variance there is the issue of + + + align:start position:0% +and variance there is the issue of +aliasing and so in fact in impulse and + + align:start position:0% +aliasing and so in fact in impulse and + + + align:start position:0% +aliasing and so in fact in impulse and +variant design it will often happen that + + align:start position:0% +variant design it will often happen that + + + align:start position:0% +variant design it will often happen that +although we design exactly to meet the + + align:start position:0% +although we design exactly to meet the + + + align:start position:0% +although we design exactly to meet the +Stop and + + align:start position:0% +Stop and + + + align:start position:0% +Stop and +specifications the Stop and + + align:start position:0% +specifications the Stop and + + + align:start position:0% +specifications the Stop and +specifications won't be met because of + + align:start position:0% +specifications won't be met because of + + + align:start position:0% +specifications won't be met because of +iing consequently given the flexibility + + align:start position:0% +iing consequently given the flexibility + + + align:start position:0% +iing consequently given the flexibility +that we have due to the fact that we can + + align:start position:0% +that we have due to the fact that we can + + + align:start position:0% +that we have due to the fact that we can +actually Implement a higher order filter + + align:start position:0% +actually Implement a higher order filter + + + align:start position:0% +actually Implement a higher order filter +than these equations + + align:start position:0% +than these equations + + + align:start position:0% +than these equations +dictate to compensate for aliasing we + + align:start position:0% +dictate to compensate for aliasing we + + + align:start position:0% +dictate to compensate for aliasing we +can exceed the stop band specifications + + align:start position:0% +can exceed the stop band specifications + + + align:start position:0% +can exceed the stop band specifications +and meet exactly the pass band + + align:start position:0% +and meet exactly the pass band + + + align:start position:0% +and meet exactly the pass band +specifications so if we substitute for n + + align:start position:0% +specifications so if we substitute for n + + + align:start position:0% +specifications so if we substitute for n +Nal 6 into this equation + + align:start position:0% + + + + align:start position:0% + +that then requires that Omega sub CT be + + align:start position:0% +that then requires that Omega sub CT be + + + align:start position:0% +that then requires that Omega sub CT be +such that we exactly meet the pass band + + align:start position:0% +such that we exactly meet the pass band + + + align:start position:0% +such that we exactly meet the pass band +specifications in which case this + + align:start position:0% +specifications in which case this + + + align:start position:0% +specifications in which case this +equation won't be met in fact what will + + align:start position:0% +equation won't be met in fact what will + + + align:start position:0% +equation won't be met in fact what will +happen at the stopend edge is that the + + align:start position:0% +happen at the stopend edge is that the + + + align:start position:0% +happen at the stopend edge is that the +stopend specifications will be + + align:start position:0% +stopend specifications will be + + + align:start position:0% +stopend specifications will be +exceeded if we do this then we have for + + align:start position:0% +exceeded if we do this then we have for + + + align:start position:0% +exceeded if we do this then we have for +the equation that we solve for Omega sub + + align:start position:0% +the equation that we solve for Omega sub + + + align:start position:0% +the equation that we solve for Omega sub +CT from the equation which specified The + + align:start position:0% +CT from the equation which specified The + + + align:start position:0% +CT from the equation which specified The +passband Edge which is where we're going + + align:start position:0% +passband Edge which is where we're going + + + align:start position:0% +passband Edge which is where we're going +to meet the specs and what results then + + align:start position:0% +to meet the specs and what results then + + + align:start position:0% +to meet the specs and what results then +is for Omega sub + + align:start position:0% +is for Omega sub + + + align:start position:0% +is for Omega sub +CT this value rather than the previous + + align:start position:0% +CT this value rather than the previous + + + align:start position:0% +CT this value rather than the previous +value that had been obtained from the + + align:start position:0% +value that had been obtained from the + + + align:start position:0% +value that had been obtained from the +two + + align:start position:0% +two + + + align:start position:0% +two +equations well from these parameters + + align:start position:0% +equations well from these parameters + + + align:start position:0% +equations well from these parameters +then we can we have that Omega subc is + + align:start position:0% +then we can we have that Omega subc is + + + align:start position:0% +then we can we have that Omega subc is +7032 by capital T we can substitute + + align:start position:0% +7032 by capital T we can substitute + + + align:start position:0% +7032 by capital T we can substitute +these + + align:start position:0% +these + + + align:start position:0% +these +parameters into the form for the squared + + align:start position:0% +parameters into the form for the squared + + + align:start position:0% +parameters into the form for the squared +magnitude function H sub a of s * H sub + + align:start position:0% +magnitude function H sub a of s * H sub + + + align:start position:0% +magnitude function H sub a of s * H sub +a of minus s and actually it's this + + align:start position:0% +a of minus s and actually it's this + + + align:start position:0% +a of minus s and actually it's this +raised to the 2N which is the 2 * 6th + + align:start position:0% +raised to the 2N which is the 2 * 6th + + + align:start position:0% +raised to the 2N which is the 2 * 6th +power which is the 12th power so this + + align:start position:0% +power which is the 12th power so this + + + align:start position:0% +power which is the 12th power so this +then is the form for the analog squared + + align:start position:0% +then is the form for the analog squared + + + align:start position:0% +then is the form for the analog squared +magnitude + + align:start position:0% +magnitude + + + align:start position:0% +magnitude +function now notice that the parameter + + align:start position:0% +function now notice that the parameter + + + align:start position:0% +function now notice that the parameter +capital T still hasn't disappeared we + + align:start position:0% +capital T still hasn't disappeared we + + + align:start position:0% +capital T still hasn't disappeared we +still have it we have it there and we + + align:start position:0% +still have it we have it there and we + + + align:start position:0% +still have it we have it there and we +have it here but notice that when we + + align:start position:0% +have it here but notice that when we + + + align:start position:0% +have it here but notice that when we +substitute in for Omega Sub C this + + align:start position:0% +substitute in for Omega Sub C this + + + align:start position:0% +substitute in for Omega Sub C this +number divided by capital T if you track + + align:start position:0% +number divided by capital T if you track + + + align:start position:0% +number divided by capital T if you track +through that + + align:start position:0% +through that + + + align:start position:0% +through that +algebra capital T reappears in this + + align:start position:0% +algebra capital T reappears in this + + + align:start position:0% +algebra capital T reappears in this +expression at as a multiplier on S that + + align:start position:0% +expression at as a multiplier on S that + + + align:start position:0% +expression at as a multiplier on S that +is we had 7032 divided by capital T that + + align:start position:0% +is we had 7032 divided by capital T that + + + align:start position:0% +is we had 7032 divided by capital T that +gets reflected back up into this + + align:start position:0% +gets reflected back up into this + + + align:start position:0% +gets reflected back up into this +numerator so that we have S * cap + + align:start position:0% +numerator so that we have S * cap + + + align:start position:0% +numerator so that we have S * cap +capital T well let's see what that + + align:start position:0% +capital T well let's see what that + + + align:start position:0% +capital T well let's see what that +means suppose that capital T were equal + + align:start position:0% +means suppose that capital T were equal + + + align:start position:0% +means suppose that capital T were equal +to + + align:start position:0% +to + + + align:start position:0% +to +one and we got an analog impulse + + align:start position:0% +one and we got an analog impulse + + + align:start position:0% +one and we got an analog impulse +response H Suba of + + align:start position:0% +response H Suba of + + + align:start position:0% +response H Suba of +t or the system function H sub B of + + align:start position:0% +t or the system function H sub B of + + + align:start position:0% +t or the system function H sub B of +s If + + align:start position:0% +s If + + + align:start position:0% +s If +instead we reinserted capital T and + + align:start position:0% +instead we reinserted capital T and + + + align:start position:0% +instead we reinserted capital T and +considered H Suba of s * capital + + align:start position:0% +considered H Suba of s * capital + + + align:start position:0% +considered H Suba of s * capital +T multip IED by capital + + align:start position:0% +T multip IED by capital + + + align:start position:0% +T multip IED by capital +T that impulse response would be related + + align:start position:0% +T that impulse response would be related + + + align:start position:0% +T that impulse response would be related +to this one by simply a Time scaling + + align:start position:0% +to this one by simply a Time scaling + + + align:start position:0% +to this one by simply a Time scaling +that in other words this one would be + + align:start position:0% +that in other words this one would be + + + align:start position:0% +that in other words this one would be +replaced by H Suba of T divided capital + + align:start position:0% +replaced by H Suba of T divided capital + + + align:start position:0% +replaced by H Suba of T divided capital +T well let's look at this and ask what + + align:start position:0% +T well let's look at this and ask what + + + align:start position:0% +T well let's look at this and ask what +happens when we sample it at samples + + align:start position:0% +happens when we sample it at samples + + + align:start position:0% +happens when we sample it at samples +spaced by capital T so we we look at + + align:start position:0% +spaced by capital T so we we look at + + + align:start position:0% +spaced by capital T so we we look at +this impulse response with t replaced by + + align:start position:0% +this impulse response with t replaced by + + + align:start position:0% +this impulse response with t replaced by +n * capital + + align:start position:0% +n * capital + + + align:start position:0% +n * capital +T as we've specified here and we observe + + align:start position:0% +T as we've specified here and we observe + + + align:start position:0% +T as we've specified here and we observe +that no matter what we pick capital T to + + align:start position:0% +that no matter what we pick capital T to + + + align:start position:0% +that no matter what we pick capital T to +be that parameter disappears because + + align:start position:0% +be that parameter disappears because + + + align:start position:0% +be that parameter disappears because +little t equal to n * capital T gives us + + align:start position:0% +little t equal to n * capital T gives us + + + align:start position:0% +little t equal to n * capital T gives us +samples H sub a of n which are exactly + + align:start position:0% +samples H sub a of n which are exactly + + + align:start position:0% +samples H sub a of n which are exactly +the same samples that we would get no + + align:start position:0% +the same samples that we would get no + + + align:start position:0% +the same samples that we would get no +matter how we chose the parameter + + align:start position:0% +matter how we chose the parameter + + + align:start position:0% +matter how we chose the parameter +capital T or equivalently whether or not + + align:start position:0% +capital T or equivalently whether or not + + + align:start position:0% +capital T or equivalently whether or not +we chose the parameter capital t equal + + align:start position:0% +we chose the parameter capital t equal + + + align:start position:0% +we chose the parameter capital t equal +to Unity + + align:start position:0% + + + + align:start position:0% + +I think that it requires a little + + align:start position:0% +I think that it requires a little + + + align:start position:0% +I think that it requires a little +reflection to absorb this point it's + + align:start position:0% +reflection to absorb this point it's + + + align:start position:0% +reflection to absorb this point it's +basically tied to the fact that the + + align:start position:0% +basically tied to the fact that the + + + align:start position:0% +basically tied to the fact that the +frequency + + align:start position:0% +frequency + + + align:start position:0% +frequency +response is specified for the digital + + align:start position:0% +response is specified for the digital + + + align:start position:0% +response is specified for the digital +filter not for the analog filter and + + align:start position:0% +filter not for the analog filter and + + + align:start position:0% +filter not for the analog filter and +specifying the frequency response for + + align:start position:0% +specifying the frequency response for + + + align:start position:0% +specifying the frequency response for +the digital filter in effect specifies + + align:start position:0% +the digital filter in effect specifies + + + align:start position:0% +the digital filter in effect specifies +Omega times Capital Omega time capital T + + align:start position:0% +Omega times Capital Omega time capital T + + + align:start position:0% +Omega times Capital Omega time capital T +well I leave it to you to uh think about + + align:start position:0% +well I leave it to you to uh think about + + + align:start position:0% +well I leave it to you to uh think about +this a little but the important point is + + align:start position:0% +this a little but the important point is + + + align:start position:0% +this a little but the important point is +that in fact this parameter T if we + + align:start position:0% +that in fact this parameter T if we + + + align:start position:0% +that in fact this parameter T if we +specify the + + align:start position:0% +specify the + + + align:start position:0% +specify the +filter in terms of digital + + align:start position:0% +filter in terms of digital + + + align:start position:0% +filter in terms of digital +specifications this parameter capital t + + align:start position:0% +specifications this parameter capital t + + + align:start position:0% +specifications this parameter capital t +is really + + align:start position:0% + + + + align:start position:0% + +irrelevant all right well so here is our + + align:start position:0% +irrelevant all right well so here is our + + + align:start position:0% +irrelevant all right well so here is our +analog + + align:start position:0% +analog + + + align:start position:0% +analog +design and + + align:start position:0% +design and + + + align:start position:0% +design and +we can obtain H Suba of s from this + + align:start position:0% +we can obtain H Suba of s from this + + + align:start position:0% +we can obtain H Suba of s from this +according to the method that we talked + + align:start position:0% +according to the method that we talked + + + align:start position:0% +according to the method that we talked +about previously taking the left half + + align:start position:0% +about previously taking the left half + + + align:start position:0% +about previously taking the left half +plane poles of this expression + + align:start position:0% +plane poles of this expression + + + align:start position:0% +plane poles of this expression +converting those to a digital filter by + + align:start position:0% +converting those to a digital filter by + + + align:start position:0% +converting those to a digital filter by +using the transformation that we + + align:start position:0% +using the transformation that we + + + align:start position:0% +using the transformation that we +discussed in the previous two lectures + + align:start position:0% +discussed in the previous two lectures + + + align:start position:0% +discussed in the previous two lectures +expanding for example in terms of residu + + align:start position:0% +expanding for example in terms of residu + + + align:start position:0% +expanding for example in terms of residu +and poles and then applying the impulse + + align:start position:0% +and poles and then applying the impulse + + + align:start position:0% +and poles and then applying the impulse +and variant + + align:start position:0% +and variant + + + align:start position:0% +and variant +transformation and if we do that what + + align:start position:0% +transformation and if we do that what + + + align:start position:0% +transformation and if we do that what +what results is an analog uh I'm sorry a + + align:start position:0% +what results is an analog uh I'm sorry a + + + align:start position:0% +what results is an analog uh I'm sorry a +digital low pass filter which was the + + align:start position:0% +digital low pass filter which was the + + + align:start position:0% +digital low pass filter which was the +low pass filter that we set out to + + align:start position:0% +low pass filter that we set out to + + + align:start position:0% +low pass filter that we set out to +design and let me just show how those + + align:start position:0% +design and let me just show how those + + + align:start position:0% +design and let me just show how those +specifications or how that design comes + + align:start position:0% +specifications or how that design comes + + + align:start position:0% +specifications or how that design comes +out so this for the example that we've + + align:start position:0% +out so this for the example that we've + + + align:start position:0% +out so this for the example that we've +been talking about is a graph of the + + align:start position:0% +been talking about is a graph of the + + + align:start position:0% +been talking about is a graph of the +frequency response + + align:start position:0% +frequency response + + + align:start position:0% +frequency response +characteristics here is the magnitude as + + align:start position:0% +characteristics here is the magnitude as + + + align:start position:0% +characteristics here is the magnitude as +a function of digital frequency + + align:start position:0% +a function of digital frequency + + + align:start position:0% +a function of digital frequency +Omega and here is the same frequency + + align:start position:0% +Omega and here is the same frequency + + + align:start position:0% +Omega and here is the same frequency +response plotted in terms of + + align:start position:0% +response plotted in terms of + + + align:start position:0% +response plotted in terms of +DB and we see that we had a in the + + align:start position:0% +DB and we see that we had a in the + + + align:start position:0% +DB and we see that we had a in the +specifications a pass band Edge at 0 2 + + align:start position:0% +specifications a pass band Edge at 0 2 + + + align:start position:0% +specifications a pass band Edge at 0 2 +pi a stop band Edge at 3 + + align:start position:0% +pi a stop band Edge at 3 + + + align:start position:0% +pi a stop band Edge at 3 +Pi at0 2 pi we asked that the gain be + + align:start position:0% +Pi at0 2 pi we asked that the gain be + + + align:start position:0% +Pi at0 2 pi we asked that the gain be +down by + + align:start position:0% +down by + + + align:start position:0% +down by +1db and uh of course it's hard to tell + + align:start position:0% +1db and uh of course it's hard to tell + + + align:start position:0% +1db and uh of course it's hard to tell +exactly that we're down 1db but in fact + + align:start position:0% +exactly that we're down 1db but in fact + + + align:start position:0% +exactly that we're down 1db but in fact +we are and at Omega equal to 3 Pi our + + align:start position:0% +we are and at Omega equal to 3 Pi our + + + align:start position:0% +we are and at Omega equal to 3 Pi our +specification was that we wanted to be + + align:start position:0% +specification was that we wanted to be + + + align:start position:0% +specification was that we wanted to be +down by 15 + + align:start position:0% +down by 15 + + + align:start position:0% +down by 15 +DB in fact we + + align:start position:0% +DB in fact we + + + align:start position:0% +DB in fact we +overcompensated because of the fact that + + align:start position:0% +overcompensated because of the fact that + + + align:start position:0% +overcompensated because of the fact that +we had to round the order of the filter + + align:start position:0% +we had to round the order of the filter + + + align:start position:0% +we had to round the order of the filter +up to an integer value and you can see + + align:start position:0% +up to an integer value and you can see + + + align:start position:0% +up to an integer value and you can see +in fact that if you look at this + + align:start position:0% +in fact that if you look at this + + + align:start position:0% +in fact that if you look at this +carefully we exceed the specifications + + align:start position:0% +carefully we exceed the specifications + + + align:start position:0% +carefully we exceed the specifications +at 3 Pi by a little bit in other words + + align:start position:0% +at 3 Pi by a little bit in other words + + + align:start position:0% +at 3 Pi by a little bit in other words +we're down by a little more than 15 DB + + align:start position:0% +we're down by a little more than 15 DB + + + align:start position:0% +we're down by a little more than 15 DB +in fact for this particular filter you + + align:start position:0% +in fact for this particular filter you + + + align:start position:0% +in fact for this particular filter you +can imagine that the effect of aliasing + + align:start position:0% +can imagine that the effect of aliasing + + + align:start position:0% +can imagine that the effect of aliasing +is in fact rather minimal because this + + align:start position:0% +is in fact rather minimal because this + + + align:start position:0% +is in fact rather minimal because this +frequency response by the time we get + + align:start position:0% +frequency response by the time we get + + + align:start position:0% +frequency response by the time we get +out to Pi is essentially zero here we're + + align:start position:0% +out to Pi is essentially zero here we're + + + align:start position:0% +out to Pi is essentially zero here we're +down to uh- 75 DB and that's of course + + align:start position:0% +down to uh- 75 DB and that's of course + + + align:start position:0% +down to uh- 75 DB and that's of course +the amount that would get alias back in + + align:start position:0% +the amount that would get alias back in + + + align:start position:0% +the amount that would get alias back in +so this is the resulting filter + + align:start position:0% +so this is the resulting filter + + + align:start position:0% +so this is the resulting filter +frequency characteristics for the + + align:start position:0% +frequency characteristics for the + + + align:start position:0% +frequency characteristics for the +impulse andari design where we exceed + + align:start position:0% +impulse andari design where we exceed + + + align:start position:0% +impulse andari design where we exceed +slightly the stop andand Edge + + align:start position:0% +slightly the stop andand Edge + + + align:start position:0% +slightly the stop andand Edge +specifications now the next thing that + + align:start position:0% +specifications now the next thing that + + + align:start position:0% +specifications now the next thing that +I'd like to go on to is the a the + + align:start position:0% +I'd like to go on to is the a the + + + align:start position:0% +I'd like to go on to is the a the +corresponding design the design of the + + align:start position:0% +corresponding design the design of the + + + align:start position:0% +corresponding design the design of the +corresponding Butterworth filter Now + + align:start position:0% +corresponding Butterworth filter Now + + + align:start position:0% +corresponding Butterworth filter Now +using the bilinear transformation rather + + align:start position:0% +using the bilinear transformation rather + + + align:start position:0% +using the bilinear transformation rather +than using impulse and + + align:start position:0% +than using impulse and + + + align:start position:0% +than using impulse and +variance I remind you that the basic + + align:start position:0% +variance I remind you that the basic + + + align:start position:0% +variance I remind you that the basic +idea + + align:start position:0% +idea + + + align:start position:0% +idea +with the bilinear transformation as + + align:start position:0% +with the bilinear transformation as + + + align:start position:0% +with the bilinear transformation as +we've discussed in the last + + align:start position:0% +we've discussed in the last + + + align:start position:0% +we've discussed in the last +lectures is that we + + align:start position:0% +lectures is that we + + + align:start position:0% +lectures is that we +basically choose the digital the I'm + + align:start position:0% +basically choose the digital the I'm + + + align:start position:0% +basically choose the digital the I'm +sorry the + + align:start position:0% +sorry the + + + align:start position:0% +sorry the +analog + + align:start position:0% +analog + + + align:start position:0% +analog +specifications by pre-ww warping the + + align:start position:0% +specifications by pre-ww warping the + + + align:start position:0% +specifications by pre-ww warping the +critical frequencies for the digital + + align:start position:0% +critical frequencies for the digital + + + align:start position:0% +critical frequencies for the digital +filter through the nonlinear Distortion + + align:start position:0% +filter through the nonlinear Distortion + + + align:start position:0% +filter through the nonlinear Distortion +curve corresponding to the bilinear + + align:start position:0% +curve corresponding to the bilinear + + + align:start position:0% +curve corresponding to the bilinear +transformation + + align:start position:0% +transformation + + + align:start position:0% +transformation +so we would start here for the digital + + align:start position:0% +so we would start here for the digital + + + align:start position:0% +so we would start here for the digital +filter uh of course here we're talking + + align:start position:0% +filter uh of course here we're talking + + + align:start position:0% +filter uh of course here we're talking +about a monotonic filter rather than one + + align:start position:0% +about a monotonic filter rather than one + + + align:start position:0% +about a monotonic filter rather than one +that ripples but we have a pass band + + align:start position:0% +that ripples but we have a pass band + + + align:start position:0% +that ripples but we have a pass band +Edge at0 2 pi a stop band Edge at 3 Pi + + align:start position:0% +Edge at0 2 pi a stop band Edge at 3 Pi + + + align:start position:0% +Edge at0 2 pi a stop band Edge at 3 Pi +we reflect those critical frequencies + + align:start position:0% +we reflect those critical frequencies + + + align:start position:0% +we reflect those critical frequencies +through the arc tangent curve to obtain + + align:start position:0% +through the arc tangent curve to obtain + + + align:start position:0% +through the arc tangent curve to obtain +the corresponding critical frequencies + + align:start position:0% +the corresponding critical frequencies + + + align:start position:0% +the corresponding critical frequencies +for the analog Butterworth filter when + + align:start position:0% +for the analog Butterworth filter when + + + align:start position:0% +for the analog Butterworth filter when +the analog Butterworth filter is + + align:start position:0% +the analog Butterworth filter is + + + align:start position:0% +the analog Butterworth filter is +designed we then obtain the digital + + align:start position:0% +designed we then obtain the digital + + + align:start position:0% +designed we then obtain the digital +Butterworth filter by transforming this + + align:start position:0% +Butterworth filter by transforming this + + + align:start position:0% +Butterworth filter by transforming this +filter back through the bilinear + + align:start position:0% +filter back through the bilinear + + + align:start position:0% +filter back through the bilinear +transformation so let's look at how this + + align:start position:0% +transformation so let's look at how this + + + align:start position:0% +transformation so let's look at how this +design works then we have as we've just + + align:start position:0% +design works then we have as we've just + + + align:start position:0% +design works then we have as we've just +shown reflected on that curve we begin + + align:start position:0% +shown reflected on that curve we begin + + + align:start position:0% +shown reflected on that curve we begin +with the digital frequency specification + + align:start position:0% +with the digital frequency specification + + + align:start position:0% +with the digital frequency specification +reflect those through the bilinear + + align:start position:0% +reflect those through the bilinear + + + align:start position:0% +reflect those through the bilinear +warping curve to the analog + + align:start position:0% +warping curve to the analog + + + align:start position:0% +warping curve to the analog +specifications and consequently the + + align:start position:0% +specifications and consequently the + + + align:start position:0% +specifications and consequently the +critical + + align:start position:0% +critical + + + align:start position:0% +critical +frequencies and let me emphasize first + + align:start position:0% +frequencies and let me emphasize first + + + align:start position:0% +frequencies and let me emphasize first +of all that just as with impulse and + + align:start position:0% +of all that just as with impulse and + + + align:start position:0% +of all that just as with impulse and +variance you can show that the parameter + + align:start position:0% +variance you can show that the parameter + + + align:start position:0% +variance you can show that the parameter +capital t is an irrelevant parameter we + + align:start position:0% +capital t is an irrelevant parameter we + + + align:start position:0% +capital t is an irrelevant parameter we +could in fact carry it all the way + + align:start position:0% +could in fact carry it all the way + + + align:start position:0% +could in fact carry it all the way +through and what would happen is that we + + align:start position:0% +through and what would happen is that we + + + align:start position:0% +through and what would happen is that we +can we would would find that no matter + + align:start position:0% +can we would would find that no matter + + + align:start position:0% +can we would would find that no matter +what we chose capital T to be the + + align:start position:0% +what we chose capital T to be the + + + align:start position:0% +what we chose capital T to be the +digital filter design that resulted + + align:start position:0% +digital filter design that resulted + + + align:start position:0% +digital filter design that resulted +would be exactly the same so in fact for + + align:start position:0% +would be exactly the same so in fact for + + + align:start position:0% +would be exactly the same so in fact for +this example I'll work through it simply + + align:start position:0% +this example I'll work through it simply + + + align:start position:0% +this example I'll work through it simply +with capital t equal to + + align:start position:0% +with capital t equal to + + + align:start position:0% +with capital t equal to +1 all right with capital t equal to one + + align:start position:0% +1 all right with capital t equal to one + + + align:start position:0% +1 all right with capital t equal to one +we reflect these critical frequencies + + align:start position:0% +we reflect these critical frequencies + + + align:start position:0% +we reflect these critical frequencies +into this pass band frequency Edge and + + align:start position:0% +into this pass band frequency Edge and + + + align:start position:0% +into this pass band frequency Edge and +this stopend Edge and consequently the + + align:start position:0% +this stopend Edge and consequently the + + + align:start position:0% +this stopend Edge and consequently the +the analog filter this is the analog + + align:start position:0% +the analog filter this is the analog + + + align:start position:0% +the analog filter this is the analog +filter the analog filter that we design + + align:start position:0% +filter the analog filter that we design + + + align:start position:0% +filter the analog filter that we design +is one that meets these + + align:start position:0% +is one that meets these + + + align:start position:0% +is one that meets these +specifications and consequently we we + + align:start position:0% +specifications and consequently we we + + + align:start position:0% +specifications and consequently we we +have again the two equations that say + + align:start position:0% +have again the two equations that say + + + align:start position:0% +have again the two equations that say +that at the pass band + + align:start position:0% +that at the pass band + + + align:start position:0% +that at the pass band +Edge we want the magnitude to + + align:start position:0% +Edge we want the magnitude to + + + align:start position:0% +Edge we want the magnitude to +be within One DB of unity and at the + + align:start position:0% +be within One DB of unity and at the + + + align:start position:0% +be within One DB of unity and at the +stop band Edge we want the magnitude to + + align:start position:0% +stop band Edge we want the magnitude to + + + align:start position:0% +stop band Edge we want the magnitude to +be less than down down by more than 15 + + align:start position:0% +be less than down down by more than 15 + + + align:start position:0% +be less than down down by more than 15 +DB and the two equations that result are + + align:start position:0% +DB and the two equations that result are + + + align:start position:0% +DB and the two equations that result are +these exactly the same as we had in the + + align:start position:0% +these exactly the same as we had in the + + + align:start position:0% +these exactly the same as we had in the +impulse and variant case except that the + + align:start position:0% +impulse and variant case except that the + + + align:start position:0% +impulse and variant case except that the +frequencies are + + align:start position:0% +frequencies are + + + align:start position:0% +frequencies are +different so now substituting in for the + + align:start position:0% +different so now substituting in for the + + + align:start position:0% +different so now substituting in for the +form of the analog Butterworth filter + + align:start position:0% +form of the analog Butterworth filter + + + align:start position:0% +form of the analog Butterworth filter +into these + + align:start position:0% +into these + + + align:start position:0% +into these +expressions and setting this up for + + align:start position:0% +expressions and setting this up for + + + align:start position:0% +expressions and setting this up for +equality in these Expressions what + + align:start position:0% +equality in these Expressions what + + + align:start position:0% +equality in these Expressions what +results then are the two equations which + + align:start position:0% +results then are the two equations which + + + align:start position:0% +results then are the two equations which +are identical to the two equations that + + align:start position:0% +are identical to the two equations that + + + align:start position:0% +are identical to the two equations that +we had for the impulse and variant + + align:start position:0% +we had for the impulse and variant + + + align:start position:0% +we had for the impulse and variant +design except that the + + align:start position:0% +design except that the + + + align:start position:0% +design except that the +frequencies at which the pass band and + + align:start position:0% +frequencies at which the pass band and + + + align:start position:0% +frequencies at which the pass band and +stop band edges of the analog + + align:start position:0% +stop band edges of the analog + + + align:start position:0% +stop band edges of the analog +Butterworth filter fall are different + + align:start position:0% +Butterworth filter fall are different + + + align:start position:0% +Butterworth filter fall are different +they're different because of the warping + + align:start position:0% +they're different because of the warping + + + align:start position:0% +they're different because of the warping +of the bilinear curve or the pre warping + + align:start position:0% +of the bilinear curve or the pre warping + + + align:start position:0% +of the bilinear curve or the pre warping +that we have to apply so these are the + + align:start position:0% +that we have to apply so these are the + + + align:start position:0% +that we have to apply so these are the +two + + align:start position:0% +two + + + align:start position:0% +two +equations and the resulting if we solve + + align:start position:0% +equations and the resulting if we solve + + + align:start position:0% +equations and the resulting if we solve +these two equations for capital N the + + align:start position:0% +these two equations for capital N the + + + align:start position:0% +these two equations for capital N the +result the resulting value for capital N + + align:start position:0% +result the resulting value for capital N + + + align:start position:0% +result the resulting value for capital N +is 5.3 and some digits notice + + align:start position:0% +is 5.3 and some digits notice + + + align:start position:0% +is 5.3 and some digits notice +incidentally that it's less than it was + + align:start position:0% +incidentally that it's less than it was + + + align:start position:0% +incidentally that it's less than it was +for the impulse invariant design and in + + align:start position:0% +for the impulse invariant design and in + + + align:start position:0% +for the impulse invariant design and in +general that's a characteristic of the + + align:start position:0% +general that's a characteristic of the + + + align:start position:0% +general that's a characteristic of the +bilinear transformation but so it's less + + align:start position:0% +bilinear transformation but so it's less + + + align:start position:0% +bilinear transformation but so it's less +but it is non + + align:start position:0% +but it is non + + + align:start position:0% +but it is non +integer so the first thing we can ask + + align:start position:0% +integer so the first thing we can ask + + + align:start position:0% +integer so the first thing we can ask +again is could we just simply truncate + + align:start position:0% +again is could we just simply truncate + + + align:start position:0% +again is could we just simply truncate +this down or round it down to the + + align:start position:0% +this down or round it down to the + + + align:start position:0% +this down or round it down to the +nearest integer value in other words N + + align:start position:0% +nearest integer value in other words N + + + align:start position:0% +nearest integer value in other words N +equals 5 but of course if we did that + + align:start position:0% +equals 5 but of course if we did that + + + align:start position:0% +equals 5 but of course if we did that +then we wouldn't be able to pick Omega + + align:start position:0% +then we wouldn't be able to pick Omega + + + align:start position:0% +then we wouldn't be able to pick Omega +Sub C so that these equations were + + align:start position:0% +Sub C so that these equations were + + + align:start position:0% +Sub C so that these equations were +satisfied or so that the specifications + + align:start position:0% +satisfied or so that the specifications + + + align:start position:0% +satisfied or so that the specifications +were met or exceeded so in fact we need + + align:start position:0% +were met or exceeded so in fact we need + + + align:start position:0% +were met or exceeded so in fact we need +to choose we have to choose n equal to 6 + + align:start position:0% +to choose we have to choose n equal to 6 + + + align:start position:0% +to choose we have to choose n equal to 6 +we have to choose the next highest + + align:start position:0% +we have to choose the next highest + + + align:start position:0% +we have to choose the next highest +integer + + align:start position:0% +integer + + + align:start position:0% +integer +value choosing n equal to 6 we then have + + align:start position:0% +value choosing n equal to 6 we then have + + + align:start position:0% +value choosing n equal to 6 we then have +the choice of exactly satisfying this + + align:start position:0% +the choice of exactly satisfying this + + + align:start position:0% +the choice of exactly satisfying this +equation or exactly satisfying this + + align:start position:0% +equation or exactly satisfying this + + + align:start position:0% +equation or exactly satisfying this +equation or in fact not satisfying + + align:start position:0% +equation or in fact not satisfying + + + align:start position:0% +equation or in fact not satisfying +either one of them but playing back and + + align:start position:0% +either one of them but playing back and + + + align:start position:0% +either one of them but playing back and +forth between the + + align:start position:0% +forth between the + + + align:start position:0% +forth between the +two well let's do it in a particular way + + align:start position:0% +two well let's do it in a particular way + + + align:start position:0% +two well let's do it in a particular way +we can for + + align:start position:0% +we can for + + + align:start position:0% +we can for +example exactly meet the stop Bend + + align:start position:0% +example exactly meet the stop Bend + + + align:start position:0% +example exactly meet the stop Bend +specific ations in other words we can + + align:start position:0% +specific ations in other words we can + + + align:start position:0% +specific ations in other words we can +use Nal 6 in this equation and solve for + + align:start position:0% +use Nal 6 in this equation and solve for + + + align:start position:0% +use Nal 6 in this equation and solve for +Omega Sub C in which case the pass band + + align:start position:0% +Omega Sub C in which case the pass band + + + align:start position:0% +Omega Sub C in which case the pass band +specifications will be + + align:start position:0% +specifications will be + + + align:start position:0% +specifications will be +exceeded recall that in the impulse and + + align:start position:0% +exceeded recall that in the impulse and + + + align:start position:0% +exceeded recall that in the impulse and +variant design we did it the other way + + align:start position:0% +variant design we did it the other way + + + align:start position:0% +variant design we did it the other way +around we met exactly the pass band + + align:start position:0% +around we met exactly the pass band + + + align:start position:0% +around we met exactly the pass band +specifications in which case the stop + + align:start position:0% +specifications in which case the stop + + + align:start position:0% +specifications in which case the stop +Bend specs were exceeded but there we + + align:start position:0% +Bend specs were exceeded but there we + + + align:start position:0% +Bend specs were exceeded but there we +had a good reason for doing that the + + align:start position:0% +had a good reason for doing that the + + + align:start position:0% +had a good reason for doing that the +reason that we did that is because we + + align:start position:0% +reason that we did that is because we + + + align:start position:0% +reason that we did that is because we +knew in advance that in any case the p b + + align:start position:0% +knew in advance that in any case the p b + + + align:start position:0% +knew in advance that in any case the p b +specs wouldn't be met exactly because of + + align:start position:0% +specs wouldn't be met exactly because of + + + align:start position:0% +specs wouldn't be met exactly because of +the effect of aliasing for the bilinear + + align:start position:0% +the effect of aliasing for the bilinear + + + align:start position:0% +the effect of aliasing for the bilinear +transformation we don't have a problem + + align:start position:0% +transformation we don't have a problem + + + align:start position:0% +transformation we don't have a problem +with aliasing so in fact we're free to + + align:start position:0% +with aliasing so in fact we're free to + + + align:start position:0% +with aliasing so in fact we're free to +play with this flexibility in a more + + align:start position:0% +play with this flexibility in a more + + + align:start position:0% +play with this flexibility in a more +General way all right well in any case + + align:start position:0% +General way all right well in any case + + + align:start position:0% +General way all right well in any case +then if we meet the stop end specs + + align:start position:0% +then if we meet the stop end specs + + + align:start position:0% +then if we meet the stop end specs +substituting n equal 6 in this equation + + align:start position:0% +substituting n equal 6 in this equation + + + align:start position:0% +substituting n equal 6 in this equation +and solving for Omega Sub C we end up + + align:start position:0% +and solving for Omega Sub C we end up + + + align:start position:0% +and solving for Omega Sub C we end up +with a value for Omega subc which is 766 + + align:start position:0% +with a value for Omega subc which is 766 + + + align:start position:0% +with a value for Omega subc which is 766 + + align:start position:0% + + + align:start position:0% +two and so this then gives us the + + align:start position:0% +two and so this then gives us the + + + align:start position:0% +two and so this then gives us the +parameters Omega Sub C and N for the + + align:start position:0% +parameters Omega Sub C and N for the + + + align:start position:0% +parameters Omega Sub C and N for the +analog Butterworth + + align:start position:0% +analog Butterworth + + + align:start position:0% +analog Butterworth +filter we can then use those + + align:start position:0% +filter we can then use those + + + align:start position:0% +filter we can then use those +specifications again to generate the + + align:start position:0% +specifications again to generate the + + + align:start position:0% +specifications again to generate the +pole pattern for the squared magnitude + + align:start position:0% +pole pattern for the squared magnitude + + + align:start position:0% +pole pattern for the squared magnitude +function H sub a of stimes H sub a of + + align:start position:0% +function H sub a of stimes H sub a of + + + align:start position:0% +function H sub a of stimes H sub a of +minus + + align:start position:0% + + + + align:start position:0% + +s factor this by choosing the left half + + align:start position:0% +s factor this by choosing the left half + + + align:start position:0% +s factor this by choosing the left half +plane poles in the S plane and then + + align:start position:0% +plane poles in the S plane and then + + + align:start position:0% +plane poles in the S plane and then +mapping this function to a digital + + align:start position:0% +mapping this function to a digital + + + align:start position:0% +mapping this function to a digital +filter using the bilinear transformation + + align:start position:0% +filter using the bilinear transformation + + + align:start position:0% +filter using the bilinear transformation +and let's now look at how this filter + + align:start position:0% +and let's now look at how this filter + + + align:start position:0% +and let's now look at how this filter +comes out as compared with + + align:start position:0% +comes out as compared with + + + align:start position:0% +comes out as compared with +the digital filter that we obtained by + + align:start position:0% +the digital filter that we obtained by + + + align:start position:0% +the digital filter that we obtained by +digital Butterworth filter that we + + align:start position:0% +digital Butterworth filter that we + + + align:start position:0% +digital Butterworth filter that we +obtained by using impulse and + + align:start position:0% +obtained by using impulse and + + + align:start position:0% +obtained by using impulse and +variance well again I have a display of + + align:start position:0% +variance well again I have a display of + + + align:start position:0% +variance well again I have a display of +the mag magnitude of the frequency + + align:start position:0% +the mag magnitude of the frequency + + + align:start position:0% +the mag magnitude of the frequency +response and also the gain in + + align:start position:0% + + + + align:start position:0% + +DB from what you may recall from the + + align:start position:0% +DB from what you may recall from the + + + align:start position:0% +DB from what you may recall from the +curve that I showed + + align:start position:0% +curve that I showed + + + align:start position:0% +curve that I showed +previously this looks roughly the same + + align:start position:0% +previously this looks roughly the same + + + align:start position:0% +previously this looks roughly the same +it's it's a monotonic filter and drops + + align:start position:0% +it's it's a monotonic filter and drops + + + align:start position:0% +it's it's a monotonic filter and drops +off U it's down by some amount at 0 2 pi + + align:start position:0% +off U it's down by some amount at 0 2 pi + + + align:start position:0% +off U it's down by some amount at 0 2 pi +and the stop Bend is at 3 + + align:start position:0% +and the stop Bend is at 3 + + + align:start position:0% +and the stop Bend is at 3 +Pi in particular according to the + + align:start position:0% +Pi in particular according to the + + + align:start position:0% +Pi in particular according to the +specifications we wanted this to be down + + align:start position:0% +specifications we wanted this to be down + + + align:start position:0% +specifications we wanted this to be down +by no more than 1 DB at 0 2 pi well uh + + align:start position:0% +by no more than 1 DB at 0 2 pi well uh + + + align:start position:0% +by no more than 1 DB at 0 2 pi well uh +it's hard to again to see that this is 1 + + align:start position:0% +it's hard to again to see that this is 1 + + + align:start position:0% +it's hard to again to see that this is 1 +DB or less but if we look at 3 Pi we can + + align:start position:0% +DB or less but if we look at 3 Pi we can + + + align:start position:0% +DB or less but if we look at 3 Pi we can +see that this is in fact exactly down by + + align:start position:0% +see that this is in fact exactly down by + + + align:start position:0% +see that this is in fact exactly down by +15 DB and that's the way that's the way + + align:start position:0% +15 DB and that's the way that's the way + + + align:start position:0% +15 DB and that's the way that's the way +that we designed it we designed it to + + align:start position:0% +that we designed it we designed it to + + + align:start position:0% +that we designed it we designed it to +exactly meet the stop end cut off and + + align:start position:0% +exactly meet the stop end cut off and + + + align:start position:0% +exactly meet the stop end cut off and +exceed the pass fand cut + + align:start position:0% +exceed the pass fand cut + + + align:start position:0% +exceed the pass fand cut +off and then the frequency response + + align:start position:0% +off and then the frequency response + + + align:start position:0% +off and then the frequency response +continues on from there uh it's + + align:start position:0% +continues on from there uh it's + + + align:start position:0% +continues on from there uh it's +interesting in fact to compare the + + align:start position:0% +interesting in fact to compare the + + + align:start position:0% +interesting in fact to compare the +design that we got from the bilinear + + align:start position:0% +design that we got from the bilinear + + + align:start position:0% +design that we got from the bilinear +transformation with the design that we + + align:start position:0% +transformation with the design that we + + + align:start position:0% +transformation with the design that we +got previously with impulse and variance + + align:start position:0% +got previously with impulse and variance + + + align:start position:0% +got previously with impulse and variance +and let me do that by superimposing the + + align:start position:0% +and let me do that by superimposing the + + + align:start position:0% +and let me do that by superimposing the +two of them so that the one that I'm + + align:start position:0% +two of them so that the one that I'm + + + align:start position:0% +two of them so that the one that I'm +putting on now is the impulse and + + align:start position:0% +putting on now is the impulse and + + + align:start position:0% +putting on now is the impulse and +variant design and let me just lay + + align:start position:0% +variant design and let me just lay + + + align:start position:0% +variant design and let me just lay +on top of each + + align:start position:0% + + + + align:start position:0% + +other okay I think I can + + align:start position:0% +other okay I think I can + + + align:start position:0% +other okay I think I can +uh you can see incidentally that looking + + align:start position:0% +uh you can see incidentally that looking + + + align:start position:0% +uh you can see incidentally that looking +at the frequency response on a magnitude + + align:start position:0% +at the frequency response on a magnitude + + + align:start position:0% +at the frequency response on a magnitude +plot there in fact there are some + + align:start position:0% +plot there in fact there are some + + + align:start position:0% +plot there in fact there are some +differences this line has gotten a + + align:start position:0% +differences this line has gotten a + + + align:start position:0% +differences this line has gotten a +little thicker uh that is the two don't + + align:start position:0% +little thicker uh that is the two don't + + + align:start position:0% +little thicker uh that is the two don't +exactly + + align:start position:0% +exactly + + + align:start position:0% +exactly +superimpose but you can't really see the + + align:start position:0% +superimpose but you can't really see the + + + align:start position:0% +superimpose but you can't really see the +differences whereas you can when we look + + align:start position:0% +differences whereas you can when we look + + + align:start position:0% +differences whereas you can when we look +at this on a logarithmic plot in + + align:start position:0% +at this on a logarithmic plot in + + + align:start position:0% +at this on a logarithmic plot in +particular this is the frequency + + align:start position:0% +particular this is the frequency + + + align:start position:0% +particular this is the frequency +response that corresponded to the + + align:start position:0% +response that corresponded to the + + + align:start position:0% +response that corresponded to the +bilinear + + align:start position:0% +bilinear + + + align:start position:0% +bilinear +transformation this is the frequency + + align:start position:0% +transformation this is the frequency + + + align:start position:0% +transformation this is the frequency +response that corresponded to impulse + + align:start position:0% +response that corresponded to impulse + + + align:start position:0% +response that corresponded to impulse +and variance and this is in general a + + align:start position:0% +and variance and this is in general a + + + align:start position:0% +and variance and this is in general a +characteristic of the use of the + + align:start position:0% +characteristic of the use of the + + + align:start position:0% +characteristic of the use of the +bilinear + + align:start position:0% +bilinear + + + align:start position:0% +bilinear +transformation it's a result essentially + + align:start position:0% +transformation it's a result essentially + + + align:start position:0% +transformation it's a result essentially +of the frequency Distortion because + + align:start position:0% +of the frequency Distortion because + + + align:start position:0% +of the frequency Distortion because +we've taken the frequency axis in the + + align:start position:0% +we've taken the frequency axis in the + + + align:start position:0% +we've taken the frequency axis in the +the continuous time frequency axis as as + + align:start position:0% +the continuous time frequency axis as as + + + align:start position:0% +the continuous time frequency axis as as +you run along it at a constant rate it + + align:start position:0% +you run along it at a constant rate it + + + align:start position:0% +you run along it at a constant rate it +gets compressed more and more into the + + align:start position:0% +gets compressed more and more into the + + + align:start position:0% +gets compressed more and more into the +frequencies into the along the digital + + align:start position:0% +frequencies into the along the digital + + + align:start position:0% +frequencies into the along the digital +frequency axis that wasn't well said but + + align:start position:0% +frequency axis that wasn't well said but + + + align:start position:0% +frequency axis that wasn't well said but +uh what I what I really mean to say is + + align:start position:0% +uh what I what I really mean to say is + + + align:start position:0% +uh what I what I really mean to say is +as we walk along here at a constant rate + + align:start position:0% +as we walk along here at a constant rate + + + align:start position:0% +as we walk along here at a constant rate +the farther we walk the faster we're + + align:start position:0% +the farther we walk the faster we're + + + align:start position:0% +the farther we walk the faster we're +running along the J Omega axis and + + align:start position:0% +running along the J Omega axis and + + + align:start position:0% +running along the J Omega axis and +that's why in fact this will the the use + + align:start position:0% +that's why in fact this will the the use + + + align:start position:0% +that's why in fact this will the the use +of the bilinear transformation + + align:start position:0% +of the bilinear transformation + + + align:start position:0% +of the bilinear transformation +on a low pass filter will give higher + + align:start position:0% +on a low pass filter will give higher + + + align:start position:0% +on a low pass filter will give higher +frequency atten better attenuation at + + align:start position:0% +frequency atten better attenuation at + + + align:start position:0% +frequency atten better attenuation at +the higher frequencies then impulse and + + align:start position:0% +the higher frequencies then impulse and + + + align:start position:0% +the higher frequencies then impulse and +variance will and I don't know if you + + align:start position:0% +variance will and I don't know if you + + + align:start position:0% +variance will and I don't know if you +can really see the fact that the uh pass + + align:start position:0% +can really see the fact that the uh pass + + + align:start position:0% +can really see the fact that the uh pass +band specs were exceeded for + + align:start position:0% +band specs were exceeded for + + + align:start position:0% +band specs were exceeded for +the um for the impulse for the bilinear + + align:start position:0% +the um for the impulse for the bilinear + + + align:start position:0% +the um for the impulse for the bilinear +design uh in fact when you look at these + + align:start position:0% +design uh in fact when you look at these + + + align:start position:0% +design uh in fact when you look at these +view graphs in the study guide I think + + align:start position:0% +view graphs in the study guide I think + + + align:start position:0% +view graphs in the study guide I think +you'll see that for impulse and variance + + align:start position:0% +you'll see that for impulse and variance + + + align:start position:0% +you'll see that for impulse and variance +the uh curve is slightly lower than it + + align:start position:0% +the uh curve is slightly lower than it + + + align:start position:0% +the uh curve is slightly lower than it +is for the bilinear + + align:start position:0% +is for the bilinear + + + align:start position:0% +is for the bilinear +transformation okay well look this is a + + align:start position:0% +transformation okay well look this is a + + + align:start position:0% +transformation okay well look this is a +simple + + align:start position:0% +simple + + + align:start position:0% +simple +example that hopefully at least + + align:start position:0% +example that hopefully at least + + + align:start position:0% +example that hopefully at least +illustrates for you the basic procedure + + align:start position:0% +illustrates for you the basic procedure + + + align:start position:0% +illustrates for you the basic procedure +involved in carrying through a design of + + align:start position:0% +involved in carrying through a design of + + + align:start position:0% +involved in carrying through a design of +an infinite impulse response filter + + align:start position:0% +an infinite impulse response filter + + + align:start position:0% +an infinite impulse response filter +using impulse and variance and the + + align:start position:0% +using impulse and variance and the + + + align:start position:0% +using impulse and variance and the +bilinear transformation + + align:start position:0% +bilinear transformation + + + align:start position:0% +bilinear transformation +there are other examples that are + + align:start position:0% +there are other examples that are + + + align:start position:0% +there are other examples that are +considered in the text there is a + + align:start position:0% +considered in the text there is a + + + align:start position:0% +considered in the text there is a +discussion of um digital butter uh + + align:start position:0% +discussion of um digital butter uh + + + align:start position:0% +discussion of um digital butter uh +digital chbby Chef filters in other + + align:start position:0% +digital chbby Chef filters in other + + + align:start position:0% +digital chbby Chef filters in other +words digital designs beginning from an + + align:start position:0% +words digital designs beginning from an + + + align:start position:0% +words digital designs beginning from an +analog chbby Chef filter and you'll also + + align:start position:0% +analog chbby Chef filter and you'll also + + + align:start position:0% +analog chbby Chef filter and you'll also +have an opportunity to carry through + + align:start position:0% +have an opportunity to carry through + + + align:start position:0% +have an opportunity to carry through +some designs in the study + + align:start position:0% + + + + align:start position:0% + +guide a point that I would like to + + align:start position:0% +guide a point that I would like to + + + align:start position:0% +guide a point that I would like to +mention briefly is that most of the + + align:start position:0% +mention briefly is that most of the + + + align:start position:0% +mention briefly is that most of the +discussion in fact all of the discussion + + align:start position:0% +discussion in fact all of the discussion + + + align:start position:0% +discussion in fact all of the discussion +that we've gone through has focused + + align:start position:0% +that we've gone through has focused + + + align:start position:0% +that we've gone through has focused +entirely on low pass filters in fact the + + align:start position:0% +entirely on low pass filters in fact the + + + align:start position:0% +entirely on low pass filters in fact the +discussion generalizes in a fairly + + align:start position:0% +discussion generalizes in a fairly + + + align:start position:0% +discussion generalizes in a fairly +straightforward way to band pass band + + align:start position:0% +straightforward way to band pass band + + + align:start position:0% +straightforward way to band pass band +stop High Pass Etc filters in particular + + align:start position:0% +stop High Pass Etc filters in particular + + + align:start position:0% +stop High Pass Etc filters in particular +as is discussed in some detail in the + + align:start position:0% +as is discussed in some detail in the + + + align:start position:0% +as is discussed in some detail in the +text there are a class of frequency + + align:start position:0% +text there are a class of frequency + + + align:start position:0% +text there are a class of frequency +Transformations that allow low pass + + align:start position:0% +Transformations that allow low pass + + + align:start position:0% +Transformations that allow low pass +designs to get converted to band stop + + align:start position:0% +designs to get converted to band stop + + + align:start position:0% +designs to get converted to band stop +and Pass High Pass Etc + + align:start position:0% +and Pass High Pass Etc + + + align:start position:0% +and Pass High Pass Etc +designs so this concludes our discussion + + align:start position:0% +designs so this concludes our discussion + + + align:start position:0% +designs so this concludes our discussion +of design procedures + + align:start position:0% +of design procedures + + + align:start position:0% +of design procedures +for recursive or infinite impulse + + align:start position:0% +for recursive or infinite impulse + + + align:start position:0% +for recursive or infinite impulse +response digital filters in the next + + align:start position:0% +response digital filters in the next + + + align:start position:0% +response digital filters in the next +lecture + + align:start position:0% +lecture + + + align:start position:0% +lecture +I'll discuss the design of finite + + align:start position:0% +I'll discuss the design of finite + + + align:start position:0% +I'll discuss the design of finite +impulse response filters and in + + align:start position:0% +impulse response filters and in + + + align:start position:0% +impulse response filters and in +particular introduce a number of designs + + align:start position:0% +particular introduce a number of designs + + + align:start position:0% +particular introduce a number of designs +uh one of which corresponds to a class + + align:start position:0% +uh one of which corresponds to a class + + + align:start position:0% +uh one of which corresponds to a class +of algor rmic designs thank you + + align:start position:0% + + + + align:start position:0% + +[Music] \ No newline at end of file diff --git a/JvtqThS69bw.txt b/JvtqThS69bw.txt new file mode 100644 index 0000000000000000000000000000000000000000..bc49e800d157206b07b1cfa0bf532d3fdf153861 --- /dev/null +++ b/JvtqThS69bw.txt @@ -0,0 +1,1827 @@ +align:start position:0% + +in this video we'll see how to build a + + align:start position:0% +in this video we'll see how to build a + + + align:start position:0% +in this video we'll see how to build a +cart model in our let's start by reading + + align:start position:0% +cart model in our let's start by reading + + + align:start position:0% +cart model in our let's start by reading +in the data file Stephens CSV will call + + align:start position:0% +in the data file Stephens CSV will call + + + align:start position:0% +in the data file Stephens CSV will call +our data frame Stephens and use the read + + align:start position:0% +our data frame Stephens and use the read + + + align:start position:0% +our data frame Stephens and use the read +dot CSV function to read in the data + + align:start position:0% +dot CSV function to read in the data + + + align:start position:0% +dot CSV function to read in the data +file Stephens + + align:start position:0% +file Stephens + + + align:start position:0% +file Stephens +dot CSV remember to navigate to the + + align:start position:0% +dot CSV remember to navigate to the + + + align:start position:0% +dot CSV remember to navigate to the +directory on your computer containing + + align:start position:0% +directory on your computer containing + + + align:start position:0% +directory on your computer containing +the file Stephens CSV first now let's + + align:start position:0% +the file Stephens CSV first now let's + + + align:start position:0% +the file Stephens CSV first now let's +take a look at our data using the STR + + align:start position:0% +take a look at our data using the STR + + + align:start position:0% +take a look at our data using the STR +function we have five hundred and + + align:start position:0% +function we have five hundred and + + + align:start position:0% +function we have five hundred and +sixty-six observations or Supreme Court + + align:start position:0% +sixty-six observations or Supreme Court + + + align:start position:0% +sixty-six observations or Supreme Court +cases and nine different variables + + align:start position:0% +cases and nine different variables + + + align:start position:0% +cases and nine different variables +docket is just a unique identifier for + + align:start position:0% +docket is just a unique identifier for + + + align:start position:0% +docket is just a unique identifier for +each case and turn'd is the year of the + + align:start position:0% +each case and turn'd is the year of the + + + align:start position:0% +each case and turn'd is the year of the +case then we have our six independent + + align:start position:0% +case then we have our six independent + + + align:start position:0% +case then we have our six independent +variables the circuit court of origin + + align:start position:0% +variables the circuit court of origin + + + align:start position:0% +variables the circuit court of origin +the issue area of the case the type of + + align:start position:0% +the issue area of the case the type of + + + align:start position:0% +the issue area of the case the type of +petitioner the type of respondent the + + align:start position:0% +petitioner the type of respondent the + + + align:start position:0% +petitioner the type of respondent the +lower court direction and whether or not + + align:start position:0% +lower court direction and whether or not + + + align:start position:0% +lower court direction and whether or not +the petitioner argued that a law or + + align:start position:0% +the petitioner argued that a law or + + + align:start position:0% +the petitioner argued that a law or +practice was unconstitutional the last + + align:start position:0% +practice was unconstitutional the last + + + align:start position:0% +practice was unconstitutional the last +variable is our dependent variable + + align:start position:0% +variable is our dependent variable + + + align:start position:0% +variable is our dependent variable +whether or not justice Stevens voted to + + align:start position:0% +whether or not justice Stevens voted to + + + align:start position:0% +whether or not justice Stevens voted to +reverse the case one for reverse and + + align:start position:0% +reverse the case one for reverse and + + + align:start position:0% +reverse the case one for reverse and +zero for affirm now before building + + align:start position:0% +zero for affirm now before building + + + align:start position:0% +zero for affirm now before building +models we need to split our data into a + + align:start position:0% +models we need to split our data into a + + + align:start position:0% +models we need to split our data into a +training set and a testing set we'll do + + align:start position:0% +training set and a testing set we'll do + + + align:start position:0% +training set and a testing set we'll do +this using the sample dot split function + + align:start position:0% +this using the sample dot split function + + + align:start position:0% +this using the sample dot split function +like we did last week for logistic + + align:start position:0% +like we did last week for logistic + + + align:start position:0% +like we did last week for logistic +regression first we need to load the + + align:start position:0% +regression first we need to load the + + + align:start position:0% +regression first we need to load the +package CA tools with library CA tools + + align:start position:0% + + + + align:start position:0% + +now so that we all get the same split we + + align:start position:0% +now so that we all get the same split we + + + align:start position:0% +now so that we all get the same split we +need to set the seed remember that this + + align:start position:0% +need to set the seed remember that this + + + align:start position:0% +need to set the seed remember that this +can be any number as long as we all use + + align:start position:0% +can be any number as long as we all use + + + align:start position:0% +can be any number as long as we all use +the same number let's set the seed to + + align:start position:0% +the same number let's set the seed to + + + align:start position:0% +the same number let's set the seed to +3,000 now let's create our split we'll + + align:start position:0% +3,000 now let's create our split we'll + + + align:start position:0% +3,000 now let's create our split we'll +call it SPL and we'll use the sample dot + + align:start position:0% +call it SPL and we'll use the sample dot + + + align:start position:0% +call it SPL and we'll use the sample dot +split function where the first argument + + align:start position:0% +split function where the first argument + + + align:start position:0% +split function where the first argument +needs to be + + align:start position:0% +needs to be + + + align:start position:0% +needs to be +outcome variable Stephens reverse and + + align:start position:0% +outcome variable Stephens reverse and + + + align:start position:0% +outcome variable Stephens reverse and +then the second argument is the split + + align:start position:0% +then the second argument is the split + + + align:start position:0% +then the second argument is the split +ratio or the percentage of data that we + + align:start position:0% +ratio or the percentage of data that we + + + align:start position:0% +ratio or the percentage of data that we +want to put in the training set in this + + align:start position:0% +want to put in the training set in this + + + align:start position:0% +want to put in the training set in this +case we'll put 70% of the data in the + + align:start position:0% +case we'll put 70% of the data in the + + + align:start position:0% +case we'll put 70% of the data in the +training set now let's create our + + align:start position:0% +training set now let's create our + + + align:start position:0% +training set now let's create our +training and testing sets using the + + align:start position:0% +training and testing sets using the + + + align:start position:0% +training and testing sets using the +subset function we'll call our training + + align:start position:0% +subset function we'll call our training + + + align:start position:0% +subset function we'll call our training +set train and we'll take a subset of + + align:start position:0% +set train and we'll take a subset of + + + align:start position:0% +set train and we'll take a subset of +Stephens only taking the observations + + align:start position:0% +Stephens only taking the observations + + + align:start position:0% +Stephens only taking the observations +for which SPL is equal to true we'll + + align:start position:0% +for which SPL is equal to true we'll + + + align:start position:0% +for which SPL is equal to true we'll +call our testing set test and here take + + align:start position:0% +call our testing set test and here take + + + align:start position:0% +call our testing set test and here take +a subset of Stephens but this time + + align:start position:0% +a subset of Stephens but this time + + + align:start position:0% +a subset of Stephens but this time +taking the observations for which SPL is + + align:start position:0% +taking the observations for which SPL is + + + align:start position:0% +taking the observations for which SPL is +equal to false now we're ready to build + + align:start position:0% +equal to false now we're ready to build + + + align:start position:0% +equal to false now we're ready to build +our cart model first we need to install + + align:start position:0% +our cart model first we need to install + + + align:start position:0% +our cart model first we need to install +and load the are part package and the + + align:start position:0% +and load the are part package and the + + + align:start position:0% +and load the are part package and the +are part plotting package remember that + + align:start position:0% +are part plotting package remember that + + + align:start position:0% +are part plotting package remember that +to install a new package we use the + + align:start position:0% +to install a new package we use the + + + align:start position:0% +to install a new package we use the +install dot packages function and then + + align:start position:0% +install dot packages function and then + + + align:start position:0% +install dot packages function and then +in parentheses in quotes + + align:start position:0% +in parentheses in quotes + + + align:start position:0% +in parentheses in quotes +give the name of the package we want to + + align:start position:0% +give the name of the package we want to + + + align:start position:0% +give the name of the package we want to +install in this case our part after you + + align:start position:0% +install in this case our part after you + + + align:start position:0% +install in this case our part after you +hit enter a Korean mere should pop up + + align:start position:0% +hit enter a Korean mere should pop up + + + align:start position:0% +hit enter a Korean mere should pop up +asking you to pick a location near you + + align:start position:0% +asking you to pick a location near you + + + align:start position:0% +asking you to pick a location near you +go ahead and pick the appropriate + + align:start position:0% +go ahead and pick the appropriate + + + align:start position:0% +go ahead and pick the appropriate +location in my case I'll pick + + align:start position:0% +location in my case I'll pick + + + align:start position:0% +location in my case I'll pick +Pennsylvania in the United States and + + align:start position:0% +Pennsylvania in the United States and + + + align:start position:0% +Pennsylvania in the United States and +hit OK you should see some lines running + + align:start position:0% +hit OK you should see some lines running + + + align:start position:0% +hit OK you should see some lines running +your our console and then when you're + + align:start position:0% +your our console and then when you're + + + align:start position:0% +your our console and then when you're +back to the blinking cursor load the + + align:start position:0% +back to the blinking cursor load the + + + align:start position:0% +back to the blinking cursor load the +package with library our part now let's + + align:start position:0% +package with library our part now let's + + + align:start position:0% +package with library our part now let's +install the package + + align:start position:0% + + + + align:start position:0% + +our part dot plot + + align:start position:0% + + + + align:start position:0% + +again some line should run in your our + + align:start position:0% +again some line should run in your our + + + align:start position:0% +again some line should run in your our +console and when you're back to the + + align:start position:0% +console and when you're back to the + + + align:start position:0% +console and when you're back to the +blinking cursor load the package with + + align:start position:0% +blinking cursor load the package with + + + align:start position:0% +blinking cursor load the package with +library our part dot plot now we can + + align:start position:0% +library our part dot plot now we can + + + align:start position:0% +library our part dot plot now we can +create our cart model using the our part + + align:start position:0% +create our cart model using the our part + + + align:start position:0% +create our cart model using the our part +function we'll call our model Stephens + + align:start position:0% +function we'll call our model Stephens + + + align:start position:0% +function we'll call our model Stephens +tree and we'll use the art part function + + align:start position:0% +tree and we'll use the art part function + + + align:start position:0% +tree and we'll use the art part function +where the first argument is the same as + + align:start position:0% +where the first argument is the same as + + + align:start position:0% +where the first argument is the same as +if we were building a linear or logistic + + align:start position:0% +if we were building a linear or logistic + + + align:start position:0% +if we were building a linear or logistic +regression model we give our dependent + + align:start position:0% +regression model we give our dependent + + + align:start position:0% +regression model we give our dependent +variable in our case reverse followed by + + align:start position:0% +variable in our case reverse followed by + + + align:start position:0% +variable in our case reverse followed by +a tilde sign and then the independent + + align:start position:0% +a tilde sign and then the independent + + + align:start position:0% +a tilde sign and then the independent +variable is separated by plus signs so + + align:start position:0% +variable is separated by plus signs so + + + align:start position:0% +variable is separated by plus signs so +circuit plus issue plus petitioner plus + + align:start position:0% +circuit plus issue plus petitioner plus + + + align:start position:0% +circuit plus issue plus petitioner plus +respondent plus lower-court + + align:start position:0% +respondent plus lower-court + + + align:start position:0% +respondent plus lower-court +plus unconstitutional we also need to + + align:start position:0% +plus unconstitutional we also need to + + + align:start position:0% +plus unconstitutional we also need to +give our data set that should be used to + + align:start position:0% +give our data set that should be used to + + + align:start position:0% +give our data set that should be used to +build our model which in our case is + + align:start position:0% +build our model which in our case is + + + align:start position:0% +build our model which in our case is +trained now we'll give two additional + + align:start position:0% +trained now we'll give two additional + + + align:start position:0% +trained now we'll give two additional +arguments here + + align:start position:0% +arguments here + + + align:start position:0% +arguments here +the first one is method equals class + + align:start position:0% +the first one is method equals class + + + align:start position:0% +the first one is method equals class +this tells our part to build a + + align:start position:0% +this tells our part to build a + + + align:start position:0% +this tells our part to build a +classification tree instead of a + + align:start position:0% +classification tree instead of a + + + align:start position:0% +classification tree instead of a +regression tree you'll see how we can + + align:start position:0% +regression tree you'll see how we can + + + align:start position:0% +regression tree you'll see how we can +create regression trees in recitation + + align:start position:0% +create regression trees in recitation + + + align:start position:0% +create regression trees in recitation +the last argument we'll give is min + + align:start position:0% +the last argument we'll give is min + + + align:start position:0% +the last argument we'll give is min +bucket equals 25 this limits the tree so + + align:start position:0% +bucket equals 25 this limits the tree so + + + align:start position:0% +bucket equals 25 this limits the tree so +that it doesn't over fit to our training + + align:start position:0% +that it doesn't over fit to our training + + + align:start position:0% +that it doesn't over fit to our training +set we selected a value of 25 but we + + align:start position:0% +set we selected a value of 25 but we + + + align:start position:0% +set we selected a value of 25 but we +could pick a smaller or larger value + + align:start position:0% +could pick a smaller or larger value + + + align:start position:0% +could pick a smaller or larger value +we'll see another way to limit the tree + + align:start position:0% +we'll see another way to limit the tree + + + align:start position:0% +we'll see another way to limit the tree +later in this lecture now let's plot our + + align:start position:0% +later in this lecture now let's plot our + + + align:start position:0% +later in this lecture now let's plot our +tree using the PRP function where the + + align:start position:0% +tree using the PRP function where the + + + align:start position:0% +tree using the PRP function where the +only argument is the name of our model + + align:start position:0% +only argument is the name of our model + + + align:start position:0% +only argument is the name of our model +Stephens tree you should see the tree + + align:start position:0% +Stephens tree you should see the tree + + + align:start position:0% +Stephens tree you should see the tree +pop up in the graphics window the first + + align:start position:0% +pop up in the graphics window the first + + + align:start position:0% +pop up in the graphics window the first +split of our tree is whether or not the + + align:start position:0% +split of our tree is whether or not the + + + align:start position:0% +split of our tree is whether or not the +lower court decision is liberal if it is + + align:start position:0% +lower court decision is liberal if it is + + + align:start position:0% +lower court decision is liberal if it is +then we move to the left in the tree and + + align:start position:0% +then we move to the left in the tree and + + + align:start position:0% +then we move to the left in the tree and +we check the respondent if the + + align:start position:0% +we check the respondent if the + + + align:start position:0% +we check the respondent if the +respondent is a + + align:start position:0% +respondent is a + + + align:start position:0% +respondent is a +defendant injured person politician + + align:start position:0% +defendant injured person politician + + + align:start position:0% +defendant injured person politician +state or the United States we predict a + + align:start position:0% +state or the United States we predict a + + + align:start position:0% +state or the United States we predict a +zero or affirm you can see here that the + + align:start position:0% +zero or affirm you can see here that the + + + align:start position:0% +zero or affirm you can see here that the +PRP function abbreviates the values of + + align:start position:0% +PRP function abbreviates the values of + + + align:start position:0% +PRP function abbreviates the values of +the independent variables if you're not + + align:start position:0% +the independent variables if you're not + + + align:start position:0% +the independent variables if you're not +sure what the abbreviations are you + + align:start position:0% +sure what the abbreviations are you + + + align:start position:0% +sure what the abbreviations are you +could create a table of the variable to + + align:start position:0% +could create a table of the variable to + + + align:start position:0% +could create a table of the variable to +see all of the possible values PRP will + + align:start position:0% +see all of the possible values PRP will + + + align:start position:0% +see all of the possible values PRP will +select the abbreviation so that they're + + align:start position:0% +select the abbreviation so that they're + + + align:start position:0% +select the abbreviation so that they're +uniquely identifiable so if you made a + + align:start position:0% +uniquely identifiable so if you made a + + + align:start position:0% +uniquely identifiable so if you made a +table you can see that CRI stands for + + align:start position:0% +table you can see that CRI stands for + + + align:start position:0% +table you can see that CRI stands for +criminal defendant inj stands for + + align:start position:0% +criminal defendant inj stands for + + + align:start position:0% +criminal defendant inj stands for +injured person etc so now moving on in + + align:start position:0% +injured person etc so now moving on in + + + align:start position:0% +injured person etc so now moving on in +our tree if the respondent is not one of + + align:start position:0% +our tree if the respondent is not one of + + + align:start position:0% +our tree if the respondent is not one of +these types we move on to the next split + + align:start position:0% +these types we move on to the next split + + + align:start position:0% +these types we move on to the next split +and we check the petitioner if the + + align:start position:0% +and we check the petitioner if the + + + align:start position:0% +and we check the petitioner if the +petitioner is a city employee employer + + align:start position:0% +petitioner is a city employee employer + + + align:start position:0% +petitioner is a city employee employer +government official or politician then + + align:start position:0% +government official or politician then + + + align:start position:0% +government official or politician then +we predict a zero or affirm if not then + + align:start position:0% +we predict a zero or affirm if not then + + + align:start position:0% +we predict a zero or affirm if not then +we check the Circuit Court of origin if + + align:start position:0% +we check the Circuit Court of origin if + + + align:start position:0% +we check the Circuit Court of origin if +it's the tenth first third fourth DC or + + align:start position:0% +it's the tenth first third fourth DC or + + + align:start position:0% +it's the tenth first third fourth DC or +federal court then we predict zero + + align:start position:0% +federal court then we predict zero + + + align:start position:0% +federal court then we predict zero +otherwise we predict one or reverse we + + align:start position:0% +otherwise we predict one or reverse we + + + align:start position:0% +otherwise we predict one or reverse we +can repeat the same process on the other + + align:start position:0% +can repeat the same process on the other + + + align:start position:0% +can repeat the same process on the other +side of the tree if the lower court + + align:start position:0% +side of the tree if the lower court + + + align:start position:0% +side of the tree if the lower court +decision is not liberal comparing this + + align:start position:0% +decision is not liberal comparing this + + + align:start position:0% +decision is not liberal comparing this +to a logistic regression model we can + + align:start position:0% +to a logistic regression model we can + + + align:start position:0% +to a logistic regression model we can +see that it's very interpretable a car + + align:start position:0% +see that it's very interpretable a car + + + align:start position:0% +see that it's very interpretable a car +tree is a series of decision rules which + + align:start position:0% +tree is a series of decision rules which + + + align:start position:0% +tree is a series of decision rules which +can easily be explained now let's see + + align:start position:0% +can easily be explained now let's see + + + align:start position:0% +can easily be explained now let's see +how well our cart model does I'm making + + align:start position:0% +how well our cart model does I'm making + + + align:start position:0% +how well our cart model does I'm making +predictions for the test set so back in + + align:start position:0% +predictions for the test set so back in + + + align:start position:0% +predictions for the test set so back in +our our console we'll call our + + align:start position:0% +our our console we'll call our + + + align:start position:0% +our our console we'll call our +predictions predict cart and we'll use + + align:start position:0% +predictions predict cart and we'll use + + + align:start position:0% +predictions predict cart and we'll use +the predict function where the first + + align:start position:0% +the predict function where the first + + + align:start position:0% +the predict function where the first +argument is the name of our model + + align:start position:0% +argument is the name of our model + + + align:start position:0% +argument is the name of our model +Stephens tree the second argument is the + + align:start position:0% +Stephens tree the second argument is the + + + align:start position:0% +Stephens tree the second argument is the +new data we want to make predictions for + + align:start position:0% +new data we want to make predictions for + + + align:start position:0% +new data we want to make predictions for +tests and we'll add a third argument + + align:start position:0% +tests and we'll add a third argument + + + align:start position:0% +tests and we'll add a third argument +here which is type equals class + + align:start position:0% +here which is type equals class + + + align:start position:0% +here which is type equals class +we need to give this argument we're + + align:start position:0% +we need to give this argument we're + + + align:start position:0% +we need to give this argument we're +making predictions for our cart model if + + align:start position:0% +making predictions for our cart model if + + + align:start position:0% +making predictions for our cart model if +we want the majority class predictions + + align:start position:0% +we want the majority class predictions + + + align:start position:0% +we want the majority class predictions +this is like using a threshold of 0.5 + + align:start position:0% +this is like using a threshold of 0.5 + + + align:start position:0% +this is like using a threshold of 0.5 +we'll see in a few minutes how we can + + align:start position:0% +we'll see in a few minutes how we can + + + align:start position:0% +we'll see in a few minutes how we can +leave this argument out and still get + + align:start position:0% +leave this argument out and still get + + + align:start position:0% +leave this argument out and still get +probabilities from our cart model now + + align:start position:0% +probabilities from our cart model now + + + align:start position:0% +probabilities from our cart model now +let's compute the accuracy of our model + + align:start position:0% +let's compute the accuracy of our model + + + align:start position:0% +let's compute the accuracy of our model +by building a confusion matrix so we'll + + align:start position:0% +by building a confusion matrix so we'll + + + align:start position:0% +by building a confusion matrix so we'll +use the table function and first give + + align:start position:0% +use the table function and first give + + + align:start position:0% +use the table function and first give +the true outcome values test reverse and + + align:start position:0% +the true outcome values test reverse and + + + align:start position:0% +the true outcome values test reverse and +then our predictions predict cart to + + align:start position:0% +then our predictions predict cart to + + + align:start position:0% +then our predictions predict cart to +compute the accuracy we need to add up + + align:start position:0% +compute the accuracy we need to add up + + + align:start position:0% +compute the accuracy we need to add up +the observations we got correct 41 plus + + align:start position:0% +the observations we got correct 41 plus + + + align:start position:0% +the observations we got correct 41 plus +71 divided by the total number of + + align:start position:0% +71 divided by the total number of + + + align:start position:0% +71 divided by the total number of +observations in the table or the total + + align:start position:0% +observations in the table or the total + + + align:start position:0% +observations in the table or the total +number of observations in our test set + + align:start position:0% +number of observations in our test set + + + align:start position:0% +number of observations in our test set +so the accuracy of our cart model is + + align:start position:0% +so the accuracy of our cart model is + + + align:start position:0% +so the accuracy of our cart model is +0.65 9 if you were to build a logistic + + align:start position:0% +0.65 9 if you were to build a logistic + + + align:start position:0% +0.65 9 if you were to build a logistic +regression model you would get an + + align:start position:0% +regression model you would get an + + + align:start position:0% +regression model you would get an +accuracy of 0.6 65 and a baseline model + + align:start position:0% +accuracy of 0.6 65 and a baseline model + + + align:start position:0% +accuracy of 0.6 65 and a baseline model +that always predicts reverse the most + + align:start position:0% +that always predicts reverse the most + + + align:start position:0% +that always predicts reverse the most +common outcome has an accuracy of 0.5 + + align:start position:0% +common outcome has an accuracy of 0.5 + + + align:start position:0% +common outcome has an accuracy of 0.5 +4/7 so our cart model significantly + + align:start position:0% +4/7 so our cart model significantly + + + align:start position:0% +4/7 so our cart model significantly +beats the baseline and is competitive + + align:start position:0% +beats the baseline and is competitive + + + align:start position:0% +beats the baseline and is competitive +with logistic regression it's also much + + align:start position:0% +with logistic regression it's also much + + + align:start position:0% +with logistic regression it's also much +more interpretable than a logistic + + align:start position:0% +more interpretable than a logistic + + + align:start position:0% +more interpretable than a logistic +regression model would be lastly to + + align:start position:0% +regression model would be lastly to + + + align:start position:0% +regression model would be lastly to +evaluate our model let's generate an ROC + + align:start position:0% +evaluate our model let's generate an ROC + + + align:start position:0% +evaluate our model let's generate an ROC +curve for our cart model using the ROC r + + align:start position:0% +curve for our cart model using the ROC r + + + align:start position:0% +curve for our cart model using the ROC r +package first we need to load the + + align:start position:0% +package first we need to load the + + + align:start position:0% +package first we need to load the +package with the library function and + + align:start position:0% +package with the library function and + + + align:start position:0% +package with the library function and +then we need to generate our predictions + + align:start position:0% +then we need to generate our predictions + + + align:start position:0% +then we need to generate our predictions +again this time without the type equals + + align:start position:0% +again this time without the type equals + + + align:start position:0% +again this time without the type equals +class argument we'll call them predict + + align:start position:0% +class argument we'll call them predict + + + align:start position:0% +class argument we'll call them predict +ROC and we'll use the predict function + + align:start position:0% +ROC and we'll use the predict function + + + align:start position:0% +ROC and we'll use the predict function +giving just as the two arguments + + align:start position:0% +giving just as the two arguments + + + align:start position:0% +giving just as the two arguments +Stephens tree and new data equals test + + align:start position:0% +Stephens tree and new data equals test + + + align:start position:0% +Stephens tree and new data equals test +let's take a look at what this looks + + align:start position:0% +let's take a look at what this looks + + + align:start position:0% +let's take a look at what this looks +like by just typing predict ROC and + + align:start position:0% +like by just typing predict ROC and + + + align:start position:0% +like by just typing predict ROC and +hitting enter for each observation in + + align:start position:0% +hitting enter for each observation in + + + align:start position:0% +hitting enter for each observation in +the test set it gives two numbers which + + align:start position:0% +the test set it gives two numbers which + + + align:start position:0% +the test set it gives two numbers which +can be thought of as the probability of + + align:start position:0% +can be thought of as the probability of + + + align:start position:0% +can be thought of as the probability of +outcome 0 and the probability of outcome + + align:start position:0% +outcome 0 and the probability of outcome + + + align:start position:0% +outcome 0 and the probability of outcome +1 more concretely each + + align:start position:0% +1 more concretely each + + + align:start position:0% +1 more concretely each +that observation is classified into a + + align:start position:0% +that observation is classified into a + + + align:start position:0% +that observation is classified into a +subset or bucket of our cart tree these + + align:start position:0% +subset or bucket of our cart tree these + + + align:start position:0% +subset or bucket of our cart tree these +numbers give the percentage of training + + align:start position:0% +numbers give the percentage of training + + + align:start position:0% +numbers give the percentage of training +set data in that subset without comes + + align:start position:0% +set data in that subset without comes + + + align:start position:0% +set data in that subset without comes +zero and the percentage of data in the + + align:start position:0% +zero and the percentage of data in the + + + align:start position:0% +zero and the percentage of data in the +training set in that subset with outcome + + align:start position:0% +training set in that subset with outcome + + + align:start position:0% +training set in that subset with outcome +1 we'll use the second column as our + + align:start position:0% +1 we'll use the second column as our + + + align:start position:0% +1 we'll use the second column as our +probabilities to generate an ROC curve + + align:start position:0% +probabilities to generate an ROC curve + + + align:start position:0% +probabilities to generate an ROC curve +so just like we did last week for + + align:start position:0% +so just like we did last week for + + + align:start position:0% +so just like we did last week for +logistic regression + + align:start position:0% +logistic regression + + + align:start position:0% +logistic regression +we'll start by using the prediction + + align:start position:0% +we'll start by using the prediction + + + align:start position:0% +we'll start by using the prediction +function we'll call the output pred and + + align:start position:0% +function we'll call the output pred and + + + align:start position:0% +function we'll call the output pred and +then use prediction where the first + + align:start position:0% +then use prediction where the first + + + align:start position:0% +then use prediction where the first +argument is the second column of predict + + align:start position:0% +argument is the second column of predict + + + align:start position:0% +argument is the second column of predict +ROC which we can access with square + + align:start position:0% +ROC which we can access with square + + + align:start position:0% +ROC which we can access with square +brackets and the second argument is the + + align:start position:0% +brackets and the second argument is the + + + align:start position:0% +brackets and the second argument is the +true outcome values test reverse now we + + align:start position:0% +true outcome values test reverse now we + + + align:start position:0% +true outcome values test reverse now we +need to use the performance function + + align:start position:0% + + + + align:start position:0% + +where the first argument is the outcome + + align:start position:0% +where the first argument is the outcome + + + align:start position:0% +where the first argument is the outcome +of the prediction function and then the + + align:start position:0% +of the prediction function and then the + + + align:start position:0% +of the prediction function and then the +next two arguments are true positive + + align:start position:0% +next two arguments are true positive + + + align:start position:0% +next two arguments are true positive +rate and false positive rate what we + + align:start position:0% +rate and false positive rate what we + + + align:start position:0% +rate and false positive rate what we +want on the x and y-axes of our ROC + + align:start position:0% +want on the x and y-axes of our ROC + + + align:start position:0% +want on the x and y-axes of our ROC +curve now we can just plot our ROC curve + + align:start position:0% +curve now we can just plot our ROC curve + + + align:start position:0% +curve now we can just plot our ROC curve +by typing plot PD our f if you switch + + align:start position:0% +by typing plot PD our f if you switch + + + align:start position:0% +by typing plot PD our f if you switch +back to your graphics window you should + + align:start position:0% +back to your graphics window you should + + + align:start position:0% +back to your graphics window you should +see the ROC curve for our model in the + + align:start position:0% +see the ROC curve for our model in the + + + align:start position:0% +see the ROC curve for our model in the +next quick question we'll ask you to + + align:start position:0% +next quick question we'll ask you to + + + align:start position:0% +next quick question we'll ask you to +compute the test set AUC of this model \ No newline at end of file diff --git a/JxDTBbXKvyo.txt b/JxDTBbXKvyo.txt new file mode 100644 index 0000000000000000000000000000000000000000..f6aa8ff84be378cd1a6db5111df9bf55d5c3ed10 --- /dev/null +++ b/JxDTBbXKvyo.txt @@ -0,0 +1,14523 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit MIT opencourseware + + align:start position:0% +of MIT courses visit MIT opencourseware + + + align:start position:0% +of MIT courses visit MIT opencourseware +at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu I always get a little afraid + + align:start position:0% +ocw.mit.edu I always get a little afraid + + + align:start position:0% +ocw.mit.edu I always get a little afraid +when I hear somebody call me an expert + + align:start position:0% +when I hear somebody call me an expert + + + align:start position:0% +when I hear somebody call me an expert +Cu uh I think that's a term you should + + align:start position:0% +Cu uh I think that's a term you should + + + align:start position:0% +Cu uh I think that's a term you should +fear um I I want to consider myself a + + align:start position:0% +fear um I I want to consider myself a + + + align:start position:0% +fear um I I want to consider myself a +learner um and and be in that Journey + + align:start position:0% +learner um and and be in that Journey + + + align:start position:0% +learner um and and be in that Journey +with you all today uh before we get + + align:start position:0% +with you all today uh before we get + + + align:start position:0% +with you all today uh before we get +started I wanted to also uh tell us + + align:start position:0% +started I wanted to also uh tell us + + + align:start position:0% +started I wanted to also uh tell us +about a or have a guest introduce + + align:start position:0% +about a or have a guest introduce + + + align:start position:0% +about a or have a guest introduce +themselves if if she doesn't mind + + align:start position:0% +themselves if if she doesn't mind + + + align:start position:0% +themselves if if she doesn't mind +Florence hazeline is uh is the director + + align:start position:0% +Florence hazeline is uh is the director + + + align:start position:0% +Florence hazeline is uh is the director +of population studies Center for + + align:start position:0% +of population studies Center for + + + align:start position:0% +of population studies Center for +director for the center for population + + align:start position:0% +director for the center for population + + + align:start position:0% +director for the center for population +studies at the NIH and she's an adviser + + align:start position:0% +studies at the NIH and she's an adviser + + + align:start position:0% +studies at the NIH and she's an adviser +uh to to SAA + + align:start position:0% +uh to to SAA + + + align:start position:0% +uh to to SAA +and would you like to say just a few + + align:start position:0% +and would you like to say just a few + + + align:start position:0% +and would you like to say just a few +words about what you're doing and course + + align:start position:0% +words about what you're doing and course + + + align:start position:0% +words about what you're doing and course +seven and I continuously lose my brass + + align:start position:0% +seven and I continuously lose my brass + + + align:start position:0% +seven and I continuously lose my brass +wrap great so Florence is here take + + align:start position:0% +wrap great so Florence is here take + + + align:start position:0% +wrap great so Florence is here take +advantage of her she's uh just developed + + align:start position:0% +advantage of her she's uh just developed + + + align:start position:0% +advantage of her she's uh just developed +she was telling me just before class + + align:start position:0% +she was telling me just before class + + + align:start position:0% +she was telling me just before class +some some wonderful uh uh apps some some + + align:start position:0% +some some wonderful uh uh apps some some + + + align:start position:0% +some some wonderful uh uh apps some some +for iPhone and I'm guessing the iPad as + + align:start position:0% +for iPhone and I'm guessing the iPad as + + + align:start position:0% +for iPhone and I'm guessing the iPad as +well uh have to do with contraception + + align:start position:0% +well uh have to do with contraception + + + align:start position:0% +well uh have to do with contraception +really really good stuff so good + + align:start position:0% +really really good stuff so good + + + align:start position:0% +really really good stuff so good +resource for + + align:start position:0% +resource for + + + align:start position:0% +resource for +you uh we're going to be talking about + + align:start position:0% +you uh we're going to be talking about + + + align:start position:0% +you uh we're going to be talking about +quality improvement a bit today we're + + align:start position:0% +quality improvement a bit today we're + + + align:start position:0% +quality improvement a bit today we're +going to be talking about how to to + + align:start position:0% +going to be talking about how to to + + + align:start position:0% +going to be talking about how to to +engage in quality improvement um as we + + align:start position:0% +engage in quality improvement um as we + + + align:start position:0% +engage in quality improvement um as we +go if you have questions please feel + + align:start position:0% +go if you have questions please feel + + + align:start position:0% +go if you have questions please feel +free to stop me I'm very informal + + align:start position:0% +free to stop me I'm very informal + + + align:start position:0% +free to stop me I'm very informal +generally as a presenter and I'm used to + + align:start position:0% +generally as a presenter and I'm used to + + + align:start position:0% +generally as a presenter and I'm used to +presenting to groups who are working in + + align:start position:0% +presenting to groups who are working in + + + align:start position:0% +presenting to groups who are working in +small tables and less in a Stadium + + align:start position:0% +small tables and less in a Stadium + + + align:start position:0% +small tables and less in a Stadium +Theater style uh uh presentation + + align:start position:0% +Theater style uh uh presentation + + + align:start position:0% +Theater style uh uh presentation +so what we're going to cover in brief + + align:start position:0% +so what we're going to cover in brief + + + align:start position:0% +so what we're going to cover in brief +I'm going to tell you a little bit about + + align:start position:0% +I'm going to tell you a little bit about + + + align:start position:0% +I'm going to tell you a little bit about +quality improvement where it has its + + align:start position:0% +quality improvement where it has its + + + align:start position:0% +quality improvement where it has its +Origins um we'll talk about how it came + + align:start position:0% +Origins um we'll talk about how it came + + + align:start position:0% +Origins um we'll talk about how it came +to be and Healthcare I'll tell you a + + align:start position:0% +to be and Healthcare I'll tell you a + + + align:start position:0% +to be and Healthcare I'll tell you a +little bit about the institute for + + align:start position:0% +little bit about the institute for + + + align:start position:0% +little bit about the institute for +healthcare Improvement we'll talk about + + align:start position:0% +healthcare Improvement we'll talk about + + + align:start position:0% +healthcare Improvement we'll talk about +the system of profound knowledge anybody + + align:start position:0% +the system of profound knowledge anybody + + + align:start position:0% +the system of profound knowledge anybody +ever heard of the system of profound + + align:start position:0% +ever heard of the system of profound + + + align:start position:0% +ever heard of the system of profound +knowledge + + align:start position:0% +knowledge + + + align:start position:0% +knowledge +before nobody okay good so that'll be + + align:start position:0% +before nobody okay good so that'll be + + + align:start position:0% +before nobody okay good so that'll be +new we'll do a little bit on systems + + align:start position:0% +new we'll do a little bit on systems + + + align:start position:0% +new we'll do a little bit on systems +thinking and then we'll talk about + + align:start position:0% +thinking and then we'll talk about + + + align:start position:0% +thinking and then we'll talk about +something called the model for + + align:start position:0% +something called the model for + + + align:start position:0% +something called the model for +improvement we'll wrap up with that so + + align:start position:0% +improvement we'll wrap up with that so + + + align:start position:0% +improvement we'll wrap up with that so +as we go please feel free to to engage + + align:start position:0% +as we go please feel free to to engage + + + align:start position:0% +as we go please feel free to to engage +in + + align:start position:0% +in + + + align:start position:0% +in +questions all right so brief history + + align:start position:0% +questions all right so brief history + + + align:start position:0% +questions all right so brief history +there's uh two or three people that are + + align:start position:0% +there's uh two or three people that are + + + align:start position:0% +there's uh two or three people that are +incredibly important and you may + + align:start position:0% +incredibly important and you may + + + align:start position:0% +incredibly important and you may +recognize some of these faces so the the + + align:start position:0% +recognize some of these faces so the the + + + align:start position:0% +recognize some of these faces so the the +three kind of people that are often + + align:start position:0% +three kind of people that are often + + + align:start position:0% +three kind of people that are often +credited with the creation of of quality + + align:start position:0% +credited with the creation of of quality + + + align:start position:0% +credited with the creation of of quality +improvement as a as a discipline are + + align:start position:0% +improvement as a as a discipline are + + + align:start position:0% +improvement as a as a discipline are +Walter + + align:start position:0% +Walter + + + align:start position:0% +Walter +schart uh Edwards Deming and Joseph Jan + + align:start position:0% +schart uh Edwards Deming and Joseph Jan + + + align:start position:0% +schart uh Edwards Deming and Joseph Jan +both Deming and Jiran were students of + + align:start position:0% +both Deming and Jiran were students of + + + align:start position:0% +both Deming and Jiran were students of +Walter schuhart and I think Leo + + align:start position:0% +Walter schuhart and I think Leo + + + align:start position:0% +Walter schuhart and I think Leo +mentioned a bit about this before but + + align:start position:0% +mentioned a bit about this before but + + + align:start position:0% +mentioned a bit about this before but +Walter schuhart uh was a statistician + + align:start position:0% +Walter schuhart uh was a statistician + + + align:start position:0% +Walter schuhart uh was a statistician +who was working in the early part of the + + align:start position:0% +who was working in the early part of the + + + align:start position:0% +who was working in the early part of the +last century and he is responsible for + + align:start position:0% +last century and he is responsible for + + + align:start position:0% +last century and he is responsible for +for something we call statistical + + align:start position:0% +for something we call statistical + + + align:start position:0% +for something we call statistical +process control methods so he uh took uh + + align:start position:0% +process control methods so he uh took uh + + + align:start position:0% +process control methods so he uh took uh +statistics in a New Direction took it + + align:start position:0% +statistics in a New Direction took it + + + align:start position:0% +statistics in a New Direction took it +away from classical uh sort of + + align:start position:0% +away from classical uh sort of + + + align:start position:0% +away from classical uh sort of +descriptive statistics and looked at how + + align:start position:0% +descriptive statistics and looked at how + + + align:start position:0% +descriptive statistics and looked at how +we could understand systems over time + + align:start position:0% +we could understand systems over time + + + align:start position:0% +we could understand systems over time +could we get to a place where we could + + align:start position:0% +could we get to a place where we could + + + align:start position:0% +could we get to a place where we could +understand performance and actually + + align:start position:0% +understand performance and actually + + + align:start position:0% +understand performance and actually +predict Performance Based on stable + + align:start position:0% +predict Performance Based on stable + + + align:start position:0% +predict Performance Based on stable +systems so this is Walter + + align:start position:0% +systems so this is Walter + + + align:start position:0% +systems so this is Walter +schart and he was a a very very deep + + align:start position:0% +schart and he was a a very very deep + + + align:start position:0% +schart and he was a a very very deep +thinker in that regard although he + + align:start position:0% +thinker in that regard although he + + + align:start position:0% +thinker in that regard although he +wasn't really interested in healthcare + + align:start position:0% +wasn't really interested in healthcare + + + align:start position:0% +wasn't really interested in healthcare +he was mostly focused on + + align:start position:0% +he was mostly focused on + + + align:start position:0% +he was mostly focused on +manufacturing his uh pupil and the + + align:start position:0% +manufacturing his uh pupil and the + + + align:start position:0% +manufacturing his uh pupil and the +person we're going to talk most about + + align:start position:0% +person we're going to talk most about + + + align:start position:0% +person we're going to talk most about +today was uh Edwards Deming and Deming + + align:start position:0% +today was uh Edwards Deming and Deming + + + align:start position:0% +today was uh Edwards Deming and Deming +took it a step further he was also a + + align:start position:0% +took it a step further he was also a + + + align:start position:0% +took it a step further he was also a +statistician he learned quite a lot from + + align:start position:0% +statistician he learned quite a lot from + + + align:start position:0% +statistician he learned quite a lot from +Walter schuhart and they wrote a couple + + align:start position:0% +Walter schuhart and they wrote a couple + + + align:start position:0% +Walter schuhart and they wrote a couple +of books together on the subject of + + align:start position:0% +of books together on the subject of + + + align:start position:0% +of books together on the subject of +statistical process control but Deming + + align:start position:0% +statistical process control but Deming + + + align:start position:0% +statistical process control but Deming +actually thought that there were some + + align:start position:0% +actually thought that there were some + + + align:start position:0% +actually thought that there were some +other things that were going to be + + align:start position:0% +other things that were going to be + + + align:start position:0% +other things that were going to be +critically important not only to + + align:start position:0% +critically important not only to + + + align:start position:0% +critically important not only to +understanding systems but if you wanted + + align:start position:0% +understanding systems but if you wanted + + + align:start position:0% +understanding systems but if you wanted +to change systems if you wanted to make + + align:start position:0% +to change systems if you wanted to make + + + align:start position:0% +to change systems if you wanted to make +them better what was the knowledge that + + align:start position:0% +them better what was the knowledge that + + + align:start position:0% +them better what was the knowledge that +you needed to leverage in order to do + + align:start position:0% +you needed to leverage in order to do + + + align:start position:0% +you needed to leverage in order to do +that right and and we're going to talk + + align:start position:0% +that right and and we're going to talk + + + align:start position:0% +that right and and we're going to talk +more about that and and he gave us what + + align:start position:0% +more about that and and he gave us what + + + align:start position:0% +more about that and and he gave us what +we call the system of profound knowledge + + align:start position:0% +we call the system of profound knowledge + + + align:start position:0% +we call the system of profound knowledge +Joseph Jan was also a very important + + align:start position:0% +Joseph Jan was also a very important + + + align:start position:0% +Joseph Jan was also a very important +thinker at the same time period um and + + align:start position:0% +thinker at the same time period um and + + + align:start position:0% +thinker at the same time period um and +he focused his efforts on three + + align:start position:0% +he focused his efforts on three + + + align:start position:0% +he focused his efforts on three +different things whereas Deming was + + align:start position:0% +different things whereas Deming was + + + align:start position:0% +different things whereas Deming was +focused almost exclusively on quality + + align:start position:0% +focused almost exclusively on quality + + + align:start position:0% +focused almost exclusively on quality +improvement Jiran had what we call the + + align:start position:0% +improvement Jiran had what we call the + + + align:start position:0% +improvement Jiran had what we call the +Duran Trilogy he was focused on three + + align:start position:0% +Duran Trilogy he was focused on three + + + align:start position:0% +Duran Trilogy he was focused on three +things quality assurance quality + + align:start position:0% +things quality assurance quality + + + align:start position:0% +things quality assurance quality +improvement and quality design and so he + + align:start position:0% +improvement and quality design and so he + + + align:start position:0% +improvement and quality design and so he +was interested in designing systems + + align:start position:0% +was interested in designing systems + + + align:start position:0% +was interested in designing systems +assuring that they were achieving the + + align:start position:0% +assuring that they were achieving the + + + align:start position:0% +assuring that they were achieving the +the the stability that was called called + + align:start position:0% +the the stability that was called called + + + align:start position:0% +the the stability that was called called +for by the customer and then figuring + + align:start position:0% +for by the customer and then figuring + + + align:start position:0% +for by the customer and then figuring +out how to improve upon the quality of + + align:start position:0% +out how to improve upon the quality of + + + align:start position:0% +out how to improve upon the quality of +the product or service that that that + + align:start position:0% +the product or service that that that + + + align:start position:0% +the product or service that that that +system was was seeking to serve okay so + + align:start position:0% +system was was seeking to serve okay so + + + align:start position:0% +system was was seeking to serve okay so +those are sort of three three important + + align:start position:0% +those are sort of three three important + + + align:start position:0% +those are sort of three three important +people uh Deming did a lot of his work + + align:start position:0% +people uh Deming did a lot of his work + + + align:start position:0% +people uh Deming did a lot of his work +in Japan after World War II he worked + + align:start position:0% +in Japan after World War II he worked + + + align:start position:0% +in Japan after World War II he worked +with our US military during the World + + align:start position:0% +with our US military during the World + + + align:start position:0% +with our US military during the World +War II and then afterwards with the + + align:start position:0% +War II and then afterwards with the + + + align:start position:0% +War II and then afterwards with the +rebuilding of the Japanese economy have + + align:start position:0% +rebuilding of the Japanese economy have + + + align:start position:0% +rebuilding of the Japanese economy have +people heard of of Deming before couple + + align:start position:0% +people heard of of Deming before couple + + + align:start position:0% +people heard of of Deming before couple +people right yeah good uh so uh how many + + align:start position:0% +people right yeah good uh so uh how many + + + align:start position:0% +people right yeah good uh so uh how many +have heard of Toyota production system + + align:start position:0% +have heard of Toyota production system + + + align:start position:0% +have heard of Toyota production system +or lean manufacturing more people have + + align:start position:0% +or lean manufacturing more people have + + + align:start position:0% +or lean manufacturing more people have +heard of that all of that is an + + align:start position:0% +heard of that all of that is an + + + align:start position:0% +heard of that all of that is an +outgrowth of what he started in Japan in + + align:start position:0% +outgrowth of what he started in Japan in + + + align:start position:0% +outgrowth of what he started in Japan in +in the early 1950s and we're going to + + align:start position:0% +in the early 1950s and we're going to + + + align:start position:0% +in the early 1950s and we're going to +talk a bit about that today as well + + align:start position:0% +talk a bit about that today as well + + + align:start position:0% +talk a bit about that today as well +so Deming system of profound + + align:start position:0% +so Deming system of profound + + + align:start position:0% +so Deming system of profound +knowledge most aply described in his + + align:start position:0% +knowledge most aply described in his + + + align:start position:0% +knowledge most aply described in his +book the new economics which was + + align:start position:0% +book the new economics which was + + + align:start position:0% +book the new economics which was +published in the early 90s just shortly + + align:start position:0% +published in the early 90s just shortly + + + align:start position:0% +published in the early 90s just shortly +before his death Deming was a he was a + + align:start position:0% +before his death Deming was a he was a + + + align:start position:0% +before his death Deming was a he was a +person who was absolutely passionate + + align:start position:0% +person who was absolutely passionate + + + align:start position:0% +person who was absolutely passionate +about quality improvement uh he lived to + + align:start position:0% +about quality improvement uh he lived to + + + align:start position:0% +about quality improvement uh he lived to +be 93 years old he gave his last 4-day + + align:start position:0% +be 93 years old he gave his last 4-day + + + align:start position:0% +be 93 years old he gave his last 4-day +seminar on quality improvement at the + + align:start position:0% +seminar on quality improvement at the + + + align:start position:0% +seminar on quality improvement at the +age of 93 2 weeks before he passed away + + align:start position:0% +age of 93 2 weeks before he passed away + + + align:start position:0% +age of 93 2 weeks before he passed away +from a wheelchair on oxygen he made it + + align:start position:0% +from a wheelchair on oxygen he made it + + + align:start position:0% +from a wheelchair on oxygen he made it +his life's mission to focus on improving + + align:start position:0% +his life's mission to focus on improving + + + align:start position:0% +his life's mission to focus on improving +systems he felt that there was a + + align:start position:0% +systems he felt that there was a + + + align:start position:0% +systems he felt that there was a +tremendous amount of waste uh and + + align:start position:0% +tremendous amount of waste uh and + + + align:start position:0% +tremendous amount of waste uh and +inefficiency that existed in systems + + align:start position:0% +inefficiency that existed in systems + + + align:start position:0% +inefficiency that existed in systems +whether they be manufacturing service + + align:start position:0% +whether they be manufacturing service + + + align:start position:0% +whether they be manufacturing service +industry or later in his life during + + align:start position:0% +industry or later in his life during + + + align:start position:0% +industry or later in his life during +sort of the last decade of his life in + + align:start position:0% +sort of the last decade of his life in + + + align:start position:0% +sort of the last decade of his life in +healthcare um and he gave us uh the + + align:start position:0% +healthcare um and he gave us uh the + + + align:start position:0% +healthcare um and he gave us uh the +system of profound knowledge which I'm + + align:start position:0% +system of profound knowledge which I'm + + + align:start position:0% +system of profound knowledge which I'm +going to describe in a second + + align:start position:0% +going to describe in a second + + + align:start position:0% +going to describe in a second +before I do that though I want to talk a + + align:start position:0% +before I do that though I want to talk a + + + align:start position:0% +before I do that though I want to talk a +little bit about the institute for + + align:start position:0% +little bit about the institute for + + + align:start position:0% +little bit about the institute for +healthcare Improvement so uh Deming was + + align:start position:0% +healthcare Improvement so uh Deming was + + + align:start position:0% +healthcare Improvement so uh Deming was +holding one of his 4day seminars in 1987 + + align:start position:0% +holding one of his 4day seminars in 1987 + + + align:start position:0% +holding one of his 4day seminars in 1987 +and there was a doctor in the audience + + align:start position:0% +and there was a doctor in the audience + + + align:start position:0% +and there was a doctor in the audience +by the name of Don Berwick who uh Leo + + align:start position:0% +by the name of Don Berwick who uh Leo + + + align:start position:0% +by the name of Don Berwick who uh Leo +introduced us to a couple weeks + + align:start position:0% +introduced us to a couple weeks + + + align:start position:0% +introduced us to a couple weeks +ago Don was uh working here in in Boston + + align:start position:0% +ago Don was uh working here in in Boston + + + align:start position:0% +ago Don was uh working here in in Boston +as a pediatrician and he was seeing that + + align:start position:0% +as a pediatrician and he was seeing that + + + align:start position:0% +as a pediatrician and he was seeing that +a lot of patients were being harmed uh + + align:start position:0% +a lot of patients were being harmed uh + + + align:start position:0% +a lot of patients were being harmed uh +in the hospitals where he was working + + align:start position:0% +in the hospitals where he was working + + + align:start position:0% +in the hospitals where he was working +and he also knew internally no matter + + align:start position:0% +and he also knew internally no matter + + + align:start position:0% +and he also knew internally no matter +how hard he worked he couldn't always + + align:start position:0% +how hard he worked he couldn't always + + + align:start position:0% +how hard he worked he couldn't always +provide the same level of quality of + + align:start position:0% +provide the same level of quality of + + + align:start position:0% +provide the same level of quality of +care to every one of his patients and + + align:start position:0% +care to every one of his patients and + + + align:start position:0% +care to every one of his patients and +that bothered him as an individual right + + align:start position:0% +that bothered him as an individual right + + + align:start position:0% +that bothered him as an individual right +and so he was looking for answers for + + align:start position:0% +and so he was looking for answers for + + + align:start position:0% +and so he was looking for answers for +that and he actually went and and and + + align:start position:0% +that and he actually went and and and + + + align:start position:0% +that and he actually went and and and +attended Dr deming's seminar for four + + align:start position:0% +attended Dr deming's seminar for four + + + align:start position:0% +attended Dr deming's seminar for four +days after the first day he thought this + + align:start position:0% +days after the first day he thought this + + + align:start position:0% +days after the first day he thought this +guy is crazy got on a plane flew back to + + align:start position:0% +guy is crazy got on a plane flew back to + + + align:start position:0% +guy is crazy got on a plane flew back to +Boston in the middle of the night he had + + align:start position:0% +Boston in the middle of the night he had + + + align:start position:0% +Boston in the middle of the night he had +this Epiphany that actually there's + + align:start position:0% +this Epiphany that actually there's + + + align:start position:0% +this Epiphany that actually there's +something to this system's thinking + + align:start position:0% +something to this system's thinking + + + align:start position:0% +something to this system's thinking +there's something to quality improvement + + align:start position:0% +there's something to quality improvement + + + align:start position:0% +there's something to quality improvement +that I need to learn about he flew back + + align:start position:0% +that I need to learn about he flew back + + + align:start position:0% +that I need to learn about he flew back +the following morning on the early + + align:start position:0% +the following morning on the early + + + align:start position:0% +the following morning on the early +morning flight finished the seminar and + + align:start position:0% +morning flight finished the seminar and + + + align:start position:0% +morning flight finished the seminar and +at the end of that he developed an idea + + align:start position:0% +at the end of that he developed an idea + + + align:start position:0% +at the end of that he developed an idea +for a demonstration project and he + + align:start position:0% +for a demonstration project and he + + + align:start position:0% +for a demonstration project and he +sought some funding and he partnered 16 + + align:start position:0% +sought some funding and he partnered 16 + + + align:start position:0% +sought some funding and he partnered 16 +hospitals in the in the Boston area with + + align:start position:0% +hospitals in the in the Boston area with + + + align:start position:0% +hospitals in the in the Boston area with +industry leaders in quality improvement + + align:start position:0% +industry leaders in quality improvement + + + align:start position:0% +industry leaders in quality improvement +people who had been using uh Dr deming's + + align:start position:0% +people who had been using uh Dr deming's + + + align:start position:0% +people who had been using uh Dr deming's +methods for years and years so he would + + align:start position:0% +methods for years and years so he would + + + align:start position:0% +methods for years and years so he would +partner people with uh electric + + align:start position:0% +partner people with uh electric + + + align:start position:0% +partner people with uh electric +companies and manufacturing companies to + + align:start position:0% +companies and manufacturing companies to + + + align:start position:0% +companies and manufacturing companies to +see how they could learn about quality + + align:start position:0% +see how they could learn about quality + + + align:start position:0% +see how they could learn about quality +improvement and bring that into + + align:start position:0% +improvement and bring that into + + + align:start position:0% +improvement and bring that into +Healthcare that demonstration proc + + align:start position:0% +Healthcare that demonstration proc + + + align:start position:0% +Healthcare that demonstration proc +project lasted a couple of years and at + + align:start position:0% +project lasted a couple of years and at + + + align:start position:0% +project lasted a couple of years and at +the end of it there was a lot of really + + align:start position:0% +the end of it there was a lot of really + + + align:start position:0% +the end of it there was a lot of really +good learning about how we could improve + + align:start position:0% +good learning about how we could improve + + + align:start position:0% +good learning about how we could improve +uh systems of healthare so uh we decided + + align:start position:0% +uh systems of healthare so uh we decided + + + align:start position:0% +uh systems of healthare so uh we decided +to create ihi at that time so that was + + align:start position:0% +to create ihi at that time so that was + + + align:start position:0% +to create ihi at that time so that was +in 1991 and ihi is is based here in + + align:start position:0% +in 1991 and ihi is is based here in + + + align:start position:0% +in 1991 and ihi is is based here in +Harvard Square has been working on + + align:start position:0% +Harvard Square has been working on + + + align:start position:0% +Harvard Square has been working on +improving Health Care Systems using uh + + align:start position:0% +improving Health Care Systems using uh + + + align:start position:0% +improving Health Care Systems using uh +uh quality improvement methods for the + + align:start position:0% +uh quality improvement methods for the + + + align:start position:0% +uh quality improvement methods for the +last 20 years or so so I've had the + + align:start position:0% +last 20 years or so so I've had the + + + align:start position:0% +last 20 years or so so I've had the +opportunity to work for them for the + + align:start position:0% +opportunity to work for them for the + + + align:start position:0% +opportunity to work for them for the +last five years or so and as Elliot + + align:start position:0% +last five years or so and as Elliot + + + align:start position:0% +last five years or so and as Elliot +pointed out I've been doing that mostly + + align:start position:0% +pointed out I've been doing that mostly + + + align:start position:0% +pointed out I've been doing that mostly +in resource constraints environments um + + align:start position:0% +in resource constraints environments um + + + align:start position:0% +in resource constraints environments um +and I think that's really where quality + + align:start position:0% +and I think that's really where quality + + + align:start position:0% +and I think that's really where quality +improvement uh is at its best in places + + align:start position:0% +improvement uh is at its best in places + + + align:start position:0% +improvement uh is at its best in places +where you've got to optimize what you + + align:start position:0% +where you've got to optimize what you + + + align:start position:0% +where you've got to optimize what you +have because you don't have anything + + align:start position:0% +have because you don't have anything + + + align:start position:0% +have because you don't have anything +extra to to give so what is quality + + align:start position:0% +extra to to give so what is quality + + + align:start position:0% +extra to to give so what is quality +improvement what is the system of + + align:start position:0% +improvement what is the system of + + + align:start position:0% +improvement what is the system of +profound knowledge okay system of + + align:start position:0% +profound knowledge okay system of + + + align:start position:0% +profound knowledge okay system of +profound knowledge is a way of looking + + align:start position:0% +profound knowledge is a way of looking + + + align:start position:0% +profound knowledge is a way of looking +at an organization or a system that's + + align:start position:0% +at an organization or a system that's + + + align:start position:0% +at an organization or a system that's +trying to provide a service so if I'm + + align:start position:0% +trying to provide a service so if I'm + + + align:start position:0% +trying to provide a service so if I'm +looking at a Health Care System a single + + align:start position:0% +looking at a Health Care System a single + + + align:start position:0% +looking at a Health Care System a single +Hospital a clinic or even a whole + + align:start position:0% +Hospital a clinic or even a whole + + + align:start position:0% +Hospital a clinic or even a whole +healthare system right I can use this + + align:start position:0% +healthare system right I can use this + + + align:start position:0% +healthare system right I can use this +sort of a lens if you + + align:start position:0% +sort of a lens if you + + + align:start position:0% +sort of a lens if you +will as a way to understand performance + + align:start position:0% +will as a way to understand performance + + + align:start position:0% +will as a way to understand performance +okay and Demi argued that there were + + align:start position:0% +okay and Demi argued that there were + + + align:start position:0% +okay and Demi argued that there were +four really key components here okay the + + align:start position:0% +four really key components here okay the + + + align:start position:0% +four really key components here okay the +first was appreciation of the system do + + align:start position:0% +first was appreciation of the system do + + + align:start position:0% +first was appreciation of the system do +you have a way of viewing all of the + + align:start position:0% +you have a way of viewing all of the + + + align:start position:0% +you have a way of viewing all of the +processes that exist within a system all + + align:start position:0% +processes that exist within a system all + + + align:start position:0% +processes that exist within a system all +of the work that is happening on a + + align:start position:0% +of the work that is happening on a + + + align:start position:0% +of the work that is happening on a +day-to-day basis work that's happening + + align:start position:0% +day-to-day basis work that's happening + + + align:start position:0% +day-to-day basis work that's happening +between caregivers and patients between + + align:start position:0% +between caregivers and patients between + + + align:start position:0% +between caregivers and patients between +managers and caregivers between support + + align:start position:0% +managers and caregivers between support + + + align:start position:0% +managers and caregivers between support +staff and each other right all the + + align:start position:0% +staff and each other right all the + + + align:start position:0% +staff and each other right all the +different things that are happening do + + align:start position:0% +different things that are happening do + + + align:start position:0% +different things that are happening do +you have a way of articulating that I'm + + align:start position:0% +you have a way of articulating that I'm + + + align:start position:0% +you have a way of articulating that I'm +actually going to introduce you to to a + + align:start position:0% +actually going to introduce you to to a + + + align:start position:0% +actually going to introduce you to to a +mechanism for that this morning so + + align:start position:0% +mechanism for that this morning so + + + align:start position:0% +mechanism for that this morning so +appreciation of the system do you have + + align:start position:0% +appreciation of the system do you have + + + align:start position:0% +appreciation of the system do you have +that view can you see everything at once + + align:start position:0% +that view can you see everything at once + + + align:start position:0% +that view can you see everything at once +because if you get busy trying to + + align:start position:0% +because if you get busy trying to + + + align:start position:0% +because if you get busy trying to +improve one thing you can actually sub + + align:start position:0% +improve one thing you can actually sub + + + align:start position:0% +improve one thing you can actually sub +optimize the whole system he also knew + + align:start position:0% +optimize the whole system he also knew + + + align:start position:0% +optimize the whole system he also knew +that there was the importance of data + + align:start position:0% +that there was the importance of data + + + align:start position:0% +that there was the importance of data +right the importance of of understanding + + align:start position:0% +right the importance of of understanding + + + align:start position:0% +right the importance of of understanding +variation and understanding stability + + align:start position:0% +variation and understanding stability + + + align:start position:0% +variation and understanding stability +that's where he got his start with + + align:start position:0% +that's where he got his start with + + + align:start position:0% +that's where he got his start with +Walter shuart so he he knew that you + + align:start position:0% +Walter shuart so he he knew that you + + + align:start position:0% +Walter shuart so he he knew that you +needed to be able to understand each + + align:start position:0% +needed to be able to understand each + + + align:start position:0% +needed to be able to understand each +process and measure it and understand if + + align:start position:0% +process and measure it and understand if + + + align:start position:0% +process and measure it and understand if +it was predictably performing into the + + align:start position:0% +it was predictably performing into the + + + align:start position:0% +it was predictably performing into the +future we're not going to touch so much + + align:start position:0% +future we're not going to touch so much + + + align:start position:0% +future we're not going to touch so much +on that today although I would like to I + + align:start position:0% +on that today although I would like to I + + + align:start position:0% +on that today although I would like to I +think it's a really fun topic Deming + + align:start position:0% +think it's a really fun topic Deming + + + align:start position:0% +think it's a really fun topic Deming +also knew that psychology was incredibly + + align:start position:0% +also knew that psychology was incredibly + + + align:start position:0% +also knew that psychology was incredibly +important motivation what gets people to + + align:start position:0% +important motivation what gets people to + + + align:start position:0% +important motivation what gets people to +work in the morning what gets them doing + + align:start position:0% +work in the morning what gets them doing + + + align:start position:0% +work in the morning what gets them doing +things what gets them excited about + + align:start position:0% +things what gets them excited about + + + align:start position:0% +things what gets them excited about +their work right so he knew that + + align:start position:0% +their work right so he knew that + + + align:start position:0% +their work right so he knew that +psychology was critically important and + + align:start position:0% +psychology was critically important and + + + align:start position:0% +psychology was critically important and +and there's a piece of this which is + + align:start position:0% +and there's a piece of this which is + + + align:start position:0% +and there's a piece of this which is +sort of the culture of an organization + + align:start position:0% +sort of the culture of an organization + + + align:start position:0% +sort of the culture of an organization +is it a is it a punitive organization + + align:start position:0% +is it a is it a punitive organization + + + align:start position:0% +is it a is it a punitive organization +internally is it one that rewards + + align:start position:0% +internally is it one that rewards + + + align:start position:0% +internally is it one that rewards +Innovation is it a learning organization + + align:start position:0% +Innovation is it a learning organization + + + align:start position:0% +Innovation is it a learning organization +that encourages people to constantly be + + align:start position:0% +that encourages people to constantly be + + + align:start position:0% +that encourages people to constantly be +testing and learning failing often right + + align:start position:0% +testing and learning failing often right + + + align:start position:0% +testing and learning failing often right +so he knew that that was going to be + + align:start position:0% +so he knew that that was going to be + + + align:start position:0% +so he knew that that was going to be +critically important and the last piece + + align:start position:0% +critically important and the last piece + + + align:start position:0% +critically important and the last piece +he had was the theory of knowledge we're + + align:start position:0% +he had was the theory of knowledge we're + + + align:start position:0% +he had was the theory of knowledge we're +going to talk a bit about that as well + + align:start position:0% +going to talk a bit about that as well + + + align:start position:0% +going to talk a bit about that as well +today theory of knowledge sometimes + + align:start position:0% +today theory of knowledge sometimes + + + align:start position:0% +today theory of knowledge sometimes +people call it epistemology uh sometimes + + align:start position:0% +people call it epistemology uh sometimes + + + align:start position:0% +people call it epistemology uh sometimes +talk about the scientific method I like + + align:start position:0% +talk about the scientific method I like + + + align:start position:0% +talk about the scientific method I like +to think of it this as this way is uh + + align:start position:0% +to think of it this as this way is uh + + + align:start position:0% +to think of it this as this way is uh +can you articulate what you believe + + align:start position:0% +can you articulate what you believe + + + align:start position:0% +can you articulate what you believe +about why things are the way that they + + align:start position:0% +about why things are the way that they + + + align:start position:0% +about why things are the way that they +are can you do + + align:start position:0% +are can you do + + + align:start position:0% +are can you do +that if you can that's great because it + + align:start position:0% +that if you can that's great because it + + + align:start position:0% +that if you can that's great because it +gives you a testable starting place + + align:start position:0% +gives you a testable starting place + + + align:start position:0% +gives you a testable starting place +right because whatever you believe is + + align:start position:0% +right because whatever you believe is + + + align:start position:0% +right because whatever you believe is +going to influence what you decide to + + align:start position:0% +going to influence what you decide to + + + align:start position:0% +going to influence what you decide to +change when you go to improve a system + + align:start position:0% +change when you go to improve a system + + + align:start position:0% +change when you go to improve a system +if I am doing some work in South Africa + + align:start position:0% +if I am doing some work in South Africa + + + align:start position:0% +if I am doing some work in South Africa +and I believe at one particular hospital + + align:start position:0% +and I believe at one particular hospital + + + align:start position:0% +and I believe at one particular hospital +that the reason we have poor outcomes + + align:start position:0% +that the reason we have poor outcomes + + + align:start position:0% +that the reason we have poor outcomes +for our patients is because nurses are + + align:start position:0% +for our patients is because nurses are + + + align:start position:0% +for our patients is because nurses are +lazy + + align:start position:0% +lazy + + + align:start position:0% +lazy +then that's going to control what I + + align:start position:0% +then that's going to control what I + + + align:start position:0% +then that's going to control what I +decide to change I'm going to do + + align:start position:0% +decide to change I'm going to do + + + align:start position:0% +decide to change I'm going to do +something to remove the laziness of + + align:start position:0% +something to remove the laziness of + + + align:start position:0% +something to remove the laziness of +nurses now I do not actually believe + + align:start position:0% +nurses now I do not actually believe + + + align:start position:0% +nurses now I do not actually believe +nurses are lazy I think they're the + + align:start position:0% +nurses are lazy I think they're the + + + align:start position:0% +nurses are lazy I think they're the +hardest working people in healthcare but + + align:start position:0% +hardest working people in healthcare but + + + align:start position:0% +hardest working people in healthcare but +if I believe that if that's my theory if + + align:start position:0% +if I believe that if that's my theory if + + + align:start position:0% +if I believe that if that's my theory if +that's my starting place then that + + align:start position:0% +that's my starting place then that + + + align:start position:0% +that's my starting place then that +changes what I decide to change in a + + align:start position:0% +changes what I decide to change in a + + + align:start position:0% +changes what I decide to change in a +system if I instead think that it's a + + align:start position:0% +system if I instead think that it's a + + + align:start position:0% +system if I instead think that it's a +process orientation problem or it's a + + align:start position:0% +process orientation problem or it's a + + + align:start position:0% +process orientation problem or it's a +problem with Physicians or it's a + + align:start position:0% +problem with Physicians or it's a + + + align:start position:0% +problem with Physicians or it's a +problem with technology or resources + + align:start position:0% +problem with technology or resources + + + align:start position:0% +problem with technology or resources +then that's what I'm going to go after a + + align:start position:0% +then that's what I'm going to go after a + + + align:start position:0% +then that's what I'm going to go after a +lot of people never get to the place + + align:start position:0% +lot of people never get to the place + + + align:start position:0% +lot of people never get to the place +where they are articulate what they + + align:start position:0% +where they are articulate what they + + + align:start position:0% +where they are articulate what they +believe about why things are the way + + align:start position:0% +believe about why things are the way + + + align:start position:0% +believe about why things are the way +that they are they internalize + + align:start position:0% +that they are they internalize + + + align:start position:0% +that they are they internalize +assumptions and then they start towards + + align:start position:0% +assumptions and then they start towards + + + align:start position:0% +assumptions and then they start towards +Solutions based on those + + align:start position:0% +Solutions based on those + + + align:start position:0% +Solutions based on those +assumptions often we hear about + + align:start position:0% +assumptions often we hear about + + + align:start position:0% +assumptions often we hear about +especially in resource constrained + + align:start position:0% +especially in resource constrained + + + align:start position:0% +especially in resource constrained +environments what tell you what we need + + align:start position:0% +environments what tell you what we need + + + align:start position:0% +environments what tell you what we need +we need more hospitals we need to build + + align:start position:0% +we need more hospitals we need to build + + + align:start position:0% +we need more hospitals we need to build +more + + align:start position:0% +more + + + align:start position:0% +more +hospitals right what's the underlying + + align:start position:0% +hospitals right what's the underlying + + + align:start position:0% +hospitals right what's the underlying +assumption that the infrastructure is + + align:start position:0% +assumption that the infrastructure is + + + align:start position:0% +assumption that the infrastructure is +inadequate right and then there is even + + align:start position:0% +inadequate right and then there is even + + + align:start position:0% +inadequate right and then there is even +further assumptions behind that about + + align:start position:0% +further assumptions behind that about + + + align:start position:0% +further assumptions behind that about +why the infrastructure is inadequate + + align:start position:0% +why the infrastructure is inadequate + + + align:start position:0% +why the infrastructure is inadequate +right we hear we need more healthcare + + align:start position:0% +right we hear we need more healthcare + + + align:start position:0% +right we hear we need more healthcare +workers right we need need more money + + align:start position:0% +workers right we need need more money + + + align:start position:0% +workers right we need need more money +what we know from us healthc care is + + align:start position:0% +what we know from us healthc care is + + + align:start position:0% +what we know from us healthc care is +that's not likely the case right Leo + + align:start position:0% +that's not likely the case right Leo + + + align:start position:0% +that's not likely the case right Leo +told us about us healthare right we + + align:start position:0% +told us about us healthare right we + + + align:start position:0% +told us about us healthare right we +spend twice as much money as the next + + align:start position:0% +spend twice as much money as the next + + + align:start position:0% +spend twice as much money as the next +country to get not as good care so it + + align:start position:0% +country to get not as good care so it + + + align:start position:0% +country to get not as good care so it +may not be a resource issue but we need + + align:start position:0% +may not be a resource issue but we need + + + align:start position:0% +may not be a resource issue but we need +to question that if that's our starting + + align:start position:0% +to question that if that's our starting + + + align:start position:0% +to question that if that's our starting +place we need a place to to start + + align:start position:0% +place we need a place to to start + + + align:start position:0% +place we need a place to to start +testing so the theory of knowledge so + + align:start position:0% +testing so the theory of knowledge so + + + align:start position:0% +testing so the theory of knowledge so +these four components which are driven + + align:start position:0% +these four components which are driven + + + align:start position:0% +these four components which are driven +by the values of the organization that + + align:start position:0% +by the values of the organization that + + + align:start position:0% +by the values of the organization that +we're looking at right we're going to + + align:start position:0% +we're looking at right we're going to + + + align:start position:0% +we're looking at right we're going to +leverage those along with something we + + align:start position:0% +leverage those along with something we + + + align:start position:0% +leverage those along with something we +call subject matter expertise so + + align:start position:0% +call subject matter expertise so + + + align:start position:0% +call subject matter expertise so +Florence and I were just talking about + + align:start position:0% +Florence and I were just talking about + + + align:start position:0% +Florence and I were just talking about +this so so important it's really + + align:start position:0% +this so so important it's really + + + align:start position:0% +this so so important it's really +important to have somebody who can think + + align:start position:0% +important to have somebody who can think + + + align:start position:0% +important to have somebody who can think +from an improvement perspective who can + + align:start position:0% +from an improvement perspective who can + + + align:start position:0% +from an improvement perspective who can +leverage the system of profound + + align:start position:0% +leverage the system of profound + + + align:start position:0% +leverage the system of profound +knowledge but we also need somebody + + align:start position:0% +knowledge but we also need somebody + + + align:start position:0% +knowledge but we also need somebody +who's a subject matter expert right if + + align:start position:0% +who's a subject matter expert right if + + + align:start position:0% +who's a subject matter expert right if +I'm going into Ghana and I want to help + + align:start position:0% +I'm going into Ghana and I want to help + + + align:start position:0% +I'm going into Ghana and I want to help +uh the country of Ghana to reduce under + + align:start position:0% +uh the country of Ghana to reduce under + + + align:start position:0% +uh the country of Ghana to reduce under +five mortality then I need to be working + + align:start position:0% +five mortality then I need to be working + + + align:start position:0% +five mortality then I need to be working +with some people who know about under + + align:start position:0% +with some people who know about under + + + align:start position:0% +with some people who know about under +five mortality I need to be working with + + align:start position:0% +five mortality I need to be working with + + + align:start position:0% +five mortality I need to be working with +some real experts in that environment + + align:start position:0% +some real experts in that environment + + + align:start position:0% +some real experts in that environment +clinicians nurses doctors counselors + + align:start position:0% +clinicians nurses doctors counselors + + + align:start position:0% +clinicians nurses doctors counselors +people who are working with communities + + align:start position:0% +people who are working with communities + + + align:start position:0% +people who are working with communities +who understand the context and + + align:start position:0% +who understand the context and + + + align:start position:0% +who understand the context and +understand the culture where I'm working + + align:start position:0% +understand the culture where I'm working + + + align:start position:0% +understand the culture where I'm working +right and I need to combine that with + + align:start position:0% +right and I need to combine that with + + + align:start position:0% +right and I need to combine that with +profound knowledge with this ability to + + align:start position:0% +profound knowledge with this ability to + + + align:start position:0% +profound knowledge with this ability to +look at Psychology to appreciate the + + align:start position:0% +look at Psychology to appreciate the + + + align:start position:0% +look at Psychology to appreciate the +system to articulate what I believe and + + align:start position:0% +system to articulate what I believe and + + + align:start position:0% +system to articulate what I believe and +to understand performance right if I + + align:start position:0% +to understand performance right if I + + + align:start position:0% +to understand performance right if I +want to achieve Improvement so it's + + align:start position:0% +want to achieve Improvement so it's + + + align:start position:0% +want to achieve Improvement so it's +where you those two things come together + + align:start position:0% +where you those two things come together + + + align:start position:0% +where you those two things come together +that we can actually take quality + + align:start position:0% +that we can actually take quality + + + align:start position:0% +that we can actually take quality +improvement forward right + + align:start position:0% +improvement forward right + + + align:start position:0% +improvement forward right +unfortunately most of us in our formal + + align:start position:0% +unfortunately most of us in our formal + + + align:start position:0% +unfortunately most of us in our formal +education we just learn this we learn + + align:start position:0% +education we just learn this we learn + + + align:start position:0% +education we just learn this we learn +subject matter knowledge right we go + + align:start position:0% +subject matter knowledge right we go + + + align:start position:0% +subject matter knowledge right we go +through our formal education becoming + + align:start position:0% +through our formal education becoming + + + align:start position:0% +through our formal education becoming +ever more expert at a particular thing + + align:start position:0% +ever more expert at a particular thing + + + align:start position:0% +ever more expert at a particular thing +right so Florence you told me you're a + + align:start position:0% +right so Florence you told me you're a + + + align:start position:0% +right so Florence you told me you're a +physician right what type of + + align:start position:0% +physician right what type of + + + align:start position:0% +physician right what type of +gynecologist right + + align:start position:0% +gynecologist right + + + align:start position:0% +gynecologist right +Leo also a physician ICU right would you + + align:start position:0% +Leo also a physician ICU right would you + + + align:start position:0% +Leo also a physician ICU right would you +feel real competent delivering + + align:start position:0% +feel real competent delivering + + + align:start position:0% +feel real competent delivering +gynecological + + align:start position:0% +gynecological + + + align:start position:0% +gynecological +Services how about vice versa we think + + align:start position:0% +Services how about vice versa we think + + + align:start position:0% +Services how about vice versa we think +we can do anything yeah right + + align:start position:0% +we can do anything yeah right + + + align:start position:0% +we can do anything yeah right +the idea there is medicine is especially + + align:start position:0% +the idea there is medicine is especially + + + align:start position:0% +the idea there is medicine is especially +prone to this specialization right we're + + align:start position:0% +prone to this specialization right we're + + + align:start position:0% +prone to this specialization right we're +constantly learning more and more + + align:start position:0% +constantly learning more and more + + + align:start position:0% +constantly learning more and more +information getting more and more + + align:start position:0% +information getting more and more + + + align:start position:0% +information getting more and more +specific about what we can do and + + align:start position:0% +specific about what we can do and + + + align:start position:0% +specific about what we can do and +becoming the best at that but that comes + + align:start position:0% +becoming the best at that but that comes + + + align:start position:0% +becoming the best at that but that comes +at a cost it comes at a cost of not + + align:start position:0% +at a cost it comes at a cost of not + + + align:start position:0% +at a cost it comes at a cost of not +understanding the culture the motivation + + align:start position:0% +understanding the culture the motivation + + + align:start position:0% +understanding the culture the motivation +the performance without be without the + + align:start position:0% +the performance without be without the + + + align:start position:0% +the performance without be without the +ability to see the big picture of what's + + align:start position:0% +ability to see the big picture of what's + + + align:start position:0% +ability to see the big picture of what's +going on for the Whole Health System + + align:start position:0% +going on for the Whole Health System + + + align:start position:0% +going on for the Whole Health System +right so bringing those two things + + align:start position:0% +right so bringing those two things + + + align:start position:0% +right so bringing those two things +together is critically important + + align:start position:0% +together is critically important + + + align:start position:0% +together is critically important +does that make sense to + + align:start position:0% +does that make sense to + + + align:start position:0% +does that make sense to +folks I get so scared when it's such a + + align:start position:0% +folks I get so scared when it's such a + + + align:start position:0% +folks I get so scared when it's such a +silent + + align:start position:0% +silent + + + align:start position:0% +silent +audience any questions on this so + + align:start position:0% +audience any questions on this so + + + align:start position:0% +audience any questions on this so +far all + + align:start position:0% +far all + + + align:start position:0% +far all +right okay so here's what I want you to + + align:start position:0% +right okay so here's what I want you to + + + align:start position:0% +right okay so here's what I want you to +do I know a lot of you have computers so + + align:start position:0% +do I know a lot of you have computers so + + + align:start position:0% +do I know a lot of you have computers so +maybe bring up a spreadsheet or one note + + align:start position:0% +maybe bring up a spreadsheet or one note + + + align:start position:0% +maybe bring up a spreadsheet or one note +Word document something like that do it + + align:start position:0% +Word document something like that do it + + + align:start position:0% +Word document something like that do it +in your head for those who have paper + + align:start position:0% +in your head for those who have paper + + + align:start position:0% +in your head for those who have paper +get out a sheet of paper and a pen okay + + align:start position:0% +get out a sheet of paper and a pen okay + + + align:start position:0% +get out a sheet of paper and a pen okay +here's what I want you to do okay I want + + align:start position:0% +here's what I want you to do okay I want + + + align:start position:0% +here's what I want you to do okay I want +you to choose a number between three and + + align:start position:0% +you to choose a number between three and + + + align:start position:0% +you to choose a number between three and +nine write that down 3 4 5 six 7 8 n + + align:start position:0% +nine write that down 3 4 5 six 7 8 n + + + align:start position:0% +nine write that down 3 4 5 six 7 8 n +okay you have a + + align:start position:0% +okay you have a + + + align:start position:0% +okay you have a +number yes okay good yeah there we go + + align:start position:0% +number yes okay good yeah there we go + + + align:start position:0% +number yes okay good yeah there we go +all right I like Peter all right Next + + align:start position:0% +all right I like Peter all right Next + + + align:start position:0% +all right I like Peter all right Next +Step I want you to multiply your number + + align:start position:0% +Step I want you to multiply your number + + + align:start position:0% +Step I want you to multiply your number +by + + align:start position:0% +by + + + align:start position:0% +by +nine + + align:start position:0% + + + + align:start position:0% + +okay you got that so if you had three + + align:start position:0% +okay you got that so if you had three + + + align:start position:0% +okay you got that so if you had three +your new number is + + align:start position:0% +your new number is + + + align:start position:0% +your new number is +what on the spot 3 * + + align:start position:0% +what on the spot 3 * + + + align:start position:0% +what on the spot 3 * +9 27 good job I'm with Lao I need the + + align:start position:0% +9 27 good job I'm with Lao I need the + + + align:start position:0% +9 27 good job I'm with Lao I need the +calculator all + + align:start position:0% +calculator all + + + align:start position:0% +calculator all +right I want you to add 12 to this new + + align:start position:0% +right I want you to add 12 to this new + + + align:start position:0% +right I want you to add 12 to this new +number + + align:start position:0% + + + + align:start position:0% + +okay got it fast right all right okay + + align:start position:0% +okay got it fast right all right okay + + + align:start position:0% +okay got it fast right all right okay +everybody have a two-digit number just + + align:start position:0% +everybody have a two-digit number just + + + align:start position:0% +everybody have a two-digit number just +real quick if you ended up with + + align:start position:0% +real quick if you ended up with + + + align:start position:0% +real quick if you ended up with +something over a 100 under 10 we're in + + align:start position:0% +something over a 100 under 10 we're in + + + align:start position:0% +something over a 100 under 10 we're in +trouble here just want to make sure okay + + align:start position:0% +trouble here just want to make sure okay + + + align:start position:0% +trouble here just want to make sure okay +I want you to take those two digits and + + align:start position:0% +I want you to take those two digits and + + + align:start position:0% +I want you to take those two digits and +add them together so if my number was 18 + + align:start position:0% +add them together so if my number was 18 + + + align:start position:0% +add them together so if my number was 18 +I would take 1 + 8 that would equal + + align:start position:0% +I would take 1 + 8 that would equal + + + align:start position:0% +I would take 1 + 8 that would equal +9 you got that all right math is almost + + align:start position:0% +9 you got that all right math is almost + + + align:start position:0% +9 you got that all right math is almost +done for the day I know you guys weren't + + align:start position:0% +done for the day I know you guys weren't + + + align:start position:0% +done for the day I know you guys weren't +expecting that this morning early in the + + align:start position:0% +expecting that this morning early in the + + + align:start position:0% +expecting that this morning early in the +morning all right divide that number by + + align:start position:0% + + + + align:start position:0% + +three should have a one-digit number + + align:start position:0% +three should have a one-digit number + + + align:start position:0% +three should have a one-digit number +everybody got a one-digit + + align:start position:0% +everybody got a one-digit + + + align:start position:0% +everybody got a one-digit +number all right now whatever your + + align:start position:0% +number all right now whatever your + + + align:start position:0% +number all right now whatever your +number is I want you to convert it to a + + align:start position:0% +number is I want you to convert it to a + + + align:start position:0% +number is I want you to convert it to a +letter so if your number is one you now + + align:start position:0% +letter so if your number is one you now + + + align:start position:0% +letter so if your number is one you now +have the letter A if your number is two + + align:start position:0% +have the letter A if your number is two + + + align:start position:0% +have the letter A if your number is two +you have the letter b and and so on have + + align:start position:0% +you have the letter b and and so on have + + + align:start position:0% +you have the letter b and and so on have +you got your + + align:start position:0% +you got your + + + align:start position:0% +you got your +letter + + align:start position:0% + + + + align:start position:0% + +okay I want you to write down the name + + align:start position:0% +okay I want you to write down the name + + + align:start position:0% +okay I want you to write down the name +of a country that begins with your + + align:start position:0% +of a country that begins with your + + + align:start position:0% +of a country that begins with your +letter okay + + align:start position:0% + + + + align:start position:0% + +all + + align:start position:0% +all + + + align:start position:0% +all +right Next Step whatever your letter was + + align:start position:0% +right Next Step whatever your letter was + + + align:start position:0% +right Next Step whatever your letter was +I want you to take the next letter in + + align:start position:0% +I want you to take the next letter in + + + align:start position:0% +I want you to take the next letter in +the alphabet so if my letter was a my + + align:start position:0% +the alphabet so if my letter was a my + + + align:start position:0% +the alphabet so if my letter was a my +new letter is B okay let's take that + + align:start position:0% +new letter is B okay let's take that + + + align:start position:0% +new letter is B okay let's take that +letter I want you to write down the name + + align:start position:0% +letter I want you to write down the name + + + align:start position:0% +letter I want you to write down the name +of an animal that begins with that + + align:start position:0% +of an animal that begins with that + + + align:start position:0% +of an animal that begins with that +letter okay so it can't be a bird or an + + align:start position:0% +letter okay so it can't be a bird or an + + + align:start position:0% +letter okay so it can't be a bird or an +insect or a fish I want like a land + + align:start position:0% +insect or a fish I want like a land + + + align:start position:0% +insect or a fish I want like a land +dwelling mammal + + align:start position:0% + + + + align:start position:0% + +got + + align:start position:0% +got + + + align:start position:0% +got +it all right last step here I want you + + align:start position:0% +it all right last step here I want you + + + align:start position:0% +it all right last step here I want you +to write down the color of your + + align:start position:0% + + + + align:start position:0% + +animal the color of the + + align:start position:0% +animal the color of the + + + align:start position:0% +animal the color of the +animal + + align:start position:0% + + + + align:start position:0% + +okay all right yall with + + align:start position:0% +okay all right yall with + + + align:start position:0% +okay all right yall with +me there you go + + align:start position:0% +me there you go + + + align:start position:0% +me there you go +okay any + + align:start position:0% +okay any + + + align:start position:0% +okay any +what country did you have Denmark + + align:start position:0% +what country did you have Denmark + + + align:start position:0% +what country did you have Denmark +Denmark what animal did you + + align:start position:0% +Denmark what animal did you + + + align:start position:0% +Denmark what animal did you +have what color is an + + align:start position:0% +have what color is an + + + align:start position:0% +have what color is an +elephant how many people had a gray + + align:start position:0% +elephant how many people had a gray + + + align:start position:0% +elephant how many people had a gray +elephant in + + align:start position:0% +elephant in + + + align:start position:0% +elephant in +Denmark wow wow that's + + align:start position:0% +Denmark wow wow that's + + + align:start position:0% +Denmark wow wow that's +incredible now Annie one quick question + + align:start position:0% +incredible now Annie one quick question + + + align:start position:0% +incredible now Annie one quick question +here what number did you start + + align:start position:0% +here what number did you start + + + align:start position:0% +here what number did you start +with six did you all start with six you + + align:start position:0% +with six did you all start with six you + + + align:start position:0% +with six did you all start with six you +started with six but no what what what + + align:start position:0% +started with six but no what what what + + + align:start position:0% +started with six but no what what what +was seven five eight + + align:start position:0% +was seven five eight + + + align:start position:0% +was seven five eight +right wow amazing so there's some + + align:start position:0% +right wow amazing so there's some + + + align:start position:0% +right wow amazing so there's some +there's some variation here there's a + + align:start position:0% +there's some variation here there's a + + + align:start position:0% +there's some variation here there's a +few people who might have gotten + + align:start position:0% +few people who might have gotten + + + align:start position:0% +few people who might have gotten +something + + align:start position:0% +something + + + align:start position:0% +something +different but what + + align:start position:0% +different but what + + + align:start position:0% +different but what +happened you had some free choice here + + align:start position:0% +happened you had some free choice here + + + align:start position:0% +happened you had some free choice here +you could have chose any number right + + align:start position:0% +you could have chose any number right + + + align:start position:0% +you could have chose any number right +you made the + + align:start position:0% +you made the + + + align:start position:0% +you made the +decision what happened was the process + + align:start position:0% +decision what happened was the process + + + align:start position:0% +decision what happened was the process +took over right we put you into a + + align:start position:0% +took over right we put you into a + + + align:start position:0% +took over right we put you into a +process and we started the dec the the + + align:start position:0% +process and we started the dec the the + + + align:start position:0% +process and we started the dec the the +process started to make decisions about + + align:start position:0% +process started to make decisions about + + + align:start position:0% +process started to make decisions about +what your outcome was going to be right + + align:start position:0% +what your outcome was going to be right + + + align:start position:0% +what your outcome was going to be right +now in any given room about nine out of + + align:start position:0% +now in any given room about nine out of + + + align:start position:0% +now in any given room about nine out of +10 people are going to get a gray + + align:start position:0% +10 people are going to get a gray + + + align:start position:0% +10 people are going to get a gray +elephant in + + align:start position:0% +elephant in + + + align:start position:0% +elephant in +Denmark you get a few people who are + + align:start position:0% +Denmark you get a few people who are + + + align:start position:0% +Denmark you get a few people who are +going to get a Eland in the Dominican + + align:start position:0% +going to get a Eland in the Dominican + + + align:start position:0% +going to get a Eland in the Dominican +Republic or something like that right + + align:start position:0% +Republic or something like that right + + + align:start position:0% +Republic or something like that right +but that's pretty rare right and this is + + align:start position:0% +but that's pretty rare right and this is + + + align:start position:0% +but that's pretty rare right and this is +an important lesson that Deming gave us + + align:start position:0% +an important lesson that Deming gave us + + + align:start position:0% +an important lesson that Deming gave us +about appreciation of systems okay so + + align:start position:0% +about appreciation of systems okay so + + + align:start position:0% +about appreciation of systems okay so +Deming argued from a statistical + + align:start position:0% +Deming argued from a statistical + + + align:start position:0% +Deming argued from a statistical +perspective that about 95% of all the + + align:start position:0% +perspective that about 95% of all the + + + align:start position:0% +perspective that about 95% of all the +variation we see in stable performance + + align:start position:0% +variation we see in stable performance + + + align:start position:0% +variation we see in stable performance +of of + + align:start position:0% +of of + + + align:start position:0% +of of +systems is the responsibility of the + + align:start position:0% +systems is the responsibility of the + + + align:start position:0% +systems is the responsibility of the +system itself not of the individual + + align:start position:0% +system itself not of the individual + + + align:start position:0% +system itself not of the individual +workers right I know it's only about + + align:start position:0% +workers right I know it's only about + + + align:start position:0% +workers right I know it's only about +5% so a lot of times we hear + + align:start position:0% +5% so a lot of times we hear + + + align:start position:0% +5% so a lot of times we hear +admonishments you know if people just + + align:start position:0% +admonishments you know if people just + + + align:start position:0% +admonishments you know if people just +worked harder you know maybe if we paid + + align:start position:0% +worked harder you know maybe if we paid + + + align:start position:0% +worked harder you know maybe if we paid +them a little + + align:start position:0% +them a little + + + align:start position:0% +them a little +more right maybe if we punished them + + align:start position:0% +more right maybe if we punished them + + + align:start position:0% +more right maybe if we punished them +then we'd really get something done + + align:start position:0% +then we'd really get something done + + + align:start position:0% +then we'd really get something done +right the reality is that's not the case + + align:start position:0% +right the reality is that's not the case + + + align:start position:0% +right the reality is that's not the case +it's a system that controls the outcome + + align:start position:0% +it's a system that controls the outcome + + + align:start position:0% +it's a system that controls the outcome +so if I'm in a resource constrained + + align:start position:0% +so if I'm in a resource constrained + + + align:start position:0% +so if I'm in a resource constrained +environment and I see really high + + align:start position:0% +environment and I see really high + + + align:start position:0% +environment and I see really high +mortality rates let's say I'm in Ghana + + align:start position:0% +mortality rates let's say I'm in Ghana + + + align:start position:0% +mortality rates let's say I'm in Ghana +and I have you know 80 uh uh deaths in + + align:start position:0% +and I have you know 80 uh uh deaths in + + + align:start position:0% +and I have you know 80 uh uh deaths in +children under the age of five for every + + align:start position:0% +children under the age of five for every + + + align:start position:0% +children under the age of five for every +thousand live births right that is a + + align:start position:0% +thousand live births right that is a + + + align:start position:0% +thousand live births right that is a +product of the system that I'm in it's + + align:start position:0% +product of the system that I'm in it's + + + align:start position:0% +product of the system that I'm in it's +no one person's fault it's not laziness + + align:start position:0% +no one person's fault it's not laziness + + + align:start position:0% +no one person's fault it's not laziness +on the part of the workers it is the + + align:start position:0% +on the part of the workers it is the + + + align:start position:0% +on the part of the workers it is the +system itself right Leo introduced us to + + align:start position:0% +system itself right Leo introduced us to + + + align:start position:0% +system itself right Leo introduced us to +the concept of every system being + + align:start position:0% +the concept of every system being + + + align:start position:0% +the concept of every system being +perfectly designed to achieve the + + align:start position:0% +perfectly designed to achieve the + + + align:start position:0% +perfectly designed to achieve the +results it gets that's what he's talking + + align:start position:0% +results it gets that's what he's talking + + + align:start position:0% +results it gets that's what he's talking +about right there okay that's what he's + + align:start position:0% +about right there okay that's what he's + + + align:start position:0% +about right there okay that's what he's +talking about right there does that make + + align:start position:0% +talking about right there does that make + + + align:start position:0% +talking about right there does that make +sense to folks this is an incredibly + + align:start position:0% +sense to folks this is an incredibly + + + align:start position:0% +sense to folks this is an incredibly +important concept when you start to + + align:start position:0% +important concept when you start to + + + align:start position:0% +important concept when you start to +think about quality improvement right + + align:start position:0% +think about quality improvement right + + + align:start position:0% +think about quality improvement right +this quality improvement needs to be + + align:start position:0% +this quality improvement needs to be + + + align:start position:0% +this quality improvement needs to be +leveraged on the system not on the + + align:start position:0% +leveraged on the system not on the + + + align:start position:0% +leveraged on the system not on the +individuals so let's let's do another + + align:start position:0% +individuals so let's let's do another + + + align:start position:0% +individuals so let's let's do another +example Leo come come come + + align:start position:0% + + + + align:start position:0% + +here you're a pretty healthy guy + + align:start position:0% +here you're a pretty healthy guy + + + align:start position:0% +here you're a pretty healthy guy +right exercise frequently all right Le I + + align:start position:0% +right exercise frequently all right Le I + + + align:start position:0% +right exercise frequently all right Le I +want you to jump up and touch the + + align:start position:0% +want you to jump up and touch the + + + align:start position:0% +want you to jump up and touch the +ceiling + + align:start position:0% +ceiling + + + align:start position:0% +ceiling +can you do that for me they can't see it + + align:start position:0% +can you do that for me they can't see it + + + align:start position:0% +can you do that for me they can't see it +though no go ahead just just give it a + + align:start position:0% +though no go ahead just just give it a + + + align:start position:0% +though no go ahead just just give it a +jump give it a shot + + align:start position:0% +jump give it a shot + + + align:start position:0% +jump give it a shot +seriously all right that wasn't too good + + align:start position:0% +seriously all right that wasn't too good + + + align:start position:0% +seriously all right that wasn't too good +I don't think he's properly I I I don't + + align:start position:0% +I don't think he's properly I I I don't + + + align:start position:0% +I don't think he's properly I I I don't +think he's properly motivated Leo here's + + align:start position:0% +think he's properly motivated Leo here's + + + align:start position:0% +think he's properly motivated Leo here's +some + + align:start position:0% +some + + + align:start position:0% +some +money if you could touch a ceiling you + + align:start position:0% +money if you could touch a ceiling you + + + align:start position:0% +money if you could touch a ceiling you +can have all that money you think you + + align:start position:0% +can have all that money you think you + + + align:start position:0% +can have all that money you think you +could do it oh it's some the + + align:start position:0% +could do it oh it's some the + + + align:start position:0% +could do it oh it's some the +Trap right it's a system right we talk + + align:start position:0% +Trap right it's a system right we talk + + + align:start position:0% +Trap right it's a system right we talk +about pay for performance you can't + + align:start position:0% +about pay for performance you can't + + + align:start position:0% +about pay for performance you can't +really pay for performance when a system + + align:start position:0% +really pay for performance when a system + + + align:start position:0% +really pay for performance when a system +is controlling the outcome right there's + + align:start position:0% +is controlling the outcome right there's + + + align:start position:0% +is controlling the outcome right there's +no way he's ever going to touch the + + align:start position:0% +no way he's ever going to touch the + + + align:start position:0% +no way he's ever going to touch the +ceiling not not just from a standing + + align:start position:0% +ceiling not not just from a standing + + + align:start position:0% +ceiling not not just from a standing +jump so it's incredibly important to + + align:start position:0% +jump so it's incredibly important to + + + align:start position:0% +jump so it's incredibly important to +have that systems view what I want to + + align:start position:0% +have that systems view what I want to + + + align:start position:0% +have that systems view what I want to +introduce you to is a tool that Demi + + align:start position:0% +introduce you to is a tool that Demi + + + align:start position:0% +introduce you to is a tool that Demi +gave us for starting to develop that now + + align:start position:0% +gave us for starting to develop that now + + + align:start position:0% +gave us for starting to develop that now +we're going to look at it conceptually + + align:start position:0% +we're going to look at it conceptually + + + align:start position:0% +we're going to look at it conceptually +but you can do it very very specifically + + align:start position:0% +but you can do it very very specifically + + + align:start position:0% +but you can do it very very specifically +for any system that you work in okay so + + align:start position:0% +for any system that you work in okay so + + + align:start position:0% +for any system that you work in okay so +what is a system it's a collection of + + align:start position:0% +what is a system it's a collection of + + + align:start position:0% +what is a system it's a collection of +processes working together towards a + + align:start position:0% +processes working together towards a + + + align:start position:0% +processes working together towards a +defined output that's that's how we + + align:start position:0% +defined output that's that's how we + + + align:start position:0% +defined output that's that's how we +would Define that right + + align:start position:0% +would Define that right + + + align:start position:0% +would Define that right +so and Demi would argue it's where you + + align:start position:0% +so and Demi would argue it's where you + + + align:start position:0% +so and Demi would argue it's where you +draw the circle right it could be a + + align:start position:0% +draw the circle right it could be a + + + align:start position:0% +draw the circle right it could be a +single process it could be uh say + + align:start position:0% +single process it could be uh say + + + align:start position:0% +single process it could be uh say +something like antinal care which is a + + align:start position:0% +something like antinal care which is a + + + align:start position:0% +something like antinal care which is a +single process or we could take into + + align:start position:0% +single process or we could take into + + + align:start position:0% +single process or we could take into +account labor and delivery as well even + + align:start position:0% +account labor and delivery as well even + + + align:start position:0% +account labor and delivery as well even +postnatal care now we're grouping a set + + align:start position:0% +postnatal care now we're grouping a set + + + align:start position:0% +postnatal care now we're grouping a set +of processes together that are working + + align:start position:0% +of processes together that are working + + + align:start position:0% +of processes together that are working +towards a defined output which might be + + align:start position:0% +towards a defined output which might be + + + align:start position:0% +towards a defined output which might be +a healthy child right we might even say + + align:start position:0% +a healthy child right we might even say + + + align:start position:0% +a healthy child right we might even say +it's the Continuum of Care from birth + + align:start position:0% +it's the Continuum of Care from birth + + + align:start position:0% +it's the Continuum of Care from birth +through death so now we're talking about + + align:start position:0% +through death so now we're talking about + + + align:start position:0% +through death so now we're talking about +everything we're talking about uh + + align:start position:0% +everything we're talking about uh + + + align:start position:0% +everything we're talking about uh +chronic disease management we're talking + + align:start position:0% +chronic disease management we're talking + + + align:start position:0% +chronic disease management we're talking +about acute care settings Emergency + + align:start position:0% +about acute care settings Emergency + + + align:start position:0% +about acute care settings Emergency +Settings all that can be put into a + + align:start position:0% +Settings all that can be put into a + + + align:start position:0% +Settings all that can be put into a +system right you get to + + align:start position:0% +system right you get to + + + align:start position:0% +system right you get to +decide the larger you draw the circle + + align:start position:0% +decide the larger you draw the circle + + + align:start position:0% +decide the larger you draw the circle +the more complex the interactions are + + align:start position:0% +the more complex the interactions are + + + align:start position:0% +the more complex the interactions are +going to become and so it's more and + + align:start position:0% +going to become and so it's more and + + + align:start position:0% +going to become and so it's more and +more important to have the ability to + + align:start position:0% +more important to have the ability to + + + align:start position:0% +more important to have the ability to +see what's going on now I think Leo you + + align:start position:0% +see what's going on now I think Leo you + + + align:start position:0% +see what's going on now I think Leo you +you you attributed this quote to Don + + align:start position:0% +you you attributed this quote to Don + + + align:start position:0% +you you attributed this quote to Don +Berwick and I'm I'm attributing it to + + align:start position:0% +Berwick and I'm I'm attributing it to + + + align:start position:0% +Berwick and I'm I'm attributing it to +Paul Balden and they're very good + + align:start position:0% +Paul Balden and they're very good + + + align:start position:0% +Paul Balden and they're very good +friends um and and both of them say that + + align:start position:0% +friends um and and both of them say that + + + align:start position:0% +friends um and and both of them say that +the other person said this so it's + + align:start position:0% +the other person said this so it's + + + align:start position:0% +the other person said this so it's +actually it's quite funny they argue + + align:start position:0% +actually it's quite funny they argue + + + align:start position:0% +actually it's quite funny they argue +about it all the time um so I figured I + + align:start position:0% +about it all the time um so I figured I + + + align:start position:0% +about it all the time um so I figured I +would do the different one since you + + align:start position:0% +would do the different one since you + + + align:start position:0% +would do the different one since you +said it was Don's all right + + align:start position:0% + + + + align:start position:0% + +so what's the best tool for + + align:start position:0% +so what's the best tool for + + + align:start position:0% +so what's the best tool for +understanding systems right there's lots + + align:start position:0% +understanding systems right there's lots + + + align:start position:0% +understanding systems right there's lots +of tools we can use we're going to talk + + align:start position:0% +of tools we can use we're going to talk + + + align:start position:0% +of tools we can use we're going to talk +about two this morning all right but + + align:start position:0% +about two this morning all right but + + + align:start position:0% +about two this morning all right but +it's really important that when you + + align:start position:0% +it's really important that when you + + + align:start position:0% +it's really important that when you +approach a a problem A System's problem + + align:start position:0% +approach a a problem A System's problem + + + align:start position:0% +approach a a problem A System's problem +that you have a perspective of which + + align:start position:0% +that you have a perspective of which + + + align:start position:0% +that you have a perspective of which +tool right has everyone ever heard the + + align:start position:0% +tool right has everyone ever heard the + + + align:start position:0% +tool right has everyone ever heard the +saying you when all you have is a hammer + + align:start position:0% +saying you when all you have is a hammer + + + align:start position:0% +saying you when all you have is a hammer +the whole world looks like a nail + + align:start position:0% +the whole world looks like a nail + + + align:start position:0% +the whole world looks like a nail +right so important when you're + + align:start position:0% +right so important when you're + + + align:start position:0% +right so important when you're +approaching A System's problem to + + align:start position:0% +approaching A System's problem to + + + align:start position:0% +approaching A System's problem to +approach it with a series of tools and + + align:start position:0% +approach it with a series of tools and + + + align:start position:0% +approach it with a series of tools and +and and try to choose something that's + + align:start position:0% +and and try to choose something that's + + + align:start position:0% +and and try to choose something that's +going to work + + align:start position:0% +going to work + + + align:start position:0% +going to work +appropriately okay so what I'm going to + + align:start position:0% +appropriately okay so what I'm going to + + + align:start position:0% +appropriately okay so what I'm going to +introduce today is is deming's linkage + + align:start position:0% +introduce today is is deming's linkage + + + align:start position:0% +introduce today is is deming's linkage +of process this is adapted from + + align:start position:0% +of process this is adapted from + + + align:start position:0% +of process this is adapted from +Associates and process Improvement a + + align:start position:0% +Associates and process Improvement a + + + align:start position:0% +Associates and process Improvement a +group of his students who have taken his + + align:start position:0% +group of his students who have taken his + + + align:start position:0% +group of his students who have taken his +work further um and linkage a process is + + align:start position:0% +work further um and linkage a process is + + + align:start position:0% +work further um and linkage a process is +a is a way of viewing all of the work + + align:start position:0% +a is a way of viewing all of the work + + + align:start position:0% +a is a way of viewing all of the work +that is happening within a system Demi + + align:start position:0% +that is happening within a system Demi + + + align:start position:0% +that is happening within a system Demi +argued he he said one of his famous + + align:start position:0% +argued he he said one of his famous + + + align:start position:0% +argued he he said one of his famous +quotes was all work is a process or all + + align:start position:0% +quotes was all work is a process or all + + + align:start position:0% +quotes was all work is a process or all +processes as work one of the + + align:start position:0% +processes as work one of the + + + align:start position:0% +processes as work one of the +two he said a an organization starts + + align:start position:0% +two he said a an organization starts + + + align:start position:0% +two he said a an organization starts +with a purpose okay a system starts with + + align:start position:0% +with a purpose okay a system starts with + + + align:start position:0% +with a purpose okay a system starts with +a purpose and we need to Define what + + align:start position:0% +a purpose and we need to Define what + + + align:start position:0% +a purpose and we need to Define what +that is what is that particular thing + + align:start position:0% +that is what is that particular thing + + + align:start position:0% +that is what is that particular thing +why do we exist as an organization okay + + align:start position:0% +why do we exist as an organization okay + + + align:start position:0% +why do we exist as an organization okay +do we have a sense of + + align:start position:0% +do we have a sense of + + + align:start position:0% +do we have a sense of +that that's going to control what our + + align:start position:0% +that that's going to control what our + + + align:start position:0% +that that's going to control what our +outcome will be what our sort of uh what + + align:start position:0% +outcome will be what our sort of uh what + + + align:start position:0% +outcome will be what our sort of uh what +it is we're going to produce for our + + align:start position:0% +it is we're going to produce for our + + + align:start position:0% +it is we're going to produce for our +clients so uh that's that's important + + align:start position:0% +clients so uh that's that's important + + + align:start position:0% +clients so uh that's that's important +from a health perspective that might be + + align:start position:0% + + + + align:start position:0% + +what say that again improved health + + align:start position:0% +what say that again improved health + + + align:start position:0% +what say that again improved health +status yeah improved health status right + + align:start position:0% +status yeah improved health status right + + + align:start position:0% +status yeah improved health status right +right we ever heard that health for all + + align:start position:0% +right we ever heard that health for all + + + align:start position:0% +right we ever heard that health for all +things like that sort of sort of vague + + align:start position:0% +things like that sort of sort of vague + + + align:start position:0% +things like that sort of sort of vague +things right or it could be something + + align:start position:0% +things right or it could be something + + + align:start position:0% +things right or it could be something +very specific it could be a particular + + align:start position:0% +very specific it could be a particular + + + align:start position:0% +very specific it could be a particular +outcome from say a surgery okay so + + align:start position:0% +outcome from say a surgery okay so + + + align:start position:0% +outcome from say a surgery okay so +whatever it is we want to be very clear + + align:start position:0% +whatever it is we want to be very clear + + + align:start position:0% +whatever it is we want to be very clear +about what it is that our + + align:start position:0% +about what it is that our + + + align:start position:0% +about what it is that our +outcome the outcome that we want to + + align:start position:0% +outcome the outcome that we want to + + + align:start position:0% +outcome the outcome that we want to +deliver now Deming said that there is + + align:start position:0% +deliver now Deming said that there is + + + align:start position:0% +deliver now Deming said that there is +work that we do that is focused on + + align:start position:0% +work that we do that is focused on + + + align:start position:0% +work that we do that is focused on +producing that outcome so let's take uh + + align:start position:0% +producing that outcome so let's take uh + + + align:start position:0% +producing that outcome so let's take uh +uh maternal mortality I know that's a an + + align:start position:0% +uh maternal mortality I know that's a an + + + align:start position:0% +uh maternal mortality I know that's a an +issue for a lot of folks in here and + + align:start position:0% +issue for a lot of folks in here and + + + align:start position:0% +issue for a lot of folks in here and +that are people are interested in in ch + + align:start position:0% +that are people are interested in in ch + + + align:start position:0% +that are people are interested in in ch +Early Childhood mortality it's something + + align:start position:0% +Early Childhood mortality it's something + + + align:start position:0% +Early Childhood mortality it's something +that's I'm interested in okay uh there + + align:start position:0% +that's I'm interested in okay uh there + + + align:start position:0% +that's I'm interested in okay uh there +are things that we do we provide antinal + + align:start position:0% +are things that we do we provide antinal + + + align:start position:0% +are things that we do we provide antinal +care we want to get people in early we + + align:start position:0% +care we want to get people in early we + + + align:start position:0% +care we want to get people in early we +want to get pregnant women in early and + + align:start position:0% +want to get pregnant women in early and + + + align:start position:0% +want to get pregnant women in early and +identify them as as being pregnant and + + align:start position:0% +identify them as as being pregnant and + + + align:start position:0% +identify them as as being pregnant and +then start delivering a set of Services + + align:start position:0% +then start delivering a set of Services + + + align:start position:0% +then start delivering a set of Services +immunizations care monitoring their + + align:start position:0% +immunizations care monitoring their + + + align:start position:0% +immunizations care monitoring their +pregnancy uh right there's a certain + + align:start position:0% +pregnancy uh right there's a certain + + + align:start position:0% +pregnancy uh right there's a certain +level of patient care that's taking + + align:start position:0% +level of patient care that's taking + + + align:start position:0% +level of patient care that's taking +place Deming called this the Mainstay + + align:start position:0% +place Deming called this the Mainstay + + + align:start position:0% +place Deming called this the Mainstay +processes okay these are things that you + + align:start position:0% +processes okay these are things that you + + + align:start position:0% +processes okay these are things that you +are doing to get the outcome that you + + align:start position:0% +are doing to get the outcome that you + + + align:start position:0% +are doing to get the outcome that you +want right if it were surgical care it + + align:start position:0% +want right if it were surgical care it + + + align:start position:0% +want right if it were surgical care it +would be doing the surgery going into + + align:start position:0% +would be doing the surgery going into + + + align:start position:0% +would be doing the surgery going into +the theater with the patient surgical + + align:start position:0% +the theater with the patient surgical + + + align:start position:0% +the theater with the patient surgical +team delivering the surgery right does + + align:start position:0% +team delivering the surgery right does + + + align:start position:0% +team delivering the surgery right does +that make + + align:start position:0% +that make + + + align:start position:0% +that make +sense no yes okay so we could map each + + align:start position:0% +sense no yes okay so we could map each + + + align:start position:0% +sense no yes okay so we could map each +one of those + + align:start position:0% +one of those + + + align:start position:0% +one of those +processes right there's a process for + + align:start position:0% +processes right there's a process for + + + align:start position:0% +processes right there's a process for +registering the patient there's a + + align:start position:0% +registering the patient there's a + + + align:start position:0% +registering the patient there's a +process for their first visit there's a + + align:start position:0% +process for their first visit there's a + + + align:start position:0% +process for their first visit there's a +separate process with a whole bunch of + + align:start position:0% +separate process with a whole bunch of + + + align:start position:0% +separate process with a whole bunch of +steps for their second visit third visit + + align:start position:0% +steps for their second visit third visit + + + align:start position:0% +steps for their second visit third visit +Etc okay and all of that is the main + + align:start position:0% +Etc okay and all of that is the main + + + align:start position:0% +Etc okay and all of that is the main +stay leading to a particular + + align:start position:0% +stay leading to a particular + + + align:start position:0% +stay leading to a particular +outcome in order to do that work we need + + align:start position:0% +outcome in order to do that work we need + + + align:start position:0% +outcome in order to do that work we need +supplies right we need an environment to + + align:start position:0% +supplies right we need an environment to + + + align:start position:0% +supplies right we need an environment to +work in we need the people the workers + + align:start position:0% +work in we need the people the workers + + + align:start position:0% +work in we need the people the workers +who can actually do the work right + + align:start position:0% +who can actually do the work right + + + align:start position:0% +who can actually do the work right +there's their education there's the the + + align:start position:0% +there's their education there's the the + + + align:start position:0% +there's their education there's the the +drugs that we need the pharmaceutical + + align:start position:0% +drugs that we need the pharmaceutical + + + align:start position:0% +drugs that we need the pharmaceutical +stuff that we we take advantage of all + + align:start position:0% +stuff that we we take advantage of all + + + align:start position:0% +stuff that we we take advantage of all +of that is going into to our main stay + + align:start position:0% +of that is going into to our main stay + + + align:start position:0% +of that is going into to our main stay +in order to provide care to our patients + + align:start position:0% +in order to provide care to our patients + + + align:start position:0% +in order to provide care to our patients +to get the outcome that we want right + + align:start position:0% +to get the outcome that we want right + + + align:start position:0% +to get the outcome that we want right +and all of that can be articulated as + + align:start position:0% +and all of that can be articulated as + + + align:start position:0% +and all of that can be articulated as +well each one of those processes has a + + align:start position:0% +well each one of those processes has a + + + align:start position:0% +well each one of those processes has a +whole set of steps that we can look at + + align:start position:0% +whole set of steps that we can look at + + + align:start position:0% +whole set of steps that we can look at +does that make sense and one process + + align:start position:0% +does that make sense and one process + + + align:start position:0% +does that make sense and one process +leads to another yeah straightforward + + align:start position:0% +leads to another yeah straightforward + + + align:start position:0% +leads to another yeah straightforward +okay well here's where it gets a little + + align:start position:0% +okay well here's where it gets a little + + + align:start position:0% +okay well here's where it gets a little +more complicated okay now there's some + + align:start position:0% +more complicated okay now there's some + + + align:start position:0% +more complicated okay now there's some +other things that are going on right + + align:start position:0% +other things that are going on right + + + align:start position:0% +other things that are going on right +that have nothing to do with actual + + align:start position:0% +that have nothing to do with actual + + + align:start position:0% +that have nothing to do with actual +patient care right now they're related + + align:start position:0% +patient care right now they're related + + + align:start position:0% +patient care right now they're related +but they're different right they're not + + align:start position:0% +but they're different right they're not + + + align:start position:0% +but they're different right they're not +they are not the business of delivering + + align:start position:0% +they are not the business of delivering + + + align:start position:0% +they are not the business of delivering +the care one of those things is the + + align:start position:0% +the care one of those things is the + + + align:start position:0% +the care one of those things is the +business of monitoring the delivery of + + align:start position:0% +business of monitoring the delivery of + + + align:start position:0% +business of monitoring the delivery of +that care right so we have measurement + + align:start position:0% +that care right so we have measurement + + + align:start position:0% +that care right so we have measurement +and feedback should be a part of a + + align:start position:0% +and feedback should be a part of a + + + align:start position:0% +and feedback should be a part of a +system okay and that's the part that I + + align:start position:0% +system okay and that's the part that I + + + align:start position:0% +system okay and that's the part that I +think we're focusing on very closely uh + + align:start position:0% +think we're focusing on very closely uh + + + align:start position:0% +think we're focusing on very closely uh +uh this semester but how do we get that + + align:start position:0% +uh this semester but how do we get that + + + align:start position:0% +uh this semester but how do we get that +right right and there's sort of two + + align:start position:0% +right right and there's sort of two + + + align:start position:0% +right right and there's sort of two +voices here there's the voice of the + + align:start position:0% +voices here there's the voice of the + + + align:start position:0% +voices here there's the voice of the +customer right which is a work that this + + align:start position:0% +customer right which is a work that this + + + align:start position:0% +customer right which is a work that this +that the customer is telling us about + + align:start position:0% +that the customer is telling us about + + + align:start position:0% +that the customer is telling us about +how well things are going right if we're + + align:start position:0% +how well things are going right if we're + + + align:start position:0% +how well things are going right if we're +providing surgical care and our patients + + align:start position:0% +providing surgical care and our patients + + + align:start position:0% +providing surgical care and our patients +are dying on the table what's the voice + + align:start position:0% +are dying on the table what's the voice + + + align:start position:0% +are dying on the table what's the voice +of the customer telling + + align:start position:0% +of the customer telling + + + align:start position:0% +of the customer telling +us we're not doing too good right + + align:start position:0% +us we're not doing too good right + + + align:start position:0% +us we're not doing too good right +mortality is high that's not good that's + + align:start position:0% +mortality is high that's not good that's + + + align:start position:0% +mortality is high that's not good that's +not what we want right in Ghana where we + + align:start position:0% +not what we want right in Ghana where we + + + align:start position:0% +not what we want right in Ghana where we +have high under five mortality right we + + align:start position:0% +have high under five mortality right we + + + align:start position:0% +have high under five mortality right we +know we're not doing too good the + + align:start position:0% +know we're not doing too good the + + + align:start position:0% +know we're not doing too good the +mortality data is telling us that we + + align:start position:0% +mortality data is telling us that we + + + align:start position:0% +mortality data is telling us that we +need to be doing better okay we also + + align:start position:0% +need to be doing better okay we also + + + align:start position:0% +need to be doing better okay we also +have the voice of the process okay the + + align:start position:0% +have the voice of the process okay the + + + align:start position:0% +have the voice of the process okay the +voice of the system so we can measure + + align:start position:0% +voice of the system so we can measure + + + align:start position:0% +voice of the system so we can measure +our ability to provide care and we do + + align:start position:0% +our ability to provide care and we do + + + align:start position:0% +our ability to provide care and we do +that all the time don't we we look at + + align:start position:0% +that all the time don't we we look at + + + align:start position:0% +that all the time don't we we look at +things like weight times patient volumes + + align:start position:0% +things like weight times patient volumes + + + align:start position:0% +things like weight times patient volumes +throughput we look at patient + + align:start position:0% +throughput we look at patient + + + align:start position:0% +throughput we look at patient +satisfaction which would be on this + + align:start position:0% +satisfaction which would be on this + + + align:start position:0% +satisfaction which would be on this +other side looking backwards okay so we + + align:start position:0% +other side looking backwards okay so we + + + align:start position:0% +other side looking backwards okay so we +have these two things that we're + + align:start position:0% +have these two things that we're + + + align:start position:0% +have these two things that we're +measuring the measure the voice of the + + align:start position:0% +measuring the measure the voice of the + + + align:start position:0% +measuring the measure the voice of the +system and the voice of the + + align:start position:0% +system and the voice of the + + + align:start position:0% +system and the voice of the +customer another part of a good system + + align:start position:0% + + + + align:start position:0% + +yeah or how toch + + align:start position:0% + + + + align:start position:0% + +ours definitely definitely so I think + + align:start position:0% +ours definitely definitely so I think + + + align:start position:0% +ours definitely definitely so I think +what you're describing is the + + align:start position:0% +what you're describing is the + + + align:start position:0% +what you're describing is the +interaction between understanding + + align:start position:0% +interaction between understanding + + + align:start position:0% +interaction between understanding +variation in our system and what we + + align:start position:0% +variation in our system and what we + + + align:start position:0% +variation in our system and what we +believe about why things are the way + + align:start position:0% +believe about why things are the way + + + align:start position:0% +believe about why things are the way +that they are so we're going to we're + + align:start position:0% +that they are so we're going to we're + + + align:start position:0% +that they are so we're going to we're +going to try and articulate that we're + + align:start position:0% +going to try and articulate that we're + + + align:start position:0% +going to try and articulate that we're +going to write it down somewhere maybe + + align:start position:0% +going to write it down somewhere maybe + + + align:start position:0% +going to write it down somewhere maybe +in a project Charter okay and we're + + align:start position:0% +in a project Charter okay and we're + + + align:start position:0% +in a project Charter okay and we're +going to lay out a set of measures that + + align:start position:0% +going to lay out a set of measures that + + + align:start position:0% +going to lay out a set of measures that +we think will be important so if I want + + align:start position:0% +we think will be important so if I want + + + align:start position:0% +we think will be important so if I want +to reduce under five mortality one of + + align:start position:0% +to reduce under five mortality one of + + + align:start position:0% +to reduce under five mortality one of +the things I need to do is measure under + + align:start position:0% +the things I need to do is measure under + + + align:start position:0% +the things I need to do is measure under +five mortality to see if I'm reducing it + + align:start position:0% +five mortality to see if I'm reducing it + + + align:start position:0% +five mortality to see if I'm reducing it +right if I'm consistently trying to + + align:start position:0% +right if I'm consistently trying to + + + align:start position:0% +right if I'm consistently trying to +change things motivate + + align:start position:0% +change things motivate + + + align:start position:0% +change things motivate +employees uh uh you know build a new + + align:start position:0% +employees uh uh you know build a new + + + align:start position:0% +employees uh uh you know build a new +hospital buy some ambulances then I'm + + align:start position:0% +hospital buy some ambulances then I'm + + + align:start position:0% +hospital buy some ambulances then I'm +going to be looking to My outcome + + align:start position:0% +going to be looking to My outcome + + + align:start position:0% +going to be looking to My outcome +measure to say is it working right is it + + align:start position:0% +measure to say is it working right is it + + + align:start position:0% +measure to say is it working right is it +working now if under five mortality just + + align:start position:0% +working now if under five mortality just + + + align:start position:0% +working now if under five mortality just +stays constant predictable stable over + + align:start position:0% +stays constant predictable stable over + + + align:start position:0% +stays constant predictable stable over +time + + align:start position:0% +time + + + align:start position:0% +time +what do I how does that change my + + align:start position:0% +what do I how does that change my + + + align:start position:0% +what do I how does that change my +theory so that that would tell me my + + align:start position:0% +theory so that that would tell me my + + + align:start position:0% +theory so that that would tell me my +theory is wrong there's some learning + + align:start position:0% +theory is wrong there's some learning + + + align:start position:0% +theory is wrong there's some learning +that needs to go on I built all these + + align:start position:0% +that needs to go on I built all these + + + align:start position:0% +that needs to go on I built all these +hospitals I bought all these ambulances + + align:start position:0% +hospitals I bought all these ambulances + + + align:start position:0% +hospitals I bought all these ambulances +I motivated all these people mortality + + align:start position:0% +I motivated all these people mortality + + + align:start position:0% +I motivated all these people mortality +stayed exactly the same well guess what + + align:start position:0% +stayed exactly the same well guess what + + + align:start position:0% +stayed exactly the same well guess what +those weren't the answer to changing + + align:start position:0% +those weren't the answer to changing + + + align:start position:0% +those weren't the answer to changing +mortality something else is involved so + + align:start position:0% +mortality something else is involved so + + + align:start position:0% +mortality something else is involved so +now we have to evolve our Theory right + + align:start position:0% + + + + align:start position:0% + +so so that's exactly right that and + + align:start position:0% +so so that's exactly right that and + + + align:start position:0% +so so that's exactly right that and +that's where the learning begins so if + + align:start position:0% +that's where the learning begins so if + + + align:start position:0% +that's where the learning begins so if +we're doing quality improvement we want + + align:start position:0% +we're doing quality improvement we want + + + align:start position:0% +we're doing quality improvement we want +to we want to then change our + + align:start position:0% +to we want to then change our + + + align:start position:0% +to we want to then change our +assumptions so when the when the data + + align:start position:0% +assumptions so when the when the data + + + align:start position:0% +assumptions so when the when the data +starts to tell us that our assumptions + + align:start position:0% +starts to tell us that our assumptions + + + align:start position:0% +starts to tell us that our assumptions +are incorrect or incomplete then we need + + align:start position:0% +are incorrect or incomplete then we need + + + align:start position:0% +are incorrect or incomplete then we need +to add to them or we need to evolve them + + align:start position:0% +to add to them or we need to evolve them + + + align:start position:0% +to add to them or we need to evolve them +and then test again and test again and + + align:start position:0% +and then test again and test again and + + + align:start position:0% +and then test again and test again and +we're going to see that in just a second + + align:start position:0% +we're going to see that in just a second + + + align:start position:0% +we're going to see that in just a second +yeah that's a great question that's + + align:start position:0% +yeah that's a great question that's + + + align:start position:0% +yeah that's a great question that's +that's right + + align:start position:0% +that's right + + + align:start position:0% +that's right +on so another part of a good system is + + align:start position:0% +on so another part of a good system is + + + align:start position:0% +on so another part of a good system is +is looking to the fure future right so + + align:start position:0% +is looking to the fure future right so + + + align:start position:0% +is looking to the fure future right so +Deming called this market research right + + align:start position:0% +Deming called this market research right + + + align:start position:0% +Deming called this market research right +we might call it + + align:start position:0% +we might call it + + + align:start position:0% +we might call it +foresight if we look at Health Systems + + align:start position:0% +foresight if we look at Health Systems + + + align:start position:0% +foresight if we look at Health Systems +globally for the last 100 years or so + + align:start position:0% +globally for the last 100 years or so + + + align:start position:0% +globally for the last 100 years or so +most of them have been built to focus on + + align:start position:0% +most of them have been built to focus on + + + align:start position:0% +most of them have been built to focus on +acute care people get sick they go to + + align:start position:0% +acute care people get sick they go to + + + align:start position:0% +acute care people get sick they go to +the hospital we admit them we get them + + align:start position:0% +the hospital we admit them we get them + + + align:start position:0% +the hospital we admit them we get them +better we send them home but what's + + align:start position:0% +better we send them home but what's + + + align:start position:0% +better we send them home but what's +coming next what's the big issue that's + + align:start position:0% +coming next what's the big issue that's + + + align:start position:0% +coming next what's the big issue that's +coming yeah chronic care right think + + align:start position:0% +coming yeah chronic care right think + + + align:start position:0% +coming yeah chronic care right think +think about think about Africa right for + + align:start position:0% +think about think about Africa right for + + + align:start position:0% +think about think about Africa right for +a second HIV big problem there right + + align:start position:0% +a second HIV big problem there right + + + align:start position:0% +a second HIV big problem there right +right it used to be for the last 10 15 + + align:start position:0% +right it used to be for the last 10 15 + + + align:start position:0% +right it used to be for the last 10 15 +years we were really focused on delivery + + align:start position:0% +years we were really focused on delivery + + + align:start position:0% +years we were really focused on delivery +of anr anti retroviral medication to + + align:start position:0% +of anr anti retroviral medication to + + + align:start position:0% +of anr anti retroviral medication to +people in Africa right in an acute care + + align:start position:0% +people in Africa right in an acute care + + + align:start position:0% +people in Africa right in an acute care +environment and suddenly we're waking up + + align:start position:0% +environment and suddenly we're waking up + + + align:start position:0% +environment and suddenly we're waking up +to the realization we've got to actually + + align:start position:0% +to the realization we've got to actually + + + align:start position:0% +to the realization we've got to actually +provide chronic care to these same + + align:start position:0% +provide chronic care to these same + + + align:start position:0% +provide chronic care to these same +people indefinitely right and that's + + align:start position:0% +people indefinitely right and that's + + + align:start position:0% +people indefinitely right and that's +really really important it's really + + align:start position:0% +really really important it's really + + + align:start position:0% +really really important it's really +important to have the foresight and to + + align:start position:0% +important to have the foresight and to + + + align:start position:0% +important to have the foresight and to +have a mechanism for looking for what's + + align:start position:0% +have a mechanism for looking for what's + + + align:start position:0% +have a mechanism for looking for what's +next so if we want to continue to be + + align:start position:0% +next so if we want to continue to be + + + align:start position:0% +next so if we want to continue to be +relevant to our customers to our clients + + align:start position:0% +relevant to our customers to our clients + + + align:start position:0% +relevant to our customers to our clients +we need to be paying attention to what + + align:start position:0% +we need to be paying attention to what + + + align:start position:0% +we need to be paying attention to what +their needs are going to be not just + + align:start position:0% +their needs are going to be not just + + + align:start position:0% +their needs are going to be not just +right now but what they're going to be + + align:start position:0% +right now but what they're going to be + + + align:start position:0% +right now but what they're going to be +in the future yeah so having that + + align:start position:0% +in the future yeah so having that + + + align:start position:0% +in the future yeah so having that +process of work articulated for any + + align:start position:0% +process of work articulated for any + + + align:start position:0% +process of work articulated for any +system is important and if you look at + + align:start position:0% +system is important and if you look at + + + align:start position:0% +system is important and if you look at +really successful organizations whether + + align:start position:0% +really successful organizations whether + + + align:start position:0% +really successful organizations whether +their health systems or corporations or + + align:start position:0% +their health systems or corporations or + + + align:start position:0% +their health systems or corporations or +whatever they have that they're looking + + align:start position:0% +whatever they have that they're looking + + + align:start position:0% +whatever they have that they're looking +to the + + align:start position:0% +to the + + + align:start position:0% +to the +Future some of them in the case of like + + align:start position:0% +Future some of them in the case of like + + + align:start position:0% +Future some of them in the case of like +apple and apps they're inventing the + + align:start position:0% +apple and apps they're inventing the + + + align:start position:0% +apple and apps they're inventing the +future they're telling us what we need + + align:start position:0% +future they're telling us what we need + + + align:start position:0% +future they're telling us what we need +before we know we need it right okay + + align:start position:0% +before we know we need it right okay + + + align:start position:0% +before we know we need it right okay +all of that needs to feed into a + + align:start position:0% +all of that needs to feed into a + + + align:start position:0% +all of that needs to feed into a +mechanism which is a plan to improve + + align:start position:0% +mechanism which is a plan to improve + + + align:start position:0% +mechanism which is a plan to improve +right we want the ability to improve + + align:start position:0% +right we want the ability to improve + + + align:start position:0% +right we want the ability to improve +something we need to actually have a + + align:start position:0% +something we need to actually have a + + + align:start position:0% +something we need to actually have a +mechanism for doing that we need to have + + align:start position:0% +mechanism for doing that we need to have + + + align:start position:0% +mechanism for doing that we need to have +that in place okay and then we actually + + align:start position:0% +that in place okay and then we actually + + + align:start position:0% +that in place okay and then we actually +need the work of doing that now all of + + align:start position:0% +need the work of doing that now all of + + + align:start position:0% +need the work of doing that now all of +that is different from delivery of care + + align:start position:0% +that is different from delivery of care + + + align:start position:0% +that is different from delivery of care +to patients or manufactured of product + + align:start position:0% +to patients or manufactured of product + + + align:start position:0% +to patients or manufactured of product +right that's all different that's not + + align:start position:0% +right that's all different that's not + + + align:start position:0% +right that's all different that's not +the work of the caregivers who's that + + align:start position:0% +the work of the caregivers who's that + + + align:start position:0% +the work of the caregivers who's that +the work + + align:start position:0% + + + + align:start position:0% + +of who does that stuff + + align:start position:0% + + + + align:start position:0% + +who who who has the power to change a + + align:start position:0% +who who who has the power to change a + + + align:start position:0% +who who who has the power to change a +system is it the + + align:start position:0% + + + + align:start position:0% + +nurse yeah it's that minister of Health + + align:start position:0% +nurse yeah it's that minister of Health + + + align:start position:0% +nurse yeah it's that minister of Health +right it's that CEO of the hospital it's + + align:start position:0% +right it's that CEO of the hospital it's + + + align:start position:0% +right it's that CEO of the hospital it's +those senior leaders who had the ability + + align:start position:0% +those senior leaders who had the ability + + + align:start position:0% +those senior leaders who had the ability +to say actually we're going to change + + align:start position:0% +to say actually we're going to change + + + align:start position:0% +to say actually we're going to change +our policy here we know that we need to + + align:start position:0% +our policy here we know that we need to + + + align:start position:0% +our policy here we know that we need to +do something different in the future so + + align:start position:0% +do something different in the future so + + + align:start position:0% +do something different in the future so +this is the role of management and that + + align:start position:0% +this is the role of management and that + + + align:start position:0% +this is the role of management and that +role of improvement and redesign + + align:start position:0% +role of improvement and redesign + + + align:start position:0% +role of improvement and redesign +constantly is is the role of Management + + align:start position:0% +constantly is is the role of Management + + + align:start position:0% +constantly is is the role of Management +workers can help you understand where + + align:start position:0% +workers can help you understand where + + + align:start position:0% +workers can help you understand where +the process is broken they can tell you + + align:start position:0% +the process is broken they can tell you + + + align:start position:0% +the process is broken they can tell you +when you're getting that gray elephant + + align:start position:0% +when you're getting that gray elephant + + + align:start position:0% +when you're getting that gray elephant +when when what you really want is a pink + + align:start position:0% +when when what you really want is a pink + + + align:start position:0% +when when what you really want is a pink +elephant right but it's up to the + + align:start position:0% +elephant right but it's up to the + + + align:start position:0% +elephant right but it's up to the +managers to empower the workers to begin + + align:start position:0% +managers to empower the workers to begin + + + align:start position:0% +managers to empower the workers to begin +to make changes so that's going to be a + + align:start position:0% +to make changes so that's going to be a + + + align:start position:0% +to make changes so that's going to be a +critically important concept there's one + + align:start position:0% +critically important concept there's one + + + align:start position:0% +critically important concept there's one +other thing that's missing if I'm + + align:start position:0% +other thing that's missing if I'm + + + align:start position:0% +other thing that's missing if I'm +providing surgical care uh and I bring + + align:start position:0% +providing surgical care uh and I bring + + + align:start position:0% +providing surgical care uh and I bring +in my first patient of the day and get + + align:start position:0% +in my first patient of the day and get + + + align:start position:0% +in my first patient of the day and get +my surgical team in there and do surgery + + align:start position:0% +my surgical team in there and do surgery + + + align:start position:0% +my surgical team in there and do surgery +and then I wheel out to the ICU to get + + align:start position:0% +and then I wheel out to the ICU to get + + + align:start position:0% +and then I wheel out to the ICU to get +better and I go back in can I just go + + align:start position:0% +better and I go back in can I just go + + + align:start position:0% +better and I go back in can I just go +ahead and start another + + align:start position:0% + + + + align:start position:0% + +surgery no we got to have somebody who + + align:start position:0% +surgery no we got to have somebody who + + + align:start position:0% +surgery no we got to have somebody who +comes in and cleans up right all that + + align:start position:0% +comes in and cleans up right all that + + + align:start position:0% +comes in and cleans up right all that +Blood and Guts and stuff everywhere and + + align:start position:0% +Blood and Guts and stuff everywhere and + + + align:start position:0% +Blood and Guts and stuff everywhere and +infection could be rampant that's not + + align:start position:0% +infection could be rampant that's not + + + align:start position:0% +infection could be rampant that's not +good so we have a whole set of support + + align:start position:0% +good so we have a whole set of support + + + align:start position:0% +good so we have a whole set of support +processes we have a whole set of work + + align:start position:0% +processes we have a whole set of work + + + align:start position:0% +processes we have a whole set of work +that's focused on empowering our ability + + align:start position:0% +that's focused on empowering our ability + + + align:start position:0% +that's focused on empowering our ability +to provide the main stay right all the + + align:start position:0% +to provide the main stay right all the + + + align:start position:0% +to provide the main stay right all the +things that we need in order order to + + align:start position:0% +things that we need in order order to + + + align:start position:0% +things that we need in order order to +keep the day-to-day running well right + + align:start position:0% +keep the day-to-day running well right + + + align:start position:0% +keep the day-to-day running well right +so those can be things like maintenance + + align:start position:0% +so those can be things like maintenance + + + align:start position:0% +so those can be things like maintenance +it Finance all these types of + + align:start position:0% +it Finance all these types of + + + align:start position:0% +it Finance all these types of +departments that are critically + + align:start position:0% +departments that are critically + + + align:start position:0% +departments that are critically +important they don't actually provide + + align:start position:0% +important they don't actually provide + + + align:start position:0% +important they don't actually provide +care directly to patients but they + + align:start position:0% +care directly to patients but they + + + align:start position:0% +care directly to patients but they +create the environment by which we can + + align:start position:0% +create the environment by which we can + + + align:start position:0% +create the environment by which we can +provide care to patients right now + + align:start position:0% +provide care to patients right now + + + align:start position:0% +provide care to patients right now +you'll notice there's no chronology here + + align:start position:0% +you'll notice there's no chronology here + + + align:start position:0% +you'll notice there's no chronology here +there's no beginning there's no end it's + + align:start position:0% +there's no beginning there's no end it's + + + align:start position:0% +there's no beginning there's no end it's +quite circular that's + + align:start position:0% + + + + align:start position:0% + +important sure + + align:start position:0% + + + + align:start position:0% + +this balance between the feedback and + + align:start position:0% +this balance between the feedback and + + + align:start position:0% +this balance between the feedback and +the assumptions a lot of + + align:start position:0% + + + + align:start position:0% + +timei organizations or even governmental + + align:start position:0% +timei organizations or even governmental + + + align:start position:0% +timei organizations or even governmental +agencies they even though their + + align:start position:0% +agencies they even though their + + + align:start position:0% +agencies they even though their +assumptions + + align:start position:0% +assumptions + + + align:start position:0% +assumptions +are contradicted by the feedback they + + align:start position:0% +are contradicted by the feedback they + + + align:start position:0% +are contradicted by the feedback they +still assumption they + + align:start position:0% +still assumption they + + + align:start position:0% +still assumption they +continue + + align:start position:0% +continue + + + align:start position:0% +continue +ofil everyone know + + align:start position:0% + + + + align:start position:0% + +I couldn't agree + + align:start position:0% +I couldn't agree + + + align:start position:0% +I couldn't agree +more it's it's a tremendous problem and + + align:start position:0% +more it's it's a tremendous problem and + + + align:start position:0% +more it's it's a tremendous problem and +why do you think that + + align:start position:0% +why do you think that + + + align:start position:0% +why do you think that +is because + + align:start position:0% + + + + align:start position:0% + +and could go + + align:start position:0% +and could go + + + align:start position:0% +and could go +beyond + + align:start position:0% + + + + align:start position:0% + +down develop + + align:start position:0% + + + + align:start position:0% + +countries developing countries so like + + align:start position:0% +countries developing countries so like + + + align:start position:0% +countries developing countries so like +all the knowledge is on the developed + + align:start position:0% +all the knowledge is on the developed + + + align:start position:0% +all the knowledge is on the developed +country side + + align:start position:0% +country side + + + align:start position:0% +country side +sometimes they say those feedback are + + align:start position:0% +sometimes they say those feedback are + + + align:start position:0% +sometimes they say those feedback are +not they don't have we can't trust those + + align:start position:0% +not they don't have we can't trust those + + + align:start position:0% +not they don't have we can't trust those +feedbacks because they don't have the + + align:start position:0% +feedbacks because they don't have the + + + align:start position:0% +feedbacks because they don't have the +knowledge have + + align:start position:0% +knowledge have + + + align:start position:0% +knowledge have +knowledge it's a + + align:start position:0% + + + + align:start position:0% + +big + + align:start position:0% + + + + align:start position:0% + +people we trust their capacity we trust + + align:start position:0% +people we trust their capacity we trust + + + align:start position:0% +people we trust their capacity we trust +their feedback the way they process + + align:start position:0% + + + + align:start position:0% + +enties so it's + + align:start position:0% +enties so it's + + + align:start position:0% +enties so it's +big it's a huge issue can we see them as + + align:start position:0% +big it's a huge issue can we see them as + + + align:start position:0% +big it's a huge issue can we see them as +we are + + align:start position:0% + + + + align:start position:0% + +yeah I I I think it is a deep problem + + align:start position:0% +yeah I I I think it is a deep problem + + + align:start position:0% +yeah I I I think it is a deep problem +and I think what you're describing in my + + align:start position:0% +and I think what you're describing in my + + + align:start position:0% +and I think what you're describing in my +mind is a disconnect between the feedack + + align:start position:0% +mind is a disconnect between the feedack + + + align:start position:0% +mind is a disconnect between the feedack +that's coming through and the and people + + align:start position:0% +that's coming through and the and people + + + align:start position:0% +that's coming through and the and people +not being receptive to it we've got 50 + + align:start position:0% +not being receptive to it we've got 50 + + + align:start position:0% +not being receptive to it we've got 50 +60 years of case studies of development + + align:start position:0% +60 years of case studies of development + + + align:start position:0% +60 years of case studies of development +projects that + + align:start position:0% +projects that + + + align:start position:0% +projects that +have failed right they haven't done well + + align:start position:0% +have failed right they haven't done well + + + align:start position:0% +have failed right they haven't done well +and we haven't done a good job of + + align:start position:0% +and we haven't done a good job of + + + align:start position:0% +and we haven't done a good job of +learning from that failure quality + + align:start position:0% +learning from that failure quality + + + align:start position:0% +learning from that failure quality +improvement at its core is about failing + + align:start position:0% +improvement at its core is about failing + + + align:start position:0% +improvement at its core is about failing +often to succeed sooner it's about + + align:start position:0% +often to succeed sooner it's about + + + align:start position:0% +often to succeed sooner it's about +learning from failure establishing + + align:start position:0% +learning from failure establishing + + + align:start position:0% +learning from failure establishing +feedback mechanisms that we can learn + + align:start position:0% +feedback mechanisms that we can learn + + + align:start position:0% +feedback mechanisms that we can learn +from rather than putting the blinders on + + align:start position:0% +from rather than putting the blinders on + + + align:start position:0% +from rather than putting the blinders on +and just going with our assumptions so + + align:start position:0% +and just going with our assumptions so + + + align:start position:0% +and just going with our assumptions so +we have to be open if we're going to be + + align:start position:0% +we have to be open if we're going to be + + + align:start position:0% +we have to be open if we're going to be +doing quality improvement we have to be + + align:start position:0% +doing quality improvement we have to be + + + align:start position:0% +doing quality improvement we have to be +open to constantly learning and if a + + align:start position:0% +open to constantly learning and if a + + + align:start position:0% +open to constantly learning and if a +project fails we need to actually say + + align:start position:0% +project fails we need to actually say + + + align:start position:0% +project fails we need to actually say +why did it fail was it you know was it + + align:start position:0% +why did it fail was it you know was it + + + align:start position:0% +why did it fail was it you know was it +because we had bad assumptions maybe was + + align:start position:0% +because we had bad assumptions maybe was + + + align:start position:0% +because we had bad assumptions maybe was +it because we had bad people probably + + align:start position:0% +it because we had bad people probably + + + align:start position:0% +it because we had bad people probably +not right it's those things what's hard + + align:start position:0% +not right it's those things what's hard + + + align:start position:0% +not right it's those things what's hard +is getting leaders in place who have + + align:start position:0% +is getting leaders in place who have + + + align:start position:0% +is getting leaders in place who have +that perspective who have the ability to + + align:start position:0% +that perspective who have the ability to + + + align:start position:0% +that perspective who have the ability to +have a systems View and to actually + + align:start position:0% +have a systems View and to actually + + + align:start position:0% +have a systems View and to actually +understand how they can use data to + + align:start position:0% +understand how they can use data to + + + align:start position:0% +understand how they can use data to +their advantage to manage and redesign + + align:start position:0% +their advantage to manage and redesign + + + align:start position:0% +their advantage to manage and redesign +their systems that would be my thinking + + align:start position:0% +their systems that would be my thinking + + + align:start position:0% +their systems that would be my thinking +but I I see it all the time I think + + align:start position:0% +but I I see it all the time I think + + + align:start position:0% +but I I see it all the time I think +you're absolutely right that there's + + align:start position:0% +you're absolutely right that there's + + + align:start position:0% +you're absolutely right that there's +some there's some real deep issues that + + align:start position:0% +some there's some real deep issues that + + + align:start position:0% +some there's some real deep issues that +need to be tackled but in my mind it's + + align:start position:0% +need to be tackled but in my mind it's + + + align:start position:0% +need to be tackled but in my mind it's +got to start up here it's got to start + + align:start position:0% +got to start up here it's got to start + + + align:start position:0% +got to start up here it's got to start +with the with the leadership to be able + + align:start position:0% +with the with the leadership to be able + + + align:start position:0% +with the with the leadership to be able +to engage and and learn about that + + align:start position:0% +to engage and and learn about that + + + align:start position:0% +to engage and and learn about that +stuff + + align:start position:0% +stuff + + + align:start position:0% +stuff +yes I want to + + align:start position:0% +yes I want to + + + align:start position:0% +yes I want to +propose simpler reason for + + align:start position:0% +propose simpler reason for + + + align:start position:0% +propose simpler reason for +between assumtions and + + align:start position:0% +between assumtions and + + + align:start position:0% +between assumtions and +feedb in some it Tak a lot of money to + + align:start position:0% +feedb in some it Tak a lot of money to + + + align:start position:0% +feedb in some it Tak a lot of money to +get + + align:start position:0% + + + + align:start position:0% + +systems + + align:start position:0% +systems + + + align:start position:0% +systems +are problems people don't change people + + align:start position:0% +are problems people don't change people + + + align:start position:0% +are problems people don't change people +get used + + align:start position:0% +get used + + + align:start position:0% +get used +to underline everything is the fact + + align:start position:0% + + + + align:start position:0% + +Sy yeah yeah you you may absolutely be + + align:start position:0% +Sy yeah yeah you you may absolutely be + + + align:start position:0% +Sy yeah yeah you you may absolutely be +right I I think one thing that's + + align:start position:0% +right I I think one thing that's + + + align:start position:0% +right I I think one thing that's +critically important when we think about + + align:start position:0% +critically important when we think about + + + align:start position:0% +critically important when we think about +quality improvement is we're talking + + align:start position:0% +quality improvement is we're talking + + + align:start position:0% +quality improvement is we're talking +about + + align:start position:0% +about + + + align:start position:0% +about +continuous redesign of an existing + + align:start position:0% +continuous redesign of an existing + + + align:start position:0% +continuous redesign of an existing +system right so it's important from our + + align:start position:0% +system right so it's important from our + + + align:start position:0% +system right so it's important from our +perspective if we're going to be + + align:start position:0% +perspective if we're going to be + + + align:start position:0% +perspective if we're going to be +advising people or we're going to be + + align:start position:0% +advising people or we're going to be + + + align:start position:0% +advising people or we're going to be +helping them to improve that we're not + + align:start position:0% +helping them to improve that we're not + + + align:start position:0% +helping them to improve that we're not +necessarily proposing to eliminate + + align:start position:0% +necessarily proposing to eliminate + + + align:start position:0% +necessarily proposing to eliminate +everything that's existed before right + + align:start position:0% +everything that's existed before right + + + align:start position:0% +everything that's existed before right +the world is is broken in many ways we + + align:start position:0% +the world is is broken in many ways we + + + align:start position:0% +the world is is broken in many ways we +have to work to improve what we have + + align:start position:0% +have to work to improve what we have + + + align:start position:0% +have to work to improve what we have +that's our starting place I could never + + align:start position:0% +that's our starting place I could never + + + align:start position:0% +that's our starting place I could never +imagine entering a you know a country or + + align:start position:0% +imagine entering a you know a country or + + + align:start position:0% +imagine entering a you know a country or +a city or a hospital or something ins + + align:start position:0% +a city or a hospital or something ins + + + align:start position:0% +a city or a hospital or something ins +saying actually we just need to tear + + align:start position:0% +saying actually we just need to tear + + + align:start position:0% +saying actually we just need to tear +down and build up from scratch again + + align:start position:0% +down and build up from scratch again + + + align:start position:0% +down and build up from scratch again +what it might be nice if we had the + + align:start position:0% +what it might be nice if we had the + + + align:start position:0% +what it might be nice if we had the +resources but I think you're right it's + + align:start position:0% +resources but I think you're right it's + + + align:start position:0% +resources but I think you're right it's +it is there now what can we do to make + + align:start position:0% +it is there now what can we do to make + + + align:start position:0% +it is there now what can we do to make +it better what can we do to constantly + + align:start position:0% +it better what can we do to constantly + + + align:start position:0% +it better what can we do to constantly +redesign that and make it better so I'm + + align:start position:0% +redesign that and make it better so I'm + + + align:start position:0% +redesign that and make it better so I'm +conscious of our time I want us to to + + align:start position:0% +conscious of our time I want us to to + + + align:start position:0% +conscious of our time I want us to to +move to another tool which is time bound + + align:start position:0% +move to another tool which is time bound + + + align:start position:0% +move to another tool which is time bound +unlike the linkage of process um but + + align:start position:0% +unlike the linkage of process um but + + + align:start position:0% +unlike the linkage of process um but +also gives us an ability to see inside + + align:start position:0% +also gives us an ability to see inside + + + align:start position:0% +also gives us an ability to see inside +the system so if we have the ability to + + align:start position:0% +the system so if we have the ability to + + + align:start position:0% +the system so if we have the ability to +articulate each of these processes okay + + align:start position:0% +articulate each of these processes okay + + + align:start position:0% +articulate each of these processes okay +we can start to see the complexity that + + align:start position:0% +we can start to see the complexity that + + + align:start position:0% +we can start to see the complexity that +exists within the organization or system + + align:start position:0% +exists within the organization or system + + + align:start position:0% +exists within the organization or system +that we're trying to improve okay The + + align:start position:0% +that we're trying to improve okay The + + + align:start position:0% +that we're trying to improve okay The +Next Step then is to actually see + + align:start position:0% +Next Step then is to actually see + + + align:start position:0% +Next Step then is to actually see +individual processes the things that + + align:start position:0% +individual processes the things that + + + align:start position:0% +individual processes the things that +we're going to focus on improving right + + align:start position:0% +we're going to focus on improving right + + + align:start position:0% +we're going to focus on improving right +and for that we would use a process + + align:start position:0% +and for that we would use a process + + + align:start position:0% +and for that we would use a process +map okay you guys have probably heard it + + align:start position:0% +map okay you guys have probably heard it + + + align:start position:0% +map okay you guys have probably heard it +referred to as other things + + align:start position:0% +referred to as other things + + + align:start position:0% +referred to as other things +flowchart causal Loop diagram value + + align:start position:0% +flowchart causal Loop diagram value + + + align:start position:0% +flowchart causal Loop diagram value +stream analysis you guys heard those + + align:start position:0% +stream analysis you guys heard those + + + align:start position:0% +stream analysis you guys heard those +terms before right pretty + + align:start position:0% +terms before right pretty + + + align:start position:0% +terms before right pretty +straightforward right this is a way now + + align:start position:0% +straightforward right this is a way now + + + align:start position:0% +straightforward right this is a way now +of saying we're actually going to get + + align:start position:0% +of saying we're actually going to get + + + align:start position:0% +of saying we're actually going to get +away from the big picture view we're + + align:start position:0% +away from the big picture view we're + + + align:start position:0% +away from the big picture view we're +going to drill down into a very specific + + align:start position:0% +going to drill down into a very specific + + + align:start position:0% +going to drill down into a very specific +focused area okay and we can do that uh + + align:start position:0% +focused area okay and we can do that uh + + + align:start position:0% +focused area okay and we can do that uh +uh using some of these tools I'm not + + align:start position:0% +uh using some of these tools I'm not + + + align:start position:0% +uh using some of these tools I'm not +going to go through this but process + + align:start position:0% +going to go through this but process + + + align:start position:0% +going to go through this but process +maps have a very specific uh language + + align:start position:0% +maps have a very specific uh language + + + align:start position:0% +maps have a very specific uh language +that they use certain shapes mean + + align:start position:0% +that they use certain shapes mean + + + align:start position:0% +that they use certain shapes mean +certain things and you'll have this so + + align:start position:0% +certain things and you'll have this so + + + align:start position:0% +certain things and you'll have this so +you can check it out later okay here's a + + align:start position:0% +you can check it out later okay here's a + + + align:start position:0% +you can check it out later okay here's a +very simple one that doesn't use all + + align:start position:0% +very simple one that doesn't use all + + + align:start position:0% +very simple one that doesn't use all +that complex language but here would be + + align:start position:0% +that complex language but here would be + + + align:start position:0% +that complex language but here would be +an example for uh uh pmtct care okay + + align:start position:0% +an example for uh uh pmtct care okay + + + align:start position:0% +an example for uh uh pmtct care okay +prevention of motherto child + + align:start position:0% +prevention of motherto child + + + align:start position:0% +prevention of motherto child +transmission of HIV right very simple + + align:start position:0% +transmission of HIV right very simple + + + align:start position:0% +transmission of HIV right very simple +process map here here we've got five six + + align:start position:0% +process map here here we've got five six + + + align:start position:0% +process map here here we've got five six +steps to uh to uh providing care to + + align:start position:0% +steps to uh to uh providing care to + + + align:start position:0% +steps to uh to uh providing care to +reduce transmission of HIV to children + + align:start position:0% +reduce transmission of HIV to children + + + align:start position:0% +reduce transmission of HIV to children +okay very very simple it shows us now + + align:start position:0% +okay very very simple it shows us now + + + align:start position:0% +okay very very simple it shows us now +the outcome that we might be measuring + + align:start position:0% +the outcome that we might be measuring + + + align:start position:0% +the outcome that we might be measuring +the process measure in this case might + + align:start position:0% +the process measure in this case might + + + align:start position:0% +the process measure in this case might +be our transmission rate okay but at + + align:start position:0% +be our transmission rate okay but at + + + align:start position:0% +be our transmission rate okay but at +each step we could measure how we're + + align:start position:0% +each step we could measure how we're + + + align:start position:0% +each step we could measure how we're +doing we could see how we're doing in + + align:start position:0% +doing we could see how we're doing in + + + align:start position:0% +doing we could see how we're doing in +terms of providing H testing we could + + align:start position:0% +terms of providing H testing we could + + + align:start position:0% +terms of providing H testing we could +see how we're doing in providing dual + + align:start position:0% +see how we're doing in providing dual + + + align:start position:0% +see how we're doing in providing dual +therapy or art uh uh to uh pregnant + + align:start position:0% +therapy or art uh uh to uh pregnant + + + align:start position:0% +therapy or art uh uh to uh pregnant +women okay we could do all of that as as + + align:start position:0% +women okay we could do all of that as as + + + align:start position:0% +women okay we could do all of that as as +uh individual uh measures or step + + align:start position:0% +uh individual uh measures or step + + + align:start position:0% +uh individual uh measures or step +measures within a particular process so + + align:start position:0% +measures within a particular process so + + + align:start position:0% +measures within a particular process so +that's an example a process map that + + align:start position:0% +that's an example a process map that + + + align:start position:0% +that's an example a process map that +helps us to get in and if we found that + + align:start position:0% +helps us to get in and if we found that + + + align:start position:0% +helps us to get in and if we found that +we were sort of falling down here our + + align:start position:0% +we were sort of falling down here our + + + align:start position:0% +we were sort of falling down here our +inability to conduct lab tests okay then + + align:start position:0% +inability to conduct lab tests okay then + + + align:start position:0% +inability to conduct lab tests okay then +that's where we might focus our + + align:start position:0% +that's where we might focus our + + + align:start position:0% +that's where we might focus our +Improvement but again data becomes + + align:start position:0% +Improvement but again data becomes + + + align:start position:0% +Improvement but again data becomes +critically important for showing us our + + align:start position:0% +critically important for showing us our + + + align:start position:0% +critically important for showing us our +current performance and where we want to + + align:start position:0% +current performance and where we want to + + + align:start position:0% +current performance and where we want to +focus our Improvement and helping us to + + align:start position:0% +focus our Improvement and helping us to + + + align:start position:0% +focus our Improvement and helping us to +re-evaluate our assumptions okay so we + + align:start position:0% +re-evaluate our assumptions okay so we + + + align:start position:0% +re-evaluate our assumptions okay so we +see a high transmission rate and we make + + align:start position:0% +see a high transmission rate and we make + + + align:start position:0% +see a high transmission rate and we make +an assumption about that transmission + + align:start position:0% +an assumption about that transmission + + + align:start position:0% +an assumption about that transmission +rate right but what this does is it + + align:start position:0% +rate right but what this does is it + + + align:start position:0% +rate right but what this does is it +allows us to go in and figure out + + align:start position:0% +allows us to go in and figure out + + + align:start position:0% +allows us to go in and figure out +exactly where the problem is it gives us + + align:start position:0% +exactly where the problem is it gives us + + + align:start position:0% +exactly where the problem is it gives us +a starting place for for that and we can + + align:start position:0% +a starting place for for that and we can + + + align:start position:0% +a starting place for for that and we can +measure each one of those + + align:start position:0% +measure each one of those + + + align:start position:0% +measure each one of those +steps here's an example from data flow + + align:start position:0% +steps here's an example from data flow + + + align:start position:0% +steps here's an example from data flow +okay some some some work can be around + + align:start position:0% +okay some some some work can be around + + + align:start position:0% +okay some some some work can be around +the information uh uh that's flowing + + align:start position:0% +the information uh uh that's flowing + + + align:start position:0% +the information uh uh that's flowing +through a system right patients flow + + align:start position:0% +through a system right patients flow + + + align:start position:0% +through a system right patients flow +through a system but so does information + + align:start position:0% +through a system but so does information + + + align:start position:0% +through a system but so does information +about them right and that can be + + align:start position:0% +about them right and that can be + + + align:start position:0% +about them right and that can be +critically important as well I mean it's + + align:start position:0% +critically important as well I mean it's + + + align:start position:0% +critically important as well I mean it's +a it's a terribly important thing it's + + align:start position:0% +a it's a terribly important thing it's + + + align:start position:0% +a it's a terribly important thing it's +the focus of why we're here we need + + align:start position:0% +the focus of why we're here we need + + + align:start position:0% +the focus of why we're here we need +information we need good information + + align:start position:0% +information we need good information + + + align:start position:0% +information we need good information +systems in in order to understand + + align:start position:0% +systems in in order to understand + + + align:start position:0% +systems in in order to understand +performance so that we can improve care + + align:start position:0% +performance so that we can improve care + + + align:start position:0% +performance so that we can improve care +delivery for patients right if we are uh + + align:start position:0% +delivery for patients right if we are uh + + + align:start position:0% +delivery for patients right if we are uh +having mistakes take place in the + + align:start position:0% +having mistakes take place in the + + + align:start position:0% +having mistakes take place in the +transfer of information or even in the + + align:start position:0% +transfer of information or even in the + + + align:start position:0% +transfer of information or even in the +recording of information at individual + + align:start position:0% +recording of information at individual + + + align:start position:0% +recording of information at individual +locations then we're in trouble right so + + align:start position:0% +locations then we're in trouble right so + + + align:start position:0% +locations then we're in trouble right so +as much as we might map a care Journey + + align:start position:0% +as much as we might map a care Journey + + + align:start position:0% +as much as we might map a care Journey +for an individual patient as in the + + align:start position:0% +for an individual patient as in the + + + align:start position:0% +for an individual patient as in the +process map before we might want to map + + align:start position:0% +process map before we might want to map + + + align:start position:0% +process map before we might want to map +also the data Journey okay and so as you + + align:start position:0% +also the data Journey okay and so as you + + + align:start position:0% +also the data Journey okay and so as you +think about your projects you might + + align:start position:0% +think about your projects you might + + + align:start position:0% +think about your projects you might +think about + + align:start position:0% +think about + + + align:start position:0% +think about +how is data moving for what we're for + + align:start position:0% +how is data moving for what we're for + + + align:start position:0% +how is data moving for what we're for +for for for us you know what is the + + align:start position:0% +for for for us you know what is the + + + align:start position:0% +for for for us you know what is the +information where is it first being + + align:start position:0% +information where is it first being + + + align:start position:0% +information where is it first being +captured is it being aggregated anywhere + + align:start position:0% +captured is it being aggregated anywhere + + + align:start position:0% +captured is it being aggregated anywhere +is it moving from one location to + + align:start position:0% +is it moving from one location to + + + align:start position:0% +is it moving from one location to +another because just like a patient data + + align:start position:0% +another because just like a patient data + + + align:start position:0% +another because just like a patient data +errors can be introduced whenever + + align:start position:0% +errors can be introduced whenever + + + align:start position:0% +errors can be introduced whenever +there's a handoff right whenever there's + + align:start position:0% +there's a handoff right whenever there's + + + align:start position:0% +there's a handoff right whenever there's +something that's different or changes we + + align:start position:0% +something that's different or changes we + + + align:start position:0% +something that's different or changes we +see that all the time okay we see big + + align:start position:0% +see that all the time okay we see big + + + align:start position:0% +see that all the time okay we see big +errors get you know data entry errors + + align:start position:0% +errors get you know data entry errors + + + align:start position:0% +errors get you know data entry errors +right all that kind of stuff so data has + + align:start position:0% +right all that kind of stuff so data has + + + align:start position:0% +right all that kind of stuff so data has +its own own flow as well having an + + align:start position:0% +its own own flow as well having an + + + align:start position:0% +its own own flow as well having an +ability to map that can help us to + + align:start position:0% +ability to map that can help us to + + + align:start position:0% +ability to map that can help us to +Target where we would like to leverage + + align:start position:0% +Target where we would like to leverage + + + align:start position:0% +Target where we would like to leverage +Improvement where we would like to make + + align:start position:0% +Improvement where we would like to make + + + align:start position:0% +Improvement where we would like to make +a change to our + + align:start position:0% +a change to our + + + align:start position:0% +a change to our +system all + + align:start position:0% +system all + + + align:start position:0% +system all +right how are we doing on time + + align:start position:0% +right how are we doing on time + + + align:start position:0% +right how are we doing on time +Le good hour oh really all + + align:start position:0% + + + + align:start position:0% + +right all right setting names so this is + + align:start position:0% +right all right setting names so this is + + + align:start position:0% +right all right setting names so this is +the beginning this is where we've + + align:start position:0% +the beginning this is where we've + + + align:start position:0% +the beginning this is where we've +articulated what we believe and now + + align:start position:0% +articulated what we believe and now + + + align:start position:0% +articulated what we believe and now +we're gonna we're gonna we're going to + + align:start position:0% +we're gonna we're gonna we're going to + + + align:start position:0% +we're gonna we're gonna we're going to +start off and say what it is we want to + + align:start position:0% +start off and say what it is we want to + + + align:start position:0% +start off and say what it is we want to +accomplish okay so here's something + + align:start position:0% +accomplish okay so here's something + + + align:start position:0% +accomplish okay so here's something +about setting a name if you want to + + align:start position:0% +about setting a name if you want to + + + align:start position:0% +about setting a name if you want to +improve a data system or you want to + + align:start position:0% +improve a data system or you want to + + + align:start position:0% +improve a data system or you want to +improve a care system I'm going to + + align:start position:0% +improve a care system I'm going to + + + align:start position:0% +improve a care system I'm going to +challenge you with this statement + + align:start position:0% +challenge you with this statement + + + align:start position:0% +challenge you with this statement +whatever you want to accomplish should + + align:start position:0% +whatever you want to accomplish should + + + align:start position:0% +whatever you want to accomplish should +be + + align:start position:0% +be + + + align:start position:0% +be +impossible within the current system + + align:start position:0% +impossible within the current system + + + align:start position:0% +impossible within the current system +should be impossible a lot of people + + align:start position:0% +should be impossible a lot of people + + + align:start position:0% +should be impossible a lot of people +will laugh at that why would you say + + align:start position:0% +will laugh at that why would you say + + + align:start position:0% +will laugh at that why would you say +that Brandon why do you guys think I + + align:start position:0% +that Brandon why do you guys think I + + + align:start position:0% +that Brandon why do you guys think I +said + + align:start position:0% + + + + align:start position:0% + +that yeah your + + align:start position:0% + + + + align:start position:0% + +it is + + align:start position:0% +it is + + + align:start position:0% +it is +possible exactly every system perfectly + + align:start position:0% +possible exactly every system perfectly + + + align:start position:0% +possible exactly every system perfectly +designed to achieve the results it + + align:start position:0% +designed to achieve the results it + + + align:start position:0% +designed to achieve the results it +gets that's right wouldn't need changes + + align:start position:0% +gets that's right wouldn't need changes + + + align:start position:0% +gets that's right wouldn't need changes +if you were already achieving right so + + align:start position:0% +if you were already achieving right so + + + align:start position:0% +if you were already achieving right so +that's what I mean by impossible okay it + + align:start position:0% +that's what I mean by impossible okay it + + + align:start position:0% +that's what I mean by impossible okay it +requires transformational change it + + align:start position:0% +requires transformational change it + + + align:start position:0% +requires transformational change it +requires you to do something that is + + align:start position:0% +requires you to do something that is + + + align:start position:0% +requires you to do something that is +fundamentally different than what's + + align:start position:0% +fundamentally different than what's + + + align:start position:0% +fundamentally different than what's +happening right now in the status quo + + align:start position:0% +happening right now in the status quo + + + align:start position:0% +happening right now in the status quo +right so that transformational + + align:start position:0% +right so that transformational + + + align:start position:0% +right so that transformational +change is is a redesign of the system or + + align:start position:0% +change is is a redesign of the system or + + + align:start position:0% +change is is a redesign of the system or +redesign of an individual process within + + align:start position:0% +redesign of an individual process within + + + align:start position:0% +redesign of an individual process within +the system okay and that fundamental + + align:start position:0% +the system okay and that fundamental + + + align:start position:0% +the system okay and that fundamental +change will yield a change in + + align:start position:0% +change will yield a change in + + + align:start position:0% +change will yield a change in +performance right Better or Worse okay + + align:start position:0% +performance right Better or Worse okay + + + align:start position:0% +performance right Better or Worse okay +so in terms of when you're setting a + + align:start position:0% +so in terms of when you're setting a + + + align:start position:0% +so in terms of when you're setting a +name it should be ambitious it it has to + + align:start position:0% +name it should be ambitious it it has to + + + align:start position:0% +name it should be ambitious it it has to +be measurable okay it needs to be time + + align:start position:0% +be measurable okay it needs to be time + + + align:start position:0% +be measurable okay it needs to be time +limited and it needs to be as specific + + align:start position:0% +limited and it needs to be as specific + + + align:start position:0% +limited and it needs to be as specific +as possible right so often we come + + align:start position:0% +as possible right so often we come + + + align:start position:0% +as possible right so often we come +across Improvement initiatives that are + + align:start position:0% +across Improvement initiatives that are + + + align:start position:0% +across Improvement initiatives that are +vague right what's an example of a vague + + align:start position:0% +vague right what's an example of a vague + + + align:start position:0% +vague right what's an example of a vague +Improvement initiative I would love to + + align:start position:0% +Improvement initiative I would love to + + + align:start position:0% +Improvement initiative I would love to +reduce child mortality in the + + align:start position:0% + + + + align:start position:0% + +world that's vague right that's not an a + + align:start position:0% +world that's vague right that's not an a + + + align:start position:0% +world that's vague right that's not an a +that's a that's something else I'm not + + align:start position:0% +that's a that's something else I'm not + + + align:start position:0% +that's a that's something else I'm not +sure what that is I want to reduce under + + align:start position:0% +sure what that is I want to reduce under + + + align:start position:0% +sure what that is I want to reduce under +five mortality in one District by + + align:start position:0% +five mortality in one District by + + + align:start position:0% +five mortality in one District by +40% by January 2012 now that's specific + + align:start position:0% +40% by January 2012 now that's specific + + + align:start position:0% +40% by January 2012 now that's specific +it's time limited it's measurable right + + align:start position:0% +it's time limited it's measurable right + + + align:start position:0% +it's time limited it's measurable right +it gives me a geographic location to to + + align:start position:0% +it gives me a geographic location to to + + + align:start position:0% +it gives me a geographic location to to +fixate on now we're talking about + + align:start position:0% +fixate on now we're talking about + + + align:start position:0% +fixate on now we're talking about +something that we could actually start + + align:start position:0% +something that we could actually start + + + align:start position:0% +something that we could actually start +to wrap our minds around we're starting + + align:start position:0% +to wrap our minds around we're starting + + + align:start position:0% +to wrap our minds around we're starting +to draw that circle around our system + + align:start position:0% +to draw that circle around our system + + + align:start position:0% +to draw that circle around our system +where we're going to put the boundaries + + align:start position:0% +where we're going to put the boundaries + + + align:start position:0% +where we're going to put the boundaries +of what we try to improve okay does that + + align:start position:0% +of what we try to improve okay does that + + + align:start position:0% +of what we try to improve okay does that +make + + align:start position:0% +make + + + align:start position:0% +make +sense yes shouldn't you already + + align:start position:0% +sense yes shouldn't you already + + + align:start position:0% +sense yes shouldn't you already +understand the system before you try to + + align:start position:0% +understand the system before you try to + + + align:start position:0% +understand the system before you try to +change it like if you set your aims + + align:start position:0% +change it like if you set your aims + + + align:start position:0% +change it like if you set your aims +before you actually understand the + + align:start position:0% +before you actually understand the + + + align:start position:0% +before you actually understand the +system isn't it + + align:start position:0% +system isn't it + + + align:start position:0% +system isn't it +backwards I would argue yes I mean I + + align:start position:0% +backwards I would argue yes I mean I + + + align:start position:0% +backwards I would argue yes I mean I +think if if you don't know anything + + align:start position:0% +think if if you don't know anything + + + align:start position:0% +think if if you don't know anything +about your system you probably don't + + align:start position:0% +about your system you probably don't + + + align:start position:0% +about your system you probably don't +want to change it because you're likely + + align:start position:0% +want to change it because you're likely + + + align:start position:0% +want to change it because you're likely +to make it worse right but lots of + + align:start position:0% +to make it worse right but lots of + + + align:start position:0% +to make it worse right but lots of +people don't think that way lots of + + align:start position:0% +people don't think that way lots of + + + align:start position:0% +people don't think that way lots of +people just see an outcome that they + + align:start position:0% +people just see an outcome that they + + + align:start position:0% +people just see an outcome that they +don't like and say well I've got some + + align:start position:0% +don't like and say well I've got some + + + align:start position:0% +don't like and say well I've got some +assumptions about why that is let me put + + align:start position:0% +assumptions about why that is let me put + + + align:start position:0% +assumptions about why that is let me put +some resources towards it and see what + + align:start position:0% +some resources towards it and see what + + + align:start position:0% +some resources towards it and see what +we can do to change it without that that + + align:start position:0% +we can do to change it without that that + + + align:start position:0% +we can do to change it without that that +deeper understanding yeah definitely + + align:start position:0% +deeper understanding yeah definitely + + + align:start position:0% +deeper understanding yeah definitely +yeah good all right so what are you + + align:start position:0% +yeah good all right so what are you + + + align:start position:0% +yeah good all right so what are you +trying to accomplish time limited so how + + align:start position:0% +trying to accomplish time limited so how + + + align:start position:0% +trying to accomplish time limited so how +much and by when are the kind of things + + align:start position:0% +much and by when are the kind of things + + + align:start position:0% +much and by when are the kind of things +that you want to focus on so I would + + align:start position:0% +that you want to focus on so I would + + + align:start position:0% +that you want to focus on so I would +challenge you to do with your project + + align:start position:0% +challenge you to do with your project + + + align:start position:0% +challenge you to do with your project +teams right is as you get together for + + align:start position:0% +teams right is as you get together for + + + align:start position:0% +teams right is as you get together for +the first time think about the system + + align:start position:0% +the first time think about the system + + + align:start position:0% +the first time think about the system +where are you going to draw your circle + + align:start position:0% +where are you going to draw your circle + + + align:start position:0% +where are you going to draw your circle +right what are the processes that that + + align:start position:0% +right what are the processes that that + + + align:start position:0% +right what are the processes that that +you're working with or even just a + + align:start position:0% +you're working with or even just a + + + align:start position:0% +you're working with or even just a +single process that you're working with + + align:start position:0% +single process that you're working with + + + align:start position:0% +single process that you're working with +and then what do you know about it what + + align:start position:0% +and then what do you know about it what + + + align:start position:0% +and then what do you know about it what +information do you have that can inform + + align:start position:0% +information do you have that can inform + + + align:start position:0% +information do you have that can inform +the development of an name so for your + + align:start position:0% +the development of an name so for your + + + align:start position:0% +the development of an name so for your +team and you think about your project + + align:start position:0% +team and you think about your project + + + align:start position:0% +team and you think about your project +what are you trying to + + align:start position:0% +what are you trying to + + + align:start position:0% +what are you trying to +accomplish be as specific as you + + align:start position:0% +accomplish be as specific as you + + + align:start position:0% +accomplish be as specific as you +possibly can you got a few weeks be + + align:start position:0% +possibly can you got a few weeks be + + + align:start position:0% +possibly can you got a few weeks be +specific + + align:start position:0% + + + + align:start position:0% + +yeah it's it's it's enough to + + align:start position:0% +yeah it's it's it's enough to + + + align:start position:0% +yeah it's it's it's enough to +change yes + + align:start position:0% + + + + align:start position:0% + +definitely so I agree uh for the + + align:start position:0% +definitely so I agree uh for the + + + align:start position:0% +definitely so I agree uh for the +purposes of here learning about process + + align:start position:0% +purposes of here learning about process + + + align:start position:0% +purposes of here learning about process +Improvement this is your learning + + align:start position:0% +Improvement this is your learning + + + align:start position:0% +Improvement this is your learning +laboratory this is your opportunity to + + align:start position:0% +laboratory this is your opportunity to + + + align:start position:0% +laboratory this is your opportunity to +learn about quality improvement you're + + align:start position:0% +learn about quality improvement you're + + + align:start position:0% +learn about quality improvement you're +asking a very fundamental question which + + align:start position:0% +asking a very fundamental question which + + + align:start position:0% +asking a very fundamental question which +is how big of a circle do I draw do I + + align:start position:0% +is how big of a circle do I draw do I + + + align:start position:0% +is how big of a circle do I draw do I +draw it around a single process well if + + align:start position:0% +draw it around a single process well if + + + align:start position:0% +draw it around a single process well if +my focus is on learning yeah because + + align:start position:0% +my focus is on learning yeah because + + + align:start position:0% +my focus is on learning yeah because +that gives me something manageable if my + + align:start position:0% +that gives me something manageable if my + + + align:start position:0% +that gives me something manageable if my +focus were to actually change the + + align:start position:0% +focus were to actually change the + + + align:start position:0% +focus were to actually change the +outcome of a system then I'm going to + + align:start position:0% +outcome of a system then I'm going to + + + align:start position:0% +outcome of a system then I'm going to +need to expand that Circle to include + + align:start position:0% +need to expand that Circle to include + + + align:start position:0% +need to expand that Circle to include +some other things that are going to be + + align:start position:0% +some other things that are going to be + + + align:start position:0% +some other things that are going to be +uh participating in in driving the + + align:start position:0% +uh participating in in driving the + + + align:start position:0% +uh participating in in driving the +outcome that I'm looking for absolutely + + align:start position:0% +outcome that I'm looking for absolutely + + + align:start position:0% +outcome that I'm looking for absolutely +and that is a fundamental question that + + align:start position:0% +and that is a fundamental question that + + + align:start position:0% +and that is a fundamental question that +every quality improvement team has to + + align:start position:0% +every quality improvement team has to + + + align:start position:0% +every quality improvement team has to +answer right + + align:start position:0% +answer right + + + align:start position:0% +answer right +definitely if you're a CEO or you're a + + align:start position:0% +definitely if you're a CEO or you're a + + + align:start position:0% +definitely if you're a CEO or you're a +minister of Health it's a really hard + + align:start position:0% +minister of Health it's a really hard + + + align:start position:0% +minister of Health it's a really hard +question because now you're saying how + + align:start position:0% +question because now you're saying how + + + align:start position:0% +question because now you're saying how +do I do that strategically how do I + + align:start position:0% +do I do that strategically how do I + + + align:start position:0% +do I do that strategically how do I +choose which parts do I you know do I + + align:start position:0% +choose which parts do I you know do I + + + align:start position:0% +choose which parts do I you know do I +improve maintenance do I build a + + align:start position:0% +improve maintenance do I build a + + + align:start position:0% +improve maintenance do I build a +building here do I improve the clinical + + align:start position:0% +building here do I improve the clinical + + + align:start position:0% +building here do I improve the clinical +process of care over there can I get + + align:start position:0% +process of care over there can I get + + + align:start position:0% +process of care over there can I get +those things to line up and work + + align:start position:0% +those things to line up and work + + + align:start position:0% +those things to line up and work +together right that's that's going to be + + align:start position:0% +together right that's that's going to be + + + align:start position:0% +together right that's that's going to be +a different question be a hard question + + align:start position:0% +a different question be a hard question + + + align:start position:0% +a different question be a hard question +to answer so think about this this is my + + align:start position:0% +to answer so think about this this is my + + + align:start position:0% +to answer so think about this this is my +challenge to you okay all right when + + align:start position:0% +challenge to you okay all right when + + + align:start position:0% +challenge to you okay all right when +you're reviewing it there's some key + + align:start position:0% +you're reviewing it there's some key + + + align:start position:0% +you're reviewing it there's some key +questions that you can be asking to + + align:start position:0% +questions that you can be asking to + + + align:start position:0% +questions that you can be asking to +yourselves okay is it specific is it + + align:start position:0% +yourselves okay is it specific is it + + + align:start position:0% +yourselves okay is it specific is it +ambitious is it clear to anyone who will + + align:start position:0% +ambitious is it clear to anyone who will + + + align:start position:0% +ambitious is it clear to anyone who will +read it right so if you just went out on + + align:start position:0% +read it right so if you just went out on + + + align:start position:0% +read it right so if you just went out on +the street and said hey read this do you + + align:start position:0% +the street and said hey read this do you + + + align:start position:0% +the street and said hey read this do you +have an idea what I'm trying to do they + + align:start position:0% +have an idea what I'm trying to do they + + + align:start position:0% +have an idea what I'm trying to do they +should be able to say yes they should be + + align:start position:0% +should be able to say yes they should be + + + align:start position:0% +should be able to say yes they should be +able to read it and say yeah I got a + + align:start position:0% +able to read it and say yeah I got a + + + align:start position:0% +able to read it and say yeah I got a +good idea of what you're trying to + + align:start position:0% +good idea of what you're trying to + + + align:start position:0% +good idea of what you're trying to +accomplish if it's like that it's a good + + align:start position:0% +accomplish if it's like that it's a good + + + align:start position:0% +accomplish if it's like that it's a good +indication that you have a good handle + + align:start position:0% +indication that you have a good handle + + + align:start position:0% +indication that you have a good handle +on what it is you're trying to + + align:start position:0% +on what it is you're trying to + + + align:start position:0% +on what it is you're trying to +accomplish you have a good handle on the + + align:start position:0% +accomplish you have a good handle on the + + + align:start position:0% +accomplish you have a good handle on the +system that you're working within and + + align:start position:0% +system that you're working within and + + + align:start position:0% +system that you're working within and +that Circle that you've + + align:start position:0% +that Circle that you've + + + align:start position:0% +that Circle that you've +drawn okay and then ask people to + + align:start position:0% +drawn okay and then ask people to + + + align:start position:0% +drawn okay and then ask people to +improve it ask them where could it be + + align:start position:0% +improve it ask them where could it be + + + align:start position:0% +improve it ask them where could it be +clearer where could I improve this where + + align:start position:0% +clearer where could I improve this where + + + align:start position:0% +clearer where could I improve this where +could I make it + + align:start position:0% +could I make it + + + align:start position:0% +could I make it +better okay so the last thing I want to + + align:start position:0% +better okay so the last thing I want to + + + align:start position:0% +better okay so the last thing I want to +talk about today is the model for + + align:start position:0% +talk about today is the model for + + + align:start position:0% +talk about today is the model for +improvement and this is a very specific + + align:start position:0% +improvement and this is a very specific + + + align:start position:0% +improvement and this is a very specific +model that is uh developed from the work + + align:start position:0% +model that is uh developed from the work + + + align:start position:0% +model that is uh developed from the work +of Walter schuhart and and Edwards + + align:start position:0% +of Walter schuhart and and Edwards + + + align:start position:0% +of Walter schuhart and and Edwards +Deming okay and it's a mechanism for + + align:start position:0% +Deming okay and it's a mechanism for + + + align:start position:0% +Deming okay and it's a mechanism for +actually making changes in a system or + + align:start position:0% +actually making changes in a system or + + + align:start position:0% +actually making changes in a system or +in a + + align:start position:0% +in a + + + align:start position:0% +in a +process so it is in my mind a a really + + align:start position:0% +process so it is in my mind a a really + + + align:start position:0% +process so it is in my mind a a really +powerful mechanism um for for driving + + align:start position:0% +powerful mechanism um for for driving + + + align:start position:0% +powerful mechanism um for for driving +quality improvement it's not the only + + align:start position:0% +quality improvement it's not the only + + + align:start position:0% +quality improvement it's not the only +mechanism but it is one okay so again + + align:start position:0% +mechanism but it is one okay so again + + + align:start position:0% +mechanism but it is one okay so again +now we're we're focusing here on theory + + align:start position:0% +now we're we're focusing here on theory + + + align:start position:0% +now we're we're focusing here on theory +of knowledge constantly learning the + + align:start position:0% +of knowledge constantly learning the + + + align:start position:0% +of knowledge constantly learning the +model for improvement in many ways is + + align:start position:0% +model for improvement in many ways is + + + align:start position:0% +model for improvement in many ways is +the application of the scientific method + + align:start position:0% +the application of the scientific method + + + align:start position:0% +the application of the scientific method +through quality + + align:start position:0% +through quality + + + align:start position:0% +through quality +improvement and it's a way of engaging + + align:start position:0% +improvement and it's a way of engaging + + + align:start position:0% +improvement and it's a way of engaging +teams of people and helping to + + align:start position:0% +teams of people and helping to + + + align:start position:0% +teams of people and helping to +understand their pers perspective and + + align:start position:0% +understand their pers perspective and + + + align:start position:0% +understand their pers perspective and +getting them motivated to + + align:start position:0% +getting them motivated to + + + align:start position:0% +getting them motivated to +change okay here it is it's described uh + + align:start position:0% +change okay here it is it's described uh + + + align:start position:0% +change okay here it is it's described uh +by uh in the Improvement guide that's + + align:start position:0% +by uh in the Improvement guide that's + + + align:start position:0% +by uh in the Improvement guide that's +LLY at all there's a reference at the + + align:start position:0% +LLY at all there's a reference at the + + + align:start position:0% +LLY at all there's a reference at the +end okay it involves three questions and + + align:start position:0% +end okay it involves three questions and + + + align:start position:0% +end okay it involves three questions and +something called a plan do study act + + align:start position:0% +something called a plan do study act + + + align:start position:0% +something called a plan do study act +cycle so we'll talk about the plan to + + align:start position:0% +cycle so we'll talk about the plan to + + + align:start position:0% +cycle so we'll talk about the plan to +study act cycle in more detail in a + + align:start position:0% +study act cycle in more detail in a + + + align:start position:0% +study act cycle in more detail in a +minute but what I want to focus on for + + align:start position:0% +minute but what I want to focus on for + + + align:start position:0% +minute but what I want to focus on for +the first part are the three questions + + align:start position:0% +the first part are the three questions + + + align:start position:0% +the first part are the three questions +so when you're approaching a quality + + align:start position:0% +so when you're approaching a quality + + + align:start position:0% +so when you're approaching a quality +improvement project the three questions + + align:start position:0% +improvement project the three questions + + + align:start position:0% +improvement project the three questions +are critically important what are you + + align:start position:0% +are critically important what are you + + + align:start position:0% +are critically important what are you +trying to accomplish you can do this at + + align:start position:0% +trying to accomplish you can do this at + + + align:start position:0% +trying to accomplish you can do this at +the macro level for the project itself + + align:start position:0% +the macro level for the project itself + + + align:start position:0% +the macro level for the project itself +or you can do it for an individual + + align:start position:0% +or you can do it for an individual + + + align:start position:0% +or you can do it for an individual +learning cycle okay you can do it for an + + align:start position:0% +learning cycle okay you can do it for an + + + align:start position:0% +learning cycle okay you can do it for an +individual learning + + align:start position:0% +individual learning + + + align:start position:0% +individual learning +cycle what change can we make that will + + align:start position:0% +cycle what change can we make that will + + + align:start position:0% +cycle what change can we make that will +result in Improvement so coming out of + + align:start position:0% +result in Improvement so coming out of + + + align:start position:0% +result in Improvement so coming out of +our assumptions and our thoughts and the + + align:start position:0% +our assumptions and our thoughts and the + + + align:start position:0% +our assumptions and our thoughts and the +information that we have about our + + align:start position:0% +information that we have about our + + + align:start position:0% +information that we have about our +system what are all the things that we + + align:start position:0% +system what are all the things that we + + + align:start position:0% +system what are all the things that we +think we could do differently that we + + align:start position:0% +think we could do differently that we + + + align:start position:0% +think we could do differently that we +could change about the status quo okay + + align:start position:0% +could change about the status quo okay + + + align:start position:0% +could change about the status quo okay +and then how we know that A change is an + + align:start position:0% +and then how we know that A change is an + + + align:start position:0% +and then how we know that A change is an +improvement how are we going to measure + + align:start position:0% +improvement how are we going to measure + + + align:start position:0% +improvement how are we going to measure +whether or not what we're doing + + align:start position:0% +whether or not what we're doing + + + align:start position:0% +whether or not what we're doing +different differently is better than + + align:start position:0% +different differently is better than + + + align:start position:0% +different differently is better than +what is right now does that make sense + + align:start position:0% +what is right now does that make sense + + + align:start position:0% +what is right now does that make sense +so those three questions are important + + align:start position:0% +so those three questions are important + + + align:start position:0% +so those three questions are important +all three of them are important so that + + align:start position:0% +all three of them are important so that + + + align:start position:0% +all three of them are important so that +measurement piece is going to inform + + align:start position:0% +measurement piece is going to inform + + + align:start position:0% +measurement piece is going to inform +whether or not the changes we made are + + align:start position:0% +whether or not the changes we made are + + + align:start position:0% +whether or not the changes we made are +good and whether or not we should try + + align:start position:0% +good and whether or not we should try + + + align:start position:0% +good and whether or not we should try +something else or evolve our Theory + + align:start position:0% +something else or evolve our Theory + + + align:start position:0% +something else or evolve our Theory +right or even change our Focus all of + + align:start position:0% +right or even change our Focus all of + + + align:start position:0% +right or even change our Focus all of +that when you have them in place then + + align:start position:0% +that when you have them in place then + + + align:start position:0% +that when you have them in place then +get driven by the pdsa cycle which is a + + align:start position:0% +get driven by the pdsa cycle which is a + + + align:start position:0% +get driven by the pdsa cycle which is a +mechanism for testing change in a + + align:start position:0% +mechanism for testing change in a + + + align:start position:0% +mechanism for testing change in a +non-threatening way to a system + + align:start position:0% +non-threatening way to a system + + + align:start position:0% +non-threatening way to a system +okay all right + + align:start position:0% + + + + align:start position:0% + +so this is really the aim setting yeah + + align:start position:0% + + + + align:start position:0% + +Patrick yes we're GNA talk about that in + + align:start position:0% +Patrick yes we're GNA talk about that in + + + align:start position:0% +Patrick yes we're GNA talk about that in +in a lot of detail in just two minutes + + align:start position:0% +in a lot of detail in just two minutes + + + align:start position:0% +in a lot of detail in just two minutes +is that + + align:start position:0% +is that + + + align:start position:0% +is that +okay definitely hold on to that though + + align:start position:0% +okay definitely hold on to that though + + + align:start position:0% +okay definitely hold on to that though +don't let me get away from that right + + align:start position:0% +don't let me get away from that right + + + align:start position:0% +don't let me get away from that right +okay so what are we trying to accomplish + + align:start position:0% +okay so what are we trying to accomplish + + + align:start position:0% +okay so what are we trying to accomplish +project aim but then when we have come + + align:start position:0% +project aim but then when we have come + + + align:start position:0% +project aim but then when we have come +up with a specific change that we want + + align:start position:0% +up with a specific change that we want + + + align:start position:0% +up with a specific change that we want +to make a specific aim for testing that + + align:start position:0% +to make a specific aim for testing that + + + align:start position:0% +to make a specific aim for testing that +change right if my aim overall is to + + align:start position:0% +change right if my aim overall is to + + + align:start position:0% +change right if my aim overall is to +reduce HIV transmission but the change + + align:start position:0% +reduce HIV transmission but the change + + + align:start position:0% +reduce HIV transmission but the change +that I'm making is one to increase HIV + + align:start position:0% +that I'm making is one to increase HIV + + + align:start position:0% +that I'm making is one to increase HIV +testing then I need to have an aim just + + align:start position:0% +testing then I need to have an aim just + + + align:start position:0% +testing then I need to have an aim just +for that right I need to have an aim + + align:start position:0% +for that right I need to have an aim + + + align:start position:0% +for that right I need to have an aim +just for that so it's maybe increasing + + align:start position:0% +just for that so it's maybe increasing + + + align:start position:0% +just for that so it's maybe increasing +testing by how much where for what + + align:start position:0% +testing by how much where for what + + + align:start position:0% +testing by how much where for what +population all that kind of thing okay + + align:start position:0% +population all that kind of thing okay + + + align:start position:0% +population all that kind of thing okay +what change can we make that will result + + align:start position:0% +what change can we make that will result + + + align:start position:0% +what change can we make that will result +in an improvement so where do we go out + + align:start position:0% +in an improvement so where do we go out + + + align:start position:0% +in an improvement so where do we go out +and find change + + align:start position:0% +and find change + + + align:start position:0% +and find change +ideas how do we know what to do + + align:start position:0% +ideas how do we know what to do + + + align:start position:0% +ideas how do we know what to do +differently here are some ideas okay the + + align:start position:0% +differently here are some ideas okay the + + + align:start position:0% +differently here are some ideas okay the +first place that I'm always going to + + align:start position:0% +first place that I'm always going to + + + align:start position:0% +first place that I'm always going to +look if I'm working within a system is + + align:start position:0% +look if I'm working within a system is + + + align:start position:0% +look if I'm working within a system is +to the people who are providing the + + align:start position:0% +to the people who are providing the + + + align:start position:0% +to the people who are providing the +service remember what I said way back at + + align:start position:0% +service remember what I said way back at + + + align:start position:0% +service remember what I said way back at +the beginning about subject matter + + align:start position:0% +the beginning about subject matter + + + align:start position:0% +the beginning about subject matter +experts these are their subject matter + + align:start position:0% +experts these are their subject matter + + + align:start position:0% +experts these are their subject matter +experts these are the folks who may be + + align:start position:0% +experts these are the folks who may be + + + align:start position:0% +experts these are the folks who may be +researchers in the field and have real + + align:start position:0% +researchers in the field and have real + + + align:start position:0% +researchers in the field and have real +deep knowledge about what works and what + + align:start position:0% +deep knowledge about what works and what + + + align:start position:0% +deep knowledge about what works and what +doesn't work or they could be Frontline + + align:start position:0% +doesn't work or they could be Frontline + + + align:start position:0% +doesn't work or they could be Frontline +caregivers who are running into systems + + align:start position:0% +caregivers who are running into systems + + + align:start position:0% +caregivers who are running into systems +barriers every day who are running into + + align:start position:0% +barriers every day who are running into + + + align:start position:0% +barriers every day who are running into +things that they don't like and they're + + align:start position:0% +things that they don't like and they're + + + align:start position:0% +things that they don't like and they're +having to work around those barriers + + align:start position:0% +having to work around those barriers + + + align:start position:0% +having to work around those barriers +right they're going to be a good source + + align:start position:0% +right they're going to be a good source + + + align:start position:0% +right they're going to be a good source +for understanding what you could be + + align:start position:0% +for understanding what you could be + + + align:start position:0% +for understanding what you could be +doing differently walk into any Hospital + + align:start position:0% +doing differently walk into any Hospital + + + align:start position:0% +doing differently walk into any Hospital +in Boston after class + + align:start position:0% +in Boston after class + + + align:start position:0% +in Boston after class +today pull aside one clinician and say + + align:start position:0% +today pull aside one clinician and say + + + align:start position:0% +today pull aside one clinician and say +tomorrow when you come to work if you + + align:start position:0% +tomorrow when you come to work if you + + + align:start position:0% +tomorrow when you come to work if you +could do one thing differently what + + align:start position:0% +could do one thing differently what + + + align:start position:0% +could do one thing differently what +would it be as you would have change + + align:start position:0% +would it be as you would have change + + + align:start position:0% +would it be as you would have change +ideas coming coming out of of every + + align:start position:0% +ideas coming coming out of of every + + + align:start position:0% +ideas coming coming out of of every +pocket I mean people have things that + + align:start position:0% +pocket I mean people have things that + + + align:start position:0% +pocket I mean people have things that +that frustrate them about their job and + + align:start position:0% +that frustrate them about their job and + + + align:start position:0% +that frustrate them about their job and +they have Solutions but often they don't + + align:start position:0% +they have Solutions but often they don't + + + align:start position:0% +they have Solutions but often they don't +feel empowered to enact those Solutions + + align:start position:0% +feel empowered to enact those Solutions + + + align:start position:0% +feel empowered to enact those Solutions +right so one place to look for those + + align:start position:0% +right so one place to look for those + + + align:start position:0% +right so one place to look for those +ideas is is from the people who are who + + align:start position:0% +ideas is is from the people who are who + + + align:start position:0% +ideas is is from the people who are who +who are living it every day the clients + + align:start position:0% +who are living it every day the clients + + + align:start position:0% +who are living it every day the clients +themselves particularly in health care + + align:start position:0% +themselves particularly in health care + + + align:start position:0% +themselves particularly in health care +right we often forget about patients + + align:start position:0% +right we often forget about patients + + + align:start position:0% +right we often forget about patients +we're so focused on the system and the + + align:start position:0% +we're so focused on the system and the + + + align:start position:0% +we're so focused on the system and the +caregivers that we forget about the + + align:start position:0% +caregivers that we forget about the + + + align:start position:0% +caregivers that we forget about the +patients themselves and their needs and + + align:start position:0% +patients themselves and their needs and + + + align:start position:0% +patients themselves and their needs and +the challenges that they have to + + align:start position:0% +the challenges that they have to + + + align:start position:0% +the challenges that they have to +accessing care particularly in resource + + align:start position:0% +accessing care particularly in resource + + + align:start position:0% +accessing care particularly in resource +constrainted environments right I've + + align:start position:0% +constrainted environments right I've + + + align:start position:0% +constrainted environments right I've +worked with clinics where you know + + align:start position:0% +worked with clinics where you know + + + align:start position:0% +worked with clinics where you know +people have to travel 50 70 kilm right + + align:start position:0% +people have to travel 50 70 kilm right + + + align:start position:0% +people have to travel 50 70 kilm right +all before 8: a.m. and then wait to get + + align:start position:0% +all before 8: a.m. and then wait to get + + + align:start position:0% +all before 8: a.m. and then wait to get +care and then travel back at tremendous + + align:start position:0% +care and then travel back at tremendous + + + align:start position:0% +care and then travel back at tremendous +cost right to themselves to their family + + align:start position:0% +cost right to themselves to their family + + + align:start position:0% +cost right to themselves to their family +to their work whatever it is right are + + align:start position:0% +to their work whatever it is right are + + + align:start position:0% +to their work whatever it is right are +we taking that into account clients can + + align:start position:0% +we taking that into account clients can + + + align:start position:0% +we taking that into account clients can +have ideas about where we can do things + + align:start position:0% +have ideas about where we can do things + + + align:start position:0% +have ideas about where we can do things +differently and how we can improve our + + align:start position:0% +differently and how we can improve our + + + align:start position:0% +differently and how we can improve our +systems of course best practices and + + align:start position:0% +systems of course best practices and + + + align:start position:0% +systems of course best practices and +guidelines are important we can't forget + + align:start position:0% +guidelines are important we can't forget + + + align:start position:0% +guidelines are important we can't forget +you know that guidelines are in place + + align:start position:0% +you know that guidelines are in place + + + align:start position:0% +you know that guidelines are in place +for a reason because people have done + + align:start position:0% +for a reason because people have done + + + align:start position:0% +for a reason because people have done +some serious thinking around the topics + + align:start position:0% +some serious thinking around the topics + + + align:start position:0% +some serious thinking around the topics +and the and the processes that we're + + align:start position:0% +and the and the processes that we're + + + align:start position:0% +and the and the processes that we're +trying to improve and a lot of places + + align:start position:0% +trying to improve and a lot of places + + + align:start position:0% +trying to improve and a lot of places +have good policies and guidelines in + + align:start position:0% +have good policies and guidelines in + + + align:start position:0% +have good policies and guidelines in +place we we you know we develop great + + align:start position:0% +place we we you know we develop great + + + align:start position:0% +place we we you know we develop great +recommendations frequently at places + + align:start position:0% +recommendations frequently at places + + + align:start position:0% +recommendations frequently at places +like UNICEF World Health individual + + align:start position:0% +like UNICEF World Health individual + + + align:start position:0% +like UNICEF World Health individual +ministries of Health come up with great + + align:start position:0% +ministries of Health come up with great + + + align:start position:0% +ministries of Health come up with great +guidelines right now their their + + align:start position:0% +guidelines right now their their + + + align:start position:0% +guidelines right now their their +reliable implementation is a completely + + align:start position:0% +reliable implementation is a completely + + + align:start position:0% +reliable implementation is a completely +different matter but there could be some + + align:start position:0% +different matter but there could be some + + + align:start position:0% +different matter but there could be some +great ideas contained therein about how + + align:start position:0% +great ideas contained therein about how + + + align:start position:0% +great ideas contained therein about how +we can improve systems + + align:start position:0% +we can improve systems + + + align:start position:0% +we can improve systems +okay change + + align:start position:0% +okay change + + + align:start position:0% +okay change +Concepts these are these are something + + align:start position:0% +Concepts these are these are something + + + align:start position:0% +Concepts these are these are something +that you can uh learn more about uh but + + align:start position:0% +that you can uh learn more about uh but + + + align:start position:0% +that you can uh learn more about uh but +you know things that could be could lead + + align:start position:0% +you know things that could be could lead + + + align:start position:0% +you know things that could be could lead +to lots of different specific ideas okay + + align:start position:0% +to lots of different specific ideas okay + + + align:start position:0% +to lots of different specific ideas okay +um improve throughput eliminate waste + + align:start position:0% +um improve throughput eliminate waste + + + align:start position:0% +um improve throughput eliminate waste +these are Concepts but they could be + + align:start position:0% +these are Concepts but they could be + + + align:start position:0% +these are Concepts but they could be +leveraged into very specific actionable + + align:start position:0% +leveraged into very specific actionable + + + align:start position:0% +leveraged into very specific actionable +items now you can use structured + + align:start position:0% +items now you can use structured + + + align:start position:0% +items now you can use structured +creativity there's great thinkers people + + align:start position:0% +creativity there's great thinkers people + + + align:start position:0% +creativity there's great thinkers people +like Edward debono who have done a lot + + align:start position:0% +like Edward debono who have done a lot + + + align:start position:0% +like Edward debono who have done a lot +to help us understand how we could use + + align:start position:0% +to help us understand how we could use + + + align:start position:0% +to help us understand how we could use +structured creativity right A lot of + + align:start position:0% +structured creativity right A lot of + + + align:start position:0% +structured creativity right A lot of +people think well that person's creative + + align:start position:0% +people think well that person's creative + + + align:start position:0% +people think well that person's creative +and that person's not right but actually + + align:start position:0% +and that person's not right but actually + + + align:start position:0% +and that person's not right but actually +we can all be creative if we learn some + + align:start position:0% +we can all be creative if we learn some + + + align:start position:0% +we can all be creative if we learn some +tools to help us overcome our our normal + + align:start position:0% +tools to help us overcome our our normal + + + align:start position:0% +tools to help us overcome our our normal +perceptual sort of ruts that we get + + align:start position:0% +perceptual sort of ruts that we get + + + align:start position:0% +perceptual sort of ruts that we get +into and doing some root cause analysis + + align:start position:0% +into and doing some root cause analysis + + + align:start position:0% +into and doing some root cause analysis +right understanding the process talking + + align:start position:0% +right understanding the process talking + + + align:start position:0% +right understanding the process talking +with folks about what's wrong can often + + align:start position:0% +with folks about what's wrong can often + + + align:start position:0% +with folks about what's wrong can often +lead to + + align:start position:0% + + + + align:start position:0% + +ideas last bit how will we know that A + + align:start position:0% +ideas last bit how will we know that A + + + align:start position:0% +ideas last bit how will we know that A +change is an improvement here we've got + + align:start position:0% +change is an improvement here we've got + + + align:start position:0% +change is an improvement here we've got +to measure we have to know for an + + align:start position:0% +to measure we have to know for an + + + align:start position:0% +to measure we have to know for an +individual step in the process or for + + align:start position:0% +individual step in the process or for + + + align:start position:0% +individual step in the process or for +the whole process itself or for the the + + align:start position:0% +the whole process itself or for the the + + + align:start position:0% +the whole process itself or for the the +outcome for the whole system how we're + + align:start position:0% +outcome for the whole system how we're + + + align:start position:0% +outcome for the whole system how we're +doing this often is neglected by folks + + align:start position:0% +doing this often is neglected by folks + + + align:start position:0% +doing this often is neglected by folks +right we're interested in the patient + + align:start position:0% +right we're interested in the patient + + + align:start position:0% +right we're interested in the patient +that's right in front of us but we need + + align:start position:0% +that's right in front of us but we need + + + align:start position:0% +that's right in front of us but we need +to have the perception we need to have + + align:start position:0% +to have the perception we need to have + + + align:start position:0% +to have the perception we need to have +the awareness of what's going on around + + align:start position:0% +the awareness of what's going on around + + + align:start position:0% +the awareness of what's going on around +us okay so each change idea has to have + + align:start position:0% +us okay so each change idea has to have + + + align:start position:0% +us okay so each change idea has to have +measurement associated with it if I'm + + align:start position:0% +measurement associated with it if I'm + + + align:start position:0% +measurement associated with it if I'm +going to implement a new data system how + + align:start position:0% +going to implement a new data system how + + + align:start position:0% +going to implement a new data system how +am I going to know that that's better + + align:start position:0% +am I going to know that that's better + + + align:start position:0% +am I going to know that that's better +than the paper based system I've been + + align:start position:0% +than the paper based system I've been + + + align:start position:0% +than the paper based system I've been +using for the last 20 years what do I + + align:start position:0% +using for the last 20 years what do I + + + align:start position:0% +using for the last 20 years what do I +know about the performance of the paper + + align:start position:0% +know about the performance of the paper + + + align:start position:0% +know about the performance of the paper +based system that tells me that I need + + align:start position:0% +based system that tells me that I need + + + align:start position:0% +based system that tells me that I need +to change away from that + + align:start position:0% +to change away from that + + + align:start position:0% +to change away from that +right you've got to have a way to + + align:start position:0% +right you've got to have a way to + + + align:start position:0% +right you've got to have a way to +measure so that when you do something + + align:start position:0% +measure so that when you do something + + + align:start position:0% +measure so that when you do something +different when you try it out for the + + align:start position:0% +different when you try it out for the + + + align:start position:0% +different when you try it out for the +first time you know that it's an + + align:start position:0% +first time you know that it's an + + + align:start position:0% +first time you know that it's an +improvement so Patrick coming to your + + align:start position:0% +improvement so Patrick coming to your + + + align:start position:0% +improvement so Patrick coming to your +question what about this thing what + + align:start position:0% +question what about this thing what + + + align:start position:0% +question what about this thing what +about the plan do study act cycle so uh + + align:start position:0% +about the plan do study act cycle so uh + + + align:start position:0% +about the plan do study act cycle so uh +a lot of times it's called the Deming + + align:start position:0% +a lot of times it's called the Deming + + + align:start position:0% +a lot of times it's called the Deming +cycle Deming called it the shoe har + + align:start position:0% +cycle Deming called it the shoe har + + + align:start position:0% +cycle Deming called it the shoe har +cycle he said it got it from shoe har + + align:start position:0% +cycle he said it got it from shoe har + + + align:start position:0% +cycle he said it got it from shoe har +but really this is a way of what we call + + align:start position:0% +but really this is a way of what we call + + + align:start position:0% +but really this is a way of what we call +Rapid cycle learning it's a way of + + align:start position:0% +Rapid cycle learning it's a way of + + + align:start position:0% +Rapid cycle learning it's a way of +learning very quickly whether or not the + + align:start position:0% +learning very quickly whether or not the + + + align:start position:0% +learning very quickly whether or not the +idea we have uh will work and I'm going + + align:start position:0% +idea we have uh will work and I'm going + + + align:start position:0% +idea we have uh will work and I'm going +to tell a story and just a second about + + align:start position:0% +to tell a story and just a second about + + + align:start position:0% +to tell a story and just a second about +that it starts with a plan okay it + + align:start position:0% +that it starts with a plan okay it + + + align:start position:0% +that it starts with a plan okay it +starts with a specific aim for that + + align:start position:0% +starts with a specific aim for that + + + align:start position:0% +starts with a specific aim for that +particular change idea okay we State the + + align:start position:0% +particular change idea okay we State the + + + align:start position:0% +particular change idea okay we State the +objective what it is we're trying to + + align:start position:0% +objective what it is we're trying to + + + align:start position:0% +objective what it is we're trying to +accomplish through that I change idea + + align:start position:0% +accomplish through that I change idea + + + align:start position:0% +accomplish through that I change idea +we're trying to increase HIV testing + + align:start position:0% +we're trying to increase HIV testing + + + align:start position:0% +we're trying to increase HIV testing +we're trying to increase immunization + + align:start position:0% +we're trying to increase immunization + + + align:start position:0% +we're trying to increase immunization +rates whatever it is then we start + + align:start position:0% +rates whatever it is then we start + + + align:start position:0% +rates whatever it is then we start +answering some very specific questions + + align:start position:0% +answering some very specific questions + + + align:start position:0% +answering some very specific questions +we start answering questions like who's + + align:start position:0% +we start answering questions like who's + + + align:start position:0% +we start answering questions like who's +going to try this out right it's going + + align:start position:0% +going to try this out right it's going + + + align:start position:0% +going to try this out right it's going +to be nurse Judy + + align:start position:0% +to be nurse Judy + + + align:start position:0% +to be nurse Judy +okay she's going to try it out and when + + align:start position:0% +okay she's going to try it out and when + + + align:start position:0% +okay she's going to try it out and when +is she going to do this she's going to + + align:start position:0% +is she going to do this she's going to + + + align:start position:0% +is she going to do this she's going to +do it on Monday morning at 9:00 a.m. + + align:start position:0% +do it on Monday morning at 9:00 a.m. + + + align:start position:0% +do it on Monday morning at 9:00 a.m. +okay and where is she going to do it + + align:start position:0% +okay and where is she going to do it + + + align:start position:0% +okay and where is she going to do it +she's going to do it at Clinic X okay + + align:start position:0% +she's going to do it at Clinic X okay + + + align:start position:0% +she's going to do it at Clinic X okay +and who is she going to do it with she's + + align:start position:0% +and who is she going to do it with she's + + + align:start position:0% +and who is she going to do it with she's +going to do it on the first 10 patients + + align:start position:0% +going to do it on the first 10 patients + + + align:start position:0% +going to do it on the first 10 patients +that walk in that day it becomes very + + align:start position:0% +that walk in that day it becomes very + + + align:start position:0% +that walk in that day it becomes very +specific it's like planning a small + + align:start position:0% +specific it's like planning a small + + + align:start position:0% +specific it's like planning a small +experiment just for a single small + + align:start position:0% +experiment just for a single small + + + align:start position:0% +experiment just for a single small +moment in time right we're not talking + + align:start position:0% +moment in time right we're not talking + + + align:start position:0% +moment in time right we're not talking +about a grand plan to redesign the + + align:start position:0% +about a grand plan to redesign the + + + align:start position:0% +about a grand plan to redesign the +entire system in one cycle and it's + + align:start position:0% +entire system in one cycle and it's + + + align:start position:0% +entire system in one cycle and it's +going to take us six months or a year + + align:start position:0% +going to take us six months or a year + + + align:start position:0% +going to take us six months or a year +we're talking about something very very + + align:start position:0% +we're talking about something very very + + + align:start position:0% +we're talking about something very very +small something we can accomplish in one + + align:start position:0% +small something we can accomplish in one + + + align:start position:0% +small something we can accomplish in one +day or within one week okay something + + align:start position:0% +day or within one week okay something + + + align:start position:0% +day or within one week okay something +very very rapid cycle learning it's all + + align:start position:0% +very very rapid cycle learning it's all + + + align:start position:0% +very very rapid cycle learning it's all +about right now okay so we're going to + + align:start position:0% +about right now okay so we're going to + + + align:start position:0% +about right now okay so we're going to +plan that out we're going to articulate + + align:start position:0% +plan that out we're going to articulate + + + align:start position:0% +plan that out we're going to articulate +all of that we're going to write it all + + align:start position:0% +all of that we're going to write it all + + + align:start position:0% +all of that we're going to write it all +down and then we're going to go out and + + align:start position:0% +down and then we're going to go out and + + + align:start position:0% +down and then we're going to go out and +we're going to do it so nurse Judy + + align:start position:0% +we're going to do it so nurse Judy + + + align:start position:0% +we're going to do it so nurse Judy +Monday morning 9:00 a.m. she's waiting + + align:start position:0% +Monday morning 9:00 a.m. she's waiting + + + align:start position:0% +Monday morning 9:00 a.m. she's waiting +there for the first 10 patients at + + align:start position:0% +there for the first 10 patients at + + + align:start position:0% +there for the first 10 patients at +Clinic X to come in as those patients + + align:start position:0% +Clinic X to come in as those patients + + + align:start position:0% +Clinic X to come in as those patients +come through the door she's going to + + align:start position:0% +come through the door she's going to + + + align:start position:0% +come through the door she's going to +test the this particular change idea + + align:start position:0% +test the this particular change idea + + + align:start position:0% +test the this particular change idea +whatever it is + + align:start position:0% +whatever it is + + + align:start position:0% +whatever it is +okay might be a new data collection + + align:start position:0% +okay might be a new data collection + + + align:start position:0% +okay might be a new data collection +mechanism it might be a new way of + + align:start position:0% +mechanism it might be a new way of + + + align:start position:0% +mechanism it might be a new way of +immunizing patients whatever it is okay + + align:start position:0% +immunizing patients whatever it is okay + + + align:start position:0% +immunizing patients whatever it is okay +and then she's going to document + + align:start position:0% +and then she's going to document + + + align:start position:0% +and then she's going to document +everything that's going on so she's + + align:start position:0% +everything that's going on so she's + + + align:start position:0% +everything that's going on so she's +going to document not only the + + align:start position:0% +going to document not only the + + + align:start position:0% +going to document not only the +measurement that we have articulated in + + align:start position:0% +measurement that we have articulated in + + + align:start position:0% +measurement that we have articulated in +the plan right but she's also going to + + align:start position:0% +the plan right but she's also going to + + + align:start position:0% +the plan right but she's also going to +document anything out of the ordinary + + align:start position:0% +document anything out of the ordinary + + + align:start position:0% +document anything out of the ordinary +anything that she's learning that she + + align:start position:0% +anything that she's learning that she + + + align:start position:0% +anything that she's learning that she +hadn't predicted anything that is + + align:start position:0% +hadn't predicted anything that is + + + align:start position:0% +hadn't predicted anything that is +against the assumptions that she made or + + align:start position:0% +against the assumptions that she made or + + + align:start position:0% +against the assumptions that she made or +that the team made together so she's + + align:start position:0% +that the team made together so she's + + + align:start position:0% +that the team made together so she's +going to capture that information during + + align:start position:0% +going to capture that information during + + + align:start position:0% +going to capture that information during +the due phase right now the study phase + + align:start position:0% +the due phase right now the study phase + + + align:start position:0% +the due phase right now the study phase +is where we start to look at what we + + align:start position:0% +is where we start to look at what we + + + align:start position:0% +is where we start to look at what we +learned and the study phase builds upon + + align:start position:0% +learned and the study phase builds upon + + + align:start position:0% +learned and the study phase builds upon +a very important part of the plan now + + align:start position:0% +a very important part of the plan now + + + align:start position:0% +a very important part of the plan now +the second bullet in the plan there it + + align:start position:0% +the second bullet in the plan there it + + + align:start position:0% +the second bullet in the plan there it +says make + + align:start position:0% +says make + + + align:start position:0% +says make +predictions nurse Judy and her quality + + align:start position:0% +predictions nurse Judy and her quality + + + align:start position:0% +predictions nurse Judy and her quality +improvement team when they're planning + + align:start position:0% +improvement team when they're planning + + + align:start position:0% +improvement team when they're planning +what they're going to do on Monday + + align:start position:0% +what they're going to do on Monday + + + align:start position:0% +what they're going to do on Monday +morning they're going to make a + + align:start position:0% +morning they're going to make a + + + align:start position:0% +morning they're going to make a +prediction about how performance will + + align:start position:0% +prediction about how performance will + + + align:start position:0% +prediction about how performance will +change for those 10 patients okay + + align:start position:0% +change for those 10 patients okay + + + align:start position:0% +change for those 10 patients okay +and they're going to write that out all + + align:start position:0% +and they're going to write that out all + + + align:start position:0% +and they're going to write that out all +10 patients are going to get their + + align:start position:0% +10 patients are going to get their + + + align:start position:0% +10 patients are going to get their +immunization today as opposed to the + + align:start position:0% +immunization today as opposed to the + + + align:start position:0% +immunization today as opposed to the +five who got them last week okay they're + + align:start position:0% +five who got them last week okay they're + + + align:start position:0% +five who got them last week okay they're +going to write out that prediction when + + align:start position:0% +going to write out that prediction when + + + align:start position:0% +going to write out that prediction when +it comes to the study phase they're + + align:start position:0% +it comes to the study phase they're + + + align:start position:0% +it comes to the study phase they're +going to compare what did we learn that + + align:start position:0% +going to compare what did we learn that + + + align:start position:0% +going to compare what did we learn that +we didn't anticipate and did we achieve + + align:start position:0% +we didn't anticipate and did we achieve + + + align:start position:0% +we didn't anticipate and did we achieve +what we predicted we would okay and if + + align:start position:0% +what we predicted we would okay and if + + + align:start position:0% +what we predicted we would okay and if +not why + + align:start position:0% +not why + + + align:start position:0% +not why +not right we're going to lay all that + + align:start position:0% +not right we're going to lay all that + + + align:start position:0% +not right we're going to lay all that +out and ask those questions and have + + align:start position:0% +out and ask those questions and have + + + align:start position:0% +out and ask those questions and have +that + + align:start position:0% +that + + + align:start position:0% +that +conversation Monday afternoon during our + + align:start position:0% +conversation Monday afternoon during our + + + align:start position:0% +conversation Monday afternoon during our +lunch break + + align:start position:0% +lunch break + + + align:start position:0% +lunch break +okay and then we're going to make a + + align:start position:0% +okay and then we're going to make a + + + align:start position:0% +okay and then we're going to make a +decision about what to do next if that + + align:start position:0% +decision about what to do next if that + + + align:start position:0% +decision about what to do next if that +change idea was successful we might + + align:start position:0% +change idea was successful we might + + + align:start position:0% +change idea was successful we might +decide you know that's great it worked + + align:start position:0% +decide you know that's great it worked + + + align:start position:0% +decide you know that's great it worked +really well we want to try it again but + + align:start position:0% +really well we want to try it again but + + + align:start position:0% +really well we want to try it again but +on a larger scale instead of 10 patients + + align:start position:0% +on a larger scale instead of 10 patients + + + align:start position:0% +on a larger scale instead of 10 patients +we're going to scale it up to 50 + + align:start position:0% +we're going to scale it up to 50 + + + align:start position:0% +we're going to scale it up to 50 +patients okay so that's what we're going + + align:start position:0% +patients okay so that's what we're going + + + align:start position:0% +patients okay so that's what we're going +to do during the action phase if it + + align:start position:0% +to do during the action phase if it + + + align:start position:0% +to do during the action phase if it +works marginally well but we think we + + align:start position:0% +works marginally well but we think we + + + align:start position:0% +works marginally well but we think we +learned how to do it better then we + + align:start position:0% +learned how to do it better then we + + + align:start position:0% +learned how to do it better then we +might say you you know instead of + + align:start position:0% +might say you you know instead of + + + align:start position:0% +might say you you know instead of +adopting this we're going to adapt it + + align:start position:0% +adopting this we're going to adapt it + + + align:start position:0% +adopting this we're going to adapt it +we're going to run it again on 10 + + align:start position:0% +we're going to run it again on 10 + + + align:start position:0% +we're going to run it again on 10 +patients on Tuesday morning but with + + align:start position:0% +patients on Tuesday morning but with + + + align:start position:0% +patients on Tuesday morning but with +this slight + + align:start position:0% +this slight + + + align:start position:0% +this slight +alteration right because we learned + + align:start position:0% +alteration right because we learned + + + align:start position:0% +alteration right because we learned +something during that study phase about + + align:start position:0% +something during that study phase about + + + align:start position:0% +something during that study phase about +what worked and what didn't work with + + align:start position:0% +what worked and what didn't work with + + + align:start position:0% +what worked and what didn't work with +the first 10 + + align:start position:0% +the first 10 + + + align:start position:0% +the first 10 +patients + + align:start position:0% +patients + + + align:start position:0% +patients +okay or it might be a colossal failure + + align:start position:0% +okay or it might be a colossal failure + + + align:start position:0% +okay or it might be a colossal failure +and that's totally fine too that's + + align:start position:0% +and that's totally fine too that's + + + align:start position:0% +and that's totally fine too that's +absolutely a fine thing so if it failed + + align:start position:0% +absolutely a fine thing so if it failed + + + align:start position:0% +absolutely a fine thing so if it failed +then we want to talk about that we want + + align:start position:0% +then we want to talk about that we want + + + align:start position:0% +then we want to talk about that we want +to embrace that and then we'll say okay + + align:start position:0% +to embrace that and then we'll say okay + + + align:start position:0% +to embrace that and then we'll say okay +well why did it fail what does that tell + + align:start position:0% +well why did it fail what does that tell + + + align:start position:0% +well why did it fail what does that tell +us about how we should change our + + align:start position:0% +us about how we should change our + + + align:start position:0% +us about how we should change our +assumptions how should we change our + + align:start position:0% +assumptions how should we change our + + + align:start position:0% +assumptions how should we change our +Theory and what different idea would we + + align:start position:0% +Theory and what different idea would we + + + align:start position:0% +Theory and what different idea would we +like to change or like to test as a + + align:start position:0% +like to change or like to test as a + + + align:start position:0% +like to change or like to test as a +result okay so what different idea do we + + align:start position:0% +result okay so what different idea do we + + + align:start position:0% +result okay so what different idea do we +want to test as a result right and then + + align:start position:0% +want to test as a result right and then + + + align:start position:0% +want to test as a result right and then +we're going to do that on Tuesday make + + align:start position:0% +we're going to do that on Tuesday make + + + align:start position:0% +we're going to do that on Tuesday make +some new predictions and make a new plan + + align:start position:0% +some new predictions and make a new plan + + + align:start position:0% +some new predictions and make a new plan +so we can do all of that through the + + align:start position:0% +so we can do all of that through the + + + align:start position:0% +so we can do all of that through the +pdsa cycle okay all that's very very + + align:start position:0% +pdsa cycle okay all that's very very + + + align:start position:0% +pdsa cycle okay all that's very very +specific this has been done for 70 years + + align:start position:0% +specific this has been done for 70 years + + + align:start position:0% +specific this has been done for 70 years +in manufacturing right Toyota runs on on + + align:start position:0% +in manufacturing right Toyota runs on on + + + align:start position:0% +in manufacturing right Toyota runs on on +average A th000 pdsa Cycles a day in + + align:start position:0% +average A th000 pdsa Cycles a day in + + + align:start position:0% +average A th000 pdsa Cycles a day in +their manufacturing plants around the + + align:start position:0% +their manufacturing plants around the + + + align:start position:0% +their manufacturing plants around the +world okay in healthcare we're still + + align:start position:0% +world okay in healthcare we're still + + + align:start position:0% +world okay in healthcare we're still +learning how to do this and we have some + + align:start position:0% +learning how to do this and we have some + + + align:start position:0% +learning how to do this and we have some +special considerations right we're not + + align:start position:0% +special considerations right we're not + + + align:start position:0% +special considerations right we're not +building cars we're working with + + align:start position:0% +building cars we're working with + + + align:start position:0% +building cars we're working with +patients so we always need to make sure + + align:start position:0% +patients so we always need to make sure + + + align:start position:0% +patients so we always need to make sure +that we're not doing things that could + + align:start position:0% +that we're not doing things that could + + + align:start position:0% +that we're not doing things that could +harm patients but there's lots that we + + align:start position:0% +harm patients but there's lots that we + + + align:start position:0% +harm patients but there's lots that we +can do in terms of changing Data Systems + + align:start position:0% +can do in terms of changing Data Systems + + + align:start position:0% +can do in terms of changing Data Systems +changing the flow of a clinic changing + + align:start position:0% +changing the flow of a clinic changing + + + align:start position:0% +changing the flow of a clinic changing +the order in which we do certain things + + align:start position:0% +the order in which we do certain things + + + align:start position:0% +the order in which we do certain things +that's safe but still needs to be tested + + align:start position:0% +that's safe but still needs to be tested + + + align:start position:0% +that's safe but still needs to be tested +to understand if it will impact the + + align:start position:0% +to understand if it will impact the + + + align:start position:0% +to understand if it will impact the +reliability of care that we're + + align:start position:0% +reliability of care that we're + + + align:start position:0% +reliability of care that we're +providing so that's that's the pdsa + + align:start position:0% +providing so that's that's the pdsa + + + align:start position:0% +providing so that's that's the pdsa +cycle and that's the second half of the + + align:start position:0% +cycle and that's the second half of the + + + align:start position:0% +cycle and that's the second half of the +model for improvement + + align:start position:0% +model for improvement + + + align:start position:0% +model for improvement +okay + + align:start position:0% +okay + + + align:start position:0% +okay +okay all right so my second challenge to + + align:start position:0% +okay all right so my second challenge to + + + align:start position:0% +okay all right so my second challenge to +you is to develop a pdsa with your team + + align:start position:0% +you is to develop a pdsa with your team + + + align:start position:0% +you is to develop a pdsa with your team +right it could be a pdsa to see if + + align:start position:0% +right it could be a pdsa to see if + + + align:start position:0% +right it could be a pdsa to see if +you've got an idea that can improve + + align:start position:0% +you've got an idea that can improve + + + align:start position:0% +you've got an idea that can improve +something or it could be a pdsa simply + + align:start position:0% +something or it could be a pdsa simply + + + align:start position:0% +something or it could be a pdsa simply +to learn about the system that you're + + align:start position:0% +to learn about the system that you're + + + align:start position:0% +to learn about the system that you're +trying to to improve okay but I would + + align:start position:0% +trying to to improve okay but I would + + + align:start position:0% +trying to to improve okay but I would +challenge you with your project teams as + + align:start position:0% +challenge you with your project teams as + + + align:start position:0% +challenge you with your project teams as +you as you start to think about things + + align:start position:0% +you as you start to think about things + + + align:start position:0% +you as you start to think about things +how could we use this this methodology + + align:start position:0% +how could we use this this methodology + + + align:start position:0% +how could we use this this methodology +how could we use a pdsa cycle to learn + + align:start position:0% +how could we use a pdsa cycle to learn + + + align:start position:0% +how could we use a pdsa cycle to learn +about how to improve the data systems + + align:start position:0% +about how to improve the data systems + + + align:start position:0% +about how to improve the data systems +that we're working + + align:start position:0% +that we're working + + + align:start position:0% +that we're working +on all right here's a potential form you + + align:start position:0% +on all right here's a potential form you + + + align:start position:0% +on all right here's a potential form you +can use I can give this to you if you + + align:start position:0% +can use I can give this to you if you + + + align:start position:0% +can use I can give this to you if you +want of how you can write things down + + align:start position:0% +want of how you can write things down + + + align:start position:0% +want of how you can write things down +and have a data capture tool for each of + + align:start position:0% +and have a data capture tool for each of + + + align:start position:0% +and have a data capture tool for each of +individual pdsa + + align:start position:0% +individual pdsa + + + align:start position:0% +individual pdsa +cycle Okay and like I said you want to + + align:start position:0% +cycle Okay and like I said you want to + + + align:start position:0% +cycle Okay and like I said you want to +slowly build up as you go right actually + + align:start position:0% +slowly build up as you go right actually + + + align:start position:0% +slowly build up as you go right actually +rapidly but as fast as you can right + + align:start position:0% +rapidly but as fast as you can right + + + align:start position:0% +rapidly but as fast as you can right +some hospitals will do three four five + + align:start position:0% +some hospitals will do three four five + + + align:start position:0% +some hospitals will do three four five +pdsa a week on an individual process + + align:start position:0% +pdsa a week on an individual process + + + align:start position:0% +pdsa a week on an individual process +right maybe 50 across a whole hospital + + align:start position:0% +right maybe 50 across a whole hospital + + + align:start position:0% +right maybe 50 across a whole hospital +it's great so here's uh here's Julie + + align:start position:0% +it's great so here's uh here's Julie + + + align:start position:0% +it's great so here's uh here's Julie +Julie is a nurse that I had the + + align:start position:0% +Julie is a nurse that I had the + + + align:start position:0% +Julie is a nurse that I had the +opportunity to work with in South Africa + + align:start position:0% +opportunity to work with in South Africa + + + align:start position:0% +opportunity to work with in South Africa +and I wanted to give you a real life + + align:start position:0% +and I wanted to give you a real life + + + align:start position:0% +and I wanted to give you a real life +story of how we could use + + align:start position:0% +story of how we could use + + + align:start position:0% +story of how we could use +pdsa okay so Julie uh is a fantastic + + align:start position:0% +pdsa okay so Julie uh is a fantastic + + + align:start position:0% +pdsa okay so Julie uh is a fantastic +nurse she's a HIV nurse and she was uh + + align:start position:0% +nurse she's a HIV nurse and she was uh + + + align:start position:0% +nurse she's a HIV nurse and she was uh +focused on uh uh on voluntary counseling + + align:start position:0% +focused on uh uh on voluntary counseling + + + align:start position:0% +focused on uh uh on voluntary counseling +and testing of HIV Services right Julie + + align:start position:0% +and testing of HIV Services right Julie + + + align:start position:0% +and testing of HIV Services right Julie +is a a tremendous tremendously hard + + align:start position:0% +is a a tremendous tremendously hard + + + align:start position:0% +is a a tremendous tremendously hard +worker really devoted to her community + + align:start position:0% +worker really devoted to her community + + + align:start position:0% +worker really devoted to her community +and as uh uh as we started to increase + + align:start position:0% +and as uh uh as we started to increase + + + align:start position:0% +and as uh uh as we started to increase +uh VCT we started to increase the total + + align:start position:0% +uh VCT we started to increase the total + + + align:start position:0% +uh VCT we started to increase the total +number of people who are testing H + + align:start position:0% +number of people who are testing H + + + align:start position:0% +number of people who are testing H +positive uh we we had perfect + + align:start position:0% +positive uh we we had perfect + + + align:start position:0% +positive uh we we had perfect +performance on testing but that led to a + + align:start position:0% +performance on testing but that led to a + + + align:start position:0% +performance on testing but that led to a +huge influx of new patients who needed + + align:start position:0% +huge influx of new patients who needed + + + align:start position:0% +huge influx of new patients who needed +treatment unanticipated consequence of + + align:start position:0% +treatment unanticipated consequence of + + + align:start position:0% +treatment unanticipated consequence of +improved care right nothing wrong with + + align:start position:0% +improved care right nothing wrong with + + + align:start position:0% +improved care right nothing wrong with +that that's a good problem to have but + + align:start position:0% +that that's a good problem to have but + + + align:start position:0% +that that's a good problem to have but +now we're overwhelming our chronic care + + align:start position:0% +now we're overwhelming our chronic care + + + align:start position:0% +now we're overwhelming our chronic care +abilities and Julie was working at at a + + align:start position:0% +abilities and Julie was working at at a + + + align:start position:0% +abilities and Julie was working at at a +hospital where they were starting to see + + align:start position:0% +hospital where they were starting to see + + + align:start position:0% +hospital where they were starting to see +upwards of 300 patients a day just to + + align:start position:0% +upwards of 300 patients a day just to + + + align:start position:0% +upwards of 300 patients a day just to +provide chronic care let alone new + + align:start position:0% +provide chronic care let alone new + + + align:start position:0% +provide chronic care let alone new +patients who are coming in the door okay + + align:start position:0% +patients who are coming in the door okay + + + align:start position:0% +patients who are coming in the door okay +so we had this problem where we had so + + align:start position:0% +so we had this problem where we had so + + + align:start position:0% +so we had this problem where we had so +much chronic care going on that we were + + align:start position:0% +much chronic care going on that we were + + + align:start position:0% +much chronic care going on that we were +running out of resources to provide care + + align:start position:0% +running out of resources to provide care + + + align:start position:0% +running out of resources to provide care +to new patients and there we were + + align:start position:0% +to new patients and there we were + + + align:start position:0% +to new patients and there we were +starting to build build up a queue we + + align:start position:0% +starting to build build up a queue we + + + align:start position:0% +starting to build build up a queue we +were getting a line of people who were + + align:start position:0% +were getting a line of people who were + + + align:start position:0% +were getting a line of people who were +waiting to get on to treatment so this + + align:start position:0% +waiting to get on to treatment so this + + + align:start position:0% +waiting to get on to treatment so this +was uh this was quite a while ago and we + + align:start position:0% +was uh this was quite a while ago and we + + + align:start position:0% +was uh this was quite a while ago and we +thought well what could we do about this + + align:start position:0% +thought well what could we do about this + + + align:start position:0% +thought well what could we do about this +and Julie said well you know we've got + + align:start position:0% +and Julie said well you know we've got + + + align:start position:0% +and Julie said well you know we've got +all these clinics that refer patients to + + align:start position:0% +all these clinics that refer patients to + + + align:start position:0% +all these clinics that refer patients to +us for care what if we started doing + + align:start position:0% +us for care what if we started doing + + + align:start position:0% +us for care what if we started doing +chronic Care at the + + align:start position:0% +chronic Care at the + + + align:start position:0% +chronic Care at the +clinics okay what if we did chronic Care + + align:start position:0% +clinics okay what if we did chronic Care + + + align:start position:0% +clinics okay what if we did chronic Care +at the clinics instead of here at the + + align:start position:0% +at the clinics instead of here at the + + + align:start position:0% +at the clinics instead of here at the +hospital that could free up space for us + + align:start position:0% +hospital that could free up space for us + + + align:start position:0% +hospital that could free up space for us +to initiate new patients on to treatment + + align:start position:0% +to initiate new patients on to treatment + + + align:start position:0% +to initiate new patients on to treatment +so that's a that's a great idea that's a + + align:start position:0% +so that's a that's a great idea that's a + + + align:start position:0% +so that's a that's a great idea that's a +fantastic idea how are we going to do + + align:start position:0% +fantastic idea how are we going to do + + + align:start position:0% +fantastic idea how are we going to do +that no one had ever done that in this + + align:start position:0% +that no one had ever done that in this + + + align:start position:0% +that no one had ever done that in this +particular particular District before so + + align:start position:0% +particular particular District before so + + + align:start position:0% +particular particular District before so +how are we going to do that nobody knows + + align:start position:0% +how are we going to do that nobody knows + + + align:start position:0% +how are we going to do that nobody knows +how so we said well let's let's plan a + + align:start position:0% +how so we said well let's let's plan a + + + align:start position:0% +how so we said well let's let's plan a +pdsa we came up with a seven-step plan + + align:start position:0% +pdsa we came up with a seven-step plan + + + align:start position:0% +pdsa we came up with a seven-step plan +it involved things like making sure we + + align:start position:0% +it involved things like making sure we + + + align:start position:0% +it involved things like making sure we +had the drugs prepackaged and sent ahead + + align:start position:0% +had the drugs prepackaged and sent ahead + + + align:start position:0% +had the drugs prepackaged and sent ahead +of time to the clinic notification of + + align:start position:0% +of time to the clinic notification of + + + align:start position:0% +of time to the clinic notification of +the patients make sure that they were + + align:start position:0% +the patients make sure that they were + + + align:start position:0% +the patients make sure that they were +ready and willing to accept treatment at + + align:start position:0% +ready and willing to accept treatment at + + + align:start position:0% +ready and willing to accept treatment at +a clinic instead of at the hospital + + align:start position:0% +a clinic instead of at the hospital + + + align:start position:0% +a clinic instead of at the hospital +there's all there's seven steps that we + + align:start position:0% +there's all there's seven steps that we + + + align:start position:0% +there's all there's seven steps that we +had in place and we said okay all right + + align:start position:0% +had in place and we said okay all right + + + align:start position:0% +had in place and we said okay all right +Julia we're ready on Monday we're going + + align:start position:0% +Julia we're ready on Monday we're going + + + align:start position:0% +Julia we're ready on Monday we're going +to try it with two patients and so we + + align:start position:0% +to try it with two patients and so we + + + align:start position:0% +to try it with two patients and so we +did we had two patients who were willing + + align:start position:0% +did we had two patients who were willing + + + align:start position:0% +did we had two patients who were willing +participants and they said yes we would + + align:start position:0% +participants and they said yes we would + + + align:start position:0% +participants and they said yes we would +like to try to get our treatment at our + + align:start position:0% +like to try to get our treatment at our + + + align:start position:0% +like to try to get our treatment at our +local Clinic instead of at the hospital + + align:start position:0% +local Clinic instead of at the hospital + + + align:start position:0% +local Clinic instead of at the hospital +this month so those two patients + + align:start position:0% +this month so those two patients + + + align:start position:0% +this month so those two patients +went and wouldn't you know it only one + + align:start position:0% +went and wouldn't you know it only one + + + align:start position:0% +went and wouldn't you know it only one +of them got their + + align:start position:0% +of them got their + + + align:start position:0% +of them got their +medication so we predicted both of them + + align:start position:0% +medication so we predicted both of them + + + align:start position:0% +medication so we predicted both of them +would get it and only one did so we said + + align:start position:0% +would get it and only one did so we said + + + align:start position:0% +would get it and only one did so we said +what happened and we did during the + + align:start position:0% +what happened and we did during the + + + align:start position:0% +what happened and we did during the +study phase We examined the situation we + + align:start position:0% +study phase We examined the situation we + + + align:start position:0% +study phase We examined the situation we +realized that we had missed a step we + + align:start position:0% +realized that we had missed a step we + + + align:start position:0% +realized that we had missed a step we +had missed a step in connecting the + + align:start position:0% +had missed a step in connecting the + + + align:start position:0% +had missed a step in connecting the +pharmacy with the clinic okay and so it + + align:start position:0% +pharmacy with the clinic okay and so it + + + align:start position:0% +pharmacy with the clinic okay and so it +was a failure now it was a really good + + align:start position:0% +was a failure now it was a really good + + + align:start position:0% +was a failure now it was a really good +idea but if we had gone to full scale + + align:start position:0% +idea but if we had gone to full scale + + + align:start position:0% +idea but if we had gone to full scale +right away and we had had a 50% failure + + align:start position:0% +right away and we had had a 50% failure + + + align:start position:0% +right away and we had had a 50% failure +rate that would have been catastrophic + + align:start position:0% +rate that would have been catastrophic + + + align:start position:0% +rate that would have been catastrophic +for our HIV patients because it was two + + align:start position:0% +for our HIV patients because it was two + + + align:start position:0% +for our HIV patients because it was two +patients it was real easy to just call + + align:start position:0% +patients it was real easy to just call + + + align:start position:0% +patients it was real easy to just call +that patient up and say hey come to the + + align:start position:0% +that patient up and say hey come to the + + + align:start position:0% +that patient up and say hey come to the +hospital tomorrow we'll pay for the taxi + + align:start position:0% +hospital tomorrow we'll pay for the taxi + + + align:start position:0% +hospital tomorrow we'll pay for the taxi +fee and uh and we'll get you your + + align:start position:0% +fee and uh and we'll get you your + + + align:start position:0% +fee and uh and we'll get you your +medication now we learned what happened + + align:start position:0% +medication now we learned what happened + + + align:start position:0% +medication now we learned what happened +we fixed that we went from a seven step + + align:start position:0% +we fixed that we went from a seven step + + + align:start position:0% +we fixed that we went from a seven step +to an E step and the following week we + + align:start position:0% +to an E step and the following week we + + + align:start position:0% +to an E step and the following week we +down referred five patients okay + + align:start position:0% +down referred five patients okay + + + align:start position:0% +down referred five patients okay +five patients worked great all five + + align:start position:0% +five patients worked great all five + + + align:start position:0% +five patients worked great all five +patients got their medication we felt + + align:start position:0% +patients got their medication we felt + + + align:start position:0% +patients got their medication we felt +good about that we uh learned a few more + + align:start position:0% +good about that we uh learned a few more + + + align:start position:0% +good about that we uh learned a few more +things so the next week we down referred + + align:start position:0% +things so the next week we down referred + + + align:start position:0% +things so the next week we down referred +15 right worked perfect no problems the + + align:start position:0% +15 right worked perfect no problems the + + + align:start position:0% +15 right worked perfect no problems the +next week we down referred 50 right it + + align:start position:0% +next week we down referred 50 right it + + + align:start position:0% +next week we down referred 50 right it +took us five weeks to go from zero to + + align:start position:0% +took us five weeks to go from zero to + + + align:start position:0% +took us five weeks to go from zero to +down referring everybody in that + + align:start position:0% +down referring everybody in that + + + align:start position:0% +down referring everybody in that +particular catchman area to their local + + align:start position:0% +particular catchman area to their local + + + align:start position:0% +particular catchman area to their local +Clinic okay so but we were able to do + + align:start position:0% +Clinic okay so but we were able to do + + + align:start position:0% +Clinic okay so but we were able to do +that using the pdsa cycle and learning + + align:start position:0% +that using the pdsa cycle and learning + + + align:start position:0% +that using the pdsa cycle and learning +about what the limits were of of our + + align:start position:0% +about what the limits were of of our + + + align:start position:0% +about what the limits were of of our +implementation so it's a good example of + + align:start position:0% +implementation so it's a good example of + + + align:start position:0% +implementation so it's a good example of +of how you can scale up and learn + + align:start position:0% +of how you can scale up and learn + + + align:start position:0% +of how you can scale up and learn +quickly about uh uh Improvement in your + + align:start position:0% +quickly about uh uh Improvement in your + + + align:start position:0% +quickly about uh uh Improvement in your +system all right + + align:start position:0% +system all right + + + align:start position:0% +system all right +so what's the lesson there you also have + + align:start position:0% +so what's the lesson there you also have + + + align:start position:0% +so what's the lesson there you also have +to think ahead okay because with scale + + align:start position:0% +to think ahead okay because with scale + + + align:start position:0% +to think ahead okay because with scale +comes new problems unanticipated + + align:start position:0% +comes new problems unanticipated + + + align:start position:0% +comes new problems unanticipated +problems when you're working with one + + align:start position:0% +problems when you're working with one + + + align:start position:0% +problems when you're working with one +two five patients yeah pretty easy you + + align:start position:0% +two five patients yeah pretty easy you + + + align:start position:0% +two five patients yeah pretty easy you +can call them up on the phone you can + + align:start position:0% +can call them up on the phone you can + + + align:start position:0% +can call them up on the phone you can +get them on a taxi when you start + + align:start position:0% +get them on a taxi when you start + + + align:start position:0% +get them on a taxi when you start +working with 50 100 a th000 10,000 you + + align:start position:0% +working with 50 100 a th000 10,000 you + + + align:start position:0% +working with 50 100 a th000 10,000 you +have new problems so if you're using the + + align:start position:0% +have new problems so if you're using the + + + align:start position:0% +have new problems so if you're using the +pdsa cycle you always want to be + + align:start position:0% +pdsa cycle you always want to be + + + align:start position:0% +pdsa cycle you always want to be +thinking two three steps ahead when I + + align:start position:0% +thinking two three steps ahead when I + + + align:start position:0% +thinking two three steps ahead when I +scale this up what what's going to + + align:start position:0% +scale this up what what's going to + + + align:start position:0% +scale this up what what's going to +happen right is there going to be a + + align:start position:0% +happen right is there going to be a + + + align:start position:0% +happen right is there going to be a +failure here associated with scale + + align:start position:0% +failure here associated with scale + + + align:start position:0% +failure here associated with scale +that's going to introduce something that + + align:start position:0% +that's going to introduce something that + + + align:start position:0% +that's going to introduce something that +we're not anticipating right if you can + + align:start position:0% +we're not anticipating right if you can + + + align:start position:0% +we're not anticipating right if you can +do that early in the process you can + + align:start position:0% +do that early in the process you can + + + align:start position:0% +do that early in the process you can +start to plan for that make adjustments + + align:start position:0% +start to plan for that make adjustments + + + align:start position:0% +start to plan for that make adjustments +to the change + + align:start position:0% +to the change + + + align:start position:0% +to the change +idea all right so knowing when to + + align:start position:0% +idea all right so knowing when to + + + align:start position:0% +idea all right so knowing when to +implement A Change Is is CRI critically + + align:start position:0% +implement A Change Is is CRI critically + + + align:start position:0% +implement A Change Is is CRI critically +important + + align:start position:0% +important + + + align:start position:0% +important +okay there's times where you're + + align:start position:0% +okay there's times where you're + + + align:start position:0% +okay there's times where you're +developing change times where you're + + align:start position:0% +developing change times where you're + + + align:start position:0% +developing change times where you're +testing change and times where you're + + align:start position:0% +testing change and times where you're + + + align:start position:0% +testing change and times where you're +implementing change implementing change + + align:start position:0% +implementing change implementing change + + + align:start position:0% +implementing change implementing change +is different than testing you have a + + align:start position:0% +is different than testing you have a + + + align:start position:0% +is different than testing you have a +great idea you're innovating something + + align:start position:0% +great idea you're innovating something + + + align:start position:0% +great idea you're innovating something +you're testing it out you think this is + + align:start position:0% +you're testing it out you think this is + + + align:start position:0% +you're testing it out you think this is +fantastic this down referral process at + + align:start position:0% +fantastic this down referral process at + + + align:start position:0% +fantastic this down referral process at +a shi Hospital fantastic right great + + align:start position:0% +a shi Hospital fantastic right great + + + align:start position:0% +a shi Hospital fantastic right great +testing now we're ready to implement now + + align:start position:0% +testing now we're ready to implement now + + + align:start position:0% +testing now we're ready to implement now +what are we talking about we're talking + + align:start position:0% +what are we talking about we're talking + + + align:start position:0% +what are we talking about we're talking +about changing policy we're talking + + align:start position:0% +about changing policy we're talking + + + align:start position:0% +about changing policy we're talking +about rewriting job descriptions right + + align:start position:0% +about rewriting job descriptions right + + + align:start position:0% +about rewriting job descriptions right +we're talking about developing new + + align:start position:0% +we're talking about developing new + + + align:start position:0% +we're talking about developing new +training curriculum we're talking about + + align:start position:0% +training curriculum we're talking about + + + align:start position:0% +training curriculum we're talking about +re-education of the workforce that + + align:start position:0% +re-education of the workforce that + + + align:start position:0% +re-education of the workforce that +exists right all of that which is not in + + align:start position:0% +exists right all of that which is not in + + + align:start position:0% +exists right all of that which is not in +the Mainstay delivery of care but is in + + align:start position:0% +the Mainstay delivery of care but is in + + + align:start position:0% +the Mainstay delivery of care but is in +the support processes is in the redesign + + align:start position:0% +the support processes is in the redesign + + + align:start position:0% +the support processes is in the redesign +processes implementation is a whole + + align:start position:0% +processes implementation is a whole + + + align:start position:0% +processes implementation is a whole +different animal so when you get ready + + align:start position:0% +different animal so when you get ready + + + align:start position:0% +different animal so when you get ready +to take that new idea to implementation + + align:start position:0% +to take that new idea to implementation + + + align:start position:0% +to take that new idea to implementation +you have to think about all of those + + align:start position:0% +you have to think about all of those + + + align:start position:0% +you have to think about all of those +different things that are going to come + + align:start position:0% +different things that are going to come + + + align:start position:0% +different things that are going to come +together to make sure that that change + + align:start position:0% +together to make sure that that change + + + align:start position:0% +together to make sure that that change +idea continues to be a success one of + + align:start position:0% +idea continues to be a success one of + + + align:start position:0% +idea continues to be a success one of +the failures of lots of projects is they + + align:start position:0% +the failures of lots of projects is they + + + align:start position:0% +the failures of lots of projects is they +have a great idea they go in they try it + + align:start position:0% +have a great idea they go in they try it + + + align:start position:0% +have a great idea they go in they try it +out they start using it everywhere and + + align:start position:0% +out they start using it everywhere and + + + align:start position:0% +out they start using it everywhere and +then what happens the money runs out + + align:start position:0% +then what happens the money runs out + + + align:start position:0% +then what happens the money runs out +because the funders is moving on to a + + align:start position:0% +because the funders is moving on to a + + + align:start position:0% +because the funders is moving on to a +new cycle and nobody bothered to change + + align:start position:0% +new cycle and nobody bothered to change + + + align:start position:0% +new cycle and nobody bothered to change +the job description nobody bother to + + align:start position:0% +the job description nobody bother to + + + align:start position:0% +the job description nobody bother to +rewrite the policy that new group of + + align:start position:0% +rewrite the policy that new group of + + + align:start position:0% +rewrite the policy that new group of +doctors rotated in from a different + + align:start position:0% +doctors rotated in from a different + + + align:start position:0% +doctors rotated in from a different +place and didn't know anything about it + + align:start position:0% +place and didn't know anything about it + + + align:start position:0% +place and didn't know anything about it +and suddenly that wonderful change is + + align:start position:0% +and suddenly that wonderful change is + + + align:start position:0% +and suddenly that wonderful change is +lost so implementation requires us to + + align:start position:0% +lost so implementation requires us to + + + align:start position:0% +lost so implementation requires us to +pay attention to those details those + + align:start position:0% +pay attention to those details those + + + align:start position:0% +pay attention to those details those +things that we're going to encounter + + align:start position:0% +things that we're going to encounter + + + align:start position:0% +things that we're going to encounter +particularly in resource constrainted + + align:start position:0% +particularly in resource constrainted + + + align:start position:0% +particularly in resource constrainted +environments where where we we uh have + + align:start position:0% +environments where where we we uh have + + + align:start position:0% +environments where where we we uh have +turnover okay so here's a this is from + + align:start position:0% +turnover okay so here's a this is from + + + align:start position:0% +turnover okay so here's a this is from +the Improvement guide as well uh it's a + + align:start position:0% +the Improvement guide as well uh it's a + + + align:start position:0% +the Improvement guide as well uh it's a +great little table that I would refer + + align:start position:0% +great little table that I would refer + + + align:start position:0% +great little table that I would refer +you to when you start thinking about if + + align:start position:0% +you to when you start thinking about if + + + align:start position:0% +you to when you start thinking about if +you wanted to implement an idea when you + + align:start position:0% +you wanted to implement an idea when you + + + align:start position:0% +you wanted to implement an idea when you +should do so there are three key factors + + align:start position:0% +should do so there are three key factors + + + align:start position:0% +should do so there are three key factors +one are people ready for + + align:start position:0% +one are people ready for + + + align:start position:0% +one are people ready for +change hugely important right that's the + + align:start position:0% +change hugely important right that's the + + + align:start position:0% +change hugely important right that's the +psychology component when we talk about + + align:start position:0% +psychology component when we talk about + + + align:start position:0% +psychology component when we talk about +profound knowledge are they resistant + + align:start position:0% +profound knowledge are they resistant + + + align:start position:0% +profound knowledge are they resistant +are they indifferent or are they ready + + align:start position:0% +are they indifferent or are they ready + + + align:start position:0% +are they indifferent or are they ready +right if people are not ready you're not + + align:start position:0% +right if people are not ready you're not + + + align:start position:0% +right if people are not ready you're not +ready to + + align:start position:0% +ready to + + + align:start position:0% +ready to +implement if there's any kind of + + align:start position:0% +implement if there's any kind of + + + align:start position:0% +implement if there's any kind of +resistance at all you're still looking + + align:start position:0% +resistance at all you're still looking + + + align:start position:0% +resistance at all you're still looking +at small tests of change one patient two + + align:start position:0% +at small tests of change one patient two + + + align:start position:0% +at small tests of change one patient two +patients one week one day okay do you + + align:start position:0% +patients one week one day okay do you + + + align:start position:0% +patients one week one day okay do you +have confidence do you have a high + + align:start position:0% +have confidence do you have a high + + + align:start position:0% +have confidence do you have a high +degree of belief that this change is + + align:start position:0% +degree of belief that this change is + + + align:start position:0% +degree of belief that this change is +going to be beneficial that it's going + + align:start position:0% +going to be beneficial that it's going + + + align:start position:0% +going to be beneficial that it's going +to be better than the status quo okay if + + align:start position:0% +to be better than the status quo okay if + + + align:start position:0% +to be better than the status quo okay if +you don't more testing is + + align:start position:0% +you don't more testing is + + + align:start position:0% +you don't more testing is +needed and then the Third is what is the + + align:start position:0% +needed and then the Third is what is the + + + align:start position:0% +needed and then the Third is what is the +cost of failure right now this could be + + align:start position:0% +cost of failure right now this could be + + + align:start position:0% +cost of failure right now this could be +Financial cost there could be time cost + + align:start position:0% +Financial cost there could be time cost + + + align:start position:0% +Financial cost there could be time cost +could be human resource cost it could be + + align:start position:0% +could be human resource cost it could be + + + align:start position:0% +could be human resource cost it could be +cost in terms of lives okay so what is + + align:start position:0% +cost in terms of lives okay so what is + + + align:start position:0% +cost in terms of lives okay so what is +the cost of failure right is it high or + + align:start position:0% +the cost of failure right is it high or + + + align:start position:0% +the cost of failure right is it high or +low implementation is only ready when + + align:start position:0% +low implementation is only ready when + + + align:start position:0% +low implementation is only ready when +you have a high degree of belief that + + align:start position:0% +you have a high degree of belief that + + + align:start position:0% +you have a high degree of belief that +what you're doing is better than the + + align:start position:0% +what you're doing is better than the + + + align:start position:0% +what you're doing is better than the +status quo the cost of failure is low + + align:start position:0% +status quo the cost of failure is low + + + align:start position:0% +status quo the cost of failure is low +and people are excited and ready for + + align:start position:0% +and people are excited and ready for + + + align:start position:0% +and people are excited and ready for +change right so it's an assessment of + + align:start position:0% +change right so it's an assessment of + + + align:start position:0% +change right so it's an assessment of +all three of those things is that does + + align:start position:0% +all three of those things is that does + + + align:start position:0% +all three of those things is that does +that make + + align:start position:0% +that make + + + align:start position:0% +that make +sense so as you think about your + + align:start position:0% +sense so as you think about your + + + align:start position:0% +sense so as you think about your +projects you think about what you're + + align:start position:0% +projects you think about what you're + + + align:start position:0% +projects you think about what you're +going to change and what you're going to + + align:start position:0% +going to change and what you're going to + + + align:start position:0% +going to change and what you're going to +take potentially to scale having + + align:start position:0% +take potentially to scale having + + + align:start position:0% +take potentially to scale having +thoughtfulness around these things as + + align:start position:0% +thoughtfulness around these things as + + + align:start position:0% +thoughtfulness around these things as +well as what are the implementation + + align:start position:0% +well as what are the implementation + + + align:start position:0% +well as what are the implementation +issues associated with introducing a new + + align:start position:0% +issues associated with introducing a new + + + align:start position:0% +issues associated with introducing a new +technology a new process a new system + + align:start position:0% +technology a new process a new system + + + align:start position:0% +technology a new process a new system +whatever it is is going to be critically + + align:start position:0% +whatever it is is going to be critically + + + align:start position:0% +whatever it is is going to be critically +important all right I think we'll stop + + align:start position:0% +important all right I think we'll stop + + + align:start position:0% +important all right I think we'll stop +there I threw up the discussion + + align:start position:0% +there I threw up the discussion + + + align:start position:0% +there I threw up the discussion +questions from the syllabus uh but uh + + align:start position:0% +questions from the syllabus uh but uh + + + align:start position:0% +questions from the syllabus uh but uh +stop there question yeah ellot as a \ No newline at end of file diff --git a/JzW4RYICOdA.txt b/JzW4RYICOdA.txt new file mode 100644 index 0000000000000000000000000000000000000000..fb594762043768d835436ee3070c8a57be0b5d7d --- /dev/null +++ b/JzW4RYICOdA.txt @@ -0,0 +1,6227 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT OpenCourseWare continue to + + align:start position:0% +will help MIT OpenCourseWare continue to + + + align:start position:0% +will help MIT OpenCourseWare continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or view additional + + align:start position:0% +to make a donation or view additional + + + align:start position:0% +to make a donation or view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +let's get started + + align:start position:0% + + + + align:start position:0% + +William Klemperer + + align:start position:0% +William Klemperer + + + align:start position:0% +William Klemperer +was was my thesis advisor and he died + + align:start position:0% +was was my thesis advisor and he died + + + align:start position:0% +was was my thesis advisor and he died +yesterday it also happens that the + + align:start position:0% +yesterday it also happens that the + + + align:start position:0% +yesterday it also happens that the +subject of this lecture is the it's + + align:start position:0% +subject of this lecture is the it's + + + align:start position:0% +subject of this lecture is the it's +really the core of what I got from him + + align:start position:0% +really the core of what I got from him + + + align:start position:0% +really the core of what I got from him +he showed me how to evaluate matrix + + align:start position:0% +he showed me how to evaluate matrix + + + align:start position:0% +he showed me how to evaluate matrix +elements of many electron operators + + align:start position:0% +elements of many electron operators + + + align:start position:0% +elements of many electron operators +which is the key to being able to + + align:start position:0% +which is the key to being able to + + + align:start position:0% +which is the key to being able to +interpret not just tabulate electronic + + align:start position:0% +interpret not just tabulate electronic + + + align:start position:0% +interpret not just tabulate electronic +properties of atoms and molecules our + + align:start position:0% +properties of atoms and molecules our + + + align:start position:0% +properties of atoms and molecules our +goal is to be able to reduce the + + align:start position:0% +goal is to be able to reduce the + + + align:start position:0% +goal is to be able to reduce the +complexity of electronic structure which + + align:start position:0% +complexity of electronic structure which + + + align:start position:0% +complexity of electronic structure which +is really complicated the electrons + + align:start position:0% +is really complicated the electrons + + + align:start position:0% +is really complicated the electrons +interact with each other really strongly + + align:start position:0% +interact with each other really strongly + + + align:start position:0% +interact with each other really strongly +and there are a lot of them and it's + + align:start position:0% +and there are a lot of them and it's + + + align:start position:0% +and there are a lot of them and it's +very hard to separate the complexity of + + align:start position:0% +very hard to separate the complexity of + + + align:start position:0% +very hard to separate the complexity of +the many body interactions into things + + align:start position:0% +the many body interactions into things + + + align:start position:0% +the many body interactions into things +that we can put in our head and + + align:start position:0% +that we can put in our head and + + + align:start position:0% +that we can put in our head and +interpret and the whole goal of this + + align:start position:0% +interpret and the whole goal of this + + + align:start position:0% +interpret and the whole goal of this +course is to give you the tools to + + align:start position:0% +course is to give you the tools to + + + align:start position:0% +course is to give you the tools to +interpret complicated phenomena we have + + align:start position:0% +interpret complicated phenomena we have + + + align:start position:0% +interpret complicated phenomena we have +the vibrational problem as a way of + + align:start position:0% +the vibrational problem as a way of + + + align:start position:0% +the vibrational problem as a way of +understanding inter nuclear interactions + + align:start position:0% +understanding inter nuclear interactions + + + align:start position:0% +understanding inter nuclear interactions +nuclear motions we have electronic + + align:start position:0% +nuclear motions we have electronic + + + align:start position:0% +nuclear motions we have electronic +structure and the hydrogen atom as a way + + align:start position:0% +structure and the hydrogen atom as a way + + + align:start position:0% +structure and the hydrogen atom as a way +of understanding what electronic + + align:start position:0% +of understanding what electronic + + + align:start position:0% +of understanding what electronic +structure is and to reduce it to + + align:start position:0% +structure is and to reduce it to + + + align:start position:0% +structure is and to reduce it to +basically the things we learn about + + align:start position:0% +basically the things we learn about + + + align:start position:0% +basically the things we learn about +hydrogen when we go to molecular orbital + + align:start position:0% +hydrogen when we go to molecular orbital + + + align:start position:0% +hydrogen when we go to molecular orbital +Theory we take what we know about atoms + + align:start position:0% +Theory we take what we know about atoms + + + align:start position:0% +Theory we take what we know about atoms +and build a minimally complex complex + + align:start position:0% +and build a minimally complex complex + + + align:start position:0% +and build a minimally complex complex +interpretive picture which is sort of a + + align:start position:0% +interpretive picture which is sort of a + + + align:start position:0% +interpretive picture which is sort of a +framework for understanding + + align:start position:0% +framework for understanding + + + align:start position:0% +framework for understanding +complicated molecular interactions so + + align:start position:0% +complicated molecular interactions so + + + align:start position:0% +complicated molecular interactions so +one of the most important things about + + align:start position:0% +one of the most important things about + + + align:start position:0% +one of the most important things about +understanding electronic structure is + + align:start position:0% +understanding electronic structure is + + + align:start position:0% +understanding electronic structure is +how do we deal with many electron wave + + align:start position:0% +how do we deal with many electron wave + + + align:start position:0% +how do we deal with many electron wave +functions one of the terrible problems + + align:start position:0% +functions one of the terrible problems + + + align:start position:0% +functions one of the terrible problems +is that the electrons are + + align:start position:0% +is that the electrons are + + + align:start position:0% +is that the electrons are +indistinguishable and so we have to + + align:start position:0% +indistinguishable and so we have to + + + align:start position:0% +indistinguishable and so we have to +ensure that the wave functions are anti + + align:start position:0% +ensure that the wave functions are anti + + + align:start position:0% +ensure that the wave functions are anti +symmetric with respect to permutation of + + align:start position:0% +symmetric with respect to permutation of + + + align:start position:0% +symmetric with respect to permutation of +every pair every pair of electrons not + + align:start position:0% +every pair every pair of electrons not + + + align:start position:0% +every pair every pair of electrons not +just two and helium we just dealt with + + align:start position:0% +just two and helium we just dealt with + + + align:start position:0% +just two and helium we just dealt with +two and that wasn't so bad but when we + + align:start position:0% +two and that wasn't so bad but when we + + + align:start position:0% +two and that wasn't so bad but when we +deal with n electrons what we are going + + align:start position:0% +deal with n electrons what we are going + + + align:start position:0% +deal with n electrons what we are going +to discover is that in order to anti + + align:start position:0% +to discover is that in order to anti + + + align:start position:0% +to discover is that in order to anti +symmetrize the wave function we have to + + align:start position:0% +symmetrize the wave function we have to + + + align:start position:0% +symmetrize the wave function we have to +write a determinantal wave function a + + align:start position:0% +write a determinantal wave function a + + + align:start position:0% +write a determinantal wave function a +determinant of orbitals and when you + + align:start position:0% +determinant of orbitals and when you + + + align:start position:0% +determinant of orbitals and when you +expand it and by n determinant you get n + + align:start position:0% +expand it and by n determinant you get n + + + align:start position:0% +expand it and by n determinant you get n +factorial terms and when you calculate + + align:start position:0% +factorial terms and when you calculate + + + align:start position:0% +factorial terms and when you calculate +matrix elements you have n factorial + + align:start position:0% +matrix elements you have n factorial + + + align:start position:0% +matrix elements you have n factorial +squared integrals so you're not going to + + align:start position:0% +squared integrals so you're not going to + + + align:start position:0% +squared integrals so you're not going to +be handling these one at a time and + + align:start position:0% +be handling these one at a time and + + + align:start position:0% +be handling these one at a time and +looking and looking at them lovingly + + align:start position:0% +looking and looking at them lovingly + + + align:start position:0% +looking and looking at them lovingly +you're going to want to be able to take + + align:start position:0% +you're going to want to be able to take + + + align:start position:0% +you're going to want to be able to take +these things and extract what is the + + align:start position:0% +these things and extract what is the + + + align:start position:0% +these things and extract what is the +important thing about the electronic + + align:start position:0% +important thing about the electronic + + + align:start position:0% +important thing about the electronic +structure that you're going to need to + + align:start position:0% +structure that you're going to need to + + + align:start position:0% +structure that you're going to need to +know and as a graduate student I was + + align:start position:0% +know and as a graduate student I was + + + align:start position:0% +know and as a graduate student I was +collecting numbers I was collecting + + align:start position:0% +collecting numbers I was collecting + + + align:start position:0% +collecting numbers I was collecting +numbers about spectroscopic + + align:start position:0% +numbers about spectroscopic + + + align:start position:0% +numbers about spectroscopic +perturbations where non-degenerate + + align:start position:0% +perturbations where non-degenerate + + + align:start position:0% +perturbations where non-degenerate +perturbation theory breaks down and + + align:start position:0% +perturbation theory breaks down and + + + align:start position:0% +perturbation theory breaks down and +interesting things happened but this was + + align:start position:0% +interesting things happened but this was + + + align:start position:0% +interesting things happened but this was +something that nobody in the world was + + align:start position:0% +something that nobody in the world was + + + align:start position:0% +something that nobody in the world was +interested in because it was the + + align:start position:0% +interested in because it was the + + + align:start position:0% +interested in because it was the +breaking of the usual patterns and I was + + align:start position:0% +breaking of the usual patterns and I was + + + align:start position:0% +breaking of the usual patterns and I was +convinced that I had collected some + + align:start position:0% +convinced that I had collected some + + + align:start position:0% +convinced that I had collected some +stuff that told an interesting story and + + align:start position:0% +stuff that told an interesting story and + + + align:start position:0% +stuff that told an interesting story and +I told Klemperer about this and he said + + align:start position:0% +I told Klemperer about this and he said + + + align:start position:0% +I told Klemperer about this and he said +well have you thought about how to + + align:start position:0% +well have you thought about how to + + + align:start position:0% +well have you thought about how to +evaluate the these integrals that you're + + align:start position:0% +evaluate the these integrals that you're + + + align:start position:0% +evaluate the these integrals that you're +these numbers that you are extracting + + align:start position:0% +these numbers that you are extracting + + + align:start position:0% +these numbers that you are extracting +from the spectrum by doing some tricks + + align:start position:0% +from the spectrum by doing some tricks + + + align:start position:0% +from the spectrum by doing some tricks +with the many electron wave functions + + align:start position:0% +with the many electron wave functions + + + align:start position:0% +with the many electron wave functions +and then he showed me and a scrap of + + align:start position:0% +and then he showed me and a scrap of + + + align:start position:0% +and then he showed me and a scrap of +paper how to do it and I was launched + + align:start position:0% +paper how to do it and I was launched + + + align:start position:0% +paper how to do it and I was launched +that was it that has been the foundation + + align:start position:0% +that was it that has been the foundation + + + align:start position:0% +that was it that has been the foundation +of my career for the last 50 years and I + + align:start position:0% +of my career for the last 50 years and I + + + align:start position:0% +of my career for the last 50 years and I +didn't think that klemper knew that I + + align:start position:0% +didn't think that klemper knew that I + + + align:start position:0% +didn't think that klemper knew that I +didn't think anybody do it because I + + align:start position:0% +didn't think anybody do it because I + + + align:start position:0% +didn't think anybody do it because I +didn't think it was to be knowable but + + align:start position:0% +didn't think it was to be knowable but + + + align:start position:0% +didn't think it was to be knowable but +he just gave it to me in a silver + + align:start position:0% +he just gave it to me in a silver + + + align:start position:0% +he just gave it to me in a silver +platter and so I'm going to try to give + + align:start position:0% +platter and so I'm going to try to give + + + align:start position:0% +platter and so I'm going to try to give +you at least the rudiments of what it is + + align:start position:0% +you at least the rudiments of what it is + + + align:start position:0% +you at least the rudiments of what it is +you're up against and how you reduce + + align:start position:0% +you're up against and how you reduce + + + align:start position:0% +you're up against and how you reduce +them to things that you care about that + + align:start position:0% +them to things that you care about that + + + align:start position:0% +them to things that you care about that +you can think about and you can + + align:start position:0% +you can think about and you can + + + align:start position:0% +you can think about and you can +understand the hydrogen atom in rather + + align:start position:0% +understand the hydrogen atom in rather + + + align:start position:0% +understand the hydrogen atom in rather +complete detail or at least you can + + align:start position:0% +complete detail or at least you can + + + align:start position:0% +complete detail or at least you can +understand how one observable relates to + + align:start position:0% +understand how one observable relates to + + + align:start position:0% +understand how one observable relates to +another and so the relationship between + + align:start position:0% +another and so the relationship between + + + align:start position:0% +another and so the relationship between +the effective quantum number and the + + align:start position:0% +the effective quantum number and the + + + align:start position:0% +the effective quantum number and the +ionization energy of a state then + + align:start position:0% +ionization energy of a state then + + + align:start position:0% +ionization energy of a state then +provides a hydrogen atom based + + align:start position:0% +provides a hydrogen atom based + + + align:start position:0% +provides a hydrogen atom based +structural model for everything you can + + align:start position:0% +structural model for everything you can + + + align:start position:0% +structural model for everything you can +observe now spectroscopy have the + + align:start position:0% +observe now spectroscopy have the + + + align:start position:0% +observe now spectroscopy have the +unfortunate habit of saying we're + + align:start position:0% +unfortunate habit of saying we're + + + align:start position:0% +unfortunate habit of saying we're +interested in is structure structure is + + align:start position:0% +interested in is structure structure is + + + align:start position:0% +interested in is structure structure is +static dynamics is magical and special + + align:start position:0% +static dynamics is magical and special + + + align:start position:0% +static dynamics is magical and special +and hard but if you understand structure + + align:start position:0% +and hard but if you understand structure + + + align:start position:0% +and hard but if you understand structure +in a way which is not the exact eigen + + align:start position:0% +in a way which is not the exact eigen + + + align:start position:0% +in a way which is not the exact eigen +States not the exact wave functions but + + align:start position:0% +States not the exact wave functions but + + + align:start position:0% +States not the exact wave functions but +something that the molecule was trying + + align:start position:0% +something that the molecule was trying + + + align:start position:0% +something that the molecule was trying +to do and sort of missed and the the + + align:start position:0% +to do and sort of missed and the the + + + align:start position:0% +to do and sort of missed and the the +dynamics is just what happens when this + + align:start position:0% +dynamics is just what happens when this + + + align:start position:0% +dynamics is just what happens when this +preparation isn't an eigenstate which + + align:start position:0% +preparation isn't an eigenstate which + + + align:start position:0% +preparation isn't an eigenstate which +would be boring and you get dynamics + + align:start position:0% +would be boring and you get dynamics + + + align:start position:0% +would be boring and you get dynamics +which you can understand as opposed to + + align:start position:0% +which you can understand as opposed to + + + align:start position:0% +which you can understand as opposed to +just say I'm going to I'm going to + + align:start position:0% +just say I'm going to I'm going to + + + align:start position:0% +just say I'm going to I'm going to +tabulate the dynamics to still do you + + align:start position:0% +tabulate the dynamics to still do you + + + align:start position:0% +tabulate the dynamics to still do you +don't know anything unless you have a + + align:start position:0% +don't know anything unless you have a + + + align:start position:0% +don't know anything unless you have a +reductionist picture of what's going on + + align:start position:0% +reductionist picture of what's going on + + + align:start position:0% +reductionist picture of what's going on +and since the hardest part of dealing + + align:start position:0% +and since the hardest part of dealing + + + align:start position:0% +and since the hardest part of dealing +with molecules is the fact that they + + align:start position:0% +with molecules is the fact that they + + + align:start position:0% +with molecules is the fact that they +have a lot of electrons this is really + + align:start position:0% +have a lot of electrons this is really + + + align:start position:0% +have a lot of electrons this is really +the core of being able to do important + + align:start position:0% +the core of being able to do important + + + align:start position:0% +the core of being able to do important +stuff now + + align:start position:0% +stuff now + + + align:start position:0% +stuff now +it's it's a horrendously complicated + + align:start position:0% +it's it's a horrendously complicated + + + align:start position:0% +it's it's a horrendously complicated +problem and notationally awkward too and + + align:start position:0% +problem and notationally awkward too and + + + align:start position:0% +problem and notationally awkward too and +let me just try to let me try to explain + + align:start position:0% +let me just try to let me try to explain + + + align:start position:0% +let me just try to let me try to explain +it and I'm going to try to do this + + align:start position:0% +it and I'm going to try to do this + + + align:start position:0% +it and I'm going to try to do this +without too much reliance on my notes + + align:start position:0% +without too much reliance on my notes + + + align:start position:0% +without too much reliance on my notes +because they're terrible okay but we + + align:start position:0% +because they're terrible okay but we + + + align:start position:0% +because they're terrible okay but we +have we talked about helium and helium + + align:start position:0% +have we talked about helium and helium + + + align:start position:0% +have we talked about helium and helium +has two electrons and there is this 1 + + align:start position:0% +has two electrons and there is this 1 + + + align:start position:0% +has two electrons and there is this 1 +over r12 interaction between electrons + + align:start position:0% +over r12 interaction between electrons + + + align:start position:0% +over r12 interaction between electrons +which looks innocent enough you can + + align:start position:0% +which looks innocent enough you can + + + align:start position:0% +which looks innocent enough you can +write it down and you know just a few + + align:start position:0% +write it down and you know just a few + + + align:start position:0% +write it down and you know just a few +symbols but and we can call it the first + + align:start position:0% +symbols but and we can call it the first + + + align:start position:0% +symbols but and we can call it the first +order perturbation but that's really a + + align:start position:0% +order perturbation but that's really a + + + align:start position:0% +order perturbation but that's really a +lie because it's as big as almost + + align:start position:0% +lie because it's as big as almost + + + align:start position:0% +lie because it's as big as almost +everything else and so yeah we can in + + align:start position:0% +everything else and so yeah we can in + + + align:start position:0% +everything else and so yeah we can in +fact do a series of approximations one + + align:start position:0% +fact do a series of approximations one + + + align:start position:0% +fact do a series of approximations one +is ignore it they're not interacting + + align:start position:0% +is ignore it they're not interacting + + + align:start position:0% +is ignore it they're not interacting +electron approximation and that's + + align:start position:0% +electron approximation and that's + + + align:start position:0% +electron approximation and that's +basically repackaging hydrogen and it's + + align:start position:0% +basically repackaging hydrogen and it's + + + align:start position:0% +basically repackaging hydrogen and it's +not quite enough and then we can say ok + + align:start position:0% +not quite enough and then we can say ok + + + align:start position:0% +not quite enough and then we can say ok +let's let's calculate the first order + + align:start position:0% +let's let's calculate the first order + + + align:start position:0% +let's let's calculate the first order +energy by calculating expectation values + + align:start position:0% +energy by calculating expectation values + + + align:start position:0% +energy by calculating expectation values +of H 1 2 so that's a 1 that's and that's + + align:start position:0% +of H 1 2 so that's a 1 that's and that's + + + align:start position:0% +of H 1 2 so that's a 1 that's and that's +almost enough to give us a sense of what + + align:start position:0% +almost enough to give us a sense of what + + + align:start position:0% +almost enough to give us a sense of what +is going on + + align:start position:0% + + + + align:start position:0% + +ok 1 over r12 commutator with with any + + align:start position:0% +ok 1 over r12 commutator with with any + + + align:start position:0% +ok 1 over r12 commutator with with any +electron that's not 0 1 over r12 + + align:start position:0% +electron that's not 0 1 over r12 + + + align:start position:0% +electron that's not 0 1 over r12 +commutator with any any orbital angular + + align:start position:0% +commutator with any any orbital angular + + + align:start position:0% +commutator with any any orbital angular +momentum any momentum not 0 so that + + align:start position:0% +momentum any momentum not 0 so that + + + align:start position:0% +momentum any momentum not 0 so that +means that L and n are not + + align:start position:0% + + + + align:start position:0% + +good a lot of members let's have good + + align:start position:0% +good a lot of members let's have good + + + align:start position:0% +good a lot of members let's have good +quantum number what's the definition of + + align:start position:0% +quantum number what's the definition of + + + align:start position:0% +quantum number what's the definition of +a good quantum number come on this is an + + align:start position:0% +a good quantum number come on this is an + + + align:start position:0% +a good quantum number come on this is an +important question yes that's that's + + align:start position:0% +important question yes that's that's + + + align:start position:0% +important question yes that's that's +maybe 70% of what I want you can put + + align:start position:0% +maybe 70% of what I want you can put + + + align:start position:0% +maybe 70% of what I want you can put +into a formula that means it's a + + align:start position:0% +into a formula that means it's a + + + align:start position:0% +into a formula that means it's a +rigorously good thing it means it + + align:start position:0% +rigorously good thing it means it + + + align:start position:0% +rigorously good thing it means it +commutes with the Hamiltonian a + + align:start position:0% +commutes with the Hamiltonian a + + + align:start position:0% +commutes with the Hamiltonian a +rigorously good quantum number is an + + align:start position:0% +rigorously good quantum number is an + + + align:start position:0% +rigorously good quantum number is an +corresponds to an eigenvalue of an + + align:start position:0% +corresponds to an eigenvalue of an + + + align:start position:0% +corresponds to an eigenvalue of an +operator that commutes with the + + align:start position:0% +operator that commutes with the + + + align:start position:0% +operator that commutes with the +Hamiltonian so hydrogen we rely on NL to + + align:start position:0% +Hamiltonian so hydrogen we rely on NL to + + + align:start position:0% +Hamiltonian so hydrogen we rely on NL to +get almost everything but here we find + + align:start position:0% +get almost everything but here we find + + + align:start position:0% +get almost everything but here we find +that in addition to this being not small + + align:start position:0% +that in addition to this being not small + + + align:start position:0% +that in addition to this being not small +it destroys the foundation of our + + align:start position:0% +it destroys the foundation of our + + + align:start position:0% +it destroys the foundation of our +picture and so how do we how do we think + + align:start position:0% +picture and so how do we how do we think + + + align:start position:0% +picture and so how do we how do we think +that we can make any sense of many + + align:start position:0% +that we can make any sense of many + + + align:start position:0% +that we can make any sense of many +electron atoms and molecules well it + + align:start position:0% +electron atoms and molecules well it + + + align:start position:0% +electron atoms and molecules well it +turns out we can hide most of the + + align:start position:0% +turns out we can hide most of the + + + align:start position:0% +turns out we can hide most of the +complexity and most of the complexity is + + align:start position:0% +complexity and most of the complexity is + + + align:start position:0% +complexity and most of the complexity is +just working out the rules for + + align:start position:0% +just working out the rules for + + + align:start position:0% +just working out the rules for +calculating these matrix elements the + + align:start position:0% +calculating these matrix elements the + + + align:start position:0% +calculating these matrix elements the +matrix elements of operators that we + + align:start position:0% +matrix elements of operators that we + + + align:start position:0% +matrix elements of operators that we +care about like transition moments + + align:start position:0% +care about like transition moments + + + align:start position:0% +care about like transition moments +spin-orbit same and effect things that + + align:start position:0% +spin-orbit same and effect things that + + + align:start position:0% +spin-orbit same and effect things that +that they correspond to how we observe + + align:start position:0% +that they correspond to how we observe + + + align:start position:0% +that they correspond to how we observe +atomic and molecular structure and and + + align:start position:0% +atomic and molecular structure and and + + + align:start position:0% +atomic and molecular structure and and +so the main obstacle to being able to + + align:start position:0% +so the main obstacle to being able to + + + align:start position:0% +so the main obstacle to being able to +evaluate these matrix elements is the + + align:start position:0% +evaluate these matrix elements is the + + + align:start position:0% +evaluate these matrix elements is the +permutation requirement + + align:start position:0% + + + + align:start position:0% + +and it turns out that there is a really + + align:start position:0% +and it turns out that there is a really + + + align:start position:0% +and it turns out that there is a really +simple way of dealing with the + + align:start position:0% +simple way of dealing with the + + + align:start position:0% +simple way of dealing with the +requirements for electron permutation + + align:start position:0% +requirements for electron permutation + + + align:start position:0% +requirements for electron permutation +and that that is to write the wave + + align:start position:0% +and that that is to write the wave + + + align:start position:0% +and that that is to write the wave +function as a determinant of one + + align:start position:0% +function as a determinant of one + + + align:start position:0% +function as a determinant of one +electron orbitals because a determinant + + align:start position:0% +electron orbitals because a determinant + + + align:start position:0% +electron orbitals because a determinant +has to three really important problems + + align:start position:0% +has to three really important problems + + + align:start position:0% +has to three really important problems +with properties one it changes its sign + + align:start position:0% +with properties one it changes its sign + + + align:start position:0% +with properties one it changes its sign +when you permute any two columns - it + + align:start position:0% +when you permute any two columns - it + + + align:start position:0% +when you permute any two columns - it +changes its sign when you permute any + + align:start position:0% +changes its sign when you permute any + + + align:start position:0% +changes its sign when you permute any +two rows and three if you have two + + align:start position:0% +two rows and three if you have two + + + align:start position:0% +two rows and three if you have two +identical columns or rows at 0 that's + + align:start position:0% +identical columns or rows at 0 that's + + + align:start position:0% +identical columns or rows at 0 that's +that's really fantastic and that is the + + align:start position:0% +that's really fantastic and that is the + + + align:start position:0% +that's really fantastic and that is the +Pauli exclusion principle not what you + + align:start position:0% +Pauli exclusion principle not what you + + + align:start position:0% +Pauli exclusion principle not what you +learned in high school what you learned + + align:start position:0% +learned in high school what you learned + + + align:start position:0% +learned in high school what you learned +is a small consequence of that so if we + + align:start position:0% +is a small consequence of that so if we + + + align:start position:0% +is a small consequence of that so if we +can build at a symmetric wave functions + + align:start position:0% +can build at a symmetric wave functions + + + align:start position:0% +can build at a symmetric wave functions +we have alpha we have we can only put + + align:start position:0% +we have alpha we have we can only put + + + align:start position:0% +we have alpha we have we can only put +one electron in an orbital we have all + + align:start position:0% +one electron in an orbital we have all + + + align:start position:0% +one electron in an orbital we have all +sorts of stuff but it's too complicated + + align:start position:0% +sorts of stuff but it's too complicated + + + align:start position:0% +sorts of stuff but it's too complicated +to tell a student in high school that + + align:start position:0% +to tell a student in high school that + + + align:start position:0% +to tell a student in high school that +you can't just the question of + + align:start position:0% +you can't just the question of + + + align:start position:0% +you can't just the question of +indistinguishable electrons is such a + + align:start position:0% +indistinguishable electrons is such a + + + align:start position:0% +indistinguishable electrons is such a +subtle thing that you can't say well + + align:start position:0% +subtle thing that you can't say well + + + align:start position:0% +subtle thing that you can't say well +they have to be anti symmetric that but + + align:start position:0% +they have to be anti symmetric that but + + + align:start position:0% +they have to be anti symmetric that but +it's easy to say you can't put more than + + align:start position:0% +it's easy to say you can't put more than + + + align:start position:0% +it's easy to say you can't put more than +one electron in a in a spin orbital but + + align:start position:0% +one electron in a in a spin orbital but + + + align:start position:0% +one electron in a in a spin orbital but +we don't talk about spin orbitals we say + + align:start position:0% +we don't talk about spin orbitals we say + + + align:start position:0% +we don't talk about spin orbitals we say +we can't put more than two electrons in + + align:start position:0% +we can't put more than two electrons in + + + align:start position:0% +we can't put more than two electrons in +an orbital because we're protecting you + + align:start position:0% +an orbital because we're protecting you + + + align:start position:0% +an orbital because we're protecting you +from from unnecessary knowledge ok well + + align:start position:0% +from from unnecessary knowledge ok well + + + align:start position:0% +from from unnecessary knowledge ok well +I'm not gonna protect you ok so we know + + align:start position:0% +I'm not gonna protect you ok so we know + + + align:start position:0% +I'm not gonna protect you ok so we know +that the Hamiltonian passed it + + align:start position:0% +that the Hamiltonian passed it + + + align:start position:0% +that the Hamiltonian passed it +commute with these capital letters mean + + align:start position:0% +commute with these capital letters mean + + + align:start position:0% +commute with these capital letters mean +many electron angular momenta and this + + align:start position:0% +many electron angular momenta and this + + + align:start position:0% +many electron angular momenta and this +is the spin this is the projection of + + align:start position:0% +is the spin this is the projection of + + + align:start position:0% +is the spin this is the projection of +the spin we know this is true because + + align:start position:0% +the spin we know this is true because + + + align:start position:0% +the spin we know this is true because +the Hamiltonian doesn't operate on spin + + align:start position:0% +the Hamiltonian doesn't operate on spin + + + align:start position:0% +the Hamiltonian doesn't operate on spin +it's a trivial result but it's a very + + align:start position:0% +it's a trivial result but it's a very + + + align:start position:0% +it's a trivial result but it's a very +important result ok so we have to worry + + align:start position:0% +important result ok so we have to worry + + + align:start position:0% +important result ok so we have to worry +about spin and spin eigenstates and + + align:start position:0% +about spin and spin eigenstates and + + + align:start position:0% +about spin and spin eigenstates and +other things like that + + align:start position:0% +other things like that + + + align:start position:0% +other things like that +okay so Slater determines Jacey Slater + + align:start position:0% +okay so Slater determines Jacey Slater + + + align:start position:0% +okay so Slater determines Jacey Slater +was an MIT professor in physics he + + align:start position:0% +was an MIT professor in physics he + + + align:start position:0% +was an MIT professor in physics he +invented these things in 1929 I have a + + align:start position:0% +invented these things in 1929 I have a + + + align:start position:0% +invented these things in 1929 I have a +reference I I don't know if I've ever + + align:start position:0% +reference I I don't know if I've ever + + + align:start position:0% +reference I I don't know if I've ever +read this paper but it it's probably + + align:start position:0% +read this paper but it it's probably + + + align:start position:0% +read this paper but it it's probably +beautiful so basically what Slater did + + align:start position:0% +beautiful so basically what Slater did + + + align:start position:0% +beautiful so basically what Slater did +is showed yeah you can you can do the + + align:start position:0% +is showed yeah you can you can do the + + + align:start position:0% +is showed yeah you can you can do the +necessary algebra to deal with any atom + + align:start position:0% +necessary algebra to deal with any atom + + + align:start position:0% +necessary algebra to deal with any atom +and to be able to reduce an atom to a + + align:start position:0% +and to be able to reduce an atom to a + + + align:start position:0% +and to be able to reduce an atom to a +small number of integrals do you really + + align:start position:0% +small number of integrals do you really + + + align:start position:0% +small number of integrals do you really +care about and there are two ways of + + align:start position:0% +care about and there are two ways of + + + align:start position:0% +care about and there are two ways of +doing this one is the truth and when + + align:start position:0% +doing this one is the truth and when + + + align:start position:0% +doing this one is the truth and when +it's a fit model now the truth + + align:start position:0% +it's a fit model now the truth + + + align:start position:0% +it's a fit model now the truth +is really boring because you lose all + + align:start position:0% +is really boring because you lose all + + + align:start position:0% +is really boring because you lose all +the insights and the fit model this + + align:start position:0% +the insights and the fit model this + + + align:start position:0% +the insights and the fit model this +gives you the things you have to think + + align:start position:0% +gives you the things you have to think + + + align:start position:0% +gives you the things you have to think +about and understand and a fit model + + align:start position:0% +about and understand and a fit model + + + align:start position:0% +about and understand and a fit model +also tells you what are the important + + align:start position:0% +also tells you what are the important + + + align:start position:0% +also tells you what are the important +actors and maybe they're in costume + + align:start position:0% +actors and maybe they're in costume + + + align:start position:0% +actors and maybe they're in costume +maybe they're not but you know we can we + + align:start position:0% +maybe they're not but you know we can we + + + align:start position:0% +maybe they're not but you know we can we +can deal with them but the truth is + + align:start position:0% +can deal with them but the truth is + + + align:start position:0% +can deal with them but the truth is +really very complicated and as I said + + align:start position:0% +really very complicated and as I said + + + align:start position:0% +really very complicated and as I said +many times when you go from hydrogen to + + align:start position:0% +many times when you go from hydrogen to + + + align:start position:0% +many times when you go from hydrogen to +helium you can't solve the shorter + + align:start position:0% +helium you can't solve the shorter + + + align:start position:0% +helium you can't solve the shorter +equation exactly this was a this was + + align:start position:0% +equation exactly this was a this was + + + align:start position:0% +equation exactly this was a this was +perhaps a little bit of a surprise but I + + align:start position:0% +perhaps a little bit of a surprise but I + + + align:start position:0% +perhaps a little bit of a surprise but I +think it was only surprising newspapers + + align:start position:0% +think it was only surprising newspapers + + + align:start position:0% +think it was only surprising newspapers +I think physicists knew immediately when + + align:start position:0% +I think physicists knew immediately when + + + align:start position:0% +I think physicists knew immediately when +you go from a two-body problem to a + + align:start position:0% +you go from a two-body problem to a + + + align:start position:0% +you go from a two-body problem to a +three-body problem there is no way you + + align:start position:0% +three-body problem there is no way you + + + align:start position:0% +three-body problem there is no way you +can have an exact solution and that's + + align:start position:0% +can have an exact solution and that's + + + align:start position:0% +can have an exact solution and that's +the truth you can't solve helium or any + + align:start position:0% +the truth you can't solve helium or any + + + align:start position:0% +the truth you can't solve helium or any +more than one electron problem exactly + + align:start position:0% +more than one electron problem exactly + + + align:start position:0% +more than one electron problem exactly +but you can do really well and it just + + align:start position:0% +but you can do really well and it just + + + align:start position:0% +but you can do really well and it just +cost computer time and if the computer + + align:start position:0% +cost computer time and if the computer + + + align:start position:0% +cost computer time and if the computer +is doing the work you don't really care + + align:start position:0% +is doing the work you don't really care + + + align:start position:0% +is doing the work you don't really care +because once you've told the computer + + align:start position:0% +because once you've told the computer + + + align:start position:0% +because once you've told the computer +the rules then it's off to the races you + + align:start position:0% +the rules then it's off to the races you + + + align:start position:0% +the rules then it's off to the races you +can go have lunch or you can go have a + + align:start position:0% +can go have lunch or you can go have a + + + align:start position:0% +can go have lunch or you can go have a +life and come back and and the computer + + align:start position:0% +life and come back and and the computer + + + align:start position:0% +life and come back and and the computer +will tell you whether you made a mistake + + align:start position:0% +will tell you whether you made a mistake + + + align:start position:0% +will tell you whether you made a mistake +and you're getting a nonsense result or + + align:start position:0% +and you're getting a nonsense result or + + + align:start position:0% +and you're getting a nonsense result or +that you have the correct result okay so + + align:start position:0% +that you have the correct result okay so + + + align:start position:0% +that you have the correct result okay so +what we know is this permutation + + align:start position:0% +what we know is this permutation + + + align:start position:0% +what we know is this permutation +operator operating on any two electron + + align:start position:0% +operator operating on any two electron + + + align:start position:0% +operator operating on any two electron +function has to make + + align:start position:0% + + + + align:start position:0% + +okay I'm skipping steps and I've I I + + align:start position:0% +okay I'm skipping steps and I've I I + + + align:start position:0% +okay I'm skipping steps and I've I I +know it's a really kind of stupid + + align:start position:0% +know it's a really kind of stupid + + + align:start position:0% +know it's a really kind of stupid +sometimes + + align:start position:0% +sometimes + + + align:start position:0% +sometimes +p21 which has to be equal to - okay + + align:start position:0% +p21 which has to be equal to - okay + + + align:start position:0% +p21 which has to be equal to - okay +that's that's and now if you fly the + + align:start position:0% +that's that's and now if you fly the + + + align:start position:0% +that's that's and now if you fly the +permutation operator twice you get back + + align:start position:0% +permutation operator twice you get back + + + align:start position:0% +permutation operator twice you get back +to the same thing so there's only two + + align:start position:0% +to the same thing so there's only two + + + align:start position:0% +to the same thing so there's only two +possible eigenvalues you can have minus + + align:start position:0% +possible eigenvalues you can have minus + + + align:start position:0% +possible eigenvalues you can have minus +1 or plus 1 and the minus 1 corresponds + + align:start position:0% +1 or plus 1 and the minus 1 corresponds + + + align:start position:0% +1 or plus 1 and the minus 1 corresponds +to fermions things that have + + align:start position:0% +to fermions things that have + + + align:start position:0% +to fermions things that have +half-integer spin like electrons and the + + align:start position:0% +half-integer spin like electrons and the + + + align:start position:0% +half-integer spin like electrons and the +plus 1 head of course - such things that + + align:start position:0% +plus 1 head of course - such things that + + + align:start position:0% +plus 1 head of course - such things that +have integer spin like photons and + + align:start position:0% +have integer spin like photons and + + + align:start position:0% +have integer spin like photons and +vibrance and other things and actually + + align:start position:0% +vibrance and other things and actually + + + align:start position:0% +vibrance and other things and actually +it's harder to construct a symmetric + + align:start position:0% +it's harder to construct a symmetric + + + align:start position:0% +it's harder to construct a symmetric +function than an anti-symmetric function + + align:start position:0% +function than an anti-symmetric function + + + align:start position:0% +function than an anti-symmetric function +but the thing is you've got lots of + + align:start position:0% +but the thing is you've got lots of + + + align:start position:0% +but the thing is you've got lots of +electrons and you have very few quanta + + align:start position:0% +electrons and you have very few quanta + + + align:start position:0% +electrons and you have very few quanta +of vibrations in a single mode and you + + align:start position:0% +of vibrations in a single mode and you + + + align:start position:0% +of vibrations in a single mode and you +have very few photons interacting with a + + align:start position:0% +have very few photons interacting with a + + + align:start position:0% +have very few photons interacting with a +molecule at once and so the symmetry of + + align:start position:0% +molecule at once and so the symmetry of + + + align:start position:0% +molecule at once and so the symmetry of +the cement of the the boson symmetry is + + align:start position:0% +the cement of the the boson symmetry is + + + align:start position:0% +the cement of the the boson symmetry is +less important in most applications and + + align:start position:0% +less important in most applications and + + + align:start position:0% +less important in most applications and +so we just have to kill this one ok + + align:start position:0% + + + + align:start position:0% + +so suppose we want to talk about + + align:start position:0% +so suppose we want to talk about + + + align:start position:0% +so suppose we want to talk about +something like this the 1 s 2 s + + align:start position:0% +something like this the 1 s 2 s + + + align:start position:0% +something like this the 1 s 2 s +configuration a configuration is the + + align:start position:0% +configuration a configuration is the + + + align:start position:0% +configuration a configuration is the +list of the occupied orbitals not the + + align:start position:0% +list of the occupied orbitals not the + + + align:start position:0% +list of the occupied orbitals not the +occupied spin orbitals which is a spin + + align:start position:0% +occupied spin orbitals which is a spin + + + align:start position:0% +occupied spin orbitals which is a spin +associated with an orbital which is what + + align:start position:0% +associated with an orbital which is what + + + align:start position:0% +associated with an orbital which is what +I the world of spin orbitals is where I + + align:start position:0% +I the world of spin orbitals is where I + + + align:start position:0% +I the world of spin orbitals is where I +live + + align:start position:0% +live + + + align:start position:0% +live +but we we do that for a reason okay and + + align:start position:0% +but we we do that for a reason okay and + + + align:start position:0% +but we we do that for a reason okay and +so this 2 electron thing can be + + align:start position:0% +so this 2 electron thing can be + + + align:start position:0% +so this 2 electron thing can be +expressed as a space part + + align:start position:0% + + + + align:start position:0% + +there are various conventions that I'm + + align:start position:0% +there are various conventions that I'm + + + align:start position:0% +there are various conventions that I'm +just been part and alpha 1 beta 2 and + + align:start position:0% +just been part and alpha 1 beta 2 and + + + align:start position:0% +just been part and alpha 1 beta 2 and +then we have minus or plus there you + + align:start position:0% +then we have minus or plus there you + + + align:start position:0% +then we have minus or plus there you +know 1 alpha 2 I'm looking at my notes + + align:start position:0% +know 1 alpha 2 I'm looking at my notes + + + align:start position:0% +know 1 alpha 2 I'm looking at my notes +because some people always can keep the + + align:start position:0% +because some people always can keep the + + + align:start position:0% +because some people always can keep the +electron in the first position and some + + align:start position:0% +electron in the first position and some + + + align:start position:0% +electron in the first position and some +people keep always this the the orbital + + align:start position:0% +people keep always this the the orbital + + + align:start position:0% +people keep always this the the orbital +in the first position and it doesn't + + align:start position:0% +in the first position and it doesn't + + + align:start position:0% +in the first position and it doesn't +matter because you can you can permute + + align:start position:0% +matter because you can you can permute + + + align:start position:0% +matter because you can you can permute +REOs or columns but i just want to write + + align:start position:0% +REOs or columns but i just want to write + + + align:start position:0% +REOs or columns but i just want to write +what is in my notes okay so this thing + + align:start position:0% +what is in my notes okay so this thing + + + align:start position:0% +what is in my notes okay so this thing +this two electron function has two has + + align:start position:0% +this two electron function has two has + + + align:start position:0% +this two electron function has two has +two anti symmetrized possibilities and + + align:start position:0% +two anti symmetrized possibilities and + + + align:start position:0% +two anti symmetrized possibilities and +one is a singlet and one is a triplet so + + align:start position:0% +one is a singlet and one is a triplet so + + + align:start position:0% +one is a singlet and one is a triplet so +s equals 0 s equals 1 we recognize this + + align:start position:0% +s equals 0 s equals 1 we recognize this + + + align:start position:0% +s equals 0 s equals 1 we recognize this +alpha beta minus beta alpha as the + + align:start position:0% +alpha beta minus beta alpha as the + + + align:start position:0% +alpha beta minus beta alpha as the +singlet spin state and alpha beta plus + + align:start position:0% +singlet spin state and alpha beta plus + + + align:start position:0% +singlet spin state and alpha beta plus +beta alpha as the triplets in state so + + align:start position:0% +beta alpha as the triplets in state so + + + align:start position:0% +beta alpha as the triplets in state so +we have alpha beta plus beta alpha and + + align:start position:0% +we have alpha beta plus beta alpha and + + + align:start position:0% +we have alpha beta plus beta alpha and +alpha alpha and beta beta and we have + + align:start position:0% +alpha alpha and beta beta and we have + + + align:start position:0% +alpha alpha and beta beta and we have +alpha beta minus beta alpha so we call s + + align:start position:0% +alpha beta minus beta alpha so we call s + + + align:start position:0% +alpha beta minus beta alpha so we call s +equals 0 a singlet and this a triplet + + align:start position:0% +equals 0 a singlet and this a triplet + + + align:start position:0% +equals 0 a singlet and this a triplet +because of the number of states and this + + align:start position:0% +because of the number of states and this + + + align:start position:0% +because of the number of states and this +wave function has as the necessary spin + + align:start position:0% +wave function has as the necessary spin + + + align:start position:0% +wave function has as the necessary spin +symmetry and the necessary permutation + + align:start position:0% +symmetry and the necessary permutation + + + align:start position:0% +symmetry and the necessary permutation +symmetry ok + + align:start position:0% + + + + align:start position:0% + +so if instead of two electrons we have + + align:start position:0% +so if instead of two electrons we have + + + align:start position:0% +so if instead of two electrons we have +1/2 n then mr. Slater says so that's a + + align:start position:0% +1/2 n then mr. Slater says so that's a + + + align:start position:0% +1/2 n then mr. Slater says so that's a +determinant and then by n determinant + + align:start position:0% +determinant and then by n determinant + + + align:start position:0% +determinant and then by n determinant +and the rows correspond to the electrons + + align:start position:0% +and the rows correspond to the electrons + + + align:start position:0% +and the rows correspond to the electrons +and the columns correspond to the + + align:start position:0% +and the columns correspond to the + + + align:start position:0% +and the columns correspond to the +orbitals now this because of the + + align:start position:0% +orbitals now this because of the + + + align:start position:0% +orbitals now this because of the +properties of a determinant at a is anti + + align:start position:0% +properties of a determinant at a is anti + + + align:start position:0% +properties of a determinant at a is anti +symmetric with respect to permutation of + + align:start position:0% +symmetric with respect to permutation of + + + align:start position:0% +symmetric with respect to permutation of +any two electrons or any two orbitals + + align:start position:0% +any two electrons or any two orbitals + + + align:start position:0% +any two electrons or any two orbitals +but we don't really care about the + + align:start position:0% +but we don't really care about the + + + align:start position:0% +but we don't really care about the +permutation of the orbitals because + + align:start position:0% +permutation of the orbitals because + + + align:start position:0% +permutation of the orbitals because +really the same thing as permutation and + + align:start position:0% +really the same thing as permutation and + + + align:start position:0% +really the same thing as permutation and +so this n factorial is a consequence of + + align:start position:0% +so this n factorial is a consequence of + + + align:start position:0% +so this n factorial is a consequence of +normalization because when you expand an + + align:start position:0% +normalization because when you expand an + + + align:start position:0% +normalization because when you expand an +N by n determinant you get n factorial + + align:start position:0% +N by n determinant you get n factorial + + + align:start position:0% +N by n determinant you get n factorial +additive products of n functions looks + + align:start position:0% +additive products of n functions looks + + + align:start position:0% +additive products of n functions looks +horrible and because we're normalizing + + align:start position:0% +horrible and because we're normalizing + + + align:start position:0% +horrible and because we're normalizing +we need this 1 over the square root of n + + align:start position:0% +we need this 1 over the square root of n + + + align:start position:0% +we need this 1 over the square root of n +factorial in order to have this thing + + align:start position:0% +factorial in order to have this thing + + + align:start position:0% +factorial in order to have this thing +come out to be 1 when you calculating + + align:start position:0% +come out to be 1 when you calculating + + + align:start position:0% +come out to be 1 when you calculating +the normalization integral okay now this + + align:start position:0% +the normalization integral okay now this + + + align:start position:0% +the normalization integral okay now this +notation is horrible because you've got + + align:start position:0% +notation is horrible because you've got + + + align:start position:0% +notation is horrible because you've got +too many symbols and so depending on + + align:start position:0% +too many symbols and so depending on + + + align:start position:0% +too many symbols and so depending on +what you're trying to convey you reduce + + align:start position:0% +what you're trying to convey you reduce + + + align:start position:0% +what you're trying to convey you reduce +the symbols and you can reduce it simply + + align:start position:0% +the symbols and you can reduce it simply + + + align:start position:0% +the symbols and you can reduce it simply +by instead of writing sy every time just + + align:start position:0% +by instead of writing sy every time just + + + align:start position:0% +by instead of writing sy every time just +writing the state or you can it since + + align:start position:0% +writing the state or you can it since + + + align:start position:0% +writing the state or you can it since +you + + align:start position:0% +you + + + align:start position:0% +you +you don't need to sigh you don't need + + align:start position:0% +you don't need to sigh you don't need + + + align:start position:0% +you don't need to sigh you don't need +the state letter you can just have the + + align:start position:0% +the state letter you can just have the + + + align:start position:0% +the state letter you can just have the +state number and but the best way to do + + align:start position:0% +state number and but the best way to do + + + align:start position:0% +state number and but the best way to do +this is simply to say this is just the + + align:start position:0% +this is simply to say this is just the + + + align:start position:0% +this is simply to say this is just the +main diagonal of the determinant it + + align:start position:0% +main diagonal of the determinant it + + + align:start position:0% +main diagonal of the determinant it +conveys everything you need + + align:start position:0% +conveys everything you need + + + align:start position:0% +conveys everything you need +again if you permute any two of these + + align:start position:0% +again if you permute any two of these + + + align:start position:0% +again if you permute any two of these +guys any adjacent pair the sign changes + + align:start position:0% +guys any adjacent pair the sign changes + + + align:start position:0% +guys any adjacent pair the sign changes +and it contains everything you need and + + align:start position:0% +and it contains everything you need and + + + align:start position:0% +and it contains everything you need and +it's and it doesn't require you to look + + align:start position:0% +it's and it doesn't require you to look + + + align:start position:0% +it's and it doesn't require you to look +at stuff you're not going to use and + + align:start position:0% +at stuff you're not going to use and + + + align:start position:0% +at stuff you're not going to use and +your goal is going to be to take these + + align:start position:0% +your goal is going to be to take these + + + align:start position:0% +your goal is going to be to take these +things and calculate matrix of of them + + align:start position:0% +things and calculate matrix of of them + + + align:start position:0% +things and calculate matrix of of them +and so you'll be dealing with the + + align:start position:0% +and so you'll be dealing with the + + + align:start position:0% +and so you'll be dealing with the +orbitals one or two at a time + + align:start position:0% +orbitals one or two at a time + + + align:start position:0% +orbitals one or two at a time +and this is very convenient and soon you + + align:start position:0% +and this is very convenient and soon you + + + align:start position:0% +and this is very convenient and soon you +start to take this forever granted that + + align:start position:0% +start to take this forever granted that + + + align:start position:0% +start to take this forever granted that +it's a very simple thing but it isn't + + align:start position:0% +it's a very simple thing but it isn't + + + align:start position:0% +it's a very simple thing but it isn't +because you're doing a huge number of + + align:start position:0% +because you're doing a huge number of + + + align:start position:0% +because you're doing a huge number of +tricks okay I'm going to skip over + + align:start position:0% +tricks okay I'm going to skip over + + + align:start position:0% +tricks okay I'm going to skip over +what's in my notes demonstrating that + + align:start position:0% +what's in my notes demonstrating that + + + align:start position:0% +what's in my notes demonstrating that +for a two-by-two that what I asserted is + + align:start position:0% +for a two-by-two that what I asserted is + + + align:start position:0% +for a two-by-two that what I asserted is +correct + + align:start position:0% +correct + + + align:start position:0% +correct +you can do that very easily and so okay + + align:start position:0% +you can do that very easily and so okay + + + align:start position:0% +you can do that very easily and so okay +so we can count and we have an atom and + + align:start position:0% +so we can count and we have an atom and + + + align:start position:0% +so we can count and we have an atom and +we know how many electrons it has and so + + align:start position:0% +we know how many electrons it has and so + + + align:start position:0% +we know how many electrons it has and so +we immediately know what our job is + + align:start position:0% +we immediately know what our job is + + + align:start position:0% +we immediately know what our job is +going to be we're going to be having to + + align:start position:0% +going to be we're going to be having to + + + align:start position:0% +going to be we're going to be having to +write some Slater determinant of those + + align:start position:0% +write some Slater determinant of those + + + align:start position:0% +write some Slater determinant of those +number of electrons and the goal is to + + align:start position:0% +number of electrons and the goal is to + + + align:start position:0% +number of electrons and the goal is to +be able to do the algebra in a way that + + align:start position:0% +be able to do the algebra in a way that + + + align:start position:0% +be able to do the algebra in a way that +maybe you can't describe to your friends + + align:start position:0% +maybe you can't describe to your friends + + + align:start position:0% +maybe you can't describe to your friends +because it's too complicated I'm faced + + align:start position:0% +because it's too complicated I'm faced + + + align:start position:0% +because it's too complicated I'm faced +with the the the problem of trying to + + align:start position:0% +with the the the problem of trying to + + + align:start position:0% +with the the the problem of trying to +explain how to do this algebra but it is + + align:start position:0% +explain how to do this algebra but it is + + + align:start position:0% +explain how to do this algebra but it is +something that you can learn and you + + align:start position:0% +something that you can learn and you + + + align:start position:0% +something that you can learn and you +can't add ask a computer to do it and + + align:start position:0% +can't add ask a computer to do it and + + + align:start position:0% +can't add ask a computer to do it and +there are all sorts of intuitive + + align:start position:0% +there are all sorts of intuitive + + + align:start position:0% +there are all sorts of intuitive +shortcuts + + align:start position:0% +shortcuts + + + align:start position:0% +shortcuts +you can look at a problem and you could + + align:start position:0% +you can look at a problem and you could + + + align:start position:0% +you can look at a problem and you could +say yeah I understand okay so you're + + align:start position:0% +say yeah I understand okay so you're + + + align:start position:0% +say yeah I understand okay so you're +used to orbitals and it's perfectly + + align:start position:0% +used to orbitals and it's perfectly + + + align:start position:0% +used to orbitals and it's perfectly +reasonable because for hydrogen we have + + align:start position:0% +reasonable because for hydrogen we have + + + align:start position:0% +reasonable because for hydrogen we have +orbitals and there's only one orbital + + align:start position:0% +orbitals and there's only one orbital + + + align:start position:0% +orbitals and there's only one orbital +and it could have either spin we don't + + align:start position:0% +and it could have either spin we don't + + + align:start position:0% +and it could have either spin we don't +mess with that now we're going to talk + + align:start position:0% +mess with that now we're going to talk + + + align:start position:0% +mess with that now we're going to talk +about spindles and that's just the + + align:start position:0% +about spindles and that's just the + + + align:start position:0% +about spindles and that's just the +combination of the name of the orbital + + align:start position:0% +combination of the name of the orbital + + + align:start position:0% +combination of the name of the orbital +with whether the spin is up or down and + + align:start position:0% +with whether the spin is up or down and + + + align:start position:0% +with whether the spin is up or down and +the reason for this is it's easier to do + + align:start position:0% +the reason for this is it's easier to do + + + align:start position:0% +the reason for this is it's easier to do +the algebra and the reason the algebra + + align:start position:0% +the algebra and the reason the algebra + + + align:start position:0% +the algebra and the reason the algebra +is it's initially harder to do the + + align:start position:0% +is it's initially harder to do the + + + align:start position:0% +is it's initially harder to do the +algebra because there certainly certain + + align:start position:0% +algebra because there certainly certain + + + align:start position:0% +algebra because there certainly certain +selection rules and stuff like that but + + align:start position:0% +selection rules and stuff like that but + + + align:start position:0% +selection rules and stuff like that but +once you know how to do it you do the + + align:start position:0% +once you know how to do it you do the + + + align:start position:0% +once you know how to do it you do the +algebra and then all of a sudden + + align:start position:0% +algebra and then all of a sudden + + + align:start position:0% +algebra and then all of a sudden +everything pops out in a very useful + + align:start position:0% +everything pops out in a very useful + + + align:start position:0% +everything pops out in a very useful +form okay so the stick diagrams are very + + align:start position:0% +form okay so the stick diagrams are very + + + align:start position:0% +form okay so the stick diagrams are very +important but now I'm specifying the + + align:start position:0% +important but now I'm specifying the + + + align:start position:0% +important but now I'm specifying the +stick diagrams as spin orbitals rather + + align:start position:0% +stick diagrams as spin orbitals rather + + + align:start position:0% +stick diagrams as spin orbitals rather +than orbitals now another point there + + align:start position:0% +than orbitals now another point there + + + align:start position:0% +than orbitals now another point there +are rules for how so we the number of + + align:start position:0% +are rules for how so we the number of + + + align:start position:0% +are rules for how so we the number of +spin orbitals different between the left + + align:start position:0% +spin orbitals different between the left + + + align:start position:0% +spin orbitals different between the left +hand side and the right hand side of a + + align:start position:0% +hand side and the right hand side of a + + + align:start position:0% +hand side and the right hand side of a +matrix element there are rules that are + + align:start position:0% +matrix element there are rules that are + + + align:start position:0% +matrix element there are rules that are +easily described and so for every kind + + align:start position:0% +easily described and so for every kind + + + align:start position:0% +easily described and so for every kind +of orbital an orbital that has that is a + + align:start position:0% +of orbital an orbital that has that is a + + + align:start position:0% +of orbital an orbital that has that is a +scalar that doesn't doesn't depend on + + align:start position:0% +scalar that doesn't doesn't depend on + + + align:start position:0% +scalar that doesn't doesn't depend on +quantum numbers that has a selectable + + align:start position:0% +quantum numbers that has a selectable + + + align:start position:0% +quantum numbers that has a selectable +Delta a so of 0 and for something like a + + align:start position:0% +Delta a so of 0 and for something like a + + + align:start position:0% +Delta a so of 0 and for something like a +one electron operator that has a + + align:start position:0% +one electron operator that has a + + + align:start position:0% +one electron operator that has a +selection rule Delta at spin orbit of + + align:start position:0% +selection rule Delta at spin orbit of + + + align:start position:0% +selection rule Delta at spin orbit of +spin orbital of 1 and 0 and then we have + + align:start position:0% +spin orbital of 1 and 0 and then we have + + + align:start position:0% +spin orbital of 1 and 0 and then we have +our friend 1 over R IJ that has a + + align:start position:0% +our friend 1 over R IJ that has a + + + align:start position:0% +our friend 1 over R IJ that has a +selection rule Delta spin orbital of 2 1 + + align:start position:0% +selection rule Delta spin orbital of 2 1 + + + align:start position:0% +selection rule Delta spin orbital of 2 1 +and 0 and the + + align:start position:0% +and 0 and the + + + align:start position:0% +and 0 and the +for each something you work out and then + + align:start position:0% +for each something you work out and then + + + align:start position:0% +for each something you work out and then +you know how to do it and I'm going to + + align:start position:0% +you know how to do it and I'm going to + + + align:start position:0% +you know how to do it and I'm going to +try to give you just a little bit of a + + align:start position:0% +try to give you just a little bit of a + + + align:start position:0% +try to give you just a little bit of a +taste of this okay so we've already + + align:start position:0% +taste of this okay so we've already + + + align:start position:0% +taste of this okay so we've already +looked at something like this but we did + + align:start position:0% +looked at something like this but we did + + + align:start position:0% +looked at something like this but we did +we use a slightly different notation so + + align:start position:0% +we use a slightly different notation so + + + align:start position:0% +we use a slightly different notation so +I'm going to go back and we have 1s + + align:start position:0% +I'm going to go back and we have 1s + + + align:start position:0% +I'm going to go back and we have 1s +alpha 1 s beta 2 s alpha 2 s beta and so + + align:start position:0% +alpha 1 s beta 2 s alpha 2 s beta and so + + + align:start position:0% +alpha 1 s beta 2 s alpha 2 s beta and so +for the ground state of helium 1 s + + align:start position:0% +for the ground state of helium 1 s + + + align:start position:0% +for the ground state of helium 1 s +squared and we would do this and I mean + + align:start position:0% +squared and we would do this and I mean + + + align:start position:0% +squared and we would do this and I mean +the stick diagrams are great because + + align:start position:0% +the stick diagrams are great because + + + align:start position:0% +the stick diagrams are great because +it's it's easier to see on a picture + + align:start position:0% +it's it's easier to see on a picture + + + align:start position:0% +it's it's easier to see on a picture +what are the weather who are the actors + + align:start position:0% +what are the weather who are the actors + + + align:start position:0% +what are the weather who are the actors +in have I am I included all of them or + + align:start position:0% +in have I am I included all of them or + + + align:start position:0% +in have I am I included all of them or +if I'm left something out and so now we + + align:start position:0% +if I'm left something out and so now we + + + align:start position:0% +if I'm left something out and so now we +were interested in the stick diagram for + + align:start position:0% +were interested in the stick diagram for + + + align:start position:0% +were interested in the stick diagram for +the 1 s 2 s configuration and there are + + align:start position:0% +the 1 s 2 s configuration and there are + + + align:start position:0% +the 1 s 2 s configuration and there are +several kinds of 1 s 2 s configurations + + align:start position:0% +several kinds of 1 s 2 s configurations + + + align:start position:0% +several kinds of 1 s 2 s configurations +depending on what the alpha beta are so + + align:start position:0% +depending on what the alpha beta are so + + + align:start position:0% +depending on what the alpha beta are so +we have 1 s alpha 2 s alpha and we have + + align:start position:0% + + + + align:start position:0% + +1 s alpha 2 s beta 1 s beta 2 s alpha 2 + + align:start position:0% +1 s alpha 2 s beta 1 s beta 2 s alpha 2 + + + align:start position:0% +1 s alpha 2 s beta 1 s beta 2 s alpha 2 +s alpha minus beta 2 s data so there's + + align:start position:0% +s alpha minus beta 2 s data so there's + + + align:start position:0% +s alpha minus beta 2 s data so there's +four guys and we can put our arrows on + + align:start position:0% +four guys and we can put our arrows on + + + align:start position:0% +four guys and we can put our arrows on +these things and we we know everything + + align:start position:0% +these things and we we know everything + + + align:start position:0% +these things and we we know everything +we need to know about these guys we + + align:start position:0% +we need to know about these guys we + + + align:start position:0% +we need to know about these guys we +tells us what to do + + align:start position:0% + + + + align:start position:0% + +well when we do this + + align:start position:0% + + + + align:start position:0% + +the diagonal matrix elements of the + + align:start position:0% +the diagonal matrix elements of the + + + align:start position:0% +the diagonal matrix elements of the +Hamiltonian the one over R IJ + + align:start position:0% +Hamiltonian the one over R IJ + + + align:start position:0% +Hamiltonian the one over R IJ +Hamiltonian can be expressed and we use + + align:start position:0% +Hamiltonian can be expressed and we use + + + align:start position:0% +Hamiltonian can be expressed and we use +this notation J tilde minus K tilde so + + align:start position:0% +this notation J tilde minus K tilde so + + + align:start position:0% +this notation J tilde minus K tilde so +for every two-electron thing we're going + + align:start position:0% +for every two-electron thing we're going + + + align:start position:0% +for every two-electron thing we're going +to get this kind of now these are simple + + align:start position:0% +to get this kind of now these are simple + + + align:start position:0% +to get this kind of now these are simple +integrals and some of them are zero + + align:start position:0% +integrals and some of them are zero + + + align:start position:0% +integrals and some of them are zero +because this doesn't operate on spins + + align:start position:0% +because this doesn't operate on spins + + + align:start position:0% +because this doesn't operate on spins +and so the if you if you had a 1s alpha + + align:start position:0% +and so the if you if you had a 1s alpha + + + align:start position:0% +and so the if you if you had a 1s alpha +2 s beta 1 R IJ 1 s beta 2 s alpha then + + align:start position:0% +2 s beta 1 R IJ 1 s beta 2 s alpha then + + + align:start position:0% +2 s beta 1 R IJ 1 s beta 2 s alpha then +the 1s alpha with the one s beta is 0 + + align:start position:0% +the 1s alpha with the one s beta is 0 + + + align:start position:0% +the 1s alpha with the one s beta is 0 +the 1s alpha with the 2's alpha is not 0 + + align:start position:0% +the 1s alpha with the 2's alpha is not 0 + + + align:start position:0% +the 1s alpha with the 2's alpha is not 0 +etc there are all sorts of stuff but + + align:start position:0% +etc there are all sorts of stuff but + + + align:start position:0% +etc there are all sorts of stuff but +this tilde notation says well this is + + align:start position:0% +this tilde notation says well this is + + + align:start position:0% +this tilde notation says well this is +what we start with and we have to + + align:start position:0% +what we start with and we have to + + + align:start position:0% +what we start with and we have to +convert it into things that really + + align:start position:0% +convert it into things that really + + + align:start position:0% +convert it into things that really +matter so the operation of removing the + + align:start position:0% +matter so the operation of removing the + + + align:start position:0% +matter so the operation of removing the +tilde requires a little bit of work a + + align:start position:0% +tilde requires a little bit of work a + + + align:start position:0% +tilde requires a little bit of work a +little bit of thought and that's why my + + align:start position:0% +little bit of thought and that's why my + + + align:start position:0% +little bit of thought and that's why my +notes are crafted because I can't + + align:start position:0% +notes are crafted because I can't + + + align:start position:0% +notes are crafted because I can't +explain it well enough to really teach + + align:start position:0% +explain it well enough to really teach + + + align:start position:0% +explain it well enough to really teach +this but let's just so + + align:start position:0% + + + + align:start position:0% + +when when we do the 1 s squared the j1 s + + align:start position:0% +when when we do the 1 s squared the j1 s + + + align:start position:0% +when when we do the 1 s squared the j1 s +squared tilde is equal to the j1 s + + align:start position:0% +squared tilde is equal to the j1 s + + + align:start position:0% +squared tilde is equal to the j1 s +squared because the spins take care of + + align:start position:0% +squared because the spins take care of + + + align:start position:0% +squared because the spins take care of +themselves but K tilde 1 s squared is + + align:start position:0% +themselves but K tilde 1 s squared is + + + align:start position:0% +themselves but K tilde 1 s squared is +equal to 0 because we when we we do 1 s + + align:start position:0% +equal to 0 because we when we we do 1 s + + + align:start position:0% +equal to 0 because we when we we do 1 s +squared we have an alpha with an alpha + + align:start position:0% +squared we have an alpha with an alpha + + + align:start position:0% +squared we have an alpha with an alpha +for the J term and an alpha with the + + align:start position:0% +for the J term and an alpha with the + + + align:start position:0% +for the J term and an alpha with the +beta for the K term and alpha with beta + + align:start position:0% +beta for the K term and alpha with beta + + + align:start position:0% +beta for the K term and alpha with beta +is 0 because the operator cannot change + + align:start position:0% +is 0 because the operator cannot change + + + align:start position:0% +is 0 because the operator cannot change +alpha and two beta ok so but so this + + align:start position:0% +alpha and two beta ok so but so this + + + align:start position:0% +alpha and two beta ok so but so this +tilde notation is a convenient thing + + align:start position:0% +tilde notation is a convenient thing + + + align:start position:0% +tilde notation is a convenient thing +because you can use any Slater + + align:start position:0% +because you can use any Slater + + + align:start position:0% +because you can use any Slater +determinant and you can express it in + + align:start position:0% +determinant and you can express it in + + + align:start position:0% +determinant and you can express it in +terms of J's and KS and the sign comes + + align:start position:0% +terms of J's and KS and the sign comes + + + align:start position:0% +terms of J's and KS and the sign comes +from switching the order of the orbitals + + align:start position:0% +from switching the order of the orbitals + + + align:start position:0% +from switching the order of the orbitals +that's how the determinants work and and + + align:start position:0% +that's how the determinants work and and + + + align:start position:0% +that's how the determinants work and and +so you could your you're going to see a + + align:start position:0% +so you could your you're going to see a + + + align:start position:0% +so you could your you're going to see a +whole bunch of stuff but removing the + + align:start position:0% +whole bunch of stuff but removing the + + + align:start position:0% +whole bunch of stuff but removing the +tilde is the tricky business ok now when + + align:start position:0% +tilde is the tricky business ok now when + + + align:start position:0% +tilde is the tricky business ok now when +you get a problem where you have a + + align:start position:0% +you get a problem where you have a + + + align:start position:0% +you get a problem where you have a +configuration where a single Slater is + + align:start position:0% +configuration where a single Slater is + + + align:start position:0% +configuration where a single Slater is +not sufficient in other words in order + + align:start position:0% +not sufficient in other words in order + + + align:start position:0% +not sufficient in other words in order +to make an eigenstate of s squared or SZ + + align:start position:0% +to make an eigenstate of s squared or SZ + + + align:start position:0% +to make an eigenstate of s squared or SZ +you sometimes need two or more Slater's + + align:start position:0% +you sometimes need two or more Slater's + + + align:start position:0% +you sometimes need two or more Slater's +and you have to use a particular linear + + align:start position:0% +and you have to use a particular linear + + + align:start position:0% +and you have to use a particular linear +combination of them to get the right + + align:start position:0% +combination of them to get the right + + + align:start position:0% +combination of them to get the right +value of s and SC and then what happens + + align:start position:0% +value of s and SC and then what happens + + + align:start position:0% +value of s and SC and then what happens +is you're looking at matrix + + align:start position:0% +is you're looking at matrix + + + align:start position:0% +is you're looking at matrix +elements between of the 1 over RI J + + align:start position:0% +elements between of the 1 over RI J + + + align:start position:0% +elements between of the 1 over RI J +operator between Slater's now this is a + + align:start position:0% +operator between Slater's now this is a + + + align:start position:0% +operator between Slater's now this is a +headache and you know I could talk until + + align:start position:0% +headache and you know I could talk until + + + align:start position:0% +headache and you know I could talk until +I'm blue in the face and I cannot make + + align:start position:0% +I'm blue in the face and I cannot make + + + align:start position:0% +I'm blue in the face and I cannot make +it clear that how to do this because + + align:start position:0% +it clear that how to do this because + + + align:start position:0% +it clear that how to do this because +it's just awful but you know some things + + align:start position:0% +it's just awful but you know some things + + + align:start position:0% +it's just awful but you know some things +in life are worth suffering for and so + + align:start position:0% + + + + align:start position:0% + +anyway in the 1 s 2 s situation when you + + align:start position:0% +anyway in the 1 s 2 s situation when you + + + align:start position:0% +anyway in the 1 s 2 s situation when you +do everything right you get this is just + + align:start position:0% +do everything right you get this is just + + + align:start position:0% +do everything right you get this is just +a general notation for a 2 electron wave + + align:start position:0% +a general notation for a 2 electron wave + + + align:start position:0% +a general notation for a 2 electron wave +function 1 over R 1 to 2 so these guys + + align:start position:0% +function 1 over R 1 to 2 so these guys + + + align:start position:0% +function 1 over R 1 to 2 so these guys +are eigenfunctions of s squared of SC + + align:start position:0% +are eigenfunctions of s squared of SC + + + align:start position:0% +are eigenfunctions of s squared of SC +and when you do that you get 1/2 times 2 + + align:start position:0% +and when you do that you get 1/2 times 2 + + + align:start position:0% +and when you do that you get 1/2 times 2 +J 1 s 2 s minus or plus 2 K 1 s 2 s + + align:start position:0% +J 1 s 2 s minus or plus 2 K 1 s 2 s + + + align:start position:0% +J 1 s 2 s minus or plus 2 K 1 s 2 s +remember when you have mismatched alpha + + align:start position:0% +remember when you have mismatched alpha + + + align:start position:0% +remember when you have mismatched alpha +and beta the k's are 0 but when you have + + align:start position:0% +and beta the k's are 0 but when you have + + + align:start position:0% +and beta the k's are 0 but when you have +k the 1 over r IJ matrix elements + + align:start position:0% +k the 1 over r IJ matrix elements + + + align:start position:0% +k the 1 over r IJ matrix elements +between two slater's you could fix that + + align:start position:0% +between two slater's you could fix that + + + align:start position:0% +between two slater's you could fix that +and so this is this is why it's so hard + + align:start position:0% +and so this is this is why it's so hard + + + align:start position:0% +and so this is this is why it's so hard +to explain because you know yes I'm not + + align:start position:0% +to explain because you know yes I'm not + + + align:start position:0% +to explain because you know yes I'm not +even going to apologize anymore + + align:start position:0% +even going to apologize anymore + + + align:start position:0% +even going to apologize anymore +ok so this is what you do and the notes + + align:start position:0% +ok so this is what you do and the notes + + + align:start position:0% +ok so this is what you do and the notes +are pretty clear about how to do them + + align:start position:0% +are pretty clear about how to do them + + + align:start position:0% +are pretty clear about how to do them +and what the problems are + + align:start position:0% +and what the problems are + + + align:start position:0% +and what the problems are +but lecturing on it would be a little + + align:start position:0% +but lecturing on it would be a little + + + align:start position:0% +but lecturing on it would be a little +bit hard ok so now what are we going to + + align:start position:0% +bit hard ok so now what are we going to + + + align:start position:0% +bit hard ok so now what are we going to +do with it well we'd like qualitative + + align:start position:0% + + + + align:start position:0% + +stuff and interpretive stuff + + align:start position:0% + + + + align:start position:0% + +okay qualitative is one's rules now if + + align:start position:0% +okay qualitative is one's rules now if + + + align:start position:0% +okay qualitative is one's rules now if +you looked at a hundred textbooks + + align:start position:0% +you looked at a hundred textbooks + + + align:start position:0% +you looked at a hundred textbooks +I think 95 of them will have Quinn's + + align:start position:0% +I think 95 of them will have Quinn's + + + align:start position:0% +I think 95 of them will have Quinn's +rules wrong you're never going to make + + align:start position:0% +rules wrong you're never going to make + + + align:start position:0% +rules wrong you're never going to make +that mistake and interpretive well we + + align:start position:0% +that mistake and interpretive well we + + + align:start position:0% +that mistake and interpretive well we +want to know the trends of things and we + + align:start position:0% +want to know the trends of things and we + + + align:start position:0% +want to know the trends of things and we +want to be able to do something like + + align:start position:0% +want to be able to do something like + + + align:start position:0% +want to be able to do something like +what you did in freshman chemistry + + align:start position:0% +what you did in freshman chemistry + + + align:start position:0% +what you did in freshman chemistry +shielding now you probably memorize some + + align:start position:0% +shielding now you probably memorize some + + + align:start position:0% +shielding now you probably memorize some +rules about what shields what and but + + align:start position:0% +rules about what shields what and but + + + align:start position:0% +rules about what shields what and but +I'm gonna give you a little bit more + + align:start position:0% +I'm gonna give you a little bit more + + + align:start position:0% +I'm gonna give you a little bit more +insight into that so we're going to talk + + align:start position:0% +insight into that so we're going to talk + + + align:start position:0% +insight into that so we're going to talk +about this for the rest of the lecture + + align:start position:0% + + + + align:start position:0% + +okay so + + align:start position:0% + + + + align:start position:0% + +you specify configuration and this + + align:start position:0% +you specify configuration and this + + + align:start position:0% +you specify configuration and this +configuration might be two electrons to + + align:start position:0% +configuration might be two electrons to + + + align:start position:0% +configuration might be two electrons to +spin orbitals to orbital sub Z or 3 or + + align:start position:0% +spin orbitals to orbital sub Z or 3 or + + + align:start position:0% +spin orbitals to orbital sub Z or 3 or +10 and you know often when you specify + + align:start position:0% +10 and you know often when you specify + + + align:start position:0% +10 and you know often when you specify +the occupied orbitals you neglect the + + align:start position:0% +the occupied orbitals you neglect the + + + align:start position:0% +the occupied orbitals you neglect the +filled ones which is nice because you + + align:start position:0% +filled ones which is nice because you + + + align:start position:0% +filled ones which is nice because you +have fewer things to worry about + + align:start position:0% +have fewer things to worry about + + + align:start position:0% +have fewer things to worry about +because filled orbitals have spin zero + + align:start position:0% +because filled orbitals have spin zero + + + align:start position:0% +because filled orbitals have spin zero +and you don't have to do anything there + + align:start position:0% +and you don't have to do anything there + + + align:start position:0% +and you don't have to do anything there +automatically and I Sigma tries and they + + align:start position:0% +automatically and I Sigma tries and they + + + align:start position:0% +automatically and I Sigma tries and they +basically act as a charge distribution + + align:start position:0% +basically act as a charge distribution + + + align:start position:0% +basically act as a charge distribution +in the core that is sampled by the + + align:start position:0% +in the core that is sampled by the + + + align:start position:0% +in the core that is sampled by the +electrons outside and so you need some + + align:start position:0% +electrons outside and so you need some + + + align:start position:0% +electrons outside and so you need some +sort of a set of rules for how do that + + align:start position:0% +sort of a set of rules for how do that + + + align:start position:0% +sort of a set of rules for how do that +how does that work and that's shielding + + align:start position:0% +how does that work and that's shielding + + + align:start position:0% +how does that work and that's shielding +but okay so we first we specify a + + align:start position:0% +but okay so we first we specify a + + + align:start position:0% +but okay so we first we specify a +configuration and you also learned in + + align:start position:0% +configuration and you also learned in + + + align:start position:0% +configuration and you also learned in +high school probably how to determine + + align:start position:0% +high school probably how to determine + + + align:start position:0% +high school probably how to determine +the elf s J terms the result from this + + align:start position:0% +the elf s J terms the result from this + + + align:start position:0% +the elf s J terms the result from this +configuration by some magical crossing + + align:start position:0% +configuration by some magical crossing + + + align:start position:0% +configuration by some magical crossing +out of boxes and if you didn't I'm glad + + align:start position:0% +out of boxes and if you didn't I'm glad + + + align:start position:0% +out of boxes and if you didn't I'm glad +because it would have just clouded your + + align:start position:0% +because it would have just clouded your + + + align:start position:0% +because it would have just clouded your +mind and caused earlier insanity then + + align:start position:0% +mind and caused earlier insanity then + + + align:start position:0% +mind and caused earlier insanity then +you know that MIT causes so anyway so we + + align:start position:0% +you know that MIT causes so anyway so we + + + align:start position:0% +you know that MIT causes so anyway so we +have orbital angular momentum and we can + + align:start position:0% +have orbital angular momentum and we can + + + align:start position:0% +have orbital angular momentum and we can +add the orbital angular momenta of the + + align:start position:0% +add the orbital angular momenta of the + + + align:start position:0% +add the orbital angular momenta of the +electrons and following certain rules + + align:start position:0% +electrons and following certain rules + + + align:start position:0% +electrons and following certain rules +and we have spin angular momenta and J + + align:start position:0% +and we have spin angular momenta and J + + + align:start position:0% +and we have spin angular momenta and J +is equal to a vector sum of LNS and we + + align:start position:0% +is equal to a vector sum of LNS and we + + + align:start position:0% +is equal to a vector sum of LNS and we +say we have an LS term like triplet P + + align:start position:0% +say we have an LS term like triplet P + + + align:start position:0% +say we have an LS term like triplet P +and it could have J is equal to L plus L + + align:start position:0% +and it could have J is equal to L plus L + + + align:start position:0% +and it could have J is equal to L plus L +plus s L plus s minus 1 down to l minus + + align:start position:0% +plus s L plus s minus 1 down to l minus + + + align:start position:0% +plus s L plus s minus 1 down to l minus +s absolute value these are the possible + + align:start position:0% +s absolute value these are the possible + + + align:start position:0% +s absolute value these are the possible +J's + + align:start position:0% +J's + + + align:start position:0% +J's +and so hones rules is all about of all + + align:start position:0% +and so hones rules is all about of all + + + align:start position:0% +and so hones rules is all about of all +of the states that belong to a + + align:start position:0% +of the states that belong to a + + + align:start position:0% +of the states that belong to a +particular configuration which one is + + align:start position:0% +particular configuration which one is + + + align:start position:0% +particular configuration which one is +the lowest one which one not the second + + align:start position:0% +the lowest one which one not the second + + + align:start position:0% +the lowest one which one not the second +lowest which one is the lowest and why + + align:start position:0% +lowest which one is the lowest and why + + + align:start position:0% +lowest which one is the lowest and why +do we care because in statistical + + align:start position:0% +do we care because in statistical + + + align:start position:0% +do we care because in statistical +mechanics everything is dominated by the + + align:start position:0% +mechanics everything is dominated by the + + + align:start position:0% +mechanics everything is dominated by the +lowest energy state and so if you can + + align:start position:0% +lowest energy state and so if you can + + + align:start position:0% +lowest energy state and so if you can +figure out what is the lowest energy + + align:start position:0% +figure out what is the lowest energy + + + align:start position:0% +figure out what is the lowest energy +state you basically got as much as most + + align:start position:0% +state you basically got as much as most + + + align:start position:0% +state you basically got as much as most +people are going to want so you want to + + align:start position:0% +people are going to want so you want to + + + align:start position:0% +people are going to want so you want to +know what is what are L s and J for the + + align:start position:0% +know what is what are L s and J for the + + + align:start position:0% +know what is what are L s and J for the +lowest energy state of a configuration + + align:start position:0% +lowest energy state of a configuration + + + align:start position:0% +lowest energy state of a configuration +configurations are typically far apart + + align:start position:0% +configurations are typically far apart + + + align:start position:0% +configurations are typically far apart +in energy so if you know what the lowest + + align:start position:0% +in energy so if you know what the lowest + + + align:start position:0% +in energy so if you know what the lowest +energy configuration is and the lowest + + align:start position:0% +energy configuration is and the lowest + + + align:start position:0% +energy configuration is and the lowest +energy state of it as far as your + + align:start position:0% +energy state of it as far as your + + + align:start position:0% +energy state of it as far as your +friends the specific mechanician 's you + + align:start position:0% +friends the specific mechanician 's you + + + align:start position:0% +friends the specific mechanician 's you +can tell them how to write their + + align:start position:0% +can tell them how to write their + + + align:start position:0% +can tell them how to write their +partition functions and the rest is + + align:start position:0% +partition functions and the rest is + + + align:start position:0% +partition functions and the rest is +details and mostly you don't want + + align:start position:0% +details and mostly you don't want + + + align:start position:0% +details and mostly you don't want +details and if your friends tell you + + align:start position:0% +details and if your friends tell you + + + align:start position:0% +details and if your friends tell you +they want details well you tell them + + align:start position:0% +they want details well you tell them + + + align:start position:0% +they want details well you tell them +this is what you have to do but it's no + + align:start position:0% +this is what you have to do but it's no + + + align:start position:0% +this is what you have to do but it's no +simple three quince rules okay so whose + + align:start position:0% +simple three quince rules okay so whose + + + align:start position:0% +simple three quince rules okay so whose +rules you look at all of the lsj states + + align:start position:0% +rules you look at all of the lsj states + + + align:start position:0% +rules you look at all of the lsj states +that are possible from a particular + + align:start position:0% +that are possible from a particular + + + align:start position:0% +that are possible from a particular +configuration and you can use the + + align:start position:0% +configuration and you can use the + + + align:start position:0% +configuration and you can use the +crossing out of MLMs boxes if you want + + align:start position:0% +crossing out of MLMs boxes if you want + + + align:start position:0% +crossing out of MLMs boxes if you want +and I could tell you why you would do + + align:start position:0% +and I could tell you why you would do + + + align:start position:0% +and I could tell you why you would do +that but I don't want to cause insanity + + align:start position:0% +that but I don't want to cause insanity + + + align:start position:0% +that but I don't want to cause insanity +at this stage either but you know I'm an + + align:start position:0% +at this stage either but you know I'm an + + + align:start position:0% +at this stage either but you know I'm an +expert at that and you can also use + + align:start position:0% +expert at that and you can also use + + + align:start position:0% +expert at that and you can also use +lowering operators to generate all the + + align:start position:0% +lowering operators to generate all the + + + align:start position:0% +lowering operators to generate all the +states once you know stuff okay so once + + align:start position:0% +states once you know stuff okay so once + + + align:start position:0% +states once you know stuff okay so once +you know all the states horn says which + + align:start position:0% +you know all the states horn says which + + + align:start position:0% +you know all the states horn says which +one of these has the largest S which one + + align:start position:0% +one of these has the largest S which one + + + align:start position:0% +one of these has the largest S which one +that's easy to know and for example if + + align:start position:0% +that's easy to know and for example if + + + align:start position:0% +that's easy to know and for example if +you had 2p squared you're going to get + + align:start position:0% + + + + align:start position:0% + +sing + + align:start position:0% +sing + + + align:start position:0% +sing +d triplet P and Sigma s and well here's + + align:start position:0% +d triplet P and Sigma s and well here's + + + align:start position:0% +d triplet P and Sigma s and well here's +the triplet that has a large tes + + align:start position:0% +the triplet that has a large tes + + + align:start position:0% +the triplet that has a large tes +so the triplet P is the lowest energy + + align:start position:0% +so the triplet P is the lowest energy + + + align:start position:0% +so the triplet P is the lowest energy +state now if there if there were + + align:start position:0% +state now if there if there were + + + align:start position:0% +state now if there if there were +multiple Triplets as there would be say + + align:start position:0% +multiple Triplets as there would be say + + + align:start position:0% +multiple Triplets as there would be say +4 2 P 3 D then you'd have to decide + + align:start position:0% +4 2 P 3 D then you'd have to decide + + + align:start position:0% +4 2 P 3 D then you'd have to decide +which of those triplets is the lowest + + align:start position:0% +which of those triplets is the lowest + + + align:start position:0% +which of those triplets is the lowest +and all you care about all you're + + align:start position:0% +and all you care about all you're + + + align:start position:0% +and all you care about all you're +allowed to say is which one is the + + align:start position:0% +allowed to say is which one is the + + + align:start position:0% +allowed to say is which one is the +lowest and it's the one with the maximum + + align:start position:0% +lowest and it's the one with the maximum + + + align:start position:0% +lowest and it's the one with the maximum +L and then the last step is which what + + align:start position:0% +L and then the last step is which what + + + align:start position:0% +L and then the last step is which what +is the lowest J for that LS state and + + align:start position:0% +is the lowest J for that LS state and + + + align:start position:0% +is the lowest J for that LS state and +that's kind of cute because ya so you + + align:start position:0% +that's kind of cute because ya so you + + + align:start position:0% +that's kind of cute because ya so you +have the P shellers there's for a a PL + + align:start position:0% +have the P shellers there's for a a PL + + + align:start position:0% +have the P shellers there's for a a PL +you can have 6 P orbitals to fill the + + align:start position:0% +you can have 6 P orbitals to fill the + + + align:start position:0% +you can have 6 P orbitals to fill the +shelves 1 alpha 1 beta 2 elf I was 0 + + align:start position:0% +shelves 1 alpha 1 beta 2 elf I was 0 + + + align:start position:0% +shelves 1 alpha 1 beta 2 elf I was 0 +alpha 0 beta etc so the degeneracy of a + + align:start position:0% +alpha 0 beta etc so the degeneracy of a + + + align:start position:0% +alpha 0 beta etc so the degeneracy of a +p electra p orbital is 6 if you have P + + align:start position:0% +p electra p orbital is 6 if you have P + + + align:start position:0% +p electra p orbital is 6 if you have P +to n where n is less than or equal less + + align:start position:0% +to n where n is less than or equal less + + + align:start position:0% +to n where n is less than or equal less +than 3 you have a less than half filled + + align:start position:0% +than 3 you have a less than half filled + + + align:start position:0% +than 3 you have a less than half filled +shell and then lowest is J equal L minus + + align:start position:0% +shell and then lowest is J equal L minus + + + align:start position:0% +shell and then lowest is J equal L minus +s absolute value and if n is greater + + align:start position:0% +s absolute value and if n is greater + + + align:start position:0% +s absolute value and if n is greater +than 3 you have the lowest being the + + align:start position:0% +than 3 you have the lowest being the + + + align:start position:0% +than 3 you have the lowest being the +highest possible value J + + align:start position:0% +highest possible value J + + + align:start position:0% +highest possible value J +is equal to L plus s so for L and + + align:start position:0% +is equal to L plus s so for L and + + + align:start position:0% +is equal to L plus s so for L and +greater than three and now when you have + + align:start position:0% +greater than three and now when you have + + + align:start position:0% +greater than three and now when you have +a half-filled shell the lowest state is + + align:start position:0% + + + + align:start position:0% + +it's usually an S state with the maximum + + align:start position:0% +it's usually an S state with the maximum + + + align:start position:0% +it's usually an S state with the maximum +spin but it doesn't matter that there's + + align:start position:0% +spin but it doesn't matter that there's + + + align:start position:0% +spin but it doesn't matter that there's +when you have a less than or more than + + align:start position:0% +when you have a less than or more than + + + align:start position:0% +when you have a less than or more than +half filled shell you have generally a + + align:start position:0% +half filled shell you have generally a + + + align:start position:0% +half filled shell you have generally a +state with orbital angular momentum not + + align:start position:0% +state with orbital angular momentum not + + + align:start position:0% +state with orbital angular momentum not +equal to 0 and you have spin orbit + + align:start position:0% +equal to 0 and you have spin orbit + + + align:start position:0% +equal to 0 and you have spin orbit +splitting of that and so you do want to + + align:start position:0% +splitting of that and so you do want to + + + align:start position:0% +splitting of that and so you do want to +care which what is the lowest J but when + + align:start position:0% +care which what is the lowest J but when + + + align:start position:0% +care which what is the lowest J but when +n is equal to 3 the lowest state it's + + align:start position:0% +n is equal to 3 the lowest state it's + + + align:start position:0% +n is equal to 3 the lowest state it's +usually at a state it doesn't have a + + align:start position:0% +usually at a state it doesn't have a + + + align:start position:0% +usually at a state it doesn't have a +spin orbit splitting and it just has one + + align:start position:0% +spin orbit splitting and it just has one + + + align:start position:0% +spin orbit splitting and it just has one +value of J which is whatever the spin is + + align:start position:0% +value of J which is whatever the spin is + + + align:start position:0% +value of J which is whatever the spin is +okay so one's rule tell you how to + + align:start position:0% +okay so one's rule tell you how to + + + align:start position:0% +okay so one's rule tell you how to +identify without knowing beans what is + + align:start position:0% +identify without knowing beans what is + + + align:start position:0% +identify without knowing beans what is +the lowest energy state and it's never + + align:start position:0% +the lowest energy state and it's never + + + align:start position:0% +the lowest energy state and it's never +wrong and well maybe sometimes wrong but + + align:start position:0% +wrong and well maybe sometimes wrong but + + + align:start position:0% +wrong and well maybe sometimes wrong but +that's because of one of my things where + + align:start position:0% +that's because of one of my things where + + + align:start position:0% +that's because of one of my things where +you have a perturbation between states + + align:start position:0% +you have a perturbation between states + + + align:start position:0% +you have a perturbation between states +belonging to do configurations but + + align:start position:0% +belonging to do configurations but + + + align:start position:0% +belonging to do configurations but +people get really excited when they + + align:start position:0% +people get really excited when they + + + align:start position:0% +people get really excited when they +discover a violation of winds rules and + + align:start position:0% +discover a violation of winds rules and + + + align:start position:0% +discover a violation of winds rules and +it's just trivial so there's this ok and + + align:start position:0% +it's just trivial so there's this ok and + + + align:start position:0% +it's just trivial so there's this ok and +then what time is it I have a few + + align:start position:0% +then what time is it I have a few + + + align:start position:0% +then what time is it I have a few +minutes to talk about shielding and I + + align:start position:0% +minutes to talk about shielding and I + + + align:start position:0% +minutes to talk about shielding and I +will okay so we have a nucleus and it + + align:start position:0% +will okay so we have a nucleus and it + + + align:start position:0% +will okay so we have a nucleus and it +has a charge of Z their nucleus there's + + align:start position:0% +has a charge of Z their nucleus there's + + + align:start position:0% +has a charge of Z their nucleus there's +no electrons so the atomic number is the + + align:start position:0% +no electrons so the atomic number is the + + + align:start position:0% +no electrons so the atomic number is the +charge and then we have a filled shell + + align:start position:0% +charge and then we have a filled shell + + + align:start position:0% +charge and then we have a filled shell +around it + + align:start position:0% +around it + + + align:start position:0% +around it +it's spherically symmetric and so if we + + align:start position:0% +it's spherically symmetric and so if we + + + align:start position:0% +it's spherically symmetric and so if we +penetrate inside of it what we see + + align:start position:0% +penetrate inside of it what we see + + + align:start position:0% +penetrate inside of it what we see +suppose we penetrate inside to this + + align:start position:0% +suppose we penetrate inside to this + + + align:start position:0% +suppose we penetrate inside to this +point what we see is only the plus Z + + align:start position:0% +point what we see is only the plus Z + + + align:start position:0% +point what we see is only the plus Z +minus the number of electron + + align:start position:0% +minus the number of electron + + + align:start position:0% +minus the number of electron +inside this fear now if you took + + align:start position:0% +inside this fear now if you took + + + align:start position:0% +inside this fear now if you took +electricity and magnetism you can prove + + align:start position:0% +electricity and magnetism you can prove + + + align:start position:0% +electricity and magnetism you can prove +this if you didn't you can accept it and + + align:start position:0% +this if you didn't you can accept it and + + + align:start position:0% +this if you didn't you can accept it and +so outside the nucleus the charge is + + align:start position:0% +so outside the nucleus the charge is + + + align:start position:0% +so outside the nucleus the charge is +plus one because you have a neutral atom + + align:start position:0% +plus one because you have a neutral atom + + + align:start position:0% +plus one because you have a neutral atom +and and then when you penetrate inside + + align:start position:0% +and and then when you penetrate inside + + + align:start position:0% +and and then when you penetrate inside +this region of dense charge and all spin + + align:start position:0% +this region of dense charge and all spin + + + align:start position:0% +this region of dense charge and all spin +all of the spins are generally paired + + align:start position:0% +all of the spins are generally paired + + + align:start position:0% +all of the spins are generally paired +this is spherical and you you so what + + align:start position:0% +this is spherical and you you so what + + + align:start position:0% +this is spherical and you you so what +you end up seeing is Z effective as + + align:start position:0% +you end up seeing is Z effective as + + + align:start position:0% +you end up seeing is Z effective as +opposed to Z true and let's say here's + + align:start position:0% +opposed to Z true and let's say here's + + + align:start position:0% +opposed to Z true and let's say here's +our zero where this is zero and so + + align:start position:0% +our zero where this is zero and so + + + align:start position:0% +our zero where this is zero and so +beyond our zero the charge that you see + + align:start position:0% +beyond our zero the charge that you see + + + align:start position:0% +beyond our zero the charge that you see +is plus one at zero you see a charge of + + align:start position:0% +is plus one at zero you see a charge of + + + align:start position:0% +is plus one at zero you see a charge of +Z and so what ends up happening is you + + align:start position:0% +Z and so what ends up happening is you + + + align:start position:0% +Z and so what ends up happening is you +get at Z effective which is dependent on + + align:start position:0% +get at Z effective which is dependent on + + + align:start position:0% +get at Z effective which is dependent on +distance from the nucleus and it goes + + align:start position:0% +distance from the nucleus and it goes + + + align:start position:0% +distance from the nucleus and it goes +from the integer value that you know + + align:start position:0% +from the integer value that you know + + + align:start position:0% +from the integer value that you know +from the the atomic number down to one + + align:start position:0% +from the the atomic number down to one + + + align:start position:0% +from the the atomic number down to one +because you've taken one electron away + + align:start position:0% +because you've taken one electron away + + + align:start position:0% +because you've taken one electron away +from a neutral atom and taking it + + align:start position:0% +from a neutral atom and taking it + + + align:start position:0% +from a neutral atom and taking it +outside and now we have this wonderful + + align:start position:0% +outside and now we have this wonderful + + + align:start position:0% +outside and now we have this wonderful +thing called the centrifugal barrier so + + align:start position:0% +thing called the centrifugal barrier so + + + align:start position:0% +thing called the centrifugal barrier so +if we have a state that has a non zero + + align:start position:0% +if we have a state that has a non zero + + + align:start position:0% +if we have a state that has a non zero +value of L well if we have a state with + + align:start position:0% +value of L well if we have a state with + + + align:start position:0% +value of L well if we have a state with +a zero value of all it can penetrate all + + align:start position:0% +a zero value of all it can penetrate all + + + align:start position:0% +a zero value of all it can penetrate all +the way into the car to the nucleus and + + align:start position:0% +the way into the car to the nucleus and + + + align:start position:0% +the way into the car to the nucleus and +so that means that the shielding is less + + align:start position:0% +so that means that the shielding is less + + + align:start position:0% +so that means that the shielding is less +for s orbitals and now if we have a non + + align:start position:0% +for s orbitals and now if we have a non + + + align:start position:0% +for s orbitals and now if we have a non +zero L it can't get in so far and the + + align:start position:0% +zero L it can't get in so far and the + + + align:start position:0% +zero L it can't get in so far and the +larger the L is the less the less it can + + align:start position:0% +larger the L is the less the less it can + + + align:start position:0% +larger the L is the less the less it can +see this extra charge so High Elves are + + align:start position:0% +see this extra charge so High Elves are + + + align:start position:0% +see this extra charge so High Elves are +very well shielded low ELLs are not so + + align:start position:0% +very well shielded low ELLs are not so + + + align:start position:0% +very well shielded low ELLs are not so +well shielded and the shielding goes as + + align:start position:0% +well shielded and the shielding goes as + + + align:start position:0% +well shielded and the shielding goes as +most I mean s least shielded P less so + + align:start position:0% +most I mean s least shielded P less so + + + align:start position:0% +most I mean s least shielded P less so +on + + align:start position:0% +on + + + align:start position:0% +on +now there's some other interesting + + align:start position:0% +now there's some other interesting + + + align:start position:0% +now there's some other interesting +things which you know I hate to say this + + align:start position:0% +things which you know I hate to say this + + + align:start position:0% +things which you know I hate to say this +but comparing 511 1 or 511 to to the 309 + + align:start position:0% +but comparing 511 1 or 511 to to the 309 + + + align:start position:0% +but comparing 511 1 or 511 to to the 309 +1 there is this business of what happens + + align:start position:0% +1 there is this business of what happens + + + align:start position:0% +1 there is this business of what happens +when you start to so when you have you + + align:start position:0% +when you start to so when you have you + + + align:start position:0% +when you start to so when you have you +start with potassium and so you put an + + align:start position:0% +start with potassium and so you put an + + + align:start position:0% +start with potassium and so you put an +electron in the 4s not in the 3d orbital + + align:start position:0% +electron in the 4s not in the 3d orbital + + + align:start position:0% +electron in the 4s not in the 3d orbital +right why is that + + align:start position:0% + + + + align:start position:0% + +well the 4s sees the the the larger + + align:start position:0% +well the 4s sees the the the larger + + + align:start position:0% +well the 4s sees the the the larger +charge is less shielded so it goes in + + align:start position:0% +charge is less shielded so it goes in + + + align:start position:0% +charge is less shielded so it goes in +then when you go from potassium to + + align:start position:0% +then when you go from potassium to + + + align:start position:0% +then when you go from potassium to +calcium you put another electron in this + + align:start position:0% +calcium you put another electron in this + + + align:start position:0% +calcium you put another electron in this +and that's true so you for calcium you + + align:start position:0% +and that's true so you for calcium you + + + align:start position:0% +and that's true so you for calcium you +have a 4 s squared and 4s 3d is a higher + + align:start position:0% +have a 4 s squared and 4s 3d is a higher + + + align:start position:0% +have a 4 s squared and 4s 3d is a higher +lying state now you take an electron I'm + + align:start position:0% +lying state now you take an electron I'm + + + align:start position:0% +lying state now you take an electron I'm +cooking my my own goose if you take one + + align:start position:0% +cooking my my own goose if you take one + + + align:start position:0% +cooking my my own goose if you take one +of these electrons away this is not the + + align:start position:0% +of these electrons away this is not the + + + align:start position:0% +of these electrons away this is not the +way I wanted it to come out you end up + + align:start position:0% +way I wanted it to come out you end up + + + align:start position:0% +way I wanted it to come out you end up +having you find yourself in a 3d state + + align:start position:0% +having you find yourself in a 3d state + + + align:start position:0% +having you find yourself in a 3d state +because 3d penetrates a little bit under + + align:start position:0% +because 3d penetrates a little bit under + + + align:start position:0% +because 3d penetrates a little bit under +4s and you I can't do I can't explain it + + align:start position:0% +4s and you I can't do I can't explain it + + + align:start position:0% +4s and you I can't do I can't explain it +in a way that's gonna make sense I + + align:start position:0% +in a way that's gonna make sense I + + + align:start position:0% +in a way that's gonna make sense I +really wanted to because I I I care so + + align:start position:0% +really wanted to because I I I care so + + + align:start position:0% +really wanted to because I I I care so +much about these simple arguments but I + + align:start position:0% +much about these simple arguments but I + + + align:start position:0% +much about these simple arguments but I +I I will just be wasting your time so + + align:start position:0% +I I will just be wasting your time so + + + align:start position:0% +I I will just be wasting your time so +the order in which you fill orbitals + + align:start position:0% +the order in which you fill orbitals + + + align:start position:0% +the order in which you fill orbitals +comes out naturally different from the + + align:start position:0% +comes out naturally different from the + + + align:start position:0% +comes out naturally different from the +Orval order in which you removal + + align:start position:0% +Orval order in which you removal + + + align:start position:0% +Orval order in which you removal +electrons form orbitals and the + + align:start position:0% +electrons form orbitals and the + + + align:start position:0% +electrons form orbitals and the +shielding arguments are capable of + + align:start position:0% +shielding arguments are capable of + + + align:start position:0% +shielding arguments are capable of +explaining that okay so this is the end + + align:start position:0% +explaining that okay so this is the end + + + align:start position:0% +explaining that okay so this is the end +of atoms and I've asked you to two to + + align:start position:0% +of atoms and I've asked you to two to + + + align:start position:0% +of atoms and I've asked you to two to +observe some complicated algebra which + + align:start position:0% +observe some complicated algebra which + + + align:start position:0% +observe some complicated algebra which +you're never going to do or at least + + align:start position:0% +you're never going to do or at least + + + align:start position:0% +you're never going to do or at least +never going to do much of everything you + + align:start position:0% +never going to do much of everything you + + + align:start position:0% +never going to do much of everything you +need to know about atoms you can tell a + + align:start position:0% +need to know about atoms you can tell a + + + align:start position:0% +need to know about atoms you can tell a +computer and it can do it now molecules + + align:start position:0% +computer and it can do it now molecules + + + align:start position:0% +computer and it can do it now molecules +are much more complicated and that's + + align:start position:0% +are much more complicated and that's + + + align:start position:0% +are much more complicated and that's +we're going to start on next time we're + + align:start position:0% +we're going to start on next time we're + + + align:start position:0% +we're going to start on next time we're +going to start with molecular orbital + + align:start position:0% +going to start with molecular orbital + + + align:start position:0% +going to start with molecular orbital +theory and I'm not going to be cos n + + align:start position:0% +theory and I'm not going to be cos n + + + align:start position:0% +theory and I'm not going to be cos n +ting the normal textbook approach I'm + + align:start position:0% +ting the normal textbook approach I'm + + + align:start position:0% +ting the normal textbook approach I'm +going to present an interpretive + + align:start position:0% +going to present an interpretive + + + align:start position:0% +going to present an interpretive +approach where you understand why things + + align:start position:0% +approach where you understand why things + + + align:start position:0% +approach where you understand why things +happen as opposed to memorize just + + align:start position:0% +happen as opposed to memorize just + + + align:start position:0% +happen as opposed to memorize just +symmetries and filling orders and so on + + align:start position:0% +symmetries and filling orders and so on + + + align:start position:0% +symmetries and filling orders and so on +okay I'll see you on Wednesday \ No newline at end of file diff --git a/K2cYzRGjWrE.txt b/K2cYzRGjWrE.txt new file mode 100644 index 0000000000000000000000000000000000000000..cff9497ccb155a0f8384f3377a0d29182eb4c1e3 --- /dev/null +++ b/K2cYzRGjWrE.txt @@ -0,0 +1,355 @@ +align:start position:0% + +Open education here means open resources + + align:start position:0% +Open education here means open resources + + + align:start position:0% +Open education here means open resources +in and outside of the classroom for our + + align:start position:0% +in and outside of the classroom for our + + + align:start position:0% +in and outside of the classroom for our +students. + + align:start position:0% +students. + + + align:start position:0% +students. +We're inventing a more open future for + + align:start position:0% +We're inventing a more open future for + + + align:start position:0% +We're inventing a more open future for +all curious minds by sharing a treasure + + align:start position:0% +all curious minds by sharing a treasure + + + align:start position:0% +all curious minds by sharing a treasure +of knowledge for you to discover + + align:start position:0% +of knowledge for you to discover + + + align:start position:0% +of knowledge for you to discover +anywhere, anytime. + + align:start position:0% +anywhere, anytime. + + + align:start position:0% +anywhere, anytime. +We're rethinking open by recognizing + + align:start position:0% +We're rethinking open by recognizing + + + align:start position:0% +We're rethinking open by recognizing +voices and expertise from people of + + align:start position:0% +voices and expertise from people of + + + align:start position:0% +voices and expertise from people of +diverse backgrounds are absolutely + + align:start position:0% +diverse backgrounds are absolutely + + + align:start position:0% +diverse backgrounds are absolutely +necessary for expanding and growing open + + align:start position:0% +necessary for expanding and growing open + + + align:start position:0% +necessary for expanding and growing open +educational resources. + + align:start position:0% +educational resources. + + + align:start position:0% +educational resources. +>> 20% of our faculty have adapted, adopted + + align:start position:0% +>> 20% of our faculty have adapted, adopted + + + align:start position:0% +>> 20% of our faculty have adapted, adopted +and/or created OEER. We are inventing a + + align:start position:0% +and/or created OEER. We are inventing a + + + align:start position:0% +and/or created OEER. We are inventing a +more open future for all consumers and + + align:start position:0% +more open future for all consumers and + + + align:start position:0% +more open future for all consumers and +producers of knowledge by leading in the + + align:start position:0% +producers of knowledge by leading in the + + + align:start position:0% +producers of knowledge by leading in the +development of sustainable open + + align:start position:0% +development of sustainable open + + + align:start position:0% +development of sustainable open +publishing models and open-source + + align:start position:0% +publishing models and open-source + + + align:start position:0% +publishing models and open-source +publishing technologies. We are + + align:start position:0% +publishing technologies. We are + + + align:start position:0% +publishing technologies. We are +relentless in our pursuit of a more open + + align:start position:0% +relentless in our pursuit of a more open + + + align:start position:0% +relentless in our pursuit of a more open +and equitable scholarly landscape. + + align:start position:0% +and equitable scholarly landscape. + + + align:start position:0% +and equitable scholarly landscape. +>> Open is democratizing learning and + + align:start position:0% +>> Open is democratizing learning and + + + align:start position:0% +>> Open is democratizing learning and +knowledge to the world. + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +here. Open is in our DNA. + + align:start position:0% +here. Open is in our DNA. + + + align:start position:0% +here. Open is in our DNA. +>> It captures Arab commitment to sharing + + align:start position:0% +>> It captures Arab commitment to sharing + + + align:start position:0% +>> It captures Arab commitment to sharing +our best educational contributions in a + + align:start position:0% +our best educational contributions in a + + + align:start position:0% +our best educational contributions in a +way that everyone can build on them and + + align:start position:0% +way that everyone can build on them and + + + align:start position:0% +way that everyone can build on them and +make them even better. + + align:start position:0% +make them even better. + + + align:start position:0% +make them even better. +>> Here, openness is a core value. We share + + align:start position:0% +>> Here, openness is a core value. We share + + + align:start position:0% +>> Here, openness is a core value. We share +information, innovations and ideas with + + align:start position:0% +information, innovations and ideas with + + + align:start position:0% +information, innovations and ideas with +enthusiasm. We champion open courseware, + + align:start position:0% +enthusiasm. We champion open courseware, + + + align:start position:0% +enthusiasm. We champion open courseware, +open access, and open science. All + + align:start position:0% +open access, and open science. All + + + align:start position:0% +open access, and open science. All +crucial to our mission. Our doors are + + align:start position:0% +crucial to our mission. Our doors are + + + align:start position:0% +crucial to our mission. Our doors are +open, too. So, come join us. + + align:start position:0% +open, too. So, come join us. + + + align:start position:0% +open, too. So, come join us. +>> Come join us. + + align:start position:0% +>> Come join us. + + + align:start position:0% +>> Come join us. +>> Come join us. + + align:start position:0% +>> Come join us. + + + align:start position:0% +>> Come join us. +>> Come invent with us. + + align:start position:0% +>> Come invent with us. + + + align:start position:0% +>> Come invent with us. +>> Come invent with us. + + align:start position:0% +>> Come invent with us. + + + align:start position:0% +>> Come invent with us. +>> We can't wait to welcome you. + + align:start position:0% +>> We can't wait to welcome you. + + + align:start position:0% +>> We can't wait to welcome you. +>> I think you would enjoy seeing Cambridge + + align:start position:0% +>> I think you would enjoy seeing Cambridge + + + align:start position:0% +>> I think you would enjoy seeing Cambridge +and I certainly look forward to meeting + + align:start position:0% +and I certainly look forward to meeting + + + align:start position:0% +and I certainly look forward to meeting +you. So, let's do it. + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +[Music] \ No newline at end of file diff --git a/K7QVIqV2QMk.txt b/K7QVIqV2QMk.txt new file mode 100644 index 0000000000000000000000000000000000000000..2e0afdea258b2c3eb9c01f8baac5116c7a635524 --- /dev/null +++ b/K7QVIqV2QMk.txt @@ -0,0 +1,23931 @@ +align:start position:0% + +all right + + align:start position:0% +all right + + + align:start position:0% +all right +welcome everyone to lecture 13 of 1413. + + align:start position:0% +welcome everyone to lecture 13 of 1413. + + + align:start position:0% +welcome everyone to lecture 13 of 1413. +this is my last lecture on social + + align:start position:0% +this is my last lecture on social + + + align:start position:0% +this is my last lecture on social +preferences i hope all of you are + + align:start position:0% +preferences i hope all of you are + + + align:start position:0% +preferences i hope all of you are +doing fine remotely hang in there i know + + align:start position:0% +doing fine remotely hang in there i know + + + align:start position:0% +doing fine remotely hang in there i know +this is a very difficult time + + align:start position:0% +this is a very difficult time + + + align:start position:0% +this is a very difficult time +this lecture is a bit of a more + + align:start position:0% +this lecture is a bit of a more + + + align:start position:0% +this lecture is a bit of a more +uplifting lecture than the previous ones + + align:start position:0% +uplifting lecture than the previous ones + + + align:start position:0% +uplifting lecture than the previous ones +well the previous ones have looked at + + align:start position:0% +well the previous ones have looked at + + + align:start position:0% +well the previous ones have looked at +social preferences how we can measure + + align:start position:0% +social preferences how we can measure + + + align:start position:0% +social preferences how we can measure +social preferences + + align:start position:0% +social preferences + + + align:start position:0% +social preferences +and how can we perhaps isolate pure + + align:start position:0% +and how can we perhaps isolate pure + + + align:start position:0% +and how can we perhaps isolate pure +altruism + + align:start position:0% +altruism + + + align:start position:0% +altruism +do people really want others to be + + align:start position:0% +do people really want others to be + + + align:start position:0% +do people really want others to be +better for their own sake + + align:start position:0% +better for their own sake + + + align:start position:0% +better for their own sake +even if nobody knows about it either + + align:start position:0% +even if nobody knows about it either + + + align:start position:0% +even if nobody knows about it either +others + + align:start position:0% +others + + + align:start position:0% +others +or or whether there's no feedback um + + align:start position:0% +or or whether there's no feedback um + + + align:start position:0% +or or whether there's no feedback um +we sort of found out that like it seems + + align:start position:0% +we sort of found out that like it seems + + + align:start position:0% +we sort of found out that like it seems +like what looks a lot like + + align:start position:0% +like what looks a lot like + + + align:start position:0% +like what looks a lot like +altruism people are nice to each other + + align:start position:0% +altruism people are nice to each other + + + align:start position:0% +altruism people are nice to each other +it's not pure altruism in the sense that + + align:start position:0% +it's not pure altruism in the sense that + + + align:start position:0% +it's not pure altruism in the sense that +like + + align:start position:0% +like + + + align:start position:0% +like +they really want others to do well + + align:start position:0% +they really want others to do well + + + align:start position:0% +they really want others to do well +instead + + align:start position:0% +instead + + + align:start position:0% +instead +they want to either look good in front + + align:start position:0% +they want to either look good in front + + + align:start position:0% +they want to either look good in front +of others or like you know they're + + align:start position:0% +of others or like you know they're + + + align:start position:0% +of others or like you know they're +worried about reciprocity or sort of any + + align:start position:0% +worried about reciprocity or sort of any + + + align:start position:0% +worried about reciprocity or sort of any +other negative feedback from others + + align:start position:0% +other negative feedback from others + + + align:start position:0% +other negative feedback from others +or it might be they might want uh to + + align:start position:0% +or it might be they might want uh to + + + align:start position:0% +or it might be they might want uh to +protect their self-image they want to + + align:start position:0% +protect their self-image they want to + + + align:start position:0% +protect their self-image they want to +look good + + align:start position:0% +look good + + + align:start position:0% +look good +in front of themselves and they try to + + align:start position:0% +in front of themselves and they try to + + + align:start position:0% +in front of themselves and they try to +figure out ways to + + align:start position:0% +figure out ways to + + + align:start position:0% +figure out ways to +um deceive themselves that they're nice + + align:start position:0% +um deceive themselves that they're nice + + + align:start position:0% +um deceive themselves that they're nice +and if given the opportunity to not be + + align:start position:0% +and if given the opportunity to not be + + + align:start position:0% +and if given the opportunity to not be +nice + + align:start position:0% +nice + + + align:start position:0% +nice +people actually seem to be not as nice + + align:start position:0% +people actually seem to be not as nice + + + align:start position:0% +people actually seem to be not as nice +as one might think from pure dictator + + align:start position:0% +as one might think from pure dictator + + + align:start position:0% +as one might think from pure dictator +games or + + align:start position:0% +games or + + + align:start position:0% +games or +ultimatum games that we observe this + + align:start position:0% +ultimatum games that we observe this + + + align:start position:0% +ultimatum games that we observe this +lecture is a bit more + + align:start position:0% +lecture is a bit more + + + align:start position:0% +lecture is a bit more +uplifting in the sense that it talks + + align:start position:0% +uplifting in the sense that it talks + + + align:start position:0% +uplifting in the sense that it talks +about + + align:start position:0% +about + + + align:start position:0% +about +field evidence on social preferences and + + align:start position:0% +field evidence on social preferences and + + + align:start position:0% +field evidence on social preferences and +in particular + + align:start position:0% +in particular + + + align:start position:0% +in particular +we're going to ask the question about + + align:start position:0% +we're going to ask the question about + + + align:start position:0% +we're going to ask the question about +how can or can policies increase + + align:start position:0% +how can or can policies increase + + + align:start position:0% +how can or can policies increase +pro-sociality in certain ways we're + + align:start position:0% +pro-sociality in certain ways we're + + + align:start position:0% +pro-sociality in certain ways we're +going to talk about three broad + + align:start position:0% +going to talk about three broad + + + align:start position:0% +going to talk about three broad +sets of studies first we're going to + + align:start position:0% +sets of studies first we're going to + + + align:start position:0% +sets of studies first we're going to +talk about social preferences at the + + align:start position:0% +talk about social preferences at the + + + align:start position:0% +talk about social preferences at the +workplace + + align:start position:0% +workplace + + + align:start position:0% +workplace +i'm going to talk about the impact of + + align:start position:0% +i'm going to talk about the impact of + + + align:start position:0% +i'm going to talk about the impact of +relative pay + + align:start position:0% +relative pay + + + align:start position:0% +relative pay +on productivity we talked about this + + align:start position:0% +on productivity we talked about this + + + align:start position:0% +on productivity we talked about this +last time at the end of the lecture a + + align:start position:0% +last time at the end of the lecture a + + + align:start position:0% +last time at the end of the lecture a +little bit + + align:start position:0% +little bit + + + align:start position:0% +little bit +but i'm going to just restart from + + align:start position:0% +but i'm going to just restart from + + + align:start position:0% +but i'm going to just restart from +scratch to sort of explain that a little + + align:start position:0% +scratch to sort of explain that a little + + + align:start position:0% +scratch to sort of explain that a little +bit better + + align:start position:0% +bit better + + + align:start position:0% +bit better +then we're going to talk about the + + align:start position:0% +then we're going to talk about the + + + align:start position:0% +then we're going to talk about the +morale effects of pay inequality + + align:start position:0% +morale effects of pay inequality + + + align:start position:0% +morale effects of pay inequality +what happens to worker inequality when + + align:start position:0% +what happens to worker inequality when + + + align:start position:0% +what happens to worker inequality when +people are paid + + align:start position:0% +people are paid + + + align:start position:0% +people are paid +unequally and is that a good idea + + align:start position:0% +unequally and is that a good idea + + + align:start position:0% +unequally and is that a good idea +there's also a very nice paper in ethnic + + align:start position:0% +there's also a very nice paper in ethnic + + + align:start position:0% +there's also a very nice paper in ethnic +divisions and production in firms + + align:start position:0% +divisions and production in firms + + + align:start position:0% +divisions and production in firms +we're going to talk about this a little + + align:start position:0% +we're going to talk about this a little + + + align:start position:0% +we're going to talk about this a little +bit in recitation + + align:start position:0% +bit in recitation + + + align:start position:0% +bit in recitation +number two we're going to talk about um + + align:start position:0% +number two we're going to talk about um + + + align:start position:0% +number two we're going to talk about um +uh whether policies can + + align:start position:0% +uh whether policies can + + + align:start position:0% +uh whether policies can +induce uh prosecutionality in particular + + align:start position:0% +induce uh prosecutionality in particular + + + align:start position:0% +induce uh prosecutionality in particular +in a focus on mixing this is sort of the + + align:start position:0% +in a focus on mixing this is sort of the + + + align:start position:0% +in a focus on mixing this is sort of the +called the contact hypothesis when you + + align:start position:0% +called the contact hypothesis when you + + + align:start position:0% +called the contact hypothesis when you +mix people from different backgrounds + + align:start position:0% +mix people from different backgrounds + + + align:start position:0% +mix people from different backgrounds +do they become nicer to each other in + + align:start position:0% +do they become nicer to each other in + + + align:start position:0% +do they become nicer to each other in +various ways + + align:start position:0% +various ways + + + align:start position:0% +various ways +um you know discuss a very nice paper by + + align:start position:0% +um you know discuss a very nice paper by + + + align:start position:0% +um you know discuss a very nice paper by +gautam rao on mixing rich and poor + + align:start position:0% +gautam rao on mixing rich and poor + + + align:start position:0% +gautam rao on mixing rich and poor +children in school they're going to talk + + align:start position:0% +children in school they're going to talk + + + align:start position:0% +children in school they're going to talk +very briefly about mixing cricket + + align:start position:0% +very briefly about mixing cricket + + + align:start position:0% +very briefly about mixing cricket +players + + align:start position:0% +players + + + align:start position:0% +players +in india to reduce tensions across + + align:start position:0% +in india to reduce tensions across + + + align:start position:0% +in india to reduce tensions across +castes or make people from different + + align:start position:0% +castes or make people from different + + + align:start position:0% +castes or make people from different +casts + + align:start position:0% +casts + + + align:start position:0% +casts +perhaps more pro-social to each other + + align:start position:0% +perhaps more pro-social to each other + + + align:start position:0% +perhaps more pro-social to each other +i'm going to also briefly mention a + + align:start position:0% +i'm going to also briefly mention a + + + align:start position:0% +i'm going to also briefly mention a +study on mixing roommates in college + + align:start position:0% +study on mixing roommates in college + + + align:start position:0% +study on mixing roommates in college +by coronado finally we're going to talk + + align:start position:0% +by coronado finally we're going to talk + + + align:start position:0% +by coronado finally we're going to talk +about + + align:start position:0% +about + + + align:start position:0% +about +whether people perhaps underestimate the + + align:start position:0% +whether people perhaps underestimate the + + + align:start position:0% +whether people perhaps underestimate the +benefits of prosociality + + align:start position:0% +benefits of prosociality + + + align:start position:0% +benefits of prosociality +in particular i'm going to show you a + + align:start position:0% +in particular i'm going to show you a + + + align:start position:0% +in particular i'm going to show you a +study on people undervaluing gratitude + + align:start position:0% +study on people undervaluing gratitude + + + align:start position:0% +study on people undervaluing gratitude +so when people write letters of + + align:start position:0% +so when people write letters of + + + align:start position:0% +so when people write letters of +gratitude do others + + align:start position:0% +gratitude do others + + + align:start position:0% +gratitude do others +or do they understand how others might + + align:start position:0% +or do they understand how others might + + + align:start position:0% +or do they understand how others might +react and + + align:start position:0% +react and + + + align:start position:0% +react and +perhaps can be is there perhaps some + + align:start position:0% +perhaps can be is there perhaps some + + + align:start position:0% +perhaps can be is there perhaps some +evidence that people + + align:start position:0% +evidence that people + + + align:start position:0% +evidence that people +are not pro-social enough because they + + align:start position:0% +are not pro-social enough because they + + + align:start position:0% +are not pro-social enough because they +misunderstand + + align:start position:0% +misunderstand + + + align:start position:0% +misunderstand +the effects that that might have on + + align:start position:0% +the effects that that might have on + + + align:start position:0% +the effects that that might have on +others + + align:start position:0% +others + + + align:start position:0% +others +okay so let me + + align:start position:0% + + + + align:start position:0% + +let me start with social preferences at + + align:start position:0% +let me start with social preferences at + + + align:start position:0% +let me start with social preferences at +the workplace so + + align:start position:0% +the workplace so + + + align:start position:0% +the workplace so +um bandaranadel is a very nice study + + align:start position:0% +um bandaranadel is a very nice study + + + align:start position:0% +um bandaranadel is a very nice study +that looks at the impact of relative pay + + align:start position:0% +that looks at the impact of relative pay + + + align:start position:0% +that looks at the impact of relative pay +on productivity + + align:start position:0% +on productivity + + + align:start position:0% +on productivity +this is field evidence from a fruit farm + + align:start position:0% +this is field evidence from a fruit farm + + + align:start position:0% +this is field evidence from a fruit farm +in the uk it's literally field evidence + + align:start position:0% +in the uk it's literally field evidence + + + align:start position:0% +in the uk it's literally field evidence +because it's from fruit picking farms + + align:start position:0% +because it's from fruit picking farms + + + align:start position:0% +because it's from fruit picking farms +from food fields + + align:start position:0% +from food fields + + + align:start position:0% +from food fields +the study looks at two types of payment + + align:start position:0% +the study looks at two types of payment + + + align:start position:0% +the study looks at two types of payment +schemes these are + + align:start position:0% +schemes these are + + + align:start position:0% +schemes these are +piece rates workers are paid per unit of + + align:start position:0% +piece rates workers are paid per unit of + + + align:start position:0% +piece rates workers are paid per unit of +output + + align:start position:0% +output + + + align:start position:0% +output +and the second scheme is relative pay + + align:start position:0% +and the second scheme is relative pay + + + align:start position:0% +and the second scheme is relative pay +workers are paid relative to others + + align:start position:0% +workers are paid relative to others + + + align:start position:0% +workers are paid relative to others +we might sort of think that relative pay + + align:start position:0% +we might sort of think that relative pay + + + align:start position:0% +we might sort of think that relative pay +is a good way to incentivize workers + + align:start position:0% +is a good way to incentivize workers + + + align:start position:0% +is a good way to incentivize workers +because you know you want to do better + + align:start position:0% +because you know you want to do better + + + align:start position:0% +because you know you want to do better +than + + align:start position:0% +than + + + align:start position:0% +than +uh your neighbor and there's sort of a + + align:start position:0% +uh your neighbor and there's sort of a + + + align:start position:0% +uh your neighbor and there's sort of a +competition + + align:start position:0% +competition + + + align:start position:0% +competition +of who does best and in principle it + + align:start position:0% +of who does best and in principle it + + + align:start position:0% +of who does best and in principle it +could be that like that really if you + + align:start position:0% +could be that like that really if you + + + align:start position:0% +could be that like that really if you +only care about yourself that really + + align:start position:0% +only care about yourself that really + + + align:start position:0% +only care about yourself that really +gets people to work very hard + + align:start position:0% +gets people to work very hard + + + align:start position:0% +gets people to work very hard +now what bandiera now look at is like + + align:start position:0% +now what bandiera now look at is like + + + align:start position:0% +now what bandiera now look at is like +does or how does the + + align:start position:0% +does or how does the + + + align:start position:0% +does or how does the +introduction of relative pay affect + + align:start position:0% +introduction of relative pay affect + + + align:start position:0% +introduction of relative pay affect +workers + + align:start position:0% +workers + + + align:start position:0% +workers +effort and output now one thing they + + align:start position:0% +effort and output now one thing they + + + align:start position:0% +effort and output now one thing they +notice is that + + align:start position:0% +notice is that + + + align:start position:0% +notice is that +while um relative incentives might be + + align:start position:0% +while um relative incentives might be + + + align:start position:0% +while um relative incentives might be +good because you might sort of + + align:start position:0% +good because you might sort of + + + align:start position:0% +good because you might sort of +induce people to want to be better than + + align:start position:0% +induce people to want to be better than + + + align:start position:0% +induce people to want to be better than +their um + + align:start position:0% +their um + + + align:start position:0% +their um +their neighbors or their co-workers + + align:start position:0% +their neighbors or their co-workers + + + align:start position:0% +their neighbors or their co-workers +there's also a negative + + align:start position:0% +there's also a negative + + + align:start position:0% +there's also a negative +externality of relative pay that is the + + align:start position:0% +externality of relative pay that is the + + + align:start position:0% +externality of relative pay that is the +idea that increasing + + align:start position:0% +idea that increasing + + + align:start position:0% +idea that increasing +your own pay comes at the cost of others + + align:start position:0% +your own pay comes at the cost of others + + + align:start position:0% +your own pay comes at the cost of others +pay + + align:start position:0% +pay + + + align:start position:0% +pay +that is to say if there's relative pay + + align:start position:0% +that is to say if there's relative pay + + + align:start position:0% +that is to say if there's relative pay +and i work really hard + + align:start position:0% +and i work really hard + + + align:start position:0% +and i work really hard +i'm paid how i do relative to my friends + + align:start position:0% +i'm paid how i do relative to my friends + + + align:start position:0% +i'm paid how i do relative to my friends +or others that i'm working with + + align:start position:0% +or others that i'm working with + + + align:start position:0% +or others that i'm working with +well if i'm working really hard and do + + align:start position:0% +well if i'm working really hard and do + + + align:start position:0% +well if i'm working really hard and do +better than my friends i'm going to be + + align:start position:0% +better than my friends i'm going to be + + + align:start position:0% +better than my friends i'm going to be +paid more + + align:start position:0% +paid more + + + align:start position:0% +paid more +but at the same time my friends for any + + align:start position:0% +but at the same time my friends for any + + + align:start position:0% +but at the same time my friends for any +effort that i put in + + align:start position:0% +effort that i put in + + + align:start position:0% +effort that i put in +my friends are going to be paid less and + + align:start position:0% +my friends are going to be paid less and + + + align:start position:0% +my friends are going to be paid less and +so + + align:start position:0% +so + + + align:start position:0% +so +workers sort of anticipating these + + align:start position:0% +workers sort of anticipating these + + + align:start position:0% +workers sort of anticipating these +impacts on on others + + align:start position:0% +impacts on on others + + + align:start position:0% +impacts on on others +might reduce their effort if they care + + align:start position:0% +might reduce their effort if they care + + + align:start position:0% +might reduce their effort if they care +about others right if i'm really worried + + align:start position:0% +about others right if i'm really worried + + + align:start position:0% +about others right if i'm really worried +about like if there's relative pay and i + + align:start position:0% +about like if there's relative pay and i + + + align:start position:0% +about like if there's relative pay and i +work really hard my friends are going to + + align:start position:0% +work really hard my friends are going to + + + align:start position:0% +work really hard my friends are going to +look bad + + align:start position:0% +look bad + + + align:start position:0% +look bad +they're going to be relatively uh + + align:start position:0% +they're going to be relatively uh + + + align:start position:0% +they're going to be relatively uh +unproductive + + align:start position:0% +unproductive + + + align:start position:0% +unproductive +and i worry that they might not be paid + + align:start position:0% +and i worry that they might not be paid + + + align:start position:0% +and i worry that they might not be paid +enough + + align:start position:0% +enough + + + align:start position:0% +enough +then um i might reduce my effort and + + align:start position:0% +then um i might reduce my effort and + + + align:start position:0% +then um i might reduce my effort and +sort of everybody might do that and then + + align:start position:0% +sort of everybody might do that and then + + + align:start position:0% +sort of everybody might do that and then +the introduction of relative pay or the + + align:start position:0% +the introduction of relative pay or the + + + align:start position:0% +the introduction of relative pay or the +relative pay schemes might actually not + + align:start position:0% +relative pay schemes might actually not + + + align:start position:0% +relative pay schemes might actually not +be particularly + + align:start position:0% +be particularly + + + align:start position:0% +be particularly +uh effective or effective way of + + align:start position:0% +uh effective or effective way of + + + align:start position:0% +uh effective or effective way of +incentivizing + + align:start position:0% +incentivizing + + + align:start position:0% +incentivizing +and motivating workers so there's sort + + align:start position:0% +and motivating workers so there's sort + + + align:start position:0% +and motivating workers so there's sort +of this tension that relative pain + + align:start position:0% +of this tension that relative pain + + + align:start position:0% +of this tension that relative pain +principle + + align:start position:0% +principle + + + align:start position:0% +principle +could work quite well but if people + + align:start position:0% +could work quite well but if people + + + align:start position:0% +could work quite well but if people +really care a lot about others + + align:start position:0% +really care a lot about others + + + align:start position:0% +really care a lot about others +then it might not work at all it might + + align:start position:0% +then it might not work at all it might + + + align:start position:0% +then it might not work at all it might +actually backfire in some ways + + align:start position:0% +actually backfire in some ways + + + align:start position:0% +actually backfire in some ways +notice that it could be either that + + align:start position:0% +notice that it could be either that + + + align:start position:0% +notice that it could be either that +people care about others + + align:start position:0% +people care about others + + + align:start position:0% +people care about others +for their own sake in the sense that + + align:start position:0% +for their own sake in the sense that + + + align:start position:0% +for their own sake in the sense that +like you might care about them + + align:start position:0% +like you might care about them + + + align:start position:0% +like you might care about them +because you want them to have high + + align:start position:0% +because you want them to have high + + + align:start position:0% +because you want them to have high +earnings or you might care about + + align:start position:0% +earnings or you might care about + + + align:start position:0% +earnings or you might care about +others earnings not because you actually + + align:start position:0% +others earnings not because you actually + + + align:start position:0% +others earnings not because you actually +care about the outcomes per se + + align:start position:0% +care about the outcomes per se + + + align:start position:0% +care about the outcomes per se +but rather because you're worried about + + align:start position:0% +but rather because you're worried about + + + align:start position:0% +but rather because you're worried about +negative repercussions right if these + + align:start position:0% +negative repercussions right if these + + + align:start position:0% +negative repercussions right if these +are your friends and you worked really + + align:start position:0% +are your friends and you worked really + + + align:start position:0% +are your friends and you worked really +hard + + align:start position:0% +hard + + + align:start position:0% +hard +well at night your friends might really + + align:start position:0% +well at night your friends might really + + + align:start position:0% +well at night your friends might really +not be happy and there might be sort of + + align:start position:0% +not be happy and there might be sort of + + + align:start position:0% +not be happy and there might be sort of +retribution against you + + align:start position:0% +retribution against you + + + align:start position:0% +retribution against you +socially or in some other ways if you + + align:start position:0% +socially or in some other ways if you + + + align:start position:0% +socially or in some other ways if you +work too hard if you cause them + + align:start position:0% +work too hard if you cause them + + + align:start position:0% +work too hard if you cause them +their earnings to go down okay + + align:start position:0% +their earnings to go down okay + + + align:start position:0% +their earnings to go down okay +so now what does this paper do it looks + + align:start position:0% +so now what does this paper do it looks + + + align:start position:0% +so now what does this paper do it looks +at how does switching to + + align:start position:0% +at how does switching to + + + align:start position:0% +at how does switching to +to piece rates affect the people's + + align:start position:0% +to piece rates affect the people's + + + align:start position:0% +to piece rates affect the people's +productivity um + + align:start position:0% +productivity um + + + align:start position:0% +productivity um +so the study has personnel data from a + + align:start position:0% +so the study has personnel data from a + + + align:start position:0% +so the study has personnel data from a +food farm in the uk + + align:start position:0% +food farm in the uk + + + align:start position:0% +food farm in the uk +they measure productivity as a function + + align:start position:0% +they measure productivity as a function + + + align:start position:0% +they measure productivity as a function +of their compensation scheme + + align:start position:0% +of their compensation scheme + + + align:start position:0% +of their compensation scheme +this is a quasi-field experiment the + + align:start position:0% +this is a quasi-field experiment the + + + align:start position:0% +this is a quasi-field experiment the +timeline is as follows + + align:start position:0% +timeline is as follows + + + align:start position:0% +timeline is as follows +for the first eight weeks of the 2002 + + align:start position:0% +for the first eight weeks of the 2002 + + + align:start position:0% +for the first eight weeks of the 2002 +picking season + + align:start position:0% +picking season + + + align:start position:0% +picking season +fruit pickers were compensated relative + + align:start position:0% +fruit pickers were compensated relative + + + align:start position:0% +fruit pickers were compensated relative +on a relative performance scheme so um + + align:start position:0% +on a relative performance scheme so um + + + align:start position:0% +on a relative performance scheme so um +uh + + align:start position:0% +uh + + + align:start position:0% +uh +the per fruit piece the per piece rate + + align:start position:0% +the per fruit piece the per piece rate + + + align:start position:0% +the per fruit piece the per piece rate +is decreasing in average productivity + + align:start position:0% +is decreasing in average productivity + + + align:start position:0% +is decreasing in average productivity +right so like if everybody works really + + align:start position:0% +right so like if everybody works really + + + align:start position:0% +right so like if everybody works really +hard and i don't if i'm relatively bad + + align:start position:0% +hard and i don't if i'm relatively bad + + + align:start position:0% +hard and i don't if i'm relatively bad +compared to other i get less + + align:start position:0% +compared to other i get less + + + align:start position:0% +compared to other i get less +than others the incentive to keep this + + align:start position:0% +than others the incentive to keep this + + + align:start position:0% +than others the incentive to keep this +is sort of an incentive to keep as i + + align:start position:0% +is sort of an incentive to keep as i + + + align:start position:0% +is sort of an incentive to keep as i +discussed + + align:start position:0% +discussed + + + align:start position:0% +discussed +to keep the productivity low if you care + + align:start position:0% +to keep the productivity low if you care + + + align:start position:0% +to keep the productivity low if you care +about others + + align:start position:0% +about others + + + align:start position:0% +about others +and then in the next eight weeks + + align:start position:0% +and then in the next eight weeks + + + align:start position:0% +and then in the next eight weeks +compensation was switched to a flat + + align:start position:0% +compensation was switched to a flat + + + align:start position:0% +compensation was switched to a flat +piece rate per fruit + + align:start position:0% +piece rate per fruit + + + align:start position:0% +piece rate per fruit +so that's essentially just like you're + + align:start position:0% +so that's essentially just like you're + + + align:start position:0% +so that's essentially just like you're +paid by however you + + align:start position:0% +paid by however you + + + align:start position:0% +paid by however you +how much you produce how many kilograms + + align:start position:0% +how much you produce how many kilograms + + + align:start position:0% +how much you produce how many kilograms +of fruit you + + align:start position:0% +of fruit you + + + align:start position:0% +of fruit you +collect and the payment is + + align:start position:0% +collect and the payment is + + + align:start position:0% +collect and the payment is +entirely disjoint or independent of what + + align:start position:0% +entirely disjoint or independent of what + + + align:start position:0% +entirely disjoint or independent of what +other peoples do that's like a classic + + align:start position:0% +other peoples do that's like a classic + + + align:start position:0% +other peoples do that's like a classic +piece rate + + align:start position:0% +piece rate + + + align:start position:0% +piece rate +payment so the externalities are + + align:start position:0% +payment so the externalities are + + + align:start position:0% +payment so the externalities are +entirely shut down + + align:start position:0% +entirely shut down + + + align:start position:0% +entirely shut down +if i work really hard i'm going to be + + align:start position:0% +if i work really hard i'm going to be + + + align:start position:0% +if i work really hard i'm going to be +paid + + align:start position:0% +paid + + + align:start position:0% +paid +there's no effect whatsoever on my + + align:start position:0% +there's no effect whatsoever on my + + + align:start position:0% +there's no effect whatsoever on my +fellow workers + + align:start position:0% +fellow workers + + + align:start position:0% +fellow workers +the switch was announced on the day the + + align:start position:0% +the switch was announced on the day the + + + align:start position:0% +the switch was announced on the day the +change took place so it came as a + + align:start position:0% +change took place so it came as a + + + align:start position:0% +change took place so it came as a +surprise to workers we so we should not + + align:start position:0% +surprise to workers we so we should not + + + align:start position:0% +surprise to workers we so we should not +be worried about sort of + + align:start position:0% +be worried about sort of + + + align:start position:0% +be worried about sort of +pre-trends or productivity going up over + + align:start position:0% +pre-trends or productivity going up over + + + align:start position:0% +pre-trends or productivity going up over +time + + align:start position:0% +time + + + align:start position:0% +time +anyway now what the people find is a + + align:start position:0% +anyway now what the people find is a + + + align:start position:0% +anyway now what the people find is a +dramatic increase in productivity with + + align:start position:0% +dramatic increase in productivity with + + + align:start position:0% +dramatic increase in productivity with +the introduction of piece rates + + align:start position:0% +the introduction of piece rates + + + align:start position:0% +the introduction of piece rates +that is to say um what you see here in + + align:start position:0% +that is to say um what you see here in + + + align:start position:0% +that is to say um what you see here in +the figure is + + align:start position:0% +the figure is + + + align:start position:0% +the figure is +the average worker productivity for two + + align:start position:0% +the average worker productivity for two + + + align:start position:0% +the average worker productivity for two +of the fields so this essentially like + + align:start position:0% +of the fields so this essentially like + + + align:start position:0% +of the fields so this essentially like +broad big fields where people work on + + align:start position:0% +broad big fields where people work on + + + align:start position:0% +broad big fields where people work on +i'm showing you sort of the data for two + + align:start position:0% +i'm showing you sort of the data for two + + + align:start position:0% +i'm showing you sort of the data for two +of those fields for which essentially on + + align:start position:0% +of those fields for which essentially on + + + align:start position:0% +of those fields for which essentially on +most days + + align:start position:0% +most days + + + align:start position:0% +most days +there was actually production workers + + align:start position:0% +there was actually production workers + + + align:start position:0% +there was actually production workers +were picking fruit + + align:start position:0% +were picking fruit + + + align:start position:0% +were picking fruit +what you see on the left side of the + + align:start position:0% +what you see on the left side of the + + + align:start position:0% +what you see on the left side of the +graph is um + + align:start position:0% +graph is um + + + align:start position:0% +graph is um +when uh people were working under under + + align:start position:0% +when uh people were working under under + + + align:start position:0% +when uh people were working under under +relative pay + + align:start position:0% +relative pay + + + align:start position:0% +relative pay +there you see essentially relative flat + + align:start position:0% +there you see essentially relative flat + + + align:start position:0% +there you see essentially relative flat +productivity + + align:start position:0% +productivity + + + align:start position:0% +productivity +people had about like five kilograms + + align:start position:0% +people had about like five kilograms + + + align:start position:0% +people had about like five kilograms +picked about five kilograms per hour + + align:start position:0% +picked about five kilograms per hour + + + align:start position:0% +picked about five kilograms per hour +that doesn't seem to be any trend + + align:start position:0% +that doesn't seem to be any trend + + + align:start position:0% +that doesn't seem to be any trend +upwards over time so before the new + + align:start position:0% +upwards over time so before the new + + + align:start position:0% +upwards over time so before the new +policy was introduced essentially + + align:start position:0% +policy was introduced essentially + + + align:start position:0% +policy was introduced essentially +workers were + + align:start position:0% +workers were + + + align:start position:0% +workers were +producing um or picking their food at a + + align:start position:0% +producing um or picking their food at a + + + align:start position:0% +producing um or picking their food at a +relatively constant rate over time about + + align:start position:0% +relatively constant rate over time about + + + align:start position:0% +relatively constant rate over time about +five kilograms + + align:start position:0% +five kilograms + + + align:start position:0% +five kilograms +per hour there was no trends as i said + + align:start position:0% +per hour there was no trends as i said + + + align:start position:0% +per hour there was no trends as i said +now then you see so the vertical line um + + align:start position:0% +now then you see so the vertical line um + + + align:start position:0% +now then you see so the vertical line um +in the middle + + align:start position:0% +in the middle + + + align:start position:0% +in the middle +this is when um piece rates were in fact + + align:start position:0% +this is when um piece rates were in fact + + + align:start position:0% +this is when um piece rates were in fact +um uh introduced so there was no + + align:start position:0% +um uh introduced so there was no + + + align:start position:0% +um uh introduced so there was no +relative pay anymore and now they were + + align:start position:0% +relative pay anymore and now they were + + + align:start position:0% +relative pay anymore and now they were +people were paid by piece rate + + align:start position:0% +people were paid by piece rate + + + align:start position:0% +people were paid by piece rate +and that increased productivity by over + + align:start position:0% +and that increased productivity by over + + + align:start position:0% +and that increased productivity by over +50 so workers became a lot more + + align:start position:0% +50 so workers became a lot more + + + align:start position:0% +50 so workers became a lot more +productive + + align:start position:0% +productive + + + align:start position:0% +productive +after that um that's true for both of + + align:start position:0% +after that um that's true for both of + + + align:start position:0% +after that um that's true for both of +those + + align:start position:0% +those + + + align:start position:0% +those +fields it is not the case that the + + align:start position:0% +fields it is not the case that the + + + align:start position:0% +fields it is not the case that the +average + + align:start position:0% +average + + + align:start position:0% +average +payment per unit of output per kilogram + + align:start position:0% +payment per unit of output per kilogram + + + align:start position:0% +payment per unit of output per kilogram +uh + + align:start position:0% +uh + + + align:start position:0% +uh +for people were paid were actually was + + align:start position:0% +for people were paid were actually was + + + align:start position:0% +for people were paid were actually was +going up so you might sort of say well + + align:start position:0% +going up so you might sort of say well + + + align:start position:0% +going up so you might sort of say well +you know if the piece rate was actually + + align:start position:0% +you know if the piece rate was actually + + + align:start position:0% +you know if the piece rate was actually +higher + + align:start position:0% +higher + + + align:start position:0% +higher +um under the piece rate payments + + align:start position:0% +um under the piece rate payments + + + align:start position:0% +um under the piece rate payments +on the right side of the screen well + + align:start position:0% +on the right side of the screen well + + + align:start position:0% +on the right side of the screen well +maybe then you know of the graph then + + align:start position:0% +maybe then you know of the graph then + + + align:start position:0% +maybe then you know of the graph then +maybe workers would just be more + + align:start position:0% +maybe workers would just be more + + + align:start position:0% +maybe workers would just be more +productive + + align:start position:0% +productive + + + align:start position:0% +productive +but in fact if you look at sort of the + + align:start position:0% +but in fact if you look at sort of the + + + align:start position:0% +but in fact if you look at sort of the +piece rate over time if anything the + + align:start position:0% +piece rate over time if anything the + + + align:start position:0% +piece rate over time if anything the +piece rates actually went down over time + + align:start position:0% +piece rates actually went down over time + + + align:start position:0% +piece rates actually went down over time +what the + + align:start position:0% +what the + + + align:start position:0% +what the +company was paying so that is to say + + align:start position:0% +company was paying so that is to say + + + align:start position:0% +company was paying so that is to say +the introduction of those piece rates + + align:start position:0% +the introduction of those piece rates + + + align:start position:0% +the introduction of those piece rates +the productivity effect is not explained + + align:start position:0% +the productivity effect is not explained + + + align:start position:0% +the productivity effect is not explained +by workers being paid more + + align:start position:0% +by workers being paid more + + + align:start position:0% +by workers being paid more +per unit of output instead it seems to + + align:start position:0% +per unit of output instead it seems to + + + align:start position:0% +per unit of output instead it seems to +be really coming from the different + + align:start position:0% +be really coming from the different + + + align:start position:0% +be really coming from the different +incentives + + align:start position:0% +incentives + + + align:start position:0% +incentives +people workers have when it comes to how + + align:start position:0% +people workers have when it comes to how + + + align:start position:0% +people workers have when it comes to how +their productivity + + align:start position:0% +their productivity + + + align:start position:0% +their productivity +affects their fellow workers on the + + align:start position:0% +affects their fellow workers on the + + + align:start position:0% +affects their fellow workers on the +field + + align:start position:0% +field + + + align:start position:0% +field +now you might have sort of like two + + align:start position:0% +now you might have sort of like two + + + align:start position:0% +now you might have sort of like two +potential explanation here for this um + + align:start position:0% +potential explanation here for this um + + + align:start position:0% +potential explanation here for this um +uh evidence one is social preferences so + + align:start position:0% +uh evidence one is social preferences so + + + align:start position:0% +uh evidence one is social preferences so +you might work + + align:start position:0% +you might work + + + align:start position:0% +you might work +less um to help others under relative um + + align:start position:0% +less um to help others under relative um + + + align:start position:0% +less um to help others under relative um +uh incentives right and you might um + + align:start position:0% +uh incentives right and you might um + + + align:start position:0% +uh incentives right and you might um +um even less when your friends benefits + + align:start position:0% +um even less when your friends benefits + + + align:start position:0% +um even less when your friends benefits +you if you have many + + align:start position:0% +you if you have many + + + align:start position:0% +you if you have many +uh friends on a certain field that work + + align:start position:0% +uh friends on a certain field that work + + + align:start position:0% +uh friends on a certain field that work +with you + + align:start position:0% +with you + + + align:start position:0% +with you +well then you might be particularly + + align:start position:0% +well then you might be particularly + + + align:start position:0% +well then you might be particularly +inclined to not work very hard + + align:start position:0% +inclined to not work very hard + + + align:start position:0% +inclined to not work very hard +because you will care a lot more um uh + + align:start position:0% +because you will care a lot more um uh + + + align:start position:0% +because you will care a lot more um uh +for them + + align:start position:0% +for them + + + align:start position:0% +for them +and this is sort of exactly what they + + align:start position:0% +and this is sort of exactly what they + + + align:start position:0% +and this is sort of exactly what they +find in this paper uh these effects are + + align:start position:0% +find in this paper uh these effects are + + + align:start position:0% +find in this paper uh these effects are +stronger when they're more + + align:start position:0% +stronger when they're more + + + align:start position:0% +stronger when they're more +um friends on the field uh for a + + align:start position:0% +um friends on the field uh for a + + + align:start position:0% +um friends on the field uh for a +particular worker + + align:start position:0% +particular worker + + + align:start position:0% +particular worker +second however it's also like a repeated + + align:start position:0% +second however it's also like a repeated + + + align:start position:0% +second however it's also like a repeated +game that is to say + + align:start position:0% +game that is to say + + + align:start position:0% +game that is to say +the the sort of a low effort equilibrium + + align:start position:0% +the the sort of a low effort equilibrium + + + align:start position:0% +the the sort of a low effort equilibrium +where essentially if there's relative + + align:start position:0% +where essentially if there's relative + + + align:start position:0% +where essentially if there's relative +pay + + align:start position:0% +pay + + + align:start position:0% +pay +we can just all agree everybody on the + + align:start position:0% +we can just all agree everybody on the + + + align:start position:0% +we can just all agree everybody on the +field might sort of agree that not + + align:start position:0% +field might sort of agree that not + + + align:start position:0% +field might sort of agree that not +working particularly hard + + align:start position:0% +working particularly hard + + + align:start position:0% +working particularly hard +is uh is a good idea because we are + + align:start position:0% +is uh is a good idea because we are + + + align:start position:0% +is uh is a good idea because we are +essentially paid relatively anyway + + align:start position:0% +essentially paid relatively anyway + + + align:start position:0% +essentially paid relatively anyway +so if everybody doubles their effort + + align:start position:0% +so if everybody doubles their effort + + + align:start position:0% +so if everybody doubles their effort +nothing is going to pay + + align:start position:0% +nothing is going to pay + + + align:start position:0% +nothing is going to pay +there's nothing that's going to happen + + align:start position:0% +there's nothing that's going to happen + + + align:start position:0% +there's nothing that's going to happen +to workers compensation + + align:start position:0% +to workers compensation + + + align:start position:0% +to workers compensation +so you might as well just decide + + align:start position:0% +so you might as well just decide + + + align:start position:0% +so you might as well just decide +everybody could just decide work half as + + align:start position:0% +everybody could just decide work half as + + + align:start position:0% +everybody could just decide work half as +hard + + align:start position:0% +hard + + + align:start position:0% +hard +and we're going to be paid the same and + + align:start position:0% +and we're going to be paid the same and + + + align:start position:0% +and we're going to be paid the same and +as long as we sort of can + + align:start position:0% +as long as we sort of can + + + align:start position:0% +as long as we sort of can +sustain at equilibrium that's a good + + align:start position:0% +sustain at equilibrium that's a good + + + align:start position:0% +sustain at equilibrium that's a good +idea + + align:start position:0% +idea + + + align:start position:0% +idea +of course in any given period + + align:start position:0% +of course in any given period + + + align:start position:0% +of course in any given period +any given worker might have the + + align:start position:0% +any given worker might have the + + + align:start position:0% +any given worker might have the +incentives to deviate from this + + align:start position:0% +incentives to deviate from this + + + align:start position:0% +incentives to deviate from this +equilibrium + + align:start position:0% +equilibrium + + + align:start position:0% +equilibrium +because on any given day if you work + + align:start position:0% +because on any given day if you work + + + align:start position:0% +because on any given day if you work +really hard you're going to be paid a + + align:start position:0% +really hard you're going to be paid a + + + align:start position:0% +really hard you're going to be paid a +lot more + + align:start position:0% +lot more + + + align:start position:0% +lot more +for that today and so um + + align:start position:0% +for that today and so um + + + align:start position:0% +for that today and so um +how might we be able to disentangle that + + align:start position:0% +how might we be able to disentangle that + + + align:start position:0% +how might we be able to disentangle that +well um what bandiera + + align:start position:0% +well um what bandiera + + + align:start position:0% +well um what bandiera +have is they have also some variation in + + align:start position:0% +have is they have also some variation in + + + align:start position:0% +have is they have also some variation in +the types of fruits that + + align:start position:0% +the types of fruits that + + + align:start position:0% +the types of fruits that +were collected what do i mean by that + + align:start position:0% +were collected what do i mean by that + + + align:start position:0% +were collected what do i mean by that +well if you think about what you need to + + align:start position:0% +well if you think about what you need to + + + align:start position:0% +well if you think about what you need to +be able to + + align:start position:0% +be able to + + + align:start position:0% +be able to +disentangle these what you might want to + + align:start position:0% +disentangle these what you might want to + + + align:start position:0% +disentangle these what you might want to +have is like differences in the + + align:start position:0% +have is like differences in the + + + align:start position:0% +have is like differences in the +observability of effort right so if i + + align:start position:0% +observability of effort right so if i + + + align:start position:0% +observability of effort right so if i +can + + align:start position:0% +can + + + align:start position:0% +can +see what my co-worker does i can like + + align:start position:0% +see what my co-worker does i can like + + + align:start position:0% +see what my co-worker does i can like +punish them very effectively i can just + + align:start position:0% +punish them very effectively i can just + + + align:start position:0% +punish them very effectively i can just +know like whenever um + + align:start position:0% +know like whenever um + + + align:start position:0% +know like whenever um +frank is working really hard my + + align:start position:0% +frank is working really hard my + + + align:start position:0% +frank is working really hard my +co-workers might + + align:start position:0% +co-workers might + + + align:start position:0% +co-workers might +want to punish me um and then it's very + + align:start position:0% +want to punish me um and then it's very + + + align:start position:0% +want to punish me um and then it's very +hard for me to work really hard because + + align:start position:0% +hard for me to work really hard because + + + align:start position:0% +hard for me to work really hard because +you know i'm getting trouble at night + + align:start position:0% +you know i'm getting trouble at night + + + align:start position:0% +you know i'm getting trouble at night +after work with my co-workers or the + + align:start position:0% +after work with my co-workers or the + + + align:start position:0% +after work with my co-workers or the +next day everybody might also work + + align:start position:0% +next day everybody might also work + + + align:start position:0% +next day everybody might also work +really hard and i kind of don't want + + align:start position:0% +really hard and i kind of don't want + + + align:start position:0% +really hard and i kind of don't want +that + + align:start position:0% +that + + + align:start position:0% +that +on the other hand if i can hide how hard + + align:start position:0% +on the other hand if i can hide how hard + + + align:start position:0% +on the other hand if i can hide how hard +i'm working well then you know + + align:start position:0% +i'm working well then you know + + + align:start position:0% +i'm working well then you know +i might secretly work really hard and my + + align:start position:0% +i might secretly work really hard and my + + + align:start position:0% +i might secretly work really hard and my +co-workers might not even + + align:start position:0% +co-workers might not even + + + align:start position:0% +co-workers might not even +find out so then um if that's the case + + align:start position:0% +find out so then um if that's the case + + + align:start position:0% +find out so then um if that's the case +in the repeated game um the repeated + + align:start position:0% +in the repeated game um the repeated + + + align:start position:0% +in the repeated game um the repeated +game equilibrium might not just be + + align:start position:0% +game equilibrium might not just be + + + align:start position:0% +game equilibrium might not just be +might just not be enforceable as in like + + align:start position:0% +might just not be enforceable as in like + + + align:start position:0% +might just not be enforceable as in like +i might just tell my friends oh i wasn't + + align:start position:0% +i might just tell my friends oh i wasn't + + + align:start position:0% +i might just tell my friends oh i wasn't +really working hard but in fact i was + + align:start position:0% +really working hard but in fact i was + + + align:start position:0% +really working hard but in fact i was +and like + + align:start position:0% +and like + + + align:start position:0% +and like +they have no way of finding out because + + align:start position:0% +they have no way of finding out because + + + align:start position:0% +they have no way of finding out because +i was sort of + + align:start position:0% +i was sort of + + + align:start position:0% +i was sort of +unobservable if instead i really care + + align:start position:0% +unobservable if instead i really care + + + align:start position:0% +unobservable if instead i really care +about them if i'm really interested in + + align:start position:0% +about them if i'm really interested in + + + align:start position:0% +about them if i'm really interested in +their + + align:start position:0% +their + + + align:start position:0% +their +um in their well-being overall in their + + align:start position:0% +um in their well-being overall in their + + + align:start position:0% +um in their well-being overall in their +payment + + align:start position:0% +payment + + + align:start position:0% +payment +it doesn't matter whether my effort is + + align:start position:0% +it doesn't matter whether my effort is + + + align:start position:0% +it doesn't matter whether my effort is +observable regardless of how observable + + align:start position:0% +observable regardless of how observable + + + align:start position:0% +observable regardless of how observable +my effort is i will not work really very + + align:start position:0% +my effort is i will not work really very + + + align:start position:0% +my effort is i will not work really very +hard because not working hard makes them + + align:start position:0% +hard because not working hard makes them + + + align:start position:0% +hard because not working hard makes them +better off + + align:start position:0% +better off + + + align:start position:0% +better off +so if you just had some differences in + + align:start position:0% +so if you just had some differences in + + + align:start position:0% +so if you just had some differences in +observability + + align:start position:0% +observability + + + align:start position:0% +observability +in effort how hard people work we could + + align:start position:0% +in effort how hard people work we could + + + align:start position:0% +in effort how hard people work we could +just + + align:start position:0% +just + + + align:start position:0% +just +disentangle these two um explanations + + align:start position:0% +disentangle these two um explanations + + + align:start position:0% +disentangle these two um explanations +so um bandiera and i'll have this very + + align:start position:0% +so um bandiera and i'll have this very + + + align:start position:0% +so um bandiera and i'll have this very +nice variation they have + + align:start position:0% +nice variation they have + + + align:start position:0% +nice variation they have +two fruits they're fruit type one which + + align:start position:0% +two fruits they're fruit type one which + + + align:start position:0% +two fruits they're fruit type one which +are strawberries + + align:start position:0% +are strawberries + + + align:start position:0% +are strawberries +and they have fruit of type two which + + align:start position:0% +and they have fruit of type two which + + + align:start position:0% +and they have fruit of type two which +are raspberries + + align:start position:0% +are raspberries + + + align:start position:0% +are raspberries +if you ever have picked strawberries you + + align:start position:0% +if you ever have picked strawberries you + + + align:start position:0% +if you ever have picked strawberries you +would know that + + align:start position:0% +would know that + + + align:start position:0% +would know that +strawberries it's very easy these are + + align:start position:0% +strawberries it's very easy these are + + + align:start position:0% +strawberries it's very easy these are +like essentially very flat + + align:start position:0% +like essentially very flat + + + align:start position:0% +like essentially very flat +and low fruit that when somebody picks + + align:start position:0% +and low fruit that when somebody picks + + + align:start position:0% +and low fruit that when somebody picks +strawberries it's very easy to see how + + align:start position:0% +strawberries it's very easy to see how + + + align:start position:0% +strawberries it's very easy to see how +fast somebody works how much + + align:start position:0% +fast somebody works how much + + + align:start position:0% +fast somebody works how much +anybody picks and so on because you can + + align:start position:0% +anybody picks and so on because you can + + + align:start position:0% +anybody picks and so on because you can +just see across the entire field you can + + align:start position:0% +just see across the entire field you can + + + align:start position:0% +just see across the entire field you can +see essentially what all of your + + align:start position:0% +see essentially what all of your + + + align:start position:0% +see essentially what all of your +co-workers are doing + + align:start position:0% +co-workers are doing + + + align:start position:0% +co-workers are doing +in contrast if you look at strawberries + + align:start position:0% +in contrast if you look at strawberries + + + align:start position:0% +in contrast if you look at strawberries +sorry if you look at raspberries these + + align:start position:0% +sorry if you look at raspberries these + + + align:start position:0% +sorry if you look at raspberries these +are bushes so you can essentially + + align:start position:0% +are bushes so you can essentially + + + align:start position:0% +are bushes so you can essentially +literally hide behind the boat hide + + align:start position:0% +literally hide behind the boat hide + + + align:start position:0% +literally hide behind the boat hide +behind the bushes and work really hard + + align:start position:0% +behind the bushes and work really hard + + + align:start position:0% +behind the bushes and work really hard +to pick really hard + + align:start position:0% +to pick really hard + + + align:start position:0% +to pick really hard +and fast without others noticing so + + align:start position:0% +and fast without others noticing so + + + align:start position:0% +and fast without others noticing so +essentially productivity + + align:start position:0% +essentially productivity + + + align:start position:0% +essentially productivity +is at least more unobserved than for + + align:start position:0% +is at least more unobserved than for + + + align:start position:0% +is at least more unobserved than for +strawberries now what bundier at all + + align:start position:0% +strawberries now what bundier at all + + + align:start position:0% +strawberries now what bundier at all +then find in fact is no impact of the + + align:start position:0% +then find in fact is no impact of the + + + align:start position:0% +then find in fact is no impact of the +piece rate on fruits + + align:start position:0% +piece rate on fruits + + + align:start position:0% +piece rate on fruits +of type type 2 which is raspberries + + align:start position:0% +of type type 2 which is raspberries + + + align:start position:0% +of type type 2 which is raspberries +so that sort of suggests there is no + + align:start position:0% +so that sort of suggests there is no + + + align:start position:0% +so that sort of suggests there is no +evidence of pure altruism + + align:start position:0% +evidence of pure altruism + + + align:start position:0% +evidence of pure altruism +and the effects perhaps could be driven + + align:start position:0% +and the effects perhaps could be driven + + + align:start position:0% +and the effects perhaps could be driven +by um + + align:start position:0% +by um + + + align:start position:0% +by um +reciprocity this is kind of consistent + + align:start position:0% +reciprocity this is kind of consistent + + + align:start position:0% +reciprocity this is kind of consistent +with what we had found before + + align:start position:0% +with what we had found before + + + align:start position:0% +with what we had found before +when you remember the dictator ultimatum + + align:start position:0% +when you remember the dictator ultimatum + + + align:start position:0% +when you remember the dictator ultimatum +games that we showed you + + align:start position:0% +games that we showed you + + + align:start position:0% +games that we showed you +it looked a lot like people are + + align:start position:0% +it looked a lot like people are + + + align:start position:0% +it looked a lot like people are +altruistic they care about others + + align:start position:0% +altruistic they care about others + + + align:start position:0% +altruistic they care about others +but when you look at their actual + + align:start position:0% +but when you look at their actual + + + align:start position:0% +but when you look at their actual +motives when you look at little when you + + align:start position:0% +motives when you look at little when you + + + align:start position:0% +motives when you look at little when you +dig a little deeper we find out that in + + align:start position:0% +dig a little deeper we find out that in + + + align:start position:0% +dig a little deeper we find out that in +fact + + align:start position:0% +fact + + + align:start position:0% +fact +this is driven uh by reciprocity or by + + align:start position:0% +this is driven uh by reciprocity or by + + + align:start position:0% +this is driven uh by reciprocity or by +worries about repeated game effects + + align:start position:0% +worries about repeated game effects + + + align:start position:0% +worries about repeated game effects +or worries about essentially just + + align:start position:0% +or worries about essentially just + + + align:start position:0% +or worries about essentially just +retribution either on the field that + + align:start position:0% +retribution either on the field that + + + align:start position:0% +retribution either on the field that +you know other people will work also + + align:start position:0% +you know other people will work also + + + align:start position:0% +you know other people will work also +really hard if i will work really hard + + align:start position:0% +really hard if i will work really hard + + + align:start position:0% +really hard if i will work really hard +right now + + align:start position:0% +right now + + + align:start position:0% +right now +or you know socially after work my + + align:start position:0% +or you know socially after work my + + + align:start position:0% +or you know socially after work my +co-workers might be really mean to me + + align:start position:0% +co-workers might be really mean to me + + + align:start position:0% +co-workers might be really mean to me +they might even beat me up or they might + + align:start position:0% +they might even beat me up or they might + + + align:start position:0% +they might even beat me up or they might +not be my friends um anymore + + align:start position:0% +not be my friends um anymore + + + align:start position:0% +not be my friends um anymore +and this is um um here so the regression + + align:start position:0% +and this is um um here so the regression + + + align:start position:0% +and this is um um here so the regression +tables that show you this + + align:start position:0% +tables that show you this + + + align:start position:0% +tables that show you this +the first column you see fruit type 2. + + align:start position:0% +the first column you see fruit type 2. + + + align:start position:0% +the first column you see fruit type 2. +again these are the raspberries this is + + align:start position:0% +again these are the raspberries this is + + + align:start position:0% +again these are the raspberries this is +when things are + + align:start position:0% +when things are + + + align:start position:0% +when things are +unobserved there's no effect of + + align:start position:0% +unobserved there's no effect of + + + align:start position:0% +unobserved there's no effect of +introducing the piece rate + + align:start position:0% +introducing the piece rate + + + align:start position:0% +introducing the piece rate +in contrast if you look at column two + + align:start position:0% +in contrast if you look at column two + + + align:start position:0% +in contrast if you look at column two +this is fruit type + + align:start position:0% +this is fruit type + + + align:start position:0% +this is fruit type +one these are strawberries and there's + + align:start position:0% +one these are strawberries and there's + + + align:start position:0% +one these are strawberries and there's +large productivity effects of + + align:start position:0% +large productivity effects of + + + align:start position:0% +large productivity effects of +strawberries + + align:start position:0% +strawberries + + + align:start position:0% +strawberries +there so these results again highlight + + align:start position:0% +there so these results again highlight + + + align:start position:0% +there so these results again highlight +the importance of + + align:start position:0% +the importance of + + + align:start position:0% +the importance of +setting the incentives carefully small + + align:start position:0% +setting the incentives carefully small + + + align:start position:0% +setting the incentives carefully small +details matter and you really want to be + + align:start position:0% +details matter and you really want to be + + + align:start position:0% +details matter and you really want to be +very careful and like how you said + + align:start position:0% +very careful and like how you said + + + align:start position:0% +very careful and like how you said +relative incentives + + align:start position:0% +relative incentives + + + align:start position:0% +relative incentives +that in principle seem like a good idea + + align:start position:0% +that in principle seem like a good idea + + + align:start position:0% +that in principle seem like a good idea +because they sort of provide steep + + align:start position:0% +because they sort of provide steep + + + align:start position:0% +because they sort of provide steep +incentives to workers + + align:start position:0% +incentives to workers + + + align:start position:0% +incentives to workers +but in practice might actually not work + + align:start position:0% +but in practice might actually not work + + + align:start position:0% +but in practice might actually not work +particularly well + + align:start position:0% + + + + align:start position:0% + +okay so the second paper we're going to + + align:start position:0% +okay so the second paper we're going to + + + align:start position:0% +okay so the second paper we're going to +look at is brazil these are the morale + + align:start position:0% +look at is brazil these are the morale + + + align:start position:0% +look at is brazil these are the morale +effects of pay inequality + + align:start position:0% +effects of pay inequality + + + align:start position:0% +effects of pay inequality +this is a very nice randomized field + + align:start position:0% +this is a very nice randomized field + + + align:start position:0% +this is a very nice randomized field +experiment in rural india with lower + + align:start position:0% +experiment in rural india with lower + + + align:start position:0% +experiment in rural india with lower +skill + + align:start position:0% +skill + + + align:start position:0% +skill +manufacturing workers the question the + + align:start position:0% +manufacturing workers the question the + + + align:start position:0% +manufacturing workers the question the +authors ask + + align:start position:0% +authors ask + + + align:start position:0% +authors ask +is do workers care about relative pay + + align:start position:0% +is do workers care about relative pay + + + align:start position:0% +is do workers care about relative pay +and perhaps why do we see so little + + align:start position:0% +and perhaps why do we see so little + + + align:start position:0% +and perhaps why do we see so little +variation in pay across settings so what + + align:start position:0% +variation in pay across settings so what + + + align:start position:0% +variation in pay across settings so what +we often see in many companies + + align:start position:0% +we often see in many companies + + + align:start position:0% +we often see in many companies +in india but also in other places also + + align:start position:0% +in india but also in other places also + + + align:start position:0% +in india but also in other places also +in + + align:start position:0% +in + + + align:start position:0% +in +certain villages in india what we see is + + align:start position:0% +certain villages in india what we see is + + + align:start position:0% +certain villages in india what we see is +wages tend to be very compressed + + align:start position:0% +wages tend to be very compressed + + + align:start position:0% +wages tend to be very compressed +so workers essentially earn the exact + + align:start position:0% +so workers essentially earn the exact + + + align:start position:0% +so workers essentially earn the exact +same wage + + align:start position:0% +same wage + + + align:start position:0% +same wage +regardless of their um underlying + + align:start position:0% +regardless of their um underlying + + + align:start position:0% +regardless of their um underlying +productivity + + align:start position:0% +productivity + + + align:start position:0% +productivity +experience and so on good and bad + + align:start position:0% +experience and so on good and bad + + + align:start position:0% +experience and so on good and bad +workers tend to work exactly + + align:start position:0% +workers tend to work exactly + + + align:start position:0% +workers tend to work exactly +tend to earn exactly the same amount of + + align:start position:0% +tend to earn exactly the same amount of + + + align:start position:0% +tend to earn exactly the same amount of +money + + align:start position:0% +money + + + align:start position:0% +money +for per day or per hour and the like + + align:start position:0% +for per day or per hour and the like + + + align:start position:0% +for per day or per hour and the like +economists think that's inefficient + + align:start position:0% +economists think that's inefficient + + + align:start position:0% +economists think that's inefficient +because you know if you want to hire + + align:start position:0% +because you know if you want to hire + + + align:start position:0% +because you know if you want to hire +somebody who's really really productive + + align:start position:0% +somebody who's really really productive + + + align:start position:0% +somebody who's really really productive +you might want to hire pay them more + + align:start position:0% +you might want to hire pay them more + + + align:start position:0% +you might want to hire pay them more +if you want to hire somebody who's not + + align:start position:0% +if you want to hire somebody who's not + + + align:start position:0% +if you want to hire somebody who's not +that productive you might want to pay + + align:start position:0% +that productive you might want to pay + + + align:start position:0% +that productive you might want to pay +them less + + align:start position:0% +them less + + + align:start position:0% +them less +you might actually want to pay them less + + align:start position:0% +you might actually want to pay them less + + + align:start position:0% +you might actually want to pay them less +than the prevailing wage + + align:start position:0% +than the prevailing wage + + + align:start position:0% +than the prevailing wage +but you might not be able to do so + + align:start position:0% +but you might not be able to do so + + + align:start position:0% +but you might not be able to do so +because the norm is that + + align:start position:0% +because the norm is that + + + align:start position:0% +because the norm is that +you have to pay them the prevailing wage + + align:start position:0% +you have to pay them the prevailing wage + + + align:start position:0% +you have to pay them the prevailing wage +and then you might end up + + align:start position:0% +and then you might end up + + + align:start position:0% +and then you might end up +not hiring that person and that person + + align:start position:0% +not hiring that person and that person + + + align:start position:0% +not hiring that person and that person +might end up being unemployed + + align:start position:0% +might end up being unemployed + + + align:start position:0% +might end up being unemployed +even though it would you would be very + + align:start position:0% +even though it would you would be very + + + align:start position:0% +even though it would you would be very +happy to to pay them at a lower wage + + align:start position:0% +happy to to pay them at a lower wage + + + align:start position:0% +happy to to pay them at a lower wage +this is really a really relevant + + align:start position:0% +this is really a really relevant + + + align:start position:0% +this is really a really relevant +question or sorry there's a second + + align:start position:0% +question or sorry there's a second + + + align:start position:0% +question or sorry there's a second +question the authors ask is + + align:start position:0% +question the authors ask is + + + align:start position:0% +question the authors ask is +what is the notion of the underlying + + align:start position:0% +what is the notion of the underlying + + + align:start position:0% +what is the notion of the underlying +notion of fairness + + align:start position:0% +notion of fairness + + + align:start position:0% +notion of fairness +what is kind of a fair and what's not + + align:start position:0% +what is kind of a fair and what's not + + + align:start position:0% +what is kind of a fair and what's not +fair as in like + + align:start position:0% +fair as in like + + + align:start position:0% +fair as in like +if there is wage dispersion across + + align:start position:0% +if there is wage dispersion across + + + align:start position:0% +if there is wage dispersion across +workers + + align:start position:0% +workers + + + align:start position:0% +workers +within teams or within a certain for our + + align:start position:0% +within teams or within a certain for our + + + align:start position:0% +within teams or within a certain for our +firm are there some circumstances under + + align:start position:0% +firm are there some circumstances under + + + align:start position:0% +firm are there some circumstances under +which that's okay to do are there some + + align:start position:0% +which that's okay to do are there some + + + align:start position:0% +which that's okay to do are there some +good justification that workers are + + align:start position:0% +good justification that workers are + + + align:start position:0% +good justification that workers are +uh okay with or in contrast + + align:start position:0% +uh okay with or in contrast + + + align:start position:0% +uh okay with or in contrast +or uh is it just always bad to do so so + + align:start position:0% +or uh is it just always bad to do so so + + + align:start position:0% +or uh is it just always bad to do so so +can we sort of find some situation on + + align:start position:0% +can we sort of find some situation on + + + align:start position:0% +can we sort of find some situation on +which under which + + align:start position:0% +which under which + + + align:start position:0% +which under which +uh it's justified for workers or not or + + align:start position:0% +uh it's justified for workers or not or + + + align:start position:0% +uh it's justified for workers or not or +is it just like we cannot pay half pay + + align:start position:0% +is it just like we cannot pay half pay + + + align:start position:0% +is it just like we cannot pay half pay +inequality under any circumstances + + align:start position:0% +inequality under any circumstances + + + align:start position:0% +inequality under any circumstances +in those kinds of firms this is + + align:start position:0% +in those kinds of firms this is + + + align:start position:0% +in those kinds of firms this is +potentially quite relevant for + + align:start position:0% +potentially quite relevant for + + + align:start position:0% +potentially quite relevant for +many features of the labor market it + + align:start position:0% +many features of the labor market it + + + align:start position:0% +many features of the labor market it +might explain + + align:start position:0% +might explain + + + align:start position:0% +might explain +wage compression that's what i'm saying + + align:start position:0% +wage compression that's what i'm saying + + + align:start position:0% +wage compression that's what i'm saying +like words tend to be fairly compressed + + align:start position:0% +like words tend to be fairly compressed + + + align:start position:0% +like words tend to be fairly compressed +even if productivity is fairly dispersed + + align:start position:0% +even if productivity is fairly dispersed + + + align:start position:0% +even if productivity is fairly dispersed +across workers + + align:start position:0% +across workers + + + align:start position:0% +across workers +there tends to be lots of wage rigidity + + align:start position:0% +there tends to be lots of wage rigidity + + + align:start position:0% +there tends to be lots of wage rigidity +wages tend to not move very much + + align:start position:0% +wages tend to not move very much + + + align:start position:0% +wages tend to not move very much +it seems to be employers have trouble um + + align:start position:0% +it seems to be employers have trouble um + + + align:start position:0% +it seems to be employers have trouble um +adjusting wages or they are reluctant to + + align:start position:0% +adjusting wages or they are reluctant to + + + align:start position:0% +adjusting wages or they are reluctant to +adjust people's wages much in particular + + align:start position:0% +adjust people's wages much in particular + + + align:start position:0% +adjust people's wages much in particular +when it comes to like downward rigidity + + align:start position:0% +when it comes to like downward rigidity + + + align:start position:0% +when it comes to like downward rigidity +we talked about this a little bit + + align:start position:0% +we talked about this a little bit + + + align:start position:0% +we talked about this a little bit +already + + align:start position:0% +already + + + align:start position:0% +already +when we talked about reference + + align:start position:0% +when we talked about reference + + + align:start position:0% +when we talked about reference +dependence um we can also think that + + align:start position:0% +dependence um we can also think that + + + align:start position:0% +dependence um we can also think that +help this can help us think about like + + align:start position:0% +help this can help us think about like + + + align:start position:0% +help this can help us think about like +sorting of workers into firms and + + align:start position:0% +sorting of workers into firms and + + + align:start position:0% +sorting of workers into firms and +inequality + + align:start position:0% +inequality + + + align:start position:0% +inequality +uh we can think about firm boundaries in + + align:start position:0% +uh we can think about firm boundaries in + + + align:start position:0% +uh we can think about firm boundaries in +a sense to say like + + align:start position:0% +a sense to say like + + + align:start position:0% +a sense to say like +should they be really large firms or a + + align:start position:0% +should they be really large firms or a + + + align:start position:0% +should they be really large firms or a +number of small firms + + align:start position:0% +number of small firms + + + align:start position:0% +number of small firms +if you think the relative comparison is + + align:start position:0% +if you think the relative comparison is + + + align:start position:0% +if you think the relative comparison is +uh across workers within firms that + + align:start position:0% +uh across workers within firms that + + + align:start position:0% +uh across workers within firms that +would sort of say well we should + + align:start position:0% +would sort of say well we should + + + align:start position:0% +would sort of say well we should +probably + + align:start position:0% +probably + + + align:start position:0% +probably +have a lot of small firms and then each + + align:start position:0% +have a lot of small firms and then each + + + align:start position:0% +have a lot of small firms and then each +of these small firms could have + + align:start position:0% +of these small firms could have + + + align:start position:0% +of these small firms could have +different wages + + align:start position:0% +different wages + + + align:start position:0% +different wages +as opposed to like one large firm where + + align:start position:0% +as opposed to like one large firm where + + + align:start position:0% +as opposed to like one large firm where +like essentially everybody has to be + + align:start position:0% +like essentially everybody has to be + + + align:start position:0% +like essentially everybody has to be +paid more or less + + align:start position:0% +paid more or less + + + align:start position:0% +paid more or less +the same and we might think that's + + align:start position:0% +the same and we might think that's + + + align:start position:0% +the same and we might think that's +inefficient because there's returns to + + align:start position:0% +inefficient because there's returns to + + + align:start position:0% +inefficient because there's returns to +scale of having like a large + + align:start position:0% +scale of having like a large + + + align:start position:0% +scale of having like a large +um firm think about us that is also + + align:start position:0% +um firm think about us that is also + + + align:start position:0% +um firm think about us that is also +relevant for some hr + + align:start position:0% +relevant for some hr + + + align:start position:0% +relevant for some hr +policies in terms of like how do you pay + + align:start position:0% +policies in terms of like how do you pay + + + align:start position:0% +policies in terms of like how do you pay +workers how do you set wages and so on + + align:start position:0% +workers how do you set wages and so on + + + align:start position:0% +workers how do you set wages and so on +so as motivation in a study the authors + + align:start position:0% +so as motivation in a study the authors + + + align:start position:0% +so as motivation in a study the authors +ask people the certain + + align:start position:0% +ask people the certain + + + align:start position:0% +ask people the certain +the following questions the question is + + align:start position:0% +the following questions the question is + + + align:start position:0% +the following questions the question is +the following + + align:start position:0% +the following + + + align:start position:0% +the following +three this is rural india and rissa + + align:start position:0% +three this is rural india and rissa + + + align:start position:0% +three this is rural india and rissa +a relatively poor area + + align:start position:0% +a relatively poor area + + + align:start position:0% +a relatively poor area +with lots of small scale manufacturing + + align:start position:0% +with lots of small scale manufacturing + + + align:start position:0% +with lots of small scale manufacturing +the question is three people from a + + align:start position:0% +the question is three people from a + + + align:start position:0% +the question is three people from a +village get hired to work on a + + align:start position:0% +village get hired to work on a + + + align:start position:0% +village get hired to work on a +construction site together + + align:start position:0% +construction site together + + + align:start position:0% +construction site together +the prevailing wage is 250 rupees in the + + align:start position:0% +the prevailing wage is 250 rupees in the + + + align:start position:0% +the prevailing wage is 250 rupees in the +village that's kind of the standard wage + + align:start position:0% +village that's kind of the standard wage + + + align:start position:0% +village that's kind of the standard wage +in the village each village tends to + + align:start position:0% +in the village each village tends to + + + align:start position:0% +in the village each village tends to +have like a prevailing weight which is + + align:start position:0% +have like a prevailing weight which is + + + align:start position:0% +have like a prevailing weight which is +like how much people are paid usually + + align:start position:0% +like how much people are paid usually + + + align:start position:0% +like how much people are paid usually +the contractor pays them uh 200 250 + + align:start position:0% +the contractor pays them uh 200 250 + + + align:start position:0% +the contractor pays them uh 200 250 +rupees per day + + align:start position:0% +rupees per day + + + align:start position:0% +rupees per day +how well will they work together and + + align:start position:0% +how well will they work together and + + + align:start position:0% +how well will they work together and +what you see is what respondents tend to + + align:start position:0% +what you see is what respondents tend to + + + align:start position:0% +what you see is what respondents tend to +say is like 80 percent of respondents + + align:start position:0% +say is like 80 percent of respondents + + + align:start position:0% +say is like 80 percent of respondents +say + + align:start position:0% +say + + + align:start position:0% +say +uh uh people work very well together + + align:start position:0% +uh uh people work very well together + + + align:start position:0% +uh uh people work very well together +uh 20 say as well as usual and zero + + align:start position:0% +uh 20 say as well as usual and zero + + + align:start position:0% +uh 20 say as well as usual and zero +percent say there will be conflict so + + align:start position:0% +percent say there will be conflict so + + + align:start position:0% +percent say there will be conflict so +that's kind of like seems like paying + + align:start position:0% +that's kind of like seems like paying + + + align:start position:0% +that's kind of like seems like paying +everybody the same + + align:start position:0% +everybody the same + + + align:start position:0% +everybody the same +is a socially acceptable thing to do + + align:start position:0% +is a socially acceptable thing to do + + + align:start position:0% +is a socially acceptable thing to do +everybody seems happy + + align:start position:0% +everybody seems happy + + + align:start position:0% +everybody seems happy +with that in contrast if you ask the + + align:start position:0% +with that in contrast if you ask the + + + align:start position:0% +with that in contrast if you ask the +following which is the contractor pays + + align:start position:0% +following which is the contractor pays + + + align:start position:0% +following which is the contractor pays +them different + + align:start position:0% +them different + + + align:start position:0% +them different +wages if the contractor tractor pays 250 + + align:start position:0% +wages if the contractor tractor pays 250 + + + align:start position:0% +wages if the contractor tractor pays 250 +per day to 70 percent and put 290 per + + align:start position:0% +per day to 70 percent and put 290 per + + + align:start position:0% +per day to 70 percent and put 290 per +day + + align:start position:0% +day + + + align:start position:0% +day +how well will they work together + + align:start position:0% +how well will they work together + + + align:start position:0% +how well will they work together +and so now um what you see here is when + + align:start position:0% +and so now um what you see here is when + + + align:start position:0% +and so now um what you see here is when +there's differences + + align:start position:0% +there's differences + + + align:start position:0% +there's differences +are cross pay 94 percent of workers + + align:start position:0% +are cross pay 94 percent of workers + + + align:start position:0% +are cross pay 94 percent of workers +say there will be conflict now it + + align:start position:0% +say there will be conflict now it + + + align:start position:0% +say there will be conflict now it +doesn't specify here at least in this + + align:start position:0% +doesn't specify here at least in this + + + align:start position:0% +doesn't specify here at least in this +version of the question it doesn't + + align:start position:0% +version of the question it doesn't + + + align:start position:0% +version of the question it doesn't +specify + + align:start position:0% +specify + + + align:start position:0% +specify +whether that's to do with like + + align:start position:0% +whether that's to do with like + + + align:start position:0% +whether that's to do with like +underlying productivity differences so + + align:start position:0% +underlying productivity differences so + + + align:start position:0% +underlying productivity differences so +why is it that some workers are paid + + align:start position:0% +why is it that some workers are paid + + + align:start position:0% +why is it that some workers are paid +different than others + + align:start position:0% +different than others + + + align:start position:0% +different than others +however it's very strong suggestive + + align:start position:0% +however it's very strong suggestive + + + align:start position:0% +however it's very strong suggestive +evidence that + + align:start position:0% +evidence that + + + align:start position:0% +evidence that +workers might be really unhappy and + + align:start position:0% +workers might be really unhappy and + + + align:start position:0% +workers might be really unhappy and +there will be conflict across workers + + align:start position:0% +there will be conflict across workers + + + align:start position:0% +there will be conflict across workers +if they pay different wages in the same + + align:start position:0% +if they pay different wages in the same + + + align:start position:0% +if they pay different wages in the same +kind of + + align:start position:0% +kind of + + + align:start position:0% +kind of +team or at least on the same + + align:start position:0% +team or at least on the same + + + align:start position:0% +team or at least on the same +construction site + + align:start position:0% +construction site + + + align:start position:0% +construction site +and then okay of course if you're like + + align:start position:0% +and then okay of course if you're like + + + align:start position:0% +and then okay of course if you're like +an employer you might be quite worried + + align:start position:0% +an employer you might be quite worried + + + align:start position:0% +an employer you might be quite worried +about paying people different wages + + align:start position:0% +about paying people different wages + + + align:start position:0% +about paying people different wages +because if there's conflict presumably + + align:start position:0% +because if there's conflict presumably + + + align:start position:0% +because if there's conflict presumably +workers will not work + + align:start position:0% +workers will not work + + + align:start position:0% +workers will not work +or collaborate as well as they could + + align:start position:0% +or collaborate as well as they could + + + align:start position:0% +or collaborate as well as they could +potentially + + align:start position:0% +potentially + + + align:start position:0% +potentially +okay so now the author set up a very + + align:start position:0% +okay so now the author set up a very + + + align:start position:0% +okay so now the author set up a very +nice field experiment that looks like + + align:start position:0% +nice field experiment that looks like + + + align:start position:0% +nice field experiment that looks like +this + + align:start position:0% +this + + + align:start position:0% +this +so there's 10 production units of three + + align:start position:0% +so there's 10 production units of three + + + align:start position:0% +so there's 10 production units of three +workers each + + align:start position:0% +workers each + + + align:start position:0% +workers each +in each factory so think of factories + + align:start position:0% +in each factory so think of factories + + + align:start position:0% +in each factory so think of factories +like work sites + + align:start position:0% +like work sites + + + align:start position:0% +like work sites +factories and parenthood and quotation + + align:start position:0% +factories and parenthood and quotation + + + align:start position:0% +factories and parenthood and quotation +marks because it's really not just a + + align:start position:0% +marks because it's really not just a + + + align:start position:0% +marks because it's really not just a +factory as you might sort of imagine it + + align:start position:0% +factory as you might sort of imagine it + + + align:start position:0% +factory as you might sort of imagine it +it's really like a small work site an + + align:start position:0% +it's really like a small work site an + + + align:start position:0% +it's really like a small work site an +office where people are working in + + align:start position:0% +office where people are working in + + + align:start position:0% +office where people are working in +different areas + + align:start position:0% +different areas + + + align:start position:0% +different areas +there's 10 units of three workers each + + align:start position:0% +there's 10 units of three workers each + + + align:start position:0% +there's 10 units of three workers each +so it's not a huge office + + align:start position:0% +so it's not a huge office + + + align:start position:0% +so it's not a huge office +each unit of three workers produces + + align:start position:0% +each unit of three workers produces + + + align:start position:0% +each unit of three workers produces +different products so like each unit has + + align:start position:0% +different products so like each unit has + + + align:start position:0% +different products so like each unit has +like one + + align:start position:0% +like one + + + align:start position:0% +like one +product for example unit one makes + + align:start position:0% +product for example unit one makes + + + align:start position:0% +product for example unit one makes +brooms unit two makes + + align:start position:0% +brooms unit two makes + + + align:start position:0% +brooms unit two makes +incense sticks union 3 makes + + align:start position:0% +incense sticks union 3 makes + + + align:start position:0% +incense sticks union 3 makes +leaf plates and so on so each unit has + + align:start position:0% +leaf plates and so on so each unit has + + + align:start position:0% +leaf plates and so on so each unit has +like one + + align:start position:0% +like one + + + align:start position:0% +like one +item of production now why are the + + align:start position:0% +item of production now why are the + + + align:start position:0% +item of production now why are the +different units is essentially to + + align:start position:0% +different units is essentially to + + + align:start position:0% +different units is essentially to +separate workers into different lines of + + align:start position:0% +separate workers into different lines of + + + align:start position:0% +separate workers into different lines of +work + + align:start position:0% +work + + + align:start position:0% +work +so what we're going to expect is that + + align:start position:0% +so what we're going to expect is that + + + align:start position:0% +so what we're going to expect is that +workers are going to compare each + + align:start position:0% +workers are going to compare each + + + align:start position:0% +workers are going to compare each +other's + + align:start position:0% +other's + + + align:start position:0% +other's +within unit but not so much across units + + align:start position:0% +within unit but not so much across units + + + align:start position:0% +within unit but not so much across units +because if i make brooms and you make + + align:start position:0% +because if i make brooms and you make + + + align:start position:0% +because if i make brooms and you make +instant sticks that's very different + + align:start position:0% +instant sticks that's very different + + + align:start position:0% +instant sticks that's very different +work in some ways but if you make the + + align:start position:0% +work in some ways but if you make the + + + align:start position:0% +work in some ways but if you make the +exact same thing the natural + + align:start position:0% +exact same thing the natural + + + align:start position:0% +exact same thing the natural +comparison now for workers to compare + + align:start position:0% +comparison now for workers to compare + + + align:start position:0% +comparison now for workers to compare +yourself with another worker + + align:start position:0% +yourself with another worker + + + align:start position:0% +yourself with another worker +all unit members so everybody in a given + + align:start position:0% +all unit members so everybody in a given + + + align:start position:0% +all unit members so everybody in a given +unit makes the exact same product so + + align:start position:0% +unit makes the exact same product so + + + align:start position:0% +unit makes the exact same product so +everybody in unit + + align:start position:0% +everybody in unit + + + align:start position:0% +everybody in unit +one who has like three workers makes + + align:start position:0% +one who has like three workers makes + + + align:start position:0% +one who has like three workers makes +brooms + + align:start position:0% +brooms + + + align:start position:0% +brooms +everybody in unit 2 makes incense sticks + + align:start position:0% +everybody in unit 2 makes incense sticks + + + align:start position:0% +everybody in unit 2 makes incense sticks +and so on + + align:start position:0% +and so on + + + align:start position:0% +and so on +now the key experimental variation in + + align:start position:0% +now the key experimental variation in + + + align:start position:0% +now the key experimental variation in +the in the experiment + + align:start position:0% +the in the experiment + + + align:start position:0% +the in the experiment +is wage dispersion across workers within + + align:start position:0% +is wage dispersion across workers within + + + align:start position:0% +is wage dispersion across workers within +teams + + align:start position:0% +teams + + + align:start position:0% +teams +finally there's uh also um and i'll get + + align:start position:0% +finally there's uh also um and i'll get + + + align:start position:0% +finally there's uh also um and i'll get +back to that at the end production tasks + + align:start position:0% +back to that at the end production tasks + + + align:start position:0% +back to that at the end production tasks +vary in their observability of uh + + align:start position:0% +vary in their observability of uh + + + align:start position:0% +vary in their observability of uh +performance + + align:start position:0% +performance + + + align:start position:0% +performance +so that is to say for some tasks it just + + align:start position:0% +so that is to say for some tasks it just + + + align:start position:0% +so that is to say for some tasks it just +happens to be that it's + + align:start position:0% +happens to be that it's + + + align:start position:0% +happens to be that it's +much easier to understand how productive + + align:start position:0% +much easier to understand how productive + + + align:start position:0% +much easier to understand how productive +your co-worker is than in other + + align:start position:0% +your co-worker is than in other + + + align:start position:0% +your co-worker is than in other +tasks okay so now what is the + + align:start position:0% +tasks okay so now what is the + + + align:start position:0% +tasks okay so now what is the +variation in relative pay so here you + + align:start position:0% +variation in relative pay so here you + + + align:start position:0% +variation in relative pay so here you +see um + + align:start position:0% +see um + + + align:start position:0% +see um +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +people are paid depending on their + + align:start position:0% +people are paid depending on their + + + align:start position:0% +people are paid depending on their +worker rank + + align:start position:0% +worker rank + + + align:start position:0% +worker rank +there's four different regimes of pay in + + align:start position:0% +there's four different regimes of pay in + + + align:start position:0% +there's four different regimes of pay in +the different columns + + align:start position:0% +the different columns + + + align:start position:0% +the different columns +heterogeneous compressed l compressed m + + align:start position:0% +heterogeneous compressed l compressed m + + + align:start position:0% +heterogeneous compressed l compressed m +and compress + + align:start position:0% +and compress + + + align:start position:0% +and compress +h workers are sorted so there's a + + align:start position:0% +h workers are sorted so there's a + + + align:start position:0% +h workers are sorted so there's a +baseline period where workers are worked + + align:start position:0% +baseline period where workers are worked + + + align:start position:0% +baseline period where workers are worked +for a few days + + align:start position:0% +for a few days + + + align:start position:0% +for a few days +and a few days are used to assess their + + align:start position:0% +and a few days are used to assess their + + + align:start position:0% +and a few days are used to assess their +baseline productivity + + align:start position:0% +baseline productivity + + + align:start position:0% +baseline productivity +they're ranked into three tertiles + + align:start position:0% +they're ranked into three tertiles + + + align:start position:0% +they're ranked into three tertiles +so there's like the low productive + + align:start position:0% +so there's like the low productive + + + align:start position:0% +so there's like the low productive +workers medium productivity and high + + align:start position:0% +workers medium productivity and high + + + align:start position:0% +workers medium productivity and high +productivity workers + + align:start position:0% +productivity workers + + + align:start position:0% +productivity workers +they're ranked essentially based on how + + align:start position:0% +they're ranked essentially based on how + + + align:start position:0% +they're ranked essentially based on how +well they did at baseline + + align:start position:0% +well they did at baseline + + + align:start position:0% +well they did at baseline +okay so if you're like really bad to + + align:start position:0% +okay so if you're like really bad to + + + align:start position:0% +okay so if you're like really bad to +start with you would be a low + + align:start position:0% +start with you would be a low + + + align:start position:0% +start with you would be a low +productivity worker if you're like an + + align:start position:0% +productivity worker if you're like an + + + align:start position:0% +productivity worker if you're like an +average worker it would be medium + + align:start position:0% +average worker it would be medium + + + align:start position:0% +average worker it would be medium +productivity + + align:start position:0% +productivity + + + align:start position:0% +productivity +and if you're really like highly + + align:start position:0% +and if you're really like highly + + + align:start position:0% +and if you're really like highly +productive worker you would be + + align:start position:0% +productive worker you would be + + + align:start position:0% +productive worker you would be +classified as + + align:start position:0% +classified as + + + align:start position:0% +classified as +high productivity workers notice that's + + align:start position:0% +high productivity workers notice that's + + + align:start position:0% +high productivity workers notice that's +always done for all of the different + + align:start position:0% +always done for all of the different + + + align:start position:0% +always done for all of the different +treatment groups + + align:start position:0% +treatment groups + + + align:start position:0% +treatment groups +the difference now is across these + + align:start position:0% +the difference now is across these + + + align:start position:0% +the difference now is across these +different + + align:start position:0% +different + + + align:start position:0% +different +regimes how workers are paid in the + + align:start position:0% +regimes how workers are paid in the + + + align:start position:0% +regimes how workers are paid in the +heterogeneous pay essentially there's + + align:start position:0% +heterogeneous pay essentially there's + + + align:start position:0% +heterogeneous pay essentially there's +differences in + + align:start position:0% +differences in + + + align:start position:0% +differences in +um across workers in the sense that like + + align:start position:0% +um across workers in the sense that like + + + align:start position:0% +um across workers in the sense that like +uh the low productivity workers are paid + + align:start position:0% +uh the low productivity workers are paid + + + align:start position:0% +uh the low productivity workers are paid +the low wage the median productivity pay + + align:start position:0% +the low wage the median productivity pay + + + align:start position:0% +the low wage the median productivity pay +workers are paid a medium wage and the + + align:start position:0% +workers are paid a medium wage and the + + + align:start position:0% +workers are paid a medium wage and the +high productivity workers are paid a + + align:start position:0% +high productivity workers are paid a + + + align:start position:0% +high productivity workers are paid a +high wage + + align:start position:0% +high wage + + + align:start position:0% +high wage +as you might expect that's sort of the + + align:start position:0% +as you might expect that's sort of the + + + align:start position:0% +as you might expect that's sort of the +natural thing to do in terms of you want + + align:start position:0% +natural thing to do in terms of you want + + + align:start position:0% +natural thing to do in terms of you want +to reward productivity + + align:start position:0% +to reward productivity + + + align:start position:0% +to reward productivity +the most productive workers you're going + + align:start position:0% +the most productive workers you're going + + + align:start position:0% +the most productive workers you're going +to pay + + align:start position:0% +to pay + + + align:start position:0% +to pay +the most notice that these wage + + align:start position:0% +the most notice that these wage + + + align:start position:0% +the most notice that these wage +differences are modest so even like the + + align:start position:0% +differences are modest so even like the + + + align:start position:0% +differences are modest so even like the +difference between + + align:start position:0% +difference between + + + align:start position:0% +difference between +a w high and w uh low are like uh + + align:start position:0% +a w high and w uh low are like uh + + + align:start position:0% +a w high and w uh low are like uh +uh uh only about like up to 10 + + align:start position:0% +uh uh only about like up to 10 + + + align:start position:0% +uh uh only about like up to 10 +so really these are not huge differences + + align:start position:0% +so really these are not huge differences + + + align:start position:0% +so really these are not huge differences +it's not that the other guy if you are + + align:start position:0% +it's not that the other guy if you are + + + align:start position:0% +it's not that the other guy if you are +like a little productivity worker + + align:start position:0% +like a little productivity worker + + + align:start position:0% +like a little productivity worker +or if you get wlo it's not the other guy + + align:start position:0% +or if you get wlo it's not the other guy + + + align:start position:0% +or if you get wlo it's not the other guy +gets like twice as much it really is + + align:start position:0% +gets like twice as much it really is + + + align:start position:0% +gets like twice as much it really is +like modestly more + + align:start position:0% +like modestly more + + + align:start position:0% +like modestly more +but it is more money that they get now + + align:start position:0% +but it is more money that they get now + + + align:start position:0% +but it is more money that they get now +then + + align:start position:0% +then + + + align:start position:0% +then +if you look at the other three regimes + + align:start position:0% +if you look at the other three regimes + + + align:start position:0% +if you look at the other three regimes +compressed l compressed m compressed age + + align:start position:0% +compressed l compressed m compressed age + + + align:start position:0% +compressed l compressed m compressed age +low productivity so in compressed l + + align:start position:0% +low productivity so in compressed l + + + align:start position:0% +low productivity so in compressed l +everybody gets the low wage and + + align:start position:0% +everybody gets the low wage and + + + align:start position:0% +everybody gets the low wage and +compressed m + + align:start position:0% +compressed m + + + align:start position:0% +compressed m +everybody gets the medium wage and + + align:start position:0% +everybody gets the medium wage and + + + align:start position:0% +everybody gets the medium wage and +compressed age + + align:start position:0% +compressed age + + + align:start position:0% +compressed age +everybody gets the high wage now the + + align:start position:0% +everybody gets the high wage now the + + + align:start position:0% +everybody gets the high wage now the +study now lets the authors compare + + align:start position:0% +study now lets the authors compare + + + align:start position:0% +study now lets the authors compare +the different columns for holding + + align:start position:0% +the different columns for holding + + + align:start position:0% +the different columns for holding +exactly constant baseline productivity + + align:start position:0% +exactly constant baseline productivity + + + align:start position:0% +exactly constant baseline productivity +and wage levels + + align:start position:0% +and wage levels + + + align:start position:0% +and wage levels +that is to say for instance we can + + align:start position:0% +that is to say for instance we can + + + align:start position:0% +that is to say for instance we can +compare the + + align:start position:0% +compare the + + + align:start position:0% +compare the +heterogeneous low the low productivity + + align:start position:0% +heterogeneous low the low productivity + + + align:start position:0% +heterogeneous low the low productivity +workers that happen to be randomized + + align:start position:0% +workers that happen to be randomized + + + align:start position:0% +workers that happen to be randomized +into like the heterogeneous treatments + + align:start position:0% +into like the heterogeneous treatments + + + align:start position:0% +into like the heterogeneous treatments +they receive wlo or uh compare them with + + align:start position:0% +they receive wlo or uh compare them with + + + align:start position:0% +they receive wlo or uh compare them with +like low productivity workers at + + align:start position:0% +like low productivity workers at + + + align:start position:0% +like low productivity workers at +baseline who happen to be randomized + + align:start position:0% +baseline who happen to be randomized + + + align:start position:0% +baseline who happen to be randomized +into a compressed l + + align:start position:0% +into a compressed l + + + align:start position:0% +into a compressed l +so i should have said more clearly + + align:start position:0% +so i should have said more clearly + + + align:start position:0% +so i should have said more clearly +people are randomized into any of these + + align:start position:0% +people are randomized into any of these + + + align:start position:0% +people are randomized into any of these +four groups + + align:start position:0% +four groups + + + align:start position:0% +four groups +and then depending on what your baseline + + align:start position:0% +and then depending on what your baseline + + + align:start position:0% +and then depending on what your baseline +productivity is you get the wages as i + + align:start position:0% +productivity is you get the wages as i + + + align:start position:0% +productivity is you get the wages as i +show here + + align:start position:0% +show here + + + align:start position:0% +show here +in the table so for example if you're + + align:start position:0% +in the table so for example if you're + + + align:start position:0% +in the table so for example if you're +like a low productivity worker you might + + align:start position:0% +like a low productivity worker you might + + + align:start position:0% +like a low productivity worker you might +be + + align:start position:0% +be + + + align:start position:0% +be +randomized into the heterogeneous + + align:start position:0% +randomized into the heterogeneous + + + align:start position:0% +randomized into the heterogeneous +treatment + + align:start position:0% +treatment + + + align:start position:0% +treatment +group you might receive w low or you + + align:start position:0% +group you might receive w low or you + + + align:start position:0% +group you might receive w low or you +might be randomized into the + + align:start position:0% +might be randomized into the + + + align:start position:0% +might be randomized into the +low compressed load treatment + + align:start position:0% +low compressed load treatment + + + align:start position:0% +low compressed load treatment +where you also receive wlo notice that + + align:start position:0% +where you also receive wlo notice that + + + align:start position:0% +where you also receive wlo notice that +your + + align:start position:0% +your + + + align:start position:0% +your +in both cases that worker is a low + + align:start position:0% +in both cases that worker is a low + + + align:start position:0% +in both cases that worker is a low +productivity worker + + align:start position:0% +productivity worker + + + align:start position:0% +productivity worker +uh in both cases the worker receives w + + align:start position:0% +uh in both cases the worker receives w + + + align:start position:0% +uh in both cases the worker receives w +low + + align:start position:0% +low + + + align:start position:0% +low +however what's different here now is + + align:start position:0% +however what's different here now is + + + align:start position:0% +however what's different here now is +that his co-worker his or her i think + + align:start position:0% +that his co-worker his or her i think + + + align:start position:0% +that his co-worker his or her i think +his in this case these are men + + align:start position:0% +his in this case these are men + + + align:start position:0% +his in this case these are men +co-workers are receiving either the same + + align:start position:0% +co-workers are receiving either the same + + + align:start position:0% +co-workers are receiving either the same +which is in compressed l + + align:start position:0% +which is in compressed l + + + align:start position:0% +which is in compressed l +or they receive higher wages uh in the + + align:start position:0% +or they receive higher wages uh in the + + + align:start position:0% +or they receive higher wages uh in the +heterogeneous wage treatment + + align:start position:0% +heterogeneous wage treatment + + + align:start position:0% +heterogeneous wage treatment +right so now we can look at like workers + + align:start position:0% +right so now we can look at like workers + + + align:start position:0% +right so now we can look at like workers +who have the exact same baseline + + align:start position:0% +who have the exact same baseline + + + align:start position:0% +who have the exact same baseline +productivity on average at least + + align:start position:0% +productivity on average at least + + + align:start position:0% +productivity on average at least +and have the exact same wage but what's + + align:start position:0% +and have the exact same wage but what's + + + align:start position:0% +and have the exact same wage but what's +being varied is like how much other + + align:start position:0% +being varied is like how much other + + + align:start position:0% +being varied is like how much other +workers are earning + + align:start position:0% +workers are earning + + + align:start position:0% +workers are earning +we can do this for low productivity + + align:start position:0% +we can do this for low productivity + + + align:start position:0% +we can do this for low productivity +workers we can also do it for medium + + align:start position:0% +workers we can also do it for medium + + + align:start position:0% +workers we can also do it for medium +productivity workers or + + align:start position:0% +productivity workers or + + + align:start position:0% +productivity workers or +also for high productivity workers i + + align:start position:0% +also for high productivity workers i + + + align:start position:0% +also for high productivity workers i +skipped the medium productivity worker + + align:start position:0% +skipped the medium productivity worker + + + align:start position:0% +skipped the medium productivity worker +but that's exactly the same + + align:start position:0% +but that's exactly the same + + + align:start position:0% +but that's exactly the same +for high productivity workers we can + + align:start position:0% +for high productivity workers we can + + + align:start position:0% +for high productivity workers we can +look at the workers who + + align:start position:0% +look at the workers who + + + align:start position:0% +look at the workers who +have been randomized into the + + align:start position:0% + + + + align:start position:0% + +heterogeneous treatment uh group or + + align:start position:0% +heterogeneous treatment uh group or + + + align:start position:0% +heterogeneous treatment uh group or +hedonist worker group + + align:start position:0% +hedonist worker group + + + align:start position:0% +hedonist worker group +uh sorry heterogeneous wage group where + + align:start position:0% +uh sorry heterogeneous wage group where + + + align:start position:0% +uh sorry heterogeneous wage group where +um the worker gets a wh but everybody + + align:start position:0% +um the worker gets a wh but everybody + + + align:start position:0% +um the worker gets a wh but everybody +else gets like a lower wage or we can + + align:start position:0% +else gets like a lower wage or we can + + + align:start position:0% +else gets like a lower wage or we can +compare that to + + align:start position:0% +compare that to + + + align:start position:0% +compare that to +a compressed age where everybody gets + + align:start position:0% +a compressed age where everybody gets + + + align:start position:0% +a compressed age where everybody gets +wh in that group + + align:start position:0% + + + + align:start position:0% + +okay so now what do you what do the + + align:start position:0% +okay so now what do you what do the + + + align:start position:0% +okay so now what do you what do the +authors find let's start with the + + align:start position:0% +authors find let's start with the + + + align:start position:0% +authors find let's start with the +low productivity workers at baseline + + align:start position:0% +low productivity workers at baseline + + + align:start position:0% +low productivity workers at baseline +remember the clean comparison here is + + align:start position:0% +remember the clean comparison here is + + + align:start position:0% +remember the clean comparison here is +between + + align:start position:0% +between + + + align:start position:0% +between +pay disparity this is the heterogeneous + + align:start position:0% +pay disparity this is the heterogeneous + + + align:start position:0% +pay disparity this is the heterogeneous +group pay disparity and compressed l + + align:start position:0% +group pay disparity and compressed l + + + align:start position:0% +group pay disparity and compressed l +which is like the group where everybody + + align:start position:0% +which is like the group where everybody + + + align:start position:0% +which is like the group where everybody +has paid + + align:start position:0% +has paid + + + align:start position:0% +has paid +the same now what the authors find and + + align:start position:0% +the same now what the authors find and + + + align:start position:0% +the same now what the authors find and +you see this in the graph + + align:start position:0% +you see this in the graph + + + align:start position:0% +you see this in the graph +fairly nicely which is like the + + align:start position:0% +fairly nicely which is like the + + + align:start position:0% +fairly nicely which is like the +productivities are like the red line and + + align:start position:0% +productivities are like the red line and + + + align:start position:0% +productivities are like the red line and +the blue line the productivity on the + + align:start position:0% +the blue line the productivity on the + + + align:start position:0% +the blue line the productivity on the +left side this is before the treatment + + align:start position:0% +left side this is before the treatment + + + align:start position:0% +left side this is before the treatment +starts + + align:start position:0% +starts + + + align:start position:0% +starts +for about over 10 days the productivity + + align:start position:0% +for about over 10 days the productivity + + + align:start position:0% +for about over 10 days the productivity +looks pretty much + + align:start position:0% +looks pretty much + + + align:start position:0% +looks pretty much +the same but then when you go to the + + align:start position:0% +the same but then when you go to the + + + align:start position:0% +the same but then when you go to the +right side of the graph + + align:start position:0% +right side of the graph + + + align:start position:0% +right side of the graph +not immediately but after a few days + + align:start position:0% +not immediately but after a few days + + + align:start position:0% +not immediately but after a few days +there seem to be + + align:start position:0% +there seem to be + + + align:start position:0% +there seem to be +a gap or a gap emerges between the red + + align:start position:0% +a gap or a gap emerges between the red + + + align:start position:0% +a gap or a gap emerges between the red +line and the blue line which is exactly + + align:start position:0% +line and the blue line which is exactly + + + align:start position:0% +line and the blue line which is exactly +the gap as you would expect + + align:start position:0% +the gap as you would expect + + + align:start position:0% +the gap as you would expect +if pay disperse the disparity + + align:start position:0% +if pay disperse the disparity + + + align:start position:0% +if pay disperse the disparity +makes workers less productive which is + + align:start position:0% +makes workers less productive which is + + + align:start position:0% +makes workers less productive which is +to say + + align:start position:0% +to say + + + align:start position:0% +to say +they're workers who receive a low wage + + align:start position:0% +they're workers who receive a low wage + + + align:start position:0% +they're workers who receive a low wage +but others in their group are receiving + + align:start position:0% +but others in their group are receiving + + + align:start position:0% +but others in their group are receiving +higher wages are becoming + + align:start position:0% +higher wages are becoming + + + align:start position:0% +higher wages are becoming +less productive compared to workers + + align:start position:0% +less productive compared to workers + + + align:start position:0% +less productive compared to workers +that receive a low wage where others + + align:start position:0% +that receive a low wage where others + + + align:start position:0% +that receive a low wage where others +have the exact same + + align:start position:0% +have the exact same + + + align:start position:0% +have the exact same +productivity and you see this also in + + align:start position:0% +productivity and you see this also in + + + align:start position:0% +productivity and you see this also in +the regression tables you see about a 22 + + align:start position:0% +the regression tables you see about a 22 + + + align:start position:0% +the regression tables you see about a 22 +percent + + align:start position:0% +percent + + + align:start position:0% +percent +reduction in mean outputs and a 9 + + align:start position:0% +reduction in mean outputs and a 9 + + + align:start position:0% +reduction in mean outputs and a 9 +reduction in in earnings which are + + align:start position:0% +reduction in in earnings which are + + + align:start position:0% +reduction in in earnings which are +pretty large effects so these are like + + align:start position:0% +pretty large effects so these are like + + + align:start position:0% +pretty large effects so these are like +large effects compared to like other + + align:start position:0% +large effects compared to like other + + + align:start position:0% +large effects compared to like other +interventions that people have + + align:start position:0% +interventions that people have + + + align:start position:0% +interventions that people have +tried interesting and you see a little + + align:start position:0% +tried interesting and you see a little + + + align:start position:0% +tried interesting and you see a little +bit like um + + align:start position:0% +bit like um + + + align:start position:0% +bit like um +well the treatment effect when you look + + align:start position:0% +well the treatment effect when you look + + + align:start position:0% +well the treatment effect when you look +at the graph initially looks not + + align:start position:0% +at the graph initially looks not + + + align:start position:0% +at the graph initially looks not +particularly large + + align:start position:0% +particularly large + + + align:start position:0% +particularly large +if anything it's this might not even be + + align:start position:0% +if anything it's this might not even be + + + align:start position:0% +if anything it's this might not even be +there after like a few days + + align:start position:0% +there after like a few days + + + align:start position:0% +there after like a few days +that treatment effect increases over + + align:start position:0% +that treatment effect increases over + + + align:start position:0% +that treatment effect increases over +time it becomes larger so + + align:start position:0% +time it becomes larger so + + + align:start position:0% +time it becomes larger so +over time people become less and less + + align:start position:0% +over time people become less and less + + + align:start position:0% +over time people become less and less +productive compared to the + + align:start position:0% +productive compared to the + + + align:start position:0% +productive compared to the +compressed wage treatment interestingly + + align:start position:0% +compressed wage treatment interestingly + + + align:start position:0% +compressed wage treatment interestingly +we find or the authors find + + align:start position:0% +we find or the authors find + + + align:start position:0% +we find or the authors find +similar effects for high rank high + + align:start position:0% +similar effects for high rank high + + + align:start position:0% +similar effects for high rank high +productivity workers + + align:start position:0% +productivity workers + + + align:start position:0% +productivity workers +so notice that these are now workers who + + align:start position:0% +so notice that these are now workers who + + + align:start position:0% +so notice that these are now workers who +either who are + + align:start position:0% +either who are + + + align:start position:0% +either who are +high productivity workers they receive + + align:start position:0% +high productivity workers they receive + + + align:start position:0% +high productivity workers they receive +the same wage in the pay disparity + + align:start position:0% +the same wage in the pay disparity + + + align:start position:0% +the same wage in the pay disparity +treatment and the compressed age + + align:start position:0% +treatment and the compressed age + + + align:start position:0% +treatment and the compressed age +treatment + + align:start position:0% +treatment + + + align:start position:0% +treatment +that have the same wage in one case they + + align:start position:0% +that have the same wage in one case they + + + align:start position:0% +that have the same wage in one case they +are + + align:start position:0% +are + + + align:start position:0% +are +paid exactly the same in the other case + + align:start position:0% +paid exactly the same in the other case + + + align:start position:0% +paid exactly the same in the other case +they are paid + + align:start position:0% +they are paid + + + align:start position:0% +they are paid +more compared to their co-workers and + + align:start position:0% +more compared to their co-workers and + + + align:start position:0% +more compared to their co-workers and +what happens to me or what seems to be + + align:start position:0% +what happens to me or what seems to be + + + align:start position:0% +what happens to me or what seems to be +the case is that + + align:start position:0% +the case is that + + + align:start position:0% +the case is that +the compressed um high-pay workers + + align:start position:0% +the compressed um high-pay workers + + + align:start position:0% +the compressed um high-pay workers +they're in fact + + align:start position:0% +they're in fact + + + align:start position:0% +they're in fact +more productive compared to others you + + align:start position:0% +more productive compared to others you + + + align:start position:0% +more productive compared to others you +might have expected in some ways like if + + align:start position:0% +might have expected in some ways like if + + + align:start position:0% +might have expected in some ways like if +one guy + + align:start position:0% +one guy + + + align:start position:0% +one guy +gets paid high payment and others get + + align:start position:0% +gets paid high payment and others get + + + align:start position:0% +gets paid high payment and others get +paid less that makes the high pay worker + + align:start position:0% +paid less that makes the high pay worker + + + align:start position:0% +paid less that makes the high pay worker +more productive because maybe he feels + + align:start position:0% +more productive because maybe he feels + + + align:start position:0% +more productive because maybe he feels +good about himself that he's the high + + align:start position:0% +good about himself that he's the high + + + align:start position:0% +good about himself that he's the high +pay workers or maybe he feels like you + + align:start position:0% +pay workers or maybe he feels like you + + + align:start position:0% +pay workers or maybe he feels like you +prove himself or the like + + align:start position:0% +prove himself or the like + + + align:start position:0% +prove himself or the like +but instead what seems to be the case + + align:start position:0% +but instead what seems to be the case + + + align:start position:0% +but instead what seems to be the case +the group that works um + + align:start position:0% +the group that works um + + + align:start position:0% +the group that works um +in his team does not work well together + + align:start position:0% +in his team does not work well together + + + align:start position:0% +in his team does not work well together +or they just + + align:start position:0% +or they just + + + align:start position:0% +or they just +becomes uncomfortable to work with like + + align:start position:0% +becomes uncomfortable to work with like + + + align:start position:0% +becomes uncomfortable to work with like +somebody else who is like really mad at + + align:start position:0% +somebody else who is like really mad at + + + align:start position:0% +somebody else who is like really mad at +you for earning more + + align:start position:0% +you for earning more + + + align:start position:0% +you for earning more +than they do and so now the high + + align:start position:0% +than they do and so now the high + + + align:start position:0% +than they do and so now the high +pay workers in the compressed treatment + + align:start position:0% +pay workers in the compressed treatment + + + align:start position:0% +pay workers in the compressed treatment +in fact earn more + + align:start position:0% +in fact earn more + + + align:start position:0% +in fact earn more +or produce more than the uh high pay + + align:start position:0% +or produce more than the uh high pay + + + align:start position:0% +or produce more than the uh high pay +workers + + align:start position:0% +workers + + + align:start position:0% +workers +in the pay disparity treatment so that + + align:start position:0% +in the pay disparity treatment so that + + + align:start position:0% +in the pay disparity treatment so that +is to say the + + align:start position:0% +is to say the + + + align:start position:0% +is to say the +pay disparity or pain equality + + align:start position:0% +pay disparity or pain equality + + + align:start position:0% +pay disparity or pain equality +does not only reduce uh workers + + align:start position:0% +does not only reduce uh workers + + + align:start position:0% +does not only reduce uh workers +productivity for the low pay workers so + + align:start position:0% +productivity for the low pay workers so + + + align:start position:0% +productivity for the low pay workers so +not only the people who + + align:start position:0% +not only the people who + + + align:start position:0% +not only the people who +work the workers who are earning less + + align:start position:0% +work the workers who are earning less + + + align:start position:0% +work the workers who are earning less +compared to their coworkers + + align:start position:0% +compared to their coworkers + + + align:start position:0% +compared to their coworkers +and that's in some sense to be expected + + align:start position:0% +and that's in some sense to be expected + + + align:start position:0% +and that's in some sense to be expected +you might just be mad that everybody + + align:start position:0% +you might just be mad that everybody + + + align:start position:0% +you might just be mad that everybody +else or other people in your group + + align:start position:0% +else or other people in your group + + + align:start position:0% +else or other people in your group +are earning more then you might be + + align:start position:0% +are earning more then you might be + + + align:start position:0% +are earning more then you might be +unhappy and mad about that and just then + + align:start position:0% +unhappy and mad about that and just then + + + align:start position:0% +unhappy and mad about that and just then +produce + + align:start position:0% +produce + + + align:start position:0% +produce +less instead it seems to be the case + + align:start position:0% +less instead it seems to be the case + + + align:start position:0% +less instead it seems to be the case +even the high productivity workers the + + align:start position:0% +even the high productivity workers the + + + align:start position:0% +even the high productivity workers the +workers who are + + align:start position:0% +workers who are + + + align:start position:0% +workers who are +earn more than others in their group are + + align:start position:0% +earn more than others in their group are + + + align:start position:0% +earn more than others in their group are +producing + + align:start position:0% +producing + + + align:start position:0% +producing +less compared to the control group where + + align:start position:0% +less compared to the control group where + + + align:start position:0% +less compared to the control group where +everybody earns the + + align:start position:0% +everybody earns the + + + align:start position:0% +everybody earns the +same so what do we learn from that well + + align:start position:0% +same so what do we learn from that well + + + align:start position:0% +same so what do we learn from that well +pay disparity lowers work + + align:start position:0% +pay disparity lowers work + + + align:start position:0% +pay disparity lowers work +performance for all team members um + + align:start position:0% +performance for all team members um + + + align:start position:0% +performance for all team members um +and so the interpretation of that is + + align:start position:0% +and so the interpretation of that is + + + align:start position:0% +and so the interpretation of that is +that that pay uh disparity + + align:start position:0% +that that pay uh disparity + + + align:start position:0% +that that pay uh disparity +undermines workers ability to cooperate + + align:start position:0% +undermines workers ability to cooperate + + + align:start position:0% +undermines workers ability to cooperate +cooperate in their own + + align:start position:0% +cooperate in their own + + + align:start position:0% +cooperate in their own +self-interests um the the paper has some + + align:start position:0% +self-interests um the the paper has some + + + align:start position:0% +self-interests um the the paper has some +additional evidence with some + + align:start position:0% +additional evidence with some + + + align:start position:0% +additional evidence with some +cooperative tasks + + align:start position:0% +cooperative tasks + + + align:start position:0% +cooperative tasks +where essentially workers are worse at + + align:start position:0% +where essentially workers are worse at + + + align:start position:0% +where essentially workers are worse at +cooperating with each other + + align:start position:0% +cooperating with each other + + + align:start position:0% +cooperating with each other +it seems to really be that workers are + + align:start position:0% +it seems to really be that workers are + + + align:start position:0% +it seems to really be that workers are +not happy + + align:start position:0% +not happy + + + align:start position:0% +not happy +to work in the same place with somebody + + align:start position:0% +to work in the same place with somebody + + + align:start position:0% +to work in the same place with somebody +else who + + align:start position:0% +else who + + + align:start position:0% +else who +earns less importantly the perceived + + align:start position:0% +earns less importantly the perceived + + + align:start position:0% +earns less importantly the perceived +justification + + align:start position:0% +justification + + + align:start position:0% +justification +is essential in mediating these effects + + align:start position:0% +is essential in mediating these effects + + + align:start position:0% +is essential in mediating these effects +that is to say i told you previously + + align:start position:0% +that is to say i told you previously + + + align:start position:0% +that is to say i told you previously +that for some tasks it was easier to + + align:start position:0% +that for some tasks it was easier to + + + align:start position:0% +that for some tasks it was easier to +see who's more productive than others + + align:start position:0% +see who's more productive than others + + + align:start position:0% +see who's more productive than others +especially at baseline just because in + + align:start position:0% +especially at baseline just because in + + + align:start position:0% +especially at baseline just because in +the task you know the differences across + + align:start position:0% +the task you know the differences across + + + align:start position:0% +the task you know the differences across +highly and less highly productive or + + align:start position:0% +highly and less highly productive or + + + align:start position:0% +highly and less highly productive or +lower high and low productivity workers + + align:start position:0% +lower high and low productivity workers + + + align:start position:0% +lower high and low productivity workers +was just wider and it's just easy to see + + align:start position:0% +was just wider and it's just easy to see + + + align:start position:0% +was just wider and it's just easy to see +that + + align:start position:0% +that + + + align:start position:0% +that +frank is really bad at this and somebody + + align:start position:0% +frank is really bad at this and somebody + + + align:start position:0% +frank is really bad at this and somebody +else is really good and for some tasks + + align:start position:0% +else is really good and for some tasks + + + align:start position:0% +else is really good and for some tasks +it's really easy to see that + + align:start position:0% +it's really easy to see that + + + align:start position:0% +it's really easy to see that +for others not so if it's really easy if + + align:start position:0% +for others not so if it's really easy if + + + align:start position:0% +for others not so if it's really easy if +there's a perceived justification + + align:start position:0% +there's a perceived justification + + + align:start position:0% +there's a perceived justification +for workers if workers sort of thought + + align:start position:0% +for workers if workers sort of thought + + + align:start position:0% +for workers if workers sort of thought +okay it's really easy to see who is more + + align:start position:0% +okay it's really easy to see who is more + + + align:start position:0% +okay it's really easy to see who is more +productive than others + + align:start position:0% +productive than others + + + align:start position:0% +productive than others +the effects are much weaker than when + + align:start position:0% +the effects are much weaker than when + + + align:start position:0% +the effects are much weaker than when +there is no perceived justification + + align:start position:0% +there is no perceived justification + + + align:start position:0% +there is no perceived justification +that is to say workers themselves are + + align:start position:0% +that is to say workers themselves are + + + align:start position:0% +that is to say workers themselves are +saying like if i'm saying like look + + align:start position:0% +saying like if i'm saying like look + + + align:start position:0% +saying like if i'm saying like look +there's this other worker who's really + + align:start position:0% +there's this other worker who's really + + + align:start position:0% +there's this other worker who's really +productive + + align:start position:0% +productive + + + align:start position:0% +productive +and if i'm sort of saying like hey look + + align:start position:0% +and if i'm sort of saying like hey look + + + align:start position:0% +and if i'm sort of saying like hey look +this is really obvious that they're more + + align:start position:0% +this is really obvious that they're more + + + align:start position:0% +this is really obvious that they're more +productive than i am + + align:start position:0% +productive than i am + + + align:start position:0% +productive than i am +it's only fair that they're earning more + + align:start position:0% +it's only fair that they're earning more + + + align:start position:0% +it's only fair that they're earning more +then + + align:start position:0% +then + + + align:start position:0% +then +these effects are much damp and there's + + align:start position:0% +these effects are much damp and there's + + + align:start position:0% +these effects are much damp and there's +much less in fact it's it's accepted + + align:start position:0% +much less in fact it's it's accepted + + + align:start position:0% +much less in fact it's it's accepted +and there's much less of a productivity + + align:start position:0% +and there's much less of a productivity + + + align:start position:0% +and there's much less of a productivity +effect if any + + align:start position:0% +effect if any + + + align:start position:0% +effect if any +uh if there's pay inequality however if + + align:start position:0% +uh if there's pay inequality however if + + + align:start position:0% +uh if there's pay inequality however if +it seems to be the case that we're kind + + align:start position:0% +it seems to be the case that we're kind + + + align:start position:0% +it seems to be the case that we're kind +of like producing the same thing + + align:start position:0% +of like producing the same thing + + + align:start position:0% +of like producing the same thing +if um and we're like similar sorry we're + + align:start position:0% +if um and we're like similar sorry we're + + + align:start position:0% +if um and we're like similar sorry we're +producing the same thing and we're + + align:start position:0% +producing the same thing and we're + + + align:start position:0% +producing the same thing and we're +equally good at it or approximately + + align:start position:0% +equally good at it or approximately + + + align:start position:0% +equally good at it or approximately +equally good + + align:start position:0% +equally good + + + align:start position:0% +equally good +and one person is paid more than i am + + align:start position:0% +and one person is paid more than i am + + + align:start position:0% +and one person is paid more than i am +for no good reason + + align:start position:0% +for no good reason + + + align:start position:0% +for no good reason +so it appears then workers are really + + align:start position:0% +so it appears then workers are really + + + align:start position:0% +so it appears then workers are really +not happy about that + + align:start position:0% +not happy about that + + + align:start position:0% +not happy about that +and work performance in particular + + align:start position:0% +and work performance in particular + + + align:start position:0% +and work performance in particular +output + + align:start position:0% +output + + + align:start position:0% +output +falls so what are the implications well + + align:start position:0% +falls so what are the implications well + + + align:start position:0% +falls so what are the implications well +this evidence sort of suggests that wage + + align:start position:0% +this evidence sort of suggests that wage + + + align:start position:0% +this evidence sort of suggests that wage +compression um + + align:start position:0% +compression um + + + align:start position:0% +compression um +may be more likely in some settings than + + align:start position:0% +may be more likely in some settings than + + + align:start position:0% +may be more likely in some settings than +in others right that's to say like + + align:start position:0% +in others right that's to say like + + + align:start position:0% +in others right that's to say like +if it's easy to justify if the + + align:start position:0% +if it's easy to justify if the + + + align:start position:0% +if it's easy to justify if the +production function or like the + + align:start position:0% +production function or like the + + + align:start position:0% +production function or like the +production process is such that all + + align:start position:0% +production process is such that all + + + align:start position:0% +production process is such that all +aspects of the production and the output + + align:start position:0% +aspects of the production and the output + + + align:start position:0% +aspects of the production and the output +or the performance are easy measurable + + align:start position:0% +or the performance are easy measurable + + + align:start position:0% +or the performance are easy measurable +measurable and observable for workers + + align:start position:0% +measurable and observable for workers + + + align:start position:0% +measurable and observable for workers +then you know workers might say + + align:start position:0% +then you know workers might say + + + align:start position:0% +then you know workers might say +it's okay if some workers are earning + + align:start position:0% +it's okay if some workers are earning + + + align:start position:0% +it's okay if some workers are earning +more than others + + align:start position:0% +more than others + + + align:start position:0% +more than others +however if that's not the case if + + align:start position:0% +however if that's not the case if + + + align:start position:0% +however if that's not the case if +there's a bunch of stuff in the work + + align:start position:0% +there's a bunch of stuff in the work + + + align:start position:0% +there's a bunch of stuff in the work +process that's really not observed maybe + + align:start position:0% +process that's really not observed maybe + + + align:start position:0% +process that's really not observed maybe +it's verbal or maybe it's just really + + align:start position:0% +it's verbal or maybe it's just really + + + align:start position:0% +it's verbal or maybe it's just really +hard to justify or hard to sort of + + align:start position:0% +hard to justify or hard to sort of + + + align:start position:0% +hard to justify or hard to sort of +assess in some + + align:start position:0% +assess in some + + + align:start position:0% +assess in some +tangible way then you know workers might + + align:start position:0% +tangible way then you know workers might + + + align:start position:0% +tangible way then you know workers might +be really unhappy + + align:start position:0% +be really unhappy + + + align:start position:0% +be really unhappy +and that might lead to wage compression + + align:start position:0% +and that might lead to wage compression + + + align:start position:0% +and that might lead to wage compression +because the employer might anticipate + + align:start position:0% +because the employer might anticipate + + + align:start position:0% +because the employer might anticipate +um that so overall that sort of says + + align:start position:0% +um that so overall that sort of says + + + align:start position:0% +um that so overall that sort of says +that like + + align:start position:0% +that like + + + align:start position:0% +that like +um relative comparisons matter quite a + + align:start position:0% +um relative comparisons matter quite a + + + align:start position:0% +um relative comparisons matter quite a +bit + + align:start position:0% +bit + + + align:start position:0% +bit +fairness matters quite a bit and what's + + align:start position:0% +fairness matters quite a bit and what's + + + align:start position:0% +fairness matters quite a bit and what's +really key for an employer or anybody + + align:start position:0% +really key for an employer or anybody + + + align:start position:0% +really key for an employer or anybody +who sets incentives + + align:start position:0% +who sets incentives + + + align:start position:0% +who sets incentives +is to take into account these fairness + + align:start position:0% +is to take into account these fairness + + + align:start position:0% +is to take into account these fairness +consideration + + align:start position:0% +consideration + + + align:start position:0% +consideration +rations and one wants to really + + align:start position:0% +rations and one wants to really + + + align:start position:0% +rations and one wants to really +understand what is fair and what is not + + align:start position:0% +understand what is fair and what is not + + + align:start position:0% +understand what is fair and what is not +and upsetting workers by violating these + + align:start position:0% +and upsetting workers by violating these + + + align:start position:0% +and upsetting workers by violating these +fairness considerations or norms + + align:start position:0% +fairness considerations or norms + + + align:start position:0% +fairness considerations or norms +might be really really costly for an + + align:start position:0% +might be really really costly for an + + + align:start position:0% +might be really really costly for an +employer + + align:start position:0% + + + + align:start position:0% + +so the good news here is that like if + + align:start position:0% +so the good news here is that like if + + + align:start position:0% +so the good news here is that like if +one understands that well you know one + + align:start position:0% +one understands that well you know one + + + align:start position:0% +one understands that well you know one +can really sort of produce + + align:start position:0% +can really sort of produce + + + align:start position:0% +can really sort of produce +increase productivity quite a bit and in + + align:start position:0% +increase productivity quite a bit and in + + + align:start position:0% +increase productivity quite a bit and in +some cases + + align:start position:0% +some cases + + + align:start position:0% +some cases +wage inequality is actually fine one + + align:start position:0% +wage inequality is actually fine one + + + align:start position:0% +wage inequality is actually fine one +just has to be careful in figuring out + + align:start position:0% +just has to be careful in figuring out + + + align:start position:0% +just has to be careful in figuring out +when exactly is that the case + + align:start position:0% +when exactly is that the case + + + align:start position:0% +when exactly is that the case +okay as i said there's a very nice paper + + align:start position:0% +okay as i said there's a very nice paper + + + align:start position:0% +okay as i said there's a very nice paper +by + + align:start position:0% +by + + + align:start position:0% +by +jonah stewart on ethnic divisions and + + align:start position:0% +jonah stewart on ethnic divisions and + + + align:start position:0% +jonah stewart on ethnic divisions and +production and firms + + align:start position:0% +production and firms + + + align:start position:0% +production and firms +we're going to talk about that in + + align:start position:0% +we're going to talk about that in + + + align:start position:0% +we're going to talk about that in +recitation + + align:start position:0% + + + + align:start position:0% + +okay the second part of this lecture + + align:start position:0% +okay the second part of this lecture + + + align:start position:0% +okay the second part of this lecture +we'll talk about + + align:start position:0% +we'll talk about + + + align:start position:0% +we'll talk about +policies to increase pro-sociality + + align:start position:0% +policies to increase pro-sociality + + + align:start position:0% +policies to increase pro-sociality +and so uh the first of these papers is a + + align:start position:0% +and so uh the first of these papers is a + + + align:start position:0% +and so uh the first of these papers is a +very nice recent paper by gautam rao + + align:start position:0% +very nice recent paper by gautam rao + + + align:start position:0% +very nice recent paper by gautam rao +that looks at the question are social + + align:start position:0% +that looks at the question are social + + + align:start position:0% +that looks at the question are social +preferences malleable + + align:start position:0% +preferences malleable + + + align:start position:0% +preferences malleable +like what are the origins of social + + align:start position:0% +like what are the origins of social + + + align:start position:0% +like what are the origins of social +preferences why is it that some people + + align:start position:0% +preferences why is it that some people + + + align:start position:0% +preferences why is it that some people +appear nicer + + align:start position:0% +appear nicer + + + align:start position:0% +appear nicer +than others and then you know once we + + align:start position:0% +than others and then you know once we + + + align:start position:0% +than others and then you know once we +understand that perhaps we can also + + align:start position:0% +understand that perhaps we can also + + + align:start position:0% +understand that perhaps we can also +understand what policies of anything + + align:start position:0% +understand what policies of anything + + + align:start position:0% +understand what policies of anything +anything can affect social preferences + + align:start position:0% + + + + align:start position:0% + +the main question that this paper asks + + align:start position:0% +the main question that this paper asks + + + align:start position:0% +the main question that this paper asks +is how does being mixed with poor + + align:start position:0% +is how does being mixed with poor + + + align:start position:0% +is how does being mixed with poor +student in school affect the social + + align:start position:0% +student in school affect the social + + + align:start position:0% +student in school affect the social +preferences of + + align:start position:0% +preferences of + + + align:start position:0% +preferences of +rich students now in a lot of + + align:start position:0% +rich students now in a lot of + + + align:start position:0% +rich students now in a lot of +kind of policies where poor students are + + align:start position:0% +kind of policies where poor students are + + + align:start position:0% +kind of policies where poor students are +mixed with rich students + + align:start position:0% +mixed with rich students + + + align:start position:0% +mixed with rich students +you might ask the question how does it + + align:start position:0% +you might ask the question how does it + + + align:start position:0% +you might ask the question how does it +affect the poor student if a poor + + align:start position:0% +affect the poor student if a poor + + + align:start position:0% +affect the poor student if a poor +student for whatever reason + + align:start position:0% +student for whatever reason + + + align:start position:0% +student for whatever reason +would not be able to afford like a rich + + align:start position:0% +would not be able to afford like a rich + + + align:start position:0% +would not be able to afford like a rich +school or a rich student school + + align:start position:0% +school or a rich student school + + + align:start position:0% +school or a rich student school +and you sort of allow them by giving + + align:start position:0% +and you sort of allow them by giving + + + align:start position:0% +and you sort of allow them by giving +them scholarships or other policies + + align:start position:0% +them scholarships or other policies + + + align:start position:0% +them scholarships or other policies +uh uh often the question that people ask + + align:start position:0% +uh uh often the question that people ask + + + align:start position:0% +uh uh often the question that people ask +is like what are the benefits + + align:start position:0% +is like what are the benefits + + + align:start position:0% +is like what are the benefits +of doing that is this a poor student uh + + align:start position:0% +of doing that is this a poor student uh + + + align:start position:0% +of doing that is this a poor student uh +you know doing better in school or do + + align:start position:0% +you know doing better in school or do + + + align:start position:0% +you know doing better in school or do +they have different types of friends + + align:start position:0% +they have different types of friends + + + align:start position:0% +they have different types of friends +different networks and does that lead to + + align:start position:0% +different networks and does that lead to + + + align:start position:0% +different networks and does that lead to +better jobs and so on and so forth + + align:start position:0% +better jobs and so on and so forth + + + align:start position:0% +better jobs and so on and so forth +this question this paper asked a + + align:start position:0% +this question this paper asked a + + + align:start position:0% +this question this paper asked a +different question and asked the + + align:start position:0% +different question and asked the + + + align:start position:0% +different question and asked the +question about + + align:start position:0% +question about + + + align:start position:0% +question about +what is the effect of rich students if + + align:start position:0% +what is the effect of rich students if + + + align:start position:0% +what is the effect of rich students if +they randomly or quasi-randomly are + + align:start position:0% +they randomly or quasi-randomly are + + + align:start position:0% +they randomly or quasi-randomly are +exposed to + + align:start position:0% +exposed to + + + align:start position:0% +exposed to +uh being in class with additional or + + align:start position:0% +uh being in class with additional or + + + align:start position:0% +uh being in class with additional or +some more poor students um the paper + + align:start position:0% +some more poor students um the paper + + + align:start position:0% +some more poor students um the paper +exploits a policy change that um + + align:start position:0% +exploits a policy change that um + + + align:start position:0% +exploits a policy change that um +introduced an admissions quota of 20 for + + align:start position:0% +introduced an admissions quota of 20 for + + + align:start position:0% +introduced an admissions quota of 20 for +poor students in primary schools + + align:start position:0% +poor students in primary schools + + + align:start position:0% +poor students in primary schools +in in delhi delhi these are like rich + + align:start position:0% +in in delhi delhi these are like rich + + + align:start position:0% +in in delhi delhi these are like rich +private um primary schools the paper + + align:start position:0% +private um primary schools the paper + + + align:start position:0% +private um primary schools the paper +looks at two sources of variation + + align:start position:0% +looks at two sources of variation + + + align:start position:0% +looks at two sources of variation +there's variation across classrooms that + + align:start position:0% +there's variation across classrooms that + + + align:start position:0% +there's variation across classrooms that +allows the author to look at the overall + + align:start position:0% +allows the author to look at the overall + + + align:start position:0% +allows the author to look at the overall +effects so you can look at like + + align:start position:0% +effects so you can look at like + + + align:start position:0% +effects so you can look at like +within schools there's going to be like + + align:start position:0% +within schools there's going to be like + + + align:start position:0% +within schools there's going to be like +treated um uh + + align:start position:0% +treated um uh + + + align:start position:0% +treated um uh +uh uh uncontrolled courts because the + + align:start position:0% +uh uh uncontrolled courts because the + + + align:start position:0% +uh uh uncontrolled courts because the +policy was introduced + + align:start position:0% +policy was introduced + + + align:start position:0% +policy was introduced +uh at some point so for um some students + + align:start position:0% +uh at some point so for um some students + + + align:start position:0% +uh at some point so for um some students +uh uh they enjoyed the benefit of being + + align:start position:0% +uh uh they enjoyed the benefit of being + + + align:start position:0% +uh uh they enjoyed the benefit of being +in class with + + align:start position:0% +in class with + + + align:start position:0% +in class with +with poor students or the costs we'll + + align:start position:0% +with poor students or the costs we'll + + + align:start position:0% +with poor students or the costs we'll +see about that + + align:start position:0% +see about that + + + align:start position:0% +see about that +and for other schools they're already + + align:start position:0% +and for other schools they're already + + + align:start position:0% +and for other schools they're already +too far advanced they were like + + align:start position:0% +too far advanced they were like + + + align:start position:0% +too far advanced they were like +essentially before the pod they went to + + align:start position:0% +essentially before the pod they went to + + + align:start position:0% +essentially before the pod they went to +school before the policy was enacted + + align:start position:0% +school before the policy was enacted + + + align:start position:0% +school before the policy was enacted +and therefore um they were not exposed + + align:start position:0% +and therefore um they were not exposed + + + align:start position:0% +and therefore um they were not exposed +to having poor + + align:start position:0% +to having poor + + + align:start position:0% +to having poor +uh students in in school for for these + + align:start position:0% +uh students in in school for for these + + + align:start position:0% +uh students in in school for for these +treated schools there's essentially + + align:start position:0% +treated schools there's essentially + + + align:start position:0% +treated schools there's essentially +variation within school across cohorts + + align:start position:0% +variation within school across cohorts + + + align:start position:0% +variation within school across cohorts +um that we can look at look at um + + align:start position:0% +um that we can look at look at um + + + align:start position:0% +um that we can look at look at um +second within cohorts we can look at + + align:start position:0% +second within cohorts we can look at + + + align:start position:0% +second within cohorts we can look at +treated and uh + + align:start position:0% +treated and uh + + + align:start position:0% +treated and uh +control schools so some schools were + + align:start position:0% +control schools so some schools were + + + align:start position:0% +control schools so some schools were +getting + + align:start position:0% +getting + + + align:start position:0% +getting +additional poor kids and others did not + + align:start position:0% +additional poor kids and others did not + + + align:start position:0% +additional poor kids and others did not +i'll tell you about this in a second + + align:start position:0% +i'll tell you about this in a second + + + align:start position:0% +i'll tell you about this in a second +and then there's variation within + + align:start position:0% +and then there's variation within + + + align:start position:0% +and then there's variation within +classrooms to allow us to look at + + align:start position:0% +classrooms to allow us to look at + + + align:start position:0% +classrooms to allow us to look at +the role of personal interactions that + + align:start position:0% +the role of personal interactions that + + + align:start position:0% +the role of personal interactions that +sort of idiosyncratic assignments to + + align:start position:0% +sort of idiosyncratic assignments to + + + align:start position:0% +sort of idiosyncratic assignments to +study groups + + align:start position:0% +study groups + + + align:start position:0% +study groups +so some students happen to be in study + + align:start position:0% +so some students happen to be in study + + + align:start position:0% +so some students happen to be in study +groups with a poor kid and others + + align:start position:0% +groups with a poor kid and others + + + align:start position:0% +groups with a poor kid and others +were not + + align:start position:0% +were not + + + align:start position:0% +were not +now what does the study measure the + + align:start position:0% +now what does the study measure the + + + align:start position:0% +now what does the study measure the +study measures three broad set of + + align:start position:0% +study measures three broad set of + + + align:start position:0% +study measures three broad set of +outcomes + + align:start position:0% +outcomes + + + align:start position:0% +outcomes +it matters pro-social behavior and + + align:start position:0% +it matters pro-social behavior and + + + align:start position:0% +it matters pro-social behavior and +generosity this is very much what we + + align:start position:0% +generosity this is very much what we + + + align:start position:0% +generosity this is very much what we +have already looked at + + align:start position:0% +have already looked at + + + align:start position:0% +have already looked at +in particular it looks at dictator games + + align:start position:0% +in particular it looks at dictator games + + + align:start position:0% +in particular it looks at dictator games +and voluntary volunteering + + align:start position:0% +and voluntary volunteering + + + align:start position:0% +and voluntary volunteering +for charities at school the paper has a + + align:start position:0% +for charities at school the paper has a + + + align:start position:0% +for charities at school the paper has a +very nice + + align:start position:0% +very nice + + + align:start position:0% +very nice +mix of laboratory outcomes sort of + + align:start position:0% +mix of laboratory outcomes sort of + + + align:start position:0% +mix of laboratory outcomes sort of +measured in the field which is sort of + + align:start position:0% +measured in the field which is sort of + + + align:start position:0% +measured in the field which is sort of +the dictator games that you're all + + align:start position:0% +the dictator games that you're all + + + align:start position:0% +the dictator games that you're all +familiar with + + align:start position:0% +familiar with + + + align:start position:0% +familiar with +and field outcomes which is sort of + + align:start position:0% +and field outcomes which is sort of + + + align:start position:0% +and field outcomes which is sort of +trying to + + align:start position:0% +trying to + + + align:start position:0% +trying to +collect real-world outcomes in the sense + + align:start position:0% +collect real-world outcomes in the sense + + + align:start position:0% +collect real-world outcomes in the sense +of like things that are perhaps somewhat + + align:start position:0% +of like things that are perhaps somewhat + + + align:start position:0% +of like things that are perhaps somewhat +less contrived + + align:start position:0% +less contrived + + + align:start position:0% +less contrived +from the perspective of like kids in + + align:start position:0% +from the perspective of like kids in + + + align:start position:0% +from the perspective of like kids in +school and + + align:start position:0% +school and + + + align:start position:0% +school and +what's very nice about the study is that + + align:start position:0% +what's very nice about the study is that + + + align:start position:0% +what's very nice about the study is that +it seems to be that the results are very + + align:start position:0% +it seems to be that the results are very + + + align:start position:0% +it seems to be that the results are very +much aligned + + align:start position:0% +much aligned + + + align:start position:0% +much aligned +between sort of these lab outcomes the + + align:start position:0% +between sort of these lab outcomes the + + + align:start position:0% +between sort of these lab outcomes the +dictator game type outcomes + + align:start position:0% +dictator game type outcomes + + + align:start position:0% +dictator game type outcomes +and the field outcomes for just + + align:start position:0% +and the field outcomes for just + + + align:start position:0% +and the field outcomes for just +volunteering for charity at school in + + align:start position:0% +volunteering for charity at school in + + + align:start position:0% +volunteering for charity at school in +this case + + align:start position:0% +this case + + + align:start position:0% +this case +second the author looks at + + align:start position:0% +second the author looks at + + + align:start position:0% +second the author looks at +discrimination and social interactions + + align:start position:0% +discrimination and social interactions + + + align:start position:0% +discrimination and social interactions +in particular he does a little sports + + align:start position:0% +in particular he does a little sports + + + align:start position:0% +in particular he does a little sports +contest and looks at teammate selection + + align:start position:0% +contest and looks at teammate selection + + + align:start position:0% +contest and looks at teammate selection +among these students and then + + align:start position:0% +among these students and then + + + align:start position:0% +among these students and then +willingness to attend play dates with + + align:start position:0% +willingness to attend play dates with + + + align:start position:0% +willingness to attend play dates with +poor students finally the author also + + align:start position:0% +poor students finally the author also + + + align:start position:0% +poor students finally the author also +looks at academic outcomes in particular + + align:start position:0% +looks at academic outcomes in particular + + + align:start position:0% +looks at academic outcomes in particular +test scores and disciplinary infractions + + align:start position:0% +test scores and disciplinary infractions + + + align:start position:0% +test scores and disciplinary infractions +now why might one want to look at + + align:start position:0% +now why might one want to look at + + + align:start position:0% +now why might one want to look at +academic outcomes and why are we + + align:start position:0% +academic outcomes and why are we + + + align:start position:0% +academic outcomes and why are we +interested in social preferences + + align:start position:0% +interested in social preferences + + + align:start position:0% +interested in social preferences +there's several reasons for that in + + align:start position:0% +there's several reasons for that in + + + align:start position:0% +there's several reasons for that in +particular an important reason here is + + align:start position:0% +particular an important reason here is + + + align:start position:0% +particular an important reason here is +that + + align:start position:0% +that + + + align:start position:0% +that +um uh if you're against this type of + + align:start position:0% +um uh if you're against this type of + + + align:start position:0% +um uh if you're against this type of +policy i might sort of show you that + + align:start position:0% +policy i might sort of show you that + + + align:start position:0% +policy i might sort of show you that +oh you know adding poor children um uh + + align:start position:0% +oh you know adding poor children um uh + + + align:start position:0% +oh you know adding poor children um uh +might affect the the social preference + + align:start position:0% +might affect the the social preference + + + align:start position:0% +might affect the the social preference +of rich children and so on in various + + align:start position:0% +of rich children and so on in various + + + align:start position:0% +of rich children and so on in various +ways maybe discrimination goes down but + + align:start position:0% +ways maybe discrimination goes down but + + + align:start position:0% +ways maybe discrimination goes down but +perhaps it's the case that that all + + align:start position:0% +perhaps it's the case that that all + + + align:start position:0% +perhaps it's the case that that all +comes at the cost of academic + + align:start position:0% +comes at the cost of academic + + + align:start position:0% +comes at the cost of academic +performance + + align:start position:0% +performance + + + align:start position:0% +performance +but if you're trying to sort of + + align:start position:0% +but if you're trying to sort of + + + align:start position:0% +but if you're trying to sort of +implement this policy and uh + + align:start position:0% +implement this policy and uh + + + align:start position:0% +implement this policy and uh +you know persuade policy makers maybe + + align:start position:0% +you know persuade policy makers maybe + + + align:start position:0% +you know persuade policy makers maybe +teachers + + align:start position:0% +teachers + + + align:start position:0% +teachers +um or parents of like okay let's have + + align:start position:0% +um or parents of like okay let's have + + + align:start position:0% +um or parents of like okay let's have +more + + align:start position:0% +more + + + align:start position:0% +more +poor students in in in in your school + + align:start position:0% +poor students in in in in your school + + + align:start position:0% +poor students in in in in your school +well parents might sort of be okay fine + + align:start position:0% +well parents might sort of be okay fine + + + align:start position:0% +well parents might sort of be okay fine +there's going to be like some change in + + align:start position:0% +there's going to be like some change in + + + align:start position:0% +there's going to be like some change in +social preferences + + align:start position:0% +social preferences + + + align:start position:0% +social preferences +some change in discrimination but really + + align:start position:0% +some change in discrimination but really + + + align:start position:0% +some change in discrimination but really +what we care about is um + + align:start position:0% +what we care about is um + + + align:start position:0% +what we care about is um +uh test scores or um discipline at + + align:start position:0% +uh test scores or um discipline at + + + align:start position:0% +uh test scores or um discipline at +school and these poor kids might not be + + align:start position:0% +school and these poor kids might not be + + + align:start position:0% +school and these poor kids might not be +um might be worse in terms of like test + + align:start position:0% +um might be worse in terms of like test + + + align:start position:0% +um might be worse in terms of like test +scores + + align:start position:0% +scores + + + align:start position:0% +scores +and they might have like negative peer + + align:start position:0% +and they might have like negative peer + + + align:start position:0% +and they might have like negative peer +effects in terms of like + + align:start position:0% +effects in terms of like + + + align:start position:0% +effects in terms of like +um a test scores but also in terms of + + align:start position:0% +um a test scores but also in terms of + + + align:start position:0% +um a test scores but also in terms of +disciplinary + + align:start position:0% +disciplinary + + + align:start position:0% +disciplinary +infractions and sort of as a policy + + align:start position:0% +infractions and sort of as a policy + + + align:start position:0% +infractions and sort of as a policy +question then it's really important to + + align:start position:0% +question then it's really important to + + + align:start position:0% +question then it's really important to +understand + + align:start position:0% +understand + + + align:start position:0% +understand +if there are some benefits in terms of + + align:start position:0% +if there are some benefits in terms of + + + align:start position:0% +if there are some benefits in terms of +pro-sociality or + + align:start position:0% +pro-sociality or + + + align:start position:0% +pro-sociality or +reduced discrimination do these benefits + + align:start position:0% +reduced discrimination do these benefits + + + align:start position:0% +reduced discrimination do these benefits +come at the cost of + + align:start position:0% +come at the cost of + + + align:start position:0% +come at the cost of +reduced academic performance + + align:start position:0% + + + + align:start position:0% + +okay so now what is in fact the policy + + align:start position:0% +okay so now what is in fact the policy + + + align:start position:0% +okay so now what is in fact the policy +innovation in delhi in 2007 + + align:start position:0% +innovation in delhi in 2007 + + + align:start position:0% +innovation in delhi in 2007 +there was a 20 admissions quota in + + align:start position:0% +there was a 20 admissions quota in + + + align:start position:0% +there was a 20 admissions quota in +private schools introduced + + align:start position:0% +private schools introduced + + + align:start position:0% +private schools introduced +for poor students in some of these + + align:start position:0% +for poor students in some of these + + + align:start position:0% +for poor students in some of these +private schools there's a household + + align:start position:0% +private schools there's a household + + + align:start position:0% +private schools there's a household +income + + align:start position:0% +income + + + align:start position:0% +income +cut off of two thousand dollars per year + + align:start position:0% +cut off of two thousand dollars per year + + + align:start position:0% +cut off of two thousand dollars per year +so these are not sort of the poorest of + + align:start position:0% +so these are not sort of the poorest of + + + align:start position:0% +so these are not sort of the poorest of +the poor of the students + + align:start position:0% +the poor of the students + + + align:start position:0% +the poor of the students +who who are qualified + + align:start position:0% +who who are qualified + + + align:start position:0% +who who are qualified +schools which received subsidy + + align:start position:0% +schools which received subsidy + + + align:start position:0% +schools which received subsidy +subsidized land from the government um + + align:start position:0% +subsidized land from the government um + + + align:start position:0% +subsidized land from the government um +were essentially um uh uh uh included in + + align:start position:0% +were essentially um uh uh uh included in + + + align:start position:0% +were essentially um uh uh uh included in +this policy change + + align:start position:0% +this policy change + + + align:start position:0% +this policy change +that's over 90 of elite private schools + + align:start position:0% +that's over 90 of elite private schools + + + align:start position:0% +that's over 90 of elite private schools +so think of these elite private schools + + align:start position:0% +so think of these elite private schools + + + align:start position:0% +so think of these elite private schools +these are really sort of like + + align:start position:0% +these are really sort of like + + + align:start position:0% +these are really sort of like +very rich kids or parents + + align:start position:0% +very rich kids or parents + + + align:start position:0% +very rich kids or parents +of these kids there was no fees for the + + align:start position:0% +of these kids there was no fees for the + + + align:start position:0% +of these kids there was no fees for the +poor kids because you know they would + + align:start position:0% +poor kids because you know they would + + + align:start position:0% +poor kids because you know they would +not be able to afford these fees anyway + + align:start position:0% +not be able to afford these fees anyway + + + align:start position:0% +not be able to afford these fees anyway +there was importantly also no tracking + + align:start position:0% +there was importantly also no tracking + + + align:start position:0% +there was importantly also no tracking +so it wasn't that like + + align:start position:0% +so it wasn't that like + + + align:start position:0% +so it wasn't that like +a high ability or high performance kids + + align:start position:0% +a high ability or high performance kids + + + align:start position:0% +a high ability or high performance kids +who do very well + + align:start position:0% +who do very well + + + align:start position:0% +who do very well +were like tracked in the lake high + + align:start position:0% +were like tracked in the lake high + + + align:start position:0% +were like tracked in the lake high +tracks and the good good tracks versus + + align:start position:0% +tracks and the good good tracks versus + + + align:start position:0% +tracks and the good good tracks versus +lower tracks + + align:start position:0% +lower tracks + + + align:start position:0% +lower tracks +instead everybody was mixed together + + align:start position:0% +instead everybody was mixed together + + + align:start position:0% +instead everybody was mixed together +poor and rich high performing low + + align:start position:0% +poor and rich high performing low + + + align:start position:0% +poor and rich high performing low +performing + + align:start position:0% +performing + + + align:start position:0% +performing +students and the poor kids were selected + + align:start position:0% +students and the poor kids were selected + + + align:start position:0% +students and the poor kids were selected +using lotteries + + align:start position:0% +using lotteries + + + align:start position:0% +using lotteries +which in principle also allows the + + align:start position:0% +which in principle also allows the + + + align:start position:0% +which in principle also allows the +author or others to look at + + align:start position:0% +author or others to look at + + + align:start position:0% +author or others to look at +the effect on those poor kids the + + align:start position:0% +the effect on those poor kids the + + + align:start position:0% +the effect on those poor kids the +students who are selected versus not + + align:start position:0% +students who are selected versus not + + + align:start position:0% +students who are selected versus not +to be clear this is not the subject of + + align:start position:0% +to be clear this is not the subject of + + + align:start position:0% +to be clear this is not the subject of +this paper + + align:start position:0% +this paper + + + align:start position:0% +this paper +just to give you a sense of the + + align:start position:0% +just to give you a sense of the + + + align:start position:0% +just to give you a sense of the +magnitude of like the + + align:start position:0% +magnitude of like the + + + align:start position:0% +magnitude of like the +uh uh the mixing you see i said um + + align:start position:0% +uh uh the mixing you see i said um + + + align:start position:0% +uh uh the mixing you see i said um +uh the average beneficiary um uh was + + align:start position:0% +uh the average beneficiary um uh was + + + align:start position:0% +uh the average beneficiary um uh was +sort of at the 25th um + + align:start position:0% +sort of at the 25th um + + + align:start position:0% +sort of at the 25th um +uh percentile of the uh income + + align:start position:0% +uh percentile of the uh income + + + align:start position:0% +uh percentile of the uh income +distribution in in + + align:start position:0% +distribution in in + + + align:start position:0% +distribution in in +in in delhi uh and wealthy students are + + align:start position:0% +in in delhi uh and wealthy students are + + + align:start position:0% +in in delhi uh and wealthy students are +very much on the + + align:start position:0% +very much on the + + + align:start position:0% +very much on the +um on the right tail + + align:start position:0% +um on the right tail + + + align:start position:0% +um on the right tail +sorry on the right tail of the + + align:start position:0% +sorry on the right tail of the + + + align:start position:0% +sorry on the right tail of the +distribution uh + + align:start position:0% +distribution uh + + + align:start position:0% +distribution uh +something like the 90th percentile 95th + + align:start position:0% +something like the 90th percentile 95th + + + align:start position:0% +something like the 90th percentile 95th +percentile which is about + + align:start position:0% +percentile which is about + + + align:start position:0% +percentile which is about +the west equivalent of that would be + + align:start position:0% +the west equivalent of that would be + + + align:start position:0% +the west equivalent of that would be +about two hundred thousand dollars um + + align:start position:0% +about two hundred thousand dollars um + + + align:start position:0% +about two hundred thousand dollars um +per year + + align:start position:0% +per year + + + align:start position:0% +per year +the average um uh beneficiary had like a + + align:start position:0% +the average um uh beneficiary had like a + + + align:start position:0% +the average um uh beneficiary had like a +u.s equivalent income of + + align:start position:0% +u.s equivalent income of + + + align:start position:0% +u.s equivalent income of +like 23 000 again these are not the + + align:start position:0% +like 23 000 again these are not the + + + align:start position:0% +like 23 000 again these are not the +poorest of the poor but relatively poor + + align:start position:0% +poorest of the poor but relatively poor + + + align:start position:0% +poorest of the poor but relatively poor +as about like an order of magnitude + + align:start position:0% +as about like an order of magnitude + + + align:start position:0% +as about like an order of magnitude +poorer than the average person in the + + align:start position:0% +poorer than the average person in the + + + align:start position:0% +poorer than the average person in the +actual school + + align:start position:0% +actual school + + + align:start position:0% +actual school +now this policy then induced large + + align:start position:0% +now this policy then induced large + + + align:start position:0% +now this policy then induced large +variation + + align:start position:0% +variation + + + align:start position:0% +variation +across classrooms you look at + + align:start position:0% +across classrooms you look at + + + align:start position:0% +across classrooms you look at +poor students in the fraction of for the + + align:start position:0% +poor students in the fraction of for the + + + align:start position:0% +poor students in the fraction of for the +number so you have poor students + + align:start position:0% +number so you have poor students + + + align:start position:0% +number so you have poor students +in by grade in 2011. i told you this + + align:start position:0% +in by grade in 2011. i told you this + + + align:start position:0% +in by grade in 2011. i told you this +the policy innovation was in 2007. so if + + align:start position:0% +the policy innovation was in 2007. so if + + + align:start position:0% +the policy innovation was in 2007. so if +you look in 2011 that's four years + + align:start position:0% +you look in 2011 that's four years + + + align:start position:0% +you look in 2011 that's four years +later anybody who is in + + align:start position:0% +later anybody who is in + + + align:start position:0% +later anybody who is in +grade four in 2011 has essentially + + align:start position:0% +grade four in 2011 has essentially + + + align:start position:0% +grade four in 2011 has essentially +no poor student in their class in those + + align:start position:0% +no poor student in their class in those + + + align:start position:0% +no poor student in their class in those +rich + + align:start position:0% +rich + + + align:start position:0% +rich +schools so for students who are in 2011 + + align:start position:0% +schools so for students who are in 2011 + + + align:start position:0% +schools so for students who are in 2011 +and grade four + + align:start position:0% +and grade four + + + align:start position:0% +and grade four +five or six that policy came too late + + align:start position:0% +five or six that policy came too late + + + align:start position:0% +five or six that policy came too late +they do not have any + + align:start position:0% +they do not have any + + + align:start position:0% +they do not have any +poor classmates in contrast if you look + + align:start position:0% +poor classmates in contrast if you look + + + align:start position:0% +poor classmates in contrast if you look +at + + align:start position:0% + + + + align:start position:0% + +the lower grades grades three two one + + align:start position:0% +the lower grades grades three two one + + + align:start position:0% +the lower grades grades three two one +and zero which are essentially uh + + align:start position:0% +and zero which are essentially uh + + + align:start position:0% +and zero which are essentially uh +preschool or zero minus one which is + + align:start position:0% +preschool or zero minus one which is + + + align:start position:0% +preschool or zero minus one which is +preschool grades + + align:start position:0% +preschool grades + + + align:start position:0% +preschool grades +uh there's lots of additional poor + + align:start position:0% +uh there's lots of additional poor + + + align:start position:0% +uh there's lots of additional poor +students now + + align:start position:0% +students now + + + align:start position:0% +students now +uh in those uh uh rich schools + + align:start position:0% +uh in those uh uh rich schools + + + align:start position:0% +uh in those uh uh rich schools +now again uh there's variation within + + align:start position:0% +now again uh there's variation within + + + align:start position:0% +now again uh there's variation within +schools and across schools the variation + + align:start position:0% +schools and across schools the variation + + + align:start position:0% +schools and across schools the variation +within schools is across classrooms + + align:start position:0% +within schools is across classrooms + + + align:start position:0% +within schools is across classrooms +that's kind of what i'm showing you + + align:start position:0% +that's kind of what i'm showing you + + + align:start position:0% +that's kind of what i'm showing you +um here um but there's also variation + + align:start position:0% +um here um but there's also variation + + + align:start position:0% +um here um but there's also variation +uh across schools so just to be clear + + align:start position:0% +uh across schools so just to be clear + + + align:start position:0% +uh across schools so just to be clear +the variation within schools + + align:start position:0% +the variation within schools + + + align:start position:0% +the variation within schools +across classrooms is like in the treated + + align:start position:0% +across classrooms is like in the treated + + + align:start position:0% +across classrooms is like in the treated +schools + + align:start position:0% +schools + + + align:start position:0% +schools +um there's some classes like the fourth + + align:start position:0% +um there's some classes like the fourth + + + align:start position:0% +um there's some classes like the fourth +grade + + align:start position:0% +grade + + + align:start position:0% +grade +have like essentially zero poor kids in + + align:start position:0% +have like essentially zero poor kids in + + + align:start position:0% +have like essentially zero poor kids in +their classes + + align:start position:0% +their classes + + + align:start position:0% +their classes +and uh the third grade in contrast + + align:start position:0% +and uh the third grade in contrast + + + align:start position:0% +and uh the third grade in contrast +have um lots of poor poor kids + + align:start position:0% +have um lots of poor poor kids + + + align:start position:0% +have um lots of poor poor kids +in the classroom we can do that + + align:start position:0% +in the classroom we can do that + + + align:start position:0% +in the classroom we can do that +comparison uh across classrooms within + + align:start position:0% +comparison uh across classrooms within + + + align:start position:0% +comparison uh across classrooms within +school + + align:start position:0% +school + + + align:start position:0% +school +in addition there's also variation + + align:start position:0% +in addition there's also variation + + + align:start position:0% +in addition there's also variation +across schools there's in particular + + align:start position:0% +across schools there's in particular + + + align:start position:0% +across schools there's in particular +there's treatment schools + + align:start position:0% +there's treatment schools + + + align:start position:0% +there's treatment schools +um which comply in 2007 as they were + + align:start position:0% +um which comply in 2007 as they were + + + align:start position:0% +um which comply in 2007 as they were +supposed to + + align:start position:0% +supposed to + + + align:start position:0% +supposed to +but then there's also delayed treatment + + align:start position:0% +but then there's also delayed treatment + + + align:start position:0% +but then there's also delayed treatment +schools which complied in 2008 + + align:start position:0% +schools which complied in 2008 + + + align:start position:0% +schools which complied in 2008 +so the jump shifted by one quart so the + + align:start position:0% +so the jump shifted by one quart so the + + + align:start position:0% +so the jump shifted by one quart so the +court the jump that i showed you here + + align:start position:0% +court the jump that i showed you here + + + align:start position:0% +court the jump that i showed you here +um this is for the treatment schools + + align:start position:0% +um this is for the treatment schools + + + align:start position:0% +um this is for the treatment schools +that + + align:start position:0% +that + + + align:start position:0% +that +complied uh or this is for everybody + + align:start position:0% +complied uh or this is for everybody + + + align:start position:0% +complied uh or this is for everybody +that complied in 2007 + + align:start position:0% +that complied in 2007 + + + align:start position:0% +that complied in 2007 +the delayed one complete a year later so + + align:start position:0% +the delayed one complete a year later so + + + align:start position:0% +the delayed one complete a year later so +you see them essentially + + align:start position:0% +you see them essentially + + + align:start position:0% +you see them essentially +somewhat later um uh increasing or one + + align:start position:0% +somewhat later um uh increasing or one + + + align:start position:0% +somewhat later um uh increasing or one +year later exactly + + align:start position:0% +year later exactly + + + align:start position:0% +year later exactly +increasing the fraction of poor kids in + + align:start position:0% +increasing the fraction of poor kids in + + + align:start position:0% +increasing the fraction of poor kids in +their classroom and then there's the + + align:start position:0% +their classroom and then there's the + + + align:start position:0% +their classroom and then there's the +control schools they were not subject to + + align:start position:0% +control schools they were not subject to + + + align:start position:0% +control schools they were not subject to +the policy at least until 2013 + + align:start position:0% +the policy at least until 2013 + + + align:start position:0% +the policy at least until 2013 +so they had received + + align:start position:0% +so they had received + + + align:start position:0% +so they had received +they had received land from federal + + align:start position:0% +they had received land from federal + + + align:start position:0% +they had received land from federal +government or private foundations + + align:start position:0% +government or private foundations + + + align:start position:0% +government or private foundations +so essentially there was no treatment uh + + align:start position:0% +so essentially there was no treatment uh + + + align:start position:0% +so essentially there was no treatment uh +that is all students are rich in these + + align:start position:0% +that is all students are rich in these + + + align:start position:0% +that is all students are rich in these +types of classes + + align:start position:0% +types of classes + + + align:start position:0% +types of classes +so that was the the land receiving is + + align:start position:0% +so that was the the land receiving is + + + align:start position:0% +so that was the the land receiving is +essentially just uh that was like a + + align:start position:0% +essentially just uh that was like a + + + align:start position:0% +essentially just uh that was like a +fairly arbitrary rule in some ways uh so + + align:start position:0% +fairly arbitrary rule in some ways uh so + + + align:start position:0% +fairly arbitrary rule in some ways uh so +that sort of leads to + + align:start position:0% +that sort of leads to + + + align:start position:0% +that sort of leads to +at least quasi-random variation and some + + align:start position:0% +at least quasi-random variation and some + + + align:start position:0% +at least quasi-random variation and some +schools uh received + + align:start position:0% +schools uh received + + + align:start position:0% +schools uh received +the treatment and others um did not + + align:start position:0% +the treatment and others um did not + + + align:start position:0% +the treatment and others um did not +um now let me show you some outcomes so + + align:start position:0% +um now let me show you some outcomes so + + + align:start position:0% +um now let me show you some outcomes so +one outcome is our friend the dictator + + align:start position:0% +one outcome is our friend the dictator + + + align:start position:0% +one outcome is our friend the dictator +game which you've seen quite a bit and + + align:start position:0% +game which you've seen quite a bit and + + + align:start position:0% +game which you've seen quite a bit and +played already + + align:start position:0% +played already + + + align:start position:0% +played already +as well is students are allowed with 10 + + align:start position:0% +as well is students are allowed with 10 + + + align:start position:0% +as well is students are allowed with 10 +rupees + + align:start position:0% +rupees + + + align:start position:0% +rupees +which is you know not very much that's + + align:start position:0% +which is you know not very much that's + + + align:start position:0% +which is you know not very much that's +about like 15 um + + align:start position:0% +about like 15 um + + + align:start position:0% +about like 15 um +cents and they choose to share um notice + + align:start position:0% +cents and they choose to share um notice + + + align:start position:0% +cents and they choose to share um notice +that these are + + align:start position:0% +that these are + + + align:start position:0% +that these are +pretty pretty young kids so 10 rupees is + + align:start position:0% +pretty pretty young kids so 10 rupees is + + + align:start position:0% +pretty pretty young kids so 10 rupees is +quite a bit of money for them they + + align:start position:0% +quite a bit of money for them they + + + align:start position:0% +quite a bit of money for them they +choose to share + + align:start position:0% +choose to share + + + align:start position:0% +choose to share +an amount as before between 0 and 10. + + align:start position:0% +an amount as before between 0 and 10. + + + align:start position:0% +an amount as before between 0 and 10. +and + + align:start position:0% +and + + + align:start position:0% +and +i got them sets this up such that + + align:start position:0% +i got them sets this up such that + + + align:start position:0% +i got them sets this up such that +students could it was not just about the + + align:start position:0% +students could it was not just about the + + + align:start position:0% +students could it was not just about the +money but they also can exchange the + + align:start position:0% +money but they also can exchange the + + + align:start position:0% +money but they also can exchange the +money for candy later + + align:start position:0% +money for candy later + + + align:start position:0% +money for candy later +add one rupee per piece so that was a + + align:start position:0% +add one rupee per piece so that was a + + + align:start position:0% +add one rupee per piece so that was a +pretty um good deal + + align:start position:0% +pretty um good deal + + + align:start position:0% +pretty um good deal +then um the dictator games for the order + + align:start position:0% +then um the dictator games for the order + + + align:start position:0% +then um the dictator games for the order +was randomized the + + align:start position:0% +was randomized the + + + align:start position:0% +was randomized the +kids would play two games again these + + align:start position:0% +kids would play two games again these + + + align:start position:0% +kids would play two games again these +are all rich kids who do that + + align:start position:0% +are all rich kids who do that + + + align:start position:0% +are all rich kids who do that +they play first game one where the + + align:start position:0% +they play first game one where the + + + align:start position:0% +they play first game one where the +recipient is a poor student in a school + + align:start position:0% +recipient is a poor student in a school + + + align:start position:0% +recipient is a poor student in a school +for poor children + + align:start position:0% +for poor children + + + align:start position:0% +for poor children +and in game two it's a rich student in a + + align:start position:0% +and in game two it's a rich student in a + + + align:start position:0% +and in game two it's a rich student in a +private control school + + align:start position:0% +private control school + + + align:start position:0% +private control school +notice it's a control school to be clear + + align:start position:0% +notice it's a control school to be clear + + + align:start position:0% +notice it's a control school to be clear +so it's not a kid that they might know + + align:start position:0% +so it's not a kid that they might know + + + align:start position:0% +so it's not a kid that they might know +so the kids are + + align:start position:0% +so the kids are + + + align:start position:0% +so the kids are +chosen such that the kids were + + align:start position:0% +chosen such that the kids were + + + align:start position:0% +chosen such that the kids were +given the names and the photographs of + + align:start position:0% +given the names and the photographs of + + + align:start position:0% +given the names and the photographs of +the school shown to the subject to the + + align:start position:0% +the school shown to the subject to the + + + align:start position:0% +the school shown to the subject to the +kids + + align:start position:0% +kids + + + align:start position:0% +kids +so you could sort of see and this is + + align:start position:0% +so you could sort of see and this is + + + align:start position:0% +so you could sort of see and this is +verified in the briefing by the author + + align:start position:0% +verified in the briefing by the author + + + align:start position:0% +verified in the briefing by the author +is that the the the children understand + + align:start position:0% +is that the the the children understand + + + align:start position:0% +is that the the the children understand +very well + + align:start position:0% +very well + + + align:start position:0% +very well +who's a rich kid and who's a poor kid um + + align:start position:0% +who's a rich kid and who's a poor kid um + + + align:start position:0% +who's a rich kid and who's a poor kid um +but these are not kids that they would + + align:start position:0% +but these are not kids that they would + + + align:start position:0% +but these are not kids that they would +actually know + + align:start position:0% +actually know + + + align:start position:0% +actually know +and something that's a less interesting + + align:start position:0% +and something that's a less interesting + + + align:start position:0% +and something that's a less interesting +question if you have gone + + align:start position:0% +question if you have gone + + + align:start position:0% +question if you have gone +to school with somebody for a long time + + align:start position:0% +to school with somebody for a long time + + + align:start position:0% +to school with somebody for a long time +you might have seen them around + + align:start position:0% +you might have seen them around + + + align:start position:0% +you might have seen them around +in your schoolyard you might be nicer to + + align:start position:0% +in your schoolyard you might be nicer to + + + align:start position:0% +in your schoolyard you might be nicer to +them or less nice to them + + align:start position:0% +them or less nice to them + + + align:start position:0% +them or less nice to them +that's not what the study is looking at + + align:start position:0% +that's not what the study is looking at + + + align:start position:0% +that's not what the study is looking at +the study is looking at + + align:start position:0% +the study is looking at + + + align:start position:0% +the study is looking at +other kids in other schools that look + + align:start position:0% +other kids in other schools that look + + + align:start position:0% +other kids in other schools that look +rich + + align:start position:0% +rich + + + align:start position:0% +rich +or look poor um both in terms of like + + align:start position:0% +or look poor um both in terms of like + + + align:start position:0% +or look poor um both in terms of like +the way um + + align:start position:0% +the way um + + + align:start position:0% +the way um +uh uh they're dressed and so on but in + + align:start position:0% +uh uh they're dressed and so on but in + + + align:start position:0% +uh uh they're dressed and so on but in +particular the way their school + + align:start position:0% +particular the way their school + + + align:start position:0% +particular the way their school +looks like so essentially these are now + + align:start position:0% +looks like so essentially these are now + + + align:start position:0% +looks like so essentially these are now +we're looking at social preferences + + align:start position:0% +we're looking at social preferences + + + align:start position:0% +we're looking at social preferences +towards + + align:start position:0% +towards + + + align:start position:0% +towards +other people people that these kids + + align:start position:0% +other people people that these kids + + + align:start position:0% +other people people that these kids +don't know + + align:start position:0% +don't know + + + align:start position:0% +don't know +okay so now what do we see so this is + + align:start position:0% +okay so now what do we see so this is + + + align:start position:0% +okay so now what do we see so this is +the generosity + + align:start position:0% +the generosity + + + align:start position:0% +the generosity +to the poor so like this is essentially + + align:start position:0% +to the poor so like this is essentially + + + align:start position:0% +to the poor so like this is essentially +the results from game number one + + align:start position:0% +the results from game number one + + + align:start position:0% +the results from game number one +again remember these are all um rich + + align:start position:0% +again remember these are all um rich + + + align:start position:0% +again remember these are all um rich +kids who are giving now to poor kids and + + align:start position:0% +kids who are giving now to poor kids and + + + align:start position:0% +kids who are giving now to poor kids and +the question now is + + align:start position:0% +the question now is + + + align:start position:0% +the question now is +is being exposed to or does being + + align:start position:0% +is being exposed to or does being + + + align:start position:0% +is being exposed to or does being +exposed to poor children + + align:start position:0% +exposed to poor children + + + align:start position:0% +exposed to poor children +um uh uh uh for several years + + align:start position:0% +um uh uh uh for several years + + + align:start position:0% +um uh uh uh for several years +does that affect um uh giving + + align:start position:0% +does that affect um uh giving + + + align:start position:0% +does that affect um uh giving +uh in the form of dictator games + + align:start position:0% +uh in the form of dictator games + + + align:start position:0% +uh in the form of dictator games +towards poor children to start with + + align:start position:0% +towards poor children to start with + + + align:start position:0% +towards poor children to start with +we're going to talk about rich students + + align:start position:0% +we're going to talk about rich students + + + align:start position:0% +we're going to talk about rich students +after that so here you see the + + align:start position:0% +after that so here you see the + + + align:start position:0% +after that so here you see the +generosity to the poor and controlled + + align:start position:0% +generosity to the poor and controlled + + + align:start position:0% +generosity to the poor and controlled +schools + + align:start position:0% +schools + + + align:start position:0% +schools +you see this is the percent given to the + + align:start position:0% +you see this is the percent given to the + + + align:start position:0% +you see this is the percent given to the +poor recipient + + align:start position:0% +poor recipient + + + align:start position:0% +poor recipient +it's remarkably similar to what we've + + align:start position:0% +it's remarkably similar to what we've + + + align:start position:0% +it's remarkably similar to what we've +seen previously which is about 28 or 30 + + align:start position:0% +seen previously which is about 28 or 30 + + + align:start position:0% +seen previously which is about 28 or 30 +percent about 25 + + align:start position:0% +percent about 25 + + + align:start position:0% +percent about 25 +is given to the poor uh kid in the + + align:start position:0% +is given to the poor uh kid in the + + + align:start position:0% +is given to the poor uh kid in the +control groups + + align:start position:0% +control groups + + + align:start position:0% +control groups +uh in the control schools um this + + align:start position:0% +uh in the control schools um this + + + align:start position:0% +uh in the control schools um this +fraction + + align:start position:0% +fraction + + + align:start position:0% +fraction +trend seems to trend up a little bit + + align:start position:0% +trend seems to trend up a little bit + + + align:start position:0% +trend seems to trend up a little bit +over time but it's also quite constant + + align:start position:0% +over time but it's also quite constant + + + align:start position:0% +over time but it's also quite constant +over time across grades you see here + + align:start position:0% +over time across grades you see here + + + align:start position:0% +over time across grades you see here +grades two + + align:start position:0% +grades two + + + align:start position:0% +grades two +three four and five on the x-axis and + + align:start position:0% +three four and five on the x-axis and + + + align:start position:0% +three four and five on the x-axis and +the y-axis is the percent given to the + + align:start position:0% +the y-axis is the percent given to the + + + align:start position:0% +the y-axis is the percent given to the +poor recipients + + align:start position:0% +poor recipients + + + align:start position:0% +poor recipients +now adding the treatment schools now we + + align:start position:0% +now adding the treatment schools now we + + + align:start position:0% +now adding the treatment schools now we +find uh + + align:start position:0% +find uh + + + align:start position:0% +find uh +that for two grades for grade two and + + align:start position:0% +that for two grades for grade two and + + + align:start position:0% +that for two grades for grade two and +grade three + + align:start position:0% +grade three + + + align:start position:0% +grade three +remember the graph that i showed you + + align:start position:0% +remember the graph that i showed you + + + align:start position:0% +remember the graph that i showed you +here you see that + + align:start position:0% +here you see that + + + align:start position:0% +here you see that +in grades three two one and so on these + + align:start position:0% +in grades three two one and so on these + + + align:start position:0% +in grades three two one and so on these +are the kids who are exposed + + align:start position:0% +are the kids who are exposed + + + align:start position:0% +are the kids who are exposed +to the poor children in class in + + align:start position:0% +to the poor children in class in + + + align:start position:0% +to the poor children in class in +contrast to grades four and five that + + align:start position:0% +contrast to grades four and five that + + + align:start position:0% +contrast to grades four and five that +have not been exposed to poor kids in + + align:start position:0% +have not been exposed to poor kids in + + + align:start position:0% +have not been exposed to poor kids in +their class + + align:start position:0% +their class + + + align:start position:0% +their class +so what this graph note shows is that + + align:start position:0% +so what this graph note shows is that + + + align:start position:0% +so what this graph note shows is that +exactly the grades + + align:start position:0% +exactly the grades + + + align:start position:0% +exactly the grades +three and two that have been exposed in + + align:start position:0% +three and two that have been exposed in + + + align:start position:0% +three and two that have been exposed in +the treatment groups that have been + + align:start position:0% +the treatment groups that have been + + + align:start position:0% +the treatment groups that have been +exposed to poor classmates + + align:start position:0% +exposed to poor classmates + + + align:start position:0% +exposed to poor classmates +these are exactly the students the + + align:start position:0% +these are exactly the students the + + + align:start position:0% +these are exactly the students the +grades where + + align:start position:0% +grades where + + + align:start position:0% +grades where +giving is higher um + + align:start position:0% +giving is higher um + + + align:start position:0% +giving is higher um +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +towards the poor compared to the control + + align:start position:0% +towards the poor compared to the control + + + align:start position:0% +towards the poor compared to the control +groups + + align:start position:0% +groups + + + align:start position:0% +groups +but also compared to the older cohorts + + align:start position:0% +but also compared to the older cohorts + + + align:start position:0% +but also compared to the older cohorts +four and five the grade four and five + + align:start position:0% +four and five the grade four and five + + + align:start position:0% +four and five the grade four and five +when you look at grades four and five + + align:start position:0% +when you look at grades four and five + + + align:start position:0% +when you look at grades four and five +there you see essentially no difference + + align:start position:0% +there you see essentially no difference + + + align:start position:0% +there you see essentially no difference +between treatment and control schools + + align:start position:0% +between treatment and control schools + + + align:start position:0% +between treatment and control schools +so they seem to be very similar in + + align:start position:0% +so they seem to be very similar in + + + align:start position:0% +so they seem to be very similar in +contrast if you look at + + align:start position:0% +contrast if you look at + + + align:start position:0% +contrast if you look at +grades three and through where the + + align:start position:0% +grades three and through where the + + + align:start position:0% +grades three and through where the +treatment uh kids are + + align:start position:0% +treatment uh kids are + + + align:start position:0% +treatment uh kids are +exposed to the treatment by having the + + align:start position:0% +exposed to the treatment by having the + + + align:start position:0% +exposed to the treatment by having the +poor kids in their classrooms + + align:start position:0% +poor kids in their classrooms + + + align:start position:0% +poor kids in their classrooms +these are exactly the years where um + + align:start position:0% +these are exactly the years where um + + + align:start position:0% +these are exactly the years where um +giving goes up and goes up by quite a + + align:start position:0% +giving goes up and goes up by quite a + + + align:start position:0% +giving goes up and goes up by quite a +bit well the average + + align:start position:0% +bit well the average + + + align:start position:0% +bit well the average +was as i said before about 25 that goes + + align:start position:0% +was as i said before about 25 that goes + + + align:start position:0% +was as i said before about 25 that goes +up to about 35 + + align:start position:0% +up to about 35 + + + align:start position:0% +up to about 35 +so that's a pretty large relative + + align:start position:0% +so that's a pretty large relative + + + align:start position:0% +so that's a pretty large relative +increase + + align:start position:0% + + + + align:start position:0% + +now in addition um as i told you there + + align:start position:0% +now in addition um as i told you there + + + align:start position:0% +now in addition um as i told you there +are also delayed treatment groups + + align:start position:0% +are also delayed treatment groups + + + align:start position:0% +are also delayed treatment groups +uh treatment schools so for those + + align:start position:0% +uh treatment schools so for those + + + align:start position:0% +uh treatment schools so for those +schools if you were in grade three + + align:start position:0% +schools if you were in grade three + + + align:start position:0% +schools if you were in grade three +it was also too late for you because the + + align:start position:0% +it was also too late for you because the + + + align:start position:0% +it was also too late for you because the +treatment was introduced only a year + + align:start position:0% +treatment was introduced only a year + + + align:start position:0% +treatment was introduced only a year +later + + align:start position:0% +later + + + align:start position:0% +later +so if you were in grade 3 you did not + + align:start position:0% +so if you were in grade 3 you did not + + + align:start position:0% +so if you were in grade 3 you did not +have any + + align:start position:0% +have any + + + align:start position:0% +have any +poor kids in your school now if you look + + align:start position:0% +poor kids in your school now if you look + + + align:start position:0% +poor kids in your school now if you look +at the yellow line here the yellow line + + align:start position:0% +at the yellow line here the yellow line + + + align:start position:0% +at the yellow line here the yellow line +looks very much like the green line + + align:start position:0% +looks very much like the green line + + + align:start position:0% +looks very much like the green line +that is for the delayed treatment + + align:start position:0% +that is for the delayed treatment + + + align:start position:0% +that is for the delayed treatment +schools there's no impact + + align:start position:0% +schools there's no impact + + + align:start position:0% +schools there's no impact +either they look very much like the + + align:start position:0% +either they look very much like the + + + align:start position:0% +either they look very much like the +control group schools + + align:start position:0% +control group schools + + + align:start position:0% +control group schools +as you would expect however + + align:start position:0% +as you would expect however + + + align:start position:0% +as you would expect however +in the late treatment schools in grade + + align:start position:0% +in the late treatment schools in grade + + + align:start position:0% +in the late treatment schools in grade +number two + + align:start position:0% +number two + + + align:start position:0% +number two +that's the grade where um the students + + align:start position:0% +that's the grade where um the students + + + align:start position:0% +that's the grade where um the students +are exposed + + align:start position:0% +are exposed + + + align:start position:0% +are exposed +the rich students are exposed to the + + align:start position:0% +the rich students are exposed to the + + + align:start position:0% +the rich students are exposed to the +poor kids you will see essentially + + align:start position:0% +poor kids you will see essentially + + + align:start position:0% +poor kids you will see essentially +similar effects + + align:start position:0% +similar effects + + + align:start position:0% +similar effects +to the treatment schools as you expect + + align:start position:0% +to the treatment schools as you expect + + + align:start position:0% +to the treatment schools as you expect +so that's fairly compelling evidence + + align:start position:0% +so that's fairly compelling evidence + + + align:start position:0% +so that's fairly compelling evidence +that really + + align:start position:0% +that really + + + align:start position:0% +that really +the differences that you see across + + align:start position:0% +the differences that you see across + + + align:start position:0% +the differences that you see across +these schools + + align:start position:0% +these schools + + + align:start position:0% +these schools +are driven by the treatment + + align:start position:0% +are driven by the treatment + + + align:start position:0% +are driven by the treatment +that was on the timing of the treatment + + align:start position:0% +that was on the timing of the treatment + + + align:start position:0% +that was on the timing of the treatment +as opposed to + + align:start position:0% +as opposed to + + + align:start position:0% +as opposed to +other potential effects due to like you + + align:start position:0% +other potential effects due to like you + + + align:start position:0% +other potential effects due to like you +know selection or maybe these schools + + align:start position:0% +know selection or maybe these schools + + + align:start position:0% +know selection or maybe these schools +are different and so on + + align:start position:0% +are different and so on + + + align:start position:0% +are different and so on +we see essentially no differences in + + align:start position:0% +we see essentially no differences in + + + align:start position:0% +we see essentially no differences in +grades four and five for + + align:start position:0% +grades four and five for + + + align:start position:0% +grades four and five for +any of the treatment and control schools + + align:start position:0% +any of the treatment and control schools + + + align:start position:0% +any of the treatment and control schools +you also + + align:start position:0% +you also + + + align:start position:0% +you also +see no difference in grade three for the + + align:start position:0% +see no difference in grade three for the + + + align:start position:0% +see no difference in grade three for the +delayed + + align:start position:0% +delayed + + + align:start position:0% +delayed +treatment schools compared to the + + align:start position:0% +treatment schools compared to the + + + align:start position:0% +treatment schools compared to the +control group in contrast + + align:start position:0% +control group in contrast + + + align:start position:0% +control group in contrast +we see clear differences in grade two + + align:start position:0% +we see clear differences in grade two + + + align:start position:0% +we see clear differences in grade two +for the delayed treatment schools + + align:start position:0% +for the delayed treatment schools + + + align:start position:0% +for the delayed treatment schools +compared to the control schools + + align:start position:0% +compared to the control schools + + + align:start position:0% +compared to the control schools +we also see a clear difference for the + + align:start position:0% +we also see a clear difference for the + + + align:start position:0% +we also see a clear difference for the +treatment schools compared to both + + align:start position:0% +treatment schools compared to both + + + align:start position:0% +treatment schools compared to both +the control schools and the delayed + + align:start position:0% +the control schools and the delayed + + + align:start position:0% +the control schools and the delayed +treatment schools + + align:start position:0% +treatment schools + + + align:start position:0% +treatment schools +as well so that's fairly compelling + + align:start position:0% +as well so that's fairly compelling + + + align:start position:0% +as well so that's fairly compelling +compelling evidence that + + align:start position:0% +compelling evidence that + + + align:start position:0% +compelling evidence that +game or play in dictator games changes + + align:start position:0% + + + + align:start position:0% + +when students are exposed for quite a + + align:start position:0% +when students are exposed for quite a + + + align:start position:0% +when students are exposed for quite a +long time to poor kids in their + + align:start position:0% +long time to poor kids in their + + + align:start position:0% +long time to poor kids in their +classroom + + align:start position:0% +classroom + + + align:start position:0% +classroom +okay so now in addition um + + align:start position:0% +okay so now in addition um + + + align:start position:0% +okay so now in addition um +we will have a variation within a + + align:start position:0% +we will have a variation within a + + + align:start position:0% +we will have a variation within a +classroom so what i show you here this + + align:start position:0% +classroom so what i show you here this + + + align:start position:0% +classroom so what i show you here this +is all variation + + align:start position:0% +is all variation + + + align:start position:0% +is all variation +across classrooms that is to say if you + + align:start position:0% +across classrooms that is to say if you + + + align:start position:0% +across classrooms that is to say if you +have a poor kid in your classroom + + align:start position:0% +have a poor kid in your classroom + + + align:start position:0% +have a poor kid in your classroom +you will behave differently um or that + + align:start position:0% +you will behave differently um or that + + + align:start position:0% +you will behave differently um or that +will change your attitudes or you're + + align:start position:0% +will change your attitudes or you're + + + align:start position:0% +will change your attitudes or you're +giving in + + align:start position:0% +giving in + + + align:start position:0% +giving in +in dictator games uh towards + + align:start position:0% +in dictator games uh towards + + + align:start position:0% +in dictator games uh towards +the poor or other poor or children now + + align:start position:0% +the poor or other poor or children now + + + align:start position:0% +the poor or other poor or children now +in addition + + align:start position:0% +in addition + + + align:start position:0% +in addition +um the author also has um + + align:start position:0% +um the author also has um + + + align:start position:0% +um the author also has um +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +evidence of variation within classroom + + align:start position:0% +evidence of variation within classroom + + + align:start position:0% +evidence of variation within classroom +they let you think about for a second + + align:start position:0% +they let you think about for a second + + + align:start position:0% +they let you think about for a second +why is it important to also have + + align:start position:0% +why is it important to also have + + + align:start position:0% +why is it important to also have +variation within classroom + + align:start position:0% +variation within classroom + + + align:start position:0% +variation within classroom +isn't the evidence that we have here + + align:start position:0% +isn't the evidence that we have here + + + align:start position:0% +isn't the evidence that we have here +already compelling enough why do we need + + align:start position:0% +already compelling enough why do we need + + + align:start position:0% +already compelling enough why do we need +more + + align:start position:0% +more + + + align:start position:0% +more +and you think about this for a second + + align:start position:0% +and you think about this for a second + + + align:start position:0% +and you think about this for a second +the reason for that is that the diff and + + align:start position:0% +the reason for that is that the diff and + + + align:start position:0% +the reason for that is that the diff and +if the difference in differences + + align:start position:0% +if the difference in differences + + + align:start position:0% +if the difference in differences +comparing essentially across + + align:start position:0% +comparing essentially across + + + align:start position:0% +comparing essentially across +classrooms identifies the overall effect + + align:start position:0% +classrooms identifies the overall effect + + + align:start position:0% +classrooms identifies the overall effect +of having poor classmates in class + + align:start position:0% +of having poor classmates in class + + + align:start position:0% +of having poor classmates in class +that might be the result of like + + align:start position:0% +that might be the result of like + + + align:start position:0% +that might be the result of like +personal interactions + + align:start position:0% +personal interactions + + + align:start position:0% +personal interactions +but it might also be the result of like + + align:start position:0% +but it might also be the result of like + + + align:start position:0% +but it might also be the result of like +the teacher uh the curriculum might + + align:start position:0% +the teacher uh the curriculum might + + + align:start position:0% +the teacher uh the curriculum might +change your parents might change + + align:start position:0% +change your parents might change + + + align:start position:0% +change your parents might change +in some ways and just telling you like + + align:start position:0% +in some ways and just telling you like + + + align:start position:0% +in some ways and just telling you like +look there's these poor kids in your + + align:start position:0% +look there's these poor kids in your + + + align:start position:0% +look there's these poor kids in your +class + + align:start position:0% +class + + + align:start position:0% +class +the teachers might tell everybody oh you + + align:start position:0% +the teachers might tell everybody oh you + + + align:start position:0% +the teachers might tell everybody oh you +need to be nice to poor kids + + align:start position:0% +need to be nice to poor kids + + + align:start position:0% +need to be nice to poor kids +the curriculum might change it might + + align:start position:0% +the curriculum might change it might + + + align:start position:0% +the curriculum might change it might +sort of include things that tell you to + + align:start position:0% +sort of include things that tell you to + + + align:start position:0% +sort of include things that tell you to +be nice to poor kids and so on you might + + align:start position:0% +be nice to poor kids and so on you might + + + align:start position:0% +be nice to poor kids and so on you might +be sort of exposed to just different + + align:start position:0% +be sort of exposed to just different + + + align:start position:0% +be sort of exposed to just different +types of material + + align:start position:0% +types of material + + + align:start position:0% +types of material +so really given the evidence that we + + align:start position:0% +so really given the evidence that we + + + align:start position:0% +so really given the evidence that we +have here when you just compare across + + align:start position:0% +have here when you just compare across + + + align:start position:0% +have here when you just compare across +classrooms + + align:start position:0% +classrooms + + + align:start position:0% +classrooms +you cannot disentangle whether this is + + align:start position:0% +you cannot disentangle whether this is + + + align:start position:0% +you cannot disentangle whether this is +driven from like + + align:start position:0% +driven from like + + + align:start position:0% +driven from like +being personally um exposed in terms of + + align:start position:0% +being personally um exposed in terms of + + + align:start position:0% +being personally um exposed in terms of +interacting with poor children + + align:start position:0% +interacting with poor children + + + align:start position:0% +interacting with poor children +personally by just talking to them in + + align:start position:0% +personally by just talking to them in + + + align:start position:0% +personally by just talking to them in +certain ways and being exposed to them + + align:start position:0% +certain ways and being exposed to them + + + align:start position:0% +certain ways and being exposed to them +and like + + align:start position:0% +and like + + + align:start position:0% +and like +learning about them and so on so it + + align:start position:0% +learning about them and so on so it + + + align:start position:0% +learning about them and so on so it +cannot disentangle personal interactions + + align:start position:0% +cannot disentangle personal interactions + + + align:start position:0% +cannot disentangle personal interactions +from teacher curriculum changes that are + + align:start position:0% +from teacher curriculum changes that are + + + align:start position:0% +from teacher curriculum changes that are +essentially at the classroom level + + align:start position:0% +essentially at the classroom level + + + align:start position:0% +essentially at the classroom level +so in addition then gautam also has + + align:start position:0% +so in addition then gautam also has + + + align:start position:0% +so in addition then gautam also has +within classroom within classroom + + align:start position:0% +within classroom within classroom + + + align:start position:0% +within classroom within classroom +strategy + + align:start position:0% +strategy + + + align:start position:0% +strategy +that uh exploits the assignment to study + + align:start position:0% +that uh exploits the assignment to study + + + align:start position:0% +that uh exploits the assignment to study +groups + + align:start position:0% +groups + + + align:start position:0% +groups +what is that doing is essentially it + + align:start position:0% +what is that doing is essentially it + + + align:start position:0% +what is that doing is essentially it +isolates the role of direct + + align:start position:0% +isolates the role of direct + + + align:start position:0% +isolates the role of direct +personal interactions and is not subject + + align:start position:0% +personal interactions and is not subject + + + align:start position:0% +personal interactions and is not subject +to sorting concerns another concern + + align:start position:0% +to sorting concerns another concern + + + align:start position:0% +to sorting concerns another concern +might be that + + align:start position:0% +might be that + + + align:start position:0% +might be that +you know you might sort of say oh oh in + + align:start position:0% +you know you might sort of say oh oh in + + + align:start position:0% +you know you might sort of say oh oh in +this school + + align:start position:0% +this school + + + align:start position:0% +this school +uh uh uh they're having like poor kids + + align:start position:0% +uh uh uh they're having like poor kids + + + align:start position:0% +uh uh uh they're having like poor kids +that + + align:start position:0% +that + + + align:start position:0% +that +um uh that are led into this private + + align:start position:0% +um uh that are led into this private + + + align:start position:0% +um uh that are led into this private +school + + align:start position:0% +school + + + align:start position:0% +school +i'm gonna send my kids to somebody else + + align:start position:0% +i'm gonna send my kids to somebody else + + + align:start position:0% +i'm gonna send my kids to somebody else +so that's also an issue + + align:start position:0% +so that's also an issue + + + align:start position:0% +so that's also an issue +perhaps potentially in the uh uh + + align:start position:0% +perhaps potentially in the uh uh + + + align:start position:0% +perhaps potentially in the uh uh +in the evidence that i showed you before + + align:start position:0% +in the evidence that i showed you before + + + align:start position:0% +in the evidence that i showed you before +across classrooms that within classroom + + align:start position:0% +across classrooms that within classroom + + + align:start position:0% +across classrooms that within classroom +strategy is now looking at + + align:start position:0% +strategy is now looking at + + + align:start position:0% +strategy is now looking at +everybody who's in that classroom and + + align:start position:0% +everybody who's in that classroom and + + + align:start position:0% +everybody who's in that classroom and +looking at some kids where they're just + + align:start position:0% +looking at some kids where they're just + + + align:start position:0% +looking at some kids where they're just +randomly assigned to be in study groups + + align:start position:0% +randomly assigned to be in study groups + + + align:start position:0% +randomly assigned to be in study groups +with poor kids and others were not + + align:start position:0% +with poor kids and others were not + + + align:start position:0% +with poor kids and others were not +and that sort of allows to disentangle + + align:start position:0% +and that sort of allows to disentangle + + + align:start position:0% +and that sort of allows to disentangle +or allow us to isolate the + + align:start position:0% +or allow us to isolate the + + + align:start position:0% +or allow us to isolate the +effect of personal interactions so one + + align:start position:0% +effect of personal interactions so one + + + align:start position:0% +effect of personal interactions so one +hour a day + + align:start position:0% +hour a day + + + align:start position:0% +hour a day +um kids were working in small groups of + + align:start position:0% +um kids were working in small groups of + + + align:start position:0% +um kids were working in small groups of +two to four students + + align:start position:0% +two to four students + + + align:start position:0% +two to four students +remember this is for a very long period + + align:start position:0% +remember this is for a very long period + + + align:start position:0% +remember this is for a very long period +of time so like you know + + align:start position:0% +of time so like you know + + + align:start position:0% +of time so like you know +um it's one hour per day but it was also + + align:start position:0% +um it's one hour per day but it was also + + + align:start position:0% +um it's one hour per day but it was also +like for quite a bit of time it's not + + align:start position:0% +like for quite a bit of time it's not + + + align:start position:0% +like for quite a bit of time it's not +just like doing that once or twice it's + + align:start position:0% +just like doing that once or twice it's + + + align:start position:0% +just like doing that once or twice it's +for like an extended period of time + + align:start position:0% +for like an extended period of time + + + align:start position:0% +for like an extended period of time +and crucially some schools use the + + align:start position:0% +and crucially some schools use the + + + align:start position:0% +and crucially some schools use the +alphabetic order of first names to + + align:start position:0% +alphabetic order of first names to + + + align:start position:0% +alphabetic order of first names to +assign + + align:start position:0% +assign + + + align:start position:0% +assign +study groups so that's essentially + + align:start position:0% +study groups so that's essentially + + + align:start position:0% +study groups so that's essentially +exogenous variation in personal + + align:start position:0% +exogenous variation in personal + + + align:start position:0% +exogenous variation in personal +interactions + + align:start position:0% +interactions + + + align:start position:0% +interactions +other schools frequently um + + align:start position:0% +other schools frequently um + + + align:start position:0% +other schools frequently um +shuffled the groups and only um which + + align:start position:0% +shuffled the groups and only um which + + + align:start position:0% +shuffled the groups and only um which +essentially + + align:start position:0% +essentially + + + align:start position:0% +essentially +sort of uh everybody was equally exposed + + align:start position:0% +sort of uh everybody was equally exposed + + + align:start position:0% +sort of uh everybody was equally exposed +to those kinds of + + align:start position:0% +to those kinds of + + + align:start position:0% +to those kinds of +uh uh to two different students to your + + align:start position:0% +uh uh to two different students to your + + + align:start position:0% +uh uh to two different students to your +sometimes in study groups with + + align:start position:0% +sometimes in study groups with + + + align:start position:0% +sometimes in study groups with +rich students only and sometimes for + + align:start position:0% +rich students only and sometimes for + + + align:start position:0% +rich students only and sometimes for +poor students only + + align:start position:0% +poor students only + + + align:start position:0% +poor students only +in the first group where the alphabetic + + align:start position:0% +in the first group where the alphabetic + + + align:start position:0% +in the first group where the alphabetic +order was used + + align:start position:0% +order was used + + + align:start position:0% +order was used +you were either sort of in the study + + align:start position:0% +you were either sort of in the study + + + align:start position:0% +you were either sort of in the study +group where you happened to be + + align:start position:0% +group where you happened to be + + + align:start position:0% +group where you happened to be +next to somebody um + + align:start position:0% +next to somebody um + + + align:start position:0% +next to somebody um +uh uh who's a poor kid because they + + align:start position:0% +uh uh who's a poor kid because they + + + align:start position:0% +uh uh who's a poor kid because they +happen to be next to you in the alphabet + + align:start position:0% +happen to be next to you in the alphabet + + + align:start position:0% +happen to be next to you in the alphabet +or you're not and that stayed the same + + align:start position:0% +or you're not and that stayed the same + + + align:start position:0% +or you're not and that stayed the same +now + + align:start position:0% +now + + + align:start position:0% +now +what does this let us look at + + align:start position:0% +what does this let us look at + + + align:start position:0% +what does this let us look at +essentially the alphabetic order + + align:start position:0% +essentially the alphabetic order + + + align:start position:0% +essentially the alphabetic order +predicts + + align:start position:0% +predicts + + + align:start position:0% +predicts +um study partners so now you might say + + align:start position:0% +um study partners so now you might say + + + align:start position:0% +um study partners so now you might say +people with different names might also + + align:start position:0% +people with different names might also + + + align:start position:0% +people with different names might also +be different so it could just be that + + align:start position:0% +be different so it could just be that + + + align:start position:0% +be different so it could just be that +like my name + + align:start position:0% +like my name + + + align:start position:0% +like my name +because my name is different i'm more + + align:start position:0% +because my name is different i'm more + + + align:start position:0% +because my name is different i'm more +likely to be + + align:start position:0% +likely to be + + + align:start position:0% +likely to be +next in the alphabet to a poor student + + align:start position:0% +next in the alphabet to a poor student + + + align:start position:0% +next in the alphabet to a poor student +for example if i'm a rich kid and + + align:start position:0% +for example if i'm a rich kid and + + + align:start position:0% +for example if i'm a rich kid and +there's some + + align:start position:0% +there's some + + + align:start position:0% +there's some +names that are like more similar to poor + + align:start position:0% +names that are like more similar to poor + + + align:start position:0% +names that are like more similar to poor +kids names + + align:start position:0% +kids names + + + align:start position:0% +kids names +it could be that my parents are + + align:start position:0% +it could be that my parents are + + + align:start position:0% +it could be that my parents are +particularly tolerant they also gave me + + align:start position:0% +particularly tolerant they also gave me + + + align:start position:0% +particularly tolerant they also gave me +a name that + + align:start position:0% +a name that + + + align:start position:0% +a name that +sounds like a poor person and therefore + + align:start position:0% +sounds like a poor person and therefore + + + align:start position:0% +sounds like a poor person and therefore +i'm more likely to be in a study group + + align:start position:0% +i'm more likely to be in a study group + + + align:start position:0% +i'm more likely to be in a study group +with a poor + + align:start position:0% +with a poor + + + align:start position:0% +with a poor +other poor kid it's not and that's not + + align:start position:0% +other poor kid it's not and that's not + + + align:start position:0% +other poor kid it's not and that's not +then the impact of being in the study + + align:start position:0% +then the impact of being in the study + + + align:start position:0% +then the impact of being in the study +group but rather sort of selection just + + align:start position:0% +group but rather sort of selection just + + + align:start position:0% +group but rather sort of selection just +could be that + + align:start position:0% +could be that + + + align:start position:0% +could be that +names are different or people with + + align:start position:0% +names are different or people with + + + align:start position:0% +names are different or people with +different names are different so that's + + align:start position:0% +different names are different so that's + + + align:start position:0% +different names are different so that's +why having this control group is really + + align:start position:0% +why having this control group is really + + + align:start position:0% +why having this control group is really +nice + + align:start position:0% +nice + + + align:start position:0% +nice +so what we can look at now is to say we + + align:start position:0% +so what we can look at now is to say we + + + align:start position:0% +so what we can look at now is to say we +can look at + + align:start position:0% + + + + align:start position:0% + +kids that have names adjacent to rich + + align:start position:0% +kids that have names adjacent to rich + + + align:start position:0% +kids that have names adjacent to rich +students and kids that have names + + align:start position:0% +students and kids that have names + + + align:start position:0% +students and kids that have names +adjacent to + + align:start position:0% +adjacent to + + + align:start position:0% +adjacent to +poor students so if you look at the left + + align:start position:0% +poor students so if you look at the left + + + align:start position:0% +poor students so if you look at the left +side is essentially looking at + + align:start position:0% +side is essentially looking at + + + align:start position:0% +side is essentially looking at +students that have their names adjacent + + align:start position:0% +students that have their names adjacent + + + align:start position:0% +students that have their names adjacent +to + + align:start position:0% +to + + + align:start position:0% +to +rich students only or students that have + + align:start position:0% +rich students only or students that have + + + align:start position:0% +rich students only or students that have +names adjacent to also some poor + + align:start position:0% +names adjacent to also some poor + + + align:start position:0% +names adjacent to also some poor +students + + align:start position:0% +students + + + align:start position:0% +students +when you look at that where the + + align:start position:0% +when you look at that where the + + + align:start position:0% +when you look at that where the +alphabetic order was not used + + align:start position:0% +alphabetic order was not used + + + align:start position:0% +alphabetic order was not used +the outcome here is now what's your + + align:start position:0% +the outcome here is now what's your + + + align:start position:0% +the outcome here is now what's your +share of having poor study partners and + + align:start position:0% +share of having poor study partners and + + + align:start position:0% +share of having poor study partners and +so there essentially there's no + + align:start position:0% +so there essentially there's no + + + align:start position:0% +so there essentially there's no +difference + + align:start position:0% +difference + + + align:start position:0% +difference +as it should be because the alphabetic + + align:start position:0% +as it should be because the alphabetic + + + align:start position:0% +as it should be because the alphabetic +order was not used they were just + + align:start position:0% +order was not used they were just + + + align:start position:0% +order was not used they were just +shuffling around + + align:start position:0% +shuffling around + + + align:start position:0% +shuffling around +the kids all the time so it didn't + + align:start position:0% +the kids all the time so it didn't + + + align:start position:0% +the kids all the time so it didn't +really matter what your alphabet was it + + align:start position:0% +really matter what your alphabet was it + + + align:start position:0% +really matter what your alphabet was it +didn't really matter but + + align:start position:0% +didn't really matter but + + + align:start position:0% +didn't really matter but +but crucially we can still look at the + + align:start position:0% +but crucially we can still look at the + + + align:start position:0% +but crucially we can still look at the +alphabet we can look at + + align:start position:0% +alphabet we can look at + + + align:start position:0% +alphabet we can look at +kids that have names where adjacent in + + align:start position:0% +kids that have names where adjacent in + + + align:start position:0% +kids that have names where adjacent in +the alphabet there's only + + align:start position:0% +the alphabet there's only + + + align:start position:0% +the alphabet there's only +rich kids rich students or we can look + + align:start position:0% +rich kids rich students or we can look + + + align:start position:0% +rich kids rich students or we can look +at + + align:start position:0% +at + + + align:start position:0% +at +kids that have names where adjacent to + + align:start position:0% +kids that have names where adjacent to + + + align:start position:0% +kids that have names where adjacent to +the alphabets they're poor students + + align:start position:0% +the alphabets they're poor students + + + align:start position:0% +the alphabets they're poor students +and here you see on the left side of the + + align:start position:0% +and here you see on the left side of the + + + align:start position:0% +and here you see on the left side of the +graph you see essentially no difference + + align:start position:0% +graph you see essentially no difference + + + align:start position:0% +graph you see essentially no difference +across these + + align:start position:0% +across these + + + align:start position:0% +across these +groups so they were equally likely to + + align:start position:0% +groups so they were equally likely to + + + align:start position:0% +groups so they were equally likely to +have a poor kid in their study group + + align:start position:0% +have a poor kid in their study group + + + align:start position:0% +have a poor kid in their study group +in contrast on the right side of the + + align:start position:0% +in contrast on the right side of the + + + align:start position:0% +in contrast on the right side of the +graph you see + + align:start position:0% +graph you see + + + align:start position:0% +graph you see +the alphabetic order was used to assign + + align:start position:0% +the alphabetic order was used to assign + + + align:start position:0% +the alphabetic order was used to assign +study groups so if you had a name + + align:start position:0% +study groups so if you had a name + + + align:start position:0% +study groups so if you had a name +adjacent + + align:start position:0% +adjacent + + + align:start position:0% +adjacent +to a poor student in the alphabet you're + + align:start position:0% +to a poor student in the alphabet you're + + + align:start position:0% +to a poor student in the alphabet you're +very very likely to have a poor kid + + align:start position:0% +very very likely to have a poor kid + + + align:start position:0% +very very likely to have a poor kid +assigned to you or be in your study + + align:start position:0% +assigned to you or be in your study + + + align:start position:0% +assigned to you or be in your study +group not always because you know + + align:start position:0% +group not always because you know + + + align:start position:0% +group not always because you know +sometimes these are groups of three so + + align:start position:0% +sometimes these are groups of three so + + + align:start position:0% +sometimes these are groups of three so +that sometimes you were + + align:start position:0% +that sometimes you were + + + align:start position:0% +that sometimes you were +lucky or unlucky depending on how you + + align:start position:0% +lucky or unlucky depending on how you + + + align:start position:0% +lucky or unlucky depending on how you +view it there were just sort of the + + align:start position:0% +view it there were just sort of the + + + align:start position:0% +view it there were just sort of the +group was like just above you or below + + align:start position:0% +group was like just above you or below + + + align:start position:0% +group was like just above you or below +you in the alphabet + + align:start position:0% +you in the alphabet + + + align:start position:0% +you in the alphabet +but most of the time if you have a name + + align:start position:0% +but most of the time if you have a name + + + align:start position:0% +but most of the time if you have a name +adjacent to approach student that + + align:start position:0% +adjacent to approach student that + + + align:start position:0% +adjacent to approach student that +student or any + + align:start position:0% +student or any + + + align:start position:0% +student or any +uh any poor student would be in your + + align:start position:0% +uh any poor student would be in your + + + align:start position:0% +uh any poor student would be in your +study group + + align:start position:0% +study group + + + align:start position:0% +study group +uh if you didn't have a name adjacent to + + align:start position:0% +uh if you didn't have a name adjacent to + + + align:start position:0% +uh if you didn't have a name adjacent to +you um + + align:start position:0% +you um + + + align:start position:0% +you um +or if you only had like rich student + + align:start position:0% +or if you only had like rich student + + + align:start position:0% +or if you only had like rich student +adjacent to you there's still a chance + + align:start position:0% +adjacent to you there's still a chance + + + align:start position:0% +adjacent to you there's still a chance +that you have a poor student in your + + align:start position:0% +that you have a poor student in your + + + align:start position:0% +that you have a poor student in your +study group because this could be just + + align:start position:0% +study group because this could be just + + + align:start position:0% +study group because this could be just +like you know not the person next to you + + align:start position:0% +like you know not the person next to you + + + align:start position:0% +like you know not the person next to you +but the person + + align:start position:0% +but the person + + + align:start position:0% +but the person +another person further down is in fact a + + align:start position:0% +another person further down is in fact a + + + align:start position:0% +another person further down is in fact a +poor student you end up in that group + + align:start position:0% +poor student you end up in that group + + + align:start position:0% +poor student you end up in that group +without + + align:start position:0% +without + + + align:start position:0% +without +that student remember these are groups + + align:start position:0% +that student remember these are groups + + + align:start position:0% +that student remember these are groups +of two to four students + + align:start position:0% +of two to four students + + + align:start position:0% +of two to four students +so it could just be that you're in a + + align:start position:0% +so it could just be that you're in a + + + align:start position:0% +so it could just be that you're in a +group of three to four student and not + + align:start position:0% +group of three to four student and not + + + align:start position:0% +group of three to four student and not +the person adjacent to you but the + + align:start position:0% +the person adjacent to you but the + + + align:start position:0% +the person adjacent to you but the +person after that + + align:start position:0% +person after that + + + align:start position:0% +person after that +ends up in your study group so you're + + align:start position:0% +ends up in your study group so you're + + + align:start position:0% +ends up in your study group so you're +still likely to have + + align:start position:0% +still likely to have + + + align:start position:0% +still likely to have +um or you know you have still like about + + align:start position:0% +um or you know you have still like about + + + align:start position:0% +um or you know you have still like about +like a 40 + + align:start position:0% +like a 40 + + + align:start position:0% +like a 40 +chance of having a poor kid in your um + + align:start position:0% +chance of having a poor kid in your um + + + align:start position:0% +chance of having a poor kid in your um +in your study group but there's a huge + + align:start position:0% +in your study group but there's a huge + + + align:start position:0% +in your study group but there's a huge +difference between the two types of + + align:start position:0% +difference between the two types of + + + align:start position:0% +difference between the two types of +groups + + align:start position:0% +groups + + + align:start position:0% +groups +um the name adjacent to the study group + + align:start position:0% +um the name adjacent to the study group + + + align:start position:0% +um the name adjacent to the study group +has like huge fraction about 90 + + align:start position:0% +has like huge fraction about 90 + + + align:start position:0% +has like huge fraction about 90 +or uh versus 40 so crucially now we can + + align:start position:0% +or uh versus 40 so crucially now we can + + + align:start position:0% +or uh versus 40 so crucially now we can +compare + + align:start position:0% +compare + + + align:start position:0% +compare +for both types of schools for the + + align:start position:0% +for both types of schools for the + + + align:start position:0% +for both types of schools for the +schools on the right-hand side + + align:start position:0% +schools on the right-hand side + + + align:start position:0% +schools on the right-hand side +where essentially the names are very + + align:start position:0% +where essentially the names are very + + + align:start position:0% +where essentially the names are very +predictive of + + align:start position:0% +predictive of + + + align:start position:0% +predictive of +of having a poorest kid in uh in your + + align:start position:0% +of having a poorest kid in uh in your + + + align:start position:0% +of having a poorest kid in uh in your +study group + + align:start position:0% +study group + + + align:start position:0% +study group +versus on the left-hand side where the + + align:start position:0% +versus on the left-hand side where the + + + align:start position:0% +versus on the left-hand side where the +names are not predictive at all whether + + align:start position:0% +names are not predictive at all whether + + + align:start position:0% +names are not predictive at all whether +um you have a a poor kid in your study + + align:start position:0% +um you have a a poor kid in your study + + + align:start position:0% +um you have a a poor kid in your study +group + + align:start position:0% +group + + + align:start position:0% +group +and so we can like that way we can keep + + align:start position:0% +and so we can like that way we can keep + + + align:start position:0% +and so we can like that way we can keep +selection the same the types of name are + + align:start position:0% +selection the same the types of name are + + + align:start position:0% +selection the same the types of name are +the same + + align:start position:0% +the same + + + align:start position:0% +the same +we are isolating the impact of having a + + align:start position:0% +we are isolating the impact of having a + + + align:start position:0% +we are isolating the impact of having a +poor kid + + align:start position:0% +poor kid + + + align:start position:0% +poor kid +in your study group now what does the + + align:start position:0% +in your study group now what does the + + + align:start position:0% +in your study group now what does the +author find he finds that + + align:start position:0% +author find he finds that + + + align:start position:0% +author find he finds that +this is what we showed you before which + + align:start position:0% +this is what we showed you before which + + + align:start position:0% +this is what we showed you before which +is about you know + + align:start position:0% +is about you know + + + align:start position:0% +is about you know +in the control group we had about uh in + + align:start position:0% +in the control group we had about uh in + + + align:start position:0% +in the control group we had about uh in +the dictator game + + align:start position:0% +the dictator game + + + align:start position:0% +the dictator game +these kids gave about 27 um + + align:start position:0% +these kids gave about 27 um + + + align:start position:0% +these kids gave about 27 um +uh 27 percent uh being having a poor kid + + align:start position:0% +uh 27 percent uh being having a poor kid + + + align:start position:0% +uh 27 percent uh being having a poor kid +in your classroom that's the evidence + + align:start position:0% +in your classroom that's the evidence + + + align:start position:0% +in your classroom that's the evidence +that i already showed you the treatment + + align:start position:0% +that i already showed you the treatment + + + align:start position:0% +that i already showed you the treatment +effect is about + + align:start position:0% +effect is about + + + align:start position:0% +effect is about +uh uh 12 percentage points that's fairly + + align:start position:0% +uh uh 12 percentage points that's fairly + + + align:start position:0% +uh uh 12 percentage points that's fairly +large that's almost like a 50 + + align:start position:0% +large that's almost like a 50 + + + align:start position:0% +large that's almost like a 50 +a 50 increase a little bit less than + + align:start position:0% +a 50 increase a little bit less than + + + align:start position:0% +a 50 increase a little bit less than +that so that's a huge + + align:start position:0% +that so that's a huge + + + align:start position:0% +that so that's a huge +increase and then in addition um when + + align:start position:0% +increase and then in addition um when + + + align:start position:0% +increase and then in addition um when +you look at + + align:start position:0% +you look at + + + align:start position:0% +you look at +kids that have a poor study partner + + align:start position:0% +kids that have a poor study partner + + + align:start position:0% +kids that have a poor study partner +notice that these are things not + + align:start position:0% +notice that these are things not + + + align:start position:0% +notice that these are things not +necessarily additive but you have a poor + + align:start position:0% +necessarily additive but you have a poor + + + align:start position:0% +necessarily additive but you have a poor +study partner versus not + + align:start position:0% +study partner versus not + + + align:start position:0% +study partner versus not +there's an effect of about 7.5 + + align:start position:0% +there's an effect of about 7.5 + + + align:start position:0% +there's an effect of about 7.5 +percentage points + + align:start position:0% +percentage points + + + align:start position:0% +percentage points +that's a pretty large effect so + + align:start position:0% +that's a pretty large effect so + + + align:start position:0% +that's a pretty large effect so +both of these things seem to matter + + align:start position:0% +both of these things seem to matter + + + align:start position:0% +both of these things seem to matter +personal interactions seem to be quite + + align:start position:0% +personal interactions seem to be quite + + + align:start position:0% +personal interactions seem to be quite +important + + align:start position:0% +important + + + align:start position:0% +important +but in addition there seem to be also + + align:start position:0% +but in addition there seem to be also + + + align:start position:0% +but in addition there seem to be also +some additional effects perhaps coming + + align:start position:0% +some additional effects perhaps coming + + + align:start position:0% +some additional effects perhaps coming +from the + + align:start position:0% +from the + + + align:start position:0% +from the +classroom level you might so there's two + + align:start position:0% +classroom level you might so there's two + + + align:start position:0% +classroom level you might so there's two +types of effects that are possible here + + align:start position:0% +types of effects that are possible here + + + align:start position:0% +types of effects that are possible here +some types of effects could be from the + + align:start position:0% +some types of effects could be from the + + + align:start position:0% +some types of effects could be from the +teacher parents curriculum etc might be + + align:start position:0% +teacher parents curriculum etc might be + + + align:start position:0% +teacher parents curriculum etc might be +different + + align:start position:0% +different + + + align:start position:0% +different +or other things could be just like even + + align:start position:0% +or other things could be just like even + + + align:start position:0% +or other things could be just like even +if you don't have a poor kid in your + + align:start position:0% +if you don't have a poor kid in your + + + align:start position:0% +if you don't have a poor kid in your +study group you might still play with + + align:start position:0% +study group you might still play with + + + align:start position:0% +study group you might still play with +them or be friends with them or just + + align:start position:0% +them or be friends with them or just + + + align:start position:0% +them or be friends with them or just +seeing them around a new classroom + + align:start position:0% +seeing them around a new classroom + + + align:start position:0% +seeing them around a new classroom +might affect you but crucially crucially + + align:start position:0% +might affect you but crucially crucially + + + align:start position:0% +might affect you but crucially crucially +the + + align:start position:0% +the + + + align:start position:0% +the +personal interactions seem to be very + + align:start position:0% +personal interactions seem to be very + + + align:start position:0% +personal interactions seem to be very +important + + align:start position:0% +important + + + align:start position:0% +important +as well now one question you might ask + + align:start position:0% +as well now one question you might ask + + + align:start position:0% +as well now one question you might ask +as well so far i showed you generosity + + align:start position:0% +as well so far i showed you generosity + + + align:start position:0% +as well so far i showed you generosity +towards + + align:start position:0% +towards + + + align:start position:0% +towards +poor children right so that was game + + align:start position:0% +poor children right so that was game + + + align:start position:0% +poor children right so that was game +number one we looked at + + align:start position:0% +number one we looked at + + + align:start position:0% +number one we looked at +what happens in the dictator games when + + align:start position:0% +what happens in the dictator games when + + + align:start position:0% +what happens in the dictator games when +a rich kid + + align:start position:0% +a rich kid + + + align:start position:0% +a rich kid +plays with a poor kid and the rich kids + + align:start position:0% +plays with a poor kid and the rich kids + + + align:start position:0% +plays with a poor kid and the rich kids +become nicer towards the + + align:start position:0% +become nicer towards the + + + align:start position:0% +become nicer towards the +poor kids now how about generosity + + align:start position:0% +poor kids now how about generosity + + + align:start position:0% +poor kids now how about generosity +towards + + align:start position:0% +towards + + + align:start position:0% +towards +other wealthy children well it turns out + + align:start position:0% +other wealthy children well it turns out + + + align:start position:0% +other wealthy children well it turns out +that that that increases as well + + align:start position:0% +that that that increases as well + + + align:start position:0% +that that that increases as well +there's a smaller effect size but it's + + align:start position:0% +there's a smaller effect size but it's + + + align:start position:0% +there's a smaller effect size but it's +still substantial and in fact um + + align:start position:0% +still substantial and in fact um + + + align:start position:0% +still substantial and in fact um +statistically uh significant + + align:start position:0% +statistically uh significant + + + align:start position:0% +statistically uh significant +so why might that be you might sort of + + align:start position:0% +so why might that be you might sort of + + + align:start position:0% +so why might that be you might sort of +ask well what's going on here + + align:start position:0% +ask well what's going on here + + + align:start position:0% +ask well what's going on here +so here's the the evidence you sort of + + align:start position:0% +so here's the the evidence you sort of + + + align:start position:0% +so here's the the evidence you sort of +see the + + align:start position:0% +see the + + + align:start position:0% +see the +changing giving to rich participants + + align:start position:0% +changing giving to rich participants + + + align:start position:0% +changing giving to rich participants +this is sort of like a distribution you + + align:start position:0% +this is sort of like a distribution you + + + align:start position:0% +this is sort of like a distribution you +see + + align:start position:0% +see + + + align:start position:0% +see +this is the share giving to the rich + + align:start position:0% +this is the share giving to the rich + + + align:start position:0% +this is the share giving to the rich +participant it seems to be what happens + + align:start position:0% +participant it seems to be what happens + + + align:start position:0% +participant it seems to be what happens +these are essentially the fraction of + + align:start position:0% +these are essentially the fraction of + + + align:start position:0% +these are essentially the fraction of +students in the different treatment + + align:start position:0% +students in the different treatment + + + align:start position:0% +students in the different treatment +versus control + + align:start position:0% +versus control + + + align:start position:0% +versus control +who gives 0 10 20 30 40 50 percent + + align:start position:0% +who gives 0 10 20 30 40 50 percent + + + align:start position:0% +who gives 0 10 20 30 40 50 percent +and what you see there's about a 10 um + + align:start position:0% +and what you see there's about a 10 um + + + align:start position:0% +and what you see there's about a 10 um +percentage points + + align:start position:0% +percentage points + + + align:start position:0% +percentage points +decrease in the fraction who gives zero + + align:start position:0% +decrease in the fraction who gives zero + + + align:start position:0% +decrease in the fraction who gives zero +and about uh eight something uh + + align:start position:0% +and about uh eight something uh + + + align:start position:0% +and about uh eight something uh +percentage points increase in the + + align:start position:0% +percentage points increase in the + + + align:start position:0% +percentage points increase in the +fraction who give + + align:start position:0% +fraction who give + + + align:start position:0% +fraction who give +fifty percent so it seems to be that + + align:start position:0% +fifty percent so it seems to be that + + + align:start position:0% +fifty percent so it seems to be that +there's quite a few students + + align:start position:0% +there's quite a few students + + + align:start position:0% +there's quite a few students +who move from zero um percent about like + + align:start position:0% +who move from zero um percent about like + + + align:start position:0% +who move from zero um percent about like +you know ten percent of them move from + + align:start position:0% +you know ten percent of them move from + + + align:start position:0% +you know ten percent of them move from +zero percent + + align:start position:0% +zero percent + + + align:start position:0% +zero percent +to um uh 50 and 50 50 is kind of like + + align:start position:0% +to um uh 50 and 50 50 is kind of like + + + align:start position:0% +to um uh 50 and 50 50 is kind of like +the equal + + align:start position:0% +the equal + + + align:start position:0% +the equal +allocation so rich kids are also + + align:start position:0% +allocation so rich kids are also + + + align:start position:0% +allocation so rich kids are also +becoming nicer towards + + align:start position:0% +becoming nicer towards + + + align:start position:0% +becoming nicer towards +rich kids in these dictator games so + + align:start position:0% +rich kids in these dictator games so + + + align:start position:0% +rich kids in these dictator games so +what's going on here + + align:start position:0% +what's going on here + + + align:start position:0% +what's going on here +um there's different potential + + align:start position:0% +um there's different potential + + + align:start position:0% +um there's different potential +explanations perhaps the most + + align:start position:0% +explanations perhaps the most + + + align:start position:0% +explanations perhaps the most +plausible explanation the study you know + + align:start position:0% +plausible explanation the study you know + + + align:start position:0% +plausible explanation the study you know +has some evidence on that + + align:start position:0% +has some evidence on that + + + align:start position:0% +has some evidence on that +um at the end of the day it's hard to + + align:start position:0% +um at the end of the day it's hard to + + + align:start position:0% +um at the end of the day it's hard to +sort of entirely nail this or like you + + align:start position:0% +sort of entirely nail this or like you + + + align:start position:0% +sort of entirely nail this or like you +know + + align:start position:0% +know + + + align:start position:0% +know +rule out all other potential explanation + + align:start position:0% +rule out all other potential explanation + + + align:start position:0% +rule out all other potential explanation +but it's quite + + align:start position:0% +but it's quite + + + align:start position:0% +but it's quite +plausible that what's happening here is + + align:start position:0% +plausible that what's happening here is + + + align:start position:0% +plausible that what's happening here is +that like inequity + + align:start position:0% +that like inequity + + + align:start position:0% +that like inequity +students when you're exposed to poor + + align:start position:0% +students when you're exposed to poor + + + align:start position:0% +students when you're exposed to poor +children you're essentially + + align:start position:0% +children you're essentially + + + align:start position:0% +children you're essentially +um more averse to like inequality + + align:start position:0% +um more averse to like inequality + + + align:start position:0% +um more averse to like inequality +or inequity across people + + align:start position:0% +or inequity across people + + + align:start position:0% +or inequity across people +even in things in fairly trivial things + + align:start position:0% +even in things in fairly trivial things + + + align:start position:0% +even in things in fairly trivial things +that are such as + + align:start position:0% +that are such as + + + align:start position:0% +that are such as +dictator games now i told you before + + align:start position:0% +dictator games now i told you before + + + align:start position:0% +dictator games now i told you before +that's a little bit + + align:start position:0% +that's a little bit + + + align:start position:0% +that's a little bit +funny because dictator games obviously + + align:start position:0% +funny because dictator games obviously + + + align:start position:0% +funny because dictator games obviously +are very narrowly framing people and + + align:start position:0% +are very narrowly framing people and + + + align:start position:0% +are very narrowly framing people and +looking at essentially + + align:start position:0% +looking at essentially + + + align:start position:0% +looking at essentially +when very narrow outcomes um + + align:start position:0% +when very narrow outcomes um + + + align:start position:0% +when very narrow outcomes um +if we have like a 50 50 outcome in the + + align:start position:0% +if we have like a 50 50 outcome in the + + + align:start position:0% +if we have like a 50 50 outcome in the +dictator game that doesn't mean that our + + align:start position:0% +dictator game that doesn't mean that our + + + align:start position:0% +dictator game that doesn't mean that our +life is + + align:start position:0% +life is + + + align:start position:0% +life is +uh the same it might be you might be + + align:start position:0% +uh the same it might be you might be + + + align:start position:0% +uh the same it might be you might be +still much richer than i am + + align:start position:0% +still much richer than i am + + + align:start position:0% +still much richer than i am +so um having sort of equal outcomes in + + align:start position:0% +so um having sort of equal outcomes in + + + align:start position:0% +so um having sort of equal outcomes in +the dictator game 50 50 allocation in + + align:start position:0% +the dictator game 50 50 allocation in + + + align:start position:0% +the dictator game 50 50 allocation in +the dictator game + + align:start position:0% +the dictator game + + + align:start position:0% +the dictator game +might be narrowly framed in that + + align:start position:0% +might be narrowly framed in that + + + align:start position:0% +might be narrowly framed in that +particular game fair but of course it's + + align:start position:0% +particular game fair but of course it's + + + align:start position:0% +particular game fair but of course it's +not fair in the grand scheme of things + + align:start position:0% +not fair in the grand scheme of things + + + align:start position:0% +not fair in the grand scheme of things +but what seems to be the case is that um + + align:start position:0% +but what seems to be the case is that um + + + align:start position:0% +but what seems to be the case is that um +and there's some evidence other evidence + + align:start position:0% +and there's some evidence other evidence + + + align:start position:0% +and there's some evidence other evidence +in the paper that you can read if you + + align:start position:0% +in the paper that you can read if you + + + align:start position:0% +in the paper that you can read if you +would like + + align:start position:0% +would like + + + align:start position:0% +would like +it seems to be the case that um rich + + align:start position:0% +it seems to be the case that um rich + + + align:start position:0% +it seems to be the case that um rich +children become more averse to unequal + + align:start position:0% +children become more averse to unequal + + + align:start position:0% +children become more averse to unequal +outcomes in the world in general because + + align:start position:0% +outcomes in the world in general because + + + align:start position:0% +outcomes in the world in general because +they essentially see + + align:start position:0% +they essentially see + + + align:start position:0% +they essentially see +these poor kids who who are very smart + + align:start position:0% +these poor kids who who are very smart + + + align:start position:0% +these poor kids who who are very smart +and you know um + + align:start position:0% +and you know um + + + align:start position:0% +and you know um +are disadvantaged in terms of various + + align:start position:0% +are disadvantaged in terms of various + + + align:start position:0% +are disadvantaged in terms of various +ways from like having + + align:start position:0% +ways from like having + + + align:start position:0% +ways from like having +a lower wealth of their parents the rich + + align:start position:0% +a lower wealth of their parents the rich + + + align:start position:0% +a lower wealth of their parents the rich +kids become sort of more averse against + + align:start position:0% +kids become sort of more averse against + + + align:start position:0% +kids become sort of more averse against +that + + align:start position:0% +that + + + align:start position:0% +that +and that translates even into like + + align:start position:0% +and that translates even into like + + + align:start position:0% +and that translates even into like +dictator games with + + align:start position:0% +dictator games with + + + align:start position:0% +dictator games with +other rich kids um in a very sort of + + align:start position:0% +other rich kids um in a very sort of + + + align:start position:0% +other rich kids um in a very sort of +minor thing in the world in in these + + align:start position:0% +minor thing in the world in in these + + + align:start position:0% +minor thing in the world in in these +dictator games + + align:start position:0% +dictator games + + + align:start position:0% +dictator games +again even though the dictator games + + align:start position:0% +again even though the dictator games + + + align:start position:0% +again even though the dictator games +actually don't change very much but they + + align:start position:0% +actually don't change very much but they + + + align:start position:0% +actually don't change very much but they +really seem to be + + align:start position:0% +really seem to be + + + align:start position:0% +really seem to be +averse to an equality of these outcomes + + align:start position:0% +averse to an equality of these outcomes + + + align:start position:0% +averse to an equality of these outcomes +and move them from the 10-0 allocation + + align:start position:0% +and move them from the 10-0 allocation + + + align:start position:0% +and move them from the 10-0 allocation +to + + align:start position:0% +to + + + align:start position:0% +to +50-50 even with these rich kids + + align:start position:0% + + + + align:start position:0% + +okay so that was like evidence on social + + align:start position:0% +okay so that was like evidence on social + + + align:start position:0% +okay so that was like evidence on social +preferences as measured by dictator + + align:start position:0% +preferences as measured by dictator + + + align:start position:0% +preferences as measured by dictator +games + + align:start position:0% +games + + + align:start position:0% +games +the paper also has some evidence on + + align:start position:0% +the paper also has some evidence on + + + align:start position:0% +the paper also has some evidence on +discrimination in particular a small + + align:start position:0% +discrimination in particular a small + + + align:start position:0% +discrimination in particular a small +field experiment on team selection + + align:start position:0% +field experiment on team selection + + + align:start position:0% +field experiment on team selection +so um what does the study do so the + + align:start position:0% +so um what does the study do so the + + + align:start position:0% +so um what does the study do so the +subjects + + align:start position:0% +subjects + + + align:start position:0% +subjects +are again students from two elite + + align:start position:0% +are again students from two elite + + + align:start position:0% +are again students from two elite +private schools so now it's like two of + + align:start position:0% +private schools so now it's like two of + + + align:start position:0% +private schools so now it's like two of +these + + align:start position:0% +these + + + align:start position:0% +these +selected student schools are selected + + align:start position:0% +selected student schools are selected + + + align:start position:0% +selected student schools are selected +one is a treatment school + + align:start position:0% +one is a treatment school + + + align:start position:0% +one is a treatment school +one is a control group and in addition + + align:start position:0% +one is a control group and in addition + + + align:start position:0% +one is a control group and in addition +gautam invited athletic poor students + + align:start position:0% +gautam invited athletic poor students + + + align:start position:0% +gautam invited athletic poor students +from a public school + + align:start position:0% +from a public school + + + align:start position:0% +from a public school +importantly these are athletic students + + align:start position:0% +importantly these are athletic students + + + align:start position:0% +importantly these are athletic students +these are students who are better at + + align:start position:0% +these are students who are better at + + + align:start position:0% +these are students who are better at +sports than + + align:start position:0% +sports than + + + align:start position:0% +sports than +the rich kids you might think you know + + align:start position:0% +the rich kids you might think you know + + + align:start position:0% +the rich kids you might think you know +the poorer kids are better at sports + + align:start position:0% +the poorer kids are better at sports + + + align:start position:0% +the poorer kids are better at sports +than the rich kids anyway which is + + align:start position:0% +than the rich kids anyway which is + + + align:start position:0% +than the rich kids anyway which is +probably true + + align:start position:0% +probably true + + + align:start position:0% +probably true +but now these are particularly athletic + + align:start position:0% +but now these are particularly athletic + + + align:start position:0% +but now these are particularly athletic +students on purpose + + align:start position:0% +students on purpose + + + align:start position:0% +students on purpose +who are invited to attend a sports event + + align:start position:0% +who are invited to attend a sports event + + + align:start position:0% +who are invited to attend a sports event +as well + + align:start position:0% +as well + + + align:start position:0% +as well +now students in this in this experiment + + align:start position:0% +now students in this in this experiment + + + align:start position:0% +now students in this in this experiment +in this game must + + align:start position:0% +in this game must + + + align:start position:0% +in this game must +choose teammates to run a relay race now + + align:start position:0% +choose teammates to run a relay race now + + + align:start position:0% +choose teammates to run a relay race now +when you know a rich kid who who is + + align:start position:0% +when you know a rich kid who who is + + + align:start position:0% +when you know a rich kid who who is +thinking about who + + align:start position:0% +thinking about who + + + align:start position:0% +thinking about who +who who should be in my team you can + + align:start position:0% +who who should be in my team you can + + + align:start position:0% +who who should be in my team you can +either choose like a rich kid + + align:start position:0% +either choose like a rich kid + + + align:start position:0% +either choose like a rich kid +who is kind of like similar to you and + + align:start position:0% +who is kind of like similar to you and + + + align:start position:0% +who is kind of like similar to you and +uh + + align:start position:0% +uh + + + align:start position:0% +uh +in social ways or or you can choose a + + align:start position:0% +in social ways or or you can choose a + + + align:start position:0% +in social ways or or you can choose a +poor kid + + align:start position:0% +poor kid + + + align:start position:0% +poor kid +who whom you don't know very much you + + align:start position:0% +who whom you don't know very much you + + + align:start position:0% +who whom you don't know very much you +might actually not like the poor kids + + align:start position:0% +might actually not like the poor kids + + + align:start position:0% +might actually not like the poor kids +but you know the poor kid is a lot + + align:start position:0% +but you know the poor kid is a lot + + + align:start position:0% +but you know the poor kid is a lot +better in the in the running + + align:start position:0% +better in the in the running + + + align:start position:0% +better in the in the running +um so it might be like much better for + + align:start position:0% +um so it might be like much better for + + + align:start position:0% +um so it might be like much better for +you might be much more likely to win in + + align:start position:0% +you might be much more likely to win in + + + align:start position:0% +you might be much more likely to win in +the game + + align:start position:0% +the game + + + align:start position:0% +the game +because now your partner in the relay + + align:start position:0% +because now your partner in the relay + + + align:start position:0% +because now your partner in the relay +race is much faster so it's a very nice + + align:start position:0% +race is much faster so it's a very nice + + + align:start position:0% +race is much faster so it's a very nice +trade-off between ability + + align:start position:0% +trade-off between ability + + + align:start position:0% +trade-off between ability +choosing uh the fast runner versus + + align:start position:0% +choosing uh the fast runner versus + + + align:start position:0% +choosing uh the fast runner versus +social similarity + + align:start position:0% +social similarity + + + align:start position:0% +social similarity +and now what what um uh gotten then is + + align:start position:0% +and now what what um uh gotten then is + + + align:start position:0% +and now what what um uh gotten then is +doing is like he uh if you sort of + + align:start position:0% +doing is like he uh if you sort of + + + align:start position:0% +doing is like he uh if you sort of +choose the rich kid + + align:start position:0% +choose the rich kid + + + align:start position:0% +choose the rich kid +that's then a measure of discrimination + + align:start position:0% +that's then a measure of discrimination + + + align:start position:0% +that's then a measure of discrimination +because essentially + + align:start position:0% +because essentially + + + align:start position:0% +because essentially +you're choosing a worse runner um + + align:start position:0% +you're choosing a worse runner um + + + align:start position:0% +you're choosing a worse runner um +in favor of like um or because you want + + align:start position:0% +in favor of like um or because you want + + + align:start position:0% +in favor of like um or because you want +more social similarity + + align:start position:0% +more social similarity + + + align:start position:0% +more social similarity +you don't want to hang out with a poor + + align:start position:0% +you don't want to hang out with a poor + + + align:start position:0% +you don't want to hang out with a poor +kid instead you choose the rich kid + + align:start position:0% +kid instead you choose the rich kid + + + align:start position:0% +kid instead you choose the rich kid +which reduces your chances in the race + + align:start position:0% +which reduces your chances in the race + + + align:start position:0% +which reduces your chances in the race +but increases your time + + align:start position:0% +but increases your time + + + align:start position:0% +but increases your time +spent with the rich kids compared to + + align:start position:0% +spent with the rich kids compared to + + + align:start position:0% +spent with the rich kids compared to +like poor kids + + align:start position:0% +like poor kids + + + align:start position:0% +like poor kids +let me tell you a little bit more detail + + align:start position:0% +let me tell you a little bit more detail + + + align:start position:0% +let me tell you a little bit more detail +of the experiment + + align:start position:0% +of the experiment + + + align:start position:0% +of the experiment +uh stage one is randomization so it was + + align:start position:0% +uh stage one is randomization so it was + + + align:start position:0% +uh stage one is randomization so it was +the + + align:start position:0% +the + + + align:start position:0% +the +the people were randomized to sessions + + align:start position:0% +the people were randomized to sessions + + + align:start position:0% +the people were randomized to sessions +with varying stakes + + align:start position:0% +with varying stakes + + + align:start position:0% +with varying stakes +there's uh 50 50 rupees 20 200 rupees + + align:start position:0% +there's uh 50 50 rupees 20 200 rupees + + + align:start position:0% +there's uh 50 50 rupees 20 200 rupees +500 rupees per + + align:start position:0% +500 rupees per + + + align:start position:0% +500 rupees per +uh student for the winning team this is + + align:start position:0% +uh student for the winning team this is + + + align:start position:0% +uh student for the winning team this is +a lot of money compared to like students + + align:start position:0% +a lot of money compared to like students + + + align:start position:0% +a lot of money compared to like students +usual pocket money right so they would + + align:start position:0% +usual pocket money right so they would + + + align:start position:0% +usual pocket money right so they would +get something like 10 + + align:start position:0% +get something like 10 + + + align:start position:0% +get something like 10 +or 500 rupees um is like one months of + + align:start position:0% +or 500 rupees um is like one months of + + + align:start position:0% +or 500 rupees um is like one months of +uh pocket money that's like really high + + align:start position:0% +uh pocket money that's like really high + + + align:start position:0% +uh pocket money that's like really high +stakes for these kids + + align:start position:0% +stakes for these kids + + + align:start position:0% +stakes for these kids +um the price is varied essentially + + align:start position:0% +um the price is varied essentially + + + align:start position:0% +um the price is varied essentially +because it lets us like price out it + + align:start position:0% +because it lets us like price out it + + + align:start position:0% +because it lets us like price out it +gives us a price of discrimination + + align:start position:0% +gives us a price of discrimination + + + align:start position:0% +gives us a price of discrimination +lets us understand how much are students + + align:start position:0% +lets us understand how much are students + + + align:start position:0% +lets us understand how much are students +willing to give up in order + + align:start position:0% +willing to give up in order + + + align:start position:0% +willing to give up in order +um uh to not have to um or + + align:start position:0% +um uh to not have to um or + + + align:start position:0% +um uh to not have to um or +in order to uh be able to socialize with + + align:start position:0% +in order to uh be able to socialize with + + + align:start position:0% +in order to uh be able to socialize with +the rich kids compared to a poor kid + + align:start position:0% +the rich kids compared to a poor kid + + + align:start position:0% +the rich kids compared to a poor kid +there was brief mixing to start with to + + align:start position:0% +there was brief mixing to start with to + + + align:start position:0% +there was brief mixing to start with to +judge socio-economic status + + align:start position:0% +judge socio-economic status + + + align:start position:0% +judge socio-economic status +right so the kids were like allowed to + + align:start position:0% +right so the kids were like allowed to + + + align:start position:0% +right so the kids were like allowed to +mingle a little bit that would allow + + align:start position:0% +mingle a little bit that would allow + + + align:start position:0% +mingle a little bit that would allow +them to + + align:start position:0% +them to + + + align:start position:0% +them to +fairly easily understand who's a poor + + align:start position:0% +fairly easily understand who's a poor + + + align:start position:0% +fairly easily understand who's a poor +kid and who's a + + align:start position:0% +kid and who's a + + + align:start position:0% +kid and who's a +rich kid okay stage number two was + + align:start position:0% +rich kid okay stage number two was + + + align:start position:0% +rich kid okay stage number two was +ability revelation and team selection so + + align:start position:0% +ability revelation and team selection so + + + align:start position:0% +ability revelation and team selection so +you could essentially observe a + + align:start position:0% +you could essentially observe a + + + align:start position:0% +you could essentially observe a +two-person race + + align:start position:0% +two-person race + + + align:start position:0% +two-person race +usually it's one poor and one rich + + align:start position:0% +usually it's one poor and one rich + + + align:start position:0% +usually it's one poor and one rich +students neither is from their own + + align:start position:0% +students neither is from their own + + + align:start position:0% +students neither is from their own +schools so these are not + + align:start position:0% +schools so these are not + + + align:start position:0% +schools so these are not +students that you would know from school + + align:start position:0% +students that you would know from school + + + align:start position:0% +students that you would know from school +anyway + + align:start position:0% +anyway + + + align:start position:0% +anyway +but the uniforms make the school + + align:start position:0% +but the uniforms make the school + + + align:start position:0% +but the uniforms make the school +identifiable do you kind of know who's + + align:start position:0% +identifiable do you kind of know who's + + + align:start position:0% +identifiable do you kind of know who's +the rich kid and who's the poor kid + + align:start position:0% +the rich kid and who's the poor kid + + + align:start position:0% +the rich kid and who's the poor kid +now then you can pick which of these two + + align:start position:0% +now then you can pick which of these two + + + align:start position:0% +now then you can pick which of these two +runners you want to have as your + + align:start position:0% +runners you want to have as your + + + align:start position:0% +runners you want to have as your +partners + + align:start position:0% +partners + + + align:start position:0% +partners +so that is to say you see them run + + align:start position:0% +so that is to say you see them run + + + align:start position:0% +so that is to say you see them run +one by one it's very easy to see like + + align:start position:0% +one by one it's very easy to see like + + + align:start position:0% +one by one it's very easy to see like +who's faster and who's not + + align:start position:0% +who's faster and who's not + + + align:start position:0% +who's faster and who's not +and so again discrimination here is um + + align:start position:0% +and so again discrimination here is um + + + align:start position:0% +and so again discrimination here is um +uh + + align:start position:0% +uh + + + align:start position:0% +uh +interpreted as like picking the slow + + align:start position:0% +interpreted as like picking the slow + + + align:start position:0% +interpreted as like picking the slow +runner so if you pick the slower runner + + align:start position:0% +runner so if you pick the slower runner + + + align:start position:0% +runner so if you pick the slower runner +and then it must be because you like + + align:start position:0% +and then it must be because you like + + + align:start position:0% +and then it must be because you like +something + + align:start position:0% +something + + + align:start position:0% +something +some other characteristics about that + + align:start position:0% +some other characteristics about that + + + align:start position:0% +some other characteristics about that +person more the obvious characteristic + + align:start position:0% +person more the obvious characteristic + + + align:start position:0% +person more the obvious characteristic +here is that + + align:start position:0% +here is that + + + align:start position:0% +here is that +it's most likely going to be that kid is + + align:start position:0% +it's most likely going to be that kid is + + + align:start position:0% +it's most likely going to be that kid is +rich + + align:start position:0% +rich + + + align:start position:0% +rich +okay then um uh + + align:start position:0% +okay then um uh + + + align:start position:0% +okay then um uh +stages three and four are on the choice + + align:start position:0% +stages three and four are on the choice + + + align:start position:0% +stages three and four are on the choice +implementation + + align:start position:0% +implementation + + + align:start position:0% +implementation +relay race so students are randomly + + align:start position:0% +relay race so students are randomly + + + align:start position:0% +relay race so students are randomly +picked to have their choices implemented + + align:start position:0% +picked to have their choices implemented + + + align:start position:0% +picked to have their choices implemented +so some of those choices + + align:start position:0% +so some of those choices + + + align:start position:0% +so some of those choices +this is again the strategy method some + + align:start position:0% +this is again the strategy method some + + + align:start position:0% +this is again the strategy method some +of these choices were actually randomly + + align:start position:0% +of these choices were actually randomly + + + align:start position:0% +of these choices were actually randomly +implemented + + align:start position:0% +implemented + + + align:start position:0% +implemented +so there's plausible deniability for um + + align:start position:0% +so there's plausible deniability for um + + + align:start position:0% +so there's plausible deniability for um +the students in the sense of like you + + align:start position:0% +the students in the sense of like you + + + align:start position:0% +the students in the sense of like you +could just uh + + align:start position:0% +could just uh + + + align:start position:0% +could just uh +you know you could just happen to be um + + align:start position:0% +you know you could just happen to be um + + + align:start position:0% +you know you could just happen to be um +randomized or + + align:start position:0% +randomized or + + + align:start position:0% +randomized or +you you happen to pick some students + + align:start position:0% +you you happen to pick some students + + + align:start position:0% +you you happen to pick some students +versus another uh + + align:start position:0% +versus another uh + + + align:start position:0% +versus another uh +could just be by chance that you are + + align:start position:0% +could just be by chance that you are + + + align:start position:0% +could just be by chance that you are +with one student versus another + + align:start position:0% +with one student versus another + + + align:start position:0% +with one student versus another +so you couldn't you're free to choose + + align:start position:0% +so you couldn't you're free to choose + + + align:start position:0% +so you couldn't you're free to choose +essentially provides you cover sometimes + + align:start position:0% +essentially provides you cover sometimes + + + align:start position:0% +essentially provides you cover sometimes +as we discussed before + + align:start position:0% +as we discussed before + + + align:start position:0% +as we discussed before +the computer is choosing so you always + + align:start position:0% +the computer is choosing so you always + + + align:start position:0% +the computer is choosing so you always +have an excuse so it's intended + + align:start position:0% +have an excuse so it's intended + + + align:start position:0% +have an excuse so it's intended +to reveal students true preferences as + + align:start position:0% +to reveal students true preferences as + + + align:start position:0% +to reveal students true preferences as +opposed to + + align:start position:0% +opposed to + + + align:start position:0% +opposed to +perhaps what they think that their + + align:start position:0% +perhaps what they think that their + + + align:start position:0% +perhaps what they think that their +friends want them to choose or uh + + align:start position:0% +friends want them to choose or uh + + + align:start position:0% +friends want them to choose or uh +the other runners then the relay races + + align:start position:0% +the other runners then the relay races + + + align:start position:0% +the other runners then the relay races +were actually held and prices were + + align:start position:0% +were actually held and prices were + + + align:start position:0% +were actually held and prices were +distributed as promised + + align:start position:0% +distributed as promised + + + align:start position:0% +distributed as promised +number four crucially there was a social + + align:start position:0% +number four crucially there was a social + + + align:start position:0% +number four crucially there was a social +interaction + + align:start position:0% +interaction + + + align:start position:0% +interaction +so if you picked like your teammate you + + align:start position:0% +so if you picked like your teammate you + + + align:start position:0% +so if you picked like your teammate you +actually have to spend two hours of + + align:start position:0% +actually have to spend two hours of + + + align:start position:0% +actually have to spend two hours of +playing with a teammate + + align:start position:0% +playing with a teammate + + + align:start position:0% +playing with a teammate +board games sports playgrounds and so on + + align:start position:0% +board games sports playgrounds and so on + + + align:start position:0% +board games sports playgrounds and so on +importantly this was pre-announced + + align:start position:0% +importantly this was pre-announced + + + align:start position:0% +importantly this was pre-announced +so now again as i said before when + + align:start position:0% +so now again as i said before when + + + align:start position:0% +so now again as i said before when +picking your partner + + align:start position:0% +picking your partner + + + align:start position:0% +picking your partner +you have the choice between either + + align:start position:0% +you have the choice between either + + + align:start position:0% +you have the choice between either +picking the fast + + align:start position:0% +picking the fast + + + align:start position:0% +picking the fast +poor kid which will really increase your + + align:start position:0% +poor kid which will really increase your + + + align:start position:0% +poor kid which will really increase your +probability of winning + + align:start position:0% +probability of winning + + + align:start position:0% +probability of winning +um or the rich kid who's kind of slow + + align:start position:0% +um or the rich kid who's kind of slow + + + align:start position:0% +um or the rich kid who's kind of slow +and will reduce your uh reduce your + + align:start position:0% +and will reduce your uh reduce your + + + align:start position:0% +and will reduce your uh reduce your +probability of winning + + align:start position:0% +probability of winning + + + align:start position:0% +probability of winning +but if you pick that poor kid or the + + align:start position:0% +but if you pick that poor kid or the + + + align:start position:0% +but if you pick that poor kid or the +rich kid you have to actually spend + + align:start position:0% +rich kid you have to actually spend + + + align:start position:0% +rich kid you have to actually spend +two hours with that teammate playing + + align:start position:0% +two hours with that teammate playing + + + align:start position:0% +two hours with that teammate playing +board game sports playground and so on + + align:start position:0% +board game sports playground and so on + + + align:start position:0% +board game sports playground and so on +and you might not want to do that with a + + align:start position:0% +and you might not want to do that with a + + + align:start position:0% +and you might not want to do that with a +poor kit + + align:start position:0% + + + + align:start position:0% + +okay so now first you know what is + + align:start position:0% +okay so now first you know what is + + + align:start position:0% +okay so now first you know what is +demand for um + + align:start position:0% +demand for um + + + align:start position:0% +demand for um +discrimination you can look at this + + align:start position:0% +discrimination you can look at this + + + align:start position:0% +discrimination you can look at this +graph it shows very nicely + + align:start position:0% +graph it shows very nicely + + + align:start position:0% +graph it shows very nicely +for the different prices as i said 500 + + align:start position:0% +for the different prices as i said 500 + + + align:start position:0% +for the different prices as i said 500 +rupees for winning the rice + + align:start position:0% +rupees for winning the rice + + + align:start position:0% +rupees for winning the rice +200 rupees or 500 rupees if you look at + + align:start position:0% +200 rupees or 500 rupees if you look at + + + align:start position:0% +200 rupees or 500 rupees if you look at +500 rupees this is again one month of + + align:start position:0% +500 rupees this is again one month of + + + align:start position:0% +500 rupees this is again one month of +pocket money + + align:start position:0% +pocket money + + + align:start position:0% +pocket money +there's no difference between treated + + align:start position:0% +there's no difference between treated + + + align:start position:0% +there's no difference between treated +and untreated classrooms + + align:start position:0% +and untreated classrooms + + + align:start position:0% +and untreated classrooms +that is to say so there's ten percent of + + align:start position:0% +that is to say so there's ten percent of + + + align:start position:0% +that is to say so there's ten percent of +people + + align:start position:0% +people + + + align:start position:0% +people +are um as you want discriminating the + + align:start position:0% +are um as you want discriminating the + + + align:start position:0% +are um as you want discriminating the +poor so ten percent or sorry + + align:start position:0% +poor so ten percent or sorry + + + align:start position:0% +poor so ten percent or sorry +this is less than ten percent is about + + align:start position:0% +this is less than ten percent is about + + + align:start position:0% +this is less than ten percent is about +um seven eight percent of students + + align:start position:0% +um seven eight percent of students + + + align:start position:0% +um seven eight percent of students +um pick the rich kids um even in the + + align:start position:0% +um pick the rich kids um even in the + + + align:start position:0% +um pick the rich kids um even in the +really really high stakes + + align:start position:0% +really really high stakes + + + align:start position:0% +really really high stakes +race that is to say when the stakes are + + align:start position:0% +race that is to say when the stakes are + + + align:start position:0% +race that is to say when the stakes are +500 rupees + + align:start position:0% +500 rupees + + + align:start position:0% +500 rupees +they're like about six seven eight + + align:start position:0% +they're like about six seven eight + + + align:start position:0% +they're like about six seven eight +percent of students + + align:start position:0% +percent of students + + + align:start position:0% +percent of students +who still pick the rich kid um and they + + align:start position:0% +who still pick the rich kid um and they + + + align:start position:0% +who still pick the rich kid um and they +sort of take into account + + align:start position:0% +sort of take into account + + + align:start position:0% +sort of take into account +the the um uh the chance that they that + + align:start position:0% +the the um uh the chance that they that + + + align:start position:0% +the the um uh the chance that they that +that might lose them the raise + + align:start position:0% +that might lose them the raise + + + align:start position:0% +that might lose them the raise +but um you know they don't have to spend + + align:start position:0% +but um you know they don't have to spend + + + align:start position:0% +but um you know they don't have to spend +two hours um + + align:start position:0% +two hours um + + + align:start position:0% +two hours um +uh with a poor kid than socializing now + + align:start position:0% +uh with a poor kid than socializing now + + + align:start position:0% +uh with a poor kid than socializing now +when you look at the lower prices + + align:start position:0% +when you look at the lower prices + + + align:start position:0% +when you look at the lower prices +the fraction as you expect this is the + + align:start position:0% +the fraction as you expect this is the + + + align:start position:0% +the fraction as you expect this is the +red line um + + align:start position:0% +red line um + + + align:start position:0% +red line um +sorry this is the green line the upper + + align:start position:0% +sorry this is the green line the upper + + + align:start position:0% +sorry this is the green line the upper +line the fraction would choose + + align:start position:0% +line the fraction would choose + + + align:start position:0% +line the fraction would choose +the rich kids the fraction who are + + align:start position:0% +the rich kids the fraction who are + + + align:start position:0% +the rich kids the fraction who are +discriminating against the poor + + align:start position:0% +discriminating against the poor + + + align:start position:0% +discriminating against the poor +increases + + align:start position:0% +increases + + + align:start position:0% +increases +as you expect so now it becomes cheaper + + align:start position:0% +as you expect so now it becomes cheaper + + + align:start position:0% +as you expect so now it becomes cheaper +it's only like the race is only 200 + + align:start position:0% +it's only like the race is only 200 + + + align:start position:0% +it's only like the race is only 200 +rupees or 50 rupees + + align:start position:0% +rupees or 50 rupees + + + align:start position:0% +rupees or 50 rupees +you might be more inclined to pick the + + align:start position:0% +you might be more inclined to pick the + + + align:start position:0% +you might be more inclined to pick the +rich kid because you know the value of + + align:start position:0% +rich kid because you know the value of + + + align:start position:0% +rich kid because you know the value of +socializing stays the same + + align:start position:0% +socializing stays the same + + + align:start position:0% +socializing stays the same +but the cost of picking the regicate the + + align:start position:0% +but the cost of picking the regicate the + + + align:start position:0% +but the cost of picking the regicate the +cost of losing the race + + align:start position:0% +cost of losing the race + + + align:start position:0% +cost of losing the race +potentially at least is reduced right + + align:start position:0% +potentially at least is reduced right + + + align:start position:0% +potentially at least is reduced right +the and sort of if you look at 50 rupees + + align:start position:0% +the and sort of if you look at 50 rupees + + + align:start position:0% +the and sort of if you look at 50 rupees +the price 50 rupees um for the game + + align:start position:0% +the price 50 rupees um for the game + + + align:start position:0% +the price 50 rupees um for the game +for the relay race uh uh that's um + + align:start position:0% +for the relay race uh uh that's um + + + align:start position:0% +for the relay race uh uh that's um +about almost like 40 percent of students + + align:start position:0% +about almost like 40 percent of students + + + align:start position:0% +about almost like 40 percent of students +now pick the rich kid + + align:start position:0% +now pick the rich kid + + + align:start position:0% +now pick the rich kid +even though that might lose them the + + align:start position:0% +even though that might lose them the + + + align:start position:0% +even though that might lose them the +race and now crucially + + align:start position:0% +race and now crucially + + + align:start position:0% +race and now crucially +in red this is the dashed line below you + + align:start position:0% +in red this is the dashed line below you + + + align:start position:0% +in red this is the dashed line below you +can see the treated classrooms + + align:start position:0% +can see the treated classrooms + + + align:start position:0% +can see the treated classrooms +and what he finds is that for 500 rupees + + align:start position:0% +and what he finds is that for 500 rupees + + + align:start position:0% +and what he finds is that for 500 rupees +when the stakes are really really high + + align:start position:0% +when the stakes are really really high + + + align:start position:0% +when the stakes are really really high +there's no effect essentially it doesn't + + align:start position:0% +there's no effect essentially it doesn't + + + align:start position:0% +there's no effect essentially it doesn't +really matter whether you're in a + + align:start position:0% +really matter whether you're in a + + + align:start position:0% +really matter whether you're in a +treated or + + align:start position:0% +treated or + + + align:start position:0% +treated or +non-treated classroom in part perhaps + + align:start position:0% +non-treated classroom in part perhaps + + + align:start position:0% +non-treated classroom in part perhaps +because there's not much room for + + align:start position:0% +because there's not much room for + + + align:start position:0% +because there's not much room for +going lower than that so essentially + + align:start position:0% +going lower than that so essentially + + + align:start position:0% +going lower than that so essentially +there's no effect on + + align:start position:0% +there's no effect on + + + align:start position:0% +there's no effect on +on there because you know the stakes are + + align:start position:0% +on there because you know the stakes are + + + align:start position:0% +on there because you know the stakes are +really really high anyway there's not + + align:start position:0% +really really high anyway there's not + + + align:start position:0% +really really high anyway there's not +much discrimination + + align:start position:0% +much discrimination + + + align:start position:0% +much discrimination +and having had a treated class having + + align:start position:0% +and having had a treated class having + + + align:start position:0% +and having had a treated class having +had a poor kid in your classroom doesn't + + align:start position:0% +had a poor kid in your classroom doesn't + + + align:start position:0% +had a poor kid in your classroom doesn't +really + + align:start position:0% +really + + + align:start position:0% +really +change that but then very clearly for + + align:start position:0% +change that but then very clearly for + + + align:start position:0% +change that but then very clearly for +200 rupees and 50 rupees the lower + + align:start position:0% +200 rupees and 50 rupees the lower + + + align:start position:0% +200 rupees and 50 rupees the lower +stakes there's a clear difference + + align:start position:0% +stakes there's a clear difference + + + align:start position:0% +stakes there's a clear difference +between the green and the red lines that + + align:start position:0% +between the green and the red lines that + + + align:start position:0% +between the green and the red lines that +is to say there's a lot less + + align:start position:0% +is to say there's a lot less + + + align:start position:0% +is to say there's a lot less +discrimination + + align:start position:0% +discrimination + + + align:start position:0% +discrimination +towards the poor kids poor kids a lot + + align:start position:0% +towards the poor kids poor kids a lot + + + align:start position:0% +towards the poor kids poor kids a lot +more likely to be chosen + + align:start position:0% +more likely to be chosen + + + align:start position:0% +more likely to be chosen +when a student had in treated classrooms + + align:start position:0% +when a student had in treated classrooms + + + align:start position:0% +when a student had in treated classrooms +when somebody had a poor kid another + + align:start position:0% +when somebody had a poor kid another + + + align:start position:0% +when somebody had a poor kid another +poor kid + + align:start position:0% +poor kid + + + align:start position:0% +poor kid +in their classroom for several years so + + align:start position:0% +in their classroom for several years so + + + align:start position:0% +in their classroom for several years so +that's to say + + align:start position:0% +that's to say + + + align:start position:0% +that's to say +there's being exposed to these poor + + align:start position:0% +there's being exposed to these poor + + + align:start position:0% +there's being exposed to these poor +children reduces discrimination + + align:start position:0% +children reduces discrimination + + + align:start position:0% +children reduces discrimination +among the poor among the rich students + + align:start position:0% +among the poor among the rich students + + + align:start position:0% +among the poor among the rich students +uh subsequently + + align:start position:0% +uh subsequently + + + align:start position:0% +uh subsequently +um this is the sort of the same graph + + align:start position:0% +um this is the sort of the same graph + + + align:start position:0% +um this is the sort of the same graph +that i showed you before + + align:start position:0% +that i showed you before + + + align:start position:0% +that i showed you before +again that's sort of consistent with + + align:start position:0% +again that's sort of consistent with + + + align:start position:0% +again that's sort of consistent with +what we have before it gets a little + + align:start position:0% +what we have before it gets a little + + + align:start position:0% +what we have before it gets a little +messier than we had seen previously + + align:start position:0% +messier than we had seen previously + + + align:start position:0% +messier than we had seen previously +but similarly even within classrooms uh + + align:start position:0% +but similarly even within classrooms uh + + + align:start position:0% +but similarly even within classrooms uh +if you look at like grades two and three + + align:start position:0% +if you look at like grades two and three + + + align:start position:0% +if you look at like grades two and three +versus four and five + + align:start position:0% +versus four and five + + + align:start position:0% +versus four and five +uh uh the effects seem to be uh + + align:start position:0% +uh uh the effects seem to be uh + + + align:start position:0% +uh uh the effects seem to be uh +concentrated more pronouns + + align:start position:0% +concentrated more pronouns + + + align:start position:0% +concentrated more pronouns +in grades uh two and three + + align:start position:0% +in grades uh two and three + + + align:start position:0% +in grades uh two and three +now finally as i said we + + align:start position:0% +now finally as i said we + + + align:start position:0% +now finally as i said we +we look at test scores and discipline so + + align:start position:0% +we look at test scores and discipline so + + + align:start position:0% +we look at test scores and discipline so +arguably there are some positive effects + + align:start position:0% +arguably there are some positive effects + + + align:start position:0% +arguably there are some positive effects +on social preferences and + + align:start position:0% +on social preferences and + + + align:start position:0% +on social preferences and +as i said before the policy question now + + align:start position:0% +as i said before the policy question now + + + align:start position:0% +as i said before the policy question now +is does that come + + align:start position:0% +is does that come + + + align:start position:0% +is does that come +at the cost of academic achievement in + + align:start position:0% +at the cost of academic achievement in + + + align:start position:0% +at the cost of academic achievement in +some ways so is it that your rich kid + + align:start position:0% +some ways so is it that your rich kid + + + align:start position:0% +some ways so is it that your rich kid +now by being exposed to the poor kids + + align:start position:0% +now by being exposed to the poor kids + + + align:start position:0% +now by being exposed to the poor kids +maybe + + align:start position:0% +maybe + + + align:start position:0% +maybe +somewhat nicer and more friendly and + + align:start position:0% +somewhat nicer and more friendly and + + + align:start position:0% +somewhat nicer and more friendly and +less discriminating against the poor + + align:start position:0% +less discriminating against the poor + + + align:start position:0% +less discriminating against the poor +um that's all and good but is it the + + align:start position:0% +um that's all and good but is it the + + + align:start position:0% +um that's all and good but is it the +case now that cloud that um + + align:start position:0% +case now that cloud that um + + + align:start position:0% +case now that cloud that um +test scores go down so gautam finds no + + align:start position:0% +test scores go down so gautam finds no + + + align:start position:0% +test scores go down so gautam finds no +effect on aggregate + + align:start position:0% +effect on aggregate + + + align:start position:0% +effect on aggregate +uh an aggregate test score index there's + + align:start position:0% +uh an aggregate test score index there's + + + align:start position:0% +uh an aggregate test score index there's +zero effects on hindi and math + + align:start position:0% +zero effects on hindi and math + + + align:start position:0% +zero effects on hindi and math +there's a little bit of like um + + align:start position:0% +there's a little bit of like um + + + align:start position:0% +there's a little bit of like um +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +a reduction in english scores of 0.09 + + align:start position:0% +a reduction in english scores of 0.09 + + + align:start position:0% +a reduction in english scores of 0.09 +standard deviations that's marginally + + align:start position:0% +standard deviations that's marginally + + + align:start position:0% +standard deviations that's marginally +significant + + align:start position:0% +significant + + + align:start position:0% +significant +you know that's suggestive but not + + align:start position:0% +you know that's suggestive but not + + + align:start position:0% +you know that's suggestive but not +perhaps + + align:start position:0% +perhaps + + + align:start position:0% +perhaps +particularly large + + align:start position:0% + + + + align:start position:0% + +so these effects are not not not + + align:start position:0% +so these effects are not not not + + + align:start position:0% +so these effects are not not not +particularly large in particular in + + align:start position:0% +particularly large in particular in + + + align:start position:0% +particularly large in particular in +aggregate so if you aggregate everything + + align:start position:0% +aggregate so if you aggregate everything + + + align:start position:0% +aggregate so if you aggregate everything +together + + align:start position:0% +together + + + align:start position:0% +together +there don't seem to be any uh + + align:start position:0% +there don't seem to be any uh + + + align:start position:0% +there don't seem to be any uh +significant effects + + align:start position:0% +significant effects + + + align:start position:0% +significant effects +so perhaps the english scores are + + align:start position:0% +so perhaps the english scores are + + + align:start position:0% +so perhaps the english scores are +suggestive + + align:start position:0% +suggestive + + + align:start position:0% +suggestive +but sort of not particularly large there + + align:start position:0% +but sort of not particularly large there + + + align:start position:0% +but sort of not particularly large there +are some mild effects on discipline + + align:start position:0% +are some mild effects on discipline + + + align:start position:0% +are some mild effects on discipline +interestingly there's an increase in + + align:start position:0% +interestingly there's an increase in + + + align:start position:0% +interestingly there's an increase in +swearing you think that's good or bad + + align:start position:0% +swearing you think that's good or bad + + + align:start position:0% +swearing you think that's good or bad +you can think about that um but sort of + + align:start position:0% +you can think about that um but sort of + + + align:start position:0% +you can think about that um but sort of +there seems to be a little bit of effect + + align:start position:0% +there seems to be a little bit of effect + + + align:start position:0% +there seems to be a little bit of effect +of of + + align:start position:0% +of of + + + align:start position:0% +of of +like in terms of like language uses use + + align:start position:0% +like in terms of like language uses use + + + align:start position:0% +like in terms of like language uses use +usage + + align:start position:0% +usage + + + align:start position:0% +usage +uh there's no effects on violent and + + align:start position:0% +uh there's no effects on violent and + + + align:start position:0% +uh there's no effects on violent and +disruptive behavior which you might + + align:start position:0% +disruptive behavior which you might + + + align:start position:0% +disruptive behavior which you might +think is like + + align:start position:0% +think is like + + + align:start position:0% +think is like +a lot more damaging potentially + + align:start position:0% +a lot more damaging potentially + + + align:start position:0% +a lot more damaging potentially +okay so just summarizing what does the + + align:start position:0% +okay so just summarizing what does the + + + align:start position:0% +okay so just summarizing what does the +paper find well having + + align:start position:0% +paper find well having + + + align:start position:0% +paper find well having +poor classmates makes wealthy students + + align:start position:0% +poor classmates makes wealthy students + + + align:start position:0% +poor classmates makes wealthy students +more pro-social and generous + + align:start position:0% +more pro-social and generous + + + align:start position:0% +more pro-social and generous +they're more likely to volunteer for + + align:start position:0% +they're more likely to volunteer for + + + align:start position:0% +they're more likely to volunteer for +charities + + align:start position:0% +charities + + + align:start position:0% +charities +i didn't show you that evidence but + + align:start position:0% +i didn't show you that evidence but + + + align:start position:0% +i didn't show you that evidence but +that's another piece of evidence that he + + align:start position:0% +that's another piece of evidence that he + + + align:start position:0% +that's another piece of evidence that he +finds + + align:start position:0% +finds + + + align:start position:0% +finds +they're more likely to give in money and + + align:start position:0% +they're more likely to give in money and + + + align:start position:0% +they're more likely to give in money and +dictator games to give more + + align:start position:0% +dictator games to give more + + + align:start position:0% +dictator games to give more +higher fractions of their shared in + + align:start position:0% +higher fractions of their shared in + + + align:start position:0% +higher fractions of their shared in +dictator games + + align:start position:0% +dictator games + + + align:start position:0% +dictator games +they also choose more equitable + + align:start position:0% +they also choose more equitable + + + align:start position:0% +they also choose more equitable +outcomes and sort of disinterested + + align:start position:0% +outcomes and sort of disinterested + + + align:start position:0% +outcomes and sort of disinterested +third-party games where essentially you + + align:start position:0% +third-party games where essentially you + + + align:start position:0% +third-party games where essentially you +choose between two other + + align:start position:0% +choose between two other + + + align:start position:0% +choose between two other +students and their allocation so it's + + align:start position:0% +students and their allocation so it's + + + align:start position:0% +students and their allocation so it's +not just that they're more + + align:start position:0% +not just that they're more + + + align:start position:0% +not just that they're more +likely to willing to give up money that + + align:start position:0% +likely to willing to give up money that + + + align:start position:0% +likely to willing to give up money that +others get but also they're more likely + + align:start position:0% +others get but also they're more likely + + + align:start position:0% +others get but also they're more likely +to choose equal allocations + + align:start position:0% +to choose equal allocations + + + align:start position:0% +to choose equal allocations +in third-party games and disinterested + + align:start position:0% +in third-party games and disinterested + + + align:start position:0% +in third-party games and disinterested +games again i didn't show you that + + align:start position:0% +games again i didn't show you that + + + align:start position:0% +games again i didn't show you that +evidence but it seems to be + + align:start position:0% +evidence but it seems to be + + + align:start position:0% +evidence but it seems to be +that what's increasing here is sort of + + align:start position:0% +that what's increasing here is sort of + + + align:start position:0% +that what's increasing here is sort of +like inequality aversion + + align:start position:0% +like inequality aversion + + + align:start position:0% +like inequality aversion +um and these sort of disinterested um uh + + align:start position:0% +um and these sort of disinterested um uh + + + align:start position:0% +um and these sort of disinterested um uh +uh uh dictator or other types of games + + align:start position:0% +uh uh dictator or other types of games + + + align:start position:0% +uh uh dictator or other types of games +where essentially um these students by + + align:start position:0% +where essentially um these students by + + + align:start position:0% +where essentially um these students by +being exposed to poor kids + + align:start position:0% +being exposed to poor kids + + + align:start position:0% +being exposed to poor kids +are now more averse against + + align:start position:0% +are now more averse against + + + align:start position:0% +are now more averse against +unequal outcomes in these types of games + + align:start position:0% +unequal outcomes in these types of games + + + align:start position:0% +unequal outcomes in these types of games +second there is like less discrimination + + align:start position:0% +second there is like less discrimination + + + align:start position:0% +second there is like less discrimination +and more higher willingness to socialize + + align:start position:0% +and more higher willingness to socialize + + + align:start position:0% +and more higher willingness to socialize +with the poor + + align:start position:0% +with the poor + + + align:start position:0% +with the poor +they're more likely to choose poor + + align:start position:0% +they're more likely to choose poor + + + align:start position:0% +they're more likely to choose poor +teammates + + align:start position:0% +teammates + + + align:start position:0% +teammates +in sports contests they're also more + + align:start position:0% +in sports contests they're also more + + + align:start position:0% +in sports contests they're also more +willing to attend play dates with poor + + align:start position:0% +willing to attend play dates with poor + + + align:start position:0% +willing to attend play dates with poor +children again i didn't + + align:start position:0% +children again i didn't + + + align:start position:0% +children again i didn't +show you that evidence and then there's + + align:start position:0% +show you that evidence and then there's + + + align:start position:0% +show you that evidence and then there's +like some small negative effects on + + align:start position:0% +like some small negative effects on + + + align:start position:0% +like some small negative effects on +academic + + align:start position:0% +academic + + + align:start position:0% +academic +outcomes that i think are mostly + + align:start position:0% +outcomes that i think are mostly + + + align:start position:0% +outcomes that i think are mostly +negligible + + align:start position:0% +negligible + + + align:start position:0% +negligible +now there's an other work on the contact + + align:start position:0% +now there's an other work on the contact + + + align:start position:0% +now there's an other work on the contact +hypothesis which i showed you so the + + align:start position:0% +hypothesis which i showed you so the + + + align:start position:0% +hypothesis which i showed you so the +contact what is the contact hypothesis + + align:start position:0% +contact what is the contact hypothesis + + + align:start position:0% +contact what is the contact hypothesis +the contact hypothesis is from uh goes + + align:start position:0% +the contact hypothesis is from uh goes + + + align:start position:0% +the contact hypothesis is from uh goes +back to at least + + align:start position:0% +back to at least + + + align:start position:0% +back to at least +alport in 1954 which is the idea that + + align:start position:0% +alport in 1954 which is the idea that + + + align:start position:0% +alport in 1954 which is the idea that +interpersonal contacts reduces prejudice + + align:start position:0% +interpersonal contacts reduces prejudice + + + align:start position:0% +interpersonal contacts reduces prejudice +until certain conditions and not just + + align:start position:0% +until certain conditions and not just + + + align:start position:0% +until certain conditions and not just +prejudice but also + + align:start position:0% +prejudice but also + + + align:start position:0% +prejudice but also +changes attitudes and social preferences + + align:start position:0% +changes attitudes and social preferences + + + align:start position:0% +changes attitudes and social preferences +potentially + + align:start position:0% +potentially + + + align:start position:0% +potentially +so matt lowe who is a phd student here + + align:start position:0% +so matt lowe who is a phd student here + + + align:start position:0% +so matt lowe who is a phd student here +at mit has a very nice paper that looks + + align:start position:0% +at mit has a very nice paper that looks + + + align:start position:0% +at mit has a very nice paper that looks +at + + align:start position:0% +at + + + align:start position:0% +at +cricket tournaments and asks the + + align:start position:0% +cricket tournaments and asks the + + + align:start position:0% +cricket tournaments and asks the +question whether cricket leagues in + + align:start position:0% +question whether cricket leagues in + + + align:start position:0% +question whether cricket leagues in +india + + align:start position:0% +india + + + align:start position:0% +india +can increase cross-cast interaction and + + align:start position:0% +can increase cross-cast interaction and + + + align:start position:0% +can increase cross-cast interaction and +pro-sociality so what he does is he + + align:start position:0% +pro-sociality so what he does is he + + + align:start position:0% +pro-sociality so what he does is he +randomizes + + align:start position:0% +randomizes + + + align:start position:0% +randomizes +uh essentially cricket leaks and teams + + align:start position:0% +uh essentially cricket leaks and teams + + + align:start position:0% +uh essentially cricket leaks and teams +and cricket leaks + + align:start position:0% +and cricket leaks + + + align:start position:0% +and cricket leaks +where people across different casts are + + align:start position:0% +where people across different casts are + + + align:start position:0% +where people across different casts are +now more or less likely to play with + + align:start position:0% +now more or less likely to play with + + + align:start position:0% +now more or less likely to play with +each other + + align:start position:0% +each other + + + align:start position:0% +each other +both in terms of like um he varies or + + align:start position:0% +both in terms of like um he varies or + + + align:start position:0% +both in terms of like um he varies or +there's variation in the study + + align:start position:0% +there's variation in the study + + + align:start position:0% +there's variation in the study +within teams so are you more or less + + align:start position:0% +within teams so are you more or less + + + align:start position:0% +within teams so are you more or less +likely to have + + align:start position:0% +likely to have + + + align:start position:0% +likely to have +a or people some people are more or less + + align:start position:0% +a or people some people are more or less + + + align:start position:0% +a or people some people are more or less +likely to have a + + align:start position:0% +likely to have a + + + align:start position:0% +likely to have a +lower higher caste a person from a + + align:start position:0% +lower higher caste a person from a + + + align:start position:0% +lower higher caste a person from a +different cast + + align:start position:0% +different cast + + + align:start position:0% +different cast +in their team and he has um variation in + + align:start position:0% +in their team and he has um variation in + + + align:start position:0% +in their team and he has um variation in +what he calls + + align:start position:0% +what he calls + + + align:start position:0% +what he calls +adversarial contact which is like + + align:start position:0% +adversarial contact which is like + + + align:start position:0% +adversarial contact which is like +they're more or less likely to be + + align:start position:0% +they're more or less likely to be + + + align:start position:0% +they're more or less likely to be +exposed to + + align:start position:0% +exposed to + + + align:start position:0% +exposed to +uh uh players from other teams uh + + align:start position:0% +uh uh players from other teams uh + + + align:start position:0% +uh uh players from other teams uh +uh in higher different casts from + + align:start position:0% +uh in higher different casts from + + + align:start position:0% +uh in higher different casts from +themselves right so if you're on the + + align:start position:0% +themselves right so if you're on the + + + align:start position:0% +themselves right so if you're on the +team + + align:start position:0% +team + + + align:start position:0% +team +and have like a person from a different + + align:start position:0% +and have like a person from a different + + + align:start position:0% +and have like a person from a different +cast on your team + + align:start position:0% +cast on your team + + + align:start position:0% +cast on your team +you're on the same team you share the + + align:start position:0% +you're on the same team you share the + + + align:start position:0% +you're on the same team you share the +same objective and you want to win + + align:start position:0% +same objective and you want to win + + + align:start position:0% +same objective and you want to win +together so now be having somebody from + + align:start position:0% +together so now be having somebody from + + + align:start position:0% +together so now be having somebody from +a different task or just somebody who's + + align:start position:0% +a different task or just somebody who's + + + align:start position:0% +a different task or just somebody who's +different in various ways in your team + + align:start position:0% +different in various ways in your team + + + align:start position:0% +different in various ways in your team +might like might uh make you like them + + align:start position:0% +might like might uh make you like them + + + align:start position:0% +might like might uh make you like them +better you might be sort of more + + align:start position:0% +better you might be sort of more + + + align:start position:0% +better you might be sort of more +positive about them + + align:start position:0% +positive about them + + + align:start position:0% +positive about them +um uh you might be sort of more likely + + align:start position:0% +um uh you might be sort of more likely + + + align:start position:0% +um uh you might be sort of more likely +to talk to them + + align:start position:0% +to talk to them + + + align:start position:0% +to talk to them +you might learn about them you might + + align:start position:0% +you might learn about them you might + + + align:start position:0% +you might learn about them you might +sort of see some sides in them that you + + align:start position:0% +sort of see some sides in them that you + + + align:start position:0% +sort of see some sides in them that you +hadn't seen before + + align:start position:0% +hadn't seen before + + + align:start position:0% +hadn't seen before +so you might be more likely to empathize + + align:start position:0% +so you might be more likely to empathize + + + align:start position:0% +so you might be more likely to empathize +and look at sort of nice characteristics + + align:start position:0% +and look at sort of nice characteristics + + + align:start position:0% +and look at sort of nice characteristics +of them + + align:start position:0% +of them + + + align:start position:0% +of them +and sort of update them positively about + + align:start position:0% +and sort of update them positively about + + + align:start position:0% +and sort of update them positively about +people from other tasks + + align:start position:0% +people from other tasks + + + align:start position:0% +people from other tasks +and that changes your attitudes towards + + align:start position:0% +and that changes your attitudes towards + + + align:start position:0% +and that changes your attitudes towards +them in general + + align:start position:0% +them in general + + + align:start position:0% +them in general +if however you play against somebody + + align:start position:0% +if however you play against somebody + + + align:start position:0% +if however you play against somebody +from different casts + + align:start position:0% +from different casts + + + align:start position:0% +from different casts +you might actually that might actually + + align:start position:0% +you might actually that might actually + + + align:start position:0% +you might actually that might actually +if anything backfire because you know + + align:start position:0% +if anything backfire because you know + + + align:start position:0% +if anything backfire because you know +you really + + align:start position:0% +you really + + + align:start position:0% +you really +don't like your opponents you might see + + align:start position:0% +don't like your opponents you might see + + + align:start position:0% +don't like your opponents you might see +them very negatively you might be + + align:start position:0% +them very negatively you might be + + + align:start position:0% +them very negatively you might be +aggressive towards them you might be + + align:start position:0% +aggressive towards them you might be + + + align:start position:0% +aggressive towards them you might be +unfriendly towards them + + align:start position:0% +unfriendly towards them + + + align:start position:0% +unfriendly towards them +you might sort of um not like it that + + align:start position:0% +you might sort of um not like it that + + + align:start position:0% +you might sort of um not like it that +they win against you or the like + + align:start position:0% +they win against you or the like + + + align:start position:0% +they win against you or the like +so um this ad these adversarial + + align:start position:0% +so um this ad these adversarial + + + align:start position:0% +so um this ad these adversarial +interactions might actually + + align:start position:0% +interactions might actually + + + align:start position:0% +interactions might actually +backfire in the sense that they might + + align:start position:0% +backfire in the sense that they might + + + align:start position:0% +backfire in the sense that they might +not foster integration but actually sort + + align:start position:0% +not foster integration but actually sort + + + align:start position:0% +not foster integration but actually sort +of + + align:start position:0% +of + + + align:start position:0% +of +uh make things um uh uh worse + + align:start position:0% +uh make things um uh uh worse + + + align:start position:0% +uh make things um uh uh worse +so um matt runs this experiment and + + align:start position:0% +so um matt runs this experiment and + + + align:start position:0% +so um matt runs this experiment and +finds + + align:start position:0% +finds + + + align:start position:0% +finds +evidence of increased cross-cast + + align:start position:0% +evidence of increased cross-cast + + + align:start position:0% +evidence of increased cross-cast +interactions so people are more likely + + align:start position:0% +interactions so people are more likely + + + align:start position:0% +interactions so people are more likely +to + + align:start position:0% +to + + + align:start position:0% +to +be friends more likely to hang out with + + align:start position:0% +be friends more likely to hang out with + + + align:start position:0% +be friends more likely to hang out with +others they also + + align:start position:0% +others they also + + + align:start position:0% +others they also +are more generous in dictator and other + + align:start position:0% +are more generous in dictator and other + + + align:start position:0% +are more generous in dictator and other +types of games + + align:start position:0% +types of games + + + align:start position:0% +types of games +they're also more likely to engage and + + align:start position:0% +they're also more likely to engage and + + + align:start position:0% +they're also more likely to engage and +trade um + + align:start position:0% +trade um + + + align:start position:0% +trade um +or in economic exchange so much what + + align:start position:0% +or in economic exchange so much what + + + align:start position:0% +or in economic exchange so much what +matt does is sort of he randomizes + + align:start position:0% +matt does is sort of he randomizes + + + align:start position:0% +matt does is sort of he randomizes +gloves there's like left + + align:start position:0% +gloves there's like left + + + align:start position:0% +gloves there's like left +left gloves and right gloves and he has + + align:start position:0% +left gloves and right gloves and he has + + + align:start position:0% +left gloves and right gloves and he has +the same for flip-flops left flip-flops + + align:start position:0% +the same for flip-flops left flip-flops + + + align:start position:0% +the same for flip-flops left flip-flops +and right flip-flops + + align:start position:0% +and right flip-flops + + + align:start position:0% +and right flip-flops +and people are more likely to trade with + + align:start position:0% +and people are more likely to trade with + + + align:start position:0% +and people are more likely to trade with +somebody from another cast + + align:start position:0% +somebody from another cast + + + align:start position:0% +somebody from another cast +if they have been uh on the same team + + align:start position:0% +if they have been uh on the same team + + + align:start position:0% +if they have been uh on the same team +with people from other class if they + + align:start position:0% +with people from other class if they + + + align:start position:0% +with people from other class if they +have a higher fraction of people on + + align:start position:0% +have a higher fraction of people on + + + align:start position:0% +have a higher fraction of people on +their + + align:start position:0% +their + + + align:start position:0% +their +uh uh on their team of people from other + + align:start position:0% +uh uh on their team of people from other + + + align:start position:0% +uh uh on their team of people from other +casts + + align:start position:0% +casts + + + align:start position:0% +casts +they're more likely to engage in all + + align:start position:0% +they're more likely to engage in all + + + align:start position:0% +they're more likely to engage in all +these behaviors they're more likely to + + align:start position:0% +these behaviors they're more likely to + + + align:start position:0% +these behaviors they're more likely to +have cross-cast interaction more likely + + align:start position:0% +have cross-cast interaction more likely + + + align:start position:0% +have cross-cast interaction more likely +to be pro-social + + align:start position:0% +to be pro-social + + + align:start position:0% +to be pro-social +more likely to engage in economic + + align:start position:0% +more likely to engage in economic + + + align:start position:0% +more likely to engage in economic +exchange with people from other + + align:start position:0% +exchange with people from other + + + align:start position:0% +exchange with people from other +casts so that's all true for + + align:start position:0% +casts so that's all true for + + + align:start position:0% +casts so that's all true for +um a collaborative contact that is to + + align:start position:0% +um a collaborative contact that is to + + + align:start position:0% +um a collaborative contact that is to +say that it's contact with people + + align:start position:0% +say that it's contact with people + + + align:start position:0% +say that it's contact with people +uh on the same team in contrast for + + align:start position:0% +uh on the same team in contrast for + + + align:start position:0% +uh on the same team in contrast for +adversarial interactions when people are + + align:start position:0% +adversarial interactions when people are + + + align:start position:0% +adversarial interactions when people are +in the opposite team + + align:start position:0% +in the opposite team + + + align:start position:0% +in the opposite team +having more people from other casts are + + align:start position:0% +having more people from other casts are + + + align:start position:0% +having more people from other casts are +being exposed to more people from other + + align:start position:0% +being exposed to more people from other + + + align:start position:0% +being exposed to more people from other +casts + + align:start position:0% +casts + + + align:start position:0% +casts +uh does not have these positive effects + + align:start position:0% +uh does not have these positive effects + + + align:start position:0% +uh does not have these positive effects +and for some of these outcomes have even + + align:start position:0% +and for some of these outcomes have even + + + align:start position:0% +and for some of these outcomes have even +negative effects + + align:start position:0% +negative effects + + + align:start position:0% +negative effects +so if anything it sort of backfires it + + align:start position:0% +so if anything it sort of backfires it + + + align:start position:0% +so if anything it sort of backfires it +doesn't just + + align:start position:0% +doesn't just + + + align:start position:0% +doesn't just +just a mere exposure to others if you + + align:start position:0% +just a mere exposure to others if you + + + align:start position:0% +just a mere exposure to others if you +were sort of in an adversarial contact + + align:start position:0% +were sort of in an adversarial contact + + + align:start position:0% +were sort of in an adversarial contact +situation + + align:start position:0% +situation + + + align:start position:0% +situation +does not really foster uh pro-sociality + + align:start position:0% +does not really foster uh pro-sociality + + + align:start position:0% +does not really foster uh pro-sociality +or any of these + + align:start position:0% +or any of these + + + align:start position:0% +or any of these +types of integration if anything it + + align:start position:0% +types of integration if anything it + + + align:start position:0% +types of integration if anything it +backfires + + align:start position:0% +backfires + + + align:start position:0% +backfires +now why is that important when you think + + align:start position:0% +now why is that important when you think + + + align:start position:0% +now why is that important when you think +about like for example attitudes towards + + align:start position:0% +about like for example attitudes towards + + + align:start position:0% +about like for example attitudes towards +immigrants + + align:start position:0% +immigrants + + + align:start position:0% +immigrants +um it really matters hugely what types + + align:start position:0% +um it really matters hugely what types + + + align:start position:0% +um it really matters hugely what types +of contacts people are exposed to + + align:start position:0% +of contacts people are exposed to + + + align:start position:0% +of contacts people are exposed to +if people work together in the same team + + align:start position:0% +if people work together in the same team + + + align:start position:0% +if people work together in the same team +if they have perhaps like team pay + + align:start position:0% +if they have perhaps like team pay + + + align:start position:0% +if they have perhaps like team pay +if they want to like work towards the + + align:start position:0% +if they want to like work towards the + + + align:start position:0% +if they want to like work towards the +same goal + + align:start position:0% +same goal + + + align:start position:0% +same goal +really that can it seems this evidence + + align:start position:0% +really that can it seems this evidence + + + align:start position:0% +really that can it seems this evidence +suggests can foster pro-sociology + + align:start position:0% +suggests can foster pro-sociology + + + align:start position:0% +suggests can foster pro-sociology +uh and so on and so forth that leads to + + align:start position:0% +uh and so on and so forth that leads to + + + align:start position:0% +uh and so on and so forth that leads to +integration + + align:start position:0% +integration + + + align:start position:0% +integration +reduced discrimination and so on and so + + align:start position:0% +reduced discrimination and so on and so + + + align:start position:0% +reduced discrimination and so on and so +forth so if sort of the incentives are + + align:start position:0% +forth so if sort of the incentives are + + + align:start position:0% +forth so if sort of the incentives are +aligned or if we could sort of set up + + align:start position:0% +aligned or if we could sort of set up + + + align:start position:0% +aligned or if we could sort of set up +incentives that are aligned + + align:start position:0% +incentives that are aligned + + + align:start position:0% +incentives that are aligned +people might become nicer to each other + + align:start position:0% +people might become nicer to each other + + + align:start position:0% +people might become nicer to each other +and + + align:start position:0% + + + + align:start position:0% + +interactions might be fostered in + + align:start position:0% +interactions might be fostered in + + + align:start position:0% +interactions might be fostered in +contrast if contact is adversarial + + align:start position:0% +contrast if contact is adversarial + + + align:start position:0% +contrast if contact is adversarial +if you're worried that immigrants are + + align:start position:0% +if you're worried that immigrants are + + + align:start position:0% +if you're worried that immigrants are +taking away your jobs or like + + align:start position:0% +taking away your jobs or like + + + align:start position:0% +taking away your jobs or like +being exposed to immigrants might just + + align:start position:0% +being exposed to immigrants might just + + + align:start position:0% +being exposed to immigrants might just +do the opposite right so you might see a + + align:start position:0% +do the opposite right so you might see a + + + align:start position:0% +do the opposite right so you might see a +lot of immigrants + + align:start position:0% +lot of immigrants + + + align:start position:0% +lot of immigrants +but in a way if you feel like you're in + + align:start position:0% +but in a way if you feel like you're in + + + align:start position:0% +but in a way if you feel like you're in +competition with them if they're + + align:start position:0% +competition with them if they're + + + align:start position:0% +competition with them if they're +adversarial if they're sort of you're + + align:start position:0% +adversarial if they're sort of you're + + + align:start position:0% +adversarial if they're sort of you're +your enemies in some ways or your + + align:start position:0% +your enemies in some ways or your + + + align:start position:0% +your enemies in some ways or your +opponents and like some competition for + + align:start position:0% +opponents and like some competition for + + + align:start position:0% +opponents and like some competition for +a job + + align:start position:0% +a job + + + align:start position:0% +a job +being exposed to them might things in + + align:start position:0% +being exposed to them might things in + + + align:start position:0% +being exposed to them might things in +fact if anything + + align:start position:0% +fact if anything + + + align:start position:0% +fact if anything +uh uh uh uh worse + + align:start position:0% +uh uh uh uh worse + + + align:start position:0% +uh uh uh uh worse +um finally there's a another piece of + + align:start position:0% +um finally there's a another piece of + + + align:start position:0% +um finally there's a another piece of +very nice uh + + align:start position:0% +very nice uh + + + align:start position:0% +very nice uh +evidence by corn oidal this is um papers + + align:start position:0% +evidence by corn oidal this is um papers + + + align:start position:0% +evidence by corn oidal this is um papers +considering the + + align:start position:0% +considering the + + + align:start position:0% +considering the +impact of random interracial + + align:start position:0% +impact of random interracial + + + align:start position:0% +impact of random interracial +interactions among college roommates + + align:start position:0% +interactions among college roommates + + + align:start position:0% +interactions among college roommates +um in south africa on stereotypes + + align:start position:0% +um in south africa on stereotypes + + + align:start position:0% +um in south africa on stereotypes +attitudes and performance so what they + + align:start position:0% +attitudes and performance so what they + + + align:start position:0% +attitudes and performance so what they +look at essentially + + align:start position:0% +look at essentially + + + align:start position:0% +look at essentially +is roommates of different race um + + align:start position:0% + + + + align:start position:0% + +reduces so these are black and white + + align:start position:0% +reduces so these are black and white + + + align:start position:0% +reduces so these are black and white +students reduces + + align:start position:0% +students reduces + + + align:start position:0% +students reduces +white students stereotypes towards + + align:start position:0% +white students stereotypes towards + + + align:start position:0% +white students stereotypes towards +blacks and increases interracial + + align:start position:0% +blacks and increases interracial + + + align:start position:0% +blacks and increases interracial +friendships it also improves grades and + + align:start position:0% +friendships it also improves grades and + + + align:start position:0% +friendships it also improves grades and +lowers dropouts among blacks so there's + + align:start position:0% +lowers dropouts among blacks so there's + + + align:start position:0% +lowers dropouts among blacks so there's +sort of a number of positive effects + + align:start position:0% +sort of a number of positive effects + + + align:start position:0% +sort of a number of positive effects +of a very simple policy of like + + align:start position:0% +of a very simple policy of like + + + align:start position:0% +of a very simple policy of like +increasing contacts among roommates and + + align:start position:0% +increasing contacts among roommates and + + + align:start position:0% +increasing contacts among roommates and +again if you think about this evidence + + align:start position:0% +again if you think about this evidence + + + align:start position:0% +again if you think about this evidence +it seems to suggest that perhaps that's + + align:start position:0% +it seems to suggest that perhaps that's + + + align:start position:0% +it seems to suggest that perhaps that's +kind of like if you have a roommate + + align:start position:0% +kind of like if you have a roommate + + + align:start position:0% +kind of like if you have a roommate +that you're going to live with for quite + + align:start position:0% +that you're going to live with for quite + + + align:start position:0% +that you're going to live with for quite +a while that feels a lot like + + align:start position:0% +a while that feels a lot like + + + align:start position:0% +a while that feels a lot like +collaborative contact in the sense of + + align:start position:0% +collaborative contact in the sense of + + + align:start position:0% +collaborative contact in the sense of +like you're sort of stuck with that + + align:start position:0% +like you're sort of stuck with that + + + align:start position:0% +like you're sort of stuck with that +roommate for quite a while + + align:start position:0% +roommate for quite a while + + + align:start position:0% +roommate for quite a while +so you might as well sort of make the + + align:start position:0% +so you might as well sort of make the + + + align:start position:0% +so you might as well sort of make the +best out of it even if you initially + + align:start position:0% +best out of it even if you initially + + + align:start position:0% +best out of it even if you initially +don't like that person + + align:start position:0% +don't like that person + + + align:start position:0% +don't like that person +and you have the same objectives of + + align:start position:0% +and you have the same objectives of + + + align:start position:0% +and you have the same objectives of +being happy together living together + + align:start position:0% +being happy together living together + + + align:start position:0% +being happy together living together +and that really seems to foster and have + + align:start position:0% +and that really seems to foster and have + + + align:start position:0% +and that really seems to foster and have +some positive + + align:start position:0% +some positive + + + align:start position:0% +some positive +benefits + + align:start position:0% +benefits + + + align:start position:0% +benefits +so taking together that sort of says um + + align:start position:0% +so taking together that sort of says um + + + align:start position:0% +so taking together that sort of says um +so a you know the contact hypothesis + + align:start position:0% +so a you know the contact hypothesis + + + align:start position:0% +so a you know the contact hypothesis +seems to be broadly right + + align:start position:0% +seems to be broadly right + + + align:start position:0% +seems to be broadly right +uh contact to people who are different + + align:start position:0% +uh contact to people who are different + + + align:start position:0% +uh contact to people who are different +from you um + + align:start position:0% +from you um + + + align:start position:0% +from you um +uh might make you more tolerant or more + + align:start position:0% +uh might make you more tolerant or more + + + align:start position:0% +uh might make you more tolerant or more +pro-social + + align:start position:0% +pro-social + + + align:start position:0% +pro-social +towards them there might be more sort of + + align:start position:0% +towards them there might be more sort of + + + align:start position:0% +towards them there might be more sort of +integration of different groups + + align:start position:0% +integration of different groups + + + align:start position:0% +integration of different groups +but what really seems to matter quite a + + align:start position:0% +but what really seems to matter quite a + + + align:start position:0% +but what really seems to matter quite a +bit is the type of contact that people + + align:start position:0% +bit is the type of contact that people + + + align:start position:0% +bit is the type of contact that people +are + + align:start position:0% +are + + + align:start position:0% +are +exposed to okay so finally + + align:start position:0% +exposed to okay so finally + + + align:start position:0% +exposed to okay so finally +and relatively quickly i'll tell you a + + align:start position:0% +and relatively quickly i'll tell you a + + + align:start position:0% +and relatively quickly i'll tell you a +little bit about whether people + + align:start position:0% +little bit about whether people + + + align:start position:0% +little bit about whether people +underestimate the benefits of + + align:start position:0% +underestimate the benefits of + + + align:start position:0% +underestimate the benefits of +post-sociality i should mention that + + align:start position:0% +post-sociality i should mention that + + + align:start position:0% +post-sociality i should mention that +problem set three question two is in + + align:start position:0% +problem set three question two is in + + + align:start position:0% +problem set three question two is in +fact + + align:start position:0% +fact + + + align:start position:0% +fact +trying to ask you to do something + + align:start position:0% +trying to ask you to do something + + + align:start position:0% +trying to ask you to do something +related to that so you might want to + + align:start position:0% +related to that so you might want to + + + align:start position:0% +related to that so you might want to +actually do the problems at first before + + align:start position:0% +actually do the problems at first before + + + align:start position:0% +actually do the problems at first before +you finish this lecture + + align:start position:0% +you finish this lecture + + + align:start position:0% +you finish this lecture +uh at least sort of sorry not the entire + + align:start position:0% +uh at least sort of sorry not the entire + + + align:start position:0% +uh at least sort of sorry not the entire +problem set but like question two + + align:start position:0% +problem set but like question two + + + align:start position:0% +problem set but like question two +of problem set three um that will not + + align:start position:0% +of problem set three um that will not + + + align:start position:0% +of problem set three um that will not +take you + + align:start position:0% +take you + + + align:start position:0% +take you +very long um um uh to do so and it's + + align:start position:0% +very long um um uh to do so and it's + + + align:start position:0% +very long um um uh to do so and it's +more like a fun + + align:start position:0% +more like a fun + + + align:start position:0% +more like a fun +exercise that i thought would be nice + + align:start position:0% +exercise that i thought would be nice + + + align:start position:0% +exercise that i thought would be nice +for you to uh to engage in + + align:start position:0% +for you to uh to engage in + + + align:start position:0% +for you to uh to engage in +but anyway um this is a very nice paper + + align:start position:0% +but anyway um this is a very nice paper + + + align:start position:0% +but anyway um this is a very nice paper +by + + align:start position:0% +by + + + align:start position:0% +by +kumar and epley so that's a typo here i + + align:start position:0% +kumar and epley so that's a typo here i + + + align:start position:0% +kumar and epley so that's a typo here i +should say + + align:start position:0% +should say + + + align:start position:0% +should say +kumar neplay and the authors asked the + + align:start position:0% +kumar neplay and the authors asked the + + + align:start position:0% +kumar neplay and the authors asked the +question about + + align:start position:0% +question about + + + align:start position:0% +question about +do we have correct beliefs about the + + align:start position:0% +do we have correct beliefs about the + + + align:start position:0% +do we have correct beliefs about the +impacts of generosity + + align:start position:0% +impacts of generosity + + + align:start position:0% +impacts of generosity +and so what's the underlying reason here + + align:start position:0% +and so what's the underlying reason here + + + align:start position:0% +and so what's the underlying reason here +is well many pro-social acts require + + align:start position:0% +is well many pro-social acts require + + + align:start position:0% +is well many pro-social acts require +estimating the impacts on the recipient + + align:start position:0% +estimating the impacts on the recipient + + + align:start position:0% +estimating the impacts on the recipient +but if you give money to somebody in + + align:start position:0% +but if you give money to somebody in + + + align:start position:0% +but if you give money to somebody in +africa if you + + align:start position:0% +africa if you + + + align:start position:0% +africa if you +help anybody any people in need if you + + align:start position:0% +help anybody any people in need if you + + + align:start position:0% +help anybody any people in need if you +donate money in general if you + + align:start position:0% +donate money in general if you + + + align:start position:0% +donate money in general if you +like write letters of gratitude or if + + align:start position:0% +like write letters of gratitude or if + + + align:start position:0% +like write letters of gratitude or if +you do random acts of kindness + + align:start position:0% +you do random acts of kindness + + + align:start position:0% +you do random acts of kindness +it requires some sort of estimation of + + align:start position:0% +it requires some sort of estimation of + + + align:start position:0% +it requires some sort of estimation of +how is the other person going to feel + + align:start position:0% +how is the other person going to feel + + + align:start position:0% +how is the other person going to feel +if they receive uh if they're on the + + align:start position:0% +if they receive uh if they're on the + + + align:start position:0% +if they receive uh if they're on the +receiving end of this pro-social act + + align:start position:0% +receiving end of this pro-social act + + + align:start position:0% +receiving end of this pro-social act +now what eppley and kumar argue is + + align:start position:0% +now what eppley and kumar argue is + + + align:start position:0% +now what eppley and kumar argue is +people are + + align:start position:0% +people are + + + align:start position:0% +people are +subject to egocentric bias which may + + align:start position:0% +subject to egocentric bias which may + + + align:start position:0% +subject to egocentric bias which may +lead them + + align:start position:0% +lead them + + + align:start position:0% +lead them +to systematically underestimate the + + align:start position:0% +to systematically underestimate the + + + align:start position:0% +to systematically underestimate the +positive impacts of pro-sociology in + + align:start position:0% +positive impacts of pro-sociology in + + + align:start position:0% +positive impacts of pro-sociology in +this case + + align:start position:0% +this case + + + align:start position:0% +this case +gratitude letters and so why is that + + align:start position:0% +gratitude letters and so why is that + + + align:start position:0% +gratitude letters and so why is that +well it's because predicting others + + align:start position:0% +well it's because predicting others + + + align:start position:0% +well it's because predicting others +mental states is different + + align:start position:0% +mental states is different + + + align:start position:0% +mental states is different +difficult it's really hard to um + + align:start position:0% +difficult it's really hard to um + + + align:start position:0% +difficult it's really hard to um +for people to understand how another + + align:start position:0% +for people to understand how another + + + align:start position:0% +for people to understand how another +person might feel + + align:start position:0% +person might feel + + + align:start position:0% +person might feel +usually people would sort of think about + + align:start position:0% +usually people would sort of think about + + + align:start position:0% +usually people would sort of think about +themselves and sort of think about how + + align:start position:0% +themselves and sort of think about how + + + align:start position:0% +themselves and sort of think about how +would i feel and then what + + align:start position:0% +would i feel and then what + + + align:start position:0% +would i feel and then what +what would things be and how are things + + align:start position:0% +what would things be and how are things + + + align:start position:0% +what would things be and how are things +like and and it's very hard to + + align:start position:0% +like and and it's very hard to + + + align:start position:0% +like and and it's very hard to +understand + + align:start position:0% +understand + + + align:start position:0% +understand +uh how others might react to you + + align:start position:0% +uh how others might react to you + + + align:start position:0% +uh how others might react to you +it sort of requires perspective taking + + align:start position:0% +it sort of requires perspective taking + + + align:start position:0% +it sort of requires perspective taking +and that's sometimes + + align:start position:0% +and that's sometimes + + + align:start position:0% +and that's sometimes +tricky for people um to do so this is + + align:start position:0% +tricky for people um to do so this is + + + align:start position:0% +tricky for people um to do so this is +again um a very nice experiment by um + + align:start position:0% +again um a very nice experiment by um + + + align:start position:0% +again um a very nice experiment by um +kumar and nicolas apley not + + align:start position:0% +kumar and nicolas apley not + + + align:start position:0% +kumar and nicolas apley not +not nicolas last name but nick appley + + align:start position:0% +not nicolas last name but nick appley + + + align:start position:0% +not nicolas last name but nick appley +and they test whether people + + align:start position:0% +and they test whether people + + + align:start position:0% +and they test whether people +misunderstand the cause + + align:start position:0% +misunderstand the cause + + + align:start position:0% +misunderstand the cause +the consequences of showing appreciation + + align:start position:0% +the consequences of showing appreciation + + + align:start position:0% +the consequences of showing appreciation +and so what are these + + align:start position:0% +and so what are these + + + align:start position:0% +and so what are these +experiments there's a series of + + align:start position:0% +experiments there's a series of + + + align:start position:0% +experiments there's a series of +experiments that look at this what do + + align:start position:0% +experiments that look at this what do + + + align:start position:0% +experiments that look at this what do +they look like + + align:start position:0% +they look like + + + align:start position:0% +they look like +but what what they do is like they ask + + align:start position:0% +but what what they do is like they ask + + + align:start position:0% +but what what they do is like they ask +people uh + + align:start position:0% +people uh + + + align:start position:0% +people uh +mba students or subjects and expert + + align:start position:0% +mba students or subjects and expert + + + align:start position:0% +mba students or subjects and expert +subjects and experiments + + align:start position:0% +subjects and experiments + + + align:start position:0% +subjects and experiments +to pick a pro-social act that's writing + + align:start position:0% +to pick a pro-social act that's writing + + + align:start position:0% +to pick a pro-social act that's writing +a gratitude letter for example + + align:start position:0% +a gratitude letter for example + + + align:start position:0% +a gratitude letter for example +and then ask how the giver and the + + align:start position:0% +and then ask how the giver and the + + + align:start position:0% +and then ask how the giver and the +recipient will be affected + + align:start position:0% +recipient will be affected + + + align:start position:0% +recipient will be affected +in some cases only the recipient in some + + align:start position:0% +in some cases only the recipient in some + + + align:start position:0% +in some cases only the recipient in some +cases also + + align:start position:0% +cases also + + + align:start position:0% +cases also +the giver then they perform the + + align:start position:0% +the giver then they perform the + + + align:start position:0% +the giver then they perform the +pro-social act + + align:start position:0% +pro-social act + + + align:start position:0% +pro-social act +by for example writing a letter of + + align:start position:0% +by for example writing a letter of + + + align:start position:0% +by for example writing a letter of +gratitude and then assess how the giver + + align:start position:0% +gratitude and then assess how the giver + + + align:start position:0% +gratitude and then assess how the giver +and the recipients were actually + + align:start position:0% +and the recipients were actually + + + align:start position:0% +and the recipients were actually +affected by + + align:start position:0% +affected by + + + align:start position:0% +affected by +doing that and then you can compare that + + align:start position:0% +doing that and then you can compare that + + + align:start position:0% +doing that and then you can compare that +to item number two to the estimation + + align:start position:0% +to item number two to the estimation + + + align:start position:0% +to item number two to the estimation +ex-ante now what do they find + + align:start position:0% +ex-ante now what do they find + + + align:start position:0% +ex-ante now what do they find +they find uh clear evidence that when + + align:start position:0% +they find uh clear evidence that when + + + align:start position:0% +they find uh clear evidence that when +you look at like in particular when you + + align:start position:0% +you look at like in particular when you + + + align:start position:0% +you look at like in particular when you +look at the giver + + align:start position:0% +look at the giver + + + align:start position:0% +look at the giver +so these um graphs all show kind of like + + align:start position:0% +so these um graphs all show kind of like + + + align:start position:0% +so these um graphs all show kind of like +the predicted + + align:start position:0% +the predicted + + + align:start position:0% +the predicted +uh ratings the ratings is between zero + + align:start position:0% +uh ratings the ratings is between zero + + + align:start position:0% +uh ratings the ratings is between zero +and ten um + + align:start position:0% +and ten um + + + align:start position:0% +and ten um +about like um how um uh what's the + + align:start position:0% +about like um how um uh what's the + + + align:start position:0% +about like um how um uh what's the +experience how happy is the other person + + align:start position:0% +experience how happy is the other person + + + align:start position:0% +experience how happy is the other person +uh what is the surprise about receiving + + align:start position:0% +uh what is the surprise about receiving + + + align:start position:0% +uh what is the surprise about receiving +um + + align:start position:0% +um + + + align:start position:0% +um +uh this letter of gratitude in this + + align:start position:0% +uh this letter of gratitude in this + + + align:start position:0% +uh this letter of gratitude in this +example so people are more surprised + + align:start position:0% +example so people are more surprised + + + align:start position:0% +example so people are more surprised +than predicted + + align:start position:0% +than predicted + + + align:start position:0% +than predicted +they're also more surprised about the + + align:start position:0% +they're also more surprised about the + + + align:start position:0% +they're also more surprised about the +content than pre + + align:start position:0% +content than pre + + + align:start position:0% +content than pre +predicted um they also uh the + + align:start position:0% +predicted um they also uh the + + + align:start position:0% +predicted um they also uh the +recipient's mood is actually + + align:start position:0% +recipient's mood is actually + + + align:start position:0% +recipient's mood is actually +better than predicted and uh the + + align:start position:0% +better than predicted and uh the + + + align:start position:0% +better than predicted and uh the +awkwardness is also + + align:start position:0% +awkwardness is also + + + align:start position:0% +awkwardness is also +um better than predicted so when you ask + + align:start position:0% +um better than predicted so when you ask + + + align:start position:0% +um better than predicted so when you ask +people to write like letters of + + align:start position:0% +people to write like letters of + + + align:start position:0% +people to write like letters of +gratitude + + align:start position:0% +gratitude + + + align:start position:0% +gratitude +people tend to say oh you know like uh + + align:start position:0% +people tend to say oh you know like uh + + + align:start position:0% +people tend to say oh you know like uh +it's going to be like tedious to do + + align:start position:0% +it's going to be like tedious to do + + + align:start position:0% +it's going to be like tedious to do +and like um the other person might feel + + align:start position:0% +and like um the other person might feel + + + align:start position:0% +and like um the other person might feel +it's + + align:start position:0% +it's + + + align:start position:0% +it's +awkward and what am i going to say and + + align:start position:0% +awkward and what am i going to say and + + + align:start position:0% +awkward and what am i going to say and +is it going to be weird what i'm going + + align:start position:0% +is it going to be weird what i'm going + + + align:start position:0% +is it going to be weird what i'm going +to say + + align:start position:0% +to say + + + align:start position:0% +to say +is the person they do don't they know + + align:start position:0% +is the person they do don't they know + + + align:start position:0% +is the person they do don't they know +already anyway that i'm + + align:start position:0% +already anyway that i'm + + + align:start position:0% +already anyway that i'm +really appreciate off that person and so + + align:start position:0% +really appreciate off that person and so + + + align:start position:0% +really appreciate off that person and so +on so um + + align:start position:0% +on so um + + + align:start position:0% +on so um +people come up with all sorts of reasons + + align:start position:0% +people come up with all sorts of reasons + + + align:start position:0% +people come up with all sorts of reasons +why they might not want to do that + + align:start position:0% +why they might not want to do that + + + align:start position:0% +why they might not want to do that +if you sort of introspect and ask + + align:start position:0% +if you sort of introspect and ask + + + align:start position:0% +if you sort of introspect and ask +yourself how many letters of gratitude + + align:start position:0% +yourself how many letters of gratitude + + + align:start position:0% +yourself how many letters of gratitude +have you written in the last year + + align:start position:0% +have you written in the last year + + + align:start position:0% +have you written in the last year +that doesn't few people actually do that + + align:start position:0% +that doesn't few people actually do that + + + align:start position:0% +that doesn't few people actually do that +in practice + + align:start position:0% +in practice + + + align:start position:0% +in practice +and perhaps some of these reasons like + + align:start position:0% +and perhaps some of these reasons like + + + align:start position:0% +and perhaps some of these reasons like +the perceived awkwardness or perhaps + + align:start position:0% +the perceived awkwardness or perhaps + + + align:start position:0% +the perceived awkwardness or perhaps +sort of the underestimation of + + align:start position:0% +sort of the underestimation of + + + align:start position:0% +sort of the underestimation of +the recipient's mood might contribute to + + align:start position:0% +the recipient's mood might contribute to + + + align:start position:0% +the recipient's mood might contribute to +that now if you also think for a little + + align:start position:0% +that now if you also think for a little + + + align:start position:0% +that now if you also think for a little +bit like + + align:start position:0% +bit like + + + align:start position:0% +bit like +uh how would one actually feel to + + align:start position:0% +uh how would one actually feel to + + + align:start position:0% +uh how would one actually feel to +receive these letters it's pretty + + align:start position:0% +receive these letters it's pretty + + + align:start position:0% +receive these letters it's pretty +obvious once you think about it that + + align:start position:0% +obvious once you think about it that + + + align:start position:0% +obvious once you think about it that +most people are actually quite happy + + align:start position:0% +most people are actually quite happy + + + align:start position:0% +most people are actually quite happy +about receiving such letters it's kind + + align:start position:0% +about receiving such letters it's kind + + + align:start position:0% +about receiving such letters it's kind +of nice if somebody + + align:start position:0% +of nice if somebody + + + align:start position:0% +of nice if somebody +tells you look you did something really + + align:start position:0% +tells you look you did something really + + + align:start position:0% +tells you look you did something really +nice for me sometime + + align:start position:0% +nice for me sometime + + + align:start position:0% +nice for me sometime +like a long time ago and you know this + + align:start position:0% +like a long time ago and you know this + + + align:start position:0% +like a long time ago and you know this +helped me a lot in my career and + + align:start position:0% +helped me a lot in my career and + + + align:start position:0% +helped me a lot in my career and +whatever ways or like in + + align:start position:0% +whatever ways or like in + + + align:start position:0% +whatever ways or like in +in getting into school into like college + + align:start position:0% +in getting into school into like college + + + align:start position:0% +in getting into school into like college +or whatever it might be + + align:start position:0% +or whatever it might be + + + align:start position:0% +or whatever it might be +it's really nice to sort of hear from + + align:start position:0% +it's really nice to sort of hear from + + + align:start position:0% +it's really nice to sort of hear from +somebody that um you did something nice + + align:start position:0% +somebody that um you did something nice + + + align:start position:0% +somebody that um you did something nice +in their life + + align:start position:0% +in their life + + + align:start position:0% +in their life +that people are quite um uh happy about + + align:start position:0% +that people are quite um uh happy about + + + align:start position:0% +that people are quite um uh happy about +now what sort of like um some evidence + + align:start position:0% +now what sort of like um some evidence + + + align:start position:0% +now what sort of like um some evidence +uh + + align:start position:0% +uh + + + align:start position:0% +uh +some summary of that well so we tend to + + align:start position:0% +some summary of that well so we tend to + + + align:start position:0% +some summary of that well so we tend to +systematically underestimate + + align:start position:0% +systematically underestimate + + + align:start position:0% +systematically underestimate +others appreciations in expressions of + + align:start position:0% +others appreciations in expressions of + + + align:start position:0% +others appreciations in expressions of +gratitude + + align:start position:0% +gratitude + + + align:start position:0% +gratitude +that's also true for some other types of + + align:start position:0% +that's also true for some other types of + + + align:start position:0% +that's also true for some other types of +effects that tends to be also true for + + align:start position:0% +effects that tends to be also true for + + + align:start position:0% +effects that tends to be also true for +like + + align:start position:0% +like + + + align:start position:0% +like +random acts of kindness people tend to + + align:start position:0% +random acts of kindness people tend to + + + align:start position:0% +random acts of kindness people tend to +be surprisingly more + + align:start position:0% +be surprisingly more + + + align:start position:0% +be surprisingly more +happy about those compared to predicted + + align:start position:0% +happy about those compared to predicted + + + align:start position:0% +happy about those compared to predicted +it's also true so apple and schroeder + + align:start position:0% +it's also true so apple and schroeder + + + align:start position:0% +it's also true so apple and schroeder +argue um + + align:start position:0% +argue um + + + align:start position:0% +argue um +for social connections so people also + + align:start position:0% +for social connections so people also + + + align:start position:0% +for social connections so people also +underestimate on average + + align:start position:0% +underestimate on average + + + align:start position:0% +underestimate on average +how they themselves and other feel when + + align:start position:0% +how they themselves and other feel when + + + align:start position:0% +how they themselves and other feel when +starting conversations so what this + + align:start position:0% +starting conversations so what this + + + align:start position:0% +starting conversations so what this +experiment does is it gets people to + + align:start position:0% +experiment does is it gets people to + + + align:start position:0% +experiment does is it gets people to +adrenalize as people to + + align:start position:0% +adrenalize as people to + + + align:start position:0% +adrenalize as people to +start conversations during commuting on + + align:start position:0% +start conversations during commuting on + + + align:start position:0% +start conversations during commuting on +buses or trains + + align:start position:0% +buses or trains + + + align:start position:0% +buses or trains +and once people start doing that again + + align:start position:0% +and once people start doing that again + + + align:start position:0% +and once people start doing that again +before when you ask them like you know + + align:start position:0% +before when you ask them like you know + + + align:start position:0% +before when you ask them like you know +how is the other person going to feel + + align:start position:0% +how is the other person going to feel + + + align:start position:0% +how is the other person going to feel +how are you going to feel and so on + + align:start position:0% +how are you going to feel and so on + + + align:start position:0% +how are you going to feel and so on +people will say well it's gonna be + + align:start position:0% +people will say well it's gonna be + + + align:start position:0% +people will say well it's gonna be +awkward and like what are we gonna talk + + align:start position:0% +awkward and like what are we gonna talk + + + align:start position:0% +awkward and like what are we gonna talk +about + + align:start position:0% +about + + + align:start position:0% +about +and is the other person even interested + + align:start position:0% +and is the other person even interested + + + align:start position:0% +and is the other person even interested +and so on um but once you actually do + + align:start position:0% +and so on um but once you actually do + + + align:start position:0% +and so on um but once you actually do +that people + + align:start position:0% +that people + + + align:start position:0% +that people +seem to be quite happy to have started + + align:start position:0% +seem to be quite happy to have started + + + align:start position:0% +seem to be quite happy to have started +conversations so making human um + + align:start position:0% +conversations so making human um + + + align:start position:0% +conversations so making human um +connection to be clear not everybody is + + align:start position:0% +connection to be clear not everybody is + + + align:start position:0% +connection to be clear not everybody is +happy some people might be also grumpy + + align:start position:0% +happy some people might be also grumpy + + + align:start position:0% +happy some people might be also grumpy +but the vast majority at least in these + + align:start position:0% +but the vast majority at least in these + + + align:start position:0% +but the vast majority at least in these +types of study + + align:start position:0% +types of study + + + align:start position:0% +types of study +seem to be quite happy about uh + + align:start position:0% +seem to be quite happy about uh + + + align:start position:0% +seem to be quite happy about uh +initiating social contact + + align:start position:0% +initiating social contact + + + align:start position:0% +initiating social contact +about uh expressions letters of + + align:start position:0% +about uh expressions letters of + + + align:start position:0% +about uh expressions letters of +gratitude uh + + align:start position:0% +gratitude uh + + + align:start position:0% +gratitude uh +or things like random acts of kindness + + align:start position:0% +or things like random acts of kindness + + + align:start position:0% +or things like random acts of kindness +it's really nice if somebody happens to + + align:start position:0% +it's really nice if somebody happens to + + + align:start position:0% +it's really nice if somebody happens to +be something to do something nice + + align:start position:0% +be something to do something nice + + + align:start position:0% +be something to do something nice +towards you it could be like a random + + align:start position:0% +towards you it could be like a random + + + align:start position:0% +towards you it could be like a random +person who you've never + + align:start position:0% +person who you've never + + + align:start position:0% +person who you've never +seen before and you never see again just + + align:start position:0% +seen before and you never see again just + + + align:start position:0% +seen before and you never see again just +some random person on the street is + + align:start position:0% +some random person on the street is + + + align:start position:0% +some random person on the street is +really nice to you + + align:start position:0% +really nice to you + + + align:start position:0% +really nice to you +that might make you day it could be also + + align:start position:0% +that might make you day it could be also + + + align:start position:0% +that might make you day it could be also +somebody who + + align:start position:0% +somebody who + + + align:start position:0% +somebody who +um you know quite well and he's a good + + align:start position:0% +um you know quite well and he's a good + + + align:start position:0% +um you know quite well and he's a good +friend and uh uh + + align:start position:0% +friend and uh uh + + + align:start position:0% +friend and uh uh +who just wants to do something nice uh + + align:start position:0% +who just wants to do something nice uh + + + align:start position:0% +who just wants to do something nice uh +for you for no good apparent reasons + + align:start position:0% +for you for no good apparent reasons + + + align:start position:0% +for you for no good apparent reasons +so one caveat to these kinds of + + align:start position:0% +so one caveat to these kinds of + + + align:start position:0% +so one caveat to these kinds of +experiments is these are very much like + + align:start position:0% +experiments is these are very much like + + + align:start position:0% +experiments is these are very much like +one short + + align:start position:0% +one short + + + align:start position:0% +one short +one short short interactions these are + + align:start position:0% +one short short interactions these are + + + align:start position:0% +one short short interactions these are +one-time interactions and then the + + align:start position:0% +one-time interactions and then the + + + align:start position:0% +one-time interactions and then the +effects are measured + + align:start position:0% +effects are measured + + + align:start position:0% +effects are measured +so there are some questions about do + + align:start position:0% +so there are some questions about do + + + align:start position:0% +so there are some questions about do +these effects persist for repeat + + align:start position:0% +these effects persist for repeat + + + align:start position:0% +these effects persist for repeat +interactions + + align:start position:0% +interactions + + + align:start position:0% +interactions +that is to say like maybe if you do that + + align:start position:0% +that is to say like maybe if you do that + + + align:start position:0% +that is to say like maybe if you do that +once people are quite happy + + align:start position:0% +once people are quite happy + + + align:start position:0% +once people are quite happy +but when you try it more often these + + align:start position:0% +but when you try it more often these + + + align:start position:0% +but when you try it more often these +effects tend to go away + + align:start position:0% +effects tend to go away + + + align:start position:0% +effects tend to go away +so there's a bit of a question kind of + + align:start position:0% +so there's a bit of a question kind of + + + align:start position:0% +so there's a bit of a question kind of +like how persistent how important are + + align:start position:0% +like how persistent how important are + + + align:start position:0% +like how persistent how important are +these in practice if you do that more + + align:start position:0% +these in practice if you do that more + + + align:start position:0% +these in practice if you do that more +often + + align:start position:0% +often + + + align:start position:0% +often +in particular in the long run and then + + align:start position:0% +in particular in the long run and then + + + align:start position:0% +in particular in the long run and then +another + + align:start position:0% +another + + + align:start position:0% +another +important question here is then the + + align:start position:0% +important question here is then the + + + align:start position:0% +important question here is then the +question about is are we + + align:start position:0% +question about is are we + + + align:start position:0% +question about is are we +under investing in pro-sociality in + + align:start position:0% +under investing in pro-sociality in + + + align:start position:0% +under investing in pro-sociality in +terms of our behavior + + align:start position:0% +terms of our behavior + + + align:start position:0% +terms of our behavior +so lots of people who tend to be quite + + align:start position:0% +so lots of people who tend to be quite + + + align:start position:0% +so lots of people who tend to be quite +um + + align:start position:0% +um + + + align:start position:0% +um +selfish and sort of do good things for + + align:start position:0% +selfish and sort of do good things for + + + align:start position:0% +selfish and sort of do good things for +themselves and not so much for others + + align:start position:0% +themselves and not so much for others + + + align:start position:0% +themselves and not so much for others +presumably they do that because they + + align:start position:0% +presumably they do that because they + + + align:start position:0% +presumably they do that because they +want to make themselves happy presumably + + align:start position:0% +want to make themselves happy presumably + + + align:start position:0% +want to make themselves happy presumably +people who do nice things towards others + + align:start position:0% +people who do nice things towards others + + + align:start position:0% +people who do nice things towards others +to some degree + + align:start position:0% +to some degree + + + align:start position:0% +to some degree +do that because they want to make the + + align:start position:0% +do that because they want to make the + + + align:start position:0% +do that because they want to make the +other person happy in part perhaps + + align:start position:0% +other person happy in part perhaps + + + align:start position:0% +other person happy in part perhaps +because because of social image and + + align:start position:0% +because because of social image and + + + align:start position:0% +because because of social image and +self-image concerns but one important + + align:start position:0% +self-image concerns but one important + + + align:start position:0% +self-image concerns but one important +hypothesis that eppley and others + + align:start position:0% +hypothesis that eppley and others + + + align:start position:0% +hypothesis that eppley and others +raises the question of like well i'll be + + align:start position:0% +raises the question of like well i'll be + + + align:start position:0% +raises the question of like well i'll be +underestimating + + align:start position:0% +underestimating + + + align:start position:0% +underestimating +how good it might not only make others + + align:start position:0% +how good it might not only make others + + + align:start position:0% +how good it might not only make others +feel but also ourselves feel from being + + align:start position:0% +feel but also ourselves feel from being + + + align:start position:0% +feel but also ourselves feel from being +nice + + align:start position:0% +nice + + + align:start position:0% +nice +that is to say perhaps one easy way of + + align:start position:0% +that is to say perhaps one easy way of + + + align:start position:0% +that is to say perhaps one easy way of +making ourselves happy + + align:start position:0% +making ourselves happy + + + align:start position:0% +making ourselves happy +is not just by being selfish and + + align:start position:0% +is not just by being selfish and + + + align:start position:0% +is not just by being selfish and +maximizing whatever + + align:start position:0% +maximizing whatever + + + align:start position:0% +maximizing whatever +outcomes we get but be really being nice + + align:start position:0% +outcomes we get but be really being nice + + + align:start position:0% +outcomes we get but be really being nice +towards others + + align:start position:0% +towards others + + + align:start position:0% +towards others +in part perhaps because it just makes us + + align:start position:0% +in part perhaps because it just makes us + + + align:start position:0% +in part perhaps because it just makes us +happy to see when others are happy + + align:start position:0% +happy to see when others are happy + + + align:start position:0% +happy to see when others are happy +perhaps it makes us happy because you + + align:start position:0% +perhaps it makes us happy because you + + + align:start position:0% +perhaps it makes us happy because you +know others will be the nicer toss + + align:start position:0% +know others will be the nicer toss + + + align:start position:0% +know others will be the nicer toss +and there's a question about can we make + + align:start position:0% +and there's a question about can we make + + + align:start position:0% +and there's a question about can we make +others and + + align:start position:0% +others and + + + align:start position:0% +others and +ourselves happier by being more + + align:start position:0% +ourselves happier by being more + + + align:start position:0% +ourselves happier by being more +pro-social + + align:start position:0% +pro-social + + + align:start position:0% +pro-social +perhaps um because we underestimate uh + + align:start position:0% +perhaps um because we underestimate uh + + + align:start position:0% +perhaps um because we underestimate uh +uh to start with + + align:start position:0% +uh to start with + + + align:start position:0% +uh to start with +uh what these effects um might be uh i + + align:start position:0% +uh what these effects um might be uh i + + + align:start position:0% +uh what these effects um might be uh i +don't think there's that much evidence + + align:start position:0% +don't think there's that much evidence + + + align:start position:0% +don't think there's that much evidence +on on this specific question but i'd + + align:start position:0% +on on this specific question but i'd + + + align:start position:0% +on on this specific question but i'd +love to uh learn more and when you think + + align:start position:0% +love to uh learn more and when you think + + + align:start position:0% +love to uh learn more and when you think +about like your own life + + align:start position:0% +about like your own life + + + align:start position:0% +about like your own life +you might wanna experiment uh uh for a + + align:start position:0% +you might wanna experiment uh uh for a + + + align:start position:0% +you might wanna experiment uh uh for a +while and seeing like + + align:start position:0% +while and seeing like + + + align:start position:0% +while and seeing like +um trying to be nicer trying to uh uh + + align:start position:0% +um trying to be nicer trying to uh uh + + + align:start position:0% +um trying to be nicer trying to uh uh +engage in random acts of kindness + + align:start position:0% +engage in random acts of kindness + + + align:start position:0% +engage in random acts of kindness +letters of gratitude + + align:start position:0% +letters of gratitude + + + align:start position:0% +letters of gratitude +and gratitude and so on that might be a + + align:start position:0% +and gratitude and so on that might be a + + + align:start position:0% +and gratitude and so on that might be a +nice habit to acquire + + align:start position:0% +nice habit to acquire + + + align:start position:0% +nice habit to acquire +and you might see it might may and might + + align:start position:0% +and you might see it might may and might + + + align:start position:0% +and you might see it might may and might +make you uh happier + + align:start position:0% +make you uh happier + + + align:start position:0% +make you uh happier +surely it will make the other person on + + align:start position:0% +surely it will make the other person on + + + align:start position:0% +surely it will make the other person on +the receiving end happier + + align:start position:0% +the receiving end happier + + + align:start position:0% +the receiving end happier +okay so let me sort of summarize what we + + align:start position:0% +okay so let me sort of summarize what we + + + align:start position:0% +okay so let me sort of summarize what we +learned + + align:start position:0% +learned + + + align:start position:0% +learned +what we studied on social preferences so + + align:start position:0% +what we studied on social preferences so + + + align:start position:0% +what we studied on social preferences so +first others outcomes and utility matter + + align:start position:0% +first others outcomes and utility matter + + + align:start position:0% +first others outcomes and utility matter +for people's choices quite a bit + + align:start position:0% +for people's choices quite a bit + + + align:start position:0% +for people's choices quite a bit +so in their situation essentially people + + align:start position:0% +so in their situation essentially people + + + align:start position:0% +so in their situation essentially people +are willing to give to others and + + align:start position:0% +are willing to give to others and + + + align:start position:0% +are willing to give to others and +they're influenced by others + + align:start position:0% +they're influenced by others + + + align:start position:0% +they're influenced by others +in their choices now upon closer look + + align:start position:0% +in their choices now upon closer look + + + align:start position:0% +in their choices now upon closer look +there's not much evidence of pure + + align:start position:0% +there's not much evidence of pure + + + align:start position:0% +there's not much evidence of pure +altruism rarely does it seem that people + + align:start position:0% +altruism rarely does it seem that people + + + align:start position:0% +altruism rarely does it seem that people +just do stuff for others + + align:start position:0% +just do stuff for others + + + align:start position:0% +just do stuff for others +just for the sake of others doing well + + align:start position:0% +just for the sake of others doing well + + + align:start position:0% +just for the sake of others doing well +and that is to say like if people get + + align:start position:0% +and that is to say like if people get + + + align:start position:0% +and that is to say like if people get +the chance of like + + align:start position:0% +the chance of like + + + align:start position:0% +the chance of like +hiding their not so nice actions they + + align:start position:0% +hiding their not so nice actions they + + + align:start position:0% +hiding their not so nice actions they +will often take advantage of that + + align:start position:0% +will often take advantage of that + + + align:start position:0% +will often take advantage of that +the motivation there often is uh instead + + align:start position:0% +the motivation there often is uh instead + + + align:start position:0% +the motivation there often is uh instead +motivation to give to others or be nice + + align:start position:0% +motivation to give to others or be nice + + + align:start position:0% +motivation to give to others or be nice +to others to be pro-social + + align:start position:0% +to others to be pro-social + + + align:start position:0% +to others to be pro-social +is often saving face in front of others + + align:start position:0% +is often saving face in front of others + + + align:start position:0% +is often saving face in front of others +this is social image + + align:start position:0% +this is social image + + + align:start position:0% +this is social image +or themselves which is um self-image + + align:start position:0% +or themselves which is um self-image + + + align:start position:0% +or themselves which is um self-image +so here are so and because of that + + align:start position:0% +so here are so and because of that + + + align:start position:0% +so here are so and because of that +situational circumstances matter greatly + + align:start position:0% +situational circumstances matter greatly + + + align:start position:0% +situational circumstances matter greatly +societal norms are + + align:start position:0% +societal norms are + + + align:start position:0% +societal norms are +are really important to consider so when + + align:start position:0% +are really important to consider so when + + + align:start position:0% +are really important to consider so when +you think about like incentives or any + + align:start position:0% +you think about like incentives or any + + + align:start position:0% +you think about like incentives or any +sort of types of structures and + + align:start position:0% +sort of types of structures and + + + align:start position:0% +sort of types of structures and +organizations + + align:start position:0% +organizations + + + align:start position:0% +organizations +how might you um set incentives or how + + align:start position:0% +how might you um set incentives or how + + + align:start position:0% +how might you um set incentives or how +might we sort of + + align:start position:0% +might we sort of + + + align:start position:0% +might we sort of +structure certain groups or people + + align:start position:0% +structure certain groups or people + + + align:start position:0% +structure certain groups or people +working together + + align:start position:0% +working together + + + align:start position:0% +working together +understanding these norms and + + align:start position:0% +understanding these norms and + + + align:start position:0% +understanding these norms and +circumstances is key for fostering + + align:start position:0% +circumstances is key for fostering + + + align:start position:0% +circumstances is key for fostering +pro-sociology + + align:start position:0% +pro-sociology + + + align:start position:0% +pro-sociology +if you want people to be nice to each + + align:start position:0% +if you want people to be nice to each + + + align:start position:0% +if you want people to be nice to each +other you have to set it up in a way + + align:start position:0% +other you have to set it up in a way + + + align:start position:0% +other you have to set it up in a way +that it's maybe um + + align:start position:0% +that it's maybe um + + + align:start position:0% +that it's maybe um +observable what people do it's + + align:start position:0% +observable what people do it's + + + align:start position:0% +observable what people do it's +encouraged there's + + align:start position:0% +encouraged there's + + + align:start position:0% +encouraged there's +opportunities for reciprocity and so on + + align:start position:0% +opportunities for reciprocity and so on + + + align:start position:0% +opportunities for reciprocity and so on +so a lot of the design of society of + + align:start position:0% +so a lot of the design of society of + + + align:start position:0% +so a lot of the design of society of +like a firm of a group that you work in + + align:start position:0% +like a firm of a group that you work in + + + align:start position:0% +like a firm of a group that you work in +or a team that you work in really seems + + align:start position:0% +or a team that you work in really seems + + + align:start position:0% +or a team that you work in really seems +to matter + + align:start position:0% +to matter + + + align:start position:0% +to matter +so on the one hand as i said before it's + + align:start position:0% +so on the one hand as i said before it's + + + align:start position:0% +so on the one hand as i said before it's +a little bit disappointing that there's + + align:start position:0% +a little bit disappointing that there's + + + align:start position:0% +a little bit disappointing that there's +not much + + align:start position:0% +not much + + + align:start position:0% +not much +pure altruism but on the other hand if + + align:start position:0% +pure altruism but on the other hand if + + + align:start position:0% +pure altruism but on the other hand if +you sort of understand + + align:start position:0% +you sort of understand + + + align:start position:0% +you sort of understand +the motivations poor for people being to + + align:start position:0% +the motivations poor for people being to + + + align:start position:0% +the motivations poor for people being to +engage in + + align:start position:0% +engage in + + + align:start position:0% +engage in +acts that are good for others we can + + align:start position:0% +acts that are good for others we can + + + align:start position:0% +acts that are good for others we can +sort of design + + align:start position:0% +sort of design + + + align:start position:0% +sort of design +uh incentives and structures that people + + align:start position:0% +uh incentives and structures that people + + + align:start position:0% +uh incentives and structures that people +work in accordingly + + align:start position:0% +work in accordingly + + + align:start position:0% +work in accordingly +which will then create people being + + align:start position:0% +which will then create people being + + + align:start position:0% +which will then create people being +friendly and cooperative + + align:start position:0% +friendly and cooperative + + + align:start position:0% +friendly and cooperative +to each other second i showed you that + + align:start position:0% +to each other second i showed you that + + + align:start position:0% +to each other second i showed you that +social preferences matter at workplaces + + align:start position:0% +social preferences matter at workplaces + + + align:start position:0% +social preferences matter at workplaces +um relative pay can depress incentives + + align:start position:0% +um relative pay can depress incentives + + + align:start position:0% +um relative pay can depress incentives +to work + + align:start position:0% +to work + + + align:start position:0% +to work +this is the evidence by banjera the + + align:start position:0% +this is the evidence by banjera the + + + align:start position:0% +this is the evidence by banjera the +fruit pickers that i showed you + + align:start position:0% +fruit pickers that i showed you + + + align:start position:0% +fruit pickers that i showed you +pay inequality can lower performance by + + align:start position:0% +pay inequality can lower performance by + + + align:start position:0% +pay inequality can lower performance by +reduced morale so like in particular + + align:start position:0% +reduced morale so like in particular + + + align:start position:0% +reduced morale so like in particular +pay inequality is uh seemingly + + align:start position:0% +pay inequality is uh seemingly + + + align:start position:0% +pay inequality is uh seemingly +unjustified + + align:start position:0% +unjustified + + + align:start position:0% +unjustified +that's really bad for worker morale and + + align:start position:0% +that's really bad for worker morale and + + + align:start position:0% +that's really bad for worker morale and +might might lower + + align:start position:0% +might might lower + + + align:start position:0% +might might lower +our worker outputs and sort of + + align:start position:0% +our worker outputs and sort of + + + align:start position:0% +our worker outputs and sort of +attendance and so on + + align:start position:0% +attendance and so on + + + align:start position:0% +attendance and so on +third social preferences appear to be + + align:start position:0% +third social preferences appear to be + + + align:start position:0% +third social preferences appear to be +malleable + + align:start position:0% +malleable + + + align:start position:0% +malleable +and shaped by uh external factors + + align:start position:0% +and shaped by uh external factors + + + align:start position:0% +and shaped by uh external factors +in particular um there's evidence in + + align:start position:0% +in particular um there's evidence in + + + align:start position:0% +in particular um there's evidence in +favor of the + + align:start position:0% +favor of the + + + align:start position:0% +favor of the +contact hypothesis being exposed to + + align:start position:0% +contact hypothesis being exposed to + + + align:start position:0% +contact hypothesis being exposed to +others from different backgrounds really + + align:start position:0% +others from different backgrounds really + + + align:start position:0% +others from different backgrounds really +seems to uh + + align:start position:0% +seems to uh + + + align:start position:0% +seems to uh +make us more tolerant and more + + align:start position:0% +make us more tolerant and more + + + align:start position:0% +make us more tolerant and more +understanding more pro-social + + align:start position:0% +understanding more pro-social + + + align:start position:0% +understanding more pro-social +towards these other groups but also more + + align:start position:0% +towards these other groups but also more + + + align:start position:0% +towards these other groups but also more +pro-social perhaps + + align:start position:0% +pro-social perhaps + + + align:start position:0% +pro-social perhaps +in general which is the the evidence by + + align:start position:0% +in general which is the the evidence by + + + align:start position:0% +in general which is the the evidence by +gautam rao + + align:start position:0% +gautam rao + + + align:start position:0% +gautam rao +and then finally there's some evidence + + align:start position:0% +and then finally there's some evidence + + + align:start position:0% +and then finally there's some evidence +that bias beliefs may + + align:start position:0% +that bias beliefs may + + + align:start position:0% +that bias beliefs may +lower pro-sociality in a sense that like + + align:start position:0% +lower pro-sociality in a sense that like + + + align:start position:0% +lower pro-sociality in a sense that like +people might under + + align:start position:0% +people might under + + + align:start position:0% +people might under +invest potentially in how nice they are + + align:start position:0% +invest potentially in how nice they are + + + align:start position:0% +invest potentially in how nice they are +to others + + align:start position:0% +to others + + + align:start position:0% +to others +perhaps because they misunderstand what + + align:start position:0% +perhaps because they misunderstand what + + + align:start position:0% +perhaps because they misunderstand what +the effect of + + align:start position:0% +the effect of + + + align:start position:0% +the effect of +engaging in such pro-social act might + + align:start position:0% +engaging in such pro-social act might + + + align:start position:0% +engaging in such pro-social act might +have on others + + align:start position:0% +have on others + + + align:start position:0% +have on others +and so potentially correcting these + + align:start position:0% +and so potentially correcting these + + + align:start position:0% +and so potentially correcting these +beliefs or experimenting + + align:start position:0% +beliefs or experimenting + + + align:start position:0% +beliefs or experimenting +might sort of increase pro-sociality at + + align:start position:0% +might sort of increase pro-sociality at + + + align:start position:0% +might sort of increase pro-sociality at +least in some + + align:start position:0% +least in some + + + align:start position:0% +least in some +settings now um what's coming next what + + align:start position:0% +settings now um what's coming next what + + + align:start position:0% +settings now um what's coming next what +are the next lectures lecture number 14 + + align:start position:0% +are the next lectures lecture number 14 + + + align:start position:0% +are the next lectures lecture number 14 +is about + + align:start position:0% +is about + + + align:start position:0% +is about +limited attention 15 is about projection + + align:start position:0% +limited attention 15 is about projection + + + align:start position:0% +limited attention 15 is about projection +and attribution bias + + align:start position:0% +and attribution bias + + + align:start position:0% +and attribution bias +this is the idea that people have + + align:start position:0% +this is the idea that people have + + + align:start position:0% +this is the idea that people have +trouble + + align:start position:0% +trouble + + + align:start position:0% +trouble +projecting how they might feel in + + align:start position:0% +projecting how they might feel in + + + align:start position:0% +projecting how they might feel in +different states of the world + + align:start position:0% +different states of the world + + + align:start position:0% +different states of the world +that is the idea if you're really hungry + + align:start position:0% +that is the idea if you're really hungry + + + align:start position:0% +that is the idea if you're really hungry +it's really hard to project how you + + align:start position:0% +it's really hard to project how you + + + align:start position:0% +it's really hard to project how you +might feel when you're not hungry and + + align:start position:0% +might feel when you're not hungry and + + + align:start position:0% +might feel when you're not hungry and +vice versa + + align:start position:0% +vice versa + + + align:start position:0% +vice versa +we're going to look at that and lecture + + align:start position:0% +we're going to look at that and lecture + + + align:start position:0% +we're going to look at that and lecture +16 and 17 we'll look + + align:start position:0% +16 and 17 we'll look + + + align:start position:0% +16 and 17 we'll look +more specifically about beliefs and + + align:start position:0% +more specifically about beliefs and + + + align:start position:0% +more specifically about beliefs and +learning we talked a little bit about + + align:start position:0% +learning we talked a little bit about + + + align:start position:0% +learning we talked a little bit about +beliefs already in various ways + + align:start position:0% +beliefs already in various ways + + + align:start position:0% +beliefs already in various ways +but they're now we're going to talk + + align:start position:0% +but they're now we're going to talk + + + align:start position:0% +but they're now we're going to talk +specifically about like biases and + + align:start position:0% +specifically about like biases and + + + align:start position:0% +specifically about like biases and +beliefs and + + align:start position:0% +beliefs and + + + align:start position:0% +beliefs and +learning as in like people um uh uh + + align:start position:0% +learning as in like people um uh uh + + + align:start position:0% +learning as in like people um uh uh +suboptimally learning perhaps because of + + align:start position:0% +suboptimally learning perhaps because of + + + align:start position:0% +suboptimally learning perhaps because of +um computational issues in a sense + + align:start position:0% +um computational issues in a sense + + + align:start position:0% +um computational issues in a sense +that's really hard to learn in some + + align:start position:0% +that's really hard to learn in some + + + align:start position:0% +that's really hard to learn in some +settings in part because of motivated + + align:start position:0% +settings in part because of motivated + + + align:start position:0% +settings in part because of motivated +beliefs + + align:start position:0% +beliefs + + + align:start position:0% +beliefs +people might be uh drive utility from + + align:start position:0% +people might be uh drive utility from + + + align:start position:0% +people might be uh drive utility from +their beliefs + + align:start position:0% +their beliefs + + + align:start position:0% +their beliefs +as in for example i might want to think + + align:start position:0% +as in for example i might want to think + + + align:start position:0% +as in for example i might want to think +that i'm a good-looking smart + + align:start position:0% +that i'm a good-looking smart + + + align:start position:0% +that i'm a good-looking smart +and a good teacher and if + + align:start position:0% +and a good teacher and if + + + align:start position:0% +and a good teacher and if +i get feedback on one way or the other i + + align:start position:0% +i get feedback on one way or the other i + + + align:start position:0% +i get feedback on one way or the other i +might react to + + align:start position:0% +might react to + + + align:start position:0% +might react to +positive feedback a lot more i might + + align:start position:0% +positive feedback a lot more i might + + + align:start position:0% +positive feedback a lot more i might +sort of update positively if somebody + + align:start position:0% +sort of update positively if somebody + + + align:start position:0% +sort of update positively if somebody +says frank you're really smart i might + + align:start position:0% +says frank you're really smart i might + + + align:start position:0% +says frank you're really smart i might +sort of update positively + + align:start position:0% +sort of update positively + + + align:start position:0% +sort of update positively +because i feel really good about it if + + align:start position:0% +because i feel really good about it if + + + align:start position:0% +because i feel really good about it if +somebody says and said frank you're not + + align:start position:0% +somebody says and said frank you're not + + + align:start position:0% +somebody says and said frank you're not +so smart i might mostly ignore that + + align:start position:0% +so smart i might mostly ignore that + + + align:start position:0% +so smart i might mostly ignore that +feedback + + align:start position:0% +feedback + + + align:start position:0% +feedback +because um it might make me feel bad + + align:start position:0% +because um it might make me feel bad + + + align:start position:0% +because um it might make me feel bad +about + + align:start position:0% +about + + + align:start position:0% +about +myself so that's all for now thank you + + align:start position:0% +myself so that's all for now thank you + + + align:start position:0% +myself so that's all for now thank you +so much + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/KNRMz9YPCOY.txt b/KNRMz9YPCOY.txt new file mode 100644 index 0000000000000000000000000000000000000000..ff4e863d43e8fb4a6aaa7f3fa7316777cb5840dd --- /dev/null +++ b/KNRMz9YPCOY.txt @@ -0,0 +1,16184 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a creative commons license + + align:start position:0% +a creative commons license + + + align:start position:0% +a creative commons license +your support will help mit + + align:start position:0% +your support will help mit + + + align:start position:0% +your support will help mit +opencourseware continue to offer high + + align:start position:0% +opencourseware continue to offer high + + + align:start position:0% +opencourseware continue to offer high +quality educational resources for free + + align:start position:0% +quality educational resources for free + + + align:start position:0% +quality educational resources for free +to make a donation or view additional + + align:start position:0% +to make a donation or view additional + + + align:start position:0% +to make a donation or view additional +materials from hundreds of mit courses + + align:start position:0% +materials from hundreds of mit courses + + + align:start position:0% +materials from hundreds of mit courses +visit mit open courseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +okay let me say the big idea is + + align:start position:0% +okay let me say the big idea is + + + align:start position:0% +okay let me say the big idea is +for lqr trees again and you can tell me + + align:start position:0% +for lqr trees again and you can tell me + + + align:start position:0% +for lqr trees again and you can tell me +where you want more details + + align:start position:0% +where you want more details + + + align:start position:0% +where you want more details +so + + align:start position:0% + + + + align:start position:0% + +here's the basic story + + align:start position:0% +here's the basic story + + + align:start position:0% +here's the basic story +i've got some goal i want to get to + + align:start position:0% +i've got some goal i want to get to + + + align:start position:0% +i've got some goal i want to get to +and i've got a lot of potential i'd like + + align:start position:0% +and i've got a lot of potential i'd like + + + align:start position:0% +and i've got a lot of potential i'd like +to be able to get there from every + + align:start position:0% +to be able to get there from every + + + align:start position:0% +to be able to get there from every +initial condition let's say + + align:start position:0% +initial condition let's say + + + align:start position:0% +initial condition let's say +so the idea was we know how to design we + + align:start position:0% +so the idea was we know how to design we + + + align:start position:0% +so the idea was we know how to design we +know how to stabilize trajectories so + + align:start position:0% +know how to stabilize trajectories so + + + align:start position:0% +know how to stabilize trajectories so +let's just pick a point at random + + align:start position:0% +let's just pick a point at random + + + align:start position:0% +let's just pick a point at random +design a path to the goal like that + + align:start position:0% + + + + align:start position:0% + +design the + + align:start position:0% +design the + + + align:start position:0% +design the +ltv lqr stabilizer on this + + align:start position:0% +ltv lqr stabilizer on this + + + align:start position:0% +ltv lqr stabilizer on this +the great thing about that is first of + + align:start position:0% +the great thing about that is first of + + + align:start position:0% +the great thing about that is first of +all that it will locally stabilize the + + align:start position:0% +all that it will locally stabilize the + + + align:start position:0% +all that it will locally stabilize the +trajectory + + align:start position:0% +trajectory + + + align:start position:0% +trajectory +but second of all because we can compute + + align:start position:0% +but second of all because we can compute + + + align:start position:0% +but second of all because we can compute +not only because we are given + + align:start position:0% +not only because we are given + + + align:start position:0% +not only because we are given +both u equals + + align:start position:0% +both u equals + + + align:start position:0% +both u equals +some time varying + + align:start position:0% +some time varying + + + align:start position:0% +some time varying +we have a feedback policy from from that + + align:start position:0% +we have a feedback policy from from that + + + align:start position:0% +we have a feedback policy from from that +but we're also given an estimate of + + align:start position:0% +but we're also given an estimate of + + + align:start position:0% +but we're also given an estimate of +the cost to go + + align:start position:0% +the cost to go + + + align:start position:0% +the cost to go +which is + + align:start position:0% +which is + + + align:start position:0% +which is +in this + + align:start position:0% +in this + + + align:start position:0% +in this +time varying + + align:start position:0% + + + + align:start position:0% + +matrix + + align:start position:0% +matrix + + + align:start position:0% +matrix +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +the roccati equation backwards + + align:start position:0% + + + + align:start position:0% + +because of that we when we're doing our + + align:start position:0% +because of that we when we're doing our + + + align:start position:0% +because of that we when we're doing our +lqr design we actually have a good + + align:start position:0% +lqr design we actually have a good + + + align:start position:0% +lqr design we actually have a good +candidate for a lyapunov function for + + align:start position:0% +candidate for a lyapunov function for + + + align:start position:0% +candidate for a lyapunov function for +the system + + align:start position:0% +the system + + + align:start position:0% +the system +around that trajectory + + align:start position:0% +around that trajectory + + + align:start position:0% +around that trajectory +so that's a that's an important + + align:start position:0% +so that's a that's an important + + + align:start position:0% +so that's a that's an important +observation + + align:start position:0% +observation + + + align:start position:0% +observation +that when we do ltv lqr + + align:start position:0% +that when we do ltv lqr + + + align:start position:0% +that when we do ltv lqr +on a trajectory + + align:start position:0% +on a trajectory + + + align:start position:0% +on a trajectory +we get both okay + + align:start position:0% +we get both okay + + + align:start position:0% +we get both okay +now this thing + + align:start position:0% +now this thing + + + align:start position:0% +now this thing +for the linear system even the linear + + align:start position:0% +for the linear system even the linear + + + align:start position:0% +for the linear system even the linear +time varying system this is a truly + + align:start position:0% +time varying system this is a truly + + + align:start position:0% +time varying system this is a truly +openoff function from all initial states + + align:start position:0% +openoff function from all initial states + + + align:start position:0% +openoff function from all initial states +the + + align:start position:0% +the + + + align:start position:0% +the +this function will just only get smaller + + align:start position:0% +this function will just only get smaller + + + align:start position:0% +this function will just only get smaller +with time + + align:start position:0% +with time + + + align:start position:0% +with time +okay but on the action since the actual + + align:start position:0% +okay but on the action since the actual + + + align:start position:0% +okay but on the action since the actual +system is non-linear as i get farther + + align:start position:0% +system is non-linear as i get farther + + + align:start position:0% +system is non-linear as i get farther +from my trajectory + + align:start position:0% +from my trajectory + + + align:start position:0% +from my trajectory +some of the non-linearity is going to + + align:start position:0% +some of the non-linearity is going to + + + align:start position:0% +some of the non-linearity is going to +come in and corrupt + + align:start position:0% +come in and corrupt + + + align:start position:0% +come in and corrupt +my + + align:start position:0% +my + + + align:start position:0% +my +my lyapunov function + + align:start position:0% +my lyapunov function + + + align:start position:0% +my lyapunov function +at some point when i get far enough from + + align:start position:0% +at some point when i get far enough from + + + align:start position:0% +at some point when i get far enough from +the trajectory those higher order terms + + align:start position:0% +the trajectory those higher order terms + + + align:start position:0% +the trajectory those higher order terms +are going to mean that this thing + + align:start position:0% +are going to mean that this thing + + + align:start position:0% +are going to mean that this thing +doesn't have a negative + + align:start position:0% +doesn't have a negative + + + align:start position:0% +doesn't have a negative +time derivative right what i care about + + align:start position:0% +time derivative right what i care about + + + align:start position:0% +time derivative right what i care about +for the opera function + + align:start position:0% +for the opera function + + + align:start position:0% +for the opera function +is that this thing + + align:start position:0% +is that this thing + + + align:start position:0% +is that this thing +is less than or equal to zero + + align:start position:0% + + + + align:start position:0% + +so the idea with the certificates + + align:start position:0% +so the idea with the certificates + + + align:start position:0% +so the idea with the certificates +is to do a higher order polynomial + + align:start position:0% +is to do a higher order polynomial + + + align:start position:0% +is to do a higher order polynomial +expansion of the dynamics along this + + align:start position:0% +expansion of the dynamics along this + + + align:start position:0% +expansion of the dynamics along this +trajectory + + align:start position:0% +trajectory + + + align:start position:0% +trajectory +and try to estimate the threshold + + align:start position:0% +and try to estimate the threshold + + + align:start position:0% +and try to estimate the threshold +where + + align:start position:0% +where + + + align:start position:0% +where +this stops being true + + align:start position:0% +this stops being true + + + align:start position:0% +this stops being true +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and that gives me + + align:start position:0% +and that gives me + + + align:start position:0% +and that gives me +essentially + + align:start position:0% + + + + align:start position:0% + +a funnel if i do it everywhere in time + + align:start position:0% +a funnel if i do it everywhere in time + + + align:start position:0% +a funnel if i do it everywhere in time +that gives me a funnel along the + + align:start position:0% +that gives me a funnel along the + + + align:start position:0% +that gives me a funnel along the +trajectory + + align:start position:0% + + + + align:start position:0% + +over which i know the + + align:start position:0% +over which i know the + + + align:start position:0% +over which i know the +lqr + + align:start position:0% +lqr + + + align:start position:0% +lqr +cost to go + + align:start position:0% +cost to go + + + align:start position:0% +cost to go +is a liapanov function + + align:start position:0% +is a liapanov function + + + align:start position:0% +is a liapanov function +for the nonlinear system + + align:start position:0% +for the nonlinear system + + + align:start position:0% +for the nonlinear system +and it's mostly conservative the way + + align:start position:0% +and it's mostly conservative the way + + + align:start position:0% +and it's mostly conservative the way +that we can the way that we construct + + align:start position:0% +that we can the way that we construct + + + align:start position:0% +that we can the way that we construct +that threshold + + align:start position:0% +that threshold + + + align:start position:0% +that threshold +is mostly conservative + + align:start position:0% +is mostly conservative + + + align:start position:0% +is mostly conservative +the only weakness of it meaning the base + + align:start position:0% +the only weakness of it meaning the base + + + align:start position:0% +the only weakness of it meaning the base +the real base and attraction should be + + align:start position:0% +the real base and attraction should be + + + align:start position:0% +the real base and attraction should be +bigger than this estimate + + align:start position:0% +bigger than this estimate + + + align:start position:0% +bigger than this estimate +the only weakness is that i'm only doing + + align:start position:0% +the only weakness is that i'm only doing + + + align:start position:0% +the only weakness is that i'm only doing +it by doing a polynomial expansion of + + align:start position:0% +it by doing a polynomial expansion of + + + align:start position:0% +it by doing a polynomial expansion of +the system here so if there was a hard + + align:start position:0% +the system here so if there was a hard + + + align:start position:0% +the system here so if there was a hard +discontinuity right next to the + + align:start position:0% +discontinuity right next to the + + + align:start position:0% +discontinuity right next to the +trajectory that didn't show up in the + + align:start position:0% +trajectory that didn't show up in the + + + align:start position:0% +trajectory that didn't show up in the +taylor expansion then i wouldn't ever + + align:start position:0% +taylor expansion then i wouldn't ever + + + align:start position:0% +taylor expansion then i wouldn't ever +see it i'm not exhaustively searching + + align:start position:0% +see it i'm not exhaustively searching + + + align:start position:0% +see it i'm not exhaustively searching +this the non-linearity around that + + align:start position:0% +this the non-linearity around that + + + align:start position:0% +this the non-linearity around that +trajectory + + align:start position:0% +trajectory + + + align:start position:0% +trajectory +i'm just saying along this trajectory + + align:start position:0% +i'm just saying along this trajectory + + + align:start position:0% +i'm just saying along this trajectory +what are the higher order expansion i do + + align:start position:0% +what are the higher order expansion i do + + + align:start position:0% +what are the higher order expansion i do +a taylor expansion of a third order + + align:start position:0% +a taylor expansion of a third order + + + align:start position:0% +a taylor expansion of a third order +fourth order whatever it takes + + align:start position:0% +fourth order whatever it takes + + + align:start position:0% +fourth order whatever it takes +and i use that to check when it breaks + + align:start position:0% +and i use that to check when it breaks + + + align:start position:0% +and i use that to check when it breaks +the + + align:start position:0% +the + + + align:start position:0% +the +the + + align:start position:0% +the + + + align:start position:0% +the +cost to go okay + + align:start position:0% + + + + align:start position:0% + +so that's the certificate that's just if + + align:start position:0% +so that's the certificate that's just if + + + align:start position:0% +so that's the certificate that's just if +i have a single trajectory then i can + + align:start position:0% +i have a single trajectory then i can + + + align:start position:0% +i have a single trajectory then i can +use this the real cool thing is that + + align:start position:0% +use this the real cool thing is that + + + align:start position:0% +use this the real cool thing is that +thanks to pablo and and sasha mcgretzky + + align:start position:0% +thanks to pablo and and sasha mcgretzky + + + align:start position:0% +thanks to pablo and and sasha mcgretzky +we can do that efficiently with a convex + + align:start position:0% +we can do that efficiently with a convex + + + align:start position:0% +we can do that efficiently with a convex +optimization + + align:start position:0% +optimization + + + align:start position:0% +optimization +and then the idea is if i can do it for + + align:start position:0% +and then the idea is if i can do it for + + + align:start position:0% +and then the idea is if i can do it for +a single trajectory + + align:start position:0% +a single trajectory + + + align:start position:0% +a single trajectory +then why not put that back into a sort + + align:start position:0% +then why not put that back into a sort + + + align:start position:0% +then why not put that back into a sort +of an rrt kind of framework + + align:start position:0% +of an rrt kind of framework + + + align:start position:0% +of an rrt kind of framework +and try to build lots of trajectories + + align:start position:0% +and try to build lots of trajectories + + + align:start position:0% +and try to build lots of trajectories +that are stabilized + + align:start position:0% +that are stabilized + + + align:start position:0% +that are stabilized +okay so the first step was just to pick + + align:start position:0% +okay so the first step was just to pick + + + align:start position:0% +okay so the first step was just to pick +a point in random design a single + + align:start position:0% +a point in random design a single + + + align:start position:0% +a point in random design a single +trajectory + + align:start position:0% +trajectory + + + align:start position:0% +trajectory +the second step is let's pick a new + + align:start position:0% +the second step is let's pick a new + + + align:start position:0% +the second step is let's pick a new +random point + + align:start position:0% +random point + + + align:start position:0% +random point +i don't actually have to go all the way + + align:start position:0% +i don't actually have to go all the way + + + align:start position:0% +i don't actually have to go all the way +back to my goal i just have to go to the + + align:start position:0% +back to my goal i just have to go to the + + + align:start position:0% +back to my goal i just have to go to the +nearest point on the current tree + + align:start position:0% +nearest point on the current tree + + + align:start position:0% +nearest point on the current tree +and stabilize that + + align:start position:0% +and stabilize that + + + align:start position:0% +and stabilize that +right + + align:start position:0% +right + + + align:start position:0% +right +and then i pick another point + + align:start position:0% +and then i pick another point + + + align:start position:0% +and then i pick another point +find the nearest point on the closer + + align:start position:0% +find the nearest point on the closer + + + align:start position:0% +find the nearest point on the closer +close on the tree + + align:start position:0% +close on the tree + + + align:start position:0% +close on the tree +build the trajectory and like that + + align:start position:0% +build the trajectory and like that + + + align:start position:0% +build the trajectory and like that +stabilize that + + align:start position:0% +stabilize that + + + align:start position:0% +stabilize that +right if i pick a new point and it's + + align:start position:0% +right if i pick a new point and it's + + + align:start position:0% +right if i pick a new point and it's +already in the basin of attraction i + + align:start position:0% +already in the basin of attraction i + + + align:start position:0% +already in the basin of attraction i +don't i don't need to add + + align:start position:0% +don't i don't need to add + + + align:start position:0% +don't i don't need to add +an edge that was that would be sort of a + + align:start position:0% +an edge that was that would be sort of a + + + align:start position:0% +an edge that was that would be sort of a +waste of my time + + align:start position:0% +waste of my time + + + align:start position:0% +waste of my time +so + + align:start position:0% +so + + + align:start position:0% +so +the effect is i get these + + align:start position:0% +the effect is i get these + + + align:start position:0% +the effect is i get these +um i didn't say carefully what the + + align:start position:0% +um i didn't say carefully what the + + + align:start position:0% +um i didn't say carefully what the +results are because i can't prove them + + align:start position:0% +results are because i can't prove them + + + align:start position:0% +results are because i can't prove them +yet this is still hot off the press but + + align:start position:0% +yet this is still hot off the press but + + + align:start position:0% +yet this is still hot off the press but +i think + + align:start position:0% +i think + + + align:start position:0% +i think +that + + align:start position:0% +that + + + align:start position:0% +that +i can say that it probabilistically + + align:start position:0% +i can say that it probabilistically + + + align:start position:0% +i can say that it probabilistically +covers the reachable state space + + align:start position:0% +covers the reachable state space + + + align:start position:0% +covers the reachable state space +every place that i can get to the goal + + align:start position:0% +every place that i can get to the goal + + + align:start position:0% +every place that i can get to the goal +from + + align:start position:0% +from + + + align:start position:0% +from +there exists controller + + align:start position:0% +there exists controller + + + align:start position:0% +there exists controller +if i design enough samples i should be + + align:start position:0% +if i design enough samples i should be + + + align:start position:0% +if i design enough samples i should be +able to get to the goal + + align:start position:0% +able to get to the goal + + + align:start position:0% +able to get to the goal +given i do enough steps of my lqr tree + + align:start position:0% +given i do enough steps of my lqr tree + + + align:start position:0% +given i do enough steps of my lqr tree +so as time goes to infinity the entire + + align:start position:0% +so as time goes to infinity the entire + + + align:start position:0% +so as time goes to infinity the entire +space will be covered + + align:start position:0% +space will be covered + + + align:start position:0% +space will be covered +with basin of attraction of a controller + + align:start position:0% +with basin of attraction of a controller + + + align:start position:0% +with basin of attraction of a controller +that gets me to the goal which is a + + align:start position:0% +that gets me to the goal which is a + + + align:start position:0% +that gets me to the goal which is a +pretty powerful thing to say if you're + + align:start position:0% +pretty powerful thing to say if you're + + + align:start position:0% +pretty powerful thing to say if you're +willing to wait till time goes to + + align:start position:0% +willing to wait till time goes to + + + align:start position:0% +willing to wait till time goes to +infinity + + align:start position:0% +infinity + + + align:start position:0% +infinity +and the + + align:start position:0% +and the + + + align:start position:0% +and the +practical thing that's nice about it is + + align:start position:0% +practical thing that's nice about it is + + + align:start position:0% +practical thing that's nice about it is +it seems to happen pretty quick with a + + align:start position:0% +it seems to happen pretty quick with a + + + align:start position:0% +it seems to happen pretty quick with a +handful with a fairly small number of + + align:start position:0% +handful with a fairly small number of + + + align:start position:0% +handful with a fairly small number of +trajectories + + align:start position:0% +trajectories + + + align:start position:0% +trajectories +yeah chuck you want to keep the knob in + + align:start position:0% +yeah chuck you want to keep the knob in + + + align:start position:0% +yeah chuck you want to keep the knob in +your system as that includes property + + align:start position:0% +your system as that includes property + + + align:start position:0% +your system as that includes property +would you have to let it sample inside + + align:start position:0% +would you have to let it sample inside + + + align:start position:0% +would you have to let it sample inside +the basics of attraction + + align:start position:0% +the basics of attraction + + + align:start position:0% +the basics of attraction +yeah so that's that's why i have to + + align:start position:0% +yeah so that's that's why i have to + + + align:start position:0% +yeah so that's that's why i have to +qualify the guarantees i'm only saying + + align:start position:0% +qualify the guarantees i'm only saying + + + align:start position:0% +qualify the guarantees i'm only saying +the non-linear system as represented as + + align:start position:0% +the non-linear system as represented as + + + align:start position:0% +the non-linear system as represented as +the taylor expansion around the + + align:start position:0% +the taylor expansion around the + + + align:start position:0% +the taylor expansion around the +trajectories that's the that's the + + align:start position:0% +trajectories that's the that's the + + + align:start position:0% +trajectories that's the that's the +weakness so it really only works for + + align:start position:0% +weakness so it really only works for + + + align:start position:0% +weakness so it really only works for +smooth systems if there's a cliff + + align:start position:0% +smooth systems if there's a cliff + + + align:start position:0% +smooth systems if there's a cliff +here and i'm designing a trajectory + + align:start position:0% +here and i'm designing a trajectory + + + align:start position:0% +here and i'm designing a trajectory +right here it might come up with a + + align:start position:0% +right here it might come up with a + + + align:start position:0% +right here it might come up with a +saying a basin of attractions here even + + align:start position:0% +saying a basin of attractions here even + + + align:start position:0% +saying a basin of attractions here even +though that's just not true + + align:start position:0% +though that's just not true + + + align:start position:0% +though that's just not true +okay if i smooth the cliff sorry john if + + align:start position:0% +okay if i smooth the cliff sorry john if + + + align:start position:0% +okay if i smooth the cliff sorry john if +i smooth the cliff + + align:start position:0% +i smooth the cliff + + + align:start position:0% +i smooth the cliff +um + + align:start position:0% +um + + + align:start position:0% +um +and therefore + + align:start position:0% +and therefore + + + align:start position:0% +and therefore +when i tailor expand here i can see that + + align:start position:0% +when i tailor expand here i can see that + + + align:start position:0% +when i tailor expand here i can see that +there's a cliff there then i'd like to + + align:start position:0% +there's a cliff there then i'd like to + + + align:start position:0% +there's a cliff there then i'd like to +think that the + + align:start position:0% +think that the + + + align:start position:0% +think that the +um that the uh certificates would would + + align:start position:0% +um that the uh certificates would would + + + align:start position:0% +um that the uh certificates would would +do the right thing but if it's a + + align:start position:0% +do the right thing but if it's a + + + align:start position:0% +do the right thing but if it's a +hardcliff that where the where the + + align:start position:0% +hardcliff that where the where the + + + align:start position:0% +hardcliff that where the where the +higher order expansion here doesn't see + + align:start position:0% +higher order expansion here doesn't see + + + align:start position:0% +higher order expansion here doesn't see +that cliff then there's no hope + + align:start position:0% + + + + align:start position:0% + +that's a good question so just building + + align:start position:0% +that's a good question so just building + + + align:start position:0% +that's a good question so just building +more and more accurate certificates as + + align:start position:0% +more and more accurate certificates as + + + align:start position:0% +more and more accurate certificates as +time goes to infinity it could be + + align:start position:0% +time goes to infinity it could be + + + align:start position:0% +time goes to infinity it could be +it could be that it could be a good idea + + align:start position:0% +it could be that it could be a good idea + + + align:start position:0% +it could be that it could be a good idea +um my suspicion is that + + align:start position:0% +um my suspicion is that + + + align:start position:0% +um my suspicion is that +in practice this is going to be good + + align:start position:0% +in practice this is going to be good + + + align:start position:0% +in practice this is going to be good +enough for and and we're not going to + + align:start position:0% +enough for and and we're not going to + + + align:start position:0% +enough for and and we're not going to +want to do the + + align:start position:0% +want to do the + + + align:start position:0% +want to do the +maybe i'm just + + align:start position:0% +maybe i'm just + + + align:start position:0% +maybe i'm just +the kind of guy that cuts a corner cuts + + align:start position:0% +the kind of guy that cuts a corner cuts + + + align:start position:0% +the kind of guy that cuts a corner cuts +the corners but i think this is a pretty + + align:start position:0% +the corners but i think this is a pretty + + + align:start position:0% +the corners but i think this is a pretty +good + + align:start position:0% +good + + + align:start position:0% +good +solution + + align:start position:0% + + + + align:start position:0% + +so i use i whenever i design each + + align:start position:0% +so i use i whenever i design each + + + align:start position:0% +so i use i whenever i design each +trajectory i use der call why not + + align:start position:0% +trajectory i use der call why not + + + align:start position:0% +trajectory i use der call why not +but it's so so i can sort of say they're + + align:start position:0% +but it's so so i can sort of say they're + + + align:start position:0% +but it's so so i can sort of say they're +locally optimal in the branches that + + align:start position:0% +locally optimal in the branches that + + + align:start position:0% +locally optimal in the branches that +they are + + align:start position:0% +they are + + + align:start position:0% +they are +just because that's easy to easy to + + align:start position:0% +just because that's easy to easy to + + + align:start position:0% +just because that's easy to easy to +accomplish but there's no sense in which + + align:start position:0% +accomplish but there's no sense in which + + + align:start position:0% +accomplish but there's no sense in which +it's globally optimal + + align:start position:0% +it's globally optimal + + + align:start position:0% +it's globally optimal +right so i just i just try to say that + + align:start position:0% +right so i just i just try to say that + + + align:start position:0% +right so i just i just try to say that +every state will eventually get there + + align:start position:0% +every state will eventually get there + + + align:start position:0% +every state will eventually get there +not that it'll get there optimally + + align:start position:0% + + + + align:start position:0% + +but again if you're allowed to sample + + align:start position:0% +but again if you're allowed to sample + + + align:start position:0% +but again if you're allowed to sample +inside + + align:start position:0% +inside + + + align:start position:0% +inside +the basis of attraction you would + + align:start position:0% +the basis of attraction you would + + + align:start position:0% +the basis of attraction you would +probably + + align:start position:0% +probably + + + align:start position:0% +probably +get some kind of convergence to global + + align:start position:0% +get some kind of convergence to global + + + align:start position:0% +get some kind of convergence to global +optimal + + align:start position:0% +optimal + + + align:start position:0% +optimal +um + + align:start position:0% + + + + align:start position:0% + +there are there are ways to try to get + + align:start position:0% +there are there are ways to try to get + + + align:start position:0% +there are there are ways to try to get +at that problem i don't think it's a one + + align:start position:0% +at that problem i don't think it's a one + + + align:start position:0% +at that problem i don't think it's a one +step change from what i said i think you + + align:start position:0% +step change from what i said i think you + + + align:start position:0% +step change from what i said i think you +have to do something more + + align:start position:0% +have to do something more + + + align:start position:0% +have to do something more +i mean any one of these trajectories + + align:start position:0% +i mean any one of these trajectories + + + align:start position:0% +i mean any one of these trajectories +right um + + align:start position:0% +right um + + + align:start position:0% +right um +maybe that's getting busy any one of + + align:start position:0% +maybe that's getting busy any one of + + + align:start position:0% +maybe that's getting busy any one of +those trajectories is just locally + + align:start position:0% +those trajectories is just locally + + + align:start position:0% +those trajectories is just locally +optimal right so let's consider the case + + align:start position:0% +optimal right so let's consider the case + + + align:start position:0% +optimal right so let's consider the case +where + + align:start position:0% +where + + + align:start position:0% +where +the goal is here there's a + + align:start position:0% +the goal is here there's a + + + align:start position:0% +the goal is here there's a +something here and i i did this and for + + align:start position:0% +something here and i i did this and for + + + align:start position:0% +something here and i i did this and for +some reason i got a + + align:start position:0% +some reason i got a + + + align:start position:0% +some reason i got a +trajectory like that + + align:start position:0% + + + + align:start position:0% + +which is locally optimal but not + + align:start position:0% +which is locally optimal but not + + + align:start position:0% +which is locally optimal but not +globally optimal because there's a + + align:start position:0% +globally optimal because there's a + + + align:start position:0% +globally optimal because there's a +shorter path here so i need to somehow i + + align:start position:0% +shorter path here so i need to somehow i + + + align:start position:0% +shorter path here so i need to somehow i +would need to somehow include the + + align:start position:0% +would need to somehow include the + + + align:start position:0% +would need to somehow include the +mechanism which is i think what you're + + align:start position:0% +mechanism which is i think what you're + + + align:start position:0% +mechanism which is i think what you're +getting at to + + align:start position:0% +getting at to + + + align:start position:0% +getting at to +eventually take a dip + + align:start position:0% +eventually take a dip + + + align:start position:0% +eventually take a dip +find a different path to the same place + + align:start position:0% +find a different path to the same place + + + align:start position:0% +find a different path to the same place +and overwrite the old path and i don't + + align:start position:0% +and overwrite the old path and i don't + + + align:start position:0% +and overwrite the old path and i don't +have any + + align:start position:0% +have any + + + align:start position:0% +have any +mechanism for that inside and it turns + + align:start position:0% +mechanism for that inside and it turns + + + align:start position:0% +mechanism for that inside and it turns +out that's actually what i was going for + + align:start position:0% +out that's actually what i was going for + + + align:start position:0% +out that's actually what i was going for +initially turns out to be a little bit + + align:start position:0% +initially turns out to be a little bit + + + align:start position:0% +initially turns out to be a little bit +non-trivial to to do + + align:start position:0% +non-trivial to to do + + + align:start position:0% +non-trivial to to do +chris atkinson has a nice idea + + align:start position:0% +chris atkinson has a nice idea + + + align:start position:0% +chris atkinson has a nice idea +that that goes goes towards doing that a + + align:start position:0% +that that goes goes towards doing that a + + + align:start position:0% +that that goes goes towards doing that a +little bit more on composing trajectory + + align:start position:0% +little bit more on composing trajectory + + + align:start position:0% +little bit more on composing trajectory +libraries + + align:start position:0% +libraries + + + align:start position:0% +libraries +um but i i gave up optimality and tried + + align:start position:0% +um but i i gave up optimality and tried + + + align:start position:0% +um but i i gave up optimality and tried +to get coverage of with the basin of + + align:start position:0% +to get coverage of with the basin of + + + align:start position:0% +to get coverage of with the basin of +attraction + + align:start position:0% +attraction + + + align:start position:0% +attraction +in that design + + align:start position:0% + + + + align:start position:0% + +so so some of you been talking about to + + align:start position:0% +so so some of you been talking about to + + + align:start position:0% +so so some of you been talking about to +me about the projects and i've and + + align:start position:0% +me about the projects and i've and + + + align:start position:0% +me about the projects and i've and +have been asking about these things so + + align:start position:0% +have been asking about these things so + + + align:start position:0% +have been asking about these things so +so i think mark and matt are thinking + + align:start position:0% +so i think mark and matt are thinking + + + align:start position:0% +so i think mark and matt are thinking +about trying to to help with this i mean + + align:start position:0% +about trying to to help with this i mean + + + align:start position:0% +about trying to to help with this i mean +this is this is new i mean you guys can + + align:start position:0% +this is this is new i mean you guys can + + + align:start position:0% +this is this is new i mean you guys can +sort of + + align:start position:0% +sort of + + + align:start position:0% +sort of +definitely help with the the the idea so + + align:start position:0% +definitely help with the the the idea so + + + align:start position:0% +definitely help with the the the idea so +so i we're trying to figure out for + + align:start position:0% +so i we're trying to figure out for + + + align:start position:0% +so i we're trying to figure out for +instance if there's um actuator limits + + align:start position:0% +instance if there's um actuator limits + + + align:start position:0% +instance if there's um actuator limits +um these guys are talking about trying + + align:start position:0% +um these guys are talking about trying + + + align:start position:0% +um these guys are talking about trying +to figure out how to compute the + + align:start position:0% +to figure out how to compute the + + + align:start position:0% +to figure out how to compute the +certificates and even the lqr stabilizer + + align:start position:0% +certificates and even the lqr stabilizer + + + align:start position:0% +certificates and even the lqr stabilizer +if you if you not only have a quadratic + + align:start position:0% +if you if you not only have a quadratic + + + align:start position:0% +if you if you not only have a quadratic +cost on you but have some hard limits on + + align:start position:0% +cost on you but have some hard limits on + + + align:start position:0% +cost on you but have some hard limits on +you because that's a problem we actually + + align:start position:0% +you because that's a problem we actually + + + align:start position:0% +you because that's a problem we actually +hit in in practice so so one of the + + align:start position:0% +hit in in practice so so one of the + + + align:start position:0% +hit in in practice so so one of the +final projects in the class i think is + + align:start position:0% +final projects in the class i think is + + + align:start position:0% +final projects in the class i think is +going to be helping with that there's + + align:start position:0% +going to be helping with that there's + + + align:start position:0% +going to be helping with that there's +there's + + align:start position:0% +there's + + + align:start position:0% +there's +problems of how do you design the + + align:start position:0% +problems of how do you design the + + + align:start position:0% +problems of how do you design the +stabilizer through impacts and in + + align:start position:0% +stabilizer through impacts and in + + + align:start position:0% +stabilizer through impacts and in +periodic systems there's lots of good + + align:start position:0% +periodic systems there's lots of good + + + align:start position:0% +periodic systems there's lots of good +questions so if you're if you're excited + + align:start position:0% +questions so if you're if you're excited + + + align:start position:0% +questions so if you're if you're excited +about that idea i'm definitely excited + + align:start position:0% +about that idea i'm definitely excited + + + align:start position:0% +about that idea i'm definitely excited +about the idea right now + + align:start position:0% +about the idea right now + + + align:start position:0% +about the idea right now +then + + align:start position:0% +then + + + align:start position:0% +then +i'll see what you wrote up today but we + + align:start position:0% +i'll see what you wrote up today but we + + + align:start position:0% +i'll see what you wrote up today but we +could maybe try to find a way to connect + + align:start position:0% +could maybe try to find a way to connect + + + align:start position:0% +could maybe try to find a way to connect +that i'd be i'd be thrilled to + + align:start position:0% +that i'd be i'd be thrilled to + + + align:start position:0% +that i'd be i'd be thrilled to +to have your help in making that idea + + align:start position:0% +to have your help in making that idea + + + align:start position:0% +to have your help in making that idea +more + + align:start position:0% +more + + + align:start position:0% +more +relevant + + align:start position:0% +relevant + + + align:start position:0% +relevant +yeah + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +is that sort of cover + + align:start position:0% + + + + align:start position:0% + +now for something completely different + + align:start position:0% +now for something completely different + + + align:start position:0% +now for something completely different +although related of course + + align:start position:0% +although related of course + + + align:start position:0% +although related of course +um + + align:start position:0% +um + + + align:start position:0% +um +so in the lqr trees that basically in + + align:start position:0% +so in the lqr trees that basically in + + + align:start position:0% +so in the lqr trees that basically in +everything that we've done so far in + + align:start position:0% +everything that we've done so far in + + + align:start position:0% +everything that we've done so far in +class + + align:start position:0% +class + + + align:start position:0% +class +we've made a handful of + + align:start position:0% +we've made a handful of + + + align:start position:0% +we've made a handful of +of important + + align:start position:0% +of important + + + align:start position:0% +of important +assumptions right + + align:start position:0% + + + + align:start position:0% + +the most important one probably is + + align:start position:0% +the most important one probably is + + + align:start position:0% +the most important one probably is +they've always assumed that we have the + + align:start position:0% +they've always assumed that we have the + + + align:start position:0% +they've always assumed that we have the +model of the system right + + align:start position:0% + + + + align:start position:0% + +so next week we're going to get it how + + align:start position:0% +so next week we're going to get it how + + + align:start position:0% +so next week we're going to get it how +do you how do you do some of these + + align:start position:0% +do you how do you do some of these + + + align:start position:0% +do you how do you do some of these +optimizations when you don't even have a + + align:start position:0% +optimizations when you don't even have a + + + align:start position:0% +optimizations when you don't even have a +model okay + + align:start position:0% + + + + align:start position:0% + +we've also assumed so far that the + + align:start position:0% +we've also assumed so far that the + + + align:start position:0% +we've also assumed so far that the +um + + align:start position:0% +um + + + align:start position:0% +um +the current state of the system is known + + align:start position:0% + + + + align:start position:0% + +in other words the state of the robot is + + align:start position:0% +in other words the state of the robot is + + + align:start position:0% +in other words the state of the robot is +fully observable + + align:start position:0% + + + + align:start position:0% + +if i stop assuming that we gotta start + + align:start position:0% +if i stop assuming that we gotta start + + + align:start position:0% +if i stop assuming that we gotta start +getting into discussions about state + + align:start position:0% +getting into discussions about state + + + align:start position:0% +getting into discussions about state +estimation and we will towards the end + + align:start position:0% +estimation and we will towards the end + + + align:start position:0% +estimation and we will towards the end +of the class + + align:start position:0% +of the class + + + align:start position:0% +of the class +and there's another + + align:start position:0% +and there's another + + + align:start position:0% +and there's another +assumption we've been making which is + + align:start position:0% +assumption we've been making which is + + + align:start position:0% +assumption we've been making which is +that + + align:start position:0% + + + + align:start position:0% + +the dynamics + + align:start position:0% +the dynamics + + + align:start position:0% +the dynamics +are deterministic + + align:start position:0% +are deterministic + + + align:start position:0% +are deterministic +let's say + + align:start position:0% + + + + align:start position:0% + +right that that + + align:start position:0% +right that that + + + align:start position:0% +right that that +um + + align:start position:0% +um + + + align:start position:0% +um +pretty much the system goes right + + align:start position:0% +pretty much the system goes right + + + align:start position:0% +pretty much the system goes right +where i think it's gonna go + + align:start position:0% + + + + align:start position:0% + +no i chose to write that + + align:start position:0% +no i chose to write that + + + align:start position:0% +no i chose to write that +and then cross it out because that's not + + align:start position:0% +and then cross it out because that's not + + + align:start position:0% +and then cross it out because that's not +quite what we're assuming okay + + align:start position:0% +quite what we're assuming okay + + + align:start position:0% +quite what we're assuming okay +i wanted to i want to write that but but + + align:start position:0% +i wanted to i want to write that but but + + + align:start position:0% +i wanted to i want to write that but but +what are maybe what's a if we really + + align:start position:0% +what are maybe what's a if we really + + + align:start position:0% +what are maybe what's a if we really +were assuming that the dynamics were + + align:start position:0% +were assuming that the dynamics were + + + align:start position:0% +were assuming that the dynamics were +deterministic then we wouldn't have been + + align:start position:0% +deterministic then we wouldn't have been + + + align:start position:0% +deterministic then we wouldn't have been +spending much time talking about + + align:start position:0% +spending much time talking about + + + align:start position:0% +spending much time talking about +feedback at all + + align:start position:0% +feedback at all + + + align:start position:0% +feedback at all +we would have been just focused on + + align:start position:0% +we would have been just focused on + + + align:start position:0% +we would have been just focused on +open loop things right + + align:start position:0% +open loop things right + + + align:start position:0% +open loop things right +so let's think let's have a short + + align:start position:0% +so let's think let's have a short + + + align:start position:0% +so let's think let's have a short +philosophical argument about what we're + + align:start position:0% +philosophical argument about what we're + + + align:start position:0% +philosophical argument about what we're +actually doing here so we're not quite + + align:start position:0% +actually doing here so we're not quite + + + align:start position:0% +actually doing here so we're not quite +assuming that it's deterministic + + align:start position:0% +assuming that it's deterministic + + + align:start position:0% +assuming that it's deterministic +right maybe + + align:start position:0% +right maybe + + + align:start position:0% +right maybe +a better way to describe what we're + + align:start position:0% +a better way to describe what we're + + + align:start position:0% +a better way to describe what we're +doing is we're assuming + + align:start position:0% +doing is we're assuming + + + align:start position:0% +doing is we're assuming +something specific about the + + align:start position:0% +something specific about the + + + align:start position:0% +something specific about the +disturbances in the system + + align:start position:0% +disturbances in the system + + + align:start position:0% +disturbances in the system +we're really we're assuming that + + align:start position:0% + + + + align:start position:0% + +disturbances + + align:start position:0% + + + + align:start position:0% + +look like a change in initial conditions + + align:start position:0% +look like a change in initial conditions + + + align:start position:0% +look like a change in initial conditions +that's one way to say it right + + align:start position:0% + + + + align:start position:0% + +an unmodeled change in initial + + align:start position:0% +an unmodeled change in initial + + + align:start position:0% +an unmodeled change in initial +conditions + + align:start position:0% + + + + align:start position:0% + +right i + + align:start position:0% +right i + + + align:start position:0% +right i +by virtue of talking about these + + align:start position:0% +by virtue of talking about these + + + align:start position:0% +by virtue of talking about these +feedback stabilizers right + + align:start position:0% +feedback stabilizers right + + + align:start position:0% +feedback stabilizers right +the motivation is that okay i'm + + align:start position:0% +the motivation is that okay i'm + + + align:start position:0% +the motivation is that okay i'm +following this trajectory when the + + align:start position:0% +following this trajectory when the + + + align:start position:0% +following this trajectory when the +model's right are all is good if + + align:start position:0% +model's right are all is good if + + + align:start position:0% +model's right are all is good if +something does happen then okay it's + + align:start position:0% +something does happen then okay it's + + + align:start position:0% +something does happen then okay it's +going to move me somewhere in state + + align:start position:0% +going to move me somewhere in state + + + align:start position:0% +going to move me somewhere in state +space but as long as that's in the basin + + align:start position:0% +space but as long as that's in the basin + + + align:start position:0% +space but as long as that's in the basin +of attraction the whole idea of really a + + align:start position:0% +of attraction the whole idea of really a + + + align:start position:0% +of attraction the whole idea of really a +basis of attraction is going at the idea + + align:start position:0% +basis of attraction is going at the idea + + + align:start position:0% +basis of attraction is going at the idea +that i can handle disturbances by just + + align:start position:0% +that i can handle disturbances by just + + + align:start position:0% +that i can handle disturbances by just +being robust in state + + align:start position:0% +being robust in state + + + align:start position:0% +being robust in state +right + + align:start position:0% +right + + + align:start position:0% +right +but that's actually sort of a subtle + + align:start position:0% +but that's actually sort of a subtle + + + align:start position:0% +but that's actually sort of a subtle +thing to assume right i want to be a + + align:start position:0% +thing to assume right i want to be a + + + align:start position:0% +thing to assume right i want to be a +little bit more explicit about what that + + align:start position:0% +little bit more explicit about what that + + + align:start position:0% +little bit more explicit about what that +means + + align:start position:0% + + + + align:start position:0% + +really it sort of implies that we're + + align:start position:0% +really it sort of implies that we're + + + align:start position:0% +really it sort of implies that we're +assuming that + + align:start position:0% +assuming that + + + align:start position:0% +assuming that +disturbances are + + align:start position:0% +disturbances are + + + align:start position:0% +disturbances are +impulsive + + align:start position:0% +impulsive + + + align:start position:0% +impulsive +not constant + + align:start position:0% + + + + align:start position:0% + +instantaneous right impulsive + + align:start position:0% +instantaneous right impulsive + + + align:start position:0% +instantaneous right impulsive +if a disturbance was for my walking + + align:start position:0% +if a disturbance was for my walking + + + align:start position:0% +if a disturbance was for my walking +robot was + + align:start position:0% +robot was + + + align:start position:0% +robot was +um someone put a new weight on my leg + + align:start position:0% +um someone put a new weight on my leg + + + align:start position:0% +um someone put a new weight on my leg +then that's not + + align:start position:0% +then that's not + + + align:start position:0% +then that's not +something that our designs so far have + + align:start position:0% +something that our designs so far have + + + align:start position:0% +something that our designs so far have +handled because that's more like the + + align:start position:0% +handled because that's more like the + + + align:start position:0% +handled because that's more like the +model changed right we're talking about + + align:start position:0% +model changed right we're talking about + + + align:start position:0% +model changed right we're talking about +something that it moved me + + align:start position:0% +something that it moved me + + + align:start position:0% +something that it moved me +and now i have to deal with it right so + + align:start position:0% +and now i have to deal with it right so + + + align:start position:0% +and now i have to deal with it right so +if the disturbance lasts for a long time + + align:start position:0% +if the disturbance lasts for a long time + + + align:start position:0% +if the disturbance lasts for a long time +then that actually feels a lot more like + + align:start position:0% +then that actually feels a lot more like + + + align:start position:0% +then that actually feels a lot more like +a model change right but if it's + + align:start position:0% +a model change right but if it's + + + align:start position:0% +a model change right but if it's +impulsive i can sort of think of it as a + + align:start position:0% +impulsive i can sort of think of it as a + + + align:start position:0% +impulsive i can sort of think of it as a +change in initial condition + + align:start position:0% +change in initial condition + + + align:start position:0% +change in initial condition +and the other thing that that sort of + + align:start position:0% +and the other thing that that sort of + + + align:start position:0% +and the other thing that that sort of +implicitly assumes is that the + + align:start position:0% +implicitly assumes is that the + + + align:start position:0% +implicitly assumes is that the +disturbances are rare + + align:start position:0% + + + + align:start position:0% + +right if i got impulsive disturbances + + align:start position:0% +right if i got impulsive disturbances + + + align:start position:0% +right if i got impulsive disturbances +a thousand times a second + + align:start position:0% +a thousand times a second + + + align:start position:0% +a thousand times a second +then again + + align:start position:0% +then again + + + align:start position:0% +then again +my completely deterministic + + align:start position:0% +my completely deterministic + + + align:start position:0% +my completely deterministic +analysis isn't probably the relevant + + align:start position:0% +analysis isn't probably the relevant + + + align:start position:0% +analysis isn't probably the relevant +one okay so that's those are sort of + + align:start position:0% +one okay so that's those are sort of + + + align:start position:0% +one okay so that's those are sort of +implicitly making these assumptions the + + align:start position:0% +implicitly making these assumptions the + + + align:start position:0% +implicitly making these assumptions the +whole thing the whole idea of talking + + align:start position:0% +whole thing the whole idea of talking + + + align:start position:0% +whole thing the whole idea of talking +about basis of attraction to + + align:start position:0% +about basis of attraction to + + + align:start position:0% +about basis of attraction to +deterministic systems and doing feedback + + align:start position:0% +deterministic systems and doing feedback + + + align:start position:0% +deterministic systems and doing feedback +design sort of implicitly makes that + + align:start position:0% +design sort of implicitly makes that + + + align:start position:0% +design sort of implicitly makes that +assumption right so so there's sort of + + align:start position:0% +assumption right so so there's sort of + + + align:start position:0% +assumption right so so there's sort of +three things there + + align:start position:0% +three things there + + + align:start position:0% +three things there +right the fact that it's unmodeled + + align:start position:0% +right the fact that it's unmodeled + + + align:start position:0% +right the fact that it's unmodeled +and impulsive and rare i guess + + align:start position:0% + + + + align:start position:0% + +if your disturbances + + align:start position:0% +if your disturbances + + + align:start position:0% +if your disturbances +are not + + align:start position:0% +are not + + + align:start position:0% +are not +instantaneous rare disturbances + + align:start position:0% +instantaneous rare disturbances + + + align:start position:0% +instantaneous rare disturbances +then i think i would advocate quickly + + align:start position:0% +then i think i would advocate quickly + + + align:start position:0% +then i think i would advocate quickly +for starting to think about + + align:start position:0% +for starting to think about + + + align:start position:0% +for starting to think about +your dynamics as not deterministic + + align:start position:0% +your dynamics as not deterministic + + + align:start position:0% +your dynamics as not deterministic +dynamics but as a stochastic dynamics + + align:start position:0% +dynamics but as a stochastic dynamics + + + align:start position:0% +dynamics but as a stochastic dynamics +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and even if they are impulsive and rare + + align:start position:0% +and even if they are impulsive and rare + + + align:start position:0% +and even if they are impulsive and rare +but if you have a model of them + + align:start position:0% +but if you have a model of them + + + align:start position:0% +but if you have a model of them +then you should be still be able to do + + align:start position:0% +then you should be still be able to do + + + align:start position:0% +then you should be still be able to do +better by explicitly letting your + + align:start position:0% +better by explicitly letting your + + + align:start position:0% +better by explicitly letting your +feedback design + + align:start position:0% +feedback design + + + align:start position:0% +feedback design +reason about + + align:start position:0% +reason about + + + align:start position:0% +reason about +the stochastic dynamics + + align:start position:0% +the stochastic dynamics + + + align:start position:0% +the stochastic dynamics +okay so so today i want to start talking + + align:start position:0% +okay so so today i want to start talking + + + align:start position:0% +okay so so today i want to start talking +about + + align:start position:0% +about + + + align:start position:0% +about +i want to start breaking down our + + align:start position:0% +i want to start breaking down our + + + align:start position:0% +i want to start breaking down our +assumptions and throughout the rest of + + align:start position:0% +assumptions and throughout the rest of + + + align:start position:0% +assumptions and throughout the rest of +the class we're sort of going to try to + + align:start position:0% +the class we're sort of going to try to + + + align:start position:0% +the class we're sort of going to try to +break these down + + align:start position:0% +break these down + + + align:start position:0% +break these down +um + + align:start position:0% +um + + + align:start position:0% +um +let's start breaking down the assumption + + align:start position:0% +let's start breaking down the assumption + + + align:start position:0% +let's start breaking down the assumption +of deterministic + + align:start position:0% +of deterministic + + + align:start position:0% +of deterministic +dynamics okay + + align:start position:0% + + + + align:start position:0% + +couldn't we actually saw something like + + align:start position:0% +couldn't we actually saw something like + + + align:start position:0% +couldn't we actually saw something like +if we actually have a stochastic + + align:start position:0% +if we actually have a stochastic + + + align:start position:0% +if we actually have a stochastic +transition model and we move somewhere + + align:start position:0% +transition model and we move somewhere + + + align:start position:0% +transition model and we move somewhere +and then we're like a little bit off + + align:start position:0% +and then we're like a little bit off + + + align:start position:0% +and then we're like a little bit off +from the trajectory then we look at the + + align:start position:0% +from the trajectory then we look at the + + + align:start position:0% +from the trajectory then we look at the +policy which would bring this practice + + align:start position:0% +policy which would bring this practice + + + align:start position:0% +policy which would bring this practice +nomination and go back + + align:start position:0% + + + + align:start position:0% + +i think the answer to your question is + + align:start position:0% +i think the answer to your question is + + + align:start position:0% +i think the answer to your question is +yes so one of the things we're going to + + align:start position:0% +yes so one of the things we're going to + + + align:start position:0% +yes so one of the things we're going to +do today is show that the + + align:start position:0% +do today is show that the + + + align:start position:0% +do today is show that the +it's sort of subtle that that's yes but + + align:start position:0% +it's sort of subtle that that's yes but + + + align:start position:0% +it's sort of subtle that that's yes but +anybody who knows linear quadratic + + align:start position:0% +anybody who knows linear quadratic + + + align:start position:0% +anybody who knows linear quadratic +gaussian control + + align:start position:0% +gaussian control + + + align:start position:0% +gaussian control +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +well it turns out that we're actually + + align:start position:0% +well it turns out that we're actually + + + align:start position:0% +well it turns out that we're actually +doing linear quadratic gaussian control + + align:start position:0% +doing linear quadratic gaussian control + + + align:start position:0% +doing linear quadratic gaussian control +but that's that's sort of a surprising + + align:start position:0% +but that's that's sort of a surprising + + + align:start position:0% +but that's that's sort of a surprising +result + + align:start position:0% +result + + + align:start position:0% +result +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so um + + align:start position:0% +so um + + + align:start position:0% +so um +in the specific case of linear dynamics + + align:start position:0% +in the specific case of linear dynamics + + + align:start position:0% +in the specific case of linear dynamics +quadratic cost gaussian noise then what + + align:start position:0% +quadratic cost gaussian noise then what + + + align:start position:0% +quadratic cost gaussian noise then what +you said is true + + align:start position:0% +you said is true + + + align:start position:0% +you said is true +so that's a special case that that we'll + + align:start position:0% +so that's a special case that that we'll + + + align:start position:0% +so that's a special case that that we'll +we'll see + + align:start position:0% +we'll see + + + align:start position:0% +we'll see +quickly um but + + align:start position:0% +quickly um but + + + align:start position:0% +quickly um but +in general it's not true + + align:start position:0% + + + + align:start position:0% + +right so so + + align:start position:0% +right so so + + + align:start position:0% +right so so +and again this is leading into + + align:start position:0% +and again this is leading into + + + align:start position:0% +and again this is leading into +next week we're going to start talking + + align:start position:0% +next week we're going to start talking + + + align:start position:0% +next week we're going to start talking +about + + align:start position:0% +about + + + align:start position:0% +about +doing these + + align:start position:0% +doing these + + + align:start position:0% +doing these +optimal control derivations without any + + align:start position:0% +optimal control derivations without any + + + align:start position:0% +optimal control derivations without any +model + + align:start position:0% +model + + + align:start position:0% +model +but today let's think about what happens + + align:start position:0% +but today let's think about what happens + + + align:start position:0% +but today let's think about what happens +if we have a stochastic model + + align:start position:0% + + + + align:start position:0% + +okay lots of ways people there's lots of + + align:start position:0% +okay lots of ways people there's lots of + + + align:start position:0% +okay lots of ways people there's lots of +different notations people use to talk + + align:start position:0% +different notations people use to talk + + + align:start position:0% +different notations people use to talk +about stochastic dynamics the one i'll + + align:start position:0% +about stochastic dynamics the one i'll + + + align:start position:0% +about stochastic dynamics the one i'll +use is i think the most popular one we + + align:start position:0% +use is i think the most popular one we + + + align:start position:0% +use is i think the most popular one we +want we still got our + + align:start position:0% + + + + align:start position:0% + +our standard + + align:start position:0% +our standard + + + align:start position:0% +our standard +equations of motion + + align:start position:0% +equations of motion + + + align:start position:0% +equations of motion +but we're going to add an additional + + align:start position:0% +but we're going to add an additional + + + align:start position:0% +but we're going to add an additional +input which is + + align:start position:0% +input which is + + + align:start position:0% +input which is +some disturbance w + + align:start position:0% +some disturbance w + + + align:start position:0% +some disturbance w +as an additional input into our dynamics + + align:start position:0% +as an additional input into our dynamics + + + align:start position:0% +as an additional input into our dynamics +where w of t + + align:start position:0% + + + + align:start position:0% + +is some noise process + + align:start position:0% + + + + align:start position:0% + +okay but if we let the noise come in + + align:start position:0% +okay but if we let the noise come in + + + align:start position:0% +okay but if we let the noise come in +through an input here then we can still + + align:start position:0% +through an input here then we can still + + + align:start position:0% +through an input here then we can still +think about it as a deterministic + + align:start position:0% +think about it as a deterministic + + + align:start position:0% +think about it as a deterministic +function our dynamics is a deterministic + + align:start position:0% +function our dynamics is a deterministic + + + align:start position:0% +function our dynamics is a deterministic +function and keep it mostly the same as + + align:start position:0% +function and keep it mostly the same as + + + align:start position:0% +function and keep it mostly the same as +what we've been thinking about + + align:start position:0% +what we've been thinking about + + + align:start position:0% +what we've been thinking about +now some people don't + + align:start position:0% +now some people don't + + + align:start position:0% +now some people don't +like defining noise processes in + + align:start position:0% +like defining noise processes in + + + align:start position:0% +like defining noise processes in +continuous time + + align:start position:0% + + + + align:start position:0% + +it's a little bit more natural to + + align:start position:0% +it's a little bit more natural to + + + align:start position:0% +it's a little bit more natural to +describe them in + + align:start position:0% +describe them in + + + align:start position:0% +describe them in +in discrete time and and as we've done + + align:start position:0% +in discrete time and and as we've done + + + align:start position:0% +in discrete time and and as we've done +in the other class let's do the sort of + + align:start position:0% +in the other class let's do the sort of + + + align:start position:0% +in the other class let's do the sort of +discrete time case first so in discrete + + align:start position:0% +discrete time case first so in discrete + + + align:start position:0% +discrete time case first so in discrete +time + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% + + + + align:start position:0% + +we'll do + + align:start position:0% + + + + align:start position:0% + +the same thing right + + align:start position:0% + + + + align:start position:0% + +but now it's maybe we can um + + align:start position:0% +but now it's maybe we can um + + + align:start position:0% +but now it's maybe we can um +we can it's easier to think about what + + align:start position:0% +we can it's easier to think about what + + + align:start position:0% +we can it's easier to think about what +wn might be so for instance w + + align:start position:0% +wn might be so for instance w + + + align:start position:0% +wn might be so for instance w +then might be some + + align:start position:0% +then might be some + + + align:start position:0% +then might be some +iid + + align:start position:0% +iid + + + align:start position:0% +iid +gaussian process or something like that + + align:start position:0% +gaussian process or something like that + + + align:start position:0% +gaussian process or something like that +right + + align:start position:0% + + + + align:start position:0% + +which + + align:start position:0% +which + + + align:start position:0% +which +is just a + + align:start position:0% +is just a + + + align:start position:0% +is just a +complicated way to say that + + align:start position:0% + + + + align:start position:0% + +at each + + align:start position:0% +at each + + + align:start position:0% +at each +n + + align:start position:0% +n + + + align:start position:0% +n +w and + + align:start position:0% +w and + + + align:start position:0% +w and +is is sampled + + align:start position:0% +is is sampled + + + align:start position:0% +is is sampled +independently + + align:start position:0% + + + + align:start position:0% + +from a gaussian + + align:start position:0% +from a gaussian + + + align:start position:0% +from a gaussian +i'll say a normal distribution + + align:start position:0% +i'll say a normal distribution + + + align:start position:0% +i'll say a normal distribution +like something like that + + align:start position:0% +like something like that + + + align:start position:0% +like something like that +so when i'm simulating this in matlab if + + align:start position:0% +so when i'm simulating this in matlab if + + + align:start position:0% +so when i'm simulating this in matlab if +i have + + align:start position:0% +i have + + + align:start position:0% +i have +you know i can i can simulate an iid + + align:start position:0% +you know i can i can simulate an iid + + + align:start position:0% +you know i can i can simulate an iid +gaussian process by just every every + + align:start position:0% +gaussian process by just every every + + + align:start position:0% +gaussian process by just every every +time step calling rand and yeah as if + + align:start position:0% +time step calling rand and yeah as if + + + align:start position:0% +time step calling rand and yeah as if +and it's independent from the w's i + + align:start position:0% +and it's independent from the w's i + + + align:start position:0% +and it's independent from the w's i +picked before + + align:start position:0% +picked before + + + align:start position:0% +picked before +that's a pretty good model + + align:start position:0% +that's a pretty good model + + + align:start position:0% +that's a pretty good model +now one thing i want to i want to + + align:start position:0% +now one thing i want to i want to + + + align:start position:0% +now one thing i want to i want to +avoid talking about today so far + + align:start position:0% +avoid talking about today so far + + + align:start position:0% +avoid talking about today so far +is let's still assume that we have um + + align:start position:0% + + + + align:start position:0% + +perfect state information + + align:start position:0% + + + + align:start position:0% + +so i don't want to worry about sensor + + align:start position:0% +so i don't want to worry about sensor + + + align:start position:0% +so i don't want to worry about sensor +noise yet it turns out it'll be + + align:start position:0% +noise yet it turns out it'll be + + + align:start position:0% +noise yet it turns out it'll be +pretty natural to think about it with + + align:start position:0% +pretty natural to think about it with + + + align:start position:0% +pretty natural to think about it with +some of the same tools but let's just + + align:start position:0% +some of the same tools but let's just + + + align:start position:0% +some of the same tools but let's just +assume for now that when i'm in state x + + align:start position:0% +assume for now that when i'm in state x + + + align:start position:0% +assume for now that when i'm in state x +i know i'm in state x exactly + + align:start position:0% +i know i'm in state x exactly + + + align:start position:0% +i know i'm in state x exactly +but if i'm trying to think about into + + align:start position:0% +but if i'm trying to think about into + + + align:start position:0% +but if i'm trying to think about into +the future what's going to happen what's + + align:start position:0% +the future what's going to happen what's + + + align:start position:0% +the future what's going to happen what's +the optimal thing to do i have to worry + + align:start position:0% +the optimal thing to do i have to worry + + + align:start position:0% +the optimal thing to do i have to worry +about the fact that + + align:start position:0% +about the fact that + + + align:start position:0% +about the fact that +the noise + + align:start position:0% +the noise + + + align:start position:0% +the noise +in the system is going to push me around + + align:start position:0% + + + + align:start position:0% + +okay so we updated our our + + align:start position:0% +okay so we updated our our + + + align:start position:0% +okay so we updated our our +um + + align:start position:0% +um + + + align:start position:0% +um +our dynamic equation we better start if + + align:start position:0% +our dynamic equation we better start if + + + align:start position:0% +our dynamic equation we better start if +we're thinking about this in an optimal + + align:start position:0% +we're thinking about this in an optimal + + + align:start position:0% +we're thinking about this in an optimal +control + + align:start position:0% +control + + + align:start position:0% +control +um since we better also update our + + align:start position:0% +um since we better also update our + + + align:start position:0% +um since we better also update our +definition for optimality right + + align:start position:0% + + + + align:start position:0% + +so we it used to be + + align:start position:0% + + + + align:start position:0% + +that we said j in the in the discrete + + align:start position:0% +that we said j in the in the discrete + + + align:start position:0% +that we said j in the in the discrete +time case was just some sum from + + align:start position:0% +time case was just some sum from + + + align:start position:0% +time case was just some sum from +n equals 0 to n + + align:start position:0% +n equals 0 to n + + + align:start position:0% +n equals 0 to n +of g + + align:start position:0% +of g + + + align:start position:0% +of g +x n + + align:start position:0% +x n + + + align:start position:0% +x n +u n + + align:start position:0% + + + + align:start position:0% + +the problem with that now is that + + align:start position:0% +the problem with that now is that + + + align:start position:0% +the problem with that now is that +x n + + align:start position:0% +x n + + + align:start position:0% +x n +right this is going to be this is now a + + align:start position:0% +right this is going to be this is now a + + + align:start position:0% +right this is going to be this is now a +random process yeah + + align:start position:0% + + + + align:start position:0% + +if i run + + align:start position:0% + + + + align:start position:0% + +from the same initial conditions + + align:start position:0% +from the same initial conditions + + + align:start position:0% +from the same initial conditions +with even the same open loop tape let's + + align:start position:0% +with even the same open loop tape let's + + + align:start position:0% +with even the same open loop tape let's +say + + align:start position:0% +say + + + align:start position:0% +say +the system + + align:start position:0% +the system + + + align:start position:0% +the system +five times + + align:start position:0% +five times + + + align:start position:0% +five times +this is going to be a different + + align:start position:0% +this is going to be a different + + + align:start position:0% +this is going to be a different +value every time i run it exit time + + align:start position:0% +value every time i run it exit time + + + align:start position:0% +value every time i run it exit time +three will be different on every time i + + align:start position:0% +three will be different on every time i + + + align:start position:0% +three will be different on every time i +run it + + align:start position:0% +run it + + + align:start position:0% +run it +okay which means j is also going to be a + + align:start position:0% +okay which means j is also going to be a + + + align:start position:0% +okay which means j is also going to be a +random variable + + align:start position:0% +random variable + + + align:start position:0% +random variable +or random + + align:start position:0% + + + + align:start position:0% + +so it doesn't quite make sense + + align:start position:0% +so it doesn't quite make sense + + + align:start position:0% +so it doesn't quite make sense +to say + + align:start position:0% +to say + + + align:start position:0% +to say +um + + align:start position:0% +um + + + align:start position:0% +um +my notion of optimality is is some + + align:start position:0% +my notion of optimality is is some + + + align:start position:0% +my notion of optimality is is some +random variable + + align:start position:0% + + + + align:start position:0% + +we want to choose a property of that + + align:start position:0% +we want to choose a property of that + + + align:start position:0% +we want to choose a property of that +random variable that we care about + + align:start position:0% +random variable that we care about + + + align:start position:0% +random variable that we care about +there's different schools again being + + align:start position:0% +there's different schools again being + + + align:start position:0% +there's different schools again being +philosophical a little bit there's + + align:start position:0% +philosophical a little bit there's + + + align:start position:0% +philosophical a little bit there's +different schools of thought and control + + align:start position:0% +different schools of thought and control + + + align:start position:0% +different schools of thought and control +theory right + + align:start position:0% +theory right + + + align:start position:0% +theory right +some people say the thing you should + + align:start position:0% +some people say the thing you should + + + align:start position:0% +some people say the thing you should +care about the only thing you should + + align:start position:0% +care about the only thing you should + + + align:start position:0% +care about the only thing you should +worry about is the worst case behavior + + align:start position:0% +worry about is the worst case behavior + + + align:start position:0% +worry about is the worst case behavior +you want to worry about the tales of + + align:start position:0% +you want to worry about the tales of + + + align:start position:0% +you want to worry about the tales of +your distributions right and make + + align:start position:0% +your distributions right and make + + + align:start position:0% +your distributions right and make +absolutely sure that my plane if i'm + + align:start position:0% +absolutely sure that my plane if i'm + + + align:start position:0% +absolutely sure that my plane if i'm +riding on a plane from here to + + align:start position:0% +riding on a plane from here to + + + align:start position:0% +riding on a plane from here to +california + + align:start position:0% +california + + + align:start position:0% +california +it's not going to fall out of the sky + + align:start position:0% +it's not going to fall out of the sky + + + align:start position:0% +it's not going to fall out of the sky +with sort of + + align:start position:0% +with sort of + + + align:start position:0% +with sort of +five nines of probabilities + + align:start position:0% +five nines of probabilities + + + align:start position:0% +five nines of probabilities +okay + + align:start position:0% +okay + + + align:start position:0% +okay +i actually don't subscribe okay when i'm + + align:start position:0% +i actually don't subscribe okay when i'm + + + align:start position:0% +i actually don't subscribe okay when i'm +riding on a plane i do subscribe to that + + align:start position:0% +riding on a plane i do subscribe to that + + + align:start position:0% +riding on a plane i do subscribe to that +okay but when i'm building robots that i + + align:start position:0% +okay but when i'm building robots that i + + + align:start position:0% +okay but when i'm building robots that i +don't have to + + align:start position:0% +don't have to + + + align:start position:0% +don't have to +you know put my life in jeopardy for uh + + align:start position:0% +you know put my life in jeopardy for uh + + + align:start position:0% +you know put my life in jeopardy for uh +i don't believe in that and i actually + + align:start position:0% +i don't believe in that and i actually + + + align:start position:0% +i don't believe in that and i actually +don't think animals do that i think if + + align:start position:0% +don't think animals do that i think if + + + align:start position:0% +don't think animals do that i think if +animals were so conservative so that's + + align:start position:0% +animals were so conservative so that's + + + align:start position:0% +animals were so conservative so that's +the robust control approach what i just + + align:start position:0% +the robust control approach what i just + + + align:start position:0% +the robust control approach what i just +described the worrying about the worst + + align:start position:0% +described the worrying about the worst + + + align:start position:0% +described the worrying about the worst +case + + align:start position:0% +case + + + align:start position:0% +case +and the problem with robust control the + + align:start position:0% +and the problem with robust control the + + + align:start position:0% +and the problem with robust control the +well documented well discussed problem + + align:start position:0% +well documented well discussed problem + + + align:start position:0% +well documented well discussed problem +with robust control is it tends to come + + align:start position:0% +with robust control is it tends to come + + + align:start position:0% +with robust control is it tends to come +up with conservative control strategies + + align:start position:0% +up with conservative control strategies + + + align:start position:0% +up with conservative control strategies +right + + align:start position:0% +right + + + align:start position:0% +right +so if i'm worried about you know never + + align:start position:0% +so if i'm worried about you know never + + + align:start position:0% +so if i'm worried about you know never +running to a table then i'm never going + + align:start position:0% +running to a table then i'm never going + + + align:start position:0% +running to a table then i'm never going +to go anywhere near that table right + + align:start position:0% + + + + align:start position:0% + +there's another approach + + align:start position:0% +there's another approach + + + align:start position:0% +there's another approach +which i prefer that tends to go to be + + align:start position:0% +which i prefer that tends to go to be + + + align:start position:0% +which i prefer that tends to go to be +more common in the optimal control + + align:start position:0% +more common in the optimal control + + + align:start position:0% +more common in the optimal control +community is to worry about maximizing + + align:start position:0% +community is to worry about maximizing + + + align:start position:0% +community is to worry about maximizing +the expected returns okay + + align:start position:0% +the expected returns okay + + + align:start position:0% +the expected returns okay +so now let's + + align:start position:0% + + + + align:start position:0% + +let's define + + align:start position:0% +let's define + + + align:start position:0% +let's define +j + + align:start position:0% +j + + + align:start position:0% +j +as the expected value + + align:start position:0% +as the expected value + + + align:start position:0% +as the expected value +of this + + align:start position:0% +of this + + + align:start position:0% +of this +cost function + + align:start position:0% + + + + align:start position:0% + +right + + align:start position:0% + + + + align:start position:0% + +there's a really obvious reason why the + + align:start position:0% +there's a really obvious reason why the + + + align:start position:0% +there's a really obvious reason why the +optimal control people choose to do that + + align:start position:0% +optimal control people choose to do that + + + align:start position:0% +optimal control people choose to do that +it's because we already made a decision + + align:start position:0% +it's because we already made a decision + + + align:start position:0% +it's because we already made a decision +to do additive costs + + align:start position:0% +to do additive costs + + + align:start position:0% +to do additive costs +expectations play beautifully with + + align:start position:0% +expectations play beautifully with + + + align:start position:0% +expectations play beautifully with +with summations and so our life is going + + align:start position:0% +with summations and so our life is going + + + align:start position:0% +with summations and so our life is going +to stay clean and good if we're willing + + align:start position:0% +to stay clean and good if we're willing + + + align:start position:0% +to stay clean and good if we're willing +to do the expected value + + align:start position:0% +to do the expected value + + + align:start position:0% +to do the expected value +derivations okay + + align:start position:0% +derivations okay + + + align:start position:0% +derivations okay +but also philosophically i think that + + align:start position:0% +but also philosophically i think that + + + align:start position:0% +but also philosophically i think that +that + + align:start position:0% +that + + + align:start position:0% +that +me as an animal i maximize my expected + + align:start position:0% +me as an animal i maximize my expected + + + align:start position:0% +me as an animal i maximize my expected +reward gazelle running through the field + + align:start position:0% +reward gazelle running through the field + + + align:start position:0% +reward gazelle running through the field +you know i think + + align:start position:0% +you know i think + + + align:start position:0% +you know i think +is maximizing expected reward i mean on + + align:start position:0% +is maximizing expected reward i mean on + + + align:start position:0% +is maximizing expected reward i mean on +average + + align:start position:0% +average + + + align:start position:0% +average +it's doing spectacularly well right + + align:start position:0% +it's doing spectacularly well right + + + align:start position:0% +it's doing spectacularly well right +and every once in a while it wipes out + + align:start position:0% +and every once in a while it wipes out + + + align:start position:0% +and every once in a while it wipes out +and falls down and breaks its leg gets + + align:start position:0% +and falls down and breaks its leg gets + + + align:start position:0% +and falls down and breaks its leg gets +eaten you know uh but but if it was + + align:start position:0% +eaten you know uh but but if it was + + + align:start position:0% +eaten you know uh but but if it was +worrying about that all the time then it + + align:start position:0% +worrying about that all the time then it + + + align:start position:0% +worrying about that all the time then it +would never run you know it as fast as + + align:start position:0% +would never run you know it as fast as + + + align:start position:0% +would never run you know it as fast as +it does + + align:start position:0% +it does + + + align:start position:0% +it does +so or as aggressively as it does + + align:start position:0% +so or as aggressively as it does + + + align:start position:0% +so or as aggressively as it does +so i think personally if you want to + + align:start position:0% +so i think personally if you want to + + + align:start position:0% +so i think personally if you want to +build aggressive robots right you've got + + align:start position:0% +build aggressive robots right you've got + + + align:start position:0% +build aggressive robots right you've got +to stop worrying about guarantees of + + align:start position:0% +to stop worrying about guarantees of + + + align:start position:0% +to stop worrying about guarantees of +stability of performance just try to + + align:start position:0% +stability of performance just try to + + + align:start position:0% +stability of performance just try to +maximize the average performance i think + + align:start position:0% +maximize the average performance i think + + + align:start position:0% +maximize the average performance i think +that's + + align:start position:0% +that's + + + align:start position:0% +that's +that's where i've put my chips + + align:start position:0% + + + + align:start position:0% + +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +so now just to be clear here so so x + + align:start position:0% +so now just to be clear here so so x + + + align:start position:0% +so now just to be clear here so so x +again every time i run it even with a + + align:start position:0% +again every time i run it even with a + + + align:start position:0% +again every time i run it even with a +an open loop u if i completely control u + + align:start position:0% +an open loop u if i completely control u + + + align:start position:0% +an open loop u if i completely control u +so u is not a random variable but a + + align:start position:0% +so u is not a random variable but a + + + align:start position:0% +so u is not a random variable but a +some open loop tape let's say + + align:start position:0% +some open loop tape let's say + + + align:start position:0% +some open loop tape let's say +x will still be a random variable + + align:start position:0% +x will still be a random variable + + + align:start position:0% +x will still be a random variable +okay but + + align:start position:0% +okay but + + + align:start position:0% +okay but +j is not right j is saying that given + + align:start position:0% +j is not right j is saying that given + + + align:start position:0% +j is not right j is saying that given +some control policy some initial + + align:start position:0% +some control policy some initial + + + align:start position:0% +some control policy some initial +conditions there is a + + align:start position:0% +conditions there is a + + + align:start position:0% +conditions there is a +well-defined cost that i expected cost + + align:start position:0% +well-defined cost that i expected cost + + + align:start position:0% +well-defined cost that i expected cost +that i receive and that's something i + + align:start position:0% +that i receive and that's something i + + + align:start position:0% +that i receive and that's something i +can optimize okay + + align:start position:0% + + + + align:start position:0% + +does that make sense + + align:start position:0% +does that make sense + + + align:start position:0% +does that make sense +okay so um + + align:start position:0% +okay so um + + + align:start position:0% +okay so um +i want to think about the implications + + align:start position:0% +i want to think about the implications + + + align:start position:0% +i want to think about the implications +of having + + align:start position:0% +of having + + + align:start position:0% +of having +these things turn into random variables + + align:start position:0% +these things turn into random variables + + + align:start position:0% +these things turn into random variables +with sort of a simple example okay + + align:start position:0% +with sort of a simple example okay + + + align:start position:0% +with sort of a simple example okay +um + + align:start position:0% + + + + align:start position:0% + +in that example i like the one i like is + + align:start position:0% +in that example i like the one i like is + + + align:start position:0% +in that example i like the one i like is +a particle + + align:start position:0% +a particle + + + align:start position:0% +a particle +sitting in a bowl let's say a some + + align:start position:0% +sitting in a bowl let's say a some + + + align:start position:0% +sitting in a bowl let's say a some +particle in a potential well + + align:start position:0% +particle in a potential well + + + align:start position:0% +particle in a potential well +right so there's let's say gravity is + + align:start position:0% +right so there's let's say gravity is + + + align:start position:0% +right so there's let's say gravity is +like this + + align:start position:0% + + + + align:start position:0% + +and i've got some bowl i'm sitting in + + align:start position:0% +and i've got some bowl i'm sitting in + + + align:start position:0% +and i've got some bowl i'm sitting in +and this particle is going to + + align:start position:0% +and this particle is going to + + + align:start position:0% +and this particle is going to +want to roll down that bowl + + align:start position:0% +want to roll down that bowl + + + align:start position:0% +want to roll down that bowl +okay but to make it interesting we're + + align:start position:0% +okay but to make it interesting we're + + + align:start position:0% +okay but to make it interesting we're +going to say that this particle is + + align:start position:0% +going to say that this particle is + + + align:start position:0% +going to say that this particle is +subject to brownian motion right do you + + align:start position:0% +subject to brownian motion right do you + + + align:start position:0% +subject to brownian motion right do you +guys know what brownie in motion is + + align:start position:0% + + + + align:start position:0% + +i guess + + align:start position:0% + + + + align:start position:0% + +i guess if you look down at a at a petri + + align:start position:0% +i guess if you look down at a at a petri + + + align:start position:0% +i guess if you look down at a at a petri +dish of some of very small things + + align:start position:0% +dish of some of very small things + + + align:start position:0% +dish of some of very small things +they don't sit still there's + + align:start position:0% +they don't sit still there's + + + align:start position:0% +they don't sit still there's +a debate about exactly the physical + + align:start position:0% +a debate about exactly the physical + + + align:start position:0% +a debate about exactly the physical +mechanisms of it but phenomenologically + + align:start position:0% +mechanisms of it but phenomenologically + + + align:start position:0% +mechanisms of it but phenomenologically +you can see you know a very small cells + + align:start position:0% +you can see you know a very small cells + + + align:start position:0% +you can see you know a very small cells +that are not actively um motile by + + align:start position:0% +that are not actively um motile by + + + align:start position:0% +that are not actively um motile by +themselves sort of move around in a + + align:start position:0% +themselves sort of move around in a + + + align:start position:0% +themselves sort of move around in a +random in a random fashion doing random + + align:start position:0% +random in a random fashion doing random + + + align:start position:0% +random in a random fashion doing random +walks and things like this so people um + + align:start position:0% +walks and things like this so people um + + + align:start position:0% +walks and things like this so people um +i won't get into the + + align:start position:0% +i won't get into the + + + align:start position:0% +i won't get into the +sort of philosophy of uh the + + align:start position:0% +sort of philosophy of uh the + + + align:start position:0% +sort of philosophy of uh the +philosophical debate of whether + + align:start position:0% +philosophical debate of whether + + + align:start position:0% +philosophical debate of whether +you know there exists stochasticity in + + align:start position:0% +you know there exists stochasticity in + + + align:start position:0% +you know there exists stochasticity in +the world but i think stochasticity is + + align:start position:0% +the world but i think stochasticity is + + + align:start position:0% +the world but i think stochasticity is +certainly a relevant model for a lot of + + align:start position:0% +certainly a relevant model for a lot of + + + align:start position:0% +certainly a relevant model for a lot of +things we're doing here + + align:start position:0% +things we're doing here + + + align:start position:0% +things we're doing here +yeah we don't want to get quantum + + align:start position:0% +yeah we don't want to get quantum + + + align:start position:0% +yeah we don't want to get quantum +in class + + align:start position:0% +in class + + + align:start position:0% +in class +okay but let's just say that this guy is + + align:start position:0% +okay but let's just say that this guy is + + + align:start position:0% +okay but let's just say that this guy is +is subject to the dynamics of this bowl + + align:start position:0% +is subject to the dynamics of this bowl + + + align:start position:0% +is subject to the dynamics of this bowl +but on top of that dynamics of this bowl + + align:start position:0% +but on top of that dynamics of this bowl + + + align:start position:0% +but on top of that dynamics of this bowl +it has a tendency to jitter around a + + align:start position:0% +it has a tendency to jitter around a + + + align:start position:0% +it has a tendency to jitter around a +little bit + + align:start position:0% +little bit + + + align:start position:0% +little bit +okay so i'll write down the dynamics + + align:start position:0% +okay so i'll write down the dynamics + + + align:start position:0% +okay so i'll write down the dynamics +i'll keep it discrete for now so let's + + align:start position:0% +i'll keep it discrete for now so let's + + + align:start position:0% +i'll keep it discrete for now so let's +say um + + align:start position:0% +say um + + + align:start position:0% +say um +on every time step the difference you + + align:start position:0% +on every time step the difference you + + + align:start position:0% +on every time step the difference you +know the update + + align:start position:0% +know the update + + + align:start position:0% +know the update +it looks like + + align:start position:0% +it looks like + + + align:start position:0% +it looks like +the gradient of that bowl + + align:start position:0% +the gradient of that bowl + + + align:start position:0% +the gradient of that bowl +it's trying to get go down that bowl + + align:start position:0% + + + + align:start position:0% + +plus some random noise + + align:start position:0% +plus some random noise + + + align:start position:0% +plus some random noise +i'll call it z + + align:start position:0% +i'll call it z + + + align:start position:0% +i'll call it z +of n and this again i'll assume is + + align:start position:0% +of n and this again i'll assume is + + + align:start position:0% +of n and this again i'll assume is +iid + + align:start position:0% +iid + + + align:start position:0% +iid +independent identically distributed + + align:start position:0% +independent identically distributed + + + align:start position:0% +independent identically distributed +gaussian + + align:start position:0% + + + + align:start position:0% + +noise + + align:start position:0% + + + + align:start position:0% + +so if you've never taken a class with + + align:start position:0% +so if you've never taken a class with + + + align:start position:0% +so if you've never taken a class with +all this + + align:start position:0% +all this + + + align:start position:0% +all this +random variables and everything i hope + + align:start position:0% +random variables and everything i hope + + + align:start position:0% +random variables and everything i hope +most of this will still come through + + align:start position:0% +most of this will still come through + + + align:start position:0% +most of this will still come through +i'll throw a few of these words and try + + align:start position:0% +i'll throw a few of these words and try + + + align:start position:0% +i'll throw a few of these words and try +to be soft about it if you have + + align:start position:0% +to be soft about it if you have + + + align:start position:0% +to be soft about it if you have +questions about any of these just ask me + + align:start position:0% +questions about any of these just ask me + + + align:start position:0% +questions about any of these just ask me +i think + + align:start position:0% +i think + + + align:start position:0% +i think +that we're going to be able to say + + align:start position:0% +that we're going to be able to say + + + align:start position:0% +that we're going to be able to say +things that are fairly mechanically + + align:start position:0% +things that are fairly mechanically + + + align:start position:0% +things that are fairly mechanically +intuitive and and helpful so so i hope + + align:start position:0% +intuitive and and helpful so so i hope + + + align:start position:0% +intuitive and and helpful so so i hope +it's accessible to everybody and if it's + + align:start position:0% +it's accessible to everybody and if it's + + + align:start position:0% +it's accessible to everybody and if it's +not ask me + + align:start position:0% + + + + align:start position:0% + +okay so this is a reasonable + + align:start position:0% +okay so this is a reasonable + + + align:start position:0% +okay so this is a reasonable +um + + align:start position:0% +um + + + align:start position:0% +um +dynamical system now it's going it's + + align:start position:0% +dynamical system now it's going it's + + + align:start position:0% +dynamical system now it's going it's +tempting to on each update having gone + + align:start position:0% +tempting to on each update having gone + + + align:start position:0% +tempting to on each update having gone +down the gradient plus + + align:start position:0% +down the gradient plus + + + align:start position:0% +down the gradient plus +plus some random noise okay + + align:start position:0% +plus some random noise okay + + + align:start position:0% +plus some random noise okay +let's make the our lives easier by + + align:start position:0% +let's make the our lives easier by + + + align:start position:0% +let's make the our lives easier by +choosing + + align:start position:0% + + + + align:start position:0% + +u of x to be + + align:start position:0% + + + + align:start position:0% + +how about that that's pretty nice right + + align:start position:0% + + + + align:start position:0% + +that makes it makes our life good if + + align:start position:0% +that makes it makes our life good if + + + align:start position:0% +that makes it makes our life good if +everything's quadratic then this thing + + align:start position:0% +everything's quadratic then this thing + + + align:start position:0% +everything's quadratic then this thing +turns out to be + + align:start position:0% +turns out to be + + + align:start position:0% +turns out to be +negative alpha x right + + align:start position:0% + + + + align:start position:0% + +okay so just to make sure we're we're + + align:start position:0% +okay so just to make sure we're we're + + + align:start position:0% +okay so just to make sure we're we're +thinking about it if the noise is zero + + align:start position:0% +thinking about it if the noise is zero + + + align:start position:0% +thinking about it if the noise is zero +then what's going to happen + + align:start position:0% +then what's going to happen + + + align:start position:0% +then what's going to happen +in this system i've got a + + align:start position:0% + + + + align:start position:0% + +i've got a + + align:start position:0% +i've got a + + + align:start position:0% +i've got a +discrete time system + + align:start position:0% +discrete time system + + + align:start position:0% +discrete time system +which if i move that back over the other + + align:start position:0% +which if i move that back over the other + + + align:start position:0% +which if i move that back over the other +side like we're accustomed to + + align:start position:0% +side like we're accustomed to + + + align:start position:0% +side like we're accustomed to +goes like this + + align:start position:0% + + + + align:start position:0% + +right + + align:start position:0% +right + + + align:start position:0% +right +so what's how does that thing behave + + align:start position:0% + + + + align:start position:0% + +where's the fixed point + + align:start position:0% + + + + align:start position:0% + +at zero + + align:start position:0% +at zero + + + align:start position:0% +at zero +and when is it stable + + align:start position:0% + + + + align:start position:0% + +when's it stable + + align:start position:0% +when's it stable + + + align:start position:0% +when's it stable +discrete time linear system + + align:start position:0% + + + + align:start position:0% + +yep + + align:start position:0% + + + + align:start position:0% + +no you're thinking too continuous + + align:start position:0% +no you're thinking too continuous + + + align:start position:0% +no you're thinking too continuous +time + + align:start position:0% +time + + + align:start position:0% +time +in discrete time your bounds on your + + align:start position:0% +in discrete time your bounds on your + + + align:start position:0% +in discrete time your bounds on your +eigenvalues + + align:start position:0% +eigenvalues + + + align:start position:0% +eigenvalues +are + + align:start position:0% +are + + + align:start position:0% +are +between they have to be the absolute + + align:start position:0% +between they have to be the absolute + + + align:start position:0% +between they have to be the absolute +value has to be less than one right + + align:start position:0% +value has to be less than one right + + + align:start position:0% +value has to be less than one right +which i think in this case means alpha's + + align:start position:0% +which i think in this case means alpha's + + + align:start position:0% +which i think in this case means alpha's +got to be + + align:start position:0% + + + + align:start position:0% + +between zero and two yeah + + align:start position:0% + + + + align:start position:0% + +everybody okay with it yeah + + align:start position:0% +everybody okay with it yeah + + + align:start position:0% +everybody okay with it yeah +that wasn't supposed to be the + + align:start position:0% +that wasn't supposed to be the + + + align:start position:0% +that wasn't supposed to be the +big insight for the lecture but + + align:start position:0% +big insight for the lecture but + + + align:start position:0% +big insight for the lecture but +um + + align:start position:0% + + + + align:start position:0% + +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +um + + align:start position:0% +um + + + align:start position:0% +um +so the reason i wanted to say that okay + + align:start position:0% +so the reason i wanted to say that okay + + + align:start position:0% +so the reason i wanted to say that okay +so we definitely have some stable + + align:start position:0% +so we definitely have some stable + + + align:start position:0% +so we definitely have some stable +dynamics um pushing us this way in this + + align:start position:0% +dynamics um pushing us this way in this + + + align:start position:0% +dynamics um pushing us this way in this +bowl right that's the the picture tells + + align:start position:0% +bowl right that's the the picture tells + + + align:start position:0% +bowl right that's the the picture tells +you that the the math tells you that + + align:start position:0% +you that the the math tells you that + + + align:start position:0% +you that the the math tells you that +we have some stable dynamics that's + + align:start position:0% +we have some stable dynamics that's + + + align:start position:0% +we have some stable dynamics that's +pushing us towards here + + align:start position:0% +pushing us towards here + + + align:start position:0% +pushing us towards here +and then we have something that's + + align:start position:0% +and then we have something that's + + + align:start position:0% +and then we have something that's +pushing us out which is that noise right + + align:start position:0% +pushing us out which is that noise right + + + align:start position:0% +pushing us out which is that noise right +if i was maybe just as a thought + + align:start position:0% +if i was maybe just as a thought + + + align:start position:0% +if i was maybe just as a thought +exercise if my bowl had been flat if + + align:start position:0% +exercise if my bowl had been flat if + + + align:start position:0% +exercise if my bowl had been flat if +alpha was zero + + align:start position:0% +alpha was zero + + + align:start position:0% +alpha was zero +and i've got this thing subject to + + align:start position:0% +and i've got this thing subject to + + + align:start position:0% +and i've got this thing subject to +brownian motion + + align:start position:0% +brownian motion + + + align:start position:0% +brownian motion +then if i look at it at time you know + + align:start position:0% +then if i look at it at time you know + + + align:start position:0% +then if i look at it at time you know +100 where is it going to be + + align:start position:0% + + + + align:start position:0% + +i mean it could go sort of sort of + + align:start position:0% +i mean it could go sort of sort of + + + align:start position:0% +i mean it could go sort of sort of +anywhere yeah + + align:start position:0% +anywhere yeah + + + align:start position:0% +anywhere yeah +if it's in this bowl + + align:start position:0% +if it's in this bowl + + + align:start position:0% +if it's in this bowl +and it's + + align:start position:0% +and it's + + + align:start position:0% +and it's +um in subject to brownian motion then + + align:start position:0% +um in subject to brownian motion then + + + align:start position:0% +um in subject to brownian motion then +what's it where's it gonna be at time + + align:start position:0% +what's it where's it gonna be at time + + + align:start position:0% +what's it where's it gonna be at time +100. + + align:start position:0% + + + + align:start position:0% + +you'd expect that with high probability + + align:start position:0% +you'd expect that with high probability + + + align:start position:0% +you'd expect that with high probability +to be around here there's a chance i + + align:start position:0% +to be around here there's a chance i + + + align:start position:0% +to be around here there's a chance i +mean even it turns even with small noise + + align:start position:0% +mean even it turns even with small noise + + + align:start position:0% +mean even it turns even with small noise +right if i were to get um some sort of + + align:start position:0% +right if i were to get um some sort of + + + align:start position:0% +right if i were to get um some sort of +some + + align:start position:0% +some + + + align:start position:0% +some +abnormally rare large force in this + + align:start position:0% +abnormally rare large force in this + + + align:start position:0% +abnormally rare large force in this +direction 10 times in a row if i watch + + align:start position:0% +direction 10 times in a row if i watch + + + align:start position:0% +direction 10 times in a row if i watch +this gaussian process long enough you + + align:start position:0% +this gaussian process long enough you + + + align:start position:0% +this gaussian process long enough you +know i might i might look and find it + + align:start position:0% +know i might i might look and find it + + + align:start position:0% +know i might i might look and find it +here but that's going to be very low + + align:start position:0% +here but that's going to be very low + + + align:start position:0% +here but that's going to be very low +probability right + + align:start position:0% +probability right + + + align:start position:0% +probability right +so what i'd expect to find is if i watch + + align:start position:0% +so what i'd expect to find is if i watch + + + align:start position:0% +so what i'd expect to find is if i watch +it for some amount of time and i look at + + align:start position:0% +it for some amount of time and i look at + + + align:start position:0% +it for some amount of time and i look at +it as time as a 100 that it's probably + + align:start position:0% +it as time as a 100 that it's probably + + + align:start position:0% +it as time as a 100 that it's probably +going to be here + + align:start position:0% +going to be here + + + align:start position:0% +going to be here +you know + + align:start position:0% +you know + + + align:start position:0% +you know +draw some probability distribution here + + align:start position:0% +draw some probability distribution here + + + align:start position:0% +draw some probability distribution here +and sure there's some tails here that'll + + align:start position:0% +and sure there's some tails here that'll + + + align:start position:0% +and sure there's some tails here that'll +that'll say if i looked maybe i'll find + + align:start position:0% +that'll say if i looked maybe i'll find + + + align:start position:0% +that'll say if i looked maybe i'll find +it there but that's pretty unlikely + + align:start position:0% +it there but that's pretty unlikely + + + align:start position:0% +it there but that's pretty unlikely +okay so hopefully when we're all done + + align:start position:0% +okay so hopefully when we're all done + + + align:start position:0% +okay so hopefully when we're all done +with this we're going to get that out + + align:start position:0% +with this we're going to get that out + + + align:start position:0% +with this we're going to get that out +it's not too hard to see it actually + + align:start position:0% + + + + align:start position:0% + +so what's the that's the best way to see + + align:start position:0% +so what's the that's the best way to see + + + align:start position:0% +so what's the that's the best way to see +it so let's + + align:start position:0% +it so let's + + + align:start position:0% +it so let's +let's pretend that + + align:start position:0% +let's pretend that + + + align:start position:0% +let's pretend that +we're going back to our so this was the + + align:start position:0% +we're going back to our so this was the + + + align:start position:0% +we're going back to our so this was the +we're back to the noise case again right + + align:start position:0% +we're back to the noise case again right + + + align:start position:0% +we're back to the noise case again right +putting epsilon back in + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% + + + + align:start position:0% + +can we compute then so if i know where i + + align:start position:0% +can we compute then so if i know where i + + + align:start position:0% +can we compute then so if i know where i +am at time n if i've my sensors are + + align:start position:0% +am at time n if i've my sensors are + + + align:start position:0% +am at time n if i've my sensors are +perfect like i said + + align:start position:0% +perfect like i said + + + align:start position:0% +perfect like i said +i know where i am at time n + + align:start position:0% +i know where i am at time n + + + align:start position:0% +i know where i am at time n +where am i going to be at time n plus 1 + + align:start position:0% + + + + align:start position:0% + +so let me let me write that as some + + align:start position:0% +so let me let me write that as some + + + align:start position:0% +so let me let me write that as some +probability distribution that + + align:start position:0% +probability distribution that + + + align:start position:0% +probability distribution that +i want to write where am i at probably + + align:start position:0% +i want to write where am i at probably + + + align:start position:0% +i want to write where am i at probably +at time + + align:start position:0% +at time + + + align:start position:0% +at time +n plus 1 given i'm i know where i am + + align:start position:0% +n plus 1 given i'm i know where i am + + + align:start position:0% +n plus 1 given i'm i know where i am +at time n + + align:start position:0% +at time n + + + align:start position:0% +at time n +what's that going to look like + + align:start position:0% + + + + align:start position:0% + +awesome + + align:start position:0% +awesome + + + align:start position:0% +awesome +right so i'm going to be + + align:start position:0% +right so i'm going to be + + + align:start position:0% +right so i'm going to be +um probably i'm going to be 1 minus + + align:start position:0% +um probably i'm going to be 1 minus + + + align:start position:0% +um probably i'm going to be 1 minus +alpha + + align:start position:0% +alpha + + + align:start position:0% +alpha +xn away from where i was but then some + + align:start position:0% +xn away from where i was but then some + + + align:start position:0% +xn away from where i was but then some +gaussian distribution centered around + + align:start position:0% +gaussian distribution centered around + + + align:start position:0% +gaussian distribution centered around +that point right the deterministic part + + align:start position:0% +that point right the deterministic part + + + align:start position:0% +that point right the deterministic part +puts me here and then this this part + + align:start position:0% +puts me here and then this this part + + + align:start position:0% +puts me here and then this this part +then adds noise to that + + align:start position:0% +then adds noise to that + + + align:start position:0% +then adds noise to that +okay so that's going to be + + align:start position:0% +okay so that's going to be + + + align:start position:0% +okay so that's going to be +you know my full gaussian here + + align:start position:0% +you know my full gaussian here + + + align:start position:0% +you know my full gaussian here +2 pi sigma squared + + align:start position:0% + + + + align:start position:0% + +e to the negative + + align:start position:0% +e to the negative + + + align:start position:0% +e to the negative +x n plus 1 + + align:start position:0% +x n plus 1 + + + align:start position:0% +x n plus 1 +minus 1 minus alpha + + align:start position:0% +minus 1 minus alpha + + + align:start position:0% +minus 1 minus alpha +x n + + align:start position:0% +x n + + + align:start position:0% +x n +that whole thing squared + + align:start position:0% +that whole thing squared + + + align:start position:0% +that whole thing squared +all over 2 sigma squared yeah + + align:start position:0% + + + + align:start position:0% + +you agree with that if i if i know where + + align:start position:0% +you agree with that if i if i know where + + + align:start position:0% +you agree with that if i if i know where +i am + + align:start position:0% +i am + + + align:start position:0% +i am +at time x n + + align:start position:0% +at time x n + + + align:start position:0% +at time x n +which by the way is equivalent + + align:start position:0% +which by the way is equivalent + + + align:start position:0% +which by the way is equivalent +in probability space + + align:start position:0% +in probability space + + + align:start position:0% +in probability space +to saying i have a a delta function here + + align:start position:0% +to saying i have a a delta function here + + + align:start position:0% +to saying i have a a delta function here +right i know where i am + + align:start position:0% +right i know where i am + + + align:start position:0% +right i know where i am +my probability distribution is a delta + + align:start position:0% +my probability distribution is a delta + + + align:start position:0% +my probability distribution is a delta +function + + align:start position:0% + + + + align:start position:0% + +then on the next step i'm going to be + + align:start position:0% +then on the next step i'm going to be + + + align:start position:0% +then on the next step i'm going to be +1 minus alpha times that and i'm going + + align:start position:0% +1 minus alpha times that and i'm going + + + align:start position:0% +1 minus alpha times that and i'm going +to have a distribution which is mean of + + align:start position:0% +to have a distribution which is mean of + + + align:start position:0% +to have a distribution which is mean of +this right this is a gaussian + + align:start position:0% +this right this is a gaussian + + + align:start position:0% +this right this is a gaussian +distribution x minus mu + + align:start position:0% +distribution x minus mu + + + align:start position:0% +distribution x minus mu +over 2 sigma squared + + align:start position:0% +over 2 sigma squared + + + align:start position:0% +over 2 sigma squared +squared + + align:start position:0% +squared + + + align:start position:0% +squared +this is the new x this is mu + + align:start position:0% + + + + align:start position:0% + +good so now we have + + align:start position:0% +good so now we have + + + align:start position:0% +good so now we have +everything we need really to + + align:start position:0% +everything we need really to + + + align:start position:0% +everything we need really to +um + + align:start position:0% +um + + + align:start position:0% +um +to proceed so let's say + + align:start position:0% +to proceed so let's say + + + align:start position:0% +to proceed so let's say +i knew where i was at x + + align:start position:0% +i knew where i was at x + + + align:start position:0% +i knew where i was at x + + align:start position:0% + + + align:start position:0% +on x1 i'm going to be + + align:start position:0% +on x1 i'm going to be + + + align:start position:0% +on x1 i'm going to be +at the function described by this where + + align:start position:0% +at the function described by this where + + + align:start position:0% +at the function described by this where +am i going to be at x2 + + align:start position:0% + + + + align:start position:0% + +in general i have to do + + align:start position:0% +in general i have to do + + + align:start position:0% +in general i have to do +the update and let me + + align:start position:0% +the update and let me + + + align:start position:0% +the update and let me +use the notation + + align:start position:0% +use the notation + + + align:start position:0% +use the notation +p of n plus one meaning the probability + + align:start position:0% +p of n plus one meaning the probability + + + align:start position:0% +p of n plus one meaning the probability +distribution over x at time n plus one + + align:start position:0% +distribution over x at time n plus one + + + align:start position:0% +distribution over x at time n plus one +so think of it as a different function + + align:start position:0% +so think of it as a different function + + + align:start position:0% +so think of it as a different function +at each discrete time + + align:start position:0% +at each discrete time + + + align:start position:0% +at each discrete time +notationally it's the cleanest i think + + align:start position:0% + + + + align:start position:0% + +well that's going to be + + align:start position:0% + + + + align:start position:0% + +it's going to be i have to think about + + align:start position:0% +it's going to be i have to think about + + + align:start position:0% +it's going to be i have to think about +oops i did + + align:start position:0% +oops i did + + + align:start position:0% +oops i did +sorry this is a y yeah + + align:start position:0% +sorry this is a y yeah + + + align:start position:0% +sorry this is a y yeah +my fault + + align:start position:0% + + + + align:start position:0% + +so if i if i was + + align:start position:0% +so if i if i was + + + align:start position:0% +so if i if i was +i have to think about all the + + align:start position:0% +i have to think about all the + + + align:start position:0% +i have to think about all the +possibilities i want the probability + + align:start position:0% +possibilities i want the probability + + + align:start position:0% +possibilities i want the probability +that i was in y equals zero and then the + + align:start position:0% +that i was in y equals zero and then the + + + align:start position:0% +that i was in y equals zero and then the +probability being an x + + align:start position:0% +probability being an x + + + align:start position:0% +probability being an x +considering i was in y zero but also i + + align:start position:0% +considering i was in y zero but also i + + + align:start position:0% +considering i was in y zero but also i +had to think about what if y was one + + align:start position:0% +had to think about what if y was one + + + align:start position:0% +had to think about what if y was one +well what's the probability of that and + + align:start position:0% +well what's the probability of that and + + + align:start position:0% +well what's the probability of that and +i'm going to sum the whole thing up + + align:start position:0% +i'm going to sum the whole thing up + + + align:start position:0% +i'm going to sum the whole thing up +in a continuous way and i'm going to get + + align:start position:0% +in a continuous way and i'm going to get + + + align:start position:0% +in a continuous way and i'm going to get +my new probability of being at the new + + align:start position:0% +my new probability of being at the new + + + align:start position:0% +my new probability of being at the new +place you guys okay with this equation + + align:start position:0% +place you guys okay with this equation + + + align:start position:0% +place you guys okay with this equation +all right i have to consider all + + align:start position:0% +all right i have to consider all + + + align:start position:0% +all right i have to consider all +possible cases of where i was + + align:start position:0% +possible cases of where i was + + + align:start position:0% +possible cases of where i was +at time + + align:start position:0% +at time + + + align:start position:0% +at time +n + + align:start position:0% +n + + + align:start position:0% +n +that's given by this and then apply my + + align:start position:0% +that's given by this and then apply my + + + align:start position:0% +that's given by this and then apply my +dynamics which is given by this to get + + align:start position:0% +dynamics which is given by this to get + + + align:start position:0% +dynamics which is given by this to get +my new distribution + + align:start position:0% +my new distribution + + + align:start position:0% +my new distribution +okay + + align:start position:0% + + + + align:start position:0% + +hope that's okay but even if it's not it + + align:start position:0% +hope that's okay but even if it's not it + + + align:start position:0% +hope that's okay but even if it's not it +should be + + align:start position:0% +should be + + + align:start position:0% +should be +you'll you'll still be okay here in a + + align:start position:0% +you'll you'll still be okay here in a + + + align:start position:0% +you'll you'll still be okay here in a +second + + align:start position:0% + + + + align:start position:0% + +so we can + + align:start position:0% +so we can + + + align:start position:0% +so we can +we can do that right so let's say that + + align:start position:0% +we can do that right so let's say that + + + align:start position:0% +we can do that right so let's say that +p of n + + align:start position:0% +p of n + + + align:start position:0% +p of n +y + + align:start position:0% +y + + + align:start position:0% +y +is a delta function right that's what i + + align:start position:0% +is a delta function right that's what i + + + align:start position:0% +is a delta function right that's what i +said so i know my initial conditions + + align:start position:0% +said so i know my initial conditions + + + align:start position:0% +said so i know my initial conditions +i should have drawn it right here + + align:start position:0% + + + + align:start position:0% + +to match that that plot + + align:start position:0% +to match that that plot + + + align:start position:0% +to match that that plot +well then after one step + + align:start position:0% +well then after one step + + + align:start position:0% +well then after one step +it's going to just pick out the p of + + align:start position:0% +it's going to just pick out the p of + + + align:start position:0% +it's going to just pick out the p of +of uh + + align:start position:0% +of uh + + + align:start position:0% +of uh +this thing this + + align:start position:0% +this thing this + + + align:start position:0% +this thing this +gaussian + + align:start position:0% +gaussian + + + align:start position:0% +gaussian +centered at that y + + align:start position:0% +centered at that y + + + align:start position:0% +centered at that y +and at one step then + + align:start position:0% +and at one step then + + + align:start position:0% +and at one step then +i'm going to be at a gaussian + + align:start position:0% +i'm going to be at a gaussian + + + align:start position:0% +i'm going to be at a gaussian +distribution + + align:start position:0% + + + + align:start position:0% + +sort of one minus alpha from where i was + + align:start position:0% +sort of one minus alpha from where i was + + + align:start position:0% +sort of one minus alpha from where i was +centered around 1 minus alpha from where + + align:start position:0% +centered around 1 minus alpha from where + + + align:start position:0% +centered around 1 minus alpha from where +i was right + + align:start position:0% +i was right + + + align:start position:0% +i was right +now in the next step i have to consider + + align:start position:0% +now in the next step i have to consider + + + align:start position:0% +now in the next step i have to consider +the fact that i could be anywhere in + + align:start position:0% +the fact that i could be anywhere in + + + align:start position:0% +the fact that i could be anywhere in +that gaussian weighted appropriate + + align:start position:0% +that gaussian weighted appropriate + + + align:start position:0% +that gaussian weighted appropriate +appropriately and i have to consider all + + align:start position:0% +appropriately and i have to consider all + + + align:start position:0% +appropriately and i have to consider all +the updates from those that's what this + + align:start position:0% +the updates from those that's what this + + + align:start position:0% +the updates from those that's what this +integral is doing + + align:start position:0% +integral is doing + + + align:start position:0% +integral is doing +and it turns out the magic of gaussians + + align:start position:0% +and it turns out the magic of gaussians + + + align:start position:0% +and it turns out the magic of gaussians +and linearity is that + + align:start position:0% +and linearity is that + + + align:start position:0% +and linearity is that +if p of y is a gaussian + + align:start position:0% +if p of y is a gaussian + + + align:start position:0% +if p of y is a gaussian +and i multiply it by another gaussian + + align:start position:0% +and i multiply it by another gaussian + + + align:start position:0% +and i multiply it by another gaussian +and integrate + + align:start position:0% +and integrate + + + align:start position:0% +and integrate +i get out of gaussian now life is good + + align:start position:0% +i get out of gaussian now life is good + + + align:start position:0% +i get out of gaussian now life is good +um + + align:start position:0% +um + + + align:start position:0% +um +so i'll i'll leave the actual + + align:start position:0% +so i'll i'll leave the actual + + + align:start position:0% +so i'll i'll leave the actual +math to your yeah what the heck i'll + + align:start position:0% +math to your yeah what the heck i'll + + + align:start position:0% +math to your yeah what the heck i'll +just + + align:start position:0% + + + + align:start position:0% + +what you get + + align:start position:0% +what you get + + + align:start position:0% +what you get +i can write the the answer if you push a + + align:start position:0% +i can write the the answer if you push a + + + align:start position:0% +i can write the the answer if you push a +gaussian through + + align:start position:0% + + + + align:start position:0% + +turns out to be + + align:start position:0% +turns out to be + + + align:start position:0% +turns out to be +1 over + + align:start position:0% +1 over + + + align:start position:0% +1 over +square root of 2 pi + + align:start position:0% +square root of 2 pi + + + align:start position:0% +square root of 2 pi +sigma squared + + align:start position:0% +sigma squared + + + align:start position:0% +sigma squared +integral from negative infinity to + + align:start position:0% +integral from negative infinity to + + + align:start position:0% +integral from negative infinity to +infinity + + align:start position:0% +infinity + + + align:start position:0% +infinity +of e to the negative + + align:start position:0% +of e to the negative + + + align:start position:0% +of e to the negative +um + + align:start position:0% +um + + + align:start position:0% +um +let me actually write the + + align:start position:0% +let me actually write the + + + align:start position:0% +let me actually write the +skip that one line just to keep things + + align:start position:0% +skip that one line just to keep things + + + align:start position:0% +skip that one line just to keep things +moving + + align:start position:0% +moving + + + align:start position:0% +moving +um + + align:start position:0% +um + + + align:start position:0% +um +let's do one over one minus + + align:start position:0% +let's do one over one minus + + + align:start position:0% +let's do one over one minus +alpha + + align:start position:0% +alpha + + + align:start position:0% +alpha +square root of two pi c squared + + align:start position:0% + + + + align:start position:0% + +that's the probability of n + + align:start position:0% +that's the probability of n + + + align:start position:0% +that's the probability of n +at y prime one minus alpha + + align:start position:0% +at y prime one minus alpha + + + align:start position:0% +at y prime one minus alpha +d y alpha where y + + align:start position:0% +d y alpha where y + + + align:start position:0% +d y alpha where y +is + + align:start position:0% +is + + + align:start position:0% +is +one minus alpha y + + align:start position:0% +one minus alpha y + + + align:start position:0% +one minus alpha y +let's just + + align:start position:0% + + + + align:start position:0% + +haven't done a lot of work yet i just + + align:start position:0% +haven't done a lot of work yet i just + + + align:start position:0% +haven't done a lot of work yet i just +sort of changed coordinates into y prime + + align:start position:0% +sort of changed coordinates into y prime + + + align:start position:0% +sort of changed coordinates into y prime +and it turns out + + align:start position:0% +and it turns out + + + align:start position:0% +and it turns out +for instance if i look at for if i guess + + align:start position:0% +for instance if i look at for if i guess + + + align:start position:0% +for instance if i look at for if i guess +that the steady state is a gaussian form + + align:start position:0% +that the steady state is a gaussian form + + + align:start position:0% +that the steady state is a gaussian form +and i look for + + align:start position:0% +and i look for + + + align:start position:0% +and i look for +a place where this + + align:start position:0% +a place where this + + + align:start position:0% +a place where this +and this can possibly be the same + + align:start position:0% +and this can possibly be the same + + + align:start position:0% +and this can possibly be the same +function if i want to look at the steady + + align:start position:0% +function if i want to look at the steady + + + align:start position:0% +function if i want to look at the steady +state of this dynamics + + align:start position:0% + + + + align:start position:0% + +then i find that + + align:start position:0% +then i find that + + + align:start position:0% +then i find that +p star of x + + align:start position:0% + + + + align:start position:0% + +is one over + + align:start position:0% +is one over + + + align:start position:0% +is one over +um + + align:start position:0% +um + + + align:start position:0% +um +square root of two pi + + align:start position:0% +square root of two pi + + + align:start position:0% +square root of two pi +sigma zero + + align:start position:0% +sigma zero + + + align:start position:0% +sigma zero +squared + + align:start position:0% +squared + + + align:start position:0% +squared +e to the negative + + align:start position:0% +e to the negative + + + align:start position:0% +e to the negative +x + + align:start position:0% +x + + + align:start position:0% +x +squared + + align:start position:0% +squared + + + align:start position:0% +squared +over two sigma zero squared + + align:start position:0% + + + + align:start position:0% + +it's a gaussian it's actually a mean + + align:start position:0% +it's a gaussian it's actually a mean + + + align:start position:0% +it's a gaussian it's actually a mean +zero gaussian + + align:start position:0% +zero gaussian + + + align:start position:0% +zero gaussian +is the steady state of that update + + align:start position:0% +is the steady state of that update + + + align:start position:0% +is the steady state of that update +okay which is just a few lines in the + + align:start position:0% +okay which is just a few lines in the + + + align:start position:0% +okay which is just a few lines in the +notes + + align:start position:0% +notes + + + align:start position:0% +notes +where + + align:start position:0% +where + + + align:start position:0% +where +sigma zero + + align:start position:0% +sigma zero + + + align:start position:0% +sigma zero +squared is + + align:start position:0% +squared is + + + align:start position:0% +squared is +sigma squared which is the noise from + + align:start position:0% +sigma squared which is the noise from + + + align:start position:0% +sigma squared which is the noise from +the + + align:start position:0% +the + + + align:start position:0% +the +brownian motion + + align:start position:0% +brownian motion + + + align:start position:0% +brownian motion +minus alpha squared + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so i think actually this these equations + + align:start position:0% +so i think actually this these equations + + + align:start position:0% +so i think actually this these equations +tell the entire + + align:start position:0% +tell the entire + + + align:start position:0% +tell the entire +story + + align:start position:0% +story + + + align:start position:0% +story +um if i + + align:start position:0% +um if i + + + align:start position:0% +um if i +start my system even from a + + align:start position:0% +start my system even from a + + + align:start position:0% +start my system even from a +from some + + align:start position:0% +from some + + + align:start position:0% +from some +well specifically if i start my system + + align:start position:0% +well specifically if i start my system + + + align:start position:0% +well specifically if i start my system +in a delta function or in a gaussian + + align:start position:0% +in a delta function or in a gaussian + + + align:start position:0% +in a delta function or in a gaussian +distribution + + align:start position:0% +distribution + + + align:start position:0% +distribution +of initial conditions then i'm going to + + align:start position:0% +of initial conditions then i'm going to + + + align:start position:0% +of initial conditions then i'm going to +be gaussian for the rest of time turns + + align:start position:0% +be gaussian for the rest of time turns + + + align:start position:0% +be gaussian for the rest of time turns +out even if it's not it'll it'll go to a + + align:start position:0% +out even if it's not it'll it'll go to a + + + align:start position:0% +out even if it's not it'll it'll go to a +stable gaussian right + + align:start position:0% +stable gaussian right + + + align:start position:0% +stable gaussian right +and if i watch if i look far enough into + + align:start position:0% +and if i watch if i look far enough into + + + align:start position:0% +and if i watch if i look far enough into +the future at the steady state + + align:start position:0% +the future at the steady state + + + align:start position:0% +the future at the steady state +of that probability distribution + + align:start position:0% +of that probability distribution + + + align:start position:0% +of that probability distribution +then it's actually going to be what we + + align:start position:0% +then it's actually going to be what we + + + align:start position:0% +then it's actually going to be what we +hoped we'd find it's a mean zero + + align:start position:0% +hoped we'd find it's a mean zero + + + align:start position:0% +hoped we'd find it's a mean zero +gaussian this was zero in my plot + + align:start position:0% +gaussian this was zero in my plot + + + align:start position:0% +gaussian this was zero in my plot +and its width its variance is given by + + align:start position:0% +and its width its variance is given by + + + align:start position:0% +and its width its variance is given by +two competing terms right + + align:start position:0% +two competing terms right + + + align:start position:0% +two competing terms right +you've got the noise + + align:start position:0% +you've got the noise + + + align:start position:0% +you've got the noise +from the brownian motion trying to push + + align:start position:0% +from the brownian motion trying to push + + + align:start position:0% +from the brownian motion trying to push +you out into larger variants + + align:start position:0% +you out into larger variants + + + align:start position:0% +you out into larger variants +and you've got the competing force of + + align:start position:0% +and you've got the competing force of + + + align:start position:0% +and you've got the competing force of +the + + align:start position:0% +the + + + align:start position:0% +the +stability of the dynamics pushing you + + align:start position:0% +stability of the dynamics pushing you + + + align:start position:0% +stability of the dynamics pushing you +back in + + align:start position:0% +back in + + + align:start position:0% +back in +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so if alpha gets and you actually this + + align:start position:0% +so if alpha gets and you actually this + + + align:start position:0% +so if alpha gets and you actually this +also + + align:start position:0% +also + + + align:start position:0% +also +is valid exactly when alpha is + + align:start position:0% +is valid exactly when alpha is + + + align:start position:0% +is valid exactly when alpha is +between zero and two it doesn't go to + + align:start position:0% +between zero and two it doesn't go to + + + align:start position:0% +between zero and two it doesn't go to +zero in that regime yeah + + align:start position:0% +zero in that regime yeah + + + align:start position:0% +zero in that regime yeah +okay + + align:start position:0% + + + + align:start position:0% + +so if i want to look at that particle + + align:start position:0% +so if i want to look at that particle + + + align:start position:0% +so if i want to look at that particle +at time 100 or time 10 000 + + align:start position:0% +at time 100 or time 10 000 + + + align:start position:0% +at time 100 or time 10 000 +then i should expect to see it + + align:start position:0% +then i should expect to see it + + + align:start position:0% +then i should expect to see it +somewhere with with probability given by + + align:start position:0% +somewhere with with probability given by + + + align:start position:0% +somewhere with with probability given by +this distribution + + align:start position:0% +this distribution + + + align:start position:0% +this distribution +um + + align:start position:0% +um + + + align:start position:0% +um +you know in the vicinity of that zero + + align:start position:0% +you know in the vicinity of that zero + + + align:start position:0% +you know in the vicinity of that zero +okay and that comes out of simple math + + align:start position:0% +okay and that comes out of simple math + + + align:start position:0% +okay and that comes out of simple math +of pushing + + align:start position:0% +of pushing + + + align:start position:0% +of pushing +this + + align:start position:0% +this + + + align:start position:0% +this +gaussian + + align:start position:0% +gaussian + + + align:start position:0% +gaussian +through this equation okay + + align:start position:0% + + + + align:start position:0% + +now you all probably unless you probably + + align:start position:0% +now you all probably unless you probably + + + align:start position:0% +now you all probably unless you probably +knew that before + + align:start position:0% +knew that before + + + align:start position:0% +knew that before +why do you know this before + + align:start position:0% +why do you know this before + + + align:start position:0% +why do you know this before +maybe not in this in this level of + + align:start position:0% +maybe not in this in this level of + + + align:start position:0% +maybe not in this in this level of +detail but + + align:start position:0% +detail but + + + align:start position:0% +detail but +why do many of you know this already + + align:start position:0% +why do many of you know this already + + + align:start position:0% +why do many of you know this already +it's a common filter right + + align:start position:0% +it's a common filter right + + + align:start position:0% +it's a common filter right +the common filtered forward + + align:start position:0% +the common filtered forward + + + align:start position:0% +the common filtered forward +process takes a gaussian shoves it + + align:start position:0% +process takes a gaussian shoves it + + + align:start position:0% +process takes a gaussian shoves it +through a linear system stays gaussian + + align:start position:0% +through a linear system stays gaussian + + + align:start position:0% +through a linear system stays gaussian +this is the single + + align:start position:0% +this is the single + + + align:start position:0% +this is the single +variable + + align:start position:0% +variable + + + align:start position:0% +variable +a little more careful version maybe than + + align:start position:0% +a little more careful version maybe than + + + align:start position:0% +a little more careful version maybe than +you than you you do if you call matlab's + + align:start position:0% +you than you you do if you call matlab's + + + align:start position:0% +you than you you do if you call matlab's +common stuff + + align:start position:0% +common stuff + + + align:start position:0% +common stuff +but + + align:start position:0% +but + + + align:start position:0% +but +yeah so that's that's not a surprising + + align:start position:0% +yeah so that's that's not a surprising + + + align:start position:0% +yeah so that's that's not a surprising +result but i think it forces you to + + align:start position:0% +result but i think it forces you to + + + align:start position:0% +result but i think it forces you to +think about a couple things right so + + align:start position:0% +think about a couple things right so + + + align:start position:0% +think about a couple things right so +um + + align:start position:0% + + + + align:start position:0% + +like i said the stability of the system + + align:start position:0% + + + + align:start position:0% + +is critical in determining that final + + align:start position:0% +is critical in determining that final + + + align:start position:0% +is critical in determining that final +uh that final distribution + + align:start position:0% +uh that final distribution + + + align:start position:0% +uh that final distribution +but even more significantly than that + + align:start position:0% +but even more significantly than that + + + align:start position:0% +but even more significantly than that +there's some implications right of + + align:start position:0% +there's some implications right of + + + align:start position:0% +there's some implications right of +having these noise noise in the system + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +implications of having stochastic + + align:start position:0% +implications of having stochastic + + + align:start position:0% +implications of having stochastic +dynamics okay + + align:start position:0% + + + + align:start position:0% + +if you want to reason about + + align:start position:0% +if you want to reason about + + + align:start position:0% +if you want to reason about +the cost that you're going to incur + + align:start position:0% +the cost that you're going to incur + + + align:start position:0% +the cost that you're going to incur +given some policy + + align:start position:0% +given some policy + + + align:start position:0% +given some policy +for instance + + align:start position:0% +for instance + + + align:start position:0% +for instance +in order to reason about the future + + align:start position:0% +in order to reason about the future + + + align:start position:0% +in order to reason about the future +dynamics + + align:start position:0% + + + + align:start position:0% + +even though you know the current state + + align:start position:0% +even though you know the current state + + + align:start position:0% +even though you know the current state +you know so even given initial + + align:start position:0% +you know so even given initial + + + align:start position:0% +you know so even given initial +conditions + + align:start position:0% + + + + align:start position:0% + +you have to reason about + + align:start position:0% +you have to reason about + + + align:start position:0% +you have to reason about +it's not enough to just reason about x + + align:start position:0% +it's not enough to just reason about x + + + align:start position:0% +it's not enough to just reason about x +you have to reason about + + align:start position:0% + + + + align:start position:0% + +that entire distribution p + + align:start position:0% +that entire distribution p + + + align:start position:0% +that entire distribution p +what i call p n of x + + align:start position:0% + + + + align:start position:0% + +right + + align:start position:0% +right + + + align:start position:0% +right +not just x + + align:start position:0% + + + + align:start position:0% + +okay so as soon as we start doing + + align:start position:0% +okay so as soon as we start doing + + + align:start position:0% +okay so as soon as we start doing +stochastic stuff we have to change + + align:start position:0% +stochastic stuff we have to change + + + align:start position:0% +stochastic stuff we have to change +our view of the world the state x is not + + align:start position:0% +our view of the world the state x is not + + + align:start position:0% +our view of the world the state x is not +the only thing you care about moving + + align:start position:0% +the only thing you care about moving + + + align:start position:0% +the only thing you care about moving +forward you care about the probability + + align:start position:0% +forward you care about the probability + + + align:start position:0% +forward you care about the probability +distribution of states that you live in + + align:start position:0% + + + + align:start position:0% + +what would you say about the stability + + align:start position:0% +what would you say about the stability + + + align:start position:0% +what would you say about the stability +of this system + + align:start position:0% + + + + align:start position:0% + +if i asked you is that a stable system + + align:start position:0% +if i asked you is that a stable system + + + align:start position:0% +if i asked you is that a stable system +what would you + + align:start position:0% + + + + align:start position:0% + +say i'm asking and we're we're going to + + align:start position:0% +say i'm asking and we're we're going to + + + align:start position:0% +say i'm asking and we're we're going to +do that but i'm asking you for your + + align:start position:0% +do that but i'm asking you for your + + + align:start position:0% +do that but i'm asking you for your +intuition what would you guess would + + align:start position:0% +intuition what would you guess would + + + align:start position:0% +intuition what would you guess would +would you feel comfortable if i said + + align:start position:0% +would you feel comfortable if i said + + + align:start position:0% +would you feel comfortable if i said +it's a stable system let's move on + + align:start position:0% + + + + align:start position:0% + +in some ways it's okay because + + align:start position:0% +in some ways it's okay because + + + align:start position:0% +in some ways it's okay because +the distribution is stable + + align:start position:0% +the distribution is stable + + + align:start position:0% +the distribution is stable +x + + align:start position:0% +x + + + align:start position:0% +x +is not stable + + align:start position:0% +is not stable + + + align:start position:0% +is not stable +okay + + align:start position:0% + + + + align:start position:0% + +if i look at if i'm at there's no fixed + + align:start position:0% +if i look at if i'm at there's no fixed + + + align:start position:0% +if i look at if i'm at there's no fixed +point in x right the noise is going to + + align:start position:0% +point in x right the noise is going to + + + align:start position:0% +point in x right the noise is going to +keep moving me around okay + + align:start position:0% +keep moving me around okay + + + align:start position:0% +keep moving me around okay +but + + align:start position:0% +but + + + align:start position:0% +but +i told you that p of x actually well i + + align:start position:0% +i told you that p of x actually well i + + + align:start position:0% +i told you that p of x actually well i +only told you it's a fixed point but i + + align:start position:0% +only told you it's a fixed point but i + + + align:start position:0% +only told you it's a fixed point but i +can tell you it's a stable fixed point + + align:start position:0% +can tell you it's a stable fixed point + + + align:start position:0% +can tell you it's a stable fixed point +p of x is actually stable okay + + align:start position:0% + + + + align:start position:0% + +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +this + + align:start position:0% +this + + + align:start position:0% +this +basically this equation right here this + + align:start position:0% +basically this equation right here this + + + align:start position:0% +basically this equation right here this +this update right here + + align:start position:0% +this update right here + + + align:start position:0% +this update right here +it's a very famous important thing + + align:start position:0% +it's a very famous important thing + + + align:start position:0% +it's a very famous important thing +well + + align:start position:0% +well + + + align:start position:0% +well +so important that it's called the master + + align:start position:0% +so important that it's called the master + + + align:start position:0% +so important that it's called the master +equation yeah + + align:start position:0% + + + + align:start position:0% + +i mean don't just name it after some guy + + align:start position:0% +i mean don't just name it after some guy + + + align:start position:0% +i mean don't just name it after some guy +call it the master equation + + align:start position:0% + + + + align:start position:0% + +and there are various versions of the + + align:start position:0% +and there are various versions of the + + + align:start position:0% +and there are various versions of the +master equation on specific problems + + align:start position:0% +master equation on specific problems + + + align:start position:0% +master equation on specific problems +that are + + align:start position:0% +that are + + + align:start position:0% +that are +named after people's last names but + + align:start position:0% +named after people's last names but + + + align:start position:0% +named after people's last names but +but in general it's the master equation + + align:start position:0% +but in general it's the master equation + + + align:start position:0% +but in general it's the master equation +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so you can't forget how significant it + + align:start position:0% +so you can't forget how significant it + + + align:start position:0% +so you can't forget how significant it +is + + align:start position:0% +is + + + align:start position:0% +is +and the idea is that the the in the + + align:start position:0% +and the idea is that the the in the + + + align:start position:0% +and the idea is that the the in the +master equation + + align:start position:0% +master equation + + + align:start position:0% +master equation +you're looking at the dynamics of the + + align:start position:0% +you're looking at the dynamics of the + + + align:start position:0% +you're looking at the dynamics of the +probability distribution not the + + align:start position:0% +probability distribution not the + + + align:start position:0% +probability distribution not the +dynamics of a single state the dynamics + + align:start position:0% +dynamics of a single state the dynamics + + + align:start position:0% +dynamics of a single state the dynamics +of a probability distribution okay so + + align:start position:0% +of a probability distribution okay so + + + align:start position:0% +of a probability distribution okay so +that probability distribution actually + + align:start position:0% +that probability distribution actually + + + align:start position:0% +that probability distribution actually +in the master equation is stable + + align:start position:0% +in the master equation is stable + + + align:start position:0% +in the master equation is stable +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now there are more complicated cases + + align:start position:0% +now there are more complicated cases + + + align:start position:0% +now there are more complicated cases +actually right + + align:start position:0% +actually right + + + align:start position:0% +actually right +so + + align:start position:0% +so + + + align:start position:0% +so +um + + align:start position:0% + + + + align:start position:0% + +what about this one + + align:start position:0% + + + + align:start position:0% + +what's this thing going to do in the + + align:start position:0% +what's this thing going to do in the + + + align:start position:0% +what's this thing going to do in the +long run + + align:start position:0% + + + + align:start position:0% + +it's going to have a bimodal + + align:start position:0% +it's going to have a bimodal + + + align:start position:0% +it's going to have a bimodal +distribution in the long run + + align:start position:0% +distribution in the long run + + + align:start position:0% +distribution in the long run +right so + + align:start position:0% +right so + + + align:start position:0% +right so +it would be + + align:start position:0% +it would be + + + align:start position:0% +it would be +sort of + + align:start position:0% +sort of + + + align:start position:0% +sort of +inappropriate to say either those points + + align:start position:0% +inappropriate to say either those points + + + align:start position:0% +inappropriate to say either those points +i mean they they that are that either of + + align:start position:0% +i mean they they that are that either of + + + align:start position:0% +i mean they they that are that either of +those points are fixed points for the + + align:start position:0% +those points are fixed points for the + + + align:start position:0% +those points are fixed points for the +deterministic case they are for the + + align:start position:0% +deterministic case they are for the + + + align:start position:0% +deterministic case they are for the +stochastic case they're not and you're + + align:start position:0% +stochastic case they're not and you're + + + align:start position:0% +stochastic case they're not and you're +right it's going to go to some + + align:start position:0% +right it's going to go to some + + + align:start position:0% +right it's going to go to some +distribution + + align:start position:0% +distribution + + + align:start position:0% +distribution +like this okay + + align:start position:0% + + + + align:start position:0% + +i have a decision point which of my 10 + + align:start position:0% +i have a decision point which of my 10 + + + align:start position:0% +i have a decision point which of my 10 +pages i should do + + align:start position:0% +pages i should do + + + align:start position:0% +pages i should do +i could talk about um + + align:start position:0% +i could talk about um + + + align:start position:0% +i could talk about um +you know some examples of just + + align:start position:0% +you know some examples of just + + + align:start position:0% +you know some examples of just +stochastic dynamics for instance and + + align:start position:0% +stochastic dynamics for instance and + + + align:start position:0% +stochastic dynamics for instance and +walking robots + + align:start position:0% +walking robots + + + align:start position:0% +walking robots +or i could get to the + + align:start position:0% +or i could get to the + + + align:start position:0% +or i could get to the +optimal control of these of the more + + align:start position:0% +optimal control of these of the more + + + align:start position:0% +optimal control of these of the more +simple system + + align:start position:0% + + + + align:start position:0% + +i have to set john up for next week so + + align:start position:0% +i have to set john up for next week so + + + align:start position:0% +i have to set john up for next week so +so i guess i gotta + + align:start position:0% + + + + align:start position:0% + +just tell you that that actually we've + + align:start position:0% +just tell you that that actually we've + + + align:start position:0% +just tell you that that actually we've +done some work + + align:start position:0% +done some work + + + align:start position:0% +done some work +thinking about uh for instance like the + + align:start position:0% +thinking about uh for instance like the + + + align:start position:0% +thinking about uh for instance like the +rimless wheel i'll just tell you the the + + align:start position:0% +rimless wheel i'll just tell you the the + + + align:start position:0% +rimless wheel i'll just tell you the the +setup and i won't tell you all the + + align:start position:0% +setup and i won't tell you all the + + + align:start position:0% +setup and i won't tell you all the +details + + align:start position:0% +details + + + align:start position:0% +details +so so here's a realistic example of that + + align:start position:0% +so so here's a realistic example of that + + + align:start position:0% +so so here's a realistic example of that +of that + + align:start position:0% + + + + align:start position:0% + +sort of dynamics take your rimless wheel + + align:start position:0% +sort of dynamics take your rimless wheel + + + align:start position:0% +sort of dynamics take your rimless wheel +okay + + align:start position:0% +okay + + + align:start position:0% +okay +dynamics and let's say + + align:start position:0% +dynamics and let's say + + + align:start position:0% +dynamics and let's say +um + + align:start position:0% +um + + + align:start position:0% +um +instead of walking down some + + align:start position:0% +instead of walking down some + + + align:start position:0% +instead of walking down some +some constant ramp let's say on every + + align:start position:0% +some constant ramp let's say on every + + + align:start position:0% +some constant ramp let's say on every +step the ramp angle is drawn from some + + align:start position:0% +step the ramp angle is drawn from some + + + align:start position:0% +step the ramp angle is drawn from some +distribution okay so this is passive + + align:start position:0% +distribution okay so this is passive + + + align:start position:0% +distribution okay so this is passive +walking on rough terrain + + align:start position:0% +walking on rough terrain + + + align:start position:0% +walking on rough terrain +and it turns out it's not it's not + + align:start position:0% +and it turns out it's not it's not + + + align:start position:0% +and it turns out it's not it's not +following a limit cycle anymore right + + align:start position:0% +following a limit cycle anymore right + + + align:start position:0% +following a limit cycle anymore right +but it's always it's it's long-term + + align:start position:0% +but it's always it's it's long-term + + + align:start position:0% +but it's always it's it's long-term +probability distribution + + align:start position:0% +probability distribution + + + align:start position:0% +probability distribution +is well there's there's a there's a + + align:start position:0% +is well there's there's a there's a + + + align:start position:0% +is well there's there's a there's a +slightly more complicated story + + align:start position:0% +slightly more complicated story + + + align:start position:0% +slightly more complicated story +if i look long enough + + align:start position:0% +if i look long enough + + + align:start position:0% +if i look long enough +this thing has an absorbing state right + + align:start position:0% +this thing has an absorbing state right + + + align:start position:0% +this thing has an absorbing state right +so if i if i take a big enough step + + align:start position:0% +so if i if i take a big enough step + + + align:start position:0% +so if i if i take a big enough step +then eventually i'm going to lose enough + + align:start position:0% +then eventually i'm going to lose enough + + + align:start position:0% +then eventually i'm going to lose enough +energy remember the deterministic system + + align:start position:0% +energy remember the deterministic system + + + align:start position:0% +energy remember the deterministic system +had two + + align:start position:0% +had two + + + align:start position:0% +had two +fixed points one was standing still the + + align:start position:0% +fixed points one was standing still the + + + align:start position:0% +fixed points one was standing still the +other one was rolling at a constant + + align:start position:0% +other one was rolling at a constant + + + align:start position:0% +other one was rolling at a constant +speed okay + + align:start position:0% +speed okay + + + align:start position:0% +speed okay +the standing still fixed point on rough + + align:start position:0% +the standing still fixed point on rough + + + align:start position:0% +the standing still fixed point on rough +terrain is an absorbing fixed point if i + + align:start position:0% +terrain is an absorbing fixed point if i + + + align:start position:0% +terrain is an absorbing fixed point if i +get there and i never take another + + align:start position:0% +get there and i never take another + + + align:start position:0% +get there and i never take another +another step that i'm never going to + + align:start position:0% +another step that i'm never going to + + + align:start position:0% +another step that i'm never going to +leave that fixed point so that is + + align:start position:0% +leave that fixed point so that is + + + align:start position:0% +leave that fixed point so that is +actually a true fixed point yeah + + align:start position:0% +actually a true fixed point yeah + + + align:start position:0% +actually a true fixed point yeah +the rolling fixed point you're going to + + align:start position:0% +the rolling fixed point you're going to + + + align:start position:0% +the rolling fixed point you're going to +tend to bounce around that fixed point + + align:start position:0% +tend to bounce around that fixed point + + + align:start position:0% +tend to bounce around that fixed point +so maybe this picture is something more + + align:start position:0% +so maybe this picture is something more + + + align:start position:0% +so maybe this picture is something more +like + + align:start position:0% +like + + + align:start position:0% +like +this + + align:start position:0% +this + + + align:start position:0% +this +yeah okay + + align:start position:0% +yeah okay + + + align:start position:0% +yeah okay +so + + align:start position:0% +so + + + align:start position:0% +so +the standing still fixed point if i get + + align:start position:0% +the standing still fixed point if i get + + + align:start position:0% +the standing still fixed point if i get +in there it's absorbing + + align:start position:0% +in there it's absorbing + + + align:start position:0% +in there it's absorbing +you know i'm never coming out + + align:start position:0% +you know i'm never coming out + + + align:start position:0% +you know i'm never coming out +but the rolling fix point you tend to be + + align:start position:0% +but the rolling fix point you tend to be + + + align:start position:0% +but the rolling fix point you tend to be +bounce around this limit cycle okay and + + align:start position:0% +bounce around this limit cycle okay and + + + align:start position:0% +bounce around this limit cycle okay and +then every once in a while in the + + align:start position:0% +then every once in a while in the + + + align:start position:0% +then every once in a while in the +stochastic + + align:start position:0% +stochastic + + + align:start position:0% +stochastic +dynamics case they say that these + + align:start position:0% +dynamics case they say that these + + + align:start position:0% +dynamics case they say that these +particles make an escape attempt so they + + align:start position:0% +particles make an escape attempt so they + + + align:start position:0% +particles make an escape attempt so they +call it right + + align:start position:0% + + + + align:start position:0% + +okay and maybe + + align:start position:0% +okay and maybe + + + align:start position:0% +okay and maybe +shoot over and fall down + + align:start position:0% +shoot over and fall down + + + align:start position:0% +shoot over and fall down +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and it's really very beautiful if you + + align:start position:0% +and it's really very beautiful if you + + + align:start position:0% +and it's really very beautiful if you +watch the probability distributions as + + align:start position:0% +watch the probability distributions as + + + align:start position:0% +watch the probability distributions as +they propagate through the roomless + + align:start position:0% +they propagate through the roomless + + + align:start position:0% +they propagate through the roomless +wheel equations or the composite + + align:start position:0% +wheel equations or the composite + + + align:start position:0% +wheel equations or the composite +equations or you name it then + + align:start position:0% +equations or you name it then + + + align:start position:0% +equations or you name it then +what you get is you get this + + align:start position:0% +what you get is you get this + + + align:start position:0% +what you get is you get this +probability mass around here right for a + + align:start position:0% +probability mass around here right for a + + + align:start position:0% +probability mass around here right for a +long time it's pretty likely that i'm in + + align:start position:0% +long time it's pretty likely that i'm in + + + align:start position:0% +long time it's pretty likely that i'm in +this in the vicinity of that limit cycle + + align:start position:0% +this in the vicinity of that limit cycle + + + align:start position:0% +this in the vicinity of that limit cycle +right and then slowly as the time goes + + align:start position:0% +right and then slowly as the time goes + + + align:start position:0% +right and then slowly as the time goes +on the escape attempts continue to the + + align:start position:0% +on the escape attempts continue to the + + + align:start position:0% +on the escape attempts continue to the +point where this thing gets smaller and + + align:start position:0% +point where this thing gets smaller and + + + align:start position:0% +point where this thing gets smaller and +smaller until as time goes to infinity + + align:start position:0% +smaller until as time goes to infinity + + + align:start position:0% +smaller until as time goes to infinity +i'm only going to be standing still + + align:start position:0% +i'm only going to be standing still + + + align:start position:0% +i'm only going to be standing still +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so the + + align:start position:0% + + + + align:start position:0% + +sort of negative pessimistic view of + + align:start position:0% +sort of negative pessimistic view of + + + align:start position:0% +sort of negative pessimistic view of +that work is to say that um + + align:start position:0% +that work is to say that um + + + align:start position:0% +that work is to say that um +you're always going to fall down you + + align:start position:0% +you're always going to fall down you + + + align:start position:0% +you're always going to fall down you +build the best robot you want but if you + + align:start position:0% +build the best robot you want but if you + + + align:start position:0% +build the best robot you want but if you +have a reasonable model of the dynamics + + align:start position:0% +have a reasonable model of the dynamics + + + align:start position:0% +have a reasonable model of the dynamics +it's always going to fall down right if + + align:start position:0% +it's always going to fall down right if + + + align:start position:0% +it's always going to fall down right if +you wait long enough + + align:start position:0% +you wait long enough + + + align:start position:0% +you wait long enough +you know + + align:start position:0% +you know + + + align:start position:0% +you know +a mac truck is going to come along and + + align:start position:0% +a mac truck is going to come along and + + + align:start position:0% +a mac truck is going to come along and +hit it or or + + align:start position:0% +hit it or or + + + align:start position:0% +hit it or or +you know it's going to walk into a door + + align:start position:0% +you know it's going to walk into a door + + + align:start position:0% +you know it's going to walk into a door +or something like that you know you can + + align:start position:0% +or something like that you know you can + + + align:start position:0% +or something like that you know you can +do the best you want but it's going to + + align:start position:0% +do the best you want but it's going to + + + align:start position:0% +do the best you want but it's going to +fall down and that's it'll end up on + + align:start position:0% +fall down and that's it'll end up on + + + align:start position:0% +fall down and that's it'll end up on +youtube probably right + + align:start position:0% +youtube probably right + + + align:start position:0% +youtube probably right +so + + align:start position:0% +so + + + align:start position:0% +so +you're assuming your + + align:start position:0% +you're assuming your + + + align:start position:0% +you're assuming your +ramp distribution is actually gaussian + + align:start position:0% +ramp distribution is actually gaussian + + + align:start position:0% +ramp distribution is actually gaussian +that's what we decided yep + + align:start position:0% +that's what we decided yep + + + align:start position:0% +that's what we decided yep +but that doesn't actually imply that the + + align:start position:0% +but that doesn't actually imply that the + + + align:start position:0% +but that doesn't actually imply that the +um the posterior is gaussian because + + align:start position:0% +um the posterior is gaussian because + + + align:start position:0% +um the posterior is gaussian because +it's going through non-linear dynamics + + align:start position:0% +it's going through non-linear dynamics + + + align:start position:0% +it's going through non-linear dynamics +right but i mean in reality the random + + align:start position:0% +right but i mean in reality the random + + + align:start position:0% +right but i mean in reality the random +distribution is never going to be truly + + align:start position:0% +distribution is never going to be truly + + + align:start position:0% +distribution is never going to be truly +gaussian right because + + align:start position:0% +gaussian right because + + + align:start position:0% +gaussian right because +everything's gaussian if you uh if you + + align:start position:0% +everything's gaussian if you uh if you + + + align:start position:0% +everything's gaussian if you uh if you +get enough of i don't know i mean i + + align:start position:0% +get enough of i don't know i mean i + + + align:start position:0% +get enough of i don't know i mean i +think that's + + align:start position:0% +think that's + + + align:start position:0% +think that's +do you want to do stairs or something + + align:start position:0% +do you want to do stairs or something + + + align:start position:0% +do you want to do stairs or something +more specific + + align:start position:0% +more specific + + + align:start position:0% +more specific +oh well i'm just saying if if there is a + + align:start position:0% +oh well i'm just saying if if there is a + + + align:start position:0% +oh well i'm just saying if if there is a +hard limit on + + align:start position:0% +hard limit on + + + align:start position:0% +hard limit on +how steep your brand is oh you could + + align:start position:0% +how steep your brand is oh you could + + + align:start position:0% +how steep your brand is oh you could +guarantee that good very good point + + align:start position:0% +guarantee that good very good point + + + align:start position:0% +guarantee that good very good point +right so so if + + align:start position:0% +right so so if + + + align:start position:0% +right so so if +if the distributions don't didn't have + + align:start position:0% +if the distributions don't didn't have + + + align:start position:0% +if the distributions don't didn't have +tails then there are cases where i can + + align:start position:0% +tails then there are cases where i can + + + align:start position:0% +tails then there are cases where i can +bound + + align:start position:0% +bound + + + align:start position:0% +bound +um it never going over but those tails + + align:start position:0% +um it never going over but those tails + + + align:start position:0% +um it never going over but those tails +actually have to be pretty steep the the + + align:start position:0% +actually have to be pretty steep the the + + + align:start position:0% +actually have to be pretty steep the the +limitations have to be pretty steep + + align:start position:0% +limitations have to be pretty steep + + + align:start position:0% +limitations have to be pretty steep +because you not you have to make sure + + align:start position:0% +because you not you have to make sure + + + align:start position:0% +because you not you have to make sure +that on a single step the damping + + align:start position:0% +that on a single step the damping + + + align:start position:0% +that on a single step the damping +overcomes the the biggest possible + + align:start position:0% +overcomes the the biggest possible + + + align:start position:0% +overcomes the the biggest possible +perturbation + + align:start position:0% +perturbation + + + align:start position:0% +perturbation +if on a single if your noise can ever be + + align:start position:0% +if on a single if your noise can ever be + + + align:start position:0% +if on a single if your noise can ever be +bigger than what you can take out in a + + align:start position:0% +bigger than what you can take out in a + + + align:start position:0% +bigger than what you can take out in a +single step then you will eventually as + + align:start position:0% +single step then you will eventually as + + + align:start position:0% +single step then you will eventually as +time goes to infinity find a way to get + + align:start position:0% +time goes to infinity find a way to get + + + align:start position:0% +time goes to infinity find a way to get +out + + align:start position:0% +out + + + align:start position:0% +out +yeah + + align:start position:0% + + + + align:start position:0% + +so katie + + align:start position:0% +so katie + + + align:start position:0% +so katie +bill did some nice work uh and and sort + + align:start position:0% +bill did some nice work uh and and sort + + + align:start position:0% +bill did some nice work uh and and sort +of quantifying the metastable dynamics + + align:start position:0% +of quantifying the metastable dynamics + + + align:start position:0% +of quantifying the metastable dynamics +of walking and actually i think that so + + align:start position:0% +of walking and actually i think that so + + + align:start position:0% +of walking and actually i think that so +it's called what we call the metastable + + align:start position:0% +it's called what we call the metastable + + + align:start position:0% +it's called what we call the metastable +because that distribution is is um + + align:start position:0% +because that distribution is is um + + + align:start position:0% +because that distribution is is um +long living it still makes sense to talk + + align:start position:0% +long living it still makes sense to talk + + + align:start position:0% +long living it still makes sense to talk +about where you'd expect this thing to + + align:start position:0% +about where you'd expect this thing to + + + align:start position:0% +about where you'd expect this thing to +be while it's walking but eventually we + + align:start position:0% +be while it's walking but eventually we + + + align:start position:0% +be while it's walking but eventually we +have to admit it's going to be it's + + align:start position:0% +have to admit it's going to be it's + + + align:start position:0% +have to admit it's going to be it's +going to go to + + align:start position:0% +going to go to + + + align:start position:0% +going to go to +falling down like a diamond + + align:start position:0% +falling down like a diamond + + + align:start position:0% +falling down like a diamond +is a diamond for a very long time but + + align:start position:0% +is a diamond for a very long time but + + + align:start position:0% +is a diamond for a very long time but +eventually it'll turn back into graphite + + align:start position:0% +eventually it'll turn back into graphite + + + align:start position:0% +eventually it'll turn back into graphite +okay so um + + align:start position:0% + + + + align:start position:0% + +good so there's actually beautiful even + + align:start position:0% +good so there's actually beautiful even + + + align:start position:0% +good so there's actually beautiful even +if you don't care about control i think + + align:start position:0% +if you don't care about control i think + + + align:start position:0% +if you don't care about control i think +there's actually beautiful things that + + align:start position:0% +there's actually beautiful things that + + + align:start position:0% +there's actually beautiful things that +happen in stochastic dynamics but the + + align:start position:0% +happen in stochastic dynamics but the + + + align:start position:0% +happen in stochastic dynamics but the +thing that that matters here is we've + + align:start position:0% +thing that that matters here is we've + + + align:start position:0% +thing that that matters here is we've +switched hats we've now started thinking + + align:start position:0% +switched hats we've now started thinking + + + align:start position:0% +switched hats we've now started thinking +about probability distributions and how + + align:start position:0% +about probability distributions and how + + + align:start position:0% +about probability distributions and how +they evolve with dynamics and how we can + + align:start position:0% +they evolve with dynamics and how we can + + + align:start position:0% +they evolve with dynamics and how we can +change those probability distributions + + align:start position:0% +change those probability distributions + + + align:start position:0% +change those probability distributions +with control + + align:start position:0% +with control + + + align:start position:0% +with control +right + + align:start position:0% +right + + + align:start position:0% +right +if i could if i could control the shape + + align:start position:0% +if i could if i could control the shape + + + align:start position:0% +if i could if i could control the shape +of that right then i can control those + + align:start position:0% +of that right then i can control those + + + align:start position:0% +of that right then i can control those +probability distributions for instance + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so + + align:start position:0% +so + + + align:start position:0% +so +it turns out + + align:start position:0% + + + + align:start position:0% + +it's sort of + + align:start position:0% +it's sort of + + + align:start position:0% +it's sort of +trivial to work + + align:start position:0% +trivial to work + + + align:start position:0% +trivial to work +stochastic to solve stochastic optimal + + align:start position:0% +stochastic to solve stochastic optimal + + + align:start position:0% +stochastic to solve stochastic optimal +control problems + + align:start position:0% +control problems + + + align:start position:0% +control problems +um + + align:start position:0% +um + + + align:start position:0% +um +at least with with dynamic programming + + align:start position:0% +at least with with dynamic programming + + + align:start position:0% +at least with with dynamic programming +okay + + align:start position:0% + + + + align:start position:0% + +it works out because of this additive + + align:start position:0% +it works out because of this additive + + + align:start position:0% +it works out because of this additive +cost + + align:start position:0% +cost + + + align:start position:0% +cost +structure + + align:start position:0% +structure + + + align:start position:0% +structure +that it's sort of no more expensive + + align:start position:0% + + + + align:start position:0% + +roughly no more expensive to solve the + + align:start position:0% +roughly no more expensive to solve the + + + align:start position:0% +roughly no more expensive to solve the +stochastic optimal control + + align:start position:0% + + + + align:start position:0% + +so the deterministic one + + align:start position:0% + + + + align:start position:0% + +and it matters i i maybe i should even + + align:start position:0% +and it matters i i maybe i should even + + + align:start position:0% +and it matters i i maybe i should even +make the point that it matters okay so + + align:start position:0% +make the point that it matters okay so + + + align:start position:0% +make the point that it matters okay so +so if i have a stochastic process + + align:start position:0% +so if i have a stochastic process + + + align:start position:0% +so if i have a stochastic process +and in general + + align:start position:0% +and in general + + + align:start position:0% +and in general +the optimal policy that you get from + + align:start position:0% +the optimal policy that you get from + + + align:start position:0% +the optimal policy that you get from +stochastic + + align:start position:0% +stochastic + + + align:start position:0% +stochastic +optimal control is going to be different + + align:start position:0% +optimal control is going to be different + + + align:start position:0% +optimal control is going to be different +than the one you get + + align:start position:0% +than the one you get + + + align:start position:0% +than the one you get +from deterministic optimal control + + align:start position:0% +from deterministic optimal control + + + align:start position:0% +from deterministic optimal control +so + + align:start position:0% +so + + + align:start position:0% +so +so potentially in dramatic ways + + align:start position:0% +so potentially in dramatic ways + + + align:start position:0% +so potentially in dramatic ways +right let me let me try to make that + + align:start position:0% +right let me let me try to make that + + + align:start position:0% +right let me let me try to make that +that point here so imagine i've got my + + align:start position:0% +that point here so imagine i've got my + + + align:start position:0% +that point here so imagine i've got my +um + + align:start position:0% + + + + align:start position:0% + +i've got a trash can robot i shouldn't + + align:start position:0% +i've got a trash can robot i shouldn't + + + align:start position:0% +i've got a trash can robot i shouldn't +call them check i got i've got a um + + align:start position:0% +call them check i got i've got a um + + + align:start position:0% +call them check i got i've got a um +you know what are they the + + align:start position:0% +you know what are they the + + + align:start position:0% +you know what are they the +uh what are the names of those little + + align:start position:0% +uh what are the names of those little + + + align:start position:0% +uh what are the names of those little +red robots pioneer robot or something + + align:start position:0% +red robots pioneer robot or something + + + align:start position:0% +red robots pioneer robot or something +like this yeah and uh um + + align:start position:0% +like this yeah and uh um + + + align:start position:0% +like this yeah and uh um +i want to get it from + + align:start position:0% +i want to get it from + + + align:start position:0% +i want to get it from +you know to this goal + + align:start position:0% +you know to this goal + + + align:start position:0% +you know to this goal +let's say i've got a cost function like + + align:start position:0% +let's say i've got a cost function like + + + align:start position:0% +let's say i've got a cost function like +this and i start over here and as i go i + + align:start position:0% +this and i start over here and as i go i + + + align:start position:0% +this and i start over here and as i go i +know that that my wheels slip or + + align:start position:0% +know that that my wheels slip or + + + align:start position:0% +know that that my wheels slip or +something like that my distributions are + + align:start position:0% +something like that my distributions are + + + align:start position:0% +something like that my distributions are +going to grow + + align:start position:0% +going to grow + + + align:start position:0% +going to grow +as i go yeah and i've got some ability + + align:start position:0% +as i go yeah and i've got some ability + + + align:start position:0% +as i go yeah and i've got some ability +to control them so they're not going to + + align:start position:0% +to control them so they're not going to + + + align:start position:0% +to control them so they're not going to +grow unbounded but let's say they're + + align:start position:0% +grow unbounded but let's say they're + + + align:start position:0% +grow unbounded but let's say they're +going to grow + + align:start position:0% +going to grow + + + align:start position:0% +going to grow +my path to the goal okay + + align:start position:0% +my path to the goal okay + + + align:start position:0% +my path to the goal okay +there'll be two competing forces + + align:start position:0% +there'll be two competing forces + + + align:start position:0% +there'll be two competing forces +there'll be the ability to to measure + + align:start position:0% +there'll be the ability to to measure + + + align:start position:0% +there'll be the ability to to measure +and and + + align:start position:0% +and and + + + align:start position:0% +and and +fight against disturbances and there'll + + align:start position:0% +fight against disturbances and there'll + + + align:start position:0% +fight against disturbances and there'll +be the inevitable disturbances and those + + align:start position:0% +be the inevitable disturbances and those + + + align:start position:0% +be the inevitable disturbances and those +two will again combine into some sort of + + align:start position:0% +two will again combine into some sort of + + + align:start position:0% +two will again combine into some sort of +distribution over time okay + + align:start position:0% +distribution over time okay + + + align:start position:0% +distribution over time okay +now imagine + + align:start position:0% +now imagine + + + align:start position:0% +now imagine +like the scenario we talked about in the + + align:start position:0% +like the scenario we talked about in the + + + align:start position:0% +like the scenario we talked about in the +feedback case imagine + + align:start position:0% +feedback case imagine + + + align:start position:0% +feedback case imagine +my cost function + + align:start position:0% + + + + align:start position:0% + +is like is zero everywhere + + align:start position:0% +is like is zero everywhere + + + align:start position:0% +is like is zero everywhere +you know + + align:start position:0% + + + + align:start position:0% + +negative one at the goal + + align:start position:0% +negative one at the goal + + + align:start position:0% +negative one at the goal +i want to get to the goal + + align:start position:0% +i want to get to the goal + + + align:start position:0% +i want to get to the goal +and say you know + + align:start position:0% + + + + align:start position:0% + +something really big here yeah + + align:start position:0% +something really big here yeah + + + align:start position:0% +something really big here yeah +right there's sort of pits of fire in + + align:start position:0% +right there's sort of pits of fire in + + + align:start position:0% +right there's sort of pits of fire in +the middle of the lab + + align:start position:0% +the middle of the lab + + + align:start position:0% +the middle of the lab +okay + + align:start position:0% +okay + + + align:start position:0% +okay +no i mean right so so i've got to make + + align:start position:0% +no i mean right so so i've got to make + + + align:start position:0% +no i mean right so so i've got to make +the point if it was one if it was just + + align:start position:0% +the point if it was one if it was just + + + align:start position:0% +the point if it was one if it was just +one i wouldn't make be as dramatic but + + align:start position:0% +one i wouldn't make be as dramatic but + + + align:start position:0% +one i wouldn't make be as dramatic but +um + + align:start position:0% + + + + align:start position:0% + +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +long story short + + align:start position:0% +long story short + + + align:start position:0% +long story short +a stochastic optimal control solution + + align:start position:0% +a stochastic optimal control solution + + + align:start position:0% +a stochastic optimal control solution +is unlikely to choose this path + + align:start position:0% + + + + align:start position:0% + +because + + align:start position:0% +because + + + align:start position:0% +because +zero + + align:start position:0% +zero + + + align:start position:0% +zero +even if even if the distributions are + + align:start position:0% +even if even if the distributions are + + + align:start position:0% +even if even if the distributions are +fairly tight + + align:start position:0% +fairly tight + + + align:start position:0% +fairly tight +zero times a big part of the probability + + align:start position:0% +zero times a big part of the probability + + + align:start position:0% +zero times a big part of the probability +distribution + + align:start position:0% +distribution + + + align:start position:0% +distribution +plus + + align:start position:0% +plus + + + align:start position:0% +plus +one e to the sixth times even a little + + align:start position:0% +one e to the sixth times even a little + + + align:start position:0% +one e to the sixth times even a little +part of the probability distribution is + + align:start position:0% +part of the probability distribution is + + + align:start position:0% +part of the probability distribution is +still a big number + + align:start position:0% +still a big number + + + align:start position:0% +still a big number +okay and so therefore there's a there's + + align:start position:0% +okay and so therefore there's a there's + + + align:start position:0% +okay and so therefore there's a there's +the expected value of going through here + + align:start position:0% +the expected value of going through here + + + align:start position:0% +the expected value of going through here +is that i'm going to incur quite a bit + + align:start position:0% +is that i'm going to incur quite a bit + + + align:start position:0% +is that i'm going to incur quite a bit +of cost does that make sense + + align:start position:0% +of cost does that make sense + + + align:start position:0% +of cost does that make sense +so so if i just did deterministic + + align:start position:0% +so so if i just did deterministic + + + align:start position:0% +so so if i just did deterministic +optimal control right we talked about + + align:start position:0% +optimal control right we talked about + + + align:start position:0% +optimal control right we talked about +using feedback to try to motivate not + + align:start position:0% +using feedback to try to motivate not + + + align:start position:0% +using feedback to try to motivate not +going through there but the really the + + align:start position:0% +going through there but the really the + + + align:start position:0% +going through there but the really the +more direct way is to think about + + align:start position:0% +more direct way is to think about + + + align:start position:0% +more direct way is to think about +the probability distributions right + + align:start position:0% +the probability distributions right + + + align:start position:0% +the probability distributions right +so if i can control my probabilities to + + align:start position:0% +so if i can control my probabilities to + + + align:start position:0% +so if i can control my probabilities to +the point where i know zero probability + + align:start position:0% +the point where i know zero probability + + + align:start position:0% +the point where i know zero probability +is going to be in here then sure go + + align:start position:0% +is going to be in here then sure go + + + align:start position:0% +is going to be in here then sure go +ahead through there and the + + align:start position:0% +ahead through there and the + + + align:start position:0% +ahead through there and the +deterministic one will probably find + + align:start position:0% +deterministic one will probably find + + + align:start position:0% +deterministic one will probably find +that + + align:start position:0% +that + + + align:start position:0% +that +but the stochastic one if it realizes + + align:start position:0% +but the stochastic one if it realizes + + + align:start position:0% +but the stochastic one if it realizes +there's something we'll probably try to + + align:start position:0% +there's something we'll probably try to + + + align:start position:0% +there's something we'll probably try to +find a different path + + align:start position:0% +find a different path + + + align:start position:0% +find a different path +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so that's a that's a + + align:start position:0% +so that's a that's a + + + align:start position:0% +so that's a that's a +uh one example but in general the + + align:start position:0% +uh one example but in general the + + + align:start position:0% +uh one example but in general the +stochastic optimal control policies are + + align:start position:0% +stochastic optimal control policies are + + + align:start position:0% +stochastic optimal control policies are +going to be different + + align:start position:0% +going to be different + + + align:start position:0% +going to be different +than the deterministic ones and and + + align:start position:0% +than the deterministic ones and and + + + align:start position:0% +than the deterministic ones and and +better and if you can if you have a + + align:start position:0% +better and if you can if you have a + + + align:start position:0% +better and if you can if you have a +reasonable model of the + + align:start position:0% +reasonable model of the + + + align:start position:0% +reasonable model of the +disturbances you'd expect to encounter + + align:start position:0% +disturbances you'd expect to encounter + + + align:start position:0% +disturbances you'd expect to encounter +then you should allow your optimal + + align:start position:0% +then you should allow your optimal + + + align:start position:0% +then you should allow your optimal +control tools to think about them + + align:start position:0% +control tools to think about them + + + align:start position:0% +control tools to think about them +okay + + align:start position:0% + + + + align:start position:0% + +because + + align:start position:0% +because + + + align:start position:0% +because +potentially each action can + + align:start position:0% +potentially each action can + + + align:start position:0% +potentially each action can +move you to any of the possible states + + align:start position:0% +move you to any of the possible states + + + align:start position:0% +move you to any of the possible states +well and deterministic case you can go + + align:start position:0% +well and deterministic case you can go + + + align:start position:0% +well and deterministic case you can go +to one state so when you do it back up + + align:start position:0% +to one state so when you do it back up + + + align:start position:0% +to one state so when you do it back up +this time it's slower + + align:start position:0% +this time it's slower + + + align:start position:0% +this time it's slower +right i knew someone was gonna so so i + + align:start position:0% +right i knew someone was gonna so so i + + + align:start position:0% +right i knew someone was gonna so so i +would say like you know essentially no i + + align:start position:0% +would say like you know essentially no i + + + align:start position:0% +would say like you know essentially no i +almost wrote essentially no time and the + + align:start position:0% +almost wrote essentially no time and the + + + align:start position:0% +almost wrote essentially no time and the +reason i want to make that comparison + + align:start position:0% +reason i want to make that comparison + + + align:start position:0% +reason i want to make that comparison +actually is because i want to compare it + + align:start position:0% +actually is because i want to compare it + + + align:start position:0% +actually is because i want to compare it +directly to the barycentric + + align:start position:0% +directly to the barycentric + + + align:start position:0% +directly to the barycentric +interpolation that we were doing before + + align:start position:0% +interpolation that we were doing before + + + align:start position:0% +interpolation that we were doing before +which is what i'm going to do in a + + align:start position:0% +which is what i'm going to do in a + + + align:start position:0% +which is what i'm going to do in a +second and that is already doing an + + align:start position:0% +second and that is already doing an + + + align:start position:0% +second and that is already doing an +interpolation already going through some + + align:start position:0% +interpolation already going through some + + + align:start position:0% +interpolation already going through some +probability + + align:start position:0% +probability + + + align:start position:0% +probability +some some transition matrix yeah + + align:start position:0% +some some transition matrix yeah + + + align:start position:0% +some some transition matrix yeah +and it's probably true that the it may + + align:start position:0% +and it's probably true that the it may + + + align:start position:0% +and it's probably true that the it may +be true depending on your noise + + align:start position:0% +be true depending on your noise + + + align:start position:0% +be true depending on your noise +distributions that if you add a lot of + + align:start position:0% +distributions that if you add a lot of + + + align:start position:0% +distributions that if you add a lot of +noise that transition matrix will be + + align:start position:0% +noise that transition matrix will be + + + align:start position:0% +noise that transition matrix will be +more dense and therefore it might take + + align:start position:0% +more dense and therefore it might take + + + align:start position:0% +more dense and therefore it might take +more time depending on how you compute + + align:start position:0% +more time depending on how you compute + + + align:start position:0% +more time depending on how you compute +it + + align:start position:0% +it + + + align:start position:0% +it +my matlab implementation is the same + + align:start position:0% +my matlab implementation is the same + + + align:start position:0% +my matlab implementation is the same +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +is that fair + + align:start position:0% +is that fair + + + align:start position:0% +is that fair +and it's no more complicated to write + + align:start position:0% +and it's no more complicated to write + + + align:start position:0% +and it's no more complicated to write +down how about that + + align:start position:0% +down how about that + + + align:start position:0% +down how about that +okay + + align:start position:0% + + + + align:start position:0% + +we'll completely understand what what + + align:start position:0% +we'll completely understand what what + + + align:start position:0% +we'll completely understand what what +upwards was asking in just a second + + align:start position:0% +upwards was asking in just a second + + + align:start position:0% +upwards was asking in just a second +okay so why is it no more complicated + + align:start position:0% +okay so why is it no more complicated + + + align:start position:0% +okay so why is it no more complicated +to write for me to write down on the + + align:start position:0% +to write for me to write down on the + + + align:start position:0% +to write for me to write down on the +board the stochastic uh optimal control + + align:start position:0% +board the stochastic uh optimal control + + + align:start position:0% +board the stochastic uh optimal control +case in dynamic programming right um + + align:start position:0% + + + + align:start position:0% + +remember i said now this is i'm going to + + align:start position:0% +remember i said now this is i'm going to + + + align:start position:0% +remember i said now this is i'm going to +take the expected value of my additive + + align:start position:0% +take the expected value of my additive + + + align:start position:0% +take the expected value of my additive +cost right + + align:start position:0% + + + + align:start position:0% + +so first let's just think about what the + + align:start position:0% +so first let's just think about what the + + + align:start position:0% +so first let's just think about what the +implications are for for doing optimal + + align:start position:0% +implications are for for doing optimal + + + align:start position:0% +implications are for for doing optimal +control + + align:start position:0% + + + + align:start position:0% + +right so first of all i can take that + + align:start position:0% +right so first of all i can take that + + + align:start position:0% +right so first of all i can take that +expectation inside + + align:start position:0% + + + + align:start position:0% + +all right + + align:start position:0% +all right + + + align:start position:0% +all right +and now what's the probability of + + align:start position:0% +and now what's the probability of + + + align:start position:0% +and now what's the probability of +g + + align:start position:0% +g + + + align:start position:0% +g +or that what's the expected value of g + + align:start position:0% +or that what's the expected value of g + + + align:start position:0% +or that what's the expected value of g +at x and u n + + align:start position:0% +at x and u n + + + align:start position:0% +at x and u n +well + + align:start position:0% + + + + align:start position:0% + +x has got some distribution given by p + + align:start position:0% +x has got some distribution given by p + + + align:start position:0% +x has got some distribution given by p +of x and yeah + + align:start position:0% +of x and yeah + + + align:start position:0% +of x and yeah +so it's this thing is going to work out + + align:start position:0% +so it's this thing is going to work out + + + align:start position:0% +so it's this thing is going to work out +to be you can always take the expected + + align:start position:0% +to be you can always take the expected + + + align:start position:0% +to be you can always take the expected +value of a function of x by just the + + align:start position:0% +value of a function of x by just the + + + align:start position:0% +value of a function of x by just the +that function times this distribution + + align:start position:0% +that function times this distribution + + + align:start position:0% +that function times this distribution +integrated this thing is going to work + + align:start position:0% +integrated this thing is going to work + + + align:start position:0% +integrated this thing is going to work +out to be + + align:start position:0% + + + + align:start position:0% + +some integral over all possible states + + align:start position:0% +some integral over all possible states + + + align:start position:0% +some integral over all possible states +of g + + align:start position:0% +of g + + + align:start position:0% +of g +of x + + align:start position:0% +of x + + + align:start position:0% +of x +u of n + + align:start position:0% +u of n + + + align:start position:0% +u of n +times p then + + align:start position:0% +times p then + + + align:start position:0% +times p then +x dx + + align:start position:0% + + + + align:start position:0% + +right + + align:start position:0% + + + + align:start position:0% + +okay so you could imagine computing + + align:start position:0% +okay so you could imagine computing + + + align:start position:0% +okay so you could imagine computing +optimal policies by + + align:start position:0% +optimal policies by + + + align:start position:0% +optimal policies by +um + + align:start position:0% +um + + + align:start position:0% +um +figuring out the state distribution by + + align:start position:0% +figuring out the state distribution by + + + align:start position:0% +figuring out the state distribution by +that evolution i was talking about + + align:start position:0% +that evolution i was talking about + + + align:start position:0% +that evolution i was talking about +before right and then + + align:start position:0% +before right and then + + + align:start position:0% +before right and then +integrating over the possible states + + align:start position:0% +integrating over the possible states + + + align:start position:0% +integrating over the possible states +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +and the the costs for each state and + + align:start position:0% +and the the costs for each state and + + + align:start position:0% +and the the costs for each state and +figuring out our j figuring out a way to + + align:start position:0% +figuring out our j figuring out a way to + + + align:start position:0% +figuring out our j figuring out a way to +minimize that right i sort of only wrote + + align:start position:0% +minimize that right i sort of only wrote + + + align:start position:0% +minimize that right i sort of only wrote +that down to make it look hard okay + + align:start position:0% +that down to make it look hard okay + + + align:start position:0% +that down to make it look hard okay +turns out again just like before the + + align:start position:0% +turns out again just like before the + + + align:start position:0% +turns out again just like before the +recursive form is beautiful and simple + + align:start position:0% +recursive form is beautiful and simple + + + align:start position:0% +recursive form is beautiful and simple +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so you can imagine doing it that way and + + align:start position:0% +so you can imagine doing it that way and + + + align:start position:0% +so you can imagine doing it that way and +that's really that's that's correct + + align:start position:0% +that's really that's that's correct + + + align:start position:0% +that's really that's that's correct +but just like before the dynamic + + align:start position:0% +but just like before the dynamic + + + align:start position:0% +but just like before the dynamic +programming solution exploits the + + align:start position:0% +programming solution exploits the + + + align:start position:0% +programming solution exploits the +recursive the additive form and does it + + align:start position:0% +recursive the additive form and does it + + + align:start position:0% +recursive the additive form and does it +a recursive solution which just works + + align:start position:0% +a recursive solution which just works + + + align:start position:0% +a recursive solution which just works +out beautifully okay + + align:start position:0% +out beautifully okay + + + align:start position:0% +out beautifully okay +so + + align:start position:0% + + + + align:start position:0% + +so if i do + + align:start position:0% +so if i do + + + align:start position:0% +so if i do +j of x from time 0 being the expected + + align:start position:0% +j of x from time 0 being the expected + + + align:start position:0% +j of x from time 0 being the expected +value of + + align:start position:0% +value of + + + align:start position:0% +value of +let's do the final cost + + align:start position:0% +let's do the final cost + + + align:start position:0% +let's do the final cost +also + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% + + + + align:start position:0% + +what's j of x + + align:start position:0% +what's j of x + + + align:start position:0% +what's j of x +capital n + + align:start position:0% + + + + align:start position:0% + +my cost to go given i'm at the goal + + align:start position:0% +my cost to go given i'm at the goal + + + align:start position:0% +my cost to go given i'm at the goal +all right the time is the time is + + align:start position:0% +all right the time is the time is + + + align:start position:0% +all right the time is the time is +expired and i'm at state x + + align:start position:0% + + + + align:start position:0% + +is it expected value of h of x + + align:start position:0% +is it expected value of h of x + + + align:start position:0% +is it expected value of h of x +or is it just h what is it + + align:start position:0% + + + + align:start position:0% + +awesome yeah if i know i'm already in + + align:start position:0% +awesome yeah if i know i'm already in + + + align:start position:0% +awesome yeah if i know i'm already in +x + + align:start position:0% +x + + + align:start position:0% +x +then + + align:start position:0% +then + + + align:start position:0% +then +there's no probabilities left yeah + + align:start position:0% + + + + align:start position:0% + +okay and then if i go backwards + + align:start position:0% + + + + align:start position:0% + +j of x of time + + align:start position:0% +j of x of time + + + align:start position:0% +j of x of time +k + + align:start position:0% + + + + align:start position:0% + +is going to work out to be + + align:start position:0% +is going to work out to be + + + align:start position:0% +is going to work out to be +min over u i should say j star of x + + align:start position:0% +min over u i should say j star of x + + + align:start position:0% +min over u i should say j star of x +sorry + + align:start position:0% +sorry + + + align:start position:0% +sorry +j star of x is going to be min over u + + align:start position:0% +j star of x is going to be min over u + + + align:start position:0% +j star of x is going to be min over u +the expected value of g x + + align:start position:0% +the expected value of g x + + + align:start position:0% +the expected value of g x +u + + align:start position:0% +u + + + align:start position:0% +u +plus j + + align:start position:0% +plus j + + + align:start position:0% +plus j +star + + align:start position:0% +star + + + align:start position:0% +star +of + + align:start position:0% + + + + align:start position:0% + +f + + align:start position:0% +f + + + align:start position:0% +f +x + + align:start position:0% + + + + align:start position:0% + +u + + align:start position:0% +u + + + align:start position:0% +u +w of n + + align:start position:0% + + + + align:start position:0% + +k plus one + + align:start position:0% + + + + align:start position:0% + +can you buy that + + align:start position:0% + + + + align:start position:0% + +okay so the reinforcement learning + + align:start position:0% +okay so the reinforcement learning + + + align:start position:0% +okay so the reinforcement learning +people + + align:start position:0% +people + + + align:start position:0% +people +always like to say that + + align:start position:0% +always like to say that + + + align:start position:0% +always like to say that +the reward or the cost + + align:start position:0% +the reward or the cost + + + align:start position:0% +the reward or the cost +can also be + + align:start position:0% +can also be + + + align:start position:0% +can also be +a random + + align:start position:0% +a random + + + align:start position:0% +a random +process or random variable + + align:start position:0% +process or random variable + + + align:start position:0% +process or random variable +i'm always in this case where i design + + align:start position:0% +i'm always in this case where i design + + + align:start position:0% +i'm always in this case where i design +the cost + + align:start position:0% +the cost + + + align:start position:0% +the cost +it's a function of some random x but g + + align:start position:0% +it's a function of some random x but g + + + align:start position:0% +it's a function of some random x but g +is deterministic so actually i could + + align:start position:0% +is deterministic so actually i could + + + align:start position:0% +is deterministic so actually i could +take that expectation right inside here + + align:start position:0% +take that expectation right inside here + + + align:start position:0% +take that expectation right inside here +right + + align:start position:0% +right + + + align:start position:0% +right +and i just have to do a min over u of g + + align:start position:0% +and i just have to do a min over u of g + + + align:start position:0% +and i just have to do a min over u of g +of x + + align:start position:0% +of x + + + align:start position:0% +of x +that's the expected value of my cost to + + align:start position:0% +that's the expected value of my cost to + + + align:start position:0% +that's the expected value of my cost to +go + + align:start position:0% +go + + + align:start position:0% +go +okay + + align:start position:0% + + + + align:start position:0% + +the nicest way to see how to implement + + align:start position:0% +the nicest way to see how to implement + + + align:start position:0% +the nicest way to see how to implement +that is let's go ahead and + + align:start position:0% +that is let's go ahead and + + + align:start position:0% +that is let's go ahead and +we've already discretized time let's + + align:start position:0% +we've already discretized time let's + + + align:start position:0% +we've already discretized time let's +discretize state and actions + + align:start position:0% + + + + align:start position:0% + +so now i have + + align:start position:0% +so now i have + + + align:start position:0% +so now i have +s of n plus one remember i switched to + + align:start position:0% +s of n plus one remember i switched to + + + align:start position:0% +s of n plus one remember i switched to +the s's and a's when i discretize things + + align:start position:0% +the s's and a's when i discretize things + + + align:start position:0% +the s's and a's when i discretize things +is now f of s n + + align:start position:0% +is now f of s n + + + align:start position:0% +is now f of s n +times some action + + align:start position:0% +times some action + + + align:start position:0% +times some action +times my + + align:start position:0% +times my + + + align:start position:0% +times my +noise + + align:start position:0% +noise + + + align:start position:0% +noise +and the advantage of discretizing state + + align:start position:0% +and the advantage of discretizing state + + + align:start position:0% +and the advantage of discretizing state +in actions is now i can do + + align:start position:0% + + + + align:start position:0% + +p of n plus 1 + + align:start position:0% +p of n plus 1 + + + align:start position:0% +p of n plus 1 +which is a function of s + + align:start position:0% + + + + align:start position:0% + +i can think of that as just a vector + + align:start position:0% +i can think of that as just a vector + + + align:start position:0% +i can think of that as just a vector +where the i th element + + align:start position:0% + + + + align:start position:0% + +is the probability + + align:start position:0% +is the probability + + + align:start position:0% +is the probability +that s + + align:start position:0% +that s + + + align:start position:0% +that s +of n plus one + + align:start position:0% +of n plus one + + + align:start position:0% +of n plus one +equals + + align:start position:0% +equals + + + align:start position:0% +equals +s i + + align:start position:0% + + + + align:start position:0% + +is that okay + + align:start position:0% + + + + align:start position:0% + +my probability distribution remember in + + align:start position:0% +my probability distribution remember in + + + align:start position:0% +my probability distribution remember in +general was a function in the in the + + align:start position:0% +general was a function in the in the + + + align:start position:0% +general was a function in the in the +in the particle in a bowl case it was a + + align:start position:0% +in the particle in a bowl case it was a + + + align:start position:0% +in the particle in a bowl case it was a +continuous gaussian function right + + align:start position:0% +continuous gaussian function right + + + align:start position:0% +continuous gaussian function right +if i discretize the state there + + align:start position:0% +if i discretize the state there + + + align:start position:0% +if i discretize the state there +then i can represent that as a vector + + align:start position:0% +then i can represent that as a vector + + + align:start position:0% +then i can represent that as a vector +saying what's the probability of being + + align:start position:0% +saying what's the probability of being + + + align:start position:0% +saying what's the probability of being +in state 1 what's the probability of + + align:start position:0% +in state 1 what's the probability of + + + align:start position:0% +in state 1 what's the probability of +being in state 2 probability state 3 and + + align:start position:0% +being in state 2 probability state 3 and + + + align:start position:0% +being in state 2 probability state 3 and +so on + + align:start position:0% +so on + + + align:start position:0% +so on +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so the reason to discretize states is i + + align:start position:0% +so the reason to discretize states is i + + + align:start position:0% +so the reason to discretize states is i +can turn my continuous function into a + + align:start position:0% +can turn my continuous function into a + + + align:start position:0% +can turn my continuous function into a +into a vector + + align:start position:0% +into a vector + + + align:start position:0% +into a vector +yeah + + align:start position:0% + + + + align:start position:0% + +and i can turn this function into a into + + align:start position:0% +and i can turn this function into a into + + + align:start position:0% +and i can turn this function into a into +a transition probability matrix right + + align:start position:0% +a transition probability matrix right + + + align:start position:0% +a transition probability matrix right +i can + + align:start position:0% +i can + + + align:start position:0% +i can +so f + + align:start position:0% +so f + + + align:start position:0% +so f +goes to + + align:start position:0% +goes to + + + align:start position:0% +goes to +t i j + + align:start position:0% +t i j + + + align:start position:0% +t i j +which is the probability + + align:start position:0% +which is the probability + + + align:start position:0% +which is the probability +of + + align:start position:0% +of + + + align:start position:0% +of +landing in s j i should depends on the + + align:start position:0% +landing in s j i should depends on the + + + align:start position:0% +landing in s j i should depends on the +actions + + align:start position:0% +actions + + + align:start position:0% +actions +given i was in s i and i took action a + + align:start position:0% + + + + align:start position:0% + +this is a matrix + + align:start position:0% +this is a matrix + + + align:start position:0% +this is a matrix +it's the transition matrix + + align:start position:0% + + + + align:start position:0% + +and now + + align:start position:0% +and now + + + align:start position:0% +and now +the + + align:start position:0% +the + + + align:start position:0% +the +state distribution dynamics + + align:start position:0% + + + + align:start position:0% + +are going to just turn out to be + + align:start position:0% + + + + align:start position:0% + +a pretty simple matrix equation that's + + align:start position:0% +a pretty simple matrix equation that's + + + align:start position:0% +a pretty simple matrix equation that's +in + + align:start position:0% +in + + + align:start position:0% +in +uh oops + + align:start position:0% +uh oops + + + align:start position:0% +uh oops +t i j p j at time + + align:start position:0% +t i j p j at time + + + align:start position:0% +t i j p j at time +um n plus one yeah so let me actually + + align:start position:0% +um n plus one yeah so let me actually + + + align:start position:0% +um n plus one yeah so let me actually +write the whole the real vector form + + align:start position:0% +write the whole the real vector form + + + align:start position:0% +write the whole the real vector form +that's really that's for a single + + align:start position:0% +that's really that's for a single + + + align:start position:0% +that's really that's for a single +element of it + + align:start position:0% +element of it + + + align:start position:0% +element of it +i could just write if i if i'm doing it + + align:start position:0% +i could just write if i if i'm doing it + + + align:start position:0% +i could just write if i if i'm doing it +in + + align:start position:0% +in + + + align:start position:0% +in +in + + align:start position:0% +in + + + align:start position:0% +in +column vectors then it's actually going + + align:start position:0% +column vectors then it's actually going + + + align:start position:0% +column vectors then it's actually going +to be + + align:start position:0% +to be + + + align:start position:0% +to be +p of n + + align:start position:0% +p of n + + + align:start position:0% +p of n +times t of a + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +where + + align:start position:0% +where + + + align:start position:0% +where +this is these two are vectors that's a + + align:start position:0% +this is these two are vectors that's a + + + align:start position:0% +this is these two are vectors that's a +matrix + + align:start position:0% + + + + align:start position:0% + +so and this is the + + align:start position:0% +so and this is the + + + align:start position:0% +so and this is the +discrete + + align:start position:0% +discrete + + + align:start position:0% +discrete +time + + align:start position:0% +time + + + align:start position:0% +time +discrete + + align:start position:0% +discrete + + + align:start position:0% +discrete +action + + align:start position:0% +action + + + align:start position:0% +action +discrete state + + align:start position:0% + + + + align:start position:0% + +master equation + + align:start position:0% + + + + align:start position:0% + +i use it as a column vector + + align:start position:0% + + + + align:start position:0% + +let's make sure so so + + align:start position:0% +let's make sure so so + + + align:start position:0% +let's make sure so so +the probability of being + + align:start position:0% +the probability of being + + + align:start position:0% +the probability of being +in um + + align:start position:0% +in um + + + align:start position:0% +in um +state j + + align:start position:0% +state j + + + align:start position:0% +state j +given i was in state i + + align:start position:0% +given i was in state i + + + align:start position:0% +given i was in state i +should be the sum over + + align:start position:0% +should be the sum over + + + align:start position:0% +should be the sum over +um + + align:start position:0% +um + + + align:start position:0% +um +all right this thing + + align:start position:0% +all right this thing + + + align:start position:0% +all right this thing +probability of + + align:start position:0% +probability of + + + align:start position:0% +probability of +um being of s + + align:start position:0% +um being of s + + + align:start position:0% +um being of s +n plus one + + align:start position:0% +n plus one + + + align:start position:0% +n plus one +um + + align:start position:0% + + + + align:start position:0% + +is the probability what's that + + align:start position:0% +is the probability what's that + + + align:start position:0% +is the probability what's that +i think i had it right right + + align:start position:0% +i think i had it right right + + + align:start position:0% +i think i had it right right +it's it's not true but but i think + + align:start position:0% +it's it's not true but but i think + + + align:start position:0% +it's it's not true but but i think +that's right + + align:start position:0% + + + + align:start position:0% + +i need a t transpose + + align:start position:0% +i need a t transpose + + + align:start position:0% +i need a t transpose +you just can't hit uh + + align:start position:0% +you just can't hit uh + + + align:start position:0% +you just can't hit uh +oh of course because i did this okay + + align:start position:0% +oh of course because i did this okay + + + align:start position:0% +oh of course because i did this okay +yeah sorry + + align:start position:0% +yeah sorry + + + align:start position:0% +yeah sorry +yeah i think the way i've got t defined + + align:start position:0% +yeah i think the way i've got t defined + + + align:start position:0% +yeah i think the way i've got t defined +but thank you that should be a transpose + + align:start position:0% +but thank you that should be a transpose + + + align:start position:0% +but thank you that should be a transpose +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +good + + align:start position:0% + + + + align:start position:0% + +in which case i could + + align:start position:0% +in which case i could + + + align:start position:0% +in which case i could +have written it with the t the transpose + + align:start position:0% +have written it with the t the transpose + + + align:start position:0% +have written it with the t the transpose +too but + + align:start position:0% +too but + + + align:start position:0% +too but +if i transpose the whole thing + + align:start position:0% + + + + align:start position:0% + +it doesn't really matter if you like row + + align:start position:0% +it doesn't really matter if you like row + + + align:start position:0% +it doesn't really matter if you like row +vectors or column vectors the point is + + align:start position:0% +vectors or column vectors the point is + + + align:start position:0% +vectors or column vectors the point is +the master equation which looked a + + align:start position:0% +the master equation which looked a + + + align:start position:0% +the master equation which looked a +little scary before + + align:start position:0% +little scary before + + + align:start position:0% +little scary before +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +turns into a simple matrix update in the + + align:start position:0% +turns into a simple matrix update in the + + + align:start position:0% +turns into a simple matrix update in the +discrete time discrete state case + + align:start position:0% + + + + align:start position:0% + +do you yeah use non-capturing things + + align:start position:0% +do you yeah use non-capturing things + + + align:start position:0% +do you yeah use non-capturing things +because you you have hardcover + + align:start position:0% + + + + align:start position:0% + +good so there's a question again just + + align:start position:0% +good so there's a question again just + + + align:start position:0% +good so there's a question again just +like we had the question in the + + align:start position:0% +like we had the question in the + + + align:start position:0% +like we had the question in the +in the you know when we did the + + align:start position:0% +in the you know when we did the + + + align:start position:0% +in the you know when we did the +dynamic programming for the value + + align:start position:0% +dynamic programming for the value + + + align:start position:0% +dynamic programming for the value +iteration of how you go from the + + align:start position:0% +iteration of how you go from the + + + align:start position:0% +iteration of how you go from the +continuous probabilities and continuous + + align:start position:0% +continuous probabilities and continuous + + + align:start position:0% +continuous probabilities and continuous +states back to the other one so again + + align:start position:0% +states back to the other one so again + + + align:start position:0% +states back to the other one so again +yeah so i would i would sample for my + + align:start position:0% +yeah so i would i would sample for my + + + align:start position:0% +yeah so i would i would sample for my +gaussian and fill out a transition + + align:start position:0% +gaussian and fill out a transition + + + align:start position:0% +gaussian and fill out a transition +probabilities as a close truncated + + align:start position:0% +probabilities as a close truncated + + + align:start position:0% +probabilities as a close truncated +representation of the gaussian + + align:start position:0% +representation of the gaussian + + + align:start position:0% +representation of the gaussian +and still interpolate + + align:start position:0% +and still interpolate + + + align:start position:0% +and still interpolate +with the + + align:start position:0% +with the + + + align:start position:0% +with the +barycentric interpolators + + align:start position:0% + + + + align:start position:0% + +and now + + align:start position:0% + + + + align:start position:0% + +the dp update works out to be just a + + align:start position:0% +the dp update works out to be just a + + + align:start position:0% +the dp update works out to be just a +simple if i'm + + align:start position:0% + + + + align:start position:0% + +the probability of being in + + align:start position:0% + + + + align:start position:0% + +s + + align:start position:0% +s + + + align:start position:0% +s +let's see s + + align:start position:0% +let's see s + + + align:start position:0% +let's see s +j + + align:start position:0% +j + + + align:start position:0% +j +is the min over a + + align:start position:0% +is the min over a + + + align:start position:0% +is the min over a +the expected value from this equation + + align:start position:0% +the expected value from this equation + + + align:start position:0% +the expected value from this equation +can be taken care of with just the + + align:start position:0% +can be taken care of with just the + + + align:start position:0% +can be taken care of with just the +the transition matrix over here and i + + align:start position:0% +the transition matrix over here and i + + + align:start position:0% +the transition matrix over here and i +get + + align:start position:0% +get + + + align:start position:0% +get +maybe my vector g of a which is the cost + + align:start position:0% +maybe my vector g of a which is the cost + + + align:start position:0% +maybe my vector g of a which is the cost +of being in each + + align:start position:0% +of being in each + + + align:start position:0% +of being in each +state + + align:start position:0% +state + + + align:start position:0% +state +given i took that action + + align:start position:0% +given i took that action + + + align:start position:0% +given i took that action +sum over j + + align:start position:0% +sum over j + + + align:start position:0% +sum over j +t i j + + align:start position:0% +t i j + + + align:start position:0% +t i j +s j + + align:start position:0% + + + + align:start position:0% + +j of sj + + align:start position:0% +j of sj + + + align:start position:0% +j of sj +k plus 1. yeah + + align:start position:0% + + + + align:start position:0% + +and i got i get rid of my uh expected + + align:start position:0% +and i got i get rid of my uh expected + + + align:start position:0% +and i got i get rid of my uh expected +values by just using that + + align:start position:0% +values by just using that + + + align:start position:0% +values by just using that +working directly with the transition + + align:start position:0% +working directly with the transition + + + align:start position:0% +working directly with the transition +matrices + + align:start position:0% + + + + align:start position:0% + +i on this side + + align:start position:0% +i on this side + + + align:start position:0% +i on this side +j on this side many apologies + + align:start position:0% + + + + align:start position:0% + +this turns out to be exactly the reason + + align:start position:0% +this turns out to be exactly the reason + + + align:start position:0% +this turns out to be exactly the reason +i said + + align:start position:0% +i said + + + align:start position:0% +i said +basically no more expensive to solve + + align:start position:0% +basically no more expensive to solve + + + align:start position:0% +basically no more expensive to solve +than the deterministic case is we + + align:start position:0% +than the deterministic case is we + + + align:start position:0% +than the deterministic case is we +already used this form + + align:start position:0% + + + + align:start position:0% + +when we were doing the barycentric + + align:start position:0% +when we were doing the barycentric + + + align:start position:0% +when we were doing the barycentric +interpolation + + align:start position:0% +interpolation + + + align:start position:0% +interpolation +because our our problem in the the + + align:start position:0% +because our our problem in the the + + + align:start position:0% +because our our problem in the the +dynamic programming originally + + align:start position:0% +dynamic programming originally + + + align:start position:0% +dynamic programming originally +was + + align:start position:0% + + + + align:start position:0% + +that when we started simulating this + + align:start position:0% +that when we started simulating this + + + align:start position:0% +that when we started simulating this +thing from from one node + + align:start position:0% +thing from from one node + + + align:start position:0% +thing from from one node +forward it didn't end up you know + + align:start position:0% +forward it didn't end up you know + + + align:start position:0% +forward it didn't end up you know +unless you were very very lucky it + + align:start position:0% +unless you were very very lucky it + + + align:start position:0% +unless you were very very lucky it +didn't end up right on top of another + + align:start position:0% +didn't end up right on top of another + + + align:start position:0% +didn't end up right on top of another +node + + align:start position:0% +node + + + align:start position:0% +node +so we already had said that we're going + + align:start position:0% +so we already had said that we're going + + + align:start position:0% +so we already had said that we're going +to estimate the new + + align:start position:0% +to estimate the new + + + align:start position:0% +to estimate the new +cost to go as an interpolation of the + + align:start position:0% +cost to go as an interpolation of the + + + align:start position:0% +cost to go as an interpolation of the +neighboring points of the value of the + + align:start position:0% +neighboring points of the value of the + + + align:start position:0% +neighboring points of the value of the +neighboring points where that weighting + + align:start position:0% +neighboring points where that weighting + + + align:start position:0% +neighboring points where that weighting +came from the bary-centric interpolators + + align:start position:0% +came from the bary-centric interpolators + + + align:start position:0% +came from the bary-centric interpolators +okay + + align:start position:0% +okay + + + align:start position:0% +okay +we're doing the exact same thing now + + align:start position:0% +we're doing the exact same thing now + + + align:start position:0% +we're doing the exact same thing now +in fact you could actually think of the + + align:start position:0% +in fact you could actually think of the + + + align:start position:0% +in fact you could actually think of the +barycentric interpolators as turning + + align:start position:0% +barycentric interpolators as turning + + + align:start position:0% +barycentric interpolators as turning +your deterministic problem into a + + align:start position:0% +your deterministic problem into a + + + align:start position:0% +your deterministic problem into a +stochastic problem + + align:start position:0% +stochastic problem + + + align:start position:0% +stochastic problem +where the probability of going into each + + align:start position:0% +where the probability of going into each + + + align:start position:0% +where the probability of going into each +of these neighbors is the interpolant + + align:start position:0% +of these neighbors is the interpolant + + + align:start position:0% +of these neighbors is the interpolant +okay so the reason the barycentric works + + align:start position:0% +okay so the reason the barycentric works + + + align:start position:0% +okay so the reason the barycentric works +beautifully is is that it fall it turns + + align:start position:0% +beautifully is is that it fall it turns + + + align:start position:0% +beautifully is is that it fall it turns +the deterministic case into a + + align:start position:0% +the deterministic case into a + + + align:start position:0% +the deterministic case into a +stochastic case + + align:start position:0% +stochastic case + + + align:start position:0% +stochastic case +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +and that's why i wanted to say that it's + + align:start position:0% +and that's why i wanted to say that it's + + + align:start position:0% +and that's why i wanted to say that it's +no more complex okay t might be more + + align:start position:0% +no more complex okay t might be more + + + align:start position:0% +no more complex okay t might be more +have less zeros in it in the case the + + align:start position:0% +have less zeros in it in the case the + + + align:start position:0% +have less zeros in it in the case the +general case if maybe with with some + + align:start position:0% +general case if maybe with with some + + + align:start position:0% +general case if maybe with with some +probability distribution it might be + + align:start position:0% +probability distribution it might be + + + align:start position:0% +probability distribution it might be +that i have to worry about hitting a lot + + align:start position:0% +that i have to worry about hitting a lot + + + align:start position:0% +that i have to worry about hitting a lot +more nodes + + align:start position:0% + + + + align:start position:0% + +so it might take more a few more cycles + + align:start position:0% +so it might take more a few more cycles + + + align:start position:0% +so it might take more a few more cycles +but but the equations are the same and + + align:start position:0% +but but the equations are the same and + + + align:start position:0% +but but the equations are the same and +my matlab code is the same + + align:start position:0% +my matlab code is the same + + + align:start position:0% +my matlab code is the same +okay + + align:start position:0% +okay + + + align:start position:0% +okay +simultaneously or maybe conversely this + + align:start position:0% +simultaneously or maybe conversely this + + + align:start position:0% +simultaneously or maybe conversely this +helps actually tells you why we have + + align:start position:0% +helps actually tells you why we have + + + align:start position:0% +helps actually tells you why we have +problems with the barycentric + + align:start position:0% +problems with the barycentric + + + align:start position:0% +problems with the barycentric +interpolators right + + align:start position:0% +interpolators right + + + align:start position:0% +interpolators right +this is the remember the fundamental + + align:start position:0% +this is the remember the fundamental + + + align:start position:0% +this is the remember the fundamental +problems with the barycentric + + align:start position:0% +problems with the barycentric + + + align:start position:0% +problems with the barycentric +interpolators is that things sort of + + align:start position:0% +interpolators is that things sort of + + + align:start position:0% +interpolators is that things sort of +leaked away from the nominal + + align:start position:0% +leaked away from the nominal + + + align:start position:0% +leaked away from the nominal +trajectories and and our we had our + + align:start position:0% +trajectories and and our we had our + + + align:start position:0% +trajectories and and our we had our +chattering happening and the + + align:start position:0% +chattering happening and the + + + align:start position:0% +chattering happening and the +our our bang bang solution wasn't quite + + align:start position:0% +our our bang bang solution wasn't quite + + + align:start position:0% +our our bang bang solution wasn't quite +right + + align:start position:0% +right + + + align:start position:0% +right +because now you can think of it as + + align:start position:0% +because now you can think of it as + + + align:start position:0% +because now you can think of it as +us is my deterministic problem assigning + + align:start position:0% +us is my deterministic problem assigning + + + align:start position:0% +us is my deterministic problem assigning +some probability of going to each of + + align:start position:0% +some probability of going to each of + + + align:start position:0% +some probability of going to each of +these neighbors and you can sort of see + + align:start position:0% +these neighbors and you can sort of see + + + align:start position:0% +these neighbors and you can sort of see +that that distribution is going to start + + align:start position:0% +that that distribution is going to start + + + align:start position:0% +that that distribution is going to start +slipping away from the from the nominal + + align:start position:0% +slipping away from the from the nominal + + + align:start position:0% +slipping away from the from the nominal +trajectory + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +excellent so this is actually + + align:start position:0% +excellent so this is actually + + + align:start position:0% +excellent so this is actually +very important + + align:start position:0% +very important + + + align:start position:0% +very important +stochastic optimal control + + align:start position:0% +stochastic optimal control + + + align:start position:0% +stochastic optimal control +is a beautiful thing if i can if i can + + align:start position:0% +is a beautiful thing if i can if i can + + + align:start position:0% +is a beautiful thing if i can if i can +model the + + align:start position:0% +model the + + + align:start position:0% +model the +the + + align:start position:0% +the + + + align:start position:0% +the +disturbances in any reasonable way + + align:start position:0% +disturbances in any reasonable way + + + align:start position:0% +disturbances in any reasonable way +then i can get better policies by + + align:start position:0% +then i can get better policies by + + + align:start position:0% +then i can get better policies by +explicitly reasoning about them + + align:start position:0% +explicitly reasoning about them + + + align:start position:0% +explicitly reasoning about them +and just like we sort of said dynamic + + align:start position:0% +and just like we sort of said dynamic + + + align:start position:0% +and just like we sort of said dynamic +programming for low dimensional problems + + align:start position:0% +programming for low dimensional problems + + + align:start position:0% +programming for low dimensional problems +solves all these really hard problems + + align:start position:0% +solves all these really hard problems + + + align:start position:0% +solves all these really hard problems +that are analytically untractable and + + align:start position:0% +that are analytically untractable and + + + align:start position:0% +that are analytically untractable and +things like that it can even solve the + + align:start position:0% +things like that it can even solve the + + + align:start position:0% +things like that it can even solve the +stochastic problem with almost no more + + align:start position:0% +stochastic problem with almost no more + + + align:start position:0% +stochastic problem with almost no more +work + + align:start position:0% +work + + + align:start position:0% +work +okay + + align:start position:0% +okay + + + align:start position:0% +okay +low dimensional problems even + + align:start position:0% +low dimensional problems even + + + align:start position:0% +low dimensional problems even +complicated ones with complicated + + align:start position:0% +complicated ones with complicated + + + align:start position:0% +complicated ones with complicated +distributions + + align:start position:0% +distributions + + + align:start position:0% +distributions +dp can do the work for you + + align:start position:0% + + + + align:start position:0% + +okay so + + align:start position:0% + + + + align:start position:0% + +a few more things to say + + align:start position:0% +a few more things to say + + + align:start position:0% +a few more things to say +there's one particular result which we + + align:start position:0% +there's one particular result which we + + + align:start position:0% +there's one particular result which we +already + + align:start position:0% +already + + + align:start position:0% +already +mentioned early + + align:start position:0% + + + + align:start position:0% + +that i have to mention + + align:start position:0% +that i have to mention + + + align:start position:0% +that i have to mention +here + + align:start position:0% + + + + align:start position:0% + +this dynamic programming update + + align:start position:0% + + + + align:start position:0% + +right + + align:start position:0% +right + + + align:start position:0% +right +we use this in the in our analytical + + align:start position:0% +we use this in the in our analytical + + + align:start position:0% +we use this in the in our analytical +optimal control too right we use this as + + align:start position:0% +optimal control too right we use this as + + + align:start position:0% +optimal control too right we use this as +the basis to start designing things like + + align:start position:0% +the basis to start designing things like + + + align:start position:0% +the basis to start designing things like +our lqr controllers + + align:start position:0% +our lqr controllers + + + align:start position:0% +our lqr controllers +right and we turned it into the hbj + + align:start position:0% +right and we turned it into the hbj + + + align:start position:0% +right and we turned it into the hbj +and in the + + align:start position:0% +and in the + + + align:start position:0% +and in the +finite time case we didn't even turn it + + align:start position:0% +finite time case we didn't even turn it + + + align:start position:0% +finite time case we didn't even turn it +into the hbj we just started we started + + align:start position:0% +into the hbj we just started we started + + + align:start position:0% +into the hbj we just started we started +we can back this out with dynamic + + align:start position:0% +we can back this out with dynamic + + + align:start position:0% +we can back this out with dynamic +programming okay + + align:start position:0% +programming okay + + + align:start position:0% +programming okay +so we can actually use the same thing to + + align:start position:0% +so we can actually use the same thing to + + + align:start position:0% +so we can actually use the same thing to +analytically try to to design some + + align:start position:0% +analytically try to to design some + + + align:start position:0% +analytically try to to design some +controllers + + align:start position:0% +controllers + + + align:start position:0% +controllers +for stochastic optimal control cases + + align:start position:0% +for stochastic optimal control cases + + + align:start position:0% +for stochastic optimal control cases +and just like in the in the + + align:start position:0% +and just like in the in the + + + align:start position:0% +and just like in the in the +deterministic case there's one sort of + + align:start position:0% +deterministic case there's one sort of + + + align:start position:0% +deterministic case there's one sort of +outstanding result that everybody knows + + align:start position:0% +outstanding result that everybody knows + + + align:start position:0% +outstanding result that everybody knows +and uses + + align:start position:0% +and uses + + + align:start position:0% +and uses +and that's the linear + + align:start position:0% +and that's the linear + + + align:start position:0% +and that's the linear +quadratic regulator + + align:start position:0% +quadratic regulator + + + align:start position:0% +quadratic regulator +with gaussian noise + + align:start position:0% +with gaussian noise + + + align:start position:0% +with gaussian noise +right + + align:start position:0% + + + + align:start position:0% + +lqg + + align:start position:0% +lqg + + + align:start position:0% +lqg +that's the shorthand + + align:start position:0% + + + + align:start position:0% + +there's two forms of it one of them is + + align:start position:0% +there's two forms of it one of them is + + + align:start position:0% +there's two forms of it one of them is +noise gaussian noise also on the sensors + + align:start position:0% +noise gaussian noise also on the sensors + + + align:start position:0% +noise gaussian noise also on the sensors +but let's just worry about the case + + align:start position:0% +but let's just worry about the case + + + align:start position:0% +but let's just worry about the case +where + + align:start position:0% +where + + + align:start position:0% +where +we know there's there's no uncertainty + + align:start position:0% +we know there's there's no uncertainty + + + align:start position:0% +we know there's there's no uncertainty +in the sensor is only the dynamic noise + + align:start position:0% +in the sensor is only the dynamic noise + + + align:start position:0% +in the sensor is only the dynamic noise +so + + align:start position:0% + + + + align:start position:0% + +x n plus one + + align:start position:0% +x n plus one + + + align:start position:0% +x n plus one +is a it could be a of n it could be time + + align:start position:0% +is a it could be a of n it could be time + + + align:start position:0% +is a it could be a of n it could be time +varying or not + + align:start position:0% +varying or not + + + align:start position:0% +varying or not +x n + + align:start position:0% +x n + + + align:start position:0% +x n +plus b + + align:start position:0% +plus b + + + align:start position:0% +plus b +n u of n + + align:start position:0% +n u of n + + + align:start position:0% +n u of n +plus w n + + align:start position:0% + + + + align:start position:0% + +cost function again is the quadratic + + align:start position:0% +cost function again is the quadratic + + + align:start position:0% +cost function again is the quadratic +regulator + + align:start position:0% + + + + align:start position:0% + +what do you think is going to happen + + align:start position:0% +what do you think is going to happen + + + align:start position:0% +what do you think is going to happen +with that + + align:start position:0% +with that + + + align:start position:0% +with that +problem + + align:start position:0% +problem + + + align:start position:0% +problem +someone who hasn't used it extensively + + align:start position:0% +someone who hasn't used it extensively + + + align:start position:0% +someone who hasn't used it extensively +in your work what is the what's going to + + align:start position:0% +in your work what is the what's going to + + + align:start position:0% +in your work what is the what's going to +change about our lqr solution + + align:start position:0% +change about our lqr solution + + + align:start position:0% +change about our lqr solution +think about stabilizing the pendulum or + + align:start position:0% +think about stabilizing the pendulum or + + + align:start position:0% +think about stabilizing the pendulum or +something okay let's say we're doing + + align:start position:0% +something okay let's say we're doing + + + align:start position:0% +something okay let's say we're doing +optimal control on the simple pendulum + + align:start position:0% +optimal control on the simple pendulum + + + align:start position:0% +optimal control on the simple pendulum +linearized around the top and now + + align:start position:0% +linearized around the top and now + + + align:start position:0% +linearized around the top and now +there's disturbances bouncing me around + + align:start position:0% +there's disturbances bouncing me around + + + align:start position:0% +there's disturbances bouncing me around +how would you act differently + + align:start position:0% +how would you act differently + + + align:start position:0% +how would you act differently +given + + align:start position:0% +given + + + align:start position:0% +given +some model of the disturbances + + align:start position:0% +some model of the disturbances + + + align:start position:0% +some model of the disturbances +in the linear case + + align:start position:0% + + + + align:start position:0% + +how would you act differently if you + + align:start position:0% +how would you act differently if you + + + align:start position:0% +how would you act differently if you +know that somebody's going to be bumping + + align:start position:0% +know that somebody's going to be bumping + + + align:start position:0% +know that somebody's going to be bumping +me around with a mean zero let's keep w + + align:start position:0% +me around with a mean zero let's keep w + + + align:start position:0% +me around with a mean zero let's keep w +mean zero + + align:start position:0% + + + + align:start position:0% + +how would you act differently + + align:start position:0% +how would you act differently + + + align:start position:0% +how would you act differently +if you're a simple pendulum + + align:start position:0% +if you're a simple pendulum + + + align:start position:0% +if you're a simple pendulum +around the top + + align:start position:0% + + + + align:start position:0% + +anybody else want to weigh in + + align:start position:0% + + + + align:start position:0% + +what's that + + align:start position:0% +what's that + + + align:start position:0% +what's that +you might increase your gain or + + align:start position:0% +you might increase your gain or + + + align:start position:0% +you might increase your gain or +something like that you think + + align:start position:0% +something like that you think + + + align:start position:0% +something like that you think +yeah it turns out you wouldn't act + + align:start position:0% +yeah it turns out you wouldn't act + + + align:start position:0% +yeah it turns out you wouldn't act +different + + align:start position:0% + + + + align:start position:0% + +it's one of the most surprising results + + align:start position:0% +it's one of the most surprising results + + + align:start position:0% +it's one of the most surprising results +i think of + + align:start position:0% +i think of + + + align:start position:0% +i think of +of stochastic optimal control + + align:start position:0% +of stochastic optimal control + + + align:start position:0% +of stochastic optimal control +it turns out + + align:start position:0% +it turns out + + + align:start position:0% +it turns out +that you're that you work it all out you + + align:start position:0% +that you're that you work it all out you + + + align:start position:0% +that you're that you work it all out you +put your costs like this it wouldn't you + + align:start position:0% +put your costs like this it wouldn't you + + + align:start position:0% +put your costs like this it wouldn't you +don't turn your gains up because of the + + align:start position:0% +don't turn your gains up because of the + + + align:start position:0% +don't turn your gains up because of the +disturbances or anything like that the + + align:start position:0% +disturbances or anything like that the + + + align:start position:0% +disturbances or anything like that the +optimal solution for the for the + + align:start position:0% +optimal solution for the for the + + + align:start position:0% +optimal solution for the for the +stochastic case is the same + + align:start position:0% +stochastic case is the same + + + align:start position:0% +stochastic case is the same +policy + + align:start position:0% +policy + + + align:start position:0% +policy +as the optimal solution for the + + align:start position:0% +as the optimal solution for the + + + align:start position:0% +as the optimal solution for the +deterministic case okay it's also true + + align:start position:0% +deterministic case okay it's also true + + + align:start position:0% +deterministic case okay it's also true +in continuous time + + align:start position:0% + + + + align:start position:0% + +our inverse b transpose + + align:start position:0% +our inverse b transpose + + + align:start position:0% +our inverse b transpose +s of n + + align:start position:0% +s of n + + + align:start position:0% +s of n +x + + align:start position:0% +x + + + align:start position:0% +x +yeah it's the same + + align:start position:0% +yeah it's the same + + + align:start position:0% +yeah it's the same +um + + align:start position:0% +um + + + align:start position:0% +um +b of n here + + align:start position:0% + + + + align:start position:0% + +did i write something funny + + align:start position:0% + + + + align:start position:0% + +did you know that that clock isn't + + align:start position:0% +did you know that that clock isn't + + + align:start position:0% +did you know that that clock isn't +moving + + align:start position:0% +moving + + + align:start position:0% +moving +no i didn't am i way off time + + align:start position:0% + + + + align:start position:0% + +okay thank you for telling me that i + + align:start position:0% +okay thank you for telling me that i + + + align:start position:0% +okay thank you for telling me that i +thought i had time + + align:start position:0% +thought i had time + + + align:start position:0% +thought i had time +nice + + align:start position:0% +nice + + + align:start position:0% +nice +is the s the same + + align:start position:0% +is the s the same + + + align:start position:0% +is the s the same +the s is the same too oh sorry sorry + + align:start position:0% +the s is the same too oh sorry sorry + + + align:start position:0% +the s is the same too oh sorry sorry +good + + align:start position:0% +good + + + align:start position:0% +good +the s i wrote here is the same + + align:start position:0% +the s i wrote here is the same + + + align:start position:0% +the s i wrote here is the same +okay + + align:start position:0% +okay + + + align:start position:0% +okay +that is the same s that you get from the + + align:start position:0% +that is the same s that you get from the + + + align:start position:0% +that is the same s that you get from the +roccati equation but the total cost is + + align:start position:0% +roccati equation but the total cost is + + + align:start position:0% +roccati equation but the total cost is +bigger + + align:start position:0% +bigger + + + align:start position:0% +bigger +in the um + + align:start position:0% +in the um + + + align:start position:0% +in the um +so the policy is the same but + + align:start position:0% +so the policy is the same but + + + align:start position:0% +so the policy is the same but +so how much time do i really have do i + + align:start position:0% +so how much time do i really have do i + + + align:start position:0% +so how much time do i really have do i +have negative time already or am i + + align:start position:0% +have negative time already or am i + + + align:start position:0% +have negative time already or am i +sorry okay + + align:start position:0% +sorry okay + + + align:start position:0% +sorry okay +but j of n + + align:start position:0% +but j of n + + + align:start position:0% +but j of n +i thought it was just very exciting + + align:start position:0% +i thought it was just very exciting + + + align:start position:0% +i thought it was just very exciting +um + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% +uh + + + align:start position:0% +uh +is is this this plus some expected value + + align:start position:0% +is is this this plus some expected value + + + align:start position:0% +is is this this plus some expected value +of the + + align:start position:0% +of the + + + align:start position:0% +of the +the noise + + align:start position:0% + + + + align:start position:0% + +i was going to keep going for a long + + align:start position:0% +i was going to keep going for a long + + + align:start position:0% +i was going to keep going for a long +time probably + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so it's the same s that you had before + + align:start position:0% +so it's the same s that you had before + + + align:start position:0% +so it's the same s that you had before +but the cost to go that you get is + + align:start position:0% +but the cost to go that you get is + + + align:start position:0% +but the cost to go that you get is +actually higher + + align:start position:0% +actually higher + + + align:start position:0% +actually higher +like as in a way that you might expect + + align:start position:0% +like as in a way that you might expect + + + align:start position:0% +like as in a way that you might expect +with it actually depends on the cost on + + align:start position:0% +with it actually depends on the cost on + + + align:start position:0% +with it actually depends on the cost on +the other s and so the s n comes from + + align:start position:0% +the other s and so the s n comes from + + + align:start position:0% +the other s and so the s n comes from +the deterministic ricotta equation but + + align:start position:0% +the deterministic ricotta equation but + + + align:start position:0% +the deterministic ricotta equation but +the cost to go gets bigger + + align:start position:0% + + + + align:start position:0% + +yeah so that's one of the most + + align:start position:0% +yeah so that's one of the most + + + align:start position:0% +yeah so that's one of the most +surprising i think results from + + align:start position:0% +surprising i think results from + + + align:start position:0% +surprising i think results from +stochastic optimal control is that + + align:start position:0% +stochastic optimal control is that + + + align:start position:0% +stochastic optimal control is that +in one case it tells you it's okay to do + + align:start position:0% +in one case it tells you it's okay to do + + + align:start position:0% +in one case it tells you it's okay to do +deterministic optimal control yeah + + align:start position:0% +deterministic optimal control yeah + + + align:start position:0% +deterministic optimal control yeah +in most cases it's not okay it won't + + align:start position:0% +in most cases it's not okay it won't + + + align:start position:0% +in most cases it's not okay it won't +give you the same thing \ No newline at end of file diff --git a/KoXTTlI7mIg.txt b/KoXTTlI7mIg.txt new file mode 100644 index 0000000000000000000000000000000000000000..8140a69e4ff5b06c92c18a4960fd6bbea4915272 --- /dev/null +++ b/KoXTTlI7mIg.txt @@ -0,0 +1,243 @@ +align:start position:0% + +so in Italy we study a lot we do a lot + + align:start position:0% +so in Italy we study a lot we do a lot + + + align:start position:0% +so in Italy we study a lot we do a lot +of grammar and um logic uh structure of + + align:start position:0% +of grammar and um logic uh structure of + + + align:start position:0% +of grammar and um logic uh structure of +the sentence we study that a lot and we + + align:start position:0% +the sentence we study that a lot and we + + + align:start position:0% +the sentence we study that a lot and we +also study Latin so I'm used to think of + + align:start position:0% +also study Latin so I'm used to think of + + + align:start position:0% +also study Latin so I'm used to think of +um the language in terms of the + + align:start position:0% +um the language in terms of the + + + align:start position:0% +um the language in terms of the +different uh components and I noticed + + align:start position:0% +different uh components and I noticed + + + align:start position:0% +different uh components and I noticed +that maybe that's not so common among uh + + align:start position:0% +that maybe that's not so common among uh + + + align:start position:0% +that maybe that's not so common among uh +students here uh among American or + + align:start position:0% +students here uh among American or + + + align:start position:0% +students here uh among American or +International students + + align:start position:0% +International students + + + align:start position:0% +International students +um so that was a little bit of a + + align:start position:0% +um so that was a little bit of a + + + align:start position:0% +um so that was a little bit of a +challenge to help them to um to identify + + align:start position:0% +challenge to help them to um to identify + + + align:start position:0% +challenge to help them to um to identify +for example the different roles of a + + align:start position:0% +for example the different roles of a + + + align:start position:0% +for example the different roles of a +word in a sentence because in the + + align:start position:0% +word in a sentence because in the + + + align:start position:0% +word in a sentence because in the +English language is not so important you + + align:start position:0% +English language is not so important you + + + align:start position:0% +English language is not so important you +don't have you don't conjugate you don't + + align:start position:0% +don't have you don't conjugate you don't + + + align:start position:0% +don't have you don't conjugate you don't +change the endings of the adjectives + + align:start position:0% +change the endings of the adjectives + + + align:start position:0% +change the endings of the adjectives +while in Italian that makes a big + + align:start position:0% +while in Italian that makes a big + + + align:start position:0% +while in Italian that makes a big +difference so I needed to really help + + align:start position:0% +difference so I needed to really help + + + align:start position:0% +difference so I needed to really help +the students to + + align:start position:0% +the students to + + + align:start position:0% +the students to +identify the this part the structure of + + align:start position:0% +identify the this part the structure of + + + align:start position:0% +identify the this part the structure of +of the phrases that was maybe a little + + align:start position:0% +of the phrases that was maybe a little + + + align:start position:0% +of the phrases that was maybe a little +bit of a challenge but it was I expected + + align:start position:0% +bit of a challenge but it was I expected + + + align:start position:0% +bit of a challenge but it was I expected +it and also I had a few students who had + + align:start position:0% +it and also I had a few students who had + + + align:start position:0% +it and also I had a few students who had +learned Spanish before and it's very + + align:start position:0% +learned Spanish before and it's very + + + align:start position:0% +learned Spanish before and it's very +since well Italian and Spanish have the + + align:start position:0% +since well Italian and Spanish have the + + + align:start position:0% +since well Italian and Spanish have the +same origin then um I think for them the + + align:start position:0% +same origin then um I think for them the + + + align:start position:0% +same origin then um I think for them the +Big Challenge was to make the + + align:start position:0% +Big Challenge was to make the + + + align:start position:0% +Big Challenge was to make the +distinction between the two so it was + + align:start position:0% +distinction between the two so it was + + + align:start position:0% +distinction between the two so it was +easier in a sense to pick up but then um + + align:start position:0% +easier in a sense to pick up but then um + + + align:start position:0% +easier in a sense to pick up but then um +they had struggled a little to make the + + align:start position:0% +they had struggled a little to make the + + + align:start position:0% +they had struggled a little to make the +distinction to make a difference \ No newline at end of file diff --git a/LIDBqUPxNys.txt b/LIDBqUPxNys.txt new file mode 100644 index 0000000000000000000000000000000000000000..75283a058a8d271a1f77e38070550ee9c0df16f9 --- /dev/null +++ b/LIDBqUPxNys.txt @@ -0,0 +1,14928 @@ +align:start position:0% + +doing right now is uh hopefully you're + + align:start position:0% +doing right now is uh hopefully you're + + + align:start position:0% +doing right now is uh hopefully you're +all reading uh chapter six on which + + align:start position:0% +all reading uh chapter six on which + + + align:start position:0% +all reading uh chapter six on which +covers the process of thermal + + align:start position:0% +covers the process of thermal + + + align:start position:0% +covers the process of thermal +oxidation last time we talked about uh + + align:start position:0% +oxidation last time we talked about uh + + + align:start position:0% +oxidation last time we talked about uh +General introduction to Thermal oxides + + align:start position:0% +General introduction to Thermal oxides + + + align:start position:0% +General introduction to Thermal oxides +in Silicon + + align:start position:0% +in Silicon + + + align:start position:0% +in Silicon +seamoss and uh we also talked about the + + align:start position:0% +seamoss and uh we also talked about the + + + align:start position:0% +seamoss and uh we also talked about the +metal oxide silicon or semiconductor + + align:start position:0% +metal oxide silicon or semiconductor + + + align:start position:0% +metal oxide silicon or semiconductor +capacitor and how uh electrical simple + + align:start position:0% +capacitor and how uh electrical simple + + + align:start position:0% +capacitor and how uh electrical simple +CV measurements can be used to + + align:start position:0% +CV measurements can be used to + + + align:start position:0% +CV measurements can be used to +understand the quality of the oxide and + + align:start position:0% +understand the quality of the oxide and + + + align:start position:0% +understand the quality of the oxide and +the charges that exist in that + + align:start position:0% +the charges that exist in that + + + align:start position:0% +the charges that exist in that +structure this time we're going to cover + + align:start position:0% +structure this time we're going to cover + + + align:start position:0% +structure this time we're going to cover +um a basic model called the deal Grove + + align:start position:0% +um a basic model called the deal Grove + + + align:start position:0% +um a basic model called the deal Grove +this is after the two people that's + + align:start position:0% +this is after the two people that's + + + align:start position:0% +this is after the two people that's +Bruce deal and Andy Grove um who came up + + align:start position:0% +Bruce deal and Andy Grove um who came up + + + align:start position:0% +Bruce deal and Andy Grove um who came up +with this linear par parabolic oxidation + + align:start position:0% +with this linear par parabolic oxidation + + + align:start position:0% +with this linear par parabolic oxidation +model it it really Remains the basic + + align:start position:0% +model it it really Remains the basic + + + align:start position:0% +model it it really Remains the basic +model used today um and then we'll talk + + align:start position:0% +model used today um and then we'll talk + + + align:start position:0% +model used today um and then we'll talk +about examples on how to use it uh and + + align:start position:0% +about examples on how to use it uh and + + + align:start position:0% +about examples on how to use it uh and +we'll finish up with other models of + + align:start position:0% +we'll finish up with other models of + + + align:start position:0% +we'll finish up with other models of +planer oxidation that are very useful in + + align:start position:0% +planer oxidation that are very useful in + + + align:start position:0% +planer oxidation that are very useful in +the very thin oxide regime um so I'm + + align:start position:0% +the very thin oxide regime um so I'm + + + align:start position:0% +the very thin oxide regime um so I'm +just curious how many people here have + + align:start position:0% +just curious how many people here have + + + align:start position:0% +just curious how many people here have +known or not known but have heard about + + align:start position:0% +known or not known but have heard about + + + align:start position:0% +known or not known but have heard about +the uh the de cve uh oxidation + + align:start position:0% +the uh the de cve uh oxidation + + + align:start position:0% +the uh the de cve uh oxidation +model so about uh maybe a little less + + align:start position:0% +model so about uh maybe a little less + + + align:start position:0% +model so about uh maybe a little less +than half or so okay so that works + + align:start position:0% +than half or so okay so that works + + + align:start position:0% +than half or so okay so that works +reasonably well it is it's we go through + + align:start position:0% +reasonably well it is it's we go through + + + align:start position:0% +reasonably well it is it's we go through +it because it's the basic model and then + + align:start position:0% +it because it's the basic model and then + + + align:start position:0% +it because it's the basic model and then +everything after that a lot of things + + align:start position:0% +everything after that a lot of things + + + align:start position:0% +everything after that a lot of things +after that tend to be corrections to the + + align:start position:0% +after that tend to be corrections to the + + + align:start position:0% +after that tend to be corrections to the +deal grow uh model so let's go on to + + align:start position:0% +deal grow uh model so let's go on to + + + align:start position:0% +deal grow uh model so let's go on to +slide number two and that shows the + + align:start position:0% +slide number two and that shows the + + + align:start position:0% +slide number two and that shows the +basic um sort of schematic setup for how + + align:start position:0% +basic um sort of schematic setup for how + + + align:start position:0% +basic um sort of schematic setup for how +uh de and Grove derive their model what + + align:start position:0% +uh de and Grove derive their model what + + + align:start position:0% +uh de and Grove derive their model what +it shows you is sort of turned sideways + + align:start position:0% +it shows you is sort of turned sideways + + + align:start position:0% +it shows you is sort of turned sideways +is you have a gas stream here on the + + align:start position:0% +is you have a gas stream here on the + + + align:start position:0% +is you have a gas stream here on the +left that's on top of the wafer um there + + align:start position:0% +left that's on top of the wafer um there + + + align:start position:0% +left that's on top of the wafer um there +is um a thermal uh an oxide being grown + + align:start position:0% +is um a thermal uh an oxide being grown + + + align:start position:0% +is um a thermal uh an oxide being grown +here in this white region the silicon + + align:start position:0% +here in this white region the silicon + + + align:start position:0% +here in this white region the silicon +dioxide and the pink on the right shows + + align:start position:0% +dioxide and the pink on the right shows + + + align:start position:0% +dioxide and the pink on the right shows +it's meant to represent the Silicon + + align:start position:0% +it's meant to represent the Silicon + + + align:start position:0% +it's meant to represent the Silicon +wafer and just to give you an order of + + align:start position:0% +wafer and just to give you an order of + + + align:start position:0% +wafer and just to give you an order of +magnitude scale the Silicon wafer is + + align:start position:0% +magnitude scale the Silicon wafer is + + + align:start position:0% +magnitude scale the Silicon wafer is +thick of course it's hundreds of microns + + align:start position:0% +thick of course it's hundreds of microns + + + align:start position:0% +thick of course it's hundreds of microns +this oxide that we're talking about + + align:start position:0% +this oxide that we're talking about + + + align:start position:0% +this oxide that we're talking about +growing is on the order of 0.1 0.01 + + align:start position:0% +growing is on the order of 0.1 0.01 + + + align:start position:0% +growing is on the order of 0.1 0.01 +Micron being about 100 angstroms or 10 + + align:start position:0% +Micron being about 100 angstroms or 10 + + + align:start position:0% +Micron being about 100 angstroms or 10 +nanometers up to maybe a micron that + + align:start position:0% +nanometers up to maybe a micron that + + + align:start position:0% +nanometers up to maybe a micron that +would be the range of reasonable + + align:start position:0% +would be the range of reasonable + + + align:start position:0% +would be the range of reasonable +thicknesses of which you would grow once + + align:start position:0% +thicknesses of which you would grow once + + + align:start position:0% +thicknesses of which you would grow once +you start growing more than a micron we + + align:start position:0% +you start growing more than a micron we + + + align:start position:0% +you start growing more than a micron we +as you'll see today um if you want to + + align:start position:0% +as you'll see today um if you want to + + + align:start position:0% +as you'll see today um if you want to +grow one or two three microns by a + + align:start position:0% +grow one or two three microns by a + + + align:start position:0% +grow one or two three microns by a +thermal process it gets pretty darn slow + + align:start position:0% +thermal process it gets pretty darn slow + + + align:start position:0% +thermal process it gets pretty darn slow +uh the kinetics are such that it becomes + + align:start position:0% +uh the kinetics are such that it becomes + + + align:start position:0% +uh the kinetics are such that it becomes +really not very practical uh so you + + align:start position:0% +really not very practical uh so you + + + align:start position:0% +really not very practical uh so you +don't see too many people growing oxides + + align:start position:0% +don't see too many people growing oxides + + + align:start position:0% +don't see too many people growing oxides +that are that much thicker than than a + + align:start position:0% +that are that much thicker than than a + + + align:start position:0% +that are that much thicker than than a +couple of microns if they need oxides + + align:start position:0% +couple of microns if they need oxides + + + align:start position:0% +couple of microns if they need oxides +that thick they do a different process + + align:start position:0% +that thick they do a different process + + + align:start position:0% +that thick they do a different process +uh called chemical vapor + + align:start position:0% +uh called chemical vapor + + + align:start position:0% +uh called chemical vapor +deposition so the basic idea of this + + align:start position:0% +deposition so the basic idea of this + + + align:start position:0% +deposition so the basic idea of this +model though is we have a gas stream + + align:start position:0% +model though is we have a gas stream + + + align:start position:0% +model though is we have a gas stream +here and there's a concentration C subg + + align:start position:0% +here and there's a concentration C subg + + + align:start position:0% +here and there's a concentration C subg +of the oxidant let's say it's oxygen + + align:start position:0% +of the oxidant let's say it's oxygen + + + align:start position:0% +of the oxidant let's say it's oxygen +could be oxygen could be water vapor but + + align:start position:0% +could be oxygen could be water vapor but + + + align:start position:0% +could be oxygen could be water vapor but +there has some concentration in the main + + align:start position:0% +there has some concentration in the main + + + align:start position:0% +there has some concentration in the main +gas uh flow in the main gas stream as + + align:start position:0% +gas uh flow in the main gas stream as + + + align:start position:0% +gas uh flow in the main gas stream as +you get closer to the oxide surf to the + + align:start position:0% +you get closer to the oxide surf to the + + + align:start position:0% +you get closer to the oxide surf to the +surface of the wafer which has oxide on + + align:start position:0% +surface of the wafer which has oxide on + + + align:start position:0% +surface of the wafer which has oxide on +it it has some um concentration C Subs + + align:start position:0% +it it has some um concentration C Subs + + + align:start position:0% +it it has some um concentration C Subs +right at the surface of the wafer there + + align:start position:0% +right at the surface of the wafer there + + + align:start position:0% +right at the surface of the wafer there +may be some boundary layer or whatever + + align:start position:0% +may be some boundary layer or whatever + + + align:start position:0% +may be some boundary layer or whatever +that causes a gradient to cross here but + + align:start position:0% +that causes a gradient to cross here but + + + align:start position:0% +that causes a gradient to cross here but +right at the surface of the wafer it's + + align:start position:0% +right at the surface of the wafer it's + + + align:start position:0% +right at the surface of the wafer it's +at CS in the G but in the gas phas in + + align:start position:0% +at CS in the G but in the gas phas in + + + align:start position:0% +at CS in the G but in the gas phas in +the solid right inside at the very uh + + align:start position:0% +the solid right inside at the very uh + + + align:start position:0% +the solid right inside at the very uh +Sur surface in the solid oxide this + + align:start position:0% +Sur surface in the solid oxide this + + + align:start position:0% +Sur surface in the solid oxide this +oxidant has some concentration C subo + + align:start position:0% +oxidant has some concentration C subo + + + align:start position:0% +oxidant has some concentration C subo +right at the surface or or c0 if you + + align:start position:0% +right at the surface or or c0 if you + + + align:start position:0% +right at the surface or or c0 if you +would like um and then there is some + + align:start position:0% +would like um and then there is some + + + align:start position:0% +would like um and then there is some +gradient uh of the oxidant I say of the + + align:start position:0% +gradient uh of the oxidant I say of the + + + align:start position:0% +gradient uh of the oxidant I say of the +oxygen molecule there's a gradient + + align:start position:0% +oxygen molecule there's a gradient + + + align:start position:0% +oxygen molecule there's a gradient +throughout the oxide and at the + + align:start position:0% +throughout the oxide and at the + + + align:start position:0% +throughout the oxide and at the +interface it has C subi the ey standing + + align:start position:0% +interface it has C subi the ey standing + + + align:start position:0% +interface it has C subi the ey standing +for the interface it has that + + align:start position:0% +for the interface it has that + + + align:start position:0% +for the interface it has that +concentration um and the um the basic + + align:start position:0% +concentration um and the um the basic + + + align:start position:0% +concentration um and the um the basic +chemical reactions that are happening + + align:start position:0% +chemical reactions that are happening + + + align:start position:0% +chemical reactions that are happening +now at the interface not at the oxide + + align:start position:0% +now at the interface not at the oxide + + + align:start position:0% +now at the interface not at the oxide +surface are shown here silicon plus + + align:start position:0% +surface are shown here silicon plus + + + align:start position:0% +surface are shown here silicon plus +oxygen going to S2 or silicon plus + + align:start position:0% +oxygen going to S2 or silicon plus + + + align:start position:0% +oxygen going to S2 or silicon plus +moisture uh H2O going to + + align:start position:0% +moisture uh H2O going to + + + align:start position:0% +moisture uh H2O going to +sio2 there and they're in the uh + + align:start position:0% +sio2 there and they're in the uh + + + align:start position:0% +sio2 there and they're in the uh +equations that we're going to derive the + + align:start position:0% +equations that we're going to derive the + + + align:start position:0% +equations that we're going to derive the +simple model there are three fluxes + + align:start position:0% +simple model there are three fluxes + + + align:start position:0% +simple model there are three fluxes +involved there's a flux F1 of oxidant um + + align:start position:0% +involved there's a flux F1 of oxidant um + + + align:start position:0% +involved there's a flux F1 of oxidant um +that has to uh be transported in the gas + + align:start position:0% +that has to uh be transported in the gas + + + align:start position:0% +that has to uh be transported in the gas +phas from the uh major portion of the + + align:start position:0% +phas from the uh major portion of the + + + align:start position:0% +phas from the uh major portion of the +gas phase in the center of the tube to + + align:start position:0% +gas phase in the center of the tube to + + + align:start position:0% +gas phase in the center of the tube to +the surface of the wafer that's one flux + + align:start position:0% +the surface of the wafer that's one flux + + + align:start position:0% +the surface of the wafer that's one flux +there's a flux F2 in the oxide this is + + align:start position:0% +there's a flux F2 in the oxide this is + + + align:start position:0% +there's a flux F2 in the oxide this is +the uh diffusion of the oxidant through + + align:start position:0% +the uh diffusion of the oxidant through + + + align:start position:0% +the uh diffusion of the oxidant through +the oxide and there's a finally a flux + + align:start position:0% +the oxide and there's a finally a flux + + + align:start position:0% +the oxide and there's a finally a flux +uh F3 which is the what's happening + + align:start position:0% +uh F3 which is the what's happening + + + align:start position:0% +uh F3 which is the what's happening +right at the interface as the O oxygen + + align:start position:0% +right at the interface as the O oxygen + + + align:start position:0% +right at the interface as the O oxygen +is incorporated into the growing + + align:start position:0% +is incorporated into the growing + + + align:start position:0% +is incorporated into the growing +oxide so let's go on to slide three um + + align:start position:0% +oxide so let's go on to slide three um + + + align:start position:0% +oxide so let's go on to slide three um +again on the upper uh upper diagram is + + align:start position:0% +again on the upper uh upper diagram is + + + align:start position:0% +again on the upper uh upper diagram is +exactly what I just shown you I've just + + align:start position:0% +exactly what I just shown you I've just + + + align:start position:0% +exactly what I just shown you I've just +shown you um for those of you who have + + align:start position:0% +shown you um for those of you who have + + + align:start position:0% +shown you um for those of you who have +forgotten on the upper right I'm + + align:start position:0% +forgotten on the upper right I'm + + + align:start position:0% +forgotten on the upper right I'm +reminding you what the definition of + + align:start position:0% +reminding you what the definition of + + + align:start position:0% +reminding you what the definition of +flux is what is a flux it's the number + + align:start position:0% +flux is what is a flux it's the number + + + align:start position:0% +flux is what is a flux it's the number +of particles it doesn't have to be in + + align:start position:0% +of particles it doesn't have to be in + + + align:start position:0% +of particles it doesn't have to be in +this case I'm talking about oxygen + + align:start position:0% +this case I'm talking about oxygen + + + align:start position:0% +this case I'm talking about oxygen +molecules or water vapor molec + + align:start position:0% +molecules or water vapor molec + + + align:start position:0% +molecules or water vapor molec +but it's the number of particles + + align:start position:0% +but it's the number of particles + + + align:start position:0% +but it's the number of particles +crossing a unit area so a unit area of + + align:start position:0% +crossing a unit area so a unit area of + + + align:start position:0% +crossing a unit area so a unit area of +in this in this direction here um per + + align:start position:0% +in this in this direction here um per + + + align:start position:0% +in this in this direction here um per +unit time so there's a flux uh in this + + align:start position:0% +unit time so there's a flux uh in this + + + align:start position:0% +unit time so there's a flux uh in this +case going from the left to the right in + + align:start position:0% +case going from the left to the right in + + + align:start position:0% +case going from the left to the right in +fact there's three different of them so + + align:start position:0% +fact there's three different of them so + + + align:start position:0% +fact there's three different of them so +uh what deal and Grove did was write + + align:start position:0% +uh what deal and Grove did was write + + + align:start position:0% +uh what deal and Grove did was write +down three very simple equations uh + + align:start position:0% +down three very simple equations uh + + + align:start position:0% +down three very simple equations uh +first order of flux equations which show + + align:start position:0% +first order of flux equations which show + + + align:start position:0% +first order of flux equations which show +these three these three um series parts + + align:start position:0% +these three these three um series parts + + + align:start position:0% +these three these three um series parts +of the process again they're all + + align:start position:0% +of the process again they're all + + + align:start position:0% +of the process again they're all +happening in series so there's a flux F1 + + align:start position:0% +happening in series so there's a flux F1 + + + align:start position:0% +happening in series so there's a flux F1 +they wrote down using Henry's law so + + align:start position:0% +they wrote down using Henry's law so + + + align:start position:0% +they wrote down using Henry's law so +Henry's law just says in the gas-based + + align:start position:0% +Henry's law just says in the gas-based + + + align:start position:0% +Henry's law just says in the gas-based +transport if you have um a concentration + + align:start position:0% +transport if you have um a concentration + + + align:start position:0% +transport if you have um a concentration +a difference or a gradient here from + + align:start position:0% +a difference or a gradient here from + + + align:start position:0% +a difference or a gradient here from +from this point here in the center of + + align:start position:0% +from this point here in the center of + + + align:start position:0% +from this point here in the center of +where the gas flow is to the surface C + + align:start position:0% +where the gas flow is to the surface C + + + align:start position:0% +where the gas flow is to the surface C +Subs that in in uh that the you can + + align:start position:0% +Subs that in in uh that the you can + + + align:start position:0% +Subs that in in uh that the you can +write the flux as just some constant + + align:start position:0% +write the flux as just some constant + + + align:start position:0% +write the flux as just some constant +some a Henry's constant uh a constant + + align:start position:0% +some a Henry's constant uh a constant + + + align:start position:0% +some a Henry's constant uh a constant +number uh times the difference in the + + align:start position:0% +number uh times the difference in the + + + align:start position:0% +number uh times the difference in the +concentration between the Surface and + + align:start position:0% +concentration between the Surface and + + + align:start position:0% +concentration between the Surface and +the center of the G and and where the + + align:start position:0% +the center of the G and and where the + + + align:start position:0% +the center of the G and and where the +the the concentration is CG so that's a + + align:start position:0% +the the concentration is CG so that's a + + + align:start position:0% +the the concentration is CG so that's a +simple equation from Henry's law uh a + + align:start position:0% +simple equation from Henry's law uh a + + + align:start position:0% +simple equation from Henry's law uh a +second equation they wrote down was + + align:start position:0% +second equation they wrote down was + + + align:start position:0% +second equation they wrote down was +diffusion through the oxide and this + + align:start position:0% +diffusion through the oxide and this + + + align:start position:0% +diffusion through the oxide and this +comes from fix law fix first law + + align:start position:0% +comes from fix law fix first law + + + align:start position:0% +comes from fix law fix first law +hopefully some of you have seen this + + align:start position:0% +hopefully some of you have seen this + + + align:start position:0% +hopefully some of you have seen this +maybe not in this particular form when + + align:start position:0% +maybe not in this particular form when + + + align:start position:0% +maybe not in this particular form when +we talk about diffusion it'll become + + align:start position:0% +we talk about diffusion it'll become + + + align:start position:0% +we talk about diffusion it'll become +very obvious uh um but this is the fixed + + align:start position:0% +very obvious uh um but this is the fixed + + + align:start position:0% +very obvious uh um but this is the fixed +first law for diffusion through the + + align:start position:0% +first law for diffusion through the + + + align:start position:0% +first law for diffusion through the +oxide the flux F2 is just a constant + + align:start position:0% +oxide the flux F2 is just a constant + + + align:start position:0% +oxide the flux F2 is just a constant +number which we call the diffusivity D + + align:start position:0% +number which we call the diffusivity D + + + align:start position:0% +number which we call the diffusivity D +times the gradient of the diffusant DN + + align:start position:0% +times the gradient of the diffusant DN + + + align:start position:0% +times the gradient of the diffusant DN +by DX so where n is generally just the + + align:start position:0% +by DX so where n is generally just the + + + align:start position:0% +by DX so where n is generally just the +concentration of whatever is diffusing + + align:start position:0% +concentration of whatever is diffusing + + + align:start position:0% +concentration of whatever is diffusing +uh um and you can write that if this is + + align:start position:0% +uh um and you can write that if this is + + + align:start position:0% +uh um and you can write that if this is +a straight line writing the the gradient + + align:start position:0% +a straight line writing the the gradient + + + align:start position:0% +a straight line writing the the gradient +of a straight line is very simple it's + + align:start position:0% +of a straight line is very simple it's + + + align:start position:0% +of a straight line is very simple it's +just C at the surface Co minus C + + align:start position:0% +just C at the surface Co minus C + + + align:start position:0% +just C at the surface Co minus C +interface divided by the thickness of + + align:start position:0% +interface divided by the thickness of + + + align:start position:0% +interface divided by the thickness of +the oxide so it's a simple uh simple + + align:start position:0% +the oxide so it's a simple uh simple + + + align:start position:0% +the oxide so it's a simple uh simple +equation to write diffusion through the + + align:start position:0% +equation to write diffusion through the + + + align:start position:0% +equation to write diffusion through the +oxide um and finally F3 is the flux at + + align:start position:0% +oxide um and finally F3 is the flux at + + + align:start position:0% +oxide um and finally F3 is the flux at +the interface and this is just a surface + + align:start position:0% +the interface and this is just a surface + + + align:start position:0% +the interface and this is just a surface +reaction rate so we write this final + + align:start position:0% +reaction rate so we write this final + + + align:start position:0% +reaction rate so we write this final +flux as case Subs a constant which has + + align:start position:0% +flux as case Subs a constant which has + + + align:start position:0% +flux as case Subs a constant which has +to do with how rapidly the the reaction + + align:start position:0% +to do with how rapidly the the reaction + + + align:start position:0% +to do with how rapidly the the reaction +is taking place at the interface times + + align:start position:0% +is taking place at the interface times + + + align:start position:0% +is taking place at the interface times +the concentration of oxygen or water + + align:start position:0% +the concentration of oxygen or water + + + align:start position:0% +the concentration of oxygen or water +vapor right at the interface so three + + align:start position:0% +vapor right at the interface so three + + + align:start position:0% +vapor right at the interface so three +equations uh for each of these + + align:start position:0% + + + + align:start position:0% + +fluxes so we go on to slide three now + + align:start position:0% +fluxes so we go on to slide three now + + + align:start position:0% +fluxes so we go on to slide three now +what what they're assuming is steady + + align:start position:0% +what what they're assuming is steady + + + align:start position:0% +what what they're assuming is steady +state condition and what we mean by + + align:start position:0% +state condition and what we mean by + + + align:start position:0% +state condition and what we mean by +steady state is um things are not + + align:start position:0% +steady state is um things are not + + + align:start position:0% +steady state is um things are not +changing with time uh these profiles so + + align:start position:0% +changing with time uh these profiles so + + + align:start position:0% +changing with time uh these profiles so +if I just go back one second to uh slide + + align:start position:0% +if I just go back one second to uh slide + + + align:start position:0% +if I just go back one second to uh slide +three is that this profile is there's no + + align:start position:0% +three is that this profile is there's no + + + align:start position:0% +three is that this profile is there's no +we're not in the transient phase this + + align:start position:0% +we're not in the transient phase this + + + align:start position:0% +we're not in the transient phase this +profile has now been established as a + + align:start position:0% +profile has now been established as a + + + align:start position:0% +profile has now been established as a +linear profile and a steady state it's + + align:start position:0% +linear profile and a steady state it's + + + align:start position:0% +linear profile and a steady state it's +it's not changing uh with with time + + align:start position:0% +it's not changing uh with with time + + + align:start position:0% +it's not changing uh with with time +there's you've established a constant + + align:start position:0% +there's you've established a constant + + + align:start position:0% +there's you've established a constant +profile so in those conditions then we + + align:start position:0% +profile so in those conditions then we + + + align:start position:0% +profile so in those conditions then we +can write down that the three fluxes in + + align:start position:0% +can write down that the three fluxes in + + + align:start position:0% +can write down that the three fluxes in +series are all equal to each other we + + align:start position:0% +series are all equal to each other we + + + align:start position:0% +series are all equal to each other we +don't have any buildup or any uh um or + + align:start position:0% +don't have any buildup or any uh um or + + + align:start position:0% +don't have any buildup or any uh um or +any sinks so F1 the flux throwing + + align:start position:0% +any sinks so F1 the flux throwing + + + align:start position:0% +any sinks so F1 the flux throwing +through the gas has to be equal to F2 + + align:start position:0% +through the gas has to be equal to F2 + + + align:start position:0% +through the gas has to be equal to F2 +the flux diffusing through has to be + + align:start position:0% +the flux diffusing through has to be + + + align:start position:0% +the flux diffusing through has to be +equal to the reactive flux um so uh in + + align:start position:0% +equal to the reactive flux um so uh in + + + align:start position:0% +equal to the reactive flux um so uh in +that case then it's relatively simple if + + align:start position:0% +that case then it's relatively simple if + + + align:start position:0% +that case then it's relatively simple if +you sit down and you equate those three + + align:start position:0% +you sit down and you equate those three + + + align:start position:0% +you sit down and you equate those three +equations you can derive this formula + + align:start position:0% +equations you can derive this formula + + + align:start position:0% +equations you can derive this formula +here uh equation number four for con the + + align:start position:0% +here uh equation number four for con the + + + align:start position:0% +here uh equation number four for con the +concentration of the oxygen molecules of + + align:start position:0% +concentration of the oxygen molecules of + + + align:start position:0% +concentration of the oxygen molecules of +the water vapor C subi at the interface + + align:start position:0% +the water vapor C subi at the interface + + + align:start position:0% +the water vapor C subi at the interface +you can write it as some constant C star + + align:start position:0% +you can write it as some constant C star + + + align:start position:0% +you can write it as some constant C star +which we'll talk about where C star is + + align:start position:0% +which we'll talk about where C star is + + + align:start position:0% +which we'll talk about where C star is +the solubility of the oxidant um uh in + + align:start position:0% +the solubility of the oxidant um uh in + + + align:start position:0% +the solubility of the oxidant um uh in +the oxide divided by um a three term + + align:start position:0% +the oxide divided by um a three term + + + align:start position:0% +the oxide divided by um a three term +expression 1 plus the ratio of K sub s + + align:start position:0% +expression 1 plus the ratio of K sub s + + + align:start position:0% +expression 1 plus the ratio of K sub s +to H um so that tells us something about + + align:start position:0% +to H um so that tells us something about + + + align:start position:0% +to H um so that tells us something about +the ratio of the uh surface reaction + + align:start position:0% +the ratio of the uh surface reaction + + + align:start position:0% +the ratio of the uh surface reaction +coefficient to Henry's coefficient h + + align:start position:0% +coefficient to Henry's coefficient h + + + align:start position:0% +coefficient to Henry's coefficient h +plus Cas sub s XD X overd this is + + align:start position:0% +plus Cas sub s XD X overd this is + + + align:start position:0% +plus Cas sub s XD X overd this is +involving a diffusivity + + align:start position:0% +involving a diffusivity + + + align:start position:0% +involving a diffusivity +term uh and so what we are generally + + align:start position:0% +term uh and so what we are generally + + + align:start position:0% +term uh and so what we are generally +going to do in this if we we can + + align:start position:0% +going to do in this if we we can + + + align:start position:0% +going to do in this if we we can +actually simplify this equation by + + align:start position:0% +actually simplify this equation by + + + align:start position:0% +actually simplify this equation by +recognizing um that we're actually can + + align:start position:0% +recognizing um that we're actually can + + + align:start position:0% +recognizing um that we're actually can +neglect F1 the gas phase transport which + + align:start position:0% +neglect F1 the gas phase transport which + + + align:start position:0% +neglect F1 the gas phase transport which +is usually a very good approximation + + align:start position:0% +is usually a very good approximation + + + align:start position:0% +is usually a very good approximation +it's very fast so if I if I go back to + + align:start position:0% +it's very fast so if I if I go back to + + + align:start position:0% +it's very fast so if I if I go back to +this slide number three briefly this + + align:start position:0% +this slide number three briefly this + + + align:start position:0% +this slide number three briefly this +flux is this is happening much much + + align:start position:0% +flux is this is happening much much + + + align:start position:0% +flux is this is happening much much +faster than these two processes than the + + align:start position:0% +faster than these two processes than the + + + align:start position:0% +faster than these two processes than the +diffusion um through the solid or then + + align:start position:0% +diffusion um through the solid or then + + + align:start position:0% +diffusion um through the solid or then +or than the reaction as it happens to + + align:start position:0% +or than the reaction as it happens to + + + align:start position:0% +or than the reaction as it happens to +turn out in this case that won't always + + align:start position:0% +turn out in this case that won't always + + + align:start position:0% +turn out in this case that won't always +be the case for other processes when we + + align:start position:0% +be the case for other processes when we + + + align:start position:0% +be the case for other processes when we +talk about epitaxial growth or chemical + + align:start position:0% +talk about epitaxial growth or chemical + + + align:start position:0% +talk about epitaxial growth or chemical +vapor deposition uh It won't always be + + align:start position:0% +vapor deposition uh It won't always be + + + align:start position:0% +vapor deposition uh It won't always be +the case that you can ignore the + + align:start position:0% +the case that you can ignore the + + + align:start position:0% +the case that you can ignore the +gasphase transport but as it turns out + + align:start position:0% +gasphase transport but as it turns out + + + align:start position:0% +gasphase transport but as it turns out +the surface reaction is slow enough and + + align:start position:0% +the surface reaction is slow enough and + + + align:start position:0% +the surface reaction is slow enough and +the diffusion through the oxide is slow + + align:start position:0% +the diffusion through the oxide is slow + + + align:start position:0% +the diffusion through the oxide is slow +enough that it all that this that this + + align:start position:0% +enough that it all that this that this + + + align:start position:0% +enough that it all that this that this +is always very fast um and so we can the + + align:start position:0% +is always very fast um and so we can the + + + align:start position:0% +is always very fast um and so we can the +beautiful thing about oxidation is you + + align:start position:0% +beautiful thing about oxidation is you + + + align:start position:0% +beautiful thing about oxidation is you +can ignore gas phase transport and + + align:start position:0% +can ignore gas phase transport and + + + align:start position:0% +can ignore gas phase transport and +that's why you can design oxidation + + align:start position:0% +that's why you can design oxidation + + + align:start position:0% +that's why you can design oxidation +tubes to be very simple you just stand + + align:start position:0% +tubes to be very simple you just stand + + + align:start position:0% +tubes to be very simple you just stand +all the Wafers up and flow the oxygen + + align:start position:0% +all the Wafers up and flow the oxygen + + + align:start position:0% +all the Wafers up and flow the oxygen +through and you don't have to care about + + align:start position:0% +through and you don't have to care about + + + align:start position:0% +through and you don't have to care about +exactly how the gas flows when we talk + + align:start position:0% +exactly how the gas flows when we talk + + + align:start position:0% +exactly how the gas flows when we talk +about other processes uh like epaxial + + align:start position:0% +about other processes uh like epaxial + + + align:start position:0% +about other processes uh like epaxial +growth no such luxury by any means in + + align:start position:0% +growth no such luxury by any means in + + + align:start position:0% +growth no such luxury by any means in +that case this flux is extremely + + align:start position:0% +that case this flux is extremely + + + align:start position:0% +that case this flux is extremely +important and in fact it controls the + + align:start position:0% +important and in fact it controls the + + + align:start position:0% +important and in fact it controls the +process many times so but we're very + + align:start position:0% +process many times so but we're very + + + align:start position:0% +process many times so but we're very +lucky in oxide growth that these two + + align:start position:0% +lucky in oxide growth that these two + + + align:start position:0% +lucky in oxide growth that these two +processes F2 and F3 are slow so we could + + align:start position:0% +processes F2 and F3 are slow so we could + + + align:start position:0% +processes F2 and F3 are slow so we could +ignore + + align:start position:0% +ignore + + + align:start position:0% +ignore +F1 and that just ends up simplifying the + + align:start position:0% +F1 and that just ends up simplifying the + + + align:start position:0% +F1 and that just ends up simplifying the +equations to um a certain extent um and + + align:start position:0% +equations to um a certain extent um and + + + align:start position:0% +equations to um a certain extent um and +so by if I rearrange this um a little + + align:start position:0% +so by if I rearrange this um a little + + + align:start position:0% +so by if I rearrange this um a little +bit we we get equation uh number five + + align:start position:0% +bit we we get equation uh number five + + + align:start position:0% +bit we we get equation uh number five +here for the uh we're really interested + + align:start position:0% +here for the uh we're really interested + + + align:start position:0% +here for the uh we're really interested +in C subo here uh the concentration uh + + align:start position:0% +in C subo here uh the concentration uh + + + align:start position:0% +in C subo here uh the concentration uh +at the surface uh of the O + + align:start position:0% +at the surface uh of the O + + + align:start position:0% +at the surface uh of the O +oxidant so let me combine now this + + align:start position:0% +oxidant so let me combine now this + + + align:start position:0% +oxidant so let me combine now this +equation number four which tells me what + + align:start position:0% +equation number four which tells me what + + + align:start position:0% +equation number four which tells me what +the concentration of water or or oxygen + + align:start position:0% +the concentration of water or or oxygen + + + align:start position:0% +the concentration of water or or oxygen +is at the interface with um I'm going to + + align:start position:0% +is at the interface with um I'm going to + + + align:start position:0% +is at the interface with um I'm going to +combine this equation with equation + + align:start position:0% +combine this equation with equation + + + align:start position:0% +combine this equation with equation +three just going back again which just + + align:start position:0% +three just going back again which just + + + align:start position:0% +three just going back again which just +tells me the the uh surface reaction + + align:start position:0% +tells me the the uh surface reaction + + + align:start position:0% +tells me the the uh surface reaction +rate + + align:start position:0% +rate + + + align:start position:0% +rate +flux uh and we get something like this + + align:start position:0% +flux uh and we get something like this + + + align:start position:0% +flux uh and we get something like this +that says it says that DX by DT so + + align:start position:0% +that says it says that DX by DT so + + + align:start position:0% +that says it says that DX by DT so +that's the rate of change of the + + align:start position:0% +that's the rate of change of the + + + align:start position:0% +that's the rate of change of the +thickness of the oxide DX by DT um we + + align:start position:0% +thickness of the oxide DX by DT um we + + + align:start position:0% +thickness of the oxide DX by DT um we +know we can write it as a flux divided + + align:start position:0% +know we can write it as a flux divided + + + align:start position:0% +know we can write it as a flux divided +by a concentration so N1 here is what + + align:start position:0% +by a concentration so N1 here is what + + + align:start position:0% +by a concentration so N1 here is what +anybody have an idea what N1 is just + + align:start position:0% +anybody have an idea what N1 is just + + + align:start position:0% +anybody have an idea what N1 is just +from dimensional + + align:start position:0% +from dimensional + + + align:start position:0% +from dimensional +arguments what kind of uh this is I I + + align:start position:0% +arguments what kind of uh this is I I + + + align:start position:0% +arguments what kind of uh this is I I +want to get DX by DT flux tells you the + + align:start position:0% +want to get DX by DT flux tells you the + + + align:start position:0% +want to get DX by DT flux tells you the +number of atoms per square + + align:start position:0% +number of atoms per square + + + align:start position:0% +number of atoms per square +centimeter per unit time so N1 has to + + align:start position:0% +centimeter per unit time so N1 has to + + + align:start position:0% +centimeter per unit time so N1 has to +have the units of the concentration per + + align:start position:0% +have the units of the concentration per + + + align:start position:0% +have the units of the concentration per +cubic centimeter basically um so so that + + align:start position:0% +cubic centimeter basically um so so that + + + align:start position:0% +cubic centimeter basically um so so that +it works out even just to work out + + align:start position:0% +it works out even just to work out + + + align:start position:0% +it works out even just to work out +dimensionally of course I don't have any + + align:start position:0% +dimensionally of course I don't have any + + + align:start position:0% +dimensionally of course I don't have any +chalk but that says what happens but if + + align:start position:0% +chalk but that says what happens but if + + + align:start position:0% +chalk but that says what happens but if +you work it out dimensionally flux has + + align:start position:0% +you work it out dimensionally flux has + + + align:start position:0% +you work it out dimensionally flux has +number of atoms per unit time per square + + align:start position:0% +number of atoms per unit time per square + + + align:start position:0% +number of atoms per unit time per square +centimeter this is the number of atoms + + align:start position:0% +centimeter this is the number of atoms + + + align:start position:0% +centimeter this is the number of atoms +in the oxide per cubic centimeter you + + align:start position:0% +in the oxide per cubic centimeter you + + + align:start position:0% +in the oxide per cubic centimeter you +end up with something like looks like + + align:start position:0% +end up with something like looks like + + + align:start position:0% +end up with something like looks like +cim per unit time or length per unit + + align:start position:0% +cim per unit time or length per unit + + + align:start position:0% +cim per unit time or length per unit +time so this is this is how uh quickly + + align:start position:0% +time so this is this is how uh quickly + + + align:start position:0% +time so this is this is how uh quickly +the oxide is growing the growth rate or + + align:start position:0% +the oxide is growing the growth rate or + + + align:start position:0% +the oxide is growing the growth rate or +the velocity which is what we're + + align:start position:0% +the velocity which is what we're + + + align:start position:0% +the velocity which is what we're +interested in the growth rate can be + + align:start position:0% +interested in the growth rate can be + + + align:start position:0% +interested in the growth rate can be +written uh like this it's the product of + + align:start position:0% +written uh like this it's the product of + + + align:start position:0% +written uh like this it's the product of +K Subs the surface reaction rate times + + align:start position:0% +K Subs the surface reaction rate times + + + align:start position:0% +K Subs the surface reaction rate times +the the C star C star is a solubility of + + align:start position:0% +the the C star C star is a solubility of + + + align:start position:0% +the the C star C star is a solubility of +the oxidant in the oxide so that's as + + align:start position:0% +the oxidant in the oxide so that's as + + + align:start position:0% +the oxidant in the oxide so that's as +much as as you can as you can put in at + + align:start position:0% +much as as you can as you can put in at + + + align:start position:0% +much as as you can as you can put in at +that temperature okay you might have + + align:start position:0% +that temperature okay you might have + + + align:start position:0% +that temperature okay you might have +more in the gas phase than that but + + align:start position:0% +more in the gas phase than that but + + + align:start position:0% +more in the gas phase than that but +that's how much will go in at that + + align:start position:0% +that's how much will go in at that + + + align:start position:0% +that's how much will go in at that +temperature C star divided by this + + align:start position:0% +temperature C star divided by this + + + align:start position:0% +temperature C star divided by this +denominator 1 plus K Subs over h plus K + + align:start position:0% +denominator 1 plus K Subs over h plus K + + + align:start position:0% +denominator 1 plus K Subs over h plus K +Subs x x over D so that's what that's + + align:start position:0% +Subs x x over D so that's what that's + + + align:start position:0% +Subs x x over D so that's what that's +telling us um the rate of growth of the + + align:start position:0% +telling us um the rate of growth of the + + + align:start position:0% +telling us um the rate of growth of the +oxide now we have it in terms of certain + + align:start position:0% +oxide now we have it in terms of certain + + + align:start position:0% +oxide now we have it in terms of certain +fundamental uh physical + + align:start position:0% +fundamental uh physical + + + align:start position:0% +fundamental uh physical +parameters so let's go on to um Slide + + align:start position:0% +parameters so let's go on to um Slide + + + align:start position:0% +parameters so let's go on to um Slide +Five we take that that was a simple + + align:start position:0% +Five we take that that was a simple + + + align:start position:0% +Five we take that that was a simple +if you want differential equation DX by + + align:start position:0% +if you want differential equation DX by + + + align:start position:0% +if you want differential equation DX by +DT just says you how rapidly it's uh the + + align:start position:0% +DT just says you how rapidly it's uh the + + + align:start position:0% +DT just says you how rapidly it's uh the +what is the velocity of of the growth + + align:start position:0% +what is the velocity of of the growth + + + align:start position:0% +what is the velocity of of the growth +and we integrate that if you look in the + + align:start position:0% +and we integrate that if you look in the + + + align:start position:0% +and we integrate that if you look in the +text it has some uh uh little bit of + + align:start position:0% +text it has some uh uh little bit of + + + align:start position:0% +text it has some uh uh little bit of +more detail on how you do the + + align:start position:0% +more detail on how you do the + + + align:start position:0% +more detail on how you do the +integration but you integrate it between + + align:start position:0% +integration but you integrate it between + + + align:start position:0% +integration but you integrate it between +zero and some time and between some + + align:start position:0% +zero and some time and between some + + + align:start position:0% +zero and some time and between some +initial + + align:start position:0% +initial + + + align:start position:0% +initial +thickness X subi and your final + + align:start position:0% +thickness X subi and your final + + + align:start position:0% +thickness X subi and your final +thickness or the thickness at any point + + align:start position:0% +thickness or the thickness at any point + + + align:start position:0% +thickness or the thickness at any point +in time x0 so here x0 is the thickness + + align:start position:0% +in time x0 so here x0 is the thickness + + + align:start position:0% +in time x0 so here x0 is the thickness +of the oxide right at the time t and XI + + align:start position:0% +of the oxide right at the time t and XI + + + align:start position:0% +of the oxide right at the time t and XI +is whatever thickness you started with + + align:start position:0% +is whatever thickness you started with + + + align:start position:0% +is whatever thickness you started with +could be zero whatever your thickness + + align:start position:0% +could be zero whatever your thickness + + + align:start position:0% +could be zero whatever your thickness +you started with at the the start of the + + align:start position:0% +you started with at the the start of the + + + align:start position:0% +you started with at the the start of the +oxidation process so by doing that + + align:start position:0% +oxidation process so by doing that + + + align:start position:0% +oxidation process so by doing that +integration you end up with that uh time + + align:start position:0% +integration you end up with that uh time + + + align:start position:0% +integration you end up with that uh time +if this is you can solve for time uh is + + align:start position:0% +if this is you can solve for time uh is + + + align:start position:0% +if this is you can solve for time uh is +equal to as a two- term expression + + align:start position:0% +equal to as a two- term expression + + + align:start position:0% +equal to as a two- term expression +something that involves x squared + + align:start position:0% +something that involves x squared + + + align:start position:0% +something that involves x squared +thickness squared and something that + + align:start position:0% +thickness squared and something that + + + align:start position:0% +thickness squared and something that +involves a linear term thickness to the + + align:start position:0% +involves a linear term thickness to the + + + align:start position:0% +involves a linear term thickness to the +F uh first power so this is the origin + + align:start position:0% +F uh first power so this is the origin + + + align:start position:0% +F uh first power so this is the origin +origin of this parabolic linear model + + align:start position:0% +origin of this parabolic linear model + + + align:start position:0% +origin of this parabolic linear model +here's a parabolic term it goes like the + + align:start position:0% +here's a parabolic term it goes like the + + + align:start position:0% +here's a parabolic term it goes like the +thickness squ here's a linear + + align:start position:0% +thickness squ here's a linear + + + align:start position:0% +thickness squ here's a linear +term and the uh multipliers are B here + + align:start position:0% +term and the uh multipliers are B here + + + align:start position:0% +term and the uh multipliers are B here +this is the multiplier um of the X not + + align:start position:0% +this is the multiplier um of the X not + + + align:start position:0% +this is the multiplier um of the X not +the parabolic term looks like this it's + + align:start position:0% +the parabolic term looks like this it's + + + align:start position:0% +the parabolic term looks like this it's +um it looks like the diffusion + + align:start position:0% +um it looks like the diffusion + + + align:start position:0% +um it looks like the diffusion +coefficient through the oxide times the + + align:start position:0% +coefficient through the oxide times the + + + align:start position:0% +coefficient through the oxide times the +solubility in the oxide C star divided + + align:start position:0% +solubility in the oxide C star divided + + + align:start position:0% +solubility in the oxide C star divided +by + + align:start position:0% +by + + + align:start position:0% +by +N1 so the parabolic process has to do + + align:start position:0% +N1 so the parabolic process has to do + + + align:start position:0% +N1 so the parabolic process has to do +with diffusion through the oxide the + + align:start position:0% +with diffusion through the oxide the + + + align:start position:0% +with diffusion through the oxide the +linear term the term that multiplies X + + align:start position:0% +linear term the term that multiplies X + + + align:start position:0% +linear term the term that multiplies X +notot um can be simplified here to um + + align:start position:0% +notot um can be simplified here to um + + + align:start position:0% +notot um can be simplified here to um +something that looks like C star KAS + + align:start position:0% +something that looks like C star KAS + + + align:start position:0% +something that looks like C star KAS +Subs over N1 and again I'm ignoring this + + align:start position:0% +Subs over N1 and again I'm ignoring this + + + align:start position:0% +Subs over N1 and again I'm ignoring this +one over H because um this is going very + + align:start position:0% +one over H because um this is going very + + + align:start position:0% +one over H because um this is going very +rapidly so H is very large compared to + + align:start position:0% +rapidly so H is very large compared to + + + align:start position:0% +rapidly so H is very large compared to +ques so I can ignore this + + align:start position:0% +ques so I can ignore this + + + align:start position:0% +ques so I can ignore this +term uh so this is the linear rate + + align:start position:0% +term uh so this is the linear rate + + + align:start position:0% +term uh so this is the linear rate +constant which go which tells you + + align:start position:0% +constant which go which tells you + + + align:start position:0% +constant which go which tells you +something about the surface reaction + + align:start position:0% +something about the surface reaction + + + align:start position:0% +something about the surface reaction +rate so linear rate constant has to do + + align:start position:0% +rate so linear rate constant has to do + + + align:start position:0% +rate so linear rate constant has to do +with a reaction parabolic has to do with + + align:start position:0% +with a reaction parabolic has to do with + + + align:start position:0% +with a reaction parabolic has to do with +a diffusion notice that they both depend + + align:start position:0% +a diffusion notice that they both depend + + + align:start position:0% +a diffusion notice that they both depend +however on C star which is the + + align:start position:0% +however on C star which is the + + + align:start position:0% +however on C star which is the +concentration or the solubility of + + align:start position:0% +concentration or the solubility of + + + align:start position:0% +concentration or the solubility of +either the oxygen or the water in the + + align:start position:0% +either the oxygen or the water in the + + + align:start position:0% +either the oxygen or the water in the +oxide + + align:start position:0% +oxide + + + align:start position:0% +oxide +let so let's go on to slide number six + + align:start position:0% +let so let's go on to slide number six + + + align:start position:0% +let so let's go on to slide number six +these rate constants B and B over a have + + align:start position:0% +these rate constants B and B over a have + + + align:start position:0% +these rate constants B and B over a have +some physical meaning we just talked + + align:start position:0% +some physical meaning we just talked + + + align:start position:0% +some physical meaning we just talked +about that diffusion uh of the oxidant + + align:start position:0% +about that diffusion uh of the oxidant + + + align:start position:0% +about that diffusion uh of the oxidant +and interface reaction and we write them + + align:start position:0% +and interface reaction and we write them + + + align:start position:0% +and interface reaction and we write them +uh we find experimentally that we can + + align:start position:0% +uh we find experimentally that we can + + + align:start position:0% +uh we find experimentally that we can +write them as arous relationships + + align:start position:0% +write them as arous relationships + + + align:start position:0% +write them as arous relationships +they're exponentially dependent on e to + + align:start position:0% +they're exponentially dependent on e to + + + align:start position:0% +they're exponentially dependent on e to +the some activation energy uh e the + + align:start position:0% +the some activation energy uh e the + + + align:start position:0% +the some activation energy uh e the +minus E1 over KT or E Theus E2 over KT + + align:start position:0% +minus E1 over KT or E Theus E2 over KT + + + align:start position:0% +minus E1 over KT or E Theus E2 over KT +times a + + align:start position:0% +times a + + + align:start position:0% +times a +prefactor uh the preactor here is C1 uh + + align:start position:0% +prefactor uh the preactor here is C1 uh + + + align:start position:0% +prefactor uh the preactor here is C1 uh +for B and B over a is + + align:start position:0% +for B and B over a is + + + align:start position:0% +for B and B over a is +C2 and these rate constants have been + + align:start position:0% +C2 and these rate constants have been + + + align:start position:0% +C2 and these rate constants have been +studied for many years people have + + align:start position:0% +studied for many years people have + + + align:start position:0% +studied for many years people have +measured them or tried to extract them + + align:start position:0% +measured them or tried to extract them + + + align:start position:0% +measured them or tried to extract them +uh experimentally and this is a chart um + + align:start position:0% +uh experimentally and this is a chart um + + + align:start position:0% +uh experimentally and this is a chart um +uh table I took directly out of your + + align:start position:0% +uh table I took directly out of your + + + align:start position:0% +uh table I took directly out of your +text which shows the ambient so that's + + align:start position:0% +text which shows the ambient so that's + + + align:start position:0% +text which shows the ambient so that's +the type of uh of uh uh gases + + align:start position:0% +the type of uh of uh uh gases + + + align:start position:0% +the type of uh of uh uh gases +environment that you are in the wafer is + + align:start position:0% +environment that you are in the wafer is + + + align:start position:0% +environment that you are in the wafer is +in and the rate constants B and B over a + + align:start position:0% +in and the rate constants B and B over a + + + align:start position:0% +in and the rate constants B and B over a +and how to calculate them so in dry + + align:start position:0% +and how to calculate them so in dry + + + align:start position:0% +and how to calculate them so in dry +oxygen so there's you're flowing O2 in + + align:start position:0% +oxygen so there's you're flowing O2 in + + + align:start position:0% +oxygen so there's you're flowing O2 in +the tube but there's no moisture around + + align:start position:0% +the tube but there's no moisture around + + + align:start position:0% +the tube but there's no moisture around +um to catch calculate the B rate + + align:start position:0% +um to catch calculate the B rate + + + align:start position:0% +um to catch calculate the B rate +constant you need to know C1 and you + + align:start position:0% +constant you need to know C1 and you + + + align:start position:0% +constant you need to know C1 and you +need to know E1 the activation energies + + align:start position:0% +need to know E1 the activation energies + + + align:start position:0% +need to know E1 the activation energies +uh wed O2 they're listed um uh so and + + align:start position:0% +uh wed O2 they're listed um uh so and + + + align:start position:0% +uh wed O2 they're listed um uh so and +and and the and H2O and moisture + + align:start position:0% +and and the and H2O and moisture + + + align:start position:0% +and and the and H2O and moisture +environment so these are by the way just + + align:start position:0% +environment so these are by the way just + + + align:start position:0% +environment so these are by the way just +be careful when you're going to use + + align:start position:0% +be careful when you're going to use + + + align:start position:0% +be careful when you're going to use +these numbers these are for 111 silicon + + align:start position:0% +these numbers these are for 111 silicon + + + align:start position:0% +these numbers these are for 111 silicon +oxidation so that's oxidation of a wafer + + align:start position:0% +oxidation so that's oxidation of a wafer + + + align:start position:0% +oxidation so that's oxidation of a wafer +with orientation surface of 111 at one + + align:start position:0% +with orientation surface of 111 at one + + + align:start position:0% +with orientation surface of 111 at one +atmospheric pressure if you want to know + + align:start position:0% +atmospheric pressure if you want to know + + + align:start position:0% +atmospheric pressure if you want to know +the values for one0 silicon then you + + align:start position:0% +the values for one0 silicon then you + + + align:start position:0% +the values for one0 silicon then you +take the C2 values these B over a the + + align:start position:0% +take the C2 values these B over a the + + + align:start position:0% +take the C2 values these B over a the +rate constants uh and you divide by 1.68 + + align:start position:0% +rate constants uh and you divide by 1.68 + + + align:start position:0% +rate constants uh and you divide by 1.68 +so it's slower for a one z0 interface + + align:start position:0% +so it's slower for a one z0 interface + + + align:start position:0% +so it's slower for a one z0 interface +and if we if you go back and look at + + align:start position:0% +and if we if you go back and look at + + + align:start position:0% +and if we if you go back and look at +your crystallography and look at the + + align:start position:0% +your crystallography and look at the + + + align:start position:0% +your crystallography and look at the +number of atoms per square centimeter it + + align:start position:0% +number of atoms per square centimeter it + + + align:start position:0% +number of atoms per square centimeter it +actually makes some sense because on a + + align:start position:0% +actually makes some sense because on a + + + align:start position:0% +actually makes some sense because on a +111 interface we have the largest number + + align:start position:0% +111 interface we have the largest number + + + align:start position:0% +111 interface we have the largest number +of atoms per square centimeter uh + + align:start position:0% +of atoms per square centimeter uh + + + align:start position:0% +of atoms per square centimeter uh +available uh uh so uh for the oxidation + + align:start position:0% +available uh uh so uh for the oxidation + + + align:start position:0% +available uh uh so uh for the oxidation +so it's going to be the rate constants + + align:start position:0% +so it's going to be the rate constants + + + align:start position:0% +so it's going to be the rate constants +are going to be faster uh but notice um + + align:start position:0% +are going to be faster uh but notice um + + + align:start position:0% +are going to be faster uh but notice um +the activation energy doesn't change uh + + align:start position:0% +the activation energy doesn't change uh + + + align:start position:0% +the activation energy doesn't change uh +as you change orientations it's all for + + align:start position:0% +as you change orientations it's all for + + + align:start position:0% +as you change orientations it's all for +the rate constant B over a the surface + + align:start position:0% +the rate constant B over a the surface + + + align:start position:0% +the rate constant B over a the surface +reaction rate um it all has an + + align:start position:0% +reaction rate um it all has an + + + align:start position:0% +reaction rate um it all has an +activation energy of close to two uh 2 + + align:start position:0% +activation energy of close to two uh 2 + + + align:start position:0% +activation energy of close to two uh 2 +EV uh so the activation energy for boa + + align:start position:0% +EV uh so the activation energy for boa + + + align:start position:0% +EV uh so the activation energy for boa +is roughly constant um it just depends + + align:start position:0% +is roughly constant um it just depends + + + align:start position:0% +is roughly constant um it just depends +on the surface reaction rate for B uh + + align:start position:0% +on the surface reaction rate for B uh + + + align:start position:0% +on the surface reaction rate for B uh +interestingly it uh the activation + + align:start position:0% +interestingly it uh the activation + + + align:start position:0% +interestingly it uh the activation +energy for B varies with the process so + + align:start position:0% +energy for B varies with the process so + + + align:start position:0% +energy for B varies with the process so +depending on whether you're in a dry O2 + + align:start position:0% +depending on whether you're in a dry O2 + + + align:start position:0% +depending on whether you're in a dry O2 +here um you get 1 23 uh EV here this is + + align:start position:0% +here um you get 1 23 uh EV here this is + + + align:start position:0% +here um you get 1 23 uh EV here this is +7 EV and for moisture and for water it's + + align:start position:0% +7 EV and for moisture and for water it's + + + align:start position:0% +7 EV and for moisture and for water it's +78 EV so it actually varies with the + + align:start position:0% +78 EV so it actually varies with the + + + align:start position:0% +78 EV so it actually varies with the +process and that makes some sense + + align:start position:0% +process and that makes some sense + + + align:start position:0% +process and that makes some sense +because what did we say B depends on + + align:start position:0% +because what did we say B depends on + + + align:start position:0% +because what did we say B depends on +depends on the diffusion of this species + + align:start position:0% +depends on the diffusion of this species + + + align:start position:0% +depends on the diffusion of this species +through the oxide well a water molecule + + align:start position:0% +through the oxide well a water molecule + + + align:start position:0% +through the oxide well a water molecule +if that's what's diffusing the oxide is + + align:start position:0% +if that's what's diffusing the oxide is + + + align:start position:0% +if that's what's diffusing the oxide is +going to diffuse at a different rate um + + align:start position:0% +going to diffuse at a different rate um + + + align:start position:0% +going to diffuse at a different rate um +or maybe have a different uh + + align:start position:0% +or maybe have a different uh + + + align:start position:0% +or maybe have a different uh +solubility uh than uh water than the um + + align:start position:0% +solubility uh than uh water than the um + + + align:start position:0% +solubility uh than uh water than the um +dry o than just oxygen molecule so we do + + align:start position:0% +dry o than just oxygen molecule so we do + + + align:start position:0% +dry o than just oxygen molecule so we do +see a difference um in the activation + + align:start position:0% +see a difference um in the activation + + + align:start position:0% +see a difference um in the activation +energy for + + align:start position:0% +energy for + + + align:start position:0% +energy for +B and on slide seven you could obviously + + align:start position:0% +B and on slide seven you could obviously + + + align:start position:0% +B and on slide seven you could obviously +you could do this yourself you just sit + + align:start position:0% +you could do this yourself you just sit + + + align:start position:0% +you could do this yourself you just sit +down with those equations and on a semi + + align:start position:0% +down with those equations and on a semi + + + align:start position:0% +down with those equations and on a semi +log plot so this is a log scale on the + + align:start position:0% +log plot so this is a log scale on the + + + align:start position:0% +log plot so this is a log scale on the +y- AIS and this is a one overt or a + + align:start position:0% +y- AIS and this is a one overt or a + + + align:start position:0% +y- AIS and this is a one overt or a +th000 overt this is a standard arenus + + align:start position:0% +th000 overt this is a standard arenus + + + align:start position:0% +th000 overt this is a standard arenus +plot uh that if you you have to make uh + + align:start position:0% +plot uh that if you you have to make uh + + + align:start position:0% +plot uh that if you you have to make uh +so um on a on a semi log plot uh any + + align:start position:0% +so um on a on a semi log plot uh any + + + align:start position:0% +so um on a on a semi log plot uh any +kind of exponential relationship will + + align:start position:0% +kind of exponential relationship will + + + align:start position:0% +kind of exponential relationship will +appear as a straight line right because + + align:start position:0% +appear as a straight line right because + + + align:start position:0% +appear as a straight line right because +it's log paper + + align:start position:0% +it's log paper + + + align:start position:0% +it's log paper +um and these are the different um + + align:start position:0% +um and these are the different um + + + align:start position:0% +um and these are the different um +constants here we are for a water is the + + align:start position:0% +constants here we are for a water is the + + + align:start position:0% +constants here we are for a water is the +B constant um and uh the uh B over a + + align:start position:0% +B constant um and uh the uh B over a + + + align:start position:0% +B constant um and uh the uh B over a +rather and this is the B constant and um + + align:start position:0% +rather and this is the B constant and um + + + align:start position:0% +rather and this is the B constant and um +these are taken these are for 111 so I + + align:start position:0% +these are taken these are for 111 so I + + + align:start position:0% +these are taken these are for 111 so I +just you just literally plot what values + + align:start position:0% +just you just literally plot what values + + + align:start position:0% +just you just literally plot what values +are on the table one thing you see right + + align:start position:0% +are on the table one thing you see right + + + align:start position:0% +are on the table one thing you see right +off the bat just from this plot these + + align:start position:0% +off the bat just from this plot these + + + align:start position:0% +off the bat just from this plot these +two lines on top that are faster that + + align:start position:0% +two lines on top that are faster that + + + align:start position:0% +two lines on top that are faster that +are larger are for uh oxidation in water + + align:start position:0% +are larger are for uh oxidation in water + + + align:start position:0% +are larger are for uh oxidation in water +vapor as opposed to dry so right off the + + align:start position:0% +vapor as opposed to dry so right off the + + + align:start position:0% +vapor as opposed to dry so right off the +bat you know the rate constants are + + align:start position:0% +bat you know the rate constants are + + + align:start position:0% +bat you know the rate constants are +higher for water than dry so if you want + + align:start position:0% +higher for water than dry so if you want + + + align:start position:0% +higher for water than dry so if you want +to grow faster an oxide you would grow + + align:start position:0% +to grow faster an oxide you would grow + + + align:start position:0% +to grow faster an oxide you would grow +it in a in a moisture environment not + + align:start position:0% +it in a in a moisture environment not + + + align:start position:0% +it in a in a moisture environment not +not in dry O2 and that's typically the + + align:start position:0% +not in dry O2 and that's typically the + + + align:start position:0% +not in dry O2 and that's typically the +case people grow thick oxides using a + + align:start position:0% +case people grow thick oxides using a + + + align:start position:0% +case people grow thick oxides using a +wet environment thin oxides using a dry + + align:start position:0% + + + + align:start position:0% + +environment okay let's go just uh go on + + align:start position:0% +environment okay let's go just uh go on + + + align:start position:0% +environment okay let's go just uh go on +to slide number eight and and just + + align:start position:0% +to slide number eight and and just + + + align:start position:0% +to slide number eight and and just +reformulate this you can do some + + align:start position:0% +reformulate this you can do some + + + align:start position:0% +reformulate this you can do some +mathematical manipulations on the law + + align:start position:0% +mathematical manipulations on the law + + + align:start position:0% +mathematical manipulations on the law +the linear parabolic law as I showed it + + align:start position:0% +the linear parabolic law as I showed it + + + align:start position:0% +the linear parabolic law as I showed it +earlier I've just repeated that equation + + align:start position:0% +earlier I've just repeated that equation + + + align:start position:0% +earlier I've just repeated that equation +where on the right hand side we've + + align:start position:0% +where on the right hand side we've + + + align:start position:0% +where on the right hand side we've +solved for T the left hand side is the + + align:start position:0% +solved for T the left hand side is the + + + align:start position:0% +solved for T the left hand side is the +oxide + + align:start position:0% +oxide + + + align:start position:0% +oxide +thickness um there are alternate ways to + + align:start position:0% +thickness um there are alternate ways to + + + align:start position:0% +thickness um there are alternate ways to +express this uh this law and and in fact + + align:start position:0% +express this uh this law and and in fact + + + align:start position:0% +express this uh this law and and in fact +here's a reformulation of it shown in + + align:start position:0% +here's a reformulation of it shown in + + + align:start position:0% +here's a reformulation of it shown in +the second um equation on this slide + + align:start position:0% +the second um equation on this slide + + + align:start position:0% +the second um equation on this slide +what you've seen is what we've done is + + align:start position:0% +what you've seen is what we've done is + + + align:start position:0% +what you've seen is what we've done is +now we've expressing it as x^2 over B + + align:start position:0% +now we've expressing it as x^2 over B + + + align:start position:0% +now we've expressing it as x^2 over B +plus xot / B over a is equal to t plus + + align:start position:0% +plus xot / B over a is equal to t plus + + + align:start position:0% +plus xot / B over a is equal to t plus +to where what we've done is to now is + + align:start position:0% +to where what we've done is to now is + + + align:start position:0% +to where what we've done is to now is +defined + + align:start position:0% +defined + + + align:start position:0% +defined +um as the time that it would have taken + + align:start position:0% +um as the time that it would have taken + + + align:start position:0% +um as the time that it would have taken +the effective time to grow the initial + + align:start position:0% +the effective time to grow the initial + + + align:start position:0% +the effective time to grow the initial +oxide thickness X subi so this is just + + align:start position:0% +oxide thickness X subi so this is just + + + align:start position:0% +oxide thickness X subi so this is just +obtained by mathematical manipulation of + + align:start position:0% +obtained by mathematical manipulation of + + + align:start position:0% +obtained by mathematical manipulation of +the first equation so if you set to + + align:start position:0% +the first equation so if you set to + + + align:start position:0% +the first equation so if you set to +equal to x i the initial squar plus a XI + + align:start position:0% +equal to x i the initial squar plus a XI + + + align:start position:0% +equal to x i the initial squar plus a XI +over B just mathematically you do that + + align:start position:0% +over B just mathematically you do that + + + align:start position:0% +over B just mathematically you do that +then you get a mathematical equence of + + align:start position:0% +then you get a mathematical equence of + + + align:start position:0% +then you get a mathematical equence of +this second equation to the first + + align:start position:0% +this second equation to the first + + + align:start position:0% +this second equation to the first +equation um sometimes you also want to + + align:start position:0% +equation um sometimes you also want to + + + align:start position:0% +equation um sometimes you also want to +explicitly have an equation that Sol + + align:start position:0% +explicitly have an equation that Sol + + + align:start position:0% +explicitly have an equation that Sol +that shows you what x knot is the oxide + + align:start position:0% +that shows you what x knot is the oxide + + + align:start position:0% +that shows you what x knot is the oxide +thickness that's not what's shown here + + align:start position:0% +thickness that's not what's shown here + + + align:start position:0% +thickness that's not what's shown here +on the upper two equations X knot is + + align:start position:0% +on the upper two equations X knot is + + + align:start position:0% +on the upper two equations X knot is +implicit because it appears here in two + + align:start position:0% +implicit because it appears here in two + + + align:start position:0% +implicit because it appears here in two +different terms if you want to solve + + align:start position:0% +different terms if you want to solve + + + align:start position:0% +different terms if you want to solve +explicitly for the oxide thickness you + + align:start position:0% +explicitly for the oxide thickness you + + + align:start position:0% +explicitly for the oxide thickness you +can see this middle equation x knot it + + align:start position:0% +can see this middle equation x knot it + + + align:start position:0% +can see this middle equation x knot it +looks like this it's got a square root + + align:start position:0% +looks like this it's got a square root + + + align:start position:0% +looks like this it's got a square root +uh dependence on time um and uh where + + align:start position:0% +uh dependence on time um and uh where + + + align:start position:0% +uh dependence on time um and uh where +again too has the same uh definition xi^ + + align:start position:0% +again too has the same uh definition xi^ + + + align:start position:0% +again too has the same uh definition xi^ +s just the time to grow the initial + + align:start position:0% +s just the time to grow the initial + + + align:start position:0% +s just the time to grow the initial +oxide the effect of time in the deal + + align:start position:0% +oxide the effect of time in the deal + + + align:start position:0% +oxide the effect of time in the deal +Grove model + + align:start position:0% + + + + align:start position:0% + +okay let's go on to slide number nine um + + align:start position:0% +okay let's go on to slide number nine um + + + align:start position:0% +okay let's go on to slide number nine um +and uh again this reformulation I I'm + + align:start position:0% +and uh again this reformulation I I'm + + + align:start position:0% +and uh again this reformulation I I'm +just repeating the equations from the + + align:start position:0% +just repeating the equations from the + + + align:start position:0% +just repeating the equations from the +previous slides so you don't have to + + align:start position:0% +previous slides so you don't have to + + + align:start position:0% +previous slides so you don't have to +remember them uh again XI and and to + + align:start position:0% +remember them uh again XI and and to + + + align:start position:0% +remember them uh again XI and and to +account for any oxide that was present + + align:start position:0% +account for any oxide that was present + + + align:start position:0% +account for any oxide that was present +at the start of the process okay we you + + align:start position:0% +at the start of the process okay we you + + + align:start position:0% +at the start of the process okay we you +know when you first push the wafer in + + align:start position:0% +know when you first push the wafer in + + + align:start position:0% +know when you first push the wafer in +you might have had other processes that + + align:start position:0% +you might have had other processes that + + + align:start position:0% +you might have had other processes that +have taken place and they might already + + align:start position:0% +have taken place and they might already + + + align:start position:0% +have taken place and they might already +have some oxide uh present there + + align:start position:0% +have some oxide uh present there + + + align:start position:0% +have some oxide uh present there +so we can take this uh we can take uh + + align:start position:0% +so we can take this uh we can take uh + + + align:start position:0% +so we can take this uh we can take uh +this equation and differentiate it and + + align:start position:0% +this equation and differentiate it and + + + align:start position:0% +this equation and differentiate it and +and let's say we're interest interested + + align:start position:0% +and let's say we're interest interested + + + align:start position:0% +and let's say we're interest interested +in the oxidation rate not the absolute + + align:start position:0% +in the oxidation rate not the absolute + + + align:start position:0% +in the oxidation rate not the absolute +thickness versus time but how is the + + align:start position:0% +thickness versus time but how is the + + + align:start position:0% +thickness versus time but how is the +rate changing how how fast is it + + align:start position:0% +rate changing how how fast is it + + + align:start position:0% +rate changing how how fast is it +growing um well this is this is the + + align:start position:0% +growing um well this is this is the + + + align:start position:0% +growing um well this is this is the +oxidation rate by differentiating you + + align:start position:0% +oxidation rate by differentiating you + + + align:start position:0% +oxidation rate by differentiating you +can see it's given by B divided by the + + align:start position:0% +can see it's given by B divided by the + + + align:start position:0% +can see it's given by B divided by the +um this quantity 2x knot plus a so this + + align:start position:0% +um this quantity 2x knot plus a so this + + + align:start position:0% +um this quantity 2x knot plus a so this +gives you an idea of of the rate how how + + align:start position:0% +gives you an idea of of the rate how how + + + align:start position:0% +gives you an idea of of the rate how how +rapidly is it + + align:start position:0% +rapidly is it + + + align:start position:0% +rapidly is it +growing so these equations are very + + align:start position:0% +growing so these equations are very + + + align:start position:0% +growing so these equations are very +general and what they describe as the + + align:start position:0% +general and what they describe as the + + + align:start position:0% +general and what they describe as the +growth kinetics for oxidation when + + align:start position:0% +growth kinetics for oxidation when + + + align:start position:0% +growth kinetics for oxidation when +you're in these falling conditions we + + align:start position:0% +you're in these falling conditions we + + + align:start position:0% +you're in these falling conditions we +have to remind ourselves they it only + + align:start position:0% +have to remind ourselves they it only + + + align:start position:0% +have to remind ourselves they it only +applies for certain you know basic case + + align:start position:0% +applies for certain you know basic case + + + align:start position:0% +applies for certain you know basic case +so this means when it's pler oxidation + + align:start position:0% +so this means when it's pler oxidation + + + align:start position:0% +so this means when it's pler oxidation +so I'm just oxidizing a flat surface + + align:start position:0% +so I'm just oxidizing a flat surface + + + align:start position:0% +so I'm just oxidizing a flat surface +we'll talk next time when you have a + + align:start position:0% +we'll talk next time when you have a + + + align:start position:0% +we'll talk next time when you have a +surface that has structure on it the + + align:start position:0% +surface that has structure on it the + + + align:start position:0% +surface that has structure on it the +equations need to be modified um it's + + align:start position:0% +equations need to be modified um it's + + + align:start position:0% +equations need to be modified um it's +planer and it's unpatterned so this is + + align:start position:0% +planer and it's unpatterned so this is + + + align:start position:0% +planer and it's unpatterned so this is +just an unpatterned surface this assumes + + align:start position:0% +just an unpatterned surface this assumes + + + align:start position:0% +just an unpatterned surface this assumes +that the Silicon is lightly doped that + + align:start position:0% +that the Silicon is lightly doped that + + + align:start position:0% +that the Silicon is lightly doped that +you can use these numbers heavily doped + + align:start position:0% +you can use these numbers heavily doped + + + align:start position:0% +you can use these numbers heavily doped +oxidation we'll talk about next time uh + + align:start position:0% +oxidation we'll talk about next time uh + + + align:start position:0% +oxidation we'll talk about next time uh +a simple ambient such as oxygen dry O2 + + align:start position:0% +a simple ambient such as oxygen dry O2 + + + align:start position:0% +a simple ambient such as oxygen dry O2 +or water is is assumed if you're going + + align:start position:0% +or water is is assumed if you're going + + + align:start position:0% +or water is is assumed if you're going +to add other gases nitrous oxide and + + align:start position:0% +to add other gases nitrous oxide and + + + align:start position:0% +to add other gases nitrous oxide and +other things that people do to grow High + + align:start position:0% +other things that people do to grow High + + + align:start position:0% +other things that people do to grow High +K these particular equations don't apply + + align:start position:0% +K these particular equations don't apply + + + align:start position:0% +K these particular equations don't apply +exactly um and when this also these + + align:start position:0% +exactly um and when this also these + + + align:start position:0% +exactly um and when this also these +equations work when the final oxide + + align:start position:0% +equations work when the final oxide + + + align:start position:0% +equations work when the final oxide +thickness is larger than about 20 nmet + + align:start position:0% +thickness is larger than about 20 nmet + + + align:start position:0% +thickness is larger than about 20 nmet +about 200 + + align:start position:0% +about 200 + + + align:start position:0% +about 200 +anrs they work quite well but um uh so + + align:start position:0% +anrs they work quite well but um uh so + + + align:start position:0% +anrs they work quite well but um uh so +that's a certain number of limitations + + align:start position:0% +that's a certain number of limitations + + + align:start position:0% +that's a certain number of limitations +still very useful because what we're + + align:start position:0% +still very useful because what we're + + + align:start position:0% +still very useful because what we're +going to do from here is now make + + align:start position:0% +going to do from here is now make + + + align:start position:0% +going to do from here is now make +Corrections right off the bat though + + align:start position:0% +Corrections right off the bat though + + + align:start position:0% +Corrections right off the bat though +when when you see this 20 nanometer + + align:start position:0% +when when you see this 20 nanometer + + + align:start position:0% +when when you see this 20 nanometer +number what do you think of I mean gate + + align:start position:0% +number what do you think of I mean gate + + + align:start position:0% +number what do you think of I mean gate +oxides today just from you're reading of + + align:start position:0% +oxides today just from you're reading of + + + align:start position:0% +oxides today just from you're reading of +the itrs and high performance devices + + align:start position:0% +the itrs and high performance devices + + + align:start position:0% +the itrs and high performance devices +how what are they are they less than or + + align:start position:0% +how what are they are they less than or + + + align:start position:0% +how what are they are they less than or +or greater than 20 + + align:start position:0% +or greater than 20 + + + align:start position:0% +or greater than 20 +nanometers less than significantly less + + align:start position:0% +nanometers less than significantly less + + + align:start position:0% +nanometers less than significantly less +than for most high performance devices + + align:start position:0% +than for most high performance devices + + + align:start position:0% +than for most high performance devices +so this tells us right off the bat if we + + align:start position:0% +so this tells us right off the bat if we + + + align:start position:0% +so this tells us right off the bat if we +want to use deal Grove to model a + + align:start position:0% +want to use deal Grove to model a + + + align:start position:0% +want to use deal Grove to model a +standard sort of gate oxide thickness + + align:start position:0% +standard sort of gate oxide thickness + + + align:start position:0% +standard sort of gate oxide thickness +that someone might be growing 100 + + align:start position:0% +that someone might be growing 100 + + + align:start position:0% +that someone might be growing 100 +angstroms or less um it's not going to + + align:start position:0% +angstroms or less um it's not going to + + + align:start position:0% +angstroms or less um it's not going to +be perfect + + align:start position:0% +be perfect + + + align:start position:0% +be perfect +we're going to have to make corrections + + align:start position:0% +we're going to have to make corrections + + + align:start position:0% +we're going to have to make corrections +to this and we'll talk today about those + + align:start position:0% +to this and we'll talk today about those + + + align:start position:0% +to this and we'll talk today about those +thin oxid thin oxidation + + align:start position:0% +thin oxid thin oxidation + + + align:start position:0% +thin oxid thin oxidation +models but let's go on to um slide 10 + + align:start position:0% +models but let's go on to um slide 10 + + + align:start position:0% +models but let's go on to um slide 10 +and again just to make a different way + + align:start position:0% +and again just to make a different way + + + align:start position:0% +and again just to make a different way +of of looking at these same equations + + align:start position:0% +of of looking at these same equations + + + align:start position:0% +of of looking at these same equations +I've repeated them um again at the top + + align:start position:0% +I've repeated them um again at the top + + + align:start position:0% +I've repeated them um again at the top +so we don't have to memorize them but + + align:start position:0% +so we don't have to memorize them but + + + align:start position:0% +so we don't have to memorize them but +what we can do now is to take two + + align:start position:0% +what we can do now is to take two + + + align:start position:0% +what we can do now is to take two +limiting + + align:start position:0% +limiting + + + align:start position:0% +limiting +cases one limiting case I'm going to say + + align:start position:0% +cases one limiting case I'm going to say + + + align:start position:0% +cases one limiting case I'm going to say +is when the oxide is relatively thin so + + align:start position:0% +is when the oxide is relatively thin so + + + align:start position:0% +is when the oxide is relatively thin so +X knot uh is relatively small then it + + align:start position:0% +X knot uh is relatively small then it + + + align:start position:0% +X knot uh is relatively small then it +turns out this term here the linear term + + align:start position:0% +turns out this term here the linear term + + + align:start position:0% +turns out this term here the linear term +xot ID B over a um uh is going to + + align:start position:0% +xot ID B over a um uh is going to + + + align:start position:0% +xot ID B over a um uh is going to +dominate over this xnot squar this this + + align:start position:0% +dominate over this xnot squar this this + + + align:start position:0% +dominate over this xnot squar this this +is going to become a smaller term so we + + align:start position:0% +is going to become a smaller term so we + + + align:start position:0% +is going to become a smaller term so we +can ignore this first term and we end up + + align:start position:0% +can ignore this first term and we end up + + + align:start position:0% +can ignore this first term and we end up +that x is proportional to B over a time + + align:start position:0% +that x is proportional to B over a time + + + align:start position:0% +that x is proportional to B over a time +time so it's essentially in thin oxides + + align:start position:0% +time so it's essentially in thin oxides + + + align:start position:0% +time so it's essentially in thin oxides +we have the uh equation is linear in + + align:start position:0% +we have the uh equation is linear in + + + align:start position:0% +we have the uh equation is linear in +time so just um we have a constant + + align:start position:0% +time so just um we have a constant + + + align:start position:0% +time so just um we have a constant +oxidation rate and the thickness just + + align:start position:0% +oxidation rate and the thickness just + + + align:start position:0% +oxidation rate and the thickness just +increases linearly according to this uh + + align:start position:0% +increases linearly according to this uh + + + align:start position:0% +increases linearly according to this uh +deog Grove model for thicker oxides and + + align:start position:0% +deog Grove model for thicker oxides and + + + align:start position:0% +deog Grove model for thicker oxides and +we'll Define later what we mean by + + align:start position:0% +we'll Define later what we mean by + + + align:start position:0% +we'll Define later what we mean by +thicker but at some point this term this + + align:start position:0% +thicker but at some point this term this + + + align:start position:0% +thicker but at some point this term this +x^ squar over B starts to dominate over + + align:start position:0% +x^ squar over B starts to dominate over + + + align:start position:0% +x^ squar over B starts to dominate over +the linear term we can ignore this + + align:start position:0% +the linear term we can ignore this + + + align:start position:0% +the linear term we can ignore this +linear term for long times or very thick + + align:start position:0% +linear term for long times or very thick + + + align:start position:0% +linear term for long times or very thick +oxides it goes like x^ squ is a constant + + align:start position:0% +oxides it goes like x^ squ is a constant + + + align:start position:0% +oxides it goes like x^ squ is a constant +times T so um it's uh basically a + + align:start position:0% +times T so um it's uh basically a + + + align:start position:0% +times T so um it's uh basically a +parabolic uh term so the oxide thickness + + align:start position:0% +parabolic uh term so the oxide thickness + + + align:start position:0% +parabolic uh term so the oxide thickness +starts uh increasing like the square + + align:start position:0% +starts uh increasing like the square + + + align:start position:0% +starts uh increasing like the square +root of time so initially it's going up + + align:start position:0% +root of time so initially it's going up + + + align:start position:0% +root of time so initially it's going up +linearly and then when it becomes thick + + align:start position:0% +linearly and then when it becomes thick + + + align:start position:0% +linearly and then when it becomes thick +enough starts increasing more like a + + align:start position:0% +enough starts increasing more like a + + + align:start position:0% +enough starts increasing more like a +square root kind of function um and that + + align:start position:0% +square root kind of function um and that + + + align:start position:0% +square root kind of function um and that +point you know it's thick enough that + + align:start position:0% +point you know it's thick enough that + + + align:start position:0% +point you know it's thick enough that +diffusion through the oxide is really + + align:start position:0% +diffusion through the oxide is really + + + align:start position:0% +diffusion through the oxide is really +starting to limit you um mathematically + + align:start position:0% +starting to limit you um mathematically + + + align:start position:0% +starting to limit you um mathematically +if you want to see this if you prefer to + + align:start position:0% +if you want to see this if you prefer to + + + align:start position:0% +if you want to see this if you prefer to +think mathematically you're going to + + align:start position:0% +think mathematically you're going to + + + align:start position:0% +think mathematically you're going to +make yourself a plot this is a actually + + align:start position:0% +make yourself a plot this is a actually + + + align:start position:0% +make yourself a plot this is a actually +a log scale a log log plot log on the Y + + align:start position:0% +a log scale a log log plot log on the Y + + + align:start position:0% +a log scale a log log plot log on the Y +log on the X and it's kind of normalized + + align:start position:0% +log on the X and it's kind of normalized + + + align:start position:0% +log on the X and it's kind of normalized +what it's a plot of is X notot ided a + + align:start position:0% +what it's a plot of is X notot ided a + + + align:start position:0% +what it's a plot of is X notot ided a +over2 so we' sort of normalized uh the + + align:start position:0% +over2 so we' sort of normalized uh the + + + align:start position:0% +over2 so we' sort of normalized uh the +um uh the the Y AIS and t plus to ided + + align:start position:0% +um uh the the Y AIS and t plus to ided + + + align:start position:0% +um uh the the Y AIS and t plus to ided +by this constant a^2 over 4B to make it + + align:start position:0% +by this constant a^2 over 4B to make it + + + align:start position:0% +by this constant a^2 over 4B to make it +in in unitless and what you see this + + align:start position:0% +in in unitless and what you see this + + + align:start position:0% +in in unitless and what you see this +solid line + + align:start position:0% +solid line + + + align:start position:0% +solid line +here is uh equal to a plot of xot 2 plus + + align:start position:0% +here is uh equal to a plot of xot 2 plus + + + align:start position:0% +here is uh equal to a plot of xot 2 plus +a x KN = B * T * t plus T so that's the + + align:start position:0% +a x KN = B * T * t plus T so that's the + + + align:start position:0% +a x KN = B * T * t plus T so that's the +exact deal grow model at short time you + + align:start position:0% +exact deal grow model at short time you + + + align:start position:0% +exact deal grow model at short time you +can see it it approaches uh or low + + align:start position:0% +can see it it approaches uh or low + + + align:start position:0% +can see it it approaches uh or low +thicknesses it approaches this linear uh + + align:start position:0% +thicknesses it approaches this linear uh + + + align:start position:0% +thicknesses it approaches this linear uh +rate constant this linear uh equation + + align:start position:0% +rate constant this linear uh equation + + + align:start position:0% +rate constant this linear uh equation +remember on on a semi log plot this has + + align:start position:0% +remember on on a semi log plot this has + + + align:start position:0% +remember on on a semi log plot this has +a certain slope uh and then it has for + + align:start position:0% +a certain slope uh and then it has for + + + align:start position:0% +a certain slope uh and then it has for +longer timeses much longer higher + + align:start position:0% +longer timeses much longer higher + + + align:start position:0% +longer timeses much longer higher +thicknesses it approaches a straight + + align:start position:0% +thicknesses it approaches a straight + + + align:start position:0% +thicknesses it approaches a straight +line This dash line that has half the + + align:start position:0% +line This dash line that has half the + + + align:start position:0% +line This dash line that has half the +slope again linear here versus square + + align:start position:0% +slope again linear here versus square + + + align:start position:0% +slope again linear here versus square +root has half the + + align:start position:0% +root has half the + + + align:start position:0% +root has half the +slope different way of looking at it I + + align:start position:0% +slope different way of looking at it I + + + align:start position:0% +slope different way of looking at it I +actually like you to think a little more + + align:start position:0% +actually like you to think a little more + + + align:start position:0% +actually like you to think a little more +physically not just look at the + + align:start position:0% +physically not just look at the + + + align:start position:0% +physically not just look at the +equations and say which term is big and + + align:start position:0% +equations and say which term is big and + + + align:start position:0% +equations and say which term is big and +which is small in fact it's much easier + + align:start position:0% +which is small in fact it's much easier + + + align:start position:0% +which is small in fact it's much easier +to remember to limiting cases in a + + align:start position:0% +to remember to limiting cases in a + + + align:start position:0% +to remember to limiting cases in a +physical sense uh and that's what's + + align:start position:0% +physical sense uh and that's what's + + + align:start position:0% +physical sense uh and that's what's +being uh shown on slide 11 so if you + + align:start position:0% +being uh shown on slide 11 so if you + + + align:start position:0% +being uh shown on slide 11 so if you +look at the case of a thin oxide it's + + align:start position:0% +look at the case of a thin oxide it's + + + align:start position:0% +look at the case of a thin oxide it's +it's relatively thin what's happening is + + align:start position:0% +it's relatively thin what's happening is + + + align:start position:0% +it's relatively thin what's happening is +is physically is diffusion this is so + + align:start position:0% +is physically is diffusion this is so + + + align:start position:0% +is physically is diffusion this is so +thin the diffusion process happens very + + align:start position:0% +thin the diffusion process happens very + + + align:start position:0% +thin the diffusion process happens very +rapidly compared to the rate at which + + align:start position:0% +rapidly compared to the rate at which + + + align:start position:0% +rapidly compared to the rate at which +those Mo those atoms can react at the + + align:start position:0% +those Mo those atoms can react at the + + + align:start position:0% +those Mo those atoms can react at the +surface so when it's thin the surface + + align:start position:0% +surface so when it's thin the surface + + + align:start position:0% +surface so when it's thin the surface +reaction is what limits it's the slowest + + align:start position:0% +reaction is what limits it's the slowest + + + align:start position:0% +reaction is what limits it's the slowest +uh step any of these serial processes + + align:start position:0% +uh step any of these serial processes + + + align:start position:0% +uh step any of these serial processes +always end up being limited by the rate + + align:start position:0% +always end up being limited by the rate + + + align:start position:0% +always end up being limited by the rate +limiting step is the slowest step so + + align:start position:0% +limiting step is the slowest step so + + + align:start position:0% +limiting step is the slowest step so +clearly when you're thin getting through + + align:start position:0% +clearly when you're thin getting through + + + align:start position:0% +clearly when you're thin getting through +the oxide takes no time at all uh what's + + align:start position:0% +the oxide takes no time at all uh what's + + + align:start position:0% +the oxide takes no time at all uh what's +limiting you is the rate at which you + + align:start position:0% +limiting you is the rate at which you + + + align:start position:0% +limiting you is the rate at which you +can react um and we know that is um a + + align:start position:0% +can react um and we know that is um a + + + align:start position:0% +can react um and we know that is um a +linear process just depends on K + + align:start position:0% +linear process just depends on K + + + align:start position:0% +linear process just depends on K +Subs okay now let's say when you're + + align:start position:0% +Subs okay now let's say when you're + + + align:start position:0% +Subs okay now let's say when you're +thick if you have a thick oxide well + + align:start position:0% +thick if you have a thick oxide well + + + align:start position:0% +thick if you have a thick oxide well +then it the diffusion process is what's + + align:start position:0% +then it the diffusion process is what's + + + align:start position:0% +then it the diffusion process is what's +rate limiting you uh the reaction uh at + + align:start position:0% +rate limiting you uh the reaction uh at + + + align:start position:0% +rate limiting you uh the reaction uh at +the surface can be relatively fast + + align:start position:0% +the surface can be relatively fast + + + align:start position:0% +the surface can be relatively fast +compared to the diffusion rate um so + + align:start position:0% +compared to the diffusion rate um so + + + align:start position:0% +compared to the diffusion rate um so +diffuses rate limit and that process uh + + align:start position:0% +diffuses rate limit and that process uh + + + align:start position:0% +diffuses rate limit and that process uh +ends up depending uh on on a square has + + align:start position:0% +ends up depending uh on on a square has + + + align:start position:0% +ends up depending uh on on a square has +a square root type uh dependence on time + + align:start position:0% +a square root type uh dependence on time + + + align:start position:0% +a square root type uh dependence on time +um so uh in in uh in both cases though + + align:start position:0% +um so uh in in uh in both cases though + + + align:start position:0% +um so uh in in uh in both cases though +and just for these these little diagrams + + align:start position:0% +and just for these these little diagrams + + + align:start position:0% +and just for these these little diagrams +I drew C star Remember is the solubility + + align:start position:0% +I drew C star Remember is the solubility + + + align:start position:0% +I drew C star Remember is the solubility +of the oxidant and the oxide so in the + + align:start position:0% +of the oxidant and the oxide so in the + + + align:start position:0% +of the oxidant and the oxide so in the +thin case you diffuse very rapidly + + align:start position:0% +thin case you diffuse very rapidly + + + align:start position:0% +thin case you diffuse very rapidly +through you have almost uh no gradient + + align:start position:0% +through you have almost uh no gradient + + + align:start position:0% +through you have almost uh no gradient +uh in in in the oxide you're getting + + align:start position:0% +uh in in in the oxide you're getting + + + align:start position:0% +uh in in in the oxide you're getting +through very rapidly just by virtue of + + align:start position:0% +through very rapidly just by virtue of + + + align:start position:0% +through very rapidly just by virtue of +it so thin in a thick Case C star is a + + align:start position:0% +it so thin in a thick Case C star is a + + + align:start position:0% +it so thin in a thick Case C star is a +solubility that's what you have at the + + align:start position:0% +solubility that's what you have at the + + + align:start position:0% +solubility that's what you have at the +surface um at the interface it's almost + + align:start position:0% +surface um at the interface it's almost + + + align:start position:0% +surface um at the interface it's almost +going to zero because again you're rate + + align:start position:0% +going to zero because again you're rate + + + align:start position:0% +going to zero because again you're rate +limited by the rate of of diffusion you + + align:start position:0% +limited by the rate of of diffusion you + + + align:start position:0% +limited by the rate of of diffusion you +have a large gradient so this this uh + + align:start position:0% +have a large gradient so this this uh + + + align:start position:0% +have a large gradient so this this uh +flux through the oxide is being driven + + align:start position:0% +flux through the oxide is being driven + + + align:start position:0% +flux through the oxide is being driven +by this this + + align:start position:0% +by this this + + + align:start position:0% +by this this +gradient so those are the two limiting + + align:start position:0% +gradient so those are the two limiting + + + align:start position:0% +gradient so those are the two limiting +cases one depends on diffusion the other + + align:start position:0% +cases one depends on diffusion the other + + + align:start position:0% +cases one depends on diffusion the other +is limited by surface + + align:start position:0% + + + + align:start position:0% + +reaction uh slide 12 was just a little + + align:start position:0% +reaction uh slide 12 was just a little + + + align:start position:0% +reaction uh slide 12 was just a little +example of if if you're an + + align:start position:0% +example of if if you're an + + + align:start position:0% +example of if if you're an +experimentalist how do you sit down and + + align:start position:0% +experimentalist how do you sit down and + + + align:start position:0% +experimentalist how do you sit down and +how do people in the old days used to do + + align:start position:0% +how do people in the old days used to do + + + align:start position:0% +how do people in the old days used to do +this well it's pretty simple + + align:start position:0% +this well it's pretty simple + + + align:start position:0% +this well it's pretty simple +experimentally you just do uh oxidize a + + align:start position:0% +experimentally you just do uh oxidize a + + + align:start position:0% +experimentally you just do uh oxidize a +bunch of uh Wafers the same temperature + + align:start position:0% +bunch of uh Wafers the same temperature + + + align:start position:0% +bunch of uh Wafers the same temperature +for different times and you plot the + + align:start position:0% +for different times and you plot the + + + align:start position:0% +for different times and you plot the +oxide thickness is measured versus time + + align:start position:0% +oxide thickness is measured versus time + + + align:start position:0% +oxide thickness is measured versus time +you'll see this linear dependence at + + align:start position:0% +you'll see this linear dependence at + + + align:start position:0% +you'll see this linear dependence at +first and then it'll start to bend over + + align:start position:0% +first and then it'll start to bend over + + + align:start position:0% +first and then it'll start to bend over +where it's square root easy way to do it + + align:start position:0% +where it's square root easy way to do it + + + align:start position:0% +where it's square root easy way to do it +is to plot X um instead X notot instead + + align:start position:0% +is to plot X um instead X notot instead + + + align:start position:0% +is to plot X um instead X notot instead +of as a function of time but T time + + align:start position:0% +of as a function of time but T time + + + align:start position:0% +of as a function of time but T time +divided by X knot and you'll find out + + align:start position:0% +divided by X knot and you'll find out + + + align:start position:0% +divided by X knot and you'll find out +that the slope if you if you just + + align:start position:0% +that the slope if you if you just + + + align:start position:0% +that the slope if you if you just +manipulate those simple linear equations + + align:start position:0% +manipulate those simple linear equations + + + align:start position:0% +manipulate those simple linear equations +the slope is the parameter B and the Y + + align:start position:0% +the slope is the parameter B and the Y + + + align:start position:0% +the slope is the parameter B and the Y +intercept is the parameter minus a so + + align:start position:0% +intercept is the parameter minus a so + + + align:start position:0% +intercept is the parameter minus a so +for the D gr model it's very simple + + align:start position:0% +for the D gr model it's very simple + + + align:start position:0% +for the D gr model it's very simple +experimentally if you do this kind of + + align:start position:0% +experimentally if you do this kind of + + + align:start position:0% +experimentally if you do this kind of +plot uh to extract those two + + align:start position:0% +plot uh to extract those two + + + align:start position:0% +plot uh to extract those two +parameters + + align:start position:0% + + + + align:start position:0% + +these are some actual um calculations of + + align:start position:0% +these are some actual um calculations of + + + align:start position:0% +these are some actual um calculations of +the oxidation rates in dry on on slide + + align:start position:0% +the oxidation rates in dry on on slide + + + align:start position:0% +the oxidation rates in dry on on slide +13 in dry oxygen using the deal Grove + + align:start position:0% +13 in dry oxygen using the deal Grove + + + align:start position:0% +13 in dry oxygen using the deal Grove +model um this is for 10 silicon now so + + align:start position:0% +model um this is for 10 silicon now so + + + align:start position:0% +model um this is for 10 silicon now so +10 silicon is much more likely what + + align:start position:0% +10 silicon is much more likely what + + + align:start position:0% +10 silicon is much more likely what +you're going to be using in a silicon uh + + align:start position:0% +you're going to be using in a silicon uh + + + align:start position:0% +you're going to be using in a silicon uh +silicon manufacturing process or + + align:start position:0% +silicon manufacturing process or + + + align:start position:0% +silicon manufacturing process or +probably in your research so it's a plot + + align:start position:0% +probably in your research so it's a plot + + + align:start position:0% +probably in your research so it's a plot +on the left axis linear scale of oxide + + align:start position:0% +on the left axis linear scale of oxide + + + align:start position:0% +on the left axis linear scale of oxide +thickness as a function of time uh and + + align:start position:0% +thickness as a function of time uh and + + + align:start position:0% +thickness as a function of time uh and +what you do see is um a linear regime + + align:start position:0% +what you do see is um a linear regime + + + align:start position:0% +what you do see is um a linear regime +here say uh for thin when you're at thin + + align:start position:0% +here say uh for thin when you're at thin + + + align:start position:0% +here say uh for thin when you're at thin +oxides say below um below 0.1 microns or + + align:start position:0% +oxides say below um below 0.1 microns or + + + align:start position:0% +oxides say below um below 0.1 microns or +maybe half of that 500 angstroms the + + align:start position:0% +maybe half of that 500 angstroms the + + + align:start position:0% +maybe half of that 500 angstroms the +lines look quite linear uh and then you + + align:start position:0% +lines look quite linear uh and then you + + + align:start position:0% +lines look quite linear uh and then you +start they start bending over so they're + + align:start position:0% +start they start bending over so they're + + + align:start position:0% +start they start bending over so they're +followed by this sort of parabolic + + align:start position:0% +followed by this sort of parabolic + + + align:start position:0% +followed by this sort of parabolic +behavior uh where they they grow less + + align:start position:0% +behavior uh where they they grow less + + + align:start position:0% +behavior uh where they they grow less +rapidly and you can also see look at the + + align:start position:0% +rapidly and you can also see look at the + + + align:start position:0% +rapidly and you can also see look at the +thicknesses uh as we mentioned before + + align:start position:0% +thicknesses uh as we mentioned before + + + align:start position:0% +thicknesses uh as we mentioned before +dry oxides even at high temperatures of + + align:start position:0% +dry oxides even at high temperatures of + + + align:start position:0% +dry oxides even at high temperatures of +1100 which is quite high for a furnace + + align:start position:0% +1100 which is quite high for a furnace + + + align:start position:0% +1100 which is quite high for a furnace +um you're really limited for practical + + align:start position:0% +um you're really limited for practical + + + align:start position:0% +um you're really limited for practical +times you don't want to be leaving the + + align:start position:0% +times you don't want to be leaving the + + + align:start position:0% +times you don't want to be leaving the +wafers in there any more than a few + + align:start position:0% +wafers in there any more than a few + + + align:start position:0% +wafers in there any more than a few +hours 4 hours 6 hours whatever you're + + align:start position:0% +hours 4 hours 6 hours whatever you're + + + align:start position:0% +hours 4 hours 6 hours whatever you're +limited to things on the order of uh a + + align:start position:0% +limited to things on the order of uh a + + + align:start position:0% +limited to things on the order of uh a +thousand 2,000 angstroms would from a + + align:start position:0% +thousand 2,000 angstroms would from a + + + align:start position:0% +thousand 2,000 angstroms would from a +practical point of view where people + + align:start position:0% +practical point of view where people + + + align:start position:0% +practical point of view where people +grow dry oxides um of course you could + + align:start position:0% +grow dry oxides um of course you could + + + align:start position:0% +grow dry oxides um of course you could +leave it in the furnace for days but + + align:start position:0% +leave it in the furnace for days but + + + align:start position:0% +leave it in the furnace for days but +that is not very economical in terms of + + align:start position:0% +that is not very economical in terms of + + + align:start position:0% +that is not very economical in terms of +use of the furnace use of electricity + + align:start position:0% +use of the furnace use of electricity + + + align:start position:0% +use of the furnace use of electricity +and all the resources so if you want to + + align:start position:0% +and all the resources so if you want to + + + align:start position:0% +and all the resources so if you want to +to grow an oxide in this thickness range + + align:start position:0% +to grow an oxide in this thickness range + + + align:start position:0% +to grow an oxide in this thickness range +you use a dry oxide if you want to go + + align:start position:0% +you use a dry oxide if you want to go + + + align:start position:0% +you use a dry oxide if you want to go +well above that you should be going to + + align:start position:0% +well above that you should be going to + + + align:start position:0% +well above that you should be going to +wet oxidation because the oxidation rate + + align:start position:0% +wet oxidation because the oxidation rate + + + align:start position:0% +wet oxidation because the oxidation rate +constant are so much + + align:start position:0% +constant are so much + + + align:start position:0% +constant are so much +higher in fact on the next slide slide + + align:start position:0% +higher in fact on the next slide slide + + + align:start position:0% +higher in fact on the next slide slide +14 you can see the oxidation rate const + + align:start position:0% +14 you can see the oxidation rate const + + + align:start position:0% +14 you can see the oxidation rate const +of the oxidation uh for oxide thickness + + align:start position:0% +of the oxidation uh for oxide thickness + + + align:start position:0% +of the oxidation uh for oxide thickness +versus time for wet uh ambient for + + align:start position:0% +versus time for wet uh ambient for + + + align:start position:0% +versus time for wet uh ambient for +moisture ambient using deal Grove and + + align:start position:0% +moisture ambient using deal Grove and + + + align:start position:0% +moisture ambient using deal Grove and +now look at the time of say two or three + + align:start position:0% +now look at the time of say two or three + + + align:start position:0% +now look at the time of say two or three +hours um instead of growing a thousand + + align:start position:0% +hours um instead of growing a thousand + + + align:start position:0% +hours um instead of growing a thousand +angstroms um or so at 1100 degrees + + align:start position:0% +angstroms um or so at 1100 degrees + + + align:start position:0% +angstroms um or so at 1100 degrees +you're growing + + align:start position:0% +you're growing + + + align:start position:0% +you're growing +Micron um here after about 2 hours at + + align:start position:0% +Micron um here after about 2 hours at + + + align:start position:0% +Micron um here after about 2 hours at +1100° in wet uh wet ambient about a + + align:start position:0% +1100° in wet uh wet ambient about a + + + align:start position:0% +1100° in wet uh wet ambient about a +micron so uh much faster than dry + + align:start position:0% +micron so uh much faster than dry + + + align:start position:0% +micron so uh much faster than dry +oxidation or is a magnitude + + align:start position:0% +oxidation or is a magnitude + + + align:start position:0% +oxidation or is a magnitude +faster uh and the reason as it turns out + + align:start position:0% +faster uh and the reason as it turns out + + + align:start position:0% +faster uh and the reason as it turns out +the physical reason why is that the + + align:start position:0% +the physical reason why is that the + + + align:start position:0% +the physical reason why is that the +solubility C star uh of water vapor is + + align:start position:0% +solubility C star uh of water vapor is + + + align:start position:0% +solubility C star uh of water vapor is +much higher uh than the solubility of + + align:start position:0% +much higher uh than the solubility of + + + align:start position:0% +much higher uh than the solubility of +oxygen of the oxygen molecule uh for + + align:start position:0% +oxygen of the oxygen molecule uh for + + + align:start position:0% +oxygen of the oxygen molecule uh for +various reasons just because of the + + align:start position:0% +various reasons just because of the + + + align:start position:0% +various reasons just because of the +configuration of the molecule and the + + align:start position:0% +configuration of the molecule and the + + + align:start position:0% +configuration of the molecule and the +size of the interstitial spaces water + + align:start position:0% +size of the interstitial spaces water + + + align:start position:0% +size of the interstitial spaces water +vapor is just easier to get in there um + + align:start position:0% +vapor is just easier to get in there um + + + align:start position:0% +vapor is just easier to get in there um +so it has a much higher solubility so + + align:start position:0% +so it has a much higher solubility so + + + align:start position:0% +so it has a much higher solubility so +that whole um concentration can be + + align:start position:0% +that whole um concentration can be + + + align:start position:0% +that whole um concentration can be +elevated and you can oxidize it at a + + align:start position:0% +elevated and you can oxidize it at a + + + align:start position:0% +elevated and you can oxidize it at a +much faster rate so you need a thick + + align:start position:0% +much faster rate so you need a thick + + + align:start position:0% +much faster rate so you need a thick +oxide you use Mo uh + + align:start position:0% + + + + align:start position:0% + +moisture Yeah question real all of the + + align:start position:0% +moisture Yeah question real all of the + + + align:start position:0% +moisture Yeah question real all of the +all of the side um + + align:start position:0% +all of the side um + + + align:start position:0% +all of the side um +doesn't it uh okay so the question is is + + align:start position:0% +doesn't it uh okay so the question is is + + + align:start position:0% +doesn't it uh okay so the question is is +is going back to let's say um slide uh + + align:start position:0% +is going back to let's say um slide uh + + + align:start position:0% +is going back to let's say um slide uh +11 uh maybe of these limiting cases what + + align:start position:0% +11 uh maybe of these limiting cases what + + + align:start position:0% +11 uh maybe of these limiting cases what +happens in in a real case uh if you have + + align:start position:0% +happens in in a real case uh if you have + + + align:start position:0% +happens in in a real case uh if you have +an oxident diffusing through the oxide + + align:start position:0% +an oxident diffusing through the oxide + + + align:start position:0% +an oxident diffusing through the oxide +and uh does it all react is there any + + align:start position:0% +and uh does it all react is there any + + + align:start position:0% +and uh does it all react is there any +unreacted uh species at the interface uh + + align:start position:0% +unreacted uh species at the interface uh + + + align:start position:0% +unreacted uh species at the interface uh +basically it does have to react now uh + + align:start position:0% +basically it does have to react now uh + + + align:start position:0% +basically it does have to react now uh +um and then if if the reaction rate is + + align:start position:0% +um and then if if the reaction rate is + + + align:start position:0% +um and then if if the reaction rate is +what's limiting you um then uh then + + align:start position:0% +what's limiting you um then uh then + + + align:start position:0% +what's limiting you um then uh then +you're you're sort of in this regime but + + align:start position:0% +you're you're sort of in this regime but + + + align:start position:0% +you're you're sort of in this regime but +there can there will be a certain amount + + align:start position:0% +there can there will be a certain amount + + + align:start position:0% +there can there will be a certain amount +of oxidant that doesn't react um and + + align:start position:0% +of oxidant that doesn't react um and + + + align:start position:0% +of oxidant that doesn't react um and +that can lead to uh perhaps excess uh + + align:start position:0% +that can lead to uh perhaps excess uh + + + align:start position:0% +that can lead to uh perhaps excess uh +charges and things like that some of the + + align:start position:0% +charges and things like that some of the + + + align:start position:0% +charges and things like that some of the +more realistic as aspects of the ox + + align:start position:0% +more realistic as aspects of the ox + + + align:start position:0% +more realistic as aspects of the ox +oxidation process that you're left over + + align:start position:0% +oxidation process that you're left over + + + align:start position:0% +oxidation process that you're left over +so it can affect the um uh the quality + + align:start position:0% +so it can affect the um uh the quality + + + align:start position:0% +so it can affect the um uh the quality +oxide to a certain extent and what you + + align:start position:0% +oxide to a certain extent and what you + + + align:start position:0% +oxide to a certain extent and what you +generally find is that wet oxides uh you + + align:start position:0% +generally find is that wet oxides uh you + + + align:start position:0% +generally find is that wet oxides uh you +don't see a whole lot of people growing + + align:start position:0% +don't see a whole lot of people growing + + + align:start position:0% +don't see a whole lot of people growing +gate oxides by wet well because they + + align:start position:0% +gate oxides by wet well because they + + + align:start position:0% +gate oxides by wet well because they +want thinner but even in the old days + + align:start position:0% +want thinner but even in the old days + + + align:start position:0% +want thinner but even in the old days +when a gate oxide was thicker uh 500 + + align:start position:0% +when a gate oxide was thicker uh 500 + + + align:start position:0% +when a gate oxide was thicker uh 500 +anrs or whatever he didn't see people + + align:start position:0% +anrs or whatever he didn't see people + + + align:start position:0% +anrs or whatever he didn't see people +growing them in a wet ambient uh and the + + align:start position:0% +growing them in a wet ambient uh and the + + + align:start position:0% +growing them in a wet ambient uh and the +oxidation ratees a lot faster the + + align:start position:0% +oxidation ratees a lot faster the + + + align:start position:0% +oxidation ratees a lot faster the +quality of the oxide the the number of + + align:start position:0% +quality of the oxide the the number of + + + align:start position:0% +quality of the oxide the the number of +interface States and things like that + + align:start position:0% +interface States and things like that + + + align:start position:0% +interface States and things like that +tends to to be higher for a wet oxide um + + align:start position:0% +tends to to be higher for a wet oxide um + + + align:start position:0% +tends to to be higher for a wet oxide um +so uh typically um what you do if you're + + align:start position:0% +so uh typically um what you do if you're + + + align:start position:0% +so uh typically um what you do if you're +trying to grow a gate oxide is you grow + + align:start position:0% +trying to grow a gate oxide is you grow + + + align:start position:0% +trying to grow a gate oxide is you grow +it dry or if you want to make it um + + align:start position:0% +it dry or if you want to make it um + + + align:start position:0% +it dry or if you want to make it um +thick and you have practical limitations + + align:start position:0% +thick and you have practical limitations + + + align:start position:0% +thick and you have practical limitations +you go a dry step a wet step and then a + + align:start position:0% +you go a dry step a wet step and then a + + + align:start position:0% +you go a dry step a wet step and then a +dry Step at the end so the interface was + + align:start position:0% +dry Step at the end so the interface was + + + align:start position:0% +dry Step at the end so the interface was +always grown in a dry step to try to + + align:start position:0% +always grown in a dry step to try to + + + align:start position:0% +always grown in a dry step to try to +reduce the interface uh State density um + + align:start position:0% +reduce the interface uh State density um + + + align:start position:0% +reduce the interface uh State density um +so if you need an oxide gate oxide + + align:start position:0% +so if you need an oxide gate oxide + + + align:start position:0% +so if you need an oxide gate oxide +that's a th a you do what they call a + + align:start position:0% +that's a th a you do what they call a + + + align:start position:0% +that's a th a you do what they call a +dry wet dry um so it does matter the + + align:start position:0% +dry wet dry um so it does matter the + + + align:start position:0% +dry wet dry um so it does matter the +oxidation rate being too high is not the + + align:start position:0% +oxidation rate being too high is not the + + + align:start position:0% +oxidation rate being too high is not the +greatest thing in the world for in terms + + align:start position:0% +greatest thing in the world for in terms + + + align:start position:0% +greatest thing in the world for in terms +of the device properties I think there + + align:start position:0% +of the device properties I think there + + + align:start position:0% +of the device properties I think there +was there a hand in the back or did I + + align:start position:0% +was there a hand in the back or did I + + + align:start position:0% +was there a hand in the back or did I +missed question + + align:start position:0% +missed question + + + align:start position:0% +missed question +okay okay good so let's go on so those + + align:start position:0% +okay okay good so let's go on so those + + + align:start position:0% +okay okay good so let's go on so those +are the wet oxide kinetics let's go on + + align:start position:0% +are the wet oxide kinetics let's go on + + + align:start position:0% +are the wet oxide kinetics let's go on +to slide number 15 and just show some + + align:start position:0% +to slide number 15 and just show some + + + align:start position:0% +to slide number 15 and just show some +examples uh now right off the bat + + align:start position:0% +examples uh now right off the bat + + + align:start position:0% +examples uh now right off the bat +unfortunately um showing an example + + align:start position:0% +unfortunately um showing an example + + + align:start position:0% +unfortunately um showing an example +that's to which the deal Grove model + + align:start position:0% +that's to which the deal Grove model + + + align:start position:0% +that's to which the deal Grove model +doesn't doesn't perfectly apply but + + align:start position:0% +doesn't doesn't perfectly apply but + + + align:start position:0% +doesn't doesn't perfectly apply but +we'll apply it anyway and we'll next + + align:start position:0% +we'll apply it anyway and we'll next + + + align:start position:0% +we'll apply it anyway and we'll next +time we'll talk about why it's not + + align:start position:0% +time we'll talk about why it's not + + + align:start position:0% +time we'll talk about why it's not +perfect but there is a process called um + + align:start position:0% +perfect but there is a process called um + + + align:start position:0% +perfect but there is a process called um +uh just to make this a little more + + align:start position:0% +uh just to make this a little more + + + align:start position:0% +uh just to make this a little more +interesting called recess + + align:start position:0% +interesting called recess + + + align:start position:0% +interesting called recess +loose uh local oxidation which can be + + align:start position:0% +loose uh local oxidation which can be + + + align:start position:0% +loose uh local oxidation which can be +used to provide this lateral isolation + + align:start position:0% +used to provide this lateral isolation + + + align:start position:0% +used to provide this lateral isolation +between device a and device B um we need + + align:start position:0% +between device a and device B um we need + + + align:start position:0% +between device a and device B um we need +to grow an oxide uh here and uh it + + align:start position:0% +to grow an oxide uh here and uh it + + + align:start position:0% +to grow an oxide uh here and uh it +results in a more planer surface than + + align:start position:0% +results in a more planer surface than + + + align:start position:0% +results in a more planer surface than +standard Locos remember standard Locos + + align:start position:0% +standard Locos remember standard Locos + + + align:start position:0% +standard Locos remember standard Locos +look like this um we have a very not + + align:start position:0% +look like this um we have a very not + + + align:start position:0% +look like this um we have a very not +when we're done and you strip off this + + align:start position:0% +when we're done and you strip off this + + + align:start position:0% +when we're done and you strip off this +nitrite up in the upper right you have a + + align:start position:0% +nitrite up in the upper right you have a + + + align:start position:0% +nitrite up in the upper right you have a +very nonplanar surface uh introduced um + + align:start position:0% +very nonplanar surface uh introduced um + + + align:start position:0% +very nonplanar surface uh introduced um +you've got this this region up here + + align:start position:0% +you've got this this region up here + + + align:start position:0% +you've got this this region up here +where the oxide pushed up uh and so the + + align:start position:0% +where the oxide pushed up uh and so the + + + align:start position:0% +where the oxide pushed up uh and so the +surface is not very planer recess losis + + align:start position:0% +surface is not very planer recess losis + + + align:start position:0% +surface is not very planer recess losis +the basis basic idea is you etch a + + align:start position:0% +the basis basic idea is you etch a + + + align:start position:0% +the basis basic idea is you etch a +trench first so here I've etched in the + + align:start position:0% +trench first so here I've etched in the + + + align:start position:0% +trench first so here I've etched in the +Silicon um around the Silicon nitrate + + align:start position:0% +Silicon um around the Silicon nitrate + + + align:start position:0% +Silicon um around the Silicon nitrate +I've etched a half Micron deep + + align:start position:0% +I've etched a half Micron deep + + + align:start position:0% +I've etched a half Micron deep +trench uh and now we assume I'm going to + + align:start position:0% +trench uh and now we assume I'm going to + + + align:start position:0% +trench uh and now we assume I'm going to +subject that wafer to Thermal oxidation + + align:start position:0% +subject that wafer to Thermal oxidation + + + align:start position:0% +subject that wafer to Thermal oxidation +well on the left and the right side of + + align:start position:0% +well on the left and the right side of + + + align:start position:0% +well on the left and the right side of +the trench um uh that should say silicon + + align:start position:0% +the trench um uh that should say silicon + + + align:start position:0% +the trench um uh that should say silicon +uh silicon nitride sorry this this left + + align:start position:0% +uh silicon nitride sorry this this left + + + align:start position:0% +uh silicon nitride sorry this this left +and right side should both be silicon + + align:start position:0% +and right side should both be silicon + + + align:start position:0% +and right side should both be silicon +nitrate there's no oxidation taking + + align:start position:0% +nitrate there's no oxidation taking + + + align:start position:0% +nitrate there's no oxidation taking +place so maybe correct this hand out on + + align:start position:0% +place so maybe correct this hand out on + + + align:start position:0% +place so maybe correct this hand out on +the right where it's pointing to S2 that + + align:start position:0% +the right where it's pointing to S2 that + + + align:start position:0% +the right where it's pointing to S2 that +should say silicon + + align:start position:0% +should say silicon + + + align:start position:0% +should say silicon +nitrite uh si3 and4 so we're only + + align:start position:0% +nitrite uh si3 and4 so we're only + + + align:start position:0% +nitrite uh si3 and4 so we're only +oxidizing we're assuming in this this + + align:start position:0% +oxidizing we're assuming in this this + + + align:start position:0% +oxidizing we're assuming in this this +trench region now this schematic is + + align:start position:0% +trench region now this schematic is + + + align:start position:0% +trench region now this schematic is +highly schematic it's not including any + + align:start position:0% +highly schematic it's not including any + + + align:start position:0% +highly schematic it's not including any +birds beak effects which we'll talk + + align:start position:0% +birds beak effects which we'll talk + + + align:start position:0% +birds beak effects which we'll talk +about where they originate from or any + + align:start position:0% +about where they originate from or any + + + align:start position:0% +about where they originate from or any +two-dimensional oxidation we're going to + + align:start position:0% +two-dimensional oxidation we're going to + + + align:start position:0% +two-dimensional oxidation we're going to +do a very simple calculation of how long + + align:start position:0% +do a very simple calculation of how long + + + align:start position:0% +do a very simple calculation of how long +would it take to fill that to make a + + align:start position:0% +would it take to fill that to make a + + + align:start position:0% +would it take to fill that to make a +planer surf Sur uh assuming I was half + + align:start position:0% +planer surf Sur uh assuming I was half + + + align:start position:0% +planer surf Sur uh assuming I was half +Micron uh down + + align:start position:0% + + + + align:start position:0% + +yeah there is in between yeah it's just + + align:start position:0% +yeah there is in between yeah it's just + + + align:start position:0% +yeah there is in between yeah it's just +the arrow got Mis uh displaced this + + align:start position:0% +the arrow got Mis uh displaced this + + + align:start position:0% +the arrow got Mis uh displaced this +arrow is actually pointing to the top + + align:start position:0% +arrow is actually pointing to the top + + + align:start position:0% +arrow is actually pointing to the top +region which is the Silicon nitride + + align:start position:0% +region which is the Silicon nitride + + + align:start position:0% +region which is the Silicon nitride +there is as was just pointed out uh by + + align:start position:0% +there is as was just pointed out uh by + + + align:start position:0% +there is as was just pointed out uh by +someone in the class here there uh this + + align:start position:0% +someone in the class here there uh this + + + align:start position:0% +someone in the class here there uh this +hatched region is meant to represent the + + align:start position:0% +hatched region is meant to represent the + + + align:start position:0% +hatched region is meant to represent the +sio2 what they call the um padox or the + + align:start position:0% +sio2 what they call the um padox or the + + + align:start position:0% +sio2 what they call the um padox or the +pado oxide they always stress that's + + align:start position:0% +pado oxide they always stress that's + + + align:start position:0% +pado oxide they always stress that's +induced by the nitride so so there is in + + align:start position:0% +induced by the nitride so so there is in + + + align:start position:0% +induced by the nitride so so there is in +fact a thin pad oxide underneath the + + align:start position:0% +fact a thin pad oxide underneath the + + + align:start position:0% +fact a thin pad oxide underneath the +Silicon nitride but what's preventing + + align:start position:0% +Silicon nitride but what's preventing + + + align:start position:0% +Silicon nitride but what's preventing +the oxidation from taking place is this + + align:start position:0% +the oxidation from taking place is this + + + align:start position:0% +the oxidation from taking place is this +silicon nitride Ox si2 itself won't + + align:start position:0% +silicon nitride Ox si2 itself won't + + + align:start position:0% +silicon nitride Ox si2 itself won't +prevent oxidation the oxide will oxidant + + align:start position:0% +prevent oxidation the oxide will oxidant + + + align:start position:0% +prevent oxidation the oxide will oxidant +will diffuse right through it the nice + + align:start position:0% +will diffuse right through it the nice + + + align:start position:0% +will diffuse right through it the nice +thing about silicon nitride is that it's + + align:start position:0% +thing about silicon nitride is that it's + + + align:start position:0% +thing about silicon nitride is that it's +hard to get Ox uh oxygen and moisture to + + align:start position:0% +hard to get Ox uh oxygen and moisture to + + + align:start position:0% +hard to get Ox uh oxygen and moisture to +diffuse through it so it can act as a + + align:start position:0% +diffuse through it so it can act as a + + + align:start position:0% +diffuse through it so it can act as a +mask or as a blocking layer um so you + + align:start position:0% +mask or as a blocking layer um so you + + + align:start position:0% +mask or as a blocking layer um so you +don't oxidize uh underneath it the first + + align:start position:0% +don't oxidize uh underneath it the first + + + align:start position:0% +don't oxidize uh underneath it the first +wor so this oxide that's shown here + + align:start position:0% +wor so this oxide that's shown here + + + align:start position:0% +wor so this oxide that's shown here +underneath it happened before the + + align:start position:0% +underneath it happened before the + + + align:start position:0% +underneath it happened before the +nitrate was put + + align:start position:0% +nitrate was put + + + align:start position:0% +nitrate was put +down okay good + + align:start position:0% +down okay good + + + align:start position:0% +down okay good +point so let's go on to slide 15 and and + + align:start position:0% +point so let's go on to slide 15 and and + + + align:start position:0% +point so let's go on to slide 15 and and +here's just an example uh of a question + + align:start position:0% +here's just an example uh of a question + + + align:start position:0% +here's just an example uh of a question +uh so we're assuming we've edged half + + align:start position:0% +uh so we're assuming we've edged half + + + align:start position:0% +uh so we're assuming we've edged half +Micron down into the wafer below the + + align:start position:0% +Micron down into the wafer below the + + + align:start position:0% +Micron down into the wafer below the +original surface prior to + + align:start position:0% +original surface prior to + + + align:start position:0% +original surface prior to +oxidizing and a simple question might be + + align:start position:0% +oxidizing and a simple question might be + + + align:start position:0% +oxidizing and a simple question might be +how long do I have to put it in the + + align:start position:0% +how long do I have to put it in the + + + align:start position:0% +how long do I have to put it in the +furnace at a th000 degrees assuming uh + + align:start position:0% +furnace at a th000 degrees assuming uh + + + align:start position:0% +furnace at a th000 degrees assuming uh +water water oxidation in H2O to produce + + align:start position:0% +water water oxidation in H2O to produce + + + align:start position:0% +water water oxidation in H2O to produce +a planer surface again we're going to + + align:start position:0% +a planer surface again we're going to + + + align:start position:0% +a planer surface again we're going to +ignore any of the bird's beak effects or + + align:start position:0% +ignore any of the bird's beak effects or + + + align:start position:0% +ignore any of the bird's beak effects or +the stress effects that we know are + + align:start position:0% +the stress effects that we know are + + + align:start position:0% +the stress effects that we know are +there we'll talk about those next time + + align:start position:0% +there we'll talk about those next time + + + align:start position:0% +there we'll talk about those next time +so but Ju Just to make it a little uh + + align:start position:0% +so but Ju Just to make it a little uh + + + align:start position:0% +so but Ju Just to make it a little uh +more interesting we want to fill this up + + align:start position:0% +more interesting we want to fill this up + + + align:start position:0% +more interesting we want to fill this up +to the surface the original surface and + + align:start position:0% +to the surface the original surface and + + + align:start position:0% +to the surface the original surface and +and then make it + + align:start position:0% +and then make it + + + align:start position:0% +and then make it +planer um so we have to be a little + + align:start position:0% +planer um so we have to be a little + + + align:start position:0% +planer um so we have to be a little +careful in doing this because remember + + align:start position:0% +careful in doing this because remember + + + align:start position:0% +careful in doing this because remember +as I'm growing this oxide right here I'm + + align:start position:0% +as I'm growing this oxide right here I'm + + + align:start position:0% +as I'm growing this oxide right here I'm +consuming the Silicon underneath it so + + align:start position:0% +consuming the Silicon underneath it so + + + align:start position:0% +consuming the Silicon underneath it so +you're consuming silicon underneath it + + align:start position:0% +you're consuming silicon underneath it + + + align:start position:0% +you're consuming silicon underneath it +uh but the oxide is also growing up at + + align:start position:0% +uh but the oxide is also growing up at + + + align:start position:0% +uh but the oxide is also growing up at +the same time so it's going it's kind of + + align:start position:0% +the same time so it's going it's kind of + + + align:start position:0% +the same time so it's going it's kind of +starting here very thin and it's kind of + + align:start position:0% +starting here very thin and it's kind of + + + align:start position:0% +starting here very thin and it's kind of +going like this at some point it'll just + + align:start position:0% +going like this at some point it'll just + + + align:start position:0% +going like this at some point it'll just +flat or close to being almost flat uh + + align:start position:0% +flat or close to being almost flat uh + + + align:start position:0% +flat or close to being almost flat uh +with the original + + align:start position:0% +with the original + + + align:start position:0% +with the original +surface so how we figure this out well + + align:start position:0% +surface so how we figure this out well + + + align:start position:0% +surface so how we figure this out well +there there's a um you can make yourself + + align:start position:0% +there there's a um you can make yourself + + + align:start position:0% +there there's a um you can make yourself +a little schematic diagram as shown here + + align:start position:0% +a little schematic diagram as shown here + + + align:start position:0% +a little schematic diagram as shown here +in color in the lower left and in a in a + + align:start position:0% +in color in the lower left and in a in a + + + align:start position:0% +in color in the lower left and in a in a +rough sense for every Micron of silicon + + align:start position:0% +rough sense for every Micron of silicon + + + align:start position:0% +rough sense for every Micron of silicon +I consume so I'm going to as you start + + align:start position:0% +I consume so I'm going to as you start + + + align:start position:0% +I consume so I'm going to as you start +oxidizing I'm going to start bringing + + align:start position:0% +oxidizing I'm going to start bringing + + + align:start position:0% +oxidizing I'm going to start bringing +this trench Point lower every Micron I + + align:start position:0% +this trench Point lower every Micron I + + + align:start position:0% +this trench Point lower every Micron I +go down uh 2 and a half microns or 2.2 + + align:start position:0% +go down uh 2 and a half microns or 2.2 + + + align:start position:0% +go down uh 2 and a half microns or 2.2 +I'm sorry microns of silicon is gr of of + + align:start position:0% +I'm sorry microns of silicon is gr of of + + + align:start position:0% +I'm sorry microns of silicon is gr of of +silicon dioxide + + align:start position:0% +silicon dioxide + + + align:start position:0% +silicon dioxide +S2 um so um you can write this sort of + + align:start position:0% +S2 um so um you can write this sort of + + + align:start position:0% +S2 um so um you can write this sort of +mathematically if I say why is the + + align:start position:0% +mathematically if I say why is the + + + align:start position:0% +mathematically if I say why is the +thickness of the Silicon that was + + align:start position:0% +thickness of the Silicon that was + + + align:start position:0% +thickness of the Silicon that was +consumed then 2.2 * Y is X knot that's + + align:start position:0% +consumed then 2.2 * Y is X knot that's + + + align:start position:0% +consumed then 2.2 * Y is X knot that's +the thickness of the + + align:start position:0% +the thickness of the + + + align:start position:0% +the thickness of the +si2 okay so that's just due to the + + align:start position:0% +si2 okay so that's just due to the + + + align:start position:0% +si2 okay so that's just due to the +volume expansion when you grow oxide so + + align:start position:0% +volume expansion when you grow oxide so + + + align:start position:0% +volume expansion when you grow oxide so +we can we can have that as one uh one + + align:start position:0% +we can we can have that as one uh one + + + align:start position:0% +we can we can have that as one uh one +equation that describes what's going + + align:start position:0% +equation that describes what's going + + + align:start position:0% +equation that describes what's going +on on slide + + align:start position:0% +on on slide + + + align:start position:0% +on on slide +17 um so we we remember that but then we + + align:start position:0% +17 um so we we remember that but then we + + + align:start position:0% +17 um so we we remember that but then we +also know um that the total thickness of + + align:start position:0% +also know um that the total thickness of + + + align:start position:0% +also know um that the total thickness of +oxide grown in order to satisfy this + + align:start position:0% +oxide grown in order to satisfy this + + + align:start position:0% +oxide grown in order to satisfy this +requirement that we fill the trench well + + align:start position:0% +requirement that we fill the trench well + + + align:start position:0% +requirement that we fill the trench well +we want to know a specific ta case where + + align:start position:0% +we want to know a specific ta case where + + + align:start position:0% +we want to know a specific ta case where +X knot is equal to um half Micron which + + align:start position:0% +X knot is equal to um half Micron which + + + align:start position:0% +X knot is equal to um half Micron which +is the original trench depth plus Y + + align:start position:0% +is the original trench depth plus Y + + + align:start position:0% +is the original trench depth plus Y +which is the thickness of silicon + + align:start position:0% +which is the thickness of silicon + + + align:start position:0% +which is the thickness of silicon +consumed so that's just by looking at + + align:start position:0% +consumed so that's just by looking at + + + align:start position:0% +consumed so that's just by looking at +this geometry so the distance from here + + align:start position:0% +this geometry so the distance from here + + + align:start position:0% +this geometry so the distance from here +to here is half Micron that was my + + align:start position:0% +to here is half Micron that was my + + + align:start position:0% +to here is half Micron that was my +original trench plus the Silicon is + + align:start position:0% +original trench plus the Silicon is + + + align:start position:0% +original trench plus the Silicon is +going to get consumed down a little bit + + align:start position:0% +going to get consumed down a little bit + + + align:start position:0% +going to get consumed down a little bit +um and that we're calling the variable y + + align:start position:0% +um and that we're calling the variable y + + + align:start position:0% +um and that we're calling the variable y +we don't know that number yet so we have + + align:start position:0% +we don't know that number yet so we have + + + align:start position:0% +we don't know that number yet so we have +two equations + + align:start position:0% +two equations + + + align:start position:0% +two equations +here uh this x equals 0.5 Micron plus Y + + align:start position:0% +here uh this x equals 0.5 Micron plus Y + + + align:start position:0% +here uh this x equals 0.5 Micron plus Y +and we also have the constraint that 2.2 + + align:start position:0% +and we also have the constraint that 2.2 + + + align:start position:0% +and we also have the constraint that 2.2 +* Y is X knot uh and that's just from + + align:start position:0% +* Y is X knot uh and that's just from + + + align:start position:0% +* Y is X knot uh and that's just from +the volume expansion that we know so if + + align:start position:0% +the volume expansion that we know so if + + + align:start position:0% +the volume expansion that we know so if +we can we can simply now just equate + + align:start position:0% +we can we can simply now just equate + + + align:start position:0% +we can we can simply now just equate +these two equations we have two + + align:start position:0% +these two equations we have two + + + align:start position:0% +these two equations we have two +equations uh and we're going to um uh + + align:start position:0% +equations uh and we're going to um uh + + + align:start position:0% +equations uh and we're going to um uh +set X notot in equation one equal x not + + align:start position:0% +set X notot in equation one equal x not + + + align:start position:0% +set X notot in equation one equal x not +in equation 2 uh and then you can simply + + align:start position:0% +in equation 2 uh and then you can simply + + + align:start position:0% +in equation 2 uh and then you can simply +solve for y so y turns out to be about4 + + align:start position:0% +solve for y so y turns out to be about4 + + + align:start position:0% +solve for y so y turns out to be about4 +Micron so that says we need to consume + + align:start position:0% +Micron so that says we need to consume + + + align:start position:0% +Micron so that says we need to consume +about4 microns in order to just fill the + + align:start position:0% +about4 microns in order to just fill the + + + align:start position:0% +about4 microns in order to just fill the +trench up to the original + + align:start position:0% +trench up to the original + + + align:start position:0% +trench up to the original +surface so I'm going to actually go down + + align:start position:0% +surface so I'm going to actually go down + + + align:start position:0% +surface so I'm going to actually go down +here from the original trench depth I'm + + align:start position:0% +here from the original trench depth I'm + + + align:start position:0% +here from the original trench depth I'm +actually going to consume 04 microns + + align:start position:0% +actually going to consume 04 microns + + + align:start position:0% +actually going to consume 04 microns +down into the wafer so xnot then the + + align:start position:0% +down into the wafer so xnot then the + + + align:start position:0% +down into the wafer so xnot then the +oxide thickness must be two and a half + + align:start position:0% +oxide thickness must be two and a half + + + align:start position:0% +oxide thickness must be two and a half +2.2 times that so it's about 0.9 microns + + align:start position:0% +2.2 times that so it's about 0.9 microns + + + align:start position:0% +2.2 times that so it's about 0.9 microns +so we really have the answer we know we + + align:start position:0% +so we really have the answer we know we + + + align:start position:0% +so we really have the answer we know we +need to grow at 1,000 de up .9 microns + + align:start position:0% +need to grow at 1,000 de up .9 microns + + + align:start position:0% +need to grow at 1,000 de up .9 microns +when we're told we can do it in a wet + + align:start position:0% +when we're told we can do it in a wet + + + align:start position:0% +when we're told we can do it in a wet +ambient so you can calculate being B + + align:start position:0% +ambient so you can calculate being B + + + align:start position:0% +ambient so you can calculate being B +over a using the table uh in table 6.2 + + align:start position:0% +over a using the table uh in table 6.2 + + + align:start position:0% +over a using the table uh in table 6.2 +of your text um so you know this is the + + align:start position:0% +of your text um so you know this is the + + + align:start position:0% +of your text um so you know this is the +deal Grove + + align:start position:0% +deal Grove + + + align:start position:0% +deal Grove +equation um you can just calculate B and + + align:start position:0% +equation um you can just calculate B and + + + align:start position:0% +equation um you can just calculate B and +B over a and solve for the time or if + + align:start position:0% +B over a and solve for the time or if + + + align:start position:0% +B over a and solve for the time or if +you want to go on the next slide I'll + + align:start position:0% +you want to go on the next slide I'll + + + align:start position:0% +you want to go on the next slide I'll +show you use the + + align:start position:0% +show you use the + + + align:start position:0% +show you use the +graph so on slide 18 these are just the + + align:start position:0% +graph so on slide 18 these are just the + + + align:start position:0% +graph so on slide 18 these are just the +oxidation kinetics or oxide thickness + + align:start position:0% +oxidation kinetics or oxide thickness + + + align:start position:0% +oxidation kinetics or oxide thickness +versus time in a wet ambient and I I was + + align:start position:0% +versus time in a wet ambient and I I was + + + align:start position:0% +versus time in a wet ambient and I I was +told we were at a th000 de so that's + + align:start position:0% +told we were at a th000 de so that's + + + align:start position:0% +told we were at a th000 de so that's +this line right here um and we know we + + align:start position:0% +this line right here um and we know we + + + align:start position:0% +this line right here um and we know we +need to grow a point M Micron so that's + + align:start position:0% +need to grow a point M Micron so that's + + + align:start position:0% +need to grow a point M Micron so that's +this uh black line horizontal line and + + align:start position:0% +this uh black line horizontal line and + + + align:start position:0% +this uh black line horizontal line and +you can get it roughly here it's just + + align:start position:0% +you can get it roughly here it's just + + + align:start position:0% +you can get it roughly here it's just +3.8 or so hours depending on how + + align:start position:0% +3.8 or so hours depending on how + + + align:start position:0% +3.8 or so hours depending on how +accurately you can read off the gra off + + align:start position:0% +accurately you can read off the gra off + + + align:start position:0% +accurately you can read off the gra off +the plot if you want to get a little + + align:start position:0% +the plot if you want to get a little + + + align:start position:0% +the plot if you want to get a little +more accurate you go ahead and calculate + + align:start position:0% +more accurate you go ahead and calculate + + + align:start position:0% +more accurate you go ahead and calculate +B and B over a and plug in the equation + + align:start position:0% +B and B over a and plug in the equation + + + align:start position:0% +B and B over a and plug in the equation +but you always check the plot that way + + align:start position:0% +but you always check the plot that way + + + align:start position:0% +but you always check the plot that way +you have you're sure you have a sanity + + align:start position:0% +you have you're sure you have a sanity + + + align:start position:0% +you have you're sure you have a sanity +check that you made didn't make some uh + + align:start position:0% +check that you made didn't make some uh + + + align:start position:0% +check that you made didn't make some uh +calculator mistake or type in the wrong + + align:start position:0% +calculator mistake or type in the wrong + + + align:start position:0% +calculator mistake or type in the wrong +number okay so that's that seems like a + + align:start position:0% +number okay so that's that seems like a + + + align:start position:0% +number okay so that's that seems like a +reasonable um reasonable example of how + + align:start position:0% +reasonable um reasonable example of how + + + align:start position:0% +reasonable um reasonable example of how +you would do um a simple calculation + + align:start position:0% +you would do um a simple calculation + + + align:start position:0% +you would do um a simple calculation +so let's go on now to slide 19 so that + + align:start position:0% +so let's go on now to slide 19 so that + + + align:start position:0% +so let's go on now to slide 19 so that +was a deal Grove model immediately at + + align:start position:0% +was a deal Grove model immediately at + + + align:start position:0% +was a deal Grove model immediately at +the same time deal and Grove published + + align:start position:0% +the same time deal and Grove published + + + align:start position:0% +the same time deal and Grove published +it um they realized that there was a + + align:start position:0% +it um they realized that there was a + + + align:start position:0% +it um they realized that there was a +major problem with the model even when + + align:start position:0% +major problem with the model even when + + + align:start position:0% +major problem with the model even when +it was first proposed um it doesn't + + align:start position:0% +it was first proposed um it doesn't + + + align:start position:0% +it was first proposed um it doesn't +correctly model what they knew to be the + + align:start position:0% +correctly model what they knew to be the + + + align:start position:0% +correctly model what they knew to be the +thin oxide growth kinetics and you can + + align:start position:0% +thin oxide growth kinetics and you can + + + align:start position:0% +thin oxide growth kinetics and you can +see that in this plot this is a plot I + + align:start position:0% +see that in this plot this is a plot I + + + align:start position:0% +see that in this plot this is a plot I +took out of Andy Grove's um book which + + align:start position:0% +took out of Andy Grove's um book which + + + align:start position:0% +took out of Andy Grove's um book which +published quite some time ago but still + + align:start position:0% +published quite some time ago but still + + + align:start position:0% +published quite some time ago but still +a famous book um oxide thickness in + + align:start position:0% +a famous book um oxide thickness in + + + align:start position:0% +a famous book um oxide thickness in +microns as a function of time uh this + + align:start position:0% +microns as a function of time uh this + + + align:start position:0% +microns as a function of time uh this +was this is for a dry oxide grown at 700 + + align:start position:0% +was this is for a dry oxide grown at 700 + + + align:start position:0% +was this is for a dry oxide grown at 700 +very low temperature um and these little + + align:start position:0% +very low temperature um and these little + + + align:start position:0% +very low temperature um and these little +bullets or these open symbols are what + + align:start position:0% +bullets or these open symbols are what + + + align:start position:0% +bullets or these open symbols are what +they measured as the oxide thickness um + + align:start position:0% +they measured as the oxide thickness um + + + align:start position:0% +they measured as the oxide thickness um +and in fact um what they noticed is um + + align:start position:0% +and in fact um what they noticed is um + + + align:start position:0% +and in fact um what they noticed is um +uh that the the model itself which would + + align:start position:0% +uh that the the model itself which would + + + align:start position:0% +uh that the the model itself which would +be in this range um dry the dry oxides + + align:start position:0% +be in this range um dry the dry oxides + + + align:start position:0% +be in this range um dry the dry oxides +grow much faster uh for thicknesses + + align:start position:0% +grow much faster uh for thicknesses + + + align:start position:0% +grow much faster uh for thicknesses +below about um uh 20 nmet or 02 microns + + align:start position:0% +below about um uh 20 nmet or 02 microns + + + align:start position:0% +below about um uh 20 nmet or 02 microns +than predicted by the linear parabolic + + align:start position:0% +than predicted by the linear parabolic + + + align:start position:0% +than predicted by the linear parabolic +uh uh uh model so the linear parabolic + + align:start position:0% +uh uh uh model so the linear parabolic + + + align:start position:0% +uh uh uh model so the linear parabolic +model would have had them you know sort + + align:start position:0% +model would have had them you know sort + + + align:start position:0% +model would have had them you know sort +of going like this and here these oxides + + align:start position:0% +of going like this and here these oxides + + + align:start position:0% +of going like this and here these oxides +are already going up much faster so a + + align:start position:0% +are already going up much faster so a + + + align:start position:0% +are already going up much faster so a +rapid initial oxidation phase which do + + align:start position:0% +rapid initial oxidation phase which do + + + align:start position:0% +rapid initial oxidation phase which do +not take into account when you have a + + align:start position:0% +not take into account when you have a + + + align:start position:0% +not take into account when you have a +linear model in the beginning and then a + + align:start position:0% +linear model in the beginning and then a + + + align:start position:0% +linear model in the beginning and then a +parabolic model so uh people knew right + + align:start position:0% +parabolic model so uh people knew right + + + align:start position:0% +parabolic model so uh people knew right +off that this this really wasn't going + + align:start position:0% +off that this this really wasn't going + + + align:start position:0% +off that this this really wasn't going +to model the initial oxidation kinetics + + align:start position:0% +to model the initial oxidation kinetics + + + align:start position:0% +to model the initial oxidation kinetics +uh very + + align:start position:0% + + + + align:start position:0% + +well so if we can go on to slide 20 then + + align:start position:0% +well so if we can go on to slide 20 then + + + align:start position:0% +well so if we can go on to slide 20 then +um since that time there's been a number + + align:start position:0% +um since that time there's been a number + + + align:start position:0% +um since that time there's been a number +of people have uh uh made suggestions to + + align:start position:0% +of people have uh uh made suggestions to + + + align:start position:0% +of people have uh uh made suggestions to +explain why the initial kinetics are + + align:start position:0% +explain why the initial kinetics are + + + align:start position:0% +explain why the initial kinetics are +faster than what deal and growth uh + + align:start position:0% +faster than what deal and growth uh + + + align:start position:0% +faster than what deal and growth uh +model would predict uh there isn't + + align:start position:0% +model would predict uh there isn't + + + align:start position:0% +model would predict uh there isn't +really one model that's widely uh + + align:start position:0% +really one model that's widely uh + + + align:start position:0% +really one model that's widely uh +totally always accepted um there's a + + align:start position:0% +totally always accepted um there's a + + + align:start position:0% +totally always accepted um there's a +couple of them that that are used in + + align:start position:0% +couple of them that that are used in + + + align:start position:0% +couple of them that that are used in +simulators today so if you go to the + + align:start position:0% +simulators today so if you go to the + + + align:start position:0% +simulators today so if you go to the +Supreme 4 manual and you read up about + + align:start position:0% +Supreme 4 manual and you read up about + + + align:start position:0% +Supreme 4 manual and you read up about +what thin oxide models are available for + + align:start position:0% +what thin oxide models are available for + + + align:start position:0% +what thin oxide models are available for +you to use in your numerical simulations + + align:start position:0% +you to use in your numerical simulations + + + align:start position:0% +you to use in your numerical simulations +here's an example of three of + + align:start position:0% +here's an example of three of + + + align:start position:0% +here's an example of three of +them uh there's the rean model uh Han + + align:start position:0% +them uh there's the rean model uh Han + + + align:start position:0% +them uh there's the rean model uh Han +and Helms and the massud model um so I + + align:start position:0% +and Helms and the massud model um so I + + + align:start position:0% +and Helms and the massud model um so I +want to go through these three they're + + align:start position:0% +want to go through these three they're + + + align:start position:0% +want to go through these three they're +maybe um maybe the most popular or well + + align:start position:0% +maybe um maybe the most popular or well + + + align:start position:0% +maybe um maybe the most popular or well +known of all the + + align:start position:0% + + + + align:start position:0% + +proposals so on slide 21 we have the + + align:start position:0% +proposals so on slide 21 we have the + + + align:start position:0% +proposals so on slide 21 we have the +raceman model um and uh this uh they + + align:start position:0% +raceman model um and uh this uh they + + + align:start position:0% +raceman model um and uh this uh they +they actually proposed a relatively + + align:start position:0% +they actually proposed a relatively + + + align:start position:0% +they actually proposed a relatively +simple power law but it's it seems in + + align:start position:0% +simple power law but it's it seems in + + + align:start position:0% +simple power law but it's it seems in +some people regarded as more of a + + align:start position:0% +some people regarded as more of a + + + align:start position:0% +some people regarded as more of a +mathematical fit uh that quote unquote + + align:start position:0% +mathematical fit uh that quote unquote + + + align:start position:0% +mathematical fit uh that quote unquote +fits the data for dry O2 over a wide + + align:start position:0% +fits the data for dry O2 over a wide + + + align:start position:0% +fits the data for dry O2 over a wide +range of thicknesses and so their power + + align:start position:0% +range of thicknesses and so their power + + + align:start position:0% +range of thicknesses and so their power +law um is actually looks different from + + align:start position:0% +law um is actually looks different from + + + align:start position:0% +law um is actually looks different from +the deal Grove model they say the oxide + + align:start position:0% +the deal Grove model they say the oxide + + + align:start position:0% +the deal Grove model they say the oxide +thickness X not is some constant a Time + + align:start position:0% +thickness X not is some constant a Time + + + align:start position:0% +thickness X not is some constant a Time +t plus ti ti is the initial oxide um + + align:start position:0% +t plus ti ti is the initial oxide um + + + align:start position:0% +t plus ti ti is the initial oxide um +thickness or time equivalent to uh + + align:start position:0% +thickness or time equivalent to uh + + + align:start position:0% +thickness or time equivalent to uh +corresponding to uh the initial oxide to + + align:start position:0% +corresponding to uh the initial oxide to + + + align:start position:0% +corresponding to uh the initial oxide to +the B + + align:start position:0% +the B + + + align:start position:0% +the B +power um or you can uh you know + + align:start position:0% +power um or you can uh you know + + + align:start position:0% +power um or you can uh you know +rearrange it so it looks something like + + align:start position:0% +rearrange it so it looks something like + + + align:start position:0% +rearrange it so it looks something like +this in terms of A and B uh + + align:start position:0% +this in terms of A and B uh + + + align:start position:0% +this in terms of A and B uh +look at this compared to deal Grove you + + align:start position:0% +look at this compared to deal Grove you + + + align:start position:0% +look at this compared to deal Grove you +can see it is actually um it is actually + + align:start position:0% +can see it is actually um it is actually + + + align:start position:0% +can see it is actually um it is actually +uh quite different um although they + + align:start position:0% +uh quite different um although they + + + align:start position:0% +uh quite different um although they +still have a couple of constants they + + align:start position:0% +still have a couple of constants they + + + align:start position:0% +still have a couple of constants they +have a little a a lowercase a and a + + align:start position:0% +have a little a a lowercase a and a + + + align:start position:0% +have a little a a lowercase a and a +lowercase b uh for a given set of + + align:start position:0% +lowercase b uh for a given set of + + + align:start position:0% +lowercase b uh for a given set of +process conditions so similar to deal + + align:start position:0% +process conditions so similar to deal + + + align:start position:0% +process conditions so similar to deal +Grove you have two constants they're + + align:start position:0% +Grove you have two constants they're + + + align:start position:0% +Grove you have two constants they're +different numbers um this actually works + + align:start position:0% +different numbers um this actually works + + + align:start position:0% +different numbers um this actually works +the fit mathematically fits better in + + align:start position:0% +the fit mathematically fits better in + + + align:start position:0% +the fit mathematically fits better in +the thin oxide regime um the problem is + + align:start position:0% +the thin oxide regime um the problem is + + + align:start position:0% +the thin oxide regime um the problem is +it's not as it's not as uh appealing in + + align:start position:0% +it's not as it's not as uh appealing in + + + align:start position:0% +it's not as it's not as uh appealing in +sense of it's not as quite as simple + + align:start position:0% +sense of it's not as quite as simple + + + align:start position:0% +sense of it's not as quite as simple +deal Grove uh but they their physical uh + + align:start position:0% +deal Grove uh but they their physical uh + + + align:start position:0% +deal Grove uh but they their physical uh +reasoning was that the interface + + align:start position:0% +reasoning was that the interface + + + align:start position:0% +reasoning was that the interface +reaction controls the oxidation process + + align:start position:0% +reaction controls the oxidation process + + + align:start position:0% +reaction controls the oxidation process +at all times this is what they thought + + align:start position:0% +at all times this is what they thought + + + align:start position:0% +at all times this is what they thought +um but they believe that this volume + + align:start position:0% +um but they believe that this volume + + + align:start position:0% +um but they believe that this volume +expansion the need for the volume + + align:start position:0% +expansion the need for the volume + + + align:start position:0% +expansion the need for the volume +expansion and and the flow of the oxide + + align:start position:0% +expansion and and the flow of the oxide + + + align:start position:0% +expansion and and the flow of the oxide +the interface control the the um growth + + align:start position:0% +the interface control the the um growth + + + align:start position:0% +the interface control the the um growth +uh kinetics the rate and a and b were + + align:start position:0% +uh kinetics the rate and a and b were + + + align:start position:0% +uh kinetics the rate and a and b were +believed to be some time dependent flow + + align:start position:0% +believed to be some time dependent flow + + + align:start position:0% +believed to be some time dependent flow +parameters for the oxide so uh not as + + align:start position:0% +parameters for the oxide so uh not as + + + align:start position:0% +parameters for the oxide so uh not as +obvious or as simple appealing as the + + align:start position:0% +obvious or as simple appealing as the + + + align:start position:0% +obvious or as simple appealing as the +simple deal Grove model but but they + + align:start position:0% +simple deal Grove model but but they + + + align:start position:0% +simple deal Grove model but but they +also uh found that mathematically it + + align:start position:0% +also uh found that mathematically it + + + align:start position:0% +also uh found that mathematically it +just makes a better + + align:start position:0% +just makes a better + + + align:start position:0% +just makes a better +fit so people do um sometimes use this + + align:start position:0% +fit so people do um sometimes use this + + + align:start position:0% +fit so people do um sometimes use this +type of model and and then fit their own + + align:start position:0% +type of model and and then fit their own + + + align:start position:0% +type of model and and then fit their own +data with their own A and B + + align:start position:0% + + + + align:start position:0% + +constants so that's the the reesman + + align:start position:0% +constants so that's the the reesman + + + align:start position:0% +constants so that's the the reesman +model um H and Helms came along and got + + align:start position:0% +model um H and Helms came along and got + + + align:start position:0% +model um H and Helms came along and got +uh uh additional data and they actually + + align:start position:0% +uh uh additional data and they actually + + + align:start position:0% +uh uh additional data and they actually +said this they actually said that there + + align:start position:0% +said this they actually said that there + + + align:start position:0% +said this they actually said that there +are two in parallel a couple of + + align:start position:0% +are two in parallel a couple of + + + align:start position:0% +are two in parallel a couple of +different oxidation processes taking + + align:start position:0% +different oxidation processes taking + + + align:start position:0% +different oxidation processes taking +place um uh in the model so perhaps they + + align:start position:0% +place um uh in the model so perhaps they + + + align:start position:0% +place um uh in the model so perhaps they +said not only o2 molecules but oxygen + + align:start position:0% +said not only o2 molecules but oxygen + + + align:start position:0% +said not only o2 molecules but oxygen +atoms can diffuse through the oxide + + align:start position:0% +atoms can diffuse through the oxide + + + align:start position:0% +atoms can diffuse through the oxide +maybe in + + align:start position:0% +maybe in + + + align:start position:0% +maybe in +parallel or maybe there's diffusion of + + align:start position:0% +parallel or maybe there's diffusion of + + + align:start position:0% +parallel or maybe there's diffusion of +oxygen vacancies and so you have + + align:start position:0% +oxygen vacancies and so you have + + + align:start position:0% +oxygen vacancies and so you have +something diffusing in and something + + align:start position:0% +something diffusing in and something + + + align:start position:0% +something diffusing in and something +else diffusing out and nevertheless they + + align:start position:0% +else diffusing out and nevertheless they + + + align:start position:0% +else diffusing out and nevertheless they +said there are two species that you need + + align:start position:0% +said there are two species that you need + + + align:start position:0% +said there are two species that you need +to take into account uh and these can + + align:start position:0% +to take into account uh and these can + + + align:start position:0% +to take into account uh and these can +cause re and they have Associated + + align:start position:0% +cause re and they have Associated + + + align:start position:0% +cause re and they have Associated +reactions uh at the interfaces so it + + align:start position:0% +reactions uh at the interfaces so it + + + align:start position:0% +reactions uh at the interfaces so it +looks very much like deal Grove fact + + align:start position:0% +looks very much like deal Grove fact + + + align:start position:0% +looks very much like deal Grove fact +this is deal Grove if you express deal + + align:start position:0% +this is deal Grove if you express deal + + + align:start position:0% +this is deal Grove if you express deal +Grove remember in terms of an oxidation + + align:start position:0% +Grove remember in terms of an oxidation + + + align:start position:0% +Grove remember in terms of an oxidation +rate it's just B / 2 X plus a this looks + + align:start position:0% +rate it's just B / 2 X plus a this looks + + + align:start position:0% +rate it's just B / 2 X plus a this looks +a lot like deal grow but they've added a + + align:start position:0% +a lot like deal grow but they've added a + + + align:start position:0% +a lot like deal grow but they've added a +second term and this this second term + + align:start position:0% +second term and this this second term + + + align:start position:0% +second term and this this second term +here is to correspond to that second + + align:start position:0% +here is to correspond to that second + + + align:start position:0% +here is to correspond to that second +oxidation uh oxidation process happening + + align:start position:0% +oxidation uh oxidation process happening + + + align:start position:0% +oxidation uh oxidation process happening +in + + align:start position:0% +in + + + align:start position:0% +in +parallel and they proposed that all rate + + align:start position:0% +parallel and they proposed that all rate + + + align:start position:0% +parallel and they proposed that all rate +constants would be of an arous type + + align:start position:0% +constants would be of an arous type + + + align:start position:0% +constants would be of an arous type +nature based on the data that they they + + align:start position:0% +nature based on the data that they they + + + align:start position:0% +nature based on the data that they they +fit uh it's just like deal Grove but in + + align:start position:0% +fit uh it's just like deal Grove but in + + + align:start position:0% +fit uh it's just like deal Grove but in +fact they um so you say well you double + + align:start position:0% +fact they um so you say well you double + + + align:start position:0% +fact they um so you say well you double +you should double the number of + + align:start position:0% +you should double the number of + + + align:start position:0% +you should double the number of +constants on Deal Grove so instead of + + align:start position:0% +constants on Deal Grove so instead of + + + align:start position:0% +constants on Deal Grove so instead of +two you should have four in fact what + + align:start position:0% +two you should have four in fact what + + + align:start position:0% +two you should have four in fact what +they found they only really needed three + + align:start position:0% +they found they only really needed three + + + align:start position:0% +they found they only really needed three +parameters to fit the data so they + + align:start position:0% +parameters to fit the data so they + + + align:start position:0% +parameters to fit the data so they +needed a B1 associated with this process + + align:start position:0% +needed a B1 associated with this process + + + align:start position:0% +needed a B1 associated with this process +uh and a B2 associated with this process + + align:start position:0% +uh and a B2 associated with this process + + + align:start position:0% +uh and a B2 associated with this process +and B2 over A2 so they found A1 equal to + + align:start position:0% +and B2 over A2 so they found A1 equal to + + + align:start position:0% +and B2 over A2 so they found A1 equal to +roughly + + align:start position:0% +roughly + + + align:start position:0% +roughly +zero so those of you who are + + align:start position:0% +zero so those of you who are + + + align:start position:0% +zero so those of you who are +skeptical uh in the audience will say + + align:start position:0% +skeptical uh in the audience will say + + + align:start position:0% +skeptical uh in the audience will say +well okay The Grove had two uh two + + align:start position:0% +well okay The Grove had two uh two + + + align:start position:0% +well okay The Grove had two uh two +parameters and Han and Helms have three + + align:start position:0% +parameters and Han and Helms have three + + + align:start position:0% +parameters and Han and Helms have three +so you can if you add more and more + + align:start position:0% +so you can if you add more and more + + + align:start position:0% +so you can if you add more and more +parameters to a fit you can always do a + + align:start position:0% +parameters to a fit you can always do a + + + align:start position:0% +parameters to a fit you can always do a +better job mathematically of fitting + + align:start position:0% +better job mathematically of fitting + + + align:start position:0% +better job mathematically of fitting +data everybody kind of knows that from + + align:start position:0% +data everybody kind of knows that from + + + align:start position:0% +data everybody kind of knows that from +your mathematical experience so you + + align:start position:0% +your mathematical experience so you + + + align:start position:0% +your mathematical experience so you +could be skeptical and say all right + + align:start position:0% +could be skeptical and say all right + + + align:start position:0% +could be skeptical and say all right +they just add another constant and and + + align:start position:0% +they just add another constant and and + + + align:start position:0% +they just add another constant and and +perhaps that's true because the truth is + + align:start position:0% +perhaps that's true because the truth is + + + align:start position:0% +perhaps that's true because the truth is +there isn't really + + align:start position:0% +there isn't really + + + align:start position:0% +there isn't really +any you know definitive data saying what + + align:start position:0% +any you know definitive data saying what + + + align:start position:0% +any you know definitive data saying what +the species are that are diffusing + + align:start position:0% +the species are that are diffusing + + + align:start position:0% +the species are that are diffusing +through there um but nevertheless they + + align:start position:0% +through there um but nevertheless they + + + align:start position:0% +through there um but nevertheless they +did come up with a model that's + + align:start position:0% +did come up with a model that's + + + align:start position:0% +did come up with a model that's +reasonably simple that does a better job + + align:start position:0% +reasonably simple that does a better job + + + align:start position:0% +reasonably simple that does a better job +in the thin oxide uh + + align:start position:0% + + + + align:start position:0% + +kinetics so actually let's compare these + + align:start position:0% +kinetics so actually let's compare these + + + align:start position:0% +kinetics so actually let's compare these +two models uh just on slide 23 with a + + align:start position:0% +two models uh just on slide 23 with a + + + align:start position:0% +two models uh just on slide 23 with a +deal Grove model + + align:start position:0% +deal Grove model + + + align:start position:0% +deal Grove model +so the x-axis here is oxide thickness + + align:start position:0% +so the x-axis here is oxide thickness + + + align:start position:0% +so the x-axis here is oxide thickness +and microns um and this is th uh I'm + + align:start position:0% +and microns um and this is th uh I'm + + + align:start position:0% +and microns um and this is th uh I'm +sorry the y axis is thickness the x-axis + + align:start position:0% +sorry the y axis is thickness the x-axis + + + align:start position:0% +sorry the y axis is thickness the x-axis +this time and this is plotted for um + + align:start position:0% +this time and this is plotted for um + + + align:start position:0% +this time and this is plotted for um +atmospheric pressure dry O2 at + + align:start position:0% +atmospheric pressure dry O2 at + + + align:start position:0% +atmospheric pressure dry O2 at +800° and so let's look at the the the + + align:start position:0% +800° and so let's look at the the the + + + align:start position:0% +800° and so let's look at the the the +different models this line right here + + align:start position:0% +different models this line right here + + + align:start position:0% +different models this line right here +unfortunately they're all the same color + + align:start position:0% +unfortunately they're all the same color + + + align:start position:0% +unfortunately they're all the same color +I apologize but you can sort of see + + align:start position:0% +I apologize but you can sort of see + + + align:start position:0% +I apologize but you can sort of see +where the arrow is pointing to the rean + + align:start position:0% +where the arrow is pointing to the rean + + + align:start position:0% +where the arrow is pointing to the rean +model um look something like this H and + + align:start position:0% +model um look something like this H and + + + align:start position:0% +model um look something like this H and +Helms amazingly you know different + + align:start position:0% +Helms amazingly you know different + + + align:start position:0% +Helms amazingly you know different +mathematical equations but they look + + align:start position:0% +mathematical equations but they look + + + align:start position:0% +mathematical equations but they look +pretty darn close they're not exactly on + + align:start position:0% +pretty darn close they're not exactly on + + + align:start position:0% +pretty darn close they're not exactly on +top of each other in this thin oxide + + align:start position:0% +top of each other in this thin oxide + + + align:start position:0% +top of each other in this thin oxide +machinee but they're pretty darn close + + align:start position:0% +machinee but they're pretty darn close + + + align:start position:0% +machinee but they're pretty darn close +uh the deal Grove model with t equals + + align:start position:0% +uh the deal Grove model with t equals + + + align:start position:0% +uh the deal Grove model with t equals +Zer looks like this and withal equals 8 + + align:start position:0% +Zer looks like this and withal equals 8 + + + align:start position:0% +Zer looks like this and withal equals 8 +looks like that doesn't actually + + align:start position:0% +looks like that doesn't actually + + + align:start position:0% +looks like that doesn't actually +approach e either one of them very well + + align:start position:0% +approach e either one of them very well + + + align:start position:0% +approach e either one of them very well +until you get into the thicker regime up + + align:start position:0% +until you get into the thicker regime up + + + align:start position:0% +until you get into the thicker regime up +here um but in this thin regime say + + align:start position:0% +here um but in this thin regime say + + + align:start position:0% +here um but in this thin regime say +below 200 angstroms or 02 microns uh + + align:start position:0% +below 200 angstroms or 02 microns uh + + + align:start position:0% +below 200 angstroms or 02 microns uh +deal Grove doesn't really approach + + align:start position:0% +deal Grove doesn't really approach + + + align:start position:0% +deal Grove doesn't really approach +either one and and Han and Helms and + + align:start position:0% +either one and and Han and Helms and + + + align:start position:0% +either one and and Han and Helms and +Raisman do actually approach the data + + align:start position:0% +Raisman do actually approach the data + + + align:start position:0% +Raisman do actually approach the data +quite quite well they will converge + + align:start position:0% +quite quite well they will converge + + + align:start position:0% +quite quite well they will converge +though when you get oxides thicker than + + align:start position:0% +though when you get oxides thicker than + + + align:start position:0% +though when you get oxides thicker than + + align:start position:0% + + + align:start position:0% +angstroms there's one more model that + + align:start position:0% +angstroms there's one more model that + + + align:start position:0% +angstroms there's one more model that +people actually uh are very uh are very + + align:start position:0% +people actually uh are very uh are very + + + align:start position:0% +people actually uh are very uh are very +fond of and I'll talk about that now + + align:start position:0% +fond of and I'll talk about that now + + + align:start position:0% +fond of and I'll talk about that now +that's shown on slide 24 this was the um + + align:start position:0% +that's shown on slide 24 this was the um + + + align:start position:0% +that's shown on slide 24 this was the um +the massud model this was published + + align:start position:0% +the massud model this was published + + + align:start position:0% +the massud model this was published +quite some time ago at the + + align:start position:0% +quite some time ago at the + + + align:start position:0% +quite some time ago at the +electrochemical society and the nice + + align:start position:0% +electrochemical society and the nice + + + align:start position:0% +electrochemical society and the nice +thing about H the neat thing about uh + + align:start position:0% +thing about H the neat thing about uh + + + align:start position:0% +thing about H the neat thing about uh +Mass's experiment was they actually + + align:start position:0% +Mass's experiment was they actually + + + align:start position:0% +Mass's experiment was they actually +measured in in + + align:start position:0% +measured in in + + + align:start position:0% +measured in in +situ you know in the furnace they + + align:start position:0% +situ you know in the furnace they + + + align:start position:0% +situ you know in the furnace they +actually measured the thickness uh of + + align:start position:0% +actually measured the thickness uh of + + + align:start position:0% +actually measured the thickness uh of +the oxide growing as a function of time + + align:start position:0% +the oxide growing as a function of time + + + align:start position:0% +the oxide growing as a function of time +so the other people like deal Grove and + + align:start position:0% +so the other people like deal Grove and + + + align:start position:0% +so the other people like deal Grove and +and Han and Helms all those people you + + align:start position:0% +and Han and Helms all those people you + + + align:start position:0% +and Han and Helms all those people you +know they put a couple wafers in and + + align:start position:0% +know they put a couple wafers in and + + + align:start position:0% +know they put a couple wafers in and +take them out you know put them in for + + align:start position:0% +take them out you know put them in for + + + align:start position:0% +take them out you know put them in for +different amounts of time and so they + + align:start position:0% +different amounts of time and so they + + + align:start position:0% +different amounts of time and so they +get a few certain data points you know + + align:start position:0% +get a few certain data points you know + + + align:start position:0% +get a few certain data points you know +how many Wafers can you put in maybe + + align:start position:0% +how many Wafers can you put in maybe + + + align:start position:0% +how many Wafers can you put in maybe +five or 10 in an experiment so you can't + + align:start position:0% +five or 10 in an experiment so you can't + + + align:start position:0% +five or 10 in an experiment so you can't +really measure the kinetics in in great + + align:start position:0% +really measure the kinetics in in great + + + align:start position:0% +really measure the kinetics in in great +detail uh if you're just pushing pulling + + align:start position:0% +detail uh if you're just pushing pulling + + + align:start position:0% +detail uh if you're just pushing pulling +Wafers out of the furnace and just + + align:start position:0% +Wafers out of the furnace and just + + + align:start position:0% +Wafers out of the furnace and just +measuring them outside what massud + + align:start position:0% +measuring them outside what massud + + + align:start position:0% +measuring them outside what massud +decided to do to study the very thin + + align:start position:0% +decided to do to study the very thin + + + align:start position:0% +decided to do to study the very thin +regime + + align:start position:0% +regime + + + align:start position:0% +regime +uh was actually set up and it was + + align:start position:0% +uh was actually set up and it was + + + align:start position:0% +uh was actually set up and it was +non-trivial he had a diffusion furnace + + align:start position:0% +non-trivial he had a diffusion furnace + + + align:start position:0% +non-trivial he had a diffusion furnace +had special Windows placed into it where + + align:start position:0% +had special Windows placed into it where + + + align:start position:0% +had special Windows placed into it where +he could put laser beam so you could put + + align:start position:0% +he could put laser beam so you could put + + + align:start position:0% +he could put laser beam so you could put +a laser beam coming in laser beam coming + + align:start position:0% +a laser beam coming in laser beam coming + + + align:start position:0% +a laser beam coming in laser beam coming +out and he could do insitu measurements + + align:start position:0% +out and he could do insitu measurements + + + align:start position:0% +out and he could do insitu measurements +by + + align:start position:0% +by + + + align:start position:0% +by +ellipsometry um of the oxidate oxide out + + align:start position:0% +ellipsometry um of the oxidate oxide out + + + align:start position:0% +ellipsometry um of the oxidate oxide out +as it was growing in the tube it doesn't + + align:start position:0% +as it was growing in the tube it doesn't + + + align:start position:0% +as it was growing in the tube it doesn't +you it doesn't sound like a big deal but + + align:start position:0% +you it doesn't sound like a big deal but + + + align:start position:0% +you it doesn't sound like a big deal but +it turns out it's it's pretty uh + + align:start position:0% +it turns out it's it's pretty uh + + + align:start position:0% +it turns out it's it's pretty uh +challenging because there's all kinds of + + align:start position:0% +challenging because there's all kinds of + + + align:start position:0% +challenging because there's all kinds of +thermal expansion going on and the wafer + + align:start position:0% +thermal expansion going on and the wafer + + + align:start position:0% +thermal expansion going on and the wafer +has to sit still and not move while this + + align:start position:0% +has to sit still and not move while this + + + align:start position:0% +has to sit still and not move while this +laser comes in hits and bounces off + + align:start position:0% +laser comes in hits and bounces off + + + align:start position:0% +laser comes in hits and bounces off +because in ellip omry the angle of + + align:start position:0% +because in ellip omry the angle of + + + align:start position:0% +because in ellip omry the angle of +incidence is very important and all that + + align:start position:0% +incidence is very important and all that + + + align:start position:0% +incidence is very important and all that +so designing the equipment was like a + + align:start position:0% +so designing the equipment was like a + + + align:start position:0% +so designing the equipment was like a +huge part of this PhD faces uh but it + + align:start position:0% +huge part of this PhD faces uh but it + + + align:start position:0% +huge part of this PhD faces uh but it +the nice thing is it did produce a lot + + align:start position:0% +the nice thing is it did produce a lot + + + align:start position:0% +the nice thing is it did produce a lot +of data look at all these data points + + align:start position:0% +of data look at all these data points + + + align:start position:0% +of data look at all these data points +they're all basically give you a nice + + align:start position:0% +they're all basically give you a nice + + + align:start position:0% +they're all basically give you a nice +looking curve instead of one point here + + align:start position:0% +looking curve instead of one point here + + + align:start position:0% +looking curve instead of one point here +one here and one here uh he published um + + align:start position:0% +one here and one here uh he published um + + + align:start position:0% +one here and one here uh he published um +measured Inu measured oxidation rates + + align:start position:0% +measured Inu measured oxidation rates + + + align:start position:0% +measured Inu measured oxidation rates +now this is the rate so this is not the + + align:start position:0% +now this is the rate so this is not the + + + align:start position:0% +now this is the rate so this is not the +thickness this is angstroms per + + align:start position:0% +thickness this is angstroms per + + + align:start position:0% +thickness this is angstroms per +minute uh as a function of the thickness + + align:start position:0% +minute uh as a function of the thickness + + + align:start position:0% +minute uh as a function of the thickness +grown and indeed look below 200 + + align:start position:0% +grown and indeed look below 200 + + + align:start position:0% +grown and indeed look below 200 +angstroms um all these rates are much + + align:start position:0% +angstroms um all these rates are much + + + align:start position:0% +angstroms um all these rates are much +larger than they are uh where they they + + align:start position:0% +larger than they are uh where they they + + + align:start position:0% +larger than they are uh where they they +they reach steady state they reach + + align:start position:0% +they reach steady state they reach + + + align:start position:0% +they reach steady state they reach +smaller uh rates and these are at three + + align:start position:0% +smaller uh rates and these are at three + + + align:start position:0% +smaller uh rates and these are at three +different temperatures 800 900 and a + + align:start position:0% +different temperatures 800 900 and a + + + align:start position:0% +different temperatures 800 900 and a +th000 and in the thin oxide regime the + + align:start position:0% +th000 and in the thin oxide regime the + + + align:start position:0% +th000 and in the thin oxide regime the +rate itself appears to be going up + + align:start position:0% +rate itself appears to be going up + + + align:start position:0% +rate itself appears to be going up +exponentially uh as you get to thinner + + align:start position:0% +exponentially uh as you get to thinner + + + align:start position:0% +exponentially uh as you get to thinner +and thinner which are shorter and + + align:start position:0% +and thinner which are shorter and + + + align:start position:0% +and thinner which are shorter and +shorter times so interestingly initially + + align:start position:0% +shorter times so interestingly initially + + + align:start position:0% +shorter times so interestingly initially +it appears to be in fact an exponential + + align:start position:0% +it appears to be in fact an exponential + + + align:start position:0% +it appears to be in fact an exponential +process with time so it's growing very + + align:start position:0% +process with time so it's growing very + + + align:start position:0% +process with time so it's growing very +rapidly uh and then it starts to + + align:start position:0% +rapidly uh and then it starts to + + + align:start position:0% +rapidly uh and then it starts to +converge to a process that looks going + + align:start position:0% +converge to a process that looks going + + + align:start position:0% +converge to a process that looks going +to look more linear and then eventually + + align:start position:0% +to look more linear and then eventually + + + align:start position:0% +to look more linear and then eventually +parabolic only with that kind of special + + align:start position:0% +parabolic only with that kind of special + + + align:start position:0% +parabolic only with that kind of special +apparatus could one get enough data + + align:start position:0% +apparatus could one get enough data + + + align:start position:0% +apparatus could one get enough data +point density to really see that though + + align:start position:0% +point density to really see that though + + + align:start position:0% +point density to really see that though +so this is probably the most um + + align:start position:0% +so this is probably the most um + + + align:start position:0% +so this is probably the most um +extensive experimental study that has + + align:start position:0% +extensive experimental study that has + + + align:start position:0% +extensive experimental study that has +been + + align:start position:0% +been + + + align:start position:0% +been +done um and what he did was he took deal + + align:start position:0% +done um and what he did was he took deal + + + align:start position:0% +done um and what he did was he took deal +grow just as it as it came right out of + + align:start position:0% +grow just as it as it came right out of + + + align:start position:0% +grow just as it as it came right out of +the box and added one more term but the + + align:start position:0% +the box and added one more term but the + + + align:start position:0% +the box and added one more term but the +term was exponential in + + align:start position:0% +term was exponential in + + + align:start position:0% +term was exponential in +thickness so the oxidation rate had the + + align:start position:0% +thickness so the oxidation rate had the + + + align:start position:0% +thickness so the oxidation rate had the +deal Grove B / 2x KN plus a plus a term + + align:start position:0% +deal Grove B / 2x KN plus a plus a term + + + align:start position:0% +deal Grove B / 2x KN plus a plus a term +that went like C * exponential of minus + + align:start position:0% +that went like C * exponential of minus + + + align:start position:0% +that went like C * exponential of minus +x l so what is this this mathematically + + align:start position:0% +x l so what is this this mathematically + + + align:start position:0% +x l so what is this this mathematically +this is a decaying exponential when L + + align:start position:0% +this is a decaying exponential when L + + + align:start position:0% +this is a decaying exponential when L +gets very large L is much greater than + + align:start position:0% +gets very large L is much greater than + + + align:start position:0% +gets very large L is much greater than +200 angstroms this this number goes away + + align:start position:0% +200 angstroms this this number goes away + + + align:start position:0% +200 angstroms this this number goes away +right you can always make it go go uh go + + align:start position:0% +right you can always make it go go uh go + + + align:start position:0% +right you can always make it go go uh go +go to be very small compared to this + + align:start position:0% +go to be very small compared to this + + + align:start position:0% +go to be very small compared to this +term so he wanted it all converge to + + align:start position:0% +term so he wanted it all converge to + + + align:start position:0% +term so he wanted it all converge to +deal growth at thick enough oxides but + + align:start position:0% +deal growth at thick enough oxides but + + + align:start position:0% +deal growth at thick enough oxides but +for thin oxides this is going to + + align:start position:0% +for thin oxides this is going to + + + align:start position:0% +for thin oxides this is going to +dominate this C + + align:start position:0% +dominate this C + + + align:start position:0% +dominate this C +term uh and he in order to do that he + + align:start position:0% +term uh and he in order to do that he + + + align:start position:0% +term uh and he in order to do that he +had to choose L to be a certain number + + align:start position:0% +had to choose L to be a certain number + + + align:start position:0% +had to choose L to be a certain number +so that had the right Decay length and + + align:start position:0% +so that had the right Decay length and + + + align:start position:0% +so that had the right Decay length and +and L he found experimentally should be + + align:start position:0% +and L he found experimentally should be + + + align:start position:0% +and L he found experimentally should be +about 7 nmet so that the second term + + align:start position:0% +about 7 nmet so that the second term + + + align:start position:0% +about 7 nmet so that the second term +will Decay rapidly enough uh by the time + + align:start position:0% +will Decay rapidly enough uh by the time + + + align:start position:0% +will Decay rapidly enough uh by the time +you get to um 20 nmet or + + align:start position:0% +you get to um 20 nmet or + + + align:start position:0% +you get to um 20 nmet or +so um in fact this this model does agree + + align:start position:0% +so um in fact this this model does agree + + + align:start position:0% +so um in fact this this model does agree +very well mathematically with + + align:start position:0% +very well mathematically with + + + align:start position:0% +very well mathematically with +experimental data um it's actually very + + align:start position:0% +experimental data um it's actually very + + + align:start position:0% +experimental data um it's actually very +easy to implement in simulators like + + align:start position:0% +easy to implement in simulators like + + + align:start position:0% +easy to implement in simulators like +Supreme 4 and so you will it it has been + + align:start position:0% +Supreme 4 and so you will it it has been + + + align:start position:0% +Supreme 4 and so you will it it has been +found to be implemented in Supreme 4 and + + align:start position:0% +found to be implemented in Supreme 4 and + + + align:start position:0% +found to be implemented in Supreme 4 and +um uh in terms of physical explanations + + align:start position:0% +um uh in terms of physical explanations + + + align:start position:0% +um uh in terms of physical explanations +there's there's a few that have come out + + align:start position:0% +there's there's a few that have come out + + + align:start position:0% +there's there's a few that have come out +but none has really been clearly + + align:start position:0% +but none has really been clearly + + + align:start position:0% +but none has really been clearly +identified as being the right reason uh + + align:start position:0% +identified as being the right reason uh + + + align:start position:0% +identified as being the right reason uh +so for now we use it as sort of a + + align:start position:0% +so for now we use it as sort of a + + + align:start position:0% +so for now we use it as sort of a +mathematical model or an empirical + + align:start position:0% +mathematical model or an empirical + + + align:start position:0% +mathematical model or an empirical +relation um it's very handy and it can + + align:start position:0% +relation um it's very handy and it can + + + align:start position:0% +relation um it's very handy and it can +be reasonably accurate so it's appealing + + align:start position:0% +be reasonably accurate so it's appealing + + + align:start position:0% +be reasonably accurate so it's appealing +in that sense in terms of the physics + + align:start position:0% +in that sense in terms of the physics + + + align:start position:0% +in that sense in terms of the physics +and the chemistry it's not completely + + align:start position:0% + + + + align:start position:0% + +obvious okay so those are the three thin + + align:start position:0% +obvious okay so those are the three thin + + + align:start position:0% +obvious okay so those are the three thin +oxide models and and hopefully you'll + + align:start position:0% +oxide models and and hopefully you'll + + + align:start position:0% +oxide models and and hopefully you'll +get a chance to study some of those a + + align:start position:0% +get a chance to study some of those a + + + align:start position:0% +get a chance to study some of those a +little bit more in in one of your + + align:start position:0% +little bit more in in one of your + + + align:start position:0% +little bit more in in one of your +homework problems um so now let's let's + + align:start position:0% +homework problems um so now let's let's + + + align:start position:0% +homework problems um so now let's let's +let VAR something else all we varied so + + align:start position:0% +let VAR something else all we varied so + + + align:start position:0% +let VAR something else all we varied so +far is the following we varied the + + align:start position:0% +far is the following we varied the + + + align:start position:0% +far is the following we varied the +ambient uh we said it could be dry O2 or + + align:start position:0% +ambient uh we said it could be dry O2 or + + + align:start position:0% +ambient uh we said it could be dry O2 or +water and temperature what else can you + + align:start position:0% +water and temperature what else can you + + + align:start position:0% +water and temperature what else can you +vary well it it turns out people often + + align:start position:0% +vary well it it turns out people often + + + align:start position:0% +vary well it it turns out people often +do vary the pressure um that is the + + align:start position:0% +do vary the pressure um that is the + + + align:start position:0% +do vary the pressure um that is the +partial pressure of the oxidant if you + + align:start position:0% +partial pressure of the oxidant if you + + + align:start position:0% +partial pressure of the oxidant if you +want to grow a very thin oxide and yet + + align:start position:0% +want to grow a very thin oxide and yet + + + align:start position:0% +want to grow a very thin oxide and yet +you want to grow at a higher temperature + + align:start position:0% +you want to grow at a higher temperature + + + align:start position:0% +you want to grow at a higher temperature +because you want to get different uh + + align:start position:0% +because you want to get different uh + + + align:start position:0% +because you want to get different uh +electrical quality of the interface you + + align:start position:0% +electrical quality of the interface you + + + align:start position:0% +electrical quality of the interface you +can't grow too fast so you might want to + + align:start position:0% +can't grow too fast so you might want to + + + align:start position:0% +can't grow too fast so you might want to +slow it down by diluting you can just + + align:start position:0% +slow it down by diluting you can just + + + align:start position:0% +slow it down by diluting you can just +take the oxygen and flow mostly nitrogen + + align:start position:0% +take the oxygen and flow mostly nitrogen + + + align:start position:0% +take the oxygen and flow mostly nitrogen +and have oxygen flow be a very small + + align:start position:0% +and have oxygen flow be a very small + + + align:start position:0% +and have oxygen flow be a very small +fraction of the gas stream that's a way + + align:start position:0% +fraction of the gas stream that's a way + + + align:start position:0% +fraction of the gas stream that's a way +of diluting the uh the gas stream and + + align:start position:0% +of diluting the uh the gas stream and + + + align:start position:0% +of diluting the uh the gas stream and +growing at lower partial + + align:start position:0% +growing at lower partial + + + align:start position:0% +growing at lower partial +pressures so um just as a reminder um + + align:start position:0% +pressures so um just as a reminder um + + + align:start position:0% +pressures so um just as a reminder um +what it deal grow predicts that the + + align:start position:0% +what it deal grow predicts that the + + + align:start position:0% +what it deal grow predicts that the +oxide growth rate should be directly + + align:start position:0% +oxide growth rate should be directly + + + align:start position:0% +oxide growth rate should be directly +proportional to the pressure of the + + align:start position:0% +proportional to the pressure of the + + + align:start position:0% +proportional to the pressure of the +oxygen C star uh effectively you can + + align:start position:0% +oxygen C star uh effectively you can + + + align:start position:0% +oxygen C star uh effectively you can +think of it um should depend on PG where + + align:start position:0% +think of it um should depend on PG where + + + align:start position:0% +think of it um should depend on PG where +PG is the bulk gas pressure um so um + + align:start position:0% +PG is the bulk gas pressure um so um + + + align:start position:0% +PG is the bulk gas pressure um so um +basically if I were to um lower the gas + + align:start position:0% +basically if I were to um lower the gas + + + align:start position:0% +basically if I were to um lower the gas +pressure um you would expect that you + + align:start position:0% +pressure um you would expect that you + + + align:start position:0% +pressure um you would expect that you +could lower the oxidation rate so just + + align:start position:0% +could lower the oxidation rate so just + + + align:start position:0% +could lower the oxidation rate so just +uh to be a little more specific we go on + + align:start position:0% +uh to be a little more specific we go on + + + align:start position:0% +uh to be a little more specific we go on +to slide + + align:start position:0% +to slide + + + align:start position:0% +to slide +27 what people have found though is it's + + align:start position:0% +27 what people have found though is it's + + + align:start position:0% +27 what people have found though is it's +not completely linear um experimentally + + align:start position:0% +not completely linear um experimentally + + + align:start position:0% +not completely linear um experimentally +if you lower the partial pressure of the + + align:start position:0% +if you lower the partial pressure of the + + + align:start position:0% +if you lower the partial pressure of the +oxidant um in fact B and B over a do + + align:start position:0% +oxidant um in fact B and B over a do + + + align:start position:0% +oxidant um in fact B and B over a do +scale like P where P would be the + + align:start position:0% +scale like P where P would be the + + + align:start position:0% +scale like P where P would be the +partial pressure + + align:start position:0% +partial pressure + + + align:start position:0% +partial pressure +um for uh for water + + align:start position:0% +um for uh for water + + + align:start position:0% +um for uh for water +oxidation and the rate constant B does + + align:start position:0% +oxidation and the rate constant B does + + + align:start position:0% +oxidation and the rate constant B does +scale like the pressure um uh for um dry + + align:start position:0% +scale like the pressure um uh for um dry + + + align:start position:0% +scale like the pressure um uh for um dry +O2 the one rate constant that's + + align:start position:0% +O2 the one rate constant that's + + + align:start position:0% +O2 the one rate constant that's +anomalous is the linear rate constant + + align:start position:0% +anomalous is the linear rate constant + + + align:start position:0% +anomalous is the linear rate constant +the B over a for um dry O2 doesn't go + + align:start position:0% +the B over a for um dry O2 doesn't go + + + align:start position:0% +the B over a for um dry O2 doesn't go +quite like exactly like pressure it goes + + align:start position:0% +quite like exactly like pressure it goes + + + align:start position:0% +quite like exactly like pressure it goes +like P to the N where n is close to one + + align:start position:0% +like P to the N where n is close to one + + + align:start position:0% +like P to the N where n is close to one +but not really one it's somewhere + + align:start position:0% +but not really one it's somewhere + + + align:start position:0% +but not really one it's somewhere +between 0.5 so it's a parallel between + + align:start position:0% +between 0.5 so it's a parallel between + + + align:start position:0% +between 0.5 so it's a parallel between +05 and + + align:start position:0% +05 and + + + align:start position:0% +05 and +one so this suggests that at least for + + align:start position:0% +one so this suggests that at least for + + + align:start position:0% +one so this suggests that at least for +oxid you know case of s maybe has some + + align:start position:0% +oxid you know case of s maybe has some + + + align:start position:0% +oxid you know case of s maybe has some +dependence on pressure uh that's + + align:start position:0% + + + + align:start position:0% + +nonlinear so these are some empirical + + align:start position:0% +nonlinear so these are some empirical + + + align:start position:0% +nonlinear so these are some empirical +models that people that you'll find in + + align:start position:0% +models that people that you'll find in + + + align:start position:0% +models that people that you'll find in +Supreme 4 for example the linear rate + + align:start position:0% +Supreme 4 for example the linear rate + + + align:start position:0% +Supreme 4 for example the linear rate +constant may depend um may go like some + + align:start position:0% +constant may depend um may go like some + + + align:start position:0% +constant may depend um may go like some +some number B over a to the I uh times + + align:start position:0% +some number B over a to the I uh times + + + align:start position:0% +some number B over a to the I uh times +pressure uh where I here refers to the + + align:start position:0% +pressure uh where I here refers to the + + + align:start position:0% +pressure uh where I here refers to the +values intrinsic values at one + + align:start position:0% +values intrinsic values at one + + + align:start position:0% +values intrinsic values at one +atmosphere um n here might be 7 to 08 + + align:start position:0% +atmosphere um n here might be 7 to 08 + + + align:start position:0% +atmosphere um n here might be 7 to 08 +and you notice uh you specify the + + align:start position:0% +and you notice uh you specify the + + + align:start position:0% +and you notice uh you specify the +pressure p so maybe you say at half an + + align:start position:0% +pressure p so maybe you say at half an + + + align:start position:0% +pressure p so maybe you say at half an +atmosphere or a tenth of an atmosphere + + align:start position:0% +atmosphere or a tenth of an atmosphere + + + align:start position:0% +atmosphere or a tenth of an atmosphere +um so but we're not changing think of it + + align:start position:0% +um so but we're not changing think of it + + + align:start position:0% +um so but we're not changing think of it +this way you're not actually changing + + align:start position:0% +this way you're not actually changing + + + align:start position:0% +this way you're not actually changing +the pressure in the tube the pressure of + + align:start position:0% +the pressure in the tube the pressure of + + + align:start position:0% +the pressure in the tube the pressure of +of all the gas in the tube is still an + + align:start position:0% +of all the gas in the tube is still an + + + align:start position:0% +of all the gas in the tube is still an +atmosphere what we're doing is we're + + align:start position:0% +atmosphere what we're doing is we're + + + align:start position:0% +atmosphere what we're doing is we're +flowing mostly nitrogen and we're + + align:start position:0% +flowing mostly nitrogen and we're + + + align:start position:0% +flowing mostly nitrogen and we're +putting a small amount of uh oxygen in + + align:start position:0% +putting a small amount of uh oxygen in + + + align:start position:0% +putting a small amount of uh oxygen in +in the gas stream so that's say I wanted + + align:start position:0% +in the gas stream so that's say I wanted + + + align:start position:0% +in the gas stream so that's say I wanted +to oxidize at half an atmosphere oh I + + align:start position:0% +to oxidize at half an atmosphere oh I + + + align:start position:0% +to oxidize at half an atmosphere oh I +just cut the flow I'd use equal flows of + + align:start position:0% +just cut the flow I'd use equal flows of + + + align:start position:0% +just cut the flow I'd use equal flows of +nitrogen and oxygen so we're we're + + align:start position:0% +nitrogen and oxygen so we're we're + + + align:start position:0% +nitrogen and oxygen so we're we're +diluting uh the the pressure basically + + align:start position:0% +diluting uh the the pressure basically + + + align:start position:0% +diluting uh the the pressure basically +we're diluting the oxiden in the gas + + align:start position:0% +we're diluting the oxiden in the gas + + + align:start position:0% +we're diluting the oxiden in the gas +stream so here's an example suppose I + + align:start position:0% +stream so here's an example suppose I + + + align:start position:0% +stream so here's an example suppose I +dilute it by a factor of 10 to + + align:start position:0% +dilute it by a factor of 10 to + + + align:start position:0% +dilute it by a factor of 10 to +one so I'm flowing a th SCCM of uh inert + + align:start position:0% +one so I'm flowing a th SCCM of uh inert + + + align:start position:0% +one so I'm flowing a th SCCM of uh inert +gas like argon or nitrogen and uh I'm + + align:start position:0% +gas like argon or nitrogen and uh I'm + + + align:start position:0% +gas like argon or nitrogen and uh I'm +I'm flowing only 100 secm of oxygen dro2 + + align:start position:0% +I'm flowing only 100 secm of oxygen dro2 + + + align:start position:0% +I'm flowing only 100 secm of oxygen dro2 +um this is what we would get as the + + align:start position:0% +um this is what we would get as the + + + align:start position:0% +um this is what we would get as the +oxide thickness uh versus + + align:start position:0% +oxide thickness uh versus + + + align:start position:0% +oxide thickness uh versus +time and uh the solid lines were if you + + align:start position:0% +time and uh the solid lines were if you + + + align:start position:0% +time and uh the solid lines were if you +were to do the very Brute Force simple + + align:start position:0% +were to do the very Brute Force simple + + + align:start position:0% +were to do the very Brute Force simple +simple uh idea that it was all scaled + + align:start position:0% +simple uh idea that it was all scaled + + + align:start position:0% +simple uh idea that it was all scaled +like P and uh you know it's just down + + align:start position:0% +like P and uh you know it's just down + + + align:start position:0% +like P and uh you know it's just down +these uh the the um rate constants are + + align:start position:0% +these uh the the um rate constants are + + + align:start position:0% +these uh the the um rate constants are +down by a factor of P where P here would + + align:start position:0% +down by a factor of P where P here would + + + align:start position:0% +down by a factor of P where P here would +be a 1/10th the pressure of atmospheric + + align:start position:0% +be a 1/10th the pressure of atmospheric + + + align:start position:0% +be a 1/10th the pressure of atmospheric +pressure the dash line is where you use + + align:start position:0% +pressure the dash line is where you use + + + align:start position:0% +pressure the dash line is where you use +a little bit more sophisticated model + + align:start position:0% +a little bit more sophisticated model + + + align:start position:0% +a little bit more sophisticated model +where in fact um the B parameter scales + + align:start position:0% +where in fact um the B parameter scales + + + align:start position:0% +where in fact um the B parameter scales +like pressure but the B over a parameter + + align:start position:0% +like pressure but the B over a parameter + + + align:start position:0% +like pressure but the B over a parameter +scales like pressure to point8 so just + + align:start position:0% +scales like pressure to point8 so just + + + align:start position:0% +scales like pressure to point8 so just +slightly so in fact the kinetics would + + align:start position:0% +slightly so in fact the kinetics would + + + align:start position:0% +slightly so in fact the kinetics would +be slightly faster the oxide would be + + align:start position:0% +be slightly faster the oxide would be + + + align:start position:0% +be slightly faster the oxide would be +growing slightly faster than you would + + align:start position:0% +growing slightly faster than you would + + + align:start position:0% +growing slightly faster than you would +have predicted using very simple + + align:start position:0% +have predicted using very simple + + + align:start position:0% +have predicted using very simple +dependence on just saying it depends uh + + align:start position:0% +dependence on just saying it depends uh + + + align:start position:0% +dependence on just saying it depends uh +strictly on P um so it gives you a + + align:start position:0% +strictly on P um so it gives you a + + + align:start position:0% +strictly on P um so it gives you a +little bit more accuracy using some of + + align:start position:0% +little bit more accuracy using some of + + + align:start position:0% +little bit more accuracy using some of +these uh more empirical + + align:start position:0% +these uh more empirical + + + align:start position:0% +these uh more empirical +models but again if you what the idea + + align:start position:0% +models but again if you what the idea + + + align:start position:0% +models but again if you what the idea +here is you need if for some reason we + + align:start position:0% +here is you need if for some reason we + + + align:start position:0% +here is you need if for some reason we +need to control the oxidation rate + + align:start position:0% +need to control the oxidation rate + + + align:start position:0% +need to control the oxidation rate +better you want to slow it down you just + + align:start position:0% +better you want to slow it down you just + + + align:start position:0% +better you want to slow it down you just +dilute the oxygen in the + + align:start position:0% + + + + align:start position:0% + +furnace whoops oh I just showed some + + align:start position:0% +furnace whoops oh I just showed some + + + align:start position:0% +furnace whoops oh I just showed some +specific examples here of trying to read + + align:start position:0% +specific examples here of trying to read + + + align:start position:0% +specific examples here of trying to read +off what difference would be you'd make + + align:start position:0% +off what difference would be you'd make + + + align:start position:0% +off what difference would be you'd make +an error of about a thou 100 angstroms + + align:start position:0% +an error of about a thou 100 angstroms + + + align:start position:0% +an error of about a thou 100 angstroms +uh if you use the simple uh assumption + + align:start position:0% +uh if you use the simple uh assumption + + + align:start position:0% +uh if you use the simple uh assumption +compared to what's a little bit more + + align:start position:0% +compared to what's a little bit more + + + align:start position:0% +compared to what's a little bit more +accurate um here at a th000 + + align:start position:0% + + + + align:start position:0% + +degrees + + align:start position:0% +degrees + + + align:start position:0% +degrees +um okay so let me let me just skip + + align:start position:0% +um okay so let me let me just skip + + + align:start position:0% +um okay so let me let me just skip +through that's uh the standard kinetics + + align:start position:0% +through that's uh the standard kinetics + + + align:start position:0% +through that's uh the standard kinetics +um on slide 29 uh let's go on to slide + + align:start position:0% +um on slide 29 uh let's go on to slide + + + align:start position:0% +um on slide 29 uh let's go on to slide +30 then okay so what I just talked about + + align:start position:0% +30 then okay so what I just talked about + + + align:start position:0% +30 then okay so what I just talked about +was trying to dilute the oxidation the + + align:start position:0% +was trying to dilute the oxidation the + + + align:start position:0% +was trying to dilute the oxidation the +oxidant so you can grow slower at a + + align:start position:0% +oxidant so you can grow slower at a + + + align:start position:0% +oxidant so you can grow slower at a +given temperature um on slide 30 we're + + align:start position:0% +given temperature um on slide 30 we're + + + align:start position:0% +given temperature um on slide 30 we're +doing just the opposite now it it's not + + align:start position:0% +doing just the opposite now it it's not + + + align:start position:0% +doing just the opposite now it it's not +so easy to do from um a physical point + + align:start position:0% +so easy to do from um a physical point + + + align:start position:0% +so easy to do from um a physical point +of view but you can imagine growing at + + align:start position:0% +of view but you can imagine growing at + + + align:start position:0% +of view but you can imagine growing at +higher than one pressure um let's say + + align:start position:0% +higher than one pressure um let's say + + + align:start position:0% +higher than one pressure um let's say +you know the pressure tells you what it + + align:start position:0% +you know the pressure tells you what it + + + align:start position:0% +you know the pressure tells you what it +tells you the number of atoms or + + align:start position:0% +tells you the number of atoms or + + + align:start position:0% +tells you the number of atoms or +molecules you know species hitting the + + align:start position:0% +molecules you know species hitting the + + + align:start position:0% +molecules you know species hitting the +the surface per unit time right so if I + + align:start position:0% +the surface per unit time right so if I + + + align:start position:0% +the surface per unit time right so if I +double that pressure I can double the + + align:start position:0% +double that pressure I can double the + + + align:start position:0% +double that pressure I can double the +amount there uh hitting that surface I + + align:start position:0% +amount there uh hitting that surface I + + + align:start position:0% +amount there uh hitting that surface I +can double the flux to the surface so + + align:start position:0% +can double the flux to the surface so + + + align:start position:0% +can double the flux to the surface so +you expect the growth rate to go up uh + + align:start position:0% +you expect the growth rate to go up uh + + + align:start position:0% +you expect the growth rate to go up uh +it's just you know not in your intuition + + align:start position:0% +it's just you know not in your intuition + + + align:start position:0% +it's just you know not in your intuition +of how I could do that here you have a + + align:start position:0% +of how I could do that here you have a + + + align:start position:0% +of how I could do that here you have a +tube uh that's made of quartz I have it + + align:start position:0% +tube uh that's made of quartz I have it + + + align:start position:0% +tube uh that's made of quartz I have it +open to on both ends to the ambient and + + align:start position:0% +open to on both ends to the ambient and + + + align:start position:0% +open to on both ends to the ambient and +I'm flowing some gas SW how you going to + + align:start position:0% +I'm flowing some gas SW how you going to + + + align:start position:0% +I'm flowing some gas SW how you going to +get a higher pressure we're all at + + align:start position:0% +get a higher pressure we're all at + + + align:start position:0% +get a higher pressure we're all at +atmospheric pressure doesn't work but + + align:start position:0% +atmospheric pressure doesn't work but + + + align:start position:0% +atmospheric pressure doesn't work but +you can do it you can build a system + + align:start position:0% +you can do it you can build a system + + + align:start position:0% +you can do it you can build a system +where outside that quartz tube there's a + + align:start position:0% +where outside that quartz tube there's a + + + align:start position:0% +where outside that quartz tube there's a +big envelope made of stainless steel + + align:start position:0% +big envelope made of stainless steel + + + align:start position:0% +big envelope made of stainless steel +like a divers tank right if you take + + align:start position:0% +like a divers tank right if you take + + + align:start position:0% +like a divers tank right if you take +they have training tanks for deep sea + + align:start position:0% +they have training tanks for deep sea + + + align:start position:0% +they have training tanks for deep sea +divers they put these guys in these + + align:start position:0% +divers they put these guys in these + + + align:start position:0% +divers they put these guys in these +tanks they seal it up like a submarine + + align:start position:0% +tanks they seal it up like a submarine + + + align:start position:0% +tanks they seal it up like a submarine +and they can stuff more and more gas in + + align:start position:0% +and they can stuff more and more gas in + + + align:start position:0% +and they can stuff more and more gas in +there and you can increase the pressure + + align:start position:0% +there and you can increase the pressure + + + align:start position:0% +there and you can increase the pressure +on the diver um so that's EX exactly + + align:start position:0% +on the diver um so that's EX exactly + + + align:start position:0% +on the diver um so that's EX exactly +what people do with high press oxidation + + align:start position:0% +what people do with high press oxidation + + + align:start position:0% +what people do with high press oxidation +it's a very special type of equipment + + align:start position:0% +it's a very special type of equipment + + + align:start position:0% +it's a very special type of equipment +it's not something you're going to find + + align:start position:0% +it's not something you're going to find + + + align:start position:0% +it's not something you're going to find +in the standard Fab they are available + + align:start position:0% +in the standard Fab they are available + + + align:start position:0% +in the standard Fab they are available +though they've been commercially made + + align:start position:0% +though they've been commercially made + + + align:start position:0% +though they've been commercially made +and people call it hyox a high pressure + + align:start position:0% +and people call it hyox a high pressure + + + align:start position:0% +and people call it hyox a high pressure +oxidation system so here's an example of + + align:start position:0% +oxidation system so here's an example of + + + align:start position:0% +oxidation system so here's an example of +how the kinetics would would go up and + + align:start position:0% +how the kinetics would would go up and + + + align:start position:0% +how the kinetics would would go up and +this I took from uh mayor and LA's book + + align:start position:0% +this I took from uh mayor and LA's book + + + align:start position:0% +this I took from uh mayor and LA's book +1990 what they're showing here is on a + + align:start position:0% +1990 what they're showing here is on a + + + align:start position:0% +1990 what they're showing here is on a +on a log plot here a semi log so it's + + align:start position:0% +on a log plot here a semi log so it's + + + align:start position:0% +on a log plot here a semi log so it's +log on the Y linear on uh on the X oxide + + align:start position:0% +log on the Y linear on uh on the X oxide + + + align:start position:0% +log on the Y linear on uh on the X oxide +thickness versus time + + align:start position:0% +thickness versus time + + + align:start position:0% +thickness versus time +and this is 10 in Steam and uh they're + + align:start position:0% +and this is 10 in Steam and uh they're + + + align:start position:0% +and this is 10 in Steam and uh they're +looking at versus temperature I'm sorry + + align:start position:0% +looking at versus temperature I'm sorry + + + align:start position:0% +looking at versus temperature I'm sorry +looking at a couple different curves + + align:start position:0% +looking at a couple different curves + + + align:start position:0% +looking at a couple different curves +here at different pressure so an + + align:start position:0% +here at different pressure so an + + + align:start position:0% +here at different pressure so an +atmospheric pressure it looks like this + + align:start position:0% +atmospheric pressure it looks like this + + + align:start position:0% +atmospheric pressure it looks like this +at five pressure uh five atmospheres or + + align:start position:0% +at five pressure uh five atmospheres or + + + align:start position:0% +at five pressure uh five atmospheres or +10 atmospheres uh it looks like this + + align:start position:0% +10 atmospheres uh it looks like this + + + align:start position:0% +10 atmospheres uh it looks like this +here we are 20 atmospheres look how much + + align:start position:0% +here we are 20 atmospheres look how much + + + align:start position:0% +here we are 20 atmospheres look how much +faster we can grow um so um this can be + + align:start position:0% +faster we can grow um so um this can be + + + align:start position:0% +faster we can grow um so um this can be +used to increase the oxidation grate at + + align:start position:0% +used to increase the oxidation grate at + + + align:start position:0% +used to increase the oxidation grate at +low temperatures if you need to grow a + + align:start position:0% +low temperatures if you need to grow a + + + align:start position:0% +low temperatures if you need to grow a +thick oxide thermally you need to have + + align:start position:0% +thick oxide thermally you need to have + + + align:start position:0% +thick oxide thermally you need to have +the properties of a thermal oxide which + + align:start position:0% +the properties of a thermal oxide which + + + align:start position:0% +the properties of a thermal oxide which +are quite unique its density is well + + align:start position:0% +are quite unique its density is well + + + align:start position:0% +are quite unique its density is well +defined um it has much better electrical + + align:start position:0% +defined um it has much better electrical + + + align:start position:0% +defined um it has much better electrical +properties than you would get by + + align:start position:0% +properties than you would get by + + + align:start position:0% +properties than you would get by +depositing an oxide it actually consumes + + align:start position:0% +depositing an oxide it actually consumes + + + align:start position:0% +depositing an oxide it actually consumes +silicon which is not true of a deposited + + align:start position:0% +silicon which is not true of a deposited + + + align:start position:0% +silicon which is not true of a deposited +oxide then you have to go to a hypox + + align:start position:0% +oxide then you have to go to a hypox + + + align:start position:0% +oxide then you have to go to a hypox +process or let's say you have some + + align:start position:0% +process or let's say you have some + + + align:start position:0% +process or let's say you have some +structure on the surf on the surface + + align:start position:0% +structure on the surf on the surface + + + align:start position:0% +structure on the surf on the surface +like silic and geranium or some material + + align:start position:0% +like silic and geranium or some material + + + align:start position:0% +like silic and geranium or some material +that can't go to a high temperature + + align:start position:0% +that can't go to a high temperature + + + align:start position:0% +that can't go to a high temperature +because it'll it'll it'll cause the + + align:start position:0% +because it'll it'll it'll cause the + + + align:start position:0% +because it'll it'll it'll cause the +material to diffuse or to relax or you + + align:start position:0% +material to diffuse or to relax or you + + + align:start position:0% +material to diffuse or to relax or you +have you're trying to limit the amount + + align:start position:0% +have you're trying to limit the amount + + + align:start position:0% +have you're trying to limit the amount +of diffusion in the substrate well and + + align:start position:0% +of diffusion in the substrate well and + + + align:start position:0% +of diffusion in the substrate well and +you need to grow a thick oxide you can + + align:start position:0% +you need to grow a thick oxide you can + + + align:start position:0% +you need to grow a thick oxide you can +do it in a high machine uh at 800 where + + align:start position:0% +do it in a high machine uh at 800 where + + + align:start position:0% +do it in a high machine uh at 800 where +you never would be able to do you know + + align:start position:0% +you never would be able to do you know + + + align:start position:0% +you never would be able to do you know +grow a half a micron at 800 but you can + + align:start position:0% +grow a half a micron at 800 but you can + + + align:start position:0% +grow a half a micron at 800 but you can +do it in hyox at 20 atmospher so for + + align:start position:0% +do it in hyox at 20 atmospher so for + + + align:start position:0% +do it in hyox at 20 atmospher so for +materials that are and processes that + + align:start position:0% +materials that are and processes that + + + align:start position:0% +materials that are and processes that +are getting limited by temperature and + + align:start position:0% +are getting limited by temperature and + + + align:start position:0% +are getting limited by temperature and +they have to go lower and lower in + + align:start position:0% +they have to go lower and lower in + + + align:start position:0% +they have to go lower and lower in +temperature hpox is away of uh of + + align:start position:0% +temperature hpox is away of uh of + + + align:start position:0% +temperature hpox is away of uh of +increase in the oxidation + + align:start position:0% + + + + align:start position:0% + +rate so in fact here's some data uh + + align:start position:0% +rate so in fact here's some data uh + + + align:start position:0% +rate so in fact here's some data uh +shown on slide + + align:start position:0% +shown on slide + + + align:start position:0% +shown on slide +31 um on hyox I took from Simon z uh in + + align:start position:0% +31 um on hyox I took from Simon z uh in + + + align:start position:0% +31 um on hyox I took from Simon z uh in +Z's book and what it shows is the + + align:start position:0% +Z's book and what it shows is the + + + align:start position:0% +Z's book and what it shows is the +measurements of the on the y- axis the + + align:start position:0% +measurements of the on the y- axis the + + + align:start position:0% +measurements of the on the y- axis the +parabolic rate constant so this is the B + + align:start position:0% +parabolic rate constant so this is the B + + + align:start position:0% +parabolic rate constant so this is the B +parameter as a function of one th overt + + align:start position:0% +parameter as a function of one th overt + + + align:start position:0% +parameter as a function of one th overt +so it's a semilog kind of arous + + align:start position:0% +so it's a semilog kind of arous + + + align:start position:0% +so it's a semilog kind of arous +plot um in Steam and this applies to a + + align:start position:0% +plot um in Steam and this applies to a + + + align:start position:0% +plot um in Steam and this applies to a +couple different it's been measured for + + align:start position:0% +couple different it's been measured for + + + align:start position:0% +couple different it's been measured for +a couple different orientations uh of + + align:start position:0% +a couple different orientations uh of + + + align:start position:0% +a couple different orientations uh of +silicon and what you see here is this + + align:start position:0% +silicon and what you see here is this + + + align:start position:0% +silicon and what you see here is this +this solid line uh which has an act two + + align:start position:0% +this solid line uh which has an act two + + + align:start position:0% +this solid line uh which has an act two +different activation energies there seem + + align:start position:0% +different activation energies there seem + + + align:start position:0% +different activation energies there seem +to be a break point here somewhere + + align:start position:0% +to be a break point here somewhere + + + align:start position:0% +to be a break point here somewhere +around 950 degrees but um AC activation + + align:start position:0% +around 950 degrees but um AC activation + + + align:start position:0% +around 950 degrees but um AC activation +energy close to one electron volt this + + align:start position:0% +energy close to one electron volt this + + + align:start position:0% +energy close to one electron volt this +is the this is the B parameter here at + + align:start position:0% +is the this is the B parameter here at + + + align:start position:0% +is the this is the B parameter here at +five 10 15 and 20 + + align:start position:0% +five 10 15 and 20 + + + align:start position:0% +five 10 15 and 20 +atmospheres um this is what the B + + align:start position:0% +atmospheres um this is what the B + + + align:start position:0% +atmospheres um this is what the B +parameter goes up by and in fact I mark + + align:start position:0% +parameter goes up by and in fact I mark + + + align:start position:0% +parameter goes up by and in fact I mark +this blue line which is at 800° and in + + align:start position:0% +this blue line which is at 800° and in + + + align:start position:0% +this blue line which is at 800° and in +fact I'm reading off the chart here uh + + align:start position:0% +fact I'm reading off the chart here uh + + + align:start position:0% +fact I'm reading off the chart here uh +the B parameter is almost exactly a + + align:start position:0% +the B parameter is almost exactly a + + + align:start position:0% +the B parameter is almost exactly a +factor of 20 faster uh at 20 atmospheres + + align:start position:0% +factor of 20 faster uh at 20 atmospheres + + + align:start position:0% +factor of 20 faster uh at 20 atmospheres +than it is um at one atmosphere so we + + align:start position:0% +than it is um at one atmosphere so we + + + align:start position:0% +than it is um at one atmosphere so we +can go up um to uh 20 times the + + align:start position:0% +can go up um to uh 20 times the + + + align:start position:0% +can go up um to uh 20 times the +oxidation rate at 20 atmospheres at 800° + + align:start position:0% +oxidation rate at 20 atmospheres at 800° + + + align:start position:0% +oxidation rate at 20 atmospheres at 800° +so it does scale reasonably well this + + align:start position:0% +so it does scale reasonably well this + + + align:start position:0% +so it does scale reasonably well this +parameter does uh with uh pressure at + + align:start position:0% +parameter does uh with uh pressure at + + + align:start position:0% +parameter does uh with uh pressure at +higher + + align:start position:0% + + + + align:start position:0% + +pressures um on slide 32 I'm actually + + align:start position:0% +pressures um on slide 32 I'm actually + + + align:start position:0% +pressures um on slide 32 I'm actually +showing you remember I said um you can + + align:start position:0% +showing you remember I said um you can + + + align:start position:0% +showing you remember I said um you can +build this complex diver tank looking + + align:start position:0% +build this complex diver tank looking + + + align:start position:0% +build this complex diver tank looking +thing with a great big steel uh vacuum + + align:start position:0% +thing with a great big steel uh vacuum + + + align:start position:0% +thing with a great big steel uh vacuum +system that can hold the pressure and + + align:start position:0% +system that can hold the pressure and + + + align:start position:0% +system that can hold the pressure and +pressurization system um I've taken this + + align:start position:0% +pressurization system um I've taken this + + + align:start position:0% +pressurization system um I've taken this +from Simon Z's book he actually talks + + align:start position:0% +from Simon Z's book he actually talks + + + align:start position:0% +from Simon Z's book he actually talks +about how you would do um a hpox run if + + align:start position:0% +about how you would do um a hpox run if + + + align:start position:0% +about how you would do um a hpox run if +you had such a thing just so you can + + align:start position:0% +you had such a thing just so you can + + + align:start position:0% +you had such a thing just so you can +think about it what what happens is the + + align:start position:0% +think about it what what happens is the + + + align:start position:0% +think about it what what happens is the +Wafers um get loaded here at atmospheric + + align:start position:0% +Wafers um get loaded here at atmospheric + + + align:start position:0% +Wafers um get loaded here at atmospheric +pressure down here this solid uh bar it + + align:start position:0% +pressure down here this solid uh bar it + + + align:start position:0% +pressure down here this solid uh bar it +means you're at atmospheric pressure + + align:start position:0% +means you're at atmospheric pressure + + + align:start position:0% +means you're at atmospheric pressure +obviously you can't pump up the diver + + align:start position:0% +obviously you can't pump up the diver + + + align:start position:0% +obviously you can't pump up the diver +tank until uh the the hatch is closed so + + align:start position:0% +tank until uh the the hatch is closed so + + + align:start position:0% +tank until uh the the hatch is closed so +you load them in atmospheric pressure uh + + align:start position:0% +you load them in atmospheric pressure uh + + + align:start position:0% +you load them in atmospheric pressure uh +and you uh have a ceiling step and here + + align:start position:0% +and you uh have a ceiling step and here + + + align:start position:0% +and you uh have a ceiling step and here +you're starting to increase the pressure + + align:start position:0% +you're starting to increase the pressure + + + align:start position:0% +you're starting to increase the pressure +um again using O2 um you do some purging + + align:start position:0% +um again using O2 um you do some purging + + + align:start position:0% +um again using O2 um you do some purging +and then it's some point what you do is + + align:start position:0% +and then it's some point what you do is + + + align:start position:0% +and then it's some point what you do is +you bring the shell uh this outside + + align:start position:0% +you bring the shell uh this outside + + + align:start position:0% +you bring the shell uh this outside +steel shell and the tube up together in + + align:start position:0% +steel shell and the tube up together in + + + align:start position:0% +steel shell and the tube up together in +pressure and you go up to say 10 + + align:start position:0% +pressure and you go up to say 10 + + + align:start position:0% +pressure and you go up to say 10 +atmospheres um you do your um so you're + + align:start position:0% +atmospheres um you do your um so you're + + + align:start position:0% +atmospheres um you do your um so you're +pressurizing uh in moisture and then you + + align:start position:0% +pressurizing uh in moisture and then you + + + align:start position:0% +pressurizing uh in moisture and then you +you do your oxidation then you + + align:start position:0% +you do your oxidation then you + + + align:start position:0% +you do your oxidation then you +depressurize um and bring it down to + + align:start position:0% +depressurize um and bring it down to + + + align:start position:0% +depressurize um and bring it down to +atmospheric pressure and unload so it's + + align:start position:0% +atmospheric pressure and unload so it's + + + align:start position:0% +atmospheric pressure and unload so it's +perfectly possible to do this obviously + + align:start position:0% +perfectly possible to do this obviously + + + align:start position:0% +perfectly possible to do this obviously +if you try to do it with a quartz tube + + align:start position:0% +if you try to do it with a quartz tube + + + align:start position:0% +if you try to do it with a quartz tube +and put end caps on it pressurize it of + + align:start position:0% +and put end caps on it pressurize it of + + + align:start position:0% +and put end caps on it pressurize it of +course the quartz would explode all over + + align:start position:0% +course the quartz would explode all over + + + align:start position:0% +course the quartz would explode all over +so because it's not a strong material + + align:start position:0% +so because it's not a strong material + + + align:start position:0% +so because it's not a strong material +but if you um you know you have the + + align:start position:0% +but if you um you know you have the + + + align:start position:0% +but if you um you know you have the +stainless steel shroud all around it + + align:start position:0% +stainless steel shroud all around it + + + align:start position:0% +stainless steel shroud all around it +then the differential pressure across + + align:start position:0% +then the differential pressure across + + + align:start position:0% +then the differential pressure across +the quartz is is very close to zero or + + align:start position:0% +the quartz is is very close to zero or + + + align:start position:0% +the quartz is is very close to zero or +it can be uh just maybe one atmosphere + + align:start position:0% +it can be uh just maybe one atmosphere + + + align:start position:0% +it can be uh just maybe one atmosphere +we know it can withstand one atmosphere + + align:start position:0% +we know it can withstand one atmosphere + + + align:start position:0% +we know it can withstand one atmosphere +but that way you you keep the quartz + + align:start position:0% +but that way you you keep the quartz + + + align:start position:0% +but that way you you keep the quartz +from uh exploding all over the place so + + align:start position:0% +from uh exploding all over the place so + + + align:start position:0% +from uh exploding all over the place so +it's a special piece of + + align:start position:0% + + + + align:start position:0% + +equipment okay so then let's go on to + + align:start position:0% +equipment okay so then let's go on to + + + align:start position:0% +equipment okay so then let's go on to +slide 33 so high poox you can do low + + align:start position:0% +slide 33 so high poox you can do low + + + align:start position:0% +slide 33 so high poox you can do low +pressures you can do high pressures if + + align:start position:0% +pressures you can do high pressures if + + + align:start position:0% +pressures you can do high pressures if +you have the right equipment um it turns + + align:start position:0% +you have the right equipment um it turns + + + align:start position:0% +you have the right equipment um it turns +out simple oxidation also isn't always + + align:start position:0% +out simple oxidation also isn't always + + + align:start position:0% +out simple oxidation also isn't always +done just with oxygen or water vapor um + + align:start position:0% +done just with oxygen or water vapor um + + + align:start position:0% +done just with oxygen or water vapor um +small concentrations of certain other + + align:start position:0% +small concentrations of certain other + + + align:start position:0% +small concentrations of certain other +species are often added for example HCL + + align:start position:0% +species are often added for example HCL + + + align:start position:0% +species are often added for example HCL +is sometimes added to the O2 um because + + align:start position:0% +is sometimes added to the O2 um because + + + align:start position:0% +is sometimes added to the O2 um because +it turns out people are found by adding + + align:start position:0% +it turns out people are found by adding + + + align:start position:0% +it turns out people are found by adding +that they can reduce oxide defect + + align:start position:0% +that they can reduce oxide defect + + + align:start position:0% +that they can reduce oxide defect +densities uh or they can reduce + + align:start position:0% +densities uh or they can reduce + + + align:start position:0% +densities uh or they can reduce +contamination levels HCL we know in the + + align:start position:0% +contamination levels HCL we know in the + + + align:start position:0% +contamination levels HCL we know in the +liquid form HCL is very good at um uh + + align:start position:0% +liquid form HCL is very good at um uh + + + align:start position:0% +liquid form HCL is very good at um uh +etching off metals from the surface so + + align:start position:0% +etching off metals from the surface so + + + align:start position:0% +etching off metals from the surface so +perhaps it has a similar role uh when + + align:start position:0% +perhaps it has a similar role uh when + + + align:start position:0% +perhaps it has a similar role uh when +it's in the Vapor face so sometimes + + align:start position:0% +it's in the Vapor face so sometimes + + + align:start position:0% +it's in the Vapor face so sometimes +people add a small am of HCL to the + + align:start position:0% +people add a small am of HCL to the + + + align:start position:0% +people add a small am of HCL to the +furnace um it can produce chlorine which + + align:start position:0% +furnace um it can produce chlorine which + + + align:start position:0% +furnace um it can produce chlorine which +can react with maybe Trace + + align:start position:0% +can react with maybe Trace + + + align:start position:0% +can react with maybe Trace +Metals um by this this kind of process + + align:start position:0% +Metals um by this this kind of process + + + align:start position:0% +Metals um by this this kind of process +that's shown here so it's not unusual to + + align:start position:0% +that's shown here so it's not unusual to + + + align:start position:0% +that's shown here so it's not unusual to +see in manufacturing processes oxidation + + align:start position:0% +see in manufacturing processes oxidation + + + align:start position:0% +see in manufacturing processes oxidation +in not just O2 but HCL O2 plus + + align:start position:0% +in not just O2 but HCL O2 plus + + + align:start position:0% +in not just O2 but HCL O2 plus +HCL um so these uh these bullets here in + + align:start position:0% +HCL um so these uh these bullets here in + + + align:start position:0% +HCL um so these uh these bullets here in +the middle of the slide there's just + + align:start position:0% +the middle of the slide there's just + + + align:start position:0% +the middle of the slide there's just +some generic kind of observations that + + align:start position:0% +some generic kind of observations that + + + align:start position:0% +some generic kind of observations that +have been made on these different + + align:start position:0% +have been made on these different + + + align:start position:0% +have been made on these different +ambients uh well we know we just studied + + align:start position:0% +ambients uh well we know we just studied + + + align:start position:0% +ambients uh well we know we just studied +in Deal Grove we know in detail that you + + align:start position:0% +in Deal Grove we know in detail that you + + + align:start position:0% +in Deal Grove we know in detail that you +can get 20 to 50 times faster um than + + align:start position:0% +can get 20 to 50 times faster um than + + + align:start position:0% +can get 20 to 50 times faster um than +dry O2 just by putting in in wet O2 in + + align:start position:0% +dry O2 just by putting in in wet O2 in + + + align:start position:0% +dry O2 just by putting in in wet O2 in +in Steam so we know that um 3% chlorine + + align:start position:0% +in Steam so we know that um 3% chlorine + + + align:start position:0% +in Steam so we know that um 3% chlorine +in the ambient can increase the growth + + align:start position:0% +in the ambient can increase the growth + + + align:start position:0% +in the ambient can increase the growth +rate by 20 to 30% so also HCL is a way + + align:start position:0% +rate by 20 to 30% so also HCL is a way + + + align:start position:0% +rate by 20 to 30% so also HCL is a way +of at a at a low temperature is boosting + + align:start position:0% +of at a at a low temperature is boosting + + + align:start position:0% +of at a at a low temperature is boosting +the growth rate the name of the game + + align:start position:0% +the growth rate the name of the game + + + align:start position:0% +the growth rate the name of the game +these days is keep the dopin from moving + + align:start position:0% +these days is keep the dopin from moving + + + align:start position:0% +these days is keep the dopin from moving +but keep the growth rate high enough to + + align:start position:0% +but keep the growth rate high enough to + + + align:start position:0% +but keep the growth rate high enough to +be to be give you a reasonable thickness + + align:start position:0% +be to be give you a reasonable thickness + + + align:start position:0% +be to be give you a reasonable thickness +so you can add a little chlorine to + + align:start position:0% +so you can add a little chlorine to + + + align:start position:0% +so you can add a little chlorine to +speed up the growth rate + + align:start position:0% +speed up the growth rate + + + align:start position:0% +speed up the growth rate +you can also add nf3 another U commonly + + align:start position:0% +you can also add nf3 another U commonly + + + align:start position:0% +you can also add nf3 another U commonly +used species a small amount of that will + + align:start position:0% +used species a small amount of that will + + + align:start position:0% +used species a small amount of that will +increase the growth rate by two to three + + align:start position:0% +increase the growth rate by two to three + + + align:start position:0% +increase the growth rate by two to three +times um again this is adding in a lot + + align:start position:0% +times um again this is adding in a lot + + + align:start position:0% +times um again this is adding in a lot +of new chemistry and there's no way in + + align:start position:0% +of new chemistry and there's no way in + + + align:start position:0% +of new chemistry and there's no way in +an abono in a first principal sense to + + align:start position:0% +an abono in a first principal sense to + + + align:start position:0% +an abono in a first principal sense to +really calculate what those rates are so + + align:start position:0% +really calculate what those rates are so + + + align:start position:0% +really calculate what those rates are so +in in simulators like Supreme 4 if you + + align:start position:0% +in in simulators like Supreme 4 if you + + + align:start position:0% +in in simulators like Supreme 4 if you +go sit down and tell it oh I want to + + align:start position:0% +go sit down and tell it oh I want to + + + align:start position:0% +go sit down and tell it oh I want to +grow an oxide in chlorine and oxygen it + + align:start position:0% +grow an oxide in chlorine and oxygen it + + + align:start position:0% +grow an oxide in chlorine and oxygen it +doesn't simulate the chemical reaction + + align:start position:0% +doesn't simulate the chemical reaction + + + align:start position:0% +doesn't simulate the chemical reaction +and all the kinetics and come on spit + + align:start position:0% +and all the kinetics and come on spit + + + align:start position:0% +and all the kinetics and come on spit +out a number it has a lookup table of B + + align:start position:0% +out a number it has a lookup table of B + + + align:start position:0% +out a number it has a lookup table of B +and Bay values that have been measured + + align:start position:0% +and Bay values that have been measured + + + align:start position:0% +and Bay values that have been measured +in the literature for commonly used + + align:start position:0% +in the literature for commonly used + + + align:start position:0% +in the literature for commonly used +ambients like chlorine and maybe nf3 and + + align:start position:0% +ambients like chlorine and maybe nf3 and + + + align:start position:0% +ambients like chlorine and maybe nf3 and +a few others so it looks up in the table + + align:start position:0% +a few others so it looks up in the table + + + align:start position:0% +a few others so it looks up in the table +uh what B over A and B should be um uh + + align:start position:0% +uh what B over A and B should be um uh + + + align:start position:0% +uh what B over A and B should be um uh +as a function of the pressure here this + + align:start position:0% +as a function of the pressure here this + + + align:start position:0% +as a function of the pressure here this +pressure Delta or Kai these are some + + align:start position:0% +pressure Delta or Kai these are some + + + align:start position:0% +pressure Delta or Kai these are some +functions of the concentration of this + + align:start position:0% +functions of the concentration of this + + + align:start position:0% +functions of the concentration of this +additional uh species that's in the + + align:start position:0% +additional uh species that's in the + + + align:start position:0% +additional uh species that's in the +furnace could it be HCL or whatever and + + align:start position:0% +furnace could it be HCL or whatever and + + + align:start position:0% +furnace could it be HCL or whatever and +they've been determined very empirically + + align:start position:0% +they've been determined very empirically + + + align:start position:0% +they've been determined very empirically +so don't expect first principles models + + align:start position:0% +so don't expect first principles models + + + align:start position:0% +so don't expect first principles models +but maybe some mathematical models would + + align:start position:0% +but maybe some mathematical models would + + + align:start position:0% +but maybe some mathematical models would +be in Supreme for different ambients but + + align:start position:0% +be in Supreme for different ambients but + + + align:start position:0% +be in Supreme for different ambients but +again they've all been calibrated + + align:start position:0% +again they've all been calibrated + + + align:start position:0% +again they've all been calibrated +somebody's experiment so you know they + + align:start position:0% +somebody's experiment so you know they + + + align:start position:0% +somebody's experiment so you know they +may not exactly agree with your + + align:start position:0% +may not exactly agree with your + + + align:start position:0% +may not exactly agree with your +experiment you might have to calibrate + + align:start position:0% +experiment you might have to calibrate + + + align:start position:0% +experiment you might have to calibrate +it + + align:start position:0% + + + + align:start position:0% + +yourself uh here's an interesting + + align:start position:0% +yourself uh here's an interesting + + + align:start position:0% +yourself uh here's an interesting +example on slide uh + + align:start position:0% +example on slide uh + + + align:start position:0% +example on slide uh +34 these are some kinetics in um HCL has + + align:start position:0% +34 these are some kinetics in um HCL has + + + align:start position:0% +34 these are some kinetics in um HCL has +been used for quite a while it's it's + + align:start position:0% +been used for quite a while it's it's + + + align:start position:0% +been used for quite a while it's it's +even my old fashioned now something + + align:start position:0% +even my old fashioned now something + + + align:start position:0% +even my old fashioned now something +that's a little bit newer is people + + align:start position:0% +that's a little bit newer is people + + + align:start position:0% +that's a little bit newer is people +oxidizing an Ambience like n o n2o and + + align:start position:0% +oxidizing an Ambience like n o n2o and + + + align:start position:0% +oxidizing an Ambience like n o n2o and +even implanting nitrogen remember we + + align:start position:0% +even implanting nitrogen remember we + + + align:start position:0% +even implanting nitrogen remember we +talked about oxy nitrides um are the + + align:start position:0% +talked about oxy nitrides um are the + + + align:start position:0% +talked about oxy nitrides um are the +first form of high K uh oxy nitride + + align:start position:0% +first form of high K uh oxy nitride + + + align:start position:0% +first form of high K uh oxy nitride +which is a mixture of silicon oxygen and + + align:start position:0% +which is a mixture of silicon oxygen and + + + align:start position:0% +which is a mixture of silicon oxygen and +nitrogen has a higher dialectric + + align:start position:0% +nitrogen has a higher dialectric + + + align:start position:0% +nitrogen has a higher dialectric +constant you can make it a little bit + + align:start position:0% +constant you can make it a little bit + + + align:start position:0% +constant you can make it a little bit +thicker and so you get less gate leakage + + align:start position:0% +thicker and so you get less gate leakage + + + align:start position:0% +thicker and so you get less gate leakage +so gate oxides of oxy nitride were very + + align:start position:0% +so gate oxides of oxy nitride were very + + + align:start position:0% +so gate oxides of oxy nitride were very +popular for people are popular for + + align:start position:0% +popular for people are popular for + + + align:start position:0% +popular for people are popular for +people to study but um here's an example + + align:start position:0% +people to study but um here's an example + + + align:start position:0% +people to study but um here's an example +of trying to fabricate an oxy nitride + + align:start position:0% +of trying to fabricate an oxy nitride + + + align:start position:0% +of trying to fabricate an oxy nitride +where the kinetics are really crazy + + align:start position:0% +where the kinetics are really crazy + + + align:start position:0% +where the kinetics are really crazy +they're not at all linear parabolic and + + align:start position:0% +they're not at all linear parabolic and + + + align:start position:0% +they're not at all linear parabolic and +uh in fact this is a plot here on the y + + align:start position:0% +uh in fact this is a plot here on the y + + + align:start position:0% +uh in fact this is a plot here on the y +axis is oxide thickness uh or oxy + + align:start position:0% +axis is oxide thickness uh or oxy + + + align:start position:0% +axis is oxide thickness uh or oxy +nitrite thickness if you want as a + + align:start position:0% +nitrite thickness if you want as a + + + align:start position:0% +nitrite thickness if you want as a +function of the nitrogen + + align:start position:0% +function of the nitrogen + + + align:start position:0% +function of the nitrogen +dose um so here the the substrate was + + align:start position:0% +dose um so here the the substrate was + + + align:start position:0% +dose um so here the the substrate was +implanted first with nitrogen and we'll + + align:start position:0% +implanted first with nitrogen and we'll + + + align:start position:0% +implanted first with nitrogen and we'll +talk about ion implantation to a certain + + align:start position:0% +talk about ion implantation to a certain + + + align:start position:0% +talk about ion implantation to a certain +number of atoms per square + + align:start position:0% +number of atoms per square + + + align:start position:0% +number of atoms per square +centimeter and they're plotting the + + align:start position:0% +centimeter and they're plotting the + + + align:start position:0% +centimeter and they're plotting the +oxide thickness here uh at different + + align:start position:0% +oxide thickness here uh at different + + + align:start position:0% +oxide thickness here uh at different +times so say for 25 minutes as a + + align:start position:0% +times so say for 25 minutes as a + + + align:start position:0% +times so say for 25 minutes as a +function of of dose uh um and you can + + align:start position:0% +function of of dose uh um and you can + + + align:start position:0% +function of of dose uh um and you can +see depending on how the dose how much + + align:start position:0% +see depending on how the dose how much + + + align:start position:0% +see depending on how the dose how much +of nitrogen you implanted the thickness + + align:start position:0% +of nitrogen you implanted the thickness + + + align:start position:0% +of nitrogen you implanted the thickness +actually um can go down so the the + + align:start position:0% +actually um can go down so the the + + + align:start position:0% +actually um can go down so the the +oxidation rate can depend on exactly + + align:start position:0% +oxidation rate can depend on exactly + + + align:start position:0% +oxidation rate can depend on exactly +what is at that surface was it silicon + + align:start position:0% +what is at that surface was it silicon + + + align:start position:0% +what is at that surface was it silicon +Pure or was it silicon that had been on + + align:start position:0% +Pure or was it silicon that had been on + + + align:start position:0% +Pure or was it silicon that had been on +implanted with something um so uh this + + align:start position:0% +implanted with something um so uh this + + + align:start position:0% +implanted with something um so uh this +needs a very a qualitatively very + + align:start position:0% +needs a very a qualitatively very + + + align:start position:0% +needs a very a qualitatively very +different model from deal Grove because + + align:start position:0% +different model from deal Grove because + + + align:start position:0% +different model from deal Grove because +you need to specify something that the + + align:start position:0% +you need to specify something that the + + + align:start position:0% +you need to specify something that the +deal Grove doesn't even treat deal Grove + + align:start position:0% +deal Grove doesn't even treat deal Grove + + + align:start position:0% +deal Grove doesn't even treat deal Grove +assumed you had a perfectly pure silicon + + align:start position:0% +assumed you had a perfectly pure silicon + + + align:start position:0% +assumed you had a perfectly pure silicon +wafer that you were oxidizing with just + + align:start position:0% +wafer that you were oxidizing with just + + + align:start position:0% +wafer that you were oxidizing with just +silicon atoms in it once you start + + align:start position:0% +silicon atoms in it once you start + + + align:start position:0% +silicon atoms in it once you start +implanting nitrogen or some other + + align:start position:0% +implanting nitrogen or some other + + + align:start position:0% +implanting nitrogen or some other +species all bets are off you're not + + align:start position:0% +species all bets are off you're not + + + align:start position:0% +species all bets are off you're not +going to widely find uh simulators that + + align:start position:0% +going to widely find uh simulators that + + + align:start position:0% +going to widely find uh simulators that +can support this type of model if you + + align:start position:0% +can support this type of model if you + + + align:start position:0% +can support this type of model if you +want to do this you're going to have to + + align:start position:0% +want to do this you're going to have to + + + align:start position:0% +want to do this you're going to have to +model it yourself um by taking data from + + align:start position:0% +model it yourself um by taking data from + + + align:start position:0% +model it yourself um by taking data from +the literature and fitting it um or or + + align:start position:0% +the literature and fitting it um or or + + + align:start position:0% +the literature and fitting it um or or +maybe doing your own + + align:start position:0% + + + + align:start position:0% + +experiments um so let's look at um slide + + align:start position:0% +experiments um so let's look at um slide + + + align:start position:0% +experiments um so let's look at um slide +35 there's another parameter we need to + + align:start position:0% +35 there's another parameter we need to + + + align:start position:0% +35 there's another parameter we need to +vary or we can you can imagine varying + + align:start position:0% +vary or we can you can imagine varying + + + align:start position:0% +vary or we can you can imagine varying +and this is a relatively simple one and + + align:start position:0% +and this is a relatively simple one and + + + align:start position:0% +and this is a relatively simple one and +that's the orientation of the crystal + + align:start position:0% +that's the orientation of the crystal + + + align:start position:0% +that's the orientation of the crystal +the face of the crystal that you're + + align:start position:0% +the face of the crystal that you're + + + align:start position:0% +the face of the crystal that you're +oxidizing um we know that the B + + align:start position:0% +oxidizing um we know that the B + + + align:start position:0% +oxidizing um we know that the B +parameter which depends on the diffusion + + align:start position:0% +parameter which depends on the diffusion + + + align:start position:0% +parameter which depends on the diffusion +through the oxide is independent of + + align:start position:0% +through the oxide is independent of + + + align:start position:0% +through the oxide is independent of +orientation B over a which is the the + + align:start position:0% +orientation B over a which is the the + + + align:start position:0% +orientation B over a which is the the +the the reaction rate at the at the + + align:start position:0% +the the reaction rate at the at the + + + align:start position:0% +the the reaction rate at the at the +inter phase of course it's going to + + align:start position:0% +inter phase of course it's going to + + + align:start position:0% +inter phase of course it's going to +depend on the number of atoms available + + align:start position:0% +depend on the number of atoms available + + + align:start position:0% +depend on the number of atoms available +per square centimeter to react uh so it + + align:start position:0% +per square centimeter to react uh so it + + + align:start position:0% +per square centimeter to react uh so it +does depend on orientation so and these + + align:start position:0% +does depend on orientation so and these + + + align:start position:0% +does depend on orientation so and these +are the dependencies just to give you + + align:start position:0% +are the dependencies just to give you + + + align:start position:0% +are the dependencies just to give you +rough numbers or our relationship 111 is + + align:start position:0% +rough numbers or our relationship 111 is + + + align:start position:0% +rough numbers or our relationship 111 is +the fastest it has the greatest number + + align:start position:0% +the fastest it has the greatest number + + + align:start position:0% +the fastest it has the greatest number +of atoms per square centimeter one one0 + + align:start position:0% +of atoms per square centimeter one one0 + + + align:start position:0% +of atoms per square centimeter one one0 +is second and the slowest is one z + + align:start position:0% +is second and the slowest is one z + + + align:start position:0% +is second and the slowest is one z +z and in fact these are the + + align:start position:0% +z and in fact these are the + + + align:start position:0% +z and in fact these are the +relationships um if we take the 111 + + align:start position:0% +relationships um if we take the 111 + + + align:start position:0% +relationships um if we take the 111 +rates uh and we divide them uh by 1.68 + + align:start position:0% +rates uh and we divide them uh by 1.68 + + + align:start position:0% +rates uh and we divide them uh by 1.68 +we get the 10 rates uh and the + + align:start position:0% +we get the 10 rates uh and the + + + align:start position:0% +we get the 10 rates uh and the +relationship between 1 one0 is in + + align:start position:0% +relationship between 1 one0 is in + + + align:start position:0% +relationship between 1 one0 is in +between and again it's related to the + + align:start position:0% +between and again it's related to the + + + align:start position:0% +between and again it's related to the +Silicon Atomic density the number of + + align:start position:0% +Silicon Atomic density the number of + + + align:start position:0% +Silicon Atomic density the number of +atoms per square centimeter that are + + align:start position:0% +atoms per square centimeter that are + + + align:start position:0% +atoms per square centimeter that are +available and you can believe that + + align:start position:0% +available and you can believe that + + + align:start position:0% +available and you can believe that +because in order to have the surface + + align:start position:0% +because in order to have the surface + + + align:start position:0% +because in order to have the surface +reaction take place silicon silicon + + align:start position:0% +reaction take place silicon silicon + + + align:start position:0% +reaction take place silicon silicon +bonds have to be broken + + align:start position:0% +bonds have to be broken + + + align:start position:0% +bonds have to be broken +um so and the number of atoms available + + align:start position:0% +um so and the number of atoms available + + + align:start position:0% +um so and the number of atoms available +is is going to be uh important in that + + align:start position:0% + + + + align:start position:0% + +case uh slide 36 um is an interesting + + align:start position:0% +case uh slide 36 um is an interesting + + + align:start position:0% +case uh slide 36 um is an interesting +example of how um even you might say + + align:start position:0% +example of how um even you might say + + + align:start position:0% +example of how um even you might say +well I only use 10 Wafers what do I care + + align:start position:0% +well I only use 10 Wafers what do I care + + + align:start position:0% +well I only use 10 Wafers what do I care +about oxidation on 11 Z well you will + + align:start position:0% +about oxidation on 11 Z well you will + + + align:start position:0% +about oxidation on 11 Z well you will +care because you often um etch a trench + + align:start position:0% +care because you often um etch a trench + + + align:start position:0% +care because you often um etch a trench +and then need to oxidize the trench and + + align:start position:0% +and then need to oxidize the trench and + + + align:start position:0% +and then need to oxidize the trench and +of course the trench has different + + align:start position:0% +of course the trench has different + + + align:start position:0% +of course the trench has different +orientations of its walls so this + + align:start position:0% +orientations of its walls so this + + + align:start position:0% +orientations of its walls so this +particular this is a um a Supreme four + + align:start position:0% +particular this is a um a Supreme four + + + align:start position:0% +particular this is a um a Supreme four +simulation of a trench that was uh + + align:start position:0% +simulation of a trench that was uh + + + align:start position:0% +simulation of a trench that was uh +etched into a 10 wafer so 10 means what + + align:start position:0% +etched into a 10 wafer so 10 means what + + + align:start position:0% +etched into a 10 wafer so 10 means what +it means the surface of this + + align:start position:0% +it means the surface of this + + + align:start position:0% +it means the surface of this +wafer this plane at the very surface is + + align:start position:0% +wafer this plane at the very surface is + + + align:start position:0% +wafer this plane at the very surface is +is is 10 the 10 direction or1 is + + align:start position:0% +is is 10 the 10 direction or1 is + + + align:start position:0% +is is 10 the 10 direction or1 is +pointing up but if once I start itching + + align:start position:0% +pointing up but if once I start itching + + + align:start position:0% +pointing up but if once I start itching +into it the planes that I expose will be + + align:start position:0% +into it the planes that I expose will be + + + align:start position:0% +into it the planes that I expose will be +different orientations right depending + + align:start position:0% +different orientations right depending + + + align:start position:0% +different orientations right depending +on how I design my trench if I etch into + + align:start position:0% +on how I design my trench if I etch into + + + align:start position:0% +on how I design my trench if I etch into +the crystal so for example um I edch a + + align:start position:0% +the crystal so for example um I edch a + + + align:start position:0% +the crystal so for example um I edch a +trench here down into the crystal the + + align:start position:0% +trench here down into the crystal the + + + align:start position:0% +trench here down into the crystal the +bottom face is one z0 because the bottom + + align:start position:0% +bottom face is one z0 because the bottom + + + align:start position:0% +bottom face is one z0 because the bottom +face is the same as as the top face the + + align:start position:0% +face is the same as as the top face the + + + align:start position:0% +face is the same as as the top face the +face of the wafer uh but the side wall + + align:start position:0% +face of the wafer uh but the side wall + + + align:start position:0% +face of the wafer uh but the side wall +this face right here the sidewall that + + align:start position:0% +this face right here the sidewall that + + + align:start position:0% +this face right here the sidewall that +I've exposed depending on how I oriented + + align:start position:0% +I've exposed depending on how I oriented + + + align:start position:0% +I've exposed depending on how I oriented +this trench which is um assumed to be uh + + align:start position:0% +this trench which is um assumed to be uh + + + align:start position:0% +this trench which is um assumed to be uh +square or rectangular the sidewall face + + align:start position:0% +square or rectangular the sidewall face + + + align:start position:0% +square or rectangular the sidewall face +could be a one one + + align:start position:0% +could be a one one + + + align:start position:0% +could be a one one +Z depending on how I orent it with + + align:start position:0% +Z depending on how I orent it with + + + align:start position:0% +Z depending on how I orent it with +respect to the flat um so um the you can + + align:start position:0% +respect to the flat um so um the you can + + + align:start position:0% +respect to the flat um so um the you can +immediately expect a different oxidation + + align:start position:0% +immediately expect a different oxidation + + + align:start position:0% +immediately expect a different oxidation +rate on this face right here from the + + align:start position:0% +rate on this face right here from the + + + align:start position:0% +rate on this face right here from the +oxidation on the bottom + + align:start position:0% +oxidation on the bottom + + + align:start position:0% +oxidation on the bottom +um and this is an example of a + + align:start position:0% +um and this is an example of a + + + align:start position:0% +um and this is an example of a +simulation that was done uh 30 minutes + + align:start position:0% +simulation that was done uh 30 minutes + + + align:start position:0% +simulation that was done uh 30 minutes +in 900 900 degrees C in water and you + + align:start position:0% +in 900 900 degrees C in water and you + + + align:start position:0% +in 900 900 degrees C in water and you +see the thicker oxide That Grew on the + + align:start position:0% +see the thicker oxide That Grew on the + + + align:start position:0% +see the thicker oxide That Grew on the +sidewall that's pretty much in this bulk + + align:start position:0% +sidewall that's pretty much in this bulk + + + align:start position:0% +sidewall that's pretty much in this bulk +region of the sidewall that's entirely + + align:start position:0% +region of the sidewall that's entirely + + + align:start position:0% +region of the sidewall that's entirely +due to the fact that it's a different + + align:start position:0% +due to the fact that it's a different + + + align:start position:0% +due to the fact that it's a different +orientation so this simulator took that + + align:start position:0% +orientation so this simulator took that + + + align:start position:0% +orientation so this simulator took that +into account it's a little bit thicker + + align:start position:0% +into account it's a little bit thicker + + + align:start position:0% +into account it's a little bit thicker +here than it is on the + + align:start position:0% +here than it is on the + + + align:start position:0% +here than it is on the +bottom what is this this weird looking + + align:start position:0% +bottom what is this this weird looking + + + align:start position:0% +bottom what is this this weird looking +Corner effect that's not orientation so + + align:start position:0% +Corner effect that's not orientation so + + + align:start position:0% +Corner effect that's not orientation so +much this actually shows a + + align:start position:0% +much this actually shows a + + + align:start position:0% +much this actually shows a +two-dimensional effect we'll we'll talk + + align:start position:0% +two-dimensional effect we'll we'll talk + + + align:start position:0% +two-dimensional effect we'll we'll talk +about next time which is a stress effect + + align:start position:0% +about next time which is a stress effect + + + align:start position:0% +about next time which is a stress effect +when you're oxidizing a corner again the + + align:start position:0% +when you're oxidizing a corner again the + + + align:start position:0% +when you're oxidizing a corner again the +oxide has to expand in a corner it's a + + align:start position:0% +oxide has to expand in a corner it's a + + + align:start position:0% +oxide has to expand in a corner it's a +little bit hard to do some expansion + + align:start position:0% +little bit hard to do some expansion + + + align:start position:0% +little bit hard to do some expansion +where it's going to turn out the + + align:start position:0% +where it's going to turn out the + + + align:start position:0% +where it's going to turn out the +oxidation rate in in these sharp Corners + + align:start position:0% +oxidation rate in in these sharp Corners + + + align:start position:0% +oxidation rate in in these sharp Corners +it's going to end up being slower due to + + align:start position:0% +it's going to end up being slower due to + + + align:start position:0% +it's going to end up being slower due to +stress so that was Tak account into the + + align:start position:0% + + + + align:start position:0% + +simulation so let me just summarize what + + align:start position:0% +simulation so let me just summarize what + + + align:start position:0% +simulation so let me just summarize what +we have from today um the basic growth + + align:start position:0% +we have from today um the basic growth + + + align:start position:0% +we have from today um the basic growth +Mech mechanism is transport through the + + align:start position:0% +Mech mechanism is transport through the + + + align:start position:0% +Mech mechanism is transport through the +oxide by diffusion and then chemical + + align:start position:0% +oxide by diffusion and then chemical + + + align:start position:0% +oxide by diffusion and then chemical +reaction at the interface as opposed to + + align:start position:0% +reaction at the interface as opposed to + + + align:start position:0% +reaction at the interface as opposed to +the Silicon doesn't come out of lattice + + align:start position:0% +the Silicon doesn't come out of lattice + + + align:start position:0% +the Silicon doesn't come out of lattice +and go up to the surface um we generally + + align:start position:0% +and go up to the surface um we generally + + + align:start position:0% +and go up to the surface um we generally +have a linear parabolic law when we have + + align:start position:0% +have a linear parabolic law when we have + + + align:start position:0% +have a linear parabolic law when we have +planer oxidation next time we're going + + align:start position:0% +planer oxidation next time we're going + + + align:start position:0% +planer oxidation next time we're going +to see there are a lot of different + + align:start position:0% +to see there are a lot of different + + + align:start position:0% +to see there are a lot of different +cases where it's non-planar and it's not + + align:start position:0% +cases where it's non-planar and it's not + + + align:start position:0% +cases where it's non-planar and it's not +just simple linear + + align:start position:0% +just simple linear + + + align:start position:0% +just simple linear +parabolic um the deal grow model isn't + + align:start position:0% +parabolic um the deal grow model isn't + + + align:start position:0% +parabolic um the deal grow model isn't +uh completely accurate in the thin oxide + + align:start position:0% +uh completely accurate in the thin oxide + + + align:start position:0% +uh completely accurate in the thin oxide +regime but it can be corrected by using + + align:start position:0% +regime but it can be corrected by using + + + align:start position:0% +regime but it can be corrected by using +uh Han and Helms or rein or you can use + + align:start position:0% +uh Han and Helms or rein or you can use + + + align:start position:0% +uh Han and Helms or rein or you can use +massud then they all can be designed to + + align:start position:0% +massud then they all can be designed to + + + align:start position:0% +massud then they all can be designed to +converge to deal grow for when you're at + + align:start position:0% +converge to deal grow for when you're at + + + align:start position:0% +converge to deal grow for when you're at +uh thinner at thicker oxide say above + + align:start position:0% +uh thinner at thicker oxide say above + + + align:start position:0% +uh thinner at thicker oxide say above +200 anrs and the growth rate varies with + + align:start position:0% +200 anrs and the growth rate varies with + + + align:start position:0% +200 anrs and the growth rate varies with +orientation 111 is the fastest and 10 uh + + align:start position:0% +orientation 111 is the fastest and 10 uh + + + align:start position:0% +orientation 111 is the fastest and 10 uh +being the + + align:start position:0% +being the + + + align:start position:0% +being the +slowest so that's mostly what I wanted + + align:start position:0% +slowest so that's mostly what I wanted + + + align:start position:0% +slowest so that's mostly what I wanted +to cover for today I have a couple + + align:start position:0% +to cover for today I have a couple + + + align:start position:0% +to cover for today I have a couple +things for you though um your + + align:start position:0% +things for you though um your + + + align:start position:0% +things for you though um your +homework is um going back so you can + + align:start position:0% +homework is um going back so you can + + + align:start position:0% +homework is um going back so you can +come up and grab your homework it's been + + align:start position:0% +come up and grab your homework it's been + + + align:start position:0% +come up and grab your homework it's been +graded uh up here homework number one + + align:start position:0% +graded uh up here homework number one + + + align:start position:0% +graded uh up here homework number one +and the solutions are also up front so + + align:start position:0% +and the solutions are also up front so + + + align:start position:0% +and the solutions are also up front so +if you can come on up and take the + + align:start position:0% +if you can come on up and take the + + + align:start position:0% +if you can come on up and take the +homework and the solutions uh from + + align:start position:0% +homework and the solutions uh from + + + align:start position:0% +homework and the solutions uh from +homework number one that's good if if + + align:start position:0% +homework number one that's good if if + + + align:start position:0% +homework number one that's good if if +you weren't here last time you didn't + + align:start position:0% +you weren't here last time you didn't + + + align:start position:0% +you weren't here last time you didn't +get to see the Intel wafer I'm going to + + align:start position:0% +get to see the Intel wafer I'm going to + + + align:start position:0% +get to see the Intel wafer I'm going to +hand it back after today so you're + + align:start position:0% +hand it back after today so you're + + + align:start position:0% +hand it back after today so you're +welcome to take a look at + + align:start position:0% + + + + align:start position:0% + +it oh these are not in any particular + + align:start position:0% + + + + align:start position:0% + +order what I need for strain on the what + + align:start position:0% +order what I need for strain on the what + + + align:start position:0% +order what I need for strain on the what +people extracted The Strain silicon yeah + + align:start position:0% +people extracted The Strain silicon yeah + + + align:start position:0% +people extracted The Strain silicon yeah +people tried Jeff tried um this pretty + + align:start position:0% +people tried Jeff tried um this pretty + + + align:start position:0% +people tried Jeff tried um this pretty +darn + + align:start position:0% +darn + + + align:start position:0% +darn +close you know a change of 1% in the + + align:start position:0% +close you know a change of 1% in the + + + align:start position:0% +close you know a change of 1% in the +last C now cuz I really haven't changed + + align:start position:0% +last C now cuz I really haven't changed + + + align:start position:0% +last C now cuz I really haven't changed +the the number of atoms per square + + align:start position:0% + + + + align:start position:0% + +centimeter what does change is as soon + + align:start position:0% +centimeter what does change is as soon + + + align:start position:0% +centimeter what does change is as soon +as you hit the SL and geranium oxidation + + align:start position:0% +as you hit the SL and geranium oxidation + + + align:start position:0% +as you hit the SL and geranium oxidation +rate goes way up + + align:start position:0% + + + + align:start position:0% + +so \ No newline at end of file diff --git a/Lgacew5BjDI.txt b/Lgacew5BjDI.txt new file mode 100644 index 0000000000000000000000000000000000000000..e4a633b87d812a78f3082c80d07723ff1595c049 --- /dev/null +++ b/Lgacew5BjDI.txt @@ -0,0 +1,403 @@ +align:start position:0% + +so we looked at the formal definition of + + align:start position:0% +so we looked at the formal definition of + + + align:start position:0% +so we looked at the formal definition of +what it means for a sequence to converge + + align:start position:0% +what it means for a sequence to converge + + + align:start position:0% +what it means for a sequence to converge +but as a practical matter how can we + + align:start position:0% +but as a practical matter how can we + + + align:start position:0% +but as a practical matter how can we +tell whether a given sequence converges + + align:start position:0% +tell whether a given sequence converges + + + align:start position:0% +tell whether a given sequence converges +or not there are two criteria that are + + align:start position:0% +or not there are two criteria that are + + + align:start position:0% +or not there are two criteria that are +the most commonly used for that purpose + + align:start position:0% +the most commonly used for that purpose + + + align:start position:0% +the most commonly used for that purpose +and it's useful to be aware of them the + + align:start position:0% +and it's useful to be aware of them the + + + align:start position:0% +and it's useful to be aware of them the +first one deals with the case where we + + align:start position:0% +first one deals with the case where we + + + align:start position:0% +first one deals with the case where we +have a sequence of numbers that keep + + align:start position:0% +have a sequence of numbers that keep + + + align:start position:0% +have a sequence of numbers that keep +increasing or at least they do not go + + align:start position:0% +increasing or at least they do not go + + + align:start position:0% +increasing or at least they do not go +down in that case those numbers may go + + align:start position:0% +down in that case those numbers may go + + + align:start position:0% +down in that case those numbers may go +up forever without any bound so if you + + align:start position:0% +up forever without any bound so if you + + + align:start position:0% +up forever without any bound so if you +look at any particular value there's + + align:start position:0% +look at any particular value there's + + + align:start position:0% +look at any particular value there's +going to be a time at which the sequence + + align:start position:0% +going to be a time at which the sequence + + + align:start position:0% +going to be a time at which the sequence +has exceeded that value in that case we + + align:start position:0% +has exceeded that value in that case we + + + align:start position:0% +has exceeded that value in that case we +say that the sequence converges to + + align:start position:0% +say that the sequence converges to + + + align:start position:0% +say that the sequence converges to +infinity but if this is not the case if + + align:start position:0% +infinity but if this is not the case if + + + align:start position:0% +infinity but if this is not the case if +it does not converge to infinity which + + align:start position:0% +it does not converge to infinity which + + + align:start position:0% +it does not converge to infinity which +means that the entries of the sequence + + align:start position:0% +means that the entries of the sequence + + + align:start position:0% +means that the entries of the sequence +are bounded they do not grow arbitrarily + + align:start position:0% +are bounded they do not grow arbitrarily + + + align:start position:0% +are bounded they do not grow arbitrarily +large then in that case it is guaranteed + + align:start position:0% +large then in that case it is guaranteed + + + align:start position:0% +large then in that case it is guaranteed +that the sequence would converge to a + + align:start position:0% +that the sequence would converge to a + + + align:start position:0% +that the sequence would converge to a +certain number this is not something + + align:start position:0% +certain number this is not something + + + align:start position:0% +certain number this is not something +that we will attempt to prove but it is + + align:start position:0% +that we will attempt to prove but it is + + + align:start position:0% +that we will attempt to prove but it is +a useful fact to know another way of + + align:start position:0% +a useful fact to know another way of + + + align:start position:0% +a useful fact to know another way of +establishing convergence is to derive + + align:start position:0% +establishing convergence is to derive + + + align:start position:0% +establishing convergence is to derive +some bounds on the distance of our + + align:start position:0% +some bounds on the distance of our + + + align:start position:0% +some bounds on the distance of our +sequence from the number that we suspect + + align:start position:0% +sequence from the number that we suspect + + + align:start position:0% +sequence from the number that we suspect +to be the limit if that distance becomes + + align:start position:0% +to be the limit if that distance becomes + + + align:start position:0% +to be the limit if that distance becomes +smaller and smaller if we can manage to + + align:start position:0% +smaller and smaller if we can manage to + + + align:start position:0% +smaller and smaller if we can manage to +bound that distance by a certain number + + align:start position:0% +bound that distance by a certain number + + + align:start position:0% +bound that distance by a certain number +and that number goes down to zero then + + align:start position:0% +and that number goes down to zero then + + + align:start position:0% +and that number goes down to zero then +it is guaranteed that since this + + align:start position:0% +it is guaranteed that since this + + + align:start position:0% +it is guaranteed that since this +distance goes down to zero that the + + align:start position:0% +distance goes down to zero that the + + + align:start position:0% +distance goes down to zero that the +sequence ái converges to a and there's a + + align:start position:0% +sequence ái converges to a and there's a + + + align:start position:0% +sequence ái converges to a and there's a +variation of this argument which is the + + align:start position:0% +variation of this argument which is the + + + align:start position:0% +variation of this argument which is the +so-called sandwich argument and it goes + + align:start position:0% +so-called sandwich argument and it goes + + + align:start position:0% +so-called sandwich argument and it goes +as follows if we have a certain sequence + + align:start position:0% +as follows if we have a certain sequence + + + align:start position:0% +as follows if we have a certain sequence +that converges to some number a and we + + align:start position:0% +that converges to some number a and we + + + align:start position:0% +that converges to some number a and we +have another sequence that converges to + + align:start position:0% +have another sequence that converges to + + + align:start position:0% +have another sequence that converges to +that same number + + align:start position:0% +that same number + + + align:start position:0% +that same number +and our sequence is somewhere in between + + align:start position:0% +and our sequence is somewhere in between + + + align:start position:0% +and our sequence is somewhere in between +then our sequence must also converge to + + align:start position:0% +then our sequence must also converge to + + + align:start position:0% +then our sequence must also converge to +that particular number a so these are + + align:start position:0% +that particular number a so these are + + + align:start position:0% +that particular number a so these are +the usual ways of quickly saying + + align:start position:0% +the usual ways of quickly saying + + + align:start position:0% +the usual ways of quickly saying +something about the convergence of a + + align:start position:0% +something about the convergence of a + + + align:start position:0% +something about the convergence of a +given sequence and we will be often + + align:start position:0% +given sequence and we will be often + + + align:start position:0% +given sequence and we will be often +using this type of argument in this + + align:start position:0% +using this type of argument in this + + + align:start position:0% +using this type of argument in this +class but without making a big fuss + + align:start position:0% +class but without making a big fuss + + + align:start position:0% +class but without making a big fuss +about them or without even referring to + + align:start position:0% +about them or without even referring to + + + align:start position:0% +about them or without even referring to +these facts in an explicit manner \ No newline at end of file diff --git a/Lm8WHM0glHE.txt b/Lm8WHM0glHE.txt new file mode 100644 index 0000000000000000000000000000000000000000..61c2a661a9df7c8b36f7a07ad801a2ce13fd23e5 --- /dev/null +++ b/Lm8WHM0glHE.txt @@ -0,0 +1,1731 @@ +align:start position:0% + +I think fun is an very important part to + + align:start position:0% +I think fun is an very important part to + + + align:start position:0% +I think fun is an very important part to +life in general and in particular work + + align:start position:0% +life in general and in particular work + + + align:start position:0% +life in general and in particular work +maybe not so common to view it that way + + align:start position:0% +maybe not so common to view it that way + + + align:start position:0% +maybe not so common to view it that way +but I think if you have fun if you enjoy + + align:start position:0% +but I think if you have fun if you enjoy + + + align:start position:0% +but I think if you have fun if you enjoy +if you're passionate about what you do + + align:start position:0% +if you're passionate about what you do + + + align:start position:0% +if you're passionate about what you do +then you'll do it well and you'll be + + align:start position:0% +then you'll do it well and you'll be + + + align:start position:0% +then you'll do it well and you'll be +super productive and people will love + + align:start position:0% +super productive and people will love + + + align:start position:0% +super productive and people will love +you for it um and so my guiding + + align:start position:0% +you for it um and so my guiding + + + align:start position:0% +you for it um and so my guiding +principle in in the research that I do + + align:start position:0% +principle in in the research that I do + + + align:start position:0% +principle in in the research that I do +has been to uh to always pursue to what + + align:start position:0% +has been to uh to always pursue to what + + + align:start position:0% +has been to uh to always pursue to what +I view as fun and sometimes it's things + + align:start position:0% +I view as fun and sometimes it's things + + + align:start position:0% +I view as fun and sometimes it's things +that are very relatable as fun like + + align:start position:0% +that are very relatable as fun like + + + align:start position:0% +that are very relatable as fun like +games and puzzles uh sometimes it's more + + align:start position:0% +games and puzzles uh sometimes it's more + + + align:start position:0% +games and puzzles uh sometimes it's more +obscure things but I personally find + + align:start position:0% +obscure things but I personally find + + + align:start position:0% +obscure things but I personally find +them really fun and maybe they're more + + align:start position:0% +them really fun and maybe they're more + + + align:start position:0% +them really fun and maybe they're more +practical um and so it's also nice to + + align:start position:0% +practical um and so it's also nice to + + + align:start position:0% +practical um and so it's also nice to +have a mixture but in teaching I think I + + align:start position:0% +have a mixture but in teaching I think I + + + align:start position:0% +have a mixture but in teaching I think I +mean I think learning should also be fun + + align:start position:0% +mean I think learning should also be fun + + + align:start position:0% +mean I think learning should also be fun +my dad raised me this way when he was + + align:start position:0% +my dad raised me this way when he was + + + align:start position:0% +my dad raised me this way when he was +homeschooling me and uh that always you + + align:start position:0% +homeschooling me and uh that always you + + + align:start position:0% +homeschooling me and uh that always you +should uh learn what you're curious + + align:start position:0% +should uh learn what you're curious + + + align:start position:0% +should uh learn what you're curious +about and uh so conversely as a teacher + + align:start position:0% +about and uh so conversely as a teacher + + + align:start position:0% +about and uh so conversely as a teacher +I want to make uh material really + + align:start position:0% +I want to make uh material really + + + align:start position:0% +I want to make uh material really +interesting and intriguing and just fun + + align:start position:0% +interesting and intriguing and just fun + + + align:start position:0% +interesting and intriguing and just fun +to learn about because I think students + + align:start position:0% +to learn about because I think students + + + align:start position:0% +to learn about because I think students +will be more excited and engage more + + align:start position:0% +will be more excited and engage more + + + align:start position:0% +will be more excited and engage more +with the material if they enjoy it seems + + align:start position:0% +with the material if they enjoy it seems + + + align:start position:0% +with the material if they enjoy it seems +natural um and so in this class I really + + align:start position:0% +natural um and so in this class I really + + + align:start position:0% +natural um and so in this class I really +tried to bring lots of fun examples I + + align:start position:0% +tried to bring lots of fun examples I + + + align:start position:0% +tried to bring lots of fun examples I +mean maybe there are some more uh + + align:start position:0% +mean maybe there are some more uh + + + align:start position:0% +mean maybe there are some more uh +serious problems that people have proved + + align:start position:0% +serious problems that people have proved + + + align:start position:0% +serious problems that people have proved +hard and then there's more entertaining + + align:start position:0% +hard and then there's more entertaining + + + align:start position:0% +hard and then there's more entertaining +problems that people have proved hard so + + align:start position:0% +problems that people have proved hard so + + + align:start position:0% +problems that people have proved hard so +I would I mean I often cover both but + + align:start position:0% +I would I mean I often cover both but + + + align:start position:0% +I would I mean I often cover both but +given the choice I'd prefer the one + + align:start position:0% +given the choice I'd prefer the one + + + align:start position:0% +given the choice I'd prefer the one +that's more entertaining and something + + align:start position:0% +that's more entertaining and something + + + align:start position:0% +that's more entertaining and something +that people can relate to like yeah I + + align:start position:0% +that people can relate to like yeah I + + + align:start position:0% +that people can relate to like yeah I +played that video game and it was really + + align:start position:0% +played that video game and it was really + + + align:start position:0% +played that video game and it was really +tough and now we can actually prove that + + align:start position:0% +tough and now we can actually prove that + + + align:start position:0% +tough and now we can actually prove that +it's tough then that's that makes it + + align:start position:0% +it's tough then that's that makes it + + + align:start position:0% +it's tough then that's that makes it +exciting um and so it's really nice I + + align:start position:0% +exciting um and so it's really nice I + + + align:start position:0% +exciting um and so it's really nice I +mean I view teaching as kind of a + + align:start position:0% +mean I view teaching as kind of a + + + align:start position:0% +mean I view teaching as kind of a +entertainment of sorts U I think it's + + align:start position:0% +entertainment of sorts U I think it's + + + align:start position:0% +entertainment of sorts U I think it's +nice to have that as a goal and if + + align:start position:0% +nice to have that as a goal and if + + + align:start position:0% +nice to have that as a goal and if +people are entertained they'll be + + align:start position:0% +people are entertained they'll be + + + align:start position:0% +people are entertained they'll be +engaged and they'll learn the material + + align:start position:0% +engaged and they'll learn the material + + + align:start position:0% +engaged and they'll learn the material +and they'll care more deeply about it + + align:start position:0% +and they'll care more deeply about it + + + align:start position:0% +and they'll care more deeply about it +and hopefully do research in the field + + align:start position:0% +and hopefully do research in the field + + + align:start position:0% +and hopefully do research in the field +and and all that I mean when I was + + align:start position:0% +and and all that I mean when I was + + + align:start position:0% +and and all that I mean when I was +younger when I was a graduate student uh + + align:start position:0% +younger when I was a graduate student uh + + + align:start position:0% +younger when I was a graduate student uh +a lot of my more senior colleagues other + + align:start position:0% +a lot of my more senior colleagues other + + + align:start position:0% +a lot of my more senior colleagues other +professors would uh warn me that it was + + align:start position:0% +professors would uh warn me that it was + + + align:start position:0% +professors would uh warn me that it was +maybe dangerous to do to pursue fun + + align:start position:0% +maybe dangerous to do to pursue fun + + + align:start position:0% +maybe dangerous to do to pursue fun +things that people would not view it as + + align:start position:0% +things that people would not view it as + + + align:start position:0% +things that people would not view it as +serious and maybe you won't get a job + + align:start position:0% +serious and maybe you won't get a job + + + align:start position:0% +serious and maybe you won't get a job +when you graduate um and I kind of + + align:start position:0% +when you graduate um and I kind of + + + align:start position:0% +when you graduate um and I kind of +ignored those + + align:start position:0% +ignored those + + + align:start position:0% +ignored those +people and uh it was it was a bit of a + + align:start position:0% +people and uh it was it was a bit of a + + + align:start position:0% +people and uh it was it was a bit of a +bold bold guess but um it worked out + + align:start position:0% +bold bold guess but um it worked out + + + align:start position:0% +bold bold guess but um it worked out +well for me and later those same people + + align:start position:0% +well for me and later those same people + + + align:start position:0% +well for me and later those same people +apologized for making that suggestion um + + align:start position:0% +apologized for making that suggestion um + + + align:start position:0% +apologized for making that suggestion um +I think again if if you're if you do + + align:start position:0% +I think again if if you're if you do + + + align:start position:0% +I think again if if you're if you do +things you're pass about you'll do them + + align:start position:0% +things you're pass about you'll do them + + + align:start position:0% +things you're pass about you'll do them +really well and you'll be very + + align:start position:0% +really well and you'll be very + + + align:start position:0% +really well and you'll be very +productive and so you can make up for + + align:start position:0% +productive and so you can make up for + + + align:start position:0% +productive and so you can make up for +the topics being more recreational by uh + + align:start position:0% +the topics being more recreational by uh + + + align:start position:0% +the topics being more recreational by uh +showing that they're really powerful and + + align:start position:0% +showing that they're really powerful and + + + align:start position:0% +showing that they're really powerful and +really deep mathematically um and that's + + align:start position:0% +really deep mathematically um and that's + + + align:start position:0% +really deep mathematically um and that's +turned out to work for me um since being + + align:start position:0% +turned out to work for me um since being + + + align:start position:0% +turned out to work for me um since being +at MIT it was again like uh you know + + align:start position:0% +at MIT it was again like uh you know + + + align:start position:0% +at MIT it was again like uh you know +will I get tenure is uh will people + + align:start position:0% +will I get tenure is uh will people + + + align:start position:0% +will I get tenure is uh will people +appreciate the fun side of things and I + + align:start position:0% +appreciate the fun side of things and I + + + align:start position:0% +appreciate the fun side of things and I +do lots of serious things in addition to + + align:start position:0% +do lots of serious things in addition to + + + align:start position:0% +do lots of serious things in addition to +lots of fun things but uh it worked out + + align:start position:0% +lots of fun things but uh it worked out + + + align:start position:0% +lots of fun things but uh it worked out +I got tenure and uh um in fact I think + + align:start position:0% +I got tenure and uh um in fact I think + + + align:start position:0% +I got tenure and uh um in fact I think +it was it's an important part of who I + + align:start position:0% +it was it's an important part of who I + + + align:start position:0% +it was it's an important part of who I +am one one analogy is to Martin Gardner + + align:start position:0% +am one one analogy is to Martin Gardner + + + align:start position:0% +am one one analogy is to Martin Gardner +uh he's sort of an idol of mine I never + + align:start position:0% +uh he's sort of an idol of mine I never + + + align:start position:0% +uh he's sort of an idol of mine I never +got to meet him although we corresponded + + align:start position:0% +got to meet him although we corresponded + + + align:start position:0% +got to meet him although we corresponded +a little bit um and he is called the + + align:start position:0% +a little bit um and he is called the + + + align:start position:0% +a little bit um and he is called the +father of recreational mathematics he + + align:start position:0% +father of recreational mathematics he + + + align:start position:0% +father of recreational mathematics he +wrote a column for Scientific American + + align:start position:0% +wrote a column for Scientific American + + + align:start position:0% +wrote a column for Scientific American +for decades and it really influenced a + + align:start position:0% +for decades and it really influenced a + + + align:start position:0% +for decades and it really influenced a +lot of uh present day mathematicians and + + align:start position:0% +lot of uh present day mathematicians and + + + align:start position:0% +lot of uh present day mathematicians and +computer scientists to get into the + + align:start position:0% +computer scientists to get into the + + + align:start position:0% +computer scientists to get into the +field because they read this column and + + align:start position:0% +field because they read this column and + + + align:start position:0% +field because they read this column and +it's talking about open problems but in + + align:start position:0% +it's talking about open problems but in + + + align:start position:0% +it's talking about open problems but in +a very accessible way he wasn't really a + + align:start position:0% +a very accessible way he wasn't really a + + + align:start position:0% +a very accessible way he wasn't really a +mathematician he just learned from + + align:start position:0% +mathematician he just learned from + + + align:start position:0% +mathematician he just learned from +mathematicians that he knew and wrote + + align:start position:0% +mathematicians that he knew and wrote + + + align:start position:0% +mathematicians that he knew and wrote +about the cool problems very accessible + + align:start position:0% +about the cool problems very accessible + + + align:start position:0% +about the cool problems very accessible +problems and fun problems uh that people + + align:start position:0% +problems and fun problems uh that people + + + align:start position:0% +problems and fun problems uh that people +were working on and what kind of + + align:start position:0% +were working on and what kind of + + + align:start position:0% +were working on and what kind of +solutions they had um and so Martin + + align:start position:0% +solutions they had um and so Martin + + + align:start position:0% +solutions they had um and so Martin +Gardner is kind of a model although I do + + align:start position:0% +Gardner is kind of a model although I do + + + align:start position:0% +Gardner is kind of a model although I do +it more in the teaching side than in the + + align:start position:0% +it more in the teaching side than in the + + + align:start position:0% +it more in the teaching side than in the +writing side of a way to engage new + + align:start position:0% +writing side of a way to engage new + + + align:start position:0% +writing side of a way to engage new +people into the field um get people + + align:start position:0% +people into the field um get people + + + align:start position:0% +people into the field um get people +excited about science and technology and + + align:start position:0% +excited about science and technology and + + + align:start position:0% +excited about science and technology and +Mathematics um and I think MIT appre + + align:start position:0% +Mathematics um and I think MIT appre + + + align:start position:0% +Mathematics um and I think MIT appre +appreciates that a lot uh that by + + align:start position:0% +appreciates that a lot uh that by + + + align:start position:0% +appreciates that a lot uh that by +working on fun problems you can reach a + + align:start position:0% +working on fun problems you can reach a + + + align:start position:0% +working on fun problems you can reach a +broad audience you know when we prove + + align:start position:0% +broad audience you know when we prove + + + align:start position:0% +broad audience you know when we prove +Super Mario Brothers is EMP complete all + + align:start position:0% +Super Mario Brothers is EMP complete all + + + align:start position:0% +Super Mario Brothers is EMP complete all +the newspapers were covering it like wow + + align:start position:0% +the newspapers were covering it like wow + + + align:start position:0% +the newspapers were covering it like wow +Hard Nintendo games really are hard and + + align:start position:0% +Hard Nintendo games really are hard and + + + align:start position:0% +Hard Nintendo games really are hard and +you know mathematicians proed this thing + + align:start position:0% +you know mathematicians proed this thing + + + align:start position:0% +you know mathematicians proed this thing +everyone knew sounds funny and so it's + + align:start position:0% +everyone knew sounds funny and so it's + + + align:start position:0% +everyone knew sounds funny and so it's +makes for good good press um and I think + + align:start position:0% +makes for good good press um and I think + + + align:start position:0% +makes for good good press um and I think +people are intrigued by oh what does + + align:start position:0% +people are intrigued by oh what does + + + align:start position:0% +people are intrigued by oh what does +that mean then they can go and read the + + align:start position:0% +that mean then they can go and read the + + + align:start position:0% +that mean then they can go and read the +paper and or take this class and it + + align:start position:0% +paper and or take this class and it + + + align:start position:0% +paper and or take this class and it +covers why how do you prove something + + align:start position:0% +covers why how do you prove something + + + align:start position:0% +covers why how do you prove something +like that and how do you actually and + + align:start position:0% +like that and how do you actually and + + + align:start position:0% +like that and how do you actually and +it's really fun to prove prove that + + align:start position:0% +it's really fun to prove prove that + + + align:start position:0% +it's really fun to prove prove that +Super Mario Brothers is hard you + + align:start position:0% +Super Mario Brothers is hard you + + + align:start position:0% +Super Mario Brothers is hard you +basically construct little levels that + + align:start position:0% +basically construct little levels that + + + align:start position:0% +basically construct little levels that +that build a computer so you build a + + align:start position:0% +that build a computer so you build a + + + align:start position:0% +that build a computer so you build a +Super Mario Brothers level that + + align:start position:0% +Super Mario Brothers level that + + + align:start position:0% +Super Mario Brothers level that +represents an entire computer and that's + + align:start position:0% +represents an entire computer and that's + + + align:start position:0% +represents an entire computer and that's +that's a fun thing to do and I think it + + align:start position:0% +that's a fun thing to do and I think it + + + align:start position:0% +that's a fun thing to do and I think it +can get a lot of people excited about + + align:start position:0% +can get a lot of people excited about + + + align:start position:0% +can get a lot of people excited about +computer science um when I first came to + + align:start position:0% +computer science um when I first came to + + + align:start position:0% +computer science um when I first came to +MIT I I Ed this as a principle to get + + align:start position:0% +MIT I I Ed this as a principle to get + + + align:start position:0% +MIT I I Ed this as a principle to get +new graduate students started so they're + + align:start position:0% +new graduate students started so they're + + + align:start position:0% +new graduate students started so they're +look they're trying to find a problem to + + align:start position:0% +look they're trying to find a problem to + + + align:start position:0% +look they're trying to find a problem to +solve they don't really know what + + align:start position:0% +solve they don't really know what + + + align:start position:0% +solve they don't really know what +they're interested in so often I'll + + align:start position:0% +they're interested in so often I'll + + + align:start position:0% +they're interested in so often I'll +suggest a game or a puzzle hey let's + + align:start position:0% +suggest a game or a puzzle hey let's + + + align:start position:0% +suggest a game or a puzzle hey let's +prove this hard one of the first ones + + align:start position:0% +prove this hard one of the first ones + + + align:start position:0% +prove this hard one of the first ones +was Tetris that was done with two MIT + + align:start position:0% +was Tetris that was done with two MIT + + + align:start position:0% +was Tetris that was done with two MIT +students uh back in 2003 I think just + + align:start position:0% +students uh back in 2003 I think just + + + align:start position:0% +students uh back in 2003 I think just +after I started I was like you I've + + align:start position:0% +after I started I was like you I've + + + align:start position:0% +after I started I was like you I've +always been curious about Tetris it + + align:start position:0% +always been curious about Tetris it + + + align:start position:0% +always been curious about Tetris it +seems really tricky um and then together + + align:start position:0% +seems really tricky um and then together + + + align:start position:0% +seems really tricky um and then together +we we proved that it was hard and that + + align:start position:0% +we we proved that it was hard and that + + + align:start position:0% +we we proved that it was hard and that +was their first paper and it got them + + align:start position:0% +was their first paper and it got them + + + align:start position:0% +was their first paper and it got them +kind of psyched up and ready to solve + + align:start position:0% +kind of psyched up and ready to solve + + + align:start position:0% +kind of psyched up and ready to solve +more problems you know they don't do + + align:start position:0% +more problems you know they don't do + + + align:start position:0% +more problems you know they don't do +hardness of games anymore uh but it was + + align:start position:0% +hardness of games anymore uh but it was + + + align:start position:0% +hardness of games anymore uh but it was +like a nice warmup to build their + + align:start position:0% +like a nice warmup to build their + + + align:start position:0% +like a nice warmup to build their +confidence and show that they can do + + align:start position:0% +confidence and show that they can do + + + align:start position:0% +confidence and show that they can do +this uh so I think a lot of these + + align:start position:0% +this uh so I think a lot of these + + + align:start position:0% +this uh so I think a lot of these +problems are it's hardness make easy you + + align:start position:0% +problems are it's hardness make easy you + + + align:start position:0% +problems are it's hardness make easy you +it becomes quite accessible uh one of + + align:start position:0% +it becomes quite accessible uh one of + + + align:start position:0% +it becomes quite accessible uh one of +the things that really made me happy + + align:start position:0% +the things that really made me happy + + + align:start position:0% +the things that really made me happy +about this class is I I have teach a lot + + align:start position:0% +about this class is I I have teach a lot + + + align:start position:0% +about this class is I I have teach a lot +of advanced Theory classes and each one + + align:start position:0% +of advanced Theory classes and each one + + + align:start position:0% +of advanced Theory classes and each one +of them has a final project at the end + + align:start position:0% +of them has a final project at the end + + + align:start position:0% +of them has a final project at the end +and this class uh also had a final + + align:start position:0% +and this class uh also had a final + + + align:start position:0% +and this class uh also had a final +project and there many types you can do + + align:start position:0% +project and there many types you can do + + + align:start position:0% +project and there many types you can do +uh but the type I'm always most excited + + align:start position:0% +uh but the type I'm always most excited + + + align:start position:0% +uh but the type I'm always most excited +about is solve an open problem and in + + align:start position:0% +about is solve an open problem and in + + + align:start position:0% +about is solve an open problem and in +this hardness proof class uh most of the + + align:start position:0% +this hardness proof class uh most of the + + + align:start position:0% +this hardness proof class uh most of the +students solved an open problem compared + + align:start position:0% +students solved an open problem compared + + + align:start position:0% +students solved an open problem compared +to any other class I've taught or seen + + align:start position:0% +to any other class I've taught or seen + + + align:start position:0% +to any other class I've taught or seen +um many more students solved open + + align:start position:0% +um many more students solved open + + + align:start position:0% +um many more students solved open +problems because they a lot of them are + + align:start position:0% +problems because they a lot of them are + + + align:start position:0% +problems because they a lot of them are +relatively accessible you can take a + + align:start position:0% +relatively accessible you can take a + + + align:start position:0% +relatively accessible you can take a +game or a puzzle that just you like + + align:start position:0% +game or a puzzle that just you like + + + align:start position:0% +game or a puzzle that just you like +playing and you have expertise in but no + + align:start position:0% +playing and you have expertise in but no + + + align:start position:0% +playing and you have expertise in but no +one else has tried to analyze + + align:start position:0% +one else has tried to analyze + + + align:start position:0% +one else has tried to analyze +mathematically and now suddenly you can + + align:start position:0% +mathematically and now suddenly you can + + + align:start position:0% +mathematically and now suddenly you can +bring these new tools to it and uh prove + + align:start position:0% +bring these new tools to it and uh prove + + + align:start position:0% +bring these new tools to it and uh prove +your result and write it paper fun is + + align:start position:0% +your result and write it paper fun is + + + align:start position:0% +your result and write it paper fun is +like the hook that gets you excited + + align:start position:0% +like the hook that gets you excited + + + align:start position:0% +like the hook that gets you excited +about the the research the problems the + + align:start position:0% +about the the research the problems the + + + align:start position:0% +about the the research the problems the +and the material so uh you know we + + align:start position:0% +and the material so uh you know we + + + align:start position:0% +and the material so uh you know we +analyze a lot of uh games and puzzles + + align:start position:0% +analyze a lot of uh games and puzzles + + + align:start position:0% +analyze a lot of uh games and puzzles +and most of them to kind of keep it + + align:start position:0% +and most of them to kind of keep it + + + align:start position:0% +and most of them to kind of keep it +interesting we analyze real world games + + align:start position:0% +interesting we analyze real world games + + + align:start position:0% +interesting we analyze real world games +and puzzles like video games that people + + align:start position:0% +and puzzles like video games that people + + + align:start position:0% +and puzzles like video games that people +play um and one example is Super Mario + + align:start position:0% +play um and one example is Super Mario + + + align:start position:0% +play um and one example is Super Mario +Brothers where we can prove that it's NP + + align:start position:0% +Brothers where we can prove that it's NP + + + align:start position:0% +Brothers where we can prove that it's NP +hard to figure out whether you can solve + + align:start position:0% +hard to figure out whether you can solve + + + align:start position:0% +hard to figure out whether you can solve +a given level so there's no good + + align:start position:0% +a given level so there's no good + + + align:start position:0% +a given level so there's no good +algorithm to given a Super Mario + + align:start position:0% +algorithm to given a Super Mario + + + align:start position:0% +algorithm to given a Super Mario +Brothers level figure out how to solve + + align:start position:0% +Brothers level figure out how to solve + + + align:start position:0% +Brothers level figure out how to solve +it um this I guess becomes particularly + + align:start position:0% +it um this I guess becomes particularly + + + align:start position:0% +it um this I guess becomes particularly +relevant uh once you can make your own + + align:start position:0% +relevant uh once you can make your own + + + align:start position:0% +relevant uh once you can make your own +custom levels so with the the upcoming + + align:start position:0% +custom levels so with the the upcoming + + + align:start position:0% +custom levels so with the the upcoming +release of Super Mario Maker uh now + + align:start position:0% +release of Super Mario Maker uh now + + + align:start position:0% +release of Super Mario Maker uh now +people can actually build their own + + align:start position:0% +people can actually build their own + + + align:start position:0% +people can actually build their own +levels uh this will be really fun from a + + align:start position:0% +levels uh this will be really fun from a + + + align:start position:0% +levels uh this will be really fun from a +research perspective because we can take + + align:start position:0% +research perspective because we can take + + + align:start position:0% +research perspective because we can take +all the levels that we've designed we + + align:start position:0% +all the levels that we've designed we + + + align:start position:0% +all the levels that we've designed we +when we design them we just arrange them + + align:start position:0% +when we design them we just arrange them + + + align:start position:0% +when we design them we just arrange them +as pixel art so that you can see the + + align:start position:0% +as pixel art so that you can see the + + + align:start position:0% +as pixel art so that you can see the +level but you can't actually experience + + align:start position:0% +level but you can't actually experience + + + align:start position:0% +level but you can't actually experience +the level um and in order to actually + + align:start position:0% +the level um and in order to actually + + + align:start position:0% +the level um and in order to actually +experience the level you'd have to + + align:start position:0% +experience the level you'd have to + + + align:start position:0% +experience the level you'd have to +modify the ROM of the game and it's very + + align:start position:0% +modify the ROM of the game and it's very + + + align:start position:0% +modify the ROM of the game and it's very +tricky and technically uh annoying and + + align:start position:0% +tricky and technically uh annoying and + + + align:start position:0% +tricky and technically uh annoying and +maybe also illegal to do that um Super + + align:start position:0% +maybe also illegal to do that um Super + + + align:start position:0% +maybe also illegal to do that um Super +Mario Maker suddenly Mak makes it + + align:start position:0% +Mario Maker suddenly Mak makes it + + + align:start position:0% +Mario Maker suddenly Mak makes it +accessible that everyone can make custom + + align:start position:0% +accessible that everyone can make custom + + + align:start position:0% +accessible that everyone can make custom +levels I think it also makes the results + + align:start position:0% +levels I think it also makes the results + + + align:start position:0% +levels I think it also makes the results +more relevant it says hey if you + + align:start position:0% +more relevant it says hey if you + + + align:start position:0% +more relevant it says hey if you +download a new level figuring out how to + + align:start position:0% +download a new level figuring out how to + + + align:start position:0% +download a new level figuring out how to +solve it is going to be a real Challenge + + align:start position:0% +solve it is going to be a real Challenge + + + align:start position:0% +solve it is going to be a real Challenge +and I think this is a big reason why + + align:start position:0% +and I think this is a big reason why + + + align:start position:0% +and I think this is a big reason why +people find video games fun uh because + + align:start position:0% +people find video games fun uh because + + + align:start position:0% +people find video games fun uh because +they find them challenging I think if a + + align:start position:0% +they find them challenging I think if a + + + align:start position:0% +they find them challenging I think if a +game is too easy there are exceptions + + align:start position:0% +game is too easy there are exceptions + + + align:start position:0% +game is too easy there are exceptions +but if a game is too easy it gets boring + + align:start position:0% +but if a game is too easy it gets boring + + + align:start position:0% +but if a game is too easy it gets boring +pretty quickly um and when there's this + + align:start position:0% +pretty quickly um and when there's this + + + align:start position:0% +pretty quickly um and when there's this +nice uh when you can set the difficulty + + align:start position:0% +nice uh when you can set the difficulty + + + align:start position:0% +nice uh when you can set the difficulty +of the problem so it's not impossible + + align:start position:0% +of the problem so it's not impossible + + + align:start position:0% +of the problem so it's not impossible +but at least it's a big challenge to to + + align:start position:0% +but at least it's a big challenge to to + + + align:start position:0% +but at least it's a big challenge to to +solve it um I think that's where you get + + align:start position:0% +solve it um I think that's where you get + + + align:start position:0% +solve it um I think that's where you get +The Sweet Spot in having fun and this + + align:start position:0% +The Sweet Spot in having fun and this + + + align:start position:0% +The Sweet Spot in having fun and this +whole area of hardness proofs gives you + + align:start position:0% +whole area of hardness proofs gives you + + + align:start position:0% +whole area of hardness proofs gives you +a mathematical way of analyzing games + + align:start position:0% +a mathematical way of analyzing games + + + align:start position:0% +a mathematical way of analyzing games +and puzzles to show yeah they are really + + align:start position:0% +and puzzles to show yeah they are really + + + align:start position:0% +and puzzles to show yeah they are really +challenging they're hard even for + + align:start position:0% +challenging they're hard even for + + + align:start position:0% +challenging they're hard even for +computers to solve them so for humans it + + align:start position:0% +computers to solve them so for humans it + + + align:start position:0% +computers to solve them so for humans it +could be also really challenging \ No newline at end of file diff --git a/Lo_LSZ_R1w4.txt b/Lo_LSZ_R1w4.txt new file mode 100644 index 0000000000000000000000000000000000000000..4a73847b98e61118cc397b8074d235fbdfeed5c1 --- /dev/null +++ b/Lo_LSZ_R1w4.txt @@ -0,0 +1,9640 @@ +align:start position:0% + +we have to finish + + align:start position:0% +we have to finish + + + align:start position:0% +we have to finish +our discussion of evolution and then + + align:start position:0% +our discussion of evolution and then + + + align:start position:0% +our discussion of evolution and then +we'll start talking about + + align:start position:0% +we'll start talking about + + + align:start position:0% +we'll start talking about +anatomy + + align:start position:0% +anatomy + + + align:start position:0% +anatomy +question + + align:start position:0% + + + + align:start position:0% + +the function of the notochord + + align:start position:0% + + + + align:start position:0% + +you know that's a good question why did + + align:start position:0% +you know that's a good question why did + + + align:start position:0% +you know that's a good question why did +it evolve in the first place + + align:start position:0% +it evolve in the first place + + + align:start position:0% +it evolve in the first place +it gives the body some rigidity you know + + align:start position:0% +it gives the body some rigidity you know + + + align:start position:0% +it gives the body some rigidity you know +and but you know i'd be all i'd just be + + align:start position:0% +and but you know i'd be all i'd just be + + + align:start position:0% +and but you know i'd be all i'd just be +making it up + + align:start position:0% + + + + align:start position:0% + +what is the animal what would it be like + + align:start position:0% +what is the animal what would it be like + + + align:start position:0% +what is the animal what would it be like +if it didn't have the notochord it would + + align:start position:0% +if it didn't have the notochord it would + + + align:start position:0% +if it didn't have the notochord it would +be a a worm + + align:start position:0% +be a a worm + + + align:start position:0% +be a a worm +you know + + align:start position:0% +you know + + + align:start position:0% +you know +and it looks like a worm when it first + + align:start position:0% +and it looks like a worm when it first + + + align:start position:0% +and it looks like a worm when it first +evolves but it's a chordate it's got a + + align:start position:0% +evolves but it's a chordate it's got a + + + align:start position:0% +evolves but it's a chordate it's got a +notochord + + align:start position:0% + + + + align:start position:0% + +we can say a lot more than that about it + + align:start position:0% +we can say a lot more than that about it + + + align:start position:0% +we can say a lot more than that about it +its roles it plays + + align:start position:0% +its roles it plays + + + align:start position:0% +its roles it plays +clear roles in the evolution of the + + align:start position:0% +clear roles in the evolution of the + + + align:start position:0% +clear roles in the evolution of the +brain or inductive influences from an + + align:start position:0% +brain or inductive influences from an + + + align:start position:0% +brain or inductive influences from an +autocard that affect the overlying + + align:start position:0% +autocard that affect the overlying + + + align:start position:0% +autocard that affect the overlying +nervous system and we'll talk about that + + align:start position:0% +nervous system and we'll talk about that + + + align:start position:0% +nervous system and we'll talk about that +when we talk about development + + align:start position:0% + + + + align:start position:0% + +okay let's just go back a little bit + + align:start position:0% +okay let's just go back a little bit + + + align:start position:0% +okay let's just go back a little bit +we're talking about evolution of the + + align:start position:0% +we're talking about evolution of the + + + align:start position:0% +we're talking about evolution of the +brain + + align:start position:0% +brain + + + align:start position:0% +brain +remember + + align:start position:0% +remember + + + align:start position:0% +remember +we looked at the + + align:start position:0% +we looked at the + + + align:start position:0% +we looked at the +simplest possible neural tube in a + + align:start position:0% +simplest possible neural tube in a + + + align:start position:0% +simplest possible neural tube in a +chordate in amphioxus + + align:start position:0% +chordate in amphioxus + + + align:start position:0% +chordate in amphioxus +and we talked about the evolution of + + align:start position:0% +and we talked about the evolution of + + + align:start position:0% +and we talked about the evolution of +forward locomotion + + align:start position:0% +forward locomotion + + + align:start position:0% +forward locomotion +that led to the + + align:start position:0% +that led to the + + + align:start position:0% +that led to the +need for head receptors as head + + align:start position:0% +need for head receptors as head + + + align:start position:0% +need for head receptors as head +receptors evolved they led to an + + align:start position:0% +receptors evolved they led to an + + + align:start position:0% +receptors evolved they led to an +enlargement of the anterior ends we call + + align:start position:0% +enlargement of the anterior ends we call + + + align:start position:0% +enlargement of the anterior ends we call +that the brain + + align:start position:0% + + + + align:start position:0% + +there were expansions of + + align:start position:0% +there were expansions of + + + align:start position:0% +there were expansions of +structures in the brain that received + + align:start position:0% +structures in the brain that received + + + align:start position:0% +structures in the brain that received +inputs from the head receptors + + align:start position:0% + + + + align:start position:0% + +give me an example of inputs that come + + align:start position:0% +give me an example of inputs that come + + + align:start position:0% +give me an example of inputs that come +in + + align:start position:0% +in + + + align:start position:0% +in +through a cranial nerve + + align:start position:0% + + + + align:start position:0% + +rather than a spinal nerve + + align:start position:0% + + + + align:start position:0% + +vision yes + + align:start position:0% +vision yes + + + align:start position:0% +vision yes +v1 + + align:start position:0% +v1 + + + align:start position:0% +v1 +what's the one that comes in most + + align:start position:0% +what's the one that comes in most + + + align:start position:0% +what's the one that comes in most +anterior way up at the rostral line + + align:start position:0% + + + + align:start position:0% + +well factory you see it here + + align:start position:0% +well factory you see it here + + + align:start position:0% +well factory you see it here +because + + align:start position:0% + + + + align:start position:0% + +and that's where we'll start today + + align:start position:0% +and that's where we'll start today + + + align:start position:0% +and that's where we'll start today +the forebrain + + align:start position:0% +the forebrain + + + align:start position:0% +the forebrain +expanded initially + + align:start position:0% + + + + align:start position:0% + +we're talking about forebrain not the + + align:start position:0% +we're talking about forebrain not the + + + align:start position:0% +we're talking about forebrain not the +whole brain because of the influence of + + align:start position:0% +whole brain because of the influence of + + + align:start position:0% +whole brain because of the influence of +olfaction and the importance of + + align:start position:0% +olfaction and the importance of + + + align:start position:0% +olfaction and the importance of +olfaction + + align:start position:0% +olfaction + + + align:start position:0% +olfaction +or approach and avoidance functions + + align:start position:0% +or approach and avoidance functions + + + align:start position:0% +or approach and avoidance functions +feeding mating behavior predator + + align:start position:0% +feeding mating behavior predator + + + align:start position:0% +feeding mating behavior predator +avoidance so forth + + align:start position:0% +avoidance so forth + + + align:start position:0% +avoidance so forth +the links to the local motor system were + + align:start position:0% +the links to the local motor system were + + + align:start position:0% +the links to the local motor system were +not made by direct connections initially + + align:start position:0% +not made by direct connections initially + + + align:start position:0% +not made by direct connections initially +they were made through links through the + + align:start position:0% +they were made through links through the + + + align:start position:0% +they were made through links through the +midbrain + + align:start position:0% +midbrain + + + align:start position:0% +midbrain +we know we're guessing that from studies + + align:start position:0% +we know we're guessing that from studies + + + align:start position:0% +we know we're guessing that from studies +of primitive + + align:start position:0% +of primitive + + + align:start position:0% +of primitive +animals + + align:start position:0% +animals + + + align:start position:0% +animals +primitive vertebrates + + align:start position:0% + + + + align:start position:0% + +so that's what we're showing here + + align:start position:0% + + + + align:start position:0% + +i added those words at the top + + align:start position:0% +i added those words at the top + + + align:start position:0% +i added those words at the top +the expansions continue then with the + + align:start position:0% +the expansions continue then with the + + + align:start position:0% +the expansions continue then with the +development of structures in between + + align:start position:0% +development of structures in between + + + align:start position:0% +development of structures in between +sensory and motor structures + + align:start position:0% +sensory and motor structures + + + align:start position:0% +sensory and motor structures +for + + align:start position:0% +for + + + align:start position:0% +for +various functions + + align:start position:0% +various functions + + + align:start position:0% +various functions +maintaining stabilities stability in + + align:start position:0% +maintaining stabilities stability in + + + align:start position:0% +maintaining stabilities stability in +space + + align:start position:0% +space + + + align:start position:0% +space +approach and avoidance functions and + + align:start position:0% +approach and avoidance functions and + + + align:start position:0% +approach and avoidance functions and +that + + align:start position:0% +that + + + align:start position:0% +that +led to the evolution of these + + align:start position:0% +led to the evolution of these + + + align:start position:0% +led to the evolution of these +specialized structures particularly in + + align:start position:0% +specialized structures particularly in + + + align:start position:0% +specialized structures particularly in +the midbrain + + align:start position:0% + + + + align:start position:0% + +showing here the + + align:start position:0% + + + + align:start position:0% + +fish with an expanded midbrain as well + + align:start position:0% +fish with an expanded midbrain as well + + + align:start position:0% +fish with an expanded midbrain as well +as cerebellum important the midbrain was + + align:start position:0% +as cerebellum important the midbrain was + + + align:start position:0% +as cerebellum important the midbrain was +connected to the cerebellum + + align:start position:0% +connected to the cerebellum + + + align:start position:0% +connected to the cerebellum +for coordinating + + align:start position:0% +for coordinating + + + align:start position:0% +for coordinating +movements + + align:start position:0% + + + + align:start position:0% + +and the midbrain expanded with the + + align:start position:0% +and the midbrain expanded with the + + + align:start position:0% +and the midbrain expanded with the +evolution of distance receptors + + align:start position:0% +evolution of distance receptors + + + align:start position:0% +evolution of distance receptors +other than olfaction the olfaction could + + align:start position:0% +other than olfaction the olfaction could + + + align:start position:0% +other than olfaction the olfaction could +be called a distance receptor but + + align:start position:0% +be called a distance receptor but + + + align:start position:0% +be called a distance receptor but +the real distance receptors are + + align:start position:0% +the real distance receptors are + + + align:start position:0% +the real distance receptors are +division and audition which has many + + align:start position:0% +division and audition which has many + + + align:start position:0% +division and audition which has many +advantages for + + align:start position:0% +advantages for + + + align:start position:0% +advantages for +speed sensory acuity + + align:start position:0% +speed sensory acuity + + + align:start position:0% +speed sensory acuity +early warning + + align:start position:0% +early warning + + + align:start position:0% +early warning +and for anticipating things that are + + align:start position:0% +and for anticipating things that are + + + align:start position:0% +and for anticipating things that are +about to happen + + align:start position:0% +about to happen + + + align:start position:0% +about to happen +so when that evolved on the motor side + + align:start position:0% +so when that evolved on the motor side + + + align:start position:0% +so when that evolved on the motor side +you have to be able to turn the + + align:start position:0% +you have to be able to turn the + + + align:start position:0% +you have to be able to turn the +receptors + + align:start position:0% +receptors + + + align:start position:0% +receptors +which means + + align:start position:0% +which means + + + align:start position:0% +which means +orienting movements + + align:start position:0% +orienting movements + + + align:start position:0% +orienting movements +and the midbrain became particularly + + align:start position:0% +and the midbrain became particularly + + + align:start position:0% +and the midbrain became particularly +important for that and i'm showing here + + align:start position:0% +important for that and i'm showing here + + + align:start position:0% +important for that and i'm showing here +in the picture + + align:start position:0% +in the picture + + + align:start position:0% +in the picture +fibers coming from the eye coming into + + align:start position:0% +fibers coming from the eye coming into + + + align:start position:0% +fibers coming from the eye coming into +the midbrain + + align:start position:0% +the midbrain + + + align:start position:0% +the midbrain +it's interesting the eye did not evolve + + align:start position:0% +it's interesting the eye did not evolve + + + align:start position:0% +it's interesting the eye did not evolve +initially from the midbrain it + + align:start position:0% +initially from the midbrain it + + + align:start position:0% +initially from the midbrain it +originated as an out pouching of the + + align:start position:0% +originated as an out pouching of the + + + align:start position:0% +originated as an out pouching of the +twin brain + + align:start position:0% +twin brain + + + align:start position:0% +twin brain +and probably played even more + + align:start position:0% +and probably played even more + + + align:start position:0% +and probably played even more +had more primitive functions initially + + align:start position:0% +had more primitive functions initially + + + align:start position:0% +had more primitive functions initially +coordinating activity with the day night + + align:start position:0% +coordinating activity with the day night + + + align:start position:0% +coordinating activity with the day night +cycle just detecting light + + align:start position:0% +cycle just detecting light + + + align:start position:0% +cycle just detecting light +but once the connection to the midbrain + + align:start position:0% +but once the connection to the midbrain + + + align:start position:0% +but once the connection to the midbrain +was formed then it took on + + align:start position:0% +was formed then it took on + + + align:start position:0% +was formed then it took on +the role + + align:start position:0% +the role + + + align:start position:0% +the role +that required an expansion + + align:start position:0% +that required an expansion + + + align:start position:0% +that required an expansion +the sensory analyzers of the midbrain + + align:start position:0% +the sensory analyzers of the midbrain + + + align:start position:0% +the sensory analyzers of the midbrain +tectum + + align:start position:0% + + + + align:start position:0% + +and the midbrain then became the major + + align:start position:0% +and the midbrain then became the major + + + align:start position:0% +and the midbrain then became the major +we could call it a sentinel detecting + + align:start position:0% +we could call it a sentinel detecting + + + align:start position:0% +we could call it a sentinel detecting +predators + + align:start position:0% +predators + + + align:start position:0% +predators +it also played an important role in + + align:start position:0% +it also played an important role in + + + align:start position:0% +it also played an important role in +orienting and feeding + + align:start position:0% + + + + align:start position:0% + +okay then finally my fifth stage here + + align:start position:0% +okay then finally my fifth stage here + + + align:start position:0% +okay then finally my fifth stage here +expansion of the forebrain again + + align:start position:0% +expansion of the forebrain again + + + align:start position:0% +expansion of the forebrain again +but now + + align:start position:0% +but now + + + align:start position:0% +but now +not because of olfaction anymore + + align:start position:0% +not because of olfaction anymore + + + align:start position:0% +not because of olfaction anymore +but because non-olfactory systems + + align:start position:0% +but because non-olfactory systems + + + align:start position:0% +but because non-olfactory systems +invaded the end brain + + align:start position:0% + + + + align:start position:0% + +and they did so not just they initially + + align:start position:0% +and they did so not just they initially + + + align:start position:0% +and they did so not just they initially +invaded the corpus triatum + + align:start position:0% +invaded the corpus triatum + + + align:start position:0% +invaded the corpus triatum +very important structure in + + align:start position:0% +very important structure in + + + align:start position:0% +very important structure in +plasticity of habit formation and so + + align:start position:0% +plasticity of habit formation and so + + + align:start position:0% +plasticity of habit formation and so +forth important in + + align:start position:0% +forth important in + + + align:start position:0% +forth important in +both feeding approach and avoidance + + align:start position:0% +both feeding approach and avoidance + + + align:start position:0% +both feeding approach and avoidance +functions and feeding and predator + + align:start position:0% +functions and feeding and predator + + + align:start position:0% +functions and feeding and predator +avoidance + + align:start position:0% + + + + align:start position:0% + +but in learning + + align:start position:0% + + + + align:start position:0% + +but then something very interesting + + align:start position:0% +but then something very interesting + + + align:start position:0% +but then something very interesting +happened + + align:start position:0% + + + + align:start position:0% + +the corpus triatum was not a cortical + + align:start position:0% +the corpus triatum was not a cortical + + + align:start position:0% +the corpus triatum was not a cortical +structure was not a layered structure at + + align:start position:0% +structure was not a layered structure at + + + align:start position:0% +structure was not a layered structure at +the surface of the brain + + align:start position:0% + + + + align:start position:0% + +like the cortex of the olfactory system + + align:start position:0% +like the cortex of the olfactory system + + + align:start position:0% +like the cortex of the olfactory system +was + + align:start position:0% +was + + + align:start position:0% +was +but when that cortex was began to be + + align:start position:0% +but when that cortex was began to be + + + align:start position:0% +but when that cortex was began to be +invaded by these other sensory systems + + align:start position:0% +invaded by these other sensory systems + + + align:start position:0% +invaded by these other sensory systems +vision and audition and + + align:start position:0% +vision and audition and + + + align:start position:0% +vision and audition and +somatic sensation + + align:start position:0% +somatic sensation + + + align:start position:0% +somatic sensation +it led to a great expansion of the + + align:start position:0% +it led to a great expansion of the + + + align:start position:0% +it led to a great expansion of the +forebrain the end at the end brain part + + align:start position:0% +forebrain the end at the end brain part + + + align:start position:0% +forebrain the end at the end brain part +of the forebrain very rustled into the + + align:start position:0% +of the forebrain very rustled into the + + + align:start position:0% +of the forebrain very rustled into the +brain + + align:start position:0% + + + + align:start position:0% + +and i'm showing here + + align:start position:0% +and i'm showing here + + + align:start position:0% +and i'm showing here +a projection from + + align:start position:0% +a projection from + + + align:start position:0% +a projection from +the tectum + + align:start position:0% +the tectum + + + align:start position:0% +the tectum +carrying visual and auditory information + + align:start position:0% +carrying visual and auditory information + + + align:start position:0% +carrying visual and auditory information +into the forebrain through the tween + + align:start position:0% +into the forebrain through the tween + + + align:start position:0% +into the forebrain through the tween +brain i show a connection there in the + + align:start position:0% +brain i show a connection there in the + + + align:start position:0% +brain i show a connection there in the +twin brain then a connection into the + + align:start position:0% +twin brain then a connection into the + + + align:start position:0% +twin brain then a connection into the +end brain now that kind of connection + + align:start position:0% +end brain now that kind of connection + + + align:start position:0% +end brain now that kind of connection +initially went into the corpus triadon + + align:start position:0% +initially went into the corpus triadon + + + align:start position:0% +initially went into the corpus triadon +okay + + align:start position:0% + + + + align:start position:0% + +and i mention here that + + align:start position:0% + + + + align:start position:0% + +what was happening on the motor side but + + align:start position:0% +what was happening on the motor side but + + + align:start position:0% +what was happening on the motor side but +that didn't happen so much until the end + + align:start position:0% +that didn't happen so much until the end + + + align:start position:0% +that didn't happen so much until the end +brain expanded + + align:start position:0% +brain expanded + + + align:start position:0% +brain expanded +i mentioned this before elaboration of + + align:start position:0% +i mentioned this before elaboration of + + + align:start position:0% +i mentioned this before elaboration of +other things that were going on + + align:start position:0% +other things that were going on + + + align:start position:0% +other things that were going on +elaboration of complex programs for goal + + align:start position:0% +elaboration of complex programs for goal + + + align:start position:0% +elaboration of complex programs for goal +directed activities + + align:start position:0% +directed activities + + + align:start position:0% +directed activities +the so-called fixed action patterns + + align:start position:0% + + + + align:start position:0% + +if i put a red star here it probably + + align:start position:0% +if i put a red star here it probably + + + align:start position:0% +if i put a red star here it probably +means i've changed the slide a little + + align:start position:0% +means i've changed the slide a little + + + align:start position:0% +means i've changed the slide a little +bit since you have your printout + + align:start position:0% +bit since you have your printout + + + align:start position:0% +bit since you have your printout +i probably added here + + align:start position:0% + + + + align:start position:0% + +this phrase the great mammalian + + align:start position:0% +this phrase the great mammalian + + + align:start position:0% +this phrase the great mammalian +elaborations just to stress that + + align:start position:0% +elaborations just to stress that + + + align:start position:0% +elaborations just to stress that +the additions to the brain that happen + + align:start position:0% +the additions to the brain that happen + + + align:start position:0% +the additions to the brain that happen +for reward driven learning and habit + + align:start position:0% +for reward driven learning and habit + + + align:start position:0% +for reward driven learning and habit +formation the corpus triatum + + align:start position:0% +formation the corpus triatum + + + align:start position:0% +formation the corpus triatum +which was closely linked to neocortex + + align:start position:0% +which was closely linked to neocortex + + + align:start position:0% +which was closely linked to neocortex +was something that happened in mammals + + align:start position:0% +was something that happened in mammals + + + align:start position:0% +was something that happened in mammals +especially because of the evolution of + + align:start position:0% +especially because of the evolution of + + + align:start position:0% +especially because of the evolution of +neocortex okay + + align:start position:0% + + + + align:start position:0% + +oh yes there's certainly reward + + align:start position:0% +oh yes there's certainly reward + + + align:start position:0% +oh yes there's certainly reward +functions + + align:start position:0% +functions + + + align:start position:0% +functions +in non-mammalian animals also + + align:start position:0% +in non-mammalian animals also + + + align:start position:0% +in non-mammalian animals also +but + + align:start position:0% +but + + + align:start position:0% +but +it was the expansion of the neocortex + + align:start position:0% +it was the expansion of the neocortex + + + align:start position:0% +it was the expansion of the neocortex +which elaborated the possibilities of + + align:start position:0% +which elaborated the possibilities of + + + align:start position:0% +which elaborated the possibilities of +input to those structures that led to + + align:start position:0% +input to those structures that led to + + + align:start position:0% +input to those structures that led to +the biggest expansion + + align:start position:0% + + + + align:start position:0% + +that's a good question he asked me if + + align:start position:0% +that's a good question he asked me if + + + align:start position:0% +that's a good question he asked me if +non-mammals go for things like cocaine + + align:start position:0% +non-mammals go for things like cocaine + + + align:start position:0% +non-mammals go for things like cocaine +which is a + + align:start position:0% +which is a + + + align:start position:0% +which is a +these kinds of addictions are + + align:start position:0% +these kinds of addictions are + + + align:start position:0% +these kinds of addictions are +you could say they're + + align:start position:0% +you could say they're + + + align:start position:0% +you could say they're +acquired pathologies of the reward + + align:start position:0% +acquired pathologies of the reward + + + align:start position:0% +acquired pathologies of the reward +system the motivational system + + align:start position:0% +system the motivational system + + + align:start position:0% +system the motivational system +it's a good question i'm not sure but i + + align:start position:0% +it's a good question i'm not sure but i + + + align:start position:0% +it's a good question i'm not sure but i +would guess they probably do + + align:start position:0% + + + + align:start position:0% + +okay so what systems + + align:start position:0% +okay so what systems + + + align:start position:0% +okay so what systems +evolved to modulate + + align:start position:0% +evolved to modulate + + + align:start position:0% +evolved to modulate +other brand systems and resp + + align:start position:0% +other brand systems and resp + + + align:start position:0% +other brand systems and resp +for motivational control visceral and + + align:start position:0% +for motivational control visceral and + + + align:start position:0% +for motivational control visceral and +social needs + + align:start position:0% + + + + align:start position:0% + +these are the structures that you should + + align:start position:0% +these are the structures that you should + + + align:start position:0% +these are the structures that you should +think of there i put them in blue here + + align:start position:0% + + + + align:start position:0% + +these are the functions we're talking + + align:start position:0% +these are the functions we're talking + + + align:start position:0% +these are the functions we're talking +about control of motivation elaboration + + align:start position:0% +about control of motivation elaboration + + + align:start position:0% +about control of motivation elaboration +of hierarchies of goals and + + align:start position:0% +of hierarchies of goals and + + + align:start position:0% +of hierarchies of goals and +communication of + + align:start position:0% +communication of + + + align:start position:0% +communication of +needs to other members of the species + + align:start position:0% + + + + align:start position:0% + +and the main structures that evolved + + align:start position:0% +and the main structures that evolved + + + align:start position:0% +and the main structures that evolved +here were the hypothalamus + + align:start position:0% +here were the hypothalamus + + + align:start position:0% +here were the hypothalamus +which were connected to the lower + + align:start position:0% +which were connected to the lower + + + align:start position:0% +which were connected to the lower +structures that did that + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +then the structures in the end brain + + align:start position:0% + + + + align:start position:0% + +that we're most closely connected to the + + align:start position:0% +that we're most closely connected to the + + + align:start position:0% +that we're most closely connected to the +hypothalamus and we call those + + align:start position:0% +hypothalamus and we call those + + + align:start position:0% +hypothalamus and we call those +structures the limbic system of the + + align:start position:0% +structures the limbic system of the + + + align:start position:0% +structures the limbic system of the +forebrain + + align:start position:0% + + + + align:start position:0% + +and then along with that of the further + + align:start position:0% +and then along with that of the further + + + align:start position:0% +and then along with that of the further +elaboration of the end brain and this + + align:start position:0% +elaboration of the end brain and this + + + align:start position:0% +elaboration of the end brain and this +happened really only with neocortex + + align:start position:0% +happened really only with neocortex + + + align:start position:0% +happened really only with neocortex +systems for anticipating + + align:start position:0% +systems for anticipating + + + align:start position:0% +systems for anticipating +and predicting things on the sensory + + align:start position:0% +and predicting things on the sensory + + + align:start position:0% +and predicting things on the sensory +side images that could simulate objects + + align:start position:0% +side images that could simulate objects + + + align:start position:0% +side images that could simulate objects +and events on the motor side planning of + + align:start position:0% +and events on the motor side planning of + + + align:start position:0% +and events on the motor side planning of +actions these were non-reflex functions + + align:start position:0% +actions these were non-reflex functions + + + align:start position:0% +actions these were non-reflex functions +that i talked about at the end of the + + align:start position:0% +that i talked about at the end of the + + + align:start position:0% +that i talked about at the end of the +introductory lectures + + align:start position:0% + + + + align:start position:0% + +and here + + align:start position:0% +and here + + + align:start position:0% +and here +it was the neocortex that played the + + align:start position:0% +it was the neocortex that played the + + + align:start position:0% +it was the neocortex that played the +primary role in fact at these higher + + align:start position:0% +primary role in fact at these higher + + + align:start position:0% +primary role in fact at these higher +functions cognitive functions + + align:start position:0% +functions cognitive functions + + + align:start position:0% +functions cognitive functions +the structures that expanded the most in + + align:start position:0% +the structures that expanded the most in + + + align:start position:0% +the structures that expanded the most in +the neocortex where the + + align:start position:0% +the neocortex where the + + + align:start position:0% +the neocortex where the +so-called association areas those are + + align:start position:0% +so-called association areas those are + + + align:start position:0% +so-called association areas those are +the areas that in us + + align:start position:0% +the areas that in us + + + align:start position:0% +the areas that in us +occupy the largest part of our neocortex + + align:start position:0% +occupy the largest part of our neocortex + + + align:start position:0% +occupy the largest part of our neocortex +along with that all parts of the + + align:start position:0% +along with that all parts of the + + + align:start position:0% +along with that all parts of the +neocortex are connected the corpus + + align:start position:0% +neocortex are connected the corpus + + + align:start position:0% +neocortex are connected the corpus +triadom + + align:start position:0% +triadom + + + align:start position:0% +triadom +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and the parts that get those connections + + align:start position:0% +and the parts that get those connections + + + align:start position:0% +and the parts that get those connections +from the cortex have expanded also so + + align:start position:0% +from the cortex have expanded also so + + + align:start position:0% +from the cortex have expanded also so +it's not just one thing that expands + + align:start position:0% +it's not just one thing that expands + + + align:start position:0% +it's not just one thing that expands +many things expand in parallel + + align:start position:0% + + + + align:start position:0% + +and before that the end brain of the of + + align:start position:0% +and before that the end brain of the of + + + align:start position:0% +and before that the end brain of the of +the animals leading to mammals was + + align:start position:0% +the animals leading to mammals was + + + align:start position:0% +the animals leading to mammals was +dominated by olfaction the paleocortex + + align:start position:0% +dominated by olfaction the paleocortex + + + align:start position:0% +dominated by olfaction the paleocortex +and more ancient parts of the corpus + + align:start position:0% +and more ancient parts of the corpus + + + align:start position:0% +and more ancient parts of the corpus +tree atom and you can see that by + + align:start position:0% +tree atom and you can see that by + + + align:start position:0% +tree atom and you can see that by +looking at the brains + + align:start position:0% +looking at the brains + + + align:start position:0% +looking at the brains +of these + + align:start position:0% +of these + + + align:start position:0% +of these +of various species + + align:start position:0% + + + + align:start position:0% + +and i'm showing here this expansion of + + align:start position:0% +and i'm showing here this expansion of + + + align:start position:0% +and i'm showing here this expansion of +the in-brain + + align:start position:0% +the in-brain + + + align:start position:0% +the in-brain +i put here a picture based on brains of + + align:start position:0% +i put here a picture based on brains of + + + align:start position:0% +i put here a picture based on brains of +fish + + align:start position:0% + + + + align:start position:0% + +showing the smaller end brain little + + align:start position:0% +showing the smaller end brain little + + + align:start position:0% +showing the smaller end brain little +tween brain + + align:start position:0% +tween brain + + + align:start position:0% +tween brain +and then a larger brain stem + + align:start position:0% +and then a larger brain stem + + + align:start position:0% +and then a larger brain stem +midbrain and hindbrain + + align:start position:0% +midbrain and hindbrain + + + align:start position:0% +midbrain and hindbrain +larger than the end brain but then + + align:start position:0% +larger than the end brain but then + + + align:start position:0% +larger than the end brain but then +in mammals + + align:start position:0% +in mammals + + + align:start position:0% +in mammals +you have the evolution of neocortex + + align:start position:0% +you have the evolution of neocortex + + + align:start position:0% +you have the evolution of neocortex +that's the structure that's + + align:start position:0% +that's the structure that's + + + align:start position:0% +that's the structure that's +pretty much unique with mammals although + + align:start position:0% +pretty much unique with mammals although + + + align:start position:0% +pretty much unique with mammals although +higher birds + + align:start position:0% +higher birds + + + align:start position:0% +higher birds +also have structures like neocortex + + align:start position:0% +also have structures like neocortex + + + align:start position:0% +also have structures like neocortex +but it doesn't have the same structure + + align:start position:0% +but it doesn't have the same structure + + + align:start position:0% +but it doesn't have the same structure +as the neocortex of mammals + + align:start position:0% +as the neocortex of mammals + + + align:start position:0% +as the neocortex of mammals +okay but they do have + + align:start position:0% +okay but they do have + + + align:start position:0% +okay but they do have +they have structures we don't have that + + align:start position:0% +they have structures we don't have that + + + align:start position:0% +they have structures we don't have that +that are similarly connected + + align:start position:0% +that are similarly connected + + + align:start position:0% +that are similarly connected +okay + + align:start position:0% + + + + align:start position:0% + +the relative size of structures i'm + + align:start position:0% +the relative size of structures i'm + + + align:start position:0% +the relative size of structures i'm +showing here would be + + align:start position:0% +showing here would be + + + align:start position:0% +showing here would be +well in proportion about the brain of a + + align:start position:0% +well in proportion about the brain of a + + + align:start position:0% +well in proportion about the brain of a +rodent + + align:start position:0% +rodent + + + align:start position:0% +rodent +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so this is just + + align:start position:0% +so this is just + + + align:start position:0% +so this is just +earlier expansion of the cortex and then + + align:start position:0% +earlier expansion of the cortex and then + + + align:start position:0% +earlier expansion of the cortex and then +i'm showing here along with it + + align:start position:0% +i'm showing here along with it + + + align:start position:0% +i'm showing here along with it +expanded the cerebellum + + align:start position:0% +expanded the cerebellum + + + align:start position:0% +expanded the cerebellum +okay + + align:start position:0% +okay + + + align:start position:0% +okay +parts the more lateral parts of the + + align:start position:0% +parts the more lateral parts of the + + + align:start position:0% +parts the more lateral parts of the +cerebellum + + align:start position:0% +cerebellum + + + align:start position:0% +cerebellum +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and also i'm not showing here at all the + + align:start position:0% +and also i'm not showing here at all the + + + align:start position:0% +and also i'm not showing here at all the +neostriatum + + align:start position:0% + + + + align:start position:0% + +okay now before we go to a more + + align:start position:0% +okay now before we go to a more + + + align:start position:0% +okay now before we go to a more +systematic coverage of neuroanatomy + + align:start position:0% +systematic coverage of neuroanatomy + + + align:start position:0% +systematic coverage of neuroanatomy +let's just talk a little bit about + + align:start position:0% +let's just talk a little bit about + + + align:start position:0% +let's just talk a little bit about +what's happening to the brain evolution + + align:start position:0% +what's happening to the brain evolution + + + align:start position:0% +what's happening to the brain evolution +if we just look at the weight + + align:start position:0% + + + + align:start position:0% + +first of all + + align:start position:0% +first of all + + + align:start position:0% +first of all +we don't have the heaviest brains + + align:start position:0% +we don't have the heaviest brains + + + align:start position:0% +we don't have the heaviest brains +the heaviest brains are in animals that + + align:start position:0% +the heaviest brains are in animals that + + + align:start position:0% +the heaviest brains are in animals that +are larger than us especially much + + align:start position:0% +are larger than us especially much + + + align:start position:0% +are larger than us especially much +larger like whales + + align:start position:0% +larger like whales + + + align:start position:0% +larger like whales +elephants + + align:start position:0% +elephants + + + align:start position:0% +elephants +if you look at here brainwave is on the + + align:start position:0% +if you look at here brainwave is on the + + + align:start position:0% +if you look at here brainwave is on the +coordinate here + + align:start position:0% + + + + align:start position:0% + +see we here have at the top the blue + + align:start position:0% +see we here have at the top the blue + + + align:start position:0% +see we here have at the top the blue +whale + + align:start position:0% +whale + + + align:start position:0% +whale +also the elephant + + align:start position:0% +also the elephant + + + align:start position:0% +also the elephant +uh the porpoise and here's modern humans + + align:start position:0% +uh the porpoise and here's modern humans + + + align:start position:0% +uh the porpoise and here's modern humans +okay + + align:start position:0% +okay + + + align:start position:0% +okay +but if we were it's plotted here on a + + align:start position:0% +but if we were it's plotted here on a + + + align:start position:0% +but if we were it's plotted here on a +against body weight + + align:start position:0% +against body weight + + + align:start position:0% +against body weight +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and if you look at that graph + + align:start position:0% +and if you look at that graph + + + align:start position:0% +and if you look at that graph +and + + align:start position:0% + + + + align:start position:0% + +you'll see that + + align:start position:0% +you'll see that + + + align:start position:0% +you'll see that +humans are the furthest from + + align:start position:0% + + + + align:start position:0% + +this line here + + align:start position:0% + + + + align:start position:0% + +in proportion to body weight + + align:start position:0% +in proportion to body weight + + + align:start position:0% +in proportion to body weight +the brain is larger than humans okay + + align:start position:0% +the brain is larger than humans okay + + + align:start position:0% +the brain is larger than humans okay +there are actually a few exceptions + + align:start position:0% + + + + align:start position:0% + +porpoises are + + align:start position:0% +porpoises are + + + align:start position:0% +porpoises are +probably + + align:start position:0% +probably + + + align:start position:0% +probably +very close to us partly because they + + align:start position:0% +very close to us partly because they + + + align:start position:0% +very close to us partly because they +don't have limbs + + align:start position:0% +don't have limbs + + + align:start position:0% +don't have limbs +so their spinal cords don't have the + + align:start position:0% +so their spinal cords don't have the + + + align:start position:0% +so their spinal cords don't have the +enlargements + + align:start position:0% +enlargements + + + align:start position:0% +enlargements +with the extra neurons supporting the + + align:start position:0% +with the extra neurons supporting the + + + align:start position:0% +with the extra neurons supporting the +limbs okay so that distorts that picture + + align:start position:0% +limbs okay so that distorts that picture + + + align:start position:0% +limbs okay so that distorts that picture +a little bit + + align:start position:0% +a little bit + + + align:start position:0% +a little bit +and + + align:start position:0% +and + + + align:start position:0% +and +there are + + align:start position:0% +there are + + + align:start position:0% +there are +there are some little rodent-like + + align:start position:0% +there are some little rodent-like + + + align:start position:0% +there are some little rodent-like +animals that have a pretty high brand + + align:start position:0% +animals that have a pretty high brand + + + align:start position:0% +animals that have a pretty high brand +body weight ratio but we don't talk much + + align:start position:0% +body weight ratio but we don't talk much + + + align:start position:0% +body weight ratio but we don't talk much +about them + + align:start position:0% + + + + align:start position:0% + +here if you look at the various animal + + align:start position:0% +here if you look at the various animal + + + align:start position:0% +here if you look at the various animal +groups + + align:start position:0% +groups + + + align:start position:0% +groups +on this that kind of graph + + align:start position:0% +on this that kind of graph + + + align:start position:0% +on this that kind of graph +you'll see that the mammals + + align:start position:0% + + + + align:start position:0% + +are different + + align:start position:0% +are different + + + align:start position:0% +are different +although there's overlap with + + align:start position:0% +although there's overlap with + + + align:start position:0% +although there's overlap with +birds and other animals + + align:start position:0% +birds and other animals + + + align:start position:0% +birds and other animals +and the more primitive vertebrates + + align:start position:0% +and the more primitive vertebrates + + + align:start position:0% +and the more primitive vertebrates +are the furthest to the + + align:start position:0% +are the furthest to the + + + align:start position:0% +are the furthest to the +lower right here + + align:start position:0% + + + + align:start position:0% + +now we know some of the factors that + + align:start position:0% +now we know some of the factors that + + + align:start position:0% +now we know some of the factors that +affect brain size + + align:start position:0% + + + + align:start position:0% + +not just intelligence + + align:start position:0% +not just intelligence + + + align:start position:0% +not just intelligence +by a long shot + + align:start position:0% +by a long shot + + + align:start position:0% +by a long shot +okay + + align:start position:0% +okay + + + align:start position:0% +okay +i'll say a little bit more about that + + align:start position:0% +i'll say a little bit more about that + + + align:start position:0% +i'll say a little bit more about that +in a minute here + + align:start position:0% + + + + align:start position:0% + +first of all + + align:start position:0% +first of all + + + align:start position:0% +first of all +these terms the notochord + + align:start position:0% +these terms the notochord + + + align:start position:0% +these terms the notochord +you see it spelled in both these ways + + align:start position:0% +you see it spelled in both these ways + + + align:start position:0% +you see it spelled in both these ways +the h or without the h and i'll accept + + align:start position:0% +the h or without the h and i'll accept + + + align:start position:0% +the h or without the h and i'll accept +either one + + align:start position:0% +either one + + + align:start position:0% +either one +but the first one is actually the + + align:start position:0% +but the first one is actually the + + + align:start position:0% +but the first one is actually the +supposedly the proper one + + align:start position:0% +supposedly the proper one + + + align:start position:0% +supposedly the proper one +but don't spell spinal cord with the h + + align:start position:0% +but don't spell spinal cord with the h + + + align:start position:0% +but don't spell spinal cord with the h +okay + + align:start position:0% + + + + align:start position:0% + +only the it is a cord + + align:start position:0% +only the it is a cord + + + align:start position:0% +only the it is a cord +okay + + align:start position:0% +okay + + + align:start position:0% +okay +cord + + align:start position:0% + + + + align:start position:0% + +let's say a little bit about the + + align:start position:0% +let's say a little bit about the + + + align:start position:0% +let's say a little bit about the +relationship of + + align:start position:0% +relationship of + + + align:start position:0% +relationship of +development or ontogeny the development + + align:start position:0% +development or ontogeny the development + + + align:start position:0% +development or ontogeny the development +of the individual + + align:start position:0% + + + + align:start position:0% + +comparing that to uh + + align:start position:0% +comparing that to uh + + + align:start position:0% +comparing that to uh +difference in species phylogeny + + align:start position:0% +difference in species phylogeny + + + align:start position:0% +difference in species phylogeny +we want to know whether development can + + align:start position:0% +we want to know whether development can + + + align:start position:0% +we want to know whether development can +tell us anything about evolution we + + align:start position:0% +tell us anything about evolution we + + + align:start position:0% +tell us anything about evolution we +there's a popular phrase that ontogeny + + align:start position:0% +there's a popular phrase that ontogeny + + + align:start position:0% +there's a popular phrase that ontogeny +recaps capitulates phylogeny what does + + align:start position:0% +recaps capitulates phylogeny what does + + + align:start position:0% +recaps capitulates phylogeny what does +that mean + + align:start position:0% +that mean + + + align:start position:0% +that mean +okay + + align:start position:0% +okay + + + align:start position:0% +okay +what it means is that the earlier the + + align:start position:0% +what it means is that the earlier the + + + align:start position:0% +what it means is that the earlier the +stage of embryonic development the + + align:start position:0% +stage of embryonic development the + + + align:start position:0% +stage of embryonic development the +greater the resemblance of different + + align:start position:0% +greater the resemblance of different + + + align:start position:0% +greater the resemblance of different +species okay + + align:start position:0% +species okay + + + align:start position:0% +species okay +so if you take say the brain of a pig or + + align:start position:0% +so if you take say the brain of a pig or + + + align:start position:0% +so if you take say the brain of a pig or +the brain of a monkey compared to the + + align:start position:0% +the brain of a monkey compared to the + + + align:start position:0% +the brain of a monkey compared to the +brain of humans at very early stages of + + align:start position:0% +brain of humans at very early stages of + + + align:start position:0% +brain of humans at very early stages of +development they all look the same + + align:start position:0% +development they all look the same + + + align:start position:0% +development they all look the same +okay + + align:start position:0% + + + + align:start position:0% + +as you get later + + align:start position:0% +as you get later + + + align:start position:0% +as you get later +you get more and more divergence okay + + align:start position:0% +you get more and more divergence okay + + + align:start position:0% +you get more and more divergence okay +let's look at the pictures from + + align:start position:0% +let's look at the pictures from + + + align:start position:0% +let's look at the pictures from +romanus + + align:start position:0% +romanus + + + align:start position:0% +romanus + + align:start position:0% + + + align:start position:0% +okay + + align:start position:0% +okay + + + align:start position:0% +okay +here he's showing + + align:start position:0% +here he's showing + + + align:start position:0% +here he's showing +at a very early stage + + align:start position:0% + + + + align:start position:0% + +fish salamander a tortoise chick a hog a + + align:start position:0% +fish salamander a tortoise chick a hog a + + + align:start position:0% +fish salamander a tortoise chick a hog a +calf a rabbit and a human + + align:start position:0% +calf a rabbit and a human + + + align:start position:0% +calf a rabbit and a human +we see very similar + + align:start position:0% +we see very similar + + + align:start position:0% +we see very similar +appearances + + align:start position:0% +appearances + + + align:start position:0% +appearances +in all these different vertebrates + + align:start position:0% +in all these different vertebrates + + + align:start position:0% +in all these different vertebrates +in early stages + + align:start position:0% +in early stages + + + align:start position:0% +in early stages +but now + + align:start position:0% +but now + + + align:start position:0% +but now +middle stages + + align:start position:0% +middle stages + + + align:start position:0% +middle stages +later + + align:start position:0% +later + + + align:start position:0% +later +you see that already the fish and the + + align:start position:0% +you see that already the fish and the + + + align:start position:0% +you see that already the fish and the +salamander looking very different + + align:start position:0% +salamander looking very different + + + align:start position:0% +salamander looking very different +okay + + align:start position:0% + + + + align:start position:0% + +but + + align:start position:0% +but + + + align:start position:0% +but +the reptile here + + align:start position:0% +the reptile here + + + align:start position:0% +the reptile here +the bird + + align:start position:0% +the bird + + + align:start position:0% +the bird +and all the mammals still look pretty + + align:start position:0% +and all the mammals still look pretty + + + align:start position:0% +and all the mammals still look pretty +similar + + align:start position:0% +similar + + + align:start position:0% +similar +there are some small differences + + align:start position:0% +there are some small differences + + + align:start position:0% +there are some small differences +beginning to appear + + align:start position:0% +beginning to appear + + + align:start position:0% +beginning to appear +and then when we get much later in + + align:start position:0% +and then when we get much later in + + + align:start position:0% +and then when we get much later in +development and we're still here pretty + + align:start position:0% +development and we're still here pretty + + + align:start position:0% +development and we're still here pretty +early in gestation for humans + + align:start position:0% +early in gestation for humans + + + align:start position:0% +early in gestation for humans +we see more differences + + align:start position:0% +we see more differences + + + align:start position:0% +we see more differences +right now if we had a monkey in there or + + align:start position:0% +right now if we had a monkey in there or + + + align:start position:0% +right now if we had a monkey in there or +an ape + + align:start position:0% +an ape + + + align:start position:0% +an ape +we would say that this stage the human + + align:start position:0% +we would say that this stage the human + + + align:start position:0% +we would say that this stage the human +still looks pretty much the same it's + + align:start position:0% +still looks pretty much the same it's + + + align:start position:0% +still looks pretty much the same it's +these primates + + align:start position:0% +these primates + + + align:start position:0% +these primates +okay + + align:start position:0% + + + + align:start position:0% + +it seems that + + align:start position:0% + + + + align:start position:0% + +they diverge later in development if + + align:start position:0% +they diverge later in development if + + + align:start position:0% +they diverge later in development if +they diverge later in evolution that's + + align:start position:0% +they diverge later in evolution that's + + + align:start position:0% +they diverge later in evolution that's +the correlation that seems to hold + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +it's just to remind you that + + align:start position:0% + + + + align:start position:0% + +my outline of high priority behavioral + + align:start position:0% +my outline of high priority behavioral + + + align:start position:0% +my outline of high priority behavioral +demands + + align:start position:0% + + + + align:start position:0% + +uh it's based only mainly on + + align:start position:0% +uh it's based only mainly on + + + align:start position:0% +uh it's based only mainly on +studies of evolution and behavior + + align:start position:0% +studies of evolution and behavior + + + align:start position:0% +studies of evolution and behavior +comparative studies of behavior + + align:start position:0% +comparative studies of behavior + + + align:start position:0% +comparative studies of behavior +and i've correlated that with changes in + + align:start position:0% +and i've correlated that with changes in + + + align:start position:0% +and i've correlated that with changes in +anatomy + + align:start position:0% +anatomy + + + align:start position:0% +anatomy +i emphasize that it's speculative here + + align:start position:0% +i emphasize that it's speculative here + + + align:start position:0% +i emphasize that it's speculative here +but it is based on a lot of information + + align:start position:0% +but it is based on a lot of information + + + align:start position:0% +but it is based on a lot of information +and i support it with illustrations from + + align:start position:0% +and i support it with illustrations from + + + align:start position:0% +and i support it with illustrations from +comparative anatomy + + align:start position:0% +comparative anatomy + + + align:start position:0% +comparative anatomy +so these are the various stages we've + + align:start position:0% +so these are the various stages we've + + + align:start position:0% +so these are the various stages we've +already reviewed that today so i won't + + align:start position:0% +already reviewed that today so i won't + + + align:start position:0% +already reviewed that today so i won't +go over this now + + align:start position:0% +go over this now + + + align:start position:0% +go over this now +i just want to remind you that we have + + align:start position:0% +i just want to remind you that we have + + + align:start position:0% +i just want to remind you that we have +these data that i showed you before that + + align:start position:0% +these data that i showed you before that + + + align:start position:0% +these data that i showed you before that +show the importance of + + align:start position:0% +show the importance of + + + align:start position:0% +show the importance of +relative size + + align:start position:0% +relative size + + + align:start position:0% +relative size +or specialized functions + + align:start position:0% +or specialized functions + + + align:start position:0% +or specialized functions +remember + + align:start position:0% +remember + + + align:start position:0% +remember +the expansions of the hindbrain here + + align:start position:0% +the expansions of the hindbrain here + + + align:start position:0% +the expansions of the hindbrain here +with specialized taste functions + + align:start position:0% + + + + align:start position:0% + +in these fish + + align:start position:0% +in these fish + + + align:start position:0% +in these fish +but i just want to mention some other + + align:start position:0% +but i just want to mention some other + + + align:start position:0% +but i just want to mention some other +specializations so you want + + align:start position:0% +specializations so you want + + + align:start position:0% +specializations so you want +assume that it's only these fish that + + align:start position:0% +assume that it's only these fish that + + + align:start position:0% +assume that it's only these fish that +give us this + + align:start position:0% +give us this + + + align:start position:0% +give us this +some fish have electro reception we + + align:start position:0% +some fish have electro reception we + + + align:start position:0% +some fish have electro reception we +don't have that but they some as many + + align:start position:0% +don't have that but they some as many + + + align:start position:0% +don't have that but they some as many +fish have this they can detect + + align:start position:0% +fish have this they can detect + + + align:start position:0% +fish have this they can detect +disturbances in the electric field that + + align:start position:0% +disturbances in the electric field that + + + align:start position:0% +disturbances in the electric field that +they generate around their body with the + + align:start position:0% +they generate around their body with the + + + align:start position:0% +they generate around their body with the +electric organs + + align:start position:0% +electric organs + + + align:start position:0% +electric organs +in the mormon fish this has led to an + + align:start position:0% +in the mormon fish this has led to an + + + align:start position:0% +in the mormon fish this has led to an +enormous expansion of cerebellum so if + + align:start position:0% +enormous expansion of cerebellum so if + + + align:start position:0% +enormous expansion of cerebellum so if +you open the skull you see a cerebellum + + align:start position:0% +you open the skull you see a cerebellum + + + align:start position:0% +you open the skull you see a cerebellum +it covers everything it's it's like when + + align:start position:0% +it covers everything it's it's like when + + + align:start position:0% +it covers everything it's it's like when +you open a human skull you see is the + + align:start position:0% +you open a human skull you see is the + + + align:start position:0% +you open a human skull you see is the +neocortex okay + + align:start position:0% + + + + align:start position:0% + +we still don't fully understand + + align:start position:0% +we still don't fully understand + + + align:start position:0% +we still don't fully understand +exactly what the cerebellum is doing + + align:start position:0% +exactly what the cerebellum is doing + + + align:start position:0% +exactly what the cerebellum is doing +in those animals or even in us + + align:start position:0% + + + + align:start position:0% + +that we have some ideas about it + + align:start position:0% +that we have some ideas about it + + + align:start position:0% +that we have some ideas about it +if you take + + align:start position:0% +if you take + + + align:start position:0% +if you take +let's look at another specialization + + align:start position:0% +let's look at another specialization + + + align:start position:0% +let's look at another specialization +what is a pit viper it's a snake + + align:start position:0% +what is a pit viper it's a snake + + + align:start position:0% +what is a pit viper it's a snake +that has a specialized pit organ + + align:start position:0% +that has a specialized pit organ + + + align:start position:0% +that has a specialized pit organ +okay + + align:start position:0% +okay + + + align:start position:0% +okay +on its + + align:start position:0% +on its + + + align:start position:0% +on its +head okay + + align:start position:0% +head okay + + + align:start position:0% +head okay +means it it has infrared detectors those + + align:start position:0% +means it it has infrared detectors those + + + align:start position:0% +means it it has infrared detectors those +pin organs + + align:start position:0% +pin organs + + + align:start position:0% +pin organs +so in total darkness + + align:start position:0% +so in total darkness + + + align:start position:0% +so in total darkness +a snake can detect your presence or the + + align:start position:0% +a snake can detect your presence or the + + + align:start position:0% +a snake can detect your presence or the +presence of anything warm + + align:start position:0% +presence of anything warm + + + align:start position:0% +presence of anything warm +okay because it can detect infrared + + align:start position:0% +okay because it can detect infrared + + + align:start position:0% +okay because it can detect infrared +radiation + + align:start position:0% +radiation + + + align:start position:0% +radiation +okay + + align:start position:0% + + + + align:start position:0% + +and we have to we can do that too but + + align:start position:0% +and we have to we can do that too but + + + align:start position:0% +and we have to we can do that too but +only if we invent a machine to do it + + align:start position:0% +only if we invent a machine to do it + + + align:start position:0% +only if we invent a machine to do it +okay + + align:start position:0% +okay + + + align:start position:0% +okay +bats and corpuses + + align:start position:0% +bats and corpuses + + + align:start position:0% +bats and corpuses +have echolocation so that's another + + align:start position:0% +have echolocation so that's another + + + align:start position:0% +have echolocation so that's another +specialized sense that's led to an + + align:start position:0% +specialized sense that's led to an + + + align:start position:0% +specialized sense that's led to an +expansion in their auditory system in + + align:start position:0% +expansion in their auditory system in + + + align:start position:0% +expansion in their auditory system in +midbrain + + align:start position:0% +midbrain + + + align:start position:0% +midbrain +controlling orientation movements + + align:start position:0% +controlling orientation movements + + + align:start position:0% +controlling orientation movements +they also have expanded there are some + + align:start position:0% +they also have expanded there are some + + + align:start position:0% +they also have expanded there are some +studies of + + align:start position:0% +studies of + + + align:start position:0% +studies of +bat and neocortex from expanded auditory + + align:start position:0% +bat and neocortex from expanded auditory + + + align:start position:0% +bat and neocortex from expanded auditory +regions in the neocortex as well + + align:start position:0% + + + + align:start position:0% + +primates + + align:start position:0% +primates + + + align:start position:0% +primates +what's characteristic most + + align:start position:0% +what's characteristic most + + + align:start position:0% +what's characteristic most +characteristic the primase vision + + align:start position:0% +characteristic the primase vision + + + align:start position:0% +characteristic the primase vision +high visual acuity + + align:start position:0% +high visual acuity + + + align:start position:0% +high visual acuity +learned object recognition that's led to + + align:start position:0% +learned object recognition that's led to + + + align:start position:0% +learned object recognition that's led to +expansion of visual cortical areas if + + align:start position:0% +expansion of visual cortical areas if + + + align:start position:0% +expansion of visual cortical areas if +you look at the brain of a barista's + + align:start position:0% +you look at the brain of a barista's + + + align:start position:0% +you look at the brain of a barista's +monkey + + align:start position:0% +monkey + + + align:start position:0% +monkey +i mean it looks like more than half of + + align:start position:0% +i mean it looks like more than half of + + + align:start position:0% +i mean it looks like more than half of +the brain is occupied by areas related + + align:start position:0% +the brain is occupied by areas related + + + align:start position:0% +the brain is occupied by areas related +to vision + + align:start position:0% + + + + align:start position:0% + +in rodents the comparable thing would be + + align:start position:0% +in rodents the comparable thing would be + + + align:start position:0% +in rodents the comparable thing would be +representation of the whiskers their + + align:start position:0% +representation of the whiskers their + + + align:start position:0% +representation of the whiskers their +face the debris okay + + align:start position:0% +face the debris okay + + + align:start position:0% +face the debris okay +they have specialized somatosensory + + align:start position:0% +they have specialized somatosensory + + + align:start position:0% +they have specialized somatosensory +systems and they're frequently studied + + align:start position:0% +systems and they're frequently studied + + + align:start position:0% +systems and they're frequently studied +in neuroscience because of this + + align:start position:0% + + + + align:start position:0% + +so there are other examples + + align:start position:0% +so there are other examples + + + align:start position:0% +so there are other examples +i'll mention some a few other behavioral + + align:start position:0% +i'll mention some a few other behavioral + + + align:start position:0% +i'll mention some a few other behavioral +specializations these are all correlated + + align:start position:0% +specializations these are all correlated + + + align:start position:0% +specializations these are all correlated +with + + align:start position:0% +with + + + align:start position:0% +with +elaborations in the brain + + align:start position:0% +elaborations in the brain + + + align:start position:0% +elaborations in the brain +the hand we mentioned vision in the + + align:start position:0% +the hand we mentioned vision in the + + + align:start position:0% +the hand we mentioned vision in the +primates but also they have specialized + + align:start position:0% +primates but also they have specialized + + + align:start position:0% +primates but also they have specialized +hands okay + + align:start position:0% +hands okay + + + align:start position:0% +hands okay +but so do raccoons + + align:start position:0% +but so do raccoons + + + align:start position:0% +but so do raccoons +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and humans of course especially which + + align:start position:0% +and humans of course especially which + + + align:start position:0% +and humans of course especially which +requires a lot of tactile acuity and + + align:start position:0% +requires a lot of tactile acuity and + + + align:start position:0% +requires a lot of tactile acuity and +fine motor control both + + align:start position:0% +fine motor control both + + + align:start position:0% +fine motor control both +and these lead to expansions are + + align:start position:0% +and these lead to expansions are + + + align:start position:0% +and these lead to expansions are +correlated with expansions in the + + align:start position:0% +correlated with expansions in the + + + align:start position:0% +correlated with expansions in the +somatic sensory motor cortex and in the + + align:start position:0% +somatic sensory motor cortex and in the + + + align:start position:0% +somatic sensory motor cortex and in the +cerebellar hemispheres connected with + + align:start position:0% +cerebellar hemispheres connected with + + + align:start position:0% +cerebellar hemispheres connected with +those areas of the hemispheres + + align:start position:0% + + + + align:start position:0% + +other animals have this this monkey + + align:start position:0% +other animals have this this monkey + + + align:start position:0% +other animals have this this monkey +also has a special specialized tail a + + align:start position:0% +also has a special specialized tail a + + + align:start position:0% +also has a special specialized tail a +prehensile tail + + align:start position:0% +prehensile tail + + + align:start position:0% +prehensile tail +and he's got something we don't have at + + align:start position:0% +and he's got something we don't have at + + + align:start position:0% +and he's got something we don't have at +all expanded tail representations and + + align:start position:0% +all expanded tail representations and + + + align:start position:0% +all expanded tail representations and +sensory and motor cortex + + align:start position:0% +sensory and motor cortex + + + align:start position:0% +sensory and motor cortex +okay + + align:start position:0% +okay + + + align:start position:0% +okay +for both the motor control of that tail + + align:start position:0% +for both the motor control of that tail + + + align:start position:0% +for both the motor control of that tail +and the sensory + + align:start position:0% +and the sensory + + + align:start position:0% +and the sensory +detection with the tail + + align:start position:0% +detection with the tail + + + align:start position:0% +detection with the tail +the glabrous specialized global skin + + align:start position:0% +the glabrous specialized global skin + + + align:start position:0% +the glabrous specialized global skin +like the skin of our + + align:start position:0% +like the skin of our + + + align:start position:0% +like the skin of our +fingers and palm than he has on his tail + + align:start position:0% +fingers and palm than he has on his tail + + + align:start position:0% +fingers and palm than he has on his tail +yes + + align:start position:0% + + + + align:start position:0% + +spider monkeys + + align:start position:0% +spider monkeys + + + align:start position:0% +spider monkeys +never seen a movie of spider monkey in + + align:start position:0% +never seen a movie of spider monkey in + + + align:start position:0% +never seen a movie of spider monkey in +the way they use their tail + + align:start position:0% + + + + align:start position:0% + +they use their tail like we use their + + align:start position:0% +they use their tail like we use their + + + align:start position:0% +they use their tail like we use their +hand + + align:start position:0% +hand + + + align:start position:0% +hand +when they go through the trees they're + + align:start position:0% +when they go through the trees they're + + + align:start position:0% +when they go through the trees they're +using their hands too + + align:start position:0% +using their hands too + + + align:start position:0% +using their hands too +using the tail and the hands okay + + align:start position:0% +using the tail and the hands okay + + + align:start position:0% +using the tail and the hands okay +and + + align:start position:0% +and + + + align:start position:0% +and +they can when they touch things with the + + align:start position:0% +they can when they touch things with the + + + align:start position:0% +they can when they touch things with the +tail they can be it's like we touching + + align:start position:0% +tail they can be it's like we touching + + + align:start position:0% +tail they can be it's like we touching +with our hands they can they have good + + align:start position:0% +with our hands they can they have good + + + align:start position:0% +with our hands they can they have good +acuity + + align:start position:0% + + + + align:start position:0% + +and i just want to point out here that + + align:start position:0% +and i just want to point out here that + + + align:start position:0% +and i just want to point out here that +in humans + + align:start position:0% +in humans + + + align:start position:0% +in humans +language is a specialization and that's + + align:start position:0% +language is a specialization and that's + + + align:start position:0% +language is a specialization and that's +led to expansions also or it's + + align:start position:0% +led to expansions also or it's + + + align:start position:0% +led to expansions also or it's +correlated with expansions + + align:start position:0% +correlated with expansions + + + align:start position:0% +correlated with expansions +of the polymodel association cortex the + + align:start position:0% +of the polymodel association cortex the + + + align:start position:0% +of the polymodel association cortex the +parietal temporal and frontal lobes it's + + align:start position:0% +parietal temporal and frontal lobes it's + + + align:start position:0% +parietal temporal and frontal lobes it's +also led to hemispheric specialization + + align:start position:0% + + + + align:start position:0% + +there may be other reasons though that + + align:start position:0% +there may be other reasons though that + + + align:start position:0% +there may be other reasons though that +lead to hemispheric specialization okay + + align:start position:0% +lead to hemispheric specialization okay + + + align:start position:0% +lead to hemispheric specialization okay +and finally + + align:start position:0% +and finally + + + align:start position:0% +and finally +i don't know if you'll hear about this + + align:start position:0% +i don't know if you'll hear about this + + + align:start position:0% +i don't know if you'll hear about this +in other classes but + + align:start position:0% +in other classes but + + + align:start position:0% +in other classes but +the elaborate social organization and + + align:start position:0% +the elaborate social organization and + + + align:start position:0% +the elaborate social organization and +planning and problem solving that you + + align:start position:0% +planning and problem solving that you + + + align:start position:0% +planning and problem solving that you +have in social animals social mammals + + align:start position:0% +have in social animals social mammals + + + align:start position:0% +have in social animals social mammals +okay + + align:start position:0% + + + + align:start position:0% + +that has a representation in the brain + + align:start position:0% +that has a representation in the brain + + + align:start position:0% +that has a representation in the brain +two especially + + align:start position:0% +two especially + + + align:start position:0% +two especially +prefrontal neocortical areas in the + + align:start position:0% +prefrontal neocortical areas in the + + + align:start position:0% +prefrontal neocortical areas in the +primates okay + + align:start position:0% +primates okay + + + align:start position:0% +primates okay +is huge in us + + align:start position:0% +is huge in us + + + align:start position:0% +is huge in us +okay + + align:start position:0% + + + + align:start position:0% + +and a lot of it has to do with + + align:start position:0% + + + + align:start position:0% + +planning and + + align:start position:0% +planning and + + + align:start position:0% +planning and +problem solving + + align:start position:0% +problem solving + + + align:start position:0% +problem solving +anticipating what we're going to do + + align:start position:0% +anticipating what we're going to do + + + align:start position:0% +anticipating what we're going to do +okay + + align:start position:0% + + + + align:start position:0% + +because females are so good at that i + + align:start position:0% +because females are so good at that i + + + align:start position:0% +because females are so good at that i +would probably say the female brain + + align:start position:0% +would probably say the female brain + + + align:start position:0% +would probably say the female brain +expanded first and the male had to catch + + align:start position:0% +expanded first and the male had to catch + + + align:start position:0% +expanded first and the male had to catch +up + + align:start position:0% +up + + + align:start position:0% +up +okay okay sorry but there are more women + + align:start position:0% +okay okay sorry but there are more women + + + align:start position:0% +okay okay sorry but there are more women +in this class i've got to say a few + + align:start position:0% +in this class i've got to say a few + + + align:start position:0% +in this class i've got to say a few +things like that it's probably true okay + + align:start position:0% +things like that it's probably true okay + + + align:start position:0% +things like that it's probably true okay +there is actually a theory of brain + + align:start position:0% +there is actually a theory of brain + + + align:start position:0% +there is actually a theory of brain +evolution that + + align:start position:0% +evolution that + + + align:start position:0% +evolution that +takes that view + + align:start position:0% +takes that view + + + align:start position:0% +takes that view +okay let's now start talking about going + + align:start position:0% +okay let's now start talking about going + + + align:start position:0% +okay let's now start talking about going +back to brain connections okay + + align:start position:0% +back to brain connections okay + + + align:start position:0% +back to brain connections okay +let's talk about basic subdivisions of + + align:start position:0% +let's talk about basic subdivisions of + + + align:start position:0% +let's talk about basic subdivisions of +the brain basic types of neurons we + + align:start position:0% +the brain basic types of neurons we + + + align:start position:0% +the brain basic types of neurons we +introduced that before + + align:start position:0% +introduced that before + + + align:start position:0% +introduced that before +okay + + align:start position:0% +okay + + + align:start position:0% +okay +basic channels of conduction of sensory + + align:start position:0% +basic channels of conduction of sensory + + + align:start position:0% +basic channels of conduction of sensory +information + + align:start position:0% +information + + + align:start position:0% +information +through and into the brain + + align:start position:0% +through and into the brain + + + align:start position:0% +through and into the brain +and then i'll give you an overview of + + align:start position:0% +and then i'll give you an overview of + + + align:start position:0% +and then i'll give you an overview of +the cephalic structures + + align:start position:0% +the cephalic structures + + + align:start position:0% +the cephalic structures +and finally we'll talk about the + + align:start position:0% +and finally we'll talk about the + + + align:start position:0% +and finally we'll talk about the +specialized + + align:start position:0% + + + + align:start position:0% + +connections that evolve with + + align:start position:0% +connections that evolve with + + + align:start position:0% +connections that evolve with +the elaboration of neocortex + + align:start position:0% +the elaboration of neocortex + + + align:start position:0% +the elaboration of neocortex +in the mammals + + align:start position:0% + + + + align:start position:0% + +i'm going to use + + align:start position:0% +i'm going to use + + + align:start position:0% +i'm going to use +the shmo brain for this + + align:start position:0% +the shmo brain for this + + + align:start position:0% +the shmo brain for this +so i'll have to tell you what a schmoo + + align:start position:0% +so i'll have to tell you what a schmoo + + + align:start position:0% +so i'll have to tell you what a schmoo +is + + align:start position:0% +is + + + align:start position:0% +is +and then we'll identify the basic + + align:start position:0% +and then we'll identify the basic + + + align:start position:0% +and then we'll identify the basic +structures and learn that some + + align:start position:0% +structures and learn that some + + + align:start position:0% +structures and learn that some +definitions + + align:start position:0% +definitions + + + align:start position:0% +definitions +here's a shmuel here the corner + + align:start position:0% +here's a shmuel here the corner + + + align:start position:0% +here's a shmuel here the corner +i got this he's very cute + + align:start position:0% +i got this he's very cute + + + align:start position:0% +i got this he's very cute +little animal + + align:start position:0% + + + + align:start position:0% + +he evolved in the brain of + + align:start position:0% +he evolved in the brain of + + + align:start position:0% +he evolved in the brain of +al cap was a cartoonist + + align:start position:0% +al cap was a cartoonist + + + align:start position:0% +al cap was a cartoonist +in chicago + + align:start position:0% + + + + align:start position:0% + +and this describes + + align:start position:0% + + + + align:start position:0% + +people used to read this every every + + align:start position:0% +people used to read this every every + + + align:start position:0% +people used to read this every every +time he published a + + align:start position:0% +time he published a + + + align:start position:0% +time he published a +little cartoon series in the chicago + + align:start position:0% +little cartoon series in the chicago + + + align:start position:0% +little cartoon series in the chicago +newspapers + + align:start position:0% + + + + align:start position:0% + +and it's just to remind you a little bit + + align:start position:0% +and it's just to remind you a little bit + + + align:start position:0% +and it's just to remind you a little bit +about shmuel because he loves all cars 9 + + align:start position:0% +about shmuel because he loves all cars 9 + + + align:start position:0% +about shmuel because he loves all cars 9 +students + + align:start position:0% +students + + + align:start position:0% +students +instinctively and without fail no matter + + align:start position:0% +instinctively and without fail no matter + + + align:start position:0% +instinctively and without fail no matter +what well you can read these + + align:start position:0% + + + + align:start position:0% + +you're also serious gosh + + align:start position:0% + + + + align:start position:0% + +well the schmooze is sort of serious too + + align:start position:0% +well the schmooze is sort of serious too + + + align:start position:0% +well the schmooze is sort of serious too +but he also makes you laugh + + align:start position:0% +but he also makes you laugh + + + align:start position:0% +but he also makes you laugh +okay + + align:start position:0% + + + + align:start position:0% + +so what is it it's a pedagogical device + + align:start position:0% +so what is it it's a pedagogical device + + + align:start position:0% +so what is it it's a pedagogical device +of course it was invented by nauta + + align:start position:0% +of course it was invented by nauta + + + align:start position:0% +of course it was invented by nauta +the great neuroanatomist who finished + + align:start position:0% +the great neuroanatomist who finished + + + align:start position:0% +the great neuroanatomist who finished +his career here at mit + + align:start position:0% +his career here at mit + + + align:start position:0% +his career here at mit +he invented it to illustrate some basic + + align:start position:0% +he invented it to illustrate some basic + + + align:start position:0% +he invented it to illustrate some basic +principles + + align:start position:0% +principles + + + align:start position:0% +principles +of the anatomical organization of the + + align:start position:0% +of the anatomical organization of the + + + align:start position:0% +of the anatomical organization of the +brain of animals + + align:start position:0% +brain of animals + + + align:start position:0% +brain of animals +suggested to be ancestral to mammals + + align:start position:0% +suggested to be ancestral to mammals + + + align:start position:0% +suggested to be ancestral to mammals +the first move could represent a + + align:start position:0% +the first move could represent a + + + align:start position:0% +the first move could represent a +generalized amphibian brain he usually + + align:start position:0% +generalized amphibian brain he usually + + + align:start position:0% +generalized amphibian brain he usually +described it that way it was based on + + align:start position:0% +described it that way it was based on + + + align:start position:0% +described it that way it was based on +the work of c judson herrick + + align:start position:0% +the work of c judson herrick + + + align:start position:0% +the work of c judson herrick +okay an american comparative anatomist + + align:start position:0% +okay an american comparative anatomist + + + align:start position:0% +okay an american comparative anatomist +and then more recent anatomical studies + + align:start position:0% +and then more recent anatomical studies + + + align:start position:0% +and then more recent anatomical studies +as well + + align:start position:0% +as well + + + align:start position:0% +as well +studies of connections that herrick did + + align:start position:0% +studies of connections that herrick did + + + align:start position:0% +studies of connections that herrick did +not know so well because he didn't use + + align:start position:0% +not know so well because he didn't use + + + align:start position:0% +not know so well because he didn't use +experimental studies to study + + align:start position:0% +experimental studies to study + + + align:start position:0% +experimental studies to study +connections the way nada and his + + align:start position:0% +connections the way nada and his + + + align:start position:0% +connections the way nada and his +students did + + align:start position:0% + + + + align:start position:0% + +now why do we study primitive why do i + + align:start position:0% +now why do we study primitive why do i + + + align:start position:0% +now why do we study primitive why do i +introduce the brain by talking about + + align:start position:0% +introduce the brain by talking about + + + align:start position:0% +introduce the brain by talking about +primitive brains why don't i just + + align:start position:0% +primitive brains why don't i just + + + align:start position:0% +primitive brains why don't i just +save time and go right to the human + + align:start position:0% +save time and go right to the human + + + align:start position:0% +save time and go right to the human +brain like they do in medical school + + align:start position:0% +brain like they do in medical school + + + align:start position:0% +brain like they do in medical school +okay + + align:start position:0% +okay + + + align:start position:0% +okay +well you'll find that you'll appreciate + + align:start position:0% +well you'll find that you'll appreciate + + + align:start position:0% +well you'll find that you'll appreciate +more and more + + align:start position:0% +more and more + + + align:start position:0% +more and more +why i do that as we go on + + align:start position:0% +why i do that as we go on + + + align:start position:0% +why i do that as we go on +but it's also relevant because + + align:start position:0% +but it's also relevant because + + + align:start position:0% +but it's also relevant because +not only helps you learn but it's we + + align:start position:0% +not only helps you learn but it's we + + + align:start position:0% +not only helps you learn but it's we +still have all those + + align:start position:0% +still have all those + + + align:start position:0% +still have all those +parts + + align:start position:0% +parts + + + align:start position:0% +parts +because when the brain evolved we don't + + align:start position:0% +because when the brain evolved we don't + + + align:start position:0% +because when the brain evolved we don't +just throw things out and replace it + + align:start position:0% +just throw things out and replace it + + + align:start position:0% +just throw things out and replace it +with something new we just add + + align:start position:0% +with something new we just add + + + align:start position:0% +with something new we just add +to what we had before + + align:start position:0% +to what we had before + + + align:start position:0% +to what we had before +okay + + align:start position:0% +okay + + + align:start position:0% +okay +very little is discarded i mean there + + align:start position:0% +very little is discarded i mean there + + + align:start position:0% +very little is discarded i mean there +are some things that get harnessed + + align:start position:0% +are some things that get harnessed + + + align:start position:0% +are some things that get harnessed +that might get smaller + + align:start position:0% +that might get smaller + + + align:start position:0% +that might get smaller +but basically we keep everything so you + + align:start position:0% +but basically we keep everything so you + + + align:start position:0% +but basically we keep everything so you +still have that + + align:start position:0% +still have that + + + align:start position:0% +still have that +ancestral brain the core of your human + + align:start position:0% +ancestral brain the core of your human + + + align:start position:0% +ancestral brain the core of your human +brain + + align:start position:0% +brain + + + align:start position:0% +brain +okay + + align:start position:0% + + + + align:start position:0% + +that little note you see + + align:start position:0% + + + + align:start position:0% + +crawling in the slime of the swamp or + + align:start position:0% +crawling in the slime of the swamp or + + + align:start position:0% +crawling in the slime of the swamp or +you might find in your basement + + align:start position:0% +you might find in your basement + + + align:start position:0% +you might find in your basement +has connections in his brain that you + + align:start position:0% +has connections in his brain that you + + + align:start position:0% +has connections in his brain that you +also have in yours + + align:start position:0% + + + + align:start position:0% + +and when we get very angry we probably + + align:start position:0% +and when we get very angry we probably + + + align:start position:0% +and when we get very angry we probably +use those a lot more + + align:start position:0% +use those a lot more + + + align:start position:0% +use those a lot more +okay let's + + align:start position:0% +okay let's + + + align:start position:0% +okay let's +first give you the outline here this is + + align:start position:0% +first give you the outline here this is + + + align:start position:0% +first give you the outline here this is +my outline of shmu1 + + align:start position:0% +my outline of shmu1 + + + align:start position:0% +my outline of shmu1 +and here are the subdivisions i want you + + align:start position:0% +and here are the subdivisions i want you + + + align:start position:0% +and here are the subdivisions i want you +to know all of these + + align:start position:0% +to know all of these + + + align:start position:0% +to know all of these +they're very basic you know some of them + + align:start position:0% +they're very basic you know some of them + + + align:start position:0% +they're very basic you know some of them +already it shows the spinal cord here at + + align:start position:0% +already it shows the spinal cord here at + + + align:start position:0% +already it shows the spinal cord here at +the caudal end + + align:start position:0% + + + + align:start position:0% + +here you see at the rostral in the + + align:start position:0% +here you see at the rostral in the + + + align:start position:0% +here you see at the rostral in the +olfactory bulb + + align:start position:0% + + + + align:start position:0% + +here's the midbrain + + align:start position:0% +here's the midbrain + + + align:start position:0% +here's the midbrain +sorry the hindbrain in the midbrain in + + align:start position:0% +sorry the hindbrain in the midbrain in + + + align:start position:0% +sorry the hindbrain in the midbrain in +the hindbrain i've shown the cerebellum + + align:start position:0% + + + + align:start position:0% + +in the brain brain the little bumps + + align:start position:0% +in the brain brain the little bumps + + + align:start position:0% +in the brain brain the little bumps +there represent the tectum of the + + align:start position:0% +there represent the tectum of the + + + align:start position:0% +there represent the tectum of the +midbrain + + align:start position:0% +midbrain + + + align:start position:0% +midbrain +the more anterior one is often called + + align:start position:0% +the more anterior one is often called + + + align:start position:0% +the more anterior one is often called +the optic tectum that's where those + + align:start position:0% +the optic tectum that's where those + + + align:start position:0% +the optic tectum that's where those +visual connections go and this is all + + align:start position:0% +visual connections go and this is all + + + align:start position:0% +visual connections go and this is all +forebrain + + align:start position:0% +forebrain + + + align:start position:0% +forebrain +and i've got it divided into different + + align:start position:0% +and i've got it divided into different + + + align:start position:0% +and i've got it divided into different +parts here + + align:start position:0% +parts here + + + align:start position:0% +parts here +the lower part here's the more caudal + + align:start position:0% +the lower part here's the more caudal + + + align:start position:0% +the lower part here's the more caudal +parts between brain and i've got the two + + align:start position:0% +parts between brain and i've got the two + + + align:start position:0% +parts between brain and i've got the two +major divisions here thalamus and + + align:start position:0% +major divisions here thalamus and + + + align:start position:0% +major divisions here thalamus and +hypothalamus there are a couple other + + align:start position:0% +hypothalamus there are a couple other + + + align:start position:0% +hypothalamus there are a couple other +divisions too + + align:start position:0% +divisions too + + + align:start position:0% +divisions too +okay + + align:start position:0% + + + + align:start position:0% + +but we know most about the two largest + + align:start position:0% +but we know most about the two largest + + + align:start position:0% +but we know most about the two largest +parts the thalamus and the hypothalamus + + align:start position:0% + + + + align:start position:0% + +and then the end brain + + align:start position:0% +and then the end brain + + + align:start position:0% +and then the end brain +corpus triadum subcortical structure + + align:start position:0% +corpus triadum subcortical structure + + + align:start position:0% +corpus triadum subcortical structure +other subcortical + + align:start position:0% +other subcortical + + + align:start position:0% +other subcortical +parts of the + + align:start position:0% +parts of the + + + align:start position:0% +parts of the +connected with that we call limbic + + align:start position:0% +connected with that we call limbic + + + align:start position:0% +connected with that we call limbic +because they're connected to the + + align:start position:0% +because they're connected to the + + + align:start position:0% +because they're connected to the +hypothalamus they're sort of at the + + align:start position:0% +hypothalamus they're sort of at the + + + align:start position:0% +hypothalamus they're sort of at the +fringes of the hemispheres + + align:start position:0% +fringes of the hemispheres + + + align:start position:0% +fringes of the hemispheres +and then + + align:start position:0% + + + + align:start position:0% + +cortical structures + + align:start position:0% +cortical structures + + + align:start position:0% +cortical structures +related to olfaction + + align:start position:0% +related to olfaction + + + align:start position:0% +related to olfaction +and + + align:start position:0% +and + + + align:start position:0% +and +what we call limbic cortex + + align:start position:0% +what we call limbic cortex + + + align:start position:0% +what we call limbic cortex +some of that + + align:start position:0% +some of that + + + align:start position:0% +some of that +that cortex that is not just olfactory + + align:start position:0% +that cortex that is not just olfactory + + + align:start position:0% +that cortex that is not just olfactory +but connected to hypothalamus + + align:start position:0% +but connected to hypothalamus + + + align:start position:0% +but connected to hypothalamus +there's no neocortex in schmuwan okay + + align:start position:0% +there's no neocortex in schmuwan okay + + + align:start position:0% +there's no neocortex in schmuwan okay +now in the most primitive amphibians + + align:start position:0% +now in the most primitive amphibians + + + align:start position:0% +now in the most primitive amphibians +that this is based on + + align:start position:0% +that this is based on + + + align:start position:0% +that this is based on +there is very little anything that looks + + align:start position:0% +there is very little anything that looks + + + align:start position:0% +there is very little anything that looks +like neocortex + + align:start position:0% +like neocortex + + + align:start position:0% +like neocortex +there's a little bit of cortex they call + + align:start position:0% +there's a little bit of cortex they call + + + align:start position:0% +there's a little bit of cortex they call +general cortex that's probably the + + align:start position:0% +general cortex that's probably the + + + align:start position:0% +general cortex that's probably the +predecessor of it + + align:start position:0% +predecessor of it + + + align:start position:0% +predecessor of it +and here i've shown + + align:start position:0% +and here i've shown + + + align:start position:0% +and here i've shown +some of the basic connections + + align:start position:0% +some of the basic connections + + + align:start position:0% +some of the basic connections +looks like + + align:start position:0% +looks like + + + align:start position:0% +looks like +a mishmash to you at the moment + + align:start position:0% +a mishmash to you at the moment + + + align:start position:0% +a mishmash to you at the moment +but it won't as we + + align:start position:0% +but it won't as we + + + align:start position:0% +but it won't as we +proceed + + align:start position:0% + + + + align:start position:0% + +now here i'm showing you what + + align:start position:0% +now here i'm showing you what + + + align:start position:0% +now here i'm showing you what +the actual neural tube + + align:start position:0% +the actual neural tube + + + align:start position:0% +the actual neural tube +looks like although i've exaggerated + + align:start position:0% +looks like although i've exaggerated + + + align:start position:0% +looks like although i've exaggerated +thickness of the + + align:start position:0% +thickness of the + + + align:start position:0% +thickness of the +spinal cord + + align:start position:0% +spinal cord + + + align:start position:0% +spinal cord +and brain stem a bit here + + align:start position:0% +and brain stem a bit here + + + align:start position:0% +and brain stem a bit here +remember it's a tube + + align:start position:0% +remember it's a tube + + + align:start position:0% +remember it's a tube +it's a tube that then expands more in + + align:start position:0% +it's a tube that then expands more in + + + align:start position:0% +it's a tube that then expands more in +some regions than others and on the + + align:start position:0% +some regions than others and on the + + + align:start position:0% +some regions than others and on the +right here i've shown the cross sections + + align:start position:0% +right here i've shown the cross sections + + + align:start position:0% +right here i've shown the cross sections +of these various levels there's a cross + + align:start position:0% +of these various levels there's a cross + + + align:start position:0% +of these various levels there's a cross +section through the + + align:start position:0% +section through the + + + align:start position:0% +section through the +the embryonic spinal cord + + align:start position:0% +the embryonic spinal cord + + + align:start position:0% +the embryonic spinal cord +and the embryonic hindbrain the + + align:start position:0% +and the embryonic hindbrain the + + + align:start position:0% +and the embryonic hindbrain the +embryonic midbrain + + align:start position:0% +embryonic midbrain + + + align:start position:0% +embryonic midbrain +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and then + + align:start position:0% +and then + + + align:start position:0% +and then +you see the twin brain and brain here + + align:start position:0% +you see the twin brain and brain here + + + align:start position:0% +you see the twin brain and brain here +the tween brain has this heart shape in + + align:start position:0% +the tween brain has this heart shape in + + + align:start position:0% +the tween brain has this heart shape in +its cross section + + align:start position:0% +its cross section + + + align:start position:0% +its cross section +and then the + + align:start position:0% +and then the + + + align:start position:0% +and then the +membrane with a corpus triadon below the + + align:start position:0% +membrane with a corpus triadon below the + + + align:start position:0% +membrane with a corpus triadon below the +ventricle + + align:start position:0% +ventricle + + + align:start position:0% +ventricle +and the cortex above okay + + align:start position:0% +and the cortex above okay + + + align:start position:0% +and the cortex above okay +and i'm showing here + + align:start position:0% +and i'm showing here + + + align:start position:0% +and i'm showing here +again the basic subdivisions which i + + align:start position:0% +again the basic subdivisions which i + + + align:start position:0% +again the basic subdivisions which i +would like you to learn there and i've + + align:start position:0% +would like you to learn there and i've + + + align:start position:0% +would like you to learn there and i've +given you the both the english + + align:start position:0% +given you the both the english + + + align:start position:0% +given you the both the english +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and the greek names + + align:start position:0% + + + + align:start position:0% + +so we'll keep repeating these i'll + + align:start position:0% +so we'll keep repeating these i'll + + + align:start position:0% +so we'll keep repeating these i'll +mention this i don't expect you to like + + align:start position:0% +mention this i don't expect you to like + + + align:start position:0% +mention this i don't expect you to like +to learn it instantly + + align:start position:0% +to learn it instantly + + + align:start position:0% +to learn it instantly +and i will repeat this a number of times + + align:start position:0% +and i will repeat this a number of times + + + align:start position:0% +and i will repeat this a number of times +to try to get you to relax a little bit + + align:start position:0% +to try to get you to relax a little bit + + + align:start position:0% +to try to get you to relax a little bit +neuroanatomy takes a little time to + + align:start position:0% +neuroanatomy takes a little time to + + + align:start position:0% +neuroanatomy takes a little time to +acquire you have to get it repeatedly + + align:start position:0% +acquire you have to get it repeatedly + + + align:start position:0% +acquire you have to get it repeatedly +and so i will go over things repeatedly + + align:start position:0% +and so i will go over things repeatedly + + + align:start position:0% +and so i will go over things repeatedly +in the class you'll also do some + + align:start position:0% +in the class you'll also do some + + + align:start position:0% +in the class you'll also do some +readings + + align:start position:0% +readings + + + align:start position:0% +readings +uh + + align:start position:0% +uh + + + align:start position:0% +uh +don't get too frustrated with yourself + + align:start position:0% +don't get too frustrated with yourself + + + align:start position:0% +don't get too frustrated with yourself +when you have trouble remembering it + + align:start position:0% +when you have trouble remembering it + + + align:start position:0% +when you have trouble remembering it +because it's like you can connect it + + align:start position:0% +because it's like you can connect it + + + align:start position:0% +because it's like you can connect it +with if it takes on more meaning to you + + align:start position:0% +with if it takes on more meaning to you + + + align:start position:0% +with if it takes on more meaning to you +when you know a little bit more about + + align:start position:0% +when you know a little bit more about + + + align:start position:0% +when you know a little bit more about +connections about function + + align:start position:0% +connections about function + + + align:start position:0% +connections about function +and it'll grow on you + + align:start position:0% + + + + align:start position:0% + +okay then we'll look at where these + + align:start position:0% +okay then we'll look at where these + + + align:start position:0% +okay then we'll look at where these +things are in the brain let's talk a + + align:start position:0% +things are in the brain let's talk a + + + align:start position:0% +things are in the brain let's talk a +little bit about the primary sensory + + align:start position:0% +little bit about the primary sensory + + + align:start position:0% +little bit about the primary sensory +neurons in different animals + + align:start position:0% +neurons in different animals + + + align:start position:0% +neurons in different animals +this is a picture from ramonica hall + + align:start position:0% +this is a picture from ramonica hall + + + align:start position:0% +this is a picture from ramonica hall +showing primary sensory neurons + + align:start position:0% +showing primary sensory neurons + + + align:start position:0% +showing primary sensory neurons +that carry input from the body surface + + align:start position:0% +that carry input from the body surface + + + align:start position:0% +that carry input from the body surface +okay + + align:start position:0% +okay + + + align:start position:0% +okay +in various species here + + align:start position:0% +in various species here + + + align:start position:0% +in various species here +here he has a sensory cell in the + + align:start position:0% +here he has a sensory cell in the + + + align:start position:0% +here he has a sensory cell in the +earthworm that goes to a sensory + + align:start position:0% +earthworm that goes to a sensory + + + align:start position:0% +earthworm that goes to a sensory +ganglion in the earthworm and notice + + align:start position:0% +ganglion in the earthworm and notice + + + align:start position:0% +ganglion in the earthworm and notice +that the the primary sensory neuron is + + align:start position:0% +that the the primary sensory neuron is + + + align:start position:0% +that the the primary sensory neuron is +in + + align:start position:0% +in + + + align:start position:0% +in +the surface epithelium of the body + + align:start position:0% +the surface epithelium of the body + + + align:start position:0% +the surface epithelium of the body +surface okay + + align:start position:0% +surface okay + + + align:start position:0% +surface okay +this is the epithelium + + align:start position:0% + + + + align:start position:0% + +the derivative of the ectoderm the + + align:start position:0% +the derivative of the ectoderm the + + + align:start position:0% +the derivative of the ectoderm the +surface layer the embryo the entire + + align:start position:0% +surface layer the embryo the entire + + + align:start position:0% +surface layer the embryo the entire +nervous system in fact is the derivative + + align:start position:0% +nervous system in fact is the derivative + + + align:start position:0% +nervous system in fact is the derivative +of the ectoderm + + align:start position:0% + + + + align:start position:0% + +here he shows the sensory cell in the + + align:start position:0% +here he shows the sensory cell in the + + + align:start position:0% +here he shows the sensory cell in the +mollusk which is similar but + + align:start position:0% +mollusk which is similar but + + + align:start position:0% +mollusk which is similar but +the cell body now + + align:start position:0% +the cell body now + + + align:start position:0% +the cell body now +has moved deep to the surface + + align:start position:0% +has moved deep to the surface + + + align:start position:0% +has moved deep to the surface +but it's still connected with the + + align:start position:0% +but it's still connected with the + + + align:start position:0% +but it's still connected with the +surface + + align:start position:0% +surface + + + align:start position:0% +surface +okay so now it's become + + align:start position:0% +okay so now it's become + + + align:start position:0% +okay so now it's become +a bipolar neuron + + align:start position:0% + + + + align:start position:0% + +with the input side + + align:start position:0% +with the input side + + + align:start position:0% +with the input side +at the surface and then the output side + + align:start position:0% +at the surface and then the output side + + + align:start position:0% +at the surface and then the output side +here in the sensor in the ganglion or + + align:start position:0% +here in the sensor in the ganglion or + + + align:start position:0% +here in the sensor in the ganglion or +central nervous system + + align:start position:0% +central nervous system + + + align:start position:0% +central nervous system +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and then he gets to vertebrates here + + align:start position:0% +and then he gets to vertebrates here + + + align:start position:0% +and then he gets to vertebrates here +and he's showing a sensory cell that a + + align:start position:0% +and he's showing a sensory cell that a + + + align:start position:0% +and he's showing a sensory cell that a +lower fish here which is still a bipolar + + align:start position:0% +lower fish here which is still a bipolar + + + align:start position:0% +lower fish here which is still a bipolar +neuron + + align:start position:0% + + + + align:start position:0% + +receiving inputs from the surface + + align:start position:0% +receiving inputs from the surface + + + align:start position:0% +receiving inputs from the surface +carrying it into the central nervous + + align:start position:0% +carrying it into the central nervous + + + align:start position:0% +carrying it into the central nervous +system the neural tube now because now + + align:start position:0% +system the neural tube now because now + + + align:start position:0% +system the neural tube now because now +we're invertebrates + + align:start position:0% + + + + align:start position:0% + +we're all chordates + + align:start position:0% +we're all chordates + + + align:start position:0% +we're all chordates +okay and then finally + + align:start position:0% +okay and then finally + + + align:start position:0% +okay and then finally +in amphibians reptiles birds and mammals + + align:start position:0% +in amphibians reptiles birds and mammals + + + align:start position:0% +in amphibians reptiles birds and mammals +the sensory cells innervating the body + + align:start position:0% +the sensory cells innervating the body + + + align:start position:0% +the sensory cells innervating the body +surface are have this + + align:start position:0% +surface are have this + + + align:start position:0% +surface are have this +we call it a pseudo-unipolar shape okay + + align:start position:0% +we call it a pseudo-unipolar shape okay + + + align:start position:0% +we call it a pseudo-unipolar shape okay +with the cell body off to the side + + align:start position:0% +with the cell body off to the side + + + align:start position:0% +with the cell body off to the side +dendritic part of the cell is out here + + align:start position:0% +dendritic part of the cell is out here + + + align:start position:0% +dendritic part of the cell is out here +and then the axon + + align:start position:0% +and then the axon + + + align:start position:0% +and then the axon +goes into the central nervous system + + align:start position:0% +goes into the central nervous system + + + align:start position:0% +goes into the central nervous system +this way + + align:start position:0% +this way + + + align:start position:0% +this way +so these + + align:start position:0% + + + + align:start position:0% + +the outlines here show what we would + + align:start position:0% +the outlines here show what we would + + + align:start position:0% +the outlines here show what we would +call a peripheral + + align:start position:0% +call a peripheral + + + align:start position:0% +call a peripheral +ganglion + + align:start position:0% + + + + align:start position:0% + +collections of those kinds of cells + + align:start position:0% +collections of those kinds of cells + + + align:start position:0% +collections of those kinds of cells +okay so now let's go back + + align:start position:0% +okay so now let's go back + + + align:start position:0% +okay so now let's go back +to the shmu brain now where the primary + + align:start position:0% +to the shmu brain now where the primary + + + align:start position:0% +to the shmu brain now where the primary +sensory neurons i've shown + + align:start position:0% +sensory neurons i've shown + + + align:start position:0% +sensory neurons i've shown +just three of them here + + align:start position:0% +just three of them here + + + align:start position:0% +just three of them here +here is + + align:start position:0% +here is + + + align:start position:0% +here is +an example only one + + align:start position:0% +an example only one + + + align:start position:0% +an example only one +showing a cell that would be in the + + align:start position:0% +showing a cell that would be in the + + + align:start position:0% +showing a cell that would be in the +dorsal root ganglia + + align:start position:0% +dorsal root ganglia + + + align:start position:0% +dorsal root ganglia +in one of the dorsal root ganglia + + align:start position:0% +in one of the dorsal root ganglia + + + align:start position:0% +in one of the dorsal root ganglia +okay + + align:start position:0% +okay + + + align:start position:0% +okay +next to the spinal cord + + align:start position:0% +next to the spinal cord + + + align:start position:0% +next to the spinal cord +so it's through the unipolar in shape + + align:start position:0% +so it's through the unipolar in shape + + + align:start position:0% +so it's through the unipolar in shape +it has its + + align:start position:0% +it has its + + + align:start position:0% +it has its +dendritic endings out here in the skin + + align:start position:0% +dendritic endings out here in the skin + + + align:start position:0% +dendritic endings out here in the skin +the axon starts there + + align:start position:0% +the axon starts there + + + align:start position:0% +the axon starts there +goes into the central nervous system + + align:start position:0% +goes into the central nervous system + + + align:start position:0% +goes into the central nervous system +where it connects with secondary sensory + + align:start position:0% +where it connects with secondary sensory + + + align:start position:0% +where it connects with secondary sensory +neurons okay + + align:start position:0% +neurons okay + + + align:start position:0% +neurons okay +here's another one this would be + + align:start position:0% +here's another one this would be + + + align:start position:0% +here's another one this would be +in the auditory or vestibular system and + + align:start position:0% +in the auditory or vestibular system and + + + align:start position:0% +in the auditory or vestibular system and +noted that it knows note that it has a + + align:start position:0% +noted that it knows note that it has a + + + align:start position:0% +noted that it knows note that it has a +bipolar shape there are many fewer of + + align:start position:0% +bipolar shape there are many fewer of + + + align:start position:0% +bipolar shape there are many fewer of +these + + align:start position:0% +these + + + align:start position:0% +these +okay but the in the auditory system we + + align:start position:0% +okay but the in the auditory system we + + + align:start position:0% +okay but the in the auditory system we +have bipolar neurons + + align:start position:0% +have bipolar neurons + + + align:start position:0% +have bipolar neurons +the sensory endodendric and + + align:start position:0% +the sensory endodendric and + + + align:start position:0% +the sensory endodendric and +out in the cochlea + + align:start position:0% +out in the cochlea + + + align:start position:0% +out in the cochlea +or in the vestibular canals okay + + align:start position:0% +or in the vestibular canals okay + + + align:start position:0% +or in the vestibular canals okay +and then + + align:start position:0% +and then + + + align:start position:0% +and then +the action potential has to go by the + + align:start position:0% +the action potential has to go by the + + + align:start position:0% +the action potential has to go by the +cell body it sort of jumps over it + + align:start position:0% +cell body it sort of jumps over it + + + align:start position:0% +cell body it sort of jumps over it +and the axon then continues into the + + align:start position:0% +and the axon then continues into the + + + align:start position:0% +and the axon then continues into the +central nervous system where you have + + align:start position:0% +central nervous system where you have + + + align:start position:0% +central nervous system where you have +the cochlear nuclei and the vestibular + + align:start position:0% +the cochlear nuclei and the vestibular + + + align:start position:0% +the cochlear nuclei and the vestibular +nuclei the secondary sensory cells of + + align:start position:0% +nuclei the secondary sensory cells of + + + align:start position:0% +nuclei the secondary sensory cells of +that those systems + + align:start position:0% +that those systems + + + align:start position:0% +that those systems +and finally here i show + + align:start position:0% +and finally here i show + + + align:start position:0% +and finally here i show +another primary sensory neuron on the + + align:start position:0% +another primary sensory neuron on the + + + align:start position:0% +another primary sensory neuron on the +olfactory an olfactory neuron an example + + align:start position:0% +olfactory an olfactory neuron an example + + + align:start position:0% +olfactory an olfactory neuron an example +of one olfactory and a note + + align:start position:0% +of one olfactory and a note + + + align:start position:0% +of one olfactory and a note +is just like the sensor all the sensory + + align:start position:0% +is just like the sensor all the sensory + + + align:start position:0% +is just like the sensor all the sensory +cells in the worm okay + + align:start position:0% +cells in the worm okay + + + align:start position:0% +cells in the worm okay +the cell body is insert at the surface + + align:start position:0% +the cell body is insert at the surface + + + align:start position:0% +the cell body is insert at the surface +and the epithelial layer + + align:start position:0% +and the epithelial layer + + + align:start position:0% +and the epithelial layer +okay + + align:start position:0% +okay + + + align:start position:0% +okay +that's + + align:start position:0% +that's + + + align:start position:0% +that's +in the mucosal factory mucosal lining + + align:start position:0% +in the mucosal factory mucosal lining + + + align:start position:0% +in the mucosal factory mucosal lining +our nasal passages + + align:start position:0% +our nasal passages + + + align:start position:0% +our nasal passages +then it has a little dendritic part here + + align:start position:0% +then it has a little dendritic part here + + + align:start position:0% +then it has a little dendritic part here +in a + + align:start position:0% +in a + + + align:start position:0% +in a +in a mucus + + align:start position:0% + + + + align:start position:0% + +over these + + align:start position:0% +over these + + + align:start position:0% +over these +cells response to molecules dissolved in + + align:start position:0% +cells response to molecules dissolved in + + + align:start position:0% +cells response to molecules dissolved in +that + + align:start position:0% +that + + + align:start position:0% +that +substance + + align:start position:0% +substance + + + align:start position:0% +substance +those molecules that trigger action + + align:start position:0% +those molecules that trigger action + + + align:start position:0% +those molecules that trigger action +potentials will the action potential + + align:start position:0% +potentials will the action potential + + + align:start position:0% +potentials will the action potential +goes + + align:start position:0% +goes + + + align:start position:0% +goes +through the primary olfactory neurons + + align:start position:0% +through the primary olfactory neurons + + + align:start position:0% +through the primary olfactory neurons +axon into the brain part of the brain + + align:start position:0% +axon into the brain part of the brain + + + align:start position:0% +axon into the brain part of the brain +here we call the olfactory bulb where it + + align:start position:0% +here we call the olfactory bulb where it + + + align:start position:0% +here we call the olfactory bulb where it +contacts secondary sensory cells of the + + align:start position:0% +contacts secondary sensory cells of the + + + align:start position:0% +contacts secondary sensory cells of the +olfactory system okay so three examples + + align:start position:0% +olfactory system okay so three examples + + + align:start position:0% +olfactory system okay so three examples +of primary sensory neurons + + align:start position:0% +of primary sensory neurons + + + align:start position:0% +of primary sensory neurons +the secondary sensory neurons are the + + align:start position:0% +the secondary sensory neurons are the + + + align:start position:0% +the secondary sensory neurons are the +ones that get input to it + + align:start position:0% +ones that get input to it + + + align:start position:0% +ones that get input to it +everything else is an interneuron + + align:start position:0% +everything else is an interneuron + + + align:start position:0% +everything else is an interneuron +and of course we want to understand how + + align:start position:0% +and of course we want to understand how + + + align:start position:0% +and of course we want to understand how +are those interneurons connected what + + align:start position:0% +are those interneurons connected what + + + align:start position:0% +are those interneurons connected what +kind of systems do they form + + align:start position:0% +kind of systems do they form + + + align:start position:0% +kind of systems do they form +the only exception that we don't call + + align:start position:0% +the only exception that we don't call + + + align:start position:0% +the only exception that we don't call +interneuron here is the motor neuron and + + align:start position:0% +interneuron here is the motor neuron and + + + align:start position:0% +interneuron here is the motor neuron and +i'm showing it here in the little black + + align:start position:0% +i'm showing it here in the little black + + + align:start position:0% +i'm showing it here in the little black +triangles + + align:start position:0% +triangles + + + align:start position:0% +triangles +that you see in the + + align:start position:0% +that you see in the + + + align:start position:0% +that you see in the +ventral part + + align:start position:0% +ventral part + + + align:start position:0% +ventral part +of the brain in the spinal cord + + align:start position:0% +of the brain in the spinal cord + + + align:start position:0% +of the brain in the spinal cord +but also + + align:start position:0% +but also + + + align:start position:0% +but also +in the + + align:start position:0% +in the + + + align:start position:0% +in the +hind brain and in the midbrain + + align:start position:0% +hind brain and in the midbrain + + + align:start position:0% +hind brain and in the midbrain +okay + + align:start position:0% +okay + + + align:start position:0% +okay +where there are collections of these + + align:start position:0% +where there are collections of these + + + align:start position:0% +where there are collections of these +motor neurons motor neurons are defined + + align:start position:0% +motor neurons motor neurons are defined + + + align:start position:0% +motor neurons motor neurons are defined +as the neurons with an axon that goes + + align:start position:0% +as the neurons with an axon that goes + + + align:start position:0% +as the neurons with an axon that goes +out of the central nervous system + + align:start position:0% +out of the central nervous system + + + align:start position:0% +out of the central nervous system +okay and we have two kinds + + align:start position:0% +okay and we have two kinds + + + align:start position:0% +okay and we have two kinds +of motor neurons there and i've shown + + align:start position:0% +of motor neurons there and i've shown + + + align:start position:0% +of motor neurons there and i've shown +the two kinds + + align:start position:0% +the two kinds + + + align:start position:0% +the two kinds +here one type the axon goes to muscle + + align:start position:0% +here one type the axon goes to muscle + + + align:start position:0% +here one type the axon goes to muscle +cells + + align:start position:0% +cells + + + align:start position:0% +cells +just striated muscle cells i've shown + + align:start position:0% +just striated muscle cells i've shown + + + align:start position:0% +just striated muscle cells i've shown +depicted the striations there to + + align:start position:0% +depicted the striations there to + + + align:start position:0% +depicted the striations there to +indicate a particular kind of muscle + + align:start position:0% +indicate a particular kind of muscle + + + align:start position:0% +indicate a particular kind of muscle +cell it's not a smooth muscle + + align:start position:0% +cell it's not a smooth muscle + + + align:start position:0% +cell it's not a smooth muscle +the other kind of motor neuron connects + + align:start position:0% +the other kind of motor neuron connects + + + align:start position:0% +the other kind of motor neuron connects +with a ganglion + + align:start position:0% +with a ganglion + + + align:start position:0% +with a ganglion +so we call it a preganglionic motor + + align:start position:0% +so we call it a preganglionic motor + + + align:start position:0% +so we call it a preganglionic motor +neuron + + align:start position:0% +neuron + + + align:start position:0% +neuron +of the autonomic nervous system the + + align:start position:0% +of the autonomic nervous system the + + + align:start position:0% +of the autonomic nervous system the +autonomic nervous system innervates + + align:start position:0% +autonomic nervous system innervates + + + align:start position:0% +autonomic nervous system innervates +smooth muscles and glands + + align:start position:0% +smooth muscles and glands + + + align:start position:0% +smooth muscles and glands +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so there the connection is different it + + align:start position:0% +so there the connection is different it + + + align:start position:0% +so there the connection is different it +goes through a relay in a peripheral + + align:start position:0% +goes through a relay in a peripheral + + + align:start position:0% +goes through a relay in a peripheral +ganglion + + align:start position:0% +ganglion + + + align:start position:0% +ganglion +of the autonomic nervous system + + align:start position:0% +of the autonomic nervous system + + + align:start position:0% +of the autonomic nervous system +and then those cells + + align:start position:0% +and then those cells + + + align:start position:0% +and then those cells +in those ganglia connect to smooth + + align:start position:0% +in those ganglia connect to smooth + + + align:start position:0% +in those ganglia connect to smooth +muscle and gland tissue + + align:start position:0% +muscle and gland tissue + + + align:start position:0% +muscle and gland tissue +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so two kinds of motor neurons + + align:start position:0% +so two kinds of motor neurons + + + align:start position:0% +so two kinds of motor neurons +[Applause] + + align:start position:0% + + + + align:start position:0% + +okay so we've defined now + + align:start position:0% +okay so we've defined now + + + align:start position:0% +okay so we've defined now +the subdivisions the primary sensory + + align:start position:0% +the subdivisions the primary sensory + + + align:start position:0% +the subdivisions the primary sensory +neurons secondary sensory neurons + + align:start position:0% +neurons secondary sensory neurons + + + align:start position:0% +neurons secondary sensory neurons +interneurons of the great intermediate + + align:start position:0% +interneurons of the great intermediate + + + align:start position:0% +interneurons of the great intermediate +net + + align:start position:0% +net + + + align:start position:0% +net +two kinds of motor neurons + + align:start position:0% +two kinds of motor neurons + + + align:start position:0% +two kinds of motor neurons +cranial nerves + + align:start position:0% +cranial nerves + + + align:start position:0% +cranial nerves +one and eight + + align:start position:0% +one and eight + + + align:start position:0% +one and eight +well + + align:start position:0% + + + + align:start position:0% + +cranial nerve one you generally the + + align:start position:0% +cranial nerve one you generally the + + + align:start position:0% +cranial nerve one you generally the +cranial nerves are the nerves coming in + + align:start position:0% +cranial nerves are the nerves coming in + + + align:start position:0% +cranial nerves are the nerves coming in +the head + + align:start position:0% + + + + align:start position:0% + +sorry in the head that come into the + + align:start position:0% +sorry in the head that come into the + + + align:start position:0% +sorry in the head that come into the +brain above the spinal cord and they're + + align:start position:0% +brain above the spinal cord and they're + + + align:start position:0% +brain above the spinal cord and they're +numbered from rostral claddle + + align:start position:0% +numbered from rostral claddle + + + align:start position:0% +numbered from rostral claddle +okay + + align:start position:0% +okay + + + align:start position:0% +okay +there's + + align:start position:0% +there's + + + align:start position:0% +there's +quite a few of them well over 20 in fact + + align:start position:0% +quite a few of them well over 20 in fact + + + align:start position:0% +quite a few of them well over 20 in fact +but + + align:start position:0% +but + + + align:start position:0% +but +there's only 12 major ones in humans and + + align:start position:0% +there's only 12 major ones in humans and + + + align:start position:0% +there's only 12 major ones in humans and +so we usually think of just 12 cranial + + align:start position:0% +so we usually think of just 12 cranial + + + align:start position:0% +so we usually think of just 12 cranial +nerves + + align:start position:0% +nerves + + + align:start position:0% +nerves +the first one the rostral one is the + + align:start position:0% +the first one the rostral one is the + + + align:start position:0% +the first one the rostral one is the +olfactory + + align:start position:0% +olfactory + + + align:start position:0% +olfactory +the eighth one + + align:start position:0% +the eighth one + + + align:start position:0% +the eighth one +is the auditory distributor + + align:start position:0% +is the auditory distributor + + + align:start position:0% +is the auditory distributor +okay and those are the only ones i'm + + align:start position:0% +okay and those are the only ones i'm + + + align:start position:0% +okay and those are the only ones i'm +showing here + + align:start position:0% + + + + align:start position:0% + +which is why + + align:start position:0% +which is why + + + align:start position:0% +which is why +i put it here to be identified in the + + align:start position:0% +i put it here to be identified in the + + + align:start position:0% +i put it here to be identified in the +shrew brain here + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so now what happens to the input when it + + align:start position:0% +so now what happens to the input when it + + + align:start position:0% +so now what happens to the input when it +comes in and here we're going to focus + + align:start position:0% +comes in and here we're going to focus + + + align:start position:0% +comes in and here we're going to focus +on spinal cord initially + + align:start position:0% +on spinal cord initially + + + align:start position:0% +on spinal cord initially +but the other sensory systems have + + align:start position:0% +but the other sensory systems have + + + align:start position:0% +but the other sensory systems have +similar channels of conduction + + align:start position:0% +similar channels of conduction + + + align:start position:0% +similar channels of conduction +in every case we can talk about a local + + align:start position:0% +in every case we can talk about a local + + + align:start position:0% +in every case we can talk about a local +reflex channel + + align:start position:0% +reflex channel + + + align:start position:0% +reflex channel +cerebellar channel + + align:start position:0% +cerebellar channel + + + align:start position:0% +cerebellar channel +and leniscal channels plural okay + + align:start position:0% + + + + align:start position:0% + +and we're gonna + + align:start position:0% +and we're gonna + + + align:start position:0% +and we're gonna +learn all these terms + + align:start position:0% + + + + align:start position:0% + +we'll first talk about segmental + + align:start position:0% +we'll first talk about segmental + + + align:start position:0% +we'll first talk about segmental +reflexes + + align:start position:0% +reflexes + + + align:start position:0% +reflexes +okay + + align:start position:0% + + + + align:start position:0% + +and we'll define + + align:start position:0% +and we'll define + + + align:start position:0% +and we'll define +dermatome and myotone + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +here would be the we could call it also + + align:start position:0% +here would be the we could call it also + + + align:start position:0% +here would be the we could call it also +a local reflex channel we can follow + + align:start position:0% +a local reflex channel we can follow + + + align:start position:0% +a local reflex channel we can follow +input through a primary sensory neuron + + align:start position:0% +input through a primary sensory neuron + + + align:start position:0% +input through a primary sensory neuron +in the shmu brain here + + align:start position:0% +in the shmu brain here + + + align:start position:0% +in the shmu brain here +context secondary sensory cells and some + + align:start position:0% +context secondary sensory cells and some + + + align:start position:0% +context secondary sensory cells and some +of those have fairly short connections + + align:start position:0% +of those have fairly short connections + + + align:start position:0% +of those have fairly short connections +through interneurons reaching motor + + align:start position:0% +through interneurons reaching motor + + + align:start position:0% +through interneurons reaching motor +neurons + + align:start position:0% +neurons + + + align:start position:0% +neurons +now that all happens within one segment + + align:start position:0% +now that all happens within one segment + + + align:start position:0% +now that all happens within one segment +of the spinal cord the segment being + + align:start position:0% +of the spinal cord the segment being + + + align:start position:0% +of the spinal cord the segment being +defined + + align:start position:0% +defined + + + align:start position:0% +defined +as the area connected with one spinal + + align:start position:0% +as the area connected with one spinal + + + align:start position:0% +as the area connected with one spinal +nerve one dorsal root + + align:start position:0% +nerve one dorsal root + + + align:start position:0% +nerve one dorsal root +okay + + align:start position:0% + + + + align:start position:0% + +so there's about 32 segments in the + + align:start position:0% + + + + align:start position:0% + +cord and if that then goes from sensory + + align:start position:0% +cord and if that then goes from sensory + + + align:start position:0% +cord and if that then goes from sensory +to motor within one segment contacts the + + align:start position:0% +to motor within one segment contacts the + + + align:start position:0% +to motor within one segment contacts the +motor neuron we would call a segmental + + align:start position:0% +motor neuron we would call a segmental + + + align:start position:0% +motor neuron we would call a segmental +reflex + + align:start position:0% +reflex + + + align:start position:0% +reflex +okay or local reflex + + align:start position:0% + + + + align:start position:0% + +if it comes in at one segment here but + + align:start position:0% +if it comes in at one segment here but + + + align:start position:0% +if it comes in at one segment here but +the output through interneurons connects + + align:start position:0% +the output through interneurons connects + + + align:start position:0% +the output through interneurons connects +with other segments in the chord + + align:start position:0% +with other segments in the chord + + + align:start position:0% +with other segments in the chord +then we would call it an intersegmental + + align:start position:0% +then we would call it an intersegmental + + + align:start position:0% +then we would call it an intersegmental +reflex + + align:start position:0% + + + + align:start position:0% + +but if it involves these long axons + + align:start position:0% +but if it involves these long axons + + + align:start position:0% +but if it involves these long axons +going up into the brain the liministical + + align:start position:0% +going up into the brain the liministical + + + align:start position:0% +going up into the brain the liministical +channels + + align:start position:0% +channels + + + align:start position:0% +channels +before it comes back + + align:start position:0% +before it comes back + + + align:start position:0% +before it comes back +if we're going to call it still a reflex + + align:start position:0% +if we're going to call it still a reflex + + + align:start position:0% +if we're going to call it still a reflex +we would call it a suprasegmental reflex + + align:start position:0% +we would call it a suprasegmental reflex + + + align:start position:0% +we would call it a suprasegmental reflex +okay because it involves conduction + + align:start position:0% +okay because it involves conduction + + + align:start position:0% +okay because it involves conduction +above + + align:start position:0% +above + + + align:start position:0% +above +supra + + align:start position:0% +supra + + + align:start position:0% +supra +above the segments of the spinal cord + + align:start position:0% +above the segments of the spinal cord + + + align:start position:0% +above the segments of the spinal cord +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +okay now + + align:start position:0% +okay now + + + align:start position:0% +okay now +the + + align:start position:0% +the + + + align:start position:0% +the +if we're dealing with + + align:start position:0% +if we're dealing with + + + align:start position:0% +if we're dealing with +one dorsal root here + + align:start position:0% +one dorsal root here + + + align:start position:0% +one dorsal root here +which is a collection of axons of course + + align:start position:0% +which is a collection of axons of course + + + align:start position:0% +which is a collection of axons of course +coming through one spinal nerve + + align:start position:0% +coming through one spinal nerve + + + align:start position:0% +coming through one spinal nerve +those axons originate on the body + + align:start position:0% +those axons originate on the body + + + align:start position:0% +those axons originate on the body +surface + + align:start position:0% +surface + + + align:start position:0% +surface +from just a limited + + align:start position:0% +from just a limited + + + align:start position:0% +from just a limited +part of the skin and we call the skin + + align:start position:0% +part of the skin and we call the skin + + + align:start position:0% +part of the skin and we call the skin +innervated by one + + align:start position:0% +innervated by one + + + align:start position:0% +innervated by one +spinal nerve we call it a dermatome and + + align:start position:0% +spinal nerve we call it a dermatome and + + + align:start position:0% +spinal nerve we call it a dermatome and +this is a dermatomal map + + align:start position:0% +this is a dermatomal map + + + align:start position:0% +this is a dermatomal map +okay + + align:start position:0% + + + + align:start position:0% + +showing + + align:start position:0% +showing + + + align:start position:0% +showing +usually there's no + + align:start position:0% +usually there's no + + + align:start position:0% +usually there's no +first cervical segment + + align:start position:0% +first cervical segment + + + align:start position:0% +first cervical segment +dorsal root we start with c2 to c8 + + align:start position:0% +dorsal root we start with c2 to c8 + + + align:start position:0% +dorsal root we start with c2 to c8 +and then the thoracic segments t1 + + align:start position:0% +and then the thoracic segments t1 + + + align:start position:0% +and then the thoracic segments t1 +through 12 + + align:start position:0% +through 12 + + + align:start position:0% +through 12 +5 lumbar segments and five sacral + + align:start position:0% +5 lumbar segments and five sacral + + + align:start position:0% +5 lumbar segments and five sacral +segments okay + + align:start position:0% + + + + align:start position:0% + +usually because + + align:start position:0% +usually because + + + align:start position:0% +usually because +because the gel segments are not even + + align:start position:0% +because the gel segments are not even + + + align:start position:0% +because the gel segments are not even +indicated on these dermatol maps because + + align:start position:0% +indicated on these dermatol maps because + + + align:start position:0% +indicated on these dermatol maps because +they're not very large or important + + align:start position:0% +they're not very large or important + + + align:start position:0% +they're not very large or important +okay + + align:start position:0% + + + + align:start position:0% + +if we put the human in a quadruped + + align:start position:0% +if we put the human in a quadruped + + + align:start position:0% +if we put the human in a quadruped +position + + align:start position:0% +position + + + align:start position:0% +position +we can see + + align:start position:0% +we can see + + + align:start position:0% +we can see +why those dermatomes are the way they + + align:start position:0% +why those dermatomes are the way they + + + align:start position:0% +why those dermatomes are the way they +are because in early development of + + align:start position:0% +are because in early development of + + + align:start position:0% +are because in early development of +course the limbs are very short and + + align:start position:0% +course the limbs are very short and + + + align:start position:0% +course the limbs are very short and +stubby when these things first develop + + align:start position:0% + + + + align:start position:0% + +so the body is segmented the same way + + align:start position:0% +so the body is segmented the same way + + + align:start position:0% +so the body is segmented the same way +the spinal cord is segmented if we look + + align:start position:0% +the spinal cord is segmented if we look + + + align:start position:0% +the spinal cord is segmented if we look +at it this way okay now why + + align:start position:0% +at it this way okay now why + + + align:start position:0% +at it this way okay now why +do we start the map with the c2 + + align:start position:0% +do we start the map with the c2 + + + align:start position:0% +do we start the map with the c2 +innervation here + + align:start position:0% +innervation here + + + align:start position:0% +innervation here +in the middle of the head + + align:start position:0% + + + + align:start position:0% + +why + + align:start position:0% +why + + + align:start position:0% +why +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +everything else is cranial nerve that's + + align:start position:0% +everything else is cranial nerve that's + + + align:start position:0% +everything else is cranial nerve that's +right + + align:start position:0% +right + + + align:start position:0% +right +okay so the cranial nerves they'll + + align:start position:0% +okay so the cranial nerves they'll + + + align:start position:0% +okay so the cranial nerves they'll +innovate the face primarily the fifth + + align:start position:0% +innovate the face primarily the fifth + + + align:start position:0% +innovate the face primarily the fifth +cranial nerve + + align:start position:0% +cranial nerve + + + align:start position:0% +cranial nerve +okay + + align:start position:0% +okay + + + align:start position:0% +okay +although the cranial nerves too but the + + align:start position:0% +although the cranial nerves too but the + + + align:start position:0% +although the cranial nerves too but the +skin + + align:start position:0% +skin + + + align:start position:0% +skin +is the skin surface of the + + align:start position:0% +is the skin surface of the + + + align:start position:0% +is the skin surface of the +face their forehead and face is the + + align:start position:0% +face their forehead and face is the + + + align:start position:0% +face their forehead and face is the +fifth cranial nerve + + align:start position:0% +fifth cranial nerve + + + align:start position:0% +fifth cranial nerve +then we have the + + align:start position:0% +then we have the + + + align:start position:0% +then we have the +cervical segments okay + + align:start position:0% +cervical segments okay + + + align:start position:0% +cervical segments okay +then the thoracic + + align:start position:0% +then the thoracic + + + align:start position:0% +then the thoracic +the lumbar and the sacral + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +with this kind of map if you look at the + + align:start position:0% +with this kind of map if you look at the + + + align:start position:0% +with this kind of map if you look at the +dermatomes + + align:start position:0% +dermatomes + + + align:start position:0% +dermatomes +then we know that + + align:start position:0% + + + + align:start position:0% + +the caudal mouse part is right around + + align:start position:0% +the caudal mouse part is right around + + + align:start position:0% +the caudal mouse part is right around +the anus + + align:start position:0% + + + + align:start position:0% + +the very tail end okay + + align:start position:0% +the very tail end okay + + + align:start position:0% +the very tail end okay +and the reason for these + + align:start position:0% +and the reason for these + + + align:start position:0% +and the reason for these +funny ways divided up in the legs and + + align:start position:0% +funny ways divided up in the legs and + + + align:start position:0% +funny ways divided up in the legs and +arms + + align:start position:0% +arms + + + align:start position:0% +arms +is because of the way those nerves grew + + align:start position:0% +is because of the way those nerves grew + + + align:start position:0% +is because of the way those nerves grew +into in development okay but basically + + align:start position:0% +into in development okay but basically + + + align:start position:0% +into in development okay but basically +they follow the dermatomal pattern that + + align:start position:0% +they follow the dermatomal pattern that + + + align:start position:0% +they follow the dermatomal pattern that +you see here + + align:start position:0% + + + + align:start position:0% + +now the innovation of adjacent dorsal + + align:start position:0% +now the innovation of adjacent dorsal + + + align:start position:0% +now the innovation of adjacent dorsal +roots here and here they + + align:start position:0% +roots here and here they + + + align:start position:0% +roots here and here they +the + + align:start position:0% +the + + + align:start position:0% +the +cartoon here on the right they're + + align:start position:0% +cartoon here on the right they're + + + align:start position:0% +cartoon here on the right they're +showing + + align:start position:0% +showing + + + align:start position:0% +showing +they only show a single axon + + align:start position:0% +they only show a single axon + + + align:start position:0% +they only show a single axon +in each they're showing up a single + + align:start position:0% +in each they're showing up a single + + + align:start position:0% +in each they're showing up a single +peripheral nerve that may enter several + + align:start position:0% +peripheral nerve that may enter several + + + align:start position:0% +peripheral nerve that may enter several +spinal nerves so it goes in through + + align:start position:0% +spinal nerves so it goes in through + + + align:start position:0% +spinal nerves so it goes in through +several different dorsal roots + + align:start position:0% +several different dorsal roots + + + align:start position:0% +several different dorsal roots +that's what they're showing there + + align:start position:0% +that's what they're showing there + + + align:start position:0% +that's what they're showing there +and they show that + + align:start position:0% +and they show that + + + align:start position:0% +and they show that +out in the periphery it can come there + + align:start position:0% +out in the periphery it can come there + + + align:start position:0% +out in the periphery it can come there +are there is some overlap okay + + align:start position:0% + + + + align:start position:0% + +of the way these innervate but it's a + + align:start position:0% +of the way these innervate but it's a + + + align:start position:0% +of the way these innervate but it's a +limited amount of overlap now how do + + align:start position:0% +limited amount of overlap now how do + + + align:start position:0% +limited amount of overlap now how do +those things how were they mapped + + align:start position:0% +those things how were they mapped + + + align:start position:0% +those things how were they mapped +well there was two major methods + + align:start position:0% +well there was two major methods + + + align:start position:0% +well there was two major methods +first of all the regions that become + + align:start position:0% +first of all the regions that become + + + align:start position:0% +first of all the regions that become +hypersensitive when a single spinal root + + align:start position:0% +hypersensitive when a single spinal root + + + align:start position:0% +hypersensitive when a single spinal root +is irritated + + align:start position:0% +is irritated + + + align:start position:0% +is irritated +of course you could stimulate it + + align:start position:0% +of course you could stimulate it + + + align:start position:0% +of course you could stimulate it +electrically but we usually don't + + align:start position:0% +electrically but we usually don't + + + align:start position:0% +electrically but we usually don't +experiment like that with human beings + + align:start position:0% +experiment like that with human beings + + + align:start position:0% +experiment like that with human beings +but we don't have to because they have + + align:start position:0% +but we don't have to because they have + + + align:start position:0% +but we don't have to because they have +problems with backs like + + align:start position:0% +problems with backs like + + + align:start position:0% +problems with backs like +inevitable discs can + + align:start position:0% +inevitable discs can + + + align:start position:0% +inevitable discs can +slip and herniate and put pressure on a + + align:start position:0% +slip and herniate and put pressure on a + + + align:start position:0% +slip and herniate and put pressure on a +dorsal root + + align:start position:0% +dorsal root + + + align:start position:0% +dorsal root +they can even transect another dorsal + + align:start position:0% +they can even transect another dorsal + + + align:start position:0% +they can even transect another dorsal +root + + align:start position:0% +root + + + align:start position:0% +root +usually they cause initially just + + align:start position:0% +usually they cause initially just + + + align:start position:0% +usually they cause initially just +irritation + + align:start position:0% +irritation + + + align:start position:0% +irritation +and then we can map the area of the body + + align:start position:0% +and then we can map the area of the body + + + align:start position:0% +and then we can map the area of the body +that is + + align:start position:0% +that is + + + align:start position:0% +that is +shows the irritation + + align:start position:0% +shows the irritation + + + align:start position:0% +shows the irritation +the irritation of course results in + + align:start position:0% +the irritation of course results in + + + align:start position:0% +the irritation of course results in +action potential so it gives us feeling + + align:start position:0% +action potential so it gives us feeling + + + align:start position:0% +action potential so it gives us feeling +like it's coming from the skin like if + + align:start position:0% +like it's coming from the skin like if + + + align:start position:0% +like it's coming from the skin like if +we hit + + align:start position:0% +we hit + + + align:start position:0% +we hit +we hit a nerve which we you can hit a + + align:start position:0% +we hit a nerve which we you can hit a + + + align:start position:0% +we hit a nerve which we you can hit a +nerve in your elbow because it's very + + align:start position:0% +nerve in your elbow because it's very + + + align:start position:0% +nerve in your elbow because it's very +close to the surface there + + align:start position:0% +close to the surface there + + + align:start position:0% +close to the surface there +so that's why we call it the funny bone + + align:start position:0% +so that's why we call it the funny bone + + + align:start position:0% +so that's why we call it the funny bone +we can we can actually disturb it and + + align:start position:0% +we can we can actually disturb it and + + + align:start position:0% +we can we can actually disturb it and +fire action potentials there that would + + align:start position:0% +fire action potentials there that would + + + align:start position:0% +fire action potentials there that would +that's similar to + + align:start position:0% + + + + align:start position:0% + +to this method of mapping a dermatome so + + align:start position:0% +to this method of mapping a dermatome so + + + align:start position:0% +to this method of mapping a dermatome so +we can map the hypersensitive regions we + + align:start position:0% +we can map the hypersensitive regions we + + + align:start position:0% +we can map the hypersensitive regions we +can also look at + + align:start position:0% +can also look at + + + align:start position:0% +can also look at +what happens in the rare cases where + + align:start position:0% +what happens in the rare cases where + + + align:start position:0% +what happens in the rare cases where +there's a severance of adjacent spinal + + align:start position:0% +there's a severance of adjacent spinal + + + align:start position:0% +there's a severance of adjacent spinal +nerves if there's a one nerve remaining + + align:start position:0% +nerves if there's a one nerve remaining + + + align:start position:0% +nerves if there's a one nerve remaining +and sort of as an island we'll see an + + align:start position:0% +and sort of as an island we'll see an + + + align:start position:0% +and sort of as an island we'll see an +area of remaining sensibility + + align:start position:0% + + + + align:start position:0% + +so that's how these were mapped and + + align:start position:0% +so that's how these were mapped and + + + align:start position:0% +so that's how these were mapped and +sometimes we talk about a myotome also + + align:start position:0% +sometimes we talk about a myotome also + + + align:start position:0% +sometimes we talk about a myotome also +the corresponding muscles of the ventral + + align:start position:0% +the corresponding muscles of the ventral + + + align:start position:0% +the corresponding muscles of the ventral +root the same segment and there's a + + align:start position:0% +root the same segment and there's a + + + align:start position:0% +root the same segment and there's a +pretty good correspondence between the + + align:start position:0% +pretty good correspondence between the + + + align:start position:0% +pretty good correspondence between the +position of the dermatomes and myotones + + align:start position:0% + + + + align:start position:0% + +all right + + align:start position:0% +all right + + + align:start position:0% +all right +and + + align:start position:0% +and + + + align:start position:0% +and +i my timing was perfect today we're + + align:start position:0% +i my timing was perfect today we're + + + align:start position:0% +i my timing was perfect today we're +right at the end of the hour \ No newline at end of file diff --git a/MK3DduTjcrA.txt b/MK3DduTjcrA.txt new file mode 100644 index 0000000000000000000000000000000000000000..eef17a34a81e6b892bd93a542348f57ead25a5e6 --- /dev/null +++ b/MK3DduTjcrA.txt @@ -0,0 +1,99 @@ +To illustrate how linear +optimization works in revenue + +management, let us consider +a simple example -- + +a flight from New +York to Los Angeles. + +In this flight, there are +two types of economy fares, + +Early Bird fares that cost +$238, and Last Minute fares + +that cost $617. + +In this flight, a +Boeing 757 is used + +that has 166 economy seats. + +Demand for these prices +has been forecasted + +using analytics tools, +looking at historical data + +and incorporating +models like time + +series or linear regression. + +Clearly, forecasts have +errors, and therefore, we + +need to assess the +sensitivity of our decisions + +to these errors. + +To illustrate the use +of linear optimization, + +we assume that demand has +already been forecasted. + +We'll illustrate how our +decisions on how many discount + +seats to sell vary as the +demand forecasts vary. + +If the demand for +regular seats is + +50, and for discounted +fares is 150, + +and the capacity is 166 seats, +then the optimal allocation + +is going to be to sell +the 50 seats to satisfy + +the regular demand, and then +we allocate the remaining 116 + +seats to the +discounted fare class. + +If the regular demand +increases to 100 seats, + +then we allocate these 100 seats +to these customers, and only + +66 seats to discounted +fare customers. + +Finally, if the regular +demand increases to 200, + +then we allocate all of +our capacity, 166 seats, + +to these customers. + +While this seems +simple, what happens + +if we have 100 flights with +connections in tens of fares? + +We'll next see how to formulate +the problem mathematically + +and solve it in a systematic +way, using linear optimization. \ No newline at end of file diff --git a/MWcO8ZTOQQQ.txt b/MWcO8ZTOQQQ.txt new file mode 100644 index 0000000000000000000000000000000000000000..b2c963fac59b27f656d545fb23493808d9829e59 --- /dev/null +++ b/MWcO8ZTOQQQ.txt @@ -0,0 +1,2611 @@ +align:start position:0% + +in this segment we look into the + + align:start position:0% +in this segment we look into the + + + align:start position:0% +in this segment we look into the +probability that the sum of N + + align:start position:0% +probability that the sum of N + + + align:start position:0% +probability that the sum of N +independent identically distributed + + align:start position:0% +independent identically distributed + + + align:start position:0% +independent identically distributed +random variables takes an abnormally + + align:start position:0% +random variables takes an abnormally + + + align:start position:0% +random variables takes an abnormally +large + + align:start position:0% +large + + + align:start position:0% +large +value we will get an upper bound on this + + align:start position:0% +value we will get an upper bound on this + + + align:start position:0% +value we will get an upper bound on this +quantity which is known as hings + + align:start position:0% +quantity which is known as hings + + + align:start position:0% +quantity which is known as hings +inequality this is an upper bound that + + align:start position:0% +inequality this is an upper bound that + + + align:start position:0% +inequality this is an upper bound that +applies to a special case although the + + align:start position:0% +applies to a special case although the + + + align:start position:0% +applies to a special case although the +method actually generalizes here is the + + align:start position:0% +method actually generalizes here is the + + + align:start position:0% +method actually generalizes here is the +special case that we will consider the + + align:start position:0% +special case that we will consider the + + + align:start position:0% +special case that we will consider the +random variables the XIs are equally + + align:start position:0% +random variables the XIs are equally + + + align:start position:0% +random variables the XIs are equally +likely to take the values minus one and + + align:start position:0% +likely to take the values minus one and + + + align:start position:0% +likely to take the values minus one and ++ one with equal + + align:start position:0% ++ one with equal + + + align:start position:0% ++ one with equal +probability and we're interested in the + + align:start position:0% +probability and we're interested in the + + + align:start position:0% +probability and we're interested in the +random variable which is the sum of the + + align:start position:0% + + + + align:start position:0% + +X's what do we know about this random + + align:start position:0% +X's what do we know about this random + + + align:start position:0% +X's what do we know about this random +variable well the expected value of each + + align:start position:0% +variable well the expected value of each + + + align:start position:0% +variable well the expected value of each +one of the XIs is equal to zero because + + align:start position:0% +one of the XIs is equal to zero because + + + align:start position:0% +one of the XIs is equal to zero because +the distribution is symmetric and also + + align:start position:0% +the distribution is symmetric and also + + + align:start position:0% +the distribution is symmetric and also +the distance of XI from the mean has + + align:start position:0% +the distance of XI from the mean has + + + align:start position:0% +the distance of XI from the mean has +always magnitude one and for this reason + + align:start position:0% +always magnitude one and for this reason + + + align:start position:0% +always magnitude one and for this reason +the variance of the x i is equal to one + + align:start position:0% +the variance of the x i is equal to one + + + align:start position:0% +the variance of the x i is equal to one +for this reason the random variable y + + align:start position:0% +for this reason the random variable y + + + align:start position:0% +for this reason the random variable y +has a mean of + + align:start position:0% +has a mean of + + + align:start position:0% +has a mean of +zero and a variance equal to + + align:start position:0% + + + + align:start position:0% + +n now what do we know about the random + + align:start position:0% +n now what do we know about the random + + + align:start position:0% +n now what do we know about the random +variable y by the center limit theorem y + + align:start position:0% +variable y by the center limit theorem y + + + align:start position:0% +variable y by the center limit theorem y +has an approximately nor normal + + align:start position:0% +has an approximately nor normal + + + align:start position:0% +has an approximately nor normal +distribution the distribution is + + align:start position:0% +distribution the distribution is + + + align:start position:0% +distribution the distribution is +centered at + + align:start position:0% +centered at + + + align:start position:0% +centered at +zero and + + align:start position:0% +zero and + + + align:start position:0% +zero and +also the random variable y over square + + align:start position:0% +also the random variable y over square + + + align:start position:0% +also the random variable y over square +otk of n this is a standardized random + + align:start position:0% +otk of n this is a standardized random + + + align:start position:0% +otk of n this is a standardized random +variable so it's approximately normal + + align:start position:0% +variable so it's approximately normal + + + align:start position:0% +variable so it's approximately normal +and so the probability that this number + + align:start position:0% +and so the probability that this number + + + align:start position:0% +and so the probability that this number +is larger than or equal to some a is + + align:start position:0% +is larger than or equal to some a is + + + align:start position:0% +is larger than or equal to some a is +approximately 1 minus the cumulative of + + align:start position:0% +approximately 1 minus the cumulative of + + + align:start position:0% +approximately 1 minus the cumulative of +the standard normal so F here stands for + + align:start position:0% +the standard normal so F here stands for + + + align:start position:0% +the standard normal so F here stands for +the standard normal + + align:start position:0% + + + + align:start position:0% + +CDF what does this tell us it tells us + + align:start position:0% +CDF what does this tell us it tells us + + + align:start position:0% +CDF what does this tell us it tells us +that if we take somewhere here the + + align:start position:0% +that if we take somewhere here the + + + align:start position:0% +that if we take somewhere here the +number Square < TK of n * + + align:start position:0% +number Square < TK of n * + + + align:start position:0% +number Square < TK of n * +a then this probability down here in the + + align:start position:0% +a then this probability down here in the + + + align:start position:0% +a then this probability down here in the +tail is approximately constant no matter + + align:start position:0% +tail is approximately constant no matter + + + align:start position:0% +tail is approximately constant no matter +what n is and this particular tells us + + align:start position:0% +what n is and this particular tells us + + + align:start position:0% +what n is and this particular tells us +that values of the order of square root + + align:start position:0% +that values of the order of square root + + + align:start position:0% +that values of the order of square root +n are fairly likely to + + align:start position:0% +n are fairly likely to + + + align:start position:0% +n are fairly likely to +occur however what we're interested in + + align:start position:0% +occur however what we're interested in + + + align:start position:0% +occur however what we're interested in +here is not being larger than square + + align:start position:0% +here is not being larger than square + + + align:start position:0% +here is not being larger than square +root n * a we're interested in being + + align:start position:0% +root n * a we're interested in being + + + align:start position:0% +root n * a we're interested in being +larger than n * a so we're talking about + + align:start position:0% +larger than n * a so we're talking about + + + align:start position:0% +larger than n * a so we're talking about +what happens further down in the tail of + + align:start position:0% +what happens further down in the tail of + + + align:start position:0% +what happens further down in the tail of +the distribution so if we take here n * + + align:start position:0% +the distribution so if we take here n * + + + align:start position:0% +the distribution so if we take here n * +a we're looking at this prob probability + + align:start position:0% +a we're looking at this prob probability + + + align:start position:0% +a we're looking at this prob probability +down here and we want to ask how small + + align:start position:0% +down here and we want to ask how small + + + align:start position:0% +down here and we want to ask how small +is that + + align:start position:0% +is that + + + align:start position:0% +is that +probability well we have chfs in + + align:start position:0% +probability well we have chfs in + + + align:start position:0% +probability well we have chfs in +equality and chf's inequality tells us + + align:start position:0% +equality and chf's inequality tells us + + + align:start position:0% +equality and chf's inequality tells us +that the probability of Y being larger + + align:start position:0% +that the probability of Y being larger + + + align:start position:0% +that the probability of Y being larger +than a certain number is less than or + + align:start position:0% +than a certain number is less than or + + + align:start position:0% +than a certain number is less than or +equal to the variance of Y divided by + + align:start position:0% +equal to the variance of Y divided by + + + align:start position:0% +equal to the variance of Y divided by +the square of that + + align:start position:0% + + + + align:start position:0% + +number and in this case since the + + align:start position:0% +number and in this case since the + + + align:start position:0% +number and in this case since the +variance is n this is 1 / n a s + + align:start position:0% +variance is n this is 1 / n a s + + + align:start position:0% +variance is n this is 1 / n a s +so CH Bish's inequality tells us that + + align:start position:0% +so CH Bish's inequality tells us that + + + align:start position:0% +so CH Bish's inequality tells us that +this probability goes to zero and it + + align:start position:0% +this probability goes to zero and it + + + align:start position:0% +this probability goes to zero and it +goes to zero at least as fast as 1 / n + + align:start position:0% +goes to zero at least as fast as 1 / n + + + align:start position:0% +goes to zero at least as fast as 1 / n +goes to zero however it turns out that + + align:start position:0% +goes to zero however it turns out that + + + align:start position:0% +goes to zero however it turns out that +this is extremely conservative herting + + align:start position:0% +this is extremely conservative herting + + + align:start position:0% +this is extremely conservative herting +inequality which we are going to + + align:start position:0% +inequality which we are going to + + + align:start position:0% +inequality which we are going to +establish tells us something much + + align:start position:0% +establish tells us something much + + + align:start position:0% +establish tells us something much +stronger it tells us that this tail + + align:start position:0% +stronger it tells us that this tail + + + align:start position:0% +stronger it tells us that this tail +probability down here Falls + + align:start position:0% +probability down here Falls + + + align:start position:0% +probability down here Falls +exponentially with + + align:start position:0% +exponentially with + + + align:start position:0% +exponentially with +n so this is what we want to show and + + align:start position:0% +n so this is what we want to show and + + + align:start position:0% +n so this is what we want to show and +let us get started to see how the + + align:start position:0% +let us get started to see how the + + + align:start position:0% +let us get started to see how the +derivation + + align:start position:0% +derivation + + + align:start position:0% +derivation +goes the derivation relies on a + + align:start position:0% +goes the derivation relies on a + + + align:start position:0% +goes the derivation relies on a +beautiful + + align:start position:0% +beautiful + + + align:start position:0% +beautiful +trick instead of looking at this event + + align:start position:0% +trick instead of looking at this event + + + align:start position:0% +trick instead of looking at this event +here we're going to look at the + + align:start position:0% +here we're going to look at the + + + align:start position:0% +here we're going to look at the +following equivalent + + align:start position:0% + + + + align:start position:0% + +event let us fix some number + + align:start position:0% +event let us fix some number + + + align:start position:0% +event let us fix some number +s we're going to leave the choice of s + + align:start position:0% +s we're going to leave the choice of s + + + align:start position:0% +s we're going to leave the choice of s +free for now + + align:start position:0% +free for now + + + align:start position:0% +free for now +it is only that we're going to assume + + align:start position:0% +it is only that we're going to assume + + + align:start position:0% +it is only that we're going to assume +that s is a positive + + align:start position:0% + + + + align:start position:0% + +number and throughout we're also + + align:start position:0% +number and throughout we're also + + + align:start position:0% +number and throughout we're also +assuming that a is also a positive + + align:start position:0% +assuming that a is also a positive + + + align:start position:0% +assuming that a is also a positive +number now we look at this quantity and + + align:start position:0% +number now we look at this quantity and + + + align:start position:0% +number now we look at this quantity and +the event that this quantity is larger + + align:start position:0% +the event that this quantity is larger + + + align:start position:0% +the event that this quantity is larger +than or equal to e to the s n * + + align:start position:0% +than or equal to e to the s n * + + + align:start position:0% +than or equal to e to the s n * +a now this sum is larger than or equal + + align:start position:0% +a now this sum is larger than or equal + + + align:start position:0% +a now this sum is larger than or equal +to na a if and only if this quantity is + + align:start position:0% +to na a if and only if this quantity is + + + align:start position:0% +to na a if and only if this quantity is +larger than or equal to e to the S NA a + + align:start position:0% +larger than or equal to e to the S NA a + + + align:start position:0% +larger than or equal to e to the S NA a +this is because A and S are both + + align:start position:0% +this is because A and S are both + + + align:start position:0% +this is because A and S are both +positive so the direction of the + + align:start position:0% +positive so the direction of the + + + align:start position:0% +positive so the direction of the +inequalities does not get reversed and + + align:start position:0% +inequalities does not get reversed and + + + align:start position:0% +inequalities does not get reversed and +also because the exponential function is + + align:start position:0% +also because the exponential function is + + + align:start position:0% +also because the exponential function is +monotonic so this event is the same as + + align:start position:0% +monotonic so this event is the same as + + + align:start position:0% +monotonic so this event is the same as +that + + align:start position:0% +that + + + align:start position:0% +that +event so we will try to say something + + align:start position:0% +event so we will try to say something + + + align:start position:0% +event so we will try to say something +about the probability of this event how + + align:start position:0% +about the probability of this event how + + + align:start position:0% +about the probability of this event how +are we going to do it we will use the + + align:start position:0% +are we going to do it we will use the + + + align:start position:0% +are we going to do it we will use the +mark of inequality where Z is the random + + align:start position:0% +mark of inequality where Z is the random + + + align:start position:0% +mark of inequality where Z is the random +variable that appears here so by Mark of + + align:start position:0% +variable that appears here so by Mark of + + + align:start position:0% +variable that appears here so by Mark of +inequality this probability is less than + + align:start position:0% +inequality this probability is less than + + + align:start position:0% +inequality this probability is less than +or equal to the expected value of the + + align:start position:0% +or equal to the expected value of the + + + align:start position:0% +or equal to the expected value of the +random variable that we are dealing + + align:start position:0% + + + + align:start position:0% + +with divided by this value + + align:start position:0% + + + + align:start position:0% + +now the exponential of a sum we can + + align:start position:0% +now the exponential of a sum we can + + + align:start position:0% +now the exponential of a sum we can +Factor it as a product of + + align:start position:0% + + + + align:start position:0% + +exponentials and then we use the + + align:start position:0% +exponentials and then we use the + + + align:start position:0% +exponentials and then we use the +assumption that the X's are + + align:start position:0% +assumption that the X's are + + + align:start position:0% +assumption that the X's are +independent since the X's are + + align:start position:0% +independent since the X's are + + + align:start position:0% +independent since the X's are +independent e to the sx1 is independent + + align:start position:0% +independent e to the sx1 is independent + + + align:start position:0% +independent e to the sx1 is independent +from e to the sx2 and so on and so we + + align:start position:0% +from e to the sx2 and so on and so we + + + align:start position:0% +from e to the sx2 and so on and so we +have the expected value of a product of + + align:start position:0% +have the expected value of a product of + + + align:start position:0% +have the expected value of a product of +independent random variables and so this + + align:start position:0% +independent random variables and so this + + + align:start position:0% +independent random variables and so this +is equal to the product of the + + align:start position:0% +is equal to the product of the + + + align:start position:0% +is equal to the product of the +expectations so we are going to multiply + + align:start position:0% +expectations so we are going to multiply + + + align:start position:0% +expectations so we are going to multiply +the expected value of e to the S + + align:start position:0% +the expected value of e to the S + + + align:start position:0% +the expected value of e to the S +X1 with the expected value of e to the + + align:start position:0% +X1 with the expected value of e to the + + + align:start position:0% +X1 with the expected value of e to the +sx2 and so on but because all the XIs + + align:start position:0% +sx2 and so on but because all the XIs + + + align:start position:0% +sx2 and so on but because all the XIs +are identically distributed the terms + + align:start position:0% +are identically distributed the terms + + + align:start position:0% +are identically distributed the terms +that we get are all the same so we get + + align:start position:0% +that we get are all the same so we get + + + align:start position:0% +that we get are all the same so we get +this term to the nth power divided Again + + align:start position:0% +this term to the nth power divided Again + + + align:start position:0% +this term to the nth power divided Again +by e to the SN + + align:start position:0% +by e to the SN + + + align:start position:0% +by e to the SN +a or we can write this in more + + align:start position:0% +a or we can write this in more + + + align:start position:0% +a or we can write this in more +suggestive form as + + align:start position:0% +suggestive form as + + + align:start position:0% +suggestive form as +follows it's the expected value of e to + + align:start position:0% +follows it's the expected value of e to + + + align:start position:0% +follows it's the expected value of e to +the S + + align:start position:0% +the S + + + align:start position:0% +the S +X1 divided by e to the sa a all that to + + align:start position:0% +X1 divided by e to the sa a all that to + + + align:start position:0% +X1 divided by e to the sa a all that to +the nth power so think of that as being + + align:start position:0% +the nth power so think of that as being + + + align:start position:0% +the nth power so think of that as being +some number raw to the nth + + align:start position:0% +some number raw to the nth + + + align:start position:0% +some number raw to the nth +power when is this bound going to be + + align:start position:0% +power when is this bound going to be + + + align:start position:0% +power when is this bound going to be +interesting it's going to be interesting + + align:start position:0% +interesting it's going to be interesting + + + align:start position:0% +interesting it's going to be interesting +if raow is less than one because in that + + align:start position:0% +if raow is less than one because in that + + + align:start position:0% +if raow is less than one because in that +case this bound Falls exponentially with + + align:start position:0% +case this bound Falls exponentially with + + + align:start position:0% +case this bound Falls exponentially with +n and so this probability in particular + + align:start position:0% +n and so this probability in particular + + + align:start position:0% +n and so this probability in particular +will fall exponentially with + + align:start position:0% + + + + align:start position:0% + +n the key here is that we have freedom + + align:start position:0% +n the key here is that we have freedom + + + align:start position:0% +n the key here is that we have freedom +to choose s for any value of s we obtain + + align:start position:0% +to choose s for any value of s we obtain + + + align:start position:0% +to choose s for any value of s we obtain +an upper bound we're going to choose s + + align:start position:0% +an upper bound we're going to choose s + + + align:start position:0% +an upper bound we're going to choose s +so that we get the most informative or a + + align:start position:0% +so that we get the most informative or a + + + align:start position:0% +so that we get the most informative or a +most powerful upper + + align:start position:0% +most powerful upper + + + align:start position:0% +most powerful upper +bound so let us continue to see what we + + align:start position:0% +bound so let us continue to see what we + + + align:start position:0% +bound so let us continue to see what we +can do first let us write down what this + + align:start position:0% +can do first let us write down what this + + + align:start position:0% +can do first let us write down what this +expected value + + align:start position:0% +expected value + + + align:start position:0% +expected value +is since + + align:start position:0% +is since + + + align:start position:0% +is since +X1 takes values minus one or+ one with + + align:start position:0% +X1 takes values minus one or+ one with + + + align:start position:0% +X1 takes values minus one or+ one with +equal probability this expectation is + + align:start position:0% +equal probability this expectation is + + + align:start position:0% +equal probability this expectation is +the following with probability 1 12 X1 + + align:start position:0% +the following with probability 1 12 X1 + + + align:start position:0% +the following with probability 1 12 X1 +takes the value of one and so this + + align:start position:0% +takes the value of one and so this + + + align:start position:0% +takes the value of one and so this +random variable is e to the S and with + + align:start position:0% +random variable is e to the S and with + + + align:start position:0% +random variable is e to the S and with +probability 1/2 it takes the value minus + + align:start position:0% +probability 1/2 it takes the value minus + + + align:start position:0% +probability 1/2 it takes the value minus +one in which case this random variable + + align:start position:0% +one in which case this random variable + + + align:start position:0% +one in which case this random variable +is e to the minus s so this is the + + align:start position:0% +is e to the minus s so this is the + + + align:start position:0% +is e to the minus s so this is the +expectation in the numerator and we + + align:start position:0% +expectation in the numerator and we + + + align:start position:0% +expectation in the numerator and we +write again the term in the + + align:start position:0% +write again the term in the + + + align:start position:0% +write again the term in the +denominator and we have all this to the + + align:start position:0% +denominator and we have all this to the + + + align:start position:0% +denominator and we have all this to the +power n if we can choose s so that this + + align:start position:0% +power n if we can choose s so that this + + + align:start position:0% +power n if we can choose s so that this +quantity is less than one we will have + + align:start position:0% +quantity is less than one we will have + + + align:start position:0% +quantity is less than one we will have +achieved our + + align:start position:0% +achieved our + + + align:start position:0% +achieved our +objective can we do + + align:start position:0% +objective can we do + + + align:start position:0% +objective can we do +that let's see let's look at the + + align:start position:0% +that let's see let's look at the + + + align:start position:0% +that let's see let's look at the +numerator as a function of + + align:start position:0% +numerator as a function of + + + align:start position:0% +numerator as a function of +s when s is equal to zero we have 1 + 1/ + + align:start position:0% +s when s is equal to zero we have 1 + 1/ + + + align:start position:0% +s when s is equal to zero we have 1 + 1/ +by2 that gives us + + align:start position:0% +by2 that gives us + + + align:start position:0% +by2 that gives us +1 and then as s moves away from zero + + align:start position:0% +1 and then as s moves away from zero + + + align:start position:0% +1 and then as s moves away from zero +this function will have this kind of + + align:start position:0% +this function will have this kind of + + + align:start position:0% +this function will have this kind of +shape and it is symmet ATC around zero + + align:start position:0% +shape and it is symmet ATC around zero + + + align:start position:0% +shape and it is symmet ATC around zero +because we have an S and A minus s + + align:start position:0% +because we have an S and A minus s + + + align:start position:0% +because we have an S and A minus s +here in particular the derivative of + + align:start position:0% +here in particular the derivative of + + + align:start position:0% +here in particular the derivative of +this function is 0 at 0o let's look at + + align:start position:0% +this function is 0 at 0o let's look at + + + align:start position:0% +this function is 0 at 0o let's look at +the denominator term the denominator + + align:start position:0% +the denominator term the denominator + + + align:start position:0% +the denominator term the denominator +term is an + + align:start position:0% +term is an + + + align:start position:0% +term is an +exponential a is a positive number so + + align:start position:0% +exponential a is a positive number so + + + align:start position:0% +exponential a is a positive number so +it's an exponential that has a shape of + + align:start position:0% +it's an exponential that has a shape of + + + align:start position:0% +it's an exponential that has a shape of +this + + align:start position:0% + + + + align:start position:0% + +kind the important thing to notice is + + align:start position:0% +kind the important thing to notice is + + + align:start position:0% +kind the important thing to notice is +that this exponential has a positive + + align:start position:0% +that this exponential has a positive + + + align:start position:0% +that this exponential has a positive +derivative at + + align:start position:0% +derivative at + + + align:start position:0% +derivative at +zero what does that tell us that at + + align:start position:0% +zero what does that tell us that at + + + align:start position:0% +zero what does that tell us that at +least in the vicinity of + + align:start position:0% +least in the vicinity of + + + align:start position:0% +least in the vicinity of +zero this term the denominator is going + + align:start position:0% +zero this term the denominator is going + + + align:start position:0% +zero this term the denominator is going +to be larger than the numerator term and + + align:start position:0% +to be larger than the numerator term and + + + align:start position:0% +to be larger than the numerator term and +that implies that in the vicinity of + + align:start position:0% +that implies that in the vicinity of + + + align:start position:0% +that implies that in the vicinity of +zero this fraction is going to be less + + align:start position:0% +zero this fraction is going to be less + + + align:start position:0% +zero this fraction is going to be less +than + + align:start position:0% +than + + + align:start position:0% +than +one and we will have achieved our goal + + align:start position:0% +one and we will have achieved our goal + + + align:start position:0% +one and we will have achieved our goal +of an exponentially decay G + + align:start position:0% + + + + align:start position:0% + +bound so the conclusion is that for + + align:start position:0% +bound so the conclusion is that for + + + align:start position:0% +bound so the conclusion is that for +small + + align:start position:0% + + + + align:start position:0% + +s we have that raw is less than + + align:start position:0% +s we have that raw is less than + + + align:start position:0% +s we have that raw is less than +one now we would like to get an explicit + + align:start position:0% +one now we would like to get an explicit + + + align:start position:0% +one now we would like to get an explicit +value for raw and we will do that by + + align:start position:0% +value for raw and we will do that by + + + align:start position:0% +value for raw and we will do that by +fixing a specific value for S it turns + + align:start position:0% +fixing a specific value for S it turns + + + align:start position:0% +fixing a specific value for S it turns +out that if we set s to be equal to a + + align:start position:0% +out that if we set s to be equal to a + + + align:start position:0% +out that if we set s to be equal to a +then the bound that we get is going to + + align:start position:0% +then the bound that we get is going to + + + align:start position:0% +then the bound that we get is going to +be that this probability here is less + + align:start position:0% +be that this probability here is less + + + align:start position:0% +be that this probability here is less +than or equal to e to Theus N A + + align:start position:0% +than or equal to e to Theus N A + + + align:start position:0% +than or equal to e to Theus N A +2 over + + align:start position:0% +2 over + + + align:start position:0% +2 over +2 and this is the hefting + + align:start position:0% + + + + align:start position:0% + +bound at this point you may just + + align:start position:0% +bound at this point you may just + + + align:start position:0% +bound at this point you may just +pause or if you're curious you can + + align:start position:0% +pause or if you're curious you can + + + align:start position:0% +pause or if you're curious you can +continue with this video to see the + + align:start position:0% +continue with this video to see the + + + align:start position:0% +continue with this video to see the +algebraic manipulations involved in + + align:start position:0% +algebraic manipulations involved in + + + align:start position:0% +algebraic manipulations involved in +order to show that this expression is + + align:start position:0% +order to show that this expression is + + + align:start position:0% +order to show that this expression is +less than or equal to that + + align:start position:0% +less than or equal to that + + + align:start position:0% +less than or equal to that +expression but before going there I + + align:start position:0% +expression but before going there I + + + align:start position:0% +expression but before going there I +would like to make a general comment + + align:start position:0% +would like to make a general comment + + + align:start position:0% +would like to make a general comment +even if the X's had a different + + align:start position:0% +even if the X's had a different + + + align:start position:0% +even if the X's had a different +distribution but with zero mean the + + align:start position:0% +distribution but with zero mean the + + + align:start position:0% +distribution but with zero mean the +derivation up to this point would go + + align:start position:0% +derivation up to this point would go + + + align:start position:0% +derivation up to this point would go +through here you would have a somewhat + + align:start position:0% +through here you would have a somewhat + + + align:start position:0% +through here you would have a somewhat +different expression for the expected + + align:start position:0% +different expression for the expected + + + align:start position:0% +different expression for the expected +value of e to the s + + align:start position:0% +value of e to the s + + + align:start position:0% +value of e to the s +X1 however it turns out that the + + align:start position:0% +X1 however it turns out that the + + + align:start position:0% +X1 however it turns out that the +expression that you get here will always + + align:start position:0% +expression that you get here will always + + + align:start position:0% +expression that you get here will always +have this property that it has a zero + + align:start position:0% +have this property that it has a zero + + + align:start position:0% +have this property that it has a zero +derivative this is a consequence of the + + align:start position:0% +derivative this is a consequence of the + + + align:start position:0% +derivative this is a consequence of the +assumption that we assumed zero mean and + + align:start position:0% +assumption that we assumed zero mean and + + + align:start position:0% +assumption that we assumed zero mean and +because of that we will still have a + + align:start position:0% +because of that we will still have a + + + align:start position:0% +because of that we will still have a +picture of this kind and so this + + align:start position:0% +picture of this kind and so this + + + align:start position:0% +picture of this kind and so this +fraction will always be less than one + + align:start position:0% +fraction will always be less than one + + + align:start position:0% +fraction will always be less than one +when we choose s to be suitably small + + align:start position:0% +when we choose s to be suitably small + + + align:start position:0% +when we choose s to be suitably small +and so this is going to give us a + + align:start position:0% +and so this is going to give us a + + + align:start position:0% +and so this is going to give us a +results for more General distributions + + align:start position:0% +results for more General distributions + + + align:start position:0% +results for more General distributions +and that more General result is known as + + align:start position:0% +and that more General result is known as + + + align:start position:0% +and that more General result is known as +the churn of + + align:start position:0% + + + + align:start position:0% + +bound however we will not develop in + + align:start position:0% +bound however we will not develop in + + + align:start position:0% +bound however we will not develop in +this video the churn of bounds in its + + align:start position:0% +this video the churn of bounds in its + + + align:start position:0% +this video the churn of bounds in its +greater generality we will just stay + + align:start position:0% +greater generality we will just stay + + + align:start position:0% +greater generality we will just stay +with heing inequality that gives us the + + align:start position:0% +with heing inequality that gives us the + + + align:start position:0% +with heing inequality that gives us the +basic idea and what we will do next will + + align:start position:0% +basic idea and what we will do next will + + + align:start position:0% +basic idea and what we will do next will +be to derive this + + align:start position:0% +be to derive this + + + align:start position:0% +be to derive this +inequality so I'm carrying over what we + + align:start position:0% +inequality so I'm carrying over what we + + + align:start position:0% +inequality so I'm carrying over what we +figured out in the previous slide + + align:start position:0% +figured out in the previous slide + + + align:start position:0% +figured out in the previous slide +and this is the quantity here that we + + align:start position:0% +and this is the quantity here that we + + + align:start position:0% +and this is the quantity here that we +wish to + + align:start position:0% + + + + align:start position:0% + +bound we will look at the numerator term + + align:start position:0% +bound we will look at the numerator term + + + align:start position:0% +bound we will look at the numerator term +and we're going to use a tailor series + + align:start position:0% +and we're going to use a tailor series + + + align:start position:0% +and we're going to use a tailor series +for the exponential + + align:start position:0% +for the exponential + + + align:start position:0% +for the exponential +function remember the tailor series for + + align:start position:0% +function remember the tailor series for + + + align:start position:0% +function remember the tailor series for +the exponential function takes this form + + align:start position:0% +the exponential function takes this form + + + align:start position:0% +the exponential function takes this form +and using that we have 12 e to the S + + + align:start position:0% +and using that we have 12 e to the S + + + + align:start position:0% +and using that we have 12 e to the S + +e- S is equal to the + + align:start position:0% +e- S is equal to the + + + align:start position:0% +e- S is equal to the +following we first first write the + + align:start position:0% +following we first first write the + + + align:start position:0% +following we first first write the +tailor series for e to the S I'm just + + align:start position:0% +tailor series for e to the S I'm just + + + align:start position:0% +tailor series for e to the S I'm just +copying from here it's 1 + S + s^ 2 / 2 + + align:start position:0% +copying from here it's 1 + S + s^ 2 / 2 + + + align:start position:0% +copying from here it's 1 + S + s^ 2 / 2 +factorial plus s Cub over 3 + + align:start position:0% +factorial plus s Cub over 3 + + + align:start position:0% +factorial plus s Cub over 3 +factorial and we continue + + align:start position:0% +factorial and we continue + + + align:start position:0% +factorial and we continue +similarly and then for the term e to the + + align:start position:0% +similarly and then for the term e to the + + + align:start position:0% +similarly and then for the term e to the +minus s we have a similar expansion + + align:start position:0% +minus s we have a similar expansion + + + align:start position:0% +minus s we have a similar expansion +except that we put a minus s in the + + align:start position:0% +except that we put a minus s in the + + + align:start position:0% +except that we put a minus s in the +place of s now minus s s is the same as + + align:start position:0% +place of s now minus s s is the same as + + + align:start position:0% +place of s now minus s s is the same as +s squ with a plus + + align:start position:0% +s squ with a plus + + + align:start position:0% +s squ with a plus +sign but for S Cub when we have minus s + + align:start position:0% +sign but for S Cub when we have minus s + + + align:start position:0% +sign but for S Cub when we have minus s +this becomes Min - s cub and so on and + + align:start position:0% +this becomes Min - s cub and so on and + + + align:start position:0% +this becomes Min - s cub and so on and +so we see that in this expansion here we + + align:start position:0% +so we see that in this expansion here we + + + align:start position:0% +so we see that in this expansion here we +will alternate between positive and + + align:start position:0% +will alternate between positive and + + + align:start position:0% +will alternate between positive and +negative signs this means that all the + + align:start position:0% +negative signs this means that all the + + + align:start position:0% +negative signs this means that all the +odd power terms will cancel each other + + align:start position:0% +odd power terms will cancel each other + + + align:start position:0% +odd power terms will cancel each other +but the even power terms Will + + align:start position:0% +but the even power terms Will + + + align:start position:0% +but the even power terms Will +Survive so what we obtain is + + align:start position:0% +Survive so what we obtain is + + + align:start position:0% +Survive so what we obtain is +the + + align:start position:0% +the + + + align:start position:0% +the +sum of all those + + align:start position:0% + + + + align:start position:0% + +terms but we only have the even power + + align:start position:0% +terms but we only have the even power + + + align:start position:0% +terms but we only have the even power +terms so we have powers of the form 2 I + + align:start position:0% +terms so we have powers of the form 2 I + + + align:start position:0% +terms so we have powers of the form 2 I +these are the even + + align:start position:0% +these are the even + + + align:start position:0% +these are the even +integers and in the denominators we will + + align:start position:0% +integers and in the denominators we will + + + align:start position:0% +integers and in the denominators we will +always have the factorial of whatever + + align:start position:0% +always have the factorial of whatever + + + align:start position:0% +always have the factorial of whatever +exponent we have at the top + + align:start position:0% + + + + align:start position:0% + +now let us get a bound on this term in + + align:start position:0% +now let us get a bound on this term in + + + align:start position:0% +now let us get a bound on this term in +the + + align:start position:0% +the + + + align:start position:0% +the +denominator 2 I + + align:start position:0% +denominator 2 I + + + align:start position:0% +denominator 2 I +factorial is 1 * 2 * 3 all the way up to + + align:start position:0% +factorial is 1 * 2 * 3 all the way up to + + + align:start position:0% +factorial is 1 * 2 * 3 all the way up to +I and then we continue I + 1 I + 2 all + + align:start position:0% +I and then we continue I + 1 I + 2 all + + + align:start position:0% +I and then we continue I + 1 I + 2 all +the way up to 2 + + align:start position:0% +the way up to 2 + + + align:start position:0% +the way up to 2 +I and what we have is first I factorial + + align:start position:0% + + + + align:start position:0% + +but then each one of these terms is + + align:start position:0% +but then each one of these terms is + + + align:start position:0% +but then each one of these terms is +larger than or equal to two and we have + + align:start position:0% +larger than or equal to two and we have + + + align:start position:0% +larger than or equal to two and we have +I such terms and this gives us this + + align:start position:0% +I such terms and this gives us this + + + align:start position:0% +I such terms and this gives us this +inequality so we're going to use this + + align:start position:0% +inequality so we're going to use this + + + align:start position:0% +inequality so we're going to use this +substitution here because this term is + + align:start position:0% +substitution here because this term is + + + align:start position:0% +substitution here because this term is +in the denominator the direction of the + + align:start position:0% +in the denominator the direction of the + + + align:start position:0% +in the denominator the direction of the +inequality is going to be reversed and + + align:start position:0% +inequality is going to be reversed and + + + align:start position:0% +inequality is going to be reversed and +we obtain this + + align:start position:0% + + + + align:start position:0% + +now we can rewrite this by taking this + + align:start position:0% +now we can rewrite this by taking this + + + align:start position:0% +now we can rewrite this by taking this +term 2 to the I and combining it with + + align:start position:0% +term 2 to the I and combining it with + + + align:start position:0% +term 2 to the I and combining it with +the other term in the + + align:start position:0% + + + + align:start position:0% + +numerator and what we have is s² / 2 all + + align:start position:0% +numerator and what we have is s² / 2 all + + + align:start position:0% +numerator and what we have is s² / 2 all +of that to the ice power + + align:start position:0% + + + + align:start position:0% + +now does this expression look + + align:start position:0% +now does this expression look + + + align:start position:0% +now does this expression look +familiar it is of exactly the same form + + align:start position:0% +familiar it is of exactly the same form + + + align:start position:0% +familiar it is of exactly the same form +as this expansion but instead of s we + + align:start position:0% +as this expansion but instead of s we + + + align:start position:0% +as this expansion but instead of s we +now have S squ over 2 therefore this is + + align:start position:0% +now have S squ over 2 therefore this is + + + align:start position:0% +now have S squ over 2 therefore this is +equal to e to the + + align:start position:0% +equal to e to the + + + align:start position:0% +equal to e to the +s² / + + align:start position:0% +s² / + + + align:start position:0% +s² / +2 so we managed to + + align:start position:0% +2 so we managed to + + + align:start position:0% +2 so we managed to +bound this term using now this bound we + + align:start position:0% +bound this term using now this bound we + + + align:start position:0% +bound this term using now this bound we +go back to this + + align:start position:0% +go back to this + + + align:start position:0% +go back to this +inequality and we have that this is less + + align:start position:0% +inequality and we have that this is less + + + align:start position:0% +inequality and we have that this is less +than or equal + + align:start position:0% +than or equal + + + align:start position:0% +than or equal +to in the numerator we have e to the + + align:start position:0% +to in the numerator we have e to the + + + align:start position:0% +to in the numerator we have e to the +s² over two in the denominator we have e + + align:start position:0% +s² over two in the denominator we have e + + + align:start position:0% +s² over two in the denominator we have e +to the sa + + align:start position:0% +to the sa + + + align:start position:0% +to the sa +a and all that is raised to the nth + + align:start position:0% +a and all that is raised to the nth + + + align:start position:0% +a and all that is raised to the nth +power or another way to write this is e + + align:start position:0% +power or another way to write this is e + + + align:start position:0% +power or another way to write this is e +to the s² / + + align:start position:0% + + + + align:start position:0% + +2 minus + + align:start position:0% +2 minus + + + align:start position:0% +2 minus +sa and all that to the nth + + align:start position:0% +sa and all that to the nth + + + align:start position:0% +sa and all that to the nth +power and now if I choose s equal to + + align:start position:0% + + + + align:start position:0% + +a what I obtain here is going to be e to + + align:start position:0% +a what I obtain here is going to be e to + + + align:start position:0% +a what I obtain here is going to be e to +the a^ 2 / 2 - a^ 2 that leaves me me + + align:start position:0% +the a^ 2 / 2 - a^ 2 that leaves me me + + + align:start position:0% +the a^ 2 / 2 - a^ 2 that leaves me me +with e to the minus a^ 2 / 2 and then I + + align:start position:0% +with e to the minus a^ 2 / 2 and then I + + + align:start position:0% +with e to the minus a^ 2 / 2 and then I +take this factor of n as well and the + + align:start position:0% +take this factor of n as well and the + + + align:start position:0% +take this factor of n as well and the +final + + align:start position:0% +final + + + align:start position:0% +final +conclusion is that this quantity becomes + + align:start position:0% +conclusion is that this quantity becomes + + + align:start position:0% +conclusion is that this quantity becomes +equal to this + + align:start position:0% +equal to this + + + align:start position:0% +equal to this +term and so we have completed the + + align:start position:0% +term and so we have completed the + + + align:start position:0% +term and so we have completed the +derivation that this expression is less + + align:start position:0% +derivation that this expression is less + + + align:start position:0% +derivation that this expression is less +than or equal to this quantity when we + + align:start position:0% +than or equal to this quantity when we + + + align:start position:0% +than or equal to this quantity when we +choose s equal to a and this is heing + + align:start position:0% +choose s equal to a and this is heing + + + align:start position:0% +choose s equal to a and this is heing +inequality \ No newline at end of file diff --git a/MuNpOg4W7jk.txt b/MuNpOg4W7jk.txt new file mode 100644 index 0000000000000000000000000000000000000000..214a13d3c27b68b40b2213a388bb6873f41c5aa1 --- /dev/null +++ b/MuNpOg4W7jk.txt @@ -0,0 +1,16427 @@ +align:start position:0% + +I'm going to talk about building the + + align:start position:0% +I'm going to talk about building the + + + align:start position:0% +I'm going to talk about building the +health system so that technology or + + align:start position:0% +health system so that technology or + + + align:start position:0% +health system so that technology or +platforms again some jargon that I I + + align:start position:0% +platforms again some jargon that I I + + + align:start position:0% +platforms again some jargon that I I +really learned + + align:start position:0% +really learned + + + align:start position:0% +really learned +um from people with trainings like some + + align:start position:0% +um from people with trainings like some + + + align:start position:0% +um from people with trainings like some +of those in this room how can we use + + align:start position:0% +of those in this room how can we use + + + align:start position:0% +of those in this room how can we use +those platforms to innovate or you know + + align:start position:0% +those platforms to innovate or you know + + + align:start position:0% +those platforms to innovate or you know +you've heard all the Expressions since + + align:start position:0% +you've heard all the Expressions since + + + align:start position:0% +you've heard all the Expressions since +then leapfrog leapfrog Innovations + + align:start position:0% +then leapfrog leapfrog Innovations + + + align:start position:0% +then leapfrog leapfrog Innovations +disruptive Innovations + + align:start position:0% +disruptive Innovations + + + align:start position:0% +disruptive Innovations +one of the ways that that can work is to + + align:start position:0% +one of the ways that that can work is to + + + align:start position:0% +one of the ways that that can work is to +not have systems and systems advice you + + align:start position:0% +not have systems and systems advice you + + + align:start position:0% +not have systems and systems advice you +can build around another is to have + + align:start position:0% +can build around another is to have + + + align:start position:0% +can build around another is to have +decent elastic ones so I'm going to talk + + align:start position:0% +decent elastic ones so I'm going to talk + + + align:start position:0% +decent elastic ones so I'm going to talk +about that part how do you deliver + + align:start position:0% +about that part how do you deliver + + + align:start position:0% +about that part how do you deliver +Services what how do you what is Health + + align:start position:0% +Services what how do you what is Health + + + align:start position:0% +Services what how do you what is Health +System strengthening and I would like to + + align:start position:0% +System strengthening and I would like to + + + align:start position:0% +System strengthening and I would like to +end fairly early so that this can be a + + align:start position:0% +end fairly early so that this can be a + + + align:start position:0% +end fairly early so that this can be a +good discussion for for me as well and + + align:start position:0% +good discussion for for me as well and + + + align:start position:0% +good discussion for for me as well and +and my colleagues are here too in + + align:start position:0% +and my colleagues are here too in + + + align:start position:0% +and my colleagues are here too in +addition to Hamish Renee and their team + + align:start position:0% +addition to Hamish Renee and their team + + + align:start position:0% +addition to Hamish Renee and their team +with me today is Claire Pierre who's + + align:start position:0% +with me today is Claire Pierre who's + + + align:start position:0% +with me today is Claire Pierre who's +worked at an I.T and Health Systems in + + align:start position:0% +worked at an I.T and Health Systems in + + + align:start position:0% +worked at an I.T and Health Systems in +Cambridge Massachusetts and in uh in + + align:start position:0% +Cambridge Massachusetts and in uh in + + + align:start position:0% +Cambridge Massachusetts and in uh in +Haiti and Emily bonson + + align:start position:0% +Haiti and Emily bonson + + + align:start position:0% +Haiti and Emily bonson +um who is + + align:start position:0% +um who is + + + align:start position:0% +um who is +anyway I'm her right hand let's put it + + align:start position:0% +anyway I'm her right hand let's put it + + + align:start position:0% +anyway I'm her right hand let's put it +that way so I want to talk a little bit + + align:start position:0% +that way so I want to talk a little bit + + + align:start position:0% +that way so I want to talk a little bit +about basic health design + + align:start position:0% +about basic health design + + + align:start position:0% +about basic health design +um and and we'll be focusing on Haiti + + align:start position:0% +um and and we'll be focusing on Haiti + + + align:start position:0% +um and and we'll be focusing on Haiti +and Rwanda however in each of these + + align:start position:0% +and Rwanda however in each of these + + + align:start position:0% +and Rwanda however in each of these +sites we've tried to use + + align:start position:0% +sites we've tried to use + + + align:start position:0% +sites we've tried to use +um + + align:start position:0% +um + + + align:start position:0% +um +information technology and other + + align:start position:0% +information technology and other + + + align:start position:0% +information technology and other +Technologies to again LeapFrog now + + align:start position:0% +Technologies to again LeapFrog now + + + align:start position:0% +Technologies to again LeapFrog now +that's a lot easier in a place where + + align:start position:0% +that's a lot easier in a place where + + + align:start position:0% +that's a lot easier in a place where +there's stable electricity + + align:start position:0% +there's stable electricity + + + align:start position:0% +there's stable electricity +which is to say a lot of the places we + + align:start position:0% +which is to say a lot of the places we + + + align:start position:0% +which is to say a lot of the places we +work actually do have stable electricity + + align:start position:0% +work actually do have stable electricity + + + align:start position:0% +work actually do have stable electricity +uh Russia the United States + + align:start position:0% +uh Russia the United States + + + align:start position:0% +uh Russia the United States +um or Urban Peru the other sites however + + align:start position:0% +um or Urban Peru the other sites however + + + align:start position:0% +um or Urban Peru the other sites however +have very disrupted electrical supply so + + align:start position:0% +have very disrupted electrical supply so + + + align:start position:0% +have very disrupted electrical supply so +for example Rwanda in 2004 2005 was + + align:start position:0% +for example Rwanda in 2004 2005 was + + + align:start position:0% +for example Rwanda in 2004 2005 was +about five percent on the grid Haiti is + + align:start position:0% +about five percent on the grid Haiti is + + + align:start position:0% +about five percent on the grid Haiti is +a shockingly low number for the Americas + + align:start position:0% +a shockingly low number for the Americas + + + align:start position:0% +a shockingly low number for the Americas +we had a lot of challenges so when I say + + align:start position:0% +we had a lot of challenges so when I say + + + align:start position:0% +we had a lot of challenges so when I say +build systems I literally mean build + + align:start position:0% +build systems I literally mean build + + + align:start position:0% +build systems I literally mean build +systems and this is as simple a diagram + + align:start position:0% +systems and this is as simple a diagram + + + align:start position:0% +systems and this is as simple a diagram +as I could I could come up with + + align:start position:0% +as I could I could come up with + + + align:start position:0% +as I could I could come up with +um as as Hamish said Partners in Health + + align:start position:0% +um as as Hamish said Partners in Health + + + align:start position:0% +um as as Hamish said Partners in Health +is is focused on three he didn't say + + align:start position:0% +is is focused on three he didn't say + + + align:start position:0% +is is focused on three he didn't say +this way but let me say it this way + + align:start position:0% +this way but let me say it this way + + + align:start position:0% +this way but let me say it this way +three levels of care community-based + + align:start position:0% +three levels of care community-based + + + align:start position:0% +three levels of care community-based +care which is done largely with + + align:start position:0% +care which is done largely with + + + align:start position:0% +care which is done largely with +community health workers community + + align:start position:0% +community health workers community + + + align:start position:0% +community health workers community +health workers who we that usually call + + align:start position:0% +health workers who we that usually call + + + align:start position:0% +health workers who we that usually call +accommodernators people who are + + align:start position:0% +accommodernators people who are + + + align:start position:0% +accommodernators people who are +accompanying their neighbors with + + align:start position:0% +accompanying their neighbors with + + + align:start position:0% +accompanying their neighbors with +chronic illness they provide the natural + + align:start position:0% +chronic illness they provide the natural + + + align:start position:0% +chronic illness they provide the natural +human Network to amplify a lot of the + + align:start position:0% +human Network to amplify a lot of the + + + align:start position:0% +human Network to amplify a lot of the +technological innovation that is being + + align:start position:0% +technological innovation that is being + + + align:start position:0% +technological innovation that is being +developed now so if you if you hear + + align:start position:0% +developed now so if you if you hear + + + align:start position:0% +developed now so if you if you hear +about a point of use diagnostic or + + align:start position:0% +about a point of use diagnostic or + + + align:start position:0% +about a point of use diagnostic or +therapeutic + + align:start position:0% +therapeutic + + + align:start position:0% +therapeutic +you know I've heard story after story + + align:start position:0% +you know I've heard story after story + + + align:start position:0% +you know I've heard story after story +about what's coming on the Pike it's + + align:start position:0% +about what's coming on the Pike it's + + + align:start position:0% +about what's coming on the Pike it's +hard to imagine those Technologies being + + align:start position:0% +hard to imagine those Technologies being + + + align:start position:0% +hard to imagine those Technologies being +rolled out effectively equitably + + align:start position:0% +rolled out effectively equitably + + + align:start position:0% +rolled out effectively equitably +especially those most vulnerable and in + + align:start position:0% +especially those most vulnerable and in + + + align:start position:0% +especially those most vulnerable and in +rural regions without community health + + align:start position:0% +rural regions without community health + + + align:start position:0% +rural regions without community health +workers that would be one argument a + + align:start position:0% +workers that would be one argument a + + + align:start position:0% +workers that would be one argument a +second is that the CUNY health workers + + align:start position:0% +second is that the CUNY health workers + + + align:start position:0% +second is that the CUNY health workers +should not be called upon to provide + + align:start position:0% +should not be called upon to provide + + + align:start position:0% +should not be called upon to provide +services that are you know beyond their + + align:start position:0% +services that are you know beyond their + + + align:start position:0% +services that are you know beyond their +or anyone's means for example there is a + + align:start position:0% +or anyone's means for example there is a + + + align:start position:0% +or anyone's means for example there is a +romanticization in international Health + + align:start position:0% +romanticization in international Health + + + align:start position:0% +romanticization in international Health +what used to be called International + + align:start position:0% +what used to be called International + + + align:start position:0% +what used to be called International +Health in the 70s and 80s a + + align:start position:0% +Health in the 70s and 80s a + + + align:start position:0% +Health in the 70s and 80s a +romanticization of the capacity of + + align:start position:0% +romanticization of the capacity of + + + align:start position:0% +romanticization of the capacity of +community health workers to solve + + align:start position:0% +community health workers to solve + + + align:start position:0% +community health workers to solve +problems which is really hidden + + align:start position:0% +problems which is really hidden + + + align:start position:0% +problems which is really hidden +enthusiasm for spending very little + + align:start position:0% +enthusiasm for spending very little + + + align:start position:0% +enthusiasm for spending very little +money in resource poor settings + + align:start position:0% +money in resource poor settings + + + align:start position:0% +money in resource poor settings +and one day people will go back to + + align:start position:0% +and one day people will go back to + + + align:start position:0% +and one day people will go back to +analyze uh you know how this ideology + + align:start position:0% +analyze uh you know how this ideology + + + align:start position:0% +analyze uh you know how this ideology +work but let me give an example when you + + align:start position:0% +work but let me give an example when you + + + align:start position:0% +work but let me give an example when you +hear that traditional birth attendance + + align:start position:0% +hear that traditional birth attendance + + + align:start position:0% +hear that traditional birth attendance +can very much reduce maternal mortality + + align:start position:0% +can very much reduce maternal mortality + + + align:start position:0% +can very much reduce maternal mortality +just skipping the blood banks the + + align:start position:0% +just skipping the blood banks the + + + align:start position:0% +just skipping the blood banks the +cesarean section of modern obstetrics I + + align:start position:0% +cesarean section of modern obstetrics I + + + align:start position:0% +cesarean section of modern obstetrics I +would ask you all to be very suspicious + + align:start position:0% +would ask you all to be very suspicious + + + align:start position:0% +would ask you all to be very suspicious +of such claims because I don't think + + align:start position:0% +of such claims because I don't think + + + align:start position:0% +of such claims because I don't think +there's adequate evidence to prove that + + align:start position:0% +there's adequate evidence to prove that + + + align:start position:0% +there's adequate evidence to prove that +to prove that true so the first thing + + align:start position:0% +to prove that true so the first thing + + + align:start position:0% +to prove that true so the first thing +that we've done in some settings uh is + + align:start position:0% +that we've done in some settings uh is + + + align:start position:0% +that we've done in some settings uh is +to actually build Health Centers now + + align:start position:0% +to actually build Health Centers now + + + align:start position:0% +to actually build Health Centers now +health centers in in the jargon that + + align:start position:0% +health centers in in the jargon that + + + align:start position:0% +health centers in in the jargon that +we're using and developing + + align:start position:0% +we're using and developing + + + align:start position:0% +we're using and developing +are usually nurse-led programs but + + align:start position:0% +are usually nurse-led programs but + + + align:start position:0% +are usually nurse-led programs but +nurses are also rare just as rare in the + + align:start position:0% +nurses are also rare just as rare in the + + + align:start position:0% +nurses are also rare just as rare in the +developing World in rural regions as our + + align:start position:0% +developing World in rural regions as our + + + align:start position:0% +developing World in rural regions as our +doctors + + align:start position:0% +doctors + + + align:start position:0% +doctors +senior managers + + align:start position:0% +senior managers + + + align:start position:0% +senior managers +Etc so that's but that's a often the + + align:start position:0% +Etc so that's but that's a often the + + + align:start position:0% +Etc so that's but that's a often the +first step so it's Health Center + + align:start position:0% +first step so it's Health Center + + + align:start position:0% +first step so it's Health Center +enriched + + align:start position:0% +enriched + + + align:start position:0% +enriched +and then finally some fraction of the + + align:start position:0% +and then finally some fraction of the + + + align:start position:0% +and then finally some fraction of the +care that would be delivered in any of + + align:start position:0% +care that would be delivered in any of + + + align:start position:0% +care that would be delivered in any of +the settings where where Hamish and and + + align:start position:0% +the settings where where Hamish and and + + + align:start position:0% +the settings where where Hamish and and +I and others have worked would be + + align:start position:0% +I and others have worked would be + + + align:start position:0% +I and others have worked would be +incomplete without + + align:start position:0% +incomplete without + + + align:start position:0% +incomplete without +hospitals it just doesn't work that way + + align:start position:0% +hospitals it just doesn't work that way + + + align:start position:0% +hospitals it just doesn't work that way +you know you could manage very + + align:start position:0% +you know you could manage very + + + align:start position:0% +you know you could manage very +effectively I believe you can manage + + align:start position:0% +effectively I believe you can manage + + + align:start position:0% +effectively I believe you can manage +most chronic infectious disease + + align:start position:0% +most chronic infectious disease + + + align:start position:0% +most chronic infectious disease +um and I'll say this in front of Leo and + + align:start position:0% +um and I'll say this in front of Leo and + + + align:start position:0% +um and I'll say this in front of Leo and +see if he buys this most chronic + + align:start position:0% +see if he buys this most chronic + + + align:start position:0% +see if he buys this most chronic +infectious disease I think can be best + + align:start position:0% +infectious disease I think can be best + + + align:start position:0% +infectious disease I think can be best +managed + + align:start position:0% +managed + + + align:start position:0% +managed +in a hospital in a clinic setting or + + align:start position:0% +in a hospital in a clinic setting or + + + align:start position:0% +in a hospital in a clinic setting or +community-based setting + + align:start position:0% +community-based setting + + + align:start position:0% +community-based setting +take HIV disease there's more seats up + + align:start position:0% +take HIV disease there's more seats up + + + align:start position:0% +take HIV disease there's more seats up +here + + align:start position:0% + + + + align:start position:0% + +the the highest standard of care for + + align:start position:0% +the the highest standard of care for + + + align:start position:0% +the the highest standard of care for +AIDS is probably community-based care + + align:start position:0% +AIDS is probably community-based care + + + align:start position:0% +AIDS is probably community-based care +first of all that's the way you deliver + + align:start position:0% +first of all that's the way you deliver + + + align:start position:0% +first of all that's the way you deliver +a therapeutic on a daily basis second of + + align:start position:0% +a therapeutic on a daily basis second of + + + align:start position:0% +a therapeutic on a daily basis second of +all you also are reducing risk of + + align:start position:0% +all you also are reducing risk of + + + align:start position:0% +all you also are reducing risk of +exposure to the leading opportunistic + + align:start position:0% +exposure to the leading opportunistic + + + align:start position:0% +exposure to the leading opportunistic +infection uh killing people with HIV in + + align:start position:0% +infection uh killing people with HIV in + + + align:start position:0% +infection uh killing people with HIV in +the places we work which is tuberculosis + + align:start position:0% +the places we work which is tuberculosis + + + align:start position:0% +the places we work which is tuberculosis +and a lot of that happens at the + + align:start position:0% +and a lot of that happens at the + + + align:start position:0% +and a lot of that happens at the +institutional level so community-based + + align:start position:0% +institutional level so community-based + + + align:start position:0% +institutional level so community-based +care is better in many ways however + + align:start position:0% +care is better in many ways however + + + align:start position:0% +care is better in many ways however +people have complications you know + + align:start position:0% +people have complications you know + + + align:start position:0% +people have complications you know +whether they + + align:start position:0% +whether they + + + align:start position:0% +whether they +you know people have broken bones and + + align:start position:0% +you know people have broken bones and + + + align:start position:0% +you know people have broken bones and +obstructed labor and acute pneumonia and + + align:start position:0% +obstructed labor and acute pneumonia and + + + align:start position:0% +obstructed labor and acute pneumonia and +you know again these and of course + + align:start position:0% +you know again these and of course + + + align:start position:0% +you know again these and of course +any kind of complication of pregnancy + + align:start position:0% +any kind of complication of pregnancy + + + align:start position:0% +any kind of complication of pregnancy +these are really best managed in a + + align:start position:0% +these are really best managed in a + + + align:start position:0% +these are really best managed in a +hospital so this is what I'm talking + + align:start position:0% +hospital so this is what I'm talking + + + align:start position:0% +hospital so this is what I'm talking +about when I'm saying Health System + + align:start position:0% +about when I'm saying Health System + + + align:start position:0% +about when I'm saying Health System +strengthening there are these three uh + + align:start position:0% +strengthening there are these three uh + + + align:start position:0% +strengthening there are these three uh +components again as they say at MIT it's + + align:start position:0% +components again as they say at MIT it's + + + align:start position:0% +components again as they say at MIT it's +not rocket science + + align:start position:0% + + + + align:start position:0% + +in other words we can do this part + + align:start position:0% +in other words we can do this part + + + align:start position:0% +in other words we can do this part +without you guys + + align:start position:0% +without you guys + + + align:start position:0% +without you guys +so there's a lot we can't do without you + + align:start position:0% +so there's a lot we can't do without you + + + align:start position:0% +so there's a lot we can't do without you +guys and I'll show you what I mean first + + align:start position:0% +guys and I'll show you what I mean first + + + align:start position:0% +guys and I'll show you what I mean first +of all uh and the hay majority said this + + align:start position:0% +of all uh and the hay majority said this + + + align:start position:0% +of all uh and the hay majority said this +and I've used these pictures before at + + align:start position:0% +and I've used these pictures before at + + + align:start position:0% +and I've used these pictures before at +MIT + + align:start position:0% +MIT + + + align:start position:0% +MIT +um to actually this is not an unusual uh + + align:start position:0% +um to actually this is not an unusual uh + + + align:start position:0% +um to actually this is not an unusual uh +clinical story it's pretty much the kind + + align:start position:0% +clinical story it's pretty much the kind + + + align:start position:0% +clinical story it's pretty much the kind +of patient I I see all the time young + + align:start position:0% +of patient I I see all the time young + + + align:start position:0% +of patient I I see all the time young +person with HIV disease and another + + align:start position:0% +person with HIV disease and another + + + align:start position:0% +person with HIV disease and another +problem in this case he's got two he's + + align:start position:0% +problem in this case he's got two he's + + + align:start position:0% +problem in this case he's got two he's +got tuberculosis and and uh probably in + + align:start position:0% +got tuberculosis and and uh probably in + + + align:start position:0% +got tuberculosis and and uh probably in +addition and malnutrition just due to + + align:start position:0% +addition and malnutrition just due to + + + align:start position:0% +addition and malnutrition just due to +those wasting consumptive diseases + + align:start position:0% +those wasting consumptive diseases + + + align:start position:0% +those wasting consumptive diseases +um it's hard to tell in settings of food + + align:start position:0% +um it's hard to tell in settings of food + + + align:start position:0% +um it's hard to tell in settings of food +insecurity you know how to a portion + + align:start position:0% +insecurity you know how to a portion + + + align:start position:0% +insecurity you know how to a portion +responsibility for someone's wasting is + + align:start position:0% +responsibility for someone's wasting is + + + align:start position:0% +responsibility for someone's wasting is +it the disease or the lack of ready + + align:start position:0% +it the disease or the lack of ready + + + align:start position:0% +it the disease or the lack of ready +access to food anyway he this this + + align:start position:0% +access to food anyway he this this + + + align:start position:0% +access to food anyway he this this +patient whose name is Joseph who's of + + align:start position:0% +patient whose name is Joseph who's of + + + align:start position:0% +patient whose name is Joseph who's of +course given me permission to use his + + align:start position:0% +course given me permission to use his + + + align:start position:0% +course given me permission to use his +images and to broadcast them across the + + align:start position:0% +images and to broadcast them across the + + + align:start position:0% +images and to broadcast them across the +world I we've already done that when Jim + + align:start position:0% +world I we've already done that when Jim + + + align:start position:0% +world I we've already done that when Jim +Kim who some of you may have heard of + + align:start position:0% +Kim who some of you may have heard of + + + align:start position:0% +Kim who some of you may have heard of +um was at the World Health Organization + + align:start position:0% +um was at the World Health Organization + + + align:start position:0% +um was at the World Health Organization +he said send me pictures before and + + align:start position:0% +he said send me pictures before and + + + align:start position:0% +he said send me pictures before and +after pictures this is before the + + align:start position:0% +after pictures this is before the + + + align:start position:0% +after pictures this is before the +establishment of some of the big AIDS + + align:start position:0% +establishment of some of the big AIDS + + + align:start position:0% +establishment of some of the big AIDS +treatment and integrated prevention and + + align:start position:0% +treatment and integrated prevention and + + + align:start position:0% +treatment and integrated prevention and +Care programs + + align:start position:0% +Care programs + + + align:start position:0% +Care programs +um I sent him these two pictures uh and + + align:start position:0% +um I sent him these two pictures uh and + + + align:start position:0% +um I sent him these two pictures uh and +many other before and after pictures and + + align:start position:0% +many other before and after pictures and + + + align:start position:0% +many other before and after pictures and +he used these doing this glossy brochure + + align:start position:0% +he used these doing this glossy brochure + + + align:start position:0% +he used these doing this glossy brochure +and I said you know I'd like a copy of + + align:start position:0% +and I said you know I'd like a copy of + + + align:start position:0% +and I said you know I'd like a copy of +that for Joseph so I gave it to Joseph + + align:start position:0% +that for Joseph so I gave it to Joseph + + + align:start position:0% +that for Joseph so I gave it to Joseph +and think he would be very impressed + + align:start position:0% +and think he would be very impressed + + + align:start position:0% +and think he would be very impressed +with that and he just looked at and said + + align:start position:0% +with that and he just looked at and said + + + align:start position:0% +with that and he just looked at and said +yeah I'm a star + + align:start position:0% +yeah I'm a star + + + align:start position:0% +yeah I'm a star +uh he later went by the way he later + + align:start position:0% +uh he later went by the way he later + + + align:start position:0% +uh he later went by the way he later +went to one of these giant AIDS meetings + + align:start position:0% +went to one of these giant AIDS meetings + + + align:start position:0% +went to one of these giant AIDS meetings +how many of you have ever been to one of + + align:start position:0% +how many of you have ever been to one of + + + align:start position:0% +how many of you have ever been to one of +these + + align:start position:0% +these + + + align:start position:0% +these +things is beyond there some of you if + + align:start position:0% +things is beyond there some of you if + + + align:start position:0% +things is beyond there some of you if +it's what 10 15 000 people anyway I went + + align:start position:0% +it's what 10 15 000 people anyway I went + + + align:start position:0% +it's what 10 15 000 people anyway I went +to one from + + align:start position:0% +to one from + + + align:start position:0% +to one from +from Rwanda directly to I think it was + + align:start position:0% +from Rwanda directly to I think it was + + + align:start position:0% +from Rwanda directly to I think it was +Toronto it was definitely Canada + + align:start position:0% +Toronto it was definitely Canada + + + align:start position:0% +Toronto it was definitely Canada +all those Canadian cities look alike to + + align:start position:0% +all those Canadian cities look alike to + + + align:start position:0% +all those Canadian cities look alike to +me + + align:start position:0% +me + + + align:start position:0% +me +and uh and he came from Haiti this guy + + align:start position:0% +and uh and he came from Haiti this guy + + + align:start position:0% +and uh and he came from Haiti this guy +and it was uh + + align:start position:0% +and it was uh + + + align:start position:0% +and it was uh +I learned that one of the Cardinal rules + + align:start position:0% +I learned that one of the Cardinal rules + + + align:start position:0% +I learned that one of the Cardinal rules +of the public I learned many when you + + align:start position:0% +of the public I learned many when you + + + align:start position:0% +of the public I learned many when you +take someone from rural Haiti and + + align:start position:0% +take someone from rural Haiti and + + + align:start position:0% +take someone from rural Haiti and +they've not been to a place like Toronto + + align:start position:0% +they've not been to a place like Toronto + + + align:start position:0% +they've not been to a place like Toronto +for you know there are some things that + + align:start position:0% +for you know there are some things that + + + align:start position:0% +for you know there are some things that +I know all about like be careful on the + + align:start position:0% +I know all about like be careful on the + + + align:start position:0% +I know all about like be careful on the +escalators this uh the card for your + + align:start position:0% +escalators this uh the card for your + + + align:start position:0% +escalators this uh the card for your +hotel room door works Etc but I did + + align:start position:0% +hotel room door works Etc but I did + + + align:start position:0% +hotel room door works Etc but I did +learn a one of the important things in + + align:start position:0% +learn a one of the important things in + + + align:start position:0% +learn a one of the important things in +public health that we should all know is + + align:start position:0% +public health that we should all know is + + + align:start position:0% +public health that we should all know is +you just should not give anyone keys to + + align:start position:0% +you just should not give anyone keys to + + + align:start position:0% +you just should not give anyone keys to +the mini bar + + align:start position:0% +the mini bar + + + align:start position:0% +the mini bar +so anyway the of funding has gone up + + align:start position:0% +so anyway the of funding has gone up + + + align:start position:0% +so anyway the of funding has gone up +very substantially as we know this is + + align:start position:0% +very substantially as we know this is + + + align:start position:0% +very substantially as we know this is +vertical funding is that bad that it's + + align:start position:0% +vertical funding is that bad that it's + + + align:start position:0% +vertical funding is that bad that it's +going to be broadcast to Taipei my + + align:start position:0% +going to be broadcast to Taipei my + + + align:start position:0% +going to be broadcast to Taipei my +little jokes + + align:start position:0% + + + + align:start position:0% + +the the amount of funding has gone up in + + align:start position:0% +the the amount of funding has gone up in + + + align:start position:0% +the the amount of funding has gone up in +part as a way of countering a lack of + + align:start position:0% +part as a way of countering a lack of + + + align:start position:0% +part as a way of countering a lack of +really intelligent response uh to a + + align:start position:0% +really intelligent response uh to a + + + align:start position:0% +really intelligent response uh to a +novel epidemic so that's always going to + + align:start position:0% +novel epidemic so that's always going to + + + align:start position:0% +novel epidemic so that's always going to +be the case and I think it's not + + align:start position:0% +be the case and I think it's not + + + align:start position:0% +be the case and I think it's not +unrelated to the question you're asking + + align:start position:0% +unrelated to the question you're asking + + + align:start position:0% +unrelated to the question you're asking +this class how can we use new technology + + align:start position:0% +this class how can we use new technology + + + align:start position:0% +this class how can we use new technology +uh to promote Health Equity but also how + + align:start position:0% +uh to promote Health Equity but also how + + + align:start position:0% +uh to promote Health Equity but also how +do we take on new problems and there was + + align:start position:0% +do we take on new problems and there was + + + align:start position:0% +do we take on new problems and there was +it's not as if we we've ever lived + + align:start position:0% +it's not as if we we've ever lived + + + align:start position:0% +it's not as if we we've ever lived +through the stunning changes that went + + align:start position:0% +through the stunning changes that went + + + align:start position:0% +through the stunning changes that went +occurred at the epidemiologic change + + align:start position:0% +occurred at the epidemiologic change + + + align:start position:0% +occurred at the epidemiologic change +that occurred at the end of the 20th + + align:start position:0% +that occurred at the end of the 20th + + + align:start position:0% +that occurred at the end of the 20th +century where you had the leading + + align:start position:0% +century where you had the leading + + + align:start position:0% +century where you had the leading +infectious killer of adults tuberculosis + + align:start position:0% +infectious killer of adults tuberculosis + + + align:start position:0% +infectious killer of adults tuberculosis +persisting and then joined to another + + align:start position:0% +persisting and then joined to another + + + align:start position:0% +persisting and then joined to another +killer in Synergy which is HIV and it + + align:start position:0% +killer in Synergy which is HIV and it + + + align:start position:0% +killer in Synergy which is HIV and it +surpassed TB as leading infectious clear + + align:start position:0% +surpassed TB as leading infectious clear + + + align:start position:0% +surpassed TB as leading infectious clear +of the adults in the world today young + + align:start position:0% +of the adults in the world today young + + + align:start position:0% +of the adults in the world today young +adults and they were linked together and + + align:start position:0% +adults and they were linked together and + + + align:start position:0% +adults and they were linked together and +they were invading especially southern + + align:start position:0% +they were invading especially southern + + + align:start position:0% +they were invading especially southern +Africa I would say that's where it was I + + align:start position:0% +Africa I would say that's where it was I + + + align:start position:0% +Africa I would say that's where it was I +mean all over the world in every urban + + align:start position:0% +mean all over the world in every urban + + + align:start position:0% +mean all over the world in every urban +area there are huge outbreaks or large + + align:start position:0% +area there are huge outbreaks or large + + + align:start position:0% +area there are huge outbreaks or large +outbreaks of TB and HIV but this burden + + align:start position:0% +outbreaks of TB and HIV but this burden + + + align:start position:0% +outbreaks of TB and HIV but this burden +of disease was especially enormous + + align:start position:0% +of disease was especially enormous + + + align:start position:0% +of disease was especially enormous +southern Africa and at the same time you + + align:start position:0% +southern Africa and at the same time you + + + align:start position:0% +southern Africa and at the same time you +have a third anybody here an + + align:start position:0% +have a third anybody here an + + + align:start position:0% +have a third anybody here an +anthropologist there's actually several + + align:start position:0% +anthropologist there's actually several + + + align:start position:0% +anthropologist there's actually several +anthropologists at MIT + + align:start position:0% +anthropologists at MIT + + + align:start position:0% +anthropologists at MIT +there was a third collision and that was + + align:start position:0% +there was a third collision and that was + + + align:start position:0% +there was a third collision and that was +with a therapeutic regime + + align:start position:0% +with a therapeutic regime + + + align:start position:0% +with a therapeutic regime +like this Collision didn't occur in the + + align:start position:0% +like this Collision didn't occur in the + + + align:start position:0% +like this Collision didn't occur in the +late 19th century but in the late 20th + + align:start position:0% +late 19th century but in the late 20th + + + align:start position:0% +late 19th century but in the late 20th +century so it also meant that for a + + align:start position:0% +century so it also meant that for a + + + align:start position:0% +century so it also meant that for a +while in any case we had to during uh + + align:start position:0% +while in any case we had to during uh + + + align:start position:0% +while in any case we had to during uh +this period of time we had to say well + + align:start position:0% +this period of time we had to say well + + + align:start position:0% +this period of time we had to say well +what do we how do we treat these people + + align:start position:0% +what do we how do we treat these people + + + align:start position:0% +what do we how do we treat these people +and You Heard lots of arguments you know + + align:start position:0% +and You Heard lots of arguments you know + + + align:start position:0% +and You Heard lots of arguments you know +uh that wasn't sustainable or cost + + align:start position:0% +uh that wasn't sustainable or cost + + + align:start position:0% +uh that wasn't sustainable or cost +effective but you really in the end had + + align:start position:0% +effective but you really in the end had + + + align:start position:0% +effective but you really in the end had +three collisions HIV TV and therapeutic + + align:start position:0% +three collisions HIV TV and therapeutic + + + align:start position:0% +three collisions HIV TV and therapeutic +regimes in other words treatment for + + align:start position:0% +regimes in other words treatment for + + + align:start position:0% +regimes in other words treatment for +tuberculosis and HIV which would lead to + + align:start position:0% +tuberculosis and HIV which would lead to + + + align:start position:0% +tuberculosis and HIV which would lead to +more complex problems like drug + + align:start position:0% +more complex problems like drug + + + align:start position:0% +more complex problems like drug +resistant disease + + align:start position:0% +resistant disease + + + align:start position:0% +resistant disease +and then if one of them is Airborne as + + align:start position:0% +and then if one of them is Airborne as + + + align:start position:0% +and then if one of them is Airborne as +is the case with TB and this is a very + + align:start position:0% +is the case with TB and this is a very + + + align:start position:0% +is the case with TB and this is a very +to use the jargon for my field medical + + align:start position:0% +to use the jargon for my field medical + + + align:start position:0% +to use the jargon for my field medical +anthropology this is an incredibly + + align:start position:0% +anthropology this is an incredibly + + + align:start position:0% +anthropology this is an incredibly +biosocially complex set of problems now + + align:start position:0% +biosocially complex set of problems now + + + align:start position:0% +biosocially complex set of problems now +that's not what I'm going to focus on + + align:start position:0% +that's not what I'm going to focus on + + + align:start position:0% +that's not what I'm going to focus on +today I'm just going to say the + + align:start position:0% +today I'm just going to say the + + + align:start position:0% +today I'm just going to say the +platforms that you build to answer those + + align:start position:0% +platforms that you build to answer those + + + align:start position:0% +platforms that you build to answer those +questions that I disposed are the very + + align:start position:0% +questions that I disposed are the very + + + align:start position:0% +questions that I disposed are the very +same ones that need new technologies to + + align:start position:0% +same ones that need new technologies to + + + align:start position:0% +same ones that need new technologies to +promote good outcomes but also just to + + align:start position:0% +promote good outcomes but also just to + + + align:start position:0% +promote good outcomes but also just to +manage you know and I'll show you some + + align:start position:0% +manage you know and I'll show you some + + + align:start position:0% +manage you know and I'll show you some +examples so + + align:start position:0% +examples so + + + align:start position:0% +examples so +um + + align:start position:0% +um + + + align:start position:0% +um +some of you know that um + + align:start position:0% +some of you know that um + + + align:start position:0% +some of you know that um +and I I think uh Leo and others should + + align:start position:0% +and I I think uh Leo and others should + + + align:start position:0% +and I I think uh Leo and others should +be proud of this that a group of Harvard + + align:start position:0% +be proud of this that a group of Harvard + + + align:start position:0% +be proud of this that a group of Harvard +faculty got together I mean people look + + align:start position:0% +faculty got together I mean people look + + + align:start position:0% +faculty got together I mean people look +at this they Harvard consensus statement + + align:start position:0% +at this they Harvard consensus statement + + + align:start position:0% +at this they Harvard consensus statement +is such a thing possible + + align:start position:0% +is such a thing possible + + + align:start position:0% +is such a thing possible +but we got together and not just Harvard + + align:start position:0% +but we got together and not just Harvard + + + align:start position:0% +but we got together and not just Harvard +faculty but Jeff Sachs was here then and + + align:start position:0% +faculty but Jeff Sachs was here then and + + + align:start position:0% +faculty but Jeff Sachs was here then and +a lot of infectious disease doctors uh + + align:start position:0% +a lot of infectious disease doctors uh + + + align:start position:0% +a lot of infectious disease doctors uh +and some economists and public health + + align:start position:0% +and some economists and public health + + + align:start position:0% +and some economists and public health +figures and said you know we really need + + align:start position:0% +figures and said you know we really need + + + align:start position:0% +figures and said you know we really need +to abandon this idea that we have to + + align:start position:0% +to abandon this idea that we have to + + + align:start position:0% +to abandon this idea that we have to +choose between prevention and Care a + + align:start position:0% +choose between prevention and Care a + + + align:start position:0% +choose between prevention and Care a +noxious idea we have to have integrated + + align:start position:0% +noxious idea we have to have integrated + + + align:start position:0% +noxious idea we have to have integrated +prevention and care for HIV and we have + + align:start position:0% +prevention and care for HIV and we have + + + align:start position:0% +prevention and care for HIV and we have +to acknowledge the complexity of the + + align:start position:0% +to acknowledge the complexity of the + + + align:start position:0% +to acknowledge the complexity of the +epidemic so we wrote that together and + + align:start position:0% +epidemic so we wrote that together and + + + align:start position:0% +epidemic so we wrote that together and +and we were really pushing for something + + align:start position:0% +and we were really pushing for something + + + align:start position:0% +and we were really pushing for something +this is a policy piece and we were + + align:start position:0% +this is a policy piece and we were + + + align:start position:0% +this is a policy piece and we were +pushing of course for the creation of + + align:start position:0% +pushing of course for the creation of + + + align:start position:0% +pushing of course for the creation of +multilateral or bilateral programs that + + align:start position:0% +multilateral or bilateral programs that + + + align:start position:0% +multilateral or bilateral programs that +would fund much more ambitious responses + + align:start position:0% +would fund much more ambitious responses + + + align:start position:0% +would fund much more ambitious responses +to these ranking health problems and + + align:start position:0% +to these ranking health problems and + + + align:start position:0% +to these ranking health problems and +those became pepfar and and first the + + align:start position:0% +those became pepfar and and first the + + + align:start position:0% +those became pepfar and and first the +global fund I guess and then that far + + align:start position:0% +global fund I guess and then that far + + + align:start position:0% +global fund I guess and then that far +and then this failure of imagination + + align:start position:0% +and then this failure of imagination + + + align:start position:0% +and then this failure of imagination +which was I believe caused by a + + align:start position:0% +which was I believe caused by a + + + align:start position:0% +which was I believe caused by a +socialization for scarcity was was + + align:start position:0% +socialization for scarcity was was + + + align:start position:0% +socialization for scarcity was was +countered by resources and that that + + align:start position:0% +countered by resources and that that + + + align:start position:0% +countered by resources and that that +opened up the space to build the + + align:start position:0% +opened up the space to build the + + + align:start position:0% +opened up the space to build the +platforms that I'll describe and also + + align:start position:0% +platforms that I'll describe and also + + + align:start position:0% +platforms that I'll describe and also +created an acute need for better + + align:start position:0% +created an acute need for better + + + align:start position:0% +created an acute need for better +management of information and + + align:start position:0% +management of information and + + + align:start position:0% +management of information and +now the I will skip over this I told you + + align:start position:0% +now the I will skip over this I told you + + + align:start position:0% +now the I will skip over this I told you +we talk about accompaniment but we have + + align:start position:0% +we talk about accompaniment but we have + + + align:start position:0% +we talk about accompaniment but we have +good reason to believe that this is the + + align:start position:0% +good reason to believe that this is the + + + align:start position:0% +good reason to believe that this is the +highest standard of care because we've + + align:start position:0% +highest standard of care because we've + + + align:start position:0% +highest standard of care because we've +been taking care of people in so-called + + align:start position:0% +been taking care of people in so-called + + + align:start position:0% +been taking care of people in so-called +resource core settings as you're just + + align:start position:0% +resource core settings as you're just + + + align:start position:0% +resource core settings as you're just +you determining using in this class + + align:start position:0% +you determining using in this class + + + align:start position:0% +you determining using in this class +um who are still a decade later or more + + align:start position:0% +um who are still a decade later or more + + + align:start position:0% +um who are still a decade later or more +doing very well like this is another + + align:start position:0% +doing very well like this is another + + + align:start position:0% +doing very well like this is another +patient of mine first at home dying of + + align:start position:0% +patient of mine first at home dying of + + + align:start position:0% +patient of mine first at home dying of +AIDS and then 10 years later at Sanders + + align:start position:0% +AIDS and then 10 years later at Sanders + + + align:start position:0% +AIDS and then 10 years later at Sanders +Theater at Harvard giving a talk + + align:start position:0% + + + + align:start position:0% + +for a doctor or nurse or Community + + align:start position:0% +for a doctor or nurse or Community + + + align:start position:0% +for a doctor or nurse or Community +Health program as you might imagine or + + align:start position:0% +Health program as you might imagine or + + + align:start position:0% +Health program as you might imagine or +anyone right to have a family member + + align:start position:0% +anyone right to have a family member + + + align:start position:0% +anyone right to have a family member +who comes back from the dead as the + + align:start position:0% +who comes back from the dead as the + + + align:start position:0% +who comes back from the dead as the +nation say it's very gratifying and when + + align:start position:0% +nation say it's very gratifying and when + + + align:start position:0% +nation say it's very gratifying and when +this happens over and over and over + + align:start position:0% +this happens over and over and over + + + align:start position:0% +this happens over and over and over +again you have a lot of satisfaction but + + align:start position:0% +again you have a lot of satisfaction but + + + align:start position:0% +again you have a lot of satisfaction but +you also have a huge challenge of + + align:start position:0% +you also have a huge challenge of + + + align:start position:0% +you also have a huge challenge of +managing uh information and that + + align:start position:0% +managing uh information and that + + + align:start position:0% +managing uh information and that +challenge occurs at each of the three + + align:start position:0% +challenge occurs at each of the three + + + align:start position:0% +challenge occurs at each of the three +levels that I mentioned at the community + + align:start position:0% +levels that I mentioned at the community + + + align:start position:0% +levels that I mentioned at the community +level for the community health worker or + + align:start position:0% +level for the community health worker or + + + align:start position:0% +level for the community health worker or +a company nature at the clinic level + + align:start position:0% +a company nature at the clinic level + + + align:start position:0% +a company nature at the clinic level +where care should be coordinated not in + + align:start position:0% +where care should be coordinated not in + + + align:start position:0% +where care should be coordinated not in +the hospital and then but finally at the + + align:start position:0% +the hospital and then but finally at the + + + align:start position:0% +the hospital and then but finally at the +hospital how do you track people who do + + align:start position:0% +hospital how do you track people who do + + + align:start position:0% +hospital how do you track people who do +have complications and do get sick again + + align:start position:0% +have complications and do get sick again + + + align:start position:0% +have complications and do get sick again +actually this guy later got does can + + align:start position:0% +actually this guy later got does can + + + align:start position:0% +actually this guy later got does can +anyone guess okay he's been treated now + + align:start position:0% +anyone guess okay he's been treated now + + + align:start position:0% +anyone guess okay he's been treated now +for a smear positive TB and for HIV and + + align:start position:0% +for a smear positive TB and for HIV and + + + align:start position:0% +for a smear positive TB and for HIV and +he's doing well what what do you think + + align:start position:0% +he's doing well what what do you think + + + align:start position:0% +he's doing well what what do you think +now the new and deadly the people in + + align:start position:0% +now the new and deadly the people in + + + align:start position:0% +now the new and deadly the people in +southern Africa know this what's the new + + align:start position:0% +southern Africa know this what's the new + + + align:start position:0% +southern Africa know this what's the new +and deadly + + align:start position:0% +and deadly + + + align:start position:0% +and deadly +complication + + align:start position:0% +complication + + + align:start position:0% +complication +MDR so he got MDR + + align:start position:0% +MDR so he got MDR + + + align:start position:0% +MDR so he got MDR +but may I ask who said that yeah so um + + align:start position:0% +but may I ask who said that yeah so um + + + align:start position:0% +but may I ask who said that yeah so um +that's you know in other words we used + + align:start position:0% +that's you know in other words we used + + + align:start position:0% +that's you know in other words we used +to believe + + align:start position:0% +to believe + + + align:start position:0% +to believe +in the 40s and 50s now I personally was + + align:start position:0% +in the 40s and 50s now I personally was + + + align:start position:0% +in the 40s and 50s now I personally was +not around in the 40s so I didn't + + align:start position:0% +not around in the 40s so I didn't + + + align:start position:0% +not around in the 40s so I didn't +personally believe anything in the 40s + + align:start position:0% +personally believe anything in the 40s + + + align:start position:0% +personally believe anything in the 40s +but we used to believe as they say + + align:start position:0% +but we used to believe as they say + + + align:start position:0% +but we used to believe as they say +magisterial magisteri in medicine that + + align:start position:0% +magisterial magisteri in medicine that + + + align:start position:0% +magisterial magisteri in medicine that +you couldn't get tuberculosis twice + + align:start position:0% +you couldn't get tuberculosis twice + + + align:start position:0% +you couldn't get tuberculosis twice +but we didn't have the Diagnostics + + align:start position:0% +but we didn't have the Diagnostics + + + align:start position:0% +but we didn't have the Diagnostics +molecular Diagnostics to show that that + + align:start position:0% +molecular Diagnostics to show that that + + + align:start position:0% +molecular Diagnostics to show that that +was a false idea you can and do get + + align:start position:0% +was a false idea you can and do get + + + align:start position:0% +was a false idea you can and do get +tuberculosis multiple times you can have + + align:start position:0% +tuberculosis multiple times you can have + + + align:start position:0% +tuberculosis multiple times you can have +even have multiple infections at the + + align:start position:0% +even have multiple infections at the + + + align:start position:0% +even have multiple infections at the +same time and then we said well once you + + align:start position:0% +same time and then we said well once you + + + align:start position:0% +same time and then we said well once you +treat someone for the TB + + align:start position:0% +treat someone for the TB + + + align:start position:0% +treat someone for the TB +they're they're good because they have + + align:start position:0% +they're they're good because they have + + + align:start position:0% +they're they're good because they have +natural immunity that also wasn't true + + align:start position:0% +natural immunity that also wasn't true + + + align:start position:0% +natural immunity that also wasn't true +so this problem that Joseph had and + + align:start position:0% +so this problem that Joseph had and + + + align:start position:0% +so this problem that Joseph had and +already survived that is his second bout + + align:start position:0% +already survived that is his second bout + + + align:start position:0% +already survived that is his second bout +with TB MDR TV is going to happen more + + align:start position:0% +with TB MDR TV is going to happen more + + + align:start position:0% +with TB MDR TV is going to happen more +and more and more and so again the + + align:start position:0% +and more and more and so again the + + + align:start position:0% +and more and more and so again the +complexity of this and Hamish mentioned + + align:start position:0% +complexity of this and Hamish mentioned + + + align:start position:0% +complexity of this and Hamish mentioned +some of our work in Peru the complexity + + align:start position:0% +some of our work in Peru the complexity + + + align:start position:0% +some of our work in Peru the complexity +of this is just astounding you have + + align:start position:0% +of this is just astounding you have + + + align:start position:0% +of this is just astounding you have +multiple + + align:start position:0% +multiple + + + align:start position:0% +multiple +drugs you have if you know you're + + align:start position:0% +drugs you have if you know you're + + + align:start position:0% +drugs you have if you know you're +talking sometimes about 10 or 15 drugs a + + align:start position:0% +talking sometimes about 10 or 15 drugs a + + + align:start position:0% +talking sometimes about 10 or 15 drugs a +day you have not as he said thousands of + + align:start position:0% +day you have not as he said thousands of + + + align:start position:0% +day you have not as he said thousands of +patients I'll show you how many tens of + + align:start position:0% +patients I'll show you how many tens of + + + align:start position:0% +patients I'll show you how many tens of +thousands we're talking about and you + + align:start position:0% +thousands we're talking about and you + + + align:start position:0% +thousands we're talking about and you +have to manage uh the the complexity for + + align:start position:0% +have to manage uh the the complexity for + + + align:start position:0% +have to manage uh the the complexity for +every patient but also the complexity of + + align:start position:0% +every patient but also the complexity of + + + align:start position:0% +every patient but also the complexity of +the program + + align:start position:0% +the program + + + align:start position:0% +the program +and + + align:start position:0% +and + + + align:start position:0% +and +and at the same time + + align:start position:0% +and at the same time + + + align:start position:0% +and at the same time +we have to strengthen Health Systems now + + align:start position:0% +we have to strengthen Health Systems now + + + align:start position:0% +we have to strengthen Health Systems now +what does that mean I already told you + + align:start position:0% +what does that mean I already told you + + + align:start position:0% +what does that mean I already told you +that we're getting an influx of vertical + + align:start position:0% +that we're getting an influx of vertical + + + align:start position:0% +that we're getting an influx of vertical +money focused on AIDS but with that + + align:start position:0% +money focused on AIDS but with that + + + align:start position:0% +money focused on AIDS but with that +money we have to make it do several + + align:start position:0% +money we have to make it do several + + + align:start position:0% +money we have to make it do several +things at once one is to strengthen + + align:start position:0% +things at once one is to strengthen + + + align:start position:0% +things at once one is to strengthen +community-based care right but the other + + align:start position:0% +community-based care right but the other + + + align:start position:0% +community-based care right but the other +is to build all those levels those three + + align:start position:0% +is to build all those levels those three + + + align:start position:0% +is to build all those levels those three +levels of of care including hospitals so + + align:start position:0% +levels of of care including hospitals so + + + align:start position:0% +levels of of care including hospitals so +we developed I think along with others + + align:start position:0% +we developed I think along with others + + + align:start position:0% +we developed I think along with others +but this language of Health System + + align:start position:0% +but this language of Health System + + + align:start position:0% +but this language of Health System +strengthening does describe what it is + + align:start position:0% +strengthening does describe what it is + + + align:start position:0% +strengthening does describe what it is +we were doing with the AIDS money we + + align:start position:0% +we were doing with the AIDS money we + + + align:start position:0% +we were doing with the AIDS money we +received in uh especially after 2003 and + + align:start position:0% +received in uh especially after 2003 and + + + align:start position:0% +received in uh especially after 2003 and +this is an example of a place + + align:start position:0% +this is an example of a place + + + align:start position:0% +this is an example of a place +before and after now it is by the way + + align:start position:0% +before and after now it is by the way + + + align:start position:0% +before and after now it is by the way +all uh solar powered as well + + align:start position:0% +all uh solar powered as well + + + align:start position:0% +all uh solar powered as well +and although the the person who + + align:start position:0% +and although the the person who + + + align:start position:0% +and although the the person who +um set up that system in Haitian with us + + align:start position:0% +um set up that system in Haitian with us + + + align:start position:0% +um set up that system in Haitian with us +in Rwanda and elsewhere died in the + + align:start position:0% +in Rwanda and elsewhere died in the + + + align:start position:0% +in Rwanda and elsewhere died in the +earthquake but you know we've made a lot + + align:start position:0% +earthquake but you know we've made a lot + + + align:start position:0% +earthquake but you know we've made a lot +of progress on other leapfrogging + + align:start position:0% +of progress on other leapfrogging + + + align:start position:0% +of progress on other leapfrogging +Technologies including how to power + + align:start position:0% +Technologies including how to power + + + align:start position:0% +Technologies including how to power +these hospitals and we learned how to + + align:start position:0% +these hospitals and we learned how to + + + align:start position:0% +these hospitals and we learned how to +make better hospitals this one was a few + + align:start position:0% +make better hospitals this one was a few + + + align:start position:0% +make better hospitals this one was a few +years later + + align:start position:0% +years later + + + align:start position:0% +years later +um actually a hospital redo in 2003 the + + align:start position:0% +um actually a hospital redo in 2003 the + + + align:start position:0% +um actually a hospital redo in 2003 the +first place that we used Global fund + + align:start position:0% +first place that we used Global fund + + + align:start position:0% +first place that we used Global fund +money this is an 80. + + align:start position:0% +money this is an 80. + + + align:start position:0% +money this is an 80. +um and then we just rebuilt it again + + align:start position:0% +um and then we just rebuilt it again + + + align:start position:0% +um and then we just rebuilt it again +from scratch and I'll talk a little bit + + align:start position:0% +from scratch and I'll talk a little bit + + + align:start position:0% +from scratch and I'll talk a little bit +more about that at the end now this + + align:start position:0% +more about that at the end now this + + + align:start position:0% +more about that at the end now this +model of three levels of intervention + + align:start position:0% +model of three levels of intervention + + + align:start position:0% +model of three levels of intervention +public-private Partnerships you know I + + align:start position:0% +public-private Partnerships you know I + + + align:start position:0% +public-private Partnerships you know I +could I could go on this I don't even + + align:start position:0% +could I could go on this I don't even + + + align:start position:0% +could I could go on this I don't even +know if model is the right word that is + + align:start position:0% +know if model is the right word that is + + + align:start position:0% +know if model is the right word that is +we also want to strengthen wood shell + + align:start position:0% +we also want to strengthen wood shell + + + align:start position:0% +we also want to strengthen wood shell +systems the Public Health Systems + + align:start position:0% +systems the Public Health Systems + + + align:start position:0% +systems the Public Health Systems +because those were the weakest now there + + align:start position:0% +because those were the weakest now there + + + align:start position:0% +because those were the weakest now there +are some places where people are not at + + align:start position:0% +are some places where people are not at + + + align:start position:0% +are some places where people are not at +all sanguine about doing that and are + + align:start position:0% +all sanguine about doing that and are + + + align:start position:0% +all sanguine about doing that and are +going to stick with the private sector + + align:start position:0% +going to stick with the private sector + + + align:start position:0% +going to stick with the private sector +but in general in Latin America and + + align:start position:0% +but in general in Latin America and + + + align:start position:0% +but in general in Latin America and +Africa the places where I work most or + + align:start position:0% +Africa the places where I work most or + + + align:start position:0% +Africa the places where I work most or +to say nothing of Siberia this is a good + + align:start position:0% +to say nothing of Siberia this is a good + + + align:start position:0% +to say nothing of Siberia this is a good +the idea to strengthen the public sector + + align:start position:0% +the idea to strengthen the public sector + + + align:start position:0% +the idea to strengthen the public sector +and in general I'm not saying we have to + + align:start position:0% +and in general I'm not saying we have to + + + align:start position:0% +and in general I'm not saying we have to +be ideological about it is there some + + align:start position:0% +be ideological about it is there some + + + align:start position:0% +be ideological about it is there some +I'm glad I'm getting a weekly update + + align:start position:0% +I'm glad I'm getting a weekly update + + + align:start position:0% +I'm glad I'm getting a weekly update +call on TV I told you Hamish that I love + + align:start position:0% +call on TV I told you Hamish that I love + + + align:start position:0% +call on TV I told you Hamish that I love +technology but not that much + + align:start position:0% + + + + align:start position:0% + +goodbye + + align:start position:0% + + + + align:start position:0% + +as if you were ever on those weekly + + align:start position:0% +as if you were ever on those weekly + + + align:start position:0% +as if you were ever on those weekly +update calls now I'll I'll be ready when + + align:start position:0% +update calls now I'll I'll be ready when + + + align:start position:0% +update calls now I'll I'll be ready when +it comes back so from the Dominican + + align:start position:0% +it comes back so from the Dominican + + + align:start position:0% +it comes back so from the Dominican +border + + align:start position:0% +border + + + align:start position:0% +border +to + + align:start position:0% +to + + + align:start position:0% +to +um to the coast and so many of you have + + align:start position:0% +um to the coast and so many of you have + + + align:start position:0% +um to the coast and so many of you have +been to this this part of the world we + + align:start position:0% +been to this this part of the world we + + + align:start position:0% +been to this this part of the world we +followed this model more or less and + + align:start position:0% +followed this model more or less and + + + align:start position:0% +followed this model more or less and +started serving uh uh a lot of people + + align:start position:0% +started serving uh uh a lot of people + + + align:start position:0% +started serving uh uh a lot of people +how many people well this is this is I + + align:start position:0% +how many people well this is this is I + + + align:start position:0% +how many people well this is this is I +just pulled this yesterday from the PIH + + align:start position:0% +just pulled this yesterday from the PIH + + + align:start position:0% +just pulled this yesterday from the PIH +report annual report + + align:start position:0% +report annual report + + + align:start position:0% +report annual report +um + + align:start position:0% +um + + + align:start position:0% +um +and there's this helpful part the + + align:start position:0% +and there's this helpful part the + + + align:start position:0% +and there's this helpful part the +margins in fact + + align:start position:0% +margins in fact + + + align:start position:0% +margins in fact +whoever made this I didn't I wish I + + align:start position:0% +whoever made this I didn't I wish I + + + align:start position:0% +whoever made this I didn't I wish I +could claim to have made this nice + + align:start position:0% +could claim to have made this nice + + + align:start position:0% +could claim to have made this nice +report but this is very helpful + + align:start position:0% +report but this is very helpful + + + align:start position:0% +report but this is very helpful +certainly helpful when you contemplate + + align:start position:0% +certainly helpful when you contemplate + + + align:start position:0% +certainly helpful when you contemplate +information technology and managing + + align:start position:0% +information technology and managing + + + align:start position:0% +information technology and managing +systems when you start reaching this + + align:start position:0% +systems when you start reaching this + + + align:start position:0% +systems when you start reaching this +scale and this is more patients served + + align:start position:0% +scale and this is more patients served + + + align:start position:0% +scale and this is more patients served +I'm not going to talk about quality of + + align:start position:0% +I'm not going to talk about quality of + + + align:start position:0% +I'm not going to talk about quality of +care today although I believe the + + align:start position:0% +care today although I believe the + + + align:start position:0% +care today although I believe the +programmatic care like creativity is + + align:start position:0% +programmatic care like creativity is + + + align:start position:0% +programmatic care like creativity is +very good as I said but this is many + + align:start position:0% +very good as I said but this is many + + + align:start position:0% +very good as I said but this is many +more probably than the big hospitals in + + align:start position:0% +more probably than the big hospitals in + + + align:start position:0% +more probably than the big hospitals in +Boston where I train Leo train + + align:start position:0% +Boston where I train Leo train + + + align:start position:0% +Boston where I train Leo train +um this is a huge huge scale now you'll + + align:start position:0% +um this is a huge huge scale now you'll + + + align:start position:0% +um this is a huge huge scale now you'll +hear people talk about scale that + + align:start position:0% +hear people talk about scale that + + + align:start position:0% +hear people talk about scale that +involves hundreds of millions of + + align:start position:0% +involves hundreds of millions of + + + align:start position:0% +involves hundreds of millions of +patients and + + align:start position:0% +patients and + + + align:start position:0% +patients and +I'm sure that happens now and again but + + align:start position:0% +I'm sure that happens now and again but + + + align:start position:0% +I'm sure that happens now and again but +it's really we're we're still struggling + + align:start position:0% +it's really we're we're still struggling + + + align:start position:0% +it's really we're we're still struggling +to get there + + align:start position:0% +to get there + + + align:start position:0% +to get there +and I I train some of you were involved + + align:start position:0% +and I I train some of you were involved + + + align:start position:0% +and I I train some of you were involved +in the the uh the creation of the + + align:start position:0% +in the the uh the creation of the + + + align:start position:0% +in the the uh the creation of the +Brigham electronic medical record and + + align:start position:0% +Brigham electronic medical record and + + + align:start position:0% +Brigham electronic medical record and +you know I I was lucky enough to be in + + align:start position:0% +you know I I was lucky enough to be in + + + align:start position:0% +you know I I was lucky enough to be in +that first cohort of American doctors + + align:start position:0% +that first cohort of American doctors + + + align:start position:0% +that first cohort of American doctors +who became accustomed to having + + align:start position:0% +who became accustomed to having + + + align:start position:0% +who became accustomed to having +electronic medical record but the real + + align:start position:0% +electronic medical record but the real + + + align:start position:0% +electronic medical record but the real +the way I got the idea to push this + + align:start position:0% +the way I got the idea to push this + + + align:start position:0% +the way I got the idea to push this +forward in Haiti and to recruit Hamish + + align:start position:0% +forward in Haiti and to recruit Hamish + + + align:start position:0% +forward in Haiti and to recruit Hamish +which I did + + align:start position:0% +which I did + + + align:start position:0% +which I did +was actually getting on board a plane do + + align:start position:0% +was actually getting on board a plane do + + + align:start position:0% +was actually getting on board a plane do +you remember this + + align:start position:0% +you remember this + + + align:start position:0% +you remember this +every time that you go to the American + + align:start position:0% +every time that you go to the American + + + align:start position:0% +every time that you go to the American +Airlines and believe me I have I I would + + align:start position:0% +Airlines and believe me I have I I would + + + align:start position:0% +Airlines and believe me I have I I would +put George Clooney to shame + + align:start position:0% +put George Clooney to shame + + + align:start position:0% +put George Clooney to shame +um they you they can't print out the + + align:start position:0% +um they you they can't print out the + + + align:start position:0% +um they you they can't print out the +boarding pass + + align:start position:0% +boarding pass + + + align:start position:0% +boarding pass +if they don't have the right information + + align:start position:0% +if they don't have the right information + + + align:start position:0% +if they don't have the right information +in in there and it's programmed that + + align:start position:0% +in in there and it's programmed that + + + align:start position:0% +in in there and it's programmed that +they code they wrote or stole I don't + + align:start position:0% +they code they wrote or stole I don't + + + align:start position:0% +they code they wrote or stole I don't +know + + align:start position:0% +know + + + align:start position:0% +know +but this was uh something that American + + align:start position:0% +but this was uh something that American + + + align:start position:0% +but this was uh something that American +Airline used not as open source but they + + align:start position:0% +Airline used not as open source but they + + + align:start position:0% +Airline used not as open source but they +developed their own software you know + + align:start position:0% +developed their own software you know + + + align:start position:0% +developed their own software you know +some of you will know the name of it I + + align:start position:0% +some of you will know the name of it I + + + align:start position:0% +some of you will know the name of it I +certainly remember the name of it and if + + align:start position:0% +certainly remember the name of it and if + + + align:start position:0% +certainly remember the name of it and if +you don't have all the right information + + align:start position:0% +you don't have all the right information + + + align:start position:0% +you don't have all the right information +it won't print the boarding pass how + + align:start position:0% +it won't print the boarding pass how + + + align:start position:0% +it won't print the boarding pass how +many times have you seen this so my + + align:start position:0% +many times have you seen this so my + + + align:start position:0% +many times have you seen this so my +frustration was goading I already told + + align:start position:0% +frustration was goading I already told + + + align:start position:0% +frustration was goading I already told +you I'm a specialist at guilt tripping + + align:start position:0% +you I'm a specialist at guilt tripping + + + align:start position:0% +you I'm a specialist at guilt tripping +but I couldn't manage to Guilt Trip + + align:start position:0% +but I couldn't manage to Guilt Trip + + + align:start position:0% +but I couldn't manage to Guilt Trip +people into making sure that every time + + align:start position:0% +people into making sure that every time + + + align:start position:0% +people into making sure that every time +a patient came in to Clinic they were + + align:start position:0% +a patient came in to Clinic they were + + + align:start position:0% +a patient came in to Clinic they were +weighed does this ring any bells and you + + align:start position:0% +weighed does this ring any bells and you + + + align:start position:0% +weighed does this ring any bells and you +know I thought well that's what doctor + + align:start position:0% +know I thought well that's what doctor + + + align:start position:0% +know I thought well that's what doctor +pay if they don't weigh the patient + + align:start position:0% +pay if they don't weigh the patient + + + align:start position:0% +pay if they don't weigh the patient +although people do that now they call it + + align:start position:0% +although people do that now they call it + + + align:start position:0% +although people do that now they call it +they call that + + align:start position:0% +they call that + + + align:start position:0% +they call that +yeah exactly I just call it you know + + align:start position:0% +yeah exactly I just call it you know + + + align:start position:0% +yeah exactly I just call it you know +good old-fashioned Catholic punishment + + align:start position:0% +good old-fashioned Catholic punishment + + + align:start position:0% +good old-fashioned Catholic punishment +but it didn't it didn't work on a + + align:start position:0% +but it didn't it didn't work on a + + + align:start position:0% +but it didn't it didn't work on a +systems level right let's do it if we're + + align:start position:0% +systems level right let's do it if we're + + + align:start position:0% +systems level right let's do it if we're +going to go around to each clinic and + + align:start position:0% +going to go around to each clinic and + + + align:start position:0% +going to go around to each clinic and +you know try and shame the nurses of + + align:start position:0% +you know try and shame the nurses of + + + align:start position:0% +you know try and shame the nurses of +course not doesn't work but + + align:start position:0% +course not doesn't work but + + + align:start position:0% +course not doesn't work but +um we asked hey Mission Darius to + + align:start position:0% +um we asked hey Mission Darius to + + + align:start position:0% +um we asked hey Mission Darius to +rewrite our code so that you couldn't + + align:start position:0% +rewrite our code so that you couldn't + + + align:start position:0% +rewrite our code so that you couldn't +prescribe if the patient wasn't right it + + align:start position:0% +prescribe if the patient wasn't right it + + + align:start position:0% +prescribe if the patient wasn't right it +would just give you like a message like + + align:start position:0% +would just give you like a message like + + + align:start position:0% +would just give you like a message like +I just got about the TV meeting now this + + align:start position:0% +I just got about the TV meeting now this + + + align:start position:0% +I just got about the TV meeting now this +was quite a while ago before this had + + align:start position:0% +was quite a while ago before this had + + + align:start position:0% +was quite a while ago before this had +ever been seen remember this is an area + + align:start position:0% +ever been seen remember this is an area + + + align:start position:0% +ever been seen remember this is an area +these are areas of the world where + + align:start position:0% +these are areas of the world where + + + align:start position:0% +these are areas of the world where +there's no electricity so we also had to + + align:start position:0% +there's no electricity so we also had to + + + align:start position:0% +there's no electricity so we also had to +generate the electricity put in place a + + align:start position:0% +generate the electricity put in place a + + + align:start position:0% +generate the electricity put in place a +satellite hookup + + align:start position:0% +satellite hookup + + + align:start position:0% +satellite hookup +so that it could be automatic up Uplink + + align:start position:0% +so that it could be automatic up Uplink + + + align:start position:0% +so that it could be automatic up Uplink +of this information + + align:start position:0% +of this information + + + align:start position:0% +of this information +and actually build the hospitals I mean + + align:start position:0% +and actually build the hospitals I mean + + + align:start position:0% +and actually build the hospitals I mean +that's an unusual set of Demands again I + + align:start position:0% +that's an unusual set of Demands again I + + + align:start position:0% +that's an unusual set of Demands again I +just called that building a platform as + + align:start position:0% +just called that building a platform as + + + align:start position:0% +just called that building a platform as +if it were easy if I'm on service at the + + align:start position:0% +if it were easy if I'm on service at the + + + align:start position:0% +if it were easy if I'm on service at the +Brigham as an infectious disease doctor + + align:start position:0% +Brigham as an infectious disease doctor + + + align:start position:0% +Brigham as an infectious disease doctor +and think that a patient should have a + + align:start position:0% +and think that a patient should have a + + + align:start position:0% +and think that a patient should have a +brain biopsy to find out what's going on + + align:start position:0% +brain biopsy to find out what's going on + + + align:start position:0% +brain biopsy to find out what's going on +in some infection or supposed infection + + align:start position:0% +in some infection or supposed infection + + + align:start position:0% +in some infection or supposed infection +then I don't have to build the operating + + align:start position:0% +then I don't have to build the operating + + + align:start position:0% +then I don't have to build the operating +room and put in the electricity at the + + align:start position:0% +room and put in the electricity at the + + + align:start position:0% +room and put in the electricity at the +Brigham it's all done + + align:start position:0% +Brigham it's all done + + + align:start position:0% +Brigham it's all done +I don't have to do the surgery or + + align:start position:0% +I don't have to do the surgery or + + + align:start position:0% +I don't have to do the surgery or +anything like that either but this is + + align:start position:0% +anything like that either but this is + + + align:start position:0% +anything like that either but this is +what I mean by building a platform in a + + align:start position:0% +what I mean by building a platform in a + + + align:start position:0% +what I mean by building a platform in a +rural area now here's + + align:start position:0% +rural area now here's + + + align:start position:0% +rural area now here's +just back to what you're doing in this + + align:start position:0% +just back to what you're doing in this + + + align:start position:0% +just back to what you're doing in this +class we knew way before and again + + align:start position:0% +class we knew way before and again + + + align:start position:0% +class we knew way before and again +thanks to American Airlines and those + + align:start position:0% +thanks to American Airlines and those + + + align:start position:0% +thanks to American Airlines and those +boarding passes + + align:start position:0% +boarding passes + + + align:start position:0% +boarding passes +we knew way before this e helped + + align:start position:0% +we knew way before this e helped + + + align:start position:0% +we knew way before this e helped +uh I'm not going to say craze because I + + align:start position:0% +uh I'm not going to say craze because I + + + align:start position:0% +uh I'm not going to say craze because I +think it would be better if it were a + + align:start position:0% +think it would be better if it were a + + + align:start position:0% +think it would be better if it were a +craze we knew a long time before that + + align:start position:0% +craze we knew a long time before that + + + align:start position:0% +craze we knew a long time before that +that we needed this kind of assistance + + align:start position:0% +that we needed this kind of assistance + + + align:start position:0% +that we needed this kind of assistance +again that's why we recruited Hamish and + + align:start position:0% +again that's why we recruited Hamish and + + + align:start position:0% +again that's why we recruited Hamish and +started a health informatics team and + + align:start position:0% +started a health informatics team and + + + align:start position:0% +started a health informatics team and +then later tried to develop these open + + align:start position:0% +then later tried to develop these open + + + align:start position:0% +then later tried to develop these open +source + + align:start position:0% +source + + + align:start position:0% +source +uh + + align:start position:0% +uh + + + align:start position:0% +uh +uh systems that could manage this kind + + align:start position:0% +uh systems that could manage this kind + + + align:start position:0% +uh systems that could manage this kind +of collect complexity but we also knew + + align:start position:0% +of collect complexity but we also knew + + + align:start position:0% +of collect complexity but we also knew +early on that we there's no way have you + + align:start position:0% +early on that we there's no way have you + + + align:start position:0% +early on that we there's no way have you +ever seen a uh a file room in a hospital + + align:start position:0% +ever seen a uh a file room in a hospital + + + align:start position:0% +ever seen a uh a file room in a hospital +yeah it's pretty sad we still have them + + align:start position:0% +yeah it's pretty sad we still have them + + + align:start position:0% +yeah it's pretty sad we still have them +everywhere that we work the paper files + + align:start position:0% +everywhere that we work the paper files + + + align:start position:0% +everywhere that we work the paper files +which you know if you have seeing + + align:start position:0% +which you know if you have seeing + + + align:start position:0% +which you know if you have seeing +patients with a chronic disease they + + align:start position:0% +patients with a chronic disease they + + + align:start position:0% +patients with a chronic disease they +come back many times right it's not the + + align:start position:0% +come back many times right it's not the + + + align:start position:0% +come back many times right it's not the +same as managing you know a fracture or + + align:start position:0% +same as managing you know a fracture or + + + align:start position:0% +same as managing you know a fracture or +even + + align:start position:0% +even + + + align:start position:0% +even +a childbirth right the patients come + + align:start position:0% +a childbirth right the patients come + + + align:start position:0% +a childbirth right the patients come +back with chronic disease every month + + align:start position:0% +back with chronic disease every month + + + align:start position:0% +back with chronic disease every month +and then you have to do what you have to + + align:start position:0% +and then you have to do what you have to + + + align:start position:0% +and then you have to do what you have to +find their chart + + align:start position:0% +find their chart + + + align:start position:0% +find their chart +and again A lot of people are nodding + + align:start position:0% +and again A lot of people are nodding + + + align:start position:0% +and again A lot of people are nodding +because they've known how how hopelessly + + align:start position:0% +because they've known how how hopelessly + + + align:start position:0% +because they've known how how hopelessly +outdated the system is uh and probably + + align:start position:0% +outdated the system is uh and probably + + + align:start position:0% +outdated the system is uh and probably +was you know a hundred years ago but now + + align:start position:0% +was you know a hundred years ago but now + + + align:start position:0% +was you know a hundred years ago but now +we have Alternatives so that's where + + align:start position:0% +we have Alternatives so that's where + + + align:start position:0% +we have Alternatives so that's where +we're trying to go uh and why we need + + align:start position:0% +we're trying to go uh and why we need + + + align:start position:0% +we're trying to go uh and why we need +more help not unless so now we we took + + align:start position:0% +more help not unless so now we we took + + + align:start position:0% +more help not unless so now we we took +this system this platform to Rwanda + + align:start position:0% +this system this platform to Rwanda + + + align:start position:0% +this system this platform to Rwanda +and also to Malawi this tutu and uh and + + align:start position:0% +and also to Malawi this tutu and uh and + + + align:start position:0% +and also to Malawi this tutu and uh and +through partner organizations to other + + align:start position:0% +through partner organizations to other + + + align:start position:0% +through partner organizations to other +settings but this same model we did with + + align:start position:0% +settings but this same model we did with + + + align:start position:0% +settings but this same model we did with +the Clinton Foundation + + align:start position:0% +the Clinton Foundation + + + align:start position:0% +the Clinton Foundation +um + + align:start position:0% +um + + + align:start position:0% +um +uh what was designed to fill in this + + align:start position:0% +uh what was designed to fill in this + + + align:start position:0% +uh what was designed to fill in this +empty space in rural regions + + align:start position:0% +empty space in rural regions + + + align:start position:0% +empty space in rural regions +and the go arm means Governor Rwanda CF + + align:start position:0% +and the go arm means Governor Rwanda CF + + + align:start position:0% +and the go arm means Governor Rwanda CF +Foundation PIH we are Mo by that time + + align:start position:0% +Foundation PIH we are Mo by that time + + + align:start position:0% +Foundation PIH we are Mo by that time +was to build a local sister organization + + align:start position:0% +was to build a local sister organization + + + align:start position:0% +was to build a local sister organization +so some of you here have worked with the + + align:start position:0% +so some of you here have worked with the + + + align:start position:0% +so some of you here have worked with the +sister organizations whether in Peru or + + align:start position:0% +sister organizations whether in Peru or + + + align:start position:0% +sister organizations whether in Peru or +Haiti or Wonderland that's the idea is + + align:start position:0% +Haiti or Wonderland that's the idea is + + + align:start position:0% +Haiti or Wonderland that's the idea is +You're Building local capacity but by + + align:start position:0% +You're Building local capacity but by + + + align:start position:0% +You're Building local capacity but by +then in 2004 2005 we had one hopes + + align:start position:0% +then in 2004 2005 we had one hopes + + + align:start position:0% +then in 2004 2005 we had one hopes +learned enough about the limitations of + + align:start position:0% +learned enough about the limitations of + + + align:start position:0% +learned enough about the limitations of +our past + + align:start position:0% +our past + + + align:start position:0% +our past +uh platforms and could build new ones + + align:start position:0% +uh platforms and could build new ones + + + align:start position:0% +uh platforms and could build new ones +but that's why actually Hamish and + + align:start position:0% +but that's why actually Hamish and + + + align:start position:0% +but that's why actually Hamish and +Darius and others actually spent a lot + + align:start position:0% +Darius and others actually spent a lot + + + align:start position:0% +Darius and others actually spent a lot +of time moved to Rwanda with us to + + align:start position:0% +of time moved to Rwanda with us to + + + align:start position:0% +of time moved to Rwanda with us to +create the system a little bit more + + align:start position:0% +create the system a little bit more + + + align:start position:0% +create the system a little bit more +rapidly uh than it had happened in Haiti + + align:start position:0% +rapidly uh than it had happened in Haiti + + + align:start position:0% +rapidly uh than it had happened in Haiti +where it happened organically or Peru + + align:start position:0% +where it happened organically or Peru + + + align:start position:0% +where it happened organically or Peru +could we start the right way from the + + align:start position:0% +could we start the right way from the + + + align:start position:0% +could we start the right way from the +beginning now the answer to that is + + align:start position:0% +beginning now the answer to that is + + + align:start position:0% +beginning now the answer to that is +still no we're still not there but we I + + align:start position:0% +still no we're still not there but we I + + + align:start position:0% +still no we're still not there but we I +think we've made a lot of progress and + + align:start position:0% +think we've made a lot of progress and + + + align:start position:0% +think we've made a lot of progress and +I'm hoping that + + align:start position:0% +I'm hoping that + + + align:start position:0% +I'm hoping that +um Hamish and maybe Claire will have + + align:start position:0% +um Hamish and maybe Claire will have + + + align:start position:0% +um Hamish and maybe Claire will have +some ideas too so this is what we did we + + align:start position:0% +some ideas too so this is what we did we + + + align:start position:0% +some ideas too so this is what we did we +went to a rural area and we did the same + + align:start position:0% +went to a rural area and we did the same + + + align:start position:0% +went to a rural area and we did the same +three things we did delivered Services + + align:start position:0% +three things we did delivered Services + + + align:start position:0% +three things we did delivered Services +which are largely Clinical Services we + + align:start position:0% +which are largely Clinical Services we + + + align:start position:0% +which are largely Clinical Services we +train local people capacity building and + + align:start position:0% +train local people capacity building and + + + align:start position:0% +train local people capacity building and +we built the systems again this was + + align:start position:0% +we built the systems again this was + + + align:start position:0% +we built the systems again this was +literally rebuilding infrastructure or + + align:start position:0% +literally rebuilding infrastructure or + + + align:start position:0% +literally rebuilding infrastructure or +building and of course we saw the same + + align:start position:0% +building and of course we saw the same + + + align:start position:0% +building and of course we saw the same +kind of effects on patients as we did in + + align:start position:0% +kind of effects on patients as we did in + + + align:start position:0% +kind of effects on patients as we did in +Haiti or anywhere else you know where + + align:start position:0% +Haiti or anywhere else you know where + + + align:start position:0% +Haiti or anywhere else you know where +you go and actually deliver high quality + + align:start position:0% +you go and actually deliver high quality + + + align:start position:0% +you go and actually deliver high quality +and I say community based care to people + + align:start position:0% +and I say community based care to people + + + align:start position:0% +and I say community based care to people +with chronic wasting diseases you have + + align:start position:0% +with chronic wasting diseases you have + + + align:start position:0% +with chronic wasting diseases you have +the same response and I remember one of + + align:start position:0% +the same response and I remember one of + + + align:start position:0% +the same response and I remember one of +the things that struck me in working in + + align:start position:0% +the things that struck me in working in + + + align:start position:0% +the things that struck me in working in +Africa even as late as 2005 2006 and + + align:start position:0% +Africa even as late as 2005 2006 and + + + align:start position:0% +Africa even as late as 2005 2006 and +again I've mentioned the countries I + + align:start position:0% +again I've mentioned the countries I + + + align:start position:0% +again I've mentioned the countries I +mean is that people often did not were + + align:start position:0% +mean is that people often did not were + + + align:start position:0% +mean is that people often did not were +skeptical that we would see the same + + align:start position:0% +skeptical that we would see the same + + + align:start position:0% +skeptical that we would see the same +results in rural Rwanda as we had in + + align:start position:0% +results in rural Rwanda as we had in + + + align:start position:0% +results in rural Rwanda as we had in +Haiti and that wasn't true of course we + + align:start position:0% +Haiti and that wasn't true of course we + + + align:start position:0% +Haiti and that wasn't true of course we +did see the same results but I + + align:start position:0% +did see the same results but I + + + align:start position:0% +did see the same results but I +understand after many years of hearing + + align:start position:0% +understand after many years of hearing + + + align:start position:0% +understand after many years of hearing +well there's medications but we can't + + align:start position:0% +well there's medications but we can't + + + align:start position:0% +well there's medications but we can't +get them to you it's not cost effective + + align:start position:0% +get them to you it's not cost effective + + + align:start position:0% +get them to you it's not cost effective +it's too complicated they were pretty + + align:start position:0% +it's too complicated they were pretty + + + align:start position:0% +it's too complicated they were pretty +skeptical when we showed up that this + + align:start position:0% +skeptical when we showed up that this + + + align:start position:0% +skeptical when we showed up that this +was actually going to work I was + + align:start position:0% +was actually going to work I was + + + align:start position:0% +was actually going to work I was +actually in a Princeton + + align:start position:0% +actually in a Princeton + + + align:start position:0% +actually in a Princeton +uh in in that year maybe 2004 giving a + + align:start position:0% +uh in in that year maybe 2004 giving a + + + align:start position:0% +uh in in that year maybe 2004 giving a +talk and it was full of very + + align:start position:0% +talk and it was full of very + + + align:start position:0% +talk and it was full of very +self-confident young people I'll tell + + align:start position:0% +self-confident young people I'll tell + + + align:start position:0% +self-confident young people I'll tell +you that + + align:start position:0% +you that + + + align:start position:0% +you that +hopefully you guys are more modest at + + align:start position:0% +hopefully you guys are more modest at + + + align:start position:0% +hopefully you guys are more modest at +MIT as nerds tend to be but anyway so + + align:start position:0% +MIT as nerds tend to be but anyway so + + + align:start position:0% +MIT as nerds tend to be but anyway so +we're in The Deco lab to Taipei I don't + + align:start position:0% +we're in The Deco lab to Taipei I don't + + + align:start position:0% +we're in The Deco lab to Taipei I don't +know if that's good so we're in this big + + align:start position:0% +know if that's good so we're in this big + + + align:start position:0% +know if that's good so we're in this big +Auditorium and someone says oh you're + + align:start position:0% +Auditorium and someone says oh you're + + + align:start position:0% +Auditorium and someone says oh you're +never going to make this model work in + + align:start position:0% +never going to make this model work in + + + align:start position:0% +never going to make this model work in +Rwanda and I said oh really and this is + + align:start position:0% +Rwanda and I said oh really and this is + + + align:start position:0% +Rwanda and I said oh really and this is +someone that looked to me to be all I'm + + align:start position:0% +someone that looked to me to be all I'm + + + align:start position:0% +someone that looked to me to be all I'm +about 22 years old + + align:start position:0% +about 22 years old + + + align:start position:0% +about 22 years old +and I said really why is that and they + + align:start position:0% +and I said really why is that and they + + + align:start position:0% +and I said really why is that and they +said well you know this history of + + align:start position:0% +said well you know this history of + + + align:start position:0% +said well you know this history of +violence and Division and and started he + + align:start position:0% +violence and Division and and started he + + + align:start position:0% +violence and Division and and started he +started with a he of course started + + align:start position:0% +started with a he of course started + + + align:start position:0% +started with a he of course started +naming the different ethnicities and I + + align:start position:0% +naming the different ethnicities and I + + + align:start position:0% +naming the different ethnicities and I +said well we'll see you know we'll see + + align:start position:0% +said well we'll see you know we'll see + + + align:start position:0% +said well we'll see you know we'll see +how it works it actually worked even + + align:start position:0% +how it works it actually worked even + + + align:start position:0% +how it works it actually worked even +better in Rwanda this model of + + align:start position:0% +better in Rwanda this model of + + + align:start position:0% +better in Rwanda this model of +community-based care and linked to + + align:start position:0% +community-based care and linked to + + + align:start position:0% +community-based care and linked to +Health Centers and then on to hospitals + + align:start position:0% +Health Centers and then on to hospitals + + + align:start position:0% +Health Centers and then on to hospitals +this guy I I will my medical colleagues + + align:start position:0% +this guy I I will my medical colleagues + + + align:start position:0% +this guy I I will my medical colleagues +have heard me made this to make this + + align:start position:0% +have heard me made this to make this + + + align:start position:0% +have heard me made this to make this +joke before but I'll try I'm going to do + + align:start position:0% +joke before but I'll try I'm going to do + + + align:start position:0% +joke before but I'll try I'm going to do +it again he goes from looking like + + align:start position:0% +it again he goes from looking like + + + align:start position:0% +it again he goes from looking like +Skeletor to kneading Lipitor so that to + + align:start position:0% +Skeletor to kneading Lipitor so that to + + + align:start position:0% +Skeletor to kneading Lipitor so that to +me is a really successful intervention + + align:start position:0% +me is a really successful intervention + + + align:start position:0% +me is a really successful intervention +but this time around we actually worked + + align:start position:0% +but this time around we actually worked + + + align:start position:0% +but this time around we actually worked +with Hamish and team to try and develop + + align:start position:0% +with Hamish and team to try and develop + + + align:start position:0% +with Hamish and team to try and develop +this from the get-go so I mean I could + + align:start position:0% +this from the get-go so I mean I could + + + align:start position:0% +this from the get-go so I mean I could +be wrong but this is a picture from + + align:start position:0% +be wrong but this is a picture from + + + align:start position:0% +be wrong but this is a picture from +Rwanda right + + align:start position:0% +Rwanda right + + + align:start position:0% +Rwanda right +and uh it is definitely one I can tell + + align:start position:0% +and uh it is definitely one I can tell + + + align:start position:0% +and uh it is definitely one I can tell +by the table actually more than my + + align:start position:0% +by the table actually more than my + + + align:start position:0% +by the table actually more than my +colleague where we put in place for high + + align:start position:0% +colleague where we put in place for high + + + align:start position:0% +colleague where we put in place for high +high-speed internet access + + align:start position:0% +high-speed internet access + + + align:start position:0% +high-speed internet access +and started working on a locally adapted + + align:start position:0% +and started working on a locally adapted + + + align:start position:0% +and started working on a locally adapted +Community electronic medical record + + align:start position:0% +Community electronic medical record + + + align:start position:0% +Community electronic medical record +right then and there now again that was + + align:start position:0% +right then and there now again that was + + + align:start position:0% +right then and there now again that was +how did you put it diplomatically that I + + align:start position:0% +how did you put it diplomatically that I + + + align:start position:0% +how did you put it diplomatically that I +was prodding you or + + align:start position:0% +was prodding you or + + + align:start position:0% +was prodding you or +I was annoying this team + + align:start position:0% +I was annoying this team + + + align:start position:0% +I was annoying this team +thank you because on the program side is + + align:start position:0% +thank you because on the program side is + + + align:start position:0% +thank you because on the program side is +the doctors and nurses do we want to + + align:start position:0% +the doctors and nurses do we want to + + + align:start position:0% +the doctors and nurses do we want to +immediate + + align:start position:0% +immediate + + + align:start position:0% +immediate +not gratification we wanted immediate + + align:start position:0% +not gratification we wanted immediate + + + align:start position:0% +not gratification we wanted immediate +results stock management patient + + align:start position:0% +results stock management patient + + + align:start position:0% +results stock management patient +management it just was because our goal + + align:start position:0% +management it just was because our goal + + + align:start position:0% +management it just was because our goal +in going to Rwanda was take what we'd + + align:start position:0% +in going to Rwanda was take what we'd + + + align:start position:0% +in going to Rwanda was take what we'd +done in 20 years in Haiti and do it in + + align:start position:0% +done in 20 years in Haiti and do it in + + + align:start position:0% +done in 20 years in Haiti and do it in +five in Rwanda + + align:start position:0% +five in Rwanda + + + align:start position:0% +five in Rwanda +that was an explicit goal we didn't + + align:start position:0% +that was an explicit goal we didn't + + + align:start position:0% +that was an explicit goal we didn't +really know much about strategic + + align:start position:0% +really know much about strategic + + + align:start position:0% +really know much about strategic +planning or how to use language like + + align:start position:0% +planning or how to use language like + + + align:start position:0% +planning or how to use language like +that but that's what we said in the + + align:start position:0% +that but that's what we said in the + + + align:start position:0% +that but that's what we said in the +beginning that we would go + + align:start position:0% +beginning that we would go + + + align:start position:0% +beginning that we would go +uh you know somebody out of at the + + align:start position:0% +uh you know somebody out of at the + + + align:start position:0% +uh you know somebody out of at the +business school Sloan how to write a + + align:start position:0% +business school Sloan how to write a + + + align:start position:0% +business school Sloan how to write a +case about this that was our strategy so + + align:start position:0% +case about this that was our strategy so + + + align:start position:0% +case about this that was our strategy so +what's your strategy we wanna the answer + + align:start position:0% +what's your strategy we wanna the answer + + + align:start position:0% +what's your strategy we wanna the answer +was to to go to do what we did in 20 + + align:start position:0% +was to to go to do what we did in 20 + + + align:start position:0% +was to to go to do what we did in 20 +years in Haiti in five years because + + align:start position:0% +years in Haiti in five years because + + + align:start position:0% +years in Haiti in five years because +it's a country that's much more + + align:start position:0% +it's a country that's much more + + + align:start position:0% +it's a country that's much more +organized + + align:start position:0% +organized + + + align:start position:0% +organized +um and this was again not in the 90s + + align:start position:0% +um and this was again not in the 90s + + + align:start position:0% +um and this was again not in the 90s +it's just 2005. and I think uh people on + + align:start position:0% +it's just 2005. and I think uh people on + + + align:start position:0% +it's just 2005. and I think uh people on +the Rwanda team feel that that we have + + align:start position:0% +the Rwanda team feel that that we have + + + align:start position:0% +the Rwanda team feel that that we have +succeeded and we could not have done it + + align:start position:0% +succeeded and we could not have done it + + + align:start position:0% +succeeded and we could not have done it +without struggling with some of these + + align:start position:0% +without struggling with some of these + + + align:start position:0% +without struggling with some of these +uh issues of the you know how to manage + + align:start position:0% +uh issues of the you know how to manage + + + align:start position:0% +uh issues of the you know how to manage +information we also had help expert help + + align:start position:0% +information we also had help expert help + + + align:start position:0% +information we also had help expert help +but we didn't have + + align:start position:0% +but we didn't have + + + align:start position:0% +but we didn't have +uh 20 years ago in Haiti and who were + + align:start position:0% +uh 20 years ago in Haiti and who were + + + align:start position:0% +uh 20 years ago in Haiti and who were +they this is in Rwanda but these are not + + align:start position:0% +they this is in Rwanda but these are not + + + align:start position:0% +they this is in Rwanda but these are not +rwandans these are our Haitian + + align:start position:0% +rwandans these are our Haitian + + + align:start position:0% +rwandans these are our Haitian +colleagues who went with us to Rwanda + + align:start position:0% +colleagues who went with us to Rwanda + + + align:start position:0% +colleagues who went with us to Rwanda +and were very credible mentors for the + + align:start position:0% +and were very credible mentors for the + + + align:start position:0% +and were very credible mentors for the +training that went on + + align:start position:0% +training that went on + + + align:start position:0% +training that went on +so uh some of you made it no Dr Leon has + + align:start position:0% +so uh some of you made it no Dr Leon has + + + align:start position:0% +so uh some of you made it no Dr Leon has +worked with us for 20 years he's a very + + align:start position:0% +worked with us for 20 years he's a very + + + align:start position:0% +worked with us for 20 years he's a very +good teacher of course because he's a + + align:start position:0% +good teacher of course because he's a + + + align:start position:0% +good teacher of course because he's a +teacher as was the entire Haitian team + + align:start position:0% +teacher as was the entire Haitian team + + + align:start position:0% +teacher as was the entire Haitian team +that went there they've actually done + + align:start position:0% +that went there they've actually done + + + align:start position:0% +that went there they've actually done +the work they're not Cruising Into A an + + align:start position:0% +the work they're not Cruising Into A an + + + align:start position:0% +the work they're not Cruising Into A an +urban hotel to you have a two-day long + + align:start position:0% +urban hotel to you have a two-day long + + + align:start position:0% +urban hotel to you have a two-day long +Workshop these are people who went and + + align:start position:0% +Workshop these are people who went and + + + align:start position:0% +Workshop these are people who went and +lived with us + + align:start position:0% +lived with us + + + align:start position:0% +lived with us +uh in Rwanda from Haiti with real + + align:start position:0% +uh in Rwanda from Haiti with real + + + align:start position:0% +uh in Rwanda from Haiti with real +credible experience to share so that + + align:start position:0% +credible experience to share so that + + + align:start position:0% +credible experience to share so that +part went I think quite well + + align:start position:0% +part went I think quite well + + + align:start position:0% +part went I think quite well +um and then finally you have to have a + + align:start position:0% +um and then finally you have to have a + + + align:start position:0% +um and then finally you have to have a +there there you have to be able to + + align:start position:0% +there there you have to be able to + + + align:start position:0% +there there you have to be able to +deliver the resources somewhere that is + + align:start position:0% +deliver the resources somewhere that is + + + align:start position:0% +deliver the resources somewhere that is +not appalling and we were sent to a an + + align:start position:0% +not appalling and we were sent to a an + + + align:start position:0% +not appalling and we were sent to a an +abandoned hospital and again some of you + + align:start position:0% +abandoned hospital and again some of you + + + align:start position:0% +abandoned hospital and again some of you +have been there it looked like you might + + align:start position:0% +have been there it looked like you might + + + align:start position:0% +have been there it looked like you might +imagine looked like it had been + + align:start position:0% +imagine looked like it had been + + + align:start position:0% +imagine looked like it had been +abandoned + + align:start position:0% +abandoned + + + align:start position:0% +abandoned +and we had to rebuild that as well + + align:start position:0% +and we had to rebuild that as well + + + align:start position:0% +and we had to rebuild that as well +although later we found that the best + + align:start position:0% +although later we found that the best + + + align:start position:0% +although later we found that the best +health system design was when we could + + align:start position:0% +health system design was when we could + + + align:start position:0% +health system design was when we could +build from scratch and not have to redo + + align:start position:0% +build from scratch and not have to redo + + + align:start position:0% +build from scratch and not have to redo +yeah + + align:start position:0% + + + + align:start position:0% + +that little cross that's an X + + align:start position:0% +that little cross that's an X + + + align:start position:0% +that little cross that's an X +I thought you were a Scottish I thought + + align:start position:0% +I thought you were a Scottish I thought + + + align:start position:0% +I thought you were a Scottish I thought +you were Scottish + + align:start position:0% +you were Scottish + + + align:start position:0% +you were Scottish +I thought you were going to say + + align:start position:0% +I thought you were going to say + + + align:start position:0% +I thought you were going to say +something constructive too but + + align:start position:0% +something constructive too but + + + align:start position:0% +something constructive too but +so you know and then as the years went + + align:start position:0% +so you know and then as the years went + + + align:start position:0% +so you know and then as the years went +by they were at that time in 2004 there + + align:start position:0% +by they were at that time in 2004 there + + + align:start position:0% +by they were at that time in 2004 there +were four of 30 districts that had no + + align:start position:0% +were four of 30 districts that had no + + + align:start position:0% +were four of 30 districts that had no +District hospitals at all we were + + align:start position:0% +District hospitals at all we were + + + align:start position:0% +District hospitals at all we were +assigned to three of the four at our + + align:start position:0% +assigned to three of the four at our + + + align:start position:0% +assigned to three of the four at our +request + + align:start position:0% +request + + + align:start position:0% +request +he said we'd really rather go to a place + + align:start position:0% +he said we'd really rather go to a place + + + align:start position:0% +he said we'd really rather go to a place +where you know that where there's the + + align:start position:0% +where you know that where there's the + + + align:start position:0% +where you know that where there's the +greatest need but also where you could + + align:start position:0% +greatest need but also where you could + + + align:start position:0% +greatest need but also where you could +show that this is more than possible in + + align:start position:0% +show that this is more than possible in + + + align:start position:0% +show that this is more than possible in +a setting like this again without + + align:start position:0% +a setting like this again without + + + align:start position:0% +a setting like this again without +electricity this this is uh in butara in + + align:start position:0% +electricity this this is uh in butara in + + + align:start position:0% +electricity this this is uh in butara in +the North + + align:start position:0% +the North + + + align:start position:0% +the North +and uh + + align:start position:0% +and uh + + + align:start position:0% +and uh +don't look Hamish ignore the little + + align:start position:0% +don't look Hamish ignore the little + + + align:start position:0% +don't look Hamish ignore the little +beeps and blurbs + + align:start position:0% +beeps and blurbs + + + align:start position:0% +beeps and blurbs +and there's no there was no electricity + + align:start position:0% +and there's no there was no electricity + + + align:start position:0% +and there's no there was no electricity +there either and this is probably about + + align:start position:0% +there either and this is probably about + + + align:start position:0% +there either and this is probably about +400 500 000 people without a hospital so + + align:start position:0% +400 500 000 people without a hospital so + + + align:start position:0% +400 500 000 people without a hospital so +we went into the health center and uh + + align:start position:0% +we went into the health center and uh + + + align:start position:0% +we went into the health center and uh +and transformed it into a hospital with + + align:start position:0% +and transformed it into a hospital with + + + align:start position:0% +and transformed it into a hospital with +the ministry of course + + align:start position:0% +the ministry of course + + + align:start position:0% +the ministry of course +um and then we built another one uh this + + align:start position:0% +um and then we built another one uh this + + + align:start position:0% +um and then we built another one uh this +time to our own specifications some of + + align:start position:0% +time to our own specifications some of + + + align:start position:0% +time to our own specifications some of +you have probably heard from a group + + align:start position:0% +you have probably heard from a group + + + align:start position:0% +you have probably heard from a group +with actually some MIT involvement as + + align:start position:0% +with actually some MIT involvement as + + + align:start position:0% +with actually some MIT involvement as +well called mass at that point this + + align:start position:0% +well called mass at that point this + + + align:start position:0% +well called mass at that point this +group had informed but it's a design + + align:start position:0% +group had informed but it's a design + + + align:start position:0% +group had informed but it's a design +let's see Architects but also some + + align:start position:0% +let's see Architects but also some + + + align:start position:0% +let's see Architects but also some +Engineers who are working on social + + align:start position:0% +Engineers who are working on social + + + align:start position:0% +Engineers who are working on social +justice projects and they were born + + align:start position:0% +justice projects and they were born + + + align:start position:0% +justice projects and they were born +really in the process of if I can say + + align:start position:0% +really in the process of if I can say + + + align:start position:0% +really in the process of if I can say +that I think they say it quite a bit + + align:start position:0% +that I think they say it quite a bit + + + align:start position:0% +that I think they say it quite a bit +they were really born out of doing this + + align:start position:0% +they were really born out of doing this + + + align:start position:0% +they were really born out of doing this +uh work with us Moana and you can see + + align:start position:0% +uh work with us Moana and you can see + + + align:start position:0% +uh work with us Moana and you can see +that looks like I I say that looks like + + align:start position:0% +that looks like I I say that looks like + + + align:start position:0% +that looks like I I say that looks like +a you know artist rendering that's a + + align:start position:0% +a you know artist rendering that's a + + + align:start position:0% +a you know artist rendering that's a +photograph that's what the hospital + + align:start position:0% +photograph that's what the hospital + + + align:start position:0% +photograph that's what the hospital +really looks like it's a very beautiful + + align:start position:0% +really looks like it's a very beautiful + + + align:start position:0% +really looks like it's a very beautiful +Hospital + + align:start position:0% +Hospital + + + align:start position:0% +Hospital +now and just for the data at the bottom + + align:start position:0% +now and just for the data at the bottom + + + align:start position:0% +now and just for the data at the bottom +people ask a lot in fact the last time I + + align:start position:0% +people ask a lot in fact the last time I + + + align:start position:0% +people ask a lot in fact the last time I +gave a talk here at MIT uh I was + + align:start position:0% +gave a talk here at MIT uh I was + + + align:start position:0% +gave a talk here at MIT uh I was +practically assailed with questions + + align:start position:0% +practically assailed with questions + + + align:start position:0% +practically assailed with questions +about sustainability + + align:start position:0% +about sustainability + + + align:start position:0% +about sustainability +and uh I was trying to figure out who + + align:start position:0% +and uh I was trying to figure out who + + + align:start position:0% +and uh I was trying to figure out who +which Professor was responsible for that + + align:start position:0% +which Professor was responsible for that + + + align:start position:0% +which Professor was responsible for that +but couldn't + + align:start position:0% +but couldn't + + + align:start position:0% +but couldn't +you know the idea is that you work in + + align:start position:0% +you know the idea is that you work in + + + align:start position:0% +you know the idea is that you work in +the public sector for a number of + + align:start position:0% +the public sector for a number of + + + align:start position:0% +the public sector for a number of +reasons one as Hamish said referring to + + align:start position:0% +reasons one as Hamish said referring to + + + align:start position:0% +reasons one as Hamish said referring to +some other uh work of of mine which I + + align:start position:0% +some other uh work of of mine which I + + + align:start position:0% +some other uh work of of mine which I +kind of forget about is that when you're + + align:start position:0% +kind of forget about is that when you're + + + align:start position:0% +kind of forget about is that when you're +thinking about a right space model + + align:start position:0% +thinking about a right space model + + + align:start position:0% +thinking about a right space model +who confers the right to something like + + align:start position:0% +who confers the right to something like + + + align:start position:0% +who confers the right to something like +the right to Health Care the right to + + align:start position:0% +the right to Health Care the right to + + + align:start position:0% +the right to Health Care the right to +education to the public sector so + + align:start position:0% +education to the public sector so + + + align:start position:0% +education to the public sector so +working with the public sector has that + + align:start position:0% +working with the public sector has that + + + align:start position:0% +working with the public sector has that +Advantage as well and then getting the + + align:start position:0% +Advantage as well and then getting the + + + align:start position:0% +Advantage as well and then getting the +scale any kind of scale I I believe that + + align:start position:0% +scale any kind of scale I I believe that + + + align:start position:0% +scale any kind of scale I I believe that +the notion of scale as we + + align:start position:0% +the notion of scale as we + + + align:start position:0% +the notion of scale as we +anthropologists would say has been + + align:start position:0% +anthropologists would say has been + + + align:start position:0% +anthropologists would say has been +somewhat fetishized people talk about + + align:start position:0% +somewhat fetishized people talk about + + + align:start position:0% +somewhat fetishized people talk about +scale all the time and you're never + + align:start position:0% +scale all the time and you're never + + + align:start position:0% +scale all the time and you're never +quite sure what they mean at least in + + align:start position:0% +quite sure what they mean at least in + + + align:start position:0% +quite sure what they mean at least in +public health but you know because + + align:start position:0% +public health but you know because + + + align:start position:0% +public health but you know because +they're always having a national scale + + align:start position:0% +they're always having a national scale + + + align:start position:0% +they're always having a national scale +but there are also subunits of the + + align:start position:0% +but there are also subunits of the + + + align:start position:0% +but there are also subunits of the +nation in this case the district that + + align:start position:0% +nation in this case the district that + + + align:start position:0% +nation in this case the district that +are all they're important to work with + + align:start position:0% +are all they're important to work with + + + align:start position:0% +are all they're important to work with +and that's what we've done mostly is + + align:start position:0% +and that's what we've done mostly is + + + align:start position:0% +and that's what we've done mostly is +work the district level so that's the + + align:start position:0% +work the district level so that's the + + + align:start position:0% +work the district level so that's the +model replicated uh with with the same + + align:start position:0% +model replicated uh with with the same + + + align:start position:0% +model replicated uh with with the same +challenges that we'd seen in Haiti and + + align:start position:0% +challenges that we'd seen in Haiti and + + + align:start position:0% +challenges that we'd seen in Haiti and +elsewhere + + align:start position:0% +elsewhere + + + align:start position:0% +elsewhere +but a little bit more of a head start I + + align:start position:0% +but a little bit more of a head start I + + + align:start position:0% +but a little bit more of a head start I +would say and + + align:start position:0% +would say and + + + align:start position:0% +would say and +now let me just give you some outcomes + + align:start position:0% +now let me just give you some outcomes + + + align:start position:0% +now let me just give you some outcomes +and then uh + + align:start position:0% +and then uh + + + align:start position:0% +and then uh +open this up for the discussion + + align:start position:0% +open this up for the discussion + + + align:start position:0% +open this up for the discussion +first of all Rwanda we had bet heavily + + align:start position:0% +first of all Rwanda we had bet heavily + + + align:start position:0% +first of all Rwanda we had bet heavily +as as we decided in 2004 we bet heavily + + align:start position:0% +as as we decided in 2004 we bet heavily + + + align:start position:0% +as as we decided in 2004 we bet heavily +on Rwanda being a good place + + align:start position:0% +on Rwanda being a good place + + + align:start position:0% +on Rwanda being a good place +to bring the scale of rural Health + + align:start position:0% +to bring the scale of rural Health + + + align:start position:0% +to bring the scale of rural Health +Project The Glenn Foundation has been + + align:start position:0% +Project The Glenn Foundation has been + + + align:start position:0% +Project The Glenn Foundation has been +heavily honored pardons in health and + + align:start position:0% +heavily honored pardons in health and + + + align:start position:0% +heavily honored pardons in health and +better and I think we were right because + + align:start position:0% +better and I think we were right because + + + align:start position:0% +better and I think we were right because +at that time I can tell you there wasn't + + align:start position:0% +at that time I can tell you there wasn't + + + align:start position:0% +at that time I can tell you there wasn't +a lot of enthusiasm among some of my + + align:start position:0% +a lot of enthusiasm among some of my + + + align:start position:0% +a lot of enthusiasm among some of my +circles on the rights + + align:start position:0% +circles on the rights + + + align:start position:0% +circles on the rights +side for working there but happily we've + + align:start position:0% +side for working there but happily we've + + + align:start position:0% +side for working there but happily we've +made our own assessment and we said that + + align:start position:0% +made our own assessment and we said that + + + align:start position:0% +made our own assessment and we said that +this would be really Forward Thinking + + align:start position:0% +this would be really Forward Thinking + + + align:start position:0% +this would be really Forward Thinking +people to work with on the district + + align:start position:0% +people to work with on the district + + + align:start position:0% +people to work with on the district +level and on the national level and in + + align:start position:0% +level and on the national level and in + + + align:start position:0% +level and on the national level and in +fact that the director of the national + + align:start position:0% +fact that the director of the national + + + align:start position:0% +fact that the director of the national +AIDS program who has been to speak here + + align:start position:0% +AIDS program who has been to speak here + + + align:start position:0% +AIDS program who has been to speak here +before uh Agnes Ben aguahu + + align:start position:0% +before uh Agnes Ben aguahu + + + align:start position:0% +before uh Agnes Ben aguahu +has since gone from director of the + + align:start position:0% +has since gone from director of the + + + align:start position:0% +has since gone from director of the +national AIDS program to the um the lead + + align:start position:0% +national AIDS program to the um the lead + + + align:start position:0% +national AIDS program to the um the lead +technical position in the ministry to + + align:start position:0% +technical position in the ministry to + + + align:start position:0% +technical position in the ministry to +the minister of health so we've got to + + align:start position:0% +the minister of health so we've got to + + + align:start position:0% +the minister of health so we've got to +grow we've been able to grow with her + + align:start position:0% +grow we've been able to grow with her + + + align:start position:0% +grow we've been able to grow with her +and this is what she's done along with + + align:start position:0% +and this is what she's done along with + + + align:start position:0% +and this is what she's done along with +many as she would be cooked at that I + + align:start position:0% +many as she would be cooked at that I + + + align:start position:0% +many as she would be cooked at that I +don't think has been done anywhere and + + align:start position:0% +don't think has been done anywhere and + + + align:start position:0% +don't think has been done anywhere and +that is universal access almost to + + align:start position:0% +that is universal access almost to + + + align:start position:0% +that is universal access almost to +antiretro viral care and there's a lot + + align:start position:0% +antiretro viral care and there's a lot + + + align:start position:0% +antiretro viral care and there's a lot +of talk in 2004 about whether it's a + + align:start position:0% +of talk in 2004 about whether it's a + + + align:start position:0% +of talk in 2004 about whether it's a +small number of patients in in + + align:start position:0% +small number of patients in in + + + align:start position:0% +small number of patients in in +sub-Saharan getting care but it was more + + align:start position:0% +sub-Saharan getting care but it was more + + + align:start position:0% +sub-Saharan getting care but it was more +like a tiny number than a small number I + + align:start position:0% +like a tiny number than a small number I + + + align:start position:0% +like a tiny number than a small number I +have in all these years of doing this + + align:start position:0% +have in all these years of doing this + + + align:start position:0% +have in all these years of doing this +work I've never seen + + align:start position:0% +work I've never seen + + + align:start position:0% +work I've never seen +someone living in a rural area of Africa + + align:start position:0% +someone living in a rural area of Africa + + + align:start position:0% +someone living in a rural area of Africa +and in poverty + + align:start position:0% +and in poverty + + + align:start position:0% +and in poverty +except for + + align:start position:0% +except for + + + align:start position:0% +except for +sites that have come up with uh pepfar + + align:start position:0% +sites that have come up with uh pepfar + + + align:start position:0% +sites that have come up with uh pepfar +or the global fund I had never seen + + align:start position:0% +or the global fund I had never seen + + + align:start position:0% +or the global fund I had never seen +anybody on care + + align:start position:0% +anybody on care + + + align:start position:0% +anybody on care +I saw people know there's knew their + + align:start position:0% +I saw people know there's knew their + + + align:start position:0% +I saw people know there's knew their +status you know there's CD4 accounts but + + align:start position:0% +status you know there's CD4 accounts but + + + align:start position:0% +status you know there's CD4 accounts but +they weren't getting medicines or if + + align:start position:0% +they weren't getting medicines or if + + + align:start position:0% +they weren't getting medicines or if +they had they had received them only + + align:start position:0% +they had they had received them only + + + align:start position:0% +they had they had received them only +irregularly by paying some astronomical + + align:start position:0% +irregularly by paying some astronomical + + + align:start position:0% +irregularly by paying some astronomical +some for them uh and and so this is a + + align:start position:0% +some for them uh and and so this is a + + + align:start position:0% +some for them uh and and so this is a +huge achievement and Rwanda is not I + + align:start position:0% +huge achievement and Rwanda is not I + + + align:start position:0% +huge achievement and Rwanda is not I +mean it is post-conflict it was very + + align:start position:0% +mean it is post-conflict it was very + + + align:start position:0% +mean it is post-conflict it was very +poor still very poor but it was very + + align:start position:0% +poor still very poor but it was very + + + align:start position:0% +poor still very poor but it was very +poor back then and to go from zero to + + align:start position:0% +poor back then and to go from zero to + + + align:start position:0% +poor back then and to go from zero to +now I think they're up to a hundred + + align:start position:0% +now I think they're up to a hundred + + + align:start position:0% +now I think they're up to a hundred +thousand people that's pretty much + + align:start position:0% +thousand people that's pretty much + + + align:start position:0% +thousand people that's pretty much +complete coverage now they're looking + + align:start position:0% +complete coverage now they're looking + + + align:start position:0% +complete coverage now they're looking +with active case finding for others who + + align:start position:0% +with active case finding for others who + + + align:start position:0% +with active case finding for others who +need care + + align:start position:0% +need care + + + align:start position:0% +need care +I don't want to overstate this but if + + align:start position:0% +I don't want to overstate this but if + + + align:start position:0% +I don't want to overstate this but if +you get to 90 000 you're probably + + align:start position:0% +you get to 90 000 you're probably + + + align:start position:0% +you get to 90 000 you're probably +talking about 85 percent of all people + + align:start position:0% +talking about 85 percent of all people + + + align:start position:0% +talking about 85 percent of all people +living with HIV who need uh who need + + align:start position:0% +living with HIV who need uh who need + + + align:start position:0% +living with HIV who need uh who need +Care acutely on therapy now we have not + + align:start position:0% +Care acutely on therapy now we have not + + + align:start position:0% +Care acutely on therapy now we have not +worked uh in all those sites of course + + align:start position:0% +worked uh in all those sites of course + + + align:start position:0% +worked uh in all those sites of course +Hamish has concerned himself with the + + align:start position:0% +Hamish has concerned himself with the + + + align:start position:0% +Hamish has concerned himself with the +national program as have I I have worked + + align:start position:0% +national program as have I I have worked + + + align:start position:0% +national program as have I I have worked +along with a lot of my colleagues in + + align:start position:0% +along with a lot of my colleagues in + + + align:start position:0% +along with a lot of my colleagues in +three of those four districts without a + + align:start position:0% +three of those four districts without a + + + align:start position:0% +three of those four districts without a +uh without a district hospital but + + align:start position:0% +uh without a district hospital but + + + align:start position:0% +uh without a district hospital but +through the electronic medical record + + align:start position:0% +through the electronic medical record + + + align:start position:0% +through the electronic medical record +through e-health through policy + + align:start position:0% +through e-health through policy + + + align:start position:0% +through e-health through policy +discussion debates and a later a + + align:start position:0% +discussion debates and a later a + + + align:start position:0% +discussion debates and a later a +training center that we built in this + + align:start position:0% +training center that we built in this + + + align:start position:0% +training center that we built in this +rural region the first place we went + + align:start position:0% +rural region the first place we went + + + align:start position:0% +rural region the first place we went +we've also participated we feel in a + + align:start position:0% +we've also participated we feel in a + + + align:start position:0% +we've also participated we feel in a +stunning reversal of Fortune uh in + + align:start position:0% +stunning reversal of Fortune uh in + + + align:start position:0% +stunning reversal of Fortune uh in +Rwanda and let me just give you some + + align:start position:0% +Rwanda and let me just give you some + + + align:start position:0% +Rwanda and let me just give you some +numbers first of all when you integrate + + align:start position:0% +numbers first of all when you integrate + + + align:start position:0% +numbers first of all when you integrate +these programs and this is language from + + align:start position:0% +these programs and this is language from + + + align:start position:0% +these programs and this is language from +Julio Fring the dean of Harvard school + + align:start position:0% +Julio Fring the dean of Harvard school + + + align:start position:0% +Julio Fring the dean of Harvard school +public health who is Minister of health + + align:start position:0% +public health who is Minister of health + + + align:start position:0% +public health who is Minister of health +and in Mexico is actually visited Us in + + align:start position:0% +and in Mexico is actually visited Us in + + + align:start position:0% +and in Mexico is actually visited Us in +Rwanda + + align:start position:0% +Rwanda + + + align:start position:0% +Rwanda +um when you integrate with uh again I + + align:start position:0% +um when you integrate with uh again I + + + align:start position:0% +um when you integrate with uh again I +showed you an AIDS program a vertical + + align:start position:0% +showed you an AIDS program a vertical + + + align:start position:0% +showed you an AIDS program a vertical +program same for a family planning + + align:start position:0% +program same for a family planning + + + align:start position:0% +program same for a family planning +program it would be a vertical program + + align:start position:0% +program it would be a vertical program + + + align:start position:0% +program it would be a vertical program +or a tuberculosis program when you can + + align:start position:0% +or a tuberculosis program when you can + + + align:start position:0% +or a tuberculosis program when you can +integrate that into a health system + + align:start position:0% +integrate that into a health system + + + align:start position:0% +integrate that into a health system +strengthening model + + align:start position:0% +strengthening model + + + align:start position:0% +strengthening model +you can have impacts far beyond you know + + align:start position:0% +you can have impacts far beyond you know + + + align:start position:0% +you can have impacts far beyond you know +what the intervention is designed or the + + align:start position:0% +what the intervention is designed or the + + + align:start position:0% +what the intervention is designed or the +vertical intervention is designed to do + + align:start position:0% +vertical intervention is designed to do + + + align:start position:0% +vertical intervention is designed to do +and that's what I think we see happening + + align:start position:0% +and that's what I think we see happening + + + align:start position:0% +and that's what I think we see happening +in uh in Rwanda so looking at child + + align:start position:0% +in uh in Rwanda so looking at child + + + align:start position:0% +in uh in Rwanda so looking at child +mortality and maternal mortality and + + align:start position:0% +mortality and maternal mortality and + + + align:start position:0% +mortality and maternal mortality and +juvenile mortality this is again a + + align:start position:0% +juvenile mortality this is again a + + + align:start position:0% +juvenile mortality this is again a +stunning reversal on the national level + + align:start position:0% +stunning reversal on the national level + + + align:start position:0% +stunning reversal on the national level +and uh it's actually been wonderful to + + align:start position:0% +and uh it's actually been wonderful to + + + align:start position:0% +and uh it's actually been wonderful to +be part of Rwanda during this time this + + align:start position:0% +be part of Rwanda during this time this + + + align:start position:0% +be part of Rwanda during this time this +past decade because trust me after 1994 + + align:start position:0% +past decade because trust me after 1994 + + + align:start position:0% +past decade because trust me after 1994 +there are a lot of people who are only + + align:start position:0% +there are a lot of people who are only + + + align:start position:0% +there are a lot of people who are only +too happy to write off Rwanda as a + + align:start position:0% +too happy to write off Rwanda as a + + + align:start position:0% +too happy to write off Rwanda as a +chance as a place where recovery could + + align:start position:0% +chance as a place where recovery could + + + align:start position:0% +chance as a place where recovery could +occur and many other maimed States and + + align:start position:0% +occur and many other maimed States and + + + align:start position:0% +occur and many other maimed States and +weak states have still struggled and and + + align:start position:0% +weak states have still struggled and and + + + align:start position:0% +weak states have still struggled and and +I've seen that in Haiti but Rwanda + + align:start position:0% +I've seen that in Haiti but Rwanda + + + align:start position:0% +I've seen that in Haiti but Rwanda +really did turn things around glad to + + align:start position:0% +really did turn things around glad to + + + align:start position:0% +really did turn things around glad to +talk about that + + align:start position:0% +talk about that + + + align:start position:0% +talk about that +we made our contribution there as I said + + align:start position:0% +we made our contribution there as I said + + + align:start position:0% +we made our contribution there as I said +with the ministry and the Clinton + + align:start position:0% +with the ministry and the Clinton + + + align:start position:0% +with the ministry and the Clinton +foundation and many other parties and + + align:start position:0% +foundation and many other parties and + + + align:start position:0% +foundation and many other parties and +then uh set off to other settings + + align:start position:0% +then uh set off to other settings + + + align:start position:0% +then uh set off to other settings +and again rural Africa this is part of + + align:start position:0% +and again rural Africa this is part of + + + align:start position:0% +and again rural Africa this is part of +initiative we called in 2004 there were + + align:start position:0% +initiative we called in 2004 there were + + + align:start position:0% +initiative we called in 2004 there were +a late AIDS initiative that Clinton + + align:start position:0% +a late AIDS initiative that Clinton + + + align:start position:0% +a late AIDS initiative that Clinton +launched that year + + align:start position:0% +launched that year + + + align:start position:0% +launched that year +and it was pretty much the same thing + + align:start position:0% +and it was pretty much the same thing + + + align:start position:0% +and it was pretty much the same thing +now let me close by talking a little bit + + align:start position:0% +now let me close by talking a little bit + + + align:start position:0% +now let me close by talking a little bit +about two things one is conscious + + align:start position:0% +about two things one is conscious + + + align:start position:0% +about two things one is conscious +attempts to + + align:start position:0% +attempts to + + + align:start position:0% +attempts to +tackle this challenge of Information + + align:start position:0% +tackle this challenge of Information + + + align:start position:0% +tackle this challenge of Information +Technology and outsystem striking and + + align:start position:0% +Technology and outsystem striking and + + + align:start position:0% +Technology and outsystem striking and +the other is as you might imagine what + + align:start position:0% +the other is as you might imagine what + + + align:start position:0% +the other is as you might imagine what +is what are some things that we didn't + + align:start position:0% +is what are some things that we didn't + + + align:start position:0% +is what are some things that we didn't +plan for and uh I could I'm not going to + + align:start position:0% +plan for and uh I could I'm not going to + + + align:start position:0% +plan for and uh I could I'm not going to +say couldn't but there are some + + align:start position:0% +say couldn't but there are some + + + align:start position:0% +say couldn't but there are some +contingencies that that happened in + + align:start position:0% +contingencies that that happened in + + + align:start position:0% +contingencies that that happened in +Haiti recently as you all know that we + + align:start position:0% +Haiti recently as you all know that we + + + align:start position:0% +Haiti recently as you all know that we +were unprepared for and uh I'd like to + + align:start position:0% +were unprepared for and uh I'd like to + + + align:start position:0% +were unprepared for and uh I'd like to +open up some of our some reflection on + + align:start position:0% +open up some of our some reflection on + + + align:start position:0% +open up some of our some reflection on +how it could be and can be useful there + + align:start position:0% +how it could be and can be useful there + + + align:start position:0% +how it could be and can be useful there +now we've developed along with many + + align:start position:0% +now we've developed along with many + + + align:start position:0% +now we've developed along with many +partners this ghd online platform which + + align:start position:0% +partners this ghd online platform which + + + align:start position:0% +partners this ghd online platform which +we'd love to make sure it gets improved + + align:start position:0% +we'd love to make sure it gets improved + + + align:start position:0% +we'd love to make sure it gets improved +and used that's another thing about uh + + align:start position:0% +and used that's another thing about uh + + + align:start position:0% +and used that's another thing about uh +we're just saying Hamish and I were + + align:start position:0% +we're just saying Hamish and I were + + + align:start position:0% +we're just saying Hamish and I were +quite skeptical 10 years ago about what + + align:start position:0% +quite skeptical 10 years ago about what + + + align:start position:0% +quite skeptical 10 years ago about what +he used to what he calls telemedicine + + align:start position:0% +he used to what he calls telemedicine + + + align:start position:0% +he used to what he calls telemedicine +and it's just that it was so much + + align:start position:0% +and it's just that it was so much + + + align:start position:0% +and it's just that it was so much +disgust but so little implemented right + + align:start position:0% +disgust but so little implemented right + + + align:start position:0% +disgust but so little implemented right +so you go to the places I work there's + + align:start position:0% +so you go to the places I work there's + + + align:start position:0% +so you go to the places I work there's +no electricity there's certainly not + + align:start position:0% +no electricity there's certainly not + + + align:start position:0% +no electricity there's certainly not +going to be telementin but again you + + align:start position:0% +going to be telementin but again you + + + align:start position:0% +going to be telementin but again you +know now you know we have to revise that + + align:start position:0% +know now you know we have to revise that + + + align:start position:0% +know now you know we have to revise that +because with new technologies including + + align:start position:0% +because with new technologies including + + + align:start position:0% +because with new technologies including +Broadband access and Rural reaches you + + align:start position:0% +Broadband access and Rural reaches you + + + align:start position:0% +Broadband access and Rural reaches you +can imagine a much more robust platform + + align:start position:0% +can imagine a much more robust platform + + + align:start position:0% +can imagine a much more robust platform +to use that much abused word uh in using + + align:start position:0% +to use that much abused word uh in using + + + align:start position:0% +to use that much abused word uh in using +telemedicine but also + + align:start position:0% +telemedicine but also + + + align:start position:0% +telemedicine but also +um this this platform again which should + + align:start position:0% +um this this platform again which should + + + align:start position:0% +um this this platform again which should +be linked to other efforts as you can + + align:start position:0% +be linked to other efforts as you can + + + align:start position:0% +be linked to other efforts as you can +see there's lots of members in a lot of + + align:start position:0% +see there's lots of members in a lot of + + + align:start position:0% +see there's lots of members in a lot of +countries and a lot of them are ngos + + align:start position:0% +countries and a lot of them are ngos + + + align:start position:0% +countries and a lot of them are ngos +hospitals academics + + align:start position:0% +hospitals academics + + + align:start position:0% +hospitals academics +and and this platform is again open + + align:start position:0% +and and this platform is again open + + + align:start position:0% +and and this platform is again open +source this is I bet you I learned that + + align:start position:0% +source this is I bet you I learned that + + + align:start position:0% +source this is I bet you I learned that +term from Hamish and Darius + + align:start position:0% +term from Hamish and Darius + + + align:start position:0% +term from Hamish and Darius +I had no idea what that meant probably + + align:start position:0% +I had no idea what that meant probably + + + align:start position:0% +I had no idea what that meant probably +10 years ago and it was a bit of a you + + align:start position:0% +10 years ago and it was a bit of a you + + + align:start position:0% +10 years ago and it was a bit of a you +know struggle for us I was looking for + + align:start position:0% +know struggle for us I was looking for + + + align:start position:0% +know struggle for us I was looking for +expedience and saying no speed it up + + align:start position:0% +expedience and saying no speed it up + + + align:start position:0% +expedience and saying no speed it up +speed it up + + align:start position:0% +speed it up + + + align:start position:0% +speed it up +um and uh but I think the purists were + + align:start position:0% +um and uh but I think the purists were + + + align:start position:0% +um and uh but I think the purists were +saying the open source part is really + + align:start position:0% +saying the open source part is really + + + align:start position:0% +saying the open source part is really +important if some of this code we will + + align:start position:0% +important if some of this code we will + + + align:start position:0% +important if some of this code we will +take us a long time to rewrite but we + + align:start position:0% +take us a long time to rewrite but we + + + align:start position:0% +take us a long time to rewrite but we +should do it ourselves so that we can + + align:start position:0% +should do it ourselves so that we can + + + align:start position:0% +should do it ourselves so that we can +say this is an open medical record + + align:start position:0% +say this is an open medical record + + + align:start position:0% +say this is an open medical record +system problem and uh so I'll just say + + align:start position:0% +system problem and uh so I'll just say + + + align:start position:0% +system problem and uh so I'll just say +publicly thank you for that teaching + + align:start position:0% +publicly thank you for that teaching + + + align:start position:0% +publicly thank you for that teaching +now the contingencies I want to close + + align:start position:0% +now the contingencies I want to close + + + align:start position:0% +now the contingencies I want to close +with is uh and again Claire Pierre and + + align:start position:0% +with is uh and again Claire Pierre and + + + align:start position:0% +with is uh and again Claire Pierre and +many of you have been nominating to help + + align:start position:0% +many of you have been nominating to help + + + align:start position:0% +many of you have been nominating to help +eclair Pierre actually live through a + + align:start position:0% +eclair Pierre actually live through a + + + align:start position:0% +eclair Pierre actually live through a +lot of this uh with me and and I'm glad + + align:start position:0% +lot of this uh with me and and I'm glad + + + align:start position:0% +lot of this uh with me and and I'm glad +she's here but it was a very uh + + align:start position:0% +she's here but it was a very uh + + + align:start position:0% +she's here but it was a very uh +difficult + + align:start position:0% +difficult + + + align:start position:0% +difficult +time as you might imagine it's after + + align:start position:0% +time as you might imagine it's after + + + align:start position:0% +time as you might imagine it's after +January 10th and this is the uh the + + align:start position:0% +January 10th and this is the uh the + + + align:start position:0% +January 10th and this is the uh the +nursing school the main nursing school + + align:start position:0% +nursing school the main nursing school + + + align:start position:0% +nursing school the main nursing school +and this is 4 53 in the afternoon so + + align:start position:0% +and this is 4 53 in the afternoon so + + + align:start position:0% +and this is 4 53 in the afternoon so +when you think about health system + + align:start position:0% +when you think about health system + + + align:start position:0% +when you think about health system +strengthening there's the three levels I + + align:start position:0% +strengthening there's the three levels I + + + align:start position:0% +strengthening there's the three levels I +talked about community-based Care + + align:start position:0% +talked about community-based Care + + + align:start position:0% +talked about community-based Care +Health Centers and hospitals but there + + align:start position:0% +Health Centers and hospitals but there + + + align:start position:0% +Health Centers and hospitals but there +have to be people in there delivering + + align:start position:0% +have to be people in there delivering + + + align:start position:0% +have to be people in there delivering +services and the loss of a generation uh + + align:start position:0% +services and the loss of a generation uh + + + align:start position:0% +services and the loss of a generation uh +or I mean everybody in the second year + + align:start position:0% +or I mean everybody in the second year + + + align:start position:0% +or I mean everybody in the second year +class perished and their teachers did + + align:start position:0% +class perished and their teachers did + + + align:start position:0% +class perished and their teachers did +too pretty much the laws of a huge + + align:start position:0% +too pretty much the laws of a huge + + + align:start position:0% +too pretty much the laws of a huge +number of health professionals just in + + align:start position:0% +number of health professionals just in + + + align:start position:0% +number of health professionals just in +one day you know again people weren't + + align:start position:0% +one day you know again people weren't + + + align:start position:0% +one day you know again people weren't +prepared for this and rebuilding Haiti + + align:start position:0% +prepared for this and rebuilding Haiti + + + align:start position:0% +prepared for this and rebuilding Haiti +actually means rebuilding it all those + + align:start position:0% +actually means rebuilding it all those + + + align:start position:0% +actually means rebuilding it all those +three levels uh including the tertiary + + align:start position:0% +three levels uh including the tertiary + + + align:start position:0% +three levels uh including the tertiary +Medical Center level + + align:start position:0% +Medical Center level + + + align:start position:0% +Medical Center level +film + + align:start position:0% +film + + + align:start position:0% +film +and then of course I say of course hey + + align:start position:0% +and then of course I say of course hey + + + align:start position:0% +and then of course I say of course hey +the the earthquake was followed + + align:start position:0% +the the earthquake was followed + + + align:start position:0% +the the earthquake was followed +temporarily by A cholerate outbreak + + align:start position:0% +temporarily by A cholerate outbreak + + + align:start position:0% +temporarily by A cholerate outbreak +which you know some people call a + + align:start position:0% +which you know some people call a + + + align:start position:0% +which you know some people call a +secondary Spike immortality but it + + align:start position:0% +secondary Spike immortality but it + + + align:start position:0% +secondary Spike immortality but it +wasn't really related so much the + + align:start position:0% +wasn't really related so much the + + + align:start position:0% +wasn't really related so much the +earthquake as the terribly weak water + + align:start position:0% +earthquake as the terribly weak water + + + align:start position:0% +earthquake as the terribly weak water +system so I'm saying this is a + + align:start position:0% +system so I'm saying this is a + + + align:start position:0% +system so I'm saying this is a +limitation of Health System design + + align:start position:0% +limitation of Health System design + + + align:start position:0% +limitation of Health System design +because it actually occurred and I gave + + align:start position:0% +because it actually occurred and I gave + + + align:start position:0% +because it actually occurred and I gave +a talk about this at MIT last year this + + align:start position:0% +a talk about this at MIT last year this + + + align:start position:0% +a talk about this at MIT last year this +epidemic occurred right in the area + + align:start position:0% +epidemic occurred right in the area + + + align:start position:0% +epidemic occurred right in the area +where we had been working for such a + + align:start position:0% +where we had been working for such a + + + align:start position:0% +where we had been working for such a +long time so it's pretty humbling + + align:start position:0% +long time so it's pretty humbling + + + align:start position:0% +long time so it's pretty humbling +reminder that building Health Systems + + align:start position:0% +reminder that building Health Systems + + + align:start position:0% +reminder that building Health Systems +has to be linked to other systems + + align:start position:0% +has to be linked to other systems + + + align:start position:0% +has to be linked to other systems +water and sanitation education food + + align:start position:0% +water and sanitation education food + + + align:start position:0% +water and sanitation education food +security at the very least shelter I + + align:start position:0% +security at the very least shelter I + + + align:start position:0% +security at the very least shelter I +would throw in there too and of course + + align:start position:0% +would throw in there too and of course + + + align:start position:0% +would throw in there too and of course +why not add jobs + + align:start position:0% +why not add jobs + + + align:start position:0% +why not add jobs +I tried doing that with the global funds + + align:start position:0% +I tried doing that with the global funds + + + align:start position:0% +I tried doing that with the global funds +with Grant I would say oh no we can't + + align:start position:0% +with Grant I would say oh no we can't + + + align:start position:0% +with Grant I would say oh no we can't +have just an AIDS program you have to + + align:start position:0% +have just an AIDS program you have to + + + align:start position:0% +have just an AIDS program you have to +have a women's health program they said + + align:start position:0% +have a women's health program they said + + + align:start position:0% +have a women's health program they said +women's health program this is not the + + align:start position:0% +women's health program this is not the + + + align:start position:0% +women's health program this is not the +global fund for Women's Health that's + + align:start position:0% +global fund for Women's Health that's + + + align:start position:0% +global fund for Women's Health that's +well how are we going to do prevention + + align:start position:0% +well how are we going to do prevention + + + align:start position:0% +well how are we going to do prevention +of mother to child transmission without + + align:start position:0% +of mother to child transmission without + + + align:start position:0% +of mother to child transmission without +thinking about the moms too and don't we + + align:start position:0% +thinking about the moms too and don't we + + + align:start position:0% +thinking about the moms too and don't we +want to promote Family Planning anyway + + align:start position:0% +want to promote Family Planning anyway + + + align:start position:0% +want to promote Family Planning anyway +so I'm kind of a pro at that too + + align:start position:0% +so I'm kind of a pro at that too + + + align:start position:0% +so I'm kind of a pro at that too +broadening the Mandate of others without + + align:start position:0% +broadening the Mandate of others without + + + align:start position:0% +broadening the Mandate of others without +their knowing it + + align:start position:0% + + + + align:start position:0% + +anyway so this is squarely within my + + align:start position:0% +anyway so this is squarely within my + + + align:start position:0% +anyway so this is squarely within my +remed right infectious disease epidemic + + align:start position:0% +remed right infectious disease epidemic + + + align:start position:0% +remed right infectious disease epidemic +and we've been trying and again I'll be + + align:start position:0% +and we've been trying and again I'll be + + + align:start position:0% +and we've been trying and again I'll be +glad to talk about this if anyone's + + align:start position:0% +glad to talk about this if anyone's + + + align:start position:0% +glad to talk about this if anyone's +interested we've been trying to respond + + align:start position:0% +interested we've been trying to respond + + + align:start position:0% +interested we've been trying to respond +obviously with by reinforcing water and + + align:start position:0% +obviously with by reinforcing water and + + + align:start position:0% +obviously with by reinforcing water and +sanitation but we've said wait a second + + align:start position:0% +sanitation but we've said wait a second + + + align:start position:0% +sanitation but we've said wait a second +we've been here a long time and we've + + align:start position:0% +we've been here a long time and we've + + + align:start position:0% +we've been here a long time and we've +failed + + align:start position:0% +failed + + + align:start position:0% +failed +um we don't have a lot of confidence + + align:start position:0% +um we don't have a lot of confidence + + + align:start position:0% +um we don't have a lot of confidence +that it you know a bunch of usaid + + align:start position:0% +that it you know a bunch of usaid + + + align:start position:0% +that it you know a bunch of usaid +contractors are going to come in and + + align:start position:0% +contractors are going to come in and + + + align:start position:0% +contractors are going to come in and +solve all these problems we've been + + align:start position:0% +solve all these problems we've been + + + align:start position:0% +solve all these problems we've been +working here for decades we've heard all + + align:start position:0% +working here for decades we've heard all + + + align:start position:0% +working here for decades we've heard all +this before we have to think of new + + align:start position:0% +this before we have to think of new + + + align:start position:0% +this before we have to think of new +technologies again back to the theme of + + align:start position:0% +technologies again back to the theme of + + + align:start position:0% +technologies again back to the theme of +this course not just to count the number + + align:start position:0% +this course not just to count the number + + + align:start position:0% +this course not just to count the number +of people affected like Jon Snow did but + + align:start position:0% +of people affected like Jon Snow did but + + + align:start position:0% +of people affected like Jon Snow did but +to prevent uh infection as he did by + + align:start position:0% +to prevent uh infection as he did by + + + align:start position:0% +to prevent uh infection as he did by +taking the handle off the Broad Street + + align:start position:0% +taking the handle off the Broad Street + + + align:start position:0% +taking the handle off the Broad Street +Department and so you know I think + + align:start position:0% +Department and so you know I think + + + align:start position:0% +Department and so you know I think +Hamish worked on this I believe others + + align:start position:0% +Hamish worked on this I believe others + + + align:start position:0% +Hamish worked on this I believe others +have as well working with + + align:start position:0% +have as well working with + + + align:start position:0% +have as well working with +um + + align:start position:0% +um + + + align:start position:0% +um +key manager and disaster relief outfits + + align:start position:0% +key manager and disaster relief outfits + + + align:start position:0% +key manager and disaster relief outfits +to try and find out where this epidemic + + align:start position:0% +to try and find out where this epidemic + + + align:start position:0% +to try and find out where this epidemic +was going and uh and to do what was our + + align:start position:0% +was going and uh and to do what was our + + + align:start position:0% +was going and uh and to do what was our +job to do at the very least which was + + align:start position:0% +job to do at the very least which was + + + align:start position:0% +job to do at the very least which was +reduce what's called case fatality rate + + align:start position:0% +reduce what's called case fatality rate + + + align:start position:0% +reduce what's called case fatality rate +the number of people sick who actually + + align:start position:0% +the number of people sick who actually + + + align:start position:0% +the number of people sick who actually +got I'm happy to tell you I think in Mir + + align:start position:0% +got I'm happy to tell you I think in Mir + + + align:start position:0% +got I'm happy to tell you I think in Mir +ballet now which I'm going to return to + + align:start position:0% +ballet now which I'm going to return to + + + align:start position:0% +ballet now which I'm going to return to +him in a second uh I don't think we've + + align:start position:0% +him in a second uh I don't think we've + + + align:start position:0% +him in a second uh I don't think we've +had any cholera deaths recently so we + + align:start position:0% +had any cholera deaths recently so we + + + align:start position:0% +had any cholera deaths recently so we +have a lot of Cholera but the staff + + align:start position:0% +have a lot of Cholera but the staff + + + align:start position:0% +have a lot of Cholera but the staff +there has been trained uh to deliver the + + align:start position:0% +there has been trained uh to deliver the + + + align:start position:0% +there has been trained uh to deliver the +make the diagnosis live with care and + + align:start position:0% +make the diagnosis live with care and + + + align:start position:0% +make the diagnosis live with care and +that's a good thing but it's still not + + align:start position:0% +that's a good thing but it's still not + + + align:start position:0% +that's a good thing but it's still not +going to get rid of Cholera from the + + align:start position:0% +going to get rid of Cholera from the + + + align:start position:0% +going to get rid of Cholera from the +island so we have to do this long-term + + align:start position:0% +island so we have to do this long-term + + + align:start position:0% +island so we have to do this long-term +work + + align:start position:0% +work + + + align:start position:0% +work +um and we also have to I I think I + + align:start position:0% +um and we also have to I I think I + + + align:start position:0% +um and we also have to I I think I +skipped one slide because I didn't want + + align:start position:0% +skipped one slide because I didn't want + + + align:start position:0% +skipped one slide because I didn't want +to go on too long but we've also + + align:start position:0% +to go on too long but we've also + + + align:start position:0% +to go on too long but we've also +launched a an integrated prevention CARE + + align:start position:0% +launched a an integrated prevention CARE + + + align:start position:0% +launched a an integrated prevention CARE +program that includes + + align:start position:0% +program that includes + + + align:start position:0% +program that includes +a vaccination I may have thrown that + + align:start position:0% +a vaccination I may have thrown that + + + align:start position:0% +a vaccination I may have thrown that +thrown that back in but back to this + + align:start position:0% +thrown that back in but back to this + + + align:start position:0% +thrown that back in but back to this +model right again not rocket science + + align:start position:0% +model right again not rocket science + + + align:start position:0% +model right again not rocket science +um I'd argue that you know 20 years from + + align:start position:0% +um I'd argue that you know 20 years from + + + align:start position:0% +um I'd argue that you know 20 years from +now when people are writing books about + + align:start position:0% +now when people are writing books about + + + align:start position:0% +now when people are writing books about +health system striking they'll basically + + align:start position:0% +health system striking they'll basically + + + align:start position:0% +health system striking they'll basically +just describe this community-based Care + + align:start position:0% +just describe this community-based Care + + + align:start position:0% +just describe this community-based Care +on Center enrich Hospital link and + + align:start position:0% +on Center enrich Hospital link and + + + align:start position:0% +on Center enrich Hospital link and +there'll be better language for it new + + align:start position:0% +there'll be better language for it new + + + align:start position:0% +there'll be better language for it new +jargon and hopefully new research posts + + align:start position:0% +jargon and hopefully new research posts + + + align:start position:0% +jargon and hopefully new research posts +and new contracts we usaid but + + align:start position:0% +and new contracts we usaid but + + + align:start position:0% +and new contracts we usaid but +I'm kidding but this is the basic model + + align:start position:0% +I'm kidding but this is the basic model + + + align:start position:0% +I'm kidding but this is the basic model +and again it's not rocket science + + align:start position:0% +and again it's not rocket science + + + align:start position:0% +and again it's not rocket science +now we also considered very strongly + + align:start position:0% +now we also considered very strongly + + + align:start position:0% +now we also considered very strongly +what should be our signal effort post + + align:start position:0% +what should be our signal effort post + + + align:start position:0% +what should be our signal effort post +earthquake in Haiti + + align:start position:0% +earthquake in Haiti + + + align:start position:0% +earthquake in Haiti +and um we were already building yet + + align:start position:0% +and um we were already building yet + + + align:start position:0% +and um we were already building yet +another Community Hospital in this town + + align:start position:0% +another Community Hospital in this town + + + align:start position:0% +another Community Hospital in this town +nearby which I happen to be working in + + align:start position:0% +nearby which I happen to be working in + + + align:start position:0% +nearby which I happen to be working in +in 1983 as in the year between college + + align:start position:0% +in 1983 as in the year between college + + + align:start position:0% +in 1983 as in the year between college +and medical school and so I was pretty + + align:start position:0% +and medical school and so I was pretty + + + align:start position:0% +and medical school and so I was pretty +excited about building a community + + align:start position:0% +excited about building a community + + + align:start position:0% +excited about building a community +hospital in nearby they but after the + + align:start position:0% +hospital in nearby they but after the + + + align:start position:0% +hospital in nearby they but after the +earthquake + + align:start position:0% +earthquake + + + align:start position:0% +earthquake +we went back to the drawing board + + align:start position:0% +we went back to the drawing board + + + align:start position:0% +we went back to the drawing board +literally I say we we this time we took + + align:start position:0% +literally I say we we this time we took + + + align:start position:0% +literally I say we we this time we took +this over to real professionals + + align:start position:0% +this over to real professionals + + + align:start position:0% +this over to real professionals +to redesign the hospital again I said we + + align:start position:0% +to redesign the hospital again I said we + + + align:start position:0% +to redesign the hospital again I said we +had a pretty good community-based design + + align:start position:0% +had a pretty good community-based design + + + align:start position:0% +had a pretty good community-based design +Health Centers we were doing okay + + align:start position:0% +Health Centers we were doing okay + + + align:start position:0% +Health Centers we were doing okay +although I still think a lot of them are + + align:start position:0% +although I still think a lot of them are + + + align:start position:0% +although I still think a lot of them are +dangerous as far as musical infections + + align:start position:0% +dangerous as far as musical infections + + + align:start position:0% +dangerous as far as musical infections +go especially in southern Africa but our + + align:start position:0% +go especially in southern Africa but our + + + align:start position:0% +go especially in southern Africa but our +weak point some of us felt was still the + + align:start position:0% +weak point some of us felt was still the + + + align:start position:0% +weak point some of us felt was still the +quality of the design and construction + + align:start position:0% +quality of the design and construction + + + align:start position:0% +quality of the design and construction +of the hospitals + + align:start position:0% +of the hospitals + + + align:start position:0% +of the hospitals +and then throw on top of that the + + align:start position:0% +and then throw on top of that the + + + align:start position:0% +and then throw on top of that the +earthquake in Haiti and the you know the + + align:start position:0% +earthquake in Haiti and the you know the + + + align:start position:0% +earthquake in Haiti and the you know the +destruction of the medical + + align:start position:0% +destruction of the medical + + + align:start position:0% +destruction of the medical +infrastructure the training + + align:start position:0% +infrastructure the training + + + align:start position:0% +infrastructure the training +infrastructure rather in the capital + + align:start position:0% +infrastructure rather in the capital + + + align:start position:0% +infrastructure rather in the capital +city because that's where all of it was + + align:start position:0% +city because that's where all of it was + + + align:start position:0% +city because that's where all of it was +happening 95 + + align:start position:0% +happening 95 + + + align:start position:0% +happening 95 +and then the loss also of 20 probably of + + align:start position:0% +and then the loss also of 20 probably of + + + align:start position:0% +and then the loss also of 20 probably of +the house Professionals in the + + align:start position:0% +the house Professionals in the + + + align:start position:0% +the house Professionals in the +earthquake of the practicing health + + align:start position:0% +earthquake of the practicing health + + + align:start position:0% +earthquake of the practicing health +professionals + + align:start position:0% +professionals + + + align:start position:0% +professionals +so this is block loss or maiming let's + + align:start position:0% +so this is block loss or maiming let's + + + align:start position:0% +so this is block loss or maiming let's +say so this is a calls for system + + align:start position:0% +say so this is a calls for system + + + align:start position:0% +say so this is a calls for system +redesign right + + align:start position:0% +redesign right + + + align:start position:0% +redesign right +and when President Clinton started + + align:start position:0% +and when President Clinton started + + + align:start position:0% +and when President Clinton started +talking about build back better build + + align:start position:0% +talking about build back better build + + + align:start position:0% +talking about build back better build +back better you know we're asking what + + align:start position:0% +back better you know we're asking what + + + align:start position:0% +back better you know we're asking what +does that mean and we thought this is + + align:start position:0% +does that mean and we thought this is + + + align:start position:0% +does that mean and we thought this is +what it means we're not going to take + + align:start position:0% +what it means we're not going to take + + + align:start position:0% +what it means we're not going to take +shortcuts this time on construction + + align:start position:0% +shortcuts this time on construction + + + align:start position:0% +shortcuts this time on construction +and that means obviously things like + + align:start position:0% +and that means obviously things like + + + align:start position:0% +and that means obviously things like +building code this this hospital was + + align:start position:0% +building code this this hospital was + + + align:start position:0% +building code this this hospital was +designed to California earthquake + + align:start position:0% +designed to California earthquake + + + align:start position:0% +designed to California earthquake +standards and Beyond but also how are we + + align:start position:0% +standards and Beyond but also how are we + + + align:start position:0% +standards and Beyond but also how are we +going to power it if it's going to be a + + align:start position:0% +going to power it if it's going to be a + + + align:start position:0% +going to power it if it's going to be a +medical center rather than a community + + align:start position:0% +medical center rather than a community + + + align:start position:0% +medical center rather than a community +hospital you know we're going to go back + + align:start position:0% +hospital you know we're going to go back + + + align:start position:0% +hospital you know we're going to go back +in and then put in the Solar so we've + + align:start position:0% +in and then put in the Solar so we've + + + align:start position:0% +in and then put in the Solar so we've +been doing that as I mentioned the our + + align:start position:0% +been doing that as I mentioned the our + + + align:start position:0% +been doing that as I mentioned the our +chief partner the implementer died in + + align:start position:0% +chief partner the implementer died in + + + align:start position:0% +chief partner the implementer died in +the earthquake in American but we had we + + align:start position:0% +the earthquake in American but we had we + + + align:start position:0% +the earthquake in American but we had we +knew we had to do something very + + align:start position:0% +knew we had to do something very + + + align:start position:0% +knew we had to do something very +different and so we we redesigned the + + align:start position:0% +different and so we we redesigned the + + + align:start position:0% +different and so we we redesigned the +hospital + + align:start position:0% +hospital + + + align:start position:0% +hospital +and built it I say we I didn't do any + + align:start position:0% +and built it I say we I didn't do any + + + align:start position:0% +and built it I say we I didn't do any +heavy lifting but we've actually managed + + align:start position:0% +heavy lifting but we've actually managed + + + align:start position:0% +heavy lifting but we've actually managed +to get and I hear I always try to make a + + align:start position:0% +to get and I hear I always try to make a + + + align:start position:0% +to get and I hear I always try to make a +tribute to one of my former students uh + + align:start position:0% +tribute to one of my former students uh + + + align:start position:0% +tribute to one of my former students uh +David Walton who is the Project Director + + align:start position:0% +David Walton who is the Project Director + + + align:start position:0% +David Walton who is the Project Director +but also to uh former Construction + + align:start position:0% +but also to uh former Construction + + + align:start position:0% +but also to uh former Construction +Company magnet who started a + + align:start position:0% +Company magnet who started a + + + align:start position:0% +Company magnet who started a +construction company here in + + align:start position:0% +construction company here in + + + align:start position:0% +construction company here in +Massachusetts when he was 22 years old + + align:start position:0% +Massachusetts when he was 22 years old + + + align:start position:0% +Massachusetts when he was 22 years old +his name's Jim and Sarah built a big + + align:start position:0% +his name's Jim and Sarah built a big + + + align:start position:0% +his name's Jim and Sarah built a big +company uh sold it and then since the + + align:start position:0% +company uh sold it and then since the + + + align:start position:0% +company uh sold it and then since the +earthquake has basically been down in + + align:start position:0% +earthquake has basically been down in + + + align:start position:0% +earthquake has basically been down in +Hades and some of you if you ever get to + + align:start position:0% +Hades and some of you if you ever get to + + + align:start position:0% +Hades and some of you if you ever get to +meet him he's a very quiet somewhat + + align:start position:0% +meet him he's a very quiet somewhat + + + align:start position:0% +meet him he's a very quiet somewhat +Gruff but terrific guy + + align:start position:0% +Gruff but terrific guy + + + align:start position:0% +Gruff but terrific guy +and together they put together a team + + align:start position:0% +and together they put together a team + + + align:start position:0% +and together they put together a team +that has people from all over from the + + align:start position:0% +that has people from all over from the + + + align:start position:0% +that has people from all over from the +United States Dominican Republicans + + align:start position:0% +United States Dominican Republicans + + + align:start position:0% +United States Dominican Republicans +especially Haiti and built this really + + align:start position:0% +especially Haiti and built this really + + + align:start position:0% +especially Haiti and built this really +terrific hospital so I'm gonna I'm gonna + + align:start position:0% +terrific hospital so I'm gonna I'm gonna + + + align:start position:0% +terrific hospital so I'm gonna I'm gonna +stop here and open it up for discussion + + align:start position:0% +stop here and open it up for discussion + + + align:start position:0% +stop here and open it up for discussion +with the summary point that there it in + + align:start position:0% +with the summary point that there it in + + + align:start position:0% +with the summary point that there it in +order for you guys and those of you who + + align:start position:0% +order for you guys and those of you who + + + align:start position:0% +order for you guys and those of you who +are interested in technology not all of + + align:start position:0% +are interested in technology not all of + + + align:start position:0% +are interested in technology not all of +you are actually going to generate the + + align:start position:0% +you are actually going to generate the + + + align:start position:0% +you are actually going to generate the +technology but for those who are + + align:start position:0% +technology but for those who are + + + align:start position:0% +technology but for those who are +interested in technology and how it + + align:start position:0% +interested in technology and how it + + + align:start position:0% +interested in technology and how it +works remember that you need it there + + align:start position:0% +works remember that you need it there + + + align:start position:0% +works remember that you need it there +there to a platform that is built and + + align:start position:0% +there to a platform that is built and + + + align:start position:0% +there to a platform that is built and +sometimes that platform is already + + align:start position:0% +sometimes that platform is already + + + align:start position:0% +sometimes that platform is already +halfway there three quarters of the way + + align:start position:0% +halfway there three quarters of the way + + + align:start position:0% +halfway there three quarters of the way +there but sometimes it's almost absent + + align:start position:0% +there but sometimes it's almost absent + + + align:start position:0% +there but sometimes it's almost absent +completely and that's where I hope + + align:start position:0% +completely and that's where I hope + + + align:start position:0% +completely and that's where I hope +people like me come in who are not on + + align:start position:0% +people like me come in who are not on + + + align:start position:0% +people like me come in who are not on +The Cutting Edge in terms of Technology + + align:start position:0% +The Cutting Edge in terms of Technology + + + align:start position:0% +The Cutting Edge in terms of Technology +development or new tools but we're in a + + align:start position:0% +development or new tools but we're in a + + + align:start position:0% +development or new tools but we're in a +way in The Cutting Edge of Delta system + + align:start position:0% +way in The Cutting Edge of Delta system + + + align:start position:0% +way in The Cutting Edge of Delta system +design merely because we're going back + + align:start position:0% +design merely because we're going back + + + align:start position:0% +design merely because we're going back +saying well you can't really skip over + + align:start position:0% +saying well you can't really skip over + + + align:start position:0% +saying well you can't really skip over +that step you actually do have to have + + align:start position:0% +that step you actually do have to have + + + align:start position:0% +that step you actually do have to have +hospitals and health centers and + + align:start position:0% +hospitals and health centers and + + + align:start position:0% +hospitals and health centers and +community health workers so thank you + + align:start position:0% +community health workers so thank you + + + align:start position:0% +community health workers so thank you +very much I look forward + + align:start position:0% + + + + align:start position:0% + +thank you Paul really appreciate it so I + + align:start position:0% +thank you Paul really appreciate it so I + + + align:start position:0% +thank you Paul really appreciate it so I +went over a little bit um we're plenty + + align:start position:0% +went over a little bit um we're plenty + + + align:start position:0% +went over a little bit um we're plenty +of time actually so that's no problem + + align:start position:0% +of time actually so that's no problem + + + align:start position:0% +of time actually so that's no problem +um a couple of things first of all um + + align:start position:0% +um a couple of things first of all um + + + align:start position:0% +um a couple of things first of all um +we'd like to get some questions or + + align:start position:0% +we'd like to get some questions or + + + align:start position:0% +we'd like to get some questions or +comments from the students in the class + + align:start position:0% +comments from the students in the class + + + align:start position:0% +comments from the students in the class +first of all that's all right + + align:start position:0% +first of all that's all right + + + align:start position:0% +first of all that's all right +um and I know you have a few ideas that + + align:start position:0% +um and I know you have a few ideas that + + + align:start position:0% +um and I know you have a few ideas that +you would like to ask Paul about + + align:start position:0% +you would like to ask Paul about + + + align:start position:0% +you would like to ask Paul about +um just a couple of quick comments about + + align:start position:0% +um just a couple of quick comments about + + + align:start position:0% +um just a couple of quick comments about +certain things that we've discussed in + + align:start position:0% +certain things that we've discussed in + + + align:start position:0% +certain things that we've discussed in +the lecture we wanted us about open + + align:start position:0% +the lecture we wanted us about open + + + align:start position:0% +the lecture we wanted us about open +source in addition to making software + + align:start position:0% +source in addition to making software + + + align:start position:0% +source in addition to making software +available to other organizations and + + align:start position:0% +available to other organizations and + + + align:start position:0% +available to other organizations and +countries one of the things that we keep + + align:start position:0% +countries one of the things that we keep + + + align:start position:0% +countries one of the things that we keep +going back to is the fact that there are + + align:start position:0% +going back to is the fact that there are + + + align:start position:0% +going back to is the fact that there are +differences and there are different + + align:start position:0% +differences and there are different + + + align:start position:0% +differences and there are different +requirements and different + + align:start position:0% +requirements and different + + + align:start position:0% +requirements and different +customizations that are required in each + + align:start position:0% +customizations that are required in each + + + align:start position:0% +customizations that are required in each +different country and as the sort of + + align:start position:0% +different country and as the sort of + + + align:start position:0% +different country and as the sort of +provide very little very nature of the + + align:start position:0% +provide very little very nature of the + + + align:start position:0% +provide very little very nature of the +environment you're working by using open + + align:start position:0% +environment you're working by using open + + + align:start position:0% +environment you're working by using open +source we give control and Leadership + + align:start position:0% +source we give control and Leadership + + + align:start position:0% +source we give control and Leadership +and ability to actually manage this + + align:start position:0% +and ability to actually manage this + + + align:start position:0% +and ability to actually manage this +project to people working in different + + align:start position:0% +project to people working in different + + + align:start position:0% +project to people working in different +countries and that's particularly true + + align:start position:0% +countries and that's particularly true + + + align:start position:0% +countries and that's particularly true +in Rwanda where we've trained other + + align:start position:0% +in Rwanda where we've trained other + + + align:start position:0% +in Rwanda where we've trained other +people who around with program + + align:start position:0% +people who around with program + + + align:start position:0% +people who around with program +assistance so I think in addition to the + + align:start position:0% +assistance so I think in addition to the + + + align:start position:0% +assistance so I think in addition to the +kind of + + align:start position:0% +kind of + + + align:start position:0% +kind of +um almost like you know human rights + + align:start position:0% +um almost like you know human rights + + + align:start position:0% +um almost like you know human rights +approach of making these Technologies + + align:start position:0% +approach of making these Technologies + + + align:start position:0% +approach of making these Technologies +available and really empowering people + + align:start position:0% +available and really empowering people + + + align:start position:0% +available and really empowering people +it's also really essential to allow them + + align:start position:0% +it's also really essential to allow them + + + align:start position:0% +it's also really essential to allow them +to be adapted to the real needs on the + + align:start position:0% +to be adapted to the real needs on the + + + align:start position:0% +to be adapted to the real needs on the +ground rather than something that looks + + align:start position:0% +ground rather than something that looks + + + align:start position:0% +ground rather than something that looks +similar such as you know the + + align:start position:0% +similar such as you know the + + + align:start position:0% +similar such as you know the +requirements of hating Rwanda which are + + align:start position:0% +requirements of hating Rwanda which are + + + align:start position:0% +requirements of hating Rwanda which are +superficious and there are many things + + align:start position:0% +superficious and there are many things + + + align:start position:0% +superficious and there are many things +are the same but actually are not quite + + align:start position:0% +are the same but actually are not quite + + + align:start position:0% +are the same but actually are not quite +the same and the other comment I just + + align:start position:0% +the same and the other comment I just + + + align:start position:0% +the same and the other comment I just +make about the collar outbreak that I + + align:start position:0% +make about the collar outbreak that I + + + align:start position:0% +make about the collar outbreak that I +know that there's many people in the MIT + + align:start position:0% +know that there's many people in the MIT + + + align:start position:0% +know that there's many people in the MIT +and the Boston Community who've been + + align:start position:0% +and the Boston Community who've been + + + align:start position:0% +and the Boston Community who've been +looking at the question of how do we + + align:start position:0% +looking at the question of how do we + + + align:start position:0% +looking at the question of how do we +actually understand and measure what's + + align:start position:0% +actually understand and measure what's + + + align:start position:0% +actually understand and measure what's +going on there and so Paul commented + + align:start position:0% +going on there and so Paul commented + + + align:start position:0% +going on there and so Paul commented +about some of these issues and you know + + align:start position:0% +about some of these issues and you know + + + align:start position:0% +about some of these issues and you know +in one of the slides and I know that + + align:start position:0% +in one of the slides and I know that + + + align:start position:0% +in one of the slides and I know that +many people here have been interested in + + align:start position:0% +many people here have been interested in + + + align:start position:0% +many people here have been interested in +that question and they've been looking + + align:start position:0% +that question and they've been looking + + + align:start position:0% +that question and they've been looking +at a whole range of different ways that + + align:start position:0% +at a whole range of different ways that + + + align:start position:0% +at a whole range of different ways that +we can look at the + + align:start position:0% +we can look at the + + + align:start position:0% +we can look at the +um what's going on which communities + + align:start position:0% +um what's going on which communities + + + align:start position:0% +um what's going on which communities +have good Water Supplies how can we even + + align:start position:0% +have good Water Supplies how can we even + + + align:start position:0% +have good Water Supplies how can we even +track which pumps are actually + + align:start position:0% +track which pumps are actually + + + align:start position:0% +track which pumps are actually +functioning using cell phone connections + + align:start position:0% +functioning using cell phone connections + + + align:start position:0% +functioning using cell phone connections +to those how do we overload that with + + align:start position:0% +to those how do we overload that with + + + align:start position:0% +to those how do we overload that with +social networks and actually manage to + + align:start position:0% +social networks and actually manage to + + + align:start position:0% +social networks and actually manage to +track the cholera outbreak through those + + align:start position:0% +track the cholera outbreak through those + + + align:start position:0% +track the cholera outbreak through those +as well so I think there's a lot of + + align:start position:0% +as well so I think there's a lot of + + + align:start position:0% +as well so I think there's a lot of +areas where there's overlap but I will + + align:start position:0% +areas where there's overlap but I will + + + align:start position:0% +areas where there's overlap but I will +not take over this ad just first of all + + align:start position:0% +not take over this ad just first of all + + + align:start position:0% +not take over this ad just first of all +just like to say + + align:start position:0% +just like to say + + + align:start position:0% +just like to say +um doing the students in the class have + + align:start position:0% +um doing the students in the class have + + + align:start position:0% +um doing the students in the class have +questions + + align:start position:0% + + + + align:start position:0% + +yes please if you don't mind introducing + + align:start position:0% +yes please if you don't mind introducing + + + align:start position:0% +yes please if you don't mind introducing +yourself just in the hopes that I will + + align:start position:0% +yourself just in the hopes that I will + + + align:start position:0% +yourself just in the hopes that I will +stay in touch with some of you my name + + align:start position:0% +stay in touch with some of you my name + + + align:start position:0% +stay in touch with some of you my name +is Sherry Ward and and they engage + + align:start position:0% +is Sherry Ward and and they engage + + + align:start position:0% +is Sherry Ward and and they engage +program over at the Harvard School of + + align:start position:0% +program over at the Harvard School of + + + align:start position:0% +program over at the Harvard School of +global Health in the global Health + + align:start position:0% +global Health in the global Health + + + align:start position:0% +global Health in the global Health +Department thank you for coming thank + + align:start position:0% +Department thank you for coming thank + + + align:start position:0% +Department thank you for coming thank +you and I also wanted to say thank you I + + align:start position:0% +you and I also wanted to say thank you I + + + align:start position:0% +you and I also wanted to say thank you I +heard you speak in mayor Blair and in + + align:start position:0% +heard you speak in mayor Blair and in + + + align:start position:0% +heard you speak in mayor Blair and in +January did I did I cry or not + + align:start position:0% +January did I did I cry or not + + + align:start position:0% +January did I did I cry or not +oh that was very emotional but it really + + align:start position:0% +oh that was very emotional but it really + + + align:start position:0% +oh that was very emotional but it really +affected the way I + + align:start position:0% + + + + align:start position:0% + +well thank you for coming all the way to + + align:start position:0% +well thank you for coming all the way to + + + align:start position:0% +well thank you for coming all the way to +Haiti to hear it + + align:start position:0% +Haiti to hear it + + + align:start position:0% +Haiti to hear it +thank you um another question is what + + align:start position:0% +thank you um another question is what + + + align:start position:0% +thank you um another question is what +has been your experience with any M + + align:start position:0% +has been your experience with any M + + + align:start position:0% +has been your experience with any M +Health technology and either yourself or + + align:start position:0% +Health technology and either yourself or + + + align:start position:0% +Health technology and either yourself or +with Partners in Health that was very + + align:start position:0% +with Partners in Health that was very + + + align:start position:0% +with Partners in Health that was very +successful that you felt made a big + + align:start position:0% +successful that you felt made a big + + + align:start position:0% +successful that you felt made a big +difference in patient outcomes and why + + align:start position:0% +difference in patient outcomes and why + + + align:start position:0% +difference in patient outcomes and why +do you feel that those specific programs + + align:start position:0% +do you feel that those specific programs + + + align:start position:0% +do you feel that those specific programs +well I'm going to tell you again for as + + align:start position:0% +well I'm going to tell you again for as + + + align:start position:0% +well I'm going to tell you again for as +the as The Outsider and then ask Hamish + + align:start position:0% +the as The Outsider and then ask Hamish + + + align:start position:0% +the as The Outsider and then ask Hamish +to to comment on that the outsider + + align:start position:0% +to to comment on that the outsider + + + align:start position:0% +to to comment on that the outsider +meaning The Insider clinically + + align:start position:0% +meaning The Insider clinically + + + align:start position:0% +meaning The Insider clinically +um I would if I had to choose one uh + + align:start position:0% +um I would if I had to choose one uh + + + align:start position:0% +um I would if I had to choose one uh +leaving aside the electronic medical + + align:start position:0% +leaving aside the electronic medical + + + align:start position:0% +leaving aside the electronic medical +record you said M mobile right it would + + align:start position:0% +record you said M mobile right it would + + + align:start position:0% +record you said M mobile right it would +be the cell phone uh the use of cell + + align:start position:0% +be the cell phone uh the use of cell + + + align:start position:0% +be the cell phone uh the use of cell +phones by community health workers in + + align:start position:0% +phones by community health workers in + + + align:start position:0% +phones by community health workers in +Peru to manage complex uh pharmacopoeia + + align:start position:0% +Peru to manage complex uh pharmacopoeia + + + align:start position:0% +Peru to manage complex uh pharmacopoeia +you know these these regimens that are + + align:start position:0% +you know these these regimens that are + + + align:start position:0% +you know these these regimens that are +sometimes I have 10 12 15 medications + + align:start position:0% +sometimes I have 10 12 15 medications + + + align:start position:0% +sometimes I have 10 12 15 medications +and I would say that that is probably a + + align:start position:0% +and I would say that that is probably a + + + align:start position:0% +and I would say that that is probably a +and my colleagues are doing that in + + align:start position:0% +and my colleagues are doing that in + + + align:start position:0% +and my colleagues are doing that in +Mexico in Rwanda now in Haiti but the + + align:start position:0% +Mexico in Rwanda now in Haiti but the + + + align:start position:0% +Mexico in Rwanda now in Haiti but the +Peruvian + + align:start position:0% +Peruvian + + + align:start position:0% +Peruvian +it looks to me that they're really the + + align:start position:0% +it looks to me that they're really the + + + align:start position:0% +it looks to me that they're really the +community health workers really can't + + align:start position:0% +community health workers really can't + + + align:start position:0% +community health workers really can't +work without it and in their handheld + + align:start position:0% +work without it and in their handheld + + + align:start position:0% +work without it and in their handheld +devices am I right or not + + align:start position:0% +devices am I right or not + + + align:start position:0% +devices am I right or not +I mean actually Mexico in particular + + align:start position:0% +I mean actually Mexico in particular + + + align:start position:0% +I mean actually Mexico in particular +Davenport Services work looking at um + + align:start position:0% +Davenport Services work looking at um + + + align:start position:0% +Davenport Services work looking at um +how you can simplify prescribing of such + + align:start position:0% +how you can simplify prescribing of such + + + align:start position:0% +how you can simplify prescribing of such +medications and providing that support + + align:start position:0% +medications and providing that support + + + align:start position:0% +medications and providing that support +is probably the most advanced one that + + align:start position:0% +is probably the most advanced one that + + + align:start position:0% +is probably the most advanced one that +we're being looking at I mean I think + + align:start position:0% +we're being looking at I mean I think + + + align:start position:0% +we're being looking at I mean I think +there there's a huge amount of energy in + + align:start position:0% +there there's a huge amount of energy in + + + align:start position:0% +there there's a huge amount of energy in +NF at this point and many people looking + + align:start position:0% +NF at this point and many people looking + + + align:start position:0% +NF at this point and many people looking +at different ways we can use it I would + + align:start position:0% +at different ways we can use it I would + + + align:start position:0% +at different ways we can use it I would +say that we we've had specific benefits + + align:start position:0% +say that we we've had specific benefits + + + align:start position:0% +say that we we've had specific benefits +the other thing to improve actually is + + align:start position:0% +the other thing to improve actually is + + + align:start position:0% +the other thing to improve actually is +the Palm Pilots before that's what I + + align:start position:0% +the Palm Pilots before that's what I + + + align:start position:0% +the Palm Pilots before that's what I +mean handheld devices and be able to + + align:start position:0% +mean handheld devices and be able to + + + align:start position:0% +mean handheld devices and be able to +collect that data and improve quality if + + align:start position:0% +collect that data and improve quality if + + + align:start position:0% +collect that data and improve quality if +it's also access the lab data I know + + align:start position:0% +it's also access the lab data I know + + + align:start position:0% +it's also access the lab data I know +that their app is also interested in + + align:start position:0% +that their app is also interested in + + + align:start position:0% +that their app is also interested in +this question how do we actually get the + + align:start position:0% +this question how do we actually get the + + + align:start position:0% +this question how do we actually get the +lab data from the from the market maybe + + align:start position:0% +lab data from the from the market maybe + + + align:start position:0% +lab data from the from the market maybe +the remote car from the patients back to + + align:start position:0% +the remote car from the patients back to + + + align:start position:0% +the remote car from the patients back to +the clinician's caring for those + + align:start position:0% +the clinician's caring for those + + + align:start position:0% +the clinician's caring for those +patients and that's thinking pushes I + + align:start position:0% +patients and that's thinking pushes I + + + align:start position:0% +patients and that's thinking pushes I +mean going forward there's the big + + align:start position:0% +mean going forward there's the big + + + align:start position:0% +mean going forward there's the big +question this is actually one that I'm + + align:start position:0% +question this is actually one that I'm + + + align:start position:0% +question this is actually one that I'm +very interested in + + align:start position:0% +very interested in + + + align:start position:0% +very interested in +um two grand national forecast we talked + + align:start position:0% +um two grand national forecast we talked + + + align:start position:0% +um two grand national forecast we talked +about in the class looking at text + + align:start position:0% +about in the class looking at text + + + align:start position:0% +about in the class looking at text +message reminders for patients to take + + align:start position:0% +message reminders for patients to take + + + align:start position:0% +message reminders for patients to take +their HIV medications and show them that + + align:start position:0% +their HIV medications and show them that + + + align:start position:0% +their HIV medications and show them that +there was a benefit of that but at the + + align:start position:0% +there was a benefit of that but at the + + + align:start position:0% +there was a benefit of that but at the +same time + + align:start position:0% +same time + + + align:start position:0% +same time +food to my knowledge and I think we're + + align:start position:0% +food to my knowledge and I think we're + + + align:start position:0% +food to my knowledge and I think we're +still trying to map this out this is not + + align:start position:0% +still trying to map this out this is not + + + align:start position:0% +still trying to map this out this is not +as effective as a community healthcare + + align:start position:0% +as effective as a community healthcare + + + align:start position:0% +as effective as a community healthcare +worker plus do that and so there's a big + + align:start position:0% +worker plus do that and so there's a big + + + align:start position:0% +worker plus do that and so there's a big +interesting question that we have not + + align:start position:0% +interesting question that we have not + + + align:start position:0% +interesting question that we have not +resolved is how well does the company + + align:start position:0% +resolved is how well does the company + + + align:start position:0% +resolved is how well does the company +internal model function in different + + align:start position:0% +internal model function in different + + + align:start position:0% +internal model function in different +environments relative to the phone and I + + align:start position:0% +environments relative to the phone and I + + + align:start position:0% +environments relative to the phone and I +I believe that the New Hampshire worker + + align:start position:0% +I believe that the New Hampshire worker + + + align:start position:0% +I believe that the New Hampshire worker +is actually much more effective + + align:start position:0% +is actually much more effective + + + align:start position:0% +is actually much more effective +approach however there's also the + + align:start position:0% +approach however there's also the + + + align:start position:0% +approach however there's also the +questions of how you organize that so + + align:start position:0% +questions of how you organize that so + + + align:start position:0% +questions of how you organize that so +there's a big interesting question in + + align:start position:0% +there's a big interesting question in + + + align:start position:0% +there's a big interesting question in +the public health aspect which I think + + align:start position:0% +the public health aspect which I think + + + align:start position:0% +the public health aspect which I think +is going to be one of the important + + align:start position:0% +is going to be one of the important + + + align:start position:0% +is going to be one of the important +things going forward in the next couple + + align:start position:0% +things going forward in the next couple + + + align:start position:0% +things going forward in the next couple +of years if I could just add to that + + align:start position:0% +of years if I could just add to that + + + align:start position:0% +of years if I could just add to that +back to the question of comparing some + + align:start position:0% +back to the question of comparing some + + + align:start position:0% +back to the question of comparing some +of the neat gadgetry that has been + + align:start position:0% +of the neat gadgetry that has been + + + align:start position:0% +of the neat gadgetry that has been +Advanced by MIT specifically one of them + + align:start position:0% +Advanced by MIT specifically one of them + + + align:start position:0% +Advanced by MIT specifically one of them +I remember was + + align:start position:0% +I remember was + + + align:start position:0% +I remember was +a a urine strip to test isoniazide + + align:start position:0% +a a urine strip to test isoniazide + + + align:start position:0% +a a urine strip to test isoniazide +levels in the blood to see if you were + + align:start position:0% +levels in the blood to see if you were + + + align:start position:0% +levels in the blood to see if you were +actually complying with your regimen for + + align:start position:0% +actually complying with your regimen for + + + align:start position:0% +actually complying with your regimen for +tuberculosis and I was saying okay then + + align:start position:0% +tuberculosis and I was saying okay then + + + align:start position:0% +tuberculosis and I was saying okay then +you feed the strip into a cool little + + align:start position:0% +you feed the strip into a cool little + + + align:start position:0% +you feed the strip into a cool little +handout machine and but you could have + + align:start position:0% +handout machine and but you could have + + + align:start position:0% +handout machine and but you could have +given someone a job to be the community + + align:start position:0% +given someone a job to be the community + + + align:start position:0% +given someone a job to be the community +health worker and visit the patron and + + align:start position:0% +health worker and visit the patron and + + + align:start position:0% +health worker and visit the patron and +accompaniment so this is another I I + + align:start position:0% +accompaniment so this is another I I + + + align:start position:0% +accompaniment so this is another I I +don't want to sound like a Luddite I + + align:start position:0% +don't want to sound like a Luddite I + + + align:start position:0% +don't want to sound like a Luddite I +believe that it's the technical term + + align:start position:0% +believe that it's the technical term + + + align:start position:0% +believe that it's the technical term +remember for Ned blood and if I don't + + align:start position:0% +remember for Ned blood and if I don't + + + align:start position:0% +remember for Ned blood and if I don't +even know if he was a real person but + + align:start position:0% +even know if he was a real person but + + + align:start position:0% +even know if he was a real person but +trying to slow down in your peeps trying + + align:start position:0% +trying to slow down in your peeps trying + + + align:start position:0% +trying to slow down in your peeps trying +to slow down the Industrial Revolution + + align:start position:0% +to slow down the Industrial Revolution + + + align:start position:0% +to slow down the Industrial Revolution +on the contrary I'm not I'm just saying + + align:start position:0% +on the contrary I'm not I'm just saying + + + align:start position:0% +on the contrary I'm not I'm just saying +we need to learn how to measure + + align:start position:0% +we need to learn how to measure + + + align:start position:0% +we need to learn how to measure +especially you know at the school public + + align:start position:0% +especially you know at the school public + + + align:start position:0% +especially you know at the school public +out there in an economics Department + + align:start position:0% +out there in an economics Department + + + align:start position:0% +out there in an economics Department +this the positive impact of actually + + align:start position:0% +this the positive impact of actually + + + align:start position:0% +this the positive impact of actually +reducing unemployment + + align:start position:0% +reducing unemployment + + + align:start position:0% +reducing unemployment +and then community health workers are + + align:start position:0% +and then community health workers are + + + align:start position:0% +and then community health workers are +Far and Away the largest + + align:start position:0% +Far and Away the largest + + + align:start position:0% +Far and Away the largest +fraction of workers at partisan Health + + align:start position:0% +fraction of workers at partisan Health + + + align:start position:0% +fraction of workers at partisan Health +which is counts probably fifteen + + align:start position:0% +which is counts probably fifteen + + + align:start position:0% +which is counts probably fifteen +thousand + + align:start position:0% +thousand + + + align:start position:0% +thousand +employees and most of them have never + + align:start position:0% +employees and most of them have never + + + align:start position:0% +employees and most of them have never +had a job before so there's this + + align:start position:0% +had a job before so there's this + + + align:start position:0% +had a job before so there's this +virtuous social cycle that gets started + + align:start position:0% +virtuous social cycle that gets started + + + align:start position:0% +virtuous social cycle that gets started +just by using human labor when you can + + align:start position:0% +just by using human labor when you can + + + align:start position:0% +just by using human labor when you can +and you want to never fail to integrate + + align:start position:0% +and you want to never fail to integrate + + + align:start position:0% +and you want to never fail to integrate +new technology at the same time that you + + align:start position:0% +new technology at the same time that you + + + align:start position:0% +new technology at the same time that you +would learn how to Value positively + + align:start position:0% +would learn how to Value positively + + + align:start position:0% +would learn how to Value positively +giving a job to Community Health program + + align:start position:0% +giving a job to Community Health program + + + align:start position:0% +giving a job to Community Health program +which by the way still as I said + + align:start position:0% +which by the way still as I said + + + align:start position:0% +which by the way still as I said +delivers a better service but also has + + align:start position:0% +delivers a better service but also has + + + align:start position:0% +delivers a better service but also has +these other things we need to learn how + + align:start position:0% +these other things we need to learn how + + + align:start position:0% +these other things we need to learn how +to study I mean something that we're + + align:start position:0% +to study I mean something that we're + + + align:start position:0% +to study I mean something that we're +doing a lot at the moment yeah just + + align:start position:0% +doing a lot at the moment yeah just + + + align:start position:0% +doing a lot at the moment yeah just +looking at how the really effective + + align:start position:0% +looking at how the really effective + + + align:start position:0% +looking at how the really effective +community health care worker programs + + align:start position:0% +community health care worker programs + + + align:start position:0% +community health care worker programs +and the training and the way that those + + align:start position:0% +and the training and the way that those + + + align:start position:0% +and the training and the way that those +have been set up and managed can be + + align:start position:0% +have been set up and managed can be + + + align:start position:0% +have been set up and managed can be +linked to these mobile appliances and + + align:start position:0% +linked to these mobile appliances and + + + align:start position:0% +linked to these mobile appliances and +that's in Reliance in particular we've + + align:start position:0% +that's in Reliance in particular we've + + + align:start position:0% +that's in Reliance in particular we've +got a 40 000 community healthcare + + align:start position:0% +got a 40 000 community healthcare + + + align:start position:0% +got a 40 000 community healthcare +workers hard by the government and being + + align:start position:0% +workers hard by the government and being + + + align:start position:0% +workers hard by the government and being +trained they are working really hard on + + align:start position:0% +trained they are working really hard on + + + align:start position:0% +trained they are working really hard on +how we can actually look at using + + align:start position:0% +how we can actually look at using + + + align:start position:0% +how we can actually look at using +initiative text messaging rapid SMS but + + align:start position:0% +initiative text messaging rapid SMS but + + + align:start position:0% +initiative text messaging rapid SMS but +you know other than that can we actually + + align:start position:0% +you know other than that can we actually + + + align:start position:0% +you know other than that can we actually +build on the phones with both of those + + align:start position:0% +build on the phones with both of those + + + align:start position:0% +build on the phones with both of those +things the the community the employment + + align:start position:0% +things the the community the employment + + + align:start position:0% +things the the community the employment +that people could really get into the + + align:start position:0% +that people could really get into the + + + align:start position:0% +that people could really get into the +patient's homes but also linking that so + + align:start position:0% +patient's homes but also linking that so + + + align:start position:0% +patient's homes but also linking that so +that you can for example Ensure if + + align:start position:0% +that you can for example Ensure if + + + align:start position:0% +that you can for example Ensure if +somebody has TV and it wasn't known when + + align:start position:0% +somebody has TV and it wasn't known when + + + align:start position:0% +somebody has TV and it wasn't known when +they were in the clinic that you can get + + align:start position:0% +they were in the clinic that you can get + + + align:start position:0% +they were in the clinic that you can get +that message to your healthcare worker + + align:start position:0% +that message to your healthcare worker + + + align:start position:0% +that message to your healthcare worker +and bring them into you know for further + + align:start position:0% +and bring them into you know for further + + + align:start position:0% +and bring them into you know for further +treatment + + align:start position:0% + + + + align:start position:0% + +another question yes please + + align:start position:0% +another question yes please + + + align:start position:0% +another question yes please +[Music] + + align:start position:0% + + + + align:start position:0% + +say I've been reading a lot of her books + + align:start position:0% +say I've been reading a lot of her books + + + align:start position:0% +say I've been reading a lot of her books +oh don't say needless to say stay away + + align:start position:0% + + + + align:start position:0% + +so I've been following your words + + align:start position:0% + + + + align:start position:0% + +here and I'm grateful to be here + + align:start position:0% +here and I'm grateful to be here + + + align:start position:0% +here and I'm grateful to be here +my first husband + + align:start position:0% +my first husband + + + align:start position:0% +my first husband +throughout this class in my anthropology + + align:start position:0% +throughout this class in my anthropology + + + align:start position:0% +throughout this class in my anthropology +studies how to Major and maintain + + align:start position:0% +studies how to Major and maintain + + + align:start position:0% +studies how to Major and maintain +quality of care in those settings when + + align:start position:0% +quality of care in those settings when + + + align:start position:0% +quality of care in those settings when +the priority is in giving access and in + + align:start position:0% +the priority is in giving access and in + + + align:start position:0% +the priority is in giving access and in +maintaining sustainability so the Health + + align:start position:0% +maintaining sustainability so the Health + + + align:start position:0% +maintaining sustainability so the Health +Care system + + align:start position:0% +Care system + + + align:start position:0% +Care system +animating to maintain um + + align:start position:0% + + + + align:start position:0% + +earlier but I was wondering yeah well um + + align:start position:0% +earlier but I was wondering yeah well um + + + align:start position:0% +earlier but I was wondering yeah well um +first of all this is a it's not that I + + align:start position:0% +first of all this is a it's not that I + + + align:start position:0% +first of all this is a it's not that I +didn't want to talk about it it's just + + align:start position:0% +didn't want to talk about it it's just + + + align:start position:0% +didn't want to talk about it it's just +such a humbling topic + + align:start position:0% +such a humbling topic + + + align:start position:0% +such a humbling topic +um the quality issue so again we were + + align:start position:0% +um the quality issue so again we were + + + align:start position:0% +um the quality issue so again we were +moving towards scale but I would say the + + align:start position:0% +moving towards scale but I would say the + + + align:start position:0% +moving towards scale but I would say the +main reason that our organization + + align:start position:0% +main reason that our organization + + + align:start position:0% +main reason that our organization +is in 25 countries but rather only in 12 + + align:start position:0% +is in 25 countries but rather only in 12 + + + align:start position:0% +is in 25 countries but rather only in 12 +and isn't trying to claim Nationwide + + align:start position:0% +and isn't trying to claim Nationwide + + + align:start position:0% +and isn't trying to claim Nationwide +coverage + + align:start position:0% +coverage + + + align:start position:0% +coverage +is because of uh I hope a humility about + + align:start position:0% +is because of uh I hope a humility about + + + align:start position:0% +is because of uh I hope a humility about +quality we don't believe that it's that + + align:start position:0% +quality we don't believe that it's that + + + align:start position:0% +quality we don't believe that it's that +easy to just go in and fit it with the + + align:start position:0% +easy to just go in and fit it with the + + + align:start position:0% +easy to just go in and fit it with the +policy and and suddenly the quality of + + align:start position:0% +policy and and suddenly the quality of + + + align:start position:0% +policy and and suddenly the quality of +care changes on a national level + + align:start position:0% +care changes on a national level + + + align:start position:0% +care changes on a national level +sometimes you know but it's usually a + + align:start position:0% +sometimes you know but it's usually a + + + align:start position:0% +sometimes you know but it's usually a +mix of resources human and and other + + align:start position:0% +mix of resources human and and other + + + align:start position:0% +mix of resources human and and other +kinds of capital and then the + + align:start position:0% +kinds of capital and then the + + + align:start position:0% +kinds of capital and then the +implementation so we're very focused on + + align:start position:0% +implementation so we're very focused on + + + align:start position:0% +implementation so we're very focused on +implementation and even with that Focus + + align:start position:0% +implementation and even with that Focus + + + align:start position:0% +implementation and even with that Focus +I would say that we you know we've had a + + align:start position:0% +I would say that we you know we've had a + + + align:start position:0% +I would say that we you know we've had a +you know a big quality problem with + + align:start position:0% +you know a big quality problem with + + + align:start position:0% +you know a big quality problem with +scale just like everybody else so that's + + align:start position:0% +scale just like everybody else so that's + + + align:start position:0% +scale just like everybody else so that's +what we're struggling you ask me what + + align:start position:0% +what we're struggling you ask me what + + + align:start position:0% +what we're struggling you ask me what +measures okay + + align:start position:0% +measures okay + + + align:start position:0% +measures okay +um there there most of them are proxy + + align:start position:0% +um there there most of them are proxy + + + align:start position:0% +um there there most of them are proxy +measures like I mentioned one right I + + align:start position:0% +measures like I mentioned one right I + + + align:start position:0% +measures like I mentioned one right I +said I didn't really say it but I'm + + align:start position:0% +said I didn't really say it but I'm + + + align:start position:0% +said I didn't really say it but I'm +going to say it now + + align:start position:0% +going to say it now + + + align:start position:0% +going to say it now +just look when you're looking at + + align:start position:0% +just look when you're looking at + + + align:start position:0% +just look when you're looking at +outcomes + + align:start position:0% +outcomes + + + align:start position:0% +outcomes +of HIV and TB care you obviously have + + align:start position:0% +of HIV and TB care you obviously have + + + align:start position:0% +of HIV and TB care you obviously have +you can use viral load right for HIV for + + align:start position:0% +you can use viral load right for HIV for + + + align:start position:0% +you can use viral load right for HIV for +TB you can use smear my Cosby microscopy + + align:start position:0% +TB you can use smear my Cosby microscopy + + + align:start position:0% +TB you can use smear my Cosby microscopy +or some of the new diagnosis but you can + + align:start position:0% +or some of the new diagnosis but you can + + + align:start position:0% +or some of the new diagnosis but you can +all just also just weigh the patients + + align:start position:0% +all just also just weigh the patients + + + align:start position:0% +all just also just weigh the patients +so again a proxy measure for quality of + + align:start position:0% +so again a proxy measure for quality of + + + align:start position:0% +so again a proxy measure for quality of +services is if they gain 20 pounds + + align:start position:0% +services is if they gain 20 pounds + + + align:start position:0% +services is if they gain 20 pounds +you know like Joseph did and and John + + align:start position:0% +you know like Joseph did and and John + + + align:start position:0% +you know like Joseph did and and John +that was the name of the other guy + + align:start position:0% +that was the name of the other guy + + + align:start position:0% +that was the name of the other guy +then that's a pretty good proxy measure + + align:start position:0% +then that's a pretty good proxy measure + + + align:start position:0% +then that's a pretty good proxy measure +it's inexpensive and it can be sent in + + align:start position:0% +it's inexpensive and it can be sent in + + + align:start position:0% +it's inexpensive and it can be sent in +by a mobile technology now let me just I + + align:start position:0% +by a mobile technology now let me just I + + + align:start position:0% +by a mobile technology now let me just I +can go through this like for Diabetes + + align:start position:0% +can go through this like for Diabetes + + + align:start position:0% +can go through this like for Diabetes +Care well hemoglobin A1c is is one + + align:start position:0% +Care well hemoglobin A1c is is one + + + align:start position:0% +Care well hemoglobin A1c is is one +measure right so you can imagine again a + + align:start position:0% +measure right so you can imagine again a + + + align:start position:0% +measure right so you can imagine again a +hand this time I would actually say it'd + + align:start position:0% +hand this time I would actually say it'd + + + align:start position:0% +hand this time I would actually say it'd +be better to have a handheld device that + + align:start position:0% +be better to have a handheld device that + + + align:start position:0% +be better to have a handheld device that +could actually be introduced a fingers + + align:start position:0% +could actually be introduced a fingers + + + align:start position:0% +could actually be introduced a fingers +thick is painful some of you know but + + align:start position:0% +thick is painful some of you know but + + + align:start position:0% +thick is painful some of you know but +get a sample that is able to tell you + + align:start position:0% +get a sample that is able to tell you + + + align:start position:0% +get a sample that is able to tell you +well what's the blood sugar and what's + + align:start position:0% +well what's the blood sugar and what's + + + align:start position:0% +well what's the blood sugar and what's +the hemoglobin m1c is there proxies of + + align:start position:0% +the hemoglobin m1c is there proxies of + + + align:start position:0% +the hemoglobin m1c is there proxies of +quality you could use as people at this + + align:start position:0% +quality you could use as people at this + + + align:start position:0% +quality you could use as people at this +institution have are sort of the pros + + align:start position:0% +institution have are sort of the pros + + + align:start position:0% +institution have are sort of the pros +now in random you know randomized Trials + + align:start position:0% +now in random you know randomized Trials + + + align:start position:0% +now in random you know randomized Trials +of positive social outcomes they're + + align:start position:0% +of positive social outcomes they're + + + align:start position:0% +of positive social outcomes they're +using you are using those who do that + + align:start position:0% +using you are using those who do that + + + align:start position:0% +using you are using those who do that +we're proxy measures so I found there's + + align:start position:0% +we're proxy measures so I found there's + + + align:start position:0% +we're proxy measures so I found there's +a long list of them and even in a + + align:start position:0% +a long list of them and even in a + + + align:start position:0% +a long list of them and even in a +setting where you wouldn't easily have + + align:start position:0% +setting where you wouldn't easily have + + + align:start position:0% +setting where you wouldn't easily have +access to a lab or you wouldn't have + + align:start position:0% +access to a lab or you wouldn't have + + + align:start position:0% +access to a lab or you wouldn't have +access to uh you know a researcher who + + align:start position:0% +access to uh you know a researcher who + + + align:start position:0% +access to uh you know a researcher who +is registering things is using + + align:start position:0% +is registering things is using + + + align:start position:0% +is registering things is using +questionnaire you still if you have this + + align:start position:0% +questionnaire you still if you have this + + + align:start position:0% +questionnaire you still if you have this +network this platform you still have + + align:start position:0% +network this platform you still have + + + align:start position:0% +network this platform you still have +your community health workers and they + + align:start position:0% +your community health workers and they + + + align:start position:0% +your community health workers and they +can manage quite a bit of + + align:start position:0% +can manage quite a bit of + + + align:start position:0% +can manage quite a bit of +complexity in terms of reporting if + + align:start position:0% +complexity in terms of reporting if + + + align:start position:0% +complexity in terms of reporting if +they're supported fully so I think for + + align:start position:0% +they're supported fully so I think for + + + align:start position:0% +they're supported fully so I think for +each of these problems you can find + + align:start position:0% +each of these problems you can find + + + align:start position:0% +each of these problems you can find +proxy measures for Quality now I would + + align:start position:0% +proxy measures for Quality now I would + + + align:start position:0% +proxy measures for Quality now I would +add in and I'm just learning about this + + align:start position:0% +add in and I'm just learning about this + + + align:start position:0% +add in and I'm just learning about this +uh Julia Frank your boss is he has a + + align:start position:0% +uh Julia Frank your boss is he has a + + + align:start position:0% +uh Julia Frank your boss is he has a +mentor I think at University of Michigan + + align:start position:0% +mentor I think at University of Michigan + + + align:start position:0% +mentor I think at University of Michigan +I had a mentor who's sort of the father + + align:start position:0% +I had a mentor who's sort of the father + + + align:start position:0% +I had a mentor who's sort of the father +of quality improvement from the 70s and + + align:start position:0% +of quality improvement from the 70s and + + + align:start position:0% +of quality improvement from the 70s and +80s wrote a paper evidently in Milbank + + align:start position:0% +80s wrote a paper evidently in Milbank + + + align:start position:0% +80s wrote a paper evidently in Milbank +quarterly in 1960 something Julio Frank + + align:start position:0% +quarterly in 1960 something Julio Frank + + + align:start position:0% +quarterly in 1960 something Julio Frank +just told me this and he not earlier but + + align:start position:0% +just told me this and he not earlier but + + + align:start position:0% +just told me this and he not earlier but +his mentor one of them said that there + + align:start position:0% +his mentor one of them said that there + + + align:start position:0% +his mentor one of them said that there +are many kinds of quality there's + + align:start position:0% +are many kinds of quality there's + + + align:start position:0% +are many kinds of quality there's +technical technically confident quality + + align:start position:0% +technical technically confident quality + + + align:start position:0% +technical technically confident quality +the least we could do but there's also + + align:start position:0% +the least we could do but there's also + + + align:start position:0% +the least we could do but there's also +respect for the rights of the person the + + align:start position:0% +respect for the rights of the person the + + + align:start position:0% +respect for the rights of the person the +so-called client patient and uh you know + + align:start position:0% +so-called client patient and uh you know + + + align:start position:0% +so-called client patient and uh you know +what about the Dignity of the + + align:start position:0% +what about the Dignity of the + + + align:start position:0% +what about the Dignity of the +surroundings in which the care is + + align:start position:0% +surroundings in which the care is + + + align:start position:0% +surroundings in which the care is +delivered like we've focused a lot on + + align:start position:0% +delivered like we've focused a lot on + + + align:start position:0% +delivered like we've focused a lot on +them and Julio has been helping us yeah + + align:start position:0% +them and Julio has been helping us yeah + + + align:start position:0% +them and Julio has been helping us yeah +but + + align:start position:0% +but + + + align:start position:0% +but +um + + align:start position:0% + + + + align:start position:0% + +that is tough wow + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +for example I think you're looking at + + align:start position:0% +for example I think you're looking at + + + align:start position:0% +for example I think you're looking at +the entire care coverage a lot of the + + align:start position:0% +the entire care coverage a lot of the + + + align:start position:0% +the entire care coverage a lot of the +programs and increasing use of that I + + align:start position:0% +programs and increasing use of that I + + + align:start position:0% +programs and increasing use of that I +would say it has been covered that + + align:start position:0% +would say it has been covered that + + + align:start position:0% +would say it has been covered that +incentivizing women through vouchers and + + align:start position:0% +incentivizing women through vouchers and + + + align:start position:0% +incentivizing women through vouchers and +cash transfers + + align:start position:0% +cash transfers + + + align:start position:0% +cash transfers +from a technology example how would you + + align:start position:0% +from a technology example how would you + + + align:start position:0% +from a technology example how would you +use technology to to get people and say + + align:start position:0% +use technology to to get people and say + + + align:start position:0% +use technology to to get people and say +to find you something like ANC yeah well + + align:start position:0% +to find you something like ANC yeah well + + + align:start position:0% +to find you something like ANC yeah well +first of all I'm glad you asked me first + + align:start position:0% +first of all I'm glad you asked me first + + + align:start position:0% +first of all I'm glad you asked me first +of all but first of all I think there's + + align:start position:0% +of all but first of all I think there's + + + align:start position:0% +of all but first of all I think there's +a right track and a wrong track and the + + align:start position:0% +a right track and a wrong track and the + + + align:start position:0% +a right track and a wrong track and the +right track is the cash transfer part + + align:start position:0% +right track is the cash transfer part + + + align:start position:0% +right track is the cash transfer part +the wrong track is trying to you know + + align:start position:0% +the wrong track is trying to you know + + + align:start position:0% +the wrong track is trying to you know +then again this is I have a colleague + + align:start position:0% +then again this is I have a colleague + + + align:start position:0% +then again this is I have a colleague +here and I'll see how she thinks I do + + align:start position:0% +here and I'll see how she thinks I do + + + align:start position:0% +here and I'll see how she thinks I do +there's so little knowledge in public + + align:start position:0% +there's so little knowledge in public + + + align:start position:0% +there's so little knowledge in public +health of how + + align:start position:0% +health of how + + + align:start position:0% +health of how +structural problems poverty gender + + align:start position:0% +structural problems poverty gender + + + align:start position:0% +structural problems poverty gender +inequality travel Transportation + + align:start position:0% +inequality travel Transportation + + + align:start position:0% +inequality travel Transportation +whatever there's very very limited + + align:start position:0% +whatever there's very very limited + + + align:start position:0% +whatever there's very very limited +understanding of how those things + + align:start position:0% +understanding of how those things + + + align:start position:0% +understanding of how those things +determine agency the ability to choose + + align:start position:0% +determine agency the ability to choose + + + align:start position:0% +determine agency the ability to choose +so I would say the wrong way is to try + + align:start position:0% +so I would say the wrong way is to try + + + align:start position:0% +so I would say the wrong way is to try +and get people to Value things when we + + align:start position:0% +and get people to Value things when we + + + align:start position:0% +and get people to Value things when we +don't have evidence that they don't + + align:start position:0% +don't have evidence that they don't + + + align:start position:0% +don't have evidence that they don't +value them but we have evidence of is + + align:start position:0% +value them but we have evidence of is + + + align:start position:0% +value them but we have evidence of is +their inability to access them + + align:start position:0% +their inability to access them + + + align:start position:0% +their inability to access them +so this is It's a somewhat subtle point + + align:start position:0% +so this is It's a somewhat subtle point + + + align:start position:0% +so this is It's a somewhat subtle point +but I think cognitive approaches + + align:start position:0% +but I think cognitive approaches + + + align:start position:0% +but I think cognitive approaches +um to for example the promotion of of + + align:start position:0% +um to for example the promotion of of + + + align:start position:0% +um to for example the promotion of of +ANC + + align:start position:0% +ANC + + + align:start position:0% +ANC +um that is exhorting poor women to do + + align:start position:0% +um that is exhorting poor women to do + + + align:start position:0% +um that is exhorting poor women to do +what you want I think they're fraudulent + + align:start position:0% +what you want I think they're fraudulent + + + align:start position:0% +what you want I think they're fraudulent +and I also think they're heavily funded + + align:start position:0% +and I also think they're heavily funded + + + align:start position:0% +and I also think they're heavily funded +for a reason + + align:start position:0% +for a reason + + + align:start position:0% +for a reason +because what they do and yeah I want to + + align:start position:0% +because what they do and yeah I want to + + + align:start position:0% +because what they do and yeah I want to +see how you think I'm doing what they do + + align:start position:0% +see how you think I'm doing what they do + + + align:start position:0% +see how you think I'm doing what they do +what these approaches do is to move the + + align:start position:0% +what these approaches do is to move the + + + align:start position:0% +what these approaches do is to move the +locus of the problem into the head of + + align:start position:0% +locus of the problem into the head of + + + align:start position:0% +locus of the problem into the head of +the mother and out of her conditions + + align:start position:0% +the mother and out of her conditions + + + align:start position:0% +the mother and out of her conditions +right they're saying we have to make you + + align:start position:0% +right they're saying we have to make you + + + align:start position:0% +right they're saying we have to make you +value this because you don't value it + + align:start position:0% +value this because you don't value it + + + align:start position:0% +value this because you don't value it +what's the subject is you don't know + + align:start position:0% +what's the subject is you don't know + + + align:start position:0% +what's the subject is you don't know +you're not able to value and a NATO care + + align:start position:0% +you're not able to value and a NATO care + + + align:start position:0% +you're not able to value and a NATO care +but actually we don't have data for that + + align:start position:0% +but actually we don't have data for that + + + align:start position:0% +but actually we don't have data for that +but we have data forces that show that + + align:start position:0% +but we have data forces that show that + + + align:start position:0% +but we have data forces that show that +they don't there are barriers user fees + + align:start position:0% +they don't there are barriers user fees + + + align:start position:0% +they don't there are barriers user fees +transport you know who's going to + + align:start position:0% +transport you know who's going to + + + align:start position:0% +transport you know who's going to +babysit the other kids so when we and a + + align:start position:0% +babysit the other kids so when we and a + + + align:start position:0% +babysit the other kids so when we and a +lot of anthropologists would call those + + align:start position:0% +lot of anthropologists would call those + + + align:start position:0% +lot of anthropologists would call those +structural constraints as opposed to + + align:start position:0% +structural constraints as opposed to + + + align:start position:0% +structural constraints as opposed to +cultural or cognitive now here's the + + align:start position:0% +cultural or cognitive now here's the + + + align:start position:0% +cultural or cognitive now here's the +scam in my view and I guess that might + + align:start position:0% +scam in my view and I guess that might + + + align:start position:0% +scam in my view and I guess that might +as well know I'm transubmitting this + + align:start position:0% +as well know I'm transubmitting this + + + align:start position:0% +as well know I'm transubmitting this +around the world is that the idea that + + align:start position:0% +around the world is that the idea that + + + align:start position:0% +around the world is that the idea that +these are really the problems of poor + + align:start position:0% +these are really the problems of poor + + + align:start position:0% +these are really the problems of poor +people is really good for us people like + + align:start position:0% +people is really good for us people like + + + align:start position:0% +people is really good for us people like +you and me who go to places like + + align:start position:0% +you and me who go to places like + + + align:start position:0% +you and me who go to places like +Brandeis and Harvard because then we get + + align:start position:0% +Brandeis and Harvard because then we get + + + align:start position:0% +Brandeis and Harvard because then we get +a job afterwards if we can yell at poor + + align:start position:0% +a job afterwards if we can yell at poor + + + align:start position:0% +a job afterwards if we can yell at poor +ladies and tell them what to do right + + align:start position:0% +ladies and tell them what to do right + + + align:start position:0% +ladies and tell them what to do right +and we'll get funded for that for years + + align:start position:0% +and we'll get funded for that for years + + + align:start position:0% +and we'll get funded for that for years +and years and we'll even be able to + + align:start position:0% +and years and we'll even be able to + + + align:start position:0% +and years and we'll even be able to +repeat the cycle and do research on that + + align:start position:0% +repeat the cycle and do research on that + + + align:start position:0% +repeat the cycle and do research on that +as if we didn't already know that + + align:start position:0% +as if we didn't already know that + + + align:start position:0% +as if we didn't already know that +animatal care was good + + align:start position:0% +animatal care was good + + + align:start position:0% +animatal care was good +right so I think + + align:start position:0% +right so I think + + + align:start position:0% +right so I think +um you know how we use technology back + + align:start position:0% +um you know how we use technology back + + + align:start position:0% +um you know how we use technology back +to the point of your question in in + + align:start position:0% +to the point of your question in in + + + align:start position:0% +to the point of your question in in +something like making people value + + align:start position:0% +something like making people value + + + align:start position:0% +something like making people value +these good things that we believe in + + align:start position:0% +these good things that we believe in + + + align:start position:0% +these good things that we believe in +include cash transfers and even having + + align:start position:0% +include cash transfers and even having + + + align:start position:0% +include cash transfers and even having +for fan unconditional cash transfers + + align:start position:0% +for fan unconditional cash transfers + + + align:start position:0% +for fan unconditional cash transfers +because after all poor people have been + + align:start position:0% +because after all poor people have been + + + align:start position:0% +because after all poor people have been +making unconditional cash transfers to + + align:start position:0% +making unconditional cash transfers to + + + align:start position:0% +making unconditional cash transfers to +us for many centuries + + align:start position:0% +us for many centuries + + + align:start position:0% +us for many centuries +right you with me + + align:start position:0% +right you with me + + + align:start position:0% +right you with me +um so I think using those Technologies + + align:start position:0% +um so I think using those Technologies + + + align:start position:0% +um so I think using those Technologies +to transfer resources rather than just + + align:start position:0% +to transfer resources rather than just + + + align:start position:0% +to transfer resources rather than just +reminders and I I'll be looking forward + + align:start position:0% +reminders and I I'll be looking forward + + + align:start position:0% +reminders and I I'll be looking forward +to seeing the results of those studies + + align:start position:0% +to seeing the results of those studies + + + align:start position:0% +to seeing the results of those studies +but um you know reminders are one thing + + align:start position:0% +but um you know reminders are one thing + + + align:start position:0% +but um you know reminders are one thing +exploitations I'm calling them but just + + align:start position:0% +exploitations I'm calling them but just + + + align:start position:0% +exploitations I'm calling them but just +link these Technologies a little bit to + + align:start position:0% +link these Technologies a little bit to + + + align:start position:0% +link these Technologies a little bit to +removing barriers like for example if + + align:start position:0% +removing barriers like for example if + + + align:start position:0% +removing barriers like for example if +you if you look at structural barriers + + align:start position:0% +you if you look at structural barriers + + + align:start position:0% +you if you look at structural barriers +to care again I mentioned transport have + + align:start position:0% +to care again I mentioned transport have + + + align:start position:0% +to care again I mentioned transport have +the voucher go all the way out to the + + align:start position:0% +the voucher go all the way out to the + + + align:start position:0% +the voucher go all the way out to the +woman you know move the analog care to + + align:start position:0% +woman you know move the analog care to + + + align:start position:0% +woman you know move the analog care to +her or bring her to the Animal Care and + + align:start position:0% +her or bring her to the Animal Care and + + + align:start position:0% +her or bring her to the Animal Care and +again think about all these structural + + align:start position:0% +again think about all these structural + + + align:start position:0% +again think about all these structural +problems who's going to take care of the + + align:start position:0% +problems who's going to take care of the + + + align:start position:0% +problems who's going to take care of the +other kids how is she going to get there + + align:start position:0% +other kids how is she going to get there + + + align:start position:0% +other kids how is she going to get there +is there going to be a long line is + + align:start position:0% +is there going to be a long line is + + + align:start position:0% +is there going to be a long line is +there a hidden fee is there an open user + + align:start position:0% +there a hidden fee is there an open user + + + align:start position:0% +there a hidden fee is there an open user +view right because you find out people + + align:start position:0% +view right because you find out people + + + align:start position:0% +view right because you find out people +say we don't have any user fees and then + + align:start position:0% +say we don't have any user fees and then + + + align:start position:0% +say we don't have any user fees and then +you go and do research and there are + + align:start position:0% +you go and do research and there are + + + align:start position:0% +you go and do research and there are +user fees they may be hidden they may + + align:start position:0% +user fees they may be hidden they may + + + align:start position:0% +user fees they may be hidden they may +not so that's just my own personal take + + align:start position:0% +not so that's just my own personal take + + + align:start position:0% +not so that's just my own personal take +on that now I I don't go out to a + + align:start position:0% +on that now I I don't go out to a + + + align:start position:0% +on that now I I don't go out to a +conference on you know how to make women + + align:start position:0% +conference on you know how to make women + + + align:start position:0% +conference on you know how to make women +value into Nano care and say this stuff + + align:start position:0% +value into Nano care and say this stuff + + + align:start position:0% +value into Nano care and say this stuff +actually I don't go to those conferences + + align:start position:0% +actually I don't go to those conferences + + + align:start position:0% +actually I don't go to those conferences +anymore because I think they're a bit of + + align:start position:0% +anymore because I think they're a bit of + + + align:start position:0% +anymore because I think they're a bit of +a as I said a fraud + + align:start position:0% +a as I said a fraud + + + align:start position:0% +a as I said a fraud +so actually there's a question from + + align:start position:0% +so actually there's a question from + + + align:start position:0% +so actually there's a question from +Lauren who's when I got students who + + align:start position:0% +Lauren who's when I got students who + + + align:start position:0% +Lauren who's when I got students who +unfortunately can't be here today which + + align:start position:0% +unfortunately can't be here today which + + + align:start position:0% +unfortunately can't be here today which +I think is is very relevant um and it + + align:start position:0% +I think is is very relevant um and it + + + align:start position:0% +I think is is very relevant um and it +relates also to something that last + + align:start position:0% +relates also to something that last + + + align:start position:0% +relates also to something that last +weekend when I was in Haiti we were + + align:start position:0% +weekend when I was in Haiti we were + + + align:start position:0% +weekend when I was in Haiti we were +looking at our system which does very + + align:start position:0% +looking at our system which does very + + + align:start position:0% +looking at our system which does very +close to what Paul was describing the + + align:start position:0% +close to what Paul was describing the + + + align:start position:0% +close to what Paul was describing the +American Airlines where each patient is + + align:start position:0% +American Airlines where each patient is + + + align:start position:0% +American Airlines where each patient is +registered it only took you 10 years + + align:start position:0% +registered it only took you 10 years + + + align:start position:0% +registered it only took you 10 years +and you know for some good reasons + + align:start position:0% +and you know for some good reasons + + + align:start position:0% +and you know for some good reasons +um and to print out an ID card actually + + align:start position:0% +um and to print out an ID card actually + + + align:start position:0% +um and to print out an ID card actually +plastic idea on it and so each patient + + align:start position:0% +plastic idea on it and so each patient + + + align:start position:0% +plastic idea on it and so each patient +visits back and we can see we can come + + align:start position:0% +visits back and we can see we can come + + + align:start position:0% +visits back and we can see we can come +back and we can see the same person can + + align:start position:0% +back and we can see the same person can + + + align:start position:0% +back and we can see the same person can +only get to the lab data and so on so + + align:start position:0% +only get to the lab data and so on so + + + align:start position:0% +only get to the lab data and so on so +it's a very important foundational + + align:start position:0% +it's a very important foundational + + + align:start position:0% +it's a very important foundational +component which we hope to really be + + align:start position:0% +component which we hope to really be + + + align:start position:0% +component which we hope to really be +able to scale up in the new ballet + + align:start position:0% +able to scale up in the new ballet + + + align:start position:0% +able to scale up in the new ballet +hospital as a critical First Step + + align:start position:0% +hospital as a critical First Step + + + align:start position:0% +hospital as a critical First Step +um but it also introduces and kind of + + align:start position:0% +um but it also introduces and kind of + + + align:start position:0% +um but it also introduces and kind of +furthers one of the questions that we + + align:start position:0% +furthers one of the questions that we + + + align:start position:0% +furthers one of the questions that we +often get which is what are the + + align:start position:0% +often get which is what are the + + + align:start position:0% +often get which is what are the +quickoffs between collecting personal + + align:start position:0% +quickoffs between collecting personal + + + align:start position:0% +quickoffs between collecting personal +data in information systems and the + + align:start position:0% +data in information systems and the + + + align:start position:0% +data in information systems and the +potential risks or perceived risks that + + align:start position:0% +potential risks or perceived risks that + + + align:start position:0% +potential risks or perceived risks that +they pose to the patients and then the + + align:start position:0% +they pose to the patients and then the + + + align:start position:0% +they pose to the patients and then the +question of how to improve access to + + align:start position:0% +question of how to improve access to + + + align:start position:0% +question of how to improve access to +care and it seems like bit of attention + + align:start position:0% +care and it seems like bit of attention + + + align:start position:0% +care and it seems like bit of attention +there so Largemouth actually asked a + + align:start position:0% +there so Largemouth actually asked a + + + align:start position:0% +there so Largemouth actually asked a +question about that I don't know if + + align:start position:0% +question about that I don't know if + + + align:start position:0% +question about that I don't know if +she's listening now or is just going to + + align:start position:0% +she's listening now or is just going to + + + align:start position:0% +she's listening now or is just going to +hear this later but + + align:start position:0% +hear this later but + + + align:start position:0% +hear this later but +um + + align:start position:0% +um + + + align:start position:0% +um +this is a a problem that I've again I'm + + align:start position:0% +this is a a problem that I've again I'm + + + align:start position:0% +this is a a problem that I've again I'm +going to use a little uh political + + align:start position:0% +going to use a little uh political + + + align:start position:0% +going to use a little uh political +economic notion here + + align:start position:0% +economic notion here + + + align:start position:0% +economic notion here +the the times I've heard that question + + align:start position:0% +the the times I've heard that question + + + align:start position:0% +the the times I've heard that question +most has not been in settings of great + + align:start position:0% +most has not been in settings of great + + + align:start position:0% +most has not been in settings of great +rural privation from our patients it's + + align:start position:0% +rural privation from our patients it's + + + align:start position:0% +rural privation from our patients it's +more from our staff interestingly right + + align:start position:0% +more from our staff interestingly right + + + align:start position:0% +more from our staff interestingly right +um and so the primary again this is a + + align:start position:0% +um and so the primary again this is a + + + align:start position:0% +um and so the primary again this is a +gross generalization but I think it's + + align:start position:0% +gross generalization but I think it's + + + align:start position:0% +gross generalization but I think it's +true nonetheless gross meaning Grand + + align:start position:0% +true nonetheless gross meaning Grand + + + align:start position:0% +true nonetheless gross meaning Grand +that + + align:start position:0% +that + + + align:start position:0% +that +the privacy concerns are tightly time + + align:start position:0% +the privacy concerns are tightly time + + + align:start position:0% +the privacy concerns are tightly time +tied to class aspirations right so a lot + + align:start position:0% +tied to class aspirations right so a lot + + + align:start position:0% +tied to class aspirations right so a lot +of the people were serving AIDS is kind + + align:start position:0% +of the people were serving AIDS is kind + + + align:start position:0% +of the people were serving AIDS is kind +of just the latest problem to show up in + + align:start position:0% +of just the latest problem to show up in + + + align:start position:0% +of just the latest problem to show up in +their lives you know some of the people + + align:start position:0% +their lives you know some of the people + + + align:start position:0% +their lives you know some of the people +you've met in reality and their primary + + align:start position:0% +you've met in reality and their primary + + + align:start position:0% +you've met in reality and their primary +concern is access back to the second + + align:start position:0% +concern is access back to the second + + + align:start position:0% +concern is access back to the second +part of her question is how can we get + + align:start position:0% +part of her question is how can we get + + + align:start position:0% +part of her question is how can we get +care I remember being told in uh again + + align:start position:0% +care I remember being told in uh again + + + align:start position:0% +care I remember being told in uh again +here that when you go to Rwanda there's + + align:start position:0% +here that when you go to Rwanda there's + + + align:start position:0% +here that when you go to Rwanda there's +so much secrecy no one's going to know + + align:start position:0% +so much secrecy no one's going to know + + + align:start position:0% +so much secrecy no one's going to know +their status or tell you their status I + + align:start position:0% +their status or tell you their status I + + + align:start position:0% +their status or tell you their status I +went in 2004 out to community meetings + + align:start position:0% +went in 2004 out to community meetings + + + align:start position:0% +went in 2004 out to community meetings +the year before we started some months + + align:start position:0% +the year before we started some months + + + align:start position:0% +the year before we started some months +before in a village where you know in + + align:start position:0% +before in a village where you know in + + + align:start position:0% +before in a village where you know in +the city this might happen in the + + align:start position:0% +the city this might happen in the + + + align:start position:0% +the city this might happen in the +village in the rural area say well how + + align:start position:0% +village in the rural area say well how + + + align:start position:0% +village in the rural area say well how +many of you have HIV and it all rest + + align:start position:0% +many of you have HIV and it all rest + + + align:start position:0% +many of you have HIV and it all rest +their hand and how many of you know your + + align:start position:0% +their hand and how many of you know your + + + align:start position:0% +their hand and how many of you know your +C4 count they'd be going 262 84. and + + align:start position:0% +C4 count they'd be going 262 84. and + + + align:start position:0% +C4 count they'd be going 262 84. and +these are very public for us you know + + align:start position:0% +these are very public for us you know + + + align:start position:0% +these are very public for us you know +and so I would just say we have to be + + align:start position:0% +and so I would just say we have to be + + + align:start position:0% +and so I would just say we have to be +very careful to respect that question + + align:start position:0% +very careful to respect that question + + + align:start position:0% +very careful to respect that question +how to protect privacy + + align:start position:0% +how to protect privacy + + + align:start position:0% +how to protect privacy +but it's still not fundamentally related + + align:start position:0% +but it's still not fundamentally related + + + align:start position:0% +but it's still not fundamentally related +to it's not the on the top five uh + + align:start position:0% +to it's not the on the top five uh + + + align:start position:0% +to it's not the on the top five uh +barriers back to your question uh to + + align:start position:0% +barriers back to your question uh to + + + align:start position:0% +barriers back to your question uh to +access in the rural regions uh oh even I + + align:start position:0% +access in the rural regions uh oh even I + + + align:start position:0% +access in the rural regions uh oh even I +think in the urban regions it's in the + + align:start position:0% +think in the urban regions it's in the + + + align:start position:0% +think in the urban regions it's in the +maybe top 15 as a barrier itself now + + align:start position:0% +maybe top 15 as a barrier itself now + + + align:start position:0% +maybe top 15 as a barrier itself now +that doesn't mean we don't have an + + align:start position:0% +that doesn't mean we don't have an + + + align:start position:0% +that doesn't mean we don't have an +obligation to take this very seriously + + align:start position:0% +obligation to take this very seriously + + + align:start position:0% +obligation to take this very seriously +as I know you and your team have with a + + align:start position:0% +as I know you and your team have with a + + + align:start position:0% +as I know you and your team have with a +unique patient identifiers and sign-in + + align:start position:0% +unique patient identifiers and sign-in + + + align:start position:0% +unique patient identifiers and sign-in +code so you can't log on the system in + + align:start position:0% +code so you can't log on the system in + + + align:start position:0% +code so you can't log on the system in +Haiti unless you use your user ID just + + align:start position:0% +Haiti unless you use your user ID just + + + align:start position:0% +Haiti unless you use your user ID just +like at the Brigham you know and so your + + align:start position:0% +like at the Brigham you know and so your + + + align:start position:0% +like at the Brigham you know and so your +electronic fingerprint if you're going + + align:start position:0% +electronic fingerprint if you're going + + + align:start position:0% +electronic fingerprint if you're going +into someone's medical record is there + + align:start position:0% +into someone's medical record is there + + + align:start position:0% +into someone's medical record is there +but again I think that's just uh that + + align:start position:0% +but again I think that's just uh that + + + align:start position:0% +but again I think that's just uh that +that's us being responsible + + align:start position:0% +that's us being responsible + + + align:start position:0% +that's us being responsible +um to you know to have not a double + + align:start position:0% +um to you know to have not a double + + + align:start position:0% +um to you know to have not a double +standard care in Haiti uh and Rwanda + + align:start position:0% +standard care in Haiti uh and Rwanda + + + align:start position:0% +standard care in Haiti uh and Rwanda +Malawi et cetera but again that the + + align:start position:0% +Malawi et cetera but again that the + + + align:start position:0% +Malawi et cetera but again that the +concern comes largely from has come more + + align:start position:0% +concern comes largely from has come more + + + align:start position:0% +concern comes largely from has come more +from our employees than who also I mean + + align:start position:0% +from our employees than who also I mean + + + align:start position:0% +from our employees than who also I mean +our employees with HIV than from the + + align:start position:0% +our employees with HIV than from the + + + align:start position:0% +our employees with HIV than from the +patients who we've been seeing in these + + align:start position:0% +patients who we've been seeing in these + + + align:start position:0% +patients who we've been seeing in these +first years and I think that's an + + align:start position:0% +first years and I think that's an + + + align:start position:0% +first years and I think that's an +interesting I mean an anthropologist + + align:start position:0% +interesting I mean an anthropologist + + + align:start position:0% +interesting I mean an anthropologist +ought to go in and talk about how some + + align:start position:0% +ought to go in and talk about how some + + + align:start position:0% +ought to go in and talk about how some +people have these aspirations where + + align:start position:0% +people have these aspirations where + + + align:start position:0% +people have these aspirations where +suddenly for the first time in their + + align:start position:0% +suddenly for the first time in their + + + align:start position:0% +suddenly for the first time in their +lives HIV comes along to spoil their + + align:start position:0% +lives HIV comes along to spoil their + + + align:start position:0% +lives HIV comes along to spoil their +aspirations whereas other people have + + align:start position:0% +aspirations whereas other people have + + + align:start position:0% +aspirations whereas other people have +been living a lifetime of disappointment + + align:start position:0% +been living a lifetime of disappointment + + + align:start position:0% +been living a lifetime of disappointment +and you know that again this is the + + align:start position:0% +and you know that again this is the + + + align:start position:0% +and you know that again this is the +latest thing to come in and spoil + + align:start position:0% +latest thing to come in and spoil + + + align:start position:0% +latest thing to come in and spoil +aspirations that were set though to + + align:start position:0% +aspirations that were set though to + + + align:start position:0% +aspirations that were set though to +start with because of so many so much + + align:start position:0% +start with because of so many so much + + + align:start position:0% +start with because of so many so much +unfairness again lack of access to + + align:start position:0% +unfairness again lack of access to + + + align:start position:0% +unfairness again lack of access to +school primary even Primary School to a + + align:start position:0% +school primary even Primary School to a + + + align:start position:0% +school primary even Primary School to a +job to family planning to you know on + + align:start position:0% +job to family planning to you know on + + + align:start position:0% +job to family planning to you know on +and on the list codes + + align:start position:0% + + + + align:start position:0% + +so just to open it up to other questions + + align:start position:0% + + + + align:start position:0% + +yeah I mean I please yes sir there's a + + align:start position:0% +yeah I mean I please yes sir there's a + + + align:start position:0% +yeah I mean I please yes sir there's a +snake also from the School of Public + + align:start position:0% +snake also from the School of Public + + + align:start position:0% +snake also from the School of Public +Health so I've got the question + + align:start position:0% +Health so I've got the question + + + align:start position:0% +Health so I've got the question +um to you about uh using the human + + align:start position:0% +um to you about uh using the human + + + align:start position:0% +um to you about uh using the human +rights framework yeah in what you do and + + align:start position:0% +rights framework yeah in what you do and + + + align:start position:0% +rights framework yeah in what you do and +the status of Technology within that so + + align:start position:0% +the status of Technology within that so + + + align:start position:0% +the status of Technology within that so +given the rise of mhealth Kelly medicine + + align:start position:0% +given the rise of mhealth Kelly medicine + + + align:start position:0% +given the rise of mhealth Kelly medicine +um you too with the telemedicine and + + align:start position:0% + + + + align:start position:0% + +um uh do you think that it is inherent + + align:start position:0% +um uh do you think that it is inherent + + + align:start position:0% +um uh do you think that it is inherent +in the right to health technology is + + align:start position:0% +in the right to health technology is + + + align:start position:0% +in the right to health technology is +included within that or do you think + + align:start position:0% +included within that or do you think + + + align:start position:0% +included within that or do you think +there is an on-the-ground tangible + + align:start position:0% +there is an on-the-ground tangible + + + align:start position:0% +there is an on-the-ground tangible +important role the separate right the + + align:start position:0% +important role the separate right the + + + align:start position:0% +important role the separate right the +right to enjoy the benefits of + + align:start position:0% +right to enjoy the benefits of + + + align:start position:0% +right to enjoy the benefits of +scientific progress what do you think + + align:start position:0% +scientific progress what do you think + + + align:start position:0% +scientific progress what do you think +that's now that I have given that + + align:start position:0% +that's now that I have given that + + + align:start position:0% +that's now that I have given that +technology is so Central to help today + + align:start position:0% +technology is so Central to help today + + + align:start position:0% +technology is so Central to help today +well I mean I would I would say that it + + align:start position:0% +well I mean I would I would say that it + + + align:start position:0% +well I mean I would I would say that it +is possible to exploit multiple + + align:start position:0% +is possible to exploit multiple + + + align:start position:0% +is possible to exploit multiple +Frameworks at the same time and I I'm + + align:start position:0% +Frameworks at the same time and I I'm + + + align:start position:0% +Frameworks at the same time and I I'm +also kind of a pro at that right so + + align:start position:0% +also kind of a pro at that right so + + + align:start position:0% +also kind of a pro at that right so +three big Frameworks when the right + + align:start position:0% +three big Frameworks when the right + + + align:start position:0% +three big Frameworks when the right +space framework which I find very useful + + align:start position:0% +space framework which I find very useful + + + align:start position:0% +space framework which I find very useful +uh another would be the public goods for + + align:start position:0% +uh another would be the public goods for + + + align:start position:0% +uh another would be the public goods for +public health framework which the public + + align:start position:0% +public health framework which the public + + + align:start position:0% +public health framework which the public +health people as you know develop this + + align:start position:0% +health people as you know develop this + + + align:start position:0% +health people as you know develop this +they're comfortable with it it doesn't + + align:start position:0% +they're comfortable with it it doesn't + + + align:start position:0% +they're comfortable with it it doesn't +you'll find a lot of people in public + + align:start position:0% +you'll find a lot of people in public + + + align:start position:0% +you'll find a lot of people in public +health who are uncomfortable with the + + align:start position:0% +health who are uncomfortable with the + + + align:start position:0% +health who are uncomfortable with the +right space probes they think it sounds + + align:start position:0% +right space probes they think it sounds + + + align:start position:0% +right space probes they think it sounds +real or you know I get I get that and + + align:start position:0% +real or you know I get I get that and + + + align:start position:0% +real or you know I get I get that and +then third how are we gonna which is + + align:start position:0% +then third how are we gonna which is + + + align:start position:0% +then third how are we gonna which is +kind of the economics development + + align:start position:0% +kind of the economics development + + + align:start position:0% +kind of the economics development +framework how will we break the cycle of + + align:start position:0% +framework how will we break the cycle of + + + align:start position:0% +framework how will we break the cycle of +poverty disease if we don't invest in + + align:start position:0% +poverty disease if we don't invest in + + + align:start position:0% +poverty disease if we don't invest in +these new technologies so I think either + + align:start position:0% +these new technologies so I think either + + + align:start position:0% +these new technologies so I think either +way you look at it + + align:start position:0% +way you look at it + + + align:start position:0% +way you look at it +these Frameworks lead to the same thing + + align:start position:0% +these Frameworks lead to the same thing + + + align:start position:0% +these Frameworks lead to the same thing +which is valuing + + align:start position:0% +which is valuing + + + align:start position:0% +which is valuing +uh scientific progress as the basis of a + + align:start position:0% +uh scientific progress as the basis of a + + + align:start position:0% +uh scientific progress as the basis of a +lot of these interventions I think + + align:start position:0% +lot of these interventions I think + + + align:start position:0% +lot of these interventions I think +that's a healthy thing to do so whether + + align:start position:0% +that's a healthy thing to do so whether + + + align:start position:0% +that's a healthy thing to do so whether +we say well you know just the right to + + align:start position:0% +we say well you know just the right to + + + align:start position:0% +we say well you know just the right to +Health Care will drag in the right to + + align:start position:0% +Health Care will drag in the right to + + + align:start position:0% +Health Care will drag in the right to +technological advance I think that's + + align:start position:0% +technological advance I think that's + + + align:start position:0% +technological advance I think that's +true because all of the Technologies + + align:start position:0% +true because all of the Technologies + + + align:start position:0% +true because all of the Technologies +we're talking about that I've spoken + + align:start position:0% +we're talking about that I've spoken + + + align:start position:0% +we're talking about that I've spoken +about today each of them is a post-mid + + align:start position:0% +about today each of them is a post-mid + + + align:start position:0% +about today each of them is a post-mid +20th century development antivirus + + align:start position:0% +20th century development antivirus + + + align:start position:0% +20th century development antivirus +antibiotics Diagnostics and the maladies + + align:start position:0% +antibiotics Diagnostics and the maladies + + + align:start position:0% +antibiotics Diagnostics and the maladies +themselves right they've changed at the + + align:start position:0% +themselves right they've changed at the + + + align:start position:0% +themselves right they've changed at the +genetic level drug resistant TV drug + + align:start position:0% +genetic level drug resistant TV drug + + + align:start position:0% +genetic level drug resistant TV drug +resistant HIV drug assistance staph + + align:start position:0% +resistant HIV drug assistance staph + + + align:start position:0% +resistant HIV drug assistance staph +aureus blah blah blah they've all + + align:start position:0% +aureus blah blah blah they've all + + + align:start position:0% +aureus blah blah blah they've all +um I guess blah blah is not really good + + align:start position:0% +um I guess blah blah is not really good + + + align:start position:0% +um I guess blah blah is not really good +to broadcast internationally you know + + align:start position:0% +to broadcast internationally you know + + + align:start position:0% +to broadcast internationally you know +what I mean so I think that that model + + align:start position:0% +what I mean so I think that that model + + + align:start position:0% +what I mean so I think that that model +is still robust say look if you want to + + align:start position:0% +is still robust say look if you want to + + + align:start position:0% +is still robust say look if you want to +if you want to talk about the right to + + align:start position:0% +if you want to talk about the right to + + + align:start position:0% +if you want to talk about the right to +health care you're going to have to talk + + align:start position:0% +health care you're going to have to talk + + + align:start position:0% +health care you're going to have to talk +about the right to access a new + + align:start position:0% +about the right to access a new + + + align:start position:0% +about the right to access a new +technology now at the same time does it + + align:start position:0% +technology now at the same time does it + + + align:start position:0% +technology now at the same time does it +weaken or strengthen the argument + + align:start position:0% +weaken or strengthen the argument + + + align:start position:0% +weaken or strengthen the argument +because this is really about an argument + + align:start position:0% +because this is really about an argument + + + align:start position:0% +because this is really about an argument +right a pitch for using these + + align:start position:0% +right a pitch for using these + + + align:start position:0% +right a pitch for using these +developments to promote health and + + align:start position:0% +developments to promote health and + + + align:start position:0% +developments to promote health and +well-being among people have been cut + + align:start position:0% +well-being among people have been cut + + + align:start position:0% +well-being among people have been cut +out of scientific progress I think it's + + align:start position:0% +out of scientific progress I think it's + + + align:start position:0% +out of scientific progress I think it's +also helpful to have people think about + + align:start position:0% +also helpful to have people think about + + + align:start position:0% +also helpful to have people think about +the digital divide you know what the + + align:start position:0% +the digital divide you know what the + + + align:start position:0% +the digital divide you know what the +cost of not having access to these new + + align:start position:0% +cost of not having access to these new + + + align:start position:0% +cost of not having access to these new +technologies is in a right space + + align:start position:0% +technologies is in a right space + + + align:start position:0% +technologies is in a right space +framework as well I think it's + + align:start position:0% +framework as well I think it's + + + align:start position:0% +framework as well I think it's +complementary rather than corrosive or + + align:start position:0% +complementary rather than corrosive or + + + align:start position:0% +complementary rather than corrosive or +um so I would actually say that we're + + align:start position:0% +um so I would actually say that we're + + + align:start position:0% +um so I would actually say that we're +working together like if we get the I.T + + align:start position:0% +working together like if we get the I.T + + + align:start position:0% +working together like if we get the I.T +nerds together with us as the health + + align:start position:0% +nerds together with us as the health + + + align:start position:0% +nerds together with us as the health +providers it's a very powerful thing + + align:start position:0% +providers it's a very powerful thing + + + align:start position:0% +providers it's a very powerful thing +itns you could move for one or two more + + align:start position:0% +itns you could move for one or two more + + + align:start position:0% +itns you could move for one or two more +questions + + align:start position:0% +questions + + + align:start position:0% +questions +am I am I yes please and then can we + + align:start position:0% +am I am I yes please and then can we + + + align:start position:0% +am I am I yes please and then can we +just at least take these three because + + align:start position:0% +just at least take these three because + + + align:start position:0% +just at least take these three because +they're all in a little triangle and I + + align:start position:0% +they're all in a little triangle and I + + + align:start position:0% +they're all in a little triangle and I +said so + + align:start position:0% +said so + + + align:start position:0% +said so +I'll try to speed it up + + align:start position:0% +I'll try to speed it up + + + align:start position:0% +I'll try to speed it up +I'm Gene Gilman with the security + + align:start position:0% +I'm Gene Gilman with the security + + + align:start position:0% +I'm Gene Gilman with the security +studies program at MIT and I have a + + align:start position:0% +studies program at MIT and I have a + + + align:start position:0% +studies program at MIT and I have a +question about surveillance and how do + + align:start position:0% +question about surveillance and how do + + + align:start position:0% +question about surveillance and how do +you think about certain disease + + align:start position:0% +you think about certain disease + + + align:start position:0% +you think about certain disease +surveillance yeah we've had a great + + align:start position:0% +surveillance yeah we've had a great + + + align:start position:0% +surveillance yeah we've had a great +controversy about h5n1 and that + + align:start position:0% +controversy about h5n1 and that + + + align:start position:0% +controversy about h5n1 and that +researches at least the Wisconsin aspect + + align:start position:0% +researches at least the Wisconsin aspect + + + align:start position:0% +researches at least the Wisconsin aspect +of it is to be published in nature in + + align:start position:0% +of it is to be published in nature in + + + align:start position:0% +of it is to be published in nature in +Italy and the Science magazine will also + + align:start position:0% +Italy and the Science magazine will also + + + align:start position:0% +Italy and the Science magazine will also +be published in the rottenham result and + + align:start position:0% +be published in the rottenham result and + + + align:start position:0% +be published in the rottenham result and +both of the + + align:start position:0% +both of the + + + align:start position:0% +both of the +academies of researchers have said that + + align:start position:0% +academies of researchers have said that + + + align:start position:0% +academies of researchers have said that +they're doing this research which is to + + align:start position:0% +they're doing this research which is to + + + align:start position:0% +they're doing this research which is to +actually jump ahead of nature that would + + align:start position:0% +actually jump ahead of nature that would + + + align:start position:0% +actually jump ahead of nature that would +host + + align:start position:0% +host + + + align:start position:0% +host +host responses to avian flu h5n1 they + + align:start position:0% +host responses to avian flu h5n1 they + + + align:start position:0% +host responses to avian flu h5n1 they +both said that what they want to do is + + align:start position:0% +both said that what they want to do is + + + align:start position:0% +both said that what they want to do is +create mechanisms for improved + + align:start position:0% +create mechanisms for improved + + + align:start position:0% +create mechanisms for improved +surveillance so I'm asking you about + + align:start position:0% +surveillance so I'm asking you about + + + align:start position:0% +surveillance so I'm asking you about +surveillance because there are these + + align:start position:0% +surveillance because there are these + + + align:start position:0% +surveillance because there are these +platforms that you have established and + + align:start position:0% +platforms that you have established and + + + align:start position:0% +platforms that you have established and +that you're looking at are they also + + align:start position:0% +that you're looking at are they also + + + align:start position:0% +that you're looking at are they also +good modalities for for surveillance + + align:start position:0% +good modalities for for surveillance + + + align:start position:0% +good modalities for for surveillance +which is a huge problem if you look at + + align:start position:0% +which is a huge problem if you look at + + + align:start position:0% +which is a huge problem if you look at +Avian Influenza + + align:start position:0% +Avian Influenza + + + align:start position:0% +Avian Influenza +um and then I guess + + align:start position:0% +um and then I guess + + + align:start position:0% +um and then I guess +um I think behind behind that question I + + align:start position:0% +um I think behind behind that question I + + + align:start position:0% +um I think behind behind that question I +think would it's going to be a larger + + align:start position:0% +think would it's going to be a larger + + + align:start position:0% +think would it's going to be a larger +question about + + align:start position:0% +question about + + + align:start position:0% +question about +um which has already been echoed here is + + align:start position:0% +um which has already been echoed here is + + + align:start position:0% +um which has already been echoed here is +our are we bringing people into the 21st + + align:start position:0% +our are we bringing people into the 21st + + + align:start position:0% +our are we bringing people into the 21st +century and are this is very futuristic + + align:start position:0% +century and are this is very futuristic + + + align:start position:0% +century and are this is very futuristic +this is a true called in question please + + align:start position:0% + + + + align:start position:0% + +um no I just I I guess it's this this + + align:start position:0% +um no I just I I guess it's this this + + + align:start position:0% +um no I just I I guess it's this this +whole issue of where is basic science + + align:start position:0% +whole issue of where is basic science + + + align:start position:0% +whole issue of where is basic science +relative to what you're doing and I know + + align:start position:0% +relative to what you're doing and I know + + + align:start position:0% +relative to what you're doing and I know +you think of this in the treatment mode + + align:start position:0% +you think of this in the treatment mode + + + align:start position:0% +you think of this in the treatment mode +yeah the way people are looking at it + + align:start position:0% +yeah the way people are looking at it + + + align:start position:0% +yeah the way people are looking at it +now is there a surveillance level but I + + align:start position:0% +now is there a surveillance level but I + + + align:start position:0% +now is there a surveillance level but I +can throw you the general questions + + align:start position:0% +can throw you the general questions + + + align:start position:0% +can throw you the general questions +where is the link between basic science + + align:start position:0% +where is the link between basic science + + + align:start position:0% +where is the link between basic science +and treatment as it impacts your project + + align:start position:0% +and treatment as it impacts your project + + + align:start position:0% +and treatment as it impacts your project +yeah can I start with the second part + + align:start position:0% +yeah can I start with the second part + + + align:start position:0% +yeah can I start with the second part +and go back to surveillance because you + + align:start position:0% +and go back to surveillance because you + + + align:start position:0% +and go back to surveillance because you +know there are multiple regimens of + + align:start position:0% +know there are multiple regimens of + + + align:start position:0% +know there are multiple regimens of +surveillance as you well know but back + + align:start position:0% +surveillance as you well know but back + + + align:start position:0% +surveillance as you well know but back +to the the basic science question I + + align:start position:0% +to the the basic science question I + + + align:start position:0% +to the the basic science question I +would argue that + + align:start position:0% +would argue that + + + align:start position:0% +would argue that +we in no example is more powerful than + + align:start position:0% +we in no example is more powerful than + + + align:start position:0% +we in no example is more powerful than +AIDS and in 30 years + + align:start position:0% +AIDS and in 30 years + + + align:start position:0% +AIDS and in 30 years +only 30 years that you + + align:start position:0% +only 30 years that you + + + align:start position:0% +only 30 years that you +can go from a new + + align:start position:0% +can go from a new + + + align:start position:0% +can go from a new +uh syndrome and you know at least in + + align:start position:0% +uh syndrome and you know at least in + + + align:start position:0% +uh syndrome and you know at least in +this part of the world and certainly + + align:start position:0% +this part of the world and certainly + + + align:start position:0% +this part of the world and certainly +newly described identify the pathogen + + align:start position:0% +newly described identify the pathogen + + + align:start position:0% +newly described identify the pathogen +learn how to Stage diagnose and Stage + + align:start position:0% +learn how to Stage diagnose and Stage + + + align:start position:0% +learn how to Stage diagnose and Stage +the disease with great reliability + + align:start position:0% +the disease with great reliability + + + align:start position:0% +the disease with great reliability +and then have a fairly reasonable + + align:start position:0% +and then have a fairly reasonable + + + align:start position:0% +and then have a fairly reasonable +treatment regimen developed uh + + align:start position:0% +treatment regimen developed uh + + + align:start position:0% +treatment regimen developed uh +suppressive chronic but still pretty + + align:start position:0% +suppressive chronic but still pretty + + + align:start position:0% +suppressive chronic but still pretty +pretty good I mean look at certainly + + align:start position:0% +pretty good I mean look at certainly + + + align:start position:0% +pretty good I mean look at certainly +looks good to me as a doctor + + align:start position:0% +looks good to me as a doctor + + + align:start position:0% +looks good to me as a doctor +all that has happened in 30 years and + + align:start position:0% +all that has happened in 30 years and + + + align:start position:0% +all that has happened in 30 years and +it's all database I mean it's all built + + align:start position:0% +it's all database I mean it's all built + + + align:start position:0% +it's all database I mean it's all built +on basic science laboratory research the + + align:start position:0% +on basic science laboratory research the + + + align:start position:0% +on basic science laboratory research the +legit the Therapeutics the Diagnostics + + align:start position:0% +legit the Therapeutics the Diagnostics + + + align:start position:0% +legit the Therapeutics the Diagnostics +so I think that is a pretty powerful + + align:start position:0% +so I think that is a pretty powerful + + + align:start position:0% +so I think that is a pretty powerful +example of how you can link uh + + align:start position:0% +example of how you can link uh + + + align:start position:0% +example of how you can link uh +scientific development to a great need + + align:start position:0% +scientific development to a great need + + + align:start position:0% +scientific development to a great need +again I mentioned already the leading + + align:start position:0% +again I mentioned already the leading + + + align:start position:0% +again I mentioned already the leading +infectious killer of young adults in the + + align:start position:0% +infectious killer of young adults in the + + + align:start position:0% +infectious killer of young adults in the +world and the huge killer of children as + + align:start position:0% +world and the huge killer of children as + + + align:start position:0% +world and the huge killer of children as +well and elderly people I mean it's just + + align:start position:0% +well and elderly people I mean it's just + + + align:start position:0% +well and elderly people I mean it's just +the and then there's the indirect cost + + align:start position:0% +the and then there's the indirect cost + + + align:start position:0% +the and then there's the indirect cost +to the elderly and the um who are not + + align:start position:0% +to the elderly and the um who are not + + + align:start position:0% +to the elderly and the um who are not +infected but are affected so I think + + align:start position:0% +infected but are affected so I think + + + align:start position:0% +infected but are affected so I think +it's a good story for science for basic + + align:start position:0% +it's a good story for science for basic + + + align:start position:0% +it's a good story for science for basic +science and that it also gets back to + + align:start position:0% +science and that it also gets back to + + + align:start position:0% +science and that it also gets back to +the surveillance question because I + + align:start position:0% +the surveillance question because I + + + align:start position:0% +the surveillance question because I +remember you know + + align:start position:0% +remember you know + + + align:start position:0% +remember you know +um some of the things indeed I wrote + + align:start position:0% +um some of the things indeed I wrote + + + align:start position:0% +um some of the things indeed I wrote +about this in the 80s + + align:start position:0% +about this in the 80s + + + align:start position:0% +about this in the 80s +about the negative aspects of + + align:start position:0% +about the negative aspects of + + + align:start position:0% +about the negative aspects of +surveillance of HIV and there are a lot + + align:start position:0% +surveillance of HIV and there are a lot + + + align:start position:0% +surveillance of HIV and there are a lot +of people writing about that in 80s + + align:start position:0% +of people writing about that in 80s + + + align:start position:0% +of people writing about that in 80s +because you really you know we really + + align:start position:0% +because you really you know we really + + + align:start position:0% +because you really you know we really +didn't have a good therapeutic strategy + + align:start position:0% +didn't have a good therapeutic strategy + + + align:start position:0% +didn't have a good therapeutic strategy +then + + align:start position:0% +then + + + align:start position:0% +then +but we did have the people did have the + + align:start position:0% +but we did have the people did have the + + + align:start position:0% +but we did have the people did have the +ability to discriminate against people + + align:start position:0% +ability to discriminate against people + + + align:start position:0% +ability to discriminate against people +with living or living with HIV in the + + align:start position:0% +with living or living with HIV in the + + + align:start position:0% +with living or living with HIV in the +workplace and in housing questions in + + align:start position:0% +workplace and in housing questions in + + + align:start position:0% +workplace and in housing questions in +this country and in all kinds of ways in + + align:start position:0% +this country and in all kinds of ways in + + + align:start position:0% +this country and in all kinds of ways in +other settings too so the negative + + align:start position:0% +other settings too so the negative + + + align:start position:0% +other settings too so the negative +aspects of surveillance are also out + + align:start position:0% +aspects of surveillance are also out + + + align:start position:0% +aspects of surveillance are also out +there I don't know which one you were + + align:start position:0% +there I don't know which one you were + + + align:start position:0% +there I don't know which one you were +leaning on Gene but in terms of + + align:start position:0% +leaning on Gene but in terms of + + + align:start position:0% +leaning on Gene but in terms of +surveillance to serve as important as + + align:start position:0% +surveillance to serve as important as + + + align:start position:0% +surveillance to serve as important as +opposed to to discipline + + align:start position:0% +opposed to to discipline + + + align:start position:0% +opposed to to discipline +um these platforms offer great potential + + align:start position:0% +um these platforms offer great potential + + + align:start position:0% +um these platforms offer great potential +and well I think one of the again one of + + align:start position:0% +and well I think one of the again one of + + + align:start position:0% +and well I think one of the again one of +the smart things for us to do to show + + align:start position:0% +the smart things for us to do to show + + + align:start position:0% +the smart things for us to do to show +how surveillance of an epidemic is a + + align:start position:0% +how surveillance of an epidemic is a + + + align:start position:0% +how surveillance of an epidemic is a +good thing is to link that to service + + align:start position:0% +good thing is to link that to service + + + align:start position:0% +good thing is to link that to service +like with cholera do you want to count + + align:start position:0% +like with cholera do you want to count + + + align:start position:0% +like with cholera do you want to count +call our victims or do we want to + + align:start position:0% +call our victims or do we want to + + + align:start position:0% +call our victims or do we want to +eradicate cholera from the island of + + align:start position:0% +eradicate cholera from the island of + + + align:start position:0% +eradicate cholera from the island of +Hispaniola and develop a stockpile for + + align:start position:0% +Hispaniola and develop a stockpile for + + + align:start position:0% +Hispaniola and develop a stockpile for +the world we want the latter and we want + + align:start position:0% +the world we want the latter and we want + + + align:start position:0% +the world we want the latter and we want +to count cholera cases so that we can + + align:start position:0% +to count cholera cases so that we can + + + align:start position:0% +to count cholera cases so that we can +build better budgets and better + + align:start position:0% +build better budgets and better + + + align:start position:0% +build better budgets and better +interventions and raise resources to + + align:start position:0% +interventions and raise resources to + + + align:start position:0% +interventions and raise resources to +save lives but we also want to do it uh + + align:start position:0% +save lives but we also want to do it uh + + + align:start position:0% +save lives but we also want to do it uh +you know to eradicate disease so for to + + align:start position:0% +you know to eradicate disease so for to + + + align:start position:0% +you know to eradicate disease so for to +the extent I'm back to the general Point + + align:start position:0% +the extent I'm back to the general Point + + + align:start position:0% +the extent I'm back to the general Point +here about surveillance stop looking at + + align:start position:0% +here about surveillance stop looking at + + + align:start position:0% +here about surveillance stop looking at +your cell phone watch a good time + + align:start position:0% +your cell phone watch a good time + + + align:start position:0% +your cell phone watch a good time +so you know I think the promise of good + + align:start position:0% +so you know I think the promise of good + + + align:start position:0% +so you know I think the promise of good +surveillance uh is is it comes out of + + align:start position:0% +surveillance uh is is it comes out of + + + align:start position:0% +surveillance uh is is it comes out of +these platforms and that the net good is + + align:start position:0% +these platforms and that the net good is + + + align:start position:0% +these platforms and that the net good is +going to be huge we also just have to + + align:start position:0% +going to be huge we also just have to + + + align:start position:0% +going to be huge we also just have to +link that back to the rights questions + + align:start position:0% +link that back to the rights questions + + + align:start position:0% +link that back to the rights questions +that were mentioned already and the + + align:start position:0% +that were mentioned already and the + + + align:start position:0% +that were mentioned already and the +right of it to access is the biggest one + + align:start position:0% +right of it to access is the biggest one + + + align:start position:0% +right of it to access is the biggest one +among them + + align:start position:0% +among them + + + align:start position:0% +among them +so we've actually got um like five + + align:start position:0% +so we've actually got um like five + + + align:start position:0% +so we've actually got um like five +minutes and there is a class after this + + align:start position:0% +minutes and there is a class after this + + + align:start position:0% +minutes and there is a class after this +so I think what I'll do is just a quick + + align:start position:0% +so I think what I'll do is just a quick + + + align:start position:0% +so I think what I'll do is just a quick +announcement and then one more question + + align:start position:0% +announcement and then one more question + + + align:start position:0% +announcement and then one more question +so just for next week for the class um + + align:start position:0% +so just for next week for the class um + + + align:start position:0% +so just for next week for the class um +we actually have the class project + + align:start position:0% +we actually have the class project + + + align:start position:0% +we actually have the class project +presentation so we're looking forward to + + align:start position:0% +presentation so we're looking forward to + + + align:start position:0% +presentation so we're looking forward to +that and other people are interested in + + align:start position:0% +that and other people are interested in + + + align:start position:0% +that and other people are interested in +welcome to come and join that + + align:start position:0% +welcome to come and join that + + + align:start position:0% +welcome to come and join that +um uh as I said there is another class + + align:start position:0% +um uh as I said there is another class + + + align:start position:0% +um uh as I said there is another class +coming in so in the Buckeyes we need to + + align:start position:0% +coming in so in the Buckeyes we need to + + + align:start position:0% +coming in so in the Buckeyes we need to +and to leave the room but everything + + align:start position:0% +and to leave the room but everything + + + align:start position:0% +and to leave the room but everything +sounds like to use that last time for at + + align:start position:0% +sounds like to use that last time for at + + + align:start position:0% +sounds like to use that last time for at +least one more question everything that + + align:start position:0% +least one more question everything that + + + align:start position:0% +least one more question everything that +sounds better with the Scottish Burr + + align:start position:0% +sounds better with the Scottish Burr + + + align:start position:0% +sounds better with the Scottish Burr +like get out + + align:start position:0% + + + + align:start position:0% + +and then I'll stick around outside by + + align:start position:0% +and then I'll stick around outside by + + + align:start position:0% +and then I'll stick around outside by +the way if I might so sorry + + align:start position:0% +the way if I might so sorry + + + align:start position:0% +the way if I might so sorry +I'm curious if there was an optimal mix + + align:start position:0% +I'm curious if there was an optimal mix + + + align:start position:0% +I'm curious if there was an optimal mix +of the number of participants in the + + align:start position:0% +of the number of participants in the + + + align:start position:0% +of the number of participants in the +process so the physician the first the + + align:start position:0% +process so the physician the first the + + + align:start position:0% +process so the physician the first the +community healthcare presentation that's + + align:start position:0% +community healthcare presentation that's + + + align:start position:0% +community healthcare presentation that's +a great question is there where where + + align:start position:0% +a great question is there where where + + + align:start position:0% +a great question is there where where +the the software do you try to engage + + align:start position:0% +the the software do you try to engage + + + align:start position:0% +the the software do you try to engage +the whole Community because it's a + + align:start position:0% +the whole Community because it's a + + + align:start position:0% +the whole Community because it's a +community-based pro if you engage the + + align:start position:0% +community-based pro if you engage the + + + align:start position:0% +community-based pro if you engage the +whole community + + align:start position:0% +whole community + + + align:start position:0% +whole community +where does it stop before it comes + + align:start position:0% +where does it stop before it comes + + + align:start position:0% +where does it stop before it comes +becomes like an issue like here where + + align:start position:0% +becomes like an issue like here where + + + align:start position:0% +becomes like an issue like here where +there's so many participants in the + + align:start position:0% +there's so many participants in the + + + align:start position:0% +there's so many participants in the +process like third-party Healthcare + + align:start position:0% +process like third-party Healthcare + + + align:start position:0% +process like third-party Healthcare +managers + + align:start position:0% +managers + + + align:start position:0% +managers +it's a great question I I will say given + + align:start position:0% +it's a great question I I will say given + + + align:start position:0% +it's a great question I I will say given +the + + align:start position:0% +the + + + align:start position:0% +the +um threats that I just received from + + align:start position:0% +um threats that I just received from + + + align:start position:0% +um threats that I just received from +your divorce director that of all my + + align:start position:0% +your divorce director that of all my + + + align:start position:0% +your divorce director that of all my +co-workers who are working on this + + align:start position:0% +co-workers who are working on this + + + align:start position:0% +co-workers who are working on this +question are the ideal structure how + + align:start position:0% +question are the ideal structure how + + + align:start position:0% +question are the ideal structure how +many health workers + + align:start position:0% +many health workers + + + align:start position:0% +many health workers +um to nurses to doctors how do they fit + + align:start position:0% +um to nurses to doctors how do they fit + + + align:start position:0% +um to nurses to doctors how do they fit +in with a larger community of people + + align:start position:0% +in with a larger community of people + + + align:start position:0% +in with a larger community of people +living in HIV women's groups Community + + align:start position:0% +living in HIV women's groups Community + + + align:start position:0% +living in HIV women's groups Community +groups how they fit in with the ministry + + align:start position:0% +groups how they fit in with the ministry + + + align:start position:0% +groups how they fit in with the ministry +it's actually there's quite a number of + + align:start position:0% +it's actually there's quite a number of + + + align:start position:0% +it's actually there's quite a number of +us in Rwanda working on this project and + + align:start position:0% +us in Rwanda working on this project and + + + align:start position:0% +us in Rwanda working on this project and +Michael Rich my wife plenty of people + + align:start position:0% +Michael Rich my wife plenty of people + + + align:start position:0% +Michael Rich my wife plenty of people +were working really on this question + + align:start position:0% +were working really on this question + + + align:start position:0% +were working really on this question +what's this what should it look like + + align:start position:0% +what's this what should it look like + + + align:start position:0% +what's this what should it look like +I think that that's going to lead to a + + align:start position:0% +I think that that's going to lead to a + + + align:start position:0% +I think that that's going to lead to a +great efflorescence of you know + + align:start position:0% +great efflorescence of you know + + + align:start position:0% +great efflorescence of you know +knowledge and and its review and + + align:start position:0% +knowledge and and its review and + + + align:start position:0% +knowledge and and its review and +publication but I can connect you to all + + align:start position:0% +publication but I can connect you to all + + + align:start position:0% +publication but I can connect you to all +that right now and they've already + + align:start position:0% +that right now and they've already + + + align:start position:0% +that right now and they've already +started I think to publish them stuff + + align:start position:0% +started I think to publish them stuff + + + align:start position:0% +started I think to publish them stuff +from the door stoop Grant I don't know + + align:start position:0% +from the door stoop Grant I don't know + + + align:start position:0% +from the door stoop Grant I don't know +if that's true + + align:start position:0% +if that's true + + + align:start position:0% +if that's true +um but as far as third party payers in + + align:start position:0% +um but as far as third party payers in + + + align:start position:0% +um but as far as third party payers in +the complexities that we've seen in + + align:start position:0% +the complexities that we've seen in + + + align:start position:0% +the complexities that we've seen in +resource non-poor settings non-resource + + align:start position:0% +resource non-poor settings non-resource + + + align:start position:0% +resource non-poor settings non-resource +course settings sorry we're starting to + + align:start position:0% +course settings sorry we're starting to + + + align:start position:0% +course settings sorry we're starting to +see that in Haiti too I mean that that + + align:start position:0% +see that in Haiti too I mean that that + + + align:start position:0% +see that in Haiti too I mean that that +challenge for example this new hospital + + align:start position:0% +challenge for example this new hospital + + + align:start position:0% +challenge for example this new hospital +we're building looking at Dr Pierre + + align:start position:0% +we're building looking at Dr Pierre + + + align:start position:0% +we're building looking at Dr Pierre +we're going to suddenly for the first + + align:start position:0% +we're going to suddenly for the first + + + align:start position:0% +we're going to suddenly for the first +time in our history the 200 000 insured + + align:start position:0% +time in our history the 200 000 insured + + + align:start position:0% +time in our history the 200 000 insured +families in Haiti out of the 11 million + + align:start position:0% +families in Haiti out of the 11 million + + + align:start position:0% +families in Haiti out of the 11 million +uninsured are going to be coming to us + + align:start position:0% +uninsured are going to be coming to us + + + align:start position:0% +uninsured are going to be coming to us +with actually the ability to reimburse + + align:start position:0% +with actually the ability to reimburse + + + align:start position:0% +with actually the ability to reimburse +us I mean it's going to be a novel + + align:start position:0% +us I mean it's going to be a novel + + + align:start position:0% +us I mean it's going to be a novel +experience let me tell you so we're also + + align:start position:0% +experience let me tell you so we're also + + + align:start position:0% +experience let me tell you so we're also +going to have to take on that kind of + + align:start position:0% +going to have to take on that kind of + + + align:start position:0% +going to have to take on that kind of +complexity to moving forward in Rwanda + + align:start position:0% +complexity to moving forward in Rwanda + + + align:start position:0% +complexity to moving forward in Rwanda +that was sort of pushed on us with a + + align:start position:0% +that was sort of pushed on us with a + + + align:start position:0% +that was sort of pushed on us with a +mutual system and insurance system there + + align:start position:0% +mutual system and insurance system there + + + align:start position:0% +mutual system and insurance system there +was also community-based but I think we + + align:start position:0% +was also community-based but I think we + + + align:start position:0% +was also community-based but I think we +have to we're going to have to get + + align:start position:0% +have to we're going to have to get + + + align:start position:0% +have to we're going to have to get +stronger at this in those settings with + + align:start position:0% +stronger at this in those settings with + + + align:start position:0% +stronger at this in those settings with +there aren't many formal structures like + + align:start position:0% +there aren't many formal structures like + + + align:start position:0% +there aren't many formal structures like +that and then see if you can apply + + align:start position:0% +that and then see if you can apply + + + align:start position:0% +that and then see if you can apply +lessons here or from here and going + + align:start position:0% +lessons here or from here and going + + + align:start position:0% +lessons here or from here and going +forward well anyway thank you all very + + align:start position:0% +forward well anyway thank you all very + + + align:start position:0% +forward well anyway thank you all very +much and I'll Stick Around + + align:start position:0% + + + + align:start position:0% + +okay thanks \ No newline at end of file diff --git a/OT04cEdpK-M.txt b/OT04cEdpK-M.txt new file mode 100644 index 0000000000000000000000000000000000000000..1e107d107c2a1e5d5669f267f29a6312c3fcaf1b --- /dev/null +++ b/OT04cEdpK-M.txt @@ -0,0 +1,8519 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit MIT opencourseware + + align:start position:0% +of MIT courses visit MIT opencourseware + + + align:start position:0% +of MIT courses visit MIT opencourseware +at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu + + align:start position:0% +ocw.mit.edu + + + align:start position:0% +ocw.mit.edu +hello welcome to the first lecture in + + align:start position:0% +hello welcome to the first lecture in + + + align:start position:0% +hello welcome to the first lecture in +the last topic of this class so we we'll + + align:start position:0% +the last topic of this class so we we'll + + + align:start position:0% +the last topic of this class so we we'll +spend this lecture and the next lecture + + align:start position:0% +spend this lecture and the next lecture + + + align:start position:0% +spend this lecture and the next lecture +talking about + + align:start position:0% +talking about + + + align:start position:0% +talking about +modulation modulation like sampling is + + align:start position:0% +modulation modulation like sampling is + + + align:start position:0% +modulation modulation like sampling is +an excellent illustration of the power + + align:start position:0% +an excellent illustration of the power + + + align:start position:0% +an excellent illustration of the power +of thinking about signals in terms of + + align:start position:0% +of thinking about signals in terms of + + + align:start position:0% +of thinking about signals in terms of +their 4A transforms we'll see just like + + align:start position:0% +their 4A transforms we'll see just like + + + align:start position:0% +their 4A transforms we'll see just like +we saw in sampling that a problem that + + align:start position:0% +we saw in sampling that a problem that + + + align:start position:0% +we saw in sampling that a problem that +was potentially very complicated to + + align:start position:0% +was potentially very complicated to + + + align:start position:0% +was potentially very complicated to +understand sampling was very easy when + + align:start position:0% +understand sampling was very easy when + + + align:start position:0% +understand sampling was very easy when +you thought about it in the 48 domain + + align:start position:0% +you thought about it in the 48 domain + + + align:start position:0% +you thought about it in the 48 domain +and precisely the same thing happens + + align:start position:0% +and precisely the same thing happens + + + align:start position:0% +and precisely the same thing happens +with modulation which is precisely the + + align:start position:0% +with modulation which is precisely the + + + align:start position:0% +with modulation which is precisely the +reason we're talking about it now + + align:start position:0% +reason we're talking about it now + + + align:start position:0% +reason we're talking about it now +so I'll talk about modulation in the + + align:start position:0% +so I'll talk about modulation in the + + + align:start position:0% +so I'll talk about modulation in the +context of a communication + + align:start position:0% +context of a communication + + + align:start position:0% +context of a communication +system that's just for convenience in + + align:start position:0% +system that's just for convenience in + + + align:start position:0% +system that's just for convenience in +fact modulation is used in lots of other + + align:start position:0% +fact modulation is used in lots of other + + + align:start position:0% +fact modulation is used in lots of other +places in fact next time in the next + + align:start position:0% +places in fact next time in the next + + + align:start position:0% +places in fact next time in the next +lecture I'll show you an application of + + align:start position:0% +lecture I'll show you an application of + + + align:start position:0% +lecture I'll show you an application of +modulation from my research group where + + align:start position:0% +modulation from my research group where + + + align:start position:0% +modulation from my research group where +we use modulation to improve the + + align:start position:0% +we use modulation to improve the + + + align:start position:0% +we use modulation to improve the +resolution of an optical + + align:start position:0% +resolution of an optical + + + align:start position:0% +resolution of an optical +microscope nothing whatever to do with + + align:start position:0% +microscope nothing whatever to do with + + + align:start position:0% +microscope nothing whatever to do with +Communications but it's still the + + align:start position:0% +Communications but it's still the + + + align:start position:0% +Communications but it's still the +optical microscope the enhancement to + + align:start position:0% +optical microscope the enhancement to + + + align:start position:0% +optical microscope the enhancement to +resolution that we U achieve is directly + + align:start position:0% +resolution that we U achieve is directly + + + align:start position:0% +resolution that we U achieve is directly +based on the principles that I start to + + align:start position:0% +based on the principles that I start to + + + align:start position:0% +based on the principles that I start to +describe + + align:start position:0% +describe + + + align:start position:0% +describe +today so I'll talk about uh modulation + + align:start position:0% +today so I'll talk about uh modulation + + + align:start position:0% +today so I'll talk about uh modulation +today in the context of communications + + align:start position:0% +today in the context of communications + + + align:start position:0% +today in the context of communications +probably the most convenient easiest to + + align:start position:0% +probably the most convenient easiest to + + + align:start position:0% +probably the most convenient easiest to +think about communication system to all + + align:start position:0% +think about communication system to all + + + align:start position:0% +think about communication system to all +of us being humans is speech okay that + + align:start position:0% +of us being humans is speech okay that + + + align:start position:0% +of us being humans is speech okay that +we use speech for communication all the + + align:start position:0% +we use speech for communication all the + + + align:start position:0% +we use speech for communication all the +time it's very easy to think about how + + align:start position:0% +time it's very easy to think about how + + + align:start position:0% +time it's very easy to think about how +communication works as a how speech + + align:start position:0% +communication works as a how speech + + + align:start position:0% +communication works as a how speech +works as a communication medium somebody + + align:start position:0% +works as a communication medium somebody + + + align:start position:0% +works as a communication medium somebody +talks somebody listen + + align:start position:0% +talks somebody listen + + + align:start position:0% +talks somebody listen +one of the first ways of thinking about + + align:start position:0% +one of the first ways of thinking about + + + align:start position:0% +one of the first ways of thinking about +it as a um technological uh feat was the + + align:start position:0% +it as a um technological uh feat was the + + + align:start position:0% +it as a um technological uh feat was the +telephone the idea being that you + + align:start position:0% +telephone the idea being that you + + + align:start position:0% +telephone the idea being that you +convert the sound that I'm emitting when + + align:start position:0% +convert the sound that I'm emitting when + + + align:start position:0% +convert the sound that I'm emitting when +I'm speaking by a microphone into an + + align:start position:0% +I'm speaking by a microphone into an + + + align:start position:0% +I'm speaking by a microphone into an +electrical representation that gets shot + + align:start position:0% +electrical representation that gets shot + + + align:start position:0% +electrical representation that gets shot +down a + + align:start position:0% +down a + + + align:start position:0% +down a +wire then at the other end you take the + + align:start position:0% +wire then at the other end you take the + + + align:start position:0% +wire then at the other end you take the +electrical P the electrical signal + + align:start position:0% +electrical P the electrical signal + + + align:start position:0% +electrical P the electrical signal +that's coming down the wire and turn it + + align:start position:0% +that's coming down the wire and turn it + + + align:start position:0% +that's coming down the wire and turn it +back into a sound that's the principle + + align:start position:0% +back into a sound that's the principle + + + align:start position:0% +back into a sound that's the principle +of um of a telephone works very well + + align:start position:0% +of um of a telephone works very well + + + align:start position:0% +of um of a telephone works very well +modulation comes up when we start to + + align:start position:0% +modulation comes up when we start to + + + align:start position:0% +modulation comes up when we start to +think about how would we um generalize + + align:start position:0% +think about how would we um generalize + + + align:start position:0% +think about how would we um generalize +this notion for wireless communication + + align:start position:0% +this notion for wireless communication + + + align:start position:0% +this notion for wireless communication +in particular if we do cell phone + + align:start position:0% +in particular if we do cell phone + + + align:start position:0% +in particular if we do cell phone +communication cell phones + + align:start position:0% +communication cell phones + + + align:start position:0% +communication cell phones +transmit the signal that is picked up + + align:start position:0% +transmit the signal that is picked up + + + align:start position:0% +transmit the signal that is picked up +from the + + align:start position:0% +from the + + + align:start position:0% +from the +microphone that signal gets converted + + align:start position:0% +microphone that signal gets converted + + + align:start position:0% +microphone that signal gets converted +into electromagnetic signals That's the + + align:start position:0% +into electromagnetic signals That's the + + + align:start position:0% +into electromagnetic signals That's the +basis by which cell phones communicate + + align:start position:0% +basis by which cell phones communicate + + + align:start position:0% +basis by which cell phones communicate +with the cell tower the towers May + + align:start position:0% +with the cell tower the towers May + + + align:start position:0% +with the cell tower the towers May +communicate with other Towers via a lot + + align:start position:0% +communicate with other Towers via a lot + + + align:start position:0% +communicate with other Towers via a lot +of different kinds of Technologies I'm + + align:start position:0% +of different kinds of Technologies I'm + + + align:start position:0% +of different kinds of Technologies I'm +ignoring those for now but the + + align:start position:0% +ignoring those for now but the + + + align:start position:0% +ignoring those for now but the +communication between the phone and the + + align:start position:0% +communication between the phone and the + + + align:start position:0% +communication between the phone and the +tower is via electromagnetic + + align:start position:0% +tower is via electromagnetic + + + align:start position:0% +tower is via electromagnetic +waves and there's an interesting thing + + align:start position:0% +waves and there's an interesting thing + + + align:start position:0% +waves and there's an interesting thing +that happens when you try to recode the + + align:start position:0% +that happens when you try to recode the + + + align:start position:0% +that happens when you try to recode the +signal that would have been perfectly + + align:start position:0% +signal that would have been perfectly + + + align:start position:0% +signal that would have been perfectly +happy running down the copper wire when + + align:start position:0% +happy running down the copper wire when + + + align:start position:0% +happy running down the copper wire when +you try to recode that signal into an + + align:start position:0% +you try to recode that signal into an + + + align:start position:0% +you try to recode that signal into an +electromagnetic wave and that has to do + + align:start position:0% +electromagnetic wave and that has to do + + + align:start position:0% +electromagnetic wave and that has to do +with basic physics of electromagnetics + + align:start position:0% +with basic physics of electromagnetics + + + align:start position:0% +with basic physics of electromagnetics +waves which I'm sure you all know and so + + align:start position:0% +waves which I'm sure you all know and so + + + align:start position:0% +waves which I'm sure you all know and so +uh I'll just remind you of one simple + + align:start position:0% +uh I'll just remind you of one simple + + + align:start position:0% +uh I'll just remind you of one simple +idea so for efficient transmission from + + align:start position:0% +idea so for efficient transmission from + + + align:start position:0% +idea so for efficient transmission from +an electrical representation to an + + align:start position:0% +an electrical representation to an + + + align:start position:0% +an electrical representation to an +electromagnetic + + align:start position:0% +electromagnetic + + + align:start position:0% +electromagnetic +wave first off that that U transduction + + align:start position:0% +wave first off that that U transduction + + + align:start position:0% +wave first off that that U transduction +is mediated by something we call an + + align:start position:0% +is mediated by something we call an + + + align:start position:0% +is mediated by something we call an +antenna antennas will take an electrical + + align:start position:0% +antenna antennas will take an electrical + + + align:start position:0% +antenna antennas will take an electrical +signal and convert it into an + + align:start position:0% +signal and convert it into an + + + align:start position:0% +signal and convert it into an +electromagnetic wave and vice + + align:start position:0% +electromagnetic wave and vice + + + align:start position:0% +electromagnetic wave and vice +versa but the efficiency with which an + + align:start position:0% +versa but the efficiency with which an + + + align:start position:0% +versa but the efficiency with which an +antenna + + align:start position:0% +antenna + + + align:start position:0% +antenna +works has to do uh among other things + + align:start position:0% +works has to do uh among other things + + + align:start position:0% +works has to do uh among other things +with its + + align:start position:0% +with its + + + align:start position:0% +with its +size it's very difficult by which I mean + + align:start position:0% +size it's very difficult by which I mean + + + align:start position:0% +size it's very difficult by which I mean +it takes lots of + + align:start position:0% +it takes lots of + + + align:start position:0% +it takes lots of +power to transmit a signal to transform + + align:start position:0% +power to transmit a signal to transform + + + align:start position:0% +power to transmit a signal to transform +a signal from an electrical + + align:start position:0% +a signal from an electrical + + + align:start position:0% +a signal from an electrical +representation to an enm representation + + align:start position:0% +representation to an enm representation + + + align:start position:0% +representation to an enm representation +if the antenna is smaller is + + align:start position:0% +if the antenna is smaller is + + + align:start position:0% +if the antenna is smaller is +significantly smaller than the + + align:start position:0% +significantly smaller than the + + + align:start position:0% +significantly smaller than the +wavelength of + + align:start position:0% +wavelength of + + + align:start position:0% +wavelength of +Interest okay so um it's not that you + + align:start position:0% +Interest okay so um it's not that you + + + align:start position:0% +Interest okay so um it's not that you +can't do it is that it takes lots of + + align:start position:0% +can't do it is that it takes lots of + + + align:start position:0% +can't do it is that it takes lots of +power so if you don't want to burn a lot + + align:start position:0% +power so if you don't want to burn a lot + + + align:start position:0% +power so if you don't want to burn a lot +of power do doing that transformation + + align:start position:0% +of power do doing that transformation + + + align:start position:0% +of power do doing that transformation +then you need to make an antenna that's + + align:start position:0% +then you need to make an antenna that's + + + align:start position:0% +then you need to make an antenna that's +roughly the size of the wavelength that + + align:start position:0% +roughly the size of the wavelength that + + + align:start position:0% +roughly the size of the wavelength that +you're trying to to uh transmit as an + + align:start position:0% +you're trying to to uh transmit as an + + + align:start position:0% +you're trying to to uh transmit as an +electromagnetic wave okay so if we were + + align:start position:0% +electromagnetic wave okay so if we were + + + align:start position:0% +electromagnetic wave okay so if we were +thinking about this kind of a scheme for + + align:start position:0% +thinking about this kind of a scheme for + + + align:start position:0% +thinking about this kind of a scheme for +the communication of voice we've talked + + align:start position:0% +the communication of voice we've talked + + + align:start position:0% +the communication of voice we've talked +about voice many times telephone quality + + align:start position:0% +about voice many times telephone quality + + + align:start position:0% +about voice many times telephone quality +voice is usually defined to be + + align:start position:0% +voice is usually defined to be + + + align:start position:0% +voice is usually defined to be +frequencies between about 200 htz and + + align:start position:0% +frequencies between about 200 htz and + + + align:start position:0% +frequencies between about 200 htz and +about 3 khz if I had a signal that was + + align:start position:0% +about 3 khz if I had a signal that was + + + align:start position:0% +about 3 khz if I had a signal that was +composed of those kinds of frequencies + + align:start position:0% +composed of those kinds of frequencies + + + align:start position:0% +composed of those kinds of frequencies +how big should I make the + + align:start position:0% +how big should I make the + + + align:start position:0% +how big should I make the +antenna to get efficient coupling + + align:start position:0% +antenna to get efficient coupling + + + align:start position:0% +antenna to get efficient coupling +between the electrical representation in + + align:start position:0% +between the electrical representation in + + + align:start position:0% +between the electrical representation in +the cell phone and the electromagnetic + + align:start position:0% +the cell phone and the electromagnetic + + + align:start position:0% +the cell phone and the electromagnetic +wave that the cell phone wants to launch + + align:start position:0% +wave that the cell phone wants to launch + + + align:start position:0% +wave that the cell phone wants to launch +to get to the cell tower so look at your + + align:start position:0% + + + + align:start position:0% + +neighbor okay that involves turning your + + align:start position:0% +neighbor okay that involves turning your + + + align:start position:0% +neighbor okay that involves turning your +head say hello and figure out how long + + align:start position:0% +head say hello and figure out how long + + + align:start position:0% +head say hello and figure out how long +should the antenna be + + align:start position:0% + + + + align:start position:0% + + + align:start position:0% + + + + align:start position:0% + +that's + + align:start position:0% + + + + align:start position:0% + +okay does everybody have an answer + + align:start position:0% +okay does everybody have an answer + + + align:start position:0% +okay does everybody have an answer +raise your hand if you don't have an + + align:start position:0% +raise your hand if you don't have an + + + align:start position:0% +raise your hand if you don't have an +answer H how do you like that for a + + align:start position:0% +answer H how do you like that for a + + + align:start position:0% +answer H how do you like that for a +switch of a raise your hand if you don't + + align:start position:0% +switch of a raise your hand if you don't + + + align:start position:0% +switch of a raise your hand if you don't +have an answer ah you all have answers + + align:start position:0% +have an answer ah you all have answers + + + align:start position:0% +have an answer ah you all have answers +okay so what's how big should the Anna + + align:start position:0% +okay so what's how big should the Anna + + + align:start position:0% +okay so what's how big should the Anna +be antenna be one two three four or + + align:start position:0% + + + + align:start position:0% + +five + + align:start position:0% +five + + + align:start position:0% +five +answer okay very good so the answer is + + align:start position:0% +answer okay very good so the answer is + + + align:start position:0% +answer okay very good so the answer is +really big right so uh you think about + + align:start position:0% +really big right so uh you think about + + + align:start position:0% +really big right so uh you think about +um the relationship between + + align:start position:0% +um the relationship between + + + align:start position:0% +um the relationship between +wavelength and distance so you can think + + align:start position:0% +wavelength and distance so you can think + + + align:start position:0% +wavelength and distance so you can think +about + + align:start position:0% +about + + + align:start position:0% +about +um the relationship is given by speed + + align:start position:0% +um the relationship is given by speed + + + align:start position:0% +um the relationship is given by speed +the speed of a wave is the wavelength + + align:start position:0% +the speed of a wave is the wavelength + + + align:start position:0% +the speed of a wave is the wavelength +how long it goes per + + align:start position:0% +how long it goes per + + + align:start position:0% +how long it goes per +cycle times the number of cycles per + + align:start position:0% +cycle times the number of cycles per + + + align:start position:0% +cycle times the number of cycles per +second F so that LE so you can solve + + align:start position:0% +second F so that LE so you can solve + + + align:start position:0% +second F so that LE so you can solve +that expression to find out the + + align:start position:0% +that expression to find out the + + + align:start position:0% +that expression to find out the +wavelength in terms of the speed which + + align:start position:0% +wavelength in terms of the speed which + + + align:start position:0% +wavelength in terms of the speed which +for an electromagnetic wave is the speed + + align:start position:0% +for an electromagnetic wave is the speed + + + align:start position:0% +for an electromagnetic wave is the speed +of of light uh 3 * 10 e + + align:start position:0% +of of light uh 3 * 10 e + + + align:start position:0% +of of light uh 3 * 10 e +m/s the hardest one to launch is the + + align:start position:0% +m/s the hardest one to launch is the + + + align:start position:0% +m/s the hardest one to launch is the +lowest + + align:start position:0% +lowest + + + align:start position:0% +lowest +frequency right that will take the + + align:start position:0% +frequency right that will take the + + + align:start position:0% +frequency right that will take the +biggest antenna so the lowest frequency + + align:start position:0% +biggest antenna so the lowest frequency + + + align:start position:0% +biggest antenna so the lowest frequency +in teleph in um in telephone quality + + align:start position:0% +in teleph in um in telephone quality + + + align:start position:0% +in teleph in um in telephone quality +speech is 200 Hertz so we get about uh + + align:start position:0% +speech is 200 Hertz so we get about uh + + + align:start position:0% +speech is 200 Hertz so we get about uh +1,500 + + align:start position:0% +1,500 + + + align:start position:0% +1,500 +kilometers okay kind of big okay kind of + + align:start position:0% +kilometers okay kind of big okay kind of + + + align:start position:0% +kilometers okay kind of big okay kind of +useless right if you were thinking about + + align:start position:0% +useless right if you were thinking about + + + align:start position:0% +useless right if you were thinking about +trying to make cellular communication + + align:start position:0% +trying to make cellular communication + + + align:start position:0% +trying to make cellular communication +and your antenna actually had to + + align:start position:0% +and your antenna actually had to + + + align:start position:0% +and your antenna actually had to +be500 kilometers right that just isn't + + align:start position:0% +be500 kilometers right that just isn't + + + align:start position:0% +be500 kilometers right that just isn't +going to work right okay so what do we + + align:start position:0% +going to work right okay so what do we + + + align:start position:0% +going to work right okay so what do we +do we obviously don't do this right + + align:start position:0% +do we obviously don't do this right + + + align:start position:0% +do we obviously don't do this right +uh so the answer is that you would need + + align:start position:0% +uh so the answer is that you would need + + + align:start position:0% +uh so the answer is that you would need +an antenna hundreds of miles in + + align:start position:0% +an antenna hundreds of miles in + + + align:start position:0% +an antenna hundreds of miles in +length so what frequency should you be + + align:start position:0% +length so what frequency should you be + + + align:start position:0% +length so what frequency should you be +using if you wanted to build a phone + + align:start position:0% +using if you wanted to build a phone + + + align:start position:0% +using if you wanted to build a phone +that kind of fit in your hand kind of 10 + + align:start position:0% +that kind of fit in your hand kind of 10 + + + align:start position:0% +that kind of fit in your hand kind of 10 +centimeters or + + align:start position:0% +centimeters or + + + align:start position:0% +centimeters or +so what would be the frequency what in + + align:start position:0% +so what would be the frequency what in + + + align:start position:0% +so what would be the frequency what in +what would be the interesting range of + + align:start position:0% +what would be the interesting range of + + + align:start position:0% +what would be the interesting range of +frequencies that you would want to use + + align:start position:0% +frequencies that you would want to use + + + align:start position:0% +frequencies that you would want to use +for such a device + + align:start position:0% + + + + align:start position:0% + +and the answer + + align:start position:0% +and the answer + + + align:start position:0% +and the answer +is of course so the answer is you go to + + align:start position:0% +is of course so the answer is you go to + + + align:start position:0% +is of course so the answer is you go to +the bottom one it's bigger than a + + align:start position:0% +the bottom one it's bigger than a + + + align:start position:0% +the bottom one it's bigger than a +gigahertz and it's just running the the + + align:start position:0% +gigahertz and it's just running the the + + + align:start position:0% +gigahertz and it's just running the the +same expression in the other direction + + align:start position:0% +same expression in the other direction + + + align:start position:0% +same expression in the other direction +so you think about um uh the frequency + + align:start position:0% +so you think about um uh the frequency + + + align:start position:0% +so you think about um uh the frequency +that you would like would be the speed + + align:start position:0% +that you would like would be the speed + + + align:start position:0% +that you would like would be the speed +of light divided by the wavelength if + + align:start position:0% +of light divided by the wavelength if + + + align:start position:0% +of light divided by the wavelength if +you wanted the wavelength to be 10 cm + + align:start position:0% +you wanted the wavelength to be 10 cm + + + align:start position:0% +you wanted the wavelength to be 10 cm +then you would end up with a a frequency + + align:start position:0% +then you would end up with a a frequency + + + align:start position:0% +then you would end up with a a frequency +on the order of gigahertz and it + + align:start position:0% +on the order of gigahertz and it + + + align:start position:0% +on the order of gigahertz and it +shouldn't come as a surprise to you then + + align:start position:0% +shouldn't come as a surprise to you then + + + align:start position:0% +shouldn't come as a surprise to you then +that that's what we use in C + + align:start position:0% +that that's what we use in C + + + align:start position:0% +that that's what we use in C +Communications so a modern cell phone + + align:start position:0% +Communications so a modern cell phone + + + align:start position:0% +Communications so a modern cell phone +uses 2.1 uh Mega uh + + align:start position:0% +uses 2.1 uh Mega uh + + + align:start position:0% +uses 2.1 uh Mega uh +gahz so uh the point is that what when + + align:start position:0% +gahz so uh the point is that what when + + + align:start position:0% +gahz so uh the point is that what when +we're thinking + + align:start position:0% +we're thinking + + + align:start position:0% +we're thinking +about uh how we would like to use the + + align:start position:0% +about uh how we would like to use the + + + align:start position:0% +about uh how we would like to use the +electromagnetic spectrum for + + align:start position:0% +electromagnetic spectrum for + + + align:start position:0% +electromagnetic spectrum for +communications tasks that spectrum is + + align:start position:0% +communications tasks that spectrum is + + + align:start position:0% +communications tasks that spectrum is +not necessarily well matched to the + + align:start position:0% +not necessarily well matched to the + + + align:start position:0% +not necessarily well matched to the +communications problem of interest you + + align:start position:0% +communications problem of interest you + + + align:start position:0% +communications problem of interest you +might think that that cellular example + + align:start position:0% +might think that that cellular example + + + align:start position:0% +might think that that cellular example +is an exception in fact that's the rule + + align:start position:0% +is an exception in fact that's the rule + + + align:start position:0% +is an exception in fact that's the rule +if you try to have a signal of Interest + + align:start position:0% +if you try to have a signal of Interest + + + align:start position:0% +if you try to have a signal of Interest +transmitted over a medium or stored on + + align:start position:0% +transmitted over a medium or stored on + + + align:start position:0% +transmitted over a medium or stored on +some sort of a medium it is generally + + align:start position:0% +some sort of a medium it is generally + + + align:start position:0% +some sort of a medium it is generally +the case that there's a matching problem + + align:start position:0% +the case that there's a matching problem + + + align:start position:0% +the case that there's a matching problem +that the characteristics of the medium + + align:start position:0% +that the characteristics of the medium + + + align:start position:0% +that the characteristics of the medium +don't match the characteristics of the + + align:start position:0% +don't match the characteristics of the + + + align:start position:0% +don't match the characteristics of the +message and so uh part of communications + + align:start position:0% +message and so uh part of communications + + + align:start position:0% +message and so uh part of communications +engineering is trying to come up with a + + align:start position:0% +engineering is trying to come up with a + + + align:start position:0% +engineering is trying to come up with a +coding + + align:start position:0% +coding + + + align:start position:0% +coding +scheme that matches the mess the + + align:start position:0% +scheme that matches the mess the + + + align:start position:0% +scheme that matches the mess the +characteristics of the message to the + + align:start position:0% +characteristics of the message to the + + + align:start position:0% +characteristics of the message to the +characteristics of the + + align:start position:0% +characteristics of the + + + align:start position:0% +characteristics of the +medium um and so what I'm going to do + + align:start position:0% +medium um and so what I'm going to do + + + align:start position:0% +medium um and so what I'm going to do +today is talk about uh some matching + + align:start position:0% +today is talk about uh some matching + + + align:start position:0% +today is talk about uh some matching +schemes based on + + align:start position:0% +schemes based on + + + align:start position:0% +schemes based on +modulation so we just saw that if we + + align:start position:0% +modulation so we just saw that if we + + + align:start position:0% +modulation so we just saw that if we +wanted to do cellular communication of + + align:start position:0% +wanted to do cellular communication of + + + align:start position:0% +wanted to do cellular communication of +voice voice might have a spectrum + + align:start position:0% +voice voice might have a spectrum + + + align:start position:0% +voice voice might have a spectrum +represented by by uh this magnitude + + align:start position:0% +represented by by uh this magnitude + + + align:start position:0% +represented by by uh this magnitude +function X where the bandwidth is on the + + align:start position:0% +function X where the bandwidth is on the + + + align:start position:0% +function X where the bandwidth is on the +order of a few + + align:start position:0% + + + + align:start position:0% + +kilohertz but we might want to transmit + + align:start position:0% +kilohertz but we might want to transmit + + + align:start position:0% +kilohertz but we might want to transmit +a signal that has the same information + + align:start position:0% +a signal that has the same information + + + align:start position:0% +a signal that has the same information +however we would like the frequencies to + + align:start position:0% +however we would like the frequencies to + + + align:start position:0% +however we would like the frequencies to +be up around 2 + + align:start position:0% + + + + align:start position:0% + +gigahertz which of these coding schemes + + align:start position:0% +gigahertz which of these coding schemes + + + align:start position:0% +gigahertz which of these coding schemes +y as a function of + + align:start position:0% +y as a function of + + + align:start position:0% +y as a function of +X achieves this transformation take the + + align:start position:0% +X achieves this transformation take the + + + align:start position:0% +X achieves this transformation take the +stuff that you have at a low frequency + + align:start position:0% +stuff that you have at a low frequency + + + align:start position:0% +stuff that you have at a low frequency +in a low frequency range and shift it to + + align:start position:0% +in a low frequency range and shift it to + + + align:start position:0% +in a low frequency range and shift it to +a high frequency range what would you + + align:start position:0% + + + + align:start position:0% + +do the obvious answer is to stare blind + + align:start position:0% +do the obvious answer is to stare blind + + + align:start position:0% +do the obvious answer is to stare blind +with a blank face toward and it it'll + + align:start position:0% +with a blank face toward and it it'll + + + align:start position:0% +with a blank face toward and it it'll +definitely come to you + + align:start position:0% +definitely come to you + + + align:start position:0% +definitely come to you +right you don't want to talk to somebody + + align:start position:0% +right you don't want to talk to somebody + + + align:start position:0% +right you don't want to talk to somebody +else right that would give it away + + align:start position:0% + + + + align:start position:0% + +so what's the relationship between X of + + align:start position:0% +so what's the relationship between X of + + + align:start position:0% +so what's the relationship between X of +T and Y of t uh is it relation 1 2 3 4 + + align:start position:0% +T and Y of t uh is it relation 1 2 3 4 + + + align:start position:0% +T and Y of t uh is it relation 1 2 3 4 +or none of the + + align:start position:0% + + + + align:start position:0% + +above okay it's about 80% correct um so + + align:start position:0% +above okay it's about 80% correct um so + + + align:start position:0% +above okay it's about 80% correct um so +how do I think about it so if I have so + + align:start position:0% +how do I think about it so if I have so + + + align:start position:0% +how do I think about it so if I have so +let's see I've got I want to figure out + + align:start position:0% +let's see I've got I want to figure out + + + align:start position:0% +let's see I've got I want to figure out +a relationship between the 4A transform + + align:start position:0% +a relationship between the 4A transform + + + align:start position:0% +a relationship between the 4A transform +of Y and X okay so I want if I knew if I + + align:start position:0% +of Y and X okay so I want if I knew if I + + + align:start position:0% +of Y and X okay so I want if I knew if I +wanted to figure out the 4A transform of + + align:start position:0% +wanted to figure out the 4A transform of + + + align:start position:0% +wanted to figure out the 4A transform of +Y right so I would integrate y of + + align:start position:0% +Y right so I would integrate y of + + + align:start position:0% +Y right so I would integrate y of +T eus J Omega T DT right that looks kind + + align:start position:0% +T eus J Omega T DT right that looks kind + + + align:start position:0% +T eus J Omega T DT right that looks kind +of right and Y would be X of T let's say + + align:start position:0% +of right and Y would be X of T let's say + + + align:start position:0% +of right and Y would be X of T let's say +let's try the first one X of t e to the + + align:start position:0% +let's try the first one X of t e to the + + + align:start position:0% +let's try the first one X of t e to the +J Omega c t e minus J Omega T DT + + align:start position:0% + + + + align:start position:0% + +well that's almost the 48 transform of + + align:start position:0% +well that's almost the 48 transform of + + + align:start position:0% +well that's almost the 48 transform of +X right all I've done is shifted + + align:start position:0% +X right all I've done is shifted + + + align:start position:0% +X right all I've done is shifted +Omega so that's in fact that's the same + + align:start position:0% +Omega so that's in fact that's the same + + + align:start position:0% +Omega so that's in fact that's the same +as X of J Omega minus Omega C right and + + align:start position:0% +as X of J Omega minus Omega C right and + + + align:start position:0% +as X of J Omega minus Omega C right and +that's what I wanted to do right so the + + align:start position:0% +that's what I wanted to do right so the + + + align:start position:0% +that's what I wanted to do right so the +idea is that if you multiply by this + + align:start position:0% +idea is that if you multiply by this + + + align:start position:0% +idea is that if you multiply by this +complex exponential + + align:start position:0% +complex exponential + + + align:start position:0% +complex exponential +the effect of that multiplication in + + align:start position:0% +the effect of that multiplication in + + + align:start position:0% +the effect of that multiplication in +time is to shift + + align:start position:0% +time is to shift + + + align:start position:0% +time is to shift +frequencies can somebody say that to me + + align:start position:0% +frequencies can somebody say that to me + + + align:start position:0% +frequencies can somebody say that to me +say the same transformation but in + + align:start position:0% +say the same transformation but in + + + align:start position:0% +say the same transformation but in +slightly different + + align:start position:0% + + + + align:start position:0% + +words guess that was kind of + + align:start position:0% +words guess that was kind of + + + align:start position:0% +words guess that was kind of +big + + align:start position:0% + + + + align:start position:0% + +yes expon time multiply by exponential + + align:start position:0% +yes expon time multiply by exponential + + + align:start position:0% +yes expon time multiply by exponential +in time should correspond to + + align:start position:0% +in time should correspond to + + + align:start position:0% +in time should correspond to +so generally a multiplication in time + + align:start position:0% +so generally a multiplication in time + + + align:start position:0% +so generally a multiplication in time +corresponds + + align:start position:0% +corresponds + + + align:start position:0% +corresponds +to + + align:start position:0% +to + + + align:start position:0% +to +convolution so you could equivalently + + align:start position:0% +convolution so you could equivalently + + + align:start position:0% +convolution so you could equivalently +instead of saying it shifted in + + align:start position:0% +instead of saying it shifted in + + + align:start position:0% +instead of saying it shifted in +frequency you could + + align:start position:0% + + + + align:start position:0% + +say it got + + align:start position:0% +say it got + + + align:start position:0% +say it got +convolved with the Delta + + align:start position:0% +convolved with the Delta + + + align:start position:0% +convolved with the Delta +function so a different way of saying + + align:start position:0% +function so a different way of saying + + + align:start position:0% +function so a different way of saying +the same + + align:start position:0% +the same + + + align:start position:0% +the same +thing would be that you think about + + align:start position:0% +thing would be that you think about + + + align:start position:0% +thing would be that you think about +convolving with the Delta function in + + align:start position:0% +convolving with the Delta function in + + + align:start position:0% +convolving with the Delta function in +frequency okay same same thing okay now + + align:start position:0% +frequency okay same same thing okay now + + + align:start position:0% +frequency okay same same thing okay now +we don't actually do this right when + + align:start position:0% +we don't actually do this right when + + + align:start position:0% +we don't actually do this right when +we're doing the cell phone thing we + + align:start position:0% +we're doing the cell phone thing we + + + align:start position:0% +we're doing the cell phone thing we +don't actually multiply by e to the J + + align:start position:0% +don't actually multiply by e to the J + + + align:start position:0% +don't actually multiply by e to the J +Omega C anyone know + + align:start position:0% + + + + align:start position:0% + +why this is kind of the simplest way + + align:start position:0% +why this is kind of the simplest way + + + align:start position:0% +why this is kind of the simplest way +that you could imagine of taking + + align:start position:0% +that you could imagine of taking + + + align:start position:0% +that you could imagine of taking +frequency content centered near zero and + + align:start position:0% +frequency content centered near zero and + + + align:start position:0% +frequency content centered near zero and +turning it into frequency content + + align:start position:0% +turning it into frequency content + + + align:start position:0% +turning it into frequency content +centered near Omega C but that's not + + align:start position:0% +centered near Omega C but that's not + + + align:start position:0% +centered near Omega C but that's not +what we really do why don't we really do + + align:start position:0% +what we really do why don't we really do + + + align:start position:0% +what we really do why don't we really do +that exactly we don't really do it + + align:start position:0% +that exactly we don't really do it + + + align:start position:0% +that exactly we don't really do it +because the signal is not + + align:start position:0% +because the signal is not + + + align:start position:0% +because the signal is not +real right so how do you know the signal + + align:start position:0% +real right so how do you know the signal + + + align:start position:0% +real right so how do you know the signal +is not + + align:start position:0% + + + + align:start position:0% + +real so if the signal had been real the + + align:start position:0% +real so if the signal had been real the + + + align:start position:0% +real so if the signal had been real the +48 transform would have + + align:start position:0% + + + + align:start position:0% + +been if the signal had been real the 4A + + align:start position:0% +been if the signal had been real the 4A + + + align:start position:0% +been if the signal had been real the 4A +transform would have + + align:start position:0% +transform would have + + + align:start position:0% +transform would have +been X of J + + align:start position:0% + + + + align:start position:0% + +Omega if the signal had been real the 4A + + align:start position:0% +Omega if the signal had been real the 4A + + + align:start position:0% +Omega if the signal had been real the 4A +transform would have + + align:start position:0% + + + + align:start position:0% + +been some kind of symmetry right how do + + align:start position:0% +been some kind of symmetry right how do + + + align:start position:0% +been some kind of symmetry right how do +I see symmetry in that expression + + align:start position:0% +I see symmetry in that expression + + + align:start position:0% +I see symmetry in that expression +conjugate conjugate symmetry how do I + + align:start position:0% +conjugate conjugate symmetry how do I + + + align:start position:0% +conjugate conjugate symmetry how do I +see conjugate symmetry in that + + align:start position:0% + + + + align:start position:0% + +expression well I can you know this is + + align:start position:0% +expression well I can you know this is + + + align:start position:0% +expression well I can you know this is +post t plus J sin Omega + + align:start position:0% +post t plus J sin Omega + + + align:start position:0% +post t plus J sin Omega +T + + align:start position:0% + + + + align:start position:0% + +right so if this is a real signal then + + align:start position:0% +right so if this is a real signal then + + + align:start position:0% +right so if this is a real signal then +it gives rise to something here that is + + align:start position:0% +it gives rise to something here that is + + + align:start position:0% +it gives rise to something here that is +symmetric the cosine terms are all + + align:start position:0% +symmetric the cosine terms are all + + + align:start position:0% +symmetric the cosine terms are all +symmetric about the + + align:start position:0% +symmetric about the + + + align:start position:0% +symmetric about the +origin and it has an imaginary part that + + align:start position:0% +origin and it has an imaginary part that + + + align:start position:0% +origin and it has an imaginary part that +is antisymmetric about the origin right + + align:start position:0% +is antisymmetric about the origin right + + + align:start position:0% +is antisymmetric about the origin right +because you add together a bunch of + + align:start position:0% +because you add together a bunch of + + + align:start position:0% +because you add together a bunch of +cosin you can't get anything that's + + align:start position:0% +cosin you can't get anything that's + + + align:start position:0% +cosin you can't get anything that's +anything other than symmetric about the + + align:start position:0% +anything other than symmetric about the + + + align:start position:0% +anything other than symmetric about the +origin you add together a bunch of of + + align:start position:0% +origin you add together a bunch of of + + + align:start position:0% +origin you add together a bunch of of +signs you can't get anything except + + align:start position:0% +signs you can't get anything except + + + align:start position:0% +signs you can't get anything except +something that is anti- symmetric about + + align:start position:0% +something that is anti- symmetric about + + + align:start position:0% +something that is anti- symmetric about +the origin okay so you know this thing + + align:start position:0% +the origin okay so you know this thing + + + align:start position:0% +the origin okay so you know this thing +has to be um so a real signal would have + + align:start position:0% +has to be um so a real signal would have + + + align:start position:0% +has to be um so a real signal would have +had conjugate + + align:start position:0% +had conjugate + + + align:start position:0% +had conjugate +symmetry the real part would have been + + align:start position:0% +symmetry the real part would have been + + + align:start position:0% +symmetry the real part would have been +symmetric the imaginary part would be + + align:start position:0% +symmetric the imaginary part would be + + + align:start position:0% +symmetric the imaginary part would be +anti- symmetric and you can see that + + align:start position:0% +anti- symmetric and you can see that + + + align:start position:0% +anti- symmetric and you can see that +this is not conjugate symmetric right + + align:start position:0% +this is not conjugate symmetric right + + + align:start position:0% +this is not conjugate symmetric right +okay everybody knows what I'm talking + + align:start position:0% + + + + align:start position:0% + +about conjugate symmetry would mean that + + align:start position:0% +about conjugate symmetry would mean that + + + align:start position:0% +about conjugate symmetry would mean that +the real part of the signal is symmetric + + align:start position:0% +the real part of the signal is symmetric + + + align:start position:0% +the real part of the signal is symmetric +about the origin which means that if + + align:start position:0% +about the origin which means that if + + + align:start position:0% +about the origin which means that if +this is supposed to represent a real + + align:start position:0% +this is supposed to represent a real + + + align:start position:0% +this is supposed to represent a real +signal then there should have been a + + align:start position:0% +signal then there should have been a + + + align:start position:0% +signal then there should have been a +reflection over here to make it + + align:start position:0% +reflection over here to make it + + + align:start position:0% +reflection over here to make it +symmetric about the + + align:start position:0% + + + + align:start position:0% + +origin it was symmetric but I shifted it + + align:start position:0% +origin it was symmetric but I shifted it + + + align:start position:0% +origin it was symmetric but I shifted it +by a complex number I shifted it by Co + + align:start position:0% +by a complex number I shifted it by Co + + + align:start position:0% +by a complex number I shifted it by Co +Omega C plus J sin Omega C so I + + align:start position:0% +Omega C plus J sin Omega C so I + + + align:start position:0% +Omega C plus J sin Omega C so I +generated by that multiplication I + + align:start position:0% +generated by that multiplication I + + + align:start position:0% +generated by that multiplication I +generated a complex + + align:start position:0% + + + + align:start position:0% + +number so the signal so so uh this + + align:start position:0% +number so the signal so so uh this + + + align:start position:0% +number so the signal so so uh this +signal was complex valued and not + + align:start position:0% +signal was complex valued and not + + + align:start position:0% +signal was complex valued and not +conjugate + + align:start position:0% +conjugate + + + align:start position:0% +conjugate +symmetric okay so the point is trying to + + align:start position:0% +symmetric okay so the point is trying to + + + align:start position:0% +symmetric okay so the point is trying to +get you to remember the kinds of things + + align:start position:0% +get you to remember the kinds of things + + + align:start position:0% +get you to remember the kinds of things +that we're supposed to know about 48 + + align:start position:0% +that we're supposed to know about 48 + + + align:start position:0% +that we're supposed to know about 48 +transforms right so uh by shifting with + + align:start position:0% +transforms right so uh by shifting with + + + align:start position:0% +transforms right so uh by shifting with +a a um complex exponential we wreck the + + align:start position:0% +a a um complex exponential we wreck the + + + align:start position:0% +a a um complex exponential we wreck the +realness of the original signal the real + + align:start position:0% +realness of the original signal the real + + + align:start position:0% +realness of the original signal the real +re original signal would have been + + align:start position:0% +re original signal would have been + + + align:start position:0% +re original signal would have been +conjugate symmetric in + + align:start position:0% +conjugate symmetric in + + + align:start position:0% +conjugate symmetric in +frequency but the wrecking of it gave + + align:start position:0% +frequency but the wrecking of it gave + + + align:start position:0% +frequency but the wrecking of it gave +rise to a signal that was no longer + + align:start position:0% +rise to a signal that was no longer + + + align:start position:0% +rise to a signal that was no longer +conjugate symmetric in + + align:start position:0% +conjugate symmetric in + + + align:start position:0% +conjugate symmetric in +frequency okay so we don't really + + align:start position:0% +frequency okay so we don't really + + + align:start position:0% +frequency okay so we don't really +modulate this + + align:start position:0% +modulate this + + + align:start position:0% +modulate this +way but we do the obvious extension what + + align:start position:0% +way but we do the obvious extension what + + + align:start position:0% +way but we do the obvious extension what +we would uh do is modulate with a cosine + + align:start position:0% +we would uh do is modulate with a cosine + + + align:start position:0% +we would uh do is modulate with a cosine +wave okay so now if instead of + + align:start position:0% +wave okay so now if instead of + + + align:start position:0% +wave okay so now if instead of +multiplying by a complex exponential I + + align:start position:0% +multiplying by a complex exponential I + + + align:start position:0% +multiplying by a complex exponential I +multiply by the cosine Omega CT by oil's + + align:start position:0% +multiply by the cosine Omega CT by oil's + + + align:start position:0% +multiply by the cosine Omega CT by oil's +expression I can think about that as + + align:start position:0% +expression I can think about that as + + + align:start position:0% +expression I can think about that as +being uh the sum of two uh components + + align:start position:0% +being uh the sum of two uh components + + + align:start position:0% +being uh the sum of two uh components +one at plus Omega C and one at minus + + align:start position:0% +one at plus Omega C and one at minus + + + align:start position:0% +one at plus Omega C and one at minus +Omega C and now when I do the + + align:start position:0% +Omega C and now when I do the + + + align:start position:0% +Omega C and now when I do the +convolution I get a signal that is + + align:start position:0% +convolution I get a signal that is + + + align:start position:0% +convolution I get a signal that is +conjugate + + align:start position:0% +conjugate + + + align:start position:0% +conjugate +symmetric right so when I convolve this + + align:start position:0% +symmetric right so when I convolve this + + + align:start position:0% +symmetric right so when I convolve this +with this one this one gives me a copy + + align:start position:0% +with this one this one gives me a copy + + + align:start position:0% +with this one this one gives me a copy +of this here and when I convolve this + + align:start position:0% +of this here and when I convolve this + + + align:start position:0% +of this here and when I convolve this +with this one this one gives me a copy + + align:start position:0% +with this one this one gives me a copy + + + align:start position:0% +with this one this one gives me a copy +of this one down here so now the + + align:start position:0% +of this one down here so now the + + + align:start position:0% +of this one down here so now the +resulting signal + + align:start position:0% +resulting signal + + + align:start position:0% +resulting signal +which I know by construction if this was + + align:start position:0% +which I know by construction if this was + + + align:start position:0% +which I know by construction if this was +real and this was real then that's + + align:start position:0% +real and this was real then that's + + + align:start position:0% +real and this was real then that's +real right I know by construction that + + align:start position:0% +real right I know by construction that + + + align:start position:0% +real right I know by construction that +this signal must have been real but I + + align:start position:0% +this signal must have been real but I + + + align:start position:0% +this signal must have been real but I +can also see it in the transform because + + align:start position:0% +can also see it in the transform because + + + align:start position:0% +can also see it in the transform because +I can see now that there's a symmetry + + align:start position:0% +I can see now that there's a symmetry + + + align:start position:0% +I can see now that there's a symmetry +that is consistent with it being + + align:start position:0% +that is consistent with it being + + + align:start position:0% +that is consistent with it being +conjugate symmetric yes somebody had a + + align:start position:0% +conjugate symmetric yes somebody had a + + + align:start position:0% +conjugate symmetric yes somebody had a +question + + align:start position:0% +question + + + align:start position:0% +question +okay uh okay so that's what we mean by + + align:start position:0% +okay uh okay so that's what we mean by + + + align:start position:0% +okay uh okay so that's what we mean by +modulation this is modulation modulation + + align:start position:0% +modulation this is modulation modulation + + + align:start position:0% +modulation this is modulation modulation +just is a fancy word that means + + align:start position:0% +just is a fancy word that means + + + align:start position:0% +just is a fancy word that means +multiply so what we're going to do is is + + align:start position:0% +multiply so what we're going to do is is + + + align:start position:0% +multiply so what we're going to do is is +multiply the signal by a carrier the + + align:start position:0% +multiply the signal by a carrier the + + + align:start position:0% +multiply the signal by a carrier the +carrier is going to be a signal that + + align:start position:0% +carrier is going to be a signal that + + + align:start position:0% +carrier is going to be a signal that +carries the message through the medium + + align:start position:0% +carries the message through the medium + + + align:start position:0% +carries the message through the medium +okay the carrier is chosen so that it + + align:start position:0% +okay the carrier is chosen so that it + + + align:start position:0% +okay the carrier is chosen so that it +goes efficiently through the + + align:start position:0% +goes efficiently through the + + + align:start position:0% +goes efficiently through the +medium and then the carrier carries the + + align:start position:0% +medium and then the carrier carries the + + + align:start position:0% +medium and then the carrier carries the +message through the medium so we think + + align:start position:0% +message through the medium so we think + + + align:start position:0% +message through the medium so we think +about this as + + align:start position:0% +about this as + + + align:start position:0% +about this as +modulation and we want to be familiar + + align:start position:0% +modulation and we want to be familiar + + + align:start position:0% +modulation and we want to be familiar +with going back and forth between time + + align:start position:0% +with going back and forth between time + + + align:start position:0% +with going back and forth between time +and frequency you can also think about + + align:start position:0% +and frequency you can also think about + + + align:start position:0% +and frequency you can also think about +the result of modulation in time so if + + align:start position:0% +the result of modulation in time so if + + + align:start position:0% +the result of modulation in time so if +this were my message which is intended + + align:start position:0% +this were my message which is intended + + + align:start position:0% +this were my message which is intended +to be represented as a low + + align:start position:0% +to be represented as a low + + + align:start position:0% +to be represented as a low +frequency and this is my carrier which + + align:start position:0% +frequency and this is my carrier which + + + align:start position:0% +frequency and this is my carrier which +is intended to be represented as a + + align:start position:0% +is intended to be represented as a + + + align:start position:0% +is intended to be represented as a +higher frequency then when I modulate it + + align:start position:0% +higher frequency then when I modulate it + + + align:start position:0% +higher frequency then when I modulate it +I get a modulated signal by which I mean + + align:start position:0% +I get a modulated signal by which I mean + + + align:start position:0% +I get a modulated signal by which I mean +this is called amplitude + + align:start position:0% +this is called amplitude + + + align:start position:0% +this is called amplitude +modulation the amplitude of the carrier + + align:start position:0% +modulation the amplitude of the carrier + + + align:start position:0% +modulation the amplitude of the carrier +is modulated by the message that's all + + align:start position:0% +is modulated by the message that's all + + + align:start position:0% +is modulated by the message that's all +we + + align:start position:0% +we + + + align:start position:0% +we +mean so you can see that the transform + + align:start position:0% +mean so you can see that the transform + + + align:start position:0% +mean so you can see that the transform +this transformation which has the + + align:start position:0% +this transformation which has the + + + align:start position:0% +this transformation which has the +property of moving the information from + + align:start position:0% +property of moving the information from + + + align:start position:0% +property of moving the information from +a low frequency that's hard to transmit + + align:start position:0% +a low frequency that's hard to transmit + + + align:start position:0% +a low frequency that's hard to transmit +to a high frequency that is easy to + + align:start position:0% +to a high frequency that is easy to + + + align:start position:0% +to a high frequency that is easy to +transmit that has the effect of U uh + + align:start position:0% +transmit that has the effect of U uh + + + align:start position:0% +transmit that has the effect of U uh +doing a very particular dist uh U uh + + align:start position:0% +doing a very particular dist uh U uh + + + align:start position:0% +doing a very particular dist uh U uh +pattern to the time domain + + align:start position:0% +pattern to the time domain + + + align:start position:0% +pattern to the time domain +waveform okay now it would be completely + + align:start position:0% +waveform okay now it would be completely + + + align:start position:0% +waveform okay now it would be completely +useless as a communication scheme if it + + align:start position:0% +useless as a communication scheme if it + + + align:start position:0% +useless as a communication scheme if it +weren't easy to + + align:start position:0% + + + + align:start position:0% + +invert so imagine that I have this + + align:start position:0% +invert so imagine that I have this + + + align:start position:0% +invert so imagine that I have this +signal and what I'd like to do is + + align:start position:0% +signal and what I'd like to do is + + + align:start position:0% +signal and what I'd like to do is +recover X + + align:start position:0% +recover X + + + align:start position:0% +recover X +what should I do to recover X the + + align:start position:0% +what should I do to recover X the + + + align:start position:0% +what should I do to recover X the +original message so the idea is I have + + align:start position:0% +original message so the idea is I have + + + align:start position:0% +original message so the idea is I have +an original message in my available in + + align:start position:0% +an original message in my available in + + + align:start position:0% +an original message in my available in +my cell phone it gets modulated so that + + align:start position:0% +my cell phone it gets modulated so that + + + align:start position:0% +my cell phone it gets modulated so that +it can be launched into electromagnetic + + align:start position:0% +it can be launched into electromagnetic + + + align:start position:0% +it can be launched into electromagnetic +waves the electromagnetic waves go to a + + align:start position:0% +waves the electromagnetic waves go to a + + + align:start position:0% +waves the electromagnetic waves go to a +receiver uh thousands of miles away and + + align:start position:0% +receiver uh thousands of miles away and + + + align:start position:0% +receiver uh thousands of miles away and +now the idea is to reconstruct my + + align:start position:0% +now the idea is to reconstruct my + + + align:start position:0% +now the idea is to reconstruct my +original signal x what would I do what + + align:start position:0% +original signal x what would I do what + + + align:start position:0% +original signal x what would I do what +kind of a system would I use to recover + + align:start position:0% +kind of a system would I use to recover + + + align:start position:0% +kind of a system would I use to recover +X from y + + align:start position:0% + + + + align:start position:0% + +I'm sorry you need divide out the you + + align:start position:0% +I'm sorry you need divide out the you + + + align:start position:0% +I'm sorry you need divide out the you +could divide out the cosine so you could + + align:start position:0% +could divide out the cosine so you could + + + align:start position:0% +could divide out the cosine so you could +you could take uh X of T cosine Omega CT + + align:start position:0% +you could take uh X of T cosine Omega CT + + + align:start position:0% +you could take uh X of T cosine Omega CT +times something uh what do I want to say + + align:start position:0% +times something uh what do I want to say + + + align:start position:0% +times something uh what do I want to say +a of + + align:start position:0% +a of + + + align:start position:0% +a of +T designed so that this times this is + + align:start position:0% +T designed so that this times this is + + + align:start position:0% +T designed so that this times this is +one + + align:start position:0% +one + + + align:start position:0% +one +right that's kind of ugly anybody see + + align:start position:0% +right that's kind of ugly anybody see + + + align:start position:0% +right that's kind of ugly anybody see +anything ugly about that + + align:start position:0% +anything ugly about that + + + align:start position:0% +anything ugly about that +yeah shift it back the other way you + + align:start position:0% +yeah shift it back the other way you + + + align:start position:0% +yeah shift it back the other way you +could also shift it back the other way + + align:start position:0% +could also shift it back the other way + + + align:start position:0% +could also shift it back the other way +so before we do that why is this + + align:start position:0% +so before we do that why is this + + + align:start position:0% +so before we do that why is this +ugly the zeros right so if we wanted to + + align:start position:0% +ugly the zeros right so if we wanted to + + + align:start position:0% +ugly the zeros right so if we wanted to +take a signal that looks like a a cosine + + align:start position:0% +take a signal that looks like a a cosine + + + align:start position:0% +take a signal that looks like a a cosine +wave and multiply it by some signal that + + align:start position:0% +wave and multiply it by some signal that + + + align:start position:0% +wave and multiply it by some signal that +generates one right that's not too hard + + align:start position:0% +generates one right that's not too hard + + + align:start position:0% +generates one right that's not too hard +to do here right you would do that with + + align:start position:0% +to do here right you would do that with + + + align:start position:0% +to do here right you would do that with +something like this but it becomes very + + align:start position:0% +something like this but it becomes very + + + align:start position:0% +something like this but it becomes very +hard to do here so you would end up + + align:start position:0% +hard to do here so you would end up + + + align:start position:0% +hard to do here so you would end up +making some signal that does some + + align:start position:0% +making some signal that does some + + + align:start position:0% +making some signal that does some +awful right so it would periodically be + + align:start position:0% +awful right so it would periodically be + + + align:start position:0% +awful right so it would periodically be +a + + align:start position:0% +a + + + align:start position:0% +a +mess right but you can do what you said + + align:start position:0% +mess right but you can do what you said + + + align:start position:0% +mess right but you can do what you said +an alternative would be to multiply it + + align:start position:0% +an alternative would be to multiply it + + + align:start position:0% +an alternative would be to multiply it +by another + + align:start position:0% +by another + + + align:start position:0% +by another +cosine which in the frequency domain is + + align:start position:0% +cosine which in the frequency domain is + + + align:start position:0% +cosine which in the frequency domain is +easy to think about it would just shift + + align:start position:0% +easy to think about it would just shift + + + align:start position:0% +easy to think about it would just shift +it back right so convolve with a pair of + + align:start position:0% +it back right so convolve with a pair of + + + align:start position:0% +it back right so convolve with a pair of +impulses to move something that was at + + align:start position:0% +impulses to move something that was at + + + align:start position:0% +impulses to move something that was at +DC out to some high frequency convolve + + align:start position:0% +DC out to some high frequency convolve + + + align:start position:0% +DC out to some high frequency convolve +again to take the thing that was high + + align:start position:0% +again to take the thing that was high + + + align:start position:0% +again to take the thing that was high +frequency and bring it back to DC and + + align:start position:0% +frequency and bring it back to DC and + + + align:start position:0% +frequency and bring it back to DC and +you can think about that in either uh + + align:start position:0% +you can think about that in either uh + + + align:start position:0% +you can think about that in either uh +frequency or time it's easy to think + + align:start position:0% +frequency or time it's easy to think + + + align:start position:0% +frequency or time it's easy to think +about it in time if you think about it + + align:start position:0% +about it in time if you think about it + + + align:start position:0% +about it in time if you think about it +in time here we've got the product of + + align:start position:0% +in time here we've got the product of + + + align:start position:0% +in time here we've got the product of +two cosiness but the product of two + + align:start position:0% +two cosiness but the product of two + + + align:start position:0% +two cosiness but the product of two +cosiness is just half plus half the + + align:start position:0% +cosiness is just half plus half the + + + align:start position:0% +cosiness is just half plus half the +cosine of + + align:start position:0% +cosine of + + + align:start position:0% +cosine of +double well that's good right why is + + align:start position:0% +double well that's good right why is + + + align:start position:0% +double well that's good right why is +that good well you can if you multiply X + + align:start position:0% +that good well you can if you multiply X + + + align:start position:0% +that good well you can if you multiply X +of T by this this is a super high + + align:start position:0% +of T by this this is a super high + + + align:start position:0% +of T by this this is a super high +frequency if Omega C was a high + + align:start position:0% +frequency if Omega C was a high + + + align:start position:0% +frequency if Omega C was a high +frequency two Omega C is even higher + + align:start position:0% +frequency two Omega C is even higher + + + align:start position:0% +frequency two Omega C is even higher +so what you could do is remove x * half + + align:start position:0% +so what you could do is remove x * half + + + align:start position:0% +so what you could do is remove x * half +Co 2 Omega CT with a low pass filter + + align:start position:0% +Co 2 Omega CT with a low pass filter + + + align:start position:0% +Co 2 Omega CT with a low pass filter +right since Omega C is such a high + + align:start position:0% +right since Omega C is such a high + + + align:start position:0% +right since Omega C is such a high +frequency and that would just leave you + + align:start position:0% +frequency and that would just leave you + + + align:start position:0% +frequency and that would just leave you +with half the message which would be + + align:start position:0% +with half the message which would be + + + align:start position:0% +with half the message which would be +easy then to + + align:start position:0% +easy then to + + + align:start position:0% +easy then to +reconstruct because what you would do is + + align:start position:0% +reconstruct because what you would do is + + + align:start position:0% +reconstruct because what you would do is +just put it through a low pass filter + + align:start position:0% +just put it through a low pass filter + + + align:start position:0% +just put it through a low pass filter +and then multiply by two you can + + align:start position:0% +and then multiply by two you can + + + align:start position:0% +and then multiply by two you can +similarly think about the same thing in + + align:start position:0% +similarly think about the same thing in + + + align:start position:0% +similarly think about the same thing in +frequency if I took Y and convolved it + + align:start position:0% +frequency if I took Y and convolved it + + + align:start position:0% +frequency if I took Y and convolved it +If I multiply In Time by another cosine + + align:start position:0% +If I multiply In Time by another cosine + + + align:start position:0% +If I multiply In Time by another cosine +wave that second cosine wave is a pair + + align:start position:0% +wave that second cosine wave is a pair + + + align:start position:0% +wave that second cosine wave is a pair +of impulses one minus Omega C and one + + align:start position:0% +of impulses one minus Omega C and one + + + align:start position:0% +of impulses one minus Omega C and one +Omega C and now when I convolve the Y + + align:start position:0% +Omega C and now when I convolve the Y + + + align:start position:0% +Omega C and now when I convolve the Y +signal this one uh shifts these two + + align:start position:0% +signal this one uh shifts these two + + + align:start position:0% +signal this one uh shifts these two +up and this one shifts these two down + + align:start position:0% +up and this one shifts these two down + + + align:start position:0% +up and this one shifts these two down +and two of them land on top of each + + align:start position:0% + + + + align:start position:0% + +other and uh but each of these was only + + align:start position:0% +other and uh but each of these was only + + + align:start position:0% +other and uh but each of these was only +of height one + + align:start position:0% +of height one + + + align:start position:0% +of height one +half right so by Oiler expression I + + align:start position:0% +half right so by Oiler expression I + + + align:start position:0% +half right so by Oiler expression I +um cosine of something was half e to the + + align:start position:0% +um cosine of something was half e to the + + + align:start position:0% +um cosine of something was half e to the +whatever plus half e to the whatever so + + align:start position:0% +whatever plus half e to the whatever so + + + align:start position:0% +whatever plus half e to the whatever so +I got halves on each of those + + align:start position:0% +I got halves on each of those + + + align:start position:0% +I got halves on each of those +amplitudes so uh the result is then that + + align:start position:0% +amplitudes so uh the result is then that + + + align:start position:0% +amplitudes so uh the result is then that +I have to multiply the low frequency + + align:start position:0% +I have to multiply the low frequency + + + align:start position:0% +I have to multiply the low frequency +part by a factor of two to undo the the + + align:start position:0% +part by a factor of two to undo the the + + + align:start position:0% +part by a factor of two to undo the the +halves + + align:start position:0% + + + + align:start position:0% + +okay okay so this kind of a scheme is + + align:start position:0% +okay okay so this kind of a scheme is + + + align:start position:0% +okay okay so this kind of a scheme is +especially + + align:start position:0% +especially + + + align:start position:0% +especially +nice because you can scramble together + + align:start position:0% +nice because you can scramble together + + + align:start position:0% +nice because you can scramble together +multiple messages and still get them + + align:start position:0% +multiple messages and still get them + + + align:start position:0% +multiple messages and still get them +separated at the + + align:start position:0% +separated at the + + + align:start position:0% +separated at the +destination if you imagine + + align:start position:0% +destination if you imagine + + + align:start position:0% +destination if you imagine +having uh three similar + + align:start position:0% +having uh three similar + + + align:start position:0% +having uh three similar +transmitters that use their own Omega C + + align:start position:0% +transmitters that use their own Omega C + + + align:start position:0% +transmitters that use their own Omega C +so the first one uses Omega 1 Omega 2 + + align:start position:0% + + + + align:start position:0% + +omega3 so if each one of the + + align:start position:0% +omega3 so if each one of the + + + align:start position:0% +omega3 so if each one of the +transmitters had their own + + align:start position:0% +transmitters had their own + + + align:start position:0% +transmitters had their own +frequency and if the frequencies were + + align:start position:0% +frequency and if the frequencies were + + + align:start position:0% +frequency and if the frequencies were +far enough apart and if the frequencies + + align:start position:0% +far enough apart and if the frequencies + + + align:start position:0% +far enough apart and if the frequencies +were all big compared to the message + + align:start position:0% +were all big compared to the message + + + align:start position:0% +were all big compared to the message +frequency + + align:start position:0% +frequency + + + align:start position:0% +frequency +then you could combine them all and + + align:start position:0% +then you could combine them all and + + + align:start position:0% +then you could combine them all and +select out the one of + + align:start position:0% +select out the one of + + + align:start position:0% +select out the one of +Interest by tuning the + + align:start position:0% +Interest by tuning the + + + align:start position:0% +Interest by tuning the +receiver by + + align:start position:0% +receiver by + + + align:start position:0% +receiver by +choosing the demodulation frequency so + + align:start position:0% +choosing the demodulation frequency so + + + align:start position:0% +choosing the demodulation frequency so +now if the receiver chose Omega C equals + + align:start position:0% +now if the receiver chose Omega C equals + + + align:start position:0% +now if the receiver chose Omega C equals +Omega 1 you would decode message one if + + align:start position:0% +Omega 1 you would decode message one if + + + align:start position:0% +Omega 1 you would decode message one if +Omega C were Omega 2 You' decode message + + align:start position:0% +Omega C were Omega 2 You' decode message + + + align:start position:0% +Omega C were Omega 2 You' decode message +two and that's the principle uh and + + align:start position:0% +two and that's the principle uh and + + + align:start position:0% +two and that's the principle uh and +that's because the medium Works + + align:start position:0% +that's because the medium Works + + + align:start position:0% +that's because the medium Works +approximately linearly + + align:start position:0% +approximately linearly + + + align:start position:0% +approximately linearly +so if you launch multiple waves into the + + align:start position:0% +so if you launch multiple waves into the + + + align:start position:0% +so if you launch multiple waves into the +air you um + + align:start position:0% +air you um + + + align:start position:0% +air you um +uh I don't want to get too much into + + align:start position:0% +uh I don't want to get too much into + + + align:start position:0% +uh I don't want to get too much into +electromagnetic Theory so the presence + + align:start position:0% +electromagnetic Theory so the presence + + + align:start position:0% +electromagnetic Theory so the presence +of the antennas distort it from + + align:start position:0% +of the antennas distort it from + + + align:start position:0% +of the antennas distort it from +linearity but once the antennas are all + + align:start position:0% +linearity but once the antennas are all + + + align:start position:0% +linearity but once the antennas are all +there then it's a perfectly linear + + align:start position:0% +there then it's a perfectly linear + + + align:start position:0% +there then it's a perfectly linear +system and the sum of what gets into and + + align:start position:0% +system and the sum of what gets into and + + + align:start position:0% +system and the sum of what gets into and +the the thing that gets into the uh air + + align:start position:0% +the the thing that gets into the uh air + + + align:start position:0% +the the thing that gets into the uh air +as a result of a sum is the sum of the + + align:start position:0% +as a result of a sum is the sum of the + + + align:start position:0% +as a result of a sum is the sum of the +individual + + align:start position:0% +individual + + + align:start position:0% +individual +parts so uh the idea then is Illustrated + + align:start position:0% +parts so uh the idea then is Illustrated + + + align:start position:0% +parts so uh the idea then is Illustrated +here if I had + + align:start position:0% +here if I had + + + align:start position:0% +here if I had +uh three different messages represented + + align:start position:0% +uh three different messages represented + + + align:start position:0% +uh three different messages represented +by different style + + align:start position:0% +by different style + + + align:start position:0% +by different style +houses and each one of the messages was + + align:start position:0% +houses and each one of the messages was + + + align:start position:0% +houses and each one of the messages was +at a different frequency Omega 1 Omega 2 + + align:start position:0% +at a different frequency Omega 1 Omega 2 + + + align:start position:0% +at a different frequency Omega 1 Omega 2 +omega3 by tuning the Omega C of the + + align:start position:0% +omega3 by tuning the Omega C of the + + + align:start position:0% +omega3 by tuning the Omega C of the +receiver if I put Omega C at Omega one + + align:start position:0% +receiver if I put Omega C at Omega one + + + align:start position:0% +receiver if I put Omega C at Omega one +that would uh convolution of this one + + align:start position:0% +that would uh convolution of this one + + + align:start position:0% +that would uh convolution of this one +would suck this one up to + + align:start position:0% +would suck this one up to + + + align:start position:0% +would suck this one up to +here and by this one would lower that + + align:start position:0% +here and by this one would lower that + + + align:start position:0% +here and by this one would lower that +one down to there you get overlap of the + + align:start position:0% +one down to there you get overlap of the + + + align:start position:0% +one down to there you get overlap of the +of the lowest frequency p pair and so if + + align:start position:0% +of the lowest frequency p pair and so if + + + align:start position:0% +of the lowest frequency p pair and so if +you built a low pass filter of exactly + + align:start position:0% +you built a low pass filter of exactly + + + align:start position:0% +you built a low pass filter of exactly +the right width you would decode message + + align:start position:0% +the right width you would decode message + + + align:start position:0% +the right width you would decode message +one where if you just change the + + align:start position:0% +one where if you just change the + + + align:start position:0% +one where if you just change the +frequency of the + + align:start position:0% +frequency of the + + + align:start position:0% +frequency of the +demodulator if you make the demodulation + + align:start position:0% +demodulator if you make the demodulation + + + align:start position:0% +demodulator if you make the demodulation +frequency now be Omega 2 now the effect + + align:start position:0% +frequency now be Omega 2 now the effect + + + align:start position:0% +frequency now be Omega 2 now the effect +of Shifting that different amount means + + align:start position:0% +of Shifting that different amount means + + + align:start position:0% +of Shifting that different amount means +that the low pass filter recovers the + + align:start position:0% +that the low pass filter recovers the + + + align:start position:0% +that the low pass filter recovers the +message two rather than message + + align:start position:0% +message two rather than message + + + align:start position:0% +message two rather than message +one okay so that's the idea and in fact + + align:start position:0% +one okay so that's the idea and in fact + + + align:start position:0% +one okay so that's the idea and in fact +so that's the idea that we use in + + align:start position:0% +so that's the idea that we use in + + + align:start position:0% +so that's the idea that we use in +commercial AM radio and that was in fact + + align:start position:0% +commercial AM radio and that was in fact + + + align:start position:0% +commercial AM radio and that was in fact +a revolutionary + + align:start position:0% +a revolutionary + + + align:start position:0% +a revolutionary +idea that enabled people to think about + + align:start position:0% +idea that enabled people to think about + + + align:start position:0% +idea that enabled people to think about +for the first time a communication + + align:start position:0% +for the first time a communication + + + align:start position:0% +for the first time a communication +system that did a lot of things that + + align:start position:0% +system that did a lot of things that + + + align:start position:0% +system that did a lot of things that +were very different from previous + + align:start position:0% +were very different from previous + + + align:start position:0% +were very different from previous +communication systems in particular it + + align:start position:0% +communication systems in particular it + + + align:start position:0% +communication systems in particular it +went at the speed of + + align:start position:0% +went at the speed of + + + align:start position:0% +went at the speed of +light even more importantly or at least + + align:start position:0% +light even more importantly or at least + + + align:start position:0% +light even more importantly or at least +as important is the fact that it was a + + align:start position:0% +as important is the fact that it was a + + + align:start position:0% +as important is the fact that it was a +broadcast system so broadcast was uh an + + align:start position:0% +broadcast system so broadcast was uh an + + + align:start position:0% +broadcast system so broadcast was uh an +idea that was championed by David + + align:start position:0% +idea that was championed by David + + + align:start position:0% +idea that was championed by David +snof sarof was a + + align:start position:0% +snof sarof was a + + + align:start position:0% +snof sarof was a +Visionary he was the the person who was + + align:start position:0% +Visionary he was the the person who was + + + align:start position:0% +Visionary he was the the person who was +very excited about the idea of broadcast + + align:start position:0% +very excited about the idea of broadcast + + + align:start position:0% +very excited about the idea of broadcast +which is a little ironic because he got + + align:start position:0% +which is a little ironic because he got + + + align:start position:0% +which is a little ironic because he got +his start with Marone Mar anybody ever + + align:start position:0% +his start with Marone Mar anybody ever + + + align:start position:0% +his start with Marone Mar anybody ever +hear + + align:start position:0% +hear + + + align:start position:0% +hear +Marone good good you're supposed to have + + align:start position:0% +Marone good good you're supposed to have + + + align:start position:0% +Marone good good you're supposed to have +heard of Marone okay so he so sof got + + align:start position:0% +heard of Marone okay so he so sof got + + + align:start position:0% +heard of Marone okay so he so sof got +his start this is sof this is Marone uh + + align:start position:0% +his start this is sof this is Marone uh + + + align:start position:0% +his start this is sof this is Marone uh +sof got his start with Marone Marone + + align:start position:0% +sof got his start with Marone Marone + + + align:start position:0% +sof got his start with Marone Marone +made his + + align:start position:0% +made his + + + align:start position:0% +made his +mint with wireless telegraphy anybody + + align:start position:0% +mint with wireless telegraphy anybody + + + align:start position:0% +mint with wireless telegraphy anybody +hear ever hear of telegraphy of course + + align:start position:0% +hear ever hear of telegraphy of course + + + align:start position:0% +hear ever hear of telegraphy of course +not uh so telegraphy this that's + + align:start position:0% +not uh so telegraphy this that's + + + align:start position:0% +not uh so telegraphy this that's +Telegraph right shake your heads yes + + align:start position:0% +Telegraph right shake your heads yes + + + align:start position:0% +Telegraph right shake your heads yes +it's ancient I realize so Marone made + + align:start position:0% +it's ancient I realize so Marone made + + + align:start position:0% +it's ancient I realize so Marone made +his fortune with wireless telegraphy + + align:start position:0% +his fortune with wireless telegraphy + + + align:start position:0% +his fortune with wireless telegraphy +telegraphy was what we call point to + + align:start position:0% +telegraphy was what we call point to + + + align:start position:0% +telegraphy was what we call point to +point the idea in telegraphy was + + align:start position:0% +point the idea in telegraphy was + + + align:start position:0% +point the idea in telegraphy was +precisely the same as the idea aide of + + align:start position:0% +precisely the same as the idea aide of + + + align:start position:0% +precisely the same as the idea aide of +the US Post + + align:start position:0% +the US Post + + + align:start position:0% +the US Post +Office except it was at the speed of + + align:start position:0% +Office except it was at the speed of + + + align:start position:0% +Office except it was at the speed of +light or not quite the speed of light so + + align:start position:0% +light or not quite the speed of light so + + + align:start position:0% +light or not quite the speed of light so +the idea in the post office is you take + + align:start position:0% +the idea in the post office is you take + + + align:start position:0% +the idea in the post office is you take +a sheet of + + align:start position:0% +a sheet of + + + align:start position:0% +a sheet of +paper and do something to it that makes + + align:start position:0% +paper and do something to it that makes + + + align:start position:0% +paper and do something to it that makes +it magically appear at somebody else's + + align:start position:0% +it magically appear at somebody else's + + + align:start position:0% +it magically appear at somebody else's +place okay so point a communicated to + + align:start position:0% +place okay so point a communicated to + + + align:start position:0% +place okay so point a communicated to +point B telegraphy was precisely the + + align:start position:0% +point B telegraphy was precisely the + + + align:start position:0% +point B telegraphy was precisely the +same you take your sheet of paper to the + + align:start position:0% +same you take your sheet of paper to the + + + align:start position:0% +same you take your sheet of paper to the +telegraph office and somebody who's very + + align:start position:0% +telegraph office and somebody who's very + + + align:start position:0% +telegraph office and somebody who's very +skilled with with their hands or + + align:start position:0% +skilled with with their hands or + + + align:start position:0% +skilled with with their hands or +specifically with their + + align:start position:0% +specifically with their + + + align:start position:0% +specifically with their +finger uh would do something that caused + + align:start position:0% +finger uh would do something that caused + + + align:start position:0% +finger uh would do something that caused +that piece of paper to be regenerated + + align:start position:0% +that piece of paper to be regenerated + + + align:start position:0% +that piece of paper to be regenerated +hundreds of miles + + align:start position:0% +hundreds of miles + + + align:start position:0% +hundreds of miles +away then that piece of paper got + + align:start position:0% +away then that piece of paper got + + + align:start position:0% +away then that piece of paper got +delivered so message went from point A + + align:start position:0% +delivered so message went from point A + + + align:start position:0% +delivered so message went from point A +to point B okay so telegraphy came long + + align:start position:0% +to point B okay so telegraphy came long + + + align:start position:0% +to point B okay so telegraphy came long +before + + align:start position:0% +before + + + align:start position:0% +before +Marone and it was a revolution in how + + align:start position:0% +Marone and it was a revolution in how + + + align:start position:0% +Marone and it was a revolution in how +you do Communications but it was point + + align:start position:0% +you do Communications but it was point + + + align:start position:0% +you do Communications but it was point +to point one person sent one message to + + align:start position:0% +to point one person sent one message to + + + align:start position:0% +to point one person sent one message to +one person um + + align:start position:0% +one person um + + + align:start position:0% +one person um +um sarof got his uh start in newspaper + + align:start position:0% +um sarof got his uh start in newspaper + + + align:start position:0% +um sarof got his uh start in newspaper +business he was a uh Russian immigrant + + align:start position:0% +business he was a uh Russian immigrant + + + align:start position:0% +business he was a uh Russian immigrant +impoverished and had a a newspaper route + + align:start position:0% +impoverished and had a a newspaper route + + + align:start position:0% +impoverished and had a a newspaper route +as a kid and he was so ambitious uh + + align:start position:0% +as a kid and he was so ambitious uh + + + align:start position:0% +as a kid and he was so ambitious uh +newspapers are + + align:start position:0% +newspapers are + + + align:start position:0% +newspapers are +broadcast the idea in pointto point and + + align:start position:0% +broadcast the idea in pointto point and + + + align:start position:0% +broadcast the idea in pointto point and +broadcast are very different in + + align:start position:0% +broadcast are very different in + + + align:start position:0% +broadcast are very different in +broadcast you're allowed to spend a + + align:start position:0% +broadcast you're allowed to spend a + + + align:start position:0% +broadcast you're allowed to spend a +fortune on the transmitter the printing + + align:start position:0% +fortune on the transmitter the printing + + + align:start position:0% +fortune on the transmitter the printing +press but not on the thing that the + + align:start position:0% +press but not on the thing that the + + + align:start position:0% +press but not on the thing that the +individuals get the individuals get + + align:start position:0% +individuals get the individuals get + + + align:start position:0% +individuals get the individuals get +newsprint so the paper and the ink have + + align:start position:0% +newsprint so the paper and the ink have + + + align:start position:0% +newsprint so the paper and the ink have +to be + + align:start position:0% +to be + + + align:start position:0% +to be +cheap the printing press doesn't Okay so + + align:start position:0% +cheap the printing press doesn't Okay so + + + align:start position:0% +cheap the printing press doesn't Okay so +that was sof's + + align:start position:0% +that was sof's + + + align:start position:0% +that was sof's +background uh but so he was interested + + align:start position:0% +background uh but so he was interested + + + align:start position:0% +background uh but so he was interested +as a kid in broadcast in newspaper but + + align:start position:0% +as a kid in broadcast in newspaper but + + + align:start position:0% +as a kid in broadcast in newspaper but +then he got his reputation working for + + align:start position:0% +then he got his reputation working for + + + align:start position:0% +then he got his reputation working for +Marone in Wireless te telegraphy Marone + + align:start position:0% +Marone in Wireless te telegraphy Marone + + + align:start position:0% +Marone in Wireless te telegraphy Marone +the inventor of radio thought of a way + + align:start position:0% +the inventor of radio thought of a way + + + align:start position:0% +the inventor of radio thought of a way +of doing point-to-point + + align:start position:0% +of doing point-to-point + + + align:start position:0% +of doing point-to-point +telegraphy wirelessly via radio radio + + align:start position:0% +telegraphy wirelessly via radio radio + + + align:start position:0% +telegraphy wirelessly via radio radio +telegraphy and he sold it to um uh + + align:start position:0% +telegraphy and he sold it to um uh + + + align:start position:0% +telegraphy and he sold it to um uh +ships and stof made his reputation + + align:start position:0% +ships and stof made his reputation + + + align:start position:0% +ships and stof made his reputation +because he was the guy operating the + + align:start position:0% +because he was the guy operating the + + + align:start position:0% +because he was the guy operating the +radio telegraphy system at the Marone + + align:start position:0% +radio telegraphy system at the Marone + + + align:start position:0% +radio telegraphy system at the Marone +system at the Marone company when the + + align:start position:0% +system at the Marone company when the + + + align:start position:0% +system at the Marone company when the +Titanic + + align:start position:0% +Titanic + + + align:start position:0% +Titanic +sank uh everybody know about the Titanic + + align:start position:0% +sank uh everybody know about the Titanic + + + align:start position:0% +sank uh everybody know about the Titanic +right big ship + + align:start position:0% +right big ship + + + align:start position:0% +right big ship +sank um Mark uh so sarof uh stayed uh at + + align:start position:0% +sank um Mark uh so sarof uh stayed uh at + + + align:start position:0% +sank um Mark uh so sarof uh stayed uh at +the snof was known as an amazing uh + + align:start position:0% +the snof was known as an amazing uh + + + align:start position:0% +the snof was known as an amazing uh +telegraphy operator and he stayed at the + + align:start position:0% +telegraphy operator and he stayed at the + + + align:start position:0% +telegraphy operator and he stayed at the +station for 72 consecutive hours getting + + align:start position:0% +station for 72 consecutive hours getting + + + align:start position:0% +station for 72 consecutive hours getting +emergency messages from the Titanic + + align:start position:0% +emergency messages from the Titanic + + + align:start position:0% +emergency messages from the Titanic +telling everybody everything that he + + align:start position:0% +telling everybody everything that he + + + align:start position:0% +telling everybody everything that he +could trying to tell them the situation + + align:start position:0% +could trying to tell them the situation + + + align:start position:0% +could trying to tell them the situation +whose family was in good shape whose + + align:start position:0% +whose family was in good shape whose + + + align:start position:0% +whose family was in good shape whose +family was not in good shape it had an + + align:start position:0% +family was not in good shape it had an + + + align:start position:0% +family was not in good shape it had an +enormous + + align:start position:0% +enormous + + + align:start position:0% +enormous +impact big enough that Congress made a + + align:start position:0% +impact big enough that Congress made a + + + align:start position:0% +impact big enough that Congress made a +law saying that every ship had to have + + align:start position:0% +law saying that every ship had to have + + + align:start position:0% +law saying that every ship had to have +wireless telegraphy now that made Marone + + align:start position:0% +wireless telegraphy now that made Marone + + + align:start position:0% +wireless telegraphy now that made Marone +extremely rich and it uh indirectly made + + align:start position:0% +extremely rich and it uh indirectly made + + + align:start position:0% +extremely rich and it uh indirectly made +sarof extremely rich too sarof then got + + align:start position:0% +sarof extremely rich too sarof then got + + + align:start position:0% +sarof extremely rich too sarof then got +very interested in uh + + align:start position:0% +very interested in uh + + + align:start position:0% +very interested in uh +extending the idea of radio which then + + align:start position:0% +extending the idea of radio which then + + + align:start position:0% +extending the idea of radio which then +was pointto point to + + align:start position:0% +was pointto point to + + + align:start position:0% +was pointto point to +broadcast so the idea was to somehow he + + align:start position:0% +broadcast so the idea was to somehow he + + + align:start position:0% +broadcast so the idea was to somehow he +called it a radio music box somehow it + + align:start position:0% +called it a radio music box somehow it + + + align:start position:0% +called it a radio music box somehow it +was supposed to be like a newspaper but + + align:start position:0% +was supposed to be like a newspaper but + + + align:start position:0% +was supposed to be like a newspaper but +at the speed of light so the idea was to + + align:start position:0% +at the speed of light so the idea was to + + + align:start position:0% +at the speed of light so the idea was to +somehow make Mass + + align:start position:0% +somehow make Mass + + + align:start position:0% +somehow make Mass +consumption of radio at the time radio + + align:start position:0% +consumption of radio at the time radio + + + align:start position:0% +consumption of radio at the time radio +was per + + align:start position:0% +was per + + + align:start position:0% +was per +ship point to point so you have the + + align:start position:0% +ship point to point so you have the + + + align:start position:0% +ship point to point so you have the +landbased station talking to ship a or + + align:start position:0% +landbased station talking to ship a or + + + align:start position:0% +landbased station talking to ship a or +the landbased station talking to ship b + + align:start position:0% +the landbased station talking to ship b + + + align:start position:0% +the landbased station talking to ship b +or ship a talking to ship B but it was + + align:start position:0% +or ship a talking to ship B but it was + + + align:start position:0% +or ship a talking to ship B but it was +all point to point sof's idea was let's + + align:start position:0% +all point to point sof's idea was let's + + + align:start position:0% +all point to point sof's idea was let's +make a newspaper out of this the key to + + align:start position:0% +make a newspaper out of this the key to + + + align:start position:0% +make a newspaper out of this the key to +doing that was making a cheap + + align:start position:0% +doing that was making a cheap + + + align:start position:0% +doing that was making a cheap +Receiver right it's like newsprint right + + align:start position:0% +Receiver right it's like newsprint right + + + align:start position:0% +Receiver right it's like newsprint right +the printer can cost a + + align:start position:0% +the printer can cost a + + + align:start position:0% +the printer can cost a +mint the transmitter for radio um uh + + align:start position:0% +mint the transmitter for radio um uh + + + align:start position:0% +mint the transmitter for radio um uh +radio broadcast music is allowed to cost + + align:start position:0% +radio broadcast music is allowed to cost + + + align:start position:0% +radio broadcast music is allowed to cost +a mint but the receivers are not allowed + + align:start position:0% +a mint but the receivers are not allowed + + + align:start position:0% +a mint but the receivers are not allowed +to cost a mint that's like the + + align:start position:0% +to cost a mint that's like the + + + align:start position:0% +to cost a mint that's like the +newsprint so the trick was to make an + + align:start position:0% +newsprint so the trick was to make an + + + align:start position:0% +newsprint so the trick was to make an +inexpensive receiver the problem with + + align:start position:0% +inexpensive receiver the problem with + + + align:start position:0% +inexpensive receiver the problem with +making an inex expensive receiver is + + align:start position:0% +making an inex expensive receiver is + + + align:start position:0% +making an inex expensive receiver is +that the scheme that we just talked + + align:start position:0% +that the scheme that we just talked + + + align:start position:0% +that the scheme that we just talked +about + + align:start position:0% +about + + + align:start position:0% +about +uh where you derive the where you decode + + align:start position:0% +uh where you derive the where you decode + + + align:start position:0% +uh where you derive the where you decode +the signal by multiplying a second time + + align:start position:0% +the signal by multiplying a second time + + + align:start position:0% +the signal by multiplying a second time +by multiplying by Co Omega CT Omega C + + align:start position:0% +by multiplying by Co Omega CT Omega C + + + align:start position:0% +by multiplying by Co Omega CT Omega C +chosen to be the frequency that you want + + align:start position:0% +chosen to be the frequency that you want + + + align:start position:0% +chosen to be the frequency that you want +to listen to problem with that that's + + align:start position:0% +to listen to problem with that that's + + + align:start position:0% +to listen to problem with that that's +called synchronous demodulation problem + + align:start position:0% +called synchronous demodulation problem + + + align:start position:0% +called synchronous demodulation problem +with that is that you've got to be + + align:start position:0% +with that is that you've got to be + + + align:start position:0% +with that is that you've got to be +exactly + + align:start position:0% +exactly + + + align:start position:0% +exactly +synchronized if you want to listen to + + align:start position:0% +synchronized if you want to listen to + + + align:start position:0% +synchronized if you want to listen to +the message at Omega 2 Omega C must + + align:start position:0% +the message at Omega 2 Omega C must + + + align:start position:0% +the message at Omega 2 Omega C must +equal Omega 2 not omega 2 + + + align:start position:0% +equal Omega 2 not omega 2 + + + + align:start position:0% +equal Omega 2 not omega 2 + +3 okay so if you want to listen to a + + align:start position:0% +3 okay so if you want to listen to a + + + align:start position:0% +3 okay so if you want to listen to a +particular frequency at a to a + + align:start position:0% +particular frequency at a to a + + + align:start position:0% +particular frequency at a to a +particular message you had to have the + + align:start position:0% +particular message you had to have the + + + align:start position:0% +particular message you had to have the +frequency chosen to match the carrier of + + align:start position:0% +frequency chosen to match the carrier of + + + align:start position:0% +frequency chosen to match the carrier of +the message you wanted to listen + + align:start position:0% +the message you wanted to listen + + + align:start position:0% +the message you wanted to listen +to today that's not so hard the way we + + align:start position:0% +to today that's not so hard the way we + + + align:start position:0% +to today that's not so hard the way we +would make frequencies today is with a + + align:start position:0% +would make frequencies today is with a + + + align:start position:0% +would make frequencies today is with a +crystal crystals are great because the + + align:start position:0% +crystal crystals are great because the + + + align:start position:0% +crystal crystals are great because the +frequencies are determined by the + + align:start position:0% +frequencies are determined by the + + + align:start position:0% +frequencies are determined by the +distances in Crystal lates which are + + align:start position:0% +distances in Crystal lates which are + + + align:start position:0% +distances in Crystal lates which are +determined by nanomechanical processes + + align:start position:0% +determined by nanomechanical processes + + + align:start position:0% +determined by nanomechanical processes +to very precisely and in fact we can + + align:start position:0% +to very precisely and in fact we can + + + align:start position:0% +to very precisely and in fact we can +make crystals with no problem with uh + + align:start position:0% +make crystals with no problem with uh + + + align:start position:0% +make crystals with no problem with uh +frequency resolutions of 10us 7 even 10 + + align:start position:0% +frequency resolutions of 10us 7 even 10 + + + align:start position:0% +frequency resolutions of 10us 7 even 10 +Theus 8 so the errors are very small + + align:start position:0% +Theus 8 so the errors are very small + + + align:start position:0% +Theus 8 so the errors are very small +compared to the U frequencies that we're + + align:start position:0% +compared to the U frequencies that we're + + + align:start position:0% +compared to the U frequencies that we're +trying to generate even that wouldn't be + + align:start position:0% +trying to generate even that wouldn't be + + + align:start position:0% +trying to generate even that wouldn't be +good + + align:start position:0% +good + + + align:start position:0% +good +enough so back then this is uh so sof + + align:start position:0% +enough so back then this is uh so sof + + + align:start position:0% +enough so back then this is uh so sof +was working back in the + + align:start position:0% +was working back in the + + + align:start position:0% +was working back in the +1900s back then they couldn't possibly + + align:start position:0% +1900s back then they couldn't possibly + + + align:start position:0% +1900s back then they couldn't possibly +do 10us 8 Precision they were doing + + align:start position:0% +do 10us 8 Precision they were doing + + + align:start position:0% +do 10us 8 Precision they were doing +something more like 10us 2 precision + + align:start position:0% +something more like 10us 2 precision + + + align:start position:0% +something more like 10us 2 precision +they didn't have a Technology based on + + align:start position:0% +they didn't have a Technology based on + + + align:start position:0% +they didn't have a Technology based on +crystals so + + align:start position:0% +crystals so + + + align:start position:0% +crystals so +um they so it would have been impossible + + align:start position:0% +um they so it would have been impossible + + + align:start position:0% +um they so it would have been impossible +to match even to within a factor of 10 + + align:start position:0% +to match even to within a factor of 10 + + + align:start position:0% +to match even to within a factor of 10 +the minus 3 but even if they could have + + align:start position:0% +the minus 3 but even if they could have + + + align:start position:0% +the minus 3 but even if they could have +matched to within 10 the minus8 which we + + align:start position:0% +matched to within 10 the minus8 which we + + + align:start position:0% +matched to within 10 the minus8 which we +could today even that wouldn't work + + align:start position:0% +could today even that wouldn't work + + + align:start position:0% +could today even that wouldn't work +because not only does the frequency have + + align:start position:0% +because not only does the frequency have + + + align:start position:0% +because not only does the frequency have +to match the phase has to + + align:start position:0% +to match the phase has to + + + align:start position:0% +to match the phase has to +match so if you're multiplying by a CO + + align:start position:0% +match so if you're multiplying by a CO + + + align:start position:0% +match so if you're multiplying by a CO +Omega CT and you want Omega C to be + + align:start position:0% +Omega CT and you want Omega C to be + + + align:start position:0% +Omega CT and you want Omega C to be +Omega 2 it better actually be the cosine + + align:start position:0% +Omega 2 it better actually be the cosine + + + align:start position:0% +Omega 2 it better actually be the cosine +of Omega 2 and not the of Omega 2 and Co + + align:start position:0% +of Omega 2 and not the of Omega 2 and Co + + + align:start position:0% +of Omega 2 and not the of Omega 2 and Co +differ by a phase so the question is + + align:start position:0% +differ by a phase so the question is + + + align:start position:0% +differ by a phase so the question is +what's the effect of + + align:start position:0% + + + + align:start position:0% + +phase when you're trying to demodulate a + + align:start position:0% + + + + align:start position:0% + +signal so look at your + + align:start position:0% +signal so look at your + + + align:start position:0% +signal so look at your +neighbor what would happen if you tried + + align:start position:0% +neighbor what would happen if you tried + + + align:start position:0% +neighbor what would happen if you tried +to demodulate by precisely the right + + align:start position:0% +to demodulate by precisely the right + + + align:start position:0% +to demodulate by precisely the right +frequency but you were slipped by + + align:start position:0% + + + + align:start position:0% + +phase e + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +okay so what would happen if there was a + + align:start position:0% +okay so what would happen if there was a + + + align:start position:0% +okay so what would happen if there was a +phase shift between this carrier that + + align:start position:0% +phase shift between this carrier that + + + align:start position:0% +phase shift between this carrier that +was modulating the + + align:start position:0% +was modulating the + + + align:start position:0% +was modulating the +signal and the carrier that is + + align:start position:0% +signal and the carrier that is + + + align:start position:0% +signal and the carrier that is +demodulating the signal what would + + align:start position:0% +demodulating the signal what would + + + align:start position:0% +demodulating the signal what would +happen if there's a phase shift of five + + align:start position:0% +happen if there's a phase shift of five + + + align:start position:0% +happen if there's a phase shift of five +between those + + align:start position:0% +between those + + + align:start position:0% +between those +two what's the effect of five not being + + align:start position:0% +two what's the effect of five not being + + + align:start position:0% +two what's the effect of five not being +zero ideally five would be zero right + + align:start position:0% +zero ideally five would be zero right + + + align:start position:0% +zero ideally five would be zero right +ideally five would be zero what would + + align:start position:0% +ideally five would be zero what would + + + align:start position:0% +ideally five would be zero what would +happen if I were not + + align:start position:0% + + + + align:start position:0% + +zero okay you did all that talking and + + align:start position:0% +zero okay you did all that talking and + + + align:start position:0% +zero okay you did all that talking and +you don't + + align:start position:0% +you don't + + + align:start position:0% +you don't +have yes so like the low pass filter yes + + align:start position:0% +have yes so like the low pass filter yes + + + align:start position:0% +have yes so like the low pass filter yes +of like two will not work in like it + + align:start position:0% +of like two will not work in like it + + + align:start position:0% +of like two will not work in like it +will be either it will be a lot smaller + + align:start position:0% +will be either it will be a lot smaller + + + align:start position:0% +will be either it will be a lot smaller +than what you wanted to done like half + + align:start position:0% +than what you wanted to done like half + + + align:start position:0% +than what you wanted to done like half +so that's exactly right so the the + + align:start position:0% +so that's exactly right so the the + + + align:start position:0% +so that's exactly right so the the +effect of fi if you think about uh so + + align:start position:0% +effect of fi if you think about uh so + + + align:start position:0% +effect of fi if you think about uh so +now you have cosine of some omega C and + + align:start position:0% +now you have cosine of some omega C and + + + align:start position:0% +now you have cosine of some omega C and +Co Omega c c but plus 5 so you have Co a + + align:start position:0% +Co Omega c c but plus 5 so you have Co a + + + align:start position:0% +Co Omega c c but plus 5 so you have Co a +CO B right so that gives you uh the co + + align:start position:0% +CO B right so that gives you uh the co + + + align:start position:0% +CO B right so that gives you uh the co +of the difference and the co of the sum + + align:start position:0% +of the difference and the co of the sum + + + align:start position:0% +of the difference and the co of the sum +right the co of the difference was + + align:start position:0% +right the co of the difference was + + + align:start position:0% +right the co of the difference was +supposed to be the co the difference was + + align:start position:0% +supposed to be the co the difference was + + + align:start position:0% +supposed to be the co the difference was +supposed to be zero the co of the + + align:start position:0% +supposed to be zero the co of the + + + align:start position:0% +supposed to be zero the co of the +difference would be the co of zero it + + align:start position:0% +difference would be the co of zero it + + + align:start position:0% +difference would be the co of zero it +should be one and that's where the half + + align:start position:0% +should be one and that's where the half + + + align:start position:0% +should be one and that's where the half +came + + align:start position:0% +came + + + align:start position:0% +came +from but now the difference isn't zero + + align:start position:0% +from but now the difference isn't zero + + + align:start position:0% +from but now the difference isn't zero +anymore + + align:start position:0% +anymore + + + align:start position:0% +anymore +so instead of getting uh a half Co of + + align:start position:0% +so instead of getting uh a half Co of + + + align:start position:0% +so instead of getting uh a half Co of +zero we get half Co of f which means + + align:start position:0% +zero we get half Co of f which means + + + align:start position:0% +zero we get half Co of f which means +that if f is a constant you just get the + + align:start position:0% +that if f is a constant you just get the + + + align:start position:0% +that if f is a constant you just get the +wrong + + align:start position:0% +wrong + + + align:start position:0% +wrong +amplitude but if fi is a slowly varying + + align:start position:0% +amplitude but if fi is a slowly varying + + + align:start position:0% +amplitude but if fi is a slowly varying +signal then uh which it would be even if + + align:start position:0% +signal then uh which it would be even if + + + align:start position:0% +signal then uh which it would be even if +you had a a frequency reliability of one + + align:start position:0% +you had a a frequency reliability of one + + + align:start position:0% +you had a a frequency reliability of one +part in 10 minus + + align:start position:0% +part in 10 minus + + + align:start position:0% +part in 10 minus +7 one way of thinking about that would + + align:start position:0% +7 one way of thinking about that would + + + align:start position:0% +7 one way of thinking about that would +be that there's a slowly varying phase + + align:start position:0% +be that there's a slowly varying phase + + + align:start position:0% +be that there's a slowly varying phase +the effect of the slowly varying phase + + align:start position:0% +the effect of the slowly varying phase + + + align:start position:0% +the effect of the slowly varying phase +would be to make the + + align:start position:0% +would be to make the + + + align:start position:0% +would be to make the +amplitude uh vary with time so we call + + align:start position:0% +amplitude uh vary with time so we call + + + align:start position:0% +amplitude uh vary with time so we call +that fading and it would be a very uh + + align:start position:0% +that fading and it would be a very uh + + + align:start position:0% +that fading and it would be a very uh +distracting thing to have happen so this + + align:start position:0% +distracting thing to have happen so this + + + align:start position:0% +distracting thing to have happen so this +kind of a technology would even be + + align:start position:0% +kind of a technology would even be + + + align:start position:0% +kind of a technology would even be +difficult today when we can match + + align:start position:0% +difficult today when we can match + + + align:start position:0% +difficult today when we can match +frequencies very well it was completely + + align:start position:0% +frequencies very well it was completely + + + align:start position:0% +frequencies very well it was completely +out of the question back in the 1900s + + align:start position:0% +out of the question back in the 1900s + + + align:start position:0% +out of the question back in the 1900s +when they couldn't match frequencies + + align:start position:0% +when they couldn't match frequencies + + + align:start position:0% +when they couldn't match frequencies +that well so the trick was to not only + + align:start position:0% +that well so the trick was to not only + + + align:start position:0% +that well so the trick was to not only +send the message but also send the + + align:start position:0% +send the message but also send the + + + align:start position:0% +send the message but also send the +carrier + + align:start position:0% + + + + align:start position:0% + +so ideally when we first talked about + + align:start position:0% +so ideally when we first talked about + + + align:start position:0% +so ideally when we first talked about +modulation there is no C path all you do + + align:start position:0% +modulation there is no C path all you do + + + align:start position:0% +modulation there is no C path all you do +is you take the signal and you modulate + + align:start position:0% +is you take the signal and you modulate + + + align:start position:0% +is you take the signal and you modulate +it by a carrier and you send that out on + + align:start position:0% +it by a carrier and you send that out on + + + align:start position:0% +it by a carrier and you send that out on +the antenna now instead add on a little + + align:start position:0% +the antenna now instead add on a little + + + align:start position:0% +the antenna now instead add on a little +bit of the + + align:start position:0% +bit of the + + + align:start position:0% +bit of the +carrier that way what's in the air is + + align:start position:0% +carrier that way what's in the air is + + + align:start position:0% +carrier that way what's in the air is +the carrier and the message so now when + + align:start position:0% +the carrier and the message so now when + + + align:start position:0% +the carrier and the message so now when +you receive it somehow if you can + + align:start position:0% +you receive it somehow if you can + + + align:start position:0% +you receive it somehow if you can +receive the carrier you can use the + + align:start position:0% +receive the carrier you can use the + + + align:start position:0% +receive the carrier you can use the +carrier to tell you information about + + align:start position:0% +carrier to tell you information about + + + align:start position:0% +carrier to tell you information about +not only the frequency but also the + + align:start position:0% +not only the frequency but also the + + + align:start position:0% +not only the frequency but also the +phase of the carrier and you can use + + align:start position:0% +phase of the carrier and you can use + + + align:start position:0% +phase of the carrier and you can use +that then to demodulate the message + + align:start position:0% +that then to demodulate the message + + + align:start position:0% +that then to demodulate the message +that's the idea notice that uh adding in + + align:start position:0% +that's the idea notice that uh adding in + + + align:start position:0% +that's the idea notice that uh adding in +a little bit C of the carrier is + + align:start position:0% +a little bit C of the carrier is + + + align:start position:0% +a little bit C of the carrier is +precisely the same as adding a constant + + align:start position:0% +precisely the same as adding a constant + + + align:start position:0% +precisely the same as adding a constant +to the + + align:start position:0% +to the + + + align:start position:0% +to the +message before you modulate + + align:start position:0% +message before you modulate + + + align:start position:0% +message before you modulate +mathematically identical and that gives + + align:start position:0% +mathematically identical and that gives + + + align:start position:0% +mathematically identical and that gives +an easy way of thinking about the effect + + align:start position:0% +an easy way of thinking about the effect + + + align:start position:0% +an easy way of thinking about the effect +of this + + align:start position:0% +of this + + + align:start position:0% +of this +carrier if you think about the message + + align:start position:0% +carrier if you think about the message + + + align:start position:0% +carrier if you think about the message +added to C and if C is big + + align:start position:0% +added to C and if C is big + + + align:start position:0% +added to C and if C is big +enough you can make the carry you can + + align:start position:0% +enough you can make the carry you can + + + align:start position:0% +enough you can make the carry you can +make the message positive + + align:start position:0% +make the message positive + + + align:start position:0% +make the message positive +only you remember before in the previous + + align:start position:0% +only you remember before in the previous + + + align:start position:0% +only you remember before in the previous +illustration uh every time the message + + align:start position:0% +illustration uh every time the message + + + align:start position:0% +illustration uh every time the message +went through zero which might happen + + align:start position:0% +went through zero which might happen + + + align:start position:0% +went through zero which might happen +here the the uh modulated message went + + align:start position:0% +here the the uh modulated message went + + + align:start position:0% +here the the uh modulated message went +through zero also which means that sign + + align:start position:0% +through zero also which means that sign + + + align:start position:0% +through zero also which means that sign +changes were affected by 180° face + + align:start position:0% +changes were affected by 180° face + + + align:start position:0% +changes were affected by 180° face +shifts of the carrier which was kind of + + align:start position:0% +shifts of the carrier which was kind of + + + align:start position:0% +shifts of the carrier which was kind of +a subtle thing so now the message appear + + align:start position:0% +a subtle thing so now the message appear + + + align:start position:0% +a subtle thing so now the message appear +entirely as the positive + + align:start position:0% +entirely as the positive + + + align:start position:0% +entirely as the positive +envelope of the carrier well that's nice + + align:start position:0% +envelope of the carrier well that's nice + + + align:start position:0% +envelope of the carrier well that's nice +because that makes it very easy to + + align:start position:0% +because that makes it very easy to + + + align:start position:0% +because that makes it very easy to +decode in a way that has uh no + + align:start position:0% +decode in a way that has uh no + + + align:start position:0% +decode in a way that has uh no +dependence + + align:start position:0% +dependence + + + align:start position:0% +dependence +whatever on the carrier frequency if the + + align:start position:0% +whatever on the carrier frequency if the + + + align:start position:0% +whatever on the carrier frequency if the +carrier frequency is big enough you can + + align:start position:0% +carrier frequency is big enough you can + + + align:start position:0% +carrier frequency is big enough you can +uh if the frequency of the carrier is + + align:start position:0% +uh if the frequency of the carrier is + + + align:start position:0% +uh if the frequency of the carrier is +sufficiently larger than the maximum + + align:start position:0% +sufficiently larger than the maximum + + + align:start position:0% +sufficiently larger than the maximum +frequency of the message there's a + + align:start position:0% +frequency of the message there's a + + + align:start position:0% +frequency of the message there's a +trivial way to decode such a such a + + align:start position:0% +trivial way to decode such a such a + + + align:start position:0% +trivial way to decode such a such a +system uh with a nonlinear Circuit of + + align:start position:0% +system uh with a nonlinear Circuit of + + + align:start position:0% +system uh with a nonlinear Circuit of +this type what's intended here is that + + align:start position:0% +this type what's intended here is that + + + align:start position:0% +this type what's intended here is that +you take the message that's received + + align:start position:0% +you take the message that's received + + + align:start position:0% +you take the message that's received +from the + + align:start position:0% +from the + + + align:start position:0% +from the +antenna re reconstruct Y which is + + align:start position:0% +antenna re reconstruct Y which is + + + align:start position:0% +antenna re reconstruct Y which is +intended to be the output + + align:start position:0% +intended to be the output + + + align:start position:0% +intended to be the output +message such that if Z the signal on the + + align:start position:0% +message such that if Z the signal on the + + + align:start position:0% +message such that if Z the signal on the +antenna exceeds the current value of the + + align:start position:0% +antenna exceeds the current value of the + + + align:start position:0% +antenna exceeds the current value of the +message the diode comes + + align:start position:0% +message the diode comes + + + align:start position:0% +message the diode comes +on and that makes the Blue Line the + + align:start position:0% +on and that makes the Blue Line the + + + align:start position:0% +on and that makes the Blue Line the +decoded signal rapidly go back up to the + + align:start position:0% +decoded signal rapidly go back up to the + + + align:start position:0% +decoded signal rapidly go back up to the +red line the thing that's coming off the + + align:start position:0% +red line the thing that's coming off the + + + align:start position:0% +red line the thing that's coming off the +antenna + + align:start position:0% +antenna + + + align:start position:0% +antenna +but if the antenna signal shrinks below + + align:start position:0% +but if the antenna signal shrinks below + + + align:start position:0% +but if the antenna signal shrinks below +the Blue Line let the Blue Line + + align:start position:0% +the Blue Line let the Blue Line + + + align:start position:0% +the Blue Line let the Blue Line +discharge because there's a an RC Decay + + align:start position:0% +discharge because there's a an RC Decay + + + align:start position:0% +discharge because there's a an RC Decay +constant so there's a fast attack + + align:start position:0% +constant so there's a fast attack + + + align:start position:0% +constant so there's a fast attack +through the diode so that the blue + + align:start position:0% +through the diode so that the blue + + + align:start position:0% +through the diode so that the blue +quickly goes to the peak value of the + + align:start position:0% +quickly goes to the peak value of the + + + align:start position:0% +quickly goes to the peak value of the +red and slowly decays back towards zero + + align:start position:0% +red and slowly decays back towards zero + + + align:start position:0% +red and slowly decays back towards zero +the result is that if the frequencies + + align:start position:0% +the result is that if the frequencies + + + align:start position:0% +the result is that if the frequencies +the the difference in frequency between + + align:start position:0% +the the difference in frequency between + + + align:start position:0% +the the difference in frequency between +the carrier frequency and the message + + align:start position:0% +the carrier frequency and the message + + + align:start position:0% +the carrier frequency and the message +frequencies is sufficiently large you + + align:start position:0% +frequencies is sufficiently large you + + + align:start position:0% +frequencies is sufficiently large you +can effectively separate the blue from + + align:start position:0% +can effectively separate the blue from + + + align:start position:0% +can effectively separate the blue from +the red with a very simple circuit and + + align:start position:0% +the red with a very simple circuit and + + + align:start position:0% +the red with a very simple circuit and +that's the way they do it or that's the + + align:start position:0% +that's the way they do it or that's the + + + align:start position:0% +that's the way they do it or that's the +way they did it in in u the early 1900s + + align:start position:0% +way they did it in in u the early 1900s + + + align:start position:0% +way they did it in in u the early 1900s +but there's still a problem with that + + align:start position:0% +but there's still a problem with that + + + align:start position:0% +but there's still a problem with that +the problem is that the + + align:start position:0% +the problem is that the + + + align:start position:0% +the problem is that the +messages audio of the type that I'm + + align:start position:0% +messages audio of the type that I'm + + + align:start position:0% +messages audio of the type that I'm +speaking speech is characterized by an + + align:start position:0% +speaking speech is characterized by an + + + align:start position:0% +speaking speech is characterized by an +enormous Peak to average + + align:start position:0% +enormous Peak to average + + + align:start position:0% +enormous Peak to average +ratio the strongest pressures that are + + align:start position:0% +ratio the strongest pressures that are + + + align:start position:0% +ratio the strongest pressures that are +generated by speech are enormously more + + align:start position:0% +generated by speech are enormously more + + + align:start position:0% +generated by speech are enormously more +powerful than the average pressure + + align:start position:0% +powerful than the average pressure + + + align:start position:0% +powerful than the average pressure +that's generated in speech you can see + + align:start position:0% +that's generated in speech you can see + + + align:start position:0% +that's generated in speech you can see +that in this diagram by these Peaks + + align:start position:0% +that in this diagram by these Peaks + + + align:start position:0% +that in this diagram by these Peaks +right there's several things that + + align:start position:0% +right there's several things that + + + align:start position:0% +right there's several things that +generate Peaks Peaks are generated at + + align:start position:0% +generate Peaks Peaks are generated at + + + align:start position:0% +generate Peaks Peaks are generated at +about uh 60 or 70 Hertz by my vocal + + align:start position:0% +about uh 60 or 70 Hertz by my vocal + + + align:start position:0% +about uh 60 or 70 Hertz by my vocal +cords but they're also generated by my + + align:start position:0% +cords but they're also generated by my + + + align:start position:0% +cords but they're also generated by my +lips in plosives right when I do + + align:start position:0% +lips in plosives right when I do + + + align:start position:0% +lips in plosives right when I do +aive there's a sudden jump in the + + align:start position:0% +aive there's a sudden jump in the + + + align:start position:0% +aive there's a sudden jump in the +instantaneous frequency that's not there + + align:start position:0% +instantaneous frequency that's not there + + + align:start position:0% +instantaneous frequency that's not there +on average and for normal speech that + + align:start position:0% +on average and for normal speech that + + + align:start position:0% +on average and for normal speech that +ratio can be as high as 35 + + align:start position:0% +ratio can be as high as 35 + + + align:start position:0% +ratio can be as high as 35 +to1 35 to1 big deal problem is that + + align:start position:0% +to1 35 to1 big deal problem is that + + + align:start position:0% +to1 35 to1 big deal problem is that +power goes like the square of voltage so + + align:start position:0% +power goes like the square of voltage so + + + align:start position:0% +power goes like the square of voltage so +35 to1 becomes a th to one It Takes a + + align:start position:0% +35 to1 becomes a th to one It Takes a + + + align:start position:0% +35 to1 becomes a th to one It Takes a +thousand times more + + align:start position:0% +thousand times more + + + align:start position:0% +thousand times more +energy to code the Peaks than it does to + + align:start position:0% +energy to code the Peaks than it does to + + + align:start position:0% +energy to code the Peaks than it does to +code the average and the problem with + + align:start position:0% +code the average and the problem with + + + align:start position:0% +code the average and the problem with +that is that in this coding scheme that + + align:start position:0% +that is that in this coding scheme that + + + align:start position:0% +that is that in this coding scheme that +we talked + + align:start position:0% +we talked + + + align:start position:0% +we talked +about you have to add a constant that is + + align:start position:0% +about you have to add a constant that is + + + align:start position:0% +about you have to add a constant that is +big enough so that the signal never goes + + align:start position:0% +big enough so that the signal never goes + + + align:start position:0% +big enough so that the signal never goes +negative so the constant that you add + + align:start position:0% +negative so the constant that you add + + + align:start position:0% +negative so the constant that you add +has to go in proportion to the peak + + align:start position:0% +has to go in proportion to the peak + + + align:start position:0% +has to go in proportion to the peak +value so you end up transmitting almost + + align:start position:0% +value so you end up transmitting almost + + + align:start position:0% +value so you end up transmitting almost +all of your + + align:start position:0% +all of your + + + align:start position:0% +all of your +power 1,00 to one by the ratio of 1,00 + + align:start position:0% +power 1,00 to one by the ratio of 1,00 + + + align:start position:0% +power 1,00 to one by the ratio of 1,00 +to one that's the amount of power that + + align:start position:0% +to one that's the amount of power that + + + align:start position:0% +to one that's the amount of power that +gets used to transmit the carrier + + align:start position:0% +gets used to transmit the carrier + + + align:start position:0% +gets used to transmit the carrier +compared to the message well that's a + + align:start position:0% +compared to the message well that's a + + + align:start position:0% +compared to the message well that's a +terrible scheme if what we were trying + + align:start position:0% +terrible scheme if what we were trying + + + align:start position:0% +terrible scheme if what we were trying +to do is point to point imagine your + + align:start position:0% +to do is point to point imagine your + + + align:start position:0% +to do is point to point imagine your +cell + + align:start position:0% +cell + + + align:start position:0% +cell +phone if you had to transmit enough + + align:start position:0% +phone if you had to transmit enough + + + align:start position:0% +phone if you had to transmit enough +power to in the worst case do the + + align:start position:0% +power to in the worst case do the + + + align:start position:0% +power to in the worst case do the +Peaks you would on average be + + align:start position:0% +Peaks you would on average be + + + align:start position:0% +Peaks you would on average be +transmitting power at a thousand times + + align:start position:0% +transmitting power at a thousand times + + + align:start position:0% +transmitting power at a thousand times +the rate that you would necessarily have + + align:start position:0% +the rate that you would necessarily have + + + align:start position:0% +the rate that you would necessarily have +to so that's okay for broadcast so for + + align:start position:0% +to so that's okay for broadcast so for + + + align:start position:0% +to so that's okay for broadcast so for +example WBZ broadcast radio WBZ uses a + + align:start position:0% +example WBZ broadcast radio WBZ uses a + + + align:start position:0% +example WBZ broadcast radio WBZ uses a +50 kilowatt transmitter 50 kilowatts is + + align:start position:0% +50 kilowatt transmitter 50 kilowatts is + + + align:start position:0% +50 kilowatt transmitter 50 kilowatts is +the amount of power that would otherwise + + align:start position:0% +the amount of power that would otherwise + + + align:start position:0% +the amount of power that would otherwise +be sufficient to generate 500 100 W + + align:start position:0% +be sufficient to generate 500 100 W + + + align:start position:0% +be sufficient to generate 500 100 W +light + + align:start position:0% +light + + + align:start position:0% +light +bulbs okay + + align:start position:0% +bulbs okay + + + align:start position:0% +bulbs okay +that's a fair amount of power right + + align:start position:0% +that's a fair amount of power right + + + align:start position:0% +that's a fair amount of power right +imagine the heat that comes off 500 100 + + align:start position:0% +imagine the heat that comes off 500 100 + + + align:start position:0% +imagine the heat that comes off 500 100 +watt light bulbs that's how much power + + align:start position:0% +watt light bulbs that's how much power + + + align:start position:0% +watt light bulbs that's how much power +is being radiated by the + + align:start position:0% +is being radiated by the + + + align:start position:0% +is being radiated by the +antenna for + + align:start position:0% +antenna for + + + align:start position:0% +antenna for +WBZ that power is not necessary to + + align:start position:0% +WBZ that power is not necessary to + + + align:start position:0% +WBZ that power is not necessary to +transmit the average message it's + + align:start position:0% +transmit the average message it's + + + align:start position:0% +transmit the average message it's +necessary to transmit the peak + + align:start position:0% +necessary to transmit the peak + + + align:start position:0% +necessary to transmit the peak +message you can imagine how long your + + align:start position:0% +message you can imagine how long your + + + align:start position:0% +message you can imagine how long your +cell phone battery would last if you + + align:start position:0% +cell phone battery would last if you + + + align:start position:0% +cell phone battery would last if you +were transmitting 50 kilow right it + + align:start position:0% +were transmitting 50 kilow right it + + + align:start position:0% +were transmitting 50 kilow right it +doesn't work right so that's a that's + + align:start position:0% +doesn't work right so that's a that's + + + align:start position:0% +doesn't work right so that's a that's +how the uh broadcast radio takes + + align:start position:0% +how the uh broadcast radio takes + + + align:start position:0% +how the uh broadcast radio takes +advantage of broadcast it makes no sense + + align:start position:0% +advantage of broadcast it makes no sense + + + align:start position:0% +advantage of broadcast it makes no sense +to use this coding scheme for a + + align:start position:0% +to use this coding scheme for a + + + align:start position:0% +to use this coding scheme for a +point-to-point + + align:start position:0% +point-to-point + + + align:start position:0% +point-to-point +system it's fine if what you're trying + + align:start position:0% +system it's fine if what you're trying + + + align:start position:0% +system it's fine if what you're trying +to do is have one transmitter WBZ that + + align:start position:0% +to do is have one transmitter WBZ that + + + align:start position:0% +to do is have one transmitter WBZ that +Services a million listeners that's + + align:start position:0% +Services a million listeners that's + + + align:start position:0% +Services a million listeners that's +fine okay problem with this scheme for + + align:start position:0% +fine okay problem with this scheme for + + + align:start position:0% +fine okay problem with this scheme for +decoding is it still doesn't separate + + align:start position:0% +decoding is it still doesn't separate + + + align:start position:0% +decoding is it still doesn't separate +different channels and the way to fix + + align:start position:0% +different channels and the way to fix + + + align:start position:0% +different channels and the way to fix +that was uh develop by Edward Armstrong + + align:start position:0% +that was uh develop by Edward Armstrong + + + align:start position:0% +that was uh develop by Edward Armstrong +so sof was kind of the Visionary he had + + align:start position:0% +so sof was kind of the Visionary he had + + + align:start position:0% +so sof was kind of the Visionary he had +the idea for broadcast radio he's the + + align:start position:0% +the idea for broadcast radio he's the + + + align:start position:0% +the idea for broadcast radio he's the +the the uh entrepreneurial type who + + align:start position:0% +the the uh entrepreneurial type who + + + align:start position:0% +the the uh entrepreneurial type who +thought of how to do this Armstrong was + + align:start position:0% +thought of how to do this Armstrong was + + + align:start position:0% +thought of how to do this Armstrong was +the technical genius he knew how to do + + align:start position:0% +the technical genius he knew how to do + + + align:start position:0% +the technical genius he knew how to do +it so Armstrong's idea here which we + + align:start position:0% +it so Armstrong's idea here which we + + + align:start position:0% +it so Armstrong's idea here which we +call + + align:start position:0% +call + + + align:start position:0% +call +superod was let's make the signal look + + align:start position:0% +superod was let's make the signal look + + + align:start position:0% +superod was let's make the signal look +like it always come from comes from + + align:start position:0% +like it always come from comes from + + + align:start position:0% +like it always come from comes from +Omega I regardless of what channel it + + align:start position:0% +Omega I regardless of what channel it + + + align:start position:0% +Omega I regardless of what channel it +comes + + align:start position:0% +comes + + + align:start position:0% +comes +from so Omega I the intermediate + + align:start position:0% +from so Omega I the intermediate + + + align:start position:0% +from so Omega I the intermediate +frequency will always take Whatever + + align:start position:0% +frequency will always take Whatever + + + align:start position:0% +frequency will always take Whatever +frequency you're interested in and turn + + align:start position:0% +frequency you're interested in and turn + + + align:start position:0% +frequency you're interested in and turn +it into Omega I and we'll do that by + + align:start position:0% +it into Omega I and we'll do that by + + + align:start position:0% +it into Omega I and we'll do that by +just + + align:start position:0% +just + + + align:start position:0% +just +modulating and the cleverness had to do + + align:start position:0% +modulating and the cleverness had to do + + + align:start position:0% +modulating and the cleverness had to do +with with with a lot of technical + + align:start position:0% +with with with a lot of technical + + + align:start position:0% +with with with a lot of technical +details he worked out a scheme where + + align:start position:0% +details he worked out a scheme where + + + align:start position:0% +details he worked out a scheme where +this modulation was very easy the cut + + align:start position:0% +this modulation was very easy the cut + + + align:start position:0% +this modulation was very easy the cut +off the side bands on the band pass + + align:start position:0% +off the side bands on the band pass + + + align:start position:0% +off the side bands on the band pass +filters didn't have to be very uh steep + + align:start position:0% +filters didn't have to be very uh steep + + + align:start position:0% +filters didn't have to be very uh steep +which made them easy to + + align:start position:0% +which made them easy to + + + align:start position:0% +which made them easy to +implement the sharp bam pass filters + + align:start position:0% +implement the sharp bam pass filters + + + align:start position:0% +implement the sharp bam pass filters +were all at that one intermediate + + align:start position:0% +were all at that one intermediate + + + align:start position:0% +were all at that one intermediate +frequency so he had to generate one very + + align:start position:0% +frequency so he had to generate one very + + + align:start position:0% +frequency so he had to generate one very +sharp band pass filter but that same + + align:start position:0% +sharp band pass filter but that same + + + align:start position:0% +sharp band pass filter but that same +sharp bandwidth uh sharp uh bandpass + + align:start position:0% +sharp bandwidth uh sharp uh bandpass + + + align:start position:0% +sharp bandwidth uh sharp uh bandpass +filter then be used for all the + + align:start position:0% +filter then be used for all the + + + align:start position:0% +filter then be used for all the +different + + align:start position:0% +different + + + align:start position:0% +different +channels so uh the idea then was use a + + align:start position:0% +channels so uh the idea then was use a + + + align:start position:0% +channels so uh the idea then was use a +coarse tunable filter to map the + + align:start position:0% +coarse tunable filter to map the + + + align:start position:0% +coarse tunable filter to map the +frequency of interest to Omega + + align:start position:0% +frequency of interest to Omega + + + align:start position:0% +frequency of interest to Omega +I put that through a very sharp filter + + align:start position:0% +I put that through a very sharp filter + + + align:start position:0% +I put that through a very sharp filter +of which there is exactly one in + + align:start position:0% +of which there is exactly one in + + + align:start position:0% +of which there is exactly one in +receiver and then use this uh decoding + + align:start position:0% +receiver and then use this uh decoding + + + align:start position:0% +receiver and then use this uh decoding +scheme + + align:start position:0% +scheme + + + align:start position:0% +scheme +um to tr to uh + + align:start position:0% +um to tr to uh + + + align:start position:0% +um to tr to uh +demodulate the uh carrier + + align:start position:0% +demodulate the uh carrier + + + align:start position:0% +demodulate the uh carrier +wi okay that's how they did it we would + + align:start position:0% +wi okay that's how they did it we would + + + align:start position:0% +wi okay that's how they did it we would +never do it that + + align:start position:0% +never do it that + + + align:start position:0% +never do it that +way right that's part of the theme of + + align:start position:0% +way right that's part of the theme of + + + align:start position:0% +way right that's part of the theme of +the course we we are interested in + + align:start position:0% +the course we we are interested in + + + align:start position:0% +the course we we are interested in +schemes that let us map continuous time + + align:start position:0% +schemes that let us map continuous time + + + align:start position:0% +schemes that let us map continuous time +to discrete time that sort of thing so + + align:start position:0% +to discrete time that sort of thing so + + + align:start position:0% +to discrete time that sort of thing so +one way we might do it is Implement a + + align:start position:0% +one way we might do it is Implement a + + + align:start position:0% +one way we might do it is Implement a +radio digitally okay so the idea would + + align:start position:0% +radio digitally okay so the idea would + + + align:start position:0% +radio digitally okay so the idea would +be what if you took the antenna put it + + align:start position:0% +be what if you took the antenna put it + + + align:start position:0% +be what if you took the antenna put it +through a + + align:start position:0% +through a + + + align:start position:0% +through a +sampler turn the radio signal which + + align:start position:0% +sampler turn the radio signal which + + + align:start position:0% +sampler turn the radio signal which +contains gazillion number of bands for + + align:start position:0% +contains gazillion number of bands for + + + align:start position:0% +contains gazillion number of bands for +for commercial radio there's 100 + + align:start position:0% +for commercial radio there's 100 + + + align:start position:0% +for commercial radio there's 100 +channels in the frequency band 500 to + + align:start position:0% +channels in the frequency band 500 to + + + align:start position:0% +channels in the frequency band 500 to + + align:start position:0% + + + align:start position:0% +khz but just take the whole uh signal + + align:start position:0% +khz but just take the whole uh signal + + + align:start position:0% +khz but just take the whole uh signal +off the antenna turn it into a bunch of + + align:start position:0% +off the antenna turn it into a bunch of + + + align:start position:0% +off the antenna turn it into a bunch of +bits run that through some digital logic + + align:start position:0% +bits run that through some digital logic + + + align:start position:0% +bits run that through some digital logic +that does by Magic picks out the one + + align:start position:0% +that does by Magic picks out the one + + + align:start position:0% +that does by Magic picks out the one +that you're interested in generates a + + align:start position:0% +that you're interested in generates a + + + align:start position:0% +that you're interested in generates a +new stream of bits yd from which you can + + align:start position:0% +new stream of bits yd from which you can + + + align:start position:0% +new stream of bits yd from which you can +do band limited reconstruction so this + + align:start position:0% +do band limited reconstruction so this + + + align:start position:0% +do band limited reconstruction so this +is you know the last two lectures how do + + align:start position:0% +is you know the last two lectures how do + + + align:start position:0% +is you know the last two lectures how do +you do this how you do this now all we + + align:start position:0% +you do this how you do this now all we + + + align:start position:0% +you do this how you do this now all we +do is we put a particular algorithm in + + align:start position:0% +do is we put a particular algorithm in + + + align:start position:0% +do is we put a particular algorithm in +there and we've got a radio that's the + + align:start position:0% +there and we've got a radio that's the + + + align:start position:0% +there and we've got a radio that's the +idea it seems it this is uh oh so the + + align:start position:0% +idea it seems it this is uh oh so the + + + align:start position:0% +idea it seems it this is uh oh so the +key to being able to that is whether or + + align:start position:0% +key to being able to that is whether or + + + align:start position:0% +key to being able to that is whether or +not you can build that + + align:start position:0% +not you can build that + + + align:start position:0% +not you can build that +sampler so what what would be the + + align:start position:0% +sampler so what what would be the + + + align:start position:0% +sampler so what what would be the +required sampling + + align:start position:0% +required sampling + + + align:start position:0% +required sampling +time in order to make a digital + + align:start position:0% +time in order to make a digital + + + align:start position:0% +time in order to make a digital +radio and since I'm running out of time + + align:start position:0% +radio and since I'm running out of time + + + align:start position:0% +radio and since I'm running out of time +uh I I'll just tell you that the + + align:start position:0% +uh I I'll just tell you that the + + + align:start position:0% +uh I I'll just tell you that the +important thing it's sampling it's what + + align:start position:0% +important thing it's sampling it's what + + + align:start position:0% +important thing it's sampling it's what +we did last time the answer is uh you + + align:start position:0% +we did last time the answer is uh you + + + align:start position:0% +we did last time the answer is uh you +need um T so that the sampling frequency + + align:start position:0% +need um T so that the sampling frequency + + + align:start position:0% +need um T so that the sampling frequency +is at least twice the maximum frequency + + align:start position:0% +is at least twice the maximum frequency + + + align:start position:0% +is at least twice the maximum frequency +of the thing that you're trying to + + align:start position:0% +of the thing that you're trying to + + + align:start position:0% +of the thing that you're trying to +code so the the biggest frequency here + + align:start position:0% +code so the the biggest frequency here + + + align:start position:0% +code so the the biggest frequency here +is600 uh + + align:start position:0% +is600 uh + + + align:start position:0% +is600 uh +KZ you need to sample that with Omega + + align:start position:0% +KZ you need to sample that with Omega + + + align:start position:0% +KZ you need to sample that with Omega +sampling more than twice that + + align:start position:0% +sampling more than twice that + + + align:start position:0% +sampling more than twice that +frequency so bigger than 2 pi 1600 khz + + align:start position:0% +frequency so bigger than 2 pi 1600 khz + + + align:start position:0% +frequency so bigger than 2 pi 1600 khz +and if you work that out that leaves a + + align:start position:0% +and if you work that out that leaves a + + + align:start position:0% +and if you work that out that leaves a +sampling time of about a third of a + + align:start position:0% +sampling time of about a third of a + + + align:start position:0% +sampling time of about a third of a +microsc and the point is that that's + + align:start position:0% +microsc and the point is that that's + + + align:start position:0% +microsc and the point is that that's +easy to do these days that's the kind of + + align:start position:0% +easy to do these days that's the kind of + + + align:start position:0% +easy to do these days that's the kind of +part that you get from Digi key for + + align:start position:0% +part that you get from Digi key for + + + align:start position:0% +part that you get from Digi key for +$2 so that's easy so the only thing that + + align:start position:0% +$2 so that's easy so the only thing that + + + align:start position:0% +$2 so that's easy so the only thing that +you need to do is worry about well then + + align:start position:0% +you need to do is worry about well then + + + align:start position:0% +you need to do is worry about well then +how much computation is + + align:start position:0% +how much computation is + + + align:start position:0% +how much computation is +there and that also turns out to be easy + + align:start position:0% +there and that also turns out to be easy + + + align:start position:0% +there and that also turns out to be easy +the principal thing you need to do is + + align:start position:0% +the principal thing you need to do is + + + align:start position:0% +the principal thing you need to do is +make a band pass + + align:start position:0% + + + + align:start position:0% + +filter the question is how would you + + align:start position:0% +filter the question is how would you + + + align:start position:0% +filter the question is how would you +make a bandpass + + align:start position:0% +make a bandpass + + + align:start position:0% +make a bandpass +filter and here are three possible + + align:start position:0% +filter and here are three possible + + + align:start position:0% +filter and here are three possible +systems for making a band pass filter + + align:start position:0% +systems for making a band pass filter + + + align:start position:0% +systems for making a band pass filter +should I take my my digitized antenna + + align:start position:0% +should I take my my digitized antenna + + + align:start position:0% +should I take my my digitized antenna +signal modulate low pass + + align:start position:0% +signal modulate low pass + + + align:start position:0% +signal modulate low pass +modulate or modulate low pass modulate + + align:start position:0% +modulate or modulate low pass modulate + + + align:start position:0% +modulate or modulate low pass modulate +modulate low pass modulate cosine s + + align:start position:0% +modulate low pass modulate cosine s + + + align:start position:0% +modulate low pass modulate cosine s +cosine + + align:start position:0% +cosine + + + align:start position:0% +cosine +s or put it through a filter that looks + + align:start position:0% +s or put it through a filter that looks + + + align:start position:0% +s or put it through a filter that looks +just like that unit sample response + + align:start position:0% +just like that unit sample response + + + align:start position:0% +just like that unit sample response +except that it's multiplied by Co Omega + + align:start position:0% +except that it's multiplied by Co Omega + + + align:start position:0% +except that it's multiplied by Co Omega +CTN + + align:start position:0% + + + + align:start position:0% + +some number of those + + align:start position:0% +some number of those + + + align:start position:0% +some number of those +work and I'll leave it for you to figure + + align:start position:0% +work and I'll leave it for you to figure + + + align:start position:0% +work and I'll leave it for you to figure +out which of those + + align:start position:0% +out which of those + + + align:start position:0% +out which of those +work okay good to see you have a good + + align:start position:0% +work okay good to see you have a good + + + align:start position:0% +work okay good to see you have a good +day \ No newline at end of file diff --git a/Ob9xGBPvr_s.txt b/Ob9xGBPvr_s.txt new file mode 100644 index 0000000000000000000000000000000000000000..f464539ce6d95cc9816e7c00f8cf1cb246a19292 --- /dev/null +++ b/Ob9xGBPvr_s.txt @@ -0,0 +1,4007 @@ +The following +content is provided + +under a Creative +Commons license. + +Your support will help MIT +OpenCourseWare continue + +to offer high quality +educational resources for free. + +To make a donation or +view additional materials + +from hundreds of MIT courses, +visit MIT OpenCourseWare + +at ocw.mit.edu. + +PROFESSOR: So good +afternoon, once again. + +And welcome back to +Computational Systems Biology, + +lecture number seven. + +And today we're going +to put to good use + +two things that we have learned. + +We've learned how to align high +throughput reads to genomes. + +And we've learned how to take +a collection of high throughput + +reads and assemble a genome. + +And today we're going to +delve into the mysteries + +of transcriptional regulation. + +And so what I'd like to +discuss with you today + +is a very important +set of techniques + +that allows us to +elucidate exactly how genes + +are regulated. + +It's probably the most +important technique + +for allowing us to +get at that question. + +And I'm sure many of you +are familiar with the idea + +of transcriptional +regulators, which + +are proteins that bind in +a sequence specific way + +to the genome and act +as molecular switches. + +And we'll return to +some aspects of these + +when we talk about +proteomics later in the term. + +But suffice to +say, these proteins + +have domains that interact +in a sequence specific way + +with the DNA bases in one +of the grooves of DNA. + +They also typically +contain a domain + +which is an activation +domain or repression + +domain that interacts +with other proteins that + +can cause the genome to fold up. + +And it can also help recruit +the RNA polymerase holoenzyme + +to actually turn on +a gene transcription. + +So here we have a +figure of a collection + +of Pit1 molecules +interacting with the genome. + +And of course, there are many +flavors of genomic regulators. + +It's estimated that humans have +about 2,000 different proteins + +that act as these molecular +switches, some as activators, + +some as repressors. + +And we're going to be +talking about, fundamentally, + +today the idea of how +these molecules interact + +with the genome and +control gene expression + +through the analysis +of where they actually + +interact with +specific genome loci. + +So if we were to draw a +picture of how we understand + +gene regulation in cartoon +form, if we have a gene here + +with the transcription +start site + +and we can imagine RNA +molecules being produced off + +of this genomic +template, we know + +that there are non-coding +regions of a gene that + +permit for the binding +of these regulators. + +And my definition +of a gene is all + +of the DNA that's required to +make a specific transcriptive + +protein. + +So that includes not +only the coding parts + +of the gene but the non-coding, +regulatory parts as well. + +So we can imagine +out here that there + +are a collection of +regulators, perhaps just + +one, that bind to a sequence +that in turn activate + +this gene, producing the RNA +transcript, which then in turn + +this turned into +another protein. + +This protein may +undergo some sort + +of post-translational +modification + +by signaling pathway or other +mechanism that activates it. + +So regulators need +to be activated + +before they could +bind and some do not. + +And this activated regular +combine to get another gene + +and cause another +RNA to be expressed. + +And it may be, in +the second context, + +that we need two +different proteins to bind + +to activate the gene. + +And so during the +course of the term, + +we're going to be talking +about many aspects + +of these regulatory networks, +including things like what + +the regulatory code +of a genome is, + +that is where these +binding sites are + +and how they're occupied. + +And we'll return to that +later on in today's lecture. + +We'll talk about the dynamics of +binding of proteins, including + +how concentration +[? they ?] dependent are. + +And we'll talk about +combinatorial control, + +whether or not, +for example, both + +of these have to be +present or just one of them + +needs to be present for +a gene to be transcribed, + +and how you can use these +regulatory sequences + +to implement very complex +computational functions. + +But suffice to say, the +most important thing + +that we have to identify +is the programming + +that underlies the +genome, which includes + +these regulatory sequences +and exactly how they're + +occupied by regulatory proteins. + +Ideally what we would +like to be able to do + +is to do a single experiment +that elucidated all + +of the regulatory +sites in the genome + +and which ones were +occupied by which proteins. + +But presently, that's +technically not possible. + +So we'll begin today +with a technique that + +allows us to consider +one protein at a time + +and identify where it +occupies the genome. + +Now there are other +kinds of proteins + +that we can identify in terms +of where they are associated + +with the genome that are not +transcriptional regulators, per + +se. + +For example, we all +know that chromatin + +is organized on spools +called nucleosomes. + +These nucleosomes are composed +of eight different histones + +that have tails +on them, and there + +can be covalent marks +put on these tails. + +We'll return to this later on +when we talk about epigenetics. + +But I did want to mention today +that it's possible to identify + +where there are histones +with specific barks that + +are present in the +genome and what + +genome sequences they +are associated with. + +So we can look at sequence +specific regulators. + +We could look at a more +general epigenetic marks, + +all using the same technology. + +And this slide simply +recapitulates what we just + +talked about over here on the +left-hand side of the board. + +But we want to +know basically what + +and where, in terms of +these genomic regulators, + +what they are and where +they are in the genome. + +And today we're going to assume +a fairly simple model, which + +is that regulars that are +proximal to a gene, most + +probably regulated. + +Although we know in +practice, actually, it + +appears that roughly one +third of the regulators that + +are proximal to a gene actually +skip it and regulate a gene + +further down the genome. + +It's not really +understood very well + +how the genome +folds in three space + +to allow these transit +regulatory interactions + +to occur. + +But I'll just point out to +you that the simplistic model + +that proximal binding +regulates proximal genes + +doesn't always hold, +especially when + +we get into mammals and +other higher organisms. + +And as I mentioned, +another aspect of this + +is that certain +proteins may need + +to be modified to become +active, and thus there + +are signaling pathways. + +You can imagine signaling +pathways responding + +to environmental stimuli +outside of cells. + +These signaling +pathways can interact + +with transcriptional +activators and modify + +what targets they +seek in the genome. + +So these sorts of +regulatory networks + +will be talked +about specifically + +in a separate lecture +later in the term, + +but they're +extraordinarily important. + +And a foundational +aspect of them + +is putting together +the wiring diagram. + +And the wiring diagram +has to do with where + +the regulators occupy +the genome and what + +genes those regulators regulate. + +And in order to do +that, we're going + +to utilize a +technique today called + +ChIP-seq, which stands for +chromatin immunoprecipitation + +followed by sequencing. + +And we can now reliably +identify where regulars bind + +to the genome within +roughly 10 base pairs. + +So the spatial +resolution has gotten + +exceptionally good with high +throughput sequencing, as we'll + +see, which really is a +fantastic era to be in now, + +because this really +wasn't possible 5 + +or even 10 years ago. + +And so we now have +the tools to be + +able to take apart the +regulatory occupancy + +of the genome and +discern exactly + +where these proteins +are binding. + +The way that this is done, +as I'll describe the protocol + +to you, in general, and then +I'm going to pause for a second + +and see if anybody has any +questions about the specifics. + +But the essential idea is that +you have a collection of cells. + +Typically you need +a lot of cells. + +We're talking 10 million cells. + +So for certain +kinds of marks, you + +can get down below a million +or even to 100,000 cells. + +But to get robust signals, you +need a lot of cells at present. + +And all these cells obviously +have chromosomes inside of them + +with proteins that +are occupying them. + +And the essential idea is that +you take a flash photography + +picture of the cell +while it's alive. + +You add a cross linking agent, +and that cross links proteins + +creates bonds +between the proteins + +and the genome, the DNA, where +those proteins are sitting. + +And so you then isolate +the chromatin material, + +and you wind up with pieces +of DNA with proteins occupying + +them, all the proteins. + +So not just some of the +proteins, but all the proteins + +are non-selectively +cross-linked to the genome. + +You then can take this +extract and fragment it. + +Typically you fragment +it by using sonication, + +which is mechanical energy, +which causes the DNA + +to break at random locations. + +There are more modern +techniques that we'll + +touch on at the end +of today's lecture + +where you could enzymatically +digest these fragments right + +down to where the protein is. + +But suffice to say, you get +small fragments, which you then + +can immunopurify +with an antibody + +to a protein of interest. + +So one condition of using +this technology is either A, + +you have a good +antibody to a protein + +that you care about +as regulatory, or B, + +you have tagged +this protein such + +that it has a flag tag, myc +tag, or some other epitope + +tag on it which allows +you to use an antibody + +or other purification +methodology + +for that specific tag. + +So either you have +a good antibody + +or you have a tag +on the protein. + +One problem with +tags on proteins + +is that they can render +the proteins nonfunctional. + +If they're nonfunctional, +then, of course, + +they're not going to bind +where they should bind. + +And one has to be +careful about this, + +because if you +introduce a tag and you + +have a couple good copies of +the protein that are untagged + +and one copy that +is tagged, it's + +hard to tell whether or not +the tagged version is actually + +doing what you think it does, +and one has to be careful. + +But suffice to say, +assuming that you + +have some way of +immunopurifying this protein, + +you can then use the +antibodies to simply purify + +those fragments that have +the protein of interest. + +After you've purified +the protein of interest, + +you can reverse +the cross linking, + +have a collection of +fragments which you then + +sequence using a high throughput +sequencing instrument. + +Now recall that, in the +usually applied protocol, + +the fragmentation is a random. + +So you're going to be sequencing +both ends of these molecules. + +For each one, you probably +only sequence one end. + +You're going to sequence an +end of these molecules which + +gives you a sequence tag that is +near where the event occurred, + +but not exactly at it. + +And we're going to +take those tags, + +and if we have our +genome-- here represented + +as this short, horizontal chalk +line-- we'll take our reads, + +and we will align +them to the genome, + +and try and discern +from those aligned + +reads where the original +proteins were binding. + +Now our job is to do the best +possible alignment or discovery + +of where the proteins are +binding, given this evidence. + +So we have a +collection of evidence + +exhibited by the read sequences. + +The other thing +that we will do is + +we will take the original +population of molecules, + +and we will sequence +them as well, + +sometimes called the whole cell +extract sequence, as a control. + +And we'll see why we need this +control a little bit later on. + +But this is going to be +a purified so-called IP + +for immunoprecipitate +fraction, which we'll sequence. + +And this will be the whole +cell extract, which should not + +be enriched for any +particular protein. + +Now before I go on, I'd be +happy to entertain any questions + +about the details +of this protocol, + +because it's really important +that you feel comfortable + +with it before we talk about +the computational analysis + +of the output. + +So if anybody has +any questions, now + +would be a great time to ask. + +Yes. + +AUDIENCE: I have more of +a scientific question. + +This assumes that we know +a transcriptioned factor. + +Are there are ways, methods +to figure out transcription + +factors so that you can design +antibodies to bind to it? + +PROFESSOR: So the +question is, this + +assumes that we know the +regulators that we're + +interested in ahead of time. + +And is there a de novo +way of discovering + +heretofore unknown regulators +that are binding to the genome? + +The answer to that +question is sometimes, + +as is usually the case. + +Later in the term, we'll talk +about other methodologies + +for looking at the regulatory +occupancy of the genome that + +don't depend upon +immunopurification, + +in which case we'll get +an understanding of what's + +going on with the genome at +the level of knowing what + +particular sequences are +occupied without knowing what's + +there. + +From the sequence, +sometimes we can + +infer the family of the +protein that is sitting there. + +But in general, the holy grail +of this, which has not really + +fully materialized, +would be as follows, + +which is instead of +purifying with an antibody + +and then sequencing, why not +purify with a nucleic acid + +sequence and then do mass spec, +to actually take the proteins + +off of the DNA, run +them through mass spec, + +and figure out what's there. + +And we and others +have attempted this. + +And at times, you +get good results. + +But mass spec is +improving greatly, + +but it's till a fraught +process with noise. + +And there's a paper just +published in Nature Methods + +late last year on something +called the CRAPome. + +Have you heard of +this paper before? + +It is all the junk you get when +you run mass spec experiments. + +And so when you run a +mass spec experiment, + +you can just take all the +stuff in the CRAPome out of it, + +and it actually helps +you quite a bit. + +That gives you an idea what the +state of the art of mass spec + +is. + +It's a little bit noisy. + +But I think your +question is great. + +I think we need to get there. + +We need to get to +the place where + +we can take portions +of the genome + +and run them through +mass spec and figure out + +what is populating it de novo +without having to know ahead + +of time. + +Any other questions? + +OK. + +Great. + +So the figure on +the slide up there + +also describes the +ChIP-seq protocol. + +And I'll also say +that some people + +believe this would never work. + +They actually thought that +when you did the purification, + +you would just get so +much background sequence + +that when you map +it to the genome, + +you could never discern +any signal whatsoever. + +And so there are lively debates +about this until somebody + +actually made it work, +and then the argument + +was over because it made +everything else completely + +and totally obsolete. + +So it wasn't good to be on the +wrong side of that argument, + +I'll tell you that. + +I wasn't, but all right. + +I was on the right side. + +But suffice to say, here's +a close-up picture of Mr. + +Protein-- Ms. Protein-- and what +happens when there is breakage + +around that site, +followed by sequencing. + +And as you can see, +the little black lines + +connecting between the +protein and the DNA + +is supposed to indicate +contacts sites. + +And you can see the little +yellow arrows are supposed + +to indicate breakage sites of +the DNA that are being caused + +by, in this case, mechanical +breakage through sonication. + +And you get reads from +both strands of the DNA. + +Remember that a sequencing +instrument always + +sequences from five +prime to three prime. + +So you're going to get the +reads on the red strand + +and on the blue +strand, shown here. + +And when we do the +mapping, we know + +which strand they're mapped on. + +And the profile is +shown in the lower plot, + +showing the density of +map reads versus distance + +from where we believe +the protein is sitting. + +And the tag density refers +to tags or sequence tags + +or reads that are aligned using +the methodology we discussed + +two lectures ago to the genome +we assembled last lecture. + +So the characteristic +shape shown in this picture + +is something that is not +the same for all proteins. + +It is something that varies +from protein to protein. + +And thus, one of the +things that we'll + +want to do during our discovery +of where these proteins are + +binding is always learn the +shape of the read distribution + +that will come out of a +particular binding event. + +So just to show you some +actual data, so you'll + +get a feel for what +we're talking about, + +this is actual data from +the Oct4 protein, which + +is an embryonic regulator, +pluripotency factor, + +binding to the mouse genome +around the SOCS2 gene. + +And you can see the two distinct +peaks on the upper track, + +both the plus strand +reads and the minus strand + +reads, shown in blue +and red respectively. + +Each one of the black and +white bars at the top-- + +probably can't be read +from the back of the room-- + +but each one of +those is 1,000 bases, + +to give you some idea about +sort of the scale of the genome + +that we're looking at here. + +You can see the +SOCS2 gene below. + +The exons are the solid bars. + +And then you see the whole +cell extract channel, + +which we talked about earlier. + +And the whole cell +extract channel + +is simply giving us a +background set of reads + +that are nonspecific. + +And so you might have a set of, +say, 10 or 20 million reads, + +something like that, for when +these experiments that you map + +to the genome and get a +picture that looks like this. + +So now our job is to take the +read sets that we see here, + +genome wide, and +figure out every place + +that the Oct4 protein is +binding to the genome. + +Now there are +several ways that we + +could approach this question. + +One way to approach +the question would + +be to simply say, +where are the peaks? + +And so you hear this kind of +exploration often described + +as peak finding. + +Where can you find the peaks? + +And where is the +middle of the peak? + +Now the problem +with this approach + +is that it works just fine +when a peak represents + +a single binding event. + +So imagine that these +two fingers here + +are binding events, and they're +fairly far apart of the genome. + +Now as they come closer and +closer and closer together, + +what will happen is that, +instead of having two peaks, + +we're going to wind up +having one broad peak. + +And thus, there's a +lot of biology present + +in this kind of binding +of the same protein + +proximal to itself. + +So we need to be able to take +these sorts of events that + +occur underneath a single +enrichment, or single peak, + +into two separate +binding events. + +And this is shown in the +next couple of slides, + +right where we look at +what we would expect + +from a single event, in terms +of a read enrichment profile + +once it's aligned to the genome. + +And we think about a +possibility that there + +are two events, here +shown in indiscernible + +gray and blue and red. + +And we note that +each one of these + +will have its own +specific profile. + +And then you can consider +them to be added together + +to get the peak that we observe. + +Now one of the reasons this +additive property works + +is that, remember, we're +working with a large population + +of cells, and regulators +don't always occupy a site. + +And thus, what we're looking +at in terms of the reads + +are the sum of all of the +evidence from all of the cells. + +And so even though the proteins +are close to one another, + +we often can find +an additive effect + +between that proximal binding. + +So how can we handle this? + +Well, what we're +going to do is we're + +going to do two key +algorithmic things. + +We're going to model the spatial +distribution of the reads that + +come out of a specific event, +as I suggested earlier. + +And we're going to keep +that model up to date. + +That is, we can learn that model +by first running our method + +using a common +distribution of reads, + +identify a bunch +of events that we + +think are bindings of a single +protein, take those events + +and use them to build +a better model of what + +the redistribution looks like, +and then run the algorithm + +again. + +And with the better +distribution, + +we can do a much better +job at resolving events out + +of multiple events +out of single peaks. + +And the next thing +we're going to do + +is we're going to model the +genome at a single base pair + +level. + +So we're going to consider every +single base as being the center + +point of a protein binding +event, and using that model, + +try and sort through how +we could have observed + +the reads that we +are presented with. + +And first, the spatial +distribution that we build + +is going to look +something like this. + +And we consider a +400 base pair window, + +and we learn the +distribution of reads, + +and we build an actual +empirical distribution. + +We don't fit the +distribution to it, + +but rather we can keep an +exact distribution or histogram + +of what we observe, averaged +over many, many events. + +So when we're fitting things, +we have the best possible + +estimate. + +Yes. + +AUDIENCE: I was just +trying to remember + +to origin of the +[INAUDIBLE] clearly. + +So within the protocol, +are you sequencing + +with the proteins bound +to these fragments? + +PROFESSOR: No. + +See, you can't do that. + +You have to reverse the +cross-linking from the DNA. + +And then there's +a step here which + +we omitted for simplicity, +which is, we amplified the DNA. + +AUDIENCE: So I was +just wondering, + +if there's no protein, why +doesn't the polymerase just + +read through the whole +thing from one side? + +Why is there a peak? + +There seems to be a +loss of signal right + +where the protein is bound. + +PROFESSOR: Well, that depends +upon how long the reads are + +and how hard you fragment. + +And in fact, that can occur. + +But typically, +we're using fairly + +short reads, like +35 base pair reads. + +And we're fragmenting +the DNA to be, + +say, perhaps 200 to +300 base pairs along. + +So we're reading the first 35 +base pairs of the DNA fragment, + +but we're not really +all the way through. + +We could read all the +way through if we wanted, + +but there really wouldn't +be a point to that. + +The thing that +we're observing here + +is where the five prime +end of the readers, where + +the leftmost edge +of the read is. + +So even though it might be +reading all the way through, + +we're just seeing +the left edge of it. + +Does that answer your question? + +AUDIENCE: Yeah. + +PROFESSOR: OK, great. + +Any other questions? + +Yes, at the back. + +AUDIENCE: So to clarify, +this distribution + +that's being shown +up here on both + +the positive and +negative strand-- + +PROFESSOR: Yes. + +AUDIENCE: This is the position +of where the reads started, + +not the count of the number of +times that particular base was + +shown in the sequencing result. + +Is that correct? + +PROFESSOR: Let me +repeat the question. + +What we're observing +in the distribution + +is where the read starts +and not the number of times + +that base shows up in +the sequencing data. + +It is the number of reads +whose five prime position + +start at that base. + +OK So each read +only get one count. + +Does that help? + +OK. + +The other thing that we're +going to do, for simplicity, + +is we're going to assume +that the plus and the minus + +strand distributions +are symmetric. + +So we only learn +one distribution, + +and then we flip it to +do the minus strand. + +And that's shown here, +where we can articulate + +this as this empirical +distribution, + +where the probability or +read given a base position is + +described in terms of the +distance between where we are + +considering the binding +of it may have occurred + +and where the read is. + +So it's important for us to +look at this in some detail + +so you're comfortable with it. + +Here's our genome again. + +And let's assume that +we have a binding + +event at base m +along the genome. + +And we have a read here, +r sub n, at some position. + +The probability +that this read was + +caused by this binding event can +be described as probably a read + +n given the fact that +we're considering + +an event at location m. + +Now of course, it +could be that there + +are other possible locations +that have caused this read. + +And let us suppose +that we model all + +of those positions along +the genome as a vector pi. + +And each element of pi describes +the probability or the strength + +of a binding event +having occurred + +in a particular location. + +So we can now describe the +probability of a read sub n + +given pi is equal +to the summation + +where i equals 1 to big +M, assuming that there + +is 1 to M bases in this +genome, of a p rn given m pi m, + +like this. + +So we are mixing together +here all of the positions + +along the genome to try +and explain this read. + +So the probably of the +read, given this vector + +pi, which describes all +the possible events that + +could have created this +read, is this formulation, + +which considers the +probability of each position + +times the probability that an +event occurred at that position + +subject to the constraint +that all of a pi i's sum to 1. + +So we're just assigning +probability mass + +along the genome from whence all +of the reads originally came. + +So this is considering +a single read, r sub n, + +and where that might +have originated from. + +Yes. + +AUDIENCE: Does the +constraint basically state + +that only one event occurred +in this fragment point? + +PROFESSOR: The question +is, does this constraint + +imply that only +one event occurred? + +No. + +The constraint is +implying that we're + +going to only have one +unit of probability mass + +to assign along the genome which +will generate all of the reads. + +And thus, this vector +describes the contribution + +of each base to the +reads that we observe. + +So let us say +simplistically that it + +might be that there are only +two events in the genome, + +and we had a perfect solution. + +Two points in the +genome, like m1 and m2, + +would have 0.5 as +their values for pi. + +And all the other values +in the genome would be 0. + +We're going to try to make +this as sparse as possible, + +as many zeroes as possible. + +So only at the places in +the genome where protein + +is actually binding +will pi i be nonzero. + +Does that make sense? + +These are great questions. + +Yes. + +And if people could +say their names first, + +that would be great. + +Yes. + +AUDIENCE: Sara. + +Just to clarify, the pi vector +is completely empirical? + +PROFESSOR: This distribution +is completely empirical. + +Yes, that's right, Sara, +completely empirical. + +I'll also say, just so +you know, that there + +are many ways of doing +this kind of discovery, + +as you might imagine. + +The way we're going +to describe today + +was a way that was selected +as part of the ENCODE 3 + +pipeline for the +government's ENCODE project. + +And so what I'm going +to talk about today + +is the methodology that's being +used for the next set of data + +for ENCODE 3 followed +by IDR analysis, which + +is also part of ENCODE 3. + +So what you're +hearing about today + +is a pipeline that's being +used that will be published + +next year as part of +the ENCODE project. + +These papers, this +method's been published. + +But the analysis of +all the Encyclopedia + +of DNA Elements-- which +is what Encode stands + +for-- the third phase of +that is utilizing this. + +OK, any other questions? + +Yes. + +AUDIENCE: Does the shape +of this binding event + +tell you anything about the +topology of the actual protein? + +PROFESSOR: It does, actually. + +And we'll return to that. + +But the shape of this +binding can tell you + +something about the class +of protein, which is still + +an area of active research. + +But also note that +that is a little bit + +confounded by the +fact that when you + +have homotypic +binding, which means + +you have these closely +spaced binding events, + +you get these broader peaks. + +And so there's a lot +of research into what + +the shapes on the genome mean +and what biological function + +of mechanism they might imply. + +Yes. + +AUDIENCE: Can you +explain pi one more time? + +PROFESSOR: Yeah, explain +pi one more time, sure. + +So pi is describing +where there are + +binding events along the genome. + +So for example, if we just had +two binding events, m1 and m2, + +then pi of m1 would be +equal to 0.5, and pi of m2 + +would be equal to 0.5, and +all the other values of pi + +would be 0. + +So we're just describing with pi +where the events are occurring. + +That gives us the +location of the events. + +OK? + +And you'll see in a moment why +we articulated it that way. + +But that's what pi is doing. + +Does that answer your question? + +OK. + +Any other questions? + +Yes. + +AUDIENCE: In cases +when you have two peaks + +really close together, +to a point that there's + +some sort of +[INAUDIBLE] between, + +how do you constrain your pi? + +PROFESSOR: How do +you constrain the pi + +when you have +closely spaced peaks? + +AUDIENCE: Yeah. + +PROFESSOR: Well, you +don't constrain it. + +You actually want-- + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: Well, I'm +going to show you + +some actual examples of +this algorithm running. + +So I'm going to give you an +animation of the algorithm + +running, so you can +actually watch what it does. + +And you'll see, first +it's going to be something + +that isn't too pleasant, +and then we'll fix it. + +But the key thing +here is sparsity. + +What we want to do is +we want to enforce pi + +being as sparse as possible +to explain the data. + +One of the common problems +in any approach to machine + +learning is that, with a +suitably complex model, + +you can model anything, but it's +not necessarily interpretable. + +So what we want to do here is +to make pi as simple as possible + +to be able to explain +the data that we see. + +However, if a single event +cannot explain and observe + +redistribution at a particular +point in the genome, + +we'll need to bring +another event in. + +All right, so that is how to +think about a single read. + +And now we can just +say the probability + +of our entire read set +given pi is quite simple. + +It's simply the product +over all the reads. + +Sorry. + +Like so. + +So this is the probability +of the entire read set. + +So we had this +previously, which is + +the probability +of a single read. + +And we take the product of the +probability for each individual + +read to get the likelihood +of all the reads. + +So now all we need to do to +solve this problem is this. + +We need to say that pi +is equal to the arg max + +pi of P R pi, which gives +us the maximum likelihood + +estimate for pi. + +Now it's easy to +write that down, just + +find the setting for +pi that maximizes + +the likelihood of the observed +reads, and proof, you're done, + +because now you've come up +with a pi that describes where + +the binding events +are along the genome + +at single base pair +solution, assuming + +that pi is modeling +every single base. + +Does everybody see that? + +Any questions about that? + +Yes. + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: n is the +number of reads. + +m is a number of +bases in the genome. + +n is the number of reads. + +AUDIENCE: The +length of pi, right? + +Is that equal to the +number of binding events? + +Or is it equal to just +the number of [INAUDIBLE]? + +PROFESSOR: The length of pi? + +AUDIENCE: Yeah. + +PROFESSOR: It's the number +of bases in the genome, + +and hopefully the +number of bindings + +is much, much, much +smaller than that. + +Typical number of binding +events is 5 to 30,000 + +across a genome that has +3 billion bases, something + +like that. + +So it's much, much smaller. + +OK? + +So this is what we +would like to solve. + +And another way to look +at this model, which + +it may be somewhat +more confusing, + +is as follows, which is that +we have these events spread + +along the genome. + +And we have the reads +shown on the lower line. + +And the events are +generating the reads. + +So this is called +a generative model, + +because the derivation +of the likelihood + +directly follows from, if we +knew where the events were, + +we could exactly +come up with the best + +solution for the +assignment of pi, + +and thus for the likelihood. + +So this is what we have +on the board over here. + +But we can solve this directly. + +Yes. + +Question in the back. + +AUDIENCE: Hi. + +My name is Eric. + +I have a little question. + +What is the definition +of GPS here? + +PROFESSOR: Oh, sorry. + +Yeah, GPS is the name +of this algorithm. + +I told it to an editor +and they hated it. + +But at any rate, it's called +the genome positioning system. + +[LAUGHTER] + +Yeah, so you don't like +it either, right, Eric? + +Oh, well. + +But yes, it locates proteins +on the genome, right? + +Yeah. + +Good question. + +So this is going to be, I +think, our first introduction + +to the EM algorithm +as a way of solving + +complex problems like this. + +And here is the +insight we're going + +to use to solve +this problem, which + +is that imagine I +do the function g. + +So g is going to be +this function that + +tells us what reads +came from which events + +and where those events +are in the genome. + +So if you knew g +exactly, this would + +be a really trivial +problem to solve. + +It would tell you, for +every single read, which + +particular binding +event caused it. + +And if we knew that, +it would be great, + +because then we could +say something like this. + +We could say, well, we knew g. + +Then the number of reeds created +by a binding event at location + +m would simply be-- it's not a +very good summation sign here-- + +we would sum over all the reads +and count up the number of them + +where read n was caused +by an event at location m. + +And we just summed +up this number. + +We'd have the number +of reads caused + +by an event at location m. + +Is everybody cool with that? + +No. + +Do you see the +definition of there of g + +on the overhead projector? + +So every time a read +n comes from event m, + +that function is going +to be equal to 1. + +So we just count the +number of times it's 1. + +For a given location +m, we find out + +how many reads came from +that event-- could be 5, + +could be 10, could be 100. + +We don't know exactly +how many were generated + +by that particular +event, but there's + +going to be some number. + +And we have 10 million reads, +and we have 100,000 events, + +we're going to get +about 100 reads + +per event, something like that. + +You can give that kind +of order of magnitude. + +Everybody OK? + +Any questions about +the details of this? + +Because the next step is going +to be causing leaps of faith, + +so I want to make sure that +everybody's on firm ground + +before we take +the leap together. + +Yes. + +AUDIENCE: So you are +in forced sparsity yet? + +PROFESSOR: I'm not in +forced sparsity yet. + +You like sparsity. + +You're going to keep +me to that, right? + +So later on, you'll hold +me to it, all right? + +That's your job. + +What's your name? + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: OK. + +That's your job, all right? + +Mr. Sparsity. + +I like that. + +He's been sparse. + +I like it. + +So if this is the +number of reads assigned + +to a particular +location, then we + +know that pi sub +m will simply be + +n sub m over the summation +of all of the reads assigned + +to all of the events. + +And some of these +are going to be zero. + +A lot of them will be zero. + +So here, I don't know this +assignment of reads to events. + +It's latent. + +It's something I have +invented which I do not know. + +But if I did know it, I'd be +able to compute pi directly, + +like so, because I'd +be able to figure out + +for each location on the genome +how many reads were there. + +And that's how much +responsibility that location + +had for generating +all of the reads. + +Is everybody with me so far? + +Any questions at all? + +OK. + +So remember, this is latent. + +We don't know what it +is, but if we did know, + +we'd be in great shape. + +So our job now is to estimate g. + +And if we could estimate +g, we can estimate pi. + +And once we get a +better estimate for pi, + +I'd like to suggest +to you we can + +get a better estimate for g. + +And we can go between +these two steps. + +And so that's what the +expectation, maximization + +algorithm does in the +lower part here, which + +is that the left part is +estimating gamma, which + +is our estimate for g, which is +looking at the number of reads + +that we think are softly +assigned to a location m + +over the total number +of softly assigned + +reads from all locations. + +And that gives the fraction of +a read at n assigned to event m. + +So we are computing +an estimate of g. + +But to compute this +estimate, we have to have pi. + +It's telling us where we +believe that these reads are + +coming from. + +And once we have gamma, +which is an estimate, + +we can compute pi, just in the +same way we computed it here, + +if we knew g. + +So we compute the expectation +of this latent function, which + +we don't know, and +then we maximize + +pi to maximize our likelihood. + +And you can derive +this directly by taking + +the log of that likelihood +probability up there + +and maximizing it. + +But suffice to say, you wind +up with this formulation + +in the EM framework. + +So I can go between these +two different steps-- + +the E step, the M step, +the E step, the M step. + +And each time as +I go through it, + +I get a better and better +approximation for pi, + +until I ultimately get it +within some preset level + +of convergence. + +And then I'm finished. + +I actually can report my pi. + +But before I leave the EM +algorithm, and this formulation + +of it, are there +any questions at all + +about what's going on here? + +Yes, question in the back. + +AUDIENCE: So the solution +to the EM algorithm + +doesn't always [INAUDIBLE]? + +PROFESSOR: It gives +you a solution. + +And it is the optimum solution +given the starting conditions + +that we give it. + +AUDIENCE: But it depends on +the starting conditions, right? + +PROFESSOR: It does depend +on the starting conditions. + +Any other questions? + +Yes, in the back. + +AUDIENCE: Is this +dependent upon you + +having discrete binding events? + +So if you have a protein that +has more diffuse localization + +across the genome, for +example, RNA Pol II, + +would this model break down? + +PROFESSOR: So the +question is, does this + +depend upon you having +discrete binding events? + +What biological assumptions are +we making in this model about + +whether or not a protein is +actually fixed and welded + +to the genome in a +particular location + +or whether or not +it's drifting around? + +And this might be of +particular interest, + +for example, if we're +looking at histones, which + +are known to slide up +and down the genome, + +and we're +immunoprecipitating them. + +What will this give us? + +We are making the +assumption that we're + +dealing with proteins that have +punctate binding properties, + +that actually are +point binding proteins. + +And thus what we're going to +get out of this, as you'll see, + +is going to be a +single location. + +There are other methodologies, +which I won't describe today, + +for essentially deconvolving +the motion of a protein + +on the genome and coming +up with its middle + +or mean position while +allowing it to move. + +But today's +algorithm is designed + +for point binding proteins. + +Good question, OK? + +All right. + +So just to be clear, +what we're going to do + +is we're going to +initialize everything, + +such that we'll begin +by initializing pi + +to be 1 over the +size of the genome. + +And at the very end of this, +the strength of a binding event + +will be simply the number of +reads assigned to that event + +by summing up our estimate of g. + +And the nice thing about this +is that because the number + +of reads assigned to an +event, in some sense, + +is scaled relative to +the total number of reads + +in the experiment, we can +algorithmically take our genome + +and chop it up into +independent pieces + +and process them +all in parallel, + +which is what this +methodology does. + +All right. + +So let's have a +look at what happens + +when we run this algorithm. + +So here we are. + +This is synthetic data. + +I have events planted at +500 and 550 base pairs. + +The x-axis is between +0 and 1,400 base pairs. + +And the y-axis is +pi from 0 to 1. + +So here we go. + +It's running. + +And this is one base +pair resolution. + +And it is still +running-- and stop. + +Well, we get sort of a +fuzzy mess there, don't we? + +And the reason we're +getting a fuzzy mess there + +is that we have got a lot +of reads we've created, + +and there are a lot of +different genome positions + +that are claiming some +responsibility for this, which + +my friend, Mr. Sparsity, +doesn't like, right? + +We need to clean +this up somehow. + +And let's see what +happens when we actually + +look at actual data. + +So here is that original +data I showed you + +for the two Oct4 binding +events next to the SOCS2 gene. + +And I'll run the +algorithm on these data. + +And you can see it +working away here. + +And once again, it's giving +us a spread of events, + +and you can see +it even beginning + +to fill in along where +there's noise in the genome + +and stopped here. + +And it's assigning the +probability mass of pi + +all over the place. + +It is not sparse at all. + +So does anybody +have any suggestions + +for how to fix this? + +We've worked all might. + +We've got our algorithm running. + +We thought it was going +to be totally great. + +When we run it, it gives us +this unfortunate, smeary kind + +of result. + +What could we do? + +Any ideas at all? + +Yes. + +AUDIENCE: Add a prior where +most of the reads are. + +PROFESSOR: Add a prior. + +You saw the word no +prior, a little tip off. + +Yeah, absolutely, good point. + +Add a prior. + +So what we're going +to do is we're + +going to try and add a prior +that's going to prejudice pi + +to be 0 to create sparsity. + +So we like pi being 0. + +So we'll add what's called +a negative Dirichlet prior, + +which looks like this, which is +the probability of pi there is + +proportional to 1 over pi to +the m raised to the alpha power. + +And as pi gets smaller, +that gets much, much bigger. + +And thus, if we add +this prior, which + +happens to be a very +convenient prior to use, + +we can force pi to +be 0 in many cases. + +And when we take that prior +into account and we compute + +the maximum a posteriori +values for pi, + +the update rules +are very similar, + +except that what's +interesting is + +that the rule on the left for +computing our estimate of g + +is identical. + +But on the right, what we do +is we take the number of reads + +that we observe at a +particular location + +and we subtract +alpha from it, which + +was that exponent in our prior. + +And what that simply means is +that if you don't have alpha + +reads, you're history. + +You're going to get eliminated. + +So this is going to do something +called component elimination. + +If you don't have +enough strength, + +you're going to +get zapped to zero. + +Now you don't want to do this +too aggressively early on. + +You want to let things sort +of percolate for a while. + +So what this algorithm does +is it doesn't eliminate + +all of the components that don't +have alpha reads at the outset. + +It lets it run for +a little while. + +But it provides you with a way +of ensuring that components + +get eliminated and set to zero +when they actually don't have + +enough support in the read set. + +So once again, all +we're going to do + +is we're going to add this prior +on pi, which we will wind up + +multiplying times +that top equation. + +We'll get the joint probability +of r and pi in this case, + +and then we're going to maximize +it using this EM adaptation. + +And when we do so, +let me show you + +what happens to our first +example that we had. + +OK, that's much cleaner, right? + +We actually only have +two events popping out + +of this at the right locations. + +All right. + +So that's looking good. + +And the probability is +summed to 1, which we like. + +And then we'll run +this on the Oct4 data. + +And you can see now, +instead of getting + +the mushing around +those locations, what's + +going to happen is that +most of the probability mass + +is going to be absorbed into +just a couple components + +around those binding events. + +Now another way to test this +is to ask whether or not, + +if we looked at what we +believe are closely spaced + +homotypic events, in this case, +for CTCF, with that prior, + +we still can recover +those two events being + +next to each other +in the genome. + +And so if we run this, you +can see it running along here. + +Each one of these iterations, +by the way, is an EM step. + +And there you go. + +And you can see that +even from the sparse data + +you see above-- that's the +actual data being used, + +all those little bars +up there, read counts + +for the five prime ends of +the reads-- we can recover + +the position of +those binding events. + +Question, yes. + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: It depends +upon the number of reads, + +but it's somewhere +around three or four. + +I mean, if you look at the +GPS paper, which I posted, + +it tells you how alpha is set. + +Yes. + +AUDIENCE: Do you use +wholesale extract data + +when you are trying to compute? + +PROFESSOR: Question, do we +use wholesale extract data? + +I told you all how +important it was, + +and I haven't +mentioned it again. + +We're about to get to that, +because that's very important. + +I'm glad you asked +that question. + +Yes. + +AUDIENCE: It looks like, +along the genome coordinates, + +each event is only +one base pare, + +but binding is usually +more than one base pair. + +So is that the center +of the binding? + +PROFESSOR: Yes. + +Well, it's the center of the +read distribution function. + +Whether or not it's the center +of the binding of the protein, + +I really can't tell. + +OK, great. + +And I'll just point out +that a power of this method + +is its ability to take +apart piles of reads + +like this and to these so-called +homotypic binding events, where + +you can see where the motif is. + +And you can see this method will +take apart that pile of reads + +into two independent events, +whereas other popular methods, + +of which there are +many for analyzing + +these type of ChIP-seq +data, don't take apart + +the event into multiple +events, because most of them + +make the assumption +that one pile of reads + +equals one binding event. + +Now back to our question +about wholesale extract. + +What happens if you get to +a part of the genome that + +looks like this? + +We're going to go +back to our Oct4 data. + +And we have our Oct4 IP +track, which is above, + +and then our wholesale +extract tract + +is down there on the bottom. + +What would you say? + +Would you say those are +really Oct4 binding events? + +Or do you think something +else is going on there? + +If so, what might it be? + +Any ideas about +what's going on here? + +Yes. + +AUDIENCE: Regions with a lot +of repeats in the genome? + +PROFESSOR: Regions with +repeats in the genome? + +Yes. + +In fact, you can see repeats +annotated in green right there. + +And as you recall from last time +when we talked about assembly, + +it's very difficult +to actually get + +the number of repeat +elements correct. + +And a consequence of that +is if you underestimate + +the number of repeat +elements in the genome + +and you collapse them, when +you do sequencing of the genome + +and you remap it, you're going +to get regions of the genome + +were a lot of reads pile +up, because they're actually + +coming from many different +places in the genome, + +but they only have +one place to align. + +And these towers of +reads, as they're called, + +can create all +sorts of artifacts. + +So in order to judge the +significant of events, + +what we'll do is a +two-step process. + +First, we will run +our discovery pipeline + +and discover where all the +events are in the IP channel + +without regard to the +wholesale extract channel, + +in this particular case. + +And then we will +filter the events + +and say which of the events +are real in view of the data + +from the wholesale +extract channel. + +And so the way to +represent this is + +what is the likelihood we +would have seen those IP reads + +at random given the +wholesale extract channel? + +So how can we +formulate this problem? + +Well imagine that we +take all of the reads + +that we see in both channels +and we add them together. + +So we get a total +number of reads + +at a particular +location in the genome. + +If, in fact, they were +going to occur at random, + +we'd be doing a coin flip. + +Some reads will go +on the IP channel. + +Some reads will go on the +wholesale extract channel. + +So now we can ask what's the +probability we observed greater + +than a certain number of +reads on the IP channel + +at chance, assuming a +coin flipping model where + +we've added the reads together. + +Another way to view that is +what's the chance that we have + +observed less than +a certain number of + +reads in the wholesale +extract channel + +assuming a coin flipping model? + +And that will give us a p-value +under the null hypothesis + +that, in fact, there +is no binding event + +and simply what's +going on is that we + +have reads being flipped +between the two channels out + +of a pool of the +total number of reads. + +And if we take that +approach, we can formulate it + +as the binomial in +the following way. + +We can compute a p-value for +a given binding event using + +the data from both +the IP channel + +and from the control channel. + +And the way that we do this is +that we look at the number of + +reads assigned to an +event, because we already + +know that number. + +We've computed that number. + +And we take a similar window +around the control channel. + +We count the number +of reads in it + +and ask whether or not the +reads in the IP channel + +is significantly larger enough +than the reads in the control + +channel to reject the null +hypothesis that, in fact, they + +occurred at random. + +So this is the way that +we compute the p-values + +for events. + +So once we've computed +the p-values for events, + +we still have our multiple +hypothesis correction problem, + +which is that if we +have 100,000 events, + +we need to set our p-value's +cut off and appropriate value. + +And I think that +you may have heard + +about this before in recitation. + +But the way that this +is done in this system + +is to use a +Benjamini-Hochberg correction. + +And the essential idea is that +we take all of the p-values + +and we organize them +from smallest to largest. + +And we're going to take +a set of the top events, + +say 1 through 4, and +call them significant. + +And we call them significant +under the constraint + +that p-value sub i is less +than or equal to i over n, + +where n is the total number +of events times alpha, + +which is our desired +false discovery rate. + +So this allows us +in a principled way + +to select the events +that we believe + +are significant up to a false +discovery rate, which might be, + +for example, 0.05 for +something that's typically + +used for a false discovery rate. + +So we've talked about +how to discover events, + +how to judge their +significance individually, + +how to take a ranked list of +events from a given experiment + +and determine which +ones are significant + +up to a desired +false discovery rate. + +The false discovery +means that, let's say, + +that we have 1,000 +events that come out. + +If this false +discovery rate was 0.1, + +we would expect 100 of +them to be false positives. + +So it's the fraction +of positives + +that we detect that we +think are going to be false. + +And we can set that to +be whatever we want. + +Now let's talk about the +analysis of these sort of data. + +There's a question up here. + +Yes. + +AUDIENCE: So this randomness, +does that correct to the fact + +that in your previous slide the +coin isn't necessarily fair? + +PROFESSOR: Oh, the +null hypothesis + +assumed that the coin was fair, +that reads could either occur. + +That in this case, for +example, that the reads were + +either occurring in the control +channel or in the IP channel + +with equal likelihood, assuming +because they were coming + +from the same process, which was +not related to the IP itself. + +They're coming from some +underlying noise process. + +AUDIENCE: So typically +you'd have some fixed number + +of reads, and so in the IP +channel, the bulk of your reads + +was in your peaks. + +Then you would have +fewer in your-- + +PROFESSOR: So the +question is, how do you + +normalize for the +number of reads + +and how they're being spent? + +Because in the IP +channel, you're + +spending the reeds on +IP enriched events. + +In the wholesale +extract channel, + +you're not spending +the reads on those, + +so you have more reads to +go around for bad things, + +so to speak. + +So what this algorithm +does-- which I'm glad + +you brought it up-- is it takes +regions of the genome that + +are event free, and it matches +them up against one another + +and fits a model +against them to be + +able to scale the control reads +so that the number of reads + +in the IP and +extract channel are + +the same in the regions +that are free of events. + +And so it matches +things, so it is 0.5. + +OK? + +AUDIENCE: Even if wasn't +0.5, wouldn't this rank list + +correct with that? + +PROFESSOR: No, it would not. + +Let us suppose that we +made a horrible mistake + +and that we let +these events through + +because our p was wrong. + +They would have a very +large number of reads, + +and they would be +very significant. + +As a consequence, +they would float up + +to the top of this list +as having the lowest + +p-values, or the +most significant, + +and they would pop through this. + +So we would report +them as binding events, + +which is not desirable. + +These are all great questions. + +Any other questions at all? + +So we've talked about this. + +The next question you +might have would be, + +you've done two replicates +of the same chip. + +You always want to do two of +every experiment, if not three + +or four. + +And I know it's +expensive, but you + +don't know where you are if +you only do one of something. + +Trust me. + +So assuming you've done +two experiments that + +were identical ChIP +experiments, and you + +would like to know +whether or not + +the results between those two +experiments are concordant. + +How might you go about +determining this? + +Does anybody have any ideas? + +Let me suggest something to you. + +Imagine that we +create two lists-- one + +for experiment x and +one for experiment y. + +And we're going to +put in this list, + +in rank order, the +strongest events + +and where they +occur in the genome. + +And let us suppose that we +are able to match events + +across experiments when +they're in the same location. + +So what we'll do is we'll +say Event one occurs here. + +Event 13 occurs here and here. + +Event 9 occurs here and here. + +Event 10 is matched. + +Event 11 occurs here. + +Event 57 occurs here. + +And these are ranked in +order of significance. + +They're not +completely concordant, + +and they're ranked according +to the significance + +in this particular experiment +and this particular experiment. + +And we would like to +know whether or not + +we think these two +experiments are + +good replicates of one another. + +Now the nice thing +about converting this + +into a rank test is +that we are no longer + +sensitive to the number of reads +or any specific numeric values + +represented by each +one of these events. + +We're simply ranking them +in terms of their importance + +and asking whether or not they +appear to be quite similar. + +So one way to do this is simply +to take a rank correlation, + +which is a correlation between +the ranks of identical events + +in the two lists. + +And so, for example, imagine +in the lower right-hand corner + +of this slide shows you an +example of X and Y values, + +although there's not really +a linear relationship + +between them, and the Pearson +correlation coefficient + +is 0.88. + +If we look at the right +correlation, which + +is defined by the equation +on the left, which is really + +simply the correlation +between their rank values, + +the Spearman correlation +for rank is 1. + +They're perfectly matched. + +So if you want to +consider whether or not + +two experiments +are very similar, + +I'd suggest you consider +rank based tests. + +But we can do even +more than this. + +Imagine that we +would like to know + +at what point along +this list things + +are no longer concordant, +that we would like to consider + +all the events that are +consistent among these two + +experiments. + +And we assume that there is +a portion of the experiment + +results that are concordant +and part that is discordant. + +And we want to learn +where the boundary is. + +So what we'll do is this. + +We will look at the number of +events that are concordant up + +to a particular point. + +Let's see here, make sure we +get the parametrization right. + +So if we have lists that +are n long, psi of n of t + +is the number of +events that are paired + +in the top n times t events. + +So t is simply the fraction. + +If is 0.25, that would +mean that in the top 25% + +of the events, the number +of events that are paired. + +Actually, it's the +fraction of events. + +Sorry. + +So assuming that we had perfect +replicates, what we would see + +would be that psi of n of +t would look like this. + +Yes? + +AUDIENCE: What is t? + +PROFESSOR: t is the +fraction of the events + +that we're considering. + +So this t might +be equal to 0.25. + +If this was 10, then this +would be-- oh, sorry. + +I think this t equal 0.5. + +If n was equal to 10, this +would be the first five events. + +So t is the fraction. + +n is the total number of events. + +So if this is t, which +is the fraction which + +goes from 0 to 1, and +this is psi of n of t, + +this would be a perfectly +matched set of replicates. + +A 0.5, 0.5 of the events are +matched, which is perfect. + +Can't do any better than that. + +So this is simply +telling us, as we + +take larger and larger +fractions of our event, what + +fraction of them are +matched up to that point? + +Question. + +AUDIENCE: So this assumes +that the rank order + +is important for the +correlation, right? + +The higher rank +they are, we expect + +them to be better correlated. + +For example, if +in the middle they + +were the best correlated, but +not the top or bottom in terms + +of the ranking, then you +might have a weird looking-- + +PROFESSOR: Yeah. + +The question is, +doesn't this assume + +that we care most +about the events + +up here, as opposed to +the events, for example, + +in the middle. + +And this analysis +is done to consider + +how many of the +top events we take + +that we think are consistent +across replicates. + +So it starts at the top as a +consequence of that assumption. + +This is the definition +of psi n, which + +is the fraction of +the top events that + +are paired in the top events. + +It's roughly linear +from the point + +where events are no +longer reproducible. + +And psi prime of n is the +derivative of that function. + +And graphically, if +we look at these, + +we can see that there's +perfect correspondence + +on the left point +up to some point. + +And then the hypothesis of this +irreproducible discovery rate + +is at that point things +stop being in correspondence + +because you've hit the noise +part of the event population. + +and you get to junk. + +And as soon as you get to +junk, things fall apart. + +And what this +methodology does is + +it attempts to fit the +distribution to both + +the correspondence and the +non-correspondence parts + +of the population, and you +get to set a parameter, which + +is the probability that you're +willing to accept something + +that's part of the +junk population + +of the non-correspondence +population. + +And the way this is used, for +example, in the ENCODE project + +is that all ChIP-seq experiments +are done in parallel. + +Event discovery is done +independently on them. + +All of the events from +each independent experiment + +are ranked from 1 to n. + +And then IDR is +done on the results + +to figure out +which of the events + +are consistent +across replicates. + +And obviously, if you've +had a very bad replicate, + +you get a very small number +of events, if any at all. + +But if you have good +replicates, then you + +get a large number of events. + +A secondary question is, imagine +you had processing algorithm A + +and processing algorithm B. +It might be that processing + +algorithm A typically +gave you more reproducible + +events than processing algorithm +B, that whenever you ran A, + +you could get much +further down this curve + +before things fell apart. + +Does that mean that A is +necessarily better, or not? + +What do you think? + +Would you always pick algorithm +A if that was the case? + +Any insight on this? + +Yes? + +AUDIENCE: No, probably, +because there's + +experimental +considerations to it. + +PROFESSOR: Yeah. + +I would go with [INAUDIBLE] +experimental considerations. + +But the reason +you might not pick + +it is it might be that if +algorithm A always gave you + +the same wrong answers +in the same order, + +it would score perfectly +on this, right? + +It doesn't mean that it's right. + +It just means it's consistent. + +So for example, it could +be calling all the towers + +as events, and it +could always give you, + +for every experiment, +the same results. + +In fact, one +interesting thing to do + +is to run this kind of analysis +against your experiment, + +and an outlier shouldn't +match your experiment. + +It should fail. + +It's always good to +run negative controls + +when you're doing data analysis. + +So this IDR analysis +simply allows + +you to pick alpha, which is +the probability of the rate + +of repairs for the +irreproducible part + +of the mixture that +you're willing to accept. + +And the way this is +used is, as I said, + +is that here you see +different ways of analyzing + +ChIP-seq data. + +And the little +vertical tick mark + +indicates how many +peaks they get + +before they can't go +any further because they + +hit the IDR bound alpha. + +And some methodologies can +produce far more events + +consistently than +other methods can. + +So that's just something +for you to keep in mind. + +And I will not have time to +present all the rest of this. + +But I did want to point +out one thing to you, which + +is that the methodology +we talked about today + +is able to resolve +where things are + +in the genome at exceptional +spatial resolution, + +within 20 base +pairs genome wide. + +And it's always run genome wide +at single base pair solution. + +And it can do +things like compute + +for pairs of +transcription factors + +that have been profiled +using ChIP-seq, + +the spacing between them for +spacings that are significant. + +And so you can see +that we're beginning + +to understand the regulatory +grammar of the genome in terms + +of the way factors +organize together + +and they interact to implement +the combinatorial switches + +that' we've talked about. + +That's it for today. + +You guys have been +totally great. + +We'll see you on +Tuesday for RNA-seq. + +And have a great +weekend until then. \ No newline at end of file diff --git a/P7a4bjE6Crk.txt b/P7a4bjE6Crk.txt new file mode 100644 index 0000000000000000000000000000000000000000..68fc319d73daddf79133139495f25864acad1a21 --- /dev/null +++ b/P7a4bjE6Crk.txt @@ -0,0 +1,2372 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high quality educational +resources for free. + +To make a donation or view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu. + +JOHN TSITSIKLIS: So today we're +going to finish with the + +core material of this class. + +That is the material that has to +do with probability theory + +in general. + +And then for the rest of the +semester we're going to look + +at some special types of models, +talk about inference. + +Well, there's also going to +be a small module of core + +material coming later. + +But today we're basically +finishing chapter four. + +And what we're going to do is +we're going to look at a + +somewhat familiar concept, the +concept of the conditional + +expectation. + +But we're going to look at it +from a slightly different + +angle, from a slightly more +sophisticated angle. + +And together with the +conditional expectation we + +will also talk about conditional +variances. + +It's something that we're going +to denote this way. + +And we're going to see what they +are, and there are some + +subtle concepts that +are involved here. + +And we're going to apply some +of the tools we're going to + +develop to deal with a special +type of situation in which + +we're adding random variables. + +But we're adding a random number +of random variables. + +OK, so let's start talking +about conditional + +expectations. + +I guess you know +what they are. + +Suppose we are in the discrete +the world. xy, or discrete + +random variables. + +We defined the conditional +expectation of x given that I + +told you the value of the +random variable y. + +And the way we define it is the +same way as an ordinary + +expectation, except that we're +using the conditional PMF. + +So we're using the probabilities +that apply to + +the new universe where we are +told the value of the random + +variable y. + +So this is still a familiar +concept so far. + +If we're dealing with the +continuous random variable x + +the formula is the same, except +that here we have an + +integral, and we have to use +the conditional density + +function of x. + +Now what I'm going to do, I want +to introduce it gently + +through the example that we +talked about last time. + +So last time we talked about +having a stick that has a + +certain length. + +And we take that stick, and we +break it at some point that we + +choose uniformly at random. + +And let's denote why the place +where we chose to break it. + +Having chosen y, then +we're left with a + +piece of the stick. + +And I'm going to choose a place +to break it once more + +uniformly at random +between 0 and y. + +So this is the second place at +which we are going to break + +it, and we call that place x. + +OK, so what's the conditional +expectation of x if I tell you + +the value of y? + +I tell you that capital Y +happens to take a specific + +numerical value. + +So this capital Y is now a +specific numerical value, x is + +chosen uniformly over +this range. + +So the expected value of x is +going to be half of this range + +between 0 and y. + +So the conditional expectation +is little y over 2. + +The important thing to realize +here is that this + +quantity is a number. + +I told you that the random +variable took a certain + +numerical value, +let's say 3.5. + +And then you tell me given that +the random variable took + +the numerical value 3.5 the +expected value of x is 1.75. + +So this is an equality +between numbers. + +On the other hand, before you +do the experiment you don't + +know what y is going +to turn out to be. + +So this little y is the +numerical value that has been + +observed when you start doing +the experiments and you + +observe the value of capital +Y. So in some sense this + +quantity is not known ahead of +time, it is random itself. + +So maybe we can start thinking +of it as a random variable. + +So to put it differently, before +we do the experiment I + +ask you what's the expected +value of x given y? + +You're going to answer me well +I don't know, it depends on + +what y is going to +turn out to be. + +So the expected value of x given +y itself can be viewed + +as a random variable, because +it depends on the random + +variable capital Y. + +So hidden here there's some kind +of statement about random + +variables instead of numbers. + +And that statement about +random variables, we + +write it this way. + +By thinking of the expected +value, the conditional + +expectation, as a random +variable instead of a number. + +It's a random variable when we +do not specify a specific + +number, but we think of it +as an abstract object. + +The expected value of x given +the random variable y is the + +random variable y over 2 no +matter what capital Y + +turns out to be. + +So we turn and take a statement +that deals with + +equality of two numbers, and we +make it a statement that's + +an equality between two +random variables. + +OK so this is clearly a random +variable because + +capital Y is random. + +What exactly is this object? + +I didn't yet define it +for you formally. + +So let's now give the formal +definition of this object + +that's going to be +denoted this way. + +The conditional expectation of +x given the random variable y + +is a random variable. + +Which random variable is it? + +It's the random variable that +takes this specific numerical + +value whenever capital Y happens +to take the specific + +numerical value little y. + +In particular, this is a random +variable, which is a + +function of the random variable +capital Y. In this + +instance, it's given by a simple +formula in terms of + +capital Y. In other situations +it might be a + +more complicated formula. + +So again, to summarize, +it's a random. + +The conditional expectation can +be thought of as a random + +variable instead of something +that's just a number. + +So in any specific context when +you're given the value of + +capital Y the conditional +expectation becomes a number. + +This is the realized value +of this random variable. + +But before the experiment +starts, before you know what + +capital Y is going to be, all +that you can say is that the + +conditional expectation is going +to be 1/2 of whatever + +capital Y turns out to be. + +This is a pretty subtle concept, +it's an abstraction, + +but it's a useful abstraction. + +And we're going to see +today how to use it. + +All right, I have made the point +that the conditional + +expectation, the random variable +that takes these + +numerical values is +a random variable. + +If it is a random variable +this means that it has an + +expectation of its own. + +So let's start thinking what +the expectation of the + +conditional expectation is +going to turn out to be. + +OK, so the conditional +expectation is a random + +variable, and in general it's +some function of the random + +variable y that we +are observing. + +In terms of numerical values if +capital Y happens to take a + +specific numerical value then +the conditional expectation + +also takes a specific numerical +value, and we use + +the same function +to evaluate it. + +The difference here is that this +is an equality of random + +variables, this is an equality +between numbers. + +Now if we want to calculate +the expected value of the + +conditional expectation we're +basically talking about the + +expected value of a function +of a random variable. + +And we know how to calculate +expected values of a function. + +If we are in the discrete case, +for example, this would + +be a sum over all y's of the +function who's expected value + +we're taking times the +probability that y takes on a + +specific numerical value. + +OK, but let's remember +what g is. + +So g is the numerical value +of the conditional + +expectation of x with y. + +And now when you see this +expression you recognize it. + +This is the expression +that we get in the + +total expectation theorem. + +Did I miss something? + +Yes, in the total expectation +theorem to find the expected + +value of x, we divide the world +into different scenarios + +depending on what y happens. + +We calculate the expectation +in each one of the possible + +worlds, and we take the +weighted average. + +So this is a formula that you +have seen before, and you + +recognize that this is the +expected value of x. + +So this is a longer, more +detailed derivation of what I + +had written up here, but the +important thing to keep in + +mind is the moral of the +story, the punchline. + +The expected value of the +conditional expectation is the + +expectation itself. + +So this is just our total +expectation theorem, but + +written in more abstract +notation. + +And it comes handy to have this +more abstract notation, + +as as we're going to +see in a while. + +OK, we can apply this to +our stick example. + +If we want to find the expected +value of x how much + +of the stick is left +at the end? + +We can calculate it using this +law of iterated expectations. + +It's the expected value of the +conditional expectation. + +We know that the conditional +expectation is y over 2. + +So expected value of y is l over +2, because y is uniform + +so we get l over 4. + +So this gives us the same answer +that we derived last + +time in a rather long way. + +All right, now that we have +mastered conditional + +expectations, let's raise the +bar a little more and talk + +about conditional variances. + +So the conditional expectation +is the mean value, or the + +expected value, in a conditional +universe where + +you're told the value of y. + +In that same conditional +universe you can talk about + +the conditional distribution +of x, which has a mean-- + +the conditional expectation-- + +but the conditional +distribution of + +x also has a variance. + +So we can talk about the +variance of x in that + +conditional universe. + +The conditional variance as a +number is the natural thing. + +It's the variance of x, except +that all the calculations are + +done in the conditional +universe. + +In the conditional universe the +expected value of x is the + +conditional expectation. + +This is the distance from the +mean in the conditional + +universe squared. + +And we take the average value +of the squared distance, but + +calculate it again using the +probabilities that apply in + +the conditional universe. + +This is an equality +between numbers. + +I tell you the value of y, once +you know that value for y + +you can go ahead and plot the +conditional distribution of x. + +And for that conditional +distribution you can calculate + +the number which is the +variance of x in that + +conditional universe. + +So now let's repeat the mental +gymnastics from the previous + +slide, and abstract things, and +define a random variable-- + +the conditional variance. + +And it's going to be a random +variable because we leave the + +numerical value of capital +Y unspecified. + +So ahead of time we don't know +what capital Y is going to be, + +and because of that we don't +know ahead of time what the + +conditional variance +is going to be. + +So before the experiment starts +if I ask you what's the + +conditional variance of x? + +You're going to tell me well I +don't know, It depends on what + +y is going to turn out to be. + +It's going to be something +that depends on y. + +So it's a random variable, +which is a function of y. + +So more precisely, the +conditional variance when + +written in this notation just +with capital letters, is a + +random variable. + +It's a random variable whose +value is completely determined + +once you learned the value of +capital Y. And it takes a + +specific numerical value. + +If capital Y happens to get a +realization that's a specific + +number, then the variance also +becomes a specific number. + +And it's just a conditional +variance of y + +over x in that universe. + +All right, OK, so let's continue +what we did in the + +previous slide. + +We had the law of iterated +expectations. + +That told us that expected +value of a conditional + +expectation is the unconditional +expectation. + +Is there a similar rule that +might apply in this context? + +So you might guess that the +variance of x could be found + +by taking the expected value of +the conditional variance. + +It turns out that this +is not true. + +There is a formula for the +variance in terms of + +conditional quantities. + +But the formula is a little +more complicated. + +If involves two terms +instead of one. + +So we're going to go +quickly through the + +derivation of this formula. + +And then, through examples +we'll try to get some + +interpretation of what the +different terms here + +correspond to. + +All right, so let's try +to prove this formula. + +And the proof is sort of a +useful exercise to make sure + +you understand all the symbols +that are involved in here. + +So the proof is not difficult, +it's 4 and 1/2 lines of + +algebra, of just writing +down formulas. + +But the challenge is to make +sure that at each point you + +understand what each one +of the objects is. + +So we go into formula for +the variance affects. + +We know in general that the +variance of x has this nice + +expression that we often +use to calculate it. + +The expected value of the +squared of the random variable + +minus the mean squared. + +This formula, for the variances, +of course it should + +apply to conditional +universes. + +I mean it's a general formula +about variances. + +If we put ourselves in a +conditional universe where the + +random variable y is given to us +the same math should work. + +So we should have a similar +formula for + +the conditional variances. + +It's just the same formula, +but applied to + +the conditional universe. + +The variance of x in the +conditional universe is the + +expected value of x squared-- + +in the conditional universe-- + +minus the mean of x-- in the +conditional universe-- + +squared. + +So this formula looks fine. + +Now let's take expected +values of both sides. + +Remember the conditional +variance is a random variable, + +because its value depends on +whatever realization we get + +for capital Y. So we can +take expectations here. + +We get the expected value +of the variance. + +Then we have the expected +value of a conditional + +expectation. + +Here we use the fact that +we discussed before. + +The expected value of a +conditional expectation is the + +same as the unconditional +expectation. + +So this term becomes this. + +And finally, here we just have +some weird looking random + +variable, and we take the +expected value of it. + +All right, now we need to do +something about this term. + +Let's use the same +rule up here to + +write down this variance. + +So variance of an expectation, +that's kind of strange, but + +you remember that the +conditional expectation is + +random, because y is random. + +So this thing is a random +variable, so + +this thing has a variance. + +What is the variance +of this thing? + +It's the expected value of the +thing squared minus the square + +of the expected value +of the thing. + +Now what's the expected +value of that thing? + +By the law of iterated +expectations, once more, the + +expected value of this thing +is the unconditional + +expectation. + +And that's why here I put the +unconditional expectation. + +So I'm using again this general +rule about how to + +calculate variances, and I'm +applying it to calculate the + +variance of the conditional +expectation. + +And now you notice that if you +add these two expressions c + +and d we get this plus +that, which is this. + +It's equal to-- + +these two terms cancel, we're +left with this minus that, + +which is the variance of x. + +And that's the end +of the proof. + +This one of those proofs that +do not convey any intuition. + +This, as I said, it's a useful +proof to go through just to + +make sure you understand +the symbols. + +It starts to get pretty +confusing, and a little bit on + +the abstract side. + +So it's good to understand +what's going on. + +Now there is intuition behind +this formula, some of which is + +better left for later +in the class when + +we talk about inference. + +The idea is that the conditional +expectation you + +can interpret it as an estimate +of the random + +variable that you +are trying to-- + +an estimate of x based on +measurements of y, you can + +think of these variances as +having something to do with an + +estimation error. + +And once you start thinking in +those terms an interpretation + +will come about. + +But again as I said this is +better left for when we start + +talking about inference. + +Nevertheless, we're going to get +some intuition about all + +these formulas by considering +a baby example where we're + +going to apply the law of +iterated expectations, and the + +law of total variance. + +So the baby example is that we +do this beautiful experiment + +of giving a quiz to a class +consisting of many sections. + +And we're interested in +two random variables. + +So we have a number of students, +and they're all + +allocated to sections. + +The experiment is that I pick +a student at random, and I + +look at two random variables. + +One is the quiz score of the +randomly selected student, and + +the other random variable is +the section number of the + +student that I have selected. + +We're given some statistics +about the two sections. + +Section one has 10 students, +section two has 20 students. + +The quiz average in section +one was 90. + +Quiz average in section +two was 60. + +What's the expected +value of x? + +What's the expected quiz score +if I pick a student at random? + +Well, each student has the same + +probability of being selected. + +I'm making that assumption +out of the 30 students. + +I need to add the quiz scores +of all of the students. + +So I need to add the quiz scores +in section one, which + +is 90 times 10. + +I need to add the quiz scores +in that section, + +which is 60 times 20. + +And we find that the overall +average was 70. + +So this is the usual +unconditional expectation. + +Let's look at the conditional +expectation, and let's look at + +the elementary version +where we're talking + +about numerical values. + +If I tell you that the randomly +selected student was + +in section one what's the +expected value of the quiz + +score of that student? + +Well, given this information, +we're picking a random student + +uniformly from that section in +which the average was 90. + +The expected value of the +score of that student + +is going to be 90. + +So given the specific value of +y, the specific section, the + +conditional expectation or the +expected value of the quiz + +score is a specific number, +the number 90. + +Similarly for the second section +the expected value is + +60, that's the average score +in the second section. + +This is the elementary +version. + +What about the abstract +version? + +In the abstract version the +conditional expectation is a + +random variable because +it depends. + +In which section is the +student that I picked? + +And with probability 1/3, I'm +going to pick a student in the + +first section, in which case +the conditional expectation + +will be 90, and with probability +2/3 I'm going to + +pick a student in the +second section. + +And in that case the conditional +expectation will + +take the value of 60. + +So this illustrates the idea +that the conditional + +expectation is a random +variable. + +Depending on what y is going +to be, the conditional + +expectation is going to be one +or the other value with + +certain probabilities. + +Now that we have the +distribution of the + +conditional expectation +we can calculate the + +expected value of it. + +And the expected value of such a +random variable is 1/3 times + +90, plus 2/3 times 60, and +it comes out to equal 70. + +Which miraculously is the same +number that we got up there. + +So this tells you that you can +calculate the overall average + +in a large class by taking the +averages in each one of the + +sections and weighing each one +of the sections according to + +the number of students +that it has. + +So this section had 90 students +but only 1/3 of the + +students, so it gets +a weight of 1/3. + +So the law of iterated +expectations, once more, is + +nothing too complicated. + +It's just that you can calculate +overall class + +average by looking +at the section + +averages and combine them. + +Now since the conditional +expectation is a random + +variable, of course it has +a variance of it's own. + +So let's calculate +the variance. + +How do we calculate variances? + +We look at all the possible +numerical values of this + +random variable, which +are 90 and 60. + +We look at the difference of +those possible numerical + +values from the mean of this +random variable, and the mean + +of that random variable, we +found that's it's 70. + +And then we weight the different +possible numerical + +values according to their +probabilities. + +So with probability 1/3 the +conditional expectation is 90, + +which is 20 away +from the mean. + +And we get this squared +distance. + +With probability 2/3 the +conditional expectation is 60, + +which is 10 away from the +mean, has this squared + +distance and gets weighed +by 2/3, which is the + +probability of 60. + +So you do the numbers, and you +get the value for the variance + +equal to 200. + +All right, so now we want to +move towards using that more + +complicated formula involving +the conditional variances. + +OK, suppose someone goes and +calculates the variance of the + +quiz scores inside each +one of the sections. + +So someone gives us these two +pieces of information. + +In section one we take the +differences from the mean in + +that section, and let's say that +the various turns out to + +be a number equal +to 10 similarly + +in the second section. + +So these are the variances +of the quiz scores inside + +individual sections. + +The variance in one conditional +universe, the + +variance in the other +conditional universe. + +So if I pick a student in +section one and I don't tell + +you anything more about the +student, what's the variance + +of the random score +of that student? + +The variance is 10. + +I know why, but I don't +know the student. + +So the score is still a random +variable in that universe. + +It has a variance, and +that's the variance. + +Similarly, in the other +universe, the variance of the + +quiz scores is this +number, 20. + +Once more, this is an equality +between numbers. + +I have fixed the specific +value of y. + +So I put myself in a specific +universe, I can calculate the + +variance in that specific +universe. + +If I don't specify a numerical +value for capital Y, and say I + +don't know what Y is going to +be, it's going to be random. + +Then what kind of section +variance I'm going to get + +itself will be random. + +With probability 1/3, I pick a +student in the first section + +in which case the conditional +variance given what I have + +picked is going to be 10. + +Or with probability 2/3 I pick +y equal to 2, and I place + +myself in that universe. + +And in that universe the +conditional variance is 20. + +So you see again from here that +the conditional variance + +is a random variable that takes +different values with + +certain probabilities. + +And which value it takes depends +on the realization of + +the random variable capital Y. +So this happens if capital Y + +is one, this happens if capital +Y is equal to 2. + +Once you have something +of this form-- + +a random variable that takes +values with certain + +probabilities-- + +then you can certainly calculate +the expected value + +of that random variable. + +Don't get intimidated by the +fact that this random + +variable, it's something that's +described by a string + +of eight symbols, or +seven, instead of + +just a single letter. + +Think of this whole string of +symbols there as just being a + +random variable. + +You could call it z for example, +use one letter. + +So z is a random variable that +takes these two values with + +these corresponding +probabilities. + +So we can talk about the +expected value of Z, which is + +going to be 1/3 times 10, 2/3 +times 20, and we get a certain + +number from here. + +And now we have all the pieces +to calculate the overall + +variance of x. + +The formula from the previous +slide tells us this. + +Do we have all the pieces? + +The expected value of +the variance, we + +just calculated it. + +The variance of the expected +value, this was the last + +calculation in the +previous slide. + +We did get a number for +it, it was 200. + +You add the two, you find +the total variance. + +Now the useful piece of this +exercise is to try to + +interpret these two numbers, +and see what they mean. + +The variance of x given y for +a specific y is the variance + +inside section one. + +This is the variance +inside section two. + +The expected value is some +kind of average of the + +variances inside individual +sections. + +So this term tells us +something about the + +variability of this course, +how widely spread they are + +within individual sections. + +So we have three sections, and +this course happens to be-- + +OK, let's say the sections +are really different. + +So here you have undergraduates +and here you + +have post-doctoral students. + +And these are the quiz scores, +that's section one, section + +two, section three. + +Here's the mean of the +first section. + +And the variance has something +to do with the spread. + +The variance in the second +section has something to do + +with the spread, similarly +with the third spread. + +And the expected value of the +conditional variances is some + +weighted average of the three +variances that we get from + +individual sections. + +So variability within sections +definitely contributes + +something to the overall +variability of this course. + +But if you ask me about the +variability over the entire + +class there's a second effect. + +That has to do with the fact +that different sections are + +very different from +each other. + +That these courses here are far +away from those scores. + +And this term is the one +that does the job. + +This one looks at the expected +values inside each section, + +and these expected values are +this, this, and that. + +And asks a question how widely +spread are they? + +It asks how different from +each other are the means + +inside individual sections? + +And in this picture it would be +a large number because the + +difference section means +are quite different. + +So the story that this formula +is telling us is that the + +overall variability of the quiz +scores consists of two + +factors that can be quantified +and added. + +One factor is how much +variability is there inside + +individual sections? + +And the other factor is how +different are the sections + +from each other? + +Both effects contribute +to the overall + +variability of this course. + +Let's continue with just one +more numerical example. + +Just to get the hang of doing +these kinds of calculations, + +and apply this formula to do a +divide and conquer calculation + +of the variance of a +random variable. + +Just for variety now we're going +to take a continuous + +random variable. + +Somebody gives you a PDF if this +form, and they ask you + +for the variance. + +And you say oh that's too +complicated, I don't want to + +do integrals. + +Can I divide and conquer? + +And you say OK, let me do +the following trick. + +Let me define a random +variable, y. + +Which takes the value 1 if x +falls in here, and takes the + +value 2 if x falls in +the second interval. + +And let me try to work in the +conditional world where things + +might be easier, and then +add things up to + +get the overall variance. + +So I have defined y this +particular way. + +In this example y becomes +a function of x. + +y is completely determined +by x. + +And I'm going to calculate the +overall variance by trying to + +calculate all of the terms +that are involved here. + +So let's start calculating. + +First observation is that this +event has probability 1/3, and + +this event has probability +2/3. + +The expected value of x given +that we are in this universe + +is 1/2, because we +have a uniform + +distribution from 0 to 1. + +Here we have a uniform +distribution from 1 to 2, so + +the conditional expectation of +x in that universe is 3/2. + +How about conditional +variances? + +In the world who are y is equal +to 1 x has a uniform + +distribution on a +unit interval. + +What's the variance of x? + +By now you've probably seen that +formula, it's 1 over 12. + +1 over 12 is the variance of a +uniform distribution over a + +unit interval. + +When y is equal to 2 the +variance is again 1 over 12. + +Because in this instance again +x has a uniform distribution + +over an interval +of unit length. + +What's the overall expected +value of x? + +The way you find the overall +expected value is to consider + +the different numerical values +of the conditional + +expectation. + +And weigh them according +to their probabilities. + +So with probability 1/3 +the conditional + +expectation is 1/2. + +And with probability +2/3 the conditional + +expectation is 3 over 2. + +And this turns out +to be 7 over 6. + +So this is the advance work +we need to do, now let's + +calculate a few things here. + +What's the variance of the +expected value of x given y? + +Expected value of x given y is +a random variable that takes + +these two values with +these probabilities. + +So to find the variance we +consider the probability that + +the expected value takes the +numerical value of 1/2 minus + +the mean of the conditional +expectation. + +What's the mean of the +conditional expectation? + +It's the unconditional +expectation. + +So it's 7 over 6. + +We just did that calculation. + +So I'm putting here that number, +7 over 6 squared. + +And then there's a second term +with probability 2/3, the + +conditional expectation takes +this value of 3 over 2, which + +is so much away from the mean, +and we get this contribution. + +So this way we have calculated +the variance of the + +conditional expectation, +this is this term. + +What is this? + +Any guesses what +this number is? + +It's 1 over 12, why? + +The conditional variance just +happened in this example to be + +1 over 12 no matter what. + +So the conditional variance +is a deterministic random + +variable that takes +a constant value. + +So the expected value of +this random variable + +is just 1 over 12. + +So we got the two pieces that we +need, and so we do have the + +overall variance of the +random variable x. + +So this was just an academic +example in order to get the + +hang of how to manipulate +various quantities. + +Now let's use what we have +learned and the tools that we + +have to do something a little +more interesting. + +OK, so by now you're all in +love with probabilities. + +So over the weekend you're going +to bookstores to buy + +probability books. + +So you're going to visit a +random number bookstores, and + +at each one of the bookstores +you're going to spend a random + +amount of money. + +So let n be the number of stores +that you are visiting. + +So n is an integer-- + +non-negative random variable-- + +and perhaps you know +the distribution + +of that random variable. + +Each time that you walk into a +store your mind is clear from + +whatever you did before, and you +just buy a random number + +of books that has nothing to +do with how many books you + +bought earlier on the day. + +It has nothing to do with +how many stores you are + +visiting, and so on. + +So each time you enter as a +brand new person, and buy a + +random number of books, +and spend a + +random amount of money. + +So what I'm saying, more +precisely, is that I'm making + +the following assumptions. + +That for each store i-- + +if you end up visiting +the i-th store-- + +the amount of money that you +spend is a random variable + +that has a certain +distribution. + +That distribution is the same +for each store, and the xi's + +from store to store are +independent from each other. + +And furthermore, the xi's are +all independent of n. + +So how much I'm spending at the +store-- once I get in-- + +has nothing to do with how +many stores I'm visiting. + +So this is the setting that +we're going to look at. + +y is the total amount of money +that you did spend. + +It's the sum of how much you +spent in the stores, but the + +index goes up to capital N. +And what's the twist here? + +It's that we're dealing with the +sum of independent random + +variables except that how many +random variables we have is + +not given to us ahead of time, +but it is chosen at random. + +So it's a sum of a random number +of random variables. + +We would like to calculate some +quantities that have to + +do with y, in particular the +expected value of y, or the + +variance of y. + +How do we go about it? + +OK, we know something about the +linearity of expectations. + +That expectation of a sum is the +sum of the expectations. + +But we have used that rule only +in the case where it's + +the sum of a fixed number +of random variables. + +So expected value of x plus y +plus z is expectation of x, + +plus expectation of y, plus +expectation of z. + +We know this for a fixed number +of random variables. + +We don't know it, or how it +would work for the case of a + +random number. + +Well, if we know something +about the case for fixed + +random variables let's transport +ourselves to a + +conditional universe where the +number of random variables + +we're summing is fixed. + +So let's try to break the +problem divide and conquer by + +conditioning on the different +possible values of the number + +of bookstores that +we're visiting. + +So let's work in the conditional +universe, find the + +conditional expectation in this +universe, and then use + +our law of iterated expectations +to see what + +happens more generally. + +If I told you that I visited +exactly little n stores, where + +little n now is a number, +let's say 10. + +Then the amount of money you're +spending is x1 plus x2 + +all the way up to x10 given +that we visited 10 stores. + +So what I have done here is that +I've replaced the capital + +N with little n, and I can do +this because I'm now in the + +conditional universe +where I know that + +capital N is little n. + +Now little n is fixed. + +We have assumed that n is +independent from the xi's. + +So in this universe of a fixed +n this information here + +doesn't tell me anything new +about the values of the x's. + +If you're conditioning random +variables that are independent + +from the random variables you +are interested in, the + +conditioning has no effect, +and so it can be dropped. + +So in this conditional universe +where you visit + +exactly 10 stores the expected +amount of money you're + +spending is the expectation of +the amount of money spent in + +10 stores, which is the sum of +the expected amount of money + +in each store. + +Each one of these is the same +number, because the random + +variables have identical +distributions. + +So it's n times the expected +value of money you spent in a + +typical store. + +This is almost obvious without +doing it formally. + +If I'm telling you that you're +visiting 10 stores, what you + +expect to spend is 10 times the +amount you expect to spend + +in each store individually. + +Now let's take this equality +here and rewrite it in our + +abstract notation, in terms +of random variables. + +This is an equality +between numbers. + +Expected value of y given that +you visit 10 stores is 10 + +times this particular number. + +Let's translate it into +random variables. + +In random variable notation, +the expected value of money + +you're spending given the +number of stores-- + +but without telling you +a specific number-- + +is whatever that number of +stores turns out to be times + +the expected value of x. + +So this is a random variable +that takes this as a numerical + +value whenever capital +N happens to be + +equal to little n. + +This is a random variable, which +by definition takes this + +numerical value whenever +capital N is + +equal to little n. + +So no matter what capital N +happens to be what specific + +value, little n, it takes +this is equal to that. + +Therefore the value of this +random variable is going to be + +equal to that random variable. + +So as random variables, these +two random variables are equal + +to each other. + +And now we use the law of +iterated expectations. + +The law of iterated expectations +tells us that the + +overall expected value of y is +the expected value of the + +conditional expectation. + +We have a formula for the +conditional expectation. + +It's n times expected +value of x. + +Now the expected value +of x is a number. + +Expected value of something +random times a number is + +expected value of the +random variable + +times the number itself. + +We can take a number outside +the expectation. + +So expected value of +x gets pulled out. + +And that's the conclusion, +that overall the expected + +amount of money you're going to +spend is equal to how many + +stores you expect to visit on +the average, and how much + +money you expect to spend on +each one on the average. + +You might have guessed that +this is the answer. + +If you expect to visit 10 +stores, and you expect to + +spend $100 on each store, then +yes, you expect to spend + +$1,000 today. + +You're not going to impress your +Harvard friends if you + +tell them that story. + +It's one of the cases where +reasoning, on the average, + +does give you the plausible +answer. + +But you will be able to impress +your Harvard friends + +if you tell them that I can +actually calculate the + +variance of how much +I can spend. + +And we're going to work by +applying this formula that we + +have, and the difficulty is +basically sorting out all + +those terms here, and +what they mean. + +So let's start with this term. + +So the expected value of y given +that you're visiting n + +stores is n times the +expected value of x. + +That's what we did in +the previous slide. + +So this thing is a random +variable, it has a variance. + +What is the variance? + +Is the variance of n times +the expected value of x. + +Remember expected value +of x is a number. + +So we're dealing with the +variance of n times a number. + +What happens when you +multiply a random + +variable by a constant? + +The variance becomes the +previous variance times the + +constant squared. + +So the variance of this is the +variance of n times the square + +of that constant that +we had here. + +So this tells us the variance +of the expected + +value of y given n. + +This is the part of the +variability of how much money + +you're spending, which is +attributed to the randomness, + +or the variability, in +the number of stores + +that you are visiting. + +So the interpretation of the +two terms is there's + +randomness in how much you're +going to spend, and this is + +attributed to the randomness +in the number of stores + +together with the randomness +inside individual stores. + +Well, after I tell you how many +stores you're visiting. + +So now let's deal with this +term-- the variance inside + +individual stores. + +Let's take it slow. + +If I tell you that you're +visiting exactly little n + +stores, then y is how much +money you spent in those + +little n stores. + +You're dealing with the sum of +little n random variables. + +What is the variance +of the sum of + +little n random variables? + +It's the sum of their +variances. + +So each store contributes a +variance of x, and you're + +adding over little n stores. + +That's the variance of money +spent if I tell you + +the number of stores. + +Now let's translate this into +random variable notation. + +This is a random variable that +takes this numerical value + +whenever capital N is +equal to little n. + +This is a random variable that +takes this numerical value + +whenever capital N is +equal to little n. + +This is equal to that. + +Therefore, these two are always +equal, no matter what + +happens to y. + +So we have an equality here +between random variables. + +Now we take expectations +of both. + +Expected value of the variance +is expected value of this. + +OK it may look confusing to +think of the expected value of + +the variance here, but the +variance of x is a number, not + +a random variable. + +You think of it as a constant. + +So its expected value of n times +a constant gives us the + +expected value of n times +the constant itself. + +So now we got the second term +as well, and now we put + +everything together, this plus +that to get an expression for + +the overall variance of y. + +Which again, as I said before, +the overall variability in y + +has to do with the variability +of how much you spent inside + +the typical store. + +And the variability in +the number of stores + +that you are visiting. + +OK, so this is it for today. + +We'll change subjects quite +radically from next time. \ No newline at end of file diff --git a/PGnLAx8e4Gk.txt b/PGnLAx8e4Gk.txt new file mode 100644 index 0000000000000000000000000000000000000000..c9c620e1d2eae786c70a562a1118f0389e03db0f --- /dev/null +++ b/PGnLAx8e4Gk.txt @@ -0,0 +1,3497 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help +MIT OpenCourseWare + +continue to offer high quality +educational resources for free. + +To make a donation or +view additional materials + +from hundreds of MIT courses, +visit MIT OpenCourseWare + +at ocw.mit.edu + +MEHRAN KARDAR: OK, let's start. + +So in this class, +we focused mostly + +on having some slab of material +and having some configuration + +of some kind of a field inside. + +And we said that, +basically, we are + +going to be interested +close to, let's say, + +phase transition and some +quantity that changes + +at the phase transition. + +We are interested in figuring +out the singularities + +associated with that. + +And we can coarse grain. + +Once we have coarse grained, we +have the field m, potentially + +a vector, that is characterized +throughout this material. + +So it's a field +that's function of x. + +And by integrating out over +a lot of degrees of freedom, + +we can focus on the +probability of finding + +different configurations +of this field. + +And this probability +we constructed + +on the basis of a number +of simple assumptions + +such as locality, which +implied that we would write + +this probability as a +product of contributions + +of different parts, which in the +exponent becomes an integral. + +And then we would put +within this all kinds + +of things that are consistent +with the symmetries + +of the problem. + +So if, for example, +this is a field that + +is invariant on +the rotations, we + +would be having terms such as +m squared, m to the fourth, + +and so forth. + +But the interesting thing +was that, of course, + +there is some interaction +with the neighborhoods. + +Those neighborhood interactions +we can, in the continuum limit, + +inclement by putting terms that +are proportional to radiant + +of m and so forth. + +So there is a lot +of things that you + +could put consistent +with symmetry + +and presumably be as +general as possible. + +You could have +this and the terms + +in this coefficients +of this expansion would + +be these phenomenological +parameters characterizing + +this probability, +function of all kinds + +of microscopic +degrees of freedom, + +as well as microscopic +constraints + +such as temperature, +pressures, et cetera. + +Now the question that we have +is if I start with a system, + +let's say a configuration +where everybody's pointing up + +or some other configuration +that is not the equilibrium + +configuration, how +does the probability + +evolve to become +something like this? + +Now we are interested +therefore in m + +that is a function +of position and time. + +And since I want to use t for +time, this coefficient of m + +squared that we were +previously calling t, + +I will indicate by r, OK? + +There are various types +of dynamics that you + +can look at for this problem. + +I will look at the class +that is dissipative. + +And its inspiration +is the Brownian motion + +that we discussed +last time where + +we saw that when you put +a particle in a fluid + +to a very good approximation +when the fluid is viscous, + +it is the velocity that is +proportional to the force + +and you can't ignore inertial +effects such as mass times + +acceleration and you +write an equation + +that is linear in position. + +Velocity is the +linear derivative + +of position, which +is the variable that + +is of interest to you. + +So here the variable that +is of interest to us, + +is this magnetization that is +changing as a function of time. + +And the equation +that we write down + +is the derivative of this +field with respect to time. + +And again, for the +Brownian motion, + +the velocity was +proportional to the force. + +The constant of proportionality +was some kind of a mobility + +that you would +have in the fluid. + +So continuing with +that inspiration, + +let's put some kind +of a mobility here. + +I should really put a +vector field here, but just + +for convenience, let's +just focus on one component + +and see what happens. + +Now what is the force? + +Presumably, each +location individually + +feels some kind of a force. + +And typically when we had the +Brownian particle, the force + +we were getting +from the derivative + +of the potential with +respect to the [? aviation ?] + +of the position, the field +that we are interested. + +So the analog of our +potential is the energy + +that we have over here, +and in the same sense + +that we want this effective +potential, if you like, + +to govern the +equilibrium behavior-- + +and again, recall that for the +case of the Brownian particle, + +eventually the probability was +related to the potential by e + +to the minus beta v. This +is the analog of beta v, now + +considered in the entire field. + +So the analog of the force is +a derivative of this beta H, + +so this would be our beta H +with respect to the variable + +that I'm trying to change. + +And since I don't have just +one variable, but a field, + +the analog of the derivative +becomes this functional + +derivative. + +And in the same sense that +the Brownian particle, + +the Brownian motion, +is trying to pull you + +towards the minimum +of the potential, + +this is an equation that, +if I kind of stop over here, + +tries to put the particle +towards the minimum + +of this beta H. + +Now the reason that the Brownian +particle didn't go and stick + +at one position, which was +the minimum, but fluctuated, + +was of course, that we +added the random force. + +So there is some kind of an +analog of a random force that + +we can put either in front of +[? mu ?] or imagine that if we + +added it to [? mu, ?] +and we put it over here. + +Now for the case of +the Brownian particle, + +the assumption was that if +I evaluate eta at some time, + +and eta at another +time t2 and t1, + +that this was related to 2D +delta function t1 minus t2. + +Now of course here, at each +location, I have a noise term. + +So this noise carries +an index, which + +indicates the position, which +is, of course, a vector in D + +dimension in principal. + +And there is no reason to +imagine that the noise here + +that comes from all kinds of +microscopic degrees of freedom + +that we have +integrated out should + +have correlation with the +noise at some other point. + +So the simplest assumption is +to also put the delta function + +in the positions, OK? + +So if I take this beta +H that I have over there + +and take the functional +derivative, what do I get? + +I will get that the m of xt by +dt is the function of-- oops, + +and I forgot to put a +the minus sign here. + +The force is minus +the potential, + +and this is basically +going down the gradient, + +so I need to put that. + +So I have to take a +derivative of this. + +First of all I can take +a derivative with respect + +to m itself. + +I will get minus rm. + +Well, actually, let's +put the minus out front. + +And then I will get +the derivative of m + +to the fourth, which is +[? 4umq, ?] all kinds of terms + +like this. + +Then the terms that come +from the derivatives + +and taking the derivative +with respect to gradient + +will give me K +times the gradient. + +But then in the +functional derivative, + +I have to take +another derivative, + +converting this to minus +K log Gaussian of m. + +And then I would have +L the fourth derivative + +from the next term and so forth. + +And on top of +everything else, I will + +have the noise who's statistics +I have indicated above. + +So this entity, +this equation, came + +from the Landau-Ginzburg +model, and it + +is called a time dependent +Landau-Ginzburg equation. + +And so would be the analog of +the Brownian type of equation, + +now for an entire field. + +Now we're going to have +a lot of difficulty + +in the short amount of time +that is left to us to deal + +with this nonlinear +equation, so we + +are going to do the same +thing that we did in order + +to capture the properties +of the Landau-Ginzburg model + +qualitatively. + +Which is to ignore +nonlinearities, + +so it's a kind of Gaussian +version of the model. + +So what we did +was we linearized. + +AUDIENCE: Question. + +MEHRAN KARDAR: Yes? + +AUDIENCE: Why does the +sign in front of the K term + +change relative to the others? + +MEHRAN KARDAR: OK, so when you +have the function 0 of a field + +gradient, et +cetera, you can show + +that the functional +derivative, the first term + +is the ordinary +type of derivative. + +And then if you think about the +variations that are carrying m + +and with the gradient and you +write it as m plus delta m + +and then make sure that you +take the delta m outside, + +you need to do an integration +by part that changes the sign. + +And the next term +would be the gradient + +of the phi by the [? grad ?] +m, and the next term + +would be log [INAUDIBLE] +of [INAUDIBLE] gradient + +of m squared and so forth. + +It alternates and so by +explicitly calculating + +the difference of +two functionals + +with this integration evaluated +at m and m plus delta m + +and pulling out everything +that is proportional to delta m + +you can prove these expressions. + +So we linearize this equation, +which I've already done that. + +I cross out the mq term and +any other nonlinear terms, + +so I only keep the linear term. + +And then I do a +Fourier transform. + +So basically I switch from +the position representation + +to the Fourier transform that's +called m tilde of q, I think. + +x is replaced with q. + +And then the equation +for the field m linears. + +The form separates out +into independent equations + +for the components that +are characterized by q. + +So the Fourier transform of the +left hand side is just this. + +Fourier transform of +the right hand side + +will give me minus mu +r plus K q squared. + +The derivative of [INAUDIBLE] +will give me a minus q squared. + +The derivative of the next term +L q to the forth, et cetera. + +And I've only kept +the linear term, + +so I have m tilde of q and t. + +And then I have the +Fourier transforms + +of the noise eta of x and t. + +They [? call it ?] eta +tilde of q [? m. ?] + +So you can see that +each mode satisfy + +a separate linear equation. + +So this equation is +actually very easy + +to solve for any linear +equation m tilde of q and t. + +If I didn't have the +noise, so I would + +start with some value +at t [? close ?] to 0, + +and that value would +decay exponentially + +in the characteristic time +that I will call tao of q. + +And 1 over tao of q is +simply this mu r plus K q2 + +and so forth. + +Now once you have noise, +essentially each one + +of these noises acts like +an initial condition. + +And so the full +answer is an integral + +over all of these noises from +0 tilde time t of interest. + +Dt prime the noise that +occurs at a time t prime, + +and the noise that occurs at +time t [? trime ?] relaxes + +with this into the minus +t minus t prime tao of q. + +So that's the solution to +that linear noisy equations, + +basically [? sequencing ?] +[INAUDIBLE]. + +So one of the things +that we now see + +is that essentially the +different Fourier components + +of the field. + +Each one of them +is independently + +relaxing to something, +and each one of them + +has a characteristic +relaxation time. + +As I go towards smaller +and smaller values of q, + +this rate becomes smaller, +and the relaxation time + +becomes larger. + +So essentially shortwave +wavelength modes + +that correspond to large +q, they relax first. + +Longer wavelength modes +will relax later on. + +And you can see that the largest +relaxation time, tao max, + +corresponds to q equals to 0 +is simply 1 over [? nu ?] r. + +So I can pluck this to a +max as a function of r, + +and again in this theory, +the Gaussian theory, + +we saw only makes sense as +long as all is positive. + +So I have to look only +on the positive axis. + +And I find that +the relaxation time + +for the entire system for +the longest wavelength + +actually diverges +as r goes to 0. + +And recall that r, +in our perspective, + +is really something that is +proportional to T minus Tc. + +So basically we find that +as we are approaching + +the critical point, +the time it takes + +for the entirety of the +system or the longest + +wavelength [? modes ?] to relax +diverges as 1 over T minus Tc. + +There's an exponent that +shows this, so called, + +critical slowing down. + +Yes? + +AUDIENCE: In principal, +why couldn't you + +have that r becomes negative +if you restrict your range of q + +to be outside of some value +and not go arbitrarily + +close to the origin. + +MEHRAN KARDAR: You could, but +what's the physics of that? + +See. + +AUDIENCE: I'm wondering if +there is or is that not needed. + +MEHRAN KARDAR: No. + +OK, so the physics of that could +be that you have a system that + +has some finite size, [? l. ?] +Then the largest q that you + +could have [? or ?] the smallest +q that you could have would be + +the [? 1/l. ?] So in principal, +for that you can go slightly + +negative. + +You still cannot go too negative +because ultimately this will + +overcome that. + +But again, we are +interested in singularities + +that we kind of know arise +in the limit of [INAUDIBLE]. + +I also recall, there is a +time that we see as diverging + +as r goes to 0. + +Of course, we identified +before a correlation length + +from balancing these two terms, +and the correlation length + +is square root of K over r, +which is again proportional + +to T minus Tc and diverges +with a square root singularity. + +So we can see that this +tao max is actually related + +to the psi squared over Nu K. + +And it is also +related towards this. + +We can see that our tao of +q, basically, if q is large + +such that qc is larger than +1 and the characteristic time + +is going to be 1 over [? nu ?] K +times the inverse of q squared. + +And the inverse of q is +something like a wavelength. + +Whereas, ultimately, this +saturates for qc what is less + +than 1 [? long ?] wavelengths +to c squared over [? nu ?] K. + +So basically you see +things at very short range, + +at length scales that are +much less than the correlation + +length of the system, that +the characteristic time will + +depend on the length scale that +you are looking at squared. + +Now you have seen times +scaling as length squared + +from diffusion, so +essentially this + +is some kind of a +manifestation of diffusion, + +but as you perturb the system, +let's say at short distances, + +there's some equilibrium system. + +Let's say we do some +perturbation to it + +at some point, and +that perturbation + +will start to expand +diffusively until it reaches + +the size of the correlation +length, at which point + +it stops because essentially +correlation length is + +an individual block that doesn't +know about individual blocks, + +so the influence does not last. + +So quite generally, +what you find-- + +so we solved the +linearized version + +of the Landau-Ginzburg +model, but we + +know that, say, the critical +behaviors for the divergence + +of the correlation length +that is predicted here + +is not correct in +three dimensions, + +things get modified. + +So these kind of exponents +that come from diffusion also + +gets modified. + +And quite generally, you +find that the relaxation time + +of a mode of wavelength q +is going to behave something + +like wavelength, +which is 1 over q, + +rather than squared +as some exponent z. + +And then there is some +function of the product + +of the wavelength +you are looking at + +and the correlation length +so that you will cross over + +from one behavior +to another behavior + +as you are looking +at length scales that + +are smaller than the +correlation length + +or larger than the +correlation length. + +And to get what +this exponent z is, + +you have to do study +of the nonlinear model + +in the same sense +that, in order to get + +the correction to the +exponent [? nu ?], + +we had to do epsilon expansion. + +You have to do +something similar, + +and you'll fine that +at higher changes, + +it goes like some correction +that does not actually + +start at order of epsilon but +at order of epsilon squared. + +But there's essentially +some modification + +of the qualitative +behavior that we + +can ascribe to the fusion +of independent modes + +exists quite generally +and universal exponents + +different from [? to ?] +will emerge from that. + +Now it turns out that this +is not the end of the story + +because we have seen +that the same probability + +distribution can describe +a lot of different systems. + +Let's say the focus on +the case of n equals to 1. + +So then this Landau-Ginzburg +that I described + +for you can describe, +let's say, the Ising model, + +which describes +magnetizations that lie + +along the particular direction. + +So that it can also describe +liquid gas phenomena + +where the order parameter is +the difference in density, + +if you like, between +the liquid and the gas. + +Yet another example +that it describes + +is the mixing of an alloy. + +So let's, for example, imagine +brass that has a composition + +x that goes between 0 and 1. + +On one end, let's say +you have entirely copper + +and on the other and +you have entirely zinc. + +And so this is how you +make brass as an alloy. + +And what my other axis +is is the temperature. + +What you find is that there +is some kind of phase diagram + +such that you get a nice +mixture of copper and zinc + +only if you are at +high temperatures, + +whereas if you are +at low temperature, + +you basically will +separate into chunks + +that are rich copper and +chunks that are rich in zinc. + +And you'll have a +critical demixing + +point, which has exactly the +same properties as the Ising + +model. + +For example, this curve +will be characterized + +with an exponent +beta, which would + +be the beta of the Ising mode. + +And in particular, if I +were to take someplace + +in the vicinity of this and +try to write down a probability + +distribution, that +probability distribution + +would be exactly what +I have over there where + +m is, let's say, the difference +between the two types of alloys + +that I have compared to +each other over here. + +So this is related to 2x minus +1 or something like that. + +So as you go across your piece +of material close to here, + +there will be +compositional variations + +that are described by that. + +So the question is, I know +exactly what the probability + +distribution is for this system +to be an equilibrium given + +this choice of m. + +Again, with some set of +parameters, R, U, et cetera. + +The question is-- is the +dynamics again described + +by the same equation? + +And the answer is no. + +The same probability +of distribution + +can describe-- or +can be obtained + +with very different dynamics. + +And in particular, +what is happening + +in the system is that, if +I integrate this quantity m + +across the system, I will +get the total number of 1 + +minus the other, which +is what is given to you, + +and it does not change +as a function of time. + +d by dt of this quantity is 0. + +It cannot change. + +OK. + +Whereas the equation that +I have written over here, + +in principle, locally, I +can, by adding the noise + +or by bringing things +from the neighborhood, + +I can change the value of m. + +I cannot do that. + +So this process of the +relaxation that would go + +on in data graphs cannot be +described by the time dependent + +on the Landau-Ginzburg +equation because you have this + +conservation here. + +OK. + +So what should we do? + +Well, when things are +conserved, like, say, + +as the gas particles +move in this fluid, + +and if I'm interested in +the number of particles + +in some cube, then the +change in the number + +of particles in some +cube in this room + +is related to the gradient +of the current that + +goes into that place. + +So the appropriate way of +writing an equation that + +describes, let's say, the +magnetization changing + +as a function of time. + +Given that you have +a conservation, + +though, is to write it +as minus the gradient + +of some kind of a current. + +So this j is some +kind of a current, + +and these would be vectors. + +This is a current +of the particles + +moving into the system. + +Now, in systems that +are dissipative, + +currents are related to the +gradient of some density + +through the diffusion +constant, et cetera. + +So it kind of makes sense to +imagine that this current is + +the gradient of something that +is trying-- or more precisely, + +minus the gradient +of something that + +tries to bring the system +to be, more or less, + +in its equilibrium state. + +Equilibrium state, as we said, +is determined by this data H, + +and we want to push +it in that direction. + +So we put our data +H by dm over here, + +and we put some kind +of a U over here. + +Of course, I would +have to add some kind + +of a conserved +random current also, + +which is the analog of +this non-conserved noise + +that I add over initially. + +OK. + +Now, the conservative version +of the equation, you can see, + +you have two more +derivatives with respect + +to what we had before. + +And so once I-- OK. + +So if we do something like +this, dm by dt is mu C. + +And then I would +have [INAUDIBLE] + +plus of R, rather +than by itself. + +Actually, it would be the plus +then of something like R m + +plus 4 U m cubed, and so forth. + +And we are going to +ignore this kind of term. + +And then there would +be high order terms + +that would show up minus +k the fourth derivative, + +and so forth. + +And then there may be some +kind of a conserved noise + +that I have to put outside. + +OK. + +So when I fully transform +this equation, what do I get? + +I will get that dm by dt is-- +let's say in the full space, + +until there is a +function of qnt is minus + +U C. Because of this plus, then +there's an additional factor + +of q squared. + +And then I have R +plus kq squared plus L + +cubed to the fourth, et cetera. + +And then I will have a +fully transformed version + +of this conserved noise. + +OK. + +You can see that the difference +between this equation + +and the previous equation is +that all of the relaxation + +times will have an additional +factor of q squared. + +And so eventually, this shortest +relaxation time actually + +will glow like the size +of the system squared. + +Whereas previously, +it was saturated + +at the correlation length. + +And because you will +have this conservation, + +though, you have to +rearrange a lot of particles + +keeping their numbers constant. + +You have a much harder time +of relaxing the system. + +All of the relaxation +times, as we see, + +grow correspondingly +and become higher. + +OK. + +So indeed, for this class, one +can show that z starts with 4, + +and then there +will be corrections + +that would modify that. + +So the-- yes? + +AUDIENCE: How do we +define or how do we + +do a realization of the +conserved noise, conserved + +current-- conserved +noise in the room? + +MEHRAN KARDAR: OK. + +AUDIENCE: So it has some +kind of like correlation-- + +self-correlation +properties, I suppose, + +because, if current +flowing out of some region, + +doesn't it want to go in? + +MEHRAN KARDAR: If +I go back here, + +I have a good idea of what is +happening because all I need, + +in order to ensure conservation, +is that the m by dt + +is the gradient of something. + +AUDIENCE: OK. + +MEHRAN KARDAR: So I can put +whatever I want over here. + +AUDIENCE: So if it's a scalar +or an [INAUDIBLE] field? + +MEHRAN KARDAR: Yes. + +As long as it is sitting +under the gradient-- + +AUDIENCE: OK. + +MEHRAN KARDAR: --it will be OK, +which means this quantity here + +that I'm calling a to +z has a gradient in it. + +And if you wait for +about five minutes, + +we'll show that, because +of that in full space, + +rather than having-- +well, I'll describe + +the difference between +non-conserved and conserved + +noise in fully space. + +It's much easier. + +OK. + +So actually, as far as what I +have discussed so far, which + +is relaxation, I don't +really need the noise + +because I can forget the noise. + +And all I have +said-- and I forgot + +the n tilde-- is that I +have a linear equation that + +relaxes your variable to 0. + +I can immediately read +off for the correlation, + +then this-- a correlation times +what I need the noise for it + +so that, ultimately, I don't go +to the medium is the potential, + +but I go to this +pro-rated distribution. + +So let's see what we have to +do in order to achieve that. + +For simplicity, let's +take this equation. + +Although I can take the +corresponding one for that. + +And let's calculate-- because +of the presence of this noise, + +if I run the same system +at different times, + +I will have different +realizations of the noise + +than if I had run many +versions of the system because + +of the realizations of noise. + +It's quantity and tilde +would be different. + +It would satisfy some kind +of a pro-rated distribution. + +So what I want to do is +to calculate averages, + +such as the average of m tilde. + +Let's say, q1 at time T +with m tilde q2 at time t. + +And you can see already +from this equation + +that, if I forget the part +that comes from the noise, + +whatever initial +condition that I have + +will eventually decay to 0. + +So the thing that +agitates and gives + +some kind of a randomness to +this really comes from this. + +So let's imagine +that we have looked + +at times that are +sufficiently long so + +that the influence of +the initial condition + +has died down. + +I don't want to +write the other term. + +I could do it, but it's kind +of boring to include it. + +So let's forget that and +focus on the integral. + +0 to t. + +Now, if I multiply two +of these quantities, + +I will have two +integrals over t prime. + +All right. + +Each one of them would decay +with the corresponding tau + +of q. + +In one case, tau of q1. + +In the other case, tau of q2. + +Coming from these things. + +And the noise, q1 at time +to 1 prime, and noise q2 + +at time [? t2 prime. ?] + +OK. + +Now if I average over +the noise, then I + +have to do an average over here. + +OK. + +Now, one thing that I forgot to +mention right at the beginning + +is that, of course, +the average of this + +we are going to set to 0. + +It's the very least +that is important. + +Right? + +So if I do that, +clearly, the average + +of one of these in +full space would + +be 0 also because the full q is +related to the real space delta + +just by an integral. + +So if the average of +the integral is 0, + +the average of this is 0. + +So it turns out that, when +you look at the average of two + +of them-- and it's a +very simple exercise + +to just rewrite these things +in terms of 8 of x and t. + +8 of x and t applied +average that you have. + +And we find that the things that +are uncorrelated in real space + +also are uncoordinated +in full space. + +And so the variance +of this quantity + +is 2d delta 1 prime +minus [? d2 prime. ?] + +And then you have the analog +of the function in full space, + +which always carries the +solution of a factor of 2 pi + +to the d. + +And it becomes a sum +of the q's, as we've + +seen many times before. + +OK. + +So because of this +delta function, + +this delta integral +becomes one integral. + +So I have the integral 0 to t. + +The 2t prime I can +write as just 1t prime, + +and these two factors +merge into one. + +It comes into minus t minus +t prime over tau of q, + +except that I get +multiplied by a factor 2 + +since I have two of them. + +And outside of the integral, +I will have this factor of 2d, + +and then 2 pi to the d delta +function with 1 plus 2. + +OK. + +Now, we are really +interested-- and I already + +kind of hinted at +that in the limit + +where time becomes very large. + +In the limit, where time +becomes a very large, + +essentially, I need to calculate +the limit of this integral + +as time becomes very large. + +And as time grows +to very large, this + +is just the integral +from 0 to infinity. + +And the integral is going +to give me 2 over tau of q. + +Essentially, you can see that +integrating at the upper end + +will give me just 0. + +Integrating at the +smaller end, it + +will be exponentially +small as it + +goes to infinity as a +factor of 2 over tau. + +OK. + +Yes? + +AUDIENCE: Are you +assuming or-- yeah. + +Are you assuming that +tau of q is even in q + +to be able to combine to-- + +MEHRAN KARDAR: Yes. + +AUDIENCE: --2 tau? + +So-- OK. + +MEHRAN KARDAR: I'm thinking +of the tau of q's that we've + +calculated over here. + +AUDIENCE: OK. + +MEHRAN KARDAR: OK. + +Yes? + +AUDIENCE: The e +times the [INAUDIBLE] + +do the equation of something? + +Right? + +MEHRAN KARDAR: At this stage, I +am focusing on this expression + +over here, where a is not. + +But I will come to +that expression also. + +So for the time being, this +d is just the same constant + +as we have over here. + +OK? + +So you can see that +the final answer + +is going to be d +over tau of q 2 pi + +to the d delta +function q1 plus q2. + +And if I use the value of tau +of q that I have, tau of q + +is mu R plus kq squared, +which becomes d over mu R + +plus kq squared and so forth. + +2 pi to the d delta +function q1 plus q2. + +So essentially, if I take this +linearized time dependent line + +of Landau-Ginzburg equation, +run it for a very long time, + +and look at the +correlations of the field, + +I see that the +correlations of the field, + +at the limit of long times, +satisfy this expression. + +Now, what do I know if +I look at the top line + +that I have for the +probability of distribution? + +I can go and express that +probability of distribution + +in full mode. + +In the linear +version, I immediately + +get that the probability +of m tilde of q + +is proportional to a +product over different q's, + +e to the minus R +plus kq squared, + +et cetera, and tilde +of q squared over 2. + +All right. + +So when I look at the +equilibrium linear + +as Landau-Ginzburg, I can +see that, if I calculate + +the average of m of +q1, m of q2, then + +this is an equilibrium average. + +What I would get is 2 pi +to the d delta function + +of q1 plus q2 because, clearly, +the different q's are recovered + +from each other. + +And for the particular value of +q, what I will get is 1 over R + +plus kq squared and so forth. + +Yes? + +AUDIENCE: So isn't the 2 +over tau-- [INAUDIBLE]? + +MEHRAN KARDAR: Yes. + +Over 2. + +Yeah. + +OK. + +OK. + +I changed because I +had 2d cancels the 2. + +I would have to put +here tau of q over 2. + +I had 2d times tau of q over 2. + +So it's d tau. + +And inverse of tau, I +have everything correct. + +OK. + +So if you make an even number +of errors, the answer comes up. + +OK. + +But you can now +compare this expression + +that comes from equilibrium +and this expression that + +comes from the long time +limit of this noisy equation. + +OK So we want to +choose our noise + +so that the stochastic +dynamics gives the same value + +as equilibrium, just like we +did for the case of a Brownian + +particular where you have some +kind of an Einstein equation + +that was relating the strength +of the noise and the mobility. + +And we see that here +all I need to do + +is to ensure that d over +mu should be equal to 1. + +OK. + +Now, the thing is that, +if I am doing this, + +I, in principle, can have a +different noise for each q, + +and compensate by different +mobility for each q. + +And I would get the same answer. + +So in the non-conserved version +of this time dependent dynamics + +that you wrote down, +the d was a constant + +and the mu was a constant. + +Whereas, if you want to get +the same equilibrium result out + +of the conserved dynamics, +you can see that, essentially, + +what we previously had as +mu became something that + +is proportional to q squared. + +So essentially, here, this +becomes mu C q squared. + +So clearly, in order +to get the same answer, + +I have to put my noise to be +proportional to q squared also. + +And we can see that this kind of +conserved noise that I put over + +here achieves that +because, as I said, + +this conserved noise is the +gradient of something, which + +means that, when I go to +fully space, if it be q, + +it will be proportional to q. + +And when I take its +variants, it's variants + +will be proportional +to q squared. + +Anything precisely canceled. + +But you can see +that you also-- this + +had a physical explanation in +terms of a conservation law. + +In principle, you can cook +up all kinds of b of q and mu + +of q. + +As long as this equality is +satisfied, you will have, + +for these linear +stochastic equations, + +the guarantee that you would +always get the same equilibrium + +result. + +Because if you wait +for this dynamics + +to settle down after long times, +you will get to the answer. + +Yes? + +AUDIENCE: I wonder how general +is this result for stochastic + +[INAUDIBLE]? + +MEHRAN KARDAR: OK. + +AUDIENCE: But what I-- + +MEHRAN KARDAR: So +what I showed you + +was with for linearized version, +and the only thing that I + +calculated was the variance. + +And I showed that the +variances were the same. + +And if I have a Gaussian +problem of distribution, + +the variance is +completely categorizable + +with distribution. + +So this is safe. + +But we are truly interested +in the more general + +non-Gaussian probability +of distribution. + +So the question really is-- if +I keep the full non-linearity + +in this story, would +I be able to show + +that the probability +of distribution that + +will be characterized +by all kinds of moments + +eventually has the +same behavior as that. + +AUDIENCE: Mm-hmm. + +MEHRAN KARDAR: And the +answer is, in fact, yes. + +There's a procedure that +relies on converting + +this equation-- sorry. + +One equation that +governs the evolution + +of the full probability +as a function of time. + +Right? + +So basically, I can start +with a an initial probability + +and see how this probability +evolves as a function of time. + +And this is sometimes +called a master equation. + +Sometimes, called a +[INAUDIBLE] equation. + +And we did cover, in fact, +this in-- next spring + +in the statistical +physics and biology, + +we spent some time talking +about these things. + +So you can come back to the +third version of this class. + +And one can ensure that, +with appropriate choice + +of the noise, the asymptotic +solution for this probability + +distribution is +whatever Landau-Ginzburg + +or other probability +distribution + +that you need most. + +AUDIENCE: So is this +true if we assume + +Landau-Ginzburg potential +for how resistant? + +MEHRAN KARDAR: Yes. + +AUDIENCE: OK. + +Maybe this is not a very +good-stated question, + +but is there kind of like +an even more general level? + +MEHRAN KARDAR: I'll +come to that, sure. + +But currently, the way +that I set up the problem + +was that we know some +complicated equilibrium + +force that exist-- form of +the probability that exist. + +And these kinds of +linear-- these kinds + +of stochastic linear +or non-linear evolution + +equations-- generally +called non- [INAUDIBLE] + +equations-- one can show that, +with the appropriate choice + +of the noise, we'll be able +to asymptotically reproduce + +the probability of +distribution that we knew. + +But now, the question +is, of course, you + +don't know the probability +of distribution. + +And I'll say a few +words about that. + +AUDIENCE: OK. + +Thank you. + +MEHRAN KARDAR: Anything else? + +OK. + +So the lesson of this +part is that the field + +of dynamic or critical phenomena +is quite rich, much richer + +than the corresponding +equilibrium critical phenomena + +because the same +equilibrium state can + +be obtained by various +different types of dynamics. + +And I explained to you +just one conservation law, + +but there could be +some combination + +of conservation of energy, +conservation of something. + +So there is a whole listing of +different universality classes + +that people have targeted +for the dynamics. + +But not all of this +was assuming that you + +know what the ultimate answer +is because, in all cases, + +the equations that +we're writing are + +dependent on some kind of a +gradient descent conserved + +or non-conserved around +something that corresponded + +to the log of probability +of distribution + +that we eventually want to put. + +And maybe you don't +know that, and so + +let me give you a particular +example in the context of, + +let's say, surface +interface fluctuations. + +Starting from things that +you know and then building + +to something that +maybe you don't. + +Let's first with the +case of a soap bubble. + +So we take some kind of +a circle or whatever, + +and we put a soap +bubble on top of it. + +And in this case, the +energy of the formation-- + +the cost of the formation +comes from surface tension. + +And let's say, the +cost of the deformation + +is the changing area +times some sigma. + +So I neglect the +contribution that + +comes from the flat surface, +and see if I make a deformation. + +If I make a deformation, I have +changed the area of the spin. + +So there is a cost that is +proportion to the surface + +tension times the +change in area. + +Change in area locally +is the square root of 1 + +plus the gradient +of a height profile. + +So what I can do is I can define +at each point on the surface + +how much it has changed its +height from being perfectly + +flat. + +So h equals to 0 is flat. + +Local area is the integral +dx dy of square root of 1 + +plus gradient of h +squared, minus 1. + +That corresponds to the flat. + +And so then you expand that. + +The first term is going to +be the integral gradient of h + +squared. + +So this is the analog of +what we had over there, only + +the first term. + +So you would say that the +equation that you would write + +down for this would be +all to some constant mu + +proportional to the +variations of this, + +which will give me something +like sigma Laplacian of h. + +But because of the particles +from the air constantly + +bombarding the +surface, there will + +be some noise that +depends on where + +you are on the surface in time. + +And this is the +non-conserved version. + +And you can from +this very quickly get + +that the expectation value +of h tilde of q squared + +is going to be proportional +to something like D + +over mu sigma q squared, +because of this q squared. + +And if you ask how +much fluctuations you + +have in real space-- +so that typical scale + +of the fluctuations +in real space-- + +will come from integrating +1 over q squared. + +And it's going to be +our usual things that + +have this logarithmic +dependence, so there will + +be something that ultimately +will go logarithmically + +with the size of the system. + +The constant of +proportionality will be + +proportional to kt over sigma. + +So you have to choose your D +and mu to correspond to this. + +But basically, a soap +film, as an example + +of all kinds of Goldstone +mode-like things + +that we have seen. + +It's a 2-dimensional entity. + +We will have logarithmic +fluctuations-- not very big, + +but ultimately, at +large enough distances, + +it will have fluctuations. + +So that was non-conserved. + +I can imagine that, +rather than this, + +I have the case of +a surface of a pool. + +So here I have some +depth of water, + +and then there's the surface +of the pool of water. + +And the difference between this +case and the previous case-- + +both of them can be described +by a height function. + +The difference is that +if I ignore evaporation + +and condensation, the +total mass of water + +is going to be conserved. + +So I would need to have divided +t of the integral dx d qx + +h of x and t to be 0. + +So this would go into +the conserved variety. + +And while, if I create a +ripple on the surface of this + +compared to the surface of +that, the relaxation time + +through this +dissipative dynamics + +would be much longer in this +case as opposed to that case. + +Ultimately, if I wait +sufficiently long time, + +both of them would have +exactly the same fluctuations. + +That is, you would go +logarithmically with the length + +scale over which [INAUDIBLE]. + +OK, so now let's look at +another system that fluctuates. + +And I don't know what +the final answer is. + +That was the question, +maybe, that you asked. + +The example that I will +give is the following-- + +so suppose that +you have a surface. + +And then you have a +rain of sticky materials + +that falls down on top of it. + +So this material will come down. + +You'll have something like this. + +And then as time +goes on, there will + +be more material that will come, +more material that will come, + +more material that will come. + +So there, because the particles +are raining down randomly + +at different points, there +will be a stochastic process + +that is going on. + +So you can try to +characterize the system + +in terms of a height that +changes as a function of t + +and as a function of position. + +And there could be all kinds +of microscopic things going on, + +like maybe these +are particles that + +are representing some kind +of a deposition process. + +And then they come, they +stick in a particular way. + +Maybe they can slide +on the surface. + +We can imagine all kinds of +microscopic degrees of freedom + +and things that we can put. + +But you say, well, can +I change my perspective, + +and try to describe the +system the same way that we + +did for the case of +coarse grading and going + +from without the +microscopic details + +to describe the phenomenological +Landau-Ginzburg equation? + +And so you say, OK, there +is a height that is growing. + +And what I will write +down is an equation + +that is very similar +to the equations + +that I had written before. + +Now I'm going to follow +the same kind of reasoning + +that we did in the construction +of this Landau-Ginzburg model, + +is we said that this weight +is going to depend on all + +kinds of things that +relate to this height + +that I don't quite know. + +So let's imagine that there +is some kind of a function + +of the height itself. + +And potentially, just +like we did over there, + +the gradient of the height, +five derivatives of the height, + +et cetera. + +And then I will start to +make an expansion of this + +in the same spirit that I did +for the Landau-Ginzburg Model, + +except that when I was doing +the Landau-Ginzburg Model, + +I was doing the expansion +at the level of looking + +at the probability distribution +and the log of the probability. + +Here I'm making the expansion +at the level of an equation that + +governs the dynamics. + +Of course, in this +particular system, + +that's not the end of story, +because the change in height + +is also governed by this random +addition of the particles. + +So there is some +function that changes + +as a function of +position and time, + +depending on whether, +at that time, + +a particle was dropped down. + +I can always take +the average of this + +to be 0, and put that average +into the expansion of this + +starting from a constant. + +Basically, if I just +have a single point + +and I randomly drop particles +at that single point, + +there will be an +average growth velocity, + +an average addition +to the height, + +that averages over here. + +But there will be fluctuations +that are going [INAUDIBLE]. + +OK but the constant +is the first term + +in an expansion such as this. + +And you can start thinking, +OK, what next order? + +Can I put something +like alpha h? + +Potentially-- depends +on your system-- + +but if the system is invariant +whether you started from here + +or whether you started from +there-- something like gravity, + +for example, is not +important-- you say, OK, + +I cannot have any function of +h if my dynamics will proceed + +exactly the same way if I +were to translate this surface + +to some further up +or further down. + +If I see that there's no change +in future dynamics on average, + +then the dynamic +cannot depend on this. + +OK, so we've got rid of that. + +And any function +of h-- can I put + +something that is +proportional to gradient of h? + +Maybe for something I can, +but for h itself I cannot, + +because h is a scalar gradient. + +If h is a vector, I +can't set something + +that is a scalar equal to a +vector, so I can't have this. + +Yes? + +AUDIENCE: Couldn't +you, in principle, + +make your constant term in +front of the gradient also + +a vector and [INAUDIBLE]? + +MEHRAN KARDAR: You could. + +So there's a whole set +of different systems + +that you can be thinking about. + +Right now, I want to focus +on the simplest system, which + +is a scalar field, so +that my equation can + +be as simple as +possible, but still we + +will see it has +sufficient complication. + +So you can see that +if I don't have them, + +the next order term +that I can have + +would be something +like a Laplacian. + +So this kind of diffusion +equation, you can see, + +has to emerge as a low-order +expansion of something + +like this. + +And this is the ubiquity of the +diffusion equation appearing + +all over the place. + +And then you could +have terms that + +would be of the order of +the fourth derivative, + +and so forth. + +There's nothing wrong with that. + +And then, if you +think about it, you'll + +see that there is one +interesting possibility that + +is not allowed for +that system, but is + +allowed for this system, which +is something that is a scalar. + +It's the gradient of h squared. + +Now I could not have added this +term for the case of the soap + +bubble for the +following reason-- + +that if I reverse the +soap bubble so that h + +becomes minus h, the dynamics +would proceed exactly + +as before. + +So the soap bubble has a +symmetry of h going to minus h, + +and so that symmetry should +be preserved in the equation. + +This term breaks that symmetry +because the left-hand side + +is odd in h, whereas the +right-hand side of this term + +would be even in h. + +But for the case of the growing +surface-- and you've seen + +things that are growing. + +And typically, if I +give you something + +that has grown like the +tree trunk, for example, + +and if I take the +picture of a part of it, + +and you don't see where the +center is, where the end is, + +you can immediately +tell from the way + +that the shape of this +object is, that it is growing + +in some particular direction. + +So for growth systems, that +symmetry does not exist. + +You are allowed to have +this term, and so forth. + +Now the interesting +thing about this term + +is that there is no beta +h that you can write down + +that is local-- some +function of h such + +that if you take a functional +derivative with respect to h, + +it will reproduce that +term-- just does not exist. + +So you can see that +somehow immediately, + +as soon as we liberate ourselves +from writing equations that + +came from functional +derivative of something, + +but potentially have +physical significance, + +we can write down new terms. + +So this is actually-- +also, you can do + +this, even for two particles. + +A potential v of x1 and x2 will +have some kind of derivatives. + +But if you write +dynamical equations, + +there are dynamical +equations that + +allow you to rotate +1 x from x1 to x2. + +That kind of term +will never come + +from taking the derivative. + +So fine. + +So this is a candidate +equation that + +is obtained in this context-- +something that is grown. + +We say we are not +interested in it's + +coming from some +underlying weight, + +but presumably, +this system still, + +if I look at it at +long times, will + +have some kind of fluctuations. + +All the fluctuations of +this growing surface, + +like the fluctuations +of the soap bubble, + +and they have this +logarithmic dependence. + +You have a question? + +AUDIENCE: So why doesn't that +term-- what if I put in h times + +that term that we want +to appear and then I + +vary with respect to h? + +A term like what we want to pop +out together with other terms? + +MEHRAN KARDAR: Yeah, +but those other terms, + +what do you want +to do with them? + +AUDIENCE: Well, maybe they're +not acceptable [INAUDIBLE]? + +MEHRAN KARDAR: So you're +saying why not have a term that + +is h gradient of h squared? + +Functional derivative of that +is gradient of h squared. + +And then you have a term +that is h Laplacian-- it's + +a gradient of, +sorry, gradient of h. + +And then you expand this. + +Among the terms that +you would generate + +would be a term that +is h, a Laplacian of h. + +This term violates +this condition + +that we had over here. + +And you cannot separate +this term from that term. + +So what you +describe, you already + +see at the level over here. + +It violates translation of +symmetry in [? nature ?]. + +And you can play around +with other functions. + +You come to the same conclusion. + +OK, so the question is, well, +you added some term here. + +If I look at this surface +that has grown at large time, + +does it have the same +fluctuations as we had before? + +So a simple way +to ascertain that + +is to do the same kind +of dimensional analysis + +which, for the Landau-Ginzburg, +was a prelude to doing + +renormalization. + +So we did things like +epsilon expansion, et cetera. + +But to calculate that there +was a critical dimension of 4, + +all we needed to do +was to rescale x and m, + +and we would +immediately see that mu + +goes to mu, b to the 4 +minus D or something-- + +D minus 4, for example. + +So we can do the +same thing here. + +We can always move +to a frame that + +is moving with the +average velocity, + +so that we are focusing +on the fluctuations. + +So we can basically +ignore this term. + +I'm going to rescale +x by a factor of b. + +I'm going to rescale time by +a factor of b to something + +to the z. + +And this z is kind +of indicative of what + +we've seen before-- that somehow +in these dynamical phenomena, + +the scaling of time and space +are related to some exponent. + +But there's also +an exponent that + +characterizes how +the fluctuations in h + +grow if I look at systems +that are larger and larger. + +In particular, if I had +solved that equation, + +rather than for a soap +bubble in two dimensions, + +for a line-- for a string that +I was pulling so that I had + +line tension-- the +one-dimensional version of it, + +the one-dimensional version of +an integral of 1 over q squared + +would be something +that would grow + +with the size of the system. + +So there I would have a +chi of 1/2, for example, + +in one dimension. + +So this is the general thing. + +And then I would say that +the first equation, dhy dt, + +gets a factor of +b to the chi minus + +z, because h scaled +by a factor of chi, + +t scaled by a factor of z, +the term sigma Laplacian of h + +gets a factor of b +to the chi minus 2 + +from the two derivatives here-- +sorry, the z and the 2 look + +kind of the same. + +This is a z. + +This is a 2. + +And then the term +that is proportional + +to this non-linearity that +I wrote down-- actually, it + +is very easy, maybe worthwhile, +to show that sigma to the 4th + +goes with a factor of +b to the chi minus 4. + +It is always down by a factor of +two scalings in b with respect + +to a Laplacian-- the +same reason that when + +we were doing the +Landau-Ginzburg. + +We could terminate the series +at order of gradient squared, + +because higher-order +derivatives were irrelevant. + +They were scaling to 0. + +But this term grows +like b to the 2 chi, + +because it's h squared, minus 2, +because there's two gradients. + +Now thinking about +the scaling of eta + +takes a little bit of thought, +because what we have-- we + +said that the average +of eta goes to 0. + +The average of eta at +two different locations + +and two different times-- +it is these particles that + +are raining down-- +they're uncorrelated + +at different times. + +They're uncorrelated +at different positions. + +There's some kind +of variance here, + +but that's not important to us. + +If I rescale t by a factor +of b, delta of bt-- sorry, + +if I scale t by a factor of b +to the z, delta of b to the zx + +will get a factor +of b to the minus z. + +This will get a factor +of b to the minus d. + +But the noise, eta, +is half of that. + +So what I will have is b to +the minus z plus d over 2 times + +eta on the rescalings +that I have indicated. + +I get rid of this term. + +So this-- divide by +b to the chi minus z. + +So then this becomes bh y dt +is sigma b to the z minus 2. + +Maybe I'll write it in +red-- b to the z minus 2. + +This becomes sigma to the +4, b to the z minus 4. + +And then lambda over 2. + +This is Laplacian of h. + +This, for derivative of +h, this is Laplacian of h. + +This term becomes b to the chi +plus z minus 2, gradient of h + +squared. + +And the final term becomes b to +the chi minus d minus z over 2. + +AUDIENCE: [INAUDIBLE]? + +MEHRAN KARDAR: b to the +minus chi-- you're right. + +And then, actually, this I-- no? + +Minus chi minus d over 2 +minus d over 2 [INAUDIBLE], + +That's fine. + +So I can make this +equation to be invariant. + +So I want to find +out what happens + +to this system if I find +some kind of an equation, + +or some kind of behavior +that is scale invariant. + +You can see that immediately, +my choice for the first term + +has to be z equals to 2. + +So basically, it +says that as long + +as you're governed by +something that is diffusive, + +so that when you go to Fourier +space, you have q squared, + +your relaxation times +are going to have + +this diffusive character, +where time is distance squared. + +Actually, you can see that +immediately from the equation + +that this diffusion time +goes like distance squared. + +So this is just a +statement of that. + +Now, it is the noise that +causes the fluctuations. + +And if I haven't made +some simple error, + +you will find that the +coefficient of the noise term + +becomes scale invariant, +provided that I choose it + +to be z minus d over 2 for chi. + +And since my z was +2, I'm forced to have + +chi to be 2 minus d over 2. + +And let's see if it +makes sense to us. + +So if I have a surface such +as the case of the soap bubble + +in two dimensions, chi is 0. + +And 0 is actually +this limiting case + +that would also be a logarithm. + +If I go to the case of d equals +to 1-- like pulling a line + +and having the line fluctuate-- +then I have 2 minus 1 + +over 2, which is +1/2, which means + +that, because of +thermal fluctuations, + +this line will look +like it a random walk. + +You go a distance x. + +The fluctuations +in height will go + +like the square root of that. + +OK? + +So all of that is fine. + +You would have done +exactly the same answer + +if you had just gotten a +kind of scaling such as this + +for the case of +the Gaussian Model + +without the nonlinearities. + +But for the Gaussian +Model with nonlinearities, + +we could also then estimate +whether the nonlinearity u + +is relevant. + +So here we see that the +coefficient of our nonlinearity + +is lambda, is +governed by something + +that is chi plus z minus 2. + +And our chi is 2 minus z over 2. + +z minus 2 is 0. + +So whether or not this +nonlinearity is relevant, + +we can see depends +on whether you're + +above or below two dimensions. + +So when you are +below two dimensions, + +this nonlinearity is relevant. + +And you will certainly +have different types + +of scaling phenomena +then what you + +predict by the case of the +diffusion equation plus noise. + +Of course, the +interesting case is + +when you are at the +marginal dimension of 2. + +Now, in terms of when you do +proper renormalization group + +with this nonlinearity, +you will find that, + +unlike the nonlinearity of +the Landau-Ginzburg, which + +is marginally irrelevant +in four dimensions. + +du by dl was minus u +squared, this lambda + +is marginally relevant. + +d lambda by dl is proportional +to plus lambda squared. + +It is relevant marginality-- +marginally relevant. + +And actually, the +epsilon expansion + +gives you no information about +what's happening in the system. + +So people have then done +numerical simulations. + +And they find that there +is a roughness that + +is characterized by an exponent, +say something like 0.4. + +So that when you look at +some surface that is grown, + +is much, much rougher than +the surface of a soap bubble + +or what's happening on +the surface of the pond. + +And the key to all of this is +that we wrote down equations + +on the basis of +this generalization + +on symmetry that we had +learned, now applied + +to this dynamical +system, did an expansion, + +found one first term. + +And we found it to be relevant. + +And is actually not +that often that you + +find something that is +relevant, because then it + +is a reason to celebrate. + +Because most of the time, +things are irrelevant, + +and you end up with boring +diffusion equations. + +So find something +that is relevant. + +And that's my last +message to you. \ No newline at end of file diff --git a/Q-nk311H-Fw.txt b/Q-nk311H-Fw.txt new file mode 100644 index 0000000000000000000000000000000000000000..e3ee3dc9f3602c04c78ba66b925606d747d4141c --- /dev/null +++ b/Q-nk311H-Fw.txt @@ -0,0 +1,1291 @@ +align:start position:0% + +visualization is a crucial step for + + align:start position:0% +visualization is a crucial step for + + + align:start position:0% +visualization is a crucial step for +initial data exploration + + align:start position:0% +initial data exploration + + + align:start position:0% +initial data exploration +it helps us discern relationships + + align:start position:0% +it helps us discern relationships + + + align:start position:0% +it helps us discern relationships +patterns and outliers this video will + + align:start position:0% +patterns and outliers this video will + + + align:start position:0% +patterns and outliers this video will +give us a starting point on how to make + + align:start position:0% +give us a starting point on how to make + + + align:start position:0% +give us a starting point on how to make +plots on our but more advanced and way + + align:start position:0% +plots on our but more advanced and way + + + align:start position:0% +plots on our but more advanced and way +cooler visualization tips will be given + + align:start position:0% +cooler visualization tips will be given + + + align:start position:0% +cooler visualization tips will be given +in week eight of this class let us first + + align:start position:0% +in week eight of this class let us first + + + align:start position:0% +in week eight of this class let us first +create a scatter plot with protein on + + align:start position:0% +create a scatter plot with protein on + + + align:start position:0% +create a scatter plot with protein on +the x-axis and fat on the y-axis to do + + align:start position:0% +the x-axis and fat on the y-axis to do + + + align:start position:0% +the x-axis and fat on the y-axis to do +this we can use the plot function in R + + align:start position:0% +this we can use the plot function in R + + + align:start position:0% +this we can use the plot function in R +and give it as a first input the protein + + align:start position:0% +and give it as a first input the protein + + + align:start position:0% +and give it as a first input the protein +factor on the x-axis and as a second + + align:start position:0% +factor on the x-axis and as a second + + + align:start position:0% +factor on the x-axis and as a second +input the total fat vector on the y-axis + + align:start position:0% +input the total fat vector on the y-axis + + + align:start position:0% +input the total fat vector on the y-axis +and now pressing enter in new window + + align:start position:0% +and now pressing enter in new window + + + align:start position:0% +and now pressing enter in new window +pops up if you are on a PC the new + + align:start position:0% +pops up if you are on a PC the new + + + align:start position:0% +pops up if you are on a PC the new +window is called our graphics and if you + + align:start position:0% +window is called our graphics and if you + + + align:start position:0% +window is called our graphics and if you +are on a Mac it is called quartz the + + align:start position:0% +are on a Mac it is called quartz the + + + align:start position:0% +are on a Mac it is called quartz the +plot has a very interesting triangular + + align:start position:0% +plot has a very interesting triangular + + + align:start position:0% +plot has a very interesting triangular +shape it looks like foods that are + + align:start position:0% +shape it looks like foods that are + + + align:start position:0% +shape it looks like foods that are +higher in protein are typically lower in + + align:start position:0% +higher in protein are typically lower in + + + align:start position:0% +higher in protein are typically lower in +fat and vice versa now looking at the + + align:start position:0% +fat and vice versa now looking at the + + + align:start position:0% +fat and vice versa now looking at the +aesthetics of the graph we realize the + + align:start position:0% +aesthetics of the graph we realize the + + + align:start position:0% +aesthetics of the graph we realize the +argives default names for the x axis and + + align:start position:0% +argives default names for the x axis and + + + align:start position:0% +argives default names for the x axis and +the y axis using the vector dollar + + align:start position:0% +the y axis using the vector dollar + + + align:start position:0% +the y axis using the vector dollar +notation we can modify these labels by + + align:start position:0% +notation we can modify these labels by + + + align:start position:0% +notation we can modify these labels by +adding more arguments to the plot + + align:start position:0% +adding more arguments to the plot + + + align:start position:0% +adding more arguments to the plot +function to go back to the our console + + align:start position:0% +function to go back to the our console + + + align:start position:0% +function to go back to the our console +you can simply switch windows using the + + align:start position:0% +you can simply switch windows using the + + + align:start position:0% +you can simply switch windows using the +ctrl tab if you are on a Windows machine + + align:start position:0% +ctrl tab if you are on a Windows machine + + + align:start position:0% +ctrl tab if you are on a Windows machine +on a Mac the windows are not overlaid by + + align:start position:0% +on a Mac the windows are not overlaid by + + + align:start position:0% +on a Mac the windows are not overlaid by +default so accessing the console should + + align:start position:0% +default so accessing the console should + + + align:start position:0% +default so accessing the console should +be easy ok now let's use the up arrow to + + align:start position:0% +be easy ok now let's use the up arrow to + + + align:start position:0% +be easy ok now let's use the up arrow to +go back to our plot function and at the + + align:start position:0% +go back to our plot function and at the + + + align:start position:0% +go back to our plot function and at the +argument X lab equal protein and that + + align:start position:0% +argument X lab equal protein and that + + + align:start position:0% +argument X lab equal protein and that +gives us the label of the x axis then y + + align:start position:0% +gives us the label of the x axis then y + + + align:start position:0% +gives us the label of the x axis then y +iLab equals fat and this gives us the + + align:start position:0% +iLab equals fat and this gives us the + + + align:start position:0% +iLab equals fat and this gives us the +label to the y axis and let's add a + + align:start position:0% +label to the y axis and let's add a + + + align:start position:0% +label to the y axis and let's add a +title to the plot using the argument + + align:start position:0% +title to the plot using the argument + + + align:start position:0% +title to the plot using the argument +main say the title is protein versus fat + + align:start position:0% +main say the title is protein versus fat + + + align:start position:0% +main say the title is protein versus fat +and let's change the color to red and + + align:start position:0% +and let's change the color to red and + + + align:start position:0% +and let's change the color to red and +remember to put quotation marks around + + align:start position:0% +remember to put quotation marks around + + + align:start position:0% +remember to put quotation marks around +the values of all these arguments and + + align:start position:0% +the values of all these arguments and + + + align:start position:0% +the values of all these arguments and +now pressing enter going back to the + + align:start position:0% +now pressing enter going back to the + + + align:start position:0% +now pressing enter going back to the +graphics window we see that our made all + + align:start position:0% +graphics window we see that our made all + + + align:start position:0% +graphics window we see that our made all +the modifications we requested another + + align:start position:0% +the modifications we requested another + + + align:start position:0% +the modifications we requested another +way we can visualize our data is by + + align:start position:0% +way we can visualize our data is by + + + align:start position:0% +way we can visualize our data is by +plotting histogram + + align:start position:0% +plotting histogram + + + align:start position:0% +plotting histogram +we can do this using the histogram + + align:start position:0% +we can do this using the histogram + + + align:start position:0% +we can do this using the histogram +function in our but note that this + + align:start position:0% +function in our but note that this + + + align:start position:0% +function in our but note that this +function now only takes one variable as + + align:start position:0% +function now only takes one variable as + + + align:start position:0% +function now only takes one variable as +an input because the y-axis should have + + align:start position:0% +an input because the y-axis should have + + + align:start position:0% +an input because the y-axis should have +the frequencies so let's go back to our + + align:start position:0% +the frequencies so let's go back to our + + + align:start position:0% +the frequencies so let's go back to our +console and create a histogram of + + align:start position:0% +console and create a histogram of + + + align:start position:0% +console and create a histogram of +vitamin C for instance so we're gonna + + align:start position:0% +vitamin C for instance so we're gonna + + + align:start position:0% +vitamin C for instance so we're gonna +use the piston or histogram and then the + + align:start position:0% +use the piston or histogram and then the + + + align:start position:0% +use the piston or histogram and then the +argument that it takes is the vitamin C + + align:start position:0% +argument that it takes is the vitamin C + + + align:start position:0% +argument that it takes is the vitamin C +vector let's label the x-axis as vitamin + + align:start position:0% +vector let's label the x-axis as vitamin + + + align:start position:0% +vector let's label the x-axis as vitamin +C and this is given to us in milligrams + + align:start position:0% +C and this is given to us in milligrams + + + align:start position:0% +C and this is given to us in milligrams +and give it a title say histogram of + + align:start position:0% +and give it a title say histogram of + + + align:start position:0% +and give it a title say histogram of +vitamin C levels hmm even though the + + align:start position:0% +vitamin C levels hmm even though the + + + align:start position:0% +vitamin C levels hmm even though the +maximum vitamin C content is 2,000 + + align:start position:0% +maximum vitamin C content is 2,000 + + + align:start position:0% +maximum vitamin C content is 2,000 +milligrams most of our foods well to be + + align:start position:0% +milligrams most of our foods well to be + + + align:start position:0% +milligrams most of our foods well to be +more precise more than 6,000 of them + + align:start position:0% +more precise more than 6,000 of them + + + align:start position:0% +more precise more than 6,000 of them +have less than 200 milligrams of vitamin + + align:start position:0% +have less than 200 milligrams of vitamin + + + align:start position:0% +have less than 200 milligrams of vitamin +C and the histogram lumps them all + + align:start position:0% +C and the histogram lumps them all + + + align:start position:0% +C and the histogram lumps them all +together in one cell well it would be + + align:start position:0% +together in one cell well it would be + + + align:start position:0% +together in one cell well it would be +nice if we can zoom into this section + + align:start position:0% +nice if we can zoom into this section + + + align:start position:0% +nice if we can zoom into this section +here and get a finer understanding of + + align:start position:0% +here and get a finer understanding of + + + align:start position:0% +here and get a finer understanding of +the data to do this we need to limit the + + align:start position:0% +the data to do this we need to limit the + + + align:start position:0% +the data to do this we need to limit the +x-axis to go from zero to say 100 + + align:start position:0% +x-axis to go from zero to say 100 + + + align:start position:0% +x-axis to go from zero to say 100 +milligrams so let's go back to the + + align:start position:0% +milligrams so let's go back to the + + + align:start position:0% +milligrams so let's go back to the +console and then we're going to add the + + align:start position:0% +console and then we're going to add the + + + align:start position:0% +console and then we're going to add the +argument x lim to limit the x-axis and + + align:start position:0% +argument x lim to limit the x-axis and + + + align:start position:0% +argument x lim to limit the x-axis and +using the combine function or the c + + align:start position:0% +using the combine function or the c + + + align:start position:0% +using the combine function or the c +function we're gonna set the first input + + align:start position:0% +function we're gonna set the first input + + + align:start position:0% +function we're gonna set the first input +to be zero which is the lowest value + + align:start position:0% +to be zero which is the lowest value + + + align:start position:0% +to be zero which is the lowest value +that we want to see on the x-axis and + + align:start position:0% +that we want to see on the x-axis and + + + align:start position:0% +that we want to see on the x-axis and +the second argument is being 100 which + + align:start position:0% +the second argument is being 100 which + + + align:start position:0% +the second argument is being 100 which +is the highest value that we want to see + + align:start position:0% +is the highest value that we want to see + + + align:start position:0% +is the highest value that we want to see +on the x axis and now pressing enter and + + align:start position:0% +on the x axis and now pressing enter and + + + align:start position:0% +on the x axis and now pressing enter and +we can see that our gives us 0 to 100 on + + align:start position:0% +we can see that our gives us 0 to 100 on + + + align:start position:0% +we can see that our gives us 0 to 100 on +the x axis but we only see this one big + + align:start position:0% +the x axis but we only see this one big + + + align:start position:0% +the x axis but we only see this one big +cell it's used that are only zoomed into + + align:start position:0% +cell it's used that are only zoomed into + + + align:start position:0% +cell it's used that are only zoomed into +the area but it didn't break that huge + + align:start position:0% +the area but it didn't break that huge + + + align:start position:0% +the area but it didn't break that huge +cell and this doesn't give us any + + align:start position:0% +cell and this doesn't give us any + + + align:start position:0% +cell and this doesn't give us any +additional information so we really need + + align:start position:0% +additional information so we really need + + + align:start position:0% +additional information so we really need +to break up the cell into smaller pieces + + align:start position:0% +to break up the cell into smaller pieces + + + align:start position:0% +to break up the cell into smaller pieces +and say we want 100 cells and since the + + align:start position:0% +and say we want 100 cells and since the + + + align:start position:0% +and say we want 100 cells and since the +interval goes from 0 to 100 then we + + align:start position:0% +interval goes from 0 to 100 then we + + + align:start position:0% +interval goes from 0 to 100 then we +would expect our to create divisions + + align:start position:0% +would expect our to create divisions + + + align:start position:0% +would expect our to create divisions +that are 1 milligrams in length so let's + + align:start position:0% +that are 1 milligrams in length so let's + + + align:start position:0% +that are 1 milligrams in length so let's +do this let's go back to the console and + + align:start position:0% +do this let's go back to the console and + + + align:start position:0% +do this let's go back to the console and +then we're going to add the argument + + align:start position:0% +then we're going to add the argument + + + align:start position:0% +then we're going to add the argument +rakes equals 100 and this sets the + + align:start position:0% +rakes equals 100 and this sets the + + + align:start position:0% +rakes equals 100 and this sets the +number of cells that we want to see to + + align:start position:0% +number of cells that we want to see to + + + align:start position:0% +number of cells that we want to see to +100 so let's see oh we actually only see + + align:start position:0% +100 so let's see oh we actually only see + + + align:start position:0% +100 so let's see oh we actually only see +5 cells and each cell is 20 milligrams + + align:start position:0% +5 cells and each cell is 20 milligrams + + + align:start position:0% +5 cells and each cell is 20 milligrams +long well what happened we were + + align:start position:0% +long well what happened we were + + + align:start position:0% +long well what happened we were +expecting 100 cells I'll remember that + + align:start position:0% +expecting 100 cells I'll remember that + + + align:start position:0% +expecting 100 cells I'll remember that +the histogram originally went far beyond + + align:start position:0% +the histogram originally went far beyond + + + align:start position:0% +the histogram originally went far beyond +100 milligrams the maximum was 2,000 + + align:start position:0% +100 milligrams the maximum was 2,000 + + + align:start position:0% +100 milligrams the maximum was 2,000 +milligrams and now if we were to divide + + align:start position:0% +milligrams and now if we were to divide + + + align:start position:0% +milligrams and now if we were to divide +the original interval from zero to 2,000 + + align:start position:0% +the original interval from zero to 2,000 + + + align:start position:0% +the original interval from zero to 2,000 +into 100 cells then 2,000 divided by 100 + + align:start position:0% +into 100 cells then 2,000 divided by 100 + + + align:start position:0% +into 100 cells then 2,000 divided by 100 +each cell would be 20 milligrams long + + align:start position:0% +each cell would be 20 milligrams long + + + align:start position:0% +each cell would be 20 milligrams long +and this is exactly what our did it + + align:start position:0% +and this is exactly what our did it + + + align:start position:0% +and this is exactly what our did it +actually divided all the spectrum of + + align:start position:0% +actually divided all the spectrum of + + + align:start position:0% +actually divided all the spectrum of +values from 0 to 2000 into 100 cells and + + align:start position:0% +values from 0 to 2000 into 100 cells and + + + align:start position:0% +values from 0 to 2000 into 100 cells and +not only the spectrum from 0 to 100 but + + align:start position:0% +not only the spectrum from 0 to 100 but + + + align:start position:0% +not only the spectrum from 0 to 100 but +we still want to divide the interval 0 + + align:start position:0% +we still want to divide the interval 0 + + + align:start position:0% +we still want to divide the interval 0 +to 100 into 100 cells each of length one + + align:start position:0% +to 100 into 100 cells each of length one + + + align:start position:0% +to 100 into 100 cells each of length one +milligram and how can we do this well we + + align:start position:0% +milligram and how can we do this well we + + + align:start position:0% +milligram and how can we do this well we +simply need to think in terms of the + + align:start position:0% +simply need to think in terms of the + + + align:start position:0% +simply need to think in terms of the +original interval which was 0 to 2000 + + align:start position:0% +original interval which was 0 to 2000 + + + align:start position:0% +original interval which was 0 to 2000 +and if we were to break it into two + + align:start position:0% +and if we were to break it into two + + + align:start position:0% +and if we were to break it into two +thousand cells then each one will be of + + align:start position:0% +thousand cells then each one will be of + + + align:start position:0% +thousand cells then each one will be of +length 1 milligrams so now we know that + + align:start position:0% +length 1 milligrams so now we know that + + + align:start position:0% +length 1 milligrams so now we know that +actually we needed to set the brakes to + + align:start position:0% +actually we needed to set the brakes to + + + align:start position:0% +actually we needed to set the brakes to +2,000 so let's do this and now we obtain + + align:start position:0% +2,000 so let's do this and now we obtain + + + align:start position:0% +2,000 so let's do this and now we obtain +our refined histogram and we see new + + align:start position:0% +our refined histogram and we see new + + + align:start position:0% +our refined histogram and we see new +information here come up remember our + + align:start position:0% +information here come up remember our + + + align:start position:0% +information here come up remember our +initial conclusion was that more than + + align:start position:0% +initial conclusion was that more than + + + align:start position:0% +initial conclusion was that more than +6,000 foods have less than 200 + + align:start position:0% +6,000 foods have less than 200 + + + align:start position:0% +6,000 foods have less than 200 +milligrams of vitamin C but now that we + + align:start position:0% +milligrams of vitamin C but now that we + + + align:start position:0% +milligrams of vitamin C but now that we +refined our graph we obtained an + + align:start position:0% +refined our graph we obtained an + + + align:start position:0% +refined our graph we obtained an +additional level of information actually + + align:start position:0% +additional level of information actually + + + align:start position:0% +additional level of information actually +more than 5000 of them have less than 1 + + align:start position:0% +more than 5000 of them have less than 1 + + + align:start position:0% +more than 5000 of them have less than 1 +milligrams of vitamin C now a third way + + align:start position:0% +milligrams of vitamin C now a third way + + + align:start position:0% +milligrams of vitamin C now a third way +we can visualize the data is using box + + align:start position:0% +we can visualize the data is using box + + + align:start position:0% +we can visualize the data is using box +plots so let's go back to the console + + align:start position:0% +plots so let's go back to the console + + + align:start position:0% +plots so let's go back to the console +and create a box plot for sugar so the + + align:start position:0% +and create a box plot for sugar so the + + + align:start position:0% +and create a box plot for sugar so the +function we're going to be using is + + align:start position:0% +function we're going to be using is + + + align:start position:0% +function we're going to be using is +simply box plot and similarly to the + + align:start position:0% +simply box plot and similarly to the + + + align:start position:0% +simply box plot and similarly to the +histogram function the box plot function + + align:start position:0% +histogram function the box plot function + + + align:start position:0% +histogram function the box plot function +only takes as an input a single vector + + align:start position:0% +only takes as an input a single vector + + + align:start position:0% +only takes as an input a single vector +and in this case it would be the sugar + + align:start position:0% +and in this case it would be the sugar + + + align:start position:0% +and in this case it would be the sugar +vector and let's create a title that + + align:start position:0% +vector and let's create a title that + + + align:start position:0% +vector and let's create a title that +says box plot of sugar levels + + align:start position:0% +says box plot of sugar levels + + + align:start position:0% +says box plot of sugar levels +and is it the y-axis or the x-axis that + + align:start position:0% +and is it the y-axis or the x-axis that + + + align:start position:0% +and is it the y-axis or the x-axis that +we have to label it as you know the + + align:start position:0% +we have to label it as you know the + + + align:start position:0% +we have to label it as you know the +sugar level so if we're not so sure + + align:start position:0% +sugar level so if we're not so sure + + + align:start position:0% +sugar level so if we're not so sure +let's just plot it and oh this should be + + align:start position:0% +let's just plot it and oh this should be + + + align:start position:0% +let's just plot it and oh this should be +the y-axis so let's go back to the + + align:start position:0% +the y-axis so let's go back to the + + + align:start position:0% +the y-axis so let's go back to the +console and simply set the y label to be + + align:start position:0% +console and simply set the y label to be + + + align:start position:0% +console and simply set the y label to be +sugar in grams and now we have our box + + align:start position:0% +sugar in grams and now we have our box + + + align:start position:0% +sugar in grams and now we have our box +plot with the right labels what is it + + align:start position:0% +plot with the right labels what is it + + + align:start position:0% +plot with the right labels what is it +trying to tell us here it looks a little + + align:start position:0% +trying to tell us here it looks a little + + + align:start position:0% +trying to tell us here it looks a little +bit strange well the average of sugar + + align:start position:0% +bit strange well the average of sugar + + + align:start position:0% +bit strange well the average of sugar +across the data set seems to be pretty + + align:start position:0% +across the data set seems to be pretty + + + align:start position:0% +across the data set seems to be pretty +low it's somewhere around five grams but + + align:start position:0% +low it's somewhere around five grams but + + + align:start position:0% +low it's somewhere around five grams but +we have a lot of outliers with extremely + + align:start position:0% +we have a lot of outliers with extremely + + + align:start position:0% +we have a lot of outliers with extremely +high values of sugar there exist some + + align:start position:0% +high values of sugar there exist some + + + align:start position:0% +high values of sugar there exist some +foods that have almost 100 grams of + + align:start position:0% +foods that have almost 100 grams of + + + align:start position:0% +foods that have almost 100 grams of +sugar in 100 grams while candies are + + align:start position:0% +sugar in 100 grams while candies are + + + align:start position:0% +sugar in 100 grams while candies are +definitely among these foods so we just + + align:start position:0% +definitely among these foods so we just + + + align:start position:0% +definitely among these foods so we just +reviewed three ways in which we can + + align:start position:0% +reviewed three ways in which we can + + + align:start position:0% +reviewed three ways in which we can +visualize our data in week eight we will + + align:start position:0% +visualize our data in week eight we will + + + align:start position:0% +visualize our data in week eight we will +see more advanced visualization tools to + + align:start position:0% +see more advanced visualization tools to + + + align:start position:0% +see more advanced visualization tools to +make more informative plots in our next + + align:start position:0% +make more informative plots in our next + + + align:start position:0% +make more informative plots in our next +video we will see how we can construct + + align:start position:0% +video we will see how we can construct + + + align:start position:0% +video we will see how we can construct +and add new variables to our data set \ No newline at end of file diff --git a/QaY9AxkqifQ.txt b/QaY9AxkqifQ.txt new file mode 100644 index 0000000000000000000000000000000000000000..3b3ea6f1bce19c3c12eabfb13dff96ef6d42275b --- /dev/null +++ b/QaY9AxkqifQ.txt @@ -0,0 +1,5615 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high quality educational +resources for free. + +To make a donation or view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu. + +PROFESSOR: Today I want to +make some remarks about + +William Barton Rogers. + +You were supposed to read an +essay that I wrote about him, + +so I'm not going to go +into great detail. + +I don't want to repeat what I've +already written in the + +essay, but I thought I would hit +had some high points and + +then end up talking a bit about +this piece that Charles + +Eliot wrote called "The New +Education," because I readily + +admit that that is not the +easiest thing to read and + +surely not scintillating +prose-- + +you would not want to keep it up +with you at night and think + +you're going to read +it one AM. + +That wouldn't work. + +But it's an important essay. + +So we'll talk a bit about +that after I make + +my few remarks here. + +First thing I want to say is +that it's hard to believe that + +MIT has no full-scale +history-- + +history book, that is, a book +that's been written about the + +entire history of MIT. + +One does not exist. + +As close as we get to it is the +book you're reading now. + +And basically that consists +primarily of snapshots of + +critical moments in the +institute's history. + +I think it's a very good book, +but it's not a complete + +history of the Institute. + +And hopefully, someday, someone +will decide one is + +needed and actually write it. + +It will take it a lot of work +because the more I read and + +study about this place, the more +I realize that it has a + +very deep and very +diverse history. + +And it will not be an easy book +to write, in my opinion-- + +or at least to make it +a good book, that it + +really should be. + +But all the great universities +in the United States have + +these histories and MIT is one +of the few that doesn't. + +And I was sort of surprised +at that. + +I must admit, I didn't know a +thing about the history of MIT + +until about two or three years +ago, when I was asked to write + +this essay, and then, all of +the sudden, I, of course, + +started to read as much as I +could about it in preparing + +for the essay that I wrote. + +But I was really surprised that +there's no one big book + +you can go to and kind of +get the story there. + +My assignment by the editor of +the book Moments of Decision, + +his name is David Kaiser, and he +teaches in the STS program, + +history of physics. + +He's also a physicist. + +He has a Ph.D in physics. + +And he persuaded me to write +this essay, which I did + +because he was my colleague, +not because I wanted to, I + +must admit. + +But I'm glad I did in retrospect +because I learned a + +lot about this place +and especially + +about its early years. + +And so what that in mind, I want +to talk about, well, what + +did I learn from this extensive +reading that I did, + +and what did I learn especially +about William + +Barton Rogers the person and the +significance of his life? + +I think it's fair to say from +the outset that he is a very + +significant educator. + +In the larger history of +education, he has to be one of + +the more important people +of the 19th century. + +He came of age in the middle +of America's Industrial + +Revolution. + +He was born in 1804, so he was +in his 20s during the 1820s, + +right at the very moment when +the United States was really + +beginning to experience +factory systems, the + +mechanization of production, +the advent of railroads-- + +it was the moment. + +It was the right moment to be +in the country, to see these + +changes taking place. + +And he saw them, and he was +very, very interested in them, + +though he always considered +himself to be a scientist. + +He was initially educated by +his father, primarily, at + +William and Mary. + +His father was an academician. + +And he initially called himself +a natural philosopher, + +which would be a 19th +century word for + +a physicist, basically. + +Natural philosophy-- + +interesting name. + +But technology in those days, +interestingly, was also + +referred to as "the useful +arts." The word technology, in + +the 1820s, I don't even know +if it had appeared in the + +United States at that point. + +But in any case, it was a very +new word to the lexicon and it + +was rarely used until we had +the founding of this place, + +the Massachusetts Institute +of Technology. + +It's very interesting that +he chose that word. + +If I could go back and interview +Rogers, that would + +be one of the questions I'd want +to ask him, is why did + +you choose the word technology, +not Massachusetts + +Institute of Useful Arts, or +some more contemporary + +expression that was used, +frankly, more often than the + +word technology was, by 1860. + +In any cases here he is. + +He's a young man during +the 1820s. + +His first job out of college +was to teach in a small + +private school in Baltimore +Maryland. + +And it's in Baltimore that he +comes in contact with some of + +the really famous railroad +engineers of + +the early 19th century. + +All of these guys were West +Point-trained people. + +They were army engineers who had +been basically seconded to + +the Baltimore and Ohio +Railroad, a private + +corporation, to initiate surveys +and construction of + +this privately owned railroad. + +Talk about government in. + +It's a great example, in which, +here, the federal + +government is actually sending +its own personnel to a private + +corporation to get +the job started. + +And so he meets people like +William Gibbs McNeill and + +George Washington Whistler, +who, actually, + +are brothers in law. + +Whistler is the more interesting +of-- well, more + +historically interesting +of the two. + +They're both important engineers +because his son + +became a very famous artist, +James McNeill Abbott Whistler, + +is George Washington's son. + +And the famous portrait, +Whistler's mother, that sits + +in the Louvre in Paris is of +George Washington's wife, who + +was a McNeill as a young lady. + +So here you have these engineers +in Baltimore + +interacting with this young +teacher because he got + +interested in railroads and +wanted to give a lecture about + +the building of this new steam +powered railroad out of + +Baltimore westward toward +the Ohio River. + +And he started borrowing models +from these engineers to + +illustrate his lectures with. + +They were building very +interesting and fairly, not + +large scale models-- + +but I've seen some of them, +they currently exist in + +Russia, they're found in a +museum in St. Petersburg-- + +of the type of bridges that were +being built on the B&O + +railroad, and the types of +locomotives and rolling stock. + +A locomotive would be maybe that +long, a 440, that wide, + +it's this high, fairly +sizable model. + +But he was borrowing these +models to give lectures with + +and, in the process, began to +get interested in railroads, + +and especially because his +brothers, two of his brothers, + +actually worked for McNeill. + +Once they left the B&O, McNeill +came north to the + +Boston area to build a railroad +that, basically, is + +now part of the Northeast +corridor. + +It's the road between Boston +and Providence-- + +and did the surveys on that, +even those these two young + +were basically interested in +geology, McNeill hired them to + +help with the survey team, +and then, on the side, he + +encouraged them to do geological +explorations of the + +area, which they did. + +And they loved it. + +And they got to really admire +these army engineers, so much + +so that they really seriously +thought about becoming + +engineers themselves. + +That didn't happen, primarily +because they felt that army + +engineers had such an inroad +into the engineering business + +at that time, they were really +the only serious engineers in + +the United States, were these +West Point trained people, + +that they didn't think they had +much of a chance getting + +the good jobs compared to what +Whistler, and McNeill, and + +others were getting as a result +of their connection + +with the Army. + +Both Whistler and McNeill left +the Army in the 1830s and + +became private, consulting +engineers. + +And Whistler went on to engineer +not only the Western + +branch of what became the Boston +and Albany railroad, + +which was the first major +railroad to go over a serious + +mountain chain, the Berkshire +mountains. + +If you drive west on the Mass +Pike and go up over the + +Berkshires toward Albany, New +York, you're going exactly + +through the area that Whistler +ran a railroad through during + +the mid 1830s, late 1830s-- + +serious elevations there. + +And he did it. + +He got a lot of attention +for doing it. + +And one of the groups that paid +attention to him were + +these Russian engineers that +were sent to the United States + +by Tsar, I think +it's Nicholas. + +It's either Nicholas or +Alexander, but, in + +any case, he was-- + +DAVID KAISER: Weren't they all +Nicholas or Alexander? + +PROFESSOR: Nicholas and +Alexander, you've got to be + +one or the other. + +I can't be far wrong +on that one. + +But in any case, he was hired by +the tsar to go to Russia to + +engineer what is now called the +Moscow and St. Petersburg + +Railroad, which he did. + +He died in Russia, of +cholera, in 1849. + +But his body was brought back +to the United States and + +buried down in Stonington, +Connecticut. + +I have visited his grave. + +And I can attest that George +Washington Whistler now lies + +in Stonington, Connecticut. + +But he was a great engineer, and +he was an important here. + +He had a lot of influence on +Rogers and his brothers. + +And as a result of that, as I +said, they both contemplated + +engineering careers but then +backed away and decided, no, + +we are really educators. + +We're interested in this new +field called geology. + +Both William Barton and his +brother Henry Darwin Rogers + +became very, very eminent +geologists. + +In fact, Henry, his younger +brother, actually got an + +appointment at the University +of Glasgow as a chaired + +professor there during the-- + +I think it was during the +late 1840s, early 1850s. + +And it's in the process of +experiencing these things with + +these new railroads and +industrial ventures that + +really begins to turn his head +toward these "useful arts" and + +to think about how are they +related to the sorts of + +scientific interests +that he has. + +The other experience that he had +that's very important in + +all this was that when he was +teaching at the University of + +Virginia in the 1830s he was +appointed the head of the + +state Geological Survey, and +I've written about that in the + +essay, in which she had a +miserable time because of the + +political interest that were +vying with one another. + +He conducted the survey. + +He completed it, but the results +of the survey, which + +were important, were never +published because the + +legislature was bickering +among themselves-- + +sounds familiar-- + +about the costs, whether it was +a worthwhile project, the + +whole thing you might imagine. + +But in any case, Rogers was +disgusted with Virginia. + +Surely, by the late '40s, he was +really disgusted with the + +whole state legislature and +political process there. + +But in conducting these surveys +from one end of the + +state to the other, and in those +days, Virginia included + +the current state of West +Virginia, not just the current + +state of Virginia. + +It was a big state. + +He got interested, basically, +in things like mountain + +formations and very much +interested in where mineral + +deposits were located and +things like that. + +But the big problem was finding +assistants that could + +help him conduct the sort of +geological work that he needed + +to do in order to finish up the +survey and make a report. + +And that was another stimulus +toward his interest in trying + +to do something with combining +science with the useful arts. + +So those are, I would say, two +critical moments during the + +1830s in which he really began +to begin to think about + +establishing some sort of what +we would call a Polytechnic + +Institute, or Institute +of Technology. + +He and his brother both started +talking about this as + +early as 1829 in Baltimore. + +But then it got continued +throughout the 1830s and well + +into the 1840s. + +And that's really how the whole +idea of what this place + +is about got started. + +Rogers also saw, through these +years, that there was a crying + +need for people to do +engineering work and meet what + +he referred to as the "wants +of the age." This was the + +great field, the open field-- + +lots of jobs and possibilities +for advancement. + +And he saw that, and, +again, it stimulated + +his interest in education. + +So as a result of this, he +develops a plan for a + +Polytechnic Institute, the first +draft of which, I think, + +was written as early as 1829. + +And then over the next 30 years +he and his brother sort + +of elaborate on this plan +about how would + +they organize it? + +What disciplines would +be included? + +But the key, I think, the key +idea that they developed over + +these years was trying to +combine, trying to develop an + +educational system that would +combine science with the + +useful arts, make them relevant +to one another and + +especially inform the useful +arts about what science could + +reveal to them-- the +understandings of chemistry, + +or physics, or whatever. + +And of courses, as you've read, +the finality of this + +comes in 1861, when he receives +a charter from the + +state of Massachusetts to +establish what is called the + +Massachusetts Institute +of Technology. + +Now in that, he'd had to +do a lot of lobbying. + +He had learned how to work with +politicians through that + +miserable Virginia experience. + +I think it made him +a wiser man-- + +maybe a cagier person in terms +of learning how to work with + +politicians or to get +around the obstacles + +they put in this way. + +It's during the early questions +about the charter + +for MIT, for example, that the +governor of Massachusetts, who + +was a Harvard graduate, first +proposed the idea of, why + +create this MIT as a +separate institute? + +Why not combine it +with Harvard? + +It's one of those early +questions about, well, why not + +combine it with Harvard rather +than make it a separate + +institution? + +Rogers resisted that throughout +this entire life. + +And there were several other +attempts made during his + +lifetime to try to merge +MIT with Harvard. + +But it began very early. + +And it began first with the +government of Massachusetts, + +who would like to have +seen that sort of + +combination put together. + +But once they got the charter, +the big challenge then was to + +try to get the place going. + +And the problem was that he got +his charter in April 1861, + +and what happens in +1861, in April? + +Civil War. + +And so a war breaks out. + +It makes it difficult for him +to raise money, basically-- + +very difficult to raise money. + +And some scholars who have +studied the history of MIT + +think that maybe it was a good +thing that there was a war, in + +terms of his interest, because +it gave him time to complete + +this plans and to work the +political process in a way + +that allowed him to +eventually get the + +Institute started in 1865. + +There may be some truth to that, +but I think the real + +problem that he faced +1861 was money. + +And that was a problem MIT was +going to face for the next + +four years or so. + +MIT was always running in the +red, basically, well into the + +late 1890s and probably +beyond that. + +I just haven't studied that +much beyond the fiscal + +situation beyond the 1890s. + +But in any case, he +got his charter. + +He has to hire faculty. + +He has to choose and acquire a +site to initiate classes in. + +He has to raise this money. + +There are a lot of things that +have to be accomplished. + +And I think one of the big +godsends of the period was + +that there was a law +passed in 1862. + +It was a federal law, part of +the Lincoln administration's + +political agenda called the +Morrill Land Grant Act. + +And I remember reading about +this when I was your age and + +being totally bored by it. + +But it turns out that that is +a very important piece of + +legislation because it led to +the establishment of what we + +call the land grant university +system in this country. + +All the big state universities, +basically, are + +related to that land +grant act. + +Some very directly, and others +less so, but, nonetheless, + +most of them-- + +Texas A&M, Penn State, Ohio +State, Michigan State, + +Wisconsin, Berkeley, you know, +you can go across the country + +and almost choose. + +In every state, there's at least +one institution that was + +founded under the Morrill Act. + +Well, that Morrill Act +was passed in 1862. + +And basically, what it said +was that for each + +congressional representative +that you had in the US + +Congress, the state would get +30,000 acres of land, which it + +in turn could convert into +script and sell the script, or + +the rights to the land, as +a way of raising money to + +establish agricultural +mechanical colleges within the + +state boundaries-- + +A&Ms, if you want to +call them that. + +So Massachusetts, I think, +had 10 congressional + +representatives and +two US Senators. + +So it got a fairly sizable chunk +of land in the Midwest. + +If I'm not mistaken, it was out +in the area of northern + +Iowa, southern Minnesota, in +that area, where a lot of this + +land was located. + +People in Minnesota and Iowa, +by the way, were not happy + +that the federal government was +giving away land in their + +states to states that had +nothing to do with them. + +You can imagine how people in +Minnesota must've felt about + +this huge chunk of land going +to New York State, or + +Massachusetts, or wherever. + +But in any case, that converted +into substantial + +funds that were used to found +not only MIT but also the + +University of Massachusetts +at Amherst. + +And basically, MIT got a +third of those monies + +over a 30 year period. + +It was given to them +in increments. + +They got a sizable amount of +money, well over $300,000. + +That may not sound like much +today, but if you convert it + +into 2008 dollars, it's +a big hunk of money. + +I don't know but I've-- + +DAVID KAISER: Well, it would +put you through MIT today. + +PROFESSOR: It would put +you through MIT today. + +That's a good way to put it. + +Yeah, so it's a sizable +amount of money. + +DAVID KAISER: Plus a +couple vacations. + +PROFESSOR: But probably just as +important as the grant from + +the state itself, which +consisted not only of money, + +but also of land, over +in the Back Bay-- + +MIT was first established not +here, where we are today, but + +over in the Back Bay +near Copley Square. + +If you're familiar with that +area, the original building + +was very close, block or two, +from Copley Square. + +And it stayed there until +1916, pretty much. + +But in any case, the money for +all that came from the state + +of Massachusetts. + +So the state was important +in all this. + +Without the state, I would, in +fact, question whether private + +donors would have stepped +forward to donate money to MIT + +because they weren't sure +about its future. + +But when the state began to +invest in MIT, that sort of + +gave a signal that, yeah, +MIT's got a future. + +I'm going to pony up some money +and give --and one of + +the big donations that came very +soon after MIT got the + +state funds was a donation that +I begin my essay with, + +this doctor-- + +what's his name-- + +DAVID KAISER: Walker? + +PROFESSOR: What is it? + +DAVID KAISER: Walker. + +PROFESSOR: Walker, yes. + +William Walker, a physician who +had invested in industry + +in this state. + +This was a leading +industrial state. + +And he ponied up $60,000-- + +a lot of money for a private +individual in those days. + +DAVID KAISER: On the last +day before the-- + +PROFESSOR: In the last day, +yeah, so it was an iffy + +proposition from +the beginning. + +And Rogers, I think one of his +great skills was as a, in a + +way, small p politician, +a lobbyist. + +He was very effective at +lobbying people, and raising + +funds, and keeping this +institution going from one + +year, literally, one +year to another. + +Because every year, as I said, +it was running on the red. + +But he made it go. + +DAVID KAISER: Something about +Back Bay, too-- because maybe + +not everybody knows that +what is now Back + +Bay was once a Bay. + +PROFESSOR: Absolutely. + +DAVID KAISER: And I hadn't +really remembered until I was + +reading the reading last night +that part of the initial + +interest was-- + +they filled in the Back Bay to +make what is now Back Bay, + +which was a huge engineering +project in and of itself. + +And then there was interest +in using that land for + +educational purposes, which +Rogers then sort of satisfied + +to some degree. + +PROFESSOR: Right. + +And I think I mentioned in the +essay that the initial + +proposal was not just for an +industrial school, MIT, but + +was also for a natural history +museum and a society of arts. + +It was a 3 part combination that +was initially proposed. + +And eventually, of course, +MIT was the + +one that really lasted. + +And the other two sort of +slipped by the wayside. + +But in any case, that's the +story of the beginning + +because, I think, in the early +days, if I'm not mistaken, + +that one of the early courses +at MIT was in mining and, + +what's the other-- + +DAVID KAISER: Metallurgy. + +PROFESSOR: Mining +and metallurgy. + +And in those days, geology +would've been + +lumped into that area. + +And then later, it becomes-- + +yeah, yeah. + +Now, I can't absolutely +swear that's the + +case, but that's my-- + +what would say say, an +educated guess, I + +guess, would be. + +So to look at Rogers and just +say, OK, what are some of the + +important points to remember +about him? + +One is, he's a good lobbyist. + +He keeps the place going. + +He keeps the vision alive, OK? + +And secondly, there's +the vision itself. + +You see it on the great +seal of MIT. + +You know, interestingly, if +you look at the seal, it's + +interesting. + +It says mens et manus-- + +mind and hand. + +Science and the useful arts, +another way to think of it. + +But clearly, that vision of the +combination of science and + +the useful arts was there +from day one. + +And that seal was actually +approved in 1864, if I'm not + +mistaken Rogers was on the +committee that, you know, + +approved that seal. + +And he obviously played a role, +I mean, I think his + +vision is sort of stamped, +literally, into the seal + +itself, of what this place +was going to be. + +One curious thing about that +seal, however, I'll + +point it out now. + +It's not original with me, but +a colleague of mine, years + +ago, pointed it out to me, +and I have thought + +about it ever since-- + +was that when you look at this +seal, you have a craftsman, or + +an industrial worker, and a +scholar, OK, the scientist and + +the useful arts standing next +to a pedestal, and then the + +words mens et manus below, +and the date of + +the founding of MIT. + +The interesting thing though is +that, in Rogers' vision he + +wanted to combine, he wanted +each of them, science and + +useful arts, to inform +one another. + +That was the special thing, +the idea that he had. + +This was a new way of +educating people. + +And yet these figures, science +and engineering, or science + +and useful arts, they have their +backs turned to each + +other, as if they're not +conversing at all. + +Curious. + +I don't know it if was for +aesthetic purposes or what, + +but from a didactic point of +view, they should have been + +facing each other, and having +discussions, and interacting. + +Clearly, they're not +doing anything. + +They're sort of both in +their own worlds. + +And that's an interesting +comment, I think, just on the + +seal, not necessarily about +Rogers' vision. + +But he has this important idea +about the combination of the + +two, which is very important. + +And in the essay, I put a lot of +emphasis on the importance + +of laboratory education there, +in which students are not just + +being given lectures and +demonstrations by the + +professor using the apparatus, +but, in fact, they're allowed + +to go in and perform experiments +themselves using + +the apparatus. + +One of the reasons why MIT was +constantly in financial + +difficulty was the need to +maintain the laboratories that + +were so critical to the +education of its students. + +Laboratories are very expensive, +to this day + +probably the most expensive +item in the MIT budget, I + +would think-- one of the +most expensive ones. + +Look around us at these new +buildings that are going up + +just in the biological sciences +and think of the + +expense that has been +invested in them. + +And it was no less true +in the 19th century. + +And it had a special meaning for +Rogers because he wanted + +students to be immersed in that +experimental process and + +not just lookers-on. + +He wanted them involved +in the process. + +And I think that's one of the +really distinctive things + +about MIT, then and today. + +I keep thinking that vision of +1861, 1864, of Rogers can be + +seen in the UROP projects. + +And several of you have written +in your reflections + +about this today-- + +different programs that exist at +MIT that have that sort of + +active involvement of students +that, in the days of the + +1860s, just didn't exist at +other places, or surely not to + +any extent like it did at MIT. + +The other thing that Rogers +had was an eye for talent. + +Every great leader needs to +surround themselves with + +capable people. + +And the more capable, +the better. + +And Rogers, I don't know if +you want to call it good + +fortune or just the ability to +spot people and hire them. + +But he hired a very +talented staff. + +I think there were something +like 20 professors, maybe not + +even 20, by 1870, five years +after classes started. + +But at least half of them were +very, very competent people. + +And two of the most important +were a guy named Francis + +Storer, S-T-O-R-E-R, and +somewhat younger guy, but not + +a lot younger, Charles Eliot, +both of whom were chemists, + +both of whom were Harvard +educated, and, it turns out, + +both of whom were +brothers in law. + +Storer married Eliot's sister. + +And Storer came to MIT first. + +He was one of the first faculty +hired at MIT, to set + +up a chemistry department +here. + +And then Eliot, who was studying +in Germany, was hired + +like in 1867 to come in and +fill out that enterprise. + +And they end up building +one of the first really + +experimental research oriented +laboratories in the United + +States, academic, anyway. + +And they also are the first to +write textbooks for the study + +of chemistry, and chemical +experiments, and things like-- + +two very famous textbooks that +were published during the + +early, well, the late 1860s +and early 1870s. + +So they're important people. + +Now the interesting thing is +that Eliot was at MIT a very + +short period of time. + +He came and '67 and he +left in '69 to become + +President of Harvard. + +And interestingly, it's Eliot +who really initiates all these + +attempts to merge Harvard +with MIT. + +The essay that you read today +called, "The New Education," + +same guy, Charles Eliot, the +author is Charles Eliot. + +He wrote that while he was at +MIT, but the same year that + +essay was published, he becomes +president of Harvard. + +And immediately, he starts +making overtures to William + +Rogers about, come +on, Bill, let's-- + +I don't know if they'd +call him Bill. + +I've often wondered, what did +they call William-- did + +William Rogers have +a nickname? + +We had a reunion over in +Burton-Conner about two or + +three weeks ago, and they +had this big cut + +out picture of Rogers. + +And one of the students from +Burton-Conner came over and + +clipped a little ID badge on +him saying, "Billy." But I + +can't imagine, William Rogers, +does not strike me that you + +would walk up and call +him Billy Rogers. + +I don't know if he had +a nickname or not. + +But in any case, Eliot liked-- + +DAVID KAISER: Mr. Rogers. + +PROFESSOR: Pardon? + +Mr. Rogers, that would +even be better. + +Yeah, Mr. Rogers. + +DAVID KAISER: And they called +MIT Mr. Rogers' neighborhood. + +PROFESSOR: Well, you're +just full of neat + +observations today. + +DAVID KAISER: That's +my job, [INAUDIBLE] + +PROFESSOR: That's good. + +That's good. + +You remind me of Waldorf over +and-- you know, the muppets up + +in the balcony? + +DAVID KAISER: [LAUGHS] + +PROFESSOR: You're +Waldorf today. + +Anyway, Eliot really liked +what he saw at MIT. + +He clearly thinks that MIT +is the core of this "new + +education." This is where +the action was at. + +And he tried very hard during +his presidential years at + +Harvard-- and he was president +of Harvard for at, what, 35 + +years or so? + +A long time. + +Never happened. + +But that was one of his +fondest wishes. + +And he was one of these early +hires that William Barton + +Rogers made here. + +Clearly, he had sold Eliot +on the MIT vision. + +There were others. + +Edward Pickering, like Eliot and +Storer, established a very + +famous lab in physics here. + +And he was literally Rogers +successor as the teacher of + +physics at MIT-- + +again, another Harvard +graduate. + +All these early professors are +pretty much Harvard graduates + +who came to MIT and then, like +Storer and Eliot, often left + +MIT to go back to Harvard, +interestingly. + +I don't know exactly why. + +Eliot was a very persuasive +person, but I'm sure Harvard + +could shake a lot more money in +their faces, too, in terms + +of salaries and things +like that. + +That's probably important, +an important attraction. + +So Pickering, as I recollect, +also returned to Harvard at + +one point in this career. + +But he was a very important +laboratory builder here at MIT + +that established, again, the MIT +model for spreading this + +new vision of education +around the country. + +And then finally, in +architecture, another Harvard + +graduate, William Ware, +establishes the Department of + +Architecture at MIT. + +It's the first in the country, +and very successful, very much + +oriented towards this hands on, +laboratory oriented design + +process in architecture. + +He was at MIT for +about 15 years. + +And then he leaves to go to +Columbia and establish a + +similar school at Columbia. + +He's considered the leading +educator in architecture of + +the late 19th century. + +So you have here, in this +early faculty, some very + +interesting and significant +people. + +And I think the important thing, +for the purposes of our + +discussion today, is that +Rogers hired these guys. + +He had an eye for talent. + +And there's nothing like having +great talent around you + +to build a great institution. + +And that was underway +by the 1870s. + +People were actually writing to +Rogers by the 1870s, like, + +within five years of the +founding of this place, + +saying, MIT is making +itself heard. + +And that reputation continues +to gain momentum throughout + +the decades of the late +19th century. + +So much so that in the paper +that I wrote, I refer to + +Francis Amasa Walker, who was +the third president of MIT + +making his annual report in +1894, in which he comes out + +and says, basically, thanks +to the founders of this + +Institute, and especially to +William Rogers, the battle of + +"the new education" " has won. + +Well, the new education meant +that MIT had now become the + +great model of this new way of +educating people toward a more + +integrated curriculum built +around science and + +engineering. + +That was a new model. + +And when you look around the +country today, virtually every + +major university has sort of +bought in to that model. + +Even a number of small colleges +have, but especially + +large state universities-- + +very much influenced by +this MIT approach. + +Now the final point to be made +about Rogers, I think, is that + +he's one of the country's +first geologists, + +professional geologist. + +He's one of the founders +of the field + +in the United States. + +He is also a founder of the +American Association for the + +Advancement of Science. + +He's not and he's not on the +inside of that operation, but + +he's definitely consulted about +it, is an early member, + +and plays a role in it. + +But he is an important geologist +in the history of + +science in this country. + +And he's also an early defender +of Charles Darwin. + +Darwin's Origins of Species, +the famous book on + +evolutionary theory, was +published in 1859. + +And Rogers was one of the first +in the Boston area to + +embrace that theory, +and defend it, and + +argue that it had-- + +from his geological perspective + +was a viable theory. + +He was opposed, very vigorously, +by a zoologist + +from Harvard named Louis +Agassiz, who, in more than one + +time, tried to do in Rogers, +both as a geologist and as the + +founder of MIT. + +But, again Rogers had staying +power and was able to make its + +way through all these crises. + +But I think as a geologist, he +often gets forgotten in that + +area, even though he +was an important + +contributor to that field. + +Now what are the take +home points of the + +essay that I wrote. + +I'll give you three. + +One is obvious. + +It's the sustainability of +Rogers' vision for MIT-- + +the mens et manus theme. + +The idea of combining, bringing +together science and + +the useful arts. + +It's a remarkable continuity, +if you ask me. + +I think it's something that has +maintained itself right up + +to the present. + +That's amazing. + +This place is 150 years old, and +yet the founding vision of + +the place still informs +it in many ways. + +Now that doesn't mean there +haven't been changes. + +There surely have been. + +And we'll see them +during the term. + +But that basic concept has +maintained itself. + +That's amazing to me. + +Another thing that's important +to note here is the role of + +the state in the founding of +MIT, the fact that the state + +of Massachusetts, funded by +the federal government, + +basically, put up a lot of the +real seed bed money that was + +used to get this +place started. + +And then that, in turn, +attracted private + +donations to MIT. + +But as late as the 1890s, MIT +was petitioning the state of + +Massachusetts for increments of +$25,000 a year, simply to + +try to support the building of +labs and stuff like that. + +So Massachusetts have a long +history of involvement with + +MIT, even though this was +supposedly a "private + +corporation." It's curious. + +It's a land grant school that +is a private corporation. + +Not many were like that. + +Most were state universities +that were state controlled and + +did not have this word +corporation. + +You might have been a member of +the board of trustees, but + +you were not a member +of the corporation + +like we have today. + +So again the state is +important here. + +And then finally, just about +MIT's significance, it's the + +new education that's +important. + +It's a new breed of cat that's +being developed here, and it's + +one that had legs. + +It's probably had, I suppose, +this sounds so much like a + +homer lecture, but +it is, in a way. + +I'm enthusiastic about +the history of MIT. + +Maybe it's because I haven't +learned enough about it yet. + +But the vision for MIT +had an impact. + +It made impacts elsewhere. + +It continues to have that. + +We'll talk about, later in the +term, about how the MIT model + +is now being exported to +Singapore, and to India, and + +all over the world. + +So it's had enormous, +enormous impact. + +And that's not something +to be sneezed at. + +And it's really why Charles +Eliot wrote that essay called + +"The New Education," was to +point out, this is something + +new and different. + +This is worth attending to. + +And he does a survey of all +these various schools and says + +the real place where the +action is is MIT. + +That's 1869. + +Within months, he was going to +become president of Harvard + +and, as I said, made numerous +attempts to try to bring MIT + +into the Harvard fold, +unsuccessfully. + +So David suggested that's +my remarks, OK. + +Brilliant. + +Aren't they? + +Eli, you thought they were +pretty good, huh? + +That's good. + +I know all these people. + +So you're wondering, why is he +talking to them, you know? + +Anyway, David suggested, before +the class started, that + +we take a closer look at +Eliot's piece "The New + +Education." I debated about +whether we should have you + +read this or not because, +frankly, it's pretty boring. + +It's not an easy +piece to read. + +It's written in a very stilted, +19th century style. + +And yet it's says things, if you +can make your way through + +it, it does say things, +I think, that are + +important to note. + +And so, this is basically +Charles Eliot's take on the + +state of education, higher +education, in the United + +States circa 1869. + +That's really what this +essay is about. + +And the big distinction he makes +is that he talks about + +how there are basically three +different types of higher + +education institutions +in the United States. + +There are the classical colleges +that teach Latin and + +Greek, mathematics, the typical +curriculum aimed at + +cultivating an educated +gentleman for society. + +That's where gentlemanly +people went. + +Ladies, I'm sorry, were not +admitted to those schools in + +those days. + +Most women, in those days, if +they went to college at all, + +and many of them did +not, went to-- + +my grandmother, who went to one +of these college called + +state teachers institutes, or +educational institutes. + +But rarely would you see women +on the campus of Yale. + +I don't even know +if Yale admitted + +women, did they in the--? + +DAVID KAISER: 1969. + +PROFESSOR: Wow. + +See? + +It's a good-- + +OK. + +Well, Harvard had Radcliffe. + +So they're next door neighbors, +but there's this + +divorce that exists. + +Now, interestingly, Rogers, +from day one, said we will + +admit women to this place. + +A very, very small +number came. + +And most of those who did come +were called special students. + +They were not regular students +like you are but rather + +special students who were part +time, basically, part time + +students, women who were working +in the area who wanted + +to take a chemistry class or +something, could enroll here. + +But for it's day, that was quite +a revolutionary and open + +minded thing to do, I think. + +But he was very open to that. + +He was very much a reformer, +I think. + +He was involved in the +abolitionist movement. + +And David pointed out today that +one of his friends from + +Virginia, a guy named Edmund +Ruffin, was actually one of + +the first to fire the +Confederate cannons on Fort + +Sumter in 1861. + +So here's this man coming out +of Virginia who was imbued + +with this slave oriented ethos +that's pervaded Virginia prior + +to the Civil War, who was open +minded enough to see the + +problems and downright evils of +slavery, resist them, and, + +eventually, remove himself +from the South + +and come to New England. + +That's one of the reasons +he moved here. + +He was just so sick of the +violent society that Virginia + +had become by the 1850s, +especially around slavery. + +A lot of his problems came +from that direction. + +Well, when Eliot writes about +"The New Education," he + +doesn't use that phrase +a lot in here. + +You really have to +kind of look-- + +he may have mentioned the term +new education or some variant + +of it maybe three or four times +in the entire essay. + +It's not something he's +pounding away at. + +But he's making as interesting +comparisons, first, between + +these three kinds of +institutions that are trying + +to organize educational +framework around the useful + +arts and science. + +And he argues that two of them +are just abject failures, + +basically, there are schools +like the Lawrence School at + +Harvard, or the Sheffield +School at Yale, or the + +Chandler School at Dartmouth, +that make the attempt but can + +never quite achieve what is +needed to be done because + +their faculty come from +the school itself. + +And as a result, the faculty +loyalties and the degree of + +involvement in these new +ways of educating + +students is never complete. + +It's always sort of +a halfway process. + +And that's something that +bothered Eliot a great deal, + +especially about Harvard because +the Lawrence School + +was heavily endowed +for its day. + +And yet it had really had a +sort of a meager record of + +turning out students who +were well educated + +in the useful arts. + +And so that's a problem. + +There are other types of +colleges that he talks about + +with reference to the useful +arts, smaller schools like + +Union College up in Schenectady, +New York or Brown + +University down in Providence. + +And basically, the argument is +somewhat similar there, is + +that it's hard to introduce this +new concept of combining + +useful arts and science in +environments that have been + +completely oriented toward +the classical education + +up until that time. + +It's very difficult +to do that. + +And as a result, he says, it's +really to the third type of + +school, the RPIs, the MITs, are +the two main ones where + +this model is more likely +to succeed. + +And there, he says that RPI's +been quite successful at it. + +It's really the first civilian +engineering school founded in + +the United States. + +It dates to 1824. + +And RPI is basically a place +that trains civil engineers. + +It does not get into mechanical +engineering or + +metallurgical engineering, +things like that. + +It's strictly oriented toward +civil engineering-- by the + +time the Civil War, +very successful. + +But it's really to MIT +that he looks. + +And he says now here is the +model because it's so open to + +educating not only civil +engineers but mechanical + +engineers, architects, +metallurgical engineers-- + +MIT has a menu by the late 1860s +that no other school + +really has. + +And so that is, I think, +a distinctive + +comment that he makes. + +But basically, I read this, +and for me the takeaway is + +that Eliot loves MIT. + +He sees MIT as the new direction +for higher education + +and that's doing something +different than any other place + +has ever done. + +It's a good question. + +The interesting thing, I wanted +to note, here, though + +is that on page 216 near the +end, yeah, he's talking about + +RPI and MIT, but he makes no +reference to the US Military + +Academy, which is arguably the +first engineering school in + +the United States. + +It's modeled after the French +Ecole Polytechnique-- + +except for a footnote at +the bottom of 216. + +Did you see this note? + +He says the United States Naval +and military academies + +are not referred to at length +because-- they're not refer to + +at all, basically, because +access to them is not free. + +A thoroughly vicious system +blah, blah, blah. + +He does not like the +military academies. + +But he completely erases +them from the essay. + +Did you have your hand up? + +AUDIENCE: Um, not really. + +PROFESSOR: Huh? + +AUDIENCE: No. + +PROFESSOR: Oh OK, I thought +you were waving your hand + +going, I object! + +He's just anti-militarist, +or something. + +But those are important +places-- + +especially West Point. + +In fact, I think I say it in my +essay, that the president + +of Brown University, Francis +Wayland, made a comment in the + +1850s that West Point had +trained more engineers then + +all the other colleges in the +United States put together. + +Well, that says something. + +It's not a big school. + +And it also tells you about the +need for more engineers in + +the country because West +Point could not produce + +all of these people. + +Hence the reason why MIT became +so important by the + +later decades of the +19th century. + +And where did early MIT +graduates go to work? + +Many of them went +to railroads. + +That was the big industry +after the Civil War. + +And many of them go into the +railroad industry as managers, + +engineers, railroad builders. + +Many go into chemical industries +that are beginning + +to emerge during this +period too. + +It's interesting, for example, +that the du Pont family sends + +the best and brightest of their +family, of young people, + +up here to get educated. + +Pierre du Pont, one of +the really important + +industrialists of the early 20th +century, is a graduate of + +MIT class of 1890. + +And there were other du Ponts +that came here, too, but he's + +probably the most important. + +And Arthur D. Little, famous +AD Little Laboratories. + +I don't know if they're still, +are they still in operation? + +Private research laboratories +in chemistry? + +DAVID KAISER: I belive AD Little +is still in operation + +but they sold off +the R&D lab-- + +PROFESSOR: They did, OK. + +DAVID KAISER: To an MIT +alum, actually, Kenan + +Sahin, owns it now. + +And it's got a different name. + +PROFESSOR: Oh, he did? + +OK. + +Well, there's a list of very +eminent engineers, chemists, + +applied scientists that are +coming out of MIT by the 1890s + +that go on to really play a +big role in the commercial + +development and +industrialization of the + +United States in the +20th century. + +So MIT has had an impact. + +I don't know if you want to +say any more about Charles + +Eliot's piece here. + +DAVID KAISER: I would +read through little + +bit of it in detail. + +PROFESSOR: Go ahead. + +DAVID KAISER: How many people +brought the piece + +[INTERPOSING VOICES] + +PROFESSOR: Can you get it +off the scholar site? + +DAVID KAISER: If you have it, +maybe pull it out because it's + +sort of worth, I think, reading +parts of it in some + +detail because, first of all, +it's a good exercise in what + +we call close reading, +were how you-- + +I mean, the language +a little foreign. + +It's not very foreign, but +what's being said between the + +lines, or what's he assuming +that people are saying. + +And I think some of it is +relevant to both what + +[? Rowe ?] was saying, and +even to MIT today. + +I'm sorry? + +It is on Stellar, yeah, so +if you have a laptop + +you can find it. + +You know, he starts out +with this line-- + +"what can I do with my boy?" +Which is very interesting. + +I mean, obviously it's only +boys and men that he's + +addressed like [? Rowe ?] +mentioned, that was the + +language of the day, up until +a couple of decades ago. + +But, sort of addressed to the +parents, and of if you read + +down a little bit, this is what +a parent might say, I + +want to give my boy practical +education. + +One that will prepare him better +than I was prepared to + +follow my business, or any +other active calling. + +And I like that phrase active +calling, because implied there + +is there are passive callings. + +I wonder what he means by +a non active calling. + +I would guess he would mean the +clergy, or probably law, + +and he comes back to +them a little bit. + +And then he says this is a +problem that everyone has, but + +the difficulty presses more +heavily-- still in the first + +paragraph-- + +on the thoughtful American +than on the European. + +And so he's making a distinction +that the + +conditions of this country are +special, in some way, for this + +kind of education. + +It's not the modern phrase of +old Europe, there are special + +things here, because the +American is free to choose, in + +a way, a way of life for himself +and his children. + +And then-- + +a couple lines down-- in the +face of prodigious material + +resources of a vast and new +territory, he is more fully + +awake then the European can be +to the gravity and urgency of + +the problem. + +Also a really interesting way to +start out at the beginning, + +that there are special things +about this country. + +That's not a new idea, American +exceptionalism, is + +what historians call it. + +But, the conditions here are +different than in Europe. + +Partly because of the huge +size of the place. + +Partly because of the huge +amount of resources. + +And that makes the American +more fully awake. + +And yet, he has fewer options +than any other, except + +possibly the English, of +solving the problem. + +And then on the next column, +he refers to implicitly + +particularly the French +engineering schools. + +For more than a generation the +government schools of arts and + +trades, arts and manufactures, +bridges and highways-- + +one of the famous French +engineering school is Ponts Et + +Chaussees, the school of +bridges and highways-- + +Ecole Des Mines-- + +another famous French +engineering school-- + +mines, agriculture, and commerce +have introduced + +hundreds of well trained +young men. + +They begin as subalterns, +basically low people on the + +totem pole, but soon become the +commission's officers of + +the army, and of industry. + +Which is interesting too, what +is the problem that the + +European engineering schools +are feeding? + +They don't have vast territory +remaining, they don't have + +vast resources in their +countries, where are all those + +engineers going, if in the US +they're going out west? + +Into the colonies. + +It's a problem of maintaining +the empire. + +He doesn't talk too much about, +he does use the word + +empire in there, but in a way +he's sort of arguing that + +America has its own empire +right here, and French + +particularly, German, English, +they're all building railroads + +in the colonies, a little +bit more in + +the later 19th century. + +PROFESSOR: Think, for example, +the British and India, huge, + +huge, and that's only a +part of the British + +empire in that period. + +It's a huge empire. + +DAVID KAISER: Then he this +great line, The American + +people are fighting +the wilderness, + +physical and moral. + +Which is funny, it's also +interesting, this is four + +years after the Civil War. + +In fact, most of the stuff we've +been reading, relatively + +recent, doesn't mention +the war in here. + +You have a country that just +lost the better part of a + +million people. + +The South has been destroyed to +a large degree by the war. + +The young people's population +has been destroyed. + +I don't know, what was the +population of the US in the + +time of the Civil War? + +PROFESSOR: I want to say it's +around six million maybe? + +DAVID KAISER: So six million, +even if you lost six-- + +PROFESSOR: I'm not sure. + +DAVID KAISER: --hundred thousand +people out of that. + +10% of the population. + +Extend that out today, that's +like you having a civil war + +where you are losing tens +of millions of people. + +Nobody would have been +unaffected, and he doesn't + +mention it in this piece, +which is also very + +interesting. + +PROFESSOR: I know one thing, +the South lost 25% of it's + +younger men during that war. + +25%-- + +DAVID KAISER: That's huge. + +PROFESSOR: --that's a big, +big, [INAUDIBLE] + +DAVID KAISER: The American +people are fighting the + +wilderness, physical +and moral. + +So, you wonder what that, +physical wilderness is + +obvious, moral probably is +referring to the, I would + +imagine, the Western +wars and-- + +PROFESSOR: Yeah. + +DAVID KAISER: --fighting the-- + +PROFESSOR: Indians. + +DAVID KAISER: --Native +Americans there. + +And that's his vision +of the battle. + +At the same time, trying to work +out the awful problem of + +self government. + +So he's tying these basic ideas +about education to both + +the physical state of the +country, and also the + +ideological and government +state of the country. + +PROFESSOR: One thing to note +in all that is that William + +Tecumseh Sherman was a very +famous Civil War general, he's + +the one that burned Atlanta, +and did the famous march to + +the sea, was asked during the +1870's, what he thought about + +the quote "Indian problem" +Here's this movement west, and + +the part of white settlers. + +He says, nothing to worry +about, we're building + +railroads in the West and that's +driving a stake into + +the heart of the American +Indian, or + +something like that. + +That was going to do them in, +is the engineering of these + +new railroad technologies, is +just going to overwhelm them, + +and it did basically. + +DAVID KAISER: So down in the +bottom of that column he talks + +about all these frustrations, +but he knows the greatness of + +the material prizes to be won. + +So it's not an appeal for moral +elevation necessarily, + +or this and that. + +It's an appeal for material +prizes, which is very much on + +the mind of Americans, +since the founding + +On the next page, just +interesting phrases on the top + +left, on 204, These old ways +have trained some boys well, + +for the life of 50 or 100 years +ago, And the American + +will not believe that they are +applicable to his son. + +For the reason that the kind of +man which he wants a son to + +make, did not exist in all +the world 50 years ago. + +This was 1869, and somebody +mentioned in one of their + +response papers that they +appreciated, from the reading, + +how close the revolution still +was, in that most of the + +fathers of these people would +have been directly involved in + +it, which is correct. + +So, 50 or 100 years ago +there's been all this + +political upheaval and America +was a very agrarian society, + +but everywhere was, and he's +really referring to what we + +now call the Industrial +Revolution there. + +Entirely new kind of people +are required. + +Then also down in that column, +I think this is very + +interesting too, it requires +courage to quit the beaten + +paths in which the great +majority of well educated men + +have walked, and still walk. + +So he's basically saying, and +you even still hear this to + +some degree today, the MIT +graduates especially if + +they're successful, will enter +a world where everyone knows + +Latin and Greek. + +Everyone knows different +kinds of history. + +Everyone is going to be +extremely well versed in + +theology, and these other +things, and MIT graduates, for + +the most part, won't be. + +But he refers to it as courage +to go into that world with + +this new kind of training, +because it will be so rare, it + +certainly was rare +at the time. + +Frankly, it's still rare, as +you'll find what you graduate. + +And that he talks about +a special kind of + +courage that's required. + +And down at the end or that +paragraph, even more, a boy + +who was brought up in a +different way suffers + +somewhat, both in youth and +in manhood, from the mere + +singularity of his education, +though it may have been better + +than the common. + +I found that really interesting +to read. + +I never thought about this +kind of education as + +courageous, or the kind of +people who are educated, as + +taking that on. + +Because you will be an anomaly, +you may not be if you + +go work for a very highly +technical corporation in the + +engineering part. + +But, most corporations, even +the very highly technical + +ones, as you rise up the people +are less and less + +engineering educated, not +to mention in the + +general social world. + +Then he talks a little bit about +the organization that + +Roe mentioned on the +next column. + +A large number of professors +trained in the existing + +methods, hold firm possession +and transmit the traditions + +they inherited. + +And I just thought that was an +interesting word, inherited. + +Because again, he's kind of +trying to overthrow European + +model of inheritance, comes back +to that in a minute, and + +again the American model +is one of earning it. + +And he talks here about how +stodgy these old systems are, + +backed by the reputation of +their authors and the capital + +of their publishers. + +Steadily fed by schools whose +masters are inspired, these + +are the older schools, and +all the so-called learned + +professions, I love that +kind of language. + +Again, I think that's really a +dig at, probably, both the + +clergy and the legal +profession, maybe + +some others as well. + +Also, makes a distinction +between, it's an interesting + +thing about, that none of the +MIT founders have any problem + +teaching languages. + +Which is interesting because one +of the few things that was + +required then, that's not +required now, which I'm not + +sure is the greatest idea, but +it's the living languages + +versus dead languages. + +Especially, then if you don't +read French and German, you + +can't read engineering +literature basically. + +It's not so true today. + +German was, for many years, the +real classic engineering + +literature. + +But just not Latin and Greek. + +And then there's a great line on +the top of the 205 where he + +talks about, again, the +old style educators. + +To have been a school master or +college professor 30 years + +ago only too often makes a man +an unsafe witness in matters + +of education. + +It Is just a great metaphor. + +There are flanges on his mental +wheels which will fit + +only one gauge. + +What is that a reference to? + +It's a railroad analogy. + +So he's using these sort of +technical analogies to make + +his point about the education. + +Then he talks here, again, also +sort of a dis at the kind + +of great professor model +of education. + +In no country is so little +attention paid by parents and + +students to the reputation of +teachers for genius and deep + +learning as in our +own country. + +Faradays, Rumfords, +and Cuviers-- + +these are the famous European +professors-- + +would get very few pupils here +if they're teachings were + +unmethodical and objectless. + +If, in short, they taught under +a bad general system. + +Spasmodic and ill-directed +genius cannot compete in the + +American community with +methodical, careful, teaching + +by less inspired men. + +Very interesting argument +to make. + +I'm not sure if everyone would +agree with that today + +necessarily, but obviously we +don't want to have spasmodic + +and ill-directed directed +genius in + +front of the classroom. + +But, it really is very much +an argument about order in + +education and sort of focus +on what's empirical. + +And I think that's a really +important component of a lot + +of the background here, we +haven't said anything about + +the Enlightenment yet, +in this class. + +Anybody heard that +phrase before? + +Usually associated with the 18th +century, late 17th, most + +of the 18th century, into +the early 19th. + +But, one of the great focuses +of the Enlightenment is + +empirical learning, not just +theorizing, not just the sort + +of platonic philosophy of +working as the ancients + +through a set of reasoned +arguments, but, actually + +gathering data from the world. + +Now, what's interesting about +that, is there's sort of a + +split that you observe where +if you look at someone like + +Louis Agassiz who Roe has +mentioned, the great Harvard + +natural history professor at +the time, very much an + +enlightenment empiricist, in the +sense of Natural History. + +Has anybody been over to +the Harvard Natural + +History Museum lately? + +What kind of a museum is it? + +AUDIENCE: It has +a lot of rocks. + +DAVID KAISER: OK, +a lot of rocks. + +What else? + +AUDIENCE: [INAUDIBLE] + +DAVID KAISER: What? + +Animals. + +It's a kind of, old-fashioned, +glass case museum. + +Right? + +Very typical, not what you'd +find, I was just at the + +Natural History Museum in New +York, which is used to be that + +kind of museum, and still has +pieces of it, but is a very + +different kind of museum. + +But the Harvard museums are sort +of lovely and wonderful + +in this way, but there's cases +and cases of specimens, + +whether they're , plants, or +stuffed animals, what's the + +correct word? + +Taxidermy. + +I brought my daughter there +actually, she liked the + +stuffed animals. + +Animals, plants, geological +specimens, and that's very + +much the kind of natural +historical world that Louis + +Agassiz represented. + +There, the empirical philosophy +was one of + +collecting, ordering the +collection, everything's very + +carefully labeled. + +Very carefully name with a +very fancy Latin name. + +Often then numbered, drawers and +drawers, taking the world + +classifying it, putting +it into a hierarchy. + +You're familiar with the +Linnaean hierarchy of the + +natural world. + +Very much an enlightenment +practice, but slightly more, + +kind of, 18th century version +of it that Agassiz, sort of, + +still represents into +the 19th century. + +Rogers, in his reaction against +that, is in a way, + +kind of even further, more +radical enlightenment. + +What's different about the kind +of world that he would + +think about? + +Let me give you an example that +maybe you could set off. + +I was reading last night an +example of a student who said, + +when I went to work for +Louis Agassiz at + +Harvard as a student. + +Basically, he locked me in a +room with 500 tortoise shells + +and no supporting anything, and +my job was to discern the + +inherent truth of nature that +was collected in those + +tortoise shells. + +What's the kind of world, the +way that Rogers and an MIT + +approach to that problem +might use? + +It's also very empirical, +collecting + +information from the world. + +So it's not that what +he's reacting + +against is not empirical. + +Well first of all, intervention +by active + +experiments. + +You're not just collecting the +world and putting it in glass + +cases, you're often physically +out in it, collectors were + +doing that too, but your making +changes to it, putting + +things on, and also enhancing +your senses by using + +instruments. + +He was a great fan, Rogers, of +new kinds of instrumentation + +and the uses of these kinds +of instruments. + +They might be spectroscopes, +spectrographs, or obviously + +microscopes, but other kinds +of photometers and things. + +And a much more kind of, you +might call it high-tech in a + +way, but also very active +intervention in the world of + +nature, the physical world, the +things you're going into. + +It's not a world of collecting +and classifying, and + +discerning this inherent +underlying truth from. + +It's a world of very active, +and again, as much for the + +students as for the researchers +in his world. + +Which says something about +why he was such + +an admirer of Darwin. + +Yeah, very much so. + +PROFESSOR: It's a world +that's evolving. + +DAVID KAISER: There's a nice +story, which we haven't really + +told about, when Rogers finally +gets the charter for + +MIT, and the war starts. + +And Massachusetts gives him +one year to come up with + +$100,000, which is then later +extended to two years and he + +almost doesn't make it except +for this big gift from + +[? Walker ?]. + +And so he's figured, OK great, +now I'm off and running, I've + +got all this time, the war is +probably going to delay our + +plans a minute I can just +go raise money. + +And the governor comes back to +him and says, oh, and by the + +way, I would really like +you to become the + +inspector of gas in Boston. + +And gas, at the time, is the +new high tech way to light + +your home, and it's a +technological systems, there + +are pipes being run under +the streets in the city. + +But it's very dangerous, +because as still + +today, gas is explosive. + +Probably every few months, a +house in the Boston area blows + +up because of a gas leak. + +And Rogers says, no way, +I can't take the + +time out to do this. + +This is crazy. + +And the governor calls him in +for a one on one, and we don't + +really know what was said, +but he walks out of there + +convinced that he's +going to do it. + +So he takes on this job. + +And soon he finds that the +instruments that he's been + +given to inspect the gas, +probably the quality of the + +gas, and different chemical +composition of it, and the + +different illuminating +capabilities, and maybe + +measure leaks and things +for safety, are + +inadequate for him. + +So he re-engineers, and +re-designs a number of the + +instruments. + +And then he begins to see that +this is actually a very + +valuable thing for him because +he uses the states money to + +buy the latest instrumentation. + +He has very close contact with +industry, and it gives him + +insight into what the latest +kinds of instrumentation + +should be that the students at +MIT, that he would then buy + +for the laboratories as +they're outfitting + +laboratories. + +And it's a nice little story, +partly because of the kind of + +ethos of presidents of MIT doing +national service, or in + +that case they service, which is +something we'll talk about + +later, starts at +the beginning. + +But also because it gets him +out in the world, get him + +involved, and he's very much +a fan of instrumentation. + +Even though you think about +geology in the 1830's and '40s + +is not a ton of instrumentation +associated + +with that, although certainly +there is in surveying. + +It gives you the sense of him as +not simply a scientist, but + +also quite a tinkerer. + +A couple other things to point +out in Elliott essay. + +I found it interesting because +I actually went to Yale as an + +undergrad, and studied +engineering. + +So, I could see why he thought +that was all the wrong model, + +although he praises +it a little bit. + +But, at Yale the school he was +writing about, The Sheffield + +Scientific School, which was +a very famous science and + +engineering school, doesn't +exist anymore. + +It was closed down by the Yale +faculty in the 1950s. + +So, it sort of supports his case +that, that kind of model + +and The Lawrence Scientific +School doesn't existent at + +Harvard either anymore, that +that kind of model is the + +wrong model, and not really +destined survive as a second + +class citizen there. + +But there are a couple other +interesting pieces I + +want to point out. + +He talks on page 215 about, and +this a good reminder, 216 + +on the bottom and the left, +he says, when the American + +University emerges, it will +not be a copy of foreign + +institutions or a +hotbed plant. + +But the slow and natural +outgrowth of American social + +and political habits. + +An expression of the average +aims and ambitions of the + +better educated classes. + +That's interesting because you +think we've been spending all + +of our time you're talking +about the emergence of an + +American university, and the +whole issue vis a vis Harvard. + +What is he referring to there? + +Well, it's worth keeping in +mind that everything we've + +been talking about, so far, is +really about college teaching. + +Harvard College is still Harvard +College at the time. + +I don't know when they changed +their name to Harvard + +University. + +He says the American college +is an institution without a + +parallel, the American +University future tense, will + +be equally original. + +MIT is not a university then +either, some people think it + +isn't today, but I don't think +that's really right. + +But what's the difference +between a college and + +university? + +Simple crude distinction. + +AUDIENCE: [INAUDIBLE] +have more colleges. + +DAVID KAISER: Sorry? + +AUDIENCE: Universities have +[? several ?] colleges. + +DAVID KAISER: Some +do, not all. + +Graduate education. + +So that's actually the first, +does anybody know what the + +first university is in +the United States? + +Johns Hopkins actually. + +And it's founded late 19th, +early 20th century. + +Where you really have the idea +that there's research and + +graduate education, combined +with a college. + +So it's just worth keeping +that in mind, as we move + +forward in time, and MIT does +become a university. + +I mean if you read rankings, +everybody thinks of it as a + +university. + +There are people here still who +say, no it's a technical + +institute, it's not +a university. + +I don't think there's really +too much to be argued for + +that, but arguably MIT only +really became our university, + +in that sense, about +20 years ago. + +It's not an old thing. + +But the graduate model, the +American University that he is + +referring to, is really still +40 years away when he's + +writing this in 1869. + +Then I just thought there was a +great passage on 218, on the + +right column, which also +have an amazing, + +and truly MIT metaphor. + +People who think vaguely about +the difference between a good + +college and a good Polytechnic +school are apt to say, that + +the aim of the college course is +to make a rounded man, with + +all his faculties impartially +developed. + +While it is to express object of +a technical course to make + +a one sided man, the mere + +engineer, chemist, or architect. + +Two truths are supported in +this form of statement. + +First, faculties are +not given by God. + +Sorry, two truths +are suppressed + +in this form statement. + +He was arguing against it. + +First, faculties are not given +by God impartially, to each + +round soul a little +of each power. + +As if the soul were a pill, +which must contain it's due + +proportion of many variance +ingredients. + +To reason about the average +human mind as if it were a + +globe, to be expanded +symmetrically from a center + +outward, is to be betrayed +by metaphor. + +Then I love this. + +A cutting tool, a drill, or an +auger would be a juster symbol + +of the mind. + +If there's not a great +MIT statement, I + +think it's that one. + +PROFESSOR: That's good. + +DAVID KAISER: The natural, best, +and particular quality + +of everybody's mind +should be sacredly + +regarded in his education. + +The division of mental labor, +which is essential in + +civilized communities, in order +that knowledge may grow + +and society improve, demands +this regard to peculiar + +constitution of each mind, +so on and so forth. + +But I think, in some way, that's +also a nice statement + +of the case for MIT, in +an intellectual sense. + +That, not everybody agrees with +it by any stretch, but + +that the model of the mind is +the cutting tool, or the + +drill, or the auger. + +Those of you, all of you, who +are here as undergrads could + +probably feel maybe your mind +as being expected to behave + +that way on a regular basis, +honed finely and sharpened. + +So, I sort of thought +it was worth going + +through some of this. + +It is a difficult +piece to read. + +It's written in this, sort of, +19th century English which can + +be hard to read, but it's +actually a very rich piece, + +and he's got a very strong +opinions, and some of them I + +think are still valuable. + +I did exactly what he thought +was a bad idea. + +Which was I did both a literary +education and + +engineering education +at the same time. + +And given that there's only 24 +hours a day, it's very hard. + +I always my students it's not +hard to do a double major, + +it's just twice the work. + +Which is sort of true, but +inevitably there are + +compromises on either side. + +And the question is, what's +the benefit versus what's + +lost, I think it probably +depends on the individual and + +what you see. + +I think in all this +conversation, right, don't + +forget that the people who run +this world are still more + +Harvard graduates that +MIT graduates. + +OK. + +There is something about that +model, you go over to Harvard + +and you see Teddy Roosevelt, +and Franklin Roosevelt, and + +John F Kennedy, and any number +of US presidents who have been + +Harvard graduates. + +And any number of Harvard +graduates who are in Congress, + +and the Senate, and the Supreme +Court, at any given + +time, far out way, and even +arguably at the top echelons + +of corporations, +MIT graduates. + +And it is worth thinking about +why that is, and why it hasn't + +been different in the last +150 years, that way. + +So what we're reading is the +argument of the people who + +founded MIT, and there's +no question that in the + +scientific and technological +world MIT graduates have been + +great leaders, and actually in +other countries they are more + +likely to be found as presidents +or top political + +leaders than they are +in this country. + +There are many other countries +where engineering is a much + +higher prestige profession, +relatively + +speaking, than it is here. + +And there's reasons for +that, historically. + +Even in France, for example, +the polytechnic graduates + +really are the people who +populate the upper echelons of + +the government. + +That may be changing now +in the last 20 years. + +But it has not been changing +dramatically. + +And so there's a lot of +reasons for that. + +And it's a whole other +conversation to have. + +But it is interesting to think +about what it really takes to + +train people to be leaders and +how well are we doing at that? + +Or how well does Eliot's +model do that? + +I think the general principle +of it really does go back to + +the beginning. + +There has always been a fair +amount of English history, + +management sort of stuff, +languages, again. + +Languages, were considered, +frankly, they probably should + +still be considered, a core part +of a technical education. + +Because we go around as MIT +saying we're training global + +leaders and to do that and not +have a language requirement + +for the undergraduates is a +little bit missing the mark. + +That's my opinion. + +And I'm not someone who's good +with languages at all. + +But many colleges have language +requirements, and it + +probably would be, as someone +pointed out, more Chinese than + +German today. + +That's fine. + +That's the way the +world is going. + +But whatever people +took would surely + +benefit them in the world. + +But the actual school of +humanities and social sciences + +was founded in 1949. + +We just celebrated, well just, +10 years ago, we celebrated + +the 50th anniversary +of the school. + +And the actual eight courses, +I believe, dates from then. + +And that was a product, and +we'll come across this, and + +we'll read the report that the +so-called Lewis Commission + +wrote at the end of World War +II, which really did a lot of + +introspection about what kind +of place is MIT becoming. + +There's all this military +research, there's all this big + +time research on campus. + +What do we really owe +our students? + +And you all know that you have +eight required HASS courses. + +That's quite a bit larger than +most comparable technical + +institutions like Caltech +and RPI, Georgia Tech. + +It's usually lower. + +Certainly overseas at technical +institutions it's + +close to zero. + +And so it is a much bigger +component of it and arguably + +why MIT can consider itself now +among the top ranks of the + +universities. + +If you asked people at MIT +20 years ago, who are our + +competitors? + +They'd say Caltech, Georgia +Tech, RPI, The Royal + +Institute, ETH in Zurich +and so on. + +Now, people will say Harvard, +Yale, Stanford, Princeton. + +And that's really only in the +last 20 years that I know as + +we compete for undergraduates, +most students who say no to + +MIT as undergrads, +where do they go? + +AUDIENCE: [INAUDIBLE] + +Harvard? + +DAVID KAISER: No, Stanford is +the place where you lose the + +most people to. + +So that's a good measure of who +you think you're competing + +against when you accept the +student, and they say no, + +where are they going? + +Far fewer do we lose +to Caltech or + +RPI or Georgia Tech. + +That's true-- + +AUDIENCE: Does that also +have to do with + +the size of the school? + +Like Stanford is a larger +school than Caltech. + +DAVID KAISER: It may well. + +But Stanford is a very different +place from Caltech. + +And so Caltech is a very small +college, as you know. + +It's really, still is, in +many ways a college. + +Other questions? + +Comments from the reading? + +AUDIENCE: [INAUDIBLE] you +mentioned before that + +[INAUDIBLE] college +and universities. + +So how did graduate education +work for people in the 19th + +century here, or how did +it work in Europe? + +Was there a lot of advanced +degrees [? conferred?] + +in physics or what not? + +DAVID KAISER: Well, up into the +1920's, certainly in the + +sciences, if you wanted to get a +Ph.D, you went to Germany or + +to Europe in general, England, +France as well. + +And so if you look at the MIT +faculty in the sciences in the + +teens and '20s, most of them +would probably have European + +educations at the +graduate level. + +That was not just because of +what programs were available + +but also because +of the quality. + +It was really the German +universities in physics that + +were the main thing. + +That begin to change during +the decades before the + +second World War. + +Not least when a lot of European +professors came here. + +But PhDs in engineering, I mean +you don't even see them-- + +MIT did not-- + +I know Vannevar Bush, who +graduated with a Ph.D in 1916, + +I believe, that was MIT's fifth +Ph.D in engineering. + +So a 20th century phenomena +to be sure. + +And, again, engineering was +considered a useful art. + +A Ph.D was considered a high, +scholarly calling. + +And there was a lot of ferment +in and around I want to say + +1890 to 1905 or so. + +University of Chicago +was big in that. + +They hired-- + +it was in Worcester, Clark +University used to have all + +these famous people. + +Robert Goddard was there +for a while and so on. + +And now it's sort of a little +university in a way. + +Why? + +Because the University of +Chicago came in with a lot of + +money and hired away all their +people around 1910, I believe. + +So it's very much a 20th +century thing. + +PROFESSOR: I was thinking about +Warren Lewis who is the + +author of the report David +referred to that established + +the humanities requirement +at MIT. + +He was a chemical engineer. + +And he joined the MIT faculty +around 1910, 1911 after doing + +his Ph.D in Germany. + +And so he's right at the +borderline, I think. + +And he's very much responsible, +in a way, for not + +just revolutionizing +undergraduate education after + +World War II but also being +involved in the establishment + +of doctoral programs at MIT. + +After the arrival of Karl +Compton which is 1930 that-- + +Compton is a physicist who came +to MIT from Princeton and + +comes out of a background at +which doctoral education is + +important to him. + +And so he supports that. + +And then it really grows, I +think, during his presidency + +and then beyond. + +But Lewis is a really +interesting person. + +To think that here's a chemical +engineer who is + +talking so strongly about the +need for humanities education + +at a technical university, +basically, or a technical + +institute is very interesting. + +His granddaughter is a +colleague of ours. + +And I think she's coming to +give a talk about him. + +He's extremely interesting, he's +one of these key people + +at MIT in the 20th century +that had his + +hand on a lot of things. + +DAVID KAISER: You would not find +MIT faculty mostly having + +PhDs until probably +also about 1920. + +Arthur Kennelly is either the +first or one of the first + +electrical engineering +professors here and really + +kind of founds the department. + +He was Bush's advisor. + +Where did he come from? + +He worked in Thomas +Edison's lab. + +I don't believe he had a Ph.D. +And Edison really started this + +model of industrial research +around the 1890s. + +And that was what brought +people back in. + +PROFESSOR: Is that it begins to +happen after World War II + +mainly because so much +important research + +was going on here. + +And big laboratories were +established after World War II + +or during and after World War +II that would have enhanced + +graduate education. + +And as a result, when +you're educating the + +best, you hire them. + +I think that's how it happened, +especially in the + +School of Engineering which has +had a fairly long track + +record of hiring its own. + +If you're producing the best, +you try to hire the best. + +And so I would guess, it's +a guess, I don't have the + +answer, but I would guess that +it's right after World War II + +that you begin to see it. + +DAVID KAISER: So I would give +you a different answer. + +I would guess that +it was earlier. + +Because, again, if you read +all the stuff like in + +Elliott's piece about why the +institution not only needs to + +be what it is, but it needs +to be autonomous. + +I often think of it as a kind +of sign of MIT's arrogance + +like nobody else in the +world is good enough. + +So we have to hire +our own students. + +But you read this sort of stuff, +and you see it's part + +of the culture in that when +they're on the cutting edge of + +either a field or just generally +of the types of + +teaching that you're doing then +you really, it's very + +hard to find people from +elsewhere who are doing that. + +PROFESSOR: So, you would say +it's during the Compton years + +starting in the '30s +or there abouts? + +Or even before that? + +DAVID KAISER: I would imagine +it's before that with hiring + +instructors. + +Not sure about that. + +PROFESSOR: That's interesting. + +DAVID KAISER: Obviously, +it's not so early on. + +But I bet as soon as they become +the right age, it's + +something that gets done. + +It can't be something that's +done that often without some + +traditions behind it. + +A lot of universities +won't do it at all. + +Although, here, I was talking to +someone in Economics, they + +won't hire their own graduates +on the faculty until they've + +gone away for a year or +two, and then they + +will hire them back. + +So, they have a rule that you +cannot come out of your Ph.D + +and join the faculty. + +But you go somewhere else for +a little while and then you + +can come right back. + +And many of their faculty +have PhDs from here. + +PROFESSOR: Not a bad rule. + +Not to my knowledge. + +I don't think there is +a big difference. + +It's basically a play on the +same word, technic but + +preceded by poly means many. + +Basically, it's perhaps +a reference to a + +more diverse approach. + +I don't know. + +You're asking good questions. + +I don't have the answers. + +DAVID KAISER: I think it's +just what you said. + +I think polytechnic, especially +at this time, has a + +little more European +connotation. + +The French schools really are, +they are called polytechnique. + +And they have a certain +way of being that. + +West Point was modeled after +much of, but probably not so + +all of, in that they're +very connected in + +the political system. + +And there's a very sort of well +understood hierarchy for + +the alumni to go through and run +the big bureaucracies and + +the government. + +And there are polytechnic +schools in this country. + +There's California Polytechnic, +there's Brooklyn + +Polytechnic. + +And I think it's really +those are not-- + +there's no meaningful +distinction from them from MIT + +or Caltech. + +It's a kind of term, +connotation. + +PROFESSOR: The other thing +that's relevant to that is + +that Rogers, Charles Eliot, +William Ware in architecture + +all spent time in Europe, +especially in France during + +the founding years of MIT, late +'60s early '70s, looking + +at European universities and, to +a degree, German technical + +institutes. + +And so they're influenced by +these European organizational + +models, if you want +to call it that. + +They don't copy them directly. + +But they surely are looking +and trying to find niches + +where certain parts of the +French educational system fit + +in to the MIT model and +stuff like that. + +They're borrowing. + +They're definitely borrowing +ideas as they should. + +And so those influences are +very much in evidence + +especially during +the early years. + +DAVID KAISER: It's worth +mentioning a phrase that may + +come up which is technocrat. + +Has anybody ever heard +that phrase? + +PROFESSOR: Technocrat. + +DAVID KAISER: You'll hear it +used from time to time. + +And, again, technocracy is a +sort of funny social movement + +from the '20s. + +It's not quite worth +talking about. + +But people do talk about +technocrats when they're + +technically trained people who +are in high positions of + +bureaucracies of one kind or +another and bring a sort of + +technical mentality to running +a large organization. + +And, again, in France, the +technocratic tradition is a + +very old tradition where the +leaders of the polytechnic go + +into the UN, they go into the +various civil bureaucracies, + +and it's the big government +institutions are very much run + +by people with technical +backgrounds. + +It's just not a tradition +in the US that has + +been nearly so much. + +And so we'll come across it when +we talk about the '60s + +like Robert McNamara who ran +the Pentagon during the + +Vietnam War is not an MIT + +graduate, he's not an engineer. + +But he was a very technical +person, very mathematical. + +He was a sort of prototype +technocrat. + +But most leaders of the Pentagon +are not technical, + +most of them are political in +background and have very + +different kinds of skills and +approaches to the world. + +Robert Seamans, who we'll talk +about as well, who was an MIT + +graduate and kind of led the +chief engineer on the Apollo + +program and Secretary of the +Air Force and the first + +Secretary of the Energy was +much more in a kind of + +technocratic role where he had +this kind of background. + +And so you'll see some of +it in the US setting + +but not that much. + +Whereas, again, the +polytechniques and the English + +system doesn't really work +that way either. + +They have their own civil +service system and engineers + +are not particularly high up. + +PROFESSOR: Seamans is one of +these MIT trained engineers, + +comes from an old New England +family as I understand it, but + +who really reached in +the higher echelon. + +He wasn't a politician, but he +ran a number of agencies and + +really was a person of +considerable influence. + +He's only been dead, what? + +Three years, four years? + +DAVID KAISER: One or two. + +Has anyone heard that name? + +Robert Seamans? + +PROFESSOR: Robert +Seamans, aero? + +DAVID KAISER: We'll +come across him. + +PROFESSOR: I'm so sorry he's +not still alive to come and + +visit this class because +he was quite-- + +DAVID KAISER: He's an +interesting story. + +You know we haven't also +mentioned huge issue of social + +class between Harvard and MIT. + +And all of this stuff that we're +reading has buried in it + +the sort of MIT attitude that +Harvard is for elites, and the + +Harvard attitude that MIT +is for vocational + +middle class workers. + +And that runs throughout +all this history. + +And Seamans came from this very +old New England family, + +comes from a family on +the North Shore. + +And he went to Harvard as an +undergrad, in fact he was + +classmates with John +F. Kennedy. + +And I think he maybe took one +course, or he had a friend who + +was doing something at MIT, +and he got really + +interested in MIT. + +And he wanted to come here +for graduate school. + +And he writes in his memoirs +about how his parents said, + +no, no, no, fine boys from our +background don't go to MIT, + +that's not what they do. + +Go, study science at Harvard. + +And he rebelled against that and +really said, no I really + +want to go to MIT. + +And he did amazingly +well here. + +But when time came for him to +advance in his career, he was + +certainly helped by the fact +that he had this advanced + +social background when he +went back to Washington. + +And, again, he was rubbing +elbows with JFK and all the + +senior leadership during +that period. + +And he was socially very +well suited for it. + +So he was a little +bit unusual as an + +engineer during that period. + +PROFESSOR: About every 20 years, +there's a discussion + +that pops up in the MIT +community about why doesn't + +MIT have as many CEOs as Harvard +or Princeton or-- + +and a lot of it centers around +what David has just said is + +that if you look at the social +backgrounds of CEO's, the + +majority of them come out of +backgrounds like Seamans. + +They come out of well-to-do, +socially placed families. + +And so there's this generational +movement that you + +went to Harvard, and you're from +an old family, and you + +have an interest in the company, +you become the CEO at + +some point. + +I think there's a lot +of truth to that. + +And MIT, I think, has been +more of a place that has + +attracted socially mobile +students from middle class + +backgrounds, sometimes working +class backgrounds, + +oftentimes, I think. + +And which is one of the great +things about the place, I + +think, is that-- + +DAVID KAISER: The fraction of +our students who are the first + +generation of their family +to go to college, even + +today, is very high. + +A lot of children +of immigrants-- + +PROFESSOR: I think there's a +very old cultural influence + +involved in all of this in the +sense that during the 19th + +century when we're talking about +the founding of MIT, one + +of the tensions of that period +in the academic world was + +between what groups we'll call +Ancients versus Moderns. + +And the Moderns would be the +type of school like MIT that + +was emphasizing science and +engineering as opposed to the + +Ancients, which were the old +classical colleges teaching + +Greek and Latin and all the +classics and literature and + +things like that. + +There was a lot of +tension there. + +And it also had class +implications that you were + +educating people on the classics +to be gentlemen and + +ladies and things like that. + +Whereas people coming to the +MIT were people that were + +going to go out in the world +and engineer that world or + +pursue science in that world. + +It was a much more utilitarian +oriented disposition, I think, + +which is very American in +many ways because early + +sociologists, I guess you could +call them, people like + +Alexis de Tocqueville, who +visited the United States in + +the 1830's and wrote a very +famous treatise called + +Democracy in America, asks a +lot of questions about what + +makes the United States +what it is. + +Why is it different +from Europe? + +That's one interesting questions +he's asking. + +One of the answers he gives is +that these Americans are so + +utilitarian oriented. + +They are very oriented towards +things that work, things that + +are put to work in society. + +Where as you don't see as +much of that in Europe. + +That was one of his most +important statements about the + +difference between Europe and +the United States, is + +Americans like utility. + +They like things that work. + +They like to get out and tinker +around with stuff. + +He also talks about literacy +in the United States being + +higher than it is in Europe. + +And that being a more literate +nation meant that the United + +States was more apt to be +inventive and pursue areas of + +engineering and science +that others would be + +less involved with. + +DAVID KAISER: It arguably is. + +Which I'm not so +sure, German-- + +PROFESSOR: Maybe. + +DAVID KAISER: I'm not so sure. + +Where it is also is very much +in developing countries even + +in the Middle East and lots of +places where MIT has had an + +influence actually setting +up engineering schools. + +But I'll give you one example, +a lot of wealthy American + +families, they send their +brightest kid to Harvard and + +may become a lawyer or other +place and become a lawyer. + +I used to spend a lot +of time in Turkey. + +And I worked with some people +who were very wealthy and ran + +a lot of big international +trading which is an old + +Turkish kind of profession. + +And these were the very +few, very elite + +families in that country. + +And the people who were my age +who were really the ones + +running and soon to inherit +the business, they had all + +gone to American engineering +schools and + +gotten American MBA's. + +That was their education. + +And I was once at a conference, +and I sat next to + +a guy who was a deputy oil +minister from Iran, which I + +don't meet a lot of +Iranian government + +officials in my work. + +And I was sort of like, this +will be an interesting + +conversation with the two of +us are going to talk about. + +And he was like, you're +from MIT? + +I went to the Iranian Institute +of Technology, it + +was all founded on +MIT's principles. + +And he was incredibly pleased +to meet someone from MIT. + +And sort of like a lot of the +Iranian technocratic class, as + +it were, were trained +as engineers. + +And, again, it has a lot to do +with when countries got on the + +steep part of the development +curve. + +And if it was after World War +II, engineering is generally a + +pretty high status thing +in the field. + +If they're older countries, it's +going to be less so and + +more political or financially +oriented. + +That's a broad generalization, +but it's probably not that-- + +PROFESSOR: It's interesting. + +DAVID KAISER: I have one story +that maybe we should end with + +which was, I went to Yale as an +undergraduate, and I was a + +middle class kid. + +And I remember going +to graduation-- + +has anybody here been +to one of the MIT + +commencements, by the way? + +You'll all go in +a couple years. + +PROFESSOR: I hope you do. + +DAVID KAISER: Hopefully, +you'll all go. + +So when I graduated from Yale, +it was a beautiful May day, + +and it had the feeling of +sort of a garden party. + +Everybody was incredibly well +dressed and sort of very + +polite and well behaved +with the big hats on. + +And you had the sense that these +families had been to + +Yale graduations many +times in the past. + +And it was very sort +of contained. + +And the clapping was +sort of like this. + +When you go as faculty or as +students too to an MIT + +graduation, you march down +Memorial Drive in all the + +regalia, and there's somebody +in the front with the + +processional. + +And you don't really see any of +the parents or any of the + +audience until you turn off +of Memorial Drive into the + +Killian Court, right in +the center there. + +And it has this feeling, +you feel like + +you're at a rock show. + +I mean the parents are +just over the top. + +And there's hundreds of them +outside the gate because they + +only get two tickets per grad, +but they bring like 15 people + +and cousins and aunts and uncles +and grandparents and + +everything. + +And you really have the sense +that it's like a huge + +celebration. + +And, to me, that always +represents that kind of + +different social standing where +it's a really big deal + +for families when their kids +graduate from MIT whether + +they're immigrants +or not because-- + +but it sort of represents +something. + +Sometimes that's a pressure that +the students carry, which + +is not so easy. + +But it really represents +something. + +And it's a big celebration. + +It's not nearly as much +something that generations of + +Smiths have done for all these +years, and it's been expected, + +and we're so proud of +you, kind of thing. + +And you'll see when +you graduate, it + +really feels that way. + +There's 10,000 people there. + +And they're just sort of like +coming out of the woodwork and + +climbing up the trees +and everything. + +And it's a very-- + +to me that's the kind of +ultimate MIT moment where-- + +it's nice as a faculty member, +you remember like what we were + +working for all these years and +I'm sure students as well. + +PROFESSOR: Yeah, it's a good +time, you'll enjoy it. + +Alex will go up to get his +diploma, or whoever, and + +you'll hear people +shouting from the + +audience, that's my Alex. + +And then other students are +going, ah Alex, way to go, + +blah, blah. + +It's all very exciting. + +DAVID KAISER: And they read +every single name of the 2,000 + +or so people who graduate, +which itself is quite an + +accomplishment of logistics +to make that work. + +PROFESSOR: You'll have your +hand shaken either by the + +President of the Provost. + +Isn't that they hand +out every degree? + +So, it's pretty cool. + +When I went to Ohio State, there +were like, I don't know, + +5,000 people on the +football stadium. + +They are all down on the field +and the President gets up, and + +said, I hereby declare +you Bachelor of Art. + +Boom. + +And that was done. + +And everybody goes, OK, let's +get the hell out of here. + +It's very, very different. \ No newline at end of file diff --git a/R-0_0OQ2f4Y.txt b/R-0_0OQ2f4Y.txt new file mode 100644 index 0000000000000000000000000000000000000000..743728a2046a16ea9a0fa5a0cb6149775edc6c8b --- /dev/null +++ b/R-0_0OQ2f4Y.txt @@ -0,0 +1,13519 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start 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MIT courses visit MIT open + + + align:start position:0% +hundreds of MIT courses visit MIT open +courseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu all right so today is our + + align:start position:0% +ocw.mit.edu all right so today is our + + + align:start position:0% +ocw.mit.edu all right so today is our +third and probably final lecture on + + align:start position:0% +third and probably final lecture on + + + align:start position:0% +third and probably final lecture on +approximation algorithms we're going to + + align:start position:0% +approximation algorithms we're going to + + + align:start position:0% +approximation algorithms we're going to +do take a sort of different approach to + + align:start position:0% +do take a sort of different approach to + + + align:start position:0% +do take a sort of different approach to +proving inapproximability uh to + + align:start position:0% +proving inapproximability uh to + + + align:start position:0% +proving inapproximability uh to +optimization problems uh called Gap + + align:start position:0% +optimization problems uh called Gap + + + align:start position:0% +optimization problems uh called Gap +problems and we'll think about Gap + + align:start position:0% +problems and we'll think about Gap + + + align:start position:0% +problems and we'll think about Gap +preserving reductions we will prove + + align:start position:0% +preserving reductions we will prove + + + align:start position:0% +preserving reductions we will prove +along the way optimal lower bound on Max + + align:start position:0% +along the way optimal lower bound on Max + + + align:start position:0% +along the way optimal lower bound on Max +3at and other fun things so let's start + + align:start position:0% +3at and other fun things so let's start + + + align:start position:0% +3at and other fun things so let's start +with what a gap problem + + align:start position:0% + + + + align:start position:0% + +is I haven't actually seen a generic of + + align:start position:0% +is I haven't actually seen a generic of + + + align:start position:0% +is I haven't actually seen a generic of +this so this is new terminology but I + + align:start position:0% +this so this is new terminology but I + + + align:start position:0% +this so this is new terminology but I +think helpful + + align:start position:0% +think helpful + + + align:start position:0% +think helpful +um a gap problem is a is a way of + + align:start position:0% +um a gap problem is a is a way of + + + align:start position:0% +um a gap problem is a is a way of +converting a optimization problem into a + + align:start position:0% +converting a optimization problem into a + + + align:start position:0% +converting a optimization problem into a +decision problem now we already know one + + align:start position:0% +decision problem now we already know one + + + align:start position:0% +decision problem now we already know one +way to do that if you have an NPO + + align:start position:0% +way to do that if you have an NPO + + + align:start position:0% +way to do that if you have an NPO +optimization problem you convert it into + + align:start position:0% +optimization problem you convert it into + + + align:start position:0% +optimization problem you convert it into +the obvious decision problem which is + + align:start position:0% +the obvious decision problem which is + + + align:start position:0% +the obvious decision problem which is +opt at most K uh for the uh minimization + + align:start position:0% +opt at most K uh for the uh minimization + + + align:start position:0% +opt at most K uh for the uh minimization +problem uh that is MP complete but we + + align:start position:0% +problem uh that is MP complete but we + + + align:start position:0% +problem uh that is MP complete but we +want to get something useful from an + + align:start position:0% +want to get something useful from an + + + align:start position:0% +want to get something useful from an +approximability standpoint and and so + + align:start position:0% +approximability standpoint and and so + + + align:start position:0% +approximability standpoint and and so +the idea is here's a different + + align:start position:0% +the idea is here's a different + + + align:start position:0% +the idea is here's a different +problem instead of just deciding whether + + align:start position:0% +problem instead of just deciding whether + + + align:start position:0% +problem instead of just deciding whether +opt is at most + + align:start position:0% + + + + align:start position:0% + +K + + align:start position:0% +K + + + align:start position:0% +K +uh we want to distinguish + + align:start position:0% +uh we want to distinguish + + + align:start position:0% +uh we want to distinguish +between uh opt being at most K + + align:start position:0% +between uh opt being at most K + + + align:start position:0% +between uh opt being at most K +versus opt being at least K Over + + align:start position:0% +versus opt being at least K Over + + + align:start position:0% +versus opt being at least K Over +C for some value C and the analogy here + + align:start position:0% +C for some value C and the analogy here + + + align:start position:0% +C for some value C and the analogy here +is with c approxim algorithm C does not + + align:start position:0% +is with c approxim algorithm C does not + + + align:start position:0% +is with c approxim algorithm C does not +have to be constant despite the name uh + + align:start position:0% +have to be constant despite the name uh + + + align:start position:0% +have to be constant despite the name uh +could be a function of n maybe it's log + + align:start position:0% +could be a function of n maybe it's log + + + align:start position:0% +could be a function of n maybe it's log +n maybe it's n the Epsilon + + align:start position:0% +n maybe it's n the Epsilon + + + align:start position:0% +n maybe it's n the Epsilon +whatever uh so for minimization problem + + align:start position:0% +whatever uh so for minimization problem + + + align:start position:0% +whatever uh so for minimization problem +normally uh did I get this the right way + + align:start position:0% +normally uh did I get this the right way + + + align:start position:0% +normally uh did I get this the right way +sorry that should be C * + + align:start position:0% + + + + align:start position:0% + +k for minimization and for + + align:start position:0% +k for minimization and for + + + align:start position:0% +k for minimization and for +maximization it's going to be the + + align:start position:0% +maximization it's going to be the + + + align:start position:0% +maximization it's going to be the +reverse + + align:start position:0% + + + + align:start position:0% + +and I think I'm going to use strict + + align:start position:0% +and I think I'm going to use strict + + + align:start position:0% +and I think I'm going to use strict +inequality here + + align:start position:0% +inequality here + + + align:start position:0% +inequality here +also okay so minimization there's a gap + + align:start position:0% +also okay so minimization there's a gap + + + align:start position:0% +also okay so minimization there's a gap +here between K and C * K we're imagining + + align:start position:0% +here between K and C * K we're imagining + + + align:start position:0% +here between K and C * K we're imagining +here C is bigger than + + align:start position:0% +here C is bigger than + + + align:start position:0% +here C is bigger than +one uh so distinguishing between being + + align:start position:0% +one uh so distinguishing between being + + + align:start position:0% +one uh so distinguishing between being +less than K being uh at least C * K + + align:start position:0% +less than K being uh at least C * K + + + align:start position:0% +less than K being uh at least C * K +leaves uh a ho and uh the point is you + + align:start position:0% +leaves uh a ho and uh the point is you + + + align:start position:0% +leaves uh a ho and uh the point is you +are promised that your input you have a + + align:start position:0% +are promised that your input you have a + + + align:start position:0% +are promised that your input you have a +question um the second one should it + + align:start position:0% +question um the second one should it + + + align:start position:0% +question um the second one should it +really be C + + align:start position:0% +really be C + + + align:start position:0% +really be C +okay uh sorry + + align:start position:0% + + + + align:start position:0% + +no thank + + align:start position:0% +no thank + + + align:start position:0% +no thank +you c and k sound the same so it's + + align:start position:0% +you c and k sound the same so it's + + + align:start position:0% +you c and k sound the same so it's +always easy to mix them up um cool so + + align:start position:0% +always easy to mix them up um cool so + + + align:start position:0% +always easy to mix them up um cool so +the idea is that you're so in both cases + + align:start position:0% +the idea is that you're so in both cases + + + align:start position:0% +the idea is that you're so in both cases +there's a ratio Gap here of c um and the + + align:start position:0% +there's a ratio Gap here of c um and the + + + align:start position:0% +there's a ratio Gap here of c um and the +idea is that you're promised that your + + align:start position:0% +idea is that you're promised that your + + + align:start position:0% +idea is that you're promised that your +input falls into one of these two + + align:start position:0% +input falls into one of these two + + + align:start position:0% +input falls into one of these two +categories what does it mean to + + align:start position:0% +categories what does it mean to + + + align:start position:0% +categories what does it mean to +distinguish I mean I tell you up front + + align:start position:0% +distinguish I mean I tell you up front + + + align:start position:0% +distinguish I mean I tell you up front +the input either has this property or + + align:start position:0% +the input either has this property or + + + align:start position:0% +the input either has this property or +this property and I want you to decide + + align:start position:0% +this property and I want you to decide + + + align:start position:0% +this property and I want you to decide +which one it is and we'll call these yes + + align:start position:0% +which one it is and we'll call these yes + + + align:start position:0% +which one it is and we'll call these yes +instances and these no + + align:start position:0% +instances and these no + + + align:start position:0% +instances and these no +instances uh normally with the decision + + align:start position:0% +instances uh normally with the decision + + + align:start position:0% +instances uh normally with the decision +problem the no instance is that opt is + + align:start position:0% +problem the no instance is that opt is + + + align:start position:0% +problem the no instance is that opt is +just one bigger or one smaller now we + + align:start position:0% +just one bigger or one smaller now we + + + align:start position:0% +just one bigger or one smaller now we +have a big gap between the no instances + + align:start position:0% +have a big gap between the no instances + + + align:start position:0% +have a big gap between the no instances +and the yes instances we're told that + + align:start position:0% +and the yes instances we're told that + + + align:start position:0% +and the yes instances we're told that +that's true this is called Promise + + align:start position:0% + + + + align:start position:0% + +problem and effectively what that means + + align:start position:0% +problem and effectively what that means + + + align:start position:0% +problem and effectively what that means +is if you're trying to come up with an + + align:start position:0% +is if you're trying to come up with an + + + align:start position:0% +is if you're trying to come up with an +algorithm to solve this decision problem + + align:start position:0% +algorithm to solve this decision problem + + + align:start position:0% +algorithm to solve this decision problem +you don't care what the algorithm does + + align:start position:0% +you don't care what the algorithm does + + + align:start position:0% +you don't care what the algorithm does +if opt happens to fall in between can + + align:start position:0% +if opt happens to fall in between can + + + align:start position:0% +if opt happens to fall in between can +the algorithm can do whatever it want it + + align:start position:0% +the algorithm can do whatever it want it + + + align:start position:0% +the algorithm can do whatever it want it +can output digits of pi in the middle uh + + align:start position:0% +can output digits of pi in the middle uh + + + align:start position:0% +can output digits of pi in the middle uh +as long as when opt is uh most K or + + align:start position:0% +as long as when opt is uh most K or + + + align:start position:0% +as long as when opt is uh most K or +greater than or equal to K it outputs + + align:start position:0% +greater than or equal to K it outputs + + + align:start position:0% +greater than or equal to K it outputs +yes and when opt is at least a factor C + + align:start position:0% +yes and when opt is at least a factor C + + + align:start position:0% +yes and when opt is at least a factor C +away from that it outputs + + align:start position:0% +away from that it outputs + + + align:start position:0% +away from that it outputs +no okay so that's an easier + + align:start position:0% +no okay so that's an easier + + + align:start position:0% +no okay so that's an easier +problem uh and the cool thing + + align:start position:0% +problem uh and the cool thing + + + align:start position:0% +problem uh and the cool thing +is if the C Gap version of a + + align:start position:0% + + + + align:start position:0% + +problem is NP hard + + align:start position:0% + + + + align:start position:0% + +then so is C approximating your original + + align:start position:0% + + + + align:start position:0% + +problem okay so this really is in direct + + align:start position:0% +problem okay so this really is in direct + + + align:start position:0% +problem okay so this really is in direct +analogy to C approximation and so this + + align:start position:0% +analogy to C approximation and so this + + + align:start position:0% +analogy to C approximation and so this +lets us think about an empty hardness + + align:start position:0% +lets us think about an empty hardness + + + align:start position:0% +lets us think about an empty hardness +for decision problem and prove an + + align:start position:0% +for decision problem and prove an + + + align:start position:0% +for decision problem and prove an +inapproximability result this is nice + + align:start position:0% +inapproximability result this is nice + + + align:start position:0% +inapproximability result this is nice +because in the last two lectures we were + + align:start position:0% +because in the last two lectures we were + + + align:start position:0% +because in the last two lectures we were +having to keep track keep track of a lot + + align:start position:0% +having to keep track keep track of a lot + + + align:start position:0% +having to keep track keep track of a lot +more in just defining what + + align:start position:0% +more in just defining what + + + align:start position:0% +more in just defining what +inapproximability meant and uh apx + + align:start position:0% +inapproximability meant and uh apx + + + align:start position:0% +inapproximability meant and uh apx +hardness and so on here it's kind of + + align:start position:0% +hardness and so on here it's kind of + + + align:start position:0% +hardness and so on here it's kind of +back to regular NP hardness now the + + align:start position:0% +back to regular NP hardness now the + + + align:start position:0% +back to regular NP hardness now the +techniques are completely different in + + align:start position:0% +techniques are completely different in + + + align:start position:0% +techniques are completely different in +this world than our older NP hardness + + align:start position:0% +this world than our older NP hardness + + + align:start position:0% +this world than our older NP hardness +proofs but still it's kind of comforting + + align:start position:0% +proofs but still it's kind of comforting + + + align:start position:0% +proofs but still it's kind of comforting +to be back in decision + + align:start position:0% +to be back in decision + + + align:start position:0% +to be back in decision +land uh + + align:start position:0% +land uh + + + align:start position:0% +land uh +cool so uh + + align:start position:0% +cool so uh + + + align:start position:0% +cool so uh +because of this + + align:start position:0% +because of this + + + align:start position:0% +because of this +implication in previous lectures we were + + align:start position:0% +implication in previous lectures we were + + + align:start position:0% +implication in previous lectures we were +just worried about proving + + align:start position:0% +just worried about proving + + + align:start position:0% +just worried about proving +inapproximability + + align:start position:0% +inapproximability + + + align:start position:0% +inapproximability +um but today we're going to be thinking + + align:start position:0% +um but today we're going to be thinking + + + align:start position:0% +um but today we're going to be thinking +about proving that Gap problems are NP + + align:start position:0% +about proving that Gap problems are NP + + + align:start position:0% +about proving that Gap problems are NP +hard or some other kind of hardness um + + align:start position:0% +hard or some other kind of hardness um + + + align:start position:0% +hard or some other kind of hardness um +this is a stronger type of result so in + + align:start position:0% +this is a stronger type of result so in + + + align:start position:0% +this is a stronger type of result so in +general in approximability is kind of + + align:start position:0% +general in approximability is kind of + + + align:start position:0% +general in approximability is kind of +what you care about from the algorithmic + + align:start position:0% +what you care about from the algorithmic + + + align:start position:0% +what you care about from the algorithmic +standpoint but Gap results saying that + + align:start position:0% +standpoint but Gap results saying that + + + align:start position:0% +standpoint but Gap results saying that +hey your problem is hard even if you + + align:start position:0% +hey your problem is hard even if you + + + align:start position:0% +hey your problem is hard even if you +have this huge gap between uh the yes + + align:start position:0% +have this huge gap between uh the yes + + + align:start position:0% +have this huge gap between uh the yes +instances and the no instances that's + + align:start position:0% +instances and the no instances that's + + + align:start position:0% +instances and the no instances that's +also sort of of independent interest + + align:start position:0% +also sort of of independent interest + + + align:start position:0% +also sort of of independent interest +more about the structure of the problem + + align:start position:0% +more about the structure of the problem + + + align:start position:0% +more about the structure of the problem +uh but one implies the other so this is + + align:start position:0% +uh but one implies the other so this is + + + align:start position:0% +uh but one implies the other so this is +the stronger type of thing to go + + align:start position:0% +the stronger type of thing to go + + + align:start position:0% +the stronger type of thing to go +for uh the other the Practical reason to + + align:start position:0% +for uh the other the Practical reason to + + + align:start position:0% +for uh the other the Practical reason to +care about this stuff is that Gap uh + + align:start position:0% +care about this stuff is that Gap uh + + + align:start position:0% +care about this stuff is that Gap uh +this Gap idea lets you get stronger in + + align:start position:0% +this Gap idea lets you get stronger in + + + align:start position:0% +this Gap idea lets you get stronger in +approximability results the the factor C + + align:start position:0% +approximability results the the factor C + + + align:start position:0% +approximability results the the factor C +you get by thinking about gaps in + + align:start position:0% +you get by thinking about gaps in + + + align:start position:0% +you get by thinking about gaps in +practice seems to be larger than the + + align:start position:0% +practice seems to be larger than the + + + align:start position:0% +practice seems to be larger than the +gaps you get by um L reductions and + + align:start position:0% +gaps you get by um L reductions and + + + align:start position:0% +gaps you get by um L reductions and +things + + align:start position:0% +things + + + align:start position:0% +things +so let me tell you about one other type + + align:start position:0% +so let me tell you about one other type + + + align:start position:0% +so let me tell you about one other type +of Gap problem this is a standard + + align:start position:0% +of Gap problem this is a standard + + + align:start position:0% +of Gap problem this is a standard +one a little bit more + + align:start position:0% + + + + align:start position:0% + +precise uh consider Max sat pick your + + align:start position:0% +precise uh consider Max sat pick your + + + align:start position:0% +precise uh consider Max sat pick your +favorite version of maxat or Max CSP was + + align:start position:0% +favorite version of maxat or Max CSP was + + + align:start position:0% +favorite version of maxat or Max CSP was +the general form where you could have + + align:start position:0% +the general form where you could have + + + align:start position:0% +the general form where you could have +any type of clause uh instead of just a + + align:start position:0% +any type of clause uh instead of just a + + + align:start position:0% +any type of clause uh instead of just a +c Gap we will Define slightly more + + align:start position:0% +c Gap we will Define slightly more + + + align:start position:0% +c Gap we will Define slightly more +precisely an AB gap which is to + + align:start position:0% + + + + align:start position:0% + +distinguish + + align:start position:0% +distinguish + + + align:start position:0% +distinguish +between + + align:start position:0% + + + + align:start position:0% + +uh opt is less than a times the number + + align:start position:0% +uh opt is less than a times the number + + + align:start position:0% +uh opt is less than a times the number +of + + align:start position:0% + + + + align:start position:0% + +Clauses and opt is at least B times the + + align:start position:0% +Clauses and opt is at least B times the + + + align:start position:0% +Clauses and opt is at least B times the +number of + + align:start position:0% + + + + align:start position:0% + +Clauses okay so uh whereas here sort of + + align:start position:0% +Clauses okay so uh whereas here sort of + + + align:start position:0% +Clauses okay so uh whereas here sort of +everything was relative to some put K + + align:start position:0% +everything was relative to some put K + + + align:start position:0% +everything was relative to some put K +that you want to decide about here + + align:start position:0% +that you want to decide about here + + + align:start position:0% +that you want to decide about here +there's uh with sat there's a kind of + + align:start position:0% +there's uh with sat there's a kind of + + + align:start position:0% +there's uh with sat there's a kind of +absolute notion of what you'd like to + + align:start position:0% +absolute notion of what you'd like to + + + align:start position:0% +absolute notion of what you'd like to +achieve which is that you satisfy + + align:start position:0% +achieve which is that you satisfy + + + align:start position:0% +achieve which is that you satisfy +everything all clauses are true so + + align:start position:0% +everything all clauses are true so + + + align:start position:0% +everything all clauses are true so +typically we'll think about B being + + align:start position:0% + + + + align:start position:0% + +one uh and so you're distinguishing + + align:start position:0% +one uh and so you're distinguishing + + + align:start position:0% +one uh and so you're distinguishing +between a satisfiable instance where all + + align:start position:0% +between a satisfiable instance where all + + + align:start position:0% +between a satisfiable instance where all +clauses are satisfied and something + + align:start position:0% +clauses are satisfied and something + + + align:start position:0% +clauses are satisfied and something +that's very unsatisfiable there's some + + align:start position:0% +that's very unsatisfiable there's some + + + align:start position:0% +that's very unsatisfiable there's some +uh usually constant fraction uh + + align:start position:0% +uh usually constant fraction uh + + + align:start position:0% +uh usually constant fraction uh +unsatisfiable + + align:start position:0% +unsatisfiable + + + align:start position:0% +unsatisfiable +Clauses okay so that lets us be this is + + align:start position:0% +Clauses okay so that lets us be this is + + + align:start position:0% +Clauses okay so that lets us be this is +we need need this level of precision uh + + align:start position:0% +we need need this level of precision uh + + + align:start position:0% +we need need this level of precision uh +thinking about when you're WR up against + + align:start position:0% +thinking about when you're WR up against + + + align:start position:0% +thinking about when you're WR up against +100% satisfied versus like 1% satisfied + + align:start position:0% +100% satisfied versus like 1% satisfied + + + align:start position:0% +100% satisfied versus like 1% satisfied +or something like that or 1% + + align:start position:0% +or something like that or 1% + + + align:start position:0% +or something like that or 1% +satisfiable okay uh do we use the same + + align:start position:0% +satisfiable okay uh do we use the same + + + align:start position:0% +satisfiable okay uh do we use the same +notation for one ER or only for the ones + + align:start position:0% +notation for one ER or only for the ones + + + align:start position:0% +notation for one ER or only for the ones +problem like the maximum number of ones + + align:start position:0% +problem like the maximum number of ones + + + align:start position:0% +problem like the maximum number of ones +I haven't seen it but yeah it's a good + + align:start position:0% +I haven't seen it but yeah it's a good + + + align:start position:0% +I haven't seen it but yeah it's a good +question s certainly valid to do it for + + align:start position:0% +question s certainly valid to do it for + + + align:start position:0% +question s certainly valid to do it for +uh we will see it for one other type of + + align:start position:0% +uh we will see it for one other type of + + + align:start position:0% +uh we will see it for one other type of +problem I mean for any problem if you + + align:start position:0% +problem I mean for any problem if you + + + align:start position:0% +problem I mean for any problem if you +can Define some absolute notion of how + + align:start position:0% +can Define some absolute notion of how + + + align:start position:0% +can Define some absolute notion of how +much you'd like to get you can always + + align:start position:0% +much you'd like to get you can always + + + align:start position:0% +much you'd like to get you can always +measure relative to that and Define a + + align:start position:0% +measure relative to that and Define a + + + align:start position:0% +measure relative to that and Define a +this kind of ab Gap + + align:start position:0% +this kind of ab Gap + + + align:start position:0% +this kind of ab Gap +problem cool uh all right so how do we + + align:start position:0% +problem cool uh all right so how do we + + + align:start position:0% +problem cool uh all right so how do we +get these + + align:start position:0% +get these + + + align:start position:0% +get these +gaps uh there's two well maybe three + + align:start position:0% +gaps uh there's two well maybe three + + + align:start position:0% +gaps uh there's two well maybe three +ways I guess + + align:start position:0% + + + + align:start position:0% + +uh in general we're going to use + + align:start position:0% +uh in general we're going to use + + + align:start position:0% +uh in general we're going to use +reductions like always uh and you could + + align:start position:0% +reductions like always uh and you could + + + align:start position:0% +reductions like always uh and you could +start from no Gap and make a gap or + + align:start position:0% +start from no Gap and make a gap or + + + align:start position:0% +start from no Gap and make a gap or +start from from a gap of additive one + + align:start position:0% +start from from a gap of additive one + + + align:start position:0% +start from from a gap of additive one +and turn it into a big multiplicative + + align:start position:0% +and turn it into a big multiplicative + + + align:start position:0% +and turn it into a big multiplicative +Gap that will be Gap producing + + align:start position:0% +Gap that will be Gap producing + + + align:start position:0% +Gap that will be Gap producing +reductions you could start with some Gap + + align:start position:0% +reductions you could start with some Gap + + + align:start position:0% +reductions you could start with some Gap +and then make it bigger that's a gap + + align:start position:0% +and then make it bigger that's a gap + + + align:start position:0% +and then make it bigger that's a gap +amplifying reduction or you could just + + align:start position:0% +amplifying reduction or you could just + + + align:start position:0% +amplifying reduction or you could just +start with a gap and try to preserve it + + align:start position:0% +start with a gap and try to preserve it + + + align:start position:0% +start with a gap and try to preserve it +that would be Gap preserving reductions + + align:start position:0% +that would be Gap preserving reductions + + + align:start position:0% +that would be Gap preserving reductions +in general if you once you have some Gap + + align:start position:0% +in general if you once you have some Gap + + + align:start position:0% +in general if you once you have some Gap +you try to keep it or make it bigger to + + align:start position:0% +you try to keep it or make it bigger to + + + align:start position:0% +you try to keep it or make it bigger to +get stronger hardness for your problem + + align:start position:0% +get stronger hardness for your problem + + + align:start position:0% +get stronger hardness for your problem +um so the idea with a gap producing + + align:start position:0% +um so the idea with a gap producing + + + align:start position:0% +um so the idea with a gap producing +reduction is that you have no assumption + + align:start position:0% +reduction is that you have no assumption + + + align:start position:0% +reduction is that you have no assumption +about your starting problem in general + + align:start position:0% +about your starting problem in general + + + align:start position:0% +about your starting problem in general +reduction we're going from some problem + + align:start position:0% +reduction we're going from some problem + + + align:start position:0% +reduction we're going from some problem +a to some problem B and what we would + + align:start position:0% +a to some problem B and what we would + + + align:start position:0% +a to some problem B and what we would +like is that the output instance uh to + + align:start position:0% +like is that the output instance uh to + + + align:start position:0% +like is that the output instance uh to +problem + + align:start position:0% +problem + + + align:start position:0% +problem +B uh the output of the reduction + + align:start position:0% +B uh the output of the reduction + + + align:start position:0% +B uh the output of the reduction +has uh let's say opt equal to K or uh + + align:start position:0% +has uh let's say opt equal to K or uh + + + align:start position:0% +has uh let's say opt equal to K or uh +for a minimization problem opt bigger + + align:start position:0% +for a minimization problem opt bigger + + + align:start position:0% +for a minimization problem opt bigger +than C * k + + align:start position:0% +than C * k + + + align:start position:0% +than C * k +and for a maximization problem opt less + + align:start position:0% +and for a maximization problem opt less + + + align:start position:0% +and for a maximization problem opt less +than K Over + + align:start position:0% + + + + align:start position:0% + +C uh so that's just saying we have a gap + + align:start position:0% +C uh so that's just saying we have a gap + + + align:start position:0% +C uh so that's just saying we have a gap +in the output we assume nothing about + + align:start position:0% +in the output we assume nothing about + + + align:start position:0% +in the output we assume nothing about +the input instance that would be a gap + + align:start position:0% +the input instance that would be a gap + + + align:start position:0% +the input instance that would be a gap +producing reduction now we have seen + + align:start position:0% +producing reduction now we have seen + + + align:start position:0% +producing reduction now we have seen +some of these + + align:start position:0% +some of these + + + align:start position:0% +some of these +before um or at least mention them one + + align:start position:0% +before um or at least mention them one + + + align:start position:0% +before um or at least mention them one +of them this is from lecture three I + + align:start position:0% +of them this is from lecture three I + + + align:start position:0% +of them this is from lecture three I +think for Tetris we proved MP hardness + + align:start position:0% +think for Tetris we proved MP hardness + + + align:start position:0% +think for Tetris we proved MP hardness +which was this three partition reduction + + align:start position:0% +which was this three partition reduction + + + align:start position:0% +which was this three partition reduction +and the idea is that if you could + + align:start position:0% +and the idea is that if you could + + + align:start position:0% +and the idea is that if you could +satisfy that and open this thing then + + align:start position:0% +satisfy that and open this thing then + + + align:start position:0% +satisfy that and open this thing then +you could get a zillion points down here + + align:start position:0% +you could get a zillion points down here + + + align:start position:0% +you could get a zillion points down here +here uh and most of the instances down + + align:start position:0% +here uh and most of the instances down + + + align:start position:0% +here uh and most of the instances down +here we squeeze this down to like an N + + align:start position:0% +here we squeeze this down to like an N + + + align:start position:0% +here we squeeze this down to like an N +the Epsilon that's still hard and so n + + align:start position:0% +the Epsilon that's still hard and so n + + + align:start position:0% +the Epsilon that's still hard and so n +1us Epsilon of the instances down here + + align:start position:0% +1us Epsilon of the instances down here + + + align:start position:0% +1us Epsilon of the instances down here +uh and you know you're given a ton of + + align:start position:0% +uh and you know you're given a ton of + + + align:start position:0% +uh and you know you're given a ton of +pieces uh to fill into space get lots of + + align:start position:0% +pieces uh to fill into space get lots of + + + align:start position:0% +pieces uh to fill into space get lots of +points if the answer was no here then + + align:start position:0% +points if the answer was no here then + + + align:start position:0% +points if the answer was no here then +you won't get those points and so opt is + + align:start position:0% +you won't get those points and so opt is + + + align:start position:0% +you won't get those points and so opt is +very small at most say n to the Epsilon + + align:start position:0% +very small at most say n to the Epsilon + + + align:start position:0% +very small at most say n to the Epsilon +uh if you can solve this instance we + + align:start position:0% +uh if you can solve this instance we + + + align:start position:0% +uh if you can solve this instance we +have a yes instance in the input then we + + align:start position:0% +have a yes instance in the input then we + + + align:start position:0% +have a yes instance in the input then we +get uh like end points so the Gap there + + align:start position:0% +get uh like end points so the Gap there + + + align:start position:0% +get uh like end points so the Gap there +is n the 1us + + align:start position:0% + + + + align:start position:0% + +Epsilon so Tetris the tetris reduction + + align:start position:0% +Epsilon so Tetris the tetris reduction + + + align:start position:0% +Epsilon so Tetris the tetris reduction +we assumed nothing about the three + + align:start position:0% +we assumed nothing about the three + + + align:start position:0% +we assumed nothing about the three +partition instance it was just yes or no + + align:start position:0% +partition instance it was just yes or no + + + align:start position:0% +partition instance it was just yes or no +and we produced an instance that had a a + + align:start position:0% +and we produced an instance that had a a + + + align:start position:0% +and we produced an instance that had a a +gap of n 1 minus Epsilon we could set + + align:start position:0% +gap of n 1 minus Epsilon we could set + + + align:start position:0% +gap of n 1 minus Epsilon we could set +Epsilon to any constant we want bigger + + align:start position:0% +Epsilon to any constant we want bigger + + + align:start position:0% +Epsilon to any constant we want bigger +than + + align:start position:0% +than + + + align:start position:0% +than +zero okay uh we also mentioned another + + align:start position:0% +zero okay uh we also mentioned another + + + align:start position:0% +zero okay uh we also mentioned another +such reduction and in general for a lot + + align:start position:0% +such reduction and in general for a lot + + + align:start position:0% +such reduction and in general for a lot +of games and puzzles you can do this + + align:start position:0% +of games and puzzles you can do this + + + align:start position:0% +of games and puzzles you can do this +it's sort of an All or Nothing deal and + + align:start position:0% +it's sort of an All or Nothing deal and + + + align:start position:0% +it's sort of an All or Nothing deal and +GAP producing reduction is a way to + + align:start position:0% +GAP producing reduction is a way to + + + align:start position:0% +GAP producing reduction is a way to +formalize + + align:start position:0% +formalize + + + align:start position:0% +formalize +that uh another problem we talked about + + align:start position:0% +that uh another problem we talked about + + + align:start position:0% +that uh another problem we talked about +last class I believe was non-metric tsp + + align:start position:0% +last class I believe was non-metric tsp + + + align:start position:0% +last class I believe was non-metric tsp +I just give you uh complete graph every + + align:start position:0% +I just give you uh complete graph every + + + align:start position:0% +I just give you uh complete graph every +Edge has some number on it that's the + + align:start position:0% +Edge has some number on it that's the + + + align:start position:0% +Edge has some number on it that's the +length of that edge you want to find a + + align:start position:0% +length of that edge you want to find a + + + align:start position:0% +length of that edge you want to find a +tsp tour of minimum total length this is + + align:start position:0% +tsp tour of minimum total length this is + + + align:start position:0% +tsp tour of minimum total length this is +really hard to approximate because uh + + align:start position:0% +really hard to approximate because uh + + + align:start position:0% +really hard to approximate because uh +depending on your model you can use uh + + align:start position:0% +depending on your model you can use uh + + + align:start position:0% +depending on your model you can use uh +let's say Edge + + align:start position:0% +let's say Edge + + + align:start position:0% +let's say Edge +weights in uh to be really annoying + + align:start position:0% +weights in uh to be really annoying + + + align:start position:0% +weights in uh to be really annoying +would be 0 comma 1 and if I'm given a + + align:start position:0% +would be 0 comma 1 and if I'm given a + + + align:start position:0% +would be 0 comma 1 and if I'm given a +hamiltonicity instance wherever there's + + align:start position:0% +hamiltonicity instance wherever there's + + + align:start position:0% +hamiltonicity instance wherever there's +an edge I put a weight of zero wherever + + align:start position:0% +an edge I put a weight of zero wherever + + + align:start position:0% +an edge I put a weight of zero wherever +there's not an edge I put weight of one + + align:start position:0% +there's not an edge I put weight of one + + + align:start position:0% +there's not an edge I put weight of one +and then if the input graph was + + align:start position:0% +and then if the input graph was + + + align:start position:0% +and then if the input graph was +hamiltonian as a yes instance then the + + align:start position:0% +hamiltonian as a yes instance then the + + + align:start position:0% +hamiltonian as a yes instance then the +output thing will have a tour of length + + align:start position:0% +output thing will have a tour of length + + + align:start position:0% +output thing will have a tour of length +zero and if the input was not + + align:start position:0% +zero and if the input was not + + + align:start position:0% +zero and if the input was not +hamiltonian then the output will have + + align:start position:0% +hamiltonian then the output will have + + + align:start position:0% +hamiltonian then the output will have +weight n ratio between n and zero is + + align:start position:0% +weight n ratio between n and zero is + + + align:start position:0% +weight n ratio between n and zero is +Infinity so this is an infinite Gap + + align:start position:0% +Infinity so this is an infinite Gap + + + align:start position:0% +Infinity so this is an infinite Gap +creation if you allow weights of zero if + + align:start position:0% +creation if you allow weights of zero if + + + align:start position:0% +creation if you allow weights of zero if +you say Zero's cheating uh which we did + + align:start position:0% +you say Zero's cheating uh which we did + + + align:start position:0% +you say Zero's cheating uh which we did +uh and some papers do uh you can instead + + align:start position:0% +uh and some papers do uh you can instead + + + align:start position:0% +uh and some papers do uh you can instead +do one and Infinity uh where Infinity is + + align:start position:0% +do one and Infinity uh where Infinity is + + + align:start position:0% +do one and Infinity uh where Infinity is +the largest rep uh representable number + + align:start position:0% +the largest rep uh representable number + + + align:start position:0% +the largest rep uh representable number +so that's going to be something like 2 + + align:start position:0% +so that's going to be something like 2 + + + align:start position:0% +so that's going to be something like 2 +to the N if you allow usual binary + + align:start position:0% +to the N if you allow usual binary + + + align:start position:0% +to the N if you allow usual binary +encodings of numbers uh if you if you + + align:start position:0% +encodings of numbers uh if you if you + + + align:start position:0% +encodings of numbers uh if you if you +don't the the PB case then that would be + + align:start position:0% +don't the the PB case then that would be + + + align:start position:0% +don't the the PB case then that would be +you know end to some constant but you + + align:start position:0% +you know end to some constant but you + + + align:start position:0% +you know end to some constant but you +get a big gap in any case right so you + + align:start position:0% +get a big gap in any case right so you + + + align:start position:0% +get a big gap in any case right so you +get some Gap equals + + align:start position:0% +get some Gap equals + + + align:start position:0% +get some Gap equals +huge okay so these are kind of trivial + + align:start position:0% +huge okay so these are kind of trivial + + + align:start position:0% +huge okay so these are kind of trivial +senses of inapproximability but hey + + align:start position:0% +senses of inapproximability but hey + + + align:start position:0% +senses of inapproximability but hey +that's one way to do it um what we're + + align:start position:0% +that's one way to do it um what we're + + + align:start position:0% +that's one way to do it um what we're +going to talk about today are uh other + + align:start position:0% +going to talk about today are uh other + + + align:start position:0% +going to talk about today are uh other +known ways to get Gap production uh that + + align:start position:0% +known ways to get Gap production uh that + + + align:start position:0% +known ways to get Gap production uh that +are really cool and more broadly useful + + align:start position:0% +are really cool and more broadly useful + + + align:start position:0% +are really cool and more broadly useful +this is useful when you have a sort of + + align:start position:0% +this is useful when you have a sort of + + + align:start position:0% +this is useful when you have a sort of +All or Nothing problem a lot of the time + + align:start position:0% +All or Nothing problem a lot of the time + + + align:start position:0% +All or Nothing problem a lot of the time +it's not so clear there's a constant + + align:start position:0% +it's not so clear there's a constant + + + align:start position:0% +it's not so clear there's a constant +Factor approximation uh so some giant + + align:start position:0% +Factor approximation uh so some giant + + + align:start position:0% +Factor approximation uh so some giant +Gap like this isn't going to be possible + + align:start position:0% +Gap like this isn't going to be possible + + + align:start position:0% +Gap like this isn't going to be possible +but still gaps are + + align:start position:0% +but still gaps are + + + align:start position:0% +but still gaps are +possible uh + + align:start position:0% +possible uh + + + align:start position:0% +possible uh +now uh an important part of the story + + align:start position:0% +now uh an important part of the story + + + align:start position:0% +now uh an important part of the story +here is the the PCP theorem so this is + + align:start position:0% +here is the the PCP theorem so this is + + + align:start position:0% +here is the the PCP theorem so this is +not about drugs this is + + align:start position:0% +not about drugs this is + + + align:start position:0% +not about drugs this is +about + + align:start position:0% + + + + align:start position:0% + +uh another complexity + + align:start position:0% +uh another complexity + + + align:start position:0% +uh another complexity +class um and the complexity class is + + align:start position:0% +class um and the complexity class is + + + align:start position:0% +class um and the complexity class is +normally written PCP of order log n + + align:start position:0% +normally written PCP of order log n + + + align:start position:0% +normally written PCP of order log n +comma order one I'm going to simplify + + align:start position:0% +comma order one I'm going to simplify + + + align:start position:0% +comma order one I'm going to simplify +this to just PCP as the class the other + + align:start position:0% +this to just PCP as the class the other + + + align:start position:0% +this to just PCP as the class the other +Notions make sense here although + + align:start position:0% +Notions make sense here although + + + align:start position:0% +Notions make sense here although +parameters don't turn out to matter too + + align:start position:0% +parameters don't turn out to matter too + + + align:start position:0% +parameters don't turn out to matter too +much and it's rather lengthy to write + + align:start position:0% +much and it's rather lengthy to write + + + align:start position:0% +much and it's rather lengthy to write +that every time so I'm just going to + + align:start position:0% +that every time so I'm just going to + + + align:start position:0% +that every time so I'm just going to +write PCP uh let me first tell you what + + align:start position:0% +write PCP uh let me first tell you what + + + align:start position:0% +write PCP uh let me first tell you what +this class is about uh briefly and then + + align:start position:0% +this class is about uh briefly and then + + + align:start position:0% +this class is about uh briefly and then +we'll see why it's directly related to + + align:start position:0% +we'll see why it's directly related to + + + align:start position:0% +we'll see why it's directly related to +Gap problems and where a lot of these + + align:start position:0% +Gap problems and where a lot of these + + + align:start position:0% +Gap problems and where a lot of these +Gap producing reductions come from so uh + + align:start position:0% +Gap producing reductions come from so uh + + + align:start position:0% +Gap producing reductions come from so uh +PCP stands for probabilistically + + align:start position:0% +PCP stands for probabilistically + + + align:start position:0% +PCP stands for probabilistically +checkable + + align:start position:0% + + + + align:start position:0% + +proof the checkable proof refers to uh + + align:start position:0% +proof the checkable proof refers to uh + + + align:start position:0% +proof the checkable proof refers to uh +NP NP every yes instance has a checkable + + align:start position:0% +NP NP every yes instance has a checkable + + + align:start position:0% +NP NP every yes instance has a checkable +proof that the answer is yes uh + + align:start position:0% +proof that the answer is yes uh + + + align:start position:0% +proof that the answer is yes uh +probabilistically checkable means you + + align:start position:0% +probabilistically checkable means you + + + align:start position:0% +probabilistically checkable means you +can check it even faster with high + + align:start position:0% +can check it even faster with high + + + align:start position:0% +can check it even faster with high +probability so normally to check a proof + + align:start position:0% +probability so normally to check a proof + + + align:start position:0% +probability so normally to check a proof +we take polinomial time in NP + + align:start position:0% +we take polinomial time in NP + + + align:start position:0% +we take polinomial time in NP +uh here we want to achieve like constant + + align:start position:0% +uh here we want to achieve like constant + + + align:start position:0% +uh here we want to achieve like constant +time that's the main idea that can't be + + align:start position:0% +time that's the main idea that can't be + + + align:start position:0% +time that's the main idea that can't be +done perfectly but you can do it + + align:start position:0% +done perfectly but you can do it + + + align:start position:0% +done perfectly but you can do it +correctly with high probability so in + + align:start position:0% +correctly with high probability so in + + + align:start position:0% +correctly with high probability so in +general in a problem in PCP has + + align:start position:0% +general in a problem in PCP has + + + align:start position:0% +general in a problem in PCP has +certificates of polinomial length just + + align:start position:0% +certificates of polinomial length just + + + align:start position:0% +certificates of polinomial length just +like + + align:start position:0% + + + + align:start position:0% + +NP and we have an algorithm for checking + + align:start position:0% +NP and we have an algorithm for checking + + + align:start position:0% +NP and we have an algorithm for checking +certificates + + align:start position:0% + + + + align:start position:0% + +which is + + align:start position:0% +which is + + + align:start position:0% +which is +given uh + + align:start position:0% +given uh + + + align:start position:0% +given uh +certificate and it's given uh order log + + align:start position:0% +certificate and it's given uh order log + + + align:start position:0% +certificate and it's given uh order log +n Bits of + + align:start position:0% + + + + align:start position:0% + +Randomness that's what this first + + align:start position:0% +Randomness that's what this first + + + align:start position:0% +Randomness that's what this first +parameter refers to is how much + + align:start position:0% +parameter refers to is how much + + + align:start position:0% +parameter refers to is how much +Randomness the algorithm's given so we + + align:start position:0% +Randomness the algorithm's given so we + + + align:start position:0% +Randomness the algorithm's given so we +restrict the amount of Randomness to + + align:start position:0% +restrict the amount of Randomness to + + + align:start position:0% +restrict the amount of Randomness to +fairly small + + align:start position:0% +fairly small + + + align:start position:0% +fairly small +amount and it should tell you whether + + align:start position:0% +amount and it should tell you whether + + + align:start position:0% +amount and it should tell you whether +the instance is a yes instance or a no + + align:start position:0% +the instance is a yes instance or a no + + + align:start position:0% +the instance is a yes instance or a no +instance uh in some sense if you're + + align:start position:0% +instance uh in some sense if you're + + + align:start position:0% +instance uh in some sense if you're +given the right certificate so uh in + + align:start position:0% +given the right certificate so uh in + + + align:start position:0% +given the right certificate so uh in +particular if the instance was the S + + align:start position:0% +particular if the instance was the S + + + align:start position:0% +particular if the instance was the S +instance so this is back to decision + + align:start position:0% +instance so this is back to decision + + + align:start position:0% +instance so this is back to decision +problems right just like NP there's no + + align:start position:0% +problems right just like NP there's no + + + align:start position:0% +problems right just like NP there's no +optimization here but we're going to + + align:start position:0% +optimization here but we're going to + + + align:start position:0% +optimization here but we're going to +apply this to Gap problems and that will + + align:start position:0% +apply this to Gap problems and that will + + + align:start position:0% +apply this to Gap problems and that will +relate us to + + align:start position:0% +relate us to + + + align:start position:0% +relate us to +optimization uh so + + align:start position:0% + + + + align:start position:0% + +let's say uh there's no error on yes + + align:start position:0% +let's say uh there's no error on yes + + + align:start position:0% +let's say uh there's no error on yes +inst instances although you could relax + + align:start position:0% +inst instances although you could relax + + + align:start position:0% +inst instances although you could relax +that it won't make a big difference so + + align:start position:0% +that it won't make a big difference so + + + align:start position:0% +that it won't make a big difference so +if you give if you have a yes instance + + align:start position:0% +if you give if you have a yes instance + + + align:start position:0% +if you give if you have a yes instance +and you give the right certificate so + + align:start position:0% +and you give the right certificate so + + + align:start position:0% +and you give the right certificate so +this is for some + + align:start position:0% + + + + align:start position:0% + +certificate uh the algorithm is + + align:start position:0% +certificate uh the algorithm is + + + align:start position:0% +certificate uh the algorithm is +guaranteed to say yes so no error there + + align:start position:0% +guaranteed to say yes so no error there + + + align:start position:0% +guaranteed to say yes so no error there +uh where we add some slack is if there's + + align:start position:0% +uh where we add some slack is if there's + + + align:start position:0% +uh where we add some slack is if there's +a no + + align:start position:0% +a no + + + align:start position:0% +a no +instance now normally in NP for a no + + align:start position:0% +instance now normally in NP for a no + + + align:start position:0% +instance now normally in NP for a no +instance there is no correct + + align:start position:0% +instance there is no correct + + + align:start position:0% +instance there is no correct +certificate uh now the algorithm will + + align:start position:0% +certificate uh now the algorithm will + + + align:start position:0% +certificate uh now the algorithm will +sometimes say yes even if we give it the + + align:start position:0% +sometimes say yes even if we give it the + + + align:start position:0% +sometimes say yes even if we give it the +wrong certificate uh there is no right + + align:start position:0% +wrong certificate uh there is no right + + + align:start position:0% +wrong certificate uh there is no right +certificate but it will say so with some + + align:start position:0% +certificate but it will say so with some + + + align:start position:0% +certificate but it will say so with some +uh at most constant + + align:start position:0% +uh at most constant + + + align:start position:0% +uh at most constant +probability so let's say the + + align:start position:0% +probability so let's say the + + + align:start position:0% +probability so let's say the +probability that the + + align:start position:0% +probability that the + + + align:start position:0% +probability that the +algorithm + + align:start position:0% +algorithm + + + align:start position:0% +algorithm +says + + align:start position:0% +says + + + align:start position:0% +says +no is at least some + + align:start position:0% +no is at least some + + + align:start position:0% +no is at least some +constant presumably less than one + + align:start position:0% +constant presumably less than one + + + align:start position:0% +constant presumably less than one +uh if it's one then that's + + align:start position:0% +uh if it's one then that's + + + align:start position:0% +uh if it's one then that's +NP uh if it's a half that would be fine + + align:start position:0% +NP uh if it's a half that would be fine + + + align:start position:0% +NP uh if it's a half that would be fine +a tenth a 100th though they'll all be + + align:start position:0% +a tenth a 100th though they'll all be + + + align:start position:0% +a tenth a 100th though they'll all be +the same uh because once you have such + + align:start position:0% +the same uh because once you have such + + + align:start position:0% +the same uh because once you have such +an algorithm that achieves some constant + + align:start position:0% +an algorithm that achieves some constant + + + align:start position:0% +an algorithm that achieves some constant +probability you can apply it uh log 1 + + align:start position:0% +probability you can apply it uh log 1 + + + align:start position:0% +probability you can apply it uh log 1 +over Epsilon + + align:start position:0% + + + + align:start position:0% + +times and uh we reduce the + + align:start position:0% +times and uh we reduce the + + + align:start position:0% +times and uh we reduce the +error to + + align:start position:0% + + + + align:start position:0% + +Epsilon the probability error goes to + + align:start position:0% +Epsilon the probability error goes to + + + align:start position:0% +Epsilon the probability error goes to +Epsilon if we just repeat this log 1 + + align:start position:0% +Epsilon if we just repeat this log 1 + + + align:start position:0% +Epsilon if we just repeat this log 1 +over Epsilon times so in constant + + align:start position:0% +over Epsilon times so in constant + + + align:start position:0% +over Epsilon times so in constant +time uh so it didn't say uh the order + + align:start position:0% +time uh so it didn't say uh the order + + + align:start position:0% +time uh so it didn't say uh the order +one here refers to the running time of + + align:start position:0% +one here refers to the running time of + + + align:start position:0% +one here refers to the running time of +the algorithm so this is an order one + + align:start position:0% +the algorithm so this is an order one + + + align:start position:0% +the algorithm so this is an order one +time algorithm so the point is the + + align:start position:0% +time algorithm so the point is the + + + align:start position:0% +time algorithm so the point is the +algorithm super fast and still in + + align:start position:0% +algorithm super fast and still in + + + align:start position:0% +algorithm super fast and still in +constant time for constant Epsilon you + + align:start position:0% +constant time for constant Epsilon you + + + align:start position:0% +constant time for constant Epsilon you +can get arbitrarily small error + + align:start position:0% +can get arbitrarily small error + + + align:start position:0% +can get arbitrarily small error +probability uh say one in 100 or one in + + align:start position:0% +probability uh say one in 100 or one in + + + align:start position:0% +probability uh say one in 100 or one in +a million and uh + + align:start position:0% +a million and uh + + + align:start position:0% +a million and uh +it's still pretty good and you're + + align:start position:0% +it's still pretty good and you're + + + align:start position:0% +it's still pretty good and you're +checking your proof super super fast + + align:start position:0% +checking your proof super super fast + + + align:start position:0% +checking your proof super super fast +question why is there a limit on the + + align:start position:0% +question why is there a limit on the + + + align:start position:0% +question why is there a limit on the +randomness + + align:start position:0% +randomness + + + align:start position:0% +randomness +uh this limit on Randomness is not + + align:start position:0% +uh this limit on Randomness is not + + + align:start position:0% +uh this limit on Randomness is not +strictly necessary uh for example n Bits + + align:start position:0% +strictly necessary uh for example n Bits + + + align:start position:0% +strictly necessary uh for example n Bits +of Randomness turn out not to help you + + align:start position:0% +of Randomness turn out not to help you + + + align:start position:0% +of Randomness turn out not to help you +that was proved later but uh we're going + + align:start position:0% +that was proved later but uh we're going + + + align:start position:0% +that was proved later but uh we're going +to use this in a moment it will help us + + align:start position:0% +to use this in a moment it will help us + + + align:start position:0% +to use this in a moment it will help us +uh simulate this algorithm without + + align:start position:0% +uh simulate this algorithm without + + + align:start position:0% +uh simulate this algorithm without +Randomness basically yeah the verifier + + align:start position:0% +Randomness basically yeah the verifier + + + align:start position:0% +Randomness basically yeah the verifier +runs in constant time can even read all + + align:start position:0% +runs in constant time can even read all + + + align:start position:0% +runs in constant time can even read all +his r uh so this is constant time in a + + align:start position:0% +his r uh so this is constant time in a + + + align:start position:0% +his r uh so this is constant time in a +model of computation where you can read + + align:start position:0% +model of computation where you can read + + + align:start position:0% +model of computation where you can read +log n Bits in one step so your word + + align:start position:0% +log n Bits in one step so your word + + + align:start position:0% +log n Bits in one step so your word +let's say is log n Bits long so you have + + align:start position:0% +let's say is log n Bits long so you have + + + align:start position:0% +let's say is log n Bits long so you have +enough time to read the randomness + + align:start position:0% +enough time to read the randomness + + + align:start position:0% +enough time to read the randomness +obviously you don't have time to read + + align:start position:0% +obviously you don't have time to read + + + align:start position:0% +obviously you don't have time to read +the certificate because that has + + align:start position:0% +the certificate because that has + + + align:start position:0% +the certificate because that has +polinomial length uh but yeah constant + + align:start position:0% +polinomial length uh but yeah constant + + + align:start position:0% +polinomial length uh but yeah constant +time cool other questions so that is the + + align:start position:0% +time cool other questions so that is the + + + align:start position:0% +time cool other questions so that is the +definition of PCP now let me relate it + + align:start position:0% +definition of PCP now let me relate it + + + align:start position:0% +definition of PCP now let me relate it +to Gap problems + + align:start position:0% +to Gap problems + + + align:start position:0% +to Gap problems +uh + + align:start position:0% +uh + + + align:start position:0% +uh +so let's + + align:start position:0% + + + + align:start position:0% + +say uh first claim is that if we look at + + align:start position:0% +say uh first claim is that if we look at + + + align:start position:0% +say uh first claim is that if we look at +this uh Gap sat problem where b equals 1 + + align:start position:0% +this uh Gap sat problem where b equals 1 + + + align:start position:0% +this uh Gap sat problem where b equals 1 +and a is some constant presumably less + + align:start position:0% +and a is some constant presumably less + + + align:start position:0% +and a is some constant presumably less +than one uh then in fact that should be + + align:start position:0% +than one uh then in fact that should be + + + align:start position:0% +than one uh then in fact that should be +less than one why don't I write uh + + align:start position:0% +less than one why don't I write uh + + + align:start position:0% +less than one why don't I write uh +strictly less than one here this is a + + align:start position:0% +strictly less than one here this is a + + + align:start position:0% +strictly less than one here this is a +constant less than one then uh I claim + + align:start position:0% +constant less than one then uh I claim + + + align:start position:0% +constant less than one then uh I claim +that problem is in + + align:start position:0% +that problem is in + + + align:start position:0% +that problem is in +PCP that there is a probabilistically + + align:start position:0% +PCP that there is a probabilistically + + + align:start position:0% +PCP that there is a probabilistically +checkable proof for this instance namely + + align:start position:0% +checkable proof for this instance namely + + + align:start position:0% +checkable proof for this instance namely +it's a satisfying variable assignment + + align:start position:0% +it's a satisfying variable assignment + + + align:start position:0% +it's a satisfying variable assignment +again it's this instance either has the + + align:start position:0% +again it's this instance either has the + + + align:start position:0% +again it's this instance either has the +prop when in yes instance all of the + + align:start position:0% +prop when in yes instance all of the + + + align:start position:0% +prop when in yes instance all of the +entire thing is satisfiable so just like + + align:start position:0% +entire thing is satisfiable so just like + + + align:start position:0% +entire thing is satisfiable so just like +before uh I can have a + + align:start position:0% + + + + align:start position:0% + +certificate just like an + + align:start position:0% +certificate just like an + + + align:start position:0% +certificate just like an +NP satisfying assignment to the + + align:start position:0% +NP satisfying assignment to the + + + align:start position:0% +NP satisfying assignment to the +variables is + + align:start position:0% + + + + align:start position:0% + +good in the no instance now I know let's + + align:start position:0% +good in the no instance now I know let's + + + align:start position:0% +good in the no instance now I know let's +say h most half of the things are + + align:start position:0% +say h most half of the things are + + + align:start position:0% +say h most half of the things are +satisfied if this was one + + align:start position:0% +satisfied if this was one + + + align:start position:0% +satisfied if this was one +half um and so what is my algorithm + + align:start position:0% +half um and so what is my algorithm + + + align:start position:0% +half um and so what is my algorithm +going to + + align:start position:0% +going to + + + align:start position:0% +going to +do uh in order to get some constant prob + + align:start position:0% +do uh in order to get some constant prob + + + align:start position:0% +do uh in order to get some constant prob +at most constant probability of failure + + align:start position:0% +at most constant probability of failure + + + align:start position:0% +at most constant probability of failure +it's going to choose a random clause and + + align:start position:0% +it's going to choose a random clause and + + + align:start position:0% +it's going to choose a random clause and +check that it was + + align:start position:0% + + + + align:start position:0% + +satisfied + + align:start position:0% +satisfied + + + align:start position:0% +satisfied +uh uniform random so I've got log n Bits + + align:start position:0% +uh uniform random so I've got log n Bits + + + align:start position:0% +uh uniform random so I've got log n Bits +let's say there are n clauses + + align:start position:0% +let's say there are n clauses + + + align:start position:0% +let's say there are n clauses +so I can choose one of them at random by + + align:start position:0% +so I can choose one of them at random by + + + align:start position:0% +so I can choose one of them at random by +flipping login coins and then uh check + + align:start position:0% +flipping login coins and then uh check + + + align:start position:0% +flipping login coins and then uh check +so that involves this is three SATs so + + align:start position:0% +so that involves this is three SATs so + + + align:start position:0% +so that involves this is three SATs so +it only involves three variables I check + + align:start position:0% +it only involves three variables I check + + + align:start position:0% +it only involves three variables I check +those three variable value assignments + + align:start position:0% +those three variable value assignments + + + align:start position:0% +those three variable value assignments +in my certificate just R by random + + align:start position:0% +in my certificate just R by random + + + align:start position:0% +in my certificate just R by random +access into the certificate uh in + + align:start position:0% +access into the certificate uh in + + + align:start position:0% +access into the certificate uh in +constant time I determine whether that + + align:start position:0% +constant time I determine whether that + + + align:start position:0% +constant time I determine whether that +Clause is satisfied if this Clause is + + align:start position:0% +Clause is satisfied if this Clause is + + + align:start position:0% +Clause is satisfied if this Clause is +satisfied algorithm returns yes + + align:start position:0% +satisfied algorithm returns yes + + + align:start position:0% +satisfied algorithm returns yes +otherwise return no now if it was a + + align:start position:0% +otherwise return no now if it was a + + + align:start position:0% +otherwise return no now if it was a +satisfying assignment the algorithm will + + align:start position:0% +satisfying assignment the algorithm will + + + align:start position:0% +satisfying assignment the algorithm will +always say yes so that's good uh if it + + align:start position:0% +always say yes so that's good uh if it + + + align:start position:0% +always say yes so that's good uh if it +wasn't if it was not satisfiable we know + + align:start position:0% +wasn't if it was not satisfiable we know + + + align:start position:0% +wasn't if it was not satisfiable we know +that let's say at most half of the + + align:start position:0% +that let's say at most half of the + + + align:start position:0% +that let's say at most half of the +Clauses are + + align:start position:0% +Clauses are + + + align:start position:0% +Clauses are +satisable which means in every + + align:start position:0% +satisable which means in every + + + align:start position:0% +satisable which means in every +certificate uh the algorithm will say no + + align:start position:0% +certificate uh the algorithm will say no + + + align:start position:0% +certificate uh the algorithm will say no +at least half the time and half is + + align:start position:0% +at least half the time and half is + + + align:start position:0% +at least half the time and half is +whatever that conston + + align:start position:0% +whatever that conston + + + align:start position:0% +whatever that conston +is uh so that + + align:start position:0% +is uh so that + + + align:start position:0% +is uh so that +means uh the + + align:start position:0% +means uh the + + + align:start position:0% +means uh the +probability that the algorithm is + + align:start position:0% +probability that the algorithm is + + + align:start position:0% +probability that the algorithm is +wrong is uh less than one over the gap + + align:start position:0% + + + + align:start position:0% + +whatever that ratio + + align:start position:0% +whatever that ratio + + + align:start position:0% +whatever that ratio +is + + align:start position:0% +is + + + align:start position:0% +is +cool yeah so does this group not then + + align:start position:0% +cool yeah so does this group not then + + + align:start position:0% +cool yeah so does this group not then +hold not hold done for General CNF so + + align:start position:0% +hold not hold done for General CNF so + + + align:start position:0% +hold not hold done for General CNF so +for General CNF you we will uh let me + + align:start position:0% +for General CNF you we will uh let me + + + align:start position:0% +for General CNF you we will uh let me +tell you the PCP + + align:start position:0% + + + + align:start position:0% + +theorem is that NP equals + + align:start position:0% +theorem is that NP equals + + + align:start position:0% +theorem is that NP equals +PCP this is proofed so all problems are + + align:start position:0% +PCP this is proofed so all problems are + + + align:start position:0% +PCP this is proofed so all problems are +in PCP but this is some motivation for + + align:start position:0% +in PCP but this is some motivation for + + + align:start position:0% +in PCP but this is some motivation for +where this class came from + + align:start position:0% +where this class came from + + + align:start position:0% +where this class came from +yeah okay uh I'm not going to prove this + + align:start position:0% +yeah okay uh I'm not going to prove this + + + align:start position:0% +yeah okay uh I'm not going to prove this +theorem uh the original proof is super + + align:start position:0% +theorem uh the original proof is super + + + align:start position:0% +theorem uh the original proof is super +long since then there have been + + align:start position:0% +long since then there have been + + + align:start position:0% +long since then there have been +relatively short proofs I think the + + align:start position:0% +relatively short proofs I think the + + + align:start position:0% +relatively short proofs I think the +shortest proof currently is two pages + + align:start position:0% +shortest proof currently is two pages + + + align:start position:0% +shortest proof currently is two pages +long still not going to prove it um + + align:start position:0% +long still not going to prove it um + + + align:start position:0% +long still not going to prove it um +because it's a bit aside the point uh to + + align:start position:0% +because it's a bit aside the point uh to + + + align:start position:0% +because it's a bit aside the point uh to +some + + align:start position:0% +some + + + align:start position:0% +some +extent it does use reductions and GAP + + align:start position:0% +extent it does use reductions and GAP + + + align:start position:0% +extent it does use reductions and GAP +Gap amplification but it's a technical + + align:start position:0% +Gap amplification but it's a technical + + + align:start position:0% +Gap amplification but it's a technical +to prove it let's + + align:start position:0% +to prove it let's + + + align:start position:0% +to prove it let's +say uh but I will give you some more + + align:start position:0% +say uh but I will give you some more + + + align:start position:0% +say uh but I will give you some more +motivation for why it's true true uh so + + align:start position:0% +motivation for why it's true true uh so + + + align:start position:0% +motivation for why it's true true uh so +for + + align:start position:0% +for + + + align:start position:0% +for +example + + align:start position:0% + + + + align:start position:0% + +um so here's one + + align:start position:0% +um so here's one + + + align:start position:0% +um so here's one +claim uh + + align:start position:0% +claim uh + + + align:start position:0% +claim uh +if order + + align:start position:0% +if order + + + align:start position:0% +if order +one change this + + align:start position:0% +one change this + + + align:start position:0% +one change this +notation if less than one comma 1 Gap + + align:start position:0% +notation if less than one comma 1 Gap + + + align:start position:0% +notation if less than one comma 1 Gap +three + + align:start position:0% + + + + align:start position:0% + +set is M hard + + align:start position:0% + + + + align:start position:0% + +then NP equals + + align:start position:0% +then NP equals + + + align:start position:0% +then NP equals +PCP so we know that this is true but + + align:start position:0% +PCP so we know that this is true but + + + align:start position:0% +PCP so we know that this is true but +before we know that uh here um so we + + align:start position:0% +before we know that uh here um so we + + + align:start position:0% +before we know that uh here um so we +just proved that this thing is in PCP uh + + align:start position:0% +just proved that this thing is in PCP uh + + + align:start position:0% +just proved that this thing is in PCP uh +and if + + align:start position:0% +and if + + + align:start position:0% +and if +furthermore this problem uh we're going + + align:start position:0% +furthermore this problem uh we're going + + + align:start position:0% +furthermore this problem uh we're going +to prove this is NP hard that's the + + align:start position:0% +to prove this is NP hard that's the + + + align:start position:0% +to prove this is NP hard that's the +motivation um if you believe that it's + + align:start position:0% +motivation um if you believe that it's + + + align:start position:0% +motivation um if you believe that it's +NP hard then we know all problems in NP + + align:start position:0% +NP hard then we know all problems in NP + + + align:start position:0% +NP hard then we know all problems in NP +can reduce to this thing and then that + + align:start position:0% +can reduce to this thing and then that + + + align:start position:0% +can reduce to this thing and then that +thing is in PCP so that tells us that + + align:start position:0% +thing is in PCP so that tells us that + + + align:start position:0% +thing is in PCP so that tells us that +all problems in NP you can convert them + + align:start position:0% +all problems in NP you can convert them + + + align:start position:0% +all problems in NP you can convert them +into less than one comma one Gap 3at and + + align:start position:0% +into less than one comma one Gap 3at and + + + align:start position:0% +into less than one comma one Gap 3at and +then uh get a PCP algorithm for them so + + align:start position:0% +then uh get a PCP algorithm for them so + + + align:start position:0% +then uh get a PCP algorithm for them so +that would be one way to prove the PCP + + align:start position:0% +that would be one way to prove the PCP + + + align:start position:0% +that would be one way to prove the PCP +theorem uh in fact the reverse is also + + align:start position:0% +theorem uh in fact the reverse is also + + + align:start position:0% +theorem uh in fact the reverse is also +true and this is sort of more directly + + align:start position:0% +true and this is sort of more directly + + + align:start position:0% +true and this is sort of more directly +useful to us uh + + align:start position:0% +useful to us uh + + + align:start position:0% +useful to us uh +if let's + + align:start position:0% +if let's + + + align:start position:0% +if let's +say + + align:start position:0% +say + + + align:start position:0% +say +threat is in PCP + + align:start position:0% + + + + align:start position:0% + +then the Gap version of threet is NP + + align:start position:0% +then the Gap version of threet is NP + + + align:start position:0% +then the Gap version of threet is NP +heart okay this is interesting because + + align:start position:0% +heart okay this is interesting because + + + align:start position:0% +heart okay this is interesting because +uh this is true because NP equals PCP in + + align:start position:0% +uh this is true because NP equals PCP in + + + align:start position:0% +uh this is true because NP equals PCP in +particular threat is in + + align:start position:0% +particular threat is in + + + align:start position:0% +particular threat is in +PCP uh and so we're going to be able to + + align:start position:0% +PCP uh and so we're going to be able to + + + align:start position:0% +PCP uh and so we're going to be able to +conclude by a very short argument that + + align:start position:0% +conclude by a very short argument that + + + align:start position:0% +conclude by a very short argument that +the Gap version of threet is also NP + + align:start position:0% +the Gap version of threet is also NP + + + align:start position:0% +the Gap version of threet is also NP +hard and this proves constant factor in + + align:start position:0% +hard and this proves constant factor in + + + align:start position:0% +hard and this proves constant factor in +approximability of threet we will see a + + align:start position:0% +approximability of threet we will see a + + + align:start position:0% +approximability of threet we will see a +tighter constant in a little bit but + + align:start position:0% +tighter constant in a little bit but + + + align:start position:0% +tighter constant in a little bit but +this will be our first first s + + align:start position:0% +this will be our first first s + + + align:start position:0% +this will be our first first s +bound um and this is a very general kind + + align:start position:0% +bound um and this is a very general kind + + + align:start position:0% +bound um and this is a very general kind +of algorithm it's kind of cool uh so + + align:start position:0% +of algorithm it's kind of cool uh so + + + align:start position:0% +of algorithm it's kind of cool uh so +suppose uh so PCP is easy for The Gap + + align:start position:0% +suppose uh so PCP is easy for The Gap + + + align:start position:0% +suppose uh so PCP is easy for The Gap +version of threat but Suppose there was + + align:start position:0% +version of threat but Suppose there was + + + align:start position:0% +version of threat but Suppose there was +a probabilistically checkable proof uh + + align:start position:0% +a probabilistically checkable proof uh + + + align:start position:0% +a probabilistically checkable proof uh +for just straight up threet when you're + + align:start position:0% +for just straight up threet when you're + + + align:start position:0% +for just straight up threet when you're +not given any Gap bound which is true it + + align:start position:0% +not given any Gap bound which is true it + + + align:start position:0% +not given any Gap bound which is true it +does exist um so we're going to use that + + align:start position:0% +does exist um so we're going to use that + + + align:start position:0% +does exist um so we're going to use that +algorithm and we're going to do a gap + + align:start position:0% +algorithm and we're going to do a gap + + + align:start position:0% +algorithm and we're going to do a gap +preserving reduction + + align:start position:0% +preserving reduction + + + align:start position:0% +preserving reduction +so let's + + align:start position:0% + + + + align:start position:0% + +say uh the PCP algorithm we're given + + align:start position:0% +say uh the PCP algorithm we're given + + + align:start position:0% +say uh the PCP algorithm we're given +because we're looking at PCP log n comma + + align:start position:0% +because we're looking at PCP log n comma + + + align:start position:0% +because we're looking at PCP log n comma +order one runs in constant time constant + + align:start position:0% +order one runs in constant time constant + + + align:start position:0% +order one runs in constant time constant +time algorithm can't do very much uh in + + align:start position:0% +time algorithm can't do very much uh in + + + align:start position:0% +time algorithm can't do very much uh in +particular I can write the algorithm and + + align:start position:0% +particular I can write the algorithm and + + + align:start position:0% +particular I can write the algorithm and +as a constant size + + align:start position:0% + + + + align:start position:0% + +formula okay it's really a distribution + + align:start position:0% +formula okay it's really a distribution + + + align:start position:0% +formula okay it's really a distribution +over such formulas defined by the log n + + align:start position:0% +over such formulas defined by the log n + + + align:start position:0% +over such formulas defined by the log n +random bits uh but let's say it's a + + align:start position:0% +random bits uh but let's say it's a + + + align:start position:0% +random bits uh but let's say it's a +random variable where at each for each + + align:start position:0% +random variable where at each for each + + + align:start position:0% +random variable where at each for each +possible random choice is a constant + + align:start position:0% +possible random choice is a constant + + + align:start position:0% +possible random choice is a constant +size formula uh that evaluates to true + + align:start position:0% +size formula uh that evaluates to true + + + align:start position:0% +size formula uh that evaluates to true +or false corresponding to whether the + + align:start position:0% +or false corresponding to whether the + + + align:start position:0% +or false corresponding to whether the +algorithm says yes or no we know we can + + align:start position:0% +algorithm says yes or no we know we can + + + align:start position:0% +algorithm says yes or no we know we can +convert algorithms to formulas if + + align:start position:0% +convert algorithms to formulas if + + + align:start position:0% +convert algorithms to formulas if +they're if they're short amount of + + align:start position:0% +they're if they're short amount of + + + align:start position:0% +they're if they're short amount of +time uh so we can make had a CNF formula + + align:start position:0% +time uh so we can make had a CNF formula + + + align:start position:0% +time uh so we can make had a CNF formula +why + + align:start position:0% +why + + + align:start position:0% +why +not 3 CNF if we want my goal is to uh I + + align:start position:0% +not 3 CNF if we want my goal is to uh I + + + align:start position:0% +not 3 CNF if we want my goal is to uh I +want to reduce threat to the Gap version + + align:start position:0% +want to reduce threat to the Gap version + + + align:start position:0% +want to reduce threat to the Gap version +of threat because threat we know is EMP + + align:start position:0% +of threat because threat we know is EMP + + + align:start position:0% +of threat because threat we know is EMP +hard so if I can reduce it to the Gap + + align:start position:0% +hard so if I can reduce it to the Gap + + + align:start position:0% +hard so if I can reduce it to the Gap +version of threat I'm happy then I know + + align:start position:0% +version of threat I'm happy then I know + + + align:start position:0% +version of threat I'm happy then I know +the Gap version of threet is also hard + + align:start position:0% +the Gap version of threet is also hard + + + align:start position:0% +the Gap version of threet is also hard +so here is my + + align:start position:0% +so here is my + + + align:start position:0% +so here is my +reduction uh I'm going to so I'm given + + align:start position:0% +reduction uh I'm going to so I'm given + + + align:start position:0% +reduction uh I'm going to so I'm given +the threat formula uh and the algorithm + + align:start position:0% +the threat formula uh and the algorithm + + + align:start position:0% +the threat formula uh and the algorithm +evaluates some form formula on it and + + align:start position:0% +evaluates some form formula on it and + + + align:start position:0% +evaluates some form formula on it and +the + + align:start position:0% +the + + + align:start position:0% +the +certificate uh what I'm going to + + align:start position:0% +certificate uh what I'm going to + + + align:start position:0% +certificate uh what I'm going to +do + + align:start position:0% + + + + align:start position:0% + +is uh try all of the random + + align:start position:0% +is uh try all of the random + + + align:start position:0% +is uh try all of the random +choices because there's only log n Bits + + align:start position:0% +choices because there's only log n Bits + + + align:start position:0% +choices because there's only log n Bits +there's only polom many possible choices + + align:start position:0% +there's only polom many possible choices + + + align:start position:0% +there's only polom many possible choices +for those + + align:start position:0% + + + + align:start position:0% + +bits it's order log n as n to some + + align:start position:0% +bits it's order log n as n to some + + + align:start position:0% +bits it's order log n as n to some +constant and I want to take this formula + + align:start position:0% +constant and I want to take this formula + + + align:start position:0% +constant and I want to take this formula +take the conjunction over all of those + + align:start position:0% +take the conjunction over all of those + + + align:start position:0% +take the conjunction over all of those +choices if if the Alm always says + + align:start position:0% +choices if if the Alm always says + + + align:start position:0% +choices if if the Alm always says +yes uh then this formula will be + + align:start position:0% +yes uh then this formula will be + + + align:start position:0% +yes uh then this formula will be +satisfiable so in the yes instance case + + align:start position:0% +satisfiable so in the yes instance case + + + align:start position:0% +satisfiable so in the yes instance case +I get a satisfiable + + align:start position:0% +I get a satisfiable + + + align:start position:0% +I get a satisfiable +formula so + + align:start position:0% +formula so + + + align:start position:0% +formula so +yes + + align:start position:0% +yes + + + align:start position:0% +yes +implies satisfiable 100% + + align:start position:0% +implies satisfiable 100% + + + align:start position:0% +implies satisfiable 100% +satisfiable that corresponds to this + + align:start position:0% +satisfiable that corresponds to this + + + align:start position:0% +satisfiable that corresponds to this +number I want it to be 100% in the yes + + align:start position:0% +number I want it to be 100% in the yes + + + align:start position:0% +number I want it to be 100% in the yes +case um in the no + + align:start position:0% + + + + align:start position:0% + +case uh I know that uh a constant + + align:start position:0% +case uh I know that uh a constant + + + align:start position:0% +case uh I know that uh a constant +fraction of these random choices give a + + align:start position:0% +fraction of these random choices give a + + + align:start position:0% +fraction of these random choices give a +no meaning uh they will not be satisfied + + align:start position:0% +no meaning uh they will not be satisfied + + + align:start position:0% +no meaning uh they will not be satisfied +for any choice any uh certificate I know + + align:start position:0% +for any choice any uh certificate I know + + + align:start position:0% +for any choice any uh certificate I know +that a constant fraction of these terms + + align:start position:0% +that a constant fraction of these terms + + + align:start position:0% +that a constant fraction of these terms +which I'm conjuncting will evaluate to + + align:start position:0% +which I'm conjuncting will evaluate to + + + align:start position:0% +which I'm conjuncting will evaluate to +false because of the definition of PCP + + align:start position:0% +false because of the definition of PCP + + + align:start position:0% +false because of the definition of PCP +that's what probability algorithm saying + + align:start position:0% +that's what probability algorithm saying + + + align:start position:0% +that's what probability algorithm saying +no + + align:start position:0% +no + + + align:start position:0% +no +means um + + align:start position:0% +means um + + + align:start position:0% +means um +so uh let's say + + align:start position:0% +so uh let's say + + + align:start position:0% +so uh let's say +constant + + align:start position:0% + + + + align:start position:0% + +fraction of the + + align:start position:0% +fraction of the + + + align:start position:0% +fraction of the +terms are + + align:start position:0% +terms are + + + align:start position:0% +terms are +false the terms are the things we're + + align:start position:0% +false the terms are the things we're + + + align:start position:0% +false the terms are the things we're +conjuncting over uh but each each term + + align:start position:0% +conjuncting over uh but each each term + + + align:start position:0% +conjuncting over uh but each each term +here is a constant size CNF + + align:start position:0% +here is a constant size CNF + + + align:start position:0% +here is a constant size CNF +formula so when I and those together I + + align:start position:0% +formula so when I and those together I + + + align:start position:0% +formula so when I and those together I +really just get one giant and of + + align:start position:0% +really just get one giant and of + + + align:start position:0% +really just get one giant and of +Clauses constant fraction larger than + + align:start position:0% +Clauses constant fraction larger than + + + align:start position:0% +Clauses constant fraction larger than +the number of terms and if a term is + + align:start position:0% +the number of terms and if a term is + + + align:start position:0% +the number of terms and if a term is +false + + align:start position:0% +false + + + align:start position:0% +false +that means at least one of the Clauses + + align:start position:0% +that means at least one of the Clauses + + + align:start position:0% +that means at least one of the Clauses +is false and there's only a constant + + align:start position:0% +is false and there's only a constant + + + align:start position:0% +is false and there's only a constant +number of Clauses in each term so this + + align:start position:0% +number of Clauses in each term so this + + + align:start position:0% +number of Clauses in each term so this +means a constant fraction of the Clauses + + align:start position:0% +means a constant fraction of the Clauses + + + align:start position:0% +means a constant fraction of the Clauses +in that giant con conjunction are also + + align:start position:0% + + + + align:start position:0% + +false and that is essentially + + align:start position:0% +false and that is essentially + + + align:start position:0% +false and that is essentially +it let me + + align:start position:0% + + + + align:start position:0% + +that is my + + align:start position:0% + + + + align:start position:0% + +reduction uh so in the yes instance I + + align:start position:0% +reduction uh so in the yes instance I + + + align:start position:0% +reduction uh so in the yes instance I +get 100% satisfiable thing in the no + + align:start position:0% +get 100% satisfiable thing in the no + + + align:start position:0% +get 100% satisfiable thing in the no +instance I get some constant strictly + + align:start position:0% +instance I get some constant strictly + + + align:start position:0% +instance I get some constant strictly +less than one satisfiable thing because + + align:start position:0% +less than one satisfiable thing because + + + align:start position:0% +less than one satisfiable thing because +in any solution I get a constant + + align:start position:0% +in any solution I get a constant + + + align:start position:0% +in any solution I get a constant +fraction that turn out to be false + + align:start position:0% +fraction that turn out to be false + + + align:start position:0% +fraction that turn out to be false +constant fraction of the Clauses now + + align:start position:0% +constant fraction of the Clauses now + + + align:start position:0% +constant fraction of the Clauses now +what the constant is you'd have to work + + align:start position:0% +what the constant is you'd have to work + + + align:start position:0% +what the constant is you'd have to work +out things you'd have to know how big + + align:start position:0% +out things you'd have to know how big + + + align:start position:0% +out things you'd have to know how big +your PCP algorithm is but at least we + + align:start position:0% +your PCP algorithm is but at least we + + + align:start position:0% +your PCP algorithm is but at least we +get a constant lower bound proving uh in + + align:start position:0% +get a constant lower bound proving uh in + + + align:start position:0% +get a constant lower bound proving uh in +particular proving there's no P task for + + align:start position:0% +particular proving there's no P task for + + + align:start position:0% +particular proving there's no P task for +Max 3 set this is what you might call a + + align:start position:0% +Max 3 set this is what you might call a + + + align:start position:0% +Max 3 set this is what you might call a +gap amplifying reduction in the sense we + + align:start position:0% +gap amplifying reduction in the sense we + + + align:start position:0% +gap amplifying reduction in the sense we +started with no Gap the the instance of + + align:start position:0% +started with no Gap the the instance of + + + align:start position:0% +started with no Gap the the instance of +three set was either true or false and + + align:start position:0% +three set was either true or false and + + + align:start position:0% +three set was either true or false and +we ended up with something with a + + align:start position:0% +we ended up with something with a + + + align:start position:0% +we ended up with something with a +significant Gap + + align:start position:0% +significant Gap + + + align:start position:0% +significant Gap +um fine uh so what we're going to talk + + align:start position:0% +um fine uh so what we're going to talk + + + align:start position:0% +um fine uh so what we're going to talk +about next is called Gap preserving R + + align:start position:0% + + + + align:start position:0% + +reductions but maybe before I get there + + align:start position:0% +reductions but maybe before I get there + + + align:start position:0% +reductions but maybe before I get there +um what we just showed is that uh the + + align:start position:0% +um what we just showed is that uh the + + + align:start position:0% +um what we just showed is that uh the +PCP theorem is equivalent and in + + align:start position:0% +PCP theorem is equivalent and in + + + align:start position:0% +PCP theorem is equivalent and in +particular we get uh Gap problems being + + align:start position:0% +particular we get uh Gap problems being + + + align:start position:0% +particular we get uh Gap problems being +NP this is why we care about + + align:start position:0% +NP this is why we care about + + + align:start position:0% +NP this is why we care about +pcps um and uh then in general once we + + align:start position:0% +pcps um and uh then in general once we + + + align:start position:0% +pcps um and uh then in general once we +have these kinds of Gap hardness results + + align:start position:0% +have these kinds of Gap hardness results + + + align:start position:0% +have these kinds of Gap hardness results +we convert our when we're thinking about + + align:start position:0% +we convert our when we're thinking about + + + align:start position:0% +we convert our when we're thinking about +reductions from A to B you I mean + + align:start position:0% +reductions from A to B you I mean + + + align:start position:0% +reductions from A to B you I mean +because we know Gap implies + + align:start position:0% +because we know Gap implies + + + align:start position:0% +because we know Gap implies +inapproximability we could say Okay + + align:start position:0% +inapproximability we could say Okay + + + align:start position:0% +inapproximability we could say Okay +threat is in approximable and then do + + align:start position:0% +threat is in approximable and then do + + + align:start position:0% +threat is in approximable and then do +say an L reduction from threat to + + align:start position:0% +say an L reduction from threat to + + + align:start position:0% +say an L reduction from threat to +something else uh the something else is + + align:start position:0% +something else uh the something else is + + + align:start position:0% +something else uh the something else is +therefore inapproximability + + align:start position:0% + + + + align:start position:0% + +and how much carries from A to B we can + + align:start position:0% +and how much carries from A to B we can + + + align:start position:0% +and how much carries from A to B we can +think about the Gap directly and this is + + align:start position:0% +think about the Gap directly and this is + + + align:start position:0% +think about the Gap directly and this is +sort of the main approach in this + + align:start position:0% +sort of the main approach in this + + + align:start position:0% +sort of the main approach in this +lecture that I'm trying to demonstrate + + align:start position:0% +lecture that I'm trying to demonstrate + + + align:start position:0% +lecture that I'm trying to demonstrate +is by preserving the Gap directly a well + + align:start position:0% +is by preserving the Gap directly a well + + + align:start position:0% +is by preserving the Gap directly a well +you get new Gap bounds and generally + + align:start position:0% +you get new Gap bounds and generally + + + align:start position:0% +you get new Gap bounds and generally +stronger Gap bounds and then those imply + + align:start position:0% +stronger Gap bounds and then those imply + + + align:start position:0% +stronger Gap bounds and then those imply +in approximability results uh but the + + align:start position:0% +in approximability results uh but the + + + align:start position:0% +in approximability results uh but the +Gap bounds are stronger than the + + align:start position:0% +Gap bounds are stronger than the + + + align:start position:0% +Gap bounds are stronger than the +inapproximability and also they tend to + + align:start position:0% +inapproximability and also they tend to + + + align:start position:0% +inapproximability and also they tend to +give larger constant factors in the uh + + align:start position:0% +give larger constant factors in the uh + + + align:start position:0% +give larger constant factors in the uh +in approximability results so what do we + + align:start position:0% +in approximability results so what do we + + + align:start position:0% +in approximability results so what do we +want out of a gap preserving reduction + + align:start position:0% +want out of a gap preserving reduction + + + align:start position:0% +want out of a gap preserving reduction +let's say + + align:start position:0% +let's say + + + align:start position:0% +let's say +um we have an + + align:start position:0% +um we have an + + + align:start position:0% +um we have an +instance X of a a we convert that into + + align:start position:0% +instance X of a a we convert that into + + + align:start position:0% +instance X of a a we convert that into +an + + align:start position:0% +an + + + align:start position:0% +an +instance X + + align:start position:0% +instance X + + + align:start position:0% +instance X +Prime of some problem + + align:start position:0% +Prime of some problem + + + align:start position:0% +Prime of some problem +B uh we're just going to think about the + + align:start position:0% +B uh we're just going to think about the + + + align:start position:0% +B uh we're just going to think about the +opt of X versus the opt of X + + align:start position:0% +opt of X versus the opt of X + + + align:start position:0% +opt of X versus the opt of X +Prime and what we + + align:start position:0% +Prime and what we + + + align:start position:0% +Prime and what we +want uh for let's say a minimization + + align:start position:0% +want uh for let's say a minimization + + + align:start position:0% +want uh for let's say a minimization +problem is two + + align:start position:0% +problem is two + + + align:start position:0% +problem is two +properties one is that the + + align:start position:0% +properties one is that the + + + align:start position:0% +properties one is that the +opt if the opt of X is at most sum k + + align:start position:0% +opt if the opt of X is at most sum k + + + align:start position:0% +opt if the opt of X is at most sum k +then the opt of X + + align:start position:0% + + + + align:start position:0% + +Prime is at most sum K + + align:start position:0% +Prime is at most sum K + + + align:start position:0% +Prime is at most sum K +Prime + + align:start position:0% +Prime + + + align:start position:0% +Prime +and + + align:start position:0% + + + + align:start position:0% + +conversely okay so in general opt may + + align:start position:0% +conversely okay so in general opt may + + + align:start position:0% +conversely okay so in general opt may +not be preserved but let's say uh + + align:start position:0% +not be preserved but let's say uh + + + align:start position:0% +not be preserved but let's say uh +it changes by some prime operation so in + + align:start position:0% +it changes by some prime operation so in + + + align:start position:0% +it changes by some prime operation so in +fact you can think of K and K Prime as + + align:start position:0% +fact you can think of K and K Prime as + + + align:start position:0% +fact you can think of K and K Prime as +uh functions of + + align:start position:0% +uh functions of + + + align:start position:0% +uh functions of +n okay so if I know that opt of X is at + + align:start position:0% +n okay so if I know that opt of X is at + + + align:start position:0% +n okay so if I know that opt of X is at +most some function of n then I get that + + align:start position:0% +most some function of n then I get that + + + align:start position:0% +most some function of n then I get that +opt uh of X Prime is at most some other + + align:start position:0% +opt uh of X Prime is at most some other + + + align:start position:0% +opt uh of X Prime is at most some other +function of n but there's some known + + align:start position:0% +function of n but there's some known + + + align:start position:0% +function of n but there's some known +relation between the two what I care + + align:start position:0% +relation between the two what I care + + + align:start position:0% +relation between the two what I care +about is this Gap C uh should be a c + + align:start position:0% +about is this Gap C uh should be a c + + + align:start position:0% +about is this Gap C uh should be a c +Prime here so this is what this is + + align:start position:0% +Prime here so this is what this is + + + align:start position:0% +Prime here so this is what this is +saying is suppose I had a gap if I know + + align:start position:0% +saying is suppose I had a gap if I know + + + align:start position:0% +saying is suppose I had a gap if I know +that all Solutions are either less than + + align:start position:0% +that all Solutions are either less than + + + align:start position:0% +that all Solutions are either less than +K or more than C * K I want that to be + + align:start position:0% +K or more than C * K I want that to be + + + align:start position:0% +K or more than C * K I want that to be +preserved for some possibly other gap C + + align:start position:0% +preserved for some possibly other gap C + + + align:start position:0% +preserved for some possibly other gap C +Prime in the new problem okay so this is + + align:start position:0% +Prime in the new problem okay so this is + + + align:start position:0% +Prime in the new problem okay so this is +pretty General but this is the sort of + + align:start position:0% +pretty General but this is the sort of + + + align:start position:0% +pretty General but this is the sort of +thing we want to preserve if we had a + + align:start position:0% +thing we want to preserve if we had a + + + align:start position:0% +thing we want to preserve if we had a +gap of C before we get some Gap C Prime + + align:start position:0% +gap of C before we get some Gap C Prime + + + align:start position:0% +gap of C before we get some Gap C Prime +after if C Prime equals c this would be + + align:start position:0% +after if C Prime equals c this would be + + + align:start position:0% +after if C Prime equals c this would be +a perfectly Gap preserving reduction + + align:start position:0% +a perfectly Gap preserving reduction + + + align:start position:0% +a perfectly Gap preserving reduction +maybe we'll lose some constant Factor uh + + align:start position:0% +maybe we'll lose some constant Factor uh + + + align:start position:0% +maybe we'll lose some constant Factor uh +if C Prime is greater than C uh this is + + align:start position:0% +if C Prime is greater than C uh this is + + + align:start position:0% +if C Prime is greater than C uh this is +called Gap Gap amplification + + align:start position:0% + + + + align:start position:0% + +and GAP Gap amplification is essentially + + align:start position:0% +and GAP Gap amplification is essentially + + + align:start position:0% +and GAP Gap amplification is essentially +how the PCP theorem is shown uh + + align:start position:0% +how the PCP theorem is shown uh + + + align:start position:0% +how the PCP theorem is shown uh +by repeatedly growing the Gap until it's + + align:start position:0% +by repeatedly growing the Gap until it's + + + align:start position:0% +by repeatedly growing the Gap until it's +something reasonable um and if you want + + align:start position:0% +something reasonable um and if you want + + + align:start position:0% +something reasonable um and if you want +to say prove that set cover is log n + + align:start position:0% +to say prove that set cover is log n + + + align:start position:0% +to say prove that set cover is log n +hard it's a similar thing where you + + align:start position:0% +hard it's a similar thing where you + + + align:start position:0% +hard it's a similar thing where you +start with a small Gap constant factor + + align:start position:0% +start with a small Gap constant factor + + + align:start position:0% +start with a small Gap constant factor +and then you grow it and you show you + + align:start position:0% +and then you grow it and you show you + + + align:start position:0% +and then you grow it and you show you +can grow it to log n before you run out + + align:start position:0% +can grow it to log n before you run out + + + align:start position:0% +can grow it to log n before you run out +of space to write it in your problem + + align:start position:0% +of space to write it in your problem + + + align:start position:0% +of space to write it in your problem +essentially before your instance gets + + align:start position:0% +essentially before your instance gets + + + align:start position:0% +essentially before your instance gets +more than polinomial uh or if you want + + align:start position:0% +more than polinomial uh or if you want + + + align:start position:0% +more than polinomial uh or if you want +to prove that click can't be solved in + + align:start position:0% +to prove that click can't be solved in + + + align:start position:0% +to prove that click can't be solved in +better than uh whatever n to the one + + align:start position:0% +better than uh whatever n to the one + + + align:start position:0% +better than uh whatever n to the one +minus Epsilon then a similar trick of + + align:start position:0% +minus Epsilon then a similar trick of + + + align:start position:0% +minus Epsilon then a similar trick of +Gap amplification Works those + + align:start position:0% +Gap amplification Works those + + + align:start position:0% +Gap amplification Works those +amplification arguments are involved and + + align:start position:0% +amplification arguments are involved and + + + align:start position:0% +amplification arguments are involved and +so I'm not going to show them here um + + align:start position:0% +so I'm not going to show them here um + + + align:start position:0% +so I'm not going to show them here um +but I will show you an example of a gap + + align:start position:0% +but I will show you an example of a gap + + + align:start position:0% +but I will show you an example of a gap +preserving reduction next unless there + + align:start position:0% +preserving reduction next unless there + + + align:start position:0% +preserving reduction next unless there +are + + align:start position:0% + + + + align:start position:0% + +questions cool so + + align:start position:0% + + + + align:start position:0% + +I'm going to + + align:start position:0% +I'm going to + + + align:start position:0% +I'm going to +reduce uh a problem which we have + + align:start position:0% +reduce uh a problem which we have + + + align:start position:0% +reduce uh a problem which we have +mentioned + + align:start position:0% + + + + align:start position:0% + +before this um which is Max exactly + + align:start position:0% +before this um which is Max exactly + + + align:start position:0% +before this um which is Max exactly +three xor and X nor set this is uh + + align:start position:0% +three xor and X nor set this is uh + + + align:start position:0% +three xor and X nor set this is uh +linear equations mod 2 where every term + + align:start position:0% +linear equations mod 2 where every term + + + align:start position:0% +linear equations mod 2 where every term +has exactly sorry every equation has + + align:start position:0% +has exactly sorry every equation has + + + align:start position:0% +has exactly sorry every equation has +exactly three terms right so something + + align:start position:0% +exactly three terms right so something + + + align:start position:0% +exactly three terms right so something +like uh x i x or + + align:start position:0% +like uh x i x or + + + align:start position:0% +like uh x i x or +XJ X or XK equals one or something uh + + align:start position:0% +XJ X or XK equals one or something uh + + + align:start position:0% +XJ X or XK equals one or something uh +you can also have negations + + align:start position:0% +you can also have negations + + + align:start position:0% +you can also have negations +here okay so I have a bunch of equations + + align:start position:0% +here okay so I have a bunch of equations + + + align:start position:0% +here okay so I have a bunch of equations +like that uh I'm going to just tell you + + align:start position:0% +like that uh I'm going to just tell you + + + align:start position:0% +like that uh I'm going to just tell you +a gap bound on this problem and then + + align:start position:0% +a gap bound on this problem and then + + + align:start position:0% +a gap bound on this problem and then +we're going to reduce it to another + + align:start position:0% +we're going to reduce it to another + + + align:start position:0% +we're going to reduce it to another +problem namely Max E3 + + align:start position:0% +problem namely Max E3 + + + align:start position:0% +problem namely Max E3 +set so uh the claim here is this problem + + align:start position:0% +set so uh the claim here is this problem + + + align:start position:0% +set so uh the claim here is this problem +is 12 + Epsilon 1 - + + align:start position:0% +is 12 + Epsilon 1 - + + + align:start position:0% +is 12 + Epsilon 1 - +Epsilon Gap + + align:start position:0% + + + + align:start position:0% + +hard for any + + align:start position:0% + + + + align:start position:0% + +Epsilon uh which in particular implies + + align:start position:0% +Epsilon uh which in particular implies + + + align:start position:0% +Epsilon uh which in particular implies +that it is uh 12 minus Epsilon in + + align:start position:0% +that it is uh 12 minus Epsilon in + + + align:start position:0% +that it is uh 12 minus Epsilon in +approximable unless P equal + + align:start position:0% + + + + align:start position:0% + +NP uh but this is of course stronger it + + align:start position:0% +NP uh but this is of course stronger it + + + align:start position:0% +NP uh but this is of course stronger it +says uh if you just look at instances + + align:start position:0% +says uh if you just look at instances + + + align:start position:0% +says uh if you just look at instances +where uh say 99% of the uh for of the + + align:start position:0% +where uh say 99% of the uh for of the + + + align:start position:0% +where uh say 99% of the uh for of the +equations are satisfiable + + align:start position:0% +equations are satisfiable + + + align:start position:0% +equations are satisfiable +versus uh when 51% are satisfiable it's + + align:start position:0% +versus uh when 51% are satisfiable it's + + + align:start position:0% +versus uh when 51% are satisfiable it's +empty hard to distinguish between those + + align:start position:0% +empty hard to distinguish between those + + + align:start position:0% +empty hard to distinguish between those +two um why 1/2 here because there is a + + align:start position:0% +two um why 1/2 here because there is a + + + align:start position:0% +two um why 1/2 here because there is a +1/ half + + align:start position:0% + + + + align:start position:0% + +approximation I've kind of mentioned the + + align:start position:0% +approximation I've kind of mentioned the + + + align:start position:0% +approximation I've kind of mentioned the +general approach for oximation algorithm + + align:start position:0% +general approach for oximation algorithm + + + align:start position:0% +general approach for oximation algorithm +for sat is take a random assignment + + align:start position:0% +for sat is take a random assignment + + + align:start position:0% +for sat is take a random assignment +variable assignment um and in this case + + align:start position:0% +variable assignment um and in this case + + + align:start position:0% +variable assignment um and in this case +because these statements are about a + + align:start position:0% +because these statements are about a + + + align:start position:0% +because these statements are about a +par uh you if you think of XK as random + + align:start position:0% +par uh you if you think of XK as random + + + align:start position:0% +par uh you if you think of XK as random +it doesn't matter what these two are 50% + + align:start position:0% +it doesn't matter what these two are 50% + + + align:start position:0% +it doesn't matter what these two are 50% +probability this will be satisfied and + + align:start position:0% +probability this will be satisfied and + + + align:start position:0% +probability this will be satisfied and +so you can always satisfy at least half + + align:start position:0% +so you can always satisfy at least half + + + align:start position:0% +so you can always satisfy at least half +of the Clauses because a Rand this + + align:start position:0% +of the Clauses because a Rand this + + + align:start position:0% +of the Clauses because a Rand this +randomized algorithm will satisfy half + + align:start position:0% +randomized algorithm will satisfy half + + + align:start position:0% +randomized algorithm will satisfy half +in expectation therefore at least one + + align:start position:0% +in expectation therefore at least one + + + align:start position:0% +in expectation therefore at least one +instance it will do so uh but if you + + align:start position:0% +instance it will do so uh but if you + + + align:start position:0% +instance it will do so uh but if you +allow randomized approximation this is a + + align:start position:0% +allow randomized approximation this is a + + + align:start position:0% +allow randomized approximation this is a +one half approximation or a two + + align:start position:0% +one half approximation or a two + + + align:start position:0% +one half approximation or a two +approximation depending on your + + align:start position:0% +approximation depending on your + + + align:start position:0% +approximation depending on your +perspective uh so this is really tight + + align:start position:0% +perspective uh so this is really tight + + + align:start position:0% +perspective uh so this is really tight +that's good news and this is this is + + align:start position:0% +that's good news and this is this is + + + align:start position:0% +that's good news and this is this is +proved this is essentially a form of the + + align:start position:0% +proved this is essentially a form of the + + + align:start position:0% +proved this is essentially a form of the +PCP theorem um PCP theorem says that uh + + align:start position:0% +PCP theorem um PCP theorem says that uh + + + align:start position:0% +PCP theorem um PCP theorem says that uh +you can there's some + + align:start position:0% +you can there's some + + + align:start position:0% +you can there's some +algorithm and you can prove that in fact + + align:start position:0% +algorithm and you can prove that in fact + + + align:start position:0% +algorithm and you can prove that in fact +there is an algorithm that looks like + + align:start position:0% +there is an algorithm that looks like + + + align:start position:0% +there is an algorithm that looks like +this it's a bunch of uh linear equations + + align:start position:0% +this it's a bunch of uh linear equations + + + align:start position:0% +this it's a bunch of uh linear equations +with three terms per uh equation + + align:start position:0% +with three terms per uh equation + + + align:start position:0% +with three terms per uh equation +okay + + align:start position:0% + + + + align:start position:0% + +so let's take that as + + align:start position:0% + + + + align:start position:0% + +given now what I want to show is a + + align:start position:0% +given now what I want to show is a + + + align:start position:0% +given now what I want to show is a +reduction from that problem to Max E3 + + align:start position:0% +reduction from that problem to Max E3 + + + align:start position:0% +reduction from that problem to Max E3 +set so remember Max E3 + + align:start position:0% + + + + align:start position:0% + +Set uh you're given CNF where every + + align:start position:0% +Set uh you're given CNF where every + + + align:start position:0% +Set uh you're given CNF where every +Clause has exact three distinct literals + + align:start position:0% +Clause has exact three distinct literals + + + align:start position:0% +Clause has exact three distinct literals +uh you want to maximize the number of + + align:start position:0% +uh you want to maximize the number of + + + align:start position:0% +uh you want to maximize the number of +satisfied things um so this is roughly + + align:start position:0% +satisfied things um so this is roughly + + + align:start position:0% +satisfied things um so this is roughly +the problem we were talking about up + + align:start position:0% +the problem we were talking about up + + + align:start position:0% +the problem we were talking about up +there + + align:start position:0% +there + + + align:start position:0% +there +um so first thing I'm going to do is + + align:start position:0% +um so first thing I'm going to do is + + + align:start position:0% +um so first thing I'm going to do is +uh + + align:start position:0% +uh + + + align:start position:0% +uh +oh so I I want to reduce this to + + align:start position:0% +oh so I I want to reduce this to + + + align:start position:0% +oh so I I want to reduce this to +that um and this is the reduction and + + align:start position:0% +that um and this is the reduction and + + + align:start position:0% +that um and this is the reduction and +first claim is just that it's an + + align:start position:0% +first claim is just that it's an + + + align:start position:0% +first claim is just that it's an +reduction so that's something we're + + align:start position:0% +reduction so that's something we're + + + align:start position:0% +reduction so that's something we're +familiar with let's think about it that + + align:start position:0% +familiar with let's think about it that + + + align:start position:0% +familiar with let's think about it that +way then we will think about it in a gap + + align:start position:0% +way then we will think about it in a gap + + + align:start position:0% +way then we will think about it in a gap +preserving sense okay so there are two + + align:start position:0% +preserving sense okay so there are two + + + align:start position:0% +preserving sense okay so there are two +types of equations we need to satisfy + + align:start position:0% +types of equations we need to satisfy + + + align:start position:0% +types of equations we need to satisfy +the sort of odd case or the even + + align:start position:0% +the sort of odd case or the even + + + align:start position:0% +the sort of odd case or the even +case um again each of these could be + + align:start position:0% +case um again each of these could be + + + align:start position:0% +case um again each of these could be +negated and I'm just going to double + + align:start position:0% +negated and I'm just going to double + + + align:start position:0% +negated and I'm just going to double +negate means un negated over here so uh + + align:start position:0% +negate means un negated over here so uh + + + align:start position:0% +negate means un negated over here so uh +each equation is going to be replaced + + align:start position:0% +each equation is going to be replaced + + + align:start position:0% +each equation is going to be replaced +with exactly four Clauses in the E3 set + + align:start position:0% +with exactly four Clauses in the E3 set + + + align:start position:0% +with exactly four Clauses in the E3 set +instance um and the idea is as well if I + + align:start position:0% +instance um and the idea is as well if I + + + align:start position:0% +instance um and the idea is as well if I +want them all uh the par of them to be + + align:start position:0% +want them all uh the par of them to be + + + align:start position:0% +want them all uh the par of them to be +odd uh it should be the case that at + + align:start position:0% +odd uh it should be the case that at + + + align:start position:0% +odd uh it should be the case that at +least one of them is true and if you + + align:start position:0% +least one of them is true and if you + + + align:start position:0% +least one of them is true and if you +stare at it long enough also uh when you + + align:start position:0% +stare at it long enough also uh when you + + + align:start position:0% +stare at it long enough also uh when you +put two bars in there I don't want + + align:start position:0% +put two bars in there I don't want + + + align:start position:0% +put two bars in there I don't want +exactly two of them to be true that's + + align:start position:0% +exactly two of them to be true that's + + + align:start position:0% +exactly two of them to be true that's +the parody constraint if this is true uh + + align:start position:0% +the parody constraint if this is true uh + + + align:start position:0% +the parody constraint if this is true uh +all four of these should be true that's + + align:start position:0% +all four of these should be true that's + + + align:start position:0% +all four of these should be true that's +the first claim this by the par of the + + align:start position:0% +the first claim this by the par of the + + + align:start position:0% +the first claim this by the par of the +number of bars on there's either Zero + + align:start position:0% +number of bars on there's either Zero + + + align:start position:0% +number of bars on there's either Zero +Bar or two bars or three positive or uh + + align:start position:0% +Bar or two bars or three positive or uh + + + align:start position:0% +Bar or two bars or three positive or uh +one positive those the two cases and uh + + align:start position:0% +one positive those the two cases and uh + + + align:start position:0% +one positive those the two cases and uh +in this + + align:start position:0% +in this + + + align:start position:0% +in this +situation uh where I want the parity to + + align:start position:0% +situation uh where I want the parity to + + + align:start position:0% +situation uh where I want the parity to +be even even number of truths I have all + + align:start position:0% +be even even number of truths I have all + + + align:start position:0% +be even even number of truths I have all +the even number of truths cases over + + align:start position:0% +the even number of truths cases over + + + align:start position:0% +the even number of truths cases over +here uh here are two of them even and + + align:start position:0% +here uh here are two of them even and + + + align:start position:0% +here uh here are two of them even and +here are none of them + + align:start position:0% +here are none of them + + + align:start position:0% +here are none of them +even okay and again if this is satisfied + + align:start position:0% +even okay and again if this is satisfied + + + align:start position:0% +even okay and again if this is satisfied +then all four of those are satisfied + + align:start position:0% +then all four of those are satisfied + + + align:start position:0% +then all four of those are satisfied +now if these are not + + align:start position:0% +now if these are not + + + align:start position:0% +now if these are not +satisfied uh by the same argument you + + align:start position:0% +satisfied uh by the same argument you + + + align:start position:0% +satisfied uh by the same argument you +can show that at least one of these is + + align:start position:0% +can show that at least one of these is + + + align:start position:0% +can show that at least one of these is +violated but in fact just one will be + + align:start position:0% +violated but in fact just one will be + + + align:start position:0% +violated but in fact just one will be +violated okay so for example um if so + + align:start position:0% +violated okay so for example um if so + + + align:start position:0% +violated okay so for example um if so +this is just a case analysis let's say I + + align:start position:0% +this is just a case analysis let's say I + + + align:start position:0% +this is just a case analysis let's say I +set all of these to be zero and so their + + align:start position:0% +set all of these to be zero and so their + + + align:start position:0% +set all of these to be zero and so their +xor is zero not one so if they're all + + align:start position:0% +xor is zero not one so if they're all + + + align:start position:0% +xor is zero not one so if they're all +false then this will not be satisfied + + align:start position:0% +false then this will not be satisfied + + + align:start position:0% +false then this will not be satisfied +but the other three will + + align:start position:0% +but the other three will + + + align:start position:0% +but the other three will +be um and in general + + align:start position:0% +be um and in general + + + align:start position:0% +be um and in general +because we have for example XI appearing + + align:start position:0% +because we have for example XI appearing + + + align:start position:0% +because we have for example XI appearing +true and false in different cases uh you + + align:start position:0% +true and false in different cases uh you + + + align:start position:0% +true and false in different cases uh you +will satisfy three out of four in when + + align:start position:0% +will satisfy three out of four in when + + + align:start position:0% +will satisfy three out of four in when +on the right when you don't satisfy on + + align:start position:0% +on the right when you don't satisfy on + + + align:start position:0% +on the right when you don't satisfy on +the left so it's uh the difference is + + align:start position:0% +the left so it's uh the difference is + + + align:start position:0% +the left so it's uh the difference is +three versus four when these are + + align:start position:0% +three versus four when these are + + + align:start position:0% +three versus four when these are +satisfied you satisfy four on the right + + align:start position:0% +satisfied you satisfy four on the right + + + align:start position:0% +satisfied you satisfy four on the right +when they're unsatisfied you satisfy + + align:start position:0% +when they're unsatisfied you satisfy + + + align:start position:0% +when they're unsatisfied you satisfy +three on the right that's all I'm + + align:start position:0% +three on the right that's all I'm + + + align:start position:0% +three on the right that's all I'm +claiming + + align:start position:0% +claiming + + + align:start position:0% +claiming +so + + align:start position:0% + + + + align:start position:0% + +um so if the equation is + + align:start position:0% + + + + align:start position:0% + +satisfied then we get + + align:start position:0% +satisfied then we get + + + align:start position:0% +satisfied then we get +four uh in the three side + + align:start position:0% +four uh in the three side + + + align:start position:0% +four uh in the three side +instance and if it's + + align:start position:0% + + + + align:start position:0% + +unsatisfied we turn out to get exactly + + align:start position:0% + + + + align:start position:0% + +three okay so I want to prove that this + + align:start position:0% +three okay so I want to prove that this + + + align:start position:0% +three okay so I want to prove that this +is an L reduction to prove L reduction + + align:start position:0% +is an L reduction to prove L reduction + + + align:start position:0% +is an L reduction to prove L reduction +we need two things one is that the + + align:start position:0% +we need two things one is that the + + + align:start position:0% +we need two things one is that the +additive Gap if I solve the three set + + align:start position:0% +additive Gap if I solve the three set + + + align:start position:0% +additive Gap if I solve the three set +instance and convert it back into a + + align:start position:0% +instance and convert it back into a + + + align:start position:0% +instance and convert it back into a +corresponding uh solution to Max e3x + + align:start position:0% +corresponding uh solution to Max e3x + + + align:start position:0% +corresponding uh solution to Max e3x +noret which uh I don't change anything + + align:start position:0% +noret which uh I don't change anything + + + align:start position:0% +noret which uh I don't change anything +the variables are just what they were + + align:start position:0% +the variables are just what they were + + + align:start position:0% +the variables are just what they were +before uh that the additive Gap from opt + + align:start position:0% +before uh that the additive Gap from opt + + + align:start position:0% +before uh that the additive Gap from opt +on the right side is is uh most some + + align:start position:0% +on the right side is is uh most some + + + align:start position:0% +on the right side is is uh most some +constant times the additive gap on the + + align:start position:0% +constant times the additive gap on the + + + align:start position:0% +constant times the additive gap on the +left side vice + + align:start position:0% +left side vice + + + align:start position:0% +left side vice +versa uh in this case the Gap is exactly + + align:start position:0% +versa uh in this case the Gap is exactly + + + align:start position:0% +versa uh in this case the Gap is exactly +preserved because uh it's 4 vers three + + align:start position:0% +preserved because uh it's 4 vers three + + + align:start position:0% +preserved because uh it's 4 vers three +over here it's one versus Z over here so + + align:start position:0% +over here it's one versus Z over here so + + + align:start position:0% +over here it's one versus Z over here so +additive Gap remains + + align:start position:0% +additive Gap remains + + + align:start position:0% +additive Gap remains +one and that is + + align:start position:0% +one and that is + + + align:start position:0% +one and that is +called beta I think in uh in L reduction + + align:start position:0% + + + + align:start position:0% + +land so this was property two in the L + + align:start position:0% +land so this was property two in the L + + + align:start position:0% +land so this was property two in the L +reduction uh so the + + align:start position:0% + + + + align:start position:0% + +additive error in this case is um + + align:start position:0% +additive error in this case is um + + + align:start position:0% +additive error in this case is um +exactly + + align:start position:0% + + + + align:start position:0% + +preserved so there's no scale beta + + align:start position:0% +preserved so there's no scale beta + + + align:start position:0% +preserved so there's no scale beta +equals + + align:start position:0% +equals + + + align:start position:0% +equals +one if there's some other gap than four + + align:start position:0% +one if there's some other gap than four + + + align:start position:0% +one if there's some other gap than four +if it was five versus three then the + + align:start position:0% +if it was five versus three then the + + + align:start position:0% +if it was five versus three then the +we'd have beta equal + + align:start position:0% +we'd have beta equal + + + align:start position:0% +we'd have beta equal +two okay then there was the other + + align:start position:0% +two okay then there was the other + + + align:start position:0% +two okay then there was the other +property which is you need to show that + + align:start position:0% +property which is you need to show that + + + align:start position:0% +property which is you need to show that +you don't blow up opt too much we want + + align:start position:0% +you don't blow up opt too much we want + + + align:start position:0% +you don't blow up opt too much we want +the opt on the right hand side to be at + + align:start position:0% +the opt on the right hand side to be at + + + align:start position:0% +the opt on the right hand side to be at +most some constant times opt on the left + + align:start position:0% +most some constant times opt on the left + + + align:start position:0% +most some constant times opt on the left +hand + + align:start position:0% +hand + + + align:start position:0% +hand +side uh this requires a little bit + + align:start position:0% +side uh this requires a little bit + + + align:start position:0% +side uh this requires a little bit +more care because we need to make sure + + align:start position:0% +more care because we need to make sure + + + align:start position:0% +more care because we need to make sure +opt is linear basically we did a lot of + + align:start position:0% +opt is linear basically we did a lot of + + + align:start position:0% +opt is linear basically we did a lot of +these arguments uh last lecture uh + + align:start position:0% +these arguments uh last lecture uh + + + align:start position:0% +these arguments uh last lecture uh +because even when you don't satisfy + + align:start position:0% +because even when you don't satisfy + + + align:start position:0% +because even when you don't satisfy +things you still get points and the + + align:start position:0% +things you still get points and the + + + align:start position:0% +things you still get points and the +difference between zero and three is Big + + align:start position:0% +difference between zero and three is Big + + + align:start position:0% +difference between zero and three is Big +ratio so we want that to not happen too + + align:start position:0% +ratio so we want that to not happen too + + + align:start position:0% +ratio so we want that to not happen too +much and it doesn't happen too much + + align:start position:0% +much and it doesn't happen too much + + + align:start position:0% +much and it doesn't happen too much +because we know uh the left hand side + + align:start position:0% +because we know uh the left hand side + + + align:start position:0% +because we know uh the left hand side +opt is at least half of all the claes so + + align:start position:0% +opt is at least half of all the claes so + + + align:start position:0% +opt is at least half of all the claes so +it's not like there are very many + + align:start position:0% +it's not like there are very many + + + align:start position:0% +it's not like there are very many +unsatisfied Clauses at most half of them + + align:start position:0% +unsatisfied Clauses at most half of them + + + align:start position:0% +unsatisfied Clauses at most half of them +are unsatisfied cu because at least half + + align:start position:0% +are unsatisfied cu because at least half + + + align:start position:0% +are unsatisfied cu because at least half +are + + align:start position:0% +are + + + align:start position:0% +are +satisfiable in the case of opt uh + + align:start position:0% +satisfiable in the case of opt uh + + + align:start position:0% +satisfiable in the case of opt uh +so here's the full + + align:start position:0% + + + + align:start position:0% + +argument in + + align:start position:0% + + + + align:start position:0% + +general opt for the threat instance is + + align:start position:0% +general opt for the threat instance is + + + align:start position:0% +general opt for the threat instance is +going to be four times all the + + align:start position:0% +going to be four times all the + + + align:start position:0% +going to be four times all the +satisfiable things plus three times all + + align:start position:0% +satisfiable things plus three times all + + + align:start position:0% +satisfiable things plus three times all +the unsatisfiable things this is the + + align:start position:0% +the unsatisfiable things this is the + + + align:start position:0% +the unsatisfiable things this is the +same thing as saying uh the + + align:start position:0% +same thing as saying uh the + + + align:start position:0% +same thing as saying uh the +uh sorry you take three times the number + + align:start position:0% +uh sorry you take three times the number + + + align:start position:0% +uh sorry you take three times the number +of equations every equation gets three + + align:start position:0% +of equations every equation gets three + + + align:start position:0% +of equations every equation gets three +points for free and then if you also + + align:start position:0% +points for free and then if you also + + + align:start position:0% +points for free and then if you also +satisfy them you get one more Point okay + + align:start position:0% +satisfy them you get one more Point okay + + + align:start position:0% +satisfy them you get one more Point okay +so this is an equation on those things + + align:start position:0% +so this is an equation on those things + + + align:start position:0% +so this is an equation on those things +the two Ops and we get plus three times + + align:start position:0% +the two Ops and we get plus three times + + + align:start position:0% +the two Ops and we get plus three times +the number of equations and because + + align:start position:0% +the number of equations and because + + + align:start position:0% +the number of equations and because +there is a 1/2 approximation we know + + align:start position:0% +there is a 1/2 approximation we know + + + align:start position:0% +there is a 1/2 approximation we know +that number of equations uh is at most + + align:start position:0% +that number of equations uh is at most + + + align:start position:0% +that number of equations uh is at most +uh 2 * opt + + align:start position:0% + + + + align:start position:0% + +because opt is at least a half the + + align:start position:0% +because opt is at least a half the + + + align:start position:0% +because opt is at least a half the +number of equations and so this thing is + + align:start position:0% +number of equations and so this thing is + + + align:start position:0% +number of equations and so this thing is +overall at most 6 + 1 7 + + align:start position:0% +overall at most 6 + 1 7 + + + align:start position:0% +overall at most 6 + 1 7 +* opt e3x + + align:start position:0% + + + + align:start position:0% + +nor okay uh and this is the thing called + + align:start position:0% +nor okay uh and this is the thing called + + + align:start position:0% +nor okay uh and this is the thing called +Alpha in L + + align:start position:0% +Alpha in L + + + align:start position:0% +Alpha in L +reduction I wanted to compute these + + align:start position:0% +reduction I wanted to compute these + + + align:start position:0% +reduction I wanted to compute these +explicitly because I want to see how + + align:start position:0% +explicitly because I want to see how + + + align:start position:0% +explicitly because I want to see how +much inapproximability I get because I + + align:start position:0% +much inapproximability I get because I + + + align:start position:0% +much inapproximability I get because I +started with a tight in approximability + + align:start position:0% +started with a tight in approximability + + + align:start position:0% +started with a tight in approximability +Bound of 1 12 minus Epsilon being + + align:start position:0% +Bound of 1 12 minus Epsilon being + + + align:start position:0% +Bound of 1 12 minus Epsilon being +impossible uh whereas 1/2 is possible + + align:start position:0% +impossible uh whereas 1/2 is possible + + + align:start position:0% +impossible uh whereas 1/2 is possible +it's tight up to this very tiny + + align:start position:0% +it's tight up to this very tiny + + + align:start position:0% +it's tight up to this very tiny +arbitrary additive + + align:start position:0% +arbitrary additive + + + align:start position:0% +arbitrary additive +constant uh and over here we're going to + + align:start position:0% +constant uh and over here we're going to + + + align:start position:0% +constant uh and over here we're going to +lose something uh we know from L + + align:start position:0% +lose something uh we know from L + + + align:start position:0% +lose something uh we know from L +reductions if you're inapproximability + + align:start position:0% +reductions if you're inapproximability + + + align:start position:0% +reductions if you're inapproximability +in this case of Max E3 set so what is + + align:start position:0% +in this case of Max E3 set so what is + + + align:start position:0% +in this case of Max E3 set so what is +the factor um if you think of there's uh + + align:start position:0% +the factor um if you think of there's uh + + + align:start position:0% +the factor um if you think of there's uh +one simplif here relative to what I + + align:start position:0% +one simplif here relative to what I + + + align:start position:0% +one simplif here relative to what I +presented before uh a couple lectures + + align:start position:0% +presented before uh a couple lectures + + + align:start position:0% +presented before uh a couple lectures +ago we always thought about 1 plus + + align:start position:0% +ago we always thought about 1 plus + + + align:start position:0% +ago we always thought about 1 plus +Epsilon approximation and how does + + align:start position:0% +Epsilon approximation and how does + + + align:start position:0% +Epsilon approximation and how does +epsilon change um and that works really + + align:start position:0% +epsilon change um and that works really + + + align:start position:0% +epsilon change um and that works really +well for minimization problems for a + + align:start position:0% +well for minimization problems for a + + + align:start position:0% +well for minimization problems for a +maximization problem your approximation + + align:start position:0% +maximization problem your approximation + + + align:start position:0% +maximization problem your approximation +factor is uh more I mean one an + + align:start position:0% +factor is uh more I mean one an + + + align:start position:0% +factor is uh more I mean one an +approximation factor of 1 plus Epsilon + + align:start position:0% +approximation factor of 1 plus Epsilon + + + align:start position:0% +approximation factor of 1 plus Epsilon +means you are at least this thing times + + align:start position:0% +means you are at least this thing times + + + align:start position:0% +means you are at least this thing times +opt and this thing gets awkward to work + + align:start position:0% +opt and this thing gets awkward to work + + + align:start position:0% +opt and this thing gets awkward to work +with uh equivalently with a different + + align:start position:0% +with uh equivalently with a different + + + align:start position:0% +with uh equivalently with a different +notion of Epsilon you can just think of + + align:start position:0% +notion of Epsilon you can just think of + + + align:start position:0% +notion of Epsilon you can just think of +a 1 minus Epsilon approximation and how + + align:start position:0% +a 1 minus Epsilon approximation and how + + + align:start position:0% +a 1 minus Epsilon approximation and how +does epsilon change and in general uh + + align:start position:0% +does epsilon change and in general uh + + + align:start position:0% +does epsilon change and in general uh +for so for maximization problem if you + + align:start position:0% +for so for maximization problem if you + + + align:start position:0% +for so for maximization problem if you +have one minus Epsilon approximation + + align:start position:0% +have one minus Epsilon approximation + + + align:start position:0% +have one minus Epsilon approximation +before the L reduction then afterwards + + align:start position:0% +before the L reduction then afterwards + + + align:start position:0% +before the L reduction then afterwards +you will have a 1 minus Epsilon over + + align:start position:0% +you will have a 1 minus Epsilon over + + + align:start position:0% +you will have a 1 minus Epsilon over +Alpha + + align:start position:0% +Alpha + + + align:start position:0% +Alpha +Beta so for maximization we had one plus + + align:start position:0% +Beta so for maximization we had one plus + + + align:start position:0% +Beta so for maximization we had one plus +Epsilon and then we got 1 plus Epsilon + + align:start position:0% +Epsilon and then we got 1 plus Epsilon + + + align:start position:0% +Epsilon and then we got 1 plus Epsilon +over Alpha Beta with the minuses it also + + align:start position:0% +over Alpha Beta with the minuses it also + + + align:start position:0% +over Alpha Beta with the minuses it also +works out that's a cleaner way to do Max + + align:start position:0% +works out that's a cleaner way to do Max + + + align:start position:0% +works out that's a cleaner way to do Max +Max imization so this was a maximization + + align:start position:0% +Max imization so this was a maximization + + + align:start position:0% +Max imization so this was a maximization +problem we had uh over here Epsilon was + + align:start position:0% +problem we had uh over here Epsilon was + + + align:start position:0% +problem we had uh over here Epsilon was +uh sorry different Notions of Epsilon + + align:start position:0% +uh sorry different Notions of Epsilon + + + align:start position:0% +uh sorry different Notions of Epsilon +here we have one2 in approximability + + align:start position:0% +here we have one2 in approximability + + + align:start position:0% +here we have one2 in approximability +that it 1/2 is also known as 1 minus 1/2 + + align:start position:0% +that it 1/2 is also known as 1 minus 1/2 + + + align:start position:0% +that it 1/2 is also known as 1 minus 1/2 +so Epsilon here is a half um and Alpha + + align:start position:0% +so Epsilon here is a half um and Alpha + + + align:start position:0% +so Epsilon here is a half um and Alpha +was 7 beta was uh 1 and so we just + + align:start position:0% +was 7 beta was uh 1 and so we just + + + align:start position:0% +was 7 beta was uh 1 and so we just +divide by seven so in this case we get + + align:start position:0% +divide by seven so in this case we get + + + align:start position:0% +divide by seven so in this case we get +that Max E3 sat + + align:start position:0% + + + + align:start position:0% + +uh is 1 + + align:start position:0% +uh is 1 + + + align:start position:0% +uh is 1 +minus uh 12 / 7 which is + + align:start position:0% +minus uh 12 / 7 which is + + + align:start position:0% +minus uh 12 / 7 which is +114th technically there's a minus + + align:start position:0% +114th technically there's a minus + + + align:start position:0% +114th technically there's a minus +Epsilon + + align:start position:0% +Epsilon + + + align:start position:0% +Epsilon +here sorry bad use of bad overuse of + + align:start position:0% +here sorry bad use of bad overuse of + + + align:start position:0% +here sorry bad use of bad overuse of +Epsilon this is again for any Epsilon + + align:start position:0% +Epsilon this is again for any Epsilon + + + align:start position:0% +Epsilon this is again for any Epsilon +greater than zero because uh we had some + + align:start position:0% +greater than zero because uh we had some + + + align:start position:0% +greater than zero because uh we had some +Epsilon greater than zero here slightly + + align:start position:0% +Epsilon greater than zero here slightly + + + align:start position:0% +Epsilon greater than zero here slightly +less than 1/2 is impossible so over here + + align:start position:0% +less than 1/2 is impossible so over here + + + align:start position:0% +less than 1/2 is impossible so over here +we get slightly less than 1 - 1 14th is + + align:start position:0% +we get slightly less than 1 - 1 14th is + + + align:start position:0% +we get slightly less than 1 - 1 14th is +impossible this is + + align:start position:0% +impossible this is + + + align:start position:0% +impossible this is +uh uh 13 over + + align:start position:0% +uh uh 13 over + + + align:start position:0% +uh uh 13 over +14 minus + + align:start position:0% + + + + align:start position:0% + +Epsilon uh which is okay it's a bound uh + + align:start position:0% +Epsilon uh which is okay it's a bound uh + + + align:start position:0% +Epsilon uh which is okay it's a bound uh +but it's not a tight bount the right + + align:start position:0% +but it's not a tight bount the right + + + align:start position:0% +but it's not a tight bount the right +answer for Max 3 set is 78 because if + + align:start position:0% +answer for Max 3 set is 78 because if + + + align:start position:0% +answer for Max 3 set is 78 because if +you take a again a uniform random + + align:start position:0% +you take a again a uniform random + + + align:start position:0% +you take a again a uniform random +assignment every variable flips a coin + + align:start position:0% +assignment every variable flips a coin + + + align:start position:0% +assignment every variable flips a coin +heads or tails true or false + + align:start position:0% +heads or tails true or false + + + align:start position:0% +heads or tails true or false +uh then 7/8 of the Clauses will be + + align:start position:0% +uh then 7/8 of the Clauses will be + + + align:start position:0% +uh then 7/8 of the Clauses will be +satisfied in expectation because if you + + align:start position:0% +satisfied in expectation because if you + + + align:start position:0% +satisfied in expectation because if you +look at a clause if it has exactly three + + align:start position:0% +look at a clause if it has exactly three + + + align:start position:0% +look at a clause if it has exactly three +terms and it's an or of three things you + + align:start position:0% +terms and it's an or of three things you + + + align:start position:0% +terms and it's an or of three things you +just need at least one head to satisfy + + align:start position:0% +just need at least one head to satisfy + + + align:start position:0% +just need at least one head to satisfy +this thing so you get a 50% chance to do + + align:start position:0% +this thing so you get a 50% chance to do + + + align:start position:0% +this thing so you get a 50% chance to do +it in the first time and then a quarter + + align:start position:0% +it in the first time and then a quarter + + + align:start position:0% +it in the first time and then a quarter +chance to do it in the third time and + + align:start position:0% +chance to do it in the third time and + + + align:start position:0% +chance to do it in the third time and +general 78 chance to get it one of the + + align:start position:0% +general 78 chance to get it one of the + + + align:start position:0% +general 78 chance to get it one of the +three + + align:start position:0% +three + + + align:start position:0% +three +times uh 78 is smaller than + + align:start position:0% +times uh 78 is smaller than + + + align:start position:0% +times uh 78 is smaller than +1314 so we're not quite there yet but + + align:start position:0% +1314 so we're not quite there yet but + + + align:start position:0% +1314 so we're not quite there yet but +this reduction will do it if we think + + align:start position:0% +this reduction will do it if we think + + + align:start position:0% +this reduction will do it if we think +about it from the perspective of Gap + + align:start position:0% +about it from the perspective of Gap + + + align:start position:0% +about it from the perspective of Gap +preserving + + align:start position:0% +preserving + + + align:start position:0% +preserving +reductions so from this General L + + align:start position:0% +reductions so from this General L + + + align:start position:0% +reductions so from this General L +reduction black box that we only lose an + + align:start position:0% +reduction black box that we only lose an + + + align:start position:0% +reduction black box that we only lose an +alpha beta Factor yeah we get this bound + + align:start position:0% +alpha beta Factor yeah we get this bound + + + align:start position:0% +alpha beta Factor yeah we get this bound +um but from a gap perspective we can do + + align:start position:0% +um but from a gap perspective we can do + + + align:start position:0% +um but from a gap perspective we can do +better the reason we can do better is uh + + align:start position:0% +better the reason we can do better is uh + + + align:start position:0% +better the reason we can do better is uh +because gaps are always talking about + + align:start position:0% +because gaps are always talking about + + + align:start position:0% +because gaps are always talking about +yes instances where lots of things are + + align:start position:0% +yes instances where lots of things are + + + align:start position:0% +yes instances where lots of things are +satisfied that means we're most of the + + align:start position:0% +satisfied that means we're most of the + + + align:start position:0% +satisfied that means we're most of the +time in the case where we have fours on + + align:start position:0% +time in the case where we have fours on + + + align:start position:0% +time in the case where we have fours on +the right hand side + + align:start position:0% +the right hand side + + + align:start position:0% +the right hand side +or a situation where we have lots of + + align:start position:0% +or a situation where we have lots of + + + align:start position:0% +or a situation where we have lots of +things unsatisfied that means we have + + align:start position:0% +things unsatisfied that means we have + + + align:start position:0% +things unsatisfied that means we have +lots of Threes on the right hand side it + + align:start position:0% +lots of Threes on the right hand side it + + + align:start position:0% +lots of Threes on the right hand side it +lets us get a slightly tighter bound so + + align:start position:0% +lets us get a slightly tighter bound so + + + align:start position:0% +lets us get a slightly tighter bound so +let's do + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +that all all right so here is a gap + + align:start position:0% + + + + align:start position:0% + +argument about the same reduction what + + align:start position:0% +argument about the same reduction what + + + align:start position:0% +argument about the same reduction what +we're going to claim is that uh 78 minus + + align:start position:0% +we're going to claim is that uh 78 minus + + + align:start position:0% +we're going to claim is that uh 78 minus +Epsilon uh + + align:start position:0% +Epsilon uh + + + align:start position:0% +Epsilon uh +Gap + + align:start position:0% +Gap + + + align:start position:0% +Gap +threat is nty + + align:start position:0% +threat is nty + + + align:start position:0% +threat is nty +hard which implies 78 in approximability + + align:start position:0% +hard which implies 78 in approximability + + + align:start position:0% +hard which implies 78 in approximability +but by looking at it from The Gap + + align:start position:0% +but by looking at it from The Gap + + + align:start position:0% +but by looking at it from The Gap +perspective we will get this stronger + + align:start position:0% +perspective we will get this stronger + + + align:start position:0% +perspective we will get this stronger +bound versus the 13 over 14 + + align:start position:0% +bound versus the 13 over 14 + + + align:start position:0% +bound versus the 13 over 14 +bound so + + align:start position:0% +bound so + + + align:start position:0% +bound so +uh the proof is by a gap preserving + + align:start position:0% +uh the proof is by a gap preserving + + + align:start position:0% +uh the proof is by a gap preserving +reduction namely that reduction from Max + + align:start position:0% +reduction namely that reduction from Max + + + align:start position:0% +reduction namely that reduction from Max +E3 X norat to + + align:start position:0% +E3 X norat to + + + align:start position:0% +E3 X norat to +uh Max 3at E3 sat I should + + align:start position:0% + + + + align:start position:0% + +say and so the idea is the following + + align:start position:0% +say and so the idea is the following + + + align:start position:0% +say and so the idea is the following +either we have a yes instance or a no + + align:start position:0% + + + + align:start position:0% + +instance if we have a yes instance + + align:start position:0% +instance if we have a yes instance + + + align:start position:0% +instance if we have a yes instance +uh to + + align:start position:0% +uh to + + + align:start position:0% +uh to +the uh equation problem then we know + + align:start position:0% +the uh equation problem then we know + + + align:start position:0% +the uh equation problem then we know +that uh at least 1us Epsilon of the + + align:start position:0% +that uh at least 1us Epsilon of the + + + align:start position:0% +that uh at least 1us Epsilon of the +uh equations are + + align:start position:0% +uh equations are + + + align:start position:0% +uh equations are +satisfiable okay + + align:start position:0% +satisfiable okay + + + align:start position:0% +satisfiable okay +so we have 1 minus Epsilon let's say m + + align:start position:0% +so we have 1 minus Epsilon let's say m + + + align:start position:0% +so we have 1 minus Epsilon let's say m +is the number of + + align:start position:0% + + + + align:start position:0% + +equations in the no instance case of + + align:start position:0% +equations in the no instance case of + + + align:start position:0% +equations in the no instance case of +course we know uh that not too many are + + align:start position:0% +course we know uh that not too many are + + + align:start position:0% +course we know uh that not too many are +satisfied at most 12 plus Epsilon + + align:start position:0% +satisfied at most 12 plus Epsilon + + + align:start position:0% +satisfied at most 12 plus Epsilon +fraction the equations are + + align:start position:0% + + + + align:start position:0% + +satisfiable so uh in both cases I want + + align:start position:0% +satisfiable so uh in both cases I want + + + align:start position:0% +satisfiable so uh in both cases I want +to see what that converts into so on in + + align:start position:0% +to see what that converts into so on in + + + align:start position:0% +to see what that converts into so on in +the yes instance we get uh all four of + + align:start position:0% +the yes instance we get uh all four of + + + align:start position:0% +the yes instance we get uh all four of +those things being satisfied + + align:start position:0% +those things being satisfied + + + align:start position:0% +those things being satisfied +so that means we're going to have uh at + + align:start position:0% +so that means we're going to have uh at + + + align:start position:0% +so that means we're going to have uh at +least 1 - Epsilon time M * 4 Clauses + + align:start position:0% +least 1 - Epsilon time M * 4 Clauses + + + align:start position:0% +least 1 - Epsilon time M * 4 Clauses +satisfied we'll also have Epsilon M * 3 + + align:start position:0% +satisfied we'll also have Epsilon M * 3 + + + align:start position:0% +satisfied we'll also have Epsilon M * 3 +those are the uh unsatisfied and maybe + + align:start position:0% +those are the uh unsatisfied and maybe + + + align:start position:0% +those are the uh unsatisfied and maybe +some of them are actually satisfied but + + align:start position:0% +some of them are actually satisfied but + + + align:start position:0% +some of them are actually satisfied but +this is a lower bound on how many + + align:start position:0% +this is a lower bound on how many + + + align:start position:0% +this is a lower bound on how many +Clauses we + + align:start position:0% + + + + align:start position:0% + +get okay on the other hand in this + + align:start position:0% +get okay on the other hand in this + + + align:start position:0% +get okay on the other hand in this +situation where not too many are + + align:start position:0% +situation where not too many are + + + align:start position:0% +situation where not too many are +satisfied that means we get a a tighter + + align:start position:0% +satisfied that means we get a a tighter + + + align:start position:0% +satisfied that means we get a a tighter +upper bound so we have + + align:start position:0% +upper bound so we have + + + align:start position:0% +upper bound so we have +uh 12 plus Epsilon * m * 4 and then + + align:start position:0% +uh 12 plus Epsilon * m * 4 and then + + + align:start position:0% +uh 12 plus Epsilon * m * 4 and then +there's the rest 12 minus + + align:start position:0% +there's the rest 12 minus + + + align:start position:0% +there's the rest 12 minus +Epsilon uh * + + align:start position:0% +Epsilon uh * + + + align:start position:0% +Epsilon uh * +3 and maybe some of these are not + + align:start position:0% +3 and maybe some of these are not + + + align:start position:0% +3 and maybe some of these are not +satisfied but this is an upper bound on + + align:start position:0% +satisfied but this is an upper bound on + + + align:start position:0% +satisfied but this is an upper bound on +how many Clauses are + + align:start position:0% +how many Clauses are + + + align:start position:0% +how many Clauses are +satisfied in the three set instance + + align:start position:0% +satisfied in the three set instance + + + align:start position:0% +satisfied in the three set instance +versus equations in the uh 3x set + + align:start position:0% +versus equations in the uh 3x set + + + align:start position:0% +versus equations in the uh 3x set +instance + + align:start position:0% +instance + + + align:start position:0% +instance +okay now I just want to uh compute these + + align:start position:0% +okay now I just want to uh compute these + + + align:start position:0% +okay now I just want to uh compute these +so everything's time M and over here we + + align:start position:0% +so everything's time M and over here we + + + align:start position:0% +so everything's time M and over here we +have 4 - 4 Epsilon over here we have + 3 + + align:start position:0% +have 4 - 4 Epsilon over here we have + 3 + + + align:start position:0% +have 4 - 4 Epsilon over here we have + 3 +Epsilon so that is 4 - + + align:start position:0% +Epsilon so that is 4 - + + + align:start position:0% +Epsilon so that is 4 - +Epsilon M and here we have again + + align:start position:0% +Epsilon M and here we have again + + + align:start position:0% +Epsilon M and here we have again +everything is times M so we have uh four + + align:start position:0% +everything is times M so we have uh four + + + align:start position:0% +everything is times M so we have uh four +halves also known as + + align:start position:0% +halves also known as + + + align:start position:0% +halves also known as +two uh plus 4 Epsilon + + align:start position:0% +two uh plus 4 Epsilon + + + align:start position:0% +two uh plus 4 Epsilon +uh plus we have three halves uh minus 3 + + align:start position:0% +uh plus we have three halves uh minus 3 + + + align:start position:0% +uh plus we have three halves uh minus 3 +Epsilon so the epsilons add up to plus + + align:start position:0% +Epsilon so the epsilons add up to plus + + + align:start position:0% +Epsilon so the epsilons add up to plus +Epsilon that much I can see 4 Epsilon + + align:start position:0% +Epsilon that much I can see 4 Epsilon + + + align:start position:0% +Epsilon that much I can see 4 Epsilon +minus 3 Epsilon um and then we have four + + align:start position:0% +minus 3 Epsilon um and then we have four + + + align:start position:0% +minus 3 Epsilon um and then we have four +halves plus three Hales also known as + + align:start position:0% +halves plus three Hales also known as + + + align:start position:0% +halves plus three Hales also known as +seven halves + + align:start position:0% + + + + align:start position:0% + +yes okay so we had a gap four and we get + + align:start position:0% +yes okay so we had a gap four and we get + + + align:start position:0% +yes okay so we had a gap four and we get +this new Gap after when we have a yes + + align:start position:0% +this new Gap after when we have a yes + + + align:start position:0% +this new Gap after when we have a yes +instance we know that there'll be at + + align:start position:0% +instance we know that there'll be at + + + align:start position:0% +instance we know that there'll be at +least as many Clauses satisfied in the + + align:start position:0% +least as many Clauses satisfied in the + + + align:start position:0% +least as many Clauses satisfied in the +three set and there'll be at most this + + align:start position:0% +three set and there'll be at most this + + + align:start position:0% +three set and there'll be at most this +many in the no instance so what we + + align:start position:0% +many in the no instance so what we + + + align:start position:0% +many in the no instance so what we +proved is uh this bound that + + align:start position:0% +proved is uh this bound that + + + align:start position:0% +proved is uh this bound that +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +uh got them in the right order s Hales + + align:start position:0% +uh got them in the right order s Hales + + + align:start position:0% +uh got them in the right order s Hales +is the smaller one 7es plus Epsilon + + align:start position:0% +is the smaller one 7es plus Epsilon + + + align:start position:0% +is the smaller one 7es plus Epsilon +comma 4 minus + + align:start position:0% +comma 4 minus + + + align:start position:0% +comma 4 minus +Epsilon Gap three set + + align:start position:0% +Epsilon Gap three set + + + align:start position:0% +Epsilon Gap three set +E3 + + align:start position:0% + + + + align:start position:0% + +set is NP hard because we had NP + + align:start position:0% +set is NP hard because we had NP + + + align:start position:0% +set is NP hard because we had NP +hardness of the of the gap before we did + + align:start position:0% +hardness of the of the gap before we did + + + align:start position:0% +hardness of the of the gap before we did +this Gap preserving reduction which + + align:start position:0% +this Gap preserving reduction which + + + align:start position:0% +this Gap preserving reduction which +ended up with this new Gap uh this being + + align:start position:0% +ended up with this new Gap uh this being + + + align:start position:0% +ended up with this new Gap uh this being +for no instances as being for yes + + align:start position:0% +for no instances as being for yes + + + align:start position:0% +for no instances as being for yes +instances uh and so if we want to this + + align:start position:0% +instances uh and so if we want to this + + + align:start position:0% +instances uh and so if we want to this +is with the comma notation for the yes + + align:start position:0% +is with the comma notation for the yes + + + align:start position:0% +is with the comma notation for the yes +and no how how what fraction is + + align:start position:0% +and no how how what fraction is + + + align:start position:0% +and no how how what fraction is +satisfied uh if you um convert it back + + align:start position:0% +satisfied uh if you um convert it back + + + align:start position:0% +satisfied uh if you um convert it back +into the C Gap notation you just take + + align:start position:0% +into the C Gap notation you just take + + + align:start position:0% +into the C Gap notation you just take +the ratio between these two things and + + align:start position:0% +the ratio between these two things and + + + align:start position:0% +the ratio between these two things and +ignoring the epsilons this is like 4 / 7 + + align:start position:0% +ignoring the epsilons this is like 4 / 7 + + + align:start position:0% +ignoring the epsilons this is like 4 / 7 +so that + + align:start position:0% +so that + + + align:start position:0% +so that +is 78 or 87th depending on which way + + align:start position:0% +is 78 or 87th depending on which way + + + align:start position:0% +is 78 or 87th depending on which way +you're looking uh so we get also + + align:start position:0% +you're looking uh so we get also + + + align:start position:0% +you're looking uh so we get also +78 Gap sorry I guess + + align:start position:0% +78 Gap sorry I guess + + + align:start position:0% +78 Gap sorry I guess +87th the way I was phrasing it + + align:start position:0% +87th the way I was phrasing it + + + align:start position:0% +87th the way I was phrasing it +before uh is also NP heart and so that + + align:start position:0% +before uh is also NP heart and so that + + + align:start position:0% +before uh is also NP heart and so that +proves there's also a minus Epsilon + + align:start position:0% +proves there's also a minus Epsilon + + + align:start position:0% +proves there's also a minus Epsilon +sorry I should have kept those slightly + + align:start position:0% +sorry I should have kept those slightly + + + align:start position:0% +sorry I should have kept those slightly +different Epsilon but minus 2 Epsilon + + align:start position:0% +different Epsilon but minus 2 Epsilon + + + align:start position:0% +different Epsilon but minus 2 Epsilon +whatever um and so this gives us the + + align:start position:0% +whatever um and so this gives us the + + + align:start position:0% +whatever um and so this gives us the +87th is the best approximation Factor we + + align:start position:0% +87th is the best approximation Factor we + + + align:start position:0% +87th is the best approximation Factor we +can hope for yeah uh and the first + + align:start position:0% +can hope for yeah uh and the first + + + align:start position:0% +can hope for yeah uh and the first +notation isn't it the fraction of + + align:start position:0% +notation isn't it the fraction of + + + align:start position:0% +notation isn't it the fraction of +Clauses so between zero and one oh yeah + + align:start position:0% +Clauses so between zero and one oh yeah + + + align:start position:0% +Clauses so between zero and one oh yeah +four is a little funny uh right I needed + + align:start position:0% +four is a little funny uh right I needed + + + align:start position:0% +four is a little funny uh right I needed +to scale um thank you because the number + + align:start position:0% +to scale um thank you because the number + + + align:start position:0% +to scale um thank you because the number +of Clauses in the resulting thing is + + align:start position:0% +of Clauses in the resulting thing is + + + align:start position:0% +of Clauses in the resulting thing is +actually 4 m not M so everything here + + align:start position:0% +actually 4 m not M so everything here + + + align:start position:0% +actually 4 m not M so everything here +needs to be div divided by + + align:start position:0% +needs to be div divided by + + + align:start position:0% +needs to be div divided by +four won't affect the final ratio but + + align:start position:0% +four won't affect the final ratio but + + + align:start position:0% +four won't affect the final ratio but +this should really be over four and over + + align:start position:0% +this should really be over four and over + + + align:start position:0% +this should really be over four and over +four um so also known + + align:start position:0% +four um so also known + + + align:start position:0% +four um so also known +as + + align:start position:0% +as + + + align:start position:0% +as +uh + + align:start position:0% + + + + align:start position:0% + +78 plus Epsilon comma 1us + + align:start position:0% +78 plus Epsilon comma 1us + + + align:start position:0% +78 plus Epsilon comma 1us +Epsilon now it's a little clearer + + align:start position:0% +Epsilon now it's a little clearer + + + align:start position:0% +Epsilon now it's a little clearer + + align:start position:0% + + + + align:start position:0% + +cool yeah so are there any like see this + + align:start position:0% +cool yeah so are there any like see this + + + align:start position:0% +cool yeah so are there any like see this +piece where we can beat + + align:start position:0% +piece where we can beat + + + align:start position:0% +piece where we can beat +Randomness uh so for Max cut you can + + align:start position:0% +Randomness uh so for Max cut you can + + + align:start position:0% +Randomness uh so for Max cut you can +beat the r Randomness oh cool uh + + align:start position:0% +beat the r Randomness oh cool uh + + + align:start position:0% +beat the r Randomness oh cool uh +Randomness would give you one half the + + align:start position:0% +Randomness would give you one half the + + + align:start position:0% +Randomness would give you one half the +Williamson algorithm gives you like 1 + + align:start position:0% +Williamson algorithm gives you like 1 + + + align:start position:0% +Williamson algorithm gives you like 1 +something so you can beat it by a + + align:start position:0% +something so you can beat it by a + + + align:start position:0% +something so you can beat it by a +constant Factor probably not by more + + align:start position:0% +constant Factor probably not by more + + + align:start position:0% +constant Factor probably not by more +than a constant Factor but yeah Max cut + + align:start position:0% +than a constant Factor but yeah Max cut + + + align:start position:0% +than a constant Factor but yeah Max cut +is an example where you can beat it um I + + align:start position:0% +is an example where you can beat it um I + + + align:start position:0% +is an example where you can beat it um I +think I have the G Williamson bound + + align:start position:0% + + + + align:start position:0% + +here Max cut the best approximation is + + align:start position:0% +here Max cut the best approximation is + + + align:start position:0% +here Max cut the best approximation is +0878 which is better than what you get + + align:start position:0% +0878 which is better than what you get + + + align:start position:0% +0878 which is better than what you get +by random which is a half I + + align:start position:0% +by random which is a half I + + + align:start position:0% +by random which is a half I +guess + + align:start position:0% +guess + + + align:start position:0% +guess +cool all + + align:start position:0% +cool all + + + align:start position:0% +cool all +right uh cool so we get optimal Bound + + align:start position:0% +right uh cool so we get optimal Bound + + + align:start position:0% +right uh cool so we get optimal Bound +for Max E3 Set uh assuming an optimal + + align:start position:0% +for Max E3 Set uh assuming an optimal + + + align:start position:0% +for Max E3 Set uh assuming an optimal +pound for e3x nor Set uh which is from + + align:start position:0% +pound for e3x nor Set uh which is from + + + align:start position:0% +pound for e3x nor Set uh which is from +PCP yeah so I'm sorry can you explain to + + align:start position:0% +PCP yeah so I'm sorry can you explain to + + + align:start position:0% +PCP yeah so I'm sorry can you explain to +me again why we don't get this from the + + align:start position:0% +me again why we don't get this from the + + + align:start position:0% +me again why we don't get this from the +L reduction but we do get it from the + + align:start position:0% +L reduction but we do get it from the + + + align:start position:0% +L reduction but we do get it from the +Gap argument even though the reduction + + align:start position:0% +Gap argument even though the reduction + + + align:start position:0% +Gap argument even though the reduction +is the same reduction uh it's just a it + + align:start position:0% +is the same reduction uh it's just a it + + + align:start position:0% +is the same reduction uh it's just a it +lets us give a a tighter argument in + + align:start position:0% +lets us give a a tighter argument in + + + align:start position:0% +lets us give a a tighter argument in +this case by thinking about yes + + align:start position:0% +this case by thinking about yes + + + align:start position:0% +this case by thinking about yes +instances and no instances separately we + + align:start position:0% +instances and no instances separately we + + + align:start position:0% +instances and no instances separately we +get one thing because this reduction is + + align:start position:0% +get one thing because this reduction is + + + align:start position:0% +get one thing because this reduction is +designed to do different things for yes + + align:start position:0% +designed to do different things for yes + + + align:start position:0% +designed to do different things for yes +and no instances whereas the L reduction + + align:start position:0% +and no instances whereas the L reduction + + + align:start position:0% +and no instances whereas the L reduction +just says generically if you satisfy + + align:start position:0% +just says generically if you satisfy + + + align:start position:0% +just says generically if you satisfy +these parameters Alpha and beta you get + + align:start position:0% +these parameters Alpha and beta you get + + + align:start position:0% +these parameters Alpha and beta you get +some an approximability result on the + + align:start position:0% +some an approximability result on the + + + align:start position:0% +some an approximability result on the +output but uh it's conservative it's a + + align:start position:0% +output but uh it's conservative it's a + + + align:start position:0% +output but uh it's conservative it's a +conservative bound if you just use + + align:start position:0% +conservative bound if you just use + + + align:start position:0% +conservative bound if you just use +properties one and two up here that's + + align:start position:0% +properties one and two up here that's + + + align:start position:0% +properties one and two up here that's +the best you could show but by + + align:start position:0% +the best you could show but by + + + align:start position:0% +the best you could show but by +essentially reanalyzing property one uh + + align:start position:0% +essentially reanalyzing property one uh + + + align:start position:0% +essentially reanalyzing property one uh +but thinking separately about yes and no + + align:start position:0% +but thinking separately about yes and no + + + align:start position:0% +but thinking separately about yes and no +instances this held for all instances we + + align:start position:0% +instances this held for all instances we + + + align:start position:0% +instances this held for all instances we +got a bound of seven but in the yes and + + align:start position:0% +got a bound of seven but in the yes and + + + align:start position:0% +got a bound of seven but in the yes and +the no cases you can essentially get a + + align:start position:0% +the no cases you can essentially get a + + + align:start position:0% +the no cases you can essentially get a +slightly tighter constant + + align:start position:0% +slightly tighter constant + + + align:start position:0% +slightly tighter constant +Y + + align:start position:0% +Y + + + align:start position:0% +Y +Cool all right I want to tell you + + align:start position:0% +Cool all right I want to tell you + + + align:start position:0% +Cool all right I want to tell you +about uh another cool problem + + align:start position:0% + + + + align:start position:0% + +another Gap hardness that you can get + + align:start position:0% +another Gap hardness that you can get + + + align:start position:0% +another Gap hardness that you can get +out of PCP kind of + + align:start position:0% + + + + align:start position:0% + +analysis by some Gap amplification + + align:start position:0% +analysis by some Gap amplification + + + align:start position:0% +analysis by some Gap amplification +essentially uh which is called label + + align:start position:0% +essentially uh which is called label + + + align:start position:0% +essentially uh which is called label +cover + + align:start position:0% + + + + align:start position:0% + +so uh this problem takes a little bit of + + align:start position:0% +so uh this problem takes a little bit of + + + align:start position:0% +so uh this problem takes a little bit of +time to Define uh but there the basic + + align:start position:0% +time to Define uh but there the basic + + + align:start position:0% +time to Define uh but there the basic +point is there are very strong lower + + align:start position:0% +point is there are very strong lower + + + align:start position:0% +point is there are very strong lower +bounds on the approximation Factor so + + align:start position:0% + + + + align:start position:0% + +uh so you're given a bipartite graph no + + align:start position:0% +uh so you're given a bipartite graph no + + + align:start position:0% +uh so you're given a bipartite graph no +weights + + align:start position:0% +weights + + + align:start position:0% +weights +um the bipartition is + + align:start position:0% +um the bipartition is + + + align:start position:0% +um the bipartition is +a and furthermore a can be divided into + + align:start position:0% +a and furthermore a can be divided into + + + align:start position:0% +a and furthermore a can be divided into +K + + align:start position:0% + + + + align:start position:0% + +chunks and so can + + align:start position:0% + + + + align:start position:0% + +be again these are disjoint + + align:start position:0% + + + + align:start position:0% + +unions and let's say + + align:start position:0% +unions and let's say + + + align:start position:0% +unions and let's say +size of a is n size of B is + + align:start position:0% +size of a is n size of B is + + + align:start position:0% +size of a is n size of B is +n and size of each + + align:start position:0% +n and size of each + + + align:start position:0% +n and size of each +AI is also the + + align:start position:0% +AI is also the + + + align:start position:0% +AI is also the +same you don't have to make these + + align:start position:0% +same you don't have to make these + + + align:start position:0% +same you don't have to make these +assumptions but you can so let's make it + + align:start position:0% +assumptions but you can so let's make it + + + align:start position:0% +assumptions but you can so let's make it +a little bit cleaner so in general uh a + + align:start position:0% +a little bit cleaner so in general uh a + + + align:start position:0% +a little bit cleaner so in general uh a +consists of K groups each of size n over + + align:start position:0% +consists of K groups each of size n over + + + align:start position:0% +consists of K groups each of size n over +k b consists of K groups each of size n + + align:start position:0% +k b consists of K groups each of size n + + + align:start position:0% +k b consists of K groups each of size n +overk so that's our you know we have a + + align:start position:0% +overk so that's our you know we have a + + + align:start position:0% +overk so that's our you know we have a +here with these little groups + + align:start position:0% +here with these little groups + + + align:start position:0% +here with these little groups +we have B these little groups and + + align:start position:0% +we have B these little groups and + + + align:start position:0% +we have B these little groups and +there's some edges between + + align:start position:0% + + + + align:start position:0% + +them in general your goal is to + + align:start position:0% +them in general your goal is to + + + align:start position:0% +them in general your goal is to +choose some subset of a let's call it a + + align:start position:0% +choose some subset of a let's call it a + + + align:start position:0% +choose some subset of a let's call it a +prime and some subset of B call it B + + align:start position:0% +prime and some subset of B call it B + + + align:start position:0% +prime and some subset of B call it B +Prime and uh one other thing I want to + + align:start position:0% +Prime and uh one other thing I want to + + + align:start position:0% +Prime and uh one other thing I want to +talk about is called a super + + align:start position:0% +talk about is called a super + + + align:start position:0% +talk about is called a super +Edge so + + align:start position:0% +Edge so + + + align:start position:0% +Edge so +uh and then I'll say what we want out of + + align:start position:0% +uh and then I'll say what we want out of + + + align:start position:0% +uh and then I'll say what we want out of +these subsets that we choose uh imagine + + align:start position:0% +these subsets that we choose uh imagine + + + align:start position:0% +these subsets that we choose uh imagine +Contracting each of these groups these + + align:start position:0% +Contracting each of these groups these + + + align:start position:0% +Contracting each of these groups these +are there are uh n over K items here and + + align:start position:0% +are there are uh n over K items here and + + + align:start position:0% +are there are uh n over K items here and +there are K different + + align:start position:0% +there are K different + + + align:start position:0% +there are K different +groups imagine Contracting each group to + + align:start position:0% +groups imagine Contracting each group to + + + align:start position:0% +groups imagine Contracting each group to +a single vertex so that here's this is + + align:start position:0% +a single vertex so that here's this is + + + align:start position:0% +a single vertex so that here's this is +A1 this is + + align:start position:0% +A1 this is + + + align:start position:0% +A1 this is +B3 um I want to say that there's a super + + align:start position:0% +B3 um I want to say that there's a super + + + align:start position:0% +B3 um I want to say that there's a super +Edge from the group A1 to the group B3 + + align:start position:0% +Edge from the group A1 to the group B3 + + + align:start position:0% +Edge from the group A1 to the group B3 +because there's at least one Edge + + align:start position:0% +because there's at least one Edge + + + align:start position:0% +because there's at least one Edge +between them if I squashed A1 down to a + + align:start position:0% +between them if I squashed A1 down to a + + + align:start position:0% +between them if I squashed A1 down to a +single vertex B3 down to a single vertex + + align:start position:0% +single vertex B3 down to a single vertex + + + align:start position:0% +single vertex B3 down to a single vertex +I would get an edge between them so a + + align:start position:0% +I would get an edge between them so a + + + align:start position:0% +I would get an edge between them so a +super Edge uh AI b a i BJ I should + + align:start position:0% +super Edge uh AI b a i BJ I should + + + align:start position:0% +super Edge uh AI b a i BJ I should +say uh exists if there's at least one + + align:start position:0% +say uh exists if there's at least one + + + align:start position:0% +say uh exists if there's at least one +Edge in uh AI cross + + align:start position:0% +Edge in uh AI cross + + + align:start position:0% +Edge in uh AI cross +bj at least one Edge connecting those + + align:start position:0% +bj at least one Edge connecting those + + + align:start position:0% +bj at least one Edge connecting those +groups groups and I'm going to call such + + align:start position:0% +groups groups and I'm going to call such + + + align:start position:0% +groups groups and I'm going to call such +a super Edge + + align:start position:0% +a super Edge + + + align:start position:0% +a super Edge +covered by a prime B Prime if uh at + + align:start position:0% +covered by a prime B Prime if uh at + + + align:start position:0% +covered by a prime B Prime if uh at +least one of those edges is in this + + align:start position:0% +least one of those edges is in this + + + align:start position:0% +least one of those edges is in this +chosen set so if there's at least one + + align:start position:0% +chosen set so if there's at least one + + + align:start position:0% +chosen set so if there's at least one +Edge + + align:start position:0% + + + + align:start position:0% + +sorry if this uh AI cross BJ these are + + align:start position:0% +sorry if this uh AI cross BJ these are + + + align:start position:0% +sorry if this uh AI cross BJ these are +all the possible edges between those + + align:start position:0% +all the possible edges between those + + + align:start position:0% +all the possible edges between those +groups uh intersects + + align:start position:0% + + + + align:start position:0% + +um a prime cross B + + align:start position:0% +um a prime cross B + + + align:start position:0% +um a prime cross B +Prime and in general I want to cover all + + align:start position:0% +Prime and in general I want to cover all + + + align:start position:0% +Prime and in general I want to cover all +the hyper edges if I can so I would like + + align:start position:0% +the hyper edges if I can so I would like + + + align:start position:0% +the hyper edges if I can so I would like +to have a solution where if there is + + align:start position:0% +to have a solution where if there is + + + align:start position:0% +to have a solution where if there is +some Edge between A1 and B3 then in the + + align:start position:0% +some Edge between A1 and B3 then in the + + + align:start position:0% +some Edge between A1 and B3 then in the +set of vertices I choose a prime and B + + align:start position:0% +set of vertices I choose a prime and B + + + align:start position:0% +set of vertices I choose a prime and B +Prime in the left uh they induce at + + align:start position:0% +Prime in the left uh they induce at + + + align:start position:0% +Prime in the left uh they induce at +least one Edge from A1 to B3 and also + + align:start position:0% +least one Edge from A1 to B3 and also + + + align:start position:0% +least one Edge from A1 to B3 and also +from A2 to B3 because there's a there's + + align:start position:0% +from A2 to B3 because there's a there's + + + align:start position:0% +from A2 to B3 because there's a there's +is an edge that I drew here uh I want + + align:start position:0% +is an edge that I drew here uh I want + + + align:start position:0% +is an edge that I drew here uh I want +ideally to choose the end points of that + + align:start position:0% +ideally to choose the end points of that + + + align:start position:0% +ideally to choose the end points of that +edge or some other Edge that connects + + align:start position:0% +edge or some other Edge that connects + + + align:start position:0% +edge or some other Edge that connects +those two groups yeah so you're choosing + + align:start position:0% +those two groups yeah so you're choosing + + + align:start position:0% +those two groups yeah so you're choosing +subsets a prime of a is there some + + align:start position:0% +subsets a prime of a is there some + + + align:start position:0% +subsets a prime of a is there some +restriction on the subset you choose why + + align:start position:0% +restriction on the subset you choose why + + + align:start position:0% +restriction on the subset you choose why +don't you choose like all of a wait oh + + align:start position:0% +don't you choose like all of a wait oh + + + align:start position:0% +don't you choose like all of a wait oh +okay you're not done yet + + align:start position:0% +okay you're not done yet + + + align:start position:0% +okay you're not done yet +nope that's about half of the + + align:start position:0% + + + + align:start position:0% + +definition it's a lot to say it's not + + align:start position:0% +definition it's a lot to say it's not + + + align:start position:0% +definition it's a lot to say it's not +that complicated of a + + align:start position:0% + + + + align:start position:0% + +problem uh so there's two versions it's + + align:start position:0% +problem uh so there's two versions it's + + + align:start position:0% +problem uh so there's two versions it's +part of what makes it longer we'll start + + align:start position:0% +part of what makes it longer we'll start + + + align:start position:0% +part of what makes it longer we'll start +with the maximization version which is + + align:start position:0% +with the maximization version which is + + + align:start position:0% +with the maximization version which is +called Max rep uh so we have two + + align:start position:0% +called Max rep uh so we have two + + + align:start position:0% +called Max rep uh so we have two +constraints on a prime and B + + align:start position:0% +constraints on a prime and B + + + align:start position:0% +constraints on a prime and B +Prime + + align:start position:0% +Prime + + + align:start position:0% +Prime +uh first is that we choose exactly one + + align:start position:0% +uh first is that we choose exactly one + + + align:start position:0% +uh first is that we choose exactly one +vertex from each group + + align:start position:0% + + + + align:start position:0% + +so uh you know a prime intersect AI + + align:start position:0% +so uh you know a prime intersect AI + + + align:start position:0% +so uh you know a prime intersect AI +equals 1 and B Prime intersect + + align:start position:0% +equals 1 and B Prime intersect + + + align:start position:0% +equals 1 and B Prime intersect +BJ equals 1 for all I and + + align:start position:0% +BJ equals 1 for all I and + + + align:start position:0% +BJ equals 1 for all I and +J + + align:start position:0% +J + + + align:start position:0% +J +okay and then subject to that constraint + + align:start position:0% +okay and then subject to that constraint + + + align:start position:0% +okay and then subject to that constraint +we want to + + align:start position:0% +we want to + + + align:start position:0% +we want to +maximize uh the number of covered super + + align:start position:0% +maximize uh the number of covered super + + + align:start position:0% +maximize uh the number of covered super +edges + + align:start position:0% + + + + align:start position:0% + +okay intuition here is that those groups + + align:start position:0% +okay intuition here is that those groups + + + align:start position:0% +okay intuition here is that those groups +are labels and there's really one super + + align:start position:0% +are labels and there's really one super + + + align:start position:0% +are labels and there's really one super +vertex there and you want to choose one + + align:start position:0% +vertex there and you want to choose one + + + align:start position:0% +vertex there and you want to choose one +of those labels to satisfy the instance + + align:start position:0% +of those labels to satisfy the instance + + + align:start position:0% +of those labels to satisfy the instance +so here you're only allowed to choose + + align:start position:0% +so here you're only allowed to choose + + + align:start position:0% +so here you're only allowed to choose +one label per vertex you choose one out + + align:start position:0% +one label per vertex you choose one out + + + align:start position:0% +one label per vertex you choose one out +of each of the groups then uh you'd like + + align:start position:0% +of each of the groups then uh you'd like + + + align:start position:0% +of each of the groups then uh you'd like +to cover as many edges as you can if + + align:start position:0% +to cover as many edges as you can if + + + align:start position:0% +to cover as many edges as you can if +there is an edge uh in the super graph + + align:start position:0% +there is an edge uh in the super graph + + + align:start position:0% +there is an edge uh in the super graph +from AI to BJ you would like to include + + align:start position:0% +from AI to BJ you would like to include + + + align:start position:0% +from AI to BJ you would like to include +an induced Edge like there should + + align:start position:0% +an induced Edge like there should + + + align:start position:0% +an induced Edge like there should +actually be an edge between the label + + align:start position:0% +actually be an edge between the label + + + align:start position:0% +actually be an edge between the label +you assign to Ai and the label you + + align:start position:0% +you assign to Ai and the label you + + + align:start position:0% +you assign to Ai and the label you +assign to BJ so that's this version the + + align:start position:0% +assign to BJ so that's this version the + + + align:start position:0% +assign to BJ so that's this version the +complimentary problem is a minimization + + align:start position:0% +complimentary problem is a minimization + + + align:start position:0% +complimentary problem is a minimization +problem where we switch what is relaxed + + align:start position:0% +problem where we switch what is relaxed + + + align:start position:0% +problem where we switch what is relaxed +what constraint is relaxed and uh what + + align:start position:0% +what constraint is relaxed and uh what + + + align:start position:0% +what constraint is relaxed and uh what +constraint must hold so here we're going + + align:start position:0% +constraint must hold so here we're going + + + align:start position:0% +constraint must hold so here we're going +to allow multiple labels for each super + + align:start position:0% +to allow multiple labels for each super + + + align:start position:0% +to allow multiple labels for each super +vertex multiple vertices to be chosen + + align:start position:0% +vertex multiple vertices to be chosen + + + align:start position:0% +vertex multiple vertices to be chosen +from each + + align:start position:0% +from each + + + align:start position:0% +from each +group uh instead we force that + + align:start position:0% +group uh instead we force that + + + align:start position:0% +group uh instead we force that +everything is covered we want to cover + + align:start position:0% +everything is covered we want to cover + + + align:start position:0% +everything is covered we want to cover +every Super + + align:start position:0% + + + + align:start position:0% + +Edge that exists and our goal is to + + align:start position:0% +Edge that exists and our goal is to + + + align:start position:0% +Edge that exists and our goal is to +minimize the size of these + + align:start position:0% + + + + align:start position:0% + +sets a prime plus b + + align:start position:0% +sets a prime plus b + + + align:start position:0% +sets a prime plus b +Prime okay so this is sort of the Dual + + align:start position:0% +Prime okay so this is sort of the Dual + + + align:start position:0% +Prime okay so this is sort of the Dual +problem uh here we force one label per + + align:start position:0% +problem uh here we force one label per + + + align:start position:0% +problem uh here we force one label per +vertex want to maximize a number of + + align:start position:0% +vertex want to maximize a number of + + + align:start position:0% +vertex want to maximize a number of +covered things here we force everything + + align:start position:0% +covered things here we force everything + + + align:start position:0% +covered things here we force everything +to be covered want to essentially + + align:start position:0% +to be covered want to essentially + + + align:start position:0% +to be covered want to essentially +minimize the number of labels we + + align:start position:0% + + + + align:start position:0% + +assign okay so these problems are both + + align:start position:0% +assign okay so these problems are both + + + align:start position:0% +assign okay so these problems are both +very hard just to build you some more + + align:start position:0% +very hard just to build you some more + + + align:start position:0% +very hard just to build you some more +intuition uh let me show you a + + align:start position:0% +intuition uh let me show you a + + + align:start position:0% +intuition uh let me show you a +puzzle which is basically exactly this + + align:start position:0% +puzzle which is basically exactly this + + + align:start position:0% +puzzle which is basically exactly this +game uh designed by our MIT Professor + + align:start position:0% +game uh designed by our MIT Professor + + + align:start position:0% +game uh designed by our MIT Professor +Dana + + align:start position:0% +Dana + + + align:start position:0% +Dana +movich uh so here's a word + + align:start position:0% +movich uh so here's a word + + + align:start position:0% +movich uh so here's a word +puzzle uh your goal is to put letters + + align:start position:0% +puzzle uh your goal is to put letters + + + align:start position:0% +puzzle uh your goal is to put letters +into each of these boxes this is B and + + align:start position:0% +into each of these boxes this is B and + + + align:start position:0% +into each of these boxes this is B and +this is a uh and such that for example + + align:start position:0% +this is a uh and such that for example + + + align:start position:0% +this is a uh and such that for example +this says animal which means these the + + align:start position:0% +this says animal which means these the + + + align:start position:0% +this says animal which means these the +three things pointed by the Red Arrows + + align:start position:0% +three things pointed by the Red Arrows + + + align:start position:0% +three things pointed by the Red Arrows +those letters should concatenate to form + + align:start position:0% +those letters should concatenate to form + + + align:start position:0% +those letters should concatenate to form +an animal like uh cat bat all right it's + + align:start position:0% +an animal like uh cat bat all right it's + + + align:start position:0% +an animal like uh cat bat all right it's +the example uh so if I write B A and T + + align:start position:0% +the example uh so if I write B A and T + + + align:start position:0% +the example uh so if I write B A and T +animal is satisfied perfectly uh because + + align:start position:0% +animal is satisfied perfectly uh because + + + align:start position:0% +animal is satisfied perfectly uh because +all three letters form a word I get + + align:start position:0% +all three letters form a word I get + + + align:start position:0% +all three letters form a word I get +three points so far okay next let's + + align:start position:0% +three points so far okay next let's + + + align:start position:0% +three points so far okay next let's +think about + + align:start position:0% +think about + + + align:start position:0% +think about +Transportation uh for example cab is a + + align:start position:0% +Transportation uh for example cab is a + + + align:start position:0% +Transportation uh for example cab is a +three-letter word that is transportation + + align:start position:0% +three-letter word that is transportation + + + align:start position:0% +three-letter word that is transportation +I notice there's always three over here + + align:start position:0% +I notice there's always three over here + + + align:start position:0% +I notice there's always three over here +this corresponds to + + align:start position:0% +this corresponds to + + + align:start position:0% +this corresponds to +uh some regularity constraint on the + + align:start position:0% +uh some regularity constraint on the + + + align:start position:0% +uh some regularity constraint on the +bipart graph there's always going to be + + align:start position:0% +bipart graph there's always going to be + + + align:start position:0% +bipart graph there's always going to be +three arrows going from left to right + + align:start position:0% +three arrows going from left to right + + + align:start position:0% +three arrows going from left to right +for every every + + align:start position:0% +for every every + + + align:start position:0% +for every every +group uh so Transportation fine we got + + align:start position:0% +group uh so Transportation fine we got + + + align:start position:0% +group uh so Transportation fine we got +cab uh that uh is happy we happen to + + align:start position:0% +cab uh that uh is happy we happen to + + + align:start position:0% +cab uh that uh is happy we happen to +reuse the a so we get three more points + + align:start position:0% +reuse the a so we get three more points + + + align:start position:0% +reuse the a so we get three more points +total of six uh Furniture uh is we have + + align:start position:0% +total of six uh Furniture uh is we have + + + align:start position:0% +total of six uh Furniture uh is we have +b blank and T left this is going to be a + + align:start position:0% +b blank and T left this is going to be a + + + align:start position:0% +b blank and T left this is going to be a +little harder I don't know of any + + align:start position:0% +little harder I don't know of any + + + align:start position:0% +little harder I don't know of any +furniture that starts with b and ends + + align:start position:0% +furniture that starts with b and ends + + + align:start position:0% +furniture that starts with b and ends +with t and is three letters long uh but + + align:start position:0% +with t and is three letters long uh but + + + align:start position:0% +with t and is three letters long uh but +if you for example write an e here + + align:start position:0% +if you for example write an e here + + + align:start position:0% +if you for example write an e here +that's pretty close to the word bed + + align:start position:0% +that's pretty close to the word bed + + + align:start position:0% +that's pretty close to the word bed +which is Furniture uh so in general of + + align:start position:0% +which is Furniture uh so in general of + + + align:start position:0% +which is Furniture uh so in general of +course each of these words corresponds + + align:start position:0% +course each of these words corresponds + + + align:start position:0% +course each of these words corresponds +to a set of English words uh that's + + align:start position:0% +to a set of English words uh that's + + + align:start position:0% +to a set of English words uh that's +going to be the uh groups on the left so + + align:start position:0% +going to be the uh groups on the left so + + + align:start position:0% +going to be the uh groups on the left so +this AI group for furniture is a set of + + align:start position:0% +this AI group for furniture is a set of + + + align:start position:0% +this AI group for furniture is a set of +all words that are furniture and three + + align:start position:0% +all words that are furniture and three + + + align:start position:0% +all words that are furniture and three +letters long um and then for each such + + align:start position:0% +letters long um and then for each such + + + align:start position:0% +letters long um and then for each such +choice on the left for each such choice + + align:start position:0% +choice on the left for each such choice + + + align:start position:0% +choice on the left for each such choice +on the right you can say is are they + + align:start position:0% +on the right you can say is are they + + + align:start position:0% +on the right you can say is are they +compatible by either putting an edge or + + align:start position:0% +compatible by either putting an edge or + + + align:start position:0% +compatible by either putting an edge or +not um and so this is uh we got two out + + align:start position:0% +not um and so this is uh we got two out + + + align:start position:0% +not um and so this is uh we got two out +of three of these edges these two were + + align:start position:0% +of three of these edges these two were + + + align:start position:0% +of three of these edges these two were +satisfied this one's not so we get two + + align:start position:0% +satisfied this one's not so we get two + + + align:start position:0% +satisfied this one's not so we get two +more points so for a total of + + align:start position:0% +more points so for a total of + + + align:start position:0% +more points so for a total of +eight okay this is for the maximization + + align:start position:0% +eight okay this is for the maximization + + + align:start position:0% +eight okay this is for the maximization +problem minimization is would be + + align:start position:0% +problem minimization is would be + + + align:start position:0% +problem minimization is would be +different uh here's a verb where we + + align:start position:0% +different uh here's a verb where we + + + align:start position:0% +different uh here's a verb where we +almost get to cry CB y so we get two + + align:start position:0% +almost get to cry CB y so we get two + + + align:start position:0% +almost get to cry CB y so we get two +more points um here is another we want a + + align:start position:0% +more points um here is another we want a + + + align:start position:0% +more points um here is another we want a +verb blank a y there are multiple such + + align:start position:0% +verb blank a y there are multiple such + + + align:start position:0% +verb blank a y there are multiple such +verbs uh can think of them and on the + + align:start position:0% +verbs uh can think of them and on the + + + align:start position:0% +verbs uh can think of them and on the +other hand we have a food which is + + align:start position:0% +other hand we have a food which is + + + align:start position:0% +other hand we have a food which is +supposed to be blank + + align:start position:0% +supposed to be blank + + + align:start position:0% +supposed to be blank +ey uh so a pretty good choice would be P + + align:start position:0% +ey uh so a pretty good choice would be P + + + align:start position:0% +ey uh so a pretty good choice would be P +for that top letter then you get pay + + align:start position:0% +for that top letter then you get pay + + + align:start position:0% +for that top letter then you get pay +exactly and almost get P so a total + + align:start position:0% +exactly and almost get P so a total + + + align:start position:0% +exactly and almost get P so a total +score of 15 uh and so this would be a + + align:start position:0% +score of 15 uh and so this would be a + + + align:start position:0% +score of 15 uh and so this would be a +solution to Max rep of cost uh 15 it's + + align:start position:0% +solution to Max rep of cost uh 15 it's + + + align:start position:0% +solution to Max rep of cost uh 15 it's +not the best and if you start at this + + align:start position:0% +not the best and if you start at this + + + align:start position:0% +not the best and if you start at this +example long enough you can actually get + + align:start position:0% +example long enough you can actually get + + + align:start position:0% +example long enough you can actually get +a perfect solution of score 18 where + + align:start position:0% +a perfect solution of score 18 where + + + align:start position:0% +a perfect solution of score 18 where +there are no violations basically in + + align:start position:0% +there are no violations basically in + + + align:start position:0% +there are no violations basically in +particular you do say here and get soy + + align:start position:0% +particular you do say here and get soy + + + align:start position:0% +particular you do say here and get soy +for + + align:start position:0% +for + + + align:start position:0% +for +food uh so so the sets on the right are + + align:start position:0% +food uh so so the sets on the right are + + + align:start position:0% +food uh so so the sets on the right are +26 letters yes the biis here are the + + align:start position:0% +26 letters yes the biis here are the + + + align:start position:0% +26 letters yes the biis here are the +alphabet A through Z and the sets on the + + align:start position:0% +alphabet A through Z and the sets on the + + + align:start position:0% +alphabet A through Z and the sets on the +left are set of words and then you're + + align:start position:0% +left are set of words and then you're + + + align:start position:0% +left are set of words and then you're +going to connect two of them by an edge + + align:start position:0% +going to connect two of them by an edge + + + align:start position:0% +going to connect two of them by an edge +if that + + align:start position:0% +if that + + + align:start position:0% +if that +that in that letter uh happens to match + + align:start position:0% +that in that letter uh happens to match + + + align:start position:0% +that in that letter uh happens to match +on the right the i letter so it's a + + align:start position:0% +on the right the i letter so it's a + + + align:start position:0% +on the right the i letter so it's a +little I mean the mapping is slightly + + align:start position:0% +little I mean the mapping is slightly + + + align:start position:0% +little I mean the mapping is slightly +complicated but this is a particular + + align:start position:0% +complicated but this is a particular + + + align:start position:0% +complicated but this is a particular +instance of Max + + align:start position:0% +instance of Max + + + align:start position:0% +instance of Max +rep okay + + align:start position:0% +rep okay + + + align:start position:0% +rep okay +so what + + align:start position:0% +so what + + + align:start position:0% +so what +um well we get some super extreme + + align:start position:0% +um well we get some super extreme + + + align:start position:0% +um well we get some super extreme +hardness for these problems + + align:start position:0% +hardness for these problems + + + align:start position:0% +hardness for these problems +so um + + align:start position:0% +so um + + + align:start position:0% +so um +let's start with Epsilon comma + + align:start position:0% +let's start with Epsilon comma + + + align:start position:0% +let's start with Epsilon comma + + align:start position:0% + + + align:start position:0% +Gap uh Max + + align:start position:0% +Gap uh Max + + + align:start position:0% +Gap uh Max +rep is NP + + align:start position:0% + + + + align:start position:0% + +hard + + align:start position:0% +hard + + + align:start position:0% +hard +uh + + align:start position:0% +uh + + + align:start position:0% +uh +yeah so uh what I mean by this is in the + + align:start position:0% +yeah so uh what I mean by this is in the + + + align:start position:0% +yeah so uh what I mean by this is in the +best situation you cover all of the + + align:start position:0% +best situation you cover all of the + + + align:start position:0% +best situation you cover all of the +super edges so the one means 100% of the + + align:start position:0% +super edges so the one means 100% of the + + + align:start position:0% +super edges so the one means 100% of the +super edges are covered + + align:start position:0% +super edges are covered + + + align:start position:0% +super edges are covered +Epsilon means that most Epsilon fraction + + align:start position:0% +Epsilon means that most Epsilon fraction + + + align:start position:0% +Epsilon means that most Epsilon fraction +of them are covered so that problem is + + align:start position:0% +of them are covered so that problem is + + + align:start position:0% +of them are covered so that problem is +empty hard this is a bit stronger than + + align:start position:0% +empty hard this is a bit stronger than + + + align:start position:0% +empty hard this is a bit stronger than +what we had before before we had a + + align:start position:0% +what we had before before we had a + + + align:start position:0% +what we had before before we had a +particular constant comma one or one + + align:start position:0% +particular constant comma one or one + + + align:start position:0% +particular constant comma one or one +minus Epsilon or something uh here for + + align:start position:0% +minus Epsilon or something uh here for + + + align:start position:0% +minus Epsilon or something uh here for +any constant Epsilon this is + + align:start position:0% +any constant Epsilon this is + + + align:start position:0% +any constant Epsilon this is +true and there's a similar result for a + + align:start position:0% +true and there's a similar result for a + + + align:start position:0% +true and there's a similar result for a +Min rep it's just uh from one to one + + align:start position:0% +Min rep it's just uh from one to one + + + align:start position:0% +Min rep it's just uh from one to one +over Epsilon so this means there is no + + align:start position:0% +over Epsilon so this means there is no + + + align:start position:0% +over Epsilon so this means there is no +constant Factor approximation Max rep is + + align:start position:0% +constant Factor approximation Max rep is + + + align:start position:0% +constant Factor approximation Max rep is +not in apx + + align:start position:0% +not in apx + + + align:start position:0% +not in apx +okay but it's worse than that uh we need + + align:start position:0% +okay but it's worse than that uh we need + + + align:start position:0% +okay but it's worse than that uh we need +to assume slightly + + align:start position:0% +to assume slightly + + + align:start position:0% +to assume slightly +more um in general what you can + + align:start position:0% + + + + align:start position:0% + +show if you have some constant P or + + align:start position:0% +show if you have some constant P or + + + align:start position:0% +show if you have some constant P or +there is a constant + + align:start position:0% +there is a constant + + + align:start position:0% +there is a constant +P such + + align:start position:0% + + + + align:start position:0% + +that if you can solve this Gap problem 1 + + align:start position:0% +that if you can solve this Gap problem 1 + + + align:start position:0% +that if you can solve this Gap problem 1 +over P the K so a very tiny fraction of + + align:start position:0% +over P the K so a very tiny fraction of + + + align:start position:0% +over P the K so a very tiny fraction of +things satisfied versus all of the super + + align:start position:0% +things satisfied versus all of the super + + + align:start position:0% +things satisfied versus all of the super +edges covered um + + align:start position:0% +edges covered um + + + align:start position:0% +edges covered um +then + + align:start position:0% +then + + + align:start position:0% +then +NP can be + + align:start position:0% + + + + align:start position:0% + +solved in N to the order K + + align:start position:0% + + + + align:start position:0% + +time uh okay so we haven't usually used + + align:start position:0% +time uh okay so we haven't usually used + + + align:start position:0% +time uh okay so we haven't usually used +this class usually we talk about P which + + align:start position:0% +this class usually we talk about P which + + + align:start position:0% +this class usually we talk about P which +is the union of all these for constant K + + align:start position:0% +is the union of all these for constant K + + + align:start position:0% +is the union of all these for constant K +but here K doesn't have to be a constant + + align:start position:0% +but here K doesn't have to be a constant + + + align:start position:0% +but here K doesn't have to be a constant +it could be some function of N and uh in + + align:start position:0% +it could be some function of N and uh in + + + align:start position:0% +it could be some function of N and uh in +particular if P does not equal NP then K + + align:start position:0% +particular if P does not equal NP then K + + + align:start position:0% +particular if P does not equal NP then K +constant is not possible so this result + + align:start position:0% +constant is not possible so this result + + + align:start position:0% +constant is not possible so this result +implies this + + align:start position:0% +implies this + + + align:start position:0% +implies this +result uh but if we let K get bigger + + align:start position:0% +result uh but if we let K get bigger + + + align:start position:0% +result uh but if we let K get bigger +than a + + align:start position:0% +than a + + + align:start position:0% +than a +constant + + align:start position:0% +constant + + + align:start position:0% +constant +like log log n or something then we get + + align:start position:0% +like log log n or something then we get + + + align:start position:0% +like log log n or something then we get +some separation between uh well we get a + + align:start position:0% +some separation between uh well we get a + + + align:start position:0% +some separation between uh well we get a +a somewhat weaker statement here we know + + align:start position:0% +a somewhat weaker statement here we know + + + align:start position:0% +a somewhat weaker statement here we know +if P does not equal NP we know that NP + + align:start position:0% +if P does not equal NP we know that NP + + + align:start position:0% +if P does not equal NP we know that NP +is not contained in p uh but if we uh + + align:start position:0% +is not contained in p uh but if we uh + + + align:start position:0% +is not contained in p uh but if we uh +furthermore assume that NP doesn't have + + align:start position:0% +furthermore assume that NP doesn't have + + + align:start position:0% +furthermore assume that NP doesn't have +uh subexponential Solutions and very + + align:start position:0% +uh subexponential Solutions and very + + + align:start position:0% +uh subexponential Solutions and very +subexponential Solutions then we get + + align:start position:0% +subexponential Solutions then we get + + + align:start position:0% +subexponential Solutions then we get +various Gap bounds and inapproximability + + align:start position:0% +various Gap bounds and inapproximability + + + align:start position:0% +various Gap bounds and inapproximability +on Max rep so a reasonable limit for + + align:start position:0% +on Max rep so a reasonable limit for + + + align:start position:0% +on Max rep so a reasonable limit for +example is that + + align:start position:0% + + + + align:start position:0% + +uh let's say we assume NP is not + + align:start position:0% + + + + align:start position:0% + +in uh n to the poly log n + + align:start position:0% + + + + align:start position:0% + +n to the poly log n is usually called + + align:start position:0% +n to the poly log n is usually called + + + align:start position:0% +n to the poly log n is usually called +quasi polinomial it's almost polom you + + align:start position:0% +quasi polinomial it's almost polom you + + + align:start position:0% +quasi polinomial it's almost polom you +know log n is kind of close to constant + + align:start position:0% +know log n is kind of close to constant + + + align:start position:0% +know log n is kind of close to constant +is this is the same as two to the poly + + align:start position:0% +is this is the same as two to the poly + + + align:start position:0% +is this is the same as two to the poly +log n uh n to the poly log n but it's a + + align:start position:0% +log n uh n to the poly log n but it's a + + + align:start position:0% +log n uh n to the poly log n but it's a +little clearer this is obviously closer + + align:start position:0% +little clearer this is obviously closer + + + align:start position:0% +little clearer this is obviously closer +close to polinomial quite far from + + align:start position:0% +close to polinomial quite far from + + + align:start position:0% +close to polinomial quite far from +exponential which is 2 to the N not + + align:start position:0% +exponential which is 2 to the N not + + + align:start position:0% +exponential which is 2 to the N not +polog so very different from exponential + + align:start position:0% +polog so very different from exponential + + + align:start position:0% +polog so very different from exponential +so most almost everyone believes NP is + + align:start position:0% +so most almost everyone believes NP is + + + align:start position:0% +so most almost everyone believes NP is +not does not admit quasi polinomial + + align:start position:0% +not does not admit quasi polinomial + + + align:start position:0% +not does not admit quasi polinomial +Solutions they're all problems in NP + + align:start position:0% +Solutions they're all problems in NP + + + align:start position:0% +Solutions they're all problems in NP +would have to admit that threat for + + align:start position:0% +would have to admit that threat for + + + align:start position:0% +would have to admit that threat for +example people don't think you can do + + align:start position:0% +example people don't think you can do + + + align:start position:0% +example people don't think you can do +better than some constant to the + + align:start position:0% +better than some constant to the + + + align:start position:0% +better than some constant to the +N uh then what do we get when we plug in + + align:start position:0% +N uh then what do we get when we plug in + + + align:start position:0% +N uh then what do we get when we plug in +that value of K + + align:start position:0% +that value of K + + + align:start position:0% +that value of K +uh that there is a No 1 over 2 to the + + align:start position:0% +uh that there is a No 1 over 2 to the + + + align:start position:0% +uh that there is a No 1 over 2 to the +log the 1 - Epsilon + + align:start position:0% +log the 1 - Epsilon + + + align:start position:0% +log the 1 - Epsilon +n + + align:start position:0% +n + + + align:start position:0% +n +approximation or also this the same + + align:start position:0% +approximation or also this the same + + + align:start position:0% +approximation or also this the same +thing Gap is + + align:start position:0% +thing Gap is + + + align:start position:0% +thing Gap is +hard now it's not NP hard uh but it's as + + align:start position:0% +hard now it's not NP hard uh but it's as + + + align:start position:0% +hard now it's not NP hard uh but it's as +hard as this problem if you believe this + + align:start position:0% +hard as this problem if you believe this + + + align:start position:0% +hard as this problem if you believe this +is not true then there will be no + + align:start position:0% +is not true then there will be no + + + align:start position:0% +is not true then there will be no +polinomial time algorithm to solve this + + align:start position:0% +polinomial time algorithm to solve this + + + align:start position:0% +polinomial time algorithm to solve this +Factor Gap Max rep so this is very large + + align:start position:0% +Factor Gap Max rep so this is very large + + + align:start position:0% +Factor Gap Max rep so this is very large +this we've seen this before uh in this + + align:start position:0% +this we've seen this before uh in this + + + align:start position:0% +this we've seen this before uh in this +table of various results near the bottom + + align:start position:0% +table of various results near the bottom + + + align:start position:0% +table of various results near the bottom +there was a lower bound of 2 to the log + + align:start position:0% +there was a lower bound of 2 to the log + + + align:start position:0% +there was a lower bound of 2 to the log +to 1us Epsilon n this is not assuming P + + align:start position:0% +to 1us Epsilon n this is not assuming P + + + align:start position:0% +to 1us Epsilon n this is not assuming P +does not equal NP it's assuming this + + align:start position:0% +does not equal NP it's assuming this + + + align:start position:0% +does not equal NP it's assuming this +statement NP does not have quasi + + align:start position:0% +statement NP does not have quasi + + + align:start position:0% +statement NP does not have quasi +polinomial algorithms and you see here + + align:start position:0% +polinomial algorithms and you see here + + + align:start position:0% +polinomial algorithms and you see here +our friends Max and mrep two versions of + + align:start position:0% +our friends Max and mrep two versions of + + + align:start position:0% +our friends Max and mrep two versions of +label + + align:start position:0% +label + + + align:start position:0% +label +cover so uh I'm not going to prove these + + align:start position:0% +cover so uh I'm not going to prove these + + + align:start position:0% +cover so uh I'm not going to prove these +theorems but again there are PCP style + + align:start position:0% +theorems but again there are PCP style + + + align:start position:0% +theorems but again there are PCP style +arguments with some Gap uh + + align:start position:0% +arguments with some Gap uh + + + align:start position:0% +arguments with some Gap uh +boosting uh but I would say most or a + + align:start position:0% +boosting uh but I would say most or a + + + align:start position:0% +boosting uh but I would say most or a +lot of uh approximation lower bounds in + + align:start position:0% +lot of uh approximation lower bounds in + + + align:start position:0% +lot of uh approximation lower bounds in +the world today start from Max rep or + + align:start position:0% +the world today start from Max rep or + + + align:start position:0% +the world today start from Max rep or +Min rep and reduce to the problem using + + align:start position:0% +Min rep and reduce to the problem using + + + align:start position:0% +Min rep and reduce to the problem using +usually some kind of Gap preserving + + align:start position:0% +usually some kind of Gap preserving + + + align:start position:0% +usually some kind of Gap preserving +reduction maybe they lose the Gap but we + + align:start position:0% +reduction maybe they lose the Gap but we + + + align:start position:0% +reduction maybe they lose the Gap but we +have a such a huge gap to start with + + align:start position:0% +have a such a huge gap to start with + + + align:start position:0% +have a such a huge gap to start with +then even if you lose Gap you still get + + align:start position:0% +then even if you lose Gap you still get + + + align:start position:0% +then even if you lose Gap you still get +pretty good results um so a couple of + + align:start position:0% +pretty good results um so a couple of + + + align:start position:0% +pretty good results um so a couple of +quick examples here on the slides uh + + align:start position:0% +quick examples here on the slides uh + + + align:start position:0% +quick examples here on the slides uh +directed Steiner Forest remember you + + align:start position:0% +directed Steiner Forest remember you + + + align:start position:0% +directed Steiner Forest remember you +have a directed graph and you have uh a + + align:start position:0% +have a directed graph and you have uh a + + + align:start position:0% +have a directed graph and you have uh a +bunch of terminal Pairs and you want to + + align:start position:0% +bunch of terminal Pairs and you want to + + + align:start position:0% +bunch of terminal Pairs and you want to +in particular connect via directed path + + align:start position:0% +in particular connect via directed path + + + align:start position:0% +in particular connect via directed path +uh some AIS and B BJs let's say uh and + + align:start position:0% +uh some AIS and B BJs let's say uh and + + + align:start position:0% +uh some AIS and B BJs let's say uh and +you want to do so by choosing uh the + + align:start position:0% +you want to do so by choosing uh the + + + align:start position:0% +you want to do so by choosing uh the +fewest vertices in this graph so what + + align:start position:0% +fewest vertices in this graph so what + + + align:start position:0% +fewest vertices in this graph so what +I'm going to do if I'm given My + + align:start position:0% +I'm going to do if I'm given My + + + align:start position:0% +I'm going to do if I'm given My +bipartite Graph here uh for Min rep I'm + + align:start position:0% +bipartite Graph here uh for Min rep I'm + + + align:start position:0% +bipartite Graph here uh for Min rep I'm +just going to add to represent that this + + align:start position:0% +just going to add to represent that this + + + align:start position:0% +just going to add to represent that this +is a group I'm going to add a Vertex + + align:start position:0% +is a group I'm going to add a Vertex + + + align:start position:0% +is a group I'm going to add a Vertex +here connect by directed edges here and + + align:start position:0% +here connect by directed edges here and + + + align:start position:0% +here connect by directed edges here and +there's a group down here so I'm going + + align:start position:0% +there's a group down here so I'm going + + + align:start position:0% +there's a group down here so I'm going +to have downward edges down there and + + align:start position:0% +to have downward edges down there and + + + align:start position:0% +to have downward edges down there and +whenever there's a super Edge from say + + align:start position:0% +whenever there's a super Edge from say + + + align:start position:0% +whenever there's a super Edge from say +A2 Capital A2 to Capital B1 then I'm + + align:start position:0% +A2 Capital A2 to Capital B1 then I'm + + + align:start position:0% +A2 Capital A2 to Capital B1 then I'm +going to say in my directed Steiner + + align:start position:0% +going to say in my directed Steiner + + + align:start position:0% +going to say in my directed Steiner +Force problem I want a path from Little + + align:start position:0% +Force problem I want a path from Little + + + align:start position:0% +Force problem I want a path from Little +A2 to little B1 so in general whenever + + align:start position:0% +A2 to little B1 so in general whenever + + + align:start position:0% +A2 to little B1 so in general whenever +there's a super Edge I add that + + align:start position:0% +there's a super Edge I add that + + + align:start position:0% +there's a super Edge I add that +constraint and then any solution to + + align:start position:0% +constraint and then any solution to + + + align:start position:0% +constraint and then any solution to +directed Steiner Forest will exactly be + + align:start position:0% +directed Steiner Forest will exactly be + + + align:start position:0% +directed Steiner Forest will exactly be +a solution to mrep you're just forcing + + align:start position:0% +a solution to mrep you're just forcing + + + align:start position:0% +a solution to mrep you're just forcing +the addition of the AIS and bis but it's + + align:start position:0% +the addition of the AIS and bis but it's + + + align:start position:0% +the addition of the AIS and bis but it's +again an L reduction you're just + + align:start position:0% +again an L reduction you're just + + + align:start position:0% +again an L reduction you're just +offsetting by a fixed additive amount so + + align:start position:0% +offsetting by a fixed additive amount so + + + align:start position:0% +offsetting by a fixed additive amount so +your Gap to opt will be the same and so + + align:start position:0% +your Gap to opt will be the same and so + + + align:start position:0% +your Gap to opt will be the same and so +you get that this problem is just as + + align:start position:0% +you get that this problem is just as + + + align:start position:0% +you get that this problem is just as +hard as mrep it's a + + align:start position:0% +hard as mrep it's a + + + align:start position:0% +hard as mrep it's a +yeah uh and well this is another one + + align:start position:0% +yeah uh and well this is another one + + + align:start position:0% +yeah uh and well this is another one +from set cover you can also show node + + align:start position:0% +from set cover you can also show node + + + align:start position:0% +from set cover you can also show node +white weighted Steiner tree is uh log + + align:start position:0% +white weighted Steiner tree is uh log + + + align:start position:0% +white weighted Steiner tree is uh log +and hard to approximate that's not from + + align:start position:0% +and hard to approximate that's not from + + + align:start position:0% +and hard to approximate that's not from +minra but through in there while we're + + align:start position:0% +minra but through in there while we're + + + align:start position:0% +minra but through in there while we're +on the topic of Steiner trees all right + + align:start position:0% +on the topic of Steiner trees all right + + + align:start position:0% +on the topic of Steiner trees all right +I want to mention one more thing + + align:start position:0% +I want to mention one more thing + + + align:start position:0% +I want to mention one more thing +quickly in my zero minutes + + align:start position:0% + + + + align:start position:0% + +remaining and that is uh unique + + align:start position:0% + + + + align:start position:0% + +games so unique games is a special case + + align:start position:0% +games so unique games is a special case + + + align:start position:0% +games so unique games is a special case +of say Max rep or either label cover + + align:start position:0% +of say Max rep or either label cover + + + align:start position:0% +of say Max rep or either label cover +problem where + + align:start position:0% +problem where + + + align:start position:0% +problem where +uh the edges in + + align:start position:0% +uh the edges in + + + align:start position:0% +uh the edges in +AI cross + + align:start position:0% +AI cross + + + align:start position:0% +AI cross +BJ form a + + align:start position:0% + + + + align:start position:0% + +matching okay for every choice on the + + align:start position:0% +matching okay for every choice on the + + + align:start position:0% +matching okay for every choice on the +left there's a unique choice on the + + align:start position:0% +left there's a unique choice on the + + + align:start position:0% +left there's a unique choice on the +right and vice versa that matches + + align:start position:0% +right and vice versa that matches + + + align:start position:0% +right and vice versa that matches +uh well there's at most one choice I + + align:start position:0% +uh well there's at most one choice I + + + align:start position:0% +uh well there's at most one choice I +guess and I think that corresponds to + + align:start position:0% +guess and I think that corresponds to + + + align:start position:0% +guess and I think that corresponds to +these games right if you once you choose + + align:start position:0% +these games right if you once you choose + + + align:start position:0% +these games right if you once you choose +a word over here there's a unique letter + + align:start position:0% +a word over here there's a unique letter + + + align:start position:0% +a word over here there's a unique letter +that matches uh the reverse is not true + + align:start position:0% +that matches uh the reverse is not true + + + align:start position:0% +that matches uh the reverse is not true +so in this problem it's more like a star + + align:start position:0% +so in this problem it's more like a star + + + align:start position:0% +so in this problem it's more like a star +left to right star once you choose this + + align:start position:0% +left to right star once you choose this + + + align:start position:0% +left to right star once you choose this +word uh it's fix what you have to choose + + align:start position:0% +word uh it's fix what you have to choose + + + align:start position:0% +word uh it's fix what you have to choose +on the right side but if you choose a + + align:start position:0% +on the right side but if you choose a + + + align:start position:0% +on the right side but if you choose a +single letter over here it does not + + align:start position:0% +single letter over here it does not + + + align:start position:0% +single letter over here it does not +uniquely determine the word over here so + + align:start position:0% +uniquely determine the word over here so + + + align:start position:0% +uniquely determine the word over here so +unique games is quite a bit stronger you + + align:start position:0% +unique games is quite a bit stronger you + + + align:start position:0% +unique games is quite a bit stronger you +choose either side it forces the other + + align:start position:0% +choose either side it forces the other + + + align:start position:0% +choose either side it forces the other +one if you want to cover that + + align:start position:0% +one if you want to cover that + + + align:start position:0% +one if you want to cover that +edge okay + + align:start position:0% +edge okay + + + align:start position:0% +edge okay +okay so far so good unique games + + align:start position:0% +okay so far so good unique games + + + align:start position:0% +okay so far so good unique games +conjecture is that this special case is + + align:start position:0% +conjecture is that this special case is + + + align:start position:0% +conjecture is that this special case is +also + + align:start position:0% +also + + + align:start position:0% +also +hard unique games + + align:start position:0% +hard unique games + + + align:start position:0% +hard unique games +conjecture is that Epsilon 1 minus + + align:start position:0% +conjecture is that Epsilon 1 minus + + + align:start position:0% +conjecture is that Epsilon 1 minus +Epsilon + + align:start position:0% +Epsilon + + + align:start position:0% +Epsilon +Gap uh unique game is NP + + align:start position:0% +Gap uh unique game is NP + + + align:start position:0% +Gap uh unique game is NP +heart of course there are weaker + + align:start position:0% +heart of course there are weaker + + + align:start position:0% +heart of course there are weaker +versions of this conjecture that don't + + align:start position:0% +versions of this conjecture that don't + + + align:start position:0% +versions of this conjecture that don't +say NP hard maybe assuming some weaker + + align:start position:0% +say NP hard maybe assuming some weaker + + + align:start position:0% +say NP hard maybe assuming some weaker +assumption that there's no polinomial + + align:start position:0% +assumption that there's no polinomial + + + align:start position:0% +assumption that there's no polinomial +time algorithm uh unlike every other + + align:start position:0% +time algorithm uh unlike every other + + + align:start position:0% +time algorithm uh unlike every other +complexity theoretic assumption I have + + align:start position:0% +complexity theoretic assumption I have + + + align:start position:0% +complexity theoretic assumption I have +mentioned in this class this one is a + + align:start position:0% +mentioned in this class this one is a + + + align:start position:0% +mentioned in this class this one is a +subject of much debate not everyone + + align:start position:0% +subject of much debate not everyone + + + align:start position:0% +subject of much debate not everyone +believes that is true some people + + align:start position:0% +believes that is true some people + + + align:start position:0% +believes that is true some people +believe that is false uh many people + + align:start position:0% +believe that is false uh many people + + + align:start position:0% +believe that is false uh many people +believe or basically people don't know + + align:start position:0% +believe or basically people don't know + + + align:start position:0% +believe or basically people don't know +it's a short answer there's uh there's + + align:start position:0% +it's a short answer there's uh there's + + + align:start position:0% +it's a short answer there's uh there's +some somewhat scary evidence that it's + + align:start position:0% +some somewhat scary evidence that it's + + + align:start position:0% +some somewhat scary evidence that it's +not true there are slightly stronger + + align:start position:0% +not true there are slightly stronger + + + align:start position:0% +not true there are slightly stronger +forms of this that are definitely not + + align:start position:0% +forms of this that are definitely not + + + align:start position:0% +forms of this that are definitely not +true uh which I won't get into there is + + align:start position:0% +true uh which I won't get into there is + + + align:start position:0% +true uh which I won't get into there is +a subexponential algorithm for this + + align:start position:0% +a subexponential algorithm for this + + + align:start position:0% +a subexponential algorithm for this +problem but uh it's still up in the air + + align:start position:0% +problem but uh it's still up in the air + + + align:start position:0% +problem but uh it's still up in the air +uh a lot of people like to assume that + + align:start position:0% +uh a lot of people like to assume that + + + align:start position:0% +uh a lot of people like to assume that +this is true because it makes life uh a + + align:start position:0% +this is true because it makes life uh a + + + align:start position:0% +this is true because it makes life uh a +lot more beautiful uh especially from a + + align:start position:0% +lot more beautiful uh especially from a + + + align:start position:0% +lot more beautiful uh especially from a +an approximability standpoint so for + + align:start position:0% +an approximability standpoint so for + + + align:start position:0% +an approximability standpoint so for +example Max the best approximation + + align:start position:0% +example Max the best approximation + + + align:start position:0% +example Max the best approximation +algorithm is 0.94 zero if you assume + + align:start position:0% +algorithm is 0.94 zero if you assume + + + align:start position:0% +algorithm is 0.94 zero if you assume +unique games you can prove a matching + + align:start position:0% +unique games you can prove a matching + + + align:start position:0% +unique games you can prove a matching +lower bound that was Max two set for Max + + align:start position:0% +lower bound that was Max two set for Max + + + align:start position:0% +lower bound that was Max two set for Max +cut uh as was mentioned 878 is the best + + align:start position:0% +cut uh as was mentioned 878 is the best + + + align:start position:0% +cut uh as was mentioned 878 is the best +upper Bound by Gman williamon Williamson + + align:start position:0% +upper Bound by Gman williamon Williamson + + + align:start position:0% +upper Bound by Gman williamon Williamson +this uh if you assume unique games then + + align:start position:0% +this uh if you assume unique games then + + + align:start position:0% +this uh if you assume unique games then +that's also so tight there's a matching + + align:start position:0% +that's also so tight there's a matching + + + align:start position:0% +that's also so tight there's a matching +uh this minus Epsilon or plus Epsilon in + + align:start position:0% +uh this minus Epsilon or plus Epsilon in + + + align:start position:0% +uh this minus Epsilon or plus Epsilon in +approximability + + align:start position:0% +approximability + + + align:start position:0% +approximability +result um and vertex cover two you + + align:start position:0% +result um and vertex cover two you + + + align:start position:0% +result um and vertex cover two you +probably know how to do two if you + + align:start position:0% +probably know how to do two if you + + + align:start position:0% +probably know how to do two if you +assume unique games uh two is the right + + align:start position:0% +assume unique games uh two is the right + + + align:start position:0% +assume unique games uh two is the right +answer if you don't assume anything the + + align:start position:0% +answer if you don't assume anything the + + + align:start position:0% +answer if you don't assume anything the +best we know how to prove using all of + + align:start position:0% +best we know how to prove using all of + + + align:start position:0% +best we know how to prove using all of +this stuff is + + align:start position:0% +this stuff is + + + align:start position:0% +this stuff is +uh + + align:start position:0% +uh + + + align:start position:0% +uh +857 versus + + align:start position:0% +857 versus + + + align:start position:0% +857 versus +0.5 so uh it's nice to assume unique + + align:start position:0% +0.5 so uh it's nice to assume unique + + + align:start position:0% +0.5 so uh it's nice to assume unique +games is true + + align:start position:0% +games is true + + + align:start position:0% +games is true +um very cool result is if you look at + + align:start position:0% +um very cool result is if you look at + + + align:start position:0% +um very cool result is if you look at +over all the different CSP problems that + + align:start position:0% +over all the different CSP problems that + + + align:start position:0% +over all the different CSP problems that +we've seen all the Mac CSP problems and + + align:start position:0% +we've seen all the Mac CSP problems and + + + align:start position:0% +we've seen all the Mac CSP problems and +you try to solve it using a particular + + align:start position:0% +you try to solve it using a particular + + + align:start position:0% +you try to solve it using a particular +kind of semi-definite programming uh + + align:start position:0% +kind of semi-definite programming uh + + + align:start position:0% +kind of semi-definite programming uh +there's an STP + + align:start position:0% +there's an STP + + + align:start position:0% +there's an STP +relaxation if you don't know stps ignore + + align:start position:0% +relaxation if you don't know stps ignore + + + align:start position:0% +relaxation if you don't know stps ignore +the sentence uh there's an STP + + align:start position:0% +the sentence uh there's an STP + + + align:start position:0% +the sentence uh there's an STP +relaxation of all CSP problems you do + + align:start position:0% +relaxation of all CSP problems you do + + + align:start position:0% +relaxation of all CSP problems you do +the sort of obvious thing uh and that + + align:start position:0% +the sort of obvious thing uh and that + + + align:start position:0% +the sort of obvious thing uh and that +STP will have an integrality Gap and if + + align:start position:0% +STP will have an integrality Gap and if + + + align:start position:0% +STP will have an integrality Gap and if +you believe unique games conjecture then + + align:start position:0% +you believe unique games conjecture then + + + align:start position:0% +you believe unique games conjecture then +that integrality Gap equals the + + align:start position:0% +that integrality Gap equals the + + + align:start position:0% +that integrality Gap equals the +approximability + + align:start position:0% +approximability + + + align:start position:0% +approximability +factor one for one and so in this sense + + align:start position:0% +factor one for one and so in this sense + + + align:start position:0% +factor one for one and so in this sense +if you're trying to solve any CSP + + align:start position:0% +if you're trying to solve any CSP + + + align:start position:0% +if you're trying to solve any CSP +problem semi-definite programming is the + + align:start position:0% +problem semi-definite programming is the + + + align:start position:0% +problem semi-definite programming is the +ultimate tool for all approximation + + align:start position:0% +ultimate tool for all approximation + + + align:start position:0% +ultimate tool for all approximation +algorithms uh because if there's a gap + + align:start position:0% +algorithms uh because if there's a gap + + + align:start position:0% +algorithms uh because if there's a gap +in the sdp you can prove an + + align:start position:0% +in the sdp you can prove an + + + align:start position:0% +in the sdp you can prove an +inapproximability result of that minus + + align:start position:0% +inapproximability result of that minus + + + align:start position:0% +inapproximability result of that minus +Epsilon so this is amazingly powerful + + align:start position:0% +Epsilon so this is amazingly powerful + + + align:start position:0% +Epsilon so this is amazingly powerful +the only catch is we don't know whether + + align:start position:0% +the only catch is we don't know whether + + + align:start position:0% +the only catch is we don't know whether +unique games conjecture is true and for + + align:start position:0% +unique games conjecture is true and for + + + align:start position:0% +unique games conjecture is true and for +that reason I'm not going to spend more + + align:start position:0% +that reason I'm not going to spend more + + + align:start position:0% +that reason I'm not going to spend more +time on it but uh this gives you a + + align:start position:0% +time on it but uh this gives you a + + + align:start position:0% +time on it but uh this gives you a +flavor of this this side the field the + + align:start position:0% +flavor of this this side the field the + + + align:start position:0% +flavor of this this side the field the +Gap Gap preservation + + align:start position:0% +Gap Gap preservation + + + align:start position:0% +Gap Gap preservation +approximation any final + + align:start position:0% +approximation any final + + + align:start position:0% +approximation any final +questions + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +yeah uh it's it's fine for a problem to + + align:start position:0% +yeah uh it's it's fine for a problem to + + + align:start position:0% +yeah uh it's it's fine for a problem to +be slightly + + align:start position:0% +be slightly + + + align:start position:0% +be slightly +subexponential it's like 2 to the N to + + align:start position:0% +subexponential it's like 2 to the N to + + + align:start position:0% +subexponential it's like 2 to the N to +to the Epsilon or something so when you + + align:start position:0% +to the Epsilon or something so when you + + + align:start position:0% +to the Epsilon or something so when you +when you do an NP reduction you can blow + + align:start position:0% +when you do an NP reduction you can blow + + + align:start position:0% +when you do an NP reduction you can blow +things up by a polinomial factor and so + + align:start position:0% +things up by a polinomial factor and so + + + align:start position:0% +things up by a polinomial factor and so +so that n to the Epsilon becomes n again + + align:start position:0% +so that n to the Epsilon becomes n again + + + align:start position:0% +so that n to the Epsilon becomes n again +so even if you start from threat where + + align:start position:0% +so even if you start from threat where + + + align:start position:0% +so even if you start from threat where +we don't believe there's a + + align:start position:0% +we don't believe there's a + + + align:start position:0% +we don't believe there's a +subexponential thing uh when you reduce + + align:start position:0% +subexponential thing uh when you reduce + + + align:start position:0% +subexponential thing uh when you reduce +to this you might end up putting it uh + + align:start position:0% +to this you might end up putting it uh + + + align:start position:0% +to this you might end up putting it uh +you you lose that polinomial factor and + + align:start position:0% +you you lose that polinomial factor and + + + align:start position:0% +you you lose that polinomial factor and +so it's not a contradiction yeah bit + + align:start position:0% +so it's not a contradiction yeah bit + + + align:start position:0% +so it's not a contradiction yeah bit +subtle + + align:start position:0% +subtle + + + align:start position:0% +subtle +but cool see you Thursday \ No newline at end of file diff --git a/RITcQMokTJs.txt b/RITcQMokTJs.txt new file mode 100644 index 0000000000000000000000000000000000000000..0fe098e5e68e765487ea84a374ccea20c05162b1 --- /dev/null +++ b/RITcQMokTJs.txt @@ -0,0 +1,3450 @@ +The following +content is provided + +under a Creative +Commons license. + +Your support will help MIT +OpenCourseWare continue + +to offer high quality +educational resources for free. + +To make a donation or +view additional materials + +from hundreds of MIT courses, +visit MIT OpenCourseWare + +at ocw.mit.edu. + +PROFESSOR: Good afternoon. + +The title here is the +topic for our class today. + +We want to discuss formally +the derivation Optical Bloch + +Equations, but usually +when I teach you something, + +I have a general concept in mind +and the concept right now here + +is, how can we get from unitary +time evolution of a quantum + +system to rate +equations anticipation. + +And this is sort of the +subject of master equation + +open system dynamics, and +this cartoon sort of tells you + +what you want to do. + +We have a total system, which is +one part we are interested in, + +and the other one, often it has +many, many degrees of freedom, + +and we don't want to +keep track of them. + +But they have one Hamiltonian. + +But we are only interested in +how our atomic system evolves, + +and we want to find +an equation, which + +is no longer a +Schrodinger equation. + +How does an initial density +matrix describing our system + +develop with time? + +And as we will see, in general, +it follows a master equation, + +and we want to discuss +what are general principles + +of such equations. + +But it's very important +here is that we are not + +keeping track of what +happens in the environment, + +and that's associated here with +a little bucket or trash can. + +Every result photons +or such are measured, + +the environment is constantly +projected on a measurement + +basis, and therefore, +re-introduce probabilistic + +element into the part +we don't observe mainly + +the part which +characterizes the atoms. + +So for that we need the +formalism of density matrix, + +and that's where +we want to start. + +At the end of last +lecture, I reminded you + +that the density +matrix can always + +be written as an +ensemble where you + +say you have a certain +probability for certain rate + +function. + +This is always possible, +but it is not unique. + +So each of you could actually +create the same density matrix + +by preparing a number +of quantum states + +with a certain +probability and saying + +this is my density matrix. + +And also each of you has +prepared different quantum + +states. + +If you sum them up +in that same way, + +you get the same density matrix +and therefore, all observables + +or measurements you will do +on your ensemble in the future + +will be identical because +the density matrix is + +a full description +of the system. + +So at that level, it may +look sort of very trivial + +that we have +different unraveling. + +Unraveling means you +look microscopically + +what is behind the +density matrix, + +but in your homework +assignment, you + +will all show that you can have +a system which have very, very + +different dissipation +mechanisms, + +but they're described +by the same equation. + +So therefore, it's +physically not possible + +to distinguish by just measuring +the density matrix what + +causes a dissipation. + +Of course, if you know +what causes a dissipation, + +fluctuating fields +or collisions, + +you know more than the +density matrix knows. + +Any questions about density +matrix or the agenda + +we want to go through today? + +Just a quick reminder and +since this was covered in 8421, + +and most of you know about +it, I pre-wrote the slides. + +The density matrix +is a time evolution. + +There is one which is sort +trivial and covered in more + +elementary takes, and this +is the Hamiltonian evolution, + +and I'm sure you've seen it. + +The time evolution, the +unitary time evolution + +involves the commutative +of the Hamiltonian + +with a density matrix, +and later on, we + +want to specialize including +dissipation, including + +the environment to the evolution +of a tool evolutionary system + +driven by a monochromatic field + +And this the famous +Jaynes-Cummings Hamiltonian, + +and we can characterize this +system by a density matrix, + +but will be very important +is that we distinguish + +between populations, +the diagonal parts, + +and the coherences. + +And if you simply put +this density matrix + +into this equation, you find the +time evolution of the system, + +and we will refer to +that result later on. + +Many of you have +seen it in 8421. + +we can parametrize +the density matrix + +for the two-level system. + +So we can parametrize +the densities + +of the two-level system +by a local vector, + +r, which is defined +by this equation. + +And then the equation +of motion is simply + +the rotation of a Bloch +vector on the Bloch sphere, + +and it has a +rotational axis, which + +is given by-- the +undriven system + +rotates around the z-axis. + +This is just e to +the i omega naught + +t, the normal evolution +of the free system. + +But if you divide it with +a monochromatic field + +rotation over the x-axis +and the x-axis, of course, + +can take your two-level system, +and flip it from the ground + +to the excited state. + +So it's just a reminder of the +simple unitary time evolution, + +but now we want to add +dissipation on top of it. + +And what I've decided +that before I discuss + +with you Optical Bloch Equation +and master equation in general, + +I want to give you +a very simple model. + +I really like +simple models which + +capture the essence of what +you are going to discuss. + +So what I want to use is I +want to use a beam splitter + +model I formulated for photons, +but it would also immediately + +apply to atoms. + +And this model, what +I like about it, + +it has all the ingredients +of integration of the master + +equation we'll do later +on without the kind + +of many indices and +summations and integration, + +but it captures every single +bit of what is important. + +And I usually like to present +exactly solvable, simple models + +where you get it, and +then I can go a little bit + +faster for the +general derivation + +because you know exactly what +the more complicated equations, + +what they are doing. + +So in other words, what I +want to derive for you is + +we want to have the +following situation. + +We have a beam splitter, +and we know everything + +about beam splitters +because we talked about them + +in the first part of +the course, and we + +have a wave function, +which is the input, + +and this is a photon. + +And we want to understand +after the beam splitter, + +how has the system evolved. + +In general, it will +be a density matrix, + +and what you want +to find out is, + +what is the equation +for the density matrix. + +Maybe this density matrix goes +through the next beam splitter + +and then we want to know +what comes out of it. + +And all we have to +apply is the formalism + +we developed for the beam +splitter earlier in the course. + +Of course, the beam +splitter is not as harmless + +as it looks like. + +There is another part +and another part one here + +brings in the environment, +and for the environment, + +we will use the vacuum. + +That's the simplest environment. + +It's actually +important environment + +because it is the environment +we will use all the time when + +we discuss spontaneous emission. + +We send photons into the +nirvana, into the vacuum + +and they disappear, and +this is our modified. + +But the other one which +is often not so explicit. + +If you send your +photons away, you're + +not keeping track +of what happens, + +but you could as well +perform a measurement, + +and this is what we put in here. + +We say those photons +hit a bucket or detector + +and measure them, +we observe them. + +There's nothing else +we do with them, + +so we can as well measure them, +and this being immediately + +lead to the equation +for the density matrix. + +So this is what you +want to discuss, + +and it will have all +the ingredients later + +on in a mathematically +simple form + +for the derivation +of master equation. + +So let's consider a +similar photon for that. + +So the wave function, +this is superposition + +of no photon and 1 photon, +and the coefficients + +are alpha and beta. + +And just for +simplifying notation, + +I pick alpha and +beta to be real. + +So what do we expect to +happen at the beam splitter? + +Well, there's a probability +that the photon gets reflected. + +Probability to +reflect the photon + +and therefore to +observe the photon. + +This probability is, of course, +beta square-- the probability + +that we have a photon to +begin with-- and then the beam + +splitter, remember we +categorized the beam + +splitter with angle +sine theta cosine theta. + +Sine theta was the +reflection amplitude, + +cosine theta, the +transmission amplitude. + +So this probability, +which I call P1 + +is the probability for +reflection and for measurement. + +And now naively you +would think what + +happens after the system +has passed through the beam + +splitter, with a probability of +P1, we've measured the photon. + +We know for sure there +is no photon left. + +The system is in +the vacuum state, + +but then you would say, +well, maybe with probability + +1 minus P1, we have +not measured anything. + +Nothing has happened +to the wave function, + +and that means the wave +function just continuous. + +Well as we will +see, this is wrong. + +We are missing something. + +What we are actually missing +is that if you measure nothing, + +the wave function is not sine. + +The possibility that we could +have measured something, + +changes the wave function. + +I will comment on that in much +more detail in a few lectures + +down the road when +I derive for you + +quantum Monte Carlo +wave function. + +I will have a wonderful +discussions with you + +about how does non-observation +change a wave function. + +So we will talk about +the physics behind it + +in some more detail. + +Right now, I don't want to +get into this discussion. + +I simply want to use our +beam splitter equation, + +so we can just take the beam +splitter equation and apply it. + +So our output state +is obtained by taking + +the operator for +our beam splitter, + +and maybe you remember that the +propagation for beam splitter + +was discovered by +an operator, which + +had a dagger b dagger +a in the exponent. + +a and b are the two input nodes. + +And the angle of +the beam splitter, + +which interpolates between +0% and 100% reflection + +transmission is theta. + +And we're now looking +for the output + +state of the total system. + +We're not performing +the measurement yet, + +and this is now acting on +the total system, which + +is the cross product +of our photon system, + +of our system of interest. + +And the other +input, which we call + +the environment or +the vacuum, is 0. + +Well, look a few weeks +back, we have done that all. + +The output state is, well, +there was a probability, alpha, + +that we had no photon +in the state psi. + +And if we have no +photon in the state psi + +and no photon in the vacuum, +this is the state 0, 0. + +What I denote here +with this second place + +is the environment. + +And now we have one photon. + +We have exactly one photon +with the amplitude beta, + +and this photon is split +with cosine theta transmitted + +and with phi theta reflected. + +If you transmit +it, we have 1, 0. + +If we reflect it, we have 0, 1. + +And again, this is +the environment, + +and here is a photon +in the environment. + +So let me just be +clear that this + +is where the +environment comes in. + +It is a vacuum +state, and here, this + +is the output part +for the environment. + +This is where we +do the measurement. + +And I don't think it matters. + +I haven't really told you +which is mode A, which + +is mode B. It doesn't +matter, but one, let's say + +the environment is +mode B, and the system + +evolves in mode +A. As you can see, + +I'm using a new +program, which has + +some nicer features in +terms of handwriting, + +but it is a little bit +rough in scrolling, + +so I sometimes have to +scroll back and forth. + +So what is our output? + +Now, we have two possibilities. + +The environment is 0, +or the environment is 1, + +and we perform a measurement. + +So we have to now go into a +probabilistic description. + +So with probability P1, we +have done a measurement, + +and our output state is +now the vacuum state. + +With probability 1 +minus P1, we have not + +detected anything in the +vacuum, and therefore, our state + +of the system is alpha 0 +plus beta cosine theta 1. + +Is alpha 0, so it is not beta 1 +as naively would have assumed. + +It's not the original state. + +There is a cosine theta +factor, which we got exactly + +from the beam splitter from +the unitary evolution provided + +by the beam splitter. + +And since these state +is no longer normalized, + +I have to normalize +it by alpha squared + +plus beta square +cosine square theta. + +So now we have done our +measurement probability P1 + +to detect the photon. + +This projects the system +into the vacuum state + +with the probability 1 minus P1. + +We have that state. + +Just one second. + +Scroll in the pictures. + +Write that down. + +In fact, millions +that our system is now + +described by a density +matrix with probability P1 + +and 1 minus 1 minus P1. + +With probability P1, we +are in the vacuum state, + +and with probability +1 minus P1, we + +are in that state, the +denormalized state psi + +naught, which I just hold down. + +Question? + +AUDIENCE: Have you +considered theta + +to be some like a dynamical +phase evolution system. + +It's very low order +like when you expand it + +the first time it looks almost +identical to [INAUDIBLE] + +quantum effect maybe. + +The environment is measuring the +state in some way, and I mean, + +it's the lowest order now. + +PROFESSOR: Yeah, I Quite +agree that random 0 is just + +an example of it. + +Pretty much, it's all the same. + +Yeah. + +What we do here is, I +like the beam splitter + +because the beam splitter +provides an exact formulation + +of the measurement process. + +You really can use +a beam splitter + +to discuss what +happens fundamentally + +when you perform a measurement. + +And the beams splitter is one +typical implementation of that, + +but it has all the +features you'll + +find in any measurement system. + +And especially what +you observe here, + +let me just emphasizes is, +the fact that we you do not + +make a measurement +is changing the way + +function from the initial wave +function psi to psi naught, + +we have a factor of +cosine theta here. + +And that's also very general. + +A measurement perturbs, +modifies your wave function + +no matter what the outcome +of the measurement is. + +So let me write +it down because we + +want to take it +to the next level. + +So we have now found in terms of +the beam splitter, angle theta, + +and the parameters of the +initial state, alpha beta. + +We found the density matrix +after the beam splitter. + +Yes. + +So what is the next step? + +Our goal is to derive the +master equation for the density + +matrix, the time evolution +of the density matrix. + +So since we want to +discuss the time evolution, + +we want to find a +differential equation. + +So what we want +to figure out is, + +what is the difference +between the output density + +matrix and the input +density matrix. + +The input was, of +course, pure state + +characterized by the matrix +population alpha squared + +and beta squared of diagonal +matrix element of alpha beta. + +The difference between +the density matrix + +is can just calculate +the difference. + +You can simplify +things by applying + +some trigonometric +identities, so this + +is an exact result, +cosine theta minus 1. + +Here we have alpha beta +cosine theta minus 1, + +and on the diagonal, +we have cosine + +2 theta minus 1 divided by 2. + +Anyway this is an +intermediate result. + +We're interested in the +differential equation. + +We want to sort of find out +what happens when we observe, + +when we have the density +matrix interacting + +with the environment +all the time. + +And this can be simulated +by beam splitters + +by using many beam splitters +with a small degree + +of reflection. + +So we want to simplify +this result now + +for the case of many beam +splitters, and each of them + +has a small tipping +angle, theta, + +and for later convenience, I +defined theta to be gamma times + +delta t over 2. + +That's just my +definition of theta. + +So what we have in mind now is +that we start with the system + +psi, and we have many such beam +splitters with an infinitesimal + +tipping angle. + +Each beam splitter has the +vacuum at its input state. + +And we always perform +the measurement. + +If I take the +equation above, which + +I know you can't see anymore, +we find a differential equation + +for the density matrix, which is +we find an infinitesimal change + +delta over the density +matrix, which looks like this. + +So all I've done is, I've +used the equation above, + +and I've done a Taylor expansion +in the small angle theta. + +And the reason why I brought +in the square root, well, + +we get cosine theta. + +The first order Taylor expansion +or the lowest order Taylor + +expansion from cosine is +1 minus theta squared. + +So I get the square +root squared. + +So I get gamma, +which appears here, + +and then I divide by delta t. + +So this is just an exact +mathematical expression, + +and the next step is to form +a differential equation. + +But before I do that, I want +to emphasize the two features + +we are using here. + +They sort of enter +automatically, + +but these are the +two big assumptions + +we make when we derive +a master equation. + +The first one is that we +always have a vacuum state + +as the input. + +So in other words, +the environment + +is always in the same state, +which is a vacuum state, + +and this is sort of called +a Bohr approximation. + +What it means is that we +do a measurement here, + +but the vacuum is not changing. + +In other words, we are +not overloading the vacuum + +with so many photons +that suddenly the vacuum + +Is no longer in +the vacuum state. + +Or in the case of +spontaneous emission, + +the vacuum can just take as many +photons as you dumping into it. + +They disappear so quickly that +for all practical purposes, + +the environment stays +in the vacuum state. + +So this is called the +Bohr approximation. + +The environment is not changing. + +It has enough capacity you to +be modified by the measurement + +process. + +And the second thing +which is related + +is, the vacuum is always +in the same state, + +and there are no correlations +from here to here to here, + +there is no memory effect. + +Everything is +completely uncorrelated. + +So the environment +is uncorrelated. + +It has no memory. + +It's correlation function +is a delta function, + +and this is called +Markov approximation. + +So these are the two +effects which are important. + +One is no memory +for the environment, + +Delta function correlation, +Markov approximation, + +and the two, of +course, are related + +in the environment is all +of this in the same state. + +So remember this is a change +for the density matrix, + +and alpha beta where +the original parameters + +of the density matrix +for the input state. + +So I can now rewrite everything +as a differential equation. + +The density matrix +has a derivative + +for the diagonal matrix +elements and for the coherences. + +Here we have plus gamma. + +Here we have minus +gamma 0, 1, 1, + +makes sense because +we conserve the trace. + +We have unity probability +that we have a stellar system. + +And therefore the two +diagonal matrix elements, + +the population, the sum of +them cannot change with time. + +And for the coherence, +we have gamma over 2. + +And if you're familiar with +Optical Bloch Equations, which + +we derive next, we +can say that these + +means if 0 is the ground state +that the ground state changes + +because-- call it spontaneous +emission from the excited + +state. + +This equation would say that +the excited state decays + +with the rate gamma, +and sometimes you + +may have wondered about +that there are factors + +of two appearing, +which also appears here + +that when the excited state +decays with a rate gamma, + +we have a factor here +for the coherences, which + +is gamma over 2. + +So what we have +accomplished in contrast + +to let's say Einstein's +equation with the Einstein + +a and b coefficient, +which lead to rate + +equations for the population, +we have now a new feature. + +We have an the equation +for the coherences, + +and we find a decay +of the coherences + +with half the rate as a +decay of the population. + +Questions? + +So if you want you could rewrite +this model for photon, which + +goes through beam splitters, +undergoes measurement. + +You can rewrite it from +atomic wave function + +and you measure +whether the atomics + +in the excited and ground +state and the equation + +for the measurement +performed on the atom + +is exactly as the equation by +which the beam splitter acts + +on the photon state. + +So what I've shown +here it's very + +specific for a single +photon because I + +could use simple +equations, but everything + +is what you find in a much +more general situation. + +So before I give you the +general derivation of the master + +equation, let me talk +about what we have learned + +from this example and what +the general procedure is. + +The first thing is our goal +is to find a differential + +equation for the density +matrix of the system. + +I just remember. + +There was one thing +I wanted to mention. + +In the previous derivation +with the beam splitter, + +I started with a purer +state, and the purer state + +developed into a +statistical mixture, + +and this statistical +mixture would then + +transform the next +beam splitter into + +another statistical mixture. + +I derived the differential +equation for you + +for the first state +from the pure state + +to the statistical mixture. + +But if you would +spend a few minutes, + +you could immediately +show that you + +can start with an +elementary density matrix, + +look how it evolves +through the beam splitter, + +and you get exactly the +same differential equation. + +So the general procedure is, +we want a differential equation + +how the density matrix +evolves with time. + +And this will be obtained +by finding an operator which + +acts on the initial +density matrix. + +This operator is not +a unitary operator + +because we are +performing measurements + +through the environment, +even if you don't actually + +perform them. + +Once we dump something +into the environment, + +it's out of our +control and anybody + +could go and perform +a measurement, + +and so we should assume +that this measurement has + +been taken. + +It's one of those +quantum mechanical things + +that you don't even have to +care whether somebody does it. + +The environment does it for you. + +So this operator is called +a Liouvillian operator. + +It's sometimes called-- +and I haven't really + +traced down why-- it's called +sometimes super operator. + +I know what +superconductivity is, + +but I don't know what the super +powers of this operator are, + +but that's just a name +which you will find. + +The second thing +which we have used + +is that the evolution +of this system + +can be obtained from the time +evolution of the total system + +by performing a trace over +the degrees of freedom + +of the environment. + +This was exactly +what we actually + +did when we said the system +continues with probability P + +naught in one state +and probability + +P1 in the other state. + +The operation which lead +to this density matrix + +was exactly the partial trace. + +So this is the second +general feature + +which we have to implement. + +Thirdly, if we could +do one and two exactly, + +we would have an +exact formulation + +for a small part +of a quantum system + +no matter how complicated +the environment is. + +In practice, we can +solve the equations only + +when we make +simplifying assumptions + +about the environment. + +One is, it is large, +and more important, + +therefore, it's unchanging, and +this is the Bohr approximation. + +And the second feature is, +it has a short correlation + +time, tau c. + +In the beam splitter, I +have made the assumption + +that there is no correlation +between different beam + +splitters in the +derivation, which + +I want to walk you through. + +Right now, you +will see explicitly + +where the correlation +times enter. + +And this is called the +Markov approximation. + +And finally, this is number +four, the whole possibility + +to derive a master +equation hinges on the fact + +that we have different +time scales which + +are very different. + +We are interested in the +evolution of our system. + +We want to know how it relaxes, +and this is on a time scale + +1 over gamma. + +So we call this slow. + +We are interested +in the variation + +of our system, the atomic +system or the photon state, + +which passes through +the beam splitter, + +and this time scale +has to be much slower + +than the fluctuations +of the environment. + +So therefore, if the +environment has fluctuations, + +which in the beam +splitter model where + +assumed to be 0, it was +delta function of time, + +if that correlation time is +much smaller than the time + +it takes for the system +to relax and to evolve, + +that opens a window +delta t, and this + +is the time scale of +the master equation. + +Just to give you one example +for the spontaneous emission, + +the correlation +time, tau c, would + +be the time it takes the photon +to disappear from the atom. + +And the photon has +disappeared from the atom + +when it is one wavelengths away. + +So typically, the +correlation time + +f the vacuum for +spontaneous emission + +is one cycle of the +optical frequency. + +It's very, very fast. + +Whereas typical decay times +of the excited states, + +a nano second. + +It's six orders of +magnitude slower, + +and this is what we describe. + +But on a time scale +of a femtosecond + +of one optical cycle, the photon +has not detached from the atom + +and it could go actually +back to the atom. + +During that time, we talked +a little bit about it + +when we did this diagrammatic +discussions of resonance + +scattering for very, +very early times. + +You don't have exponential +decay because you cannot do + +the approximations where +we approximated the kernel + +by something which was +completely energy dependent. + +And so what happens +at such short times, + +we encounter here again +in such short times, + +we will not have a simple +description of the system. + +So the last point, +let me summarize. + +Our goal is that we describe the +density matrix of the system, + +and we want to find +the Liouville operator + +or some matrix which acts on it. + +And because we will integrate +over time steps, which + +are larger than the +correlation time of the system, + +we can also call it, it will +be a coarse-grained evolution. + +Any questions about that? + +I really like the discussion, +the derivation of the master + +equation, how it is presented +in atom-photon indirection. + +But it is presented +on more than 50 pages + +with many, many equations. + +So after giving you all +of the principles, all + +of the concepts, I +want to go with you now + +over those equations +and point out how + +the principles, which we +encountered with the beam + +splitter, how they +are now implemented + +in a very general context. + +I will not be able to give you +all of the mathematical aspects + +of it, but I think by now you +know that the book atom-photon + +interactions are +actually wonderful. + +You can get a lot of conception +information out of it + +by looking at the equations +without understanding + +every technical detail. + +So I would really encourage +you, if there is something which + +piques your interest and I +hope there will be things which + +you'll find very interesting, +that you go to the book + +and read it. + +So I'm exactly following +that actually I + +used copies of the book. + +So we have a +Hamiltonian, which is + +describing the atomic system. + +It describes the reservoir and +then there is an interaction. + +We keep it very general here, +but you may always think well, + +the atom is your favorite +two-level system. + +The environment is +maybe the vacuum + +with all its possible +modes, and the interaction + +is the dipole interaction +or the a dot p interaction. + +So we start out +with an equation, + +which is nothing else +than Schrodinger's + +equation for the density matrix. + +The time derivation +of the density matrix + +is commutative +with the Hamilton. + +But it is often useful and +you've seen it many times, + +to go to the interaction +representation, + +that the time dependence +due to the unperturbed part + +of the operator is absorbed +in a unitary transformation, + +so therefore, this density +matrix in the interaction + +representation evolves not with, +h, because h naught is taken + +care of, it only involves due +to the coupling between the two + +systems, between the +system and the environment. + +So now this equation, we are +interested in a time step delta + +t. + +And this time step, +delta t remember, + +we want to coarse +grain, will be larger + +than the correlation +time of the reservoir, + +and you will see exactly +where it comes about. + +So we want to now do one of +those coarse-grain steps. + +We take this equation and +we integrate from time t + +to time t plus delta t. + +So this is exact here. + +But now we want to iterate, +and that means the following. + +We have expressed the time +step in the density matrix + +by having the +density matrix there. + +But now we can do in a +first-order perturbation + +theory, we can do one step and +we get the second order result + +by plugging the first order +result into this equation. + +It's the same we have seen +with our diagrams and such. + +We have an exact equation. + +It's useless unless we do +something, and what we do is, + +we realize that +we can iterate it + +because the part we don't +know involves one more + +occurrence of the +interaction potential. + +And when you plug the nth +order solution in here, + +you get the n plus +first order solution. + +And this is exactly +what is done here. + +And I skipped a +few equations here. + +This is what he's +done here, number one. + +And number two is, we are +interested in the system, + +not in the reservoir, +so therefore we + +perform the trace +over the reservoir. + +And the trace of the reservoir +for the photon beam splitter + +mend, we say we have +two possible states, + +we detect a photon or not. + +And for the system, we +have now a density matrix + +which is probability P naught +in one state, probability + +P1 in the other state. + +And this is exactly what the +operator partial trace does. + +Remember also I want +to really make sure + +that you recognize +all the structures. + +The time evolution of a density +matrix was a commutator with h, + +but in the interaction picture, +it's a commutator with v. + +But since we are putting the +first order result in here, + +the second order result +is now the commutator + +of v with the +commutator of v and o. + +It's just we have +iterated one more time. + +So the sigma tilde, the +density matrix for our system, + +tilde means in the +interaction picture + +is now the partial +trace over the reservoir + +of the total density matrix. + +Tilde means in the +interaction picture. + +And the important part +here is that it is exact. + +We have not done any +approximation here. + +Any questions? + +Of course, now we have to +make approximations because we + +cannot solve an interactive +problem exactly. + +The first one is-- and what +do we want to do in the end? + +We want to keep the +first non-trivial term + +but to the extent possible, we +want to factorize everything. + +We want to get rid of the +entanglement of the environment + +in the system and only get +sort of the minimum which + +is provided by the coupling. + +So this evolves as follows. + +The interaction we assume is +a product of two operators. + +One operator acts on +the system, one operator + +acts on the environment. + +So this could be the dipole +acting on the atom, the vacuum + +field, e, interacting +with the environment + +or it could be p dot a. + +Or maybe your system has +a magnetic moment, m, + +and the environment consists +of fluctuating magnetic fields. + +So we'll pretty much find +in every kind of measurement + +that a measurement involves +the product of two operators. + +One is an operator +for your system + +and one is an operator for the +reservoir of the environment. + +And so this is one +thing we want to use, + +and now there is one +thing which the moment we + +will set in our equations, +there is one thing + +which will naturally appear. + +Let me scroll back. + +What we have here is the +interaction operator, v, + +at two different times. + +So this means if something +happens at different times + +and we integrate over times. + +This is a correlation function, +a correlation function + +between v at the time t prime +and the time t double prime + +and since the reservoir +part of this interaction + +is the operator, r, so +what we have here now is, + +we have a correlation +between the operator, r, + +at two times, which +characterizes the environment. + +And now comes an +important approximation. + +You remember I said we want to +assume that the environment has + +a very short correlation time. + +Whenever a photon is emitted, +it appears dramatically fast. + +It disappears in +one optical cycle, + +and the environment +is sort of reset, + +it's back in the vacuum state. + +So this is now expressed here +that this product over which + +we take the partial trace has +a very short coherence time. + +And the fact is +now the following. + +We are integrating over a +coarse-grained step delta t, + +but this correlation function +goes to 0 in a very short time. + +So therefore it will +not contribute a lot. + +Let me write that down. + +What we are going to approximate +is our total density matrix + +is now approximately +factorizing in a density matrix + +describing the atomic system. + +Well, we describe +the atomic system + +when we trace out +the environment. + +We describe the environment when +we trace out the atomic part. + +And if we now form +the direct product, + +we are back to the +total system, but we + +have factorized the total +density matrix into two parts. + +What we neglect here is a part +which cannot be factorized + +which is the +correlated part of it. + +But what happens is, since we +are integrating over time steps + +delta t and the +correlation decay + +in a very, very short +time, the result is + +that this complicated part, +which we could never calculate, + +is smaller than the first +part by the ratio of the time + +where the correlations +contribute over the time delta + +t, the time step we +are going to take. + +So this is a very +critical assumption. + +There is a whole page +or two in the book where + +an photon-atom +interaction they discuss + +the validity of this +assumption, but I've given you + +the physical motivation that we +indicate over much larger time, + +and if this time is large +and the correlation is + +lost for short time, +they only contribute + +with this small +parameter to the result. + +So in other words, +this means after-- we + +have an interaction between +the environment and the system. + +We write it down +in second order, + +but the second +order result is now + +we evaluated by +factorizing the density + +matrix into our system +in the reservoir. + +So that means in that sense +if you factorize something, + +it looks as if it's +not interacting, + +but the trick is the same. + +You write down something +to first and second order, + +and once you have factored +out the important physics, + +now you can evaluate +the expression + +by using an approximation, +which is now the approximation + +that the density +matrix factorizes. + +So with that, this +is the approximation + +that we have made that the +correlation time is very short. + +And now we have a +differential equation + +for the density matrix +sigma, which describes + +or atomic system. + +We have traced out the +degrees of the reservoir. + +And now we want to insert B.17. + +You probably don't +remember what B.17 is. + +It says that the +interaction operator + +is a product of a, the +operator a for the atoms + +and r for the reservoir. + +So the reservoir part, tau +prime tau double prime, + +gives a correlation function. + +This is the correlation +function between the operator, + +r, at two different +times and the part + +which acts on our system, the a +part, is explicitly kept here. + +So this is now a +general master equation. + +It tells us the time +evolution of the density + +matrix in this form. + +It looks very +complicated, but this + +is because it's very general. + +In order to bring it +into an easier form, + +we want to now introduce a basis +of states, energy eigenstates + +of the unperturbed +system, and write down + +all of these operator into +such a basis of states. + +But anyway you saw here how +we had an exact equation, + +and the main +approximation we made + +is that the operator +acting on the environment + +has a very short +correlation time. + +Any questions? + +Well, you're only +a few minutes away + +from producing this result +to Fermi's golden rule, which + +you have known for +a long, long time. + +It's just we have made +very general assumptions. + +You see sort of how the +assumptions propagate, + +but now if you write it down +for an energy eigenbasis, + +you will immediately see +results you have probably + +known since your childhood. + +So we want to have +energy eigenstates + +of the atomic +operators, so this is + +sort of ground and +excited state if you + +think about a two-level system. + +The previous equation, +I have to go back to it. + +Our previous equation is +a differential equation + +for the density matrix here, +and here is the density matrix. + +So now we formulate +this equation + +into an energy eigenbasis, +and what do we get? + +Well, we get an equation +for the matrix elements, + +and what matrix +elements are important? + +diagonal matrix elements +which are population + +of diagonal matrix elements +which are coherences. + +So we pretty much +take this equation, + +use the energy +eigenbasis and look, + +what do we get for +the populations + +and what do we get +for the coherences. + +So the structure is +now the following. + +That we have our +matrix elements ab. + +There is one part which looks +like a unitary time evolution. + +This is what comes from +the Hamilton operator. + +This is sort of the-- we'll +see that in a moment-- + +but this is the time +evolution without relaxation + +and now we have +something here which + +are generalized +relaxation coefficients. + +And you will find if +you go further above + +that those relaxation +coefficients are directly + +related to the correlation +function of the reservoir. + +So we can now specify what +happens between populations. + +Population means that we +have a differential equation, + +let's say between +sigma aa the puller, + +and sigma cc, so we +have a rate coefficient + +which connects the +population in state A + +with the population in state C. + +And if you take this expression, +you find several things. + +Well, you find +Fermi's golden rule, + +in a generalized +way-- that's always + +nice-- you find +Fermi's golden rule. + +When you integrate over time, +you often get data function, + +and you expect to get a +delta function because + +of energy conservation. + +So you get that, of +course, naturally. + +Secondly, we have second +order matrix element, + +which you know from +Fermi's golden rule, + +but now we have the +following situation + +that the matrix element +in Fermi's golden rule + +may actually depend on the +state, mu, of the environment. + +So you have maybe 10 +different possibilities + +for the environment, +and Fermi's golden rule + +gives you spontaneous +emission, which + +is different for +those 10 states. + +And naturally, since we have +performed the partial trace + +over the environment, +we have all those rates + +weighted with the probability +that the environment + +is in one of those states. + +So what you find here is +a simple generalization + +of Fermi's golden rule. + +And if you look at the +off-diagonal matrix elements, + +for instance, you +want to know what + +is this rate, what is the rate +coefficient, which gives you + +the time derivative +of the coherence, + +and it's multiplied +with the coherence. + +You'll find now that in general, +this rate coefficient has + +a damping term, but it may +also have an imaginary term. + +And I hope you remember when we +played with diagrams, that we + +had something similar. + +There was something which we +called the radiative shift. + +I called it the AC stock +effect of a single photon, + +and here it is a +level shift which + +comes because the environment +interacts with your system + +and it shifts the +levels a little bit. + +So in addition to +just relaxation, + +spontaneous emission, +and damping, + +there is also a dispersive +part, a level shift, + +and it has exactly +the same structure. + +Let me add that delta +ab is the difference + +between the shift of state +b and the shift of state a. + +And those shifts have +exactly the same structure. + +You have to take the principle +part of something which + +has 1 over the +difference of energies, + +and we discussed that +this has to be understood + +by somewhere adding an +infinitesimal imaginary part + +and doing the right thing +with complex function. + +It's actually related to +Laplace time difference + +between Laplace transformation +and Fourier transformation. + +So anyway what I find +sort of beautiful + +is that we started with +a most general situation. + +We perform the partial trace. + +We made one assumption of +short correlation times, + +and a lot of things we have +known about quantum system + +just pops out in a +very general form here. + +Any questions about so far? + +Well, the coherences are, +of course, more interesting + +than the population. + +Coherence is always something +physicists get excited about it + +because it captures +something which goes often + +beyond classical +system that we have + +quantum mechanical coherences. + +And what happens is the +coefficient here, which + +provides the damping +of the coherence, + +just comes out of the +formalism, has two parts. + +And one part is +an adiabatic part + +and the other one is +a non-adiabatic part. + +Well, and that makes sense. + +If you have two quantum +states and there + +is a coherence, some +phase between the two, + +the phase can get lost if you +do a transition between the two + +states or one state undergoes +a collision and is quenched. + +So you definitely have one +part which is due to the fact + +that the quantum states +or the population + +changes, and you find that there +is this state-changing part, + +which is pretty much +the sum of all the rate + +coefficient leading +out of state, + +leading to the decay +of state a and leading + +to the decay of state b. + +In other words, if you have +a two-level system, which + +has a coherence and you +have decay of the excited + +state and decay of +the ground state, + +you would expect that those +decay terms appear also + +in the decay of the coherence +between the two levels + +and they do, and they appear +with the correct factor of 1/2. + +But there is another possibility +and this is the following. + +You can have no [INAUDIBLE] of +the population of the state, + +but you can still +lose the coherence. + +The model you +should maybe make is + +that you have spin +up, spin down. + +You are not perturbing +the populations + +in spin up and spin +down, but the environment + +provides fluctuating +magnetic field. + +Then due to the +fluctuating magnetic field, + +you no longer can keep +track of the phase, + +and that means in +your identity matrix + +the off-diagonal +matrix elements decay. + +And we find that here this +is the second part which + +in this book is called +the adiabatic part, + +and the physics behind it +is now pure de-phasing. + +So it's an independent +way for coherences + +to decay independent of the +decay of the population. + +Questions? + +Collin. + +AUDIENCE: Where does the +Markov approximation come in? + +PROFESSOR: The Markov +approximation is, so to speak, + +the delta function +approximation, + +which would say that-- I mean, +I introduced the correlation + +function between the +reservoir operator + +and said the correlation time +tau c is very, very short. + +The Markov approximation +would actually + +state that it would actually +say in a more radical way + +the correlation time is 0. + +And the Bohr +approximation, the fact + +that the reservoir +is unchanged came + +in when we said +the total density + +matrix for the second order +expression just factorizes. + +It factorizes into +the environment, + +which is just this density +matrix of the environment. + +It's not changed by the +interaction with the system. + +And this is the +Bohr approximation. + +We just use the same expression +for the reservoir independent + +of the measurements +the reservoir has done. + +Other questions? + +Yes, Nancy. + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: This is +something very general. + +Thank you actually +for the question. + +Whenever we have some +damping of the population, + +the coherence is only +damped with a factor of 1/2. + +One way to explain it +in a very simple way + +is, that if you have an +amplitude alpha excited + +and alpha ground, the +population in the excited state + +is this squared. + +So you sometimes make the +model that the amplitude decays + +with gamma over 2, +but the population + +is-- because you take the +product, decays with gamma. + +So you would say alpha +e and alpha g both decay + +with half the rate, +but the probability + +is for the total rate, +and the coherence + +is the product of +the amplitudes. + +So therefore when you +look at the coherence, + +this decays with 1/2 gamma e. + +This decays with 1/2 gamma g, +and this is what you get here, + +1/2 gamma in state a, +1/2 gamma in state b. + +Whereas the probability +to be in this state + +decays with twice that because +the probability is squared. + +So you find that pretty much +in any quantum mechanically + +corrects derivation, +which you do + +about the decay of +population coherences. + +Other questions? + +So we have done two things. + +We have done the very, +very simple derivation + +using the beam splitter +model where you may not even + +notice where I did the Markov +approximation because I jumped + +from beam splitter +to beam splitter + +and left all the +correlations behind. + +Here in the most +general calculation, + +you have seen exactly +where it enters, + +but maybe now you have the +full forest in front of you, + +and you don't recognize +the trees anymore. + +So let me wrap up this +lecture by now focusing + +on the system we want +to discuss further on, + +namely a two-level system +interacting with a vacuum + +through spontaneous emission. + +But I also want to make +some generalizations. + +I want to give you some +generalizations about what + +kind of environments are +possible in quantum physics. + +Let me just see how I do that. + +So this part I actually owe to +Professor [? Ikschuan ?] who + +wonderfully compiled that. + +So what I want to +do now is, I want + +to call your attention +to the operator + +form which, is rather unique. + +Remember when we did second +order perturbation theory, + +we had sort of the +commutator of v + +with the commutator +of v and rho. + +This came from iterating +the exact equation of motion + +for the density matrix. + +And you want to specialize that +now to Jaynes-Cummings model. + +I mean, in the end, at +least in this course, + +we always come back to +the Jaynes-Cummings model + +because it captures a lot +of what we want to explore. + +So the Jaynes-Cummings model in +the rotating wave approximation + +is very simple. + +It raises the atom from +ground to excited state + +and destroys a photon, +or it does the opposite. + +So this is our +simple interaction + +between our system, +the two-level atom + +and our reservoir which is just +the vacuum of all the modes. + +And you, again, recognize +what I said in general. + +You usually always +find it by linear form, + +an operator which +acts on the modes, + +on the reservoir on the +vacuum, and an operator which + +acts on the vacuum. + +Now, we want to make +the explicit assumption + +that the initial state of the +reservoir is the vacuum state. + +It's empty. + +And I want to show you +what is the structure + +of the operators we obtain. + +And so if you put +v into here, you + +have first the commutator with +rho, which I write down here, + +and then we have to take +another commutator with v. + +And the result of +that is the following, + +that when it comes +to relaxation pauses, + +based on the general +structure of the time + +evolution of quantum mechanics, +we have this double commutator. + +And the operator which, couples +our system to the environment + +is erasing and +lower an operator. + +I mean, the atom because it +interacts with the environment + +either absolves the photon +or emits the photon. + +But those operators, sigma +plus and sigma minus, + +appear now always as +products because we + +have two occurrences +of the interaction, + +v. But if you look at the +double commutator structure, + +the operator sigma plus +sigma minus appears. + +This is just the +general structure + +of this double +commutator appears + +to the left side of the +atomic density matrix + +to the right side of the +atomic density matrix + +and then there is the coarse +term where the atomic density + +matrix is in the +middle of the two. + +So this is actually +something which + +is very general +and very important + +in the theory of +open quantum system. + +What I'm discussing with you now +is this famous Lindblad form. + +And the story goes like that. + +You want to know what are +possible environments, not just + +empty vacuum. + +You can have fluctuating fields. + +You can have, you name it. + +But if you are saying that +your environment interacts + +with your system +through an operator, + +and our operator is now the +operator sigma minus, which + +is a spontaneous emission, +you need heavy t. + +The mathematical structure +of a valid quantum field + +remains that if your system +interacts with an environment + +by emitting a +photon sigma minus, + +this is now the structure +of the master equation. + +This is the structure of the +time evolution of the density + +matrix. + +So the operator +sigma minus and its + +and its Hermitian conjugate +sigma plus, all of this + +have to appear in +this combination. + +Yes, Collin. + +AUDIENCE: This is still +in my interaction picture. + +Right? + +There's no dynamical +phase evolution + +that we put back in there. + +PROFESSOR: Yeah. + +OK. + +What we do in general if the +system is driven by a laser + +beam, for instance, +Rabi oscillation, + +we simply add up the dynamics +of the Rabi oscillation + +of the unitary time evolution +to the time evolution + +done by the reservoir. + +AUDIENCE: So this form is always +in the interaction picture? + +PROFESSOR: Well, this +is, you would say, + +this form is what is +the relaxation provided + +by the environment. + +And if you drive the +system in addition + +with the coherent field, +unitary time evolution, + +you would add it to it. + +So in other words, +what I'm telling + +you here is that this is +the general structure, + +and if you have a +system which interacts + +with an environment in +five different ways, + +with a dipole wand, with a +magnetic moment and such, + +you have maybe five +interaction terms + +and then you have to perform +the sum over five operators, + +and here one of them is +a sigma minus operator. + +So in other words, +if you want to know + +what is the whole world of +possibilities for quantum + +system to relax and dissipate +with an environment, + +you can pretty much +take any operator which + +acts on your system, +but then put it + +into this so-called +Lindblad form + +and you have a +possible environment. + +And I mentioned +I think last week + +that people are now in +our field actively working + +on environmental engineering. + +They want to expose a system +to an artificial environment + +and hope the system is +not relaxing, let's say, + +to a broken ground state, but +to a fancy correlated state. + +So what this Lindblad form, +if the operators appears + +in this way, what it +insures is the following. + +Just imagine if we +have an equation, + +a derivative of +the density matrix, + +which depends on +the density matrix, + +you could write down a +differential equation and say + +is it possible? + +Well, it has to be consistent +with quantum physics. + +You have certain requirements. + +One requirement is that +rho, the density matrix, + +always has to be +the density matrix. + +The trace equal 1 +has to be conserved. + +A density matrix always must +have non-negative eigenvalues, + +otherwise, what +you write down, it + +might be a nice differential +equation, but quantum + +mechanically, it's nonsense. + +But now there is one more +thing, which is also necessary. + +This time evolution of the +system's density matrix + +must come from a unitary time +evolution of a bigger system. + +So you must be able to extend +your system into a bigger + +system, which is +now the environment, + +and this whole system must +follow a Schrodinger equation + +with a Hamilton as a +unitary time evolution. + +And this is where +it's restrictive. + +You cannot just write down a +differential equation and hope + +that this will fill +some requirement, + +and what people have shown is +under very general assumptions, + +it is the Lindblad form +which allows for it. + +So some operator always +has to appear in this form. + +So often in this +Lindblad form, you + +have an operator, which is +called a jump operator, which + +is responsible for +the measurement, which + +the environment +does on your system. + +The jump operator is +here, the operator + +which takes the atom from the +excited to the ground state. + +With that you need a photon, +and the photon can be measured. + +So often you can describe a +system by a jump operator, + +and if the jump operator is +put into this Lindblad form, + +then you have a valid master +equation for your system. + +So let me wrap up. + +If you take now the definition +of the raising and lowering + +operator, and you take the +form I showed you, the Lindblad + +form, you'll find now +this differential equation + +for your two-level system. + +And this is one part of +the Optical Bloch Equation. + +Now, coming to +Collin's question, + +if you include +the time evolution + +of the classical field, +this is a coherent evolution + +of the Bloch vector, +which I showed + +at the beginning of +the class, and we + +add this and what I wrote down +at the beginning of the class. + +Then we find the famous +Optical Bloch Equations + +in the Jaynes-Cummings model. + +So these are now the +Optical Bloch Equations, + +and I hope you enjoy now after +this complicated discussion, + +how simple they are. + +And it is this simple +set of equations, + +which will be used in +the rest of the course + +to describe the time +evolution of the system. + +Just because I did +some generalizations + +about the Lindblad equation, +I copied that into the lecture + +notes from Wikipedia, +and probably now you + +sort of understand what is the +most general Lindblad equation. + +It has a Hamiltonian +part and then it + +has jump operators like +you sigma minus operator, + +but it has to come in +the form that the jump + +operator and its complex +conjugate, emission. conjugate, + +is on the left side, on the +right side, and left and right + +of your density matrix. + +So this is the generalization +I've mentioned. + +Yeah. with that I think with +that we've derived the master + +equation, and on +Wednesday, we will + +look at rather simple solutions, +transient and steady-state + +solution of the +Optical Bloch Equation. + +Any questions? + +One reminder about the +schedule, this week + +we have a lecture on +Friday because I will not + +be on town next +week on Wednesday. + +And of course, you know today +in a week, next week on Monday. + +It's [INAUDIBLE] day. + +So we have three +classes this week, + +no class the following week, +and then the normal schedule + +for the rest of the semester. \ No newline at end of file diff --git a/RUjePzTQfQg.txt b/RUjePzTQfQg.txt new file mode 100644 index 0000000000000000000000000000000000000000..0ac660e284af2bd57c3004a019ea957c82412e06 --- /dev/null +++ b/RUjePzTQfQg.txt @@ -0,0 +1,7683 @@ +align:start position:0% + +the following content is provided by MIT + + align:start position:0% +the following content is provided by MIT + + + align:start position:0% +the following content is provided by MIT +open courseware under a Creative Commons + + align:start position:0% +open courseware under a Creative Commons + + + align:start position:0% +open courseware under a Creative Commons +license additional information about our + + align:start position:0% +license additional information about our + + + align:start position:0% +license additional information about our +license and MIT open courseware in + + align:start position:0% +license and MIT open courseware in + + + align:start position:0% +license and MIT open courseware in +general is available at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu all right today uh we're + + align:start position:0% +ocw.mit.edu all right today uh we're + + + align:start position:0% +ocw.mit.edu all right today uh we're +going to start on a topic that's one of + + align:start position:0% +going to start on a topic that's one of + + + align:start position:0% +going to start on a topic that's one of +the harder topics that we cover this + + align:start position:0% +the harder topics that we cover this + + + align:start position:0% +the harder topics that we cover this +semester we going to start talking about + + align:start position:0% +semester we going to start talking about + + + align:start position:0% +semester we going to start talking about +um molecular orbital Theory + + align:start position:0% +um molecular orbital Theory + + + align:start position:0% +um molecular orbital Theory +so this is a quantum mechanical + + align:start position:0% +so this is a quantum mechanical + + + align:start position:0% +so this is a quantum mechanical +description of the wave functions in a + + align:start position:0% +description of the wave functions in a + + + align:start position:0% +description of the wave functions in a +molecule and we're going to use + + align:start position:0% +molecule and we're going to use + + + align:start position:0% +molecule and we're going to use +molecular orbital Theory to uh look at + + align:start position:0% +molecular orbital Theory to uh look at + + + align:start position:0% +molecular orbital Theory to uh look at +the + + align:start position:0% +the + + + align:start position:0% +the +bonding in datomic molecules that's what + + align:start position:0% +bonding in datomic molecules that's what + + + align:start position:0% +bonding in datomic molecules that's what +we'll do for the rest of today we'll + + align:start position:0% +we'll do for the rest of today we'll + + + align:start position:0% +we'll do for the rest of today we'll +look solely at diatomic + + align:start position:0% +look solely at diatomic + + + align:start position:0% +look solely at diatomic +molecules and we'll look mostly at + + align:start position:0% +molecules and we'll look mostly at + + + align:start position:0% +molecules and we'll look mostly at +homonuclear diatomic molecules at the + + align:start position:0% +homonuclear diatomic molecules at the + + + align:start position:0% +homonuclear diatomic molecules at the +end we'll look at one heteronuclear + + align:start position:0% +end we'll look at one heteronuclear + + + align:start position:0% +end we'll look at one heteronuclear +datomic + + align:start position:0% +datomic + + + align:start position:0% +datomic +molecule and then on um and then on + + align:start position:0% +molecule and then on um and then on + + + align:start position:0% +molecule and then on um and then on +Monday we're actually going to use a + + align:start position:0% +Monday we're actually going to use a + + + align:start position:0% +Monday we're actually going to use a +different kind of approach to look at + + align:start position:0% +different kind of approach to look at + + + align:start position:0% +different kind of approach to look at +the chemical bonding in molecules that + + align:start position:0% +the chemical bonding in molecules that + + + align:start position:0% +the chemical bonding in molecules that +are larger than datomic all right so + + align:start position:0% +are larger than datomic all right so + + + align:start position:0% +are larger than datomic all right so +we're going to use molecular orbital + + align:start position:0% +we're going to use molecular orbital + + + align:start position:0% +we're going to use molecular orbital +theory for these diatomic + + align:start position:0% +theory for these diatomic + + + align:start position:0% +theory for these diatomic +molecules and then on Monday we'll go a + + align:start position:0% +molecules and then on Monday we'll go a + + + align:start position:0% +molecules and then on Monday we'll go a +little bit further we'll look at big ger + + align:start position:0% +little bit further we'll look at big ger + + + align:start position:0% +little bit further we'll look at big ger +molecules and we're going to use + + align:start position:0% +molecules and we're going to use + + + align:start position:0% +molecules and we're going to use +something else we're going to use veence + + align:start position:0% +something else we're going to use veence + + + align:start position:0% +something else we're going to use veence +Bond Theory and hybridization ideas all + + align:start position:0% +Bond Theory and hybridization ideas all + + + align:start position:0% +Bond Theory and hybridization ideas all +right but today we're going to deal with + + align:start position:0% +right but today we're going to deal with + + + align:start position:0% +right but today we're going to deal with +these datomic molecules the molecular + + align:start position:0% +these datomic molecules the molecular + + + align:start position:0% +these datomic molecules the molecular +orbital approach all right so here + + align:start position:0% +orbital approach all right so here + + + align:start position:0% +orbital approach all right so here +goes we're going to start talking about + + align:start position:0% +goes we're going to start talking about + + + align:start position:0% +goes we're going to start talking about +hydrogen as we usually do when we start + + align:start position:0% +hydrogen as we usually do when we start + + + align:start position:0% +hydrogen as we usually do when we start +talking about chemical + + align:start position:0% +talking about chemical + + + align:start position:0% +talking about chemical +bonding so I'm going to represent my + + align:start position:0% +bonding so I'm going to represent my + + + align:start position:0% +bonding so I'm going to represent my +hydrogen atom here by this nucleus here + + align:start position:0% +hydrogen atom here by this nucleus here + + + align:start position:0% +hydrogen atom here by this nucleus here +a this is is going to be hydrogen atom a + + align:start position:0% +a this is is going to be hydrogen atom a + + + align:start position:0% +a this is is going to be hydrogen atom a +and I'm going to represent the wave + + align:start position:0% +and I'm going to represent the wave + + + align:start position:0% +and I'm going to represent the wave +function of that hydrogen atom by a + + align:start position:0% +function of that hydrogen atom by a + + + align:start position:0% +function of that hydrogen atom by a +circle right because after all the 1 s + + align:start position:0% +circle right because after all the 1 s + + + align:start position:0% +circle right because after all the 1 s +wave function in hydrogen is spherically + + align:start position:0% +wave function in hydrogen is spherically + + + align:start position:0% +wave function in hydrogen is spherically +symmetric so I'm going to represented by + + align:start position:0% +symmetric so I'm going to represented by + + + align:start position:0% +symmetric so I'm going to represented by +a circle around the nucleus so this is + + align:start position:0% +a circle around the nucleus so this is + + + align:start position:0% +a circle around the nucleus so this is +going to be + + align:start position:0% +going to be + + + align:start position:0% +going to be +1s and then I'm going to of course have + + align:start position:0% +1s and then I'm going to of course have + + + align:start position:0% +1s and then I'm going to of course have +a second hydrogen atom represented here + + align:start position:0% +a second hydrogen atom represented here + + + align:start position:0% +a second hydrogen atom represented here +by this nucleus b in a circle around it + + align:start position:0% +by this nucleus b in a circle around it + + + align:start position:0% +by this nucleus b in a circle around it +because that wave function is + + align:start position:0% +because that wave function is + + + align:start position:0% +because that wave function is +spherically + + align:start position:0% +spherically + + + align:start position:0% +spherically +symmetric and what I'm going to do in + + align:start position:0% +symmetric and what I'm going to do in + + + align:start position:0% +symmetric and what I'm going to do in +this molecular orbital Theory approach + + align:start position:0% +this molecular orbital Theory approach + + + align:start position:0% +this molecular orbital Theory approach +is that I'm going to take these two wave + + align:start position:0% +is that I'm going to take these two wave + + + align:start position:0% +is that I'm going to take these two wave +functions and I'm going to bring them a + + align:start position:0% +functions and I'm going to bring them a + + + align:start position:0% +functions and I'm going to bring them a +distance of the bond length apart so in + + align:start position:0% +distance of the bond length apart so in + + + align:start position:0% +distance of the bond length apart so in +other words I'm going to take those two + + align:start position:0% +other words I'm going to take those two + + + align:start position:0% +other words I'm going to take those two +hydrogen atoms and I'm going to put the + + align:start position:0% +hydrogen atoms and I'm going to put the + + + align:start position:0% +hydrogen atoms and I'm going to put the +two nuclei here a A and + + align:start position:0% +two nuclei here a A and + + + align:start position:0% +two nuclei here a A and +B at a distance of a bond length apart + + align:start position:0% +B at a distance of a bond length apart + + + align:start position:0% +B at a distance of a bond length apart +and I'm going to let these two wave + + align:start position:0% +and I'm going to let these two wave + + + align:start position:0% +and I'm going to let these two wave +functions + + align:start position:0% +functions + + + align:start position:0% +functions +overlap right and these are wave + + align:start position:0% +overlap right and these are wave + + + align:start position:0% +overlap right and these are wave +functions and what we learned a few + + align:start position:0% +functions and what we learned a few + + + align:start position:0% +functions and what we learned a few +weeks ago is that waves constructively + + align:start position:0% +weeks ago is that waves constructively + + + align:start position:0% +weeks ago is that waves constructively +interfere or destructively interfere + + align:start position:0% +interfere or destructively interfere + + + align:start position:0% +interfere or destructively interfere +what we're going to do first here is + + align:start position:0% +what we're going to do first here is + + + align:start position:0% +what we're going to do first here is +we're going to let these two waves + + align:start position:0% +we're going to let these two waves + + + align:start position:0% +we're going to let these two waves +constructively interfere where they + + align:start position:0% +constructively interfere where they + + + align:start position:0% +constructively interfere where they +overlap all right so when we do that + + align:start position:0% +overlap all right so when we do that + + + align:start position:0% +overlap all right so when we do that +this part of the wave function here is + + align:start position:0% +this part of the wave function here is + + + align:start position:0% +this part of the wave function here is +going to constructively interfere with + + align:start position:0% +going to constructively interfere with + + + align:start position:0% +going to constructively interfere with +this part of this wave + + align:start position:0% +this part of this wave + + + align:start position:0% +this part of this wave +function and then the sum of those two + + align:start position:0% +function and then the sum of those two + + + align:start position:0% +function and then the sum of those two +is going to look something like this + + align:start position:0% +is going to look something like this + + + align:start position:0% +is going to look something like this +right where now there's this + + align:start position:0% +right where now there's this + + + align:start position:0% +right where now there's this +constructive interference between these + + align:start position:0% +constructive interference between these + + + align:start position:0% +constructive interference between these +two + + align:start position:0% +two + + + align:start position:0% +two +nuclei right there's a lot of wave + + align:start position:0% +nuclei right there's a lot of wave + + + align:start position:0% +nuclei right there's a lot of wave +function right here because we + + align:start position:0% +function right here because we + + + align:start position:0% +function right here because we +superimposed those two wave functions + + align:start position:0% +superimposed those two wave functions + + + align:start position:0% +superimposed those two wave functions +each from one hydrogen atom and so + + align:start position:0% +each from one hydrogen atom and so + + + align:start position:0% +each from one hydrogen atom and so +there's constructive interference here + + align:start position:0% +there's constructive interference here + + + align:start position:0% +there's constructive interference here +there's a lot of wave function right + + align:start position:0% +there's a lot of wave function right + + + align:start position:0% +there's a lot of wave function right +there and in so doing what we're going + + align:start position:0% +there and in so doing what we're going + + + align:start position:0% +there and in so doing what we're going +to call this resultant wave function + + align:start position:0% +to call this resultant wave function + + + align:start position:0% +to call this resultant wave function +here we're going to call that the + + align:start position:0% +here we're going to call that the + + + align:start position:0% +here we're going to call that the +molecular wave function or the molecular + + align:start position:0% +molecular wave function or the molecular + + + align:start position:0% +molecular wave function or the molecular +orbital + + align:start position:0% + + + + align:start position:0% + +right and how we got it was simply a + + align:start position:0% +right and how we got it was simply a + + + align:start position:0% +right and how we got it was simply a +linear combination of atomic orbitals + + align:start position:0% +linear combination of atomic orbitals + + + align:start position:0% +linear combination of atomic orbitals +right this is a linear combination of + + align:start position:0% +right this is a linear combination of + + + align:start position:0% +right this is a linear combination of +atomic + + align:start position:0% + + + + align:start position:0% + +orbitals we just brought those two atoms + + align:start position:0% +orbitals we just brought those two atoms + + + align:start position:0% +orbitals we just brought those two atoms +close enough so that their wave + + align:start position:0% +close enough so that their wave + + + align:start position:0% +close enough so that their wave +functions + + align:start position:0% +functions + + + align:start position:0% +functions +overlapped constructive interference and + + align:start position:0% +overlapped constructive interference and + + + align:start position:0% +overlapped constructive interference and +the result is a molecular wave + + align:start position:0% +the result is a molecular wave + + + align:start position:0% +the result is a molecular wave +function now we're going to give that + + align:start position:0% +function now we're going to give that + + + align:start position:0% +function now we're going to give that +molecular wave function a name we're + + align:start position:0% +molecular wave function a name we're + + + align:start position:0% +molecular wave function a name we're +going to call it a sigma wave function + + align:start position:0% +going to call it a sigma wave function + + + align:start position:0% +going to call it a sigma wave function +the sigma designates the symmetry of + + align:start position:0% +the sigma designates the symmetry of + + + align:start position:0% +the sigma designates the symmetry of +that wave function with respect to the + + align:start position:0% +that wave function with respect to the + + + align:start position:0% +that wave function with respect to the +bond axis this is the bond axis right + + align:start position:0% +bond axis this is the bond axis right + + + align:start position:0% +bond axis this is the bond axis right +here the sigma represents the fact that + + align:start position:0% +here the sigma represents the fact that + + + align:start position:0% +here the sigma represents the fact that +this is cylindrically symmetric about + + align:start position:0% +this is cylindrically symmetric about + + + align:start position:0% +this is cylindrically symmetric about +the molecular Bond axis that's what that + + align:start position:0% +the molecular Bond axis that's what that + + + align:start position:0% +the molecular Bond axis that's what that +Sigma means and we're going to call this + + align:start position:0% +Sigma means and we're going to call this + + + align:start position:0% +Sigma means and we're going to call this +a sigma 1s orbital it's a sigma 1s + + align:start position:0% +a sigma 1s orbital it's a sigma 1s + + + align:start position:0% +a sigma 1s orbital it's a sigma 1s +orbital because this was a linear + + align:start position:0% +orbital because this was a linear + + + align:start position:0% +orbital because this was a linear +combination of two 1s Atomic + + align:start position:0% +combination of two 1s Atomic + + + align:start position:0% +combination of two 1s Atomic +orbitals + + align:start position:0% +orbitals + + + align:start position:0% +orbitals +okay all right but now what I want to do + + align:start position:0% +okay all right but now what I want to do + + + align:start position:0% +okay all right but now what I want to do +is I want to remind you that the + + align:start position:0% +is I want to remind you that the + + + align:start position:0% +is I want to remind you that the +physically significant part of this wave + + align:start position:0% +physically significant part of this wave + + + align:start position:0% +physically significant part of this wave +function was actually the wave function + + align:start position:0% +function was actually the wave function + + + align:start position:0% +function was actually the wave function +Square squared remember that we talked + + align:start position:0% +Square squared remember that we talked + + + align:start position:0% +Square squared remember that we talked +about taking the wave function squaring + + align:start position:0% +about taking the wave function squaring + + + align:start position:0% +about taking the wave function squaring +it and that interpretation is a + + align:start position:0% +it and that interpretation is a + + + align:start position:0% +it and that interpretation is a +probability density that was what was + + align:start position:0% +probability density that was what was + + + align:start position:0% +probability density that was what was +critical to our understanding of where + + align:start position:0% +critical to our understanding of where + + + align:start position:0% +critical to our understanding of where +the electrons are in a molecule so + + align:start position:0% +the electrons are in a molecule so + + + align:start position:0% +the electrons are in a molecule so +that's what we're going to do here we're + + align:start position:0% +that's what we're going to do here we're + + + align:start position:0% +that's what we're going to do here we're +going to take this Sigma 1s molecular + + align:start position:0% +going to take this Sigma 1s molecular + + + align:start position:0% +going to take this Sigma 1s molecular +wave function + + align:start position:0% +wave function + + + align:start position:0% +wave function +now and we're going to square it and + + align:start position:0% +now and we're going to square it and + + + align:start position:0% +now and we're going to square it and +that's then proportional to or + + align:start position:0% +that's then proportional to or + + + align:start position:0% +that's then proportional to or +interpreted as a probability density + + align:start position:0% +interpreted as a probability density + + + align:start position:0% +interpreted as a probability density +I'll just abbreviate that by P but this + + align:start position:0% +I'll just abbreviate that by P but this + + + align:start position:0% +I'll just abbreviate that by P but this +is a probability density remember not a + + align:start position:0% +is a probability density remember not a + + + align:start position:0% +is a probability density remember not a +probability all + + align:start position:0% +probability all + + + align:start position:0% +probability all +right okay well if that's the case then + + align:start position:0% +right okay well if that's the case then + + + align:start position:0% +right okay well if that's the case then +I can multiply this out right because + + align:start position:0% +I can multiply this out right because + + + align:start position:0% +I can multiply this out right because +Sigma 1 s right here that Sigma 1 s + + align:start position:0% +Sigma 1 s right here that Sigma 1 s + + + align:start position:0% +Sigma 1 s right here that Sigma 1 s +is really equal to this linear + + align:start position:0% +is really equal to this linear + + + align:start position:0% +is really equal to this linear +combination of 1sa 1sb that's Sigma + + align:start position:0% +combination of 1sa 1sb that's Sigma + + + align:start position:0% +combination of 1sa 1sb that's Sigma +1s so let me take 1sa + 1 + + align:start position:0% +1s so let me take 1sa + 1 + + + align:start position:0% +1s so let me take 1sa + 1 +SB multiply it by + + align:start position:0% +SB multiply it by + + + align:start position:0% +SB multiply it by +1sa plus + + align:start position:0% +1sa plus + + + align:start position:0% +1sa plus +1sb all right that's what Sigma 1s is + + align:start position:0% +1sb all right that's what Sigma 1s is + + + align:start position:0% +1sb all right that's what Sigma 1s is +I'm just going to multiply this out and + + align:start position:0% +I'm just going to multiply this out and + + + align:start position:0% +I'm just going to multiply this out and +when I do that I'm going to get + + align:start position:0% +when I do that I'm going to get + + + align:start position:0% +when I do that I'm going to get +1sa SAR plus 1 1 SB 2 + 2 * 1s a 1 + + align:start position:0% +1sa SAR plus 1 1 SB 2 + 2 * 1s a 1 + + + align:start position:0% +1sa SAR plus 1 1 SB 2 + 2 * 1s a 1 +SB right that's my probability + + align:start position:0% +SB right that's my probability + + + align:start position:0% +SB right that's my probability +density now to make this a little bit + + align:start position:0% +density now to make this a little bit + + + align:start position:0% +density now to make this a little bit +more real for you let's plot it so I'm + + align:start position:0% +more real for you let's plot it so I'm + + + align:start position:0% +more real for you let's plot it so I'm +going to plot the probability + + align:start position:0% +going to plot the probability + + + align:start position:0% +going to plot the probability +density as a function of the position + + align:start position:0% +density as a function of the position + + + align:start position:0% +density as a function of the position +along the bond axis so in this case + + align:start position:0% +along the bond axis so in this case + + + align:start position:0% +along the bond axis so in this case +here the uh nucleus a is here + + align:start position:0% +here the uh nucleus a is here + + + align:start position:0% +here the uh nucleus a is here +and the nucleus B is there all right so + + align:start position:0% +and the nucleus B is there all right so + + + align:start position:0% +and the nucleus B is there all right so +we have a molecule now I'm just going to + + align:start position:0% +we have a molecule now I'm just going to + + + align:start position:0% +we have a molecule now I'm just going to +plot the probability density as a + + align:start position:0% +plot the probability density as a + + + align:start position:0% +plot the probability density as a +function of the position along the + + align:start position:0% +function of the position along the + + + align:start position:0% +function of the position along the +internuclear axis and what's it going to + + align:start position:0% +internuclear axis and what's it going to + + + align:start position:0% +internuclear axis and what's it going to +look like well it's going to look like + + align:start position:0% +look like well it's going to look like + + + align:start position:0% +look like well it's going to look like +this going to look something like that + + align:start position:0% +this going to look something like that + + + align:start position:0% +this going to look something like that +all right where the probability density + + align:start position:0% +all right where the probability density + + + align:start position:0% +all right where the probability density +is the highest right at nucleus a and + + align:start position:0% +is the highest right at nucleus a and + + + align:start position:0% +is the highest right at nucleus a and +the probability density is the highest + + align:start position:0% +the probability density is the highest + + + align:start position:0% +the probability density is the highest +right at nucleus B cuz Hey after all you + + align:start position:0% +right at nucleus B cuz Hey after all you + + + align:start position:0% +right at nucleus B cuz Hey after all you +know the wave function any wave function + + align:start position:0% +know the wave function any wave function + + + align:start position:0% +know the wave function any wave function +a w s wave function the highest value of + + align:start position:0% +a w s wave function the highest value of + + + align:start position:0% +a w s wave function the highest value of +that wave function is right at R is + + align:start position:0% +that wave function is right at R is + + + align:start position:0% +that wave function is right at R is +equal to zero or right at the nucleus + + align:start position:0% +equal to zero or right at the nucleus + + + align:start position:0% +equal to zero or right at the nucleus +all right so that's what that + + align:start position:0% +all right so that's what that + + + align:start position:0% +all right so that's what that +probability density looks like and I've + + align:start position:0% +probability density looks like and I've + + + align:start position:0% +probability density looks like and I've +just uh been informed here that the + + align:start position:0% +just uh been informed here that the + + + align:start position:0% +just uh been informed here that the +xeroxing on that particular figure + + align:start position:0% +xeroxing on that particular figure + + + align:start position:0% +xeroxing on that particular figure +didn't uh turn out so well all right but + + align:start position:0% +didn't uh turn out so well all right but + + + align:start position:0% +didn't uh turn out so well all right but +that's uh what it should read if you + + align:start position:0% +that's uh what it should read if you + + + align:start position:0% +that's uh what it should read if you +can't read it very + + align:start position:0% +can't read it very + + + align:start position:0% +can't read it very +well all right but the reason I PLO this + + align:start position:0% +well all right but the reason I PLO this + + + align:start position:0% +well all right but the reason I PLO this +here is to contrast it with the + + align:start position:0% +here is to contrast it with the + + + align:start position:0% +here is to contrast it with the +following suppose I take just one + + align:start position:0% +following suppose I take just one + + + align:start position:0% +following suppose I take just one +hydrogen atom and the other hydrogen + + align:start position:0% +hydrogen atom and the other hydrogen + + + align:start position:0% +hydrogen atom and the other hydrogen +atom but I take those wave functions and + + align:start position:0% +atom but I take those wave functions and + + + align:start position:0% +atom but I take those wave functions and +I just Square them and then I add them + + align:start position:0% +I just Square them and then I add them + + + align:start position:0% +I just Square them and then I add them +up all right so suppose I take a + + align:start position:0% +up all right so suppose I take a + + + align:start position:0% +up all right so suppose I take a +hydrogen atom with its wave function 1sa + + align:start position:0% +hydrogen atom with its wave function 1sa + + + align:start position:0% +hydrogen atom with its wave function 1sa +I Square + + align:start position:0% +I Square + + + align:start position:0% +I Square +it and then I take another wave function + + align:start position:0% +it and then I take another wave function + + + align:start position:0% +it and then I take another wave function +for another hydrogen atom 1sb I Square + + align:start position:0% +for another hydrogen atom 1sb I Square + + + align:start position:0% +for another hydrogen atom 1sb I Square +it and I add those two up in this case + + align:start position:0% +it and I add those two up in this case + + + align:start position:0% +it and I add those two up in this case +what that's doing is taking two hydrogen + + align:start position:0% +what that's doing is taking two hydrogen + + + align:start position:0% +what that's doing is taking two hydrogen +atoms and just taking their wave + + align:start position:0% +atoms and just taking their wave + + + align:start position:0% +atoms and just taking their wave +function and squaring them in this + + align:start position:0% +function and squaring them in this + + + align:start position:0% +function and squaring them in this +particular case what I haven't done is I + + align:start position:0% +particular case what I haven't done is I + + + align:start position:0% +particular case what I haven't done is I +haven't allowed any interference to + + align:start position:0% +haven't allowed any interference to + + + align:start position:0% +haven't allowed any interference to +happen I haven't allowed the wave + + align:start position:0% +happen I haven't allowed the wave + + + align:start position:0% +happen I haven't allowed the wave +functions to constructively interfere + + align:start position:0% +functions to constructively interfere + + + align:start position:0% +functions to constructively interfere +right I didn't add up these wave + + align:start position:0% +right I didn't add up these wave + + + align:start position:0% +right I didn't add up these wave +functions first before I squared them I + + align:start position:0% +functions first before I squared them I + + + align:start position:0% +functions first before I squared them I +squared them and then I added them up + + align:start position:0% +squared them and then I added them up + + + align:start position:0% +squared them and then I added them up +that's different than taking those wave + + align:start position:0% +that's different than taking those wave + + + align:start position:0% +that's different than taking those wave +functions letting them constructively + + align:start position:0% +functions letting them constructively + + + align:start position:0% +functions letting them constructively +interfere and then squaring + + align:start position:0% +interfere and then squaring + + + align:start position:0% +interfere and then squaring +them and you can see the difference is + + align:start position:0% +them and you can see the difference is + + + align:start position:0% +them and you can see the difference is +when I plot this sum and compare it to + + align:start position:0% +when I plot this sum and compare it to + + + align:start position:0% +when I plot this sum and compare it to +that sum right so I'm going to plot now + + align:start position:0% +that sum right so I'm going to plot now + + + align:start position:0% +that sum right so I'm going to plot now +this + + align:start position:0% +this + + + align:start position:0% +this +sum when I do that it's going to look + + align:start position:0% +sum when I do that it's going to look + + + align:start position:0% +sum when I do that it's going to look +well it's going to look pretty much like + + align:start position:0% +well it's going to look pretty much like + + + align:start position:0% +well it's going to look pretty much like +this but then right at the center right + + align:start position:0% +this but then right at the center right + + + align:start position:0% +this but then right at the center right +here hey the probability + + align:start position:0% +here hey the probability + + + align:start position:0% +here hey the probability +density right for this case for two + + align:start position:0% +density right for this case for two + + + align:start position:0% +density right for this case for two +hydrogen atoms which are now nonbonded + + align:start position:0% +hydrogen atoms which are now nonbonded + + + align:start position:0% +hydrogen atoms which are now nonbonded +they're non-bonded because I didn't let + + align:start position:0% +they're non-bonded because I didn't let + + + align:start position:0% +they're non-bonded because I didn't let +those two wave functions constructively + + align:start position:0% +those two wave functions constructively + + + align:start position:0% +those two wave functions constructively +interfere the result is that this + + align:start position:0% +interfere the result is that this + + + align:start position:0% +interfere the result is that this +probability density right in the center + + align:start position:0% +probability density right in the center + + + align:start position:0% +probability density right in the center +here hey that probability density is + + align:start position:0% +here hey that probability density is + + + align:start position:0% +here hey that probability density is +less than what it would be if I let + + align:start position:0% +less than what it would be if I let + + + align:start position:0% +less than what it would be if I let +those two hydrogen atom wave functions + + align:start position:0% +those two hydrogen atom wave functions + + + align:start position:0% +those two hydrogen atom wave functions +constructively + + align:start position:0% +constructively + + + align:start position:0% +constructively +interfere and that's the key in this + + align:start position:0% +interfere and that's the key in this + + + align:start position:0% +interfere and that's the key in this +chemical bond is this term right here + + align:start position:0% +chemical bond is this term right here + + + align:start position:0% +chemical bond is this term right here +it's this term that makes all of the + + align:start position:0% +it's this term that makes all of the + + + align:start position:0% +it's this term that makes all of the +difference this is our constructive + + align:start position:0% +difference this is our constructive + + + align:start position:0% +difference this is our constructive +interference this is the extra + + align:start position:0% +interference this is the extra + + + align:start position:0% +interference this is the extra +density that we get because those two + + align:start position:0% +density that we get because those two + + + align:start position:0% +density that we get because those two +wave functions have constructively + + align:start position:0% +wave functions have constructively + + + align:start position:0% +wave functions have constructively +interfered that's what gives me this + + align:start position:0% +interfered that's what gives me this + + + align:start position:0% +interfered that's what gives me this +pile up of elect electron density right + + align:start position:0% +pile up of elect electron density right + + + align:start position:0% +pile up of elect electron density right +in the center here this is the glue in + + align:start position:0% +in the center here this is the glue in + + + align:start position:0% +in the center here this is the glue in +this chemical bond okay make sense + + align:start position:0% + + + + align:start position:0% + +okay all + + align:start position:0% +okay all + + + align:start position:0% +okay all +right + + align:start position:0% +right + + + align:start position:0% +right +okay so we have formed now a molecular + + align:start position:0% +okay so we have formed now a molecular + + + align:start position:0% +okay so we have formed now a molecular +wave function by this linear combination + + align:start position:0% +wave function by this linear combination + + + align:start position:0% +wave function by this linear combination +of atomic wave + + align:start position:0% +of atomic wave + + + align:start position:0% +of atomic wave +functions now what happens to the energy + + align:start position:0% +functions now what happens to the energy + + + align:start position:0% +functions now what happens to the energy +when we do + + align:start position:0% +when we do + + + align:start position:0% +when we do +that well you can imagine what happens + + align:start position:0% +that well you can imagine what happens + + + align:start position:0% +that well you can imagine what happens +to the energy the energy goes down we're + + align:start position:0% +to the energy the energy goes down we're + + + align:start position:0% +to the energy the energy goes down we're +going to form a new molecular state so + + align:start position:0% +going to form a new molecular state so + + + align:start position:0% +going to form a new molecular state so +let's draw energy level diagram all + + align:start position:0% +let's draw energy level diagram all + + + align:start position:0% +let's draw energy level diagram all +right so energy going up + + align:start position:0% +right so energy going up + + + align:start position:0% +right so energy going up +here and let me represent here by these + + align:start position:0% +here and let me represent here by these + + + align:start position:0% +here and let me represent here by these +two lines the energy + + align:start position:0% +two lines the energy + + + align:start position:0% +two lines the energy +levels of the separated hydrogen atoms + + align:start position:0% +levels of the separated hydrogen atoms + + + align:start position:0% +levels of the separated hydrogen atoms +so I'm going to call this the 1s State + + align:start position:0% +so I'm going to call this the 1s State + + + align:start position:0% +so I'm going to call this the 1s State +on atom a the 1s State on atom B hey + + align:start position:0% +on atom a the 1s State on atom B hey + + + align:start position:0% +on atom a the 1s State on atom B hey +they're at the same energy they're two + + align:start position:0% +they're at the same energy they're two + + + align:start position:0% +they're at the same energy they're two +hydrogen atoms you can't P them + + align:start position:0% +hydrogen atoms you can't P them + + + align:start position:0% +hydrogen atoms you can't P them +apart and each one of them has an + + align:start position:0% +apart and each one of them has an + + + align:start position:0% +apart and each one of them has an +electron + + align:start position:0% +electron + + + align:start position:0% +electron +once we allow those two wave functions + + align:start position:0% +once we allow those two wave functions + + + align:start position:0% +once we allow those two wave functions +to constructively interfere we're going + + align:start position:0% +to constructively interfere we're going + + + align:start position:0% +to constructively interfere we're going +to produce a new state we're going to + + align:start position:0% +to produce a new state we're going to + + + align:start position:0% +to produce a new state we're going to +call that state Sigma 1s and that state + + align:start position:0% +call that state Sigma 1s and that state + + + align:start position:0% +call that state Sigma 1s and that state +is going to be lower in energy + + align:start position:0% +is going to be lower in energy + + + align:start position:0% +is going to be lower in energy +here + + align:start position:0% +here + + + align:start position:0% +here +than the two states from the individual + + align:start position:0% +than the two states from the individual + + + align:start position:0% +than the two states from the individual +hydrogen atoms and that's good because + + align:start position:0% +hydrogen atoms and that's good because + + + align:start position:0% +hydrogen atoms and that's good because +if it's lower in energy hey we got these + + align:start position:0% +if it's lower in energy hey we got these + + + align:start position:0% +if it's lower in energy hey we got these +two hydrogen atoms stuck together right + + align:start position:0% +two hydrogen atoms stuck together right + + + align:start position:0% +two hydrogen atoms stuck together right +we formed a chemical bond these two + + align:start position:0% +we formed a chemical bond these two + + + align:start position:0% +we formed a chemical bond these two +hydrogen atoms aren't going to fly apart + + align:start position:0% +hydrogen atoms aren't going to fly apart + + + align:start position:0% +hydrogen atoms aren't going to fly apart +that's what we wanted to + + align:start position:0% +that's what we wanted to + + + align:start position:0% +that's what we wanted to +do + + align:start position:0% +do + + + align:start position:0% +do +okay and therefore those two electrons + + align:start position:0% +okay and therefore those two electrons + + + align:start position:0% +okay and therefore those two electrons +here one for me hydrogen atom are + + align:start position:0% +here one for me hydrogen atom are + + + align:start position:0% +here one for me hydrogen atom are +sitting now in this new molecular state + + align:start position:0% +sitting now in this new molecular state + + + align:start position:0% +sitting now in this new molecular state +that we are calling Sigma 1s and the + + align:start position:0% +that we are calling Sigma 1s and the + + + align:start position:0% +that we are calling Sigma 1s and the +wave function then that describes the + + align:start position:0% +wave function then that describes the + + + align:start position:0% +wave function then that describes the +electrons in that state is a sigma 1s + + align:start position:0% +electrons in that state is a sigma 1s + + + align:start position:0% +electrons in that state is a sigma 1s +molecular wave + + align:start position:0% +molecular wave + + + align:start position:0% +molecular wave +function okay that's great everything + + align:start position:0% +function okay that's great everything + + + align:start position:0% +function okay that's great everything +looks + + align:start position:0% +looks + + + align:start position:0% +looks +cool except now that uh you know these + + align:start position:0% +cool except now that uh you know these + + + align:start position:0% +cool except now that uh you know these +are waves so not only can waves + + align:start position:0% +are waves so not only can waves + + + align:start position:0% +are waves so not only can waves +constructively interfere but hey they + + align:start position:0% +constructively interfere but hey they + + + align:start position:0% +constructively interfere but hey they +can destructively interfere too all + + align:start position:0% +can destructively interfere too all + + + align:start position:0% +can destructively interfere too all +right so we got to take care of that + + align:start position:0% +right so we got to take care of that + + + align:start position:0% +right so we got to take care of that +case now the case of destructive uh + + align:start position:0% +case now the case of destructive uh + + + align:start position:0% +case now the case of destructive uh +interference so let's uh let's do that + + align:start position:0% + + + + align:start position:0% + +all right in this case what's going to + + align:start position:0% +all right in this case what's going to + + + align:start position:0% +all right in this case what's going to +happen well again we have our 1s a wave + + align:start position:0% +happen well again we have our 1s a wave + + + align:start position:0% +happen well again we have our 1s a wave +function and our 1 SB W + + align:start position:0% +function and our 1 SB W + + + align:start position:0% +function and our 1 SB W +function and now when I'm going to bring + + align:start position:0% +function and now when I'm going to bring + + + align:start position:0% +function and now when I'm going to bring +these two together to the equilibrium + + align:start position:0% +these two together to the equilibrium + + + align:start position:0% +these two together to the equilibrium +Bond length AB here what's going to + + align:start position:0% +Bond length AB here what's going to + + + align:start position:0% +Bond length AB here what's going to +happen is in destructive + + align:start position:0% +happen is in destructive + + + align:start position:0% +happen is in destructive +interference this wave function is going + + align:start position:0% +interference this wave function is going + + + align:start position:0% +interference this wave function is going +to cancel this part of the wave + + align:start position:0% +to cancel this part of the wave + + + align:start position:0% +to cancel this part of the wave +function right when these overlap and I + + align:start position:0% +function right when these overlap and I + + + align:start position:0% +function right when these overlap and I +take this minus sign here or I'm + + align:start position:0% +take this minus sign here or I'm + + + align:start position:0% +take this minus sign here or I'm +superimposing two wave functions with + + align:start position:0% +superimposing two wave functions with + + + align:start position:0% +superimposing two wave functions with +different sign we're going to have + + align:start position:0% +different sign we're going to have + + + align:start position:0% +different sign we're going to have +destructive interference and the result + + align:start position:0% +destructive interference and the result + + + align:start position:0% +destructive interference and the result +is that the molecular wave function is + + align:start position:0% +is that the molecular wave function is + + + align:start position:0% +is that the molecular wave function is +going to kind of look like like + + align:start position:0% +going to kind of look like like + + + align:start position:0% +going to kind of look like like +this okay right in the center here hey + + align:start position:0% +this okay right in the center here hey + + + align:start position:0% +this okay right in the center here hey +there's going to be a node there's a + + align:start position:0% +there's going to be a node there's a + + + align:start position:0% +there's going to be a node there's a +node because this part of the wave + + align:start position:0% +node because this part of the wave + + + align:start position:0% +node because this part of the wave +function exactly cancel this part of the + + align:start position:0% +function exactly cancel this part of the + + + align:start position:0% +function exactly cancel this part of the +wave function hey there's no wave + + align:start position:0% +wave function hey there's no wave + + + align:start position:0% +wave function hey there's no wave +function right + + align:start position:0% +function right + + + align:start position:0% +function right +there all right because we have + + align:start position:0% +there all right because we have + + + align:start position:0% +there all right because we have +destructive + + align:start position:0% +destructive + + + align:start position:0% +destructive +interference how are we going to label + + align:start position:0% +interference how are we going to label + + + align:start position:0% +interference how are we going to label +this wave function well we're also going + + align:start position:0% +this wave function well we're also going + + + align:start position:0% +this wave function well we're also going +to call it a sigma wave function it's + + align:start position:0% +to call it a sigma wave function it's + + + align:start position:0% +to call it a sigma wave function it's +Sigma that's a symmetry because it's + + align:start position:0% +Sigma that's a symmetry because it's + + + align:start position:0% +Sigma that's a symmetry because it's +cylindrically symmetric around the + + align:start position:0% +cylindrically symmetric around the + + + align:start position:0% +cylindrically symmetric around the +axis right but because it is a linear + + align:start position:0% +axis right but because it is a linear + + + align:start position:0% +axis right but because it is a linear +combination + + align:start position:0% +combination + + + align:start position:0% +combination +here + + align:start position:0% +here + + + align:start position:0% +here +that is a consequence of destructive + + align:start position:0% +that is a consequence of destructive + + + align:start position:0% +that is a consequence of destructive +interference I'm going to call this + + align:start position:0% +interference I'm going to call this + + + align:start position:0% +interference I'm going to call this +Sigma + + align:start position:0% +Sigma + + + align:start position:0% +Sigma +star Sigma star + + align:start position:0% +star Sigma star + + + align:start position:0% +star Sigma star +1s and I'm going to call that Sigma star + + align:start position:0% +1s and I'm going to call that Sigma star + + + align:start position:0% +1s and I'm going to call that Sigma star +1s that's an anti-bonding + + align:start position:0% +1s that's an anti-bonding + + + align:start position:0% +1s that's an anti-bonding +orbital or an anti antibonding wave + + align:start position:0% +orbital or an anti antibonding wave + + + align:start position:0% +orbital or an anti antibonding wave +function okay now how do I know that + + align:start position:0% +function okay now how do I know that + + + align:start position:0% +function okay now how do I know that +well let's um let's also calculate the + + align:start position:0% +well let's um let's also calculate the + + + align:start position:0% +well let's um let's also calculate the +probability density here for Sigma 1s + + align:start position:0% +probability density here for Sigma 1s + + + align:start position:0% +probability density here for Sigma 1s +star hey that's going to be uh that's + + align:start position:0% +star hey that's going to be uh that's + + + align:start position:0% +star hey that's going to be uh that's +going to be interesting so we got P + + align:start position:0% +going to be interesting so we got P + + + align:start position:0% +going to be interesting so we got P +probability density Sigma 1 s star + + align:start position:0% +probability density Sigma 1 s star + + + align:start position:0% +probability density Sigma 1 s star +Square it right so I have now a one s a + + align:start position:0% +Square it right so I have now a one s a + + + align:start position:0% +Square it right so I have now a one s a +- 1 + + align:start position:0% +- 1 + + + align:start position:0% +- 1 +SB time 1s + + align:start position:0% +SB time 1s + + + align:start position:0% +SB time 1s +Aus 1 + + align:start position:0% +Aus 1 + + + align:start position:0% +Aus 1 +SB multiply that out so I get + + align:start position:0% +SB multiply that out so I get + + + align:start position:0% +SB multiply that out so I get +1sa quty squared plus 1 + + align:start position:0% +1sa quty squared plus 1 + + + align:start position:0% +1sa quty squared plus 1 +sban squar minus 2 * 1s + + align:start position:0% +sban squar minus 2 * 1s + + + align:start position:0% +sban squar minus 2 * 1s +a * 1 SB hey I'm now going to plot this + + align:start position:0% +a * 1 SB hey I'm now going to plot this + + + align:start position:0% +a * 1 SB hey I'm now going to plot this +on my graph here all right so this is + + align:start position:0% +on my graph here all right so this is + + + align:start position:0% +on my graph here all right so this is +what I'm plotting right on my graph of + + align:start position:0% +what I'm plotting right on my graph of + + + align:start position:0% +what I'm plotting right on my graph of +the probability density when I do that + + align:start position:0% +the probability density when I do that + + + align:start position:0% +the probability density when I do that +well okay way out here right on one end + + align:start position:0% +well okay way out here right on one end + + + align:start position:0% +well okay way out here right on one end +of the molecule probability density is + + align:start position:0% +of the molecule probability density is + + + align:start position:0% +of the molecule probability density is +pretty low probability density goes to a + + align:start position:0% +pretty low probability density goes to a + + + align:start position:0% +pretty low probability density goes to a +maximum right at the nucleus and then it + + align:start position:0% +maximum right at the nucleus and then it + + + align:start position:0% +maximum right at the nucleus and then it +plummets right and right at the center + + align:start position:0% +plummets right and right at the center + + + align:start position:0% +plummets right and right at the center +here right at the center here the + + align:start position:0% +here right at the center here the + + + align:start position:0% +here right at the center here the +probability density is zero because the + + align:start position:0% +probability density is zero because the + + + align:start position:0% +probability density is zero because the +wave function's zero because we had + + align:start position:0% +wave function's zero because we had + + + align:start position:0% +wave function's zero because we had +destructive + + align:start position:0% +destructive + + + align:start position:0% +destructive +interference okay hey I want you to + + align:start position:0% +interference okay hey I want you to + + + align:start position:0% +interference okay hey I want you to +notice something probability density + + align:start position:0% +notice something probability density + + + align:start position:0% +notice something probability density +here is + + align:start position:0% +here is + + + align:start position:0% +here is +zero it is even lower than this case + + align:start position:0% +zero it is even lower than this case + + + align:start position:0% +zero it is even lower than this case +this case which is just the sum of two + + align:start position:0% +this case which is just the sum of two + + + align:start position:0% +this case which is just the sum of two +hydrogen atoms their wave function + + align:start position:0% +hydrogen atoms their wave function + + + align:start position:0% +hydrogen atoms their wave function +squared in the case when the two + + align:start position:0% +squared in the case when the two + + + align:start position:0% +squared in the case when the two +hydrogen atoms aren't interacting the + + align:start position:0% +hydrogen atoms aren't interacting the + + + align:start position:0% +hydrogen atoms aren't interacting the +probability density is some finite value + + align:start position:0% +probability density is some finite value + + + align:start position:0% +probability density is some finite value +but in the case of this antibonding + + align:start position:0% +but in the case of this antibonding + + + align:start position:0% +but in the case of this antibonding +state right the probability density is + + align:start position:0% +state right the probability density is + + + align:start position:0% +state right the probability density is +zero Goose zip NADA all of the other + + align:start position:0% +zero Goose zip NADA all of the other + + + align:start position:0% +zero Goose zip NADA all of the other +things right there's nothing there this + + align:start position:0% +things right there's nothing there this + + + align:start position:0% +things right there's nothing there this +state here that we're forming it's + + align:start position:0% +state here that we're forming it's + + + align:start position:0% +state here that we're forming it's +antibonding it's not even nonbonding + + align:start position:0% +antibonding it's not even nonbonding + + + align:start position:0% +antibonding it's not even nonbonding +non-bonding right it's got more electron + + align:start position:0% +non-bonding right it's got more electron + + + align:start position:0% +non-bonding right it's got more electron +density the microphone + + align:start position:0% +density the microphone + + + align:start position:0% +density the microphone +here all right all + + align:start position:0% + + + + align:start position:0% + +right non-bonding has more electron + + align:start position:0% +right non-bonding has more electron + + + align:start position:0% +right non-bonding has more electron +density than antibonding hey this is + + align:start position:0% +density than antibonding hey this is + + + align:start position:0% +density than antibonding hey this is +anti bonding against + + align:start position:0% +anti bonding against + + + align:start position:0% +anti bonding against +bonding okay that's the kind of state we + + align:start position:0% +bonding okay that's the kind of state we + + + align:start position:0% +bonding okay that's the kind of state we +just formed by destructive + + align:start position:0% +just formed by destructive + + + align:start position:0% +just formed by destructive +interference + + align:start position:0% +interference + + + align:start position:0% +interference +so where do you think in an energy + + align:start position:0% +so where do you think in an energy + + + align:start position:0% +so where do you think in an energy +diagram where do you think the sigma One + + align:start position:0% +diagram where do you think the sigma One + + + align:start position:0% +diagram where do you think the sigma One +S Star level is well you can imagine + + align:start position:0% +S Star level is well you can imagine + + + align:start position:0% +S Star level is well you can imagine +where it is it's increased in energy + + align:start position:0% +where it is it's increased in energy + + + align:start position:0% +where it is it's increased in energy +it's up here Sigma 1 s + + align:start position:0% +it's up here Sigma 1 s + + + align:start position:0% +it's up here Sigma 1 s +star and it turns out that the amount of + + align:start position:0% +star and it turns out that the amount of + + + align:start position:0% +star and it turns out that the amount of +energy above the energy for the two + + align:start position:0% +energy above the energy for the two + + + align:start position:0% +energy above the energy for the two +separated hydrogen atoms that this state + + align:start position:0% +separated hydrogen atoms that this state + + + align:start position:0% +separated hydrogen atoms that this state +lies is about equal to the amount of + + align:start position:0% +lies is about equal to the amount of + + + align:start position:0% +lies is about equal to the amount of +energy below the separated atoms that + + align:start position:0% +energy below the separated atoms that + + + align:start position:0% +energy below the separated atoms that +this state lies these two energies are + + align:start position:0% +this state lies these two energies are + + + align:start position:0% +this state lies these two energies are +about equivalent all right + + align:start position:0% +about equivalent all right + + + align:start position:0% +about equivalent all right +so we now have a bonding state or a + + align:start position:0% +so we now have a bonding state or a + + + align:start position:0% +so we now have a bonding state or a +bonding orbital we now have an + + align:start position:0% +bonding orbital we now have an + + + align:start position:0% +bonding orbital we now have an +antibonding state or an anti-bonding + + align:start position:0% +antibonding state or an anti-bonding + + + align:start position:0% +antibonding state or an anti-bonding +orbital + + align:start position:0% +orbital + + + align:start position:0% +orbital +okay now when do we use that + + align:start position:0% +okay now when do we use that + + + align:start position:0% +okay now when do we use that +anti-bonding orbital well we're going to + + align:start position:0% +anti-bonding orbital well we're going to + + + align:start position:0% +anti-bonding orbital well we're going to +see in a moment but one case would be if + + align:start position:0% +see in a moment but one case would be if + + + align:start position:0% +see in a moment but one case would be if +we had an excited state of a hydrogen + + align:start position:0% +we had an excited state of a hydrogen + + + align:start position:0% +we had an excited state of a hydrogen +molecule hey in an excited state what we + + align:start position:0% +molecule hey in an excited state what we + + + align:start position:0% +molecule hey in an excited state what we +could do is we could take one of these + + align:start position:0% +could do is we could take one of these + + + align:start position:0% +could do is we could take one of these +electrons my Eraser is kind of wet here + + align:start position:0% +electrons my Eraser is kind of wet here + + + align:start position:0% +electrons my Eraser is kind of wet here +so it's not + + align:start position:0% +so it's not + + + align:start position:0% +so it's not +erasing let me try + + align:start position:0% +erasing let me try + + + align:start position:0% +erasing let me try +this I could take one of these electrons + + align:start position:0% +this I could take one of these electrons + + + align:start position:0% +this I could take one of these electrons +here right and populate it and put it in + + align:start position:0% +here right and populate it and put it in + + + align:start position:0% +here right and populate it and put it in +this state that's the first excited + + align:start position:0% +this state that's the first excited + + + align:start position:0% +this state that's the first excited +state of H2 not H + + align:start position:0% +state of H2 not H + + + align:start position:0% +state of H2 not H +H2 a second excited state would be take + + align:start position:0% +H2 a second excited state would be take + + + align:start position:0% +H2 a second excited state would be take +hey this is a permanent chalk once it + + align:start position:0% +hey this is a permanent chalk once it + + + align:start position:0% +hey this is a permanent chalk once it +gets wet all right the second uh excited + + align:start position:0% +gets wet all right the second uh excited + + + align:start position:0% +gets wet all right the second uh excited +state will be taking that second + + align:start position:0% +state will be taking that second + + + align:start position:0% +state will be taking that second +electron and promoting it to this + + align:start position:0% +electron and promoting it to this + + + align:start position:0% +electron and promoting it to this +anti-bonding state that would be the + + align:start position:0% +anti-bonding state that would be the + + + align:start position:0% +anti-bonding state that would be the +second excited state of molecular + + align:start position:0% +second excited state of molecular + + + align:start position:0% +second excited state of molecular +hydrogen now I got to tell you if you + + align:start position:0% +hydrogen now I got to tell you if you + + + align:start position:0% +hydrogen now I got to tell you if you +have these kinds of excited states of + + align:start position:0% +have these kinds of excited states of + + + align:start position:0% +have these kinds of excited states of +molecular hydrogen molecular hydrogen + + align:start position:0% +molecular hydrogen molecular hydrogen + + + align:start position:0% +molecular hydrogen molecular hydrogen +doesn't stick around right it's going to + + align:start position:0% +doesn't stick around right it's going to + + + align:start position:0% +doesn't stick around right it's going to +fall + + align:start position:0% +fall + + + align:start position:0% +fall +apart okay but the ground state + + align:start position:0% +apart okay but the ground state + + + align:start position:0% +apart okay but the ground state +configuration of H2 + + align:start position:0% +configuration of H2 + + + align:start position:0% +configuration of H2 +has these two electrons here in the + + align:start position:0% +has these two electrons here in the + + + align:start position:0% +has these two electrons here in the +sigma 1s + + align:start position:0% +sigma 1s + + + align:start position:0% +sigma 1s +State I also just want to point out here + + align:start position:0% +State I also just want to point out here + + + align:start position:0% +State I also just want to point out here +what the significance physically is of + + align:start position:0% +what the significance physically is of + + + align:start position:0% +what the significance physically is of +the separation in energy between the + + align:start position:0% +the separation in energy between the + + + align:start position:0% +the separation in energy between the +hydrogen atom States and the molecular + + align:start position:0% +hydrogen atom States and the molecular + + + align:start position:0% +hydrogen atom States and the molecular +hydrogen State all right here's the + + align:start position:0% +hydrogen State all right here's the + + + align:start position:0% +hydrogen State all right here's the +significance remember we drew a uh + + align:start position:0% +significance remember we drew a uh + + + align:start position:0% +significance remember we drew a uh +an energy of interaction for molecular + + align:start position:0% +an energy of interaction for molecular + + + align:start position:0% +an energy of interaction for molecular +hydrogen we talked about the + + align:start position:0% +hydrogen we talked about the + + + align:start position:0% +hydrogen we talked about the +general principles in the general + + align:start position:0% +general principles in the general + + + align:start position:0% +general principles in the general +attractions and repulsions that take + + align:start position:0% +attractions and repulsions that take + + + align:start position:0% +attractions and repulsions that take +place in every chemical bond and the + + align:start position:0% +place in every chemical bond and the + + + align:start position:0% +place in every chemical bond and the +result was a curve that kind of looked + + align:start position:0% +result was a curve that kind of looked + + + align:start position:0% +result was a curve that kind of looked +like this where this is hydrogen two + + align:start position:0% +like this where this is hydrogen two + + + align:start position:0% +like this where this is hydrogen two +separated hydrogen atoms this is of + + align:start position:0% +separated hydrogen atoms this is of + + + align:start position:0% +separated hydrogen atoms this is of +course equilibrium Bond length of H2 the + + align:start position:0% +course equilibrium Bond length of H2 the + + + align:start position:0% +course equilibrium Bond length of H2 the +molecules bonded here everywhere where + + align:start position:0% +molecules bonded here everywhere where + + + align:start position:0% +molecules bonded here everywhere where +this energy is lower than the separated + + align:start position:0% +this energy is lower than the separated + + + align:start position:0% +this energy is lower than the separated +hydrogen atom limit okay well the + + align:start position:0% +hydrogen atom limit okay well the + + + align:start position:0% +hydrogen atom limit okay well the +physical significance here of this + + align:start position:0% +physical significance here of this + + + align:start position:0% +physical significance here of this +energy lowering of this state is well + + align:start position:0% +energy lowering of this state is well + + + align:start position:0% +energy lowering of this state is well +you know this is essentially Delta e + + align:start position:0% +you know this is essentially Delta e + + + align:start position:0% +you know this is essentially Delta e +subd right this is essentially the bond + + align:start position:0% +subd right this is essentially the bond + + + align:start position:0% +subd right this is essentially the bond +strength of molecular hydrogen that's + + align:start position:0% +strength of molecular hydrogen that's + + + align:start position:0% +strength of molecular hydrogen that's +what that is + + align:start position:0% +what that is + + + align:start position:0% +what that is +physically + + align:start position:0% +physically + + + align:start position:0% +physically +okay right this energy from here here + + align:start position:0% +okay right this energy from here here + + + align:start position:0% +okay right this energy from here here +that's what it's going to take to pull + + align:start position:0% +that's what it's going to take to pull + + + align:start position:0% +that's what it's going to take to pull +the hydrogen atoms apart the bond + + align:start position:0% +the hydrogen atoms apart the bond + + + align:start position:0% +the hydrogen atoms apart the bond +energy okay + + align:start position:0% +energy okay + + + align:start position:0% +energy okay +so we took care of hydrogen we have two + + align:start position:0% +so we took care of hydrogen we have two + + + align:start position:0% +so we took care of hydrogen we have two +molecular + + align:start position:0% +molecular + + + align:start position:0% +molecular +States bonding antibonding for the + + align:start position:0% +States bonding antibonding for the + + + align:start position:0% +States bonding antibonding for the +ground state hydrogen both electrons are + + align:start position:0% +ground state hydrogen both electrons are + + + align:start position:0% +ground state hydrogen both electrons are +in that bonding + + align:start position:0% +in that bonding + + + align:start position:0% +in that bonding +state so now let's walk across the + + align:start position:0% +state so now let's walk across the + + + align:start position:0% +state so now let's walk across the +periodic + + align:start position:0% +periodic + + + align:start position:0% +periodic +table let's um oh okay one other thing + + align:start position:0% +table let's um oh okay one other thing + + + align:start position:0% +table let's um oh okay one other thing +if you were asked to write the electron + + align:start position:0% +if you were asked to write the electron + + + align:start position:0% +if you were asked to write the electron +configuration of molecular hydrogen in + + align:start position:0% +configuration of molecular hydrogen in + + + align:start position:0% +configuration of molecular hydrogen in +the ground state what would you do well + + align:start position:0% +the ground state what would you do well + + + align:start position:0% +the ground state what would you do well +the electron configuration of molecular + + align:start position:0% +the electron configuration of molecular + + + align:start position:0% +the electron configuration of molecular +hydrogen then the way we would write it + + align:start position:0% +hydrogen then the way we would write it + + + align:start position:0% +hydrogen then the way we would write it +is Sigma + + align:start position:0% +is Sigma + + + align:start position:0% +is Sigma +1s2 meaning two electrons in the sigma + + align:start position:0% +1s2 meaning two electrons in the sigma + + + align:start position:0% +1s2 meaning two electrons in the sigma +1s State and just to be complete here + + align:start position:0% +1s State and just to be complete here + + + align:start position:0% +1s State and just to be complete here +you could write this antibonding state + + align:start position:0% +you could write this antibonding state + + + align:start position:0% +you could write this antibonding state +as Sigma 1est star with zero electrons + + align:start position:0% +as Sigma 1est star with zero electrons + + + align:start position:0% +as Sigma 1est star with zero electrons +in it all right that would be the + + align:start position:0% +in it all right that would be the + + + align:start position:0% +in it all right that would be the +electron + + align:start position:0% +electron + + + align:start position:0% +electron +configuration okay well now what we're + + align:start position:0% +configuration okay well now what we're + + + align:start position:0% +configuration okay well now what we're +going to want to do is to write the um + + align:start position:0% +going to want to do is to write the um + + + align:start position:0% +going to want to do is to write the um +electron configuration for the next + + align:start position:0% +electron configuration for the next + + + align:start position:0% +electron configuration for the next +molecule as we walk across the periodic + + align:start position:0% +molecule as we walk across the periodic + + + align:start position:0% +molecule as we walk across the periodic +table the next diatomic molecule hey the + + align:start position:0% +table the next diatomic molecule hey the + + + align:start position:0% +table the next diatomic molecule hey the +next diatomic molecule is going to be + + align:start position:0% +next diatomic molecule is going to be + + + align:start position:0% +next diatomic molecule is going to be +helium 2 right + + align:start position:0% + + + + align:start position:0% + +okay so where are the electrons in the + + align:start position:0% +okay so where are the electrons in the + + + align:start position:0% +okay so where are the electrons in the +case of helium + + align:start position:0% +case of helium + + + align:start position:0% +case of helium +2 well in the case of + + align:start position:0% +2 well in the case of + + + align:start position:0% +2 well in the case of +helium + + align:start position:0% +helium + + + align:start position:0% +helium +each helium atom brings in two electrons + + align:start position:0% +each helium atom brings in two electrons + + + align:start position:0% +each helium atom brings in two electrons +each helium atom has an electron has two + + align:start position:0% +each helium atom has an electron has two + + + align:start position:0% +each helium atom has an electron has two +electrons here in the 1s state so I'm + + align:start position:0% +electrons here in the 1s state so I'm + + + align:start position:0% +electrons here in the 1s state so I'm +now drawing this for helium all right + + align:start position:0% +now drawing this for helium all right + + + align:start position:0% +now drawing this for helium all right +and the way we draw this correlation + + align:start position:0% +and the way we draw this correlation + + + align:start position:0% +and the way we draw this correlation +diagram as it's called is following the + + align:start position:0% +diagram as it's called is following the + + + align:start position:0% +diagram as it's called is following the +sou bow principle that we had for + + align:start position:0% +sou bow principle that we had for + + + align:start position:0% +sou bow principle that we had for +filling Atomic + + align:start position:0% +filling Atomic + + + align:start position:0% +filling Atomic +States right that is we take the states + + align:start position:0% +States right that is we take the states + + + align:start position:0% +States right that is we take the states +we order them in terms of their energy + + align:start position:0% +we order them in terms of their energy + + + align:start position:0% +we order them in terms of their energy +lowest energy at the bottom next highest + + align:start position:0% +lowest energy at the bottom next highest + + + align:start position:0% +lowest energy at the bottom next highest +energy and then we start to put + + align:start position:0% +energy and then we start to put + + + align:start position:0% +energy and then we start to put +electrons in those States one at a + + align:start position:0% +electrons in those States one at a + + + align:start position:0% +electrons in those States one at a +time until we starting at the bottom + + align:start position:0% +time until we starting at the bottom + + + align:start position:0% +time until we starting at the bottom +starting at the lowest energy until we + + align:start position:0% +starting at the lowest energy until we + + + align:start position:0% +starting at the lowest energy until we +run out of electrons so that's what + + align:start position:0% +run out of electrons so that's what + + + align:start position:0% +run out of electrons so that's what +we're going to do for helium all right + + align:start position:0% +we're going to do for helium all right + + + align:start position:0% +we're going to do for helium all right +so what's going to happen two of these + + align:start position:0% +so what's going to happen two of these + + + align:start position:0% +so what's going to happen two of these +electrons are going to be in the bonding + + align:start position:0% +electrons are going to be in the bonding + + + align:start position:0% +electrons are going to be in the bonding +State and then two of these electrons + + align:start position:0% +State and then two of these electrons + + + align:start position:0% +State and then two of these electrons +are going to be in the antibonding state + + align:start position:0% +are going to be in the antibonding state + + + align:start position:0% +are going to be in the antibonding state +and so the electron configuration here + + align:start position:0% +and so the electron configuration here + + + align:start position:0% +and so the electron configuration here +for helium is 1 + + align:start position:0% +for helium is 1 + + + align:start position:0% +for helium is 1 +S2 Sigma 1 s star 2 that's the electron + + align:start position:0% +S2 Sigma 1 s star 2 that's the electron + + + align:start position:0% +S2 Sigma 1 s star 2 that's the electron +configuration for helium + + align:start position:0% +configuration for helium + + + align:start position:0% +configuration for helium +dimer all right but hey this is + + align:start position:0% +dimer all right but hey this is + + + align:start position:0% +dimer all right but hey this is +interesting because + + align:start position:0% +interesting because + + + align:start position:0% +interesting because +look we have now in this molecular state + + align:start position:0% +look we have now in this molecular state + + + align:start position:0% +look we have now in this molecular state +two + + align:start position:0% +two + + + align:start position:0% +two +electrons that um are at an energy that + + align:start position:0% +electrons that um are at an energy that + + + align:start position:0% +electrons that um are at an energy that +is lower than the two separated helium + + align:start position:0% +is lower than the two separated helium + + + align:start position:0% +is lower than the two separated helium +atom limit and two electrons that are + + align:start position:0% +atom limit and two electrons that are + + + align:start position:0% +atom limit and two electrons that are +higher hey it seems like there wasn't a + + align:start position:0% +higher hey it seems like there wasn't a + + + align:start position:0% +higher hey it seems like there wasn't a +an overall stabilization of this + + align:start position:0% +an overall stabilization of this + + + align:start position:0% +an overall stabilization of this +molecule right because we have one state + + align:start position:0% +molecule right because we have one state + + + align:start position:0% +molecule right because we have one state +that is lower in + + align:start position:0% +that is lower in + + + align:start position:0% +that is lower in +energy and another state that is higher + + align:start position:0% +energy and another state that is higher + + + align:start position:0% +energy and another state that is higher +in energy by the same amount so the + + align:start position:0% +in energy by the same amount so the + + + align:start position:0% +in energy by the same amount so the +overall is hey + + align:start position:0% +overall is hey + + + align:start position:0% +overall is hey +Zippo okay and indeed that is the case + + align:start position:0% +Zippo okay and indeed that is the case + + + align:start position:0% +Zippo okay and indeed that is the case +so uh we've got a tool for uh + + align:start position:0% +so uh we've got a tool for uh + + + align:start position:0% +so uh we've got a tool for uh +counting um or for telling + + align:start position:0% +counting um or for telling + + + align:start position:0% +counting um or for telling +how strong the bond is and that tool is + + align:start position:0% +how strong the bond is and that tool is + + + align:start position:0% +how strong the bond is and that tool is +called the bond + + align:start position:0% + + + + align:start position:0% + +order the bond order is defined + + align:start position:0% + + + + align:start position:0% + +as2 the + + align:start position:0% +as2 the + + + align:start position:0% +as2 the +number of bonding + + align:start position:0% + + + + align:start position:0% + +electrons minus the number of + + align:start position:0% +electrons minus the number of + + + align:start position:0% +electrons minus the number of +anti-bonding + + align:start position:0% + + + + align:start position:0% + +electrons all right so in the case of + + align:start position:0% +electrons all right so in the case of + + + align:start position:0% +electrons all right so in the case of +helium 2 we've got two bonding electrons + + align:start position:0% +helium 2 we've got two bonding electrons + + + align:start position:0% +helium 2 we've got two bonding electrons +and two anti-bonding electrons hey in + + align:start position:0% +and two anti-bonding electrons hey in + + + align:start position:0% +and two anti-bonding electrons hey in +the case of helium 2 the bond order here + + align:start position:0% +the case of helium 2 the bond order here + + + align:start position:0% +the case of helium 2 the bond order here +is equal to zero when you have a bond + + align:start position:0% +is equal to zero when you have a bond + + + align:start position:0% +is equal to zero when you have a bond +order equal to zero what that means is + + align:start position:0% +order equal to zero what that means is + + + align:start position:0% +order equal to zero what that means is +that you have no + + align:start position:0% +that you have no + + + align:start position:0% +that you have no +bond all right and indeed that is the + + align:start position:0% +bond all right and indeed that is the + + + align:start position:0% +bond all right and indeed that is the +case helium + + align:start position:0% +case helium + + + align:start position:0% +case helium +2 has no bond between them okay now + + align:start position:0% +2 has no bond between them okay now + + + align:start position:0% +2 has no bond between them okay now +accurately speaking helium 2 does have a + + align:start position:0% +accurately speaking helium 2 does have a + + + align:start position:0% +accurately speaking helium 2 does have a +bond between them right uh helium 2 was + + align:start position:0% +bond between them right uh helium 2 was + + + align:start position:0% +bond between them right uh helium 2 was +discovered so to speak in + + align:start position:0% +discovered so to speak in + + + align:start position:0% +discovered so to speak in +1993 and it was made under really very + + align:start position:0% +1993 and it was made under really very + + + align:start position:0% +1993 and it was made under really very +special conditions and the bond + + align:start position:0% +special conditions and the bond + + + align:start position:0% +special conditions and the bond +strength here of helium 2 is a whopping + + align:start position:0% +strength here of helium 2 is a whopping + + + align:start position:0% +strength here of helium 2 is a whopping +0.01 kilj per mole that's for helium too + + align:start position:0% +0.01 kilj per mole that's for helium too + + + align:start position:0% +0.01 kilj per mole that's for helium too +right whereas for example the bond + + align:start position:0% +right whereas for example the bond + + + align:start position:0% +right whereas for example the bond +strength in hydrogen is + + align:start position:0% +strength in hydrogen is + + + align:start position:0% +strength in hydrogen is +432 K per + + align:start position:0% +432 K per + + + align:start position:0% +432 K per +mole so you can see how weak a bond that + + align:start position:0% +mole so you can see how weak a bond that + + + align:start position:0% +mole so you can see how weak a bond that +is effectively this is no bond at all + + align:start position:0% +is effectively this is no bond at all + + + align:start position:0% +is effectively this is no bond at all +all right practically speaking and so + + align:start position:0% +all right practically speaking and so + + + align:start position:0% +all right practically speaking and so +molecular orbital Theory really gets it + + align:start position:0% +molecular orbital Theory really gets it + + + align:start position:0% +molecular orbital Theory really gets it +right in the sense that it tells you hey + + align:start position:0% +right in the sense that it tells you hey + + + align:start position:0% +right in the sense that it tells you hey +there's no bond here + + align:start position:0% +there's no bond here + + + align:start position:0% +there's no bond here +okay + + align:start position:0% +okay + + + align:start position:0% +okay +okay great + + align:start position:0% +okay great + + + align:start position:0% +okay great +all right so now um what we're going to + + align:start position:0% +all right so now um what we're going to + + + align:start position:0% +all right so now um what we're going to +do is we're going to keep marching + + align:start position:0% +do is we're going to keep marching + + + align:start position:0% +do is we're going to keep marching +across the periodic table actually we've + + align:start position:0% +across the periodic table actually we've + + + align:start position:0% +across the periodic table actually we've +got to go down one row now and um let's + + align:start position:0% +got to go down one row now and um let's + + + align:start position:0% +got to go down one row now and um let's +uh look at the electron configuration + + align:start position:0% +uh look at the electron configuration + + + align:start position:0% +uh look at the electron configuration +for lithium + + align:start position:0% + + + + align:start position:0% + +dier all + + align:start position:0% +dier all + + + align:start position:0% +dier all +right + + align:start position:0% +right + + + align:start position:0% +right +now if we're going to bring together two + + align:start position:0% +now if we're going to bring together two + + + align:start position:0% +now if we're going to bring together two +lithium + + align:start position:0% +lithium + + + align:start position:0% +lithium +atoms lithium has two electrons uh that + + align:start position:0% +atoms lithium has two electrons uh that + + + align:start position:0% +atoms lithium has two electrons uh that +are in the 1s State and one electron + + align:start position:0% +are in the 1s State and one electron + + + align:start position:0% +are in the 1s State and one electron +each in a 2s + + align:start position:0% +each in a 2s + + + align:start position:0% +each in a 2s +State and let me put them in all right + + align:start position:0% +State and let me put them in all right + + + align:start position:0% +State and let me put them in all right +so those are the electron configurations + + align:start position:0% +so those are the electron configurations + + + align:start position:0% +so those are the electron configurations +for the two separated lithium + + align:start position:0% +for the two separated lithium + + + align:start position:0% +for the two separated lithium +atoms so how do we write this electron + + align:start position:0% +atoms so how do we write this electron + + + align:start position:0% +atoms so how do we write this electron +configuration well again we follow the + + align:start position:0% +configuration well again we follow the + + + align:start position:0% +configuration well again we follow the +albow principle we put two electrons + + align:start position:0% +albow principle we put two electrons + + + align:start position:0% +albow principle we put two electrons +here two electrons here but now since + + align:start position:0% +here two electrons here but now since + + + align:start position:0% +here two electrons here but now since +we've got these 2 s electrons what we're + + align:start position:0% +we've got these 2 s electrons what we're + + + align:start position:0% +we've got these 2 s electrons what we're +going to have to do is to form molecular + + align:start position:0% +going to have to do is to form molecular + + + align:start position:0% +going to have to do is to form molecular +States molecular + + align:start position:0% +States molecular + + + align:start position:0% +States molecular +orbitals between these 2s Atomic + + align:start position:0% +orbitals between these 2s Atomic + + + align:start position:0% +orbitals between these 2s Atomic +orbitals and the 2s Atomic + + align:start position:0% +orbitals and the 2s Atomic + + + align:start position:0% +orbitals and the 2s Atomic +orbitals form these molecular states in + + align:start position:0% +orbitals form these molecular states in + + + align:start position:0% +orbitals form these molecular states in +the same way that the 1s Atomic orbitals + + align:start position:0% +the same way that the 1s Atomic orbitals + + + align:start position:0% +the same way that the 1s Atomic orbitals +do hey they're all spherically symmetric + + align:start position:0% +do hey they're all spherically symmetric + + + align:start position:0% +do hey they're all spherically symmetric +all right so they formed these orbitals + + align:start position:0% +all right so they formed these orbitals + + + align:start position:0% +all right so they formed these orbitals +in absolutely the same way and so you + + align:start position:0% +in absolutely the same way and so you + + + align:start position:0% +in absolutely the same way and so you +get a sigma 2s bonding State and a sigma + + align:start position:0% +get a sigma 2s bonding State and a sigma + + + align:start position:0% +get a sigma 2s bonding State and a sigma +2s Star antibonding + + align:start position:0% +2s Star antibonding + + + align:start position:0% +2s Star antibonding +State so if you want to write the + + align:start position:0% +State so if you want to write the + + + align:start position:0% +State so if you want to write the +correlation diagram as this called as + + align:start position:0% +correlation diagram as this called as + + + align:start position:0% +correlation diagram as this called as +it's called for lithium 2 you take all + + align:start position:0% +it's called for lithium 2 you take all + + + align:start position:0% +it's called for lithium 2 you take all +of lithium's electrons and you now put + + align:start position:0% +of lithium's electrons and you now put + + + align:start position:0% +of lithium's electrons and you now put +it in the lowest energy State put it in + + align:start position:0% +it in the lowest energy State put it in + + + align:start position:0% +it in the lowest energy State put it in +the next highest energy State and put it + + align:start position:0% +the next highest energy State and put it + + + align:start position:0% +the next highest energy State and put it +in the next highest energy State that's + + align:start position:0% +in the next highest energy State that's + + + align:start position:0% +in the next highest energy State that's +the correlation diagram we ran out of + + align:start position:0% +the correlation diagram we ran out of + + + align:start position:0% +the correlation diagram we ran out of +electrons we had six six electrons total + + align:start position:0% +electrons we had six six electrons total + + + align:start position:0% +electrons we had six six electrons total +so the electron configuration written + + align:start position:0% +so the electron configuration written + + + align:start position:0% +so the electron configuration written +here is this Sigma 1 S2 Sigma 1 s star + + align:start position:0% +here is this Sigma 1 S2 Sigma 1 s star + + + align:start position:0% +here is this Sigma 1 S2 Sigma 1 s star +to Sigma 2 + + align:start position:0% +to Sigma 2 + + + align:start position:0% +to Sigma 2 +S2 all right what's the bond order here + + align:start position:0% +S2 all right what's the bond order here + + + align:start position:0% +S2 all right what's the bond order here +hey let's calculate it we have two four + + align:start position:0% +hey let's calculate it we have two four + + + align:start position:0% +hey let's calculate it we have two four +bonding electrons we got two + + align:start position:0% +bonding electrons we got two + + + align:start position:0% +bonding electrons we got two +anti-bonding electrons 4 - 2 / 2 is 1 + + align:start position:0% +anti-bonding electrons 4 - 2 / 2 is 1 + + + align:start position:0% +anti-bonding electrons 4 - 2 / 2 is 1 +all right we got bond order of one that + + align:start position:0% +all right we got bond order of one that + + + align:start position:0% +all right we got bond order of one that +means we got a single bond that bond + + align:start position:0% +means we got a single bond that bond + + + align:start position:0% +means we got a single bond that bond +strength is 105 K per mole that's a + + align:start position:0% +strength is 105 K per mole that's a + + + align:start position:0% +strength is 105 K per mole that's a +single Bond it's a weak single Bond but + + align:start position:0% +single Bond it's a weak single Bond but + + + align:start position:0% +single Bond it's a weak single Bond but +that's a single Bond + + align:start position:0% + + + + align:start position:0% + +okay okay what about + + align:start position:0% +okay okay what about + + + align:start position:0% +okay okay what about +brillium let's make brillium to + + align:start position:0% + + + + align:start position:0% + +yes I'm + + align:start position:0% + + + + align:start position:0% + +sorry how did these two get up here okay + + align:start position:0% +sorry how did these two get up here okay + + + align:start position:0% +sorry how did these two get up here okay +these electrons right are the electrons + + align:start position:0% +these electrons right are the electrons + + + align:start position:0% +these electrons right are the electrons +on the atom so the lithium atom has two + + align:start position:0% +on the atom so the lithium atom has two + + + align:start position:0% +on the atom so the lithium atom has two +1s electrons and one 2s electron + + align:start position:0% +1s electrons and one 2s electron + + + align:start position:0% +1s electrons and one 2s electron +okay and this is the energy ordering for + + align:start position:0% +okay and this is the energy ordering for + + + align:start position:0% +okay and this is the energy ordering for +the atomic States in lithium okay the + + align:start position:0% +the atomic States in lithium okay the + + + align:start position:0% +the atomic States in lithium okay the +molecular state for um lithium here or + + align:start position:0% +molecular state for um lithium here or + + + align:start position:0% +molecular state for um lithium here or +the sigma 2s state it is higher in + + align:start position:0% +the sigma 2s state it is higher in + + + align:start position:0% +the sigma 2s state it is higher in +energy than the sigma 1s star this is + + align:start position:0% +energy than the sigma 1s star this is + + + align:start position:0% +energy than the sigma 1s star this is +the correct level ordering of the + + align:start position:0% +the correct level ordering of the + + + align:start position:0% +the correct level ordering of the +energies of these states okay I didn't + + align:start position:0% +energies of these states okay I didn't + + + align:start position:0% +energies of these states okay I didn't +clearly explain that to you all right + + align:start position:0% +clearly explain that to you all right + + + align:start position:0% +clearly explain that to you all right +does that make sense yeah okay all + + align:start position:0% +does that make sense yeah okay all + + + align:start position:0% +does that make sense yeah okay all +right okay so now we'll uh go to + + align:start position:0% +right okay so now we'll uh go to + + + align:start position:0% +right okay so now we'll uh go to +brillium + + align:start position:0% +brillium + + + align:start position:0% +brillium +dier and now we got two 2s + + align:start position:0% +dier and now we got two 2s + + + align:start position:0% +dier and now we got two 2s +electrons so again what do we do we put + + align:start position:0% +electrons so again what do we do we put + + + align:start position:0% +electrons so again what do we do we put +two of the electrons in the lowest + + align:start position:0% +two of the electrons in the lowest + + + align:start position:0% +two of the electrons in the lowest +energy state two in the next highest + + align:start position:0% +energy state two in the next highest + + + align:start position:0% +energy state two in the next highest +energy state two in the next highest + + align:start position:0% +energy state two in the next highest + + + align:start position:0% +energy state two in the next highest +energy State and another two in the next + + align:start position:0% +energy State and another two in the next + + + align:start position:0% +energy State and another two in the next +highest energy State the El + + align:start position:0% +highest energy State the El + + + align:start position:0% +highest energy State the El +configuration here brillium dier one + + align:start position:0% +configuration here brillium dier one + + + align:start position:0% +configuration here brillium dier one +Sigma 1 S2 Sigma 1 + + align:start position:0% +Sigma 1 S2 Sigma 1 + + + align:start position:0% +Sigma 1 S2 Sigma 1 +sar2 Sigma 2 S2 Sigma 2 s star 2 oh the + + align:start position:0% +sar2 Sigma 2 S2 Sigma 2 s star 2 oh the + + + align:start position:0% +sar2 Sigma 2 S2 Sigma 2 s star 2 oh the +two's cut off here but there's a two + + align:start position:0% +two's cut off here but there's a two + + + align:start position:0% +two's cut off here but there's a two +okay all right what's the bond + + align:start position:0% +okay all right what's the bond + + + align:start position:0% +okay all right what's the bond +order zero there's no bond here in + + align:start position:0% +order zero there's no bond here in + + + align:start position:0% +order zero there's no bond here in +brillium two now again there is a very + + align:start position:0% +brillium two now again there is a very + + + align:start position:0% +brillium two now again there is a very +weak Bond it's 9 K per mole but for all + + align:start position:0% +weak Bond it's 9 K per mole but for all + + + align:start position:0% +weak Bond it's 9 K per mole but for all +practical purposes there is no bond + + align:start position:0% +practical purposes there is no bond + + + align:start position:0% +practical purposes there is no bond +between gillium 2 and this molecular + + align:start position:0% +between gillium 2 and this molecular + + + align:start position:0% +between gillium 2 and this molecular +orbital approach gets that + + align:start position:0% +orbital approach gets that + + + align:start position:0% +orbital approach gets that +right + + align:start position:0% +right + + + align:start position:0% +right +okay okay well NOW Boron hey boron has + + align:start position:0% +okay okay well NOW Boron hey boron has + + + align:start position:0% +okay okay well NOW Boron hey boron has +got a p electron in the atomic uh + + align:start position:0% +got a p electron in the atomic uh + + + align:start position:0% +got a p electron in the atomic uh +configuration so now what we've got to + + align:start position:0% +configuration so now what we've got to + + + align:start position:0% +configuration so now what we've got to +do is we've got to look at the + + align:start position:0% +do is we've got to look at the + + + align:start position:0% +do is we've got to look at the +constructive and destructive + + align:start position:0% +constructive and destructive + + + align:start position:0% +constructive and destructive +interference between these P wave + + align:start position:0% +interference between these P wave + + + align:start position:0% +interference between these P wave +functions all right so we got to do that + + align:start position:0% +functions all right so we got to do that + + + align:start position:0% +functions all right so we got to do that +we got to make molecular States we've + + align:start position:0% +we got to make molecular States we've + + + align:start position:0% +we got to make molecular States we've +got to let the P wve functions the P + + align:start position:0% +got to let the P wve functions the P + + + align:start position:0% +got to let the P wve functions the P +Atomic wave functions constructively and + + align:start position:0% +Atomic wave functions constructively and + + + align:start position:0% +Atomic wave functions constructively and +destructively interfere to make a new + + align:start position:0% +destructively interfere to make a new + + + align:start position:0% +destructively interfere to make a new +molecular wave function all right you + + align:start position:0% +molecular wave function all right you + + + align:start position:0% +molecular wave function all right you +ready here's how we do it here's the 2p + + align:start position:0% +ready here's how we do it here's the 2p + + + align:start position:0% +ready here's how we do it here's the 2p +X wave function or the 2p y wave + + align:start position:0% +X wave function or the 2p y wave + + + align:start position:0% +X wave function or the 2p y wave +function they look the same right one is + + align:start position:0% +function they look the same right one is + + + align:start position:0% +function they look the same right one is +just an X Dimension one is in the Y + + align:start position:0% +just an X Dimension one is in the Y + + + align:start position:0% +just an X Dimension one is in the Y +Dimension they got a noal plane right + + align:start position:0% +Dimension they got a noal plane right + + + align:start position:0% +Dimension they got a noal plane right +here all right what we're going to do is + + align:start position:0% +here all right what we're going to do is + + + align:start position:0% +here all right what we're going to do is +we're going to take that wave function + + align:start position:0% +we're going to take that wave function + + + align:start position:0% +we're going to take that wave function +over it lap it with the same wave + + align:start position:0% +over it lap it with the same wave + + + align:start position:0% +over it lap it with the same wave +function 2px or 2py from another + + align:start position:0% +function 2px or 2py from another + + + align:start position:0% +function 2px or 2py from another +atom we're going to bring these two + + align:start position:0% +atom we're going to bring these two + + + align:start position:0% +atom we're going to bring these two +within the equilibrium Bond length we're + + align:start position:0% +within the equilibrium Bond length we're + + + align:start position:0% +within the equilibrium Bond length we're +going to let this part of the wave + + align:start position:0% +going to let this part of the wave + + + align:start position:0% +going to let this part of the wave +function overlap with this part of the + + align:start position:0% +function overlap with this part of the + + + align:start position:0% +function overlap with this part of the +wave function and this part of the wave + + align:start position:0% +wave function and this part of the wave + + + align:start position:0% +wave function and this part of the wave +function overlap with this and we're + + align:start position:0% +function overlap with this and we're + + + align:start position:0% +function overlap with this and we're +going to treat constructive interference + + align:start position:0% +going to treat constructive interference + + + align:start position:0% +going to treat constructive interference +first and the result is a wave function + + align:start position:0% +first and the result is a wave function + + + align:start position:0% +first and the result is a wave function +that kind of looks like this okay in the + + align:start position:0% +that kind of looks like this okay in the + + + align:start position:0% +that kind of looks like this okay in the +center right here we got a lot of wave + + align:start position:0% +center right here we got a lot of wave + + + align:start position:0% +center right here we got a lot of wave +function because right here we have + + align:start position:0% +function because right here we have + + + align:start position:0% +function because right here we have +constructive + + align:start position:0% +constructive + + + align:start position:0% +constructive +interference in the center here we got a + + align:start position:0% +interference in the center here we got a + + + align:start position:0% +interference in the center here we got a +lot of wave + + align:start position:0% +lot of wave + + + align:start position:0% +lot of wave +function however right along the + + align:start position:0% +function however right along the + + + align:start position:0% +function however right along the +internuclear axis we got a nodal + + align:start position:0% +internuclear axis we got a nodal + + + align:start position:0% +internuclear axis we got a nodal +plane well we got a noal plane there + + align:start position:0% +plane well we got a noal plane there + + + align:start position:0% +plane well we got a noal plane there +because hey we had a noal plane in the + + align:start position:0% +because hey we had a noal plane in the + + + align:start position:0% +because hey we had a noal plane in the +atomic wave functions to begin with so + + align:start position:0% +atomic wave functions to begin with so + + + align:start position:0% +atomic wave functions to begin with so +that noal plane is maintained + + align:start position:0% + + + + align:start position:0% + +here we try this + + align:start position:0% + + + + align:start position:0% + +again + + align:start position:0% +again + + + align:start position:0% +again +okay now this molecular wave function + + align:start position:0% +okay now this molecular wave function + + + align:start position:0% +okay now this molecular wave function +here it's going to have a different name + + align:start position:0% +here it's going to have a different name + + + align:start position:0% +here it's going to have a different name +because it has a different symmetry + + align:start position:0% +because it has a different symmetry + + + align:start position:0% +because it has a different symmetry +right this way function is not + + align:start position:0% +right this way function is not + + + align:start position:0% +right this way function is not +cylindrically symmetric around the bond + + align:start position:0% +cylindrically symmetric around the bond + + + align:start position:0% +cylindrically symmetric around the bond +axis there's wave function above the + + align:start position:0% +axis there's wave function above the + + + align:start position:0% +axis there's wave function above the +bond axis and wave function below the + + align:start position:0% +bond axis and wave function below the + + + align:start position:0% +bond axis and wave function below the +bond axis right but not on the sides + + align:start position:0% +bond axis right but not on the sides + + + align:start position:0% +bond axis right but not on the sides +here it's not cylindrically symmetric so + + align:start position:0% +here it's not cylindrically symmetric so + + + align:start position:0% +here it's not cylindrically symmetric so +we got a new name for it it's a pi wave + + align:start position:0% +we got a new name for it it's a pi wave + + + align:start position:0% +we got a new name for it it's a pi wave +function and we're going to call it Pi 2 + + align:start position:0% +function and we're going to call it Pi 2 + + + align:start position:0% +function and we're going to call it Pi 2 +PX or Pi 2 + + align:start position:0% +PX or Pi 2 + + + align:start position:0% +PX or Pi 2 +py all + + align:start position:0% +py all + + + align:start position:0% +py all +right okay it's going to be a bonding + + align:start position:0% +right okay it's going to be a bonding + + + align:start position:0% +right okay it's going to be a bonding +wave + + align:start position:0% +wave + + + align:start position:0% +wave +function and of course since it's a + + align:start position:0% +function and of course since it's a + + + align:start position:0% +function and of course since it's a +bonding wave function if we look at an + + align:start position:0% +bonding wave function if we look at an + + + align:start position:0% +bonding wave function if we look at an +energy level diagram right the pi 2px + + align:start position:0% +energy level diagram right the pi 2px + + + align:start position:0% +energy level diagram right the pi 2px +and Pi 2py are going to be lower in + + align:start position:0% +and Pi 2py are going to be lower in + + + align:start position:0% +and Pi 2py are going to be lower in +energy than the atomic wave functions + + align:start position:0% +energy than the atomic wave functions + + + align:start position:0% +energy than the atomic wave functions +just like this and since the 2px and the + + align:start position:0% +just like this and since the 2px and the + + + align:start position:0% +just like this and since the 2px and the +2py in the atomic states are at the same + + align:start position:0% +2py in the atomic states are at the same + + + align:start position:0% +2py in the atomic states are at the same +energy right the pi 2px and Pi 2py hey + + align:start position:0% +energy right the pi 2px and Pi 2py hey + + + align:start position:0% +energy right the pi 2px and Pi 2py hey +they're going to be at the same energy + + align:start position:0% +they're going to be at the same energy + + + align:start position:0% +they're going to be at the same energy +in the + + align:start position:0% +in the + + + align:start position:0% +in the +molecule + + align:start position:0% +molecule + + + align:start position:0% +molecule +okay make + + align:start position:0% + + + + align:start position:0% + +sense okay let's do + + align:start position:0% +sense okay let's do + + + align:start position:0% +sense okay let's do +Boron Boron two boron has got one p + + align:start position:0% +Boron Boron two boron has got one p + + + align:start position:0% +Boron Boron two boron has got one p +electron it also has some s and uh s + + align:start position:0% +electron it also has some s and uh s + + + align:start position:0% +electron it also has some s and uh s +electrons right the S states are down + + align:start position:0% +electrons right the S states are down + + + align:start position:0% +electrons right the S states are down +here I didn't draw them in on this + + align:start position:0% +here I didn't draw them in on this + + + align:start position:0% +here I didn't draw them in on this +diagram I'm just treating right here the + + align:start position:0% +diagram I'm just treating right here the + + + align:start position:0% +diagram I'm just treating right here the +2px + + align:start position:0% +2px + + + align:start position:0% +2px +electron so what happens well what + + align:start position:0% +electron so what happens well what + + + align:start position:0% +electron so what happens well what +happens is we're going to fill each one + + align:start position:0% +happens is we're going to fill each one + + + align:start position:0% +happens is we're going to fill each one +of these states with these P + + align:start position:0% +of these states with these P + + + align:start position:0% +of these states with these P +electrons now we're going to use Hunt's + + align:start position:0% +electrons now we're going to use Hunt's + + + align:start position:0% +electrons now we're going to use Hunt's +rule again remember Hunt's rule it says + + align:start position:0% +rule again remember Hunt's rule it says + + + align:start position:0% +rule again remember Hunt's rule it says +that when you have states that are + + align:start position:0% +that when you have states that are + + + align:start position:0% +that when you have states that are +degenerate that have the same + + align:start position:0% +degenerate that have the same + + + align:start position:0% +degenerate that have the same +energy the electrons fill such that one + + align:start position:0% +energy the electrons fill such that one + + + align:start position:0% +energy the electrons fill such that one +electron goes in each state before you + + align:start position:0% +electron goes in each state before you + + + align:start position:0% +electron goes in each state before you +can put a second electron in either one + + align:start position:0% +can put a second electron in either one + + + align:start position:0% +can put a second electron in either one +of those States right so that's what we + + align:start position:0% +of those States right so that's what we + + + align:start position:0% +of those States right so that's what we +did one electron has to go here one + + align:start position:0% +did one electron has to go here one + + + align:start position:0% +did one electron has to go here one +electron has to go here you can't put + + align:start position:0% +electron has to go here you can't put + + + align:start position:0% +electron has to go here you can't put +two electrons in one of these states and + + align:start position:0% +two electrons in one of these states and + + + align:start position:0% +two electrons in one of these states and +leave the other one empty that's not the + + align:start position:0% +leave the other one empty that's not the + + + align:start position:0% +leave the other one empty that's not the +lowest energy configuration and you got + + align:start position:0% +lowest energy configuration and you got + + + align:start position:0% +lowest energy configuration and you got +to put those electrons in with parallel + + align:start position:0% +to put those electrons in with parallel + + + align:start position:0% +to put those electrons in with parallel +spins not opposite spins that's not the + + align:start position:0% +spins not opposite spins that's not the + + + align:start position:0% +spins not opposite spins that's not the +lowest energy + + align:start position:0% +lowest energy + + + align:start position:0% +lowest energy +configuration all right so that's the + + align:start position:0% +configuration all right so that's the + + + align:start position:0% +configuration all right so that's the +electron configuration here for Boron 2 + + align:start position:0% +electron configuration here for Boron 2 + + + align:start position:0% +electron configuration here for Boron 2 +one Sigma 1 S2 Sigma 1 star 2 Sigma 2 S2 + + align:start position:0% +one Sigma 1 S2 Sigma 1 star 2 Sigma 2 S2 + + + align:start position:0% +one Sigma 1 S2 Sigma 1 star 2 Sigma 2 S2 +Sigma 2 Star 2 and now Pi 2 px1 pi 2 px1 + + align:start position:0% +Sigma 2 Star 2 and now Pi 2 px1 pi 2 px1 + + + align:start position:0% +Sigma 2 Star 2 and now Pi 2 px1 pi 2 px1 +hey let's calculate the bond order here + + align:start position:0% +hey let's calculate the bond order here + + + align:start position:0% +hey let's calculate the bond order here +the bond order is 2 four five six + + align:start position:0% +the bond order is 2 four five six + + + align:start position:0% +the bond order is 2 four five six +bonding electrons two four hey four + + align:start position:0% +bonding electrons two four hey four + + + align:start position:0% +bonding electrons two four hey four +antibonding electrons 6 - 4 over 2 is 1 + + align:start position:0% +antibonding electrons 6 - 4 over 2 is 1 + + + align:start position:0% +antibonding electrons 6 - 4 over 2 is 1 +we got a single Bond 200 9 KJ per mole + + align:start position:0% +we got a single Bond 200 9 KJ per mole + + + align:start position:0% +we got a single Bond 200 9 KJ per mole +hey that's a pretty good single Bond + + align:start position:0% +hey that's a pretty good single Bond + + + align:start position:0% +hey that's a pretty good single Bond +pretty strong single Bond okay that's + + align:start position:0% +pretty strong single Bond okay that's + + + align:start position:0% +pretty strong single Bond okay that's +Boron + + align:start position:0% +Boron + + + align:start position:0% +Boron +to let's do carbon well carbon has got + + align:start position:0% +to let's do carbon well carbon has got + + + align:start position:0% +to let's do carbon well carbon has got +two 2p + + align:start position:0% +two 2p + + + align:start position:0% +two 2p +electrons so we follow the albow + + align:start position:0% +electrons so we follow the albow + + + align:start position:0% +electrons so we follow the albow +principle hey Carbon 2 all four of those + + align:start position:0% +principle hey Carbon 2 all four of those + + + align:start position:0% +principle hey Carbon 2 all four of those +electrons then are going to go into + + align:start position:0% +electrons then are going to go into + + + align:start position:0% +electrons then are going to go into +these pi 2px and Pi 2py + + align:start position:0% +these pi 2px and Pi 2py + + + align:start position:0% +these pi 2px and Pi 2py +States and here's our elect + + align:start position:0% +States and here's our elect + + + align:start position:0% +States and here's our elect +configuration we keep going here's the + + align:start position:0% +configuration we keep going here's the + + + align:start position:0% +configuration we keep going here's the +pi 2 px2 pi 2 + + align:start position:0% +pi 2 px2 pi 2 + + + align:start position:0% +pi 2 px2 pi 2 +py2 okay let's calculate the bond order + + align:start position:0% +py2 okay let's calculate the bond order + + + align:start position:0% +py2 okay let's calculate the bond order +bond order number of bonding electrons 2 + + align:start position:0% +bond order number of bonding electrons 2 + + + align:start position:0% +bond order number of bonding electrons 2 +4 6 eight bonding + + align:start position:0% +4 6 eight bonding + + + align:start position:0% +4 6 eight bonding +electrons number of anti-bonding + + align:start position:0% +electrons number of anti-bonding + + + align:start position:0% +electrons number of anti-bonding +electrons 2 4 8 - 4 is 4 / 2 bond order + + align:start position:0% +electrons 2 4 8 - 4 is 4 / 2 bond order + + + align:start position:0% +electrons 2 4 8 - 4 is 4 / 2 bond order +is two and we have a double bond right + + align:start position:0% +is two and we have a double bond right + + + align:start position:0% +is two and we have a double bond right +hey let's look and see how strong that + + align:start position:0% +hey let's look and see how strong that + + + align:start position:0% +hey let's look and see how strong that +double bond is 599 K per mole hey that's + + align:start position:0% +double bond is 599 K per mole hey that's + + + align:start position:0% +double bond is 599 K per mole hey that's +a pretty good double bond remember the + + align:start position:0% +a pretty good double bond remember the + + + align:start position:0% +a pretty good double bond remember the +double bond is shorter the double bond + + align:start position:0% +double bond is shorter the double bond + + + align:start position:0% +double bond is shorter the double bond +is stronger right our single Bonds were + + align:start position:0% +is stronger right our single Bonds were + + + align:start position:0% +is stronger right our single Bonds were +at 300 400 KJ this is almost 600 K + + align:start position:0% +at 300 400 KJ this is almost 600 K + + + align:start position:0% +at 300 400 KJ this is almost 600 K +that's a strong + + align:start position:0% +that's a strong + + + align:start position:0% +that's a strong +bond all + + align:start position:0% +bond all + + + align:start position:0% +bond all +right and this molecular orbital picture + + align:start position:0% +right and this molecular orbital picture + + + align:start position:0% +right and this molecular orbital picture +tells you that youve got this double + + align:start position:0% +tells you that youve got this double + + + align:start position:0% +tells you that youve got this double +bond here all right by virtue of this + + align:start position:0% +bond here all right by virtue of this + + + align:start position:0% +bond here all right by virtue of this +bond + + align:start position:0% + + + + align:start position:0% + +order + + align:start position:0% + + + + align:start position:0% + +yes okay uh but I'm just about to treat + + align:start position:0% +yes okay uh but I'm just about to treat + + + align:start position:0% +yes okay uh but I'm just about to treat +the 2pz all right I'll tell you what our + + align:start position:0% +the 2pz all right I'll tell you what our + + + align:start position:0% +the 2pz all right I'll tell you what our +convention is good question okay okay + + align:start position:0% +convention is good question okay okay + + + align:start position:0% +convention is good question okay okay +here comes the 2pz + + align:start position:0% + + + + align:start position:0% + +the 2 pz Atomic orbitals by + + align:start position:0% +the 2 pz Atomic orbitals by + + + align:start position:0% +the 2 pz Atomic orbitals by +convention the two pz Atomic orbitals + + align:start position:0% +convention the two pz Atomic orbitals + + + align:start position:0% +convention the two pz Atomic orbitals +we're going to + + align:start position:0% +we're going to + + + align:start position:0% +we're going to +put along the internuclear bond + + align:start position:0% +put along the internuclear bond + + + align:start position:0% +put along the internuclear bond +axis so in the case of the constructive + + align:start position:0% +axis so in the case of the constructive + + + align:start position:0% +axis so in the case of the constructive +interference of the two + + align:start position:0% +interference of the two + + + align:start position:0% +interference of the two +pz + + align:start position:0% +pz + + + align:start position:0% +pz +electrons all right in that case these + + align:start position:0% +electrons all right in that case these + + + align:start position:0% +electrons all right in that case these +two P wave functions look like this they + + align:start position:0% +two P wave functions look like this they + + + align:start position:0% +two P wave functions look like this they +were no longer coming in you know + + align:start position:0% +were no longer coming in you know + + + align:start position:0% +were no longer coming in you know +parallel to each other now they're + + align:start position:0% +parallel to each other now they're + + + align:start position:0% +parallel to each other now they're +coming in head + + align:start position:0% +coming in head + + + align:start position:0% +coming in head +on all + + align:start position:0% +on all + + + align:start position:0% +on all +right so that's our convention the 2 pz + + align:start position:0% +right so that's our convention the 2 pz + + + align:start position:0% +right so that's our convention the 2 pz +is going to be along the bond Axis Three + + align:start position:0% +is going to be along the bond Axis Three + + + align:start position:0% +is going to be along the bond Axis Three +pz is going to be along the bond + + align:start position:0% +pz is going to be along the bond + + + align:start position:0% +pz is going to be along the bond +axis all right so we're going to bring + + align:start position:0% +axis all right so we're going to bring + + + align:start position:0% +axis all right so we're going to bring +these two Atomic wave functions in we're + + align:start position:0% +these two Atomic wave functions in we're + + + align:start position:0% +these two Atomic wave functions in we're +going to let this part overlap with that + + align:start position:0% +going to let this part overlap with that + + + align:start position:0% +going to let this part overlap with that +part and the result is a wave function + + align:start position:0% +part and the result is a wave function + + + align:start position:0% +part and the result is a wave function +that looks like this lots of electron + + align:start position:0% +that looks like this lots of electron + + + align:start position:0% +that looks like this lots of electron +density or wave function right in + + align:start position:0% +density or wave function right in + + + align:start position:0% +density or wave function right in +between the two + + align:start position:0% +between the two + + + align:start position:0% +between the two +nuclei here's a node right here's a node + + align:start position:0% +nuclei here's a node right here's a node + + + align:start position:0% +nuclei here's a node right here's a node +well these are nodes because there were + + align:start position:0% +well these are nodes because there were + + + align:start position:0% +well these are nodes because there were +nodes in the atomic wave functions to + + align:start position:0% +nodes in the atomic wave functions to + + + align:start position:0% +nodes in the atomic wave functions to +begin with we're going to call this wave + + align:start position:0% +begin with we're going to call this wave + + + align:start position:0% +begin with we're going to call this wave +function the sigma 2pz it's Sigma + + align:start position:0% +function the sigma 2pz it's Sigma + + + align:start position:0% +function the sigma 2pz it's Sigma +because it's symmetric around the + + align:start position:0% +because it's symmetric around the + + + align:start position:0% +because it's symmetric around the +internuclear bond axis right so that's + + align:start position:0% +internuclear bond axis right so that's + + + align:start position:0% +internuclear bond axis right so that's +the Symmetry call that + + align:start position:0% +the Symmetry call that + + + align:start position:0% +the Symmetry call that +Sigma + + align:start position:0% +Sigma + + + align:start position:0% +Sigma +okay now what happens + + align:start position:0% +okay now what happens + + + align:start position:0% +okay now what happens +here it turns out that this Sigma state + + align:start position:0% +here it turns out that this Sigma state + + + align:start position:0% +here it turns out that this Sigma state +is a little higher in energy than the pi + + align:start position:0% +is a little higher in energy than the pi + + + align:start position:0% +is a little higher in energy than the pi +states in the next molecule there's + + align:start position:0% +states in the next molecule there's + + + align:start position:0% +states in the next molecule there's +going to be some exceptions here in a + + align:start position:0% +going to be some exceptions here in a + + + align:start position:0% +going to be some exceptions here in a +moment all right so + + align:start position:0% +moment all right so + + + align:start position:0% +moment all right so +nitrogen nitrogen has one electron in + + align:start position:0% +nitrogen nitrogen has one electron in + + + align:start position:0% +nitrogen nitrogen has one electron in +each one of the P + + align:start position:0% + + + + align:start position:0% + +States let's use the albow principle to + + align:start position:0% +States let's use the albow principle to + + + align:start position:0% +States let's use the albow principle to +fill them up well there it is two here + + align:start position:0% +fill them up well there it is two here + + + align:start position:0% +fill them up well there it is two here +two here two there right the electron + + align:start position:0% +two here two there right the electron + + + align:start position:0% +two here two there right the electron +configuration is the 1 S's and the pi 2 + + align:start position:0% +configuration is the 1 S's and the pi 2 + + + align:start position:0% +configuration is the 1 S's and the pi 2 +px2 pi 2 py2 and now Sigma 2 + + align:start position:0% + + + + align:start position:0% + +pz2 let's calculate the bond order in + + align:start position:0% +pz2 let's calculate the bond order in + + + align:start position:0% +pz2 let's calculate the bond order in +molecular nit nen well it's the number + + align:start position:0% +molecular nit nen well it's the number + + + align:start position:0% +molecular nit nen well it's the number +of bonding electrons 2 4 6 8 + + align:start position:0% +of bonding electrons 2 4 6 8 + + + align:start position:0% +of bonding electrons 2 4 6 8 +10 minus the number of antibonding + + align:start position:0% +10 minus the number of antibonding + + + align:start position:0% +10 minus the number of antibonding +electrons 2 4 10 - 4 is 6 / 2 bond order + + align:start position:0% +electrons 2 4 10 - 4 is 6 / 2 bond order + + + align:start position:0% +electrons 2 4 10 - 4 is 6 / 2 bond order +three and hey this means we got a triple + + align:start position:0% +three and hey this means we got a triple + + + align:start position:0% +three and hey this means we got a triple +bond and boy this better be a whole lot + + align:start position:0% +bond and boy this better be a whole lot + + + align:start position:0% +bond and boy this better be a whole lot +stronger and it is if you look at the + + align:start position:0% +stronger and it is if you look at the + + + align:start position:0% +stronger and it is if you look at the +bond energy in molecular nitrogen it's a + + align:start position:0% +bond energy in molecular nitrogen it's a + + + align:start position:0% +bond energy in molecular nitrogen it's a +whopping 941 + + align:start position:0% +whopping 941 + + + align:start position:0% +whopping 941 +kles per mole we got a triple bond this + + align:start position:0% +kles per mole we got a triple bond this + + + align:start position:0% +kles per mole we got a triple bond this +is a strong bond this is a short + + align:start position:0% +is a strong bond this is a short + + + align:start position:0% +is a strong bond this is a short +Bond + + align:start position:0% +Bond + + + align:start position:0% +Bond +okay okay + + align:start position:0% +okay okay + + + align:start position:0% +okay okay +now next one's going to be molecular + + align:start position:0% +now next one's going to be molecular + + + align:start position:0% +now next one's going to be molecular +oxygen and so now we've taken care of + + align:start position:0% +oxygen and so now we've taken care of + + + align:start position:0% +oxygen and so now we've taken care of +all of the wave functions the molecular + + align:start position:0% +all of the wave functions the molecular + + + align:start position:0% +all of the wave functions the molecular +wave functions that we can form from the + + align:start position:0% +wave functions that we can form from the + + + align:start position:0% +wave functions that we can form from the +2p Atomic wave functions using + + align:start position:0% +2p Atomic wave functions using + + + align:start position:0% +2p Atomic wave functions using +constructive interference it's now time + + align:start position:0% +constructive interference it's now time + + + align:start position:0% +constructive interference it's now time +to form form some molecular wave + + align:start position:0% +to form form some molecular wave + + + align:start position:0% +to form form some molecular wave +functions using destructive interference + + align:start position:0% +functions using destructive interference + + + align:start position:0% +functions using destructive interference +let's do that let's go back to 2px and + + align:start position:0% +let's do that let's go back to 2px and + + + align:start position:0% +let's do that let's go back to 2px and +2py okay they're the ones that come in + + align:start position:0% +2py okay they're the ones that come in + + + align:start position:0% +2py okay they're the ones that come in +parallel to each + + align:start position:0% + + + + align:start position:0% + +other all right so as we bring them in + + align:start position:0% +other all right so as we bring them in + + + align:start position:0% +other all right so as we bring them in +and we're going to go destructively + + align:start position:0% +and we're going to go destructively + + + align:start position:0% +and we're going to go destructively +inter we're going to do a destructive + + align:start position:0% +inter we're going to do a destructive + + + align:start position:0% +inter we're going to do a destructive +interference this part of the wave + + align:start position:0% +interference this part of the wave + + + align:start position:0% +interference this part of the wave +function is going to destructively + + align:start position:0% +function is going to destructively + + + align:start position:0% +function is going to destructively +interfere with this part this part + + align:start position:0% +interfere with this part this part + + + align:start position:0% +interfere with this part this part +constructively interferes with that part + + align:start position:0% +constructively interferes with that part + + + align:start position:0% +constructively interferes with that part +hey the result is something that looks + + align:start position:0% +hey the result is something that looks + + + align:start position:0% +hey the result is something that looks +like this we got another Mo node right + + align:start position:0% +like this we got another Mo node right + + + align:start position:0% +like this we got another Mo node right +along wrong here the + + align:start position:0% +along wrong here the + + + align:start position:0% +along wrong here the +center that's a node because of this + + align:start position:0% +center that's a node because of this + + + align:start position:0% +center that's a node because of this +destructive interference we got another + + align:start position:0% +destructive interference we got another + + + align:start position:0% +destructive interference we got another +node + + align:start position:0% +node + + + align:start position:0% +node +here where the plane of the molecular + + align:start position:0% +here where the plane of the molecular + + + align:start position:0% +here where the plane of the molecular +axis is that's because these 2p wave + + align:start position:0% +axis is that's because these 2p wave + + + align:start position:0% +axis is that's because these 2p wave +functions had nodes in them to begin + + align:start position:0% +functions had nodes in them to begin + + + align:start position:0% +functions had nodes in them to begin +with right so that's what our wave + + align:start position:0% +with right so that's what our wave + + + align:start position:0% +with right so that's what our wave +function looks like it's got some wave + + align:start position:0% +function looks like it's got some wave + + + align:start position:0% +function looks like it's got some wave +function in this quadrant and this + + align:start position:0% +function in this quadrant and this + + + align:start position:0% +function in this quadrant and this +quadrant and this quadrant and this + + align:start position:0% +quadrant and this quadrant and this + + + align:start position:0% +quadrant and this quadrant and this +quadrant this is another Pi wave + + align:start position:0% +quadrant this is another Pi wave + + + align:start position:0% +quadrant this is another Pi wave +function because it's not symmetric + + align:start position:0% +function because it's not symmetric + + + align:start position:0% +function because it's not symmetric +around this Bond + + align:start position:0% +around this Bond + + + align:start position:0% +around this Bond +axis it is a anti-bonding orbital it's + + align:start position:0% +axis it is a anti-bonding orbital it's + + + align:start position:0% +axis it is a anti-bonding orbital it's +Pi + + align:start position:0% +Pi + + + align:start position:0% +Pi +star because this was formed as a result + + align:start position:0% +star because this was formed as a result + + + align:start position:0% +star because this was formed as a result +of destructive interference so we have a + + align:start position:0% +of destructive interference so we have a + + + align:start position:0% +of destructive interference so we have a +pi star 2px and a pi star 2py let's put + + align:start position:0% +pi star 2px and a pi star 2py let's put + + + align:start position:0% +pi star 2px and a pi star 2py let's put +those on an energy level diagram if + + align:start position:0% +those on an energy level diagram if + + + align:start position:0% +those on an energy level diagram if +they're + + align:start position:0% +they're + + + align:start position:0% +they're +antibonding the energies are above those + + align:start position:0% +antibonding the energies are above those + + + align:start position:0% +antibonding the energies are above those +of the atomic States all right now let's + + align:start position:0% +of the atomic States all right now let's + + + align:start position:0% +of the atomic States all right now let's +write the electron configuration for O2 + + align:start position:0% +write the electron configuration for O2 + + + align:start position:0% +write the electron configuration for O2 +here it comes there's the four 2p + + align:start position:0% +here it comes there's the four 2p + + + align:start position:0% +here it comes there's the four 2p +electrons for each oxygen atom we're + + align:start position:0% +electrons for each oxygen atom we're + + + align:start position:0% +electrons for each oxygen atom we're +going to put two of them in the sigma 2p + + align:start position:0% +going to put two of them in the sigma 2p + + + align:start position:0% +going to put two of them in the sigma 2p +Z 2 in the pi 2p x 2 in the pi 2py and + + align:start position:0% +Z 2 in the pi 2p x 2 in the pi 2py and + + + align:start position:0% +Z 2 in the pi 2p x 2 in the pi 2py and +then we're going to f follow Hunt's Rule + + align:start position:0% +then we're going to f follow Hunt's Rule + + + align:start position:0% +then we're going to f follow Hunt's Rule +and we're going to put one electron in + + align:start position:0% +and we're going to put one electron in + + + align:start position:0% +and we're going to put one electron in +the pi star 2px and one in the pi star + + align:start position:0% +the pi star 2px and one in the pi star + + + align:start position:0% +the pi star 2px and one in the pi star +2py we didn't put them both in the pi + + align:start position:0% +2py we didn't put them both in the pi + + + align:start position:0% +2py we didn't put them both in the pi +star 2px or both in the par Pi star 2py + + align:start position:0% +star 2px or both in the par Pi star 2py + + + align:start position:0% +star 2px or both in the par Pi star 2py +and we put them in with parallel spins + + align:start position:0% +and we put them in with parallel spins + + + align:start position:0% +and we put them in with parallel spins +not opposite + + align:start position:0% +not opposite + + + align:start position:0% +not opposite +spins thank you you're going to ask me a + + align:start position:0% +spins thank you you're going to ask me a + + + align:start position:0% +spins thank you you're going to ask me a +question get to lower + + align:start position:0% +question get to lower + + + align:start position:0% +question get to lower +good question I wanted you to notice + + align:start position:0% +good question I wanted you to notice + + + align:start position:0% +good question I wanted you to notice +that hey here's a change when we get to + + align:start position:0% +that hey here's a change when we get to + + + align:start position:0% +that hey here's a change when we get to +Z equal 8 what + + align:start position:0% +Z equal 8 what + + + align:start position:0% +Z equal 8 what +happens what happens is that they want + + align:start position:0% +happens what happens is that they want + + + align:start position:0% +happens what happens is that they want +to make this tough for you and what's + + align:start position:0% +to make this tough for you and what's + + + align:start position:0% +to make this tough for you and what's +happened is that this Sigma 2pz has + + align:start position:0% +happened is that this Sigma 2pz has + + + align:start position:0% +happened is that this Sigma 2pz has +dropped in energy compared to the pi 2px + + align:start position:0% +dropped in energy compared to the pi 2px + + + align:start position:0% +dropped in energy compared to the pi 2px +and Pi 2 + + align:start position:0% +and Pi 2 + + + align:start position:0% +and Pi 2 +py at Z equal 8 the energy ordering + + align:start position:0% +py at Z equal 8 the energy ordering + + + align:start position:0% +py at Z equal 8 the energy ordering +flips at Z equal 7 for nitrogen Pi 2px + + align:start position:0% +flips at Z equal 7 for nitrogen Pi 2px + + + align:start position:0% +flips at Z equal 7 for nitrogen Pi 2px +Pi 2py is lower in energy than Sigma + + align:start position:0% +Pi 2py is lower in energy than Sigma + + + align:start position:0% +Pi 2py is lower in energy than Sigma +2pz but for Z equal 8 oxygen and + + align:start position:0% +2pz but for Z equal 8 oxygen and + + + align:start position:0% +2pz but for Z equal 8 oxygen and +above the energy ordering flips right + + align:start position:0% +above the energy ordering flips right + + + align:start position:0% +above the energy ordering flips right +Sigma is lower in energy than the pi + + align:start position:0% +Sigma is lower in energy than the pi + + + align:start position:0% +Sigma is lower in energy than the pi +that is something you have to know it + + align:start position:0% +that is something you have to know it + + + align:start position:0% +that is something you have to know it +has to do with the fact that + + align:start position:0% +has to do with the fact that + + + align:start position:0% +has to do with the fact that +the sigma 2ps has much more electron + + align:start position:0% +the sigma 2ps has much more electron + + + align:start position:0% +the sigma 2ps has much more electron +density in between the two + + align:start position:0% +density in between the two + + + align:start position:0% +density in between the two +nuclei that electron + + align:start position:0% +nuclei that electron + + + align:start position:0% +nuclei that electron +density is so high that when the nuclear + + align:start position:0% +density is so high that when the nuclear + + + align:start position:0% +density is so high that when the nuclear +charge is that of + + align:start position:0% +charge is that of + + + align:start position:0% +charge is that of +nitrogen plus 7e the nuclear charge + + align:start position:0% +nitrogen plus 7e the nuclear charge + + + align:start position:0% +nitrogen plus 7e the nuclear charge +actually isn't large enough to support + + align:start position:0% +actually isn't large enough to support + + + align:start position:0% +actually isn't large enough to support +all that electron density right but when + + align:start position:0% +all that electron density right but when + + + align:start position:0% +all that electron density right but when +you get to Z equal 8 it is and those + + align:start position:0% +you get to Z equal 8 it is and those + + + align:start position:0% +you get to Z equal 8 it is and those +energy levels FL + + align:start position:0% +energy levels FL + + + align:start position:0% +energy levels FL +it's an exception right I mean it's a + + align:start position:0% +it's an exception right I mean it's a + + + align:start position:0% +it's an exception right I mean it's a +change right there it is one that you + + align:start position:0% +change right there it is one that you + + + align:start position:0% +change right there it is one that you +have to know + + align:start position:0% +have to know + + + align:start position:0% +have to know +okay okay here's the electron + + align:start position:0% +okay okay here's the electron + + + align:start position:0% +okay okay here's the electron +configuration for molecular + + align:start position:0% +configuration for molecular + + + align:start position:0% +configuration for molecular +nitrogen if we go and we calculate here + + align:start position:0% +nitrogen if we go and we calculate here + + + align:start position:0% +nitrogen if we go and we calculate here +the bond order what will you find is the + + align:start position:0% +the bond order what will you find is the + + + align:start position:0% +the bond order what will you find is the +bond order is + + align:start position:0% +bond order is + + + align:start position:0% +bond order is +two that means we got a double bond and + + align:start position:0% +two that means we got a double bond and + + + align:start position:0% +two that means we got a double bond and +that bond strength is 494 K per mole + + align:start position:0% +that bond strength is 494 K per mole + + + align:start position:0% +that bond strength is 494 K per mole +okay so now we've got to make one more + + align:start position:0% +okay so now we've got to make one more + + + align:start position:0% +okay so now we've got to make one more +molecular + + align:start position:0% +molecular + + + align:start position:0% +molecular +orbital and that other molecular orbital + + align:start position:0% +orbital and that other molecular orbital + + + align:start position:0% +orbital and that other molecular orbital +is between the two pz states and it's + + align:start position:0% +is between the two pz states and it's + + + align:start position:0% +is between the two pz states and it's +going to be destructive + + align:start position:0% +going to be destructive + + + align:start position:0% +going to be destructive +interference so when these this part of + + align:start position:0% +interference so when these this part of + + + align:start position:0% +interference so when these this part of +the wave function overlaps with this + + align:start position:0% +the wave function overlaps with this + + + align:start position:0% +the wave function overlaps with this +part of the wave function we're going to + + align:start position:0% +part of the wave function we're going to + + + align:start position:0% +part of the wave function we're going to +cancel some wave function right and the + + align:start position:0% +cancel some wave function right and the + + + align:start position:0% +cancel some wave function right and the +result is that we're going to have a + + align:start position:0% +result is that we're going to have a + + + align:start position:0% +result is that we're going to have a +node right here in the center these are + + align:start position:0% +node right here in the center these are + + + align:start position:0% +node right here in the center these are +the two nuclei here's our nodal plane + + align:start position:0% +the two nuclei here's our nodal plane + + + align:start position:0% +the two nuclei here's our nodal plane +hey we've got a nodal plane right here + + align:start position:0% +hey we've got a nodal plane right here + + + align:start position:0% +hey we've got a nodal plane right here +anyway and one here from the atomic wave + + align:start position:0% +anyway and one here from the atomic wave + + + align:start position:0% +anyway and one here from the atomic wave +functions this wave function is a + + align:start position:0% +functions this wave function is a + + + align:start position:0% +functions this wave function is a +antibinding wave function it's Sigma + + align:start position:0% +antibinding wave function it's Sigma + + + align:start position:0% +antibinding wave function it's Sigma +star 2 + + align:start position:0% + + + + align:start position:0% + +pz and if you look at the energy level + + align:start position:0% +pz and if you look at the energy level + + + align:start position:0% +pz and if you look at the energy level +diagram its energy that antibonding + + align:start position:0% +diagram its energy that antibonding + + + align:start position:0% +diagram its energy that antibonding +state is higher in energy than Sigma Pi + + align:start position:0% +state is higher in energy than Sigma Pi + + + align:start position:0% +state is higher in energy than Sigma Pi +2 PX and Sigma Pi 2 + + align:start position:0% +2 PX and Sigma Pi 2 + + + align:start position:0% +2 PX and Sigma Pi 2 +py and so if we go to write the electron + + align:start position:0% +py and so if we go to write the electron + + + align:start position:0% +py and so if we go to write the electron +configuration for neon two well all of + + align:start position:0% +configuration for neon two well all of + + + align:start position:0% +configuration for neon two well all of +the bonding and anti-bonding states are + + align:start position:0% +the bonding and anti-bonding states are + + + align:start position:0% +the bonding and anti-bonding states are +filled the bond order in Neon 2 is zero + + align:start position:0% +filled the bond order in Neon 2 is zero + + + align:start position:0% +filled the bond order in Neon 2 is zero +right there is no bond for all practical + + align:start position:0% +right there is no bond for all practical + + + align:start position:0% +right there is no bond for all practical +purposes in Neon 2 \ No newline at end of file diff --git a/TSjJlJJ2aoI.txt b/TSjJlJJ2aoI.txt new file mode 100644 index 0000000000000000000000000000000000000000..f90ef5225f4852ac7fadb5d6dfbccb926e0c6c37 --- /dev/null +++ b/TSjJlJJ2aoI.txt @@ -0,0 +1,3206 @@ +The following +content is provided + +under a Creative +Commons license. + +Your support will help MIT +OpenCourseWare continue + +to offer high quality +educational resources for free. + +To make a donation or +view additional materials + +from hundreds of MIT courses, +visit MIT OpenCourseWare + +at ocw.mit.edu. + +PROFESSOR: And to +this purpose, we + +need to calculate +some thermodynamics. + +And we usually do that +in statistical mechanics + +by calculating for some kind +of a partition function. + +And we saw last +time that it would + +be useful to calculate this +grand partition function, which + +is the ensemble +where you specify + +the temperature, the chemical +potential, and the volume + +of the gas. + +And in this ensemble, +your task is + +to look at within +this box of volume V + +the possibility of there +being any number of particles. + +So you have to sum over all +possible N particle states. + +The contribution of +each N particle states + +is exponentially related +to the number of particles + +through the chemical potential. + +And then given that you are in +a segment that has N particles, + +you have to look at all +possible configurations + +of those particles +and integrate over + +all of those possibilities. + +And that amounts to calculating +the partition function. + +So for the partition function +of an N particle system, + +you have to integrate +over all of the momenta. + +Integration over each +component of the momentum + +gives you a factor of 1 over +lambda, where lambda again + +was related to the mass of +the particle and temperature + +through this formula +with h what we + +use to make these integrations +over pq combinations + +dimensionless. + +There are 3N such integrations. + +So that's a contribution +from the momenta. + +And then we have to +do the integration + +over all of the coordinates. + +And as long as these +particles are identical, + +we decided to divide by +the number of permutations. + +Because we cannot +tear them apart. + +So having done that, I need to +now integrate over all of the N + +particles spanning +a box of size V + +so the integration +is within the box. + +And when I have +interactions, then I + +have to worry about the +Boltzmann weight that + +comes from the interaction. + +So here I should really +put some kind of e + +to the minus beta times +the interaction U. + +And what we did was we +said that let's assume + +that this interaction comes +from pairs of particles. + +And so this U is the sum +over all possible pairs + +of particles, which +when exponentiated + +will then give you a product +over all possible pairs j, k + +and a factor that is related +to the potential interaction + +between these. + +And we found it useful +to write that factor as 1 + +plus fjk, where this fjk +stood for e to the minus + +beta of V qj minus qk minus 1. + +So basically if I +add the 1 to that, + +I just get the exponentiated +interaction potential. + +And then I have a +forum such as this. + +So basically, this +is the quantity + +that we wanted to compute. + +And so then we said, +well, let's imagine + +expanding these factors of +1 plus f1, 2, 1 plus f1, 3, + +1 plus f2, 3, all +of these factors, + +and organize them according to +the powers of f that they have. + +So the leading term would +be taking 1 from everybody. + +So that would give +me V to the N, which + +would be the 0-th +order partition + +function, the +non-interacting system. + +And then I would start +to get corrections + +where there's order of f +integrated, order of f squared + +integrated, all kinds of things. + +And that being a somewhat +difficult object to look at, + +we said, let's imagine +graphically what we would get. + +And the typical contribution +that we would get to this + +would involve having to iterate +over all of these N particles. + +So we have to somehow imagine +that we have particles 1 to N. + +And then for a particular term, +we either pick 1's-- and there + +will be some points that are +not connected to any f that is + +integrated. + +There will be a bunch of +things that will be connected + +to things where there +are pair of f's. + +There will be things +later on maybe + +where there are triplets of +f, and so forth and so on. + +And then we said that when +I do the integrations that + +correspond to this, +what do I get? + +I will get the contribution +that comes from one particle + +by itself integrated. + +Let's call that b1 +to the power of n1. + +I will get the contribution +from this pair integrated. + +I will get b2 to +the power of n2. + +I will get the contributions +from these entities. + +And in general, I said, +well, OK, somewhere in this, + +I will get bl to +the power of nl. + +Now of course, I have +a big constraint here + +that is that the +sum over l of lnl + +has to be the total +number of points 1 to n. + +So however I partition this, +I will have for each graph + +that particular +constraint acting. + +We said that clearly there's a +lot of graphs and combinations + +that give you precisely +this same factor. + +But all I had to do was +to sort of rearrange + +the numbers and +ordering, et cetera, + +and I would get all of this. + +So it would be very nice +if I could figure out + +what the overall +factor is out here. + +So we said that the factor is +something like N factorial. + +Because what I can do is I can +permute all of these numbers, + +and I would get +exactly the same thing. + +But then I have to make sure +that I don't over count. + +And not over counting +required me to divide + +by the number of +permutations that I + +have within each subgroup. + +So I have bl to the power of n. + +I have l factorial +to the power of nl. + +And then I have the change. + +Let's say this is +1, 2, this is 3, 4. + +I could have called one of +them 3, 4, the other one 1, 2. + +So basically I will have nl +factorial from the permutations + +within each. + +But I would have gotten exactly +the same numerical factor + +out front if I had +the same configuration + +but I had this diagram. + +I would have gotten +exactly the same factor. + +I would call the +contribution to this b3. + +I didn't say +currently what b3 is. + +I would have gotten +exactly the same factor. + +So maybe then what I +did was to sort of group + +all of those things +that would come + +with the same numerical factor +into this [INAUDIBLE] sum + +that I call bl. + +So I call bl to be the sum +over all l-particle clusters. + +And then, of course +here, I have to sum over + +all configurations +of nl that are + +consistent with this constraint +that I have to put up there. + +So the rest of it +then was algebra. + +We said that if I +constrain the total number, + +it's difficult for me to do. + +That's why I didn't go and +calculate the partition + +function and switch to the +grand partition function. + +Because in the grand +partition, I can essentially + +make this N that constrains +the values of these nl's + +to be all over the place. + +And therefore summing over +things with nl unconstrained + +is equivalent to summing over +terms with nl constrained, + +and then summing over whatever +the final constraint is. + +So once I did that, I was +liberated from this constraint. + +I could do the sum for each +value of nl separately. + +And the thing nicely +broke up into pieces. + +And so then what I +could do is I could + +show that each term +in the sum, there + +would be a product over +different contributions l. + +For each l, I could sum over +nl running from 0 to infinity. + +I had the 1 over nl +factorial from out here. + +I had an e to the +beta mu divided + +by lambda cubed from the +combination of these things + +raised to the +power of lnl, which + +is how big N would +have been composed. + +So I would have here lnl. + +And I also had an l factorial +raised to the power of nl. + +So I can write things +in this fashion. + +So this thing then +became the same thing + +as an exponential of a sum over +l running from 1 to infinity. + +1 over l factorial, +of if you like + +e to the beta mu over lambda +cubed to the power of l 1 + +over l factorial. + +And then I had bl. + +So it was this very nice +result somehow summing + +over all kinds of things, and +then taking the logarithm. + +The logarithm +really depends only + +on the contributions +of single clusters. + +And again, the +reason it had to be + +that way is because +the ultimate thing + +that I calculated +in this ensemble + +is that the answer +should be e to the beta V + +times the pressure. + +And so the expression that +we have over here better + +have terms which are all +proportional to volume. + +Sorry, they're all made +extensive by proportionality + +to volume. + +And indeed, when I do the +integrations over a single any + +cluster, there is one degree +of freedom, if you like, + +associated with the center +of mass of the cluster that + +can go and explore +the entire volume. + +And so all of these things are +in fact in the large end limit + +proportional to V and +something that I call bl bar. + +So once I divide by this +volume, the final outcome + +of my calculation is +that I can calculate + +the pressure of +an interacting gas + +by summing over a series whose +terms are this e to the beta mu + +over lambda cubed raised to +the power of l bl bar divided + +by l factorial. + +OK, this is correct, but not +particularly illuminating. + +Because the thing that we said +we have some intuition for + +is that the pressure +of a gas-- let's + +say if I look at it +in terms of beta P, + +actually P is the density +times kt, which is 1 over beta, + +if you like, or nkT. + +It doesn't matter. + +And then there will +be corrections. + +There will be a term that +is order of n squared. + +There will be a term +that is order of n cubed. + +And there are +these coefficients, + +which are functions +of temperature, + +that are called the +virial coefficient. + +And this is a virial expansion. + +Essentially what +it is is a fitting + +of the form of the +pressure of the gas + +as a function of density. + +In the very low density limit +you get ideal gas result. + +And presumably because +of these interactions, + +you will get corrections +that presumably also + +know about the +potential that went + +into the construction of all +of these b bars, et cetera. + +So how do we relate these things +that are, say, experimentally + +accessible to this expansion +that we have over here? + +And the reason it is +not obvious immediately + +is because this is an expansion +in chemical potential, + +whereas over here, +I have density. + +So what do I do? + +Well, I realize that the density +can be obtained as follows. + +In the grand canonical ensemble, +the number of particles + +is in principal a +random variable. + +But that random variable +is governed by this e + +to the beta mu N that +controls how many you have. + +And if I take the log of +Q with respect to beta mu, + +I will generate +the average number, + +which in the +thermodynamic limit we + +expect to be the same thing +as what we thermodynamically + +would call the number. + +And this log Q we just +established is beta PV. + +So what we have here is +the derivative of beta VP + +with respect to beta mu. + +And if I do this at +constant temperature, + +the betas disappear. + +This is the same +thing as V dP by d + +mu at constant temperature. + +But also I can take the +derivative right here. + +So what happens? + +I will find that the +density which is N over V, + +is the derivative of this +expression with respect + +to beta mu. + +I go and I find that +there's a beta mu. + +If I take a derivative of +this with respect to beta mu, + +really it's exponential +of beta mu l. + +The derivative of it will +give me l e to the beta mu l. + +So what I get is a sum +over l e to the beta mu + +over lambda cubed. + +l gets repeated. + +And then I will +have l times this. + +So I will have vl bar divided +by l minus 1 factorial. + +So the series for +density is very + +much like the +series for pressure, + +except that you replace 1 +over l factorial with 1 over l + +minus 1 factorial. + +So now my task is clear. + +What I should do +is I should solve + +given a particular +density for what mu is. + +Once I have mu as a +function of density, + +I can substitute it back here. + +And I will have pressure +as a function of density. + +Of course it's clear that +the right variable to look at + +is not mu, but x, which is e to +the beta mu over lambda cubed. + +This actually has a name. + +It's sometimes called fugacity. + +So the second +equation is telling me + +that the density I can write in +terms of the fugacity as a sum + +over l x to the l bl bar divided +by l minus 1 factorial, which + +if I were to sort of +write in its full details, + +it starts with b1 bar x +plus b2 bar x squared. + +Because there I have 0 factorial +or 1 factorial respectively. + +The next term will be +b3 bar over 2 x cubed. + +And this will go on and on. + +Also, let me remind +you what b1 bar is. + +b1 bar, for every +one of these b1 bars, + +I have to divide by 1 +over V because of this V. + +And then I have to do the +integration that corresponds + +to the one cluster, which is +essentially one cluster going + +over the entirety of space, +which will give me V. + +So this is in fact 1. + +So basically this +coefficient here is 1. + +And then I will have +the corrections. + +So you say, well, I have +n as a function of x. + +I want x as a function of n. + +And I say, OK, that's +not that difficult. + +I will write that x +equals n minus b2 bar + +x squared minus b3 bar x +cubed over 2, and so forth. + +And I have now x. + +Maybe a few of +you are skeptical. + +Some of you don't +seem to be bothered. + +OK, so my claim is +that this is indeed + +a systematic way of solving +a series in which when + +the density goes to 0, you +expect x to also go to 0. + +And to lowest order, x will +be of the order of density. + +And these will be higher +order powers in density. + +So to get a systematic series +in density, all you need to do + +is to sort of work with a +series such as this keeping + +in mind what order you +have solved things to. + +So I claim that to +lowest order, this really + +just says that x is n. + +And then there are corrections +that are order of n squared. + +And to get the next order +term, all I need to do + +is to substitute the lower +order in this equation. + +So basically if I substitute +x equals n in this equation, + +I will get n minus b2 n square. + +If I substitute x over n here, +it will be a higher order term. + +And I claim that this +is the correct result + +to order of n cubed. + +And then to get the +result to order of n + +cubed, I substitute this back +into the original equation. + +So I start with n minus +b2 bar, the square + +of the previous solution +at the right order. + +So squaring this, I will +get n squared minus twice + +b2 bar n cubed. + +And the next term that would +be the square of this, which + +is order of n to the +fourth, I don't write down. + +And then I have +minus b3 bar over 2, + +the cube of the +previous solution. + +And at the right +order that I have, + +that's the same thing +as b3 bar over 2 n cubed + +and order of n to the fourth. + +And all I really need +to do at this order + +is to recognize that +I have two terms that + +are order of n cubed. + +Putting them together, I have +n minus b2 bar n squared. + +And then I have +plus 2b2 bar squared + +minus b3 bar over 2 n cubed +and order of n to the fourth. + +So now we erase this. + +OK, so now I have solved for +x in a power series in n. + +All I need to do +is to substitute + +in the power series for p. + +So let's write that down. + +The power series for +beta p is b1 bar times + +the density b2 bar +squared over 2 density + +square, b3 bar over +3 factorial, which + +is 6 n cubed, and so forth. + +But I only calculated +things to order of n cubed. + +Also, b1 bar is the +same thing as 1. + +So basically that's what +I should be working with. + +And so all I need to do +is to substitute-- oops, + +except that these are all x's. + +The series here +for beta p that I + +have is in powers +of this quantity x. + +And it is x that I had +calculated as a function of n. + +To the order that I calculated, +it is n minus b2n squared. + +And then I have 2b2 +squared minus b3 over b3. + +Somehow this sounds +incorrect to me. + +Nope, that's fine. + +Because here I have 2. + +So that's correct. + +b3 over 2 n cubed-- +so essentially, + +I just substituted for x here. + +The next order +term is going to be + +b2 over 2 times the square of x. + +The square of x will give +me a term that is n squared, + +a term that is from +here 2b2n cubed. + +Order of n to the fourth I +haven't calculated correctly. + +Order of n cubed +I have b3 over 6. + +And just x cubed is the same +thing as n cubed to this order. + +And I have not calculated +anything at the next order. + +So let's see what we have. + +We have n. + +At the next order, there are +two terms that are n squared. + +There is this term, +and there is that term. + +Putting them together, I will +get minus b2 over 2 n squared. + +At the next order, at +the order of n cubed, + +I have a bunch of terms. + +First of all, there +is this 2b2 squared. + +But then multiplying this with +this will subtract one b2. + +So I'm going to be +left with b2 squared. + +And then I have minus 1/2 b3. + +So that's one term. + +And then I have plus 1/6 b3. + +Minus 1/2 plus 1/6 is minus 1/3. + +So this is minus +b3 over 3 n cubed. + +And I haven't calculated +order of n to the fourth. + +And this is the formula for BP. + +So lowest order, I have +the ideal gas result. + +Actually, let me, +for simplicity, + +define the virial +coefficients in this fashion. + +The second order, I will +get a correction B2, + +which is minus 1/2 of b2 bar. + +So this is minus 1/2 +of the diagram that + +corresponds to essentially +one of these lines + +that I have up here. + +And so what is it? + +It is minus 1/2 the integral +over the relative coordinate + +of e to the minus +beta v as a function + +of the relative +coordinate minus 1. + +Now earlier, we had in fact +calculated this result directly + +through the partition function. + +I did a calculation in which +I calculated the first term + +in the other way of +looking at things, + +in the cumulant expansion, +as a function of expansions + +in the potential. + +We saw that there +was a term that all + +was order of density squared. + +We summed all of the +terms to get this factor. + +And there was precisely +a factor of minus 1/2 + +as a correction to +pressure once we + +took the derivative of +the partition function + +with respect to volume. + +OK, so the thing that is new is +really the next order term, B3, + +which is b2 squared +minus b3 bar over 3. + +OK, so what is that? + +Diagrammatically, +B2 was this factor + +that we calculated above and +is the square of this pair. + +And then I have to subtract +from that 1/3 of whatever + +goes into B3. + +Now remember, we said that B3, +I have to pick three points + +and make sure I link them +in all possible ways. + +So the diagrams that go into +B3, one of them is this. + +But then there are +three other ways + +of making a linked object, +which is these things. + +We also saw that if +I were to calculate + +the contribution of any +one of these objects, + +I can very easily choose +to measure my coordinates + +with respect to, say, the +point that is at their apex. + +And then I would +have one variable + +which is this distance, +one variable which + +is that distance. + +And independently, +each one of them + +would give me the factor +that I calculated before. + +In essence, all of these one +particle reducible graphs + +give a contribution, +which is the product + +of these single line graphs. + +There are three of them. + +Minus 1/3 precisely +cancels that. + +And so the calculation that +goes into the third virial + +coefficient ultimately will +only depend on this one graph. + +And we had anticipated +this before. + +When we were doing +things previously + +using the expansion of +the partition function, + +we saw that in this +cumulant expansion, + +only the cumulants +were appearing. + +And for calculation +of the cumulants, + +I had to do lots +of subtractions. + +And those subtractions +were genetically + +removing these one +particle reducible graphs. + +And this continues +to all orders. + +And the general formula is +that the l-th contribution here + +will be a factor of l minus 1 +over l factorial, which is not + +so difficult to get by +following the procedures + +that I have described over here, +and then the part of bl that + +is one particle irreducible. + +So this is the +eventual result for how + +you would be able, given some +particular form of the two body + +interaction, to calculate +an expansion for pressure + +in powers of density, how the +coefficients of that expansion + +are related to properties +of this potential + +through this +diagrammatic expansion. + +So this is formally correct. + +And then the next question +is, is it practical? + +Is it useful? + +So we need to start computing +things to see something + +about the usefulness of this +series for some particular type + +of potential. + +So we are going to look +at the kind of potential + +that I already +described for you. + +That is, if I look at two +particles in a gas that + +are separated by +an amount r-- let's + +imagine the potential +only depends + +on the relative distance, not +orientation or anything else. + +We said that basically, +at large distances, + +the potential is attractive +because of van der Waals. + +At short distances, the +potential is repulsive. + +And so you have a general +form such as this. + +Now, if I want to +do calculations, + +it would be useful for +me to have something + +that I can do +calculations exactly + +with and get an estimate. + +So what I'm going to do is +to replace that potential, + +essentially, with a hard wall. + +So my approximation to the +potential is that my v of r + +is infinite for +distances, separations + +that are less than some r0. + +So basically, I define +some kind of r0, + +which is the-- if you think +of them as billiard balls, + +it's related to the closest +distance of approach. + +This potential at +large distances + +has typical van der +Waals form, by which + +I mean it falls off as +a function of separation + +with the sixth power. + +It is attractive. + +So I put a minus sign here. + +In order to make sure that I +get eventually the dimensions + +right, the coefficient that goes +here I write as r0 with a u0 + +up here such that if I assume +that the potential is precisely + +this for all r that are +greater than r0, then + +I'm replacing the +actual potential + +by something like this. + +And the minimum +depth of potential + +will occur at this cusp +over here at minus u0. + +So why did I do that? + +Because now I can +calculate with that + +what the second +virial coefficient is. + +So what is B2? + +B2 is minus 1/2 the integral +of relative potential. + +Now this integral +will take two parts + +from these two +different contributions. + +One part is when I'm in the +regime where the particles are + +excluded, the +potential is infinity. + +And there, f is simply minus 1. + +So that minus 1 then gets +integrated from 0 to r, + +giving me the volume +that is excluded. + +So what I will get +here is a minus 1 + +times the excluded volume. + +That's the first part, where +the volume is, of course, + +4 pi over 3 r0 cubed for +the volume of the sphere. + +And then I have to +add the part where + +I go from f0 all +the way to infinity. + +The potential is +vertically symmetric. + +So d cubed r becomes +4 pi r squared dr. + +And I have to integrate +e to the minus + +beta times the attractive +part of the potential. + +So it's beta u0 r0 over +r to the sixth minus 1. + +So what I will do, +I will additionally + +assume that I'm in the +range of parameters + +where this beta u0 +is much less than 1, + +that is, at temperatures +that are higher + +compared to the depth of +this potential converted + +to units of kT. + +And if that is the case, +then I can expand this. + +And the expansion +to the lowest order + +will simply give me beta u0 +r0 over r to the sixth power. + +And I will ignore +higher order terms. + +So this, if you like, is +order of beta u0 squared. + +Now, having done that, then the +second integral becomes simple. + +Because I have to +integrate r squared + +divided by r to the fourth, +which is r to the minus 4. + +Integral of r to the minus +4 gives me r to the minus 3. + +And then there's a factor of +minus 1/3 from the integration. + +It has to be evaluated +between 0 and infinity. + +And so the final answer, +then, for B2 is minus 1/2. + +I have minus 4 pi over 3 r0 +cubed from the excluded volume + +part. + +From here, I will get a 4 +pi beta u0 r0 to the sixth. + +And then I will get this +factor of r the minus 3 + +over 3 evaluated +between infinity, + +which gives me 0 and r0. + +So you can see that with +this potential, actually + +both terms are proportional +to 4 pi r0 cubed over 3. + +And so I can write the +answer as minus omega over 2 + +where I have defined omega +to be this 4 pi r0 cubed + +over 3, which is +the excluded volume. + +Basically, it's the volume that +is excluded from exploration + +when you have two particles. + +Because their center of mass +cannot come as close as r0. + +So that 1/2 appears here as 1. + +Because I already +took care of that. + +This rest of the coefficients +are proportional to this + +except with a factor +of minus beta u0. + +So I get minus beta u0. + +So this is your second +virial coefficient for this. + +AUDIENCE: It should +be positive out front. + +PROFESSOR: Pardon? + +AUDIENCE: It should be positive +out front, [INAUDIBLE]? + +PROFESSOR: Yes, because +there was a minus, + +and there's a minus. + +There's a plus. + +Let's keep that. + +So what we have +so far, we've said + +that beta times the pressure +starts with ideal gas behavior + +n. + +And then I have the +next correction, + +which is this B2 +multiplying n squared. + +So I will have n squared +times this coefficient + +that I have calculated for +this type of gas, which + +is omega over 2 1 minus beta u0. + +And presumably there are +higher order terms in this. + +So whenever you see +something like this, + +then you have to +start thinking about, + +is this a good expansion? + +So let's think about +how this expansion could + +have become problematic. + +Actually, there is already one +thing that I should have noted + +and I didn't, which is short +versus long range potential. + +Now, it was nice +for this potential + +that I got an answer +that was in the form + +that I could write +down, factor out omega. + +You can say, well, +would you have always + +been able to do something +similar to that? + +Because you see, +ultimately what this + +says is that in order for all +of these terms in this expansion + +to be dimensionally correct, +the next term is a density, + +has dimensions of +inverse volume, + +density squared +compared to this. + +So it should be compensated +by some factor of volume. + +And we can see that +this factor of volume + +came from something +that was of the order + +of this size of the +molecule, this r0. + +OK, so it's interesting. + +It says that it's really +the short-range part + +of the potential that seems +to be setting the correction. + +Now, where did that come from? + +Well, there was one +place that I had + +to do an integration +over the potential. + +And I found that +the integration was + +dominated by the lower range. + +That was over here. + +Where would this +become difficult? + +AUDIENCE: In a small box? + +PROFESSOR: In a +small box, but we + +are always taking the +thermodynamic limit + +where V goes to infinity. + +AUDIENCE: Or inverse square log? + +PROFESSOR: Inverse square +log, yes, that's right. + +So who says that this +integral should converge? + +I'm doing an integral d cubed +r, something like v of r. + +And convergence was the +reason why this integral + +was dominated by short distance. + +If this potential goes +like 1 over r cubed, + +then it will logarithmically +depend on the size of the box. + +For Coulomb interaction, +1/r potential + +you can't even think about it. + +It's just too divergent. + +So this expansion will +fail for potentials + +that have tails that +are decaying as 1 + +over r cubed or even slower. + +Fortunately, that's not +the case for van der Waals' + +potential and +typical potentials. + +But if you have a plasma, +you have to worry about this. + +And that's why I was +also saying last time + +that the typical expansions +that you have to do for plasmas + +are different. + +So given that we are +dominated by the short range, + +what is the correction +that I've obtained + +compared to the first term? + +So essentially, I have +calculated a second order term + +that is of the order of this +divided by the first order + +term and pressure +that was density. + +And we find that this is +of the order of n omega. + +How many particles are within +the range of interaction? + +And this would be +kind of like the ratio + +of the density of liquid +to the density of gas. + +Because the density of +liquid would be related-- oh, + +it's the other way around. + +The density of liquid +would be 1 over the volume + +that one particle occupies. + +So the density of liquid +would go in the denominator. + +The density of gas is this +n that I have over here. + +And again, for the +gas in this room, + +this ratio is of the order +of 10 to the minus 3. + +And we are safe. + +But if I were to +start compressing this + +so that I go to higher +and higher densities, + +ultimately I say that this +second order term becomes + +of the order of the +first order term. + +And then perturbation +doesn't make sense. + +Naturally, the reason for +that is I haven't calculated. + +But typically what you +find is that if you + +go to higher and +higher order terms + +in the series, in most cases, +but clearly not in all cases, + +the ratio of successive +terms is more or less + +set by the ratio +of the first terms. + +It has to be +dimensionally correct. + +And we've established that +the typical dimension that + +is controlling everything is +the volume of the particle. + +So this expansion will fail +for long range potentials, + +for going to +liquid-like densities. + +But also I made +another thing, which + +is that I assumed that that +could expand this exponential. + +And then in principle, +there are other difficulties + +that could arise if this +condition that I wrote here + +is violated. + +If beta u0 is greater than 1, +then this coefficient by itself + +becomes large exponentially. + +And then you would expect that +higher order terms will also + +get more factors of this +exponential and potential. + +And things will blow up on you. + +So it will also +have difficulties + +at low temperatures for +attractive potentials. + +Again, the reason +for that is obvious. + +If you have an +attractive potential, + +you go to low +enough temperature, + +and the ground state is +everybody sticking together-- + +looks nothing like a gas, looks +like a solid or something. + +So these are the +kind of limitations + +that one has in this series. + +OK, let's be brave +and do some more + +rearrangements of this equation. + +So I have that to +this order, beta P + +is n plus n squared +this excluded + +volume over 2 1 minus beta u0. + +And then there's higher +order terms of course. + +And then I notice that there are +two terms on this equation that + +are proportional to beta. + +And I say, why not put +both of them together? + +So I will have beta. + +Bring that term to +this side, and it + +becomes P plus n +squared omega over 2 u0. + +And then what is left +on the other side? + +Let's factor out the n. + +I expect this to be a series in +higher and higher powers of n. + +And the first +correction to 1 comes + +from here, which +is n omega over 2. + +And I expect there to +be higher order terms. + +Now again, to order of n squared +that I have calculated things + +correctly, this +expression is no different + +from the following expression-- +1 minus n omega over 2. + +Again, there will be +higher order terms in n. + +But the order of n squared, +both of these equations, + +expressions, are equivalent. + +So if I now ignore +higher order terms, + +this whole thing is equivalent +to P plus n squared u-- + +well, let's write this in +the following fashion-- p + +plus u0 omega over 2 N over +V, which is density squared. + +And actually this side, if +I were to multiply by V, + +what do I get? + +This becomes numerator +V, denominator V minus N + +omega over 2. + +Let's multiply by V +minus N omega over 2. + +And the right-hand +side will be-- + +AUDIENCE: Is that where +it should be there? + +PROFESSOR: What happened? + +AUDIENCE: This one, [INAUDIBLE]. + +PROFESSOR: Yes, so if I multiply +this, which is N over V, by V, + +I will get N, +good, which removes + +the difficulty that I had. + +Because now I multiply by kT. + +And the left hand +side disappears. + +And on the right hand +side, I will get NkT. + +So we'll spend some +time on this equation + +that you will likely recognize +as the van der Waals equation. + +I kind of justify it by +rearranging this series. + +But van der Waals +himself, of course, + +had a different way +of justifying it, + +which is that basically if +we think about the ideal gas, + +and you have particles that are +moving within some volume V, + +if you have excluded +volume interactions, + +then some of this volume +is no longer available. + +And so maybe what +you should do is + +you should reduce the +volume by an amount that + +is proportional to the +number of particles. + +This factor of 1/2 is +actually very interesting. + +Because it is correct. + +And I see that a +number of people + +in well known +journals, et cetera, + +write that the excluded +volume should be essentially + +n times the volume that is +excluded around each particle. + +It's not that. + +It is 1/2 of that. + +And I'll leave you +to mull on that. + +Because we will +justify it later on. + +But in the meantime, +you can think + +about why the factor +of 1/2 is there. + +The other issue +is that-- so there + +has to be a correction +to the volume. + +And the kind of +hand-waving statement + +that you make about the +correction to pressure + +is that if you think about the +particle that is in the middle, + +it is being attracted by +everybody, whereas when + +it comes to the surface, it +is really being attracted + +by things that are +half of the space. + +So there is an +effective potential + +that the particles feel +from the collective action + +of all the others, which +is slightly less steep when + +you approach the boundaries. + +And therefore, you can either +think that because of this, + +there's less density that +you have at the boundary. + +Less density will give +you less pressure. + +Or if you have a +particle that is + +kind of moving +towards the wall, it + +is being pulled +back so it doesn't + +hit the wall as strongly +as you would expect, + +that would give the +pressure of the ideal gas. + +So there is a pressure that +has to be reduced related + +to the strength of the +potential and something that + +has to do with all of +the other particles. + +And there's density +squared will appear there. + +We will have a more full +justification of this equation + +later on. + +But for the time being, let's +sort of sit with this equation + +and think about its +consequences for awhile. + +Because the thing that +we would like to do + +is we have come from a +perspective of looking + +at the ideal gas and how the +pressure of the ideal gas + +starts to get corrected +because of the interactions. + +Of course, things +become interesting + +when you go to the dense limit. + +And then the gas becomes +something like a liquid. + +And you have transitions +and things like that. + +So really, it's the other limit, +the dense, highly interacting + +limited that is interesting. + +And to get that, we +have few choices. + +Either I have to somehow sum +many, many terms in the series, + +which will be very difficult, +and we can't do that, + +or you can make some kind of +approximation, rearrangement, + +and a guess. + +And this is what the van der +Waals equation is based on. + +I made the guess here +by somewhat rearranging + +and re-summing the +terms in this series. + +But I will give you shortly +a different justification + +that is more transparent +and tells you immediately + +what the limitations are. + +But basically that's +why we are going + +to spend some time +with this equation. + +Because ultimately, we +are hoping to transition + +from the weakly interacting +case to the strongly interacting + +case. + +Yes. + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: No, no, +no, no, omega was + +defined as the volume +excluded around one particle. + +So if you're thinking +about billiard balls, + +r0 is the diameter. + +It's not the radius. + +And 4 pi over 3 r0 cubed +is 8 times the diameter + +of a single billiard ball. + +So the correction that +we get, if you like, + +is 4 times the volume of +a billiard ball multiplied + +by the number of billiard balls. + +Where was I? + +OK, so what this equation +gives you, the van der Waals, + +is an expression for +how the pressure behaves + +as a function of volume. + +Actually, it would be nicer +if we were to sort of replace + +this by volume per +particle, which + +would be the inverse density. + +But you can use +one or the other. + +It doesn't matter. + +Now, what you find is +that there is, first + +of all, a limitation +to the volume. + +So basically, none +of your cares are + +going to go to volumes that +are lower than n omega over 2. + +So basically there's a barrier +here that occurs over here. + +But if you go to +the other limit, + +where you go to large volumes, +you can ignore terms like this. + +And then you get back the +kind of ideal gas behavior. + +So basically, in +one limit, where + +you are either at +high temperatures-- + +and at high temperatures, +essentially, the correction + +here will also be negligible. + +Or you are at high +values of the volume. + +You get isotherms that are +very much like the isotherms + +that you have for the +ideal gas, except that + +rather than asymptote +to 0, PV going like NkT, + +you asymptote to +this excluded volume. + +So this is for high T, T large. + +T larger than what? + +Well essentially, +what happens is + +that if I look at the pressure, +I can write it in this fashion + +also. + +It is NkT divided by V +minus N omega over 2. + +So that's the term that +dominates at high temperature. + +It's proportional to kT. + +But then there's the subtraction +u0 omega over 2 N/V squared. + +And again, this term is not +so important at large volume. + +Because at large +volume, this 1/V + +is more dominant than +1 over V squared. + +But as you go to +lower temperatures + +and intermediate volumes, +then essentially you + +have potentially a correction +that falls off as minus 1 + +over V squared. + +And so this correction that +falls off as 1 over V squared + +can potentially +modify your curve, + +bring it down, and then give +it a structure such as this. + +So this is T less than. + +And clearly, between these +two types of behavior, + +where there is +monotonic behavior + +or non-monotonic +behavior, there has + +to be a limiting curve that, +let's say, does something + +like this, comes tangentially +to the horizontal axis, + +and then goes on like this. + +So this would be +for T equals Tc. + +This is T greater than +Tc, T less than Tc. + +OK, so that's fine, +except that now we + +have encountered the difficulty. + +Because one of the things +that we had established + +for thermodynamic stability +was that delta P delta + +V had to be negative. + +And the ideal gas +curve and portions + +of this curve which +have a negative slope + +are all consistent with this. + +But this portion over here +where dP by dV is positive, + +it kind of violates +the condition + +that the compressibility +kappa T, which is minus 1/V dV + +by dP at constant temperature, +better be positive. + +And so clearly, the expression +that one gets through this van + +der Waals equation +has a limitation. + +And the most +natural way about it + +is to say, well, the +question that you wrote down + +is clearly incorrect. + +That's certainly true. + +Also, this equation +is incorrect, + +except that this +kind of reminds us + +with what actually happens if I +look at the isotherms of a gas, + +such as gas in this +room, or something that + +is more familiar, such as water. + +What you find is that +at high temperatures, + +you indeed have curves +that look like this. + +But at low temperatures, +you liquidify. + +And what you have is +a zone of coexistence, + +let's say something +like this, by which I + +mean that the +isotherm that you draw + +has a portion that +lives in the gas phase + +and is a slightly modified +version of the ideal gas. + +But then it has a +portion that corresponds + +to the more or less +incompressible liquid. + +Although this has clearly still +some finite compressibility. + +And then in between, there is a +region where if you have a box, + +part of your box would be +liquid, and part of your box + +would be gas. + +And as you compress the box, +the proportion of liquid and gas + +will change. + +And this happens for +T less than some Tc. + +And once more, there +is a curve that kind of + +looks like this at some +intermediate temperature Tc. + +So you look at the +comparison, you say, well, + +as long as I stay +above Tc-- of course + +I don't expect this equation +to give the right numbers + +for what Tc or whatever is. + +But qualitatively, I get +topologies and behaviors + +at that T greater +than Tc all the way up + +to Tc are not very different. + +But at T less than +Tc, they also signal + +that something bad is happening. + +And somehow, the original +description has to be modified. + +And so the thing that Maxwell +and van der Waals and company + +did was to somehow convert +this incorrect set of equations + +to something that +resembles this. + +So let's see how they +managed to do this. + +Actually, this may not be a +bad thing to keep in mind. + +Let's have a +thermodynamic-- well, + +I kind of emphasize that there +is thermodynamic reason for why + +this is not valid. + +Always there's a +corresponding reason + +if you look at things +from the perspective + +of statistical mechanics. + +So it may be useful +to sort of think + +about what's happening +from that perspective. + +Let's imagine that we are in +this grand canonical ensemble. + +In the grand canonical ensemble, +the number of particles, + +as we discussed, is not fixed. + +But the mean number of particles +is given by the expressions + +that we saw over +here, is related + +to the pressure through dP by +d mu at constant temperature. + +But there are fluctuations. + +So you would say that the +fluctuations are related + +by taking a second +derivative of this object. + +Because clearly, q, if I were to +expand it in powers of beta mu, + +will generate +various moments of n. + +Log of q will +generate cumulants. + +So the variance would +be one more derivative. + +And so that will +amount to taking + +a derivative of the +first derivative, which + +was the number itself. + +So I will get this to be +dN by d mu at constant T, + +except that there's an +additional factor of kT. + +So maybe I will write +this carefully enough. + +I have d2 log Q with +respect to beta mu squared + +will give me N squared. + +Now, the first derivative with +respect to beta mu of log Q + +gave me the mean, which I'm +actually thinking of as N + +itself. + +And then there's +this factor of beta. + +So this is really kT dN by d mu. + +All of these are done +at constant temperature. + +So the statistical +analog of stability + +really comes down to +variances being positive. + +So my claim is that this +variance being positive + +is related to this +stability condition. + +Let me do that in the +following fashion. + +I divide these two expressions. + +I will get the average +of N squared divided + +by average of N, which is really +N, so the variance over N. + +I have kT. + +And then I have the ratio +of two of these derivatives. + +And the reason I +wanted to do that ratio + +was to get rid of the d mu. + +Because d mu is not so nice. + +If I take the ratio of +those two derivatives, + +I will get dN by +dP at constant T. + +But what I really wanted was +to say something about dV + +by dP at constant T +rather than dN by dP. + +So what I'm going to do is to +somehow convert this dN by dP + +into dN by dV, +and then dV by dP. + +And actually to do that, I +need to use the chain rule. + +So this will be T, +P. This will be T, N. + +And the chain rule will give +me an additional minus sign. + +So this is a reminder of +how your partial derivatives + +and the chain rule goes. + +Finally, dN by dV is none +other than the density N/V. + +At constant temperature, N +and V will be proportional. + +And what I have here +is 1/V dV by dP, + +which is the compressibility. + +So the whole thing here +is NkT times kappa of T. + +And so this being positive, +this positivity of the variance, + +is-- the thermodynamic +analog of it + +was from the stability, +and something such as this. + +The statistical analog of +it is that the probability + +distribution that I'm looking at +in the grand canonical ensemble + +as a function of N has to be +peaked around some region. + +The variance around +that peak better + +be positive so that I'm looking +in the vicinity of a maximum. + +If it was negative, +it means that I'm + +looking in the +vicinity of a minimum. + +And I'm looking at the +least likely configuration. + +So it cannot be allowed. + +So that's the +statistical reason. + +OK, now I want to use +that in connection + +with what we have +over here and see + +what I can learn about this. + +I said that I wrote two +expressions and divided them, + +because I didn't want to deal +with the chemical potential. + +But let me redefine that +and say the following, + +that N is V dP by +d mu at constant T. + +And maybe I will start to +gain some idea about chemical + +potential if I +rearrange this as d mu + +is V/N dP along this surface +of constant P at constant T. + +And then I can calculate +mu as a function of P + +at some particular +temperature minus mu + +at some reference point by +integrating from the reference + +point to the +pressure of interest + +the quantity V/N dP prime +where V of P prime I + +take from this curve. + +So this curve gives me +P as a function of V. + +But I can invert it and think +of V as a function of P, + +put it here, and see what is +happening with the chemical + +potential if I walk along +one of these trajectories. + +And in particular, let's +kind of draw one of these + +curves that I am +unhappy with that + +have this kind of +form in general + +and calculate what happens +to the chemical potential + +if I, let's say, pick +this reference point + +A, and the corresponding +pressure PA, + +and go along this curve, which +corresponds to some temperature + +T that is less than this +instability temperature, + +and track the shape of +the chemical potential. + +So this formula says that the +change in chemical potential we + +obtained by calculating +V-- divide by N, + +but our N is fixed-- +as a function of P, + +and integrating as +you go up in pressure. + +So essentially, I'm calculating +the integral starting + +from point A as I +go under this curve. + +So let's plot as a result +of that integration how + +that chemical potential at +P minus PA is going to look + +like as I go in P beyond PA. + +So at PA, that's my reference. + +The chemical potential +is some value. + +As I go up and up, because +of this area of this curve, + +I keep adding to the +chemical potential + +until I reach the maximum +here at this point C. + +So there is some curve that goes +from this A to some point C. + +Now, the thing is that when I +continue going along this curve + +down this potential all the way +to the bottom of this, which + +I will call D, my +DP's are negative. + +So I start subtracting +from what I had before. + +And so then the curve +starts to go down. + +So all the way to +D, I'm proceeding + +in the opposite direction. + +Once I hit D, I start going all +the way to the end of the curve + +however far I want to go. + +And I'm adding +some positive area. + +So the next part I also have a +variation in chemical potential + +that goes like this. + +So you ask, well, if I give +you what the temperature is + +and what the pressure +is-- and I have told you + +what the temperature +and pressure are-- + +I should be able to calculate +the chemical potential. + +It's an intensive +function of the other two + +intensive functions. + +And this curve tells me +that, except that there + +are regions where I don't +know which one to pick. + +There are regions where +it's obvious there's + +one value of the +chemical potential. + +But there is in between, +because of this instability, + +three possible values. + +And typically, if +you have systems-- + +think about different chemicals +that can go between each other. + +And there are potentials for +chemical transformations. + +You say, go and pick the +lowest chemical potential. + +The system will evolve +onto the condition that + +has the lowest +chemical potential. + +So that says that when you +have a situation such as this, + +you really have to +pick the lowest one. + +And so you have to bail out on +your first curve at the point + +B, and on your second curve at +a point E, where on this curve + +B and E are such that when +you integrate this BDP all + +the way from B to E, you will +get 0, which means that you + +have to find points B and E +such that the integral here + +is the same as +the integral here. + +And this is the so-called +Maxwell construction. + +So what that means is that +originally I was telling you + +over here that there is some +portion of the curve that + +violates all kinds +of thermodynamics. + +And you should not access it. + +And this other argument that +we are pursuing here says that + +actually the regions that you +cannot access are beyond that. + +There's a portion that +extends in this direction, + +and a portion that +extends in that direction. + +And really there's a portion +that you can access up to here, + +and a portion that you +can access up to here. + +And maybe you +should sort of then + +join them by a straight +line and make an analog + +with what we have over there. + +Now, in another thing, +another way of looking at this + +is that the green portion +is certainly unstable, + +violates all kinds of +thermodynamic conditions. + +And people argue that +these other portions that + +have the right slope are +in some sense metastable. + +So this would be a +stable equilibrium. + +This would be an +unstable equilibrium. + +And a metastable equilibrium +is that you are at a minimum, + +but there's a deeper +minimum somewhere else. + +And the picture is that if +you manage to take your gas + +and put additional +pressure on it, + +there is a region where there +is a coexistence with the liquid + +which is better in terms +of free energy, et cetera. + +But there could be some +kind of a kinetic barrier, + +like nucleation or whatever, +that prevents you to go there. + +And this again is something +that is experimentally observed. + +If you try to rapidly +pressurize a gas, + +you could sometimes avoid +and not make your transition + +to the liquid state +at the right pressure. + +But if you were to do +things sufficiently slowly, + +you would ultimately +reach this point + +that corresponds to +the true equilibrium + +pressure of making +this transition. + +Now, the thing is that +somehow this whole story + +is not very satisfactory. + +I started with +some rearrangement + +of some perturbative to +arrive at this equation. + +This equation has +this unstable portion. + +And somehow I'm trying to relate +something that makes absolutely + +no thermodynamic +sense and try to gain + +from it some idea about what is +happening in a real liquid gas + +system. + +So it would be +good if all of this + +could be more formally +described within a framework + +where all of the approximations, +et cetera, are clear, + +and we know what's going on. + +And so next time, +we will do that. + +We will essentially developed a +much more systematic formalism + +for calculating the properties +of an interacting gas, + +and see that we get this, and +we also understand why it fails. \ No newline at end of file diff --git a/TiHHz3sKDbY.txt b/TiHHz3sKDbY.txt new file mode 100644 index 0000000000000000000000000000000000000000..7910b393ff6723fd7b79e4807df5dcfcd901bd9e --- /dev/null +++ b/TiHHz3sKDbY.txt @@ -0,0 +1,12099 @@ +align:start position:0% + +good afternoon so um we + + align:start position:0% +good afternoon so um we + + + align:start position:0% +good afternoon so um we +spent our last lecture laying out some + + align:start position:0% +spent our last lecture laying out some + + + align:start position:0% +spent our last lecture laying out some +of the basic foundations making a couple + + align:start position:0% +of the basic foundations making a couple + + + align:start position:0% +of the basic foundations making a couple +of definitions I want to quickly recap + + align:start position:0% +of definitions I want to quickly recap + + + align:start position:0% +of definitions I want to quickly recap +the most important concepts and + + align:start position:0% +the most important concepts and + + + align:start position:0% +the most important concepts and +definitions and then maybe blunt I kind + + align:start position:0% +definitions and then maybe blunt I kind + + + align:start position:0% +definitions and then maybe blunt I kind +of want to get through these definitions + + align:start position:0% +of want to get through these definitions + + + align:start position:0% +of want to get through these definitions +which I think are it's important to do + + align:start position:0% +which I think are it's important to do + + + align:start position:0% +which I think are it's important to do +them precisely but + + align:start position:0% +them precisely but + + + align:start position:0% +them precisely but +there's nothing significantly + + align:start position:0% +there's nothing significantly + + + align:start position:0% +there's nothing significantly +challenging about them we just need to + + align:start position:0% +challenging about them we just need to + + + align:start position:0% +challenging about them we just need to +make sure they are defined very + + align:start position:0% +make sure they are defined very + + + align:start position:0% +make sure they are defined very +precisely so now that you've kind of + + align:start position:0% +precisely so now that you've kind of + + + align:start position:0% +precisely so now that you've kind of +seen the style of these things I would + + align:start position:0% +seen the style of these things I would + + + align:start position:0% +seen the style of these things I would +like to sort of move through the next + + align:start position:0% +like to sort of move through the next + + + align:start position:0% +like to sort of move through the next +batch of these definitions quickly + + align:start position:0% +batch of these definitions quickly + + + align:start position:0% +batch of these definitions quickly +enough that we can start to move into + + align:start position:0% +enough that we can start to move into + + + align:start position:0% +enough that we can start to move into +more interesting material so a quick + + align:start position:0% +more interesting material so a quick + + + align:start position:0% +more interesting material so a quick +recap and my apologies my daughter has + + align:start position:0% +recap and my apologies my daughter has + + + align:start position:0% +recap and my apologies my daughter has +some kind of a virus that I am + + align:start position:0% +some kind of a virus that I am + + + align:start position:0% +some kind of a virus that I am +desperately trying to make sure + + align:start position:0% +desperately trying to make sure + + + align:start position:0% +desperately trying to make sure +I do not catch and so I will be + + align:start position:0% +I do not catch and so I will be + + + align:start position:0% +I do not catch and so I will be +hydrating during this lecture so I just + + align:start position:0% +hydrating during this lecture so I just + + + align:start position:0% +hydrating during this lecture so I just +want to recap some of the most important + + align:start position:0% +want to recap some of the most important + + + align:start position:0% +want to recap some of the most important +cop since we went over so this whole + + align:start position:0% +cop since we went over so this whole + + + align:start position:0% +cop since we went over so this whole +class is essentially a study in + + align:start position:0% +class is essentially a study in + + + align:start position:0% +class is essentially a study in +space-time okay we're gonna later we're + + align:start position:0% +space-time okay we're gonna later we're + + + align:start position:0% +space-time okay we're gonna later we're +going to connect space-time to gravity + + align:start position:0% +going to connect space-time to gravity + + + align:start position:0% +going to connect space-time to gravity +and general relativity is going to + + align:start position:0% +and general relativity is going to + + + align:start position:0% +and general relativity is going to +become the relativistic theory of + + align:start position:0% +become the relativistic theory of + + + align:start position:0% +become the relativistic theory of +gravity so we began with a fairly + + align:start position:0% +gravity so we began with a fairly + + + align:start position:0% +gravity so we began with a fairly +mathematical definition space-time is a + + align:start position:0% +mathematical definition space-time is a + + + align:start position:0% +mathematical definition space-time is a +manifold of events that is endowed with + + align:start position:0% +manifold of events that is endowed with + + + align:start position:0% +manifold of events that is endowed with +a metric manifold for our purposes is + + align:start position:0% +a metric manifold for our purposes is + + + align:start position:0% +a metric manifold for our purposes is +essentially just a set in which we + + align:start position:0% +essentially just a set in which we + + + align:start position:0% +essentially just a set in which we +understand how different members of the + + align:start position:0% +understand how different members of the + + + align:start position:0% +understand how different members of the +set are connected to each other events + + align:start position:0% +set are connected to each other events + + + align:start position:0% +set are connected to each other events +are really just when and where something + + align:start position:0% +are really just when and where something + + + align:start position:0% +are really just when and where something +happens we haven't precisely defined + + align:start position:0% +happens we haven't precisely defined + + + align:start position:0% +happens we haven't precisely defined +metric yet we will soon okay but + + align:start position:0% +metric yet we will soon okay but + + + align:start position:0% +metric yet we will soon okay but +intuitively disregard it as some kind of + + align:start position:0% +intuitively disregard it as some kind of + + + align:start position:0% +intuitively disregard it as some kind of +a mathematical object that gives me a + + align:start position:0% +a mathematical object that gives me a + + + align:start position:0% +a mathematical object that gives me a +notion of distance between these events + + align:start position:0% +notion of distance between these events + + + align:start position:0% +notion of distance between these events +I was tried and I will continue to try + + align:start position:0% +I was tried and I will continue to try + + + align:start position:0% +I was tried and I will continue to try +to be very careful to make a distinction + + align:start position:0% +to be very careful to make a distinction + + + align:start position:0% +to be very careful to make a distinction +between geometric objects that live in + + align:start position:0% +between geometric objects that live in + + + align:start position:0% +between geometric objects that live in +the manifold the events themselves with + + align:start position:0% +the manifold the events themselves with + + + align:start position:0% +the manifold the events themselves with +things like a displacement vector + + align:start position:0% +things like a displacement vector + + + align:start position:0% +things like a displacement vector +between two events other vectors which I + + align:start position:0% +between two events other vectors which I + + + align:start position:0% +between two events other vectors which I +will recap the definition of in just a + + align:start position:0% +will recap the definition of in just a + + + align:start position:0% +will recap the definition of in just a +moment they have an existence and sort + + align:start position:0% +moment they have an existence and sort + + + align:start position:0% +moment they have an existence and sort +of a reality to them that is deeper and + + align:start position:0% +of a reality to them that is deeper and + + + align:start position:0% +of a reality to them that is deeper and +more fundamental than the representation + + align:start position:0% +more fundamental than the representation + + + align:start position:0% +more fundamental than the representation +of that object okay so when I state the + + align:start position:0% +of that object okay so when I state the + + + align:start position:0% +of that object okay so when I state the +displacement vector is Delta X Delta Y + + align:start position:0% +displacement vector is Delta X Delta Y + + + align:start position:0% +displacement vector is Delta X Delta Y +delta T Delta X Delta Y Delta Z that is + + align:start position:0% +delta T Delta X Delta Y Delta Z that is + + + align:start position:0% +delta T Delta X Delta Y Delta Z that is +according to observer oh and when I + + align:start position:0% +according to observer oh and when I + + + align:start position:0% +according to observer oh and when I +write that down I will be very clear for + + align:start position:0% +write that down I will be very clear for + + + align:start position:0% +write that down I will be very clear for +as much as possible I will occasionally + + align:start position:0% +as much as possible I will occasionally + + + align:start position:0% +as much as possible I will occasionally +screw this up but I will try to write + + align:start position:0% +screw this up but I will try to write + + + align:start position:0% +screw this up but I will try to write +this down without using an equal sign + + align:start position:0% +this down without using an equal sign + + + align:start position:0% +this down without using an equal sign +okay equal sign implies a degree of + + align:start position:0% +okay equal sign implies a degree of + + + align:start position:0% +okay equal sign implies a degree of +reality that I do not want to impart to + + align:start position:0% +reality that I do not want to impart to + + + align:start position:0% +reality that I do not want to impart to +that representation so an equal dot with + + align:start position:0% +that representation so an equal dot with + + + align:start position:0% +that representation so an equal dot with +a little oh here that's my personal + + align:start position:0% +a little oh here that's my personal + + + align:start position:0% +a little oh here that's my personal +notation for Delta X is represented by + + align:start position:0% +notation for Delta X is represented by + + + align:start position:0% +notation for Delta X is represented by +these components according to observer + + align:start position:0% +these components according to observer + + + align:start position:0% +these components according to observer +oh and for shorthand I will sometimes + + align:start position:0% +oh and for shorthand I will sometimes + + + align:start position:0% +oh and for shorthand I will sometimes +just write this by the collection of + + align:start position:0% +just write this by the collection of + + + align:start position:0% +just write this by the collection of +indices Delta X alpha a different + + align:start position:0% +indices Delta X alpha a different + + + align:start position:0% +indices Delta X alpha a different +observer Oh bar will represent their + + align:start position:0% +observer Oh bar will represent their + + + align:start position:0% +observer Oh bar will represent their +that they will represent this this + + align:start position:0% +that they will represent this this + + + align:start position:0% +that they will represent this this +vector using it's the exact same + + align:start position:0% +vector using it's the exact same + + + align:start position:0% +vector using it's the exact same +geometric object they all agree that + + align:start position:0% +geometric object they all agree that + + + align:start position:0% +geometric object they all agree that +it's this displacement between two + + align:start position:0% +it's this displacement between two + + + align:start position:0% +it's this displacement between two +physical events in space-time but they + + align:start position:0% +physical events in space-time but they + + + align:start position:0% +physical events in space-time but they +assign different coordinates to it they + + align:start position:0% +assign different coordinates to it they + + + align:start position:0% +assign different coordinates to it they +give a different representation to it + + align:start position:0% +give a different representation to it + + + align:start position:0% +give a different representation to it +and we find that representation using a + + align:start position:0% +and we find that representation using a + + + align:start position:0% +and we find that representation using a +Lorentz transformation okay and I'm not + + align:start position:0% +Lorentz transformation okay and I'm not + + + align:start position:0% +Lorentz transformation okay and I'm not +gonna write explicitly the Lorentz + + align:start position:0% +gonna write explicitly the Lorentz + + + align:start position:0% +gonna write explicitly the Lorentz +transformation matrix lambda I gave it + + align:start position:0% +transformation matrix lambda I gave it + + + align:start position:0% +transformation matrix lambda I gave it +in the last lecture and I'm assuming + + align:start position:0% +in the last lecture and I'm assuming + + + align:start position:0% +in the last lecture and I'm assuming +you're all experts in special relativity + + align:start position:0% +you're all experts in special relativity + + + align:start position:0% +you're all experts in special relativity +and I don't need to go over that so I + + align:start position:0% +and I don't need to go over that so I + + + align:start position:0% +and I don't need to go over that so I +will then using this sort of the + + align:start position:0% +will then using this sort of the + + + align:start position:0% +will then using this sort of the +prototype the general notion of a vector + + align:start position:0% +prototype the general notion of a vector + + + align:start position:0% +prototype the general notion of a vector +in space-time which we will often call a + + align:start position:0% +in space-time which we will often call a + + + align:start position:0% +in space-time which we will often call a +for vector for the obvious reason that + + align:start position:0% +for vector for the obvious reason that + + + align:start position:0% +for vector for the obvious reason that +it has four components I'm gonna treat + + align:start position:0% +it has four components I'm gonna treat + + + align:start position:0% +it has four components I'm gonna treat +that as any quartet of numbers that has + + align:start position:0% +that as any quartet of numbers that has + + + align:start position:0% +that as any quartet of numbers that has +transformation properties just like the + + align:start position:0% +transformation properties just like the + + + align:start position:0% +transformation properties just like the +displacement factor I just went over so + + align:start position:0% +displacement factor I just went over so + + + align:start position:0% +displacement factor I just went over so +if there's some quantity a that has time + + align:start position:0% +if there's some quantity a that has time + + + align:start position:0% +if there's some quantity a that has time +like an X or Y and a Z component as long + + align:start position:0% +like an X or Y and a Z component as long + + + align:start position:0% +like an X or Y and a Z component as long +as a different observer for reasons + + align:start position:0% +as a different observer for reasons + + + align:start position:0% +as a different observer for reasons +having to do with the underlying physics + + align:start position:0% +having to do with the underlying physics + + + align:start position:0% +having to do with the underlying physics +of whatever the heck this a is as long + + align:start position:0% +of whatever the heck this a is as long + + + align:start position:0% +of whatever the heck this a is as long +as that different observer relates their + + align:start position:0% +as that different observer relates their + + + align:start position:0% +as that different observer relates their +components to observer OHS components + + align:start position:0% +components to observer OHS components + + + align:start position:0% +components to observer OHS components +via Lorentz transformation you got + + align:start position:0% +via Lorentz transformation you got + + + align:start position:0% +via Lorentz transformation you got +yourself a four vector okay any random + + align:start position:0% +yourself a four vector okay any random + + + align:start position:0% +yourself a four vector okay any random +set of four numbers that ain't a four + + align:start position:0% +set of four numbers that ain't a four + + + align:start position:0% +set of four numbers that ain't a four +vector ah you need to have some physics + + align:start position:0% +vector ah you need to have some physics + + + align:start position:0% +vector ah you need to have some physics +associated with it and the physics has + + align:start position:0% +associated with it and the physics has + + + align:start position:0% +associated with it and the physics has +to tell it that it's a thing that's + + align:start position:0% +to tell it that it's a thing that's + + + align:start position:0% +to tell it that it's a thing that's +related by Lorentz transformation + + align:start position:0% +related by Lorentz transformation + + + align:start position:0% +related by Lorentz transformation +alright + + align:start position:0% +alright + + + align:start position:0% +alright +so + + align:start position:0% + + + + align:start position:0% + +I want to pick up this discussion by + + align:start position:0% +I want to pick up this discussion by + + + align:start position:0% +I want to pick up this discussion by +introducing four particularly important + + align:start position:0% +introducing four particularly important + + + align:start position:0% +introducing four particularly important +and special vectors which to be honest + + align:start position:0% +and special vectors which to be honest + + + align:start position:0% +and special vectors which to be honest +we're not going to use too much beyond + + align:start position:0% +we're not going to use too much beyond + + + align:start position:0% +we're not going to use too much beyond +some of this the first couple weeks or + + align:start position:0% +some of this the first couple weeks or + + + align:start position:0% +some of this the first couple weeks or +so of the course but they're very useful + + align:start position:0% +so of the course but they're very useful + + + align:start position:0% +so of the course but they're very useful +and one should often bear in mind even + + align:start position:0% +and one should often bear in mind even + + + align:start position:0% +and one should often bear in mind even +later in the course and they've sort of + + align:start position:0% +later in the course and they've sort of + + + align:start position:0% +later in the course and they've sort of +disappeared that they're kind of they're + + align:start position:0% +disappeared that they're kind of they're + + + align:start position:0% +disappeared that they're kind of they're +coming along for the ride secret like + + align:start position:0% +coming along for the ride secret like + + + align:start position:0% +coming along for the ride secret like +these are basis vectors okay + + align:start position:0% + + + + align:start position:0% + +so if I go into frame Oh just gonna pick + + align:start position:0% +so if I go into frame Oh just gonna pick + + + align:start position:0% +so if I go into frame Oh just gonna pick +some particular reference frame I can + + align:start position:0% + + + + align:start position:0% + +immediately write down for special + + align:start position:0% +immediately write down for special + + + align:start position:0% +immediately write down for special +vectors so + + align:start position:0% +vectors so + + + align:start position:0% +vectors so +remember this is a Cartesian type of + + align:start position:0% +remember this is a Cartesian type of + + + align:start position:0% +remember this is a Cartesian type of +coordinate system so I'm going to + + align:start position:0% +coordinate system so I'm going to + + + align:start position:0% +coordinate system so I'm going to +introduce easy + + align:start position:0% +introduce easy + + + align:start position:0% +introduce easy +Rho I'm + + align:start position:0% +Rho I'm + + + align:start position:0% +Rho I'm +gonna represent this by just the number + + align:start position:0% +gonna represent this by just the number + + + align:start position:0% +gonna represent this by just the number +one and the time like slot and zero + + align:start position:0% +one and the time like slot and zero + + + align:start position:0% +one and the time like slot and zero +everywhere else e 1 + + align:start position:0% +everywhere else e 1 + + + align:start position:0% +everywhere else e 1 +or e X if you prefer I'm + + align:start position:0% + + + + align:start position:0% + +gonna write that down like so and + + align:start position:0% +gonna write that down like so and + + + align:start position:0% +gonna write that down like so and +you can kind of see where I'm going with + + align:start position:0% +you can kind of see where I'm going with + + + align:start position:0% +you can kind of see where I'm going with +this + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +the + + align:start position:0% +the + + + align:start position:0% +the +analogy if you've all seen unit vectors + + align:start position:0% +analogy if you've all seen unit vectors + + + align:start position:0% +analogy if you've all seen unit vectors +in other classes hopefully this is + + align:start position:0% +in other classes hopefully this is + + + align:start position:0% +in other classes hopefully this is +fairly obvious what I'm doing okay I'm + + align:start position:0% +fairly obvious what I'm doing okay I'm + + + align:start position:0% +fairly obvious what I'm doing okay I'm +just picking out a set of you know + + align:start position:0% +just picking out a set of you know + + + align:start position:0% +just picking out a set of you know +little dimensionless simple quantities + + align:start position:0% +little dimensionless simple quantities + + + align:start position:0% +little dimensionless simple quantities +that point along the preferred + + align:start position:0% +that point along the preferred + + + align:start position:0% +that point along the preferred +directions that I've set up in this + + align:start position:0% +directions that I've set up in this + + + align:start position:0% +directions that I've set up in this +inertial reference frame a compact way + + align:start position:0% +inertial reference frame a compact way + + + align:start position:0% +inertial reference frame a compact way +of writing this so + + align:start position:0% + + + + align:start position:0% + +notice I have four of these vectors and + + align:start position:0% +notice I have four of these vectors and + + + align:start position:0% +notice I have four of these vectors and +these vectors each have four components + + align:start position:0% +these vectors each have four components + + + align:start position:0% +these vectors each have four components +and so what I can say is that the + + align:start position:0% + + + + align:start position:0% + +beta component of unit vector E alpha is + + align:start position:0% + + + + align:start position:0% + +represented according to observer oh by + + align:start position:0% +represented according to observer oh by + + + align:start position:0% +represented according to observer oh by +Delta alpha beta the Kronecker Delta + + align:start position:0% +Delta alpha beta the Kronecker Delta + + + align:start position:0% +Delta alpha beta the Kronecker Delta +okay if + + align:start position:0% +okay if + + + align:start position:0% +okay if +you're not familiar with this one I'm + + align:start position:0% +you're not familiar with this one I'm + + + align:start position:0% +you're not familiar with this one I'm +usually reluctant to send you to + + align:start position:0% +usually reluctant to send you to + + + align:start position:0% +usually reluctant to send you to +Wikipedia but in this case wiki + + align:start position:0% +Wikipedia but in this case wiki + + + align:start position:0% +Wikipedia but in this case wiki +the Kronecker Delta yeah + + align:start position:0% +the Kronecker Delta yeah + + + align:start position:0% +the Kronecker Delta yeah +so that that kind of what that does just + + align:start position:0% +so that that kind of what that does just + + + align:start position:0% +so that that kind of what that does just +emphasize is that at least in by the way + + align:start position:0% +emphasize is that at least in by the way + + + align:start position:0% +emphasize is that at least in by the way +I should put little O's underneath all + + align:start position:0% +I should put little O's underneath all + + + align:start position:0% +I should put little O's underneath all +of these things because I have chosen + + align:start position:0% +of these things because I have chosen + + + align:start position:0% +of these things because I have chosen +this according to observer OHS + + align:start position:0% +this according to observer OHS + + + align:start position:0% +this according to observer OHS +representation so this is just saying + + align:start position:0% +representation so this is just saying + + + align:start position:0% +representation so this is just saying +that according to observer oh these are + + align:start position:0% +that according to observer oh these are + + + align:start position:0% +that according to observer oh these are +four very special vectors the utility of + + align:start position:0% +four very special vectors the utility of + + + align:start position:0% +four very special vectors the utility of +these things back + + align:start position:0% + + + + align:start position:0% + +to be honest thing okay + + align:start position:0% + + + + align:start position:0% + +the utility of doing this is + + align:start position:0% + + + + align:start position:0% + +that if I now want to write the vector a + + align:start position:0% +that if I now want to write the vector a + + + align:start position:0% +that if I now want to write the vector a +as a geometric object I can combine the + + align:start position:0% +as a geometric object I can combine the + + + align:start position:0% +as a geometric object I can combine the +components that observer o uses with the + + align:start position:0% +components that observer o uses with the + + + align:start position:0% +components that observer o uses with the +basis vectors that observer o uses and I + + align:start position:0% +basis vectors that observer o uses and I + + + align:start position:0% +basis vectors that observer o uses and I +can sum them all together I can put them + + align:start position:0% +can sum them all together I can put them + + + align:start position:0% +can sum them all together I can put them +together and then I've got the it's not + + align:start position:0% +together and then I've got the it's not + + + align:start position:0% +together and then I've got the it's not +a representation that's the damn vector + + align:start position:0% +a representation that's the damn vector + + + align:start position:0% +a representation that's the damn vector +okay I put it all together using sort of + + align:start position:0% +okay I put it all together using sort of + + + align:start position:0% +okay I put it all together using sort of +an internally consistent set of numbers + + align:start position:0% +an internally consistent set of numbers + + + align:start position:0% +an internally consistent set of numbers +and basis vectors and so + + align:start position:0% +and basis vectors and so + + + align:start position:0% +and basis vectors and so +I am free to say this + + align:start position:0% +I am free to say this + + + align:start position:0% +I am free to say this +where + + align:start position:0% + + + + align:start position:0% + +I actually use an actual equal sign okay + + align:start position:0% + + + + align:start position:0% + +you might stop and think well but those + + align:start position:0% +you might stop and think well but those + + + align:start position:0% +you might stop and think well but those +aren't the components that observer Oh + + align:start position:0% +aren't the components that observer Oh + + + align:start position:0% +aren't the components that observer Oh +bar is it would use and you're right + + align:start position:0% +bar is it would use and you're right + + + align:start position:0% +bar is it would use and you're right +observer Oh bar would not use those + + align:start position:0% +observer Oh bar would not use those + + + align:start position:0% +observer Oh bar would not use those +components they would also not use those + + align:start position:0% +components they would also not use those + + + align:start position:0% +components they would also not use those +basis vectors we're gonna talk about how + + align:start position:0% +basis vectors we're gonna talk about how + + + align:start position:0% +basis vectors we're gonna talk about how +those things change but observer Oh bar + + align:start position:0% +those things change but observer Oh bar + + + align:start position:0% +those things change but observer Oh bar +does agree that if they were handed owes + + align:start position:0% +does agree that if they were handed owes + + + align:start position:0% +does agree that if they were handed owes +components in those basis vectors this + + align:start position:0% +components in those basis vectors this + + + align:start position:0% +components in those basis vectors this +would give me a complete representation + + align:start position:0% +would give me a complete representation + + + align:start position:0% +would give me a complete representation +of what the vector is okay so + + align:start position:0% +of what the vector is okay so + + + align:start position:0% +of what the vector is okay so +again I'm really harping on this sort of + + align:start position:0% +again I'm really harping on this sort of + + + align:start position:0% +again I'm really harping on this sort of +distinction between the geometric object + + align:start position:0% +distinction between the geometric object + + + align:start position:0% +distinction between the geometric object +and the representation this is the + + align:start position:0% +and the representation this is the + + + align:start position:0% +and the representation this is the +geometric object we can take advantage + + align:start position:0% +geometric object we can take advantage + + + align:start position:0% +geometric object we can take advantage +of this okay + + align:start position:0% +of this okay + + + align:start position:0% +of this okay +the fact that that combination of things + + align:start position:0% +the fact that that combination of things + + + align:start position:0% +the fact that that combination of things +is the geometric object is a tool that + + align:start position:0% +is the geometric object is a tool that + + + align:start position:0% +is the geometric object is a tool that +I'm gonna now it's a fact that I'm going + + align:start position:0% +I'm gonna now it's a fact that I'm going + + + align:start position:0% +I'm gonna now it's a fact that I'm going +to exploit in order to figure out how my + + align:start position:0% +to exploit in order to figure out how my + + + align:start position:0% +to exploit in order to figure out how my +basis vectors transform when I change + + align:start position:0% +basis vectors transform when I change + + + align:start position:0% +basis vectors transform when I change +reference frames so + + align:start position:0% + + + + align:start position:0% + +we just repeat what I wrote up there ah + + align:start position:0% +we just repeat what I wrote up there ah + + + align:start position:0% +we just repeat what I wrote up there ah +but + + align:start position:0% +but + + + align:start position:0% +but +whoops + + align:start position:0% +whoops + + + align:start position:0% +whoops +good + + align:start position:0% + + + + align:start position:0% + +point for just a slight editorial + + align:start position:0% +point for just a slight editorial + + + align:start position:0% +point for just a slight editorial +comment um when you're talking and + + align:start position:0% +comment um when you're talking and + + + align:start position:0% +comment um when you're talking and +writing and there are millions of little + + align:start position:0% +writing and there are millions of little + + + align:start position:0% +writing and there are millions of little +subscripts and indices sometimes the + + align:start position:0% +subscripts and indices sometimes the + + + align:start position:0% +subscripts and indices sometimes the +brain and the appendages get out of sync + + align:start position:0% +brain and the appendages get out of sync + + + align:start position:0% +brain and the appendages get out of sync +with one another I caught that one I + + align:start position:0% +with one another I caught that one I + + + align:start position:0% +with one another I caught that one I +don't always okay so if you see + + align:start position:0% +don't always okay so if you see + + + align:start position:0% +don't always okay so if you see +something like that and you kind of go + + align:start position:0% +something like that and you kind of go + + + align:start position:0% +something like that and you kind of go +umm why did that alpha magically turn + + align:start position:0% +umm why did that alpha magically turn + + + align:start position:0% +umm why did that alpha magically turn +into a beta it's probably a mistake + + align:start position:0% +into a beta it's probably a mistake + + + align:start position:0% +into a beta it's probably a mistake +please call it out okay all right so + + align:start position:0% +please call it out okay all right so + + + align:start position:0% +please call it out okay all right so +this is how I build this geometric + + align:start position:0% +this is how I build this geometric + + + align:start position:0% +this is how I build this geometric +object using the components and the + + align:start position:0% +object using the components and the + + + align:start position:0% +object using the components and the +basis vectors as measured by O as used + + align:start position:0% +basis vectors as measured by O as used + + + align:start position:0% +basis vectors as measured by O as used +by observer oh let's now write out what + + align:start position:0% +by observer oh let's now write out what + + + align:start position:0% +by observer oh let's now write out what +they would be if they were measured by a + + align:start position:0% +they would be if they were measured by a + + + align:start position:0% +they would be if they were measured by a +different + + align:start position:0% +different + + + align:start position:0% +different +observer and o'Barr okay + + align:start position:0% +observer and o'Barr okay + + + align:start position:0% +observer and o'Barr okay +I know how to get components the barred + + align:start position:0% +I know how to get components the barred + + + align:start position:0% +I know how to get components the barred +components from the unbarred components + + align:start position:0% +components from the unbarred components + + + align:start position:0% +components from the unbarred components +I don't yet know how to get the unbarred + + align:start position:0% +I don't yet know how to get the unbarred + + + align:start position:0% +I don't yet know how to get the unbarred +Basin to be the bard basis vectors and + + align:start position:0% +Basin to be the bard basis vectors and + + + align:start position:0% +Basin to be the bard basis vectors and +the unbarred basis vectors but I know + + align:start position:0% +the unbarred basis vectors but I know + + + align:start position:0% +the unbarred basis vectors but I know +that whatever they exist and that once I + + align:start position:0% +that whatever they exist and that once I + + + align:start position:0% +that whatever they exist and that once I +know what they are this equation is true + + align:start position:0% +know what they are this equation is true + + + align:start position:0% +know what they are this equation is true +okay these are just two different ways + + align:start position:0% +okay these are just two different ways + + + align:start position:0% +okay these are just two different ways +of writing this geometric object which + + align:start position:0% +of writing this geometric object which + + + align:start position:0% +of writing this geometric object which +every observer agrees has this existence + + align:start position:0% +every observer agrees has this existence + + + align:start position:0% +every observer agrees has this existence +that transcends the representation so + + align:start position:0% +that transcends the representation so + + + align:start position:0% +that transcends the representation so +let's rewrite what I've got on the + + align:start position:0% +let's rewrite what I've got on the + + + align:start position:0% +let's rewrite what I've got on the +right-hand side of the the rightmost + + align:start position:0% +right-hand side of the the rightmost + + + align:start position:0% +right-hand side of the the rightmost +equal sign here I'm gonna write this as + + align:start position:0% +equal sign here I'm gonna write this as + + + align:start position:0% +equal sign here I'm gonna write this as +lambda + + align:start position:0% +lambda + + + align:start position:0% +lambda +mu + + align:start position:0% +mu + + + align:start position:0% +mu +bar beta + + align:start position:0% +bar beta + + + align:start position:0% +bar beta +a beta and + + align:start position:0% + + + + align:start position:0% + +then now I'm going to use a trick which + + align:start position:0% +then now I'm going to use a trick which + + + align:start position:0% +then now I'm going to use a trick which +is what the tonight units much a trick + + align:start position:0% +is what the tonight units much a trick + + + align:start position:0% +is what the tonight units much a trick +but just gonna use a fact that is great + + align:start position:0% +but just gonna use a fact that is great + + + align:start position:0% +but just gonna use a fact that is great +when you're working in index notation + + align:start position:0% +when you're working in index notation + + + align:start position:0% +when you're working in index notation +okay so often when students first + + align:start position:0% +okay so often when students first + + + align:start position:0% +okay so often when students first +encounter this kind of notation your + + align:start position:0% +encounter this kind of notation your + + + align:start position:0% +encounter this kind of notation your +instinct is to try to write everything + + align:start position:0% +instinct is to try to write everything + + + align:start position:0% +instinct is to try to write everything +out using matrices and things like row + + align:start position:0% +out using matrices and things like row + + + align:start position:0% +out using matrices and things like row +vectors and column vectors okay it's a + + align:start position:0% +vectors and column vectors okay it's a + + + align:start position:0% +vectors and column vectors okay it's a +natural thing to do I urge you to get + + align:start position:0% +natural thing to do I urge you to get + + + align:start position:0% +natural thing to do I urge you to get +over that + + align:start position:0% +over that + + + align:start position:0% +over that +if I get some bandwidth for that I'm + + align:start position:0% +if I get some bandwidth for that I'm + + + align:start position:0% +if I get some bandwidth for that I'm +gonna write up a set of notes this + + align:start position:0% +gonna write up a set of notes this + + + align:start position:0% +gonna write up a set of notes this +weekend showing how one can translate at + + align:start position:0% +weekend showing how one can translate at + + + align:start position:0% +weekend showing how one can translate at +least two by two objects and one that to + + align:start position:0% +least two by two objects and one that to + + + align:start position:0% +least two by two objects and one that to +index objects and one ending objects in + + align:start position:0% +index objects and one ending objects in + + + align:start position:0% +index objects and one ending objects in +a consistent way between matrices + + align:start position:0% +a consistent way between matrices + + + align:start position:0% +a consistent way between matrices +and row vectors and column vectors but + + align:start position:0% +and row vectors and column vectors but + + + align:start position:0% +and row vectors and column vectors but +we're rapidly going to start getting + + align:start position:0% +we're rapidly going to start getting + + + align:start position:0% +we're rapidly going to start getting +into objects that are bigger than that + + align:start position:0% +into objects that are bigger than that + + + align:start position:0% +into objects that are bigger than that +for which trying to represent them in + + align:start position:0% +for which trying to represent them in + + + align:start position:0% +for which trying to represent them in +matrix like form gets untenable okay and + + align:start position:0% +matrix like form gets untenable okay and + + + align:start position:0% +matrix like form gets untenable okay and +a little while we're gonna have a three + + align:start position:0% +a little while we're gonna have a three + + + align:start position:0% +a little while we're gonna have a three +indexed object since we don't have + + align:start position:0% +indexed object since we don't have + + + align:start position:0% +indexed object since we don't have +three-dimensional chalkboards making + + align:start position:0% +three-dimensional chalkboards making + + + align:start position:0% +three-dimensional chalkboards making +this sort of matrix representation that + + align:start position:0% +this sort of matrix representation that + + + align:start position:0% +this sort of matrix representation that +is challenging soon after that we'll + + align:start position:0% +is challenging soon after that we'll + + + align:start position:0% +is challenging soon after that we'll +have four index objects and we'll + + align:start position:0% +have four index objects and we'll + + + align:start position:0% +have four index objects and we'll +occasionally need to take derivatives of + + align:start position:0% +occasionally need to take derivatives of + + + align:start position:0% +occasionally need to take derivatives of +that for an index object giving us a 5 + + align:start position:0% +that for an index object giving us a 5 + + + align:start position:0% +that for an index object giving us a 5 +index object at that point the ability + + align:start position:0% +index object at that point the ability + + + align:start position:0% +index object at that point the ability +to sort of treat them like matrices is + + align:start position:0% +to sort of treat them like matrices is + + + align:start position:0% +to sort of treat them like matrices is +hopeless so really you should just be + + align:start position:0% +hopeless so really you should just be + + + align:start position:0% +hopeless so really you should just be +thinking of this as ordinary + + align:start position:0% +thinking of this as ordinary + + + align:start position:0% +thinking of this as ordinary +multiplication of the numbers that are + + align:start position:0% +multiplication of the numbers that are + + + align:start position:0% +multiplication of the numbers that are +represented by these components as + + align:start position:0% +represented by these components as + + + align:start position:0% +represented by these components as +written out here and an ordinary + + align:start position:0% +written out here and an ordinary + + + align:start position:0% +written out here and an ordinary +multiplication like this I can swap the + + align:start position:0% +multiplication like this I can swap the + + + align:start position:0% +multiplication like this I can swap the +order of I + + align:start position:0% +order of I + + + align:start position:0% +order of I +can just go ahead and swap the order of + + align:start position:0% +can just go ahead and swap the order of + + + align:start position:0% +can just go ahead and swap the order of +multiplication + + align:start position:0% +multiplication + + + align:start position:0% +multiplication +very easily here so I'm gonna do is move + + align:start position:0% + + + + align:start position:0% + +the what + + align:start position:0% + + + + align:start position:0% + +I'm doing sorry about that I misread my + + align:start position:0% +I'm doing sorry about that I misread my + + + align:start position:0% +I'm doing sorry about that I misread my +notes I'm + + align:start position:0% + + + + align:start position:0% + +just gonna move the a on to the other + + align:start position:0% +just gonna move the a on to the other + + + align:start position:0% +just gonna move the a on to the other +side of my lambda oops + + align:start position:0% +side of my lambda oops + + + align:start position:0% +side of my lambda oops +okay + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +then I'm going to use the fact that beta + + align:start position:0% +then I'm going to use the fact that beta + + + align:start position:0% +then I'm going to use the fact that beta +on my right-hand side is a dummy index + + align:start position:0% +on my right-hand side is a dummy index + + + align:start position:0% +on my right-hand side is a dummy index +so + + align:start position:0% + + + + align:start position:0% + +in that final expression I wrote down + + align:start position:0% +in that final expression I wrote down + + + align:start position:0% +in that final expression I wrote down +over there beta is a dummy index and I'm + + align:start position:0% +over there beta is a dummy index and I'm + + + align:start position:0% +over there beta is a dummy index and I'm +free to adjust it to put it into a form + + align:start position:0% +free to adjust it to put it into a form + + + align:start position:0% +free to adjust it to put it into a form +that's more convenient for me so + + align:start position:0% + + + + align:start position:0% + +let's begin let me just write where I've + + align:start position:0% +let's begin let me just write where I've + + + align:start position:0% +let's begin let me just write where I've +got this equation right now over there + + align:start position:0% +got this equation right now over there + + + align:start position:0% +got this equation right now over there +so P alpha a alpha e alpha equals what + + align:start position:0% +so P alpha a alpha e alpha equals what + + + align:start position:0% +so P alpha a alpha e alpha equals what +I've got then is component a beta + + align:start position:0% +I've got then is component a beta + + + align:start position:0% +I've got then is component a beta +lambda bar beta mu + + align:start position:0% + + + + align:start position:0% + +bar that so I'm gonna remap my dummy + + align:start position:0% +bar that so I'm gonna remap my dummy + + + align:start position:0% +bar that so I'm gonna remap my dummy +index + + align:start position:0% + + + + align:start position:0% + +the + + align:start position:0% +the + + + align:start position:0% +the +reason I did that is I can now move this + + align:start position:0% +reason I did that is I can now move this + + + align:start position:0% +reason I did that is I can now move this +to the other side and factor out the a + + align:start position:0% +to the other side and factor out the a + + + align:start position:0% +to the other side and factor out the a +alpha okay + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +see that I hope so see what I did was I + + align:start position:0% +see that I hope so see what I did was I + + + align:start position:0% +see that I hope so see what I did was I +arranged this so that I've isolated + + align:start position:0% +arranged this so that I've isolated + + + align:start position:0% +arranged this so that I've isolated +essentially only the transformation of + + align:start position:0% +essentially only the transformation of + + + align:start position:0% +essentially only the transformation of +the basis factor + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +this equation has to hold no matter what + + align:start position:0% +this equation has to hold no matter what + + + align:start position:0% +this equation has to hold no matter what +vector I am working with right it's got + + align:start position:0% +vector I am working with right it's got + + + align:start position:0% +vector I am working with right it's got +a hold for an arbitrary a alpha so the + + align:start position:0% +a hold for an arbitrary a alpha so the + + + align:start position:0% +a hold for an arbitrary a alpha so the +only way that can happen + + align:start position:0% +only way that can happen + + + align:start position:0% +only way that can happen +this + + align:start position:0% + + + + align:start position:0% + +means that my + + align:start position:0% + + + + align:start position:0% + +transformation of basis vectors Oh basil + + align:start position:0% +transformation of basis vectors Oh basil + + + align:start position:0% +transformation of basis vectors Oh basil +wah that looks like this now + + align:start position:0% +wah that looks like this now + + + align:start position:0% +wah that looks like this now +in first inspection you're going to go + + align:start position:0% +in first inspection you're going to go + + + align:start position:0% +in first inspection you're going to go +ah that's exactly what we got for the + + align:start position:0% +ah that's exactly what we got for the + + + align:start position:0% +ah that's exactly what we got for the +components of the four vector caution + + align:start position:0% +components of the four vector caution + + + align:start position:0% +components of the four vector caution +and remind you it's actually on the + + align:start position:0% +and remind you it's actually on the + + + align:start position:0% +and remind you it's actually on the +board over there + + align:start position:0% + + + + align:start position:0% + +okay the + + align:start position:0% +okay the + + + align:start position:0% +okay the +bard component is playing a different + + align:start position:0% +bard component is playing a different + + + align:start position:0% +bard component is playing a different +role than the bard basis vector here + + align:start position:0% +role than the bard basis vector here + + + align:start position:0% +role than the bard basis vector here +okay if you want to get the bard basis + + align:start position:0% +okay if you want to get the bard basis + + + align:start position:0% +okay if you want to get the bard basis +vector from the unbarred basis factor + + align:start position:0% +vector from the unbarred basis factor + + + align:start position:0% +vector from the unbarred basis factor +you need to work with the inverse of + + align:start position:0% +you need to work with the inverse of + + + align:start position:0% +you need to work with the inverse of +this matrix that's what this is telling + + align:start position:0% +this matrix that's what this is telling + + + align:start position:0% +this matrix that's what this is telling +us here okay all + + align:start position:0% +us here okay all + + + align:start position:0% +us here okay all +that being said if you're just working + + align:start position:0% +that being said if you're just working + + + align:start position:0% +that being said if you're just working +through this and you're got you know + + align:start position:0% +through this and you're got you know + + + align:start position:0% +through this and you're got you know +your components set up and you're sort + + align:start position:0% +your components set up and you're sort + + + align:start position:0% +your components set up and you're sort +of hacking through it the algorithm for + + align:start position:0% +of hacking through it the algorithm for + + + align:start position:0% +of hacking through it the algorithm for +you to follow is actually simple really + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +all we're doing is lining up the indices + + align:start position:0% +all we're doing is lining up the indices + + + align:start position:0% +all we're doing is lining up the indices +we're summing over the ones that are + + align:start position:0% +we're summing over the ones that are + + + align:start position:0% +we're summing over the ones that are +repeated and requiring that those that + + align:start position:0% +repeated and requiring that those that + + + align:start position:0% +repeated and requiring that those that +are on both the left-hand side and the + + align:start position:0% +are on both the left-hand side and the + + + align:start position:0% +are on both the left-hand side and the +right-hand side appear and equal one + + align:start position:0% +right-hand side appear and equal one + + + align:start position:0% +right-hand side appear and equal one +another or + + align:start position:0% +another or + + + align:start position:0% +another or +there's an old professor mind like to + + align:start position:0% +there's an old professor mind like to + + + align:start position:0% +there's an old professor mind like to +say about 12 times a lecture line up the + + align:start position:0% +say about 12 times a lecture line up the + + + align:start position:0% +say about 12 times a lecture line up the +indices so + + align:start position:0% + + + + align:start position:0% + +that's essentially we're doing okay in + + align:start position:0% +that's essentially we're doing okay in + + + align:start position:0% +that's essentially we're doing okay in +this case I line up you know if I have + + align:start position:0% +this case I line up you know if I have + + + align:start position:0% +this case I line up you know if I have +my Lorentz transformation matrix with + + align:start position:0% +my Lorentz transformation matrix with + + + align:start position:0% +my Lorentz transformation matrix with +the bharden X up top and the unbarred + + align:start position:0% +the bharden X up top and the unbarred + + + align:start position:0% +the bharden X up top and the unbarred +down below boom I'll add the indices and + + align:start position:0% +down below boom I'll add the indices and + + + align:start position:0% +down below boom I'll add the indices and +that tells me what the unbarred basis + + align:start position:0% +that tells me what the unbarred basis + + + align:start position:0% +that tells me what the unbarred basis +components are from the bard once and + + align:start position:0% +components are from the bard once and + + + align:start position:0% +components are from the bard once and +vice versa for the components so + + align:start position:0% +vice versa for the components so + + + align:start position:0% +vice versa for the components so +with that basically as I just said that + + align:start position:0% +with that basically as I just said that + + + align:start position:0% +with that basically as I just said that +tells me if I actually want to get this + + align:start position:0% +tells me if I actually want to get this + + + align:start position:0% +tells me if I actually want to get this +guy given this guy I need to work with + + align:start position:0% +guy given this guy I need to work with + + + align:start position:0% +guy given this guy I need to work with +the inverse but + + align:start position:0% +the inverse but + + + align:start position:0% +the inverse but +there's a high so everyone in the back + + align:start position:0% +there's a high so everyone in the back + + + align:start position:0% +there's a high so everyone in the back +and see it so + + align:start position:0% + + + + align:start position:0% + +this + + align:start position:0% +this + + + align:start position:0% +this +again is one of those places where you + + align:start position:0% +again is one of those places where you + + + align:start position:0% +again is one of those places where you +might be tempted right out + + align:start position:0% +might be tempted right out + + + align:start position:0% +might be tempted right out +of matrix and do a matrix inversion but + + align:start position:0% +of matrix and do a matrix inversion but + + + align:start position:0% +of matrix and do a matrix inversion but +before you do that remember this is + + align:start position:0% +before you do that remember this is + + + align:start position:0% +before you do that remember this is +physics okay the inverse is going to be + + align:start position:0% +physics okay the inverse is going to be + + + align:start position:0% +physics okay the inverse is going to be +the inverse matrix is going to be the + + align:start position:0% +the inverse matrix is going to be the + + + align:start position:0% +the inverse matrix is going to be the +one that does at least for certain + + align:start position:0% +one that does at least for certain + + + align:start position:0% +one that does at least for certain +quantities you know what what the what + + align:start position:0% +quantities you know what what the what + + + align:start position:0% +quantities you know what what the what +the Lorentz transformation does that it + + align:start position:0% +the Lorentz transformation does that it + + + align:start position:0% +the Lorentz transformation does that it +relates objects if I'm at rest if I + + align:start position:0% +relates objects if I'm at rest if I + + + align:start position:0% +relates objects if I'm at rest if I +consider myself at rest it tells me + + align:start position:0% +consider myself at rest it tells me + + + align:start position:0% +consider myself at rest it tells me +about things according to a frame that + + align:start position:0% +about things according to a frame that + + + align:start position:0% +about things according to a frame that +is moving with respect to me the inverse + + align:start position:0% +is moving with respect to me the inverse + + + align:start position:0% +is moving with respect to me the inverse +matrix does the opposite it would say to + + align:start position:0% +matrix does the opposite it would say to + + + align:start position:0% +matrix does the opposite it would say to +that person being at rest what the what + + align:start position:0% +that person being at rest what the what + + + align:start position:0% +that person being at rest what the what +is the matrix that tells them about + + align:start position:0% +is the matrix that tells them about + + + align:start position:0% +is the matrix that tells them about +things according to me and they see me + + align:start position:0% +things according to me and they see me + + + align:start position:0% +things according to me and they see me +moving with the exact same velocity but + + align:start position:0% +moving with the exact same velocity but + + + align:start position:0% +moving with the exact same velocity but +in the opposite direction so + + align:start position:0% +in the opposite direction so + + + align:start position:0% +in the opposite direction so +to get the inverse matrix to get the + + align:start position:0% +to get the inverse matrix to get the + + + align:start position:0% +to get the inverse matrix to get the +inverse Lorentz transformation what + + align:start position:0% + + + + align:start position:0% + +we end up doing is we just reverse the + + align:start position:0% +we end up doing is we just reverse the + + + align:start position:0% +we end up doing is we just reverse the +velocity okay + + align:start position:0% + + + + align:start position:0% + +so I have just wrote down for you and + + align:start position:0% +so I have just wrote down for you and + + + align:start position:0% +so I have just wrote down for you and +it's worth bearing in mind every one of + + align:start position:0% +it's worth bearing in mind every one of + + + align:start position:0% +it's worth bearing in mind every one of +these lambdas that it's there they are + + align:start position:0% +these lambdas that it's there they are + + + align:start position:0% +these lambdas that it's there they are +really functions right so my e alpha + + align:start position:0% +really functions right so my e alpha + + + align:start position:0% +really functions right so my e alpha +that I wrote down over there + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +I'm gonna use an under tilde to denote a + + align:start position:0% +I'm gonna use an under tilde to denote a + + + align:start position:0% +I'm gonna use an under tilde to denote a +three factor okay + + align:start position:0% +three factor okay + + + align:start position:0% +three factor okay +in money for textbooks it's written with + + align:start position:0% +in money for textbooks it's written with + + + align:start position:0% +in money for textbooks it's written with +a boldface but that's hard to do on a + + align:start position:0% +a boldface but that's hard to do on a + + + align:start position:0% +a boldface but that's hard to do on a +blackboard okay so if I want to go the + + align:start position:0% +blackboard okay so if I want to go the + + + align:start position:0% +blackboard okay so if I want to go the +other direction well I just need to move + + align:start position:0% +other direction well I just need to move + + + align:start position:0% +other direction well I just need to move +the have the inverse transformation okay + + align:start position:0% + + + + align:start position:0% + +and I have that bear in mind I mean + + align:start position:0% +and I have that bear in mind I mean + + + align:start position:0% +and I have that bear in mind I mean +those are really the exact same matrices + + align:start position:0% +those are really the exact same matrices + + + align:start position:0% +those are really the exact same matrices +okay in terms of the function that I'm + + align:start position:0% +okay in terms of the function that I'm + + + align:start position:0% +okay in terms of the function that I'm +working with here I'm just flipping + + align:start position:0% +working with here I'm just flipping + + + align:start position:0% +working with here I'm just flipping +around the direction we're to get these + + align:start position:0% +around the direction we're to get these + + + align:start position:0% +around the direction we're to get these +things out okay so as + + align:start position:0% + + + + align:start position:0% + +I said you might be tempted just to go + + align:start position:0% +I said you might be tempted just to go + + + align:start position:0% +I said you might be tempted just to go +ahead and do the + + align:start position:0% +ahead and do the + + + align:start position:0% +ahead and do the +matrix inversion let + + align:start position:0% +matrix inversion let + + + align:start position:0% +matrix inversion let +me just do a quick calculation to show + + align:start position:0% +me just do a quick calculation to show + + + align:start position:0% +me just do a quick calculation to show +you that that would work okay + + align:start position:0% +you that that would work okay + + + align:start position:0% +you that that would work okay +and the reason I'm doing this is I just + + align:start position:0% +and the reason I'm doing this is I just + + + align:start position:0% +and the reason I'm doing this is I just +want to quickly step through a + + align:start position:0% +want to quickly step through a + + + align:start position:0% +want to quickly step through a +particular step which is again sort of + + align:start position:0% +particular step which is again sort of + + + align:start position:0% +particular step which is again sort of +in the spirit of swatting mosquitoes + + align:start position:0% +in the spirit of swatting mosquitoes + + + align:start position:0% +in the spirit of swatting mosquitoes +with sledgehammers it's the kind of + + align:start position:0% +with sledgehammers it's the kind of + + + align:start position:0% +with sledgehammers it's the kind of +analysis that you're going to sort of + + align:start position:0% +analysis that you're going to sort of + + + align:start position:0% +analysis that you're going to sort of +have to do off to the side and now and + + align:start position:0% +have to do off to the side and now and + + + align:start position:0% +have to do off to the side and now and +again so + + align:start position:0% +again so + + + align:start position:0% +again so +given that I + + align:start position:0% +given that I + + + align:start position:0% +given that I +know a Alpha is let's see let's use beta + + align:start position:0% +know a Alpha is let's see let's use beta + + + align:start position:0% +know a Alpha is let's see let's use beta +beta + + align:start position:0% +beta + + + align:start position:0% +beta +bar the + + align:start position:0% +bar the + + + align:start position:0% +bar the +beta + + align:start position:0% +beta + + + align:start position:0% +beta +bar but I now know that I could write + + align:start position:0% +bar but I now know that I could write + + + align:start position:0% +bar but I now know that I could write +this + + align:start position:0% + + + + align:start position:0% + +guy as lambda she's a gamma beta + + align:start position:0% +guy as lambda she's a gamma beta + + + align:start position:0% +guy as lambda she's a gamma beta +bar minus + + align:start position:0% +bar minus + + + align:start position:0% +bar minus +V you + + align:start position:0% +V you + + + align:start position:0% +V you +have a direction now you look at that + + align:start position:0% +have a direction now you look at that + + + align:start position:0% +have a direction now you look at that +and you go oh look I'm actually summing + + align:start position:0% +and you go oh look I'm actually summing + + + align:start position:0% +and you go oh look I'm actually summing +over the betas there let's gather my + + align:start position:0% +over the betas there let's gather my + + + align:start position:0% +over the betas there let's gather my +terms a little bit differently + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +notice I have unbarred basis vectors + + align:start position:0% +notice I have unbarred basis vectors + + + align:start position:0% +notice I have unbarred basis vectors +over here on the Left unbarred ones over + + align:start position:0% +over here on the Left unbarred ones over + + + align:start position:0% +over here on the Left unbarred ones over +here on the right a bunch of junk in + + align:start position:0% +here on the right a bunch of junk in + + + align:start position:0% +here on the right a bunch of junk in +these braces here in the middle the only + + align:start position:0% +these braces here in the middle the only + + + align:start position:0% +these braces here in the middle the only +way for that to work is if after summing + + align:start position:0% +way for that to work is if after summing + + + align:start position:0% +way for that to work is if after summing +over beta that bunch of junk is in + + align:start position:0% +over beta that bunch of junk is in + + + align:start position:0% +over beta that bunch of junk is in +matrix language we would say it's the + + align:start position:0% +matrix language we would say it's the + + + align:start position:0% +matrix language we would say it's the +identity matrix okay in component + + align:start position:0% +identity matrix okay in component + + + align:start position:0% +identity matrix okay in component +notation we're gonna call it the + + align:start position:0% +notation we're gonna call it the + + + align:start position:0% +notation we're gonna call it the +Kronecker Delta + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +just + + align:start position:0% +just + + + align:start position:0% +just +[Applause] + + align:start position:0% + + + + align:start position:0% + +as a little aside if I started with the + + align:start position:0% +as a little aside if I started with the + + + align:start position:0% +as a little aside if I started with the +bard on the left side and the unbarred + + align:start position:0% +bard on the left side and the unbarred + + + align:start position:0% +bard on the left side and the unbarred +in the right hand side and did a similar + + align:start position:0% +in the right hand side and did a similar + + + align:start position:0% +in the right hand side and did a similar +analysis it would take you at this point + + align:start position:0% +analysis it would take you at this point + + + align:start position:0% +analysis it would take you at this point +now that you are all fully + + align:start position:0% + + + + align:start position:0% + +expert in this kind of index + + align:start position:0% +expert in this kind of index + + + align:start position:0% +expert in this kind of index +manipulation it + + align:start position:0% +manipulation it + + + align:start position:0% +manipulation it +should take you no more than about a + + align:start position:0% +should take you no more than about a + + + align:start position:0% +should take you no more than about a +minute to demonstrate to yourself that + + align:start position:0% +minute to demonstrate to yourself that + + + align:start position:0% +minute to demonstrate to yourself that +you + + align:start position:0% +you + + + align:start position:0% +you +can get a chronic + + align:start position:0% + + + + align:start position:0% + +or Delta on the bard indices in a + + align:start position:0% +or Delta on the bard indices in a + + + align:start position:0% +or Delta on the bard indices in a +similar way just by using them in a + + align:start position:0% +similar way just by using them in a + + + align:start position:0% +similar way just by using them in a +slightly different order okay alright so + + align:start position:0% +slightly different order okay alright so + + + align:start position:0% +slightly different order okay alright so +far + + align:start position:0% +far + + + align:start position:0% +far +all still basically just formalism so + + align:start position:0% +all still basically just formalism so + + + align:start position:0% +all still basically just formalism so +I'm gonna start now doing a little bit + + align:start position:0% +I'm gonna start now doing a little bit + + + align:start position:0% +I'm gonna start now doing a little bit +of formalism that will + + align:start position:0% +of formalism that will + + + align:start position:0% +of formalism that will +very quickly sag into physics we can all + + align:start position:0% +very quickly sag into physics we can all + + + align:start position:0% +very quickly sag into physics we can all +take a deep sigh of relief and go ah + + align:start position:0% +take a deep sigh of relief and go ah + + + align:start position:0% +take a deep sigh of relief and go ah +okay something you can imagine measuring + + align:start position:0% +okay something you can imagine measuring + + + align:start position:0% +okay something you can imagine measuring +so that's nice so + + align:start position:0% +so that's nice so + + + align:start position:0% +so that's nice so +I have + + align:start position:0% +I have + + + align:start position:0% +I have +introduced four vectors I have + + align:start position:0% +introduced four vectors I have + + + align:start position:0% +introduced four vectors I have +introduced the basis vectors and their + + align:start position:0% +introduced the basis vectors and their + + + align:start position:0% +introduced the basis vectors and their +components I've really done anything + + align:start position:0% +components I've really done anything + + + align:start position:0% +components I've really done anything +with them yet so + + align:start position:0% +with them yet so + + + align:start position:0% +with them yet so +before we start doing things with them + + align:start position:0% +before we start doing things with them + + + align:start position:0% +before we start doing things with them +let's think about some operations that + + align:start position:0% +let's think about some operations that + + + align:start position:0% +let's think about some operations that +we can do with four vectors so the first + + align:start position:0% +we can do with four vectors so the first + + + align:start position:0% +we can do with four vectors so the first +one which I would like to introduce is a + + align:start position:0% +one which I would like to introduce is a + + + align:start position:0% +one which I would like to introduce is a +scalar product to + + align:start position:0% + + + + align:start position:0% + +motivate the scalar product that I'm + + align:start position:0% +motivate the scalar product that I'm + + + align:start position:0% +motivate the scalar product that I'm +going to define in the same way that I + + align:start position:0% +going to define in the same way that I + + + align:start position:0% +going to define in the same way that I +defined for vectors as a quartet of + + align:start position:0% +defined for vectors as a quartet of + + + align:start position:0% +defined for vectors as a quartet of +numbers whose transformation properties + + align:start position:0% +numbers whose transformation properties + + + align:start position:0% +numbers whose transformation properties +are based on the transformation + + align:start position:0% +are based on the transformation + + + align:start position:0% +are based on the transformation +properties of the displacement I'm going + + align:start position:0% +properties of the displacement I'm going + + + align:start position:0% +properties of the displacement I'm going +to motivate a general scalar product + + align:start position:0% +to motivate a general scalar product + + + align:start position:0% +to motivate a general scalar product +between four vectors by a similar kind + + align:start position:0% +between four vectors by a similar kind + + + align:start position:0% +between four vectors by a similar kind +of quantity that is constructed from the + + align:start position:0% +of quantity that is constructed from the + + + align:start position:0% +of quantity that is constructed from the +displacement so let me recall a result + + align:start position:0% +displacement so let me recall a result + + + align:start position:0% +displacement so let me recall a result +that I hope is familiar from special + + align:start position:0% +that I hope is familiar from special + + + align:start position:0% +that I hope is familiar from special +relativity + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +working in units where the speed of + + align:start position:0% +working in units where the speed of + + + align:start position:0% +working in units where the speed of +light is one you + + align:start position:0% + + + + align:start position:0% + +are hopefully all familiar at the fact + + align:start position:0% +are hopefully all familiar at the fact + + + align:start position:0% +are hopefully all familiar at the fact +that this quantity is something that is + + align:start position:0% +that this quantity is something that is + + + align:start position:0% +that this quantity is something that is +invariance to all observers I really I + + align:start position:0% +invariance to all observers I really I + + + align:start position:0% +invariance to all observers I really I +did not use a represented by symbol + + align:start position:0% +did not use a represented by symbol + + + align:start position:0% +did not use a represented by symbol +there because no matter whose Delta T + + align:start position:0% +there because no matter whose Delta T + + + align:start position:0% +there because no matter whose Delta T +Delta X Delta Y Delta Z I use there they + + align:start position:0% +Delta X Delta Y Delta Z I use there they + + + align:start position:0% +Delta X Delta Y Delta Z I use there they +will all agree on the Delta s squared + + align:start position:0% +will all agree on the Delta s squared + + + align:start position:0% +will all agree on the Delta s squared +that comes out of us okay if I want to + + align:start position:0% +that comes out of us okay if I want to + + + align:start position:0% +that comes out of us okay if I want to +actually want me to write a few things + + align:start position:0% +actually want me to write a few things + + + align:start position:0% +actually want me to write a few things +down before I even think more so this is + + align:start position:0% +down before I even think more so this is + + + align:start position:0% +down before I even think more so this is +an invariant this + + align:start position:0% + + + + align:start position:0% + +is the same different + + align:start position:0% + + + + align:start position:0% + +way it is the same in all Lorentz frames + + align:start position:0% +way it is the same in all Lorentz frames + + + align:start position:0% +way it is the same in all Lorentz frames +so + + align:start position:0% + + + + align:start position:0% + +pick some observer get their delta T + + align:start position:0% +pick some observer get their delta T + + + align:start position:0% +pick some observer get their delta T +Delta X etc assemble + + align:start position:0% +Delta X etc assemble + + + align:start position:0% +Delta X etc assemble +Delta s squared pick a different + + align:start position:0% +Delta s squared pick a different + + + align:start position:0% +Delta s squared pick a different +observer do de Lorentz transformation + + align:start position:0% +observer do de Lorentz transformation + + + align:start position:0% +observer do de Lorentz transformation +assemble their delta T prime Delta X + + align:start position:0% +assemble their delta T prime Delta X + + + align:start position:0% +assemble their delta T prime Delta X +prime etc make that boom they all agree + + align:start position:0% +prime etc make that boom they all agree + + + align:start position:0% +prime etc make that boom they all agree +so we're going to use this to say you + + align:start position:0% +so we're going to use this to say you + + + align:start position:0% +so we're going to use this to say you +know what I'm gonna call that the + + align:start position:0% +know what I'm gonna call that the + + + align:start position:0% +know what I'm gonna call that the +inner product of the displacement vector + + align:start position:0% +inner product of the displacement vector + + + align:start position:0% +inner product of the displacement vector +with itself so + + align:start position:0% + + + + align:start position:0% + +I'm going to call this Delta + + align:start position:0% +I'm going to call this Delta + + + align:start position:0% +I'm going to call this Delta +X dot it into Delta X ok so what this + + align:start position:0% +X dot it into Delta X ok so what this + + + align:start position:0% +X dot it into Delta X ok so what this +means is that built into my scalar + + align:start position:0% +means is that built into my scalar + + + align:start position:0% +means is that built into my scalar +product so + + align:start position:0% +product so + + + align:start position:0% +product so +if I write this as a particular observer + + align:start position:0% +if I write this as a particular observer + + + align:start position:0% +if I write this as a particular observer +would compute + + align:start position:0% + + + + align:start position:0% + +this + + align:start position:0% + + + + align:start position:0% + +is the scalar product that I'm going to + + align:start position:0% +is the scalar product that I'm going to + + + align:start position:0% +is the scalar product that I'm going to +define with respect to the displacement + + align:start position:0% +define with respect to the displacement + + + align:start position:0% +define with respect to the displacement +factor and this is usually the point + + align:start position:0% +factor and this is usually the point + + + align:start position:0% +factor and this is usually the point +where somebody in the class is thinking + + align:start position:0% +where somebody in the class is thinking + + + align:start position:0% +where somebody in the class is thinking +why is there a minus sign in front of + + align:start position:0% +why is there a minus sign in front of + + + align:start position:0% +why is there a minus sign in front of +the time like piece I can't + + align:start position:0% + + + + align:start position:0% + +answer that all I can say is that + + align:start position:0% +answer that all I can say is that + + + align:start position:0% +answer that all I can say is that +appears to be more than appears to be + + align:start position:0% +appears to be more than appears to be + + + align:start position:0% +appears to be more than appears to be +there's a whole freaking buttload of + + align:start position:0% +there's a whole freaking buttload of + + + align:start position:0% +there's a whole freaking buttload of +evidence it says how nature is assembled + + align:start position:0% +evidence it says how nature is assembled + + + align:start position:0% +evidence it says how nature is assembled +okay it's connected to the fact so the + + align:start position:0% +okay it's connected to the fact so the + + + align:start position:0% +okay it's connected to the fact so the +fact that all of my spatial directions + + align:start position:0% +fact that all of my spatial directions + + + align:start position:0% +fact that all of my spatial directions +are sort of entually the same sign but + + align:start position:0% +are sort of entually the same sign but + + + align:start position:0% +are sort of entually the same sign but +my time light direction is moving it has + + align:start position:0% +my time light direction is moving it has + + + align:start position:0% +my time light direction is moving it has +a different sign it's connected to the + + align:start position:0% +a different sign it's connected to the + + + align:start position:0% +a different sign it's connected to the +fact that I can easily move left and + + align:start position:0% +fact that I can easily move left and + + + align:start position:0% +fact that I can easily move left and +right front and back a little bit of + + align:start position:0% +right front and back a little bit of + + + align:start position:0% +right front and back a little bit of +effort I can move up and down but I + + align:start position:0% +effort I can move up and down but I + + + align:start position:0% +effort I can move up and down but I +cannot say oh crap I left my phone at + + align:start position:0% +cannot say oh crap I left my phone at + + + align:start position:0% +cannot say oh crap I left my phone at +home I'll go back fifteen minutes and + + align:start position:0% +home I'll go back fifteen minutes and + + + align:start position:0% +home I'll go back fifteen minutes and +pick it up right you cannot move back + + align:start position:0% +pick it up right you cannot move back + + + align:start position:0% +pick it up right you cannot move back +and forth in time time actually which is + + align:start position:0% +and forth in time time actually which is + + + align:start position:0% +and forth in time time actually which is +the time light component of this thing + + align:start position:0% +the time light component of this thing + + + align:start position:0% +the time light component of this thing +it enters into the geometry in a + + align:start position:0% +it enters into the geometry in a + + + align:start position:0% +it enters into the geometry in a +fundamentally different way from the + + align:start position:0% +fundamentally different way from the + + + align:start position:0% +fundamentally different way from the +spatial things and that's reflected in + + align:start position:0% +spatial things and that's reflected in + + + align:start position:0% +spatial things and that's reflected in +that minus sign anything + + align:start position:0% +that minus sign anything + + + align:start position:0% +that minus sign anything +deeper than that let's + + align:start position:0% +deeper than that let's + + + align:start position:0% +deeper than that let's +just say that we're probably not likely + + align:start position:0% +just say that we're probably not likely + + + align:start position:0% +just say that we're probably not likely +to get very far at that conversation + + align:start position:0% +to get very far at that conversation + + + align:start position:0% +to get very far at that conversation +depending on what kind of muscle + + align:start position:0% +depending on what kind of muscle + + + align:start position:0% +depending on what kind of muscle +relaxants you enjoy using on the weekend + + align:start position:0% +relaxants you enjoy using on the weekend + + + align:start position:0% +relaxants you enjoy using on the weekend +you might have some fun conversations + + align:start position:0% +you might have some fun conversations + + + align:start position:0% +you might have some fun conversations +about it but it is not something that + + align:start position:0% +about it but it is not something that + + + align:start position:0% +about it but it is not something that +you're really going to get very far with + + align:start position:0% +you're really going to get very far with + + + align:start position:0% +you're really going to get very far with +you just kind of have to accept it it's + + align:start position:0% +you just kind of have to accept it it's + + + align:start position:0% +you just kind of have to accept it it's +part of the built in geometry of nature + + align:start position:0% +part of the built in geometry of nature + + + align:start position:0% +part of the built in geometry of nature +okay + + align:start position:0% + + + + align:start position:0% + +so this I am defining as the inner + + align:start position:0% +so this I am defining as the inner + + + align:start position:0% +so this I am defining as the inner +product with the of the displacement + + align:start position:0% +product with the of the displacement + + + align:start position:0% +product with the of the displacement +vector with itself i define vectors as + + align:start position:0% +vector with itself i define vectors as + + + align:start position:0% +vector with itself i define vectors as +having the same transformation property + + align:start position:0% +having the same transformation property + + + align:start position:0% +having the same transformation property +as the displacement vector + + align:start position:0% + + + + align:start position:0% + +we + + align:start position:0% + + + + align:start position:0% + +can similarly define an inner product of + + align:start position:0% +can similarly define an inner product of + + + align:start position:0% +can similarly define an inner product of +a four vector with itself another + + align:start position:0% + + + + align:start position:0% + +board a dot + + align:start position:0% +board a dot + + + align:start position:0% +board a dot +[Applause] + + align:start position:0% + + + + align:start position:0% + +a I'm + + align:start position:0% + + + + align:start position:0% + +going to define this or rather I will + + align:start position:0% +going to define this or rather I will + + + align:start position:0% +going to define this or rather I will +say it is represented according to + + align:start position:0% +say it is represented according to + + + align:start position:0% +say it is represented according to +observer o as + + align:start position:0% + + + + align:start position:0% + +minus a0 + + align:start position:0% +minus a0 + + + align:start position:0% +minus a0 +squared plus + + align:start position:0% +squared plus + + + align:start position:0% +squared plus +a1 squared plus + + align:start position:0% +a1 squared plus + + + align:start position:0% +a1 squared plus +a2 squared plus a3 + + align:start position:0% +a2 squared plus a3 + + + align:start position:0% +a2 squared plus a3 +squared okay + + align:start position:0% +squared okay + + + align:start position:0% +squared okay +I realize there can be a little bit of + + align:start position:0% +I realize there can be a little bit of + + + align:start position:0% +I realize there can be a little bit of +ambiguity in the way I'm writing it here + + align:start position:0% +ambiguity in the way I'm writing it here + + + align:start position:0% +ambiguity in the way I'm writing it here +I you just have to if you ever confused + + align:start position:0% +I you just have to if you ever confused + + + align:start position:0% +I you just have to if you ever confused +just ask for clarification about whether + + align:start position:0% +just ask for clarification about whether + + + align:start position:0% +just ask for clarification about whether +I'm raising something to a power or + + align:start position:0% +I'm raising something to a power or + + + align:start position:0% +I'm raising something to a power or +whether it's an index label contacts + + align:start position:0% +whether it's an index label contacts + + + align:start position:0% +whether it's an index label contacts +usually makes it clear handwriting + + align:start position:0% +usually makes it clear handwriting + + + align:start position:0% +usually makes it clear handwriting +sometimes excuse contacts + + align:start position:0% +sometimes excuse contacts + + + align:start position:0% +sometimes excuse contacts +though the reason why I'm doing this and + + align:start position:0% +though the reason why I'm doing this and + + + align:start position:0% +though the reason why I'm doing this and +a real benefit of this is that whatever + + align:start position:0% +a real benefit of this is that whatever + + + align:start position:0% +a real benefit of this is that whatever +this quantity is because a has the same + + align:start position:0% +this quantity is because a has the same + + + align:start position:0% +this quantity is because a has the same +transformation properties of the + + align:start position:0% +transformation properties of the + + + align:start position:0% +transformation properties of the +displacement this must be a Lorentz + + align:start position:0% +displacement this must be a Lorentz + + + align:start position:0% +displacement this must be a Lorentz +invariant as well + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +the underlying mathematics of Lorentz + + align:start position:0% +the underlying mathematics of Lorentz + + + align:start position:0% +the underlying mathematics of Lorentz +transformation doesn't care that I wrote + + align:start position:0% +transformation doesn't care that I wrote + + + align:start position:0% +transformation doesn't care that I wrote +a zero instead of Delta X here it + + align:start position:0% +a zero instead of Delta X here it + + + align:start position:0% +a zero instead of Delta X here it +doesn't care that I wrote a 1 instead of + + align:start position:0% +doesn't care that I wrote a 1 instead of + + + align:start position:0% +doesn't care that I wrote a 1 instead of +Delta X 1 etc okay it just knows that + + align:start position:0% +Delta X 1 etc okay it just knows that + + + align:start position:0% +Delta X 1 etc okay it just knows that +it's a thing that goes into that slot of + + align:start position:0% +it's a thing that goes into that slot of + + + align:start position:0% +it's a thing that goes into that slot of +Lorentz transformation so all observers + + align:start position:0% +Lorentz transformation so all observers + + + align:start position:0% +Lorentz transformation so all observers +this is how I represent it according to + + align:start position:0% +this is how I represent it according to + + + align:start position:0% +this is how I represent it according to +observer oh but all observers agree on + + align:start position:0% +observer oh but all observers agree on + + + align:start position:0% +observer oh but all observers agree on +that form um and as a consequence this + + align:start position:0% +that form um and as a consequence this + + + align:start position:0% +that form um and as a consequence this +is gonna be something that we exploit a + + align:start position:0% +is gonna be something that we exploit a + + + align:start position:0% +is gonna be something that we exploit a +lot ok even when we move beyond the sort + + align:start position:0% +lot ok even when we move beyond the sort + + + align:start position:0% +lot ok even when we move beyond the sort +of the simple geometry of special + + align:start position:0% +of the simple geometry of special + + + align:start position:0% +of the simple geometry of special +relativity a generalization of this will + + align:start position:0% +relativity a generalization of this will + + + align:start position:0% +relativity a generalization of this will +be extremely important for not an + + align:start position:0% +be extremely important for not an + + + align:start position:0% +be extremely important for not an +exaggeration to say everything so + + align:start position:0% +exaggeration to say everything so + + + align:start position:0% +exaggeration to say everything so +a little bit of terminology so + + align:start position:0% + + + + align:start position:0% + +if a dot + + align:start position:0% +if a dot + + + align:start position:0% +if a dot +a is negative and depending upon which + + align:start position:0% +a is negative and depending upon which + + + align:start position:0% +a is negative and depending upon which +is bigger a zero squared or the some of + + align:start position:0% +is bigger a zero squared or the some of + + + align:start position:0% +is bigger a zero squared or the some of +the other ones could very well be + + align:start position:0% +the other ones could very well be + + + align:start position:0% +the other ones could very well be +negative we say that a is a time like + + align:start position:0% +negative we say that a is a time like + + + align:start position:0% +negative we say that a is a time like +vector ok + + align:start position:0% + + + + align:start position:0% + +there's traces back to the fact that if + + align:start position:0% +there's traces back to the fact that if + + + align:start position:0% +there's traces back to the fact that if +a were the displacement vector if the + + align:start position:0% +a were the displacement vector if the + + + align:start position:0% +a were the displacement vector if the +displacement the invariant interval were + + align:start position:0% +displacement the invariant interval were + + + align:start position:0% +displacement the invariant interval were +negative that would tell me that the two + + align:start position:0% +negative that would tell me that the two + + + align:start position:0% +negative that would tell me that the two +events which are the beginning in the + + align:start position:0% +events which are the beginning in the + + + align:start position:0% +events which are the beginning in the +end of the interval I could find a frame + + align:start position:0% +end of the interval I could find a frame + + + align:start position:0% +end of the interval I could find a frame +at which they are at the exact same + + align:start position:0% +at which they are at the exact same + + + align:start position:0% +at which they are at the exact same +location and are only separated in time + + align:start position:0% +location and are only separated in time + + + align:start position:0% +location and are only separated in time +ok in the same way this is basically + + align:start position:0% +ok in the same way this is basically + + + align:start position:0% +ok in the same way this is basically +saying that I can find a frame where + + align:start position:0% +saying that I can find a frame where + + + align:start position:0% +saying that I can find a frame where +this vector points parallel to observer + + align:start position:0% +this vector points parallel to observer + + + align:start position:0% +this vector points parallel to observer +at some observers time axis this + + align:start position:0% + + + + align:start position:0% + +is positive a is + + align:start position:0% +is positive a is + + + align:start position:0% +is positive a is +spaced + + align:start position:0% +spaced + + + align:start position:0% +spaced +like + + align:start position:0% + + + + align:start position:0% + +everything I just said about time like + + align:start position:0% +everything I just said about time like + + + align:start position:0% +everything I just said about time like +lather rinse repeat but replace time + + align:start position:0% +lather rinse repeat but replace time + + + align:start position:0% +lather rinse repeat but replace time +with space good and + + align:start position:0% + + + + align:start position:0% + +if a dot a equals zero we + + align:start position:0% +if a dot a equals zero we + + + align:start position:0% +if a dot a equals zero we +say a is there's two words that are + + align:start position:0% +say a is there's two words that are + + + align:start position:0% +say a is there's two words that are +commonly used lights + + align:start position:0% +commonly used lights + + + align:start position:0% +commonly used lights +like or + + align:start position:0% +like or + + + align:start position:0% +like or +no + + align:start position:0% +no + + + align:start position:0% +no +null + + align:start position:0% +null + + + align:start position:0% +null +just traces back obviously to the zero + + align:start position:0% +just traces back obviously to the zero + + + align:start position:0% +just traces back obviously to the zero +light like is because this is a vector + + align:start position:0% +light like is because this is a vector + + + align:start position:0% +light like is because this is a vector +that could lie tangent to the trajectory + + align:start position:0% +that could lie tangent to the trajectory + + + align:start position:0% +that could lie tangent to the trajectory +that a light beam follows in space in + + align:start position:0% +that a light beam follows in space in + + + align:start position:0% +that a light beam follows in space in +space-time + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +get some clean shock so + + align:start position:0% + + + + align:start position:0% + +so far I've only talked about this inner + + align:start position:0% +so far I've only talked about this inner + + + align:start position:0% +so far I've only talked about this inner +product this scalar product oh and by + + align:start position:0% +product this scalar product oh and by + + + align:start position:0% +product this scalar product oh and by +the way so with this we will often I'll + + align:start position:0% +the way so with this we will often I'll + + + align:start position:0% +the way so with this we will often I'll +use inner product and scalar product + + align:start position:0% +use inner product and scalar product + + + align:start position:0% +use inner product and scalar product +somewhat + + align:start position:0% +somewhat + + + align:start position:0% +somewhat +interchangeably but this allows me to + + align:start position:0% +interchangeably but this allows me to + + + align:start position:0% +interchangeably but this allows me to +reiterate a point I made in Tuesday's + + align:start position:0% +reiterate a point I made in Tuesday's + + + align:start position:0% +reiterate a point I made in Tuesday's +lecture when I say scalar scalar refers + + align:start position:0% +lecture when I say scalar scalar refers + + + align:start position:0% +lecture when I say scalar scalar refers +to a quantity which is it doesn't many + + align:start position:0% +to a quantity which is it doesn't many + + + align:start position:0% +to a quantity which is it doesn't many +components associated with it so in that + + align:start position:0% +components associated with it so in that + + + align:start position:0% +components associated with it so in that +sense it's familiar from your your + + align:start position:0% +sense it's familiar from your your + + + align:start position:0% +sense it's familiar from your your +intuition of you know not a vector but + + align:start position:0% +intuition of you know not a vector but + + + align:start position:0% +intuition of you know not a vector but +it has a deeper meaning in this course + + align:start position:0% +it has a deeper meaning in this course + + + align:start position:0% +it has a deeper meaning in this course +because I also want to be something that + + align:start position:0% +because I also want to be something that + + + align:start position:0% +because I also want to be something that +is invariant between reference frames so + + align:start position:0% +is invariant between reference frames so + + + align:start position:0% +is invariant between reference frames so +a dot a is the scalar product gives me a + + align:start position:0% +a dot a is the scalar product gives me a + + + align:start position:0% +a dot a is the scalar product gives me a +quantity that all observers agree on now + + align:start position:0% +quantity that all observers agree on now + + + align:start position:0% +quantity that all observers agree on now +I've only done scalar products of + + align:start position:0% +I've only done scalar products of + + + align:start position:0% +I've only done scalar products of +vectors and the displacement factor with + + align:start position:0% +vectors and the displacement factor with + + + align:start position:0% +vectors and the displacement factor with +themselves so a more general notion if + + align:start position:0% + + + + align:start position:0% + +I have vectors a and B then + + align:start position:0% + + + + align:start position:0% + +I will define the inner product between + + align:start position:0% +I will define the inner product between + + + align:start position:0% +I will define the inner product between +them as observed by oh that's + + align:start position:0% +them as observed by oh that's + + + align:start position:0% +them as observed by oh that's +constructed by observer oh rather like + + align:start position:0% +constructed by observer oh rather like + + + align:start position:0% +constructed by observer oh rather like +so okay + + align:start position:0% + + + + align:start position:0% + +it's not hard to convince yourself given + + align:start position:0% +it's not hard to convince yourself given + + + align:start position:0% +it's not hard to convince yourself given +everything we've done so far that this + + align:start position:0% +everything we've done so far that this + + + align:start position:0% +everything we've done so far that this +quantity must also be invariant I'll + + align:start position:0% +quantity must also be invariant I'll + + + align:start position:0% +quantity must also be invariant I'll +sketch a really quick proof let's + + align:start position:0% + + + + align:start position:0% + +define let's say we have two four + + align:start position:0% +define let's say we have two four + + + align:start position:0% +define let's say we have two four +vectors a and Bing they're + + align:start position:0% +vectors a and Bing they're + + + align:start position:0% +vectors a and Bing they're +some by the linearity rules that apply + + align:start position:0% +some by the linearity rules that apply + + + align:start position:0% +some by the linearity rules that apply +to these vectors must also be a vector + + align:start position:0% +to these vectors must also be a vector + + + align:start position:0% +to these vectors must also be a vector +and so if I compute C + + align:start position:0% +and so if I compute C + + + align:start position:0% +and so if I compute C +dot C this is an invariant with + + align:start position:0% +dot C this is an invariant with + + + align:start position:0% +dot C this is an invariant with +a little bit of + + align:start position:0% + + + + align:start position:0% + +a little bit of labour that + + align:start position:0% +a little bit of labour that + + + align:start position:0% +a little bit of labour that +basically boils down to middle school + + align:start position:0% +basically boils down to middle school + + + align:start position:0% +basically boils down to middle school +algebra you can show that C dot C is a + + align:start position:0% +algebra you can show that C dot C is a + + + align:start position:0% +algebra you can show that C dot C is a +plus B dot B plus twice a dot B this is + + align:start position:0% +plus B dot B plus twice a dot B this is + + + align:start position:0% +plus B dot B plus twice a dot B this is +invariant this is invariant this is + + align:start position:0% +invariant this is invariant this is + + + align:start position:0% +invariant this is invariant this is +invariant and so this must be invariant + + align:start position:0% +invariant and so this must be invariant + + + align:start position:0% +invariant and so this must be invariant +so + + align:start position:0% + + + + align:start position:0% + +this is really useful for us okay + + align:start position:0% +this is really useful for us okay + + + align:start position:0% +this is really useful for us okay +because we now have a way now I've + + align:start position:0% +because we now have a way now I've + + + align:start position:0% +because we now have a way now I've +introduced these objects these geometric + + align:start position:0% +introduced these objects these geometric + + + align:start position:0% +introduced these objects these geometric +objects these four vectors we are going + + align:start position:0% +objects these four vectors we are going + + + align:start position:0% +objects these four vectors we are going +to use them in this class to describe + + align:start position:0% +to use them in this class to describe + + + align:start position:0% +to use them in this class to describe +quantities that are of interest to the + + align:start position:0% +quantities that are of interest to the + + + align:start position:0% +quantities that are of interest to the +physicist who wants to make measurements + + align:start position:0% +physicist who wants to make measurements + + + align:start position:0% +physicist who wants to make measurements +in space-time we've now learned what + + align:start position:0% +in space-time we've now learned what + + + align:start position:0% +in space-time we've now learned what +other things when you're doing stuff in + + align:start position:0% +other things when you're doing stuff in + + + align:start position:0% +other things when you're doing stuff in +relativity have to be careful who is + + align:start position:0% +relativity have to be careful who is + + + align:start position:0% +relativity have to be careful who is +measuring what okay what are the + + align:start position:0% +measuring what okay what are the + + + align:start position:0% +measuring what okay what are the +compounds that for vector as seen by + + align:start position:0% +compounds that for vector as seen by + + + align:start position:0% +compounds that for vector as seen by +this observer what about their friend + + align:start position:0% +this observer what about their friend + + + align:start position:0% +this observer what about their friend +who's jogging through the room and 3/4 + + align:start position:0% +who's jogging through the room and 3/4 + + + align:start position:0% +who's jogging through the room and 3/4 +beetle light what about their friend + + align:start position:0% +beetle light what about their friend + + + align:start position:0% +beetle light what about their friend +who's dragging at 2/3 P lettin you know + + align:start position:0% +who's dragging at 2/3 P lettin you know + + + align:start position:0% +who's dragging at 2/3 P lettin you know +direction you know you have all these + + align:start position:0% +direction you know you have all these + + + align:start position:0% +direction you know you have all these +really annoying calculations that you + + align:start position:0% +really annoying calculations that you + + + align:start position:0% +really annoying calculations that you +can and sometimes have to do this gives + + align:start position:0% +can and sometimes have to do this gives + + + align:start position:0% +can and sometimes have to do this gives +us a way to get certain things that are + + align:start position:0% +us a way to get certain things that are + + + align:start position:0% +us a way to get certain things that are +invariant out of the situation that + + align:start position:0% +invariant out of the situation that + + + align:start position:0% +invariant out of the situation that +everyone is going to agree on and + + align:start position:0% +everyone is going to agree on and + + + align:start position:0% +everyone is going to agree on and +variance are our friends + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +earlier today earlier in today's lecture + + align:start position:0% +earlier today earlier in today's lecture + + + align:start position:0% +earlier today earlier in today's lecture +I talked about how I can write my four + + align:start position:0% +I talked about how I can write my four + + + align:start position:0% +I talked about how I can write my four +vectors using the basis factors so + + align:start position:0% +vectors using the basis factors so + + + align:start position:0% +vectors using the basis factors so +another way of writing this so know what + + align:start position:0% +another way of writing this so know what + + + align:start position:0% +another way of writing this so know what +sort of annoying is every time I've + + align:start position:0% +sort of annoying is every time I've + + + align:start position:0% +sort of annoying is every time I've +actually written out the inner product I + + align:start position:0% +actually written out the inner product I + + + align:start position:0% +actually written out the inner product I +have used them represented by symbol I + + align:start position:0% +have used them represented by symbol I + + + align:start position:0% +have used them represented by symbol I +don't want that I want to have equal + + align:start position:0% +don't want that I want to have equal + + + align:start position:0% +don't want that I want to have equal +symbols in there damn it so let's + + align:start position:0% +symbols in there damn it so let's + + + align:start position:0% +symbols in there damn it so let's +take advantage of the fact that a big + + align:start position:0% +take advantage of the fact that a big + + + align:start position:0% +take advantage of the fact that a big +I know how to expand a and B using + + align:start position:0% +I know how to expand a and B using + + + align:start position:0% +I know how to expand a and B using +components and basis vectors and + + align:start position:0% + + + + align:start position:0% + +again using the index notation I can + + align:start position:0% +again using the index notation I can + + + align:start position:0% +again using the index notation I can +just pull everything out and rearrange + + align:start position:0% +just pull everything out and rearrange + + + align:start position:0% +just pull everything out and rearrange +this a little bit whenever + + align:start position:0% + + + + align:start position:0% + +you get down to a point like this we now + + align:start position:0% +you get down to a point like this we now + + + align:start position:0% +you get down to a point like this we now +get to do what every mathematician loves + + align:start position:0% +get to do what every mathematician loves + + + align:start position:0% +get to do what every mathematician loves +to do give something a name I'm going to + + align:start position:0% +to do give something a name I'm going to + + + align:start position:0% +to do give something a name I'm going to +define the inner product of basis vector + + align:start position:0% +define the inner product of basis vector + + + align:start position:0% +define the inner product of basis vector +a with basis vector B to + + align:start position:0% +a with basis vector B to + + + align:start position:0% +a with basis vector B to +be a to index tensor ada alpha beta + + align:start position:0% +be a to index tensor ada alpha beta + + + align:start position:0% +be a to index tensor ada alpha beta +which + + align:start position:0% + + + + align:start position:0% + +lovely about this is this is a totally + + align:start position:0% +lovely about this is this is a totally + + + align:start position:0% +lovely about this is this is a totally +frame invariant quantity we know that + + align:start position:0% +frame invariant quantity we know that + + + align:start position:0% +frame invariant quantity we know that +and so I've now found a way to write + + align:start position:0% +and so I've now found a way to write + + + align:start position:0% +and so I've now found a way to write +this using the components as something + + align:start position:0% +this using the components as something + + + align:start position:0% +this using the components as something +that gives me a result that is totally + + align:start position:0% +that gives me a result that is totally + + + align:start position:0% +that gives me a result that is totally +frame invariant now when you hack + + align:start position:0% +frame invariant now when you hack + + + align:start position:0% +frame invariant now when you hack +through a little of the algebra of this + + align:start position:0% +through a little of the algebra of this + + + align:start position:0% +through a little of the algebra of this +what you'll find is that the components + + align:start position:0% +what you'll find is that the components + + + align:start position:0% +what you'll find is that the components +of this metric oh shoot it out loud the + + align:start position:0% +of this metric oh shoot it out loud the + + + align:start position:0% +of this metric oh shoot it out loud the +components of this tensor which I will + + align:start position:0% +components of this tensor which I will + + + align:start position:0% +components of this tensor which I will +pretend you didn't hear me say that the + + align:start position:0% +pretend you didn't hear me say that the + + + align:start position:0% +pretend you didn't hear me say that the +compliance of this tensor has the + + align:start position:0% +compliance of this tensor has the + + + align:start position:0% +compliance of this tensor has the +following components I just + + align:start position:0% +following components I just + + + align:start position:0% +following components I just +answered or had the following values + + align:start position:0% + + + + align:start position:0% + +this + + align:start position:0% + + + + align:start position:0% + +is as I unfortunately gave away the plot + + align:start position:0% +is as I unfortunately gave away the plot + + + align:start position:0% +is as I unfortunately gave away the plot +this is in fact the metric that I set at + + align:start position:0% +this is in fact the metric that I set at + + + align:start position:0% +this is in fact the metric that I set at +the beginning is the quantity that I + + align:start position:0% +the beginning is the quantity that I + + + align:start position:0% +the beginning is the quantity that I +must associate with space-time in order + + align:start position:0% +must associate with space-time in order + + + align:start position:0% +must associate with space-time in order +for there to be a notion of distance + + align:start position:0% +for there to be a notion of distance + + + align:start position:0% +for there to be a notion of distance +between events I haven't + + align:start position:0% + + + + align:start position:0% + +really said what a tensor is carefully + + align:start position:0% +really said what a tensor is carefully + + + align:start position:0% +really said what a tensor is carefully +yet I'm gonna make a more formal + + align:start position:0% +yet I'm gonna make a more formal + + + align:start position:0% +yet I'm gonna make a more formal +definition of this in just a moment but + + align:start position:0% +definition of this in just a moment but + + + align:start position:0% +definition of this in just a moment but +this is your first example of one okay + + align:start position:0% + + + + align:start position:0% + +and so the way in which this actually + + align:start position:0% +and so the way in which this actually + + + align:start position:0% +and so the way in which this actually +gives me a notion of distance it's + + align:start position:0% +gives me a notion of distance it's + + + align:start position:0% +gives me a notion of distance it's +through this that I wrote down right + + align:start position:0% +through this that I wrote down right + + + align:start position:0% +through this that I wrote down right +here okay if I have two events in + + align:start position:0% +here okay if I have two events in + + + align:start position:0% +here okay if I have two events in +space-time that are + + align:start position:0% +space-time that are + + + align:start position:0% +space-time that are +separated by a displacement Delta X the + + align:start position:0% + + + + align:start position:0% + +Delta s squared which + + align:start position:0% + + + + align:start position:0% + +I obtained from this thing is + + align:start position:0% +I obtained from this thing is + + + align:start position:0% +I obtained from this thing is +fundamentally the notion of distance + + align:start position:0% +fundamentally the notion of distance + + + align:start position:0% +fundamentally the notion of distance +between those two events that I use and + + align:start position:0% +between those two events that I use and + + + align:start position:0% +between those two events that I use and +notice it's a little less normal of a + + align:start position:0% +notice it's a little less normal of a + + + align:start position:0% +notice it's a little less normal of a +distance than you're used to when you do + + align:start position:0% +distance than you're used to when you do + + + align:start position:0% +distance than you're used to when you do +sort of ordinary Euclidean geometry this + + align:start position:0% +sort of ordinary Euclidean geometry this + + + align:start position:0% +sort of ordinary Euclidean geometry this +is a distance whose square can be + + align:start position:0% +is a distance whose square can be + + + align:start position:0% +is a distance whose square can be +negative okay okay + + align:start position:0% + + + + align:start position:0% + +what we like to say is that when you're + + align:start position:0% +what we like to say is that when you're + + + align:start position:0% +what we like to say is that when you're +working in special relativity you know + + align:start position:0% +working in special relativity you know + + + align:start position:0% +working in special relativity you know +that these are not it's not necessarily + + align:start position:0% +that these are not it's not necessarily + + + align:start position:0% +that these are not it's not necessarily +positive the distance between two events + + align:start position:0% +positive the distance between two events + + + align:start position:0% +positive the distance between two events +is not necessarily positive distance + + align:start position:0% +is not necessarily positive distance + + + align:start position:0% +is not necessarily positive distance +squared it's not necessarily positive + + align:start position:0% +squared it's not necessarily positive + + + align:start position:0% +squared it's not necessarily positive +definite okay if it's negative though it + + align:start position:0% +definite okay if it's negative though it + + + align:start position:0% +definite okay if it's negative though it +just means you know it sort of dominated + + align:start position:0% +just means you know it sort of dominated + + + align:start position:0% +just means you know it sort of dominated +by the time interval between them okay + + align:start position:0% +by the time interval between them okay + + + align:start position:0% +by the time interval between them okay +if it's positive you know it's dominated + + align:start position:0% +if it's positive you know it's dominated + + + align:start position:0% +if it's positive you know it's dominated +by the space interval between them if + + align:start position:0% +by the space interval between them if + + + align:start position:0% +by the space interval between them if +it's zero well you actually know you + + align:start position:0% +it's zero well you actually know you + + + align:start position:0% +it's zero well you actually know you +it's actually a little bit confusing at + + align:start position:0% +it's actually a little bit confusing at + + + align:start position:0% +it's actually a little bit confusing at +that point they could be in fact you + + align:start position:0% +that point they could be in fact you + + + align:start position:0% +that point they could be in fact you +know very widely separated in both space + + align:start position:0% +know very widely separated in both space + + + align:start position:0% +know very widely separated in both space +and time but in such a way that a light + + align:start position:0% +and time but in such a way that a light + + + align:start position:0% +and time but in such a way that a light +being could connect them okay so there's + + align:start position:0% +being could connect them okay so there's + + + align:start position:0% +being could connect them okay so there's +a lot of information encoded in that now + + align:start position:0% +a lot of information encoded in that now + + + align:start position:0% +a lot of information encoded in that now +as we move forward a second + + align:start position:0% +as we move forward a second + + + align:start position:0% +as we move forward a second +as we move forward we're + + align:start position:0% + + + + align:start position:0% + +gonna upgrade this okay so right now our + + align:start position:0% +gonna upgrade this okay so right now our + + + align:start position:0% +gonna upgrade this okay so right now our +metric is just this simple matrix of + + align:start position:0% +metric is just this simple matrix of + + + align:start position:0% +metric is just this simple matrix of +minus one zeros and ones one + + align:start position:0% +minus one zeros and ones one + + + align:start position:0% +minus one zeros and ones one +of the things that we're going to do is + + align:start position:0% +of the things that we're going to do is + + + align:start position:0% +of the things that we're going to do is +sort of a warm-up exercise so the more + + align:start position:0% +sort of a warm-up exercise so the more + + + align:start position:0% +sort of a warm-up exercise so the more +complicated things we're going to do + + align:start position:0% +complicated things we're going to do + + + align:start position:0% +complicated things we're going to do +later is we're gonna move away from + + align:start position:0% +later is we're gonna move away from + + + align:start position:0% +later is we're gonna move away from +special relativity and Cartesian + + align:start position:0% +special relativity and Cartesian + + + align:start position:0% +special relativity and Cartesian +coordinate it in polar coordinates + + align:start position:0% +coordinate it in polar coordinates + + + align:start position:0% +coordinate it in polar coordinates +that's gonna be kind of like a warm-up + + align:start position:0% +that's gonna be kind of like a warm-up + + + align:start position:0% +that's gonna be kind of like a warm-up +zone and so when we do that this we're + + align:start position:0% +zone and so when we do that this we're + + + align:start position:0% +zone and so when we do that this we're +always going to reserve Etta for the the + + align:start position:0% +always going to reserve Etta for the the + + + align:start position:0% +always going to reserve Etta for the the +metric of special relativity when I'm + + align:start position:0% +metric of special relativity when I'm + + + align:start position:0% +metric of special relativity when I'm +working in Cartesian coordinates okay + + align:start position:0% +working in Cartesian coordinates okay + + + align:start position:0% +working in Cartesian coordinates okay +just it's a great symbol to have for + + align:start position:0% +just it's a great symbol to have for + + + align:start position:0% +just it's a great symbol to have for +that and it's it's a useful thing to + + align:start position:0% +that and it's it's a useful thing to + + + align:start position:0% +that and it's it's a useful thing to +always have that definition in mind I + + align:start position:0% +always have that definition in mind I + + + align:start position:0% +always have that definition in mind I +can + + align:start position:0% +can + + + align:start position:0% +can +continue to do special relativity but + + align:start position:0% +continue to do special relativity but + + + align:start position:0% +continue to do special relativity but +then working in coordinates that are you + + align:start position:0% +then working in coordinates that are you + + + align:start position:0% +then working in coordinates that are you +know spherical like or polar like or + + align:start position:0% +know spherical like or polar like or + + + align:start position:0% +know spherical like or polar like or +something like that then this is gonna + + align:start position:0% +something like that then this is gonna + + + align:start position:0% +something like that then this is gonna +become a function okay and what that is + + align:start position:0% +become a function okay and what that is + + + align:start position:0% +become a function okay and what that is +going to mean is that things like my + + align:start position:0% +going to mean is that things like my + + + align:start position:0% +going to mean is that things like my +little basis vectors are gonna have more + + align:start position:0% +little basis vectors are gonna have more + + + align:start position:0% +little basis vectors are gonna have more +complicated behavior ah later in the + + align:start position:0% +complicated behavior ah later in the + + + align:start position:0% +complicated behavior ah later in the +course we will then show that when + + align:start position:0% +course we will then show that when + + + align:start position:0% +course we will then show that when +gravity enters into the picture + + align:start position:0% +gravity enters into the picture + + + align:start position:0% +gravity enters into the picture +essentially + + align:start position:0% +essentially + + + align:start position:0% +essentially +the essence of gravity is going to be + + align:start position:0% +the essence of gravity is going to be + + + align:start position:0% +the essence of gravity is going to be +encoded in this thing as well in a way + + align:start position:0% +encoded in this thing as well in a way + + + align:start position:0% +encoded in this thing as well in a way +where again it's gonna be a function + + align:start position:0% +where again it's gonna be a function + + + align:start position:0% +where again it's gonna be a function +it's gonna vary as a function of space + + align:start position:0% +it's gonna vary as a function of space + + + align:start position:0% +it's gonna vary as a function of space +and time and the dynamics of gravity + + align:start position:0% +and time and the dynamics of gravity + + + align:start position:0% +and time and the dynamics of gravity +will be buried in that sort of funny + + align:start position:0% +will be buried in that sort of funny + + + align:start position:0% +will be buried in that sort of funny +that it really does just sort of start + + align:start position:0% +that it really does just sort of start + + + align:start position:0% +that it really does just sort of start +out I mean if you take that thing and + + align:start position:0% +out I mean if you take that thing and + + + align:start position:0% +out I mean if you take that thing and +you set delta T equals zero this is just + + align:start position:0% +you set delta T equals zero this is just + + + align:start position:0% +you set delta T equals zero this is just +the bloody Pythagorean theorem okay that + + align:start position:0% +the bloody Pythagorean theorem okay that + + + align:start position:0% +the bloody Pythagorean theorem okay that +is all this is put + + align:start position:0% +is all this is put + + + align:start position:0% +is all this is put +time back in and it's sort of is the + + align:start position:0% +time back in and it's sort of is the + + + align:start position:0% +time back in and it's sort of is the +generalization of Pythagoras to + + align:start position:0% +generalization of Pythagoras to + + + align:start position:0% +generalization of Pythagoras to +space-time and in fact we're going to + + align:start position:0% +space-time and in fact we're going to + + + align:start position:0% +space-time and in fact we're going to +take advantage of that and sort of + + align:start position:0% +take advantage of that and sort of + + + align:start position:0% +take advantage of that and sort of +define a geometry that looks like this + + align:start position:0% +define a geometry that looks like this + + + align:start position:0% +define a geometry that looks like this +as being flat in the same way that a + + align:start position:0% +as being flat in the same way that a + + + align:start position:0% +as being flat in the same way that a +board is flat and the Pythagorean + + align:start position:0% +board is flat and the Pythagorean + + + align:start position:0% +board is flat and the Pythagorean +theorem works perfectly on it then + + align:start position:0% +theorem works perfectly on it then + + + align:start position:0% +theorem works perfectly on it then +we're gonna start thinking about what + + align:start position:0% +we're gonna start thinking about what + + + align:start position:0% +we're gonna start thinking about what +happens when it becomes curved then you + + align:start position:0% +happens when it becomes curved then you + + + align:start position:0% +happens when it becomes curved then you +start thinking about things like what is + + align:start position:0% +start thinking about things like what is + + + align:start position:0% +start thinking about things like what is +the geometry on the surface of a sphere + + align:start position:0% +the geometry on the surface of a sphere + + + align:start position:0% +the geometry on the surface of a sphere +look like okay that's just sort of + + align:start position:0% +look like okay that's just sort of + + + align:start position:0% +look like okay that's just sort of +pointing ahead so I just throw that out + + align:start position:0% +pointing ahead so I just throw that out + + + align:start position:0% +pointing ahead so I just throw that out +you so that you get ready for some of + + align:start position:0% +you so that you get ready for some of + + + align:start position:0% +you so that you get ready for some of +the concepts that we will we'll be + + align:start position:0% +the concepts that we will we'll be + + + align:start position:0% +the concepts that we will we'll be +talking about soon so let me write this + + align:start position:0% +talking about soon so let me write this + + + align:start position:0% +talking about soon so let me write this +actually in terms of differentials sort + + align:start position:0% +actually in terms of differentials sort + + + align:start position:0% +actually in terms of differentials sort +of useful for what I want to say next + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +a little differential if I have two + + align:start position:0% +a little differential if I have two + + + align:start position:0% +a little differential if I have two +events in space-time that are very close + + align:start position:0% +events in space-time that are very close + + + align:start position:0% +events in space-time that are very close +to one another I + + align:start position:0% + + + + align:start position:0% + +can write them like so and what I've + + align:start position:0% +can write them like so and what I've + + + align:start position:0% +can write them like so and what I've +essentially done here is written DX + + align:start position:0% +essentially done here is written DX + + + align:start position:0% +essentially done here is written DX +DX + + align:start position:0% +DX + + + align:start position:0% +DX +alpha e alpha ah before + + align:start position:0% +alpha e alpha ah before + + + align:start position:0% +alpha e alpha ah before +I get into some more sort of a couple of + + align:start position:0% +I get into some more sort of a couple of + + + align:start position:0% +I get into some more sort of a couple of +important physically important for + + align:start position:0% +important physically important for + + + align:start position:0% +important physically important for +vectors reason I did this is I want to + + align:start position:0% +vectors reason I did this is I want to + + + align:start position:0% +vectors reason I did this is I want to +make an important point about some + + align:start position:0% +make an important point about some + + + align:start position:0% +make an important point about some +notation and terminology that is used if + + align:start position:0% +notation and terminology that is used if + + + align:start position:0% +notation and terminology that is used if +it is the case that the displacement + + align:start position:0% +it is the case that the displacement + + + align:start position:0% +it is the case that the displacement +vector is related to the differentials + + align:start position:0% +vector is related to the differentials + + + align:start position:0% +vector is related to the differentials +of your coordinates like so we + + align:start position:0% + + + + align:start position:0% + +say that e alpha + + align:start position:0% +say that e alpha + + + align:start position:0% +say that e alpha +is a coordinate + + align:start position:0% + + + + align:start position:0% + +basis vector + + align:start position:0% +basis vector + + + align:start position:0% +basis vector +what + + align:start position:0% + + + + align:start position:0% + +it does is it + + align:start position:0% +it does is it + + + align:start position:0% +it does is it +transforms a differential of your + + align:start position:0% +transforms a differential of your + + + align:start position:0% +transforms a differential of your +coordinate into a differential of a + + align:start position:0% +coordinate into a differential of a + + + align:start position:0% +coordinate into a differential of a +differential + + align:start position:0% +differential + + + align:start position:0% +differential +vector in space-time now you may be + + align:start position:0% +vector in space-time now you may be + + + align:start position:0% +vector in space-time now you may be +thinking to yourself okay well what + + align:start position:0% +thinking to yourself okay well what + + + align:start position:0% +thinking to yourself okay well what +other kind can their big + + align:start position:0% + + + + align:start position:0% + +well + + align:start position:0% + + + + align:start position:0% + +this is where my little spiel there a + + align:start position:0% +this is where my little spiel there a + + + align:start position:0% +this is where my little spiel there a +second ago about how we're gonna start + + align:start position:0% +second ago about how we're gonna start + + + align:start position:0% +second ago about how we're gonna start +looking at more complicated complicated + + align:start position:0% +looking at more complicated complicated + + + align:start position:0% +looking at more complicated complicated +things it's going to become important so + + align:start position:0% +things it's going to become important so + + + align:start position:0% +things it's going to become important so +when we're working in a Cartesian like + + align:start position:0% +when we're working in a Cartesian like + + + align:start position:0% +when we're working in a Cartesian like +coordinate system the fact that this is + + align:start position:0% +coordinate system the fact that this is + + + align:start position:0% +coordinate system the fact that this is +what we call a coordinate basis vector + + align:start position:0% +what we call a coordinate basis vector + + + align:start position:0% +what we call a coordinate basis vector +isn't very interesting suppose + + align:start position:0% + + + + align:start position:0% + +I was working in some kind of a + + align:start position:0% +I was working in some kind of a + + + align:start position:0% +I was working in some kind of a +curvilinear coordinate system okay + + align:start position:0% +curvilinear coordinate system okay + + + align:start position:0% +curvilinear coordinate system okay +circle coordinates and let's just focus + + align:start position:0% +circle coordinates and let's just focus + + + align:start position:0% +circle coordinates and let's just focus +on three space for a second so + + align:start position:0% + + + + align:start position:0% + +if I have write out a sort of analogous + + align:start position:0% +if I have write out a sort of analogous + + + align:start position:0% +if I have write out a sort of analogous +equation and + + align:start position:0% +equation and + + + align:start position:0% +equation and +curvilinear + + align:start position:0% +curvilinear + + + align:start position:0% +curvilinear +coordinates okay + + align:start position:0% +coordinates okay + + + align:start position:0% +coordinates okay +so here's the three space version of + + align:start position:0% +so here's the three space version of + + + align:start position:0% +so here's the three space version of +that now let's imagine that I equals 1 + + align:start position:0% +that now let's imagine that I equals 1 + + + align:start position:0% +that now let's imagine that I equals 1 +corresponds to radius I equals 2 is + + align:start position:0% +corresponds to radius I equals 2 is + + + align:start position:0% +corresponds to radius I equals 2 is +Theta I equals 3 is Phi then + + align:start position:0% +Theta I equals 3 is Phi then + + + align:start position:0% +Theta I equals 3 is Phi then +this would be dr ER plus d + + align:start position:0% + + + + align:start position:0% + +theta D theta plus + + align:start position:0% +theta D theta plus + + + align:start position:0% +theta D theta plus +D Phi D Phi does + + align:start position:0% + + + + align:start position:0% + +that disturb you at all + + align:start position:0% + + + + align:start position:0% + +this has two dimensions of lengths these + + align:start position:0% +this has two dimensions of lengths these + + + align:start position:0% +this has two dimensions of lengths these +have the dimensions of of angle in + + align:start position:0% +have the dimensions of of angle in + + + align:start position:0% +have the dimensions of of angle in +order for this to work er must be + + align:start position:0% +order for this to work er must be + + + align:start position:0% +order for this to work er must be +dimensionless data must have the + + align:start position:0% +dimensionless data must have the + + + align:start position:0% +dimensionless data must have the +dimensions of length D Phi must have the + + align:start position:0% +dimensions of length D Phi must have the + + + align:start position:0% +dimensions of length D Phi must have the +dimensions of length this is + + align:start position:0% +dimensions of length this is + + + align:start position:0% +dimensions of length this is +the form of a base this is what a + + align:start position:0% +the form of a base this is what a + + + align:start position:0% +the form of a base this is what a +coordinate basis looks like when I am + + align:start position:0% +coordinate basis looks like when I am + + + align:start position:0% +coordinate basis looks like when I am +dealing with well well we're gonna use + + align:start position:0% +dealing with well well we're gonna use + + + align:start position:0% +dealing with well well we're gonna use +this a lot in this thing so this is I + + align:start position:0% +this a lot in this thing so this is I + + + align:start position:0% +this a lot in this thing so this is I +introduce this right now because you are + + align:start position:0% +introduce this right now because you are + + + align:start position:0% +introduce this right now because you are +all probably looking at that and some + + align:start position:0% +all probably looking at that and some + + + align:start position:0% +all probably looking at that and some +small part of you inside is weeping + + align:start position:0% +small part of you inside is weeping + + + align:start position:0% +small part of you inside is weeping +because what you want me to write down + + align:start position:0% +because what you want me to write down + + + align:start position:0% +because what you want me to write down +is this okay + + align:start position:0% + + + + align:start position:0% + +this looks like something you're used to + + align:start position:0% +this looks like something you're used to + + + align:start position:0% +this looks like something you're used to +so + + align:start position:0% + + + + align:start position:0% + +I throw this out here right now just + + align:start position:0% +I throw this out here right now just + + + align:start position:0% +I throw this out here right now just +because I want to make sure you're aware + + align:start position:0% +because I want to make sure you're aware + + + align:start position:0% +because I want to make sure you're aware +that there are some equations and some + + align:start position:0% +that there are some equations and some + + + align:start position:0% +that there are some equations and some +foundational stuff you guys have been + + align:start position:0% +foundational stuff you guys have been + + + align:start position:0% +foundational stuff you guys have been +doing over the years particularly they + + align:start position:0% +doing over the years particularly they + + + align:start position:0% +doing over the years particularly they +shows up a lot when you've done a em out + + align:start position:0% +shows up a lot when you've done a em out + + + align:start position:0% +shows up a lot when you've done a em out +of a textbook like Purcell or Griffiths + + align:start position:0% +of a textbook like Purcell or Griffiths + + + align:start position:0% +of a textbook like Purcell or Griffiths +or Jackson because + + align:start position:0% +or Jackson because + + + align:start position:0% +or Jackson because +there's some derivative operators which + + align:start position:0% +there's some derivative operators which + + + align:start position:0% +there's some derivative operators which +are assuming that your basis factors are + + align:start position:0% +are assuming that your basis factors are + + + align:start position:0% +are assuming that your basis factors are +what we call orthonormal so + + align:start position:0% + + + + align:start position:0% + +my e I hat here it + + align:start position:0% +my e I hat here it + + + align:start position:0% +my e I hat here it +is an orthonormal basis and + + align:start position:0% + + + + align:start position:0% + +orthonormal basis is defined such that + + align:start position:0% +orthonormal basis is defined such that + + + align:start position:0% +orthonormal basis is defined such that +the + + align:start position:0% + + + + align:start position:0% + +dot product of any two members of this + + align:start position:0% +dot product of any two members of this + + + align:start position:0% +dot product of any two members of this +thing + + align:start position:0% + + + + align:start position:0% + +gives me back the Kronecker Delta okay + + align:start position:0% +gives me back the Kronecker Delta okay + + + align:start position:0% +gives me back the Kronecker Delta okay +that is not necessarily the case when I + + align:start position:0% +that is not necessarily the case when I + + + align:start position:0% +that is not necessarily the case when I +work with a coordinate basis our + + align:start position:0% + + + + align:start position:0% + +basis has er + + align:start position:0% +basis has er + + + align:start position:0% +basis has er +er + + align:start position:0% +er + + + align:start position:0% +er +equals one yeah nice but when I do Ethan + + align:start position:0% +equals one yeah nice but when I do Ethan + + + align:start position:0% +equals one yeah nice but when I do Ethan +is ADA I get + + align:start position:0% + + + + align:start position:0% + +R squared he + + align:start position:0% + + + + align:start position:0% + +535 will be R squared sine squared theta + + align:start position:0% +535 will be R squared sine squared theta + + + align:start position:0% +535 will be R squared sine squared theta +and + + align:start position:0% +and + + + align:start position:0% +and +what I'm gonna do when I start + + align:start position:0% +what I'm gonna do when I start + + + align:start position:0% +what I'm gonna do when I start +generalizing these things I'm gonna + + align:start position:0% +generalizing these things I'm gonna + + + align:start position:0% +generalizing these things I'm gonna +change my you know this this thing which + + align:start position:0% +change my you know this this thing which + + + align:start position:0% +change my you know this this thing which +I defined up here yeah + + align:start position:0% +I defined up here yeah + + + align:start position:0% +I defined up here yeah +yeah right here so when I said ADA alpha + + align:start position:0% +yeah right here so when I said ADA alpha + + + align:start position:0% +yeah right here so when I said ADA alpha +beta is e alpha D beta and I made it + + align:start position:0% +beta is e alpha D beta and I made it + + + align:start position:0% +beta is e alpha D beta and I made it +this thing I'm gonna generalize this and + + align:start position:0% +this thing I'm gonna generalize this and + + + align:start position:0% +this thing I'm gonna generalize this and +say at the dot product of any two basis + + align:start position:0% +say at the dot product of any two basis + + + align:start position:0% +say at the dot product of any two basis +vectors it gives me a more general + + align:start position:0% +vectors it gives me a more general + + + align:start position:0% +vectors it gives me a more general +notion of a metric tensor and the values + + align:start position:0% +notion of a metric tensor and the values + + + align:start position:0% +notion of a metric tensor and the values +in the metric tensor may be functions + + align:start position:0% +in the metric tensor may be functions + + + align:start position:0% +in the metric tensor may be functions +like this okay right + + align:start position:0% +like this okay right + + + align:start position:0% +like this okay right +now throw that out there you know this + + align:start position:0% +now throw that out there you know this + + + align:start position:0% +now throw that out there you know this +might be sort of like just like a peak + + align:start position:0% +might be sort of like just like a peak + + + align:start position:0% +might be sort of like just like a peak +of the horrors that lie ahead okay we're + + align:start position:0% +of the horrors that lie ahead okay we're + + + align:start position:0% +of the horrors that lie ahead okay we're +not gonna worry about this too much just + + align:start position:0% +not gonna worry about this too much just + + + align:start position:0% +not gonna worry about this too much just +yet but I want you to be prepared for + + align:start position:0% +yet but I want you to be prepared for + + + align:start position:0% +yet but I want you to be prepared for +this in particular it's really useful to + + align:start position:0% +this in particular it's really useful to + + + align:start position:0% +this in particular it's really useful to +have this notion of a coordinate basis + + align:start position:0% +have this notion of a coordinate basis + + + align:start position:0% +have this notion of a coordinate basis +versus an orthonormal basis in your head + + align:start position:0% +versus an orthonormal basis in your head + + + align:start position:0% +versus an orthonormal basis in your head +okay we're going to start defining some + + align:start position:0% +okay we're going to start defining some + + + align:start position:0% +okay we're going to start defining some +derivative operations soon in fact + + align:start position:0% +derivative operations soon in fact + + + align:start position:0% +derivative operations soon in fact +probably won't get to them today but + + align:start position:0% +probably won't get to them today but + + + align:start position:0% +probably won't get to them today but +they will be present when we start doing + + align:start position:0% +they will be present when we start doing + + + align:start position:0% +they will be present when we start doing +a lecture 3 and there's a couple results + + align:start position:0% +a lecture 3 and there's a couple results + + + align:start position:0% +a lecture 3 and there's a couple results +that come up where everyone's sort of + + align:start position:0% +that come up where everyone's sort of + + + align:start position:0% +that come up where everyone's sort of +like wait I knew that the divergence had + + align:start position:0% +like wait I knew that the divergence had + + + align:start position:0% +like wait I knew that the divergence had +a factor of R on that derivative there + + align:start position:0% +a factor of R on that derivative there + + + align:start position:0% +a factor of R on that derivative there +where'd it go okay it's because we're + + align:start position:0% +where'd it go okay it's because we're + + + align:start position:0% +where'd it go okay it's because we're +not working in an orthonormal basis all + + align:start position:0% +not working in an orthonormal basis all + + + align:start position:0% +not working in an orthonormal basis all +right I'm + + align:start position:0% +right I'm + + + align:start position:0% +right I'm +a little sick of math so let's do a + + align:start position:0% +a little sick of math so let's do a + + + align:start position:0% +a little sick of math so let's do a +little fist + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +so far the actual only physical + + align:start position:0% +so far the actual only physical + + + align:start position:0% +so far the actual only physical +four-vector + + align:start position:0% +four-vector + + + align:start position:0% +four-vector +that I've introduced is a displacement + + align:start position:0% +that I've introduced is a displacement + + + align:start position:0% +that I've introduced is a displacement +factor from + + align:start position:0% + + + + align:start position:0% + +the displacement factor it's really easy + + align:start position:0% +the displacement factor it's really easy + + + align:start position:0% +the displacement factor it's really easy +to make and apply the first and simplest + + align:start position:0% +to make and apply the first and simplest + + + align:start position:0% +to make and apply the first and simplest +important for brach four-vector which + + align:start position:0% + + + + align:start position:0% + +is known as the floor velocity this + + align:start position:0% + + + + align:start position:0% + +tells me the rate of displacement of an + + align:start position:0% +tells me the rate of displacement of an + + + align:start position:0% +tells me the rate of displacement of an +observer as this person moves through + + align:start position:0% +observer as this person moves through + + + align:start position:0% +observer as this person moves through +space time per + + align:start position:0% +space time per + + + align:start position:0% +space time per +unit and we're going to be careful about + + align:start position:0% +unit and we're going to be careful about + + + align:start position:0% +unit and we're going to be careful about +this in this class D + + align:start position:0% +this in this class D + + + align:start position:0% +this in this class D +tau is the time interval + + align:start position:0% +tau is the time interval + + + align:start position:0% +tau is the time interval +as + + align:start position:0% +as + + + align:start position:0% +as +measured + + align:start position:0% +measured + + + align:start position:0% +measured +along + + align:start position:0% + + + + align:start position:0% + +the trajectory of the + + align:start position:0% + + + + align:start position:0% + +observer with four velocity U in + + align:start position:0% +observer with four velocity U in + + + align:start position:0% +observer with four velocity U in +other words it's a very long-winded way + + align:start position:0% +other words it's a very long-winded way + + + align:start position:0% +other words it's a very long-winded way +of saying it it's an interval of proper + + align:start position:0% +of saying it it's an interval of proper + + + align:start position:0% +of saying it it's an interval of proper +time in + + align:start position:0% + + + + align:start position:0% + +English the word property and it sounds + + align:start position:0% +English the word property and it sounds + + + align:start position:0% +English the word property and it sounds +very like whoo I don't want to use + + align:start position:0% +very like whoo I don't want to use + + + align:start position:0% +very like whoo I don't want to use +improper time I better use that but this + + align:start position:0% +improper time I better use that but this + + + align:start position:0% +improper time I better use that but this +actually I think it comes from French it + + align:start position:0% +actually I think it comes from French it + + + align:start position:0% +actually I think it comes from French it +just refers to the fact that it's one's + + align:start position:0% +just refers to the fact that it's one's + + + align:start position:0% +just refers to the fact that it's one's +own time + + align:start position:0% +own time + + + align:start position:0% +own time +apparently in German people say eigen + + align:start position:0% +apparently in German people say eigen + + + align:start position:0% +apparently in German people say eigen +site so you know there's a couple of + + align:start position:0% +site so you know there's a couple of + + + align:start position:0% +site so you know there's a couple of +different words for a minute so but + + align:start position:0% +different words for a minute so but + + + align:start position:0% +different words for a minute so but +proper time is what we use in + + align:start position:0% +proper time is what we use in + + + align:start position:0% +proper time is what we use in +special relativity if we see someone + + align:start position:0% +special relativity if we see someone + + + align:start position:0% +special relativity if we see someone +going by with constant velocity a + + align:start position:0% +going by with constant velocity a + + + align:start position:0% +going by with constant velocity a +particular + + align:start position:0% +particular + + + align:start position:0% +particular +observer who sees you know we're here in + + align:start position:0% +observer who sees you know we're here in + + + align:start position:0% +observer who sees you know we're here in +the room someone comes through therefore + + align:start position:0% +the room someone comes through therefore + + + align:start position:0% +the room someone comes through therefore +velocity is U we would see therefore + + align:start position:0% +velocity is U we would see therefore + + + align:start position:0% +velocity is U we would see therefore +velocity to have the components gamma + + align:start position:0% +velocity to have the components gamma + + + align:start position:0% +velocity to have the components gamma +gamma V okay where gamma I'll remind you + + align:start position:0% +gamma V okay where gamma I'll remind you + + + align:start position:0% +gamma V okay where gamma I'll remind you +is the special relativistic Lorentz + + align:start position:0% +is the special relativistic Lorentz + + + align:start position:0% +is the special relativistic Lorentz +factor and + + align:start position:0% +factor and + + + align:start position:0% +factor and +I'll remind you again we've set speed of + + align:start position:0% +I'll remind you again we've set speed of + + + align:start position:0% +I'll remind you again we've set speed of +light to one a very + + align:start position:0% +light to one a very + + + align:start position:0% +light to one a very +useful thing which we're actually going + + align:start position:0% +useful thing which we're actually going + + + align:start position:0% +useful thing which we're actually going +to take advantage of quite a bit is that + + align:start position:0% +to take advantage of quite a bit is that + + + align:start position:0% +to take advantage of quite a bit is that +in the rest frame of you + + align:start position:0% +in the rest frame of you + + + align:start position:0% +in the rest frame of you +in + + align:start position:0% + + + + align:start position:0% + +the rest frame of you or + + align:start position:0% + + + + align:start position:0% + +I should say the observer who's for + + align:start position:0% +I should say the observer who's for + + + align:start position:0% +I should say the observer who's for +velocity is you okay + + align:start position:0% + + + + align:start position:0% + +just have one in a time like direction + + align:start position:0% +just have one in a time like direction + + + align:start position:0% +just have one in a time like direction +see if you want to put your factors back + + align:start position:0% +see if you want to put your factors back + + + align:start position:0% +see if you want to put your factors back +into there and that's basically saying + + align:start position:0% +into there and that's basically saying + + + align:start position:0% +into there and that's basically saying +that the person is standing still but + + align:start position:0% +that the person is standing still but + + + align:start position:0% +that the person is standing still but +moving through time okay because + + align:start position:0% +moving through time okay because + + + align:start position:0% +moving through time okay because +you are always moving through time all + + align:start position:0% +you are always moving through time all + + + align:start position:0% +you are always moving through time all +right ah from the floor velocity for + + align:start position:0% + + + + align:start position:0% + +an observer who has a foreign object I + + align:start position:0% +an observer who has a foreign object I + + + align:start position:0% +an observer who has a foreign object I +should say who has some mass we can + + align:start position:0% +should say who has some mass we can + + + align:start position:0% +should say who has some mass we can +easily define the for momentum + + align:start position:0% + + + + align:start position:0% + +where this em is known as the rest mass + + align:start position:0% +where this em is known as the rest mass + + + align:start position:0% +where this em is known as the rest mass +of this object worth + + align:start position:0% + + + + align:start position:0% + +a bit of description here you will often + + align:start position:0% +a bit of description here you will often + + + align:start position:0% +a bit of description here you will often +see particularly in some older textbooks + + align:start position:0% +see particularly in some older textbooks + + + align:start position:0% +see particularly in some older textbooks +that discuss special relativity people + + align:start position:0% +that discuss special relativity people + + + align:start position:0% +that discuss special relativity people +like to talk about the relativistic mass + + align:start position:0% +like to talk about the relativistic mass + + + align:start position:0% +like to talk about the relativistic mass +okay and that comes from the fact that + + align:start position:0% +okay and that comes from the fact that + + + align:start position:0% +okay and that comes from the fact that +if I write out what this thing looks + + align:start position:0% +if I write out what this thing looks + + + align:start position:0% +if I write out what this thing looks +like according to some particular + + align:start position:0% +like according to some particular + + + align:start position:0% +like according to some particular +observer you + + align:start position:0% + + + + align:start position:0% + +have this gamma M entering into both of + + align:start position:0% +have this gamma M entering into both of + + + align:start position:0% +have this gamma M entering into both of +the complex and so older textbooks often + + align:start position:0% +the complex and so older textbooks often + + + align:start position:0% +the complex and so older textbooks often +call gamma M the relativistic mass + + align:start position:0% +call gamma M the relativistic mass + + + align:start position:0% +call gamma M the relativistic mass +that's not really the way people have + + align:start position:0% +that's not really the way people have + + + align:start position:0% +that's not really the way people have +over the course of the past couple + + align:start position:0% +over the course of the past couple + + + align:start position:0% +over the course of the past couple +decades they've moved away from that and + + align:start position:0% +decades they've moved away from that and + + + align:start position:0% +decades they've moved away from that and +it's just more useful to focus on the + + align:start position:0% +it's just more useful to focus on the + + + align:start position:0% +it's just more useful to focus on the +rest mass is the only really meaningful + + align:start position:0% +rest mass is the only really meaningful + + + align:start position:0% +rest mass is the only really meaningful +mass because as we'll see in a moment + + align:start position:0% +mass because as we'll see in a moment + + + align:start position:0% +mass because as we'll see in a moment +it's a Lorentz invariant okay we'll see + + align:start position:0% +it's a Lorentz invariant okay we'll see + + + align:start position:0% +it's a Lorentz invariant okay we'll see +wow that is in literally about three + + align:start position:0% +wow that is in literally about three + + + align:start position:0% +wow that is in literally about three +minutes and so what we're instead going + + align:start position:0% +minutes and so what we're instead going + + + align:start position:0% +minutes and so what we're instead going +to say is that as seen by some + + align:start position:0% +to say is that as seen by some + + + align:start position:0% +to say is that as seen by some +particular observer this + + align:start position:0% +particular observer this + + + align:start position:0% +particular observer this +has a time light component that is the + + align:start position:0% +has a time light component that is the + + + align:start position:0% +has a time light component that is the +energy that that observer would measure + + align:start position:0% +energy that that observer would measure + + + align:start position:0% +energy that that observer would measure +and a space set of space like compliance + + align:start position:0% +and a space set of space like compliance + + + align:start position:0% +and a space set of space like compliance +that are the momentum that that observer + + align:start position:0% +that are the momentum that that observer + + + align:start position:0% +that are the momentum that that observer +will measure so + + align:start position:0% + + + + align:start position:0% + +where we get a bit of important physics + + align:start position:0% +where we get a bit of important physics + + + align:start position:0% +where we get a bit of important physics +out of all this stuff is by coupling + + align:start position:0% +out of all this stuff is by coupling + + + align:start position:0% +out of all this stuff is by coupling +these two four vectors to the scalar + + align:start position:0% +these two four vectors to the scalar + + + align:start position:0% +these two four vectors to the scalar +product that we made up + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +the first one if you do you dot you + + align:start position:0% +the first one if you do you dot you + + + align:start position:0% +the first one if you do you dot you +queen to any observer that's it's going + + align:start position:0% +queen to any observer that's it's going + + + align:start position:0% +queen to any observer that's it's going +to be minus gamma squared plus + + align:start position:0% +to be minus gamma squared plus + + + align:start position:0% +to be minus gamma squared plus +gamma squared V squared and + + align:start position:0% + + + + align:start position:0% + +with + + align:start position:0% +with + + + align:start position:0% +with +about twenty seconds worth of analysis + + align:start position:0% +about twenty seconds worth of analysis + + + align:start position:0% +about twenty seconds worth of analysis +you can find that this is always equal + + align:start position:0% +you can find that this is always equal + + + align:start position:0% +you can find that this is always equal +to minus + + align:start position:0% +to minus + + + align:start position:0% +to minus +one actually + + align:start position:0% + + + + align:start position:0% + +there's an even trickier way to do this + + align:start position:0% +there's an even trickier way to do this + + + align:start position:0% +there's an even trickier way to do this +suppose + + align:start position:0% +suppose + + + align:start position:0% +suppose +I evaluate this in the rest frame of the + + align:start position:0% +I evaluate this in the rest frame of the + + + align:start position:0% +I evaluate this in the rest frame of the +observer who's for velocity is U well in + + align:start position:0% +observer who's for velocity is U well in + + + align:start position:0% +observer who's for velocity is U well in +the rest frame V is 0 and gamma is one + + align:start position:0% +the rest frame V is 0 and gamma is one + + + align:start position:0% +the rest frame V is 0 and gamma is one +and I get minus one and this is an + + align:start position:0% +and I get minus one and this is an + + + align:start position:0% +and I get minus one and this is an +invariant so whatever I get in that + + align:start position:0% +invariant so whatever I get in that + + + align:start position:0% +invariant so whatever I get in that +particular frame must be obtained in all + + align:start position:0% +particular frame must be obtained in all + + + align:start position:0% +particular frame must be obtained in all +frames that's a trick we're gonna use + + align:start position:0% +frames that's a trick we're gonna use + + + align:start position:0% +frames that's a trick we're gonna use +over and over and over again sometimes + + align:start position:0% +over and over and over again sometimes + + + align:start position:0% +over and over and over again sometimes +you can identify you know you get some + + align:start position:0% +you can identify you know you get some + + + align:start position:0% +you can identify you know you get some +kind of god-awful expression that just + + align:start position:0% +kind of god-awful expression that just + + + align:start position:0% +kind of god-awful expression that just +makes you want to vomit but then you go + + align:start position:0% +makes you want to vomit but then you go + + + align:start position:0% +makes you want to vomit but then you go +wait a minute what would this look like + + align:start position:0% +wait a minute what would this look like + + + align:start position:0% +wait a minute what would this look like +in frame blah blah blah you sort of + + align:start position:0% +in frame blah blah blah you sort of + + + align:start position:0% +in frame blah blah blah you sort of +think about some particular frame and in + + align:start position:0% +think about some particular frame and in + + + align:start position:0% +think about some particular frame and in +that frame it may simplify and if it + + align:start position:0% +that frame it may simplify and if it + + + align:start position:0% +that frame it may simplify and if it +does and it's a frame invariant quantity + + align:start position:0% +does and it's a frame invariant quantity + + + align:start position:0% +does and it's a frame invariant quantity +Mazel Tov you have just basically won + + align:start position:0% +Mazel Tov you have just basically won + + + align:start position:0% +Mazel Tov you have just basically won +the lottery you've got this all taken + + align:start position:0% +the lottery you've got this all taken + + + align:start position:0% +the lottery you've got this all taken +care of go on with your life so the + + align:start position:0% + + + + align:start position:0% + +for velocity has a scalar prior to + + align:start position:0% +for velocity has a scalar prior to + + + align:start position:0% +for velocity has a scalar prior to +itself that is always minus one okay how + + align:start position:0% + + + + align:start position:0% + +about the for momentum well the for + + align:start position:0% +about the for momentum well the for + + + align:start position:0% +about the for momentum well the for +momentum is just for velocity x max + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +that's just minus M squared but we also + + align:start position:0% +that's just minus M squared but we also + + + align:start position:0% +that's just minus M squared but we also +know it's related to these two other + + align:start position:0% +know it's related to these two other + + + align:start position:0% +know it's related to these two other +quantities which are important in + + align:start position:0% +quantities which are important in + + + align:start position:0% +quantities which are important in +physics this is related to the energy + + align:start position:0% +physics this is related to the energy + + + align:start position:0% +physics this is related to the energy +into the momentum so this is also equal + + align:start position:0% +into the momentum so this is also equal + + + align:start position:0% +into the momentum so this is also equal +to minus e squared plus so + + align:start position:0% + + + + align:start position:0% + +this is the ordinary three the + + align:start position:0% +this is the ordinary three the + + + align:start position:0% +this is the ordinary three the +magnitude of the three vector part of + + align:start position:0% +magnitude of the three vector part of + + + align:start position:0% +magnitude of the three vector part of +this thing as measured by the observer + + align:start position:0% +this thing as measured by the observer + + + align:start position:0% +this thing as measured by the observer +who who breaks up the floor momentum in + + align:start position:0% +who who breaks up the floor momentum in + + + align:start position:0% +who who breaks up the floor momentum in +this way so what this means is I can + + align:start position:0% +this way so what this means is I can + + + align:start position:0% +this way so what this means is I can +manipulate this guy around a little bit + + align:start position:0% +manipulate this guy around a little bit + + + align:start position:0% +manipulate this guy around a little bit +here anybody + + align:start position:0% + + + + align:start position:0% + +who works in particle physics is + + align:start position:0% +who works in particle physics is + + + align:start position:0% +who works in particle physics is +presumably familiar with this equation + + align:start position:0% +presumably familiar with this equation + + + align:start position:0% +presumably familiar with this equation +sometimes it appears with the piece + + align:start position:0% +sometimes it appears with the piece + + + align:start position:0% +sometimes it appears with the piece +where it moved on to the other side if + + align:start position:0% +where it moved on to the other side if + + + align:start position:0% +where it moved on to the other side if +it looks a little bit unfamiliar to you + + align:start position:0% +it looks a little bit unfamiliar to you + + + align:start position:0% +it looks a little bit unfamiliar to you +let me put some factors of C back in + + align:start position:0% +let me put some factors of C back in + + + align:start position:0% +let me put some factors of C back in +this so + + align:start position:0% +this so + + + align:start position:0% +this so +remember we have set C equal to one when + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +you put it back in that's + + align:start position:0% +you put it back in that's + + + align:start position:0% +you put it back in that's +what this is so it drops out of this in + + align:start position:0% +what this is so it drops out of this in + + + align:start position:0% +what this is so it drops out of this in +a very very simple way one + + align:start position:0% + + + + align:start position:0% + +of the uses of this and many + + align:start position:0% +of the uses of this and many + + + align:start position:0% +of the uses of this and many +of you have done exercises presumably in + + align:start position:0% +of you have done exercises presumably in + + + align:start position:0% +of you have done exercises presumably in +some previous study that does this and + + align:start position:0% +some previous study that does this and + + + align:start position:0% +some previous study that does this and +ob8 one + + align:start position:0% +ob8 one + + + align:start position:0% +ob8 one +exercise on the pset that was just + + align:start position:0% +exercise on the pset that was just + + + align:start position:0% +exercise on the pset that was just +posted where you exploit this so + + align:start position:0% + + + + align:start position:0% + +a key bit of physics the reason why we + + align:start position:0% +a key bit of physics the reason why we + + + align:start position:0% +a key bit of physics the reason why we +care about for momentum is it's in one + + align:start position:0% +care about for momentum is it's in one + + + align:start position:0% +care about for momentum is it's in one +mathematical object allows us to combine + + align:start position:0% +mathematical object allows us to combine + + + align:start position:0% +mathematical object allows us to combine +conservation of energy and conservation + + align:start position:0% +conservation of energy and conservation + + + align:start position:0% +conservation of energy and conservation +of momentum + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +conservation of 4-momentum puts + + align:start position:0% +conservation of 4-momentum puts + + + align:start position:0% +conservation of 4-momentum puts +both conservation of energy and + + align:start position:0% +both conservation of energy and + + + align:start position:0% +both conservation of energy and +conservation of momentum into one + + align:start position:0% +conservation of momentum into one + + + align:start position:0% +conservation of momentum into one +mathematical object so if I have n + + align:start position:0% +mathematical object so if I have n + + + align:start position:0% +mathematical object so if I have n +particles that interact then + + align:start position:0% + + + + align:start position:0% + +the + + align:start position:0% + + + + align:start position:0% + +total for momentum is + + align:start position:0% + + + + align:start position:0% + +conserved in the interaction okay + + align:start position:0% + + + + align:start position:0% + +so yeah + + align:start position:0% +so yeah + + + align:start position:0% +so yeah +we talked a little bit more about this + + align:start position:0% +we talked a little bit more about this + + + align:start position:0% +we talked a little bit more about this +and then just sort of quickly move on so + + align:start position:0% +and then just sort of quickly move on so + + + align:start position:0% +and then just sort of quickly move on so +we + + align:start position:0% +we + + + align:start position:0% +we +combining this with the fact that we are + + align:start position:0% +combining this with the fact that we are + + + align:start position:0% +combining this with the fact that we are +free to change our reference frames + + align:start position:0% +free to change our reference frames + + + align:start position:0% +free to change our reference frames +often it gives us a trick that allows us + + align:start position:0% +often it gives us a trick that allows us + + + align:start position:0% +often it gives us a trick that allows us +to really simplify a lot of analysis so + + align:start position:0% +to really simplify a lot of analysis so + + + align:start position:0% +to really simplify a lot of analysis so +if + + align:start position:0% + + + + align:start position:0% + +I have n particles that are sort of + + align:start position:0% +I have n particles that are sort of + + + align:start position:0% +I have n particles that are sort of +swarming around and doing some horrible + + align:start position:0% +swarming around and doing some horrible + + + align:start position:0% +swarming around and doing some horrible +horrible bit of business but + + align:start position:0% +horrible bit of business but + + + align:start position:0% +horrible bit of business but +I need to study and I need to have a + + align:start position:0% +I need to study and I need to have a + + + align:start position:0% +I need to study and I need to have a +good understanding of we + + align:start position:0% + + + + align:start position:0% + +can often vastly simplify our algebra by + + align:start position:0% + + + + align:start position:0% + +choosing a special and very convenient + + align:start position:0% +choosing a special and very convenient + + + align:start position:0% +choosing a special and very convenient +frame of reference in which to do our + + align:start position:0% +frame of reference in which to do our + + + align:start position:0% +frame of reference in which to do our +analysis choose + + align:start position:0% + + + + align:start position:0% + +the center of momentum frame + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +this is the frame in which that + + align:start position:0% +this is the frame in which that + + + align:start position:0% +this is the frame in which that +pea tote socio + + align:start position:0% + + + + align:start position:0% + +em center of momentum has + + align:start position:0% + + + + align:start position:0% + +zero spatial momentum okay in that frame + + align:start position:0% +zero spatial momentum okay in that frame + + + align:start position:0% +zero spatial momentum okay in that frame +you have just as much momentum going to + + align:start position:0% +you have just as much momentum going to + + + align:start position:0% +you have just as much momentum going to +the left as going to the right just as + + align:start position:0% +the left as going to the right just as + + + align:start position:0% +the left as going to the right just as +much going forward is going backwards as + + align:start position:0% +much going forward is going backwards as + + + align:start position:0% +much going forward is going backwards as +much going up is going down and so this + + align:start position:0% +much going up is going down and so this + + + align:start position:0% +much going up is going down and so this +tends out to be so it the classic + + align:start position:0% +tends out to be so it the classic + + + align:start position:0% +tends out to be so it the classic +example of where this is really useful + + align:start position:0% +example of where this is really useful + + + align:start position:0% +example of where this is really useful +is + + align:start position:0% +is + + + align:start position:0% +is +when + + align:start position:0% +when + + + align:start position:0% +when +you are studying particle + + align:start position:0% +you are studying particle + + + align:start position:0% +you are studying particle +collisions and you're looking at things + + align:start position:0% +collisions and you're looking at things + + + align:start position:0% +collisions and you're looking at things +like the production of new particles so + + align:start position:0% + + + + align:start position:0% + +imagine you've got particle + + align:start position:0% +imagine you've got particle + + + align:start position:0% +imagine you've got particle +a with some four momentum PA coming in + + align:start position:0% +a with some four momentum PA coming in + + + align:start position:0% +a with some four momentum PA coming in +like this particle B's got some four + + align:start position:0% +like this particle B's got some four + + + align:start position:0% +like this particle B's got some four +momentum coming in like this these + + align:start position:0% +momentum coming in like this these + + + align:start position:0% +momentum coming in like this these +guys collide and they do so I work in + + align:start position:0% +guys collide and they do so I work in + + + align:start position:0% +guys collide and they do so I work in +the center of momentum frame I might + + align:start position:0% +the center of momentum frame I might + + + align:start position:0% +the center of momentum frame I might +want to just calculate the energy at + + align:start position:0% +want to just calculate the energy at + + + align:start position:0% +want to just calculate the energy at +which they just happen to produce some + + align:start position:0% +which they just happen to produce some + + + align:start position:0% +which they just happen to produce some +new pair + + align:start position:0% +new pair + + + align:start position:0% +new pair +of particles at rest that we like to + + align:start position:0% +of particles at rest that we like to + + + align:start position:0% +of particles at rest that we like to +find the threshold for this particular + + align:start position:0% +find the threshold for this particular + + + align:start position:0% +find the threshold for this particular +creation process okay so you're they're + + align:start position:0% +creation process okay so you're they're + + + align:start position:0% +creation process okay so you're they're +gonna play with one problem on the piece + + align:start position:0% +gonna play with one problem on the piece + + + align:start position:0% +gonna play with one problem on the piece +that it's kind of like that let's + + align:start position:0% +that it's kind of like that let's + + + align:start position:0% +that it's kind of like that let's +see I think I will do + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +all the dot products that I have been + + align:start position:0% +all the dot products that I have been + + + align:start position:0% +all the dot products that I have been +talking about so far have + + align:start position:0% + + + + align:start position:0% + +been a dot product of a four vector with + + align:start position:0% +been a dot product of a four vector with + + + align:start position:0% +been a dot product of a four vector with +itself okay I did you dot into you I did + + align:start position:0% +itself okay I did you dot into you I did + + + align:start position:0% +itself okay I did you dot into you I did +P dotted into P I invented a frame in + + align:start position:0% +P dotted into P I invented a frame in + + + align:start position:0% +P dotted into P I invented a frame in +which P has a particularly simple form + + align:start position:0% +which P has a particularly simple form + + + align:start position:0% +which P has a particularly simple form +and then when you actually do some the + + align:start position:0% +and then when you actually do some the + + + align:start position:0% +and then when you actually do some the +analysis you would probably take that P + + align:start position:0% +analysis you would probably take that P + + + align:start position:0% +analysis you would probably take that P +tote and dot it into itself I haven't + + align:start position:0% +tote and dot it into itself I haven't + + + align:start position:0% +tote and dot it into itself I haven't +done anything that looks at you know the + + align:start position:0% +done anything that looks at you know the + + + align:start position:0% +done anything that looks at you know the +crossing between these two things okay + + align:start position:0% +crossing between these two things okay + + + align:start position:0% +crossing between these two things okay +dotting one into the other need + + align:start position:0% + + + + align:start position:0% + +to go through a very useful result that + + align:start position:0% +to go through a very useful result that + + + align:start position:0% +to go through a very useful result that +follows by combining P with you they're + + align:start position:0% +follows by combining P with you they're + + + align:start position:0% +follows by combining P with you they're +very specific notion of P in a very + + align:start position:0% +very specific notion of P in a very + + + align:start position:0% +very specific notion of P in a very +specific notion of you so + + align:start position:0% + + + + align:start position:0% + +let's let key be + + align:start position:0% +let's let key be + + + align:start position:0% +let's let key be +the full row mentum of a particle I'll + + align:start position:0% +the full row mentum of a particle I'll + + + align:start position:0% +the full row mentum of a particle I'll +call it egg let's + + align:start position:0% + + + + align:start position:0% + +let you be + + align:start position:0% + + + + align:start position:0% + +the four velocity not + + align:start position:0% +the four velocity not + + + align:start position:0% +the four velocity not +of a but the four velocity of + + align:start position:0% + + + + align:start position:0% + +observer oh ok + + align:start position:0% +observer oh ok + + + align:start position:0% +observer oh ok +[Applause] + + align:start position:0% + + + + align:start position:0% + +so particle a might be a muon that was + + align:start position:0% +so particle a might be a muon that was + + + align:start position:0% +so particle a might be a muon that was +creating upper atmosphere and it's + + align:start position:0% +creating upper atmosphere and it's + + + align:start position:0% +creating upper atmosphere and it's +crashing through our room right now + + align:start position:0% +crashing through our room right now + + + align:start position:0% +crashing through our room right now +observer Oh might be you're hyperactive + + align:start position:0% +observer Oh might be you're hyperactive + + + align:start position:0% +observer Oh might be you're hyperactive +friend who is jogging through the room + + align:start position:0% +friend who is jogging through the room + + + align:start position:0% +friend who is jogging through the room +and half the speed of light question + + align:start position:0% +and half the speed of light question + + + align:start position:0% +and half the speed of light question +I want to ask is what does + + align:start position:0% +I want to ask is what does + + + align:start position:0% +I want to ask is what does +Oh measure as the energy of + + align:start position:0% + + + + align:start position:0% + +particle a + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +the naive way to do this which I will + + align:start position:0% +the naive way to do this which I will + + + align:start position:0% +the naive way to do this which I will +emphasize is not wrong okay what you + + align:start position:0% +emphasize is not wrong okay what you + + + align:start position:0% +emphasize is not wrong okay what you +might do is sort of go okay well we're + + align:start position:0% +might do is sort of go okay well we're + + + align:start position:0% +might do is sort of go okay well we're +sitting here this room is our laboratory + + align:start position:0% +sitting here this room is our laboratory + + + align:start position:0% +sitting here this room is our laboratory +I've measured this thing in my lab so I + + align:start position:0% +I've measured this thing in my lab so I + + + align:start position:0% +I've measured this thing in my lab so I +know P as I measure it I can see oh ja + + align:start position:0% +know P as I measure it I can see oh ja + + + align:start position:0% +know P as I measure it I can see oh ja +ghing by so I know O's for velocity as I + + align:start position:0% +ghing by so I know O's for velocity as I + + + align:start position:0% +ghing by so I know O's for velocity as I +measure it so what I should do is figure + + align:start position:0% +measure it so what I should do is figure + + + align:start position:0% +measure it so what I should do is figure +out the Lorentz transformation that + + align:start position:0% +out the Lorentz transformation that + + + align:start position:0% +out the Lorentz transformation that +takes me into the rest frame of oh once + + align:start position:0% +takes me into the rest frame of oh once + + + align:start position:0% +takes me into the rest frame of oh once +I have that Lorentz transformation I'll + + align:start position:0% +I have that Lorentz transformation I'll + + + align:start position:0% +I have that Lorentz transformation I'll +do I'll apply that Lorentz + + align:start position:0% +do I'll apply that Lorentz + + + align:start position:0% +do I'll apply that Lorentz +transformation to the four vector ki + + align:start position:0% +transformation to the four vector ki + + + align:start position:0% +transformation to the four vector ki +boom that will give me that energy okay + + align:start position:0% +boom that will give me that energy okay + + + align:start position:0% +boom that will give me that energy okay +that will work that will absolutely work + + align:start position:0% +that will work that will absolutely work + + + align:start position:0% +that will work that will absolutely work +but + + align:start position:0% + + + + align:start position:0% + +there's an easier way to do it so + + align:start position:0% + + + + align:start position:0% + +one thing you should note is that + + align:start position:0% +one thing you should note is that + + + align:start position:0% +one thing you should note is that +everybody + + align:start position:0% +everybody + + + align:start position:0% +everybody +represents + + align:start position:0% + + + + align:start position:0% + +that for velocity as + + align:start position:0% +that for velocity as + + + align:start position:0% +that for velocity as +in + + align:start position:0% +in + + + align:start position:0% +in +energy there + + align:start position:0% +energy there + + + align:start position:0% +energy there +was at the four momentum as an energy + + align:start position:0% +was at the four momentum as an energy + + + align:start position:0% +was at the four momentum as an energy +and a three momentum in particular + + align:start position:0% +and a three momentum in particular + + + align:start position:0% +and a three momentum in particular +though they represent it as the energy + + align:start position:0% +though they represent it as the energy + + + align:start position:0% +though they represent it as the energy +that they would measure and the four + + align:start position:0% +that they would measure and the four + + + align:start position:0% +that they would measure and the four +moment to me the three momentum that + + align:start position:0% +moment to me the three momentum that + + + align:start position:0% +moment to me the three momentum that +they would measure so that means P + + align:start position:0% +they would measure so that means P + + + align:start position:0% +they would measure so that means P +as seen + + align:start position:0% +as seen + + + align:start position:0% +as seen +by Oh is e according to oh and P + + align:start position:0% +by Oh is e according to oh and P + + + align:start position:0% +by Oh is e according to oh and P +according to + + align:start position:0% + + + + align:start position:0% + +that + + align:start position:0% +that + + + align:start position:0% +that +eeeh cornea Oh is what we want and I + + align:start position:0% +eeeh cornea Oh is what we want and I + + + align:start position:0% +eeeh cornea Oh is what we want and I +just told you a moment ago you know if + + align:start position:0% +just told you a moment ago you know if + + + align:start position:0% +just told you a moment ago you know if +you have peeing your own reference frame + + align:start position:0% +you have peeing your own reference frame + + + align:start position:0% +you have peeing your own reference frame +and you have you and your own reference + + align:start position:0% +and you have you and your own reference + + + align:start position:0% +and you have you and your own reference +frame you can do this whole math let's + + align:start position:0% +frame you can do this whole math let's + + + align:start position:0% +frame you can do this whole math let's +Lorentz transformations and get it out + + align:start position:0% +Lorentz transformations and get it out + + + align:start position:0% +Lorentz transformations and get it out +but you also know that in + + align:start position:0% + + + + align:start position:0% + +Ozone reference frame o represents + + align:start position:0% + + + + align:start position:0% + +therefore velocity as one + + align:start position:0% +therefore velocity as one + + + align:start position:0% +therefore velocity as one +in + + align:start position:0% +in + + + align:start position:0% +in +the time light Direction zero in the + + align:start position:0% +the time light Direction zero in the + + + align:start position:0% +the time light Direction zero in the +spatial direction so + + align:start position:0% + + + + align:start position:0% + +what this means is if I go into o's + + align:start position:0% +what this means is if I go into o's + + + align:start position:0% +what this means is if I go into o's +reference frame if I go into their + + align:start position:0% +reference frame if I go into their + + + align:start position:0% +reference frame if I go into their +inertial reference frame notice + + align:start position:0% + + + + align:start position:0% + +that if I take the dot product of P and + + align:start position:0% +that if I take the dot product of P and + + + align:start position:0% +that if I take the dot product of P and +you I get e times 1 and P times 0 so + + align:start position:0% + + + + align:start position:0% + +that is just negative it's exactly no + + align:start position:0% +that is just negative it's exactly no + + + align:start position:0% +that is just negative it's exactly no +it's exactly what I want module a minus + + align:start position:0% +it's exactly what I want module a minus + + + align:start position:0% +it's exactly what I want module a minus +sign and so you go okay well I'll flip + + align:start position:0% +sign and so you go okay well I'll flip + + + align:start position:0% +sign and so you go okay well I'll flip +my minus sign around + + align:start position:0% + + + + align:start position:0% + +and you think okay great but that's new + + align:start position:0% +and you think okay great but that's new + + + align:start position:0% +and you think okay great but that's new +I did that using those Quan DS that's + + align:start position:0% +I did that using those Quan DS that's + + + align:start position:0% +I did that using those Quan DS that's +written down the O's reference frame and + + align:start position:0% +written down the O's reference frame and + + + align:start position:0% +written down the O's reference frame and +then you go holy crap that's an + + align:start position:0% +then you go holy crap that's an + + + align:start position:0% +then you go holy crap that's an +invariant scalar product I'm done mic + + align:start position:0% +invariant scalar product I'm done mic + + + align:start position:0% +invariant scalar product I'm done mic +drop leave the room what this means is + + align:start position:0% +drop leave the room what this means is + + + align:start position:0% +drop leave the room what this means is +you start with P as you measure it you + + align:start position:0% +you start with P as you measure it you + + + align:start position:0% +you start with P as you measure it you +as you measure it take the scalar + + align:start position:0% +as you measure it take the scalar + + + align:start position:0% +as you measure it take the scalar +product between the two of them boom the + + align:start position:0% +product between the two of them boom the + + + align:start position:0% +product between the two of them boom the +answer you want pops out no nonsense of + + align:start position:0% +answer you want pops out no nonsense of + + + align:start position:0% +answer you want pops out no nonsense of +Lorentz transformations none of that + + align:start position:0% +Lorentz transformations none of that + + + align:start position:0% +Lorentz transformations none of that +garbage needs to happen you just take + + align:start position:0% +garbage needs to happen you just take + + + align:start position:0% +garbage needs to happen you just take +the inner product and you've got it + + align:start position:0% + + + + align:start position:0% + +that sort of says in words you know no + + align:start position:0% +that sort of says in words you know no + + + align:start position:0% +that sort of says in words you know no +matter what representation you choose to + + align:start position:0% +matter what representation you choose to + + + align:start position:0% +matter what representation you choose to +write down P and un take the dot product + + align:start position:0% +write down P and un take the dot product + + + align:start position:0% +write down P and un take the dot product +Rena two of them throw in a minus sign + + align:start position:0% +Rena two of them throw in a minus sign + + + align:start position:0% +Rena two of them throw in a minus sign +you've got the energy of the particle + + align:start position:0% +you've got the energy of the particle + + + align:start position:0% +you've got the energy of the particle +with P as measured by the observer with + + align:start position:0% +with P as measured by the observer with + + + align:start position:0% +with P as measured by the observer with +you it's + + align:start position:0% + + + + align:start position:0% + +sort of late in the hour the + + align:start position:0% +sort of late in the hour the + + + align:start position:0% +sort of late in the hour the +hour and a half I should say so let me + + align:start position:0% +hour and a half I should say so let me + + + align:start position:0% +hour and a half I should say so let me +just sort of emphasize there are + + align:start position:0% +just sort of emphasize there are + + + align:start position:0% +just sort of emphasize there are +occasional moments in this class where + + align:start position:0% +occasional moments in this class where + + + align:start position:0% +occasional moments in this class where +if you're dozing off a little bit I + + align:start position:0% +if you're dozing off a little bit I + + + align:start position:0% +if you're dozing off a little bit I +suggest you pop up and tattoo this into + + align:start position:0% +suggest you pop up and tattoo this into + + + align:start position:0% +suggest you pop up and tattoo this into +a neuron somewhere this is one of those + + align:start position:0% +a neuron somewhere this is one of those + + + align:start position:0% +a neuron somewhere this is one of those +moments okay this is web result that + + align:start position:0% +moments okay this is web result that + + + align:start position:0% +moments okay this is web result that +we're going to use over and over and + + align:start position:0% +we're going to use over and over and + + + align:start position:0% +we're going to use over and over and +over again because this holds isn't just + + align:start position:0% +over again because this holds isn't just + + + align:start position:0% +over again because this holds isn't just +a special relativity okay we are + + align:start position:0% +a special relativity okay we are + + + align:start position:0% +a special relativity okay we are +actually when we start talking about + + align:start position:0% +actually when we start talking about + + + align:start position:0% +actually when we start talking about +behavior + + align:start position:0% +behavior + + + align:start position:0% +behavior +of things near black holes there's only + + align:start position:0% +of things near black holes there's only + + + align:start position:0% +of things near black holes there's only +a place where I basically at that point + + align:start position:0% +a place where I basically at that point + + + align:start position:0% +a place where I basically at that point +to say well I'm just gonna use the fact + + align:start position:0% +to say well I'm just gonna use the fact + + + align:start position:0% +to say well I'm just gonna use the fact +that the observer measures an energy + + align:start position:0% +that the observer measures an energy + + + align:start position:0% +that the observer measures an energy +that is given by and I'm gonna write + + align:start position:0% +that is given by and I'm gonna write + + + align:start position:0% +that is given by and I'm gonna write +down that okay the dot product that + + align:start position:0% +down that okay the dot product that + + + align:start position:0% +down that okay the dot product that +involves a little bit more complicated + + align:start position:0% +involves a little bit more complicated + + + align:start position:0% +involves a little bit more complicated +because my metric is hairier but it's + + align:start position:0% +because my metric is hairier but it's + + + align:start position:0% +because my metric is hairier but it's +the exact same physical concept okay let + + align:start position:0% +the exact same physical concept okay let + + + align:start position:0% +the exact same physical concept okay let +me just do one more and then I'm gonna + + align:start position:0% +me just do one more and then I'm gonna + + + align:start position:0% +me just do one more and then I'm gonna +talk without getting into the math about + + align:start position:0% +talk without getting into the math about + + + align:start position:0% +talk without getting into the math about +what I will start with on Tuesday last + + align:start position:0% +what I will start with on Tuesday last + + + align:start position:0% +what I will start with on Tuesday last +for velocity which I was probably useful + + align:start position:0% +for velocity which I was probably useful + + + align:start position:0% +for velocity which I was probably useful +for us to quickly talk about is + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +we've been doing we + + align:start position:0% +we've been doing we + + + align:start position:0% +we've been doing we +talked a lot about for velocity that + + align:start position:0% +talked a lot about for velocity that + + + align:start position:0% +talked a lot about for velocity that +is just one piece we're not talking + + align:start position:0% +is just one piece we're not talking + + + align:start position:0% +is just one piece we're not talking +about sort of the kinematics of bodies + + align:start position:0% +about sort of the kinematics of bodies + + + align:start position:0% +about sort of the kinematics of bodies +moving in space-time you need more + + align:start position:0% +moving in space-time you need more + + + align:start position:0% +moving in space-time you need more +information than its velocity sometimes + + align:start position:0% +information than its velocity sometimes + + + align:start position:0% +information than its velocity sometimes +things are moving around there's + + align:start position:0% +things are moving around there's + + + align:start position:0% +things are moving around there's +additional additional + + align:start position:0% +additional additional + + + align:start position:0% +additional additional +forces acting on them and so we also + + align:start position:0% +forces acting on them and so we also + + + align:start position:0% +forces acting on them and so we also +care about the for acceleration + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% + + + + align:start position:0% + +this is what I get when I take the + + align:start position:0% +this is what I get when I take the + + + align:start position:0% +this is what I get when I take the +derivative with respect to proper time + + align:start position:0% +derivative with respect to proper time + + + align:start position:0% +derivative with respect to proper time +of the four-velocity okay so will there + + align:start position:0% +of the four-velocity okay so will there + + + align:start position:0% +of the four-velocity okay so will there +be some homework exercises that use this + + align:start position:0% +be some homework exercises that use this + + + align:start position:0% +be some homework exercises that use this +the main thing which I want to emphasize + + align:start position:0% +the main thing which I want to emphasize + + + align:start position:0% +the main thing which I want to emphasize +to sort of conclude our calculations for + + align:start position:0% +to sort of conclude our calculations for + + + align:start position:0% +to sort of conclude our calculations for +today is that when I talk about a four + + align:start position:0% +today is that when I talk about a four + + + align:start position:0% +today is that when I talk about a four +velocity of acceleration this has an + + align:start position:0% +velocity of acceleration this has an + + + align:start position:0% +velocity of acceleration this has an +extremely important property it is + + align:start position:0% +extremely important property it is + + + align:start position:0% +extremely important property it is +always the case that + + align:start position:0% + + + + align:start position:0% + +a dotted + + align:start position:0% +a dotted + + + align:start position:0% +a dotted +into u equals + + align:start position:0% +into u equals + + + align:start position:0% +into u equals +zero if + + align:start position:0% + + + + align:start position:0% + +you're used to sort of three-dimensional + + align:start position:0% +you're used to sort of three-dimensional + + + align:start position:0% +you're used to sort of three-dimensional +intuition that may seem weird okay any + + align:start position:0% +intuition that may seem weird okay any + + + align:start position:0% +intuition that may seem weird okay any +time you see a car accelerate from a + + align:start position:0% +time you see a car accelerate from a + + + align:start position:0% +time you see a car accelerate from a +stopped education + + align:start position:0% +stopped education + + + align:start position:0% +stopped education +which is acceleration is clearly not + + align:start position:0% +which is acceleration is clearly not + + + align:start position:0% +which is acceleration is clearly not +orthogonal to its velocity okay but the + + align:start position:0% +orthogonal to its velocity okay but the + + + align:start position:0% +orthogonal to its velocity okay but the +issue here is this is not a spatial dot + + align:start position:0% +issue here is this is not a spatial dot + + + align:start position:0% +issue here is this is not a spatial dot +product this is a space-time dot product + + align:start position:0% +product this is a space-time dot product + + + align:start position:0% +product this is a space-time dot product +and so your intuition has to go out the + + align:start position:0% +and so your intuition has to go out the + + + align:start position:0% +and so your intuition has to go out the +window because of that it's very simple + + align:start position:0% +window because of that it's very simple + + + align:start position:0% +window because of that it's very simple +to prove this remember u dot u equals + + align:start position:0% +to prove this remember u dot u equals + + + align:start position:0% +to prove this remember u dot u equals +minus one so D of U dot u D tau which is + + align:start position:0% +minus one so D of U dot u D tau which is + + + align:start position:0% +minus one so D of U dot u D tau which is +just two u + + align:start position:0% +just two u + + + align:start position:0% +just two u +dot a is the + + align:start position:0% +dot a is the + + + align:start position:0% +dot a is the +derivative of minus one which + + align:start position:0% +derivative of minus one which + + + align:start position:0% +derivative of minus one which +is zero okay + + align:start position:0% +is zero okay + + + align:start position:0% +is zero okay +so this is something that we will + + align:start position:0% +so this is something that we will + + + align:start position:0% +so this is something that we will +exploit if you want to describe the + + align:start position:0% +exploit if you want to describe the + + + align:start position:0% +exploit if you want to describe the +relativistic kinematics of an + + align:start position:0% +relativistic kinematics of an + + + align:start position:0% +relativistic kinematics of an +accelerating body this + + align:start position:0% +accelerating body this + + + align:start position:0% +accelerating body this +is a great thing that we can use to + + align:start position:0% +is a great thing that we can use to + + + align:start position:0% +is a great thing that we can use to +exploit you'll often need a little bit + + align:start position:0% +exploit you'll often need a little bit + + + align:start position:0% +exploit you'll often need a little bit +more information okay we have to give + + align:start position:0% +more information okay we have to give + + + align:start position:0% +more information okay we have to give +you as a bit of additional information + + align:start position:0% +you as a bit of additional information + + + align:start position:0% +you as a bit of additional information +some knowledge about what the + + align:start position:0% +some knowledge about what the + + + align:start position:0% +some knowledge about what the +orientation the acceleration is and + + align:start position:0% +orientation the acceleration is and + + + align:start position:0% +orientation the acceleration is and +things like that okay so there are + + align:start position:0% +things like that okay so there are + + + align:start position:0% +things like that okay so there are +whenever you are given getting just a + + align:start position:0% +whenever you are given getting just a + + + align:start position:0% +whenever you are given getting just a +second ever you're given any kind of + + align:start position:0% +second ever you're given any kind of + + + align:start position:0% +second ever you're given any kind of +differential quantity like this it's not + + align:start position:0% +differential quantity like this it's not + + + align:start position:0% +differential quantity like this it's not +enough to know it's like the + + align:start position:0% +enough to know it's like the + + + align:start position:0% +enough to know it's like the +acceleration of loss you have to also + + align:start position:0% +acceleration of loss you have to also + + + align:start position:0% +acceleration of loss you have to also +have boundary conditions okay and that + + align:start position:0% +have boundary conditions okay and that + + + align:start position:0% +have boundary conditions okay and that +sort of tells you like what the initial + + align:start position:0% +sort of tells you like what the initial + + + align:start position:0% +sort of tells you like what the initial +direction is question + + align:start position:0% +direction is question + + + align:start position:0% +direction is question +that + + align:start position:0% +that + + + align:start position:0% +that +time is the proper time yes that's + + align:start position:0% +time is the proper time yes that's + + + align:start position:0% +time is the proper time yes that's +right so you can still define a proper + + align:start position:0% +right so you can still define a proper + + + align:start position:0% +right so you can still define a proper +time for an accelerating observer it + + align:start position:0% +time for an accelerating observer it + + + align:start position:0% +time for an accelerating observer it +will not relate hold + + align:start position:0% +will not relate hold + + + align:start position:0% +will not relate hold +that thought you're gonna play with this + + align:start position:0% +that thought you're gonna play with this + + + align:start position:0% +that thought you're gonna play with this +a little bit more on a future problem + + align:start position:0% +a little bit more on a future problem + + + align:start position:0% +a little bit more on a future problem +set I mean that the key thing is that + + align:start position:0% +set I mean that the key thing is that + + + align:start position:0% +set I mean that the key thing is that +the way if you have an accelerated + + align:start position:0% +the way if you have an accelerated + + + align:start position:0% +the way if you have an accelerated +observer an interval of proper time as + + align:start position:0% +observer an interval of proper time as + + + align:start position:0% +observer an interval of proper time as +compared to an interval of time for you + + align:start position:0% +compared to an interval of time for you + + + align:start position:0% +compared to an interval of time for you +know someone in a restroom that sees + + align:start position:0% +know someone in a restroom that sees + + + align:start position:0% +know someone in a restroom that sees +this person accelerate away the + + align:start position:0% +this person accelerate away the + + + align:start position:0% +this person accelerate away the +the the conversion between the intervals + + align:start position:0% +the the conversion between the intervals + + + align:start position:0% +the the conversion between the intervals +of time the to measure it evolves okay + + align:start position:0% +of time the to measure it evolves okay + + + align:start position:0% +of time the to measure it evolves okay +so + + align:start position:0% +so + + + align:start position:0% +so +you know let's say you're in this room + + align:start position:0% +you know let's say you're in this room + + + align:start position:0% +you know let's say you're in this room +with me in fact it turns out that if you + + align:start position:0% +with me in fact it turns out that if you + + + align:start position:0% +with me in fact it turns out that if you +accelerate at 1 J for a year you get to + + align:start position:0% +accelerate at 1 J for a year you get to + + + align:start position:0% +accelerate at 1 J for a year you get to +very close to the speed of light okay so + + align:start position:0% +very close to the speed of light okay so + + + align:start position:0% +very close to the speed of light okay so +let's say that you were in a rocket ship + + align:start position:0% +let's say that you were in a rocket ship + + + align:start position:0% +let's say that you were in a rocket ship +right now that launched at with an + + align:start position:0% +right now that launched at with an + + + align:start position:0% +right now that launched at with an +acceleration of G initially you and I + + align:start position:0% +acceleration of G initially you and I + + + align:start position:0% +acceleration of G initially you and I +synchronize + + align:start position:0% +synchronize + + + align:start position:0% +synchronize +our watches and so an interval of a + + align:start position:0% +our watches and so an interval of a + + + align:start position:0% +our watches and so an interval of a +second to me is the same as a second to + + align:start position:0% +second to me is the same as a second to + + + align:start position:0% +second to me is the same as a second to +you half a year later you're moving at + + align:start position:0% +you half a year later you're moving at + + + align:start position:0% +you half a year later you're moving at +something like half the speed of light + + align:start position:0% +something like half the speed of light + + + align:start position:0% +something like half the speed of light +and I will see a noticeable time delay + + align:start position:0% +and I will see a noticeable time delay + + + align:start position:0% +and I will see a noticeable time delay +your interval of an integral of a second + + align:start position:0% +your interval of an integral of a second + + + align:start position:0% +your interval of an integral of a second +as you measure it looks long compared to + + align:start position:0% +as you measure it looks long compared to + + + align:start position:0% +as you measure it looks long compared to +me oh you're six months later you're + + align:start position:0% +me oh you're six months later you're + + + align:start position:0% +me oh you're six months later you're +actually quite close to the speed of + + align:start position:0% +actually quite close to the speed of + + + align:start position:0% +actually quite close to the speed of +light and it gets dilated even more okay + + align:start position:0% +light and it gets dilated even more okay + + + align:start position:0% +light and it gets dilated even more okay +so + + align:start position:0% +so + + + align:start position:0% +so +last thing which I'm going to say and + + align:start position:0% +last thing which I'm going to say and + + + align:start position:0% +last thing which I'm going to say and +I'm not gonna get into too much detail + + align:start position:0% +I'm not gonna get into too much detail + + + align:start position:0% +I'm not gonna get into too much detail +with this yet is we're gonna begin next + + align:start position:0% +with this yet is we're gonna begin next + + + align:start position:0% +with this yet is we're gonna begin next +time by making + + align:start position:0% + + + + align:start position:0% + +a little bit more formal some of the + + align:start position:0% +a little bit more formal some of the + + + align:start position:0% +a little bit more formal some of the +notions that go around so if we just + + align:start position:0% +notions that go around so if we just + + + align:start position:0% +notions that go around so if we just +talked about we've introduced some + + align:start position:0% +talked about we've introduced some + + + align:start position:0% +talked about we've introduced some +physics and some vectors I've given you + + align:start position:0% +physics and some vectors I've given you + + + align:start position:0% +physics and some vectors I've given you +guys one tensor so far the + + align:start position:0% + + + + align:start position:0% + +metric tensor + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +I'm gonna give you in fact I will write + + align:start position:0% +I'm gonna give you in fact I will write + + + align:start position:0% +I'm gonna give you in fact I will write +down a very precise definition of this + + align:start position:0% +down a very precise definition of this + + + align:start position:0% +down a very precise definition of this +right now and we'll pick it up from + + align:start position:0% +right now and we'll pick it up from + + + align:start position:0% +right now and we'll pick it up from +there on Tuesday basic ideas so you guys + + align:start position:0% +there on Tuesday basic ideas so you guys + + + align:start position:0% +there on Tuesday basic ideas so you guys +have seen the 1/10 you've seen so far is + + align:start position:0% +have seen the 1/10 you've seen so far is + + + align:start position:0% +have seen the 1/10 you've seen so far is +the metric tensor and what the metric is + + align:start position:0% +the metric tensor and what the metric is + + + align:start position:0% +the metric tensor and what the metric is +is it sort of a mathematical object that + + align:start position:0% +is it sort of a mathematical object that + + + align:start position:0% +is it sort of a mathematical object that +I put in a pair of four vectors and it + + align:start position:0% +I put in a pair of four vectors and it + + + align:start position:0% +I put in a pair of four vectors and it +spits out a quantity that is a Lorentz + + align:start position:0% +spits out a quantity that is a Lorentz + + + align:start position:0% +spits out a quantity that is a Lorentz +invariant scalar okay that characterizes + + align:start position:0% +invariant scalar okay that characterizes + + + align:start position:0% +invariant scalar okay that characterizes +what we call the inner product of those + + align:start position:0% +what we call the inner product of those + + + align:start position:0% +what we call the inner product of those +two four vectors more + + align:start position:0% +two four vectors more + + + align:start position:0% +two four vectors more +generally I'm going to define a tensor + + align:start position:0% +generally I'm going to define a tensor + + + align:start position:0% +generally I'm going to define a tensor +of + + align:start position:0% + + + + align:start position:0% + +type zero n as + + align:start position:0% +type zero n as + + + align:start position:0% +type zero n as +a function + + align:start position:0% +a function + + + align:start position:0% +a function +or mapping of + + align:start position:0% + + + + align:start position:0% + +n for + + align:start position:0% +n for + + + align:start position:0% +n for +vectors into + + align:start position:0% + + + + align:start position:0% + +Lorentz + + align:start position:0% +Lorentz + + + align:start position:0% +Lorentz +invariant scalars which + + align:start position:0% + + + + align:start position:0% + +is linear in each + + align:start position:0% +is linear in each + + + align:start position:0% +is linear in each +of its and arguments so + + align:start position:0% + + + + align:start position:0% + +I will pick it up here on Tuesday is + + align:start position:0% +I will pick it up here on Tuesday is + + + align:start position:0% +I will pick it up here on Tuesday is +only just say in words the metric is a + + align:start position:0% +only just say in words the metric is a + + + align:start position:0% +only just say in words the metric is a +zero two tensor I put in two four + + align:start position:0% +zero two tensor I put in two four + + + align:start position:0% +zero two tensor I put in two four +vectors it spits out a Lorentz invariant + + align:start position:0% +vectors it spits out a Lorentz invariant + + + align:start position:0% +vectors it spits out a Lorentz invariant +scalar we're going to before too long I + + align:start position:0% +scalar we're going to before too long I + + + align:start position:0% +scalar we're going to before too long I +come up with a couple of things that + + align:start position:0% +come up with a couple of things that + + + align:start position:0% +come up with a couple of things that +involve three real vectors see me three + + align:start position:0% +involve three real vectors see me three + + + align:start position:0% +involve three real vectors see me three +four vectors too many numbers they're a + + align:start position:0% +four vectors too many numbers they're a + + + align:start position:0% +four vectors too many numbers they're a +trio of four vectors which it then maps + + align:start position:0% +trio of four vectors which it then maps + + + align:start position:0% +trio of four vectors which it then maps +to a Lorentz invariant scale some of + + align:start position:0% +to a Lorentz invariant scale some of + + + align:start position:0% +to a Lorentz invariant scale some of +them will take in four four vectors and + + align:start position:0% +them will take in four four vectors and + + + align:start position:0% +them will take in four four vectors and +produce a Lorentz invariant scalar + + align:start position:0% +produce a Lorentz invariant scalar + + + align:start position:0% +produce a Lorentz invariant scalar +notice I wrote this in a sort of funny + + align:start position:0% +notice I wrote this in a sort of funny + + + align:start position:0% +notice I wrote this in a sort of funny +way the zero end sort of begs were there + + align:start position:0% +way the zero end sort of begs were there + + + align:start position:0% +way the zero end sort of begs were there +to be sort of a n zero okay to do that I + + align:start position:0% +to be sort of a n zero okay to do that I + + + align:start position:0% +to be sort of a n zero okay to do that I +have to introduce a dual an object that + + align:start position:0% +have to introduce a dual an object that + + + align:start position:0% +have to introduce a dual an object that +is sort of dual to a vector okay we're + + align:start position:0% +is sort of dual to a vector okay we're + + + align:start position:0% +is sort of dual to a vector okay we're +going to talk about that those are + + align:start position:0% +going to talk about that those are + + + align:start position:0% +going to talk about that those are +objects called one forms which actually + + align:start position:0% +objects called one forms which actually + + + align:start position:0% +objects called one forms which actually +happened to be a species of vector we're + + align:start position:0% +happened to be a species of vector we're + + + align:start position:0% +happened to be a species of vector we're +actually going to then learn that the + + align:start position:0% +actually going to then learn that the + + + align:start position:0% +actually going to then learn that the +vector is itself a tensor and so we will + + align:start position:0% +vector is itself a tensor and so we will + + + align:start position:0% +vector is itself a tensor and so we will +make a very general classification of + + align:start position:0% +make a very general classification of + + + align:start position:0% +make a very general classification of +these things and we'll see that vectors + + align:start position:0% +these things and we'll see that vectors + + + align:start position:0% +these things and we'll see that vectors +are just a subset of these tensors and + + align:start position:0% +are just a subset of these tensors and + + + align:start position:0% +are just a subset of these tensors and +at last we'll sort of have all the + + align:start position:0% +at last we'll sort of have all the + + + align:start position:0% +at last we'll sort of have all the +mathematics in place we can sort of lose + + align:start position:0% +mathematics in place we can sort of lose + + + align:start position:0% +mathematics in place we can sort of lose +some of these distinctions and just life + + align:start position:0% +some of these distinctions and just life + + + align:start position:0% +some of these distinctions and just life +goes on and we can start actually doing + + align:start position:0% +goes on and we can start actually doing + + + align:start position:0% +goes on and we can start actually doing +some physics with these all right I will + + align:start position:0% +some physics with these all right I will + + + align:start position:0% +some physics with these all right I will +pick it up there on Tuesday \ No newline at end of file diff --git a/Ttezuzs39nk.txt b/Ttezuzs39nk.txt new file mode 100644 index 0000000000000000000000000000000000000000..707b045207b1639883dc4fd22074c7919f600f36 --- /dev/null +++ b/Ttezuzs39nk.txt @@ -0,0 +1,3274 @@ +Good morning, +everyone. + +Glad you are all here bright +and early. + +I'm counting the days till the +TA's outnumber the students. + +They'll show up. +We return to a familiar story. + +This is part two, +the Empire Strikes Back. + +So last time, +our adversary, + +the graph, came to us with a +problem. + +We have a source, +and we had a directed graph, + +and we had weights on the +edges, and they were all + +nonnegative. +And there was happiness. + +And we triumphed over the +Empire by designing Dijkstra's + +algorithm, and very efficiently +finding single source shortest + +paths, shortest path weight from +s to every other vertex. + +Today, however, +the Death Star has a new trick + +up its sleeve, +and we have negative weights, + +potentially. +And we're going to have to + +somehow deal with, +in particular, + +negative weight cycles. +And we saw that when we have a + +negative weight cycle, +we can just keep going around, + +and around, and around, +and go back in time farther, + +and farther, +and farther. + +And we can get to be +arbitrarily far back in the + +past. +And so there's no shortest + +path, because whatever path you +take you can get a shorter one. + +So we want to address that +issue today, and we're going to + +come up with a new algorithm +actually simpler than Dijkstra, + +but not as fast, +called the Bellman-Ford + +algorithm. +And, it's going to allow + +negative weights, +and in some sense allow + +negative weight cycles, +although maybe not as much as + +you might hope. +We have to leave room for a + +sequel, of course. +OK, so the Bellman-Ford + +algorithm, invented by two guys, +as you might expect, + +it computes the shortest path +weights. + +So, it makes no assumption +about the weights. + +Weights are arbitrary, +and it's going to compute the + +shortest path weights. +So, remember this notation: + +delta of s, v is the weight of +the shortest path from s to v. + +s was called a source vertex. +And, we want to compute these + +weights for all vertices, +little v. + +The claim is that computing +from s to everywhere is no + +harder than computing s to a +particular location. + +So, we're going to do for all +them. + +It's still going to be the case +here. + +And, it allows negative +weights. + +And this is the good case, +but there's an alternative, + +which is that Bellman-Ford may +just say, oops, + +there's a negative weight +cycle. + +And in that case it will just +say so. + +So, they say a negative weight +cycle exists. + +Therefore, some of these deltas +are minus infinity. + +And that seems weird. +So, Bellman-Ford as we'll + +present it today is intended for +the case, but there are no + +negative weights cycles, +which is more intuitive. + +It sort of allows them, +but it will just report them. + +In that case, +it will not give you delta + +values. +You can change the algorithm to + +give you delta values in that +case, but we are not going to + +see it here. +So, in exercise, + +after you see the algorithm, +exercise is: + +compute these deltas in all +cases. + +So, it's not hard to do. +But we don't have time for it + +here. +So, here's the algorithm. + +It's pretty straightforward. +As I said, it's easier than + +Dijkstra. +It's a relaxation algorithm. + +So the main thing that it does +is relax edges just like + +Dijkstra. +So, we'll be able to use a lot + +of dilemmas from Dijkstra. +And proof of correctness will + +be three times shorter because +the first two thirds we already + +have from Dijkstra. +But I'm jumping ahead a bit. + +So, the first part is +initialization. + +Again, d of v will represent +the estimated distance from s to + +v. +And we're going to be updating + +those estimates as the algorithm +goes along. + +And initially, +d of s is zero, + +which now may not be the right +answer conceivably. + +Everyone else is infinity, +which is certainly an upper + +bound. +OK, these are both upper bounds + +on the true distance. +So that's fine. + +That's initialization just like +before. + +And now we have a main loop +which happens v minus one times. + +We're not actually going to use +the index i. + +It's just a counter. + +And we're just going to look at +every edge and relax it. + +It's a very simple idea. +If you learn about relaxation, + +this is the first thing you +might try. + +The question is when do you +stop. + +It's sort of like I have this +friend to what he was like six + +years old he would claim, +oh, I know how to spell banana. + +I just don't know when to stop. +OK, same thing with relaxation. + +This is our relaxation step +just as before. + +We look at the edge; +we see whether it violates the + +triangle inequality according to +our current estimates we know + +the distance from s to v should +be at most distance from s to + +plus the weight of that edge +from u to v. + +If it isn't, +we set it equal. + +We've proved that this is +always an OK thing to do. + +We never violate, +I mean, these d of v's never + +get too small if we do a bunch +of relaxations. + +So, the idea is you take every +edge. + +You relax it. +I don't care which order. + +Just relax every edge, +one each. + +And that do that V minus one +times. + +The claim is that that should +be enough if you have no + +negative weights cycles. +So, if there's a negative + +weight cycle, +we need to figure it out. + +And, we'll do that in a fairly +straightforward way, + +which is we're going to do +exactly the same thing. + +So this is outside before loop +here. + +We'll have the same four loops +for each edge in our graph. + +We'll try to relax it. +And if you can relax it, + +the claim is that there has to +be a negative weight cycle. + +So this is the main thing that +needs proof. + +OK, and that's the algorithm. +So the claim is that at the + +ends we should have d of v, +let's see, L's so to speak. + +d of v equals delta of s comma +v for every vertex, + +v. +If we don't find a negative + +weight cycle according to this +rule, that we should have all + +the shortest path weights. +That's the claim. + +Now, the first question is, +in here, the running time is + +very easy to analyze. +So let's start with the running + +time. +We can compare it to Dijkstra, + +which is over here. +What is the running time of + +this algorithm? +V times E, exactly. + +OK, I'm going to assume, +because it's pretty reasonable, + +that V and E are both positive. +Then it's V times E. + +So, this is a little bit +slower, or a fair amount slower, + +than Dijkstra's algorithm. +There it is: + +E plus V log V is essentially, +ignoring the logs is pretty + +much linear time. +Here we have something that's + +at least quadratic in V, +assuming your graph is + +connected. +So, it's slower, + +but it's going to handle these +negative weights. + +Dijkstra can't handle negative +weights at all. + +So, let's do an example, +make it clear why you might + +hope this algorithm works. +And then we'll prove that it + +works, of course. +But the proof will be pretty + +easy. +So, I'm going to draw a graph + +that has negative weights, +but no negative weight cycles + +so that I get an interesting +answer. + +Good. +The other thing I need in order + +to make the output of this +algorithm well defined, + +it depends in which order you +visit the edges. + +So I'm going to assign an +arbitrary order to these edges. + +I could just ask you for an +order, but to be consistent with + +the notes, I'll put an ordering +on it. + +Let's say I put number four, +say that's the fourth edge I'll + +visit. +It doesn't matter. + +But it will affect what happens +during the algorithm for a + +particular graph. + +Do they get them all? +One, two, three, + +four, five, six, +seven, eight, + +OK. +And my source is going to be A. + +And, that's it. +So, I want to run this + +algorithm. +I'm just going to initialize + +everything. +So, I set the estimates for s + +to be zero, and everyone else to +be infinity. + +And to give me some notion of +time, over here I'm going to + +draw or write down what all of +these d values are as the + +algorithm proceeds because I'm +going to start crossing them out + +and rewriting them that the +figure will get a little bit + +messier. +But we can keep track of it + +over here. +It's initially zero and + +infinities. +Yeah? + +It doesn't matter. +So, for the algorithm you can + +go to the edges in a different +order every time if you want. + +We'll prove that, +but here I'm going to go + +through the same order every +time. + +Good question. +It turns out it doesn't matter + +here. +OK, so here's the starting + +point. +Now I'm going to relax every + +edge. +So, there's going to be a lot + +of edges here that don't do +anything. + +I try to relax n minus one. +I'd say, well, + +I know how to get from s to B +with weight infinity. + +Infinity plus two I can get to +from s to E. + +Well, infinity plus two is not +much better than infinity. + +OK, so I don't do anything, +don't update this to infinity. + +I mean, infinity plus two +sounds even worse. + +But infinity plus two is +infinity. + +OK, that's the edge number one. +So, no relaxation edge number + +two, same deal as number three, +same deal, edge number four we + +start to get something +interesting because I have a + +finite value here that says I +can get from A to B using a + +total weight of minus one. +So that seems good. + +I'll write down minus one here, +and update B to minus one. + +The rest stay the same. +So, I'm just going to keep + +doing this over and over. +That was edge number four. + +Number five, +we also get a relaxation. + +Four is better than infinity. +So, c gets a number of four. + +Then we get to edge number six. +That's infinity plus five is + +worse than four. +OK, so no relaxation there. + +Edge number seven is +interesting because I have a + +finite value here minus one plus +the weight of this edge, + +which is three. +That's a total of two, + +which is actually better than +four. + +So, this route, +A, B, c is actually better than + +the route I just found a second +ago. + +So, this is now a two. +This is all happening in one + +iteration of the main loop. +We actually found two good + +paths to c. +We found one better than the + +other. +OK, and that was edge number + +seven, and edge number eight is +over here. + +It doesn't matter. +OK, so that was round one of + +this outer loop, +so, the first value of i. + +i equals one. +OK, now we continue. + +Just keep going. +So, we start with edge number + +one. +Now, minus one plus two is one. + +That's better than infinity. +It'll start speeding up. + +It's repetitive. +It's actually not too much + +longer until we're done. +Number two, this is an infinity + +so we don't do anything. +Number three: + +minus one plus two is one; +better than infinity. + +This is vertex d, +and it's number three. + +Number four we've already done. +Nothing changed. + +Number five: +this is where we see the path + +four again, but that's worse +than two. + +So, we don't update anything. +Number six: one plus five is + +six, which is bigger than two, +so no good. + +Go around this way. +Number seven: + +same deal. +Number eight is interesting. + +So, we have a weight of one +here, a weight of minus three + +here. +So, the total is minus two, + +which is better than one. +So, that was d. + +And, I believe that's it. +So that was definitely the end + +of that round. +So, it's I plus two because we + +just looked at the eighth edge. +And, I'll cheat and check. + +Indeed, that is the last thing +that happens. + +We can check the couple of +outgoing edges from d because + +that's the only one whose value +just changed. + +And, there are no more +relaxations possible. + +So, that was in two rounds. +The claim is we got all the + +shortest path weights. +The algorithm would actually + +loop four times to guarantee +correctness because we have five + +vertices here and one less than +that. + +So, in fact, +in the execution here there are + +two more blank rounds at the +bottom. + +Nothing happens. +But, what the hell? + +OK, so that is Bellman-Ford. +I mean, it's certainly not + +doing anything wrong. +The question is, + +why is it guaranteed to +converge in V minus one steps + +unless there is a negative +weight cycle? + +Question? + +Right, so that's an +optimization. + +If you discover a whole round, +and nothing happens, + +so you can keep track of that +in the algorithm thing, + +you can stop. +In the worst case, + +it won't make a difference. +But in practice, + +you probably want to do that. +Yeah? + +Good question. +All right, so some simple + +observations, +I mean, we're only doing + +relaxation. +So, we can use a lot of our + +analysis from before. +In particular, + +the d values are only +decreasing monotonically. + +As we cross out values here, +we are always making it + +smaller, which is good. +Another nifty thing about this + +algorithm is that you can run it +even in a distributed system. + +If this is some actual network, +some computer network, + +and these are machines, +and they're communicating by + +these links, I mean, +it's a purely local thing. + +Relaxation is a local thing. +You don't need any global + +strategy, and you're asking +about, can we do a different + +order in each step? +Well, yeah, you could just keep + +relaxing edges, +and keep relaxing edges, + +and just keep going for the +entire lifetime of the network. + +And eventually, +you will find shortest paths. + +So, this algorithm is +guaranteed to finish in V rounds + +in a distributed system. +It might be more asynchronous. + +And, it's a little harder to +analyze. + +But it will still work +eventually. + +It's guaranteed to converge. +And so, Bellman-Ford is used in + +the Internet for finding +shortest paths. + +OK, so let's finally prove that +it works. + +This should only take a couple +of boards. + +So let's suppose we have a +graph and some edge weights that + +have no negative weight cycles. +Then the claim is that we + +terminate with the correct +answer. + +So, Bellman-Ford terminates +with all of these d of v values + +set to the delta values for +every vertex. + +OK, the proof is going to be +pretty immediate using the + +lemmas that we had from before +if you remember them. + +So, we're just going to look at +every vertex separately. + +So, I'll call the vertex v. +The claim is that this holds by + +the end of the algorithm. +So, remember what we need to + +prove is that at some point, +d of v equals delta of s comma + +v because we know it decreases +monotonically, + +and we know that it never gets +any smaller than the correct + +value because relaxations are +always safe. + +So, we just need to show at +some point this holds, + +and that it will hold at the +end. + +So, by monotonicity of the d +values, and by correctness part + +one, which was that the d of v's +are always greater than or equal + +to the deltas, +we only need to show that at + +some point we have equality. + +So that's our goal. +So what we're going to do is + +just look at v, +and the shortest path to v, + +and see what happens to the +algorithm relative to that path. + +So, I'm going to name the path. +Let's call it p. + +It starts at vertex v_0 and +goes to v_1, v_2, + +whatever, and ends at v_k. +And, this is not just any + +shortest path, +but it's one that starts at s. + +So, v_0's s, +and it ends at v. + +So, I'm going to give a couple +of names to s and v so I can + +talk about the path more +uniformly. + +So, this is a shortest path +from s to v. + +Now, I also want it to be not +just any shortest path from s to + +v, but among all shortest paths +from s to v I want it to be one + +with the fewest possible edges. + +OK, so shortest here means in +terms of the total weight of the + +path. +Subject to being shortest in + +weight, I wanted to also be +shortest in the number of edges. + +And, the reason I want that is +to be able to conclude that p is + +a simple path, +meaning that it doesn't repeat + +any vertices. +Now, can anyone tell me why I + +need to assume that the number +of edges is the smallest + +possible in order to guarantee +that p is simple? + +The claim is that not all +shortest paths are necessarily + +simple. +Yeah? + +Right, I can have a zero weight +cycle, exactly. + +So, we are hoping, +I mean, in fact in the theorem + +here, we're assuming that there +are no negative weight cycles. + +But there might be zero weight +cycles still. + +As a zero weight cycle, +you can put that in the middle + +of any shortest path to make it +arbitrarily long, + +repeat vertices over and over. +That's going to be annoying. + +What I want is that p is +simple. + +And, I can guarantee that +essentially by shortcutting. + +If ever I take a zero weight +cycle, I throw it away. + +And this is one mathematical +way of doing that. + +OK, now what else do we know +about this shortest path? + +Well, we know that subpaths are +shortest paths are shortest + +paths. +That's optimal substructure. + +So, we know what the shortest +path from s to v_i is sort of + +inductively. +It's the shortest path, + +I mean, it's the weight of that +path, which is, + +in particular, +the shortest path from s to v + +minus one plus the weight of the +last edge, v minus one to v_i. + +So, this is by optimal +substructure as we proved last + +time. +OK, and I think that's pretty + +much the warm-up. +So, I want to sort of do this + +inductively in I, +start out with v zero, + +and go up to v_k. +So, the first question is, + +what is d of v_0, +which is s? + +What is d of the source? +Well, certainly at the + +beginning of the algorithm, +it's zero. + +So, let's say equals zero +initially because that's what we + +set it to. +And it only goes down from + +there. +So, it certainly, + +at most, zero. +The real question is, + +what is delta of s comma v_0. +What is the shortest path + +weight from s to s? +It has to be zero, + +otherwise you have a negative +weight cycle, + +exactly. +My favorite answer, + +zero. +So, if we had another path from + +s to s, I mean, +that is a cycle. + +So, it's got to be zero. +So, these are actually equal at + +the beginning of the algorithm, +which is great. + +That means they will be for all +time because we just argued up + +here, only goes down, +never can get too small. + +So, we have d of v_0 set to the +right thing. + +Great: good for the base case +of the induction. + +Of course, what we really care +about is v_k, + +which is v. +So, let's talk about the v_i + +inductively, and then we will +get v_k as a result. + +So, yeah, let's do it by +induction. + +That's more fun. + +Let's say that d of v_i is +equal to delta of s v_i after I + +rounds of the algorithm. +So, this is actually referring + +to the I that is in the +algorithm here. + +These are rounds. +So, one round is an entire + +execution of all the edges, +relaxation of all the edges. + +So, this is certainly true for +I equals zero. + +We just proved that. +After zero rounds, + +at the beginning of the +algorithm, d of v_0 equals delta + +of s, v_0. +OK, so now, that's not really + +what I wanted, +but OK, fine. + +Now we'll prove it for d of v_i +plus one. + +Generally, I recommend you +assume something. + +In fact, why don't I follow my +own advice and change it? + +It's usually nicer to think of +induction as recursion. + +So, you assume that this is +true, let's say, + +for j less than the i that you +care about, and then you prove + +it for d of v_i. +It's usually a lot easier to + +think about it that way. +In particular, + +you can use strong induction +for all less than i. + +Here, we're only going to need +it for one less. + +We have some relation between I +and I minus one here in terms of + +the deltas. +And so, we want to argue + +something about the d values. +OK, well, let's think about + +what's going on here. +We know that, + +let's say, after I minus one +rounds, we have this inductive + +hypothesis, d of v_i minus one +equals delta of s v_i minus one. + +And, we want to conclude that +after i rounds, + +so we have one more round to do +this. + +We want to conclude that d of +v_i has the right answer, + +delta of s comma v_i. +Does that look familiar at all? + +So we want to relax every edge +in this round. + +In particular, +at some point, + +we have to relax the edge from +v_i minus one to v_i. + +We know that this path consists +of edges. + +That's the definition of a +path. + +So, during the i'th round, +we relax every edge. + +So, we better relax v_i minus +one v_i. + +And, what happens then? +It's a test of memory. + +Quick, the Death Star is +approaching. + +So, if we have the correct +value for v_i minus one, + +that we relax an outgoing edge +from there, and that edge is an + +edge of the shortest path from s +to v_i. + +What do we know? +d of v_i becomes the correct + +value, delta of s comma v_i. +This was called correctness + +lemma last time. +One of the things we proved + +about Dijkstra's algorithm, +but it was really just a fact + +about relaxation. +And it was a pretty simple + +proof. +And it comes from this fact. + +We know the shortest path +weight is this. + +So, certainly d of v_i was at +least this big, + +and let's suppose it's greater, +or otherwise we were done. + +We know d of v_i minus one is +set to this. + +And so, this is exactly the +condition that's being checked + +in the relaxation step. +And, the d of v_i value will be + +greater than this, +let's suppose. + +And then, we'll set it equal to +this. + +And that's exactly d of s v_i. +So, when we relax that edge, + +we've got to set it to the +right value. + +So, this is the end of the +proof, right? + +It's very simple. +The point is, + +you look at your shortest path. +Here it is. + +And if we assume there's no +negative weight cycles, + +this has the correct value +initially. + +d of s is going to be zero. +After the first round, + +you've got to relax this edge. +And then you get the right + +value for that vertex. +After the second round, + +you've got to relax this edge, +which gets you the right d + +value for this vertex and so on. +And so, no matter which + +shortest path you take, +you can apply this analysis. + +And you know that by, +if the length of this path, + +here we assumed it was k edges, +then after k rounds you've got + +to be done. +OK, so this was not actually + +the end of the proof. +Sorry. + +So this means after k rounds, +we have the right answer for + +v_k, which is v. +So, the only question is how + +big could k be? +And, it better be the right + +answer, at most, +v minus one is the claim by the + +algorithm that you only need to +do v minus one steps. + +And indeed, the number of edges +in a simple path in a graph is, + +at most, the number of vertices +minus one. + +k is, at most, +v minus one because p is + +simple. +So, that's why we had to assume + +that it wasn't just any shortest +path. + +It had to be a simple one so it +didn't repeat any vertices. + +So there are, +at most, V vertices in the + +path, so at most, +V minus one edges in the path. + +OK, and that's all there is to +Bellman-Ford. + +So: pretty simple in +correctness. + +Of course, we're using a lot of +the lemmas that we proved last + +time, which makes it easier. +OK, a consequence of this + +theorem, or of this proof is +that if Bellman-Ford fails to + +converge, and that's what the +algorithm is checking is whether + +this relaxation still requires +work after these d minus one + +steps. +Right, the end of this + +algorithm is run another round, +a V'th round, + +see whether anything changes. +So, we'll say that the + +algorithm fails to converge +after V minus one steps or + +rounds. +Then, there has to be a + +negative weight cycle. +OK, this is just a + +contrapositive of what we +proved. + +We proved that if you assume +there's no negative weight + +cycle, then we know that d of s +is zero, and then all this + +argument says is you've got to +converge after v minus one + +rounds. +There can't be anything left to + +do once you've reached the +shortest path weights because + +you're going monotonically; +you can never hit the bottom. + +You can never go to the floor. +So, if you fail to converge + +somehow after V minus one +rounds, you've got to have + +violated the assumption. +The only assumption we made was + +there's no negative weight +cycle. + +So, this tells us that +Bellman-Ford is actually + +correct. +When it says that there is a + +negative weight cycle, +it indeed means it. + +It's true. +OK, and you can modify + +Bellman-Ford in that case to +sort of run a little longer, + +and find where all the minus +infinities are. + +And that is, +in some sense, + +one of the things you have to +do in your problem set, + +I believe. +So, I won't cover it here. + +But, it's a good exercise in +any case to figure out how you + +would find where the minus +infinities are. + +What are all the vertices +reachable from negative weight + +cycle? +Those are the ones that have + +minus infinities. +OK, so you might say, + +well, that was awfully fast. +Actually, it's not over yet. + +The episode is not yet ended. +We're going to use Bellman-Ford + +to solve the even bigger and +greater shortest path problems. + +And in the remainder of today's +lecture, we will see it applied + +to a more general problem, +in some sense, + +called linear programming. +And the next lecture, + +we'll really use it to do some +amazing stuff with all pairs + +shortest paths. +Let's go over here. + +So, our goal, +although it won't be obvious + +today, is to be able to compute +the shortest paths between every + +pair of vertices, +which we could certainly do at + +this point just by running +Bellman-Ford v times. + +OK, but we want to do better +than that, of course. + +And, that will be the climax of +the trilogy. + +OK, today we just discovered +who Luke's father is. + +So, it turns out the father of +shortest paths is linear + +programming. +Actually, simultaneously the + +father and the mother because +programs do not have gender. + +OK, my father likes to say, +we both took improv comedy + +lessons so we have degrees in +improvisation. + +And he said, +you know, we went to improv + +classes in order to learn how to +make our humor better. + +And, the problem is, +it didn't actually make our + +humor better. +It just made us less afraid to + +use it. +[LAUGHTER] So, + +you are subjected to all this +improv humor. + +I didn't see the connection of +Luke's father, + +but there you go. +OK, so, linear programming is a + +very general problem, +a very big tool. + +Has anyone seen linear +programming before? + +OK, one person. +And, I'm sure you will, + +at some time in your life, +do anything vaguely computing + +optimization related, +linear programming comes up at + +some point. +It's a very useful tool. + +You're given a matrix and two +vectors: not too exciting yet. + +What you want to do is find a +vector. + +This is a very dry description. +We'll see what makes it so + +interesting in a moment. + +So, you want to maximize some +objective, and you have some + +constraints. +And they're all linear. + +So, the objective is a linear +function in the variables x, + +and your constraints are a +bunch of linear constraints, + +inequality constraints, +that's one makes an + +interesting. +It's not just solving a linear + +system as you've seen in linear +algebra, or whatever. + +Or, of course, +it could be that there is no + +such x. +OK: vaguely familiar you might + +think to the theorem about +Bellman-Ford. + +And, we'll show that there's +some kind of connection here + +that either you want to find +something, or show that it + +doesn't exist. +Well, that's still a pretty + +vague connection, +but I also want to maximize + +something, or are sort of +minimize the shortest paths, + +OK, somewhat similar. +We have these constraints. + +So, yeah. +This may be intuitive to you, + +I don't know. +I prefer a more geometric + +picture, and I will try to draw +such a geometric picture, + +and I've never tried to do this +on a blackboard, + +so it should be interesting. +I think I'm going to fail + +miserably. +It sort of looks like a + +dodecahedron, +right? + +Sort of, kind of, +not really. + +A bit rough on the bottom, +OK. + +So, if you have a bunch of +linear constraints, + +this is supposed to be in 3-D. +Now I labeled it. + +It's now in 3-D. +Good. + +So, you have these linear +constraints. + +That turns out to define +hyperplanes in n dimensions. + +OK, so you have this base here +that's three-dimensional space. + +So, n equals three. +And, these hyperplanes, + +if you're looking at one side +of the hyperplane, + +that's the less than or equal +to, if you take the + +intersection, +you get some convex polytope or + +polyhedron. +In 3-D, you might get a + +dodecahedron or whatever. +And, your goal, + +you have some objective vector +c, let's say, + +up. +Suppose that's the c vector. + +Your goal is to find the +highest point in this polytope. + +So here, it's maybe this one. +OK, this is the target. + +This is the optimal, +x. + +That is the geometric view. +If you prefer the algebraic + +view, you want to maximize the c +transpose times x. + +So, this is m. +This is n. + +Check out the dimensions work +out. + +So that's saying you want to +maximize the dot product. + +You want to maximize the extent +to which x is in the direction + +c. +And, you want to maximize that + +subject to some constraints, +which looks something like + +this, maybe. +So, this is A, + +and it's m by n. +You want to multiply it by, + +it should be something of +height n. + +That's x. +Let me put x down here, + +n by one. +And, it should be less than or + +equal to something of this +height, which is B, + +the right hand side. +OK, that's the algebraic view, + +which is to check out all the +dimensions are working out. + +But, you can read these off in +each row here, + +when multiplied by this column, +gives you one value here. + +And as just a linear +constraints on all the x sides. + +So, you want to maximize this +linear function of x_1 up to x_n + +subject to these constraints, +OK? + +Pretty simple, +but pretty powerful in general. + +So, it turns out that with, +you can formulate a huge number + +of problems such as shortest +paths as a linear program. + +So, it's a general tool. +And in this class, + +we will not cover any +algorithms for solving linear + +programming. +It's a bit tricky. + +I'll just mention that they are +out there. + +So, there's many efficient +algorithms, and lots of code + +that does this. +It's a very practical setup. + +So, lots of algorithms to solve +LP's, linear programs. + +Linear programming is usually +called LP. + +And, I'll mention a few of +them. + +There's the simplex algorithm. +This is one of the first. + +I think it is the first, +the ellipsoid algorithm. + +There's interior point methods, +and there's random sampling. + +I'll just say a little bit +about each of these because + +we're not going to talk about +any of them in depth. + +The simplex algorithm, +this is, I mean, + +one of the first algorithms in +the world in some sense, + +certainly one of the most +popular. + +It's still used today. +Almost all linear programming + +code uses the simplex algorithm. +It happens to run an + +exponential time in the +worst-case, so it's actually + +pretty bad theoretically. +But in practice, + +it works really well. +And there is some recent work + +that tries to understand this. +It's still exponential in the + +worst case. +But, it's practical. + +There's actually an open +problem whether there exists a + +variation of simplex that runs +in polynomial time. + +But, I won't go into that. +That's a major open problem in + +this area of linear programming. +The ellipsoid algorithm was the + +first algorithm to solve linear +programming in polynomial time. + +So, for a long time, +people didn't know. + +Around this time, +people started realizing + +polynomial time is a good thing. +That happened around the late + +60s. +Polynomial time is good. + +And, the ellipsoid algorithm is +the first one to do it. + +It's a very general algorithm, +and very powerful, + +theoretically: +completely impractical. + +But, it's cool. +It lets you do things like you + +can solve a linear program that +has exponentially many + +constraints in polynomial time. +You've got all sorts of crazy + +things. +So, I'll just say it's + +polynomial time. +I can't say something nice + +about it; don't say it at all. +It's impractical. + +Interior point methods are sort +of the mixture. + +They run in polynomial time. +You can guarantee that. + +And, they are also pretty +practical, and there's sort of + +this competition these days +about whether simplex or + +interior point is better. +And, I don't know what it is + +today but a few years ago they +were neck and neck. + +And, random sampling is a brand +new approach. + +This is just from a couple +years ago by two MIT professors, + +Dimitris Bertsimas and Santosh +Vempala, I guess the other is in + +applied math. +So, just to show you, + +there's active work in this +area. + +People are still finding new +ways to solve linear programs. + +This is completely randomized, +and very simple, + +and very general. +It hasn't been implemented, + +so we don't know how practical +it is yet. + +But, it has potential. +OK: pretty neat. + +OK, we're going to look at a +somewhat simpler version of + +linear programming. +The first restriction we are + +going to make is actually not +much of a restriction. + +But, nonetheless we will +consider it, it's a little bit + +easier to think about. +So here, we had some polytope + +we wanted to maximize some +objective. + +In a feasibility problem, +I just want to know, + +is the polytope empty? +Can you find any point in that + +polytope? +Can you find any set of values, + +x, that satisfy these +constraints? + +OK, so there's no objective. +c, just find x such that AX is + +less than or equal to B. +OK, it turns out you can prove + +a very general theorem that if +you can solve linear + +feasibility, you can also solve +linear programming. + +We won't prove that here, +but this is actually no easier + +than the original problem even +though it feels easier, + +and it's easier to think about. +I was just saying actually no + +easier than LP. +OK, the next restriction we're + +going to make is a real +restriction. + +And it simplifies the problem +quite a bit. + +And that's to look at different +constraints. + +And, if all this seemed a bit +abstract so far, + +we will now ground ourselves +little bit. + +A system of different +constraints is a linear + +feasibility problem. +So, it's an LP where there's no + +objective. +And, it's with a restriction, + +so, where each row of the +matrix, so, the matrix, + +A, has one one, +and it has one minus one, + +and everything else in the row +is zero. + +OK, in other words, +each constraint has its very + +simple form. +It involves two variables and + +some number. +So, we have something like x_j + +minus x_i is less than or equal +to w_ij. + +So, this is just a number. +These are two variables. + +There's a minus sign, +no values up here, + +no coefficients, +no other of the X_k's appear, + +just two of them. +And, you have a bunch of + +constraints of this form, +one per row of the matrix. + +Geometrically, +I haven't thought about what + +this means. +I think it means the + +hyperplanes are pretty simple. +Sorry I can't do better than + +that. +It's a little hard to see this + +in high dimensions. +But, it will start to + +correspond to something we've +seen, namely the board that its + +next to, very shortly. +OK, so let's do a very quick + +example mainly to have something +to point at. + +Here's a very simple system of +difference constraints -- + +-- OK, and a solution. +Why not? + +It's not totally trivial to +solve this, but here's a + +solution. +And the only thing to check is + +that each of these constraints +is satisfied. + +x_1 minus x_2 is three, +which is less than or equal to + +three, and so on. +There could be negative values. + +There could be positive values. +It doesn't matter. + +I'd like to transform this +system of difference constraints + +into a graph because we know a +lot about graphs. + +So, we're going to call this +the constraint graph. + +And, it's going to represent +these constraints. + +How'd I do it? +Well, I take every constraint, + +which in general looks like +this, and I convert it into an + +edge. +OK, so if I write it as x_j + +minus x_i is less than or equal +to some w_ij, + +w seems suggestive of weights. +That's exactly why I called it + +w. +I'm going to make that an edge + +from v_i to v_j. +So, the order flips a little + +bit. +And, the weight of that edge is + +w_ij. +So, just do that. + +Make n vertices. +So, you have the number of + +vertices equals n. +The number of edges equals the + +number of constraints, +which is m, the height of the + +matrix, and just transform. +So, for example, + +here we have three variables. +So, we have three vertices, + +v_1, v_2, v_3. +We have x_1 minus x_2. + +So, we have an edge from v_2 to +v_1 of weight three. + +We have x_2 minus x_3. +So, we have an edge from v_3 to + +v_2 of weight minus two. +And, we have x_1 minus x_3. + +So, we have an edge from v_3 to +v_1 of weight two. + +I hope I got the directions +right. + +Yep. +So, there it is, + +a graph: currently no obvious +connection to shortest paths, + +right? +But in fact, + +this constraint is closely +related to shortest paths. + +So let me just rewrite it. +You could say, + +well, an x_j is less than or +equal to x_i plus w_ij. + +Or, you could think of it as +d[j] less than or equal to d[i] + +plus w_ij. +This is a conceptual balloon. + +Look awfully familiar? +A lot like the triangle + +inequality, a lot like +relaxation. + +So, there's a very close +connection between these two + +problems as we will now prove. + +So, we're going to have two +theorems. + +And, they're going to look +similar to the correctness of + +Bellman-Ford in that they talk +about negative weight cycles. + +Here we go. +It turns out, + +I mean, we have this constraint +graph. + +It can have negative weights. +It can have positive weights. + +It turns out what matters is if +you have a negative weight + +cycle. +So, the first thing to prove is + +that if you have a negative +weight cycle that something bad + +happens. +OK, what could happen bad? + +Well, we're just trying to +satisfy this system of + +constraints. +So, the bad thing is that there + +might not be any solution. +These constraints may be + +infeasible. +And that's the claim. + +The claim is that this is +actually an if and only if. + +But first we'll proved the if. +If you have a negative weight + +cycle, you're doomed. +The difference constraints are + +unsatisfiable. +That's a more intuitive way to + +say it. +In the LP world, + +they call it infeasible. +But unsatisfiable makes a lot + +more sense. +There's no way to assign the + +x_i's in order to satisfy all +the constraints simultaneously. + +So, let's just take a look. +Consider a negative weight + +cycle. +It starts at some vertex, + +goes through some vertices, +and at some point comes back. + +I don't care whether it repeats +vertices, just as long as this + +cycle, from v_1 to v_1 is a +negative weight cycle strictly + +negative weight. + +OK, and what I'm going to do is +just write down all the + +constraints. +Each of these edges corresponds + +to a constraint, +which must be in the set of + +constraints because we had that +graph. + +So, these are all edges. +Let's look at what they give + +us. +So, we have an edge from v_1 to + +v_2. +That corresponds to x_2 minus + +x_1 is, at most, +something, w_12. + +Then we have x_3 minus x_2. +That's the weight w_23, + +and so on. +And eventually we get up to + +something like x_k minus +x_(k-1). + +That's this edge: +w_(k-1),k , and lastly we have + +this edge, which wraps around. +So, it's x_1 minus x_k, + +w_k1 if I've got the signs +right. + +Good, so here's a bunch of +constraints. + +What do you suggest I do with +them? + +Anything interesting about +these constraints, + +say, the left hand sides? +Sorry? + +It sounded like the right word. +What was it? + +Telescopes, yes, +good. + +Everything cancels. +If I added these up, + +there's an x_2 and a minus x_2. +There's a minus x_1 and an x_1. + +There's a minus XK and an XK. +Everything here cancels if I + +add up the left hand sides. +So, what happens if I add up + +the right hand sides? +Over here I get zero, + +my favorite answer. +And over here, + +we get all the weights of all +the edges in the negative weight + +cycle, which is the weight of +the cycle, which is negative. + +So, zero is strictly less than +zero: contradiction. + +Contradiction: +wait a minute, + +we didn't assume anything that +was false. + +So, it's not really a +contradiction in the + +mathematical sense. +We didn't contradict the world. + +We just said that these +constraints are contradictory. + +In other words, +if you pick any values of the + +x_i's, there is no way that +these can all be true because + +that you would get a +contradiction. + +So, it's impossible for these +things to be satisfied by some + +real x_i's. +So, these must be + +unsatisfiable. +Let's say there's no satisfying + +assignment, a little more +precise, x_1 up to x_m, + +no weights. +Can we satisfy those + +constraints? +Because they add up to zero on + +the left-hand side, +and negative on the right-hand + +side. +OK, so that's an easy proof. + +The reverse direction will be +only slightly harder. + +OK, so, cool. +We have this connection. + +So motivation is, +suppose you'd want to solve + +these difference constraints. +And we'll see one such + +application. +I Googled around for difference + +constraints. +There is a fair number of + +papers that care about +difference constraints. + +And, they all use shortest +paths to solve them. + +So, if we can prove a +connection between shortest + +paths, which we know how to +compute, and difference + +constraints, then we'll have +something cool. + +And, next class will see even +more applications of difference + +constraints. +It turns out they're really + +useful for all pairs shortest +paths. + +OK, but for now let's just +prove this equivalence and + +finish it off. +So, the reverse direction is if + +there's no negative weight cycle +in this constraint graph, + +then the system better be +satisfiable. + +The claim is that these +negative weight cycles are the + +only barriers for finding a +solution to these difference + +constraints. +I have this feeling somewhere + +here. +I had to talk about the + +constraint graph. +Good. + +Satisfied, good. +So, here we're going to see a + +technique that is very useful +when thinking about shortest + +paths. +And, it's a bit hard to guess, + +especially if you haven't seen +it before. + +This is useful in problem sets, +and in quizzes, + +and finals, and everything. +So, keep this in mind. + +I mean, I'm using it to prove +this rather simple theorem, + +but the idea of changing the +graph, so I'm going to call this + +constraint graph G. +Changing the graph is a very + +powerful idea. +So, we're going to add a new + +vertex, s, or source, +use the source, + +Luke, and we're going to add a +bunch of edges from s because + +being a source, +it better be connected to some + +things. +So, we are going to add a zero + +weight edge, or weight zero edge +from s to everywhere, + +so, to every other vertex in +the constraint graph. + +Those vertices are called v_i, +v_1 up to v_n. + +So, I have my constraint graph. +But I'll copy this one so I can + +change it. +It's always good to backup your + +work before you make changes, +right? + +So now, I want to add a new +vertex, s, over here, + +my new source. +I just take my constraint + +graph, whatever it looks like, +add in weight zero edges to all + +the other vertices. +Simple enough. + +Now, what did I do? +What did you do? + +Well, I have a candidate source +now which can reach all the + +vertices. +So, shortest path from s, + +hopefully, well, +paths from s exist. + +I can get from s to everywhere +in weight at most zero. + +OK, maybe less. +Could it be less? + +Well, you know, +like v_2, I can get to it by + +zero minus two. +So, that's less than zero. + +So I've got to be a little +careful. + +What if there's a negative +weight cycle? + +Oh no? +Then there wouldn't be any + +shortest paths. +Fortunately, + +we assume that there's no +negative weight cycle in the + +original graph. +And if you think about it, + +if there's no negative weight +cycle in the original graph, + +we add an edge from s to +everywhere else. + +We're not making any new +negative weight cycles because + +you can start at s and go +somewhere at a cost of zero, + +which doesn't affect any +weights. + +And then, you are forced to +stay in the old graph. + +So, there can't be any new +negative weight cycles. + +So, the modified graph has no +negative weight cycles. + +That's good because it also has +paths from s, + +and therefore it also has +shortest paths from s. + +The modified graph has no +negative weight because it + +didn't before. +And, it has paths from s. + +There's a path from s to every +vertex. + +There may not have been before. +Before, I couldn't get from v_2 + +to v_3, for example. +Well, that's still true. + +But from s I can get to +everywhere. + +So, that means that this graph, +this modified graph, + +has shortest paths. +Shortest paths exist from s. + +In other words, +if I took all the shortest path + +weights, like I ran Bellman-Ford +from s, then, + +I would get a bunch of finite +numbers, d of v, + +for every value, +for every vertex. + +That seems like a good idea. +Let's do it. + +So, shortest paths exist. +Let's just assign x_i to be the + +shortest path weight from s to +v_i. + +Why not? +That's a good choice for a + +number, the shortest path weight +from s to v_i. + +This is finite because it's +less than infinity, + +and it's greater than minus +infinity, so, + +some finite number. +That's what we need to do in + +order to satisfy these +constraints. + +The claim is that this is a +satisfying assignment. + +Why? +Triangle inequality. + +Somewhere here we wrote +triangle inequality. + +This looks a lot like the +triangle inequality. + +In fact, I think that's the end +of the proof. + +Let's see here. +What we want to be true with + +this assignment is that x_j +minus x_i is less than or equal + +to w_ij whenever ij is an edge. +Or, let's say v_i, + +v_j, for every such constraint, +so, for v_i, + +v_j in the edge set. +OK, so what is this true? + +Well, let's just expand it out. +So, x_i is this delta, + +and x_j is some other delta. +So, we have delta of s, + +vj minus delta of s_vi. +And, on the right-hand side, + +well, w_ij, that was the weight +of the edge from I to J. + +So, this is the weight of v_i +to v_j. + +OK, I will rewrite this +slightly. + +Delta s, vj is less than or +equal to delta s, + +vi plus w of v_i, +v_j. + +And that's the triangle +inequality more or less. + +The shortest path from s to v_j +is, at most, shortest path from + +s to v_i plus a particular path +from v_i to v_j, + +namely the single edge v_i to +v_j. + +This could only be longer than +the shortest path. + +And so, that makes the +right-hand side bigger, + +which makes this inequality +more true, meaning it was true + +before. +And now it's still true. + +And, that proves it. +This is true. + +And, these were all equivalent +statements. + +This we know to be true by +triangle inequality. + +Therefore, these constraints +are all satisfied. + +Magic. +I'm so excited here. + +So, we've proved that having a +negative weight cycle is exactly + +when these system of difference +constraints are unsatisfiable. + +So, if we want to satisfy them, +if we want to find the right + +answer to x, we run +Bellman-Ford. + +Either it says, +oh, no negative weight cycle. + +Then you are hosed. +Then, there is no solution. + +But that's the best you could +hope to know. + +Otherwise, it says, +oh, there was no negative + +weight cycle, +and here are your shortest path + +weights. +You just plug them in, + +and bam, you have your x_i's +that satisfy the constraints. + +Awesome. +Now, it wasn't just any graph. + +I mean, we started with +constraints, algebra, + +we converted it into a graph by +this transform. + +Then we added a source vertex, +s. + +So, I mean, we had to build a +graph to solve our problem, + +very powerful idea. +Cool. + +This is the idea of reduction. +You can reduce the problem you + +want to solve into some problem +you know how to solve. + +You know how to solve shortest +paths when there are no negative + +weight cycles, +or find out that there is a + +negative weight cycle by +Bellman-Ford. + +So, now we know how to solve +difference constraints. + +It turns out you can do even +more. + +Bellman-Ford does a little bit +more than just solve these + +constraints. +But first let me write down + +what I've been jumping up and +down about. + +The corollary is you can use +Bellman-Ford. + +I mean, you make this graph. +Then you apply Bellman-Ford, + +and it will solve your system +of difference constraints. + +So, let me put in some numbers +here. + +You have m difference +constraints. + +And, you have n variables. +And, it will solve them in + +order m times n time. +Actually, these numbers go up + +slightly because we are adding n +edges, and we're adding one + +vertex, but assuming all of +these numbers are nontrivial, + +m is at least n. +It's order MN time. + +OK, trying to avoid cases where +some of them are close to zero. + +Good. +So, some other facts, + +that's what I just said. +And we'll leave these as + +exercises because they're not +too essential. + +The main thing we need is this. +But, some other cool facts is + +that Bellman-Ford actually +optimizes some objective + +functions. +So, we are saying it's just a + +feasibility problem. +We just want to know whether + +these constraints are +satisfiable. + +In fact, you can add a +particular objective function. + +So, you can't give it an +arbitrary objective function, + +but here's one of interest. +x_1 plus x_2 plus x_n, + +OK, but not just that. +We have some constraints. + +OK, this is a linear program. +I want to maximize the sum of + +the x_i's subject to all the +x_i's being nonpositive and the + +difference constraints. +So, this we had before. + +This is fine. +We noticed at some point you + +could get from s to everywhere +with cost, at most, + +zero. +So, we know that in this + +assignment all of the x_i's are +negative. + +That's not necessary, +but it's true when you run + +Bellman-Ford. +So if you solve your system + +using Bellman-Ford, +which is no less general than + +anything else, +you happen to get nonpositive + +x_i's. +And so, subject to that + +constraint, it actually makes +them is close to zero as + +possible in the L1 norm. +In the sum of these values, + +it tries to make the sum as +close to zero, + +it tries to make the values as +small as possible in absolute + +value in this sense. +OK, it does more than that. + +It cooks, it cleans, +it finds shortest paths. + +It also minimizes the spread, +the maximum over all i of x_i + +minus the minimum over all i of +x_i. + +So, I mean, if you have your +real line, and here are the + +x_i's wherever they are. +It minimizes this distance. + +And zero is somewhere over +here. + +So, it tries to make the x_i's +as compact as possible. + +This is actually the L infinity +norm, if you know stuff about + +norms from your linear algebra +class. + +OK, this is the L1 norm. +I think it minimizes every LP + +norm. +Good, so let's use this for + +something. +Yeah, let's solve a real + +problem, and then we'll be done +for today. + +Next class we'll see the really +cool stuff, the really cool + +application of all of this. +For now, and we'll see a cool + +but relatively simple +application, which is VLSI + +layout. +We talked a little bit about + +VLSI way back and divide and +conquer. + +You have a bunch of chips, +or you want to arrange them, + +and minimize some objectives. +So, here's a particular, + +tons of problems that come out +of VLSI layout. + +Here's one of them. +You have a bunch of features of + +an integrated circuit. +You want to somehow arrange + +them on your circuit without +putting any two of them too + +close to each other. +You have some minimum + +separation like at least they +should not get top of each + +other. +Probably, you also need some + +separation to put wires in +between, and so on, + +so, without putting any two +features too close together. + +OK, so just to give you an +idea, so I have some objects and + +I'm going to be a little bit +vague about how this works. + +You have some features. +This is stuff, + +some chips, whatever. +We don't really care what their + +shapes look like. +I just want to be able to move + +them around so that the gap at +any point, so let me just think + +about this gap. +This gap should be at least + +some delta. +Or, I don't want to use delta. + +Let's say epsilon, +good, small number. + +So, I just need some separation +between all of my parts. + +And for this problem, +I'm going to be pretty simple, + +just say that the parts are +only allowed to slide + +horizontally. +So, it's a one-dimensional + +problem. +These objects are in 2-d, + +or whatever, +but I can only slide them an x + +coordinate. +So, to model that, + +I'm going to look at the left +edge of every part and say, + +well, these two left edges +should be at least some + +separation. +So, I think of it as whatever + +the distance is plus some +epsilon. + +But, you know, +if you have some funky 2-d + +shapes you have to compute, +well, this is a little bit too + +close because these come into +alignment. + +But, there's some constraint, +well, for any two pieces, + +I could figure out how close +they can get. + +They should get no closer. +So, I'm going to call this x_1. + +I'll call this x_2. +So, we have some constraint + +like x_2 minus x_1 is at least d +plus epsilon, + +or whatever you compute that +weight to be. + +OK, so for every pair of +pieces, I can do this, + +compute some constraint on how +far apart they have to be. + +And, now I'd like to assign +these x coordinates. + +Right now, I'm assuming they're +just variables. + +I want to slide these pieces +around horizontally in order to + +compactify them as much as +possible so they fit in the + +smallest chip that I can make +because it costs money, + +and time, and everything, +and power, everything. + +You always want your chip +small. + +So, Bellman-Ford does that. +All right, so Bellman-Ford + +solves these constraints because +it's just a bunch of difference + +constraints. +And we know that they are + +solvable because you could +spread all the pieces out + +arbitrarily far. +And, it minimizes the spread, + +minimizes the size of the chip +I need, a max of x_i minus the + +min of x_i. +So, this is it maximizes + +compactness, or minimizes size +of the chip. + +OK, this is a one-dimensional +problem, so it may seem a little + +artificial, but the two +dimensional problem is really + +hard to solve. +And this is, + +in fact, the best you can do +with a nice polynomial time + +algorithm. +There are other applications if + +you're scheduling events in, +like, a multimedia environment, + +and you want to guarantee that +this audio plays at least two + +seconds after this video, +but then there are things that + +are playing at the same time, +and they have to be within some + +gap of each other, +so, lots of papers about using + +Bellman-Ford, +solve difference constraints to + +enable multimedia environments. +OK, so there you go. + +And next class we'll see more +applications of Bellman-Ford to + +all pairs shortest paths. +Questions? + +Great. \ No newline at end of file diff --git a/Tw1k46ywN6E.txt b/Tw1k46ywN6E.txt new file mode 100644 index 0000000000000000000000000000000000000000..6f5f457bfaa20a4adba56d435864cf855a5c60d1 --- /dev/null +++ b/Tw1k46ywN6E.txt @@ -0,0 +1,13109 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit mitop courseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu all right good morning + + align:start position:0% +ocw.mit.edu all right good morning + + + align:start position:0% +ocw.mit.edu all right good morning +everyone thanks for coming on quiz day I + + align:start position:0% +everyone thanks for coming on quiz day I + + + align:start position:0% +everyone thanks for coming on quiz day I +have to have someone to throw frisbees + + align:start position:0% +have to have someone to throw frisbees + + + align:start position:0% +have to have someone to throw frisbees +to you know Empty Chairs uh would be + + align:start position:0% +to you know Empty Chairs uh would be + + + align:start position:0% +to you know Empty Chairs uh would be +difficult uh so we're going to be doing + + align:start position:0% +difficult uh so we're going to be doing + + + align:start position:0% +difficult uh so we're going to be doing +dynamic programming a notion you've + + align:start position:0% +dynamic programming a notion you've + + + align:start position:0% +dynamic programming a notion you've +learned uh in + + align:start position:0% +learned uh in + + + align:start position:0% +learned uh in +66 we look at three different examples + + align:start position:0% +66 we look at three different examples + + + align:start position:0% +66 we look at three different examples +today the first one is uh really at the + + align:start position:0% +today the first one is uh really at the + + + align:start position:0% +today the first one is uh really at the +level of6 a cute little problem on + + align:start position:0% +level of6 a cute little problem on + + + align:start position:0% +level of6 a cute little problem on +finding the longest palindromic sequence + + align:start position:0% +finding the longest palindromic sequence + + + align:start position:0% +finding the longest palindromic sequence +um inside of a longer sequence sometimes + + align:start position:0% +um inside of a longer sequence sometimes + + + align:start position:0% +um inside of a longer sequence sometimes +it's called longest palindromic + + align:start position:0% +it's called longest palindromic + + + align:start position:0% +it's called longest palindromic +subsequence and uh as we'll talk about a + + align:start position:0% +subsequence and uh as we'll talk about a + + + align:start position:0% +subsequence and uh as we'll talk about a +subsequence means that uh it can be + + align:start position:0% +subsequence means that uh it can be + + + align:start position:0% +subsequence means that uh it can be +non-contiguous so you could uh you could + + align:start position:0% +non-contiguous so you could uh you could + + + align:start position:0% +non-contiguous so you could uh you could +skip uh letters uh in a sequence of + + align:start position:0% +skip uh letters uh in a sequence of + + + align:start position:0% +skip uh letters uh in a sequence of +letters uh and it it it would you would + + align:start position:0% +letters uh and it it it would you would + + + align:start position:0% +letters uh and it it it would you would +still have a subsequence corresponding + + align:start position:0% +still have a subsequence corresponding + + + align:start position:0% +still have a subsequence corresponding +to that don't have to be contiguous and + + align:start position:0% +to that don't have to be contiguous and + + + align:start position:0% +to that don't have to be contiguous and +then uh we'll raise the stakes a little + + align:start position:0% +then uh we'll raise the stakes a little + + + align:start position:0% +then uh we'll raise the stakes a little +bit so each of these uh problems uh gets + + align:start position:0% +bit so each of these uh problems uh gets + + + align:start position:0% +bit so each of these uh problems uh gets +progressively more complicated more + + align:start position:0% +progressively more complicated more + + + align:start position:0% +progressively more complicated more +sophisticated and you'll probably see uh + + align:start position:0% +sophisticated and you'll probably see uh + + + align:start position:0% +sophisticated and you'll probably see uh +uh problems here at least alternating + + align:start position:0% +uh problems here at least alternating + + + align:start position:0% +uh problems here at least alternating +coin game that are + + align:start position:0% +coin game that are + + + align:start position:0% +coin game that are +beyond6 uh in the sense that it wasn't + + align:start position:0% +beyond6 uh in the sense that it wasn't + + + align:start position:0% +beyond6 uh in the sense that it wasn't +covered those kinds of Notions weren't + + align:start position:0% +covered those kinds of Notions weren't + + + align:start position:0% +covered those kinds of Notions weren't +covered + + align:start position:0% +covered + + + align:start position:0% +covered +in6 so just in terms of review I wrote + + align:start position:0% +in6 so just in terms of review I wrote + + + align:start position:0% +in6 so just in terms of review I wrote +this up here because I don't want to + + align:start position:0% +this up here because I don't want to + + + align:start position:0% +this up here because I don't want to +spend a whole lot of time on it uh this + + align:start position:0% +spend a whole lot of time on it uh this + + + align:start position:0% +spend a whole lot of time on it uh this +is something that uh you should have + + align:start position:0% +is something that uh you should have + + + align:start position:0% +is something that uh you should have +some familiarity with uh by + + align:start position:0% +some familiarity with uh by + + + align:start position:0% +some familiarity with uh by +I from the recitation for example that + + align:start position:0% +I from the recitation for example that + + + align:start position:0% +I from the recitation for example that +you had on Friday and from dou six + + align:start position:0% +you had on Friday and from dou six + + + align:start position:0% +you had on Friday and from dou six +dynamic programming is this wonderful + + align:start position:0% +dynamic programming is this wonderful + + + align:start position:0% +dynamic programming is this wonderful +Hammer it's a an algorithmic technique + + align:start position:0% +Hammer it's a an algorithmic technique + + + align:start position:0% +Hammer it's a an algorithmic technique +that you can use to solve problems that + + align:start position:0% +that you can use to solve problems that + + + align:start position:0% +that you can use to solve problems that +you know look exponential in complexity + + align:start position:0% +you know look exponential in complexity + + + align:start position:0% +you know look exponential in complexity +but if you can find this Optimum + + align:start position:0% +but if you can find this Optimum + + + align:start position:0% +but if you can find this Optimum +substructure associated with the the + + align:start position:0% +substructure associated with the the + + + align:start position:0% +substructure associated with the the +problem and its connection to its sub + + align:start position:0% +problem and its connection to its sub + + + align:start position:0% +problem and its connection to its sub +problems and if you can characterize + + align:start position:0% +problems and if you can characterize + + + align:start position:0% +problems and if you can characterize +that then you can do a recursive + + align:start position:0% +that then you can do a recursive + + + align:start position:0% +that then you can do a recursive +decomposition of the problem where you + + align:start position:0% +decomposition of the problem where you + + + align:start position:0% +decomposition of the problem where you +show that you can construct + + align:start position:0% +show that you can construct + + + align:start position:0% +show that you can construct +the optimum solution from the sub + + align:start position:0% +the optimum solution from the sub + + + align:start position:0% +the optimum solution from the sub +problems and that's really the the key + + align:start position:0% +problems and that's really the the key + + + align:start position:0% +problems and that's really the the key +step really in dynamic programming is uh + + align:start position:0% +step really in dynamic programming is uh + + + align:start position:0% +step really in dynamic programming is uh +step two you know once you've made this + + align:start position:0% +step two you know once you've made this + + + align:start position:0% +step two you know once you've made this +characterization where you write this + + align:start position:0% +characterization where you write this + + + align:start position:0% +characterization where you write this +recurrence out that relates the optimal + + align:start position:0% +recurrence out that relates the optimal + + + align:start position:0% +recurrence out that relates the optimal +value of a bigger problem to the optimal + + align:start position:0% +value of a bigger problem to the optimal + + + align:start position:0% +value of a bigger problem to the optimal +values of sub problems and um you + + align:start position:0% +values of sub problems and um you + + + align:start position:0% +values of sub problems and um you +compute the value of the optimal + + align:start position:0% +compute the value of the optimal + + + align:start position:0% +compute the value of the optimal +solution uh through uh a recursive memo + + align:start position:0% +solution uh through uh a recursive memo + + + align:start position:0% +solution uh through uh a recursive memo +memorize or recursive + + align:start position:0% +memorize or recursive + + + align:start position:0% +memorize or recursive +memorization and uh that memorization is + + align:start position:0% +memorization and uh that memorization is + + + align:start position:0% +memorization and uh that memorization is +really what gives you the + + align:start position:0% +really what gives you the + + + align:start position:0% +really what gives you the +efficient algorithm because you don't + + align:start position:0% +efficient algorithm because you don't + + + align:start position:0% +efficient algorithm because you don't +repeat the solution of sub problems you + + align:start position:0% +repeat the solution of sub problems you + + + align:start position:0% +repeat the solution of sub problems you +can also do this in an iterative fashion + + align:start position:0% +can also do this in an iterative fashion + + + align:start position:0% +can also do this in an iterative fashion +essentially you're going to be Computing + + align:start position:0% +essentially you're going to be Computing + + + align:start position:0% +essentially you're going to be Computing +things bottom up U you might want to + + align:start position:0% +things bottom up U you might want to + + + align:start position:0% +things bottom up U you might want to +think about it as top down when you + + align:start position:0% +think about it as top down when you + + + align:start position:0% +think about it as top down when you +write your recurrence But ultimately + + align:start position:0% +write your recurrence But ultimately + + + align:start position:0% +write your recurrence But ultimately +when you actually execute the program + + align:start position:0% +when you actually execute the program + + + align:start position:0% +when you actually execute the program +you'll be Computing things bottom up and + + align:start position:0% +you'll be Computing things bottom up and + + + align:start position:0% +you'll be Computing things bottom up and +you'll be checking the memo table to see + + align:start position:0% +you'll be checking the memo table to see + + + align:start position:0% +you'll be checking the memo table to see +if you've actually solved this problem + + align:start position:0% +if you've actually solved this problem + + + align:start position:0% +if you've actually solved this problem +before and uh that would be the + + align:start position:0% +before and uh that would be the + + + align:start position:0% +before and uh that would be the +recursive memoi case which in some sense + + align:start position:0% +recursive memoi case which in some sense + + + align:start position:0% +recursive memoi case which in some sense +is a little bit easier to think about + + align:start position:0% +is a little bit easier to think about + + + align:start position:0% +is a little bit easier to think about +and translates directly from the + + align:start position:0% +and translates directly from the + + + align:start position:0% +and translates directly from the +recurrence uh but the other way to do it + + align:start position:0% +recurrence uh but the other way to do it + + + align:start position:0% +recurrence uh but the other way to do it +is to do it iteratively and uh we'll + + align:start position:0% +is to do it iteratively and uh we'll + + + align:start position:0% +is to do it iteratively and uh we'll +take a look for this first problem as to + + align:start position:0% +take a look for this first problem as to + + + align:start position:0% +take a look for this first problem as to +how you would do the two different ways + + align:start position:0% +how you would do the two different ways + + + align:start position:0% +how you would do the two different ways +um at least from a conceptual standpoint + + align:start position:0% +um at least from a conceptual standpoint + + + align:start position:0% +um at least from a conceptual standpoint +uh even though I might not write out the + + align:start position:0% +uh even though I might not write out the + + + align:start position:0% +uh even though I might not write out the +code of for each of those cases so a + + align:start position:0% +code of for each of those cases so a + + + align:start position:0% +code of for each of those cases so a +couple of choices here recurs in memo wi + + align:start position:0% +couple of choices here recurs in memo wi + + + align:start position:0% +couple of choices here recurs in memo wi +or um + + align:start position:0% +or um + + + align:start position:0% +or um +essentially do it tively and the smaller + + align:start position:0% +essentially do it tively and the smaller + + + align:start position:0% +essentially do it tively and the smaller +sub problems would have to get computed + + align:start position:0% +sub problems would have to get computed + + + align:start position:0% +sub problems would have to get computed +first in both uh approaches uh the one + + align:start position:0% +first in both uh approaches uh the one + + + align:start position:0% +first in both uh approaches uh the one +thing that uh sometimes we don't spend a + + align:start position:0% +thing that uh sometimes we don't spend a + + + align:start position:0% +thing that uh sometimes we don't spend a +whole lot of time on is this last step + + align:start position:0% +whole lot of time on is this last step + + + align:start position:0% +whole lot of time on is this last step +which is getting the exact solution so a + + align:start position:0% +which is getting the exact solution so a + + + align:start position:0% +which is getting the exact solution so a +lot of the time you stop with saying I + + align:start position:0% +lot of the time you stop with saying I + + + align:start position:0% +lot of the time you stop with saying I +can compute the value of the optim + + align:start position:0% +can compute the value of the optim + + + align:start position:0% +can compute the value of the optim +Optimum solution the value of in terms + + align:start position:0% +Optimum solution the value of in terms + + + align:start position:0% +Optimum solution the value of in terms +of the length of the longest pal + + align:start position:0% +of the length of the longest pal + + + align:start position:0% +of the length of the longest pal +sequence is seven or nine but what is + + align:start position:0% +sequence is seven or nine but what is + + + align:start position:0% +sequence is seven or nine but what is +that sequence or subsequence that + + align:start position:0% +that sequence or subsequence that + + + align:start position:0% +that sequence or subsequence that +requires some additional coding some + + align:start position:0% +requires some additional coding some + + + align:start position:0% +requires some additional coding some +additional uh accounting some uh uh the + + align:start position:0% +additional uh accounting some uh uh the + + + align:start position:0% +additional uh accounting some uh uh the +construction of this optimal solution + + align:start position:0% +construction of this optimal solution + + + align:start position:0% +construction of this optimal solution +typically requires some back tracing and + + align:start position:0% +typically requires some back tracing and + + + align:start position:0% +typically requires some back tracing and +some uh information to + + align:start position:0% +some uh information to + + + align:start position:0% +some uh information to +be keep kept track of during the + + align:start position:0% +be keep kept track of during the + + + align:start position:0% +be keep kept track of during the +recursion memoized step or during the + + align:start position:0% +recursion memoized step or during the + + + align:start position:0% +recursion memoized step or during the +iterative step right so that's something + + align:start position:0% +iterative step right so that's something + + + align:start position:0% +iterative step right so that's something +to keep in mind you're not quite done + + align:start position:0% +to keep in mind you're not quite done + + + align:start position:0% +to keep in mind you're not quite done +once you found the value of the optimum + + align:start position:0% +once you found the value of the optimum + + + align:start position:0% +once you found the value of the optimum +solution and more often than not you + + align:start position:0% +solution and more often than not you + + + align:start position:0% +solution and more often than not you +want the solution right so we'll talk + + align:start position:0% +want the solution right so we'll talk + + + align:start position:0% +want the solution right so we'll talk +about that as well a little bit but + + align:start position:0% +about that as well a little bit but + + + align:start position:0% +about that as well a little bit but +let's just dive in and uh look + + align:start position:0% +let's just dive in and uh look + + + align:start position:0% +let's just dive in and uh look +at this cute little + + align:start position:0% +at this cute little + + + align:start position:0% +at this cute little +problem of uh longest Palam dromic + + align:start position:0% +problem of uh longest Palam dromic + + + align:start position:0% +problem of uh longest Palam dromic +sequence + + align:start position:0% +sequence + + + align:start position:0% +sequence +and palindromes of course read the + + align:start position:0% +and palindromes of course read the + + + align:start position:0% +and palindromes of course read the +same front to back or back to front + + align:start position:0% +same front to back or back to front + + + align:start position:0% +same front to back or back to front +radar is a palindrome uh just as a + + align:start position:0% +radar is a palindrome uh just as a + + + align:start position:0% +radar is a palindrome uh just as a +trivial example a single letter is a + + align:start position:0% +trivial example a single letter is a + + + align:start position:0% +trivial example a single letter is a +palindrome U maybe I should have used u + + align:start position:0% +palindrome U maybe I should have used u + + + align:start position:0% +palindrome U maybe I should have used u +a since that's actually a word uh but uh + + align:start position:0% +a since that's actually a word uh but uh + + + align:start position:0% +a since that's actually a word uh but uh +you know here I got BB and that's not + + align:start position:0% +you know here I got BB and that's not + + + align:start position:0% +you know here I got BB and that's not +definitely not a word um at least not a + + align:start position:0% +definitely not a word um at least not a + + + align:start position:0% +definitely not a word um at least not a +word + + align:start position:0% +word + + + align:start position:0% +word +that acronym maybe um rder is a + + align:start position:0% +that acronym maybe um rder is a + + + align:start position:0% +that acronym maybe um rder is a +palindrome + + align:start position:0% +palindrome + + + align:start position:0% +palindrome +able was I I saw Elba right that's a + + align:start position:0% +able was I I saw Elba right that's a + + + align:start position:0% +able was I I saw Elba right that's a +palindrome and that's of course not a + + align:start position:0% +palindrome and that's of course not a + + + align:start position:0% +palindrome and that's of course not a +single word but it's a famous palindrome + + align:start position:0% +single word but it's a famous palindrome + + + align:start position:0% +single word but it's a famous palindrome +uh days of Napoleon uh but what we're + + align:start position:0% +uh days of Napoleon uh but what we're + + + align:start position:0% +uh days of Napoleon uh but what we're +trying to do here is uh given that we + + align:start position:0% +trying to do here is uh given that we + + + align:start position:0% +trying to do here is uh given that we +have uh this notion of a palindrome we'd + + align:start position:0% +have uh this notion of a palindrome we'd + + + align:start position:0% +have uh this notion of a palindrome we'd +like to discover palindromes + + align:start position:0% +like to discover palindromes + + + align:start position:0% +like to discover palindromes +inside longer words or longer sequences + + align:start position:0% +inside longer words or longer sequences + + + align:start position:0% +inside longer words or longer sequences +so what we have is a + + align:start position:0% +so what we have is a + + + align:start position:0% +so what we have is a +string and we'll call it + + align:start position:0% +string and we'll call it + + + align:start position:0% +string and we'll call it +X1 through n n greater than or equal to + + align:start position:0% +X1 through n n greater than or equal to + + + align:start position:0% +X1 through n n greater than or equal to +1 and we want to find the + + align:start position:0% +1 and we want to find the + + + align:start position:0% +1 and we want to find the +longest + + align:start position:0% + + + + align:start position:0% + +palindrome + + align:start position:0% +palindrome + + + align:start position:0% +palindrome +that is a + + align:start position:0% + + + + align:start position:0% + +subsequence and so here's an example to + + align:start position:0% +subsequence and so here's an example to + + + align:start position:0% +subsequence and so here's an example to +get you guys warmed up we'll have a + + align:start position:0% +get you guys warmed up we'll have a + + + align:start position:0% +get you guys warmed up we'll have a +couple of puzzles here in a + + align:start position:0% +couple of puzzles here in a + + + align:start position:0% +couple of puzzles here in a +second so character + + align:start position:0% +second so character + + + align:start position:0% +second so character +and you want to find the longest + + align:start position:0% +and you want to find the longest + + + align:start position:0% +and you want to find the longest +palindrome and so you go I'll pick C + + align:start position:0% +palindrome and so you go I'll pick C + + + align:start position:0% +palindrome and so you go I'll pick C +I'll skip H I'll pick a I'll pick R A + + align:start position:0% +I'll skip H I'll pick a I'll pick R A + + + align:start position:0% +I'll skip H I'll pick a I'll pick R A +and C + + align:start position:0% +and C + + + align:start position:0% +and C +and carak which I guess is not a word + + align:start position:0% +and carak which I guess is not a word + + + align:start position:0% +and carak which I guess is not a word +either but uh it's uh it's the + + align:start position:0% +either but uh it's uh it's the + + + align:start position:0% +either but uh it's uh it's the +longest palindrome that corresponds to a + + align:start position:0% +longest palindrome that corresponds to a + + + align:start position:0% +longest palindrome that corresponds to a +subsequence of character right so uh the + + align:start position:0% +subsequence of character right so uh the + + + align:start position:0% +subsequence of character right so uh the +game here as you can see is to pick the + + align:start position:0% +game here as you can see is to pick the + + + align:start position:0% +game here as you can see is to pick the +letters + + align:start position:0% +letters + + + align:start position:0% +letters +that I form the palindrome and drop the + + align:start position:0% +that I form the palindrome and drop the + + + align:start position:0% +that I form the palindrome and drop the +ones that don't okay and we're going to + + align:start position:0% +ones that don't okay and we're going to + + + align:start position:0% +ones that don't okay and we're going to +have to use dynamic programming uh to do + + align:start position:0% +have to use dynamic programming uh to do + + + align:start position:0% +have to use dynamic programming uh to do +this uh the + + align:start position:0% +this uh the + + + align:start position:0% +this uh the +answer will be greater than or one in + + align:start position:0% +answer will be greater than or one in + + + align:start position:0% +answer will be greater than or one in +length because we've defined a single + + align:start position:0% +length because we've defined a single + + + align:start position:0% +length because we've defined a single +letter as a palindrome right so it has + + align:start position:0% +letter as a palindrome right so it has + + + align:start position:0% +letter as a palindrome right so it has +to be if you have one letter in the + + align:start position:0% +to be if you have one letter in the + + + align:start position:0% +to be if you have one letter in the +input well you just pick that letter but + + align:start position:0% +input well you just pick that letter but + + + align:start position:0% +input well you just pick that letter but +regardless of how many letters you have + + align:start position:0% +regardless of how many letters you have + + + align:start position:0% +regardless of how many letters you have +on the input greater than equal to one + + align:start position:0% +on the input greater than equal to one + + + align:start position:0% +on the input greater than equal to one +you know that you're going to get at + + align:start position:0% +you know that you're going to get at + + + align:start position:0% +you know that you're going to get at +least a a onlet palindrome at the + + align:start position:0% +least a a onlet palindrome at the + + + align:start position:0% +least a a onlet palindrome at the +output uh so here we + + align:start position:0% + + + + align:start position:0% + +go let's say I have under and this is + + align:start position:0% +go let's say I have under and this is + + + align:start position:0% +go let's say I have under and this is +thanks to Eric + + align:start position:0% +thanks to Eric + + + align:start position:0% +thanks to Eric +here got a couple of nice words + + align:start position:0% +here got a couple of nice words + + + align:start position:0% +here got a couple of nice words +underqualified + + align:start position:0% +underqualified + + + align:start position:0% +underqualified +the person who gets me the longest + + align:start position:0% +the person who gets me the longest + + + align:start position:0% +the person who gets me the longest +palindrome Vin of Frisbee and if you + + align:start position:0% +palindrome Vin of Frisbee and if you + + + align:start position:0% +palindrome Vin of Frisbee and if you +want to code dynamic programming the + + align:start position:0% +want to code dynamic programming the + + + align:start position:0% +want to code dynamic programming the +next two minutes and run it on your + + align:start position:0% +next two minutes and run it on your + + + align:start position:0% +next two minutes and run it on your +laptops that's perfectly fine with me + + align:start position:0% +laptops that's perfectly fine with me + + + align:start position:0% +laptops that's perfectly fine with me +that's not cheating okay so + + align:start position:0% +that's not cheating okay so + + + align:start position:0% +that's not cheating okay so +underqualified + + align:start position:0% +underqualified + + + align:start position:0% +underqualified +so U is a palr so we got that right so + + align:start position:0% +so U is a palr so we got that right so + + + align:start position:0% +so U is a palr so we got that right so +one letter for + + align:start position:0% +one letter for + + + align:start position:0% +one letter for +sure what else what's the longest + + align:start position:0% +sure what else what's the longest + + + align:start position:0% +sure what else what's the longest +palindrome shout it out go go ahead + + align:start position:0% +palindrome shout it out go go ahead + + + align:start position:0% +palindrome shout it out go go ahead +Shout It + + align:start position:0% +Shout It + + + align:start position:0% +Shout It +Out Dei well that was quick deified + + align:start position:0% +Out Dei well that was quick deified + + + align:start position:0% +Out Dei well that was quick deified +that's right + + align:start position:0% +that's right + + + align:start position:0% +that's right +so um + + align:start position:0% +so um + + + align:start position:0% +so um +right well defi to make is is to make + + align:start position:0% +right well defi to make is is to make + + + align:start position:0% +right well defi to make is is to make +somebody u a a Dy so uh that was you + + align:start position:0% +somebody u a a Dy so uh that was you + + + align:start position:0% +somebody u a a Dy so uh that was you +couple couple of you + + align:start position:0% +couple couple of you + + + align:start position:0% +couple couple of you +guys uh do you have a frisbe yet all + + align:start position:0% + + + + align:start position:0% + +right all right this is a little bit + + align:start position:0% +right all right this is a little bit + + + align:start position:0% +right all right this is a little bit +more difficult I tried this on my on my + + align:start position:0% +more difficult I tried this on my on my + + + align:start position:0% +more difficult I tried this on my on my +daughter yesterday so I know it's a + + align:start position:0% +daughter yesterday so I know it's a + + + align:start position:0% +daughter yesterday so I know it's a +little more difficult + + align:start position:0% +little more difficult + + + align:start position:0% +little more difficult +right + + align:start position:0% +right + + + align:start position:0% +right +turbo ventilator + + align:start position:0% + + + + align:start position:0% + +right we'll call that a + + align:start position:0% +right we'll call that a + + + align:start position:0% +right we'll call that a +word right turbo ventilator right yell + + align:start position:0% +word right turbo ventilator right yell + + + align:start position:0% +word right turbo ventilator right yell +it + + align:start position:0% + + + + align:start position:0% + +out sorry rotor okay well that's five + + align:start position:0% +out sorry rotor okay well that's five + + + align:start position:0% +out sorry rotor okay well that's five +can anybody beat that + + align:start position:0% +can anybody beat that + + + align:start position:0% +can anybody beat that +Rotator so Rotator Rotator right so r o + + align:start position:0% +Rotator so Rotator Rotator right so r o + + + align:start position:0% +Rotator so Rotator Rotator right so r o +t a t o r + + align:start position:0% +t a t o r + + + align:start position:0% +t a t o r +Rotator all right + + align:start position:0% + + + + align:start position:0% + +who is the + + align:start position:0% +who is the + + + align:start position:0% +who is the +Rotator all right could you you already + + align:start position:0% +Rotator all right could you you already + + + align:start position:0% +Rotator all right could you you already +have one I I want to throw this one + + align:start position:0% +have one I I want to throw this one + + + align:start position:0% +have one I I want to throw this one +right um good practice with the quiz + + align:start position:0% +right um good practice with the quiz + + + align:start position:0% +right um good practice with the quiz +guys good practice with the quiz no no + + align:start position:0% +guys good practice with the quiz no no + + + align:start position:0% +guys good practice with the quiz no no +no these quiz jokes never go over well + + align:start position:0% +no these quiz jokes never go over well + + + align:start position:0% +no these quiz jokes never go over well +you know I've been teaching for 27 years + + align:start position:0% +you know I've been teaching for 27 years + + + align:start position:0% +you know I've been teaching for 27 years +and I still haven't learned that you + + align:start position:0% +and I still haven't learned that you + + + align:start position:0% +and I still haven't learned that you +don't joke about + + align:start position:0% +don't joke about + + + align:start position:0% +don't joke about +exams but I so nothing like this on the + + align:start position:0% +exams but I so nothing like this on the + + + align:start position:0% +exams but I so nothing like this on the +quiz I don't want you studying the + + align:start position:0% +quiz I don't want you studying the + + + align:start position:0% +quiz I don't want you studying the +thesaurus as opposed to the textbook for + + align:start position:0% +thesaurus as opposed to the textbook for + + + align:start position:0% +thesaurus as opposed to the textbook for +the for the next few hours okay nothing + + align:start position:0% +the for the next few hours okay nothing + + + align:start position:0% +the for the next few hours okay nothing +like this on the quiz all right um those + + align:start position:0% +like this on the quiz all right um those + + + align:start position:0% +like this on the quiz all right um those +of you who are missing + + align:start position:0% +of you who are missing + + + align:start position:0% +of you who are missing +python who loves 66 and python uh let's + + align:start position:0% +python who loves 66 and python uh let's + + + align:start position:0% +python who loves 66 and python uh let's +let's talk about uh uh how you would + + align:start position:0% +let's talk about uh uh how you would + + + align:start position:0% +let's talk about uh uh how you would +actually solve this using dynamic + + align:start position:0% +actually solve this using dynamic + + + align:start position:0% +actually solve this using dynamic +programming uh and so what we want is Li + + align:start position:0% +programming uh and so what we want is Li + + + align:start position:0% +programming uh and so what we want is Li +J which is the length + + align:start position:0% +J which is the length + + + align:start position:0% +J which is the length +of the + + align:start position:0% + + + + align:start position:0% + +longest palindromic uh + + align:start position:0% + + + + align:start position:0% + +subsequence for XI + + align:start position:0% +subsequence for XI + + + align:start position:0% +subsequence for XI +J and we're going to have I less than or + + align:start position:0% +J and we're going to have I less than or + + + align:start position:0% +J and we're going to have I less than or +equal to + + align:start position:0% + + + + align:start position:0% + +J so so that's essentially what we'd + + align:start position:0% +J so so that's essentially what we'd + + + align:start position:0% +J so so that's essentially what we'd +like to uh compute and essentially when + + align:start position:0% +like to uh compute and essentially when + + + align:start position:0% +like to uh compute and essentially when +I've set this + + align:start position:0% +I've set this + + + align:start position:0% +I've set this +here I when I have Li J I have + + align:start position:0% +here I when I have Li J I have + + + align:start position:0% +here I when I have Li J I have +decomposed the overall problem into sub + + align:start position:0% +decomposed the overall problem into sub + + + align:start position:0% +decomposed the overall problem into sub +problems and it's kind of Fairly obvious + + align:start position:0% +problems and it's kind of Fairly obvious + + + align:start position:0% +problems and it's kind of Fairly obvious +in this case because I'm going to have + + align:start position:0% +in this case because I'm going to have + + + align:start position:0% +in this case because I'm going to have +to go in order right I mean that's the + + align:start position:0% +to go in order right I mean that's the + + + align:start position:0% +to go in order right I mean that's the +constraint a subsequence does maintain + + align:start position:0% +constraint a subsequence does maintain + + + align:start position:0% +constraint a subsequence does maintain +the ordering constraint it's not like I + + align:start position:0% +the ordering constraint it's not like I + + + align:start position:0% +the ordering constraint it's not like I +can invert these letters right that + + align:start position:0% +can invert these letters right that + + + align:start position:0% +can invert these letters right that +would be a different problem if I + + align:start position:0% +would be a different problem if I + + + align:start position:0% +would be a different problem if I +allowed you to do that so um I'm going + + align:start position:0% +allowed you to do that so um I'm going + + + align:start position:0% +allowed you to do that so um I'm going +to start somewhere and I'm going to end + + align:start position:0% +to start somewhere and I'm going to end + + + align:start position:0% +to start somewhere and I'm going to end +somewhere and I want to have a non-null + + align:start position:0% +somewhere and I want to have a non-null + + + align:start position:0% +somewhere and I want to have a non-null +subsequence so I'm going to have I less + + align:start position:0% +subsequence so I'm going to have I less + + + align:start position:0% +subsequence so I'm going to have I less +than or equal to J I'm good with I being + + align:start position:0% +than or equal to J I'm good with I being + + + align:start position:0% +than or equal to J I'm good with I being +equal to J because I still have one + + align:start position:0% +equal to J because I still have one + + + align:start position:0% +equal to J because I still have one +letter and well that happens to be a + + align:start position:0% +letter and well that happens to be a + + + align:start position:0% +letter and well that happens to be a +palindrome and it'll have a length of + + align:start position:0% +palindrome and it'll have a length of + + + align:start position:0% +palindrome and it'll have a length of +one right so that's my li + + align:start position:0% +one right so that's my li + + + align:start position:0% +one right so that's my li +J and what I want to do is uh Define a a + + align:start position:0% +J and what I want to do is uh Define a a + + + align:start position:0% +J and what I want to do is uh Define a a +recursive + + align:start position:0% + + + + align:start position:0% + +algorithm that computes Li right so U + + align:start position:0% +algorithm that computes Li right so U + + + align:start position:0% +algorithm that computes Li right so U +we'll just try and figure out what the + + align:start position:0% +we'll just try and figure out what the + + + align:start position:0% +we'll just try and figure out what the +recurrence looks like and then we can + + align:start position:0% +recurrence looks like and then we can + + + align:start position:0% +recurrence looks like and then we can +talk about uh memorization or iteration + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +if I equals equals + + align:start position:0% +if I equals equals + + + align:start position:0% +if I equals equals +J then I'm going to return one because I + + align:start position:0% +J then I'm going to return one because I + + + align:start position:0% +J then I'm going to return one because I +know that that's a palindrome right by + + align:start position:0% +know that that's a palindrome right by + + + align:start position:0% +know that that's a palindrome right by +default so that's + + align:start position:0% +default so that's + + + align:start position:0% +default so that's +easy + + align:start position:0% +easy + + + align:start position:0% +easy +and um what do you think the next check + + align:start position:0% +and um what do you think the next check + + + align:start position:0% +and um what do you think the next check +should be if if I look at this x + + align:start position:0% +should be if if I look at this x + + + align:start position:0% +should be if if I look at this x +sequence and I've have I as the starting + + align:start position:0% +sequence and I've have I as the starting + + + align:start position:0% +sequence and I've have I as the starting +point in J as the next uh Point what do + + align:start position:0% +point in J as the next uh Point what do + + + align:start position:0% +point in J as the next uh Point what do +you think the next check is going to be + + align:start position:0% +you think the next check is going to be + + + align:start position:0% +you think the next check is going to be +once I have if I is not equal to + + align:start position:0% + + + + align:start position:0% + +J uh sorry what was that again if x + + align:start position:0% +J uh sorry what was that again if x + + + align:start position:0% +J uh sorry what was that again if x +IAL beautiful you're just checking to + + align:start position:0% +IAL beautiful you're just checking to + + + align:start position:0% +IAL beautiful you're just checking to +see uh you're you're just checking to + + align:start position:0% +see uh you're you're just checking to + + + align:start position:0% +see uh you're you're just checking to +see whether uh uh the two end points are + + align:start position:0% +see whether uh uh the two end points are + + + align:start position:0% +see whether uh uh the two end points are +equal or not because if they're equal uh + + align:start position:0% +equal or not because if they're equal uh + + + align:start position:0% +equal or not because if they're equal uh +then you can uh essentially uh grab + + align:start position:0% +then you can uh essentially uh grab + + + align:start position:0% +then you can uh essentially uh grab +those letters and uh say that you're + + align:start position:0% +those letters and uh say that you're + + + align:start position:0% +those letters and uh say that you're +going to be looking at a + + align:start position:0% +going to be looking at a + + + align:start position:0% +going to be looking at a +smaller + + align:start position:0% +smaller + + + align:start position:0% +smaller +subsequence that uh is going to uh get + + align:start position:0% +subsequence that uh is going to uh get + + + align:start position:0% +subsequence that uh is going to uh get +you a palindrome and you're going to be + + align:start position:0% +you a palindrome and you're going to be + + + align:start position:0% +you a palindrome and you're going to be +able to add these two letters that are + + align:start position:0% +able to add these two letters that are + + + align:start position:0% +able to add these two letters that are +equal on either side of the computed + + align:start position:0% +equal on either side of the computed + + + align:start position:0% +equal on either side of the computed +palindrome from the subsequence right so + + align:start position:0% +palindrome from the subsequence right so + + + align:start position:0% +palindrome from the subsequence right so +if x of + + align:start position:0% +if x of + + + align:start position:0% +if x of +I um equals equals x of + + align:start position:0% +I um equals equals x of + + + align:start position:0% +I um equals equals x of +J then uh I'm going + + align:start position:0% +J then uh I'm going + + + align:start position:0% +J then uh I'm going +to say if + + align:start position:0% +to say if + + + align:start position:0% +to say if +I + 1al equal J I'm going to go ahead + + align:start position:0% +I + 1al equal J I'm going to go ahead + + + align:start position:0% +I + 1al equal J I'm going to go ahead +and return + + align:start position:0% +and return + + + align:start position:0% +and return +two because uh at that point I'm I'm + + align:start position:0% +two because uh at that point I'm I'm + + + align:start position:0% +two because uh at that point I'm I'm +done there's no nothing else to do um + + align:start position:0% + + + + align:start position:0% + +else I'm going to return + + align:start position:0% +else I'm going to return + + + align:start position:0% +else I'm going to return +2+ L of I + 1 Jus one right so I'm going + + align:start position:0% +2+ L of I + 1 Jus one right so I'm going + + + align:start position:0% +2+ L of I + 1 Jus one right so I'm going +to look inside and got these two letters + + align:start position:0% +to look inside and got these two letters + + + align:start position:0% +to look inside and got these two letters +on either side that are equal so I can + + align:start position:0% +on either side that are equal so I can + + + align:start position:0% +on either side that are equal so I can +always uh prepend to the palindrome I + + align:start position:0% +always uh prepend to the palindrome I + + + align:start position:0% +always uh prepend to the palindrome I +got from here the letter and then a pen + + align:start position:0% +got from here the letter and then a pen + + + align:start position:0% +got from here the letter and then a pen +the same letter and I got two plus + + align:start position:0% +the same letter and I got two plus + + + align:start position:0% +the same letter and I got two plus +whatever value I got from this quantity + + align:start position:0% +whatever value I got from this quantity + + + align:start position:0% +whatever value I got from this quantity +here all right so so so far uh it's uh + + align:start position:0% +here all right so so so far uh it's uh + + + align:start position:0% +here all right so so so far uh it's uh +not really particularly interesting from + + align:start position:0% +not really particularly interesting from + + + align:start position:0% +not really particularly interesting from +a standpoint of constructing the optimum + + align:start position:0% +a standpoint of constructing the optimum + + + align:start position:0% +a standpoint of constructing the optimum +solution but this last line that we have + + align:start position:0% +solution but this last line that we have + + + align:start position:0% +solution but this last line that we have +here where we have the case that the two + + align:start position:0% +here where we have the case that the two + + + align:start position:0% +here where we have the case that the two +letters are not equal is the most + + align:start position:0% +letters are not equal is the most + + + align:start position:0% +letters are not equal is the most +interesting line of code that's the most + + align:start position:0% +interesting line of code that's the most + + + align:start position:0% +interesting line of code that's the most +interesting aspect of this algorithm + + align:start position:0% +interesting aspect of this algorithm + + + align:start position:0% +interesting aspect of this algorithm +right so someone want to tell me what + + align:start position:0% +right so someone want to tell me what + + + align:start position:0% +right so someone want to tell me what +this line is going to be out here yeah + + align:start position:0% +this line is going to be out here yeah + + + align:start position:0% +this line is going to be out here yeah +go + + align:start position:0% + + + + align:start position:0% + +ahead beautiful that's exactly right so + + align:start position:0% +ahead beautiful that's exactly right so + + + align:start position:0% +ahead beautiful that's exactly right so +what you're going to do is you're going + + align:start position:0% +what you're going to do is you're going + + + align:start position:0% +what you're going to do is you're going +to say I need to look at two different + + align:start position:0% +to say I need to look at two different + + + align:start position:0% +to say I need to look at two different +sub problems and I need to evaluate both + + align:start position:0% +sub problems and I need to evaluate both + + + align:start position:0% +sub problems and I need to evaluate both +of the sub + + align:start position:0% +of the sub + + + align:start position:0% +of the sub +problems uh and the first sub problem is + + align:start position:0% +problems uh and the first sub problem is + + + align:start position:0% +problems uh and the first sub problem is +I'm going to since these two letters are + + align:start position:0% +I'm going to since these two letters are + + + align:start position:0% +I'm going to since these two letters are +different I'm going to have to drop one + + align:start position:0% +different I'm going to have to drop one + + + align:start position:0% +different I'm going to have to drop one +of them okay and I'm going to look + + align:start position:0% +of them okay and I'm going to look + + + align:start position:0% +of them okay and I'm going to look +inside I'm going to say I in this case + + align:start position:0% +inside I'm going to say I in this case + + + align:start position:0% +inside I'm going to say I in this case +I'm going to drop the i letter and I'm + + align:start position:0% +I'm going to drop the i letter and I'm + + + align:start position:0% +I'm going to drop the i letter and I'm +going to get l i + 1 J and in the second + + align:start position:0% +going to get l i + 1 J and in the second + + + align:start position:0% +going to get l i + 1 J and in the second +case I'm going to drop the jth letter + + align:start position:0% +case I'm going to drop the jth letter + + + align:start position:0% +case I'm going to drop the jth letter +and I'm going to get i j minus + + align:start position:0% +and I'm going to get i j minus + + + align:start position:0% +and I'm going to get i j minus +one and that's it so it's a a Max and + + align:start position:0% +one and that's it so it's a a Max and + + + align:start position:0% +one and that's it so it's a a Max and +there's nothing that's being added here + + align:start position:0% +there's nothing that's being added here + + + align:start position:0% +there's nothing that's being added here +because those two letters one of them + + align:start position:0% +because those two letters one of them + + + align:start position:0% +because those two letters one of them +had to get + + align:start position:0% +had to get + + + align:start position:0% +had to get +dropped they weren't equal so one of + + align:start position:0% +dropped they weren't equal so one of + + + align:start position:0% +dropped they weren't equal so one of +them had to get dropped so you're not + + align:start position:0% +them had to get dropped so you're not + + + align:start position:0% +them had to get dropped so you're not +adding anything to this right so uh so + + align:start position:0% +adding anything to this right so uh so + + + align:start position:0% +adding anything to this right so uh so +that's good and at this point you're + + align:start position:0% +that's good and at this point you're + + + align:start position:0% +that's good and at this point you're +kind of done right + + align:start position:0% +kind of done right + + + align:start position:0% +kind of done right +um whoops oh nice catch but you did drop + + align:start position:0% + + + + align:start position:0% + +something uh all right so uh the the + + align:start position:0% +something uh all right so uh the the + + + align:start position:0% +something uh all right so uh the the +thing that we've done here is gotten to + + align:start position:0% +thing that we've done here is gotten to + + + align:start position:0% +thing that we've done here is gotten to +U step three right so just to be clear + + align:start position:0% +U step three right so just to be clear + + + align:start position:0% +U step three right so just to be clear +we're not done done in terms of this + + align:start position:0% +we're not done done in terms of this + + + align:start position:0% +we're not done done in terms of this +chart here because uh we don't have the + + align:start position:0% +chart here because uh we don't have the + + + align:start position:0% +chart here because uh we don't have the +code there that corresponds + + align:start position:0% +code there that corresponds + + + align:start position:0% +code there that corresponds +to actually + + align:start position:0% +to actually + + + align:start position:0% +to actually +Computing uh the sequence right so it's + + align:start position:0% +Computing uh the sequence right so it's + + + align:start position:0% +Computing uh the sequence right so it's +not that hard I'm I'm not going to go + + align:start position:0% +not that hard I'm I'm not going to go + + + align:start position:0% +not that hard I'm I'm not going to go +over uh the code here I I'll you can + + align:start position:0% +over uh the code here I I'll you can + + + align:start position:0% +over uh the code here I I'll you can +certainly U look at it in the notes uh + + align:start position:0% +certainly U look at it in the notes uh + + + align:start position:0% +certainly U look at it in the notes uh +but uh you need a little bit of uh + + align:start position:0% +but uh you need a little bit of uh + + + align:start position:0% +but uh you need a little bit of uh +tracing backwards in this uh recursion + + align:start position:0% +tracing backwards in this uh recursion + + + align:start position:0% +tracing backwards in this uh recursion +to actually compute things what is the + + align:start position:0% +to actually compute things what is the + + + align:start position:0% +to actually compute things what is the +complexity of what I wrote up there + + align:start position:0% +complexity of what I wrote up there + + + align:start position:0% +complexity of what I wrote up there +though yeah s Theta n Square do people + + align:start position:0% +though yeah s Theta n Square do people + + + align:start position:0% +though yeah s Theta n Square do people +agree that the complexity is Theta n + + align:start position:0% +agree that the complexity is Theta n + + + align:start position:0% +agree that the complexity is Theta n +square or is this gentleman an + + align:start position:0% + + + + align:start position:0% + +optimist is this is the complexity Theta + + align:start position:0% +optimist is this is the complexity Theta + + + align:start position:0% +optimist is this is the complexity Theta +n Square tell me why the complexity is + + align:start position:0% +n Square tell me why the complexity is + + + align:start position:0% +n Square tell me why the complexity is +Theta n Square because each sub problem + + align:start position:0% +Theta n Square because each sub problem + + + align:start position:0% +Theta n Square because each sub problem +is that that code right there + + align:start position:0% + + + + align:start position:0% + +absolutely but if you actually + + align:start position:0% +absolutely but if you actually + + + align:start position:0% +absolutely but if you actually +implemented this code and you ran it and + + align:start position:0% +implemented this code and you ran it and + + + align:start position:0% +implemented this code and you ran it and +N was a was a was 100 how long would you + + align:start position:0% +N was a was a was 100 how long would you + + + align:start position:0% +N was a was a was 100 how long would you +wait for this code to + + align:start position:0% + + + + align:start position:0% + +complete look at it what's + + align:start position:0% +complete look at it what's + + + align:start position:0% +complete look at it what's +missing the cash exactly well you fixed + + align:start position:0% +missing the cash exactly well you fixed + + + align:start position:0% +missing the cash exactly well you fixed +U your own little error there it was a + + align:start position:0% +U your own little error there it was a + + + align:start position:0% +U your own little error there it was a +trick question okay so there's no + + align:start position:0% +trick question okay so there's no + + + align:start position:0% +trick question okay so there's no +recursion I'm sorry there's recursion + + align:start position:0% +recursion I'm sorry there's recursion + + + align:start position:0% +recursion I'm sorry there's recursion +here but no memorization right so this + + align:start position:0% +here but no memorization right so this + + + align:start position:0% +here but no memorization right so this +is exponential complexity right you will + + align:start position:0% +is exponential complexity right you will + + + align:start position:0% +is exponential complexity right you will +recur in fact the recurrence for that is + + align:start position:0% +recur in fact the recurrence for that is + + + align:start position:0% +recur in fact the recurrence for that is +something like T of n equal 1 if n equal + + align:start position:0% +something like T of n equal 1 if n equal + + + align:start position:0% +something like T of n equal 1 if n equal +1 and 2 T nus 1 if n greater than 1 and + + align:start position:0% +1 and 2 T nus 1 if n greater than 1 and + + + align:start position:0% +1 and 2 T nus 1 if n greater than 1 and +this would be 2 to n minus1 in + + align:start position:0% +this would be 2 to n minus1 in + + + align:start position:0% +this would be 2 to n minus1 in +complexity right now there's a single + + align:start position:0% +complexity right now there's a single + + + align:start position:0% +complexity right now there's a single +line of code and you all know this that + + align:start position:0% +line of code and you all know this that + + + align:start position:0% +line of code and you all know this that +would fix this right and that single + + align:start position:0% +would fix this right and that single + + + align:start position:0% +would fix this right and that single +line of code is simply something that + + align:start position:0% +line of code is simply something that + + + align:start position:0% +line of code is simply something that +says right + + align:start position:0% +says right + + + align:start position:0% +says right +here + + align:start position:0% +here + + + align:start position:0% +here +look at the LI J and I'm writing this + + align:start position:0% +look at the LI J and I'm writing this + + + align:start position:0% +look at the LI J and I'm writing this +differently I'm I'm I I'm calling this + + align:start position:0% +differently I'm I'm I I'm calling this + + + align:start position:0% +differently I'm I'm I I'm calling this +now a 2d array right so that's why I + + align:start position:0% +now a 2d array right so that's why I + + + align:start position:0% +now a 2d array right so that's why I +have the Open brackets and closed + + align:start position:0% +have the Open brackets and closed + + + align:start position:0% +have the Open brackets and closed +brackets so I'm overloading L here but + + align:start position:0% +brackets so I'm overloading L here but + + + align:start position:0% +brackets so I'm overloading L here but +it's a 2d array that is going to + + align:start position:0% +it's a 2d array that is going to + + + align:start position:0% +it's a 2d array that is going to +essentially be a cache for uh the sub + + align:start position:0% +essentially be a cache for uh the sub + + + align:start position:0% +essentially be a cache for uh the sub +problem solution values okay and then if + + align:start position:0% +problem solution values okay and then if + + + align:start position:0% +problem solution values okay and then if +you want to do the the back tracing to + + align:start position:0% +you want to do the the back tracing to + + + align:start position:0% +you want to do the the back tracing to +actually compute the solution you can + + align:start position:0% +actually compute the solution you can + + + align:start position:0% +actually compute the solution you can +certainly have that as an additional + + align:start position:0% +certainly have that as an additional + + + align:start position:0% +certainly have that as an additional +record that's uh connected to this very + + align:start position:0% +record that's uh connected to this very + + + align:start position:0% +record that's uh connected to this very +same value but that's uh implementation + + align:start position:0% +same value but that's uh implementation + + + align:start position:0% +same value but that's uh implementation +and we won't really go there so look at + + align:start position:0% +and we won't really go there so look at + + + align:start position:0% +and we won't really go there so look at +Li and don't + + align:start position:0% + + + + align:start position:0% + +recurse if Li already computed + + align:start position:0% + + + + align:start position:0% + +okay so that's important to remember + + align:start position:0% +okay so that's important to remember + + + align:start position:0% +okay so that's important to remember +right now if you actually put that uh + + align:start position:0% +right now if you actually put that uh + + + align:start position:0% +right now if you actually put that uh +the cache look up hash table look up + + align:start position:0% +the cache look up hash table look up + + + align:start position:0% +the cache look up hash table look up +array look up what whatever you want to + + align:start position:0% +array look up what whatever you want to + + + align:start position:0% +array look up what whatever you want to +call it out there then what you said is + + align:start position:0% +call it out there then what you said is + + + align:start position:0% +call it out there then what you said is +exactly correct right so our um our uh + + align:start position:0% +exactly correct right so our um our uh + + + align:start position:0% +exactly correct right so our um our uh +formula for computing the complexity of + + align:start position:0% +formula for computing the complexity of + + + align:start position:0% +formula for computing the complexity of +a DP that you've seen a bunch of times + + align:start position:0% +a DP that you've seen a bunch of times + + + align:start position:0% +a DP that you've seen a bunch of times +and I mentioned in the very first + + align:start position:0% +and I mentioned in the very first + + + align:start position:0% +and I mentioned in the very first +lecture as well is number of sub + + align:start position:0% + + + + align:start position:0% + +problems + + align:start position:0% +problems + + + align:start position:0% +problems +times + + align:start position:0% +times + + + align:start position:0% +times +time to + + align:start position:0% +time to + + + align:start position:0% +time to +solve each sub + + align:start position:0% +solve each sub + + + align:start position:0% +solve each sub +problem + + align:start position:0% +problem + + + align:start position:0% +problem +assuming are + + align:start position:0% + + + + align:start position:0% + +given that smaller + + align:start position:0% + + + + align:start position:0% + +ones are solved or a look is order one + + align:start position:0% +ones are solved or a look is order one + + + align:start position:0% +ones are solved or a look is order one +so look + + align:start position:0% + + + + align:start position:0% + +up now you could say the hash table look + + align:start position:0% +up now you could say the hash table look + + + align:start position:0% +up now you could say the hash table look +up is order one on average etc etc so um + + align:start position:0% +up is order one on average etc etc so um + + + align:start position:0% +up is order one on average etc etc so um +what actually happens in the worst case + + align:start position:0% +what actually happens in the worst case + + + align:start position:0% +what actually happens in the worst case +in this particular case and in most DPS + + align:start position:0% +in this particular case and in most DPS + + + align:start position:0% +in this particular case and in most DPS +uh you can uh do things like uh perfect + + align:start position:0% +uh you can uh do things like uh perfect + + + align:start position:0% +uh you can uh do things like uh perfect +hashing or something that's even simpler + + align:start position:0% +hashing or something that's even simpler + + + align:start position:0% +hashing or something that's even simpler +in this case it's just a 2d array + + align:start position:0% +in this case it's just a 2d array + + + align:start position:0% +in this case it's just a 2d array +there's not going to be any collisions + + align:start position:0% +there's not going to be any collisions + + + align:start position:0% +there's not going to be any collisions +if you just use I andj as the indices to + + align:start position:0% +if you just use I andj as the indices to + + + align:start position:0% +if you just use I andj as the indices to +the array so you will definitely get a + + align:start position:0% +the array so you will definitely get a + + + align:start position:0% +the array so you will definitely get a +an order one look up uh in in this case + + align:start position:0% +an order one look up uh in in this case + + + align:start position:0% +an order one look up uh in in this case +and most problems we look at uh in 046 + + align:start position:0% +and most problems we look at uh in 046 + + + align:start position:0% +and most problems we look at uh in 046 +so if you just do that computation which + + align:start position:0% +so if you just do that computation which + + + align:start position:0% +so if you just do that computation which +uh my friend over here just described + + align:start position:0% +uh my friend over here just described + + + align:start position:0% +uh my friend over here just described +you do get your Theta n Square because + + align:start position:0% +you do get your Theta n Square because + + + align:start position:0% +you do get your Theta n Square because +you have Theta n Square sub problems and + + align:start position:0% +you have Theta n Square sub problems and + + + align:start position:0% +you have Theta n Square sub problems and +uh um + + align:start position:0% +uh um + + + align:start position:0% +uh um +uh time to solve each sub problem + + align:start position:0% +uh time to solve each sub problem + + + align:start position:0% +uh time to solve each sub problem +given that the smaller ones are solved + + align:start position:0% +given that the smaller ones are solved + + + align:start position:0% +given that the smaller ones are solved +um is uh is is simply going to be a + + align:start position:0% +um is uh is is simply going to be a + + + align:start position:0% +um is uh is is simply going to be a +computation of a of a Max and an + + align:start position:0% +computation of a of a Max and an + + + align:start position:0% +computation of a of a Max and an +addition right so all of that is is + + align:start position:0% +addition right so all of that is is + + + align:start position:0% +addition right so all of that is is +Theta one right because you're not + + align:start position:0% +Theta one right because you're not + + + align:start position:0% +Theta one right because you're not +counting the recursive calls okay so uh + + align:start position:0% +counting the recursive calls okay so uh + + + align:start position:0% +counting the recursive calls okay so uh +this is our first example I'm I'm uh + + align:start position:0% +this is our first example I'm I'm uh + + + align:start position:0% +this is our first example I'm I'm uh +done with it uh any questions about it + + align:start position:0% +done with it uh any questions about it + + + align:start position:0% +done with it uh any questions about it +any questions about DP in + + align:start position:0% +any questions about DP in + + + align:start position:0% +any questions about DP in +general all right good uh so little bit + + align:start position:0% +general all right good uh so little bit + + + align:start position:0% +general all right good uh so little bit +of review there + + align:start position:0% +of review there + + + align:start position:0% +of review there +uh not a particularly complicated + + align:start position:0% +uh not a particularly complicated + + + align:start position:0% +uh not a particularly complicated +question uh let's uh go to a different + + align:start position:0% +question uh let's uh go to a different + + + align:start position:0% +question uh let's uh go to a different +question corresponding to Optimal binary + + align:start position:0% +question corresponding to Optimal binary + + + align:start position:0% +question corresponding to Optimal binary +search trees it's a very different + + align:start position:0% +search trees it's a very different + + + align:start position:0% +search trees it's a very different +question I I don't think I need this + + align:start position:0% + + + + align:start position:0% + +anymore and it's kind of cute in its own + + align:start position:0% +anymore and it's kind of cute in its own + + + align:start position:0% +anymore and it's kind of cute in its own +way one of the things that's interesting + + align:start position:0% +way one of the things that's interesting + + + align:start position:0% +way one of the things that's interesting +about this question + + align:start position:0% +about this question + + + align:start position:0% +about this question +is is it seems like a greedy algorithm + + align:start position:0% +is is it seems like a greedy algorithm + + + align:start position:0% +is is it seems like a greedy algorithm +should work and we'll talk about that in + + align:start position:0% +should work and we'll talk about that in + + + align:start position:0% +should work and we'll talk about that in +as to why the greedy algorithm you know + + align:start position:0% +as to why the greedy algorithm you know + + + align:start position:0% +as to why the greedy algorithm you know +doesn't quite work so it's kind of + + align:start position:0% +doesn't quite work so it's kind of + + + align:start position:0% +doesn't quite work so it's kind of +similar to the interval scheduling and + + align:start position:0% +similar to the interval scheduling and + + + align:start position:0% +similar to the interval scheduling and +the weighted interval scheduling problem + + align:start position:0% +the weighted interval scheduling problem + + + align:start position:0% +the weighted interval scheduling problem +that we had back in February where the + + align:start position:0% +that we had back in February where the + + + align:start position:0% +that we had back in February where the +regular interval scheduling problem + + align:start position:0% +regular interval scheduling problem + + + align:start position:0% +regular interval scheduling problem +greedy worked earliest finish time + + align:start position:0% +greedy worked earliest finish time + + + align:start position:0% +greedy worked earliest finish time +worked uh but when it came to weights we + + align:start position:0% +worked uh but when it came to weights we + + + align:start position:0% +worked uh but when it came to weights we +had to + + align:start position:0% +had to + + + align:start position:0% +had to +graduate um to dynamic programming so um + + align:start position:0% +graduate um to dynamic programming so um + + + align:start position:0% +graduate um to dynamic programming so um +here's our second problem optimal bsts + + align:start position:0% +here's our second problem optimal bsts + + + align:start position:0% +here's our second problem optimal bsts +right so what is an optimal + + align:start position:0% +right so what is an optimal + + + align:start position:0% +right so what is an optimal +bstd um we have a bunch of + + align:start position:0% +bstd um we have a bunch of + + + align:start position:0% +bstd um we have a bunch of +keys that we want to store in the BST K1 + + align:start position:0% +keys that we want to store in the BST K1 + + + align:start position:0% +keys that we want to store in the BST K1 +through KNN and um we'll assume that the + + align:start position:0% +through KNN and um we'll assume that the + + + align:start position:0% +through KNN and um we'll assume that the +way this is set up is that K1 is less + + align:start position:0% +way this is set up is that K1 is less + + + align:start position:0% +way this is set up is that K1 is less +than K2 da d da less than KNN and just + + align:start position:0% +than K2 da d da less than KNN and just + + + align:start position:0% +than K2 da d da less than KNN and just +to make our life easier in our examples + + align:start position:0% +to make our life easier in our examples + + + align:start position:0% +to make our life easier in our examples +I we'll just assume that Ki equals + + align:start position:0% +I we'll just assume that Ki equals + + + align:start position:0% +I we'll just assume that Ki equals +I um that's not necessarily required for + + align:start position:0% +I um that's not necessarily required for + + + align:start position:0% +I um that's not necessarily required for +anything we're going to do next is just + + align:start position:0% +anything we're going to do next is just + + + align:start position:0% +anything we're going to do next is just +for the sake of examples and keeping + + align:start position:0% +for the sake of examples and keeping + + + align:start position:0% +for the sake of examples and keeping +things + + align:start position:0% +things + + + align:start position:0% +things +manageable so I got a bunch of keys and + + align:start position:0% +manageable so I got a bunch of keys and + + + align:start position:0% +manageable so I got a bunch of keys and +clearly there are many different binary + + align:start position:0% +clearly there are many different binary + + + align:start position:0% +clearly there are many different binary +search trees that uh can come uh whether + + align:start position:0% +search trees that uh can come uh whether + + + align:start position:0% +search trees that uh can come uh whether +they're balanced or unbalanced many + + align:start position:0% +they're balanced or unbalanced many + + + align:start position:0% +they're balanced or unbalanced many +different binary search trees can be + + align:start position:0% +different binary search trees can be + + + align:start position:0% +different binary search trees can be +consistent with uh a given set of keys + + align:start position:0% +consistent with uh a given set of keys + + + align:start position:0% +consistent with uh a given set of keys +right if I choose the root to be uh KNN + + align:start position:0% +right if I choose the root to be uh KNN + + + align:start position:0% +right if I choose the root to be uh KNN +then I'm going to get this horribly + + align:start position:0% +then I'm going to get this horribly + + + align:start position:0% +then I'm going to get this horribly +unbalanced tree right if I chose the + + align:start position:0% +unbalanced tree right if I chose the + + + align:start position:0% +unbalanced tree right if I chose the +root to be somewhere in the middle then + + align:start position:0% +root to be somewhere in the middle then + + + align:start position:0% +root to be somewhere in the middle then +I'm going to get something that looks a + + align:start position:0% +I'm going to get something that looks a + + + align:start position:0% +I'm going to get something that looks a +little better at least at the top level + + align:start position:0% +little better at least at the top level + + + align:start position:0% +little better at least at the top level +but again if I messed it up at the next + + align:start position:0% +but again if I messed it up at the next + + + align:start position:0% +but again if I messed it up at the next +level I'd get something that's + + align:start position:0% +level I'd get something that's + + + align:start position:0% +level I'd get something that's +unbalanced right so there's clearly many + + align:start position:0% +unbalanced right so there's clearly many + + + align:start position:0% +unbalanced right so there's clearly many +different bsts uh I'm not talking about + + align:start position:0% +different bsts uh I'm not talking about + + + align:start position:0% +different bsts uh I'm not talking about +balanced bsts here but we're going to + + align:start position:0% +balanced bsts here but we're going to + + + align:start position:0% +balanced bsts here but we're going to +Define an optimality Criterion that's a + + align:start position:0% +Define an optimality Criterion that's a + + + align:start position:0% +Define an optimality Criterion that's a +little bit different from balanced bsts + + align:start position:0% +little bit different from balanced bsts + + + align:start position:0% +little bit different from balanced bsts +because it's going to have this + + align:start position:0% +because it's going to have this + + + align:start position:0% +because it's going to have this +additional cost function associated with + + align:start position:0% +additional cost function associated with + + + align:start position:0% +additional cost function associated with +it that corresponds to the weight of the + + align:start position:0% +it that corresponds to the weight of the + + + align:start position:0% +it that corresponds to the weight of the +keys okay so what is that well I'm going + + align:start position:0% +keys okay so what is that well I'm going + + + align:start position:0% +keys okay so what is that well I'm going +to have + + align:start position:0% +to have + + + align:start position:0% +to have +weights um associated with each of these + + align:start position:0% +weights um associated with each of these + + + align:start position:0% +weights um associated with each of these +Keys corresponding to W1 through WN and + + align:start position:0% +Keys corresponding to W1 through WN and + + + align:start position:0% +Keys corresponding to W1 through WN and +um the easiest way to uh motivate + + align:start position:0% + + + + align:start position:0% + +you to think that um these weights are + + align:start position:0% +you to think that um these weights are + + + align:start position:0% +you to think that um these weights are +an interesting addition to this problem + + align:start position:0% +an interesting addition to this problem + + + align:start position:0% +an interesting addition to this problem +is to think about these weights as being + + align:start position:0% +is to think about these weights as being + + + align:start position:0% +is to think about these weights as being +search probabilities so what you have + + align:start position:0% +search probabilities so what you have + + + align:start position:0% +search probabilities so what you have +for argument sake is a is a static + + align:start position:0% +for argument sake is a is a static + + + align:start position:0% +for argument sake is a is a static +structure that you've created uh and I + + align:start position:0% +structure that you've created uh and I + + + align:start position:0% +structure that you've created uh and I +mean you could modify it there's nothing + + align:start position:0% +mean you could modify it there's nothing + + + align:start position:0% +mean you could modify it there's nothing +that stopping you from doing that but + + align:start position:0% +that stopping you from doing that but + + + align:start position:0% +that stopping you from doing that but +let's just pretend for now that it's a + + align:start position:0% +let's just pretend for now that it's a + + + align:start position:0% +let's just pretend for now that it's a +static structure corresponding to this + + align:start position:0% +static structure corresponding to this + + + align:start position:0% +static structure corresponding to this +BST has a particular structure and um + + align:start position:0% +BST has a particular structure and um + + + align:start position:0% +BST has a particular structure and um +chances are you're going to be searching + + align:start position:0% +chances are you're going to be searching + + + align:start position:0% +chances are you're going to be searching +for some keys more frequently than + + align:start position:0% +for some keys more frequently than + + + align:start position:0% +for some keys more frequently than +others and the wi tell you what the + + align:start position:0% +others and the wi tell you what the + + + align:start position:0% +others and the wi tell you what the +probabilities are in terms of searching + + align:start position:0% +probabilities are in terms of searching + + + align:start position:0% +probabilities are in terms of searching +for a particular key Ki right so you can + + align:start position:0% +for a particular key Ki right so you can + + + align:start position:0% +for a particular key Ki right so you can +imagine and we won't have this here that + + align:start position:0% +imagine and we won't have this here that + + + align:start position:0% +imagine and we won't have this here that +uh you take the wi all sum up to one if + + align:start position:0% +uh you take the wi all sum up to one if + + + align:start position:0% +uh you take the wi all sum up to one if +you want to think of them as + + align:start position:0% +you want to think of them as + + + align:start position:0% +you want to think of them as +probabilities or you can just I'm just + + align:start position:0% +probabilities or you can just I'm just + + + align:start position:0% +probabilities or you can just I'm just +going to give you numbers I don't want + + align:start position:0% +going to give you numbers I don't want + + + align:start position:0% +going to give you numbers I don't want +to deal with fractions no don't + + align:start position:0% +to deal with fractions no don't + + + align:start position:0% +to deal with fractions no don't +particularly like fractions uh so uh you + + align:start position:0% +particularly like fractions uh so uh you + + + align:start position:0% +particularly like fractions uh so uh you +can imagine that each probability + + align:start position:0% +can imagine that each probability + + + align:start position:0% +can imagine that each probability +corresponds to a wi divided by the sum + + align:start position:0% +corresponds to a wi divided by the sum + + + align:start position:0% +corresponds to a wi divided by the sum +of all of the wi if you want all of the + + align:start position:0% +of all of the wi if you want all of the + + + align:start position:0% +of all of the wi if you want all of the +probabilities to sum up to one okay but + + align:start position:0% +probabilities to sum up to one okay but + + + align:start position:0% +probabilities to sum up to one okay but +so think of them as search probabilities + + align:start position:0% +so think of them as search probabilities + + + align:start position:0% +so think of them as search probabilities +because then you'll see what the point + + align:start position:0% +because then you'll see what the point + + + align:start position:0% +because then you'll see what the point +of this exercise is uh and the point of + + align:start position:0% +of this exercise is uh and the point of + + + align:start position:0% +of this exercise is uh and the point of +this exercise is to + + align:start position:0% +this exercise is to + + + align:start position:0% +this exercise is to +find the BST T so we're actually + + align:start position:0% +find the BST T so we're actually + + + align:start position:0% +find the BST T so we're actually +constructing a binary search Tre here so + + align:start position:0% +constructing a binary search Tre here so + + + align:start position:0% +constructing a binary search Tre here so +it's a little more interesting than than + + align:start position:0% +it's a little more interesting than than + + + align:start position:0% +it's a little more interesting than than +a subsequence for example it has a + + align:start position:0% +a subsequence for example it has a + + + align:start position:0% +a subsequence for example it has a +richer structure associated with it + + align:start position:0% +richer structure associated with it + + + align:start position:0% +richer structure associated with it +there are an exponential number of + + align:start position:0% +there are an exponential number of + + + align:start position:0% +there are an exponential number of +possible binary search trees that are + + align:start position:0% +possible binary search trees that are + + + align:start position:0% +possible binary search trees that are +associated with a given set of n keys + + align:start position:0% +associated with a given set of n keys + + + align:start position:0% +associated with a given set of n keys +that are all you know binary searches + + align:start position:0% +that are all you know binary searches + + + align:start position:0% +that are all you know binary searches +they're consistent unbalanced balanced + + align:start position:0% +they're consistent unbalanced balanced + + + align:start position:0% +they're consistent unbalanced balanced +you know unbalanced in one way versus + + align:start position:0% +you know unbalanced in one way versus + + + align:start position:0% +you know unbalanced in one way versus +another way etc etc + + align:start position:0% +another way etc etc + + + align:start position:0% +another way etc etc +so we want to find a binary sech stre T + + align:start position:0% +so we want to find a binary sech stre T + + + align:start position:0% +so we want to find a binary sech stre T +that uh + + align:start position:0% + + + + align:start position:0% + +minimizes um + + align:start position:0% +minimizes um + + + align:start position:0% +minimizes um +Sigma I = 1 through n obviously we're + + align:start position:0% +Sigma I = 1 through n obviously we're + + + align:start position:0% +Sigma I = 1 through n obviously we're +going to have this wi that's the the + + align:start position:0% +going to have this wi that's the the + + + align:start position:0% +going to have this wi that's the the +game here uh + + align:start position:0% +game here uh + + + align:start position:0% +game here uh +depth uh in the T So this depth is for + + align:start position:0% +depth uh in the T So this depth is for + + + align:start position:0% +depth uh in the T So this depth is for +the T what is the depth of the node um + + align:start position:0% +the T what is the depth of the node um + + + align:start position:0% +the T what is the depth of the node um +and K of I + one + + align:start position:0% +and K of I + one + + + align:start position:0% +and K of I + one +okay um and I'll explain exactly what + + align:start position:0% +okay um and I'll explain exactly what + + + align:start position:0% +okay um and I'll explain exactly what +this is and I tell you what precisely + + align:start position:0% +this is and I tell you what precisely + + + align:start position:0% +this is and I tell you what precisely +the depth is uh but roughly speaking uh + + align:start position:0% +the depth is uh but roughly speaking uh + + + align:start position:0% +the depth is uh but roughly speaking uh +the depth of the root not roughly + + align:start position:0% +the depth of the root not roughly + + + align:start position:0% +the depth of the root not roughly +speaking the depth of the root is zero + + align:start position:0% +speaking the depth of the root is zero + + + align:start position:0% +speaking the depth of the root is zero +okay uh and uh the the depth of one + + align:start position:0% +okay uh and uh the the depth of one + + + align:start position:0% +okay uh and uh the the depth of one +below the root is one and so on and so + + align:start position:0% +below the root is one and so on and so + + + align:start position:0% +below the root is one and so on and so +forth um and so as you can see what you + + align:start position:0% +forth um and so as you can see what you + + + align:start position:0% +forth um and so as you can see what you +want to do is collect uh in roughly + + align:start position:0% +want to do is collect uh in roughly + + + align:start position:0% +want to do is collect uh in roughly +speaking you want to collect the high + + align:start position:0% +speaking you want to collect the high + + + align:start position:0% +speaking you want to collect the high +weight nodes to have L depth right if wi + + align:start position:0% +weight nodes to have L depth right if wi + + + align:start position:0% +weight nodes to have L depth right if wi +is high you want the the multiplicative + + align:start position:0% +is high you want the the multiplicative + + + align:start position:0% +is high you want the the multiplicative +Factor corresponding to depth T of that + + align:start position:0% +Factor corresponding to depth T of that + + + align:start position:0% +Factor corresponding to depth T of that +node I the I node to be to be small and + + align:start position:0% +node I the I node to be to be small and + + + align:start position:0% +node I the I node to be to be small and +if wi is small then you don't mind the + + align:start position:0% +if wi is small then you don't mind the + + + align:start position:0% +if wi is small then you don't mind the +depth uh number to be higher uh you only + + align:start position:0% +depth uh number to be higher uh you only + + + align:start position:0% +depth uh number to be higher uh you only +have a certain number of a low depth + + align:start position:0% +have a certain number of a low depth + + + align:start position:0% +have a certain number of a low depth +nodes you only have one node of depth + + align:start position:0% +nodes you only have one node of depth + + + align:start position:0% +nodes you only have one node of depth +zero and you have two nodes of depth uh + + align:start position:0% +zero and you have two nodes of depth uh + + + align:start position:0% +zero and you have two nodes of depth uh +uh one which means that you only have + + align:start position:0% +uh one which means that you only have + + + align:start position:0% +uh one which means that you only have +one node where that quantity there is + + align:start position:0% +one node where that quantity there is + + + align:start position:0% +one node where that quantity there is +going to be one right because you're + + align:start position:0% +going to be one right because you're + + + align:start position:0% +going to be one right because you're +doing 0 plus one and you have two nodes + + align:start position:0% +doing 0 plus one and you have two nodes + + + align:start position:0% +doing 0 plus one and you have two nodes +where the quantity is going to be two um + + align:start position:0% +where the quantity is going to be two um + + + align:start position:0% +where the quantity is going to be two um +and so on and so forth so you have some + + align:start position:0% +and so on and so forth so you have some + + + align:start position:0% +and so on and so forth so you have some +room here to play with corresponding to + + align:start position:0% +room here to play with corresponding to + + + align:start position:0% +room here to play with corresponding to +the BST structure and you want to + + align:start position:0% +the BST structure and you want to + + + align:start position:0% +the BST structure and you want to +minimize that quantity okay um any + + align:start position:0% +minimize that quantity okay um any + + + align:start position:0% +minimize that quantity okay um any +questions so + + align:start position:0% +questions so + + + align:start position:0% +questions so +far all right good um so uh the search + + align:start position:0% +far all right good um so uh the search + + + align:start position:0% +far all right good um so uh the search +probabilities would be an example so I + + align:start position:0% +probabilities would be an example so I + + + align:start position:0% +probabilities would be an example so I +in terms of a more concrete application + + align:start position:0% +in terms of a more concrete application + + + align:start position:0% +in terms of a more concrete application +you could imagine you had a a + + align:start position:0% +you could imagine you had a a + + + align:start position:0% +you could imagine you had a a +dictionary English to French French to + + align:start position:0% +dictionary English to French French to + + + align:start position:0% +dictionary English to French French to +English what have you and um there're + + align:start position:0% +English what have you and um there're + + + align:start position:0% +English what have you and um there're +obviously words that are more common + + align:start position:0% +obviously words that are more common + + + align:start position:0% +obviously words that are more common +let's say in uh uh common speech than + + align:start position:0% +let's say in uh uh common speech than + + + align:start position:0% +let's say in uh uh common speech than +others and you do want to do the + + align:start position:0% +others and you do want to do the + + + align:start position:0% +others and you do want to do the +translation uh in a dynamic way using + + align:start position:0% +translation uh in a dynamic way using + + + align:start position:0% +translation uh in a dynamic way using +this data structure and you could + + align:start position:0% +this data structure and you could + + + align:start position:0% +this data structure and you could +imagine that in this case the uh the + + align:start position:0% +imagine that in this case the uh the + + + align:start position:0% +imagine that in this case the uh the +search probability of a word is + + align:start position:0% +search probability of a word is + + + align:start position:0% +search probability of a word is +associated with the uh occurrence of the + + align:start position:0% +associated with the uh occurrence of the + + + align:start position:0% +associated with the uh occurrence of the +word the uh the number of times uh over + + align:start position:0% +word the uh the number of times uh over + + + align:start position:0% +word the uh the number of times uh over +some normalized uh uh number of words + + align:start position:0% +some normalized uh uh number of words + + + align:start position:0% +some normalized uh uh number of words +that this particular word occurs and + + align:start position:0% +that this particular word occurs and + + + align:start position:0% +that this particular word occurs and +that would be the that would be the + + align:start position:0% +that would be the that would be the + + + align:start position:0% +that would be the that would be the +weight so it makes sense to create a + + align:start position:0% +weight so it makes sense to create a + + + align:start position:0% +weight so it makes sense to create a +structure that minimizes that function + + align:start position:0% +structure that minimizes that function + + + align:start position:0% +structure that minimizes that function +because it would minimize the expected + + align:start position:0% +because it would minimize the expected + + + align:start position:0% +because it would minimize the expected +search cost when you want to take this + + align:start position:0% +search cost when you want to take this + + + align:start position:0% +search cost when you want to take this +entire uh essay for example and and + + align:start position:0% +entire uh essay for example and and + + + align:start position:0% +entire uh essay for example and and +convert it from English to French or + + align:start position:0% +convert it from English to French or + + + align:start position:0% +convert it from English to French or +vice versa okay so this can if if these + + align:start position:0% +vice versa okay so this can if if these + + + align:start position:0% +vice versa okay so this can if if these +are search probabilities then this would + + align:start position:0% +are search probabilities then this would + + + align:start position:0% +are search probabilities then this would +minimize this cost function here would + + align:start position:0% +minimize this cost function here would + + + align:start position:0% +minimize this cost function here would +minimize + + align:start position:0% + + + + align:start position:0% + +expected search + + align:start position:0% +expected search + + + align:start position:0% +expected search +cost right + + align:start position:0% +cost right + + + align:start position:0% +cost right +um make + + align:start position:0% + + + + align:start position:0% + +sense okay so uh that's the definition + + align:start position:0% +sense okay so uh that's the definition + + + align:start position:0% +sense okay so uh that's the definition +of the problem um and uh now we have to + + align:start position:0% +of the problem um and uh now we have to + + + align:start position:0% +of the problem um and uh now we have to +talk about um why this is complicated + + align:start position:0% +talk about um why this is complicated + + + align:start position:0% +talk about um why this is complicated +why uh this uh requires uh dynamic + + align:start position:0% +why uh this uh requires uh dynamic + + + align:start position:0% +why uh this uh requires uh dynamic +programming uh why can't we um just do + + align:start position:0% +programming uh why can't we um just do + + + align:start position:0% +programming uh why can't we um just do +something fairly straightforward uh like + + align:start position:0% +something fairly straightforward uh like + + + align:start position:0% +something fairly straightforward uh like +a like a grey + + align:start position:0% +a like a grey + + + align:start position:0% +a like a grey +algorithm and so let's look into + + align:start position:0% + + + + align:start position:0% + +that let me give you a really good sense + + align:start position:0% +that let me give you a really good sense + + + align:start position:0% +that let me give you a really good sense +for what's going on here with respect to + + align:start position:0% +for what's going on here with respect to + + + align:start position:0% +for what's going on here with respect to +this cost function that may be a little + + align:start position:0% +this cost function that may be a little + + + align:start position:0% +this cost function that may be a little +abstract by giving you a couple of + + align:start position:0% +abstract by giving you a couple of + + + align:start position:0% +abstract by giving you a couple of +concrete examples uh first off we got + + align:start position:0% +concrete examples uh first off we got + + + align:start position:0% +concrete examples uh first off we got +exponentially many trees + + align:start position:0% + + + + align:start position:0% + +exponential in + + align:start position:0% +exponential in + + + align:start position:0% +exponential in +N let's say that n equals 2 so the + + align:start position:0% +N let's say that n equals 2 so the + + + align:start position:0% +N let's say that n equals 2 so the +number of nodes is two then remember + + align:start position:0% +number of nodes is two then remember + + + align:start position:0% +number of nodes is two then remember +that I'm assuming that the kis Are all + + align:start position:0% +that I'm assuming that the kis Are all + + + align:start position:0% +that I'm assuming that the kis Are all +uh eyes that's the one and two would be + + align:start position:0% +uh eyes that's the one and two would be + + + align:start position:0% +uh eyes that's the one and two would be +uh the K is for uh Nal 2 and 1 2 3 for + + align:start position:0% +uh the K is for uh Nal 2 and 1 2 3 for + + + align:start position:0% +uh the K is for uh Nal 2 and 1 2 3 for +uh K Nal 3 Etc so I could have a tree + + align:start position:0% +uh K Nal 3 Etc so I could have a tree + + + align:start position:0% +uh K Nal 3 Etc so I could have a tree +that looks like that and I could have a + + align:start position:0% +that looks like that and I could have a + + + align:start position:0% +that looks like that and I could have a +tree that looks like this that's it um n + + align:start position:0% +tree that looks like this that's it um n + + + align:start position:0% +tree that looks like this that's it um n +equals 2 I got two trees right so in + + align:start position:0% +equals 2 I got two trees right so in + + + align:start position:0% +equals 2 I got two trees right so in +this case my cost function is W1 + 2 + + align:start position:0% +this case my cost function is W1 + 2 + + + align:start position:0% +this case my cost function is W1 + 2 +W2 and in this case my cost function is + + align:start position:0% +W2 and in this case my cost function is + + + align:start position:0% +W2 and in this case my cost function is +2 W1 + W2 okay um just to be + + align:start position:0% +2 W1 + W2 okay um just to be + + + align:start position:0% +2 W1 + W2 okay um just to be +clear um what this is is the + + align:start position:0% +clear um what this is is the + + + align:start position:0% +clear um what this is is the +uh is is um the K right and it's also + + align:start position:0% +uh is is um the K right and it's also + + + align:start position:0% +uh is is um the K right and it's also +the I so the numbers that you see inside + + align:start position:0% +the I so the numbers that you see inside + + + align:start position:0% +the I so the numbers that you see inside +those are the I numbers which happen to + + align:start position:0% +those are the I numbers which happen to + + + align:start position:0% +those are the I numbers which happen to +be equal to the Ki numbers okay and the + + align:start position:0% +be equal to the Ki numbers okay and the + + + align:start position:0% +be equal to the Ki numbers okay and the +weight itself would be the wi so I put + + align:start position:0% +weight itself would be the wi so I put + + + align:start position:0% +weight itself would be the wi so I put +W1 here and the reason it only gets + + align:start position:0% +W1 here and the reason it only gets + + + align:start position:0% +W1 here and the reason it only gets +multiplied by one is because the depth + + align:start position:0% +multiplied by one is because the depth + + + align:start position:0% +multiplied by one is because the depth +here is zero and I add one to it the + + align:start position:0% +here is zero and I add one to it the + + + align:start position:0% +here is zero and I add one to it the +depth here is one and I add one to it + + align:start position:0% +depth here is one and I add one to it + + + align:start position:0% +depth here is one and I add one to it +which is why I have a two out here okay + + align:start position:0% +which is why I have a two out here okay + + + align:start position:0% +which is why I have a two out here okay +um being a little uh + + align:start position:0% +um being a little uh + + + align:start position:0% +um being a little uh +pedantic here and pointing things out + + align:start position:0% +pedantic here and pointing things out + + + align:start position:0% +pedantic here and pointing things out +because you're going to start seeing + + align:start position:0% +because you're going to start seeing + + + align:start position:0% +because you're going to start seeing +some equations that are a little more + + align:start position:0% +some equations that are a little more + + + align:start position:0% +some equations that are a little more +complicated than this and I don't want + + align:start position:0% +complicated than this and I don't want + + + align:start position:0% +complicated than this and I don't want +you to get confused as to what the + + align:start position:0% +you to get confused as to what the + + + align:start position:0% +you to get confused as to what the +weight is and what the key number is and + + align:start position:0% +weight is and what the key number is and + + + align:start position:0% +weight is and what the key number is and +what the depth is there's three things + + align:start position:0% +what the depth is there's three things + + + align:start position:0% +what the depth is there's three things +going on here okay so over here you see + + align:start position:0% +going on here okay so over here you see + + + align:start position:0% +going on here okay so over here you see +that um I got I'm looking at W1 here + + align:start position:0% +that um I got I'm looking at W1 here + + + align:start position:0% +that um I got I'm looking at W1 here +which is this key right so the the one + + align:start position:0% +which is this key right so the the one + + + align:start position:0% +which is this key right so the the one +corresponds to the one and and this has + + align:start position:0% +corresponds to the one and and this has + + + align:start position:0% +corresponds to the one and and this has +a depth of one so I put a two in here + + align:start position:0% +a depth of one so I put a two in here + + + align:start position:0% +a depth of one so I put a two in here +and so on okay so so far so good um + + align:start position:0% +and so on okay so so far so good um + + + align:start position:0% +and so on okay so so far so good um +when you get to n equals 3 uh you you + + align:start position:0% +when you get to n equals 3 uh you you + + + align:start position:0% +when you get to n equals 3 uh you you +start getting well you have you have at + + align:start position:0% +start getting well you have you have at + + + align:start position:0% +start getting well you have you have at +this point you have u 1 2 3 4 five you + + align:start position:0% +this point you have u 1 2 3 4 five you + + + align:start position:0% +this point you have u 1 2 3 4 five you +got five + + align:start position:0% +got five + + + align:start position:0% +got five +trees uh and uh the trees look like + + align:start position:0% + + + + align:start position:0% + +this I'll draw them really quickly just + + align:start position:0% +this I'll draw them really quickly just + + + align:start position:0% +this I'll draw them really quickly just +to get a sense of the variety here but I + + align:start position:0% +to get a sense of the variety here but I + + + align:start position:0% +to get a sense of the variety here but I +won't write the equations down for um + + align:start position:0% +won't write the equations down for um + + + align:start position:0% +won't write the equations down for um +all of them + + align:start position:0% + + + + align:start position:0% + +there you go so those are the the five + + align:start position:0% +there you go so those are the the five + + + align:start position:0% +there you go so those are the the five +binary trees associated with n equals 3 + + align:start position:0% +binary trees associated with n equals 3 + + + align:start position:0% +binary trees associated with n equals 3 +right the binary search trees um and U + + align:start position:0% +right the binary search trees um and U + + + align:start position:0% +right the binary search trees um and U +this is this is kind of cool uh it's + + align:start position:0% +this is this is kind of cool uh it's + + + align:start position:0% +this is this is kind of cool uh it's +nice and balanced you know the other + + align:start position:0% +nice and balanced you know the other + + + align:start position:0% +nice and balanced you know the other +ones aren't um and I'm not I'm not uh um + + align:start position:0% +ones aren't um and I'm not I'm not uh um + + + align:start position:0% +ones aren't um and I'm not I'm not uh um +looking at U or do should I should I + + align:start position:0% +looking at U or do should I should I + + + align:start position:0% +looking at U or do should I should I +have another one here I guess I should + + align:start position:0% +have another one here I guess I should + + + align:start position:0% +have another one here I guess I should +have + + align:start position:0% + + + + align:start position:0% + +this is a oh no no so I'm not doing + + align:start position:0% +this is a oh no no so I'm not doing + + + align:start position:0% +this is a oh no no so I'm not doing +mirrors uh and so so there is there are + + align:start position:0% +mirrors uh and so so there is there are + + + align:start position:0% +mirrors uh and so so there is there are +a bunch of other trees that have the + + align:start position:0% +a bunch of other trees that have the + + + align:start position:0% +a bunch of other trees that have the +same equation associated with two no + + align:start position:0% +same equation associated with two no + + + align:start position:0% +same equation associated with two no +that's that's not true because uh these + + align:start position:0% +that's that's not true because uh these + + + align:start position:0% +that's that's not true because uh these +are it I I I was going to say that you + + align:start position:0% +are it I I I was going to say that you + + + align:start position:0% +are it I I I was going to say that you +could put three in here but that would + + align:start position:0% +could put three in here but that would + + + align:start position:0% +could put three in here but that would +be a binary search tree right so this + + align:start position:0% +be a binary search tree right so this + + + align:start position:0% +be a binary search tree right so this +this is it uh and we got a bunch of + + align:start position:0% +this is it uh and we got a bunch of + + + align:start position:0% +this is it uh and we got a bunch of +trees this this one would be uh 2 W1 + + + align:start position:0% +trees this this one would be uh 2 W1 + + + + align:start position:0% +trees this this one would be uh 2 W1 + +W2 + 2 W3 + + align:start position:0% +W2 + 2 W3 + + + align:start position:0% +W2 + 2 W3 +by the same process that I used to show + + align:start position:0% +by the same process that I used to show + + + align:start position:0% +by the same process that I used to show +you the W1 + 2 W2 for the N equals 2 + + align:start position:0% +you the W1 + 2 W2 for the N equals 2 + + + align:start position:0% +you the W1 + 2 W2 for the N equals 2 +case you just go off and that's the + + align:start position:0% +case you just go off and that's the + + + align:start position:0% +case you just go off and that's the +equation and so your goal here in an + + align:start position:0% +equation and so your goal here in an + + + align:start position:0% +equation and so your goal here in an +algorithm clearly this is not the + + align:start position:0% +algorithm clearly this is not the + + + align:start position:0% +algorithm clearly this is not the +algorithm you want to enumerate all the + + align:start position:0% +algorithm you want to enumerate all the + + + align:start position:0% +algorithm you want to enumerate all the +exponentially many trees compute the + + align:start position:0% +exponentially many trees compute the + + + align:start position:0% +exponentially many trees compute the +equations for each of those trees and + + align:start position:0% +equations for each of those trees and + + + align:start position:0% +equations for each of those trees and +pick the minimum right I mean that would + + align:start position:0% +pick the minimum right I mean that would + + + align:start position:0% +pick the minimum right I mean that would +work but it would take exponential time + + align:start position:0% +work but it would take exponential time + + + align:start position:0% +work but it would take exponential time +right so uh so but that's what you have + + align:start position:0% +right so uh so but that's what you have + + + align:start position:0% +right so uh so but that's what you have +to do now that's the the goal you + + align:start position:0% +to do now that's the the goal you + + + align:start position:0% +to do now that's the the goal you +absolutely want the best possible tree + + align:start position:0% +absolutely want the best possible tree + + + align:start position:0% +absolutely want the best possible tree +that has for the given wi that you're + + align:start position:0% +that has for the given wi that you're + + + align:start position:0% +that has for the given wi that you're +going to be assigned as constants you do + + align:start position:0% +going to be assigned as constants you do + + + align:start position:0% +going to be assigned as constants you do +want to find the one uh uh threee that + + align:start position:0% +want to find the one uh uh threee that + + + align:start position:0% +want to find the one uh uh threee that +has the minimum sum uh and you want to + + align:start position:0% +has the minimum sum uh and you want to + + + align:start position:0% +has the minimum sum uh and you want to +do that for arbitary n and you want to + + align:start position:0% +do that for arbitary n and you want to + + + align:start position:0% +do that for arbitary n and you want to +do that in polinomial time okay so uh + + align:start position:0% +do that in polinomial time okay so uh + + + align:start position:0% +do that in polinomial time okay so uh +the first thing that you do when you + + align:start position:0% +the first thing that you do when you + + + align:start position:0% +the first thing that you do when you +have something like this + + align:start position:0% +have something like this + + + align:start position:0% +have something like this +is f about the fact that uh we're in a + + align:start position:0% +is f about the fact that uh we're in a + + + align:start position:0% +is f about the fact that uh we're in a +dynamic programming lecture or a dynamic + + align:start position:0% +dynamic programming lecture or a dynamic + + + align:start position:0% +dynamic programming lecture or a dynamic +programming module of this class when + + align:start position:0% +programming module of this class when + + + align:start position:0% +programming module of this class when +you see a problem like this so in the + + align:start position:0% +you see a problem like this so in the + + + align:start position:0% +you see a problem like this so in the +real world uh you want to think about + + align:start position:0% +real world uh you want to think about + + + align:start position:0% +real world uh you want to think about +whether a greedy algorithm would work or + + align:start position:0% +whether a greedy algorithm would work or + + + align:start position:0% +whether a greedy algorithm would work or +not um and uh you don't want to go off + + align:start position:0% +not um and uh you don't want to go off + + + align:start position:0% +not um and uh you don't want to go off +and build this Dynamic program solution + + align:start position:0% +and build this Dynamic program solution + + + align:start position:0% +and build this Dynamic program solution +uh which is chances are going to be in + + align:start position:0% +uh which is chances are going to be in + + + align:start position:0% +uh which is chances are going to be in +more in more uh uh inefficient than a + + align:start position:0% +more in more uh uh inefficient than a + + + align:start position:0% +more in more uh uh inefficient than a +greedy solution which if it produces the + + align:start position:0% +greedy solution which if it produces the + + + align:start position:0% +greedy solution which if it produces the +optimum answer um is the best way to go + + align:start position:0% +optimum answer um is the best way to go + + + align:start position:0% +optimum answer um is the best way to go +so um an obvious greedy solution would + + align:start position:0% +so um an obvious greedy solution would + + + align:start position:0% +so um an obvious greedy solution would +be to pick K of R in + + align:start position:0% +be to pick K of R in + + + align:start position:0% +be to pick K of R in +some greedy + + align:start position:0% + + + + align:start position:0% + +fashion and what is the obvious way of + + align:start position:0% +fashion and what is the obvious way of + + + align:start position:0% +fashion and what is the obvious way of +picking K of R uh to try and get a + + align:start position:0% +picking K of R uh to try and get a + + + align:start position:0% +picking K of R uh to try and get a +greedy solution that at least attempts + + align:start position:0% +greedy solution that at least attempts + + + align:start position:0% +greedy solution that at least attempts +to minimize that cost function that we + + align:start position:0% +to minimize that cost function that we + + + align:start position:0% +to minimize that cost function that we +have there high highest weight right so + + align:start position:0% +have there high highest weight right so + + + align:start position:0% +have there high highest weight right so +just pick K of R to be highest weight + + align:start position:0% +just pick K of R to be highest weight + + + align:start position:0% +just pick K of R to be highest weight +because that goes back to what I said + + align:start position:0% +because that goes back to what I said + + + align:start position:0% +because that goes back to what I said +about if wi is high you + + align:start position:0% +about if wi is high you + + + align:start position:0% +about if wi is high you +want uh this value here to be small + + align:start position:0% +want uh this value here to be small + + + align:start position:0% +want uh this value here to be small +right so that's essentially your greedy + + align:start position:0% +right so that's essentially your greedy + + + align:start position:0% +right so that's essentially your greedy +heuristic so K of R should be picked in + + align:start position:0% +heuristic so K of R should be picked in + + + align:start position:0% +heuristic so K of R should be picked in +a in a greedy fashion so what you do is + + align:start position:0% +a in a greedy fashion so what you do is + + + align:start position:0% +a in a greedy fashion so what you do is +you pick K of r as the root in this + + align:start position:0% +you pick K of r as the root in this + + + align:start position:0% +you pick K of r as the root in this +particular problem and you could + + align:start position:0% +particular problem and you could + + + align:start position:0% +particular problem and you could +certainly apply this greedy technique + + align:start position:0% +certainly apply this greedy technique + + + align:start position:0% +certainly apply this greedy technique +recursively okay so you do that for + + align:start position:0% +recursively okay so you do that for + + + align:start position:0% +recursively okay so you do that for +every sub problem that you find because + + align:start position:0% +every sub problem that you find because + + + align:start position:0% +every sub problem that you find because +when you do this choice of the the root + + align:start position:0% +when you do this choice of the the root + + + align:start position:0% +when you do this choice of the the root +for KR in the current problem that you + + align:start position:0% +for KR in the current problem that you + + + align:start position:0% +for KR in the current problem that you +have you immediately split the keys into + + align:start position:0% +have you immediately split the keys into + + + align:start position:0% +have you immediately split the keys into +two sets right the sets that have to go + + align:start position:0% +two sets right the sets that have to go + + + align:start position:0% +two sets right the sets that have to go +on the left hand side of KR and the sets + + align:start position:0% +on the left hand side of KR and the sets + + + align:start position:0% +on the left hand side of KR and the sets +that have to go on the right hand side + + align:start position:0% +that have to go on the right hand side + + + align:start position:0% +that have to go on the right hand side +of KR right so in this case you know + + align:start position:0% +of KR right so in this case you know + + + align:start position:0% +of KR right so in this case you know +that you're going to have uh a a bunch + + align:start position:0% +that you're going to have uh a a bunch + + + align:start position:0% +that you're going to have uh a a bunch +of keys here that correspond to + + align:start position:0% +of keys here that correspond to + + + align:start position:0% +of keys here that correspond to +KI to + + align:start position:0% +KI to + + + align:start position:0% +KI to +KR and over here um you're going to have + + align:start position:0% +KR and over here um you're going to have + + + align:start position:0% +KR and over here um you're going to have +or KR minus one I should say because you + + align:start position:0% +or KR minus one I should say because you + + + align:start position:0% +or KR minus one I should say because you +already have KR out there and the keys + + align:start position:0% +already have KR out there and the keys + + + align:start position:0% +already have KR out there and the keys +here are going to be KR + one to uh KJ + + align:start position:0% +here are going to be KR + one to uh KJ + + + align:start position:0% +here are going to be KR + one to uh KJ +if + + align:start position:0% +if + + + align:start position:0% +if +overall uh I'm going to say that um e + + align:start position:0% +overall uh I'm going to say that um e + + + align:start position:0% +overall uh I'm going to say that um e +j um + + align:start position:0% +j um + + + align:start position:0% +j um +is the + + align:start position:0% +is the + + + align:start position:0% +is the +cost of the + + align:start position:0% +cost of the + + + align:start position:0% +cost of the +optimal + + align:start position:0% +optimal + + + align:start position:0% +optimal +BST on Ki + + align:start position:0% +BST on Ki + + + align:start position:0% +BST on Ki +k i + + + align:start position:0% +k i + + + + align:start position:0% +k i + + + align:start position:0% + + + align:start position:0% +um all the + + align:start position:0% +um all the + + + align:start position:0% +um all the +way to + + align:start position:0% +way to + + + align:start position:0% +way to +KJ okay so um I'm kind of already + + align:start position:0% +KJ okay so um I'm kind of already + + + align:start position:0% +KJ okay so um I'm kind of already +setting myself up here for uh dynamic + + align:start position:0% +setting myself up here for uh dynamic + + + align:start position:0% +setting myself up here for uh dynamic +programming but it also makes sense in + + align:start position:0% +programming but it also makes sense in + + + align:start position:0% +programming but it also makes sense in +the case of a of a greedy algorithm + + align:start position:0% +the case of a of a greedy algorithm + + + align:start position:0% +the case of a of a greedy algorithm +where this greedy heuristic is going to + + align:start position:0% +where this greedy heuristic is going to + + + align:start position:0% +where this greedy heuristic is going to +be applied recursively okay so initially + + align:start position:0% +be applied recursively okay so initially + + + align:start position:0% +be applied recursively okay so initially +you're going to have uh + + align:start position:0% +you're going to have uh + + + align:start position:0% +you're going to have uh +e1n right so if you want to compute + + align:start position:0% +e1n right so if you want to compute + + + align:start position:0% +e1n right so if you want to compute +e1n which is the cost of the optimal BST + + align:start position:0% +e1n which is the cost of the optimal BST + + + align:start position:0% +e1n which is the cost of the optimal BST +on the original problem all right all + + align:start position:0% +on the original problem all right all + + + align:start position:0% +on the original problem all right all +the way from one to n you're going to + + align:start position:0% +the way from one to n you're going to + + + align:start position:0% +the way from one to n you're going to +look at it and you're going to say uh I + + align:start position:0% +look at it and you're going to say uh I + + + align:start position:0% +look at it and you're going to say uh I +have a bunch of keys here of a different + + align:start position:0% +have a bunch of keys here of a different + + + align:start position:0% +have a bunch of keys here of a different +weights that correspond to K1 through + + align:start position:0% +weights that correspond to K1 through + + + align:start position:0% +weights that correspond to K1 through +KNN I'm going to pick the KR that + + align:start position:0% +KNN I'm going to pick the KR that + + + align:start position:0% +KNN I'm going to pick the KR that +corresponds to the maximum weight and + + align:start position:0% +corresponds to the maximum weight and + + + align:start position:0% +corresponds to the maximum weight and +I'm going to use that as the root node + + align:start position:0% +I'm going to use that as the root node + + + align:start position:0% +I'm going to use that as the root node +and I'm going to stick that up there and + + align:start position:0% +and I'm going to stick that up there and + + + align:start position:0% +and I'm going to stick that up there and +uh the reason I did that uh is because + + align:start position:0% +uh the reason I did that uh is because + + + align:start position:0% +uh the reason I did that uh is because +I'm I believe that this greedy heuristic + + align:start position:0% +I'm I believe that this greedy heuristic + + + align:start position:0% +I'm I believe that this greedy heuristic +is going to work where this maximum + + align:start position:0% +is going to work where this maximum + + + align:start position:0% +is going to work where this maximum +weight node should have the the absolute + + align:start position:0% +weight node should have the the absolute + + + align:start position:0% +weight node should have the the absolute +minimum depth okay so I stick that up + + align:start position:0% +minimum depth okay so I stick that up + + + align:start position:0% +minimum depth okay so I stick that up +there and then my BST invariant tells me + + align:start position:0% +there and then my BST invariant tells me + + + align:start position:0% +there and then my BST invariant tells me +that Ki through KR minus1 remember these + + align:start position:0% +that Ki through KR minus1 remember these + + + align:start position:0% +that Ki through KR minus1 remember these +are sorted right and they go uh in + + align:start position:0% +are sorted right and they go uh in + + + align:start position:0% +are sorted right and they go uh in +increasing order as I have up here uh + + align:start position:0% +increasing order as I have up here uh + + + align:start position:0% +increasing order as I have up here uh +you're going to have those on the left + + align:start position:0% +you're going to have those on the left + + + align:start position:0% +you're going to have those on the left +and you have going to have those on the + + align:start position:0% +and you have going to have those on the + + + align:start position:0% +and you have going to have those on the +right and then you got to go solve this + + align:start position:0% +right and then you got to go solve this + + + align:start position:0% +right and then you got to go solve this +problem and you can certainly apply the + + align:start position:0% +problem and you can certainly apply the + + + align:start position:0% +problem and you can certainly apply the +greedy heuristic to solve this problem + + align:start position:0% +greedy heuristic to solve this problem + + + align:start position:0% +greedy heuristic to solve this problem +right you could go essentially uh find + + align:start position:0% +right you could go essentially uh find + + + align:start position:0% +right you could go essentially uh find +the K uh that uh has the highest weight + + align:start position:0% +the K uh that uh has the highest weight + + + align:start position:0% +the K uh that uh has the highest weight +so you look at wi through w r minus one + + align:start position:0% +so you look at wi through w r minus one + + + align:start position:0% +so you look at wi through w r minus one +and you find the the K that has the + + align:start position:0% +and you find the the K that has the + + + align:start position:0% +and you find the the K that has the +highest weight right so you're not going + + align:start position:0% +highest weight right so you're not going + + + align:start position:0% +highest weight right so you're not going +Midway here it's quite possible that KR + + align:start position:0% +Midway here it's quite possible that KR + + + align:start position:0% +Midway here it's quite possible that KR +is K of n okay it just happens to be KR + + align:start position:0% +is K of n okay it just happens to be KR + + + align:start position:0% +is K of n okay it just happens to be KR +is K of n so so that means that uh uh + + align:start position:0% +is K of n so so that means that uh uh + + + align:start position:0% +is K of n so so that means that uh uh +you have the highest weight node up here + + align:start position:0% +you have the highest weight node up here + + + align:start position:0% +you have the highest weight node up here +but it's also the the biggest key so all + + align:start position:0% +but it's also the the biggest key so all + + + align:start position:0% +but it's also the the biggest key so all +of the nodes are going to be on the left + + align:start position:0% +of the nodes are going to be on the left + + + align:start position:0% +of the nodes are going to be on the left +so this greedy heuristic and now you're + + align:start position:0% +so this greedy heuristic and now you're + + + align:start position:0% +so this greedy heuristic and now you're +starting to see maybe there's a problem + + align:start position:0% +starting to see maybe there's a problem + + + align:start position:0% +starting to see maybe there's a problem +here because uh if you have a situation + + align:start position:0% +here because uh if you have a situation + + + align:start position:0% +here because uh if you have a situation +where uh the the highest weight node is + + align:start position:0% +where uh the the highest weight node is + + + align:start position:0% +where uh the the highest weight node is +also the largest node you're going to + + align:start position:0% +also the largest node you're going to + + + align:start position:0% +also the largest node you're going to +get a pretty unbalanced tree okay so I + + align:start position:0% +get a pretty unbalanced tree okay so I + + + align:start position:0% +get a pretty unbalanced tree okay so I +can tell you that greedy doesn't work + + align:start position:0% +can tell you that greedy doesn't work + + + align:start position:0% +can tell you that greedy doesn't work +and U uh when I gave this lecture I + + align:start position:0% +and U uh when I gave this lecture I + + + align:start position:0% +and U uh when I gave this lecture I +think it was a couple of years ago I I + + align:start position:0% +think it was a couple of years ago I I + + + align:start position:0% +think it was a couple of years ago I I +made that statement and U uh this uh uh + + align:start position:0% +made that statement and U uh this uh uh + + + align:start position:0% +made that statement and U uh this uh uh +annoying student asked me for an example + + align:start position:0% +annoying student asked me for an example + + + align:start position:0% +annoying student asked me for an example +okay and I couldn't come up with one and + + align:start position:0% +okay and I couldn't come up with one and + + + align:start position:0% +okay and I couldn't come up with one and +so I kind of bailed on it went on uh + + align:start position:0% +so I kind of bailed on it went on uh + + + align:start position:0% +so I kind of bailed on it went on uh +completely dissatisfied of course and by + + align:start position:0% +completely dissatisfied of course and by + + + align:start position:0% +completely dissatisfied of course and by +the end of uh the lecture uh the same + + align:start position:0% +the end of uh the lecture uh the same + + + align:start position:0% +the end of uh the lecture uh the same +student came up with a counter example + + align:start position:0% +student came up with a counter example + + + align:start position:0% +student came up with a counter example +right so I'm going to have to put that + + align:start position:0% +right so I'm going to have to put that + + + align:start position:0% +right so I'm going to have to put that +up here + + align:start position:0% +up here + + + align:start position:0% +up here +and uh thank the student who sent me + + align:start position:0% +and uh thank the student who sent me + + + align:start position:0% +and uh thank the student who sent me +a email about + + align:start position:0% +a email about + + + align:start position:0% +a email about +it and so here's a concrete example it + + align:start position:0% +it and so here's a concrete example it + + + align:start position:0% +it and so here's a concrete example it +turns out I was trying to get a three- + + align:start position:0% +turns out I was trying to get a three- + + + align:start position:0% +turns out I was trying to get a three- +Noe example for a few minutes and uh + + align:start position:0% +Noe example for a few minutes and uh + + + align:start position:0% +Noe example for a few minutes and uh +fail it it's it's it's uh I think + + align:start position:0% +fail it it's it's it's uh I think + + + align:start position:0% +fail it it's it's it's uh I think +impossible I haven't proved this to to + + align:start position:0% +impossible I haven't proved this to to + + + align:start position:0% +impossible I haven't proved this to to +find a three Noe example with arbitrary + + align:start position:0% +find a three Noe example with arbitrary + + + align:start position:0% +find a three Noe example with arbitrary +weights for which the greedy algorithm + + align:start position:0% +weights for which the greedy algorithm + + + align:start position:0% +weights for which the greedy algorithm +fails + + align:start position:0% +fails + + + align:start position:0% +fails +okay but four nodes it fails okay so + + align:start position:0% +okay but four nodes it fails okay so + + + align:start position:0% +okay but four nodes it fails okay so +that's the good news um so + + align:start position:0% +that's the good news um so + + + align:start position:0% +that's the good news um so +here's here's the + + align:start position:0% +here's here's the + + + align:start position:0% +here's here's the +example thanks to Nick + + align:start position:0% + + + + align:start position:0% + +Davis and it looks like this + + align:start position:0% + + + + align:start position:0% + +oops so I claim that the greedy + + align:start position:0% +oops so I claim that the greedy + + + align:start position:0% +oops so I claim that the greedy +algorithm for the problem that is given + + align:start position:0% +algorithm for the problem that is given + + + align:start position:0% +algorithm for the problem that is given +to me uh would + + align:start position:0% +to me uh would + + + align:start position:0% +to me uh would +produce this uh BST right and uh the + + align:start position:0% +produce this uh BST right and uh the + + + align:start position:0% +produce this uh BST right and uh the +reason reason for that uh is simple uh + + align:start position:0% +reason reason for that uh is simple uh + + + align:start position:0% +reason reason for that uh is simple uh +the highest weight node happens to be + + align:start position:0% +the highest weight node happens to be + + + align:start position:0% +the highest weight node happens to be +node two which has a weight of 10 so I + + align:start position:0% +node two which has a weight of 10 so I + + + align:start position:0% +node two which has a weight of 10 so I +would pick that and I'd stick that up + + align:start position:0% +would pick that and I'd stick that up + + + align:start position:0% +would pick that and I'd stick that up +here which means of course that I'm + + align:start position:0% +here which means of course that I'm + + + align:start position:0% +here which means of course that I'm +going to have to have one on this side + + align:start position:0% +going to have to have one on this side + + + align:start position:0% +going to have to have one on this side +and I'm going to have to have four and + + align:start position:0% +and I'm going to have to have four and + + + align:start position:0% +and I'm going to have to have four and +three on the other side and since four + + align:start position:0% +three on the other side and since four + + + align:start position:0% +three on the other side and since four +has a higher weight uh than three I'd + + align:start position:0% +has a higher weight uh than three I'd + + + align:start position:0% +has a higher weight uh than three I'd +pick that first and then three would + + align:start position:0% +pick that first and then three would + + + align:start position:0% +pick that first and then three would +have to go over here okay so if I go do + + align:start position:0% +have to go over here okay so if I go do + + + align:start position:0% +have to go over here okay so if I go do +the math um the cost is going to be 1 * + + align:start position:0% +the math um the cost is going to be 1 * + + + align:start position:0% +the math um the cost is going to be 1 * +2 and I'll explain what these numbers + + align:start position:0% +2 and I'll explain what these numbers + + + align:start position:0% +2 and I'll explain what these numbers +are I did tell you it was going to get a + + align:start position:0% +are I did tell you it was going to get a + + + align:start position:0% +are I did tell you it was going to get a +little uh cluttered here with uh with + + align:start position:0% +little uh cluttered here with uh with + + + align:start position:0% +little uh cluttered here with uh with +lots of numbers but if you keep that + + align:start position:0% +lots of numbers but if you keep that + + + align:start position:0% +lots of numbers but if you keep that +equation in mind then this should all + + align:start position:0% +equation in mind then this should all + + + align:start position:0% +equation in mind then this should all +work out um so what do I have here um + + align:start position:0% +work out um so what do I have here um + + + align:start position:0% +work out um so what do I have here um +I'm just Computing this is + + align:start position:0% +I'm just Computing this is + + + align:start position:0% +I'm just Computing this is +W1 so you you see the first numbers in + + align:start position:0% +W1 so you you see the first numbers in + + + align:start position:0% +W1 so you you see the first numbers in +each of these are the are the weights uh + + align:start position:0% +each of these are the are the weights uh + + + align:start position:0% +each of these are the are the weights uh +and so this would be W2 and Etc and you + + align:start position:0% +and so this would be W2 and Etc and you + + + align:start position:0% +and so this would be W2 and Etc and you +can see that this is at + + align:start position:0% +can see that this is at + + + align:start position:0% +can see that this is at +depth one which means I have to have two + + align:start position:0% +depth one which means I have to have two + + + align:start position:0% +depth one which means I have to have two +here because I'm adding one to the depth + + align:start position:0% +here because I'm adding one to the depth + + + align:start position:0% +here because I'm adding one to the depth +so I have 1 * 2 10 * 1 because that's at + + align:start position:0% +so I have 1 * 2 10 * 1 because that's at + + + align:start position:0% +so I have 1 * 2 10 * 1 because that's at +the root 9 * 2 Etc and um I get I get 54 + + align:start position:0% +the root 9 * 2 Etc and um I get I get 54 + + + align:start position:0% +the root 9 * 2 Etc and um I get I get 54 +right it turns out the optimum tree you + + align:start position:0% +right it turns out the optimum tree you + + + align:start position:0% +right it turns out the optimum tree you +can do you can do better than that if + + align:start position:0% +can do you can do better than that if + + + align:start position:0% +can do you can do better than that if +you pick + + align:start position:0% +you pick + + + align:start position:0% +you pick +three um and you + + align:start position:0% +three um and you + + + align:start position:0% +three um and you +go like this + + align:start position:0% + + + + align:start position:0% + +and so what you have here is the cost = + + align:start position:0% +and so what you have here is the cost = + + + align:start position:0% +and so what you have here is the cost = +1 * 3 + 10 * 2 + 8 * 1 + 9 * 2 and + + align:start position:0% +1 * 3 + 10 * 2 + 8 * 1 + 9 * 2 and + + + align:start position:0% +1 * 3 + 10 * 2 + 8 * 1 + 9 * 2 and +that's + + align:start position:0% +that's + + + align:start position:0% +that's + + align:start position:0% + + + align:start position:0% +okay so I'll let you look at that um the + + align:start position:0% +okay so I'll let you look at that um the + + + align:start position:0% +okay so I'll let you look at that um the +bottom line is I it because of the way + + align:start position:0% +bottom line is I it because of the way + + + align:start position:0% +bottom line is I it because of the way +the weights are set up here uh you + + align:start position:0% +the weights are set up here uh you + + + align:start position:0% +the weights are set up here uh you +really want to use the top three + + align:start position:0% +really want to use the top three + + + align:start position:0% +really want to use the top three +spots uh for which have the the minimum + + align:start position:0% +spots uh for which have the the minimum + + + align:start position:0% +spots uh for which have the the minimum +depth uh for the highest weight nodes + + align:start position:0% +depth uh for the highest weight nodes + + + align:start position:0% +depth uh for the highest weight nodes +right and so you can see that I could + + align:start position:0% +right and so you can see that I could + + + align:start position:0% +right and so you can see that I could +make this uh these weights uh arbitrary + + align:start position:0% +make this uh these weights uh arbitrary + + + align:start position:0% +make this uh these weights uh arbitrary +obviously and I could break a greedy + + align:start position:0% +obviously and I could break a greedy + + + align:start position:0% +obviously and I could break a greedy +algorithm as this little example shows + + align:start position:0% +algorithm as this little example shows + + + align:start position:0% +algorithm as this little example shows +right so we got no recurse here we got + + align:start position:0% +right so we got no recurse here we got + + + align:start position:0% +right so we got no recurse here we got +to do some more work we're going to have + + align:start position:0% +to do some more work we're going to have + + + align:start position:0% +to do some more work we're going to have +to use DP to solve this problem the good + + align:start position:0% +to use DP to solve this problem the good + + + align:start position:0% +to use DP to solve this problem the good +news is DP does solve this problem + + align:start position:0% +news is DP does solve this problem + + + align:start position:0% +news is DP does solve this problem +okay um so let Let's uh let's take a + + align:start position:0% +okay um so let Let's uh let's take a + + + align:start position:0% +okay um so let Let's uh let's take a +look at the decomposition and as with + + align:start position:0% +look at the decomposition and as with + + + align:start position:0% +look at the decomposition and as with +anything else uh the key is uh the the + + align:start position:0% +anything else uh the key is uh the the + + + align:start position:0% +anything else uh the key is uh the the +step that corresponds to breaking up the + + align:start position:0% +step that corresponds to breaking up the + + + align:start position:0% +step that corresponds to breaking up the +original problem into two parts uh or + + align:start position:0% +original problem into two parts uh or + + + align:start position:0% +original problem into two parts uh or +more uh that that essentially give you + + align:start position:0% +more uh that that essentially give you + + + align:start position:0% +more uh that that essentially give you +this sort of decomposition and uh we + + align:start position:0% +this sort of decomposition and uh we + + + align:start position:0% +this sort of decomposition and uh we +don't quite know so this is really the + + align:start position:0% +don't quite know so this is really the + + + align:start position:0% +don't quite know so this is really the +key question here we don't quite know + + align:start position:0% +key question here we don't quite know + + + align:start position:0% +key question here we don't quite know +what the root node is going to be so + + align:start position:0% +what the root node is going to be so + + + align:start position:0% +what the root node is going to be so +what is what do we do when we don't know + + align:start position:0% +what is what do we do when we don't know + + + align:start position:0% +what is what do we do when we don't know +what to do + + align:start position:0% +what to do + + + align:start position:0% +what to do +do right what do we do in DP when we + + align:start position:0% +do right what do we do in DP when we + + + align:start position:0% +do right what do we do in DP when we +don't know what to do this is a very + + align:start position:0% +don't know what to do this is a very + + + align:start position:0% +don't know what to do this is a very +profound + + align:start position:0% +profound + + + align:start position:0% +profound +question what do you do you guess and + + align:start position:0% +question what do you do you guess and + + + align:start position:0% +question what do you do you guess and +not only do you guess you guess all + + align:start position:0% +not only do you guess you guess all + + + align:start position:0% +not only do you guess you guess all +outcomes you you you say is it going to + + align:start position:0% +outcomes you you you say is it going to + + + align:start position:0% +outcomes you you you say is it going to +come up heads is it going to come up + + align:start position:0% +come up heads is it going to come up + + + align:start position:0% +come up heads is it going to come up +Tails I'll guess both you have a die + + align:start position:0% +Tails I'll guess both you have a die + + + align:start position:0% +Tails I'll guess both you have a die +it's going to get roll a one 2 3 four 5 + + align:start position:0% +it's going to get roll a one 2 3 four 5 + + + align:start position:0% +it's going to get roll a one 2 3 four 5 +six guess them all right so if you're + + align:start position:0% +six guess them all right so if you're + + + align:start position:0% +six guess them all right so if you're +going to have to guess that the root + + align:start position:0% +going to have to guess that the root + + + align:start position:0% +going to have to guess that the root +node could be any of the any of the keys + + align:start position:0% +node could be any of the any of the keys + + + align:start position:0% +node could be any of the any of the keys +right and it's still I mean there's + + align:start position:0% +right and it's still I mean there's + + + align:start position:0% +right and it's still I mean there's +there's a linear number of guesses there + + align:start position:0% +there's a linear number of guesses there + + + align:start position:0% +there's a linear number of guesses there +that's the good news it's going to stay + + align:start position:0% +that's the good news it's going to stay + + + align:start position:0% +that's the good news it's going to stay +polinomial time okay so we're going to + + align:start position:0% +polinomial time okay so we're going to + + + align:start position:0% +polinomial time okay so we're going to +have to guess and once you do that guess + + align:start position:0% +have to guess and once you do that guess + + + align:start position:0% +have to guess and once you do that guess +it turns out that decomposition that you + + align:start position:0% +it turns out that decomposition that you + + + align:start position:0% +it turns out that decomposition that you +see up there um is exactly what we want + + align:start position:0% +see up there um is exactly what we want + + + align:start position:0% +see up there um is exactly what we want +it's just that the greedy algorithm + + align:start position:0% +it's just that the greedy algorithm + + + align:start position:0% +it's just that the greedy algorithm +didn't bother with all of these + + align:start position:0% +didn't bother with all of these + + + align:start position:0% +didn't bother with all of these +different guesses and the DP is + + align:start position:0% +different guesses and the DP is + + + align:start position:0% +different guesses and the DP is +different from the greedy algorithm + + align:start position:0% +different from the greedy algorithm + + + align:start position:0% +different from the greedy algorithm +because um it's going to do each of + + align:start position:0% +because um it's going to do each of + + + align:start position:0% +because um it's going to do each of +those guesses and he going to pick the + + align:start position:0% +those guesses and he going to pick the + + + align:start position:0% +those guesses and he going to pick the +best one + + align:start position:0% +best one + + + align:start position:0% +best one +that comes out of all of those guesses + + align:start position:0% +that comes out of all of those guesses + + + align:start position:0% +that comes out of all of those guesses +right so it's really not that different + + align:start position:0% +right so it's really not that different + + + align:start position:0% +right so it's really not that different +from greedy right so um we'll keep that + + align:start position:0% +from greedy right so um we'll keep that + + + align:start position:0% +from greedy right so um we'll keep that +up there I leave that here let's go over + + align:start position:0% +up there I leave that here let's go over + + + align:start position:0% +up there I leave that here let's go over +here so the recursion here is not going + + align:start position:0% +here so the recursion here is not going + + + align:start position:0% +here so the recursion here is not going +to be that uh hard once you have gotten + + align:start position:0% +to be that uh hard once you have gotten + + + align:start position:0% +to be that uh hard once you have gotten +the inside that you just have to go make + + align:start position:0% +the inside that you just have to go make + + + align:start position:0% +the inside that you just have to go make +a linear number of guesses corresponding + + align:start position:0% +a linear number of guesses corresponding + + + align:start position:0% +a linear number of guesses corresponding +to the root node for your particular sub + + align:start position:0% +to the root node for your particular sub + + + align:start position:0% +to the root node for your particular sub +problem and obviously this happens + + align:start position:0% +problem and obviously this happens + + + align:start position:0% +problem and obviously this happens +recursively + + align:start position:0% +recursively + + + align:start position:0% +recursively +okay so there's a little subtlety here + + align:start position:0% +okay so there's a little subtlety here + + + align:start position:0% +okay so there's a little subtlety here +that I'll point out with respect to + + align:start position:0% +that I'll point out with respect to + + + align:start position:0% +that I'll point out with respect to +writing these equations out right so + + align:start position:0% +writing these equations out right so + + + align:start position:0% +writing these equations out right so +what I have here just to be clear is + + align:start position:0% +what I have here just to be clear is + + + align:start position:0% +what I have here just to be clear is +what I wrote up there even when I was + + align:start position:0% +what I wrote up there even when I was + + + align:start position:0% +what I wrote up there even when I was +talking about the greedy algorithm I uh + + align:start position:0% +talking about the greedy algorithm I uh + + + align:start position:0% +talking about the greedy algorithm I uh +had the sub problems defined so the + + align:start position:0% +had the sub problems defined so the + + + align:start position:0% +had the sub problems defined so the +original problem is E1 through n uh the + + align:start position:0% +original problem is E1 through n uh the + + + align:start position:0% +original problem is E1 through n uh the +sub problems correspond to uh e + + align:start position:0% +sub problems correspond to uh e + + + align:start position:0% +sub problems correspond to uh e +j and given a sub problem once I make a + + align:start position:0% +j and given a sub problem once I make a + + + align:start position:0% +j and given a sub problem once I make a +root choice I get two sub problems that + + align:start position:0% +root choice I get two sub problems that + + + align:start position:0% +root choice I get two sub problems that +result from the root Choice okay and + + align:start position:0% +result from the root Choice okay and + + + align:start position:0% +result from the root Choice okay and +each of those two sub problems is going + + align:start position:0% +each of those two sub problems is going + + + align:start position:0% +each of those two sub problems is going +to be something and this is something to + + align:start position:0% +to be something and this is something to + + + align:start position:0% +to be something and this is something to +keep in mind as we write these equations + + align:start position:0% +keep in mind as we write these equations + + + align:start position:0% +keep in mind as we write these equations +out they're going to be one level below + + align:start position:0% +out they're going to be one level below + + + align:start position:0% +out they're going to be one level below +the root okay so keep in mind that the + + align:start position:0% +the root okay so keep in mind that the + + + align:start position:0% +the root okay so keep in mind that the +original e j sub problem corresponded to + + align:start position:0% +original e j sub problem corresponded to + + + align:start position:0% +original e j sub problem corresponded to +this level uh but the e i r minus one + + align:start position:0% +this level uh but the e i r minus one + + + align:start position:0% +this level uh but the e i r minus one +problem uh and the e r + one J problem + + align:start position:0% +problem uh and the e r + one J problem + + + align:start position:0% +problem uh and the e r + one J problem +are at one level below okay so keep that + + align:start position:0% +are at one level below okay so keep that + + + align:start position:0% +are at one level below okay so keep that +in mind as we write these equations + + align:start position:0% +in mind as we write these equations + + + align:start position:0% +in mind as we write these equations +out um and so uh what I want to do here + + align:start position:0% +out um and so uh what I want to do here + + + align:start position:0% +out um and so uh what I want to do here +is just write the recurrence and after + + align:start position:0% +is just write the recurrence and after + + + align:start position:0% +is just write the recurrence and after +that Things become fairly mechanical the + + align:start position:0% +that Things become fairly mechanical the + + + align:start position:0% +that Things become fairly mechanical the +fun is in the recurrence right so I got + + align:start position:0% +fun is in the recurrence right so I got + + + align:start position:0% +fun is in the recurrence right so I got +wi if I equals + + align:start position:0% +wi if I equals + + + align:start position:0% +wi if I equals +J right so I'm at this level and uh if I + + align:start position:0% +J right so I'm at this level and uh if I + + + align:start position:0% +J right so I'm at this level and uh if I +just have one node left then um at that + + align:start position:0% +just have one node left then um at that + + + align:start position:0% +just have one node left then um at that +level uh I'm going to pay uh the the + + align:start position:0% +level uh I'm going to pay uh the the + + + align:start position:0% +level uh I'm going to pay uh the the +weight associated with that node uh and + + align:start position:0% +weight associated with that node uh and + + + align:start position:0% +weight associated with that node uh and +I'm going to have to do a certain amount + + align:start position:0% +I'm going to have to do a certain amount + + + align:start position:0% +I'm going to have to do a certain amount +of um um of of multiplication here with + + align:start position:0% +of um um of of multiplication here with + + + align:start position:0% +of um um of of multiplication here with +respect to the depth but I'm just + + align:start position:0% +respect to the depth but I'm just + + + align:start position:0% +respect to the depth but I'm just +talking about EIG as the sub problem + + align:start position:0% +talking about EIG as the sub problem + + + align:start position:0% +talking about EIG as the sub problem +weight just focusing in on that problem + + align:start position:0% +weight just focusing in on that problem + + + align:start position:0% +weight just focusing in on that problem +so if I only have one node it's the root + + align:start position:0% +so if I only have one node it's the root + + + align:start position:0% +so if I only have one node it's the root +node and that weight is going to be wi + + align:start position:0% +node and that weight is going to be wi + + + align:start position:0% +node and that weight is going to be wi +because the root node has depth of zero + + align:start position:0% +because the root node has depth of zero + + + align:start position:0% +because the root node has depth of zero +and I'm going to add one to it right so + + align:start position:0% +and I'm going to add one to it right so + + + align:start position:0% +and I'm going to add one to it right so +for that sub problem I got I got wi all + + align:start position:0% +for that sub problem I got I got wi all + + + align:start position:0% +for that sub problem I got I got wi all +right keep that in mind because that's + + align:start position:0% +right keep that in mind because that's + + + align:start position:0% +right keep that in mind because that's +the only subtlety here with respect to + + align:start position:0% +the only subtlety here with respect to + + + align:start position:0% +the only subtlety here with respect to +these equations making sure that our + + align:start position:0% +these equations making sure that our + + + align:start position:0% +these equations making sure that our +actual cost function that we're + + align:start position:0% +actual cost function that we're + + + align:start position:0% +actual cost function that we're +Computing has the correct uh depth uh + + align:start position:0% +Computing has the correct uh depth uh + + + align:start position:0% +Computing has the correct uh depth uh +multipli cant associated with it okay so + + align:start position:0% +multipli cant associated with it okay so + + + align:start position:0% +multipli cant associated with it okay so +um then we have our linear guessing um + + align:start position:0% +um then we have our linear guessing um + + + align:start position:0% +um then we have our linear guessing um +and uh oh I I I might have said Max at + + align:start position:0% +and uh oh I I I might have said Max at + + + align:start position:0% +and uh oh I I I might have said Max at +some point uh we want to get the the the + + align:start position:0% +some point uh we want to get the the the + + + align:start position:0% +some point uh we want to get the the the +min here and I had min minimize here so + + align:start position:0% +min here and I had min minimize here so + + + align:start position:0% +min here and I had min minimize here so +I think I'd wrote things down correct + + align:start position:0% +I think I'd wrote things down correct + + + align:start position:0% +I think I'd wrote things down correct +but at some point I think I might have + + align:start position:0% +but at some point I think I might have + + + align:start position:0% +but at some point I think I might have +said we want to maximize cost uh uh but + + align:start position:0% +said we want to maximize cost uh uh but + + + align:start position:0% +said we want to maximize cost uh uh but +we do want to minimize cost here + + align:start position:0% +we do want to minimize cost here + + + align:start position:0% +we do want to minimize cost here +corresponding to the uh the search + + align:start position:0% +corresponding to the uh the search + + + align:start position:0% +corresponding to the uh the search +expected search so we're doing a linear + + align:start position:0% +expected search so we're doing a linear + + + align:start position:0% +expected search so we're doing a linear +and uh we're doing a A Min and we're + + align:start position:0% +and uh we're doing a A Min and we're + + + align:start position:0% +and uh we're doing a A Min and we're +going to go off and uh look at each of + + align:start position:0% +going to go off and uh look at each of + + + align:start position:0% +going to go off and uh look at each of +the different uh nodes as being the root + + align:start position:0% +the different uh nodes as being the root + + + align:start position:0% +the different uh nodes as being the root +just like we discussed okay um and what + + align:start position:0% +just like we discussed okay um and what + + + align:start position:0% +just like we discussed okay um and what +I'm going to do here is I'm going to + + align:start position:0% +I'm going to do here is I'm going to + + + align:start position:0% +I'm going to do here is I'm going to +Simply say first that I'm going to look + + align:start position:0% +Simply say first that I'm going to look + + + align:start position:0% +Simply say first that I'm going to look +at e r minus one which corresponds to + + align:start position:0% +at e r minus one which corresponds to + + + align:start position:0% +at e r minus one which corresponds to +this um and I'm going + + align:start position:0% +this um and I'm going + + + align:start position:0% +this um and I'm going +to uh + + align:start position:0% +to uh + + + align:start position:0% +to uh +have plus e of r + 1 comma + + align:start position:0% +have plus e of r + 1 comma + + + align:start position:0% +have plus e of r + 1 comma +J okay and I at this + + align:start position:0% +J okay and I at this + + + align:start position:0% +J okay and I at this +point I + + align:start position:0% +point I + + + align:start position:0% +point I +I don't quite have what I want because I + + align:start position:0% +I don't quite have what I want because I + + + align:start position:0% +I don't quite have what I want because I +haven't actually taken into account the + + align:start position:0% +haven't actually taken into account the + + + align:start position:0% +haven't actually taken into account the +fact that uh the the depth of the EI + + align:start position:0% +fact that uh the the depth of the EI + + + align:start position:0% +fact that uh the the depth of the EI +rus1 and the r+1 J is one more than the + + align:start position:0% +rus1 and the r+1 J is one more than the + + + align:start position:0% +rus1 and the r+1 J is one more than the +eii J right so it's it's one more than + + align:start position:0% +eii J right so it's it's one more than + + + align:start position:0% +eii J right so it's it's one more than +that right and I also haven't taken into + + align:start position:0% +that right and I also haven't taken into + + + align:start position:0% +that right and I also haven't taken into +account the fact that in this case um I + + align:start position:0% +account the fact that in this case um I + + + align:start position:0% +account the fact that in this case um I +definitely need to add a wi as well + + align:start position:0% +definitely need to add a wi as well + + + align:start position:0% +definitely need to add a wi as well +right because I the root node is part of + + align:start position:0% +right because I the root node is part of + + + align:start position:0% +right because I the root node is part of +my solution in both cases in one case it + + align:start position:0% +my solution in both cases in one case it + + + align:start position:0% +my solution in both cases in one case it +ended my solution uh the top case but in + + align:start position:0% +ended my solution uh the top case but in + + + align:start position:0% +ended my solution uh the top case but in +this case it's also the root node as you + + align:start position:0% +this case it's also the root node as you + + + align:start position:0% +this case it's also the root node as you +can see over on the left and I got to + + align:start position:0% +can see over on the left and I got to + + + align:start position:0% +can see over on the left and I got to +add that in there so I definitely need + + align:start position:0% +add that in there so I definitely need + + + align:start position:0% +add that in there so I definitely need +to add a wi here okay and what else do I + + align:start position:0% +to add a wi here okay and what else do I + + + align:start position:0% +to add a wi here okay and what else do I +need to + + align:start position:0% +need to + + + align:start position:0% +need to +add uh from a from from a standpoint of + + align:start position:0% +add uh from a from from a standpoint of + + + align:start position:0% +add uh from a from from a standpoint of +the weights what other weights do I need + + align:start position:0% +the weights what other weights do I need + + + align:start position:0% +the weights what other weights do I need +to add uh to uh to this line yeah go + + align:start position:0% +to add uh to uh to this line yeah go + + + align:start position:0% +to add uh to uh to this line yeah go +ahead first of all should be + + align:start position:0% +ahead first of all should be + + + align:start position:0% +ahead first of all should be +R uh first of all that should be a WR + + align:start position:0% +R uh first of all that should be a WR + + + align:start position:0% +R uh first of all that should be a WR +you're exactly correct you want add and + + align:start position:0% +you're exactly correct you want add and + + + align:start position:0% +you're exactly correct you want add and +you want to add all the weights right uh + + align:start position:0% +you want to add all the weights right uh + + + align:start position:0% +you want to add all the weights right uh +and uh you're exactly right um I have + + align:start position:0% +and uh you're exactly right um I have + + + align:start position:0% +and uh you're exactly right um I have +two more frisbees but I need to use them + + align:start position:0% +two more frisbees but I need to use them + + + align:start position:0% +two more frisbees but I need to use them +for something else okay so you get one + + align:start position:0% +for something else okay so you get one + + + align:start position:0% +for something else okay so you get one +next time right or um do I have more + + align:start position:0% +next time right or um do I have more + + + align:start position:0% +next time right or um do I have more +than + + align:start position:0% +than + + + align:start position:0% +than +that no no I these are precious frisbees + + align:start position:0% +that no no I these are precious frisbees + + + align:start position:0% +that no no I these are precious frisbees +here you know sorry man you + + align:start position:0% +here you know sorry man you + + + align:start position:0% +here you know sorry man you +know um so and you you corrected me too + + align:start position:0% +know um so and you you corrected me too + + + align:start position:0% +know um so and you you corrected me too +sh you know shoot this is this is sad um + + align:start position:0% +sh you know shoot this is this is sad um + + + align:start position:0% +sh you know shoot this is this is sad um +uh so that needed to be a WRR okay uh + + align:start position:0% +uh so that needed to be a WRR okay uh + + + align:start position:0% +uh so that needed to be a WRR okay uh +but you also need to add all of the + + align:start position:0% +but you also need to add all of the + + + align:start position:0% +but you also need to add all of the +nodes that are in here because there one + + align:start position:0% +nodes that are in here because there one + + + align:start position:0% +nodes that are in here because there one +one more level right and now you see why + + align:start position:0% +one more level right and now you see why + + + align:start position:0% +one more level right and now you see why +I made the mistake right I don't usually + + align:start position:0% +I made the mistake right I don't usually + + + align:start position:0% +I made the mistake right I don't usually +make + + align:start position:0% +make + + + align:start position:0% +make +mistakes but what I really want actually + + align:start position:0% +mistakes but what I really want actually + + + align:start position:0% +mistakes but what I really want actually +it's more like you know I don't know a + + align:start position:0% +it's more like you know I don't know a + + + align:start position:0% +it's more like you know I don't know a +few per lecture you know constant order + + align:start position:0% +few per lecture you know constant order + + + align:start position:0% +few per lecture you know constant order +one + + align:start position:0% +one + + + align:start position:0% +one +mistakes right and I'm going to say this + + align:start position:0% +mistakes right and I'm going to say this + + + align:start position:0% +mistakes right and I'm going to say this +is W comma J all right where wi comma J + + align:start position:0% +is W comma J all right where wi comma J + + + align:start position:0% +is W comma J all right where wi comma J +is simply the sum of all of the weights + + align:start position:0% +is simply the sum of all of the weights + + + align:start position:0% +is simply the sum of all of the weights +from I to J okay + + align:start position:0% + + + + align:start position:0% + +so and this makes perfect sense because + + align:start position:0% +so and this makes perfect sense because + + + align:start position:0% +so and this makes perfect sense because +the nice thing is that I don't even need + + align:start position:0% +the nice thing is that I don't even need + + + align:start position:0% +the nice thing is that I don't even need +to put an r in there all right so it's + + align:start position:0% +to put an r in there all right so it's + + + align:start position:0% +to put an r in there all right so it's +uh I I could choose I put particular R + + align:start position:0% +uh I I could choose I put particular R + + + align:start position:0% +uh I I could choose I put particular R +WR R will be in there but all of the + + align:start position:0% +WR R will be in there but all of the + + + align:start position:0% +WR R will be in there but all of the +other nodes are going to be in there + + align:start position:0% +other nodes are going to be in there + + + align:start position:0% +other nodes are going to be in there +anyway right so it doesn't really matter + + align:start position:0% +anyway right so it doesn't really matter + + + align:start position:0% +anyway right so it doesn't really matter +what the r selection is corresponding to + + align:start position:0% +what the r selection is corresponding to + + + align:start position:0% +what the r selection is corresponding to +this term here though I will put it + + align:start position:0% +this term here though I will put it + + + align:start position:0% +this term here though I will put it +inside the uh the the the minimization + + align:start position:0% +inside the uh the the the minimization + + + align:start position:0% +inside the uh the the the minimization +uh this bracket here is closed with that + + align:start position:0% +uh this bracket here is closed with that + + + align:start position:0% +uh this bracket here is closed with that +but you can pull that out because that + + align:start position:0% +but you can pull that out because that + + + align:start position:0% +but you can pull that out because that +doesn't depend on R right it's it's just + + align:start position:0% +doesn't depend on R right it's it's just + + + align:start position:0% +doesn't depend on R right it's it's just +going to be there uh uh for all of the + + align:start position:0% +going to be there uh uh for all of the + + + align:start position:0% +going to be there uh uh for all of the +cases all of the guesses all right so + + align:start position:0% +cases all of the guesses all right so + + + align:start position:0% +cases all of the guesses all right so +that's it that's uh that's our + + align:start position:0% +that's it that's uh that's our + + + align:start position:0% +that's it that's uh that's our +recurrence relationship corresponding to + + align:start position:0% +recurrence relationship corresponding to + + + align:start position:0% +recurrence relationship corresponding to +uh the DP for this particular + + align:start position:0% +uh the DP for this particular + + + align:start position:0% +uh the DP for this particular +problem um you can go figure out what + + align:start position:0% +problem um you can go figure out what + + + align:start position:0% +problem um you can go figure out what +the complexity is and I I have other + + align:start position:0% +the complexity is and I I have other + + + align:start position:0% +the complexity is and I I have other +things to do so we'll move on uh but you + + align:start position:0% +things to do so we'll move on uh but you + + + align:start position:0% +things to do so we'll move on uh but you +can do the same things and these are + + align:start position:0% +can do the same things and these are + + + align:start position:0% +can do the same things and these are +fairly mechanical at this point to go + + align:start position:0% +fairly mechanical at this point to go + + + align:start position:0% +fairly mechanical at this point to go +write code for it trace the solution to + + align:start position:0% +write code for it trace the solution to + + + align:start position:0% +write code for it trace the solution to +get the optimum binary search Tre uh y y + + align:start position:0% +get the optimum binary search Tre uh y y + + + align:start position:0% +get the optimum binary search Tre uh y y +y right uh any questions about this + + align:start position:0% +y right uh any questions about this + + + align:start position:0% +y right uh any questions about this +equation or anything else do people get + + align:start position:0% +equation or anything else do people get + + + align:start position:0% +equation or anything else do people get +that yeah go ahead what is the depth so + + align:start position:0% +that yeah go ahead what is the depth so + + + align:start position:0% +that yeah go ahead what is the depth so +um the depth is getting added by the + + align:start position:0% +um the depth is getting added by the + + + align:start position:0% +um the depth is getting added by the +weights um so basically what's happening + + align:start position:0% +weights um so basically what's happening + + + align:start position:0% +weights um so basically what's happening +is that um as I go deeper into the + + align:start position:0% +is that um as I go deeper into the + + + align:start position:0% +is that um as I go deeper into the +recursion I'm adding the weights and + + align:start position:0% +recursion I'm adding the weights and + + + align:start position:0% +recursion I'm adding the weights and +potentially multiple times depending on + + align:start position:0% +potentially multiple times depending on + + + align:start position:0% +potentially multiple times depending on +the depth right so if you really think + + align:start position:0% +the depth right so if you really think + + + align:start position:0% +the depth right so if you really think +about it this wi + + align:start position:0% +about it this wi + + + align:start position:0% +about it this wi +J added all of these weights but when + + align:start position:0% +J added all of these weights but when + + + align:start position:0% +J added all of these weights but when +you go into this recursion into the EI + + align:start position:0% +you go into this recursion into the EI + + + align:start position:0% +you go into this recursion into the EI +of Rus one well you're going to see I to + + align:start position:0% +of Rus one well you're going to see I to + + + align:start position:0% +of Rus one well you're going to see I to +Rus one in the next level of recursion + + align:start position:0% +Rus one in the next level of recursion + + + align:start position:0% +Rus one in the next level of recursion +so you would have added you know the + + align:start position:0% +so you would have added you know the + + + align:start position:0% +so you would have added you know the +weight again right so it's not the case + + align:start position:0% +weight again right so it's not the case + + + align:start position:0% +weight again right so it's not the case +that the weights are only appearing once + + align:start position:0% +that the weights are only appearing once + + + align:start position:0% +that the weights are only appearing once +they're in fact appearing this many + + align:start position:0% +they're in fact appearing this many + + + align:start position:0% +they're in fact appearing this many +times right so that's what's kind of + + align:start position:0% +times right so that's what's kind of + + + align:start position:0% +times right so that's what's kind of +cute about this right the way the way we + + align:start position:0% +cute about this right the way the way we + + + align:start position:0% +cute about this right the way the way we +wrote it + + align:start position:0% +wrote it + + + align:start position:0% +wrote it +okay uh any other + + align:start position:0% +okay uh any other + + + align:start position:0% +okay uh any other +questions all right good so uh we're + + align:start position:0% +questions all right good so uh we're + + + align:start position:0% +questions all right good so uh we're +done with that so one last example um + + align:start position:0% +done with that so one last example um + + + align:start position:0% +done with that so one last example um +this is again a little bit different uh + + align:start position:0% +this is again a little bit different uh + + + align:start position:0% +this is again a little bit different uh +from uh the examples of DP we've looked + + align:start position:0% +from uh the examples of DP we've looked + + + align:start position:0% +from uh the examples of DP we've looked +at up until now because it's it's a game + + align:start position:0% +at up until now because it's it's a game + + + align:start position:0% +at up until now because it's it's a game +and you have an opponent and U you have + + align:start position:0% +and you have an opponent and U you have + + + align:start position:0% +and you have an opponent and U you have +to figure out what the opponent is going + + align:start position:0% +to figure out what the opponent is going + + + align:start position:0% +to figure out what the opponent is going +to do uh and you know try to try to + + align:start position:0% +to do uh and you know try to try to + + + align:start position:0% +to do uh and you know try to try to +win uh I guess you suppose you could try + + align:start position:0% +win uh I guess you suppose you could try + + + align:start position:0% +win uh I guess you suppose you could try +to lose as well but um let's assume here + + align:start position:0% +to lose as well but um let's assume here + + + align:start position:0% +to lose as well but um let's assume here +same thing with minimization and + + align:start position:0% +same thing with minimization and + + + align:start position:0% +same thing with minimization and +maximization uh most of the time you can + + align:start position:0% +maximization uh most of the time you can + + + align:start position:0% +maximization uh most of the time you can +U invert these cost functions and DP + + align:start position:0% +U invert these cost functions and DP + + + align:start position:0% +U invert these cost functions and DP +will still work but let's assume here + + align:start position:0% +will still work but let's assume here + + + align:start position:0% +will still work but let's assume here +that you want to win this game right so + + align:start position:0% +that you want to win this game right so + + + align:start position:0% +that you want to win this game right so +uh so the game is an alternating coins + + align:start position:0% +uh so the game is an alternating coins + + + align:start position:0% +uh so the game is an alternating coins +game + + align:start position:0% +game + + + align:start position:0% +game +where we have a row of n + + align:start position:0% +where we have a row of n + + + align:start position:0% +where we have a row of n +coins um of + + align:start position:0% +coins um of + + + align:start position:0% +coins um of +values + + align:start position:0% +values + + + align:start position:0% +values +V1 through VN um these are not + + align:start position:0% +V1 through VN um these are not + + + align:start position:0% +V1 through VN um these are not +necessarily in any particular order uh + + align:start position:0% +necessarily in any particular order uh + + + align:start position:0% +necessarily in any particular order uh +it and N is + + align:start position:0% +it and N is + + + align:start position:0% +it and N is +even and um uh the goal here is uh + + align:start position:0% +even and um uh the goal here is uh + + + align:start position:0% +even and um uh the goal here is uh +select the outer coins so uh select uh + + align:start position:0% +select the outer coins so uh select uh + + + align:start position:0% +select the outer coins so uh select uh +either the + + align:start position:0% +either the + + + align:start position:0% +either the +first or + + align:start position:0% +first or + + + align:start position:0% +first or +last + + align:start position:0% +last + + + align:start position:0% +last +coin uh from the + + align:start position:0% +coin uh from the + + + align:start position:0% +coin uh from the +row and then the uh opponent Place + + align:start position:0% +row and then the uh opponent Place + + + align:start position:0% +row and then the uh opponent Place +remove permanently but add it to your + + align:start position:0% + + + + align:start position:0% + +value and receive the value + + align:start position:0% + + + + align:start position:0% + +all right so I need two + + align:start position:0% +all right so I need two + + + align:start position:0% +all right so I need two +volunteers to play this game and uh you + + align:start position:0% +volunteers to play this game and uh you + + + align:start position:0% +volunteers to play this game and uh you +want to maximize the value the winner + + align:start position:0% +want to maximize the value the winner + + + align:start position:0% +want to maximize the value the winner +gets a blue + + align:start position:0% +gets a blue + + + align:start position:0% +gets a blue +frisbee the loser gets a purple frisbee + + align:start position:0% +frisbee the loser gets a purple frisbee + + + align:start position:0% +frisbee the loser gets a purple frisbee +because blue is greater than + + align:start position:0% +because blue is greater than + + + align:start position:0% +because blue is greater than +purple and and you might ask why is that + + align:start position:0% +purple and and you might ask why is that + + + align:start position:0% +purple and and you might ask why is that +well if you went to a + + align:start position:0% +well if you went to a + + + align:start position:0% +well if you went to a +beach and you saw water this color you + + align:start position:0% +beach and you saw water this color you + + + align:start position:0% +beach and you saw water this color you +went to another Beach and you saw water + + align:start position:0% +went to another Beach and you saw water + + + align:start position:0% +went to another Beach and you saw water +this color which beach would you pick + + align:start position:0% +this color which beach would you pick + + + align:start position:0% +this color which beach would you pick +right this is cuml this is Boston Harbor + + align:start position:0% +right this is cuml this is Boston Harbor + + + align:start position:0% +right this is cuml this is Boston Harbor +right right so blue is greater than + + align:start position:0% +right right so blue is greater than + + + align:start position:0% +right right so blue is greater than +purple right don't use this proof + + align:start position:0% +purple right don't use this proof + + + align:start position:0% +purple right don't use this proof +technique in the quiz all right so do I + + align:start position:0% +technique in the quiz all right so do I + + + align:start position:0% +technique in the quiz all right so do I +have a couple of volunteers to play this + + align:start position:0% +have a couple of volunteers to play this + + + align:start position:0% +have a couple of volunteers to play this +game two of them over there or are you + + align:start position:0% +game two of them over there or are you + + + align:start position:0% +game two of them over there or are you +were waving for him yeah I I see one you + + align:start position:0% +were waving for him yeah I I see one you + + + align:start position:0% +were waving for him yeah I I see one you +can come down another + + align:start position:0% +can come down another + + + align:start position:0% +can come down another +volunteer right y over there right all + + align:start position:0% +volunteer right y over there right all + + + align:start position:0% +volunteer right y over there right all +right you don't get your fris PES yet so + + align:start position:0% +right you don't get your fris PES yet so + + + align:start position:0% +right you don't get your fris PES yet so +um we going to make this really fair + + align:start position:0% +um we going to make this really fair + + + align:start position:0% +um we going to make this really fair +right uh what's your name Josiah Josiah + + align:start position:0% +right uh what's your name Josiah Josiah + + + align:start position:0% +right uh what's your name Josiah Josiah +Tessa Tessa Josiah uh and Tessa I'm + + align:start position:0% +Tessa Tessa Josiah uh and Tessa I'm + + + align:start position:0% +Tessa Tessa Josiah uh and Tessa I'm +going to write out uh a bunch of it's + + align:start position:0% +going to write out uh a bunch of it's + + + align:start position:0% +going to write out uh a bunch of it's +going to be + + align:start position:0% +going to be + + + align:start position:0% +going to be +a a fairly short game + + align:start position:0% +a a fairly short game + + + align:start position:0% +a a fairly short game +okay and we're going to be really fair + + align:start position:0% +okay and we're going to be really fair + + + align:start position:0% +okay and we're going to be really fair +and we're going to flip a coin to decide + + align:start position:0% +and we're going to flip a coin to decide + + + align:start position:0% +and we're going to flip a coin to decide +whether Josiah goes first you can pick + + align:start position:0% +whether Josiah goes first you can pick + + + align:start position:0% +whether Josiah goes first you can pick +heads or tails uh and or whether Tesla + + align:start position:0% +heads or tails uh and or whether Tesla + + + align:start position:0% +heads or tails uh and or whether Tesla +goes first and you can actually if you + + align:start position:0% +goes first and you can actually if you + + + align:start position:0% +goes first and you can actually if you +win you can let her go first if you want + + align:start position:0% +win you can let her go first if you want + + + align:start position:0% +win you can let her go first if you want +but you get to choose all right so pick + + align:start position:0% +but you get to choose all right so pick + + + align:start position:0% +but you get to choose all right so pick +heads that's heads all right do you want + + align:start position:0% +heads that's heads all right do you want + + + align:start position:0% +heads that's heads all right do you want +to go first or do you want to let Tessa + + align:start position:0% +to go first or do you want to let Tessa + + + align:start position:0% +to go first or do you want to let Tessa +go + + align:start position:0% + + + + align:start position:0% + +first you should go + + align:start position:0% + + + + align:start position:0% + +first all right so um Tessa you get to + + align:start position:0% +first all right so um Tessa you get to + + + align:start position:0% +first all right so um Tessa you get to +go first okay um six six okay so uh + + align:start position:0% +go first okay um six six okay so uh + + + align:start position:0% +go first okay um six six okay so uh +let's just say uh t Okay uh so you get + + align:start position:0% +let's just say uh t Okay uh so you get + + + align:start position:0% +let's just say uh t Okay uh so you get +to choose uh either 25 or four Josiah + + align:start position:0% +to choose uh either 25 or four Josiah + + + align:start position:0% +to choose uh either 25 or four Josiah +well I think I take 25 you think you'll + + align:start position:0% +well I think I take 25 you think you'll + + + align:start position:0% +well I think I take 25 you think you'll +take 25 okay so that's J all right so + + align:start position:0% +take 25 okay so that's J all right so + + + align:start position:0% +take 25 okay so that's J all right so +it's it's now down to four and 19 over + + align:start position:0% +it's it's now down to four and 19 over + + + align:start position:0% +it's it's now down to four and 19 over +here because those are gone so you're + + align:start position:0% +here because those are gone so you're + + + align:start position:0% +here because those are gone so you're +turn again okay um can I take a minute + + align:start position:0% +turn again okay um can I take a minute + + + align:start position:0% +turn again okay um can I take a minute +or should I just uh well you can take + + align:start position:0% +or should I just uh well you can take + + + align:start position:0% +or should I just uh well you can take +you can take uh 30 seconds okay + + align:start position:0% +you can take uh 30 seconds okay + + + align:start position:0% +you can take uh 30 seconds okay +right 19 19 okay + + align:start position:0% + + + + align:start position:0% + +all right PA + + align:start position:0% +all right PA + + + align:start position:0% +all right PA +four all + + align:start position:0% +four all + + + align:start position:0% +four all +right and 42 all right 42 this is one + + align:start position:0% +right and 42 all right 42 this is one + + + align:start position:0% +right and 42 all right 42 this is one +strange game all right all right now we + + align:start position:0% +strange game all right all right now we + + + align:start position:0% +strange game all right all right now we +get to add up the numbers this is going + + align:start position:0% +get to add up the numbers this is going + + + align:start position:0% +get to add up the numbers this is going +to be tight right 4 + 39 is 43 43 + 25 + + align:start position:0% +to be tight right 4 + 39 is 43 43 + 25 + + + align:start position:0% +to be tight right 4 + 39 is 43 43 + 25 +is + + align:start position:0% +is + + + align:start position:0% +is +68 um 42 + 19 is uh 61 61 + 6 is + + align:start position:0% +68 um 42 + 19 is uh 61 61 + 6 is + + + align:start position:0% +68 um 42 + 19 is uh 61 61 + 6 is +67 oo all right well you get frisbees + + align:start position:0% +67 oo all right well you get frisbees + + + align:start position:0% +67 oo all right well you get frisbees +right all right well uh blue for you + + align:start position:0% +right all right well uh blue for you + + + align:start position:0% +right all right well uh blue for you +right I mean you can give her blue if + + align:start position:0% +right I mean you can give her blue if + + + align:start position:0% +right I mean you can give her blue if +you like yeah you prefer purple right + + align:start position:0% +you like yeah you prefer purple right + + + align:start position:0% +you like yeah you prefer purple right +thanks okay good job + + align:start position:0% + + + + align:start position:0% + +um no offenses intended to Josiah and + + align:start position:0% +um no offenses intended to Josiah and + + + align:start position:0% +um no offenses intended to Josiah and +Tessa but that was a classic example of + + align:start position:0% +Tessa but that was a classic example of + + + align:start position:0% +Tessa but that was a classic example of +how not to play the game okay first off + + align:start position:0% +how not to play the game okay first off + + + align:start position:0% +how not to play the game okay first off +Josiah could have won uh regardless of + + align:start position:0% +Josiah could have won uh regardless of + + + align:start position:0% +Josiah could have won uh regardless of +the coins that were up there regardless + + align:start position:0% +the coins that were up there regardless + + + align:start position:0% +the coins that were up there regardless +of the values of the coins if he chosen + + align:start position:0% +of the values of the coins if he chosen + + + align:start position:0% +of the values of the coins if he chosen +to go first right so this game the + + align:start position:0% +to go first right so this game the + + + align:start position:0% +to go first right so this game the +person who goes first is guaranteed to + + align:start position:0% +person who goes first is guaranteed to + + + align:start position:0% +person who goes first is guaranteed to +not lose and by that I mean you uh uh + + align:start position:0% +not lose and by that I mean you uh uh + + + align:start position:0% +not lose and by that I mean you uh uh +may have a situation where you can have + + align:start position:0% +may have a situation where you can have + + + align:start position:0% +may have a situation where you can have +a tie in terms of the values but you're + + align:start position:0% +a tie in terms of the values but you're + + + align:start position:0% +a tie in terms of the values but you're +guaranteed to not lose all right so now + + align:start position:0% +guaranteed to not lose all right so now + + + align:start position:0% +guaranteed to not lose all right so now +he ended up winning anyway because there + + align:start position:0% +he ended up winning anyway because there + + + align:start position:0% +he ended up winning anyway because there +were other errors + + align:start position:0% +were other errors + + + align:start position:0% +were other errors +made uh in in in during this and I don't + + align:start position:0% +made uh in in in during this and I don't + + + align:start position:0% +made uh in in in during this and I don't +have the time to enumerate all of them + + align:start position:0% +have the time to enumerate all of them + + + align:start position:0% +have the time to enumerate all of them +okay so we're just going to go move on + + align:start position:0% +okay so we're just going to go move on + + + align:start position:0% +okay so we're just going to go move on +and uh do the right thing all + + align:start position:0% +and uh do the right thing all + + + align:start position:0% +and uh do the right thing all +right so + + align:start position:0% + + + + align:start position:0% + +so let me first tell you outside of DP + + align:start position:0% +so let me first tell you outside of DP + + + align:start position:0% +so let me first tell you outside of DP +just in case you play this game over + + align:start position:0% +just in case you play this game over + + + align:start position:0% +just in case you play this game over +spring break or + + align:start position:0% +spring break or + + + align:start position:0% +spring break or +something how you can uh win this game + + align:start position:0% +something how you can uh win this game + + + align:start position:0% +something how you can uh win this game +uh without having to compute you know + + align:start position:0% +uh without having to compute you know + + + align:start position:0% +uh without having to compute you know +complicated recursive memorization DP + + align:start position:0% +complicated recursive memorization DP + + + align:start position:0% +complicated recursive memorization DP +programs right for this case Okay so + + align:start position:0% +programs right for this case Okay so + + + align:start position:0% +programs right for this case Okay so +let's say I have V1 V2 V3 all the way to + + align:start position:0% +let's say I have V1 V2 V3 all the way to + + + align:start position:0% +let's say I have V1 V2 V3 all the way to +VN minus one and VN and remember n is + + align:start position:0% +VN minus one and VN and remember n is + + + align:start position:0% +VN minus one and VN and remember n is +even + + align:start position:0% +even + + + align:start position:0% +even +right so you got to Pick n n/2 coins uh + + align:start position:0% +right so you got to Pick n n/2 coins uh + + + align:start position:0% +right so you got to Pick n n/2 coins uh +if you're the first player and n/ two if + + align:start position:0% +if you're the first player and n/ two if + + + align:start position:0% +if you're the first player and n/ two if +you're the second + + align:start position:0% +you're the second + + + align:start position:0% +you're the second +player um so what the what the first + + align:start position:0% +player um so what the what the first + + + align:start position:0% +player um so what the what the first +player + + align:start position:0% + + + + align:start position:0% + +does um is simply + + align:start position:0% +does um is simply + + + align:start position:0% +does um is simply +compute V1 take the odd numbers and uh n + + align:start position:0% +compute V1 take the odd numbers and uh n + + + align:start position:0% +compute V1 take the odd numbers and uh n +is even so you got VN minus1 being odd + + align:start position:0% +is even so you got VN minus1 being odd + + + align:start position:0% +is even so you got VN minus1 being odd +compute V1 + V3 all the way to VN minus + + align:start position:0% +compute V1 + V3 all the way to VN minus + + + align:start position:0% +compute V1 + V3 all the way to VN minus +one and compare + + align:start position:0% +one and compare + + + align:start position:0% +one and compare +that with uh the even positions V2 plus + + align:start position:0% +that with uh the even positions V2 plus + + + align:start position:0% +that with uh the even positions V2 plus +V4 all the way to VN so in this + + align:start position:0% +V4 all the way to VN so in this + + + align:start position:0% +V4 all the way to VN so in this +particular instance + + align:start position:0% +particular instance + + + align:start position:0% +particular instance +um uh Josiah who went second uh uh but + + align:start position:0% +um uh Josiah who went second uh uh but + + + align:start position:0% +um uh Josiah who went second uh uh but +if you just if you just look at the odd + + align:start position:0% +if you just if you just look at the odd + + + align:start position:0% +if you just if you just look at the odd +positions which is in fact what he ended + + align:start position:0% +positions which is in fact what he ended + + + align:start position:0% +positions which is in fact what he ended +up picking it was 4 + 39 plus 25 which + + align:start position:0% +up picking it was 4 + 39 plus 25 which + + + align:start position:0% +up picking it was 4 + 39 plus 25 which +was 68 and so you can do this + + align:start position:0% +was 68 and so you can do this + + + align:start position:0% +was 68 and so you can do this +computation beforehand you compute this + + align:start position:0% +computation beforehand you compute this + + + align:start position:0% +computation beforehand you compute this +to be 68 in our case compare that with + + align:start position:0% +to be 68 in our case compare that with + + + align:start position:0% +to be 68 in our case compare that with +um + + align:start position:0% +um + + + align:start position:0% +um +67 okay and uh you don't give up your + + align:start position:0% +67 okay and uh you don't give up your + + + align:start position:0% +67 okay and uh you don't give up your +your uh your first player Advantage so + + align:start position:0% +your uh your first player Advantage so + + + align:start position:0% +your uh your first player Advantage so +you're going with the first player but + + align:start position:0% +you're going with the first player but + + + align:start position:0% +you're going with the first player but +now you say I know that I can set this + + align:start position:0% +now you say I know that I can set this + + + align:start position:0% +now you say I know that I can set this +up and that wasn't the order that he did + + align:start position:0% +up and that wasn't the order that he did + + + align:start position:0% +up and that wasn't the order that he did +this but I know I can set this up so I I + + align:start position:0% +this but I know I can set this up so I I + + + align:start position:0% +this but I know I can set this up so I I +always have a chance to get V1 V3 V5 Etc + + align:start position:0% +always have a chance to get V1 V3 V5 Etc + + + align:start position:0% +always have a chance to get V1 V3 V5 Etc +because let's just say that uh uh the + + align:start position:0% +because let's just say that uh uh the + + + align:start position:0% +because let's just say that uh uh the +first player Josiah started first and he + + align:start position:0% +first player Josiah started first and he + + + align:start position:0% +first player Josiah started first and he +decided in this case that the odd values + + align:start position:0% +decided in this case that the odd values + + + align:start position:0% +decided in this case that the odd values +are the ones that win right so you'll + + align:start position:0% +are the ones that win right so you'll + + + align:start position:0% +are the ones that win right so you'll +pick he he pick let's say he picks V1 uh + + align:start position:0% +pick he he pick let's say he picks V1 uh + + + align:start position:0% +pick he he pick let's say he picks V1 uh +at this point Tessa sees V2 through VN + + align:start position:0% +at this point Tessa sees V2 through VN + + + align:start position:0% +at this point Tessa sees V2 through VN +right so he's just looking at to that + + align:start position:0% +right so he's just looking at to that + + + align:start position:0% +right so he's just looking at to that +now Tessa could either pick V2 or she + + align:start position:0% +now Tessa could either pick V2 or she + + + align:start position:0% +now Tessa could either pick V2 or she +could pick VN in that case uh jiia who's + + align:start position:0% +could pick VN in that case uh jiia who's + + + align:start position:0% +could pick VN in that case uh jiia who's +the first player could pick V3 or VN + + align:start position:0% +the first player could pick V3 or VN + + + align:start position:0% +the first player could pick V3 or VN +minus one and stick with his rule of + + align:start position:0% +minus one and stick with his rule of + + + align:start position:0% +minus one and stick with his rule of +picking the odd coins all right so + + align:start position:0% +picking the odd coins all right so + + + align:start position:0% +picking the odd coins all right so +regardless of what Tessa does I the + + align:start position:0% +regardless of what Tessa does I the + + + align:start position:0% +regardless of what Tessa does I the +first + + align:start position:0% +first + + + align:start position:0% +first +player jessiah could pick odd if odd was + + align:start position:0% +player jessiah could pick odd if odd was + + + align:start position:0% +player jessiah could pick odd if odd was +the way to go or if the values were such + + align:start position:0% +the way to go or if the values were such + + + align:start position:0% +the way to go or if the values were such +that even were were the way to go he + + align:start position:0% +that even were were the way to go he + + + align:start position:0% +that even were were the way to go he +could go even okay so no reason for the + + align:start position:0% +could go even okay so no reason for the + + + align:start position:0% +could go even okay so no reason for the +first player to lose uh but uh let's + + align:start position:0% +first player to lose uh but uh let's + + + align:start position:0% +first player to lose uh but uh let's +just say that um you're a nasty person + + align:start position:0% +just say that um you're a nasty person + + + align:start position:0% +just say that um you're a nasty person +right Michael Jordan + + align:start position:0% +right Michael Jordan + + + align:start position:0% +right Michael Jordan +nasty you want to just crush your + + align:start position:0% +nasty you want to just crush your + + + align:start position:0% +nasty you want to just crush your +opponent you you want to make sure they + + align:start position:0% +opponent you you want to make sure they + + + align:start position:0% +opponent you you want to make sure they +never want to play you again okay so now + + align:start position:0% +never want to play you again okay so now + + + align:start position:0% +never want to play you again okay so now +you have a a a a maximization problem + + align:start position:0% +you have a a a a maximization problem + + + align:start position:0% +you have a a a a maximization problem +right so this is clearly not DP you + + align:start position:0% +right so this is clearly not DP you + + + align:start position:0% +right so this is clearly not DP you +don't need DP to add up a bunch of + + align:start position:0% +don't need DP to add up a bunch of + + + align:start position:0% +don't need DP to add up a bunch of +numbers uh but let's say that you want + + align:start position:0% +numbers uh but let's say that you want + + + align:start position:0% +numbers uh but let's say that you want +to given a set of coins V1 through uh VN + + align:start position:0% +to given a set of coins V1 through uh VN + + + align:start position:0% +to given a set of coins V1 through uh VN +uh you want a strategy a dynamic + + align:start position:0% +uh you want a strategy a dynamic + + + align:start position:0% +uh you want a strategy a dynamic +strategy that U uh gives you the maximum + + align:start position:0% +strategy that U uh gives you the maximum + + + align:start position:0% +strategy that U uh gives you the maximum +value right um this odd versus even is a + + align:start position:0% +value right um this odd versus even is a + + + align:start position:0% +value right um this odd versus even is a +bit constraining because you're stuck to + + align:start position:0% +bit constraining because you're stuck to + + + align:start position:0% +bit constraining because you're stuck to +these positions and it's good to be uh + + align:start position:0% +these positions and it's good to be uh + + + align:start position:0% +these positions and it's good to be uh +in that situation if you just want to + + align:start position:0% +in that situation if you just want to + + + align:start position:0% +in that situation if you just want to +win and you don't care how you win right + + align:start position:0% +win and you don't care how you win right + + + align:start position:0% +win and you don't care how you win right +but if you want to maximize then it's a + + align:start position:0% +but if you want to maximize then it's a + + + align:start position:0% +but if you want to maximize then it's a +more complicated problem right and so we + + align:start position:0% +more complicated problem right and so we + + + align:start position:0% +more complicated problem right and so we +have to talk about how you would do uh + + align:start position:0% +have to talk about how you would do uh + + + align:start position:0% +have to talk about how you would do uh +something that would uh give maybe it + + align:start position:0% +something that would uh give maybe it + + + align:start position:0% +something that would uh give maybe it +would be V1 and V4 and something else + + align:start position:0% +would be V1 and V4 and something else + + + align:start position:0% +would be V1 and V4 and something else +depends on the values how would you get + + align:start position:0% +depends on the values how would you get + + + align:start position:0% +depends on the values how would you get +to a situation if you're the first + + align:start position:0% +to a situation if you're the first + + + align:start position:0% +to a situation if you're the first +player we just stick with you're the + + align:start position:0% +player we just stick with you're the + + + align:start position:0% +player we just stick with you're the +first player you know you can't lose + + align:start position:0% +first player you know you can't lose + + + align:start position:0% +first player you know you can't lose +using this strategy but not only do you + + align:start position:0% +using this strategy but not only do you + + + align:start position:0% +using this strategy but not only do you +want to not lose you want to get as many + + align:start position:0% +want to not lose you want to get as many + + + align:start position:0% +want to not lose you want to get as many +coins as possible let's say this is + + align:start position:0% +coins as possible let's say this is + + + align:start position:0% +coins as possible let's say this is +money you know more money is better uh + + align:start position:0% +money you know more money is better uh + + + align:start position:0% +money you know more money is better uh +and uh that's your goal okay so uh so + + align:start position:0% +and uh that's your goal okay so uh so + + + align:start position:0% +and uh that's your goal okay so uh so +people understand that a little + + align:start position:0% +people understand that a little + + + align:start position:0% +people understand that a little +U little trick there with a I guess a + + align:start position:0% +U little trick there with a I guess a + + + align:start position:0% +U little trick there with a I guess a +greedy algorithm you can you can think + + align:start position:0% +greedy algorithm you can you can think + + + align:start position:0% +greedy algorithm you can you can think +of + + align:start position:0% +of + + + align:start position:0% +of +or it's not really a even something that + + align:start position:0% +or it's not really a even something that + + + align:start position:0% +or it's not really a even something that +you might want to call an algorithm + + align:start position:0% +you might want to call an algorithm + + + align:start position:0% +you might want to call an algorithm +little + + align:start position:0% +little + + + align:start position:0% +little +computation and our goal now is to + + align:start position:0% + + + + align:start position:0% + +maximize the amount of + + align:start position:0% + + + + align:start position:0% + +money when + + align:start position:0% + + + + align:start position:0% + +assuming you move + + align:start position:0% +assuming you move + + + align:start position:0% +assuming you move +first and so this is going to be a + + align:start position:0% +first and so this is going to be a + + + align:start position:0% +first and so this is going to be a +little bit different uh from all of the + + align:start position:0% +little bit different uh from all of the + + + align:start position:0% +little bit different uh from all of the +other problems we looked at because we + + align:start position:0% +other problems we looked at because we + + + align:start position:0% +other problems we looked at because we +have to now think about what the + + align:start position:0% +have to now think about what the + + + align:start position:0% +have to now think about what the +opponent would do right and there's + + align:start position:0% +opponent would do right and there's + + + align:start position:0% +opponent would do right and there's +going to be a sequence of moves here + + align:start position:0% +going to be a sequence of moves here + + + align:start position:0% +going to be a sequence of moves here +right you're going to move first so that + + align:start position:0% +right you're going to move first so that + + + align:start position:0% +right you're going to move first so that +one is easy you got the whole problem uh + + align:start position:0% +one is easy you got the whole problem uh + + + align:start position:0% +one is easy you got the whole problem uh +but now you have to say um the opponent + + align:start position:0% +but now you have to say um the opponent + + + align:start position:0% +but now you have to say um the opponent +is going to move uh and pick a coin and + + align:start position:0% +is going to move uh and pick a coin and + + + align:start position:0% +is going to move uh and pick a coin and +then you have to think of your sub + + align:start position:0% +then you have to think of your sub + + + align:start position:0% +then you have to think of your sub +problems as the potential uh rows of + + align:start position:0% +problems as the potential uh rows of + + + align:start position:0% +problems as the potential uh rows of +coins that are going to be different + + align:start position:0% +coins that are going to be different + + + align:start position:0% +coins that are going to be different +depending on what the opponent does + + align:start position:0% +depending on what the opponent does + + + align:start position:0% +depending on what the opponent does +right and through this process you have + + align:start position:0% +right and through this process you have + + + align:start position:0% +right and through this process you have +to maximize the value right so it's a + + align:start position:0% +to maximize the value right so it's a + + + align:start position:0% +to maximize the value right so it's a +it's really pretty different from the + + align:start position:0% +it's really pretty different from the + + + align:start position:0% +it's really pretty different from the +other couple of examples that uh that we + + align:start position:0% +other couple of examples that uh that we + + + align:start position:0% +other couple of examples that uh that we +looked + + align:start position:0% +looked + + + align:start position:0% +looked +at um so we're going to have to do a + + align:start position:0% +at um so we're going to have to do a + + + align:start position:0% +at um so we're going to have to do a +little bit of setup before we get to the + + align:start position:0% +little bit of setup before we get to the + + + align:start position:0% +little bit of setup before we get to the +point where we can write something like + + align:start position:0% +point where we can write something like + + + align:start position:0% +point where we can write something like +this which is uh the solution to our to + + align:start position:0% +this which is uh the solution to our to + + + align:start position:0% +this which is uh the solution to our to +our DP and so let me do that set up but + + align:start position:0% +our DP and so let me do that set up but + + + align:start position:0% +our DP and so let me do that set up but +it's not super complicated and part of + + align:start position:0% +it's not super complicated and part of + + + align:start position:0% +it's not super complicated and part of +this is going to look kind of the same + + align:start position:0% +this is going to look kind of the same + + + align:start position:0% +this is going to look kind of the same +as previous problems we've looked at um + + align:start position:0% +as previous problems we've looked at um + + + align:start position:0% +as previous problems we've looked at um +so VI J is the max value + + align:start position:0% +so VI J is the max value + + + align:start position:0% +so VI J is the max value +we + + align:start position:0% +we + + + align:start position:0% +we +can definitely + + align:start position:0% + + + + align:start position:0% + +win + + align:start position:0% +win + + + align:start position:0% +win +if it is our + + align:start position:0% + + + + align:start position:0% + +turn and only + + align:start position:0% +turn and only + + + align:start position:0% +turn and only +coins VI through VJ I + + align:start position:0% +coins VI through VJ I + + + align:start position:0% +coins VI through VJ I +remain + + align:start position:0% + + + + align:start position:0% + +okay and so we have VI I + + align:start position:0% +okay and so we have VI I + + + align:start position:0% +okay and so we have VI I +then there's only one coin + + align:start position:0% +then there's only one coin + + + align:start position:0% +then there's only one coin +left and you just pick + + align:start position:0% +left and you just pick + + + align:start position:0% +left and you just pick +I right now uh you need this you might + + align:start position:0% +I right now uh you need this you might + + + align:start position:0% +I right now uh you need this you might +say well but that's never going to + + align:start position:0% +say well but that's never going to + + + align:start position:0% +say well but that's never going to +happen uh if there's an even number of + + align:start position:0% +happen uh if there's an even number of + + + align:start position:0% +happen uh if there's an even number of +coins and I'm playing first uh because + + align:start position:0% +coins and I'm playing first uh because + + + align:start position:0% +coins and I'm playing first uh because +the other uh player is going to be at + + align:start position:0% +the other uh player is going to be at + + + align:start position:0% +the other uh player is going to be at +the end of the the the the is going to + + align:start position:0% +the end of the the the the is going to + + + align:start position:0% +the end of the the the the is going to +be the person who picks the last coin + + align:start position:0% +be the person who picks the last coin + + + align:start position:0% +be the person who picks the last coin +but we need to characterize VII is + + align:start position:0% +but we need to characterize VII is + + + align:start position:0% +but we need to characterize VII is +because we need to model what the other + + align:start position:0% +because we need to model what the other + + + align:start position:0% +because we need to model what the other +players going to do right so we can't + + align:start position:0% +players going to do right so we can't + + + align:start position:0% +players going to do right so we can't +just say that we're going to be looking + + align:start position:0% +just say that we're going to be looking + + + align:start position:0% +just say that we're going to be looking +at even number of coins in terms of the + + align:start position:0% +at even number of coins in terms of the + + + align:start position:0% +at even number of coins in terms of the +row of coins that uh you you look at + + align:start position:0% +row of coins that uh you you look at + + + align:start position:0% +row of coins that uh you you look at +which is true that when you get to move + + align:start position:0% +which is true that when you get to move + + + align:start position:0% +which is true that when you get to move +you only see an even number of coins if + + align:start position:0% +you only see an even number of coins if + + + align:start position:0% +you only see an even number of coins if +you're the first player but you do have + + align:start position:0% +you're the first player but you do have + + + align:start position:0% +you're the first player but you do have +to model what the opponent does so we + + align:start position:0% +to model what the opponent does so we + + + align:start position:0% +to model what the opponent does so we +need the VII + + align:start position:0% +need the VII + + + align:start position:0% +need the VII +okay um and what you you might see of + + align:start position:0% +okay um and what you you might see of + + + align:start position:0% +okay um and what you you might see of +course uh is a board that looks like VI + + align:start position:0% +course uh is a board that looks like VI + + + align:start position:0% +course uh is a board that looks like VI +I + + + align:start position:0% +I + + + + align:start position:0% +I + +one uh and I mean it might um + + align:start position:0% +one uh and I mean it might um + + + align:start position:0% +one uh and I mean it might um +be for some arbitrary eye right so + + align:start position:0% +be for some arbitrary eye right so + + + align:start position:0% +be for some arbitrary eye right so +that's why I have it up there but + + align:start position:0% +that's why I have it up there but + + + align:start position:0% +that's why I have it up there but +remember that you're only picking coins + + align:start position:0% +remember that you're only picking coins + + + align:start position:0% +remember that you're only picking coins +on the outside so it's not like you're + + align:start position:0% +on the outside so it's not like you're + + + align:start position:0% +on the outside so it's not like you're +going to have a gap Ian you're not going + + align:start position:0% +going to have a gap Ian you're not going + + + align:start position:0% +going to have a gap Ian you're not going +to have V3 left and V7 left right + + align:start position:0% +to have V3 left and V7 left right + + + align:start position:0% +to have V3 left and V7 left right +there's no way that's going to happen + + align:start position:0% +there's no way that's going to happen + + + align:start position:0% +there's no way that's going to happen +you're just going to keep shrinking + + align:start position:0% +you're just going to keep shrinking + + + align:start position:0% +you're just going to keep shrinking +taking things from the left or the right + + align:start position:0% +taking things from the left or the right + + + align:start position:0% +taking things from the left or the right +right so it's going to be I and I + one + + align:start position:0% +right so it's going to be I and I + one + + + align:start position:0% +right so it's going to be I and I + one +right that Mak sense um and so in this + + align:start position:0% +right that Mak sense um and so in this + + + align:start position:0% +right that Mak sense um and so in this +case what would you pick VI and I + + + align:start position:0% +case what would you pick VI and I + + + + align:start position:0% +case what would you pick VI and I + +one you just pick the max right because + + align:start position:0% +one you just pick the max right because + + + align:start position:0% +one you just pick the max right because +that end of this either you did it right + + align:start position:0% +that end of this either you did it right + + + align:start position:0% +that end of this either you did it right +or you did it wrong either way you're + + align:start position:0% +or you did it wrong either way you're + + + align:start position:0% +or you did it wrong either way you're +going to improve your situation by + + align:start position:0% +going to improve your situation by + + + align:start position:0% +going to improve your situation by +picking the max of VI or VI + 1 right so + + align:start position:0% +picking the max of VI or VI + 1 right so + + + align:start position:0% +picking the max of VI or VI + 1 right so +there's no two things about it so here + + align:start position:0% +there's no two things about it so here + + + align:start position:0% +there's no two things about it so here +you're going to + + align:start position:0% + + + + align:start position:0% + +pick the + + align:start position:0% + + + + align:start position:0% + +maximum of the + + align:start position:0% + + + + align:start position:0% + +two um and you might have U VI i+ plus + + align:start position:0% +two um and you might have U VI i+ plus + + + align:start position:0% +two um and you might have U VI i+ plus +two which is an an odd number of coins + + align:start position:0% +two which is an an odd number of coins + + + align:start position:0% +two which is an an odd number of coins +that um that your opponent might see uh + + align:start position:0% +that um that your opponent might see uh + + + align:start position:0% +that um that your opponent might see uh +it gets more complicated uh for Vi and + + align:start position:0% +it gets more complicated uh for Vi and + + + align:start position:0% +it gets more complicated uh for Vi and +i+ 2 we're going to have to uh now start + + align:start position:0% +i+ 2 we're going to have to uh now start + + + align:start position:0% +i+ 2 we're going to have to uh now start +thinking in more general terms as to + + align:start position:0% +thinking in more general terms as to + + + align:start position:0% +thinking in more general terms as to +what the different moves are right but + + align:start position:0% +what the different moves are right but + + + align:start position:0% +what the different moves are right but +we got the base cases here all I did + + align:start position:0% +we got the base cases here all I did + + + align:start position:0% +we got the base cases here all I did +here was take care of the base case or a + + align:start position:0% +here was take care of the base case or a + + + align:start position:0% +here was take care of the base case or a +couple of Base cases associated with um + + align:start position:0% +couple of Base cases associated with um + + + align:start position:0% +couple of Base cases associated with um +a single coin which is what your + + align:start position:0% +a single coin which is what your + + + align:start position:0% +a single coin which is what your +opponent will see and pick or two coins + + align:start position:0% +opponent will see and pick or two coins + + + align:start position:0% +opponent will see and pick or two coins +which is your last move + + align:start position:0% +which is your last move + + + align:start position:0% +which is your last move +okay so with all with DP of course you + + align:start position:0% +okay so with all with DP of course you + + + align:start position:0% +okay so with all with DP of course you +always have to go down to your base case + + align:start position:0% +always have to go down to your base case + + + align:start position:0% +always have to go down to your base case +right and that's when things become + + align:start position:0% +right and that's when things become + + + align:start position:0% +right and that's when things become +easy um so let's talk about we have to + + align:start position:0% +easy um so let's talk about we have to + + + align:start position:0% +easy um so let's talk about we have to +talk about two things and put U our + + align:start position:0% +talk about two things and put U our + + + align:start position:0% +talk about two things and put U our +recurrence + + align:start position:0% +recurrence + + + align:start position:0% +recurrence +together the two things we have to talk + + align:start position:0% +together the two things we have to talk + + + align:start position:0% +together the two things we have to talk +about are what you do when you + + align:start position:0% +about are what you do when you + + + align:start position:0% +about are what you do when you +move um and that's actually fairly easy + + align:start position:0% +move um and that's actually fairly easy + + + align:start position:0% +move um and that's actually fairly easy +and the second thing is what uh the + + align:start position:0% +and the second thing is what uh the + + + align:start position:0% +and the second thing is what uh the +model of the opponent looks like uh when + + align:start position:0% +model of the opponent looks like uh when + + + align:start position:0% +model of the opponent looks like uh when +uh you're waiting for um uh him or her + + align:start position:0% +uh you're waiting for um uh him or her + + + align:start position:0% +uh you're waiting for um uh him or her +to move so let's take a look at your + + align:start position:0% +to move so let's take a look at your + + + align:start position:0% +to move so let's take a look at your +move and I got + + align:start position:0% +move and I got + + + align:start position:0% +move and I got +V1 let's look at + + align:start position:0% + + + + align:start position:0% + +VI let say VJ here dot do dot VN right + + align:start position:0% +VI let say VJ here dot do dot VN right + + + align:start position:0% +VI let say VJ here dot do dot VN right +so that's the the what you see uh and + + align:start position:0% +so that's the the what you see uh and + + + align:start position:0% +so that's the the what you see uh and +you're looking at I and + + align:start position:0% +you're looking at I and + + + align:start position:0% +you're looking at I and +J and at this point you're you're seeing + + align:start position:0% +J and at this point you're you're seeing + + + align:start position:0% +J and at this point you're you're seeing +all those other coins the outer coins + + align:start position:0% +all those other coins the outer coins + + + align:start position:0% +all those other coins the outer coins +have disappeared + + align:start position:0% +have disappeared + + + align:start position:0% +have disappeared +uh into people's pockets uh and you're + + align:start position:0% +uh into people's pockets uh and you're + + + align:start position:0% +uh into people's pockets uh and you're +looking at this uh + + align:start position:0% +looking at this uh + + + align:start position:0% +looking at this uh +interval so I'm going to write out what + + align:start position:0% +interval so I'm going to write out what + + + align:start position:0% +interval so I'm going to write out what +VI should be and keep in mind that we + + align:start position:0% +VI should be and keep in mind that we + + + align:start position:0% +VI should be and keep in mind that we +want to um uh maximize the amount of + + align:start position:0% +want to um uh maximize the amount of + + + align:start position:0% +want to um uh maximize the amount of +money and we want to say that we should + + align:start position:0% +money and we want to say that we should + + + align:start position:0% +money and we want to say that we should +be able to definitely win this amount of + + align:start position:0% +be able to definitely win this amount of + + + align:start position:0% +be able to definitely win this amount of +money right regardless of what the + + align:start position:0% +money right regardless of what the + + + align:start position:0% +money right regardless of what the +opponent + + align:start position:0% +opponent + + + align:start position:0% +opponent +does so um I want to do a a Max + + align:start position:0% +does so um I want to do a a Max + + + align:start position:0% +does so um I want to do a a Max +obviously + + align:start position:0% + + + + align:start position:0% + +and um I have two choices here I can + + align:start position:0% +and um I have two choices here I can + + + align:start position:0% +and um I have two choices here I can +pick VI or I can pick VJ right so it's + + align:start position:0% +pick VI or I can pick VJ right so it's + + + align:start position:0% +pick VI or I can pick VJ right so it's +not like there's a lot of choices here + + align:start position:0% +not like there's a lot of choices here + + + align:start position:0% +not like there's a lot of choices here +right so if I pick VI uh then let me go + + align:start position:0% +right so if I pick VI uh then let me go + + + align:start position:0% +right so if I pick VI uh then let me go +ahead and say I pick VI + + align:start position:0% +ahead and say I pick VI + + + align:start position:0% +ahead and say I pick VI +here and here I'd pick + + align:start position:0% + + + + align:start position:0% + +VJ and uh whoops let me draw this a + + align:start position:0% +VJ and uh whoops let me draw this a + + + align:start position:0% +VJ and uh whoops let me draw this a +little bit + + align:start position:0% +little bit + + + align:start position:0% +little bit +better so I got to fill in uh these two + + align:start position:0% +better so I got to fill in uh these two + + + align:start position:0% +better so I got to fill in uh these two +uh uh arguments + + align:start position:0% +uh uh arguments + + + align:start position:0% +uh uh arguments +to to my + + align:start position:0% +to to my + + + align:start position:0% +to to my +Max right so um this is + + align:start position:0% +Max right so um this is + + + align:start position:0% +Max right so um this is +easy I'm going to have a plus VI here + + align:start position:0% +easy I'm going to have a plus VI here + + + align:start position:0% +easy I'm going to have a plus VI here +going to have a plus VJ + + align:start position:0% +going to have a plus VJ + + + align:start position:0% +going to have a plus VJ +here right so because I picked the + + align:start position:0% +here right so because I picked the + + + align:start position:0% +here right so because I picked the +appropriate value um and um now this is + + align:start position:0% +appropriate value um and um now this is + + + align:start position:0% +appropriate value um and um now this is +also not that uh difficult uh what + + align:start position:0% +also not that uh difficult uh what + + + align:start position:0% +also not that uh difficult uh what +exactly happens what can I put in + + align:start position:0% +exactly happens what can I put in + + + align:start position:0% +exactly happens what can I put in +here if I pick + + align:start position:0% +here if I pick + + + align:start position:0% +here if I pick +VI yeah VI + one to J so the range + + align:start position:0% +VI yeah VI + one to J so the range + + + align:start position:0% +VI yeah VI + one to J so the range +becomes + + align:start position:0% +becomes + + + align:start position:0% +becomes +uh I + 1 J so I got uh uh I I have to be + + align:start position:0% +uh I + 1 J so I got uh uh I I have to be + + + align:start position:0% +uh I + 1 J so I got uh uh I I have to be +a little careful here in terms of uh uh + + align:start position:0% +a little careful here in terms of uh uh + + + align:start position:0% +a little careful here in terms of uh uh +whether um I can argue that it's + + align:start position:0% +whether um I can argue that it's + + + align:start position:0% +whether um I can argue that it's +actually the V that I put in here so the + + align:start position:0% +actually the V that I put in here so the + + + align:start position:0% +actually the V that I put in here so the +subtlety here is simply that uh uh that + + align:start position:0% +subtlety here is simply that uh uh that + + + align:start position:0% +subtlety here is simply that uh uh that +the the + + align:start position:0% +the the + + + align:start position:0% +the the +vi + one J is not something that I see + + align:start position:0% +vi + one J is not something that I see + + + align:start position:0% +vi + one J is not something that I see +in front of me + + align:start position:0% +in front of me + + + align:start position:0% +in front of me +okay this is the complication VI + 1j is + + align:start position:0% +okay this is the complication VI + 1j is + + + align:start position:0% +okay this is the complication VI + 1j is +never a board that I see in front of me + + align:start position:0% +never a board that I see in front of me + + + align:start position:0% +never a board that I see in front of me +whereas VI was a board that I saw in + + align:start position:0% +whereas VI was a board that I saw in + + + align:start position:0% +whereas VI was a board that I saw in +front of me right so I have to model uh + + align:start position:0% +front of me right so I have to model uh + + + align:start position:0% +front of me right so I have to model uh +the the boards that I see in front of me + + align:start position:0% +the the boards that I see in front of me + + + align:start position:0% +the the boards that I see in front of me +because those are the boards that I have + + align:start position:0% +because those are the boards that I have + + + align:start position:0% +because those are the boards that I have +control over that I can maximize right I + + align:start position:0% +control over that I can maximize right I + + + align:start position:0% +control over that I can maximize right I +the the I need I cannot put vij vi+ 1j + + align:start position:0% +the the I need I cannot put vij vi+ 1j + + + align:start position:0% +the the I need I cannot put vij vi+ 1j +in there simply because I I don't quite + + align:start position:0% +in there simply because I I don't quite + + + align:start position:0% +in there simply because I I don't quite +know what that is because I what I get + + align:start position:0% +know what that is because I what I get + + + align:start position:0% +know what that is because I what I get +eventually is not something I control + + align:start position:0% +eventually is not something I control + + + align:start position:0% +eventually is not something I control +right it's going to be the the the board + + align:start position:0% +right it's going to be the the the board + + + align:start position:0% +right it's going to be the the the board +after my opponent has moved all right so + + align:start position:0% +after my opponent has moved all right so + + + align:start position:0% +after my opponent has moved all right so +all I'm going to do is I'm going to say + + align:start position:0% +all I'm going to do is I'm going to say + + + align:start position:0% +all I'm going to do is I'm going to say +the + + align:start position:0% +the + + + align:start position:0% +the +range um + + align:start position:0% +range um + + + align:start position:0% +range um +becomes range + + align:start position:0% +becomes range + + + align:start position:0% +becomes range +is um I + 1 + + align:start position:0% + + + + align:start position:0% + +J um and I'm going to say something else + + align:start position:0% +J um and I'm going to say something else + + + align:start position:0% +J um and I'm going to say something else +in a second here the range is uh + + align:start position:0% +in a second here the range is uh + + + align:start position:0% +in a second here the range is uh +i j minus + + align:start position:0% +i j minus + + + align:start position:0% +i j minus +one okay and in both of these + + align:start position:0% +one okay and in both of these + + + align:start position:0% +one okay and in both of these +cases the opponent + + align:start position:0% + + + + align:start position:0% + +moves so in order to actually write out + + align:start position:0% +moves so in order to actually write out + + + align:start position:0% +moves so in order to actually write out +my DP I'm going to have to now U look at + + align:start position:0% +my DP I'm going to have to now U look at + + + align:start position:0% +my DP I'm going to have to now U look at +the worst case + + align:start position:0% +the worst case + + + align:start position:0% +the worst case +situation in terms of the board I get + + align:start position:0% +situation in terms of the board I get + + + align:start position:0% +situation in terms of the board I get +back because the only times I'm adding + + align:start position:0% +back because the only times I'm adding + + + align:start position:0% +back because the only times I'm adding +values is when I see a board in front of + + align:start position:0% +values is when I see a board in front of + + + align:start position:0% +values is when I see a board in front of +me and pick a coin and I'm going to have + + align:start position:0% +me and pick a coin and I'm going to have + + + align:start position:0% +me and pick a coin and I'm going to have +to say now the opponent is going to see + + align:start position:0% +to say now the opponent is going to see + + + align:start position:0% +to say now the opponent is going to see +an i + 1 + + align:start position:0% +an i + 1 + + + align:start position:0% +an i + 1 +J and or or an i minus one i j minus one + + align:start position:0% +J and or or an i minus one i j minus one + + + align:start position:0% +J and or or an i minus one i j minus one +excuse me and might do something and I'm + + align:start position:0% +excuse me and might do something and I'm + + + align:start position:0% +excuse me and might do something and I'm +going to get something back let's assume + + align:start position:0% +going to get something back let's assume + + + align:start position:0% +going to get something back let's assume +that I I'm going to assume that the + + align:start position:0% +that I I'm going to assume that the + + + align:start position:0% +that I I'm going to assume that the +opponent is just as smart as I am knows + + align:start position:0% +opponent is just as smart as I am knows + + + align:start position:0% +opponent is just as smart as I am knows +DP taking 6046 etc etc and uh I still + + align:start position:0% +DP taking 6046 etc etc and uh I still + + + align:start position:0% +DP taking 6046 etc etc and uh I still +want to get the maximum value that I can + + align:start position:0% +want to get the maximum value that I can + + + align:start position:0% +want to get the maximum value that I can +definitely win okay um and so uh we need + + align:start position:0% +definitely win okay um and so uh we need + + + align:start position:0% +definitely win okay um and so uh we need +to look inside of that a little bit and + + align:start position:0% +to look inside of that a little bit and + + + align:start position:0% +to look inside of that a little bit and +it's not that hard if you just make the + + align:start position:0% +it's not that hard if you just make the + + + align:start position:0% +it's not that hard if you just make the +assumption that I just did which is uh + + align:start position:0% +assumption that I just did which is uh + + + align:start position:0% +assumption that I just did which is uh +the opponent um is going + + align:start position:0% +the opponent um is going + + + align:start position:0% +the opponent um is going +to uh I mean might not necessarily do + + align:start position:0% +to uh I mean might not necessarily do + + + align:start position:0% +to uh I mean might not necessarily do +the right thing but you have to assume + + align:start position:0% +the right thing but you have to assume + + + align:start position:0% +the right thing but you have to assume +that uh the opponent knows it just as + + align:start position:0% +that uh the opponent knows it just as + + + align:start position:0% +that uh the opponent knows it just as +much as you do and is going to try and + + align:start position:0% +much as you do and is going to try and + + + align:start position:0% +much as you do and is going to try and +um uh uh do as well as possible okay so + + align:start position:0% +um uh uh do as well as possible okay so + + + align:start position:0% +um uh uh do as well as possible okay so +uh let's do that that's the last thing + + align:start position:0% +uh let's do that that's the last thing + + + align:start position:0% +uh let's do that that's the last thing +that we have to do here and uh it's just + + align:start position:0% +that we have to do here and uh it's just + + + align:start position:0% +that we have to do here and uh it's just +one uh more equation so so here's the + + align:start position:0% +one uh more equation so so here's the + + + align:start position:0% +one uh more equation so so here's the +solution we now have a v i + 1 J sub + + align:start position:0% + + + + align:start position:0% + +problem with the opponent + + align:start position:0% + + + + align:start position:0% + +picking + + align:start position:0% +picking + + + align:start position:0% +picking +and um the simple observation is that we + + align:start position:0% +and um the simple observation is that we + + + align:start position:0% +and um the simple observation is that we +are + + align:start position:0% + + + + align:start position:0% + +guaranteed the + + align:start position:0% +guaranteed the + + + align:start position:0% +guaranteed the +men of v i + 1 Jus + + align:start position:0% +men of v i + 1 Jus + + + align:start position:0% +men of v i + 1 Jus +1 or v i + 2 + + align:start position:0% +1 or v i + 2 + + + align:start position:0% +1 or v i + 2 +J in this + + align:start position:0% +J in this + + + align:start position:0% +J in this +case um the opponent + + align:start position:0% + + + + align:start position:0% + +picks VJ and in this case the opponent + + align:start position:0% + + + + align:start position:0% + +picks VI + + + align:start position:0% +picks VI + + + + align:start position:0% +picks VI + +1 right and you're you're guaranteed the + + align:start position:0% +1 right and you're you're guaranteed the + + + align:start position:0% +1 right and you're you're guaranteed the +minimum of these two because the + + align:start position:0% +minimum of these two because the + + + align:start position:0% +minimum of these two because the +opponent can only pick one coin right so + + align:start position:0% +opponent can only pick one coin right so + + + align:start position:0% +opponent can only pick one coin right so +that's the the simple observation that + + align:start position:0% +that's the the simple observation that + + + align:start position:0% +that's the the simple observation that +lets you jump + + align:start position:0% +lets you jump + + + align:start position:0% +lets you jump +ahead uh to your next move which is + + align:start position:0% +ahead uh to your next move which is + + + align:start position:0% +ahead uh to your next move which is +really what uh the DP is interested in + + align:start position:0% +really what uh the DP is interested in + + + align:start position:0% +really what uh the DP is interested in +uh because uh that's the only time that + + align:start position:0% +uh because uh that's the only time that + + + align:start position:0% +uh because uh that's the only time that +you're actually executing something in + + align:start position:0% +you're actually executing something in + + + align:start position:0% +you're actually executing something in +terms of picking coins from the board + + align:start position:0% +terms of picking coins from the board + + + align:start position:0% +terms of picking coins from the board +and adding to your value right but we + + align:start position:0% +and adding to your value right but we + + + align:start position:0% +and adding to your value right but we +did did have to model that as to what uh + + align:start position:0% +did did have to model that as to what uh + + + align:start position:0% +did did have to model that as to what uh +the maximum value was that you could win + + align:start position:0% +the maximum value was that you could win + + + align:start position:0% +the maximum value was that you could win +uh jumping ahead of this move and you + + align:start position:0% +uh jumping ahead of this move and you + + + align:start position:0% +uh jumping ahead of this move and you +have have the the Min here because + + align:start position:0% +have have the the Min here because + + + align:start position:0% +have have the the Min here because +you're assuming that uh this is a + + align:start position:0% +you're assuming that uh this is a + + + align:start position:0% +you're assuming that uh this is a +definite guarantee right that's what we + + align:start position:0% +definite guarantee right that's what we + + + align:start position:0% +definite guarantee right that's what we +want uh it's possible that uh the + + align:start position:0% +want uh it's possible that uh the + + + align:start position:0% +want uh it's possible that uh the +opponent plays uh um a different game + + align:start position:0% +opponent plays uh um a different game + + + align:start position:0% +opponent plays uh um a different game +from uh the one that um we think he or + + align:start position:0% +from uh the one that um we think he or + + + align:start position:0% +from uh the one that um we think he or +she is going to play which maximizes his + + align:start position:0% +she is going to play which maximizes his + + + align:start position:0% +she is going to play which maximizes his +or her value but the men is a guarantee + + align:start position:0% +or her value but the men is a guarantee + + + align:start position:0% +or her value but the men is a guarantee +okay so now that you've made this + + align:start position:0% +okay so now that you've made this + + + align:start position:0% +okay so now that you've made this +observation uh it turns out we just have + + align:start position:0% +observation uh it turns out we just have + + + align:start position:0% +observation uh it turns out we just have +to take that and uh uh we we we'll we'll + + align:start position:0% +to take that and uh uh we we we'll we'll + + + align:start position:0% +to take that and uh uh we we we'll we'll +be done right so let's see uh let me + + align:start position:0% +be done right so let's see uh let me + + + align:start position:0% +be done right so let's see uh let me +erase this so + + align:start position:0% +erase this so + + + align:start position:0% +erase this so +last set of + + align:start position:0% + + + + align:start position:0% + +equations and it's just plugging in that + + align:start position:0% +equations and it's just plugging in that + + + align:start position:0% +equations and it's just plugging in that +observation into what I wrote + + align:start position:0% +observation into what I wrote + + + align:start position:0% +observation into what I wrote +before so we have V + + align:start position:0% +before so we have V + + + align:start position:0% +before so we have V +J equals Max this is the outer Max that + + align:start position:0% +J equals Max this is the outer Max that + + + align:start position:0% +J equals Max this is the outer Max that +I had up there already so that's the + + align:start position:0% +I had up there already so that's the + + + align:start position:0% +I had up there already so that's the +same + + align:start position:0% +same + + + align:start position:0% +same +Max um and put this giant brackets here + + align:start position:0% + + + + align:start position:0% + +and inside I I'm going to plug in this + + align:start position:0% +and inside I I'm going to plug in this + + + align:start position:0% +and inside I I'm going to plug in this +this + + align:start position:0% +this + + + align:start position:0% +this +minim uh which is something that + + align:start position:0% +minim uh which is something that + + + align:start position:0% +minim uh which is something that +corresponds to the the the value that I + + align:start position:0% +corresponds to the the the value that I + + + align:start position:0% +corresponds to the the the value that I +would win in the worst case after the + + align:start position:0% +would win in the worst case after the + + + align:start position:0% +would win in the worst case after the +opponent plays the best possible move + + align:start position:0% +opponent plays the best possible move + + + align:start position:0% +opponent plays the best possible move +and that would be VI I + + + align:start position:0% +and that would be VI I + + + + align:start position:0% +and that would be VI I + +1 Jus + + align:start position:0% +1 Jus + + + align:start position:0% +1 Jus +one + + align:start position:0% +one + + + align:start position:0% +one +uh + + align:start position:0% +uh + + + align:start position:0% +uh +comma we I + 2 J plus VI this VI is the + + align:start position:0% +comma we I + 2 J plus VI this VI is the + + + align:start position:0% +comma we I + 2 J plus VI this VI is the +same as this one up + + align:start position:0% +same as this one up + + + align:start position:0% +same as this one up +here um and you got a plus VJ here and I + + align:start position:0% +here um and you got a plus VJ here and I + + + align:start position:0% +here um and you got a plus VJ here and I +didn't actually do this but in terms of + + align:start position:0% +didn't actually do this but in terms of + + + align:start position:0% +didn't actually do this but in terms of +writing out what the opponent would do + + align:start position:0% +writing out what the opponent would do + + + align:start position:0% +writing out what the opponent would do +in the other sub problem case but it's + + align:start position:0% +in the other sub problem case but it's + + + align:start position:0% +in the other sub problem case but it's +really pretty straightforward uh you um + + align:start position:0% +really pretty straightforward uh you um + + + align:start position:0% +really pretty straightforward uh you um +have a problem that corresponds to uh + + align:start position:0% +have a problem that corresponds to uh + + + align:start position:0% +have a problem that corresponds to uh +the i j minus one problem and the + + align:start position:0% +the i j minus one problem and the + + + align:start position:0% +the i j minus one problem and the +opponent could pick the I or could pick + + align:start position:0% +opponent could pick the I or could pick + + + align:start position:0% +opponent could pick the I or could pick +the J minus one if the opponent picks + + align:start position:0% +the J minus one if the opponent picks + + + align:start position:0% +the J minus one if the opponent picks +the J minus one you get um v i j minus 2 + + align:start position:0% +the J minus one you get um v i j minus 2 + + + align:start position:0% +the J minus one you get um v i j minus 2 +and you need to take the Min of that and + + align:start position:0% +and you need to take the Min of that and + + + align:start position:0% +and you need to take the Min of that and +the other case where the opponent picks + + align:start position:0% +the other case where the opponent picks + + + align:start position:0% +the other case where the opponent picks +I in which case you get I + 1 J minus + + align:start position:0% +I in which case you get I + 1 J minus + + + align:start position:0% +I in which case you get I + 1 J minus +one + + align:start position:0% +one + + + align:start position:0% +one +okay and that's our DP that's that's R + + align:start position:0% +okay and that's our DP that's that's R + + + align:start position:0% +okay and that's our DP that's that's R +DP okay so the big difference here was + + align:start position:0% +DP okay so the big difference here was + + + align:start position:0% +DP okay so the big difference here was +the modeling that you had to do in the + + align:start position:0% +the modeling that you had to do in the + + + align:start position:0% +the modeling that you had to do in the +middle we didn't actually have to do + + align:start position:0% +middle we didn't actually have to do + + + align:start position:0% +middle we didn't actually have to do +that in any of the DPS we've + + align:start position:0% +that in any of the DPS we've + + + align:start position:0% +that in any of the DPS we've +covered uh in 046 at least uh up until + + align:start position:0% +covered uh in 046 at least uh up until + + + align:start position:0% +covered uh in 046 at least uh up until +this point um before we talk about + + align:start position:0% +this point um before we talk about + + + align:start position:0% +this point um before we talk about +complexity I that should just take a + + align:start position:0% +complexity I that should just take a + + + align:start position:0% +complexity I that should just take a +minute people buy that see that good so + + align:start position:0% +minute people buy that see that good so + + + align:start position:0% +minute people buy that see that good so +uh with all of these problems the + + align:start position:0% +uh with all of these problems the + + + align:start position:0% +uh with all of these problems the +complexities are fairly straightforward + + align:start position:0% +complexities are fairly straightforward + + + align:start position:0% +complexities are fairly straightforward +to compute I the complexity here is + + align:start position:0% +to compute I the complexity here is + + + align:start position:0% +to compute I the complexity here is +simply again as before the number of sub + + align:start position:0% +simply again as before the number of sub + + + align:start position:0% +simply again as before the number of sub +problems times the time it it it takes + + align:start position:0% +problems times the time it it it takes + + + align:start position:0% +problems times the time it it it takes +to solve a sub problem uh you can see + + align:start position:0% +to solve a sub problem uh you can see + + + align:start position:0% +to solve a sub problem uh you can see +here that these are all constant time + + align:start position:0% +here that these are all constant time + + + align:start position:0% +here that these are all constant time +operations so assuming that the the the + + align:start position:0% +operations so assuming that the the the + + + align:start position:0% +operations so assuming that the the the +the vs have been computed it's Theta one + + align:start position:0% +the vs have been computed it's Theta one + + + align:start position:0% +the vs have been computed it's Theta one +time to compute a sub problem so that's + + align:start position:0% +time to compute a sub problem so that's + + + align:start position:0% +time to compute a sub problem so that's +your Theta 1 and U as before there + + align:start position:0% +your Theta 1 and U as before there + + + align:start position:0% +your Theta 1 and U as before there +are N squ Sub problems uh sorry let's + + align:start position:0% +are N squ Sub problems uh sorry let's + + + align:start position:0% +are N squ Sub problems uh sorry let's +just do number of sub + + align:start position:0% +just do number of sub + + + align:start position:0% +just do number of sub +problems times Theta 1 which is Theta n + + align:start position:0% +problems times Theta 1 which is Theta n + + + align:start position:0% +problems times Theta 1 which is Theta n +squ + + align:start position:0% +squ + + + align:start position:0% +squ +all right so that was good all right so + + align:start position:0% +all right so that was good all right so + + + align:start position:0% +all right so that was good all right so +uh good luck for the quiz uh and um + + align:start position:0% +uh good luck for the quiz uh and um + + + align:start position:0% +uh good luck for the quiz uh and um +don't worry too much about it uh see you + + align:start position:0% +don't worry too much about it uh see you + + + align:start position:0% +don't worry too much about it uh see you +guys next week \ No newline at end of file diff --git a/U1JYwHcFfso.txt b/U1JYwHcFfso.txt new file mode 100644 index 0000000000000000000000000000000000000000..225b2e023affb464157790f848f0e625cca541c5 --- /dev/null +++ b/U1JYwHcFfso.txt @@ -0,0 +1,9323 @@ +align:start position:0% + +all right welcome back to data + + align:start position:0% +all right welcome back to data + + + align:start position:0% +all right welcome back to data +structures land today we continue and + + align:start position:0% +structures land today we continue and + + + align:start position:0% +structures land today we continue and +complete our segment on binary trees so + + align:start position:0% +complete our segment on binary trees so + + + align:start position:0% +complete our segment on binary trees so +this is part two if you missed part one + + align:start position:0% +this is part two if you missed part one + + + align:start position:0% +this is part two if you missed part one +go back and watch part one um last time + + align:start position:0% +go back and watch part one um last time + + + align:start position:0% +go back and watch part one um last time +we talked about binary trees in general + + align:start position:0% +we talked about binary trees in general + + + align:start position:0% +we talked about binary trees in general +uh we had uh each node stored an item uh + + align:start position:0% +uh we had uh each node stored an item uh + + + align:start position:0% +uh we had uh each node stored an item uh +which and also a left pointer and a + + align:start position:0% +which and also a left pointer and a + + + align:start position:0% +which and also a left pointer and a +right pointer to other nodes and a + + align:start position:0% +right pointer to other nodes and a + + + align:start position:0% +right pointer to other nodes and a +parent pointer to another node uh this + + align:start position:0% +parent pointer to another node uh this + + + align:start position:0% +parent pointer to another node uh this +was an example of a tree B and C or A's + + align:start position:0% +was an example of a tree B and C or A's + + + align:start position:0% +was an example of a tree B and C or A's +children a is the parent of B and C and + + align:start position:0% +children a is the parent of B and C and + + + align:start position:0% +children a is the parent of B and C and +also the root of the entire tree we + + align:start position:0% +also the root of the entire tree we + + + align:start position:0% +also the root of the entire tree we +defined the height of a node we didn't + + align:start position:0% +defined the height of a node we didn't + + + align:start position:0% +defined the height of a node we didn't +use this too much yet but we're going to + + align:start position:0% +use this too much yet but we're going to + + + align:start position:0% +use this too much yet but we're going to +use it a lot today so remember the + + align:start position:0% +use it a lot today so remember the + + + align:start position:0% +use it a lot today so remember the +height is as drawn in red here um height + + align:start position:0% +height is as drawn in red here um height + + + align:start position:0% +height is as drawn in red here um height +of the node is the length of the longest + + align:start position:0% +of the node is the length of the longest + + + align:start position:0% +of the node is the length of the longest +downward path counting edges so B for + + align:start position:0% +downward path counting edges so B for + + + align:start position:0% +downward path counting edges so B for +example has a length two path so we + + align:start position:0% +example has a length two path so we + + + align:start position:0% +example has a length two path so we +write a two here you can also think of + + align:start position:0% +write a two here you can also think of + + + align:start position:0% +write a two here you can also think of +it is if you just live within the sub + + align:start position:0% +it is if you just live within the sub + + + align:start position:0% +it is if you just live within the sub +tree rooted at b b's subtree uh then uh + + align:start position:0% +tree rooted at b b's subtree uh then uh + + + align:start position:0% +tree rooted at b b's subtree uh then uh +what is the maximum depth of those nodes + + align:start position:0% +what is the maximum depth of those nodes + + + align:start position:0% +what is the maximum depth of those nodes +if you prefer to think about it that way + + align:start position:0% +if you prefer to think about it that way + + + align:start position:0% +if you prefer to think about it that way +either way is fine um and in particular + + align:start position:0% +either way is fine um and in particular + + + align:start position:0% +either way is fine um and in particular +we distinguished H the height of the + + align:start position:0% +we distinguished H the height of the + + + align:start position:0% +we distinguished H the height of the +root node as the height of the entire + + align:start position:0% +root node as the height of the entire + + + align:start position:0% +root node as the height of the entire +tree and what we achieved last time was + + align:start position:0% +tree and what we achieved last time was + + + align:start position:0% +tree and what we achieved last time was +basically all of our operations ran in + + align:start position:0% +basically all of our operations ran in + + + align:start position:0% +basically all of our operations ran in +order H time so um we had subtree insert + + align:start position:0% +order H time so um we had subtree insert + + + align:start position:0% +order H time so um we had subtree insert +subtree delete subtree first and last we + + align:start position:0% +subtree delete subtree first and last we + + + align:start position:0% +subtree delete subtree first and last we +could compute the predecessor and + + align:start position:0% +could compute the predecessor and + + + align:start position:0% +could compute the predecessor and +successor of a node all in order H time + + align:start position:0% +successor of a node all in order H time + + + align:start position:0% +successor of a node all in order H time +so as long as H was small uh we were + + align:start position:0% +so as long as H was small uh we were + + + align:start position:0% +so as long as H was small uh we were +happy um and remember what does + + align:start position:0% +happy um and remember what does + + + align:start position:0% +happy um and remember what does +predecessor and successor mean it's + + align:start position:0% +predecessor and successor mean it's + + + align:start position:0% +predecessor and successor mean it's +talking about an implicit order in the + + align:start position:0% +talking about an implicit order in the + + + align:start position:0% +talking about an implicit order in the +tree which is what we call traversal + + align:start position:0% +tree which is what we call traversal + + + align:start position:0% +tree which is what we call traversal +order which is defined recursively as + + align:start position:0% +order which is defined recursively as + + + align:start position:0% +order which is defined recursively as +recursively Traverse left sub tree then + + align:start position:0% +recursively Traverse left sub tree then + + + align:start position:0% +recursively Traverse left sub tree then +output the root then recursively + + align:start position:0% +output the root then recursively + + + align:start position:0% +output the root then recursively +Traverse the right sub tree so in this + + align:start position:0% +Traverse the right sub tree so in this + + + align:start position:0% +Traverse the right sub tree so in this +example the traversal order is f is the + + align:start position:0% +example the traversal order is f is the + + + align:start position:0% +example the traversal order is f is the +if you go all the way left that was the + + align:start position:0% +if you go all the way left that was the + + + align:start position:0% +if you go all the way left that was the +first in the traversal order uh then we + + align:start position:0% +first in the traversal order uh then we + + + align:start position:0% +first in the traversal order uh then we +have right make some space here uh then + + align:start position:0% +have right make some space here uh then + + + align:start position:0% +have right make some space here uh then +we have D then we have + + align:start position:0% +we have D then we have + + + align:start position:0% +we have D then we have +B then we do the right sub tree of B + + align:start position:0% +B then we do the right sub tree of B + + + align:start position:0% +B then we do the right sub tree of B +which is + + align:start position:0% +which is + + + align:start position:0% +which is +e then we have the root because we + + align:start position:0% +e then we have the root because we + + + align:start position:0% +e then we have the root because we +finished the left sub tree of the root + + align:start position:0% +finished the left sub tree of the root + + + align:start position:0% +finished the left sub tree of the root +so that's a and then we have + + align:start position:0% +so that's a and then we have + + + align:start position:0% +so that's a and then we have +C okay so there's an implicit linear + + align:start position:0% +C okay so there's an implicit linear + + + align:start position:0% +C okay so there's an implicit linear +order encoded by this tree and the whole + + align:start position:0% +order encoded by this tree and the whole + + + align:start position:0% +order encoded by this tree and the whole +point of binary trees is that we can + + align:start position:0% +point of binary trees is that we can + + + align:start position:0% +point of binary trees is that we can +efficiently update the tree uh much + + align:start position:0% +efficiently update the tree uh much + + + align:start position:0% +efficiently update the tree uh much +faster than we could explicitly write + + align:start position:0% +faster than we could explicitly write + + + align:start position:0% +faster than we could explicitly write +down an order in an array or something + + align:start position:0% +down an order in an array or something + + + align:start position:0% +down an order in an array or something +like that so binary trees let us quickly + + align:start position:0% +like that so binary trees let us quickly + + + align:start position:0% +like that so binary trees let us quickly +Now quickly is not so quick right now + + align:start position:0% +Now quickly is not so quick right now + + + align:start position:0% +Now quickly is not so quick right now +because everything is order H and in the + + align:start position:0% +because everything is order H and in the + + + align:start position:0% +because everything is order H and in the +worst case h is linear because we could + + align:start position:0% +worst case h is linear because we could + + + align:start position:0% +worst case h is linear because we could +have a tree like + + align:start position:0% + + + + align:start position:0% + +this but today we're going to make we're + + align:start position:0% +this but today we're going to make we're + + + align:start position:0% +this but today we're going to make we're +going to guarantee that H is log n and + + align:start position:0% +going to guarantee that H is log n and + + + align:start position:0% +going to guarantee that H is log n and +so the goal of today is to take all of + + align:start position:0% +so the goal of today is to take all of + + + align:start position:0% +so the goal of today is to take all of +these operations that run in order H + + align:start position:0% +these operations that run in order H + + + align:start position:0% +these operations that run in order H +time and get them to run in order log n + + align:start position:0% +time and get them to run in order log n + + + align:start position:0% +time and get them to run in order log n +time just by modifying the data + + align:start position:0% +time just by modifying the data + + + align:start position:0% +time just by modifying the data +structure we've already seen so we've + + align:start position:0% +structure we've already seen so we've + + + align:start position:0% +structure we've already seen so we've +done a lot of the hard work just a + + align:start position:0% +done a lot of the hard work just a + + + align:start position:0% +done a lot of the hard work just a +little bit more work we need to do today + + align:start position:0% +little bit more work we need to do today + + + align:start position:0% +little bit more work we need to do today +in something called AVL trees or height + + align:start position:0% +in something called AVL trees or height + + + align:start position:0% +in something called AVL trees or height +balance okay but before we get there I + + align:start position:0% +balance okay but before we get there I + + + align:start position:0% +balance okay but before we get there I +want to talk a little bit more at the + + align:start position:0% +want to talk a little bit more at the + + + align:start position:0% +want to talk a little bit more at the +very end of last leure we talked about + + align:start position:0% +very end of last leure we talked about + + + align:start position:0% +very end of last leure we talked about +once you have these subtree operations + + align:start position:0% +once you have these subtree operations + + + align:start position:0% +once you have these subtree operations +so I can insert and delete into subtree + + align:start position:0% +so I can insert and delete into subtree + + + align:start position:0% +so I can insert and delete into subtree +um how do I actually use that to solve + + align:start position:0% +um how do I actually use that to solve + + + align:start position:0% +um how do I actually use that to solve +the problems that we care about in this + + align:start position:0% +the problems that we care about in this + + + align:start position:0% +the problems that we care about in this +class which are sequence data structure + + align:start position:0% +class which are sequence data structure + + + align:start position:0% +class which are sequence data structure +and set data structure so um we talked + + align:start position:0% +and set data structure so um we talked + + + align:start position:0% +and set data structure so um we talked +mostly about the set data structure last + + align:start position:0% +mostly about the set data structure last + + + align:start position:0% +mostly about the set data structure last +time so in general we're going to Define + + align:start position:0% +time so in general we're going to Define + + + align:start position:0% +time so in general we're going to Define +what traversal order we maintain by a + + align:start position:0% +what traversal order we maintain by a + + + align:start position:0% +what traversal order we maintain by a +binary tree and so for a set um because + + align:start position:0% +binary tree and so for a set um because + + + align:start position:0% +binary tree and so for a set um because +we're for the set interface we're + + align:start position:0% +we're for the set interface we're + + + align:start position:0% +we're for the set interface we're +interested in doing + + align:start position:0% +interested in doing + + + align:start position:0% +interested in doing +uh queries like find next and find + + align:start position:0% +uh queries like find next and find + + + align:start position:0% +uh queries like find next and find +previous given a key if it's not there + + align:start position:0% +previous given a key if it's not there + + + align:start position:0% +previous given a key if it's not there +tell me the previous one or the next one + + align:start position:0% +tell me the previous one or the next one + + + align:start position:0% +tell me the previous one or the next one +this is something we could do with + + align:start position:0% +this is something we could do with + + + align:start position:0% +this is something we could do with +binary search and so the the big cool + + align:start position:0% +binary search and so the the big cool + + + align:start position:0% +binary search and so the the big cool +thing that binary trees let us do if we + + align:start position:0% +thing that binary trees let us do if we + + + align:start position:0% +thing that binary trees let us do if we +let the traversal order always be uh all + + align:start position:0% +let the traversal order always be uh all + + + align:start position:0% +let the traversal order always be uh all +of the items stored in increasing key + + align:start position:0% +of the items stored in increasing key + + + align:start position:0% +of the items stored in increasing key +order then we are effectively + + align:start position:0% +order then we are effectively + + + align:start position:0% +order then we are effectively +maintaining the items in + + align:start position:0% +maintaining the items in + + + align:start position:0% +maintaining the items in +order in in the traversal order sense + + align:start position:0% +order in in the traversal order sense + + + align:start position:0% +order in in the traversal order sense +again we're not explicitly maintaining + + align:start position:0% +again we're not explicitly maintaining + + + align:start position:0% +again we're not explicitly maintaining +them in order but up here we're + + align:start position:0% +them in order but up here we're + + + align:start position:0% +them in order but up here we're +maintaining a tree that that represents + + align:start position:0% +maintaining a tree that that represents + + + align:start position:0% +maintaining a tree that that represents +items in key order and so this lets us + + align:start position:0% +items in key order and so this lets us + + + align:start position:0% +items in key order and so this lets us +do uh a sub tree find operation which + + align:start position:0% +do uh a sub tree find operation which + + + align:start position:0% +do uh a sub tree find operation which +you could easily use to implement find + + align:start position:0% +you could easily use to implement find + + + align:start position:0% +you could easily use to implement find +and find previous and so on um as + + align:start position:0% +and find previous and so on um as + + + align:start position:0% +and find previous and so on um as +follows we start at the root of the tree + + align:start position:0% +follows we start at the root of the tree + + + align:start position:0% +follows we start at the root of the tree +so we could say node equals root + + align:start position:0% +so we could say node equals root + + + align:start position:0% +so we could say node equals root +initially and then we can recursively + + align:start position:0% +initially and then we can recursively + + + align:start position:0% +initially and then we can recursively +search for a key K as follows we check + + align:start position:0% +search for a key K as follows we check + + + align:start position:0% +search for a key K as follows we check +well if the item at the root has a key + + align:start position:0% +well if the item at the root has a key + + + align:start position:0% +well if the item at the root has a key +that's bigger than K let me draw a + + align:start position:0% +that's bigger than K let me draw a + + + align:start position:0% +that's bigger than K let me draw a +little + + align:start position:0% +little + + + align:start position:0% +little +picture + + align:start position:0% +picture + + + align:start position:0% +picture +uh so we're at some node + + align:start position:0% +uh so we're at some node + + + align:start position:0% +uh so we're at some node +here this is a + + align:start position:0% +here this is a + + + align:start position:0% +here this is a +node and it has a left sub tree and a + + align:start position:0% +node and it has a left sub tree and a + + + align:start position:0% +node and it has a left sub tree and a +right sub tree and there's some + + align:start position:0% +right sub tree and there's some + + + align:start position:0% +right sub tree and there's some +item with some key so if the key we're + + align:start position:0% +item with some key so if the key we're + + + align:start position:0% +item with some key so if the key we're +looking for is less than the nodes item + + align:start position:0% +looking for is less than the nodes item + + + align:start position:0% +looking for is less than the nodes item +that means it's down here in the left + + align:start position:0% +that means it's down here in the left + + + align:start position:0% +that means it's down here in the left +sub tree and so we recurse on node. left + + align:start position:0% +sub tree and so we recurse on node. left + + + align:start position:0% +sub tree and so we recurse on node. left +if they're equal that means that this + + align:start position:0% +if they're equal that means that this + + + align:start position:0% +if they're equal that means that this +item is the item we're looking for so we + + align:start position:0% +item is the item we're looking for so we + + + align:start position:0% +item is the item we're looking for so we +can just turn it or the node depending + + align:start position:0% +can just turn it or the node depending + + + align:start position:0% +can just turn it or the node depending +on what you're looking for and if the + + align:start position:0% +on what you're looking for and if the + + + align:start position:0% +on what you're looking for and if the +key in here is greater than the key + + align:start position:0% +key in here is greater than the key + + + align:start position:0% +key in here is greater than the key +we're looking for then we'll recurse to + + align:start position:0% +we're looking for then we'll recurse to + + + align:start position:0% +we're looking for then we'll recurse to +the + + align:start position:0% +the + + + align:start position:0% +the +right this if you think about it a + + align:start position:0% +right this if you think about it a + + + align:start position:0% +right this if you think about it a +little bit this is exactly binary search + + align:start position:0% +little bit this is exactly binary search + + + align:start position:0% +little bit this is exactly binary search +on an array it just happens to be on a + + align:start position:0% +on an array it just happens to be on a + + + align:start position:0% +on an array it just happens to be on a +tree instead if you think of an + + align:start position:0% + + + + align:start position:0% + +array um like this B where does binary + + align:start position:0% +array um like this B where does binary + + + align:start position:0% +array um like this B where does binary +stretch do it first looks at the key in + + align:start position:0% +stretch do it first looks at the key in + + + align:start position:0% +stretch do it first looks at the key in +the middle I'm going to draw that as the + + align:start position:0% +the middle I'm going to draw that as the + + + align:start position:0% +the middle I'm going to draw that as the +root uh and then uh it recurses either + + align:start position:0% +root uh and then uh it recurses either + + + align:start position:0% +root uh and then uh it recurses either +on the left chunk which I will draw + + align:start position:0% +on the left chunk which I will draw + + + align:start position:0% +on the left chunk which I will draw +recursively or on the right + + align:start position:0% +recursively or on the right + + + align:start position:0% +recursively or on the right +chunk and so if you happen to have a + + align:start position:0% +chunk and so if you happen to have a + + + align:start position:0% +chunk and so if you happen to have a +perfect binary tree like this one it is + + align:start position:0% +perfect binary tree like this one it is + + + align:start position:0% +perfect binary tree like this one it is +simulating exactly uh binary search in + + align:start position:0% +simulating exactly uh binary search in + + + align:start position:0% +simulating exactly uh binary search in +this array but this we're going to be + + align:start position:0% +this array but this we're going to be + + + align:start position:0% +this array but this we're going to be +able to maintain dynamically not perfect + + align:start position:0% +able to maintain dynamically not perfect + + + align:start position:0% +able to maintain dynamically not perfect +anymore but close uh whereas this we + + align:start position:0% +anymore but close uh whereas this we + + + align:start position:0% +anymore but close uh whereas this we +could not maintain in sorted order okay + + align:start position:0% +could not maintain in sorted order okay + + + align:start position:0% +could not maintain in sorted order okay +so uh this is like a generalization of + + align:start position:0% +so uh this is like a generalization of + + + align:start position:0% +so uh this is like a generalization of +binary search to work on trees instead + + align:start position:0% +binary search to work on trees instead + + + align:start position:0% +binary search to work on trees instead +of on arrays and for this reason set + + align:start position:0% +of on arrays and for this reason set + + + align:start position:0% +of on arrays and for this reason set +binary trees are called binary search + + align:start position:0% +binary trees are called binary search + + + align:start position:0% +binary trees are called binary search +trees because they are the tree version + + align:start position:0% +trees because they are the tree version + + + align:start position:0% +trees because they are the tree version +of binary search so there's many + + align:start position:0% +of binary search so there's many + + + align:start position:0% +of binary search so there's many +equivalent names so binary search tree + + align:start position:0% +equivalent names so binary search tree + + + align:start position:0% +equivalent names so binary search tree +is another name for set binary tree and + + align:start position:0% +is another name for set binary tree and + + + align:start position:0% +is another name for set binary tree and +the key thing that makes this algorithm + + align:start position:0% +the key thing that makes this algorithm + + + align:start position:0% +the key thing that makes this algorithm +work is so-called binary search tree + + align:start position:0% +work is so-called binary search tree + + + align:start position:0% +work is so-called binary search tree +property which is um all the keys in the + + align:start position:0% +property which is um all the keys in the + + + align:start position:0% +property which is um all the keys in the +left sub tree of a node are less than uh + + align:start position:0% +left sub tree of a node are less than uh + + + align:start position:0% +left sub tree of a node are less than uh +the root and all or of that node and + + align:start position:0% +the root and all or of that node and + + + align:start position:0% +the root and all or of that node and +that key that key is less than all the + + align:start position:0% +that key that key is less than all the + + + align:start position:0% +that key that key is less than all the +keys in the right sub tree and this is + + align:start position:0% +keys in the right sub tree and this is + + + align:start position:0% +keys in the right sub tree and this is +true recursively all the way down + + align:start position:0% +true recursively all the way down + + + align:start position:0% +true recursively all the way down +and so that's that's how you prove that + + align:start position:0% +and so that's that's how you prove that + + + align:start position:0% +and so that's that's how you prove that +this algorithm is correct by this + + align:start position:0% +this algorithm is correct by this + + + align:start position:0% +this algorithm is correct by this +property why is this true because uh if + + align:start position:0% +property why is this true because uh if + + + align:start position:0% +property why is this true because uh if +we can maintain traversal order to be + + align:start position:0% +we can maintain traversal order to be + + + align:start position:0% +we can maintain traversal order to be +increasing key then that's exactly what + + align:start position:0% +increasing key then that's exactly what + + + align:start position:0% +increasing key then that's exactly what +traversal order means it tells you all + + align:start position:0% +traversal order means it tells you all + + + align:start position:0% +traversal order means it tells you all +the things in the left sub tree come + + align:start position:0% +the things in the left sub tree come + + + align:start position:0% +the things in the left sub tree come +before the root which come before all + + align:start position:0% +before the root which come before all + + + align:start position:0% +before the root which come before all +the things in the right sub tree so uh + + align:start position:0% +the things in the right sub tree so uh + + + align:start position:0% +the things in the right sub tree so uh +this property implies this + + align:start position:0% +this property implies this + + + align:start position:0% +this property implies this +one and how do you maintain things in + + align:start position:0% +one and how do you maintain things in + + + align:start position:0% +one and how do you maintain things in +increasing key order it's pretty easy uh + + align:start position:0% +increasing key order it's pretty easy uh + + + align:start position:0% +increasing key order it's pretty easy uh +if you want to insert an item where does + + align:start position:0% +if you want to insert an item where does + + + align:start position:0% +if you want to insert an item where does +it belong well you do this search to + + align:start position:0% +it belong well you do this search to + + + align:start position:0% +it belong well you do this search to +find where it would belong if it was + + align:start position:0% +find where it would belong if it was + + + align:start position:0% +find where it would belong if it was +there if it's there you can overwrite + + align:start position:0% +there if it's there you can overwrite + + + align:start position:0% +there if it's there you can overwrite +the values stored with that key if it's + + align:start position:0% +the values stored with that key if it's + + + align:start position:0% +the values stored with that key if it's +not + + align:start position:0% +not + + + align:start position:0% +not +um this search will fall off the tree at + + align:start position:0% +um this search will fall off the tree at + + + align:start position:0% +um this search will fall off the tree at +some point and that's where you insert + + align:start position:0% +some point and that's where you insert + + + align:start position:0% +some point and that's where you insert +your uh a new node in your tree okay + + align:start position:0% +your uh a new node in your tree okay + + + align:start position:0% +your uh a new node in your tree okay +that was discovered in recitation so I + + align:start position:0% +that was discovered in recitation so I + + + align:start position:0% +that was discovered in recitation so I +don't want to dwell on it what I want to + + align:start position:0% +don't want to dwell on it what I want to + + + align:start position:0% +don't want to dwell on it what I want to +focus on today is the other application + + align:start position:0% +focus on today is the other application + + + align:start position:0% +focus on today is the other application +how do we this is for representing a set + + align:start position:0% +how do we this is for representing a set + + + align:start position:0% +how do we this is for representing a set +which is relatively easy uh a CH + + align:start position:0% +which is relatively easy uh a CH + + + align:start position:0% +which is relatively easy uh a CH +we sort of set ourselves up for but we + + align:start position:0% +we sort of set ourselves up for but we + + + align:start position:0% +we sort of set ourselves up for but we +need a little more work is to make + + align:start position:0% +need a little more work is to make + + + align:start position:0% +need a little more work is to make +sequence binary + + align:start position:0% +sequence binary + + + align:start position:0% +sequence binary +trees so suppose I have a binary tree + + align:start position:0% +trees so suppose I have a binary tree + + + align:start position:0% +trees so suppose I have a binary tree +and what I would like mentioned at the + + align:start position:0% +and what I would like mentioned at the + + + align:start position:0% +and what I would like mentioned at the +end of last time is that I want the + + align:start position:0% +end of last time is that I want the + + + align:start position:0% +end of last time is that I want the +traversal order of my tree to be the + + align:start position:0% +traversal order of my tree to be the + + + align:start position:0% +traversal order of my tree to be the +sequence + + align:start position:0% +sequence + + + align:start position:0% +sequence +order the order that I'm trying to + + align:start position:0% +order the order that I'm trying to + + + align:start position:0% +order the order that I'm trying to +represent that's changed by operations + + align:start position:0% +represent that's changed by operations + + + align:start position:0% +represent that's changed by operations +like insert + + align:start position:0% +like insert + + + align:start position:0% +like insert +at and so I just like to do the same + + align:start position:0% +at and so I just like to do the same + + + align:start position:0% +at and so I just like to do the same +thing but now I have to think about how + + align:start position:0% +thing but now I have to think about how + + + align:start position:0% +thing but now I have to think about how +do I do a search how do I do insert at + + align:start position:0% +do I do a search how do I do insert at + + + align:start position:0% +do I do a search how do I do insert at +that sort of thing and here is an + + align:start position:0% +that sort of thing and here is an + + + align:start position:0% +that sort of thing and here is an +algorithm for what I would like to work + + align:start position:0% +algorithm for what I would like to work + + + align:start position:0% +algorithm for what I would like to work +but it's not going to quite work yet so + + align:start position:0% +but it's not going to quite work yet so + + + align:start position:0% +but it's not going to quite work yet so +suppose I give you a sub tree so + + align:start position:0% +suppose I give you a sub tree so + + + align:start position:0% +suppose I give you a sub tree so +specified by a node so there's all the + + align:start position:0% +specified by a node so there's all the + + + align:start position:0% +specified by a node so there's all the +descendants of that node and I'd like to + + align:start position:0% +descendants of that node and I'd like to + + + align:start position:0% +descendants of that node and I'd like to +know what is in the traversal order of + + align:start position:0% +know what is in the traversal order of + + + align:start position:0% +know what is in the traversal order of +that subtree which starts here and ends + + align:start position:0% +that subtree which starts here and ends + + + align:start position:0% +that subtree which starts here and ends +here and the root will be somewhere in + + align:start position:0% +here and the root will be somewhere in + + + align:start position:0% +here and the root will be somewhere in +the + + align:start position:0% +the + + + align:start position:0% +the +middle give me the + + align:start position:0% +middle give me the + + + align:start position:0% +middle give me the +node so this if I ask I equals z i want + + align:start position:0% +node so this if I ask I equals z i want + + + align:start position:0% +node so this if I ask I equals z i want +to get this leftmost descendant if I ask + + align:start position:0% +to get this leftmost descendant if I ask + + + align:start position:0% +to get this leftmost descendant if I ask +for I equals the size of the tree minus + + align:start position:0% +for I equals the size of the tree minus + + + align:start position:0% +for I equals the size of the tree minus +one I want to get The rightmost + + align:start position:0% +one I want to get The rightmost + + + align:start position:0% +one I want to get The rightmost +Descendant that was the first and last + + align:start position:0% +Descendant that was the first and last + + + align:start position:0% +Descendant that was the first and last +in the sub tree that we talked about but + + align:start position:0% +in the sub tree that we talked about but + + + align:start position:0% +in the sub tree that we talked about but +we don't we know how to find the first + + align:start position:0% +we don't we know how to find the first + + + align:start position:0% +we don't we know how to find the first +and last just walk left or walk right + + align:start position:0% +and last just walk left or walk right + + + align:start position:0% +and last just walk left or walk right +but we don't know how to find the I + + align:start position:0% +but we don't know how to find the I + + + align:start position:0% +but we don't know how to find the I +node in order H time is the goal right + + align:start position:0% +node in order H time is the goal right + + + align:start position:0% +node in order H time is the goal right +now not log in and the idea is well it + + align:start position:0% +now not log in and the idea is well it + + + align:start position:0% +now not log in and the idea is well it +seems like size + + align:start position:0% +seems like size + + + align:start position:0% +seems like size +matters sorry if you heard otherwise um + + align:start position:0% +matters sorry if you heard otherwise um + + + align:start position:0% +matters sorry if you heard otherwise um +so in particular I I mentioned size when + + align:start position:0% +so in particular I I mentioned size when + + + align:start position:0% +so in particular I I mentioned size when +I was talking about the the last node in + + align:start position:0% +I was talking about the the last node in + + + align:start position:0% +I was talking about the the last node in +the sequence that the index of that node + + align:start position:0% +the sequence that the index of that node + + + align:start position:0% +the sequence that the index of that node +is size of this subtree minus one so + + align:start position:0% +is size of this subtree minus one so + + + align:start position:0% +is size of this subtree minus one so +let's define the size of a + + align:start position:0% + + + + align:start position:0% + +node to be uh the number of nodes in its + + align:start position:0% +node to be uh the number of nodes in its + + + align:start position:0% +node to be uh the number of nodes in its +sub tree we're calling that subtree + + align:start position:0% +sub tree we're calling that subtree + + + align:start position:0% +sub tree we're calling that subtree +paren + + align:start position:0% + + + + align:start position:0% + +node okay including the node + + align:start position:0% +node okay including the node + + + align:start position:0% +node okay including the node +itself so if I somehow knew the size + + align:start position:0% +itself so if I somehow knew the size + + + align:start position:0% +itself so if I somehow knew the size +this seems important for understanding + + align:start position:0% +this seems important for understanding + + + align:start position:0% +this seems important for understanding +indexes let's just assume that I knew + + align:start position:0% +indexes let's just assume that I knew + + + align:start position:0% +indexes let's just assume that I knew +that magically in constant + + align:start position:0% +that magically in constant + + + align:start position:0% +that magically in constant +time okay uh then I claim that the size + + align:start position:0% +time okay uh then I claim that the size + + + align:start position:0% +time okay uh then I claim that the size +of the left sub tree so why don't I + + align:start position:0% +of the left sub tree so why don't I + + + align:start position:0% +of the left sub tree so why don't I +expand this diagram a little + + align:start position:0% + + + + align:start position:0% + +bit so we we have node as + + align:start position:0% +bit so we we have node as + + + align:start position:0% +bit so we we have node as +before but we have a left sub tree and a + + align:start position:0% +before but we have a left sub tree and a + + + align:start position:0% +before but we have a left sub tree and a +right sub tree so this node here is + + align:start position:0% +right sub tree so this node here is + + + align:start position:0% +right sub tree so this node here is +node. left this node here is node. right + + align:start position:0% +node. left this node here is node. right + + + align:start position:0% +node. left this node here is node. right +they might not exist but let's ignore + + align:start position:0% +they might not exist but let's ignore + + + align:start position:0% +they might not exist but let's ignore +those exceptional cases for now let's + + align:start position:0% +those exceptional cases for now let's + + + align:start position:0% +those exceptional cases for now let's +suppose we knew not only the size of + + align:start position:0% +suppose we knew not only the size of + + + align:start position:0% +suppose we knew not only the size of +node but we knew the size of node. left + + align:start position:0% +node but we knew the size of node. left + + + align:start position:0% +node but we knew the size of node. left +so that is the size of this tree on the + + align:start position:0% +so that is the size of this tree on the + + + align:start position:0% +so that is the size of this tree on the +left I'm going to call that NL so let's + + align:start position:0% +left I'm going to call that NL so let's + + + align:start position:0% +left I'm going to call that NL so let's +suppose that there are NL nodes down + + align:start position:0% +suppose that there are NL nodes down + + + align:start position:0% +suppose that there are NL nodes down +here why I claim that lets me do the + + align:start position:0% +here why I claim that lets me do the + + + align:start position:0% +here why I claim that lets me do the +equivalent of a binary + + align:start position:0% +equivalent of a binary + + + align:start position:0% +equivalent of a binary +search cuz I'm looking for some index I + + align:start position:0% +search cuz I'm looking for some index I + + + align:start position:0% +search cuz I'm looking for some index I +and if I is less than NL then I know + + align:start position:0% +and if I is less than NL then I know + + + align:start position:0% +and if I is less than NL then I know +that it must be down here for example if + + align:start position:0% +that it must be down here for example if + + + align:start position:0% +that it must be down here for example if +I equals z it's going to be in the left + + align:start position:0% +I equals z it's going to be in the left + + + align:start position:0% +I equals z it's going to be in the left +sub tree as long as NL is greater than + + align:start position:0% +sub tree as long as NL is greater than + + + align:start position:0% +sub tree as long as NL is greater than +zero right so uh that's exactly this + + align:start position:0% +zero right so uh that's exactly this + + + align:start position:0% +zero right so uh that's exactly this +check if I is less than NL I'm going to + + align:start position:0% +check if I is less than NL I'm going to + + + align:start position:0% +check if I is less than NL I'm going to +recurse to the left call subt tree at of + + align:start position:0% +recurse to the left call subt tree at of + + + align:start position:0% +recurse to the left call subt tree at of +no do left comma + + align:start position:0% +no do left comma + + + align:start position:0% +no do left comma +I that's what's written here um if I + + align:start position:0% +I that's what's written here um if I + + + align:start position:0% +I that's what's written here um if I +equals NL + + align:start position:0% +equals NL + + + align:start position:0% +equals NL +if you think about it for a second so NL + + align:start position:0% +if you think about it for a second so NL + + + align:start position:0% +if you think about it for a second so NL +is the number of nodes here and so that + + align:start position:0% +is the number of nodes here and so that + + + align:start position:0% +is the number of nodes here and so that +means this node has index NL the index + + align:start position:0% +means this node has index NL the index + + + align:start position:0% +means this node has index NL the index +of this node is NL and so if I equals + + align:start position:0% +of this node is NL and so if I equals + + + align:start position:0% +of this node is NL and so if I equals +the if the one index we're looking for + + align:start position:0% +the if the one index we're looking for + + + align:start position:0% +the if the one index we're looking for +is that one then we just return this + + align:start position:0% +is that one then we just return this + + + align:start position:0% +is that one then we just return this +node we're + + align:start position:0% +node we're + + + align:start position:0% +node we're +done and otherwise I is greater than NL + + align:start position:0% +done and otherwise I is greater than NL + + + align:start position:0% +done and otherwise I is greater than NL +and that means that the node we're + + align:start position:0% +and that means that the node we're + + + align:start position:0% +and that means that the node we're +looking for is in the right sub tree + + align:start position:0% +looking for is in the right sub tree + + + align:start position:0% +looking for is in the right sub tree +because it comes after the root again + + align:start position:0% +because it comes after the root again + + + align:start position:0% +because it comes after the root again +that's what it means that's what + + align:start position:0% +that's what it means that's what + + + align:start position:0% +that's what it means that's what +traversal order means so if we Define it + + align:start position:0% +traversal order means so if we Define it + + + align:start position:0% +traversal order means so if we Define it +to be sequence order + + align:start position:0% +to be sequence order + + + align:start position:0% +to be sequence order +uh then we know all the things that come + + align:start position:0% +uh then we know all the things that come + + + align:start position:0% +uh then we know all the things that come +after this node which is index NL must + + align:start position:0% +after this node which is index NL must + + + align:start position:0% +after this node which is index NL must +be over here now when we recurse down + + align:start position:0% +be over here now when we recurse down + + + align:start position:0% +be over here now when we recurse down +here our numbering system changes + + align:start position:0% +here our numbering system changes + + + align:start position:0% +here our numbering system changes +because out in for node zero is here and + + align:start position:0% +because out in for node zero is here and + + + align:start position:0% +because out in for node zero is here and +then for node. right Zer is here so we + + align:start position:0% +then for node. right Zer is here so we + + + align:start position:0% +then for node. right Zer is here so we +need to do a little bit of subtraction + + align:start position:0% +need to do a little bit of subtraction + + + align:start position:0% +need to do a little bit of subtraction +here which is when we recurse to the + + align:start position:0% +here which is when we recurse to the + + + align:start position:0% +here which is when we recurse to the +right we take IUS NL minus one minus NL + + align:start position:0% +right we take IUS NL minus one minus NL + + + align:start position:0% +right we take IUS NL minus one minus NL +for these guys minus one for the root + + align:start position:0% +for these guys minus one for the root + + + align:start position:0% +for these guys minus one for the root +node um and that will give us the index + + align:start position:0% +node um and that will give us the index + + + align:start position:0% +node um and that will give us the index +we're looking for within this sub + + align:start position:0% +we're looking for within this sub + + + align:start position:0% +we're looking for within this sub +okay so it's my point is this algorithm + + align:start position:0% +okay so it's my point is this algorithm + + + align:start position:0% +okay so it's my point is this algorithm +is basically the same as this algorithm + + align:start position:0% +is basically the same as this algorithm + + + align:start position:0% +is basically the same as this algorithm +but this one uses keys because we're + + align:start position:0% +but this one uses keys because we're + + + align:start position:0% +but this one uses keys because we're +dealing with a set and in sets we assume + + align:start position:0% +dealing with a set and in sets we assume + + + align:start position:0% +dealing with a set and in sets we assume +items have keys over here we items don't + + align:start position:0% +items have keys over here we items don't + + + align:start position:0% +items have keys over here we items don't +have to have keys in fact we're not + + align:start position:0% +have to have keys in fact we're not + + + align:start position:0% +have to have keys in fact we're not +touching the items at all we're just + + align:start position:0% +touching the items at all we're just + + + align:start position:0% +touching the items at all we're just +asking what is the I item in my sequence + + align:start position:0% +asking what is the I item in my sequence + + + align:start position:0% +asking what is the I item in my sequence +which is the same thing as what is the I + + align:start position:0% +which is the same thing as what is the I + + + align:start position:0% +which is the same thing as what is the I +item in my traversal order which is the + + align:start position:0% +item in my traversal order which is the + + + align:start position:0% +item in my traversal order which is the +same thing as asking what is the I node + + align:start position:0% +same thing as asking what is the I node + + + align:start position:0% +same thing as asking what is the I node +in the traversal order and this + + align:start position:0% +in the traversal order and this + + + align:start position:0% +in the traversal order and this +algorithm gives it to you exactly the + + align:start position:0% +algorithm gives it to you exactly the + + + align:start position:0% +algorithm gives it to you exactly the +same way + + align:start position:0% +same way + + + align:start position:0% +same way +in order H + + align:start position:0% +in order H + + + align:start position:0% +in order H +time okay now I'm not going to show you + + align:start position:0% +time okay now I'm not going to show you + + + align:start position:0% +time okay now I'm not going to show you +all the operations but you can use subt + + align:start position:0% +all the operations but you can use subt + + + align:start position:0% +all the operations but you can use subt +tree at to + + align:start position:0% +tree at to + + + align:start position:0% +tree at to +implement uh get at and set at you just + + align:start position:0% +implement uh get at and set at you just + + + align:start position:0% +implement uh get at and set at you just +find the appropriate node and return the + + align:start position:0% +find the appropriate node and return the + + + align:start position:0% +find the appropriate node and return the +item or modify the item uh or you can + + align:start position:0% +item or modify the item uh or you can + + + align:start position:0% +item or modify the item uh or you can +use it to most crucially you can use it + + align:start position:0% +use it to most crucially you can use it + + + align:start position:0% +use it to most crucially you can use it +to do insert at and delete at this is a + + align:start position:0% +to do insert at and delete at this is a + + + align:start position:0% +to do insert at and delete at this is a +new thing we've never been able to do + + align:start position:0% +new thing we've never been able to do + + + align:start position:0% +new thing we've never been able to do +before uh what do you do just like over + + align:start position:0% +before uh what do you do just like over + + + align:start position:0% +before uh what do you do just like over +here if I'm trying to insert an item I + + align:start position:0% +here if I'm trying to insert an item I + + + align:start position:0% +here if I'm trying to insert an item I +search for that item over here uh so if + + align:start position:0% +search for that item over here uh so if + + + align:start position:0% +search for that item over here uh so if +I'm trying to insert at I for example I + + align:start position:0% +I'm trying to insert at I for example I + + + align:start position:0% +I'm trying to insert at I for example I +look for I and then + + align:start position:0% +look for I and then + + + align:start position:0% +look for I and then +uh for insert at I I want to add a new + + align:start position:0% +uh for insert at I I want to add a new + + + align:start position:0% +uh for insert at I I want to add a new +item just before that one and + + align:start position:0% +item just before that one and + + + align:start position:0% +item just before that one and +conveniently we already have I didn't + + align:start position:0% +conveniently we already have I didn't + + + align:start position:0% +conveniently we already have I didn't +mention but we have a subtree insert we + + align:start position:0% +mention but we have a subtree insert we + + + align:start position:0% +mention but we have a subtree insert we +had two versions before and + + align:start position:0% + + + + align:start position:0% + +after I think we cover it + + align:start position:0% +after I think we cover it + + + align:start position:0% +after I think we cover it +after which is success before use + + align:start position:0% +after which is success before use + + + align:start position:0% +after which is success before use +predecessor uh but we can just call + + align:start position:0% +predecessor uh but we can just call + + + align:start position:0% +predecessor uh but we can just call +subtree insert before at that node and + + align:start position:0% +subtree insert before at that node and + + + align:start position:0% +subtree insert before at that node and +boom we will have added a new item just + + align:start position:0% +boom we will have added a new item just + + + align:start position:0% +boom we will have added a new item just +before it um and great so magically + + align:start position:0% +before it um and great so magically + + + align:start position:0% +before it um and great so magically +somehow uh we have inserted in the + + align:start position:0% +somehow uh we have inserted in the + + + align:start position:0% +somehow uh we have inserted in the +middle of the sequence and all of the + + align:start position:0% +middle of the sequence and all of the + + + align:start position:0% +middle of the sequence and all of the +indices update because I'm not storing + + align:start position:0% +indices update because I'm not storing + + + align:start position:0% +indices update because I'm not storing +indices instead I'm to search for an + + align:start position:0% +indices instead I'm to search for an + + + align:start position:0% +indices instead I'm to search for an +item at index I I'm using the search + + align:start position:0% +item at index I I'm using the search + + + align:start position:0% +item at index I I'm using the search +algorithm but + + align:start position:0% +algorithm but + + + align:start position:0% +algorithm but +there's a problem what's the + + align:start position:0% + + + + align:start position:0% + +problem this seems a little too good to + + align:start position:0% +problem this seems a little too good to + + + align:start position:0% +problem this seems a little too good to +be + + align:start position:0% +be + + + align:start position:0% +be +true I insert in the middle of this tree + + align:start position:0% +true I insert in the middle of this tree + + + align:start position:0% +true I insert in the middle of this tree +and then somehow I can magically search + + align:start position:0% +and then somehow I can magically search + + + align:start position:0% +and then somehow I can magically search +and still find the I item even though + + align:start position:0% +and still find the I item even though + + + align:start position:0% +and still find the I item even though +all the indices to the right of that + + align:start position:0% +all the indices to the right of that + + + align:start position:0% +all the indices to the right of that +item incremented by + + align:start position:0% + + + + align:start position:0% + +one it's almost true question + + align:start position:0% + + + + align:start position:0% + +answer yeah + + align:start position:0% +answer yeah + + + align:start position:0% +answer yeah +because we have to update the SI because + + align:start position:0% +because we have to update the SI because + + + align:start position:0% +because we have to update the SI because +we have to update the sizes right I + + align:start position:0% +we have to update the sizes right I + + + align:start position:0% +we have to update the sizes right I +didn't say how do I compute the size of + + align:start position:0% +didn't say how do I compute the size of + + + align:start position:0% +didn't say how do I compute the size of +the left sub tree so that is the next + + align:start position:0% + + + + align:start position:0% + +topic we're almost done this this will + + align:start position:0% +topic we're almost done this this will + + + align:start position:0% +topic we're almost done this this will +actually work it's really quite awesome + + align:start position:0% +actually work it's really quite awesome + + + align:start position:0% +actually work it's really quite awesome +but uh for it to work we need something + + align:start position:0% +but uh for it to work we need something + + + align:start position:0% +but uh for it to work we need something +called sub tree + + align:start position:0% +called sub tree + + + align:start position:0% +called sub tree +augmentation which I'll talk about + + align:start position:0% +augmentation which I'll talk about + + + align:start position:0% +augmentation which I'll talk about +generally and then we'll apply it to + + align:start position:0% +generally and then we'll apply it to + + + align:start position:0% +generally and then we'll apply it to +size + + align:start position:0% + + + + align:start position:0% + +so the idea with subtree augmentation is + + align:start position:0% +so the idea with subtree augmentation is + + + align:start position:0% +so the idea with subtree augmentation is +that uh each node in our binary tree uh + + align:start position:0% +that uh each node in our binary tree uh + + + align:start position:0% +that uh each node in our binary tree uh +can + + align:start position:0% +can + + + align:start position:0% +can +store uh constant number of extra + + align:start position:0% +store uh constant number of extra + + + align:start position:0% +store uh constant number of extra +Fields why + + align:start position:0% +Fields why + + + align:start position:0% +Fields why +not and in particular if these fields + + align:start position:0% +not and in particular if these fields + + + align:start position:0% +not and in particular if these fields +are of a particular type or maybe I'll + + align:start position:0% +are of a particular type or maybe I'll + + + align:start position:0% +are of a particular type or maybe I'll +call them + + align:start position:0% + + + + align:start position:0% + +properties I'm going to define a a + + align:start position:0% +properties I'm going to define a a + + + align:start position:0% +properties I'm going to define a a +subtree + + align:start position:0% + + + + align:start position:0% + +property uh to be something that can be + + align:start position:0% + + + + align:start position:0% + +computed from the + + align:start position:0% +computed from the + + + align:start position:0% +computed from the +properties of the nodes + + align:start position:0% + + + + align:start position:0% + +children so I should say this is of a + + align:start position:0% + + + + align:start position:0% + +node so children are node. left and no. + + align:start position:0% +node so children are node. left and no. + + + align:start position:0% +node so children are node. left and no. +right uh you can also access constant + + align:start position:0% +right uh you can also access constant + + + align:start position:0% +right uh you can also access constant +amount of other stuff for example the + + align:start position:0% +amount of other stuff for example the + + + align:start position:0% +amount of other stuff for example the +node + + align:start position:0% +node + + + align:start position:0% +node +itself uh but the point of a subtree + + align:start position:0% +itself uh but the point of a subtree + + + align:start position:0% +itself uh but the point of a subtree +property is it's downward looking if I + + align:start position:0% +property is it's downward looking if I + + + align:start position:0% +property is it's downward looking if I +have a + + align:start position:0% +have a + + + align:start position:0% +have a +node + + align:start position:0% +node + + + align:start position:0% +node +here + + align:start position:0% +here + + + align:start position:0% +here +and I want to compute some property + + align:start position:0% +and I want to compute some property + + + align:start position:0% +and I want to compute some property +about it call it uh we want to store P + + align:start position:0% +about it call it uh we want to store P + + + align:start position:0% +about it call it uh we want to store P +of the node and suppose we already know + + align:start position:0% +of the node and suppose we already know + + + align:start position:0% +of the node and suppose we already know +p over here the property computed for + + align:start position:0% +p over here the property computed for + + + align:start position:0% +p over here the property computed for +the left subtree or for the left node + + align:start position:0% +the left subtree or for the left node + + + align:start position:0% +the left subtree or for the left node +and we already know the property for the + + align:start position:0% +and we already know the property for the + + + align:start position:0% +and we already know the property for the +right node then uh what I'd like is for + + align:start position:0% +right node then uh what I'd like is for + + + align:start position:0% +right node then uh what I'd like is for +this to be computable in constant + + align:start position:0% + + + + align:start position:0% + +time so I can compute P of this node + + align:start position:0% +time so I can compute P of this node + + + align:start position:0% +time so I can compute P of this node +given P of the left node and P of the + + align:start position:0% +given P of the left node and P of the + + + align:start position:0% +given P of the left node and P of the +right node that's a sub tree property + + align:start position:0% +right node that's a sub tree property + + + align:start position:0% +right node that's a sub tree property +now in + + align:start position:0% +now in + + + align:start position:0% +now in +particular size is a sub tree + + align:start position:0% +particular size is a sub tree + + + align:start position:0% +particular size is a sub tree +property why + + align:start position:0% +property why + + + align:start position:0% +property why +because I can write this kind of + + align:start position:0% +because I can write this kind of + + + align:start position:0% +because I can write this kind of +recurrence uh node. + + align:start position:0% +recurrence uh node. + + + align:start position:0% +recurrence uh node. +size equals no do left do + + align:start position:0% +size equals no do left do + + + align:start position:0% +size equals no do left do +size is very tedious to + + align:start position:0% +size is very tedious to + + + align:start position:0% +size is very tedious to +write plus no do right. size + + align:start position:0% + + + + align:start position:0% + +plus one thank + + align:start position:0% +plus one thank + + + align:start position:0% +plus one thank +you size of the sub of the entire sub + + align:start position:0% +you size of the sub of the entire sub + + + align:start position:0% +you size of the sub of the entire sub +tree here called node um is the size of + + align:start position:0% +tree here called node um is the size of + + + align:start position:0% +tree here called node um is the size of +the left sub tree plus the size of the + + align:start position:0% +the left sub tree plus the size of the + + + align:start position:0% +the left sub tree plus the size of the +right sub tree plus one for that node + + align:start position:0% +right sub tree plus one for that node + + + align:start position:0% +right sub tree plus one for that node +itself okay so this is an update rule + + align:start position:0% +itself okay so this is an update rule + + + align:start position:0% +itself okay so this is an update rule +takes constant time to evaluate it's two + + align:start position:0% +takes constant time to evaluate it's two + + + align:start position:0% +takes constant time to evaluate it's two +additions sorry my T's look kind of like + + align:start position:0% +additions sorry my T's look kind of like + + + align:start position:0% +additions sorry my T's look kind of like +plus + + align:start position:0% + + + + align:start position:0% + +signs make the pluses a little + + align:start position:0% + + + + align:start position:0% + +bigger okay so we're summing those three + + align:start position:0% +bigger okay so we're summing those three + + + align:start position:0% +bigger okay so we're summing those three +things boom we can get node do size so I + + align:start position:0% +things boom we can get node do size so I + + + align:start position:0% +things boom we can get node do size so I +claim that uh if as long as my property + + align:start position:0% +claim that uh if as long as my property + + + align:start position:0% +claim that uh if as long as my property +has this feature I can maintain it + + align:start position:0% +has this feature I can maintain it + + + align:start position:0% +has this feature I can maintain it +dynamically as I'm changing the + + align:start position:0% +dynamically as I'm changing the + + + align:start position:0% +dynamically as I'm changing the +tree okay now this is a little bit of a + + align:start position:0% +tree okay now this is a little bit of a + + + align:start position:0% +tree okay now this is a little bit of a +forward reference because we haven't + + align:start position:0% +forward reference because we haven't + + + align:start position:0% +forward reference because we haven't +said exactly how we're going to change + + align:start position:0% +said exactly how we're going to change + + + align:start position:0% +said exactly how we're going to change +the tree yet but uh question if um no SI + + align:start position:0% +the tree yet but uh question if um no SI + + + align:start position:0% +the tree yet but uh question if um no SI +is recursive yeah how is it happen would + + align:start position:0% +is recursive yeah how is it happen would + + + align:start position:0% +is recursive yeah how is it happen would +okay why is this okay good question so + + align:start position:0% +okay why is this okay good question so + + + align:start position:0% +okay why is this okay good question so +one natural way you can think of this as + + align:start position:0% +one natural way you can think of this as + + + align:start position:0% +one natural way you can think of this as +a recursion which gives you a recursive + + align:start position:0% +a recursion which gives you a recursive + + + align:start position:0% +a recursion which gives you a recursive +algorithm uh so I wrote but I didn't + + align:start position:0% +algorithm uh so I wrote but I didn't + + + align:start position:0% +algorithm uh so I wrote but I didn't +write it but I could have written size + + align:start position:0% +write it but I could have written size + + + align:start position:0% +write it but I could have written size +of node equals this size of node. left + + align:start position:0% +of node equals this size of node. left + + + align:start position:0% +of node equals this size of node. left +plus and that would give you a linear + + align:start position:0% +plus and that would give you a linear + + + align:start position:0% +plus and that would give you a linear +time algorithm to count the size and if + + align:start position:0% +time algorithm to count the size and if + + + align:start position:0% +time algorithm to count the size and if +you don't have any information that + + align:start position:0% +you don't have any information that + + + align:start position:0% +you don't have any information that +is what you would do and that would be + + align:start position:0% +is what you would do and that would be + + + align:start position:0% +is what you would do and that would be +very painful so that would would make + + align:start position:0% +very painful so that would would make + + + align:start position:0% +very painful so that would would make +this algorithm really slow if I'm + + align:start position:0% +this algorithm really slow if I'm + + + align:start position:0% +this algorithm really slow if I'm +calling sizes a recursive function it's + + align:start position:0% +calling sizes a recursive function it's + + + align:start position:0% +calling sizes a recursive function it's +bad uh what I'm instead doing is storing + + align:start position:0% +bad uh what I'm instead doing is storing + + + align:start position:0% +bad uh what I'm instead doing is storing +the sizes on every single + + align:start position:0% +the sizes on every single + + + align:start position:0% +the sizes on every single +node okay and precomputing this so in + + align:start position:0% +node okay and precomputing this so in + + + align:start position:0% +node okay and precomputing this so in +fact I'm going to Define uh size of node + + align:start position:0% +fact I'm going to Define uh size of node + + + align:start position:0% +fact I'm going to Define uh size of node +in so this is the definition + + align:start position:0% +in so this is the definition + + + align:start position:0% +in so this is the definition +mathematically but the algorithm for + + align:start position:0% +mathematically but the algorithm for + + + align:start position:0% +mathematically but the algorithm for +this function is just going to be return + + align:start position:0% +this function is just going to be return + + + align:start position:0% +this function is just going to be return +node. size okay so that's constant time + + align:start position:0% +node. size okay so that's constant time + + + align:start position:0% +node. size okay so that's constant time +so I the challenge now is I have to keep + + align:start position:0% +so I the challenge now is I have to keep + + + align:start position:0% +so I the challenge now is I have to keep +these sizes up to dat no matter what I + + align:start position:0% +these sizes up to dat no matter what I + + + align:start position:0% +these sizes up to dat no matter what I +do to the tree and you could look back + + align:start position:0% +do to the tree and you could look back + + + align:start position:0% +do to the tree and you could look back +at last lecture and see okay what were + + align:start position:0% +at last lecture and see okay what were + + + align:start position:0% +at last lecture and see okay what were +all the changes that I did in a tree uh + + align:start position:0% +all the changes that I did in a tree uh + + + align:start position:0% +all the changes that I did in a tree uh +we only did changes during insert and + + align:start position:0% +we only did changes during insert and + + + align:start position:0% +we only did changes during insert and +delete and I will just claim to you when + + align:start position:0% +delete and I will just claim to you when + + + align:start position:0% +delete and I will just claim to you when +we did uh insert and + + align:start position:0% +we did uh insert and + + + align:start position:0% +we did uh insert and +delete what they ended up + + align:start position:0% +delete what they ended up + + + align:start position:0% +delete what they ended up +doing uh in the + + align:start position:0% +doing uh in the + + + align:start position:0% +doing uh in the +end they add or + + align:start position:0% +end they add or + + + align:start position:0% +end they add or +remove a leaf of the + + align:start position:0% + + + + align:start position:0% + +tree okay remember Leaf was a node with + + align:start position:0% +tree okay remember Leaf was a node with + + + align:start position:0% +tree okay remember Leaf was a node with +no children um so let's just think about + + align:start position:0% +no children um so let's just think about + + + align:start position:0% +no children um so let's just think about +if I add a new Leaf in a tree here's a + + align:start position:0% +if I add a new Leaf in a tree here's a + + + align:start position:0% +if I add a new Leaf in a tree here's a +tree suppose I add a leaf here which sub + + align:start position:0% +tree suppose I add a leaf here which sub + + + align:start position:0% +tree suppose I add a leaf here which sub +trees + + align:start position:0% +trees + + + align:start position:0% +trees +change well which sub trees contain that + + align:start position:0% +change well which sub trees contain that + + + align:start position:0% +change well which sub trees contain that +node it it is its own new sub tree then + + align:start position:0% +node it it is its own new sub tree then + + + align:start position:0% +node it it is its own new sub tree then +its parents it's in it's in its parents + + align:start position:0% +its parents it's in it's in its parents + + + align:start position:0% +its parents it's in it's in its parents +sub tree and its grandparents sub tree + + align:start position:0% +sub tree and its grandparents sub tree + + + align:start position:0% +sub tree and its grandparents sub tree +and and the overall sub tree okay in + + align:start position:0% +and and the overall sub tree okay in + + + align:start position:0% +and and the overall sub tree okay in +general these nodes are called the + + align:start position:0% +general these nodes are called the + + + align:start position:0% +general these nodes are called the +ancestors of this node that we added and + + align:start position:0% +ancestors of this node that we added and + + + align:start position:0% +ancestors of this node that we added and +those are the ones that update this sub + + align:start position:0% +those are the ones that update this sub + + + align:start position:0% +those are the ones that update this sub +tree over here didn't change it didn't + + align:start position:0% +tree over here didn't change it didn't + + + align:start position:0% +tree over here didn't change it didn't +change size and because it's a sub tree + + align:start position:0% +change size and because it's a sub tree + + + align:start position:0% +change size and because it's a sub tree +property no subtree property will change + + align:start position:0% +property no subtree property will change + + + align:start position:0% +property no subtree property will change +over here because the sub tree was + + align:start position:0% +over here because the sub tree was + + + align:start position:0% +over here because the sub tree was +untouched okay so + + align:start position:0% +untouched okay so + + + align:start position:0% +untouched okay so +um when I touch this guy I just have to + + align:start position:0% +um when I touch this guy I just have to + + + align:start position:0% +um when I touch this guy I just have to +update the sub tree property here update + + align:start position:0% +update the sub tree property here update + + + align:start position:0% +update the sub tree property here update +the subtree property here update the + + align:start position:0% +the subtree property here update the + + + align:start position:0% +the subtree property here update the +subtree property here how many of these + + align:start position:0% +subtree property here how many of these + + + align:start position:0% +subtree property here how many of these +are there + + align:start position:0% + + + + align:start position:0% + +yeah H I'll say order H to be safe but I + + align:start position:0% +yeah H I'll say order H to be safe but I + + + align:start position:0% +yeah H I'll say order H to be safe but I +think it's exactly H um so also when I + + align:start position:0% +think it's exactly H um so also when I + + + align:start position:0% +think it's exactly H um so also when I +remove a leaf the same thing if I remove + + align:start position:0% +remove a leaf the same thing if I remove + + + align:start position:0% +remove a leaf the same thing if I remove +this Leaf then the the sub trees that + + align:start position:0% +this Leaf then the the sub trees that + + + align:start position:0% +this Leaf then the the sub trees that +change are exactly its former + + align:start position:0% + + + + align:start position:0% + +ancestors + + align:start position:0% +ancestors + + + align:start position:0% +ancestors +uh cool so + + align:start position:0% +uh cool so + + + align:start position:0% +uh cool so +um we're going to update those order + + align:start position:0% +um we're going to update those order + + + align:start position:0% +um we're going to update those order +H uh + + align:start position:0% + + + + align:start position:0% + +ancestors um in + + align:start position:0% +ancestors um in + + + align:start position:0% +ancestors um in +order up the + + align:start position:0% +order up the + + + align:start position:0% +order up the +tree so what do I mean by update I mean + + align:start position:0% +tree so what do I mean by update I mean + + + align:start position:0% +tree so what do I mean by update I mean +apply this rule for sub for size it's + + align:start position:0% +apply this rule for sub for size it's + + + align:start position:0% +apply this rule for sub for size it's +this rule but for in general the subtree + + align:start position:0% +this rule but for in general the subtree + + + align:start position:0% +this rule but for in general the subtree +property gives me an update rule that + + align:start position:0% +property gives me an update rule that + + + align:start position:0% +property gives me an update rule that +takes constant time and so I'm going to + + align:start position:0% +takes constant time and so I'm going to + + + align:start position:0% +takes constant time and so I'm going to +apply that update rule to this node + + align:start position:0% +apply that update rule to this node + + + align:start position:0% +apply that update rule to this node +which will fix whatever property is + + align:start position:0% +which will fix whatever property is + + + align:start position:0% +which will fix whatever property is +stored in there maybe there's more than + + align:start position:0% +stored in there maybe there's more than + + + align:start position:0% +stored in there maybe there's more than +one property and then I'll apply it to + + align:start position:0% +one property and then I'll apply it to + + + align:start position:0% +one property and then I'll apply it to +this node and because this is already + + align:start position:0% +this node and because this is already + + + align:start position:0% +this node and because this is already +correct by induction and this is already + + align:start position:0% +correct by induction and this is already + + + align:start position:0% +correct by induction and this is already +correct because I didn't touch this + + align:start position:0% +correct because I didn't touch this + + + align:start position:0% +correct because I didn't touch this +subre it's unchanged then I can update + + align:start position:0% +subre it's unchanged then I can update + + + align:start position:0% +subre it's unchanged then I can update +the value at this node the property at + + align:start position:0% +the value at this node the property at + + + align:start position:0% +the value at this node the property at +this node in constant time then I update + + align:start position:0% +this node in constant time then I update + + + align:start position:0% +this node in constant time then I update +this one and because this one is already + + align:start position:0% +this one and because this one is already + + + align:start position:0% +this one and because this one is already +correct by induction and this one is + + align:start position:0% +correct by induction and this one is + + + align:start position:0% +correct by induction and this one is +already correct because this sub tree is + + align:start position:0% +already correct because this sub tree is + + + align:start position:0% +already correct because this sub tree is +unchanged I can update the property + + align:start position:0% +unchanged I can update the property + + + align:start position:0% +unchanged I can update the property +correctly here in constant time okay so + + align:start position:0% +correctly here in constant time okay so + + + align:start position:0% +correctly here in constant time okay so +when I make a change in order H time + + align:start position:0% +when I make a change in order H time + + + align:start position:0% +when I make a change in order H time +because I'm making H calls to this + + align:start position:0% +because I'm making H calls to this + + + align:start position:0% +because I'm making H calls to this +constant time algorithm I can update a + + align:start position:0% +constant time algorithm I can update a + + + align:start position:0% +constant time algorithm I can update a +constant number of sub tree + + align:start position:0% +constant number of sub tree + + + align:start position:0% +constant number of sub tree +properties this is very powerful data + + align:start position:0% +properties this is very powerful data + + + align:start position:0% +properties this is very powerful data +structure argumentation is super useful + + align:start position:0% +structure argumentation is super useful + + + align:start position:0% +structure argumentation is super useful +you will use it on your problem set we + + align:start position:0% +you will use it on your problem set we + + + align:start position:0% +you will use it on your problem set we +will use it again + + align:start position:0% +will use it again + + + align:start position:0% +will use it again +today let me give you some examples of + + align:start position:0% +today let me give you some examples of + + + align:start position:0% +today let me give you some examples of +sub tree + + align:start position:0% + + + + align:start position:0% + +properties they could would be uh common + + align:start position:0% +properties they could would be uh common + + + align:start position:0% +properties they could would be uh common +ones are like the sum or the product or + + align:start position:0% +ones are like the sum or the product or + + + align:start position:0% +ones are like the sum or the product or +the Min or the + + align:start position:0% + + + + align:start position:0% + +max or sum of squares or all sorts of + + align:start position:0% +max or sum of squares or all sorts of + + + align:start position:0% +max or sum of squares or all sorts of +things of + + align:start position:0% +things of + + + align:start position:0% +things of +some + + align:start position:0% + + + + align:start position:0% + +feature of every node in + + align:start position:0% + + + + align:start position:0% + +subtree okay in fact + + align:start position:0% +subtree okay in fact + + + align:start position:0% +subtree okay in fact +uh sub tree size is an example of such a + + align:start position:0% +uh sub tree size is an example of such a + + + align:start position:0% +uh sub tree size is an example of such a +thing it is the sum over all nodes in + + align:start position:0% +thing it is the sum over all nodes in + + + align:start position:0% +thing it is the sum over all nodes in +the sub tree of the value one okay + + align:start position:0% +the sub tree of the value one okay + + + align:start position:0% +the sub tree of the value one okay +that's another way to say count the + + align:start position:0% +that's another way to say count the + + + align:start position:0% +that's another way to say count the +number of nodes okay but you could also + + align:start position:0% +number of nodes okay but you could also + + + align:start position:0% +number of nodes okay but you could also +say what's the sum of the keys in these + + align:start position:0% +say what's the sum of the keys in these + + + align:start position:0% +say what's the sum of the keys in these +nodes or you could say what's the + + align:start position:0% +nodes or you could say what's the + + + align:start position:0% +nodes or you could say what's the +maximum key in these nodes or you could + + align:start position:0% +maximum key in these nodes or you could + + + align:start position:0% +maximum key in these nodes or you could +say + + align:start position:0% +say + + + align:start position:0% +say +uh um what is the + + align:start position:0% +uh um what is the + + + align:start position:0% +uh um what is the +maximum value in these notes you can + + align:start position:0% +maximum value in these notes you can + + + align:start position:0% +maximum value in these notes you can +take any property it doesn't have to be + + align:start position:0% +take any property it doesn't have to be + + + align:start position:0% +take any property it doesn't have to be +key it doesn't have to be anything in + + align:start position:0% +key it doesn't have to be anything in + + + align:start position:0% +key it doesn't have to be anything in +particular it's very powerful you can + + align:start position:0% +particular it's very powerful you can + + + align:start position:0% +particular it's very powerful you can +take all sums products and Main maintain + + align:start position:0% +take all sums products and Main maintain + + + align:start position:0% +take all sums products and Main maintain +them as long as they're downward looking + + align:start position:0% +them as long as they're downward looking + + + align:start position:0% +them as long as they're downward looking +as long as you're only thinking about + + align:start position:0% +as long as you're only thinking about + + + align:start position:0% +as long as you're only thinking about +the sub + + align:start position:0% +the sub + + + align:start position:0% +the sub +tree okay uh some examples of things you + + align:start position:0% +tree okay uh some examples of things you + + + align:start position:0% +tree okay uh some examples of things you +cannot + + align:start position:0% +cannot + + + align:start position:0% +cannot +maintain + + align:start position:0% + + + + align:start position:0% + +are + + align:start position:0% +are + + + align:start position:0% +are +not a nodes + + align:start position:0% + + + + align:start position:0% + +index so if you get a little bit too + + align:start position:0% +index so if you get a little bit too + + + align:start position:0% +index so if you get a little bit too +excited about augmentation you might + + align:start position:0% +excited about augmentation you might + + + align:start position:0% +excited about augmentation you might +think oh it could do everything right I + + align:start position:0% +think oh it could do everything right I + + + align:start position:0% +think oh it could do everything right I +needed to support subtree at or let's + + align:start position:0% +needed to support subtree at or let's + + + align:start position:0% +needed to support subtree at or let's +just say uh get at globally I wanted to + + align:start position:0% +just say uh get at globally I wanted to + + + align:start position:0% +just say uh get at globally I wanted to +know what is the I node in my tree well + + align:start position:0% +know what is the I node in my tree well + + + align:start position:0% +know what is the I node in my tree well +I'll just use data structure + + align:start position:0% +I'll just use data structure + + + align:start position:0% +I'll just use data structure +augumentation and store in every node + + align:start position:0% +augumentation and store in every node + + + align:start position:0% +augumentation and store in every node +what is its index zero through n minus + + align:start position:0% +what is its index zero through n minus + + + align:start position:0% +what is its index zero through n minus +one I can't maintain that efficiently + + align:start position:0% +one I can't maintain that efficiently + + + align:start position:0% +one I can't maintain that efficiently +because if I insert at the beginning of + + align:start position:0% +because if I insert at the beginning of + + + align:start position:0% +because if I insert at the beginning of +my traversal order then all the indices + + align:start position:0% +my traversal order then all the indices + + + align:start position:0% +my traversal order then all the indices +change right so that that's an example + + align:start position:0% +change right so that that's an example + + + align:start position:0% +change right so that that's an example +of a of a edit so if I insert a new Noe + + align:start position:0% +of a of a edit so if I insert a new Noe + + + align:start position:0% +of a of a edit so if I insert a new Noe +over here so this guy's index was Zero + + align:start position:0% +over here so this guy's index was Zero + + + align:start position:0% +over here so this guy's index was Zero +now it's one this guy's index was one + + align:start position:0% +now it's one this guy's index was one + + + align:start position:0% +now it's one this guy's index was one +now it's two this was two two now it's + + align:start position:0% +now it's two this was two two now it's + + + align:start position:0% +now it's two this was two two now it's +three and so on every node changes its + + align:start position:0% +three and so on every node changes its + + + align:start position:0% +three and so on every node changes its +index index is not a subtree property + + align:start position:0% +index index is not a subtree property + + + align:start position:0% +index index is not a subtree property +and that's why we can't maintain it + + align:start position:0% +and that's why we can't maintain it + + + align:start position:0% +and that's why we can't maintain it +because it depends on all of the nodes + + align:start position:0% +because it depends on all of the nodes + + + align:start position:0% +because it depends on all of the nodes +in the tree or it depends on all the + + align:start position:0% +in the tree or it depends on all the + + + align:start position:0% +in the tree or it depends on all the +nodes to its left all the predecessors + + align:start position:0% +nodes to its left all the predecessors + + + align:start position:0% +nodes to its left all the predecessors +so for example this guy's index depends + + align:start position:0% +so for example this guy's index depends + + + align:start position:0% +so for example this guy's index depends +on how many nodes are over here on the + + align:start position:0% +on how many nodes are over here on the + + + align:start position:0% +on how many nodes are over here on the +left which is not in the sub tree of + + align:start position:0% +left which is not in the sub tree of + + + align:start position:0% +left which is not in the sub tree of +that Noe so that's where you have to be + + align:start position:0% +that Noe so that's where you have to be + + + align:start position:0% +that Noe so that's where you have to be +careful don't use Global properties of + + align:start position:0% +careful don't use Global properties of + + + align:start position:0% +careful don't use Global properties of +the tree you can only use + + align:start position:0% +the tree you can only use + + + align:start position:0% +the tree you can only use +subtree sub tree + + align:start position:0% +subtree sub tree + + + align:start position:0% +subtree sub tree +properties okay another example is uh + + align:start position:0% +properties okay another example is uh + + + align:start position:0% +properties okay another example is uh +depth depth is annoying to + + align:start position:0% +depth depth is annoying to + + + align:start position:0% +depth depth is annoying to +maintain uh but it's not obvious why yet + + align:start position:0% +maintain uh but it's not obvious why yet + + + align:start position:0% +maintain uh but it's not obvious why yet +we will see that in a + + align:start position:0% + + + + align:start position:0% + +moment okay the rest of today is about + + align:start position:0% +moment okay the rest of today is about + + + align:start position:0% +moment okay the rest of today is about +going from order H to order log n which + + align:start position:0% +going from order H to order log n which + + + align:start position:0% +going from order H to order log n which +is what this slide is showing us so at + + align:start position:0% +is what this slide is showing us so at + + + align:start position:0% +is what this slide is showing us so at +this point you should believe that we + + align:start position:0% +this point you should believe that we + + + align:start position:0% +this point you should believe that we +can do all of the sequence data + + align:start position:0% +can do all of the sequence data + + + align:start position:0% +can do all of the sequence data +structure operations in order H time + + align:start position:0% +structure operations in order H time + + + align:start position:0% +structure operations in order H time +except for build and iterate which take + + align:start position:0% +except for build and iterate which take + + + align:start position:0% +except for build and iterate which take +linear time uh and that we can do all of + + align:start position:0% +linear time uh and that we can do all of + + + align:start position:0% +linear time uh and that we can do all of +the set operations in order H time + + align:start position:0% +the set operations in order H time + + + align:start position:0% +the set operations in order H time +except build and iterate which Take N + + align:start position:0% +except build and iterate which Take N + + + align:start position:0% +except build and iterate which Take N +log n and n respectively and our goal is + + align:start position:0% +log n and n respectively and our goal is + + + align:start position:0% +log n and n respectively and our goal is +to now + + align:start position:0% +to now + + + align:start position:0% +to now +bound + + align:start position:0% + + + + align:start position:0% + +uh H by log n we know it's possible at + + align:start position:0% +uh H by log n we know it's possible at + + + align:start position:0% +uh H by log n we know it's possible at +some level because there are + + align:start position:0% +some level because there are + + + align:start position:0% +some level because there are +trees that have logarithmic height + + align:start position:0% +trees that have logarithmic height + + + align:start position:0% +trees that have logarithmic height +that's like this Perfect Tree + + align:start position:0% +that's like this Perfect Tree + + + align:start position:0% +that's like this Perfect Tree +here but we also know we have to be + + align:start position:0% +here but we also know we have to be + + + align:start position:0% +here but we also know we have to be +careful because there are some bad trees + + align:start position:0% +careful because there are some bad trees + + + align:start position:0% +careful because there are some bad trees +like this + + align:start position:0% + + + + align:start position:0% + +chain so + + align:start position:0% +chain so + + + align:start position:0% +chain so +um if H equals log n we call this a + + align:start position:0% +um if H equals log n we call this a + + + align:start position:0% +um if H equals log n we call this a +balanced binary + + align:start position:0% + + + + align:start position:0% + +tree there are many balanced binary + + align:start position:0% +tree there are many balanced binary + + + align:start position:0% +tree there are many balanced binary +trees in the world maybe a dozen or + + align:start position:0% +trees in the world maybe a dozen or + + + align:start position:0% +trees in the world maybe a dozen or +two a lot of different data structures + + align:start position:0% +two a lot of different data structures + + + align:start position:0% +two a lot of different data structures +question hi you um you said like not to + + align:start position:0% +question hi you um you said like not to + + + align:start position:0% +question hi you um you said like not to +think about things on a global level + + align:start position:0% +think about things on a global level + + + align:start position:0% +think about things on a global level +think of them at a sub level can you + + align:start position:0% +think of them at a sub level can you + + + align:start position:0% +think of them at a sub level can you +explain what + + align:start position:0% +explain what + + + align:start position:0% +explain what +that okay what does it mean for property + + align:start position:0% +that okay what does it mean for property + + + align:start position:0% +that okay what does it mean for property +to be uh local to a sub tree versus + + align:start position:0% +to be uh local to a sub tree versus + + + align:start position:0% +to be uh local to a sub tree versus +global the best answer is this + + align:start position:0% +global the best answer is this + + + align:start position:0% +global the best answer is this +definition but that's maybe not the most + + align:start position:0% +definition but that's maybe not the most + + + align:start position:0% +definition but that's maybe not the most +intuitive definition this is what I mean + + align:start position:0% +intuitive definition this is what I mean + + + align:start position:0% +intuitive definition this is what I mean +something that can be computed just + + align:start position:0% +something that can be computed just + + + align:start position:0% +something that can be computed just +knowing information about your left and + + align:start position:0% +knowing information about your left and + + + align:start position:0% +knowing information about your left and +right children that is the meaning of + + align:start position:0% +right children that is the meaning of + + + align:start position:0% +right children that is the meaning of +subre property and those are the only + + align:start position:0% +subre property and those are the only + + + align:start position:0% +subre property and those are the only +things you're allowed to maintain + + align:start position:0% +things you're allowed to maintain + + + align:start position:0% +things you're allowed to maintain +because those are the only + + align:start position:0% +because those are the only + + + align:start position:0% +because those are the only +things uh that are easy to update by + + align:start position:0% +things uh that are easy to update by + + + align:start position:0% +things uh that are easy to update by +walking up this path and the contrast is + + align:start position:0% +walking up this path and the contrast is + + + align:start position:0% +walking up this path and the contrast is +that a global property like + + align:start position:0% +that a global property like + + + align:start position:0% +that a global property like +index I it's Global in particular + + align:start position:0% +index I it's Global in particular + + + align:start position:0% +index I it's Global in particular +because I can do one change add one no + + align:start position:0% +because I can do one change add one no + + + align:start position:0% +because I can do one change add one no +node and all of the nodes properties + + align:start position:0% +node and all of the nodes properties + + + align:start position:0% +node and all of the nodes properties +change so that's an extreme example of + + align:start position:0% +change so that's an extreme example of + + + align:start position:0% +change so that's an extreme example of +global we want this very particular + + align:start position:0% +global we want this very particular + + + align:start position:0% +global we want this very particular +notion of + + align:start position:0% +notion of + + + align:start position:0% +notion of +local uh because that's what we can + + align:start position:0% +local uh because that's what we can + + + align:start position:0% +local uh because that's what we can +actually afford to recompute hopefully + + align:start position:0% +actually afford to recompute hopefully + + + align:start position:0% +actually afford to recompute hopefully +that clarifies + + align:start position:0% +that clarifies + + + align:start position:0% +that clarifies +yeah doesn't size + + align:start position:0% + + + + align:start position:0% + +you're right that if we added oh no + + align:start position:0% +you're right that if we added oh no + + + align:start position:0% +you're right that if we added oh no +let's okay let's think about that if we + + align:start position:0% +let's okay let's think about that if we + + + align:start position:0% +let's okay let's think about that if we +added a new parent to the tree this is + + align:start position:0% +added a new parent to the tree this is + + + align:start position:0% +added a new parent to the tree this is +not something that we've ever done um + + align:start position:0% +not something that we've ever done um + + + align:start position:0% +not something that we've ever done um +but even if we did that which sub trees + + align:start position:0% +but even if we did that which sub trees + + + align:start position:0% +but even if we did that which sub trees +change only this + + align:start position:0% +change only this + + + align:start position:0% +change only this +one right this node it's it's a new + + align:start position:0% +one right this node it's it's a new + + + align:start position:0% +one right this node it's it's a new +totally new sub tree but the sub tree of + + align:start position:0% +totally new sub tree but the sub tree of + + + align:start position:0% +totally new sub tree but the sub tree of +this node is completely unchanged + + align:start position:0% +this node is completely unchanged + + + align:start position:0% +this node is completely unchanged +because sub trees are always downward + + align:start position:0% +because sub trees are always downward + + + align:start position:0% +because sub trees are always downward +looking if I added a new root um I + + align:start position:0% +looking if I added a new root um I + + + align:start position:0% +looking if I added a new root um I +didn't change any sub except for one so + + align:start position:0% +didn't change any sub except for one so + + + align:start position:0% +didn't change any sub except for one so +size is a sube property now there are I + + align:start position:0% +size is a sube property now there are I + + + align:start position:0% +size is a sube property now there are I +mean I can completely redraw the tree + + align:start position:0% +mean I can completely redraw the tree + + + align:start position:0% +mean I can completely redraw the tree +and that's an operation that requires + + align:start position:0% +and that's an operation that requires + + + align:start position:0% +and that's an operation that requires +everything to be recomputed okay so it + + align:start position:0% +everything to be recomputed okay so it + + + align:start position:0% +everything to be recomputed okay so it +is limited exactly what I'm allowed to + + align:start position:0% +is limited exactly what I'm allowed to + + + align:start position:0% +is limited exactly what I'm allowed to +do in the tree but I claim everything + + align:start position:0% +do in the tree but I claim everything + + + align:start position:0% +do in the tree but I claim everything +will do last class and today uh we can + + align:start position:0% +will do last class and today uh we can + + + align:start position:0% +will do last class and today uh we can +afford this + + align:start position:0% +afford this + + + align:start position:0% +afford this +augmentation so it's a feature not of + + align:start position:0% +augmentation so it's a feature not of + + + align:start position:0% +augmentation so it's a feature not of +all binary trees necessarily but the + + align:start position:0% +all binary trees necessarily but the + + + align:start position:0% +all binary trees necessarily but the +ones that we would cover + + align:start position:0% +ones that we would cover + + + align:start position:0% +ones that we would cover +yeah what is a + + align:start position:0% +yeah what is a + + + align:start position:0% +yeah what is a +Min binary binary tree + + align:start position:0% + + + + align:start position:0% + +yeah okay let's uh this will make a + + align:start position:0% +yeah okay let's uh this will make a + + + align:start position:0% +yeah okay let's uh this will make a +little more sense in a moment when I say + + align:start position:0% +little more sense in a moment when I say + + + align:start position:0% +little more sense in a moment when I say +what we're actually going to do with + + align:start position:0% + + + + align:start position:0% + +trees we + + align:start position:0% +trees we + + + align:start position:0% +trees we +uh we need a new tool for manipulating a + + align:start position:0% +uh we need a new tool for manipulating a + + + align:start position:0% +uh we need a new tool for manipulating a +tree what we've done so far we've done + + align:start position:0% +tree what we've done so far we've done + + + align:start position:0% +tree what we've done so far we've done +some swapping of items and we did adding + + align:start position:0% +some swapping of items and we did adding + + + align:start position:0% +some swapping of items and we did adding +removing a leaf that's not enough we're + + align:start position:0% +removing a leaf that's not enough we're + + + align:start position:0% +removing a leaf that's not enough we're +going to need something else to let us + + align:start position:0% +going to need something else to let us + + + align:start position:0% +going to need something else to let us +guarantee logarithmic + + align:start position:0% +guarantee logarithmic + + + align:start position:0% +guarantee logarithmic +height and that's something else is + + align:start position:0% +height and that's something else is + + + align:start position:0% +height and that's something else is +called a + + align:start position:0% + + + + align:start position:0% + +rotation what does this something else + + align:start position:0% +rotation what does this something else + + + align:start position:0% +rotation what does this something else +need to do this is just a tool for + + align:start position:0% +need to do this is just a tool for + + + align:start position:0% +need to do this is just a tool for +rebalancing the tree so it should not + + align:start position:0% +rebalancing the tree so it should not + + + align:start position:0% +rebalancing the tree so it should not +change the data that's represented by + + align:start position:0% +change the data that's represented by + + + align:start position:0% +change the data that's represented by +the tree what is the data represented by + + align:start position:0% +the tree what is the data represented by + + + align:start position:0% +the tree what is the data represented by +the tree traversal order traversal order + + align:start position:0% +the tree traversal order traversal order + + + align:start position:0% +the tree traversal order traversal order +is sacran where not allowed to touch it + + align:start position:0% +is sacran where not allowed to touch it + + + align:start position:0% +is sacran where not allowed to touch it +it's already defined two different ways + + align:start position:0% +it's already defined two different ways + + + align:start position:0% +it's already defined two different ways +depending on whether you're using a set + + align:start position:0% +depending on whether you're using a set + + + align:start position:0% +depending on whether you're using a set +or sequence so we want to modify the + + align:start position:0% +or sequence so we want to modify the + + + align:start position:0% +or sequence so we want to modify the +tree in a way that doesn't modify the + + align:start position:0% +tree in a way that doesn't modify the + + + align:start position:0% +tree in a way that doesn't modify the +traversal order so this we're exploiting + + align:start position:0% +traversal order so this we're exploiting + + + align:start position:0% +traversal order so this we're exploiting +redundancy if you wrote down the + + align:start position:0% +redundancy if you wrote down the + + + align:start position:0% +redundancy if you wrote down the +traversal order in an array there's + + align:start position:0% +traversal order in an array there's + + + align:start position:0% +traversal order in an array there's +exactly one representation of a given + + align:start position:0% +exactly one representation of a given + + + align:start position:0% +exactly one representation of a given +order but in a tree there's many + + align:start position:0% +order but in a tree there's many + + + align:start position:0% +order but in a tree there's many +representations it could be a long line + + align:start position:0% +representations it could be a long line + + + align:start position:0% +representations it could be a long line +it could be a balanced thing they could + + align:start position:0% +it could be a balanced thing they could + + + align:start position:0% +it could be a balanced thing they could +represent the exact same order on the + + align:start position:0% +represent the exact same order on the + + + align:start position:0% +represent the exact same order on the +nodes if you label them right okay in + + align:start position:0% +nodes if you label them right okay in + + + align:start position:0% +nodes if you label them right okay in +fact they're exponentially many + + align:start position:0% +fact they're exponentially many + + + align:start position:0% +fact they're exponentially many +different representations of the same + + align:start position:0% +different representations of the same + + + align:start position:0% +different representations of the same +thing and we're going to exploit that + + align:start position:0% +thing and we're going to exploit that + + + align:start position:0% +thing and we're going to exploit that +the same + + align:start position:0% +the same + + + align:start position:0% +the same +order and Define this is just a thing + + align:start position:0% +order and Define this is just a thing + + + align:start position:0% +order and Define this is just a thing +you need to + + align:start position:0% + + + + align:start position:0% + +know me label a x b y + + align:start position:0% +know me label a x b y + + + align:start position:0% +know me label a x b y +c you can tell I've drawn this diagram + + align:start position:0% +c you can tell I've drawn this diagram + + + align:start position:0% +c you can tell I've drawn this diagram +before many many times this is a very + + align:start position:0% +before many many times this is a very + + + align:start position:0% +before many many times this is a very +powerful tool in all tree data + + align:start position:0% +powerful tool in all tree data + + + align:start position:0% +powerful tool in all tree data +structures which are most of data + + align:start position:0% +structures which are most of data + + + align:start position:0% +structures which are most of data +structures uh and they are called right + + align:start position:0% + + + + align:start position:0% + +rotate of Y and left rotate of + + align:start position:0% + + + + align:start position:0% + +x uh so if I have this tree which I'm + + align:start position:0% +x uh so if I have this tree which I'm + + + align:start position:0% +x uh so if I have this tree which I'm +just blackboxing some of the sub into + + align:start position:0% +just blackboxing some of the sub into + + + align:start position:0% +just blackboxing some of the sub into +little triangles if I have a node and it + + align:start position:0% +little triangles if I have a node and it + + + align:start position:0% +little triangles if I have a node and it +it has a left child then I'm allowed to + + align:start position:0% +it has a left child then I'm allowed to + + + align:start position:0% +it has a left child then I'm allowed to +right rotate this Edge which means take + + align:start position:0% +right rotate this Edge which means take + + + align:start position:0% +right rotate this Edge which means take +this Edge and go like this 90 Dees kind + + align:start position:0% +this Edge and go like this 90 Dees kind + + + align:start position:0% +this Edge and go like this 90 Dees kind +of uh or you could just think of it as + + align:start position:0% +of uh or you could just think of it as + + + align:start position:0% +of uh or you could just think of it as +rewriting it this way now you might also + + align:start position:0% +rewriting it this way now you might also + + + align:start position:0% +rewriting it this way now you might also +keep in track of the parent pointer + + align:start position:0% +keep in track of the parent pointer + + + align:start position:0% +keep in track of the parent pointer +parent pointer uh moves around before + + align:start position:0% +parent pointer uh moves around before + + + align:start position:0% +parent pointer uh moves around before +this was the parent of Y now it's the + + align:start position:0% +this was the parent of Y now it's the + + + align:start position:0% +this was the parent of Y now it's the +parent of + + align:start position:0% +parent of + + + align:start position:0% +parent of +X okay so we X and Y are switching + + align:start position:0% +X okay so we X and Y are switching + + + align:start position:0% +X okay so we X and Y are switching +places but if we we couldn't just swap + + align:start position:0% +places but if we we couldn't just swap + + + align:start position:0% +places but if we we couldn't just swap +these items around that would change + + align:start position:0% +these items around that would change + + + align:start position:0% +these items around that would change +traversal order in this picture X comes + + align:start position:0% +traversal order in this picture X comes + + + align:start position:0% +traversal order in this picture X comes +before y because X is in the left sub + + align:start position:0% +before y because X is in the left sub + + + align:start position:0% +before y because X is in the left sub +tree of Y in traversal order and over + + align:start position:0% +tree of Y in traversal order and over + + + align:start position:0% +tree of Y in traversal order and over +here now Y is in the right sub tree of X + + align:start position:0% +here now Y is in the right sub tree of X + + + align:start position:0% +here now Y is in the right sub tree of X +so it comes after X so in both cases X + + align:start position:0% +so it comes after X so in both cases X + + + align:start position:0% +so it comes after X so in both cases X +comes before Y and indeed in all of + + align:start position:0% +comes before Y and indeed in all of + + + align:start position:0% +comes before Y and indeed in all of +these + + align:start position:0% +these + + + align:start position:0% +these +pictures uh the traversal order I mean + + align:start position:0% +pictures uh the traversal order I mean + + + align:start position:0% +pictures uh the traversal order I mean +not just for X and Y but also for a b + + align:start position:0% +not just for X and Y but also for a b + + + align:start position:0% +not just for X and Y but also for a b +and c the traversal order is consistent + + align:start position:0% +and c the traversal order is consistent + + + align:start position:0% +and c the traversal order is consistent +it is + + align:start position:0% +it is + + + align:start position:0% +it is +a uh x b + + align:start position:0% +a uh x b + + + align:start position:0% +a uh x b +y c where when I write a triangle I mean + + align:start position:0% +y c where when I write a triangle I mean + + + align:start position:0% +y c where when I write a triangle I mean +recursively the traversal order of all + + align:start position:0% +recursively the traversal order of all + + + align:start position:0% +recursively the traversal order of all +the things in the Triangle so if you + + align:start position:0% +the things in the Triangle so if you + + + align:start position:0% +the things in the Triangle so if you +just apply the traversal order algorithm + + align:start position:0% +just apply the traversal order algorithm + + + align:start position:0% +just apply the traversal order algorithm +here versus here you get the same output + + align:start position:0% +here versus here you get the same output + + + align:start position:0% +here versus here you get the same output +which means these these operations + + align:start position:0% +which means these these operations + + + align:start position:0% +which means these these operations +preserve traversal + + align:start position:0% + + + + align:start position:0% + +order great so this is a thing that we + + align:start position:0% +order great so this is a thing that we + + + align:start position:0% +order great so this is a thing that we +can do in a tree that won't affect any + + align:start position:0% +can do in a tree that won't affect any + + + align:start position:0% +can do in a tree that won't affect any +of the stuff we've done so far it's a + + align:start position:0% +of the stuff we've done so far it's a + + + align:start position:0% +of the stuff we've done so far it's a +tool that we can used to rebalance + + align:start position:0% +tool that we can used to rebalance + + + align:start position:0% +tool that we can used to rebalance +notice + + align:start position:0% +notice + + + align:start position:0% +notice +um you know how deep things are in the + + align:start position:0% +um you know how deep things are in the + + + align:start position:0% +um you know how deep things are in the +tree changes our problem with this + + align:start position:0% +tree changes our problem with this + + + align:start position:0% +tree changes our problem with this +linear tree is that there are some nodes + + align:start position:0% +linear tree is that there are some nodes + + + align:start position:0% +linear tree is that there are some nodes +of linear depth we want to get rid of + + align:start position:0% +of linear depth we want to get rid of + + + align:start position:0% +of linear depth we want to get rid of +those how we could take these edges and + + align:start position:0% +those how we could take these edges and + + + align:start position:0% +those how we could take these edges and +start rotating them up if you look at + + align:start position:0% +start rotating them up if you look at + + + align:start position:0% +start rotating them up if you look at +depths um you know in this picture A and + + align:start position:0% +depths um you know in this picture A and + + + align:start position:0% +depths um you know in this picture A and +B are deeper than C and in this picture + + align:start position:0% +B are deeper than C and in this picture + + + align:start position:0% +B are deeper than C and in this picture +uh B and C are deeper than a so you know + + align:start position:0% +uh B and C are deeper than a so you know + + + align:start position:0% +uh B and C are deeper than a so you know +there a trade-off this one moved up this + + align:start position:0% +there a trade-off this one moved up this + + + align:start position:0% +there a trade-off this one moved up this +one moved down this one stayed at the + + align:start position:0% +one moved down this one stayed at the + + + align:start position:0% +one moved down this one stayed at the +same + + align:start position:0% +same + + + align:start position:0% +same +depth so hopefully if if a is too deep + + align:start position:0% +depth so hopefully if if a is too deep + + + align:start position:0% +depth so hopefully if if a is too deep +and C is too shallow uh they can trade + + align:start position:0% +and C is too shallow uh they can trade + + + align:start position:0% +and C is too shallow uh they can trade +off like this okay it may sound + + align:start position:0% +off like this okay it may sound + + + align:start position:0% +off like this okay it may sound +difficult but in fact there's a pretty + + align:start position:0% +difficult but in fact there's a pretty + + + align:start position:0% +difficult but in fact there's a pretty +simple way uh which are called AVL + + align:start position:0% + + + + align:start position:0% + +trees uh that maintain balance in a + + align:start position:0% +trees uh that maintain balance in a + + + align:start position:0% +trees uh that maintain balance in a +particular + + align:start position:0% +particular + + + align:start position:0% +particular +way called height balance + + align:start position:0% + + + + align:start position:0% + +this is uh if we take the + + align:start position:0% +this is uh if we take the + + + align:start position:0% +this is uh if we take the +height of no dot + + align:start position:0% + + + + align:start position:0% + +left uh actually I'd prefer + + align:start position:0% +left uh actually I'd prefer + + + align:start position:0% +left uh actually I'd prefer +to no do + + align:start position:0% + + + + align:start position:0% + +right + + align:start position:0% +right + + + align:start position:0% +right +minus height of node do left + + align:start position:0% + + + + align:start position:0% + +so this thing is called um + + align:start position:0% +so this thing is called um + + + align:start position:0% +so this thing is called um +skew of the + + align:start position:0% +skew of the + + + align:start position:0% +skew of the +node I want this to always be minus1 0 + + align:start position:0% +node I want this to always be minus1 0 + + + align:start position:0% +node I want this to always be minus1 0 +or plus + + align:start position:0% +or plus + + + align:start position:0% +or plus +one okay so this is saying that if I + + align:start position:0% +one okay so this is saying that if I + + + align:start position:0% +one okay so this is saying that if I +have any node and I look if it's left + + align:start position:0% +have any node and I look if it's left + + + align:start position:0% +have any node and I look if it's left +sube and it's right sub tree I measure + + align:start position:0% +sube and it's right sub tree I measure + + + align:start position:0% +sube and it's right sub tree I measure +their heights remember that's downward + + align:start position:0% +their heights remember that's downward + + + align:start position:0% +their heights remember that's downward +dist to maximum distance to a leaf I + + align:start position:0% +dist to maximum distance to a leaf I + + + align:start position:0% +dist to maximum distance to a leaf I +measure the height of this tree maximum + + align:start position:0% +measure the height of this tree maximum + + + align:start position:0% +measure the height of this tree maximum +height I measure the maximum height of + + align:start position:0% +height I measure the maximum height of + + + align:start position:0% +height I measure the maximum height of +this sube I want these to be within one + + align:start position:0% +this sube I want these to be within one + + + align:start position:0% +this sube I want these to be within one +of each other maybe ideally they're + + align:start position:0% +of each other maybe ideally they're + + + align:start position:0% +of each other maybe ideally they're +equal that would be the perfect case but + + align:start position:0% +equal that would be the perfect case but + + + align:start position:0% +equal that would be the perfect case but +let's let them differ by one so maybe + + align:start position:0% +let's let them differ by one so maybe + + + align:start position:0% +let's let them differ by one so maybe +this is K and this is k + one or maybe + + align:start position:0% +this is K and this is k + one or maybe + + + align:start position:0% +this is K and this is k + one or maybe +this is K and this is K minus one what's + + align:start position:0% +this is K and this is K minus one what's + + + align:start position:0% +this is K and this is K minus one what's +the in this picture what is the height + + align:start position:0% +the in this picture what is the height + + + align:start position:0% +the in this picture what is the height +of this node it's good + + align:start position:0% +of this node it's good + + + align:start position:0% +of this node it's good +practice k+ 2 + + align:start position:0% +practice k+ 2 + + + align:start position:0% +practice k+ 2 +good what's the longest path from this + + align:start position:0% +good what's the longest path from this + + + align:start position:0% +good what's the longest path from this +node to a leaf well it could go through + + align:start position:0% +node to a leaf well it could go through + + + align:start position:0% +node to a leaf well it could go through +this sub tree and that would be length + + align:start position:0% +this sub tree and that would be length + + + align:start position:0% +this sub tree and that would be length +k+ 1 cuz it's K in here plus one for + + align:start position:0% +k+ 1 cuz it's K in here plus one for + + + align:start position:0% +k+ 1 cuz it's K in here plus one for +this Edge or it could be through here + + align:start position:0% +this Edge or it could be through here + + + align:start position:0% +this Edge or it could be through here +and that's k+ 1 plus one so the biggest + + align:start position:0% +and that's k+ 1 plus one so the biggest + + + align:start position:0% +and that's k+ 1 plus one so the biggest +is to go to the right so the height if I + + align:start position:0% +is to go to the right so the height if I + + + align:start position:0% +is to go to the right so the height if I +told you the height of these sub trees + + align:start position:0% +told you the height of these sub trees + + + align:start position:0% +told you the height of these sub trees +we can derive the height of this note + + align:start position:0% +we can derive the height of this note + + + align:start position:0% +we can derive the height of this note +we're going to use that a lot in a + + align:start position:0% +we're going to use that a lot in a + + + align:start position:0% +we're going to use that a lot in a +moment so first claim is that if I could + + align:start position:0% +moment so first claim is that if I could + + + align:start position:0% +moment so first claim is that if I could +maintain height balance then I + + align:start position:0% +maintain height balance then I + + + align:start position:0% +maintain height balance then I +can uh I will guarantee that H equals + + align:start position:0% +can uh I will guarantee that H equals + + + align:start position:0% +can uh I will guarantee that H equals +log n so in other words height balance + + align:start position:0% +log n so in other words height balance + + + align:start position:0% +log n so in other words height balance +implies + + align:start position:0% +implies + + + align:start position:0% +implies +balance so let's prove that + + align:start position:0% +balance so let's prove that + + + align:start position:0% +balance so let's prove that +first quickly and then the interesting + + align:start position:0% +first quickly and then the interesting + + + align:start position:0% +first quickly and then the interesting +part is how do we actually + + align:start position:0% + + + + align:start position:0% + +prove or how do we actually maintain the + + align:start position:0% +prove or how do we actually maintain the + + + align:start position:0% +prove or how do we actually maintain the +balance property we're going to do that + + align:start position:0% +balance property we're going to do that + + + align:start position:0% +balance property we're going to do that +using rotations but how is a big + + align:start position:0% +using rotations but how is a big + + + align:start position:0% +using rotations but how is a big +question + + align:start position:0% + + + + align:start position:0% + +okay so why does height + + align:start position:0% + + + + align:start position:0% + +balance imply + + align:start position:0% + + + + align:start position:0% + +balance so uh what this is saying is + + align:start position:0% +balance so uh what this is saying is + + + align:start position:0% +balance so uh what this is saying is +that all height balanc trees have + + align:start position:0% +that all height balanc trees have + + + align:start position:0% +that all height balanc trees have +logarithmic + + align:start position:0% +logarithmic + + + align:start position:0% +logarithmic +height so what I'd like to think about + + align:start position:0% +height so what I'd like to think about + + + align:start position:0% +height so what I'd like to think about +is sort of the Le least balanced height + + align:start position:0% +is sort of the Le least balanced height + + + align:start position:0% +is sort of the Le least balanced height +balanced tree uh the least balanced one + + align:start position:0% +balanced tree uh the least balanced one + + + align:start position:0% +balanced tree uh the least balanced one +is going to have at every node a + + align:start position:0% +is going to have at every node a + + + align:start position:0% +is going to have at every node a +mismatch the the left let's say the left + + align:start position:0% +mismatch the the left let's say the left + + + align:start position:0% +mismatch the the left let's say the left +sube is shallower than the right subtree + + align:start position:0% +sube is shallower than the right subtree + + + align:start position:0% +sube is shallower than the right subtree +by one and recursively all the way down + + align:start position:0% +by one and recursively all the way down + + + align:start position:0% +by one and recursively all the way down +so every node has a a Gap + + align:start position:0% +so every node has a a Gap + + + align:start position:0% +so every node has a a Gap +a + + align:start position:0% +a + + + align:start position:0% +a +uh what do we call it uh a skew of + + align:start position:0% +uh what do we call it uh a skew of + + + align:start position:0% +uh what do we call it uh a skew of +one okay which I'm going to write I'm + + align:start position:0% +one okay which I'm going to write I'm + + + align:start position:0% +one okay which I'm going to write I'm +going to introduce some notation I'll + + align:start position:0% +going to introduce some notation I'll + + + align:start position:0% +going to introduce some notation I'll +write a descending rightward Arrow if + + align:start position:0% +write a descending rightward Arrow if + + + align:start position:0% +write a descending rightward Arrow if +this one is is higher than the left sub + + align:start position:0% +this one is is higher than the left sub + + + align:start position:0% +this one is is higher than the left sub +tree uh so the easy way to think about + + align:start position:0% +tree uh so the easy way to think about + + + align:start position:0% +tree uh so the easy way to think about +this is this is sort of the our worst + + align:start position:0% +this is this is sort of the our worst + + + align:start position:0% +this is this is sort of the our worst +case this is going to be the the fewest + + align:start position:0% +case this is going to be the the fewest + + + align:start position:0% +case this is going to be the the fewest +nodes for the maximum depth let's just + + align:start position:0% +nodes for the maximum depth let's just + + + align:start position:0% +nodes for the maximum depth let's just +count how many nodes are in this + + align:start position:0% +count how many nodes are in this + + + align:start position:0% +count how many nodes are in this +tree I'm going to write that as a + + align:start position:0% +tree I'm going to write that as a + + + align:start position:0% +tree I'm going to write that as a +recurrence um which is the number of + + align:start position:0% +recurrence um which is the number of + + + align:start position:0% +recurrence um which is the number of +nodes in a tree of height + + align:start position:0% +nodes in a tree of height + + + align:start position:0% +nodes in a tree of height +H so if this whole tree has height h + + align:start position:0% + + + + align:start position:0% + +H uh as we said in this picture if I + + align:start position:0% +H uh as we said in this picture if I + + + align:start position:0% +H uh as we said in this picture if I +just subtract two from all these numbers + + align:start position:0% +just subtract two from all these numbers + + + align:start position:0% +just subtract two from all these numbers +then this one has height uh H minus 2 + + align:start position:0% +then this one has height uh H minus 2 + + + align:start position:0% +then this one has height uh H minus 2 +and this one has height H minus + + align:start position:0% +and this one has height H minus + + + align:start position:0% +and this one has height H minus +one okay so how many nodes are in here + + align:start position:0% +one okay so how many nodes are in here + + + align:start position:0% +one okay so how many nodes are in here +well this is a recurrence I'm going to + + align:start position:0% +well this is a recurrence I'm going to + + + align:start position:0% +well this is a recurrence I'm going to +write so this will be N Sub h-2 this + + align:start position:0% +write so this will be N Sub h-2 this + + + align:start position:0% +write so this will be N Sub h-2 this +will be N Sub + + align:start position:0% +will be N Sub + + + align:start position:0% +will be N Sub +hus1 and then I just count how many + + align:start position:0% +hus1 and then I just count how many + + + align:start position:0% +hus1 and then I just count how many +nodes are in this picture + + align:start position:0% +nodes are in this picture + + + align:start position:0% +nodes are in this picture +it is n subh -1 plus n subh - 2 + 1 or + + align:start position:0% +it is n subh -1 plus n subh - 2 + 1 or + + + align:start position:0% +it is n subh -1 plus n subh - 2 + 1 or +this note now you might ask what is NH + + align:start position:0% +this note now you might ask what is NH + + + align:start position:0% +this note now you might ask what is NH +or recurrence for uh but it is the + + align:start position:0% +or recurrence for uh but it is the + + + align:start position:0% +or recurrence for uh but it is the +number of nodes in this sort of worst + + align:start position:0% +number of nodes in this sort of worst + + + align:start position:0% +number of nodes in this sort of worst +case uh for if the worst case has total + + align:start position:0% +case uh for if the worst case has total + + + align:start position:0% +case uh for if the worst case has total +height H so you can also think of it as + + align:start position:0% +height H so you can also think of it as + + + align:start position:0% +height H so you can also think of it as +what is the minimum number of nodes I + + align:start position:0% +what is the minimum number of nodes I + + + align:start position:0% +what is the minimum number of nodes I +could have in an AVL tree which is a + + align:start position:0% +could have in an AVL tree which is a + + + align:start position:0% +could have in an AVL tree which is a +height balance tree uh that has height h + + align:start position:0% + + + + align:start position:0% + +in a height balanced + + align:start position:0% +in a height balanced + + + align:start position:0% +in a height balanced +tree okay so now I just need to solve + + align:start position:0% +tree okay so now I just need to solve + + + align:start position:0% +tree okay so now I just need to solve +this recurrence this recurrence look + + align:start position:0% + + + + align:start position:0% + +familiar + + align:start position:0% +familiar + + + align:start position:0% +familiar +is it's like Fibonacci numbers if I + + align:start position:0% +is it's like Fibonacci numbers if I + + + align:start position:0% +is it's like Fibonacci numbers if I +remove the plus one it's Fibonacci and + + align:start position:0% +remove the plus one it's Fibonacci and + + + align:start position:0% +remove the plus one it's Fibonacci and +if you happen to know the Fibonacci + + align:start position:0% +if you happen to know the Fibonacci + + + align:start position:0% +if you happen to know the Fibonacci +numbers grow as like a golden ratio to + + align:start position:0% +numbers grow as like a golden ratio to + + + align:start position:0% +numbers grow as like a golden ratio to +the N then we know that this is + + align:start position:0% +the N then we know that this is + + + align:start position:0% +the N then we know that this is +exponential which is what we want + + align:start position:0% +exponential which is what we want + + + align:start position:0% +exponential which is what we want +because if NH is exponential in h that + + align:start position:0% +because if NH is exponential in h that + + + align:start position:0% +because if NH is exponential in h that +means H is logarithmic in N because log + + align:start position:0% +means H is logarithmic in N because log + + + align:start position:0% +means H is logarithmic in N because log +is inverse of exponential okay but maybe + + align:start position:0% +is inverse of exponential okay but maybe + + + align:start position:0% +is inverse of exponential okay but maybe +you don't know about Fibonacci numbers + + align:start position:0% +you don't know about Fibonacci numbers + + + align:start position:0% +you don't know about Fibonacci numbers +and uh so we can still uh easily show + + align:start position:0% +and uh so we can still uh easily show + + + align:start position:0% +and uh so we can still uh easily show +that this is exponential as follows I + + align:start position:0% +that this is exponential as follows I + + + align:start position:0% +that this is exponential as follows I +want to prove that it's at least an + + align:start position:0% +want to prove that it's at least an + + + align:start position:0% +want to prove that it's at least an +exponential because that gives me that H + + align:start position:0% +exponential because that gives me that H + + + align:start position:0% +exponential because that gives me that H +is at most + + align:start position:0% +is at most + + + align:start position:0% +is at most +logarithmic um so we need a lower bound + + align:start position:0% +logarithmic um so we need a lower bound + + + align:start position:0% +logarithmic um so we need a lower bound +and so we have these two terms which are + + align:start position:0% +and so we have these two terms which are + + + align:start position:0% +and so we have these two terms which are +hard to compare n subh minus 1 and N Sub + + align:start position:0% +hard to compare n subh minus 1 and N Sub + + + align:start position:0% +hard to compare n subh minus 1 and N Sub +hus 2 it's kind of ugly uh but if we're + + align:start position:0% +hus 2 it's kind of ugly uh but if we're + + + align:start position:0% +hus 2 it's kind of ugly uh but if we're +allowed to be sloppy and we'll see if + + align:start position:0% +allowed to be sloppy and we'll see if + + + align:start position:0% +allowed to be sloppy and we'll see if +we're not too sloppy and still get an + + align:start position:0% +we're not too sloppy and still get an + + + align:start position:0% +we're not too sloppy and still get an +exponential answer um let's just make + + align:start position:0% +exponential answer um let's just make + + + align:start position:0% +exponential answer um let's just make +them + + align:start position:0% +them + + + align:start position:0% +them +equal uh like + + align:start position:0% +equal uh like + + + align:start position:0% +equal uh like +so + + align:start position:0% +so + + + align:start position:0% +so +um so this is a true statement in fact + + align:start position:0% +um so this is a true statement in fact + + + align:start position:0% +um so this is a true statement in fact +strictly greater than uh why because so + + align:start position:0% +strictly greater than uh why because so + + + align:start position:0% +strictly greater than uh why because so +I removed the plus one that should only + + align:start position:0% +I removed the plus one that should only + + + align:start position:0% +I removed the plus one that should only +make something smaller and um I replaced + + align:start position:0% +make something smaller and um I replaced + + + align:start position:0% +make something smaller and um I replaced +n subh minus1 with n subh minus 2 here + + align:start position:0% +n subh minus1 with n subh minus 2 here + + + align:start position:0% +n subh minus1 with n subh minus 2 here +I'm implic using a fact which is obvious + + align:start position:0% +I'm implic using a fact which is obvious + + + align:start position:0% +I'm implic using a fact which is obvious +by induction that uh this tree on height + + align:start position:0% +by induction that uh this tree on height + + + align:start position:0% +by induction that uh this tree on height +if I take this tree versus this tree + + align:start position:0% +if I take this tree versus this tree + + + align:start position:0% +if I take this tree versus this tree +this one has more nodes than this one + + align:start position:0% +this one has more nodes than this one + + + align:start position:0% +this one has more nodes than this one +right if I have larger height this + + align:start position:0% +right if I have larger height this + + + align:start position:0% +right if I have larger height this +construction is going to build a bigger + + align:start position:0% +construction is going to build a bigger + + + align:start position:0% +construction is going to build a bigger +tree at least as big doesn't need even + + align:start position:0% +tree at least as big doesn't need even + + + align:start position:0% +tree at least as big doesn't need even +need to be strictly bigger so certainly + + align:start position:0% +need to be strictly bigger so certainly + + + align:start position:0% +need to be strictly bigger so certainly +n subh minus one is greater than or + + align:start position:0% +n subh minus one is greater than or + + + align:start position:0% +n subh minus one is greater than or +equal to n subh minus 2 now this is 2 * + + align:start position:0% +equal to n subh minus 2 now this is 2 * + + + align:start position:0% +equal to n subh minus 2 now this is 2 * +n subus 2 and this is an easy recurrence + + align:start position:0% +n subus 2 and this is an easy recurrence + + + align:start position:0% +n subus 2 and this is an easy recurrence +this is just powers of two right I keep + + align:start position:0% +this is just powers of two right I keep + + + align:start position:0% +this is just powers of two right I keep +multiplying by two and subtracting two + + align:start position:0% +multiplying by two and subtracting two + + + align:start position:0% +multiplying by two and subtracting two +from H so this solves to 2 to the h 2 + + align:start position:0% +from H so this solves to 2 to the h 2 + + + align:start position:0% +from H so this solves to 2 to the h 2 +maybe with a floor or something okay but + + align:start position:0% +maybe with a floor or something okay but + + + align:start position:0% +maybe with a floor or something okay but +uh it is I'm using a base case here + + align:start position:0% +uh it is I'm using a base case here + + + align:start position:0% +uh it is I'm using a base case here +which is N Sub 0al + + align:start position:0% +which is N Sub 0al + + + align:start position:0% +which is N Sub 0al +1 uh maybe it's a ceiling then but the + + align:start position:0% +1 uh maybe it's a ceiling then but the + + + align:start position:0% +1 uh maybe it's a ceiling then but the +point is this is exponential so this + + align:start position:0% +point is this is exponential so this + + + align:start position:0% +point is this is exponential so this +implies that the height is always at + + align:start position:0% +implies that the height is always at + + + align:start position:0% +implies that the height is always at +most 2 * log + + align:start position:0% +most 2 * log + + + align:start position:0% +most 2 * log +n uh this two corresponds to this to if + + align:start position:0% +n uh this two corresponds to this to if + + + align:start position:0% +n uh this two corresponds to this to if +you just invert this formula this was + + align:start position:0% +you just invert this formula this was + + + align:start position:0% +you just invert this formula this was +number of nodes is going to be at + + align:start position:0% +number of nodes is going to be at + + + align:start position:0% +number of nodes is going to be at +least uh 2 the H2 and so H is at most to + + align:start position:0% +least uh 2 the H2 and so H is at most to + + + align:start position:0% +least uh 2 the H2 and so H is at most to +log n so it's not log n that would be + + align:start position:0% +log n so it's not log n that would be + + + align:start position:0% +log n so it's not log n that would be +perfect but it's within a factor of two + + align:start position:0% +perfect but it's within a factor of two + + + align:start position:0% +perfect but it's within a factor of two +of log n so AVL trees are always quite + + align:start position:0% +of log n so AVL trees are always quite + + + align:start position:0% +of log n so AVL trees are always quite +balanced number of levels is at most + + align:start position:0% +balanced number of levels is at most + + + align:start position:0% +balanced number of levels is at most +double what you need to store end nodes + + align:start position:0% + + + + align:start position:0% + +great we're left with the main Magic + + align:start position:0% +great we're left with the main Magic + + + align:start position:0% +great we're left with the main Magic +not domain magic that's different uh and + + align:start position:0% +not domain magic that's different uh and + + + align:start position:0% +not domain magic that's different uh and +let's see we're going to use subt tree + + align:start position:0% + + + + align:start position:0% + +augmentation keep + + align:start position:0% + + + + align:start position:0% + +that big remaining challenge is how do + + align:start position:0% +that big remaining challenge is how do + + + align:start position:0% +that big remaining challenge is how do +we maintain this height balance property + + align:start position:0% +we maintain this height balance property + + + align:start position:0% +we maintain this height balance property +using rotations we have all the + + align:start position:0% +using rotations we have all the + + + align:start position:0% +using rotations we have all the +ingredients lined up for us we have sub + + align:start position:0% +ingredients lined up for us we have sub + + + align:start position:0% +ingredients lined up for us we have sub +Tre + + align:start position:0% +Tre + + + align:start position:0% +Tre +augmentation what does that let me + + align:start position:0% + + + + align:start position:0% + +do that's relevant to AVL trees well it + + align:start position:0% +do that's relevant to AVL trees well it + + + align:start position:0% +do that's relevant to AVL trees well it +lets me store + + align:start position:0% +lets me store + + + align:start position:0% +lets me store +height right I need to be able to + + align:start position:0% +height right I need to be able to + + + align:start position:0% +height right I need to be able to +compute the height of a + + align:start position:0% +compute the height of a + + + align:start position:0% +compute the height of a +node that in general takes linear time + + align:start position:0% +node that in general takes linear time + + + align:start position:0% +node that in general takes linear time +because I have to look at all the + + align:start position:0% +because I have to look at all the + + + align:start position:0% +because I have to look at all the +downward paths all the leaves within + + align:start position:0% +downward paths all the leaves within + + + align:start position:0% +downward paths all the leaves within +that sub tree but height is a sub tree + + align:start position:0% +that sub tree but height is a sub tree + + + align:start position:0% +that sub tree but height is a sub tree +property so uh + + align:start position:0% +property so uh + + + align:start position:0% +property so uh +yes height + + align:start position:0% + + + + align:start position:0% + +why + + align:start position:0% +why + + + align:start position:0% +why +because uh let me just write it here + + align:start position:0% +because uh let me just write it here + + + align:start position:0% +because uh let me just write it here +node. + + align:start position:0% + + + + align:start position:0% + +height equals 1 + Max of node. left. + + align:start position:0% + + + + align:start position:0% + +height and no do right. + + align:start position:0% + + + + align:start position:0% + +height and of Max let me put this in a + + align:start position:0% +height and of Max let me put this in a + + + align:start position:0% +height and of Max let me put this in a +box + + align:start position:0% +box + + + align:start position:0% +box +this equation or I guess it's an + + align:start position:0% +this equation or I guess it's an + + + align:start position:0% +this equation or I guess it's an +assignment operation this is a + + align:start position:0% +assignment operation this is a + + + align:start position:0% +assignment operation this is a +one is the thing we've been doing over + + align:start position:0% +one is the thing we've been doing over + + + align:start position:0% +one is the thing we've been doing over +and over when I said what is the height + + align:start position:0% +and over when I said what is the height + + + align:start position:0% +and over when I said what is the height +of this node you just figured that out + + align:start position:0% +of this node you just figured that out + + + align:start position:0% +of this node you just figured that out +right you took the height of the left + + align:start position:0% +right you took the height of the left + + + align:start position:0% +right you took the height of the left +sub tree maxed with the height of the + + align:start position:0% +sub tree maxed with the height of the + + + align:start position:0% +sub tree maxed with the height of the +right sub tree and added one for to + + align:start position:0% +right sub tree and added one for to + + + align:start position:0% +right sub tree and added one for to +count for these edges okay so this is a + + align:start position:0% +count for these edges okay so this is a + + + align:start position:0% +count for these edges okay so this is a +general update rule it matches this + + align:start position:0% +general update rule it matches this + + + align:start position:0% +general update rule it matches this +subtree property pattern if I have the + + align:start position:0% +subtree property pattern if I have the + + + align:start position:0% +subtree property pattern if I have the +property of left and right I can compute + + align:start position:0% +property of left and right I can compute + + + align:start position:0% +property of left and right I can compute +it for node + + align:start position:0% +it for node + + + align:start position:0% +it for node +and this takes constant time to do and + + align:start position:0% +and this takes constant time to do and + + + align:start position:0% +and this takes constant time to do and +so it's a sub tree property and so I can + + align:start position:0% +so it's a sub tree property and so I can + + + align:start position:0% +so it's a sub tree property and so I can +maintain through all the things I'm + + align:start position:0% +maintain through all the things I'm + + + align:start position:0% +maintain through all the things I'm +doing the height of every node oh by the + + align:start position:0% +doing the height of every node oh by the + + + align:start position:0% +doing the height of every node oh by the +way whenever I do a rotation I'm also + + align:start position:0% +way whenever I do a rotation I'm also + + + align:start position:0% +way whenever I do a rotation I'm also +going to have to update my sube + + align:start position:0% +going to have to update my sube + + + align:start position:0% +going to have to update my sube +properties when I rotate this Edge a + + align:start position:0% +properties when I rotate this Edge a + + + align:start position:0% +properties when I rotate this Edge a +does not change B does not change C does + + align:start position:0% +does not change B does not change C does + + + align:start position:0% +does not change B does not change C does +not change so that's good but X's sub + + align:start position:0% +not change so that's good but X's sub + + + align:start position:0% +not change so that's good but X's sub +tree changes it now has why it didn't + + align:start position:0% +tree changes it now has why it didn't + + + align:start position:0% +tree changes it now has why it didn't +before so we're going to have to also uh + + align:start position:0% +before so we're going to have to also uh + + + align:start position:0% +before so we're going to have to also uh +update the augmentation here + + align:start position:0% +update the augmentation here + + + align:start position:0% +update the augmentation here +Y and we're going to have to update the + + align:start position:0% +Y and we're going to have to update the + + + align:start position:0% +Y and we're going to have to update the +augmentation in + + align:start position:0% +augmentation in + + + align:start position:0% +augmentation in +X and we're going to have to update the + + align:start position:0% +X and we're going to have to update the + + + align:start position:0% +X and we're going to have to update the +augmentation of all of the ancestors of + + align:start position:0% +augmentation of all of the ancestors of + + + align:start position:0% +augmentation of all of the ancestors of +X eventually um so rotation is locally + + align:start position:0% +X eventually um so rotation is locally + + + align:start position:0% +X eventually um so rotation is locally +just changing a constant number of + + align:start position:0% +just changing a constant number of + + + align:start position:0% +just changing a constant number of +pointers so I usually think of rotations + + align:start position:0% +pointers so I usually think of rotations + + + align:start position:0% +pointers so I usually think of rotations +as taking constant + + align:start position:0% +as taking constant + + + align:start position:0% +as taking constant +time uh but eventually we will have to + + align:start position:0% +time uh but eventually we will have to + + + align:start position:0% +time uh but eventually we will have to +do this is constant time + + align:start position:0% +do this is constant time + + + align:start position:0% +do this is constant time +locally + + align:start position:0% +locally + + + align:start position:0% +locally +uh but we will need to up + + align:start position:0% + + + + align:start position:0% + +uh H + + align:start position:0% +uh H + + + align:start position:0% +uh H +ancestors in order to store all of keep + + align:start position:0% +ancestors in order to store all of keep + + + align:start position:0% +ancestors in order to store all of keep +all of our augmentations up to date okay + + align:start position:0% +all of our augmentations up to date okay + + + align:start position:0% +all of our augmentations up to date okay +we'll worry about that + + align:start position:0% + + + + align:start position:0% + +later all right so great now we have the + + align:start position:0% +later all right so great now we have the + + + align:start position:0% +later all right so great now we have the +height of all the nodes we can compute + + align:start position:0% +height of all the nodes we can compute + + + align:start position:0% +height of all the nodes we can compute +the SK skew of all the nodes cool uh we + + align:start position:0% +the SK skew of all the nodes cool uh we + + + align:start position:0% +the SK skew of all the nodes cool uh we +have this rotation operation and we want + + align:start position:0% +have this rotation operation and we want + + + align:start position:0% +have this rotation operation and we want +to + + align:start position:0% +to + + + align:start position:0% +to +maintain + + align:start position:0% +maintain + + + align:start position:0% +maintain +uh this height balance property height + + align:start position:0% +uh this height balance property height + + + align:start position:0% +uh this height balance property height +of left node left and right of every + + align:start position:0% +of left node left and right of every + + + align:start position:0% +of left node left and right of every +node is within is plus or minus one or + + align:start position:0% +node is within is plus or minus one or + + + align:start position:0% +node is within is plus or minus one or +zero + + align:start position:0% +zero + + + align:start position:0% +zero +um + + align:start position:0% +um + + + align:start position:0% +um +cool so uh I said over here + + align:start position:0% +cool so uh I said over here + + + align:start position:0% +cool so uh I said over here +somewhere whenever we so the only things + + align:start position:0% +somewhere whenever we so the only things + + + align:start position:0% +somewhere whenever we so the only things +that change the tree are when we insert + + align:start position:0% +that change the tree are when we insert + + + align:start position:0% +that change the tree are when we insert +or delete a new node and it and the way + + align:start position:0% +or delete a new node and it and the way + + + align:start position:0% +or delete a new node and it and the way +that we implemented those so far is to + + align:start position:0% +that we implemented those so far is to + + + align:start position:0% +that we implemented those so far is to +add or remove a leaf so we should still + + align:start position:0% +add or remove a leaf so we should still + + + align:start position:0% +add or remove a leaf so we should still +be thinking about adding or removing a + + align:start position:0% +be thinking about adding or removing a + + + align:start position:0% +be thinking about adding or removing a +leaf the problem is when I add a new + + align:start position:0% +leaf the problem is when I add a new + + + align:start position:0% +leaf the problem is when I add a new +Leaf + + align:start position:0% +Leaf + + + align:start position:0% +Leaf +now maybe this tree is higher than it + + align:start position:0% +now maybe this tree is higher than it + + + align:start position:0% +now maybe this tree is higher than it +used to be so um some node here may no + + align:start position:0% +used to be so um some node here may no + + + align:start position:0% +used to be so um some node here may no +longer be height balanced but because + + align:start position:0% +longer be height balanced but because + + + align:start position:0% +longer be height balanced but because +height is a subtree property the only + + align:start position:0% +height is a subtree property the only + + + align:start position:0% +height is a subtree property the only +nodes we need to check are the ones up + + align:start position:0% +nodes we need to check are the ones up + + + align:start position:0% +nodes we need to check are the ones up +this ancestor path so and there's only + + align:start position:0% +this ancestor path so and there's only + + + align:start position:0% +this ancestor path so and there's only +log n of them because now height is log + + align:start position:0% +log n of them because now height is log + + + align:start position:0% +log n of them because now height is log +n that's what we just proved as long as + + align:start position:0% +n that's what we just proved as long as + + + align:start position:0% +n that's what we just proved as long as +we have this property now we right now + + align:start position:0% +we have this property now we right now + + + align:start position:0% +we have this property now we right now +don't have it for like maybe these few + + align:start position:0% +don't have it for like maybe these few + + + align:start position:0% +don't have it for like maybe these few +notes but it will be it was log n before + + align:start position:0% +notes but it will be it was log n before + + + align:start position:0% +notes but it will be it was log n before +it's at most log n 2 log n plus one + + align:start position:0% +it's at most log n 2 log n plus one + + + align:start position:0% +it's at most log n 2 log n plus one +right now cuz we just added a Noe + + align:start position:0% +right now cuz we just added a Noe + + + align:start position:0% +right now cuz we just added a Noe +so what I want to do is check all of + + align:start position:0% +so what I want to do is check all of + + + align:start position:0% +so what I want to do is check all of +these ancestor nodes in sequence from + + align:start position:0% +these ancestor nodes in sequence from + + + align:start position:0% +these ancestor nodes in sequence from +bottom up and find one that's out of + + align:start position:0% +bottom up and find one that's out of + + + align:start position:0% +bottom up and find one that's out of +balance so let's take the + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +lowest uh outof balance + + align:start position:0% + + + + align:start position:0% + +node I'm going to call that X now + + align:start position:0% +node I'm going to call that X now + + + align:start position:0% +node I'm going to call that X now +because we just inserted or deleted a + + align:start position:0% +because we just inserted or deleted a + + + align:start position:0% +because we just inserted or deleted a +single leaf it's only out of balance by + + align:start position:0% +single leaf it's only out of balance by + + + align:start position:0% +single leaf it's only out of balance by +one right because we only changed height + + align:start position:0% +one right because we only changed height + + + align:start position:0% +one right because we only changed height +one height went up by one or one height + + align:start position:0% +one height went up by one or one height + + + align:start position:0% +one height went up by one or one height +went down by one and before all of our + + align:start position:0% +went down by one and before all of our + + + align:start position:0% +went down by one and before all of our +SKS were plus or minus one or zero so + + align:start position:0% +SKS were plus or minus one or zero so + + + align:start position:0% +SKS were plus or minus one or zero so +now it's going the bad case is when it's + + align:start position:0% +now it's going the bad case is when it's + + + align:start position:0% +now it's going the bad case is when it's +plus or minus two if it happens to still + + align:start position:0% +plus or minus two if it happens to still + + + align:start position:0% +plus or minus two if it happens to still +be in this range for all the nodes we're + + align:start position:0% +be in this range for all the nodes we're + + + align:start position:0% +be in this range for all the nodes we're +happy but if it's outside this range + + align:start position:0% +happy but if it's outside this range + + + align:start position:0% +happy but if it's outside this range +it's only going to be out by one uh so + + align:start position:0% +it's only going to be out by one uh so + + + align:start position:0% +it's only going to be out by one uh so +this means the + + align:start position:0% +this means the + + + align:start position:0% +this means the +skew is in plus 2 orus + + align:start position:0% +skew is in plus 2 orus + + + align:start position:0% +skew is in plus 2 orus +2 and let's say that it's two by + + align:start position:0% +2 and let's say that it's two by + + + align:start position:0% +2 and let's say that it's two by +symmetry so um my picture + + align:start position:0% +symmetry so um my picture + + + align:start position:0% +symmetry so um my picture +is I'm going to draw double right + + align:start position:0% +is I'm going to draw double right + + + align:start position:0% +is I'm going to draw double right +arrow to say + + align:start position:0% + + + + align:start position:0% + +that this sub tree is two higher than + + align:start position:0% +that this sub tree is two higher than + + + align:start position:0% +that this sub tree is two higher than +this sub tree okay so that's bad and we + + align:start position:0% +this sub tree okay so that's bad and we + + + align:start position:0% +this sub tree okay so that's bad and we +want to fix it the obvious thing to do + + align:start position:0% +want to fix it the obvious thing to do + + + align:start position:0% +want to fix it the obvious thing to do +is to rotate this Edge because that'll + + align:start position:0% +is to rotate this Edge because that'll + + + align:start position:0% +is to rotate this Edge because that'll +make this this is + + align:start position:0% +make this this is + + + align:start position:0% +make this this is +too this is too high and this is too low + + align:start position:0% +too this is too high and this is too low + + + align:start position:0% +too this is too high and this is too low +so if we rotate this should go down by + + align:start position:0% +so if we rotate this should go down by + + + align:start position:0% +so if we rotate this should go down by +one and this should go up by one and + + align:start position:0% +one and this should go up by one and + + + align:start position:0% +one and this should go up by one and +that works most of the + + align:start position:0% +that works most of the + + + align:start position:0% +that works most of the +time so case + + align:start position:0% +time so case + + + align:start position:0% +time so case +one is that + + align:start position:0% +one is that + + + align:start position:0% +one is that +skew of Y what is y I want y to be the + + align:start position:0% +skew of Y what is y I want y to be the + + + align:start position:0% +skew of Y what is y I want y to be the +right child of X because we have + + align:start position:0% +right child of X because we have + + + align:start position:0% +right child of X because we have +positive skew we know there is a right + + align:start position:0% +positive skew we know there is a right + + + align:start position:0% +positive skew we know there is a right +child now uh because this was the lowest + + align:start position:0% +child now uh because this was the lowest + + + align:start position:0% +child now uh because this was the lowest +bad we know that Y is actually good it's + + align:start position:0% +bad we know that Y is actually good it's + + + align:start position:0% +bad we know that Y is actually good it's +either right heavy or even the two sub + + align:start position:0% +either right heavy or even the two sub + + + align:start position:0% +either right heavy or even the two sub +trees have the same height or left heavy + + align:start position:0% +trees have the same height or left heavy + + + align:start position:0% +trees have the same height or left heavy +the easy + + align:start position:0% +the easy + + + align:start position:0% +the easy +cases uh + + align:start position:0% + + + + align:start position:0% + +are when skew of Y is either one or + + align:start position:0% + + + + align:start position:0% + +zero which I will draw + + align:start position:0% + + + + align:start position:0% + +all right so double right arrow let's + + align:start position:0% +all right so double right arrow let's + + + align:start position:0% +all right so double right arrow let's +say single right + + align:start position:0% + + + + align:start position:0% + +arrow so this uh I'm just going to add + + align:start position:0% +arrow so this uh I'm just going to add + + + align:start position:0% +arrow so this uh I'm just going to add +some labels here to make this picture + + align:start position:0% + + + + align:start position:0% + +consistent uh k + one K plus two I'm + + align:start position:0% +consistent uh k + one K plus two I'm + + + align:start position:0% +consistent uh k + one K plus two I'm +writing the heights so this is an + + align:start position:0% +writing the heights so this is an + + + align:start position:0% +writing the heights so this is an +example where C is is taller than b + + align:start position:0% +example where C is is taller than b + + + align:start position:0% +example where C is is taller than b +uh B A and B are the same height and + + align:start position:0% +uh B A and B are the same height and + + + align:start position:0% +uh B A and B are the same height and +then if you compute the heights up here + + align:start position:0% +then if you compute the heights up here + + + align:start position:0% +then if you compute the heights up here +indeed uh this one is right leaning this + + align:start position:0% +indeed uh this one is right leaning this + + + align:start position:0% +indeed uh this one is right leaning this +one is doubly right leaning this one has + + align:start position:0% +one is doubly right leaning this one has + + + align:start position:0% +one is doubly right leaning this one has +height K plus one this one has height K + + align:start position:0% +height K plus one this one has height K + + + align:start position:0% +height K plus one this one has height K +minus one that's bad but if we do this + + align:start position:0% +minus one that's bad but if we do this + + + align:start position:0% +minus one that's bad but if we do this +right rotation on X we get exactly what + + align:start position:0% +right rotation on X we get exactly what + + + align:start position:0% +right rotation on X we get exactly what +we + + align:start position:0% + + + + align:start position:0% + +want so I'm just going to copy the + + align:start position:0% +want so I'm just going to copy the + + + align:start position:0% +want so I'm just going to copy the +labels on ABC we have k minus1 k minus + + align:start position:0% +labels on ABC we have k minus1 k minus + + + align:start position:0% +labels on ABC we have k minus1 k minus +one and K and then recompute that means + + align:start position:0% +one and K and then recompute that means + + + align:start position:0% +one and K and then recompute that means +this guy has height K this one has + + align:start position:0% +this guy has height K this one has + + + align:start position:0% +this guy has height K this one has +height k + 1 and now all the nodes in + + align:start position:0% +height k + 1 and now all the nodes in + + + align:start position:0% +height k + 1 and now all the nodes in +this picture that I've highlighted A and + + align:start position:0% +this picture that I've highlighted A and + + + align:start position:0% +this picture that I've highlighted A and +C haven't changed they were height + + align:start position:0% +C haven't changed they were height + + + align:start position:0% +C haven't changed they were height +balanced before they still are um but + + align:start position:0% +balanced before they still are um but + + + align:start position:0% +balanced before they still are um but +now X and Y X wasn't height balanced + + align:start position:0% +now X and Y X wasn't height balanced + + + align:start position:0% +now X and Y X wasn't height balanced +before y was now both X and Y are height + + align:start position:0% +before y was now both X and Y are height + + + align:start position:0% +before y was now both X and Y are height +balanced okay that's case one in case + + align:start position:0% +balanced okay that's case one in case + + + align:start position:0% +balanced okay that's case one in case +two the SK of Y is flat which means that + + align:start position:0% +two the SK of Y is flat which means that + + + align:start position:0% +two the SK of Y is flat which means that +this is a k and this is a k and this is + + align:start position:0% +this is a k and this is a k and this is + + + align:start position:0% +this is a k and this is a k and this is +a k + one and this this is a K plus 2 + + align:start position:0% +a k + one and this this is a K plus 2 + + + align:start position:0% +a k + one and this this is a K plus 2 +okay but still all the nodes are + + align:start position:0% +okay but still all the nodes are + + + align:start position:0% +okay but still all the nodes are +balanced height balanced they're still + + align:start position:0% +balanced height balanced they're still + + + align:start position:0% +balanced height balanced they're still +plus or minus one so those are the easy + + align:start position:0% +plus or minus one so those are the easy + + + align:start position:0% +plus or minus one so those are the easy +cases unfortunately there is a hard + + align:start position:0% +cases unfortunately there is a hard + + + align:start position:0% +cases unfortunately there is a hard +case case three but there's only one and + + align:start position:0% +case case three but there's only one and + + + align:start position:0% +case case three but there's only one and +it's not that much + + align:start position:0% + + + + align:start position:0% + +harder so it's when skew of Y is minus + + align:start position:0% +harder so it's when skew of Y is minus + + + align:start position:0% +harder so it's when skew of Y is minus +one in this case we need to look at the + + align:start position:0% +one in this case we need to look at the + + + align:start position:0% +one in this case we need to look at the +left child of Y + + align:start position:0% +left child of Y + + + align:start position:0% +left child of Y +uh okay and to be alphabetical I'm going + + align:start position:0% +uh okay and to be alphabetical I'm going + + + align:start position:0% +uh okay and to be alphabetical I'm going +to rename this to + + align:start position:0% +to rename this to + + + align:start position:0% +to rename this to +Z sorry so this one again is double + + align:start position:0% +Z sorry so this one again is double + + + align:start position:0% +Z sorry so this one again is double +right arrow this one is now left + + align:start position:0% +right arrow this one is now left + + + align:start position:0% +right arrow this one is now left +arrow and this is letter Y and so we + + align:start position:0% +arrow and this is letter Y and so we + + + align:start position:0% +arrow and this is letter Y and so we +have a + + align:start position:0% +have a + + + align:start position:0% +have a +b c and d potential sub trees hanging + + align:start position:0% +b c and d potential sub trees hanging + + + align:start position:0% +b c and d potential sub trees hanging +off of them and I'm going to label the + + align:start position:0% +off of them and I'm going to label the + + + align:start position:0% +off of them and I'm going to label the +heights of these things these are each K + + align:start position:0% +heights of these things these are each K + + + align:start position:0% +heights of these things these are each K +minus one or K minus 2 this one's K + + align:start position:0% +minus one or K minus 2 this one's K + + + align:start position:0% +minus one or K minus 2 this one's K +minus one and now compute the inside so + + align:start position:0% +minus one and now compute the inside so + + + align:start position:0% +minus one and now compute the inside so +this is going to be height k for this to + + align:start position:0% +this is going to be height k for this to + + + align:start position:0% +this is going to be height k for this to +be uh left leaning so this is k + 1 and + + align:start position:0% +be uh left leaning so this is k + 1 and + + + align:start position:0% +be uh left leaning so this is k + 1 and +this is k + 2 okay but the problem is + + align:start position:0% +this is k + 2 okay but the problem is + + + align:start position:0% +this is k + 2 okay but the problem is +this is two higher than this the height + + align:start position:0% +this is two higher than this the height + + + align:start position:0% +this is two higher than this the height +of Z is two higher than the height of a + + align:start position:0% +of Z is two higher than the height of a + + + align:start position:0% +of Z is two higher than the height of a +in this case if I do this rotation + + align:start position:0% +in this case if I do this rotation + + + align:start position:0% +in this case if I do this rotation +things get worse actually I'll just tell + + align:start position:0% +things get worse actually I'll just tell + + + align:start position:0% +things get worse actually I'll just tell +you the right thing to + + align:start position:0% +you the right thing to + + + align:start position:0% +you the right thing to +do + + align:start position:0% +do + + + align:start position:0% +do +is this is the one thing you need to + + align:start position:0% + + + + align:start position:0% + +memorize and let me draw the result you + + align:start position:0% +memorize and let me draw the result you + + + align:start position:0% +memorize and let me draw the result you +can also just think of it as redrawing + + align:start position:0% +can also just think of it as redrawing + + + align:start position:0% +can also just think of it as redrawing +the tree like this uh but it's easier + + align:start position:0% +the tree like this uh but it's easier + + + align:start position:0% +the tree like this uh but it's easier +from an analysis perspective to think + + align:start position:0% +from an analysis perspective to think + + + align:start position:0% +from an analysis perspective to think +about it is two rotations so then we can + + align:start position:0% +about it is two rotations so then we can + + + align:start position:0% +about it is two rotations so then we can +just reduce as long as we know rotations + + align:start position:0% +just reduce as long as we know rotations + + + align:start position:0% +just reduce as long as we know rotations +work then we know that this thing works + + align:start position:0% +work then we know that this thing works + + + align:start position:0% +work then we know that this thing works +Works meaning it preserves traversal + + align:start position:0% +Works meaning it preserves traversal + + + align:start position:0% +Works meaning it preserves traversal +order and we can maintain all the + + align:start position:0% +order and we can maintain all the + + + align:start position:0% +order and we can maintain all the +augmentations so now if I copy over + + align:start position:0% +augmentations so now if I copy over + + + align:start position:0% +augmentations so now if I copy over +these labels the height labels I have K + + align:start position:0% +these labels the height labels I have K + + + align:start position:0% +these labels the height labels I have K +minus one I have for these two guys K + + align:start position:0% +minus one I have for these two guys K + + + align:start position:0% +minus one I have for these two guys K +minus one or k minus 2 biggest one is + + align:start position:0% +minus one or k minus 2 biggest one is + + + align:start position:0% +minus one or k minus 2 biggest one is +Kus one this is K minus one and so this + + align:start position:0% +Kus one this is K minus one and so this + + + align:start position:0% +Kus one this is K minus one and so this +will be K this will be K this will be k + + align:start position:0% +will be K this will be K this will be k + + + align:start position:0% +will be K this will be K this will be k ++ one and lo and behold we have a nice + + align:start position:0% ++ one and lo and behold we have a nice + + + align:start position:0% ++ one and lo and behold we have a nice +height balanc Tree in all three cases + + align:start position:0% +height balanc Tree in all three cases + + + align:start position:0% +height balanc Tree in all three cases +for this one node now this was the low + + align:start position:0% +for this one node now this was the low + + + align:start position:0% +for this one node now this was the low +node once we update this one it could be + + align:start position:0% +node once we update this one it could be + + + align:start position:0% +node once we update this one it could be +that um we changed the height of the + + align:start position:0% +that um we changed the height of the + + + align:start position:0% +that um we changed the height of the +root before it was k + 2 now it's k+ one + + align:start position:0% +root before it was k + 2 now it's k+ one + + + align:start position:0% +root before it was k + 2 now it's k+ one +or sometimes we keep it the same like + + align:start position:0% +or sometimes we keep it the same like + + + align:start position:0% +or sometimes we keep it the same like +over in this case uh and so now we have + + align:start position:0% +over in this case uh and so now we have + + + align:start position:0% +over in this case uh and so now we have +to check the parent maybe the parent is + + align:start position:0% +to check the parent maybe the parent is + + + align:start position:0% +to check the parent maybe the parent is +out of balance we just keep walking up + + align:start position:0% +out of balance we just keep walking up + + + align:start position:0% +out of balance we just keep walking up +the node and also maintain all the + + align:start position:0% +the node and also maintain all the + + + align:start position:0% +the node and also maintain all the +augmentations as we go then we'll keep + + align:start position:0% +augmentations as we go then we'll keep + + + align:start position:0% +augmentations as we go then we'll keep +track of height and subtree size if we + + align:start position:0% +track of height and subtree size if we + + + align:start position:0% +track of height and subtree size if we +want them or any other augmentations and + + align:start position:0% +want them or any other augmentations and + + + align:start position:0% +want them or any other augmentations and +after order H operations we will have + + align:start position:0% +after order H operations we will have + + + align:start position:0% +after order H operations we will have +restored the height balance property + + align:start position:0% +restored the height balance property + + + align:start position:0% +restored the height balance property +which means all the way through H equals + + align:start position:0% +which means all the way through H equals + + + align:start position:0% +which means all the way through H equals +order log n and so all of our operations + + align:start position:0% +order log n and so all of our operations + + + align:start position:0% +order log n and so all of our operations +now are magically order log n \ No newline at end of file diff --git a/UP--RL-YKhE.txt b/UP--RL-YKhE.txt new file mode 100644 index 0000000000000000000000000000000000000000..856510c2a2a94223f75d125ed0128c7f2fca6bbf --- /dev/null +++ b/UP--RL-YKhE.txt @@ -0,0 +1,10363 @@ +align:start position:0% + +So + + align:start position:0% +So + + + align:start position:0% +So +next we will so we we're switching away + + align:start position:0% +next we will so we we're switching away + + + align:start position:0% +next we will so we we're switching away +from metric basis and we talk about + + align:start position:0% +from metric basis and we talk about + + + align:start position:0% +from metric basis and we talk about +differentiation. + + align:start position:0% +differentiation. + + + align:start position:0% +differentiation. +So if we have a function + + align:start position:0% +So if we have a function + + + align:start position:0% +So if we have a function +uh on R say + + align:start position:0% + + + + align:start position:0% + +uh and then we say that + + align:start position:0% + + + + align:start position:0% + +that uh that x that f is differentiable. + + align:start position:0% + + + + align:start position:0% + +at x0. If the limit here + + align:start position:0% + + + + align:start position:0% + +if the limit uh f ofx minus f of x0 if + + align:start position:0% +if the limit uh f ofx minus f of x0 if + + + align:start position:0% +if the limit uh f ofx minus f of x0 if +the divided by x - x0 if this limit here + + align:start position:0% +the divided by x - x0 if this limit here + + + align:start position:0% +the divided by x - x0 if this limit here +exist + + align:start position:0% + + + + align:start position:0% + +um if this limit here exists + + align:start position:0% +um if this limit here exists + + + align:start position:0% +um if this limit here exists +as x go to x0 + + align:start position:0% + + + + align:start position:0% + +this here This here this quotient here + + align:start position:0% +this here This here this quotient here + + + align:start position:0% +this here This here this quotient here +is usually called the difference quotion + + align:start position:0% + + + + align:start position:0% + +and it's always of course when you form + + align:start position:0% +and it's always of course when you form + + + align:start position:0% +and it's always of course when you form +this different quotient it's always + + align:start position:0% +this different quotient it's always + + + align:start position:0% +this different quotient it's always +assumed obviously that x is not equal to + + align:start position:0% +assumed obviously that x is not equal to + + + align:start position:0% +assumed obviously that x is not equal to +x0 so that the denominator makes sense + + align:start position:0% +x0 so that the denominator makes sense + + + align:start position:0% +x0 so that the denominator makes sense +right so if this limit here as x go to + + align:start position:0% +right so if this limit here as x go to + + + align:start position:0% +right so if this limit here as x go to +x0 if this exists then we say that the + + align:start position:0% +x0 if this exists then we say that the + + + align:start position:0% +x0 if this exists then we say that the +function f is differentiable at x0 and + + align:start position:0% +function f is differentiable at x0 and + + + align:start position:0% +function f is differentiable at x0 and +the limit is called the derivative of f + + align:start position:0% +the limit is called the derivative of f + + + align:start position:0% +the limit is called the derivative of f +at x0 and this is how it's denoted. + + align:start position:0% +at x0 and this is how it's denoted. + + + align:start position:0% +at x0 and this is how it's denoted. +Okay. + + align:start position:0% + + + + align:start position:0% + +So now + + align:start position:0% +So now + + + align:start position:0% +So now +the simplest possible example of this + + align:start position:0% +the simplest possible example of this + + + align:start position:0% +the simplest possible example of this +would be + + align:start position:0% +would be + + + align:start position:0% +would be +uh that suppose that you're looking at a + + align:start position:0% +uh that suppose that you're looking at a + + + align:start position:0% +uh that suppose that you're looking at a +function that is constant. of f is equal + + align:start position:0% +function that is constant. of f is equal + + + align:start position:0% +function that is constant. of f is equal +to f for some constant + + align:start position:0% + + + + align:start position:0% + +uh c + + align:start position:0% + + + + align:start position:0% + +uh then if you're looking at this + + align:start position:0% +uh then if you're looking at this + + + align:start position:0% +uh then if you're looking at this +difference quotient so f of x - f of x0 + + align:start position:0% +difference quotient so f of x - f of x0 + + + align:start position:0% +difference quotient so f of x - f of x0 +x - x0 + + align:start position:0% +x - x0 + + + align:start position:0% +x - x0 +well the value at any point is c so this + + align:start position:0% +well the value at any point is c so this + + + align:start position:0% +well the value at any point is c so this +here is c minus c / X - Y X 0 and so the + + align:start position:0% +here is c minus c / X - Y X 0 and so the + + + align:start position:0% +here is c minus c / X - Y X 0 and so the +denominator is zero. So this whole thing + + align:start position:0% +denominator is zero. So this whole thing + + + align:start position:0% +denominator is zero. So this whole thing +is zero and so of course the limit this + + align:start position:0% +is zero and so of course the limit this + + + align:start position:0% +is zero and so of course the limit this +is zero for each X + + align:start position:0% +is zero for each X + + + align:start position:0% +is zero for each X +and also it takes zero. So in particular + + align:start position:0% +and also it takes zero. So in particular + + + align:start position:0% +and also it takes zero. So in particular +of course the limit here exist. So the + + align:start position:0% +of course the limit here exist. So the + + + align:start position:0% +of course the limit here exist. So the +limit here of the different quotient + + align:start position:0% +limit here of the different quotient + + + align:start position:0% +limit here of the different quotient +uh exist + + align:start position:0% + + + + align:start position:0% + +and it's equal to zero right because + + align:start position:0% +and it's equal to zero right because + + + align:start position:0% +and it's equal to zero right because +it's zero for all x for a given x0. + + align:start position:0% +it's zero for all x for a given x0. + + + align:start position:0% +it's zero for all x for a given x0. +So that would be like the simplest + + align:start position:0% +So that would be like the simplest + + + align:start position:0% +So that would be like the simplest +possible example. The second simplest + + align:start position:0% +possible example. The second simplest + + + align:start position:0% +possible example. The second simplest +example, second most simple example + + align:start position:0% +example, second most simple example + + + align:start position:0% +example, second most simple example +would be that you're looking at a linear + + align:start position:0% +would be that you're looking at a linear + + + align:start position:0% +would be that you're looking at a linear +function. So let's say that f ofx is + + align:start position:0% +function. So let's say that f ofx is + + + align:start position:0% +function. So let's say that f ofx is +equal to x, right? In this case, the + + align:start position:0% +equal to x, right? In this case, the + + + align:start position:0% +equal to x, right? In this case, the +difference quotient. + + align:start position:0% +difference quotient. + + + align:start position:0% +difference quotient. +So the difference quotient here, + + align:start position:0% + + + + align:start position:0% + +well this here is x. + + align:start position:0% +well this here is x. + + + align:start position:0% +well this here is x. +This here is x0. + + align:start position:0% + + + + align:start position:0% + +So this here is for each x and x0. This + + align:start position:0% +So this here is for each x and x0. This + + + align:start position:0% +So this here is for each x and x0. This +is one. So the limit of course in this + + align:start position:0% +is one. So the limit of course in this + + + align:start position:0% +is one. So the limit of course in this +case also exist. + + align:start position:0% + + + + align:start position:0% + +The limit here exist and it's equal to + + align:start position:0% +The limit here exist and it's equal to + + + align:start position:0% +The limit here exist and it's equal to +to one. + + align:start position:0% + + + + align:start position:0% + +Right? So in this case, so in this case + + align:start position:0% +Right? So in this case, so in this case + + + align:start position:0% +Right? So in this case, so in this case +f is differentiable + + align:start position:0% + + + + align:start position:0% + +at all points and the derivative at all + + align:start position:0% +at all points and the derivative at all + + + align:start position:0% +at all points and the derivative at all +points is equal to zero. In this case, f + + align:start position:0% +points is equal to zero. In this case, f + + + align:start position:0% +points is equal to zero. In this case, f +here is also differentiable + + align:start position:0% + + + + align:start position:0% + +and the derivative at all points is + + align:start position:0% +and the derivative at all points is + + + align:start position:0% +and the derivative at all points is +equal to one. + + align:start position:0% + + + + align:start position:0% + +Okay. So now in general how do we + + align:start position:0% +Okay. So now in general how do we + + + align:start position:0% +Okay. So now in general how do we +compute the so how do we compute the + + align:start position:0% +compute the so how do we compute the + + + align:start position:0% +compute the so how do we compute the +derivative of a function? + + align:start position:0% + + + + align:start position:0% + +Uh how how do we + + align:start position:0% + + + + align:start position:0% + +compute the derivative + + align:start position:0% + + + + align:start position:0% + +and for that there are some some basic + + align:start position:0% +and for that there are some some basic + + + align:start position:0% +and for that there are some some basic +uh laws how to compute it. So there's + + align:start position:0% +uh laws how to compute it. So there's + + + align:start position:0% +uh laws how to compute it. So there's +these laws + + align:start position:0% + + + + align:start position:0% + +um the sum rule + + align:start position:0% + + + + align:start position:0% + +uh what's usually called the liess rule. + + align:start position:0% + + + + align:start position:0% + +uh the quotient rule + + align:start position:0% + + + + align:start position:0% + +and then uh also the chain rule. + + align:start position:0% + + + + align:start position:0% + +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +Now let me uh look at the first three + + align:start position:0% +Now let me uh look at the first three + + + align:start position:0% +Now let me uh look at the first three +rules first. + + align:start position:0% +rules first. + + + align:start position:0% +rules first. +So um + + align:start position:0% +So um + + + align:start position:0% +So um +I have uh two functions f and g they are + + align:start position:0% +I have uh two functions f and g they are + + + align:start position:0% +I have uh two functions f and g they are +defined say on r but it could have been + + align:start position:0% +defined say on r but it could have been + + + align:start position:0% +defined say on r but it could have been +a subset of r + + align:start position:0% +a subset of r + + + align:start position:0% +a subset of r +uh and uh I'm assuming that that they + + align:start position:0% +uh and uh I'm assuming that that they + + + align:start position:0% +uh and uh I'm assuming that that they +are both + + align:start position:0% +are both + + + align:start position:0% +are both +and both + + align:start position:0% +and both + + + align:start position:0% +and both +right actually I need we'll need one + + align:start position:0% +right actually I need we'll need one + + + align:start position:0% +right actually I need we'll need one +okay so both Um + + align:start position:0% +okay so both Um + + + align:start position:0% +okay so both Um +f and g are differentiable + + align:start position:0% + + + + align:start position:0% + +at x0. + + align:start position:0% +at x0. + + + align:start position:0% +at x0. +Then we have the following. So we have + + align:start position:0% +Then we have the following. So we have + + + align:start position:0% +Then we have the following. So we have +the following lema. + + align:start position:0% + + + + align:start position:0% + +Uh + + align:start position:0% + + + + align:start position:0% + +uh one is we have that. So one and this + + align:start position:0% +uh one is we have that. So one and this + + + align:start position:0% +uh one is we have that. So one and this +is really the sum rule. + + align:start position:0% + + + + align:start position:0% + +We have that the sum here f plus g. So + + align:start position:0% +We have that the sum here f plus g. So + + + align:start position:0% +We have that the sum here f plus g. So +the sum of these two functions this is + + align:start position:0% +the sum of these two functions this is + + + align:start position:0% +the sum of these two functions this is +the function that is just in x is just a + + align:start position:0% +the function that is just in x is just a + + + align:start position:0% +the function that is just in x is just a +sum of f ofx and g of x. We have that + + align:start position:0% +sum of f ofx and g of x. We have that + + + align:start position:0% +sum of f ofx and g of x. We have that +this function here + + align:start position:0% +this function here + + + align:start position:0% +this function here +f + g is differentiable + + align:start position:0% + + + + align:start position:0% + +at x0 + + align:start position:0% +at x0 + + + align:start position:0% +at x0 +and the derivative f + g. The derivative + + align:start position:0% +and the derivative f + g. The derivative + + + align:start position:0% +and the derivative f + g. The derivative +of this nx0 is just a sum of the + + align:start position:0% +of this nx0 is just a sum of the + + + align:start position:0% +of this nx0 is just a sum of the +derivative. + + align:start position:0% + + + + align:start position:0% + +Okay, + + align:start position:0% + + + + align:start position:0% + +let me let me prove this one here right + + align:start position:0% +let me let me prove this one here right + + + align:start position:0% +let me let me prove this one here right +away. So let me + + align:start position:0% + + + + align:start position:0% + +so let's prove this. + + align:start position:0% + + + + align:start position:0% + +So we have the sum. So uh we we will we + + align:start position:0% +So we have the sum. So uh we we will we + + + align:start position:0% +So we have the sum. So uh we we will we +are going to look at so we form the + + align:start position:0% +are going to look at so we form the + + + align:start position:0% +are going to look at so we form the +difference. So form the difference + + align:start position:0% +difference. So form the difference + + + align:start position:0% +difference. So form the difference +quotion. + + align:start position:0% + + + + align:start position:0% + +So f + g + + align:start position:0% +So f + g + + + align:start position:0% +So f + g +at x - f + g + + align:start position:0% +at x - f + g + + + align:start position:0% +at x - f + g +at x0 + + align:start position:0% +at x0 + + + align:start position:0% +at x0 +x - x0 + + align:start position:0% +x - x0 + + + align:start position:0% +x - x0 +right so now what is this? So this here + + align:start position:0% +right so now what is this? So this here + + + align:start position:0% +right so now what is this? So this here +is + + align:start position:0% +is + + + align:start position:0% +is +uh this is just f of x plus g of x + + align:start position:0% +uh this is just f of x plus g of x + + + align:start position:0% +uh this is just f of x plus g of x +minus and then f of x0 plus g of x0 + + align:start position:0% +minus and then f of x0 plus g of x0 + + + align:start position:0% +minus and then f of x0 plus g of x0 +and then divided by x - x0 right + + align:start position:0% +and then divided by x - x0 right + + + align:start position:0% +and then divided by x - x0 right +and so then you can split this up into + + align:start position:0% +and so then you can split this up into + + + align:start position:0% +and so then you can split this up into +two. You can write this difference + + align:start position:0% +two. You can write this difference + + + align:start position:0% +two. You can write this difference +quotion as if you split it up. If you + + align:start position:0% +quotion as if you split it up. If you + + + align:start position:0% +quotion as if you split it up. If you +collect the fs in a nominator. + + align:start position:0% +collect the fs in a nominator. + + + align:start position:0% +collect the fs in a nominator. +So I just collect the fs + + align:start position:0% + + + + align:start position:0% + +and then afterwards I collect the and I + + align:start position:0% +and then afterwards I collect the and I + + + align:start position:0% +and then afterwards I collect the and I +put it on two different fractions. + + align:start position:0% +put it on two different fractions. + + + align:start position:0% +put it on two different fractions. +Separate them out and then I collect the + + align:start position:0% +Separate them out and then I collect the + + + align:start position:0% +Separate them out and then I collect the +G's. + + align:start position:0% + + + + align:start position:0% + +And now you see that because f was + + align:start position:0% +And now you see that because f was + + + align:start position:0% +And now you see that because f was +differentiable at x0 this thing here as + + align:start position:0% +differentiable at x0 this thing here as + + + align:start position:0% +differentiable at x0 this thing here as +x go to x0 this here goes to fprime. So + + align:start position:0% +x go to x0 this here goes to fprime. So + + + align:start position:0% +x go to x0 this here goes to fprime. So +this here goes to f prime of x0. This is + + align:start position:0% +this here goes to f prime of x0. This is + + + align:start position:0% +this here goes to f prime of x0. This is +what this difference quotient here. And + + align:start position:0% +what this difference quotient here. And + + + align:start position:0% +what this difference quotient here. And +this difference quotient goes to g prime + + align:start position:0% +this difference quotient goes to g prime + + + align:start position:0% +this difference quotient goes to g prime +of zero. So you have that indeed it does + + align:start position:0% +of zero. So you have that indeed it does + + + align:start position:0% +of zero. So you have that indeed it does +converge and this is what it converts to + + align:start position:0% +converge and this is what it converts to + + + align:start position:0% +converge and this is what it converts to +right and so this prove that the sum of + + align:start position:0% +right and so this prove that the sum of + + + align:start position:0% +right and so this prove that the sum of +these two functions is also + + align:start position:0% +these two functions is also + + + align:start position:0% +these two functions is also +differentiable and their derivative is + + align:start position:0% +differentiable and their derivative is + + + align:start position:0% +differentiable and their derivative is +the sum of the derivative okay the next + + align:start position:0% +the sum of the derivative okay the next + + + align:start position:0% +the sum of the derivative okay the next +thing we will prove is len rule but + + align:start position:0% +thing we will prove is len rule but + + + align:start position:0% +thing we will prove is len rule but +before that I need to kind of step back + + align:start position:0% +before that I need to kind of step back + + + align:start position:0% +before that I need to kind of step back +and I want to so before proving so the + + align:start position:0% +and I want to so before proving so the + + + align:start position:0% +and I want to so before proving so the +next uh maybe I'll just state it and + + align:start position:0% +next uh maybe I'll just state it and + + + align:start position:0% +next uh maybe I'll just state it and +then we'll go back and we need something + + align:start position:0% +then we'll go back and we need something + + + align:start position:0% +then we'll go back and we need something +The next is what's called liveness rule. + + align:start position:0% + + + + align:start position:0% + +So it's all you know you could also call + + align:start position:0% +So it's all you know you could also call + + + align:start position:0% +So it's all you know you could also call +it product rule but it's really quite + + align:start position:0% +it product rule but it's really quite + + + align:start position:0% +it product rule but it's really quite +generally called the lieness rule. + + align:start position:0% +generally called the lieness rule. + + + align:start position:0% +generally called the lieness rule. +And so this is when you looking at the + + align:start position:0% +And so this is when you looking at the + + + align:start position:0% +And so this is when you looking at the +product of these function. So the + + align:start position:0% +product of these function. So the + + + align:start position:0% +product of these function. So the +product function, + + align:start position:0% +product function, + + + align:start position:0% +product function, +the product function is a function in x + + align:start position:0% +the product function is a function in x + + + align:start position:0% +the product function is a function in x +that is just the product of f ofx and g + + align:start position:0% +that is just the product of f ofx and g + + + align:start position:0% +that is just the product of f ofx and g +of x + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +and lightness rule. + + align:start position:0% +and lightness rule. + + + align:start position:0% +and lightness rule. +Lightness rule it say the following + + align:start position:0% + + + + align:start position:0% + +that if f and g are differentiable at x0 + + align:start position:0% +that if f and g are differentiable at x0 + + + align:start position:0% +that if f and g are differentiable at x0 +then the product of these two function + + align:start position:0% +then the product of these two function + + + align:start position:0% +then the product of these two function +here + + align:start position:0% +here + + + align:start position:0% +here +is also differentiable at x0. + + align:start position:0% +is also differentiable at x0. + + + align:start position:0% +is also differentiable at x0. +And the derivative of the product is the + + align:start position:0% +And the derivative of the product is the + + + align:start position:0% +And the derivative of the product is the +derivative of the first function at x0 + + align:start position:0% +derivative of the first function at x0 + + + align:start position:0% +derivative of the first function at x0 +times the value of the second function + + align:start position:0% +times the value of the second function + + + align:start position:0% +times the value of the second function +at x0 plus the uh the symmetric in f and + + align:start position:0% +at x0 plus the uh the symmetric in f and + + + align:start position:0% +at x0 plus the uh the symmetric in f and +g which is the value of f at x0 times + + align:start position:0% +g which is the value of f at x0 times + + + align:start position:0% +g which is the value of f at x0 times +the derivative of g at x0. Right? So the + + align:start position:0% +the derivative of g at x0. Right? So the + + + align:start position:0% +the derivative of g at x0. Right? So the +product is differentiable at x0 also. + + align:start position:0% +product is differentiable at x0 also. + + + align:start position:0% +product is differentiable at x0 also. +And this is what the derivative is. And + + align:start position:0% +And this is what the derivative is. And + + + align:start position:0% +And this is what the derivative is. And +in the notes, I just copied a little bit + + align:start position:0% +in the notes, I just copied a little bit + + + align:start position:0% +in the notes, I just copied a little bit +of thing just for fun from Wikipedia + + align:start position:0% +of thing just for fun from Wikipedia + + + align:start position:0% +of thing just for fun from Wikipedia +about lightnings. That was kind of + + align:start position:0% +about lightnings. That was kind of + + + align:start position:0% +about lightnings. That was kind of +interesting figure and played an + + align:start position:0% +interesting figure and played an + + + align:start position:0% +interesting figure and played an +important role long time ago. + + align:start position:0% +important role long time ago. + + + align:start position:0% +important role long time ago. +Okay. So before I want to prove this, + + align:start position:0% +Okay. So before I want to prove this, + + + align:start position:0% +Okay. So before I want to prove this, +let me step back and let me make an + + align:start position:0% +let me step back and let me make an + + + align:start position:0% +let me step back and let me make an +observation about + + align:start position:0% +observation about + + + align:start position:0% +observation about +um + + align:start position:0% +um + + + align:start position:0% +um +uh what it means to be differentiable at + + align:start position:0% +uh what it means to be differentiable at + + + align:start position:0% +uh what it means to be differentiable at +a point. + + align:start position:0% + + + + align:start position:0% + +So So this is the next lemon. + + align:start position:0% + + + + align:start position:0% + +So you have a function f + + align:start position:0% +So you have a function f + + + align:start position:0% +So you have a function f +on r into r + + align:start position:0% + + + + align:start position:0% + +and and you assume that um uh f so if + + align:start position:0% +and and you assume that um uh f so if + + + align:start position:0% +and and you assume that um uh f so if +f here is differentiable + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +at x0. Then I claim that then f here is + + align:start position:0% +at x0. Then I claim that then f here is + + + align:start position:0% +at x0. Then I claim that then f here is +also continuous + + align:start position:0% + + + + align:start position:0% + +at x0. Okay. Okay. So, so in other + + align:start position:0% +at x0. Okay. Okay. So, so in other + + + align:start position:0% +at x0. Okay. Okay. So, so in other +words, different being differentiable is + + align:start position:0% +words, different being differentiable is + + + align:start position:0% +words, different being differentiable is +stronger than being continuous. + + align:start position:0% +stronger than being continuous. + + + align:start position:0% +stronger than being continuous. +In a minute, we will see an example of + + align:start position:0% +In a minute, we will see an example of + + + align:start position:0% +In a minute, we will see an example of +something that's continuous but not + + align:start position:0% +something that's continuous but not + + + align:start position:0% +something that's continuous but not +differentiable. + + align:start position:0% +differentiable. + + + align:start position:0% +differentiable. +And so + + align:start position:0% +And so + + + align:start position:0% +And so +uh okay so now let's try to prove that + + align:start position:0% + + + + align:start position:0% + +so right so I'm assuming that it's + + align:start position:0% +so right so I'm assuming that it's + + + align:start position:0% +so right so I'm assuming that it's +differentiable so this means that + + align:start position:0% +differentiable so this means that + + + align:start position:0% +differentiable so this means that +this + + align:start position:0% +this + + + align:start position:0% +this +this difference quotient here + + align:start position:0% + + + + align:start position:0% + +this here has a limit and that limit is + + align:start position:0% +this here has a limit and that limit is + + + align:start position:0% +this here has a limit and that limit is +the derivative right as x go to x0. + + align:start position:0% +the derivative right as x go to x0. + + + align:start position:0% +the derivative right as x go to x0. +So this means that um that there exist + + align:start position:0% + + + + align:start position:0% + +uh there exist delta greater than zero + + align:start position:0% +uh there exist delta greater than zero + + + align:start position:0% +uh there exist delta greater than zero +such that + + align:start position:0% +such that + + + align:start position:0% +such that +if x here + + align:start position:0% +if x here + + + align:start position:0% +if x here +uh minus x0 + + align:start position:0% +uh minus x0 + + + align:start position:0% +uh minus x0 +is less than delta + + align:start position:0% +is less than delta + + + align:start position:0% +is less than delta +right of course I'm assuming that it's + + align:start position:0% +right of course I'm assuming that it's + + + align:start position:0% +right of course I'm assuming that it's +not equal to x0. + + align:start position:0% +not equal to x0. + + + align:start position:0% +not equal to x0. +If it is less than the difference to uh + + align:start position:0% +If it is less than the difference to uh + + + align:start position:0% +If it is less than the difference to uh +between x and x0 is less than delta, + + align:start position:0% +between x and x0 is less than delta, + + + align:start position:0% +between x and x0 is less than delta, +then this difference quotient here then + + align:start position:0% +then this difference quotient here then + + + align:start position:0% +then this difference quotient here then +f of x - f + + align:start position:0% +f of x - f + + + align:start position:0% +f of x - f +of x0 + + align:start position:0% +of x0 + + + align:start position:0% +of x0 +x - x0 + + align:start position:0% +x - x0 + + + align:start position:0% +x - x0 +- frime of x0. this thing here have to + + align:start position:0% +- frime of x0. this thing here have to + + + align:start position:0% +- frime of x0. this thing here have to +be less than one right I mean this is + + align:start position:0% +be less than one right I mean this is + + + align:start position:0% +be less than one right I mean this is +just using that this limit exists and + + align:start position:0% +just using that this limit exists and + + + align:start position:0% +just using that this limit exists and +I'm sort of using in place of epsilon + + align:start position:0% +I'm sort of using in place of epsilon + + + align:start position:0% +I'm sort of using in place of epsilon +I'm using one right + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +now so this means just multiplying over + + align:start position:0% +now so this means just multiplying over + + + align:start position:0% +now so this means just multiplying over +and And multiplying over you get that f + + align:start position:0% +and And multiplying over you get that f + + + align:start position:0% +and And multiplying over you get that f +ofx + + align:start position:0% +ofx + + + align:start position:0% +ofx +minus f of x0 + + align:start position:0% + + + + align:start position:0% + +uh minus + + align:start position:0% +uh minus + + + align:start position:0% +uh minus +frime + + align:start position:0% + + + + align:start position:0% + +uh of x0 + + align:start position:0% +uh of x0 + + + align:start position:0% +uh of x0 +this thing here + + align:start position:0% +this thing here + + + align:start position:0% +this thing here +uh times I'm I'm multiplying both sides. + + align:start position:0% +uh times I'm I'm multiplying both sides. + + + align:start position:0% +uh times I'm I'm multiplying both sides. +So I'm multiplying + + align:start position:0% + + + + align:start position:0% + +both sides + + align:start position:0% + + + + align:start position:0% + +uh by + + align:start position:0% +uh by + + + align:start position:0% +uh by +uh x - x0. This is a positive thing, + + align:start position:0% +uh x - x0. This is a positive thing, + + + align:start position:0% +uh x - x0. This is a positive thing, +right? So I'm multiplying both sync by + + align:start position:0% +right? So I'm multiplying both sync by + + + align:start position:0% +right? So I'm multiplying both sync by +that. So then I get this thing here x - + + align:start position:0% +that. So then I get this thing here x - + + + align:start position:0% +that. So then I get this thing here x - +x0. + + align:start position:0% +x0. + + + align:start position:0% +x0. +Uh and then I get less less strictly + + align:start position:0% +Uh and then I get less less strictly + + + align:start position:0% +Uh and then I get less less strictly +less than x - x0, right? Because this + + align:start position:0% +less than x - x0, right? Because this + + + align:start position:0% +less than x - x0, right? Because this +here is strictly positive. + + align:start position:0% +here is strictly positive. + + + align:start position:0% +here is strictly positive. +because x is not equal to x0. So I have + + align:start position:0% +because x is not equal to x0. So I have + + + align:start position:0% +because x is not equal to x0. So I have +that and so I get that. So I now I just + + align:start position:0% +that and so I get that. So I now I just + + + align:start position:0% +that and so I get that. So I now I just +split it up. So I have that f ofx - f of + + align:start position:0% +split it up. So I have that f ofx - f of + + + align:start position:0% +split it up. So I have that f ofx - f of +x0 + + align:start position:0% + + + + align:start position:0% + +is now less than + + align:start position:0% +is now less than + + + align:start position:0% +is now less than +x - x0 + + align:start position:0% +x - x0 + + + align:start position:0% +x - x0 +plus frime of x0. + + align:start position:0% + + + + align:start position:0% + +time uh x - x0 + + align:start position:0% + + + + align:start position:0% + +right this is just the triangle + + align:start position:0% +right this is just the triangle + + + align:start position:0% +right this is just the triangle +inequality that we've used many times + + align:start position:0% +inequality that we've used many times + + + align:start position:0% +inequality that we've used many times +just on + + align:start position:0% + + + + align:start position:0% + +right + + align:start position:0% +right + + + align:start position:0% +right +and so now you see that um that if you + + align:start position:0% +and so now you see that um that if you + + + align:start position:0% +and so now you see that um that if you +now + + align:start position:0% +now + + + align:start position:0% +now +um so given + + align:start position:0% +um so given + + + align:start position:0% +um so given +so now if you so now and this here of + + align:start position:0% +so now if you so now and this here of + + + align:start position:0% +so now if you so now and this here of +course I can also write + + align:start position:0% +course I can also write + + + align:start position:0% +course I can also write +uh like this + + align:start position:0% +uh like this + + + align:start position:0% +uh like this +sorry I can just factor this out and I + + align:start position:0% +sorry I can just factor this out and I + + + align:start position:0% +sorry I can just factor this out and I +can write it as 1 + frime of x0 + + align:start position:0% +can write it as 1 + frime of x0 + + + align:start position:0% +can write it as 1 + frime of x0 +like this fine and so now if I want this + + align:start position:0% +like this fine and so now if I want this + + + align:start position:0% +like this fine and so now if I want this +thing here so so now you can if you were + + align:start position:0% +thing here so so now you can if you were + + + align:start position:0% +thing here so so now you can if you were +to right so now you want to prove that f + + align:start position:0% +to right so now you want to prove that f + + + align:start position:0% +to right so now you want to prove that f +is continuous at x0 so you want this + + align:start position:0% +is continuous at x0 so you want this + + + align:start position:0% +is continuous at x0 so you want this +here to be less than some given epsilon + + align:start position:0% +here to be less than some given epsilon + + + align:start position:0% +here to be less than some given epsilon +So given epsilon + + align:start position:0% +So given epsilon + + + align:start position:0% +So given epsilon +epsilon greater than zero + + align:start position:0% +epsilon greater than zero + + + align:start position:0% +epsilon greater than zero +you uh let + + align:start position:0% +you uh let + + + align:start position:0% +you uh let +delta 1 be like the minimum + + align:start position:0% +delta 1 be like the minimum + + + align:start position:0% +delta 1 be like the minimum +of uh if you let said + + align:start position:0% +of uh if you let said + + + align:start position:0% +of uh if you let said +delta 1 to be the minimum of the delta + + align:start position:0% +delta 1 to be the minimum of the delta + + + align:start position:0% +delta 1 to be the minimum of the delta +that I already chose. So then I have + + align:start position:0% +that I already chose. So then I have + + + align:start position:0% +that I already chose. So then I have +this inequality + + align:start position:0% +this inequality + + + align:start position:0% +this inequality +and then um and then uh epsilon + + align:start position:0% +and then um and then uh epsilon + + + align:start position:0% +and then um and then uh epsilon +uh over 1 + frime of x0 + + align:start position:0% +uh over 1 + frime of x0 + + + align:start position:0% +uh over 1 + frime of x0 +right + + align:start position:0% +right + + + align:start position:0% +right +so if I make delta + + align:start position:0% +so if I make delta + + + align:start position:0% +so if I make delta +I choose delta like this then I have + + align:start position:0% +I choose delta like this then I have + + + align:start position:0% +I choose delta like this then I have +this inequality + + align:start position:0% +this inequality + + + align:start position:0% +this inequality +I fill in that so now I'm assuming that + + align:start position:0% +I fill in that so now I'm assuming that + + + align:start position:0% +I fill in that so now I'm assuming that +this thing here is less than delta 1. + + align:start position:0% +this thing here is less than delta 1. + + + align:start position:0% +this thing here is less than delta 1. +So again I have this inequality because + + align:start position:0% +So again I have this inequality because + + + align:start position:0% +So again I have this inequality because +it's less than delta. So then uh when I + + align:start position:0% +it's less than delta. So then uh when I + + + align:start position:0% +it's less than delta. So then uh when I +fill in here delta 1 + + align:start position:0% +fill in here delta 1 + + + align:start position:0% +fill in here delta 1 +for this then I see that this thing here + + align:start position:0% +for this then I see that this thing here + + + align:start position:0% +for this then I see that this thing here +times this is less than epsilon. + + align:start position:0% +times this is less than epsilon. + + + align:start position:0% +times this is less than epsilon. +This here + + align:start position:0% +This here + + + align:start position:0% +This here +holds + + align:start position:0% + + + + align:start position:0% + +when + + align:start position:0% +when + + + align:start position:0% +when +x - x0 + + align:start position:0% +x - x0 + + + align:start position:0% +x - x0 +is less than delta 1 right again because + + align:start position:0% +is less than delta 1 right again because + + + align:start position:0% +is less than delta 1 right again because +if it's less than delta 1 it's less than + + align:start position:0% +if it's less than delta 1 it's less than + + + align:start position:0% +if it's less than delta 1 it's less than +delta so I have this inequality and then + + align:start position:0% +delta so I have this inequality and then + + + align:start position:0% +delta so I have this inequality and then +I can use that delta 1 since is less + + align:start position:0% +I can use that delta 1 since is less + + + align:start position:0% +I can use that delta 1 since is less +than this + + align:start position:0% +than this + + + align:start position:0% +than this +and then I get this inequality + + align:start position:0% + + + + align:start position:0% + +okay so this prove right so this is + + align:start position:0% +okay so this prove right so this is + + + align:start position:0% +okay so this prove right so this is +really what we want to prove right we + + align:start position:0% +really what we want to prove right we + + + align:start position:0% +really what we want to prove right we +want to prove that if it's + + align:start position:0% +want to prove that if it's + + + align:start position:0% +want to prove that if it's +differentiable then it's also continuous + + align:start position:0% +differentiable then it's also continuous + + + align:start position:0% +differentiable then it's also continuous +and the continuity here I I proved it + + align:start position:0% +and the continuity here I I proved it + + + align:start position:0% +and the continuity here I I proved it +you know with you know epsilon or delta + + align:start position:0% +you know with you know epsilon or delta + + + align:start position:0% +you know with you know epsilon or delta +that you really should prove it like + + align:start position:0% +that you really should prove it like + + + align:start position:0% +that you really should prove it like +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now let's look at some examples so this + + align:start position:0% +now let's look at some examples so this + + + align:start position:0% +now let's look at some examples so this +means that if a function is + + align:start position:0% +means that if a function is + + + align:start position:0% +means that if a function is +differentiable + + align:start position:0% +differentiable + + + align:start position:0% +differentiable +then it's continuous + + align:start position:0% +then it's continuous + + + align:start position:0% +then it's continuous +[Applause] + + align:start position:0% + + + + align:start position:0% + +Let me give you an example + + align:start position:0% +Let me give you an example + + + align:start position:0% +Let me give you an example +uh of a function that is so let me give + + align:start position:0% +uh of a function that is so let me give + + + align:start position:0% +uh of a function that is so let me give +you a few three examples. + + align:start position:0% +you a few three examples. + + + align:start position:0% +you a few three examples. +The first example is maybe the simplest + + align:start position:0% +The first example is maybe the simplest + + + align:start position:0% +The first example is maybe the simplest +one um that so this is the function f + + align:start position:0% +one um that so this is the function f + + + align:start position:0% +one um that so this is the function f +ofx that is equal to the absolute value + + align:start position:0% +ofx that is equal to the absolute value + + + align:start position:0% +ofx that is equal to the absolute value +of of x. So f here is defined on r into + + align:start position:0% +of of x. So f here is defined on r into + + + align:start position:0% +of of x. So f here is defined on r into +r + + align:start position:0% + + + + align:start position:0% + +and it's just the absolute value and so + + align:start position:0% +and it's just the absolute value and so + + + align:start position:0% +and it's just the absolute value and so +I well the absolute value here so we've + + align:start position:0% +I well the absolute value here so we've + + + align:start position:0% +I well the absolute value here so we've +seen before so f here is continuous + + align:start position:0% + + + + align:start position:0% + +it's continuous at all points right uh + + align:start position:0% +it's continuous at all points right uh + + + align:start position:0% +it's continuous at all points right uh +in particular of course at zero right + + align:start position:0% +in particular of course at zero right + + + align:start position:0% +in particular of course at zero right +but if you now form the difference + + align:start position:0% +but if you now form the difference + + + align:start position:0% +but if you now form the difference +quotient, right? Suppose that x here is + + align:start position:0% +quotient, right? Suppose that x here is + + + align:start position:0% +quotient, right? Suppose that x here is +bigger than zero. And now look at the + + align:start position:0% +bigger than zero. And now look at the + + + align:start position:0% +bigger than zero. And now look at the +difference quotient. So the difference + + align:start position:0% +difference quotient. So the difference + + + align:start position:0% +difference quotient. So the difference +quotient uh + + align:start position:0% + + + + align:start position:0% + +uh quotient + + align:start position:0% + + + + align:start position:0% + +at uh at x0 equal to zero. If you're + + align:start position:0% +at uh at x0 equal to zero. If you're + + + align:start position:0% +at uh at x0 equal to zero. If you're +looking at that difference quotient and + + align:start position:0% +looking at that difference quotient and + + + align:start position:0% +looking at that difference quotient and +and you at the you first look at where x + + align:start position:0% +and you at the you first look at where x + + + align:start position:0% +and you at the you first look at where x +is positive if x is positive then uh f + + align:start position:0% +is positive if x is positive then uh f + + + align:start position:0% +is positive if x is positive then uh f +ofx minus f of 0 x - 0 this difference + + align:start position:0% +ofx minus f of 0 x - 0 this difference + + + align:start position:0% +ofx minus f of 0 x - 0 this difference +quotient here if x is positive then this + + align:start position:0% +quotient here if x is positive then this + + + align:start position:0% +quotient here if x is positive then this +thing here is just x. So this is x - 0 + + align:start position:0% +thing here is just x. So this is x - 0 + + + align:start position:0% +thing here is just x. So this is x - 0 +x - 0. So this here is one right this + + align:start position:0% +x - 0. So this here is one right this + + + align:start position:0% +x - 0. So this here is one right this +difference quotient is one. This is when + + align:start position:0% +difference quotient is one. This is when + + + align:start position:0% +difference quotient is one. This is when +x is positive. When x is negative + + align:start position:0% +x is positive. When x is negative + + + align:start position:0% +x is positive. When x is negative +then the then f ofx + + align:start position:0% +then the then f ofx + + + align:start position:0% +then the then f ofx +if x is negative then the absolute value + + align:start position:0% +if x is negative then the absolute value + + + align:start position:0% +if x is negative then the absolute value +is minus x + + align:start position:0% +is minus x + + + align:start position:0% +is minus x +right. So the difference quotient here f + + align:start position:0% +right. So the difference quotient here f + + + align:start position:0% +right. So the difference quotient here f +ofx minus uh f of 0 which is zero x - 0. + + align:start position:0% +ofx minus uh f of 0 which is zero x - 0. + + + align:start position:0% +ofx minus uh f of 0 which is zero x - 0. +This here is just - x + + align:start position:0% +This here is just - x + + + align:start position:0% +This here is just - x +/ x. + + align:start position:0% +/ x. + + + align:start position:0% +/ x. +But this thing here is minus one. + + align:start position:0% +But this thing here is minus one. + + + align:start position:0% +But this thing here is minus one. +So for all if you are if you're looking + + align:start position:0% +So for all if you are if you're looking + + + align:start position:0% +So for all if you are if you're looking +at the difference quotient + + align:start position:0% +at the difference quotient + + + align:start position:0% +at the difference quotient +and you uh that comes from looking at + + align:start position:0% +and you uh that comes from looking at + + + align:start position:0% +and you uh that comes from looking at +the derivative as zero. Then when you + + align:start position:0% +the derivative as zero. Then when you + + + align:start position:0% +the derivative as zero. Then when you +approach zero from the right then the + + align:start position:0% +approach zero from the right then the + + + align:start position:0% +approach zero from the right then the +difference quotient is one. When you + + align:start position:0% +difference quotient is one. When you + + + align:start position:0% +difference quotient is one. When you +approach it from the sorry uh yeah from + + align:start position:0% +approach it from the sorry uh yeah from + + + align:start position:0% +approach it from the sorry uh yeah from +the when you approach it from the left + + align:start position:0% +the when you approach it from the left + + + align:start position:0% +the when you approach it from the left +then the difference quotient is minus + + align:start position:0% +then the difference quotient is minus + + + align:start position:0% +then the difference quotient is minus +one. So it doesn't have a limit right. + + align:start position:0% +one. So it doesn't have a limit right. + + + align:start position:0% +one. So it doesn't have a limit right. +It has a limit from the right from the + + align:start position:0% +It has a limit from the right from the + + + align:start position:0% +It has a limit from the right from the +left but it doesn't have a limit if you + + align:start position:0% +left but it doesn't have a limit if you + + + align:start position:0% +left but it doesn't have a limit if you +don't restrict where it's coming from. + + align:start position:0% +don't restrict where it's coming from. + + + align:start position:0% +don't restrict where it's coming from. +So this function here + + align:start position:0% +So this function here + + + align:start position:0% +So this function here +uh is not differentiable. Yeah. + + align:start position:0% + + + + align:start position:0% + +>> So okay. So this is + + align:start position:0% + + + + align:start position:0% + +right. So + + align:start position:0% +right. So + + + align:start position:0% +right. So +so this so this is so so we did this + + align:start position:0% +so this so this is so so we did this + + + align:start position:0% +so this so this is so so we did this +earlier in the class. So if you take + + align:start position:0% +earlier in the class. So if you take + + + align:start position:0% +earlier in the class. So if you take +so + + align:start position:0% +so + + + align:start position:0% +so +that the difference quotient here + + align:start position:0% + + + + align:start position:0% + +that this thing here is converging to to + + align:start position:0% +that this thing here is converging to to + + + align:start position:0% +that this thing here is converging to to +some number say a right. This here means + + align:start position:0% +some number say a right. This here means + + + align:start position:0% +some number say a right. This here means +that for all for all epsilon greater + + align:start position:0% +that for all for all epsilon greater + + + align:start position:0% +that for all for all epsilon greater +than zero there exist a delta greater + + align:start position:0% +than zero there exist a delta greater + + + align:start position:0% +than zero there exist a delta greater +than zero such that + + align:start position:0% +than zero such that + + + align:start position:0% +than zero such that +if x - x0 + + align:start position:0% +if x - x0 + + + align:start position:0% +if x - x0 +is less than delta + + align:start position:0% +is less than delta + + + align:start position:0% +is less than delta +and again + + align:start position:0% +and again + + + align:start position:0% +and again +x is is assumed to be different from x0. + + align:start position:0% +x is is assumed to be different from x0. + + + align:start position:0% +x is is assumed to be different from x0. +If you have that then this difference + + align:start position:0% +If you have that then this difference + + + align:start position:0% +If you have that then this difference +quotient here + + align:start position:0% + + + + align:start position:0% + +minus this a + + align:start position:0% +minus this a + + + align:start position:0% +minus this a +is supposed to be less than epsilon. + + align:start position:0% +is supposed to be less than epsilon. + + + align:start position:0% +is supposed to be less than epsilon. +And so that's is + + align:start position:0% + + + + align:start position:0% + +okay. And so you see again in this + + align:start position:0% +okay. And so you see again in this + + + align:start position:0% +okay. And so you see again in this +example that we just looked at where uh + + align:start position:0% +example that we just looked at where uh + + + align:start position:0% +example that we just looked at where uh +in the example that we just looked at + + align:start position:0% +in the example that we just looked at + + + align:start position:0% +in the example that we just looked at +where uh so in the example + + align:start position:0% +where uh so in the example + + + align:start position:0% +where uh so in the example +where f ofx was equal to the absolute + + align:start position:0% +where f ofx was equal to the absolute + + + align:start position:0% +where f ofx was equal to the absolute +value of fx + + align:start position:0% +value of fx + + + align:start position:0% +value of fx +the if you were graphing it then this + + align:start position:0% +the if you were graphing it then this + + + align:start position:0% +the if you were graphing it then this +looks like this + + align:start position:0% +looks like this + + + align:start position:0% +looks like this +right and we saw that the difference + + align:start position:0% +right and we saw that the difference + + + align:start position:0% +right and we saw that the difference +quotion when you approach it over here, + + align:start position:0% +quotion when you approach it over here, + + + align:start position:0% +quotion when you approach it over here, +difference quotient was one. When you + + align:start position:0% +difference quotient was one. When you + + + align:start position:0% +difference quotient was one. When you +approach it over here, the difference + + align:start position:0% +approach it over here, the difference + + + align:start position:0% +approach it over here, the difference +quotient is minus one. So if you take a + + align:start position:0% +quotient is minus one. So if you take a + + + align:start position:0% +quotient is minus one. So if you take a +little any little interval around zero, + + align:start position:0% +little any little interval around zero, + + + align:start position:0% +little any little interval around zero, +then there the difference quotient could + + align:start position:0% +then there the difference quotient could + + + align:start position:0% +then there the difference quotient could +be either minus one or one, right? But + + align:start position:0% +be either minus one or one, right? But + + + align:start position:0% +be either minus one or one, right? But +even however small you make this little + + align:start position:0% +even however small you make this little + + + align:start position:0% +even however small you make this little +interval, it's not like that it converts + + align:start position:0% +interval, it's not like that it converts + + + align:start position:0% +interval, it's not like that it converts +to some number because it has it it is + + align:start position:0% +to some number because it has it it is + + + align:start position:0% +to some number because it has it it is +both you know they're both uh cases + + align:start position:0% +both you know they're both uh cases + + + align:start position:0% +both you know they're both uh cases +where it's one and cases where it's + + align:start position:0% +where it's one and cases where it's + + + align:start position:0% +where it's one and cases where it's +minus one. + + align:start position:0% +minus one. + + + align:start position:0% +minus one. +Okay. So that's that's like the first + + align:start position:0% +Okay. So that's that's like the first + + + align:start position:0% +Okay. So that's that's like the first +example + + align:start position:0% +example + + + align:start position:0% +example +and again you know of a function that is + + align:start position:0% +and again you know of a function that is + + + align:start position:0% +and again you know of a function that is +continuous + + align:start position:0% +continuous + + + align:start position:0% +continuous +but it's it's not differentiable as at + + align:start position:0% +but it's it's not differentiable as at + + + align:start position:0% +but it's it's not differentiable as at +zero. In this case it was a zero. + + align:start position:0% +zero. In this case it was a zero. + + + align:start position:0% +zero. In this case it was a zero. +Um and maybe a little bit more + + align:start position:0% +Um and maybe a little bit more + + + align:start position:0% +Um and maybe a little bit more +interesting example along the same line + + align:start position:0% +interesting example along the same line + + + align:start position:0% +interesting example along the same line +uh is uh the following. + + align:start position:0% + + + + align:start position:0% + +So + + align:start position:0% + + + + align:start position:0% + +So um if I so this is again a function + + align:start position:0% +So um if I so this is again a function + + + align:start position:0% +So um if I so this is again a function +on r into r + + align:start position:0% +on r into r + + + align:start position:0% +on r into r +and I said f ofx = x * sin of 1 /x. This + + align:start position:0% +and I said f ofx = x * sin of 1 /x. This + + + align:start position:0% +and I said f ofx = x * sin of 1 /x. This +here is not really defined at zero. So I + + align:start position:0% +here is not really defined at zero. So I + + + align:start position:0% +here is not really defined at zero. So I +need to define it also at zero. So when + + align:start position:0% +need to define it also at zero. So when + + + align:start position:0% +need to define it also at zero. So when +x is equal to zero then I just set it + + align:start position:0% +x is equal to zero then I just set it + + + align:start position:0% +x is equal to zero then I just set it +equal to + + align:start position:0% +equal to + + + align:start position:0% +equal to +to to zero and otherwise I set it equal + + align:start position:0% +to to zero and otherwise I set it equal + + + align:start position:0% +to to zero and otherwise I set it equal +to x * sin 1 /x okay + + align:start position:0% +to x * sin 1 /x okay + + + align:start position:0% +to x * sin 1 /x okay +and so the thing is that this function + + align:start position:0% +and so the thing is that this function + + + align:start position:0% +and so the thing is that this function +here so f here is continuous + + align:start position:0% + + + + align:start position:0% + +in particular it's continuous at x at at + + align:start position:0% +in particular it's continuous at x at at + + + align:start position:0% +in particular it's continuous at x at at +when at at zero it's continuous + + align:start position:0% +when at at zero it's continuous + + + align:start position:0% +when at at zero it's continuous +continuous it's actually continuous + + align:start position:0% +continuous it's actually continuous + + + align:start position:0% +continuous it's actually continuous +everywhere but but it's mostly + + align:start position:0% +everywhere but but it's mostly + + + align:start position:0% +everywhere but but it's mostly +interested in it at zero the graph of + + align:start position:0% +interested in it at zero the graph of + + + align:start position:0% +interested in it at zero the graph of +this to remember that sine function sine + + align:start position:0% +this to remember that sine function sine + + + align:start position:0% +this to remember that sine function sine +function looks like this that at zero + + align:start position:0% +function looks like this that at zero + + + align:start position:0% +function looks like this that at zero +um at zero + + align:start position:0% +um at zero + + + align:start position:0% +um at zero +at pi + + align:start position:0% +at pi + + + align:start position:0% +at pi +at 2 pi + + align:start position:0% +at 2 pi + + + align:start position:0% +at 2 pi +at 3 pi and so on at all of these + + align:start position:0% +at 3 pi and so on at all of these + + + align:start position:0% +at 3 pi and so on at all of these +by at all integer multiples also for the + + align:start position:0% +by at all integer multiples also for the + + + align:start position:0% +by at all integer multiples also for the +negative ones at all integer multiple of + + align:start position:0% +negative ones at all integer multiple of + + + align:start position:0% +negative ones at all integer multiple of +pi sign function vanishes + + align:start position:0% +pi sign function vanishes + + + align:start position:0% +pi sign function vanishes +and in between here it is at pi / two it + + align:start position:0% +and in between here it is at pi / two it + + + align:start position:0% +and in between here it is at pi / two it +achieves its maximum which is one and so + + align:start position:0% +achieves its maximum which is one and so + + + align:start position:0% +achieves its maximum which is one and so +the function looks like this + + align:start position:0% +the function looks like this + + + align:start position:0% +the function looks like this +so this here is one + + align:start position:0% + + + + align:start position:0% + +right that's how a sign function looks + + align:start position:0% + + + + align:start position:0% + +And so now if you're looking at sine of + + align:start position:0% +And so now if you're looking at sine of + + + align:start position:0% +And so now if you're looking at sine of +1 /x that's going to be a function as + + align:start position:0% +1 /x that's going to be a function as + + + align:start position:0% +1 /x that's going to be a function as +you're going down. So this is so if + + align:start position:0% +you're going down. So this is so if + + + align:start position:0% +you're going down. So this is so if +you're looking at this here was sine of + + align:start position:0% +you're looking at this here was sine of + + + align:start position:0% +you're looking at this here was sine of +x but if you're looking at sine of one + + align:start position:0% +x but if you're looking at sine of one + + + align:start position:0% +x but if you're looking at sine of one +of x as x go to zero this here becomes + + align:start position:0% +of x as x go to zero this here becomes + + + align:start position:0% +of x as x go to zero this here becomes +very large. So this means that as you're + + align:start position:0% +very large. So this means that as you're + + + align:start position:0% +very large. So this means that as you're +going to zero it go very rapidly through + + align:start position:0% +going to zero it go very rapidly through + + + align:start position:0% +going to zero it go very rapidly through +these periods where it goes where it's + + align:start position:0% +these periods where it goes where it's + + + align:start position:0% +these periods where it goes where it's +oscillates between minus1 and one the + + align:start position:0% +oscillates between minus1 and one the + + + align:start position:0% +oscillates between minus1 and one the +value here is minus one + + align:start position:0% + + + + align:start position:0% + +and so as you it will look like this + + align:start position:0% +and so as you it will look like this + + + align:start position:0% +and so as you it will look like this +that uh it will again uh if you're + + align:start position:0% +that uh it will again uh if you're + + + align:start position:0% +that uh it will again uh if you're +looking at it will again fluctu it will + + align:start position:0% +looking at it will again fluctu it will + + + align:start position:0% +looking at it will again fluctu it will +fluctuate but it will fluctuate operates + + align:start position:0% +fluctuate but it will fluctuate operates + + + align:start position:0% +fluctuate but it will fluctuate operates +uh much more rapidly. So if this here + + align:start position:0% +uh much more rapidly. So if this here + + + align:start position:0% +uh much more rapidly. So if this here +say was one over pi + + align:start position:0% + + + + align:start position:0% + +at one over pi 1 over 1 / pi is the same + + align:start position:0% +at one over pi 1 over 1 / pi is the same + + + align:start position:0% +at one over pi 1 over 1 / pi is the same +as pi there it would be zero and it + + align:start position:0% +as pi there it would be zero and it + + + align:start position:0% +as pi there it would be zero and it +would like fluctuate + + align:start position:0% +would like fluctuate + + + align:start position:0% +would like fluctuate +um it would fluctuate so it would look + + align:start position:0% +um it would fluctuate so it would look + + + align:start position:0% +um it would fluctuate so it would look +like something like this but it would + + align:start position:0% +like something like this but it would + + + align:start position:0% +like something like this but it would +fluctuate + + align:start position:0% + + + + align:start position:0% + +you know + + align:start position:0% +you know + + + align:start position:0% +you know +it and then as you're going way it will + + align:start position:0% +it and then as you're going way it will + + + align:start position:0% +it and then as you're going way it will +fluctuate less less often right so as + + align:start position:0% +fluctuate less less often right so as + + + align:start position:0% +fluctuate less less often right so as +you're going down towards zero it will + + align:start position:0% +you're going down towards zero it will + + + align:start position:0% +you're going down towards zero it will +fluctuate a lot right it always because + + align:start position:0% +fluctuate a lot right it always because + + + align:start position:0% +fluctuate a lot right it always because +sign always is between minus1 and one + + align:start position:0% +sign always is between minus1 and one + + + align:start position:0% +sign always is between minus1 and one +the value here will always between + + align:start position:0% +the value here will always between + + + align:start position:0% +the value here will always between +minus1 and one but as you're going + + align:start position:0% +minus1 and one but as you're going + + + align:start position:0% +minus1 and one but as you're going +towards zero from the right or from the + + align:start position:0% +towards zero from the right or from the + + + align:start position:0% +towards zero from the right or from the +left it's going to fluctuate more and + + align:start position:0% +left it's going to fluctuate more and + + + align:start position:0% +left it's going to fluctuate more and +more right as you're going away from + + align:start position:0% +more right as you're going away from + + + align:start position:0% +more right as you're going away from +zero is fluctuating less and less. + + align:start position:0% +zero is fluctuating less and less. + + + align:start position:0% +zero is fluctuating less and less. +Okay. So, so this is the function I'm + + align:start position:0% +Okay. So, so this is the function I'm + + + align:start position:0% +Okay. So, so this is the function I'm +interested in. And so, but when you + + align:start position:0% +interested in. And so, but when you + + + align:start position:0% +interested in. And so, but when you +multiply + + align:start position:0% + + + + align:start position:0% + +when you multiply through by X + + align:start position:0% +when you multiply through by X + + + align:start position:0% +when you multiply through by X +then you see when you multiply through + + align:start position:0% +then you see when you multiply through + + + align:start position:0% +then you see when you multiply through +by X it's fluctuating but it's always + + align:start position:0% +by X it's fluctuating but it's always + + + align:start position:0% +by X it's fluctuating but it's always +fluctuating between minus1 and one. If + + align:start position:0% +fluctuating between minus1 and one. If + + + align:start position:0% +fluctuating between minus1 and one. If +you + + align:start position:0% +you + + + align:start position:0% +you +multiply it by x then as you're going to + + align:start position:0% +multiply it by x then as you're going to + + + align:start position:0% +multiply it by x then as you're going to +zero this hair will squeeze down and it + + align:start position:0% +zero this hair will squeeze down and it + + + align:start position:0% +zero this hair will squeeze down and it +will become the fluctuation will be zero + + align:start position:0% +will become the fluctuation will be zero + + + align:start position:0% +will become the fluctuation will be zero +at zero. So it's easy to see that this + + align:start position:0% +at zero. So it's easy to see that this + + + align:start position:0% +at zero. So it's easy to see that this +function here so is indeed continuous. + + align:start position:0% +function here so is indeed continuous. + + + align:start position:0% +function here so is indeed continuous. +Right? + + align:start position:0% +Right? + + + align:start position:0% +Right? +But let's look at the difference + + align:start position:0% +But let's look at the difference + + + align:start position:0% +But let's look at the difference +quotient. So the difference quotient. + + align:start position:0% + + + + align:start position:0% + +So if we're looking at the difference + + align:start position:0% +So if we're looking at the difference + + + align:start position:0% +So if we're looking at the difference +quotion, so we're looking at and we just + + align:start position:0% +quotion, so we're looking at and we just + + + align:start position:0% +quotion, so we're looking at and we just +look at the difference quotient at zero. + + align:start position:0% +look at the difference quotient at zero. + + + align:start position:0% +look at the difference quotient at zero. +So this is the difference quotient + + align:start position:0% + + + + align:start position:0% + +and so it's x sin 1 /x. The value at + + align:start position:0% +and so it's x sin 1 /x. The value at + + + align:start position:0% +and so it's x sin 1 /x. The value at +zero by definition was zero. + + align:start position:0% + + + + align:start position:0% + +And so you see that now this here the x + + align:start position:0% +And so you see that now this here the x + + + align:start position:0% +And so you see that now this here the x +this here becomes just x sin 1 /x / x. + + align:start position:0% +this here becomes just x sin 1 /x / x. + + + align:start position:0% +this here becomes just x sin 1 /x / x. +And so you see that this here cancel + + align:start position:0% +And so you see that this here cancel + + + align:start position:0% +And so you see that this here cancel +with that. So you just get sine 1 /x. + + align:start position:0% +with that. So you just get sine 1 /x. + + + align:start position:0% +with that. So you just get sine 1 /x. +And so you see that now as x go to so + + align:start position:0% +And so you see that now as x go to so + + + align:start position:0% +And so you see that now as x go to so +when x here goes to zero + + align:start position:0% +when x here goes to zero + + + align:start position:0% +when x here goes to zero +this here fluctuates. This have + + align:start position:0% +this here fluctuates. This have + + + align:start position:0% +this here fluctuates. This have +fluctuate + + align:start position:0% + + + + align:start position:0% + +between + + align:start position:0% + + + + align:start position:0% + +minus one and one n1 + + align:start position:0% +minus one and one n1 + + + align:start position:0% +minus one and one n1 +but it doesn't have a limit right + + align:start position:0% +but it doesn't have a limit right + + + align:start position:0% +but it doesn't have a limit right +because it's fluctuated y or why not + + align:start position:0% +because it's fluctuated y or why not + + + align:start position:0% +because it's fluctuated y or why not +right. So this is a this is an example + + align:start position:0% +right. So this is a this is an example + + + align:start position:0% +right. So this is a this is an example +again this is another example of a + + align:start position:0% +again this is another example of a + + + align:start position:0% +again this is another example of a +function that is continuous + + align:start position:0% +function that is continuous + + + align:start position:0% +function that is continuous +at zero but not differentiable at zero. + + align:start position:0% +at zero but not differentiable at zero. + + + align:start position:0% +at zero but not differentiable at zero. +It's actually much worse than the + + align:start position:0% +It's actually much worse than the + + + align:start position:0% +It's actually much worse than the +previous the previous one was the + + align:start position:0% +previous the previous one was the + + + align:start position:0% +previous the previous one was the +previous one the example the + + align:start position:0% +previous one the example the + + + align:start position:0% +previous one the example the +previous example that was this example + + align:start position:0% +previous example that was this example + + + align:start position:0% +previous example that was this example +is much more tame. It is not + + align:start position:0% +is much more tame. It is not + + + align:start position:0% +is much more tame. It is not +differentiable at zero but if you were + + align:start position:0% +differentiable at zero but if you were + + + align:start position:0% +differentiable at zero but if you were +restrict to just positive things then + + align:start position:0% +restrict to just positive things then + + + align:start position:0% +restrict to just positive things then +from then it would be differentiable + + align:start position:0% +from then it would be differentiable + + + align:start position:0% +from then it would be differentiable +right if you were you could also define + + align:start position:0% +right if you were you could also define + + + align:start position:0% +right if you were you could also define +derivative. In general when we define + + align:start position:0% +derivative. In general when we define + + + align:start position:0% +derivative. In general when we define +derivative we let it be defined in a + + align:start position:0% +derivative we let it be defined in a + + + align:start position:0% +derivative we let it be defined in a +neighborhood of that point. So on either + + align:start position:0% +neighborhood of that point. So on either + + + align:start position:0% +neighborhood of that point. So on either +side. But if you were considering where + + align:start position:0% +side. But if you were considering where + + + align:start position:0% +side. But if you were considering where +you were allowing the function just to + + align:start position:0% +you were allowing the function just to + + + align:start position:0% +you were allowing the function just to +be defined at this point and then to the + + align:start position:0% +be defined at this point and then to the + + + align:start position:0% +be defined at this point and then to the +right say or to the left then this + + align:start position:0% +right say or to the left then this + + + align:start position:0% +right say or to the left then this +function would be differentiable. Right? + + align:start position:0% +function would be differentiable. Right? + + + align:start position:0% +function would be differentiable. Right? +But the in the in in in this example + + align:start position:0% +But the in the in in in this example + + + align:start position:0% +But the in the in in in this example +here it doesn't matter if you restrict + + align:start position:0% +here it doesn't matter if you restrict + + + align:start position:0% +here it doesn't matter if you restrict +the interval to just to the right or to + + align:start position:0% +the interval to just to the right or to + + + align:start position:0% +the interval to just to the right or to +the left. It's still not differential. + + align:start position:0% +the left. It's still not differential. + + + align:start position:0% +the left. It's still not differential. +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +Right. So this is something about this + + align:start position:0% +Right. So this is something about this + + + align:start position:0% +Right. So this is something about this +example is something about that it + + align:start position:0% +example is something about that it + + + align:start position:0% +example is something about that it +fluctuates wildly + + align:start position:0% +fluctuates wildly + + + align:start position:0% +fluctuates wildly +and that is causing it not to be + + align:start position:0% +and that is causing it not to be + + + align:start position:0% +and that is causing it not to be +differentiable. If it wasn't again if if + + align:start position:0% +differentiable. If it wasn't again if if + + + align:start position:0% +differentiable. If it wasn't again if if +you if you defined it if you didn't have + + align:start position:0% +you if you defined it if you didn't have + + + align:start position:0% +you if you defined it if you didn't have +this kind of the X here is sort of + + align:start position:0% +this kind of the X here is sort of + + + align:start position:0% +this kind of the X here is sort of +serving as some sort of it's dampening + + align:start position:0% +serving as some sort of it's dampening + + + align:start position:0% +serving as some sort of it's dampening +how much it's fluctuating right so if + + align:start position:0% +how much it's fluctuating right so if + + + align:start position:0% +how much it's fluctuating right so if +there wasn't a X here then this function + + align:start position:0% +there wasn't a X here then this function + + + align:start position:0% +there wasn't a X here then this function +wouldn't it would just fluctuate + + align:start position:0% +wouldn't it would just fluctuate + + + align:start position:0% +wouldn't it would just fluctuate +and it wouldn't even be continuous at X0 + + align:start position:0% +and it wouldn't even be continuous at X0 + + + align:start position:0% +and it wouldn't even be continuous at X0 +right but once I put this X on then it + + align:start position:0% +right but once I put this X on then it + + + align:start position:0% +right but once I put this X on then it +becomes continuous if I put another x. + + align:start position:0% +becomes continuous if I put another x. + + + align:start position:0% +becomes continuous if I put another x. +So if I'm looking at + + align:start position:0% +So if I'm looking at + + + align:start position:0% +So if I'm looking at +f ofx = x^2 * sin + + align:start position:0% +f ofx = x^2 * sin + + + align:start position:0% +f ofx = x^2 * sin +1 / x. Suppose I'm looking at this + + align:start position:0% +1 / x. Suppose I'm looking at this + + + align:start position:0% +1 / x. Suppose I'm looking at this +function. So now I have sort of dampened + + align:start position:0% +function. So now I have sort of dampened + + + align:start position:0% +function. So now I have sort of dampened +dampened the fluctuation even more. And + + align:start position:0% +dampened the fluctuation even more. And + + + align:start position:0% +dampened the fluctuation even more. And +so if I again looking at the difference + + align:start position:0% +so if I again looking at the difference + + + align:start position:0% +so if I again looking at the difference +quotient. So so I'm looking at this + + align:start position:0% +quotient. So so I'm looking at this + + + align:start position:0% +quotient. So so I'm looking at this +function maybe I should be more careful. + + align:start position:0% +function maybe I should be more careful. + + + align:start position:0% +function maybe I should be more careful. +So again at zero I need to define it + + align:start position:0% +So again at zero I need to define it + + + align:start position:0% +So again at zero I need to define it +separately. So I define a function + + align:start position:0% +separately. So I define a function + + + align:start position:0% +separately. So I define a function +that is zero at x = 0 and then it is x^2 + + align:start position:0% +that is zero at x = 0 and then it is x^2 + + + align:start position:0% +that is zero at x = 0 and then it is x^2 +* sin 1 /x otherwise + + align:start position:0% + + + + align:start position:0% + +if I'm looking at this function then I + + align:start position:0% +if I'm looking at this function then I + + + align:start position:0% +if I'm looking at this function then I +claim that this function is in fact uh + + align:start position:0% +claim that this function is in fact uh + + + align:start position:0% +claim that this function is in fact uh +French at x at zero and so let's look at + + align:start position:0% +French at x at zero and so let's look at + + + align:start position:0% +French at x at zero and so let's look at +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +So again, I'm looking at the difference + + align:start position:0% +So again, I'm looking at the difference + + + align:start position:0% +So again, I'm looking at the difference +quotient + + align:start position:0% +quotient + + + align:start position:0% +quotient +and the value at zero is zero. So I have + + align:start position:0% +and the value at zero is zero. So I have + + + align:start position:0% +and the value at zero is zero. So I have +this. + + align:start position:0% + + + + align:start position:0% + +And so this here is now just x² + + align:start position:0% +And so this here is now just x² + + + align:start position:0% +And so this here is now just x² +sin 1 /x. This thing here is then x. And + + align:start position:0% +sin 1 /x. This thing here is then x. And + + + align:start position:0% +sin 1 /x. This thing here is then x. And +so you see that this difference quotient + + align:start position:0% +so you see that this difference quotient + + + align:start position:0% +so you see that this difference quotient +is just this. But this here does + + align:start position:0% +is just this. But this here does + + + align:start position:0% +is just this. But this here does +converge to zero as x go to zero. + + align:start position:0% +converge to zero as x go to zero. + + + align:start position:0% +converge to zero as x go to zero. +Right? So this function is actually + + align:start position:0% +Right? So this function is actually + + + align:start position:0% +Right? So this function is actually +differentiable. Right? It's fluctuates + + align:start position:0% +differentiable. Right? It's fluctuates + + + align:start position:0% +differentiable. Right? It's fluctuates +but it's it's more mild the way it + + align:start position:0% +but it's it's more mild the way it + + + align:start position:0% +but it's it's more mild the way it +fluctuates. + + align:start position:0% +fluctuates. + + + align:start position:0% +fluctuates. +Okay. Now let me get back to the the + + align:start position:0% +Okay. Now let me get back to the the + + + align:start position:0% +Okay. Now let me get back to the the +rules. So we proved one uh rule that was + + align:start position:0% +rules. So we proved one uh rule that was + + + align:start position:0% +rules. So we proved one uh rule that was +this sum rule. + + align:start position:0% + + + + align:start position:0% + +Then the second rule we're interested in + + align:start position:0% +Then the second rule we're interested in + + + align:start position:0% +Then the second rule we're interested in +is when we're looking at the likeness + + align:start position:0% +is when we're looking at the likeness + + + align:start position:0% +is when we're looking at the likeness +rule. So we're looking at the product of + + align:start position:0% +rule. So we're looking at the product of + + + align:start position:0% +rule. So we're looking at the product of +these two functions and each function is + + align:start position:0% +these two functions and each function is + + + align:start position:0% +these two functions and each function is +assumed to be differentiable + + align:start position:0% +assumed to be differentiable + + + align:start position:0% +assumed to be differentiable +uh at x0 and then we claim that the + + align:start position:0% +uh at x0 and then we claim that the + + + align:start position:0% +uh at x0 and then we claim that the +product function is also differentiable + + align:start position:0% +product function is also differentiable + + + align:start position:0% +product function is also differentiable +at x0 and this is the formula for the + + align:start position:0% +at x0 and this is the formula for the + + + align:start position:0% +at x0 and this is the formula for the +derivative. Right? + + align:start position:0% +derivative. Right? + + + align:start position:0% +derivative. Right? +to prove this one here I need this fact + + align:start position:0% +to prove this one here I need this fact + + + align:start position:0% +to prove this one here I need this fact +that we have now proved that if it is + + align:start position:0% +that we have now proved that if it is + + + align:start position:0% +that we have now proved that if it is +defensible then it's also continuous at + + align:start position:0% +defensible then it's also continuous at + + + align:start position:0% +defensible then it's also continuous at +that point okay so I'm going to use that + + align:start position:0% +that point okay so I'm going to use that + + + align:start position:0% +that point okay so I'm going to use that +fact + + align:start position:0% +fact + + + align:start position:0% +fact +and so + + align:start position:0% +and so + + + align:start position:0% +and so +and now + + align:start position:0% + + + + align:start position:0% + +so so now so + + align:start position:0% +so so now so + + + align:start position:0% +so so now so +let's + + align:start position:0% +let's + + + align:start position:0% +let's +let's prove + + align:start position:0% + + + + align:start position:0% + +uh of lightness room. + + align:start position:0% + + + + align:start position:0% + +So we have uh these two functions. We're + + align:start position:0% +So we have uh these two functions. We're + + + align:start position:0% +So we have uh these two functions. We're +looking at f of x. We form the + + align:start position:0% +looking at f of x. We form the + + + align:start position:0% +looking at f of x. We form the +difference quotient. + + align:start position:0% + + + + align:start position:0% + +So this is the difference quotient x - + + align:start position:0% +So this is the difference quotient x - + + + align:start position:0% +So this is the difference quotient x - +x0 + + align:start position:0% + + + + align:start position:0% + +uh I I we do this trick that we've done + + align:start position:0% +uh I I we do this trick that we've done + + + align:start position:0% +uh I I we do this trick that we've done +a bunch of times before when we also + + align:start position:0% +a bunch of times before when we also + + + align:start position:0% +a bunch of times before when we also +looked at products. We had two sequences + + align:start position:0% +looked at products. We had two sequences + + + align:start position:0% +looked at products. We had two sequences +and we looked at the sequence that was + + align:start position:0% +and we looked at the sequence that was + + + align:start position:0% +and we looked at the sequence that was +the product of the these two. Right? So + + align:start position:0% +the product of the these two. Right? So + + + align:start position:0% +the product of the these two. Right? So +if you have just a reminder + + align:start position:0% +if you have just a reminder + + + align:start position:0% +if you have just a reminder +that I mean it's not like + + align:start position:0% + + + + align:start position:0% + +but but but + + align:start position:0% + + + + align:start position:0% + +so remember that if you had a sequence a + + align:start position:0% +so remember that if you had a sequence a + + + align:start position:0% +so remember that if you had a sequence a +n and a sequence bn and you knew that a + + align:start position:0% +n and a sequence bn and you knew that a + + + align:start position:0% +n and a sequence bn and you knew that a +n converts to a and bn converts to b + + align:start position:0% +n converts to a and bn converts to b + + + align:start position:0% +n converts to a and bn converts to b +then the product here converts to a * b. + + align:start position:0% +then the product here converts to a * b. + + + align:start position:0% +then the product here converts to a * b. +Right? So, and when we prove that we use + + align:start position:0% +Right? So, and when we prove that we use + + + align:start position:0% +Right? So, and when we prove that we use +this little trick with that we are uh + + align:start position:0% +this little trick with that we are uh + + + align:start position:0% +this little trick with that we are uh +we're splitting the difference between + + align:start position:0% +we're splitting the difference between + + + align:start position:0% +we're splitting the difference between +this and this. Right? And so I'm going + + align:start position:0% +this and this. Right? And so I'm going + + + align:start position:0% +this and this. Right? And so I'm going +to do exactly the same trick here. + + align:start position:0% +to do exactly the same trick here. + + + align:start position:0% +to do exactly the same trick here. +So I'm looking at this thing here. And + + align:start position:0% +So I'm looking at this thing here. And + + + align:start position:0% +So I'm looking at this thing here. And +so I write this thing here as f ofx * g + + align:start position:0% +so I write this thing here as f ofx * g + + + align:start position:0% +so I write this thing here as f ofx * g +ofx + + align:start position:0% +ofx + + + align:start position:0% +ofx +minus and it doesn't really matter + + align:start position:0% +minus and it doesn't really matter + + + align:start position:0% +minus and it doesn't really matter +you know where you're inserting it. So + + align:start position:0% +you know where you're inserting it. So + + + align:start position:0% +you know where you're inserting it. So +this here it's like splitting the + + align:start position:0% +this here it's like splitting the + + + align:start position:0% +this here it's like splitting the +difference and then I have to add it + + align:start position:0% +difference and then I have to add it + + + align:start position:0% +difference and then I have to add it +again. + + align:start position:0% + + + + align:start position:0% + +So this is certainly the same. I'm just + + align:start position:0% +So this is certainly the same. I'm just + + + align:start position:0% +So this is certainly the same. I'm just +subtracting it and adding it right back. + + align:start position:0% +subtracting it and adding it right back. + + + align:start position:0% +subtracting it and adding it right back. +And now I split this into two. So I + + align:start position:0% +And now I split this into two. So I + + + align:start position:0% +And now I split this into two. So I +write this in here. So I So this uh + + align:start position:0% +write this in here. So I So this uh + + + align:start position:0% +write this in here. So I So this uh +fraction I split into two. And the first + + align:start position:0% +fraction I split into two. And the first + + + align:start position:0% +fraction I split into two. And the first +one I take this one here together. So + + align:start position:0% +one I take this one here together. So + + + align:start position:0% +one I take this one here together. So +and you can factor out f ofx. You can + + align:start position:0% +and you can factor out f ofx. You can + + + align:start position:0% +and you can factor out f ofx. You can +write it like this. f of x - f of x0 + + align:start position:0% +write it like this. f of x - f of x0 + + + align:start position:0% +write it like this. f of x - f of x0 +x - x0 right so this is just right I'm + + align:start position:0% +x - x0 right so this is just right I'm + + + align:start position:0% +x - x0 right so this is just right I'm +just here I'm factoring out the g of x + + align:start position:0% +just here I'm factoring out the g of x + + + align:start position:0% +just here I'm factoring out the g of x +and then I'm left with this this is this + + align:start position:0% +and then I'm left with this this is this + + + align:start position:0% +and then I'm left with this this is this +and this is giving the denominator like + + align:start position:0% +and this is giving the denominator like + + + align:start position:0% +and this is giving the denominator like +that this is this part here and then I + + align:start position:0% +that this is this part here and then I + + + align:start position:0% +that this is this part here and then I +have the other part here but there you + + align:start position:0% +have the other part here but there you + + + align:start position:0% +have the other part here but there you +see that f of x0 is factoring out + + align:start position:0% + + + + align:start position:0% + +and then I have g of x minus g of x0 x - + + align:start position:0% +and then I have g of x minus g of x0 x - + + + align:start position:0% +and then I have g of x minus g of x0 x - +x0 + + align:start position:0% +x0 + + + align:start position:0% +x0 +like that. + + align:start position:0% +like that. + + + align:start position:0% +like that. +But now you see that as x goes to x0, + + align:start position:0% +But now you see that as x goes to x0, + + + align:start position:0% +But now you see that as x goes to x0, +right? Well, g was continuous at x0, + + align:start position:0% +right? Well, g was continuous at x0, + + + align:start position:0% +right? Well, g was continuous at x0, +right? So this thing here + + align:start position:0% +right? So this thing here + + + align:start position:0% +right? So this thing here +as x go to x0 this thing here goes to g + + align:start position:0% +as x go to x0 this thing here goes to g + + + align:start position:0% +as x go to x0 this thing here goes to g +of x0 right this one here that was + + align:start position:0% +of x0 right this one here that was + + + align:start position:0% +of x0 right this one here that was +because g was continuous because it was + + align:start position:0% +because g was continuous because it was + + + align:start position:0% +because g was continuous because it was +differentiable so it was also continuous + + align:start position:0% +differentiable so it was also continuous + + + align:start position:0% +differentiable so it was also continuous +this here goes to the derivative + + align:start position:0% + + + + align:start position:0% + +and the second thing here is this here + + align:start position:0% +and the second thing here is this here + + + align:start position:0% +and the second thing here is this here +is just constant + + align:start position:0% +is just constant + + + align:start position:0% +is just constant +and this here goes to the derivative + + align:start position:0% + + + + align:start position:0% + +like that + + align:start position:0% +like that + + + align:start position:0% +like that +right so we have so what we have proven + + align:start position:0% +right so we have so what we have proven + + + align:start position:0% +right so we have so what we have proven +is this here is as x goes to x0 + + align:start position:0% +is this here is as x goes to x0 + + + align:start position:0% +is this here is as x goes to x0 +so you see that we have proven that the + + align:start position:0% +so you see that we have proven that the + + + align:start position:0% +so you see that we have proven that the +difference this difference quotient here + + align:start position:0% +difference this difference quotient here + + + align:start position:0% +difference this difference quotient here +for the product + + align:start position:0% +for the product + + + align:start position:0% +for the product +has a limit and this is what the limit + + align:start position:0% +has a limit and this is what the limit + + + align:start position:0% +has a limit and this is what the limit +is right and so this means that the + + align:start position:0% +is right and so this means that the + + + align:start position:0% +is right and so this means that the +product is differentiable + + align:start position:0% +product is differentiable + + + align:start position:0% +product is differentiable +and this here is the derivative and + + align:start position:0% +and this here is the derivative and + + + align:start position:0% +and this here is the derivative and +that's exactly the this formula. Okay, + + align:start position:0% +that's exactly the this formula. Okay, + + + align:start position:0% +that's exactly the this formula. Okay, +which was this over here. This formula + + align:start position:0% +which was this over here. This formula + + + align:start position:0% +which was this over here. This formula +here. + + align:start position:0% + + + + align:start position:0% + +Okay, the next thing is that we uh want + + align:start position:0% +Okay, the next thing is that we uh want + + + align:start position:0% +Okay, the next thing is that we uh want +to prove the next rule is like this + + align:start position:0% +to prove the next rule is like this + + + align:start position:0% +to prove the next rule is like this +quotient rule. + + align:start position:0% +quotient rule. + + + align:start position:0% +quotient rule. +So let me prove the quotient rule. + + align:start position:0% + + + + align:start position:0% + +[Applause] + + align:start position:0% + + + + align:start position:0% + +So, Leness, right? Less and + + align:start position:0% +So, Leness, right? Less and + + + align:start position:0% +So, Leness, right? Less and +Leness and Newton was the one that was + + align:start position:0% +Leness and Newton was the one that was + + + align:start position:0% +Leness and Newton was the one that was +uh um um responsible for calculus. + + align:start position:0% + + + + align:start position:0% + +Uh and so then the next thing I want to + + align:start position:0% +Uh and so then the next thing I want to + + + align:start position:0% +Uh and so then the next thing I want to +prove is this quotion. + + align:start position:0% + + + + align:start position:0% + +And so again you have these two + + align:start position:0% +And so again you have these two + + + align:start position:0% +And so again you have these two +functions f and g + + align:start position:0% + + + + align:start position:0% + +and uh they are differentiable. + + align:start position:0% + + + + align:start position:0% + +at x0 and I'm also assuming that g here + + align:start position:0% +at x0 and I'm also assuming that g here + + + align:start position:0% +at x0 and I'm also assuming that g here +at x0 + + align:start position:0% +at x0 + + + align:start position:0% +at x0 +is is not equal to let's just assume + + align:start position:0% +is is not equal to let's just assume + + + align:start position:0% +is is not equal to let's just assume +that g is not equal to zero everywhere + + align:start position:0% +that g is not equal to zero everywhere + + + align:start position:0% +that g is not equal to zero everywhere +is never is is is is different from zero + + align:start position:0% +is never is is is is different from zero + + + align:start position:0% +is never is is is is different from zero +everywhere. + + align:start position:0% + + + + align:start position:0% + +And then the quotient rule say that if + + align:start position:0% +And then the quotient rule say that if + + + align:start position:0% +And then the quotient rule say that if +you're looking at the quotient here and + + align:start position:0% +you're looking at the quotient here and + + + align:start position:0% +you're looking at the quotient here and +you take the derivative of the so it say + + align:start position:0% +you take the derivative of the so it say + + + align:start position:0% +you take the derivative of the so it say +that if you're looking at the quotient + + align:start position:0% +that if you're looking at the quotient + + + align:start position:0% +that if you're looking at the quotient +here maybe I should so the quotion will + + align:start position:0% +here maybe I should so the quotion will + + + align:start position:0% +here maybe I should so the quotion will +say that that if you're looking at this + + align:start position:0% +say that that if you're looking at this + + + align:start position:0% +say that that if you're looking at this +thing here this now makes sense because + + align:start position:0% +thing here this now makes sense because + + + align:start position:0% +thing here this now makes sense because +g does not vanish + + align:start position:0% +g does not vanish + + + align:start position:0% +g does not vanish +This here is differentiable + + align:start position:0% + + + + align:start position:0% + +at x0. And the derivative + + align:start position:0% +at x0. And the derivative + + + align:start position:0% +at x0. And the derivative +the derivative of this function + + align:start position:0% +the derivative of this function + + + align:start position:0% +the derivative of this function +at x0 + + align:start position:0% +at x0 + + + align:start position:0% +at x0 +is given by the following formula that + + align:start position:0% +is given by the following formula that + + + align:start position:0% +is given by the following formula that +it is the derivative of f at x0 time g + + align:start position:0% +it is the derivative of f at x0 time g + + + align:start position:0% +it is the derivative of f at x0 time g +of x0 + + align:start position:0% +of x0 + + + align:start position:0% +of x0 +minus uh um f at x0 * g prime at x0 + + align:start position:0% +minus uh um f at x0 * g prime at x0 + + + align:start position:0% +minus uh um f at x0 * g prime at x0 +divided by G G² so G of X0 times itself + + align:start position:0% +divided by G G² so G of X0 times itself + + + align:start position:0% +divided by G G² so G of X0 times itself +I'll write that as a square this + + align:start position:0% + + + + align:start position:0% + +here again this here this here is just g + + align:start position:0% +here again this here this here is just g + + + align:start position:0% +here again this here this here is just g +of X0 * G of X0 + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so now let's try to prove + + align:start position:0% + + + + align:start position:0% + +So we're looking at f ofx f like this at + + align:start position:0% +So we're looking at f ofx f like this at + + + align:start position:0% +So we're looking at f ofx f like this at +x minus. So this is the difference + + align:start position:0% +x minus. So this is the difference + + + align:start position:0% +x minus. So this is the difference +quotient + + align:start position:0% +quotient + + + align:start position:0% +quotient +at x0 divided by x - x0, right? That's + + align:start position:0% +at x0 divided by x - x0, right? That's + + + align:start position:0% +at x0 divided by x - x0, right? That's +the difference quotion. And so written + + align:start position:0% +the difference quotion. And so written + + + align:start position:0% +the difference quotion. And so written +out this is f of x + + align:start position:0% +out this is f of x + + + align:start position:0% +out this is f of x +g of x + + align:start position:0% +g of x + + + align:start position:0% +g of x +minus + + align:start position:0% +minus + + + align:start position:0% +minus +g uh f sorry f of x0 + + align:start position:0% +g uh f sorry f of x0 + + + align:start position:0% +g uh f sorry f of x0 +divided by g of x0 + + align:start position:0% +divided by g of x0 + + + align:start position:0% +divided by g of x0 +x - x0. So let me put this on a with on + + align:start position:0% +x - x0. So let me put this on a with on + + + align:start position:0% +x - x0. So let me put this on a with on +a fraction with a common denominator. So + + align:start position:0% +a fraction with a common denominator. So + + + align:start position:0% +a fraction with a common denominator. So +if I do that then this thing here is + + align:start position:0% +if I do that then this thing here is + + + align:start position:0% +if I do that then this thing here is +right. So then I'm multiplying + + align:start position:0% +right. So then I'm multiplying + + + align:start position:0% +right. So then I'm multiplying +uh by g of x0 both in the denominator + + align:start position:0% +uh by g of x0 both in the denominator + + + align:start position:0% +uh by g of x0 both in the denominator +and denominator here. So I'm getting f + + align:start position:0% +and denominator here. So I'm getting f + + + align:start position:0% +and denominator here. So I'm getting f +of x + + align:start position:0% +of x + + + align:start position:0% +of x +times g of x0 + + align:start position:0% +times g of x0 + + + align:start position:0% +times g of x0 +and then here I'm multiplying by g of x + + align:start position:0% +and then here I'm multiplying by g of x + + + align:start position:0% +and then here I'm multiplying by g of x +in both denominator and denominator. So + + align:start position:0% +in both denominator and denominator. So + + + align:start position:0% +in both denominator and denominator. So +getting this thing here + + align:start position:0% +getting this thing here + + + align:start position:0% +getting this thing here +g of x and then it becomes x - x0 + + align:start position:0% +g of x and then it becomes x - x0 + + + align:start position:0% +g of x and then it becomes x - x0 +and then g of x g of x0 + + align:start position:0% +and then g of x g of x0 + + + align:start position:0% +and then g of x g of x0 +like that. + + align:start position:0% + + + + align:start position:0% + +And so now you can write this thing here + + align:start position:0% +And so now you can write this thing here + + + align:start position:0% +And so now you can write this thing here +uh as right. And so now you do the same + + align:start position:0% +uh as right. And so now you do the same + + + align:start position:0% +uh as right. And so now you do the same +trick uh as before. + + align:start position:0% +trick uh as before. + + + align:start position:0% +trick uh as before. +I mean I could have I could have gotten + + align:start position:0% +I mean I could have I could have gotten + + + align:start position:0% +I mean I could have I could have gotten +away uh slightly easier with looking at + + align:start position:0% +away uh slightly easier with looking at + + + align:start position:0% +away uh slightly easier with looking at +a special case of this quotion rule + + align:start position:0% +a special case of this quotion rule + + + align:start position:0% +a special case of this quotion rule +where f was a constant function one. So + + align:start position:0% +where f was a constant function one. So + + + align:start position:0% +where f was a constant function one. So +I could do that first and then the + + align:start position:0% +I could do that first and then the + + + align:start position:0% +I could do that first and then the +general case I could then from get from + + align:start position:0% +general case I could then from get from + + + align:start position:0% +general case I could then from get from +this special case together with the + + align:start position:0% +this special case together with the + + + align:start position:0% +this special case together with the +lens. But I chose to it's most often + + align:start position:0% +lens. But I chose to it's most often + + + align:start position:0% +lens. But I chose to it's most often +they want to do it together anyway. But + + align:start position:0% +they want to do it together anyway. But + + + align:start position:0% +they want to do it together anyway. But +if you have to do it together, you have + + align:start position:0% +if you have to do it together, you have + + + align:start position:0% +if you have to do it together, you have +to use the same trick that we just did. + + align:start position:0% +to use the same trick that we just did. + + + align:start position:0% +to use the same trick that we just did. +So we're using + + align:start position:0% + + + + align:start position:0% + +uh that over here. + + align:start position:0% +uh that over here. + + + align:start position:0% +uh that over here. +So uh + + align:start position:0% +So uh + + + align:start position:0% +So uh +so f ofx + + align:start position:0% +so f ofx + + + align:start position:0% +so f ofx +g of x0 + + align:start position:0% +g of x0 + + + align:start position:0% +g of x0 +minus uh and then uh f of uh f of x0 + + align:start position:0% +minus uh and then uh f of uh f of x0 + + + align:start position:0% +minus uh and then uh f of uh f of x0 +g of x0 + + align:start position:0% + + + + align:start position:0% + +plus uh f of x0 + + align:start position:0% +plus uh f of x0 + + + align:start position:0% +plus uh f of x0 +g of x0 + + align:start position:0% +g of x0 + + + align:start position:0% +g of x0 +uh minus f(x) + + align:start position:0% +uh minus f(x) + + + align:start position:0% +uh minus f(x) +g of x. So this is again where I'm + + align:start position:0% +g of x. So this is again where I'm + + + align:start position:0% +g of x. So this is again where I'm +subtracting in the denominator something + + align:start position:0% +subtracting in the denominator something + + + align:start position:0% +subtracting in the denominator something +and then I'm adding it back up + + align:start position:0% +and then I'm adding it back up + + + align:start position:0% +and then I'm adding it back up +immediately. + + align:start position:0% +immediately. + + + align:start position:0% +immediately. +So I have this + + align:start position:0% + + + + align:start position:0% + +like that. + + align:start position:0% + + + + align:start position:0% + +And so now uh if you do that then you + + align:start position:0% +And so now uh if you do that then you + + + align:start position:0% +And so now uh if you do that then you +see that. So now you can and now you + + align:start position:0% +see that. So now you can and now you + + + align:start position:0% +see that. So now you can and now you +split it up again into two fractions. + + align:start position:0% +split it up again into two fractions. + + + align:start position:0% +split it up again into two fractions. +So we split it up + + align:start position:0% +So we split it up + + + align:start position:0% +So we split it up +and so this thing here this thing here + + align:start position:0% +and so this thing here this thing here + + + align:start position:0% +and so this thing here this thing here +but there you see that there's a g of x0 + + align:start position:0% +but there you see that there's a g of x0 + + + align:start position:0% +but there you see that there's a g of x0 +that factor out. So this is equal to g + + align:start position:0% +that factor out. So this is equal to g + + + align:start position:0% +that factor out. So this is equal to g +of x0 and then you have f ofx minus f of + + align:start position:0% +of x0 and then you have f ofx minus f of + + + align:start position:0% +of x0 and then you have f ofx minus f of +x0 + + align:start position:0% +x0 + + + align:start position:0% +x0 +and then x - x0 + + align:start position:0% +and then x - x0 + + + align:start position:0% +and then x - x0 +g of x + + align:start position:0% +g of x + + + align:start position:0% +g of x +g of x0 like that. + + align:start position:0% +g of x0 like that. + + + align:start position:0% +g of x0 like that. +And for the second one, see that there + + align:start position:0% +And for the second one, see that there + + + align:start position:0% +And for the second one, see that there +you there you also have something that's + + align:start position:0% +you there you also have something that's + + + align:start position:0% +you there you also have something that's +factor out. And this is f of x0 + + align:start position:0% +factor out. And this is f of x0 + + + align:start position:0% +factor out. And this is f of x0 +like that. + + align:start position:0% +like that. + + + align:start position:0% +like that. +And you're getting g of u of x0 + + align:start position:0% +And you're getting g of u of x0 + + + align:start position:0% +And you're getting g of u of x0 +minus g of x + + align:start position:0% +minus g of x + + + align:start position:0% +minus g of x +over + + align:start position:0% +over + + + align:start position:0% +over +um x - x0. + + align:start position:0% +um x - x0. + + + align:start position:0% +um x - x0. +uh g of x + + align:start position:0% +uh g of x + + + align:start position:0% +uh g of x +g of x here like that. + + align:start position:0% +g of x here like that. + + + align:start position:0% +g of x here like that. +And now okay so now I can make this + + align:start position:0% +And now okay so now I can make this + + + align:start position:0% +And now okay so now I can make this +looks nicer. I can this one here cancel + + align:start position:0% +looks nicer. I can this one here cancel + + + align:start position:0% +looks nicer. I can this one here cancel +with that. + + align:start position:0% +with that. + + + align:start position:0% +with that. +And so I can write this thing here as 1 + + align:start position:0% +And so I can write this thing here as 1 + + + align:start position:0% +And so I can write this thing here as 1 +/ g of x + + align:start position:0% +/ g of x + + + align:start position:0% +/ g of x +f ofx + + align:start position:0% +f ofx + + + align:start position:0% +f ofx +- f of x0 + + align:start position:0% +- f of x0 + + + align:start position:0% +- f of x0 +/ x - x0. So this take care of this. + + align:start position:0% +/ x - x0. So this take care of this. + + + align:start position:0% +/ x - x0. So this take care of this. +Here I can um here I can um I will write + + align:start position:0% +Here I can um here I can um I will write + + + align:start position:0% +Here I can um here I can um I will write +it as I will take this one here out. So + + align:start position:0% +it as I will take this one here out. So + + + align:start position:0% +it as I will take this one here out. So +I'll write it as f of x0 + + align:start position:0% +I'll write it as f of x0 + + + align:start position:0% +I'll write it as f of x0 +g of x + + align:start position:0% +g of x + + + align:start position:0% +g of x +time g of x0. + + align:start position:0% +time g of x0. + + + align:start position:0% +time g of x0. +And then I'm left with this thing here. + + align:start position:0% +And then I'm left with this thing here. + + + align:start position:0% +And then I'm left with this thing here. +And what I don't love about this thing + + align:start position:0% +And what I don't love about this thing + + + align:start position:0% +And what I don't love about this thing +here is it's not quite the difference + + align:start position:0% +here is it's not quite the difference + + + align:start position:0% +here is it's not quite the difference +quotient because the order of these two + + align:start position:0% +quotient because the order of these two + + + align:start position:0% +quotient because the order of these two +is wrong. So I switch the order. But if + + align:start position:0% +is wrong. So I switch the order. But if + + + align:start position:0% +is wrong. So I switch the order. But if +I switch the order then I have to + + align:start position:0% +I switch the order then I have to + + + align:start position:0% +I switch the order then I have to +pick up a minus sign. So I get minus + + align:start position:0% +pick up a minus sign. So I get minus + + + align:start position:0% +pick up a minus sign. So I get minus +here. And now it is g of x + + align:start position:0% +here. And now it is g of x + + + align:start position:0% +here. And now it is g of x +g of x0 + + align:start position:0% +g of x0 + + + align:start position:0% +g of x0 +x - x0 like that. + + align:start position:0% +x - x0 like that. + + + align:start position:0% +x - x0 like that. +Okay. And now you see that as x so as x + + align:start position:0% +Okay. And now you see that as x so as x + + + align:start position:0% +Okay. And now you see that as x so as x +goes to x0 + + align:start position:0% +goes to x0 + + + align:start position:0% +goes to x0 +so now as x + + align:start position:0% +so now as x + + + align:start position:0% +so now as x +goes to x0 + + align:start position:0% +goes to x0 + + + align:start position:0% +goes to x0 +well this one here the function was + + align:start position:0% +well this one here the function was + + + align:start position:0% +well this one here the function was +differentiable so it's also continuous. + + align:start position:0% +differentiable so it's also continuous. + + + align:start position:0% +differentiable so it's also continuous. +So this goes to 1 / g of x0. + + align:start position:0% +So this goes to 1 / g of x0. + + + align:start position:0% +So this goes to 1 / g of x0. +This one here just goes to the + + align:start position:0% +This one here just goes to the + + + align:start position:0% +This one here just goes to the +derivative + + align:start position:0% +derivative + + + align:start position:0% +derivative +at x0. + + align:start position:0% +at x0. + + + align:start position:0% +at x0. +This one here goes to again because the + + align:start position:0% +This one here goes to again because the + + + align:start position:0% +This one here goes to again because the +function is continuous. This goes to + + align:start position:0% +function is continuous. This goes to + + + align:start position:0% +function is continuous. This goes to +minus f of x0 + + align:start position:0% +minus f of x0 + + + align:start position:0% +minus f of x0 +and then it's what I wrote before as d² + + align:start position:0% +and then it's what I wrote before as d² + + + align:start position:0% +and then it's what I wrote before as d² +is d of x0 * itself. + + align:start position:0% + + + + align:start position:0% + +And then this in here goes to the + + align:start position:0% +And then this in here goes to the + + + align:start position:0% +And then this in here goes to the +derivative of x0 at zero. + + align:start position:0% +derivative of x0 at zero. + + + align:start position:0% +derivative of x0 at zero. +Right? And now I can if I want to I can + + align:start position:0% +Right? And now I can if I want to I can + + + align:start position:0% +Right? And now I can if I want to I can +rewrite this in here. If I want to put + + align:start position:0% +rewrite this in here. If I want to put + + + align:start position:0% +rewrite this in here. If I want to put +it back on a common denominator, then I + + align:start position:0% +it back on a common denominator, then I + + + align:start position:0% +it back on a common denominator, then I +have to multiply in the nominator and + + align:start position:0% +have to multiply in the nominator and + + + align:start position:0% +have to multiply in the nominator and +denominator by g of x0. If I do this, I + + align:start position:0% +denominator by g of x0. If I do this, I + + + align:start position:0% +denominator by g of x0. If I do this, I +get f prime of x0 g of x0 + + align:start position:0% +get f prime of x0 g of x0 + + + align:start position:0% +get f prime of x0 g of x0 +and then I get g^2 of x0 in the + + align:start position:0% +and then I get g^2 of x0 in the + + + align:start position:0% +and then I get g^2 of x0 in the +denominator. And then here it's just + + align:start position:0% +denominator. And then here it's just + + + align:start position:0% +denominator. And then here it's just +those two minus f of x0 + + align:start position:0% +those two minus f of x0 + + + align:start position:0% +those two minus f of x0 +g prime of x0. + + align:start position:0% +g prime of x0. + + + align:start position:0% +g prime of x0. +And so you see that this here is exactly + + align:start position:0% +And so you see that this here is exactly + + + align:start position:0% +And so you see that this here is exactly +this formula here this this quotion rule + + align:start position:0% +this formula here this this quotion rule + + + align:start position:0% +this formula here this this quotion rule +right. So this proof that if you take + + align:start position:0% +right. So this proof that if you take + + + align:start position:0% +right. So this proof that if you take +two functions the the one you have in + + align:start position:0% +two functions the the one you have in + + + align:start position:0% +two functions the the one you have in +the denominator if that is non vanishing + + align:start position:0% +the denominator if that is non vanishing + + + align:start position:0% +the denominator if that is non vanishing +so you can form the quotient and if each + + align:start position:0% +so you can form the quotient and if each + + + align:start position:0% +so you can form the quotient and if each +of these two functions is differentiable + + align:start position:0% +of these two functions is differentiable + + + align:start position:0% +of these two functions is differentiable +then the quotient is also differentiable + + align:start position:0% +then the quotient is also differentiable + + + align:start position:0% +then the quotient is also differentiable +and this is the formula for the + + align:start position:0% +and this is the formula for the + + + align:start position:0% +and this is the formula for the +derivative + + align:start position:0% +derivative + + + align:start position:0% +derivative +right so now why is this already really + + align:start position:0% +right so now why is this already really + + + align:start position:0% +right so now why is this already really +really useful + + align:start position:0% +really useful + + + align:start position:0% +really useful +so + + align:start position:0% + + + + align:start position:0% + +so We calculated + + align:start position:0% +so We calculated + + + align:start position:0% +so We calculated +we already we calculated so we started + + align:start position:0% +we already we calculated so we started + + + align:start position:0% +we already we calculated so we started +with the example of where f is a + + align:start position:0% +with the example of where f is a + + + align:start position:0% +with the example of where f is a +constant right and we saw that it's + + align:start position:0% +constant right and we saw that it's + + + align:start position:0% +constant right and we saw that it's +differentiable and the derivative is + + align:start position:0% +differentiable and the derivative is + + + align:start position:0% +differentiable and the derivative is +zero. Then the second example we had was + + align:start position:0% +zero. Then the second example we had was + + + align:start position:0% +zero. Then the second example we had was +where the function was x and we saw that + + align:start position:0% +where the function was x and we saw that + + + align:start position:0% +where the function was x and we saw that +it was differentiable and the derivative + + align:start position:0% +it was differentiable and the derivative + + + align:start position:0% +it was differentiable and the derivative +is one. Right? If you now take um if you + + align:start position:0% +is one. Right? If you now take um if you + + + align:start position:0% +is one. Right? If you now take um if you +now take ax + + align:start position:0% +now take ax + + + align:start position:0% +now take ax +times uh right so let's just take ax as + + align:start position:0% +times uh right so let's just take ax as + + + align:start position:0% +times uh right so let's just take ax as +the next example + + align:start position:0% +the next example + + + align:start position:0% +the next example +this is like a constant function times + + align:start position:0% +this is like a constant function times + + + align:start position:0% +this is like a constant function times +this function so light rule sorry if f + + align:start position:0% +this function so light rule sorry if f + + + align:start position:0% +this function so light rule sorry if f +ofx is equal to a * x where a is a + + align:start position:0% +ofx is equal to a * x where a is a + + + align:start position:0% +ofx is equal to a * x where a is a +constant lightn will say that the + + align:start position:0% +constant lightn will say that the + + + align:start position:0% +constant lightn will say that the +product of two differentiable functions + + align:start position:0% +product of two differentiable functions + + + align:start position:0% +product of two differentiable functions +is differentiable and the derivative of + + align:start position:0% +is differentiable and the derivative of + + + align:start position:0% +is differentiable and the derivative of +This is the derivative of that, but the + + align:start position:0% +This is the derivative of that, but the + + + align:start position:0% +This is the derivative of that, but the +derivative of that does a constant + + align:start position:0% +derivative of that does a constant + + + align:start position:0% +derivative of that does a constant +function. So that's zero. So I don't + + align:start position:0% +function. So that's zero. So I don't + + + align:start position:0% +function. So that's zero. So I don't +really have to think about that. So it's + + align:start position:0% +really have to think about that. So it's + + + align:start position:0% +really have to think about that. So it's +just the a times the derivative of the + + align:start position:0% +just the a times the derivative of the + + + align:start position:0% +just the a times the derivative of the +second function, but that's one. So this + + align:start position:0% +second function, but that's one. So this + + + align:start position:0% +second function, but that's one. So this +here is the derivative of that. + + align:start position:0% +here is the derivative of that. + + + align:start position:0% +here is the derivative of that. +Right? So and the next example would be + + align:start position:0% +Right? So and the next example would be + + + align:start position:0% +Right? So and the next example would be +that you're looking at a x plus say b f + + align:start position:0% +that you're looking at a x plus say b f + + + align:start position:0% +that you're looking at a x plus say b f +of x is equal to this. Then you can use + + align:start position:0% +of x is equal to this. Then you can use + + + align:start position:0% +of x is equal to this. Then you can use +the sum + + align:start position:0% +the sum + + + align:start position:0% +the sum +plus you know we know what each of these + + align:start position:0% +plus you know we know what each of these + + + align:start position:0% +plus you know we know what each of these +is. So you get that this one here is + + align:start position:0% +is. So you get that this one here is + + + align:start position:0% +is. So you get that this one here is +also differentiable and the derivative + + align:start position:0% +also differentiable and the derivative + + + align:start position:0% +also differentiable and the derivative +of this function here is also just a and + + align:start position:0% +of this function here is also just a and + + + align:start position:0% +of this function here is also just a and +and you can continue like this that if + + align:start position:0% +and you can continue like this that if + + + align:start position:0% +and you can continue like this that if +you take + + align:start position:0% +you take + + + align:start position:0% +you take +um if you use if you now have a polomial + + align:start position:0% +um if you use if you now have a polomial + + + align:start position:0% +um if you use if you now have a polomial +suppose you take a to the power n so f + + align:start position:0% +suppose you take a to the power n so f + + + align:start position:0% +suppose you take a to the power n so f +of sorry uh if f of x is x to the^ n + + align:start position:0% +of sorry uh if f of x is x to the^ n + + + align:start position:0% +of sorry uh if f of x is x to the^ n +then you can think about this thing here + + align:start position:0% +then you can think about this thing here + + + align:start position:0% +then you can think about this thing here +as x * X * X * X + + align:start position:0% +as x * X * X * X + + + align:start position:0% +as x * X * X * X +and you can use the lieness rule right + + align:start position:0% +and you can use the lieness rule right + + + align:start position:0% +and you can use the lieness rule right +and so if you use the leness rule so you + + align:start position:0% +and so if you use the leness rule so you + + + align:start position:0% +and so if you use the leness rule so you +just do it first in the case where f ofx + + align:start position:0% +just do it first in the case where f ofx + + + align:start position:0% +just do it first in the case where f ofx +is equal to x^2 you can think about this + + align:start position:0% +is equal to x^2 you can think about this + + + align:start position:0% +is equal to x^2 you can think about this +as x * x these are two differentiable + + align:start position:0% +as x * x these are two differentiable + + + align:start position:0% +as x * x these are two differentiable +functions so the derivative here is now + + align:start position:0% +functions so the derivative here is now + + + align:start position:0% +functions so the derivative here is now +the derivative of this so that's 1 times + + align:start position:0% +the derivative of this so that's 1 times + + + align:start position:0% +the derivative of this so that's 1 times +the other function plus you keep this + + align:start position:0% +the other function plus you keep this + + + align:start position:0% +the other function plus you keep this +one here and you take the derivative of + + align:start position:0% +one here and you take the derivative of + + + align:start position:0% +one here and you take the derivative of +that. So this is this. So this is 2 * x, + + align:start position:0% +that. So this is this. So this is 2 * x, + + + align:start position:0% +that. So this is this. So this is 2 * x, +right? And so if you take this function + + align:start position:0% +right? And so if you take this function + + + align:start position:0% +right? And so if you take this function +here using lightness rule, + + align:start position:0% +here using lightness rule, + + + align:start position:0% +here using lightness rule, +in this case the derivative it's + + align:start position:0% +in this case the derivative it's + + + align:start position:0% +in this case the derivative it's +differentiable and the derivative + + align:start position:0% +differentiable and the derivative + + + align:start position:0% +differentiable and the derivative +is uh n * x ^ nus one. Right? + + align:start position:0% +is uh n * x ^ nus one. Right? + + + align:start position:0% +is uh n * x ^ nus one. Right? +So that's so so and and in fact find + + align:start position:0% +So that's so so and and in fact find + + + align:start position:0% +So that's so so and and in fact find +even more generally + + align:start position:0% +even more generally + + + align:start position:0% +even more generally +you know just using the sum and the + + align:start position:0% +you know just using the sum and the + + + align:start position:0% +you know just using the sum and the +likeness rule if you take any + + align:start position:0% +likeness rule if you take any + + + align:start position:0% +likeness rule if you take any +if you take any polomium a n x n + a n + + align:start position:0% +if you take any polomium a n x n + a n + + + align:start position:0% +if you take any polomium a n x n + a n +-1 x n minus one + + align:start position:0% +-1 x n minus one + + + align:start position:0% +-1 x n minus one +down to + + align:start position:0% +down to + + + align:start position:0% +down to +the last sign is being a constant. If + + align:start position:0% +the last sign is being a constant. If + + + align:start position:0% +the last sign is being a constant. If +you take a polinomial like this just + + align:start position:0% +you take a polinomial like this just + + + align:start position:0% +you take a polinomial like this just +using the lieness rule and the sum rule + + align:start position:0% +using the lieness rule and the sum rule + + + align:start position:0% +using the lieness rule and the sum rule +using those repeatedly + + align:start position:0% +using those repeatedly + + + align:start position:0% +using those repeatedly +we know that this here is differentiable + + align:start position:0% +we know that this here is differentiable + + + align:start position:0% +we know that this here is differentiable +and the derivative is just like the sum + + align:start position:0% +and the derivative is just like the sum + + + align:start position:0% +and the derivative is just like the sum +of the derivative of these. So this is + + align:start position:0% +of the derivative of these. So this is + + + align:start position:0% +of the derivative of these. So this is +going to be a n * n * x ^ n -1 + + align:start position:0% +going to be a n * n * x ^ n -1 + + + align:start position:0% +going to be a n * n * x ^ n -1 ++ n -1 * a n -1 x n - 2 + + align:start position:0% ++ n -1 * a n -1 x n - 2 + + + align:start position:0% ++ n -1 * a n -1 x n - 2 +and then the this one here the + + align:start position:0% +and then the this one here the + + + align:start position:0% +and then the this one here the +derivative is zero. So the last one + + align:start position:0% +derivative is zero. So the last one + + + align:start position:0% +derivative is zero. So the last one +you're getting something non-trivial for + + align:start position:0% +you're getting something non-trivial for + + + align:start position:0% +you're getting something non-trivial for +is a one + + align:start position:0% +is a one + + + align:start position:0% +is a one +right. So this is just using sum and + + align:start position:0% +right. So this is just using sum and + + + align:start position:0% +right. So this is just using sum and +license room. + + align:start position:0% +license room. + + + align:start position:0% +license room. +And so this is just using + + align:start position:0% + + + + align:start position:0% + +the sum + + align:start position:0% +the sum + + + align:start position:0% +the sum +plus lightness room + + align:start position:0% + + + + align:start position:0% + +repeatedly. + + align:start position:0% + + + + align:start position:0% + +Okay. Now likewise if you take a + + align:start position:0% +Okay. Now likewise if you take a + + + align:start position:0% +Okay. Now likewise if you take a +rational function so meaning that if you + + align:start position:0% +rational function so meaning that if you + + + align:start position:0% +rational function so meaning that if you +take something if f ofx + + align:start position:0% +take something if f ofx + + + align:start position:0% +take something if f ofx +is equal to some polomium + + align:start position:0% +is equal to some polomium + + + align:start position:0% +is equal to some polomium +a polomial + + align:start position:0% +a polomial + + + align:start position:0% +a polomial +so it's called p + + align:start position:0% +so it's called p + + + align:start position:0% +so it's called p +of x divided by uh q of x. So where this + + align:start position:0% +of x divided by uh q of x. So where this + + + align:start position:0% +of x divided by uh q of x. So where this +here is a polinomial + + align:start position:0% + + + + align:start position:0% + +and and and so is that right? So now you + + align:start position:0% +and and and so is that right? So now you + + + align:start position:0% +and and and so is that right? So now you +can use the uh the quotient rule right. + + align:start position:0% + + + + align:start position:0% + +So the quotient rule will tell you that + + align:start position:0% +So the quotient rule will tell you that + + + align:start position:0% +So the quotient rule will tell you that +as long as you are looking at point + + align:start position:0% +as long as you are looking at point + + + align:start position:0% +as long as you are looking at point +where this here does not vanish. So then + + align:start position:0% +where this here does not vanish. So then + + + align:start position:0% +where this here does not vanish. So then +the quotient here is also differentiable + + align:start position:0% +the quotient here is also differentiable + + + align:start position:0% +the quotient here is also differentiable +and it gives you a formula for the + + align:start position:0% +and it gives you a formula for the + + + align:start position:0% +and it gives you a formula for the +derivative in terms of the derivative of + + align:start position:0% +derivative in terms of the derivative of + + + align:start position:0% +derivative in terms of the derivative of +each of these two and each of those two + + align:start position:0% +each of these two and each of those two + + + align:start position:0% +each of these two and each of those two +they can be calculated like that. + + align:start position:0% +they can be calculated like that. + + + align:start position:0% +they can be calculated like that. +So you see it's already already now we + + align:start position:0% +So you see it's already already now we + + + align:start position:0% +So you see it's already already now we +have like quite the derivative of a lot + + align:start position:0% +have like quite the derivative of a lot + + + align:start position:0% +have like quite the derivative of a lot +of functions right we have of all + + align:start position:0% +of functions right we have of all + + + align:start position:0% +of functions right we have of all +function and of all rational functions + + align:start position:0% +function and of all rational functions + + + align:start position:0% +function and of all rational functions +rational functions again are clos + + align:start position:0% +rational functions again are clos + + + align:start position:0% +rational functions again are clos +by other polinomial + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so now the next rule uh that we want to + + align:start position:0% +so now the next rule uh that we want to + + + align:start position:0% +so now the next rule uh that we want to +talk about is the the chain rule + + align:start position:0% + + + + align:start position:0% + +So what is the chain rule? + + align:start position:0% +So what is the chain rule? + + + align:start position:0% +So what is the chain rule? +So the chain rule is a little bit + + align:start position:0% +So the chain rule is a little bit + + + align:start position:0% +So the chain rule is a little bit +different from those three rules here + + align:start position:0% +different from those three rules here + + + align:start position:0% +different from those three rules here +and and it is where you take the + + align:start position:0% +and and it is where you take the + + + align:start position:0% +and and it is where you take the +composition of functions. + + align:start position:0% +composition of functions. + + + align:start position:0% +composition of functions. +So the next is the chain rule + + align:start position:0% + + + + align:start position:0% + +and again this is about + + align:start position:0% +and again this is about + + + align:start position:0% +and again this is about +composition + + align:start position:0% + + + + align:start position:0% + +of functions. + + align:start position:0% + + + + align:start position:0% + +Okay. So I have a function f that goes + + align:start position:0% +Okay. So I have a function f that goes + + + align:start position:0% +Okay. So I have a function f that goes +say from + + align:start position:0% + + + + align:start position:0% + +say that it goes from some interval a to + + align:start position:0% +say that it goes from some interval a to + + + align:start position:0% +say that it goes from some interval a to +b into another interval from c to d + + align:start position:0% +b into another interval from c to d + + + align:start position:0% +b into another interval from c to d +and then I have a function g + + align:start position:0% +and then I have a function g + + + align:start position:0% +and then I have a function g +that goes from this interval here + + align:start position:0% +that goes from this interval here + + + align:start position:0% +that goes from this interval here +into r + + align:start position:0% +into r + + + align:start position:0% +into r +because g is defined you So like + + align:start position:0% +because g is defined you So like + + + align:start position:0% +because g is defined you So like +whatever the the image of of of F always + + align:start position:0% +whatever the the image of of of F always + + + align:start position:0% +whatever the the image of of of F always +if it's in this set this is where G is + + align:start position:0% +if it's in this set this is where G is + + + align:start position:0% +if it's in this set this is where G is +defined then you have that uh you can + + align:start position:0% +defined then you have that uh you can + + + align:start position:0% +defined then you have that uh you can +form + + align:start position:0% +form + + + align:start position:0% +form +if you take some X in here. So if X here + + align:start position:0% +if you take some X in here. So if X here + + + align:start position:0% +if you take some X in here. So if X here +is in A to B then this here makes sense + + align:start position:0% +is in A to B then this here makes sense + + + align:start position:0% +is in A to B then this here makes sense +and this is now an element here. So this + + align:start position:0% +and this is now an element here. So this + + + align:start position:0% +and this is now an element here. So this +is where G is defined. So this here + + align:start position:0% +is where G is defined. So this here + + + align:start position:0% +is where G is defined. So this here +makes sense, right? And this is now what + + align:start position:0% +makes sense, right? And this is now what + + + align:start position:0% +makes sense, right? And this is now what +we call the composition. And we write it + + align:start position:0% +we call the composition. And we write it + + + align:start position:0% +we call the composition. And we write it +like this. It's important to write it in + + align:start position:0% +like this. It's important to write it in + + + align:start position:0% +like this. It's important to write it in +the correct order. + + align:start position:0% +the correct order. + + + align:start position:0% +the correct order. +And so this is the composition function. + + align:start position:0% +And so this is the composition function. + + + align:start position:0% +And so this is the composition function. +Okay. And uh and the thing is that this + + align:start position:0% +Okay. And uh and the thing is that this + + + align:start position:0% +Okay. And uh and the thing is that this +so right. So now the chain rule is the + + align:start position:0% +so right. So now the chain rule is the + + + align:start position:0% +so right. So now the chain rule is the +following. + + align:start position:0% + + + + align:start position:0% + +So the chain rule is a following + + align:start position:0% +So the chain rule is a following + + + align:start position:0% +So the chain rule is a following +theorem. + + align:start position:0% + + + + align:start position:0% + +that if + + align:start position:0% + + + + align:start position:0% + +f is differentiable + + align:start position:0% + + + + align:start position:0% + +at x0 + + align:start position:0% +at x0 + + + align:start position:0% +at x0 +and + + align:start position:0% +and + + + align:start position:0% +and +and uh g + + align:start position:0% +and uh g + + + align:start position:0% +and uh g +is differentiable. + + align:start position:0% + + + + align:start position:0% + +at y0 where y0 is equal to the value of + + align:start position:0% +at y0 where y0 is equal to the value of + + + align:start position:0% +at y0 where y0 is equal to the value of +f at x0. + + align:start position:0% +f at x0. + + + align:start position:0% +f at x0. +Then the composition then the + + align:start position:0% +Then the composition then the + + + align:start position:0% +Then the composition then the +composition of these two functions is + + align:start position:0% +composition of these two functions is + + + align:start position:0% +composition of these two functions is +differentiable + + align:start position:0% +differentiable + + + align:start position:0% +differentiable +at x0. And the derivative is equal to + + align:start position:0% +at x0. And the derivative is equal to + + + align:start position:0% +at x0. And the derivative is equal to +the derivative of g at y0 times the + + align:start position:0% +the derivative of g at y0 times the + + + align:start position:0% +the derivative of g at y0 times the +derivative of f at x0. So this is the + + align:start position:0% +derivative of f at x0. So this is the + + + align:start position:0% +derivative of f at x0. So this is the +chain rule, right? The chain rule say + + align:start position:0% +chain rule, right? The chain rule say + + + align:start position:0% +chain rule, right? The chain rule say +that the composition is also + + align:start position:0% +that the composition is also + + + align:start position:0% +that the composition is also +differentiable + + align:start position:0% +differentiable + + + align:start position:0% +differentiable +at x0. And this is the formula for the + + align:start position:0% +at x0. And this is the formula for the + + + align:start position:0% +at x0. And this is the formula for the +derivative. + + align:start position:0% +derivative. + + + align:start position:0% +derivative. +Okay, let's try to prove that. Uh and so + + align:start position:0% +Okay, let's try to prove that. Uh and so + + + align:start position:0% +Okay, let's try to prove that. Uh and so +that we in this case it's useful to + + align:start position:0% +that we in this case it's useful to + + + align:start position:0% +that we in this case it's useful to +divide up to two to two cases. + + align:start position:0% +divide up to two to two cases. + + + align:start position:0% +divide up to two to two cases. +Um + + align:start position:0% + + + + align:start position:0% + +and the two cases to divide up to. So + + align:start position:0% +and the two cases to divide up to. So + + + align:start position:0% +and the two cases to divide up to. So +let me just look at the look at the + + align:start position:0% +let me just look at the look at the + + + align:start position:0% +let me just look at the look at the +special case first and then once we + + align:start position:0% +special case first and then once we + + + align:start position:0% +special case first and then once we +understand that it's would be clear the + + align:start position:0% +understand that it's would be clear the + + + align:start position:0% +understand that it's would be clear the +general case would be clear. So let's + + align:start position:0% +general case would be clear. So let's + + + align:start position:0% +general case would be clear. So let's +make one assumption. So let's try to + + align:start position:0% +make one assumption. So let's try to + + + align:start position:0% +make one assumption. So let's try to +prove it. + + align:start position:0% + + + + align:start position:0% + +Uh and but we assume first + + align:start position:0% + + + + align:start position:0% + +that the derivative + + align:start position:0% + + + + align:start position:0% + +I'm going to assume that the derivative + + align:start position:0% +I'm going to assume that the derivative + + + align:start position:0% +I'm going to assume that the derivative +at x0 is not equal to zero. So I'm + + align:start position:0% +at x0 is not equal to zero. So I'm + + + align:start position:0% +at x0 is not equal to zero. So I'm +assuming that first. What does this + + align:start position:0% +assuming that first. What does this + + + align:start position:0% +assuming that first. What does this +guarantee me? Well, remember that the + + align:start position:0% +guarantee me? Well, remember that the + + + align:start position:0% +guarantee me? Well, remember that the +derivative is the limit of this + + align:start position:0% +derivative is the limit of this + + + align:start position:0% +derivative is the limit of this +difference quotient, + + align:start position:0% + + + + align:start position:0% + +right? So this is this is the limit. + + align:start position:0% +right? So this is this is the limit. + + + align:start position:0% +right? So this is this is the limit. +If this here is not equal to zero, + + align:start position:0% +If this here is not equal to zero, + + + align:start position:0% +If this here is not equal to zero, +this means that when x is very close to + + align:start position:0% +this means that when x is very close to + + + align:start position:0% +this means that when x is very close to +x0, this thing here + + align:start position:0% +x0, this thing here + + + align:start position:0% +x0, this thing here +is + + align:start position:0% +is + + + align:start position:0% +is +very close to this thing that is not + + align:start position:0% +very close to this thing that is not + + + align:start position:0% +very close to this thing that is not +equal to zero. But then it means that if + + align:start position:0% +equal to zero. But then it means that if + + + align:start position:0% +equal to zero. But then it means that if +you are very close to x0, f ofx cannot + + align:start position:0% +you are very close to x0, f ofx cannot + + + align:start position:0% +you are very close to x0, f ofx cannot +be equal to. So if you have this here, + + align:start position:0% +be equal to. So if you have this here, + + + align:start position:0% +be equal to. So if you have this here, +this implies that f ofx + + align:start position:0% +this implies that f ofx + + + align:start position:0% +this implies that f ofx +is not equal to x0 + + align:start position:0% +is not equal to x0 + + + align:start position:0% +is not equal to x0 +for sorry is not equal to f of x0 + + align:start position:0% +for sorry is not equal to f of x0 + + + align:start position:0% +for sorry is not equal to f of x0 +for + + align:start position:0% +for + + + align:start position:0% +for +x sufficiently closed + + align:start position:0% + + + + align:start position:0% + +close to x0. + + align:start position:0% + + + + align:start position:0% + +I'm always assuming of course that x is + + align:start position:0% +I'm always assuming of course that x is + + + align:start position:0% +I'm always assuming of course that x is +not But x is not equal to right. + + align:start position:0% +not But x is not equal to right. + + + align:start position:0% +not But x is not equal to right. +So, so I'm going to first make this + + align:start position:0% +So, so I'm going to first make this + + + align:start position:0% +So, so I'm going to first make this +assumption. And if I make this + + align:start position:0% +assumption. And if I make this + + + align:start position:0% +assumption. And if I make this +assumption, what I get out of it is that + + align:start position:0% +assumption, what I get out of it is that + + + align:start position:0% +assumption, what I get out of it is that +this thing here is not equal to that. + + align:start position:0% +this thing here is not equal to that. + + + align:start position:0% +this thing here is not equal to that. +Why is this useful? Because now I can + + align:start position:0% +Why is this useful? Because now I can + + + align:start position:0% +Why is this useful? Because now I can +actually look at this difference and I + + align:start position:0% +actually look at this difference and I + + + align:start position:0% +actually look at this difference and I +can divide by it. Okay. + + align:start position:0% +can divide by it. Okay. + + + align:start position:0% +can divide by it. Okay. +So, I'm going to + + align:start position:0% + + + + align:start position:0% + +I'm going to just to make things a + + align:start position:0% +I'm going to just to make things a + + + align:start position:0% +I'm going to just to make things a +little bit clearer. + + align:start position:0% +little bit clearer. + + + align:start position:0% +little bit clearer. +So I have my function. + + align:start position:0% + + + + align:start position:0% + +So this here is is this f and here I + + align:start position:0% +So this here is is this f and here I + + + align:start position:0% +So this here is is this f and here I +have g. + + align:start position:0% +have g. + + + align:start position:0% +have g. +Here I have x0. + + align:start position:0% +Here I have x0. + + + align:start position:0% +Here I have x0. +But under f it's taken to this which is + + align:start position:0% +But under f it's taken to this which is + + + align:start position:0% +But under f it's taken to this which is +f of x0. But this I also will denote by + + align:start position:0% +f of x0. But this I also will denote by + + + align:start position:0% +f of x0. But this I also will denote by +y z right. So I'm denoting just to make + + align:start position:0% +y z right. So I'm denoting just to make + + + align:start position:0% +y z right. So I'm denoting just to make +clear y0 is just the value here. + + align:start position:0% +clear y0 is just the value here. + + + align:start position:0% +clear y0 is just the value here. +And then I will use uh for I will I will + + align:start position:0% +And then I will use uh for I will I will + + + align:start position:0% +And then I will use uh for I will I will +f ofx + + align:start position:0% +f ofx + + + align:start position:0% +f ofx +I will denote by y. Okay. + + align:start position:0% +I will denote by y. Okay. + + + align:start position:0% +I will denote by y. Okay. +So now I'm looking at the difference + + align:start position:0% +So now I'm looking at the difference + + + align:start position:0% +So now I'm looking at the difference +quotient. So I'm looking at f of sorry + + align:start position:0% +quotient. So I'm looking at f of sorry + + + align:start position:0% +quotient. So I'm looking at f of sorry +I'm looking at g of f of x minus uh g of + + align:start position:0% +I'm looking at g of f of x minus uh g of + + + align:start position:0% +I'm looking at g of f of x minus uh g of +f of x0 + + align:start position:0% + + + + align:start position:0% + +uh x - x0 that's what I'm supposed to + + align:start position:0% +uh x - x0 that's what I'm supposed to + + + align:start position:0% +uh x - x0 that's what I'm supposed to +look at + + align:start position:0% +look at + + + align:start position:0% +look at +and I'm can write this thing here + + align:start position:0% +and I'm can write this thing here + + + align:start position:0% +and I'm can write this thing here +as g of y because this here I also call + + align:start position:0% +as g of y because this here I also call + + + align:start position:0% +as g of y because this here I also call +y right so you can write it like this g + + align:start position:0% +y right so you can write it like this g + + + align:start position:0% +y right so you can write it like this g +of y 0 + + align:start position:0% +of y 0 + + + align:start position:0% +of y 0 +and then I will write it as y - y 0 but + + align:start position:0% +and then I will write it as y - y 0 but + + + align:start position:0% +and then I will write it as y - y 0 but +I didn't have this in the denominator up + + align:start position:0% +I didn't have this in the denominator up + + + align:start position:0% +I didn't have this in the denominator up +here so I have to multiply it back on + + align:start position:0% +here so I have to multiply it back on + + + align:start position:0% +here so I have to multiply it back on +and then I still have to divide by like + + align:start position:0% +and then I still have to divide by like + + + align:start position:0% +and then I still have to divide by like +like that right so I can write it like + + align:start position:0% +like that right so I can write it like + + + align:start position:0% +like that right so I can write it like +this this here I'm happy with we'll get + + align:start position:0% +this this here I'm happy with we'll get + + + align:start position:0% +this this here I'm happy with we'll get +to this in just a taken, but I'm happy + + align:start position:0% +to this in just a taken, but I'm happy + + + align:start position:0% +to this in just a taken, but I'm happy +with this expression. The other one I + + align:start position:0% +with this expression. The other one I + + + align:start position:0% +with this expression. The other one I +really want to put it back in in terms + + align:start position:0% +really want to put it back in in terms + + + align:start position:0% +really want to put it back in in terms +of f. So I'm writing this thing here. + + align:start position:0% + + + + align:start position:0% + +And this thing here, I really want to + + align:start position:0% +And this thing here, I really want to + + + align:start position:0% +And this thing here, I really want to +put it back in in terms of f. So if I do + + align:start position:0% +put it back in in terms of f. So if I do + + + align:start position:0% +put it back in in terms of f. So if I do +that, I write it as f ofx - f of x0 + + align:start position:0% +that, I write it as f ofx - f of x0 + + + align:start position:0% +that, I write it as f ofx - f of x0 +x - x0. + + align:start position:0% + + + + align:start position:0% + +But now you see that as um as x go to + + align:start position:0% +But now you see that as um as x go to + + + align:start position:0% +But now you see that as um as x go to +x0, right? + + align:start position:0% +x0, right? + + + align:start position:0% +x0, right? +Well, as x go to x0 the because the + + align:start position:0% +Well, as x go to x0 the because the + + + align:start position:0% +Well, as x go to x0 the because the +function f was continuous at x0 it means + + align:start position:0% +function f was continuous at x0 it means + + + align:start position:0% +function f was continuous at x0 it means +that if x go to x0 then the value at x + + align:start position:0% +that if x go to x0 then the value at x + + + align:start position:0% +that if x go to x0 then the value at x +which is y will go to the value at x0. + + align:start position:0% +which is y will go to the value at x0. + + + align:start position:0% +which is y will go to the value at x0. +So when when + + align:start position:0% +So when when + + + align:start position:0% +So when when +x goes to x0 + + align:start position:0% +x goes to x0 + + + align:start position:0% +x goes to x0 +we have that y goes to y0 + + align:start position:0% + + + + align:start position:0% + +right + + align:start position:0% +right + + + align:start position:0% +right +so this means that this thing here this + + align:start position:0% +so this means that this thing here this + + + align:start position:0% +so this means that this thing here this +here converge right that's just because + + align:start position:0% +here converge right that's just because + + + align:start position:0% +here converge right that's just because +the function f is differentiable so this + + align:start position:0% +the function f is differentiable so this + + + align:start position:0% +the function f is differentiable so this +here will converge to the derivative so + + align:start position:0% +here will converge to the derivative so + + + align:start position:0% +here will converge to the derivative so +this the the second factor here is + + align:start position:0% +this the the second factor here is + + + align:start position:0% +this the the second factor here is +converging to fprime at x0. The first + + align:start position:0% +converging to fprime at x0. The first + + + align:start position:0% +converging to fprime at x0. The first +factor is but now you see that we just + + align:start position:0% +factor is but now you see that we just + + + align:start position:0% +factor is but now you see that we just +argued that y goes to y0. So this is + + align:start position:0% +argued that y goes to y0. So this is + + + align:start position:0% +argued that y goes to y0. So this is +also a difference quotient, but it's a + + align:start position:0% +also a difference quotient, but it's a + + + align:start position:0% +also a difference quotient, but it's a +difference quotient for g. And since y + + align:start position:0% +difference quotient for g. And since y + + + align:start position:0% +difference quotient for g. And since y +goes to y z, this difference quotient + + align:start position:0% +goes to y z, this difference quotient + + + align:start position:0% +goes to y z, this difference quotient +here goes to the derivative of g at at y + + align:start position:0% +here goes to the derivative of g at at y + + + align:start position:0% +here goes to the derivative of g at at y +z. + + align:start position:0% +z. + + + align:start position:0% +z. +Right? But that's exactly the formula + + align:start position:0% +Right? But that's exactly the formula + + + align:start position:0% +Right? But that's exactly the formula +that we wanted to prove except that we + + align:start position:0% +that we wanted to prove except that we + + + align:start position:0% +that we wanted to prove except that we +made one assumption that the derivative + + align:start position:0% +made one assumption that the derivative + + + align:start position:0% +made one assumption that the derivative +of f + + align:start position:0% +of f + + + align:start position:0% +of f +at x0 was not equal to zero. We made + + align:start position:0% +at x0 was not equal to zero. We made + + + align:start position:0% +at x0 was not equal to zero. We made +that assumption only so that this number + + align:start position:0% +that assumption only so that this number + + + align:start position:0% +that assumption only so that this number +here was not equal to zero. Right? And + + align:start position:0% +here was not equal to zero. Right? And + + + align:start position:0% +here was not equal to zero. Right? And +so we could kind of divide by it. + + align:start position:0% +so we could kind of divide by it. + + + align:start position:0% +so we could kind of divide by it. +Right? But actually otherwise + + align:start position:0% +Right? But actually otherwise + + + align:start position:0% +Right? But actually otherwise +um + + align:start position:0% +um + + + align:start position:0% +um +right if if you for some reason if y was + + align:start position:0% +right if if you for some reason if y was + + + align:start position:0% +right if if you for some reason if y was +not equal to y z + + align:start position:0% +not equal to y z + + + align:start position:0% +not equal to y z +but right then this formula here would + + align:start position:0% +but right then this formula here would + + + align:start position:0% +but right then this formula here would +still hold right so it's only the the + + align:start position:0% +still hold right so it's only the the + + + align:start position:0% +still hold right so it's only the the +the possibility + + align:start position:0% +the possibility + + + align:start position:0% +the possibility +that uh that y could be equal to y z but + + align:start position:0% +that uh that y could be equal to y z but + + + align:start position:0% +that uh that y could be equal to y z but +now you see that if you We're just + + align:start position:0% +now you see that if you We're just + + + align:start position:0% +now you see that if you We're just +looking at the difference quotient g of + + align:start position:0% +looking at the difference quotient g of + + + align:start position:0% +looking at the difference quotient g of +f + + align:start position:0% +f + + + align:start position:0% +f +g of uh of y + + align:start position:0% +g of uh of y + + + align:start position:0% +g of uh of y +minus + + align:start position:0% +minus + + + align:start position:0% +minus +sorry uh g of f ofx + + align:start position:0% +sorry uh g of f ofx + + + align:start position:0% +sorry uh g of f ofx +minus. + + align:start position:0% +minus. + + + align:start position:0% +minus. +So this is the difference quotion that + + align:start position:0% +So this is the difference quotion that + + + align:start position:0% +So this is the difference quotion that +is the one we really have to look at for + + align:start position:0% +is the one we really have to look at for + + + align:start position:0% +is the one we really have to look at for +the + + align:start position:0% +the + + + align:start position:0% +the +for the composition right and this is + + align:start position:0% +for the composition right and this is + + + align:start position:0% +for the composition right and this is +what we also called this here is what we + + align:start position:0% +what we also called this here is what we + + + align:start position:0% +what we also called this here is what we +call this thing here is what we called + + align:start position:0% +call this thing here is what we called + + + align:start position:0% +call this thing here is what we called +y0 this thing here is what we call y + + align:start position:0% + + + + align:start position:0% + +and the only case we haven't dealt with + + align:start position:0% +and the only case we haven't dealt with + + + align:start position:0% +and the only case we haven't dealt with +is where f prime + + align:start position:0% +is where f prime + + + align:start position:0% +is where f prime +of zero is equal to zero and + + align:start position:0% +of zero is equal to zero and + + + align:start position:0% +of zero is equal to zero and +y + + align:start position:0% +y + + + align:start position:0% +y +is equal to y z right this here again + + align:start position:0% +is equal to y z right this here again + + + align:start position:0% +is equal to y z right this here again +was f of x and this here was equal to f + + align:start position:0% +was f of x and this here was equal to f + + + align:start position:0% +was f of x and this here was equal to f +of x0 so this only this case here we + + align:start position:0% +of x0 so this only this case here we + + + align:start position:0% +of x0 so this only this case here we +haven't dealt with right + + align:start position:0% +haven't dealt with right + + + align:start position:0% +haven't dealt with right +but you see that if If you if it h if it + + align:start position:0% +but you see that if If you if it h if it + + + align:start position:0% +but you see that if If you if it h if it +so happened that f ofx was equal to f of + + align:start position:0% +so happened that f ofx was equal to f of + + + align:start position:0% +so happened that f ofx was equal to f of +z then this difference quotient here the + + align:start position:0% +z then this difference quotient here the + + + align:start position:0% +z then this difference quotient here the +d the denominator would trivially be + + align:start position:0% +d the denominator would trivially be + + + align:start position:0% +d the denominator would trivially be +zero right and so you want to prove we + + align:start position:0% +zero right and so you want to prove we + + + align:start position:0% +zero right and so you want to prove we +have that if this here was not equal to + + align:start position:0% +have that if this here was not equal to + + + align:start position:0% +have that if this here was not equal to +zero then we have that this is + + align:start position:0% +zero then we have that this is + + + align:start position:0% +zero then we have that this is +converging to the to the derivative + + align:start position:0% +converging to the to the derivative + + + align:start position:0% +converging to the to the derivative +and the only case we have to look at + + align:start position:0% +and the only case we have to look at + + + align:start position:0% +and the only case we have to look at +where this derivative is zero. So we + + align:start position:0% +where this derivative is zero. So we + + + align:start position:0% +where this derivative is zero. So we +want we are claiming that so the only + + align:start position:0% +want we are claiming that so the only + + + align:start position:0% +want we are claiming that so the only +case we're left with that we haven't + + align:start position:0% +case we're left with that we haven't + + + align:start position:0% +case we're left with that we haven't +dealt with is first of all where the + + align:start position:0% +dealt with is first of all where the + + + align:start position:0% +dealt with is first of all where the +derivative + + align:start position:0% +derivative + + + align:start position:0% +derivative +so let's see so + + align:start position:0% + + + + align:start position:0% + +let me just write down here clearly the + + align:start position:0% +let me just write down here clearly the + + + align:start position:0% +let me just write down here clearly the +remaining case + + align:start position:0% + + + + align:start position:0% + +remaining case + + align:start position:0% + + + + align:start position:0% + +for the chain rule + + align:start position:0% + + + + align:start position:0% + +So the main cases that the derivative at + + align:start position:0% +So the main cases that the derivative at + + + align:start position:0% +So the main cases that the derivative at +x0 is zero. Right? + + align:start position:0% + + + + align:start position:0% + +And and we have already observed that if + + align:start position:0% +And and we have already observed that if + + + align:start position:0% +And and we have already observed that if +the derivative is zero but + + align:start position:0% +the derivative is zero but + + + align:start position:0% +the derivative is zero but +but + + align:start position:0% +but + + + align:start position:0% +but +y is not equal to y z. If this is the + + align:start position:0% +y is not equal to y z. If this is the + + + align:start position:0% +y is not equal to y z. If this is the +case then actually g of f ofx + + align:start position:0% +case then actually g of f ofx + + + align:start position:0% +case then actually g of f ofx +minus g + + align:start position:0% +minus g + + + align:start position:0% +minus g +of f of x0. + + align:start position:0% +of f of x0. + + + align:start position:0% +of f of x0. +This thing here + + align:start position:0% +This thing here + + + align:start position:0% +This thing here +still converge in this case here where + + align:start position:0% +still converge in this case here where + + + align:start position:0% +still converge in this case here where +this is the case. This here still + + align:start position:0% +this is the case. This here still + + + align:start position:0% +this is the case. This here still +converts to zero. Right? So, so we still + + align:start position:0% +converts to zero. Right? So, so we still + + + align:start position:0% +converts to zero. Right? So, so we still +have the chain rule + + align:start position:0% +have the chain rule + + + align:start position:0% +have the chain rule +in that case if this here was not the + + align:start position:0% +in that case if this here was not the + + + align:start position:0% +in that case if this here was not the +case. The only thing we have to worry + + align:start position:0% +case. The only thing we have to worry + + + align:start position:0% +case. The only thing we have to worry +about is what if y was equal to y z. But + + align:start position:0% +about is what if y was equal to y z. But + + + align:start position:0% +about is what if y was equal to y z. But +if y was equal to y z when we're looking + + align:start position:0% +if y was equal to y z when we're looking + + + align:start position:0% +if y was equal to y z when we're looking +at the difference quotient, this is the + + align:start position:0% +at the difference quotient, this is the + + + align:start position:0% +at the difference quotient, this is the +difference quotion after all. And so in + + align:start position:0% +difference quotion after all. And so in + + + align:start position:0% +difference quotion after all. And so in +that case, this thing here is y z. This + + align:start position:0% +that case, this thing here is y z. This + + + align:start position:0% +that case, this thing here is y z. This +is y z. But in that case the difference + + align:start position:0% +is y z. But in that case the difference + + + align:start position:0% +is y z. But in that case the difference +quotion is actually zero already. So of + + align:start position:0% +quotion is actually zero already. So of + + + align:start position:0% +quotion is actually zero already. So of +course it's it's going to be very close + + align:start position:0% +course it's it's going to be very close + + + align:start position:0% +course it's it's going to be very close +to zero right it's actually is zero + + align:start position:0% +to zero right it's actually is zero + + + align:start position:0% +to zero right it's actually is zero +right you see that the remaining case + + align:start position:0% +right you see that the remaining case + + + align:start position:0% +right you see that the remaining case +that's sort of trivial + + align:start position:0% +that's sort of trivial + + + align:start position:0% +that's sort of trivial +but we wanted to first exclude it + + align:start position:0% +but we wanted to first exclude it + + + align:start position:0% +but we wanted to first exclude it +because we wanted to be able to divide + + align:start position:0% +because we wanted to be able to divide + + + align:start position:0% +because we wanted to be able to divide +by this difference right and then once + + align:start position:0% +by this difference right and then once + + + align:start position:0% +by this difference right and then once +we have seen that under that assumption + + align:start position:0% +we have seen that under that assumption + + + align:start position:0% +we have seen that under that assumption +it was it was you know we got the + + align:start position:0% +it was it was you know we got the + + + align:start position:0% +it was it was you know we got the +formula we wanted then we go back and + + align:start position:0% +formula we wanted then we go back and + + + align:start position:0% +formula we wanted then we go back and +then we say that not only you know the + + align:start position:0% +then we say that not only you know the + + + align:start position:0% +then we say that not only you know the +the the the the remaining issue was well + + align:start position:0% +the the the the remaining issue was well + + + align:start position:0% +the the the the remaining issue was well +first of all + + align:start position:0% +first of all + + + align:start position:0% +first of all +was the case where the derivative was + + align:start position:0% +was the case where the derivative was + + + align:start position:0% +was the case where the derivative was +zero but in fact um you the only case + + align:start position:0% +zero but in fact um you the only case + + + align:start position:0% +zero but in fact um you the only case +that was potentially a problem was when + + align:start position:0% +that was potentially a problem was when + + + align:start position:0% +that was potentially a problem was when +y was equal to y zero but for that it's + + align:start position:0% +y was equal to y zero but for that it's + + + align:start position:0% +y was equal to y zero but for that it's +the difference quotient was was actually + + align:start position:0% +the difference quotient was was actually + + + align:start position:0% +the difference quotient was was actually +trivial zero okay so that's the the + + align:start position:0% +trivial zero okay so that's the the + + + align:start position:0% +trivial zero okay so that's the the +chain rule + + align:start position:0% + + + + align:start position:0% + +Um, and so we only have a few minutes + + align:start position:0% +Um, and so we only have a few minutes + + + align:start position:0% +Um, and so we only have a few minutes +left. Uh, and I won't quite be able to + + align:start position:0% +left. Uh, and I won't quite be able to + + + align:start position:0% +left. Uh, and I won't quite be able to +get through all of the stuff. Uh, but I + + align:start position:0% +get through all of the stuff. Uh, but I + + + align:start position:0% +get through all of the stuff. Uh, but I +can get through one more lema. + + align:start position:0% +can get through one more lema. + + + align:start position:0% +can get through one more lema. +And so, and then I'll pick up from from + + align:start position:0% +And so, and then I'll pick up from from + + + align:start position:0% +And so, and then I'll pick up from from +here uh, next time. + + align:start position:0% + + + + align:start position:0% + +uh the notes are already posted but but + + align:start position:0% +uh the notes are already posted but but + + + align:start position:0% +uh the notes are already posted but but +so the last bit of the notes we'll do + + align:start position:0% +so the last bit of the notes we'll do + + + align:start position:0% +so the last bit of the notes we'll do +next time. + + align:start position:0% +next time. + + + align:start position:0% +next time. +So so the following lema here. + + align:start position:0% +So so the following lema here. + + + align:start position:0% +So so the following lema here. +So if you have a function + + align:start position:0% +So if you have a function + + + align:start position:0% +So if you have a function +say from R to R + + align:start position:0% +say from R to R + + + align:start position:0% +say from R to R +and you have that X here X0 is a local + + align:start position:0% + + + + align:start position:0% + +max + + align:start position:0% +max + + + align:start position:0% +max +or min. + + align:start position:0% +or min. + + + align:start position:0% +or min. +So f is a function from r to r that is + + align:start position:0% +So f is a function from r to r that is + + + align:start position:0% +So f is a function from r to r that is +that is differentiable. + + align:start position:0% + + + + align:start position:0% + +And uh x0 is a local max or local min + + align:start position:0% + + + + align:start position:0% + +for f. + + align:start position:0% +for f. + + + align:start position:0% +for f. +then uh then + + align:start position:0% +then uh then + + + align:start position:0% +then uh then +the derivative + + align:start position:0% +the derivative + + + align:start position:0% +the derivative +at x0 + + align:start position:0% +at x0 + + + align:start position:0% +at x0 +is equal to zero. Okay, + + align:start position:0% +is equal to zero. Okay, + + + align:start position:0% +is equal to zero. Okay, +let me remind you what a local max and + + align:start position:0% +let me remind you what a local max and + + + align:start position:0% +let me remind you what a local max and +local min is. So if you take a function + + align:start position:0% +local min is. So if you take a function + + + align:start position:0% +local min is. So if you take a function +so a local max similar for a local min + + align:start position:0% +so a local max similar for a local min + + + align:start position:0% +so a local max similar for a local min +if you have a function here you have + + align:start position:0% +if you have a function here you have + + + align:start position:0% +if you have a function here you have +here x0 a local max means that in a + + align:start position:0% +here x0 a local max means that in a + + + align:start position:0% +here x0 a local max means that in a +neighborhood of x this point then the + + align:start position:0% +neighborhood of x this point then the + + + align:start position:0% +neighborhood of x this point then the +value at x0 is the maximum. So local max + + align:start position:0% + + + + align:start position:0% + +at x0 + + align:start position:0% +at x0 + + + align:start position:0% +at x0 +means + + align:start position:0% +means + + + align:start position:0% +means +that they exist + + align:start position:0% + + + + align:start position:0% + +delta greater than zero such that + + align:start position:0% + + + + align:start position:0% + +um that if you're looking at the + + align:start position:0% +um that if you're looking at the + + + align:start position:0% +um that if you're looking at the +interval + + align:start position:0% +interval + + + align:start position:0% +interval +um to either side of x0 this interval + + align:start position:0% +um to either side of x0 this interval + + + align:start position:0% +um to either side of x0 this interval +and you're looking at uh at f here + + align:start position:0% +and you're looking at uh at f here + + + align:start position:0% +and you're looking at uh at f here +restricted to this subset then uh then + + align:start position:0% +restricted to this subset then uh then + + + align:start position:0% +restricted to this subset then uh then +uh x0 is a local max is a max. So this + + align:start position:0% +uh x0 is a local max is a max. So this + + + align:start position:0% +uh x0 is a local max is a max. So this +means that f ofx zero is equal to the + + align:start position:0% +means that f ofx zero is equal to the + + + align:start position:0% +means that f ofx zero is equal to the +max + + align:start position:0% +max + + + align:start position:0% +max +of f where x here is in this little + + align:start position:0% +of f where x here is in this little + + + align:start position:0% +of f where x here is in this little +interval here. + + align:start position:0% + + + + align:start position:0% + +Oops. Like that. + + align:start position:0% +Oops. Like that. + + + align:start position:0% +Oops. Like that. +Right. So it's it may not be right. So, + + align:start position:0% +Right. So it's it may not be right. So, + + + align:start position:0% +Right. So it's it may not be right. So, +so the idea is that it's just the + + align:start position:0% +so the idea is that it's just the + + + align:start position:0% +so the idea is that it's just the +function may look like this and this + + align:start position:0% +function may look like this and this + + + align:start position:0% +function may look like this and this +here is x0. So, you see that in a + + align:start position:0% +here is x0. So, you see that in a + + + align:start position:0% +here is x0. So, you see that in a +neighborhood like this, it looks like + + align:start position:0% +neighborhood like this, it looks like + + + align:start position:0% +neighborhood like this, it looks like +that you have that this x0 is a maximum, + + align:start position:0% +that you have that this x0 is a maximum, + + + align:start position:0% +that you have that this x0 is a maximum, +but there might even be somewhere else + + align:start position:0% +but there might even be somewhere else + + + align:start position:0% +but there might even be somewhere else +where the value is much higher. Right? + + align:start position:0% +where the value is much higher. Right? + + + align:start position:0% +where the value is much higher. Right? +So, that's a local maximum and similarly + + align:start position:0% +So, that's a local maximum and similarly + + + align:start position:0% +So, that's a local maximum and similarly +for a local minimum. Okay? And so I + + align:start position:0% +for a local minimum. Okay? And so I + + + align:start position:0% +for a local minimum. Okay? And so I +won't be able to to actually prove this + + align:start position:0% +won't be able to to actually prove this + + + align:start position:0% +won't be able to to actually prove this +lema. We we'll prove that next time. Uh + + align:start position:0% +lema. We we'll prove that next time. Uh + + + align:start position:0% +lema. We we'll prove that next time. Uh +and then once we have that lema, we + + align:start position:0% +and then once we have that lema, we + + + align:start position:0% +and then once we have that lema, we +prove what's called roles theorem. And + + align:start position:0% +prove what's called roles theorem. And + + + align:start position:0% +prove what's called roles theorem. And +then we will use it to prove the mean + + align:start position:0% +then we will use it to prove the mean + + + align:start position:0% +then we will use it to prove the mean +battle theorem. But so but I'll do that + + align:start position:0% +battle theorem. But so but I'll do that + + + align:start position:0% +battle theorem. But so but I'll do that +next time, but it's actually in the + + align:start position:0% +next time, but it's actually in the + + + align:start position:0% +next time, but it's actually in the +notes that I I posted already. \ No newline at end of file diff --git a/UZQGn1L2CzQ.txt b/UZQGn1L2CzQ.txt new file mode 100644 index 0000000000000000000000000000000000000000..262fb93f31925dd5238ae33407d49e35b2efcdfe --- /dev/null +++ b/UZQGn1L2CzQ.txt @@ -0,0 +1,1795 @@ +align:start position:0% + +hi everyone I'm Lan welcome back to + + align:start position:0% +hi everyone I'm Lan welcome back to + + + align:start position:0% +hi everyone I'm Lan welcome back to +recitation in recent lectures we have + + align:start position:0% +recitation in recent lectures we have + + + align:start position:0% +recitation in recent lectures we have +studied the properties of the + + align:start position:0% +studied the properties of the + + + align:start position:0% +studied the properties of the +determinant and we also derived the + + align:start position:0% +determinant and we also derived the + + + align:start position:0% +determinant and we also derived the +formula to computed today we're going to + + align:start position:0% +formula to computed today we're going to + + + align:start position:0% +formula to computed today we're going to +put what we learned into practice by + + align:start position:0% +put what we learned into practice by + + + align:start position:0% +put what we learned into practice by +considering these two + + align:start position:0% +considering these two + + + align:start position:0% +considering these two +examples so we want to find out the + + align:start position:0% +examples so we want to find out the + + + align:start position:0% +examples so we want to find out the +determinants of these two 5x five + + align:start position:0% +determinants of these two 5x five + + + align:start position:0% +determinants of these two 5x five +matrices and and as you can see Matrix a + + align:start position:0% +matrices and and as you can see Matrix a + + + align:start position:0% +matrices and and as you can see Matrix a +has X along this diagonal and in the + + align:start position:0% +has X along this diagonal and in the + + + align:start position:0% +has X along this diagonal and in the +first four rows y to the right of X + + align:start position:0% +first four rows y to the right of X + + + align:start position:0% +first four rows y to the right of X +except for the last row and zero entries + + align:start position:0% +except for the last row and zero entries + + + align:start position:0% +except for the last row and zero entries +everywhere else and Matrix B also has X + + align:start position:0% +everywhere else and Matrix B also has X + + + align:start position:0% +everywhere else and Matrix B also has X +along this diagonal and Y everywhere + + align:start position:0% +along this diagonal and Y everywhere + + + align:start position:0% +along this diagonal and Y everywhere +else okay before starting let me help + + align:start position:0% +else okay before starting let me help + + + align:start position:0% +else okay before starting let me help +you review what you can do to compute + + align:start position:0% +you review what you can do to compute + + + align:start position:0% +you review what you can do to compute +determinants of course you can carry out + + align:start position:0% +determinants of course you can carry out + + + align:start position:0% +determinants of course you can carry out +elimination to transform your original + + align:start position:0% +elimination to transform your original + + + align:start position:0% +elimination to transform your original +Matrix into upper triangular + + align:start position:0% +Matrix into upper triangular + + + align:start position:0% +Matrix into upper triangular +Matrix or you can use this big summation + + align:start position:0% +Matrix or you can use this big summation + + + align:start position:0% +Matrix or you can use this big summation +formula another choice would be you can + + align:start position:0% +formula another choice would be you can + + + align:start position:0% +formula another choice would be you can +do it by co-actors namely you can expand + + align:start position:0% +do it by co-actors namely you can expand + + + align:start position:0% +do it by co-actors namely you can expand +your original Matrix along any row or + + align:start position:0% +your original Matrix along any row or + + + align:start position:0% +your original Matrix along any row or +any column and then the determinant is + + align:start position:0% +any column and then the determinant is + + + align:start position:0% +any column and then the determinant is +simply given by the dotproduct of that + + align:start position:0% +simply given by the dotproduct of that + + + align:start position:0% +simply given by the dotproduct of that +row or that column with its + + align:start position:0% +row or that column with its + + + align:start position:0% +row or that column with its +co-actors okay why don't you pause the + + align:start position:0% +co-actors okay why don't you pause the + + + align:start position:0% +co-actors okay why don't you pause the +video now and try to work on them + + align:start position:0% +video now and try to work on them + + + align:start position:0% +video now and try to work on them +yourself whenever you're ready I'll come + + align:start position:0% +yourself whenever you're ready I'll come + + + align:start position:0% +yourself whenever you're ready I'll come +back and show you my + + align:start position:0% + + + + align:start position:0% + +way okay I hope you just had some fun + + align:start position:0% +way okay I hope you just had some fun + + + align:start position:0% +way okay I hope you just had some fun +with these two problems now let's tackle + + align:start position:0% +with these two problems now let's tackle + + + align:start position:0% +with these two problems now let's tackle +them together um let's look at Matrix a + + align:start position:0% +them together um let's look at Matrix a + + + align:start position:0% +them together um let's look at Matrix a +first as you can see there are a lot of + + align:start position:0% +first as you can see there are a lot of + + + align:start position:0% +first as you can see there are a lot of +zero entries in Matrix a so perhaps per + + align:start position:0% +zero entries in Matrix a so perhaps per + + + align:start position:0% +zero entries in Matrix a so perhaps per +you don't need elimination to introduce + + align:start position:0% +you don't need elimination to introduce + + + align:start position:0% +you don't need elimination to introduce +more + + align:start position:0% +more + + + align:start position:0% +more +zeros um furthermore we observe this + + align:start position:0% +zeros um furthermore we observe this + + + align:start position:0% +zeros um furthermore we observe this +pattern of a and you notice that if I + + align:start position:0% +pattern of a and you notice that if I + + + align:start position:0% +pattern of a and you notice that if I +cover the last row and the First Column + + align:start position:0% +cover the last row and the First Column + + + align:start position:0% +cover the last row and the First Column +so if this column and this row not here + + align:start position:0% +so if this column and this row not here + + + align:start position:0% +so if this column and this row not here +what is left over is simply a 4x4 lower + + align:start position:0% +what is left over is simply a 4x4 lower + + + align:start position:0% +what is left over is simply a 4x4 lower +triangular + + align:start position:0% +triangular + + + align:start position:0% +triangular +Matrix and similarly if you cover the + + align:start position:0% +Matrix and similarly if you cover the + + + align:start position:0% +Matrix and similarly if you cover the +First Column and the first row + + align:start position:0% +First Column and the first row + + + align:start position:0% +First Column and the first row +what is left over here is simply a 4x4 + + align:start position:0% +what is left over here is simply a 4x4 + + + align:start position:0% +what is left over here is simply a 4x4 +upper triangular + + align:start position:0% +upper triangular + + + align:start position:0% +upper triangular +Matrix this is telling us that we should + + align:start position:0% +Matrix this is telling us that we should + + + align:start position:0% +Matrix this is telling us that we should +calculate the determinant of a by the + + align:start position:0% +calculate the determinant of a by the + + + align:start position:0% +calculate the determinant of a by the +third method so we should expand along + + align:start position:0% +third method so we should expand along + + + align:start position:0% +third method so we should expand along +the First Column of a and we calculate + + align:start position:0% +the First Column of a and we calculate + + + align:start position:0% +the First Column of a and we calculate +the co-actors let's do it + + align:start position:0% +the co-actors let's do it + + + align:start position:0% +the co-actors let's do it +now + + align:start position:0% +now + + + align:start position:0% +now +so determinant of + + align:start position:0% + + + + align:start position:0% + +a is equal to the one one entry of a + + align:start position:0% +a is equal to the one one entry of a + + + align:start position:0% +a is equal to the one one entry of a +which is + + align:start position:0% +which is + + + align:start position:0% +which is +x times the co-actor of that spot which + + align:start position:0% +x times the co-actor of that spot which + + + align:start position:0% +x times the co-actor of that spot which +is the determinant of the left over 4x4 + + align:start position:0% +is the determinant of the left over 4x4 + + + align:start position:0% +is the determinant of the left over 4x4 +Matrix Matrix and it's upper triangular + + align:start position:0% +Matrix Matrix and it's upper triangular + + + align:start position:0% +Matrix Matrix and it's upper triangular +so it's determinant is simply given by X + + align:start position:0% +so it's determinant is simply given by X + + + align:start position:0% +so it's determinant is simply given by X +to the^ + + align:start position:0% +to the^ + + + align:start position:0% +to the^ +4 right plus the only other non Zero + + align:start position:0% +4 right plus the only other non Zero + + + align:start position:0% +4 right plus the only other non Zero +Entry in that column is the Y at the + + align:start position:0% +Entry in that column is the Y at the + + + align:start position:0% +Entry in that column is the Y at the +very bottom so you put y + + align:start position:0% +very bottom so you put y + + + align:start position:0% +very bottom so you put y +here and you multiply y by the co-actor + + align:start position:0% +here and you multiply y by the co-actor + + + align:start position:0% +here and you multiply y by the co-actor +of that spot which is a determinant of + + align:start position:0% +of that spot which is a determinant of + + + align:start position:0% +of that spot which is a determinant of +the left left over 4x4 Matrix again in + + align:start position:0% +the left left over 4x4 Matrix again in + + + align:start position:0% +the left left over 4x4 Matrix again in +this case it's lower triangular and it's + + align:start position:0% +this case it's lower triangular and it's + + + align:start position:0% +this case it's lower triangular and it's +determinant is y to the^ 4 so I have a y + + align:start position:0% +determinant is y to the^ 4 so I have a y + + + align:start position:0% +determinant is y to the^ 4 so I have a y +to the^ 4 here but not quite in + + align:start position:0% +to the^ 4 here but not quite in + + + align:start position:0% +to the^ 4 here but not quite in +principle there should be another Factor + + align:start position:0% +principle there should be another Factor + + + align:start position:0% +principle there should be another Factor +here indicating the sign and the sign + + align:start position:0% +here indicating the sign and the sign + + + align:start position:0% +here indicating the sign and the sign +in this case well because Y is the the + + align:start position:0% +in this case well because Y is the the + + + align:start position:0% +in this case well because Y is the the +entry in the fifth row in the First + + align:start position:0% +entry in the fifth row in the First + + + align:start position:0% +entry in the fifth row in the First +Column so this Factor should be -1 to + + align:start position:0% +Column so this Factor should be -1 to + + + align:start position:0% +Column so this Factor should be -1 to +the power 5 + 1 and of course it's just + + align:start position:0% +the power 5 + 1 and of course it's just + + + align:start position:0% +the power 5 + 1 and of course it's just +one so the determinant of a is simply + + align:start position:0% +one so the determinant of a is simply + + + align:start position:0% +one so the determinant of a is simply +equal to x to the 5ifth power plus y to + + align:start position:0% +equal to x to the 5ifth power plus y to + + + align:start position:0% +equal to x to the 5ifth power plus y to +the fifth power did you get the correct + + align:start position:0% +the fifth power did you get the correct + + + align:start position:0% +the fifth power did you get the correct +answer well the determinant of a is not + + align:start position:0% +answer well the determinant of a is not + + + align:start position:0% +answer well the determinant of a is not +too bad because a has a lot of zero + + align:start position:0% +too bad because a has a lot of zero + + + align:start position:0% +too bad because a has a lot of zero +entries now let's look at the + + align:start position:0% +entries now let's look at the + + + align:start position:0% +entries now let's look at the +determinant of Matrix B I have another + + align:start position:0% +determinant of Matrix B I have another + + + align:start position:0% +determinant of Matrix B I have another +copy of B here so B also has a very + + align:start position:0% +copy of B here so B also has a very + + + align:start position:0% +copy of B here so B also has a very +clear structure it has X along this + + align:start position:0% +clear structure it has X along this + + + align:start position:0% +clear structure it has X along this +diagonal and Y everywhere else but in + + align:start position:0% +diagonal and Y everywhere else but in + + + align:start position:0% +diagonal and Y everywhere else but in +general b does not have any Zero Entry + + align:start position:0% +general b does not have any Zero Entry + + + align:start position:0% +general b does not have any Zero Entry +so perhaps our first step should be + + align:start position:0% +so perhaps our first step should be + + + align:start position:0% +so perhaps our first step should be +carrying out elimination to introduce + + align:start position:0% +carrying out elimination to introduce + + + align:start position:0% +carrying out elimination to introduce +zero entries into Matrix + + align:start position:0% +zero entries into Matrix + + + align:start position:0% +zero entries into Matrix +B of course you can do it by the regular + + align:start position:0% +B of course you can do it by the regular + + + align:start position:0% +B of course you can do it by the regular +routine you start with the first row + + align:start position:0% +routine you start with the first row + + + align:start position:0% +routine you start with the first row +find the pivot and you eliminate the + + align:start position:0% +find the pivot and you eliminate the + + + align:start position:0% +find the pivot and you eliminate the +second row and the third row and so on + + align:start position:0% +second row and the third row and so on + + + align:start position:0% +second row and the third row and so on +so forth but in this case there's a + + align:start position:0% +so forth but in this case there's a + + + align:start position:0% +so forth but in this case there's a +shortcut if you compare two rows that + + align:start position:0% +shortcut if you compare two rows that + + + align:start position:0% +shortcut if you compare two rows that +are next to each other for example if + + align:start position:0% +are next to each other for example if + + + align:start position:0% +are next to each other for example if +you compare the fourth row and the fifth + + align:start position:0% +you compare the fourth row and the fifth + + + align:start position:0% +you compare the fourth row and the fifth +row you notice that they have a lot of + + align:start position:0% +row you notice that they have a lot of + + + align:start position:0% +row you notice that they have a lot of +entries in common and they're only + + align:start position:0% +entries in common and they're only + + + align:start position:0% +entries in common and they're only +different at these two spots right so + + align:start position:0% +different at these two spots right so + + + align:start position:0% +different at these two spots right so +imagine if I subtract the fourth row + + align:start position:0% +imagine if I subtract the fourth row + + + align:start position:0% +imagine if I subtract the fourth row +from the fifth row so if I do the + + align:start position:0% +from the fifth row so if I do the + + + align:start position:0% +from the fifth row so if I do the +following corporate uh + + align:start position:0% +following corporate uh + + + align:start position:0% +following corporate uh +operation so I + + align:start position:0% +operation so I + + + align:start position:0% +operation so I +subtract this this Row from the last row + + align:start position:0% +subtract this this Row from the last row + + + align:start position:0% +subtract this this Row from the last row +then the new fifth row should become the + + align:start position:0% +then the new fifth row should become the + + + align:start position:0% +then the new fifth row should become the +following + + align:start position:0% +following + + + align:start position:0% +following +so this rule will become 0 0 0 y - + + align:start position:0% +so this rule will become 0 0 0 y - + + + align:start position:0% +so this rule will become 0 0 0 y - +x X - + + align:start position:0% + + + + align:start position:0% + +y you see just by this simple operation + + align:start position:0% +y you see just by this simple operation + + + align:start position:0% +y you see just by this simple operation +I have introduced three zero entries at + + align:start position:0% + + + + align:start position:0% + +once and it's similar with the fourth + + align:start position:0% +once and it's similar with the fourth + + + align:start position:0% +once and it's similar with the fourth +row and the third row they have common + + align:start position:0% +row and the third row they have common + + + align:start position:0% +row and the third row they have common +entries here here and here so you + + align:start position:0% +entries here here and here so you + + + align:start position:0% +entries here here and here so you +subtract the third row from the fourth + + align:start position:0% + + + + align:start position:0% + +row you update the fourth row to 0 0 y - + + align:start position:0% +row you update the fourth row to 0 0 y - + + + align:start position:0% +row you update the fourth row to 0 0 y - +x X - y 0 again three zero entries and + + align:start position:0% +x X - y 0 again three zero entries and + + + align:start position:0% +x X - y 0 again three zero entries and +same thing happened to the third second + + align:start position:0% +same thing happened to the third second + + + align:start position:0% +same thing happened to the third second +row and the third row so you subtract + + align:start position:0% +row and the third row so you subtract + + + align:start position:0% +row and the third row so you subtract +the second row from the third row and + + align:start position:0% +the second row from the third row and + + + align:start position:0% +the second row from the third row and +you your new third row will become + + align:start position:0% +you your new third row will become + + + align:start position:0% +you your new third row will become +0 y - x X - y 0 + + align:start position:0% +0 y - x X - y 0 + + + align:start position:0% +0 y - x X - y 0 +0 finally you subtract the first row + + align:start position:0% +0 finally you subtract the first row + + + align:start position:0% +0 finally you subtract the first row +from the second + + align:start position:0% + + + + align:start position:0% + +row and then you update the second row + + align:start position:0% +row and then you update the second row + + + align:start position:0% +row and then you update the second row +to y - + + align:start position:0% +to y - + + + align:start position:0% +to y - +x X - y 0 0 zero let's keep the first + + align:start position:0% +x X - y 0 0 zero let's keep the first + + + align:start position:0% +x X - y 0 0 zero let's keep the first +row unchanged so I'm going to copy it + + align:start position:0% +row unchanged so I'm going to copy it + + + align:start position:0% +row unchanged so I'm going to copy it +here + + align:start position:0% + + + + align:start position:0% + +all right by row elimination we have + + align:start position:0% +all right by row elimination we have + + + align:start position:0% +all right by row elimination we have +introduced many zero entries to Matrix B + + align:start position:0% +introduced many zero entries to Matrix B + + + align:start position:0% +introduced many zero entries to Matrix B +is there anything else that I can take + + align:start position:0% +is there anything else that I can take + + + align:start position:0% +is there anything else that I can take +advantage + + align:start position:0% +advantage + + + align:start position:0% +advantage +of um let's observe the pattern of this + + align:start position:0% +of um let's observe the pattern of this + + + align:start position:0% +of um let's observe the pattern of this +new Matrix as you can see in each row + + align:start position:0% +new Matrix as you can see in each row + + + align:start position:0% +new Matrix as you can see in each row +you have two nonzero entries except the + + align:start position:0% +you have two nonzero entries except the + + + align:start position:0% +you have two nonzero entries except the +first row and they're only different by + + align:start position:0% +first row and they're only different by + + + align:start position:0% +first row and they're only different by +a sign so if somehow you can figure out + + align:start position:0% +a sign so if somehow you can figure out + + + align:start position:0% +a sign so if somehow you can figure out +a way to sum them up you will get even + + align:start position:0% +a way to sum them up you will get even + + + align:start position:0% +a way to sum them up you will get even +more zero entries so let's do it that's + + align:start position:0% +more zero entries so let's do it that's + + + align:start position:0% +more zero entries so let's do it that's +going to involve the operations on + + align:start position:0% +going to involve the operations on + + + align:start position:0% +going to involve the operations on +column so here is how I do + + align:start position:0% + + + + align:start position:0% + +it I'm going to keep the last column + + align:start position:0% +it I'm going to keep the last column + + + align:start position:0% +it I'm going to keep the last column +unchanged so the last column is y 0 0 0 + + align:start position:0% +unchanged so the last column is y 0 0 0 + + + align:start position:0% +unchanged so the last column is y 0 0 0 +x - y + + align:start position:0% + + + + align:start position:0% + +what I will do is I will add a copy of + + align:start position:0% +what I will do is I will add a copy of + + + align:start position:0% +what I will do is I will add a copy of +the last column to the fourth column so + + align:start position:0% +the last column to the fourth column so + + + align:start position:0% +the last column to the fourth column so +this is what I'm going to do add one + + align:start position:0% +this is what I'm going to do add one + + + align:start position:0% +this is what I'm going to do add one +copy of the last + + align:start position:0% +copy of the last + + + align:start position:0% +copy of the last +column to the fourth column now the new + + align:start position:0% +column to the fourth column now the new + + + align:start position:0% +column to the fourth column now the new +fourth column will become 2 + + align:start position:0% +fourth column will become 2 + + + align:start position:0% +fourth column will become 2 +y 0 0 x - y + + align:start position:0% +y 0 0 x - y + + + align:start position:0% +y 0 0 x - y +z as you can see by doing this + + align:start position:0% +z as you can see by doing this + + + align:start position:0% +z as you can see by doing this +I have killed the spot so I have + + align:start position:0% +I have killed the spot so I have + + + align:start position:0% +I have killed the spot so I have +introduced one more Zero Entry into my + + align:start position:0% +introduced one more Zero Entry into my + + + align:start position:0% +introduced one more Zero Entry into my +fourth + + align:start position:0% +fourth + + + align:start position:0% +fourth +column if you continue you may want to + + align:start position:0% +column if you continue you may want to + + + align:start position:0% +column if you continue you may want to +add the fourth column to the third + + align:start position:0% +add the fourth column to the third + + + align:start position:0% +add the fourth column to the third +column let's see what will happen if you + + align:start position:0% +column let's see what will happen if you + + + align:start position:0% +column let's see what will happen if you +do that so if you add the fourth + + align:start position:0% +do that so if you add the fourth + + + align:start position:0% +do that so if you add the fourth +column to the third + + align:start position:0% +column to the third + + + align:start position:0% +column to the third +column then what should appear here is 2 + + align:start position:0% +column then what should appear here is 2 + + + align:start position:0% +column then what should appear here is 2 +y + + align:start position:0% +y + + + align:start position:0% +y +0 x - y 0 y - + + align:start position:0% + + + + align:start position:0% + +x okay but in this new third column you + + align:start position:0% +x okay but in this new third column you + + + align:start position:0% +x okay but in this new third column you +still have two zero entries which is the + + align:start position:0% +still have two zero entries which is the + + + align:start position:0% +still have two zero entries which is the +same as the original third column so + + align:start position:0% +same as the original third column so + + + align:start position:0% +same as the original third column so +although you've killed this spot but + + align:start position:0% +although you've killed this spot but + + + align:start position:0% +although you've killed this spot but +you've introduced a new nonzero entry so + + align:start position:0% +you've introduced a new nonzero entry so + + + align:start position:0% +you've introduced a new nonzero entry so +is there a way that we can kill the spot + + align:start position:0% +is there a way that we can kill the spot + + + align:start position:0% +is there a way that we can kill the spot +too + + align:start position:0% +too + + + align:start position:0% +too +you may have noticed that if you add a + + align:start position:0% +you may have noticed that if you add a + + + align:start position:0% +you may have noticed that if you add a +copy of the fifth column to this column + + align:start position:0% +copy of the fifth column to this column + + + align:start position:0% +copy of the fifth column to this column +again then this spot will have been + + align:start position:0% +again then this spot will have been + + + align:start position:0% +again then this spot will have been +killed right so let's do it if I add + + align:start position:0% +killed right so let's do it if I add + + + align:start position:0% +killed right so let's do it if I add +this column to this one I'm going to + + align:start position:0% +this column to this one I'm going to + + + align:start position:0% +this column to this one I'm going to +just update it here then the first entry + + align:start position:0% +just update it here then the first entry + + + align:start position:0% +just update it here then the first entry +should + + align:start position:0% +should + + + align:start position:0% +should +become 3 + + align:start position:0% +become 3 + + + align:start position:0% +become 3 +y these are + + align:start position:0% +y these are + + + align:start position:0% +y these are +unchanged and the last spot becomes zero + + align:start position:0% + + + + align:start position:0% + +it reflects here as you are adding a + + align:start position:0% +it reflects here as you are adding a + + + align:start position:0% +it reflects here as you are adding a +copy of the fourth column and a copy of + + align:start position:0% +copy of the fourth column and a copy of + + + align:start position:0% +copy of the fourth column and a copy of +the fifth column to the third + + align:start position:0% +the fifth column to the third + + + align:start position:0% +the fifth column to the third +column now you've got the idea and you + + align:start position:0% +column now you've got the idea and you + + + align:start position:0% +column now you've got the idea and you +continue what do you do with the second + + align:start position:0% +continue what do you do with the second + + + align:start position:0% +continue what do you do with the second +column this time you will have to + + align:start position:0% +column this time you will have to + + + align:start position:0% +column this time you will have to +add a copy of the third column a copy of + + align:start position:0% +add a copy of the third column a copy of + + + align:start position:0% +add a copy of the third column a copy of +the fifth fourth column and the copy of + + align:start position:0% +the fifth fourth column and the copy of + + + align:start position:0% +the fifth fourth column and the copy of +the fifth + + align:start position:0% + + + + align:start position:0% + +column so you update the second column + + align:start position:0% +column so you update the second column + + + align:start position:0% +column so you update the second column +to be 4 + + align:start position:0% +to be 4 + + + align:start position:0% +to be 4 +y x - + + align:start position:0% +y x - + + + align:start position:0% +y x - +y0 z + + align:start position:0% + + + + align:start position:0% + +z eventually what you will do to the + + align:start position:0% +z eventually what you will do to the + + + align:start position:0% +z eventually what you will do to the +First Column would be you add everything + + align:start position:0% +First Column would be you add everything + + + align:start position:0% +First Column would be you add everything +to the four the first column + + align:start position:0% +to the four the first column + + + align:start position:0% +to the four the first column +so a copy of + + align:start position:0% + + + + align:start position:0% + +each then the First Column will become + + align:start position:0% +each then the First Column will become + + + align:start position:0% +each then the First Column will become +so I don't have enough spot here so make + + align:start position:0% +so I don't have enough spot here so make + + + align:start position:0% +so I don't have enough spot here so make +it here x + 4 + + align:start position:0% +it here x + 4 + + + align:start position:0% +it here x + 4 +y then everything + + align:start position:0% +y then everything + + + align:start position:0% +y then everything +else is + + align:start position:0% +else is + + + align:start position:0% +else is +zero this is fun and the result is + + align:start position:0% +zero this is fun and the result is + + + align:start position:0% +zero this is fun and the result is +really nice this is is wonderful because + + align:start position:0% +really nice this is is wonderful because + + + align:start position:0% +really nice this is is wonderful because +this is simply our triangular Matrix now + + align:start position:0% +this is simply our triangular Matrix now + + + align:start position:0% +this is simply our triangular Matrix now +you tell me what is the determinant of B + + align:start position:0% +you tell me what is the determinant of B + + + align:start position:0% +you tell me what is the determinant of B +the determinant of + + align:start position:0% +the determinant of + + + align:start position:0% +the determinant of +B is the + + align:start position:0% +B is the + + + align:start position:0% +B is the +determinant of this upper triangular + + align:start position:0% +determinant of this upper triangular + + + align:start position:0% +determinant of this upper triangular +Matrix so you simply multiply everything + + align:start position:0% +Matrix so you simply multiply everything + + + align:start position:0% +Matrix so you simply multiply everything +together that's x + 4 + + align:start position:0% +together that's x + 4 + + + align:start position:0% +together that's x + 4 +y time x - + + align:start position:0% +y time x - + + + align:start position:0% +y time x - +y to the fourth + + align:start position:0% +y to the fourth + + + align:start position:0% +y to the fourth +power okay + + align:start position:0% +power okay + + + align:start position:0% +power okay +so I hope you enjoy these two + + align:start position:0% +so I hope you enjoy these two + + + align:start position:0% +so I hope you enjoy these two +examples maybe your method is different + + align:start position:0% +examples maybe your method is different + + + align:start position:0% +examples maybe your method is different +from mine but at least these two + + align:start position:0% +from mine but at least these two + + + align:start position:0% +from mine but at least these two +examples teach us that you can be + + align:start position:0% +examples teach us that you can be + + + align:start position:0% +examples teach us that you can be +flexible in combining methods in + + align:start position:0% +flexible in combining methods in + + + align:start position:0% +flexible in combining methods in +calculating determinants thanks for + + align:start position:0% +calculating determinants thanks for + + + align:start position:0% +calculating determinants thanks for +watching and I'm looking forward to see + + align:start position:0% +watching and I'm looking forward to see + + + align:start position:0% +watching and I'm looking forward to see +you soon \ No newline at end of file diff --git a/UzDqh-1Koyc.txt b/UzDqh-1Koyc.txt new file mode 100644 index 0000000000000000000000000000000000000000..00785164fbb34d14b980638817f012a348c178c8 --- /dev/null +++ b/UzDqh-1Koyc.txt @@ -0,0 +1,8171 @@ +align:start position:0% + +but um back to Mo Theory which is where + + align:start position:0% +but um back to Mo Theory which is where + + + align:start position:0% +but um back to Mo Theory which is where +what we talked about uh last Friday and + + align:start position:0% +what we talked about uh last Friday and + + + align:start position:0% +what we talked about uh last Friday and +and there were sort of two last things I + + align:start position:0% +and there were sort of two last things I + + + align:start position:0% +and there were sort of two last things I +wanted to to mention now uh related to + + align:start position:0% +wanted to to mention now uh related to + + + align:start position:0% +wanted to to mention now uh related to +ml Theory before moving on to the topic + + align:start position:0% +ml Theory before moving on to the topic + + + align:start position:0% +ml Theory before moving on to the topic +of + + align:start position:0% +of + + + align:start position:0% +of +hybridization um um now before I do that + + align:start position:0% +hybridization um um now before I do that + + + align:start position:0% +hybridization um um now before I do that +you know I'm going to use a couple of + + align:start position:0% +you know I'm going to use a couple of + + + align:start position:0% +you know I'm going to use a couple of +videos today and I'm I'm not going to + + align:start position:0% +videos today and I'm I'm not going to + + + align:start position:0% +videos today and I'm I'm not going to +show you this one but I just want to + + align:start position:0% +show you this one but I just want to + + + align:start position:0% +show you this one but I just want to +mention there's lots of videos that help + + align:start position:0% +mention there's lots of videos that help + + + align:start position:0% +mention there's lots of videos that help +you know animate this stuff right so + + align:start position:0% +you know animate this stuff right so + + + align:start position:0% +you know animate this stuff right so +like this is what you know so + + align:start position:0% + + + + align:start position:0% + +like bonding molecular + + align:start position:0% +like bonding molecular + + + align:start position:0% +like bonding molecular +orbital combination of two an anti + + align:start position:0% +orbital combination of two an anti + + + align:start position:0% +orbital combination of two an anti +antibonding we talk about this last + + align:start position:0% +antibonding we talk about this last + + + align:start position:0% +antibonding we talk about this last +Friday but look at this + + align:start position:0% +Friday but look at this + + + align:start position:0% +Friday but look at this +animation I couldn't do that on the + + align:start position:0% +animation I couldn't do that on the + + + align:start position:0% +animation I couldn't do that on the +board watch this molecular orbitals + + align:start position:0% +board watch this molecular orbitals + + + align:start position:0% +board watch this molecular orbitals +formed by the combination of two 1s + + align:start position:0% +formed by the combination of two 1s + + + align:start position:0% +formed by the combination of two 1s +orbitals are called Sigma + + align:start position:0% +orbitals are called Sigma + + + align:start position:0% +orbitals are called Sigma +1s and Sig star + + align:start position:0% +1s and Sig star + + + align:start position:0% +1s and Sig star +1s kind of remembering stuff now right + + align:start position:0% +1s kind of remembering stuff now right + + + align:start position:0% +1s kind of remembering stuff now right +from + + align:start position:0% +from + + + align:start position:0% +from +Friday oh look at + + align:start position:0% +Friday oh look at + + + align:start position:0% +Friday oh look at +that + + align:start position:0% +that + + + align:start position:0% +that +original that's that kind of Animation + + align:start position:0% +original that's that kind of Animation + + + align:start position:0% +original that's that kind of Animation +that you just can't you know I can't + + align:start position:0% +that you just can't you know I can't + + + align:start position:0% +that you just can't you know I can't +animate the bonding and antibonding well + + align:start position:0% +animate the bonding and antibonding well + + + align:start position:0% +animate the bonding and antibonding well +I kind of can with my hands but but + + align:start position:0% +I kind of can with my hands but but + + + align:start position:0% +I kind of can with my hands but but +there it is and there's lots and lots of + + align:start position:0% +there it is and there's lots and lots of + + + align:start position:0% +there it is and there's lots and lots of +those kinds of videos I'll show you a + + align:start position:0% +those kinds of videos I'll show you a + + + align:start position:0% +those kinds of videos I'll show you a +couple today related to hybridization + + align:start position:0% +couple today related to hybridization + + + align:start position:0% +couple today related to hybridization +because it really does help see these 3D + + align:start position:0% +because it really does help see these 3D + + + align:start position:0% +because it really does help see these 3D +orbitals right in their full shape and + + align:start position:0% +orbitals right in their full shape and + + + align:start position:0% +orbitals right in their full shape and +what's happening so I highly recommend + + align:start position:0% +what's happening so I highly recommend + + + align:start position:0% +what's happening so I highly recommend +if especially if you're having like some + + align:start position:0% +if especially if you're having like some + + + align:start position:0% +if especially if you're having like some +conceptual uh uh questions related to + + align:start position:0% +conceptual uh uh questions related to + + + align:start position:0% +conceptual uh uh questions related to +stuff we talked about Friday and today + + align:start position:0% +stuff we talked about Friday and today + + + align:start position:0% +stuff we talked about Friday and today +uh take a look at some of those videos + + align:start position:0% +uh take a look at some of those videos + + + align:start position:0% +uh take a look at some of those videos +now where we left off uh on Friday um + + align:start position:0% +now where we left off uh on Friday um + + + align:start position:0% +now where we left off uh on Friday um +before I get to nitrous Nitric oxide + + align:start position:0% +before I get to nitrous Nitric oxide + + + align:start position:0% +before I get to nitrous Nitric oxide +which has all those different uses in + + align:start position:0% +which has all those different uses in + + + align:start position:0% +which has all those different uses in +the world um and many more um we left + + align:start position:0% +the world um and many more um we left + + + align:start position:0% +the world um and many more um we left +off with the the the homonuclear dimers + + align:start position:0% +off with the the the homonuclear dimers + + + align:start position:0% +off with the the the homonuclear dimers +that's what we were doing on Friday + + align:start position:0% +that's what we were doing on Friday + + + align:start position:0% +that's what we were doing on Friday +right how do the atomic orbitals come + + align:start position:0% +right how do the atomic orbitals come + + + align:start position:0% +right how do the atomic orbitals come +together to make orbitals that are + + align:start position:0% +together to make orbitals that are + + + align:start position:0% +together to make orbitals that are +molecular MOS right um and and we did it + + align:start position:0% +molecular MOS right um and and we did it + + + align:start position:0% +molecular MOS right um and and we did it +for for dimers that have the same atom + + align:start position:0% +for for dimers that have the same atom + + + align:start position:0% +for for dimers that have the same atom +right and so here so we did nitrogen N2 + + align:start position:0% +right and so here so we did nitrogen N2 + + + align:start position:0% +right and so here so we did nitrogen N2 +and we did O2 right and so let's do that + + align:start position:0% +and we did O2 right and so let's do that + + + align:start position:0% +and we did O2 right and so let's do that +on the board and then because now we're + + align:start position:0% +on the board and then because now we're + + + align:start position:0% +on the board and then because now we're +going to start with one that has n and O + + align:start position:0% +going to start with one that has n and O + + + align:start position:0% +going to start with one that has n and O +heteronuclear dier right two different + + align:start position:0% +heteronuclear dier right two different + + + align:start position:0% +heteronuclear dier right two different +atoms but if I had the same one remember + + align:start position:0% +atoms but if I had the same one remember + + + align:start position:0% +atoms but if I had the same one remember +this is what it would look like right so + + align:start position:0% +this is what it would look like right so + + + align:start position:0% +this is what it would look like right so +here here would be say + + align:start position:0% +here here would be say + + + align:start position:0% +here here would be say +N2 would you know I'm going to just + + align:start position:0% +N2 would you know I'm going to just + + + align:start position:0% +N2 would you know I'm going to just +stick with the veence so the the + + align:start position:0% +stick with the veence so the the + + + align:start position:0% +stick with the veence so the the +2s for a nitrogen atom and the + + align:start position:0% +2s for a nitrogen atom and the + + + align:start position:0% +2s for a nitrogen atom and the +2p would have remember Hun's rule right + + align:start position:0% +2p would have remember Hun's rule right + + + align:start position:0% +2p would have remember Hun's rule right +okay so that's what the 2p would look + + align:start position:0% +okay so that's what the 2p would look + + + align:start position:0% +okay so that's what the 2p would look +like and then over here we would have + + align:start position:0% +like and then over here we would have + + + align:start position:0% +like and then over here we would have +uh the other atom This Is How We Roll + + align:start position:0% +uh the other atom This Is How We Roll + + + align:start position:0% +uh the other atom This Is How We Roll +when we talk about MOS and we'd have the + + align:start position:0% +when we talk about MOS and we'd have the + + + align:start position:0% +when we talk about MOS and we'd have the +2s over here and this is how we start + + align:start position:0% +2s over here and this is how we start + + + align:start position:0% +2s over here and this is how we start +these are my AOS for the two nitrogen + + align:start position:0% +these are my AOS for the two nitrogen + + + align:start position:0% +these are my AOS for the two nitrogen +atoms right this is what we did we're + + align:start position:0% +atoms right this is what we did we're + + + align:start position:0% +atoms right this is what we did we're +just getting back in the mood uh because + + align:start position:0% +just getting back in the mood uh because + + + align:start position:0% +just getting back in the mood uh because +we had the long weekend and when we make + + align:start position:0% +we had the long weekend and when we make + + + align:start position:0% +we had the long weekend and when we make +the OS remember we have all those sort + + align:start position:0% +the OS remember we have all those sort + + + align:start position:0% +the OS remember we have all those sort +of things that we talked about in terms + + align:start position:0% +of things that we talked about in terms + + + align:start position:0% +of things that we talked about in terms +of how these um this difference between + + align:start position:0% +of how these um this difference between + + + align:start position:0% +of how these um this difference between +the bonding and the anti-bonding orbital + + align:start position:0% +the bonding and the anti-bonding orbital + + + align:start position:0% +the bonding and the anti-bonding orbital +right uh is related to the the overlap + + align:start position:0% +right uh is related to the the overlap + + + align:start position:0% +right uh is related to the the overlap +and the same symmetry of the two AOS + + align:start position:0% +and the same symmetry of the two AOS + + + align:start position:0% +and the same symmetry of the two AOS +that come together we talked about that + + align:start position:0% +that come together we talked about that + + + align:start position:0% +that come together we talked about that +the more overlap the biggest this Delta + + align:start position:0% +the more overlap the biggest this Delta + + + align:start position:0% +the more overlap the biggest this Delta +gun typ right and then we also so that + + align:start position:0% +gun typ right and then we also so that + + + align:start position:0% +gun typ right and then we also so that +would be filled this would be filled + + align:start position:0% +would be filled this would be filled + + + align:start position:0% +would be filled this would be filled +right Sigma 2 s Sigma ah Sigma star 2s + + align:start position:0% +right Sigma 2 s Sigma ah Sigma star 2s + + + align:start position:0% +right Sigma 2 s Sigma ah Sigma star 2s +right uh and then for nitrogen we also + + align:start position:0% +right uh and then for nitrogen we also + + + align:start position:0% +right uh and then for nitrogen we also +talked about how oh boy these are + + align:start position:0% +talked about how oh boy these are + + + align:start position:0% +talked about how oh boy these are +reversed right see I'm I'm now already + + align:start position:0% +reversed right see I'm I'm now already + + + align:start position:0% +reversed right see I'm I'm now already +backwards twice which is not what I want + + align:start position:0% +backwards twice which is not what I want + + + align:start position:0% +backwards twice which is not what I want +okay and this was but this is the weird + + align:start position:0% +okay and this was but this is the weird + + + align:start position:0% +okay and this was but this is the weird +thing about nitrogen because if we go to + + align:start position:0% +thing about nitrogen because if we go to + + + align:start position:0% +thing about nitrogen because if we go to +oxygen then the way it goes is you know + + align:start position:0% +oxygen then the way it goes is you know + + + align:start position:0% +oxygen then the way it goes is you know +you got your 2s and + + align:start position:0% +you got your 2s and + + + align:start position:0% +you got your 2s and +oxygen okay and in oxygen you've got + + align:start position:0% +oxygen okay and in oxygen you've got + + + align:start position:0% +oxygen okay and in oxygen you've got +your your six veence electrons in the + + align:start position:0% +your your six veence electrons in the + + + align:start position:0% +your your six veence electrons in the +2p and over here you've also got the + + align:start position:0% +2p and over here you've also got the + + + align:start position:0% +2p and over here you've also got the +same + + align:start position:0% +same + + + align:start position:0% +same +okay and you've also got the 2s and but + + align:start position:0% +okay and you've also got the 2s and but + + + align:start position:0% +okay and you've also got the 2s and but +for + + align:start position:0% + + + + align:start position:0% + +oxygen okay so those are the sigma Sigma + + align:start position:0% +oxygen okay so those are the sigma Sigma + + + align:start position:0% +oxygen okay so those are the sigma Sigma +star but for oxygen we go to the + + align:start position:0% + + + + align:start position:0% + +ordering that + + align:start position:0% +ordering that + + + align:start position:0% +ordering that +we usually have which is that remember + + align:start position:0% +we usually have which is that remember + + + align:start position:0% +we usually have which is that remember +those Pi + + align:start position:0% +those Pi + + + align:start position:0% +those Pi +orbitals have and this isn't necessarily + + align:start position:0% +orbitals have and this isn't necessarily + + + align:start position:0% +orbitals have and this isn't necessarily +drawn to scale but those Pi or right so + + align:start position:0% +drawn to scale but those Pi or right so + + + align:start position:0% +drawn to scale but those Pi or right so +this is Sigma Sigma star and these are + + align:start position:0% +this is Sigma Sigma star and these are + + + align:start position:0% +this is Sigma Sigma star and these are +the pi orbitals pi and Pi Star + + align:start position:0% +the pi orbitals pi and Pi Star + + + align:start position:0% +the pi orbitals pi and Pi Star +right Sigma + + align:start position:0% +right Sigma + + + align:start position:0% +right Sigma +P Sigma P right 2 p 2s Sigma this would + + align:start position:0% +P Sigma P right 2 p 2s Sigma this would + + + align:start position:0% +P Sigma P right 2 p 2s Sigma this would +be Sigma s Sigma 2s Sigma 2 s star Sigma + + align:start position:0% +be Sigma s Sigma 2s Sigma 2 s star Sigma + + + align:start position:0% +be Sigma s Sigma 2s Sigma 2 s star Sigma +2 p if you want to be exact about it + + align:start position:0% +2 p if you want to be exact about it + + + align:start position:0% +2 p if you want to be exact about it +Sigma 2 p star pix Pi y pix star Pi y + + align:start position:0% +Sigma 2 p star pix Pi y pix star Pi y + + + align:start position:0% +Sigma 2 p star pix Pi y pix star Pi y +star we talked about all this on Friday + + align:start position:0% +star we talked about all this on Friday + + + align:start position:0% +star we talked about all this on Friday +I'm just getting us back in the mood but + + align:start position:0% +I'm just getting us back in the mood but + + + align:start position:0% +I'm just getting us back in the mood but +the but the way we left off was that + + align:start position:0% +the but the way we left off was that + + + align:start position:0% +the but the way we left off was that +these are okay so for if I fill these + + align:start position:0% +these are okay so for if I fill these + + + align:start position:0% +these are okay so for if I fill these +all up now right remember we do the mo + + align:start position:0% +all up now right remember we do the mo + + + align:start position:0% +all up now right remember we do the mo +filling then we'd have this and this and + + align:start position:0% +filling then we'd have this and this and + + + align:start position:0% +filling then we'd have this and this and +O now hold on Yep this and there and + + align:start position:0% +O now hold on Yep this and there and + + + align:start position:0% +O now hold on Yep this and there and +there for oxygen and then over here + + align:start position:0% +there for oxygen and then over here + + + align:start position:0% +there for oxygen and then over here +we're filling them up we got those are + + align:start position:0% +we're filling them up we got those are + + + align:start position:0% +we're filling them up we got those are +filled those are filled and this is + + align:start position:0% +filled those are filled and this is + + + align:start position:0% +filled those are filled and this is +filled filled for nitrogen remember I + + align:start position:0% +filled filled for nitrogen remember I + + + align:start position:0% +filled filled for nitrogen remember I +showed the movie pouring liquid oxygen + + align:start position:0% +showed the movie pouring liquid oxygen + + + align:start position:0% +showed the movie pouring liquid oxygen +pouring liquid nitrogen oxygen has + + align:start position:0% +pouring liquid nitrogen oxygen has + + + align:start position:0% +pouring liquid nitrogen oxygen has +unpaired + + align:start position:0% +unpaired + + + align:start position:0% +unpaired +electrons which means it's + + align:start position:0% +electrons which means it's + + + align:start position:0% +electrons which means it's +paramagnetic it has unpaired electrons + + align:start position:0% +paramagnetic it has unpaired electrons + + + align:start position:0% +paramagnetic it has unpaired electrons +the O2 dier this is O2 these are Theos + + align:start position:0% +the O2 dier this is O2 these are Theos + + + align:start position:0% +the O2 dier this is O2 these are Theos +of o2 these are the atoms these are + + align:start position:0% +of o2 these are the atoms these are + + + align:start position:0% +of o2 these are the atoms these are +Theos of N2 N2 doesn't have any unpaired + + align:start position:0% +Theos of N2 N2 doesn't have any unpaired + + + align:start position:0% +Theos of N2 N2 doesn't have any unpaired +electrons so it's not paramagnetic um + + align:start position:0% +electrons so it's not paramagnetic um + + + align:start position:0% +electrons so it's not paramagnetic um +but the thing that we left off on that's + + align:start position:0% +but the thing that we left off on that's + + + align:start position:0% +but the thing that we left off on that's +what I'm saying is that these two switch + + align:start position:0% +what I'm saying is that these two switch + + + align:start position:0% +what I'm saying is that these two switch +order + + align:start position:0% + + + + align:start position:0% + +for those diers for lithium through + + align:start position:0% +for those diers for lithium through + + + align:start position:0% +for those diers for lithium through +nitrogen those two switch over and we + + align:start position:0% +nitrogen those two switch over and we + + + align:start position:0% +nitrogen those two switch over and we +talk about that on Friday the reason is + + align:start position:0% +talk about that on Friday the reason is + + + align:start position:0% +talk about that on Friday the reason is +because for those atoms these uh + + align:start position:0% +because for those atoms these uh + + + align:start position:0% +because for those atoms these uh +Sigma these Sigma uh uh P orbitals can + + align:start position:0% +Sigma these Sigma uh uh P orbitals can + + + align:start position:0% +Sigma these Sigma uh uh P orbitals can +mix in with the sigma s orbitals and so + + align:start position:0% +mix in with the sigma s orbitals and so + + + align:start position:0% +mix in with the sigma s orbitals and so +you get more because remember the more + + align:start position:0% +you get more because remember the more + + + align:start position:0% +you get more because remember the more +overlap the greater the energy right the + + align:start position:0% +overlap the greater the energy right the + + + align:start position:0% +overlap the greater the energy right the +greater that Delta between bonding and + + align:start position:0% +greater that Delta between bonding and + + + align:start position:0% +greater that Delta between bonding and +antibonding right so the more mixing you + + align:start position:0% +antibonding right so the more mixing you + + + align:start position:0% +antibonding right so the more mixing you +have the more spread you get and it's so + + align:start position:0% +have the more spread you get and it's so + + + align:start position:0% +have the more spread you get and it's so +much that for those diers you you push + + align:start position:0% +much that for those diers you you push + + + align:start position:0% +much that for those diers you you push +the orbital up okay that's all what we + + align:start position:0% +the orbital up okay that's all what we + + + align:start position:0% +the orbital up okay that's all what we +talked about Friday now I got one of + + align:start position:0% +talked about Friday now I got one of + + + align:start position:0% +talked about Friday now I got one of +each and I wanted these on the board so + + align:start position:0% +each and I wanted these on the board so + + + align:start position:0% +each and I wanted these on the board so +that you can see them as we now take one + + align:start position:0% +that you can see them as we now take one + + + align:start position:0% +that you can see them as we now take one +atom from one side and one from the + + align:start position:0% +atom from one side and one from the + + + align:start position:0% +atom from one side and one from the +other it's + + align:start position:0% +other it's + + + align:start position:0% +other it's +actually kind of what you expect you + + align:start position:0% +actually kind of what you expect you + + + align:start position:0% +actually kind of what you expect you +just have to have one thing in mind when + + align:start position:0% +just have to have one thing in mind when + + + align:start position:0% +just have to have one thing in mind when +you think about n o so if this is n okay + + align:start position:0% +you think about n o so if this is n okay + + + align:start position:0% +you think about n o so if this is n okay +over here and we're going to put uh 2 s + + align:start position:0% +over here and we're going to put uh 2 s + + + align:start position:0% +over here and we're going to put uh 2 s +there and 2 p there here here here here + + align:start position:0% +there and 2 p there here here here here + + + align:start position:0% +there and 2 p there here here here here +there's my n atom and now I've got o + + align:start position:0% +there's my n atom and now I've got o + + + align:start position:0% +there's my n atom and now I've got o +over here so I've got my but now see the + + align:start position:0% +over here so I've got my but now see the + + + align:start position:0% +over here so I've got my but now see the +thing is O is more Electro negative and + + align:start position:0% +thing is O is more Electro negative and + + + align:start position:0% +thing is O is more Electro negative and +the way this works for a heteronuclear + + align:start position:0% +the way this works for a heteronuclear + + + align:start position:0% +the way this works for a heteronuclear +dimer is + + align:start position:0% +dimer is + + + align:start position:0% +dimer is +let's write this on the board so for a + + align:start position:0% +let's write this on the board so for a + + + align:start position:0% +let's write this on the board so for a +hetero nuclear that means that the two + + align:start position:0% +hetero nuclear that means that the two + + + align:start position:0% +hetero nuclear that means that the two +atoms are different okay but for a + + align:start position:0% +atoms are different okay but for a + + + align:start position:0% +atoms are different okay but for a +heteronuclear + + align:start position:0% +heteronuclear + + + align:start position:0% +heteronuclear +dimer um the bonding + + align:start position:0% + + + + align:start position:0% + +os are + + align:start position:0% + + + + align:start position:0% + +closer in + + align:start position:0% +closer in + + + align:start position:0% +closer in +energy to the more electronegative atom + + align:start position:0% +energy to the more electronegative atom + + + align:start position:0% +energy to the more electronegative atom +electr + + align:start position:0% +electr + + + align:start position:0% +electr +NE + + align:start position:0% + + + + align:start position:0% + +atom atom so what that means is that if + + align:start position:0% +atom atom so what that means is that if + + + align:start position:0% +atom atom so what that means is that if +I draw so if I draw my oxygen levels but + + align:start position:0% +I draw so if I draw my oxygen levels but + + + align:start position:0% +I draw so if I draw my oxygen levels but +you know this right you know this also + + align:start position:0% +you know this right you know this also + + + align:start position:0% +you know this right you know this also +from all the the work we did on + + align:start position:0% +from all the the work we did on + + + align:start position:0% +from all the the work we did on +atoms right you know a little something + + align:start position:0% +atoms right you know a little something + + + align:start position:0% +atoms right you know a little something +about remember this axis is + + align:start position:0% +about remember this axis is + + + align:start position:0% +about remember this axis is +energy this axis is energy right + + align:start position:0% +energy this axis is energy right + + + align:start position:0% +energy this axis is energy right +and so if this is 2s for oxygen and then + + align:start position:0% +and so if this is 2s for oxygen and then + + + align:start position:0% +and so if this is 2s for oxygen and then +the two PS are going to be sort of like + + align:start position:0% +the two PS are going to be sort of like + + + align:start position:0% +the two PS are going to be sort of like +here + + align:start position:0% +here + + + align:start position:0% +here +okay and we'll fill them up thinking + + align:start position:0% +okay and we'll fill them up thinking + + + align:start position:0% +okay and we'll fill them up thinking +about Huns rule well now what we're + + align:start position:0% +about Huns rule well now what we're + + + align:start position:0% +about Huns rule well now what we're +going to have is that those the MOs for + + align:start position:0% +going to have is that those the MOs for + + + align:start position:0% +going to have is that those the MOs for +the N + + align:start position:0% +the N + + + align:start position:0% +the N +molecule are going to come closer + + align:start position:0% +molecule are going to come closer + + + align:start position:0% +molecule are going to come closer +they're going to come further down from + + align:start position:0% +they're going to come further down from + + + align:start position:0% +they're going to come further down from +that side right than they come from that + + align:start position:0% +that side right than they come from that + + + align:start position:0% +that side right than they come from that +side you see that there's an asymmetry I + + align:start position:0% +side you see that there's an asymmetry I + + + align:start position:0% +side you see that there's an asymmetry I +made it kind of subtle I made it kind + + align:start position:0% +made it kind of subtle I made it kind + + + align:start position:0% +made it kind of subtle I made it kind +and why is this curved that's not good + + align:start position:0% +and why is this curved that's not good + + + align:start position:0% +and why is this curved that's not good +what's going on here there's a little + + align:start position:0% +what's going on here there's a little + + + align:start position:0% +what's going on here there's a little +bit of an asymmetry here + + align:start position:0% +bit of an asymmetry here + + + align:start position:0% +bit of an asymmetry here +right + + align:start position:0% +right + + + align:start position:0% +right +so so this is lower + + align:start position:0% +so so this is lower + + + align:start position:0% +so so this is lower +down these are lower down right so when + + align:start position:0% +down these are lower down right so when + + + align:start position:0% +down these are lower down right so when +you draw your orbitals now oh man I'm + + align:start position:0% +you draw your orbitals now oh man I'm + + + align:start position:0% +you draw your orbitals now oh man I'm +going to draw this a little bit + + align:start position:0% +going to draw this a little bit + + + align:start position:0% +going to draw this a little bit +lower right + + align:start position:0% +lower right + + + align:start position:0% +lower right +so now when you draw them you see that + + align:start position:0% +so now when you draw them you see that + + + align:start position:0% +so now when you draw them you see that +bonding orbital is going to be + + align:start position:0% +bonding orbital is going to be + + + align:start position:0% +bonding orbital is going to be +closer you see this is a bonding orbital + + align:start position:0% +closer you see this is a bonding orbital + + + align:start position:0% +closer you see this is a bonding orbital +still it's still bonding right it's a + + align:start position:0% +still it's still bonding right it's a + + + align:start position:0% +still it's still bonding right it's a +it's going to be a a sigma P Sigma 2 p + + align:start position:0% +it's going to be a a sigma P Sigma 2 p + + + align:start position:0% +it's going to be a a sigma P Sigma 2 p +but it's closer and energy to the more + + align:start position:0% +but it's closer and energy to the more + + + align:start position:0% +but it's closer and energy to the more +electronegative levels you see that + + align:start position:0% +electronegative levels you see that + + + align:start position:0% +electronegative levels you see that +right so it's not symmetric + + align:start position:0% +right so it's not symmetric + + + align:start position:0% +right so it's not symmetric +anymore okay and then the same would + + align:start position:0% +anymore okay and then the same would + + + align:start position:0% +anymore okay and then the same would +happen with these guys right they'd be + + align:start position:0% +happen with these guys right they'd be + + + align:start position:0% +happen with these guys right they'd be +closer in energy + + align:start position:0% +closer in energy + + + align:start position:0% +closer in energy +to the yeah they would be closer and I'm + + align:start position:0% +to the yeah they would be closer and I'm + + + align:start position:0% +to the yeah they would be closer and I'm +not leaving myself enough room here + + align:start position:0% +not leaving myself enough room here + + + align:start position:0% +not leaving myself enough room here +that's why I've got some videos they do + + align:start position:0% +that's why I've got some videos they do + + + align:start position:0% +that's why I've got some videos they do +it better + + align:start position:0% +it better + + + align:start position:0% +it better +right okay we'll leave that one there + + align:start position:0% +right okay we'll leave that one there + + + align:start position:0% +right okay we'll leave that one there +it's a little bit + + align:start position:0% +it's a little bit + + + align:start position:0% +it's a little bit +better not much but a little + + align:start position:0% +better not much but a little + + + align:start position:0% +better not much but a little +bit so the B now oh by the way it for no + + align:start position:0% +bit so the B now oh by the way it for no + + + align:start position:0% +bit so the B now oh by the way it for no +o let's talk about Mo for a second cuz + + align:start position:0% +o let's talk about Mo for a second cuz + + + align:start position:0% +o let's talk about Mo for a second cuz +there's another thing that's important + + align:start position:0% +there's another thing that's important + + + align:start position:0% +there's another thing that's important +that we talk about which is bond order + + align:start position:0% +that we talk about which is bond order + + + align:start position:0% +that we talk about which is bond order +and you know so the bond oh electron + + align:start position:0% +and you know so the bond oh electron + + + align:start position:0% +and you know so the bond oh electron +configuration is another thing right so + + align:start position:0% +configuration is another thing right so + + + align:start position:0% +configuration is another thing right so +like the the + + align:start position:0% +like the the + + + align:start position:0% +like the the +configuration we can write this + + align:start position:0% +configuration we can write this + + + align:start position:0% +configuration we can write this +out right so the configuration of say O2 + + align:start position:0% +out right so the configuration of say O2 + + + align:start position:0% +out right so the configuration of say O2 +would be Sigma 2s right you're just + + align:start position:0% +would be Sigma 2s right you're just + + + align:start position:0% +would be Sigma 2s right you're just +filling them up with two electrons Sigma + + align:start position:0% +filling them up with two electrons Sigma + + + align:start position:0% +filling them up with two electrons Sigma +star 2s with two electrons Sigma 2 + + align:start position:0% +star 2s with two electrons Sigma 2 + + + align:start position:0% +star 2s with two electrons Sigma 2 +p with two electrons pi + + align:start position:0% +p with two electrons pi + + + align:start position:0% +p with two electrons pi +2 p with four electrons and then Pi 2 p + + align:start position:0% +2 p with four electrons and then Pi 2 p + + + align:start position:0% +2 p with four electrons and then Pi 2 p +star with two electrons that's how that + + align:start position:0% +star with two electrons that's how that + + + align:start position:0% +star with two electrons that's how that +looks it's a little bit messy but I hope + + align:start position:0% +looks it's a little bit messy but I hope + + + align:start position:0% +looks it's a little bit messy but I hope +you can read it that's just reading up + + align:start position:0% +you can read it that's just reading up + + + align:start position:0% +you can read it that's just reading up +right it's the electron configuration of + + align:start position:0% +right it's the electron configuration of + + + align:start position:0% +right it's the electron configuration of +the + + align:start position:0% +the + + + align:start position:0% +the +MOs just like we would write the SPD + + align:start position:0% +MOs just like we would write the SPD + + + align:start position:0% +MOs just like we would write the SPD +electron configuration of atoms but this + + align:start position:0% +electron configuration of atoms but this + + + align:start position:0% +electron configuration of atoms but this +is a + + align:start position:0% +is a + + + align:start position:0% +is a +molecule now sometimes you might you + + align:start position:0% +molecule now sometimes you might you + + + align:start position:0% +molecule now sometimes you might you +know some say there's a convention we + + align:start position:0% +know some say there's a convention we + + + align:start position:0% +know some say there's a convention we +use which is that the pz is the sigma ah + + align:start position:0% +use which is that the pz is the sigma ah + + + align:start position:0% +use which is that the pz is the sigma ah +nobody can agree on so different + + align:start position:0% +nobody can agree on so different + + + align:start position:0% +nobody can agree on so different +textbooks say PX P but we were saying P + + align:start position:0% +textbooks say PX P but we were saying P + + + align:start position:0% +textbooks say PX P but we were saying P +if pz is Sigma then this would be like a + + align:start position:0% +if pz is Sigma then this would be like a + + + align:start position:0% +if pz is Sigma then this would be like a +sigma 2 + + align:start position:0% +sigma 2 + + + align:start position:0% +sigma 2 +pz right and and you might if you really + + align:start position:0% +pz right and and you might if you really + + + align:start position:0% +pz right and and you might if you really +want to write this you know you might + + align:start position:0% +want to write this you know you might + + + align:start position:0% +want to write this you know you might +write that that's Pi 2 PX if you really + + align:start position:0% +write that that's Pi 2 PX if you really + + + align:start position:0% +write that that's Pi 2 PX if you really +want to keep track of it there's two + + align:start position:0% +want to keep track of it there's two + + + align:start position:0% +want to keep track of it there's two +orbitals in there you didn't fill one + + align:start position:0% +orbitals in there you didn't fill one + + + align:start position:0% +orbitals in there you didn't fill one +orbital with four electrons right so + + align:start position:0% +orbital with four electrons right so + + + align:start position:0% +orbital with four electrons right so +this would be Pi 2 PX and pi 2 py for + + align:start position:0% +this would be Pi 2 PX and pi 2 py for + + + align:start position:0% +this would be Pi 2 PX and pi 2 py for +right that's what's happening in there + + align:start position:0% +right that's what's happening in there + + + align:start position:0% +right that's what's happening in there +okay but the other thing you can see + + align:start position:0% +okay but the other thing you can see + + + align:start position:0% +okay but the other thing you can see +from the bond from this this filling is + + align:start position:0% +from the bond from this this filling is + + + align:start position:0% +from the bond from this this filling is +also the bond order right and so for the + + align:start position:0% +also the bond order right and so for the + + + align:start position:0% +also the bond order right and so for the +bond order + + align:start position:0% +bond order + + + align:start position:0% +bond order +bond + + align:start position:0% +bond + + + align:start position:0% +bond +order here you would have a half times + + align:start position:0% +order here you would have a half times + + + align:start position:0% +order here you would have a half times +and it's all of the remember the bond is + + align:start position:0% +and it's all of the remember the bond is + + + align:start position:0% +and it's all of the remember the bond is +all of the bonding electrons minus + + align:start position:0% +all of the bonding electrons minus + + + align:start position:0% +all of the bonding electrons minus +antibinding electrons divided by two + + align:start position:0% +antibinding electrons divided by two + + + align:start position:0% +antibinding electrons divided by two +right and and if it's zero it's not a + + align:start position:0% +right and and if it's zero it's not a + + + align:start position:0% +right and and if it's zero it's not a +stable molecule if it's greater than + + align:start position:0% +stable molecule if it's greater than + + + align:start position:0% +stable molecule if it's greater than +zero stable and the higher the bond + + align:start position:0% +zero stable and the higher the bond + + + align:start position:0% +zero stable and the higher the bond +order the higher the bond strength right + + align:start position:0% +order the higher the bond strength right + + + align:start position:0% +order the higher the bond strength right +so that's also from Friday and so this + + align:start position:0% +so that's also from Friday and so this + + + align:start position:0% +so that's also from Friday and so this +is 2 - 2 + 4 - 2 and so you get + + align:start position:0% +is 2 - 2 + 4 - 2 and so you get + + + align:start position:0% +is 2 - 2 + 4 - 2 and so you get +two nope I missed a + + align:start position:0% +two nope I missed a + + + align:start position:0% +two nope I missed a +two + 2 + 4 - + + align:start position:0% +two + 2 + 4 - + + + align:start position:0% +two + 2 + 4 - +2 2 - 2 that kind of cancels out right + + + align:start position:0% +2 2 - 2 that kind of cancels out right + + + + align:start position:0% +2 2 - 2 that kind of cancels out right + +2 + 4 - 2 all divided by two so the the + + align:start position:0% +2 + 4 - 2 all divided by two so the the + + + align:start position:0% +2 + 4 - 2 all divided by two so the the +bond order for oxy now the bond order + + align:start position:0% +bond order for oxy now the bond order + + + align:start position:0% +bond order for oxy now the bond order +for no + + align:start position:0% +for no + + + align:start position:0% +for no +o bond order for no + + align:start position:0% +o bond order for no + + + align:start position:0% +o bond order for no +o is going to be uh 2.5 well it's kind + + align:start position:0% +o is going to be uh 2.5 well it's kind + + + align:start position:0% +o is going to be uh 2.5 well it's kind +of interesting now you can see okay so n + + align:start position:0% +of interesting now you can see okay so n + + + align:start position:0% +of interesting now you can see okay so n +o is stronger uh more strongly bound + + align:start position:0% +o is stronger uh more strongly bound + + + align:start position:0% +o is stronger uh more strongly bound +than O2 less strongly bound than N2 and + + align:start position:0% +than O2 less strongly bound than N2 and + + + align:start position:0% +than O2 less strongly bound than N2 and +it's kind of interesting how can I make + + align:start position:0% +it's kind of interesting how can I make + + + align:start position:0% +it's kind of interesting how can I make +n o a stronger a more strongly bound + + align:start position:0% +n o a stronger a more strongly bound + + + align:start position:0% +n o a stronger a more strongly bound +molecule well I can take an electron + + align:start position:0% +molecule well I can take an electron + + + align:start position:0% +molecule well I can take an electron +away which is a little bit + + align:start position:0% +away which is a little bit + + + align:start position:0% +away which is a little bit +counterintuitive right because for no + + align:start position:0% +counterintuitive right because for no + + + align:start position:0% +counterintuitive right because for no +O+ the bond order goes up because the + + align:start position:0% +O+ the bond order goes up because the + + + align:start position:0% +O+ the bond order goes up because the +electron that I've taken away was in an + + align:start position:0% +electron that I've taken away was in an + + + align:start position:0% +electron that I've taken away was in an +anti-bonding orbital right so no o plus + + align:start position:0% +anti-bonding orbital right so no o plus + + + align:start position:0% +anti-bonding orbital right so no o plus +actually has a stronger Bond than n o + + align:start position:0% +actually has a stronger Bond than n o + + + align:start position:0% +actually has a stronger Bond than n o +even though it has one less electron you + + align:start position:0% +even though it has one less electron you + + + align:start position:0% +even though it has one less electron you +get this all from just looking at which + + align:start position:0% +get this all from just looking at which + + + align:start position:0% +get this all from just looking at which +electrons are occupying which orbitals + + align:start position:0% +electrons are occupying which orbitals + + + align:start position:0% +electrons are occupying which orbitals +ah on in this case you had in this very + + align:start position:0% +ah on in this case you had in this very + + + align:start position:0% +ah on in this case you had in this very +much not drawn to scale oh boy figure + + align:start position:0% +much not drawn to scale oh boy figure + + + align:start position:0% +much not drawn to scale oh boy figure +right what you had was one up + + align:start position:0% +right what you had was one up + + + align:start position:0% +right what you had was one up +there so if I take that out my bond + + align:start position:0% +there so if I take that out my bond + + + align:start position:0% +there so if I take that out my bond +order increases right okay all + + align:start position:0% +order increases right okay all + + + align:start position:0% +order increases right okay all +right and the last point I wanted to + + align:start position:0% +right and the last point I wanted to + + + align:start position:0% +right and the last point I wanted to +make about Mo Theory before we talk + + align:start position:0% +make about Mo Theory before we talk + + + align:start position:0% +make about Mo Theory before we talk +about hybridization is with one other + + align:start position:0% +about hybridization is with one other + + + align:start position:0% +about hybridization is with one other +example and that's + + align:start position:0% + + + + align:start position:0% + +HCL okay so for htl you got something + + align:start position:0% +HCL okay so for htl you got something + + + align:start position:0% +HCL okay so for htl you got something +else happening that's important so we + + align:start position:0% +else happening that's important so we + + + align:start position:0% +else happening that's important so we +just talked about electro negativity + + align:start position:0% +just talked about electro negativity + + + align:start position:0% +just talked about electro negativity +driving where the you know that this is + + align:start position:0% +driving where the you know that this is + + + align:start position:0% +driving where the you know that this is +tilted okay fine and now we got the fact + + align:start position:0% +tilted okay fine and now we got the fact + + + align:start position:0% +tilted okay fine and now we got the fact +that chlorine comes into the situation + + align:start position:0% +that chlorine comes into the situation + + + align:start position:0% +that chlorine comes into the situation +you know it's like chlorine is like hey + + align:start position:0% +you know it's like chlorine is like hey + + + align:start position:0% +you know it's like chlorine is like hey +I got seven electrons right and hydrogen + + align:start position:0% +I got seven electrons right and hydrogen + + + align:start position:0% +I got seven electrons right and hydrogen +is like hey I got + + align:start position:0% +is like hey I got + + + align:start position:0% +is like hey I got +one so how does this work right so this + + align:start position:0% +one so how does this work right so this + + + align:start position:0% +one so how does this work right so this +gets to what was brought up uh Friday + + align:start position:0% +gets to what was brought up uh Friday + + + align:start position:0% +gets to what was brought up uh Friday +which is there's another type of Mo and + + align:start position:0% +which is there's another type of Mo and + + + align:start position:0% +which is there's another type of Mo and +it's not bonding and it's not + + align:start position:0% +it's not bonding and it's not + + + align:start position:0% +it's not bonding and it's not +anti-bonding it's + + align:start position:0% +anti-bonding it's + + + align:start position:0% +anti-bonding it's +nonbonding that is not the same as + + align:start position:0% +nonbonding that is not the same as + + + align:start position:0% +nonbonding that is not the same as +antibonding non-bonding doesn't take + + align:start position:0% +antibonding non-bonding doesn't take + + + align:start position:0% +antibonding non-bonding doesn't take +sides it just is because the way this + + align:start position:0% +sides it just is because the way this + + + align:start position:0% +sides it just is because the way this +works is you know hydrogen comes at this + + align:start position:0% +works is you know hydrogen comes at this + + + align:start position:0% +works is you know hydrogen comes at this +okay so hydrogen's up here with its 1 s + + align:start position:0% +okay so hydrogen's up here with its 1 s + + + align:start position:0% +okay so hydrogen's up here with its 1 s +chlorine is you know let's say over here + + align:start position:0% +chlorine is you know let's say over here + + + align:start position:0% +chlorine is you know let's say over here +it's got 3 S filled and it's got uh + + align:start position:0% +it's got 3 S filled and it's got uh + + + align:start position:0% +it's got 3 S filled and it's got uh +let's draw these you know here okay + + align:start position:0% +let's draw these you know here okay + + + align:start position:0% +let's draw these you know here okay +3 p and chlorine got seven electrons in + + align:start position:0% +3 p and chlorine got seven electrons in + + + align:start position:0% +3 p and chlorine got seven electrons in +the + + align:start position:0% +the + + + align:start position:0% +the +3p do they do they all come together and + + align:start position:0% +3p do they do they all come together and + + + align:start position:0% +3p do they do they all come together and +formos no they can't because there's + + align:start position:0% +formos no they can't because there's + + + align:start position:0% +formos no they can't because there's +only one on this side right so this one + + align:start position:0% +only one on this side right so this one + + + align:start position:0% +only one on this side right so this one +orbital will form let me ah let me make + + align:start position:0% +orbital will form let me ah let me make + + + align:start position:0% +orbital will form let me ah let me make +myself enough space so I'm going to + + align:start position:0% +myself enough space so I'm going to + + + align:start position:0% +myself enough space so I'm going to +exaggerate this a little bit so this one + + align:start position:0% +exaggerate this a little bit so this one + + + align:start position:0% +exaggerate this a little bit so this one +orbital will will + + align:start position:0% +orbital will will + + + align:start position:0% +orbital will will +form a sigma Bond Sigma uh 3 p Sigma 3p + + align:start position:0% +form a sigma Bond Sigma uh 3 p Sigma 3p + + + align:start position:0% +form a sigma Bond Sigma uh 3 p Sigma 3p +bond this would be a sigma 3p star now + + align:start position:0% +bond this would be a sigma 3p star now + + + align:start position:0% +bond this would be a sigma 3p star now +that's + + align:start position:0% +that's + + + align:start position:0% +that's +exactly what we've already done right + + align:start position:0% +exactly what we've already done right + + + align:start position:0% +exactly what we've already done right +the the sigma + + align:start position:0% +the the sigma + + + align:start position:0% +the the sigma +but but oh there's something a little + + align:start position:0% +but but oh there's something a little + + + align:start position:0% +but but oh there's something a little +interesting about this one right because + + align:start position:0% +interesting about this one right because + + + align:start position:0% +interesting about this one right because +it's an + + align:start position:0% +it's an + + + align:start position:0% +it's an +S it's an S but that's okay because the + + align:start position:0% +S it's an S but that's okay because the + + + align:start position:0% +S it's an S but that's okay because the +S can talk to a sigma P this we talking + + align:start position:0% +S can talk to a sigma P this we talking + + + align:start position:0% +S can talk to a sigma P this we talking +about this the S can talk to this that's + + align:start position:0% +about this the S can talk to this that's + + + align:start position:0% +about this the S can talk to this that's +okay cuz it's + + align:start position:0% +okay cuz it's + + + align:start position:0% +okay cuz it's +aligned right now but these guys don't + + align:start position:0% +aligned right now but these guys don't + + + align:start position:0% +aligned right now but these guys don't +have anyone to talk to they don't so + + align:start position:0% +have anyone to talk to they don't so + + + align:start position:0% +have anyone to talk to they don't so +they can't make their Pi orbitals they + + align:start position:0% +they can't make their Pi orbitals they + + + align:start position:0% +they can't make their Pi orbitals they +can't do that and so they just stay + + align:start position:0% +can't do that and so they just stay + + + align:start position:0% +can't do that and so they just stay +there these stay there exactly at the + + align:start position:0% +there these stay there exactly at the + + + align:start position:0% +there these stay there exactly at the +same place they're not doing anything + + align:start position:0% +same place they're not doing anything + + + align:start position:0% +same place they're not doing anything +different they're just hanging out those + + align:start position:0% +different they're just hanging out those + + + align:start position:0% +different they're just hanging out those +electrons are non-bonding so these are + + align:start position:0% +electrons are non-bonding so these are + + + align:start position:0% +electrons are non-bonding so these are +not these are not Pi orbitals + + align:start position:0% +not these are not Pi orbitals + + + align:start position:0% +not these are not Pi orbitals +Sigma and Pi are special names they + + align:start position:0% +Sigma and Pi are special names they + + + align:start position:0% +Sigma and Pi are special names they +refer to these orbitals that of the of + + align:start position:0% +refer to these orbitals that of the of + + + align:start position:0% +refer to these orbitals that of the of +the molecule that involve the lcao the + + align:start position:0% +the molecule that involve the lcao the + + + align:start position:0% +the molecule that involve the lcao the +linear combination of the atomic + + align:start position:0% +linear combination of the atomic + + + align:start position:0% +linear combination of the atomic +orbitals these do + + align:start position:0% +orbitals these do + + + align:start position:0% +orbitals these do +not n b n + + align:start position:0% +not n b n + + + align:start position:0% +not n b n +b that's what we'll call them just to be + + align:start position:0% +b that's what we'll call them just to be + + + align:start position:0% +b that's what we'll call them just to be +very clear just to be very clear now + + align:start position:0% +very clear just to be very clear now + + + align:start position:0% +very clear just to be very clear now +they're filled they're filled and they + + align:start position:0% +they're filled they're filled and they + + + align:start position:0% +they're filled they're filled and they +do not count count in the bond order by + + align:start position:0% +do not count count in the bond order by + + + align:start position:0% +do not count count in the bond order by +the way this is also a + + align:start position:0% +the way this is also a + + + align:start position:0% +the way this is also a +nonbonding + + align:start position:0% +nonbonding + + + align:start position:0% +nonbonding +orbital that's a non-bonding + + align:start position:0% +orbital that's a non-bonding + + + align:start position:0% +orbital that's a non-bonding +orbital nonbonding orbitals these are + + align:start position:0% +orbital nonbonding orbitals these are + + + align:start position:0% +orbital nonbonding orbitals these are +not going to count so in the bond + + align:start position:0% +not going to count so in the bond + + + align:start position:0% +not going to count so in the bond +order you only have you have 12 * 2 - 0 + + align:start position:0% +order you only have you have 12 * 2 - 0 + + + align:start position:0% +order you only have you have 12 * 2 - 0 +equals 1 these do not participate in + + align:start position:0% +equals 1 these do not participate in + + + align:start position:0% +equals 1 these do not participate in +bonding I got to fill this two electrons + + align:start position:0% +bonding I got to fill this two electrons + + + align:start position:0% +bonding I got to fill this two electrons +are in that + + align:start position:0% +are in that + + + align:start position:0% +are in that +one okay so that's another example of + + align:start position:0% +one okay so that's another example of + + + align:start position:0% +one okay so that's another example of +something that happens in these Mo + + align:start position:0% +something that happens in these Mo + + + align:start position:0% +something that happens in these Mo +diagrams one of them brought too many + + align:start position:0% +diagrams one of them brought too many + + + align:start position:0% +diagrams one of them brought too many +electrons to the party and so there's no + + align:start position:0% +electrons to the party and so there's no + + + align:start position:0% +electrons to the party and so there's no +one to to to to talk to but it's okay + + align:start position:0% +one to to to to talk to but it's okay + + + align:start position:0% +one to to to to talk to but it's okay +they're just going to stay there and + + align:start position:0% +they're just going to stay there and + + + align:start position:0% +they're just going to stay there and +wait maybe something else will come + + align:start position:0% +wait maybe something else will come + + + align:start position:0% +wait maybe something else will come +along right okay now that is right there + + align:start position:0% +along right okay now that is right there + + + align:start position:0% +along right okay now that is right there +what I just drew look at that 2 p 2s and + + align:start position:0% +what I just drew look at that 2 p 2s and + + + align:start position:0% +what I just drew look at that 2 p 2s and +you get this thing right oh that's a + + align:start position:0% +you get this thing right oh that's a + + + align:start position:0% +you get this thing right oh that's a +beautiful molecular orbital between okay + + align:start position:0% +beautiful molecular orbital between okay + + + align:start position:0% +beautiful molecular orbital between okay +fine it was a 1s and a and a 3p but you + + align:start position:0% +fine it was a 1s and a and a 3p but you + + + align:start position:0% +fine it was a 1s and a and a 3p but you +get the point it was a p oriented along + + align:start position:0% +get the point it was a p oriented along + + + align:start position:0% +get the point it was a p oriented along +the axis with Sigma symmetry that means + + align:start position:0% +the axis with Sigma symmetry that means + + + align:start position:0% +the axis with Sigma symmetry that means +if I look along the axis sorry + + align:start position:0% +if I look along the axis sorry + + + align:start position:0% +if I look along the axis sorry +cylindrical symmetry Sigma means if I + + align:start position:0% +cylindrical symmetry Sigma means if I + + + align:start position:0% +cylindrical symmetry Sigma means if I +look around the axis everything's the + + align:start position:0% +look around the axis everything's the + + + align:start position:0% +look around the axis everything's the +same in a circle + + align:start position:0% +same in a circle + + + align:start position:0% +same in a circle +right right so but and so that's a nice + + align:start position:0% +right right so but and so that's a nice + + + align:start position:0% +right right so but and so that's a nice +Sigma orbital between two different + + align:start position:0% +Sigma orbital between two different + + + align:start position:0% +Sigma orbital between two different +atoms M Mo Theory but see the other + + align:start position:0% +atoms M Mo Theory but see the other + + + align:start position:0% +atoms M Mo Theory but see the other +thing that can happen that is something + + align:start position:0% +thing that can happen that is something + + + align:start position:0% +thing that can happen that is something +that I want you to know today + + align:start position:0% +that I want you to know today + + + align:start position:0% +that I want you to know today +is that orbitals on the exact same atom + + align:start position:0% +is that orbitals on the exact same atom + + + align:start position:0% +is that orbitals on the exact same atom +can also do this they can also do this + + align:start position:0% +can also do this they can also do this + + + align:start position:0% +can also do this they can also do this +they can + + align:start position:0% +they can + + + align:start position:0% +they can +combine to form a new + + align:start position:0% +combine to form a new + + + align:start position:0% +combine to form a new +orbital SP same atom forms an SP orbital + + align:start position:0% +orbital SP same atom forms an SP orbital + + + align:start position:0% +orbital SP same atom forms an SP orbital +it's called a hybrid orbital right so + + align:start position:0% +it's called a hybrid orbital right so + + + align:start position:0% +it's called a hybrid orbital right so +we're going to give a couple of examples + + align:start position:0% +we're going to give a couple of examples + + + align:start position:0% +we're going to give a couple of examples +this is + + align:start position:0% +this is + + + align:start position:0% +this is +hybridization + + align:start position:0% + + + + align:start position:0% + +hybridization and give a CLE couple + + align:start position:0% +hybridization and give a CLE couple + + + align:start position:0% +hybridization and give a CLE couple +examples then my why this matters so + + align:start position:0% +examples then my why this matters so + + + align:start position:0% +examples then my why this matters so +this is when two or + + align:start position:0% + + + + align:start position:0% + +more + + align:start position:0% +more + + + align:start position:0% +more +AOS that are similar in + + align:start position:0% +AOS that are similar in + + + align:start position:0% +AOS that are similar in +energy similar they're not the same but + + align:start position:0% +energy similar they're not the same but + + + align:start position:0% +energy similar they're not the same but +they're close you you know you can't + + align:start position:0% +they're close you you know you can't + + + align:start position:0% +they're close you you know you can't +hybridize if one level's way up here and + + align:start position:0% +hybridize if one level's way up here and + + + align:start position:0% +hybridize if one level's way up here and +the other level's way down there but if + + align:start position:0% +the other level's way down there but if + + + align:start position:0% +the other level's way down there but if +they're close to + + align:start position:0% +they're close to + + + align:start position:0% +they're close to +s2p then those + + align:start position:0% +s2p then those + + + align:start position:0% +s2p then those +orbitals can combine + + align:start position:0% +orbitals can combine + + + align:start position:0% +orbitals can combine +and what they do is they combine to form + + align:start position:0% +and what they do is they combine to form + + + align:start position:0% +and what they do is they combine to form +and this is critical + + align:start position:0% +and this is critical + + + align:start position:0% +and this is critical +sets + + align:start position:0% +sets + + + align:start position:0% +sets +of + + align:start position:0% + + + + align:start position:0% + +equivalent + + align:start position:0% + + + + align:start position:0% + +orbitals properly oriented this is + + align:start position:0% +orbitals properly oriented this is + + + align:start position:0% +orbitals properly oriented this is +really important that's why I'm writing + + align:start position:0% +really important that's why I'm writing + + + align:start position:0% +really important that's why I'm writing +it all out properly not property + + align:start position:0% +it all out properly not property + + + align:start position:0% +it all out properly not property +properly + + align:start position:0% + + + + align:start position:0% + +oriented to form bonds all this this is + + align:start position:0% +oriented to form bonds all this this is + + + align:start position:0% +oriented to form bonds all this this is +such a big a big deal to form + + align:start position:0% +such a big a big deal to form + + + align:start position:0% +such a big a big deal to form +bonds it's the last word there but I did + + align:start position:0% +bonds it's the last word there but I did + + + align:start position:0% +bonds it's the last word there but I did +it all caps to emphasize because that's + + align:start position:0% +it all caps to emphasize because that's + + + align:start position:0% +it all caps to emphasize because that's +what this is all about you see because + + align:start position:0% +what this is all about you see because + + + align:start position:0% +what this is all about you see because +now let's take an + + align:start position:0% +now let's take an + + + align:start position:0% +now let's take an +example I'm going to take an example of + + align:start position:0% + + + + align:start position:0% + +methane who brings what to the party + + align:start position:0% +methane who brings what to the party + + + align:start position:0% +methane who brings what to the party +okay I got H I got four H's H 1 s h 1 s + + align:start position:0% +okay I got H I got four H's H 1 s h 1 s + + + align:start position:0% +okay I got H I got four H's H 1 s h 1 s +h 1 s okay this is definitely getting + + align:start position:0% +h 1 s okay this is definitely getting + + + align:start position:0% +h 1 s okay this is definitely getting +repetitive I'm H + + align:start position:0% +repetitive I'm H + + + align:start position:0% +repetitive I'm H +1s but I did it there they are and they + + align:start position:0% +1s but I did it there they are and they + + + align:start position:0% +1s but I did it there they are and they +come and they're like hey carbon what + + align:start position:0% +come and they're like hey carbon what + + + align:start position:0% +come and they're like hey carbon what +you got and the carbon is like okay hold + + align:start position:0% +you got and the carbon is like okay hold + + + align:start position:0% +you got and the carbon is like okay hold +up I got my 2s that's here and I got my + + align:start position:0% +up I got my 2s that's here and I got my + + + align:start position:0% +up I got my 2s that's here and I got my +all my two PS and what are we to do what + + align:start position:0% +all my two PS and what are we to do what + + + align:start position:0% +all my two PS and what are we to do what +are we to do how can these four + + align:start position:0% +are we to do how can these four + + + align:start position:0% +are we to do how can these four +hydrogens come and bond with the carbon + + align:start position:0% +hydrogens come and bond with the carbon + + + align:start position:0% +hydrogens come and bond with the carbon +given that it looks at least like the + + align:start position:0% +given that it looks at least like the + + + align:start position:0% +given that it looks at least like the +carbon isn't bringing the kind you know + + align:start position:0% +carbon isn't bringing the kind you know + + + align:start position:0% +carbon isn't bringing the kind you know +how is it going to do this and also and + + align:start position:0% +how is it going to do this and also and + + + align:start position:0% +how is it going to do this and also and +this is critical this is why I wrote it + + align:start position:0% +this is critical this is why I wrote it + + + align:start position:0% +this is critical this is why I wrote it +here properly oriented to form bonds you + + align:start position:0% +here properly oriented to form bonds you + + + align:start position:0% +here properly oriented to form bonds you +see because this Taps into what we + + align:start position:0% +see because this Taps into what we + + + align:start position:0% +see because this Taps into what we +learned with + + align:start position:0% +learned with + + + align:start position:0% +learned with +vasper it it does because Vesper says + + align:start position:0% +vasper it it does because Vesper says + + + align:start position:0% +vasper it it does because Vesper says +you got to not repel Oh no you're + + align:start position:0% +you got to not repel Oh no you're + + + align:start position:0% +you got to not repel Oh no you're +repelling but try to minimize it that's + + align:start position:0% +repelling but try to minimize it that's + + + align:start position:0% +repelling but try to minimize it that's +what's at the core of + + align:start position:0% +what's at the core of + + + align:start position:0% +what's at the core of +Vesper so what this system sees is a way + + align:start position:0% +Vesper so what this system sees is a way + + + align:start position:0% +Vesper so what this system sees is a way +out and by we out I mean a we to + + align:start position:0% +out and by we out I mean a we to + + + align:start position:0% +out and by we out I mean a we to +happiness and by a we to happiness I I + + align:start position:0% +happiness and by a we to happiness I I + + + align:start position:0% +happiness and by a we to happiness I I +mean a we to lower energy where all four + + align:start position:0% +mean a we to lower energy where all four + + + align:start position:0% +mean a we to lower energy where all four +of these can bond to the carbon atom if + + align:start position:0% +of these can bond to the carbon atom if + + + align:start position:0% +of these can bond to the carbon atom if +it has four same bonds if it had four + + align:start position:0% +it has four same bonds if it had four + + + align:start position:0% +it has four same bonds if it had four +same bonds then it can Orient them + + align:start position:0% +same bonds then it can Orient them + + + align:start position:0% +same bonds then it can Orient them +tetrahedrally and make Vesper happy + + align:start position:0% +tetrahedrally and make Vesper happy + + + align:start position:0% +tetrahedrally and make Vesper happy +minimize repulsions + + align:start position:0% +minimize repulsions + + + align:start position:0% +minimize repulsions +right and you get your methane molecule + + align:start position:0% +right and you get your methane molecule + + + align:start position:0% +right and you get your methane molecule +so what ends up happening is this carbon + + align:start position:0% +so what ends up happening is this carbon + + + align:start position:0% +so what ends up happening is this carbon +atom says hold up you4 hydrogen's you + + align:start position:0% +atom says hold up you4 hydrogen's you + + + align:start position:0% +atom says hold up you4 hydrogen's you +wait there I'm just going to go into the + + align:start position:0% +wait there I'm just going to go into the + + + align:start position:0% +wait there I'm just going to go into the +back and do a little + + align:start position:0% +back and do a little + + + align:start position:0% +back and do a little +reorganization and I'm going to come in + + align:start position:0% +reorganization and I'm going to come in + + + align:start position:0% +reorganization and I'm going to come in +it with I'm going to say well if I had + + align:start position:0% +it with I'm going to say well if I had + + + align:start position:0% +it with I'm going to say well if I had +if my carbon + + align:start position:0% +if my carbon + + + align:start position:0% +if my carbon +atom comes at comes at it with four + + align:start position:0% +atom comes at comes at it with four + + + align:start position:0% +atom comes at comes at it with four +equal orbitals that look like this + + align:start position:0% + + + + align:start position:0% + +those are called + + align:start position:0% +those are called + + + align:start position:0% +those are called +sp3 because I took all three p orbitals + + align:start position:0% +sp3 because I took all three p orbitals + + + align:start position:0% +sp3 because I took all three p orbitals +and I mixed them up with my S orbital + + align:start position:0% +and I mixed them up with my S orbital + + + align:start position:0% +and I mixed them up with my S orbital +and I + + align:start position:0% +and I + + + align:start position:0% +and I +formed equivalent + + align:start position:0% +formed equivalent + + + align:start position:0% +formed equivalent +orbitals now carbon comes out of the + + align:start position:0% +orbitals now carbon comes out of the + + + align:start position:0% +orbitals now carbon comes out of the +back room and it's like hydrogens I'm + + align:start position:0% +back room and it's like hydrogens I'm + + + align:start position:0% +back room and it's like hydrogens I'm +ready I can make a a minimum energy V + + align:start position:0% +ready I can make a a minimum energy V + + + align:start position:0% +ready I can make a a minimum energy V +and and I can follow Vesper and we can + + align:start position:0% +and and I can follow Vesper and we can + + + align:start position:0% +and and I can follow Vesper and we can +have all have very very low energy + + align:start position:0% +have all have very very low energy + + + align:start position:0% +have all have very very low energy +compared to whatever else I could have + + align:start position:0% +compared to whatever else I could have + + + align:start position:0% +compared to whatever else I could have +done if I stuck like + + align:start position:0% +done if I stuck like + + + align:start position:0% +done if I stuck like +that what I'm really talking about okay + + align:start position:0% +that what I'm really talking about okay + + + align:start position:0% +that what I'm really talking about okay +you might know Carbon you know it + + align:start position:0% +you might know Carbon you know it + + + align:start position:0% +you might know Carbon you know it +doesn't go into the back room it doesn't + + align:start position:0% +doesn't go into the back room it doesn't + + + align:start position:0% +doesn't go into the back room it doesn't +but what is it doing it's nothing more + + align:start position:0% +but what is it doing it's nothing more + + + align:start position:0% +but what is it doing it's nothing more +than solving its fringer equation that's + + align:start position:0% +than solving its fringer equation that's + + + align:start position:0% +than solving its fringer equation that's +what this is all about you just changed + + align:start position:0% +what this is all about you just changed + + + align:start position:0% +what this is all about you just changed +the boundary conditions you and so what + + align:start position:0% +the boundary conditions you and so what + + + align:start position:0% +the boundary conditions you and so what +happened that's all hybridization is + + align:start position:0% +happened that's all hybridization is + + + align:start position:0% +happened that's all hybridization is +you're solving the Shar equation all the + + align:start position:0% +you're solving the Shar equation all the + + + align:start position:0% +you're solving the Shar equation all the +time we are always solving the sh + + align:start position:0% +time we are always solving the sh + + + align:start position:0% +time we are always solving the sh +equation all the time and in this case + + align:start position:0% +equation all the time and in this case + + + align:start position:0% +equation all the time and in this case +carbon said well how can I solve it and + + align:start position:0% +carbon said well how can I solve it and + + + align:start position:0% +carbon said well how can I solve it and +minimize my energy with the four + + align:start position:0% +minimize my energy with the four + + + align:start position:0% +minimize my energy with the four +hydrogens this gives you the lowest + + align:start position:0% +hydrogens this gives you the lowest + + + align:start position:0% +hydrogens this gives you the lowest +energy because + + align:start position:0% +energy because + + + align:start position:0% +energy because +now oh I got a movie now I can make + + align:start position:0% +now oh I got a movie now I can make + + + align:start position:0% +now oh I got a movie now I can make +those see so I have a I have a picture + + align:start position:0% +those see so I have a I have a picture + + + align:start position:0% +those see so I have a I have a picture +here s and those three and it says how + + align:start position:0% +here s and those three and it says how + + + align:start position:0% +here s and those three and it says how +can I do it and minimize repulsions this + + align:start position:0% +can I do it and minimize repulsions this + + + align:start position:0% +can I do it and minimize repulsions this +is how three equivalent four equivalent + + align:start position:0% +is how three equivalent four equivalent + + + align:start position:0% +is how three equivalent four equivalent +orbitals to make it sp3 and this is + + align:start position:0% +orbitals to make it sp3 and this is + + + align:start position:0% +orbitals to make it sp3 and this is +where I think a movie helps I'm going to + + align:start position:0% +where I think a movie helps I'm going to + + + align:start position:0% +where I think a movie helps I'm going to +play this it's like a + + align:start position:0% + + + + align:start position:0% + +longal is a shap converging at the + + align:start position:0% +longal is a shap converging at the + + + align:start position:0% +longal is a shap converging at the +nucleus there's the two s so there are + + align:start position:0% +nucleus there's the two s so there are + + + align:start position:0% +nucleus there's the two s so there are +the three 2p orbitals however when + + align:start position:0% +the three 2p orbitals however when + + + align:start position:0% +the three 2p orbitals however when +hybridization occurs the S and P + + align:start position:0% +hybridization occurs the S and P + + + align:start position:0% +hybridization occurs the S and P +orbitals cease to exist they don't cease + + align:start position:0% +orbitals cease to exist they don't cease + + + align:start position:0% +orbitals cease to exist they don't cease +to exist that they just didn't ex it's a + + align:start position:0% +to exist that they just didn't ex it's a + + + align:start position:0% +to exist that they just didn't ex it's a +new boundary condition you're solving + + align:start position:0% +new boundary condition you're solving + + + align:start position:0% +new boundary condition you're solving +the equation right so just to keep that + + align:start position:0% +the equation right so just to keep that + + + align:start position:0% +the equation right so just to keep that +straight right and the two sp3 orbitals + + align:start position:0% +straight right and the two sp3 orbitals + + + align:start position:0% +straight right and the two sp3 orbitals +have an entire different shape that's + + align:start position:0% +have an entire different shape that's + + + align:start position:0% +have an entire different shape that's +true we can see that orbital + + align:start position:0% +true we can see that orbital + + + align:start position:0% +true we can see that orbital +hybridization explains the vcpr + + align:start position:0% +hybridization explains the vcpr + + + align:start position:0% +hybridization explains the vcpr +placement of carbon's four veence + + align:start position:0% +placement of carbon's four veence + + + align:start position:0% +placement of carbon's four veence +electrons since all four 2sp3 orbitals + + align:start position:0% +electrons since all four 2sp3 orbitals + + + align:start position:0% +electrons since all four 2sp3 orbitals +are equivalent each 2sp3 orbital repels + + align:start position:0% +are equivalent each 2sp3 orbital repels + + + align:start position:0% +are equivalent each 2sp3 orbital repels +the others with equal force resulting in + + align:start position:0% +the others with equal force resulting in + + + align:start position:0% +the others with equal force resulting in +identical Bond + + align:start position:0% + + + + align:start position:0% + +angles the carbon atom only hybridizes + + align:start position:0% +angles the carbon atom only hybridizes + + + align:start position:0% +angles the carbon atom only hybridizes +when it is in a bonding situation here + + align:start position:0% +when it is in a bonding situation here + + + align:start position:0% +when it is in a bonding situation here +four hydrogen atoms bond to carbon by + + align:start position:0% +four hydrogen atoms bond to carbon by + + + align:start position:0% +four hydrogen atoms bond to carbon by +overlapping their or orbitals with + + align:start position:0% +overlapping their or orbitals with + + + align:start position:0% +overlapping their or orbitals with +carbon's hybrid + + align:start position:0% +carbon's hybrid + + + align:start position:0% +carbon's hybrid +orbitals so what would be the reason for + + align:start position:0% +orbitals so what would be the reason for + + + align:start position:0% +orbitals so what would be the reason for +this if we go back and see that both + + align:start position:0% +this if we go back and see that both + + + align:start position:0% +this if we go back and see that both +carbon and hydrogen have unpaired + + align:start position:0% +carbon and hydrogen have unpaired + + + align:start position:0% +carbon and hydrogen have unpaired +electrons the overlap allows the + + align:start position:0% +electrons the overlap allows the + + + align:start position:0% +electrons the overlap allows the +electrons to pair and thus go to a lower + + align:start position:0% +electrons to pair and thus go to a lower + + + align:start position:0% +electrons to pair and thus go to a lower +potential energy oh that's such a + + align:start position:0% +potential energy oh that's such a + + + align:start position:0% +potential energy oh that's such a +beautiful place to stop lower potential + + align:start position:0% +beautiful place to stop lower potential + + + align:start position:0% +beautiful place to stop lower potential +energy + + align:start position:0% +energy + + + align:start position:0% +energy +happier that's what this is all about + + align:start position:0% +happier that's what this is all about + + + align:start position:0% +happier that's what this is all about +okay so I I you know like I said you can + + align:start position:0% +okay so I I you know like I said you can + + + align:start position:0% +okay so I I you know like I said you can +see now the difference right if you just + + align:start position:0% +see now the difference right if you just + + + align:start position:0% +see now the difference right if you just +watch is one minute long and I think it + + align:start position:0% +watch is one minute long and I think it + + + align:start position:0% +watch is one minute long and I think it +really brings it to life so if you if + + align:start position:0% +really brings it to life so if you if + + + align:start position:0% +really brings it to life so if you if +you're again want to see this a little + + align:start position:0% +you're again want to see this a little + + + align:start position:0% +you're again want to see this a little +bit more conceptually these movies are + + align:start position:0% +bit more conceptually these movies are + + + align:start position:0% +bit more conceptually these movies are +good I have one more uh movie I'll show + + align:start position:0% +good I have one more uh movie I'll show + + + align:start position:0% +good I have one more uh movie I'll show +you that's like a minute long um okay + + align:start position:0% +you that's like a minute long um okay + + + align:start position:0% +you that's like a minute long um okay +now the thing is so what we just did is + + align:start position:0% +now the thing is so what we just did is + + + align:start position:0% +now the thing is so what we just did is +we did carbon hybridizes to sp3 it's + + align:start position:0% +we did carbon hybridizes to sp3 it's + + + align:start position:0% +we did carbon hybridizes to sp3 it's +called sp3 because you're bringing three + + align:start position:0% +called sp3 because you're bringing three + + + align:start position:0% +called sp3 because you're bringing three +p orbitals and mixing them with s to + + align:start position:0% +p orbitals and mixing them with s to + + + align:start position:0% +p orbitals and mixing them with s to +form four and that allowed it to do this + + align:start position:0% +form four and that allowed it to do this + + + align:start position:0% +form four and that allowed it to do this +but you see if I had ethane which is + + align:start position:0% +but you see if I had ethane which is + + + align:start position:0% +but you see if I had ethane which is +c2h6 it's the same thing now because + + align:start position:0% +c2h6 it's the same thing now because + + + align:start position:0% +c2h6 it's the same thing now because +basically what's happening a carbon atom + + align:start position:0% +basically what's happening a carbon atom + + + align:start position:0% +basically what's happening a carbon atom +comes into the system of ethane and it + + align:start position:0% +comes into the system of ethane and it + + + align:start position:0% +comes into the system of ethane and it +says I need four bonds that are kind of + + align:start position:0% +says I need four bonds that are kind of + + + align:start position:0% +says I need four bonds that are kind of +you know equivalent is all right I got + + align:start position:0% +you know equivalent is all right I got + + + align:start position:0% +you know equivalent is all right I got +to give one to each hydrogen and I got + + align:start position:0% +to give one to each hydrogen and I got + + + align:start position:0% +to give one to each hydrogen and I got +to give one to that other carbon over + + align:start position:0% +to give one to that other carbon over + + + align:start position:0% +to give one to that other carbon over +there and by doing that it can minimize + + align:start position:0% +there and by doing that it can minimize + + + align:start position:0% +there and by doing that it can minimize +its energy it can minimize repulsions it + + align:start position:0% +its energy it can minimize repulsions it + + + align:start position:0% +its energy it can minimize repulsions it +can be the happiest molecule it can be + + align:start position:0% +can be the happiest molecule it can be + + + align:start position:0% +can be the happiest molecule it can be +but to do that carbon must have these + + align:start position:0% +but to do that carbon must have these + + + align:start position:0% +but to do that carbon must have these +four equivalent Sigma like bonds it must + + align:start position:0% +four equivalent Sigma like bonds it must + + + align:start position:0% +four equivalent Sigma like bonds it must +be able to form those four equivalent so + + align:start position:0% +be able to form those four equivalent so + + + align:start position:0% +be able to form those four equivalent so +so that's very similar to methane except + + align:start position:0% +so that's very similar to methane except + + + align:start position:0% +so that's very similar to methane except +that in this so also ethane will be sp3 + + align:start position:0% +that in this so also ethane will be sp3 + + + align:start position:0% +that in this so also ethane will be sp3 +hybridized it will have sp3 hybridized + + align:start position:0% +hybridized it will have sp3 hybridized + + + align:start position:0% +hybridized it will have sp3 hybridized +orbitals but then and you know it's + + align:start position:0% +orbitals but then and you know it's + + + align:start position:0% +orbitals but then and you know it's +coming right so ethane has C2 H6 but + + align:start position:0% +coming right so ethane has C2 H6 but + + + align:start position:0% +coming right so ethane has C2 H6 but +what if + + align:start position:0% +what if + + + align:start position:0% +what if +now I've got ethylene I think I have + + align:start position:0% +now I've got ethylene I think I have + + + align:start position:0% +now I've got ethylene I think I have +maybe I have a picture of it do I have a + + align:start position:0% +maybe I have a picture of it do I have a + + + align:start position:0% +maybe I have a picture of it do I have a +picture of it yeah oh there it is + + align:start position:0% +picture of it yeah oh there it is + + + align:start position:0% +picture of it yeah oh there it is +ethylene ethylene is used this this tiny + + align:start position:0% +ethylene ethylene is used this this tiny + + + align:start position:0% +ethylene ethylene is used this this tiny +molecule with two carbons and four + + align:start position:0% +molecule with two carbons and four + + + align:start position:0% +molecule with two carbons and four +hydrogens instead of six this is used in + + align:start position:0% +hydrogens instead of six this is used in + + + align:start position:0% +hydrogens instead of six this is used in +so many applications I can't possibly + + align:start position:0% +so many applications I can't possibly + + + align:start position:0% +so many applications I can't possibly +list them it polyethylene is a polymer + + align:start position:0% +list them it polyethylene is a polymer + + + align:start position:0% +list them it polyethylene is a polymer +made out of this as a base we will + + align:start position:0% +made out of this as a base we will + + + align:start position:0% +made out of this as a base we will +polymerize this a little bit later in + + align:start position:0% +polymerize this a little bit later in + + + align:start position:0% +polymerize this a little bit later in +the semester when we talk about polymers + + align:start position:0% +the semester when we talk about polymers + + + align:start position:0% +the semester when we talk about polymers +it's also used in the back of your + + align:start position:0% +it's also used in the back of your + + + align:start position:0% +it's also used in the back of your +supermarket in case you didn't know that + + align:start position:0% +supermarket in case you didn't know that + + + align:start position:0% +supermarket in case you didn't know that +very soon actually kind of almost nowish + + align:start position:0% +very soon actually kind of almost nowish + + + align:start position:0% +very soon actually kind of almost nowish +most of the fruit we get will be super + + align:start position:0% +most of the fruit we get will be super + + + align:start position:0% +most of the fruit we get will be super +green when it gets here and then they + + align:start position:0% +green when it gets here and then they + + + align:start position:0% +green when it gets here and then they +use ethylene to actually induce uh uh + + align:start position:0% +use ethylene to actually induce uh uh + + + align:start position:0% +use ethylene to actually induce uh uh +sadly the ripeness doesn't taste as good + + align:start position:0% +sadly the ripeness doesn't taste as good + + + align:start position:0% +sadly the ripeness doesn't taste as good +but anyway okay now but for + + align:start position:0% +but anyway okay now but for + + + align:start position:0% +but anyway okay now but for +ethylene you've got a different + + align:start position:0% +ethylene you've got a different + + + align:start position:0% +ethylene you've got a different +situation because for ethylene each + + align:start position:0% +situation because for ethylene each + + + align:start position:0% +situation because for ethylene each +carbon atom needs three bonds + + align:start position:0% +carbon atom needs three bonds + + + align:start position:0% +carbon atom needs three bonds +each carbon + + align:start position:0% + + + + align:start position:0% + +atom needs three equivalent + + align:start position:0% + + + + align:start position:0% + +bonds and it can do that too so so for + + align:start position:0% + + + + align:start position:0% + +c2h4 each carbon atom needs three + + align:start position:0% +c2h4 each carbon atom needs three + + + align:start position:0% +c2h4 each carbon atom needs three +equivalent bonds and it can do that if + + align:start position:0% +equivalent bonds and it can do that if + + + align:start position:0% +equivalent bonds and it can do that if +it hybridizes in the SP2 hybridization + + align:start position:0% +it hybridizes in the SP2 hybridization + + + align:start position:0% +it hybridizes in the SP2 hybridization +so let's draw that right so these are + + align:start position:0% +so let's draw that right so these are + + + align:start position:0% +so let's draw that right so these are +the original orbitals of carbon and they + + align:start position:0% +the original orbitals of carbon and they + + + align:start position:0% +the original orbitals of carbon and they +will go + + align:start position:0% +will go + + + align:start position:0% +will go +to three SP2 + + align:start position:0% +to three SP2 + + + align:start position:0% +to three SP2 +orbitals notice I can put one electron + + align:start position:0% +orbitals notice I can put one electron + + + align:start position:0% +orbitals notice I can put one electron +in each ready for action ready for + + align:start position:0% +in each ready for action ready for + + + align:start position:0% +in each ready for action ready for +bonding one electron in each of these + + align:start position:0% +bonding one electron in each of these + + + align:start position:0% +bonding one electron in each of these +equivalent hybrid orbitals SP2 and I've + + align:start position:0% +equivalent hybrid orbitals SP2 and I've + + + align:start position:0% +equivalent hybrid orbitals SP2 and I've +got one left over oh ho oh one left + + align:start position:0% +got one left over oh ho oh one left + + + align:start position:0% +got one left over oh ho oh one left +over but you the one left over is a p + + align:start position:0% +over but you the one left over is a p + + + align:start position:0% +over but you the one left over is a p +orbital that didn't get in on the + + align:start position:0% +orbital that didn't get in on the + + + align:start position:0% +orbital that didn't get in on the +hybridization but that's + + align:start position:0% +hybridization but that's + + + align:start position:0% +hybridization but that's +okay that's okay these are P right so + + align:start position:0% +okay that's okay these are P right so + + + align:start position:0% +okay that's okay these are P right so +this is s and this is p 2s 2 2 p and + + align:start position:0% +this is s and this is p 2s 2 2 p and + + + align:start position:0% +this is s and this is p 2s 2 2 p and +that's a p orbital right there those are + + align:start position:0% +that's a p orbital right there those are + + + align:start position:0% +that's a p orbital right there those are +my hybrids and that's a 2p orbital um + + align:start position:0% +my hybrids and that's a 2p orbital um + + + align:start position:0% +my hybrids and that's a 2p orbital um +this is there's another 2p orbital on + + align:start position:0% +this is there's another 2p orbital on + + + align:start position:0% +this is there's another 2p orbital on +the other carbon also got left out now I + + align:start position:0% +the other carbon also got left out now I + + + align:start position:0% +the other carbon also got left out now I +only needed three because you see I form + + align:start position:0% +only needed three because you see I form + + + align:start position:0% +only needed three because you see I form +this nice spatially maximized to + + align:start position:0% +this nice spatially maximized to + + + align:start position:0% +this nice spatially maximized to +minimize repulsion right separation + + align:start position:0% +minimize repulsion right separation + + + align:start position:0% +minimize repulsion right separation +maximized to minimize repulsion so it's + + align:start position:0% +maximized to minimize repulsion so it's + + + align:start position:0% +maximized to minimize repulsion so it's +a planer oh but it's planer for another + + align:start position:0% +a planer oh but it's planer for another + + + align:start position:0% +a planer oh but it's planer for another +reason because each of these carbon + + align:start position:0% +reason because each of these carbon + + + align:start position:0% +reason because each of these carbon +atoms has a p orbital and we know that + + align:start position:0% +atoms has a p orbital and we know that + + + align:start position:0% +atoms has a p orbital and we know that +2p orbitals can form a pi Bond right and + + align:start position:0% +2p orbitals can form a pi Bond right and + + + align:start position:0% +2p orbitals can form a pi Bond right and +I have a picture of that that's exactly + + align:start position:0% +I have a picture of that that's exactly + + + align:start position:0% +I have a picture of that that's exactly +what they do so so this is the + + align:start position:0% +what they do so so this is the + + + align:start position:0% +what they do so so this is the +sigma the hybrid orbitals are Sigma + + align:start position:0% +sigma the hybrid orbitals are Sigma + + + align:start position:0% +sigma the hybrid orbitals are Sigma +right because they're along the axis and + + align:start position:0% +right because they're along the axis and + + + align:start position:0% +right because they're along the axis and +look at them if I look down this axis I + + align:start position:0% +look at them if I look down this axis I + + + align:start position:0% +look at them if I look down this axis I +can draw a circle and there's full + + align:start position:0% +can draw a circle and there's full + + + align:start position:0% +can draw a circle and there's full +cylindrical symmetry right but I've got + + align:start position:0% +cylindrical symmetry right but I've got + + + align:start position:0% +cylindrical symmetry right but I've got +this left over p orbital here on each + + align:start position:0% +this left over p orbital here on each + + + align:start position:0% +this left over p orbital here on each +carbon atom that's that one there and + + align:start position:0% +carbon atom that's that one there and + + + align:start position:0% +carbon atom that's that one there and +and I didn't need it to do this but it's + + align:start position:0% +and I didn't need it to do this but it's + + + align:start position:0% +and I didn't need it to do this but it's +still there and so it forms a bond it + + align:start position:0% +still there and so it forms a bond it + + + align:start position:0% +still there and so it forms a bond it +forms a bond right it forms a pi + + align:start position:0% +forms a bond right it forms a pi + + + align:start position:0% +forms a bond right it forms a pi +Bond so that P + + align:start position:0% +Bond so that P + + + align:start position:0% +Bond so that P +with the p from the other one forms a pi + + align:start position:0% +with the p from the other one forms a pi + + + align:start position:0% +with the p from the other one forms a pi +and a pi Star right in Theos and you you + + align:start position:0% +and a pi Star right in Theos and you you + + + align:start position:0% +and a pi Star right in Theos and you you +occupy the pi with the two electrons and + + align:start position:0% +occupy the pi with the two electrons and + + + align:start position:0% +occupy the pi with the two electrons and +that's a + + align:start position:0% +that's a + + + align:start position:0% +that's a +bond so so in this you've got uh you've + + align:start position:0% +bond so so in this you've got uh you've + + + align:start position:0% +bond so so in this you've got uh you've +got a bond from this uh that's above or + + align:start position:0% +got a bond from this uh that's above or + + + align:start position:0% +got a bond from this uh that's above or +below in in you know in this orientation + + align:start position:0% +below in in you know in this orientation + + + align:start position:0% +below in in you know in this orientation +it's above or below the plane and you've + + align:start position:0% +it's above or below the plane and you've + + + align:start position:0% +it's above or below the plane and you've +got a bond from this so you've got a + + align:start position:0% +got a bond from this so you've got a + + + align:start position:0% +got a bond from this so you've got a +double bond that's exactly what we know + + align:start position:0% +double bond that's exactly what we know + + + align:start position:0% +double bond that's exactly what we know +already but we know so much more now we + + align:start position:0% +already but we know so much more now we + + + align:start position:0% +already but we know so much more now we +know so much more because because now we + + align:start position:0% +know so much more because because now we + + + align:start position:0% +know so much more because because now we +know that it's not just two you know two + + align:start position:0% +know that it's not just two you know two + + + align:start position:0% +know that it's not just two you know two +bonds and four electrons we know that + + align:start position:0% +bonds and four electrons we know that + + + align:start position:0% +bonds and four electrons we know that +they have shape to them we know that + + align:start position:0% +they have shape to them we know that + + + align:start position:0% +they have shape to them we know that +they have structure to them and we know + + align:start position:0% +they have structure to them and we know + + + align:start position:0% +they have structure to them and we know +that those bonds are + + align:start position:0% +that those bonds are + + + align:start position:0% +that those bonds are +different these are Pi bonds and that's + + align:start position:0% +different these are Pi bonds and that's + + + align:start position:0% +different these are Pi bonds and that's +a sigma Bond right and you also know why + + align:start position:0% +a sigma Bond right and you also know why + + + align:start position:0% +a sigma Bond right and you also know why +this molecule stays planer because if I + + align:start position:0% +this molecule stays planer because if I + + + align:start position:0% +this molecule stays planer because if I +try to twist it then those P orbitals + + align:start position:0% +try to twist it then those P orbitals + + + align:start position:0% +try to twist it then those P orbitals +won't align right it's like a little + + align:start position:0% +won't align right it's like a little + + + align:start position:0% +won't align right it's like a little +spring if I if I try to twist it it's + + align:start position:0% +spring if I if I try to twist it it's + + + align:start position:0% +spring if I if I try to twist it it's +going to go right back because it's + + align:start position:0% +going to go right back because it's + + + align:start position:0% +going to go right back because it's +minimum in energy is when these things + + align:start position:0% +minimum in energy is when these things + + + align:start position:0% +minimum in energy is when these things +can maximize their overlap right so + + align:start position:0% +can maximize their overlap right so + + + align:start position:0% +can maximize their overlap right so +that's going to stay + + align:start position:0% +that's going to stay + + + align:start position:0% +that's going to stay +planer + + align:start position:0% +planer + + + align:start position:0% +planer +okay now and so so for this case you've + + align:start position:0% +okay now and so so for this case you've + + + align:start position:0% +okay now and so so for this case you've +got a double + + align:start position:0% +got a double + + + align:start position:0% +got a double +bond so this is + + align:start position:0% +bond so this is + + + align:start position:0% +bond so this is +uh double bond and I think I have a + + align:start position:0% +uh double bond and I think I have a + + + align:start position:0% +uh double bond and I think I have a +little carbon carbon double bond and I + + align:start position:0% +little carbon carbon double bond and I + + + align:start position:0% +little carbon carbon double bond and I +think I've got a video to show this cuz + + align:start position:0% +think I've got a video to show this cuz + + + align:start position:0% +think I've got a video to show this cuz +I I this is another case where you know + + align:start position:0% +I I this is another case where you know + + + align:start position:0% +I I this is another case where you know +again I just want to make sure you guys + + align:start position:0% +again I just want to make sure you guys + + + align:start position:0% +again I just want to make sure you guys +get the intuition here and I thought + + align:start position:0% +get the intuition here and I thought + + + align:start position:0% +get the intuition here and I thought +this was a pretty cool animation of SP2 + + align:start position:0% +this was a pretty cool animation of SP2 + + + align:start position:0% +this was a pretty cool animation of SP2 +so I'll play it for a minute b 1 2s and + + align:start position:0% +so I'll play it for a minute b 1 2s and + + + align:start position:0% +so I'll play it for a minute b 1 2s and +two of the 2p orbitals hybridize + + align:start position:0% +two of the 2p orbitals hybridize + + + align:start position:0% +two of the 2p orbitals hybridize +consequently this hybridization is + + align:start position:0% +consequently this hybridization is + + + align:start position:0% +consequently this hybridization is +termed as SP2 hybridization look at that + + align:start position:0% +termed as SP2 hybridization look at that + + + align:start position:0% +termed as SP2 hybridization look at that +the hybridization leads to the formation + + align:start position:0% +the hybridization leads to the formation + + + align:start position:0% +the hybridization leads to the formation +of three equ energic SP2 hybrid + + align:start position:0% + + + + align:start position:0% + +orbitals as you can see each SP2 hybrid + + align:start position:0% +orbitals as you can see each SP2 hybrid + + + align:start position:0% +orbitals as you can see each SP2 hybrid +orbital is bilobed one loob bigger than + + align:start position:0% +orbital is bilobed one loob bigger than + + + align:start position:0% +orbital is bilobed one loob bigger than +the other the half filled p orbital + + align:start position:0% +the other the half filled p orbital + + + align:start position:0% +the other the half filled p orbital +which was not involved in + + align:start position:0% +which was not involved in + + + align:start position:0% +which was not involved in +hybridization lies at right angles to + + align:start position:0% +hybridization lies at right angles to + + + align:start position:0% +hybridization lies at right angles to +the plane of the equilateral + + align:start position:0% +the plane of the equilateral + + + align:start position:0% +the plane of the equilateral +triangle now let us understand how this + + align:start position:0% +triangle now let us understand how this + + + align:start position:0% +triangle now let us understand how this +hybridized state results in the + + align:start position:0% +hybridized state results in the + + + align:start position:0% +hybridized state results in the +formation of a double + + align:start position:0% +formation of a double + + + align:start position:0% +formation of a double +bond for this imagine a similar SP2 + + align:start position:0% +bond for this imagine a similar SP2 + + + align:start position:0% +bond for this imagine a similar SP2 +hybridized carbon atom approaching this + + align:start position:0% +hybridized carbon atom approaching this + + + align:start position:0% +hybridized carbon atom approaching this +carbon atom + + align:start position:0% +carbon atom + + + align:start position:0% +carbon atom +as these atoms come closer an orbital + + align:start position:0% +as these atoms come closer an orbital + + + align:start position:0% +as these atoms come closer an orbital +overlap takes place along the inter + + align:start position:0% +overlap takes place along the inter + + + align:start position:0% +overlap takes place along the inter +nuclear axis this bond is called a sigma + + align:start position:0% +nuclear axis this bond is called a sigma + + + align:start position:0% +nuclear axis this bond is called a sigma +Bond at this stage the unhybridized P + + align:start position:0% +Bond at this stage the unhybridized P + + + align:start position:0% +Bond at this stage the unhybridized P +orbitals which lie above and below the + + align:start position:0% +orbitals which lie above and below the + + + align:start position:0% +orbitals which lie above and below the +plane of the sigma Bond also come very + + align:start position:0% +plane of the sigma Bond also come very + + + align:start position:0% +plane of the sigma Bond also come very +close to each other and overlap + + align:start position:0% +close to each other and overlap + + + align:start position:0% +close to each other and overlap +laterally resulting in the formation of + + align:start position:0% +laterally resulting in the formation of + + + align:start position:0% +laterally resulting in the formation of +a pi bond between the two carbon atoms + + align:start position:0% +a pi bond between the two carbon atoms + + + align:start position:0% +a pi bond between the two carbon atoms +all right okay so the + + align:start position:0% +all right okay so the + + + align:start position:0% +all right okay so the +thought about it I watched that movie of + + align:start position:0% +thought about it I watched that movie of + + + align:start position:0% +thought about it I watched that movie of +course many times over the weekend and I + + align:start position:0% +course many times over the weekend and I + + + align:start position:0% +course many times over the weekend and I +thought about can I animate you know the + + align:start position:0% +thought about can I animate you know the + + + align:start position:0% +thought about can I animate you know the +electrons like that and do the and I I + + align:start position:0% +electrons like that and do the and I I + + + align:start position:0% +electrons like that and do the and I I +think I could but I don't know that it + + align:start position:0% +think I could but I don't know that it + + + align:start position:0% +think I could but I don't know that it +would be a good use of our time so I + + align:start position:0% +would be a good use of our time so I + + + align:start position:0% +would be a good use of our time so I +thought that they did a pretty good job + + align:start position:0% +thought that they did a pretty good job + + + align:start position:0% +thought that they did a pretty good job +of of bringing it to life now this is a + + align:start position:0% +of of bringing it to life now this is a + + + align:start position:0% +of of bringing it to life now this is a +great time for me uh to tell you about + + align:start position:0% +great time for me uh to tell you about + + + align:start position:0% +great time for me uh to tell you about +my why this matters and of course the + + align:start position:0% +my why this matters and of course the + + + align:start position:0% +my why this matters and of course the +SP2 carbon atom matters because of + + align:start position:0% +SP2 carbon atom matters because of + + + align:start position:0% +SP2 carbon atom matters because of +drinking + + align:start position:0% +drinking + + + align:start position:0% +drinking +water of course + + align:start position:0% +water of course + + + align:start position:0% +water of course +um and you know this is a well in in a + + align:start position:0% +um and you know this is a well in in a + + + align:start position:0% +um and you know this is a well in in a +district in India where more than 50% of + + align:start position:0% +district in India where more than 50% of + + + align:start position:0% +district in India where more than 50% of +the wells exceed The Who limits for + + align:start position:0% +the wells exceed The Who limits for + + + align:start position:0% +the wells exceed The Who limits for +arsenic by around a factor of five um uh + + align:start position:0% +arsenic by around a factor of five um uh + + + align:start position:0% +arsenic by around a factor of five um uh +1.8 billion people in the world drink + + align:start position:0% +1.8 billion people in the world drink + + + align:start position:0% +1.8 billion people in the world drink +Fally contaminated water on a daily + + align:start position:0% +Fally contaminated water on a daily + + + align:start position:0% +Fally contaminated water on a daily +basis 600 million people boil their + + align:start position:0% +basis 600 million people boil their + + + align:start position:0% +basis 600 million people boil their +water in the world um boiling doesn't + + align:start position:0% +water in the world um boiling doesn't + + + align:start position:0% +water in the world um boiling doesn't +help as arsenic though arsenic just + + align:start position:0% +help as arsenic though arsenic just + + + align:start position:0% +help as arsenic though arsenic just +stays in in the boiled water it kills + + align:start position:0% +stays in in the boiled water it kills + + + align:start position:0% +stays in in the boiled water it kills +bacteria but it doesn't help with toxic + + align:start position:0% +bacteria but it doesn't help with toxic + + + align:start position:0% +bacteria but it doesn't help with toxic +uh toxic elements um if you look at the + + align:start position:0% +uh toxic elements um if you look at the + + + align:start position:0% +uh toxic elements um if you look at the +world as a whole and you look at sort of + + align:start position:0% +world as a whole and you look at sort of + + + align:start position:0% +world as a whole and you look at sort of +where there are water uh U you Water + + align:start position:0% +where there are water uh U you Water + + + align:start position:0% +where there are water uh U you Water +Crisis where the Water Crisis is at this + + align:start position:0% +Crisis where the Water Crisis is at this + + + align:start position:0% +Crisis where the Water Crisis is at this +level it's it's a little over three and + + align:start position:0% +level it's it's a little over three and + + + align:start position:0% +level it's it's a little over three and +a half billion people um and in those + + align:start position:0% +a half billion people um and in those + + + align:start position:0% +a half billion people um and in those +countries almost 185 or so countries um + + align:start position:0% +countries almost 185 or so countries um + + + align:start position:0% +countries almost 185 or so countries um +where this is a serious problem if you + + align:start position:0% +where this is a serious problem if you + + + align:start position:0% +where this is a serious problem if you +look at the cause of disease and the + + align:start position:0% +look at the cause of disease and the + + + align:start position:0% +look at the cause of disease and the +cause of death in those count 70 to 80% + + align:start position:0% +cause of death in those count 70 to 80% + + + align:start position:0% +cause of death in those count 70 to 80% +of all disease and almost 30% of all + + align:start position:0% +of all disease and almost 30% of all + + + align:start position:0% +of all disease and almost 30% of all +death can be attributed to the water + + align:start position:0% +death can be attributed to the water + + + align:start position:0% +death can be attributed to the water +quality right so uh when I talk about + + align:start position:0% +quality right so uh when I talk about + + + align:start position:0% +quality right so uh when I talk about +water as a problem I really mean it's a + + align:start position:0% +water as a problem I really mean it's a + + + align:start position:0% +water as a problem I really mean it's a +serious problem it's a problem of life + + align:start position:0% +serious problem it's a problem of life + + + align:start position:0% +serious problem it's a problem of life +or death um now uh this is to get fresh + + align:start position:0% +or death um now uh this is to get fresh + + + align:start position:0% +or death um now uh this is to get fresh +drinking water if you look at the planet + + align:start position:0% +drinking water if you look at the planet + + + align:start position:0% +drinking water if you look at the planet +and you say well where is the water on + + align:start position:0% +and you say well where is the water on + + + align:start position:0% +and you say well where is the water on +this planet where is the water on this + + align:start position:0% +this planet where is the water on this + + + align:start position:0% +this planet where is the water on this +planet I like this picture because um + + align:start position:0% +planet I like this picture because um + + + align:start position:0% +planet I like this picture because um +we consume water volumetrically not in + + align:start position:0% +we consume water volumetrically not in + + + align:start position:0% +we consume water volumetrically not in +an area right we use water as a volume + + align:start position:0% +an area right we use water as a volume + + + align:start position:0% +an area right we use water as a volume +and this is the water we have on this + + align:start position:0% +and this is the water we have on this + + + align:start position:0% +and this is the water we have on this +precious Planet as a + + align:start position:0% +precious Planet as a + + + align:start position:0% +precious Planet as a +volume this bubble here is all of the + + align:start position:0% +volume this bubble here is all of the + + + align:start position:0% +volume this bubble here is all of the +ocean water right it's about 70 it's + + align:start position:0% +ocean water right it's about 70 it's + + + align:start position:0% +ocean water right it's about 70 it's +about 97% of all the water that bubble + + align:start position:0% +about 97% of all the water that bubble + + + align:start position:0% +about 97% of all the water that bubble +there is fresh water that is + + align:start position:0% +there is fresh water that is + + + align:start position:0% +there is fresh water that is +inaccessible right it's frozen and this + + align:start position:0% +inaccessible right it's frozen and this + + + align:start position:0% +inaccessible right it's frozen and this +one here you can't really see it there + + align:start position:0% +one here you can't really see it there + + + align:start position:0% +one here you can't really see it there +is another dot there that's less than 1% + + align:start position:0% +is another dot there that's less than 1% + + + align:start position:0% +is another dot there that's less than 1% +of the world's water that is our + + align:start position:0% +of the world's water that is our + + + align:start position:0% +of the world's water that is our +drinking water ecosystem that is what we + + align:start position:0% +drinking water ecosystem that is what we + + + align:start position:0% +drinking water ecosystem that is what we +are destroying um and but see so what + + align:start position:0% +are destroying um and but see so what + + + align:start position:0% +are destroying um and but see so what +okay so there's a lot of things we can + + align:start position:0% +okay so there's a lot of things we can + + + align:start position:0% +okay so there's a lot of things we can +try to do about this right uh one of the + + align:start position:0% +try to do about this right uh one of the + + + align:start position:0% +try to do about this right uh one of the +things we can try to do is to see if we + + align:start position:0% +things we can try to do is to see if we + + + align:start position:0% +things we can try to do is to see if we +can tap into this in a way that's more + + align:start position:0% +can tap into this in a way that's more + + + align:start position:0% +can tap into this in a way that's more +affordable and more efficient because + + align:start position:0% +affordable and more efficient because + + + align:start position:0% +affordable and more efficient because +there's a lot of water here right and + + align:start position:0% +there's a lot of water here right and + + + align:start position:0% +there's a lot of water here right and +use that um but the problem is if you + + align:start position:0% +use that um but the problem is if you + + + align:start position:0% +use that um but the problem is if you +look at the cost of desalination today + + align:start position:0% +look at the cost of desalination today + + + align:start position:0% +look at the cost of desalination today +as opposed to the C that's if you look + + align:start position:0% +as opposed to the C that's if you look + + + align:start position:0% +as opposed to the C that's if you look +at the cost of that as opposed to just + + align:start position:0% +at the cost of that as opposed to just + + + align:start position:0% +at the cost of that as opposed to just +digging water out of a well like the one + + align:start position:0% +digging water out of a well like the one + + + align:start position:0% +digging water out of a well like the one +I just showed you in India it's over a + + align:start position:0% +I just showed you in India it's over a + + + align:start position:0% +I just showed you in India it's over a +factor of 10 right still and and in fact + + align:start position:0% +factor of 10 right still and and in fact + + + align:start position:0% +factor of 10 right still and and in fact +one of the the big issues with + + align:start position:0% +one of the the big issues with + + + align:start position:0% +one of the the big issues with +desalination isn't just the the total + + align:start position:0% +desalination isn't just the the total + + + align:start position:0% +desalination isn't just the the total +cost or the operating cost but the + + align:start position:0% +cost or the operating cost but the + + + align:start position:0% +cost or the operating cost but the +capital cost how do you build this plant + + align:start position:0% +capital cost how do you build this plant + + + align:start position:0% +capital cost how do you build this plant +in the first place right um and so it + + align:start position:0% +in the first place right um and so it + + + align:start position:0% +in the first place right um and so it +takes too much + + align:start position:0% +takes too much + + + align:start position:0% +takes too much +money if you look at the the thing + + align:start position:0% +money if you look at the the thing + + + align:start position:0% +money if you look at the the thing +that's at the heart of desalination it's + + align:start position:0% +that's at the heart of desalination it's + + + align:start position:0% +that's at the heart of desalination it's +a filter right it's a filter and I + + align:start position:0% +a filter right it's a filter and I + + + align:start position:0% +a filter right it's a filter and I +talked about this in my last why this + + align:start position:0% +talked about this in my last why this + + + align:start position:0% +talked about this in my last why this +matters when I talked about separations + + align:start position:0% +matters when I talked about separations + + + align:start position:0% +matters when I talked about separations +and I promise that in my next why this + + align:start position:0% +and I promise that in my next why this + + + align:start position:0% +and I promise that in my next why this +matter I talk about water right which is + + align:start position:0% +matter I talk about water right which is + + + align:start position:0% +matter I talk about water right which is +what I'm doing um if you look at a + + align:start position:0% +what I'm doing um if you look at a + + + align:start position:0% +what I'm doing um if you look at a +diesel plant this is one of the world's + + align:start position:0% +diesel plant this is one of the world's + + + align:start position:0% +diesel plant this is one of the world's +largest this is a plant called the + + align:start position:0% +largest this is a plant called the + + + align:start position:0% +largest this is a plant called the +hadera plant in Israel um and you look + + align:start position:0% +hadera plant in Israel um and you look + + + align:start position:0% +hadera plant in Israel um and you look +at what their costs are that remember + + align:start position:0% +at what their costs are that remember + + + align:start position:0% +at what their costs are that remember +the cost is half of that cost almost + + align:start position:0% +the cost is half of that cost almost + + + align:start position:0% +the cost is half of that cost almost +half of the cost is in Just Energy and + + align:start position:0% +half of the cost is in Just Energy and + + + align:start position:0% +half of the cost is in Just Energy and +almost all of that energy is in pushing + + align:start position:0% +almost all of that energy is in pushing + + + align:start position:0% +almost all of that energy is in pushing +salt water through a filter through a + + align:start position:0% +salt water through a filter through a + + + align:start position:0% +salt water through a filter through a +membrane + + align:start position:0% +membrane + + + align:start position:0% +membrane +uh that's called a reverse osmosis + + align:start position:0% +uh that's called a reverse osmosis + + + align:start position:0% +uh that's called a reverse osmosis +membrane because you're going against + + align:start position:0% +membrane because you're going against + + + align:start position:0% +membrane because you're going against +the osmotic + + align:start position:0% +the osmotic + + + align:start position:0% +the osmotic +pressure um and if you look at the + + align:start position:0% +pressure um and if you look at the + + + align:start position:0% +pressure um and if you look at the +membrane itself this is a picture of it + + align:start position:0% +membrane itself this is a picture of it + + + align:start position:0% +membrane itself this is a picture of it +it's actually very small layer on top of + + align:start position:0% +it's actually very small layer on top of + + + align:start position:0% +it's actually very small layer on top of +this active layer um that does all the + + align:start position:0% +this active layer um that does all the + + + align:start position:0% +this active layer um that does all the +work it's not a very good design in fact + + align:start position:0% +work it's not a very good design in fact + + + align:start position:0% +work it's not a very good design in fact +membranes for + + align:start position:0% +membranes for + + + align:start position:0% +membranes for +desalination are pretty bad right uh uh + + align:start position:0% +desalination are pretty bad right uh uh + + + align:start position:0% +desalination are pretty bad right uh uh +they kind of do everything worse than + + align:start position:0% +they kind of do everything worse than + + + align:start position:0% +they kind of do everything worse than +they should except that they work which + + align:start position:0% +they should except that they work which + + + align:start position:0% +they should except that they work which +is good and they're cheap dollar square + + align:start position:0% +is good and they're cheap dollar square + + + align:start position:0% +is good and they're cheap dollar square +foot but but see they're very they take + + align:start position:0% +foot but but see they're very they take + + + align:start position:0% +foot but but see they're very they take +much more energy than you + + align:start position:0% +much more energy than you + + + align:start position:0% +much more energy than you +need they foul up very easily and then + + align:start position:0% +need they foul up very easily and then + + + align:start position:0% +need they foul up very easily and then +that means stuff gets kind of you know + + align:start position:0% +that means stuff gets kind of you know + + + align:start position:0% +that means stuff gets kind of you know +stuck in them and then you can't take it + + align:start position:0% +stuck in them and then you can't take it + + + align:start position:0% +stuck in them and then you can't take it +out you can't clean them look these + + align:start position:0% +out you can't clean them look these + + + align:start position:0% +out you can't clean them look these +these polyamide membranes which is the + + align:start position:0% +these polyamide membranes which is the + + + align:start position:0% +these polyamide membranes which is the +same polymer used in these membranes for + + align:start position:0% +same polymer used in these membranes for + + + align:start position:0% +same polymer used in these membranes for +50 years haven't changed the + + align:start position:0% +50 years haven't changed the + + + align:start position:0% +50 years haven't changed the +material those polyamide membranes are + + align:start position:0% +material those polyamide membranes are + + + align:start position:0% +material those polyamide membranes are +destroyed by chlorine so even in a Dell + + align:start position:0% +destroyed by chlorine so even in a Dell + + + align:start position:0% +destroyed by chlorine so even in a Dell +plant in a Dell plant if you have + + align:start position:0% +plant in a Dell plant if you have + + + align:start position:0% +plant in a Dell plant if you have +drinking water in your feed + + align:start position:0% +drinking water in your feed + + + align:start position:0% +drinking water in your feed +stream drinking water has six parts per + + align:start position:0% +stream drinking water has six parts per + + + align:start position:0% +stream drinking water has six parts per +million chlorine that's not much they + + align:start position:0% +million chlorine that's not much they + + + align:start position:0% +million chlorine that's not much they +still will go through the cost to remove + + align:start position:0% +still will go through the cost to remove + + + align:start position:0% +still will go through the cost to remove +it they will remove it from the feed why + + align:start position:0% +it they will remove it from the feed why + + + align:start position:0% +it they will remove it from the feed why +because if you leave that little amount + + align:start position:0% +because if you leave that little amount + + + align:start position:0% +because if you leave that little amount +of chlorine in the feed these membranes + + align:start position:0% +of chlorine in the feed these membranes + + + align:start position:0% +of chlorine in the feed these membranes +get destroyed by the way there's 40,000 + + align:start position:0% +get destroyed by the way there's 40,000 + + + align:start position:0% +get destroyed by the way there's 40,000 +of these membranes in this plant each + + align:start position:0% +of these membranes in this plant each + + + align:start position:0% +of these membranes in this plant each +one is 2 meters long and 40 sare meters + + align:start position:0% +one is 2 meters long and 40 sare meters + + + align:start position:0% +one is 2 meters long and 40 sare meters +of area so so these are so + + align:start position:0% +of area so so these are so + + + align:start position:0% +of area so so these are so +delicate that you can't really clean + + align:start position:0% +delicate that you can't really clean + + + align:start position:0% +delicate that you can't really clean +them well and that's part of what the + + align:start position:0% +them well and that's part of what the + + + align:start position:0% +them well and that's part of what the +cost of a plant involves right that's + + align:start position:0% +cost of a plant involves right that's + + + align:start position:0% +cost of a plant involves right that's +part of what the cost of a plant + + align:start position:0% +part of what the cost of a plant + + + align:start position:0% +part of what the cost of a plant +involves now um this would be like a + + align:start position:0% +involves now um this would be like a + + + align:start position:0% +involves now um this would be like a +plant right you have sea water coming in + + align:start position:0% +plant right you have sea water coming in + + + align:start position:0% +plant right you have sea water coming in +and you know and then you've got your + + align:start position:0% +and you know and then you've got your + + + align:start position:0% +and you know and then you've got your +membrane module that's taking the salt + + align:start position:0% +membrane module that's taking the salt + + + align:start position:0% +membrane module that's taking the salt +out of the water and then the product + + align:start position:0% +out of the water and then the product + + + align:start position:0% +out of the water and then the product +water but because this this filter is so + + align:start position:0% +water but because this this filter is so + + + align:start position:0% +water but because this this filter is so +delicate there's the picture because + + align:start position:0% +delicate there's the picture because + + + align:start position:0% +delicate there's the picture because +that filter is so delicate you actually + + align:start position:0% +that filter is so delicate you actually + + + align:start position:0% +that filter is so delicate you actually +have to add a whole lot more to the + + align:start position:0% +have to add a whole lot more to the + + + align:start position:0% +have to add a whole lot more to the +plant so much of a desel plant is built + + align:start position:0% +plant so much of a desel plant is built + + + align:start position:0% +plant so much of a desel plant is built +around essentially protecting this + + align:start position:0% +around essentially protecting this + + + align:start position:0% +around essentially protecting this +membrane so that's cost that's cost + + align:start position:0% +membrane so that's cost that's cost + + + align:start position:0% +membrane so that's cost that's cost +right a better membrane could change + + align:start position:0% +right a better membrane could change + + + align:start position:0% +right a better membrane could change +this but like I said the membrane oh + + align:start position:0% +this but like I said the membrane oh + + + align:start position:0% +this but like I said the membrane oh +there it is you can't you can't Snapchat + + align:start position:0% +there it is you can't you can't Snapchat + + + align:start position:0% +there it is you can't you can't Snapchat +on + + align:start position:0% +on + + + align:start position:0% +on +that Snapchat what is it that people do + + align:start position:0% +that Snapchat what is it that people do + + + align:start position:0% +that Snapchat what is it that people do +today not Snapchat yeah Snapchat yeah + + align:start position:0% +today not Snapchat yeah Snapchat yeah + + + align:start position:0% +today not Snapchat yeah Snapchat yeah +okay thank you you can't Snapchat on + + align:start position:0% +okay thank you you can't Snapchat on + + + align:start position:0% +okay thank you you can't Snapchat on +that that's what I + + align:start position:0% +that that's what I + + + align:start position:0% +that that's what I +meant I know it's not my space but I + + align:start position:0% +meant I know it's not my space but I + + + align:start position:0% +meant I know it's not my space but I +don't know but anyway um uh this is like + + align:start position:0% +don't know but anyway um uh this is like + + + align:start position:0% +don't know but anyway um uh this is like +you know when I look at at at at + + align:start position:0% +you know when I look at at at at + + + align:start position:0% +you know when I look at at at at +membranes today as a material SCI + + align:start position:0% +membranes today as a material SCI + + + align:start position:0% +membranes today as a material SCI +science is materials chemist all the + + align:start position:0% +science is materials chemist all the + + + align:start position:0% +science is materials chemist all the +memb is I think that's what it looks + + align:start position:0% +memb is I think that's what it looks + + + align:start position:0% +memb is I think that's what it looks +like why doesn't have to be the case we + + align:start position:0% +like why doesn't have to be the case we + + + align:start position:0% +like why doesn't have to be the case we +can do so much + + align:start position:0% +can do so much + + + align:start position:0% +can do so much +better and and so okay energy and cost + + align:start position:0% +better and and so okay energy and cost + + + align:start position:0% +better and and so okay energy and cost +goes into pre-treatment secondary + + align:start position:0% +goes into pre-treatment secondary + + + align:start position:0% +goes into pre-treatment secondary +treatment and this is where this comes + + align:start position:0% +treatment and this is where this comes + + + align:start position:0% +treatment and this is where this comes +back this beautiful + + align:start position:0% +back this beautiful + + + align:start position:0% +back this beautiful +material that we have now understood + + align:start position:0% +material that we have now understood + + + align:start position:0% +material that we have now understood +more than we did before because remember + + align:start position:0% +more than we did before because remember + + + align:start position:0% +more than we did before because remember +before I showed you graphine and I + + align:start position:0% +before I showed you graphine and I + + + align:start position:0% +before I showed you graphine and I +showed you no I showed you + + align:start position:0% +showed you no I showed you + + + align:start position:0% +showed you no I showed you +Benzene and we talked about it as a + + align:start position:0% +Benzene and we talked about it as a + + + align:start position:0% +Benzene and we talked about it as a +Lewis resonance structure remember right + + align:start position:0% +Lewis resonance structure remember right + + + align:start position:0% +Lewis resonance structure remember right +a leis resonance structure to help + + align:start position:0% +a leis resonance structure to help + + + align:start position:0% +a leis resonance structure to help +explain how it LO you know gra graphing + + align:start position:0% +explain how it LO you know gra graphing + + + align:start position:0% +explain how it LO you know gra graphing +does not have alternating bonds remember + + align:start position:0% +does not have alternating bonds remember + + + align:start position:0% +does not have alternating bonds remember +that's what we talked about before it's + + align:start position:0% +that's what we talked about before it's + + + align:start position:0% +that's what we talked about before it's +a Lewis resonant + + align:start position:0% +a Lewis resonant + + + align:start position:0% +a Lewis resonant +structure so it lowers its energy by + + align:start position:0% +structure so it lowers its energy by + + + align:start position:0% +structure so it lowers its energy by +having two sets of structures that have + + align:start position:0% +having two sets of structures that have + + + align:start position:0% +having two sets of structures that have +sort of alternating bonds we talked + + align:start position:0% +sort of alternating bonds we talked + + + align:start position:0% +sort of alternating bonds we talked +about it in the context of benzene but + + align:start position:0% +about it in the context of benzene but + + + align:start position:0% +about it in the context of benzene but +see now you know so much more you know + + align:start position:0% +see now you know so much more you know + + + align:start position:0% +see now you know so much more you know +so much more because now you know why + + align:start position:0% +so much more because now you know why + + + align:start position:0% +so much more because now you know why +graphing is so special + + align:start position:0% +graphing is so special + + + align:start position:0% +graphing is so special +you know why graphine is so special it + + align:start position:0% +you know why graphine is so special it + + + align:start position:0% +you know why graphine is so special it +actually is the + + align:start position:0% +actually is the + + + align:start position:0% +actually is the +hybridization it's the hybridization + + align:start position:0% +hybridization it's the hybridization + + + align:start position:0% +hybridization it's the hybridization +because on top and on the bottom of a + + align:start position:0% +because on top and on the bottom of a + + + align:start position:0% +because on top and on the bottom of a +single atom of of a single sheet of + + align:start position:0% +single atom of of a single sheet of + + + align:start position:0% +single atom of of a single sheet of +graphine you've got piie bonding all the + + align:start position:0% +graphine you've got piie bonding all the + + + align:start position:0% +graphine you've got piie bonding all the +way those Pi bonds are going across the + + align:start position:0% +way those Pi bonds are going across the + + + align:start position:0% +way those Pi bonds are going across the +whole surface and those electrons are + + align:start position:0% +whole surface and those electrons are + + + align:start position:0% +whole surface and those electrons are +critical those electrons that occupy + + align:start position:0% +critical those electrons that occupy + + + align:start position:0% +critical those electrons that occupy +those P orbitals are critical to the the + + align:start position:0% +those P orbitals are critical to the the + + + align:start position:0% +those P orbitals are critical to the the +the very special properties that + + align:start position:0% +the very special properties that + + + align:start position:0% +the very special properties that +graphine has right so you now know the + + align:start position:0% +graphine has right so you now know the + + + align:start position:0% +graphine has right so you now know the +secret it's SP2 hybridization and you + + align:start position:0% +secret it's SP2 hybridization and you + + + align:start position:0% +secret it's SP2 hybridization and you +know this has allowed us uh this is you + + align:start position:0% +know this has allowed us uh this is you + + + align:start position:0% +know this has allowed us uh this is you +might tell I'm kind of passionate about + + align:start position:0% +might tell I'm kind of passionate about + + + align:start position:0% +might tell I'm kind of passionate about +this problem um partly I'm passionate + + align:start position:0% +this problem um partly I'm passionate + + + align:start position:0% +this problem um partly I'm passionate +about a lot of problems but also we + + align:start position:0% +about a lot of problems but also we + + + align:start position:0% +about a lot of problems but also we +happen to work on this and we have been + + align:start position:0% +happen to work on this and we have been + + + align:start position:0% +happen to work on this and we have been +developing this this is like the + + align:start position:0% +developing this this is like the + + + align:start position:0% +developing this this is like the +ultimate membrane I can soak this in + + align:start position:0% +ultimate membrane I can soak this in + + + align:start position:0% +ultimate membrane I can soak this in +chlorine overnight I can put it in + + align:start position:0% +chlorine overnight I can put it in + + + align:start position:0% +chlorine overnight I can put it in +Negative PH Solutions I can heat it up + + align:start position:0% +Negative PH Solutions I can heat it up + + + align:start position:0% +Negative PH Solutions I can heat it up +it doesn't + + align:start position:0% +it doesn't + + + align:start position:0% +it doesn't +degrade and we have figured out how to + + align:start position:0% +degrade and we have figured out how to + + + align:start position:0% +degrade and we have figured out how to +poke holes in it at just the right size + + align:start position:0% +poke holes in it at just the right size + + + align:start position:0% +poke holes in it at just the right size +or to stitch it together so that maybe + + align:start position:0% +or to stitch it together so that maybe + + + align:start position:0% +or to stitch it together so that maybe +you can filter particles by the flow in + + align:start position:0% +you can filter particles by the flow in + + + align:start position:0% +you can filter particles by the flow in +between these sheets + + align:start position:0% +between these sheets + + + align:start position:0% +between these sheets +right and this material as a membrane is + + align:start position:0% +right and this material as a membrane is + + + align:start position:0% +right and this material as a membrane is +so promising that uh we've actually + + align:start position:0% +so promising that uh we've actually + + + align:start position:0% +so promising that uh we've actually +started to commercialize it as of the + + align:start position:0% +started to commercialize it as of the + + + align:start position:0% +started to commercialize it as of the +last year right and I think this is + + align:start position:0% +last year right and I think this is + + + align:start position:0% +last year right and I think this is +really going to make a big difference in + + align:start position:0% +really going to make a big difference in + + + align:start position:0% +really going to make a big difference in +a lot of um a lot of areas why because + + align:start position:0% +a lot of um a lot of areas why because + + + align:start position:0% +a lot of um a lot of areas why because +of SP2 hybridization that is why that is + + align:start position:0% +of SP2 hybridization that is why that is + + + align:start position:0% +of SP2 hybridization that is why that is +why this is such a special material okay + + align:start position:0% +why this is such a special material okay + + + align:start position:0% +why this is such a special material okay +that's my why this matters now uh oh we + + align:start position:0% +that's my why this matters now uh oh we + + + align:start position:0% +that's my why this matters now uh oh we +did c2h6 there it is we did C2 H4 there + + align:start position:0% +did c2h6 there it is we did C2 H4 there + + + align:start position:0% +did c2h6 there it is we did C2 H4 there +it is look at that extra P Bond not + + align:start position:0% +it is look at that extra P Bond not + + + align:start position:0% +it is look at that extra P Bond not +anamated this time and of course you can + + align:start position:0% +anamated this time and of course you can + + + align:start position:0% +anamated this time and of course you can +go on and you could do c2h2 and you can + + align:start position:0% +go on and you could do c2h2 and you can + + + align:start position:0% +go on and you could do c2h2 and you can +imagine what happens in this case is is + + align:start position:0% +imagine what happens in this case is is + + + align:start position:0% +imagine what happens in this case is is +what you would expect is what you would + + align:start position:0% +what you would expect is what you would + + + align:start position:0% +what you would expect is what you would +expect because now I've only got see + + align:start position:0% +expect because now I've only got see + + + align:start position:0% +expect because now I've only got see +each of these carbon + + align:start position:0% +each of these carbon + + + align:start position:0% +each of these carbon +atoms only needs two Sigma bonds one to + + align:start position:0% +atoms only needs two Sigma bonds one to + + + align:start position:0% +atoms only needs two Sigma bonds one to +the hydrogen and one to the other carbon + + align:start position:0% +the hydrogen and one to the other carbon + + + align:start position:0% +the hydrogen and one to the other carbon +so it's only going to grab one it's only + + align:start position:0% +so it's only going to grab one it's only + + + align:start position:0% +so it's only going to grab one it's only +only going to hybridize to make those + + align:start position:0% +only going to hybridize to make those + + + align:start position:0% +only going to hybridize to make those +two equivalent Sigma bonds only going to + + align:start position:0% +two equivalent Sigma bonds only going to + + + align:start position:0% +two equivalent Sigma bonds only going to +hybridize with one of the P electrons so + + align:start position:0% +hybridize with one of the P electrons so + + + align:start position:0% +hybridize with one of the P electrons so +that's + + align:start position:0% +that's + + + align:start position:0% +that's +SP that's s hybridization but notice + + align:start position:0% +SP that's s hybridization but notice + + + align:start position:0% +SP that's s hybridization but notice +that in C2 H2 you know now I've got um + + align:start position:0% +that in C2 H2 you know now I've got um + + + align:start position:0% +that in C2 H2 you know now I've got um +two P orbitals left + + align:start position:0% +two P orbitals left + + + align:start position:0% +two P orbitals left +over on each carbon atom and so you can + + align:start position:0% +over on each carbon atom and so you can + + + align:start position:0% +over on each carbon atom and so you can +imagine that with these two P orbitals + + align:start position:0% +imagine that with these two P orbitals + + + align:start position:0% +imagine that with these two P orbitals +well you you know this already right + + align:start position:0% +well you you know this already right + + + align:start position:0% +well you you know this already right +when when we talked about P orbitals we + + align:start position:0% +when when we talked about P orbitals we + + + align:start position:0% +when when we talked about P orbitals we +talked + + align:start position:0% +talked + + + align:start position:0% +talked +about how you know you might you know + + align:start position:0% +about how you know you might you know + + + align:start position:0% +about how you know you might you know +you've got this right + + align:start position:0% +you've got this right + + + align:start position:0% +you've got this right +a okay that's supposed to come like out + + align:start position:0% +a okay that's supposed to come like out + + + align:start position:0% +a okay that's supposed to come like out +of the plane and into the plane they're + + align:start position:0% +of the plane and into the plane they're + + + align:start position:0% +of the plane and into the plane they're +orthogonal they're orthogonal right and + + align:start position:0% +orthogonal they're orthogonal right and + + + align:start position:0% +orthogonal they're orthogonal right and +so so two of them are coming at the + + align:start position:0% +so so two of them are coming at the + + + align:start position:0% +so so two of them are coming at the +other atom one is like this and the + + align:start position:0% +other atom one is like this and the + + + align:start position:0% +other atom one is like this and the +other is like that and the and then the + + align:start position:0% +other is like that and the and then the + + + align:start position:0% +other is like that and the and then the +other Adam has one like this and one + + align:start position:0% +other Adam has one like this and one + + + align:start position:0% +other Adam has one like this and one +well it might not at first but then when + + align:start position:0% +well it might not at first but then when + + + align:start position:0% +well it might not at first but then when +it sees those it's like hey wait a + + align:start position:0% +it sees those it's like hey wait a + + + align:start position:0% +it sees those it's like hey wait a +second if I do this we can pie Bond + + align:start position:0% +second if I do this we can pie Bond + + + align:start position:0% +second if I do this we can pie Bond +but the other ones are like this and + + align:start position:0% +but the other ones are like this and + + + align:start position:0% +but the other ones are like this and +they piie bond and so you get a carbon + + align:start position:0% +they piie bond and so you get a carbon + + + align:start position:0% +they piie bond and so you get a carbon +carbon triple bond right you get a + + align:start position:0% +carbon triple bond right you get a + + + align:start position:0% +carbon triple bond right you get a +carbon carbon triple bond for C uh 2h2 + + align:start position:0% +carbon carbon triple bond for C uh 2h2 + + + align:start position:0% +carbon carbon triple bond for C uh 2h2 +with SP hybridization now it's not oh + + align:start position:0% +with SP hybridization now it's not oh + + + align:start position:0% +with SP hybridization now it's not oh +there it is right okay forms py Bond + + align:start position:0% +there it is right okay forms py Bond + + + align:start position:0% +there it is right okay forms py Bond +Network form Sigma B networ it's not + + align:start position:0% +Network form Sigma B networ it's not + + + align:start position:0% +Network form Sigma B networ it's not +just carbon that hybridizes it's not + + align:start position:0% +just carbon that hybridizes it's not + + + align:start position:0% +just carbon that hybridizes it's not +carbon is a classic example but you know + + align:start position:0% +carbon is a classic example but you know + + + align:start position:0% +carbon is a classic example but you know +if you look at + + align:start position:0% + + + + align:start position:0% + +be2 it's the same thing B H2 well be be + + align:start position:0% +be2 it's the same thing B H2 well be be + + + align:start position:0% +be2 it's the same thing B H2 well be be +starts with an + + align:start position:0% +starts with an + + + align:start position:0% +starts with an +un start can I raise this up be starts + + align:start position:0% +un start can I raise this up be starts + + + align:start position:0% +un start can I raise this up be starts +with orbitals that don't look like + + align:start position:0% +with orbitals that don't look like + + + align:start position:0% +with orbitals that don't look like +they're going to give me the equivalent + + align:start position:0% +they're going to give me the equivalent + + + align:start position:0% +they're going to give me the equivalent +two Sigma bonds be starts with + + align:start position:0% +two Sigma bonds be starts with + + + align:start position:0% +two Sigma bonds be starts with +these s electrons filt + + align:start position:0% +these s electrons filt + + + align:start position:0% +these s electrons filt +right but if be had something more like + + align:start position:0% +right but if be had something more like + + + align:start position:0% +right but if be had something more like +this if it had an SP electron in each of + + align:start position:0% +this if it had an SP electron in each of + + + align:start position:0% +this if it had an SP electron in each of +those orbitals well now when I see the + + align:start position:0% +those orbitals well now when I see the + + + align:start position:0% +those orbitals well now when I see the +two H orbitals the two 1sh + + align:start position:0% +two H orbitals the two 1sh + + + align:start position:0% +two H orbitals the two 1sh +orbitals coming at me I can form those + + align:start position:0% +orbitals coming at me I can form those + + + align:start position:0% +orbitals coming at me I can form those +equivalent bonds so be2 will also + + align:start position:0% +equivalent bonds so be2 will also + + + align:start position:0% +equivalent bonds so be2 will also +hybridize to make that + + align:start position:0% +hybridize to make that + + + align:start position:0% +hybridize to make that +molecule and all sorts of other things + + align:start position:0% +molecule and all sorts of other things + + + align:start position:0% +molecule and all sorts of other things +the D orbitals can get in on the action + + align:start position:0% +the D orbitals can get in on the action + + + align:start position:0% +the D orbitals can get in on the action +right so here's sf6 which we talked + + align:start position:0% +right so here's sf6 which we talked + + + align:start position:0% +right so here's sf6 which we talked +about we drew this Le structure + + align:start position:0% +about we drew this Le structure + + + align:start position:0% +about we drew this Le structure +took a long time to draw those loone + + align:start position:0% +took a long time to draw those loone + + + align:start position:0% +took a long time to draw those loone +pairs but now you know that the way this + + align:start position:0% +pairs but now you know that the way this + + + align:start position:0% +pairs but now you know that the way this +actually works because those are + + align:start position:0% +actually works because those are + + + align:start position:0% +actually works because those are +equivalent bonds so the only way this + + align:start position:0% +equivalent bonds so the only way this + + + align:start position:0% +equivalent bonds so the only way this +can work is if I form hybrid + + align:start position:0% +can work is if I form hybrid + + + align:start position:0% +can work is if I form hybrid +orbitals right right but they didn't + + align:start position:0% +orbitals right right but they didn't + + + align:start position:0% +orbitals right right but they didn't +have to be equivalent bonds until we + + align:start position:0% +have to be equivalent bonds until we + + + align:start position:0% +have to be equivalent bonds until we +learned about Vesper and it said no I + + align:start position:0% +learned about Vesper and it said no I + + + align:start position:0% +learned about Vesper and it said no I +want to maximize my separation to + + align:start position:0% +want to maximize my separation to + + + align:start position:0% +want to maximize my separation to +minimize repulsions and so then we know + + align:start position:0% +minimize repulsions and so then we know + + + align:start position:0% +minimize repulsions and so then we know +that if there are equivalent bonds the + + align:start position:0% +that if there are equivalent bonds the + + + align:start position:0% +that if there are equivalent bonds the +energy of the system will be lower right + + align:start position:0% +energy of the system will be lower right + + + align:start position:0% +energy of the system will be lower right +right and and and so that that's uh you + + align:start position:0% +right and and and so that that's uh you + + + align:start position:0% +right and and and so that that's uh you +know that's that's going to have to take + + align:start position:0% +know that's that's going to have to take + + + align:start position:0% +know that's that's going to have to take +some D orbitals and create these hybrid + + align:start position:0% +some D orbitals and create these hybrid + + + align:start position:0% +some D orbitals and create these hybrid +orbitals look they're beautiful because + + align:start position:0% +orbitals look they're beautiful because + + + align:start position:0% +orbitals look they're beautiful because +now this thing from The sulfur this + + align:start position:0% +now this thing from The sulfur this + + + align:start position:0% +now this thing from The sulfur this +thing can say hey I can take six of you + + align:start position:0% +thing can say hey I can take six of you + + + align:start position:0% +thing can say hey I can take six of you +and I can be equivalent bonding to all + + align:start position:0% +and I can be equivalent bonding to all + + + align:start position:0% +and I can be equivalent bonding to all +of you that's what hybridization is okay + + align:start position:0% +of you that's what hybridization is okay + + + align:start position:0% +of you that's what hybridization is okay +it's it's written right up there we're + + align:start position:0% +it's it's written right up there we're + + + align:start position:0% +it's it's written right up there we're +just keeping on saying the same thing + + align:start position:0% +just keeping on saying the same thing + + + align:start position:0% +just keeping on saying the same thing +okay now + + align:start position:0% +okay now + + + align:start position:0% +okay now +um I think that I'm I got very excited + + align:start position:0% +um I think that I'm I got very excited + + + align:start position:0% +um I think that I'm I got very excited +about the water so I have to throw some + + align:start position:0% +about the water so I have to throw some + + + align:start position:0% +about the water so I have to throw some +T-shirts out um and and now I where do I + + align:start position:0% +T-shirts out um and and now I where do I + + + align:start position:0% +T-shirts out um and and now I where do I +where do I okay I don't go there I don't + + align:start position:0% +where do I okay I don't go there I don't + + + align:start position:0% +where do I okay I don't go there I don't +go there I got to + + align:start position:0% +go there I got to + + + align:start position:0% +go there I got to +go back there and back there and oh + + align:start position:0% +go back there and back there and oh + + + align:start position:0% +go back there and back there and oh +that's very loud okay and right there + + align:start position:0% +that's very loud okay and right there + + + align:start position:0% +that's very loud okay and right there +and right + + align:start position:0% +and right + + + align:start position:0% +and right +there see you guys on + + align:start position:0% + + + + align:start position:0% + +Friday for \ No newline at end of file diff --git a/WXIU2tK4qtc.txt b/WXIU2tK4qtc.txt new file mode 100644 index 0000000000000000000000000000000000000000..7a8b6069bcf5f165ddf44d31a219815ee897901b --- /dev/null +++ b/WXIU2tK4qtc.txt @@ -0,0 +1,1635 @@ +align:start position:0% + +in this segment we developed the + + align:start position:0% +in this segment we developed the + + + align:start position:0% +in this segment we developed the +inclusion exclusion formula which is a + + align:start position:0% +inclusion exclusion formula which is a + + + align:start position:0% +inclusion exclusion formula which is a +beautiful generalization of a formula + + align:start position:0% +beautiful generalization of a formula + + + align:start position:0% +beautiful generalization of a formula +that we have seen before let us look at + + align:start position:0% +that we have seen before let us look at + + + align:start position:0% +that we have seen before let us look at +this formula and remind ourselves what + + align:start position:0% +this formula and remind ourselves what + + + align:start position:0% +this formula and remind ourselves what +it sells if we have two sets a 1 and a 2 + + align:start position:0% +it sells if we have two sets a 1 and a 2 + + + align:start position:0% +it sells if we have two sets a 1 and a 2 +and we're interested in the probability + + align:start position:0% +and we're interested in the probability + + + align:start position:0% +and we're interested in the probability +of their union how can we find it we + + align:start position:0% +of their union how can we find it we + + + align:start position:0% +of their union how can we find it we +take the probability of the first set we + + align:start position:0% +take the probability of the first set we + + + align:start position:0% +take the probability of the first set we +add to 8 the probability of the second + + align:start position:0% +add to 8 the probability of the second + + + align:start position:0% +add to 8 the probability of the second +set but then we realize that by doing so + + align:start position:0% +set but then we realize that by doing so + + + align:start position:0% +set but then we realize that by doing so +we have double counted this part of the + + align:start position:0% +we have double counted this part of the + + + align:start position:0% +we have double counted this part of the +diagram and so we need to correct for + + align:start position:0% +diagram and so we need to correct for + + + align:start position:0% +diagram and so we need to correct for +that and we need to subtract the + + align:start position:0% +that and we need to subtract the + + + align:start position:0% +that and we need to subtract the +probability of this intersection and + + align:start position:0% +probability of this intersection and + + + align:start position:0% +probability of this intersection and +that's how this formula comes about can + + align:start position:0% +that's how this formula comes about can + + + align:start position:0% +that's how this formula comes about can +we generalize this thinking let's say to + + align:start position:0% +we generalize this thinking let's say to + + + align:start position:0% +we generalize this thinking let's say to +the case of three events suppose that we + + align:start position:0% +the case of three events suppose that we + + + align:start position:0% +the case of three events suppose that we +have three events a1 a2 and a3 and we + + align:start position:0% +have three events a1 a2 and a3 and we + + + align:start position:0% +have three events a1 a2 and a3 and we +want to calculate the probability of + + align:start position:0% +want to calculate the probability of + + + align:start position:0% +want to calculate the probability of +their union we first start by adding the + + align:start position:0% +their union we first start by adding the + + + align:start position:0% +their union we first start by adding the +probabilities of the different sets but + + align:start position:0% +probabilities of the different sets but + + + align:start position:0% +probabilities of the different sets but +then we realize that for example this + + align:start position:0% +then we realize that for example this + + + align:start position:0% +then we realize that for example this +part of the diagram has been counted + + align:start position:0% +part of the diagram has been counted + + + align:start position:0% +part of the diagram has been counted +twice it shows up once inside the + + align:start position:0% +twice it shows up once inside the + + + align:start position:0% +twice it shows up once inside the +probability of a1 and once inside the + + align:start position:0% +probability of a1 and once inside the + + + align:start position:0% +probability of a1 and once inside the +probability of a2 so for this reason we + + align:start position:0% +probability of a2 so for this reason we + + + align:start position:0% +probability of a2 so for this reason we +need to make a correction and we need to + + align:start position:0% +need to make a correction and we need to + + + align:start position:0% +need to make a correction and we need to +subtract the probability of this + + align:start position:0% +subtract the probability of this + + + align:start position:0% +subtract the probability of this +intersection similarly subtract the + + align:start position:0% +intersection similarly subtract the + + + align:start position:0% +intersection similarly subtract the +probability of that intersection and of + + align:start position:0% +probability of that intersection and of + + + align:start position:0% +probability of that intersection and of +this one so we subtract the + + align:start position:0% +this one so we subtract the + + + align:start position:0% +this one so we subtract the +probabilities of these intersections but + + align:start position:0% +probabilities of these intersections but + + + align:start position:0% +probabilities of these intersections but +actually the intersections are not just + + align:start position:0% +actually the intersections are not just + + + align:start position:0% +actually the intersections are not just +what I drew here the intersections also + + align:start position:0% +what I drew here the intersections also + + + align:start position:0% +what I drew here the intersections also +involve this part so now let us focus on + + align:start position:0% +involve this part so now let us focus on + + + align:start position:0% +involve this part so now let us focus on +this part of the diagram here a typical + + align:start position:0% +this part of the diagram here a typical + + + align:start position:0% +this part of the diagram here a typical +element that belongs to all three of the + + align:start position:0% +element that belongs to all three of the + + + align:start position:0% +element that belongs to all three of the +sets will show up once here once here + + align:start position:0% +sets will show up once here once here + + + align:start position:0% +sets will show up once here once here +and once there but it will also show up + + align:start position:0% +and once there but it will also show up + + + align:start position:0% +and once there but it will also show up +in all of these intersections and so it + + align:start position:0% +in all of these intersections and so it + + + align:start position:0% +in all of these intersections and so it +shows up three times with the plus sign + + align:start position:0% +shows up three times with the plus sign + + + align:start position:0% +shows up three times with the plus sign +three times with a minus sign which + + align:start position:0% +three times with a minus sign which + + + align:start position:0% +three times with a minus sign which +means that these elements will not + + align:start position:0% +means that these elements will not + + + align:start position:0% +means that these elements will not +counted at all in order to count them we + + align:start position:0% +counted at all in order to count them we + + + align:start position:0% +counted at all in order to count them we +need to add one more term which is the + + align:start position:0% +need to add one more term which is the + + + align:start position:0% +need to add one more term which is the +probability of the three-way + + align:start position:0% +probability of the three-way + + + align:start position:0% +probability of the three-way +intersection so this is the formula for + + align:start position:0% +intersection so this is the formula for + + + align:start position:0% +intersection so this is the formula for +the probability of the union of three + + align:start position:0% +the probability of the union of three + + + align:start position:0% +the probability of the union of three +events it has a rationale similar to + + align:start position:0% +events it has a rationale similar to + + + align:start position:0% +events it has a rationale similar to +this formula and you can convince + + align:start position:0% +this formula and you can convince + + + align:start position:0% +this formula and you can convince +yourself that it is a correct formula by + + align:start position:0% +yourself that it is a correct formula by + + + align:start position:0% +yourself that it is a correct formula by +just looking at the different pieces of + + align:start position:0% +just looking at the different pieces of + + + align:start position:0% +just looking at the different pieces of +this diagram and make sure that each one + + align:start position:0% +this diagram and make sure that each one + + + align:start position:0% +this diagram and make sure that each one +of them is accounted properly but + + align:start position:0% +of them is accounted properly but + + + align:start position:0% +of them is accounted properly but +instead of working in terms of such a + + align:start position:0% +instead of working in terms of such a + + + align:start position:0% +instead of working in terms of such a +picture let us think about a more formal + + align:start position:0% +picture let us think about a more formal + + + align:start position:0% +picture let us think about a more formal +derivation and the formal derivation + + align:start position:0% +derivation and the formal derivation + + + align:start position:0% +derivation and the formal derivation +we'll use a beautiful trick namely + + align:start position:0% +we'll use a beautiful trick namely + + + align:start position:0% +we'll use a beautiful trick namely +indicator functions so here is the + + align:start position:0% +indicator functions so here is the + + + align:start position:0% +indicator functions so here is the +formula that we want to establish and + + align:start position:0% +formula that we want to establish and + + + align:start position:0% +formula that we want to establish and +let us remind ourselves what indicator + + align:start position:0% +let us remind ourselves what indicator + + + align:start position:0% +let us remind ourselves what indicator +functions are 20 set or event we can + + align:start position:0% +functions are 20 set or event we can + + + align:start position:0% +functions are 20 set or event we can +associate an indicator function let's + + align:start position:0% +associate an indicator function let's + + + align:start position:0% +associate an indicator function let's +say that this is the set a I we are + + align:start position:0% +say that this is the set a I we are + + + align:start position:0% +say that this is the set a I we are +going to associate an indicator function + + align:start position:0% +going to associate an indicator function + + + align:start position:0% +going to associate an indicator function +call it X I which is equal to 1 when the + + align:start position:0% +call it X I which is equal to 1 when the + + + align:start position:0% +call it X I which is equal to 1 when the +outcome is inside this set and it's + + align:start position:0% +outcome is inside this set and it's + + + align:start position:0% +outcome is inside this set and it's +going to be zero when the outcome is + + align:start position:0% +going to be zero when the outcome is + + + align:start position:0% +going to be zero when the outcome is +outside what is the indicator function + + align:start position:0% +outside what is the indicator function + + + align:start position:0% +outside what is the indicator function +of the complement the indicator function + + align:start position:0% +of the complement the indicator function + + + align:start position:0% +of the complement the indicator function +of the complement is 1 minus the + + align:start position:0% +of the complement is 1 minus the + + + align:start position:0% +of the complement is 1 minus the +indicator of the event why is this if + + align:start position:0% +indicator of the event why is this if + + + align:start position:0% +indicator of the event why is this if +the outcome is in the complement then X + + align:start position:0% +the outcome is in the complement then X + + + align:start position:0% +the outcome is in the complement then X +I is equal to 0 and this expression is + + align:start position:0% +I is equal to 0 and this expression is + + + align:start position:0% +I is equal to 0 and this expression is +equal to 1 on the other hand if the + + align:start position:0% +equal to 1 on the other hand if the + + + align:start position:0% +equal to 1 on the other hand if the +outcome is inside a I then the indicator + + align:start position:0% +outcome is inside a I then the indicator + + + align:start position:0% +outcome is inside a I then the indicator +function will be equal to 1 and this + + align:start position:0% +function will be equal to 1 and this + + + align:start position:0% +function will be equal to 1 and this +quantity is going to be equal to 0 if we + + align:start position:0% +quantity is going to be equal to 0 if we + + + align:start position:0% +quantity is going to be equal to 0 if we +have the intersection of two events AI + + align:start position:0% +have the intersection of two events AI + + + align:start position:0% +have the intersection of two events AI +and AJ what is their indicator function + + align:start position:0% +and AJ what is their indicator function + + + align:start position:0% +and AJ what is their indicator function +it is X I times XJ this expression is + + align:start position:0% +it is X I times XJ this expression is + + + align:start position:0% +it is X I times XJ this expression is +equal to 1 if and only if X I is equal + + align:start position:0% +equal to 1 if and only if X I is equal + + + align:start position:0% +equal to 1 if and only if X I is equal +to 1 and XJ is equal to 1 which happens + + align:start position:0% +to 1 and XJ is equal to 1 which happens + + + align:start position:0% +to 1 and XJ is equal to 1 which happens +if and only if the outcome is inside AI + + align:start position:0% +if and only if the outcome is inside AI + + + align:start position:0% +if and only if the outcome is inside AI +and also inside AJ + + align:start position:0% +and also inside AJ + + + align:start position:0% +and also inside AJ +now what about the indicator of the + + align:start position:0% +now what about the indicator of the + + + align:start position:0% +now what about the indicator of the +intersection of the complements while + + align:start position:0% +intersection of the complements while + + + align:start position:0% +intersection of the complements while +it's an intersection so the Associated + + align:start position:0% +it's an intersection so the Associated + + + align:start position:0% +it's an intersection so the Associated +indicator function is going to be the + + align:start position:0% +indicator function is going to be the + + + align:start position:0% +indicator function is going to be the +product of the indicator function of the + + align:start position:0% +product of the indicator function of the + + + align:start position:0% +product of the indicator function of the +first set which is 1 minus X I times the + + align:start position:0% +first set which is 1 minus X I times the + + + align:start position:0% +first set which is 1 minus X I times the +indicator function of the second set + + align:start position:0% +indicator function of the second set + + + align:start position:0% +indicator function of the second set +which is 1 minus XJ and finally what is + + align:start position:0% +which is 1 minus XJ and finally what is + + + align:start position:0% +which is 1 minus XJ and finally what is +the indicator function of this event + + align:start position:0% + + + + align:start position:0% + +here we remember the Morgan's laws the + + align:start position:0% +here we remember the Morgan's laws the + + + align:start position:0% +here we remember the Morgan's laws the +Morgan's laws tell us that the + + align:start position:0% +Morgan's laws tell us that the + + + align:start position:0% +Morgan's laws tell us that the +complement of this set the complement of + + align:start position:0% +complement of this set the complement of + + + align:start position:0% +complement of this set the complement of +a union is the intersection of the + + align:start position:0% +a union is the intersection of the + + + align:start position:0% +a union is the intersection of the +complements so this event here is the + + align:start position:0% +complements so this event here is the + + + align:start position:0% +complements so this event here is the +complement of that event and therefore + + align:start position:0% +complement of that event and therefore + + + align:start position:0% +complement of that event and therefore +the Associated indicator function is + + align:start position:0% +the Associated indicator function is + + + align:start position:0% +the Associated indicator function is +going to be 1 minus this expression and + + align:start position:0% +going to be 1 minus this expression and + + + align:start position:0% +going to be 1 minus this expression and +if we were dealing with more than two + + align:start position:0% +if we were dealing with more than two + + + align:start position:0% +if we were dealing with more than two +sets and here we had for example 3-way + + align:start position:0% +sets and here we had for example 3-way + + + align:start position:0% +sets and here we had for example 3-way +intersections you would get the product + + align:start position:0% +intersections you would get the product + + + align:start position:0% +intersections you would get the product +of three terms and if we had a 3-way + + align:start position:0% +of three terms and if we had a 3-way + + + align:start position:0% +of three terms and if we had a 3-way +union we would get a similar expression + + align:start position:0% +union we would get a similar expression + + + align:start position:0% +union we would get a similar expression +except that here we would have again a + + align:start position:0% +except that here we would have again a + + + align:start position:0% +except that here we would have again a +product of three terms instead of two so + + align:start position:0% +product of three terms instead of two so + + + align:start position:0% +product of three terms instead of two so +now let us put to use what we have done + + align:start position:0% +now let us put to use what we have done + + + align:start position:0% +now let us put to use what we have done +so far we are interested in the + + align:start position:0% +so far we are interested in the + + + align:start position:0% +so far we are interested in the +probability that the outcome falls in + + align:start position:0% +probability that the outcome falls in + + + align:start position:0% +probability that the outcome falls in +the union of three sets now an important + + align:start position:0% +the union of three sets now an important + + + align:start position:0% +the union of three sets now an important +fact to remember is that the probability + + align:start position:0% +fact to remember is that the probability + + + align:start position:0% +fact to remember is that the probability +of an event is the same as the expected + + align:start position:0% +of an event is the same as the expected + + + align:start position:0% +of an event is the same as the expected +value of the indicator of that event + + align:start position:0% + + + + align:start position:0% + +this is because the indicator is equal + + align:start position:0% +this is because the indicator is equal + + + align:start position:0% +this is because the indicator is equal +to one if and only if the outcome + + align:start position:0% +to one if and only if the outcome + + + align:start position:0% +to one if and only if the outcome +happens to be inside that set and so the + + align:start position:0% +happens to be inside that set and so the + + + align:start position:0% +happens to be inside that set and so the +contribution that we get to the + + align:start position:0% +contribution that we get to the + + + align:start position:0% +contribution that we get to the +expectation is 1 times the probability + + align:start position:0% +expectation is 1 times the probability + + + align:start position:0% +expectation is 1 times the probability +that the indicator is + + align:start position:0% +that the indicator is + + + align:start position:0% +that the indicator is +which is just this probability now the + + align:start position:0% +which is just this probability now the + + + align:start position:0% +which is just this probability now the +indicator of a three-way union is going + + align:start position:0% +indicator of a three-way union is going + + + align:start position:0% +indicator of a three-way union is going +to be by what we just discussed one - a + + align:start position:0% +to be by what we just discussed one - a + + + align:start position:0% +to be by what we just discussed one - a +product of this kind but now with three + + align:start position:0% +product of this kind but now with three + + + align:start position:0% +product of this kind but now with three +terms let us now calculate this + + align:start position:0% +terms let us now calculate this + + + align:start position:0% +terms let us now calculate this +expectation by expanding the product + + align:start position:0% +expectation by expanding the product + + + align:start position:0% +expectation by expanding the product +involved we have this first term then + + align:start position:0% +involved we have this first term then + + + align:start position:0% +involved we have this first term then +when we multiply those three terms + + align:start position:0% +when we multiply those three terms + + + align:start position:0% +when we multiply those three terms +together we're going to get a bunch of + + align:start position:0% +together we're going to get a bunch of + + + align:start position:0% +together we're going to get a bunch of +contributions one contribution with a + + align:start position:0% +contributions one contribution with a + + + align:start position:0% +contributions one contribution with a +minus sign is 1 times 1 times 1 another + + align:start position:0% +minus sign is 1 times 1 times 1 another + + + align:start position:0% +minus sign is 1 times 1 times 1 another +contribution would be minus - that's a + + align:start position:0% +contribution would be minus - that's a + + + align:start position:0% +contribution would be minus - that's a +plus X 1 times 1 times 1 and similarly + + align:start position:0% +plus X 1 times 1 times 1 and similarly + + + align:start position:0% +plus X 1 times 1 times 1 and similarly +we get a contribution of X 2 and X 3 and + + align:start position:0% +we get a contribution of X 2 and X 3 and + + + align:start position:0% +we get a contribution of X 2 and X 3 and +then we have a contribution such as X 1 + + align:start position:0% +then we have a contribution such as X 1 + + + align:start position:0% +then we have a contribution such as X 1 +times X 2 times 1 and if you look at the + + align:start position:0% +times X 2 times 1 and if you look at the + + + align:start position:0% +times X 2 times 1 and if you look at the +minus signs there are 3 minus is + + align:start position:0% +minus signs there are 3 minus is + + + align:start position:0% +minus signs there are 3 minus is +involved so overall it's going to be a + + align:start position:0% +involved so overall it's going to be a + + + align:start position:0% +involved so overall it's going to be a +minus minus x1 times x2 and then there + + align:start position:0% +minus minus x1 times x2 and then there + + + align:start position:0% +minus minus x1 times x2 and then there +is going to be similar terms such as x1 + + align:start position:0% +is going to be similar terms such as x1 + + + align:start position:0% +is going to be similar terms such as x1 +x3 and x2 x3 and finally there's going + + align:start position:0% +x3 and x2 x3 and finally there's going + + + align:start position:0% +x3 and x2 x3 and finally there's going +to be a term x1 times x2 times x3 + + align:start position:0% +to be a term x1 times x2 times x3 + + + align:start position:0% +to be a term x1 times x2 times x3 +there's a total of 4 minus signs + + align:start position:0% +there's a total of 4 minus signs + + + align:start position:0% +there's a total of 4 minus signs +involved so everything shows up in the + + align:start position:0% +involved so everything shows up in the + + + align:start position:0% +involved so everything shows up in the +end with a plus sign so the probability + + align:start position:0% +end with a plus sign so the probability + + + align:start position:0% +end with a plus sign so the probability +of this event is equal to the + + align:start position:0% +of this event is equal to the + + + align:start position:0% +of this event is equal to the +expectation of this random variable here + + align:start position:0% +expectation of this random variable here + + + align:start position:0% +expectation of this random variable here +we notice that the ones cancel out the + + align:start position:0% +we notice that the ones cancel out the + + + align:start position:0% +we notice that the ones cancel out the +expected value of x1 for an indicator + + align:start position:0% +expected value of x1 for an indicator + + + align:start position:0% +expected value of x1 for an indicator +variable is just the probability of that + + align:start position:0% +variable is just the probability of that + + + align:start position:0% +variable is just the probability of that +event and we get this term the expected + + align:start position:0% +event and we get this term the expected + + + align:start position:0% +event and we get this term the expected +value of x2 and x3 give us these terms + + align:start position:0% +value of x2 and x3 give us these terms + + + align:start position:0% +value of x2 and x3 give us these terms +the expected value of x1 times x2 this + + align:start position:0% +the expected value of x1 times x2 this + + + align:start position:0% +the expected value of x1 times x2 this +is the indicator random variable of the + + align:start position:0% +is the indicator random variable of the + + + align:start position:0% +is the indicator random variable of the +intersection so the expected value of + + align:start position:0% +intersection so the expected value of + + + align:start position:0% +intersection so the expected value of +this term is just the probability of the + + align:start position:0% +this term is just the probability of the + + + align:start position:0% +this term is just the probability of the +intersection of a1 and a2 + + align:start position:0% +intersection of a1 and a2 + + + align:start position:0% +intersection of a1 and a2 +and similarly these terms here give rise + + align:start position:0% +and similarly these terms here give rise + + + align:start position:0% +and similarly these terms here give rise +to those two terms here finally x1 times + + align:start position:0% +to those two terms here finally x1 times + + + align:start position:0% +to those two terms here finally x1 times +x2 times x3 is the indicator variable + + align:start position:0% +x2 times x3 is the indicator variable + + + align:start position:0% +x2 times x3 is the indicator variable +for the event a 1 intersection a 2 + + align:start position:0% +for the event a 1 intersection a 2 + + + align:start position:0% +for the event a 1 intersection a 2 +intersection a 3 therefore the expected + + align:start position:0% +intersection a 3 therefore the expected + + + align:start position:0% +intersection a 3 therefore the expected +value of this term is equal to this + + align:start position:0% +value of this term is equal to this + + + align:start position:0% +value of this term is equal to this +probability and therefore we have + + align:start position:0% +probability and therefore we have + + + align:start position:0% +probability and therefore we have +established exactly the formula that we + + align:start position:0% +established exactly the formula that we + + + align:start position:0% +established exactly the formula that we +wanted to establish now this derivation + + align:start position:0% +wanted to establish now this derivation + + + align:start position:0% +wanted to establish now this derivation +that we carried out here there's nothing + + align:start position:0% +that we carried out here there's nothing + + + align:start position:0% +that we carried out here there's nothing +special about the case of three we could + + align:start position:0% +special about the case of three we could + + + align:start position:0% +special about the case of three we could +have the union of many more events we + + align:start position:0% +have the union of many more events we + + + align:start position:0% +have the union of many more events we +would just have here the product of more + + align:start position:0% +would just have here the product of more + + + align:start position:0% +would just have here the product of more +terms and we would need to carry out the + + align:start position:0% +terms and we would need to carry out the + + + align:start position:0% +terms and we would need to carry out the +multiplication and we would get cross + + align:start position:0% +multiplication and we would get cross + + + align:start position:0% +multiplication and we would get cross +terms of all types involving just one of + + align:start position:0% +terms of all types involving just one of + + + align:start position:0% +terms of all types involving just one of +the indicator variables or products of + + align:start position:0% +the indicator variables or products of + + + align:start position:0% +the indicator variables or products of +two indicator variables or products of + + align:start position:0% +two indicator variables or products of + + + align:start position:0% +two indicator variables or products of +three indicator variables and so on and + + align:start position:0% +three indicator variables and so on and + + + align:start position:0% +three indicator variables and so on and +after you carry out this exercise and + + align:start position:0% +after you carry out this exercise and + + + align:start position:0% +after you carry out this exercise and +keep track of the various terms you end + + align:start position:0% +keep track of the various terms you end + + + align:start position:0% +keep track of the various terms you end +up with this general version of what is + + align:start position:0% +up with this general version of what is + + + align:start position:0% +up with this general version of what is +called the inclusion exclusion formula + + align:start position:0% +called the inclusion exclusion formula + + + align:start position:0% +called the inclusion exclusion formula +so the probability of a union is there's + + align:start position:0% +so the probability of a union is there's + + + align:start position:0% +so the probability of a union is there's +the sum of the probabilities but then + + align:start position:0% +the sum of the probabilities but then + + + align:start position:0% +the sum of the probabilities but then +you subtract all possible probabilities + + align:start position:0% +you subtract all possible probabilities + + + align:start position:0% +you subtract all possible probabilities +of two-way intersections then we add + + align:start position:0% +of two-way intersections then we add + + + align:start position:0% +of two-way intersections then we add +probabilities of 3-way intersections + + align:start position:0% +probabilities of 3-way intersections + + + align:start position:0% +probabilities of 3-way intersections +then you subtract probabilities of + + align:start position:0% +then you subtract probabilities of + + + align:start position:0% +then you subtract probabilities of +four-way intersections and you keep + + align:start position:0% +four-way intersections and you keep + + + align:start position:0% +four-way intersections and you keep +going this way alternating signs until + + align:start position:0% +going this way alternating signs until + + + align:start position:0% +going this way alternating signs until +you get to the last term which is the + + align:start position:0% +you get to the last term which is the + + + align:start position:0% +you get to the last term which is the +probability of the intersection of all + + align:start position:0% +probability of the intersection of all + + + align:start position:0% +probability of the intersection of all +the events involved and this exponent + + align:start position:0% +the events involved and this exponent + + + align:start position:0% +the events involved and this exponent +here of n minus 1 is the exponent that + + align:start position:0% +here of n minus 1 is the exponent that + + + align:start position:0% +here of n minus 1 is the exponent that +you need so that the last term has the + + align:start position:0% +you need so that the last term has the + + + align:start position:0% +you need so that the last term has the +correct sign so for example if n is + + align:start position:0% +correct sign so for example if n is + + + align:start position:0% +correct sign so for example if n is +equal to 3 the exponent would be 2 so + + align:start position:0% +equal to 3 the exponent would be 2 so + + + align:start position:0% +equal to 3 the exponent would be 2 so +this could be a plus sign which is + + align:start position:0% +this could be a plus sign which is + + + align:start position:0% +this could be a plus sign which is +consistent with what we got here so this + + align:start position:0% +consistent with what we got here so this + + + align:start position:0% +consistent with what we got here so this +is a formula that is quite useful when + + align:start position:0% +is a formula that is quite useful when + + + align:start position:0% +is a formula that is quite useful when +you want to calculate probabilities of + + align:start position:0% +you want to calculate probabilities of + + + align:start position:0% +you want to calculate probabilities of +unions of events but also this + + align:start position:0% +unions of events but also this + + + align:start position:0% +unions of events but also this +derivation using + + align:start position:0% +derivation using + + + align:start position:0% +derivation using +indicator functions is quite beautiful \ No newline at end of file diff --git a/XX7ePR21Ook.txt b/XX7ePR21Ook.txt new file mode 100644 index 0000000000000000000000000000000000000000..22d801cb6813589a3fdec684d78ec14a75c38647 --- /dev/null +++ b/XX7ePR21Ook.txt @@ -0,0 +1,11770 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit M opencourseware at + + align:start position:0% + + + + align:start position:0% + +ocw.mit.edu so let's get + + align:start position:0% +ocw.mit.edu so let's get + + + align:start position:0% +ocw.mit.edu so let's get +ready um if good you should receive some + + align:start position:0% +ready um if good you should receive some + + + align:start position:0% +ready um if good you should receive some +handouts so the TA are walking + + align:start position:0% + + + + align:start position:0% + +around so you should slowly get those um + + align:start position:0% +around so you should slowly get those um + + + align:start position:0% +around so you should slowly get those um +this is the second lecture on number + + align:start position:0% +this is the second lecture on number + + + align:start position:0% +this is the second lecture on number +Theory and we're going to cover a lot of + + align:start position:0% +Theory and we're going to cover a lot of + + + align:start position:0% +Theory and we're going to cover a lot of +stuff and actually we're going to start + + align:start position:0% +stuff and actually we're going to start + + + align:start position:0% +stuff and actually we're going to start +with uh um encryption which is an + + align:start position:0% +with uh um encryption which is an + + + align:start position:0% +with uh um encryption which is an +application of number Theory and we will + + align:start position:0% +application of number Theory and we will + + + align:start position:0% +application of number Theory and we will +take that as a theme throughout the + + align:start position:0% +take that as a theme throughout the + + + align:start position:0% +take that as a theme throughout the +whole lecture and so in this way you can + + align:start position:0% +whole lecture and so in this way you can + + + align:start position:0% +whole lecture and so in this way you can +see how useful number theory is + + align:start position:0% +see how useful number theory is + + + align:start position:0% +see how useful number theory is +um now um encryption + + align:start position:0% +um now um encryption + + + align:start position:0% +um now um encryption +uh yeah what is it so let's first talk + + align:start position:0% +uh yeah what is it so let's first talk + + + align:start position:0% +uh yeah what is it so let's first talk +about that a little bit maybe some of + + align:start position:0% +about that a little bit maybe some of + + + align:start position:0% +about that a little bit maybe some of +you have heard about it but cryptology + + align:start position:0% +you have heard about it but cryptology + + + align:start position:0% +you have heard about it but cryptology +in general is the art of hiding uh + + align:start position:0% +in general is the art of hiding uh + + + align:start position:0% +in general is the art of hiding uh +information and encryption is a very + + align:start position:0% +information and encryption is a very + + + align:start position:0% +information and encryption is a very +useful tool I will only give a very high + + align:start position:0% +useful tool I will only give a very high + + + align:start position:0% +useful tool I will only give a very high +level overview I mean if you really want + + align:start position:0% +level overview I mean if you really want + + + align:start position:0% +level overview I mean if you really want +to know more about this you should do a + + align:start position:0% +to know more about this you should do a + + + align:start position:0% +to know more about this you should do a +class in in in crypto or or or or + + align:start position:0% +class in in in crypto or or or or + + + align:start position:0% +class in in in crypto or or or or +practical + + align:start position:0% +practical + + + align:start position:0% +practical +security um so what's + + align:start position:0% + + + + align:start position:0% + +encryption um the idea is usually that + + align:start position:0% +encryption um the idea is usually that + + + align:start position:0% +encryption um the idea is usually that +beforehand um we're going to + + align:start position:0% +beforehand um we're going to + + + align:start position:0% +beforehand um we're going to +share a whole bunch of + + align:start position:0% +share a whole bunch of + + + align:start position:0% +share a whole bunch of +keys so keys + + align:start position:0% +keys so keys + + + align:start position:0% +keys so keys +are + + align:start position:0% + + + + align:start position:0% + +exchanged uh between a receiver and a + + align:start position:0% +exchanged uh between a receiver and a + + + align:start position:0% +exchanged uh between a receiver and a +sender and the whole idea is that if I + + align:start position:0% +sender and the whole idea is that if I + + + align:start position:0% +sender and the whole idea is that if I +want to transmit like a message to one + + align:start position:0% +want to transmit like a message to one + + + align:start position:0% +want to transmit like a message to one +of you uh well there could be someone in + + align:start position:0% +of you uh well there could be someone in + + + align:start position:0% +of you uh well there could be someone in +the middle who wants to intercept my my + + align:start position:0% +the middle who wants to intercept my my + + + align:start position:0% +the middle who wants to intercept my my +message and wants to find find out what + + align:start position:0% +message and wants to find find out what + + + align:start position:0% +message and wants to find find out what +I'm saying so I do not like this and in + + align:start position:0% +I'm saying so I do not like this and in + + + align:start position:0% +I'm saying so I do not like this and in +order to avoid it I will use encryption + + align:start position:0% +order to avoid it I will use encryption + + + align:start position:0% +order to avoid it I will use encryption +which is some kind of algorithm that + + align:start position:0% +which is some kind of algorithm that + + + align:start position:0% +which is some kind of algorithm that +actually uh + + align:start position:0% +actually uh + + + align:start position:0% +actually uh +transforms um my message M my plain + + align:start position:0% +transforms um my message M my plain + + + align:start position:0% +transforms um my message M my plain +message by using some kind of algorithm + + align:start position:0% +message by using some kind of algorithm + + + align:start position:0% +message by using some kind of algorithm +e some encryption algorithm uh it can be + + align:start position:0% +e some encryption algorithm uh it can be + + + align:start position:0% +e some encryption algorithm uh it can be +a function as well um that uses the keys + + align:start position:0% +a function as well um that uses the keys + + + align:start position:0% +a function as well um that uses the keys +in order to + + align:start position:0% +in order to + + + align:start position:0% +in order to +transform this into an encryption which + + align:start position:0% +transform this into an encryption which + + + align:start position:0% +transform this into an encryption which +we call M Prime here so the plain text + + align:start position:0% +we call M Prime here so the plain text + + + align:start position:0% +we call M Prime here so the plain text +uh has in the clear all the information + + align:start position:0% +uh has in the clear all the information + + + align:start position:0% +uh has in the clear all the information +that I want to convey to one of you for + + align:start position:0% +that I want to convey to one of you for + + + align:start position:0% +that I want to convey to one of you for +example and M Prime is somehow uh a + + align:start position:0% +example and M Prime is somehow uh a + + + align:start position:0% +example and M Prime is somehow uh a +complete + + align:start position:0% +complete + + + align:start position:0% +complete +uh uh well uh mixture of bits uh out of + + align:start position:0% +uh uh well uh mixture of bits uh out of + + + align:start position:0% +uh uh well uh mixture of bits uh out of +which I'm not able to distill any + + align:start position:0% +which I'm not able to distill any + + + align:start position:0% +which I'm not able to distill any +information about the plain text so + + align:start position:0% +information about the plain text so + + + align:start position:0% +information about the plain text so +encryption is a very special kind of + + align:start position:0% +encryption is a very special kind of + + + align:start position:0% +encryption is a very special kind of +thing and we're not going to talk about + + align:start position:0% +thing and we're not going to talk about + + + align:start position:0% +thing and we're not going to talk about +the precise definitions here but we just + + align:start position:0% +the precise definitions here but we just + + + align:start position:0% +the precise definitions here but we just +take the ID into uh this lecture now + + align:start position:0% +take the ID into uh this lecture now + + + align:start position:0% +take the ID into uh this lecture now +decryption is uh transforming the cipher + + align:start position:0% +decryption is uh transforming the cipher + + + align:start position:0% +decryption is uh transforming the cipher +text back into the plain text so we will + + align:start position:0% +text back into the plain text so we will + + + align:start position:0% +text back into the plain text so we will +start with the encryption uh M Prime and + + align:start position:0% +start with the encryption uh M Prime and + + + align:start position:0% +start with the encryption uh M Prime and +we have some kind of decryption + + align:start position:0% +we have some kind of decryption + + + align:start position:0% +we have some kind of decryption +algorithm and again we can make use of + + align:start position:0% +algorithm and again we can make use of + + + align:start position:0% +algorithm and again we can make use of +the keys that we + + align:start position:0% +the keys that we + + + align:start position:0% +the keys that we +exchanged and we transform it back into + + align:start position:0% +exchanged and we transform it back into + + + align:start position:0% +exchanged and we transform it back into +the plain message so only if I know the + + align:start position:0% +the plain message so only if I know the + + + align:start position:0% +the plain message so only if I know the +keys I can actually transform back the + + align:start position:0% +keys I can actually transform back the + + + align:start position:0% +keys I can actually transform back the +encrypted version into the plain + + align:start position:0% +encrypted version into the plain + + + align:start position:0% +encrypted version into the plain +version so well in encryption schemes we + + align:start position:0% +version so well in encryption schemes we + + + align:start position:0% +version so well in encryption schemes we +like both these algorithms to be really + + align:start position:0% +like both these algorithms to be really + + + align:start position:0% +like both these algorithms to be really +really efficient and um the security of + + align:start position:0% +really efficient and um the security of + + + align:start position:0% +really efficient and um the security of +such a scheme well the first kind of + + align:start position:0% +such a scheme well the first kind of + + + align:start position:0% +such a scheme well the first kind of +intuition that we can get is that well + + align:start position:0% +intuition that we can get is that well + + + align:start position:0% +intuition that we can get is that well +if I'm a man in the middle somewhere + + align:start position:0% +if I'm a man in the middle somewhere + + + align:start position:0% +if I'm a man in the middle somewhere +intercepting like an encrypted message M + + align:start position:0% +intercepting like an encrypted message M + + + align:start position:0% +intercepting like an encrypted message M +Prime I should not be able to get any + + align:start position:0% +Prime I should not be able to get any + + + align:start position:0% +Prime I should not be able to get any +information about M if I have no + + align:start position:0% +information about M if I have no + + + align:start position:0% +information about M if I have no +knowledge about those + + align:start position:0% +knowledge about those + + + align:start position:0% +knowledge about those +keys so this is uh uh the example that + + align:start position:0% +keys so this is uh uh the example that + + + align:start position:0% +keys so this is uh uh the example that +we're going to take throughout this + + align:start position:0% +we're going to take throughout this + + + align:start position:0% +we're going to take throughout this +whole uh + + align:start position:0% +whole uh + + + align:start position:0% +whole uh +lecture so let's start with uh a first + + align:start position:0% +lecture so let's start with uh a first + + + align:start position:0% +lecture so let's start with uh a first +um uh possible scheme um churing who + + align:start position:0% +um uh possible scheme um churing who + + + align:start position:0% +um uh possible scheme um churing who +lived like uh around 1900 um I think 36 + + align:start position:0% +lived like uh around 1900 um I think 36 + + + align:start position:0% +lived like uh around 1900 um I think 36 +he was 24 years old and he lived uh till + + align:start position:0% +he was 24 years old and he lived uh till + + + align:start position:0% +he was 24 years old and he lived uh till +about actually I think he was about 54 + + align:start position:0% +about actually I think he was about 54 + + + align:start position:0% +about actually I think he was about 54 +when he died um in any case churing was + + align:start position:0% +when he died um in any case churing was + + + align:start position:0% +when he died um in any case churing was +the one who first originally proposed um + + align:start position:0% +the one who first originally proposed um + + + align:start position:0% +the one who first originally proposed um +to use number theory in cryptography and + + align:start position:0% +to use number theory in cryptography and + + + align:start position:0% +to use number theory in cryptography and +uh before he joined the British army + + align:start position:0% +uh before he joined the British army + + + align:start position:0% +uh before he joined the British army +before the second world war he actually + + align:start position:0% +before the second world war he actually + + + align:start position:0% +before the second world war he actually +um uh proposed a scheme but it got never + + align:start position:0% +um uh proposed a scheme but it got never + + + align:start position:0% +um uh proposed a scheme but it got never +published so here in this class we are + + align:start position:0% +published so here in this class we are + + + align:start position:0% +published so here in this class we are +going to uh try to think about what he + + align:start position:0% +going to uh try to think about what he + + + align:start position:0% +going to uh try to think about what he +could have thought about so we will have + + align:start position:0% +could have thought about so we will have + + + align:start position:0% +could have thought about so we will have +a first scheme uh which we we will call + + align:start position:0% +a first scheme uh which we we will call + + + align:start position:0% +a first scheme uh which we we will call +churing + + align:start position:0% +churing + + + align:start position:0% +churing +code version number + + align:start position:0% +code version number + + + align:start position:0% +code version number +one and uh the whole idea is that we + + align:start position:0% +one and uh the whole idea is that we + + + align:start position:0% +one and uh the whole idea is that we +going to translate a message first of + + align:start position:0% +going to translate a message first of + + + align:start position:0% +going to translate a message first of +all into a prime number uh because we + + align:start position:0% +all into a prime number uh because we + + + align:start position:0% +all into a prime number uh because we +want to use numbers you're here in + + align:start position:0% +want to use numbers you're here in + + + align:start position:0% +want to use numbers you're here in +number Theory class so we want to use + + align:start position:0% +number Theory class so we want to use + + + align:start position:0% +number Theory class so we want to use +some tricks with numbers in order to + + align:start position:0% +some tricks with numbers in order to + + + align:start position:0% +some tricks with numbers in order to +encrypt it so let's do + + align:start position:0% +encrypt it so let's do + + + align:start position:0% +encrypt it so let's do +this + + align:start position:0% +this + + + align:start position:0% +this +um so for example let's take the word uh + + align:start position:0% +um so for example let's take the word uh + + + align:start position:0% +um so for example let's take the word uh +victory + + align:start position:0% +victory + + + align:start position:0% +victory +uh we can map this into an integer for + + align:start position:0% +uh we can map this into an integer for + + + align:start position:0% +uh we can map this into an integer for +example we could say well m is um 22 + + align:start position:0% +example we could say well m is um 22 + + + align:start position:0% +example we could say well m is um 22 +where I map V to because I know that V + + align:start position:0% +where I map V to because I know that V + + + align:start position:0% +where I map V to because I know that V +is the 22nd letter in the alphabet I + + align:start position:0% +is the 22nd letter in the alphabet I + + + align:start position:0% +is the 22nd letter in the alphabet I +just start with 22 I is the ninth letter + + align:start position:0% +just start with 22 I is the ninth letter + + + align:start position:0% +just start with 22 I is the ninth letter +in the AL in in the alphabet so ient + + align:start position:0% +in the AL in in the alphabet so ient + + + align:start position:0% +in the AL in in the alphabet so ient +09 uh C is the third letter in the + + align:start position:0% +09 uh C is the third letter in the + + + align:start position:0% +09 uh C is the third letter in the +alphabet I append a three 03 I continue + + align:start position:0% +alphabet I append a three 03 I continue + + + align:start position:0% +alphabet I append a three 03 I continue +like this + + align:start position:0% +like this + + + align:start position:0% +like this +and in the end over here I have mapped y + + align:start position:0% +and in the end over here I have mapped y + + + align:start position:0% +and in the end over here I have mapped y +to the 25th letter because it's the 25th + + align:start position:0% +to the 25th letter because it's the 25th + + + align:start position:0% +to the 25th letter because it's the 25th +letter of the alphabet I write 25 it + + align:start position:0% +letter of the alphabet I write 25 it + + + align:start position:0% +letter of the alphabet I write 25 it +turns out I can just add a couple of + + align:start position:0% +turns out I can just add a couple of + + + align:start position:0% +turns out I can just add a couple of +digits more if I specially compute those + + align:start position:0% +digits more if I specially compute those + + + align:start position:0% +digits more if I specially compute those +in this case I could add 13 and then it + + align:start position:0% +in this case I could add 13 and then it + + + align:start position:0% +in this case I could add 13 and then it +changes into a prime + + align:start position:0% +changes into a prime + + + align:start position:0% +changes into a prime +number um now we're not going to talk + + align:start position:0% +number um now we're not going to talk + + + align:start position:0% +number um now we're not going to talk +about why this is and how this can be + + align:start position:0% +about why this is and how this can be + + + align:start position:0% +about why this is and how this can be +done and so on but uh it turns out that + + align:start position:0% +done and so on but uh it turns out that + + + align:start position:0% +done and so on but uh it turns out that +the prime numbers are densely uh + + align:start position:0% +the prime numbers are densely uh + + + align:start position:0% +the prime numbers are densely uh +distributed over the integers and it is + + align:start position:0% +distributed over the integers and it is + + + align:start position:0% +distributed over the integers and it is +really possible to just with a few extra + + align:start position:0% +really possible to just with a few extra + + + align:start position:0% +really possible to just with a few extra +digits uh by selecting them in a smart + + align:start position:0% +digits uh by selecting them in a smart + + + align:start position:0% +digits uh by selecting them in a smart +way to actually create a prime number + + align:start position:0% +way to actually create a prime number + + + align:start position:0% +way to actually create a prime number +and also verify that it is a prime + + align:start position:0% +and also verify that it is a prime + + + align:start position:0% +and also verify that it is a prime +number very efficiently so it's very + + align:start position:0% +number very efficiently so it's very + + + align:start position:0% +number very efficiently so it's very +easy to compute uh to translate such a + + align:start position:0% +easy to compute uh to translate such a + + + align:start position:0% +easy to compute uh to translate such a +word into a prime number so this is how + + align:start position:0% +word into a prime number so this is how + + + align:start position:0% +word into a prime number so this is how +it all starts and just like in an + + align:start position:0% +it all starts and just like in an + + + align:start position:0% +it all starts and just like in an +encryption scheme um beforehand we are + + align:start position:0% +encryption scheme um beforehand we are + + + align:start position:0% +encryption scheme um beforehand we are +going to + + align:start position:0% +going to + + + align:start position:0% +going to +um + + align:start position:0% +um + + + align:start position:0% +um +exchange a key so we + + align:start position:0% + + + + align:start position:0% + +exchange a secret uh Prime in this + + align:start position:0% +exchange a secret uh Prime in this + + + align:start position:0% +exchange a secret uh Prime in this +example which we call + + align:start position:0% +example which we call + + + align:start position:0% +example which we call +K and the + + align:start position:0% +K and the + + + align:start position:0% +K and the +encryption is very simple we are just + + align:start position:0% +encryption is very simple we are just + + + align:start position:0% +encryption is very simple we are just +going to + + align:start position:0% +going to + + + align:start position:0% +going to +multiply M with K you may wonder why is + + align:start position:0% +multiply M with K you may wonder why is + + + align:start position:0% +multiply M with K you may wonder why is +this such a fantastic ID but let's uh + + align:start position:0% +this such a fantastic ID but let's uh + + + align:start position:0% +this such a fantastic ID but let's uh +let's bear with me so m is this first + + align:start position:0% +let's bear with me so m is this first + + + align:start position:0% +let's bear with me so m is this first +prime number and we multiply it by + + align:start position:0% +prime number and we multiply it by + + + align:start position:0% +prime number and we multiply it by +second prime number and that's going to + + align:start position:0% +second prime number and that's going to + + + align:start position:0% +second prime number and that's going to +be our + + align:start position:0% +be our + + + align:start position:0% +be our +encryption now how do we decrypt that + + align:start position:0% +encryption now how do we decrypt that + + + align:start position:0% +encryption now how do we decrypt that +seems to be pretty straightforward right + + align:start position:0% +seems to be pretty straightforward right + + + align:start position:0% +seems to be pretty straightforward right +how do we do it uh we start off with M + + align:start position:0% +how do we do it uh we start off with M + + + align:start position:0% +how do we do it uh we start off with M +Prime um I know we have exchanged the + + align:start position:0% +Prime um I know we have exchanged the + + + align:start position:0% +Prime um I know we have exchanged the +secret Prime K so if I receive uh from + + align:start position:0% +secret Prime K so if I receive uh from + + + align:start position:0% +secret Prime K so if I receive uh from +you this message this encrypted message + + align:start position:0% +you this message this encrypted message + + + align:start position:0% +you this message this encrypted message +well I know the key K so I just divide + + align:start position:0% +well I know the key K so I just divide + + + align:start position:0% +well I know the key K so I just divide +it by K + + align:start position:0% +it by K + + + align:start position:0% +it by K +well which is MK / K and I get M so + + align:start position:0% +well which is MK / K and I get M so + + + align:start position:0% +well which is MK / K and I get M so +that's pretty + + align:start position:0% +that's pretty + + + align:start position:0% +that's pretty +straightforward now turn it turns out + + align:start position:0% +straightforward now turn it turns out + + + align:start position:0% +straightforward now turn it turns out +actually and I'll will write it up here + + align:start position:0% +actually and I'll will write it up here + + + align:start position:0% +actually and I'll will write it up here +because you need it later that uh it's + + align:start position:0% +because you need it later that uh it's + + + align:start position:0% +because you need it later that uh it's +not so trivial to actually just given an + + align:start position:0% +not so trivial to actually just given an + + + align:start position:0% +not so trivial to actually just given an +M Prime to figure out what m is or + + align:start position:0% +M Prime to figure out what m is or + + + align:start position:0% +M Prime to figure out what m is or +k m Prime is the product of two very + + align:start position:0% +k m Prime is the product of two very + + + align:start position:0% +k m Prime is the product of two very +large prime numbers and uh that turns + + align:start position:0% +large prime numbers and uh that turns + + + align:start position:0% +large prime numbers and uh that turns +out to be a really hard problem up to + + align:start position:0% +out to be a really hard problem up to + + + align:start position:0% +out to be a really hard problem up to +now nobody has really been able to get a + + align:start position:0% +now nobody has really been able to get a + + + align:start position:0% +now nobody has really been able to get a +really efficient algorithm to solve that + + align:start position:0% +really efficient algorithm to solve that + + + align:start position:0% +really efficient algorithm to solve that +so we may think this is secure so let me + + align:start position:0% +so we may think this is secure so let me + + + align:start position:0% +so we may think this is secure so let me +write it down um it's + + align:start position:0% + + + + align:start position:0% + +hard to + + align:start position:0% +hard to + + + align:start position:0% +hard to +factor a uh product of two large + + align:start position:0% + + + + align:start position:0% + +primes you will actually need this also + + align:start position:0% +primes you will actually need this also + + + align:start position:0% +primes you will actually need this also +Al when we come to the final encryption + + align:start position:0% +Al when we come to the final encryption + + + align:start position:0% +Al when we come to the final encryption +scheme RSA that we will discuss which is + + align:start position:0% +scheme RSA that we will discuss which is + + + align:start position:0% +scheme RSA that we will discuss which is +widely used um + + align:start position:0% + + + + align:start position:0% + +so but something is wrong here though + + align:start position:0% +so but something is wrong here though + + + align:start position:0% +so but something is wrong here though +this seems to be too simple right so + + align:start position:0% +this seems to be too simple right so + + + align:start position:0% +this seems to be too simple right so +what can we do if we have like say + + align:start position:0% +what can we do if we have like say + + + align:start position:0% +what can we do if we have like say +suppose I intercept two encrypted + + align:start position:0% +suppose I intercept two encrypted + + + align:start position:0% +suppose I intercept two encrypted +messages what what can I do + + align:start position:0% + + + + align:start position:0% + +so suppose I have uh a first message uh + + align:start position:0% +so suppose I have uh a first message uh + + + align:start position:0% +so suppose I have uh a first message uh +M Prime 1 which is the product of a + + align:start position:0% +M Prime 1 which is the product of a + + + align:start position:0% +M Prime 1 which is the product of a +first plane message times the key K and + + align:start position:0% +first plane message times the key K and + + + align:start position:0% +first plane message times the key K and +I have a second message that is + + align:start position:0% +I have a second message that is + + + align:start position:0% +I have a second message that is +encrypted by using the same key which is + + align:start position:0% +encrypted by using the same key which is + + + align:start position:0% +encrypted by using the same key which is +M2 * K does anybody has an idea what I + + align:start position:0% +M2 * K does anybody has an idea what I + + + align:start position:0% +M2 * K does anybody has an idea what I +could do here yeah + + align:start position:0% +could do here yeah + + + align:start position:0% +could do here yeah +GC yeah you could uh find the + + align:start position:0% +GC yeah you could uh find the + + + align:start position:0% +GC yeah you could uh find the +gcd of uh M1 Prime and + + align:start position:0% +gcd of uh M1 Prime and + + + align:start position:0% +gcd of uh M1 Prime and +M2 Prime um I've intercepted those two + + align:start position:0% +M2 Prime um I've intercepted those two + + + align:start position:0% +M2 Prime um I've intercepted those two +now M1 is a prime number K is a prime + + align:start position:0% +now M1 is a prime number K is a prime + + + align:start position:0% +now M1 is a prime number K is a prime +number M2 is a prime number K is a prime + + align:start position:0% +number M2 is a prime number K is a prime + + + align:start position:0% +number M2 is a prime number K is a prime +number here also right so they are all + + align:start position:0% +number here also right so they are all + + + align:start position:0% +number here also right so they are all +uh relatively prime towards one another + + align:start position:0% +uh relatively prime towards one another + + + align:start position:0% +uh relatively prime towards one another +the gcd of these + + align:start position:0% +the gcd of these + + + align:start position:0% +the gcd of these +two well the greatest common divisor is + + align:start position:0% +two well the greatest common divisor is + + + align:start position:0% +two well the greatest common divisor is +K so just by calculating the gcd of the + + align:start position:0% +K so just by calculating the gcd of the + + + align:start position:0% +K so just by calculating the gcd of the +two encrypted messages I will be able to + + align:start position:0% +two encrypted messages I will be able to + + + align:start position:0% +two encrypted messages I will be able to +figure out what uh K is the key so + + align:start position:0% +figure out what uh K is the key so + + + align:start position:0% +figure out what uh K is the key so +that's uh well if I know the key then I + + align:start position:0% +that's uh well if I know the key then I + + + align:start position:0% +that's uh well if I know the key then I +can do the decryption of any Cipher text + + align:start position:0% +can do the decryption of any Cipher text + + + align:start position:0% +can do the decryption of any Cipher text +any encryption of a message that that I + + align:start position:0% +any encryption of a message that that I + + + align:start position:0% +any encryption of a message that that I +can intercept so this is not + + align:start position:0% +can intercept so this is not + + + align:start position:0% +can intercept so this is not +secure so how can we uh change this can + + align:start position:0% +secure so how can we uh change this can + + + align:start position:0% +secure so how can we uh change this can +we uh create a different kind of uh um + + align:start position:0% +we uh create a different kind of uh um + + + align:start position:0% +we uh create a different kind of uh um +encryption + + align:start position:0% +encryption + + + align:start position:0% +encryption +scheme let's do something much more uh + + align:start position:0% +scheme let's do something much more uh + + + align:start position:0% +scheme let's do something much more uh +difficult and uh and then we will get + + align:start position:0% +difficult and uh and then we will get + + + align:start position:0% +difficult and uh and then we will get +into to modular arithmetic and things + + align:start position:0% +into to modular arithmetic and things + + + align:start position:0% +into to modular arithmetic and things +like that so let's do this + + align:start position:0% + + + + align:start position:0% + +um so during code version number + + align:start position:0% +um so during code version number + + + align:start position:0% +um so during code version number +two we try to do something much more + + align:start position:0% +two we try to do something much more + + + align:start position:0% +two we try to do something much more +comp complicated than just multiplying + + align:start position:0% +comp complicated than just multiplying + + + align:start position:0% +comp complicated than just multiplying +by Prime so let's do the + + align:start position:0% +by Prime so let's do the + + + align:start position:0% +by Prime so let's do the +following so + + align:start position:0% +following so + + + align:start position:0% +following so +beforehand uh we are going to exchange a + + align:start position:0% +beforehand uh we are going to exchange a + + + align:start position:0% +beforehand uh we are going to exchange a +uh uh not only a secret Prime K but we + + align:start position:0% +uh uh not only a secret Prime K but we + + + align:start position:0% +uh uh not only a secret Prime K but we +also exchange uh a public + + align:start position:0% +also exchange uh a public + + + align:start position:0% +also exchange uh a public +Prime so we + + align:start position:0% +Prime so we + + + align:start position:0% +Prime so we +exchange uh by public we mean that + + align:start position:0% +exchange uh by public we mean that + + + align:start position:0% +exchange uh by public we mean that +anybody can see this Prime it's it's + + align:start position:0% +anybody can see this Prime it's it's + + + align:start position:0% +anybody can see this Prime it's it's +it's common knowledge a public + + align:start position:0% +it's common knowledge a public + + + align:start position:0% +it's common knowledge a public +Prime + + align:start position:0% +Prime + + + align:start position:0% +Prime +p and also uh a + + align:start position:0% + + + + align:start position:0% + +secret + + align:start position:0% +secret + + + align:start position:0% +secret +Prime okay well let's see whether this + + align:start position:0% +Prime okay well let's see whether this + + + align:start position:0% +Prime okay well let's see whether this +would + + align:start position:0% +would + + + align:start position:0% +would +work um we have an encryption + + align:start position:0% + + + + align:start position:0% + +well we going to start out exactly the + + align:start position:0% +well we going to start out exactly the + + + align:start position:0% +well we going to start out exactly the +same way um uh oh first of all I should + + align:start position:0% +same way um uh oh first of all I should + + + align:start position:0% +same way um uh oh first of all I should +tell you how a message is represented a + + align:start position:0% +tell you how a message is represented a + + + align:start position:0% +tell you how a message is represented a +message is going to be represented as a + + align:start position:0% +message is going to be represented as a + + + align:start position:0% +message is going to be represented as a +number + + align:start position:0% +number + + + align:start position:0% +number +um m in the range from 0 1 all the way + + align:start position:0% +um m in the range from 0 1 all the way + + + align:start position:0% +um m in the range from 0 1 all the way +to P minus + + align:start position:0% +to P minus + + + align:start position:0% +to P minus +one + + align:start position:0% +one + + + align:start position:0% +one +and we will compute the encryption as + + align:start position:0% +and we will compute the encryption as + + + align:start position:0% +and we will compute the encryption as +follows uh M uh is going to be the + + align:start position:0% +follows uh M uh is going to be the + + + align:start position:0% +follows uh M uh is going to be the +remainder of M * K after dividing out as + + align:start position:0% +remainder of M * K after dividing out as + + + align:start position:0% +remainder of M * K after dividing out as +many multiples of p as possible so + + align:start position:0% +many multiples of p as possible so + + + align:start position:0% +many multiples of p as possible so +notice we do kind of the same thing we + + align:start position:0% +notice we do kind of the same thing we + + + align:start position:0% +notice we do kind of the same thing we +just multiply by K but now we just uh um + + align:start position:0% +just multiply by K but now we just uh um + + + align:start position:0% +just multiply by K but now we just uh um +take the remainder after taking out as + + align:start position:0% +take the remainder after taking out as + + + align:start position:0% +take the remainder after taking out as +many multiples of + + align:start position:0% +many multiples of + + + align:start position:0% +many multiples of +P um well let's see whether we can do + + align:start position:0% +P um well let's see whether we can do + + + align:start position:0% +P um well let's see whether we can do +the + + align:start position:0% +the + + + align:start position:0% +the +decryption it seems to be + + align:start position:0% +decryption it seems to be + + + align:start position:0% +decryption it seems to be +like a next level of complexity so maybe + + align:start position:0% +like a next level of complexity so maybe + + + align:start position:0% +like a next level of complexity so maybe +that will help us here + + align:start position:0% +that will help us here + + + align:start position:0% +that will help us here +right so how would we do decryption well + + align:start position:0% +right so how would we do decryption well + + + align:start position:0% +right so how would we do decryption well +somehow we would like to divide by K but + + align:start position:0% +somehow we would like to divide by K but + + + align:start position:0% +somehow we would like to divide by K but +we cannot really do that right um this + + align:start position:0% +we cannot really do that right um this + + + align:start position:0% +we cannot really do that right um this +does not make any + + align:start position:0% +does not make any + + + align:start position:0% +does not make any +sense so the decryption we have no idea + + align:start position:0% +sense so the decryption we have no idea + + + align:start position:0% +sense so the decryption we have no idea +at this point how to do this and um now + + align:start position:0% +at this point how to do this and um now + + + align:start position:0% +at this point how to do this and um now +we can get into modular arithmetic + + align:start position:0% +we can get into modular arithmetic + + + align:start position:0% +we can get into modular arithmetic +because it turns out that we can sort of + + align:start position:0% +because it turns out that we can sort of + + + align:start position:0% +because it turns out that we can sort of +divide by K there exists a what we call + + align:start position:0% +divide by K there exists a what we call + + + align:start position:0% +divide by K there exists a what we call +multiplicative inverse of k modulo p and + + align:start position:0% +multiplicative inverse of k modulo p and + + + align:start position:0% +multiplicative inverse of k modulo p and +I will explain all those terminology to + + align:start position:0% +I will explain all those terminology to + + + align:start position:0% +I will explain all those terminology to +you and um then we will be able to take + + align:start position:0% +you and um then we will be able to take + + + align:start position:0% +you and um then we will be able to take +M Prime and transform it back to M so we + + align:start position:0% +M Prime and transform it back to M so we + + + align:start position:0% +M Prime and transform it back to M so we +will be able to get a lot of this + + align:start position:0% +will be able to get a lot of this + + + align:start position:0% +will be able to get a lot of this +Machinery um going so let's uh find out + + align:start position:0% +Machinery um going so let's uh find out + + + align:start position:0% +Machinery um going so let's uh find out +how this works uh so first of all last + + align:start position:0% +how this works uh so first of all last + + + align:start position:0% +how this works uh so first of all last +time we saw that um uh we defined A and + + align:start position:0% +time we saw that um uh we defined A and + + + align:start position:0% +time we saw that um uh we defined A and +B to be relative relatively prime so let + + align:start position:0% +B to be relative relatively prime so let + + + align:start position:0% +B to be relative relatively prime so let +me repeat + + align:start position:0% +me repeat + + + align:start position:0% +me repeat +that so A are relatively + + align:start position:0% +that so A are relatively + + + align:start position:0% +that so A are relatively +prime um if and only if that's how we + + align:start position:0% +prime um if and only if that's how we + + + align:start position:0% +prime um if and only if that's how we +defined it if the gcd of A and B is + + align:start position:0% +defined it if the gcd of A and B is + + + align:start position:0% +defined it if the gcd of A and B is +equal to one and in last lecture and in + + align:start position:0% +equal to one and in last lecture and in + + + align:start position:0% +equal to one and in last lecture and in +the recitation got a difference proof I + + align:start position:0% +the recitation got a difference proof I + + + align:start position:0% +the recitation got a difference proof I +think um we proved that + + align:start position:0% +think um we proved that + + + align:start position:0% +think um we proved that +actually uh the gcd of A and B is equal + + align:start position:0% +actually uh the gcd of A and B is equal + + + align:start position:0% +actually uh the gcd of A and B is equal +to the smallest positive linear + + align:start position:0% +to the smallest positive linear + + + align:start position:0% +to the smallest positive linear +combination of a and B so that means + + align:start position:0% +combination of a and B so that means + + + align:start position:0% +combination of a and B so that means +that one in particular is a linear + + align:start position:0% +that one in particular is a linear + + + align:start position:0% +that one in particular is a linear +combination of A and B so there exists + + align:start position:0% +combination of A and B so there exists + + + align:start position:0% +combination of A and B so there exists +inures s and t such that s * a + T * b = + + align:start position:0% +inures s and t such that s * a + T * b = + + + align:start position:0% +inures s and t such that s * a + T * b = +1 it turns out that we can also go the + + align:start position:0% +1 it turns out that we can also go the + + + align:start position:0% +1 it turns out that we can also go the +other way around + + align:start position:0% +other way around + + + align:start position:0% +other way around +because if I can write one as a linear + + align:start position:0% +because if I can write one as a linear + + + align:start position:0% +because if I can write one as a linear +combination of A and B well I cannot get + + align:start position:0% +combination of A and B well I cannot get + + + align:start position:0% +combination of A and B well I cannot get +much lower than that right so that's + + align:start position:0% +much lower than that right so that's + + + align:start position:0% +much lower than that right so that's +really the smallest possible that I can + + align:start position:0% +really the smallest possible that I can + + + align:start position:0% +really the smallest possible that I can +achieve so the gcd must be equal to one + + align:start position:0% +achieve so the gcd must be equal to one + + + align:start position:0% +achieve so the gcd must be equal to one +so this is a property that we will be + + align:start position:0% + + + + align:start position:0% + +using + + align:start position:0% +using + + + align:start position:0% +using +um and uh from this property we can + + align:start position:0% +um and uh from this property we can + + + align:start position:0% +um and uh from this property we can +already figure out an interesting + + align:start position:0% +already figure out an interesting + + + align:start position:0% +already figure out an interesting +property so suppose we have a linear + + align:start position:0% +property so suppose we have a linear + + + align:start position:0% +property so suppose we have a linear +combination that looks like this then + + align:start position:0% +combination that looks like this then + + + align:start position:0% +combination that looks like this then +you can imagine that uh sort of that s * + + align:start position:0% +you can imagine that uh sort of that s * + + + align:start position:0% +you can imagine that uh sort of that s * +a is equal to one plus or minus some + + align:start position:0% +a is equal to one plus or minus some + + + align:start position:0% +a is equal to one plus or minus some +linear a multiple of + + align:start position:0% +linear a multiple of + + + align:start position:0% +linear a multiple of +B so it's sort of s * a sort of equal to + + align:start position:0% +B so it's sort of s * a sort of equal to + + + align:start position:0% +B so it's sort of s * a sort of equal to +one you can say up to a multiple of B so + + align:start position:0% +one you can say up to a multiple of B so + + + align:start position:0% +one you can say up to a multiple of B so +um you can see a sort of as an inverse + + align:start position:0% +um you can see a sort of as an inverse + + + align:start position:0% +um you can see a sort of as an inverse +of s because s * a is equal to one sort + + align:start position:0% +of s because s * a is equal to one sort + + + align:start position:0% +of s because s * a is equal to one sort +of so this is what we're going to use + + align:start position:0% +of so this is what we're going to use + + + align:start position:0% +of so this is what we're going to use +this kind of feeling and um in order to + + align:start position:0% +this kind of feeling and um in order to + + + align:start position:0% +this kind of feeling and um in order to +do that we are going to Define uh + + align:start position:0% +do that we are going to Define uh + + + align:start position:0% +do that we are going to Define uh +congruency + + align:start position:0% +congruency + + + align:start position:0% +congruency +um so that's the first definition for + + align:start position:0% +um so that's the first definition for + + + align:start position:0% +um so that's the first definition for +this lecture uh we say X is uh + + align:start position:0% + + + + align:start position:0% + +congruent uh to y + + align:start position:0% +congruent uh to y + + + align:start position:0% +congruent uh to y +modulo + + align:start position:0% +modulo + + + align:start position:0% +modulo +n um + + align:start position:0% +n um + + + align:start position:0% +n um +if which we denote as follows x with + + align:start position:0% +if which we denote as follows x with + + + align:start position:0% +if which we denote as follows x with +three + + align:start position:0% +three + + + align:start position:0% +three +bars Y in between brackets mod + + align:start position:0% +bars Y in between brackets mod + + + align:start position:0% +bars Y in between brackets mod +n and uh we say that this is the case uh + + align:start position:0% +n and uh we say that this is the case uh + + + align:start position:0% +n and uh we say that this is the case uh +if um + + align:start position:0% + + + + align:start position:0% + +n divides the difference between X and Y + + align:start position:0% +n divides the difference between X and Y + + + align:start position:0% +n divides the difference between X and Y +so let's just uh let's have a look at + + align:start position:0% +so let's just uh let's have a look at + + + align:start position:0% +so let's just uh let's have a look at +some + + align:start position:0% +some + + + align:start position:0% +some +examples + + align:start position:0% + + + + align:start position:0% + +um so let's uh take + + align:start position:0% +um so let's uh take + + + align:start position:0% +um so let's uh take +31 and I'll like to show to you that + + align:start position:0% +31 and I'll like to show to you that + + + align:start position:0% +31 and I'll like to show to you that +this is congruent to + + align:start position:0% +this is congruent to + + + align:start position:0% +this is congruent to +16 modulo between brackets uh five why + + align:start position:0% +16 modulo between brackets uh five why + + + align:start position:0% +16 modulo between brackets uh five why +is this well I take the difference + + align:start position:0% +is this well I take the difference + + + align:start position:0% +is this well I take the difference +between 31 and 16 which is 15 and I know + + align:start position:0% +between 31 and 16 which is 15 and I know + + + align:start position:0% +between 31 and 16 which is 15 and I know +that 15 is three times 5 so five divides + + align:start position:0% +that 15 is three times 5 so five divides + + + align:start position:0% +that 15 is three times 5 so five divides +this difference and then by the + + align:start position:0% +this difference and then by the + + + align:start position:0% +this difference and then by the +definition we can write it like this and + + align:start position:0% +definition we can write it like this and + + + align:start position:0% +definition we can write it like this and +we say that's the definition 31 is + + align:start position:0% +we say that's the definition 31 is + + + align:start position:0% +we say that's the definition 31 is +congruent to 16 modul 5 another example + + align:start position:0% +congruent to 16 modul 5 another example + + + align:start position:0% +congruent to 16 modul 5 another example +is + + align:start position:0% +is + + + align:start position:0% +is +um oh no we will stick with this example + + align:start position:0% +um oh no we will stick with this example + + + align:start position:0% +um oh no we will stick with this example +it's pretty clear um so once we have + + align:start position:0% +it's pretty clear um so once we have + + + align:start position:0% +it's pretty clear um so once we have +defined this uh we can continue and uh + + align:start position:0% +defined this uh we can continue and uh + + + align:start position:0% +defined this uh we can continue and uh +talk about this inverse that I was + + align:start position:0% +talk about this inverse that I was + + + align:start position:0% +talk about this inverse that I was +talking about so we like to sort of + + align:start position:0% +talking about so we like to sort of + + + align:start position:0% +talking about so we like to sort of +explain in this encryption scheme uh how + + align:start position:0% +explain in this encryption scheme uh how + + + align:start position:0% +explain in this encryption scheme uh how +we can divide by K actually we would + + align:start position:0% +we can divide by K actually we would + + + align:start position:0% +we can divide by K actually we would +like to multiply by an inverse of K and + + align:start position:0% +like to multiply by an inverse of K and + + + align:start position:0% +like to multiply by an inverse of K and +we're going to use this this framework + + align:start position:0% +we're going to use this this framework + + + align:start position:0% +we're going to use this this framework +so we'll have a new + + align:start position:0% +so we'll have a new + + + align:start position:0% +so we'll have a new +definition that talks about the + + align:start position:0% +definition that talks about the + + + align:start position:0% +definition that talks about the +multiplicative inverse so it's a New + + align:start position:0% +multiplicative inverse so it's a New + + + align:start position:0% +multiplicative inverse so it's a New +Concept + + align:start position:0% +Concept + + + align:start position:0% +Concept +and you'll give a couple of examples so + + align:start position:0% +and you'll give a couple of examples so + + + align:start position:0% +and you'll give a couple of examples so +the + + align:start position:0% + + + + align:start position:0% + +multiplicative + + align:start position:0% +multiplicative + + + align:start position:0% +multiplicative +inverse um of + + align:start position:0% +inverse um of + + + align:start position:0% +inverse um of +X modulo + + align:start position:0% +X modulo + + + align:start position:0% +X modulo +N is a a number which we + + align:start position:0% + + + + align:start position:0% + +denote by X and then minus one on top of + + align:start position:0% +denote by X and then minus one on top of + + + align:start position:0% +denote by X and then minus one on top of +here uh it's a number in the interval 0 + + align:start position:0% +here uh it's a number in the interval 0 + + + align:start position:0% +here uh it's a number in the interval 0 +1 all the way up to n minus + + align:start position:0% +1 all the way up to n minus + + + align:start position:0% +1 all the way up to n minus +one uh such + + align:start position:0% +one uh such + + + align:start position:0% +one uh such +that x * X inverse so x times its + + align:start position:0% +that x * X inverse so x times its + + + align:start position:0% +that x * X inverse so x times its +multiplicative inverse is congruent to + + align:start position:0% +multiplicative inverse is congruent to + + + align:start position:0% +multiplicative inverse is congruent to +One + + align:start position:0% +One + + + align:start position:0% +One +modulo n so this is the definition for a + + align:start position:0% +modulo n so this is the definition for a + + + align:start position:0% +modulo n so this is the definition for a +multiplicative inverse so let's have an + + align:start position:0% +multiplicative inverse so let's have an + + + align:start position:0% +multiplicative inverse so let's have an +uh some + + align:start position:0% + + + + align:start position:0% + +examples um + + align:start position:0% +examples um + + + align:start position:0% +examples um +so let's do that over + + align:start position:0% +so let's do that over + + + align:start position:0% +so let's do that over +here uh for + + align:start position:0% +here uh for + + + align:start position:0% +here uh for +example we have that uh 2 * 3 which + + align:start position:0% +example we have that uh 2 * 3 which + + + align:start position:0% +example we have that uh 2 * 3 which +equals 6 right is equal to 1 modul + + align:start position:0% +equals 6 right is equal to 1 modul + + + align:start position:0% +equals 6 right is equal to 1 modul +5 why is this well uh 6 minus one is + + align:start position:0% +5 why is this well uh 6 minus one is + + + align:start position:0% +5 why is this well uh 6 minus one is +divisible by five so I know that this is + + align:start position:0% +divisible by five so I know that this is + + + align:start position:0% +divisible by five so I know that this is +congruent to one modul 5 so what does + + align:start position:0% +congruent to one modul 5 so what does + + + align:start position:0% +congruent to one modul 5 so what does +this + + align:start position:0% +this + + + align:start position:0% +this +mean uh well we can say that two is + + align:start position:0% +mean uh well we can say that two is + + + align:start position:0% +mean uh well we can say that two is +actually equal to the multiplicative + + align:start position:0% +actually equal to the multiplicative + + + align:start position:0% +actually equal to the multiplicative +inverse of + + align:start position:0% +inverse of + + + align:start position:0% +inverse of +three modul 5 uh we can also say that uh + + align:start position:0% +three modul 5 uh we can also say that uh + + + align:start position:0% +three modul 5 uh we can also say that uh +right that three is the multiplicative + + align:start position:0% +right that three is the multiplicative + + + align:start position:0% +right that three is the multiplicative +inverse of two modul + + align:start position:0% +inverse of two modul + + + align:start position:0% +inverse of two modul +5 let's have another example uh just to + + align:start position:0% +5 let's have another example uh just to + + + align:start position:0% +5 let's have another example uh just to +make it a little bit more + + align:start position:0% +make it a little bit more + + + align:start position:0% +make it a little bit more +clear we know that 5 * 5 equals 25 and + + align:start position:0% +clear we know that 5 * 5 equals 25 and + + + align:start position:0% +clear we know that 5 * 5 equals 25 and +this is congruent to one modulo uh 6 + + align:start position:0% +this is congruent to one modulo uh 6 + + + align:start position:0% +this is congruent to one modulo uh 6 +because because 25 is 1 + 4 * + + align:start position:0% +because because 25 is 1 + 4 * + + + align:start position:0% +because because 25 is 1 + 4 * +6 so now we see something funny + + align:start position:0% +6 so now we see something funny + + + align:start position:0% +6 so now we see something funny +happening because 5 is actually equal to + + align:start position:0% +happening because 5 is actually equal to + + + align:start position:0% +happening because 5 is actually equal to +its own multiplicative inverse modul + + align:start position:0% + + + + align:start position:0% + + + align:start position:0% + + + align:start position:0% +so so are there any questions about + + align:start position:0% +so so are there any questions about + + + align:start position:0% +so so are there any questions about +these Concepts because these are really + + align:start position:0% +these Concepts because these are really + + + align:start position:0% +these Concepts because these are really +basic for the whole lecture and this is + + align:start position:0% +basic for the whole lecture and this is + + + align:start position:0% +basic for the whole lecture and this is +what you really need to understand if + + align:start position:0% +what you really need to understand if + + + align:start position:0% +what you really need to understand if +you do all the problem sets as well + + align:start position:0% +you do all the problem sets as well + + + align:start position:0% +you do all the problem sets as well +um are there any + + align:start position:0% +um are there any + + + align:start position:0% +um are there any +questions + + align:start position:0% +questions + + + align:start position:0% +questions +so now we can actually start talking + + align:start position:0% +so now we can actually start talking + + + align:start position:0% +so now we can actually start talking +about this uh uh second version of the + + align:start position:0% +about this uh uh second version of the + + + align:start position:0% +about this uh uh second version of the +touring code that we uh uh + + align:start position:0% +touring code that we uh uh + + + align:start position:0% +touring code that we uh uh +invented um let's have a look at this + + align:start position:0% +invented um let's have a look at this + + + align:start position:0% +invented um let's have a look at this +remainder so let's write it out again + + align:start position:0% +remainder so let's write it out again + + + align:start position:0% +remainder so let's write it out again +the remainder of uh M * K after dividing + + align:start position:0% +the remainder of uh M * K after dividing + + + align:start position:0% +the remainder of uh M * K after dividing +out as many multiples of P well we know + + align:start position:0% +out as many multiples of P well we know + + + align:start position:0% +out as many multiples of P well we know +that this is congruent to M * k modul + + align:start position:0% +that this is congruent to M * k modul + + + align:start position:0% +that this is congruent to M * k modul +p so why is this uh well we just apply + + align:start position:0% +p so why is this uh well we just apply + + + align:start position:0% +p so why is this uh well we just apply +the definition over here we take the + + align:start position:0% +the definition over here we take the + + + align:start position:0% +the definition over here we take the +difference between those two so here we + + align:start position:0% +difference between those two so here we + + + align:start position:0% +difference between those two so here we +have the remainder of M * K after + + align:start position:0% +have the remainder of M * K after + + + align:start position:0% +have the remainder of M * K after +dividing out as many multiples of + + align:start position:0% +dividing out as many multiples of + + + align:start position:0% +dividing out as many multiples of +P um and if we subtract that from M * K + + align:start position:0% +P um and if we subtract that from M * K + + + align:start position:0% +P um and if we subtract that from M * K +well then we have something that is a + + align:start position:0% +well then we have something that is a + + + align:start position:0% +well then we have something that is a +multiple of P because that's what we + + align:start position:0% +multiple of P because that's what we + + + align:start position:0% +multiple of P because that's what we +divided out so so the difference is a + + align:start position:0% +divided out so so the difference is a + + + align:start position:0% +divided out so so the difference is a +multiple of P um so that means that P + + align:start position:0% +multiple of P um so that means that P + + + align:start position:0% +multiple of P um so that means that P +divides the difference and that's a + + align:start position:0% +divides the difference and that's a + + + align:start position:0% +divides the difference and that's a +definition of saying that this remainder + + align:start position:0% +definition of saying that this remainder + + + align:start position:0% +definition of saying that this remainder +is congruent to MK modulo P so this is + + align:start position:0% +is congruent to MK modulo P so this is + + + align:start position:0% +is congruent to MK modulo P so this is +kind of interesting because now um we + + align:start position:0% +kind of interesting because now um we + + + align:start position:0% +kind of interesting because now um we +can rewrite over there uh well not + + align:start position:0% +can rewrite over there uh well not + + + align:start position:0% +can rewrite over there uh well not +really rewrite but we can uh use this to + + align:start position:0% +really rewrite but we can uh use this to + + + align:start position:0% +really rewrite but we can uh use this to +analyze the encryption over here so M + + align:start position:0% +analyze the encryption over here so M + + + align:start position:0% +analyze the encryption over here so M +Prime is equal to this uh remainder and + + align:start position:0% +Prime is equal to this uh remainder and + + + align:start position:0% +Prime is equal to this uh remainder and +we get a beautiful equation we see that + + align:start position:0% +we get a beautiful equation we see that + + + align:start position:0% +we get a beautiful equation we see that +the encryption is congruent to the plain + + align:start position:0% +the encryption is congruent to the plain + + + align:start position:0% +the encryption is congruent to the plain +message times the key modulo P so how do + + align:start position:0% +message times the key modulo P so how do + + + align:start position:0% +message times the key modulo P so how do +I do decryption I can use the + + align:start position:0% +I do decryption I can use the + + + align:start position:0% +I do decryption I can use the +multiplicative inverse of K right so + + align:start position:0% +multiplicative inverse of K right so + + + align:start position:0% +multiplicative inverse of K right so +then I can divide k out + + align:start position:0% +then I can divide k out + + + align:start position:0% +then I can divide k out +so so let's write this out as well so + + align:start position:0% +so so let's write this out as well so + + + align:start position:0% +so so let's write this out as well so +suppose I have a multiplicative inverse + + align:start position:0% +suppose I have a multiplicative inverse + + + align:start position:0% +suppose I have a multiplicative inverse +K to the^ minus one that that is + + align:start position:0% +K to the^ minus one that that is + + + align:start position:0% +K to the^ minus one that that is +congruent to one modulo + + align:start position:0% +congruent to one modulo + + + align:start position:0% +congruent to one modulo +p why do I do this why why am I writing + + align:start position:0% +p why do I do this why why am I writing + + + align:start position:0% +p why do I do this why why am I writing +this out because uh we will see that it + + align:start position:0% +this out because uh we will see that it + + + align:start position:0% +this out because uh we will see that it +is not always possible to have a + + align:start position:0% +is not always possible to have a + + + align:start position:0% +is not always possible to have a +multiplicative inverse that's going to + + align:start position:0% +multiplicative inverse that's going to + + + align:start position:0% +multiplicative inverse that's going to +be really a big problem and that's uh + + align:start position:0% +be really a big problem and that's uh + + + align:start position:0% +be really a big problem and that's uh +where uh all these other um functions + + align:start position:0% +where uh all these other um functions + + + align:start position:0% +where uh all these other um functions +come in the ear toan function and ear + + align:start position:0% +come in the ear toan function and ear + + + align:start position:0% +come in the ear toan function and ear +theorem and so on so it's not really + + align:start position:0% +theorem and so on so it's not really + + + align:start position:0% +theorem and so on so it's not really +always the case we'll give an example in + + align:start position:0% +always the case we'll give an example in + + + align:start position:0% +always the case we'll give an example in +a moment but suppose that we have a + + align:start position:0% +a moment but suppose that we have a + + + align:start position:0% +a moment but suppose that we have a +multiplicative inverse modulo P well + + align:start position:0% +multiplicative inverse modulo P well + + + align:start position:0% +multiplicative inverse modulo P well +then I'm able to easily compute well I + + align:start position:0% +then I'm able to easily compute well I + + + align:start position:0% +then I'm able to easily compute well I +take M Prime I multiply it with K + + align:start position:0% +take M Prime I multiply it with K + + + align:start position:0% +take M Prime I multiply it with K +inverse well this is I'm substituting + + align:start position:0% +inverse well this is I'm substituting + + + align:start position:0% +inverse well this is I'm substituting +for M Prime M * + + align:start position:0% + + + + align:start position:0% + +K time K inverse I still have this left + + align:start position:0% +K time K inverse I still have this left + + + align:start position:0% +K time K inverse I still have this left +now I can say that those that this is + + align:start position:0% +now I can say that those that this is + + + align:start position:0% +now I can say that those that this is +equal to uh 1 modulo + + align:start position:0% +equal to uh 1 modulo + + + align:start position:0% +equal to uh 1 modulo +P so this is equal or is congruent to m + + align:start position:0% +P so this is equal or is congruent to m + + + align:start position:0% +P so this is equal or is congruent to m +modulo p so now we see how we can do + + align:start position:0% +modulo p so now we see how we can do + + + align:start position:0% +modulo p so now we see how we can do +decryption we simply use the + + align:start position:0% +decryption we simply use the + + + align:start position:0% +decryption we simply use the +multiplicative inverse of K and as in + + align:start position:0% +multiplicative inverse of K and as in + + + align:start position:0% +multiplicative inverse of K and as in +the first uh touring code we are able to + + align:start position:0% +the first uh touring code we are able to + + + align:start position:0% +the first uh touring code we are able to +somehow uh divide out so where did I + + align:start position:0% +somehow uh divide out so where did I + + + align:start position:0% +somehow uh divide out so where did I +have it to divide out k i I did it very + + align:start position:0% +have it to divide out k i I did it very + + + align:start position:0% +have it to divide out k i I did it very +differently have a very different + + align:start position:0% +differently have a very different + + + align:start position:0% +differently have a very different +mathematical structure but but uh the + + align:start position:0% +mathematical structure but but uh the + + + align:start position:0% +mathematical structure but but uh the +idea is essentially the same I have a + + align:start position:0% +idea is essentially the same I have a + + + align:start position:0% +idea is essentially the same I have a +multiplicative inverse of K and If I + + align:start position:0% +multiplicative inverse of K and If I + + + align:start position:0% +multiplicative inverse of K and If I +multiply this with the encryption I will + + align:start position:0% +multiply this with the encryption I will + + + align:start position:0% +multiply this with the encryption I will +get the plain message modulo P so am I + + align:start position:0% +get the plain message modulo P so am I + + + align:start position:0% +get the plain message modulo P so am I +finished now is the question well uh I + + align:start position:0% +finished now is the question well uh I + + + align:start position:0% +finished now is the question well uh I +know that m is in the range uh of 01 all + + align:start position:0% +know that m is in the range uh of 01 all + + + align:start position:0% +know that m is in the range uh of 01 all +the way up to P minus + + align:start position:0% +the way up to P minus + + + align:start position:0% +the way up to P minus +one so um this means that I can also + + align:start position:0% +one so um this means that I can also + + + align:start position:0% +one so um this means that I can also +rewrite m s and I use a similar trick as + + align:start position:0% +rewrite m s and I use a similar trick as + + + align:start position:0% +rewrite m s and I use a similar trick as +what I did over here I can rewrite M as + + align:start position:0% +what I did over here I can rewrite M as + + + align:start position:0% +what I did over here I can rewrite M as +the + + align:start position:0% +the + + + align:start position:0% +the +remainder of M Prime * K + + align:start position:0% +remainder of M Prime * K + + + align:start position:0% +remainder of M Prime * K +inverse after dividing out as many + + align:start position:0% +inverse after dividing out as many + + + align:start position:0% +inverse after dividing out as many +copies of p as + + align:start position:0% +copies of p as + + + align:start position:0% +copies of p as +possible so what we did here is to First + + align:start position:0% +possible so what we did here is to First + + + align:start position:0% +possible so what we did here is to First +prove that the difference between those + + align:start position:0% +prove that the difference between those + + + align:start position:0% +prove that the difference between those +two is a multiple of P that's + + align:start position:0% +two is a multiple of P that's + + + align:start position:0% +two is a multiple of P that's +essentially what congruent modulo p + + align:start position:0% +essentially what congruent modulo p + + + align:start position:0% +essentially what congruent modulo p +means that's the definition + + align:start position:0% +means that's the definition + + + align:start position:0% +means that's the definition +so now that I know that the difference + + align:start position:0% +so now that I know that the difference + + + align:start position:0% +so now that I know that the difference +is a multiple of P um and if I know that + + align:start position:0% +is a multiple of P um and if I know that + + + align:start position:0% +is a multiple of P um and if I know that +m is actually in this range up to P + + align:start position:0% +m is actually in this range up to P + + + align:start position:0% +m is actually in this range up to P +minus one I can use what we learned uh + + align:start position:0% +minus one I can use what we learned uh + + + align:start position:0% +minus one I can use what we learned uh +last lecture and what the book was + + align:start position:0% +last lecture and what the book was + + + align:start position:0% +last lecture and what the book was +talking about that the definition of the + + align:start position:0% +talking about that the definition of the + + + align:start position:0% +talking about that the definition of the +remainder of M Prime * K inverse this + + align:start position:0% +remainder of M Prime * K inverse this + + + align:start position:0% +remainder of M Prime * K inverse this +thing after finding out as many copies + + align:start position:0% +thing after finding out as many copies + + + align:start position:0% +thing after finding out as many copies +of p is exactly this plain message M + + align:start position:0% +of p is exactly this plain message M + + + align:start position:0% +of p is exactly this plain message M +okay so now we have the decryption so + + align:start position:0% +okay so now we have the decryption so + + + align:start position:0% +okay so now we have the decryption so +this is decryption + + align:start position:0% + + + + align:start position:0% + +and uh that sounds great so now of + + align:start position:0% +and uh that sounds great so now of + + + align:start position:0% +and uh that sounds great so now of +course we are wondering uh well if we uh + + align:start position:0% +course we are wondering uh well if we uh + + + align:start position:0% +course we are wondering uh well if we uh +can do this can we also uh attack this + + align:start position:0% +can do this can we also uh attack this + + + align:start position:0% +can do this can we also uh attack this +scheme right can we do something bad + + align:start position:0% +scheme right can we do something bad + + + align:start position:0% +scheme right can we do something bad +with it um well it can be used to break + + align:start position:0% +with it um well it can be used to break + + + align:start position:0% +with it um well it can be used to break +this code but in a slightly more uh + + align:start position:0% +this code but in a slightly more uh + + + align:start position:0% +this code but in a slightly more uh +complicated way + + align:start position:0% +complicated way + + + align:start position:0% +complicated way +um so let's see where I put that + + align:start position:0% +um so let's see where I put that + + + align:start position:0% +um so let's see where I put that +right so what we're going to use now uh + + align:start position:0% +right so what we're going to use now uh + + + align:start position:0% +right so what we're going to use now uh +so when we talk about security and so on + + align:start position:0% +so when we talk about security and so on + + + align:start position:0% +so when we talk about security and so on +uh you can think of all kinds of ways to + + align:start position:0% +uh you can think of all kinds of ways to + + + align:start position:0% +uh you can think of all kinds of ways to +break uh an encryption scheme so we + + align:start position:0% +break uh an encryption scheme so we + + + align:start position:0% +break uh an encryption scheme so we +started out with in the first version + + align:start position:0% +started out with in the first version + + + align:start position:0% +started out with in the first version +well what if I just know the encryption + + align:start position:0% +well what if I just know the encryption + + + align:start position:0% +well what if I just know the encryption +and then um well I cannot know anything + + align:start position:0% +and then um well I cannot know anything + + + align:start position:0% +and then um well I cannot know anything +about the pl Tech simply because I know + + align:start position:0% +about the pl Tech simply because I know + + + align:start position:0% +about the pl Tech simply because I know +it's very hard to factor to factor a + + align:start position:0% +it's very hard to factor to factor a + + + align:start position:0% +it's very hard to factor to factor a +product of two large primes then I said + + align:start position:0% +product of two large primes then I said + + + align:start position:0% +product of two large primes then I said +but I can know a little bit more as an + + align:start position:0% +but I can know a little bit more as an + + + align:start position:0% +but I can know a little bit more as an +adversary suppose I have a plane message + + align:start position:0% +adversary suppose I have a plane message + + + align:start position:0% +adversary suppose I have a plane message +together with a uh um encrypted message + + align:start position:0% +together with a uh um encrypted message + + + align:start position:0% +together with a uh um encrypted message +well then I could do this gcd trick and + + align:start position:0% +well then I could do this gcd trick and + + + align:start position:0% +well then I could do this gcd trick and +figure out and break the scheme and now + + align:start position:0% +figure out and break the scheme and now + + + align:start position:0% +figure out and break the scheme and now +we're going to do something similar and + + align:start position:0% +we're going to do something similar and + + + align:start position:0% +we're going to do something similar and +we say well suppose + + align:start position:0% +we say well suppose + + + align:start position:0% +we say well suppose +um uh that I do not know two encryptions + + align:start position:0% +um uh that I do not know two encryptions + + + align:start position:0% +um uh that I do not know two encryptions +but I know uh a plain message and an + + align:start position:0% +but I know uh a plain message and an + + + align:start position:0% +but I know uh a plain message and an +corresponding encrypted message message + + align:start position:0% +corresponding encrypted message message + + + align:start position:0% +corresponding encrypted message message +so if I know such a pair which is I mean + + align:start position:0% +so if I know such a pair which is I mean + + + align:start position:0% +so if I know such a pair which is I mean +in practice such such type of + + align:start position:0% +in practice such such type of + + + align:start position:0% +in practice such such type of +information will be leaked um then in + + align:start position:0% +information will be leaked um then in + + + align:start position:0% +information will be leaked um then in +this case I can break it so we call this + + align:start position:0% +this case I can break it so we call this + + + align:start position:0% +this case I can break it so we call this +the known uh plain text + + align:start position:0% +the known uh plain text + + + align:start position:0% +the known uh plain text +attack and + + align:start position:0% +attack and + + + align:start position:0% +attack and +um it assumes that uh we know as an + + align:start position:0% +um it assumes that uh we know as an + + + align:start position:0% +um it assumes that uh we know as an +adversary I + + align:start position:0% +adversary I + + + align:start position:0% +adversary I +know a a message a plain + + align:start position:0% +know a a message a plain + + + align:start position:0% +know a a message a plain +message m + + align:start position:0% +message m + + + align:start position:0% +message m +and also an encryption of this + + align:start position:0% + + + + align:start position:0% + +message + + align:start position:0% +message + + + align:start position:0% +message +um M Prime and M Prime according to this + + align:start position:0% +um M Prime and M Prime according to this + + + align:start position:0% +um M Prime and M Prime according to this +scheme is the remainder of M * K after + + align:start position:0% +scheme is the remainder of M * K after + + + align:start position:0% +scheme is the remainder of M * K after +dividing out as many multiples of p as + + align:start position:0% +dividing out as many multiples of p as + + + align:start position:0% +dividing out as many multiples of p as +possible now we saw um now suppose I + + align:start position:0% +possible now we saw um now suppose I + + + align:start position:0% +possible now we saw um now suppose I +know these two I'm going to show to you + + align:start position:0% +know these two I'm going to show to you + + + align:start position:0% +know these two I'm going to show to you +how to break it so let's have a look M + + align:start position:0% +how to break it so let's have a look M + + + align:start position:0% +how to break it so let's have a look M +uh the the encryption M Prime here is + + align:start position:0% +uh the the encryption M Prime here is + + + align:start position:0% +uh the the encryption M Prime here is +congruent to M * k modulo p you just + + align:start position:0% +congruent to M * k modulo p you just + + + align:start position:0% +congruent to M * k modulo p you just +proved it over + + align:start position:0% +proved it over + + + align:start position:0% +proved it over +here and uh what do we know we know that + + align:start position:0% +here and uh what do we know we know that + + + align:start position:0% +here and uh what do we know we know that +P is a public Prime I know + + align:start position:0% +P is a public Prime I know + + + align:start position:0% +P is a public Prime I know +P since it's a prime I know that the gcd + + align:start position:0% +P since it's a prime I know that the gcd + + + align:start position:0% +P since it's a prime I know that the gcd +of M and P equals + + align:start position:0% +of M and P equals + + + align:start position:0% +of M and P equals +one so these two are relatively prime so + + align:start position:0% +one so these two are relatively prime so + + + align:start position:0% +one so these two are relatively prime so +now if they're relatively prime time and + + align:start position:0% +now if they're relatively prime time and + + + align:start position:0% +now if they're relatively prime time and +that's what we wrote up here we know + + align:start position:0% +that's what we wrote up here we know + + + align:start position:0% +that's what we wrote up here we know +that there exists this linear + + align:start position:0% +that there exists this linear + + + align:start position:0% +that there exists this linear +combination of uh in this case uh M and + + align:start position:0% +combination of uh in this case uh M and + + + align:start position:0% +combination of uh in this case uh M and +M and P uh that is equal to + + align:start position:0% +M and P uh that is equal to + + + align:start position:0% +M and P uh that is equal to +one and in this way we can figure out + + align:start position:0% +one and in this way we can figure out + + + align:start position:0% +one and in this way we can figure out +how to compute uh the inverse the + + align:start position:0% +how to compute uh the inverse the + + + align:start position:0% +how to compute uh the inverse the +multiplicative inverse of + + align:start position:0% +multiplicative inverse of + + + align:start position:0% +multiplicative inverse of +M so that's what we're going to do so we + + align:start position:0% +M so that's what we're going to do so we + + + align:start position:0% +M so that's what we're going to do so we +can + + align:start position:0% +can + + + align:start position:0% +can +compute um the multiplicative + + align:start position:0% +compute um the multiplicative + + + align:start position:0% +compute um the multiplicative +inverse uh such that M * m inverse is + + align:start position:0% +inverse uh such that M * m inverse is + + + align:start position:0% +inverse uh such that M * m inverse is +congruent to one + + align:start position:0% +congruent to one + + + align:start position:0% +congruent to one +modulo + + align:start position:0% + + + + align:start position:0% + +p so now we can do the next step uh so + + align:start position:0% +p so now we can do the next step uh so + + + align:start position:0% +p so now we can do the next step uh so +what could I do next so let's see if I + + align:start position:0% +what could I do next so let's see if I + + + align:start position:0% +what could I do next so let's see if I +have such an + + align:start position:0% +have such an + + + align:start position:0% +have such an +inverse then I can take my uh encrypted + + align:start position:0% +inverse then I can take my uh encrypted + + + align:start position:0% +inverse then I can take my uh encrypted +uh message that I have as an attacker + + align:start position:0% +uh message that I have as an attacker + + + align:start position:0% +uh message that I have as an attacker +which is M Prime + + align:start position:0% +which is M Prime + + + align:start position:0% +which is M Prime +time um I Know M and since P was public + + align:start position:0% +time um I Know M and since P was public + + + align:start position:0% +time um I Know M and since P was public +I can compute this multiplicative + + align:start position:0% +I can compute this multiplicative + + + align:start position:0% +I can compute this multiplicative +inverse so I can just compute + + align:start position:0% +inverse so I can just compute + + + align:start position:0% +inverse so I can just compute +this uh product and I know that this is + + align:start position:0% +this uh product and I know that this is + + + align:start position:0% +this uh product and I know that this is +actually equal to well K * m * m inverse + + align:start position:0% +actually equal to well K * m * m inverse + + + align:start position:0% +actually equal to well K * m * m inverse +this is again equal to congruent to one + + align:start position:0% +this is again equal to congruent to one + + + align:start position:0% +this is again equal to congruent to one +modul p so this is equal to K + + align:start position:0% +modul p so this is equal to K + + + align:start position:0% +modul p so this is equal to K +modul so now all of a sudden I know k + + align:start position:0% +modul so now all of a sudden I know k + + + align:start position:0% +modul so now all of a sudden I know k +modulo P because I know those two so if + + align:start position:0% +modulo P because I know those two so if + + + align:start position:0% +modulo P because I know those two so if +I know k i can + + align:start position:0% +I know k i can + + + align:start position:0% +I know k i can +compute its multiplicative inverse so I + + align:start position:0% +compute its multiplicative inverse so I + + + align:start position:0% +compute its multiplicative inverse so I +can compute K inverse uh modulo + + align:start position:0% +can compute K inverse uh modulo + + + align:start position:0% +can compute K inverse uh modulo +p and if I know K inverse again I can + + align:start position:0% +p and if I know K inverse again I can + + + align:start position:0% +p and if I know K inverse again I can +use it to decrypt any other uh encrypted + + align:start position:0% +use it to decrypt any other uh encrypted + + + align:start position:0% +use it to decrypt any other uh encrypted +message that I receive so for all future + + align:start position:0% +message that I receive so for all future + + + align:start position:0% +message that I receive so for all future +encrypted messages I do not need anymore + + align:start position:0% +encrypted messages I do not need anymore + + + align:start position:0% +encrypted messages I do not need anymore +the plain messages I have already used + + align:start position:0% +the plain messages I have already used + + + align:start position:0% +the plain messages I have already used +just by using one plain message + + align:start position:0% +just by using one plain message + + + align:start position:0% +just by using one plain message +encryption pair I have been able to + + align:start position:0% +encryption pair I have been able to + + + align:start position:0% +encryption pair I have been able to +compute the secret key and the whole + + align:start position:0% +compute the secret key and the whole + + + align:start position:0% +compute the secret key and the whole +scheme is broken so security and and + + align:start position:0% +scheme is broken so security and and + + + align:start position:0% +scheme is broken so security and and +it's kind of a + + align:start position:0% +it's kind of a + + + align:start position:0% +it's kind of a +interesting uh sence uh we can always + + align:start position:0% +interesting uh sence uh we can always + + + align:start position:0% +interesting uh sence uh we can always +think of more tricks to break schemes or + + align:start position:0% +think of more tricks to break schemes or + + + align:start position:0% +think of more tricks to break schemes or +other + + align:start position:0% +other + + + align:start position:0% +other +assumptions um that we haven't thought + + align:start position:0% +assumptions um that we haven't thought + + + align:start position:0% +assumptions um that we haven't thought +about + + align:start position:0% +about + + + align:start position:0% +about +before um so now let's Let's uh talk + + align:start position:0% +before um so now let's Let's uh talk + + + align:start position:0% +before um so now let's Let's uh talk +about uh so what did we do + + align:start position:0% +about uh so what did we do + + + align:start position:0% +about uh so what did we do +here um we have been talking about uh + + align:start position:0% +here um we have been talking about uh + + + align:start position:0% +here um we have been talking about uh +about encryption this these two schemes + + align:start position:0% +about encryption this these two schemes + + + align:start position:0% +about encryption this these two schemes +we talked about modular + + align:start position:0% +we talked about modular + + + align:start position:0% +we talked about modular +arithmetic talked about congruence and + + align:start position:0% +arithmetic talked about congruence and + + + align:start position:0% +arithmetic talked about congruence and +also the multiplicative inverse and we + + align:start position:0% +also the multiplicative inverse and we + + + align:start position:0% +also the multiplicative inverse and we +showed how to uh use that to break + + align:start position:0% +showed how to uh use that to break + + + align:start position:0% +showed how to uh use that to break +juring scod version number two so we + + align:start position:0% +juring scod version number two so we + + + align:start position:0% +juring scod version number two so we +need something much more fundamental in + + align:start position:0% +need something much more fundamental in + + + align:start position:0% +need something much more fundamental in +order to create a scheme that is really + + align:start position:0% +order to create a scheme that is really + + + align:start position:0% +order to create a scheme that is really +secure and that's what we're going to do + + align:start position:0% +secure and that's what we're going to do + + + align:start position:0% +secure and that's what we're going to do +now we're going to start off with oil's + + align:start position:0% +now we're going to start off with oil's + + + align:start position:0% +now we're going to start off with oil's +toen function and improve a related + + align:start position:0% +toen function and improve a related + + + align:start position:0% +toen function and improve a related +theorem and with that we will be able to + + align:start position:0% +theorem and with that we will be able to + + + align:start position:0% +theorem and with that we will be able to +actually create uh explain the RSA + + align:start position:0% +actually create uh explain the RSA + + + align:start position:0% +actually create uh explain the RSA +algorithm which is a famous algorithm + + align:start position:0% +algorithm which is a famous algorithm + + + align:start position:0% +algorithm which is a famous algorithm +invented here at MIT in 1977 by uh by + + align:start position:0% +invented here at MIT in 1977 by uh by + + + align:start position:0% +invented here at MIT in 1977 by uh by +reest Shamir and adman and uh they + + align:start position:0% +reest Shamir and adman and uh they + + + align:start position:0% +reest Shamir and adman and uh they +actually also got the touring award for + + align:start position:0% +actually also got the touring award for + + + align:start position:0% +actually also got the touring award for +this a few years ago uh um and it's + + align:start position:0% +this a few years ago uh um and it's + + + align:start position:0% +this a few years ago uh um and it's +widely used uh in in + + align:start position:0% +widely used uh in in + + + align:start position:0% +widely used uh in in +practice but we will be able to actually + + align:start position:0% +practice but we will be able to actually + + + align:start position:0% +practice but we will be able to actually +explain this algorithm with just this + + align:start position:0% +explain this algorithm with just this + + + align:start position:0% +explain this algorithm with just this +fundamental piece of number Theory so + + align:start position:0% +fundamental piece of number Theory so + + + align:start position:0% +fundamental piece of number Theory so +that's really exciting so let's do + + align:start position:0% +that's really exciting so let's do + + + align:start position:0% +that's really exciting so let's do +this + + align:start position:0% + + + + align:start position:0% + +um so we're going to first Define uh + + align:start position:0% +um so we're going to first Define uh + + + align:start position:0% +um so we're going to first Define uh +Oilers toan function + + align:start position:0% + + + + align:start position:0% + +and it's related to this multiplicative + + align:start position:0% + + + + align:start position:0% + +inverse this function is uh denoted by F + + align:start position:0% +inverse this function is uh denoted by F + + + align:start position:0% +inverse this function is uh denoted by F +of + + align:start position:0% +of + + + align:start position:0% +of +N + + align:start position:0% +N + + + align:start position:0% +N +and it + + align:start position:0% +and it + + + align:start position:0% +and it +denotes uh the number of + + align:start position:0% + + + + align:start position:0% + +integers number of integers in one 2 3 + + align:start position:0% +integers number of integers in one 2 3 + + + align:start position:0% +integers number of integers in one 2 3 +all the way up to n minus + + align:start position:0% +all the way up to n minus + + + align:start position:0% +all the way up to n minus +one that are relatively + + align:start position:0% + + + + align:start position:0% + +prime that are relatively prime to n + + align:start position:0% + + + + align:start position:0% + +so well this is uh this just drops out + + align:start position:0% +so well this is uh this just drops out + + + align:start position:0% +so well this is uh this just drops out +of the air you may think but um yeah + + align:start position:0% +of the air you may think but um yeah + + + align:start position:0% +of the air you may think but um yeah +this is a a fundamental quantity and + + align:start position:0% +this is a a fundamental quantity and + + + align:start position:0% +this is a a fundamental quantity and +erish Theorem is what we will try to + + align:start position:0% +erish Theorem is what we will try to + + + align:start position:0% +erish Theorem is what we will try to +prove next but let's give a couple of + + align:start position:0% +prove next but let's give a couple of + + + align:start position:0% +prove next but let's give a couple of +examples about this + + align:start position:0% +examples about this + + + align:start position:0% +examples about this +um just to see how it + + align:start position:0% + + + + align:start position:0% + +works so for example let's take n to be + + align:start position:0% +works so for example let's take n to be + + + align:start position:0% +works so for example let's take n to be +equal to + + align:start position:0% +equal to + + + align:start position:0% +equal to +12 um what would be the value of a + + align:start position:0% +12 um what would be the value of a + + + align:start position:0% +12 um what would be the value of a +erosion function evaluated for + + align:start position:0% +erosion function evaluated for + + + align:start position:0% +erosion function evaluated for + + align:start position:0% + + + align:start position:0% +so if you take 12 we have + + align:start position:0% + + + + align:start position:0% + +um the following numbers to consider 1 2 + + align:start position:0% +um the following numbers to consider 1 2 + + + align:start position:0% +um the following numbers to consider 1 2 +3 4 5 6 7 8 9 10 11 and 12 so now let's + + align:start position:0% +3 4 5 6 7 8 9 10 11 and 12 so now let's + + + align:start position:0% +3 4 5 6 7 8 9 10 11 and 12 so now let's +have a look you want to count the N the + + align:start position:0% +have a look you want to count the N the + + + align:start position:0% +have a look you want to count the N the +you want to count the integers that are + + align:start position:0% +you want to count the integers that are + + + align:start position:0% +you want to count the integers that are +relatively prime to to + + align:start position:0% +relatively prime to to + + + align:start position:0% +relatively prime to to +12 um well uh one is relatively prime to + + align:start position:0% +12 um well uh one is relatively prime to + + + align:start position:0% +12 um well uh one is relatively prime to +12 why is that because the gcd of 12 and + + align:start position:0% +12 why is that because the gcd of 12 and + + + align:start position:0% +12 why is that because the gcd of 12 and +one is equal to one and that's the + + align:start position:0% +one is equal to one and that's the + + + align:start position:0% +one is equal to one and that's the +definition of being relatively prime so + + align:start position:0% +definition of being relatively prime so + + + align:start position:0% +definition of being relatively prime so +this is a good + + align:start position:0% +this is a good + + + align:start position:0% +this is a good +number H the gcd of 12 and two well both + + align:start position:0% +number H the gcd of 12 and two well both + + + align:start position:0% +number H the gcd of 12 and two well both +are divisible by two and so they're not + + align:start position:0% +are divisible by two and so they're not + + + align:start position:0% +are divisible by two and so they're not +relatively prime because the gcd is at + + align:start position:0% +relatively prime because the gcd is at + + + align:start position:0% +relatively prime because the gcd is at +least two in this case equal to two + + align:start position:0% +least two in this case equal to two + + + align:start position:0% +least two in this case equal to two +three also divides 12 four divides 12 + + align:start position:0% +three also divides 12 four divides 12 + + + align:start position:0% +three also divides 12 four divides 12 +five is relatively prime with respect to + + align:start position:0% +five is relatively prime with respect to + + + align:start position:0% +five is relatively prime with respect to +12 six actually is is dividing 12 as + + align:start position:0% +12 six actually is is dividing 12 as + + + align:start position:0% +12 six actually is is dividing 12 as +well seven is relatively + + align:start position:0% +well seven is relatively + + + align:start position:0% +well seven is relatively +prime and 11 over here as well and all + + align:start position:0% +prime and 11 over here as well and all + + + align:start position:0% +prime and 11 over here as well and all +the others have a greatest common + + align:start position:0% +the others have a greatest common + + + align:start position:0% +the others have a greatest common +divisor that is larger than one so here + + align:start position:0% +divisor that is larger than one so here + + + align:start position:0% +divisor that is larger than one so here +we see that the ELO function in + + align:start position:0% +we see that the ELO function in + + + align:start position:0% +we see that the ELO function in +evaluated in 12 is equal to four there + + align:start position:0% +evaluated in 12 is equal to four there + + + align:start position:0% +evaluated in 12 is equal to four there +are one two three four integers that are + + align:start position:0% +are one two three four integers that are + + + align:start position:0% +are one two three four integers that are +relatively + + align:start position:0% +relatively + + + align:start position:0% +relatively +prime okay so let's have a different one + + align:start position:0% +prime okay so let's have a different one + + + align:start position:0% +prime okay so let's have a different one +say n equals 15 it's a little bit + + align:start position:0% +say n equals 15 it's a little bit + + + align:start position:0% +say n equals 15 it's a little bit +different because here you may think + + align:start position:0% +different because here you may think + + + align:start position:0% +different because here you may think +this is kind of coincidental that 1 5 7 + + align:start position:0% +this is kind of coincidental that 1 5 7 + + + align:start position:0% +this is kind of coincidental that 1 5 7 +and 11 are actually also primes but for + + align:start position:0% +and 11 are actually also primes but for + + + align:start position:0% +and 11 are actually also primes but for +15 it looks a little bit + + align:start position:0% + + + + align:start position:0% + +different so let's write out all + + align:start position:0% +different so let's write out all + + + align:start position:0% +different so let's write out all +the + + align:start position:0% +the + + + align:start position:0% +the +numbers um again let's have a look well + + align:start position:0% +numbers um again let's have a look well + + + align:start position:0% +numbers um again let's have a look well +one is greatest comma divisor equal to + + align:start position:0% +one is greatest comma divisor equal to + + + align:start position:0% +one is greatest comma divisor equal to +one to with respect to 15 uh two well is + + align:start position:0% +one to with respect to 15 uh two well is + + + align:start position:0% +one to with respect to 15 uh two well is +also relatively prime with respect to 15 + + align:start position:0% +also relatively prime with respect to 15 + + + align:start position:0% +also relatively prime with respect to 15 +three is dividing 15 four yeah four and + + align:start position:0% +three is dividing 15 four yeah four and + + + align:start position:0% +three is dividing 15 four yeah four and +15 have greatest common divisor equal to + + align:start position:0% +15 have greatest common divisor equal to + + + align:start position:0% +15 have greatest common divisor equal to +one so that's relatively prime um five + + align:start position:0% +one so that's relatively prime um five + + + align:start position:0% +one so that's relatively prime um five +is not uh six is not seven is relatively + + align:start position:0% +is not uh six is not seven is relatively + + + align:start position:0% +is not uh six is not seven is relatively +prime eight again this is only divisible + + align:start position:0% +prime eight again this is only divisible + + + align:start position:0% +prime eight again this is only divisible +by Power of Two And this has no power of + + align:start position:0% +by Power of Two And this has no power of + + + align:start position:0% +by Power of Two And this has no power of +two in it uh 9 10 uh are this one is + + align:start position:0% +two in it uh 9 10 uh are this one is + + + align:start position:0% +two in it uh 9 10 uh are this one is +divisible by five divisible by three 11 + + align:start position:0% +divisible by five divisible by three 11 + + + align:start position:0% +divisible by five divisible by three 11 +is again relatively prime and then we + + align:start position:0% +is again relatively prime and then we + + + align:start position:0% +is again relatively prime and then we +have 13 is relatively prime as well and + + align:start position:0% +have 13 is relatively prime as well and + + + align:start position:0% +have 13 is relatively prime as well and +14 as well because this is 2 * 7 and + + align:start position:0% +14 as well because this is 2 * 7 and + + + align:start position:0% +14 as well because this is 2 * 7 and +this is 3 * 5 so how many do we see now + + align:start position:0% +this is 3 * 5 so how many do we see now + + + align:start position:0% +this is 3 * 5 so how many do we see now +1 2 3 four five six seven eight + + align:start position:0% + + + + align:start position:0% + +so the O toci function evaluated in 15 + + align:start position:0% +so the O toci function evaluated in 15 + + + align:start position:0% +so the O toci function evaluated in 15 +is actually equal to + + align:start position:0% +is actually equal to + + + align:start position:0% +is actually equal to +8 now it turns out that uh this uh + + align:start position:0% +8 now it turns out that uh this uh + + + align:start position:0% +8 now it turns out that uh this uh +function has really nice properties and + + align:start position:0% +function has really nice properties and + + + align:start position:0% +function has really nice properties and +you can uh easily calculate if you know + + align:start position:0% +you can uh easily calculate if you know + + + align:start position:0% +you can uh easily calculate if you know +its uh if you know the decomposition of + + align:start position:0% +its uh if you know the decomposition of + + + align:start position:0% +its uh if you know the decomposition of +n into its primes and powers of primes + + align:start position:0% +n into its primes and powers of primes + + + align:start position:0% +n into its primes and powers of primes +you can easily compute uh this + + align:start position:0% +you can easily compute uh this + + + align:start position:0% +you can easily compute uh this +number F of + + align:start position:0% +number F of + + + align:start position:0% +number F of +n um + + align:start position:0% +n um + + + align:start position:0% +n um +now you will be able to find this in the + + align:start position:0% +now you will be able to find this in the + + + align:start position:0% +now you will be able to find this in the +book you should read it and also problem + + align:start position:0% +book you should read it and also problem + + + align:start position:0% +book you should read it and also problem +set talks about + + align:start position:0% +set talks about + + + align:start position:0% +set talks about +this but for now let's just uh uh talk + + align:start position:0% +this but for now let's just uh uh talk + + + align:start position:0% +this but for now let's just uh uh talk +about this as an abstract notion because + + align:start position:0% +about this as an abstract notion because + + + align:start position:0% +about this as an abstract notion because +that's all that we will use in this + + align:start position:0% +that's all that we will use in this + + + align:start position:0% +that's all that we will use in this +lecture but you will have a few + + align:start position:0% +lecture but you will have a few + + + align:start position:0% +lecture but you will have a few +exercises that talk about Computing this + + align:start position:0% +exercises that talk about Computing this + + + align:start position:0% +exercises that talk about Computing this +kind of + + align:start position:0% +kind of + + + align:start position:0% +kind of +stuff + + align:start position:0% +stuff + + + align:start position:0% +stuff +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +um let's talk about the ENT function uh + + align:start position:0% +um let's talk about the ENT function uh + + + align:start position:0% +um let's talk about the ENT function uh +and ear theorem so let me use + + align:start position:0% +and ear theorem so let me use + + + align:start position:0% +and ear theorem so let me use +uh this + + align:start position:0% + + + + align:start position:0% + +Blackboard now this is really an + + align:start position:0% +Blackboard now this is really an + + + align:start position:0% +Blackboard now this is really an +exciting + + align:start position:0% +exciting + + + align:start position:0% +exciting +theorem and it's a little bit hard to + + align:start position:0% +theorem and it's a little bit hard to + + + align:start position:0% +theorem and it's a little bit hard to +prove that's why we will need uh a + + align:start position:0% +prove that's why we will need uh a + + + align:start position:0% +prove that's why we will need uh a +little bit more time to do + + align:start position:0% +little bit more time to do + + + align:start position:0% +little bit more time to do +this um ear theorem says the following + + align:start position:0% +this um ear theorem says the following + + + align:start position:0% +this um ear theorem says the following +if if the + + align:start position:0% +if if the + + + align:start position:0% +if if the +gcd of N and + + align:start position:0% +gcd of N and + + + align:start position:0% +gcd of N and +K is equal to one uh + + align:start position:0% + + + + align:start position:0% + +then K to the + + align:start position:0% +then K to the + + + align:start position:0% +then K to the +power the ear to function evaluated in N + + align:start position:0% +power the ear to function evaluated in N + + + align:start position:0% +power the ear to function evaluated in N +is actually congruent to One + + align:start position:0% +is actually congruent to One + + + align:start position:0% +is actually congruent to One +modulo + + align:start position:0% +modulo + + + align:start position:0% +modulo +n so this is what we're going to prove + + align:start position:0% +n so this is what we're going to prove + + + align:start position:0% +n so this is what we're going to prove +here so why is this so + + align:start position:0% +here so why is this so + + + align:start position:0% +here so why is this so +interesting well we will talk about an + + align:start position:0% +interesting well we will talk about an + + + align:start position:0% +interesting well we will talk about an +application which is a direct + + align:start position:0% +application which is a direct + + + align:start position:0% +application which is a direct +consequence of this theorem which we + + align:start position:0% +consequence of this theorem which we + + + align:start position:0% +consequence of this theorem which we +call Fat's a little theorem and that in + + align:start position:0% +call Fat's a little theorem and that in + + + align:start position:0% +call Fat's a little theorem and that in +turn we will use to explain the RSA + + align:start position:0% +turn we will use to explain the RSA + + + align:start position:0% +turn we will use to explain the RSA +algorithm and show how decryption works + + align:start position:0% +algorithm and show how decryption works + + + align:start position:0% +algorithm and show how decryption works +and so on so how can we prove + + align:start position:0% + + + + align:start position:0% + +this um he will start with uh a first + + align:start position:0% +this um he will start with uh a first + + + align:start position:0% +this um he will start with uh a first +LMA + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% + + + + align:start position:0% + +um and then we're going to do a few uh + + align:start position:0% +um and then we're going to do a few uh + + + align:start position:0% +um and then we're going to do a few uh +uh tricks mathematical tricks you will + + align:start position:0% +uh tricks mathematical tricks you will + + + align:start position:0% +uh tricks mathematical tricks you will +see it so the first LMA is that um if I + + align:start position:0% +see it so the first LMA is that um if I + + + align:start position:0% +see it so the first LMA is that um if I +know that the gcd which is what we + + align:start position:0% +know that the gcd which is what we + + + align:start position:0% +know that the gcd which is what we +assuming the statement of the theorem if + + align:start position:0% +assuming the statement of the theorem if + + + align:start position:0% +assuming the statement of the theorem if +I know that the gcd of N and k equals 1 + + align:start position:0% + + + + align:start position:0% + +then I know that um a * K if a * K is + + align:start position:0% +then I know that um a * K if a * K is + + + align:start position:0% +then I know that um a * K if a * K is +congruent to B * + + align:start position:0% +congruent to B * + + + align:start position:0% +congruent to B * +k modul + + align:start position:0% +k modul + + + align:start position:0% +k modul +n then this applies that a is congruent + + align:start position:0% +n then this applies that a is congruent + + + align:start position:0% +n then this applies that a is congruent +to b modulo n well this seems to be kind + + align:start position:0% +to b modulo n well this seems to be kind + + + align:start position:0% +to b modulo n well this seems to be kind +of straightforward Lama I will only talk + + align:start position:0% +of straightforward Lama I will only talk + + + align:start position:0% +of straightforward Lama I will only talk +about it proof um so how do we do it + + align:start position:0% +about it proof um so how do we do it + + + align:start position:0% +about it proof um so how do we do it +well first of all I know that the G of N + + align:start position:0% +well first of all I know that the G of N + + + align:start position:0% +well first of all I know that the G of N +and k equals 1 so that means that um I + + align:start position:0% +and k equals 1 so that means that um I + + + align:start position:0% +and k equals 1 so that means that um I +can create a multiplicative inverse + + align:start position:0% +can create a multiplicative inverse + + + align:start position:0% +can create a multiplicative inverse +because I know that there is such a + + align:start position:0% +because I know that there is such a + + + align:start position:0% +because I know that there is such a +linear + + align:start position:0% +linear + + + align:start position:0% +linear +combination that uh that will end up to + + align:start position:0% +combination that uh that will end up to + + + align:start position:0% +combination that uh that will end up to +one + + align:start position:0% +one + + + align:start position:0% +one +so I have the multiplicative inverse I + + align:start position:0% +so I have the multiplicative inverse I + + + align:start position:0% +so I have the multiplicative inverse I +multiply both sides with this and then I + + align:start position:0% +multiply both sides with this and then I + + + align:start position:0% +multiply both sides with this and then I +will end up to a is congruent to b modul + + align:start position:0% +will end up to a is congruent to b modul + + + align:start position:0% +will end up to a is congruent to b modul +n and actually you can use some of the + + align:start position:0% +n and actually you can use some of the + + + align:start position:0% +n and actually you can use some of the +facts on your sheet to uh to prove this + + align:start position:0% +facts on your sheet to uh to prove this + + + align:start position:0% +facts on your sheet to uh to prove this +and uh in the problem set you probably + + align:start position:0% +and uh in the problem set you probably + + + align:start position:0% +and uh in the problem set you probably +have seen that there are a number of uh + + align:start position:0% +have seen that there are a number of uh + + + align:start position:0% +have seen that there are a number of uh +problems related to this and uh you will + + align:start position:0% +problems related to this and uh you will + + + align:start position:0% +problems related to this and uh you will +also so you will recognize this and + + align:start position:0% +also so you will recognize this and + + + align:start position:0% +also so you will recognize this and +prove a few of these things + + align:start position:0% +prove a few of these things + + + align:start position:0% +prove a few of these things +yourself okay + + align:start position:0% +yourself okay + + + align:start position:0% +yourself okay +so + + align:start position:0% +so + + + align:start position:0% +so +um so this is uh so let me see + + align:start position:0% + + + + align:start position:0% + +so let me see what we have done here + + align:start position:0% +so let me see what we have done here + + + align:start position:0% +so let me see what we have done here +um actually I noticed that I've missed + + align:start position:0% +um actually I noticed that I've missed + + + align:start position:0% +um actually I noticed that I've missed +one statement that I would like to + + align:start position:0% +one statement that I would like to + + + align:start position:0% +one statement that I would like to +explicitly mention I mean I've used it a + + align:start position:0% +explicitly mention I mean I've used it a + + + align:start position:0% +explicitly mention I mean I've used it a +few + + align:start position:0% +few + + + align:start position:0% +few +times let me do that first which is that + + align:start position:0% +times let me do that first which is that + + + align:start position:0% +times let me do that first which is that +um we know that uh if the + + align:start position:0% +um we know that uh if the + + + align:start position:0% +um we know that uh if the +gcd of N and k equals + + align:start position:0% +gcd of N and k equals + + + align:start position:0% +gcd of N and k equals +one uh then + + align:start position:0% +one uh then + + + align:start position:0% +one uh then +if and this is if and only if the case + + align:start position:0% +if and this is if and only if the case + + + align:start position:0% +if and this is if and only if the case +if K has a multiplicative inverse I + + align:start position:0% +if K has a multiplicative inverse I + + + align:start position:0% +if K has a multiplicative inverse I +didn't I've not yet explicitly stated + + align:start position:0% + + + + align:start position:0% + +this and we can uh easily see this let + + align:start position:0% +this and we can uh easily see this let + + + align:start position:0% +this and we can uh easily see this let +me just give a quick + + align:start position:0% +me just give a quick + + + align:start position:0% +me just give a quick +proof to show how this + + align:start position:0% +proof to show how this + + + align:start position:0% +proof to show how this +works um well if the gcd is equal to one + + align:start position:0% + + + + align:start position:0% + +then we use the statement up + + align:start position:0% +then we use the statement up + + + align:start position:0% +then we use the statement up +there so this is uh if and only if there + + align:start position:0% +there so this is uh if and only if there + + + align:start position:0% +there so this is uh if and only if there +exists a linear combination so an S and + + align:start position:0% +exists a linear combination so an S and + + + align:start position:0% +exists a linear combination so an S and +a t such that n * s + K * T = + + align:start position:0% +a t such that n * s + K * T = + + + align:start position:0% +a t such that n * s + K * T = +1 well then I also know that there + + align:start position:0% +1 well then I also know that there + + + align:start position:0% +1 well then I also know that there +exists uh a t such that um actually the + + align:start position:0% +exists uh a t such that um actually the + + + align:start position:0% +exists uh a t such that um actually the +the difference uh between 1 and K * T is + + align:start position:0% +the difference uh between 1 and K * T is + + + align:start position:0% +the difference uh between 1 and K * T is +divisible by + + align:start position:0% +divisible by + + + align:start position:0% +divisible by +n so n divides the difference of K * T + + align:start position:0% +n so n divides the difference of K * T + + + align:start position:0% +n so n divides the difference of K * T +minus 1 so why is that well if I look at + + align:start position:0% +minus 1 so why is that well if I look at + + + align:start position:0% +minus 1 so why is that well if I look at +the difference between K * T and 1 that + + align:start position:0% +the difference between K * T and 1 that + + + align:start position:0% +the difference between K * T and 1 that +difference is n * s and n * s is + + align:start position:0% +difference is n * s and n * s is + + + align:start position:0% +difference is n * s and n * s is +divisible by n so now by the definition + + align:start position:0% +divisible by n so now by the definition + + + align:start position:0% +divisible by n so now by the definition +of + + align:start position:0% +of + + + align:start position:0% +of +congruence um I just apply the + + align:start position:0% +congruence um I just apply the + + + align:start position:0% +congruence um I just apply the +definition over here you have written it + + align:start position:0% +definition over here you have written it + + + align:start position:0% +definition over here you have written it +out here we can say that uh K * T is + + align:start position:0% +out here we can say that uh K * T is + + + align:start position:0% +out here we can say that uh K * T is +congruent to One + + align:start position:0% +congruent to One + + + align:start position:0% +congruent to One +modulo + + align:start position:0% +modulo + + + align:start position:0% +modulo +n and uh this is the definition of the + + align:start position:0% +n and uh this is the definition of the + + + align:start position:0% +n and uh this is the definition of the +multiplicative inverse so we have + + align:start position:0% +multiplicative inverse so we have + + + align:start position:0% +multiplicative inverse so we have +essentially shown that if the greatest + + align:start position:0% +essentially shown that if the greatest + + + align:start position:0% +essentially shown that if the greatest +common Defence between n and K is equal + + align:start position:0% +common Defence between n and K is equal + + + align:start position:0% +common Defence between n and K is equal +to one then it has a multiplicative + + align:start position:0% +to one then it has a multiplicative + + + align:start position:0% +to one then it has a multiplicative +inverse okay we have been using this uh + + align:start position:0% +inverse okay we have been using this uh + + + align:start position:0% +inverse okay we have been using this uh +property uh + + align:start position:0% +property uh + + + align:start position:0% +property uh +over + + align:start position:0% +over + + + align:start position:0% +over +here because we assume that the gra Comm + + align:start position:0% +here because we assume that the gra Comm + + + align:start position:0% +here because we assume that the gra Comm +divisor is equal to one so we now know + + align:start position:0% +divisor is equal to one so we now know + + + align:start position:0% +divisor is equal to one so we now know +that there exists a multiplicative + + align:start position:0% +that there exists a multiplicative + + + align:start position:0% +that there exists a multiplicative +inverse of K we use that one to + + align:start position:0% +inverse of K we use that one to + + + align:start position:0% +inverse of K we use that one to +multiply uh away essentially the K out + + align:start position:0% +multiply uh away essentially the K out + + + align:start position:0% +multiply uh away essentially the K out +of this equation and get a is congruent + + align:start position:0% +of this equation and get a is congruent + + + align:start position:0% +of this equation and get a is congruent +to b modul + + align:start position:0% +to b modul + + + align:start position:0% +to b modul +n also notice that we use that property + + align:start position:0% +n also notice that we use that property + + + align:start position:0% +n also notice that we use that property +over + + align:start position:0% +over + + + align:start position:0% +over +here um we said um that we uh + + align:start position:0% +here um we said um that we uh + + + align:start position:0% +here um we said um that we uh +wanted to + + align:start position:0% +wanted to + + + align:start position:0% +wanted to +compute uh what was it again uh oh over + + align:start position:0% +compute uh what was it again uh oh over + + + align:start position:0% +compute uh what was it again uh oh over +here we started off with the gcd of M + + align:start position:0% +here we started off with the gcd of M + + + align:start position:0% +here we started off with the gcd of M +and P to be equal to one and I know p + + align:start position:0% +and P to be equal to one and I know p + + + align:start position:0% +and P to be equal to one and I know p +and now I can compute the multiplicative + + align:start position:0% +and now I can compute the multiplicative + + + align:start position:0% +and now I can compute the multiplicative +inverse of M and I should have said why + + align:start position:0% +inverse of M and I should have said why + + + align:start position:0% +inverse of M and I should have said why +it exists and it exists because of that + + align:start position:0% +it exists and it exists because of that + + + align:start position:0% +it exists and it exists because of that +uh LMA that that I just mentioned up + + align:start position:0% +uh LMA that that I just mentioned up + + + align:start position:0% +uh LMA that that I just mentioned up +here okay so now let's go back to ear's + + align:start position:0% +here okay so now let's go back to ear's + + + align:start position:0% +here okay so now let's go back to ear's +theorem um + + align:start position:0% +theorem um + + + align:start position:0% +theorem um +this first LMA we are going to use to + + align:start position:0% +this first LMA we are going to use to + + + align:start position:0% +this first LMA we are going to use to +prove a second LMA and that second LMA + + align:start position:0% +prove a second LMA and that second LMA + + + align:start position:0% +prove a second LMA and that second LMA +we can finally use to prove the + + align:start position:0% + + + + align:start position:0% + +theorem all + + align:start position:0% +theorem all + + + align:start position:0% +theorem all +right so this LMA I will put on a + + align:start position:0% +right so this LMA I will put on a + + + align:start position:0% +right so this LMA I will put on a +separate + + align:start position:0% +separate + + + align:start position:0% +separate +board um because it contains quite a + + align:start position:0% +board um because it contains quite a + + + align:start position:0% +board um because it contains quite a +number of steps to + + align:start position:0% + + + + align:start position:0% + +prove so the LMA states that um if we + + align:start position:0% +prove so the LMA states that um if we + + + align:start position:0% +prove so the LMA states that um if we +suppose + + align:start position:0% +suppose + + + align:start position:0% +suppose +that um the + + align:start position:0% +that um the + + + align:start position:0% +that um the +gcd of N and k equals 1 so it's the same + + align:start position:0% +gcd of N and k equals 1 so it's the same + + + align:start position:0% +gcd of N and k equals 1 so it's the same +assumption as + + align:start position:0% +assumption as + + + align:start position:0% +assumption as +before um if we let uh + + align:start position:0% +before um if we let uh + + + align:start position:0% +before um if we let uh +K1 all the way up to KR to be those + + align:start position:0% +K1 all the way up to KR to be those + + + align:start position:0% +K1 all the way up to KR to be those +integers in the range one 2 3 and so on + + align:start position:0% +integers in the range one 2 3 and so on + + + align:start position:0% +integers in the range one 2 3 and so on +to n minus one um that are relatively + + align:start position:0% +to n minus one um that are relatively + + + align:start position:0% +to n minus one um that are relatively +prime so these + + align:start position:0% +prime so these + + + align:start position:0% +prime so these +denote the integers relatively prime to + + align:start position:0% +denote the integers relatively prime to + + + align:start position:0% +denote the integers relatively prime to +uh + + align:start position:0% + + + + align:start position:0% + +n then we can uh prove a very + + align:start position:0% +n then we can uh prove a very + + + align:start position:0% +n then we can uh prove a very +interesting + + align:start position:0% +interesting + + + align:start position:0% +interesting +property now notice by the way that uh R + + align:start position:0% +property now notice by the way that uh R + + + align:start position:0% +property now notice by the way that uh R +in here is equal to the value of of the + + align:start position:0% +in here is equal to the value of of the + + + align:start position:0% +in here is equal to the value of of the +ear stent function evaluated in N + + align:start position:0% +ear stent function evaluated in N + + + align:start position:0% +ear stent function evaluated in N +because this counts the total number of + + align:start position:0% +because this counts the total number of + + + align:start position:0% +because this counts the total number of +uh of of numbers that are relatively + + align:start position:0% +uh of of numbers that are relatively + + + align:start position:0% +uh of of numbers that are relatively +primes um Prime with respect to + + align:start position:0% +primes um Prime with respect to + + + align:start position:0% +primes um Prime with respect to +n so now we can prove something really + + align:start position:0% +n so now we can prove something really + + + align:start position:0% +n so now we can prove something really +spectacular um we can show that the set + + align:start position:0% +spectacular um we can show that the set + + + align:start position:0% +spectacular um we can show that the set +that contains all these remainders the + + align:start position:0% +that contains all these remainders the + + + align:start position:0% +that contains all these remainders the +remainder of K1 * + + align:start position:0% +remainder of K1 * + + + align:start position:0% +remainder of K1 * +K after dividing out as many multiples + + align:start position:0% +K after dividing out as many multiples + + + align:start position:0% +K after dividing out as many multiples +of n is + + align:start position:0% +of n is + + + align:start position:0% +of n is +possible all the way to the remainder of + + align:start position:0% +possible all the way to the remainder of + + + align:start position:0% +possible all the way to the remainder of +KR times K after dividing out as many + + align:start position:0% +KR times K after dividing out as many + + + align:start position:0% +KR times K after dividing out as many +multiples of n as + + align:start position:0% +multiples of n as + + + align:start position:0% +multiples of n as +possible this set is actually equal to + + align:start position:0% +possible this set is actually equal to + + + align:start position:0% +possible this set is actually equal to +the set K1 up to + + align:start position:0% +the set K1 up to + + + align:start position:0% +the set K1 up to +KR so this is what we're going to prove + + align:start position:0% +KR so this is what we're going to prove + + + align:start position:0% +KR so this is what we're going to prove +and we'll do it in two steps uh we first + + align:start position:0% +and we'll do it in two steps uh we first + + + align:start position:0% +and we'll do it in two steps uh we first +show that this set + + align:start position:0% +show that this set + + + align:start position:0% +show that this set +uh has exactly R numbers so the + + align:start position:0% +uh has exactly R numbers so the + + + align:start position:0% +uh has exactly R numbers so the +cardinality of that set is equal to R so + + align:start position:0% +cardinality of that set is equal to R so + + + align:start position:0% +cardinality of that set is equal to R so +that will be our first step in the + + align:start position:0% +that will be our first step in the + + + align:start position:0% +that will be our first step in the +proof and over here we will show that + + align:start position:0% +proof and over here we will show that + + + align:start position:0% +proof and over here we will show that +every remainder is actually a relatively + + align:start position:0% +every remainder is actually a relatively + + + align:start position:0% +every remainder is actually a relatively +prime to n so it must be part of this + + align:start position:0% +prime to n so it must be part of this + + + align:start position:0% +prime to n so it must be part of this +set so we will show that this is a + + align:start position:0% +set so we will show that this is a + + + align:start position:0% +set so we will show that this is a +subset of this set in the second part of + + align:start position:0% +subset of this set in the second part of + + + align:start position:0% +subset of this set in the second part of +the proof and combining those two we are + + align:start position:0% +the proof and combining those two we are + + + align:start position:0% +the proof and combining those two we are +able to prove equality why is that well + + align:start position:0% +able to prove equality why is that well + + + align:start position:0% +able to prove equality why is that well +I I have R distinct elements in this set + + align:start position:0% +I I have R distinct elements in this set + + + align:start position:0% +I I have R distinct elements in this set +I have R distinct elements in this set + + align:start position:0% +I have R distinct elements in this set + + + align:start position:0% +I have R distinct elements in this set +this one is a subset of this so that can + + align:start position:0% +this one is a subset of this so that can + + + align:start position:0% +this one is a subset of this so that can +only happen if they are + + align:start position:0% +only happen if they are + + + align:start position:0% +only happen if they are +equal so this is the uh the method for + + align:start position:0% +equal so this is the uh the method for + + + align:start position:0% +equal so this is the uh the method for +uh the + + align:start position:0% + + + + align:start position:0% + +proof oh I should + + align:start position:0% + + + + align:start position:0% + +um so we will start with the first + + align:start position:0% + + + + align:start position:0% + +part and the way to do that is to uh see + + align:start position:0% +part and the way to do that is to uh see + + + align:start position:0% +part and the way to do that is to uh see +whether it is possible that whether it's + + align:start position:0% +whether it is possible that whether it's + + + align:start position:0% +whether it is possible that whether it's +possible that if that any of those two + + align:start position:0% +possible that if that any of those two + + + align:start position:0% +possible that if that any of those two +REM any two remainders in that set can + + align:start position:0% +REM any two remainders in that set can + + + align:start position:0% +REM any two remainders in that set can +they be equal to one another we will + + align:start position:0% +they be equal to one another we will + + + align:start position:0% +they be equal to one another we will +show that that's not possible so if it's + + align:start position:0% +show that that's not possible so if it's + + + align:start position:0% +show that that's not possible so if it's +not possible then all these remainders + + align:start position:0% +not possible then all these remainders + + + align:start position:0% +not possible then all these remainders +must be different and we have exactly R + + align:start position:0% +must be different and we have exactly R + + + align:start position:0% +must be different and we have exactly R +of those + + align:start position:0% +of those + + + align:start position:0% +of those +so let's do this so the proof for uh + + align:start position:0% +so let's do this so the proof for uh + + + align:start position:0% +so let's do this so the proof for uh +one is as follows let's assume that we + + align:start position:0% +one is as follows let's assume that we + + + align:start position:0% +one is as follows let's assume that we +have two remainders say k i * + + align:start position:0% +have two remainders say k i * + + + align:start position:0% +have two remainders say k i * +k + + align:start position:0% +k + + + align:start position:0% +k +um and uh a + + align:start position:0% +um and uh a + + + align:start position:0% +um and uh a +remainder k j * K after dividing out as + + align:start position:0% +remainder k j * K after dividing out as + + + align:start position:0% +remainder k j * K after dividing out as +many multiples of n supposed that they + + align:start position:0% +many multiples of n supposed that they + + + align:start position:0% +many multiples of n supposed that they +are equal to one another you're going to + + align:start position:0% +are equal to one another you're going to + + + align:start position:0% +are equal to one another you're going to +show that this can only happen if Ki is + + align:start position:0% +show that this can only happen if Ki is + + + align:start position:0% +show that this can only happen if Ki is +equal to + + align:start position:0% +equal to + + + align:start position:0% +equal to +KJ and if you uh can see that well then + + align:start position:0% +KJ and if you uh can see that well then + + + align:start position:0% +KJ and if you uh can see that well then +we know that all these different + + align:start position:0% +we know that all these different + + + align:start position:0% +we know that all these different +remainders are actually different from + + align:start position:0% +remainders are actually different from + + + align:start position:0% +remainders are actually different from +one another and if they're all different + + align:start position:0% +one another and if they're all different + + + align:start position:0% +one another and if they're all different +from one another then we must have + + align:start position:0% +from one another then we must have + + + align:start position:0% +from one another then we must have +exactly R because we have K1 up to KR in + + align:start position:0% +exactly R because we have K1 up to KR in + + + align:start position:0% +exactly R because we have K1 up to KR in +here okay let's uh let's see where we + + align:start position:0% +here okay let's uh let's see where we + + + align:start position:0% +here okay let's uh let's see where we +can do this um + + align:start position:0% +can do this um + + + align:start position:0% +can do this um +well if we know that these two + + align:start position:0% +well if we know that these two + + + align:start position:0% +well if we know that these two +remainders are equal to one another we + + align:start position:0% +remainders are equal to one another we + + + align:start position:0% +remainders are equal to one another we +can look at them uh with respect to uh + + align:start position:0% +can look at them uh with respect to uh + + + align:start position:0% +can look at them uh with respect to uh +these definitions over here and we can + + align:start position:0% +these definitions over here and we can + + + align:start position:0% +these definitions over here and we can +uh show that k i * K is actually + + align:start position:0% +uh show that k i * K is actually + + + align:start position:0% +uh show that k i * K is actually +congruent to K J * k modul n so why is + + align:start position:0% +congruent to K J * k modul n so why is + + + align:start position:0% +congruent to K J * k modul n so why is +this well these two remainders are the + + align:start position:0% +this well these two remainders are the + + + align:start position:0% +this well these two remainders are the +same and Ki * K is equal to this + + align:start position:0% +same and Ki * K is equal to this + + + align:start position:0% +same and Ki * K is equal to this +remainder plus a multiple of n this KJ * + + align:start position:0% +remainder plus a multiple of n this KJ * + + + align:start position:0% +remainder plus a multiple of n this KJ * +K is equal to this remainder plus a + + align:start position:0% +K is equal to this remainder plus a + + + align:start position:0% +K is equal to this remainder plus a +multiple of n + + align:start position:0% +multiple of n + + + align:start position:0% +multiple of n +so the difference between those two are + + align:start position:0% +so the difference between those two are + + + align:start position:0% +so the difference between those two are +also is is also a multiple of N and + + align:start position:0% +also is is also a multiple of N and + + + align:start position:0% +also is is also a multiple of N and +that's the definition of + + align:start position:0% + + + + align:start position:0% + +congruence so now uh we can uh use our + + align:start position:0% +congruence so now uh we can uh use our + + + align:start position:0% +congruence so now uh we can uh use our +uh first LMA that is which is stated + + align:start position:0% +uh first LMA that is which is stated + + + align:start position:0% +uh first LMA that is which is stated +over + + align:start position:0% +over + + + align:start position:0% +over +here we know that we assumed in ear + + align:start position:0% +here we know that we assumed in ear + + + align:start position:0% +here we know that we assumed in ear +theorem that the gcd of N and K is equal + + align:start position:0% +theorem that the gcd of N and K is equal + + + align:start position:0% +theorem that the gcd of N and K is equal +to + + align:start position:0% +to + + + align:start position:0% +to +one um if a * K is congruent to B * k + + align:start position:0% +one um if a * K is congruent to B * k + + + align:start position:0% +one um if a * K is congruent to B * k +modul n then we know that a is congruent + + align:start position:0% +modul n then we know that a is congruent + + + align:start position:0% +modul n then we know that a is congruent +to b modulo n so let's apply it over + + align:start position:0% +to b modulo n so let's apply it over + + + align:start position:0% +to b modulo n so let's apply it over +here and take for a Ki and for B we can + + align:start position:0% +here and take for a Ki and for B we can + + + align:start position:0% +here and take for a Ki and for B we can +take + + align:start position:0% +take + + + align:start position:0% +take +KJ so now we see that key Ki is + + align:start position:0% +KJ so now we see that key Ki is + + + align:start position:0% +KJ so now we see that key Ki is +congruent to k j modulo + + align:start position:0% +congruent to k j modulo + + + align:start position:0% +congruent to k j modulo +n and from this we will + + align:start position:0% +n and from this we will + + + align:start position:0% +n and from this we will +conclude and that takes an extra + + align:start position:0% +conclude and that takes an extra + + + align:start position:0% +conclude and that takes an extra +step that Ki is actually equal to KJ so + + align:start position:0% +step that Ki is actually equal to KJ so + + + align:start position:0% +step that Ki is actually equal to KJ so +how can we do this well we know that uh + + align:start position:0% +how can we do this well we know that uh + + + align:start position:0% +how can we do this well we know that uh +Ki and KJ are both in the range from one + + align:start position:0% +Ki and KJ are both in the range from one + + + align:start position:0% +Ki and KJ are both in the range from one +all the way up to n minus + + align:start position:0% +all the way up to n minus + + + align:start position:0% +all the way up to n minus +one + + align:start position:0% +one + + + align:start position:0% +one +so if I look at the difference between + + align:start position:0% +so if I look at the difference between + + + align:start position:0% +so if I look at the difference between +those two so by definition of congruence + + align:start position:0% +those two so by definition of congruence + + + align:start position:0% +those two so by definition of congruence +I know um that n + + align:start position:0% +I know um that n + + + align:start position:0% +I know um that n +divides k i minus + + align:start position:0% +divides k i minus + + + align:start position:0% +divides k i minus +KJ I know that this one is in the range + + align:start position:0% +KJ I know that this one is in the range + + + align:start position:0% +KJ I know that this one is in the range +from uh 0 up to n minus one this one is + + align:start position:0% +from uh 0 up to n minus one this one is + + + align:start position:0% +from uh 0 up to n minus one this one is +in the range of 0 up to n minus one the + + align:start position:0% +in the range of 0 up to n minus one the + + + align:start position:0% +in the range of 0 up to n minus one the +only way + + align:start position:0% +only way + + + align:start position:0% +only way +how the how a difference of two numbers + + align:start position:0% +how the how a difference of two numbers + + + align:start position:0% +how the how a difference of two numbers +in this range can be divisible by n if + + align:start position:0% +in this range can be divisible by n if + + + align:start position:0% +in this range can be divisible by n if +this thing is equal to + + align:start position:0% +this thing is equal to + + + align:start position:0% +this thing is equal to +zero and that means that Ki equals KJ so + + align:start position:0% +zero and that means that Ki equals KJ so + + + align:start position:0% +zero and that means that Ki equals KJ so +now we are done with the first part + + align:start position:0% +now we are done with the first part + + + align:start position:0% +now we are done with the first part +because we have shown that if I take any + + align:start position:0% +because we have shown that if I take any + + + align:start position:0% +because we have shown that if I take any +two remainders over here it must be that + + align:start position:0% +two remainders over here it must be that + + + align:start position:0% +two remainders over here it must be that +they can only be equal to one another if + + align:start position:0% +they can only be equal to one another if + + + align:start position:0% +they can only be equal to one another if +actually the Ki is equal to the KJ so we + + align:start position:0% +actually the Ki is equal to the KJ so we + + + align:start position:0% +actually the Ki is equal to the KJ so we +actually we're looking at the same + + align:start position:0% +actually we're looking at the same + + + align:start position:0% +actually we're looking at the same +remainder so the remainders in this set + + align:start position:0% +remainder so the remainders in this set + + + align:start position:0% +remainder so the remainders in this set +are all different and there are exactly + + align:start position:0% +are all different and there are exactly + + + align:start position:0% +are all different and there are exactly +R of those so now we go to the second + + align:start position:0% +R of those so now we go to the second + + + align:start position:0% +R of those so now we go to the second +part of the + + align:start position:0% +part of the + + + align:start position:0% +part of the +proof + + align:start position:0% + + + + align:start position:0% + +uh and + + align:start position:0% + + + + align:start position:0% + +um and notice that we are so far we've + + align:start position:0% +um and notice that we are so far we've + + + align:start position:0% +um and notice that we are so far we've +only been proving this second LMA and we + + align:start position:0% +only been proving this second LMA and we + + + align:start position:0% +only been proving this second LMA and we +still need to go to ear theorem as as + + align:start position:0% +still need to go to ear theorem as as + + + align:start position:0% +still need to go to ear theorem as as +well so it still takes a few + + align:start position:0% +well so it still takes a few + + + align:start position:0% +well so it still takes a few +steps + + align:start position:0% +steps + + + align:start position:0% +steps +um so how do we do the second + + align:start position:0% +um so how do we do the second + + + align:start position:0% +um so how do we do the second +part well we saw in last lecture that uh + + align:start position:0% +part well we saw in last lecture that uh + + + align:start position:0% +part well we saw in last lecture that uh +we were explaining uh uh ukids uh + + align:start position:0% +we were explaining uh uh ukids uh + + + align:start position:0% +we were explaining uh uh ukids uh +algorithm and we used essentially this + + align:start position:0% +algorithm and we used essentially this + + + align:start position:0% +algorithm and we used essentially this +property we said that the greatest + + align:start position:0% +property we said that the greatest + + + align:start position:0% +property we said that the greatest +comice between n and the remainder of uh + + align:start position:0% +comice between n and the remainder of uh + + + align:start position:0% +comice between n and the remainder of uh +say k i * K and N + + align:start position:0% + + + + align:start position:0% + +is actually equal to the greatest common + + align:start position:0% +is actually equal to the greatest common + + + align:start position:0% +is actually equal to the greatest common +divisor of N and k i * + + align:start position:0% + + + + align:start position:0% + +K so why is this again well the + + align:start position:0% +K so why is this again well the + + + align:start position:0% +K so why is this again well the +remainder is actually um equal to k i * + + align:start position:0% +remainder is actually um equal to k i * + + + align:start position:0% +remainder is actually um equal to k i * +K minus a multiple of n right so the + + align:start position:0% +K minus a multiple of n right so the + + + align:start position:0% +K minus a multiple of n right so the +greatest common divisor is therefore + + align:start position:0% +greatest common divisor is therefore + + + align:start position:0% +greatest common divisor is therefore +between n and this is the same as the + + align:start position:0% +between n and this is the same as the + + + align:start position:0% +between n and this is the same as the +greatest common devisor between n and K + + align:start position:0% +greatest common devisor between n and K + + + align:start position:0% +greatest common devisor between n and K +k i * K so you should have a look at + + align:start position:0% +k i * K so you should have a look at + + + align:start position:0% +k i * K so you should have a look at +last lecture and uh now we are pretty + + align:start position:0% +last lecture and uh now we are pretty + + + align:start position:0% +last lecture and uh now we are pretty +much done why is this because we have + + align:start position:0% +much done why is this because we have + + + align:start position:0% +much done why is this because we have +assumed that the greatest common divisor + + align:start position:0% +assumed that the greatest common divisor + + + align:start position:0% +assumed that the greatest common divisor +between n and K is equal to one and k i + + align:start position:0% +between n and K is equal to one and k i + + + align:start position:0% +between n and K is equal to one and k i +in the statement of the LMA is + + align:start position:0% +in the statement of the LMA is + + + align:start position:0% +in the statement of the LMA is +relatively prime to n and that means + + align:start position:0% +relatively prime to n and that means + + + align:start position:0% +relatively prime to n and that means +according to the definition over there + + align:start position:0% +according to the definition over there + + + align:start position:0% +according to the definition over there +that the greatest common devisor between + + align:start position:0% +that the greatest common devisor between + + + align:start position:0% +that the greatest common devisor between +k i and N is also equal to one so we + + align:start position:0% +k i and N is also equal to one so we + + + align:start position:0% +k i and N is also equal to one so we +know + + align:start position:0% +know + + + align:start position:0% +know +that + + align:start position:0% +that + + + align:start position:0% +that +both + + align:start position:0% + + + + align:start position:0% + +these greatest common devisers are equal + + align:start position:0% +these greatest common devisers are equal + + + align:start position:0% +these greatest common devisers are equal +to + + align:start position:0% +to + + + align:start position:0% +to +one so that means that there is no + + align:start position:0% +one so that means that there is no + + + align:start position:0% +one so that means that there is no +common divisor between n and and this + + align:start position:0% +common divisor between n and and this + + + align:start position:0% +common divisor between n and and this +except for one of + + align:start position:0% +except for one of + + + align:start position:0% +except for one of +course so what does this say well this + + align:start position:0% +course so what does this say well this + + + align:start position:0% +course so what does this say well this +means that this remainder according to + + align:start position:0% +means that this remainder according to + + + align:start position:0% +means that this remainder according to +our definition is relatively prime to n + + align:start position:0% +our definition is relatively prime to n + + + align:start position:0% +our definition is relatively prime to n +because this greatest common devisor is + + align:start position:0% +because this greatest common devisor is + + + align:start position:0% +because this greatest common devisor is +equal to + + align:start position:0% +equal to + + + align:start position:0% +equal to +one so if it is a uh um integer + + align:start position:0% +one so if it is a uh um integer + + + align:start position:0% +one so if it is a uh um integer +relatively prime to n then it must be + + align:start position:0% +relatively prime to n then it must be + + + align:start position:0% +relatively prime to n then it must be +one of those k i KJS in this set that is + + align:start position:0% +one of those k i KJS in this set that is + + + align:start position:0% +one of those k i KJS in this set that is +stated in the + + align:start position:0% +stated in the + + + align:start position:0% +stated in the +LMA so this + + align:start position:0% +LMA so this + + + align:start position:0% +LMA so this +shows that it must be part of this set + + align:start position:0% +shows that it must be part of this set + + + align:start position:0% +shows that it must be part of this set +over here so we have Pro proven the the + + align:start position:0% +over here so we have Pro proven the the + + + align:start position:0% +over here so we have Pro proven the the +fact that the set of all the remainers + + align:start position:0% +fact that the set of all the remainers + + + align:start position:0% +fact that the set of all the remainers +is a subset of the set K1 up to KR so + + align:start position:0% +is a subset of the set K1 up to KR so + + + align:start position:0% +is a subset of the set K1 up to KR so +now we're done + + align:start position:0% + + + + align:start position:0% + +so now that we have shown this + + align:start position:0% +so now that we have shown this + + + align:start position:0% +so now that we have shown this +particular um uh + + align:start position:0% +particular um uh + + + align:start position:0% +particular um uh +LMA we can continue and um prove O's + + align:start position:0% +LMA we can continue and um prove O's + + + align:start position:0% +LMA we can continue and um prove O's +theorem and I will probably need to wipe + + align:start position:0% +theorem and I will probably need to wipe + + + align:start position:0% +theorem and I will probably need to wipe +out some of this uh + + align:start position:0% +out some of this uh + + + align:start position:0% +out some of this uh +yep so + + align:start position:0% + + + + align:start position:0% + +let's so let's use this LMA to prove + + align:start position:0% +let's so let's use this LMA to prove + + + align:start position:0% +let's so let's use this LMA to prove +this + + align:start position:0% +this + + + align:start position:0% +this +theorem so this is really a neat trick + + align:start position:0% + + + + align:start position:0% + +um so the proof of 's + + align:start position:0% + + + + align:start position:0% + +theorem is as follows we're going to + + align:start position:0% +theorem is as follows we're going to + + + align:start position:0% +theorem is as follows we're going to +take the product of all those k i over + + align:start position:0% +take the product of all those k i over + + + align:start position:0% +take the product of all those k i over +there and see whether we can find a nice + + align:start position:0% +there and see whether we can find a nice + + + align:start position:0% +there and see whether we can find a nice +relationship so we take K1 * K2 all the + + align:start position:0% +relationship so we take K1 * K2 all the + + + align:start position:0% +relationship so we take K1 * K2 all the +way times + + align:start position:0% +way times + + + align:start position:0% +way times +KR and we know because those two sets + + align:start position:0% +KR and we know because those two sets + + + align:start position:0% +KR and we know because those two sets +are actually the same + + align:start position:0% +are actually the same + + + align:start position:0% +are actually the same +that this is equal to the remainder the + + align:start position:0% +that this is equal to the remainder the + + + align:start position:0% +that this is equal to the remainder the +first remainder K * um K1 * + + align:start position:0% +first remainder K * um K1 * + + + align:start position:0% +first remainder K * um K1 * +k um after dividing out as many + + align:start position:0% +k um after dividing out as many + + + align:start position:0% +k um after dividing out as many +multiples of N and we go all the way up + + align:start position:0% +multiples of N and we go all the way up + + + align:start position:0% +multiples of N and we go all the way up +to the final one the remainder of + + align:start position:0% +to the final one the remainder of + + + align:start position:0% +to the final one the remainder of +KR time K dividing out as many multiples + + align:start position:0% +KR time K dividing out as many multiples + + + align:start position:0% +KR time K dividing out as many multiples +of n so + + align:start position:0% +of n so + + + align:start position:0% +of n so +now we can see that uh well we have + + align:start position:0% +now we can see that uh well we have + + + align:start position:0% +now we can see that uh well we have +already shown that that um each of those + + align:start position:0% +already shown that that um each of those + + + align:start position:0% +already shown that that um each of those +remainders right is congruent to in this + + align:start position:0% +remainders right is congruent to in this + + + align:start position:0% +remainders right is congruent to in this +case this one is congruent to K1 * k + + align:start position:0% +case this one is congruent to K1 * k + + + align:start position:0% +case this one is congruent to K1 * k +modulo n and this one is congruent to KR + + align:start position:0% +modulo n and this one is congruent to KR + + + align:start position:0% +modulo n and this one is congruent to KR +* k modulo n so let's write this out so + + align:start position:0% +* k modulo n so let's write this out so + + + align:start position:0% +* k modulo n so let's write this out so +it's K1 * K and then we have K2 * + + align:start position:0% +it's K1 * K and then we have K2 * + + + align:start position:0% +it's K1 * K and then we have K2 * +K and finally we have k r * + + align:start position:0% +K and finally we have k r * + + + align:start position:0% +K and finally we have k r * +k modulo + + align:start position:0% +k modulo + + + align:start position:0% +k modulo +n so let's uh regroup those + + align:start position:0% +n so let's uh regroup those + + + align:start position:0% +n so let's uh regroup those +we see K1 K2 all the way up to KR + + align:start position:0% + + + + align:start position:0% + +reappearing and we have a k here A K + + align:start position:0% +reappearing and we have a k here A K + + + align:start position:0% +reappearing and we have a k here A K +here and we have that R times so we have + + align:start position:0% +here and we have that R times so we have + + + align:start position:0% +here and we have that R times so we have +times K to the power + + align:start position:0% +times K to the power + + + align:start position:0% +times K to the power +r modulo + + align:start position:0% +r modulo + + + align:start position:0% +r modulo +n so now we are able to again use this + + align:start position:0% +n so now we are able to again use this + + + align:start position:0% +n so now we are able to again use this +particular LMA over here so what do we + + align:start position:0% +particular LMA over here so what do we + + + align:start position:0% +particular LMA over here so what do we +do well um we know that K1 is relatively + + align:start position:0% +do well um we know that K1 is relatively + + + align:start position:0% +do well um we know that K1 is relatively +prime to n and K2 is as well all the way + + align:start position:0% +prime to n and K2 is as well all the way + + + align:start position:0% +prime to n and K2 is as well all the way +up to KR so this whole product is also + + align:start position:0% +up to KR so this whole product is also + + + align:start position:0% +up to KR so this whole product is also +relatively prime with respect to n that + + align:start position:0% +relatively prime with respect to n that + + + align:start position:0% +relatively prime with respect to n that +means that the greatest common divisor + + align:start position:0% +means that the greatest common divisor + + + align:start position:0% +means that the greatest common divisor +of this whole product with n is equal to + + align:start position:0% +of this whole product with n is equal to + + + align:start position:0% +of this whole product with n is equal to +one so that means that I can divide out + + align:start position:0% +one so that means that I can divide out + + + align:start position:0% +one so that means that I can divide out +this whole + + align:start position:0% +this whole + + + align:start position:0% +this whole +product right we have uh so let's do do + + align:start position:0% +product right we have uh so let's do do + + + align:start position:0% +product right we have uh so let's do do +this we have say + + align:start position:0% +this we have say + + + align:start position:0% +this we have say +one times this product we take this for + + align:start position:0% +one times this product we take this for + + + align:start position:0% +one times this product we take this for +a and we take this for B and then we can + + align:start position:0% +a and we take this for B and then we can + + + align:start position:0% +a and we take this for B and then we can +divide this whole thing + + align:start position:0% +divide this whole thing + + + align:start position:0% +divide this whole thing +out uh according to this particular LMA + + align:start position:0% +out uh according to this particular LMA + + + align:start position:0% +out uh according to this particular LMA +by using the multiplicative inverse of + + align:start position:0% +by using the multiplicative inverse of + + + align:start position:0% +by using the multiplicative inverse of +that + + align:start position:0% +that + + + align:start position:0% +that +product so now we see that 1 is equal to + + align:start position:0% +product so now we see that 1 is equal to + + + align:start position:0% +product so now we see that 1 is equal to +K to ^ r modul n and remember in our + + align:start position:0% +K to ^ r modul n and remember in our + + + align:start position:0% +K to ^ r modul n and remember in our +theorem uh R over here in this LMA R is + + align:start position:0% +theorem uh R over here in this LMA R is + + + align:start position:0% +theorem uh R over here in this LMA R is +actually + + align:start position:0% +actually + + + align:start position:0% +actually +equal uh to + + align:start position:0% +equal uh to + + + align:start position:0% +equal uh to +the oion function in N so now this + + align:start position:0% +the oion function in N so now this + + + align:start position:0% +the oion function in N so now this +equation proves the whole + + align:start position:0% +equation proves the whole + + + align:start position:0% +equation proves the whole +theorem + + align:start position:0% +theorem + + + align:start position:0% +theorem +okay so um now I'm going to talk about + + align:start position:0% +okay so um now I'm going to talk about + + + align:start position:0% +okay so um now I'm going to talk about +RSA which is the last part here so maybe + + align:start position:0% +RSA which is the last part here so maybe + + + align:start position:0% +RSA which is the last part here so maybe +you all would like to have a little + + align:start position:0% +you all would like to have a little + + + align:start position:0% +you all would like to have a little +break of a couple of minutes just to + + align:start position:0% +break of a couple of minutes just to + + + align:start position:0% +break of a couple of minutes just to +relax a bit and then and shake hands + + align:start position:0% +relax a bit and then and shake hands + + + align:start position:0% +relax a bit and then and shake hands +with your neighbor + + align:start position:0% +with your neighbor + + + align:start position:0% +with your neighbor +and jump up in the air if you like to + + align:start position:0% +and jump up in the air if you like to + + + align:start position:0% +and jump up in the air if you like to +all right let's start with the RSA + + align:start position:0% +all right let's start with the RSA + + + align:start position:0% +all right let's start with the RSA +algorithm so we have done uh everything + + align:start position:0% +algorithm so we have done uh everything + + + align:start position:0% +algorithm so we have done uh everything +up to this point and we're actually uh + + align:start position:0% +up to this point and we're actually uh + + + align:start position:0% +up to this point and we're actually uh +we have done these two over here we + + align:start position:0% +we have done these two over here we + + + align:start position:0% +we have done these two over here we +still have to talk about F's little + + align:start position:0% +still have to talk about F's little + + + align:start position:0% +still have to talk about F's little +theorem but then we can go for RSA and + + align:start position:0% +theorem but then we can go for RSA and + + + align:start position:0% +theorem but then we can go for RSA and +that uses this consequence of uh Oilers + + align:start position:0% +that uses this consequence of uh Oilers + + + align:start position:0% +that uses this consequence of uh Oilers +theorem so + + align:start position:0% + + + + align:start position:0% + +fma's a little + + align:start position:0% + + + + align:start position:0% + +theorem is actually talking about what + + align:start position:0% +theorem is actually talking about what + + + align:start position:0% +theorem is actually talking about what +happens if N is a prime + + align:start position:0% + + + + align:start position:0% + +number it says well suppose p is a + + align:start position:0% + + + + align:start position:0% + +prime then uh and if you have + + align:start position:0% +prime then uh and if you have + + + align:start position:0% +prime then uh and if you have +K in the range 1 2 all the way up to P + + align:start position:0% +K in the range 1 2 all the way up to P + + + align:start position:0% +K in the range 1 2 all the way up to P +minus 1 + + align:start position:0% +minus 1 + + + align:start position:0% +minus 1 +then we can then we can conclude that K + + align:start position:0% +then we can then we can conclude that K + + + align:start position:0% +then we can then we can conclude that K +to ^ P minus one is congruent to One + + align:start position:0% +to ^ P minus one is congruent to One + + + align:start position:0% +to ^ P minus one is congruent to One +modulo + + align:start position:0% +modulo + + + align:start position:0% +modulo +n and we can directly prove this uh by + + align:start position:0% +n and we can directly prove this uh by + + + align:start position:0% +n and we can directly prove this uh by +using uh ear theorem so how do we do + + align:start position:0% +using uh ear theorem so how do we do + + + align:start position:0% +using uh ear theorem so how do we do +this well we know that P is + + align:start position:0% +this well we know that P is + + + align:start position:0% +this well we know that P is +prime so the numers + + align:start position:0% +prime so the numers + + + align:start position:0% +prime so the numers +one + + align:start position:0% +one + + + align:start position:0% +one +um one two all the way up to p - one are + + align:start position:0% +um one two all the way up to p - one are + + + align:start position:0% +um one two all the way up to p - one are +actually relatively + + align:start position:0% +actually relatively + + + align:start position:0% +actually relatively +prime to + + align:start position:0% + + + + align:start position:0% + +P so why is that well p is prime right + + align:start position:0% +P so why is that well p is prime right + + + align:start position:0% +P so why is that well p is prime right +so the greatest common divisor between + + align:start position:0% +so the greatest common divisor between + + + align:start position:0% +so the greatest common divisor between +any of those with p is equal to one + + align:start position:0% +any of those with p is equal to one + + + align:start position:0% +any of those with p is equal to one +that's a definition of relatively prime + + align:start position:0% +that's a definition of relatively prime + + + align:start position:0% +that's a definition of relatively prime +and we know uh that um we can now uh + + align:start position:0% +and we know uh that um we can now uh + + + align:start position:0% +and we know uh that um we can now uh +apply uh ear theorem over here and see + + align:start position:0% +apply uh ear theorem over here and see + + + align:start position:0% +apply uh ear theorem over here and see +that uh K to the power + + align:start position:0% +that uh K to the power + + + align:start position:0% +that uh K to the power +F of + + align:start position:0% +F of + + + align:start position:0% +F of +p is is of course congruent to one + + align:start position:0% +p is is of course congruent to one + + + align:start position:0% +p is is of course congruent to one +modulo uh P that's ear theorem but now + + align:start position:0% +modulo uh P that's ear theorem but now + + + align:start position:0% +modulo uh P that's ear theorem but now +since we know that these are the exact + + align:start position:0% +since we know that these are the exact + + + align:start position:0% +since we know that these are the exact +ones that are relatively prime we can + + align:start position:0% +ones that are relatively prime we can + + + align:start position:0% +ones that are relatively prime we can +explicitly compute the aoan function of + + align:start position:0% +explicitly compute the aoan function of + + + align:start position:0% +explicitly compute the aoan function of +P because there are P minus one numbers + + align:start position:0% +P because there are P minus one numbers + + + align:start position:0% +P because there are P minus one numbers +that are relatively prime to P so that's + + align:start position:0% +that are relatively prime to P so that's + + + align:start position:0% +that are relatively prime to P so that's +the definition over here so the number + + align:start position:0% +the definition over here so the number + + + align:start position:0% +the definition over here so the number +of integers in the range one up to P + + align:start position:0% +of integers in the range one up to P + + + align:start position:0% +of integers in the range one up to P +minus one they're all relatively prime + + align:start position:0% +minus one they're all relatively prime + + + align:start position:0% +minus one they're all relatively prime +so we know that + + align:start position:0% + + + + align:start position:0% + +um 5 of p is equal to P minus + + align:start position:0% +um 5 of p is equal to P minus + + + align:start position:0% +um 5 of p is equal to P minus +one so now we have shown that uh K to ^ + + align:start position:0% +one so now we have shown that uh K to ^ + + + align:start position:0% +one so now we have shown that uh K to ^ +P minus 1 is congruent to one modulo + + align:start position:0% +P minus 1 is congruent to one modulo + + + align:start position:0% +P minus 1 is congruent to one modulo +K now this is kind of interesting + + align:start position:0% +K now this is kind of interesting + + + align:start position:0% +K now this is kind of interesting +because we can use this theorem also to + + align:start position:0% +because we can use this theorem also to + + + align:start position:0% +because we can use this theorem also to +compute the multiplicative inverse of K + + align:start position:0% +compute the multiplicative inverse of K + + + align:start position:0% +compute the multiplicative inverse of K +in this particular case so how how do we + + align:start position:0% +in this particular case so how how do we + + + align:start position:0% +in this particular case so how how do we +do this um we just take uh K and we look + + align:start position:0% +do this um we just take uh K and we look + + + align:start position:0% +do this um we just take uh K and we look +at what happens if you multiply K with K + + align:start position:0% +at what happens if you multiply K with K + + + align:start position:0% +at what happens if you multiply K with K +to ^ P minus + + align:start position:0% +to ^ P minus + + + align:start position:0% +to ^ P minus +2 well this is equal to K to ^ P minus + + align:start position:0% +2 well this is equal to K to ^ P minus + + + align:start position:0% +2 well this is equal to K to ^ P minus +one which is congruent to one + + align:start position:0% +one which is congruent to one + + + align:start position:0% +one which is congruent to one +modulo + + align:start position:0% +modulo + + + align:start position:0% +modulo +p according to our uh according to from + + align:start position:0% +p according to our uh according to from + + + align:start position:0% +p according to our uh according to from +us theorem so now when we look at the + + align:start position:0% +us theorem so now when we look at the + + + align:start position:0% +us theorem so now when we look at the +definition of multiplicative + + align:start position:0% +definition of multiplicative + + + align:start position:0% +definition of multiplicative +inverse over here we see that uh K to ^ + + align:start position:0% +inverse over here we see that uh K to ^ + + + align:start position:0% +inverse over here we see that uh K to ^ +P minus 2 is actually the multiplicative + + align:start position:0% +P minus 2 is actually the multiplicative + + + align:start position:0% +P minus 2 is actually the multiplicative +inverse of + + align:start position:0% +inverse of + + + align:start position:0% +inverse of +K so K inverse is actually equal to k^ P + + align:start position:0% +K so K inverse is actually equal to k^ P + + + align:start position:0% +K so K inverse is actually equal to k^ P +minus + + align:start position:0% +minus + + + align:start position:0% +minus + + align:start position:0% + + + align:start position:0% +modulo + + align:start position:0% +modulo + + + align:start position:0% +modulo +K all right so this theorem we're going + + align:start position:0% +K all right so this theorem we're going + + + align:start position:0% +K all right so this theorem we're going +to use now in the description of + + align:start position:0% + + + + align:start position:0% + +RSA as I said it was uh um only decades + + align:start position:0% +RSA as I said it was uh um only decades + + + align:start position:0% +RSA as I said it was uh um only decades +later after touring um reest Shamir and + + align:start position:0% +later after touring um reest Shamir and + + + align:start position:0% +later after touring um reest Shamir and +adaman were the first to really show how + + align:start position:0% +adaman were the first to really show how + + + align:start position:0% +adaman were the first to really show how +number Theory could be applied so + + align:start position:0% +number Theory could be applied so + + + align:start position:0% +number Theory could be applied so +successfully in cryptography and they + + align:start position:0% +successfully in cryptography and they + + + align:start position:0% +successfully in cryptography and they +essentially showed the first public key + + align:start position:0% +essentially showed the first public key + + + align:start position:0% +essentially showed the first public key +encryption scheme in which a sender and + + align:start position:0% +encryption scheme in which a sender and + + + align:start position:0% +encryption scheme in which a sender and +receiver do not necessarily have to + + align:start position:0% +receiver do not necessarily have to + + + align:start position:0% +receiver do not necessarily have to +exchange a secret key that's not + + align:start position:0% +exchange a secret key that's not + + + align:start position:0% +exchange a secret key that's not +necessary so they had a public key + + align:start position:0% +necessary so they had a public key + + + align:start position:0% +necessary so they had a public key +method and that's still used today and + + align:start position:0% +method and that's still used today and + + + align:start position:0% +method and that's still used today and +it's uh yeah it's a great invention so + + align:start position:0% +it's uh yeah it's a great invention so + + + align:start position:0% +it's uh yeah it's a great invention so +how does RSA + + align:start position:0% +how does RSA + + + align:start position:0% +how does RSA +work uh again we have to talk within an + + align:start position:0% +work uh again we have to talk within an + + + align:start position:0% +work uh again we have to talk within an +encryption scheme about what happens + + align:start position:0% +encryption scheme about what happens + + + align:start position:0% +encryption scheme about what happens +beforehand so + + align:start position:0% +beforehand so + + + align:start position:0% +beforehand so +beforehand we need to generate this + + align:start position:0% +beforehand we need to generate this + + + align:start position:0% +beforehand we need to generate this +public key in the secret + + align:start position:0% +public key in the secret + + + align:start position:0% +public key in the secret +key so the idea is that the + + align:start position:0% +key so the idea is that the + + + align:start position:0% +key so the idea is that the +receiver uh creates + + align:start position:0% +receiver uh creates + + + align:start position:0% +receiver uh creates +a public + + align:start position:0% + + + + align:start position:0% + +key and also a secret + + align:start position:0% +key and also a secret + + + align:start position:0% +key and also a secret +key + + align:start position:0% +key + + + align:start position:0% +key +um he will publish the public key and he + + align:start position:0% +um he will publish the public key and he + + + align:start position:0% +um he will publish the public key and he +will keep the secret key for himself and + + align:start position:0% +will keep the secret key for himself and + + + align:start position:0% +will keep the secret key for himself and +now anybody can uses the public key to + + align:start position:0% +now anybody can uses the public key to + + + align:start position:0% +now anybody can uses the public key to +encrypt a + + align:start position:0% +encrypt a + + + align:start position:0% +encrypt a +message the encrypted message message is + + align:start position:0% +message the encrypted message message is + + + align:start position:0% +message the encrypted message message is +sent to the receiver and he is going to + + align:start position:0% +sent to the receiver and he is going to + + + align:start position:0% +sent to the receiver and he is going to +use his secret key to get back to the + + align:start position:0% +use his secret key to get back to the + + + align:start position:0% +use his secret key to get back to the +plane message + + align:start position:0% +plane message + + + align:start position:0% +plane message +so how is he going to do this well in + + align:start position:0% +so how is he going to do this well in + + + align:start position:0% +so how is he going to do this well in +the first step um the idea is to + + align:start position:0% +the first step um the idea is to + + + align:start position:0% +the first step um the idea is to +generate uh two distinct + + align:start position:0% +generate uh two distinct + + + align:start position:0% +generate uh two distinct +primes turns out that this can be done + + align:start position:0% +primes turns out that this can be done + + + align:start position:0% +primes turns out that this can be done +in a very efficient + + align:start position:0% +in a very efficient + + + align:start position:0% +in a very efficient +way uh there are lots of primes among + + align:start position:0% +way uh there are lots of primes among + + + align:start position:0% +way uh there are lots of primes among +the integers so it just sample and it + + align:start position:0% +the integers so it just sample and it + + + align:start position:0% +the integers so it just sample and it +turns out that you can test + + align:start position:0% +turns out that you can test + + + align:start position:0% +turns out that you can test +primality + + align:start position:0% +primality + + + align:start position:0% +primality +um with a pretty high probability very + + align:start position:0% +um with a pretty high probability very + + + align:start position:0% +um with a pretty high probability very +efficiently and recently actually there + + align:start position:0% +efficiently and recently actually there + + + align:start position:0% +efficiently and recently actually there +has been a deter istic algorithm uh that + + align:start position:0% +has been a deter istic algorithm uh that + + + align:start position:0% +has been a deter istic algorithm uh that +is polinomial in a number of bits of the + + align:start position:0% +is polinomial in a number of bits of the + + + align:start position:0% +is polinomial in a number of bits of the +primes that can actually tell you + + align:start position:0% +primes that can actually tell you + + + align:start position:0% +primes that can actually tell you +whether you have a prime or not so you + + align:start position:0% +whether you have a prime or not so you + + + align:start position:0% +whether you have a prime or not so you +can do + + align:start position:0% +can do + + + align:start position:0% +can do +this two we are going to create a + + align:start position:0% +this two we are going to create a + + + align:start position:0% +this two we are going to create a +product of these two distinct primes and + + align:start position:0% +product of these two distinct primes and + + + align:start position:0% +product of these two distinct primes and +that's where our assumption is going to + + align:start position:0% +that's where our assumption is going to + + + align:start position:0% +that's where our assumption is going to +help us uh that it is hard to factor a + + align:start position:0% +help us uh that it is hard to factor a + + + align:start position:0% +help us uh that it is hard to factor a +product of two large primes that's going + + align:start position:0% +product of two large primes that's going + + + align:start position:0% +product of two large primes that's going +to be the underlying hardness Assumption + + align:start position:0% +to be the underlying hardness Assumption + + + align:start position:0% +to be the underlying hardness Assumption +of the r RSA encryption + + align:start position:0% +of the r RSA encryption + + + align:start position:0% +of the r RSA encryption +scheme so let N be + + align:start position:0% +scheme so let N be + + + align:start position:0% +scheme so let N be +this uh + + align:start position:0% +this uh + + + align:start position:0% +this uh +three uh we're going to + + align:start position:0% +three uh we're going to + + + align:start position:0% +three uh we're going to +select an uh integer e such that the + + align:start position:0% +select an uh integer e such that the + + + align:start position:0% +select an uh integer e such that the +greatest common divisor of e with the + + align:start position:0% +greatest common divisor of e with the + + + align:start position:0% +greatest common divisor of e with the +product P minus1 * Q - + + align:start position:0% +product P minus1 * Q - + + + align:start position:0% +product P minus1 * Q - +one is actually equal to one + + align:start position:0% +one is actually equal to one + + + align:start position:0% +one is actually equal to one +and the public and and once we have + + align:start position:0% +and the public and and once we have + + + align:start position:0% +and the public and and once we have +created + + align:start position:0% +created + + + align:start position:0% +created +this the public key is going to be a + + align:start position:0% +this the public key is going to be a + + + align:start position:0% +this the public key is going to be a +pair um so is the + + align:start position:0% + + + + align:start position:0% + +pair that consists of e itself together + + align:start position:0% +pair that consists of e itself together + + + align:start position:0% +pair that consists of e itself together +with + + align:start position:0% +with + + + align:start position:0% +with +n so that's a public key and the secret + + align:start position:0% +n so that's a public key and the secret + + + align:start position:0% +n so that's a public key and the secret +key is going to be uh computed as + + align:start position:0% +key is going to be uh computed as + + + align:start position:0% +key is going to be uh computed as +follows in step + + align:start position:0% +follows in step + + + align:start position:0% +follows in step +four we going to compute + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +D such that D * e is congruent to one + + align:start position:0% + + + + align:start position:0% + +modulo uh that product of P minus one * + + align:start position:0% +modulo uh that product of P minus one * + + + align:start position:0% +modulo uh that product of P minus one * +Q minus + + align:start position:0% +Q minus + + + align:start position:0% +Q minus +one uh can we do this yeah because the + + align:start position:0% +one uh can we do this yeah because the + + + align:start position:0% +one uh can we do this yeah because the +greatest common divisor between e and + + align:start position:0% +greatest common divisor between e and + + + align:start position:0% +greatest common divisor between e and +that product is equal to + + align:start position:0% +that product is equal to + + + align:start position:0% +that product is equal to +one and we have shown over here that + + align:start position:0% +one and we have shown over here that + + + align:start position:0% +one and we have shown over here that +therefore it has a multiplicative + + align:start position:0% +therefore it has a multiplicative + + + align:start position:0% +therefore it has a multiplicative +inverse so first of all we know that the + + align:start position:0% +inverse so first of all we know that the + + + align:start position:0% +inverse so first of all we know that the +solution D exists and we can also + + align:start position:0% +solution D exists and we can also + + + align:start position:0% +solution D exists and we can also +efficiently + + align:start position:0% +efficiently + + + align:start position:0% +efficiently +computed so um the secret key is going + + align:start position:0% +computed so um the secret key is going + + + align:start position:0% +computed so um the secret key is going +to be the + + align:start position:0% + + + + align:start position:0% + +pair that consists of D and also n so + + align:start position:0% +pair that consists of D and also n so + + + align:start position:0% +pair that consists of D and also n so +how does it work the uh sender is knows + + align:start position:0% +how does it work the uh sender is knows + + + align:start position:0% +how does it work the uh sender is knows +the public key e and n and uses those to + + align:start position:0% +the public key e and n and uses those to + + + align:start position:0% +the public key e and n and uses those to +encrypt a message I will explain it in a + + align:start position:0% +encrypt a message I will explain it in a + + + align:start position:0% +encrypt a message I will explain it in a +moment and then uh the uh receiver knows + + align:start position:0% +moment and then uh the uh receiver knows + + + align:start position:0% +moment and then uh the uh receiver knows +the secret key d and n and then is able + + align:start position:0% +the secret key d and n and then is able + + + align:start position:0% +the secret key d and n and then is able +to decrypt it okay so let's see how + + align:start position:0% +to decrypt it okay so let's see how + + + align:start position:0% +to decrypt it okay so let's see how +encryption + + align:start position:0% +encryption + + + align:start position:0% +encryption +works and then we will have to do a lot + + align:start position:0% +works and then we will have to do a lot + + + align:start position:0% +works and then we will have to do a lot +of mathematics to get the decryption + + align:start position:0% +of mathematics to get the decryption + + + align:start position:0% +of mathematics to get the decryption +going so M Prime which is uh is computed + + align:start position:0% +going so M Prime which is uh is computed + + + align:start position:0% +going so M Prime which is uh is computed +so the encrypted plain text is computed + + align:start position:0% +so the encrypted plain text is computed + + + align:start position:0% +so the encrypted plain text is computed +as the remainder of n to the power e + + align:start position:0% +as the remainder of n to the power e + + + align:start position:0% +as the remainder of n to the power e +which is part of the public key and then + + align:start position:0% +which is part of the public key and then + + + align:start position:0% +which is part of the public key and then +the finding out as many multiples of n + + align:start position:0% +the finding out as many multiples of n + + + align:start position:0% +the finding out as many multiples of n +as + + align:start position:0% +as + + + align:start position:0% +as +possible it turns out and we're going to + + align:start position:0% +possible it turns out and we're going to + + + align:start position:0% +possible it turns out and we're going to +prove this that decryption works as + + align:start position:0% +prove this that decryption works as + + + align:start position:0% +prove this that decryption works as +follows uh we can compute M by using M + + align:start position:0% +follows uh we can compute M by using M + + + align:start position:0% +follows uh we can compute M by using M +Prime so we receive M Prime what do we + + align:start position:0% +Prime so we receive M Prime what do we + + + align:start position:0% +Prime so we receive M Prime what do we +do we're going to take mime Prime raise + + align:start position:0% +do we're going to take mime Prime raise + + + align:start position:0% +do we're going to take mime Prime raise +it to the power D which is uh part of + + align:start position:0% +it to the power D which is uh part of + + + align:start position:0% +it to the power D which is uh part of +the secret key and then dividing out as + + align:start position:0% +the secret key and then dividing out as + + + align:start position:0% +the secret key and then dividing out as +many multiples of + + align:start position:0% +many multiples of + + + align:start position:0% +many multiples of +n now why would that + + align:start position:0% +n now why would that + + + align:start position:0% +n now why would that +work why would uh why would this work so + + align:start position:0% +work why would uh why would this work so + + + align:start position:0% +work why would uh why would this work so +let's prove uh this step over + + align:start position:0% + + + + align:start position:0% + +here well it turns out that we can apply + + align:start position:0% +here well it turns out that we can apply + + + align:start position:0% +here well it turns out that we can apply +fmat + + align:start position:0% +fmat + + + align:start position:0% +fmat +theorem and the IDE is as follows so + + align:start position:0% +theorem and the IDE is as follows so + + + align:start position:0% +theorem and the IDE is as follows so +let's have a look we know that M Prime + + align:start position:0% +let's have a look we know that M Prime + + + align:start position:0% +let's have a look we know that M Prime +is equal to the remainder of M ra to + + align:start position:0% +is equal to the remainder of M ra to + + + align:start position:0% +is equal to the remainder of M ra to +the^ + + align:start position:0% +the^ + + + align:start position:0% +the^ +e uh which is congruent to M the power e + + align:start position:0% +e uh which is congruent to M the power e + + + align:start position:0% +e uh which is congruent to M the power e +modulo + + align:start position:0% +modulo + + + align:start position:0% +modulo +n we have seen this now a number of + + align:start position:0% +n we have seen this now a number of + + + align:start position:0% +n we have seen this now a number of +times + + align:start position:0% +times + + + align:start position:0% +times +right so what does this imply this + + align:start position:0% +right so what does this imply this + + + align:start position:0% +right so what does this imply this +implies that M + + align:start position:0% +implies that M + + + align:start position:0% +implies that M +Prime to the power D is actually equal + + align:start position:0% +Prime to the power D is actually equal + + + align:start position:0% +Prime to the power D is actually equal +is congruent to m to the power e + + align:start position:0% +is congruent to m to the power e + + + align:start position:0% +is congruent to m to the power e +to the power D so I just raise this side + + align:start position:0% +to the power D so I just raise this side + + + align:start position:0% +to the power D so I just raise this side +to the power D and I raise this side to + + align:start position:0% +to the power D and I raise this side to + + + align:start position:0% +to the power D and I raise this side to +the power D and I + + align:start position:0% +the power D and I + + + align:start position:0% +the power D and I +still um and I know now that M Prime to + + align:start position:0% +still um and I know now that M Prime to + + + align:start position:0% +still um and I know now that M Prime to +the^ D is equal to M the power e d + + align:start position:0% +the^ D is equal to M the power e d + + + align:start position:0% +the^ D is equal to M the power e d +congruent to M the^ Ed modul + + align:start position:0% +congruent to M the^ Ed modul + + + align:start position:0% +congruent to M the^ Ed modul +n so now we know that there exists an + + align:start position:0% +n so now we know that there exists an + + + align:start position:0% +n so now we know that there exists an +integer R uh we are going to use the + + align:start position:0% +integer R uh we are going to use the + + + align:start position:0% +integer R uh we are going to use the +fact that we have that e and P minus1 * + + align:start position:0% +fact that we have that e and P minus1 * + + + align:start position:0% +fact that we have that e and P minus1 * +Q -1 have a greatest common divisor of + + align:start position:0% +Q -1 have a greatest common divisor of + + + align:start position:0% +Q -1 have a greatest common divisor of +one so we know that e * + + align:start position:0% +one so we know that e * + + + align:start position:0% +one so we know that e * +D is actually equal to uh 1 + r + + align:start position:0% +D is actually equal to uh 1 + r + + + align:start position:0% +D is actually equal to uh 1 + r +* P - 1 * Q - 1 actually what I use here + + align:start position:0% +* P - 1 * Q - 1 actually what I use here + + + align:start position:0% +* P - 1 * Q - 1 actually what I use here +is uh the fact is this over here by the + + align:start position:0% +is uh the fact is this over here by the + + + align:start position:0% +is uh the fact is this over here by the +definition of congruency I know that the + + align:start position:0% +definition of congruency I know that the + + + align:start position:0% +definition of congruency I know that the +difference between those two D * e and + + align:start position:0% +difference between those two D * e and + + + align:start position:0% +difference between those two D * e and +one is divisible by this product so I + + align:start position:0% +one is divisible by this product so I + + + align:start position:0% +one is divisible by this product so I +know that there exists an integer such + + align:start position:0% +know that there exists an integer such + + + align:start position:0% +know that there exists an integer such +that e * D equals 1 plus a multiple of + + align:start position:0% +that e * D equals 1 plus a multiple of + + + align:start position:0% +that e * D equals 1 plus a multiple of +that product that's how it + + align:start position:0% +that product that's how it + + + align:start position:0% +that product that's how it +works + + align:start position:0% +works + + + align:start position:0% +works +so we know that M Prime to the power D + + align:start position:0% +so we know that M Prime to the power D + + + align:start position:0% +so we know that M Prime to the power D +we already saw that it is equal to m to + + align:start position:0% +we already saw that it is equal to m to + + + align:start position:0% +we already saw that it is equal to m to +the power + + align:start position:0% +the power + + + align:start position:0% +the power +Ed um which is congruent to well we just + + align:start position:0% +Ed um which is congruent to well we just + + + align:start position:0% +Ed um which is congruent to well we just +replace Ed by 1 + r * this multiple so + + align:start position:0% +replace Ed by 1 + r * this multiple so + + + align:start position:0% +replace Ed by 1 + r * this multiple so +we have m ^ + + align:start position:0% +we have m ^ + + + align:start position:0% +we have m ^ +1 * m to the power this part are p min-1 + + align:start position:0% +1 * m to the power this part are p min-1 + + + align:start position:0% +1 * m to the power this part are p min-1 +q + + align:start position:0% + + + + align:start position:0% + +-1 + + align:start position:0% +-1 + + + align:start position:0% +-1 +okay so now we're finally uh going to uh + + align:start position:0% +okay so now we're finally uh going to uh + + + align:start position:0% +okay so now we're finally uh going to uh +get to fma's theorem we know that n is + + align:start position:0% +get to fma's theorem we know that n is + + + align:start position:0% +get to fma's theorem we know that n is +the product of p and + + align:start position:0% +the product of p and + + + align:start position:0% +the product of p and +Q and um I'm not actually sure why I do + + align:start position:0% +Q and um I'm not actually sure why I do + + + align:start position:0% +Q and um I'm not actually sure why I do +this here + + align:start position:0% +this here + + + align:start position:0% +this here +but okay so + + align:start position:0% +but okay so + + + align:start position:0% +but okay so +so let's apply FMA theorem and see how + + align:start position:0% +so let's apply FMA theorem and see how + + + align:start position:0% +so let's apply FMA theorem and see how +we can use this so if m is not equal is + + align:start position:0% +we can use this so if m is not equal is + + + align:start position:0% +we can use this so if m is not equal is +not congruent to zero modul + + align:start position:0% + + + + align:start position:0% + +P well then we can apply for a theorem + + align:start position:0% +P well then we can apply for a theorem + + + align:start position:0% +P well then we can apply for a theorem +um where is it it's it's over here uh we + + align:start position:0% +um where is it it's it's over here uh we + + + align:start position:0% +um where is it it's it's over here uh we +can only apply this if K is in the range + + align:start position:0% +can only apply this if K is in the range + + + align:start position:0% +can only apply this if K is in the range +from 1 to P Min - one is not equal to + + align:start position:0% +from 1 to P Min - one is not equal to + + + align:start position:0% +from 1 to P Min - one is not equal to +zero so if m is not equal to zero not + + align:start position:0% +zero so if m is not equal to zero not + + + align:start position:0% +zero so if m is not equal to zero not +congruent to Z modul P then we can apply + + align:start position:0% +congruent to Z modul P then we can apply + + + align:start position:0% +congruent to Z modul P then we can apply +the theorem and state that m ^ p minus1 + + align:start position:0% +the theorem and state that m ^ p minus1 + + + align:start position:0% +the theorem and state that m ^ p minus1 +is congruent to one modulo + + align:start position:0% +is congruent to one modulo + + + align:start position:0% +is congruent to one modulo +p and in the same + + align:start position:0% +p and in the same + + + align:start position:0% +p and in the same +way we can do this for Q so if this is + + align:start position:0% +way we can do this for Q so if this is + + + align:start position:0% +way we can do this for Q so if this is +not true + + align:start position:0% +not true + + + align:start position:0% +not true +modulo + + align:start position:0% +modulo + + + align:start position:0% +modulo +Q then m to the power Q minus one is + + align:start position:0% +Q then m to the power Q minus one is + + + align:start position:0% +Q then m to the power Q minus one is +congruent to one + + align:start position:0% +congruent to one + + + align:start position:0% +congruent to one +modulo Q so here we have used forat + + align:start position:0% +modulo Q so here we have used forat + + + align:start position:0% +modulo Q so here we have used forat +theorem + + align:start position:0% + + + + align:start position:0% + +twice now we can apply uh what we have + + align:start position:0% +twice now we can apply uh what we have + + + align:start position:0% +twice now we can apply uh what we have +learned before uh which is uh what we + + align:start position:0% +learned before uh which is uh what we + + + align:start position:0% +learned before uh which is uh what we +wrote down over here M Prime to the + + align:start position:0% +wrote down over here M Prime to the + + + align:start position:0% +wrote down over here M Prime to the +power D is congruent to This modulo n + + align:start position:0% +power D is congruent to This modulo n + + + align:start position:0% +power D is congruent to This modulo n +now n is p * Q so let's have a look what + + align:start position:0% +now n is p * Q so let's have a look what + + + align:start position:0% +now n is p * Q so let's have a look what +that means it means + + align:start position:0% +that means it means + + + align:start position:0% +that means it means +that since N is a product of p and Q we + + align:start position:0% +that since N is a product of p and Q we + + + align:start position:0% +that since N is a product of p and Q we +can also look at this + + align:start position:0% +can also look at this + + + align:start position:0% +can also look at this +congruent modul P so in + + align:start position:0% +congruent modul P so in + + + align:start position:0% +congruent modul P so in +particular we know that M Prime to the + + align:start position:0% +particular we know that M Prime to the + + + align:start position:0% +particular we know that M Prime to the +power D is congruent to M * m r p -1 * Q + + align:start position:0% +power D is congruent to M * m r p -1 * Q + + + align:start position:0% +power D is congruent to M * m r p -1 * Q +-1 + + align:start position:0% +-1 + + + align:start position:0% +-1 +modulo P why is that well we know that n + + align:start position:0% +modulo P why is that well we know that n + + + align:start position:0% +modulo P why is that well we know that n +divides this Difference by the + + align:start position:0% +divides this Difference by the + + + align:start position:0% +divides this Difference by the +definition of + + align:start position:0% +definition of + + + align:start position:0% +definition of +congruency n is equal to P * Q so if n + + align:start position:0% +congruency n is equal to P * Q so if n + + + align:start position:0% +congruency n is equal to P * Q so if n +divides is is is dividing this + + align:start position:0% +divides is is is dividing this + + + align:start position:0% +divides is is is dividing this +difference also p is dividing this + + align:start position:0% +difference also p is dividing this + + + align:start position:0% +difference also p is dividing this +difference so that's why we can write it + + align:start position:0% +difference so that's why we can write it + + + align:start position:0% +difference so that's why we can write it +m Prime to the^ D is congruent to this + + align:start position:0% +m Prime to the^ D is congruent to this + + + align:start position:0% +m Prime to the^ D is congruent to this +thing modul + + align:start position:0% +thing modul + + + align:start position:0% +thing modul +p and of course we can uh repeat this + + align:start position:0% +p and of course we can uh repeat this + + + align:start position:0% +p and of course we can uh repeat this +for + + align:start position:0% +for + + + align:start position:0% +for +Q so let me write this out as + + align:start position:0% + + + + align:start position:0% + +well so there it + + align:start position:0% + + + + align:start position:0% + +is so now we can um uh use what we have + + align:start position:0% +is so now we can um uh use what we have + + + align:start position:0% +is so now we can um uh use what we have +figured out over here so we know that if + + align:start position:0% +figured out over here so we know that if + + + align:start position:0% +figured out over here so we know that if +m is not equal to + + align:start position:0% +m is not equal to + + + align:start position:0% +m is not equal to +zero then this thing over + + align:start position:0% +zero then this thing over + + + align:start position:0% +zero then this thing over +here cancels out because m ^ P minus one + + align:start position:0% +here cancels out because m ^ P minus one + + + align:start position:0% +here cancels out because m ^ P minus one +is congruent to + + align:start position:0% +is congruent to + + + align:start position:0% +is congruent to +one so we have that M Prime to the power + + align:start position:0% +one so we have that M Prime to the power + + + align:start position:0% +one so we have that M Prime to the power +D is congruent to + + align:start position:0% +D is congruent to + + + align:start position:0% +D is congruent to +m modulo + + align:start position:0% +m modulo + + + align:start position:0% +m modulo +p if m is not congruent to zero modul P + + align:start position:0% +p if m is not congruent to zero modul P + + + align:start position:0% +p if m is not congruent to zero modul P +right because if m is not congruent to + + align:start position:0% +right because if m is not congruent to + + + align:start position:0% +right because if m is not congruent to +zero we have this particular equation we + + align:start position:0% +zero we have this particular equation we + + + align:start position:0% +zero we have this particular equation we +plug it in over here this all cancels + + align:start position:0% +plug it in over here this all cancels + + + align:start position:0% +plug it in over here this all cancels +and we just leave or left with M now if + + align:start position:0% +and we just leave or left with M now if + + + align:start position:0% +and we just leave or left with M now if +m is equal is congruent to zero modulo P + + align:start position:0% +m is equal is congruent to zero modulo P + + + align:start position:0% +m is equal is congruent to zero modulo P +well then we can see that it is equal to + + align:start position:0% +well then we can see that it is equal to + + + align:start position:0% +well then we can see that it is equal to +zero so it's equal to zero so this + + align:start position:0% +zero so it's equal to zero so this + + + align:start position:0% +zero so it's equal to zero so this +actually holds for any + + align:start position:0% +actually holds for any + + + align:start position:0% +actually holds for any +case now we can do the same for a q + + align:start position:0% +case now we can do the same for a q + + + align:start position:0% +case now we can do the same for a q +the same + + align:start position:0% +the same + + + align:start position:0% +the same +argument and show that this must + + align:start position:0% +argument and show that this must + + + align:start position:0% +argument and show that this must +hold so now we know that P divides the + + align:start position:0% +hold so now we know that P divides the + + + align:start position:0% +hold so now we know that P divides the +difference of M Prime D minus m q is + + align:start position:0% +difference of M Prime D minus m q is + + + align:start position:0% +difference of M Prime D minus m q is +another Prime that divides this + + align:start position:0% +another Prime that divides this + + + align:start position:0% +another Prime that divides this +difference and the only way that that is + + align:start position:0% +difference and the only way that that is + + + align:start position:0% +difference and the only way that that is +possible is If the product of p and Q is + + align:start position:0% +possible is If the product of p and Q is + + + align:start position:0% +possible is If the product of p and Q is +dividing both is dividing this + + align:start position:0% +dividing both is dividing this + + + align:start position:0% +dividing both is dividing this +particular number this difference and we + + align:start position:0% +particular number this difference and we + + + align:start position:0% +particular number this difference and we +have two different primes that dividing + + align:start position:0% +have two different primes that dividing + + + align:start position:0% +have two different primes that dividing +the same number so the product must + + align:start position:0% +the same number so the product must + + + align:start position:0% +the same number so the product must +divide it so P * Q divides M Prime + + align:start position:0% +divide it so P * Q divides M Prime + + + align:start position:0% +divide it so P * Q divides M Prime +D minus + + align:start position:0% +D minus + + + align:start position:0% +D minus +M oh but P * Q is equal to + + align:start position:0% +M oh but P * Q is equal to + + + align:start position:0% +M oh but P * Q is equal to +n so now we're almost done because now + + align:start position:0% +n so now we're almost done because now + + + align:start position:0% +n so now we're almost done because now +we can state by the definition of + + align:start position:0% +we can state by the definition of + + + align:start position:0% +we can state by the definition of +congruency that M Prime to the power D + + align:start position:0% +congruency that M Prime to the power D + + + align:start position:0% +congruency that M Prime to the power D +is congruent to m modulo + + align:start position:0% +is congruent to m modulo + + + align:start position:0% +is congruent to m modulo +n now since m is a message that is in + + align:start position:0% +n now since m is a message that is in + + + align:start position:0% +n now since m is a message that is in +the range of uh of of of so I did not + + align:start position:0% +the range of uh of of of so I did not + + + align:start position:0% +the range of uh of of of so I did not +write it down here so m is a message + + align:start position:0% +write it down here so m is a message + + + align:start position:0% +write it down here so m is a message +which is in the range of zero all the + + align:start position:0% +which is in the range of zero all the + + + align:start position:0% +which is in the range of zero all the +way up to n minus one we knowe and we + + align:start position:0% +way up to n minus one we knowe and we + + + align:start position:0% +way up to n minus one we knowe and we +have seen that before with Ching's code + + align:start position:0% +have seen that before with Ching's code + + + align:start position:0% +have seen that before with Ching's code +that we can rewrite this and stay and + + align:start position:0% +that we can rewrite this and stay and + + + align:start position:0% +that we can rewrite this and stay and +say that m equals the + + align:start position:0% +say that m equals the + + + align:start position:0% +say that m equals the +remainder of M Prime to the power D + + align:start position:0% +remainder of M Prime to the power D + + + align:start position:0% +remainder of M Prime to the power D +after multiplying out as many multiples + + align:start position:0% +after multiplying out as many multiples + + + align:start position:0% +after multiplying out as many multiples +of n as + + align:start position:0% +of n as + + + align:start position:0% +of n as +possible so here you go so this is the + + align:start position:0% +possible so here you go so this is the + + + align:start position:0% +possible so here you go so this is the +decryption uh Rule and it works we have + + align:start position:0% +decryption uh Rule and it works we have + + + align:start position:0% +decryption uh Rule and it works we have +shown that this equation truly + + align:start position:0% +shown that this equation truly + + + align:start position:0% +shown that this equation truly +holds so RSA has really withstood the + + align:start position:0% +holds so RSA has really withstood the + + + align:start position:0% +holds so RSA has really withstood the +test of time it's already out there for + + align:start position:0% +test of time it's already out there for + + + align:start position:0% +test of time it's already out there for +many decades and it's still widely used + + align:start position:0% +many decades and it's still widely used + + + align:start position:0% +many decades and it's still widely used +I wanted to talk a little bit about this + + align:start position:0% +I wanted to talk a little bit about this + + + align:start position:0% +I wanted to talk a little bit about this +but there seemed not to be enough time + + align:start position:0% +but there seemed not to be enough time + + + align:start position:0% +but there seemed not to be enough time +but I just like to mention that uh that + + align:start position:0% +but I just like to mention that uh that + + + align:start position:0% +but I just like to mention that uh that +only in 2009 + + align:start position:0% +only in 2009 + + + align:start position:0% +only in 2009 +uh Greg Gentry proved a beautiful + + align:start position:0% +uh Greg Gentry proved a beautiful + + + align:start position:0% +uh Greg Gentry proved a beautiful +theorem and was able to evaluate uh + + align:start position:0% +theorem and was able to evaluate uh + + + align:start position:0% +theorem and was able to evaluate uh +Boolean cirqus or or say a certain type + + align:start position:0% +Boolean cirqus or or say a certain type + + + align:start position:0% +Boolean cirqus or or say a certain type +of programs under encryption so you can + + align:start position:0% +of programs under encryption so you can + + + align:start position:0% +of programs under encryption so you can +sort of add and multiply cyer text + + align:start position:0% +sort of add and multiply cyer text + + + align:start position:0% +sort of add and multiply cyer text +encryptions together and it is as if you + + align:start position:0% +encryptions together and it is as if you + + + align:start position:0% +encryptions together and it is as if you +multiply them at the plain text level + + align:start position:0% +multiply them at the plain text level + + + align:start position:0% +multiply them at the plain text level +that was a fantastic uh that was an + + align:start position:0% +that was a fantastic uh that was an + + + align:start position:0% +that was a fantastic uh that was an +enormous open problem and he solved it + + align:start position:0% +enormous open problem and he solved it + + + align:start position:0% +enormous open problem and he solved it +and only a few months earlier in 20 10 + + align:start position:0% +and only a few months earlier in 20 10 + + + align:start position:0% +and only a few months earlier in 20 10 +in joint work with Greg and some other + + align:start position:0% +in joint work with Greg and some other + + + align:start position:0% +in joint work with Greg and some other +colleagues at IBM we showed it with very + + align:start position:0% +colleagues at IBM we showed it with very + + + align:start position:0% +colleagues at IBM we showed it with very +simple arithmetic that just uses modulo + + align:start position:0% +simple arithmetic that just uses modulo + + + align:start position:0% +simple arithmetic that just uses modulo +p and modulo 2 kind of things we could + + align:start position:0% +p and modulo 2 kind of things we could + + + align:start position:0% +p and modulo 2 kind of things we could +show a construction that uses uh such + + align:start position:0% +show a construction that uses uh such + + + align:start position:0% +show a construction that uses uh such +that has such a property such an + + align:start position:0% +that has such a property such an + + + align:start position:0% +that has such a property such an +encryption scheme over the integers so + + align:start position:0% +encryption scheme over the integers so + + + align:start position:0% +encryption scheme over the integers so +there's still a lot of stuff going on in + + align:start position:0% +there's still a lot of stuff going on in + + + align:start position:0% +there's still a lot of stuff going on in +this area and really we use this type of + + align:start position:0% +this area and really we use this type of + + + align:start position:0% +this area and really we use this type of +very basic stuff the problem in + + align:start position:0% +very basic stuff the problem in + + + align:start position:0% +very basic stuff the problem in +cryptography is to show that is secure + + align:start position:0% +cryptography is to show that is secure + + + align:start position:0% +cryptography is to show that is secure +so we have to show that uh breaking the + + align:start position:0% +so we have to show that uh breaking the + + + align:start position:0% +so we have to show that uh breaking the +scheme needs to be reduced to some + + align:start position:0% +scheme needs to be reduced to some + + + align:start position:0% +scheme needs to be reduced to some +really hard problem and that is us and + + align:start position:0% +really hard problem and that is us and + + + align:start position:0% +really hard problem and that is us and +that's always the really difficult part + + align:start position:0% +that's always the really difficult part + + + align:start position:0% +that's always the really difficult part +of such type of research okay well have + + align:start position:0% +of such type of research okay well have + + + align:start position:0% +of such type of research okay well have +lots of fun with the recitation \ No newline at end of file diff --git a/ZWdDKll8qZc.txt b/ZWdDKll8qZc.txt new file mode 100644 index 0000000000000000000000000000000000000000..d620f7941361a850f02c5d5268b30c29d5ac5ff8 --- /dev/null +++ b/ZWdDKll8qZc.txt @@ -0,0 +1,234 @@ +LORNA GIBSON: So I think +one of the special things + +about this course +and about my kind + +of research on +cellular materials + +is that I spend a fair +amount of time talking + +about materials in nature. + +So I talk about wood, +for instance, and what + +it is about the cellular +structure that gives rise + +to the density dependence +of wood properties + +and the anisotropy +in wood properties. + +I talk about +trabecular bone, and I + +talk about the structure +and properties of the bone, + +but also we do a +little bit of modeling + +on how you might look at +bone loss and osteoporosis. + +So if you lose a certain +fraction of the bone + +density, what residual +strength would + +you expect the bone to have. + +We have a project +on bamboo right now. + +We talk about the +structure of bamboo. + +Bamboo is actually a grass. + +And this is a Chinese species +of bamboo called moso bamboo, + +and you can see how +big this one is. + +They even get bigger, maybe +six or eight inches across. + +And what we're +interested in doing + +is making something called +structural bamboo products. + +And this is an example of a +bamboo oriented strand board. + +So the same way +people take wood, + +and they chop wood +up into strands + +and make oriented strand boards +for housing construction, + +you could, in principal, do +the same thing with bamboo. + +And we have a project +that's in collaboration + +with some colleagues at the +University of British Columbia. + +They're the ones +who are actually + +making the bamboo +oriented strand board. + +And with some architects in +England, in Cambridge, England, + +we're looking at things like how +you might modify wood building + +codes that talk about +wood structural products, + +how you would modify that for +bamboo structural products. + +And what we're +doing here at MIT is + +we're looking at the +structure of the bamboo + +and doing some modeling of +the mechanical properties + +of the bamboo itself. + +So that's one example. + +Here's another example. + +This is a bamboo laminate. + +So this is a little bit like +a glue laminated wood member, + +but in fact, this +one is made out + +of bamboo instead +of out of wood. + +So it's the same kind of idea. + +Let's see. + +We've also had a project +in the past on cork. + +So this is a cork +from a wine bottle, + +and we've looked at that. + +Cork has an unusual +mechanical property. + +You know, if you take a rubber +band and you pull on it, + +if you can make it longer this +way, it gets narrower that way. + +Well, if you load cork +in one direction, if you, + +say, pull on it +or compress it, it + +doesn't get any +wider or narrower + +in the other direction. + +It just stays the +same kind of size. + +And you can show +that that's related + +to the structure of the cells. + +The cells are like +little bellows, + +or like a little concertina. + +So you can imagine if you +have a little concertina, + +and you push on it this +way, it doesn't really + +get any bigger that way +or smaller that way. + +It just stays the +same dimension. + +And the cork cells look +a little bit like that, + +and that's why they do that. + +So we have all these +natural materials. + +We talk a little about +the hierarchical structure + +in plants. + +The cell walls are +fiber composites, + +and then there's a +cellular structure. + +And plant materials have a +sort of hierarchical structure, + +with several different +levels of hierarchy, + +and we talk about that +in the class as well. + +And we talk a +little bit about why + +that makes these materials +mechanically efficient + +and how you might look +at designing engineering + +materials based on that. + +So there's a little bit of +biomimicking in the class + +as well. \ No newline at end of file diff --git a/ZYf0tz9oVz8.txt b/ZYf0tz9oVz8.txt new file mode 100644 index 0000000000000000000000000000000000000000..fe519e9b24b6ed5eaaefe2b746eb1fe7c67227dc --- /dev/null +++ b/ZYf0tz9oVz8.txt @@ -0,0 +1,6203 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT open courseware continue + + align:start position:0% +will help MIT open courseware continue + + + align:start position:0% +will help MIT open courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free to make a donation or + + align:start position:0% +resources for free to make a donation or + + + align:start position:0% +resources for free to make a donation or +view additional materials from hundreds + + align:start position:0% +view additional materials from hundreds + + + align:start position:0% +view additional materials from hundreds +of MIT courses visit MIT opencourseware + + align:start position:0% +of MIT courses visit MIT opencourseware + + + align:start position:0% +of MIT courses visit MIT opencourseware +at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +hi Welcome to our final lecture in part + + align:start position:0% +hi Welcome to our final lecture in part + + + align:start position:0% +hi Welcome to our final lecture in part +three of calculus and I suppose it would + + align:start position:0% +three of calculus and I suppose it would + + + align:start position:0% +three of calculus and I suppose it would +be nice to have an appropriate story to + + align:start position:0% +be nice to have an appropriate story to + + + align:start position:0% +be nice to have an appropriate story to +tell and the only story I can think of + + align:start position:0% +tell and the only story I can think of + + + align:start position:0% +tell and the only story I can think of +is on the transatlantic flight the + + align:start position:0% +is on the transatlantic flight the + + + align:start position:0% +is on the transatlantic flight the +steward is coming in to the passengers + + align:start position:0% +steward is coming in to the passengers + + + align:start position:0% +steward is coming in to the passengers +cabin Midway over the Atlantic Ocean and + + align:start position:0% +cabin Midway over the Atlantic Ocean and + + + align:start position:0% +cabin Midway over the Atlantic Ocean and +saying to the passengers well I have + + align:start position:0% +saying to the passengers well I have + + + align:start position:0% +saying to the passengers well I have +some good news and some bad news for you + + align:start position:0% +some good news and some bad news for you + + + align:start position:0% +some good news and some bad news for you +the bad news is that we're almost out of + + align:start position:0% +the bad news is that we're almost out of + + + align:start position:0% +the bad news is that we're almost out of +gas and the good news is that we're + + align:start position:0% +gas and the good news is that we're + + + align:start position:0% +gas and the good news is that we're +making wonderful time and the reason I + + align:start position:0% +making wonderful time and the reason I + + + align:start position:0% +making wonderful time and the reason I +thought of this particular story is that + + align:start position:0% +thought of this particular story is that + + + align:start position:0% +thought of this particular story is that +in a sense we are not almost out of gas + + align:start position:0% +in a sense we are not almost out of gas + + + align:start position:0% +in a sense we are not almost out of gas +but in terms of this being a + + align:start position:0% +but in terms of this being a + + + align:start position:0% +but in terms of this being a +fundamentalist type of course in which + + align:start position:0% +fundamentalist type of course in which + + + align:start position:0% +fundamentalist type of course in which +we're trying to give the ingredients of + + align:start position:0% +we're trying to give the ingredients of + + + align:start position:0% +we're trying to give the ingredients of +what goes into all advanced mathematics + + align:start position:0% +what goes into all advanced mathematics + + + align:start position:0% +what goes into all advanced mathematics +courses we have sort of come to the end + + align:start position:0% +courses we have sort of come to the end + + + align:start position:0% +courses we have sort of come to the end +of the road that we have finished the + + align:start position:0% +of the road that we have finished the + + + align:start position:0% +of the road that we have finished the +so-called ABCs of mathematics as far as + + align:start position:0% +so-called ABCs of mathematics as far as + + + align:start position:0% +so-called ABCs of mathematics as far as +making wonderful time is concerned I + + align:start position:0% +making wonderful time is concerned I + + + align:start position:0% +making wonderful time is concerned I +would say we've done deliberately just + + align:start position:0% +would say we've done deliberately just + + + align:start position:0% +would say we've done deliberately just +the opposite that we have essentially + + align:start position:0% +the opposite that we have essentially + + + align:start position:0% +the opposite that we have essentially +taken one or two Central themes and try + + align:start position:0% +taken one or two Central themes and try + + + align:start position:0% +taken one or two Central themes and try +to unify all of Elementary calculus in + + align:start position:0% +to unify all of Elementary calculus in + + + align:start position:0% +to unify all of Elementary calculus in +terms of these Central themes and when + + align:start position:0% +terms of these Central themes and when + + + align:start position:0% +terms of these Central themes and when +you do something like this it's very + + align:start position:0% +you do something like this it's very + + + align:start position:0% +you do something like this it's very +difficult to come to the end of a course + + align:start position:0% +difficult to come to the end of a course + + + align:start position:0% +difficult to come to the end of a course +you sort of don't know where to stop so + + align:start position:0% +you sort of don't know where to stop so + + + align:start position:0% +you sort of don't know where to stop so +you go back to a little trick that you + + align:start position:0% +you go back to a little trick that you + + + align:start position:0% +you go back to a little trick that you +learned in about the third grade when + + align:start position:0% +learned in about the third grade when + + + align:start position:0% +learned in about the third grade when +you wrote compositions where you learned + + align:start position:0% +you wrote compositions where you learned + + + align:start position:0% +you wrote compositions where you learned +that you could write anything that you + + align:start position:0% +that you could write anything that you + + + align:start position:0% +that you could write anything that you +wanted as long as the last line was we + + align:start position:0% +wanted as long as the last line was we + + + align:start position:0% +wanted as long as the last line was we +all had a very nice time so we now must + + align:start position:0% +all had a very nice time so we now must + + + align:start position:0% +all had a very nice time so we now must +look for a line along those particular + + align:start position:0% +look for a line along those particular + + + align:start position:0% +look for a line along those particular +thoughts and if we recall that we began + + align:start position:0% +thoughts and if we recall that we began + + + align:start position:0% +thoughts and if we recall that we began +as our major theme in this course the + + align:start position:0% +as our major theme in this course the + + + align:start position:0% +as our major theme in this course the +idea of mathematical structure the idea + + align:start position:0% +idea of mathematical structure the idea + + + align:start position:0% +idea of mathematical structure the idea +of what new math really meant not new + + align:start position:0% +of what new math really meant not new + + + align:start position:0% +of what new math really meant not new +meaning brand new but new meaning the + + align:start position:0% +meaning brand new but new meaning the + + + align:start position:0% +meaning brand new but new meaning the +opposite of P new meaning meaningful I + + align:start position:0% +opposite of P new meaning meaningful I + + + align:start position:0% +opposite of P new meaning meaningful I +can think of no nicer way of ending the + + align:start position:0% +can think of no nicer way of ending the + + + align:start position:0% +can think of no nicer way of ending the +course than by picking as an application + + align:start position:0% +course than by picking as an application + + + align:start position:0% +course than by picking as an application +a topic that + + align:start position:0% +a topic that + + + align:start position:0% +a topic that +existed long before the so-called new + + align:start position:0% +existed long before the so-called new + + + align:start position:0% +existed long before the so-called new +math was born and which exists an in an + + align:start position:0% +math was born and which exists an in an + + + align:start position:0% +math was born and which exists an in an +even more enlightened way in the spirit + + align:start position:0% +even more enlightened way in the spirit + + + align:start position:0% +even more enlightened way in the spirit +of the new mathematics and the topic + + align:start position:0% +of the new mathematics and the topic + + + align:start position:0% +of the new mathematics and the topic +that I have in mind to conclude with and + + align:start position:0% +that I have in mind to conclude with and + + + align:start position:0% +that I have in mind to conclude with and +it also ties in with our lecture of last + + align:start position:0% +it also ties in with our lecture of last + + + align:start position:0% +it also ties in with our lecture of last +time on the dot product is the subject + + align:start position:0% +time on the dot product is the subject + + + align:start position:0% +time on the dot product is the subject +called orthogonal functions which has as + + align:start position:0% +called orthogonal functions which has as + + + align:start position:0% +called orthogonal functions which has as +a special subtopic Fier + + align:start position:0% +a special subtopic Fier + + + align:start position:0% +a special subtopic Fier +series now the way this comes about + + align:start position:0% +series now the way this comes about + + + align:start position:0% +series now the way this comes about +is the following and you you have to + + align:start position:0% +is the following and you you have to + + + align:start position:0% +is the following and you you have to +know nothing about Vector spaces to + + align:start position:0% +know nothing about Vector spaces to + + + align:start position:0% +know nothing about Vector spaces to +appreciate what we're going to do now + + align:start position:0% +appreciate what we're going to do now + + + align:start position:0% +appreciate what we're going to do now +that in a sense we imitate what Fier + + align:start position:0% +that in a sense we imitate what Fier + + + align:start position:0% +that in a sense we imitate what Fier +actually did in trying to solve a + + align:start position:0% +actually did in trying to solve a + + + align:start position:0% +actually did in trying to solve a +particular type of problem we suppose + + align:start position:0% +particular type of problem we suppose + + + align:start position:0% +particular type of problem we suppose +that we have an infinite sequence of + + align:start position:0% +that we have an infinite sequence of + + + align:start position:0% +that we have an infinite sequence of +functions which I'll denote by the + + align:start position:0% +functions which I'll denote by the + + + align:start position:0% +functions which I'll denote by the +family F subn ofx and a particular + + align:start position:0% +family F subn ofx and a particular + + + align:start position:0% +family F subn ofx and a particular +closed interval from A to B such that + + align:start position:0% +closed interval from A to B such that + + + align:start position:0% +closed interval from A to B such that +each member of my family f benx is + + align:start position:0% +each member of my family f benx is + + + align:start position:0% +each member of my family f benx is +integral on the interval from A to B and + + align:start position:0% +integral on the interval from A to B and + + + align:start position:0% +integral on the interval from A to B and +we ALS Al assume that the integral from + + align:start position:0% +we ALS Al assume that the integral from + + + align:start position:0% +we ALS Al assume that the integral from +A to B of the product of any two of + + align:start position:0% +A to B of the product of any two of + + + align:start position:0% +A to B of the product of any two of +these functions two different members of + + align:start position:0% +these functions two different members of + + + align:start position:0% +these functions two different members of +this set that that integral is zero in + + align:start position:0% +this set that that integral is zero in + + + align:start position:0% +this set that that integral is zero in +other words the integral from A to B V + + align:start position:0% +other words the integral from A to B V + + + align:start position:0% +other words the integral from A to B V +sub I ofx * V subj ofx DX is zero + + align:start position:0% +sub I ofx * V subj ofx DX is zero + + + align:start position:0% +sub I ofx * V subj ofx DX is zero +provided I is unequal to J okay so we're + + align:start position:0% +provided I is unequal to J okay so we're + + + align:start position:0% +provided I is unequal to J okay so we're +assuming this particular property + + align:start position:0% +assuming this particular property + + + align:start position:0% +assuming this particular property +remembering of course that the product + + align:start position:0% +remembering of course that the product + + + align:start position:0% +remembering of course that the product +of two integraal functions is again + + align:start position:0% +of two integraal functions is again + + + align:start position:0% +of two integraal functions is again +integrable so that this thing makes + + align:start position:0% +integrable so that this thing makes + + + align:start position:0% +integrable so that this thing makes +sense now traditionally + + align:start position:0% +sense now traditionally + + + align:start position:0% +sense now traditionally +when a family of functions had this + + align:start position:0% +when a family of functions had this + + + align:start position:0% +when a family of functions had this +particular property that family was said + + align:start position:0% +particular property that family was said + + + align:start position:0% +particular property that family was said +to be + + align:start position:0% +to be + + + align:start position:0% +to be +orthogonal on the interval from A to B + + align:start position:0% +orthogonal on the interval from A to B + + + align:start position:0% +orthogonal on the interval from A to B +and I will leave it for a little bit + + align:start position:0% +and I will leave it for a little bit + + + align:start position:0% +and I will leave it for a little bit +later to show you how this jibes with + + align:start position:0% +later to show you how this jibes with + + + align:start position:0% +later to show you how this jibes with +the meaning of orthogonal as we defined + + align:start position:0% +the meaning of orthogonal as we defined + + + align:start position:0% +the meaning of orthogonal as we defined +it in terms of dot products last time + + align:start position:0% +it in terms of dot products last time + + + align:start position:0% +it in terms of dot products last time +but let me show you how for example Fier + + align:start position:0% +but let me show you how for example Fier + + + align:start position:0% +but let me show you how for example Fier +decided to use this type of information + + align:start position:0% +decided to use this type of information + + + align:start position:0% +decided to use this type of information +suppose we had a given function f ofx + + align:start position:0% +suppose we had a given function f ofx + + + align:start position:0% +suppose we had a given function f ofx +that also happened to be integrable on + + align:start position:0% +that also happened to be integrable on + + + align:start position:0% +that also happened to be integrable on +the interval from A to B or written more + + align:start position:0% +the interval from A to B or written more + + + align:start position:0% +the interval from A to B or written more +succinctly we assume that the integral + + align:start position:0% +succinctly we assume that the integral + + + align:start position:0% +succinctly we assume that the integral +from A to B F ofx DX exists let's also + + align:start position:0% +from A to B F ofx DX exists let's also + + + align:start position:0% +from A to B F ofx DX exists let's also +suppose that F ofx happens to be a + + align:start position:0% +suppose that F ofx happens to be a + + + align:start position:0% +suppose that F ofx happens to be a +linear combination of the members of the + + align:start position:0% +linear combination of the members of the + + + align:start position:0% +linear combination of the members of the +orthogonal family Fe sub Ben effect + + align:start position:0% +orthogonal family Fe sub Ben effect + + + align:start position:0% +orthogonal family Fe sub Ben effect +effects in other words that for the + + align:start position:0% +effects in other words that for the + + + align:start position:0% +effects in other words that for the +given orthogonal family f ofx is + + align:start position:0% +given orthogonal family f ofx is + + + align:start position:0% +given orthogonal family f ofx is +summation CN FN of X as n goes from one + + align:start position:0% +summation CN FN of X as n goes from one + + + align:start position:0% +summation CN FN of X as n goes from one +to infinity and the question is + + align:start position:0% +to infinity and the question is + + + align:start position:0% +to infinity and the question is +under or with the knowledge that this is + + align:start position:0% +under or with the knowledge that this is + + + align:start position:0% +under or with the knowledge that this is +an orthogonal family how can we + + align:start position:0% +an orthogonal family how can we + + + align:start position:0% +an orthogonal family how can we +determine each coefficient C subn if + + align:start position:0% +determine each coefficient C subn if + + + align:start position:0% +determine each coefficient C subn if +this condition here is to hold or to + + align:start position:0% +this condition here is to hold or to + + + align:start position:0% +this condition here is to hold or to +make this more concrete and and keep it + + align:start position:0% +make this more concrete and and keep it + + + align:start position:0% +make this more concrete and and keep it +as non symbolic as possible let's + + align:start position:0% +as non symbolic as possible let's + + + align:start position:0% +as non symbolic as possible let's +suppose I wanted to figure out here what + + align:start position:0% +suppose I wanted to figure out here what + + + align:start position:0% +suppose I wanted to figure out here what +C sub3 happened to be the trick is this + + align:start position:0% +C sub3 happened to be the trick is this + + + align:start position:0% +C sub3 happened to be the trick is this +I recognize that from this basic + + align:start position:0% +I recognize that from this basic + + + align:start position:0% +I recognize that from this basic +definition If I multiply f sub3 of x by + + align:start position:0% +definition If I multiply f sub3 of x by + + + align:start position:0% +definition If I multiply f sub3 of x by +any other member of this family other + + align:start position:0% +any other member of this family other + + + align:start position:0% +any other member of this family other +than F sub3 itself and integrate from A + + align:start position:0% +than F sub3 itself and integrate from A + + + align:start position:0% +than F sub3 itself and integrate from A +to B that term will be Z + + align:start position:0% +to B that term will be Z + + + align:start position:0% +to B that term will be Z +so what I do is I come back to this + + align:start position:0% +so what I do is I come back to this + + + align:start position:0% +so what I do is I come back to this +relationship and I multiply both sides + + align:start position:0% +relationship and I multiply both sides + + + align:start position:0% +relationship and I multiply both sides +of this equation by F sub3 ofx keeping + + align:start position:0% +of this equation by F sub3 ofx keeping + + + align:start position:0% +of this equation by F sub3 ofx keeping +in mind if I wanted to find C sub K I + + align:start position:0% +in mind if I wanted to find C sub K I + + + align:start position:0% +in mind if I wanted to find C sub K I +would have multiplied both sides by F + + align:start position:0% +would have multiplied both sides by F + + + align:start position:0% +would have multiplied both sides by F +sub K of X I'm just picking k equal 3 + + align:start position:0% +sub K of X I'm just picking k equal 3 + + + align:start position:0% +sub K of X I'm just picking k equal 3 +here I multiply both sides by F sub3 ofx + + align:start position:0% +here I multiply both sides by F sub3 ofx + + + align:start position:0% +here I multiply both sides by F sub3 ofx +and because f sub3 ofx is + + align:start position:0% +and because f sub3 ofx is + + + align:start position:0% +and because f sub3 ofx is +a constant subscript meaning it doesn't + + align:start position:0% +a constant subscript meaning it doesn't + + + align:start position:0% +a constant subscript meaning it doesn't +depend on the summation n which only + + align:start position:0% +depend on the summation n which only + + + align:start position:0% +depend on the summation n which only +affects the subscript here I I can bring + + align:start position:0% +affects the subscript here I I can bring + + + align:start position:0% +affects the subscript here I I can bring +f sub3 of x inside the summation sign + + align:start position:0% +f sub3 of x inside the summation sign + + + align:start position:0% +f sub3 of x inside the summation sign +now the trick is I integrate both sides + + align:start position:0% +now the trick is I integrate both sides + + + align:start position:0% +now the trick is I integrate both sides +of this equality from A to B in other + + align:start position:0% +of this equality from A to B in other + + + align:start position:0% +of this equality from A to B in other +words I put an integral from A to B on + + align:start position:0% +words I put an integral from A to B on + + + align:start position:0% +words I put an integral from A to B on +both sides here augment this with a DX + + align:start position:0% +both sides here augment this with a DX + + + align:start position:0% +both sides here augment this with a DX +and I now know that this is the case my + + align:start position:0% +and I now know that this is the case my + + + align:start position:0% +and I now know that this is the case my +next gimmick if you want to call it that + + align:start position:0% +next gimmick if you want to call it that + + + align:start position:0% +next gimmick if you want to call it that +and if you don't want to call it that + + align:start position:0% +and if you don't want to call it that + + + align:start position:0% +and if you don't want to call it that +you should because it is a gimmick as + + align:start position:0% +you should because it is a gimmick as + + + align:start position:0% +you should because it is a gimmick as +we'll explain in a moment I simply + + align:start position:0% +we'll explain in a moment I simply + + + align:start position:0% +we'll explain in a moment I simply +interchange the order of summation and + + align:start position:0% +interchange the order of summation and + + + align:start position:0% +interchange the order of summation and +integration + + align:start position:0% +integration + + + align:start position:0% +integration +remembering that the integral of a sum + + align:start position:0% +remembering that the integral of a sum + + + align:start position:0% +remembering that the integral of a sum +is the sum of the integrals I + + align:start position:0% +is the sum of the integrals I + + + align:start position:0% +is the sum of the integrals I +interchange this order and I now have + + align:start position:0% +interchange this order and I now have + + + align:start position:0% +interchange this order and I now have +the summation n goes from 1 to Infinity + + align:start position:0% +the summation n goes from 1 to Infinity + + + align:start position:0% +the summation n goes from 1 to Infinity +integral from A to B CN FN of X F3 of X + + align:start position:0% +integral from A to B CN FN of X F3 of X + + + align:start position:0% +integral from A to B CN FN of X F3 of X +DX and now remembering that F sub that + + align:start position:0% +DX and now remembering that F sub that + + + align:start position:0% +DX and now remembering that F sub that +the integral from a to b f subn of x + + align:start position:0% +the integral from a to b f subn of x + + + align:start position:0% +the integral from a to b f subn of x +time V sub3 ofx DX by definition of + + align:start position:0% +time V sub3 ofx DX by definition of + + + align:start position:0% +time V sub3 ofx DX by definition of +orthogonality is zero unless n equals 3 + + align:start position:0% +orthogonality is zero unless n equals 3 + + + align:start position:0% +orthogonality is zero unless n equals 3 +all of these terms drop out except when + + align:start position:0% +all of these terms drop out except when + + + align:start position:0% +all of these terms drop out except when +n equal 3 now what happens here when n + + align:start position:0% +n equal 3 now what happens here when n + + + align:start position:0% +n equal 3 now what happens here when n +equal 3 this term here is C sub3 this is + + align:start position:0% +equal 3 this term here is C sub3 this is + + + align:start position:0% +equal 3 this term here is C sub3 this is +f sub 3^ 2 x DX integrated from A to B + + align:start position:0% +f sub 3^ 2 x DX integrated from A to B + + + align:start position:0% +f sub 3^ 2 x DX integrated from A to B +and all the remaining terms are zero + + align:start position:0% +and all the remaining terms are zero + + + align:start position:0% +and all the remaining terms are zero +because the integrant is zero in other + + align:start position:0% +because the integrant is zero in other + + + align:start position:0% +because the integrant is zero in other +words the right hand side simply becomes + + align:start position:0% +words the right hand side simply becomes + + + align:start position:0% +words the right hand side simply becomes +well since C3 is a constant I can take + + align:start position:0% +well since C3 is a constant I can take + + + align:start position:0% +well since C3 is a constant I can take +it outside the integral sign it's C3 + + align:start position:0% +it outside the integral sign it's C3 + + + align:start position:0% +it outside the integral sign it's C3 +integral from a Tob F sub 3^ 2 of X DX + + align:start position:0% +integral from a Tob F sub 3^ 2 of X DX + + + align:start position:0% +integral from a Tob F sub 3^ 2 of X DX +and now you see from this relationship + + align:start position:0% +and now you see from this relationship + + + align:start position:0% +and now you see from this relationship +ship here I can solve for C sub3 namely + + align:start position:0% +ship here I can solve for C sub3 namely + + + align:start position:0% +ship here I can solve for C sub3 namely +I simply divide both sides of this + + align:start position:0% +I simply divide both sides of this + + + align:start position:0% +I simply divide both sides of this +equation by this number here now what I + + align:start position:0% +equation by this number here now what I + + + align:start position:0% +equation by this number here now what I +said by gimmick is simply this when we + + align:start position:0% +said by gimmick is simply this when we + + + align:start position:0% +said by gimmick is simply this when we +said that the integral of a sum is a sum + + align:start position:0% +said that the integral of a sum is a sum + + + align:start position:0% +said that the integral of a sum is a sum +of the integrals that was only for a + + align:start position:0% +of the integrals that was only for a + + + align:start position:0% +of the integrals that was only for a +finite sum you may remember in part one + + align:start position:0% +finite sum you may remember in part one + + + align:start position:0% +finite sum you may remember in part one +of our course when we talked about + + align:start position:0% +of our course when we talked about + + + align:start position:0% +of our course when we talked about +uniform convergence one of the things + + align:start position:0% +uniform convergence one of the things + + + align:start position:0% +uniform convergence one of the things +that we pointed out was that for + + align:start position:0% +that we pointed out was that for + + + align:start position:0% +that we pointed out was that for +infinite sums you weren't always + + align:start position:0% +infinite sums you weren't always + + + align:start position:0% +infinite sums you weren't always +guaranteed that you could interchange + + align:start position:0% +guaranteed that you could interchange + + + align:start position:0% +guaranteed that you could interchange +the order of summation and integration + + align:start position:0% +the order of summation and integration + + + align:start position:0% +the order of summation and integration +or as I usually put it you could always + + align:start position:0% +or as I usually put it you could always + + + align:start position:0% +or as I usually put it you could always +interchange them but you may not get the + + align:start position:0% +interchange them but you may not get the + + + align:start position:0% +interchange them but you may not get the +same answer so the first question that + + align:start position:0% +same answer so the first question that + + + align:start position:0% +same answer so the first question that +comes up is how do I know that I am + + align:start position:0% +comes up is how do I know that I am + + + align:start position:0% +comes up is how do I know that I am +allowed to Interchange this order by the + + align:start position:0% +allowed to Interchange this order by the + + + align:start position:0% +allowed to Interchange this order by the +way the second question that comes up is + + align:start position:0% +way the second question that comes up is + + + align:start position:0% +way the second question that comes up is +and this is a more subtle question but + + align:start position:0% +and this is a more subtle question but + + + align:start position:0% +and this is a more subtle question but +going back to what we were talking about + + align:start position:0% +going back to what we were talking about + + + align:start position:0% +going back to what we were talking about +before how do I even know that there is + + align:start position:0% +before how do I even know that there is + + + align:start position:0% +before how do I even know that there is +a linear combination of the fens that + + align:start position:0% +a linear combination of the fens that + + + align:start position:0% +a linear combination of the fens that +comes out to be the given F ofx you see + + align:start position:0% +comes out to be the given F ofx you see + + + align:start position:0% +comes out to be the given F ofx you see +notice that demonstration here + + align:start position:0% +notice that demonstration here + + + align:start position:0% +notice that demonstration here +presupposes that F ofx can be written + + align:start position:0% +presupposes that F ofx can be written + + + align:start position:0% +presupposes that F ofx can be written +this way you see the two questions that + + align:start position:0% +this way you see the two questions that + + + align:start position:0% +this way you see the two questions that +come up is given an F ofx first of all + + align:start position:0% +come up is given an F ofx first of all + + + align:start position:0% +come up is given an F ofx first of all +can it be written this way and secondly + + align:start position:0% +can it be written this way and secondly + + + align:start position:0% +can it be written this way and secondly +even if it can do we have the right to + + align:start position:0% +even if it can do we have the right to + + + align:start position:0% +even if it can do we have the right to +Interchange the order of integration and + + align:start position:0% +Interchange the order of integration and + + + align:start position:0% +Interchange the order of integration and +summation by the way assuming for the + + align:start position:0% +summation by the way assuming for the + + + align:start position:0% +summation by the way assuming for the +moment that we can do this mechanically + + align:start position:0% +moment that we can do this mechanically + + + align:start position:0% +moment that we can do this mechanically +at least notice that what C3 turns out + + align:start position:0% +at least notice that what C3 turns out + + + align:start position:0% +at least notice that what C3 turns out +to be is the integral from a to b f ofx + + align:start position:0% +to be is the integral from a to b f ofx + + + align:start position:0% +to be is the integral from a to b f ofx +f sub3 ofx DX divided by the integral + + align:start position:0% +f sub3 ofx DX divided by the integral + + + align:start position:0% +f sub3 ofx DX divided by the integral +from a to be F sub3 of x^2 * DX and + + align:start position:0% +from a to be F sub3 of x^2 * DX and + + + align:start position:0% +from a to be F sub3 of x^2 * DX and +again replacing the 3 by a k this is how + + align:start position:0% +again replacing the 3 by a k this is how + + + align:start position:0% +again replacing the 3 by a k this is how +every one of these coefficients could + + align:start position:0% +every one of these coefficients could + + + align:start position:0% +every one of these coefficients could +have been determined and now you see as + + align:start position:0% +have been determined and now you see as + + + align:start position:0% +have been determined and now you see as +a very very brief aside which I will go + + align:start position:0% +a very very brief aside which I will go + + + align:start position:0% +a very very brief aside which I will go +into much more detail in the study guide + + align:start position:0% +into much more detail in the study guide + + + align:start position:0% +into much more detail in the study guide +when we talk about the exercises and the + + align:start position:0% +when we talk about the exercises and the + + + align:start position:0% +when we talk about the exercises and the +various discussion of the + + align:start position:0% +various discussion of the + + + align:start position:0% +various discussion of the +exercises given a series of functions + + align:start position:0% +exercises given a series of functions + + + align:start position:0% +exercises given a series of functions +which is integrable on a a sequence of + + align:start position:0% +which is integrable on a a sequence of + + + align:start position:0% +which is integrable on a a sequence of +functions integ bable on a given + + align:start position:0% +functions integ bable on a given + + + align:start position:0% +functions integ bable on a given +interval from A to B one usually def + + align:start position:0% +interval from A to B one usually def + + + align:start position:0% +interval from A to B one usually def +finds the dotproduct of these two + + align:start position:0% +finds the dotproduct of these two + + + align:start position:0% +finds the dotproduct of these two +functions to be the integral from A to B + + align:start position:0% +functions to be the integral from A to B + + + align:start position:0% +functions to be the integral from A to B +the product of the two functions times + + align:start position:0% +the product of the two functions times + + + align:start position:0% +the product of the two functions times +DX you see remember last time we showed + + align:start position:0% +DX you see remember last time we showed + + + align:start position:0% +DX you see remember last time we showed +that all you needed to have a DOT + + align:start position:0% +that all you needed to have a DOT + + + align:start position:0% +that all you needed to have a DOT +product was a rule that showed you how + + align:start position:0% +product was a rule that showed you how + + + align:start position:0% +product was a rule that showed you how +to combine two members of your set to + + align:start position:0% +to combine two members of your set to + + + align:start position:0% +to combine two members of your set to +give you a number and certainly this + + align:start position:0% +give you a number and certainly this + + + align:start position:0% +give you a number and certainly this +thing here is a number and it also had + + align:start position:0% +thing here is a number and it also had + + + align:start position:0% +thing here is a number and it also had +to have three or four basic properties + + align:start position:0% +to have three or four basic properties + + + align:start position:0% +to have three or four basic properties +and as one of the exercises we will show + + align:start position:0% +and as one of the exercises we will show + + + align:start position:0% +and as one of the exercises we will show +that those properties for a DOT product + + align:start position:0% +that those properties for a DOT product + + + align:start position:0% +that those properties for a DOT product +are obeyed here but this is where the + + align:start position:0% +are obeyed here but this is where the + + + align:start position:0% +are obeyed here but this is where the +word orthogonal functions come from + + align:start position:0% +word orthogonal functions come from + + + align:start position:0% +word orthogonal functions come from +notice that in terms of this definition + + align:start position:0% +notice that in terms of this definition + + + align:start position:0% +notice that in terms of this definition +of a DOT product two vectors are + + align:start position:0% +of a DOT product two vectors are + + + align:start position:0% +of a DOT product two vectors are +orthogonal if their dot product is zero + + align:start position:0% +orthogonal if their dot product is zero + + + align:start position:0% +orthogonal if their dot product is zero +and notice saying that this equals zero + + align:start position:0% +and notice saying that this equals zero + + + align:start position:0% +and notice saying that this equals zero +is the same as saying that this integral + + align:start position:0% +is the same as saying that this integral + + + align:start position:0% +is the same as saying that this integral +is zero and that's precisely what the + + align:start position:0% +is zero and that's precisely what the + + + align:start position:0% +is zero and that's precisely what the +definition of orthogonal was so you see + + align:start position:0% +definition of orthogonal was so you see + + + align:start position:0% +definition of orthogonal was so you see +this is the connection between the + + align:start position:0% +this is the connection between the + + + align:start position:0% +this is the connection between the +vector space interpretation of + + align:start position:0% +vector space interpretation of + + + align:start position:0% +vector space interpretation of +orthogonal and the traditional uh + + align:start position:0% +orthogonal and the traditional uh + + + align:start position:0% +orthogonal and the traditional uh +interpretation of orthogonal and as I + + align:start position:0% +interpretation of orthogonal and as I + + + align:start position:0% +interpretation of orthogonal and as I +say I'll leave further discussion of + + align:start position:0% +say I'll leave further discussion of + + + align:start position:0% +say I'll leave further discussion of +that for the the notes but the important + + align:start position:0% +that for the the notes but the important + + + align:start position:0% +that for the the notes but the important +point is this if I mechanically solve + + align:start position:0% +point is this if I mechanically solve + + + align:start position:0% +point is this if I mechanically solve +for these coefficients in other words + + align:start position:0% +for these coefficients in other words + + + align:start position:0% +for these coefficients in other words +suppose I'm given F ofx and without and + + align:start position:0% +suppose I'm given F ofx and without and + + + align:start position:0% +suppose I'm given F ofx and without and +I'm given a family of functions Fe subn + + align:start position:0% +I'm given a family of functions Fe subn + + + align:start position:0% +I'm given a family of functions Fe subn +ofx which is orthogonal on the interval + + align:start position:0% +ofx which is orthogonal on the interval + + + align:start position:0% +ofx which is orthogonal on the interval +from A to B suppose that without even + + align:start position:0% +from A to B suppose that without even + + + align:start position:0% +from A to B suppose that without even +knowing whether F ofx can be represented + + align:start position:0% +knowing whether F ofx can be represented + + + align:start position:0% +knowing whether F ofx can be represented +as a linear combination of the fees and + + align:start position:0% +as a linear combination of the fees and + + + align:start position:0% +as a linear combination of the fees and +that without even knowing whether I can + + align:start position:0% +that without even knowing whether I can + + + align:start position:0% +that without even knowing whether I can +interchange these two operations the + + align:start position:0% +interchange these two operations the + + + align:start position:0% +interchange these two operations the +order in which I perform these two + + align:start position:0% +order in which I perform these two + + + align:start position:0% +order in which I perform these two +operations let's suppose that I + + align:start position:0% +operations let's suppose that I + + + align:start position:0% +operations let's suppose that I +mechanically in + + align:start position:0% +mechanically in + + + align:start position:0% +mechanically in +as my coefficients the C's in this + + align:start position:0% +as my coefficients the C's in this + + + align:start position:0% +as my coefficients the C's in this +particular way in other words regardless + + align:start position:0% +particular way in other words regardless + + + align:start position:0% +particular way in other words regardless +of whether it's it means anything or not + + align:start position:0% +of whether it's it means anything or not + + + align:start position:0% +of whether it's it means anything or not +I can always multiply F ofx by F sub K + + align:start position:0% +I can always multiply F ofx by F sub K + + + align:start position:0% +I can always multiply F ofx by F sub K +of X integrate from A to B you see the + + align:start position:0% +of X integrate from A to B you see the + + + align:start position:0% +of X integrate from A to B you see the +product of two integral functions is + + align:start position:0% +product of two integral functions is + + + align:start position:0% +product of two integral functions is +always integral I can always divide that + + align:start position:0% +always integral I can always divide that + + + align:start position:0% +always integral I can always divide that +by the square of the function f subk of + + align:start position:0% +by the square of the function f subk of + + + align:start position:0% +by the square of the function f subk of +x from A to B keeping in mind by the way + + align:start position:0% +x from A to B keeping in mind by the way + + + align:start position:0% +x from A to B keeping in mind by the way +that as long as f sub3 is not + + align:start position:0% +that as long as f sub3 is not + + + align:start position:0% +that as long as f sub3 is not +identically zero or if it's + + align:start position:0% +identically zero or if it's + + + align:start position:0% +identically zero or if it's +not uh zero other than on a uh set of uh + + align:start position:0% +not uh zero other than on a uh set of uh + + + align:start position:0% +not uh zero other than on a uh set of uh +points of measure zero or what have you + + align:start position:0% +points of measure zero or what have you + + + align:start position:0% +points of measure zero or what have you +notice that the square of a number can't + + align:start position:0% +notice that the square of a number can't + + + align:start position:0% +notice that the square of a number can't +be negative so if f sub3 of x is + + align:start position:0% +be negative so if f sub3 of x is + + + align:start position:0% +be negative so if f sub3 of x is +different from zero in enough places by + + align:start position:0% +different from zero in enough places by + + + align:start position:0% +different from zero in enough places by +squaring it I have a positive integrant + + align:start position:0% +squaring it I have a positive integrant + + + align:start position:0% +squaring it I have a positive integrant +and when I integrate a positive + + align:start position:0% +and when I integrate a positive + + + align:start position:0% +and when I integrate a positive +integrant I can't get zero for an answer + + align:start position:0% +integrant I can't get zero for an answer + + + align:start position:0% +integrant I can't get zero for an answer +so I don't have a zero denominator here + + align:start position:0% +so I don't have a zero denominator here + + + align:start position:0% +so I don't have a zero denominator here +but the point is this if I choose the + + align:start position:0% +but the point is this if I choose the + + + align:start position:0% +but the point is this if I choose the +C's as as I did here see with the C's as + + align:start position:0% +C's as as I did here see with the C's as + + + align:start position:0% +C's as as I did here see with the C's as +just defined we write that F ofx and + + align:start position:0% +just defined we write that F ofx and + + + align:start position:0% +just defined we write that F ofx and +then we put a little squiggle here see + + align:start position:0% +then we put a little squiggle here see + + + align:start position:0% +then we put a little squiggle here see +we don't know if we had the right to + + align:start position:0% +we don't know if we had the right to + + + align:start position:0% +we don't know if we had the right to +assume that this series here is equal to + + align:start position:0% +assume that this series here is equal to + + + align:start position:0% +assume that this series here is equal to +F ofx but we write this little squiggle + + align:start position:0% +F ofx but we write this little squiggle + + + align:start position:0% +F ofx but we write this little squiggle +Mark here we call the resulting infinite + + align:start position:0% +Mark here we call the resulting infinite + + + align:start position:0% +Mark here we call the resulting infinite +series capital F ofx and what we say is + + align:start position:0% +series capital F ofx and what we say is + + + align:start position:0% +series capital F ofx and what we say is +that capital F ofx is the fuer + + align:start position:0% +that capital F ofx is the fuer + + + align:start position:0% +that capital F ofx is the fuer +representation of little f ofx with + + align:start position:0% +representation of little f ofx with + + + align:start position:0% +representation of little f ofx with +respect to the family f subn of x you + + align:start position:0% +respect to the family f subn of x you + + + align:start position:0% +respect to the family f subn of x you +see we don't say that these two are + + align:start position:0% +see we don't say that these two are + + + align:start position:0% +see we don't say that these two are +equal but when we choose these + + align:start position:0% +equal but when we choose these + + + align:start position:0% +equal but when we choose these +coefficients the way I just mentioned + + align:start position:0% +coefficients the way I just mentioned + + + align:start position:0% +coefficients the way I just mentioned +this is in any event called the Fier + + align:start position:0% +this is in any event called the Fier + + + align:start position:0% +this is in any event called the Fier +representation of the function little F + + align:start position:0% +representation of the function little F + + + align:start position:0% +representation of the function little F +ofx now you see there are many questions + + align:start position:0% +ofx now you see there are many questions + + + align:start position:0% +ofx now you see there are many questions +that come up and in the form of an + + align:start position:0% +that come up and in the form of an + + + align:start position:0% +that come up and in the form of an +overview let me just State them first of + + align:start position:0% +overview let me just State them first of + + + align:start position:0% +overview let me just State them first of +all how do we know that capital F ofx is + + align:start position:0% +all how do we know that capital F ofx is + + + align:start position:0% +all how do we know that capital F ofx is +even a convergence series after all this + + align:start position:0% +even a convergence series after all this + + + align:start position:0% +even a convergence series after all this +is an infinite series how do we know it + + align:start position:0% +is an infinite series how do we know it + + + align:start position:0% +is an infinite series how do we know it +even converges secondly if it does + + align:start position:0% +even converges secondly if it does + + + align:start position:0% +even converges secondly if it does +converge how do we know that it + + align:start position:0% +converge how do we know that it + + + align:start position:0% +converge how do we know that it +converges to f ofx the answer is we + + align:start position:0% +converges to f ofx the answer is we + + + align:start position:0% +converges to f ofx the answer is we +don't know we really don't know but + + align:start position:0% +don't know we really don't know but + + + align:start position:0% +don't know we really don't know but +there is a rather remarkable result and + + align:start position:0% +there is a rather remarkable result and + + + align:start position:0% +there is a rather remarkable result and +the result is not that difficult to + + align:start position:0% +the result is not that difficult to + + + align:start position:0% +the result is not that difficult to +prove but in the form of an overview I + + align:start position:0% +prove but in the form of an overview I + + + align:start position:0% +prove but in the form of an overview I +prefer to omit the proof here it will be + + align:start position:0% +prefer to omit the proof here it will be + + + align:start position:0% +prefer to omit the proof here it will be +an exercise in the study guide but I + + align:start position:0% +an exercise in the study guide but I + + + align:start position:0% +an exercise in the study guide but I +think it's important to see what the + + align:start position:0% +think it's important to see what the + + + align:start position:0% +think it's important to see what the +statement of the result is and then we + + align:start position:0% +statement of the result is and then we + + + align:start position:0% +statement of the result is and then we +can talk about the ramifications of that + + align:start position:0% +can talk about the ramifications of that + + + align:start position:0% +can talk about the ramifications of that +but the proof would actually obscure the + + align:start position:0% +but the proof would actually obscure the + + + align:start position:0% +but the proof would actually obscure the +beauty of the result and the aside which + + align:start position:0% +beauty of the result and the aside which + + + align:start position:0% +beauty of the result and the aside which +I leave as an exercise is simply there + + align:start position:0% +I leave as an exercise is simply there + + + align:start position:0% +I leave as an exercise is simply there +this suppose you took a linear + + align:start position:0% +this suppose you took a linear + + + align:start position:0% +this suppose you took a linear +combination of the first n of the terms + + align:start position:0% +combination of the first n of the terms + + + align:start position:0% +combination of the first n of the terms +F1 ofx up to FN + + align:start position:0% +F1 ofx up to FN + + + align:start position:0% +F1 ofx up to FN +ofx okay if you choose the C subk to be + + align:start position:0% +ofx okay if you choose the C subk to be + + + align:start position:0% +ofx okay if you choose the C subk to be +the so-called fuer coefficients the way + + align:start position:0% +the so-called fuer coefficients the way + + + align:start position:0% +the so-called fuer coefficients the way +I just mentioned what is interesting is + + align:start position:0% +I just mentioned what is interesting is + + + align:start position:0% +I just mentioned what is interesting is +this that even if the Fier + + align:start position:0% +this that even if the Fier + + + align:start position:0% +this that even if the Fier +representation doesn't converge to F ofx + + align:start position:0% +representation doesn't converge to F ofx + + + align:start position:0% +representation doesn't converge to F ofx +it has the property that it gives you + + align:start position:0% +it has the property that it gives you + + + align:start position:0% +it has the property that it gives you +the best least square of approximation + + align:start position:0% +the best least square of approximation + + + align:start position:0% +the best least square of approximation +in other words if I were to to compute + + align:start position:0% +in other words if I were to to compute + + + align:start position:0% +in other words if I were to to compute +the difference between F ofx and the sum + + align:start position:0% +the difference between F ofx and the sum + + + align:start position:0% +the difference between F ofx and the sum +of the first n terms in the Fier + + align:start position:0% +of the first n terms in the Fier + + + align:start position:0% +of the first n terms in the Fier +representation where the C's were chosen + + align:start position:0% +representation where the C's were chosen + + + align:start position:0% +representation where the C's were chosen +according to the method I just mentioned + + align:start position:0% +according to the method I just mentioned + + + align:start position:0% +according to the method I just mentioned +to you + + align:start position:0% +to you + + + align:start position:0% +to you +before and square that difference you + + align:start position:0% +before and square that difference you + + + align:start position:0% +before and square that difference you +see this is why it's called the mean + + align:start position:0% +see this is why it's called the mean + + + align:start position:0% +see this is why it's called the mean +Square idea you see large errors and + + align:start position:0% +Square idea you see large errors and + + + align:start position:0% +Square idea you see large errors and +small number errors in other words a + + align:start position:0% +small number errors in other words a + + + align:start position:0% +small number errors in other words a +large negative error can cancel a large + + align:start position:0% +large negative error can cancel a large + + + align:start position:0% +large negative error can cancel a large +positive error because the algebraic + + align:start position:0% +positive error because the algebraic + + + align:start position:0% +positive error because the algebraic +signs tend to cancel one another but by + + align:start position:0% +signs tend to cancel one another but by + + + align:start position:0% +signs tend to cancel one another but by +squaring large errors all of these + + align:start position:0% +squaring large errors all of these + + + align:start position:0% +squaring large errors all of these +become what squares of large magnitudes + + align:start position:0% +become what squares of large magnitudes + + + align:start position:0% +become what squares of large magnitudes +are large positive magnitudes by + + align:start position:0% +are large positive magnitudes by + + + align:start position:0% +are large positive magnitudes by +squaring I really magnify the errors the + + align:start position:0% +squaring I really magnify the errors the + + + align:start position:0% +squaring I really magnify the errors the +positives can't cancel the negatives and + + align:start position:0% +positives can't cancel the negatives and + + + align:start position:0% +positives can't cancel the negatives and +what this says is that if I use this + + align:start position:0% +what this says is that if I use this + + + align:start position:0% +what this says is that if I use this +linear combination of the Fe sub NS that + + align:start position:0% +linear combination of the Fe sub NS that + + + align:start position:0% +linear combination of the Fe sub NS that +the least Square approximate the square + + align:start position:0% +the least Square approximate the square + + + align:start position:0% +the least Square approximate the square +approximation error is less using the + + align:start position:0% +approximation error is less using the + + + align:start position:0% +approximation error is less using the +these coefficients than if I had used + + align:start position:0% +these coefficients than if I had used + + + align:start position:0% +these coefficients than if I had used +any other possible coefficients that if + + align:start position:0% +any other possible coefficients that if + + + align:start position:0% +any other possible coefficients that if +I picked any other coefficients in the + + align:start position:0% +I picked any other coefficients in the + + + align:start position:0% +I picked any other coefficients in the +whole world other than the ones that I + + align:start position:0% +whole world other than the ones that I + + + align:start position:0% +whole world other than the ones that I +found by the method indicat just a + + align:start position:0% +found by the method indicat just a + + + align:start position:0% +found by the method indicat just a +little while ago if I summed these terms + + align:start position:0% +little while ago if I summed these terms + + + align:start position:0% +little while ago if I summed these terms +subtracted that from F ofx squared and + + align:start position:0% +subtracted that from F ofx squared and + + + align:start position:0% +subtracted that from F ofx squared and +integrated the result from A to B I + + align:start position:0% +integrated the result from A to B I + + + align:start position:0% +integrated the result from A to B I +would get a number which was at least as + + align:start position:0% +would get a number which was at least as + + + align:start position:0% +would get a number which was at least as +large and in most cases in fact unless + + align:start position:0% +large and in most cases in fact unless + + + align:start position:0% +large and in most cases in fact unless +the D subk were chosen to equal the C + + align:start position:0% +the D subk were chosen to equal the C + + + align:start position:0% +the D subk were chosen to equal the C +subk I would get a number which was + + align:start position:0% +subk I would get a number which was + + + align:start position:0% +subk I would get a number which was +larger than this now you see what this + + align:start position:0% +larger than this now you see what this + + + align:start position:0% +larger than this now you see what this +thing says what this says is that there + + align:start position:0% +thing says what this says is that there + + + align:start position:0% +thing says what this says is that there +can't be any real interval where this + + align:start position:0% +can't be any real interval where this + + + align:start position:0% +can't be any real interval where this +gets very very far away from F ofx + + align:start position:0% +gets very very far away from F ofx + + + align:start position:0% +gets very very far away from F ofx +because you see if it did if it did get + + align:start position:0% +because you see if it did if it did get + + + align:start position:0% +because you see if it did if it did get +very very far away this would be a large + + align:start position:0% +very very far away this would be a large + + + align:start position:0% +very very far away this would be a large +magnitude squaring it would give me a + + align:start position:0% +magnitude squaring it would give me a + + + align:start position:0% +magnitude squaring it would give me a +positive large magnitude integrating + + align:start position:0% +positive large magnitude integrating + + + align:start position:0% +positive large magnitude integrating +that from A to B would make this thing + + align:start position:0% +that from A to B would make this thing + + + align:start position:0% +that from A to B would make this thing +still very very large and why should it + + align:start position:0% +still very very large and why should it + + + align:start position:0% +still very very large and why should it +stay smaller than any other linear + + align:start position:0% +stay smaller than any other linear + + + align:start position:0% +stay smaller than any other linear +combination I can get + + align:start position:0% +combination I can get + + + align:start position:0% +combination I can get +and I'll emphasize this more from a + + align:start position:0% +and I'll emphasize this more from a + + + align:start position:0% +and I'll emphasize this more from a +concrete point of view in a few moments + + align:start position:0% +concrete point of view in a few moments + + + align:start position:0% +concrete point of view in a few moments +but for the time being what the impact + + align:start position:0% +but for the time being what the impact + + + align:start position:0% +but for the time being what the impact +of this beautiful result is and notice + + align:start position:0% +of this beautiful result is and notice + + + align:start position:0% +of this beautiful result is and notice +it doesn't look like much when you look + + align:start position:0% +it doesn't look like much when you look + + + align:start position:0% +it doesn't look like much when you look +at it like this it just looks like some + + align:start position:0% +at it like this it just looks like some + + + align:start position:0% +at it like this it just looks like some +abstract remark but the beauty of this + + align:start position:0% +abstract remark but the beauty of this + + + align:start position:0% +abstract remark but the beauty of this +remark the impact of it is that when you + + align:start position:0% +remark the impact of it is that when you + + + align:start position:0% +remark the impact of it is that when you +write the so-called Fier representation + + align:start position:0% +write the so-called Fier representation + + + align:start position:0% +write the so-called Fier representation +as opposed to power series which I'll + + align:start position:0% +as opposed to power series which I'll + + + align:start position:0% +as opposed to power series which I'll +also mention at the end of the lecture + + align:start position:0% +also mention at the end of the lecture + + + align:start position:0% +also mention at the end of the lecture +what the contrast really is the + + align:start position:0% +what the contrast really is the + + + align:start position:0% +what the contrast really is the +fura representation if it does converge + + align:start position:0% +fura representation if it does converge + + + align:start position:0% +fura representation if it does converge +at all converges to the function what we + + align:start position:0% +at all converges to the function what we + + + align:start position:0% +at all converges to the function what we +call in the lodge that over the whole + + align:start position:0% +call in the lodge that over the whole + + + align:start position:0% +call in the lodge that over the whole +interval it starts to fit the function + + align:start position:0% +interval it starts to fit the function + + + align:start position:0% +interval it starts to fit the function +very nicely now I'll come back to that + + align:start position:0% +very nicely now I'll come back to that + + + align:start position:0% +very nicely now I'll come back to that +in terms of a more specific example in a + + align:start position:0% +in terms of a more specific example in a + + + align:start position:0% +in terms of a more specific example in a +few moments let me point out that fora + + align:start position:0% +few moments let me point out that fora + + + align:start position:0% +few moments let me point out that fora +being basically an engineer and a + + align:start position:0% +being basically an engineer and a + + + align:start position:0% +being basically an engineer and a +scientist work with one particular set + + align:start position:0% +scientist work with one particular set + + + align:start position:0% +scientist work with one particular set +of orthogonal + + align:start position:0% +of orthogonal + + + align:start position:0% +of orthogonal +functions a set of orthogonal functions + + align:start position:0% +functions a set of orthogonal functions + + + align:start position:0% +functions a set of orthogonal functions +that were very very natural to anybody + + align:start position:0% +that were very very natural to anybody + + + align:start position:0% +that were very very natural to anybody +working with wave motion or uh things of + + align:start position:0% +working with wave motion or uh things of + + + align:start position:0% +working with wave motion or uh things of +this type as you'll see in a moment the + + align:start position:0% +this type as you'll see in a moment the + + + align:start position:0% +this type as you'll see in a moment the +special case that I have in mind is this + + align:start position:0% +special case that I have in mind is this + + + align:start position:0% +special case that I have in mind is this +consider the family of functions well I + + align:start position:0% +consider the family of functions well I + + + align:start position:0% +consider the family of functions well I +can call this cosine 0x which is just + + align:start position:0% +can call this cosine 0x which is just + + + align:start position:0% +can call this cosine 0x which is just +another way of writing one but I have 1 + + align:start position:0% +another way of writing one but I have 1 + + + align:start position:0% +another way of writing one but I have 1 +cosine x cosine 2X cosine 3x cosine 4X + + align:start position:0% +cosine x cosine 2X cosine 3x cosine 4X + + + align:start position:0% +cosine x cosine 2X cosine 3x cosine 4X +Etc and also included in this family + + align:start position:0% +Etc and also included in this family + + + align:start position:0% +Etc and also included in this family +sinx sin 2x sin 3x Etc I claim that this + + align:start position:0% +sinx sin 2x sin 3x Etc I claim that this + + + align:start position:0% +sinx sin 2x sin 3x Etc I claim that this +family of functions is orthogonal on the + + align:start position:0% +family of functions is orthogonal on the + + + align:start position:0% +family of functions is orthogonal on the +interval from PI to Pi + + align:start position:0% +interval from PI to Pi + + + align:start position:0% +interval from PI to Pi +what I mean by that is what that if I + + align:start position:0% +what I mean by that is what that if I + + + align:start position:0% +what I mean by that is what that if I +take any two different members of this + + align:start position:0% +take any two different members of this + + + align:start position:0% +take any two different members of this +family multiply them together integrate + + align:start position:0% +family multiply them together integrate + + + align:start position:0% +family multiply them together integrate +from minus pi to Pi the result will + + align:start position:0% +from minus pi to Pi the result will + + + align:start position:0% +from minus pi to Pi the result will +always be zero now the I won't go + + align:start position:0% +always be zero now the I won't go + + + align:start position:0% +always be zero now the I won't go +through this whole thing that will also + + align:start position:0% +through this whole thing that will also + + + align:start position:0% +through this whole thing that will also +be one of the exercises in the study + + align:start position:0% +be one of the exercises in the study + + + align:start position:0% +be one of the exercises in the study +guide would be to verify this but let me + + align:start position:0% +guide would be to verify this but let me + + + align:start position:0% +guide would be to verify this but let me +give you a head start in doing this let + + align:start position:0% +give you a head start in doing this let + + + align:start position:0% +give you a head start in doing this let +me pick two members of the coine two + + align:start position:0% +me pick two members of the coine two + + + align:start position:0% +me pick two members of the coine two +different members of the cosine family + + align:start position:0% +different members of the cosine family + + + align:start position:0% +different members of the cosine family +here and multiply them together and + + align:start position:0% +here and multiply them together and + + + align:start position:0% +here and multiply them together and +integrate from minus pi to Pi in other + + align:start position:0% +integrate from minus pi to Pi in other + + + align:start position:0% +integrate from minus pi to Pi in other +words let me take integral fromus piun + + align:start position:0% +words let me take integral fromus piun + + + align:start position:0% +words let me take integral fromus piun +to Pi cosine MX cosine NX DX where m is + + align:start position:0% +to Pi cosine MX cosine NX DX where m is + + + align:start position:0% +to Pi cosine MX cosine NX DX where m is +unequal to n now again without + + align:start position:0% +unequal to n now again without + + + align:start position:0% +unequal to n now again without +belaboring this point remember that the + + align:start position:0% +belaboring this point remember that the + + + align:start position:0% +belaboring this point remember that the +formula for cosine a cosine B comes from + + align:start position:0% +formula for cosine a cosine B comes from + + + align:start position:0% +formula for cosine a cosine B comes from +looking at the formulas for cosine a + + align:start position:0% +looking at the formulas for cosine a + + + align:start position:0% +looking at the formulas for cosine a +plus b cosine of a minus B and adding + + align:start position:0% +plus b cosine of a minus B and adding + + + align:start position:0% +plus b cosine of a minus B and adding +these two results and the sin a sin B + + align:start position:0% +these two results and the sin a sin B + + + align:start position:0% +these two results and the sin a sin B +terms drop out to make a long story + + align:start position:0% +terms drop out to make a long story + + + align:start position:0% +terms drop out to make a long story +short or somewhat shorter cosine MX * + + align:start position:0% +short or somewhat shorter cosine MX * + + + align:start position:0% +short or somewhat shorter cosine MX * +cosine NX is another way of writing 12 + + align:start position:0% +cosine NX is another way of writing 12 + + + align:start position:0% +cosine NX is another way of writing 12 +the sum of cosine m + NX plus cosine M + + align:start position:0% +the sum of cosine m + NX plus cosine M + + + align:start position:0% +the sum of cosine m + NX plus cosine M +minus n x now you see to integrate this + + align:start position:0% +minus n x now you see to integrate this + + + align:start position:0% +minus n x now you see to integrate this +very simply this just gives me what a + + align:start position:0% +very simply this just gives me what a + + + align:start position:0% +very simply this just gives me what a +1/2 here this is sin m + NX over m + n + + align:start position:0% +1/2 here this is sin m + NX over m + n + + + align:start position:0% +1/2 here this is sin m + NX over m + n +this is sin m- x m minus n * X over M + + align:start position:0% +this is sin m- x m minus n * X over M + + + align:start position:0% +this is sin m- x m minus n * X over M +minus n and notice by the way the fact + + align:start position:0% +minus n and notice by the way the fact + + + align:start position:0% +minus n and notice by the way the fact +that m is une equal to n guarantees me + + align:start position:0% +that m is une equal to n guarantees me + + + align:start position:0% +that m is une equal to n guarantees me +my denominator here can't be zero and at + + align:start position:0% +my denominator here can't be zero and at + + + align:start position:0% +my denominator here can't be zero and at +any rate noticing that when I evaluate + + align:start position:0% +any rate noticing that when I evaluate + + + align:start position:0% +any rate noticing that when I evaluate +this from xal minus pi to Pi that these + + align:start position:0% +this from xal minus pi to Pi that these + + + align:start position:0% +this from xal minus pi to Pi that these +are + + align:start position:0% +are + + + align:start position:0% +are +integral integral meaning whole number + + align:start position:0% +integral integral meaning whole number + + + align:start position:0% +integral integral meaning whole number +multiples of Pi both these terms are + + align:start position:0% +multiples of Pi both these terms are + + + align:start position:0% +multiples of Pi both these terms are +zero and we've established the fact that + + align:start position:0% +zero and we've established the fact that + + + align:start position:0% +zero and we've established the fact that +this is zero so at least the members of + + align:start position:0% +this is zero so at least the members of + + + align:start position:0% +this is zero so at least the members of +the cosine family are orthogonal one can + + align:start position:0% +the cosine family are orthogonal one can + + + align:start position:0% +the cosine family are orthogonal one can +also show the members of the sign family + + align:start position:0% +also show the members of the sign family + + + align:start position:0% +also show the members of the sign family +are orthogonal and one can also show + + align:start position:0% +are orthogonal and one can also show + + + align:start position:0% +are orthogonal and one can also show +that any member of the cosine family + + align:start position:0% +that any member of the cosine family + + + align:start position:0% +that any member of the cosine family +taken uh multiplied by any member of the + + align:start position:0% +taken uh multiplied by any member of the + + + align:start position:0% +taken uh multiplied by any member of the +S family integrated from minus pi to Pi + + align:start position:0% +S family integrated from minus pi to Pi + + + align:start position:0% +S family integrated from minus pi to Pi +also gives zero so the point then is + + align:start position:0% +also gives zero so the point then is + + + align:start position:0% +also gives zero so the point then is +that an that this family here is an + + align:start position:0% +that an that this family here is an + + + align:start position:0% +that an that this family here is an +orthogonal F family on the interval from + + align:start position:0% +orthogonal F family on the interval from + + + align:start position:0% +orthogonal F family on the interval from +minus pi to Pi and the beauty of this + + align:start position:0% +minus pi to Pi and the beauty of this + + + align:start position:0% +minus pi to Pi and the beauty of this +result and let me point out that in + + align:start position:0% +result and let me point out that in + + + align:start position:0% +result and let me point out that in +textbooks on advanced mathematics the + + align:start position:0% +textbooks on advanced mathematics the + + + align:start position:0% +textbooks on advanced mathematics the +multitude of pages are used to prove the + + align:start position:0% +multitude of pages are used to prove the + + + align:start position:0% +multitude of pages are used to prove the +results but the state ments that of the + + align:start position:0% +results but the state ments that of the + + + align:start position:0% +results but the state ments that of the +theorems that you prove are not that + + align:start position:0% +theorems that you prove are not that + + + align:start position:0% +theorems that you prove are not that +difficult to keep track of let me just + + align:start position:0% +difficult to keep track of let me just + + + align:start position:0% +difficult to keep track of let me just +give one major result a result that is + + align:start position:0% +give one major result a result that is + + + align:start position:0% +give one major result a result that is +very very crucial and one that I will + + align:start position:0% +very very crucial and one that I will + + + align:start position:0% +very very crucial and one that I will +emphasize in the study guide and that is + + align:start position:0% +emphasize in the study guide and that is + + + align:start position:0% +emphasize in the study guide and that is +this suppose that I'm given a particular + + align:start position:0% +this suppose that I'm given a particular + + + align:start position:0% +this suppose that I'm given a particular +function little F ofx which is peace + + align:start position:0% +function little F ofx which is peace + + + align:start position:0% +function little F ofx which is peace +wise smooth on the interval from minus + + align:start position:0% +wise smooth on the interval from minus + + + align:start position:0% +wise smooth on the interval from minus +pi to Pi and remember what I mean by pie + + align:start position:0% +pi to Pi and remember what I mean by pie + + + align:start position:0% +pi to Pi and remember what I mean by pie +y smooth I mean it's a differentiable + + align:start position:0% +y smooth I mean it's a differentiable + + + align:start position:0% +y smooth I mean it's a differentiable +function except that it may have a + + align:start position:0% +function except that it may have a + + + align:start position:0% +function except that it may have a +finite number of jump discontinuities + + align:start position:0% +finite number of jump discontinuities + + + align:start position:0% +finite number of jump discontinuities +that if I plot the graph yal F ofx I get + + align:start position:0% +that if I plot the graph yal F ofx I get + + + align:start position:0% +that if I plot the graph yal F ofx I get +a smooth curve with the possible + + align:start position:0% +a smooth curve with the possible + + + align:start position:0% +a smooth curve with the possible +exception that there may be a few jumps + + align:start position:0% +exception that there may be a few jumps + + + align:start position:0% +exception that there may be a few jumps +in it by few meaning what a not too + + align:start position:0% +in it by few meaning what a not too + + + align:start position:0% +in it by few meaning what a not too +great infinite number a set of measures + + align:start position:0% +great infinite number a set of measures + + + align:start position:0% +great infinite number a set of measures +zero type thing but we won't be label + + align:start position:0% +zero type thing but we won't be label + + + align:start position:0% +zero type thing but we won't be label +that point right now but the idea is + + align:start position:0% +that point right now but the idea is + + + align:start position:0% +that point right now but the idea is +this suppose that I have this piece y + + align:start position:0% +this suppose that I have this piece y + + + align:start position:0% +this suppose that I have this piece y +smooth function little F ofx and suppose + + align:start position:0% +smooth function little F ofx and suppose + + + align:start position:0% +smooth function little F ofx and suppose +capital F ofx is the Fier representation + + align:start position:0% +capital F ofx is the Fier representation + + + align:start position:0% +capital F ofx is the Fier representation +of little f F ofx relative to my SS and + + align:start position:0% +of little f F ofx relative to my SS and + + + align:start position:0% +of little f F ofx relative to my SS and +cosiness in other words capital F ofx is + + align:start position:0% +cosiness in other words capital F ofx is + + + align:start position:0% +cosiness in other words capital F ofx is +the linear combinations of the cosine + + align:start position:0% +the linear combinations of the cosine + + + align:start position:0% +the linear combinations of the cosine +terms and the sign terms where the + + align:start position:0% +terms and the sign terms where the + + + align:start position:0% +terms and the sign terms where the +coefficients are chosen by that little + + align:start position:0% +coefficients are chosen by that little + + + align:start position:0% +coefficients are chosen by that little +recipe that I showed you at the + + align:start position:0% +recipe that I showed you at the + + + align:start position:0% +recipe that I showed you at the +beginning of the lecture and which as I + + align:start position:0% +beginning of the lecture and which as I + + + align:start position:0% +beginning of the lecture and which as I +say I'll reinforce as we do the + + align:start position:0% +say I'll reinforce as we do the + + + align:start position:0% +say I'll reinforce as we do the +exercises okay at any rate let's call + + align:start position:0% +exercises okay at any rate let's call + + + align:start position:0% +exercises okay at any rate let's call +this capital F ofx and in this + + align:start position:0% +this capital F ofx and in this + + + align:start position:0% +this capital F ofx and in this +particular case another words what + + align:start position:0% +particular case another words what + + + align:start position:0% +particular case another words what +particular case if little f ofx is pie y + + align:start position:0% +particular case if little f ofx is pie y + + + align:start position:0% +particular case if little f ofx is pie y +smooth and the orthogonal function are + + align:start position:0% +smooth and the orthogonal function are + + + align:start position:0% +smooth and the orthogonal function are +the SS and cosin on the interval fromus + + align:start position:0% +the SS and cosin on the interval fromus + + + align:start position:0% +the SS and cosin on the interval fromus +pi to Pi then the Fier representation of + + align:start position:0% +pi to Pi then the Fier representation of + + + align:start position:0% +pi to Pi then the Fier representation of +f ofx capital F ofx is given by the + + align:start position:0% +f ofx capital F ofx is given by the + + + align:start position:0% +f ofx capital F ofx is given by the +following and this is a remarkable + + align:start position:0% +following and this is a remarkable + + + align:start position:0% +following and this is a remarkable +result it says that capital F ofx at any + + align:start position:0% +result it says that capital F ofx at any + + + align:start position:0% +result it says that capital F ofx at any +value of x in the interval from minus pi + + align:start position:0% +value of x in the interval from minus pi + + + align:start position:0% +value of x in the interval from minus pi +to Pi is little F of X+ plus little F of + + align:start position:0% +to Pi is little F of X+ plus little F of + + + align:start position:0% +to Pi is little F of X+ plus little F of +xus over 2 now what does f ofx plus mean + + align:start position:0% +xus over 2 now what does f ofx plus mean + + + align:start position:0% +xus over 2 now what does f ofx plus mean +that means the limit of f ofx as you + + align:start position:0% +that means the limit of f ofx as you + + + align:start position:0% +that means the limit of f ofx as you +approach the given value of x from the + + align:start position:0% +approach the given value of x from the + + + align:start position:0% +approach the given value of x from the +positive side and this F ofx minus is + + align:start position:0% +positive side and this F ofx minus is + + + align:start position:0% +positive side and this F ofx minus is +the limit of f ofx as you approach the + + align:start position:0% +the limit of f ofx as you approach the + + + align:start position:0% +the limit of f ofx as you approach the +given value of x from the negative side + + align:start position:0% +given value of x from the negative side + + + align:start position:0% +given value of x from the negative side +in fact to keep this easier to + + align:start position:0% +in fact to keep this easier to + + + align:start position:0% +in fact to keep this easier to +understand so I don't use x in two + + align:start position:0% +understand so I don't use x in two + + + align:start position:0% +understand so I don't use x in two +different ways what I'm saying is + + align:start position:0% +different ways what I'm saying is + + + align:start position:0% +different ways what I'm saying is +capital F ofx Sub 0 is computed as + + align:start position:0% +capital F ofx Sub 0 is computed as + + + align:start position:0% +capital F ofx Sub 0 is computed as +follows see what little F ofx Sub 0 is + + align:start position:0% +follows see what little F ofx Sub 0 is + + + align:start position:0% +follows see what little F ofx Sub 0 is +as X approaches x0 from the left see + + align:start position:0% +as X approaches x0 from the left see + + + align:start position:0% +as X approaches x0 from the left see +what F of x0 of f of x approaches as X + + align:start position:0% +what F of x0 of f of x approaches as X + + + align:start position:0% +what F of x0 of f of x approaches as X +approaches x0 from the right + + align:start position:0% +approaches x0 from the right + + + align:start position:0% +approaches x0 from the right +Okay add these two results and divide by + + align:start position:0% +Okay add these two results and divide by + + + align:start position:0% +Okay add these two results and divide by +two I hope that you can see that what + + align:start position:0% +two I hope that you can see that what + + + align:start position:0% +two I hope that you can see that what +I'm doing here is taking the average of + + align:start position:0% +I'm doing here is taking the average of + + + align:start position:0% +I'm doing here is taking the average of +these two results half the sum is the + + align:start position:0% +these two results half the sum is the + + + align:start position:0% +these two results half the sum is the +average also observe that if F happens + + align:start position:0% +average also observe that if F happens + + + align:start position:0% +average also observe that if F happens +to be continuous at x0 F of x0 plus is + + align:start position:0% +to be continuous at x0 F of x0 plus is + + + align:start position:0% +to be continuous at x0 F of x0 plus is +the same as F of x0 minus you see the + + align:start position:0% +the same as F of x0 minus you see the + + + align:start position:0% +the same as F of x0 minus you see the +only time that these two things can be + + align:start position:0% +only time that these two things can be + + + align:start position:0% +only time that these two things can be +different is if there's a jump in the + + align:start position:0% +different is if there's a jump in the + + + align:start position:0% +different is if there's a jump in the +function at X Z because if there's no + + align:start position:0% +function at X Z because if there's no + + + align:start position:0% +function at X Z because if there's no +jump as I approach x0 from the left and + + align:start position:0% +jump as I approach x0 from the left and + + + align:start position:0% +jump as I approach x0 from the left and +approach x0 from the right the two + + align:start position:0% +approach x0 from the right the two + + + align:start position:0% +approach x0 from the right the two +values that I get must be the same in + + align:start position:0% +values that I get must be the same in + + + align:start position:0% +values that I get must be the same in +other words notice that at the points + + align:start position:0% +other words notice that at the points + + + align:start position:0% +other words notice that at the points +where f is continuous this is nothing + + align:start position:0% +where f is continuous this is nothing + + + align:start position:0% +where f is continuous this is nothing +more than f ofx z itself and what this + + align:start position:0% +more than f ofx z itself and what this + + + align:start position:0% +more than f ofx z itself and what this +famous result says is that except at the + + align:start position:0% +famous result says is that except at the + + + align:start position:0% +famous result says is that except at the +points at which cap little f ofx are + + align:start position:0% +points at which cap little f ofx are + + + align:start position:0% +points at which cap little f ofx are +disc is discontinuous capital F the fuer + + align:start position:0% +disc is discontinuous capital F the fuer + + + align:start position:0% +disc is discontinuous capital F the fuer +representation is little F at itself + + align:start position:0% +representation is little F at itself + + + align:start position:0% +representation is little F at itself +that the Fier representation converges + + align:start position:0% +that the Fier representation converges + + + align:start position:0% +that the Fier representation converges +to the function itself and what it does + + align:start position:0% +to the function itself and what it does + + + align:start position:0% +to the function itself and what it does +that's remarkable is that where there's + + align:start position:0% +that's remarkable is that where there's + + + align:start position:0% +that's remarkable is that where there's +a jump in the + + align:start position:0% +a jump in the + + + align:start position:0% +a jump in the +function it equals the average of the + + align:start position:0% +function it equals the average of the + + + align:start position:0% +function it equals the average of the +jump well let me show you that in terms + + align:start position:0% +jump well let me show you that in terms + + + align:start position:0% +jump well let me show you that in terms +of an example let me pick a very simple + + align:start position:0% +of an example let me pick a very simple + + + align:start position:0% +of an example let me pick a very simple +function to begin with let me Define the + + align:start position:0% +function to begin with let me Define the + + + align:start position:0% +function to begin with let me Define the +function little F ofx to be negative 1 + + align:start position:0% +function little F ofx to be negative 1 + + + align:start position:0% +function little F ofx to be negative 1 +when X is from when X is in the interval + + align:start position:0% +when X is from when X is in the interval + + + align:start position:0% +when X is from when X is in the interval +from minus pi to 0 and let it be + + align:start position:0% + + + + align:start position:0% + +say positive 1 when X is in the interval + + align:start position:0% +say positive 1 when X is in the interval + + + align:start position:0% +say positive 1 when X is in the interval +from 0 to Pi so graphically you see how + + align:start position:0% +from 0 to Pi so graphically you see how + + + align:start position:0% +from 0 to Pi so graphically you see how +this thing is going to look it goes like + + align:start position:0% + + + + align:start position:0% + +this by the way notice that this is what + + align:start position:0% +this by the way notice that this is what + + + align:start position:0% +this by the way notice that this is what +mathematically we call an odd function + + align:start position:0% +mathematically we call an odd function + + + align:start position:0% +mathematically we call an odd function +right f ofx is the negative of f of + + align:start position:0% +right f ofx is the negative of f of + + + align:start position:0% +right f ofx is the negative of f of +minus X notice that the sign terms are + + align:start position:0% +minus X notice that the sign terms are + + + align:start position:0% +minus X notice that the sign terms are +odd the cosine terms are even you see + + align:start position:0% +odd the cosine terms are even you see + + + align:start position:0% +odd the cosine terms are even you see +cosine of x is the same as cosine of + + align:start position:0% +cosine of x is the same as cosine of + + + align:start position:0% +cosine of x is the same as cosine of +minus X but s of X is minus sin - x so + + align:start position:0% +minus X but s of X is minus sin - x so + + + align:start position:0% +minus X but s of X is minus sin - x so +the S terms are odd the cosine terms are + + align:start position:0% +the S terms are odd the cosine terms are + + + align:start position:0% +the S terms are odd the cosine terms are +even so the first hint or the first nice + + align:start position:0% +even so the first hint or the first nice + + + align:start position:0% +even so the first hint or the first nice +simplification that takes place by + + align:start position:0% +simplification that takes place by + + + align:start position:0% +simplification that takes place by +choosing this example is that because + + align:start position:0% +choosing this example is that because + + + align:start position:0% +choosing this example is that because +this is an odd function the cosine terms + + align:start position:0% +this is an odd function the cosine terms + + + align:start position:0% +this is an odd function the cosine terms +will all be absent that it turns out + + align:start position:0% +will all be absent that it turns out + + + align:start position:0% +will all be absent that it turns out +that if I use the procedure indicated + + align:start position:0% +that if I use the procedure indicated + + + align:start position:0% +that if I use the procedure indicated +earlier in the lecture and again that + + align:start position:0% +earlier in the lecture and again that + + + align:start position:0% +earlier in the lecture and again that +will be one of the exercises so that you + + align:start position:0% +will be one of the exercises so that you + + + align:start position:0% +will be one of the exercises so that you +get the drill that's necessary here + + align:start position:0% +get the drill that's necessary here + + + align:start position:0% +get the drill that's necessary here +again I only want to give you the + + align:start position:0% +again I only want to give you the + + + align:start position:0% +again I only want to give you the +overview it turns out that the forier + + align:start position:0% +overview it turns out that the forier + + + align:start position:0% +overview it turns out that the forier +series representation of this particular + + align:start position:0% +series representation of this particular + + + align:start position:0% +series representation of this particular +function capital F ofx turns out to be 4 + + align:start position:0% +function capital F ofx turns out to be 4 + + + align:start position:0% +function capital F ofx turns out to be 4 +over pi times the summation sin NX Over + + align:start position:0% +over pi times the summation sin NX Over + + + align:start position:0% +over pi times the summation sin NX Over +N for n odd and what that means is it's + + align:start position:0% +N for n odd and what that means is it's + + + align:start position:0% +N for n odd and what that means is it's +4 over Pi time sin x + sin 3x over 3 + + + align:start position:0% +4 over Pi time sin x + sin 3x over 3 + + + + align:start position:0% +4 over Pi time sin x + sin 3x over 3 + +sin 5x over 5 + + align:start position:0% +sin 5x over 5 + + + align:start position:0% +sin 5x over 5 +Etc by the way these are very difficult + + align:start position:0% +Etc by the way these are very difficult + + + align:start position:0% +Etc by the way these are very difficult +things to draw you're not used to + + align:start position:0% +things to draw you're not used to + + + align:start position:0% +things to draw you're not used to +working with these uh I should point out + + align:start position:0% +working with these uh I should point out + + + align:start position:0% +working with these uh I should point out +this that if there's anything that works + + align:start position:0% +this that if there's anything that works + + + align:start position:0% +this that if there's anything that works +nicely in the laboratory It's s and + + align:start position:0% +nicely in the laboratory It's s and + + + align:start position:0% +nicely in the laboratory It's s and +cosine terms because those are things + + align:start position:0% +cosine terms because those are things + + + align:start position:0% +cosine terms because those are things +that you can produce very nicely on an + + align:start position:0% +that you can produce very nicely on an + + + align:start position:0% +that you can produce very nicely on an +oscilloscope analytically these are very + + align:start position:0% +oscilloscope analytically these are very + + + align:start position:0% +oscilloscope analytically these are very +nasty terms to handle but electronically + + align:start position:0% +nasty terms to handle but electronically + + + align:start position:0% +nasty terms to handle but electronically +uh it's a very nice way of getting a + + align:start position:0% +uh it's a very nice way of getting a + + + align:start position:0% +uh it's a very nice way of getting a +feeling for Fier series but I don't have + + align:start position:0% +feeling for Fier series but I don't have + + + align:start position:0% +feeling for Fier series but I don't have +uh electronic chalk here so I just talk + + align:start position:0% +uh electronic chalk here so I just talk + + + align:start position:0% +uh electronic chalk here so I just talk +about it and draw these things for you + + align:start position:0% +about it and draw these things for you + + + align:start position:0% +about it and draw these things for you +but for example to show you what I mean + + align:start position:0% +but for example to show you what I mean + + + align:start position:0% +but for example to show you what I mean +here let me just take the first two + + align:start position:0% +here let me just take the first two + + + align:start position:0% +here let me just take the first two +terms let me plot the curve y = 4 piun * + + align:start position:0% +terms let me plot the curve y = 4 piun * + + + align:start position:0% +terms let me plot the curve y = 4 piun * +the quantity sin x + sin 3x over 3 and + + align:start position:0% +the quantity sin x + sin 3x over 3 and + + + align:start position:0% +the quantity sin x + sin 3x over 3 and +if I plot that curve which I've done + + align:start position:0% +if I plot that curve which I've done + + + align:start position:0% +if I plot that curve which I've done +here in the accentuated chalk look at + + align:start position:0% +here in the accentuated chalk look at + + + align:start position:0% +here in the accentuated chalk look at +how nicely that curve starts already to + + align:start position:0% +how nicely that curve starts already to + + + align:start position:0% +how nicely that curve starts already to +fit the graph yal F ofx you see how it + + align:start position:0% +fit the graph yal F ofx you see how it + + + align:start position:0% +fit the graph yal F ofx you see how it +fits over here no perfect fit any place + + align:start position:0% +fits over here no perfect fit any place + + + align:start position:0% +fits over here no perfect fit any place +but notice that uh by and large it fits + + align:start position:0% +but notice that uh by and large it fits + + + align:start position:0% +but notice that uh by and large it fits +the curve very nicely without too big an + + align:start position:0% +the curve very nicely without too big an + + + align:start position:0% +the curve very nicely without too big an +error all the way along here it has + + align:start position:0% +error all the way along here it has + + + align:start position:0% +error all the way along here it has +roughly the right shape and notice also + + align:start position:0% +roughly the right shape and notice also + + + align:start position:0% +roughly the right shape and notice also +it goes through the + + align:start position:0% +it goes through the + + + align:start position:0% +it goes through the +origin see because when X is Zer capital + + align:start position:0% +origin see because when X is Zer capital + + + align:start position:0% +origin see because when X is Zer capital +f of x is zero and that's exactly the + + align:start position:0% +f of x is zero and that's exactly the + + + align:start position:0% +f of x is zero and that's exactly the +average of the jump over here see you + + align:start position:0% +average of the jump over here see you + + + align:start position:0% +average of the jump over here see you +jump from minus one to one so the origin + + align:start position:0% +jump from minus one to one so the origin + + + align:start position:0% +jump from minus one to one so the origin +is the average over here by the way even + + align:start position:0% +is the average over here by the way even + + + align:start position:0% +is the average over here by the way even +though I don't draw very well what I + + align:start position:0% +though I don't draw very well what I + + + align:start position:0% +though I don't draw very well what I +have tried to do here is show what + + align:start position:0% +have tried to do here is show what + + + align:start position:0% +have tried to do here is show what +happens if I tack on just a couple of + + align:start position:0% +happens if I tack on just a couple of + + + align:start position:0% +happens if I tack on just a couple of +more terms I've tacked on to this the + + align:start position:0% +more terms I've tacked on to this the + + + align:start position:0% +more terms I've tacked on to this the +term sin 5X X over 5 and sin 7x over 7 + + align:start position:0% +term sin 5X X over 5 and sin 7x over 7 + + + align:start position:0% +term sin 5X X over 5 and sin 7x over 7 +and then the graph would look something + + align:start position:0% +and then the graph would look something + + + align:start position:0% +and then the graph would look something +like this you see how nicely this starts + + align:start position:0% +like this you see how nicely this starts + + + align:start position:0% +like this you see how nicely this starts +to fit it fits very nicely along here + + align:start position:0% +to fit it fits very nicely along here + + + align:start position:0% +to fit it fits very nicely along here +but wherever there's a jump it jumps to + + align:start position:0% +but wherever there's a jump it jumps to + + + align:start position:0% +but wherever there's a jump it jumps to +the it averages out this way by the way + + align:start position:0% +the it averages out this way by the way + + + align:start position:0% +the it averages out this way by the way +one other observation obviously the + + align:start position:0% +one other observation obviously the + + + align:start position:0% +one other observation obviously the +function that I'm constructing here is + + align:start position:0% +function that I'm constructing here is + + + align:start position:0% +function that I'm constructing here is +periodic with Period 2 pi if I replace X + + align:start position:0% +periodic with Period 2 pi if I replace X + + + align:start position:0% +periodic with Period 2 pi if I replace X +by x + 2 pi I don't change the sign any + + align:start position:0% +by x + 2 pi I don't change the sign any + + + align:start position:0% +by x + 2 pi I don't change the sign any +and so obvious the function which I'm + + align:start position:0% +and so obvious the function which I'm + + + align:start position:0% +and so obvious the function which I'm +calling capital F ofx represents More + + align:start position:0% +calling capital F ofx represents More + + + align:start position:0% +calling capital F ofx represents More +Than This given function rather it + + align:start position:0% +Than This given function rather it + + + align:start position:0% +Than This given function rather it +represents the given function reproduced + + align:start position:0% +represents the given function reproduced + + + align:start position:0% +represents the given function reproduced +infinitely in both directions with + + align:start position:0% +infinitely in both directions with + + + align:start position:0% +infinitely in both directions with +Period 2 pi but again I'll leave that + + align:start position:0% +Period 2 pi but again I'll leave that + + + align:start position:0% +Period 2 pi but again I'll leave that +for the exercises to summarize what's + + align:start position:0% +for the exercises to summarize what's + + + align:start position:0% +for the exercises to summarize what's +happened over here you see how nicely + + align:start position:0% +happened over here you see how nicely + + + align:start position:0% +happened over here you see how nicely +this thing fits if I actually took + + align:start position:0% +this thing fits if I actually took + + + align:start position:0% +this thing fits if I actually took +capital F ofx and computed this limit + + align:start position:0% +capital F ofx and computed this limit + + + align:start position:0% +capital F ofx and computed this limit +for each value of x what the graph would + + align:start position:0% +for each value of x what the graph would + + + align:start position:0% +for each value of x what the graph would +look like now obviously I can't get this + + align:start position:0% +look like now obviously I can't get this + + + align:start position:0% +look like now obviously I can't get this +on an oscilloscope because no matter how + + align:start position:0% +on an oscilloscope because no matter how + + + align:start position:0% +on an oscilloscope because no matter how +many terms I use no matter how large a + + align:start position:0% +many terms I use no matter how large a + + + align:start position:0% +many terms I use no matter how large a +number n is still finite but if I + + align:start position:0% +number n is still finite but if I + + + align:start position:0% +number n is still finite but if I +actually took the infinite sum the graph + + align:start position:0% +actually took the infinite sum the graph + + + align:start position:0% +actually took the infinite sum the graph +that I would get mathematically is I + + align:start position:0% +that I would get mathematically is I + + + align:start position:0% +that I would get mathematically is I +would actually get the straight line x + + align:start position:0% +would actually get the straight line x + + + align:start position:0% +would actually get the straight line x +equals I'm sorry + + align:start position:0% +equals I'm sorry + + + align:start position:0% +equals I'm sorry +yal-1 from minus pi to 0 it would be X Y + + align:start position:0% +yal-1 from minus pi to 0 it would be X Y + + + align:start position:0% +yal-1 from minus pi to 0 it would be X Y += positive 1 from 0 to Pi and at zero at + + align:start position:0% += positive 1 from 0 to Pi and at zero at + + + align:start position:0% += positive 1 from 0 to Pi and at zero at +zero itself the function would be zero + + align:start position:0% +zero itself the function would be zero + + + align:start position:0% +zero itself the function would be zero +you see it split + + align:start position:0% +you see it split + + + align:start position:0% +you see it split +the Gap it splits the jump and then of + + align:start position:0% +the Gap it splits the jump and then of + + + align:start position:0% +the Gap it splits the jump and then of +course the function would repeat itself + + align:start position:0% +course the function would repeat itself + + + align:start position:0% +course the function would repeat itself +at a regular interval of uh regular + + align:start position:0% +at a regular interval of uh regular + + + align:start position:0% +at a regular interval of uh regular +period of 2 pi that this is what capital + + align:start position:0% +period of 2 pi that this is what capital + + + align:start position:0% +period of 2 pi that this is what capital +F ofx would look like if we graphed it + + align:start position:0% +F ofx would look like if we graphed it + + + align:start position:0% +F ofx would look like if we graphed it +by the way to give you an example of an + + align:start position:0% +by the way to give you an example of an + + + align:start position:0% +by the way to give you an example of an +even function if we were to use the same + + align:start position:0% +even function if we were to use the same + + + align:start position:0% +even function if we were to use the same +technique for getting the Fier series + + align:start position:0% +technique for getting the Fier series + + + align:start position:0% +technique for getting the Fier series +for f ofx equals the absolute value of x + + align:start position:0% +for f ofx equals the absolute value of x + + + align:start position:0% +for f ofx equals the absolute value of x +on the interval from minus pi to Pi it + + align:start position:0% +on the interval from minus pi to Pi it + + + align:start position:0% +on the interval from minus pi to Pi it +turns out that capital f ofx + + align:start position:0% +turns out that capital f ofx + + + align:start position:0% +turns out that capital f ofx +would be Pi / 2 minus 4 over Pi s + + align:start position:0% +would be Pi / 2 minus 4 over Pi s + + + align:start position:0% +would be Pi / 2 minus 4 over Pi s +summation Over N OD cine NX over n^2 by + + align:start position:0% +summation Over N OD cine NX over n^2 by + + + align:start position:0% +summation Over N OD cine NX over n^2 by +the way if this looks a little bit like + + align:start position:0% +the way if this looks a little bit like + + + align:start position:0% +the way if this looks a little bit like +the previous problem notice that this is + + align:start position:0% +the previous problem notice that this is + + + align:start position:0% +the previous problem notice that this is +more than just coincidence if you + + align:start position:0% +more than just coincidence if you + + + align:start position:0% +more than just coincidence if you +differentiate the square root of x I'm + + align:start position:0% +differentiate the square root of x I'm + + + align:start position:0% +differentiate the square root of x I'm +sorry if you differentiate the absolute + + align:start position:0% +sorry if you differentiate the absolute + + + align:start position:0% +sorry if you differentiate the absolute +value of x what is the derivative it's + + align:start position:0% +value of x what is the derivative it's + + + align:start position:0% +value of x what is the derivative it's +minus1 for x negative and positive 1 for + + align:start position:0% +minus1 for x negative and positive 1 for + + + align:start position:0% +minus1 for x negative and positive 1 for +X positive it's the function that we + + align:start position:0% +X positive it's the function that we + + + align:start position:0% +X positive it's the function that we +were just talking about before only it + + align:start position:0% +were just talking about before only it + + + align:start position:0% +were just talking about before only it +doesn't exist at x equals 0 you see uh + + align:start position:0% +doesn't exist at x equals 0 you see uh + + + align:start position:0% +doesn't exist at x equals 0 you see uh +what I'm driving at over here is that + + align:start position:0% +what I'm driving at over here is that + + + align:start position:0% +what I'm driving at over here is that +it's not surprising that + + align:start position:0% +it's not surprising that + + + align:start position:0% +it's not surprising that +the terms in here are the integrals of + + align:start position:0% +the terms in here are the integrals of + + + align:start position:0% +the terms in here are the integrals of +the terms that were in our previous + + align:start position:0% +the terms that were in our previous + + + align:start position:0% +the terms that were in our previous +summation but notice that the absolute + + align:start position:0% +summation but notice that the absolute + + + align:start position:0% +summation but notice that the absolute +value of x is an even function + + align:start position:0% +value of x is an even function + + + align:start position:0% +value of x is an even function +consequently it's the cosine terms which + + align:start position:0% +consequently it's the cosine terms which + + + align:start position:0% +consequently it's the cosine terms which +appear here rather than the S terms and + + align:start position:0% +appear here rather than the S terms and + + + align:start position:0% +appear here rather than the S terms and +again I've run the risk of drawing my + + align:start position:0% +again I've run the risk of drawing my + + + align:start position:0% +again I've run the risk of drawing my +own diagrams here I have plotted this + + align:start position:0% +own diagrams here I have plotted this + + + align:start position:0% +own diagrams here I have plotted this +for n = 3 meaning I've plotted y = < / 2 + + align:start position:0% +for n = 3 meaning I've plotted y = < / 2 + + + align:start position:0% +for n = 3 meaning I've plotted y = < / 2 +- 4 piun * the quantity cine X plus + + align:start position:0% +- 4 piun * the quantity cine X plus + + + align:start position:0% +- 4 piun * the quantity cine X plus +cosine 3x over 9 and that's represented + + align:start position:0% +cosine 3x over 9 and that's represented + + + align:start position:0% +cosine 3x over 9 and that's represented +by this curve drawn in the accentuated + + align:start position:0% +by this curve drawn in the accentuated + + + align:start position:0% +by this curve drawn in the accentuated +shock over here and again notice how + + align:start position:0% +shock over here and again notice how + + + align:start position:0% +shock over here and again notice how +even for just a small number of terms we + + align:start position:0% +even for just a small number of terms we + + + align:start position:0% +even for just a small number of terms we +have already captured in the lodge the + + align:start position:0% +have already captured in the lodge the + + + align:start position:0% +have already captured in the lodge the +shape of the curve y equals the absolute + + align:start position:0% +shape of the curve y equals the absolute + + + align:start position:0% +shape of the curve y equals the absolute +value of x which by the way contrast + + align:start position:0% +value of x which by the way contrast + + + align:start position:0% +value of x which by the way contrast +very sharply with power series remember + + align:start position:0% +very sharply with power series remember + + + align:start position:0% +very sharply with power series remember +how power series worked first of all you + + align:start position:0% +how power series worked first of all you + + + align:start position:0% +how power series worked first of all you +had to require that the function that + + align:start position:0% +had to require that the function that + + + align:start position:0% +had to require that the function that +you were talking about possess + + align:start position:0% +you were talking about possess + + + align:start position:0% +you were talking about possess +derivatives of all orders secondly when + + align:start position:0% +derivatives of all orders secondly when + + + align:start position:0% +derivatives of all orders secondly when +you wanted to fit the function by its + + align:start position:0% +you wanted to fit the function by its + + + align:start position:0% +you wanted to fit the function by its +power series you picked a particular + + align:start position:0% +power series you picked a particular + + + align:start position:0% +power series you picked a particular +Point remember what you got you first + + align:start position:0% +Point remember what you got you first + + + align:start position:0% +Point remember what you got you first +got a tangent line approximation then + + align:start position:0% +got a tangent line approximation then + + + align:start position:0% +got a tangent line approximation then +you got a quadratic approximation that + + align:start position:0% +you got a quadratic approximation that + + + align:start position:0% +you got a quadratic approximation that +fit the curve in a neighborhood of this + + align:start position:0% +fit the curve in a neighborhood of this + + + align:start position:0% +fit the curve in a neighborhood of this +point better than the straight line did + + align:start position:0% +point better than the straight line did + + + align:start position:0% +point better than the straight line did +but after a while the thing would sag + + align:start position:0% +but after a while the thing would sag + + + align:start position:0% +but after a while the thing would sag +off then you added a cubic + + align:start position:0% +off then you added a cubic + + + align:start position:0% +off then you added a cubic +term and that fit even better for a + + align:start position:0% +term and that fit even better for a + + + align:start position:0% +term and that fit even better for a +while and then again something weird + + align:start position:0% +while and then again something weird + + + align:start position:0% +while and then again something weird +might happen and you kept on going like + + align:start position:0% +might happen and you kept on going like + + + align:start position:0% +might happen and you kept on going like +this so that ultimately even though you + + align:start position:0% +this so that ultimately even though you + + + align:start position:0% +this so that ultimately even though you +had uniform convergence what you were + + align:start position:0% +had uniform convergence what you were + + + align:start position:0% +had uniform convergence what you were +doing was you were getting a splendid + + align:start position:0% +doing was you were getting a splendid + + + align:start position:0% +doing was you were getting a splendid +Fit near one particular point and slowly + + align:start position:0% +Fit near one particular point and slowly + + + align:start position:0% +Fit near one particular point and slowly +but + + align:start position:0% +but + + + align:start position:0% +but +surely and actually very very slowly and + + align:start position:0% +surely and actually very very slowly and + + + align:start position:0% +surely and actually very very slowly and +and also actually very surely but you + + align:start position:0% +and also actually very surely but you + + + align:start position:0% +and also actually very surely but you +may not have noticed it these + + align:start position:0% +may not have noticed it these + + + align:start position:0% +may not have noticed it these +approximations were starting to fit + + align:start position:0% +approximations were starting to fit + + + align:start position:0% +approximations were starting to fit +better and better as you went out + + align:start position:0% +better and better as you went out + + + align:start position:0% +better and better as you went out +here but the least Square approximations + + align:start position:0% +here but the least Square approximations + + + align:start position:0% +here but the least Square approximations +would not be too good in other words out + + align:start position:0% +would not be too good in other words out + + + align:start position:0% +would not be too good in other words out +here someplace there were starting to + + align:start position:0% +here someplace there were starting to + + + align:start position:0% +here someplace there were starting to +become some drastically large errors on + + align:start position:0% +become some drastically large errors on + + + align:start position:0% +become some drastically large errors on +the other hand the Fier representation + + align:start position:0% +the other hand the Fier representation + + + align:start position:0% +the other hand the Fier representation +does what it fits the curve that you're + + align:start position:0% +does what it fits the curve that you're + + + align:start position:0% +does what it fits the curve that you're +talking + + align:start position:0% +talking + + + align:start position:0% +talking +about very very nicely very very quickly + + align:start position:0% +about very very nicely very very quickly + + + align:start position:0% +about very very nicely very very quickly +and this is why one reason why Fier + + align:start position:0% +and this is why one reason why Fier + + + align:start position:0% +and this is why one reason why Fier +series are as powerful as they are and + + align:start position:0% +series are as powerful as they are and + + + align:start position:0% +series are as powerful as they are and +by the way again to end on a nice theme + + align:start position:0% +by the way again to end on a nice theme + + + align:start position:0% +by the way again to end on a nice theme +Fier series probably have as much space + + align:start position:0% +Fier series probably have as much space + + + align:start position:0% +Fier series probably have as much space +devoted to them in pure mathematics as + + align:start position:0% +devoted to them in pure mathematics as + + + align:start position:0% +devoted to them in pure mathematics as +they do in Applied Mathematics it's a + + align:start position:0% +they do in Applied Mathematics it's a + + + align:start position:0% +they do in Applied Mathematics it's a +beautiful topic from both points of view + + align:start position:0% +beautiful topic from both points of view + + + align:start position:0% +beautiful topic from both points of view +but I felt that for our lesson today + + align:start position:0% +but I felt that for our lesson today + + + align:start position:0% +but I felt that for our lesson today +since it is a Finishing Touch to + + align:start position:0% +since it is a Finishing Touch to + + + align:start position:0% +since it is a Finishing Touch to +essentially the equivalent of three plus + + align:start position:0% +essentially the equivalent of three plus + + + align:start position:0% +essentially the equivalent of three plus +semesters of calculus that we suj the + + align:start position:0% +semesters of calculus that we suj the + + + align:start position:0% +semesters of calculus that we suj the +position the old and the new and show + + align:start position:0% +position the old and the new and show + + + align:start position:0% +position the old and the new and show +the peaceful coexistence versus this + + align:start position:0% +the peaceful coexistence versus this + + + align:start position:0% +the peaceful coexistence versus this +idea of polarization where you either + + align:start position:0% +idea of polarization where you either + + + align:start position:0% +idea of polarization where you either +have to be a traditionalist or a + + align:start position:0% +have to be a traditionalist or a + + + align:start position:0% +have to be a traditionalist or a +modernist where you either have to be an + + align:start position:0% +modernist where you either have to be an + + + align:start position:0% +modernist where you either have to be an +applied man or a purist that all of + + align:start position:0% +applied man or a purist that all of + + + align:start position:0% +applied man or a purist that all of +these ideas mingle side by side and + + align:start position:0% +these ideas mingle side by side and + + + align:start position:0% +these ideas mingle side by side and +about the only choice you have is a + + align:start position:0% +about the only choice you have is a + + + align:start position:0% +about the only choice you have is a +human being depending on what your + + align:start position:0% +human being depending on what your + + + align:start position:0% +human being depending on what your +interests are is What proportion you're + + align:start position:0% +interests are is What proportion you're + + + align:start position:0% +interests are is What proportion you're +going to mix them in well at any rate + + align:start position:0% +going to mix them in well at any rate + + + align:start position:0% +going to mix them in well at any rate +this brings us to the part of the course + + align:start position:0% +this brings us to the part of the course + + + align:start position:0% +this brings us to the part of the course +that always gives me a little bit of + + align:start position:0% +that always gives me a little bit of + + + align:start position:0% +that always gives me a little bit of +remorse and that is I hate to let my + + align:start position:0% +remorse and that is I hate to let my + + + align:start position:0% +remorse and that is I hate to let my +captive audience go we have now been + + align:start position:0% +captive audience go we have now been + + + align:start position:0% +captive audience go we have now been +through as I say the equivalent of a + + align:start position:0% +through as I say the equivalent of a + + + align:start position:0% +through as I say the equivalent of a +couple of years of mathematics together + + align:start position:0% +couple of years of mathematics together + + + align:start position:0% +couple of years of mathematics together +it has been a great pleasure for me I + + align:start position:0% +it has been a great pleasure for me I + + + align:start position:0% +it has been a great pleasure for me I +hope it has been for you and once again + + align:start position:0% +hope it has been for you and once again + + + align:start position:0% +hope it has been for you and once again +I would like to thank the everybody who + + align:start position:0% +I would like to thank the everybody who + + + align:start position:0% +I would like to thank the everybody who +has worked with me on this but in + + align:start position:0% +has worked with me on this but in + + + align:start position:0% +has worked with me on this but in +particular the usual three people who + + align:start position:0% +particular the usual three people who + + + align:start position:0% +particular the usual three people who +have been with me through thick and thin + + align:start position:0% +have been with me through thick and thin + + + align:start position:0% +have been with me through thick and thin +on this John Fitch our project + + align:start position:0% +on this John Fitch our project + + + align:start position:0% +on this John Fitch our project +self-study + + align:start position:0% +self-study + + + align:start position:0% +self-study +manager who has also done a lot of work + + align:start position:0% +manager who has also done a lot of work + + + align:start position:0% +manager who has also done a lot of work +with me and helping me write the study + + align:start position:0% +with me and helping me write the study + + + align:start position:0% +with me and helping me write the study +guide who has given me a lot of advice + + align:start position:0% +guide who has given me a lot of advice + + + align:start position:0% +guide who has given me a lot of advice +on how to give these lectures and how to + + align:start position:0% +on how to give these lectures and how to + + + align:start position:0% +on how to give these lectures and how to +prepare them for the taping and has also + + align:start position:0% +prepare them for the taping and has also + + + align:start position:0% +prepare them for the taping and has also +been our director for the taping to miss + + align:start position:0% +been our director for the taping to miss + + + align:start position:0% +been our director for the taping to miss +Alise peler who in addition to her usual + + align:start position:0% +Alise peler who in addition to her usual + + + align:start position:0% +Alise peler who in addition to her usual +secretarial work has typed much of our + + align:start position:0% +secretarial work has typed much of our + + + align:start position:0% +secretarial work has typed much of our +study guide and has worked with the uh + + align:start position:0% +study guide and has worked with the uh + + + align:start position:0% +study guide and has worked with the uh +as a video technician for us and to our + + align:start position:0% +as a video technician for us and to our + + + align:start position:0% +as a video technician for us and to our +chief uh I just call him chief of Audi + + align:start position:0% +chief uh I just call him chief of Audi + + + align:start position:0% +chief uh I just call him chief of Audi +visual uh effects at the center here + + align:start position:0% +visual uh effects at the center here + + + align:start position:0% +visual uh effects at the center here +Charles patteron I am particularly + + align:start position:0% +Charles patteron I am particularly + + + align:start position:0% +Charles patteron I am particularly +indebted to these three people indebted + + align:start position:0% +indebted to these three people indebted + + + align:start position:0% +indebted to these three people indebted +to a lot of other people I thank you all + + align:start position:0% +to a lot of other people I thank you all + + + align:start position:0% +to a lot of other people I thank you all +for bearing with me this long and I hope + + align:start position:0% +for bearing with me this long and I hope + + + align:start position:0% +for bearing with me this long and I hope +that our paths will cross + + align:start position:0% + + + + align:start position:0% + +again funding for the publication of + + align:start position:0% +again funding for the publication of + + + align:start position:0% +again funding for the publication of +this video was provided by the Gabriella + + align:start position:0% +this video was provided by the Gabriella + + + align:start position:0% +this video was provided by the Gabriella +and Paul rosenbom + + align:start position:0% +and Paul rosenbom + + + align:start position:0% +and Paul rosenbom +foundation help ocw continue to provide + + align:start position:0% +foundation help ocw continue to provide + + + align:start position:0% +foundation help ocw continue to provide +free and open access to MIT courses by + + align:start position:0% +free and open access to MIT courses by + + + align:start position:0% +free and open access to MIT courses by +making a donation at ocw.mit.edu/donate \ No newline at end of file diff --git a/_ZZ6jwuBJxc.txt b/_ZZ6jwuBJxc.txt new file mode 100644 index 0000000000000000000000000000000000000000..b72bad341fa4e0bd88f067371a917ab40c15f116 --- /dev/null +++ b/_ZZ6jwuBJxc.txt @@ -0,0 +1,371 @@ +align:start position:0% + +the first thing I do that when I'm + + align:start position:0% +the first thing I do that when I'm + + + align:start position:0% +the first thing I do that when I'm +getting ready for the class is to go + + align:start position:0% +getting ready for the class is to go + + + align:start position:0% +getting ready for the class is to go +over the handouts and make sure they're + + align:start position:0% +over the handouts and make sure they're + + + align:start position:0% +over the handouts and make sure they're +really what I want update them um and + + align:start position:0% +really what I want update them um and + + + align:start position:0% +really what I want update them um and +and go over that then I usually have um + + align:start position:0% +and go over that then I usually have um + + + align:start position:0% +and go over that then I usually have um +sort of uh back to my theater days I + + align:start position:0% +sort of uh back to my theater days I + + + align:start position:0% +sort of uh back to my theater days I +guess a plan for the lecture that you + + align:start position:0% +guess a plan for the lecture that you + + + align:start position:0% +guess a plan for the lecture that you +know when the clicker questions are + + align:start position:0% +know when the clicker questions are + + + align:start position:0% +know when the clicker questions are +going to be what I'm showing on a + + align:start position:0% +going to be what I'm showing on a + + + align:start position:0% +going to be what I'm showing on a +PowerPoint presentation what I'm going + + align:start position:0% +PowerPoint presentation what I'm going + + + align:start position:0% +PowerPoint presentation what I'm going +to be writing on the board and so have + + align:start position:0% +to be writing on the board and so have + + + align:start position:0% +to be writing on the board and so have +it all organized there's times when I + + align:start position:0% +it all organized there's times when I + + + align:start position:0% +it all organized there's times when I +want to ask them a question and how I'm + + align:start position:0% +want to ask them a question and how I'm + + + align:start position:0% +want to ask them a question and how I'm +going to do that if we're going to have + + align:start position:0% +going to do that if we're going to have + + + align:start position:0% +going to do that if we're going to have +a demo in that particular class where + + align:start position:0% +a demo in that particular class where + + + align:start position:0% +a demo in that particular class where +it's going to fit in how it's going to + + align:start position:0% +it's going to fit in how it's going to + + + align:start position:0% +it's going to fit in how it's going to +be set up um and I like to bring I I + + align:start position:0% +be set up um and I like to bring I I + + + align:start position:0% +be set up um and I like to bring I I +love three-dimensional things so if + + align:start position:0% +love three-dimensional things so if + + + align:start position:0% +love three-dimensional things so if +we're talking about bonding I want giant + + align:start position:0% +we're talking about bonding I want giant + + + align:start position:0% +we're talking about bonding I want giant +atoms um and I'm always trying to think + + align:start position:0% +atoms um and I'm always trying to think + + + align:start position:0% +atoms um and I'm always trying to think +of things that I can bring in to use to + + align:start position:0% +of things that I can bring in to use to + + + align:start position:0% +of things that I can bring in to use to +show someone some kind of concept um and + + align:start position:0% +show someone some kind of concept um and + + + align:start position:0% +show someone some kind of concept um and +uh so I want at least once a a week to + + align:start position:0% +uh so I want at least once a a week to + + + align:start position:0% +uh so I want at least once a a week to +have some kind of demo in the class it's + + align:start position:0% +have some kind of demo in the class it's + + + align:start position:0% +have some kind of demo in the class it's +nice I also like some you know geeky + + align:start position:0% +nice I also like some you know geeky + + + align:start position:0% +nice I also like some you know geeky +Science music and other things um and + + align:start position:0% +Science music and other things um and + + + align:start position:0% +Science music and other things um and +then in the last year where I taught I + + align:start position:0% +then in the last year where I taught I + + + align:start position:0% +then in the last year where I taught I +upped the uh the bar for myself so if + + align:start position:0% +upped the uh the bar for myself so if + + + align:start position:0% +upped the uh the bar for myself so if +people are watching the most current + + align:start position:0% +people are watching the most current + + + align:start position:0% +people are watching the most current +open course whereare they will see my + + align:start position:0% +open course whereare they will see my + + + align:start position:0% +open course whereare they will see my +t-shirt collection um so I decided that + + align:start position:0% +t-shirt collection um so I decided that + + + align:start position:0% +t-shirt collection um so I decided that +in addition to thinking about the demos + + align:start position:0% +in addition to thinking about the demos + + + align:start position:0% +in addition to thinking about the demos +and the songs and what I'm writing on + + align:start position:0% +and the songs and what I'm writing on + + + align:start position:0% +and the songs and what I'm writing on +the board and and when I'm going to ask + + align:start position:0% +the board and and when I'm going to ask + + + align:start position:0% +the board and and when I'm going to ask +questions and all of these things that I + + align:start position:0% +questions and all of these things that I + + + align:start position:0% +questions and all of these things that I +needed to coordinate it with my word R + + align:start position:0% +needed to coordinate it with my word R + + + align:start position:0% +needed to coordinate it with my word R +so that was the high bar that I set for + + align:start position:0% +so that was the high bar that I set for + + + align:start position:0% +so that was the high bar that I set for +myself and that somehow the T-shirt not + + align:start position:0% +myself and that somehow the T-shirt not + + + align:start position:0% +myself and that somehow the T-shirt not +only had to be some kind of geeky + + align:start position:0% +only had to be some kind of geeky + + + align:start position:0% +only had to be some kind of geeky +chemistry thing but related somehow to + + align:start position:0% +chemistry thing but related somehow to + + + align:start position:0% +chemistry thing but related somehow to +the topic at hand so that was one of um + + align:start position:0% +the topic at hand so that was one of um + + + align:start position:0% +the topic at hand so that was one of um +that took a lot of preparation I had to + + align:start position:0% +that took a lot of preparation I had to + + + align:start position:0% +that took a lot of preparation I had to +plan so if I had to order t-shirts I had + + align:start position:0% +plan so if I had to order t-shirts I had + + + align:start position:0% +plan so if I had to order t-shirts I had +to order ahead of time so they arrived + + align:start position:0% +to order ahead of time so they arrived + + + align:start position:0% +to order ahead of time so they arrived +um and figuring out a different t-shirt + + align:start position:0% +um and figuring out a different t-shirt + + + align:start position:0% +um and figuring out a different t-shirt +per lecture that was one of the harder + + align:start position:0% +per lecture that was one of the harder + + + align:start position:0% +per lecture that was one of the harder +challenges \ No newline at end of file diff --git a/_gsDTzOpiKo.txt b/_gsDTzOpiKo.txt new file mode 100644 index 0000000000000000000000000000000000000000..73146d0ad9450164820eaeb492a3e4512b141d22 --- /dev/null +++ b/_gsDTzOpiKo.txt @@ -0,0 +1,8731 @@ +align:start position:0% + +and here in front + + align:start position:0% +and here in front + + + align:start position:0% +and here in front +you asked me whether bird song would + + align:start position:0% +you asked me whether bird song would + + + align:start position:0% +you asked me whether bird song would +count as a fixed action pattern it + + align:start position:0% +count as a fixed action pattern it + + + align:start position:0% +count as a fixed action pattern it +doesn't sound fixed this is because they + + align:start position:0% +doesn't sound fixed this is because they + + + align:start position:0% +doesn't sound fixed this is because they +learn a lot but you know that's true for + + align:start position:0% +learn a lot but you know that's true for + + + align:start position:0% +learn a lot but you know that's true for +every fixation better every instinctive + + align:start position:0% +every fixation better every instinctive + + + align:start position:0% +every fixation better every instinctive +behavior there's always some learning + + align:start position:0% +behavior there's always some learning + + + align:start position:0% +behavior there's always some learning +involved + + align:start position:0% +involved + + + align:start position:0% +involved +it's never fully formed + + align:start position:0% + + + + align:start position:0% + +walking is a fixed action pattern in us + + align:start position:0% +walking is a fixed action pattern in us + + + align:start position:0% +walking is a fixed action pattern in us +but in fact we do learn things and + + align:start position:0% + + + + align:start position:0% + +we it develops a little bit over time + + align:start position:0% +we it develops a little bit over time + + + align:start position:0% +we it develops a little bit over time +some fixed action patterns have a lot of + + align:start position:0% +some fixed action patterns have a lot of + + + align:start position:0% +some fixed action patterns have a lot of +learning and some very little + + align:start position:0% + + + + align:start position:0% + +an action like sneezing would have + + align:start position:0% +an action like sneezing would have + + + align:start position:0% +an action like sneezing would have +almost none but in fact if i look at + + align:start position:0% +almost none but in fact if i look at + + + align:start position:0% +almost none but in fact if i look at +various people even in the same family + + align:start position:0% +various people even in the same family + + + align:start position:0% +various people even in the same family +sneezing they'll all do it a little + + align:start position:0% +sneezing they'll all do it a little + + + align:start position:0% +sneezing they'll all do it a little +differently because + + align:start position:0% +differently because + + + align:start position:0% +differently because +they've learned they've added some + + align:start position:0% +they've learned they've added some + + + align:start position:0% +they've learned they've added some +learning on top of it + + align:start position:0% +learning on top of it + + + align:start position:0% +learning on top of it +so + + align:start position:0% +so + + + align:start position:0% +so +we have a few things left from last time + + align:start position:0% +we have a few things left from last time + + + align:start position:0% +we have a few things left from last time +i want to go over a few things + + align:start position:0% +i want to go over a few things + + + align:start position:0% +i want to go over a few things +examples of competition + + align:start position:0% +examples of competition + + + align:start position:0% +examples of competition +among axons during development + + align:start position:0% +among axons during development + + + align:start position:0% +among axons during development +where exons will compete for terminal + + align:start position:0% +where exons will compete for terminal + + + align:start position:0% +where exons will compete for terminal +space they're either competing for + + align:start position:0% +space they're either competing for + + + align:start position:0% +space they're either competing for +growth factors or for occupancy of + + align:start position:0% +growth factors or for occupancy of + + + align:start position:0% +growth factors or for occupancy of +synaptic sites + + align:start position:0% +synaptic sites + + + align:start position:0% +synaptic sites +but they're also contact interactions + + align:start position:0% +but they're also contact interactions + + + align:start position:0% +but they're also contact interactions +between json accents + + align:start position:0% + + + + align:start position:0% + +i changed the heading slightly but these + + align:start position:0% +i changed the heading slightly but these + + + align:start position:0% +i changed the heading slightly but these +are the same pictures you have on the + + align:start position:0% +are the same pictures you have on the + + + align:start position:0% +are the same pictures you have on the +printout + + align:start position:0% +printout + + + align:start position:0% +printout +for the last class + + align:start position:0% + + + + align:start position:0% + +we're going to go through a series of + + align:start position:0% +we're going to go through a series of + + + align:start position:0% +we're going to go through a series of +simple examples in every case there's + + align:start position:0% +simple examples in every case there's + + + align:start position:0% +simple examples in every case there's +some competition among adjacent or + + align:start position:0% +some competition among adjacent or + + + align:start position:0% +some competition among adjacent or +overlapping populations of growing axons + + align:start position:0% +overlapping populations of growing axons + + + align:start position:0% +overlapping populations of growing axons +in the developing brain + + align:start position:0% +in the developing brain + + + align:start position:0% +in the developing brain +so for example in the visual system + + align:start position:0% +so for example in the visual system + + + align:start position:0% +so for example in the visual system +the two eyes project to the geniculate + + align:start position:0% +the two eyes project to the geniculate + + + align:start position:0% +the two eyes project to the geniculate +body okay + + align:start position:0% +body okay + + + align:start position:0% +body okay +the box there indicates the geniculate + + align:start position:0% +the box there indicates the geniculate + + + align:start position:0% +the box there indicates the geniculate +body and then you see the two eyes + + align:start position:0% +body and then you see the two eyes + + + align:start position:0% +body and then you see the two eyes +and axons from the two eyes just mix + + align:start position:0% +and axons from the two eyes just mix + + + align:start position:0% +and axons from the two eyes just mix +with each other if you look with + + align:start position:0% +with each other if you look with + + + align:start position:0% +with each other if you look with +anatomical methods you see that they're + + align:start position:0% +anatomical methods you see that they're + + + align:start position:0% +anatomical methods you see that they're +overlapping okay + + align:start position:0% +overlapping okay + + + align:start position:0% +overlapping okay +but then there's a sorting out they + + align:start position:0% +but then there's a sorting out they + + + align:start position:0% +but then there's a sorting out they +appear to compete in some way + + align:start position:0% +appear to compete in some way + + + align:start position:0% +appear to compete in some way +with each other + + align:start position:0% +with each other + + + align:start position:0% +with each other +and + + align:start position:0% +and + + + align:start position:0% +and +those from the ipsilateral eye end up in + + align:start position:0% +those from the ipsilateral eye end up in + + + align:start position:0% +those from the ipsilateral eye end up in +one part of the geniculate from the + + align:start position:0% +one part of the geniculate from the + + + align:start position:0% +one part of the geniculate from the +contralateral line on the other part of + + align:start position:0% +contralateral line on the other part of + + + align:start position:0% +contralateral line on the other part of +the january so they sort out + + align:start position:0% + + + + align:start position:0% + +that also happens in the spirit + + align:start position:0% +that also happens in the spirit + + + align:start position:0% +that also happens in the spirit +colliculus + + align:start position:0% +colliculus + + + align:start position:0% +colliculus +in abnormal situations where you create + + align:start position:0% +in abnormal situations where you create + + + align:start position:0% +in abnormal situations where you create +a colliculus with + + align:start position:0% +a colliculus with + + + align:start position:0% +a colliculus with +both eyes coming in + + align:start position:0% +both eyes coming in + + + align:start position:0% +both eyes coming in +to the superficial layers + + align:start position:0% +to the superficial layers + + + align:start position:0% +to the superficial layers +now here's another example here you have + + align:start position:0% +now here's another example here you have + + + align:start position:0% +now here's another example here you have +competition between again two + + align:start position:0% +competition between again two + + + align:start position:0% +competition between again two +overlapping populations in this case as + + align:start position:0% +overlapping populations in this case as + + + align:start position:0% +overlapping populations in this case as +in the geniculate body they sort out in + + align:start position:0% +in the geniculate body they sort out in + + + align:start position:0% +in the geniculate body they sort out in +somewhat different way there's two types + + align:start position:0% +somewhat different way there's two types + + + align:start position:0% +somewhat different way there's two types +of axons + + align:start position:0% +of axons + + + align:start position:0% +of axons +and although they're initially + + align:start position:0% +and although they're initially + + + align:start position:0% +and although they're initially +overlapping + + align:start position:0% +overlapping + + + align:start position:0% +overlapping +in fact i've drawn them as if they're + + align:start position:0% +in fact i've drawn them as if they're + + + align:start position:0% +in fact i've drawn them as if they're +all + + align:start position:0% +all + + + align:start position:0% +all +separate they probably the terminal + + align:start position:0% +separate they probably the terminal + + + align:start position:0% +separate they probably the terminal +arbors would actually overlap + + align:start position:0% +arbors would actually overlap + + + align:start position:0% +arbors would actually overlap +but then + + align:start position:0% +but then + + + align:start position:0% +but then +as they mature + + align:start position:0% +as they mature + + + align:start position:0% +as they mature +one population ends up occupying the + + align:start position:0% +one population ends up occupying the + + + align:start position:0% +one population ends up occupying the +upper two-thirds of the layer and + + align:start position:0% +upper two-thirds of the layer and + + + align:start position:0% +upper two-thirds of the layer and +another population + + align:start position:0% +another population + + + align:start position:0% +another population +ends up occupying the lower third + + align:start position:0% +ends up occupying the lower third + + + align:start position:0% +ends up occupying the lower third +there is a little bit of overlap between + + align:start position:0% +there is a little bit of overlap between + + + align:start position:0% +there is a little bit of overlap between +them still + + align:start position:0% +them still + + + align:start position:0% +them still +but basically they + + align:start position:0% +but basically they + + + align:start position:0% +but basically they +they segregate into layers + + align:start position:0% +they segregate into layers + + + align:start position:0% +they segregate into layers +so not so different from the what + + align:start position:0% +so not so different from the what + + + align:start position:0% +so not so different from the what +happens in the geneculate body except in + + align:start position:0% +happens in the geneculate body except in + + + align:start position:0% +happens in the geneculate body except in +this case they're not accidents from the + + align:start position:0% +this case they're not accidents from the + + + align:start position:0% +this case they're not accidents from the +two eyes + + align:start position:0% +two eyes + + + align:start position:0% +two eyes +now they're from the same eye but + + align:start position:0% +now they're from the same eye but + + + align:start position:0% +now they're from the same eye but +they're from different types of exon + + align:start position:0% +they're from different types of exon + + + align:start position:0% +they're from different types of exon +in the same eye one is a larger axon + + align:start position:0% +in the same eye one is a larger axon + + + align:start position:0% +in the same eye one is a larger axon +okay another one is a smaller coming + + align:start position:0% +okay another one is a smaller coming + + + align:start position:0% +okay another one is a smaller coming +from smaller cells + + align:start position:0% +from smaller cells + + + align:start position:0% +from smaller cells +and they end up terminating in these + + align:start position:0% +and they end up terminating in these + + + align:start position:0% +and they end up terminating in these +different layers + + align:start position:0% + + + + align:start position:0% + +there's other + + align:start position:0% +there's other + + + align:start position:0% +there's other +cases where two populations are in the + + align:start position:0% +cases where two populations are in the + + + align:start position:0% +cases where two populations are in the +same eye + + align:start position:0% + + + + align:start position:0% + +where the because they're coming from + + align:start position:0% +where the because they're coming from + + + align:start position:0% +where the because they're coming from +different cells one axon type might grow + + align:start position:0% +different cells one axon type might grow + + + align:start position:0% +different cells one axon type might grow +bigger than the other + + align:start position:0% + + + + align:start position:0% + +and end up occupying more of the space + + align:start position:0% +and end up occupying more of the space + + + align:start position:0% +and end up occupying more of the space +than the smaller axon okay in many cases + + align:start position:0% +than the smaller axon okay in many cases + + + align:start position:0% +than the smaller axon okay in many cases +of that initially they might be very + + align:start position:0% +of that initially they might be very + + + align:start position:0% +of that initially they might be very +similar but they may end up occupying + + align:start position:0% +similar but they may end up occupying + + + align:start position:0% +similar but they may end up occupying +different amounts of space though they + + align:start position:0% +different amounts of space though they + + + align:start position:0% +different amounts of space though they +might still overlap + + align:start position:0% +might still overlap + + + align:start position:0% +might still overlap +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now we know that + + align:start position:0% +now we know that + + + align:start position:0% +now we know that +these axons form topographic maps + + align:start position:0% +these axons form topographic maps + + + align:start position:0% +these axons form topographic maps +initially we have one axon that might be + + align:start position:0% +initially we have one axon that might be + + + align:start position:0% +initially we have one axon that might be +terminating over a + + align:start position:0% + + + + align:start position:0% + +a span of the collicular space + + align:start position:0% +a span of the collicular space + + + align:start position:0% +a span of the collicular space +but then they segregate because each + + align:start position:0% +but then they segregate because each + + + align:start position:0% +but then they segregate because each +axon seems to compete best in one part + + align:start position:0% +axon seems to compete best in one part + + + align:start position:0% +axon seems to compete best in one part +of the tectum depending on the chemical + + align:start position:0% +of the tectum depending on the chemical + + + align:start position:0% +of the tectum depending on the chemical +environment okay + + align:start position:0% +environment okay + + + align:start position:0% +environment okay +so + + align:start position:0% +so + + + align:start position:0% +so +the chemical factors interact with these + + align:start position:0% +the chemical factors interact with these + + + align:start position:0% +the chemical factors interact with these +competitive interactions in sorting the + + align:start position:0% +competitive interactions in sorting the + + + align:start position:0% +competitive interactions in sorting the +axons into their proper places + + align:start position:0% + + + + align:start position:0% + +okay so + + align:start position:0% + + + + align:start position:0% + +just think of it in every case as + + align:start position:0% +just think of it in every case as + + + align:start position:0% +just think of it in every case as +a kind of competition between adjacent + + align:start position:0% +a kind of competition between adjacent + + + align:start position:0% +a kind of competition between adjacent +or overlapping populations of accents + + align:start position:0% +or overlapping populations of accents + + + align:start position:0% +or overlapping populations of accents +okay very common in development + + align:start position:0% +okay very common in development + + + align:start position:0% +okay very common in development +now let's talk about this intrinsic + + align:start position:0% +now let's talk about this intrinsic + + + align:start position:0% +now let's talk about this intrinsic +factor + + align:start position:0% +factor + + + align:start position:0% +factor +that in a cell + + align:start position:0% +that in a cell + + + align:start position:0% +that in a cell +when it's growing an axon + + align:start position:0% +when it's growing an axon + + + align:start position:0% +when it's growing an axon +can vary in its ability to compete + + align:start position:0% +can vary in its ability to compete + + + align:start position:0% +can vary in its ability to compete +okay and we call this competitive growth + + align:start position:0% +okay and we call this competitive growth + + + align:start position:0% +okay and we call this competitive growth +bigger + + align:start position:0% +bigger + + + align:start position:0% +bigger +the more growth figure an axon has + + align:start position:0% +the more growth figure an axon has + + + align:start position:0% +the more growth figure an axon has +the more it grows and the better it + + align:start position:0% +the more it grows and the better it + + + align:start position:0% +the more it grows and the better it +competes for terminal space but this can + + align:start position:0% +competes for terminal space but this can + + + align:start position:0% +competes for terminal space but this can +be modulated it can be modulated by + + align:start position:0% +be modulated it can be modulated by + + + align:start position:0% +be modulated it can be modulated by +chemical factors for example + + align:start position:0% +chemical factors for example + + + align:start position:0% +chemical factors for example +in gf + + align:start position:0% +in gf + + + align:start position:0% +in gf +in the case of + + align:start position:0% + + + + align:start position:0% + +tissue culture you can see that + + align:start position:0% +tissue culture you can see that + + + align:start position:0% +tissue culture you can see that +the cells here had a lot more growth + + align:start position:0% +the cells here had a lot more growth + + + align:start position:0% +the cells here had a lot more growth +figure in the cells here here they're + + align:start position:0% +figure in the cells here here they're + + + align:start position:0% +figure in the cells here here they're +growing short little stubby axons and + + align:start position:0% +growing short little stubby axons and + + + align:start position:0% +growing short little stubby axons and +not growing very far + + align:start position:0% +not growing very far + + + align:start position:0% +not growing very far +some of them are not growing much at all + + align:start position:0% +some of them are not growing much at all + + + align:start position:0% +some of them are not growing much at all +but if you add little growth factor + + align:start position:0% +but if you add little growth factor + + + align:start position:0% +but if you add little growth factor +they grow much more vigorously so it's + + align:start position:0% +they grow much more vigorously so it's + + + align:start position:0% +they grow much more vigorously so it's +possible then to modulate the growth + + align:start position:0% +possible then to modulate the growth + + + align:start position:0% +possible then to modulate the growth +figure + + align:start position:0% +figure + + + align:start position:0% +figure +with these chemical factors + + align:start position:0% + + + + align:start position:0% + +there's also factors intrinsic to the + + align:start position:0% +there's also factors intrinsic to the + + + align:start position:0% +there's also factors intrinsic to the +cells and in fact something like ngf is + + align:start position:0% +cells and in fact something like ngf is + + + align:start position:0% +cells and in fact something like ngf is +synthesized by some neurons also so + + align:start position:0% +synthesized by some neurons also so + + + align:start position:0% +synthesized by some neurons also so +sometimes they make their own growth + + align:start position:0% +sometimes they make their own growth + + + align:start position:0% +sometimes they make their own growth +factor and then how much they make will + + align:start position:0% +factor and then how much they make will + + + align:start position:0% +factor and then how much they make will +determine how they grow + + align:start position:0% +determine how they grow + + + align:start position:0% +determine how they grow +they might respond separately to other + + align:start position:0% +they might respond separately to other + + + align:start position:0% +they might respond separately to other +growth factors in the environment + + align:start position:0% +growth factors in the environment + + + align:start position:0% +growth factors in the environment +okay but now there's a couple of other + + align:start position:0% +okay but now there's a couple of other + + + align:start position:0% +okay but now there's a couple of other +things i want to consider briefly one is + + align:start position:0% +things i want to consider briefly one is + + + align:start position:0% +things i want to consider briefly one is +later in development + + align:start position:0% +later in development + + + align:start position:0% +later in development +activity can affect + + align:start position:0% +activity can affect + + + align:start position:0% +activity can affect +the growth figure of the axon + + align:start position:0% +the growth figure of the axon + + + align:start position:0% +the growth figure of the axon +so for example axons representing the + + align:start position:0% +so for example axons representing the + + + align:start position:0% +so for example axons representing the +two eyes + + align:start position:0% +two eyes + + + align:start position:0% +two eyes +grow into the geniculite geniculi by + + align:start position:0% +grow into the geniculite geniculi by + + + align:start position:0% +grow into the geniculite geniculi by +segregate into different laminae + + align:start position:0% +segregate into different laminae + + + align:start position:0% +segregate into different laminae +so you have different laminae all + + align:start position:0% +so you have different laminae all + + + align:start position:0% +so you have different laminae all +but all representing the same place in + + align:start position:0% +but all representing the same place in + + + align:start position:0% +but all representing the same place in +the visual field + + align:start position:0% +the visual field + + + align:start position:0% +the visual field +so the corresponding areas of the two + + align:start position:0% +so the corresponding areas of the two + + + align:start position:0% +so the corresponding areas of the two +retinas okay now all the cells in that + + align:start position:0% +retinas okay now all the cells in that + + + align:start position:0% +retinas okay now all the cells in that +column + + align:start position:0% +column + + + align:start position:0% +column +from + + align:start position:0% +from + + + align:start position:0% +from +representing the contralateral and the + + align:start position:0% +representing the contralateral and the + + + align:start position:0% +representing the contralateral and the +ipsilateral eye will project to the same + + align:start position:0% +ipsilateral eye will project to the same + + + align:start position:0% +ipsilateral eye will project to the same +region of the cortex + + align:start position:0% +region of the cortex + + + align:start position:0% +region of the cortex +where we know there's another + + align:start position:0% +where we know there's another + + + align:start position:0% +where we know there's another +topographic map of the visual world but + + align:start position:0% +topographic map of the visual world but + + + align:start position:0% +topographic map of the visual world but +now + + align:start position:0% +now + + + align:start position:0% +now +and again they grow in and they overlap + + align:start position:0% +and again they grow in and they overlap + + + align:start position:0% +and again they grow in and they overlap +with each other + + align:start position:0% +with each other + + + align:start position:0% +with each other +early in development + + align:start position:0% +early in development + + + align:start position:0% +early in development +and then + + align:start position:0% +and then + + + align:start position:0% +and then +just like in the geniculate body they + + align:start position:0% +just like in the geniculate body they + + + align:start position:0% +just like in the geniculate body they +segregate but now they segregate into + + align:start position:0% +segregate but now they segregate into + + + align:start position:0% +segregate but now they segregate into +adjacent slabs of tissue we call them + + align:start position:0% +adjacent slabs of tissue we call them + + + align:start position:0% +adjacent slabs of tissue we call them +cortical columns they're really sort of + + align:start position:0% +cortical columns they're really sort of + + + align:start position:0% +cortical columns they're really sort of +like slabs and if you look at it from + + align:start position:0% +like slabs and if you look at it from + + + align:start position:0% +like slabs and if you look at it from +the surface they're like zebra stripes + + align:start position:0% +the surface they're like zebra stripes + + + align:start position:0% +the surface they're like zebra stripes +many of you have seen those pictures + + align:start position:0% +many of you have seen those pictures + + + align:start position:0% +many of you have seen those pictures +of representation of the two eyes in the + + align:start position:0% +of representation of the two eyes in the + + + align:start position:0% +of representation of the two eyes in the +visual cortex but what i want to bring + + align:start position:0% +visual cortex but what i want to bring + + + align:start position:0% +visual cortex but what i want to bring +out here is that + + align:start position:0% +out here is that + + + align:start position:0% +out here is that +if the activity of the two eyes is + + align:start position:0% +if the activity of the two eyes is + + + align:start position:0% +if the activity of the two eyes is +abnormally different + + align:start position:0% + + + + align:start position:0% + +so for some reason perhaps the person + + align:start position:0% +so for some reason perhaps the person + + + align:start position:0% +so for some reason perhaps the person +asked your business and he starts + + align:start position:0% +asked your business and he starts + + + align:start position:0% +asked your business and he starts +suppressing vision then why + + align:start position:0% +suppressing vision then why + + + align:start position:0% +suppressing vision then why +or one eye is patched + + align:start position:0% +or one eye is patched + + + align:start position:0% +or one eye is patched +or because of an injury or something + + align:start position:0% +or because of an injury or something + + + align:start position:0% +or because of an injury or something +okay + + align:start position:0% +okay + + + align:start position:0% +okay +the eye with the activity with the more + + align:start position:0% +the eye with the activity with the more + + + align:start position:0% +the eye with the activity with the more +activity will end up occupying more + + align:start position:0% +activity will end up occupying more + + + align:start position:0% +activity will end up occupying more +space in the eye with less activity will + + align:start position:0% +space in the eye with less activity will + + + align:start position:0% +space in the eye with less activity will +occupy less space + + align:start position:0% + + + + align:start position:0% + +children with strabismus + + align:start position:0% +children with strabismus + + + align:start position:0% +children with strabismus +will often suppress + + align:start position:0% +will often suppress + + + align:start position:0% +will often suppress +cortical vision in one eye at least + + align:start position:0% +cortical vision in one eye at least + + + align:start position:0% +cortical vision in one eye at least +foveal vision + + align:start position:0% +foveal vision + + + align:start position:0% +foveal vision +and one eye loses acuity + + align:start position:0% +and one eye loses acuity + + + align:start position:0% +and one eye loses acuity +the other eye will actually have + + align:start position:0% +the other eye will actually have + + + align:start position:0% +the other eye will actually have +somewhat increased acuity + + align:start position:0% +somewhat increased acuity + + + align:start position:0% +somewhat increased acuity +so if you test the child with the two + + align:start position:0% +so if you test the child with the two + + + align:start position:0% +so if you test the child with the two +eyes he comes in for an eye test when he + + align:start position:0% +eyes he comes in for an eye test when he + + + align:start position:0% +eyes he comes in for an eye test when he +starts school they see very different + + align:start position:0% +starts school they see very different + + + align:start position:0% +starts school they see very different +acuity in the two eyes it's because he's + + align:start position:0% +acuity in the two eyes it's because he's + + + align:start position:0% +acuity in the two eyes it's because he's +normally suppressing vision in one eye i + + align:start position:0% +normally suppressing vision in one eye i + + + align:start position:0% +normally suppressing vision in one eye i +had that when i entered school + + align:start position:0% +had that when i entered school + + + align:start position:0% +had that when i entered school +you know + + align:start position:0% +you know + + + align:start position:0% +you know +so what do they do + + align:start position:0% +so what do they do + + + align:start position:0% +so what do they do +they patch the good eye + + align:start position:0% +they patch the good eye + + + align:start position:0% +they patch the good eye +they in to increase activity + + align:start position:0% +they in to increase activity + + + align:start position:0% +they in to increase activity +now if i had any strabismus it wasn't + + align:start position:0% +now if i had any strabismus it wasn't + + + align:start position:0% +now if i had any strabismus it wasn't +noticeable + + align:start position:0% +noticeable + + + align:start position:0% +noticeable +and i could have coordinated the two + + align:start position:0% +and i could have coordinated the two + + + align:start position:0% +and i could have coordinated the two +eyes are coordinated + + align:start position:0% +eyes are coordinated + + + align:start position:0% +eyes are coordinated +but with that patching over time the + + align:start position:0% +but with that patching over time the + + + align:start position:0% +but with that patching over time the +acuity got better and better + + align:start position:0% +acuity got better and better + + + align:start position:0% +acuity got better and better +in the eye that it was so bad in + + align:start position:0% +in the eye that it was so bad in + + + align:start position:0% +in the eye that it was so bad in +the other i stayed about the same and i + + align:start position:0% +the other i stayed about the same and i + + + align:start position:0% +the other i stayed about the same and i +ended up with about + + align:start position:0% +ended up with about + + + align:start position:0% +ended up with about +instead of 2020 i had 2015 in the left + + align:start position:0% +instead of 2020 i had 2015 in the left + + + align:start position:0% +instead of 2020 i had 2015 in the left +eye better than normal + + align:start position:0% +eye better than normal + + + align:start position:0% +eye better than normal +and 20 30 in the other eye + + align:start position:0% + + + + align:start position:0% + +so apparently the columns representing + + align:start position:0% +so apparently the columns representing + + + align:start position:0% +so apparently the columns representing +the two eyes are still a little bit + + align:start position:0% +the two eyes are still a little bit + + + align:start position:0% +the two eyes are still a little bit +different + + align:start position:0% + + + + align:start position:0% + +that shows how activity and there's + + align:start position:0% +that shows how activity and there's + + + align:start position:0% +that shows how activity and there's +other examples of how activity can + + align:start position:0% +other examples of how activity can + + + align:start position:0% +other examples of how activity can +influence accidental growth that tends + + align:start position:0% +influence accidental growth that tends + + + align:start position:0% +influence accidental growth that tends +to happen of course later in development + + align:start position:0% +to happen of course later in development + + + align:start position:0% +to happen of course later in development +when the axons are more mature but + + align:start position:0% +when the axons are more mature but + + + align:start position:0% +when the axons are more mature but +they're still growing still competing + + align:start position:0% +they're still growing still competing + + + align:start position:0% +they're still growing still competing +okay you can also vary + + align:start position:0% +okay you can also vary + + + align:start position:0% +okay you can also vary +competitive growth figure with a lesion + + align:start position:0% +competitive growth figure with a lesion + + + align:start position:0% +competitive growth figure with a lesion +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and + + align:start position:0% + + + + align:start position:0% + +i'm going to + + align:start position:0% +i'm going to + + + align:start position:0% +i'm going to +illustrate that by showing you what we + + align:start position:0% +illustrate that by showing you what we + + + align:start position:0% +illustrate that by showing you what we +call the pruning effect in axons + + align:start position:0% +call the pruning effect in axons + + + align:start position:0% +call the pruning effect in axons +let's take the top and first + + align:start position:0% +let's take the top and first + + + align:start position:0% +let's take the top and first +this just illustrates how we + + align:start position:0% +this just illustrates how we + + + align:start position:0% +this just illustrates how we +conceptualize it + + align:start position:0% +conceptualize it + + + align:start position:0% +conceptualize it +that early in development the axon is + + align:start position:0% +that early in development the axon is + + + align:start position:0% +that early in development the axon is +just starting to grow terminals it + + align:start position:0% +just starting to grow terminals it + + + align:start position:0% +just starting to grow terminals it +hasn't formed very many yet its growth + + align:start position:0% +hasn't formed very many yet its growth + + + align:start position:0% +hasn't formed very many yet its growth +figure is very high it's growing + + align:start position:0% + + + + align:start position:0% + +in all the local sorry all the local + + align:start position:0% +in all the local sorry all the local + + + align:start position:0% +in all the local sorry all the local +directions from this terminal + + align:start position:0% +directions from this terminal + + + align:start position:0% +directions from this terminal +until finally + + align:start position:0% +until finally + + + align:start position:0% +until finally +once it reaches a certain quantity of + + align:start position:0% +once it reaches a certain quantity of + + + align:start position:0% +once it reaches a certain quantity of +its terminal arbor the growth figure now + + align:start position:0% +its terminal arbor the growth figure now + + + align:start position:0% +its terminal arbor the growth figure now +is very low + + align:start position:0% +is very low + + + align:start position:0% +is very low +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so it appears that the ac these axons or + + align:start position:0% +so it appears that the ac these axons or + + + align:start position:0% +so it appears that the ac these axons or +cells are programmed to form a certain + + align:start position:0% +cells are programmed to form a certain + + + align:start position:0% +cells are programmed to form a certain +size of terminal arbor and we have a + + align:start position:0% +size of terminal arbor and we have a + + + align:start position:0% +size of terminal arbor and we have a +number of experiments that indicate that + + align:start position:0% +number of experiments that indicate that + + + align:start position:0% +number of experiments that indicate that +so to test that + + align:start position:0% +so to test that + + + align:start position:0% +so to test that +okay + + align:start position:0% +okay + + + align:start position:0% +okay +we can take an animal that's formed the + + align:start position:0% +we can take an animal that's formed the + + + align:start position:0% +we can take an animal that's formed the +terminal arbors + + align:start position:0% +terminal arbors + + + align:start position:0% +terminal arbors +but now we'll create a lesion we'll make + + align:start position:0% +but now we'll create a lesion we'll make + + + align:start position:0% +but now we'll create a lesion we'll make +a lesion in part of the brain + + align:start position:0% +a lesion in part of the brain + + + align:start position:0% +a lesion in part of the brain +that will + + align:start position:0% +that will + + + align:start position:0% +that will +kill some of the ann arbor + + align:start position:0% +kill some of the ann arbor + + + align:start position:0% +kill some of the ann arbor +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now i've done this for conceptual + + align:start position:0% +now i've done this for conceptual + + + align:start position:0% +now i've done this for conceptual +purposes + + align:start position:0% +purposes + + + align:start position:0% +purposes +but i'm not going to go over all the + + align:start position:0% +but i'm not going to go over all the + + + align:start position:0% +but i'm not going to go over all the +experiments right now + + align:start position:0% + + + + align:start position:0% + +what that does is it increases the + + align:start position:0% +what that does is it increases the + + + align:start position:0% +what that does is it increases the +growth figure + + align:start position:0% +growth figure + + + align:start position:0% +growth figure +in the remaining branches so if it has a + + align:start position:0% +in the remaining branches so if it has a + + + align:start position:0% +in the remaining branches so if it has a +collateral branch here for example this + + align:start position:0% +collateral branch here for example this + + + align:start position:0% +collateral branch here for example this +could be in the thalamus and this could + + align:start position:0% +could be in the thalamus and this could + + + align:start position:0% +could be in the thalamus and this could +be in the tectum it will now increase + + align:start position:0% +be in the tectum it will now increase + + + align:start position:0% +be in the tectum it will now increase +its projections + + align:start position:0% +its projections + + + align:start position:0% +its projections +and those collaterals they'll grow + + align:start position:0% +and those collaterals they'll grow + + + align:start position:0% +and those collaterals they'll grow +bigger than normal + + align:start position:0% +bigger than normal + + + align:start position:0% +bigger than normal +as if in compensation for the loss of + + align:start position:0% +as if in compensation for the loss of + + + align:start position:0% +as if in compensation for the loss of +the arbors here + + align:start position:0% +the arbors here + + + align:start position:0% +the arbors here +and these will grow more also so you'll + + align:start position:0% +and these will grow more also so you'll + + + align:start position:0% +and these will grow more also so you'll +end up with an arbor a total arbor size + + align:start position:0% +end up with an arbor a total arbor size + + + align:start position:0% +end up with an arbor a total arbor size +about the same as it would have been + + align:start position:0% +about the same as it would have been + + + align:start position:0% +about the same as it would have been +normally + + align:start position:0% +normally + + + align:start position:0% +normally +okay but now it's growing them in a + + align:start position:0% +okay but now it's growing them in a + + + align:start position:0% +okay but now it's growing them in a +different pattern because of the damage + + align:start position:0% +different pattern because of the damage + + + align:start position:0% +different pattern because of the damage +so it's not that different from pruning + + align:start position:0% +so it's not that different from pruning + + + align:start position:0% +so it's not that different from pruning +a tree + + align:start position:0% +a tree + + + align:start position:0% +a tree +if you have certain trees show pruning + + align:start position:0% +if you have certain trees show pruning + + + align:start position:0% +if you have certain trees show pruning +effects some do not + + align:start position:0% +effects some do not + + + align:start position:0% +effects some do not +okay a maple tree for example if you + + align:start position:0% +okay a maple tree for example if you + + + align:start position:0% +okay a maple tree for example if you +prune the top of it when it's young + + align:start position:0% +prune the top of it when it's young + + + align:start position:0% +prune the top of it when it's young +you can create a better shade tree + + align:start position:0% +you can create a better shade tree + + + align:start position:0% +you can create a better shade tree +because the lower branches will sprout + + align:start position:0% +because the lower branches will sprout + + + align:start position:0% +because the lower branches will sprout +more it'll become a wider tree + + align:start position:0% +more it'll become a wider tree + + + align:start position:0% +more it'll become a wider tree +and won't just grow like a a tall + + align:start position:0% +and won't just grow like a a tall + + + align:start position:0% +and won't just grow like a a tall +slender maple tree it'll be a broad + + align:start position:0% +slender maple tree it'll be a broad + + + align:start position:0% +slender maple tree it'll be a broad +maple tree in your front lawn + + align:start position:0% +maple tree in your front lawn + + + align:start position:0% +maple tree in your front lawn +it's a pruning of it and many people + + align:start position:0% +it's a pruning of it and many people + + + align:start position:0% +it's a pruning of it and many people +that keep house plants know this azaleas + + align:start position:0% +that keep house plants know this azaleas + + + align:start position:0% +that keep house plants know this azaleas +for example respond very vigorously to + + align:start position:0% +for example respond very vigorously to + + + align:start position:0% +for example respond very vigorously to +pruning + + align:start position:0% +pruning + + + align:start position:0% +pruning +so these cells that not only look like + + align:start position:0% +so these cells that not only look like + + + align:start position:0% +so these cells that not only look like +trees they also act in some ways like + + align:start position:0% +trees they also act in some ways like + + + align:start position:0% +trees they also act in some ways like +growing trees + + align:start position:0% +growing trees + + + align:start position:0% +growing trees +okay + + align:start position:0% + + + + align:start position:0% + +do people have the hand out yet for + + align:start position:0% +do people have the hand out yet for + + + align:start position:0% +do people have the hand out yet for +today + + align:start position:0% +today + + + align:start position:0% +today +you don't well it'll be coming in a + + align:start position:0% +you don't well it'll be coming in a + + + align:start position:0% +you don't well it'll be coming in a +minute + + align:start position:0% +minute + + + align:start position:0% +minute +i can i thought they would have it by + + align:start position:0% +i can i thought they would have it by + + + align:start position:0% +i can i thought they would have it by +about this time + + align:start position:0% +about this time + + + align:start position:0% +about this time +they didn't realize where i had put it + + align:start position:0% +they didn't realize where i had put it + + + align:start position:0% +they didn't realize where i had put it +on the table upstairs so they were + + align:start position:0% +on the table upstairs so they were + + + align:start position:0% +on the table upstairs so they were +looking for me instead of the handout + + align:start position:0% +looking for me instead of the handout + + + align:start position:0% +looking for me instead of the handout +and i was off doing something else + + align:start position:0% +and i was off doing something else + + + align:start position:0% +and i was off doing something else +anyway they will be in here momentarily + + align:start position:0% +anyway they will be in here momentarily + + + align:start position:0% +anyway they will be in here momentarily +we're going to start talking now about + + align:start position:0% +we're going to start talking now about + + + align:start position:0% +we're going to start talking now about +the motor system we'll do that all week + + align:start position:0% + + + + align:start position:0% + +we're going to start talking with about + + align:start position:0% +we're going to start talking with about + + + align:start position:0% +we're going to start talking with about +spinal reflexes withdrawal reflexes or + + align:start position:0% +spinal reflexes withdrawal reflexes or + + + align:start position:0% +spinal reflexes withdrawal reflexes or +the opposite + + align:start position:0% +the opposite + + + align:start position:0% +the opposite +uh of withdrawal the magnet reflex and + + align:start position:0% +uh of withdrawal the magnet reflex and + + + align:start position:0% +uh of withdrawal the magnet reflex and +the stretch reflex + + align:start position:0% +the stretch reflex + + + align:start position:0% +the stretch reflex +we'll talk a little bit during the talk + + align:start position:0% +we'll talk a little bit during the talk + + + align:start position:0% +we'll talk a little bit during the talk +of these reflexes about + + align:start position:0% +of these reflexes about + + + align:start position:0% +of these reflexes about +inter-segmental spinal organization + + align:start position:0% +inter-segmental spinal organization + + + align:start position:0% +inter-segmental spinal organization +good timing i've just started to talk + + align:start position:0% +good timing i've just started to talk + + + align:start position:0% +good timing i've just started to talk +about the motor system + + align:start position:0% + + + + align:start position:0% + +we'll say a little bit about plasticity + + align:start position:0% +we'll say a little bit about plasticity + + + align:start position:0% +we'll say a little bit about plasticity +in the spinal cord and then + + align:start position:0% +in the spinal cord and then + + + align:start position:0% +in the spinal cord and then +we're going to talk about + + align:start position:0% +we're going to talk about + + + align:start position:0% +we're going to talk about +higher systems of motor control + + align:start position:0% + + + + align:start position:0% + +because in the last on friday i would + + align:start position:0% +because in the last on friday i would + + + align:start position:0% +because in the last on friday i would +like to show you a + + align:start position:0% +like to show you a + + + align:start position:0% +like to show you a +film + + align:start position:0% +film + + + align:start position:0% +film +of a classic experiment about + + align:start position:0% +of a classic experiment about + + + align:start position:0% +of a classic experiment about +the role of descending pathways + + align:start position:0% +the role of descending pathways + + + align:start position:0% +the role of descending pathways +in primates + + align:start position:0% +in primates + + + align:start position:0% +in primates +experiments are on racist monkeys + + align:start position:0% +experiments are on racist monkeys + + + align:start position:0% +experiments are on racist monkeys +and to understand that film we have to + + align:start position:0% +and to understand that film we have to + + + align:start position:0% +and to understand that film we have to +review + + align:start position:0% +review + + + align:start position:0% +review +in a little more detail the descending + + align:start position:0% +in a little more detail the descending + + + align:start position:0% +in a little more detail the descending +pathways coming from + + align:start position:0% +pathways coming from + + + align:start position:0% +pathways coming from +behind brain midbrain and forebrain to + + align:start position:0% +behind brain midbrain and forebrain to + + + align:start position:0% +behind brain midbrain and forebrain to +the spinal cord + + align:start position:0% +the spinal cord + + + align:start position:0% +the spinal cord +and then if we have time we'll talk a + + align:start position:0% +and then if we have time we'll talk a + + + align:start position:0% +and then if we have time we'll talk a +little bit about corpus triatum and + + align:start position:0% +little bit about corpus triatum and + + + align:start position:0% +little bit about corpus triatum and +cerebellum + + align:start position:0% +cerebellum + + + align:start position:0% +cerebellum +some of the pathologies of + + align:start position:0% +some of the pathologies of + + + align:start position:0% +some of the pathologies of +striatal dysfunction and the role of the + + align:start position:0% +striatal dysfunction and the role of the + + + align:start position:0% +striatal dysfunction and the role of the +striatum and implicit learning if we + + align:start position:0% +striatum and implicit learning if we + + + align:start position:0% +striatum and implicit learning if we +don't get to that we'll do it + + align:start position:0% +don't get to that we'll do it + + + align:start position:0% +don't get to that we'll do it +after the midterm + + align:start position:0% +after the midterm + + + align:start position:0% +after the midterm +we'll just see how far we get this week + + align:start position:0% + + + + align:start position:0% + +a good place to start + + align:start position:0% +a good place to start + + + align:start position:0% +a good place to start +when you're talking about motor control + + align:start position:0% +when you're talking about motor control + + + align:start position:0% +when you're talking about motor control +is on the output side + + align:start position:0% + + + + align:start position:0% + +we could be reflexologists and assume + + align:start position:0% +we could be reflexologists and assume + + + align:start position:0% +we could be reflexologists and assume +that we should start with the sensations + + align:start position:0% +that we should start with the sensations + + + align:start position:0% +that we should start with the sensations +triggering the responses + + align:start position:0% +triggering the responses + + + align:start position:0% +triggering the responses +but i like to start with the motor + + align:start position:0% +but i like to start with the motor + + + align:start position:0% +but i like to start with the motor +system + + align:start position:0% +system + + + align:start position:0% +system +and then go backward into the cns + + align:start position:0% +and then go backward into the cns + + + align:start position:0% +and then go backward into the cns +so we're going to look at muscle + + align:start position:0% +so we're going to look at muscle + + + align:start position:0% +so we're going to look at muscle +where we find we + + align:start position:0% +where we find we + + + align:start position:0% +where we find we +magnify a little bit we'll see these + + align:start position:0% +magnify a little bit we'll see these + + + align:start position:0% +magnify a little bit we'll see these +myelinated axons of the alpha motor + + align:start position:0% +myelinated axons of the alpha motor + + + align:start position:0% +myelinated axons of the alpha motor +neurons the large motor neurons and the + + align:start position:0% +neurons the large motor neurons and the + + + align:start position:0% +neurons the large motor neurons and the +ventral horn of the spinal cord + + align:start position:0% +ventral horn of the spinal cord + + + align:start position:0% +ventral horn of the spinal cord +terminating + + align:start position:0% +terminating + + + align:start position:0% +terminating +on + + align:start position:0% +on + + + align:start position:0% +on +the muscle cells + + align:start position:0% + + + + align:start position:0% + +multinucleate cells long cells with + + align:start position:0% +multinucleate cells long cells with + + + align:start position:0% +multinucleate cells long cells with +contractile proteins + + align:start position:0% +contractile proteins + + + align:start position:0% +contractile proteins +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and then if we do a blow up of the + + align:start position:0% +and then if we do a blow up of the + + + align:start position:0% +and then if we do a blow up of the +muscle end plate + + align:start position:0% +muscle end plate + + + align:start position:0% +muscle end plate +we'll see that + + align:start position:0% +we'll see that + + + align:start position:0% +we'll see that +synaptic connections are made with a + + align:start position:0% +synaptic connections are made with a + + + align:start position:0% +synaptic connections are made with a +muscle + + align:start position:0% +muscle + + + align:start position:0% +muscle +okay at multiple points + + align:start position:0% +okay at multiple points + + + align:start position:0% +okay at multiple points +and + + align:start position:0% +and + + + align:start position:0% +and +they + + align:start position:0% +they + + + align:start position:0% +they +trigger basically an action potential in + + align:start position:0% +trigger basically an action potential in + + + align:start position:0% +trigger basically an action potential in +the muscle when that is triggered in the + + align:start position:0% +the muscle when that is triggered in the + + + align:start position:0% +the muscle when that is triggered in the +muscle the muscle contracts + + align:start position:0% +muscle the muscle contracts + + + align:start position:0% +muscle the muscle contracts +okay + + align:start position:0% + + + + align:start position:0% + +so it's similar to a neuron in some + + align:start position:0% +so it's similar to a neuron in some + + + align:start position:0% +so it's similar to a neuron in some +electrical properties but its response + + align:start position:0% +electrical properties but its response + + + align:start position:0% +electrical properties but its response +is that of contraction okay + + align:start position:0% +is that of contraction okay + + + align:start position:0% +is that of contraction okay +it doesn't communicate + + align:start position:0% +it doesn't communicate + + + align:start position:0% +it doesn't communicate +we don't have + + align:start position:0% +we don't have + + + align:start position:0% +we don't have +miod conduction that i know of there + + align:start position:0% +miod conduction that i know of there + + + align:start position:0% +miod conduction that i know of there +might be a little in smooth muscle but + + align:start position:0% +might be a little in smooth muscle but + + + align:start position:0% +might be a little in smooth muscle but +i'm not aware of it + + align:start position:0% +i'm not aware of it + + + align:start position:0% +i'm not aware of it +where muscles communicate with each + + align:start position:0% +where muscles communicate with each + + + align:start position:0% +where muscles communicate with each +other almost all the + + align:start position:0% +other almost all the + + + align:start position:0% +other almost all the +triggering of contraction is through + + align:start position:0% +triggering of contraction is through + + + align:start position:0% +triggering of contraction is through +neuronal activity + + align:start position:0% + + + + align:start position:0% + +so if we start with the reflex model + + align:start position:0% +so if we start with the reflex model + + + align:start position:0% +so if we start with the reflex model +remember reflexology was the idea that + + align:start position:0% +remember reflexology was the idea that + + + align:start position:0% +remember reflexology was the idea that +all behavior can be explained in terms + + align:start position:0% +all behavior can be explained in terms + + + align:start position:0% +all behavior can be explained in terms +of + + align:start position:0% +of + + + align:start position:0% +of +s2r processing + + align:start position:0% +s2r processing + + + align:start position:0% +s2r processing +everything was a reflex a simple reflex + + align:start position:0% +everything was a reflex a simple reflex + + + align:start position:0% +everything was a reflex a simple reflex +or more complex reflex + + align:start position:0% + + + + align:start position:0% + +almost everything that pavlov wrote + + align:start position:0% +almost everything that pavlov wrote + + + align:start position:0% +almost everything that pavlov wrote +about motor control was put in those + + align:start position:0% +about motor control was put in those + + + align:start position:0% +about motor control was put in those +terms + + align:start position:0% +terms + + + align:start position:0% +terms +and uh both pavlov and then laters + + align:start position:0% +and uh both pavlov and then laters + + + align:start position:0% +and uh both pavlov and then laters +skinner and others thorndike preceding + + align:start position:0% +skinner and others thorndike preceding + + + align:start position:0% +skinner and others thorndike preceding +him + + align:start position:0% +him + + + align:start position:0% +him +realized that + + align:start position:0% +realized that + + + align:start position:0% +realized that +sr pathways could be plastic you can get + + align:start position:0% +sr pathways could be plastic you can get + + + align:start position:0% +sr pathways could be plastic you can get +conditioning learning pavlov talked + + align:start position:0% +conditioning learning pavlov talked + + + align:start position:0% +conditioning learning pavlov talked +about + + align:start position:0% +about + + + align:start position:0% +about +classical conditioning or pavlovian + + align:start position:0% +classical conditioning or pavlovian + + + align:start position:0% +classical conditioning or pavlovian +conditioning + + align:start position:0% + + + + align:start position:0% + +skinner talked about instrumental + + align:start position:0% +skinner talked about instrumental + + + align:start position:0% +skinner talked about instrumental +conditioning like an animal solving a + + align:start position:0% +conditioning like an animal solving a + + + align:start position:0% +conditioning like an animal solving a +problem box when he solves it randomly + + align:start position:0% +problem box when he solves it randomly + + + align:start position:0% +problem box when he solves it randomly +at first he will then learn and + + align:start position:0% +at first he will then learn and + + + align:start position:0% +at first he will then learn and +repeat the moves that were rewarding + + align:start position:0% + + + + align:start position:0% + +but they still stuck to the sr model + + align:start position:0% +but they still stuck to the sr model + + + align:start position:0% +but they still stuck to the sr model +now we know and i've mentioned in the + + align:start position:0% +now we know and i've mentioned in the + + + align:start position:0% +now we know and i've mentioned in the +introductory lectures that the circuitry + + align:start position:0% +introductory lectures that the circuitry + + + align:start position:0% +introductory lectures that the circuitry +and individual cells are more complex + + align:start position:0% +and individual cells are more complex + + + align:start position:0% +and individual cells are more complex +they have feedback they have endogenous + + align:start position:0% +they have feedback they have endogenous + + + align:start position:0% +they have feedback they have endogenous +activity they have modulation whether + + align:start position:0% +activity they have modulation whether + + + align:start position:0% +activity they have modulation whether +by other pathways + + align:start position:0% +by other pathways + + + align:start position:0% +by other pathways +that makes the sr model a little bit + + align:start position:0% +that makes the sr model a little bit + + + align:start position:0% +that makes the sr model a little bit +difficult to stick to but + + align:start position:0% +difficult to stick to but + + + align:start position:0% +difficult to stick to but +if you're dealing with an a sim animal + + align:start position:0% +if you're dealing with an a sim animal + + + align:start position:0% +if you're dealing with an a sim animal +like a spinal animal you've removed the + + align:start position:0% +like a spinal animal you've removed the + + + align:start position:0% +like a spinal animal you've removed the +brain + + align:start position:0% +brain + + + align:start position:0% +brain +as it was done by sharington in his + + align:start position:0% +as it was done by sharington in his + + + align:start position:0% +as it was done by sharington in his +early studies + + align:start position:0% +early studies + + + align:start position:0% +early studies +in + + align:start position:0% +in + + + align:start position:0% +in +around 1900 + + align:start position:0% +around 1900 + + + align:start position:0% +around 1900 +it works very well and you can explain + + align:start position:0% +it works very well and you can explain + + + align:start position:0% +it works very well and you can explain +most of the behavior that you can get + + align:start position:0% +most of the behavior that you can get + + + align:start position:0% +most of the behavior that you can get +and you'd say well what behavior can you + + align:start position:0% +and you'd say well what behavior can you + + + align:start position:0% +and you'd say well what behavior can you +get out of the spinal animal well quite + + align:start position:0% +get out of the spinal animal well quite + + + align:start position:0% +get out of the spinal animal well quite +a bit actually + + align:start position:0% +a bit actually + + + align:start position:0% +a bit actually +okay + + align:start position:0% +okay + + + align:start position:0% +okay +the spinal cord can do a lot by itself + + align:start position:0% + + + + align:start position:0% + +why can't we see that in humans with + + align:start position:0% +why can't we see that in humans with + + + align:start position:0% +why can't we see that in humans with +spinal transaction why don't we see more + + align:start position:0% +spinal transaction why don't we see more + + + align:start position:0% +spinal transaction why don't we see more +behavior why do they seem so incredibly + + align:start position:0% +behavior why do they seem so incredibly + + + align:start position:0% +behavior why do they seem so incredibly +paralyzed + + align:start position:0% + + + + align:start position:0% + +remember spinal shock + + align:start position:0% +remember spinal shock + + + align:start position:0% +remember spinal shock +and diastasis when you have a huge + + align:start position:0% +and diastasis when you have a huge + + + align:start position:0% +and diastasis when you have a huge +number of excitatory connections removed + + align:start position:0% +number of excitatory connections removed + + + align:start position:0% +number of excitatory connections removed +as in humans with a very large forebrain + + align:start position:0% +as in humans with a very large forebrain + + + align:start position:0% +as in humans with a very large forebrain +it's very difficult to get normal spinal + + align:start position:0% +it's very difficult to get normal spinal + + + align:start position:0% +it's very difficult to get normal spinal +function it's easier in animals with a + + align:start position:0% +function it's easier in animals with a + + + align:start position:0% +function it's easier in animals with a +smaller forebrain + + align:start position:0% + + + + align:start position:0% + +but still even with + + align:start position:0% +but still even with + + + align:start position:0% +but still even with +humans with spinal transection + + align:start position:0% +humans with spinal transection + + + align:start position:0% +humans with spinal transection +they can learn to use spinal reflexes + + align:start position:0% + + + + align:start position:0% + +for a number of functions + + align:start position:0% + + + + align:start position:0% + +so we're going to now talk about two + + align:start position:0% +so we're going to now talk about two + + + align:start position:0% +so we're going to now talk about two +basic responses simple escape or + + align:start position:0% +basic responses simple escape or + + + align:start position:0% +basic responses simple escape or +avoidance responses and approach or + + align:start position:0% +avoidance responses and approach or + + + align:start position:0% +avoidance responses and approach or +grasping responses + + align:start position:0% + + + + align:start position:0% + +we'll start with the withdrawal reflex + + align:start position:0% +we'll start with the withdrawal reflex + + + align:start position:0% +we'll start with the withdrawal reflex +it's a cutaneous reflex + + align:start position:0% +it's a cutaneous reflex + + + align:start position:0% +it's a cutaneous reflex +it's a flexion reflex always involving + + align:start position:0% +it's a flexion reflex always involving + + + align:start position:0% +it's a flexion reflex always involving +at least two synapses + + align:start position:0% +at least two synapses + + + align:start position:0% +at least two synapses +and i want to ask here at the beginning + + align:start position:0% +and i want to ask here at the beginning + + + align:start position:0% +and i want to ask here at the beginning +well how do you know + + align:start position:0% +well how do you know + + + align:start position:0% +well how do you know +it's not monosynaptic + + align:start position:0% + + + + align:start position:0% + +we'll go through + + align:start position:0% +we'll go through + + + align:start position:0% +we'll go through +some early studies that demonstrated + + align:start position:0% +some early studies that demonstrated + + + align:start position:0% +some early studies that demonstrated +that it involved more than one synapse + + align:start position:0% +that it involved more than one synapse + + + align:start position:0% +that it involved more than one synapse +and these were studies + + align:start position:0% +and these were studies + + + align:start position:0% +and these were studies +that were done by physiological means + + align:start position:0% +that were done by physiological means + + + align:start position:0% +that were done by physiological means +with some knowledge of the anatomy + + align:start position:0% +with some knowledge of the anatomy + + + align:start position:0% +with some knowledge of the anatomy +they had the knowledge of kahal to do + + align:start position:0% +they had the knowledge of kahal to do + + + align:start position:0% +they had the knowledge of kahal to do +these + + align:start position:0% +these + + + align:start position:0% +these +but after we do that then we'll talk + + align:start position:0% +but after we do that then we'll talk + + + align:start position:0% +but after we do that then we'll talk +about + + align:start position:0% +about + + + align:start position:0% +about +we'll mention + + align:start position:0% + + + + align:start position:0% + +similar + + align:start position:0% +similar + + + align:start position:0% +similar +responses and other modalities + + align:start position:0% +responses and other modalities + + + align:start position:0% +responses and other modalities +i'll talk about the magnet reflex which + + align:start position:0% +i'll talk about the magnet reflex which + + + align:start position:0% +i'll talk about the magnet reflex which +is the opposite + + align:start position:0% +is the opposite + + + align:start position:0% +is the opposite +something you see more in babies than + + align:start position:0% +something you see more in babies than + + + align:start position:0% +something you see more in babies than +adults + + align:start position:0% +adults + + + align:start position:0% +adults +will mention examples of higher + + align:start position:0% +will mention examples of higher + + + align:start position:0% +will mention examples of higher +influences on the spinal mechanisms and + + align:start position:0% +influences on the spinal mechanisms and + + + align:start position:0% +influences on the spinal mechanisms and +effects of novelty + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so first of all cutaneous reflex called + + align:start position:0% +so first of all cutaneous reflex called + + + align:start position:0% +so first of all cutaneous reflex called +the withdrawal reflex + + align:start position:0% + + + + align:start position:0% + +how do you trigger it + + align:start position:0% + + + + align:start position:0% + +well a painful stimulus is the best way + + align:start position:0% +well a painful stimulus is the best way + + + align:start position:0% +well a painful stimulus is the best way +okay + + align:start position:0% + + + + align:start position:0% + +if we're operating on an animal and we + + align:start position:0% +if we're operating on an animal and we + + + align:start position:0% +if we're operating on an animal and we +want to be sure he's fully anesthetized + + align:start position:0% +want to be sure he's fully anesthetized + + + align:start position:0% +want to be sure he's fully anesthetized +we test it by pinching usually between + + align:start position:0% +we test it by pinching usually between + + + align:start position:0% +we test it by pinching usually between +the digits + + align:start position:0% +the digits + + + align:start position:0% +the digits +if you pinch yourself you'll feel pain + + align:start position:0% +if you pinch yourself you'll feel pain + + + align:start position:0% +if you pinch yourself you'll feel pain +but you probably won't withdraw because + + align:start position:0% +but you probably won't withdraw because + + + align:start position:0% +but you probably won't withdraw because +you're voluntarily + + align:start position:0% +you're voluntarily + + + align:start position:0% +you're voluntarily +you know reducing that but if you do it + + align:start position:0% +you know reducing that but if you do it + + + align:start position:0% +you know reducing that but if you do it +to your friend + + align:start position:0% +to your friend + + + align:start position:0% +to your friend +you know he's much more likely if you + + align:start position:0% +you know he's much more likely if you + + + align:start position:0% +you know he's much more likely if you +suddenly pinch him to pull back + + align:start position:0% +suddenly pinch him to pull back + + + align:start position:0% +suddenly pinch him to pull back +involuntarily + + align:start position:0% +involuntarily + + + align:start position:0% +involuntarily +he thinks he's doing it on purpose but + + align:start position:0% +he thinks he's doing it on purpose but + + + align:start position:0% +he thinks he's doing it on purpose but +in fact it's an involuntary reaction + + align:start position:0% +in fact it's an involuntary reaction + + + align:start position:0% +in fact it's an involuntary reaction +you remember the picture from + + align:start position:0% +you remember the picture from + + + align:start position:0% +you remember the picture from +descartes of the naked boy sticking his + + align:start position:0% +descartes of the naked boy sticking his + + + align:start position:0% +descartes of the naked boy sticking his +foot in the fire okay + + align:start position:0% + + + + align:start position:0% + +triggering the withdrawal reflex because + + align:start position:0% +triggering the withdrawal reflex because + + + align:start position:0% +triggering the withdrawal reflex because +that's a reflex that descartes + + align:start position:0% + + + + align:start position:0% + +spurred descartes to start thinking in + + align:start position:0% +spurred descartes to start thinking in + + + align:start position:0% +spurred descartes to start thinking in +terms of nervous pathways and + + align:start position:0% +terms of nervous pathways and + + + align:start position:0% +terms of nervous pathways and +connections through the brain + + align:start position:0% + + + + align:start position:0% + +let's first talk about the + + align:start position:0% +let's first talk about the + + + align:start position:0% +let's first talk about the +effects of the intensity stimulation and + + align:start position:0% +effects of the intensity stimulation and + + + align:start position:0% +effects of the intensity stimulation and +how the effect spreads within the cord + + align:start position:0% +how the effect spreads within the cord + + + align:start position:0% +how the effect spreads within the cord +i'm going to + + align:start position:0% + + + + align:start position:0% + +let's take a spinal cord and look at a + + align:start position:0% +let's take a spinal cord and look at a + + + align:start position:0% +let's take a spinal cord and look at a +top view like that + + align:start position:0% +top view like that + + + align:start position:0% +top view like that +and take + + align:start position:0% +and take + + + align:start position:0% +and take +one dorsal root okay + + align:start position:0% + + + + align:start position:0% + +and here would be the dorsal root + + align:start position:0% +and here would be the dorsal root + + + align:start position:0% +and here would be the dorsal root +ganglion there would be many cell bodies + + align:start position:0% +ganglion there would be many cell bodies + + + align:start position:0% +ganglion there would be many cell bodies +there we're going to let that represent + + align:start position:0% +there we're going to let that represent + + + align:start position:0% +there we're going to let that represent +a series of axons okay + + align:start position:0% +a series of axons okay + + + align:start position:0% +a series of axons okay +sensory accidents coming into the cord + + align:start position:0% +sensory accidents coming into the cord + + + align:start position:0% +sensory accidents coming into the cord +beginning say in the foot + + align:start position:0% +beginning say in the foot + + + align:start position:0% +beginning say in the foot +okay now that comes in the accents + + align:start position:0% +okay now that comes in the accents + + + align:start position:0% +okay now that comes in the accents +actually spread up and down the cord + + align:start position:0% + + + + align:start position:0% + +and if we let + + align:start position:0% +and if we let + + + align:start position:0% +and if we let +it will show that termination + + align:start position:0% +it will show that termination + + + align:start position:0% +it will show that termination +what i want to show here is that the + + align:start position:0% +what i want to show here is that the + + + align:start position:0% +what i want to show here is that the +termination is most dense + + align:start position:0% +termination is most dense + + + align:start position:0% +termination is most dense +right in the area of entry + + align:start position:0% +right in the area of entry + + + align:start position:0% +right in the area of entry +and it becomes less and less dense when + + align:start position:0% +and it becomes less and less dense when + + + align:start position:0% +and it becomes less and less dense when +you get further from it + + align:start position:0% +you get further from it + + + align:start position:0% +you get further from it +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now the result of that + + align:start position:0% + + + + align:start position:0% + +is that + + align:start position:0% +is that + + + align:start position:0% +is that +with a stimulus that's not very intense + + align:start position:0% +with a stimulus that's not very intense + + + align:start position:0% +with a stimulus that's not very intense +we might activate cells bring them above + + align:start position:0% +we might activate cells bring them above + + + align:start position:0% +we might activate cells bring them above +threshold only in that region + + align:start position:0% +threshold only in that region + + + align:start position:0% +threshold only in that region +okay because there's not enough spatial + + align:start position:0% +okay because there's not enough spatial + + + align:start position:0% +okay because there's not enough spatial +summation + + align:start position:0% +summation + + + align:start position:0% +summation +when we get further from the point of + + align:start position:0% +when we get further from the point of + + + align:start position:0% +when we get further from the point of +entry + + align:start position:0% + + + + align:start position:0% + +so what could happen then is that cells + + align:start position:0% +so what could happen then is that cells + + + align:start position:0% +so what could happen then is that cells +in this region + + align:start position:0% +in this region + + + align:start position:0% +in this region +could result + + align:start position:0% +could result + + + align:start position:0% +could result +could conduct action potentials + + align:start position:0% +could conduct action potentials + + + align:start position:0% +could conduct action potentials +and reach motor neurons + + align:start position:0% +and reach motor neurons + + + align:start position:0% +and reach motor neurons +which then could go out and give the + + align:start position:0% +which then could go out and give the + + + align:start position:0% +which then could go out and give the +reflex + + align:start position:0% +reflex + + + align:start position:0% +reflex +okay + + align:start position:0% + + + + align:start position:0% + +now + + align:start position:0% +now + + + align:start position:0% +now +with more intense stimulation + + align:start position:0% +with more intense stimulation + + + align:start position:0% +with more intense stimulation +what will happen is it will spread over + + align:start position:0% +what will happen is it will spread over + + + align:start position:0% +what will happen is it will spread over +a wider region + + align:start position:0% +a wider region + + + align:start position:0% +a wider region +you will reach threshold over wider + + align:start position:0% +you will reach threshold over wider + + + align:start position:0% +you will reach threshold over wider +region because with more intense + + align:start position:0% +region because with more intense + + + align:start position:0% +region because with more intense +stimulation you + + align:start position:0% +stimulation you + + + align:start position:0% +stimulation you +now you have more temporal summation + + align:start position:0% + + + + align:start position:0% + +you'll activate cells over + + align:start position:0% +you'll activate cells over + + + align:start position:0% +you'll activate cells over +this entire region + + align:start position:0% + + + + align:start position:0% + +so you get a spread + + align:start position:0% +so you get a spread + + + align:start position:0% +so you get a spread +of effect + + align:start position:0% +of effect + + + align:start position:0% +of effect +but in every case even with the low + + align:start position:0% +but in every case even with the low + + + align:start position:0% +but in every case even with the low +intensity stimulation + + align:start position:0% +intensity stimulation + + + align:start position:0% +intensity stimulation +you are still + + align:start position:0% + + + + align:start position:0% + +you are still activating this entire + + align:start position:0% +you are still activating this entire + + + align:start position:0% +you are still activating this entire +axonal tree + + align:start position:0% +axonal tree + + + align:start position:0% +axonal tree +so what about + + align:start position:0% +so what about + + + align:start position:0% +so what about +out here with the low intensities of + + align:start position:0% +out here with the low intensities of + + + align:start position:0% +out here with the low intensities of +stimulation + + align:start position:0% +stimulation + + + align:start position:0% +stimulation +it's only the most intense stimulation + + align:start position:0% +it's only the most intense stimulation + + + align:start position:0% +it's only the most intense stimulation +that was going to activate that fringe + + align:start position:0% +that was going to activate that fringe + + + align:start position:0% +that was going to activate that fringe +of the distribution pattern of the axons + + align:start position:0% +of the distribution pattern of the axons + + + align:start position:0% +of the distribution pattern of the axons +so the physiologist called that the + + align:start position:0% +so the physiologist called that the + + + align:start position:0% +so the physiologist called that the +subliminal fringe + + align:start position:0% +subliminal fringe + + + align:start position:0% +subliminal fringe +because the stimulation there was + + align:start position:0% +because the stimulation there was + + + align:start position:0% +because the stimulation there was +usually + + align:start position:0% +usually + + + align:start position:0% +usually +below the lehman lehman means threshold + + align:start position:0% +below the lehman lehman means threshold + + + align:start position:0% +below the lehman lehman means threshold +so subliminal + + align:start position:0% +so subliminal + + + align:start position:0% +so subliminal +means below the threshold + + align:start position:0% +means below the threshold + + + align:start position:0% +means below the threshold +you've probably heard about studies of + + align:start position:0% +you've probably heard about studies of + + + align:start position:0% +you've probably heard about studies of +subliminal perception things you don't + + align:start position:0% +subliminal perception things you don't + + + align:start position:0% +subliminal perception things you don't +notice but are still getting into your + + align:start position:0% +notice but are still getting into your + + + align:start position:0% +notice but are still getting into your +nervous system + + align:start position:0% +nervous system + + + align:start position:0% +nervous system +okay but that was + + align:start position:0% +okay but that was + + + align:start position:0% +okay but that was +taken from this idea + + align:start position:0% + + + + align:start position:0% + +why is that important + + align:start position:0% +why is that important + + + align:start position:0% +why is that important +why is the subliminal fringe important + + align:start position:0% +why is the subliminal fringe important + + + align:start position:0% +why is the subliminal fringe important +well + + align:start position:0% +well + + + align:start position:0% +well +let's put in blue here + + align:start position:0% +let's put in blue here + + + align:start position:0% +let's put in blue here +descending pathways coming from the + + align:start position:0% +descending pathways coming from the + + + align:start position:0% +descending pathways coming from the +brain + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and have whoops supposed to be blue here + + align:start position:0% + + + + align:start position:0% + +and so here's + + align:start position:0% + + + + align:start position:0% + +here's the axons coming in + + align:start position:0% + + + + align:start position:0% + +and let's say its main distribution is + + align:start position:0% +and let's say its main distribution is + + + align:start position:0% +and let's say its main distribution is +up here + + align:start position:0% +up here + + + align:start position:0% +up here +many terminations up here + + align:start position:0% +many terminations up here + + + align:start position:0% +many terminations up here +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now the descending input + + align:start position:0% +now the descending input + + + align:start position:0% +now the descending input +might not be intense enough to trigger + + align:start position:0% +might not be intense enough to trigger + + + align:start position:0% +might not be intense enough to trigger +the cells there + + align:start position:0% +the cells there + + + align:start position:0% +the cells there +and the sensory input coming from the + + align:start position:0% +and the sensory input coming from the + + + align:start position:0% +and the sensory input coming from the +stimulus here might also not be intense + + align:start position:0% +stimulus here might also not be intense + + + align:start position:0% +stimulus here might also not be intense +enough but the two together + + align:start position:0% +enough but the two together + + + align:start position:0% +enough but the two together +might be enough + + align:start position:0% +might be enough + + + align:start position:0% +might be enough +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so you might activate + + align:start position:0% +so you might activate + + + align:start position:0% +so you might activate +okay this region of the cord + + align:start position:0% +okay this region of the cord + + + align:start position:0% +okay this region of the cord +only with converging input from coming + + align:start position:0% +only with converging input from coming + + + align:start position:0% +only with converging input from coming +from the brain and coming from the + + align:start position:0% +from the brain and coming from the + + + align:start position:0% +from the brain and coming from the +sensory input + + align:start position:0% +sensory input + + + align:start position:0% +sensory input +coming into the cord + + align:start position:0% +coming into the cord + + + align:start position:0% +coming into the cord +that's why this limbo area is so + + align:start position:0% +that's why this limbo area is so + + + align:start position:0% +that's why this limbo area is so +important + + align:start position:0% + + + + align:start position:0% + +okay now let's go to this question of + + align:start position:0% +okay now let's go to this question of + + + align:start position:0% +okay now let's go to this question of +how what it was shown by the early + + align:start position:0% +how what it was shown by the early + + + align:start position:0% +how what it was shown by the early +physiologists that the reflex is not + + align:start position:0% +physiologists that the reflex is not + + + align:start position:0% +physiologists that the reflex is not +monosynaptic + + align:start position:0% +monosynaptic + + + align:start position:0% +monosynaptic +and their experiments also gave the + + align:start position:0% +and their experiments also gave the + + + align:start position:0% +and their experiments also gave the +first measure + + align:start position:0% +first measure + + + align:start position:0% +first measure +of synaptic delay + + align:start position:0% +of synaptic delay + + + align:start position:0% +of synaptic delay +synaptic delay means the time it takes + + align:start position:0% +synaptic delay means the time it takes + + + align:start position:0% +synaptic delay means the time it takes +for + + align:start position:0% +for + + + align:start position:0% +for +activation on the presynaptic side + + align:start position:0% +activation on the presynaptic side + + + align:start position:0% +activation on the presynaptic side +to reach the postsynaptic side + + align:start position:0% +to reach the postsynaptic side + + + align:start position:0% +to reach the postsynaptic side +why does it take time + + align:start position:0% + + + + align:start position:0% + +well + + align:start position:0% +well + + + align:start position:0% +well +it doesn't take any time if the stimulus + + align:start position:0% +it doesn't take any time if the stimulus + + + align:start position:0% +it doesn't take any time if the stimulus +is electrical but in almost all synapses + + align:start position:0% +is electrical but in almost all synapses + + + align:start position:0% +is electrical but in almost all synapses +in the cns are chemical and it takes + + align:start position:0% +in the cns are chemical and it takes + + + align:start position:0% +in the cns are chemical and it takes +time for molecules to diffuse across the + + align:start position:0% +time for molecules to diffuse across the + + + align:start position:0% +time for molecules to diffuse across the +synaptic clef bind to the + + align:start position:0% +synaptic clef bind to the + + + align:start position:0% +synaptic clef bind to the +uh + + align:start position:0% +uh + + + align:start position:0% +uh +receptor molecules there and activate + + align:start position:0% +receptor molecules there and activate + + + align:start position:0% +receptor molecules there and activate +the cell + + align:start position:0% +the cell + + + align:start position:0% +the cell +okay + + align:start position:0% + + + + align:start position:0% + +so let's go through the steps + + align:start position:0% +so let's go through the steps + + + align:start position:0% +so let's go through the steps +they begin + + align:start position:0% +they begin + + + align:start position:0% +they begin +by recording from a ventral root so look + + align:start position:0% +by recording from a ventral root so look + + + align:start position:0% +by recording from a ventral root so look +at this picture first + + align:start position:0% + + + + align:start position:0% + +okay and here's + + align:start position:0% +okay and here's + + + align:start position:0% +okay and here's +a recording device attached to the + + align:start position:0% +a recording device attached to the + + + align:start position:0% +a recording device attached to the +ventral root and notice this is the way + + align:start position:0% +ventral root and notice this is the way + + + align:start position:0% +ventral root and notice this is the way +the experiment was done + + align:start position:0% +the experiment was done + + + align:start position:0% +the experiment was done +uh + + align:start position:0% +uh + + + align:start position:0% +uh +i need my pointer so + + align:start position:0% + + + + align:start position:0% + +they generally crush the nerve here + + align:start position:0% +they generally crush the nerve here + + + align:start position:0% +they generally crush the nerve here +because they didn't want to activate + + align:start position:0% +because they didn't want to activate + + + align:start position:0% +because they didn't want to activate +anything in the periphery here + + align:start position:0% +anything in the periphery here + + + align:start position:0% +anything in the periphery here +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so they're recording there + + align:start position:0% +so they're recording there + + + align:start position:0% +so they're recording there +and the first place they stimulated + + align:start position:0% +and the first place they stimulated + + + align:start position:0% +and the first place they stimulated +is labeled two here the little pipette + + align:start position:0% +is labeled two here the little pipette + + + align:start position:0% +is labeled two here the little pipette +here + + align:start position:0% +here + + + align:start position:0% +here +going right into + + align:start position:0% +going right into + + + align:start position:0% +going right into +the region of motor neurons + + align:start position:0% +the region of motor neurons + + + align:start position:0% +the region of motor neurons +in the ventral horn okay + + align:start position:0% + + + + align:start position:0% + +so that's described here you record from + + align:start position:0% +so that's described here you record from + + + align:start position:0% +so that's described here you record from +the ventral root you stimulate the motor + + align:start position:0% +the ventral root you stimulate the motor + + + align:start position:0% +the ventral root you stimulate the motor +neurons and of course you then record a + + align:start position:0% +neurons and of course you then record a + + + align:start position:0% +neurons and of course you then record a +valley of action potentials after a + + align:start position:0% +valley of action potentials after a + + + align:start position:0% +valley of action potentials after a +brief conduction delay and i show that + + align:start position:0% +brief conduction delay and i show that + + + align:start position:0% +brief conduction delay and i show that +in the graph here okay + + align:start position:0% +in the graph here okay + + + align:start position:0% +in the graph here okay +you stimulate + + align:start position:0% +you stimulate + + + align:start position:0% +you stimulate +and after a brief delay + + align:start position:0% +and after a brief delay + + + align:start position:0% +and after a brief delay +shown by the + + align:start position:0% +shown by the + + + align:start position:0% +shown by the +two lines there + + align:start position:0% +two lines there + + + align:start position:0% +two lines there +you can record a volume of action + + align:start position:0% +you can record a volume of action + + + align:start position:0% +you can record a volume of action +potential or you could if you had it + + align:start position:0% +potential or you could if you had it + + + align:start position:0% +potential or you could if you had it +connected to the muscles you could + + align:start position:0% +connected to the muscles you could + + + align:start position:0% +connected to the muscles you could +record the muscle twitch but we don't + + align:start position:0% +record the muscle twitch but we don't + + + align:start position:0% +record the muscle twitch but we don't +want + + align:start position:0% +want + + + align:start position:0% +want +the muscle twitch because we don't want + + align:start position:0% +the muscle twitch because we don't want + + + align:start position:0% +the muscle twitch because we don't want +to affect sensory inputs here at all so + + align:start position:0% +to affect sensory inputs here at all so + + + align:start position:0% +to affect sensory inputs here at all so +we're that's why we crush the root okay + + align:start position:0% + + + + align:start position:0% + +so that was the first + + align:start position:0% +so that was the first + + + align:start position:0% +so that was the first +experiment now + + align:start position:0% +experiment now + + + align:start position:0% +experiment now +this is what renshaw did + + align:start position:0% +this is what renshaw did + + + align:start position:0% +this is what renshaw did +he pulled that electrode back + + align:start position:0% +he pulled that electrode back + + + align:start position:0% +he pulled that electrode back +until he was no longer stimulating motor + + align:start position:0% +until he was no longer stimulating motor + + + align:start position:0% +until he was no longer stimulating motor +neurons directly + + align:start position:0% +neurons directly + + + align:start position:0% +neurons directly +he was stimulating interneuron + + align:start position:0% +he was stimulating interneuron + + + align:start position:0% +he was stimulating interneuron +interneurons though that contacted motor + + align:start position:0% +interneurons though that contacted motor + + + align:start position:0% +interneurons though that contacted motor +neurons and he knew all this you could + + align:start position:0% +neurons and he knew all this you could + + + align:start position:0% +neurons and he knew all this you could +guess that from the work of kahal + + align:start position:0% +guess that from the work of kahal + + + align:start position:0% +guess that from the work of kahal +okay + + align:start position:0% + + + + align:start position:0% + +but in his recordings he could see that + + align:start position:0% +but in his recordings he could see that + + + align:start position:0% +but in his recordings he could see that +that initial volley suddenly went away + + align:start position:0% +that initial volley suddenly went away + + + align:start position:0% +that initial volley suddenly went away +when he pulled the electrode back a + + align:start position:0% +when he pulled the electrode back a + + + align:start position:0% +when he pulled the electrode back a +certain distance okay and then if he's + + align:start position:0% +certain distance okay and then if he's + + + align:start position:0% +certain distance okay and then if he's +stimulated with the lower intensities + + align:start position:0% +stimulated with the lower intensities + + + align:start position:0% +stimulated with the lower intensities +shown in the solid line there + + align:start position:0% +shown in the solid line there + + + align:start position:0% +shown in the solid line there +he got a volley + + align:start position:0% + + + + align:start position:0% + +but it was after a delay the delay was + + align:start position:0% +but it was after a delay the delay was + + + align:start position:0% +but it was after a delay the delay was +0.5 to 0.7 milliseconds + + align:start position:0% +0.5 to 0.7 milliseconds + + + align:start position:0% +0.5 to 0.7 milliseconds +and if you raise the intensity + + align:start position:0% +and if you raise the intensity + + + align:start position:0% +and if you raise the intensity +okay + + align:start position:0% +okay + + + align:start position:0% +okay +it would become larger + + align:start position:0% +it would become larger + + + align:start position:0% +it would become larger +if you raised it enough you would start + + align:start position:0% +if you raised it enough you would start + + + align:start position:0% +if you raised it enough you would start +getting something like this initial one + + align:start position:0% +getting something like this initial one + + + align:start position:0% +getting something like this initial one +followed by the later one + + align:start position:0% +followed by the later one + + + align:start position:0% +followed by the later one +indicating to him that he was the + + align:start position:0% +indicating to him that he was the + + + align:start position:0% +indicating to him that he was the +current head spread with the higher + + align:start position:0% +current head spread with the higher + + + align:start position:0% +current head spread with the higher +intensities to directly stimulate motor + + align:start position:0% +intensities to directly stimulate motor + + + align:start position:0% +intensities to directly stimulate motor +neurons but was still stimulating + + align:start position:0% +neurons but was still stimulating + + + align:start position:0% +neurons but was still stimulating +interneurons + + align:start position:0% +interneurons + + + align:start position:0% +interneurons +which required one synapse to reach the + + align:start position:0% +which required one synapse to reach the + + + align:start position:0% +which required one synapse to reach the +motor + + align:start position:0% +motor + + + align:start position:0% +motor +neuron so this was the first measure of + + align:start position:0% +neuron so this was the first measure of + + + align:start position:0% +neuron so this was the first measure of +synaptic delay + + align:start position:0% +synaptic delay + + + align:start position:0% +synaptic delay +okay + + align:start position:0% + + + + align:start position:0% + +lloyd then did + + align:start position:0% +lloyd then did + + + align:start position:0% +lloyd then did +a further experiment using the same + + align:start position:0% +a further experiment using the same + + + align:start position:0% +a further experiment using the same +paradigm + + align:start position:0% +paradigm + + + align:start position:0% +paradigm +he moved his electrodes with the same + + align:start position:0% +he moved his electrodes with the same + + + align:start position:0% +he moved his electrodes with the same +set up here to the dorsal root + + align:start position:0% +set up here to the dorsal root + + + align:start position:0% +set up here to the dorsal root +and if he stimulates + + align:start position:0% +and if he stimulates + + + align:start position:0% +and if he stimulates +with a intense enough stimulation he's + + align:start position:0% +with a intense enough stimulation he's + + + align:start position:0% +with a intense enough stimulation he's +going to activate all the fibers if he + + align:start position:0% +going to activate all the fibers if he + + + align:start position:0% +going to activate all the fibers if he +stimulates with a milder stimulation he + + align:start position:0% +stimulates with a milder stimulation he + + + align:start position:0% +stimulates with a milder stimulation he +will activate only the large fibers + + align:start position:0% +will activate only the large fibers + + + align:start position:0% +will activate only the large fibers +okay the largest fibers in the dorsal + + align:start position:0% +okay the largest fibers in the dorsal + + + align:start position:0% +okay the largest fibers in the dorsal +root + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and again the intensity was varied + + align:start position:0% +and again the intensity was varied + + + align:start position:0% +and again the intensity was varied +and what he found was he got something + + align:start position:0% +and what he found was he got something + + + align:start position:0% +and what he found was he got something +similar + + align:start position:0% +similar + + + align:start position:0% +similar +to what rancho had gotten stimulating + + align:start position:0% +to what rancho had gotten stimulating + + + align:start position:0% +to what rancho had gotten stimulating +the internal pool on the cord he got our + + align:start position:0% +the internal pool on the cord he got our + + + align:start position:0% +the internal pool on the cord he got our +first volley + + align:start position:0% +first volley + + + align:start position:0% +first volley +but then he also got later + + align:start position:0% +but then he also got later + + + align:start position:0% +but then he also got later +volleys and as he raised the intensity + + align:start position:0% +volleys and as he raised the intensity + + + align:start position:0% +volleys and as he raised the intensity +he got + + align:start position:0% +he got + + + align:start position:0% +he got +additional he got greater + + align:start position:0% +additional he got greater + + + align:start position:0% +additional he got greater +amount of number of action potentials + + align:start position:0% +amount of number of action potentials + + + align:start position:0% +amount of number of action potentials +more action potentials appearing in the + + align:start position:0% +more action potentials appearing in the + + + align:start position:0% +more action potentials appearing in the +ventral root + + align:start position:0% +ventral root + + + align:start position:0% +ventral root +and they appeared to be sort of harmonic + + align:start position:0% +and they appeared to be sort of harmonic + + + align:start position:0% +and they appeared to be sort of harmonic +spaced + + align:start position:0% +spaced + + + align:start position:0% +spaced +similar + + align:start position:0% +similar + + + align:start position:0% +similar +at + + align:start position:0% +at + + + align:start position:0% +at +distances that indicated that it was + + align:start position:0% +distances that indicated that it was + + + align:start position:0% +distances that indicated that it was +simply + + align:start position:0% + + + + align:start position:0% + +one synapse two synapses three synapses + + align:start position:0% +one synapse two synapses three synapses + + + align:start position:0% +one synapse two synapses three synapses +and so forth + + align:start position:0% +and so forth + + + align:start position:0% +and so forth +okay he never got the artifact here + + align:start position:0% +okay he never got the artifact here + + + align:start position:0% +okay he never got the artifact here +because now his electorate was outside + + align:start position:0% +because now his electorate was outside + + + align:start position:0% +because now his electorate was outside +the spinal cord so it wasn't spreading + + align:start position:0% +the spinal cord so it wasn't spreading + + + align:start position:0% +the spinal cord so it wasn't spreading +to motor neurons now + + align:start position:0% +to motor neurons now + + + align:start position:0% +to motor neurons now +that's why he didn't get that artifact + + align:start position:0% +that's why he didn't get that artifact + + + align:start position:0% +that's why he didn't get that artifact +that + + align:start position:0% +that + + + align:start position:0% +that +rancho got here + + align:start position:0% +rancho got here + + + align:start position:0% +rancho got here +is that clear what's happening + + align:start position:0% +is that clear what's happening + + + align:start position:0% +is that clear what's happening +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so then + + align:start position:0% + + + + align:start position:0% + +the final experiment was to stimulate + + align:start position:0% +the final experiment was to stimulate + + + align:start position:0% +the final experiment was to stimulate +the cutaneous nerve + + align:start position:0% +the cutaneous nerve + + + align:start position:0% +the cutaneous nerve +now if you go + + align:start position:0% +now if you go + + + align:start position:0% +now if you go +here + + align:start position:0% +here + + + align:start position:0% +here +you can after the + + align:start position:0% +you can after the + + + align:start position:0% +you can after the +dorsal and ventral roots come together + + align:start position:0% +dorsal and ventral roots come together + + + align:start position:0% +dorsal and ventral roots come together +you get into the peripheral nerve + + align:start position:0% +you get into the peripheral nerve + + + align:start position:0% +you get into the peripheral nerve +and there are nerves out here that go + + align:start position:0% +and there are nerves out here that go + + + align:start position:0% +and there are nerves out here that go +only to the skin + + align:start position:0% +only to the skin + + + align:start position:0% +only to the skin +other nerves are mixed they go to skin + + align:start position:0% +other nerves are mixed they go to skin + + + align:start position:0% +other nerves are mixed they go to skin +and muscle and there's some that go on + + align:start position:0% +and muscle and there's some that go on + + + align:start position:0% +and muscle and there's some that go on +into muscle just depends on where you + + align:start position:0% +into muscle just depends on where you + + + align:start position:0% +into muscle just depends on where you +are okay + + align:start position:0% +are okay + + + align:start position:0% +are okay +so they found the cutaneous nerve + + align:start position:0% +so they found the cutaneous nerve + + + align:start position:0% +so they found the cutaneous nerve +okay + + align:start position:0% +okay + + + align:start position:0% +okay +stimulated there with a + + align:start position:0% +stimulated there with a + + + align:start position:0% +stimulated there with a +sudden pulse of electricity + + align:start position:0% +sudden pulse of electricity + + + align:start position:0% +sudden pulse of electricity +they corrected for the conduction time + + align:start position:0% +they corrected for the conduction time + + + align:start position:0% +they corrected for the conduction time +okay and they found that with the + + align:start position:0% +okay and they found that with the + + + align:start position:0% +okay and they found that with the +cutaneous nerve they never got this + + align:start position:0% +cutaneous nerve they never got this + + + align:start position:0% +cutaneous nerve they never got this +first volley + + align:start position:0% +first volley + + + align:start position:0% +first volley +this one + + align:start position:0% +this one + + + align:start position:0% +this one +there always seemed to be at least two + + align:start position:0% +there always seemed to be at least two + + + align:start position:0% +there always seemed to be at least two +or more synapses + + align:start position:0% +or more synapses + + + align:start position:0% +or more synapses +between the cutaneous nerve and the + + align:start position:0% +between the cutaneous nerve and the + + + align:start position:0% +between the cutaneous nerve and the +motor neurons the activation of the + + align:start position:0% +motor neurons the activation of the + + + align:start position:0% +motor neurons the activation of the +motor neurons and the actual potentials + + align:start position:0% +motor neurons and the actual potentials + + + align:start position:0% +motor neurons and the actual potentials +that actually appear in the ventral root + + align:start position:0% +that actually appear in the ventral root + + + align:start position:0% +that actually appear in the ventral root +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so that was how it was demonstrated + + align:start position:0% + + + + align:start position:0% + +cutaneous reflexes + + align:start position:0% +cutaneous reflexes + + + align:start position:0% +cutaneous reflexes +are never monosynaptic + + align:start position:0% +are never monosynaptic + + + align:start position:0% +are never monosynaptic +they always involve at least two + + align:start position:0% +they always involve at least two + + + align:start position:0% +they always involve at least two +synapses + + align:start position:0% +synapses + + + align:start position:0% +synapses +and it was also the way they + + align:start position:0% +and it was also the way they + + + align:start position:0% +and it was also the way they +demonstrated + + align:start position:0% + + + + align:start position:0% + +the first evidence for a clear synaptic + + align:start position:0% +the first evidence for a clear synaptic + + + align:start position:0% +the first evidence for a clear synaptic +delay + + align:start position:0% + + + + align:start position:0% + +now when they trigger that reflex the + + align:start position:0% +now when they trigger that reflex the + + + align:start position:0% +now when they trigger that reflex the +other things happen too + + align:start position:0% +other things happen too + + + align:start position:0% +other things happen too +when you trigger at a flexion reflex + + align:start position:0% +when you trigger at a flexion reflex + + + align:start position:0% +when you trigger at a flexion reflex +let's say you trigger withdrawal of the + + align:start position:0% +let's say you trigger withdrawal of the + + + align:start position:0% +let's say you trigger withdrawal of the +arm + + align:start position:0% +arm + + + align:start position:0% +arm +not only do you activate flexure muscles + + align:start position:0% +not only do you activate flexure muscles + + + align:start position:0% +not only do you activate flexure muscles +but you also relax extensor muscles + + align:start position:0% +but you also relax extensor muscles + + + align:start position:0% +but you also relax extensor muscles +that's called reciprocal inhibition + + align:start position:0% +that's called reciprocal inhibition + + + align:start position:0% +that's called reciprocal inhibition +okay it's a pretty general principle + + align:start position:0% +okay it's a pretty general principle + + + align:start position:0% +okay it's a pretty general principle +to avoid conflict + + align:start position:0% +to avoid conflict + + + align:start position:0% +to avoid conflict +you get rid of the competing you reduce + + align:start position:0% +you get rid of the competing you reduce + + + align:start position:0% +you get rid of the competing you reduce +activity in the competing response + + align:start position:0% +activity in the competing response + + + align:start position:0% +activity in the competing response +systems it happens in brain mechanisms + + align:start position:0% +systems it happens in brain mechanisms + + + align:start position:0% +systems it happens in brain mechanisms +too it happens during fixed action + + align:start position:0% +too it happens during fixed action + + + align:start position:0% +too it happens during fixed action +patterns okay + + align:start position:0% + + + + align:start position:0% + +think of conflict in an animal now if he + + align:start position:0% +think of conflict in an animal now if he + + + align:start position:0% +think of conflict in an animal now if he +gets stimuli + + align:start position:0% +gets stimuli + + + align:start position:0% +gets stimuli +that can trigger approach to food and + + align:start position:0% +that can trigger approach to food and + + + align:start position:0% +that can trigger approach to food and +escape from a predator + + align:start position:0% +escape from a predator + + + align:start position:0% +escape from a predator +which which would you want to + + align:start position:0% +which which would you want to + + + align:start position:0% +which which would you want to +inhibit the other response + + align:start position:0% +inhibit the other response + + + align:start position:0% +inhibit the other response +well of course the escape response + + align:start position:0% +well of course the escape response + + + align:start position:0% +well of course the escape response +should inhibit the feeding + + align:start position:0% +should inhibit the feeding + + + align:start position:0% +should inhibit the feeding +and it generally does + + align:start position:0% +and it generally does + + + align:start position:0% +and it generally does +the animal drops what he's doing and + + align:start position:0% +the animal drops what he's doing and + + + align:start position:0% +the animal drops what he's doing and +freezes or runs + + align:start position:0% + + + + align:start position:0% + +but it happens at this very low level in + + align:start position:0% +but it happens at this very low level in + + + align:start position:0% +but it happens at this very low level in +the spinal cord + + align:start position:0% +the spinal cord + + + align:start position:0% +the spinal cord +with reciprocal inhibition of extensors + + align:start position:0% +with reciprocal inhibition of extensors + + + align:start position:0% +with reciprocal inhibition of extensors +i just point out here that it doesn't + + align:start position:0% +i just point out here that it doesn't + + + align:start position:0% +i just point out here that it doesn't +always work with higher systems should i + + align:start position:0% +always work with higher systems should i + + + align:start position:0% +always work with higher systems should i +watch tv or should i study + + align:start position:0% +watch tv or should i study + + + align:start position:0% +watch tv or should i study +sometimes you just experience the + + align:start position:0% +sometimes you just experience the + + + align:start position:0% +sometimes you just experience the +conflict and as we grow older we hope + + align:start position:0% +conflict and as we grow older we hope + + + align:start position:0% +conflict and as we grow older we hope +some of us anyway get better and better + + align:start position:0% +some of us anyway get better and better + + + align:start position:0% +some of us anyway get better and better +at resolving conflicts + + align:start position:0% +at resolving conflicts + + + align:start position:0% +at resolving conflicts +but we never get rid of them + + align:start position:0% + + + + align:start position:0% + +other things happen too + + align:start position:0% +other things happen too + + + align:start position:0% +other things happen too +when we trigger this let's say we + + align:start position:0% +when we trigger this let's say we + + + align:start position:0% +when we trigger this let's say we +trigger withdrawal of the leg + + align:start position:0% +trigger withdrawal of the leg + + + align:start position:0% +trigger withdrawal of the leg +it would be a tendency for the + + align:start position:0% +it would be a tendency for the + + + align:start position:0% +it would be a tendency for the +animal to fall over + + align:start position:0% +animal to fall over + + + align:start position:0% +animal to fall over +lose this balance very easily there's + + align:start position:0% +lose this balance very easily there's + + + align:start position:0% +lose this balance very easily there's +usually a cross extension reflex so + + align:start position:0% +usually a cross extension reflex so + + + align:start position:0% +usually a cross extension reflex so +there will be fibers coming from + + align:start position:0% +there will be fibers coming from + + + align:start position:0% +there will be fibers coming from +interneurons that are triggered + + align:start position:0% + + + + align:start position:0% + +by the cutaneous activity + + align:start position:0% +by the cutaneous activity + + + align:start position:0% +by the cutaneous activity +okay we'll cross over to the other side + + align:start position:0% +okay we'll cross over to the other side + + + align:start position:0% +okay we'll cross over to the other side +but instead of activating flexion + + align:start position:0% +but instead of activating flexion + + + align:start position:0% +but instead of activating flexion +they'll activate extension + + align:start position:0% +they'll activate extension + + + align:start position:0% +they'll activate extension +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so often if you see that happen a person + + align:start position:0% +so often if you see that happen a person + + + align:start position:0% +so often if you see that happen a person +will go like that + + align:start position:0% +will go like that + + + align:start position:0% +will go like that +because he's extending + + align:start position:0% +because he's extending + + + align:start position:0% +because he's extending +the leg and the initial movement is + + align:start position:0% +the leg and the initial movement is + + + align:start position:0% +the leg and the initial movement is +automatic + + align:start position:0% +automatic + + + align:start position:0% +automatic +and then of course the stimulator + + align:start position:0% +and then of course the stimulator + + + align:start position:0% +and then of course the stimulator +reflexes will come into play and tend to + + align:start position:0% +reflexes will come into play and tend to + + + align:start position:0% +reflexes will come into play and tend to +keep him on his feet + + align:start position:0% +keep him on his feet + + + align:start position:0% +keep him on his feet +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now if it's very intense + + align:start position:0% +now if it's very intense + + + align:start position:0% +now if it's very intense +it won't just be his foot but withdraws + + align:start position:0% +it won't just be his foot but withdraws + + + align:start position:0% +it won't just be his foot but withdraws +or just his leg he might get more + + align:start position:0% +or just his leg he might get more + + + align:start position:0% +or just his leg he might get more +general flexion of his body + + align:start position:0% +general flexion of his body + + + align:start position:0% +general flexion of his body +in some cases it's difficult to maintain + + align:start position:0% +in some cases it's difficult to maintain + + + align:start position:0% +in some cases it's difficult to maintain +balance + + align:start position:0% +balance + + + align:start position:0% +balance +but generally the crossed extension + + align:start position:0% +but generally the crossed extension + + + align:start position:0% +but generally the crossed extension +reflex will aid that maintaining of + + align:start position:0% +reflex will aid that maintaining of + + + align:start position:0% +reflex will aid that maintaining of +posture + + align:start position:0% + + + + align:start position:0% + +let's just think briefly about other + + align:start position:0% +let's just think briefly about other + + + align:start position:0% +let's just think briefly about other +modalities + + align:start position:0% +modalities + + + align:start position:0% +modalities +what happens with intense light + + align:start position:0% + + + + align:start position:0% + +if light is very bright you get + + align:start position:0% +if light is very bright you get + + + align:start position:0% +if light is very bright you get +something like a withdrawal from the + + align:start position:0% +something like a withdrawal from the + + + align:start position:0% +something like a withdrawal from the +stimulus anyway because you get + + align:start position:0% +stimulus anyway because you get + + + align:start position:0% +stimulus anyway because you get +constriction of the pupils + + align:start position:0% +constriction of the pupils + + + align:start position:0% +constriction of the pupils +okay to protect the retina from too much + + align:start position:0% +okay to protect the retina from too much + + + align:start position:0% +okay to protect the retina from too much +light + + align:start position:0% + + + + align:start position:0% + +pupillary + + align:start position:0% +pupillary + + + align:start position:0% +pupillary +contraction does other things too it + + align:start position:0% +contraction does other things too it + + + align:start position:0% +contraction does other things too it +increases + + align:start position:0% +increases + + + align:start position:0% +increases +the resolution possible resolution of + + align:start position:0% +the resolution possible resolution of + + + align:start position:0% +the resolution possible resolution of +the image + + align:start position:0% +the image + + + align:start position:0% +the image +even with poor + + align:start position:0% +even with poor + + + align:start position:0% +even with poor +focus on the retina + + align:start position:0% +focus on the retina + + + align:start position:0% +focus on the retina +if the pupils are very small you will + + align:start position:0% +if the pupils are very small you will + + + align:start position:0% +if the pupils are very small you will +still have an image that's in focus + + align:start position:0% +still have an image that's in focus + + + align:start position:0% +still have an image that's in focus +that's the principle of the pinhole + + align:start position:0% +that's the principle of the pinhole + + + align:start position:0% +that's the principle of the pinhole +camera + + align:start position:0% +camera + + + align:start position:0% +camera +okay but the main thing here is with + + align:start position:0% +okay but the main thing here is with + + + align:start position:0% +okay but the main thing here is with +intense light + + align:start position:0% +intense light + + + align:start position:0% +intense light +the pupils will constrict protect with + + align:start position:0% +the pupils will constrict protect with + + + align:start position:0% +the pupils will constrict protect with +intense sound there's something very + + align:start position:0% +intense sound there's something very + + + align:start position:0% +intense sound there's something very +similar + + align:start position:0% +similar + + + align:start position:0% +similar +there are actually little muscles in the + + align:start position:0% +there are actually little muscles in the + + + align:start position:0% +there are actually little muscles in the +inner ear that will tense up and reduce + + align:start position:0% +inner ear that will tense up and reduce + + + align:start position:0% +inner ear that will tense up and reduce +the oscillations of the middle ear bones + + align:start position:0% +the oscillations of the middle ear bones + + + align:start position:0% +the oscillations of the middle ear bones +and protect + + align:start position:0% +and protect + + + align:start position:0% +and protect +that system from damage + + align:start position:0% + + + + align:start position:0% + +novel input + + align:start position:0% +novel input + + + align:start position:0% +novel input +does something very different + + align:start position:0% +does something very different + + + align:start position:0% +does something very different +when input is very novel we also respond + + align:start position:0% +when input is very novel we also respond + + + align:start position:0% +when input is very novel we also respond +now this generally to detect the novelty + + align:start position:0% +now this generally to detect the novelty + + + align:start position:0% +now this generally to detect the novelty +we need + + align:start position:0% +we need + + + align:start position:0% +we need +brain mechanisms of midbrain or + + align:start position:0% +brain mechanisms of midbrain or + + + align:start position:0% +brain mechanisms of midbrain or +forebrain + + align:start position:0% +forebrain + + + align:start position:0% +forebrain +it tends to + + align:start position:0% +it tends to + + + align:start position:0% +it tends to +result in an increased sensitivity to + + align:start position:0% +result in an increased sensitivity to + + + align:start position:0% +result in an increased sensitivity to +stimuli + + align:start position:0% +stimuli + + + align:start position:0% +stimuli +that happens in some other sensory + + align:start position:0% +that happens in some other sensory + + + align:start position:0% +that happens in some other sensory +visual auditory systems + + align:start position:0% +visual auditory systems + + + align:start position:0% +visual auditory systems +very different from the effects of + + align:start position:0% +very different from the effects of + + + align:start position:0% +very different from the effects of +intense activity that could + + align:start position:0% +intense activity that could + + + align:start position:0% +intense activity that could +are threatening potentially threatening + + align:start position:0% + + + + align:start position:0% + +now i mentioned that there's an opposite + + align:start position:0% +now i mentioned that there's an opposite + + + align:start position:0% +now i mentioned that there's an opposite +kind of reflex you tend to see it in + + align:start position:0% +kind of reflex you tend to see it in + + + align:start position:0% +kind of reflex you tend to see it in +babies + + align:start position:0% +babies + + + align:start position:0% +babies +if you take + + align:start position:0% +if you take + + + align:start position:0% +if you take +if you take a baby even a newborn okay + + align:start position:0% +if you take a baby even a newborn okay + + + align:start position:0% +if you take a baby even a newborn okay +and stroke the back of its hand gently + + align:start position:0% +and stroke the back of its hand gently + + + align:start position:0% +and stroke the back of its hand gently +often it will extend the hand even turn + + align:start position:0% +often it will extend the hand even turn + + + align:start position:0% +often it will extend the hand even turn +and is often followed by a grasp + + align:start position:0% +and is often followed by a grasp + + + align:start position:0% +and is often followed by a grasp +and of course we think + + align:start position:0% +and of course we think + + + align:start position:0% +and of course we think +what an intelligent little child he + + align:start position:0% +what an intelligent little child he + + + align:start position:0% +what an intelligent little child he +likes to grab my hand but actually it's + + align:start position:0% +likes to grab my hand but actually it's + + + align:start position:0% +likes to grab my hand but actually it's +a reflex spinal reflex + + align:start position:0% + + + + align:start position:0% + +same is true of early smiling reflexes + + align:start position:0% + + + + align:start position:0% + +and we normally don't see that in adults + + align:start position:0% +and we normally don't see that in adults + + + align:start position:0% +and we normally don't see that in adults +but there are situations where we do see + + align:start position:0% +but there are situations where we do see + + + align:start position:0% +but there are situations where we do see +magnet reflexes + + align:start position:0% + + + + align:start position:0% + +for example just take the second one + + align:start position:0% +for example just take the second one + + + align:start position:0% +for example just take the second one +here and brain damage patients + + align:start position:0% + + + + align:start position:0% + +with large frontal lobe lesions you can + + align:start position:0% +with large frontal lobe lesions you can + + + align:start position:0% +with large frontal lobe lesions you can +get enhancement of magnet and glass + + align:start position:0% +get enhancement of magnet and glass + + + align:start position:0% +get enhancement of magnet and glass +reflexes + + align:start position:0% + + + + align:start position:0% + +so if you have a frontal lobe patient + + align:start position:0% +so if you have a frontal lobe patient + + + align:start position:0% +so if you have a frontal lobe patient +lying in a bed and the nurse walks by + + align:start position:0% +lying in a bed and the nurse walks by + + + align:start position:0% +lying in a bed and the nurse walks by +and she brushes his hand you know he can + + align:start position:0% +and she brushes his hand you know he can + + + align:start position:0% +and she brushes his hand you know he can +turn out and grab her and you think what + + align:start position:0% +turn out and grab her and you think what + + + align:start position:0% +turn out and grab her and you think what +a fresh fellow + + align:start position:0% +a fresh fellow + + + align:start position:0% +a fresh fellow +but actually it could be a reflex it + + align:start position:0% +but actually it could be a reflex it + + + align:start position:0% +but actually it could be a reflex it +could be a magnet reflex and he might + + align:start position:0% +could be a magnet reflex and he might + + + align:start position:0% +could be a magnet reflex and he might +not actually know until after it's + + align:start position:0% +not actually know until after it's + + + align:start position:0% +not actually know until after it's +happened what's going on + + align:start position:0% +happened what's going on + + + align:start position:0% +happened what's going on +you can also get enhancement of the + + align:start position:0% +you can also get enhancement of the + + + align:start position:0% +you can also get enhancement of the +withdrawal reflexes with large parietal + + align:start position:0% +withdrawal reflexes with large parietal + + + align:start position:0% +withdrawal reflexes with large parietal +lobe lesions and the other types of + + align:start position:0% +lobe lesions and the other types of + + + align:start position:0% +lobe lesions and the other types of +withdrawal reflexes i've seen it in + + align:start position:0% +withdrawal reflexes i've seen it in + + + align:start position:0% +withdrawal reflexes i've seen it in +animals with large + + align:start position:0% +animals with large + + + align:start position:0% +animals with large +posterior neocortical lesions that + + align:start position:0% +posterior neocortical lesions that + + + align:start position:0% +posterior neocortical lesions that +damage parietal areas + + align:start position:0% +damage parietal areas + + + align:start position:0% +damage parietal areas +so we call those automatisms + + align:start position:0% +so we call those automatisms + + + align:start position:0% +so we call those automatisms +they can occur in spite of conscious + + align:start position:0% +they can occur in spite of conscious + + + align:start position:0% +they can occur in spite of conscious +efforts to control them + + align:start position:0% + + + + align:start position:0% + +what about normally + + align:start position:0% +what about normally + + + align:start position:0% +what about normally +well + + align:start position:0% +well + + + align:start position:0% +well +we can certainly get enhancement of + + align:start position:0% +we can certainly get enhancement of + + + align:start position:0% +we can certainly get enhancement of +withdrawal reflexes + + align:start position:0% +withdrawal reflexes + + + align:start position:0% +withdrawal reflexes +let's look at this example + + align:start position:0% +let's look at this example + + + align:start position:0% +let's look at this example +say you've gone down into a dark + + align:start position:0% +say you've gone down into a dark + + + align:start position:0% +say you've gone down into a dark +basement and you're looking for a tool + + align:start position:0% +basement and you're looking for a tool + + + align:start position:0% +basement and you're looking for a tool +there and you can't find the light + + align:start position:0% +there and you can't find the light + + + align:start position:0% +there and you can't find the light +and everything's fine until + + align:start position:0% + + + + align:start position:0% + +your apartment mate yells down the + + align:start position:0% +your apartment mate yells down the + + + align:start position:0% +your apartment mate yells down the +stairs and says oh by the way i i saw + + align:start position:0% +stairs and says oh by the way i i saw + + + align:start position:0% +stairs and says oh by the way i i saw +rats down there today what happens + + align:start position:0% +rats down there today what happens + + + align:start position:0% +rats down there today what happens +you touch almost anything and you pull + + align:start position:0% +you touch almost anything and you pull + + + align:start position:0% +you touch almost anything and you pull +your hand back involuntarily because the + + align:start position:0% +your hand back involuntarily because the + + + align:start position:0% +your hand back involuntarily because the +threshold for the withdrawal reflexes + + align:start position:0% +threshold for the withdrawal reflexes + + + align:start position:0% +threshold for the withdrawal reflexes +has gone way down + + align:start position:0% +has gone way down + + + align:start position:0% +has gone way down +similarly if you're + + align:start position:0% +similarly if you're + + + align:start position:0% +similarly if you're +the other example i like is the + + align:start position:0% +the other example i like is the + + + align:start position:0% +the other example i like is the +in broad daylight you're looking in tall + + align:start position:0% +in broad daylight you're looking in tall + + + align:start position:0% +in broad daylight you're looking in tall +grass say for a golf ball or a baseball + + align:start position:0% +grass say for a golf ball or a baseball + + + align:start position:0% +grass say for a golf ball or a baseball +and you can't see so you're groping with + + align:start position:0% +and you can't see so you're groping with + + + align:start position:0% +and you can't see so you're groping with +your hand if somebody tells you you know + + align:start position:0% +your hand if somebody tells you you know + + + align:start position:0% +your hand if somebody tells you you know +oh there's snakes there be careful + + align:start position:0% +oh there's snakes there be careful + + + align:start position:0% +oh there's snakes there be careful +the same thing will happen you'll + + align:start position:0% +the same thing will happen you'll + + + align:start position:0% +the same thing will happen you'll +enhance by descending activity to the + + align:start position:0% +enhance by descending activity to the + + + align:start position:0% +enhance by descending activity to the +cord you'll enhance + + align:start position:0% +cord you'll enhance + + + align:start position:0% +cord you'll enhance +withdrawal reflexes okay so you will now + + align:start position:0% +withdrawal reflexes okay so you will now + + + align:start position:0% +withdrawal reflexes okay so you will now +trigger them with much less input + + align:start position:0% + + + + align:start position:0% + +so i mentioned the effects of stimulus + + align:start position:0% +so i mentioned the effects of stimulus + + + align:start position:0% +so i mentioned the effects of stimulus +novelty + + align:start position:0% +novelty + + + align:start position:0% +novelty +how they increase sensitivity + + align:start position:0% +how they increase sensitivity + + + align:start position:0% +how they increase sensitivity +why would we want to be more sensitive + + align:start position:0% +why would we want to be more sensitive + + + align:start position:0% +why would we want to be more sensitive +partly because + + align:start position:0% +partly because + + + align:start position:0% +partly because +novelty can indicate problems possible + + align:start position:0% +novelty can indicate problems possible + + + align:start position:0% +novelty can indicate problems possible +problems it's something unknown will + + align:start position:0% +problems it's something unknown will + + + align:start position:0% +problems it's something unknown will +become more hesitant we'll show more + + align:start position:0% +become more hesitant we'll show more + + + align:start position:0% +become more hesitant we'll show more +fear and avoidance + + align:start position:0% +fear and avoidance + + + align:start position:0% +fear and avoidance +that happens with increased novelty + + align:start position:0% +that happens with increased novelty + + + align:start position:0% +that happens with increased novelty +with milder novelty we tend to show the + + align:start position:0% +with milder novelty we tend to show the + + + align:start position:0% +with milder novelty we tend to show the +opposite we show curiosity approach and + + align:start position:0% +opposite we show curiosity approach and + + + align:start position:0% +opposite we show curiosity approach and +avoidance and these are very general + + align:start position:0% +avoidance and these are very general + + + align:start position:0% +avoidance and these are very general +things that happen you can study this in + + align:start position:0% +things that happen you can study this in + + + align:start position:0% +things that happen you can study this in +in many different animals + + align:start position:0% +in many different animals + + + align:start position:0% +in many different animals +but especially the mammals i think all + + align:start position:0% +but especially the mammals i think all + + + align:start position:0% +but especially the mammals i think all +the mammals show a lot of curiosity + + align:start position:0% + + + + align:start position:0% + +when we deal with something like + + align:start position:0% +when we deal with something like + + + align:start position:0% +when we deal with something like +obtaining food or water we have + + align:start position:0% +obtaining food or water we have + + + align:start position:0% +obtaining food or water we have +additional influences other than novelty + + align:start position:0% +additional influences other than novelty + + + align:start position:0% +additional influences other than novelty +we have a special role of olfaction + + align:start position:0% +we have a special role of olfaction + + + align:start position:0% +we have a special role of olfaction +which we know happened very early in + + align:start position:0% +which we know happened very early in + + + align:start position:0% +which we know happened very early in +evolution + + align:start position:0% +evolution + + + align:start position:0% +evolution +and then with the other distance + + align:start position:0% +and then with the other distance + + + align:start position:0% +and then with the other distance +receptors we got other effects important + + align:start position:0% +receptors we got other effects important + + + align:start position:0% +receptors we got other effects important +for approach + + align:start position:0% +for approach + + + align:start position:0% +for approach +and avoidance in this case mostly + + align:start position:0% +and avoidance in this case mostly + + + align:start position:0% +and avoidance in this case mostly +approach + + align:start position:0% + + + + align:start position:0% + +and limbic forebrain mechanisms became + + align:start position:0% +and limbic forebrain mechanisms became + + + align:start position:0% +and limbic forebrain mechanisms became +more and more important and i'm just + + align:start position:0% +more and more important and i'm just + + + align:start position:0% +more and more important and i'm just +asking this for you to think about + + align:start position:0% +asking this for you to think about + + + align:start position:0% +asking this for you to think about +what's the major additional influence of + + align:start position:0% +what's the major additional influence of + + + align:start position:0% +what's the major additional influence of +the limbic forebrain mechanisms + + align:start position:0% +the limbic forebrain mechanisms + + + align:start position:0% +the limbic forebrain mechanisms +olympic forebrain we say are the + + align:start position:0% +olympic forebrain we say are the + + + align:start position:0% +olympic forebrain we say are the +mechanisms that control our emotions and + + align:start position:0% +mechanisms that control our emotions and + + + align:start position:0% +mechanisms that control our emotions and +our motivations + + align:start position:0% +our motivations + + + align:start position:0% +our motivations +but we had that + + align:start position:0% +but we had that + + + align:start position:0% +but we had that +animals even without much of a forebrain + + align:start position:0% +animals even without much of a forebrain + + + align:start position:0% +animals even without much of a forebrain +certainly still + + align:start position:0% +certainly still + + + align:start position:0% +certainly still +approached food and water they could + + align:start position:0% +approached food and water they could + + + align:start position:0% +approached food and water they could +still forage with + + align:start position:0% +still forage with + + + align:start position:0% +still forage with +midbrain and between brain mechanisms + + align:start position:0% +midbrain and between brain mechanisms + + + align:start position:0% +midbrain and between brain mechanisms +so what is the limbic forebrain adding + + align:start position:0% +so what is the limbic forebrain adding + + + align:start position:0% +so what is the limbic forebrain adding +one thing it does is + + align:start position:0% +one thing it does is + + + align:start position:0% +one thing it does is +it gives + + align:start position:0% +it gives + + + align:start position:0% +it gives +objects in the environment that are + + align:start position:0% +objects in the environment that are + + + align:start position:0% +objects in the environment that are +originally neutral + + align:start position:0% +originally neutral + + + align:start position:0% +originally neutral +it gives them what we call an effective + + align:start position:0% +it gives them what we call an effective + + + align:start position:0% +it gives them what we call an effective +tag we tag things we give them a + + align:start position:0% +tag we tag things we give them a + + + align:start position:0% +tag we tag things we give them a +property + + align:start position:0% +property + + + align:start position:0% +property +okay about how good they are bad they + + align:start position:0% +okay about how good they are bad they + + + align:start position:0% +okay about how good they are bad they +are + + align:start position:0% +are + + + align:start position:0% +are +okay we do that to people too + + align:start position:0% +okay we do that to people too + + + align:start position:0% +okay we do that to people too +and this is + + align:start position:0% +and this is + + + align:start position:0% +and this is +because of limbic system activity and + + align:start position:0% +because of limbic system activity and + + + align:start position:0% +because of limbic system activity and +limbic connections + + align:start position:0% +limbic connections + + + align:start position:0% +limbic connections +to the structure to the hypothalamus and + + align:start position:0% +to the structure to the hypothalamus and + + + align:start position:0% +to the structure to the hypothalamus and +other structures involved + + align:start position:0% +other structures involved + + + align:start position:0% +other structures involved +in foraging + + align:start position:0% +in foraging + + + align:start position:0% +in foraging +basically motivation modulation of our + + align:start position:0% +basically motivation modulation of our + + + align:start position:0% +basically motivation modulation of our +motive the motivational effects of + + align:start position:0% +motive the motivational effects of + + + align:start position:0% +motive the motivational effects of +things + + align:start position:0% + + + + align:start position:0% + +and in addition it allows us + + align:start position:0% +and in addition it allows us + + + align:start position:0% +and in addition it allows us +because of learning to be rewarded + + align:start position:0% +because of learning to be rewarded + + + align:start position:0% +because of learning to be rewarded +by things that might not initially we + + align:start position:0% +by things that might not initially we + + + align:start position:0% +by things that might not initially we +might initially be rewarded by taste + + align:start position:0% +might initially be rewarded by taste + + + align:start position:0% +might initially be rewarded by taste +primarily for a + + align:start position:0% +primarily for a + + + align:start position:0% +primarily for a +taste of food but then later we learn + + align:start position:0% +taste of food but then later we learn + + + align:start position:0% +taste of food but then later we learn +certain foods stays good certain food + + align:start position:0% +certain foods stays good certain food + + + align:start position:0% +certain foods stays good certain food +stays bad and we learn by their + + align:start position:0% +stays bad and we learn by their + + + align:start position:0% +stays bad and we learn by their +appearance we don't have to taste them + + align:start position:0% +appearance we don't have to taste them + + + align:start position:0% +appearance we don't have to taste them +every time + + align:start position:0% +every time + + + align:start position:0% +every time +okay we learn + + align:start position:0% +okay we learn + + + align:start position:0% +okay we learn +to associate + + align:start position:0% + + + + align:start position:0% + +tastes with certain visual objects or + + align:start position:0% +tastes with certain visual objects or + + + align:start position:0% +tastes with certain visual objects or +even auditory or semi-sensory okay + + align:start position:0% +even auditory or semi-sensory okay + + + align:start position:0% +even auditory or semi-sensory okay +that always involves the limbic + + align:start position:0% +that always involves the limbic + + + align:start position:0% +that always involves the limbic +forebrain + + align:start position:0% +forebrain + + + align:start position:0% +forebrain +okay + + align:start position:0% + + + + align:start position:0% + +we don't have much more time this is + + align:start position:0% +we don't have much more time this is + + + align:start position:0% +we don't have much more time this is +what we're gonna do next time we're + + align:start position:0% +what we're gonna do next time we're + + + align:start position:0% +what we're gonna do next time we're +going to talk about the muscle spindle + + align:start position:0% +going to talk about the muscle spindle + + + align:start position:0% +going to talk about the muscle spindle +organs detection of muscle stretch + + align:start position:0% +organs detection of muscle stretch + + + align:start position:0% +organs detection of muscle stretch +and go through these topics and talking + + align:start position:0% +and go through these topics and talking + + + align:start position:0% +and go through these topics and talking +about + + align:start position:0% +about + + + align:start position:0% +about +the monosynaptic reflexes of the spinal + + align:start position:0% +the monosynaptic reflexes of the spinal + + + align:start position:0% +the monosynaptic reflexes of the spinal +cord \ No newline at end of file diff --git a/avQ2XUzbsgk.txt b/avQ2XUzbsgk.txt new file mode 100644 index 0000000000000000000000000000000000000000..06d357c4a6f8cd292ec04facaafaa6d001065731 --- /dev/null +++ b/avQ2XUzbsgk.txt @@ -0,0 +1,2955 @@ +align:start position:0% + +what is a red Berg Adam well it's a an + + align:start position:0% +what is a red Berg Adam well it's a an + + + align:start position:0% +what is a red Berg Adam well it's a an +atom can be a red Berg atom if the + + align:start position:0% +atom can be a red Berg atom if the + + + align:start position:0% +atom can be a red Berg atom if the +outermost electron is in a very high + + align:start position:0% +outermost electron is in a very high + + + align:start position:0% +outermost electron is in a very high +principal quantum number that's the + + align:start position:0% +principal quantum number that's the + + + align:start position:0% +principal quantum number that's the +definition of a red Berg atom the last + + align:start position:0% +definition of a red Berg atom the last + + + align:start position:0% +definition of a red Berg atom the last +electron is in n little and very large + + align:start position:0% +electron is in n little and very large + + + align:start position:0% +electron is in n little and very large +now that is very interesting because + + align:start position:0% +now that is very interesting because + + + align:start position:0% +now that is very interesting because +when that happens with Berg atoms when + + align:start position:0% +when that happens with Berg atoms when + + + align:start position:0% +when that happens with Berg atoms when +that happens you have a nucleus with + + align:start position:0% +that happens you have a nucleus with + + + align:start position:0% +that happens you have a nucleus with +charge ze + + align:start position:0% +charge ze + + + align:start position:0% +charge ze +and you have lots of electrons and the + + align:start position:0% +and you have lots of electrons and the + + + align:start position:0% +and you have lots of electrons and the +last electron suppose the last electrode + + align:start position:0% +last electron suppose the last electrode + + + align:start position:0% +last electron suppose the last electrode +is in an orbit further out you see the + + align:start position:0% +is in an orbit further out you see the + + + align:start position:0% +is in an orbit further out you see the +orbits of do become further out in + + align:start position:0% +orbits of do become further out in + + + align:start position:0% +orbits of do become further out in +general and the suppose the last + + align:start position:0% +general and the suppose the last + + + align:start position:0% +general and the suppose the last +electrode is in some large value of + + align:start position:0% +electrode is in some large value of + + + align:start position:0% +electrode is in some large value of +little n so it's somewhat out so here is + + align:start position:0% +little n so it's somewhat out so here is + + + align:start position:0% +little n so it's somewhat out so here is +the last electron this electron sees a + + align:start position:0% +the last electron this electron sees a + + + align:start position:0% +the last electron this electron sees a +nucleus with charge Z but it also sees Z + + align:start position:0% +nucleus with charge Z but it also sees Z + + + align:start position:0% +nucleus with charge Z but it also sees Z +minus one electrons all the other + + align:start position:0% +minus one electrons all the other + + + align:start position:0% +minus one electrons all the other +electrons see the last electrode is + + align:start position:0% +electrons see the last electrode is + + + align:start position:0% +electrons see the last electrode is +outside the nucleus and the cloud of the + + align:start position:0% +outside the nucleus and the cloud of the + + + align:start position:0% +outside the nucleus and the cloud of the +other electrons so the last electrode + + align:start position:0% +other electrons so the last electrode + + + align:start position:0% +other electrons so the last electrode +sees a charge plus 1 Z from here and Z + + align:start position:0% +sees a charge plus 1 Z from here and Z + + + align:start position:0% +sees a charge plus 1 Z from here and Z +minus 1 of the electrons so the last + + align:start position:0% +minus 1 of the electrons so the last + + + align:start position:0% +minus 1 of the electrons so the last +electrode sees charge 1 so in some sense + + align:start position:0% +electrode sees charge 1 so in some sense + + + align:start position:0% +electrode sees charge 1 so in some sense +to a good approximation the last + + align:start position:0% +to a good approximation the last + + + align:start position:0% +to a good approximation the last +electron says oh there's a hydrogen atom + + align:start position:0% +electron says oh there's a hydrogen atom + + + align:start position:0% +electron says oh there's a hydrogen atom +here I'm part of a hydrogen atom I don't + + align:start position:0% +here I'm part of a hydrogen atom I don't + + + align:start position:0% +here I'm part of a hydrogen atom I don't +see my friends the other electrons are + + align:start position:0% +see my friends the other electrons are + + + align:start position:0% +see my friends the other electrons are +too close to the Duke + + align:start position:0% +too close to the Duke + + + align:start position:0% +too close to the Duke +and I'm out there going around as if I + + align:start position:0% +and I'm out there going around as if I + + + align:start position:0% +and I'm out there going around as if I +were hydrogen so that's a very nice + + align:start position:0% +were hydrogen so that's a very nice + + + align:start position:0% +were hydrogen so that's a very nice +application of hydrogen atoms so the + + align:start position:0% +application of hydrogen atoms so the + + + align:start position:0% +application of hydrogen atoms so the +first question that we want to + + align:start position:0% +first question that we want to + + + align:start position:0% +first question that we want to +understand and it's again conceptually + + align:start position:0% +understand and it's again conceptually + + + align:start position:0% +understand and it's again conceptually +is what is the size if M is large what + + align:start position:0% +is what is the size if M is large what + + + align:start position:0% +is what is the size if M is large what +is the size of the atom now I must say I + + align:start position:0% +is the size of the atom now I must say I + + + align:start position:0% +is the size of the atom now I must say I +myself when I look at these things after + + align:start position:0% +myself when I look at these things after + + + align:start position:0% +myself when I look at these things after +a few years that I don't eat raw + + align:start position:0% +a few years that I don't eat raw + + + align:start position:0% +a few years that I don't eat raw +mechanics I look at here and say okay + + align:start position:0% +mechanics I look at here and say okay + + + align:start position:0% +mechanics I look at here and say okay +this is the solution maybe the size is + + align:start position:0% +this is the solution maybe the size is + + + align:start position:0% +this is the solution maybe the size is +an a0 and fortunately that's completely + + align:start position:0% +an a0 and fortunately that's completely + + + align:start position:0% +an a0 and fortunately that's completely +wrong and we're going to try to explain + + align:start position:0% +wrong and we're going to try to explain + + + align:start position:0% +wrong and we're going to try to explain +what was wrong in looking there you know + + align:start position:0% +what was wrong in looking there you know + + + align:start position:0% +what was wrong in looking there you know +you see your hydrogen atom wave function + + align:start position:0% +you see your hydrogen atom wave function + + + align:start position:0% +you see your hydrogen atom wave function +there's nothing like really the size + + align:start position:0% +there's nothing like really the size + + + align:start position:0% +there's nothing like really the size +there's no such precise definition as + + align:start position:0% +there's no such precise definition as + + + align:start position:0% +there's no such precise definition as +the size but you could say what's the + + align:start position:0% +the size but you could say what's the + + + align:start position:0% +the size but you could say what's the +expected value of the radius that's a + + align:start position:0% +expected value of the radius that's a + + + align:start position:0% +expected value of the radius that's a +reasonable definition of size and you + + align:start position:0% +reasonable definition of size and you + + + align:start position:0% +reasonable definition of size and you +know from this wave function is going to + + align:start position:0% +know from this wave function is going to + + + align:start position:0% +know from this wave function is going to +come out to a 0 a 0 over 2 to a 0 + + align:start position:0% +come out to a 0 a 0 over 2 to a 0 + + + align:start position:0% +come out to a 0 a 0 over 2 to a 0 +maybe PI over 2 a 0 something like that + + align:start position:0% +maybe PI over 2 a 0 something like that + + + align:start position:0% +maybe PI over 2 a 0 something like that +so from here you would say well it's + + align:start position:0% +so from here you would say well it's + + + align:start position:0% +so from here you would say well it's +going to come out to PI and a 0 or + + align:start position:0% +going to come out to PI and a 0 or + + + align:start position:0% +going to come out to PI and a 0 or +something like that but it's not true so + + align:start position:0% +something like that but it's not true so + + + align:start position:0% +something like that but it's not true so +how do we see that it's not true we'll + + align:start position:0% +how do we see that it's not true we'll + + + align:start position:0% +how do we see that it's not true we'll +take a little time in a few minutes but + + align:start position:0% +take a little time in a few minutes but + + + align:start position:0% +take a little time in a few minutes but +how can we get the size of that atom + + align:start position:0% +how can we get the size of that atom + + + align:start position:0% +how can we get the size of that atom +correctly in an intuitive way again want + + align:start position:0% +correctly in an intuitive way again want + + + align:start position:0% +correctly in an intuitive way again want +to just understand a few results about + + align:start position:0% +to just understand a few results about + + + align:start position:0% +to just understand a few results about +hydrogen + + align:start position:0% +hydrogen + + + align:start position:0% +hydrogen +them that become part of your intuition + + align:start position:0% +them that become part of your intuition + + + align:start position:0% +them that become part of your intuition +so the important result here is the + + align:start position:0% +so the important result here is the + + + align:start position:0% +so the important result here is the +virial theorem theorem now whenever I + + align:start position:0% +virial theorem theorem now whenever I + + + align:start position:0% +virial theorem theorem now whenever I +think of the virial theorem I said oh + + align:start position:0% +think of the virial theorem I said oh + + + align:start position:0% +think of the virial theorem I said oh +there was a factor of 2 or 1/2 there how + + align:start position:0% +there was a factor of 2 or 1/2 there how + + + align:start position:0% +there was a factor of 2 or 1/2 there how +did it go + + align:start position:0% +did it go + + + align:start position:0% +did it go +takes me a few seconds to try to + + align:start position:0% +takes me a few seconds to try to + + + align:start position:0% +takes me a few seconds to try to +reconstruct that it's this for the + + align:start position:0% +reconstruct that it's this for the + + + align:start position:0% +reconstruct that it's this for the +hydrogen system for any 1 over R + + align:start position:0% +hydrogen system for any 1 over R + + + align:start position:0% +hydrogen system for any 1 over R +potential there is this relation within + + align:start position:0% +potential there is this relation within + + + align:start position:0% +potential there is this relation within +the expectation value of the kinetic + + align:start position:0% +the expectation value of the kinetic + + + align:start position:0% +the expectation value of the kinetic +energy the potential energy you've seen + + align:start position:0% +energy the potential energy you've seen + + + align:start position:0% +energy the potential energy you've seen +that result probably a couple of times + + align:start position:0% +that result probably a couple of times + + + align:start position:0% +that result probably a couple of times +already in this course because it's a + + align:start position:0% +already in this course because it's a + + + align:start position:0% +already in this course because it's a +really important result it looks like ok + + align:start position:0% +really important result it looks like ok + + + align:start position:0% +really important result it looks like ok +just a theorem about these things but + + align:start position:0% +just a theorem about these things but + + + align:start position:0% +just a theorem about these things but +the intuition is really important so how + + align:start position:0% +the intuition is really important so how + + + align:start position:0% +the intuition is really important so how +does one remember picture that one way + + align:start position:0% +does one remember picture that one way + + + align:start position:0% +does one remember picture that one way +is the following and that's the way I + + align:start position:0% +is the following and that's the way I + + + align:start position:0% +is the following and that's the way I +like it + + align:start position:0% +like it + + + align:start position:0% +like it +oh I imagine the energy line here and + + align:start position:0% +oh I imagine the energy line here and + + + align:start position:0% +oh I imagine the energy line here and +here is zero and the one thing I + + align:start position:0% +here is zero and the one thing I + + + align:start position:0% +here is zero and the one thing I +remember is that yes there is a kinetic + + align:start position:0% +remember is that yes there is a kinetic + + + align:start position:0% +remember is that yes there is a kinetic +energy here and actually the bound state + + align:start position:0% +energy here and actually the bound state + + + align:start position:0% +energy here and actually the bound state +energy is exactly the same but opposite + + align:start position:0% + + + + align:start position:0% + +that's a way to remember that that's + + align:start position:0% +that's a way to remember that that's + + + align:start position:0% +that's a way to remember that that's +really what is going on that's the key + + align:start position:0% +really what is going on that's the key + + + align:start position:0% +really what is going on that's the key +thing the kinetic energy and the bound + + align:start position:0% +thing the kinetic energy and the bound + + + align:start position:0% +thing the kinetic energy and the bound +state energy are just of opposite signs + + align:start position:0% + + + + align:start position:0% + +why do we see that because then we have + + align:start position:0% +why do we see that because then we have + + + align:start position:0% +why do we see that because then we have +that V from this equation is minus 2t + + align:start position:0% +that V from this equation is minus 2t + + + align:start position:0% +that V from this equation is minus 2t +and if V is minus 2t means that T plus V + + align:start position:0% +and if V is minus 2t means that T plus V + + + align:start position:0% +and if V is minus 2t means that T plus V +is t minus 2 T and T plus V is a total + + align:start position:0% +is t minus 2 T and T plus V is a total + + + align:start position:0% +is t minus 2 T and T plus V is a total +energy + + align:start position:0% +energy + + + align:start position:0% +energy +so P plus V is equal to the total energy + + align:start position:0% +so P plus V is equal to the total energy + + + align:start position:0% +so P plus V is equal to the total energy +of the bound state for any stationary + + align:start position:0% +of the bound state for any stationary + + + align:start position:0% +of the bound state for any stationary +state this is true and this thing given + + align:start position:0% +state this is true and this thing given + + + align:start position:0% +state this is true and this thing given +this condition is minus T so that's + + align:start position:0% +this condition is minus T so that's + + + align:start position:0% +this condition is minus T so that's +that's the way we think of it so we then + + align:start position:0% +that's the way we think of it so we then + + + align:start position:0% +that's the way we think of it so we then +have a nice result because the + + align:start position:0% +have a nice result because the + + + align:start position:0% +have a nice result because the +expectation value of the potential would + + align:start position:0% +expectation value of the potential would + + + align:start position:0% +expectation value of the potential would +then be minus two times the expectation + + align:start position:0% +then be minus two times the expectation + + + align:start position:0% +then be minus two times the expectation +value of T which is itself - are the + + align:start position:0% +value of T which is itself - are the + + + align:start position:0% +value of T which is itself - are the +energy so you have a minus 2 times minus + + align:start position:0% +energy so you have a minus 2 times minus + + + align:start position:0% +energy so you have a minus 2 times minus +the energy and it's equal to the energy + + align:start position:0% +the energy and it's equal to the energy + + + align:start position:0% +the energy and it's equal to the energy +and this is correct the expectation + + align:start position:0% +and this is correct the expectation + + + align:start position:0% +and this is correct the expectation +value of V is the energy and expectation + + align:start position:0% +value of V is the energy and expectation + + + align:start position:0% +value of V is the energy and expectation +value of e V is negative and the energy + + align:start position:0% +value of e V is negative and the energy + + + align:start position:0% +value of e V is negative and the energy +is negative so what is this this is the + + align:start position:0% +is negative so what is this this is the + + + align:start position:0% +is negative so what is this this is the +expectation value of minus e squared + + align:start position:0% +expectation value of minus e squared + + + align:start position:0% +expectation value of minus e squared +over R in fact + + align:start position:0% +over R in fact + + + align:start position:0% +over R in fact +oh yeah I'll leave it like that so I'm + + align:start position:0% +oh yeah I'll leave it like that so I'm + + + align:start position:0% +oh yeah I'll leave it like that so I'm +back to Z equal 1 because we're talking + + align:start position:0% +back to Z equal 1 because we're talking + + + align:start position:0% +back to Z equal 1 because we're talking +about red Burke atoms Oh 2 EB I'm sorry + + align:start position:0% +about red Burke atoms Oh 2 EB I'm sorry + + + align:start position:0% +about red Burke atoms Oh 2 EB I'm sorry +here thank you + + align:start position:0% +here thank you + + + align:start position:0% +here thank you +okay so expectation value of the + + align:start position:0% +okay so expectation value of the + + + align:start position:0% +okay so expectation value of the +potential we have here and 2 times their + + align:start position:0% +potential we have here and 2 times their + + + align:start position:0% +potential we have here and 2 times their +energy yeah I would have gotten this + + align:start position:0% +energy yeah I would have gotten this + + + align:start position:0% +energy yeah I would have gotten this +wrong thanks for correcting it before it + + align:start position:0% +wrong thanks for correcting it before it + + + align:start position:0% +wrong thanks for correcting it before it +did damage to the derivation we have it + + align:start position:0% +did damage to the derivation we have it + + + align:start position:0% +did damage to the derivation we have it +there a squared over 2a not 1 over N + + align:start position:0% +there a squared over 2a not 1 over N + + + align:start position:0% +there a squared over 2a not 1 over N +squared so what can we cancel well the + + align:start position:0% +squared so what can we cancel well the + + + align:start position:0% +squared so what can we cancel well the +two + + align:start position:0% +two + + + align:start position:0% +two +so the e squares cancel the sines cancel + + align:start position:0% +so the e squares cancel the sines cancel + + + align:start position:0% +so the e squares cancel the sines cancel +and we get expectation value of one over + + align:start position:0% +and we get expectation value of one over + + + align:start position:0% +and we get expectation value of one over +R is equal to one over N squared a + + align:start position:0% +R is equal to one over N squared a + + + align:start position:0% +R is equal to one over N squared a +naught which is suggesting very clearly + + align:start position:0% +naught which is suggesting very clearly + + + align:start position:0% +naught which is suggesting very clearly +that the typical radius is not M a + + align:start position:0% +that the typical radius is not M a + + + align:start position:0% +that the typical radius is not M a +naught is N squared a naught so this is + + align:start position:0% +naught is N squared a naught so this is + + + align:start position:0% +naught is N squared a naught so this is +this is exact the virial theorem is + + align:start position:0% +this is exact the virial theorem is + + + align:start position:0% +this is exact the virial theorem is +exact the energies exact this is exact + + align:start position:0% +exact the energies exact this is exact + + + align:start position:0% +exact the energies exact this is exact +that's not quite the expectation value + + align:start position:0% +that's not quite the expectation value + + + align:start position:0% +that's not quite the expectation value +of r the expectation value of r is not + + align:start position:0% +of r the expectation value of r is not + + + align:start position:0% +of r the expectation value of r is not +the inverse of the expectation value of + + align:start position:0% +the inverse of the expectation value of + + + align:start position:0% +the inverse of the expectation value of +1 over r it's somewhat related but it's + + align:start position:0% +1 over r it's somewhat related but it's + + + align:start position:0% +1 over r it's somewhat related but it's +there's no theorem because it would be + + align:start position:0% +there's no theorem because it would be + + + align:start position:0% +there's no theorem because it would be +false that the expectation value of one + + align:start position:0% +false that the expectation value of one + + + align:start position:0% +false that the expectation value of one +of a random variable is the expectation + + align:start position:0% +of a random variable is the expectation + + + align:start position:0% +of a random variable is the expectation +value of its 1 over the expectation + + align:start position:0% +value of its 1 over the expectation + + + align:start position:0% +value of its 1 over the expectation +value of the random variable it's just + + align:start position:0% +value of the random variable it's just + + + align:start position:0% +value of the random variable it's just +not true this nice we solve for 1 over R + + align:start position:0% +not true this nice we solve for 1 over R + + + align:start position:0% +not true this nice we solve for 1 over R +is exactly true and it's L independent + + align:start position:0% +is exactly true and it's L independent + + + align:start position:0% +is exactly true and it's L independent +on the other hand the expectation value + + align:start position:0% +on the other hand the expectation value + + + align:start position:0% +on the other hand the expectation value +of R can be calculated with a bit more + + align:start position:0% +of R can be calculated with a bit more + + + align:start position:0% +of R can be calculated with a bit more +effort a lot more effort and is equal to + + align:start position:0% +effort a lot more effort and is equal to + + + align:start position:0% +effort a lot more effort and is equal to +this it's just the same thing and one + + align:start position:0% +this it's just the same thing and one + + + align:start position:0% +this it's just the same thing and one +with a little correction which is 1/2 1 + + align:start position:0% +with a little correction which is 1/2 1 + + + align:start position:0% +with a little correction which is 1/2 1 +minus L times L plus 1 over N squared so + + align:start position:0% +minus L times L plus 1 over N squared so + + + align:start position:0% +minus L times L plus 1 over N squared so +actually the expectation value of R in + + align:start position:0% +actually the expectation value of R in + + + align:start position:0% +actually the expectation value of R in +the hydrogen atom is L dependent not + + align:start position:0% +the hydrogen atom is L dependent not + + + align:start position:0% +the hydrogen atom is L dependent not +terribly strongly L dependent but + + align:start position:0% +terribly strongly L dependent but + + + align:start position:0% +terribly strongly L dependent but +somewhat L dependent to get an idea this + + align:start position:0% +somewhat L dependent to get an idea this + + + align:start position:0% +somewhat L dependent to get an idea this +is equal to N squared a + + align:start position:0% +is equal to N squared a + + + align:start position:0% +is equal to N squared a +now times three-halves for l equals zero + + align:start position:0% +now times three-halves for l equals zero + + + align:start position:0% +now times three-halves for l equals zero +when L is equal to zero you see this + + align:start position:0% +when L is equal to zero you see this + + + align:start position:0% +when L is equal to zero you see this +whole bracket becomes three-halves and + + align:start position:0% +whole bracket becomes three-halves and + + + align:start position:0% +whole bracket becomes three-halves and +for the maximum l l equals n minus 1 + + align:start position:0% +for the maximum l l equals n minus 1 + + + align:start position:0% +for the maximum l l equals n minus 1 +this is roughly 1 this is roughly 0 to a + + align:start position:0% +this is roughly 1 this is roughly 0 to a + + + align:start position:0% +this is roughly 1 this is roughly 0 to a +good approximation but not exactly + + align:start position:0% +good approximation but not exactly + + + align:start position:0% +good approximation but not exactly +becomes N squared a not with Corrections + + align:start position:0% +becomes N squared a not with Corrections + + + align:start position:0% +becomes N squared a not with Corrections +that are very very small it's pretty + + align:start position:0% +that are very very small it's pretty + + + align:start position:0% +that are very very small it's pretty +accurate all right so first thing we've + + align:start position:0% +accurate all right so first thing we've + + + align:start position:0% +accurate all right so first thing we've +learned is that we got a radius expected + + align:start position:0% +learned is that we got a radius expected + + + align:start position:0% +learned is that we got a radius expected +radius that goes like N squared a knot + + align:start position:0% +radius that goes like N squared a knot + + + align:start position:0% +radius that goes like N squared a knot +so it's kind of interesting to see what + + align:start position:0% +so it's kind of interesting to see what + + + align:start position:0% +so it's kind of interesting to see what +went wrong if you would have thought + + align:start position:0% +went wrong if you would have thought + + + align:start position:0% +went wrong if you would have thought +with this with the form of the solution + + align:start position:0% +with this with the form of the solution + + + align:start position:0% +with this with the form of the solution +so sy n L m equal a R to the L W and L a + + align:start position:0% +so sy n L m equal a R to the L W and L a + + + align:start position:0% +so sy n L m equal a R to the L W and L a +polynomial e to the minus R over N a not + + align:start position:0% +polynomial e to the minus R over N a not + + + align:start position:0% +polynomial e to the minus R over N a not +ylm of theta and Phi or F n L of our x y + + align:start position:0% +ylm of theta and Phi or F n L of our x y + + + align:start position:0% +ylm of theta and Phi or F n L of our x y +L M of the solid angle and what do we + + align:start position:0% +L M of the solid angle and what do we + + + align:start position:0% +L M of the solid angle and what do we +know about this polynomial + + align:start position:0% +know about this polynomial + + + align:start position:0% +know about this polynomial +it's of degree n minus L plus 1 that's + + align:start position:0% +it's of degree n minus L plus 1 that's + + + align:start position:0% +it's of degree n minus L plus 1 that's +it + + align:start position:0% +it + + + align:start position:0% +it +I need depends on R so so what we're + + align:start position:0% +I need depends on R so so what we're + + + align:start position:0% +I need depends on R so so what we're +looking at is what was the error in + + align:start position:0% +looking at is what was the error in + + + align:start position:0% +looking at is what was the error in +thinking that the typical r was an a + + align:start position:0% +thinking that the typical r was an a + + + align:start position:0% +thinking that the typical r was an a +naught and you see when you make a + + align:start position:0% +naught and you see when you make a + + + align:start position:0% +naught and you see when you make a +mistake like this the mistake i made of + + align:start position:0% +mistake like this the mistake i made of + + + align:start position:0% +mistake like this the mistake i made of +saying oh na naught must be right and + + align:start position:0% +saying oh na naught must be right and + + + align:start position:0% +saying oh na naught must be right and +you find that it's wrong it's very + + align:start position:0% +you find that it's wrong it's very + + + align:start position:0% +you find that it's wrong it's very +important to go back and learn why did + + align:start position:0% +important to go back and learn why did + + + align:start position:0% +important to go back and learn why did +you get the wrong hands + + align:start position:0% +you get the wrong hands + + + align:start position:0% +you get the wrong hands +that's what we're doing now so the one + + align:start position:0% +that's what we're doing now so the one + + + align:start position:0% +that's what we're doing now so the one +question I can ask to begin with is what + + align:start position:0% +question I can ask to begin with is what + + + align:start position:0% +question I can ask to begin with is what +is a probability density to find the + + align:start position:0% +is a probability density to find the + + + align:start position:0% +is a probability density to find the +electron between some radius R and a + + align:start position:0% +electron between some radius R and a + + + align:start position:0% +electron between some radius R and a +radius R Plus D R so you know this is a + + align:start position:0% +radius R Plus D R so you know this is a + + + align:start position:0% +radius R Plus D R so you know this is a +probability and it depends on theta and + + align:start position:0% +probability and it depends on theta and + + + align:start position:0% +probability and it depends on theta and +Phi and it's very complicated how about + + align:start position:0% +Phi and it's very complicated how about + + + align:start position:0% +Phi and it's very complicated how about +giving me a probability along R that I + + align:start position:0% +giving me a probability along R that I + + + align:start position:0% +giving me a probability along R that I +can integrate along R and visualize how + + align:start position:0% +can integrate along R and visualize how + + + align:start position:0% +can integrate along R and visualize how +does it depend on R so the probability + + align:start position:0% +does it depend on R so the probability + + + align:start position:0% +does it depend on R so the probability +to find the electron in this shell must + + align:start position:0% +to find the electron in this shell must + + + align:start position:0% +to find the electron in this shell must +be equal to the value of the wave + + align:start position:0% +be equal to the value of the wave + + + align:start position:0% +be equal to the value of the wave +function squared times the volume + + align:start position:0% +function squared times the volume + + + align:start position:0% +function squared times the volume +element and the volume element here is + + align:start position:0% +element and the volume element here is + + + align:start position:0% +element and the volume element here is +PI squared R squared the R times you + + align:start position:0% +PI squared R squared the R times you + + + align:start position:0% +PI squared R squared the R times you +would say 4 pi but it's not spherically + + align:start position:0% +would say 4 pi but it's not spherically + + + align:start position:0% +would say 4 pi but it's not spherically +symmetric so you have to integrate oops + + align:start position:0% +symmetric so you have to integrate oops + + + align:start position:0% +symmetric so you have to integrate oops +you have to integrate over solid angle + + align:start position:0% +you have to integrate over solid angle + + + align:start position:0% +you have to integrate over solid angle +that is the volume elements and since + + align:start position:0% +that is the volume elements and since + + + align:start position:0% +that is the volume elements and since +they have to integrate over solid angle + + align:start position:0% +they have to integrate over solid angle + + + align:start position:0% +they have to integrate over solid angle +I must have size squared here so that's + + align:start position:0% +I must have size squared here so that's + + + align:start position:0% +I must have size squared here so that's +the right equation they if you want to + + align:start position:0% +the right equation they if you want to + + + align:start position:0% +the right equation they if you want to +make things look perfect put the D cube + + align:start position:0% +make things look perfect put the D cube + + + align:start position:0% +make things look perfect put the D cube +X before at the size squared here and + + align:start position:0% +X before at the size squared here and + + + align:start position:0% +X before at the size squared here and +the problem is that the d cube x is big + + align:start position:0% +the problem is that the d cube x is big + + + align:start position:0% +the problem is that the d cube x is big +enough that it some sense has a partial + + align:start position:0% +enough that it some sense has a partial + + + align:start position:0% +enough that it some sense has a partial +integral so notation is not perfect but + + align:start position:0% +integral so notation is not perfect but + + + align:start position:0% +integral so notation is not perfect but +somehow you must imagine this whole + + align:start position:0% +somehow you must imagine this whole + + + align:start position:0% +somehow you must imagine this whole +volume element that is still + + align:start position:0% +volume element that is still + + + align:start position:0% +volume element that is still +infinitesimally involves some integral + + align:start position:0% +infinitesimally involves some integral + + + align:start position:0% +infinitesimally involves some integral +already so you have this and you get + + align:start position:0% +already so you have this and you get + + + align:start position:0% +already so you have this and you get +that r squared d r f n l squared + + align:start position:0% +that r squared d r f n l squared + + + align:start position:0% +that r squared d r f n l squared +and you have the integral the Omega of + + align:start position:0% +and you have the integral the Omega of + + + align:start position:0% +and you have the integral the Omega of +this Y star LM y LM ad that integral is + + align:start position:0% +this Y star LM y LM ad that integral is + + + align:start position:0% +this Y star LM y LM ad that integral is +exactly one spherical harmonics are + + align:start position:0% +exactly one spherical harmonics are + + + align:start position:0% +exactly one spherical harmonics are +normalized so now I can cancel the dr + + align:start position:0% +normalized so now I can cancel the dr + + + align:start position:0% +normalized so now I can cancel the dr +and i get that the radial probability + + align:start position:0% +and i get that the radial probability + + + align:start position:0% +and i get that the radial probability +distribution which is a nice concept is + + align:start position:0% +distribution which is a nice concept is + + + align:start position:0% +distribution which is a nice concept is +really R squared f NL of R squared + + align:start position:0% + + + + align:start position:0% + +radial probability so our mistake my + + align:start position:0% +radial probability so our mistake my + + + align:start position:0% +radial probability so our mistake my +mistake must have been that I didn't + + align:start position:0% +mistake must have been that I didn't + + + align:start position:0% +mistake must have been that I didn't +include all that was relevant the + + align:start position:0% +include all that was relevant the + + + align:start position:0% +include all that was relevant the +exponential is one part but there is the + + align:start position:0% +exponential is one part but there is the + + + align:start position:0% +exponential is one part but there is the +polynomial and the polynomial must be + + align:start position:0% +polynomial and the polynomial must be + + + align:start position:0% +polynomial and the polynomial must be +causing the trouble indeed that's what + + align:start position:0% +causing the trouble indeed that's what + + + align:start position:0% +causing the trouble indeed that's what +is happening let's look at FML from the + + align:start position:0% +is happening let's look at FML from the + + + align:start position:0% +is happening let's look at FML from the +top blackboard that includes R to the L + + align:start position:0% +top blackboard that includes R to the L + + + align:start position:0% +top blackboard that includes R to the L +times at polynomial and it's a + + align:start position:0% +times at polynomial and it's a + + + align:start position:0% +times at polynomial and it's a +polynomial of that degree so it begins + + align:start position:0% +polynomial of that degree so it begins + + + align:start position:0% +polynomial of that degree so it begins +like a not plus up to coefficient a + + align:start position:0% +like a not plus up to coefficient a + + + align:start position:0% +like a not plus up to coefficient a +prime R to the n minus L plus L minus L + + align:start position:0% +prime R to the n minus L plus L minus L + + + align:start position:0% +prime R to the n minus L plus L minus L +minus one and then I have exponential + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now I cannot do this I don't want to do + + align:start position:0% +now I cannot do this I don't want to do + + + align:start position:0% +now I cannot do this I don't want to do +this calculation exactly it's too + + align:start position:0% +this calculation exactly it's too + + + align:start position:0% +this calculation exactly it's too +complicated + + align:start position:0% +complicated + + + align:start position:0% +complicated +so let's ignore the lower parts of the + + align:start position:0% +so let's ignore the lower parts of the + + + align:start position:0% +so let's ignore the lower parts of the +polynomial and we're thinking the radius + + align:start position:0% +polynomial and we're thinking the radius + + + align:start position:0% +polynomial and we're thinking the radius +is going to be reasonably big so it's a + + align:start position:0% +is going to be reasonably big so it's a + + + align:start position:0% +is going to be reasonably big so it's a +reasonable idea to keep the power of the + + align:start position:0% +reasonable idea to keep the power of the + + + align:start position:0% +reasonable idea to keep the power of the +polynomial that is the largest so what + + align:start position:0% +polynomial that is the largest so what + + + align:start position:0% +polynomial that is the largest so what +is the largest and here you see a nice + + align:start position:0% +is the largest and here you see a nice + + + align:start position:0% +is the largest and here you see a nice +thing actually R to the L times this + + align:start position:0% +thing actually R to the L times this + + + align:start position:0% +thing actually R to the L times this +polynomial is a polynomial that begins + + align:start position:0% +polynomial is a polynomial that begins + + + align:start position:0% +polynomial is a polynomial that begins +with R to the L and finishes with R to + + align:start position:0% +with R to the L and finishes with R to + + + align:start position:0% +with R to the L and finishes with R to +the N minus 1 so it has like equal + + align:start position:0% +the N minus 1 so it has like equal + + + align:start position:0% +the N minus 1 so it has like equal +number of terms as reaches a value of n + + align:start position:0% +number of terms as reaches a value of n + + + align:start position:0% +number of terms as reaches a value of n +minus 1 the last term in the polynomial + + align:start position:0% +minus 1 the last term in the polynomial + + + align:start position:0% +minus 1 the last term in the polynomial +when you multiply it in this begins like + + align:start position:0% +when you multiply it in this begins like + + + align:start position:0% +when you multiply it in this begins like +R to the L and the last term is R to the + + align:start position:0% +R to the L and the last term is R to the + + + align:start position:0% +R to the L and the last term is R to the +N minus 1 so let's take this to be + + align:start position:0% +N minus 1 so let's take this to be + + + align:start position:0% +N minus 1 so let's take this to be +proportional to R to the N minus 1 equal + + align:start position:0% +proportional to R to the N minus 1 equal + + + align:start position:0% +proportional to R to the N minus 1 equal +to minus R and a 0 and here is the fight + + align:start position:0% +to minus R and a 0 and here is the fight + + + align:start position:0% +to minus R and a 0 and here is the fight +that actually changes the answer because + + align:start position:0% +that actually changes the answer because + + + align:start position:0% +that actually changes the answer because +this is FNL so actually I can write P of + + align:start position:0% +this is FNL so actually I can write P of + + + align:start position:0% +this is FNL so actually I can write P of +R is proportional up to a constant of + + align:start position:0% +R is proportional up to a constant of + + + align:start position:0% +R is proportional up to a constant of +normalization and and the approximations + + align:start position:0% +normalization and and the approximations + + + align:start position:0% +normalization and and the approximations +they have done R squared times this + + align:start position:0% +they have done R squared times this + + + align:start position:0% +they have done R squared times this +polynomial squared but I'm taking the + + align:start position:0% +polynomial squared but I'm taking the + + + align:start position:0% +polynomial squared but I'm taking the +last term of the polynomial so we get R + + align:start position:0% +last term of the polynomial so we get R + + + align:start position:0% +last term of the polynomial so we get R +to the 2n e to the minus 2 R over m a + + align:start position:0% +to the 2n e to the minus 2 R over m a + + + align:start position:0% +to the 2n e to the minus 2 R over m a +naught that's a probability distribution + + align:start position:0% +naught that's a probability distribution + + + align:start position:0% +naught that's a probability distribution +and with this probability distribution + + align:start position:0% +and with this probability distribution + + + align:start position:0% +and with this probability distribution +then you see what's happening is that + + align:start position:0% +then you see what's happening is that + + + align:start position:0% +then you see what's happening is that +there is a fight between an exponential + + align:start position:0% +there is a fight between an exponential + + + align:start position:0% +there is a fight between an exponential +that has a typical length where it + + align:start position:0% +that has a typical length where it + + + align:start position:0% +that has a typical length where it +decays to half its value that is related + + align:start position:0% +decays to half its value that is related + + + align:start position:0% +decays to half its value that is related +to n + + align:start position:0% +to n + + + align:start position:0% +to n +but the maximum is delay because it's + + align:start position:0% +but the maximum is delay because it's + + + align:start position:0% +but the maximum is delay because it's +multiplied by a function that they've + + align:start position:0% +multiplied by a function that they've + + + align:start position:0% +multiplied by a function that they've +higher the value of n the slower it is + + align:start position:0% +higher the value of n the slower it is + + + align:start position:0% +higher the value of n the slower it is +to take off x squared or R squared takes + + align:start position:0% +to take off x squared or R squared takes + + + align:start position:0% +to take off x squared or R squared takes +off slower than R takes off slower than + + align:start position:0% +off slower than R takes off slower than + + + align:start position:0% +off slower than R takes off slower than +R to the fourth so the pro so here you + + align:start position:0% +R to the fourth so the pro so here you + + + align:start position:0% +R to the fourth so the pro so here you +have a thing that just grows like that + + align:start position:0% +have a thing that just grows like that + + + align:start position:0% +have a thing that just grows like that +but it takes forever to take off and the + + align:start position:0% +but it takes forever to take off and the + + + align:start position:0% +but it takes forever to take off and the +result of this is a function that just + + align:start position:0% +result of this is a function that just + + + align:start position:0% +result of this is a function that just +picks up at some point over here and we + + align:start position:0% +picks up at some point over here and we + + + align:start position:0% +picks up at some point over here and we +want to find the maximum so the maximum + + align:start position:0% +want to find the maximum so the maximum + + + align:start position:0% +want to find the maximum so the maximum +comes from taking a derivative so the + + align:start position:0% +comes from taking a derivative so the + + + align:start position:0% +comes from taking a derivative so the +maximum of P of R is determined by + + align:start position:0% +maximum of P of R is determined by + + + align:start position:0% +maximum of P of R is determined by +setting the derivative of this equal to + + align:start position:0% +setting the derivative of this equal to + + + align:start position:0% +setting the derivative of this equal to +zero so you get 2 n over R times the + + align:start position:0% +zero so you get 2 n over R times the + + + align:start position:0% +zero so you get 2 n over R times the +same R to the 2n e to the minus 2 R over + + align:start position:0% +same R to the 2n e to the minus 2 R over + + + align:start position:0% +same R to the 2n e to the minus 2 R over +m a naught so the first term the + + align:start position:0% +m a naught so the first term the + + + align:start position:0% +m a naught so the first term the +derivative is 2 R and R to the 2n minus + + align:start position:0% +derivative is 2 R and R to the 2n minus + + + align:start position:0% +derivative is 2 R and R to the 2n minus +1 which is divided by R and the same + + align:start position:0% +1 which is divided by R and the same + + + align:start position:0% +1 which is divided by R and the same +thing the second derivative gives you + + align:start position:0% +thing the second derivative gives you + + + align:start position:0% +thing the second derivative gives you +minus 2 over n a naught and that's it + + align:start position:0% +minus 2 over n a naught and that's it + + + align:start position:0% +minus 2 over n a naught and that's it +so from this two you get that M over R + + align:start position:0% +so from this two you get that M over R + + + align:start position:0% +so from this two you get that M over R +is equal to 1 over M naught so R equals + + align:start position:0% +is equal to 1 over M naught so R equals + + + align:start position:0% +is equal to 1 over M naught so R equals +N squared a naught as we had predicted + + align:start position:0% +N squared a naught as we had predicted + + + align:start position:0% +N squared a naught as we had predicted +so it's the interplay of the polynomial + + align:start position:0% +so it's the interplay of the polynomial + + + align:start position:0% +so it's the interplay of the polynomial +with the other thing that makes the + + align:start position:0% +with the other thing that makes the + + + align:start position:0% +with the other thing that makes the +radius + + align:start position:0% +radius + + + align:start position:0% +radius +go very high so what about this red burg + + align:start position:0% +go very high so what about this red burg + + + align:start position:0% +go very high so what about this red burg +atoms in nature well they've been + + align:start position:0% +atoms in nature well they've been + + + align:start position:0% +atoms in nature well they've been +observed in + + align:start position:0% +observed in + + + align:start position:0% +observed in +interstellar gaseous if you see there + + align:start position:0% +interstellar gaseous if you see there + + + align:start position:0% +interstellar gaseous if you see there +was this phenomenon of recombination + + align:start position:0% +was this phenomenon of recombination + + + align:start position:0% +was this phenomenon of recombination +when protons captured electrons as the + + align:start position:0% +when protons captured electrons as the + + + align:start position:0% +when protons captured electrons as the +universe cooled off and form hydrogen + + align:start position:0% +universe cooled off and form hydrogen + + + align:start position:0% +universe cooled off and form hydrogen +atoms and that recombination sometimes + + align:start position:0% +atoms and that recombination sometimes + + + align:start position:0% +atoms and that recombination sometimes +works in such a way that the proton can + + align:start position:0% +works in such a way that the proton can + + + align:start position:0% +works in such a way that the proton can +capture an electron and it captures it + + align:start position:0% +capture an electron and it captures it + + + align:start position:0% +capture an electron and it captures it +in a very high quantum number and it + + align:start position:0% +in a very high quantum number and it + + + align:start position:0% +in a very high quantum number and it +keeps happening as we observe this + + align:start position:0% +keeps happening as we observe this + + + align:start position:0% +keeps happening as we observe this +electron so so people have observed in + + align:start position:0% +electron so so people have observed in + + + align:start position:0% +electron so so people have observed in +astrophysics n equal 350 and proto here + + align:start position:0% +astrophysics n equal 350 and proto here + + + align:start position:0% +astrophysics n equal 350 and proto here +the electron beam captured just not in + + align:start position:0% +the electron beam captured just not in + + + align:start position:0% +the electron beam captured just not in +the usual size but almost a million + + align:start position:0% +the usual size but almost a million + + + align:start position:0% +the usual size but almost a million +times bigger so what happens for this + + align:start position:0% +times bigger so what happens for this + + + align:start position:0% +times bigger so what happens for this +thing R is equal 0.53 times 10 to the + + align:start position:0% +thing R is equal 0.53 times 10 to the + + + align:start position:0% +thing R is equal 0.53 times 10 to the +minus 10 meters that's a zero and then + + align:start position:0% +minus 10 meters that's a zero and then + + + align:start position:0% +minus 10 meters that's a zero and then +you have 350 squared and that gives you + + align:start position:0% +you have 350 squared and that gives you + + + align:start position:0% +you have 350 squared and that gives you +six point five microns that's actually + + align:start position:0% +six point five microns that's actually + + + align:start position:0% +six point five microns that's actually +pretty big a blood cell is eight microns + + align:start position:0% +pretty big a blood cell is eight microns + + + align:start position:0% +pretty big a blood cell is eight microns +red blood cell is eighth microns they + + align:start position:0% +red blood cell is eighth microns they + + + align:start position:0% +red blood cell is eighth microns they +are not stable because eventually they + + align:start position:0% +are not stable because eventually they + + + align:start position:0% +are not stable because eventually they +spiral in but if you had a if you have + + align:start position:0% +spiral in but if you had a if you have + + + align:start position:0% +spiral in but if you had a if you have +an atom that for example has an N equal + + align:start position:0% +an atom that for example has an N equal + + + align:start position:0% +an atom that for example has an N equal +to five it jumps to N equals to one in + + align:start position:0% +to five it jumps to N equals to one in + + + align:start position:0% +to five it jumps to N equals to one in +ten to the minus seven seconds these + + align:start position:0% +ten to the minus seven seconds these + + + align:start position:0% +ten to the minus seven seconds these +atoms are rather stable instead of + + align:start position:0% +atoms are rather stable instead of + + + align:start position:0% +atoms are rather stable instead of +lasting one tenth of a million of a + + align:start position:0% +lasting one tenth of a million of a + + + align:start position:0% +lasting one tenth of a million of a +second they can last a millisecond a + + align:start position:0% +second they can last a millisecond a + + + align:start position:0% +second they can last a millisecond a +tenth of a second sometimes even one + + align:start position:0% +tenth of a second sometimes even one + + + align:start position:0% +tenth of a second sometimes even one +second if it takes a long time to go + + align:start position:0% +second if it takes a long time to go + + + align:start position:0% +second if it takes a long time to go +down that spiral the energy levels if + + align:start position:0% +down that spiral the energy levels if + + + align:start position:0% +down that spiral the energy levels if +you have energies that go like 1 over N + + align:start position:0% +you have energies that go like 1 over N + + + align:start position:0% +you have energies that go like 1 over N +squared the energy levels the separation + + align:start position:0% +squared the energy levels the separation + + + align:start position:0% +squared the energy levels the separation +between them goes like 1 over n cubed so + + align:start position:0% +between them goes like 1 over n cubed so + + + align:start position:0% +between them goes like 1 over n cubed so +lots and lots of states there and it + + align:start position:0% +lots and lots of states there and it + + + align:start position:0% +lots and lots of states there and it +takes a long time for it to decay from + + align:start position:0% +takes a long time for it to decay from + + + align:start position:0% +takes a long time for it to decay from +one to another + + align:start position:0% +one to another + + + align:start position:0% +one to another +oh so they observe them in the lab in + + align:start position:0% +oh so they observe them in the lab in + + + align:start position:0% +oh so they observe them in the lab in +different ways they create them with + + align:start position:0% +different ways they create them with + + + align:start position:0% +different ways they create them with +lasers now you have the Elector busted + + align:start position:0% +lasers now you have the Elector busted + + + align:start position:0% +lasers now you have the Elector busted +later you kick it to another orbit with + + align:start position:0% +later you kick it to another orbit with + + + align:start position:0% +later you kick it to another orbit with +one we use three lasers in the lab at + + align:start position:0% +one we use three lasers in the lab at + + + align:start position:0% +one we use three lasers in the lab at +MIT three lasers + + align:start position:0% +MIT three lasers + + + align:start position:0% +MIT three lasers +one and two to kick it to an N equal ten + + align:start position:0% +one and two to kick it to an N equal ten + + + align:start position:0% +one and two to kick it to an N equal ten +and then the third one to kick it to n + + align:start position:0% +and then the third one to kick it to n + + + align:start position:0% +and then the third one to kick it to n +equal 60 and they detect those atoms by + + align:start position:0% +equal 60 and they detect those atoms by + + + align:start position:0% +equal 60 and they detect those atoms by +ionization a normal atom + + align:start position:0% +ionization a normal atom + + + align:start position:0% +ionization a normal atom +you can't ionize you within millions of + + align:start position:0% +you can't ionize you within millions of + + + align:start position:0% +you can't ionize you within millions of +volts per centimeter to ionize it with + + align:start position:0% +volts per centimeter to ionize it with + + + align:start position:0% +volts per centimeter to ionize it with +an electric field these atoms you can + + align:start position:0% +an electric field these atoms you can + + + align:start position:0% +an electric field these atoms you can +ionize very easily so they can see that + + align:start position:0% +ionize very easily so they can see that + + + align:start position:0% +ionize very easily so they can see that +they've been created that way so also in + + align:start position:0% +they've been created that way so also in + + + align:start position:0% +they've been created that way so also in +terms of sizes the diameter of hair of + + align:start position:0% +terms of sizes the diameter of hair of + + + align:start position:0% +terms of sizes the diameter of hair of +hair is about 50 microns if their hair + + align:start position:0% +hair is about 50 microns if their hair + + + align:start position:0% +hair is about 50 microns if their hair +is very thin but you see it so you're + + align:start position:0% +is very thin but you see it so you're + + + align:start position:0% +is very thin but you see it so you're +about a factor of five or ten to being + + align:start position:0% +about a factor of five or ten to being + + + align:start position:0% +about a factor of five or ten to being +able to see that atom with your naked + + align:start position:0% +able to see that atom with your naked + + + align:start position:0% +able to see that atom with your naked +eye it's pretty impressive incredible in + + align:start position:0% +eye it's pretty impressive incredible in + + + align:start position:0% +eye it's pretty impressive incredible in +fact so a nice laboratory those are + + align:start position:0% +fact so a nice laboratory those are + + + align:start position:0% +fact so a nice laboratory those are +almost semi-classical atoms all what + + align:start position:0% +almost semi-classical atoms all what + + + align:start position:0% +almost semi-classical atoms all what +Bohr was doing of calculated you can + + align:start position:0% +Bohr was doing of calculated you can + + + align:start position:0% +Bohr was doing of calculated you can +derive this law by assuming that the + + align:start position:0% +derive this law by assuming that the + + + align:start position:0% +derive this law by assuming that the +transitions between orbits in the + + align:start position:0% +transitions between orbits in the + + + align:start position:0% +transitions between orbits in the +hydrogen atom and MIT photos of the + + align:start position:0% +hydrogen atom and MIT photos of the + + + align:start position:0% +hydrogen atom and MIT photos of the +right frequency it's all kinds of fun + + align:start position:0% +right frequency it's all kinds of fun + + + align:start position:0% +right frequency it's all kinds of fun +things \ No newline at end of file diff --git a/b3szQPSRfjY.txt b/b3szQPSRfjY.txt new file mode 100644 index 0000000000000000000000000000000000000000..61087cea6aaaa81d79c060870625429151ce4999 --- /dev/null +++ b/b3szQPSRfjY.txt @@ -0,0 +1,2763 @@ +align:start position:0% + +the person who sort of invents a new + + align:start position:0% +the person who sort of invents a new + + + align:start position:0% +the person who sort of invents a new +sustainable + + align:start position:0% +sustainable + + + align:start position:0% +sustainable +energy source or figures out how to + + align:start position:0% +energy source or figures out how to + + + align:start position:0% +energy source or figures out how to +remove plastics from the ocean + + align:start position:0% +remove plastics from the ocean + + + align:start position:0% +remove plastics from the ocean +it doesn't matter whether they have a + + align:start position:0% +it doesn't matter whether they have a + + + align:start position:0% +it doesn't matter whether they have a +degree or a certificate what matters is + + align:start position:0% +degree or a certificate what matters is + + + align:start position:0% +degree or a certificate what matters is +can they actually achieve it + + align:start position:0% +can they actually achieve it + + + align:start position:0% +can they actually achieve it +that i think is what we need to keep our + + align:start position:0% +that i think is what we need to keep our + + + align:start position:0% +that i think is what we need to keep our +eye on which is can they solve the + + align:start position:0% +eye on which is can they solve the + + + align:start position:0% +eye on which is can they solve the +problem + + align:start position:0% +problem + + + align:start position:0% +problem +today on chalk radio we're sitting down + + align:start position:0% +today on chalk radio we're sitting down + + + align:start position:0% +today on chalk radio we're sitting down +with sanjay sarma the vice president for + + align:start position:0% +with sanjay sarma the vice president for + + + align:start position:0% +with sanjay sarma the vice president for +open learning at mit + + align:start position:0% +open learning at mit + + + align:start position:0% +open learning at mit +sanjay wears many hats he's a professor + + align:start position:0% +sanjay wears many hats he's a professor + + + align:start position:0% +sanjay wears many hats he's a professor +of mechanical engineering a developer + + align:start position:0% +of mechanical engineering a developer + + + align:start position:0% +of mechanical engineering a developer +writer a parent and perhaps most salient + + align:start position:0% +writer a parent and perhaps most salient + + + align:start position:0% +writer a parent and perhaps most salient +for us at mit open courseware + + align:start position:0% +for us at mit open courseware + + + align:start position:0% +for us at mit open courseware +sanjay is a learner + + align:start position:0% +sanjay is a learner + + + align:start position:0% +sanjay is a learner +in today's episode sanji talks to us + + align:start position:0% +in today's episode sanji talks to us + + + align:start position:0% +in today's episode sanji talks to us +about learning from the social systems + + align:start position:0% +about learning from the social systems + + + align:start position:0% +about learning from the social systems +behind how we learn to the biology of + + align:start position:0% +behind how we learn to the biology of + + + align:start position:0% +behind how we learn to the biology of +how we're wired to make sense of the + + align:start position:0% +how we're wired to make sense of the + + + align:start position:0% +how we're wired to make sense of the +world around us + + align:start position:0% +world around us + + + align:start position:0% +world around us +i'm your host sarah hansen + + align:start position:0% + + + + align:start position:0% + +in august of 2020 sanji released his + + align:start position:0% +in august of 2020 sanji released his + + + align:start position:0% +in august of 2020 sanji released his +book grasp the science transforming how + + align:start position:0% +book grasp the science transforming how + + + align:start position:0% +book grasp the science transforming how +we learn + + align:start position:0% +we learn + + + align:start position:0% +we learn +which he co-authored with luke yokinto + + align:start position:0% +which he co-authored with luke yokinto + + + align:start position:0% +which he co-authored with luke yokinto +it's about how we learn it's an attempt + + align:start position:0% +it's about how we learn it's an attempt + + + align:start position:0% +it's about how we learn it's an attempt +to describe how we learn with sort of a + + align:start position:0% +to describe how we learn with sort of a + + + align:start position:0% +to describe how we learn with sort of a +biographical aspect to it + + align:start position:0% +biographical aspect to it + + + align:start position:0% +biographical aspect to it +you know some ask me why is it called + + align:start position:0% +you know some ask me why is it called + + + align:start position:0% +you know some ask me why is it called +grasp + + align:start position:0% +grasp + + + align:start position:0% +grasp +right why grasp think about in english + + align:start position:0% +right why grasp think about in english + + + align:start position:0% +right why grasp think about in english +when you really get something called + + align:start position:0% +when you really get something called + + + align:start position:0% +when you really get something called +grasping something + + align:start position:0% +grasping something + + + align:start position:0% +grasping something +i think the german word is similar + + align:start position:0% +i think the german word is similar + + + align:start position:0% +i think the german word is similar +comprehension it has the word apprehend + + align:start position:0% +comprehension it has the word apprehend + + + align:start position:0% +comprehension it has the word apprehend +you know you apprehend someone right + + align:start position:0% +you know you apprehend someone right + + + align:start position:0% +you know you apprehend someone right +it's grabbing + + align:start position:0% +it's grabbing + + + align:start position:0% +it's grabbing +in hindi which is one of the languages i + + align:start position:0% +in hindi which is one of the languages i + + + align:start position:0% +in hindi which is one of the languages i +grew up with + + align:start position:0% +grew up with + + + align:start position:0% +grew up with +you also use a similar word which is i + + align:start position:0% +you also use a similar word which is i + + + align:start position:0% +you also use a similar word which is i +really got the concept you grab it right + + align:start position:0% +really got the concept you grab it right + + + align:start position:0% +really got the concept you grab it right +so what does it really mean to learn + + align:start position:0% +so what does it really mean to learn + + + align:start position:0% +so what does it really mean to learn +that's what this book is about and what + + align:start position:0% +that's what this book is about and what + + + align:start position:0% +that's what this book is about and what +is the science behind it how does + + align:start position:0% +is the science behind it how does + + + align:start position:0% +is the science behind it how does +curiosity drive it what does it mean to + + align:start position:0% +curiosity drive it what does it mean to + + + align:start position:0% +curiosity drive it what does it mean to +memorize something what does it mean to + + align:start position:0% +memorize something what does it mean to + + + align:start position:0% +memorize something what does it mean to +forget something + + align:start position:0% +forget something + + + align:start position:0% +forget something +what does it mean when you actually + + align:start position:0% +what does it mean when you actually + + + align:start position:0% +what does it mean when you actually +remember something but you can't access + + align:start position:0% +remember something but you can't access + + + align:start position:0% +remember something but you can't access +it but when you get it once you access + + align:start position:0% +it but when you get it once you access + + + align:start position:0% +it but when you get it once you access +it it also comes flowing out so that's + + align:start position:0% +it it also comes flowing out so that's + + + align:start position:0% +it it also comes flowing out so that's +what this book is about and it tries to + + align:start position:0% +what this book is about and it tries to + + + align:start position:0% +what this book is about and it tries to +map it from neurons all the way to + + align:start position:0% +map it from neurons all the way to + + + align:start position:0% +map it from neurons all the way to +societal level + + align:start position:0% +societal level + + + align:start position:0% +societal level +so what prompted him to write the book + + align:start position:0% +so what prompted him to write the book + + + align:start position:0% +so what prompted him to write the book +for sanjay it was about uncovering the + + align:start position:0% +for sanjay it was about uncovering the + + + align:start position:0% +for sanjay it was about uncovering the +history of schooling and rethinking the + + align:start position:0% +history of schooling and rethinking the + + + align:start position:0% +history of schooling and rethinking the +methods we used to teach + + align:start position:0% +methods we used to teach + + + align:start position:0% +methods we used to teach +i always wondered why we ended up doing + + align:start position:0% +i always wondered why we ended up doing + + + align:start position:0% +i always wondered why we ended up doing +things the way we do and it turns out + + align:start position:0% +things the way we do and it turns out + + + align:start position:0% +things the way we do and it turns out +that a lot of it is happenstance + + align:start position:0% +that a lot of it is happenstance + + + align:start position:0% +that a lot of it is happenstance +and perhaps a historical accident the + + align:start position:0% +and perhaps a historical accident the + + + align:start position:0% +and perhaps a historical accident the +impact of + + align:start position:0% +impact of + + + align:start position:0% +impact of +what we were trying to educate people + + align:start position:0% +what we were trying to educate people + + + align:start position:0% +what we were trying to educate people +about which initially was religious + + align:start position:0% +about which initially was religious + + + align:start position:0% +about which initially was religious +books right and eventually it was + + align:start position:0% +books right and eventually it was + + + align:start position:0% +books right and eventually it was +memorizing aspects of the book and there + + align:start position:0% +memorizing aspects of the book and there + + + align:start position:0% +memorizing aspects of the book and there +was the greek thread that sort of wove + + align:start position:0% +was the greek thread that sort of wove + + + align:start position:0% +was the greek thread that sort of wove +into that and then the industrial + + align:start position:0% +into that and then the industrial + + + align:start position:0% +into that and then the industrial +revolution and so on + + align:start position:0% +revolution and so on + + + align:start position:0% +revolution and so on +and so the question was if you went back + + align:start position:0% +and so the question was if you went back + + + align:start position:0% +and so the question was if you went back +to the basics how would you teach and + + align:start position:0% +to the basics how would you teach and + + + align:start position:0% +to the basics how would you teach and +what would you teach + + align:start position:0% +what would you teach + + + align:start position:0% +what would you teach +i too am a product of western education + + align:start position:0% +i too am a product of western education + + + align:start position:0% +i too am a product of western education +principles and i did well but i also + + align:start position:0% +principles and i did well but i also + + + align:start position:0% +principles and i did well but i also +struggled + + align:start position:0% +struggled + + + align:start position:0% +struggled +and so i started wondering what the + + align:start position:0% +and so i started wondering what the + + + align:start position:0% +and so i started wondering what the +science tells us about how educational + + align:start position:0% +science tells us about how educational + + + align:start position:0% +science tells us about how educational +systems should be designed + + align:start position:0% +systems should be designed + + + align:start position:0% +systems should be designed +so once i started researching it i + + align:start position:0% +so once i started researching it i + + + align:start position:0% +so once i started researching it i +thought oh my god the story needs to be + + align:start position:0% +thought oh my god the story needs to be + + + align:start position:0% +thought oh my god the story needs to be +told so the book sort of started writing + + align:start position:0% +told so the book sort of started writing + + + align:start position:0% +told so the book sort of started writing +itself and then i found luke and he + + align:start position:0% +itself and then i found luke and he + + + align:start position:0% +itself and then i found luke and he +shaped it with me and that's what i like + + align:start position:0% +shaped it with me and that's what i like + + + align:start position:0% +shaped it with me and that's what i like +to grasp + + align:start position:0% +to grasp + + + align:start position:0% +to grasp +so what's the difference between simply + + align:start position:0% +so what's the difference between simply + + + align:start position:0% +so what's the difference between simply +picking up concepts and actually + + align:start position:0% +picking up concepts and actually + + + align:start position:0% +picking up concepts and actually +grasping them + + align:start position:0% +grasping them + + + align:start position:0% +grasping them +according to sanjay what it often comes + + align:start position:0% +according to sanjay what it often comes + + + align:start position:0% +according to sanjay what it often comes +down to + + align:start position:0% +down to + + + align:start position:0% +down to +is having an actionable component to + + align:start position:0% +is having an actionable component to + + + align:start position:0% +is having an actionable component to +learning + + align:start position:0% +learning + + + align:start position:0% +learning +not just hearing and regurgitating + + align:start position:0% +not just hearing and regurgitating + + + align:start position:0% +not just hearing and regurgitating +information + + align:start position:0% +information + + + align:start position:0% +information +but locking it in place by physically + + align:start position:0% +but locking it in place by physically + + + align:start position:0% +but locking it in place by physically +applying it + + align:start position:0% +applying it + + + align:start position:0% +applying it +we + + align:start position:0% +we + + + align:start position:0% +we +have this assumption that the learner's + + align:start position:0% +have this assumption that the learner's + + + align:start position:0% +have this assumption that the learner's +mind is a sheet of + + align:start position:0% +mind is a sheet of + + + align:start position:0% +mind is a sheet of +paper and the professor has a pen + + align:start position:0% +paper and the professor has a pen + + + align:start position:0% +paper and the professor has a pen +and all the professor has to do is write + + align:start position:0% +and all the professor has to do is write + + + align:start position:0% +and all the professor has to do is write +on the sheet of paper and declare + + align:start position:0% +on the sheet of paper and declare + + + align:start position:0% +on the sheet of paper and declare +victory + + align:start position:0% +victory + + + align:start position:0% +victory +and after 10 minutes 15 minutes 20 + + align:start position:0% +and after 10 minutes 15 minutes 20 + + + align:start position:0% +and after 10 minutes 15 minutes 20 +minutes + + align:start position:0% +minutes + + + align:start position:0% +minutes +if the learner isn't paying attention + + align:start position:0% +if the learner isn't paying attention + + + align:start position:0% +if the learner isn't paying attention +that's the learner's fault not a + + align:start position:0% +that's the learner's fault not a + + + align:start position:0% +that's the learner's fault not a +teacher's fault + + align:start position:0% +teacher's fault + + + align:start position:0% +teacher's fault +and that is just fundamentally wrong + + align:start position:0% +and that is just fundamentally wrong + + + align:start position:0% +and that is just fundamentally wrong +and every parent knows this by the way + + align:start position:0% +and every parent knows this by the way + + + align:start position:0% +and every parent knows this by the way +when we go to the classroom we just + + align:start position:0% +when we go to the classroom we just + + + align:start position:0% +when we go to the classroom we just +ignore that truth + + align:start position:0% +ignore that truth + + + align:start position:0% +ignore that truth +the fact is the learner is forming a + + align:start position:0% +the fact is the learner is forming a + + + align:start position:0% +the fact is the learner is forming a +model of the world + + align:start position:0% +model of the world + + + align:start position:0% +model of the world +it's like a plant growing + + align:start position:0% +it's like a plant growing + + + align:start position:0% +it's like a plant growing +you can give the plant + + align:start position:0% +you can give the plant + + + align:start position:0% +you can give the plant +a lifetime's worth of water on the first + + align:start position:0% +a lifetime's worth of water on the first + + + align:start position:0% +a lifetime's worth of water on the first +day and say you're done + + align:start position:0% +day and say you're done + + + align:start position:0% +day and say you're done +and all the potassium on day two + + align:start position:0% +and all the potassium on day two + + + align:start position:0% +and all the potassium on day two +and all the nitrogen and day three you + + align:start position:0% +and all the nitrogen and day three you + + + align:start position:0% +and all the nitrogen and day three you +can't do that + + align:start position:0% +can't do that + + + align:start position:0% +can't do that +the plant pots water or sunlight or + + align:start position:0% +the plant pots water or sunlight or + + + align:start position:0% +the plant pots water or sunlight or +a particular type of fertilizer when the + + align:start position:0% +a particular type of fertilizer when the + + + align:start position:0% +a particular type of fertilizer when the +plant wants it by the way that's called + + align:start position:0% +plant wants it by the way that's called + + + align:start position:0% +plant wants it by the way that's called +precision agriculture + + align:start position:0% +precision agriculture + + + align:start position:0% +precision agriculture +it's a field right but yet we do that + + align:start position:0% +it's a field right but yet we do that + + + align:start position:0% +it's a field right but yet we do that +human beings + + align:start position:0% +human beings + + + align:start position:0% +human beings +i'm going to teach you all the math you + + align:start position:0% +i'm going to teach you all the math you + + + align:start position:0% +i'm going to teach you all the math you +need in the first + + align:start position:0% +need in the first + + + align:start position:0% +need in the first +four months + + align:start position:0% +four months + + + align:start position:0% +four months +you should be done that's not how it + + align:start position:0% +you should be done that's not how it + + + align:start position:0% +you should be done that's not how it +works + + align:start position:0% +works + + + align:start position:0% +works +it's when you use the math that it + + align:start position:0% +it's when you use the math that it + + + align:start position:0% +it's when you use the math that it +becomes valuable + + align:start position:0% +becomes valuable + + + align:start position:0% +becomes valuable +and so + + align:start position:0% +and so + + + align:start position:0% +and so +and every classroom + + align:start position:0% +and every classroom + + + align:start position:0% +and every classroom +violates it every class violence that + + align:start position:0% +violates it every class violence that + + + align:start position:0% +violates it every class violence that +curricula violate that principle + + align:start position:0% +curricula violate that principle + + + align:start position:0% +curricula violate that principle +what marks something as something that + + align:start position:0% +what marks something as something that + + + align:start position:0% +what marks something as something that +needs to be remembered or is valuable + + align:start position:0% +needs to be remembered or is valuable + + + align:start position:0% +needs to be remembered or is valuable +well when you process it + + align:start position:0% +well when you process it + + + align:start position:0% +well when you process it +right so if you have a nice conversation + + align:start position:0% +right so if you have a nice conversation + + + align:start position:0% +right so if you have a nice conversation +with your child or your spouse you + + align:start position:0% +with your child or your spouse you + + + align:start position:0% +with your child or your spouse you +remember that + + align:start position:0% +remember that + + + align:start position:0% +remember that +right but the + + align:start position:0% +right but the + + + align:start position:0% +right but the +conversation you had uh you know sort of + + align:start position:0% +conversation you had uh you know sort of + + + align:start position:0% +conversation you had uh you know sort of +quotidian conversation about uh + + align:start position:0% +quotidian conversation about uh + + + align:start position:0% +quotidian conversation about uh +you know something you know don't forget + + align:start position:0% +you know something you know don't forget + + + align:start position:0% +you know something you know don't forget +to pay the bill or something yeah you'll + + align:start position:0% +to pay the bill or something yeah you'll + + + align:start position:0% +to pay the bill or something yeah you'll +remember that but the conversation + + align:start position:0% +remember that but the conversation + + + align:start position:0% +remember that but the conversation +itself isn't memorable + + align:start position:0% +itself isn't memorable + + + align:start position:0% +itself isn't memorable +so engagement and purpose + + align:start position:0% +so engagement and purpose + + + align:start position:0% +so engagement and purpose +flag learning + + align:start position:0% +flag learning + + + align:start position:0% +flag learning +for the brain as being valuable and they + + align:start position:0% +for the brain as being valuable and they + + + align:start position:0% +for the brain as being valuable and they +put it in a sequence that makes it + + align:start position:0% +put it in a sequence that makes it + + + align:start position:0% +put it in a sequence that makes it +actionable + + align:start position:0% +actionable + + + align:start position:0% +actionable +i've been working with sanjay for many + + align:start position:0% +i've been working with sanjay for many + + + align:start position:0% +i've been working with sanjay for many +years at mit open learning and the + + align:start position:0% +years at mit open learning and the + + + align:start position:0% +years at mit open learning and the +phrase that i hear him utter most is + + align:start position:0% +phrase that i hear him utter most is + + + align:start position:0% +phrase that i hear him utter most is +how does your idea scale + + align:start position:0% +how does your idea scale + + + align:start position:0% +how does your idea scale +i wanted to take this opportunity to ask + + align:start position:0% +i wanted to take this opportunity to ask + + + align:start position:0% +i wanted to take this opportunity to ask +him about his focus on scaling + + align:start position:0% +him about his focus on scaling + + + align:start position:0% +him about his focus on scaling +innovations and learning + + align:start position:0% +innovations and learning + + + align:start position:0% +innovations and learning +there's something about learning that is + + align:start position:0% +there's something about learning that is + + + align:start position:0% +there's something about learning that is +a human evolutionary + + align:start position:0% +a human evolutionary + + + align:start position:0% +a human evolutionary +aspect of our existence which is + + align:start position:0% +aspect of our existence which is + + + align:start position:0% +aspect of our existence which is +children learn parents teach and we keep + + align:start position:0% +children learn parents teach and we keep + + + align:start position:0% +children learn parents teach and we keep +that so as an adult i learn + + align:start position:0% +that so as an adult i learn + + + align:start position:0% +that so as an adult i learn +in similar ways to + + align:start position:0% +in similar ways to + + + align:start position:0% +in similar ways to +how i learned as a baby from my parents + + align:start position:0% +how i learned as a baby from my parents + + + align:start position:0% +how i learned as a baby from my parents +right as a child as a young person + + align:start position:0% +right as a child as a young person + + + align:start position:0% +right as a child as a young person +parenting is not scalable + + align:start position:0% +parenting is not scalable + + + align:start position:0% +parenting is not scalable +there's a reason we have + + align:start position:0% +there's a reason we have + + + align:start position:0% +there's a reason we have +few children but we give them full + + align:start position:0% +few children but we give them full + + + align:start position:0% +few children but we give them full +attention so i think our biggest + + align:start position:0% +attention so i think our biggest + + + align:start position:0% +attention so i think our biggest +challenge is + + align:start position:0% +challenge is + + + align:start position:0% +challenge is +there are lots of people lots of young + + align:start position:0% +there are lots of people lots of young + + + align:start position:0% +there are lots of people lots of young +people lots of adults in the world that + + align:start position:0% +people lots of adults in the world that + + + align:start position:0% +people lots of adults in the world that +need to learn + + align:start position:0% +need to learn + + + align:start position:0% +need to learn +and the challenge is + + align:start position:0% +and the challenge is + + + align:start position:0% +and the challenge is +can we scale what is + + align:start position:0% +can we scale what is + + + align:start position:0% +can we scale what is +very hard to scale it's sort of the most + + align:start position:0% +very hard to scale it's sort of the most + + + align:start position:0% +very hard to scale it's sort of the most +important question + + align:start position:0% +important question + + + align:start position:0% +important question +and we can only do it if we understand + + align:start position:0% +and we can only do it if we understand + + + align:start position:0% +and we can only do it if we understand +how people learn + + align:start position:0% +how people learn + + + align:start position:0% +how people learn +and understand how technology could help + + align:start position:0% +and understand how technology could help + + + align:start position:0% +and understand how technology could help +and how humans could help and how + + align:start position:0% +and how humans could help and how + + + align:start position:0% +and how humans could help and how +coaching could help + + align:start position:0% +coaching could help + + + align:start position:0% +coaching could help +but the scale of demand is so vast if we + + align:start position:0% +but the scale of demand is so vast if we + + + align:start position:0% +but the scale of demand is so vast if we +want to make an impact we got to figure + + align:start position:0% +want to make an impact we got to figure + + + align:start position:0% +want to make an impact we got to figure +out how do we scale this thing that is + + align:start position:0% +out how do we scale this thing that is + + + align:start position:0% +out how do we scale this thing that is +so difficult to scale so to me that's + + align:start position:0% +so difficult to scale so to me that's + + + align:start position:0% +so difficult to scale so to me that's +the existential question + + align:start position:0% + + + + align:start position:0% + +one of the interesting things about + + align:start position:0% +one of the interesting things about + + + align:start position:0% +one of the interesting things about +sanjay is that he's helping solve this + + align:start position:0% +sanjay is that he's helping solve this + + + align:start position:0% +sanjay is that he's helping solve this +question of scalability through online + + align:start position:0% +question of scalability through online + + + align:start position:0% +question of scalability through online +learning + + align:start position:0% +learning + + + align:start position:0% +learning +as sanji will explain in a moment + + align:start position:0% +as sanji will explain in a moment + + + align:start position:0% +as sanji will explain in a moment +online learning cuts out many of the + + align:start position:0% +online learning cuts out many of the + + + align:start position:0% +online learning cuts out many of the +characteristics of traditional classroom + + align:start position:0% +characteristics of traditional classroom + + + align:start position:0% +characteristics of traditional classroom +models such as one-way lectures and an + + align:start position:0% +models such as one-way lectures and an + + + align:start position:0% +models such as one-way lectures and an +emphasis on memorization + + align:start position:0% +emphasis on memorization + + + align:start position:0% +emphasis on memorization +so imagine you're in the desert and + + align:start position:0% +so imagine you're in the desert and + + + align:start position:0% +so imagine you're in the desert and +you're thirsty + + align:start position:0% +you're thirsty + + + align:start position:0% +you're thirsty +if i give you a glass of water which is + + align:start position:0% +if i give you a glass of water which is + + + align:start position:0% +if i give you a glass of water which is +only half full + + align:start position:0% +only half full + + + align:start position:0% +only half full +you're not gonna say oh my god it's half + + align:start position:0% +you're not gonna say oh my god it's half + + + align:start position:0% +you're not gonna say oh my god it's half +empty you're gonna say it's half full + + align:start position:0% +empty you're gonna say it's half full + + + align:start position:0% +empty you're gonna say it's half full +so for those who don't have access to + + align:start position:0% +so for those who don't have access to + + + align:start position:0% +so for those who don't have access to +learning online education + + align:start position:0% +learning online education + + + align:start position:0% +learning online education +is a glass half full + + align:start position:0% +is a glass half full + + + align:start position:0% +is a glass half full +but it's still water + + align:start position:0% +but it's still water + + + align:start position:0% +but it's still water +for those who can have residential + + align:start position:0% +for those who can have residential + + + align:start position:0% +for those who can have residential +education online learning is quite + + align:start position:0% +education online learning is quite + + + align:start position:0% +education online learning is quite +something else + + align:start position:0% +something else + + + align:start position:0% +something else +it displaces lecture time and creates a + + align:start position:0% +it displaces lecture time and creates a + + + align:start position:0% +it displaces lecture time and creates a +room for doing all the hands-on stuff + + align:start position:0% +room for doing all the hands-on stuff + + + align:start position:0% +room for doing all the hands-on stuff +that makes education + + align:start position:0% +that makes education + + + align:start position:0% +that makes education +doubly wonderful + + align:start position:0% +doubly wonderful + + + align:start position:0% +doubly wonderful +the curiosity the coaching the field + + align:start position:0% +the curiosity the coaching the field + + + align:start position:0% +the curiosity the coaching the field +trips and discussions the disputation + + align:start position:0% +trips and discussions the disputation + + + align:start position:0% +trips and discussions the disputation +the fun the joy of learning the what i + + align:start position:0% +the fun the joy of learning the what i + + + align:start position:0% +the fun the joy of learning the what i +call the magic of mit + + align:start position:0% +call the magic of mit + + + align:start position:0% +call the magic of mit +and online learning gets rid of the + + align:start position:0% +and online learning gets rid of the + + + align:start position:0% +and online learning gets rid of the +thing we waste a lot of time on which is + + align:start position:0% +thing we waste a lot of time on which is + + + align:start position:0% +thing we waste a lot of time on which is +one-way lectures + + align:start position:0% +one-way lectures + + + align:start position:0% +one-way lectures +so to me online learning has two very + + align:start position:0% +so to me online learning has two very + + + align:start position:0% +so to me online learning has two very +different purposes it's a glass + + align:start position:0% +different purposes it's a glass + + + align:start position:0% +different purposes it's a glass +half-full + + align:start position:0% +half-full + + + align:start position:0% +half-full +for those who are + + align:start position:0% +for those who are + + + align:start position:0% +for those who are +parched + + align:start position:0% +parched + + + align:start position:0% +parched +for water it's still great water + + align:start position:0% +for water it's still great water + + + align:start position:0% +for water it's still great water +so online learning it is + + align:start position:0% +so online learning it is + + + align:start position:0% +so online learning it is +something that makes in-person education + + align:start position:0% +something that makes in-person education + + + align:start position:0% +something that makes in-person education +much richer as well + + align:start position:0% +much richer as well + + + align:start position:0% +much richer as well +by leaving time to do the hands-on stuff + + align:start position:0% +by leaving time to do the hands-on stuff + + + align:start position:0% +by leaving time to do the hands-on stuff +that today is occupied by lectures so + + align:start position:0% +that today is occupied by lectures so + + + align:start position:0% +that today is occupied by lectures so +that's the flipped classroom + + align:start position:0% +that's the flipped classroom + + + align:start position:0% +that's the flipped classroom +something sanjay has helped develop at + + align:start position:0% +something sanjay has helped develop at + + + align:start position:0% +something sanjay has helped develop at +mit is the micro masters program + + align:start position:0% +mit is the micro masters program + + + align:start position:0% +mit is the micro masters program +which makes it possible for people from + + align:start position:0% +which makes it possible for people from + + + align:start position:0% +which makes it possible for people from +all over the world to earn professional + + align:start position:0% +all over the world to earn professional + + + align:start position:0% +all over the world to earn professional +and academic credentials for mit courses + + align:start position:0% +and academic credentials for mit courses + + + align:start position:0% +and academic credentials for mit courses +they take online + + align:start position:0% +they take online + + + align:start position:0% +they take online +credentials that can be applied toward + + align:start position:0% +credentials that can be applied toward + + + align:start position:0% +credentials that can be applied toward +degrees at mit and other institutions of + + align:start position:0% +degrees at mit and other institutions of + + + align:start position:0% +degrees at mit and other institutions of +higher learning + + align:start position:0% +higher learning + + + align:start position:0% +higher learning +the micromasters gets rid of the + + align:start position:0% +the micromasters gets rid of the + + + align:start position:0% +the micromasters gets rid of the +winnowing function + + align:start position:0% +winnowing function + + + align:start position:0% +winnowing function +so let me explain so how does a master's + + align:start position:0% +so let me explain so how does a master's + + + align:start position:0% +so let me explain so how does a master's +program work + + align:start position:0% +program work + + + align:start position:0% +program work +you admit someone based on + + align:start position:0% +you admit someone based on + + + align:start position:0% +you admit someone based on +letters or recommendations and scores + + align:start position:0% +letters or recommendations and scores + + + align:start position:0% +letters or recommendations and scores +letters from people you probably have + + align:start position:0% +letters from people you probably have + + + align:start position:0% +letters from people you probably have +never met schools from universities you + + align:start position:0% +never met schools from universities you + + + align:start position:0% +never met schools from universities you +haven't visited or you don't know + + align:start position:0% +haven't visited or you don't know + + + align:start position:0% +haven't visited or you don't know +admissions it's a venuing function it's + + align:start position:0% +admissions it's a venuing function it's + + + align:start position:0% +admissions it's a venuing function it's +based on such sparse information + + align:start position:0% +based on such sparse information + + + align:start position:0% +based on such sparse information +what we do with the micromasters is + + align:start position:0% +what we do with the micromasters is + + + align:start position:0% +what we do with the micromasters is +there is no admissions + + align:start position:0% +there is no admissions + + + align:start position:0% +there is no admissions +all comers are welcome it's online the + + align:start position:0% +all comers are welcome it's online the + + + align:start position:0% +all comers are welcome it's online the +incremental cost of adding a student is + + align:start position:0% +incremental cost of adding a student is + + + align:start position:0% +incremental cost of adding a student is +very low come on in take the courses + + align:start position:0% +very low come on in take the courses + + + align:start position:0% +very low come on in take the courses +finish up + + align:start position:0% +finish up + + + align:start position:0% +finish up +take the proctored exam it's not easy + + align:start position:0% +take the proctored exam it's not easy + + + align:start position:0% +take the proctored exam it's not easy +it's difficult + + align:start position:0% +it's difficult + + + align:start position:0% +it's difficult +when you finish you have a micromasters + + align:start position:0% +when you finish you have a micromasters + + + align:start position:0% +when you finish you have a micromasters +and by the way + + align:start position:0% +and by the way + + + align:start position:0% +and by the way +if you did really well + + align:start position:0% +if you did really well + + + align:start position:0% +if you did really well +when you get into school we'll give you + + align:start position:0% +when you get into school we'll give you + + + align:start position:0% +when you get into school we'll give you +credit for it so we reverse the funnel + + align:start position:0% +credit for it so we reverse the funnel + + + align:start position:0% +credit for it so we reverse the funnel +so that's what the micro master says + + align:start position:0% +so that's what the micro master says + + + align:start position:0% +so that's what the micro master says +sanji has been on this path of making + + align:start position:0% +sanji has been on this path of making + + + align:start position:0% +sanji has been on this path of making +educational materials more accessible on + + align:start position:0% +educational materials more accessible on + + + align:start position:0% +educational materials more accessible on +a large scale for over 20 years + + align:start position:0% +a large scale for over 20 years + + + align:start position:0% +a large scale for over 20 years +so i asked him what advice he has for + + align:start position:0% +so i asked him what advice he has for + + + align:start position:0% +so i asked him what advice he has for +other educators about how to engage with + + align:start position:0% +other educators about how to engage with + + + align:start position:0% +other educators about how to engage with +grasp and how to get involved with + + align:start position:0% +grasp and how to get involved with + + + align:start position:0% +grasp and how to get involved with +scaling education + + align:start position:0% +scaling education + + + align:start position:0% +scaling education +what i suggest educators do is + + align:start position:0% +what i suggest educators do is + + + align:start position:0% +what i suggest educators do is +first of all write down a wish list + + align:start position:0% +first of all write down a wish list + + + align:start position:0% +first of all write down a wish list +of what + + align:start position:0% +of what + + + align:start position:0% +of what +they would like to do what they would + + align:start position:0% +they would like to do what they would + + + align:start position:0% +they would like to do what they would +like to see in the education system how + + align:start position:0% +like to see in the education system how + + + align:start position:0% +like to see in the education system how +they do it differently and how it maps + + align:start position:0% +they do it differently and how it maps + + + align:start position:0% +they do it differently and how it maps +to how they taught their own kids or how + + align:start position:0% +to how they taught their own kids or how + + + align:start position:0% +to how they taught their own kids or how +they learned and how a good teacher + + align:start position:0% +they learned and how a good teacher + + + align:start position:0% +they learned and how a good teacher +inspired them + + align:start position:0% +inspired them + + + align:start position:0% +inspired them +you know i was involved a little bit in + + align:start position:0% +you know i was involved a little bit in + + + align:start position:0% +you know i was involved a little bit in +the creation of open courseware 20 years + + align:start position:0% +the creation of open courseware 20 years + + + align:start position:0% +the creation of open courseware 20 years +ago and when i was doing my dynamics + + align:start position:0% +ago and when i was doing my dynamics + + + align:start position:0% +ago and when i was doing my dynamics +lectures + + align:start position:0% +lectures + + + align:start position:0% +lectures +a colleague said hey can i make + + align:start position:0% +a colleague said hey can i make + + + align:start position:0% +a colleague said hey can i make +recordings because i'm picking up your + + align:start position:0% +recordings because i'm picking up your + + + align:start position:0% +recordings because i'm picking up your +course i want to see how you know the + + align:start position:0% +course i want to see how you know the + + + align:start position:0% +course i want to see how you know the +approach you take to teach it + + align:start position:0% +approach you take to teach it + + + align:start position:0% +approach you take to teach it +and so when i made the recordings i + + align:start position:0% +and so when i made the recordings i + + + align:start position:0% +and so when i made the recordings i +called up open courseway and i said look + + align:start position:0% +called up open courseway and i said look + + + align:start position:0% +called up open courseway and i said look +if it's useful to you i'd like to put + + align:start position:0% +if it's useful to you i'd like to put + + + align:start position:0% +if it's useful to you i'd like to put +them up for what it's worth you know + + align:start position:0% +them up for what it's worth you know + + + align:start position:0% +them up for what it's worth you know +because i teach dynamics differently + + align:start position:0% +because i teach dynamics differently + + + align:start position:0% +because i teach dynamics differently +and one thing led to another and just + + align:start position:0% +and one thing led to another and just + + + align:start position:0% +and one thing led to another and just +went up there and i actually think that + + align:start position:0% +went up there and i actually think that + + + align:start position:0% +went up there and i actually think that +to + + align:start position:0% +to + + + align:start position:0% +to +unself-consciously just share + + align:start position:0% +unself-consciously just share + + + align:start position:0% +unself-consciously just share +yourself is something there's something + + align:start position:0% +yourself is something there's something + + + align:start position:0% +yourself is something there's something +liberating about it frankly + + align:start position:0% +liberating about it frankly + + + align:start position:0% +liberating about it frankly +and i recommend that others try just + + align:start position:0% +and i recommend that others try just + + + align:start position:0% +and i recommend that others try just +make a youtube video of yourself doing + + align:start position:0% +make a youtube video of yourself doing + + + align:start position:0% +make a youtube video of yourself doing +something you love put it up + + align:start position:0% +something you love put it up + + + align:start position:0% +something you love put it up +and i'm sure it'll be of value to others + + align:start position:0% +and i'm sure it'll be of value to others + + + align:start position:0% +and i'm sure it'll be of value to others +making ourselves vulnerable can lead to + + align:start position:0% +making ourselves vulnerable can lead to + + + align:start position:0% +making ourselves vulnerable can lead to +something of great value for others + + align:start position:0% +something of great value for others + + + align:start position:0% +something of great value for others +it's something we see every day here at + + align:start position:0% +it's something we see every day here at + + + align:start position:0% +it's something we see every day here at +mit open courseware + + align:start position:0% +mit open courseware + + + align:start position:0% +mit open courseware +so we'd like to say a huge thank you to + + align:start position:0% +so we'd like to say a huge thank you to + + + align:start position:0% +so we'd like to say a huge thank you to +sanjay sarma and all of the mit faculty + + align:start position:0% +sanjay sarma and all of the mit faculty + + + align:start position:0% +sanjay sarma and all of the mit faculty +who not only share their teaching + + align:start position:0% +who not only share their teaching + + + align:start position:0% +who not only share their teaching +materials but also share how they teach + + align:start position:0% +materials but also share how they teach + + + align:start position:0% +materials but also share how they teach +through interviews on our website and + + align:start position:0% +through interviews on our website and + + + align:start position:0% +through interviews on our website and +through podcast episodes like this one + + align:start position:0% +through podcast episodes like this one + + + align:start position:0% +through podcast episodes like this one +you can find sanjay sarma's teaching + + align:start position:0% +you can find sanjay sarma's teaching + + + align:start position:0% +you can find sanjay sarma's teaching +materials on our mit open courseware + + align:start position:0% +materials on our mit open courseware + + + align:start position:0% +materials on our mit open courseware +website + + align:start position:0% +website + + + align:start position:0% +website +you can also pick up a copy of grasp at + + align:start position:0% +you can also pick up a copy of grasp at + + + align:start position:0% +you can also pick up a copy of grasp at +your local library or bookshop + + align:start position:0% +your local library or bookshop + + + align:start position:0% +your local library or bookshop +some other books he suggests educators + + align:start position:0% +some other books he suggests educators + + + align:start position:0% +some other books he suggests educators +pair with grasp our make it stick and + + align:start position:0% +pair with grasp our make it stick and + + + align:start position:0% +pair with grasp our make it stick and +peak the science of expertise + + align:start position:0% +peak the science of expertise + + + align:start position:0% +peak the science of expertise +and be sure to check out sanjay's latest + + align:start position:0% +and be sure to check out sanjay's latest + + + align:start position:0% +and be sure to check out sanjay's latest +book workforce education a new roadmap + + align:start position:0% +book workforce education a new roadmap + + + align:start position:0% +book workforce education a new roadmap +from mit press + + align:start position:0% +from mit press + + + align:start position:0% +from mit press +thank you so much for listening until + + align:start position:0% +thank you so much for listening until + + + align:start position:0% +thank you so much for listening until +next time signing off from cambridge + + align:start position:0% +next time signing off from cambridge + + + align:start position:0% +next time signing off from cambridge +massachusetts i'm your host sarah hansen + + align:start position:0% +massachusetts i'm your host sarah hansen + + + align:start position:0% +massachusetts i'm your host sarah hansen +from mit open courseware + + align:start position:0% +from mit open courseware + + + align:start position:0% +from mit open courseware +chalk radio's producers include myself + + align:start position:0% +chalk radio's producers include myself + + + align:start position:0% +chalk radio's producers include myself +brett pachi and dave lashansky + + align:start position:0% +brett pachi and dave lashansky + + + align:start position:0% +brett pachi and dave lashansky +scriptwriting assistants from nidhi + + align:start position:0% +scriptwriting assistants from nidhi + + + align:start position:0% +scriptwriting assistants from nidhi +shastri show notes for this episode were + + align:start position:0% +shastri show notes for this episode were + + + align:start position:0% +shastri show notes for this episode were +written by peter chipman + + align:start position:0% +written by peter chipman + + + align:start position:0% +written by peter chipman +we're funded by mit open learning and + + align:start position:0% +we're funded by mit open learning and + + + align:start position:0% +we're funded by mit open learning and +supporters like you \ No newline at end of file diff --git a/cHgbCAHQgbU.txt b/cHgbCAHQgbU.txt new file mode 100644 index 0000000000000000000000000000000000000000..262358fb70505bb28f6f5b770796f4f83bc55eb1 --- /dev/null +++ b/cHgbCAHQgbU.txt @@ -0,0 +1,363 @@ +align:start position:0% + +we have a whole series of things that we + + align:start position:0% +we have a whole series of things that we + + + align:start position:0% +we have a whole series of things that we +drill down and look at the example that + + align:start position:0% +drill down and look at the example that + + + align:start position:0% +drill down and look at the example that +you're going to see is one that worked + + align:start position:0% +you're going to see is one that worked + + + align:start position:0% +you're going to see is one that worked +well for us but yours might be different + + align:start position:0% +well for us but yours might be different + + + align:start position:0% +well for us but yours might be different +but these types of things are what + + align:start position:0% +but these types of things are what + + + align:start position:0% +but these types of things are what +you're going to see so but we as we laid + + align:start position:0% +you're going to see so but we as we laid + + + align:start position:0% +you're going to see so but we as we laid +it out we had entertainment we had uh we + + align:start position:0% +it out we had entertainment we had uh we + + + align:start position:0% +it out we had entertainment we had uh we +had the industrial designer industrial + + align:start position:0% +had the industrial designer industrial + + + align:start position:0% +had the industrial designer industrial +designer + + align:start position:0% + + + + align:start position:0% + +design I apologize for the uh hardto + + align:start position:0% +design I apologize for the uh hardto + + + align:start position:0% +design I apologize for the uh hardto +read uh writing here and so you can see + + align:start position:0% +read uh writing here and so you can see + + + align:start position:0% +read uh writing here and so you can see +um what they were doing as well + + align:start position:0% +um what they were doing as well + + + align:start position:0% +um what they were doing as well +industrial design you would have medical + + align:start position:0% +industrial design you would have medical + + + align:start position:0% +industrial design you would have medical +visualization um companies like GE had + + align:start position:0% +visualization um companies like GE had + + + align:start position:0% +visualization um companies like GE had +3D data sets that they were getting + + align:start position:0% +3D data sets that they were getting + + + align:start position:0% +3D data sets that they were getting +through CAT scans MRI or and they wanted + + align:start position:0% +through CAT scans MRI or and they wanted + + + align:start position:0% +through CAT scans MRI or and they wanted +to look at them interact with those data + + align:start position:0% +to look at them interact with those data + + + align:start position:0% +to look at them interact with those data +sets we had surgical + + align:start position:0% + + + + align:start position:0% + +simulation we also had um Computing for + + align:start position:0% +simulation we also had um Computing for + + + align:start position:0% +simulation we also had um Computing for +the blind human computer interface for + + align:start position:0% +the blind human computer interface for + + + align:start position:0% +the blind human computer interface for +nonvisual nonvisual + + align:start position:0% +nonvisual nonvisual + + + align:start position:0% +nonvisual nonvisual +comp human computer interface and for + + align:start position:0% +comp human computer interface and for + + + align:start position:0% +comp human computer interface and for +each one of these we had molecular + + align:start position:0% +each one of these we had molecular + + + align:start position:0% +each one of these we had molecular +modeling and you go we and uh assembly + + align:start position:0% +modeling and you go we and uh assembly + + + align:start position:0% +modeling and you go we and uh assembly +path planning and we even had Geo uh + + align:start position:0% +path planning and we even had Geo uh + + + align:start position:0% +path planning and we even had Geo uh +seismic analyzing seismic data all of + + align:start position:0% +seismic analyzing seismic data all of + + + align:start position:0% +seismic analyzing seismic data all of +these different ones we laid out and + + align:start position:0% +these different ones we laid out and + + + align:start position:0% +these different ones we laid out and +then we Dug Dug down in here for a + + align:start position:0% +then we Dug Dug down in here for a + + + align:start position:0% +then we Dug Dug down in here for a +matter of a week or two to understand + + align:start position:0% +matter of a week or two to understand + + + align:start position:0% +matter of a week or two to understand +what each of them were and then at that + + align:start position:0% +what each of them were and then at that + + + align:start position:0% +what each of them were and then at that +point we had a nice Market segmentation + + align:start position:0% +point we had a nice Market segmentation + + + align:start position:0% +point we had a nice Market segmentation +that we could then take a step back and + + align:start position:0% +that we could then take a step back and + + + align:start position:0% +that we could then take a step back and +take a look at and say wow those are the + + align:start position:0% +take a look at and say wow those are the + + + align:start position:0% +take a look at and say wow those are the +top opportunities which one should we go + + align:start position:0% +top opportunities which one should we go + + + align:start position:0% +top opportunities which one should we go +after this takes a lot of work I mean + + align:start position:0% +after this takes a lot of work I mean + + + align:start position:0% +after this takes a lot of work I mean +this but the work that we're going to + + align:start position:0% +this but the work that we're going to + + + align:start position:0% +this but the work that we're going to +put in up front is going to pay + + align:start position:0% +put in up front is going to pay + + + align:start position:0% +put in up front is going to pay +dividends because our team will now have + + align:start position:0% +dividends because our team will now have + + + align:start position:0% +dividends because our team will now have +had a chance to look at all the + + align:start position:0% +had a chance to look at all the + + + align:start position:0% +had a chance to look at all the +different opportunities and when we + + align:start position:0% +different opportunities and when we + + + align:start position:0% +different opportunities and when we +choose one we're going to have the + + align:start position:0% +choose one we're going to have the + + + align:start position:0% +choose one we're going to have the +highest level of confidence possible so + + align:start position:0% +highest level of confidence possible so + + + align:start position:0% +highest level of confidence possible so +that is Market segmentation with a very + + align:start position:0% +that is Market segmentation with a very + + + align:start position:0% +that is Market segmentation with a very +specific real example at sensible + + align:start position:0% +specific real example at sensible + + + align:start position:0% +specific real example at sensible +Technologies which ended up working out + + align:start position:0% +Technologies which ended up working out + + + align:start position:0% +Technologies which ended up working out +quite well for us \ No newline at end of file diff --git a/cLfyjIlu9Uw.txt b/cLfyjIlu9Uw.txt new file mode 100644 index 0000000000000000000000000000000000000000..c2e4ff3f55696eaa9b507172a2c0df4f44e05fd4 --- /dev/null +++ b/cLfyjIlu9Uw.txt @@ -0,0 +1,627 @@ +align:start position:0% + +we can't think of a more interesting and + + align:start position:0% +we can't think of a more interesting and + + + align:start position:0% +we can't think of a more interesting and +exciting time to launch this course yes + + align:start position:0% +exciting time to launch this course yes + + + align:start position:0% +exciting time to launch this course yes +there are challenges that you and your + + align:start position:0% +there are challenges that you and your + + + align:start position:0% +there are challenges that you and your +peers will face because my baby boom + + align:start position:0% +peers will face because my baby boom + + + align:start position:0% +peers will face because my baby boom +generation didn't do a great job of + + align:start position:0% +generation didn't do a great job of + + + align:start position:0% +generation didn't do a great job of +keeping our policies and practices up to + + align:start position:0% +keeping our policies and practices up to + + + align:start position:0% +keeping our policies and practices up to +date with the changing economy and the + + align:start position:0% +date with the changing economy and the + + + align:start position:0% +date with the changing economy and the +changing Workforce but at the same time + + align:start position:0% +changing Workforce but at the same time + + + align:start position:0% +changing Workforce but at the same time +we're we're in an extremely interesting + + align:start position:0% +we're we're in an extremely interesting + + + align:start position:0% +we're we're in an extremely interesting +era of innovation around the world we're + + align:start position:0% +era of innovation around the world we're + + + align:start position:0% +era of innovation around the world we're +seeing new organizations getting formed + + align:start position:0% +seeing new organizations getting formed + + + align:start position:0% +seeing new organizations getting formed +using crowdsourcing and other modern + + align:start position:0% +using crowdsourcing and other modern + + + align:start position:0% +using crowdsourcing and other modern +techniques organizations we couldn't + + align:start position:0% +techniques organizations we couldn't + + + align:start position:0% +techniques organizations we couldn't +even have imagined several years ago + + align:start position:0% +even have imagined several years ago + + + align:start position:0% +even have imagined several years ago +there are new worker advocacy + + align:start position:0% +there are new worker advocacy + + + align:start position:0% +there are new worker advocacy +organizations coming along that will + + align:start position:0% +organizations coming along that will + + + align:start position:0% +organizations coming along that will +help Empower you to find your way in the + + align:start position:0% +help Empower you to find your way in the + + + align:start position:0% +help Empower you to find your way in the +labor market there are new apps that + + align:start position:0% +labor market there are new apps that + + + align:start position:0% +labor market there are new apps that +allow you to navigate this labor market + + align:start position:0% +allow you to navigate this labor market + + + align:start position:0% +allow you to navigate this labor market +and to figure out where the good jobs + + align:start position:0% +and to figure out where the good jobs + + + align:start position:0% +and to figure out where the good jobs +are and distinguish between good and bad + + align:start position:0% +are and distinguish between good and bad + + + align:start position:0% +are and distinguish between good and bad +employers and then there are courses + + align:start position:0% +employers and then there are courses + + + align:start position:0% +employers and then there are courses +like this exploding all around our + + align:start position:0% +like this exploding all around our + + + align:start position:0% +like this exploding all around our +universities here in the United States + + align:start position:0% +universities here in the United States + + + align:start position:0% +universities here in the United States +and in other countries We rise and fall + + align:start position:0% +and in other countries We rise and fall + + + align:start position:0% +and in other countries We rise and fall +on the strength of our middle class + + align:start position:0% +on the strength of our middle class + + + align:start position:0% +on the strength of our middle class +these online courses allow you to gain + + align:start position:0% +these online courses allow you to gain + + + align:start position:0% +these online courses allow you to gain +access to some of the world's leading + + align:start position:0% +access to some of the world's leading + + + align:start position:0% +access to some of the world's leading +experts in your particular field the + + align:start position:0% +experts in your particular field the + + + align:start position:0% +experts in your particular field the +role of the corporation in the US has + + align:start position:0% +role of the corporation in the US has + + + align:start position:0% +role of the corporation in the US has +changed quite a bit so it's time to + + align:start position:0% +changed quite a bit so it's time to + + + align:start position:0% +changed quite a bit so it's time to +really bring all of this together and + + align:start position:0% +really bring all of this together and + + + align:start position:0% +really bring all of this together and +see if we can't help really shape the + + align:start position:0% +see if we can't help really shape the + + + align:start position:0% +see if we can't help really shape the +future of work we're going to introduce + + align:start position:0% +future of work we're going to introduce + + + align:start position:0% +future of work we're going to introduce +rce you to lots of companies that are + + align:start position:0% +rce you to lots of companies that are + + + align:start position:0% +rce you to lots of companies that are +breaking new ground in every industry we + + align:start position:0% +breaking new ground in every industry we + + + align:start position:0% +breaking new ground in every industry we +can find great companies that are doing + + align:start position:0% +can find great companies that are doing + + + align:start position:0% +can find great companies that are doing +well financially serving their customers + + align:start position:0% +well financially serving their customers + + + align:start position:0% +well financially serving their customers +well focused on a mission that is really + + align:start position:0% +well focused on a mission that is really + + + align:start position:0% +well focused on a mission that is really +important for society and providing good + + align:start position:0% +important for society and providing good + + + align:start position:0% +important for society and providing good +jobs one of the things we want to do is + + align:start position:0% +jobs one of the things we want to do is + + + align:start position:0% +jobs one of the things we want to do is +to highlight those and to learn more + + align:start position:0% +to highlight those and to learn more + + + align:start position:0% +to highlight those and to learn more +about your own experiences with + + align:start position:0% +about your own experiences with + + + align:start position:0% +about your own experiences with +companies and organizations like this + + align:start position:0% +companies and organizations like this + + + align:start position:0% +companies and organizations like this +and so as we go along we're going to + + align:start position:0% +and so as we go along we're going to + + + align:start position:0% +and so as we go along we're going to +learn from your experiences and you're + + align:start position:0% +learn from your experiences and you're + + + align:start position:0% +learn from your experiences and you're +going to meet a whole set of peers who + + align:start position:0% +going to meet a whole set of peers who + + + align:start position:0% +going to meet a whole set of peers who +have good jobs and maybe not such good + + align:start position:0% +have good jobs and maybe not such good + + + align:start position:0% +have good jobs and maybe not such good +jobs some mentors who are ready to work + + align:start position:0% +jobs some mentors who are ready to work + + + align:start position:0% +jobs some mentors who are ready to work +with you to provide advice and all of + + align:start position:0% +with you to provide advice and all of + + + align:start position:0% +with you to provide advice and all of +that will be a learning process together + + align:start position:0% +that will be a learning process together + + + align:start position:0% +that will be a learning process together +and let me say a word about another + + align:start position:0% +and let me say a word about another + + + align:start position:0% +and let me say a word about another +piece of this course that I'm especially + + align:start position:0% +piece of this course that I'm especially + + + align:start position:0% +piece of this course that I'm especially +excited about in every week we're going + + align:start position:0% +excited about in every week we're going + + + align:start position:0% +excited about in every week we're going +to have something called the personal + + align:start position:0% +to have something called the personal + + + align:start position:0% +to have something called the personal +development Corner this is designed to + + align:start position:0% +development Corner this is designed to + + + align:start position:0% +development Corner this is designed to +provide you with a path forward so that + + align:start position:0% +provide you with a path forward so that + + + align:start position:0% +provide you with a path forward so that +you can be empowered to take control of + + align:start position:0% +you can be empowered to take control of + + + align:start position:0% +you can be empowered to take control of +your own career so they'll be readings + + align:start position:0% +your own career so they'll be readings + + + align:start position:0% +your own career so they'll be readings +and videos and exercises and assignments + + align:start position:0% +and videos and exercises and assignments + + + align:start position:0% +and videos and exercises and assignments +that allow you to understand what are + + align:start position:0% +that allow you to understand what are + + + align:start position:0% +that allow you to understand what are +some of your capabilities what are some + + align:start position:0% +some of your capabilities what are some + + + align:start position:0% +some of your capabilities what are some +of your interests what jobs might fit + + align:start position:0% +of your interests what jobs might fit + + + align:start position:0% +of your interests what jobs might fit +well with your background and where you + + align:start position:0% +well with your background and where you + + + align:start position:0% +well with your background and where you +would like to go with your own career + + align:start position:0% +would like to go with your own career + + + align:start position:0% +would like to go with your own career +and how will you develop your own + + align:start position:0% +and how will you develop your own + + + align:start position:0% +and how will you develop your own +personal career plan to make sure that + + align:start position:0% +personal career plan to make sure that + + + align:start position:0% +personal career plan to make sure that +you are ready to take advantage of the + + align:start position:0% +you are ready to take advantage of the + + + align:start position:0% +you are ready to take advantage of the +opportunities that are out + + align:start position:0% +opportunities that are out + + + align:start position:0% +opportunities that are out +there so let's start exploring this + + align:start position:0% +there so let's start exploring this + + + align:start position:0% +there so let's start exploring this +evolving and interesting world of work + + align:start position:0% +evolving and interesting world of work + + + align:start position:0% +evolving and interesting world of work +let's do it with our eyes open let's + + align:start position:0% +let's do it with our eyes open let's + + + align:start position:0% +let's do it with our eyes open let's +understand and learn from our history + + align:start position:0% +understand and learn from our history + + + align:start position:0% +understand and learn from our history +about what worked in the past what's + + align:start position:0% +about what worked in the past what's + + + align:start position:0% +about what worked in the past what's +broken what needs to be fixed and why + + align:start position:0% +broken what needs to be fixed and why + + + align:start position:0% +broken what needs to be fixed and why +and then let's see if together we can't + + align:start position:0% +and then let's see if together we can't + + + align:start position:0% +and then let's see if together we can't +shape the future of work for your + + align:start position:0% +shape the future of work for your + + + align:start position:0% +shape the future of work for your +generation so let's get + + align:start position:0% + + + + align:start position:0% + +started for \ No newline at end of file diff --git a/dLeI7A7VezQ.txt b/dLeI7A7VezQ.txt new file mode 100644 index 0000000000000000000000000000000000000000..5ef1c95800b9c2d6b29fdaced9d778907729d711 --- /dev/null +++ b/dLeI7A7VezQ.txt @@ -0,0 +1,207 @@ +Suppose we have a real-time system supporting +three devices: + +a keyboard whose interrupt handler has a service +time of 800 us, + +a disk with a service time of 500 us, +and a printer with a service time of 400 us. + +What is the worst-case latency seen by each +device? + +For now we'll assume that requests are infrequent, +i.e., that each request only happens once + +in each scenario. + +Requests can arrive at any time and in any +order. + +If we serve the requests in first-come-first-served +order, each device might be delayed by the + +service of all other devices. + +So the start of the keyboard handler might +be delayed by the execution of the disk and + +printer handlers, a worst-case latency of +900 us. + +The start of the disk handler might be delayed +by the keyboard and printer handlers, a worst-case + +latency of 1200 us. + +And the printer handler might be delayed by +the keyboard and disk handlers, a worst-case + +latency of 1300 us. + +In this scenario we see that long-running +handlers have a huge impact on the worst-case + +latency seen by the other devices. + +What are the possibilities for reducing the +worst-case latencies? + +Is there a better scheduling algorithm than +first-come-first-served? + +One strategy is to assign priorities to the +pending requests and to serve the requests + +in priority order. + +If the handlers are uninterruptible, the priorities +will be used to select the *next* task to + +be run at the completion of the current task. + +Note that under this strategy, the current +task always runs to completion even if a higher-priority + +request arrives while it's executing. + +This is called a "nonpreemptive" or "weak" +priority system. + +Using a weak priority system, the worst-case +latency seen by each device is the worst-case + +service time of all the other devices +(since that handler may have just started + +running when the new request arrives), +plus the service time of all higher-priority + +devices (since they'll be run first). + +In our example, suppose we assigned the highest +priority to the disk, the next priority to + +the printer, and the lowest priority to the +keyboard. + +The worst-case latency of the keyboard is +unchanged since it has the lowest priority + +and hence can be delayed by the higher-priority +disk and printer handlers. + +The disk handler has the highest priority +and so will always be selected for execution + +after the current handler completes. + +So its worst-case latency is the worst-case +service time for the currently-running handler, + +which in this case is the keyboard. + +So the worst-case latency for the disk is +800 us. + +This is a considerable improvement over the +first-come-first-served scenario. + +Finally the worst-case scenario for the printer +is 1300 us since it may have to wait for the + +keyboard handler to finish (which can take +up to 800 us) + +and then for a higher-priority disk request +to be serviced (which takes 500 us). + +How should priorities be assigned given hard +real-time constraints? + +We'll assume each device has a service deadline +D after the arrival of its service request. + +If not otherwise specified, assume D is the +time until the *next* request for the same + +device. + +This is a reasonably conservative assumption +that prevents the system from falling further + +and further behind. + +For example, it makes sense that the keyboard +handler should finish processing one character + +before the next arrives. + +"Earliest Deadline" is a strategy for assigning +priorities that is guaranteed to meet the + +deadlines if any priority assignment can meet +the deadlines. + +It's very simple: Sort the requests by their +deadlines. + +Assign the highest priority to the earliest +deadline, second priority to the next deadline, + +and so on. + +A weak priority system will choose the pending +request with the highest priority, i.e., the + +request that has the earliest deadline. + +Earliest Deadline has an intuitive appeal. + +Imagine standing in a long security line at +the airport. + +It would make sense to prioritize the processing +of passengers who have the earliest flights + +assuming that there's enough time to process +everyone before their flight leaves. + +Processing 10 people whose flights leave in +30 minutes before someone whose flight leaves + +in 5 min will cause that last person to miss +their flight. + +But if that person is processed first, the +other passengers may be slightly delayed but + +everyone will make their flight. + +This is the sort of scheduling problem that +Earliest Deadline and a weak priority system + +can solve. + +It's outside the scope of our discussion, +but it's interesting to think about what should + +happen if some flights are going to be missed. + +If the system is overloaded, prioritizing +by earliest deadline may mean that everyone + +will miss their flights! + +In this scenario it might be better to assign +priorities to the minimize the total number + +of missed flights. + +This gets complicated in a hurry since the +assignment of priorities now depends on exactly + +what requests are pending and how long it +will take them to be serviced. + +An intriguing problem to think about! \ No newline at end of file diff --git a/dbSKZx9sfsg.txt b/dbSKZx9sfsg.txt new file mode 100644 index 0000000000000000000000000000000000000000..237b76f2a2993d82ff7e969aaf8962ec2f47f7ed --- /dev/null +++ b/dbSKZx9sfsg.txt @@ -0,0 +1,924 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high-quality educational +resources for free. + +To make a donation, or view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu. + +Hi. + +I'm Jocelyn, and we're going to +go over fall 2009, exam 1, + +problem number 3. + +With every question, we want to +make sure we read the full + +problem first. So answer the +following questions about the + +difluoro-iodate ion. + +Draw a three-dimensional +representation of the + +molecular geometry around the +central atom, not simply the + +Lewis structure. + +Show all atoms and bonds +between them. + +Because this part seems pretty +separate from the rest of + +them, we're going to +start with that. + +So we have a difluoro-iodate +ion. + +It has a positive charge. + +And it asks us to draw the +molecular geometry in a 3D + +representation, and not +just Lewis structure. + +However, to do the molecular +geometry in 3D, we need to + +know the Lewis structure. + +So we're going to +start with that. + +To draw the Lewis structure, +we first need to figure out + +which atom is the +central atom. + +And it's always a good idea to +do that by looking at the + +relative electronegativities. + +As we know, fluorine is the most +electronegative element + +in the periodic table, and so +that's probably not going to + +be in the middle. + +Therefore, iodine, being the +less electronegative, is going + +to be in the middle, +and it will have + +fluorines on either side. + +This is our rough sketch of +the molecular geometry. + +Not too important right now. + +Next we need to know how many +electrons we have. Iodine has + +seven valence electrons, +fluoride has seven valence + +electrons, and we have a +positive charge, so we know + +that we're missing one. + +And that gives us +20 electrons. + +Now that we know how many +electrons we have to work + +with, we need start +filling them in. + +I always start with the +outer electrons. + +Those are usually, hopefully, +the most electronegative, and + +therefore, the most likely to +have the octet rule satisfied. + +Also, if you remember, fluorine +is in the second row, + +and therefore needs to have +the octet rule satisfied. + +Iodine is a little bit lower in +the periodic table, so the + +octet rule isn't as important. + +It can have an extended octet +if we need it to. + +So we will work with +iodine second. + +Let's start out with satisfying +the octet rule for + +the fluorine, putting first the +seven valence electrons + +that the fluorines brought +themselves, and then noticing + +that each needs to share one +from iodine, so that we have a + +full octet. + +So each has one bond +with iodine. + +We've used 8 electrons, +or 8 per fluorine. + +So we have a total of 16. + +We have 4 left, and +we're going to put + +those on the iodine. + +Counting up how many electronics +are around iodine, + +1, 2, 3, 4, 5, 6, 7, 8, we see +that the octet rule is also + +satisfied for iodine. + +This is looking like a pretty +good Lewis structure. + +Now, just to make sure it's +really good, we're going to + +look at the formal charge. + +So if you recall, the formal +charge is the number of + +valence electrons that the +element usually has, and minus + +the number of unshared +electrons, and + +the number of dots. + +So this sum subtracted from +the valence electrons will + +give us the formal charge. + +Looking at the fluorine, we have +seven valence electrons. + +We have 1, 2, 3, 4, +5, 6 unpaired, and + +one bond to the fluorine. + +So that gives us a formal +charge of 0. + +The same goes for the +other fluorine. + +So I guess its formal +charge is 0. + +Now for the iodine, we have-- + +I'm going to do the formal +charge down here-- + +it again has 7 valence +electrons, usually. + +We have 4 unshared electrons, +and 2 bonds. + +That gives us a formal +charge of plus 1. + +Because we have a charged +species here, the full + +molecule has a plus 1 charge. + +There's no way we cannot have +a net formal charge. + +Right? + +We need to have a net formal +charge of plus 1. + +And it makes sense that that +formal charge is on the least + +electronegative atom. + +So this looks like +the right Lewis + +structure for our purposes. + +One more thing that you might +want to write down. + +I'm not sure if points were +taken off from this. + +But technically, if you have a +charged species, put brackets + +around your Lewis structure, +and put the net + +charge on the outside. + +This is not, however, our +final answer, right? + +This is the Lewis structure. + +But the question asks for the +molecular geometry to be + +represented. + +So if we remember how we +determine molecular geometry, + +we need to look at the number of +electron domains around the + +essential atom. + +So we're going to move over +here, and I'll redraw our + +Lewis structure. + +And remember, an electron +domain can be either an + +electron pair, or a bond. + +So we see that iodine has +4 electron domains. + +And if we remember our skeletal +geometry, we know + +that that's tetrahedral. + +Thus, to draw this in a more 3D +fashion, we might want to + +say that one of the electron +pairs is here, one of the + +electron pairs is over here, +and then we have a fluorine + +coming out of the board, and a +fluorine going into the board. + +We didn't really go +over how to do + +three-dimensional drawings. + +So as long as you show something +like, you know the + +fluorines will be an angle, not +straight from the iodine, + +and that the electrons be on the +other side, something to + +that effect. + +A little bit more detailed than +just a Lewis structure, + +was what Professor Sadoway was +looking for in this problem. + +And that would be your answer. + +And for this one especially, I'd +say it's important to box + +your final answer. + +Because you hopefully would +have figured out the Lewis + +structure, but this is not +the correct answer. + +So you always want to +signify what answer + +you want to be graded. + +Part B says, name the type of +hybrid orbitals that the + +central atom forms. So we are +almost all the way to + +answering this question, so +I'll put it down here. + +Remember, hybrid +orbitals are-- + +we have hybrid orbitals, because +we can't really say + +what orbitals exactly are +bonding to which atoms. We + +want to have 4 equivalent +orbitals for + +this system, right? + +We have 4 electron domains, +so we want 4 + +equivalent bonding orbitals. + +And from our talks earlier +in the lectures about + +hybridization, we know that if +we want 4, we take 1S and 3P, + +and that gives us the +hybridization of the SP3. + +if we only had 3 electron +domains, it would be SP2, + +because we only use +3 orbitals. + +And the number of orbitals that +go into the hybrid is the + +number of orbitals +you will get out. + +So we know that our +hybridization is SP3. + +And that goes along with the +fact that our shape is + +tetrahedral. + +Now we need to name +the molecular + +geometry of this molecule. + +so we already have the molecular +shape and the kind + +of spacial arrangement +is tetrahedral. + +However, when we're naming the +molecular geometry, electron + +pairs no longer matter. + +So for part C, tetrahedral is +our skeletal geometry, right? + +It shows us our special +arrangement. + +The molecular geometry is +ignoring those electron pairs. + +So it is called bent when +we only have 2 bonds. + +And I think about that because +in spectroscopy and ways that + +are used to study molecules, +you can't see the electron + +clouds very well. + +So they could only see the +iodine and the two fluorines, + +thus looking like a +bent structure. + +So hopefully you're sticking +with me here, because this + +problem has a lot of parts. + +And we're going to move +on to part D now. + +Part D asks, is difluoro-iodate +polar or + +nonpolar, and explain. + +If you put down polar or +nonpolar and did not explain, + +we assume you guessed, and you +didn't get any points. + +Explaining shows that you know +why, and you understand the + +concepts behind this, +and thus deserved + +points on this problem. + +So there's two different +parts of this problem. + +First, to have a polar molecule, +you need to have + +polar bonds. + +So I would first ask myself, +are the bonds polar? + +We have a difference of +electronegativity that you can + +look up on your periodic table +and know is not negligible. + +And so yes. + +A difference in +electronegativity signifies + +that our bonds are polar. + +However, not all molecules +that have polar bonds are + +themselves polar, right? + +if we have spacial symmetry, +those polar bonds + +could cancel out. + +So now we need to make sure, +is the molecule polar? + +And for that, we need +to have answered the + +first questions correctly. + +Right? + +We need to know that this is +not a linear structure. + +If this was a linear structure, +those polar bonds + +would be geometrically +symmetric, and + +cancel each other out. + +But we all are very smart, and +we got this part C right. + +We know that we have +a bent structure. + +Thus, I'll rewrite +this over here. + +We know that if we draw in our +polarity vectors, we can + +realize that we'll have a net +dipole pointing down. + +So the answer to this is yes, +because of the difference in + +the electronegativity, +and because + +of the spacial asymmetry. + +If you said both of +those things, you + +would get full credit. + +If you said one or +the other, you'd + +probably get part credit. + +But knowing to look at these +two things shows that you + +fully understand what it means +to have molecular polarity. + +All right. + +So now we're going to +move to part E. + +This part is changing gears a +little bit, so if you didn't + +quite understand the +first part, you can + +still try this one. + +Part E, again, what is the +question asking us? + +Determine the maximum wavelength +of electromagnetic + +radiation capable of breaking +the IS bond. + +So we need to find the maximum +wavelengths which corresponds + +to the minimum energy. + +Right? + +Because we have e equals +hc over over lambda for + +electromagnetic radiation. + +We're trying to figure out the +lowest energy of photon that + +will break the IF bond. + +Now, what are we given to +answer this question? + +We're given the energy of the +homogeneous fluorine-fluorine + +bond, is 160 kilojoules +per mole. + +And the energy of the +homogeneous iodine-iodine bond + +is 150 kilojoules per mole. + +And in order to find the +wavelength that will break the + +IS bond, we need to know the +energy of the IS bond. + +Right? + +That's what we're working +towards in this problem. + +So given the homogeneous +energies, do we have a + +relationship that will +help us determine the + +energy of the IS bond? + +If you recall, in lecture 9, +Professor Sadoway went over + +the Pauling formula for +determining a heterogeneous + +bond energy from the homogeneous +bond energies, and + +the electronegativity. + +So I'll just write +that up here. + +The Pauling formula is, in a +generic form, the energy of an + +AB bond equals the square root +of the product of the + +homogeneous bond energies plus +a constant times the + +difference between the +electronegativities squared. + +And I just said what all +of these terms mean. + +Because even if you had this on +your equation sheet in the + +test or something, a lot of +people wrote this down, and + +then used it incorrectly. + +So it's really important to know +not only what equations + +you have, but especially what +each of the terms in the + +equations mean. + +So we're given the homogeneous +bond energies, and we have a + +periodic table, or some other +resource, that has the + +elecronegativities. + +Next step is to plug in the +numbers and find the energy of + +the IF bond. + +So we have the square root +of 150 kilojoules plus. + +And the exact values you get for +the electronegativity may + +vary, depending on the source. + +But they'll be close +enough, and + +relatively, probably very-- + +the difference between them +will be very similar. + +So don't worry if your +numbers were a little + +different than mine. + +So we wrote all that out, +and plugging it into the + +calculator, you get that the IF +bond has an energy of 323 + +kilojoules per mole. + +Now that we've found the energy +of the IS bond, are we + +done with the problem? + +You have an answer. + +You might be ready to move +on to the next question. + +However, this isn't what the +question is asking us, right? + +We are asked for the maximum +wavelength that can break a + +bond of that energy. + +So we need to go back to our +energy relation to our + +wavelengths. + +And we know that the wavelength + +equals hc over the energy. + +Now here's where some people +tripped up a little bit. + +You have a value +for the energy. + +h and c are constants. + +And you find the lambda. + +However, if you plugged that all +in, your answer would be + +6.15 times 10 to the +negative 31 meters. + +Some people, that was the +answer that they found. + +And it makes sense. + +You have an energy, you have +some constants, and you can + +get your lambda. + +However, if you think about +it, does this wavelength + +actually make sense? + +The gamma ray radiation has a +wavelength of about 10 to the + +negative 17. + +That's very, very, +very energetic + +electromagnetic radiation. + +So this is 14 magnitudes +smaller than gamma ray + +radiation, and it just doesn't +make sense for a bond energy + +of this much. + +Plus it doesn't-- + +it just-- you should look at the +answer you get, and try to + +be comfortable with if it +makes sense or not. + +So where people got tripped +up, is in the units. + +We found Pauling's formula gives +you the bond energy in + +kilojoules per mole. + +However, if you look at Planck's +constant, it has + +units of joules time seconds. + +The speed of light is in +meters per second. + +And you want lambda in meters. + +To make everything or cancel +out, that means we want the + +energy to be in joules. + +Not joules per mole, because +we're looking at the + +wavelength of one +photon, right? + +We're looking at the energy of +one photon to break this bond. + +So we want the energy of the +bond, not per mole of bonds, + +but just of one bond. + +So instead of just having this +equation, we want to have put + +in h times c over 323, change +it to joules, and then + +multiply by-- + +sorry, moles are on +the bottom, 1 mole + +and Avogadro's number. + +And Planck's constant of the +speed of light, you should + +have on your equation sheet, or +somewhere else, some other + +resource that you have. You +don't need to memorize those + +in most cases. + +If you remembered to divide by +Avogadro's number, you got 3.7 + +times 10 to the negative 7 +meters, which equals 370 + +nanometers. + +And if we recall, the light we +can see is in the 400 to 700 + +nanometer range. + +So this puts us in ultraviolet +radiation, which makes sense + +that it would take that much +energy to break a bond. + +The other problem some people +had was forgetting to convert + +from kilojoules to joules. + +That would still give you +a physical answer. + +But again, I can't stress +unit cancel out enough. + +So make sure you know that since +your Planck's constant + +is in joules, you want +to make sure you have + +joules on the bottom. \ No newline at end of file diff --git a/f1pxiNDTyHc.txt b/f1pxiNDTyHc.txt new file mode 100644 index 0000000000000000000000000000000000000000..32028043aec6573eb5dec66343cc29af0cf68590 --- /dev/null +++ b/f1pxiNDTyHc.txt @@ -0,0 +1,9403 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT OpenCourseWare continue to + + align:start position:0% +will help MIT OpenCourseWare continue to + + + align:start position:0% +will help MIT OpenCourseWare continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or to view additional + + align:start position:0% +to make a donation or to view additional + + + align:start position:0% +to make a donation or to view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +today we're going to talk about + + align:start position:0% +today we're going to talk about + + + align:start position:0% +today we're going to talk about +vibrations topic of vibration isolation + + align:start position:0% +vibrations topic of vibration isolation + + + align:start position:0% +vibrations topic of vibration isolation +which is a very practical use of knowing + + align:start position:0% +which is a very practical use of knowing + + + align:start position:0% +which is a very practical use of knowing +a little bit about vibration so imagine + + align:start position:0% +a little bit about vibration so imagine + + + align:start position:0% +a little bit about vibration so imagine +you've probably been in a situation + + align:start position:0% +you've probably been in a situation + + + align:start position:0% +you've probably been in a situation +you've been in where there's an air + + align:start position:0% +you've been in where there's an air + + + align:start position:0% +you've been in where there's an air +conditioner in a window and it's causing + + align:start position:0% +conditioner in a window and it's causing + + + align:start position:0% +conditioner in a window and it's causing +your table to shake or where you're + + align:start position:0% +your table to shake or where you're + + + align:start position:0% +your table to shake or where you're +trying to work or your bed rattles or + + align:start position:0% +trying to work or your bed rattles or + + + align:start position:0% +trying to work or your bed rattles or +something like that how many of you have + + align:start position:0% +something like that how many of you have + + + align:start position:0% +something like that how many of you have +ever had an experience like that + + align:start position:0% +ever had an experience like that + + + align:start position:0% +ever had an experience like that +something's kind of annoying messing up + + align:start position:0% +something's kind of annoying messing up + + + align:start position:0% +something's kind of annoying messing up +a lab experiment or whatever yeah you've + + align:start position:0% +a lab experiment or whatever yeah you've + + + align:start position:0% +a lab experiment or whatever yeah you've +all experienced these things right so + + align:start position:0% +all experienced these things right so + + + align:start position:0% +all experienced these things right so +what can you know can we as as clever + + align:start position:0% +what can you know can we as as clever + + + align:start position:0% +what can you know can we as as clever +engineers are there simple solutions + + align:start position:0% +engineers are there simple solutions + + + align:start position:0% +engineers are there simple solutions +sometimes to fixing these problems and + + align:start position:0% +sometimes to fixing these problems and + + + align:start position:0% +sometimes to fixing these problems and +that's what we're going to that's we're + + align:start position:0% +that's what we're going to that's we're + + + align:start position:0% +that's what we're going to that's we're +going to talk about today I have a + + align:start position:0% +going to talk about today I have a + + + align:start position:0% +going to talk about today I have a +little quick demo that I'm going to show + + align:start position:0% +little quick demo that I'm going to show + + + align:start position:0% +little quick demo that I'm going to show +you you saw this the other the other day + + align:start position:0% +you you saw this the other the other day + + + align:start position:0% +you you saw this the other the other day +or this is my little squiggle pen and + + align:start position:0% +or this is my little squiggle pen and + + + align:start position:0% +or this is my little squiggle pen and +it's got a rotating mass inside and + + align:start position:0% +it's got a rotating mass inside and + + + align:start position:0% +it's got a rotating mass inside and +we've looked at rotating masses a lot so + + align:start position:0% +we've looked at rotating masses a lot so + + + align:start position:0% +we've looked at rotating masses a lot so +it has some unbalanced statically + + align:start position:0% +it has some unbalanced statically + + + align:start position:0% +it has some unbalanced statically +unbalanced rotating mass could be a fan + + align:start position:0% +unbalanced rotating mass could be a fan + + + align:start position:0% +unbalanced rotating mass could be a fan +blade with a hunk of chewing gum or + + align:start position:0% +blade with a hunk of chewing gum or + + + align:start position:0% +blade with a hunk of chewing gum or +something stuck on a blade or broken + + align:start position:0% +something stuck on a blade or broken + + + align:start position:0% +something stuck on a blade or broken +piece out of it puts in a four semi + + align:start position:0% +piece out of it puts in a four semi + + + align:start position:0% +piece out of it puts in a four semi +Omega squared cosine Omega T basically + + align:start position:0% +Omega squared cosine Omega T basically + + + align:start position:0% +Omega squared cosine Omega T basically +an F naught cosine Omega T kind of + + align:start position:0% +an F naught cosine Omega T kind of + + + align:start position:0% +an F naught cosine Omega T kind of +excitation and if it happens to be a + + align:start position:0% +excitation and if it happens to be a + + + align:start position:0% +excitation and if it happens to be a +flexibly mounted mass spring dashpot + + align:start position:0% +flexibly mounted mass spring dashpot + + + align:start position:0% +flexibly mounted mass spring dashpot +system it'll vibrate so I showed you + + align:start position:0% +system it'll vibrate so I showed you + + + align:start position:0% +system it'll vibrate so I showed you +that the other day we'll do this and + + align:start position:0% +that the other day we'll do this and + + + align:start position:0% +that the other day we'll do this and +we'll need to lower the lights a little + + align:start position:0% + + + + align:start position:0% + +but today I have set your bed here this + + align:start position:0% +but today I have set your bed here this + + + align:start position:0% +but today I have set your bed here this +is your microscope here a little one you + + align:start position:0% +is your microscope here a little one you + + + align:start position:0% +is your microscope here a little one you +can see it in foreground and this is + + align:start position:0% +can see it in foreground and this is + + + align:start position:0% +can see it in foreground and this is +your air conditioner or the water pump + + align:start position:0% +your air conditioner or the water pump + + + align:start position:0% +your air conditioner or the water pump +or whatever it's causing the trouble so + + align:start position:0% +or whatever it's causing the trouble so + + + align:start position:0% +or whatever it's causing the trouble so +this is running about 28 Hertz is what + + align:start position:0% +this is running about 28 Hertz is what + + + align:start position:0% +this is running about 28 Hertz is what +if I set this strobe just right I can + + align:start position:0% +if I set this strobe just right I can + + + align:start position:0% +if I set this strobe just right I can +absolutely stop the motion it doesn't + + align:start position:0% +absolutely stop the motion it doesn't + + + align:start position:0% +absolutely stop the motion it doesn't +look like it's moving at all that's + + align:start position:0% +look like it's moving at all that's + + + align:start position:0% +look like it's moving at all that's +because the strobe is at exactly the + + align:start position:0% +because the strobe is at exactly the + + + align:start position:0% +because the strobe is at exactly the +same rate as the squiggle pen now I'm + + align:start position:0% +same rate as the squiggle pen now I'm + + + align:start position:0% +same rate as the squiggle pen now I'm +going to detune the strobe a little bit + + align:start position:0% +going to detune the strobe a little bit + + + align:start position:0% +going to detune the strobe a little bit +so you can see the motion there's the + + align:start position:0% +so you can see the motion there's the + + + align:start position:0% +so you can see the motion there's the +motion of this main system that's the + + align:start position:0% +motion of this main system that's the + + + align:start position:0% +motion of this main system that's the +process causing the problem but it + + align:start position:0% +process causing the problem but it + + + align:start position:0% +process causing the problem but it +actually puts the vibration into the + + align:start position:0% +actually puts the vibration into the + + + align:start position:0% +actually puts the vibration into the +tabletop a next door over here I have a + + align:start position:0% +tabletop a next door over here I have a + + + align:start position:0% +tabletop a next door over here I have a +little beam and you can just see that + + align:start position:0% +little beam and you can just see that + + + align:start position:0% +little beam and you can just see that +little piece of white moving up and down + + align:start position:0% +little piece of white moving up and down + + + align:start position:0% +little piece of white moving up and down +it's just a little flat piece of spring + + align:start position:0% +it's just a little flat piece of spring + + + align:start position:0% +it's just a little flat piece of spring +steel with a magnet on the end as a mass + + align:start position:0% +steel with a magnet on the end as a mass + + + align:start position:0% +steel with a magnet on the end as a mass +and a piece of white tape so you can see + + align:start position:0% +and a piece of white tape so you can see + + + align:start position:0% +and a piece of white tape so you can see +it but notice it's going up and down in + + align:start position:0% +it but notice it's going up and down in + + + align:start position:0% +it but notice it's going up and down in +synchrony with the other one so this is + + align:start position:0% +synchrony with the other one so this is + + + align:start position:0% +synchrony with the other one so this is +some this is your microscope sitting on + + align:start position:0% +some this is your microscope sitting on + + + align:start position:0% +some this is your microscope sitting on +a lab bench some distance away the + + align:start position:0% +a lab bench some distance away the + + + align:start position:0% +a lab bench some distance away the +problem vibrations being created by the + + align:start position:0% +problem vibrations being created by the + + + align:start position:0% +problem vibrations being created by the +original imbalance in something travels + + align:start position:0% +original imbalance in something travels + + + align:start position:0% +original imbalance in something travels +through the floor gets to your table + + align:start position:0% +through the floor gets to your table + + + align:start position:0% +through the floor gets to your table +with the microscope on it now your + + align:start position:0% +with the microscope on it now your + + + align:start position:0% +with the microscope on it now your +microscope shakes so what can we the + + align:start position:0% +microscope shakes so what can we the + + + align:start position:0% +microscope shakes so what can we the +issue is what can we do about it + + align:start position:0% + + + + align:start position:0% + +okay oh I do yeah and we'll leave this + + align:start position:0% +okay oh I do yeah and we'll leave this + + + align:start position:0% +okay oh I do yeah and we'll leave this +for a second I'll turn it off and then + + align:start position:0% +for a second I'll turn it off and then + + + align:start position:0% +for a second I'll turn it off and then +I'm going to have you consider so I want + + align:start position:0% +I'm going to have you consider so I want + + + align:start position:0% +I'm going to have you consider so I want +you to you know get in pairs and talk + + align:start position:0% +you to you know get in pairs and talk + + + align:start position:0% +you to you know get in pairs and talk +about this I want as a group we're going + + align:start position:0% +about this I want as a group we're going + + + align:start position:0% +about this I want as a group we're going +to come up with at least three ways to + + align:start position:0% +to come up with at least three ways to + + + align:start position:0% +to come up with at least three ways to +reduce the vibration of your microscope + + align:start position:0% +reduce the vibration of your microscope + + + align:start position:0% +reduce the vibration of your microscope +relatively simple ways to fix it how + + align:start position:0% +relatively simple ways to fix it how + + + align:start position:0% +relatively simple ways to fix it how +would you do it + + align:start position:0% +would you do it + + + align:start position:0% +would you do it +figure give me so think about it talk + + align:start position:0% +figure give me so think about it talk + + + align:start position:0% +figure give me so think about it talk +about it and come up with three ways of + + align:start position:0% +about it and come up with three ways of + + + align:start position:0% +about it and come up with three ways of +fixing this problem + + align:start position:0% + + + + align:start position:0% + +I'm going to do one more demo on this in + + align:start position:0% +I'm going to do one more demo on this in + + + align:start position:0% +I'm going to do one more demo on this in +a minute and then put up the transfer + + align:start position:0% +a minute and then put up the transfer + + + align:start position:0% +a minute and then put up the transfer +function for the force the one we had + + align:start position:0% +function for the force the one we had + + + align:start position:0% +function for the force the one we had +the other day okay a picture + + align:start position:0% + + + + align:start position:0% + +all right let's have some suggestions + + align:start position:0% +all right let's have some suggestions + + + align:start position:0% +all right let's have some suggestions +how would you go about fixing this + + align:start position:0% + + + + align:start position:0% + +all right so put it put some Springs on + + align:start position:0% +all right so put it put some Springs on + + + align:start position:0% +all right so put it put some Springs on +what the spring support the microscope + + align:start position:0% +what the spring support the microscope + + + align:start position:0% +what the spring support the microscope +all right so I have this blue this + + align:start position:0% +all right so I have this blue this + + + align:start position:0% +all right so I have this blue this +little magnet here sitting on this beam + + align:start position:0% +little magnet here sitting on this beam + + + align:start position:0% +little magnet here sitting on this beam +this is that spring supported microscope + + align:start position:0% +this is that spring supported microscope + + + align:start position:0% +this is that spring supported microscope +but I've done a heck of a lousy job this + + align:start position:0% +but I've done a heck of a lousy job this + + + align:start position:0% +but I've done a heck of a lousy job this +thing shakes like crazy so what do you + + align:start position:0% +thing shakes like crazy so what do you + + + align:start position:0% +thing shakes like crazy so what do you +mean not like that how am i okay so if + + align:start position:0% +mean not like that how am i okay so if + + + align:start position:0% +mean not like that how am i okay so if +you think that you could change the + + align:start position:0% +you think that you could change the + + + align:start position:0% +you think that you could change the +properties of this system so that it + + align:start position:0% +properties of this system so that it + + + align:start position:0% +properties of this system so that it +might do better let's think about that + + align:start position:0% +might do better let's think about that + + + align:start position:0% +might do better let's think about that +okay what's another idea + + align:start position:0% + + + + align:start position:0% + +yeah if you change the length are you + + align:start position:0% +yeah if you change the length are you + + + align:start position:0% +yeah if you change the length are you +talking about the microscope one the + + align:start position:0% +talking about the microscope one the + + + align:start position:0% +talking about the microscope one the +receiving one if you change the length + + align:start position:0% +receiving one if you change the length + + + align:start position:0% +receiving one if you change the length +of it it change it make it longer it + + align:start position:0% +of it it change it make it longer it + + + align:start position:0% +of it it change it make it longer it +makes it softer actually make it shorter + + align:start position:0% +makes it softer actually make it shorter + + + align:start position:0% +makes it softer actually make it shorter +it makes it stiffer so you would change + + align:start position:0% +it makes it stiffer so you would change + + + align:start position:0% +it makes it stiffer so you would change +its natural frequency that's that now + + align:start position:0% +its natural frequency that's that now + + + align:start position:0% +its natural frequency that's that now +the two ideas together you if you set + + align:start position:0% +the two ideas together you if you set + + + align:start position:0% +the two ideas together you if you set +the natural frequency correctly you can + + align:start position:0% +the natural frequency correctly you can + + + align:start position:0% +the natural frequency correctly you can +actually make that says the second the + + align:start position:0% +actually make that says the second the + + + align:start position:0% +actually make that says the second the +system on the receiving end you can + + align:start position:0% +system on the receiving end you can + + + align:start position:0% +system on the receiving end you can +reduce its vibration and I will + + align:start position:0% +reduce its vibration and I will + + + align:start position:0% +reduce its vibration and I will +demonstrate that in a second what's + + align:start position:0% +demonstrate that in a second what's + + + align:start position:0% +demonstrate that in a second what's +another idea after damping okay well + + align:start position:0% +another idea after damping okay well + + + align:start position:0% +another idea after damping okay well +that's a very interesting suggestion + + align:start position:0% +that's a very interesting suggestion + + + align:start position:0% +that's a very interesting suggestion +damping it helped under one circumstance + + align:start position:0% +damping it helped under one circumstance + + + align:start position:0% +damping it helped under one circumstance +but not under some others we're going to + + align:start position:0% +but not under some others we're going to + + + align:start position:0% +but not under some others we're going to +explore that today what so but we + + align:start position:0% +explore that today what so but we + + + align:start position:0% +explore that today what so but we +Stella's is all basically we've come up + + align:start position:0% +Stella's is all basically we've come up + + + align:start position:0% +Stella's is all basically we've come up +with one of the three ideas what else oh + + align:start position:0% + + + + align:start position:0% + +that's interesting that's the fourth one + + align:start position:0% +that's interesting that's the fourth one + + + align:start position:0% +that's interesting that's the fourth one +I mean that that can be a little + + align:start position:0% +I mean that that can be a little + + + align:start position:0% +I mean that that can be a little +expensive but these are like noise + + align:start position:0% +expensive but these are like noise + + + align:start position:0% +expensive but these are like noise +cancelling mic headsets right could we + + align:start position:0% +cancelling mic headsets right could we + + + align:start position:0% +cancelling mic headsets right could we +put in something else somewhere else on + + align:start position:0% +put in something else somewhere else on + + + align:start position:0% +put in something else somewhere else on +the table that cancels the vibration at + + align:start position:0% +the table that cancels the vibration at + + + align:start position:0% +the table that cancels the vibration at +where you're trying to wear your + + align:start position:0% +where you're trying to wear your + + + align:start position:0% +where you're trying to wear your +microscope is yeah you could do that a + + align:start position:0% +microscope is yeah you could do that a + + + align:start position:0% +microscope is yeah you could do that a +little expensive what else yeah where + + align:start position:0% +little expensive what else yeah where + + + align:start position:0% +little expensive what else yeah where +would you put that yeah and so that's + + align:start position:0% +would you put that yeah and so that's + + + align:start position:0% +would you put that yeah and so that's +generally the same idea so you're all + + align:start position:0% +generally the same idea so you're all + + + align:start position:0% +generally the same idea so you're all +treating the microscope it can you treat + + align:start position:0% +treating the microscope it can you treat + + + align:start position:0% +treating the microscope it can you treat +something else in the system so yeah + + align:start position:0% +something else in the system so yeah + + + align:start position:0% +something else in the system so yeah +we'll fix the microscope end but that + + align:start position:0% +we'll fix the microscope end but that + + + align:start position:0% +we'll fix the microscope end but that +might knock it down by a factor of 10 I + + align:start position:0% +might knock it down by a factor of 10 I + + + align:start position:0% +might knock it down by a factor of 10 I +want to knock it bound by at least a + + align:start position:0% +want to knock it bound by at least a + + + align:start position:0% +want to knock it bound by at least a +factor of 100 if not a factor of a + + align:start position:0% +factor of 100 if not a factor of a + + + align:start position:0% +factor of 100 if not a factor of a +thousand ah you know put another piece + + align:start position:0% +thousand ah you know put another piece + + + align:start position:0% +thousand ah you know put another piece +of gum on the other blade or tail or + + align:start position:0% +of gum on the other blade or tail or + + + align:start position:0% +of gum on the other blade or tail or +clean it up or balance the rotor in + + align:start position:0% +clean it up or balance the rotor in + + + align:start position:0% +clean it up or balance the rotor in +effect rotors are not manufactured + + align:start position:0% +effect rotors are not manufactured + + + align:start position:0% +effect rotors are not manufactured +defective usually they get rejected at + + align:start position:0% +defective usually they get rejected at + + + align:start position:0% +defective usually they get rejected at +the under at the quote QC before it goes + + align:start position:0% +the under at the quote QC before it goes + + + align:start position:0% +the under at the quote QC before it goes +out the door so fix the rotor can be a + + align:start position:0% +out the door so fix the rotor can be a + + + align:start position:0% +out the door so fix the rotor can be a +little expensive sometimes but worth it + + align:start position:0% +little expensive sometimes but worth it + + + align:start position:0% +little expensive sometimes but worth it +you know they do maintenance checks + + align:start position:0% +you know they do maintenance checks + + + align:start position:0% +you know they do maintenance checks +actually they have accelerometers + + align:start position:0% +actually they have accelerometers + + + align:start position:0% +actually they have accelerometers +built-in to all expensive rotating + + align:start position:0% +built-in to all expensive rotating + + + align:start position:0% +built-in to all expensive rotating +equipment these days it's called + + align:start position:0% +equipment these days it's called + + + align:start position:0% +equipment these days it's called +condition monitoring and when they get + + align:start position:0% +condition monitoring and when they get + + + align:start position:0% +condition monitoring and when they get +outside of certain limits + + align:start position:0% +outside of certain limits + + + align:start position:0% +outside of certain limits +shut the thing down and rebuild it + + align:start position:0% +shut the thing down and rebuild it + + + align:start position:0% +shut the thing down and rebuild it +electric generator sets gas turbines jet + + align:start position:0% +electric generator sets gas turbines jet + + + align:start position:0% +electric generator sets gas turbines jet +engines on all aircraft are all + + align:start position:0% +engines on all aircraft are all + + + align:start position:0% +engines on all aircraft are all +incredibly carefully balancing they + + align:start position:0% +incredibly carefully balancing they + + + align:start position:0% +incredibly carefully balancing they +start getting out of balance they stop + + align:start position:0% +start getting out of balance they stop + + + align:start position:0% +start getting out of balance they stop +and fix them before the things blow up + + align:start position:0% +and fix them before the things blow up + + + align:start position:0% +and fix them before the things blow up +on them and you have a 20 million dollar + + align:start position:0% +on them and you have a 20 million dollar + + + align:start position:0% +on them and you have a 20 million dollar +problem instead of maybe if $20,000 + + align:start position:0% +problem instead of maybe if $20,000 + + + align:start position:0% +problem instead of maybe if $20,000 +teardown alright so yeah if you fix the + + align:start position:0% +teardown alright so yeah if you fix the + + + align:start position:0% +teardown alright so yeah if you fix the +rotor third idea + + align:start position:0% + + + + align:start position:0% + +well could you this thing shaking like + + align:start position:0% +well could you this thing shaking like + + + align:start position:0% +well could you this thing shaking like +crazy what if you put it what if you + + align:start position:0% +crazy what if you put it what if you + + + align:start position:0% +crazy what if you put it what if you +change the length of this beam would it + + align:start position:0% +change the length of this beam would it + + + align:start position:0% +change the length of this beam would it +could you stop this thing from shaking + + align:start position:0% +could you stop this thing from shaking + + + align:start position:0% +could you stop this thing from shaking +so much if you stop this I'm shaking so + + align:start position:0% +so much if you stop this I'm shaking so + + + align:start position:0% +so much if you stop this I'm shaking so +much what it puts so much excitation + + align:start position:0% +much what it puts so much excitation + + + align:start position:0% +much what it puts so much excitation +into the table no so treat fix the rotor + + align:start position:0% +into the table no so treat fix the rotor + + + align:start position:0% +into the table no so treat fix the rotor +isolate the source isolate the receiver + + align:start position:0% +isolate the source isolate the receiver + + + align:start position:0% +isolate the source isolate the receiver +now you get at least three ways and the + + align:start position:0% +now you get at least three ways and the + + + align:start position:0% +now you get at least three ways and the +gentleman up here came up with a fourth + + align:start position:0% +gentleman up here came up with a fourth + + + align:start position:0% +gentleman up here came up with a fourth +way active cancellation okay great so + + align:start position:0% +way active cancellation okay great so + + + align:start position:0% +way active cancellation okay great so +let's I have a demo of one of these + + align:start position:0% +let's I have a demo of one of these + + + align:start position:0% +let's I have a demo of one of these +sometimes if you're desperate you're + + align:start position:0% +sometimes if you're desperate you're + + + align:start position:0% +sometimes if you're desperate you're +trying to get some sleep in onto your + + align:start position:0% +trying to get some sleep in onto your + + + align:start position:0% +trying to get some sleep in onto your +bed that's rattling or something you + + align:start position:0% +bed that's rattling or something you + + + align:start position:0% +bed that's rattling or something you +might want to try the following that you + + align:start position:0% +might want to try the following that you + + + align:start position:0% +might want to try the following that you +can do very quickly so we'll dim the + + align:start position:0% +can do very quickly so we'll dim the + + + align:start position:0% +can do very quickly so we'll dim the +lights again we'll turn it back on both + + align:start position:0% +lights again we'll turn it back on both + + + align:start position:0% +lights again we'll turn it back on both +of these things are both are vibrating + + align:start position:0% +of these things are both are vibrating + + + align:start position:0% +of these things are both are vibrating +like crazy alright so one way to detune + + align:start position:0% +like crazy alright so one way to detune + + + align:start position:0% +like crazy alright so one way to detune +the receiver is to put a big weight on + + align:start position:0% +the receiver is to put a big weight on + + + align:start position:0% +the receiver is to put a big weight on +it and change its natural frequency by + + align:start position:0% +it and change its natural frequency by + + + align:start position:0% +it and change its natural frequency by +changing the mass and now the little + + align:start position:0% +changing the mass and now the little + + + align:start position:0% +changing the mass and now the little +thing is hardly shaking at all because + + align:start position:0% +thing is hardly shaking at all because + + + align:start position:0% +thing is hardly shaking at all because +I've detuned it just by switch it's + + align:start position:0% +I've detuned it just by switch it's + + + align:start position:0% +I've detuned it just by switch it's +changing the mass accomplish the same + + align:start position:0% +changing the mass accomplish the same + + + align:start position:0% +changing the mass accomplish the same +thing as change switching the length + + align:start position:0% +thing as change switching the length + + + align:start position:0% +thing as change switching the length +instead of messing with the stiffness + + align:start position:0% +instead of messing with the stiffness + + + align:start position:0% +instead of messing with the stiffness +I've changed the massive system this is + + align:start position:0% +I've changed the massive system this is + + + align:start position:0% +I've changed the massive system this is +still shaking like crazy okay so now + + align:start position:0% +still shaking like crazy okay so now + + + align:start position:0% +still shaking like crazy okay so now +it's back to vibrating again but over + + align:start position:0% +it's back to vibrating again but over + + + align:start position:0% +it's back to vibrating again but over +here is my source I don't know if it'll + + align:start position:0% +here is my source I don't know if it'll + + + align:start position:0% +here is my source I don't know if it'll +work so well in this one because this is + + align:start position:0% +work so well in this one because this is + + + align:start position:0% +work so well in this one because this is +that the source is a lot more massive + + align:start position:0% +that the source is a lot more massive + + + align:start position:0% +that the source is a lot more massive +but I need to put the same mass on it + + align:start position:0% + + + + align:start position:0% + +but made it worse + + align:start position:0% +but made it worse + + + align:start position:0% +but made it worse +ah and that's another good demonstration + + align:start position:0% +ah and that's another good demonstration + + + align:start position:0% +ah and that's another good demonstration +excellent so we could come up back up + + align:start position:0% +excellent so we could come up back up + + + align:start position:0% +excellent so we could come up back up +with the lights you got to be careful of + + align:start position:0% +with the lights you got to be careful of + + + align:start position:0% +with the lights you got to be careful of +that you go to mess with one of these + + align:start position:0% +that you go to mess with one of these + + + align:start position:0% +that you go to mess with one of these +systems if you do it wrong you make the + + align:start position:0% +systems if you do it wrong you make the + + + align:start position:0% +systems if you do it wrong you make the +matter worse first consulting job ever + + align:start position:0% +matter worse first consulting job ever + + + align:start position:0% +matter worse first consulting job ever +had back in 1977 or something like that + + align:start position:0% +had back in 1977 or something like that + + + align:start position:0% +had back in 1977 or something like that +they had a vibration problem on a ship + + align:start position:0% +they had a vibration problem on a ship + + + align:start position:0% +they had a vibration problem on a ship +and the first consultant in said stiffen + + align:start position:0% +and the first consultant in said stiffen + + + align:start position:0% +and the first consultant in said stiffen +up it was actually the exhaust stacks on + + align:start position:0% +up it was actually the exhaust stacks on + + + align:start position:0% +up it was actually the exhaust stacks on +these 5,000 horsepower diesel engines + + align:start position:0% +these 5,000 horsepower diesel engines + + + align:start position:0% +these 5,000 horsepower diesel engines +and they were 30 feet tall and shaking + + align:start position:0% +and they were 30 feet tall and shaking + + + align:start position:0% +and they were 30 feet tall and shaking +like crazy and the first guy said + + align:start position:0% +like crazy and the first guy said + + + align:start position:0% +like crazy and the first guy said +stiffen up those exhaust stacks and he + + align:start position:0% +stiffen up those exhaust stacks and he + + + align:start position:0% +stiffen up those exhaust stacks and he +did exactly the wrong thing and it just + + align:start position:0% +did exactly the wrong thing and it just + + + align:start position:0% +did exactly the wrong thing and it just +shook like worse than ever + + align:start position:0% +shook like worse than ever + + + align:start position:0% +shook like worse than ever +okay so now what what I'm going to show + + align:start position:0% +okay so now what what I'm going to show + + + align:start position:0% +okay so now what what I'm going to show +you will put on the board today is a + + align:start position:0% +you will put on the board today is a + + + align:start position:0% +you will put on the board today is a +little bit of mathematics to back up how + + align:start position:0% +little bit of mathematics to back up how + + + align:start position:0% +little bit of mathematics to back up how +you go about doing the two things one is + + align:start position:0% +you go about doing the two things one is + + + align:start position:0% +you go about doing the two things one is +isolating the receiver or the other ones + + align:start position:0% +isolating the receiver or the other ones + + + align:start position:0% +isolating the receiver or the other ones +isolating the source it will start going + + align:start position:0% +isolating the source it will start going + + + align:start position:0% +isolating the source it will start going +to start with isolating the receiver but + + align:start position:0% +to start with isolating the receiver but + + + align:start position:0% +to start with isolating the receiver but +we're going to start with a little bit + + align:start position:0% +we're going to start with a little bit + + + align:start position:0% +we're going to start with a little bit +of math a little math tool that we need + + align:start position:0% +of math a little math tool that we need + + + align:start position:0% +of math a little math tool that we need +that'll make life a lot easier for us + + align:start position:0% +that'll make life a lot easier for us + + + align:start position:0% +that'll make life a lot easier for us +maybe I'll work here if you recall last + + align:start position:0% +maybe I'll work here if you recall last + + + align:start position:0% +maybe I'll work here if you recall last +time that would be the time to do it we + + align:start position:0% +time that would be the time to do it we + + + align:start position:0% +time that would be the time to do it we +derived the transfer function for a + + align:start position:0% + + + + align:start position:0% + +essentially this system where we had an + + align:start position:0% +essentially this system where we had an + + + align:start position:0% +essentially this system where we had an +F naught cosine Omega T and we computed + + align:start position:0% +F naught cosine Omega T and we computed + + + align:start position:0% +F naught cosine Omega T and we computed +the response X of T at some X naught + + align:start position:0% +the response X of T at some X naught + + + align:start position:0% +the response X of T at some X naught +cosine Omega T - a phase angle and we + + align:start position:0% +cosine Omega T - a phase angle and we + + + align:start position:0% +cosine Omega T - a phase angle and we +worked it all down to where we could + + align:start position:0% +worked it all down to where we could + + + align:start position:0% +worked it all down to where we could +plot it like that but you know quite + + align:start position:0% +plot it like that but you know quite + + + align:start position:0% +plot it like that but you know quite +frankly I mean I'd it was kind of a lot + + align:start position:0% +frankly I mean I'd it was kind of a lot + + + align:start position:0% +frankly I mean I'd it was kind of a lot +of lines of math and it was sort of + + align:start position:0% +of lines of math and it was sort of + + + align:start position:0% +of lines of math and it was sort of +painful I actually hated doing it on the + + align:start position:0% +painful I actually hated doing it on the + + + align:start position:0% +painful I actually hated doing it on the +board but it was easy because it was + + align:start position:0% +board but it was easy because it was + + + align:start position:0% +board but it was easy because it was +familiar it's just trig stuff it was all + + align:start position:0% +familiar it's just trig stuff it was all + + + align:start position:0% +familiar it's just trig stuff it was all +trig and a little bit of calculus and so + + align:start position:0% +trig and a little bit of calculus and so + + + align:start position:0% +trig and a little bit of calculus and so +we do that first because it all makes + + align:start position:0% +we do that first because it all makes + + + align:start position:0% +we do that first because it all makes +sense to you mathematically but there's + + align:start position:0% +sense to you mathematically but there's + + + align:start position:0% +sense to you mathematically but there's +a vastly easier and quicker way to do + + align:start position:0% +a vastly easier and quicker way to do + + + align:start position:0% +a vastly easier and quicker way to do +this which we'll address right now and + + align:start position:0% +this which we'll address right now and + + + align:start position:0% +this which we'll address right now and +that's using complex numbers and the so + + align:start position:0% +that's using complex numbers and the so + + + align:start position:0% +that's using complex numbers and the so +we'll we need a couple of bits of + + align:start position:0% +we'll we need a couple of bits of + + + align:start position:0% +we'll we need a couple of bits of +information here one is Euler's formula + + align:start position:0% + + + + align:start position:0% + +so if you have e raised to the power I + + align:start position:0% +so if you have e raised to the power I + + + align:start position:0% +so if you have e raised to the power I +theta you can show that that is the same + + align:start position:0% +theta you can show that that is the same + + + align:start position:0% +theta you can show that that is the same +thing as cosine theta plus I sine of + + align:start position:0% +thing as cosine theta plus I sine of + + + align:start position:0% +thing as cosine theta plus I sine of +theta that breaks into a real part and + + align:start position:0% +theta that breaks into a real part and + + + align:start position:0% +theta that breaks into a real part and +an imaginary part okay so we wanted to + + align:start position:0% +an imaginary part okay so we wanted to + + + align:start position:0% +an imaginary part okay so we wanted to +express this excitation F naught cosine + + align:start position:0% +express this excitation F naught cosine + + + align:start position:0% +express this excitation F naught cosine +Omega T in complex notation we would say + + align:start position:0% +Omega T in complex notation we would say + + + align:start position:0% +Omega T in complex notation we would say +it is the real part which I denote as re + + align:start position:0% +it is the real part which I denote as re + + + align:start position:0% +it is the real part which I denote as re +the real part of F naught e to the I + + align:start position:0% +the real part of F naught e to the I + + + align:start position:0% +the real part of F naught e to the I +Omega T and I'm going to dispense Phi + + align:start position:0% +Omega T and I'm going to dispense Phi + + + align:start position:0% +Omega T and I'm going to dispense Phi +that F naught itself here this is real + + align:start position:0% +that F naught itself here this is real + + + align:start position:0% +that F naught itself here this is real +and positive + + align:start position:0% + + + + align:start position:0% + +so this this is real and positive so the + + align:start position:0% +so this this is real and positive so the + + + align:start position:0% +so this this is real and positive so the +real part is going to be f naught x and + + align:start position:0% +real part is going to be f naught x and + + + align:start position:0% +real part is going to be f naught x and +if you break down code e to the I Omega + + align:start position:0% +if you break down code e to the I Omega + + + align:start position:0% +if you break down code e to the I Omega +T into its by Euler's formula it gives + + align:start position:0% +T into its by Euler's formula it gives + + + align:start position:0% +T into its by Euler's formula it gives +you cosine Omega T plus I sine Omega T + + align:start position:0% +you cosine Omega T plus I sine Omega T + + + align:start position:0% +you cosine Omega T plus I sine Omega T +and the real part is the cosine part + + align:start position:0% +and the real part is the cosine part + + + align:start position:0% +and the real part is the cosine part +just according to this okay now another + + align:start position:0% +just according to this okay now another + + + align:start position:0% +just according to this okay now another +little fact that I want to show you is + + align:start position:0% +little fact that I want to show you is + + + align:start position:0% +little fact that I want to show you is +if you have a complex number A plus bi I + + align:start position:0% + + + + align:start position:0% + +want to express it as sum c e to the I + + align:start position:0% +want to express it as sum c e to the I + + + align:start position:0% +want to express it as sum c e to the I +theta you want to use Euler's formula to + + align:start position:0% +theta you want to use Euler's formula to + + + align:start position:0% +theta you want to use Euler's formula to +express a complex number and if we draw + + align:start position:0% +express a complex number and if we draw + + + align:start position:0% +express a complex number and if we draw +it the answer becomes pretty obvious + + align:start position:0% +it the answer becomes pretty obvious + + + align:start position:0% +it the answer becomes pretty obvious +this is a point up here a bi this is + + align:start position:0% +this is a point up here a bi this is + + + align:start position:0% +this is a point up here a bi this is +imaginary axis here and the real and + + align:start position:0% +imaginary axis here and the real and + + + align:start position:0% +imaginary axis here and the real and +this point this side is a and this side + + align:start position:0% +this point this side is a and this side + + + align:start position:0% +this point this side is a and this side +here is B and this side here the length + + align:start position:0% +here is B and this side here the length + + + align:start position:0% +here is B and this side here the length +of this triangle is C and the angle in + + align:start position:0% +of this triangle is C and the angle in + + + align:start position:0% +of this triangle is C and the angle in +here is Theta so now if I ask you what's + + align:start position:0% +here is Theta so now if I ask you what's + + + align:start position:0% +here is Theta so now if I ask you what's +C we say oh well C is obviously the + + align:start position:0% +C we say oh well C is obviously the + + + align:start position:0% +C we say oh well C is obviously the +square root of a squared plus B squared + + align:start position:0% +square root of a squared plus B squared + + + align:start position:0% +square root of a squared plus B squared +and theta is a tangent inverse of B over + + align:start position:0% +and theta is a tangent inverse of B over + + + align:start position:0% +and theta is a tangent inverse of B over +a which is the imaginary part over the + + align:start position:0% +a which is the imaginary part over the + + + align:start position:0% +a which is the imaginary part over the +real part + + align:start position:0% + + + + align:start position:0% + +okay so now you can set if you want to + + align:start position:0% +okay so now you can set if you want to + + + align:start position:0% +okay so now you can set if you want to +express a complex number this way well + + align:start position:0% +express a complex number this way well + + + align:start position:0% +express a complex number this way well +the magnitude is square root of a + + align:start position:0% +the magnitude is square root of a + + + align:start position:0% +the magnitude is square root of a +squared plus B squared and the phase + + align:start position:0% +squared plus B squared and the phase + + + align:start position:0% +squared plus B squared and the phase +angle that you put up here is tangent + + align:start position:0% +angle that you put up here is tangent + + + align:start position:0% +angle that you put up here is tangent +inverse of the imaginary part over the + + align:start position:0% +inverse of the imaginary part over the + + + align:start position:0% +inverse of the imaginary part over the +real okay so now we have the basic tools + + align:start position:0% + + + + align:start position:0% + +we need to take on the vibration problem + + align:start position:0% +we need to take on the vibration problem + + + align:start position:0% +we need to take on the vibration problem +and so we have that system up there and + + align:start position:0% +and so we have that system up there and + + + align:start position:0% +and so we have that system up there and +our output from the way we derived it + + align:start position:0% +our output from the way we derived it + + + align:start position:0% +our output from the way we derived it +last time the output is some X naught + + align:start position:0% +last time the output is some X naught + + + align:start position:0% +last time the output is some X naught +cosine Omega t minus fee + + align:start position:0% +cosine Omega t minus fee + + + align:start position:0% +cosine Omega t minus fee +one of the reasons it was so painful + + align:start position:0% +one of the reasons it was so painful + + + align:start position:0% +one of the reasons it was so painful +doing it this way last time is you have + + align:start position:0% +doing it this way last time is you have + + + align:start position:0% +doing it this way last time is you have +to this is cosine as a functionable time + + align:start position:0% +to this is cosine as a functionable time + + + align:start position:0% +to this is cosine as a functionable time +and phase and to break it apart takes a + + align:start position:0% +and phase and to break it apart takes a + + + align:start position:0% +and phase and to break it apart takes a +lot of work so we want to do the same + + align:start position:0% +lot of work so we want to do the same + + + align:start position:0% +lot of work so we want to do the same +thing but with complex variables this + + align:start position:0% +thing but with complex variables this + + + align:start position:0% +thing but with complex variables this +time so I want to express this then as + + align:start position:0% +time so I want to express this then as + + + align:start position:0% +time so I want to express this then as +the real part of I could say it's the + + align:start position:0% +the real part of I could say it's the + + + align:start position:0% +the real part of I could say it's the +real part of X naught e to the I Omega t + + align:start position:0% +real part of X naught e to the I Omega t + + + align:start position:0% +real part of X naught e to the I Omega t +minus V and just by Euler's formula if + + align:start position:0% +minus V and just by Euler's formula if + + + align:start position:0% +minus V and just by Euler's formula if +this is real just a number then this + + align:start position:0% +this is real just a number then this + + + align:start position:0% +this is real just a number then this +breaks down into cosine Omega t minus V + + align:start position:0% +breaks down into cosine Omega t minus V + + + align:start position:0% +breaks down into cosine Omega t minus V +and I sine Omega T mine + + align:start position:0% +and I sine Omega T mine + + + align:start position:0% +and I sine Omega T mine +minus V but here's the beauty of using + + align:start position:0% +minus V but here's the beauty of using + + + align:start position:0% +minus V but here's the beauty of using +complex notation and Exponential's this + + align:start position:0% +complex notation and Exponential's this + + + align:start position:0% +complex notation and Exponential's this +now becomes the real part of X naught e + + align:start position:0% +now becomes the real part of X naught e + + + align:start position:0% +now becomes the real part of X naught e +to the minus I P times e to the I Omega + + align:start position:0% +to the minus I P times e to the I Omega + + + align:start position:0% +to the minus I P times e to the I Omega +T I can separate these two and this is + + align:start position:0% +T I can separate these two and this is + + + align:start position:0% +T I can separate these two and this is +what makes it so much easier to use this + + align:start position:0% +what makes it so much easier to use this + + + align:start position:0% +what makes it so much easier to use this +approach and I'm going to call + + align:start position:0% +approach and I'm going to call + + + align:start position:0% +approach and I'm going to call +this part of it just some capital X and + + align:start position:0% +this part of it just some capital X and + + + align:start position:0% +this part of it just some capital X and +it is a complex number for sure I break + + align:start position:0% +it is a complex number for sure I break + + + align:start position:0% +it is a complex number for sure I break +this up into cosine V cosine of minus V + + align:start position:0% +this up into cosine V cosine of minus V + + + align:start position:0% +this up into cosine V cosine of minus V +and minus I sine V it's got an IEEE sign + + align:start position:0% +and minus I sine V it's got an IEEE sign + + + align:start position:0% +and minus I sine V it's got an IEEE sign +fees this got this is a complex number a + + align:start position:0% +fees this got this is a complex number a + + + align:start position:0% +fees this got this is a complex number a ++ bi kind of form so in general this + + align:start position:0% ++ bi kind of form so in general this + + + align:start position:0% ++ bi kind of form so in general this +thing is complex so this whole thing is + + align:start position:0% +thing is complex so this whole thing is + + + align:start position:0% +thing is complex so this whole thing is +the real part of some X which I don't + + align:start position:0% +the real part of some X which I don't + + + align:start position:0% +the real part of some X which I don't +know now e to the I Omega T so now we + + align:start position:0% +know now e to the I Omega T so now we + + + align:start position:0% +know now e to the I Omega T so now we +can quickly quite quickly do this the + + align:start position:0% +can quickly quite quickly do this the + + + align:start position:0% +can quickly quite quickly do this the +derivation we did last time we're + + align:start position:0% +derivation we did last time we're + + + align:start position:0% +derivation we did last time we're +talking about representing linear + + align:start position:0% +talking about representing linear + + + align:start position:0% +talking about representing linear +systems by some kind of black box as a + + align:start position:0% +systems by some kind of black box as a + + + align:start position:0% +systems by some kind of black box as a +transfer function in it which we call H + + align:start position:0% +transfer function in it which we call H + + + align:start position:0% +transfer function in it which we call H +in this case X F response X per unit + + align:start position:0% +in this case X F response X per unit + + + align:start position:0% +in this case X F response X per unit +input F remember we're talking about + + align:start position:0% +input F remember we're talking about + + + align:start position:0% +input F remember we're talking about +steady state response only and we have + + align:start position:0% +steady state response only and we have + + + align:start position:0% +steady state response only and we have +as our input here some F naught e to the + + align:start position:0% +as our input here some F naught e to the + + + align:start position:0% +as our input here some F naught e to the +I Omega T and we have as an output some + + align:start position:0% +I Omega T and we have as an output some + + + align:start position:0% +I Omega T and we have as an output some +X e to the I Omega T we know that we're + + align:start position:0% +X e to the I Omega T we know that we're + + + align:start position:0% +X e to the I Omega T we know that we're +going to use the convention that we care + + align:start position:0% +going to use the convention that we care + + + align:start position:0% +going to use the convention that we care +about this is we have to have real + + align:start position:0% +about this is we have to have real + + + align:start position:0% +about this is we have to have real +answers real number answers so we'll be + + align:start position:0% +answers real number answers so we'll be + + + align:start position:0% +answers real number answers so we'll be +using eventually to be actually using + + align:start position:0% +using eventually to be actually using + + + align:start position:0% +using eventually to be actually using +the real part of the input and the real + + align:start position:0% +the real part of the input and the real + + + align:start position:0% +the real part of the input and the real +part of the output but to get there + + align:start position:0% +part of the output but to get there + + + align:start position:0% +part of the output but to get there +we're going to use complex notation + + align:start position:0% +we're going to use complex notation + + + align:start position:0% +we're going to use complex notation +first and separate out the real and + + align:start position:0% +first and separate out the real and + + + align:start position:0% +first and separate out the real and +imaginary parts at the end + + align:start position:0% + + + + align:start position:0% + +so for our system it we know the + + align:start position:0% +so for our system it we know the + + + align:start position:0% +so for our system it we know the +equation of motion so now it's some F + + align:start position:0% +equation of motion so now it's some F + + + align:start position:0% +equation of motion so now it's some F +naught e to the I Omega T there's our + + align:start position:0% +naught e to the I Omega T there's our + + + align:start position:0% +naught e to the I Omega T there's our +equation of motion and I'm going to let + + align:start position:0% +equation of motion and I'm going to let + + + align:start position:0% +equation of motion and I'm going to let +X here be this unknown capital X e to + + align:start position:0% +X here be this unknown capital X e to + + + align:start position:0% +X here be this unknown capital X e to +the I Omega T and I'm going to plug it + + align:start position:0% +the I Omega T and I'm going to plug it + + + align:start position:0% +the I Omega T and I'm going to plug it +in and the Exponential's are + + align:start position:0% +in and the Exponential's are + + + align:start position:0% +in and the Exponential's are +particularly easy to deal with when + + align:start position:0% +particularly easy to deal with when + + + align:start position:0% +particularly easy to deal with when +you're taking derivatives so upon doing + + align:start position:0% +you're taking derivatives so upon doing + + + align:start position:0% +you're taking derivatives so upon doing +that we immediately get minus Omega + + align:start position:0% +that we immediately get minus Omega + + + align:start position:0% +that we immediately get minus Omega +squared M plus I Omega C plus K all of + + align:start position:0% +squared M plus I Omega C plus K all of + + + align:start position:0% +squared M plus I Omega C plus K all of +that times X e to the I Omega T equals F + + align:start position:0% +that times X e to the I Omega T equals F + + + align:start position:0% +that times X e to the I Omega T equals F +naught e to the I Omega T and right + + align:start position:0% +naught e to the I Omega T and right + + + align:start position:0% +naught e to the I Omega T and right +immediately I can get rid of the + + align:start position:0% +immediately I can get rid of the + + + align:start position:0% +immediately I can get rid of the +time-dependent parts and I can solve for + + align:start position:0% +time-dependent parts and I can solve for + + + align:start position:0% +time-dependent parts and I can solve for +x over F which is what we went out we'll + + align:start position:0% +x over F which is what we went out we'll + + + align:start position:0% +x over F which is what we went out we'll +set out to do the other day to find this + + align:start position:0% +set out to do the other day to find this + + + align:start position:0% +set out to do the other day to find this +transfer function between input and + + align:start position:0% +transfer function between input and + + + align:start position:0% +transfer function between input and +output + + align:start position:0% + + + + align:start position:0% + +so I'm if I solve for X divided by F I'm + + align:start position:0% +so I'm if I solve for X divided by F I'm + + + align:start position:0% +so I'm if I solve for X divided by F I'm +going to get all this stuff in the + + align:start position:0% +going to get all this stuff in the + + + align:start position:0% +going to get all this stuff in the +denominator on one side and I'll write + + align:start position:0% +denominator on one side and I'll write + + + align:start position:0% +denominator on one side and I'll write +it out here simply looks like that and + + align:start position:0% +it out here simply looks like that and + + + align:start position:0% +it out here simply looks like that and +now remember I can substitute in some + + align:start position:0% +now remember I can substitute in some + + + align:start position:0% +now remember I can substitute in some +things remember K over m is Omega N + + align:start position:0% +things remember K over m is Omega N + + + align:start position:0% +things remember K over m is Omega N +squared and Zeta is C over 2 Omega n M I + + align:start position:0% +squared and Zeta is C over 2 Omega n M I + + + align:start position:0% +squared and Zeta is C over 2 Omega n M I +plug those things in and just rearrange + + align:start position:0% +plug those things in and just rearrange + + + align:start position:0% +plug those things in and just rearrange +it a little tiny bit well we come up we + + align:start position:0% +it a little tiny bit well we come up we + + + align:start position:0% +it a little tiny bit well we come up we +should come up with something like we + + align:start position:0% +should come up with something like we + + + align:start position:0% +should come up with something like we +found before so that x over F 1 over K + + align:start position:0% + + + + align:start position:0% + +denominator 1 minus Omega squared over + + align:start position:0% +denominator 1 minus Omega squared over + + + align:start position:0% +denominator 1 minus Omega squared over +Omega N squared + + align:start position:0% +Omega N squared + + + align:start position:0% +Omega N squared +not quite yet here plus 2i Zeta Omega + + align:start position:0% +not quite yet here plus 2i Zeta Omega + + + align:start position:0% +not quite yet here plus 2i Zeta Omega +over Omega n that's what it looks like + + align:start position:0% + + + + align:start position:0% + +so you still have a complex denominator + + align:start position:0% + + + + align:start position:0% + +and this basically looks like a number 1 + + align:start position:0% +and this basically looks like a number 1 + + + align:start position:0% +and this basically looks like a number 1 +over K times 1 over some a plus bi + + align:start position:0% + + + + align:start position:0% + +there's a term it should be i-10 + + align:start position:0% + + + + align:start position:0% + +if I multiply and the way you deal with + + align:start position:0% +if I multiply and the way you deal with + + + align:start position:0% +if I multiply and the way you deal with +something like this you have an A plus + + align:start position:0% +something like this you have an A plus + + + align:start position:0% +something like this you have an A plus +bi in the denominator you multiply the + + align:start position:0% +bi in the denominator you multiply the + + + align:start position:0% +bi in the denominator you multiply the +numerator and denominator by the complex + + align:start position:0% +numerator and denominator by the complex + + + align:start position:0% +numerator and denominator by the complex +conjugate I want to get this into + + align:start position:0% +conjugate I want to get this into + + + align:start position:0% +conjugate I want to get this into +actually standard a plus bi form + + align:start position:0% +actually standard a plus bi form + + + align:start position:0% +actually standard a plus bi form +so I can if I do that symbolically here + + align:start position:0% +so I can if I do that symbolically here + + + align:start position:0% +so I can if I do that symbolically here +it comes out looking like a minus bi + + align:start position:0% +it comes out looking like a minus bi + + + align:start position:0% +it comes out looking like a minus bi +over a squared plus B squared that's 1 + + align:start position:0% +over a squared plus B squared that's 1 + + + align:start position:0% +over a squared plus B squared that's 1 +over K e to the minus I fee over a + + align:start position:0% +over K e to the minus I fee over a + + + align:start position:0% +over K e to the minus I fee over a +square root of a squared plus B squared + + align:start position:0% + + + + align:start position:0% + +because now see this is just a real + + align:start position:0% +because now see this is just a real + + + align:start position:0% +because now see this is just a real +denominator is just a real number so + + align:start position:0% +denominator is just a real number so + + + align:start position:0% +denominator is just a real number so +this whole thing is in some form c plus + + align:start position:0% +this whole thing is in some form c plus + + + align:start position:0% +this whole thing is in some form c plus +a di account you could break this into a + + align:start position:0% +a di account you could break this into a + + + align:start position:0% +a di account you could break this into a +real part complex part we could say + + align:start position:0% +real part complex part we could say + + + align:start position:0% +real part complex part we could say +that's equal to some magnitude times a + + align:start position:0% +that's equal to some magnitude times a + + + align:start position:0% +that's equal to some magnitude times a +eetu the I fee and the magnitude to get + + align:start position:0% +eetu the I fee and the magnitude to get + + + align:start position:0% +eetu the I fee and the magnitude to get +the magnitude you multiply they you take + + align:start position:0% +the magnitude you multiply they you take + + + align:start position:0% +the magnitude you multiply they you take +a squared plus b squared square root it + + align:start position:0% +a squared plus b squared square root it + + + align:start position:0% +a squared plus b squared square root it +cancels this is this is squared the + + align:start position:0% +cancels this is this is squared the + + + align:start position:0% +cancels this is this is squared the +denominator to end up with this part + + align:start position:0% +denominator to end up with this part + + + align:start position:0% +denominator to end up with this part +square root in the denominator this is + + align:start position:0% +square root in the denominator this is + + + align:start position:0% +square root in the denominator this is +what the we need to know what fee looks + + align:start position:0% +what the we need to know what fee looks + + + align:start position:0% +what the we need to know what fee looks +like well feed better come out like + + align:start position:0% +like well feed better come out like + + + align:start position:0% +like well feed better come out like +before we're now fee is minus tangent + + align:start position:0% +before we're now fee is minus tangent + + + align:start position:0% +before we're now fee is minus tangent +inverse of the imaginary part over the + + align:start position:0% +inverse of the imaginary part over the + + + align:start position:0% +inverse of the imaginary part over the +real part and the imaginary part has a + + align:start position:0% +real part and the imaginary part has a + + + align:start position:0% +real part and the imaginary part has a +minus here that's why I minus pops up + + align:start position:0% +minus here that's why I minus pops up + + + align:start position:0% +minus here that's why I minus pops up +here imaginary part comes from this the + + align:start position:0% +here imaginary part comes from this the + + + align:start position:0% +here imaginary part comes from this the +real part comes from there + + align:start position:0% +real part comes from there + + + align:start position:0% +real part comes from there +the common denominator stuff all cancels + + align:start position:0% +the common denominator stuff all cancels + + + align:start position:0% +the common denominator stuff all cancels +out when you take the ratio + + align:start position:0% +out when you take the ratio + + + align:start position:0% +out when you take the ratio +this is tangent inverse of 2 Zeta Omega + + align:start position:0% +this is tangent inverse of 2 Zeta Omega + + + align:start position:0% +this is tangent inverse of 2 Zeta Omega +over Omega n all over 1 minus Omega + + align:start position:0% +over Omega n all over 1 minus Omega + + + align:start position:0% +over Omega n all over 1 minus Omega +squared over Omega N squared as before + + align:start position:0% +squared over Omega N squared as before + + + align:start position:0% +squared over Omega N squared as before +I've skipped a couple steps but we crank + + align:start position:0% +I've skipped a couple steps but we crank + + + align:start position:0% +I've skipped a couple steps but we crank +this whole thing out before this is just + + align:start position:0% +this whole thing out before this is just + + + align:start position:0% +this whole thing out before this is just +this is the same trap steps that you + + align:start position:0% +this is the same trap steps that you + + + align:start position:0% +this is the same trap steps that you +would go through to do that we're just + + align:start position:0% +would go through to do that we're just + + + align:start position:0% +would go through to do that we're just +doing this to get to the phase angle but + + align:start position:0% +doing this to get to the phase angle but + + + align:start position:0% +doing this to get to the phase angle but +this now is exactly the same thing we + + align:start position:0% +this now is exactly the same thing we + + + align:start position:0% +this now is exactly the same thing we +got before which we have plotted up + + align:start position:0% +got before which we have plotted up + + + align:start position:0% +got before which we have plotted up +there we tend to work with the magnitude + + align:start position:0% +there we tend to work with the magnitude + + + align:start position:0% +there we tend to work with the magnitude +we work with magnitude and phase angle + + align:start position:0% +we work with magnitude and phase angle + + + align:start position:0% +we work with magnitude and phase angle +so the magnitude of X over F is the same + + align:start position:0% +so the magnitude of X over F is the same + + + align:start position:0% +so the magnitude of X over F is the same +thing as saying the magnitude of the + + align:start position:0% +thing as saying the magnitude of the + + + align:start position:0% +thing as saying the magnitude of the +transfer function and that transfer + + align:start position:0% +transfer function and that transfer + + + align:start position:0% +transfer function and that transfer +function looks like 1 over K the + + align:start position:0% +function looks like 1 over K the + + + align:start position:0% +function looks like 1 over K the +magnitude all divided by 1 minus Omega + + align:start position:0% +magnitude all divided by 1 minus Omega + + + align:start position:0% +magnitude all divided by 1 minus Omega +squared over Omega N squared squared + + align:start position:0% +squared over Omega N squared squared + + + align:start position:0% +squared over Omega N squared squared +plus 2 Zeta Omega over Omega N squared + + align:start position:0% + + + + align:start position:0% + +square root that is the same transfer + + align:start position:0% +square root that is the same transfer + + + align:start position:0% +square root that is the same transfer +function magnitude that we derived last + + align:start position:0% +function magnitude that we derived last + + + align:start position:0% +function magnitude that we derived last +time with a lot more work and this + + align:start position:0% +time with a lot more work and this + + + align:start position:0% +time with a lot more work and this +approach using complex variables you can + + align:start position:0% +approach using complex variables you can + + + align:start position:0% +approach using complex variables you can +use for any input/output single-input + + align:start position:0% +use for any input/output single-input + + + align:start position:0% +use for any input/output single-input +single-output linear system and we're + + align:start position:0% +single-output linear system and we're + + + align:start position:0% +single-output linear system and we're +going to do it to derive right away the + + align:start position:0% +going to do it to derive right away the + + + align:start position:0% +going to do it to derive right away the +transfer function for the response of + + align:start position:0% +transfer function for the response of + + + align:start position:0% +transfer function for the response of +this to motion of the base + + align:start position:0% + + + + align:start position:0% + +so if you follow how we use this complex + + align:start position:0% +so if you follow how we use this complex + + + align:start position:0% +so if you follow how we use this complex +variables and e to the I Omega T's to + + align:start position:0% +variables and e to the I Omega T's to + + + align:start position:0% +variables and e to the I Omega T's to +get here we can now apply the same tools + + align:start position:0% +get here we can now apply the same tools + + + align:start position:0% +get here we can now apply the same tools +to do other transfer functions to be a + + align:start position:0% +to do other transfer functions to be a + + + align:start position:0% +to do other transfer functions to be a +lot more efficient about it before I + + align:start position:0% +lot more efficient about it before I + + + align:start position:0% +lot more efficient about it before I +jump to this one remind you how in + + align:start position:0% +jump to this one remind you how in + + + align:start position:0% +jump to this one remind you how in +practice we use this so if the statement + + align:start position:0% +practice we use this so if the statement + + + align:start position:0% +practice we use this so if the statement +magnitude of X over F equals everything + + align:start position:0% +magnitude of X over F equals everything + + + align:start position:0% +magnitude of X over F equals everything +on the right there then in the way we + + align:start position:0% +on the right there then in the way we + + + align:start position:0% +on the right there then in the way we +would normally use this is to say well + + align:start position:0% +would normally use this is to say well + + + align:start position:0% +would normally use this is to say well +if you want the magnitude of the + + align:start position:0% +if you want the magnitude of the + + + align:start position:0% +if you want the magnitude of the +response you take the magnitude of the + + align:start position:0% +response you take the magnitude of the + + + align:start position:0% +response you take the magnitude of the +input force multiply it by the magnitude + + align:start position:0% +input force multiply it by the magnitude + + + align:start position:0% +input force multiply it by the magnitude +of the transfer function evaluated at + + align:start position:0% +of the transfer function evaluated at + + + align:start position:0% +of the transfer function evaluated at +the correct frequency that would give + + align:start position:0% +the correct frequency that would give + + + align:start position:0% +the correct frequency that would give +you the magnitude if you want the time + + align:start position:0% +you the magnitude if you want the time + + + align:start position:0% +you the magnitude if you want the time +dependence X of T well it's the + + align:start position:0% +dependence X of T well it's the + + + align:start position:0% +dependence X of T well it's the +magnitude of the force magnitude of the + + align:start position:0% +magnitude of the force magnitude of the + + + align:start position:0% +magnitude of the force magnitude of the +transfer function times the real part of + + align:start position:0% +transfer function times the real part of + + + align:start position:0% +transfer function times the real part of +e to the I Omega t minus V and this gets + + align:start position:0% +e to the I Omega t minus V and this gets + + + align:start position:0% +e to the I Omega t minus V and this gets +us back to when you work this out this + + align:start position:0% +us back to when you work this out this + + + align:start position:0% +us back to when you work this out this +is your X naught and this is your cosine + + align:start position:0% +is your X naught and this is your cosine + + + align:start position:0% +is your X naught and this is your cosine +Omega t minus V + + align:start position:0% + + + + align:start position:0% + +so once you know what the excitation + + align:start position:0% +so once you know what the excitation + + + align:start position:0% +so once you know what the excitation +force is and its frequency + + align:start position:0% +force is and its frequency + + + align:start position:0% +force is and its frequency +put the force in here you valuate that + + align:start position:0% +put the force in here you valuate that + + + align:start position:0% +put the force in here you valuate that +thing on the left at the correct + + align:start position:0% +thing on the left at the correct + + + align:start position:0% +thing on the left at the correct +frequency write out the answer directly + + align:start position:0% +frequency write out the answer directly + + + align:start position:0% +frequency write out the answer directly +and one of the homeworks for today we + + align:start position:0% +and one of the homeworks for today we + + + align:start position:0% +and one of the homeworks for today we +just had just the question just had you + + align:start position:0% +just had just the question just had you + + + align:start position:0% +just had just the question just had you +go through the exercise of figuring this + + align:start position:0% +go through the exercise of figuring this + + + align:start position:0% +go through the exercise of figuring this +out at three different frequency ratios + + align:start position:0% +out at three different frequency ratios + + + align:start position:0% +out at three different frequency ratios +like 1/2 1 & 3 or something like that + + align:start position:0% +like 1/2 1 & 3 or something like that + + + align:start position:0% +like 1/2 1 & 3 or something like that +would put you to the left of the peak at + + align:start position:0% +would put you to the left of the peak at + + + align:start position:0% +would put you to the left of the peak at +1/2 on the peak at 1 and way off to the + + align:start position:0% +1/2 on the peak at 1 and way off to the + + + align:start position:0% +1/2 on the peak at 1 and way off to the +right out at the right edge at 3 and + + align:start position:0% +right out at the right edge at 3 and + + + align:start position:0% +right out at the right edge at 3 and +you'll get three different response + + align:start position:0% +you'll get three different response + + + align:start position:0% +you'll get three different response +amplitudes and three different phase + + align:start position:0% +amplitudes and three different phase + + + align:start position:0% +amplitudes and three different phase +angles that go with it all right so + + align:start position:0% +angles that go with it all right so + + + align:start position:0% +angles that go with it all right so +that's the review did the same thing a + + align:start position:0% +that's the review did the same thing a + + + align:start position:0% +that's the review did the same thing a +different way and I'm going to move on + + align:start position:0% +different way and I'm going to move on + + + align:start position:0% +different way and I'm going to move on +to base motion but any questions about + + align:start position:0% +to base motion but any questions about + + + align:start position:0% +to base motion but any questions about +this now yeah yes + + align:start position:0% + + + + align:start position:0% + +the very top expression up there we want + + align:start position:0% +the very top expression up there we want + + + align:start position:0% +the very top expression up there we want +it says x over F and says we're trying + + align:start position:0% +it says x over F and says we're trying + + + align:start position:0% +it says x over F and says we're trying +to cast it in e to the minus IP form + + align:start position:0% +to cast it in e to the minus IP form + + + align:start position:0% +to cast it in e to the minus IP form +that's my goal and I did that because we + + align:start position:0% +that's my goal and I did that because we + + + align:start position:0% +that's my goal and I did that because we +started over here with the problem that + + align:start position:0% +started over here with the problem that + + + align:start position:0% +started over here with the problem that +we had done before where that's the way + + align:start position:0% +we had done before where that's the way + + + align:start position:0% +we had done before where that's the way +we decided to write the answer and it + + align:start position:0% +we decided to write the answer and it + + + align:start position:0% +we decided to write the answer and it +turns out that it's just a convention in + + align:start position:0% +turns out that it's just a convention in + + + align:start position:0% +turns out that it's just a convention in +vibration and vibration engineering that + + align:start position:0% +vibration and vibration engineering that + + + align:start position:0% +vibration and vibration engineering that +authors and people have adopted to + + align:start position:0% +authors and people have adopted to + + + align:start position:0% +authors and people have adopted to +express the phase angle as minus fee it + + align:start position:0% +express the phase angle as minus fee it + + + align:start position:0% +express the phase angle as minus fee it +could have done it as plus fee but so + + align:start position:0% +could have done it as plus fee but so + + + align:start position:0% +could have done it as plus fee but so +when you and you plot the plots like + + align:start position:0% +when you and you plot the plots like + + + align:start position:0% +when you and you plot the plots like +this our fee oh I see you mean it is + + align:start position:0% +this our fee oh I see you mean it is + + + align:start position:0% +this our fee oh I see you mean it is +it's in it's in there before you take + + align:start position:0% +it's in it's in there before you take + + + align:start position:0% +it's in it's in there before you take +its magnitude so the hxf when it is + + align:start position:0% + + + + align:start position:0% + +this here is left in complex notation + + align:start position:0% +this here is left in complex notation + + + align:start position:0% +this here is left in complex notation +and this is this is H X F of Omega and + + align:start position:0% +and this is this is H X F of Omega and + + + align:start position:0% +and this is this is H X F of Omega and +it is it's complex we take its magnitude + + align:start position:0% +it is it's complex we take its magnitude + + + align:start position:0% +it is it's complex we take its magnitude +in it be then the magnitude is not + + align:start position:0% +in it be then the magnitude is not + + + align:start position:0% +in it be then the magnitude is not +complex right and so we take its + + align:start position:0% +complex right and so we take its + + + align:start position:0% +complex right and so we take its +magnitude we get that expression but + + align:start position:0% +magnitude we get that expression but + + + align:start position:0% +magnitude we get that expression but +when we take its magnitude we've thrown + + align:start position:0% +when we take its magnitude we've thrown + + + align:start position:0% +when we take its magnitude we've thrown +away the phase information so we have to + + align:start position:0% +away the phase information so we have to + + + align:start position:0% +away the phase information so we have to +keep it and put it somewhere and so we + + align:start position:0% +keep it and put it somewhere and so we + + + align:start position:0% +keep it and put it somewhere and so we +put it in a the e to the I fee form and + + align:start position:0% +put it in a the e to the I fee form and + + + align:start position:0% +put it in a the e to the I fee form and +I guess I what I could have done here is + + align:start position:0% +I guess I what I could have done here is + + + align:start position:0% +I guess I what I could have done here is +now this is I've taken this is H X F + + align:start position:0% +now this is I've taken this is H X F + + + align:start position:0% +now this is I've taken this is H X F +same thing as x over F in complex form + + align:start position:0% +same thing as x over F in complex form + + + align:start position:0% +same thing as x over F in complex form +and I've chose said ok if I write it + + align:start position:0% +and I've chose said ok if I write it + + + align:start position:0% +and I've chose said ok if I write it +this way I have just said it is a + + align:start position:0% +this way I have just said it is a + + + align:start position:0% +this way I have just said it is a +magnitude times its phase information + + align:start position:0% +magnitude times its phase information + + + align:start position:0% +magnitude times its phase information +I've separated its phase information + + align:start position:0% +I've separated its phase information + + + align:start position:0% +I've separated its phase information +from its magnitude by writing it this + + align:start position:0% +from its magnitude by writing it this + + + align:start position:0% +from its magnitude by writing it this +way okay and the phase then is that and + + align:start position:0% +way okay and the phase then is that and + + + align:start position:0% +way okay and the phase then is that and +its magnitude is that good question all + + align:start position:0% +its magnitude is that good question all + + + align:start position:0% +its magnitude is that good question all +right + + align:start position:0% + + + + align:start position:0% + +so now let's see if we can kind of + + align:start position:0% +so now let's see if we can kind of + + + align:start position:0% +so now let's see if we can kind of +pretty quickly do the same problem for + + align:start position:0% +pretty quickly do the same problem for + + + align:start position:0% +pretty quickly do the same problem for +base motion so this is our microscope + + align:start position:0% +base motion so this is our microscope + + + align:start position:0% +base motion so this is our microscope +now idealizes a mass spring system + + align:start position:0% +now idealizes a mass spring system + + + align:start position:0% +now idealizes a mass spring system +so this is our microscope has some mass + + align:start position:0% +so this is our microscope has some mass + + + align:start position:0% +so this is our microscope has some mass +stiffness damping motion X of T and how + + align:start position:0% +stiffness damping motion X of T and how + + + align:start position:0% +stiffness damping motion X of T and how +do you suppose that and where do you + + align:start position:0% +do you suppose that and where do you + + + align:start position:0% +do you suppose that and where do you +where would you measure that motion X of + + align:start position:0% +where would you measure that motion X of + + + align:start position:0% +where would you measure that motion X of +T from have to define your coordinate + + align:start position:0% +T from have to define your coordinate + + + align:start position:0% +T from have to define your coordinate +here just there's a major point in the + + align:start position:0% +here just there's a major point in the + + + align:start position:0% +here just there's a major point in the +last known work it's gravity involved + + align:start position:0% +last known work it's gravity involved + + + align:start position:0% +last known work it's gravity involved +but only as a constant term mg and the + + align:start position:0% +but only as a constant term mg and the + + + align:start position:0% +but only as a constant term mg and the +equation of motion it's only there if + + align:start position:0% +equation of motion it's only there if + + + align:start position:0% +equation of motion it's only there if +you depending on how you if you write + + align:start position:0% +you depending on how you if you write + + + align:start position:0% +you depending on how you if you write +the equation of motion in the less + + align:start position:0% +the equation of motion in the less + + + align:start position:0% +the equation of motion in the less +desirable way where is this measured + + align:start position:0% +desirable way where is this measured + + + align:start position:0% +desirable way where is this measured +from do you guess equilibrium position + + align:start position:0% +from do you guess equilibrium position + + + align:start position:0% +from do you guess equilibrium position +static equilibrium position or zero + + align:start position:0% +static equilibrium position or zero + + + align:start position:0% +static equilibrium position or zero +spring force position how many suggest + + align:start position:0% +spring force position how many suggest + + + align:start position:0% +spring force position how many suggest +zero spring force position how many + + align:start position:0% +zero spring force position how many + + + align:start position:0% +zero spring force position how many +suggests static equilibrium okay you got + + align:start position:0% +suggests static equilibrium okay you got + + + align:start position:0% +suggests static equilibrium okay you got +the message this is static this is from + + align:start position:0% +the message this is static this is from + + + align:start position:0% +the message this is static this is from +equilibrium because you know you don't + + align:start position:0% +equilibrium because you know you don't + + + align:start position:0% +equilibrium because you know you don't +deal with the mg term so this is from + + align:start position:0% +deal with the mg term so this is from + + + align:start position:0% +deal with the mg term so this is from +measured from equilibrium + + align:start position:0% +measured from equilibrium + + + align:start position:0% +measured from equilibrium +that's the deflection of the microscope + + align:start position:0% +that's the deflection of the microscope + + + align:start position:0% +that's the deflection of the microscope +support this is the deflection of the + + align:start position:0% +support this is the deflection of the + + + align:start position:0% +support this is the deflection of the +floor that's driving it we know we've + + align:start position:0% +floor that's driving it we know we've + + + align:start position:0% +floor that's driving it we know we've +got that table shaking like crazy that's + + align:start position:0% +got that table shaking like crazy that's + + + align:start position:0% +got that table shaking like crazy that's +what's causing this to vibrate and we + + align:start position:0% +what's causing this to vibrate and we + + + align:start position:0% +what's causing this to vibrate and we +need a Freebody diagram and we approach + + align:start position:0% +need a Freebody diagram and we approach + + + align:start position:0% +need a Freebody diagram and we approach +Freebody diagrams just like before you + + align:start position:0% +Freebody diagrams just like before you + + + align:start position:0% +Freebody diagrams just like before you +imagine positive motions of X and X dot + + align:start position:0% +imagine positive motions of X and X dot + + + align:start position:0% +imagine positive motions of X and X dot +positive motions of Y and y dot and + + align:start position:0% +positive motions of Y and y dot and + + + align:start position:0% +positive motions of Y and y dot and +deduce their forces so a positive x + + align:start position:0% +deduce their forces so a positive x + + + align:start position:0% +deduce their forces so a positive x +gives you a KX opposing a positive X dot + + align:start position:0% +gives you a KX opposing a positive X dot + + + align:start position:0% +gives you a KX opposing a positive X dot +gives you a CX dot opposing a positive Y + + align:start position:0% +gives you a CX dot opposing a positive Y + + + align:start position:0% +gives you a CX dot opposing a positive Y +gives you what the force the results on + + align:start position:0% +gives you what the force the results on + + + align:start position:0% +gives you what the force the results on +this positive motion of the floor + + align:start position:0% + + + + align:start position:0% + +positive or negative force how many + + align:start position:0% +positive or negative force how many + + + align:start position:0% +positive or negative force how many +think positive how many think negative + + align:start position:0% +think positive how many think negative + + + align:start position:0% +think positive how many think negative +we aren't sure how many aren't awake + + align:start position:0% +we aren't sure how many aren't awake + + + align:start position:0% +we aren't sure how many aren't awake +okay look if I push up on this and now + + align:start position:0% +okay look if I push up on this and now + + + align:start position:0% +okay look if I push up on this and now +this is fixed when you do this mental + + align:start position:0% +this is fixed when you do this mental + + + align:start position:0% +this is fixed when you do this mental +experiment you fix this momentarily you + + align:start position:0% +experiment you fix this momentarily you + + + align:start position:0% +experiment you fix this momentarily you +cause a positive deflection here it + + align:start position:0% +cause a positive deflection here it + + + align:start position:0% +cause a positive deflection here it +compresses the spring there's a spring + + align:start position:0% +compresses the spring there's a spring + + + align:start position:0% +compresses the spring there's a spring +push back or not so if I'm moving + + align:start position:0% +push back or not so if I'm moving + + + align:start position:0% +push back or not so if I'm moving +upwards which way is a spring pushing + + align:start position:0% +upwards which way is a spring pushing + + + align:start position:0% +upwards which way is a spring pushing +all right so the but if I'm pushing + + align:start position:0% +all right so the but if I'm pushing + + + align:start position:0% +all right so the but if I'm pushing +upwards which way is the spring pushing + + align:start position:0% +upwards which way is the spring pushing + + + align:start position:0% +upwards which way is the spring pushing +on the mass up so this one gives me a KY + + align:start position:0% +on the mass up so this one gives me a KY + + + align:start position:0% +on the mass up so this one gives me a KY +up and the dashpot does a similar thing + + align:start position:0% +up and the dashpot does a similar thing + + + align:start position:0% +up and the dashpot does a similar thing +see y dot up and there's also an mg here + + align:start position:0% +see y dot up and there's also an mg here + + + align:start position:0% +see y dot up and there's also an mg here +but there's also a K X static if you + + align:start position:0% +but there's also a K X static if you + + + align:start position:0% +but there's also a K X static if you +will up and they cancel we know that so + + align:start position:0% +will up and they cancel we know that so + + + align:start position:0% +will up and they cancel we know that so +we don't have to deal with the mg terms + + align:start position:0% +we don't have to deal with the mg terms + + + align:start position:0% +we don't have to deal with the mg terms +so now we can write our equation of + + align:start position:0% +so now we can write our equation of + + + align:start position:0% +so now we can write our equation of +motion in the equation of motion for + + align:start position:0% +motion in the equation of motion for + + + align:start position:0% +motion in the equation of motion for +this system is the mass times the + + align:start position:0% +this system is the mass times the + + + align:start position:0% +this system is the mass times the +acceleration has got to equal to the sum + + align:start position:0% +acceleration has got to equal to the sum + + + align:start position:0% +acceleration has got to equal to the sum +of all the external forces one two three + + align:start position:0% +of all the external forces one two three + + + align:start position:0% +of all the external forces one two three +four of them and I'll just to save a + + align:start position:0% +four of them and I'll just to save a + + + align:start position:0% +four of them and I'll just to save a +little time and board space I'll put + + align:start position:0% +little time and board space I'll put + + + align:start position:0% +little time and board space I'll put +them in the on the correct sides of the + + align:start position:0% +them in the on the correct sides of the + + + align:start position:0% +them in the on the correct sides of the +equation so this these are the X put the + + align:start position:0% +equation so this these are the X put the + + + align:start position:0% +equation so this these are the X put the +X terms on the left side CX dot plus KX + + align:start position:0% +X terms on the left side CX dot plus KX + + + align:start position:0% +X terms on the left side CX dot plus KX +and on the right hand side I get KY plus + + align:start position:0% +and on the right hand side I get KY plus + + + align:start position:0% +and on the right hand side I get KY plus +CY dot + + align:start position:0% +CY dot + + + align:start position:0% +CY dot +this is my excitation that's the floor + + align:start position:0% +this is my excitation that's the floor + + + align:start position:0% +this is my excitation that's the floor +motion and this is my response on the + + align:start position:0% +motion and this is my response on the + + + align:start position:0% +motion and this is my response on the +left-hand side so I'm going to let Y of + + align:start position:0% +left-hand side so I'm going to let Y of + + + align:start position:0% +left-hand side so I'm going to let Y of +T the input be some Y not real positive + + align:start position:0% +T the input be some Y not real positive + + + align:start position:0% +T the input be some Y not real positive +times e to the I Omega T and I'm going + + align:start position:0% +times e to the I Omega T and I'm going + + + align:start position:0% +times e to the I Omega T and I'm going +to assume that the response is some X + + align:start position:0% +to assume that the response is some X + + + align:start position:0% +to assume that the response is some X +probably complex e to the I Omega T so + + align:start position:0% +probably complex e to the I Omega T so + + + align:start position:0% +probably complex e to the I Omega T so +this is X of T here equals some X I + + align:start position:0% +this is X of T here equals some X I + + + align:start position:0% +this is X of T here equals some X I +don't know e to the I Omega T and I'm + + align:start position:0% +don't know e to the I Omega T and I'm + + + align:start position:0% +don't know e to the I Omega T and I'm +going to plug those two into this + + align:start position:0% +going to plug those two into this + + + align:start position:0% +going to plug those two into this +equation + + align:start position:0% + + + + align:start position:0% + +I just do that directly X is on the left + + align:start position:0% +I just do that directly X is on the left + + + align:start position:0% +I just do that directly X is on the left +side y is on the right side then I find + + align:start position:0% +side y is on the right side then I find + + + align:start position:0% +side y is on the right side then I find +minus Omega squared M plus I Omega C + + align:start position:0% +minus Omega squared M plus I Omega C + + + align:start position:0% +minus Omega squared M plus I Omega C +plus K like before X e to the I Omega T + + align:start position:0% +plus K like before X e to the I Omega T + + + align:start position:0% +plus K like before X e to the I Omega T +equals K plus I Omega C why not e to the + + align:start position:0% +equals K plus I Omega C why not e to the + + + align:start position:0% +equals K plus I Omega C why not e to the +I Omega T and nicely I can for now throw + + align:start position:0% +I Omega T and nicely I can for now throw + + + align:start position:0% +I Omega T and nicely I can for now throw +away get rid of the time dependent part + + align:start position:0% +away get rid of the time dependent part + + + align:start position:0% +away get rid of the time dependent part +and I can solve for response that I'm + + align:start position:0% +and I can solve for response that I'm + + + align:start position:0% +and I can solve for response that I'm +looking for x over the input its real + + align:start position:0% +looking for x over the input its real + + + align:start position:0% +looking for x over the input its real +and positive amplitude of vibration of + + align:start position:0% +and positive amplitude of vibration of + + + align:start position:0% +and positive amplitude of vibration of +the floor and that I will call H x over + + align:start position:0% +the floor and that I will call H x over + + + align:start position:0% +the floor and that I will call H x over +Y of Omega a transfer function probably + + align:start position:0% +Y of Omega a transfer function probably + + + align:start position:0% +Y of Omega a transfer function probably +complex that I can then deal with like I + + align:start position:0% +complex that I can then deal with like I + + + align:start position:0% +complex that I can then deal with like I +did above and when I finish manipulating + + align:start position:0% +did above and when I finish manipulating + + + align:start position:0% +did above and when I finish manipulating +things putting in substituting in Zetas + + align:start position:0% +things putting in substituting in Zetas + + + align:start position:0% +things putting in substituting in Zetas +and Omega n squares and that kind of + + align:start position:0% +and Omega n squares and that kind of + + + align:start position:0% +and Omega n squares and that kind of +thing this becomes well first of all + + align:start position:0% +thing this becomes well first of all + + + align:start position:0% +thing this becomes well first of all +write it this way I can write this as a + + align:start position:0% +write it this way I can write this as a + + + align:start position:0% +write it this way I can write this as a +magnitude times an e to the minus I fee + + align:start position:0% +magnitude times an e to the minus I fee + + + align:start position:0% +magnitude times an e to the minus I fee +again that's what I'm trying that's + + align:start position:0% +again that's what I'm trying that's + + + align:start position:0% +again that's what I'm trying that's +where I want to go + + align:start position:0% + + + + align:start position:0% + +and when I do that one plus little + + align:start position:0% +and when I do that one plus little + + + align:start position:0% +and when I do that one plus little +Messier to Zeta Omega over Omega N + + align:start position:0% +Messier to Zeta Omega over Omega N + + + align:start position:0% +Messier to Zeta Omega over Omega N +squared square root this is just the + + align:start position:0% +squared square root this is just the + + + align:start position:0% +squared square root this is just the +numerator and the denominator + + align:start position:0% +numerator and the denominator + + + align:start position:0% +numerator and the denominator +denominator is just the same as the + + align:start position:0% +denominator is just the same as the + + + align:start position:0% +denominator is just the same as the +other single degree freedom things 1 + + align:start position:0% +other single degree freedom things 1 + + + align:start position:0% +other single degree freedom things 1 +minus Omega squared over Omega N squared + + align:start position:0% +minus Omega squared over Omega N squared + + + align:start position:0% +minus Omega squared over Omega N squared +squared plus 2 Zeta Omega over Omega N + + align:start position:0% +squared plus 2 Zeta Omega over Omega N + + + align:start position:0% +squared plus 2 Zeta Omega over Omega N +squared square root of e to the minus i + + align:start position:0% +squared square root of e to the minus i + + + align:start position:0% +squared square root of e to the minus i +fee so now it's the same it's the same + + align:start position:0% +fee so now it's the same it's the same + + + align:start position:0% +fee so now it's the same it's the same +transfer function as before except the + + align:start position:0% +transfer function as before except the + + + align:start position:0% +transfer function as before except the +denominator is a little little messy and + + align:start position:0% +denominator is a little little messy and + + + align:start position:0% +denominator is a little little messy and +there's no 1 over K and I am going to + + align:start position:0% +there's no 1 over K and I am going to + + + align:start position:0% +there's no 1 over K and I am going to +have a Messier expression for feet here + + align:start position:0% + + + + align:start position:0% + +so there is something wrong with one of + + align:start position:0% +so there is something wrong with one of + + + align:start position:0% +so there is something wrong with one of +the boards this morning + + align:start position:0% + + + + align:start position:0% + +kind of messy complicated do I ever use + + align:start position:0% +kind of messy complicated do I ever use + + + align:start position:0% +kind of messy complicated do I ever use +it rarely provide some of what's + + align:start position:0% +it rarely provide some of what's + + + align:start position:0% +it rarely provide some of what's +important in these things and what isn't + + align:start position:0% +important in these things and what isn't + + + align:start position:0% +important in these things and what isn't +really what's important when you're just + + align:start position:0% +really what's important when you're just + + + align:start position:0% +really what's important when you're just +trying to get a quick solution to + + align:start position:0% +trying to get a quick solution to + + + align:start position:0% +trying to get a quick solution to +vibration isolate something you really + + align:start position:0% +vibration isolate something you really + + + align:start position:0% +vibration isolate something you really +want to know what this going to come out + + align:start position:0% +want to know what this going to come out + + + align:start position:0% +want to know what this going to come out +looking like you're trying to make the + + align:start position:0% +looking like you're trying to make the + + + align:start position:0% +looking like you're trying to make the +response X small compared to the input + + align:start position:0% +response X small compared to the input + + + align:start position:0% +response X small compared to the input +that's the whole objective right now you + + align:start position:0% +that's the whole objective right now you + + + align:start position:0% +that's the whole objective right now you +know the table might be moving a half a + + align:start position:0% +know the table might be moving a half a + + + align:start position:0% +know the table might be moving a half a +millimeter or something like that but + + align:start position:0% +millimeter or something like that but + + + align:start position:0% +millimeter or something like that but +this thing's moving out here you know + + align:start position:0% +this thing's moving out here you know + + + align:start position:0% +this thing's moving out here you know +five or six or seven millimeters so IRA + + align:start position:0% +five or six or seven millimeters so IRA + + + align:start position:0% +five or six or seven millimeters so IRA +ten times that what we'd really like is + + align:start position:0% +ten times that what we'd really like is + + + align:start position:0% +ten times that what we'd really like is +if the tables move in a millimeter you'd + + align:start position:0% +if the tables move in a millimeter you'd + + + align:start position:0% +if the tables move in a millimeter you'd +like this thing out here move in a tenth + + align:start position:0% +like this thing out here move in a tenth + + + align:start position:0% +like this thing out here move in a tenth +of a millimeter and so the real + + align:start position:0% +of a millimeter and so the real + + + align:start position:0% +of a millimeter and so the real +objective here is to make this small + + align:start position:0% +objective here is to make this small + + + align:start position:0% +objective here is to make this small +it's the magnitude you care about phase + + align:start position:0% +it's the magnitude you care about phase + + + align:start position:0% +it's the magnitude you care about phase +you rarely even it really even need to + + align:start position:0% +you rarely even it really even need to + + + align:start position:0% +you rarely even it really even need to +know you want to know or need to know so + + align:start position:0% +know you want to know or need to know so + + + align:start position:0% +know you want to know or need to know so +we're going to do a sample calculation + + align:start position:0% +we're going to do a sample calculation + + + align:start position:0% +we're going to do a sample calculation +into an example here so the source is at + + align:start position:0% +into an example here so the source is at + + + align:start position:0% +into an example here so the source is at +20 Hertz so you're unbalanced pump and + + align:start position:0% +20 Hertz so you're unbalanced pump and + + + align:start position:0% +20 Hertz so you're unbalanced pump and +balanced rotor yeah the same like ah + + align:start position:0% +balanced rotor yeah the same like ah + + + align:start position:0% +balanced rotor yeah the same like ah +what's like why wouldn't it be like + + align:start position:0% +what's like why wouldn't it be like + + + align:start position:0% +what's like why wouldn't it be like +twice that okay that's a great question + + align:start position:0% +twice that okay that's a great question + + + align:start position:0% +twice that okay that's a great question +I haven't mentioned this before and I + + align:start position:0% +I haven't mentioned this before and I + + + align:start position:0% +I haven't mentioned this before and I +and intended to these systems that we're + + align:start position:0% +and intended to these systems that we're + + + align:start position:0% +and intended to these systems that we're +looking at our linear systems what's the + + align:start position:0% +looking at our linear systems what's the + + + align:start position:0% +looking at our linear systems what's the +where we started the other day linear + + align:start position:0% +where we started the other day linear + + + align:start position:0% +where we started the other day linear +systems have some interesting property + + align:start position:0% +systems have some interesting property + + + align:start position:0% +systems have some interesting property +and very useful properties that we + + align:start position:0% +and very useful properties that we + + + align:start position:0% +and very useful properties that we +depend upon one was I said you know one + + align:start position:0% +depend upon one was I said you know one + + + align:start position:0% +depend upon one was I said you know one +force gives you force one gives you + + align:start position:0% +force gives you force one gives you + + + align:start position:0% +force gives you force one gives you +output one force two gives you output to + + align:start position:0% +output one force two gives you output to + + + align:start position:0% +output one force two gives you output to +force one plus two gives you up to some + + align:start position:0% +force one plus two gives you up to some + + + align:start position:0% +force one plus two gives you up to some +of the outputs the other feature of a + + align:start position:0% +of the outputs the other feature of a + + + align:start position:0% +of the outputs the other feature of a +linear system is steady state + + align:start position:0% +linear system is steady state + + + align:start position:0% +linear system is steady state +response after the transience of died + + align:start position:0% +response after the transience of died + + + align:start position:0% +response after the transience of died +away if the frequency of the input is at + + align:start position:0% +away if the frequency of the input is at + + + align:start position:0% +away if the frequency of the input is at +21.5 Hertz the frequency the output is + + align:start position:0% +21.5 Hertz the frequency the output is + + + align:start position:0% +21.5 Hertz the frequency the output is +at 21.5 Hertz period linear systems the + + align:start position:0% +at 21.5 Hertz period linear systems the + + + align:start position:0% +at 21.5 Hertz period linear systems the +frequency of the input is equal to the + + align:start position:0% +frequency of the input is equal to the + + + align:start position:0% +frequency of the input is equal to the +frequency the output that's a really + + align:start position:0% +frequency the output that's a really + + + align:start position:0% +frequency the output that's a really +important little factoid to remember so + + align:start position:0% +important little factoid to remember so + + + align:start position:0% +important little factoid to remember so +I turn on the pump the pumps running at + + align:start position:0% +I turn on the pump the pumps running at + + + align:start position:0% +I turn on the pump the pumps running at +20 Hertz 20 Hertz times 60 is 1200 1200 + + align:start position:0% +20 Hertz 20 Hertz times 60 is 1200 1200 + + + align:start position:0% +20 Hertz 20 Hertz times 60 is 1200 1200 +rpm very common motor speed so the pumps + + align:start position:0% +rpm very common motor speed so the pumps + + + align:start position:0% +rpm very common motor speed so the pumps +mounted at 20 Hertz so that fan it's got + + align:start position:0% +mounted at 20 Hertz so that fan it's got + + + align:start position:0% +mounted at 20 Hertz so that fan it's got +an imbalance so that means you're + + align:start position:0% +an imbalance so that means you're + + + align:start position:0% +an imbalance so that means you're +putting excitation into the floor at 20 + + align:start position:0% +putting excitation into the floor at 20 + + + align:start position:0% +putting excitation into the floor at 20 +Hertz and I want to reduce the vibration + + align:start position:0% + + + + align:start position:0% + +at the microscope by 90% what that + + align:start position:0% +at the microscope by 90% what that + + + align:start position:0% +at the microscope by 90% what that +really means is I my goal is that the + + align:start position:0% +really means is I my goal is that the + + + align:start position:0% +really means is I my goal is that the +magnitude of x over Y is 0.1 that's the + + align:start position:0% +magnitude of x over Y is 0.1 that's the + + + align:start position:0% +magnitude of x over Y is 0.1 that's the +magnitude of this transfer function H Oh + + align:start position:0% +magnitude of this transfer function H Oh + + + align:start position:0% +magnitude of this transfer function H Oh +x over y so I want this transfer + + align:start position:0% +x over y so I want this transfer + + + align:start position:0% +x over y so I want this transfer +function to be 0.1 so just look at the + + align:start position:0% +function to be 0.1 so just look at the + + + align:start position:0% +function to be 0.1 so just look at the +picture can I get that answer to the + + align:start position:0% +picture can I get that answer to the + + + align:start position:0% +picture can I get that answer to the +left of the peak now what this plot + + align:start position:0% +left of the peak now what this plot + + + align:start position:0% +left of the peak now what this plot +shows you is this magnitude of the + + align:start position:0% +shows you is this magnitude of the + + + align:start position:0% +shows you is this magnitude of the +transfer function for a variety of + + align:start position:0% +transfer function for a variety of + + + align:start position:0% +transfer function for a variety of +values of damping of course the lower + + align:start position:0% +values of damping of course the lower + + + align:start position:0% +values of damping of course the lower +the damping the higher the peak gets at + + align:start position:0% +the damping the higher the peak gets at + + + align:start position:0% +the damping the higher the peak gets at +resonance right so no matter what the + + align:start position:0% +resonance right so no matter what the + + + align:start position:0% +resonance right so no matter what the +damping is what is the curves all go to + + align:start position:0% +damping is what is the curves all go to + + + align:start position:0% +damping is what is the curves all go to +on the left-hand side they go to 1 and + + align:start position:0% +on the left-hand side they go to 1 and + + + align:start position:0% +on the left-hand side they go to 1 and +that's really saying the static response + + align:start position:0% +that's really saying the static response + + + align:start position:0% +that's really saying the static response +of this system is if you deflect the + + align:start position:0% +of this system is if you deflect the + + + align:start position:0% +of this system is if you deflect the +floor an inch the table moves with it + + align:start position:0% +floor an inch the table moves with it + + + align:start position:0% +floor an inch the table moves with it +everything goes everything has to move + + align:start position:0% +everything goes everything has to move + + + align:start position:0% +everything goes everything has to move +together when you get down + + align:start position:0% +together when you get down + + + align:start position:0% +together when you get down +to zero frequency input so everything + + align:start position:0% +to zero frequency input so everything + + + align:start position:0% +to zero frequency input so everything +goes to one on the left you go through + + align:start position:0% +goes to one on the left you go through + + + align:start position:0% +goes to one on the left you go through +resonance at natural mega equals the + + align:start position:0% +resonance at natural mega equals the + + + align:start position:0% +resonance at natural mega equals the +natural frequency but on out to the + + align:start position:0% +natural frequency but on out to the + + + align:start position:0% +natural frequency but on out to the +right as the excitation frequency gets + + align:start position:0% +right as the excitation frequency gets + + + align:start position:0% +right as the excitation frequency gets +higher than the natural frequency the + + align:start position:0% +higher than the natural frequency the + + + align:start position:0% +higher than the natural frequency the +response drops off below one which one + + align:start position:0% +response drops off below one which one + + + align:start position:0% +response drops off below one which one +drops the fastest which as you increase + + align:start position:0% +drops the fastest which as you increase + + + align:start position:0% +drops the fastest which as you increase +Omega over mega and beyond one which + + align:start position:0% +Omega over mega and beyond one which + + + align:start position:0% +Omega over mega and beyond one which +Kurt which each of those the whole mess + + align:start position:0% +Kurt which each of those the whole mess + + + align:start position:0% +Kurt which each of those the whole mess +occurs to the right that blend together + + align:start position:0% +occurs to the right that blend together + + + align:start position:0% +occurs to the right that blend together +then they differ only in damping can you + + align:start position:0% +then they differ only in damping can you + + + align:start position:0% +then they differ only in damping can you +tell which one is the let's say if you + + align:start position:0% +tell which one is the let's say if you + + + align:start position:0% +tell which one is the let's say if you +go to at three there the response is at + + align:start position:0% +go to at three there the response is at + + + align:start position:0% +go to at three there the response is at +about 0.14 the lowest curve on that + + align:start position:0% +about 0.14 the lowest curve on that + + + align:start position:0% +about 0.14 the lowest curve on that +curve right and that's the one with no + + align:start position:0% +curve right and that's the one with no + + + align:start position:0% +curve right and that's the one with no +damping little counterintuitive right + + align:start position:0% +damping little counterintuitive right + + + align:start position:0% +damping little counterintuitive right +all right well come back damping does + + align:start position:0% +all right well come back damping does + + + align:start position:0% +all right well come back damping does +help but not heat not at this point so + + align:start position:0% + + + + align:start position:0% + +we we need to find a value of Omega over + + align:start position:0% +we we need to find a value of Omega over + + + align:start position:0% +we we need to find a value of Omega over +Omega n which is greater than one that + + align:start position:0% +Omega n which is greater than one that + + + align:start position:0% +Omega n which is greater than one that +satisfies this + + align:start position:0% + + + + align:start position:0% + +that's what we're after and this is kind + + align:start position:0% +that's what we're after and this is kind + + + align:start position:0% +that's what we're after and this is kind +of messy to work with the easy and I + + align:start position:0% +of messy to work with the easy and I + + + align:start position:0% +of messy to work with the easy and I +sense I know the one that works the best + + align:start position:0% +sense I know the one that works the best + + + align:start position:0% +sense I know the one that works the best +is the one with no damping + + align:start position:0% +is the one with no damping + + + align:start position:0% +is the one with no damping +we'll just so we'll solve the no damping + + align:start position:0% +we'll just so we'll solve the no damping + + + align:start position:0% +we'll just so we'll solve the no damping +one first which makes the algebra really + + align:start position:0% +one first which makes the algebra really + + + align:start position:0% +one first which makes the algebra really +easy and then we can go back and say now + + align:start position:0% +easy and then we can go back and say now + + + align:start position:0% +easy and then we can go back and say now +what happens if you add some damping so + + align:start position:0% +what happens if you add some damping so + + + align:start position:0% +what happens if you add some damping so +for the case there's no damping the + + align:start position:0% +for the case there's no damping the + + + align:start position:0% +for the case there's no damping the +numerator goes to one the denominator + + align:start position:0% +numerator goes to one the denominator + + + align:start position:0% +numerator goes to one the denominator +goes to just 1 over 1 minus Omega + + align:start position:0% +goes to just 1 over 1 minus Omega + + + align:start position:0% +goes to just 1 over 1 minus Omega +squared over Omega N squared so it + + align:start position:0% +squared over Omega N squared so it + + + align:start position:0% +squared over Omega N squared so it +becomes that that's simple and because I + + align:start position:0% +becomes that that's simple and because I + + + align:start position:0% +becomes that that's simple and because I +want to work with number this is ratio + + align:start position:0% +want to work with number this is ratio + + + align:start position:0% +want to work with number this is ratio +bigger than 1 I don't want this to be + + align:start position:0% +bigger than 1 I don't want this to be + + + align:start position:0% +bigger than 1 I don't want this to be +negative and I want to mess with keep + + align:start position:0% +negative and I want to mess with keep + + + align:start position:0% +negative and I want to mess with keep +carrying along absolute value signs this + + align:start position:0% +carrying along absolute value signs this + + + align:start position:0% +carrying along absolute value signs this +is the same thing as 1 over Omega + + align:start position:0% +is the same thing as 1 over Omega + + + align:start position:0% +is the same thing as 1 over Omega +squared over Omega N squared minus 1 + + align:start position:0% +squared over Omega N squared minus 1 + + + align:start position:0% +squared over Omega N squared minus 1 +I just reverse this because I know we're + + align:start position:0% +I just reverse this because I know we're + + + align:start position:0% +I just reverse this because I know we're +going to deal only with ones greater + + align:start position:0% +going to deal only with ones greater + + + align:start position:0% +going to deal only with ones greater +than 1 here and I need this to be equal + + align:start position:0% +than 1 here and I need this to be equal + + + align:start position:0% +than 1 here and I need this to be equal +to 0.1 and that's just algebra you can + + align:start position:0% +to 0.1 and that's just algebra you can + + + align:start position:0% +to 0.1 and that's just algebra you can +solve that this implies that Omega over + + align:start position:0% +solve that this implies that Omega over + + + align:start position:0% +solve that this implies that Omega over +Omega N equals root 11 I recall + + align:start position:0% + + + + align:start position:0% + +and that is 3.31 + + align:start position:0% +and that is 3.31 + + + align:start position:0% +and that is 3.31 +so this is saying on that curve if you + + align:start position:0% +so this is saying on that curve if you + + + align:start position:0% +so this is saying on that curve if you +go out to Omega over Omega N equals + + align:start position:0% +go out to Omega over Omega N equals + + + align:start position:0% +go out to Omega over Omega N equals +three point three one right about where + + align:start position:0% +three point three one right about where + + + align:start position:0% +three point three one right about where +that arrow is that the curve for zero + + align:start position:0% +that arrow is that the curve for zero + + + align:start position:0% +that arrow is that the curve for zero +damping drops down to zero point one and + + align:start position:0% +damping drops down to zero point one and + + + align:start position:0% +damping drops down to zero point one and +now if at that frequency so we need that + + align:start position:0% +now if at that frequency so we need that + + + align:start position:0% +now if at that frequency so we need that +means we have to design the spring + + align:start position:0% +means we have to design the spring + + + align:start position:0% +means we have to design the spring +support such that Omega n is equal to + + align:start position:0% +support such that Omega n is equal to + + + align:start position:0% +support such that Omega n is equal to +Omega over three point three one but + + align:start position:0% +Omega over three point three one but + + + align:start position:0% +Omega over three point three one but +Omega where do we start + + align:start position:0% +Omega where do we start + + + align:start position:0% +Omega where do we start +so F equals 20 Hertz Omega equals two pi + + align:start position:0% +so F equals 20 Hertz Omega equals two pi + + + align:start position:0% +so F equals 20 Hertz Omega equals two pi +F do I have that number here no but so + + align:start position:0% +F do I have that number here no but so + + + align:start position:0% +F do I have that number here no but so +this tells me that I need a natural + + align:start position:0% +this tells me that I need a natural + + + align:start position:0% +this tells me that I need a natural +frequency that is omega over three point + + align:start position:0% +frequency that is omega over three point + + + align:start position:0% +frequency that is omega over three point +three one or I need an F and that is F + + align:start position:0% +three one or I need an F and that is F + + + align:start position:0% +three one or I need an F and that is F +over three point three one is twenty + + align:start position:0% +over three point three one is twenty + + + align:start position:0% +over three point three one is twenty +Hertz + + align:start position:0% +Hertz + + + align:start position:0% +Hertz +over three point three one and that + + align:start position:0% +over three point three one and that + + + align:start position:0% +over three point three one and that +number I do have six point zero four + + align:start position:0% +number I do have six point zero four + + + align:start position:0% +number I do have six point zero four +Hertz so I need a support whose natural + + align:start position:0% +Hertz so I need a support whose natural + + + align:start position:0% +Hertz so I need a support whose natural +frequency is twenty Hertz divided by + + align:start position:0% +frequency is twenty Hertz divided by + + + align:start position:0% +frequency is twenty Hertz divided by +this ratio by three point three one and + + align:start position:0% +this ratio by three point three one and + + + align:start position:0% +this ratio by three point three one and +that's I need a support is natural + + align:start position:0% +that's I need a support is natural + + + align:start position:0% +that's I need a support is natural +frequency is six point zero four Hertz + + align:start position:0% + + + + align:start position:0% + +and that's how you go about designing a + + align:start position:0% +and that's how you go about designing a + + + align:start position:0% +and that's how you go about designing a +flexible base to isolate something from + + align:start position:0% +flexible base to isolate something from + + + align:start position:0% +flexible base to isolate something from +vibration of whatever it's sitting on + + align:start position:0% +vibration of whatever it's sitting on + + + align:start position:0% +vibration of whatever it's sitting on +alright let's so my F here twenty Hertz + + align:start position:0% +alright let's so my F here twenty Hertz + + + align:start position:0% +alright let's so my F here twenty Hertz +well my F n needs to be six point zero + + align:start position:0% +well my F n needs to be six point zero + + + align:start position:0% +well my F n needs to be six point zero +four Hertz that implies x to pi + + align:start position:0% +four Hertz that implies x to pi + + + align:start position:0% +four Hertz that implies x to pi +I'm looking for 37 point ninety six + + align:start position:0% +I'm looking for 37 point ninety six + + + align:start position:0% +I'm looking for 37 point ninety six +radians per second and that's equal to + + align:start position:0% +radians per second and that's equal to + + + align:start position:0% +radians per second and that's equal to +square root of K over m so now what's + + align:start position:0% +square root of K over m so now what's + + + align:start position:0% +square root of K over m so now what's +the M well it's whatever the mass of the + + align:start position:0% +the M well it's whatever the mass of the + + + align:start position:0% +the M well it's whatever the mass of the +microscope plus its base + + align:start position:0% +microscope plus its base + + + align:start position:0% +microscope plus its base +whatever your whatever is being + + align:start position:0% +whatever your whatever is being + + + align:start position:0% +whatever your whatever is being +supported by the springs the will have + + align:start position:0% +supported by the springs the will have + + + align:start position:0% +supported by the springs the will have +that mass you have to choose the K so + + align:start position:0% +that mass you have to choose the K so + + + align:start position:0% +that mass you have to choose the K so +let's say let say the M total for this + + align:start position:0% +let's say let say the M total for this + + + align:start position:0% +let's say let say the M total for this +system is 20 kilograms solve this + + align:start position:0% +system is 20 kilograms solve this + + + align:start position:0% +system is 20 kilograms solve this +equation for K and that implies that K + + align:start position:0% +equation for K and that implies that K + + + align:start position:0% +equation for K and that implies that K +is twenty eight thousand eight hundred + + align:start position:0% +is twenty eight thousand eight hundred + + + align:start position:0% +is twenty eight thousand eight hundred +and twenty-seven Newton's per meter so + + align:start position:0% +and twenty-seven Newton's per meter so + + + align:start position:0% +and twenty-seven Newton's per meter so +if we were designed this system and it + + align:start position:0% +if we were designed this system and it + + + align:start position:0% +if we were designed this system and it +really mounts up to in the case of this + + align:start position:0% +really mounts up to in the case of this + + + align:start position:0% +really mounts up to in the case of this +let's see beams is this stiffness of a + + align:start position:0% +let's see beams is this stiffness of a + + + align:start position:0% +let's see beams is this stiffness of a +beam wow that's a good we'll do this we + + align:start position:0% +beam wow that's a good we'll do this we + + + align:start position:0% +beam wow that's a good we'll do this we +have a little we have a cantilever here + + align:start position:0% +have a little we have a cantilever here + + + align:start position:0% +have a little we have a cantilever here +and we've got a mass on the end but you + + align:start position:0% +and we've got a mass on the end but you + + + align:start position:0% +and we've got a mass on the end but you +most of you have been taken to double O + + align:start position:0% +most of you have been taken to double O + + + align:start position:0% +most of you have been taken to double O +one if you put a force out here P what's + + align:start position:0% +one if you put a force out here P what's + + + align:start position:0% +one if you put a force out here P what's +the deflection at the end of a + + align:start position:0% +the deflection at the end of a + + + align:start position:0% +the deflection at the end of a +cantilever okay so Delta PL cubed over + + align:start position:0% +cantilever okay so Delta PL cubed over + + + align:start position:0% +cantilever okay so Delta PL cubed over +three e I and the load this force is + + align:start position:0% +three e I and the load this force is + + + align:start position:0% +three e I and the load this force is +equal to some K equivalent times Delta + + align:start position:0% +equal to some K equivalent times Delta + + + align:start position:0% +equal to some K equivalent times Delta +right this is just a spring and K times + + align:start position:0% +right this is just a spring and K times + + + align:start position:0% +right this is just a spring and K times +the displacement is the force it takes + + align:start position:0% +the displacement is the force it takes + + + align:start position:0% +the displacement is the force it takes +to do it + + align:start position:0% +to do it + + + align:start position:0% +to do it +so P is my force the Pring constant is + + align:start position:0% +so P is my force the Pring constant is + + + align:start position:0% +so P is my force the Pring constant is +somehow associated with the rest of this + + align:start position:0% +somehow associated with the rest of this + + + align:start position:0% +somehow associated with the rest of this +stuff so if I solve for P over Delta I + + align:start position:0% +stuff so if I solve for P over Delta I + + + align:start position:0% +stuff so if I solve for P over Delta I +get three + + align:start position:0% +get three + + + align:start position:0% +get three +I over L cubed okay so if if my if I'm + + align:start position:0% +I over L cubed okay so if if my if I'm + + + align:start position:0% +I over L cubed okay so if if my if I'm +running right at the natural frequency + + align:start position:0% +running right at the natural frequency + + + align:start position:0% +running right at the natural frequency +here and I want to reduce this to a + + align:start position:0% +here and I want to reduce this to a + + + align:start position:0% +here and I want to reduce this to a +tenth of its motion I need to change the + + align:start position:0% +tenth of its motion I need to change the + + + align:start position:0% +tenth of its motion I need to change the +spring constant of the cantilever by + + align:start position:0% +spring constant of the cantilever by + + + align:start position:0% +spring constant of the cantilever by +factor of what I need to change the + + align:start position:0% +factor of what I need to change the + + + align:start position:0% +factor of what I need to change the +natural frequency by a factor of three + + align:start position:0% +natural frequency by a factor of three + + + align:start position:0% +natural frequency by a factor of three +point three one so my K equivalent here + + align:start position:0% +point three one so my K equivalent here + + + align:start position:0% +point three one so my K equivalent here +is 3e I over L cubed and that's what + + align:start position:0% +is 3e I over L cubed and that's what + + + align:start position:0% +is 3e I over L cubed and that's what +would go into this equation but I know + + align:start position:0% +would go into this equation but I know + + + align:start position:0% +would go into this equation but I know +that I have a I have a natural frequency + + align:start position:0% +that I have a I have a natural frequency + + + align:start position:0% +that I have a I have a natural frequency +right now I want it to go down by a + + align:start position:0% +right now I want it to go down by a + + + align:start position:0% +right now I want it to go down by a +factor of three point three one so that + + align:start position:0% +factor of three point three one so that + + + align:start position:0% +factor of three point three one so that +means I need to decrease K by the such + + align:start position:0% +means I need to decrease K by the such + + + align:start position:0% +means I need to decrease K by the such +that the square root of K goes down by + + align:start position:0% +that the square root of K goes down by + + + align:start position:0% +that the square root of K goes down by +the factor three point three one so how + + align:start position:0% +the factor three point three one so how + + + align:start position:0% +the factor three point three one so how +do how much do I have to change the + + align:start position:0% +do how much do I have to change the + + + align:start position:0% +do how much do I have to change the +length probably something like the + + align:start position:0% +length probably something like the + + + align:start position:0% +length probably something like the +square root of three point three one + + align:start position:0% + + + + align:start position:0% + +roughly two if I double the length of + + align:start position:0% +roughly two if I double the length of + + + align:start position:0% +roughly two if I double the length of +this thing you think it's going to work + + align:start position:0% +this thing you think it's going to work + + + align:start position:0% +this thing you think it's going to work +I double the length of this thing and + + align:start position:0% +I double the length of this thing and + + + align:start position:0% +I double the length of this thing and +turn it back on we shouldn't see much + + align:start position:0% +turn it back on we shouldn't see much + + + align:start position:0% +turn it back on we shouldn't see much +motion out of this that's moving a lot + + align:start position:0% +motion out of this that's moving a lot + + + align:start position:0% +motion out of this that's moving a lot +Oh a tiny tiny bit it works so that's + + align:start position:0% +Oh a tiny tiny bit it works so that's + + + align:start position:0% +Oh a tiny tiny bit it works so that's +one step of vibration isolation now I'm + + align:start position:0% +one step of vibration isolation now I'm + + + align:start position:0% +one step of vibration isolation now I'm +going to show you a vibration engineer + + align:start position:0% +going to show you a vibration engineer + + + align:start position:0% +going to show you a vibration engineer +trick which is very handy thing to know + + align:start position:0% + + + + align:start position:0% + +where's my strong magnet here so I've + + align:start position:0% +where's my strong magnet here so I've + + + align:start position:0% +where's my strong magnet here so I've +got another beam just like this one and + + align:start position:0% +got another beam just like this one and + + + align:start position:0% +got another beam just like this one and +a pretty pretty massive magnet on it so + + align:start position:0% +a pretty pretty massive magnet on it so + + + align:start position:0% +a pretty pretty massive magnet on it so +it makes another cantilever beam just + + align:start position:0% +it makes another cantilever beam just + + + align:start position:0% +it makes another cantilever beam just +like I got over there okay so I claim + + align:start position:0% +like I got over there okay so I claim + + + align:start position:0% +like I got over there okay so I claim +that with just a ruler if I clamp this + + align:start position:0% +that with just a ruler if I clamp this + + + align:start position:0% +that with just a ruler if I clamp this +down and at some length I claim with + + align:start position:0% +down and at some length I claim with + + + align:start position:0% +down and at some length I claim with +just a ruler I can predict the natural + + align:start position:0% +just a ruler I can predict the natural + + + align:start position:0% +just a ruler I can predict the natural +frequency of that take a couple minutes + + align:start position:0% +frequency of that take a couple minutes + + + align:start position:0% +frequency of that take a couple minutes +and see if you figure out how to do it + + align:start position:0% +and see if you figure out how to do it + + + align:start position:0% +and see if you figure out how to do it +think about that just a ruler + + align:start position:0% +think about that just a ruler + + + align:start position:0% +think about that just a ruler +measurements that I can make I don't + + align:start position:0% +measurements that I can make I don't + + + align:start position:0% +measurements that I can make I don't +just I don't know how long it don't know + + align:start position:0% +just I don't know how long it don't know + + + align:start position:0% +just I don't know how long it don't know +how long it actually is I don't know I + + align:start position:0% +how long it actually is I don't know I + + + align:start position:0% +how long it actually is I don't know I +think it is it's I know it's steel but + + align:start position:0% +think it is it's I know it's steel but + + + align:start position:0% +think it is it's I know it's steel but +you just don't have enough information + + align:start position:0% +you just don't have enough information + + + align:start position:0% +you just don't have enough information +to compute L q 3i over L cubed but with + + align:start position:0% +to compute L q 3i over L cubed but with + + + align:start position:0% +to compute L q 3i over L cubed but with +simply with a ruler I'm going to be able + + align:start position:0% +simply with a ruler I'm going to be able + + + align:start position:0% +simply with a ruler I'm going to be able +to do this talk about it think about + + align:start position:0% +to do this talk about it think about + + + align:start position:0% +to do this talk about it think about +that well I set up D set up the + + align:start position:0% +that well I set up D set up the + + + align:start position:0% +that well I set up D set up the +experiment + + align:start position:0% + + + + align:start position:0% + +okay who's got it figured out we want to + + align:start position:0% +okay who's got it figured out we want to + + + align:start position:0% +okay who's got it figured out we want to +take a shot at this + + align:start position:0% + + + + align:start position:0% + +so there's my beam I put the weight on + + align:start position:0% +so there's my beam I put the weight on + + + align:start position:0% +so there's my beam I put the weight on +it what does the beam do statically + + align:start position:0% +it what does the beam do statically + + + align:start position:0% +it what does the beam do statically +bends a little right K X static equals + + align:start position:0% + + + + align:start position:0% + +mg right has two so X static is when I + + align:start position:0% +mg right has two so X static is when I + + + align:start position:0% +mg right has two so X static is when I +call it Delta here so K Delta equals mg + + align:start position:0% +call it Delta here so K Delta equals mg + + + align:start position:0% +call it Delta here so K Delta equals mg +K equals mg over Delta natural frequency + + align:start position:0% +K equals mg over Delta natural frequency + + + align:start position:0% +K equals mg over Delta natural frequency +equals square root K over m + + align:start position:0% + + + + align:start position:0% + +credibly simple huh so what's the + + align:start position:0% +credibly simple huh so what's the + + + align:start position:0% +credibly simple huh so what's the +experiment that I would what what + + align:start position:0% +experiment that I would what what + + + align:start position:0% +experiment that I would what what +measurement would I make Delta right put + + align:start position:0% +measurement would I make Delta right put + + + align:start position:0% +measurement would I make Delta right put +my ruler up there I measure its static + + align:start position:0% +my ruler up there I measure its static + + + align:start position:0% +my ruler up there I measure its static +position like that and I put my mass on + + align:start position:0% +position like that and I put my mass on + + + align:start position:0% +position like that and I put my mass on +it and I measure the static position + + align:start position:0% +it and I measure the static position + + + align:start position:0% +it and I measure the static position +again I measure the Delta and I get a + + align:start position:0% +again I measure the Delta and I get a + + + align:start position:0% +again I measure the Delta and I get a +prediction and I did this in my in my + + align:start position:0% +prediction and I did this in my in my + + + align:start position:0% +prediction and I did this in my in my +office + + align:start position:0% + + + + align:start position:0% + +and the Delta that I measured so the + + align:start position:0% +and the Delta that I measured so the + + + align:start position:0% +and the Delta that I measured so the +length is actually set it at a + + align:start position:0% +length is actually set it at a + + + align:start position:0% +length is actually set it at a +particular length it was 18 centimeters + + align:start position:0% +particular length it was 18 centimeters + + + align:start position:0% +particular length it was 18 centimeters +Delta measured thick 0.5 centimeters or + + align:start position:0% +Delta measured thick 0.5 centimeters or + + + align:start position:0% +Delta measured thick 0.5 centimeters or +0.0 0.0 5 meters and if you compute + + align:start position:0% +0.0 0.0 5 meters and if you compute + + + align:start position:0% +0.0 0.0 5 meters and if you compute +Omega n then equals the square root of + + align:start position:0% +Omega n then equals the square root of + + + align:start position:0% +Omega n then equals the square root of +nine point eight one over 0.05 + + align:start position:0% + + + + align:start position:0% + +and I want this in Hertz I am divided by + + align:start position:0% +and I want this in Hertz I am divided by + + + align:start position:0% +and I want this in Hertz I am divided by +2pi this comes out as 7.0 five Hertz and + + align:start position:0% +2pi this comes out as 7.0 five Hertz and + + + align:start position:0% +2pi this comes out as 7.0 five Hertz and +FN measured was six point five seven + + align:start position:0% + + + + align:start position:0% + +pretty good but not perfect + + align:start position:0% + + + + align:start position:0% + +what and it's because it made an + + align:start position:0% +what and it's because it made an + + + align:start position:0% +what and it's because it made an +approximation I glossed over pretty + + align:start position:0% +approximation I glossed over pretty + + + align:start position:0% +approximation I glossed over pretty +quickly what has been left out of this + + align:start position:0% +quickly what has been left out of this + + + align:start position:0% +quickly what has been left out of this +system that would cause the measured + + align:start position:0% +system that would cause the measured + + + align:start position:0% +system that would cause the measured +natural frequency to be lower than the + + align:start position:0% +natural frequency to be lower than the + + + align:start position:0% +natural frequency to be lower than the +predicted what's been ignored yes + + align:start position:0% +predicted what's been ignored yes + + + align:start position:0% +predicted what's been ignored yes +damping ah maybe how much damping do we + + align:start position:0% +damping ah maybe how much damping do we + + + align:start position:0% +damping ah maybe how much damping do we +have in this system probably at least + + align:start position:0% +have in this system probably at least + + + align:start position:0% +have in this system probably at least +ten cycles the decay halfway right + + align:start position:0% +ten cycles the decay halfway right + + + align:start position:0% +ten cycles the decay halfway right +certainly less than one percent so + + align:start position:0% +certainly less than one percent so + + + align:start position:0% +certainly less than one percent so +natural is the damped natural frequency + + align:start position:0% +natural is the damped natural frequency + + + align:start position:0% +natural is the damped natural frequency +is equal to the natural frequency the + + align:start position:0% +is equal to the natural frequency the + + + align:start position:0% +is equal to the natural frequency the +square root of 1 minus Zeta squared so + + align:start position:0% +square root of 1 minus Zeta squared so + + + align:start position:0% +square root of 1 minus Zeta squared so +this is something like way less than + + align:start position:0% +this is something like way less than + + + align:start position:0% +this is something like way less than +half a percent difference so that + + align:start position:0% +half a percent difference so that + + + align:start position:0% +half a percent difference so that +wouldn't account for it that's + + align:start position:0% +wouldn't account for it that's + + + align:start position:0% +wouldn't account for it that's +considerably more than half a percent so + + align:start position:0% +considerably more than half a percent so + + + align:start position:0% +considerably more than half a percent so +damping couldn't do it yeah ah the mass + + align:start position:0% +damping couldn't do it yeah ah the mass + + + align:start position:0% +damping couldn't do it yeah ah the mass +of the bar does this flexure have mass + + align:start position:0% +of the bar does this flexure have mass + + + align:start position:0% +of the bar does this flexure have mass +yeah it's probably the order of you've + + align:start position:0% +yeah it's probably the order of you've + + + align:start position:0% +yeah it's probably the order of you've +stack them all up and compared to that + + align:start position:0% +stack them all up and compared to that + + + align:start position:0% +stack them all up and compared to that +it's probably you I might even be as + + align:start position:0% +it's probably you I might even be as + + + align:start position:0% +it's probably you I might even be as +much as half the mass at the end and as + + align:start position:0% +much as half the mass at the end and as + + + align:start position:0% +much as half the mass at the end and as +it vibrates back and forth does it have + + align:start position:0% +it vibrates back and forth does it have + + + align:start position:0% +it vibrates back and forth does it have +kinetic energy yeah we've ignored the + + align:start position:0% +kinetic energy yeah we've ignored the + + + align:start position:0% +kinetic energy yeah we've ignored the +kinetic energy of the mass and in fact + + align:start position:0% +kinetic energy of the mass and in fact + + + align:start position:0% +kinetic energy of the mass and in fact +that's the principle error here we've + + align:start position:0% +that's the principle error here we've + + + align:start position:0% +that's the principle error here we've +left out the mass it's actually pretty + + align:start position:0% +left out the mass it's actually pretty + + + align:start position:0% +left out the mass it's actually pretty +simple way to account using energy just + + align:start position:0% +simple way to account using energy just + + + align:start position:0% +simple way to account using energy just +thinking in launch terms you can account + + align:start position:0% +thinking in launch terms you can account + + + align:start position:0% +thinking in launch terms you can account +for the energy of the mass in this + + align:start position:0% +for the energy of the mass in this + + + align:start position:0% +for the energy of the mass in this +single degree freedom system and get a + + align:start position:0% +single degree freedom system and get a + + + align:start position:0% +single degree freedom system and get a +very accurate position of a prediction + + align:start position:0% +very accurate position of a prediction + + + align:start position:0% +very accurate position of a prediction +we won't do that today but it will do + + align:start position:0% +we won't do that today but it will do + + + align:start position:0% +we won't do that today but it will do +that before the terms out + + align:start position:0% + + + + align:start position:0% + +okay this applies to any simple + + align:start position:0% +okay this applies to any simple + + + align:start position:0% +okay this applies to any simple +mass-spring system in the presence of + + align:start position:0% +mass-spring system in the presence of + + + align:start position:0% +mass-spring system in the presence of +gravity so here's a mass and actually + + align:start position:0% +gravity so here's a mass and actually + + + align:start position:0% +gravity so here's a mass and actually +I'm we're doing the problem today where + + align:start position:0% +I'm we're doing the problem today where + + + align:start position:0% +I'm we're doing the problem today where +I'm moving the base here so here's its + + align:start position:0% +I'm moving the base here so here's its + + + align:start position:0% +I'm moving the base here so here's its +base so hisses this is the table moving + + align:start position:0% +base so hisses this is the table moving + + + align:start position:0% +base so hisses this is the table moving +and if I do this it clearly makes that + + align:start position:0% +and if I do this it clearly makes that + + + align:start position:0% +and if I do this it clearly makes that +move if I do this really fast it doesn't + + align:start position:0% +move if I do this really fast it doesn't + + + align:start position:0% +move if I do this really fast it doesn't +know very much if I do a close-up + + align:start position:0% +know very much if I do a close-up + + + align:start position:0% +know very much if I do a close-up +natural frequency it moves a lot if I + + align:start position:0% +natural frequency it moves a lot if I + + + align:start position:0% +natural frequency it moves a lot if I +move it very slowly as I go up one unit + + align:start position:0% +move it very slowly as I go up one unit + + + align:start position:0% +move it very slowly as I go up one unit +this it follows me exactly that's why + + align:start position:0% +this it follows me exactly that's why + + + align:start position:0% +this it follows me exactly that's why +that plot goes to one at very very low + + align:start position:0% +that plot goes to one at very very low + + + align:start position:0% +that plot goes to one at very very low +frequency the support and the mass move + + align:start position:0% +frequency the support and the mass move + + + align:start position:0% +frequency the support and the mass move +exactly together at high very high + + align:start position:0% +exactly together at high very high + + + align:start position:0% +exactly together at high very high +frequency if I can stop the transient + + align:start position:0% +frequency if I can stop the transient + + + align:start position:0% +frequency if I can stop the transient +can't do it very well the mass doesn't + + align:start position:0% +can't do it very well the mass doesn't + + + align:start position:0% +can't do it very well the mass doesn't +move much the basement lives a lot and + + align:start position:0% +move much the basement lives a lot and + + + align:start position:0% +move much the basement lives a lot and +at resonance it goes nuts + + align:start position:0% +at resonance it goes nuts + + + align:start position:0% +at resonance it goes nuts +okay the unstretched length of this + + align:start position:0% +okay the unstretched length of this + + + align:start position:0% +okay the unstretched length of this +spring is about seven inches the square + + align:start position:0% +spring is about seven inches the square + + + align:start position:0% +spring is about seven inches the square +root of G over Delta I ought to be able + + align:start position:0% +root of G over Delta I ought to be able + + + align:start position:0% +root of G over Delta I ought to be able +to predict this so I did a quick + + align:start position:0% +to predict this so I did a quick + + + align:start position:0% +to predict this so I did a quick +calculation on that and I came I had we + + align:start position:0% +calculation on that and I came I had we + + + align:start position:0% +calculation on that and I came I had we +did it it was like one percent error I + + align:start position:0% +did it it was like one percent error I + + + align:start position:0% +did it it was like one percent error I +measured it it's seven point three six + + align:start position:0% +measured it it's seven point three six + + + align:start position:0% +measured it it's seven point three six +radians a second and I'm predicted at + + align:start position:0% +radians a second and I'm predicted at + + + align:start position:0% +radians a second and I'm predicted at +four point seven four seven point four + + align:start position:0% +four point seven four seven point four + + + align:start position:0% +four point seven four seven point four +three measured seven point three six + + align:start position:0% +three measured seven point three six + + + align:start position:0% +three measured seven point three six +same kind of thing ignoring the mass of + + align:start position:0% +same kind of thing ignoring the mass of + + + align:start position:0% +same kind of thing ignoring the mass of +the spring a little bit so G over Delta + + align:start position:0% +the spring a little bit so G over Delta + + + align:start position:0% +the spring a little bit so G over Delta +is a great little thing to remember okay + + align:start position:0% + + + + align:start position:0% + +so we have done all but one everything + + align:start position:0% +so we have done all but one everything + + + align:start position:0% +so we have done all but one everything +we started out with today we said + + align:start position:0% +we started out with today we said + + + align:start position:0% +we started out with today we said +there's three ways to fix this and came + + align:start position:0% +there's three ways to fix this and came + + + align:start position:0% +there's three ways to fix this and came +up with the fourth way so in this case + + align:start position:0% +up with the fourth way so in this case + + + align:start position:0% +up with the fourth way so in this case +soften the spring support a lot so that + + align:start position:0% +soften the spring support a lot so that + + + align:start position:0% +soften the spring support a lot so that +the natural frequency is way less than + + align:start position:0% +the natural frequency is way less than + + + align:start position:0% +the natural frequency is way less than +the excitation we said we could what + + align:start position:0% +the excitation we said we could what + + + align:start position:0% +the excitation we said we could what +about spring supporting softening + + align:start position:0% +about spring supporting softening + + + align:start position:0% +about spring supporting softening +flexibly mounting this source so that it + + align:start position:0% +flexibly mounting this source so that it + + + align:start position:0% +flexibly mounting this source so that it +doesn't put vibration to the table + + align:start position:0% +doesn't put vibration to the table + + + align:start position:0% +doesn't put vibration to the table +that's the piece we haven't addressed so + + align:start position:0% +that's the piece we haven't addressed so + + + align:start position:0% +that's the piece we haven't addressed so +let's look into that problem now + + align:start position:0% + + + + align:start position:0% + +so here's our source some rotating mass + + align:start position:0% +so here's our source some rotating mass + + + align:start position:0% +so here's our source some rotating mass +eccentricity causing an excitation so + + align:start position:0% +eccentricity causing an excitation so + + + align:start position:0% +eccentricity causing an excitation so +this has a force F naught e to the I + + align:start position:0% +this has a force F naught e to the I + + + align:start position:0% +this has a force F naught e to the I +Omega T which is coming from the + + align:start position:0% +Omega T which is coming from the + + + align:start position:0% +Omega T which is coming from the +rotating mass and it applies to the + + align:start position:0% +rotating mass and it applies to the + + + align:start position:0% +rotating mass and it applies to the +floor through the dashpot in the springs + + align:start position:0% +floor through the dashpot in the springs + + + align:start position:0% +floor through the dashpot in the springs +some ft I'll call it F transmitted to + + align:start position:0% +some ft I'll call it F transmitted to + + + align:start position:0% +some ft I'll call it F transmitted to +the floor e to the I Omega T and I want + + align:start position:0% +the floor e to the I Omega T and I want + + + align:start position:0% +the floor e to the I Omega T and I want +to know I need the H force transmitted + + align:start position:0% +to know I need the H force transmitted + + + align:start position:0% +to know I need the H force transmitted +per unit force input transfer function + + align:start position:0% +per unit force input transfer function + + + align:start position:0% +per unit force input transfer function +that's what I'm looking for + + align:start position:0% + + + + align:start position:0% + +so now Freebody diagram now we're going + + align:start position:0% +so now Freebody diagram now we're going + + + align:start position:0% +so now Freebody diagram now we're going +to make an assumption we're going to + + align:start position:0% +to make an assumption we're going to + + + align:start position:0% +to make an assumption we're going to +assume that the motion of the floor + + align:start position:0% +assume that the motion of the floor + + + align:start position:0% +assume that the motion of the floor +which we'll call Y of T assume that Y is + + align:start position:0% +which we'll call Y of T assume that Y is + + + align:start position:0% +which we'll call Y of T assume that Y is +much much less than X it's generally + + align:start position:0% +much much less than X it's generally + + + align:start position:0% +much much less than X it's generally +true whatever is doing is shaking like + + align:start position:0% +true whatever is doing is shaking like + + + align:start position:0% +true whatever is doing is shaking like +crazy before the tables not moving much + + align:start position:0% +crazy before the tables not moving much + + + align:start position:0% +crazy before the tables not moving much +underneath it so I would assume for the + + align:start position:0% +underneath it so I would assume for the + + + align:start position:0% +underneath it so I would assume for the +purposes of calculating forces that this + + align:start position:0% +purposes of calculating forces that this + + + align:start position:0% +purposes of calculating forces that this +is zero so for the motion X what is the + + align:start position:0% +is zero so for the motion X what is the + + + align:start position:0% +is zero so for the motion X what is the +force applied to the floor so f of T if + + align:start position:0% +force applied to the floor so f of T if + + + align:start position:0% +force applied to the floor so f of T if +you have a positive displacement X the + + align:start position:0% +you have a positive displacement X the + + + align:start position:0% +you have a positive displacement X the +force is KX you have a positive velocity + + align:start position:0% +force is KX you have a positive velocity + + + align:start position:0% +force is KX you have a positive velocity +X the force pulling up on the floor + + align:start position:0% +X the force pulling up on the floor + + + align:start position:0% +X the force pulling up on the floor +through the dashpot is CX dot so the + + align:start position:0% +through the dashpot is CX dot so the + + + align:start position:0% +through the dashpot is CX dot so the +other way of saying that is here's our + + align:start position:0% +other way of saying that is here's our + + + align:start position:0% +other way of saying that is here's our +free body diagram here's our F naught e + + align:start position:0% +free body diagram here's our F naught e + + + align:start position:0% +free body diagram here's our F naught e +to the I Omega T pulling up it responds + + align:start position:0% +to the I Omega T pulling up it responds + + + align:start position:0% +to the I Omega T pulling up it responds +at some X and the resulting forces + + align:start position:0% +at some X and the resulting forces + + + align:start position:0% +at some X and the resulting forces +through the spring of the dashpot we + + align:start position:0% +through the spring of the dashpot we + + + align:start position:0% +through the spring of the dashpot we +know are KX and CX dot opposing the + + align:start position:0% +know are KX and CX dot opposing the + + + align:start position:0% +know are KX and CX dot opposing the +motion acts well by third law if these + + align:start position:0% +motion acts well by third law if these + + + align:start position:0% +motion acts well by third law if these +are the forces on the spring and the + + align:start position:0% +are the forces on the spring and the + + + align:start position:0% +are the forces on the spring and the +dashpot then down here on the floor you + + align:start position:0% +dashpot then down here on the floor you + + + align:start position:0% +dashpot then down here on the floor you +better have some equal and opposite + + align:start position:0% +better have some equal and opposite + + + align:start position:0% +better have some equal and opposite +forces KX and CX dot so motion this + + align:start position:0% +forces KX and CX dot so motion this + + + align:start position:0% +forces KX and CX dot so motion this +force produces a motion X the motion X + + align:start position:0% +force produces a motion X the motion X + + + align:start position:0% +force produces a motion X the motion X +produces forces in the mass in the + + align:start position:0% +produces forces in the mass in the + + + align:start position:0% +produces forces in the mass in the +spring which make this the floor the + + align:start position:0% +spring which make this the floor the + + + align:start position:0% +spring which make this the floor the +force on the floor the spring force and + + align:start position:0% +force on the floor the spring force and + + + align:start position:0% +force on the floor the spring force and +the dashpot force okay + + align:start position:0% + + + + align:start position:0% + +so this ft is right here + + align:start position:0% + + + + align:start position:0% + +that's all that is positive and I'm + + align:start position:0% +that's all that is positive and I'm + + + align:start position:0% +that's all that is positive and I'm +going to assume a solution we know to + + align:start position:0% +going to assume a solution we know to + + + align:start position:0% +going to assume a solution we know to +work for X which is X e to the I Omega + + align:start position:0% +work for X which is X e to the I Omega + + + align:start position:0% +work for X which is X e to the I Omega +key we plugged it in before so if I plug + + align:start position:0% +key we plugged it in before so if I plug + + + align:start position:0% +key we plugged it in before so if I plug +that in here I get a ke plus I Omega C X + + align:start position:0% +that in here I get a ke plus I Omega C X + + + align:start position:0% +that in here I get a ke plus I Omega C X +e to the I Omega T so I can just express + + align:start position:0% +e to the I Omega T so I can just express + + + align:start position:0% +e to the I Omega T so I can just express +my force on the floor in terms of the + + align:start position:0% +my force on the floor in terms of the + + + align:start position:0% +my force on the floor in terms of the +motion X + + align:start position:0% + + + + align:start position:0% + +and I'm looking for a transfer function + + align:start position:0% +and I'm looking for a transfer function + + + align:start position:0% +and I'm looking for a transfer function +for force transmitted over force in but + + align:start position:0% +for force transmitted over force in but + + + align:start position:0% +for force transmitted over force in but +force transmitted is my ka plus I Omega + + align:start position:0% +force transmitted is my ka plus I Omega + + + align:start position:0% +force transmitted is my ka plus I Omega +C X e to the I Omega T and the force in + + align:start position:0% +C X e to the I Omega T and the force in + + + align:start position:0% +C X e to the I Omega T and the force in +is F naught e to the I Omega T cancel + + align:start position:0% +is F naught e to the I Omega T cancel + + + align:start position:0% +is F naught e to the I Omega T cancel +out the time dependent part and it says + + align:start position:0% +out the time dependent part and it says + + + align:start position:0% +out the time dependent part and it says +the transmitted force over the input + + align:start position:0% +the transmitted force over the input + + + align:start position:0% +the transmitted force over the input +force is this little complex expression + + align:start position:0% +force is this little complex expression + + + align:start position:0% +force is this little complex expression +times the response x over F but we know + + align:start position:0% +times the response x over F but we know + + + align:start position:0% +times the response x over F but we know +what that is that's the transfer + + align:start position:0% +what that is that's the transfer + + + align:start position:0% +what that is that's the transfer +function HX F so this is K plus I Omega + + align:start position:0% +function HX F so this is K plus I Omega + + + align:start position:0% +function HX F so this is K plus I Omega +C times H X F of Omega so this gives us + + align:start position:0% +C times H X F of Omega so this gives us + + + align:start position:0% +C times H X F of Omega so this gives us +a slightly different transfer function + + align:start position:0% +a slightly different transfer function + + + align:start position:0% +a slightly different transfer function +and have I proved look at this + + align:start position:0% + + + + align:start position:0% + +before when we did x over Y we ended up + + align:start position:0% +before when we did x over Y we ended up + + + align:start position:0% +before when we did x over Y we ended up +with K plus I Omega C Y e to the I Omega + + align:start position:0% +with K plus I Omega C Y e to the I Omega + + + align:start position:0% +with K plus I Omega C Y e to the I Omega +T and we did when we did then X over Y + + align:start position:0% +T and we did when we did then X over Y + + + align:start position:0% +T and we did when we did then X over Y +we got the same same ratio as this + + align:start position:0% +we got the same same ratio as this + + + align:start position:0% +we got the same same ratio as this +exactly the same thing so I could write + + align:start position:0% +exactly the same thing so I could write + + + align:start position:0% +exactly the same thing so I could write +all this out but and let's say I'll do + + align:start position:0% +all this out but and let's say I'll do + + + align:start position:0% +all this out but and let's say I'll do +this H X over Y no I don't do that well + + align:start position:0% +this H X over Y no I don't do that well + + + align:start position:0% +this H X over Y no I don't do that well +it turns out what I'm going to tell you + + align:start position:0% +it turns out what I'm going to tell you + + + align:start position:0% +it turns out what I'm going to tell you +if you just work through this now you + + align:start position:0% +if you just work through this now you + + + align:start position:0% +if you just work through this now you +will find that H force transmitted over + + align:start position:0% +will find that H force transmitted over + + + align:start position:0% +will find that H force transmitted over +force in is exactly the same as H X over + + align:start position:0% +force in is exactly the same as H X over + + + align:start position:0% +force in is exactly the same as H X over +Y + + align:start position:0% + + + + align:start position:0% + +and that what we really care about is + + align:start position:0% +and that what we really care about is + + + align:start position:0% +and that what we really care about is +what the magnitude is so the magnitude + + align:start position:0% +what the magnitude is so the magnitude + + + align:start position:0% +what the magnitude is so the magnitude +of these two things are the same and in + + align:start position:0% +of these two things are the same and in + + + align:start position:0% +of these two things are the same and in +fact just work out to that same + + align:start position:0% +fact just work out to that same + + + align:start position:0% +fact just work out to that same +expression as before the 1 plus 2 Zeta + + align:start position:0% +expression as before the 1 plus 2 Zeta + + + align:start position:0% +expression as before the 1 plus 2 Zeta +Omega over Omega N squared square root + + align:start position:0% +Omega over Omega N squared square root + + + align:start position:0% +Omega over Omega N squared square root +all over the usual but denominator so + + align:start position:0% +all over the usual but denominator so + + + align:start position:0% +all over the usual but denominator so +conveniently for vibration isolation the + + align:start position:0% +conveniently for vibration isolation the + + + align:start position:0% +conveniently for vibration isolation the +two the solution to the two problems are + + align:start position:0% +two the solution to the two problems are + + + align:start position:0% +two the solution to the two problems are +exactly the same so if you have that one + + align:start position:0% +exactly the same so if you have that one + + + align:start position:0% +exactly the same so if you have that one +you have the transfer function XY that + + align:start position:0% +you have the transfer function XY that + + + align:start position:0% +you have the transfer function XY that +was projected on the screen a minute ago + + align:start position:0% +was projected on the screen a minute ago + + + align:start position:0% +was projected on the screen a minute ago +it is also the force transmitted to + + align:start position:0% +it is also the force transmitted to + + + align:start position:0% +it is also the force transmitted to +force in transfer function so you just + + align:start position:0% +force in transfer function so you just + + + align:start position:0% +force in transfer function so you just +have to get you have to remember one and + + align:start position:0% +have to get you have to remember one and + + + align:start position:0% +have to get you have to remember one and +if you will now want to we said let's + + align:start position:0% +if you will now want to we said let's + + + align:start position:0% +if you will now want to we said let's +say doubling the length of this just + + align:start position:0% +say doubling the length of this just + + + align:start position:0% +say doubling the length of this just +about accomplish the reducing the + + align:start position:0% +about accomplish the reducing the + + + align:start position:0% +about accomplish the reducing the +vibration of the microscope by this + + align:start position:0% +vibration of the microscope by this + + + align:start position:0% +vibration of the microscope by this +factor of ten so if I doubled the length + + align:start position:0% +factor of ten so if I doubled the length + + + align:start position:0% +factor of ten so if I doubled the length +of this one I would have come I would + + align:start position:0% +of this one I would have come I would + + + align:start position:0% +of this one I would have come I would +roughly do the same thing I would change + + align:start position:0% +roughly do the same thing I would change + + + align:start position:0% +roughly do the same thing I would change +that I would make the change in natural + + align:start position:0% +that I would make the change in natural + + + align:start position:0% +that I would make the change in natural +this thing is right on the natural + + align:start position:0% +this thing is right on the natural + + + align:start position:0% +this thing is right on the natural +frequency this beam that's why it shakes + + align:start position:0% +frequency this beam that's why it shakes + + + align:start position:0% +frequency this beam that's why it shakes +so much and it's Trent it's so it is + + align:start position:0% +so much and it's Trent it's so it is + + + align:start position:0% +so much and it's Trent it's so it is +this system it's shaking like crazy + + align:start position:0% +this system it's shaking like crazy + + + align:start position:0% +this system it's shaking like crazy +putting force into the table the table + + align:start position:0% +putting force into the table the table + + + align:start position:0% +putting force into the table the table +is vibrating putting causing the other + + align:start position:0% +is vibrating putting causing the other + + + align:start position:0% +is vibrating putting causing the other +one to move so now if I change this one + + align:start position:0% +one to move so now if I change this one + + + align:start position:0% +one to move so now if I change this one +and the same kind of idea maybe roughly + + align:start position:0% +and the same kind of idea maybe roughly + + + align:start position:0% +and the same kind of idea maybe roughly +double its length natural frequency + + align:start position:0% +double its length natural frequency + + + align:start position:0% +double its length natural frequency +diminishes by a factor of three or so + + align:start position:0% + + + + align:start position:0% + +the vibration of this ought to go way + + align:start position:0% +the vibration of this ought to go way + + + align:start position:0% +the vibration of this ought to go way +down + + align:start position:0% + + + + align:start position:0% + +and actually a little beam out here is + + align:start position:0% +and actually a little beam out here is + + + align:start position:0% +and actually a little beam out here is +picking up more than the other one so + + align:start position:0% +picking up more than the other one so + + + align:start position:0% +picking up more than the other one so +this is hardly moving at all in so by + + align:start position:0% +this is hardly moving at all in so by + + + align:start position:0% +this is hardly moving at all in so by +doing that we've essentially detuned it + + align:start position:0% +doing that we've essentially detuned it + + + align:start position:0% +doing that we've essentially detuned it +this is no longer running at the natural + + align:start position:0% +this is no longer running at the natural + + + align:start position:0% +this is no longer running at the natural +frequency of this base so it's no longer + + align:start position:0% +frequency of this base so it's no longer + + + align:start position:0% +frequency of this base so it's no longer +resonant you're way out on the curve to + + align:start position:0% +resonant you're way out on the curve to + + + align:start position:0% +resonant you're way out on the curve to +the right so the response of this isn't + + align:start position:0% +the right so the response of this isn't + + + align:start position:0% +the right so the response of this isn't +very much that means it doesn't transmit + + align:start position:0% +very much that means it doesn't transmit + + + align:start position:0% +very much that means it doesn't transmit +much force to the base maybe down by a + + align:start position:0% +much force to the base maybe down by a + + + align:start position:0% +much force to the base maybe down by a +factor of eight or ten it means the + + align:start position:0% +factor of eight or ten it means the + + + align:start position:0% +factor of eight or ten it means the +table vibration amplitude drops by that + + align:start position:0% +table vibration amplitude drops by that + + + align:start position:0% +table vibration amplitude drops by that +factor means that the base motion over + + align:start position:0% +factor means that the base motion over + + + align:start position:0% +factor means that the base motion over +here is now a factor of ten smaller than + + align:start position:0% +here is now a factor of ten smaller than + + + align:start position:0% +here is now a factor of ten smaller than +was to begin with so that we get a + + align:start position:0% +was to begin with so that we get a + + + align:start position:0% +was to begin with so that we get a +reduction of ten here and we get another + + align:start position:0% +reduction of ten here and we get another + + + align:start position:0% +reduction of ten here and we get another +reduction of ten here because we detuned + + align:start position:0% +reduction of ten here because we detuned + + + align:start position:0% +reduction of ten here because we detuned +it so you might get a factor of a + + align:start position:0% +it so you might get a factor of a + + + align:start position:0% +it so you might get a factor of a +hundred reduction by working on both you + + align:start position:0% +hundred reduction by working on both you + + + align:start position:0% +hundred reduction by working on both you +so you've treated the source and you've + + align:start position:0% +so you've treated the source and you've + + + align:start position:0% +so you've treated the source and you've +treated the receiver but fortunately + + align:start position:0% +treated the receiver but fortunately + + + align:start position:0% +treated the receiver but fortunately +they use the same curve now so damping + + align:start position:0% +they use the same curve now so damping + + + align:start position:0% +they use the same curve now so damping +when you do vibration isolation you're + + align:start position:0% +when you do vibration isolation you're + + + align:start position:0% +when you do vibration isolation you're +trying to get well out on this curve to + + align:start position:0% +trying to get well out on this curve to + + + align:start position:0% +trying to get well out on this curve to +the right so there's a couple of + + align:start position:0% +the right so there's a couple of + + + align:start position:0% +the right so there's a couple of +practical engineering things that limit + + align:start position:0% +practical engineering things that limit + + + align:start position:0% +practical engineering things that limit +how far you can go to get further out in + + align:start position:0% +how far you can go to get further out in + + + align:start position:0% +how far you can go to get further out in +the curve to the right what do you have + + align:start position:0% +the curve to the right what do you have + + + align:start position:0% +the curve to the right what do you have +to do to this spring of in the system to + + align:start position:0% +to do to this spring of in the system to + + + align:start position:0% +to do to this spring of in the system to +get stronger or softer you're trying to + + align:start position:0% +get stronger or softer you're trying to + + + align:start position:0% +get stronger or softer you're trying to +make the natural frequency the + + align:start position:0% +make the natural frequency the + + + align:start position:0% +make the natural frequency the +excitation frequency doesn't change in + + align:start position:0% +excitation frequency doesn't change in + + + align:start position:0% +excitation frequency doesn't change in +order to get omega over Omega n to go + + align:start position:0% +order to get omega over Omega n to go + + + align:start position:0% +order to get omega over Omega n to go +bigger and bigger the excitation staying + + align:start position:0% +bigger and bigger the excitation staying + + + align:start position:0% +bigger and bigger the excitation staying +the same every to reduce the natural + + align:start position:0% +the same every to reduce the natural + + + align:start position:0% +the same every to reduce the natural +frequency and so what do you have to do + + align:start position:0% +frequency and so what do you have to do + + + align:start position:0% +frequency and so what do you have to do +to spring constant decrease it what is + + align:start position:0% +to spring constant decrease it what is + + + align:start position:0% +to spring constant decrease it what is +the practical limit of decreasing the + + align:start position:0% +the practical limit of decreasing the + + + align:start position:0% +the practical limit of decreasing the +spring that supports your pump or your + + align:start position:0% +spring that supports your pump or your + + + align:start position:0% +spring that supports your pump or your +washing machine or your air conditioner + + align:start position:0% +washing machine or your air conditioner + + + align:start position:0% +washing machine or your air conditioner +pretty soon it's just going to if it's + + align:start position:0% +pretty soon it's just going to if it's + + + align:start position:0% +pretty soon it's just going to if it's +to hit put it on they're just going to + + align:start position:0% +to hit put it on they're just going to + + + align:start position:0% +to hit put it on they're just going to +squash the springs right so you can't + + align:start position:0% +squash the springs right so you can't + + + align:start position:0% +squash the springs right so you can't +there's limits to how soft you can make + + align:start position:0% +there's limits to how soft you can make + + + align:start position:0% +there's limits to how soft you can make +Springs just support heavy machines so + + align:start position:0% +Springs just support heavy machines so + + + align:start position:0% +Springs just support heavy machines so +there is a practical limit to how far to + + align:start position:0% +there is a practical limit to how far to + + + align:start position:0% +there is a practical limit to how far to +the right you can go but you normally + + align:start position:0% +the right you can go but you normally + + + align:start position:0% +the right you can go but you normally +you get out there as far as you can + + align:start position:0% +you get out there as far as you can + + + align:start position:0% +you get out there as far as you can +and then if you the real system has + + align:start position:0% +and then if you the real system has + + + align:start position:0% +and then if you the real system has +damping does it improve or degrade the + + align:start position:0% +damping does it improve or degrade the + + + align:start position:0% +damping does it improve or degrade the +performance of your vibration isolation + + align:start position:0% +performance of your vibration isolation + + + align:start position:0% +performance of your vibration isolation +system well the more the damping you + + align:start position:0% +system well the more the damping you + + + align:start position:0% +system well the more the damping you +have the higher up you are on those + + align:start position:0% +have the higher up you are on those + + + align:start position:0% +have the higher up you are on those +curves so the damping decreases the + + align:start position:0% +curves so the damping decreases the + + + align:start position:0% +curves so the damping decreases the +performance but every system has to when + + align:start position:0% +performance but every system has to when + + + align:start position:0% +performance but every system has to when +you first turn on that motor the system + + align:start position:0% +you first turn on that motor the system + + + align:start position:0% +you first turn on that motor the system +has to spin up and you're going to have + + align:start position:0% +has to spin up and you're going to have + + + align:start position:0% +has to spin up and you're going to have +to go through that residence so you want + + align:start position:0% +to go through that residence so you want + + + align:start position:0% +to go through that residence so you want +some damping because if you this is if + + align:start position:0% +some damping because if you this is if + + + align:start position:0% +some damping because if you this is if +you've got your scanning electron + + align:start position:0% +you've got your scanning electron + + + align:start position:0% +you've got your scanning electron +microscope or your laser interferometry + + align:start position:0% +microscope or your laser interferometry + + + align:start position:0% +microscope or your laser interferometry +system set up on a on a spring supported + + align:start position:0% +system set up on a on a spring supported + + + align:start position:0% +system set up on a on a spring supported +table if that table has no damping and + + align:start position:0% +table if that table has no damping and + + + align:start position:0% +table if that table has no damping and +you walk in the door and bump it it is + + align:start position:0% +you walk in the door and bump it it is + + + align:start position:0% +you walk in the door and bump it it is +going to sit there and vibrate all + + align:start position:0% +going to sit there and vibrate all + + + align:start position:0% +going to sit there and vibrate all +afternoon at its natural frequency due + + align:start position:0% +afternoon at its natural frequency due + + + align:start position:0% +afternoon at its natural frequency due +to the initial condition so you need + + align:start position:0% +to the initial condition so you need + + + align:start position:0% +to the initial condition so you need +some damping to prevent problems either + + align:start position:0% +some damping to prevent problems either + + + align:start position:0% +some damping to prevent problems either +response to initial conditions or + + align:start position:0% +response to initial conditions or + + + align:start position:0% +response to initial conditions or +bumping it or whatever or even as the + + align:start position:0% +bumping it or whatever or even as the + + + align:start position:0% +bumping it or whatever or even as the +system turns on and speeds up it'll have + + align:start position:0% +system turns on and speeds up it'll have + + + align:start position:0% +system turns on and speeds up it'll have +to go through that resonance and it'll + + align:start position:0% +to go through that resonance and it'll + + + align:start position:0% +to go through that resonance and it'll +vibrate like crazy as it does and then + + align:start position:0% +vibrate like crazy as it does and then + + + align:start position:0% +vibrate like crazy as it does and then +finally settle down at it's at the + + align:start position:0% +finally settle down at it's at the + + + align:start position:0% +finally settle down at it's at the +higher frequency so you need some + + align:start position:0% +higher frequency so you need some + + + align:start position:0% +higher frequency so you need some +damping but damping does degrade the + + align:start position:0% +damping but damping does degrade the + + + align:start position:0% +damping but damping does degrade the +steady-state performance and I'm out of + + align:start position:0% +steady-state performance and I'm out of + + + align:start position:0% +steady-state performance and I'm out of +time and we'll see you in recitation + + align:start position:0% +time and we'll see you in recitation + + + align:start position:0% +time and we'll see you in recitation +thanks \ No newline at end of file diff --git a/f7oXhDatwtY.txt b/f7oXhDatwtY.txt new file mode 100644 index 0000000000000000000000000000000000000000..5439d913dbfe602344914028f0138adc179c44ed --- /dev/null +++ b/f7oXhDatwtY.txt @@ -0,0 +1,7971 @@ +align:start position:0% + +so I will just go through the + + align:start position:0% +so I will just go through the + + + align:start position:0% +so I will just go through the +oldfashioned paper uh syllabus so the + + align:start position:0% +oldfashioned paper uh syllabus so the + + + align:start position:0% +oldfashioned paper uh syllabus so the +course is going to be taught on canvas + + align:start position:0% +course is going to be taught on canvas + + + align:start position:0% +course is going to be taught on canvas +so the canvas site has been published uh + + align:start position:0% +so the canvas site has been published uh + + + align:start position:0% +so the canvas site has been published uh +we will for for uh homeworks and things + + align:start position:0% +we will for for uh homeworks and things + + + align:start position:0% +we will for for uh homeworks and things +like that they'll be handed out and + + align:start position:0% +like that they'll be handed out and + + + align:start position:0% +like that they'll be handed out and +turned in on paper but you can download + + align:start position:0% +turned in on paper but you can download + + + align:start position:0% +turned in on paper but you can download +them from canvas as + + align:start position:0% +them from canvas as + + + align:start position:0% +them from canvas as +well um the classes are going to be here + + align:start position:0% +well um the classes are going to be here + + + align:start position:0% +well um the classes are going to be here +Mondays Wednesdays and Thursdays so on + + align:start position:0% +Mondays Wednesdays and Thursdays so on + + + align:start position:0% +Mondays Wednesdays and Thursdays so on +usual class schedules 1 + + align:start position:0% +usual class schedules 1 + + + align:start position:0% +usual class schedules 1 +pm uh I've mentioned the textbook there + + align:start position:0% +pm uh I've mentioned the textbook there + + + align:start position:0% +pm uh I've mentioned the textbook there +are some other textbooks that you might + + align:start position:0% +are some other textbooks that you might + + + align:start position:0% +are some other textbooks that you might +find Handy and I've listed those in the + + align:start position:0% +find Handy and I've listed those in the + + + align:start position:0% +find Handy and I've listed those in the +course handout those are completely + + align:start position:0% +course handout those are completely + + + align:start position:0% +course handout those are completely +optional you don't have to buy them the + + align:start position:0% +optional you don't have to buy them the + + + align:start position:0% +optional you don't have to buy them the +libraries also have + + align:start position:0% +libraries also have + + + align:start position:0% +libraries also have +copies um the way homeworks will work in + + align:start position:0% +copies um the way homeworks will work in + + + align:start position:0% +copies um the way homeworks will work in +this + + align:start position:0% +this + + + align:start position:0% +this +class is that will typically be issued + + align:start position:0% +class is that will typically be issued + + + align:start position:0% +class is that will typically be issued +on a Monday and do the following Monday + + align:start position:0% +on a Monday and do the following Monday + + + align:start position:0% +on a Monday and do the following Monday +okay and uh for the most part you are + + align:start position:0% +okay and uh for the most part you are + + + align:start position:0% +okay and uh for the most part you are +allowed to collaborate and talk about + + align:start position:0% +allowed to collaborate and talk about + + + align:start position:0% +allowed to collaborate and talk about +the homework problems so you feel free + + align:start position:0% +the homework problems so you feel free + + + align:start position:0% +the homework problems so you feel free +to get together and discuss the problems + + align:start position:0% +to get together and discuss the problems + + + align:start position:0% +to get together and discuss the problems +that there it's intended that you do so + + align:start position:0% +that there it's intended that you do so + + + align:start position:0% +that there it's intended that you do so +the only constraint we have is that you + + align:start position:0% +the only constraint we have is that you + + + align:start position:0% +the only constraint we have is that you +must hand in your own solution right so + + align:start position:0% +must hand in your own solution right so + + + align:start position:0% +must hand in your own solution right so +so you can trade ideas but in the end + + align:start position:0% +so you can trade ideas but in the end + + + align:start position:0% +so you can trade ideas but in the end +the thing you write up it can't be a + + align:start position:0% +the thing you write up it can't be a + + + align:start position:0% +the thing you write up it can't be a +copy your neighbors it has to be your + + align:start position:0% +copy your neighbors it has to be your + + + align:start position:0% +copy your neighbors it has to be your +solution but you can base it on uh you + + align:start position:0% +solution but you can base it on uh you + + + align:start position:0% +solution but you can base it on uh you +know ideas you've exchanged with others + + align:start position:0% +know ideas you've exchanged with others + + + align:start position:0% +know ideas you've exchanged with others +okay for those who don't know + + align:start position:0% +okay for those who don't know + + + align:start position:0% +okay for those who don't know +anybody or or don't have access to study + + align:start position:0% +anybody or or don't have access to study + + + align:start position:0% +anybody or or don't have access to study +partners and may have questions first of + + align:start position:0% +partners and may have questions first of + + + align:start position:0% +partners and may have questions first of +all there will be office hours uh Mon's + + align:start position:0% +all there will be office hours uh Mon's + + + align:start position:0% +all there will be office hours uh Mon's +office hours will be Thursdays 4: to 5: + + align:start position:0% +office hours will be Thursdays 4: to 5: + + + align:start position:0% +office hours will be Thursdays 4: to 5: +p.m. and Fridays 4 to 5:00 P p.m. in + + align:start position:0% +p.m. and Fridays 4 to 5:00 P p.m. in + + + align:start position:0% +p.m. and Fridays 4 to 5:00 P p.m. in +10178 in building 10 okay but there are + + align:start position:0% +10178 in building 10 okay but there are + + + align:start position:0% +10178 in building 10 okay but there are +also a number of students students in + + align:start position:0% +also a number of students students in + + + align:start position:0% +also a number of students students in +the Le laboratory 1050 who have had this + + align:start position:0% +the Le laboratory 1050 who have had this + + + align:start position:0% +the Le laboratory 1050 who have had this +class before will be happy to answer any + + align:start position:0% +class before will be happy to answer any + + + align:start position:0% +class before will be happy to answer any +questions and a few of those students + + align:start position:0% +questions and a few of those students + + + align:start position:0% +questions and a few of those students +are listed in the uh course + + align:start position:0% +are listed in the uh course + + + align:start position:0% +are listed in the uh course +description we've also decided not to + + align:start position:0% +description we've also decided not to + + + align:start position:0% +description we've also decided not to +have exams this term or in-class exams + + align:start position:0% +have exams this term or in-class exams + + + align:start position:0% +have exams this term or in-class exams +rather we're going to have assessments + + align:start position:0% +rather we're going to have assessments + + + align:start position:0% +rather we're going to have assessments +which are essentially take-home mini + + align:start position:0% +which are essentially take-home mini + + + align:start position:0% +which are essentially take-home mini +quizzes uh they will generally be uh um + + align:start position:0% +quizzes uh they will generally be uh um + + + align:start position:0% +quizzes uh they will generally be uh um +they'll be generally issued weekly and + + align:start position:0% +they'll be generally issued weekly and + + + align:start position:0% +they'll be generally issued weekly and +this says they're going to be issued + + align:start position:0% +this says they're going to be issued + + + align:start position:0% +this says they're going to be issued +starting on March 1st I should check if + + align:start position:0% +starting on March 1st I should check if + + + align:start position:0% +starting on March 1st I should check if +that yeah starting on March 1st they'll + + align:start position:0% +that yeah starting on March 1st they'll + + + align:start position:0% +that yeah starting on March 1st they'll +be issued weekly they'll be issued on a + + align:start position:0% +be issued weekly they'll be issued on a + + + align:start position:0% +be issued weekly they'll be issued on a +Wednesday that will be due the next day + + align:start position:0% +Wednesday that will be due the next day + + + align:start position:0% +Wednesday that will be due the next day +Thursday and those will be submitted + + align:start position:0% +Thursday and those will be submitted + + + align:start position:0% +Thursday and those will be submitted +through canvas through grade + + align:start position:0% +through canvas through grade + + + align:start position:0% +through canvas through grade +scope + + align:start position:0% +scope + + + align:start position:0% +scope +um as for homeworks we can take late + + align:start position:0% +um as for homeworks we can take late + + + align:start position:0% +um as for homeworks we can take late +homeworks if you arrange it ahead of + + align:start position:0% +homeworks if you arrange it ahead of + + + align:start position:0% +homeworks if you arrange it ahead of +time and there's some compelling reason + + align:start position:0% +time and there's some compelling reason + + + align:start position:0% +time and there's some compelling reason +why they're late assessments are a + + align:start position:0% +why they're late assessments are a + + + align:start position:0% +why they're late assessments are a +different + + align:start position:0% +different + + + align:start position:0% +different +story also the collaboration policy for + + align:start position:0% +story also the collaboration policy for + + + align:start position:0% +story also the collaboration policy for +assessments is different you cannot + + align:start position:0% +assessments is different you cannot + + + align:start position:0% +assessments is different you cannot +collaborate or discuss the problems at + + align:start position:0% +collaborate or discuss the problems at + + + align:start position:0% +collaborate or discuss the problems at +all for assessments and and you know we + + align:start position:0% +all for assessments and and you know we + + + align:start position:0% +all for assessments and and you know we +can't prove or not prove that you're + + align:start position:0% +can't prove or not prove that you're + + + align:start position:0% +can't prove or not prove that you're +doing so but this is you know this is an + + align:start position:0% +doing so but this is you know this is an + + + align:start position:0% +doing so but this is you know this is an +exam effectively so don't discuss it + + align:start position:0% +exam effectively so don't discuss it + + + align:start position:0% +exam effectively so don't discuss it +with your neighbors and don't discuss + + align:start position:0% +with your neighbors and don't discuss + + + align:start position:0% +with your neighbors and don't discuss +anything until the solutions are out + + align:start position:0% +anything until the solutions are out + + + align:start position:0% +anything until the solutions are out +because there may be people who have + + align:start position:0% +because there may be people who have + + + align:start position:0% +because there may be people who have +made some special arrangement for + + align:start position:0% +made some special arrangement for + + + align:start position:0% +made some special arrangement for +because they're traveling or or for + + align:start position:0% +because they're traveling or or for + + + align:start position:0% +because they're traveling or or for +whatever reason to hand it in late okay + + align:start position:0% +whatever reason to hand it in late okay + + + align:start position:0% +whatever reason to hand it in late okay +so we're going to have homework and + + align:start position:0% +so we're going to have homework and + + + align:start position:0% +so we're going to have homework and +assessments and the goal of the + + align:start position:0% +assessments and the goal of the + + + align:start position:0% +assessments and the goal of the +assessments really is instead of a you + + align:start position:0% +assessments really is instead of a you + + + align:start position:0% +assessments really is instead of a you +sort of very few high stakes + + align:start position:0% +sort of very few high stakes + + + align:start position:0% +sort of very few high stakes +opportunities to show your abilities the + + align:start position:0% +opportunities to show your abilities the + + + align:start position:0% +opportunities to show your abilities the +assessments are sort of distributed in + + align:start position:0% +assessments are sort of distributed in + + + align:start position:0% +assessments are sort of distributed in +low stakes and focused and gives you a + + align:start position:0% +low stakes and focused and gives you a + + + align:start position:0% +low stakes and focused and gives you a +better opportunity to show you what you + + align:start position:0% +better opportunity to show you what you + + + align:start position:0% +better opportunity to show you what you +really know okay so please complete them + + align:start position:0% +really know okay so please complete them + + + align:start position:0% +really know okay so please complete them +entirely on your own no consultation the + + align:start position:0% +entirely on your own no consultation the + + + align:start position:0% +entirely on your own no consultation the +only thing you're allowed to do is ask + + align:start position:0% +only thing you're allowed to do is ask + + + align:start position:0% +only thing you're allowed to do is ask +the core staff clarifying questions just + + align:start position:0% +the core staff clarifying questions just + + + align:start position:0% +the core staff clarifying questions just +the way you might in an exam okay + + align:start position:0% +the way you might in an exam okay + + + align:start position:0% +the way you might in an exam okay +and uh as for the assessments you can + + align:start position:0% +and uh as for the assessments you can + + + align:start position:0% +and uh as for the assessments you can +use any of the course materials you know + + align:start position:0% +use any of the course materials you know + + + align:start position:0% +use any of the course materials you know +read the book whatever you want + + align:start position:0% +read the book whatever you want + + + align:start position:0% +read the book whatever you want +uh do + + align:start position:0% +uh do + + + align:start position:0% +uh do +not go outside and try to use the + + align:start position:0% +not go outside and try to use the + + + align:start position:0% +not go outside and try to use the +worldwide web and for that matter the + + align:start position:0% +worldwide web and for that matter the + + + align:start position:0% +worldwide web and for that matter the +use of Bibles is also prohibited I know + + align:start position:0% +use of Bibles is also prohibited I know + + + align:start position:0% +use of Bibles is also prohibited I know +that there's collections of old 6334 + + align:start position:0% +that there's collections of old 6334 + + + align:start position:0% +that there's collections of old 6334 +materials floating around you're not + + align:start position:0% +materials floating around you're not + + + align:start position:0% +materials floating around you're not +supposed to be Consulting those okay + + align:start position:0% +supposed to be Consulting those okay + + + align:start position:0% +supposed to be Consulting those okay +this just supposed to be a measure of + + align:start position:0% +this just supposed to be a measure of + + + align:start position:0% +this just supposed to be a measure of +what you've learned okay okay so the + + align:start position:0% +what you've learned okay okay so the + + + align:start position:0% +what you've learned okay okay so the +grading will be based on three + + align:start position:0% +grading will be based on three + + + align:start position:0% +grading will be based on three +components homeworks are going to be + + align:start position:0% +components homeworks are going to be + + + align:start position:0% +components homeworks are going to be +40% these assessments will be + + align:start position:0% +40% these assessments will be + + + align:start position:0% +40% these assessments will be +50% and there's also a final project + + align:start position:0% +50% and there's also a final project + + + align:start position:0% +50% and there's also a final project +which is 10% and the final project + + align:start position:0% +which is 10% and the final project + + + align:start position:0% +which is 10% and the final project +sounds like it's only 10% but it's the + + align:start position:0% +sounds like it's only 10% but it's the + + + align:start position:0% +sounds like it's only 10% but it's the +last thing we look at when we're going + + align:start position:0% +last thing we look at when we're going + + + align:start position:0% +last thing we look at when we're going +to assign a grade to everybody and it + + align:start position:0% +to assign a grade to everybody and it + + + align:start position:0% +to assign a grade to everybody and it +really is your opportunity to put + + align:start position:0% +really is your opportunity to put + + + align:start position:0% +really is your opportunity to put +together knowledge that you've learned + + align:start position:0% +together knowledge that you've learned + + + align:start position:0% +together knowledge that you've learned +throughout the class into a real it's on + + align:start position:0% +throughout the class into a real it's on + + + align:start position:0% +throughout the class into a real it's on +paper it's not a it's not a phys phical + + align:start position:0% +paper it's not a it's not a phys phical + + + align:start position:0% +paper it's not a it's not a phys phical +converter you will construct but it's a + + align:start position:0% +converter you will construct but it's a + + + align:start position:0% +converter you will construct but it's a +paper design but it's really your + + align:start position:0% +paper design but it's really your + + + align:start position:0% +paper design but it's really your +opportunity to show us how you've + + align:start position:0% +opportunity to show us how you've + + + align:start position:0% +opportunity to show us how you've +synthesized all this knowledge to be + + align:start position:0% +synthesized all this knowledge to be + + + align:start position:0% +synthesized all this knowledge to be +able to really design Power Electronics + + align:start position:0% +able to really design Power Electronics + + + align:start position:0% +able to really design Power Electronics +and I should say just as an aside in + + align:start position:0% +and I should say just as an aside in + + + align:start position:0% +and I should say just as an aside in +this class we only have a paper design + + align:start position:0% +this class we only have a paper design + + + align:start position:0% +this class we only have a paper design +or or but this complements nicely the + + align:start position:0% +or or but this complements nicely the + + + align:start position:0% +or or but this complements nicely the +undergraduate Power Electronics class + + align:start position:0% +undergraduate Power Electronics class + + + align:start position:0% +undergraduate Power Electronics class +which has a lot of really nice lab + + align:start position:0% +which has a lot of really nice lab + + + align:start position:0% +which has a lot of really nice lab +activities and design activities there + + align:start position:0% +activities and design activities there + + + align:start position:0% +activities and design activities there +so even if you're a graduate student + + align:start position:0% +so even if you're a graduate student + + + align:start position:0% +so even if you're a graduate student +it's it can be a pretty good thing to + + align:start position:0% +it's it can be a pretty good thing to + + + align:start position:0% +it's it can be a pretty good thing to +take in terms of of uh rounding out the + + align:start position:0% +take in terms of of uh rounding out the + + + align:start position:0% +take in terms of of uh rounding out the +LA your lab skill set in this area + + align:start position:0% +LA your lab skill set in this area + + + align:start position:0% +LA your lab skill set in this area +Okay um if you have any necessary + + align:start position:0% +Okay um if you have any necessary + + + align:start position:0% +Okay um if you have any necessary +technical accommodations don't have + + align:start position:0% +technical accommodations don't have + + + align:start position:0% +technical accommodations don't have +access to uh iPads or whatever else you + + align:start position:0% +access to uh iPads or whatever else you + + + align:start position:0% +access to uh iPads or whatever else you +need for grade scope please let us know + + align:start position:0% +need for grade scope please let us know + + + align:start position:0% +need for grade scope please let us know +we'll try to assist uh assist with that + + align:start position:0% + + + + align:start position:0% + +okay so with that are there any + + align:start position:0% +okay so with that are there any + + + align:start position:0% +okay so with that are there any +questions about anything like associated + + align:start position:0% +questions about anything like associated + + + align:start position:0% +questions about anything like associated +with the course + + align:start position:0% + + + + align:start position:0% + +mechanics okay so let me um give you a + + align:start position:0% +mechanics okay so let me um give you a + + + align:start position:0% +mechanics okay so let me um give you a +sense of what this course is going to be + + align:start position:0% +sense of what this course is going to be + + + align:start position:0% +sense of what this course is going to be +about and uh this is one of my favorite + + align:start position:0% +about and uh this is one of my favorite + + + align:start position:0% +about and uh this is one of my favorite +photos is actually one that uh Nicola + + align:start position:0% +photos is actually one that uh Nicola + + + align:start position:0% +photos is actually one that uh Nicola +Tesla mocked up he wasn't really sitting + + align:start position:0% +Tesla mocked up he wasn't really sitting + + + align:start position:0% +Tesla mocked up he wasn't really sitting +next to his Tesla coil when he did this + + align:start position:0% +next to his Tesla coil when he did this + + + align:start position:0% +next to his Tesla coil when he did this +or he might have gotten killed um he + + align:start position:0% +or he might have gotten killed um he + + + align:start position:0% +or he might have gotten killed um he +kind of double exposed this but more to + + align:start position:0% +kind of double exposed this but more to + + + align:start position:0% +kind of double exposed this but more to +the point + + align:start position:0% +the point + + + align:start position:0% +the point +uh the quote from him is if we could + + align:start position:0% +uh the quote from him is if we could + + + align:start position:0% +uh the quote from him is if we could +produce electrical effects of the + + align:start position:0% +produce electrical effects of the + + + align:start position:0% +produce electrical effects of the +required quality this whole planet and + + align:start position:0% +required quality this whole planet and + + + align:start position:0% +required quality this whole planet and +the conditions of existence on it could + + align:start position:0% +the conditions of existence on it could + + + align:start position:0% +the conditions of existence on it could +be transformed and I think the sort of + + align:start position:0% +be transformed and I think the sort of + + + align:start position:0% +be transformed and I think the sort of +the more than a hundred years since he + + align:start position:0% +the more than a hundred years since he + + + align:start position:0% +the more than a hundred years since he +he said that or well more than 100 years + + align:start position:0% +he said that or well more than 100 years + + + align:start position:0% +he said that or well more than 100 years +since he said that uh have borne that + + align:start position:0% +since he said that uh have borne that + + + align:start position:0% +since he said that uh have borne that +out but it's also true that even + + align:start position:0% +out but it's also true that even + + + align:start position:0% +out but it's also true that even +today uh there's really revolutions + + align:start position:0% +today uh there's really revolutions + + + align:start position:0% +today uh there's really revolutions +happening in the way we use energy + + align:start position:0% +happening in the way we use energy + + + align:start position:0% +happening in the way we use energy +everything's being electrified from + + align:start position:0% +everything's being electrified from + + + align:start position:0% +everything's being electrified from +vehicles to transportation to power + + align:start position:0% +vehicles to transportation to power + + + align:start position:0% +vehicles to transportation to power +generation from renewable + + align:start position:0% +generation from renewable + + + align:start position:0% +generation from renewable +resources and um handling all that + + align:start position:0% +resources and um handling all that + + + align:start position:0% +resources and um handling all that +requires some means of processing + + align:start position:0% +requires some means of processing + + + align:start position:0% +requires some means of processing +controlling and converting energy and + + align:start position:0% +controlling and converting energy and + + + align:start position:0% +controlling and converting energy and +that's really what we're about + + align:start position:0% +that's really what we're about + + + align:start position:0% +that's really what we're about +processing controlling converting + + align:start position:0% +processing controlling converting + + + align:start position:0% +processing controlling converting +electrical + + align:start position:0% +electrical + + + align:start position:0% +electrical +energy if you look at what the uh itle e + + align:start position:0% +energy if you look at what the uh itle e + + + align:start position:0% +energy if you look at what the uh itle e +the which is sort of the governing body + + align:start position:0% +the which is sort of the governing body + + + align:start position:0% +the which is sort of the governing body +of electrical engineering says about + + align:start position:0% +of electrical engineering says about + + + align:start position:0% +of electrical engineering says about +Power Electronics it says this + + align:start position:0% +Power Electronics it says this + + + align:start position:0% +Power Electronics it says this +technology encompasses the use of + + align:start position:0% +technology encompasses the use of + + + align:start position:0% +technology encompasses the use of +electronic components + + align:start position:0% +electronic components + + + align:start position:0% +electronic components +the application of circuit Theory and + + align:start position:0% +the application of circuit Theory and + + + align:start position:0% +the application of circuit Theory and +design techniques and the development of + + align:start position:0% +design techniques and the development of + + + align:start position:0% +design techniques and the development of +analytical tools towards efficient + + align:start position:0% +analytical tools towards efficient + + + align:start position:0% +analytical tools towards efficient +electronic conversion control and + + align:start position:0% +electronic conversion control and + + + align:start position:0% +electronic conversion control and +conditioning of electric power and + + align:start position:0% +conditioning of electric power and + + + align:start position:0% +conditioning of electric power and +that's what we're really about here so + + align:start position:0% +that's what we're really about here so + + + align:start position:0% +that's what we're really about here so +we're going to do circuit Theory we're + + align:start position:0% +we're going to do circuit Theory we're + + + align:start position:0% +we're going to do circuit Theory we're +going to learn design techniques we're + + align:start position:0% +going to learn design techniques we're + + + align:start position:0% +going to learn design techniques we're +going to learn about all the components + + align:start position:0% +going to learn about all the components + + + align:start position:0% +going to learn about all the components +you need to do this we're going to learn + + align:start position:0% +you need to do this we're going to learn + + + align:start position:0% +you need to do this we're going to learn +about controls how do you put it all + + align:start position:0% +about controls how do you put it all + + + align:start position:0% +about controls how do you put it all +together to make energy conversion + + align:start position:0% +together to make energy conversion + + + align:start position:0% +together to make energy conversion +systems okay so as I mentioned the + + align:start position:0% +systems okay so as I mentioned the + + + align:start position:0% +systems okay so as I mentioned the +primary function of Power Electronics is + + align:start position:0% +primary function of Power Electronics is + + + align:start position:0% +primary function of Power Electronics is +to take sort of electrical energy in one + + align:start position:0% +to take sort of electrical energy in one + + + align:start position:0% +to take sort of electrical energy in one +form and convert it into some other form + + align:start position:0% +form and convert it into some other form + + + align:start position:0% +form and convert it into some other form +you need uh it's really a core + + align:start position:0% +you need uh it's really a core + + + align:start position:0% +you need uh it's really a core +technology in the electrical + + align:start position:0% +technology in the electrical + + + align:start position:0% +technology in the electrical +infrastructure it used to be that the AC + + align:start position:0% +infrastructure it used to be that the AC + + + align:start position:0% +infrastructure it used to be that the AC +grid was generators and you'd connect it + + align:start position:0% +grid was generators and you'd connect it + + + align:start position:0% +grid was generators and you'd connect it +up to things like directly things like + + align:start position:0% +up to things like directly things like + + + align:start position:0% +up to things like directly things like +Motors or lighting or whatever but + + align:start position:0% +Motors or lighting or whatever but + + + align:start position:0% +Motors or lighting or whatever but +that's pretty much changed at this point + + align:start position:0% +that's pretty much changed at this point + + + align:start position:0% +that's pretty much changed at this point +right lighting is LED lighting you need + + align:start position:0% +right lighting is LED lighting you need + + + align:start position:0% +right lighting is LED lighting you need +power supplies to go between the grid + + align:start position:0% +power supplies to go between the grid + + + align:start position:0% +power supplies to go between the grid +and the lighting same thing heavily + + align:start position:0% +and the lighting same thing heavily + + + align:start position:0% +and the lighting same thing heavily +loads computers Motors everything else + + align:start position:0% +loads computers Motors everything else + + + align:start position:0% +loads computers Motors everything else +you need energy tends to flow through + + align:start position:0% +you need energy tends to flow through + + + align:start position:0% +you need energy tends to flow through +one or even several layers of power + + align:start position:0% +one or even several layers of power + + + align:start position:0% +one or even several layers of power +conversion circuitry from the principal + + align:start position:0% +conversion circuitry from the principal + + + align:start position:0% +conversion circuitry from the principal +source to the final usage okay and so + + align:start position:0% +source to the final usage okay and so + + + align:start position:0% +source to the final usage okay and so +the Power Electronics first of all you + + align:start position:0% +the Power Electronics first of all you + + + align:start position:0% +the Power Electronics first of all you +know the efficiency of that is very + + align:start position:0% +know the efficiency of that is very + + + align:start position:0% +know the efficiency of that is very +important but also how you do it impacts + + align:start position:0% +important but also how you do it impacts + + + align:start position:0% +important but also how you do it impacts +the quality of the final system so the + + align:start position:0% +the quality of the final system so the + + + align:start position:0% +the quality of the final system so the +Power Electronics can really be a major + + align:start position:0% +Power Electronics can really be a major + + + align:start position:0% +Power Electronics can really be a major +factor impacting what you can and can't + + align:start position:0% +factor impacting what you can and can't + + + align:start position:0% +factor impacting what you can and can't +do and how well it works + + align:start position:0% +do and how well it works + + + align:start position:0% +do and how well it works +okay so if you showed up you know + + align:start position:0% +okay so if you showed up you know + + + align:start position:0% +okay so if you showed up you know +hundred years + + align:start position:0% +hundred years + + + align:start position:0% +hundred years +ago this is what Power Electronics would + + align:start position:0% +ago this is what Power Electronics would + + + align:start position:0% +ago this is what Power Electronics would +look like right some vacuum tubes and + + align:start position:0% +look like right some vacuum tubes and + + + align:start position:0% +look like right some vacuum tubes and +some Transformers and that kind of thing + + align:start position:0% +some Transformers and that kind of thing + + + align:start position:0% +some Transformers and that kind of thing +interestingly of course it's nothing + + align:start position:0% +interestingly of course it's nothing + + + align:start position:0% +interestingly of course it's nothing +like that today but with the techniques + + align:start position:0% +like that today but with the techniques + + + align:start position:0% +like that today but with the techniques +you're going to learn in this course you + + align:start position:0% +you're going to learn in this course you + + + align:start position:0% +you're going to learn in this course you +could actually go back and analyze this + + align:start position:0% +could actually go back and analyze this + + + align:start position:0% +could actually go back and analyze this +thing and figure out what it did right + + align:start position:0% +thing and figure out what it did right + + + align:start position:0% +thing and figure out what it did right +so some foundational ideas that we're + + align:start position:0% +so some foundational ideas that we're + + + align:start position:0% +so some foundational ideas that we're +going to come back to which can be 100 + + align:start position:0% +going to come back to which can be 100 + + + align:start position:0% +going to come back to which can be 100 +years old but there's also elements that + + align:start position:0% +years old but there's also elements that + + + align:start position:0% +years old but there's also elements that +are extremely new okay and today you + + align:start position:0% +are extremely new okay and today you + + + align:start position:0% +are extremely new okay and today you +know this this was fancy 100 years ago + + align:start position:0% +know this this was fancy 100 years ago + + + align:start position:0% +know this this was fancy 100 years ago +today Power Electronics is everywhere + + align:start position:0% +today Power Electronics is everywhere + + + align:start position:0% +today Power Electronics is everywhere +from I say from mowatt to gigawatts and + + align:start position:0% +from I say from mowatt to gigawatts and + + + align:start position:0% +from I say from mowatt to gigawatts and +and it does actually use switch mode + + align:start position:0% +and it does actually use switch mode + + + align:start position:0% +and it does actually use switch mode +power conversion down at those power + + align:start position:0% +power conversion down at those power + + + align:start position:0% +power conversion down at those power +levels this is actually a a multi-watt + + align:start position:0% +levels this is actually a a multi-watt + + + align:start position:0% +levels this is actually a a multi-watt +power supply and this is literally at + + align:start position:0% +power supply and this is literally at + + + align:start position:0% +power supply and this is literally at +the gigawatt scale so if you if you go + + align:start position:0% +the gigawatt scale so if you if you go + + + align:start position:0% +the gigawatt scale so if you if you go +out to S the Sandy Pond terminal there + + align:start position:0% +out to S the Sandy Pond terminal there + + + align:start position:0% +out to S the Sandy Pond terminal there +is a power converter that takes two gws + + align:start position:0% +is a power converter that takes two gws + + + align:start position:0% +is a power converter that takes two gws +coming down from Canada hydro and + + align:start position:0% +coming down from Canada hydro and + + + align:start position:0% +coming down from Canada hydro and +converts it to AC to power homes and + + align:start position:0% +converts it to AC to power homes and + + + align:start position:0% +converts it to AC to power homes and +everything else around here right so and + + align:start position:0% +everything else around here right so and + + + align:start position:0% +everything else around here right so and +the techniques that we're going to learn + + align:start position:0% +the techniques that we're going to learn + + + align:start position:0% +the techniques that we're going to learn +in this class really span the entire + + align:start position:0% +in this class really span the entire + + + align:start position:0% +in this class really span the entire +range right so some of the details + + align:start position:0% +range right so some of the details + + + align:start position:0% +range right so some of the details +change and we'll learn about that but + + align:start position:0% +change and we'll learn about that but + + + align:start position:0% +change and we'll learn about that but +there's underlying principles that that + + align:start position:0% +there's underlying principles that that + + + align:start position:0% +there's underlying principles that that +cut across all kinds of electrical + + align:start position:0% +cut across all kinds of electrical + + + align:start position:0% +cut across all kinds of electrical +energy conversion systems + + align:start position:0% +energy conversion systems + + + align:start position:0% +energy conversion systems +okay what kind of applications well + + align:start position:0% +okay what kind of applications well + + + align:start position:0% +okay what kind of applications well +portable Electronics this slightly older + + align:start position:0% +portable Electronics this slightly older + + + align:start position:0% +portable Electronics this slightly older +an iPhone 5 and you think okay iPhones + + align:start position:0% +an iPhone 5 and you think okay iPhones + + + align:start position:0% +an iPhone 5 and you think okay iPhones +got radio transmitters and displays and + + align:start position:0% +got radio transmitters and displays and + + + align:start position:0% +got radio transmitters and displays and +other stuff in it but it turns out that + + align:start position:0% +other stuff in it but it turns out that + + + align:start position:0% +other stuff in it but it turns out that +a large fraction of the volume and board + + align:start position:0% +a large fraction of the volume and board + + + align:start position:0% +a large fraction of the volume and board +area is actually associated with energy + + align:start position:0% +area is actually associated with energy + + + align:start position:0% +area is actually associated with energy +conversion in the thing because no + + align:start position:0% +conversion in the thing because no + + + align:start position:0% +conversion in the thing because no +matter what you're doing you're + + align:start position:0% +matter what you're doing you're + + + align:start position:0% +matter what you're doing you're +processing energy to process information + + align:start position:0% +processing energy to process information + + + align:start position:0% +processing energy to process information +right so something like 40% in this of + + align:start position:0% +right so something like 40% in this of + + + align:start position:0% +right so something like 40% in this of +the motherboard in this example was + + align:start position:0% +the motherboard in this example was + + + align:start position:0% +the motherboard in this example was +associated with power + + align:start position:0% +associated with power + + + align:start position:0% +associated with power +conversion likewise you know at some + + align:start position:0% +conversion likewise you know at some + + + align:start position:0% +conversion likewise you know at some +point you're going to charge your phone + + align:start position:0% +point you're going to charge your phone + + + align:start position:0% +point you're going to charge your phone +or your or your iPad or your computer + + align:start position:0% +or your or your iPad or your computer + + + align:start position:0% +or your or your iPad or your computer +into the wall that's mostly Power + + align:start position:0% +into the wall that's mostly Power + + + align:start position:0% +into the wall that's mostly Power +Electronics too all kinds of computers + + align:start position:0% +Electronics too all kinds of computers + + + align:start position:0% +Electronics too all kinds of computers +if you're in a data center there's + + align:start position:0% +if you're in a data center there's + + + align:start position:0% +if you're in a data center there's +several layers of power conversion + + align:start position:0% +several layers of power conversion + + + align:start position:0% +several layers of power conversion +between the AC group GD and the final + + align:start position:0% +between the AC group GD and the final + + + align:start position:0% +between the AC group GD and the final +set of + + align:start position:0% +set of + + + align:start position:0% +set of +processors okay this is more of what it + + align:start position:0% +processors okay this is more of what it + + + align:start position:0% +processors okay this is more of what it +looks like inside your home computer + + align:start position:0% +looks like inside your home computer + + + align:start position:0% +looks like inside your home computer +we'll actually learn exactly about those + + align:start position:0% +we'll actually learn exactly about those + + + align:start position:0% +we'll actually learn exactly about those +kind of converters and about all the + + align:start position:0% +kind of converters and about all the + + + align:start position:0% +kind of converters and about all the +components that are in them if you're + + align:start position:0% +components that are in them if you're + + + align:start position:0% +components that are in them if you're +going to communicate right the + + align:start position:0% +going to communicate right the + + + align:start position:0% +going to communicate right the +transmitters we tend to think of this as + + align:start position:0% +transmitters we tend to think of this as + + + align:start position:0% +transmitters we tend to think of this as +analog circuits to to make RF + + align:start position:0% +analog circuits to to make RF + + + align:start position:0% +analog circuits to to make RF +transmitters but in fact Power + + align:start position:0% +transmitters but in fact Power + + + align:start position:0% +transmitters but in fact Power +Electronics are heavily embedded in any + + align:start position:0% +Electronics are heavily embedded in any + + + align:start position:0% +Electronics are heavily embedded in any +real communication systems to increase + + align:start position:0% +real communication systems to increase + + + align:start position:0% +real communication systems to increase +the efficiency of transmission + + align:start position:0% +the efficiency of transmission + + + align:start position:0% +the efficiency of transmission +all kinds of commercial applications + + align:start position:0% +all kinds of commercial applications + + + align:start position:0% +all kinds of commercial applications +whether you're you know doing LED + + align:start position:0% +whether you're you know doing LED + + + align:start position:0% +whether you're you know doing LED +lighting or this is actually from some + + align:start position:0% +lighting or this is actually from some + + + align:start position:0% +lighting or this is actually from some +water + + align:start position:0% +water + + + align:start position:0% +water +Purity device but of course it requires + + align:start position:0% +Purity device but of course it requires + + + align:start position:0% +Purity device but of course it requires +a power supply right + + align:start position:0% +a power supply right + + + align:start position:0% +a power supply right +so almost any use of energy these days + + align:start position:0% +so almost any use of energy these days + + + align:start position:0% +so almost any use of energy these days +requires a power + + align:start position:0% +requires a power + + + align:start position:0% +requires a power +supply even in your home I mentioned + + align:start position:0% +supply even in your home I mentioned + + + align:start position:0% +supply even in your home I mentioned +that it used to be that you'd connect + + align:start position:0% +that it used to be that you'd connect + + + align:start position:0% +that it used to be that you'd connect +Motors up to the grid and they'd run and + + align:start position:0% +Motors up to the grid and they'd run and + + + align:start position:0% +Motors up to the grid and they'd run and +maybe You' turn them on and off + + align:start position:0% +maybe You' turn them on and off + + + align:start position:0% +maybe You' turn them on and off +something like that but no longer right + + align:start position:0% +something like that but no longer right + + + align:start position:0% +something like that but no longer right +if you want high performance you need to + + align:start position:0% +if you want high performance you need to + + + align:start position:0% +if you want high performance you need to +be able to modulate that energy so two + + align:start position:0% +be able to modulate that energy so two + + + align:start position:0% +be able to modulate that energy so two +examples here this is for an air + + align:start position:0% +examples here this is for an air + + + align:start position:0% +examples here this is for an air +conditioning unit and it uses an + + align:start position:0% +conditioning unit and it uses an + + + align:start position:0% +conditioning unit and it uses an +inverter a DC to AC converter inside it + + align:start position:0% +inverter a DC to AC converter inside it + + + align:start position:0% +inverter a DC to AC converter inside it +to drive the motor much more quietly and + + align:start position:0% +to drive the motor much more quietly and + + + align:start position:0% +to drive the motor much more quietly and +much more modulated for higher overall + + align:start position:0% +much more modulated for higher overall + + + align:start position:0% +much more modulated for higher overall +system efficiency even your dishwasher + + align:start position:0% +system efficiency even your dishwasher + + + align:start position:0% +system efficiency even your dishwasher +these days has power converters in it + + align:start position:0% +these days has power converters in it + + + align:start position:0% +these days has power converters in it +because it's more efficient in this case + + align:start position:0% +because it's more efficient in this case + + + align:start position:0% +because it's more efficient in this case +quieter to do it that way okay IDE is + + align:start position:0% +quieter to do it that way okay IDE is + + + align:start position:0% +quieter to do it that way okay IDE is +that you might not think of as power + + align:start position:0% +that you might not think of as power + + + align:start position:0% +that you might not think of as power +converters medical applications this is + + align:start position:0% +converters medical applications this is + + + align:start position:0% +converters medical applications this is +this is actually a uh magnetic + + align:start position:0% +this is actually a uh magnetic + + + align:start position:0% +this is actually a uh magnetic +stimulator generates 5,000 amps pulse + + align:start position:0% +stimulator generates 5,000 amps pulse + + + align:start position:0% +stimulator generates 5,000 amps pulse +trains in a transducer coil to throw up + + align:start position:0% +trains in a transducer coil to throw up + + + align:start position:0% +trains in a transducer coil to throw up +magnetic fields that can trigger nerves + + align:start position:0% +magnetic fields that can trigger nerves + + + align:start position:0% +magnetic fields that can trigger nerves +this is an interesting one it's actually + + align:start position:0% +this is an interesting one it's actually + + + align:start position:0% +this is an interesting one it's actually +homework zero so the thing you're + + align:start position:0% +homework zero so the thing you're + + + align:start position:0% +homework zero so the thing you're +analyzing in the first homework just to + + align:start position:0% +analyzing in the first homework just to + + + align:start position:0% +analyzing in the first homework just to +break the rust off is actually this box + + align:start position:0% +break the rust off is actually this box + + + align:start position:0% +break the rust off is actually this box +right here okay scientific applications + + align:start position:0% +right here okay scientific applications + + + align:start position:0% +right here okay scientific applications +you may not be processing energy but + + align:start position:0% +you may not be processing energy but + + + align:start position:0% +you may not be processing energy but +even if you just need to generate + + align:start position:0% +even if you just need to generate + + + align:start position:0% +even if you just need to generate +electric High electrical fields for + + align:start position:0% +electric High electrical fields for + + + align:start position:0% +electric High electrical fields for +whatever reason or magnetic fields as in + + align:start position:0% +whatever reason or magnetic fields as in + + + align:start position:0% +whatever reason or magnetic fields as in +the magnetic stimulator you need energy + + align:start position:0% +the magnetic stimulator you need energy + + + align:start position:0% +the magnetic stimulator you need energy +conversion circuits to do it then + + align:start position:0% +conversion circuits to do it then + + + align:start position:0% +conversion circuits to do it then +there's the sort of the more maybe the + + align:start position:0% +there's the sort of the more maybe the + + + align:start position:0% +there's the sort of the more maybe the +applications you might think of + + align:start position:0% +applications you might think of + + + align:start position:0% +applications you might think of +Transportation right let say that + + align:start position:0% +Transportation right let say that + + + align:start position:0% +Transportation right let say that +electric vehicle or a hybrid vehicle + + align:start position:0% +electric vehicle or a hybrid vehicle + + + align:start position:0% +electric vehicle or a hybrid vehicle +right you + + align:start position:0% +right you + + + align:start position:0% +right you +need Power Electronics to drive the + + align:start position:0% +need Power Electronics to drive the + + + align:start position:0% +need Power Electronics to drive the +energy conversion and this is not a + + align:start position:0% +energy conversion and this is not a + + + align:start position:0% +energy conversion and this is not a +small thing first of all you need the + + align:start position:0% +small thing first of all you need the + + + align:start position:0% +small thing first of all you need the +Power Electronics to drive these things + + align:start position:0% +Power Electronics to drive these things + + + align:start position:0% +Power Electronics to drive these things +right secondly in fact as in one + + align:start position:0% +right secondly in fact as in one + + + align:start position:0% +right secondly in fact as in one +example they redes they + + align:start position:0% +example they redes they + + + align:start position:0% +example they redes they +redesigned the power converter for a + + align:start position:0% +redesigned the power converter for a + + + align:start position:0% +redesigned the power converter for a +Prius the the power train for the Prius + + align:start position:0% +Prius the the power train for the Prius + + + align:start position:0% +Prius the the power train for the Prius +the fuel economy went up by 5% just by + + align:start position:0% +the fuel economy went up by 5% just by + + + align:start position:0% +the fuel economy went up by 5% just by +redesigning the Power Electronics to be + + align:start position:0% +redesigning the Power Electronics to be + + + align:start position:0% +redesigning the Power Electronics to be +better so it has a huge impact on the + + align:start position:0% +better so it has a huge impact on the + + + align:start position:0% +better so it has a huge impact on the +overall application and of course that's + + align:start position:0% +overall application and of course that's + + + align:start position:0% +overall application and of course that's +um electric vehicles but traction right + + align:start position:0% +um electric vehicles but traction right + + + align:start position:0% +um electric vehicles but traction right +trains that's higher power but the same + + align:start position:0% +trains that's higher power but the same + + + align:start position:0% +trains that's higher power but the same +issue + + align:start position:0% +issue + + + align:start position:0% +issue +actually even future trains this it's a + + align:start position:0% +actually even future trains this it's a + + + align:start position:0% +actually even future trains this it's a +little hard to see behind this railing + + align:start position:0% +little hard to see behind this railing + + + align:start position:0% +little hard to see behind this railing +that's a maglev magnetically levitated + + align:start position:0% +that's a maglev magnetically levitated + + + align:start position:0% +that's a maglev magnetically levitated +train along the Wayside over in the back + + align:start position:0% +train along the Wayside over in the back + + + align:start position:0% +train along the Wayside over in the back +corner you see this big building here + + align:start position:0% +corner you see this big building here + + + align:start position:0% +corner you see this big building here +inside that big building as these racks + + align:start position:0% +inside that big building as these racks + + + align:start position:0% +inside that big building as these racks +of Power Electronics now you better have + + align:start position:0% +of Power Electronics now you better have + + + align:start position:0% +of Power Electronics now you better have +pretty reliable Power Electronics if + + align:start position:0% +pretty reliable Power Electronics if + + + align:start position:0% +pretty reliable Power Electronics if +your vehicle's flying along at 400 kmers + + align:start position:0% +your vehicle's flying along at 400 kmers + + + align:start position:0% +your vehicle's flying along at 400 kmers +an hour floating on you know that far + + align:start position:0% +an hour floating on you know that far + + + align:start position:0% +an hour floating on you know that far +off the ground right so not only do you + + align:start position:0% +off the ground right so not only do you + + + align:start position:0% +off the ground right so not only do you +need efficiency but you need reliability + + align:start position:0% +need efficiency but you need reliability + + + align:start position:0% +need efficiency but you need reliability +and precision okay even Strang + + align:start position:0% +and precision okay even Strang + + + align:start position:0% +and precision okay even Strang +things uh this is this is an example of + + align:start position:0% +things uh this is this is an example of + + + align:start position:0% +things uh this is this is an example of +a drone just by powered by high voltage + + align:start position:0% +a drone just by powered by high voltage + + + align:start position:0% +a drone just by powered by high voltage +right you just apply high voltage it + + align:start position:0% +right you just apply high voltage it + + + align:start position:0% +right you just apply high voltage it +breaks down the air accelerates ions and + + align:start position:0% +breaks down the air accelerates ions and + + + align:start position:0% +breaks down the air accelerates ions and +you can use that for propulsion that's + + align:start position:0% +you can use that for propulsion that's + + + align:start position:0% +you can use that for propulsion that's +the first demonstration of it but it + + align:start position:0% +the first demonstration of it but it + + + align:start position:0% +the first demonstration of it but it +actually it's very similar in some + + align:start position:0% +actually it's very similar in some + + + align:start position:0% +actually it's very similar in some +regards to what people use for space + + align:start position:0% +regards to what people use for space + + + align:start position:0% +regards to what people use for space +propulsion you've heard of ion engines + + align:start position:0% +propulsion you've heard of ion engines + + + align:start position:0% +propulsion you've heard of ion engines +right the twin ion engine TIE fighter or + + align:start position:0% +right the twin ion engine TIE fighter or + + + align:start position:0% +right the twin ion engine TIE fighter or +what more practically they use to uh to + + align:start position:0% +what more practically they use to uh to + + + align:start position:0% +what more practically they use to uh to +reposition satellites those require + + align:start position:0% +reposition satellites those require + + + align:start position:0% +reposition satellites those require +Power Electronics to generate high + + align:start position:0% +Power Electronics to generate high + + + align:start position:0% +Power Electronics to generate high +voltages and accelerate ions okay Power + + align:start position:0% +voltages and accelerate ions okay Power + + + align:start position:0% +voltages and accelerate ions okay Power +transmission and generation right that's + + align:start position:0% +transmission and generation right that's + + + align:start position:0% +transmission and generation right that's +so you're getting your energy from + + align:start position:0% +so you're getting your energy from + + + align:start position:0% +so you're getting your energy from +somewhere and increasingly we're getting + + align:start position:0% +somewhere and increasingly we're getting + + + align:start position:0% +somewhere and increasingly we're getting +it from renewable resources well + + align:start position:0% +it from renewable resources well + + + align:start position:0% +it from renewable resources well +generally the way things are trending + + align:start position:0% +generally the way things are trending + + + align:start position:0% +generally the way things are trending +you take some mechanical or solar or + + align:start position:0% +you take some mechanical or solar or + + + align:start position:0% +you take some mechanical or solar or +other source of energy and you + + align:start position:0% +other source of energy and you + + + align:start position:0% +other source of energy and you +transition it not only through a + + align:start position:0% +transition it not only through a + + + align:start position:0% +transition it not only through a +generator but through Power Electronics + + align:start position:0% +generator but through Power Electronics + + + align:start position:0% +generator but through Power Electronics +to get there and that's true for + + align:start position:0% +to get there and that's true for + + + align:start position:0% +to get there and that's true for +terrestrial things things like this is a + + align:start position:0% +terrestrial things things like this is a + + + align:start position:0% +terrestrial things things like this is a +house rooftop PV system this is a micro + + align:start position:0% +house rooftop PV system this is a micro + + + align:start position:0% +house rooftop PV system this is a micro +inverter + + align:start position:0% +inverter + + + align:start position:0% +inverter +um + + align:start position:0% +um + + + align:start position:0% +um +Automotive Systems or even much smaller + + align:start position:0% +Automotive Systems or even much smaller + + + align:start position:0% +Automotive Systems or even much smaller +things like uh + + align:start position:0% +things like uh + + + align:start position:0% +things like uh +uh Power harvesting energy harvesting + + align:start position:0% +uh Power harvesting energy harvesting + + + align:start position:0% +uh Power harvesting energy harvesting +techniques you need Power Electronics in + + align:start position:0% +techniques you need Power Electronics in + + + align:start position:0% +techniques you need Power Electronics in +it also all kinds of industrial + + align:start position:0% +it also all kinds of industrial + + + align:start position:0% +it also all kinds of industrial +applications whether you're doing uh + + align:start position:0% +applications whether you're doing uh + + + align:start position:0% +applications whether you're doing uh +plasma processing for Semiconductor + + align:start position:0% +plasma processing for Semiconductor + + + align:start position:0% +plasma processing for Semiconductor +processing or you know you want to + + align:start position:0% +processing or you know you want to + + + align:start position:0% +processing or you know you want to +refine metals like a DC Arc furnace you + + align:start position:0% +refine metals like a DC Arc furnace you + + + align:start position:0% +refine metals like a DC Arc furnace you +need Power Electronics there too okay so + + align:start position:0% +need Power Electronics there too okay so + + + align:start position:0% +need Power Electronics there too okay so +that's just sort of a way long way of + + align:start position:0% +that's just sort of a way long way of + + + align:start position:0% +that's just sort of a way long way of +saying power electronics are in almost + + align:start position:0% +saying power electronics are in almost + + + align:start position:0% +saying power electronics are in almost +everything you care about these days and + + align:start position:0% +everything you care about these days and + + + align:start position:0% +everything you care about these days and +it's only getting more so because we + + align:start position:0% +it's only getting more so because we + + + align:start position:0% +it's only getting more so because we +have to be better about how we use + + align:start position:0% +have to be better about how we use + + + align:start position:0% +have to be better about how we use +energy + + align:start position:0% + + + + align:start position:0% + +okay so what's inside a power converter + + align:start position:0% +okay so what's inside a power converter + + + align:start position:0% +okay so what's inside a power converter +and we're going to talk about this in + + align:start position:0% +and we're going to talk about this in + + + align:start position:0% +and we're going to talk about this in +much greater detail but if you want to + + align:start position:0% +much greater detail but if you want to + + + align:start position:0% +much greater detail but if you want to +think about it what we have + + align:start position:0% +think about it what we have + + + align:start position:0% +think about it what we have +is typically some kind of energy storage + + align:start position:0% +is typically some kind of energy storage + + + align:start position:0% +is typically some kind of energy storage +elements these could be inductors or + + align:start position:0% +elements these could be inductors or + + + align:start position:0% +elements these could be inductors or +capacitors or sometimes other things and + + align:start position:0% +capacitors or sometimes other things and + + + align:start position:0% +capacitors or sometimes other things and +what we're going to do is we're going to + + align:start position:0% +what we're going to do is we're going to + + + align:start position:0% +what we're going to do is we're going to +use semiconductor switches and we're + + align:start position:0% +use semiconductor switches and we're + + + align:start position:0% +use semiconductor switches and we're +going to draw energy from some Source + + align:start position:0% +going to draw energy from some Source + + + align:start position:0% +going to draw energy from some Source +we're going to manipulate it somehow so + + align:start position:0% +we're going to manipulate it somehow so + + + align:start position:0% +we're going to manipulate it somehow so +we store it in these energy storage + + align:start position:0% +we store it in these energy storage + + + align:start position:0% +we store it in these energy storage +elements and then we're going to put it + + align:start position:0% +elements and then we're going to put it + + + align:start position:0% +elements and then we're going to put it +to the output and we're going to repeat + + align:start position:0% +to the output and we're going to repeat + + + align:start position:0% +to the output and we're going to repeat +that right so draw transform put it to + + align:start position:0% +that right so draw transform put it to + + + align:start position:0% +that right so draw transform put it to +the output okay because we do this on a + + align:start position:0% +the output okay because we do this on a + + + align:start position:0% +the output okay because we do this on a +cyclic + + align:start position:0% +cyclic + + + align:start position:0% +cyclic +basis we generate sort of Ripple and + + align:start position:0% +basis we generate sort of Ripple and + + + align:start position:0% +basis we generate sort of Ripple and +potentially noise that could interfere + + align:start position:0% +potentially noise that could interfere + + + align:start position:0% +potentially noise that could interfere +with things like television or + + align:start position:0% +with things like television or + + + align:start position:0% +with things like television or +Electronics so you generally need + + align:start position:0% +Electronics so you generally need + + + align:start position:0% +Electronics so you generally need +filters to do that too we also of course + + align:start position:0% +filters to do that too we also of course + + + align:start position:0% +filters to do that too we also of course +need to control that flow of energy + + align:start position:0% +need to control that flow of energy + + + align:start position:0% +need to control that flow of energy +right we can't be stupid about it we + + align:start position:0% +right we can't be stupid about it we + + + align:start position:0% +right we can't be stupid about it we +have especially for something high + + align:start position:0% +have especially for something high + + + align:start position:0% +have especially for something high +performance like a microprocessor which + + align:start position:0% +performance like a microprocessor which + + + align:start position:0% +performance like a microprocessor which +might be changing its operation very + + align:start position:0% +might be changing its operation very + + + align:start position:0% +might be changing its operation very +very fast we need to control that flow + + align:start position:0% +very fast we need to control that flow + + + align:start position:0% +very fast we need to control that flow +so there's control circuitry we're going + + align:start position:0% +so there's control circuitry we're going + + + align:start position:0% +so there's control circuitry we're going +to be learning about all of the aspects + + align:start position:0% +to be learning about all of the aspects + + + align:start position:0% +to be learning about all of the aspects +of Designing + + align:start position:0% +of Designing + + + align:start position:0% +of Designing +all of these kinds of elements + + align:start position:0% +all of these kinds of elements + + + align:start position:0% +all of these kinds of elements +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so we're leveraging sort of everything + + align:start position:0% +so we're leveraging sort of everything + + + align:start position:0% +so we're leveraging sort of everything +from circuit design semiconductor + + align:start position:0% +from circuit design semiconductor + + + align:start position:0% +from circuit design semiconductor +devices passive components and materials + + align:start position:0% +devices passive components and materials + + + align:start position:0% +devices passive components and materials +increasingly packaging and Cooling and + + align:start position:0% +increasingly packaging and Cooling and + + + align:start position:0% +increasingly packaging and Cooling and +controls also matter and things have + + align:start position:0% +controls also matter and things have + + + align:start position:0% +controls also matter and things have +been getting better and better and + + align:start position:0% +been getting better and better and + + + align:start position:0% +been getting better and better and +better both because the um ways we can + + align:start position:0% +better both because the um ways we can + + + align:start position:0% +better both because the um ways we can +manufacture things get better and + + align:start position:0% +manufacture things get better and + + + align:start position:0% +manufacture things get better and +because the devices which we have + + align:start position:0% +because the devices which we have + + + align:start position:0% +because the devices which we have +our access to in order to implement + + align:start position:0% +our access to in order to implement + + + align:start position:0% +our access to in order to implement +these things get better okay and so + + align:start position:0% +these things get better okay and so + + + align:start position:0% +these things get better okay and so +we're going to look at some of the + + align:start position:0% +we're going to look at some of the + + + align:start position:0% +we're going to look at some of the +different ways you can do that I'll just + + align:start position:0% +different ways you can do that I'll just + + + align:start position:0% +different ways you can do that I'll just +give you + + align:start position:0% +give you + + + align:start position:0% +give you +uh one example this is what you would + + align:start position:0% +uh one example this is what you would + + + align:start position:0% +uh one example this is what you would +find something like in a data center + + align:start position:0% +find something like in a data center + + + align:start position:0% +find something like in a data center +right so they come in they rectify the + + align:start position:0% +right so they come in they rectify the + + + align:start position:0% +right so they come in they rectify the +voltage they get it to sort of 400 Volts + + align:start position:0% +voltage they get it to sort of 400 Volts + + + align:start position:0% +voltage they get it to sort of 400 Volts +for reasons we'll go into this converter + + align:start position:0% +for reasons we'll go into this converter + + + align:start position:0% +for reasons we'll go into this converter +here was designed to take that 400 volts + + align:start position:0% +here was designed to take that 400 volts + + + align:start position:0% +here was designed to take that 400 volts +and bring it down to 12 volts okay + + align:start position:0% +and bring it down to 12 volts okay + + + align:start position:0% +and bring it down to 12 volts okay +that that tiny little thing a little bit + + align:start position:0% +that that tiny little thing a little bit + + + align:start position:0% +that that tiny little thing a little bit +bigger than a penny there actually can + + align:start position:0% +bigger than a penny there actually can + + + align:start position:0% +bigger than a penny there actually can +handle a kilowatt then you need more + + align:start position:0% +handle a kilowatt then you need more + + + align:start position:0% +handle a kilowatt then you need more +converters to take it down from there to + + align:start position:0% +converters to take it down from there to + + + align:start position:0% +converters to take it down from there to +the one VT that the processor uses okay + + align:start position:0% +the one VT that the processor uses okay + + + align:start position:0% +the one VT that the processor uses okay +so the sort of a long way of saying all + + align:start position:0% +so the sort of a long way of saying all + + + align:start position:0% +so the sort of a long way of saying all +kinds of things are limited by energy + + align:start position:0% +kinds of things are limited by energy + + + align:start position:0% +kinds of things are limited by energy +and how we can control it right across + + align:start position:0% +and how we can control it right across + + + align:start position:0% +and how we can control it right across +all these applications and what we're + + align:start position:0% +all these applications and what we're + + + align:start position:0% +all these applications and what we're +usually trying to do is how figure out + + align:start position:0% +usually trying to do is how figure out + + + align:start position:0% +usually trying to do is how figure out +how to make them smaller and lighter + + align:start position:0% +how to make them smaller and lighter + + + align:start position:0% +how to make them smaller and lighter +right if you're taking up 40% of your + + align:start position:0% +right if you're taking up 40% of your + + + align:start position:0% +right if you're taking up 40% of your +iPhone you want + + align:start position:0% +iPhone you want + + + align:start position:0% +iPhone you want +make that thing smaller so it doesn't + + align:start position:0% +make that thing smaller so it doesn't + + + align:start position:0% +make that thing smaller so it doesn't +take that up and you can replace that + + align:start position:0% +take that up and you can replace that + + + align:start position:0% +take that up and you can replace that +volume either with nothing or with + + align:start position:0% +volume either with nothing or with + + + align:start position:0% +volume either with nothing or with +things that are more interesting to you + + align:start position:0% +things that are more interesting to you + + + align:start position:0% +things that are more interesting to you +we need higher efficiency both for the + + align:start position:0% +we need higher efficiency both for the + + + align:start position:0% +we need higher efficiency both for the +converters and the systems how we + + align:start position:0% +converters and the systems how we + + + align:start position:0% +converters and the systems how we +process energy can matter to the not + + align:start position:0% +process energy can matter to the not + + + align:start position:0% +process energy can matter to the not +only the ultimate efficiency of the + + align:start position:0% +only the ultimate efficiency of the + + + align:start position:0% +only the ultimate efficiency of the +converter but the efficiency of the + + align:start position:0% +converter but the efficiency of the + + + align:start position:0% +converter but the efficiency of the +system how it uses energy can be + + align:start position:0% +system how it uses energy can be + + + align:start position:0% +system how it uses energy can be +determined by the Power Electronics we + + align:start position:0% +determined by the Power Electronics we + + + align:start position:0% +determined by the Power Electronics we +want higher performance that could mean + + align:start position:0% +want higher performance that could mean + + + align:start position:0% +want higher performance that could mean +higher bandwidth or other aspects and + + align:start position:0% +higher bandwidth or other aspects and + + + align:start position:0% +higher bandwidth or other aspects and +then there's all kinds of means that we + + align:start position:0% +then there's all kinds of means that we + + + align:start position:0% +then there's all kinds of means that we +we can use better electrical processing + + align:start position:0% +we can use better electrical processing + + + align:start position:0% +we can use better electrical processing +to enable new applications so these are + + align:start position:0% +to enable new applications so these are + + + align:start position:0% +to enable new applications so these are +the kind of things that we're going to + + align:start position:0% +the kind of things that we're going to + + + align:start position:0% +the kind of things that we're going to +learn about this term I'll pause there + + align:start position:0% +learn about this term I'll pause there + + + align:start position:0% +learn about this term I'll pause there +i' I've been going on a while are there + + align:start position:0% +i' I've been going on a while are there + + + align:start position:0% +i' I've been going on a while are there +any questions about any of this before + + align:start position:0% +any questions about any of this before + + + align:start position:0% +any questions about any of this before +we get going this is just to sort of + + align:start position:0% +we get going this is just to sort of + + + align:start position:0% +we get going this is just to sort of +Orient you as to what we're going to + + align:start position:0% +Orient you as to what we're going to + + + align:start position:0% +Orient you as to what we're going to +focus the term + + align:start position:0% + + + + align:start position:0% + +on I can put the slides on canvas + + align:start position:0% +on I can put the slides on canvas + + + align:start position:0% +on I can put the slides on canvas +sure any other + + align:start position:0% + + + + align:start position:0% + +questions okay + + align:start position:0% + + + + align:start position:0% + +okay I will just give + + align:start position:0% +okay I will just give + + + align:start position:0% +okay I will just give +you a slight + + align:start position:0% +you a slight + + + align:start position:0% +you a slight +notion okay just and this is a + + align:start position:0% +notion okay just and this is a + + + align:start position:0% +notion okay just and this is a +favorite thing I like to bring in just + + align:start position:0% +favorite thing I like to bring in just + + + align:start position:0% +favorite thing I like to bring in just +to show you the kind of things we're + + align:start position:0% +to show you the kind of things we're + + + align:start position:0% +to show you the kind of things we're +going to look at this + + align:start position:0% +going to look at this + + + align:start position:0% +going to look at this +term this is a piece of commercial + + align:start position:0% +term this is a piece of commercial + + + align:start position:0% +term this is a piece of commercial +Hardware from a company called MKS + + align:start position:0% +Hardware from a company called MKS + + + align:start position:0% +Hardware from a company called MKS +instruments that I just happen to have + + align:start position:0% +instruments that I just happen to have + + + align:start position:0% +instruments that I just happen to have +in my + + align:start position:0% +in my + + + align:start position:0% +in my +office this input piece is a filter so + + align:start position:0% +office this input piece is a filter so + + + align:start position:0% +office this input piece is a filter so +you don't create electrom magnetic + + align:start position:0% +you don't create electrom magnetic + + + align:start position:0% +you don't create electrom magnetic +interference and you don't generate + + align:start position:0% +interference and you don't generate + + + align:start position:0% +interference and you don't generate +noise you don't + + align:start position:0% +noise you don't + + + align:start position:0% +noise you don't +want then this piece here takes energy + + align:start position:0% +want then this piece here takes energy + + + align:start position:0% +want then this piece here takes energy +from the 60 HZ grid and generates DC + + align:start position:0% +from the 60 HZ grid and generates DC + + + align:start position:0% +from the 60 HZ grid and generates DC +from it and it has to do it while making + + align:start position:0% +from it and it has to do it while making + + + align:start position:0% +from it and it has to do it while making +the whole thing look like a resistor to + + align:start position:0% +the whole thing look like a resistor to + + + align:start position:0% +the whole thing look like a resistor to +the grid so you don't mess up the grid + + align:start position:0% +the grid so you don't mess up the grid + + + align:start position:0% +the grid so you don't mess up the grid +okay that's what this part does then it + + align:start position:0% +okay that's what this part does then it + + + align:start position:0% +okay that's what this part does then it +has these isolated dcdc converters that + + align:start position:0% +has these isolated dcdc converters that + + + align:start position:0% +has these isolated dcdc converters that +can take that DC voltage and generate + + align:start position:0% +can take that DC voltage and generate + + + align:start position:0% +can take that DC voltage and generate +other DC voltages referenced in other + + align:start position:0% +other DC voltages referenced in other + + + align:start position:0% +other DC voltages referenced in other +ways and without worrying about uh sort + + align:start position:0% +ways and without worrying about uh sort + + + align:start position:0% +ways and without worrying about uh sort +of currents going back to ground okay + + align:start position:0% +of currents going back to ground okay + + + align:start position:0% +of currents going back to ground okay +it's galvanically isolated and then it + + align:start position:0% +it's galvanically isolated and then it + + + align:start position:0% +it's galvanically isolated and then it +takes that energy and goes back DC to AC + + align:start position:0% +takes that energy and goes back DC to AC + + + align:start position:0% +takes that energy and goes back DC to AC +okay now in some systems you might go DC + + align:start position:0% +okay now in some systems you might go DC + + + align:start position:0% +okay now in some systems you might go DC +to AC for 60 hertz to to generate into + + align:start position:0% +to AC for 60 hertz to to generate into + + + align:start position:0% +to AC for 60 hertz to to generate into +the Grid or for a motor or something + + align:start position:0% +the Grid or for a motor or something + + + align:start position:0% +the Grid or for a motor or something +else this particular one has these + + align:start position:0% +else this particular one has these + + + align:start position:0% +else this particular one has these +outputs that are at 13 megahertz for + + align:start position:0% +outputs that are at 13 megahertz for + + + align:start position:0% +outputs that are at 13 megahertz for +driving plasmas to process + + align:start position:0% +driving plasmas to process + + + align:start position:0% +driving plasmas to process +semiconductors okay but you get all + + align:start position:0% +semiconductors okay but you get all + + + align:start position:0% +semiconductors okay but you get all +these kind of functions AC to DC DC to + + align:start position:0% +these kind of functions AC to DC DC to + + + align:start position:0% +these kind of functions AC to DC DC to +DC DC to AC and we're going to learn the + + align:start position:0% +DC DC to AC and we're going to learn the + + + align:start position:0% +DC DC to AC and we're going to learn the +first of all the + + align:start position:0% +first of all the + + + align:start position:0% +first of all the +underlying uh principles of doing all + + align:start position:0% +underlying uh principles of doing all + + + align:start position:0% +underlying uh principles of doing all +these things and how to design them okay + + align:start position:0% +these things and how to design them okay + + + align:start position:0% +these things and how to design them okay +so the the the real goal + + align:start position:0% +so the the the real goal + + + align:start position:0% +so the the the real goal +is by the time you walk out of here you + + align:start position:0% +is by the time you walk out of here you + + + align:start position:0% +is by the time you walk out of here you +should have all the tools to go off and + + align:start position:0% +should have all the tools to go off and + + + align:start position:0% +should have all the tools to go off and +design Power + + align:start position:0% +design Power + + + align:start position:0% +design Power +Electronics for all kinds of + + align:start position:0% +Electronics for all kinds of + + + align:start position:0% +Electronics for all kinds of +applications and and in fact graduates + + align:start position:0% +applications and and in fact graduates + + + align:start position:0% +applications and and in fact graduates +of this + + align:start position:0% +of this + + + align:start position:0% +of this +class have worked on electric vehicles + + align:start position:0% +class have worked on electric vehicles + + + align:start position:0% +class have worked on electric vehicles +Char battery charger + + align:start position:0% +Char battery charger + + + align:start position:0% +Char battery charger +solar + + align:start position:0% +solar + + + align:start position:0% +solar +uh communication + + align:start position:0% +uh communication + + + align:start position:0% +uh communication +systems data + + align:start position:0% +systems data + + + align:start position:0% +systems data +centers the in fact the the power supply + + align:start position:0% +centers the in fact the the power supply + + + align:start position:0% +centers the in fact the the power supply +I usually use for my laptop and the in + + align:start position:0% +I usually use for my laptop and the in + + + align:start position:0% +I usually use for my laptop and the in +fact the wireless charger for my + + align:start position:0% +fact the wireless charger for my + + + align:start position:0% +fact the wireless charger for my +eyewatch were all designed or the teams + + align:start position:0% +eyewatch were all designed or the teams + + + align:start position:0% +eyewatch were all designed or the teams +were led by graduates of this class + + align:start position:0% +were led by graduates of this class + + + align:start position:0% +were led by graduates of this class +right so this the goal is to give you + + align:start position:0% +right so this the goal is to give you + + + align:start position:0% +right so this the goal is to give you +the tools you need to go do these things + + align:start position:0% +the tools you need to go do these things + + + align:start position:0% +the tools you need to go do these things +okay so with + + align:start position:0% +okay so with + + + align:start position:0% +okay so with +that um let me + + align:start position:0% +that um let me + + + align:start position:0% +that um let me +start by just giving you a sense + + align:start position:0% +start by just giving you a sense + + + align:start position:0% +start by just giving you a sense +of + + align:start position:0% +of + + + align:start position:0% +of +um what goes on inside Power + + align:start position:0% + + + + align:start position:0% + +Electronics so let's think of the + + align:start position:0% +Electronics so let's think of the + + + align:start position:0% +Electronics so let's think of the +simplest case I have some DC input + + align:start position:0% +simplest case I have some DC input + + + align:start position:0% +simplest case I have some DC input +voltage and I'd like some other DC + + align:start position:0% +voltage and I'd like some other DC + + + align:start position:0% +voltage and I'd like some other DC +voltage so suppose I have some + + align:start position:0% + + + + align:start position:0% + +input that's you know maybe it's 9 volts + + align:start position:0% +input that's you know maybe it's 9 volts + + + align:start position:0% +input that's you know maybe it's 9 volts +to 6 16 + + align:start position:0% +to 6 16 + + + align:start position:0% +to 6 16 +Vols I'm making that up arbitrarily but + + align:start position:0% +Vols I'm making that up arbitrarily but + + + align:start position:0% +Vols I'm making that up arbitrarily but +that's roughly what you might get in a + + align:start position:0% +that's roughly what you might get in a + + + align:start position:0% +that's roughly what you might get in a +typical vehicle right out of the + + align:start position:0% +typical vehicle right out of the + + + align:start position:0% +typical vehicle right out of the +cigarette lighter + + align:start position:0% +cigarette lighter + + + align:start position:0% +cigarette lighter +okay and suppose I want and I'll call + + align:start position:0% +okay and suppose I want and I'll call + + + align:start position:0% +okay and suppose I want and I'll call +this + + align:start position:0% +this + + + align:start position:0% +this +VN and suppose I want here's some load + + align:start position:0% +VN and suppose I want here's some load + + + align:start position:0% +VN and suppose I want here's some load +that I'm going to represent with a + + align:start position:0% +that I'm going to represent with a + + + align:start position:0% +that I'm going to represent with a +resistor I'm going to call that V out + + align:start position:0% +resistor I'm going to call that V out + + + align:start position:0% +resistor I'm going to call that V out +okay and suppose I want EG 5 + + align:start position:0% +okay and suppose I want EG 5 + + + align:start position:0% +okay and suppose I want EG 5 +volts right to power something that + + align:start position:0% +volts right to power something that + + + align:start position:0% +volts right to power something that +takes five volts + + align:start position:0% +takes five volts + + + align:start position:0% +takes five volts +right what's the most obvious and simple + + align:start position:0% +right what's the most obvious and simple + + + align:start position:0% +right what's the most obvious and simple +way to get 5 volts at my output from + + align:start position:0% +way to get 5 volts at my output from + + + align:start position:0% +way to get 5 volts at my output from +some higher + + align:start position:0% + + + + align:start position:0% + +voltage voltage divider precisely right + + align:start position:0% +voltage voltage divider precisely right + + + align:start position:0% +voltage voltage divider precisely right +I could come up here I could say okay + + align:start position:0% +I could come up here I could say okay + + + align:start position:0% +I could come up here I could say okay +let me put + + align:start position:0% + + + + align:start position:0% + +in some volt variable + + align:start position:0% +in some volt variable + + + align:start position:0% +in some volt variable +resistor and I'll drop down this voltage + + align:start position:0% +resistor and I'll drop down this voltage + + + align:start position:0% +resistor and I'll drop down this voltage +to give me the voltage I want and I'm + + align:start position:0% +to give me the voltage I want and I'm + + + align:start position:0% +to give me the voltage I want and I'm +done and in fact a lot of systems that's + + align:start position:0% +done and in fact a lot of systems that's + + + align:start position:0% +done and in fact a lot of systems that's +exactly more or less what they have + + align:start position:0% +exactly more or less what they have + + + align:start position:0% +exactly more or less what they have +inside them in fact inside most + + align:start position:0% +inside them in fact inside most + + + align:start position:0% +inside them in fact inside most +integrated circuits there's lots of + + align:start position:0% +integrated circuits there's lots of + + + align:start position:0% +integrated circuits there's lots of +these things going on okay well okay + + align:start position:0% +these things going on okay well okay + + + align:start position:0% +these things going on okay well okay +they don't do it quite this way what do + + align:start position:0% +they don't do it quite this way what do + + + align:start position:0% +they don't do it quite this way what do +they really do + + align:start position:0% + + + + align:start position:0% + +they will take VN and what they will do + + align:start position:0% +they will take VN and what they will do + + + align:start position:0% +they will take VN and what they will do +is they'll use some kind of transistor a + + align:start position:0% +is they'll use some kind of transistor a + + + align:start position:0% +is they'll use some kind of transistor a +mosfet or a bipolar + + align:start position:0% +mosfet or a bipolar + + + align:start position:0% +mosfet or a bipolar +transistor and they will treat that + + align:start position:0% +transistor and they will treat that + + + align:start position:0% +transistor and they will treat that +essentially as a variable resistor right + + align:start position:0% +essentially as a variable resistor right + + + align:start position:0% +essentially as a variable resistor right +so I implement the variable resistor + + align:start position:0% +so I implement the variable resistor + + + align:start position:0% +so I implement the variable resistor +with a controlled transistor and I will + + align:start position:0% +with a controlled transistor and I will + + + align:start position:0% +with a controlled transistor and I will +come and I'll have some feedback loop + + align:start position:0% +come and I'll have some feedback loop + + + align:start position:0% +come and I'll have some feedback loop +I'll Fe feed in a reference + + align:start position:0% +I'll Fe feed in a reference + + + align:start position:0% +I'll Fe feed in a reference +voltage and I'll measure the output + + align:start position:0% +voltage and I'll measure the output + + + align:start position:0% +voltage and I'll measure the output +voltage and I'll control the Gate of + + align:start position:0% +voltage and I'll control the Gate of + + + align:start position:0% +voltage and I'll control the Gate of +this transistor and essentially make + + align:start position:0% +this transistor and essentially make + + + align:start position:0% +this transistor and essentially make +that transistor look like a variable + + align:start position:0% +that transistor look like a variable + + + align:start position:0% +that transistor look like a variable +resistor and control the voltage + + align:start position:0% +resistor and control the voltage + + + align:start position:0% +resistor and control the voltage +division so that even if this voltage + + align:start position:0% +division so that even if this voltage + + + align:start position:0% +division so that even if this voltage +varies between 9 and 16 volts I always + + align:start position:0% +varies between 9 and 16 volts I always + + + align:start position:0% +varies between 9 and 16 volts I always +get my 5 Vols output + + align:start position:0% +get my 5 Vols output + + + align:start position:0% +get my 5 Vols output +Okay and like I said that's very + + align:start position:0% +Okay and like I said that's very + + + align:start position:0% +Okay and like I said that's very +common but what's the problem with this + + align:start position:0% +common but what's the problem with this + + + align:start position:0% +common but what's the problem with this +well there's a whole lot of problems + + align:start position:0% +well there's a whole lot of problems + + + align:start position:0% +well there's a whole lot of problems +with this right why why wouldn't you + + align:start position:0% +with this right why why wouldn't you + + + align:start position:0% +with this right why why wouldn't you +want to do this uh + + align:start position:0% +want to do this uh + + + align:start position:0% +want to do this uh +in typical + + align:start position:0% +in typical + + + align:start position:0% +in typical +operation efficiency terrible efficiency + + align:start position:0% +operation efficiency terrible efficiency + + + align:start position:0% +operation efficiency terrible efficiency +yes + + align:start position:0% +yes + + + align:start position:0% +yes +exactly so let's think about this if I + + align:start position:0% +exactly so let's think about this if I + + + align:start position:0% +exactly so let's think about this if I +accept the fact let me call this current + + align:start position:0% +accept the fact let me call this current + + + align:start position:0% +accept the fact let me call this current +I in + + align:start position:0% + + + + align:start position:0% + +okay and this current I + + align:start position:0% +okay and this current I + + + align:start position:0% +okay and this current I +out + + align:start position:0% +out + + + align:start position:0% +out +okay if this thing does act exactly like + + align:start position:0% +okay if this thing does act exactly like + + + align:start position:0% +okay if this thing does act exactly like +a variable resistor the input currents + + align:start position:0% +a variable resistor the input currents + + + align:start position:0% +a variable resistor the input currents +equal to the output current now this + + align:start position:0% +equal to the output current now this + + + align:start position:0% +equal to the output current now this +actually a real system might have some + + align:start position:0% +actually a real system might have some + + + align:start position:0% +actually a real system might have some +current that actually also goes to + + align:start position:0% +current that actually also goes to + + + align:start position:0% +current that actually also goes to +ground let's take the best case where + + align:start position:0% +ground let's take the best case where + + + align:start position:0% +ground let's take the best case where +the output current is equal to the input + + align:start position:0% +the output current is equal to the input + + + align:start position:0% +the output current is equal to the input +current okay what would be the + + align:start position:0% +current okay what would be the + + + align:start position:0% +current okay what would be the +efficiency of this Beast well the + + align:start position:0% + + + + align:start position:0% + +efficiency the efficiency is equal to + + align:start position:0% +efficiency the efficiency is equal to + + + align:start position:0% +efficiency the efficiency is equal to +the output power over the input power + + align:start position:0% +the output power over the input power + + + align:start position:0% +the output power over the input power +right I'm drawing energy maybe from my + + align:start position:0% +right I'm drawing energy maybe from my + + + align:start position:0% +right I'm drawing energy maybe from my +car battery or whatever my battery + + align:start position:0% +car battery or whatever my battery + + + align:start position:0% +car battery or whatever my battery +source is and I'm delivering it to the + + align:start position:0% +source is and I'm delivering it to the + + + align:start position:0% +source is and I'm delivering it to the +output but not all of it's getting to + + align:start position:0% +output but not all of it's getting to + + + align:start position:0% +output but not all of it's getting to +the output so the output power is V out + + align:start position:0% +the output so the output power is V out + + + align:start position:0% +the output so the output power is V out +time I + + align:start position:0% +time I + + + align:start position:0% +time I +out and my input power is VN time I in + + align:start position:0% +out and my input power is VN time I in + + + align:start position:0% +out and my input power is VN time I in +and I just told you that I out was equal + + align:start position:0% +and I just told you that I out was equal + + + align:start position:0% +and I just told you that I out was equal +to I in in the best case so that's V out + + align:start position:0% +to I in in the best case so that's V out + + + align:start position:0% +to I in in the best case so that's V out +over + + align:start position:0% +over + + + align:start position:0% +over +VN right so if I'm coming in from 15 + + align:start position:0% +VN right so if I'm coming in from 15 + + + align:start position:0% +VN right so if I'm coming in from 15 +volts and I'm getting five + + align:start position:0% +volts and I'm getting five + + + align:start position:0% +volts and I'm getting five +volts that's 33% efficiency right I've + + align:start position:0% +volts that's 33% efficiency right I've + + + align:start position:0% +volts that's 33% efficiency right I've +taken 2/3 of my energy and thrown it + + align:start position:0% +taken 2/3 of my energy and thrown it + + + align:start position:0% +taken 2/3 of my energy and thrown it +away + + align:start position:0% +away + + + align:start position:0% +away +now if I got lots of energy floating + + align:start position:0% +now if I got lots of energy floating + + + align:start position:0% +now if I got lots of energy floating +around and I'm processing a microwatt + + align:start position:0% +around and I'm processing a microwatt + + + align:start position:0% +around and I'm processing a microwatt +maybe maybe I don't care maybe I'll live + + align:start position:0% +maybe maybe I don't care maybe I'll live + + + align:start position:0% +maybe maybe I don't care maybe I'll live +with that because this thing's pretty + + align:start position:0% +with that because this thing's pretty + + + align:start position:0% +with that because this thing's pretty +simple right it's a transistor it's a + + align:start position:0% +simple right it's a transistor it's a + + + align:start position:0% +simple right it's a transistor it's a +power transistor and some controls and + + align:start position:0% +power transistor and some controls and + + + align:start position:0% +power transistor and some controls and +they can often put all that on one + + align:start position:0% +they can often put all that on one + + + align:start position:0% +they can often put all that on one +integrated circuit or even as a subblock + + align:start position:0% +integrated circuit or even as a subblock + + + align:start position:0% +integrated circuit or even as a subblock +on an integrated circuit I might still + + align:start position:0% +on an integrated circuit I might still + + + align:start position:0% +on an integrated circuit I might still +need some filtering it's not it's not + + align:start position:0% +need some filtering it's not it's not + + + align:start position:0% +need some filtering it's not it's not +quite as easy as it sounds but um pretty + + align:start position:0% +quite as easy as it sounds but um pretty + + + align:start position:0% +quite as easy as it sounds but um pretty +much it's relatively simple but my + + align:start position:0% +much it's relatively simple but my + + + align:start position:0% +much it's relatively simple but my +efficiency is miserable now if I thought + + align:start position:0% +efficiency is miserable now if I thought + + + align:start position:0% +efficiency is miserable now if I thought +about in your in your + + align:start position:0% +about in your in your + + + align:start position:0% +about in your in your +computer right your desktop computer + + align:start position:0% +computer right your desktop computer + + + align:start position:0% +computer right your desktop computer +typically the intermediate Supply that + + align:start position:0% +typically the intermediate Supply that + + + align:start position:0% +typically the intermediate Supply that +you're getting after it's sort of come + + align:start position:0% +you're getting after it's sort of come + + + align:start position:0% +you're getting after it's sort of come +in from the grid and been transformed + + align:start position:0% +in from the grid and been transformed + + + align:start position:0% +in from the grid and been transformed +down you get 12 volts right and let's + + align:start position:0% +down you get 12 volts right and let's + + + align:start position:0% +down you get 12 volts right and let's +say your computer is it sort of it + + align:start position:0% +say your computer is it sort of it + + + align:start position:0% +say your computer is it sort of it +depends on what it's doing but say it's + + align:start position:0% +depends on what it's doing but say it's + + + align:start position:0% +depends on what it's doing but say it's +operating at a volt right so then you're + + align:start position:0% +operating at a volt right so then you're + + + align:start position:0% +operating at a volt right so then you're +less than 10% efficient right and if you + + align:start position:0% +less than 10% efficient right and if you + + + align:start position:0% +less than 10% efficient right and if you +think that you know you can have a + + align:start position:0% +think that you know you can have a + + + align:start position:0% +think that you know you can have a +microprocessor that's taking 200 amps at + + align:start position:0% +microprocessor that's taking 200 amps at + + + align:start position:0% +microprocessor that's taking 200 amps at +a volt or few hundred Watts suddenly if + + align:start position:0% +a volt or few hundred Watts suddenly if + + + align:start position:0% +a volt or few hundred Watts suddenly if +I've got less than 10% efficiency on 200 + + align:start position:0% +I've got less than 10% efficiency on 200 + + + align:start position:0% +I've got less than 10% efficiency on 200 +Watts that means I need to put in a few + + align:start position:0% +Watts that means I need to put in a few + + + align:start position:0% +Watts that means I need to put in a few +kilowatts well you can't even plug that + + align:start position:0% +kilowatts well you can't even plug that + + + align:start position:0% +kilowatts well you can't even plug that +into the wall never mind the fact you've + + align:start position:0% +into the wall never mind the fact you've + + + align:start position:0% +into the wall never mind the fact you've +just made a massive room heater right + + align:start position:0% +just made a massive room heater right + + + align:start position:0% +just made a massive room heater right +that's that's like that'd be great for + + align:start position:0% +that's that's like that'd be great for + + + align:start position:0% +that's that's like that'd be great for +heating your dorm room um but pretty + + align:start position:0% +heating your dorm room um but pretty + + + align:start position:0% +heating your dorm room um but pretty +terrible for the overall system okay so + + align:start position:0% +terrible for the overall system okay so + + + align:start position:0% +terrible for the overall system okay so +the number one reason we don't like this + + align:start position:0% +the number one reason we don't like this + + + align:start position:0% +the number one reason we don't like this +solution is + + align:start position:0% +solution is + + + align:start position:0% +solution is +efficiency good thing it's simple bad + + align:start position:0% +efficiency good thing it's simple bad + + + align:start position:0% +efficiency good thing it's simple bad +thing it's terrible efficiency this + + align:start position:0% +thing it's terrible efficiency this + + + align:start position:0% +thing it's terrible efficiency this +technique I should have noted + + align:start position:0% + + + + align:start position:0% + +is what's known for historical reasons + + align:start position:0% +is what's known for historical reasons + + + align:start position:0% +is what's known for historical reasons +as a quote unquote + + align:start position:0% +as a quote unquote + + + align:start position:0% +as a quote unquote +linear power + + align:start position:0% +linear power + + + align:start position:0% +linear power +supply why linear I think only because + + align:start position:0% +supply why linear I think only because + + + align:start position:0% +supply why linear I think only because +analog circuits kind of a category of + + align:start position:0% +analog circuits kind of a category of + + + align:start position:0% +analog circuits kind of a category of +them became known as quote unquote + + align:start position:0% +them became known as quote unquote + + + align:start position:0% +them became known as quote unquote +linear circuits there's nothing really + + align:start position:0% +linear circuits there's nothing really + + + align:start position:0% +linear circuits there's nothing really +that linear about it but this would be + + align:start position:0% +that linear about it but this would be + + + align:start position:0% +that linear about it but this would be +called a linear power converter or or + + align:start position:0% +called a linear power converter or or + + + align:start position:0% +called a linear power converter or or +some sometimes a linear regulator is + + align:start position:0% +some sometimes a linear regulator is + + + align:start position:0% +some sometimes a linear regulator is +what it would be called + + align:start position:0% +what it would be called + + + align:start position:0% +what it would be called +okay for obvious reasons I hate throwing + + align:start position:0% +okay for obvious reasons I hate throwing + + + align:start position:0% +okay for obvious reasons I hate throwing +away energy we're not going to talk + + align:start position:0% +away energy we're not going to talk + + + align:start position:0% +away energy we're not going to talk +about linear Regulators at all in this + + align:start position:0% +about linear Regulators at all in this + + + align:start position:0% +about linear Regulators at all in this +class and there's plenty of classes + + align:start position:0% +class and there's plenty of classes + + + align:start position:0% +class and there's plenty of classes +where you can learn about that we want + + align:start position:0% +where you can learn about that we want + + + align:start position:0% +where you can learn about that we want +to do things some better way that's not + + align:start position:0% +to do things some better way that's not + + + align:start position:0% +to do things some better way that's not +going to burn lots of energy okay so + + align:start position:0% +going to burn lots of energy okay so + + + align:start position:0% +going to burn lots of energy okay so +ideally you know in my world the goal is + + align:start position:0% +ideally you know in my world the goal is + + + align:start position:0% +ideally you know in my world the goal is +to take as much of the input energy in + + align:start position:0% +to take as much of the input energy in + + + align:start position:0% +to take as much of the input energy in +and put it to the output right and + + align:start position:0% +and put it to the output right and + + + align:start position:0% +and put it to the output right and +that's important because think about it + + align:start position:0% +that's important because think about it + + + align:start position:0% +that's important because think about it +this way I I showed you a photo graph of + + align:start position:0% +this way I I showed you a photo graph of + + + align:start position:0% +this way I I showed you a photo graph of +something that was you know really tiny + + align:start position:0% +something that was you know really tiny + + + align:start position:0% +something that was you know really tiny +maybe that big right and that thick and + + align:start position:0% +maybe that big right and that thick and + + + align:start position:0% +maybe that big right and that thick and +was processing a kilowatt right if I + + align:start position:0% +was processing a kilowatt right if I + + + align:start position:0% +was processing a kilowatt right if I +don't do that at really high efficiency + + align:start position:0% +don't do that at really high efficiency + + + align:start position:0% +don't do that at really high efficiency +that thing will burn up right so in + + align:start position:0% +that thing will burn up right so in + + + align:start position:0% +that thing will burn up right so in +order to make something small I need to + + align:start position:0% +order to make something small I need to + + + align:start position:0% +order to make something small I need to +make it efficient all right so we want + + align:start position:0% +make it efficient all right so we want + + + align:start position:0% +make it efficient all right so we want +almost all of the energy at the input to + + align:start position:0% +almost all of the energy at the input to + + + align:start position:0% +almost all of the energy at the input to +get to the output well how can we do + + align:start position:0% +get to the output well how can we do + + + align:start position:0% +get to the output well how can we do +that let's think of a completely + + align:start position:0% +that let's think of a completely + + + align:start position:0% +that let's think of a completely +different way we might achieve this same + + align:start position:0% +different way we might achieve this same + + + align:start position:0% +different way we might achieve this same +function function all right and here's + + align:start position:0% +function function all right and here's + + + align:start position:0% +function function all right and here's +the idea here's my + + align:start position:0% + + + + align:start position:0% + +input I'm going to create a switch here + + align:start position:0% +input I'm going to create a switch here + + + align:start position:0% +input I'm going to create a switch here +single pole double throw switch now + + align:start position:0% +single pole double throw switch now + + + align:start position:0% +single pole double throw switch now +we're not going to go get physical + + align:start position:0% +we're not going to go get physical + + + align:start position:0% +we're not going to go get physical +switches we're probably going to get + + align:start position:0% +switches we're probably going to get + + + align:start position:0% +switches we're probably going to get +semiconductor devices and make it do + + align:start position:0% +semiconductor devices and make it do + + + align:start position:0% +semiconductor devices and make it do +something like this but we could use + + align:start position:0% +something like this but we could use + + + align:start position:0% +something like this but we could use +anything any technology that was + + align:start position:0% +anything any technology that was + + + align:start position:0% +anything any technology that was +practical as a switch okay and let me + + align:start position:0% +practical as a switch okay and let me + + + align:start position:0% +practical as a switch okay and let me +just Define if I'm going to define a + + align:start position:0% +just Define if I'm going to define a + + + align:start position:0% +just Define if I'm going to define a +switching function that I'm going to + + align:start position:0% +switching function that I'm going to + + + align:start position:0% +switching function that I'm going to +call Q of T if Q of T is + + align:start position:0% +call Q of T if Q of T is + + + align:start position:0% +call Q of T if Q of T is +one I'll connect the switch to the input + + align:start position:0% +one I'll connect the switch to the input + + + align:start position:0% +one I'll connect the switch to the input +if Q of T is + + align:start position:0% + + + + align:start position:0% + +zero I'll connect the switch to the + + align:start position:0% +zero I'll connect the switch to the + + + align:start position:0% +zero I'll connect the switch to the +ground okay so this notion this voltage + + align:start position:0% +ground okay so this notion this voltage + + + align:start position:0% +ground okay so this notion this voltage +okay maybe I'll call this voltage + + align:start position:0% + + + + align:start position:0% + +VX all right so one thing I could do is + + align:start position:0% +VX all right so one thing I could do is + + + align:start position:0% +VX all right so one thing I could do is +I could say okay let me just hook this + + align:start position:0% +I could say okay let me just hook this + + + align:start position:0% +I could say okay let me just hook this +up to my load here's my resistive + + align:start position:0% +up to my load here's my resistive + + + align:start position:0% +up to my load here's my resistive +load whatever it is and I'll call this V + + align:start position:0% +load whatever it is and I'll call this V + + + align:start position:0% +load whatever it is and I'll call this V +out all right well all right what would + + align:start position:0% +out all right well all right what would + + + align:start position:0% +out all right well all right what would +that look like well let me Define my + + align:start position:0% +that look like well let me Define my + + + align:start position:0% +that look like well let me Define my +switching + + align:start position:0% + + + + align:start position:0% + +function I'm going to put the switch in + + align:start position:0% +function I'm going to put the switch in + + + align:start position:0% +function I'm going to put the switch in +the up position for a little while then + + align:start position:0% +the up position for a little while then + + + align:start position:0% +the up position for a little while then +I'll put it in the down + + align:start position:0% +I'll put it in the down + + + align:start position:0% +I'll put it in the down +position by setting the switching + + align:start position:0% +position by setting the switching + + + align:start position:0% +position by setting the switching +function to zero and then I'll just + + align:start position:0% +function to zero and then I'll just + + + align:start position:0% +function to zero and then I'll just +repeat that so I said we're going to + + align:start position:0% +repeat that so I said we're going to + + + align:start position:0% +repeat that so I said we're going to +operate in some kind of repetitive + + align:start position:0% +operate in some kind of repetitive + + + align:start position:0% +operate in some kind of repetitive +fashion here and so + + align:start position:0% +fashion here and so + + + align:start position:0% +fashion here and so +forth let me operate with some period + + align:start position:0% +forth let me operate with some period + + + align:start position:0% +forth let me operate with some period +T okay that's mean my switching period + + align:start position:0% +T okay that's mean my switching period + + + align:start position:0% +T okay that's mean my switching period +in this example I'm showing you is a + + align:start position:0% +in this example I'm showing you is a + + + align:start position:0% +in this example I'm showing you is a +fixed switching period okay and I will + + align:start position:0% +fixed switching period okay and I will + + + align:start position:0% +fixed switching period okay and I will +keep the switch in the up position some + + align:start position:0% +keep the switch in the up position some + + + align:start position:0% +keep the switch in the up position some +fraction of the time that I'll call DT + + align:start position:0% +fraction of the time that I'll call DT + + + align:start position:0% +fraction of the time that I'll call DT +so D is a fraction zero is less than D + + align:start position:0% +so D is a fraction zero is less than D + + + align:start position:0% +so D is a fraction zero is less than D +is less than + + align:start position:0% + + + + align:start position:0% + +one + + align:start position:0% +one + + + align:start position:0% +one +okay so if I do that then what do I get + + align:start position:0% +okay so if I do that then what do I get + + + align:start position:0% +okay so if I do that then what do I get +for VX VX is going to look something + + align:start position:0% +for VX VX is going to look something + + + align:start position:0% +for VX VX is going to look something +like + + align:start position:0% +like + + + align:start position:0% +like +this okay um when the switch is in the + + align:start position:0% +this okay um when the switch is in the + + + align:start position:0% +this okay um when the switch is in the +up position VX equals + + align:start position:0% + + + + align:start position:0% + +VN so this is VX when the switch is in + + align:start position:0% +VN so this is VX when the switch is in + + + align:start position:0% +VN so this is VX when the switch is in +the down position VX is equal to zero + + align:start position:0% + + + + align:start position:0% + +okay and I rinse and repeat and I get + + align:start position:0% +okay and I rinse and repeat and I get + + + align:start position:0% +okay and I rinse and repeat and I get +this now now I have this pulsating + + align:start position:0% +this now now I have this pulsating + + + align:start position:0% +this now now I have this pulsating +voltage VX okay what's the average value + + align:start position:0% +voltage VX okay what's the average value + + + align:start position:0% +voltage VX okay what's the average value +of that voltage + + align:start position:0% +of that voltage + + + align:start position:0% +of that voltage +VX right I can take you know simple + + align:start position:0% +VX right I can take you know simple + + + align:start position:0% +VX right I can take you know simple +integration right one over T the + + align:start position:0% +integration right one over T the + + + align:start position:0% +integration right one over T the +integral of VX of T over a period + + align:start position:0% +integral of VX of T over a period + + + align:start position:0% +integral of VX of T over a period +T okay and what I would + + align:start position:0% +T okay and what I would + + + align:start position:0% +T okay and what I would +find is the average voltage of VX + + align:start position:0% +find is the average voltage of VX + + + align:start position:0% +find is the average voltage of VX +is equal to D * + + align:start position:0% +is equal to D * + + + align:start position:0% +is equal to D * +VN all right so I can create a waveform + + align:start position:0% +VN all right so I can create a waveform + + + align:start position:0% +VN all right so I can create a waveform +here whose average value is something + + align:start position:0% +here whose average value is something + + + align:start position:0% +here whose average value is something +different than VN just by controlling + + align:start position:0% +different than VN just by controlling + + + align:start position:0% +different than VN just by controlling +this timing + + align:start position:0% +this timing + + + align:start position:0% +this timing +D all right so now if my load resistor + + align:start position:0% +D all right so now if my load resistor + + + align:start position:0% +D all right so now if my load resistor +here was a space heater you know maybe + + align:start position:0% +here was a space heater you know maybe + + + align:start position:0% +here was a space heater you know maybe +this is some load resistance RL and I + + align:start position:0% +this is some load resistance RL and I + + + align:start position:0% +this is some load resistance RL and I +wanted to modulate the power to that + + align:start position:0% +wanted to modulate the power to that + + + align:start position:0% +wanted to modulate the power to that +load resistance by controlling the + + align:start position:0% +load resistance by controlling the + + + align:start position:0% +load resistance by controlling the +average voltage on the load resistance + + align:start position:0% +average voltage on the load resistance + + + align:start position:0% +average voltage on the load resistance +then this technique would work + + align:start position:0% +then this technique would work + + + align:start position:0% +then this technique would work +great if on the other hand my load was a + + align:start position:0% +great if on the other hand my load was a + + + align:start position:0% +great if on the other hand my load was a +microprocessor and I start you know + + align:start position:0% +microprocessor and I start you know + + + align:start position:0% +microprocessor and I start you know +pulsing 12 volts between 12 volts and + + align:start position:0% +pulsing 12 volts between 12 volts and + + + align:start position:0% +pulsing 12 volts between 12 volts and +zero on it I'm probably going to blow it + + align:start position:0% +zero on it I'm probably going to blow it + + + align:start position:0% +zero on it I'm probably going to blow it +up right so that's no good all right but + + align:start position:0% +up right so that's no good all right but + + + align:start position:0% +up right so that's no good all right but +this notion is at least that I can + + align:start position:0% +this notion is at least that I can + + + align:start position:0% +this notion is at least that I can +control an average voltage by pulsing a + + align:start position:0% +control an average voltage by pulsing a + + + align:start position:0% +control an average voltage by pulsing a +set a switch okay and this would be + + align:start position:0% +set a switch okay and this would be + + + align:start position:0% +set a switch okay and this would be +known as pwm or pulse width modulation + + align:start position:0% +known as pwm or pulse width modulation + + + align:start position:0% +known as pwm or pulse width modulation +because I control the average volage by + + align:start position:0% +because I control the average volage by + + + align:start position:0% +because I control the average volage by +the fraction of the time the switch is + + align:start position:0% +the fraction of the time the switch is + + + align:start position:0% +the fraction of the time the switch is +in one position versus the + + align:start position:0% +in one position versus the + + + align:start position:0% +in one position versus the +other okay so that's that's the basic + + align:start position:0% +other okay so that's that's the basic + + + align:start position:0% +other okay so that's that's the basic +concept we're going to be using how do I + + align:start position:0% +concept we're going to be using how do I + + + align:start position:0% +concept we're going to be using how do I +fix this + + align:start position:0% +fix this + + + align:start position:0% +fix this +little problem of in practice right what + + align:start position:0% +little problem of in practice right what + + + align:start position:0% +little problem of in practice right what +I wanted was a DC voltage what I got was + + align:start position:0% +I wanted was a DC voltage what I got was + + + align:start position:0% +I wanted was a DC voltage what I got was +a pulsating voltage that just happened + + align:start position:0% +a pulsating voltage that just happened + + + align:start position:0% +a pulsating voltage that just happened +to have the right average value well I + + align:start position:0% +to have the right average value well I + + + align:start position:0% +to have the right average value well I +could go do something like this maybe + + align:start position:0% +could go do something like this maybe + + + align:start position:0% +could go do something like this maybe +I'll go back and say okay let me throw + + align:start position:0% +I'll go back and say okay let me throw + + + align:start position:0% +I'll go back and say okay let me throw +in a + + align:start position:0% +in a + + + align:start position:0% +in a +filter and extract out the component I + + align:start position:0% +filter and extract out the component I + + + align:start position:0% +filter and extract out the component I +want right I want the average value of + + align:start position:0% +want right I want the average value of + + + align:start position:0% +want right I want the average value of +VX so maybe I'll come back here and say + + align:start position:0% +VX so maybe I'll come back here and say + + + align:start position:0% +VX so maybe I'll come back here and say +okay let me throw in a filter and I'll + + align:start position:0% +okay let me throw in a filter and I'll + + + align:start position:0% +okay let me throw in a filter and I'll +use an inductor + + align:start position:0% + + + + align:start position:0% + +here an l and if I want optionally I can + + align:start position:0% +here an l and if I want optionally I can + + + align:start position:0% +here an l and if I want optionally I can +put a capacitor here + + align:start position:0% +put a capacitor here + + + align:start position:0% +put a capacitor here +C okay and you know I think people can + + align:start position:0% +C okay and you know I think people can + + + align:start position:0% +C okay and you know I think people can +look at + + align:start position:0% +look at + + + align:start position:0% +look at +this filter block and recognize that as + + align:start position:0% +this filter block and recognize that as + + + align:start position:0% +this filter block and recognize that as +a low pass filter the DC component of VX + + align:start position:0% +a low pass filter the DC component of VX + + + align:start position:0% +a low pass filter the DC component of VX +passes through the filter to the + + align:start position:0% +passes through the filter to the + + + align:start position:0% +passes through the filter to the +output and the AC component of VX gets + + align:start position:0% +output and the AC component of VX gets + + + align:start position:0% +output and the AC component of VX gets +rejected by the filter and doesn't get + + align:start position:0% +rejected by the filter and doesn't get + + + align:start position:0% +rejected by the filter and doesn't get +to the output so in this case I might + + align:start position:0% +to the output so in this case I might + + + align:start position:0% +to the output so in this case I might +get an output voltage V out that looks + + align:start position:0% +get an output voltage V out that looks + + + align:start position:0% +get an output voltage V out that looks +something like this I'm going to sort of + + align:start position:0% +something like this I'm going to sort of + + + align:start position:0% +something like this I'm going to sort of +make this up but you know I'm amplifying + + align:start position:0% +make this up but you know I'm amplifying + + + align:start position:0% +make this up but you know I'm amplifying +the Ripple but eventually it's going to + + align:start position:0% +the Ripple but eventually it's going to + + + align:start position:0% +the Ripple but eventually it's going to +filter + + align:start position:0% +filter + + + align:start position:0% +filter +the energy content of that and the + + align:start position:0% +the energy content of that and the + + + align:start position:0% +the energy content of that and the +fundamental and higher harmonic terms of + + align:start position:0% +fundamental and higher harmonic terms of + + + align:start position:0% +fundamental and higher harmonic terms of +VX are going to go away and the DC terms + + align:start position:0% +VX are going to go away and the DC terms + + + align:start position:0% +VX are going to go away and the DC terms +going to go through and I get an output + + align:start position:0% +going to go through and I get an output + + + align:start position:0% +going to go through and I get an output +voltage V out that's very close to + + align:start position:0% +voltage V out that's very close to + + + align:start position:0% +voltage V out that's very close to +whatever value I want and if I'm + + align:start position:0% +whatever value I want and if I'm + + + align:start position:0% +whatever value I want and if I'm +basically make the filter cut off hard + + align:start position:0% +basically make the filter cut off hard + + + align:start position:0% +basically make the filter cut off hard +enough I can't distinguish between V out + + align:start position:0% +enough I can't distinguish between V out + + + align:start position:0% +enough I can't distinguish between V out +and the average value of VX and I get + + align:start position:0% +and the average value of VX and I get + + + align:start position:0% +and the average value of VX and I get +exactly what I wanted Okay so we've + + align:start position:0% +exactly what I wanted Okay so we've + + + align:start position:0% +exactly what I wanted Okay so we've +essentially now created + + align:start position:0% + + + + align:start position:0% + +a voltage + + align:start position:0% + + + + align:start position:0% + +converter that lets me use this + + align:start position:0% +converter that lets me use this + + + align:start position:0% +converter that lets me use this +pulsewidth modulation by controlling + + align:start position:0% +pulsewidth modulation by controlling + + + align:start position:0% +pulsewidth modulation by controlling +this duty cycle D to regulate the output + + align:start position:0% +this duty cycle D to regulate the output + + + align:start position:0% +this duty cycle D to regulate the output +just the way I wanted so instead of you + + align:start position:0% +just the way I wanted so instead of you + + + align:start position:0% +just the way I wanted so instead of you +know here I'm just changing the gate + + align:start position:0% +know here I'm just changing the gate + + + align:start position:0% +know here I'm just changing the gate +voltage on my transistor to control the + + align:start position:0% +voltage on my transistor to control the + + + align:start position:0% +voltage on my transistor to control the +output here I'm changing timing I'm + + align:start position:0% +output here I'm changing timing I'm + + + align:start position:0% +output here I'm changing timing I'm +going to control + + align:start position:0% +going to control + + + align:start position:0% +going to control +timing okay and by controlling timing I + + align:start position:0% +timing okay and by controlling timing I + + + align:start position:0% +timing okay and by controlling timing I +control average value and then I get + + align:start position:0% +control average value and then I get + + + align:start position:0% +control average value and then I get +what I want right any questions about + + align:start position:0% +what I want right any questions about + + + align:start position:0% +what I want right any questions about +that what's what's the + + align:start position:0% +that what's what's the + + + align:start position:0% +that what's what's the +efficiency that is an excellent question + + align:start position:0% +efficiency that is an excellent question + + + align:start position:0% +efficiency that is an excellent question +the answer is + + align:start position:0% + + + + align:start position:0% + +um ideally theoretically the efficiency + + align:start position:0% +um ideally theoretically the efficiency + + + align:start position:0% +um ideally theoretically the efficiency +can be + + align:start position:0% +can be + + + align:start position:0% +can be +100% in reality it can't be why do I say + + align:start position:0% +100% in reality it can't be why do I say + + + align:start position:0% +100% in reality it can't be why do I say +the efficiency can ideally be + + align:start position:0% +the efficiency can ideally be + + + align:start position:0% +the efficiency can ideally be +100% well how would I implement + + align:start position:0% +100% well how would I implement + + + align:start position:0% +100% well how would I implement +this box in the real world usually I I + + align:start position:0% +this box in the real world usually I I + + + align:start position:0% +this box in the real world usually I I +don't get semiconductor single pole + + align:start position:0% +don't get semiconductor single pole + + + align:start position:0% +don't get semiconductor single pole +double throw switches the way I would + + align:start position:0% +double throw switches the way I would + + + align:start position:0% +double throw switches the way I would +usually build this Beast is like + + align:start position:0% +usually build this Beast is like + + + align:start position:0% +usually build this Beast is like +this okay I would usually have a first + + align:start position:0% +this okay I would usually have a first + + + align:start position:0% +this okay I would usually have a first +switch and a second switch implemented + + align:start position:0% +switch and a second switch implemented + + + align:start position:0% +switch and a second switch implemented +like this so I close this when Q of T is + + align:start position:0% +like this so I close this when Q of T is + + + align:start position:0% +like this so I close this when Q of T is +equal to + + align:start position:0% +equal to + + + align:start position:0% +equal to +one and I close this one when Q of T is + + align:start position:0% +one and I close this one when Q of T is + + + align:start position:0% +one and I close this one when Q of T is +equal to + + align:start position:0% +equal to + + + align:start position:0% +equal to +zero okay and then I build my filter + + align:start position:0% + + + + align:start position:0% + +and then I put my load on here okay + + align:start position:0% +and then I put my load on here okay + + + align:start position:0% +and then I put my load on here okay +so what would be the efficiency of this + + align:start position:0% +so what would be the efficiency of this + + + align:start position:0% +so what would be the efficiency of this +thing well let's think about + + align:start position:0% +thing well let's think about + + + align:start position:0% +thing well let's think about +this um this is voltage Vex and this is + + align:start position:0% +this um this is voltage Vex and this is + + + align:start position:0% +this um this is voltage Vex and this is +voltage + + align:start position:0% + + + + align:start position:0% + +vout all + + align:start position:0% + + + + align:start position:0% + +right what power is theoretically + + align:start position:0% +right what power is theoretically + + + align:start position:0% +right what power is theoretically +dissipated in my switch if I have an + + align:start position:0% +dissipated in my switch if I have an + + + align:start position:0% +dissipated in my switch if I have an +ideal switch has zero resistance when + + align:start position:0% +ideal switch has zero resistance when + + + align:start position:0% +ideal switch has zero resistance when +it's on and has infinite resistance when + + align:start position:0% +it's on and has infinite resistance when + + + align:start position:0% +it's on and has infinite resistance when +it's + + align:start position:0% +it's + + + align:start position:0% +it's +off what's that zero power why because + + align:start position:0% +off what's that zero power why because + + + align:start position:0% +off what's that zero power why because +the power dissipated the power that goes + + align:start position:0% +the power dissipated the power that goes + + + align:start position:0% +the power dissipated the power that goes +into this box let me call this V + + align:start position:0% +into this box let me call this V + + + align:start position:0% +into this box let me call this V +switch let me call this I switch okay + + align:start position:0% +switch let me call this I switch okay + + + align:start position:0% +switch let me call this I switch okay +well P switch the power going into the + + align:start position:0% +well P switch the power going into the + + + align:start position:0% +well P switch the power going into the +switch the power being dissipated in the + + align:start position:0% +switch the power being dissipated in the + + + align:start position:0% +switch the power being dissipated in the +switch is going to be V switch time I + + align:start position:0% +switch is going to be V switch time I + + + align:start position:0% +switch is going to be V switch time I +switch + + align:start position:0% +switch + + + align:start position:0% +switch +okay well if it's an ideal switch then + + align:start position:0% +okay well if it's an ideal switch then + + + align:start position:0% +okay well if it's an ideal switch then +if the switch is on V switch is + + align:start position:0% +if the switch is on V switch is + + + align:start position:0% +if the switch is on V switch is +zero right it's ideal so it has no + + align:start position:0% +zero right it's ideal so it has no + + + align:start position:0% +zero right it's ideal so it has no +voltage drop when it's on so the power + + align:start position:0% +voltage drop when it's on so the power + + + align:start position:0% +voltage drop when it's on so the power +when it's on is + + align:start position:0% +when it's on is + + + align:start position:0% +when it's on is +zero when the switch is off it has + + align:start position:0% +zero when the switch is off it has + + + align:start position:0% +zero when the switch is off it has +infinite resistance so the switch is + + align:start position:0% +infinite resistance so the switch is + + + align:start position:0% +infinite resistance so the switch is +current zero so basically the power + + align:start position:0% +current zero so basically the power + + + align:start position:0% +current zero so basically the power +going into the switch if it's an ideal + + align:start position:0% +going into the switch if it's an ideal + + + align:start position:0% +going into the switch if it's an ideal +switch + + align:start position:0% +switch + + + align:start position:0% +switch +um is ideally zero so these these + + align:start position:0% +um is ideally zero so these these + + + align:start position:0% +um is ideally zero so these these +elements this ideal switch is a lossless + + align:start position:0% +elements this ideal switch is a lossless + + + align:start position:0% +elements this ideal switch is a lossless +element + + align:start position:0% +element + + + align:start position:0% +element +right + + align:start position:0% +right + + + align:start position:0% +right +likewise I wasn't I didn't just randomly + + align:start position:0% +likewise I wasn't I didn't just randomly + + + align:start position:0% +likewise I wasn't I didn't just randomly +choose any filter here right I chose an + + align:start position:0% +choose any filter here right I chose an + + + align:start position:0% +choose any filter here right I chose an +LC filter why did I choose an LC filter + + align:start position:0% +LC filter why did I choose an LC filter + + + align:start position:0% +LC filter why did I choose an LC filter +I choose an LC filter because inductors + + align:start position:0% +I choose an LC filter because inductors + + + align:start position:0% +I choose an LC filter because inductors +and capacitors are energy storage + + align:start position:0% +and capacitors are energy storage + + + align:start position:0% +and capacitors are energy storage +elements if they're ideal then they + + align:start position:0% +elements if they're ideal then they + + + align:start position:0% +elements if they're ideal then they +store energy but they don't dissipate + + align:start position:0% +store energy but they don't dissipate + + + align:start position:0% +store energy but they don't dissipate +energy right so basically + + align:start position:0% +energy right so basically + + + align:start position:0% +energy right so basically +everything in the box here everything + + align:start position:0% +everything in the box here everything + + + align:start position:0% +everything in the box here everything +between the input and the output is a + + align:start position:0% +between the input and the output is a + + + align:start position:0% +between the input and the output is a +lossless element so then one would + + align:start position:0% +lossless element so then one would + + + align:start position:0% +lossless element so then one would +assume that if every element's lossless + + align:start position:0% +assume that if every element's lossless + + + align:start position:0% +assume that if every element's lossless +any energy walking in to the left comes + + align:start position:0% +any energy walking in to the left comes + + + align:start position:0% +any energy walking in to the left comes +out to the right right and that's how + + align:start position:0% +out to the right right and that's how + + + align:start position:0% +out to the right right and that's how +that that kilowatt little 400 volt to + + align:start position:0% +that that kilowatt little 400 volt to + + + align:start position:0% +that that kilowatt little 400 volt to +12vt converter I showed you um in the + + align:start position:0% +12vt converter I showed you um in the + + + align:start position:0% +12vt converter I showed you um in the +photo is about 97% efficient it's not + + align:start position:0% +photo is about 97% efficient it's not + + + align:start position:0% +photo is about 97% efficient it's not +100% because you know the wires have + + align:start position:0% +100% because you know the wires have + + + align:start position:0% +100% because you know the wires have +some resistance and the switches have + + align:start position:0% +some resistance and the switches have + + + align:start position:0% +some resistance and the switches have +some on-state resistance a whole bunch + + align:start position:0% +some on-state resistance a whole bunch + + + align:start position:0% +some on-state resistance a whole bunch +of things that contribute to loss and + + align:start position:0% +of things that contribute to loss and + + + align:start position:0% +of things that contribute to loss and +we'll talk about that um but I can make + + align:start position:0% +we'll talk about that um but I can make + + + align:start position:0% +we'll talk about that um but I can make +it really close to 100% even though I + + align:start position:0% +it really close to 100% even though I + + + align:start position:0% +it really close to 100% even though I +might be doing a huge step down right so + + align:start position:0% +might be doing a huge step down right so + + + align:start position:0% +might be doing a huge step down right so +if I tried to build a linear regulator + + align:start position:0% +if I tried to build a linear regulator + + + align:start position:0% +if I tried to build a linear regulator +that was going from 400 to 12 volts + + align:start position:0% +that was going from 400 to 12 volts + + + align:start position:0% +that was going from 400 to 12 volts +that' be about 2 and a half% efficient + + align:start position:0% +that' be about 2 and a half% efficient + + + align:start position:0% +that' be about 2 and a half% efficient +right so if I want to generate a + + align:start position:0% +right so if I want to generate a + + + align:start position:0% +right so if I want to generate a +kilowatt at 2 and a half% efficiency + + align:start position:0% +kilowatt at 2 and a half% efficiency + + + align:start position:0% +kilowatt at 2 and a half% efficiency +what is that 40 kilowatt input and + + align:start position:0% +what is that 40 kilowatt input and + + + align:start position:0% +what is that 40 kilowatt input and +instead what I get is sort of like 1.03 + + align:start position:0% +instead what I get is sort of like 1.03 + + + align:start position:0% +instead what I get is sort of like 1.03 +kilowatt input to generate a kilowatt + + align:start position:0% +kilowatt input to generate a kilowatt + + + align:start position:0% +kilowatt input to generate a kilowatt +output right + + align:start position:0% +output right + + + align:start position:0% +output right +so the whole Magic that we're going to + + align:start position:0% +so the whole Magic that we're going to + + + align:start position:0% +so the whole Magic that we're going to +talk about this term is how can I use + + align:start position:0% +talk about this term is how can I use + + + align:start position:0% +talk about this term is how can I use +sort of perfectly lossless elements draw + + align:start position:0% +sort of perfectly lossless elements draw + + + align:start position:0% +sort of perfectly lossless elements draw +energy in process it and put it out the + + align:start position:0% +energy in process it and put it out the + + + align:start position:0% +energy in process it and put it out the +other side okay and by the way I should + + align:start position:0% +other side okay and by the way I should + + + align:start position:0% +other side okay and by the way I should +say not only did I say oh inductors and + + align:start position:0% +say not only did I say oh inductors and + + + align:start position:0% +say not only did I say oh inductors and +capacitors are lossless in principle + + align:start position:0% +capacitors are lossless in principle + + + align:start position:0% +capacitors are lossless in principle +lossless elements uh it wasn't an + + align:start position:0% +lossless elements uh it wasn't an + + + align:start position:0% +lossless elements uh it wasn't an +accident that we put an inductor + + align:start position:0% +accident that we put an inductor + + + align:start position:0% +accident that we put an inductor +here right because think about it when + + align:start position:0% +here right because think about it when + + + align:start position:0% +here right because think about it when +this switch is + + align:start position:0% +this switch is + + + align:start position:0% +this switch is +closed right I have V in on this side of + + align:start position:0% +closed right I have V in on this side of + + + align:start position:0% +closed right I have V in on this side of +the inductor and V out on this side of + + align:start position:0% +the inductor and V out on this side of + + + align:start position:0% +the inductor and V out on this side of +the inductor and I have current flowing + + align:start position:0% +the inductor and I have current flowing + + + align:start position:0% +the inductor and I have current flowing +this way right well what's happening + + align:start position:0% +this way right well what's happening + + + align:start position:0% +this way right well what's happening +when this switch is closed basically + + align:start position:0% +when this switch is closed basically + + + align:start position:0% +when this switch is closed basically +there's voltage across this inductor and + + align:start position:0% +there's voltage across this inductor and + + + align:start position:0% +there's voltage across this inductor and +current going through it we are storing + + align:start position:0% +current going through it we are storing + + + align:start position:0% +current going through it we are storing +energy in that inductor so the + + align:start position:0% +energy in that inductor so the + + + align:start position:0% +energy in that inductor so the +difference in voltage between the input + + align:start position:0% +difference in voltage between the input + + + align:start position:0% +difference in voltage between the input +and the output is basically putting + + align:start position:0% +and the output is basically putting + + + align:start position:0% +and the output is basically putting +energy in the + + align:start position:0% +energy in the + + + align:start position:0% +energy in the +inductor in this the other part of the + + align:start position:0% +inductor in this the other part of the + + + align:start position:0% +inductor in this the other part of the +cycle + + align:start position:0% +cycle + + + align:start position:0% +cycle +when I turn this switch off and this + + align:start position:0% +when I turn this switch off and this + + + align:start position:0% +when I turn this switch off and this +switch + + align:start position:0% +switch + + + align:start position:0% +switch +on basically I'm taking now I have a + + align:start position:0% +on basically I'm taking now I have a + + + align:start position:0% +on basically I'm taking now I have a +negative voltage across the inductor I'm + + align:start position:0% +negative voltage across the inductor I'm + + + align:start position:0% +negative voltage across the inductor I'm +taking energy out of the inductor and + + align:start position:0% +taking energy out of the inductor and + + + align:start position:0% +taking energy out of the inductor and +put it in the output so essentially I'm + + align:start position:0% +put it in the output so essentially I'm + + + align:start position:0% +put it in the output so essentially I'm +using this inductor as a filter but it's + + align:start position:0% +using this inductor as a filter but it's + + + align:start position:0% +using this inductor as a filter but it's +also an intermediate store of energy + + align:start position:0% +also an intermediate store of energy + + + align:start position:0% +also an intermediate store of energy +that lets me kind of take energy from + + align:start position:0% +that lets me kind of take energy from + + + align:start position:0% +that lets me kind of take energy from +the input and transfer to the output + + align:start position:0% +the input and transfer to the output + + + align:start position:0% +the input and transfer to the output +with a voltage conversion without losing + + align:start position:0% +with a voltage conversion without losing + + + align:start position:0% +with a voltage conversion without losing +any of the + + align:start position:0% +any of the + + + align:start position:0% +any of the +energy excellent question long answer to + + align:start position:0% +energy excellent question long answer to + + + align:start position:0% +energy excellent question long answer to +a short question any other + + align:start position:0% + + + + align:start position:0% + +questions okay so as I said um my goal + + align:start position:0% +questions okay so as I said um my goal + + + align:start position:0% +questions okay so as I said um my goal +is to sort of first of all teach you a + + align:start position:0% +is to sort of first of all teach you a + + + align:start position:0% +is to sort of first of all teach you a +lot of the underlying principles this is + + align:start position:0% +lot of the underlying principles this is + + + align:start position:0% +lot of the underlying principles this is +the this is the world's if you will + + align:start position:0% +the this is the world's if you will + + + align:start position:0% +the this is the world's if you will +simplest switching power converter so + + align:start position:0% +simplest switching power converter so + + + align:start position:0% +simplest switching power converter so +the when we use this technique we also + + align:start position:0% +the when we use this technique we also + + + align:start position:0% +the when we use this technique we also +often say we're switched + + align:start position:0% + + + + align:start position:0% + +mode all right with the notion that + + align:start position:0% +mode all right with the notion that + + + align:start position:0% +mode all right with the notion that +we're going to use + + align:start position:0% +we're going to use + + + align:start position:0% +we're going to use +switches and energy storage elements to + + align:start position:0% +switches and energy storage elements to + + + align:start position:0% +switches and energy storage elements to +process energy and that's sort of what + + align:start position:0% +process energy and that's sort of what + + + align:start position:0% +process energy and that's sort of what +sits at the core of Power + + align:start position:0% +sits at the core of Power + + + align:start position:0% +sits at the core of Power +Electronics okay and as I said we're + + align:start position:0% +Electronics okay and as I said we're + + + align:start position:0% +Electronics okay and as I said we're +going to look at all of the aspects how + + align:start position:0% +going to look at all of the aspects how + + + align:start position:0% +going to look at all of the aspects how +do you design these things how do you + + align:start position:0% +do you design these things how do you + + + align:start position:0% +do you design these things how do you +control them how do you design the + + align:start position:0% +control them how do you design the + + + align:start position:0% +control them how do you design the +components and by the time we're done + + align:start position:0% +components and by the time we're done + + + align:start position:0% +components and by the time we're done +you should be able to put it all + + align:start position:0% +you should be able to put it all + + + align:start position:0% +you should be able to put it all +together and and start designing Power + + align:start position:0% +together and and start designing Power + + + align:start position:0% +together and and start designing Power +Electronics of your own and you will for + + align:start position:0% +Electronics of your own and you will for + + + align:start position:0% +Electronics of your own and you will for +the final project + + align:start position:0% +the final project + + + align:start position:0% +the final project +okay so any final questions + + align:start position:0% + + + + align:start position:0% + +okay we'll wrap up today and I will see + + align:start position:0% +okay we'll wrap up today and I will see + + + align:start position:0% +okay we'll wrap up today and I will see +everybody on Wednesday \ No newline at end of file diff --git a/fsF79kN9G28.txt b/fsF79kN9G28.txt new file mode 100644 index 0000000000000000000000000000000000000000..0bcaea632a8325be25fea722d2334165ce30e360 --- /dev/null +++ b/fsF79kN9G28.txt @@ -0,0 +1,232 @@ +Let us discuss the performance +of a benchmark algorithm. + +The Random Forest +algorithm is known + +for its attractive property of +detecting variable interactions + +and excellent performance +as a learning algorithm. + +For the decision, we're +selecting the Random Forest + +algorithm as a +benchmark-- initially, + +we randomly partitioned +the full data + +set into two separate parts, +where the split was 50-50, + +and the partitioning was done +evenly within each cost bin. + +The first part, +the training set, + +was used to develop the method. + +The second part, +the test set, was + +used to evaluate the +model's performance. + +The table in this slide +reports the accuracy + +of the Random Forest algorithm +on each of the three buckets. + +Let us now introduce +the idea of clustering. + +Patients in each bucket may +have different characteristics. + +For this reason, we create +clusters for each cost bucket + +and make predictions for each +cluster using the Random Forest + +algorithm. + +Clustering is mostly used in +the absence of a target variable + +to search for relationships +among input variables + +or to organize data +into meaningful groups. + +In this study, although +the target variable + +is well-defined as a heart +attack or not a heart attack, + +there are many +different trajectories + +that are associated +with the target. + +There's not one set +pattern of health + +or diagnostic combination that +leads a person to heart attack. + +Instead, we'll +show that there are + +many different dynamic health +patterns and time series + +diagnostic relations +preceding a heart attack. + +The clustering +methods were used were + +spectral clustering +and k-means clustering. + +We focus, in the lecture, +on the k-means clustering. + +The broad description of +the algorithm is as follows. + +We first specify the +number of clusters k. + +Then we randomly assign each +data point to a cluster. + +We then compute the +cluster centroids. + +We re-assign each point to +the closest cluster centroid. + +We then re-compute +the cluster centroids, + +and we repeat steps 4 and 5 +until no improvement is made. + +Let us illustrate the +k-means algorithm in action. + +We specify the desired +number of clusters k. + +In this case, we use k=2. + +We then randomly assign each +data point to a cluster. + +In this case, we have +the three points in red, + +and the two points in black. + +We then compute the +cluster centroids, + +indicated by the red +x and the grey x. + +We re-assign each point to +the closest cluster centroid, + +and now you observe that +this point changes from a red + +to a grey. + +We re-compute the +cluster centroids, + +and we repeat the +previous steps, 4 and 5 + +until no improvement is made. + +We observe that, in this case, +the k-means clustering is done, + +and this is our +final clustering. + +Let us discuss some +practical considerations. + +The number of clusters +k can be selected + +from previous knowledge or +by simply experimenting. + +We can strategically select +initial partition of points + +into clusters if we have +some knowledge of the data. + +We can also run the +algorithm several times + +with different random +starting points. + +In the recitations, +we'll learn how + +to run the k-means +algorithm in R. + +So how do we +measure performance? + +After we construct the +clusters in the training set, + +we assign new observations +to clusters by proximity + +to the centroid of each cluster. + +We measure performance +by recording + +the average performance +rate in each cluster. + +Let us now discuss the +performance of the clustering + +methods. + +We perform clustering on each +bucket using k=10 clusters. + +In the table we record +the average prediction + +rate of each cost bucket. + +We observe a very +visible improvement + +when we use clustering-- from +49% to 64%, from 56% to 73%, + +from 58% to 78%. \ No newline at end of file diff --git a/fv5QB3eK7jA.txt b/fv5QB3eK7jA.txt new file mode 100644 index 0000000000000000000000000000000000000000..1b7e64ae40780e8c2f21371c9e7b7565aeac7ae7 --- /dev/null +++ b/fv5QB3eK7jA.txt @@ -0,0 +1,2635 @@ +align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +why does going to the airport seem to + + align:start position:0% +why does going to the airport seem to + + + align:start position:0% +why does going to the airport seem to +require extra time compared with coming + + align:start position:0% +require extra time compared with coming + + + align:start position:0% +require extra time compared with coming +back from the airport even if the + + align:start position:0% +back from the airport even if the + + + align:start position:0% +back from the airport even if the +traffic is the same in both directions + + align:start position:0% +traffic is the same in both directions + + + align:start position:0% +traffic is the same in both directions +the answer must somehow depend on more + + align:start position:0% +the answer must somehow depend on more + + + align:start position:0% +the answer must somehow depend on more +than just the average travel time which + + align:start position:0% +than just the average travel time which + + + align:start position:0% +than just the average travel time which +we're assuming is the same and often is + + align:start position:0% +we're assuming is the same and often is + + + align:start position:0% +we're assuming is the same and often is +in fact it often depends on the + + align:start position:0% +in fact it often depends on the + + + align:start position:0% +in fact it often depends on the +distribution of travel times probability + + align:start position:0% +distribution of travel times probability + + + align:start position:0% +distribution of travel times probability +distributions are fully described by + + align:start position:0% +distributions are fully described by + + + align:start position:0% +distributions are fully described by +listing or graphing every probability + + align:start position:0% +listing or graphing every probability + + + align:start position:0% +listing or graphing every probability +for example How likely is a journey to + + align:start position:0% +for example How likely is a journey to + + + align:start position:0% +for example How likely is a journey to +the airport to be between 10 and 20 + + align:start position:0% +the airport to be between 10 and 20 + + + align:start position:0% +the airport to be between 10 and 20 +minutes How likely is a 20 to 30-minute + + align:start position:0% +minutes How likely is a 20 to 30-minute + + + align:start position:0% +minutes How likely is a 20 to 30-minute +Journey a 30 to 40 minute journey and so + + align:start position:0% +Journey a 30 to 40 minute journey and so + + + align:start position:0% +Journey a 30 to 40 minute journey and so +on we'll answer the airport question at + + align:start position:0% +on we'll answer the airport question at + + + align:start position:0% +on we'll answer the airport question at +the end of the video this video is part + + align:start position:0% +the end of the video this video is part + + + align:start position:0% +the end of the video this video is part +of the probability and statistics video + + align:start position:0% +of the probability and statistics video + + + align:start position:0% +of the probability and statistics video +series many natural and social phenomena + + align:start position:0% +series many natural and social phenomena + + + align:start position:0% +series many natural and social phenomena +are probabilistic in nature Engineers + + align:start position:0% +are probabilistic in nature Engineers + + + align:start position:0% +are probabilistic in nature Engineers +scientists and policy makers often use + + align:start position:0% +scientists and policy makers often use + + + align:start position:0% +scientists and policy makers often use +probability to model and predict system + + align:start position:0% +probability to model and predict system + + + align:start position:0% +probability to model and predict system +Behavior hi my name is sanjoy Mahajan + + align:start position:0% +Behavior hi my name is sanjoy Mahajan + + + align:start position:0% +Behavior hi my name is sanjoy Mahajan +and I'm a professor of applied science + + align:start position:0% +and I'm a professor of applied science + + + align:start position:0% +and I'm a professor of applied science +and engineering at ol College before + + align:start position:0% +and engineering at ol College before + + + align:start position:0% +and engineering at ol College before +watching this video you should be + + align:start position:0% +watching this video you should be + + + align:start position:0% +watching this video you should be +proficient with integration and have + + align:start position:0% +proficient with integration and have + + + align:start position:0% +proficient with integration and have +some familiarity with probabilities + + align:start position:0% +some familiarity with probabilities + + + align:start position:0% +some familiarity with probabilities +after watching this video you will be + + align:start position:0% +after watching this video you will be + + + align:start position:0% +after watching this video you will be +able to explain what moments of + + align:start position:0% +able to explain what moments of + + + align:start position:0% +able to explain what moments of +distributions are and compute moments + + align:start position:0% +distributions are and compute moments + + + align:start position:0% +distributions are and compute moments +and understand what they + + align:start position:0% + + + + align:start position:0% + +mean to illustrate what a probability + + align:start position:0% +mean to illustrate what a probability + + + align:start position:0% +mean to illustrate what a probability +distribution is is let's consider + + align:start position:0% +distribution is is let's consider + + + align:start position:0% +distribution is is let's consider +rolling two Fair dice the probability + + align:start position:0% +rolling two Fair dice the probability + + + align:start position:0% +rolling two Fair dice the probability +distribution of their sum is this table + + align:start position:0% +distribution of their sum is this table + + + align:start position:0% +distribution of their sum is this table +for example the only way to get a sum of + + align:start position:0% +for example the only way to get a sum of + + + align:start position:0% +for example the only way to get a sum of +two is to roll a one on each die and + + align:start position:0% +two is to roll a one on each die and + + + align:start position:0% +two is to roll a one on each die and +there are 36 possible rolls for a pair + + align:start position:0% +there are 36 possible rolls for a pair + + + align:start position:0% +there are 36 possible rolls for a pair +of dice so getting a sum of two has a + + align:start position:0% +of dice so getting a sum of two has a + + + align:start position:0% +of dice so getting a sum of two has a +probability of 1 over + + align:start position:0% +probability of 1 over + + + align:start position:0% +probability of 1 over +36 the probability of rolling a sum of + + align:start position:0% +36 the probability of rolling a sum of + + + align:start position:0% +36 the probability of rolling a sum of +three is 2 over 36 and so on and so + + align:start position:0% +three is 2 over 36 and so on and so + + + align:start position:0% +three is 2 over 36 and so on and so +forth you can fill in a table like this + + align:start position:0% +forth you can fill in a table like this + + + align:start position:0% +forth you can fill in a table like this +your but the whole distribution even for + + align:start position:0% +your but the whole distribution even for + + + align:start position:0% +your but the whole distribution even for +something as simple as two dice is + + align:start position:0% +something as simple as two dice is + + + align:start position:0% +something as simple as two dice is +usually too much + + align:start position:0% +usually too much + + + align:start position:0% +usually too much +information we often want to + + align:start position:0% +information we often want to + + + align:start position:0% +information we often want to +characterize the shape of the + + align:start position:0% +characterize the shape of the + + + align:start position:0% +characterize the shape of the +distribution using only a few + + align:start position:0% +distribution using only a few + + + align:start position:0% +distribution using only a few +numbers of course that throws away + + align:start position:0% +numbers of course that throws away + + + align:start position:0% +numbers of course that throws away +information but throwing away + + align:start position:0% +information but throwing away + + + align:start position:0% +information but throwing away +information is the only way to fit the + + align:start position:0% +information is the only way to fit the + + + align:start position:0% +information is the only way to fit the +complexity of the world into our brains + + align:start position:0% +complexity of the world into our brains + + + align:start position:0% +complexity of the world into our brains +the art comes in keeping the most + + align:start position:0% +the art comes in keeping the most + + + align:start position:0% +the art comes in keeping the most +important + + align:start position:0% +important + + + align:start position:0% +important +information finding the moments of a + + align:start position:0% +information finding the moments of a + + + align:start position:0% +information finding the moments of a +distribution can help us reach our + + align:start position:0% +distribution can help us reach our + + + align:start position:0% +distribution can help us reach our +goal two moments that you are probably + + align:start position:0% +goal two moments that you are probably + + + align:start position:0% +goal two moments that you are probably +already familiar with are mean and + + align:start position:0% +already familiar with are mean and + + + align:start position:0% +already familiar with are mean and +variance they are the two most important + + align:start position:0% +variance they are the two most important + + + align:start position:0% +variance they are the two most important +moments of + + align:start position:0% +moments of + + + align:start position:0% +moments of +distributions let's define these moments + + align:start position:0% +distributions let's define these moments + + + align:start position:0% +distributions let's define these moments +more formally the mean is the first + + align:start position:0% +more formally the mean is the first + + + align:start position:0% +more formally the mean is the first +moment of a + + align:start position:0% +moment of a + + + align:start position:0% +moment of a +distribution it is also called the + + align:start position:0% +distribution it is also called the + + + align:start position:0% +distribution it is also called the +expected value and is computed as + + align:start position:0% +expected value and is computed as + + + align:start position:0% +expected value and is computed as +shown expected value of x that's x with + + align:start position:0% +shown expected value of x that's x with + + + align:start position:0% +shown expected value of x that's x with +angled brackets around it is equal to + + align:start position:0% +angled brackets around it is equal to + + + align:start position:0% +angled brackets around it is equal to +this sum it's the weighted sum of all + + align:start position:0% +this sum it's the weighted sum of all + + + align:start position:0% +this sum it's the weighted sum of all +the X's weighted by their + + align:start position:0% +the X's weighted by their + + + align:start position:0% +the X's weighted by their +probabilities let the x of I be the + + align:start position:0% +probabilities let the x of I be the + + + align:start position:0% +probabilities let the x of I be the +possible values of X for example for the + + align:start position:0% +possible values of X for example for the + + + align:start position:0% +possible values of X for example for the +rolling of two dice the possible values + + align:start position:0% +rolling of two dice the possible values + + + align:start position:0% +rolling of two dice the possible values +for X of I would be 2 3 4 all the way up + + align:start position:0% +for X of I would be 2 3 4 all the way up + + + align:start position:0% +for X of I would be 2 3 4 all the way up +through 12 and P ofi would be the + + align:start position:0% +through 12 and P ofi would be the + + + align:start position:0% +through 12 and P ofi would be the +corresponding probabilities of rolling + + align:start position:0% +corresponding probabilities of rolling + + + align:start position:0% +corresponding probabilities of rolling +those sums so that was 1 over 36 2 over + + align:start position:0% +those sums so that was 1 over 36 2 over + + + align:start position:0% +those sums so that was 1 over 36 2 over +36 and so on so the first moment gives + + align:start position:0% +36 and so on so the first moment gives + + + align:start position:0% +36 and so on so the first moment gives +us some idea of what our distribution + + align:start position:0% +us some idea of what our distribution + + + align:start position:0% +us some idea of what our distribution +might look like but not much + + align:start position:0% +might look like but not much + + + align:start position:0% +might look like but not much +think about it like this the center of + + align:start position:0% +think about it like this the center of + + + align:start position:0% +think about it like this the center of +mass in these two images is in the same + + align:start position:0% +mass in these two images is in the same + + + align:start position:0% +mass in these two images is in the same +place but the mass is actually + + align:start position:0% +place but the mass is actually + + + align:start position:0% +place but the mass is actually +distributed very differently in the two + + align:start position:0% +distributed very differently in the two + + + align:start position:0% +distributed very differently in the two +cases we need more information the + + align:start position:0% +cases we need more information the + + + align:start position:0% +cases we need more information the +second moment can help us the second + + align:start position:0% +second moment can help us the second + + + align:start position:0% +second moment can help us the second +moment is very similar in structure to + + align:start position:0% +moment is very similar in structure to + + + align:start position:0% +moment is very similar in structure to +the first moment we write it the same + + align:start position:0% +the first moment we write it the same + + + align:start position:0% +the first moment we write it the same +way with angled brackets but now we're + + align:start position:0% +way with angled brackets but now we're + + + align:start position:0% +way with angled brackets but now we're +talking about the expected value of x + + align:start position:0% +talking about the expected value of x + + + align:start position:0% +talking about the expected value of x +squared so it's still a sum and it's + + align:start position:0% +squared so it's still a sum and it's + + + align:start position:0% +squared so it's still a sum and it's +still weighted by the probabilities pie + + align:start position:0% +still weighted by the probabilities pie + + + align:start position:0% +still weighted by the probabilities pie +of I but now we Square each possible x + + align:start position:0% +of I but now we Square each possible x + + + align:start position:0% +of I but now we Square each possible x +value for the dice example that was the + + align:start position:0% +value for the dice example that was the + + + align:start position:0% +value for the dice example that was the +values from 2 through 12 this is also + + align:start position:0% +values from 2 through 12 this is also + + + align:start position:0% +values from 2 through 12 this is also +called the mean + + align:start position:0% +called the mean + + + align:start position:0% +called the mean +Square first you square the X values + + align:start position:0% +Square first you square the X values + + + align:start position:0% +Square first you square the X values +then you take the mean waiting each xabi + + align:start position:0% +then you take the mean waiting each xabi + + + align:start position:0% +then you take the mean waiting each xabi +by its probability pie of by in general + + align:start position:0% +by its probability pie of by in general + + + align:start position:0% +by its probability pie of by in general +the nth moment is defined as + + align:start position:0% + + + + align:start position:0% + +follows so how does the second moment + + align:start position:0% +follows so how does the second moment + + + align:start position:0% +follows so how does the second moment +help us get a better picture of our + + align:start position:0% +help us get a better picture of our + + + align:start position:0% +help us get a better picture of our +distribution because it can help us + + align:start position:0% +distribution because it can help us + + + align:start position:0% +distribution because it can help us +calculate something called the + + align:start position:0% +calculate something called the + + + align:start position:0% +calculate something called the +variance the variance measures how + + align:start position:0% +variance the variance measures how + + + align:start position:0% +variance the variance measures how +spread out the distribution is around + + align:start position:0% +spread out the distribution is around + + + align:start position:0% +spread out the distribution is around +the + + align:start position:0% +the + + + align:start position:0% +the +mean to calculate the variance you first + + align:start position:0% +mean to calculate the variance you first + + + align:start position:0% +mean to calculate the variance you first +subtract the mean from each X + + align:start position:0% +subtract the mean from each X + + + align:start position:0% +subtract the mean from each X +ofi this is like finding the distance of + + align:start position:0% +ofi this is like finding the distance of + + + align:start position:0% +ofi this is like finding the distance of +each x sub I from the mean and then you + + align:start position:0% +each x sub I from the mean and then you + + + align:start position:0% +each x sub I from the mean and then you +square the result and multiply by P sub + + align:start position:0% + + + + align:start position:0% + +I what is the dimensions of the variance + + align:start position:0% +I what is the dimensions of the variance + + + align:start position:0% +I what is the dimensions of the variance +the square of the dimensions of X for + + align:start position:0% +the square of the dimensions of X for + + + align:start position:0% +the square of the dimensions of X for +example if the dimension is a length + + align:start position:0% +example if the dimension is a length + + + align:start position:0% +example if the dimension is a length +then the variance is a length + + align:start position:0% +then the variance is a length + + + align:start position:0% +then the variance is a length +squared but we often want to measure of + + align:start position:0% +squared but we often want to measure of + + + align:start position:0% +squared but we often want to measure of +dispersion like the variance but one + + align:start position:0% +dispersion like the variance but one + + + align:start position:0% +dispersion like the variance but one +that has the same dimensions as X + + align:start position:0% +that has the same dimensions as X + + + align:start position:0% +that has the same dimensions as X +itself that measure is the standard + + align:start position:0% +itself that measure is the standard + + + align:start position:0% +itself that measure is the standard +deviation + + align:start position:0% +deviation + + + align:start position:0% +deviation +Sigma Sigma is defined as the square + + align:start position:0% +Sigma Sigma is defined as the square + + + align:start position:0% +Sigma Sigma is defined as the square +root of the variance so if the variable + + align:start position:0% +root of the variance so if the variable + + + align:start position:0% +root of the variance so if the variable +X has dimensions of length then the + + align:start position:0% +X has dimensions of length then the + + + align:start position:0% +X has dimensions of length then the +variance will have dimensions of length + + align:start position:0% +variance will have dimensions of length + + + align:start position:0% +variance will have dimensions of length +squared but the standard deviation Sigma + + align:start position:0% +squared but the standard deviation Sigma + + + align:start position:0% +squared but the standard deviation Sigma +will have dimensions of length so it's + + align:start position:0% +will have dimensions of length so it's + + + align:start position:0% +will have dimensions of length so it's +comparable to X directly this expression + + align:start position:0% +comparable to X directly this expression + + + align:start position:0% +comparable to X directly this expression +for the variance looks like a pain to + + align:start position:0% +for the variance looks like a pain to + + + align:start position:0% +for the variance looks like a pain to +compute but it has an alternative + + align:start position:0% +compute but it has an alternative + + + align:start position:0% +compute but it has an alternative +expression that is much simpler and you + + align:start position:0% +expression that is much simpler and you + + + align:start position:0% +expression that is much simpler and you +get to show that as one of the exercises + + align:start position:0% +get to show that as one of the exercises + + + align:start position:0% +get to show that as one of the exercises +after the + + align:start position:0% +after the + + + align:start position:0% +after the +video the alternative expression the + + align:start position:0% +video the alternative expression the + + + align:start position:0% +video the alternative expression the +much simpler one is that the variance is + + align:start position:0% +much simpler one is that the variance is + + + align:start position:0% +much simpler one is that the variance is +equal to the second moment our old + + align:start position:0% +equal to the second moment our old + + + align:start position:0% +equal to the second moment our old +friend minus the square of the first + + align:start position:0% +friend minus the square of the first + + + align:start position:0% +friend minus the square of the first +moment or the mean pause the video here + + align:start position:0% +moment or the mean pause the video here + + + align:start position:0% +moment or the mean pause the video here +to convince Vince yourself that this + + align:start position:0% +to convince Vince yourself that this + + + align:start position:0% +to convince Vince yourself that this +difference is always non- + + align:start position:0% + + + + align:start position:0% + +negative this alternative expression for + + align:start position:0% +negative this alternative expression for + + + align:start position:0% +negative this alternative expression for +the variance this much more useful one + + align:start position:0% +the variance this much more useful one + + + align:start position:0% +the variance this much more useful one +is also the parallel axis theorem in + + align:start position:0% +is also the parallel axis theorem in + + + align:start position:0% +is also the parallel axis theorem in +mechanics which says that the moment of + + align:start position:0% +mechanics which says that the moment of + + + align:start position:0% +mechanics which says that the moment of +inertia of an object about the center of + + align:start position:0% +inertia of an object about the center of + + + align:start position:0% +inertia of an object about the center of +mass is equal to the moment of inertia + + align:start position:0% +mass is equal to the moment of inertia + + + align:start position:0% +mass is equal to the moment of inertia +about an axis shifted by H from the + + align:start position:0% +about an axis shifted by H from the + + + align:start position:0% +about an axis shifted by H from the +center of mass a parallel shift minus + + align:start position:0% +center of mass a parallel shift minus + + + align:start position:0% +center of mass a parallel shift minus +mh^ 2 so how does this analogy + + align:start position:0% +mh^ 2 so how does this analogy + + + align:start position:0% +mh^ 2 so how does this analogy +work this the dispersion around the mean + + align:start position:0% +work this the dispersion around the mean + + + align:start position:0% +work this the dispersion around the mean +which is here at the center of Mass is + + align:start position:0% +which is here at the center of Mass is + + + align:start position:0% +which is here at the center of Mass is +like the variance this is like the + + align:start position:0% +like the variance this is like the + + + align:start position:0% +like the variance this is like the +second moment if we make H equal to the + + align:start position:0% +second moment if we make H equal to the + + + align:start position:0% +second moment if we make H equal to the +mean so this is the dispersion around + + align:start position:0% +mean so this is the dispersion around + + + align:start position:0% +mean so this is the dispersion around +zero or at second moment so this is like + + align:start position:0% +zero or at second moment so this is like + + + align:start position:0% +zero or at second moment so this is like +x^2 the expected value the mass is the + + align:start position:0% +x^2 the expected value the mass is the + + + align:start position:0% +x^2 the expected value the mass is the +sum total of all the weights here for + + align:start position:0% +sum total of all the weights here for + + + align:start position:0% +sum total of all the weights here for +each of the XI which all add up to one + + align:start position:0% +each of the XI which all add up to one + + + align:start position:0% +each of the XI which all add up to one +so this is just like one in this problem + + align:start position:0% +so this is just like one in this problem + + + align:start position:0% +so this is just like one in this problem +and then the h s well H is the mean so + + align:start position:0% +and then the h s well H is the mean so + + + align:start position:0% +and then the h s well H is the mean so +this is + + align:start position:0% +this is + + + align:start position:0% +this is +x^2 so you can see the exact same + + align:start position:0% +x^2 so you can see the exact same + + + align:start position:0% +x^2 so you can see the exact same +structure repeated with h the shift of + + align:start position:0% +structure repeated with h the shift of + + + align:start position:0% +structure repeated with h the shift of +axis as the mean and M the mass as the + + align:start position:0% +axis as the mean and M the mass as the + + + align:start position:0% +axis as the mean and M the mass as the +sum of all probabilities which is one so + + align:start position:0% +sum of all probabilities which is one so + + + align:start position:0% +sum of all probabilities which is one so +this formula for the variance is also + + align:start position:0% +this formula for the variance is also + + + align:start position:0% +this formula for the variance is also +the parallel axis + + align:start position:0% + + + + align:start position:0% + +theorem let's use the definitions of the + + align:start position:0% +theorem let's use the definitions of the + + + align:start position:0% +theorem let's use the definitions of the +moments and also of the related quantity + + align:start position:0% +moments and also of the related quantity + + + align:start position:0% +moments and also of the related quantity +the variance and practice on a few + + align:start position:0% +the variance and practice on a few + + + align:start position:0% +the variance and practice on a few +distributions a simple discrete + + align:start position:0% +distributions a simple discrete + + + align:start position:0% +distributions a simple discrete +distribution is a single coin flip + + align:start position:0% +distribution is a single coin flip + + + align:start position:0% +distribution is a single coin flip +instead of thinking of the coin flip as + + align:start position:0% +instead of thinking of the coin flip as + + + align:start position:0% +instead of thinking of the coin flip as +resulting in heads or tails let's think + + align:start position:0% +resulting in heads or tails let's think + + + align:start position:0% +resulting in heads or tails let's think +about the coin as turning up a zero or + + align:start position:0% +about the coin as turning up a zero or + + + align:start position:0% +about the coin as turning up a zero or +one let P be the probability of a one so + + align:start position:0% +one let P be the probability of a one so + + + align:start position:0% +one let P be the probability of a one so +the mean is the weighted sum of the X + + align:start position:0% +the mean is the weighted sum of the X + + + align:start position:0% +the mean is the weighted sum of the X +ofis weighted by the + + align:start position:0% +ofis weighted by the + + + align:start position:0% +ofis weighted by the +probabilities so the mean X is the sum p + + align:start position:0% +probabilities so the mean X is the sum p + + + align:start position:0% +probabilities so the mean X is the sum p +subi x subi which is equal to 1 - P * 0 + + align:start position:0% +subi x subi which is equal to 1 - P * 0 + + + align:start position:0% +subi x subi which is equal to 1 - P * 0 ++ P * 1 which is equal to P what about + + align:start position:0% ++ P * 1 which is equal to P what about + + + align:start position:0% ++ P * 1 which is equal to P what about +the second moment the expected value of + + align:start position:0% +the second moment the expected value of + + + align:start position:0% +the second moment the expected value of +x^2 it's equal to the weighted sum of + + align:start position:0% +x^2 it's equal to the weighted sum of + + + align:start position:0% +x^2 it's equal to the weighted sum of +the xub by^ squ so the weights are the + + align:start position:0% +the xub by^ squ so the weights are the + + + align:start position:0% +the xub by^ squ so the weights are the +same as + + align:start position:0% +same as + + + align:start position:0% +same as +before we then Square each value here + + align:start position:0% +before we then Square each value here + + + align:start position:0% +before we then Square each value here +each X of I but since they're all zero + + align:start position:0% +each X of I but since they're all zero + + + align:start position:0% +each X of I but since they're all zero +or one squaring doesn't change them so + + align:start position:0% +or one squaring doesn't change them so + + + align:start position:0% +or one squaring doesn't change them so +the second moment and the third moment + + align:start position:0% +the second moment and the third moment + + + align:start position:0% +the second moment and the third moment +and every higher moment are all also + + align:start position:0% +and every higher moment are all also + + + align:start position:0% +and every higher moment are all also +P pause the video here and compute the + + align:start position:0% +P pause the video here and compute the + + + align:start position:0% +P pause the video here and compute the +variance and sketch it as a function of + + align:start position:0% + + + + align:start position:0% + +P the variance from our old convenient + + align:start position:0% +P the variance from our old convenient + + + align:start position:0% +P the variance from our old convenient +form of the formula is the mean squar + + align:start position:0% +form of the formula is the mean squar + + + align:start position:0% +form of the formula is the mean squar +minus the squ mean and all the moments + + align:start position:0% +minus the squ mean and all the moments + + + align:start position:0% +minus the squ mean and all the moments +themselves were just P so that's P minus + + align:start position:0% +themselves were just P so that's P minus + + + align:start position:0% +themselves were just P so that's P minus +p^ 2 which is equal to P * 1us P what + + align:start position:0% +p^ 2 which is equal to P * 1us P what + + + align:start position:0% +p^ 2 which is equal to P * 1us P what +does that look like we'll sketch it p on + + align:start position:0% +does that look like we'll sketch it p on + + + align:start position:0% +does that look like we'll sketch it p on +this axis variance on that axis the + + align:start position:0% +this axis variance on that axis the + + + align:start position:0% +this axis variance on that axis the +curve starts at zero Rises to a peak in + + align:start position:0% +curve starts at zero Rises to a peak in + + + align:start position:0% +curve starts at zero Rises to a peak in +the middle and then goes back to zero + + align:start position:0% +the middle and then goes back to zero + + + align:start position:0% +the middle and then goes back to zero +this is a p equal 1 and that's P equal + + align:start position:0% +this is a p equal 1 and that's P equal + + + align:start position:0% +this is a p equal 1 and that's P equal +0 does that make + + align:start position:0% +0 does that make + + + align:start position:0% +0 does that make +sense yeah it does from the meaning of + + align:start position:0% +sense yeah it does from the meaning of + + + align:start position:0% +sense yeah it does from the meaning of +variance as dispersion around the + + align:start position:0% +variance as dispersion around the + + + align:start position:0% +variance as dispersion around the +mean so take the first extreme case of P + + align:start position:0% +mean so take the first extreme case of P + + + align:start position:0% +mean so take the first extreme case of P +equals 0 in other words the coin has no + + align:start position:0% +equals 0 in other words the coin has no + + + align:start position:0% +equals 0 in other words the coin has no +chance of producing a one always + + align:start position:0% +chance of producing a one always + + + align:start position:0% +chance of producing a one always +produces a zero every time there the + + align:start position:0% +produces a zero every time there the + + + align:start position:0% +produces a zero every time there the +mean is zero and there's no dispersion + + align:start position:0% +mean is zero and there's no dispersion + + + align:start position:0% +mean is zero and there's no dispersion +because it always produces zero the same + + align:start position:0% +because it always produces zero the same + + + align:start position:0% +because it always produces zero the same +applies when P equals one here at this + + align:start position:0% +applies when P equals one here at this + + + align:start position:0% +applies when P equals one here at this +extreme the coin always produces a one + + align:start position:0% +extreme the coin always produces a one + + + align:start position:0% +extreme the coin always produces a one +with no dispersion there is no variation + + align:start position:0% +with no dispersion there is no variation + + + align:start position:0% +with no dispersion there is no variation +there is no + + align:start position:0% +there is no + + + align:start position:0% +there is no +variance it's also plausible that the + + align:start position:0% +variance it's also plausible that the + + + align:start position:0% +variance it's also plausible that the +variance should be a maximum right in + + align:start position:0% +variance should be a maximum right in + + + align:start position:0% +variance should be a maximum right in +between here at P equal 12 which it is + + align:start position:0% +between here at P equal 12 which it is + + + align:start position:0% +between here at P equal 12 which it is +on this + + align:start position:0% +on this + + + align:start position:0% +on this +curve so everything looks good our + + align:start position:0% +curve so everything looks good our + + + align:start position:0% +curve so everything looks good our +calculation seems reasonable and checks + + align:start position:0% +calculation seems reasonable and checks + + + align:start position:0% +calculation seems reasonable and checks +out in the extreme + + align:start position:0% +out in the extreme + + + align:start position:0% +out in the extreme +cases before we go back to the airport + + align:start position:0% +cases before we go back to the airport + + + align:start position:0% +cases before we go back to the airport +problem let's extend the idea of moments + + align:start position:0% +problem let's extend the idea of moments + + + align:start position:0% +problem let's extend the idea of moments +to continuous + + align:start position:0% +to continuous + + + align:start position:0% +to continuous +distributions here instead of a list of + + align:start position:0% +distributions here instead of a list of + + + align:start position:0% +distributions here instead of a list of +probabilities for each possible X we + + align:start position:0% +probabilities for each possible X we + + + align:start position:0% +probabilities for each possible X we +have a probability density p as a + + align:start position:0% +have a probability density p as a + + + align:start position:0% +have a probability density p as a +function of X or X is now a continuous + + align:start position:0% +function of X or X is now a continuous + + + align:start position:0% +function of X or X is now a continuous +variable that's the continuous version + + align:start position:0% +variable that's the continuous version + + + align:start position:0% +variable that's the continuous version +of the nth moment as a sum of x ofi to + + align:start position:0% +of the nth moment as a sum of x ofi to + + + align:start position:0% +of the nth moment as a sum of x ofi to +the nth weighted by the + + align:start position:0% +the nth weighted by the + + + align:start position:0% +the nth weighted by the +probabilities here the nth moment is + + align:start position:0% +probabilities here the nth moment is + + + align:start position:0% +probabilities here the nth moment is +equal to instead of a sum an + + align:start position:0% +equal to instead of a sum an + + + align:start position:0% +equal to instead of a sum an +integral weighted again as always by the + + align:start position:0% +integral weighted again as always by the + + + align:start position:0% +integral weighted again as always by the +probability times x to the n as before + + align:start position:0% +probability times x to the n as before + + + align:start position:0% +probability times x to the n as before +and with a DX because P ofx * DX is the + + align:start position:0% +and with a DX because P ofx * DX is the + + + align:start position:0% +and with a DX because P ofx * DX is the +probability and you add them up over all + + align:start position:0% +probability and you add them up over all + + + align:start position:0% +probability and you add them up over all +possible values of + + align:start position:0% +possible values of + + + align:start position:0% +possible values of +X that's the formula for the moments of + + align:start position:0% +X that's the formula for the moments of + + + align:start position:0% +X that's the formula for the moments of +a continuous + + align:start position:0% +a continuous + + + align:start position:0% +a continuous +distribution let's practice on the + + align:start position:0% +distribution let's practice on the + + + align:start position:0% +distribution let's practice on the +simplest continuous distribution the + + align:start position:0% +simplest continuous distribution the + + + align:start position:0% +simplest continuous distribution the +uniform distribution X is equally likely + + align:start position:0% +uniform distribution X is equally likely + + + align:start position:0% +uniform distribution X is equally likely +to be any real number between 0 and 1 + + align:start position:0% +to be any real number between 0 and 1 + + + align:start position:0% +to be any real number between 0 and 1 +that's the distribution and we can + + align:start position:0% +that's the distribution and we can + + + align:start position:0% +that's the distribution and we can +compute the first and second moments and + + align:start position:0% +compute the first and second moments and + + + align:start position:0% +compute the first and second moments and +the + + align:start position:0% +the + + + align:start position:0% +the +variance pause the video here use the + + align:start position:0% +variance pause the video here use the + + + align:start position:0% +variance pause the video here use the +definition of moments for a continuous + + align:start position:0% +definition of moments for a continuous + + + align:start position:0% +definition of moments for a continuous +distribution and compute the mean the + + align:start position:0% +distribution and compute the mean the + + + align:start position:0% +distribution and compute the mean the +first moment the second moment and from + + align:start position:0% +first moment the second moment and from + + + align:start position:0% +first moment the second moment and from +those two the + + align:start position:0% + + + + align:start position:0% + +variance what you should have found is + + align:start position:0% +variance what you should have found is + + + align:start position:0% +variance what you should have found is +for the mean it's the integral of 1 + + align:start position:0% +for the mean it's the integral of 1 + + + align:start position:0% +for the mean it's the integral of 1 +because P of X is 1 * X between 0 and 1 + + align:start position:0% +because P of X is 1 * X between 0 and 1 + + + align:start position:0% +because P of X is 1 * X between 0 and 1 +DX which is x^2 / 2 evaluated between 0 + + align:start position:0% +DX which is x^2 / 2 evaluated between 0 + + + align:start position:0% +DX which is x^2 / 2 evaluated between 0 +and 1 which equals 12 which makes sense + + align:start position:0% +and 1 which equals 12 which makes sense + + + align:start position:0% +and 1 which equals 12 which makes sense +the mean here the average value is just + + align:start position:0% +the mean here the average value is just + + + align:start position:0% +the mean here the average value is just +1/2 right in the middle of the + + align:start position:0% +1/2 right in the middle of the + + + align:start position:0% +1/2 right in the middle of the +distribution of the possible values of X + + align:start position:0% +distribution of the possible values of X + + + align:start position:0% +distribution of the possible values of X +what about the mean + + align:start position:0% +what about the mean + + + align:start position:0% +what about the mean +Square for that you should have found + + align:start position:0% +Square for that you should have found + + + align:start position:0% +Square for that you should have found +almost the same calculation 1 * x^2 DX + + align:start position:0% +almost the same calculation 1 * x^2 DX + + + align:start position:0% +almost the same calculation 1 * x^2 DX +which = X Cub over 3 between 0 and 1 + + align:start position:0% +which = X Cub over 3 between 0 and 1 + + + align:start position:0% +which = X Cub over 3 between 0 and 1 +which equals 1/3 and thus the variance + + align:start position:0% +which equals 1/3 and thus the variance + + + align:start position:0% +which equals 1/3 and thus the variance +is equal to 1/3 that's the mean Square + + align:start position:0% +is equal to 1/3 that's the mean Square + + + align:start position:0% +is equal to 1/3 that's the mean Square +minus the squared mean which is + + align:start position:0% +minus the squared mean which is + + + align:start position:0% +minus the squared mean which is +112th and that number is familiar that's + + align:start position:0% +112th and that number is familiar that's + + + align:start position:0% +112th and that number is familiar that's +the same 112th that shows up in the + + align:start position:0% +the same 112th that shows up in the + + + align:start position:0% +the same 112th that shows up in the +moment of inertia of a ruler of length L + + align:start position:0% +moment of inertia of a ruler of length L + + + align:start position:0% +moment of inertia of a ruler of length L +and mass m its moment of inertia is 112 + + align:start position:0% +and mass m its moment of inertia is 112 + + + align:start position:0% +and mass m its moment of inertia is 112 +ml squ which illustrates again the + + align:start position:0% +ml squ which illustrates again the + + + align:start position:0% +ml squ which illustrates again the +connection between moments of inertia + + align:start position:0% +connection between moments of inertia + + + align:start position:0% +connection between moments of inertia +and moments of + + align:start position:0% +and moments of + + + align:start position:0% +and moments of +distributions let's apply our knowledge + + align:start position:0% +distributions let's apply our knowledge + + + align:start position:0% +distributions let's apply our knowledge +to understand quantitatively or in a + + align:start position:0% +to understand quantitatively or in a + + + align:start position:0% +to understand quantitatively or in a +formal way what happens with airport + + align:start position:0% +formal way what happens with airport + + + align:start position:0% +formal way what happens with airport +travel why does it seem so much longer + + align:start position:0% +travel why does it seem so much longer + + + align:start position:0% +travel why does it seem so much longer +on the way there than on the way back + + align:start position:0% +on the way there than on the way back + + + align:start position:0% +on the way there than on the way back +here is the ideal travel experience to + + align:start position:0% +here is the ideal travel experience to + + + align:start position:0% +here is the ideal travel experience to +the airport the distribution of travel + + align:start position:0% +the airport the distribution of travel + + + align:start position:0% +the airport the distribution of travel +times T here's the probability of each + + align:start position:0% +times T here's the probability of each + + + align:start position:0% +times T here's the probability of each +particular travel time p of tea in the + + align:start position:0% +particular travel time p of tea in the + + + align:start position:0% +particular travel time p of tea in the +ideal world the travel time would be + + align:start position:0% +ideal world the travel time would be + + + align:start position:0% +ideal world the travel time would be +very + + align:start position:0% +very + + + align:start position:0% +very +predictable let's say it would be almost + + align:start position:0% +predictable let's say it would be almost + + + align:start position:0% +predictable let's say it would be almost +always 20 minutes in that case you would + + align:start position:0% +always 20 minutes in that case you would + + + align:start position:0% +always 20 minutes in that case you would +allow 20 minutes to get to the airport + + align:start position:0% +allow 20 minutes to get to the airport + + + align:start position:0% +allow 20 minutes to get to the airport +and you would allow 20 minutes on the + + align:start position:0% +and you would allow 20 minutes on the + + + align:start position:0% +and you would allow 20 minutes on the +way back going there and coming back + + align:start position:0% +way back going there and coming back + + + align:start position:0% +way back going there and coming back +would seem the same but here's what + + align:start position:0% +would seem the same but here's what + + + align:start position:0% +would seem the same but here's what +travel to the airport actually looks + + align:start position:0% +travel to the airport actually looks + + + align:start position:0% +travel to the airport actually looks +like let's say the mean is still the + + align:start position:0% +like let's say the mean is still the + + + align:start position:0% +like let's say the mean is still the +same but the reality is that there's + + align:start position:0% +same but the reality is that there's + + + align:start position:0% +same but the reality is that there's +lots of dispersion and so so the curve + + align:start position:0% +lots of dispersion and so so the curve + + + align:start position:0% +lots of dispersion and so so the curve +actually looks like that sometimes the + + align:start position:0% +actually looks like that sometimes the + + + align:start position:0% +actually looks like that sometimes the +travel time will be 30 minutes sometimes + + align:start position:0% +travel time will be 30 minutes sometimes + + + align:start position:0% +travel time will be 30 minutes sometimes +40 sometimes + + align:start position:0% +40 sometimes + + + align:start position:0% +40 sometimes +10 so now what do you have to do this is + + align:start position:0% +10 so now what do you have to do this is + + + align:start position:0% +10 so now what do you have to do this is +reality on the way home it's no problem + + align:start position:0% +reality on the way home it's no problem + + + align:start position:0% +reality on the way home it's no problem +on average you get home in 20 minutes + + align:start position:0% +on average you get home in 20 minutes + + + align:start position:0% +on average you get home in 20 minutes +you leave whenever you get out of the + + align:start position:0% +you leave whenever you get out of the + + + align:start position:0% +you leave whenever you get out of the +baggage claim and while it's true that + + align:start position:0% +baggage claim and while it's true that + + + align:start position:0% +baggage claim and while it's true that +the trip to the airport follows the same + + align:start position:0% +the trip to the airport follows the same + + + align:start position:0% +the trip to the airport follows the same +distribution the risk to you of not + + align:start position:0% +distribution the risk to you of not + + + align:start position:0% +distribution the risk to you of not +making it to the airport on time is much + + align:start position:0% +making it to the airport on time is much + + + align:start position:0% +making it to the airport on time is much +greater if if you just allow 20 minutes + + align:start position:0% +greater if if you just allow 20 minutes + + + align:start position:0% +greater if if you just allow 20 minutes +yeah sometimes you'll get lucky but + + align:start position:0% +yeah sometimes you'll get lucky but + + + align:start position:0% +yeah sometimes you'll get lucky but +every once in a while it will take you + + align:start position:0% +every once in a while it will take you + + + align:start position:0% +every once in a while it will take you +25 or 30 minutes so what you have to do + + align:start position:0% +25 or 30 minutes so what you have to do + + + align:start position:0% +25 or 30 minutes so what you have to do +is allow more time on the way there so + + align:start position:0% +is allow more time on the way there so + + + align:start position:0% +is allow more time on the way there so +that you don't miss your flight maybe 30 + + align:start position:0% +that you don't miss your flight maybe 30 + + + align:start position:0% +that you don't miss your flight maybe 30 +minutes maybe even 40 minutes it all + + align:start position:0% +minutes maybe even 40 minutes it all + + + align:start position:0% +minutes maybe even 40 minutes it all +depends on the dispersion or standard + + align:start position:0% +depends on the dispersion or standard + + + align:start position:0% +depends on the dispersion or standard +deviation of the Distribution on the way + + align:start position:0% +deviation of the Distribution on the way + + + align:start position:0% +deviation of the Distribution on the way +to the airport you are much more aware + + align:start position:0% +to the airport you are much more aware + + + align:start position:0% +to the airport you are much more aware +of the distribution if you will than you + + align:start position:0% +of the distribution if you will than you + + + align:start position:0% +of the distribution if you will than you +are on the way back + + align:start position:0% + + + + align:start position:0% + +in this video we saw how to calculate + + align:start position:0% +in this video we saw how to calculate + + + align:start position:0% +in this video we saw how to calculate +the moments of a distribution and how + + align:start position:0% +the moments of a distribution and how + + + align:start position:0% +the moments of a distribution and how +these moments can help us quickly + + align:start position:0% +these moments can help us quickly + + + align:start position:0% +these moments can help us quickly +summarize the + + align:start position:0% +summarize the + + + align:start position:0% +summarize the +distribution like life when something is + + align:start position:0% +distribution like life when something is + + + align:start position:0% +distribution like life when something is +complicated simplify it grasp it and + + align:start position:0% +complicated simplify it grasp it and + + + align:start position:0% +complicated simplify it grasp it and +understand it by appreciating its + + align:start position:0% +understand it by appreciating its + + + align:start position:0% +understand it by appreciating its +moments + + align:start position:0% + + + + align:start position:0% + +[Music] \ No newline at end of file diff --git a/gMTiAeE0NCw.txt b/gMTiAeE0NCw.txt new file mode 100644 index 0000000000000000000000000000000000000000..91fe72d53e91c496d4c764a26cad540458b39b71 --- /dev/null +++ b/gMTiAeE0NCw.txt @@ -0,0 +1,2455 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high quality educational +resources for free. + +To make a donation or view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu. + +PROFESSOR: So by now you have +seen pretty much every + +possible trick there is in +basic probability theory, + +about how to calculate +distributions, and so on. + +You have the basic tools to +do pretty much anything. + +So what's coming after this? + +Well, probability is useful for +developing the science of + +inference, and this is a subject +to which we're going + +to come back at the end +of the semester. + +Another chapter, which is what +we will be doing over the next + +few weeks, is to deal with +phenomena that evolve in time. + +So so-called random processes +or stochastic processes. + +So what is this about? + +So in the real world, you don't +just throw two random + +variables and go home. + +Rather the world goes on. + +So you generate the random +variable, then you get more + +random variables, and things +evolve in time. + +And random processes are +supposed to be models that + +capture the evolution of random +phenomena over time. + +So that's what we +will be doing. + +Now when we have evolution in +time, mathematically speaking, + +you can use discrete time +or continuous time. + +Of course, discrete +time is easier. + +And that's where we're +going to start from. + +And we're going to start from +the easiest, simplest random + +process, which is the so-called +Bernoulli process, + +which is nothing but just a +sequence of coin flips. + +You keep flipping a coin +and keep going forever. + +That's what the Bernoulli +process is. + +So in some sense it's something +that you have + +already seen. + +But we're going to introduce a +few additional ideas here that + +will be useful and relevant as +we go along and we move on to + +continuous time processes. + +So we're going to define the +Bernoulli process, talk about + +some basic properties that the +process has, and derive a few + +formulas, and exploit the +special structure that it has + +to do a few quite interesting +things. + +By the way, where does the +word Bernoulli come from? + +Well the Bernoulli's were a +family of mathematicians, + +Swiss mathematicians and +scientists around the 1700s. + +There were so many of +them that actually-- + +and some of them had the +same first name-- + +historians even have difficulty +of figuring out who + +exactly did what. + +But in any case, you can imagine +that at the dinner + +table they were probably +flipping coins and doing + +Bernoulli trials. + +So maybe that was +their pass-time. + +OK. + +So what is the Bernoulli +process? + +The Bernoulli process is nothing +but a sequence of + +independent Bernoulli +trials that you can + +think of as coin flips. + +So you can think the result +of each trial + +being heads or tails. + +It's a little more convenient +maybe to talk about successes + +and failures instead +of heads or tails. + +Or if you wish numerical values, +to use a 1 for a + +success and 0 for a failure. + +So the model is that each one +of these trials has the same + +probability of success, p. + +And the other assumption is +that these trials are + +statistically independent +of each other. + +So what could be some examples +of Bernoulli trials? + +You buy a lottery ticket every +week and you win or lose. + +Presumably, these are +independent of each other. + +And if it's the same kind of +lottery, the probability of + +winning should be the same +during every week. + +Maybe you want to model +the financial markets. + +And a crude model could be that +on any given day the Dow + +Jones is going to go up +or down with a certain + +probability. + +Well that probability must be +somewhere around 0.5, or so. + +This is a crude model of +financial markets. + +You say, probably there +is more into them. + +Life is not that simple. + +But actually it's a pretty +reasonable model. + +It takes quite a bit of work +to come up with more + +sophisticated models that can +do better predictions than + +just pure heads and tails. + +Now more interesting, perhaps +to the examples we will be + +dealing with in this class-- + +a Bernoulli process is a good +model for streams of arrivals + +of any kind to a facility. + +So it could be a bank, and +you are sitting at + +the door of the bank. + +And at every second, you check +whether a customer came in + +during that second or not. + +Or you can think about arrivals +of jobs to a server. + +Or any other kind of requests +to a service system. + +So requests, or jobs, arrive +at random times. + +You split the time +into time slots. + +And during each time slot +something comes or something + +does not come. + +And for many applications, it's +a reasonable assumption + +to make that arrivals on any +given slot are independent of + +arrivals in any other +time slot. + +So each time slot can be viewed +as a trial, where + +either something comes +or doesn't come. + +And different trials are +independent of each other. + +Now there's two assumptions +that we're making here. + +One is the independence +assumption. + +The other is that this number, +p, probability + +of success, is constant. + +Now if you think about the bank +example, if you stand + +outside the bank at 9:30 in +the morning, you'll see + +arrivals happening at +a certain rate. + +If you stand outside the bank +at 12:00 noon, probably + +arrivals are more frequent. + +Which means that the given +time slot has a higher + +probability of seeing an arrival +around noon time. + +This means that the assumption +of a constant p is probably + +not correct in that setting, +if you're talking + +about the whole day. + +So the probability of successes +or arrivals in the + +morning is going to be smaller +than what it would be at noon. + +But if you're talking about a +time period, let's say 10:00 + +to 10:15, probably all slots +have the same probability of + +seeing an arrival and it's +a good approximation. + +So we're going to stick with +the assumption that p is + +constant, doesn't change +with time. + +Now that we have our model +what do we do with it? + +Well, we start talking about +the statistical properties + +that it has. + +And here there's two slightly +different perspectives of + +thinking about what a +random process is. + +The simplest version is to think +about the random process + +as being just a sequence +of random variables. + +We know what random +variables are. + +We know what multiple random +variables are. + +So it's just an experiment that +has associated with it a + +bunch of random variables. + +So once you have random +variables, what do you do + +instinctively? + +You talk about the +distribution of + +these random variables. + +We already specified for the +Bernoulli process that each Xi + +is a Bernoulli random variable, +with probability of + +success equal to p. + +That specifies the distribution +of the random + +variable X, or Xt, for +general time t. + +Then you can calculate +expected values and + +variances, and so on. + +So the expected value is, with +probability p, you get a 1. + +And with probability +1 - p, you get a 0. + +So the expected value +is equal to p. + +And then we have seen before a +formula for the variance of + +the Bernoulli random variable, +which is p times 1-p. + +So this way we basically now +have all the statistical + +properties of the random +variable Xt, and we have those + +properties for every t. + +Is this enough of a +probabilistic description of a + +random process? + +Well, no. + +You need to know how the +different random variables + +relate to each other. + +If you're talking about a +general random process, you + +would like to know things. + +For example, the joint +distribution of X2, + +with X5, and X7. + +For example, that might be +something that you're + +interested in. + +And the way you specify it is +by giving the joint PMF of + +these random variables. + +And you have to do that for +every collection, or any + +subset, of the random +variables you + +are interested in. + +So to have a complete +description of a random + +processes, you need to specify +for me all the possible joint + +distributions. + +And once you have all the +possible joint distributions, + +then you can answer, in +principle, any questions you + +might be interested in. + +How did we get around +this issue for + +the Bernoulli process? + +I didn't give you the joint +distributions explicitly. + +But I gave them to +you implicitly. + +And this is because I told you +that the different random + +variables are independent +of each other. + +So at least for the Bernoulli +process, where we make the + +independence assumption, we know +that this is going to be + +the product of the PMFs. + +And since I have told you what +the individual PMFs are, this + +means that you automatically +know all the joint PMFs. + +And we can go to business +based on that. + +All right. + +So this is one view of what a +random process is, just a + +collection of random +variables. + +There's another view that's a +little more abstract, which is + +the following. + +The entire process is to be +thought of as one long + +experiment. + +So we go back to the +chapter one view of + +probabilistic models. + +So there must be a sample +space involved. + +What is the sample space? + +If I do my infinite, long +experiment of flipping an + +infinite number of coins, +a typical outcome of the + +experiment would be a sequence +of 0's and 1's. + +So this could be one possible +outcome of the experiment, + +just an infinite sequence +of 0's and 1's. + +My sample space is the +set of all possible + +outcomes of this kind. + +Here's another possible +outcome, and so on. + +And essentially we're dealing +with a sample space, which is + +the space of all sequences +of 0's and 1's. + +And we're making some sort of +probabilistic assumption about + +what may happen in +that experiment. + +So one particular sequence that +we may be interested in + +is the sequence of obtaining +all 1's. + +So this is the sequence that +gives you 1's forever. + +Once you take the point of view +that this is our sample + +space-- its the space of all +infinite sequences-- + +you can start asking questions +that have to do + +with infinite sequences. + +Such as the question, what's the +probability of obtaining + +the infinite sequence that +consists of all 1's? + +So what is this probability? + +Let's see how we could +calculate it. + +So the probability of obtaining +all 1's is certainly + +less than or equal to the +probability of obtaining 1's, + +just in the first 10 tosses. + +OK. + +This is asking for more things +to happen than this. + +If this event is true, then +this is also true. + +Therefore the probability of +this is smaller than the + +probability of that. + +This event is contained +in that event. + +This implies this. + +So we have this inequality. + +Now what's the probability of +obtaining 1's in 10 trials? + +This is just p to the 10th +because the trials are + +independent. + +Now of course there's no reason +why I chose 10 here. + +The same argument goes +through if I use an + +arbitrary number, k. + +And this has to be +true for all k. + +So this probability is less +than p to the k, no matter + +what k I choose. + +Therefore, this must be less +than or equal to the limit of + +this, as k goes to infinity. + +This is smaller than +that for all k's. + +Let k go to infinity, take k +arbitrarily large, this number + +is going to become arbitrarily +small. + +It goes to 0. + +And that proves that the +probability of an infinite + +sequence of 1's is equal to 0. + +So take limits of both sides. + +It's going to be less than +or equal to the limit-- + +I shouldn't take a limit here. + +The probability is less than or +equal to the limit of p to + +the k, as k goes to infinity, +which is 0. + +So this proves in a formal way +that the sequence of all 1's + +has 0 probability. + +If you have an infinite number +of coin flips, what's the + +probability that all of the coin +flips result in heads? + +The probability of this +happening is equal to zero. + +So this particular sequence +has 0 probability. + +Of course, I'm assuming here +that p is less than 1, + +strictly less than 1. + +Now the interesting thing is +that if you look at any other + +infinite sequence, and you try +to calculate the probability + +of that infinite sequence, you +would get a product of (1-p) + +times 1, 1-p times 1, 1-p, +times p times p, + +times 1-p and so on. + +You keep multiplying numbers +that are less than 1. + +Again, I'm making the +assumption that p is + +between 0 and 1. + +So 1-p is less than 1, +p is less than 1. + +You keep multiplying numbers +less than 1. + +If you multiply infinitely +many such numbers, the + +infinite product becomes 0. + +So any individual sequence in +this sample space actually has + +0 probability. + +And that is a little bit +counter-intuitive perhaps. + +But the situation is more like +the situation where we deal + +with continuous random +variables. + +So if you could draw a +continuous random variable, + +every possible outcome +has 0 probability. + +And that's fine. + +But all of the outcomes +collectively still have + +positive probability. + +So the situation here is +very much similar. + +So the space of infinite +sequences of 0's and 1's, that + +sample space is very much +like a continuous space. + +If you want to push that analogy +further, you could + +think of this as the expansion +of a real number. + +Or the representation of a +real number in binary. + +Take a real number, write it +down in binary, you are going + +to get an infinite sequence +of 0's and 1's. + +So you can think of each +possible outcome here + +essentially as a real number. + +So the experiment of doing an +infinite number of coin flips + +is sort of similar to the +experiment of picking a real + +number at random. + +When you pick real numbers at +random, any particular real + +number has 0 probability. + +So similarly here, any +particular infinite sequence + +has 0 probability. + +So if we were to push that +analogy further, there would + +be a few interesting +things we could do. + +But we will not push +it further. + +This is just to give you an +indication that things can get + +pretty subtle and interesting +once you start talking about + +random processes that involve +forever, over the infinite + +time horizon. + +So things get interesting even +in this context of the simple + +Bernoulli process. + +Just to give you a preview of +what's coming further, today + +we're going to talk just about +the Bernoulli process. + +And you should make sure before +the next lecture-- + +I guess between the exam +and the next lecture-- + +to understand everything +we do today. + +Because next time we're going +to do everything once more, + +but in continuous time. + +And in continuous time, things +become more subtle and a + +little more difficult. + +But we are going to build on +what we understand for the + +discrete time case. + +Now both the Bernoulli process +and its continuous time analog + +has a property that we call +memorylessness, whatever + +happened in the past does +not affect the future. + +Later on in this class we're +going to talk about more + +general random processes, +so-called Markov chains, in + +which there are certain +dependences across time. + +That is, what has happened in +the past will have some + +bearing on what may happen +in the future. + +So it's like having coin flips +where the outcome of the next + +coin flip has some dependence +on the previous coin flip. + +And that gives us a richer +class of models. + +And once we get there, +essentially we will have + +covered all possible models. + +So for random processes that +are practically useful and + +which you can manipulate, Markov +chains are a pretty + +general class of models. + +And almost any real world +phenomenon that evolves in + +time can be approximately +modeled using Markov chains. + +So even though this is a first +class in probability, we will + +get pretty far in +that direction. + +All right. + +So now let's start doing a few +calculations and answer some + +questions about the +Bernoulli process. + +So again, the best way to think +in terms of models that + +correspond to the Bernoulli +process is in terms of + +arrivals of jobs +to a facility. + +And there's two types of +questions that you can ask. + +In a given amount of time, +how many jobs arrived? + +Or conversely, for a given +number of jobs, how much time + +did it take for them +to arrive? + +So we're going to deal with +these two questions, starting + +with the first. + +For a given amount of time-- + +that is, for a given number +of time periods-- + +how many arrivals have we had? + +How many of those Xi's +happen to be 1's? + +We fix the number +of time slots-- + +let's say n time slots-- + +and you measure the number +of successes. + +Well this is a very familiar +random variable. + +The number of successes in n +independent coin flips-- + +or in n independent trials-- + +is a binomial random variable. + +So we know its distribution is +given by the binomial PMF, and + +it's just this, for k going +from 0 up to n. + +And we know everything by now +about this random variable. + +We know its expected +value is n times p. + +And we know the variance, which +is n times p, times 1-p. + +So there's nothing new here. + +That's the easy part. + +So now let's look at the +opposite kind of question. + +Instead of fixing the time and +asking how many arrivals, now + +let us fix the number of +arrivals and ask how much time + +did it take. + +And let's start with the time +until the first arrival. + +So the process starts. + +We got our slots. + +And we see, perhaps, a sequence +of 0's and then at + +some point we get a 1. + +The number of trials it took +until we get a 1, we're going + +to call it T1. + +And it's the time of +the first arrival. + +OK. + +What is the probability +distribution of T1? + +What kind of random +variable is it? + +We've gone through +this before. + +The event that the first arrival +happens at time little + +t is the event that the first +t-1 trials were failures, and + +the trial number t happens +to be a success. + +So for the first success to +happen at time slot number 5, + +it means that the first 4 slots +had failures and the 5th + +slot had a success. + +So the probability of this +happening is the probability + +of having failures in the first +t -1 trials, and having + +a success at trial number 1. + +And this is the formula for +t equal 1,2, and so on. + +So we know what this +distribution is. + +It's the so-called geometric +distribution. + +Let me jump this through +this for a minute. + +In the past, we did calculate +the expected value of the + +geometric distribution, +and it's 1/p. + +Which means that if p is small, +you expect to take a + +long time until the +first success. + +And then there's a formula also +for the variance of T1, + +which we never formally derived +in class, but it was + +in your textbook and it just +happens to be this. + +All right. + +So nothing new until +this point. + +Now, let's talk about +this property, the + +memorylessness property. + +We kind of touched on this +property when we discussed-- + +when we did the derivation +in class of the + +expected value of T1. + +Now what is the memoryless +property? + +It's essentially a consequence +of independence. + +If I tell you the results of my +coin flips up to a certain + +time, this, because of +independence, doesn't give you + +any information about the coin +flips after that time. + +So knowing that we had lots of +0's here does not change what + +I believe about the future coin +flips, because the future + +coin flips are going to be just +independent coin flips + +with a given probability, +p, for obtaining tails. + +So this is a statement that I +made about a specific time. + +That is, you do coin flips +until 12 o'clock. + +And then at 12 o'clock, +you start watching. + +No matter what happens before 12 +o'clock, after 12:00, what + +you're going to see is just +a sequence of independent + +Bernoulli trials with the +same probability, p. + +Whatever happened in the +past is irrelevant. + +Now instead of talking about +the fixed time at which you + +start watching, let's think +about a situation where your + +sister sits in the next room, +flips the coins until she + +observes the first success, +and then calls you inside. + +And you start watching +after this time. + +What are you're going to see? + +Well, you're going to see a coin +flip with probability p + +of success. + +You're going to see another +trial that has probability p + +as a success, and these are all +independent of each other. + +So what you're going to see +starting at that time is going + +to be just a sequence of +independent Bernoulli trials, + +as if the process was starting +at this time. + +How long it took for the first +success to occur doesn't have + +any bearing on what is going +to happen afterwards. + +What happens afterwards +is still a sequence of + +independent coin flips. + +And this story is actually +even more general. + +So your sister watches the coin +flips and at some point + +tells you, oh, something +really interesting is + +happening here. + +I got this string of a +hundred 1's in a row. + +Come and watch. + +Now when you go in there and +you start watching, do you + +expect to see something +unusual? + +There were unusual things +that happened before + +you were called in. + +Does this means that you're +going to see unusual things + +afterwards? + +No. + +Afterwards, what you're going +to see is, again, just a + +sequence of independent +coin flips. + +The fact that some strange +things happened before doesn't + +have any bearing as to what is +going to happen in the future. + +So if the roulettes in the +casino are properly made, the + +fact that there were 3 reds in +a row doesn't affect the odds + +of whether in the next +roll it's going to + +be a red or a black. + +So whatever happens in +the past-- no matter + +how unusual it is-- + +at the time when you're called +in, what's going to happen in + +the future is going to be just +independent Bernoulli trials, + +with the same probability, p. + +The only case where this story +changes is if your sister has + +a little bit of foresight. + +So your sister can look ahead +into the future and knows that + +the next 10 coin flips will be +heads, and calls you before + +those 10 flips will happen. + +If she calls you in, then what +are you going to see? + +You're not going to see +independent Bernoulli trials, + +since she has psychic powers +and she knows that the next + +ones would be 1's. + +She called you in and you will +see a sequence of 1's. + +So it's no more independent +Bernoulli trials. + +So what's the subtle +difference here? + +The future is independent from +the past, provided that the + +time that you are called and +asked to start watching is + +determined by someone who +doesn't have any foresight, + +who cannot see the future. + +If you are called in, just on +the basis of what has happened + +so far, then you don't have any + +information about the future. + +And one special case is +the picture here. + +You have your coin flips. + +Once you see a one that happens, +once you see a + +success, you are called in. + +You are called in on the basis +of what happened in the past, + +but without any foresight. + +OK. + +And this subtle distinction is +what's going to make our next + +example interesting +and subtle. + +So here's the question. + +You buy a lottery ticket every +day, so we have a Bernoulli + +process that's running +in time. + +And you're interested in the +length of the first string of + +losing days. + +What does that mean? + +So suppose that a typical +sequence of events + +could be this one. + +So what are we discussing +here? + +We're looking at the first +string of losing days, where + +losing days means 0's. + +So the string of losing days +is this string here. + +Let's call the length of that +string, L. We're interested in + +the random variable, which is +the length of this interval. + +What kind of random +variable is it? + +OK. + +Here's one possible way you +might think about the problem. + +OK. + +Starting from this time, and +looking until this time here, + +what are we looking at? + +We're looking at the time, +starting from here, until the + +first success. + +So the past doesn't matter. + +Starting from here we +have coin flips + +until the first success. + +The time until the +first success + +in a Bernoulli process-- + +we just discussed that it's a +geometric random variable. + +So your first conjecture would +be that this random variable + +here, which is 1 longer than the +one we are interested in, + +that perhaps is a geometric +random variable. + +And if this were so, then you +could say that the random + +variable, L, is a geometric, +minus 1. + +Can that be the correct +answer? + +A geometric random variable, +what values does it take? + +It takes values 1, +2, 3, and so on. + +1 minus a geometric would +take values from 0, + +1, 2, and so on. + +Can the random variable +L be 0? + +No. + +The random variable L +is the length of a + +string of losing days. + +So the shortest that L could +be, would be just 1. + +If you get just one losing day +and then you start winning, L + +would be equal to 1. + +So L cannot be 0 by definition, +which means that L + ++ 1 cannot be 1, +by definition. + +But if L +1 were geometric, +it could be equal to 1. + +Therefore this random +variable, L + ++ 1, is not a geometric. + +OK. + +Why is it not geometric? + +I started watching +at this time. + +From this time until the first +success, that should be a + +geometric random variable. + +Where's the catch? + +If I'm asked to start watching +at this time, it's because my + +sister knows that the next +one was a failure. + +This is the time where the +string of failures starts. + +In order to know that they +should start watching here, + +it's the same as if +I'm told that the + +next one is a failure. + +So to be asked to start watching +at this time requires + +that someone looked +in the future. + +And in that case, it's no longer +true that these will be + +independent Bernoulli trials. + +In fact, they're not. + +If you start watching here, +you're certain that the next + +one is a failure. + +The next one is not an +independent Bernoulli trial. + +That's why the argument that +would claim that this L + 1 is + +geometric would be incorrect. + +So if this is not the correct +answer, which + +is the correct answer? + +The correct answer +goes as follows. + +Your sister is watching. + +Your sister sees the first +failure, and then tells you, + +OK, the failures-- + +or losing days-- + +have started. + +Come in and watch. + +So you start to watching +at this time. + +And you start watching until +the first success comes. + +This will be a geometric +random variable. + +So from here to here, this +will be geometric. + +So things happen. + +You are asked to +start watching. + +After you start watching, the +future is just a sequence of + +independent Bernoulli trials. + +And the time until the first +failure occurs, this is going + +to be a geometric random +variable with parameter p. + +And then you notice that the +interval of interest is + +exactly the same as the length +of this interval. + +This starts one time step +later, and ends + +one time step later. + +So conclusion is that L is +actually geometric, with + +parameter p. + +OK, it looks like I'm +missing one slide. + +Can I cheat a little +from here? + +OK. + +So now that we dealt with the +time until the first arrival, + +we can start talking about +the time until the second + +arrival, and so on. + +How do we define these? + +After the first arrival happens, +we're going to have a + +sequence of time slots with no +arrivals, and then the next + +arrival is going to happen. + +So we call this time +that elapses-- + +or number of time slots after +the first arrival + +until the next one-- + +we call it T2. + +This is the second inter-arrival +time, that is, + +time between arrivals. + +Once this arrival has happened, +then we wait and see + +how many more it takes until +the third arrival. + +And we call this +time here, T3. + +We're interested in the time of +the k-th arrival, which is + +going to be just the +sum of the first k + +inter-arrival times. + +So for example, let's say Y3 +is the time that the third + +arrival comes. + +Y3 is just the sum of T1, +plus T2, plus T3. + +So we're interested in this +random variable, Y3, and it's + +the sum of inter-arrival +times. + +To understand what kind of +random variable it is, I guess + +we should understand what kind +of random variables these are + +going to be. + +So what kind of random +variable is T2? + +Your sister is doing her coin +flips until a success is + +observed for the first time. + +Based on that information about +what has happened so + +far, you are called +into the room. + +And you start watching until a +success is observed again. + +So after you start watching, +what you have is just a + +sequence of independent +Bernoulli trials. + +So each one of these +has probability + +p of being a success. + +The time it's going to take +until the first success, this + +number, T2, is going to be again +just another geometric + +random variable. + +It's as if the process +just started. + +After you are called into the +room, you have no foresight, + +you don't have any information +about the future, other than + +the fact that these +are going to be + +independent Bernoulli trials. + +So T2 itself is going to be +geometric with the same + +parameter p. + +And then you can continue the +arguments and argue that T3 is + +also geometric with the +same parameter p. + +Furthermore, whatever happened, +how long it took + +until you were called in, it +doesn't change the statistics + +about what's going to happen +in the future. + +So whatever happens +in the future is + +independent from the past. + +So T1, T2, and T3 are +independent random variables. + +So conclusion is that the time +until the third arrival is the + +sum of 3 independent geometric +random variables, with the + +same parameter. + +And this is true +more generally. + +The time until the k-th arrival +is going to be the sum + +of k independent random +variables. + +So in general, Yk is going to be +T1 plus Tk, where the Ti's + +are geometric, with the same +parameter p, and independent. + +So now what's more natural +than trying to find the + +distribution of the random +variable Yk? + +How can we find it? + +So I fixed k for you. + +Let's say k is 100. + +I'm interested in how +long it takes until + +100 customers arrive. + +How can we find the distribution +of Yk? + +Well one way of doing +it is to use this + +lovely convolution formula. + +Take a geometric, convolve it +with another geometric, you + +get something. + +Take that something that you +got, convolve it with a + +geometric once more, do this 99 +times, and this gives you + +the distribution of Yk. + +So that's definitely doable, +and it's extremely tedious. + +Let's try to find +the distribution + +of Yk using a shortcut. + +So the probability that +Yk is equal to t. + +So we're trying to find +the PMF of Yk. + +k has been fixed for us. + +And we want to calculate this +probability for the various + +values of t, because this +is going to give + +us the PMF of Yk. + +OK. + +What is this event? + +What does it take for the k-th +arrival to be at time t? + +For that to happen, we +need two things. + +In the first t -1 slots, +how many arrivals + +should we have gotten? + +k - 1. + +And then in the last slot, we +get one more arrival, and + +that's the k-th one. + +So this is the probability that +we have k - 1 arrivals in + +the time interval +from 1 up to t. + +And then, an arrival +at time t. + +That's the only way that it +can happen, that the k-th + +arrival happens at time t. + +We need to have an arrival +at time t. + +And before that time, +we need to have + +exactly k - 1 arrivals. + +Now this is an event +that refers-- + +t-1. + +In the previous time slots we +had exactly k -1 arrivals. + +And then at the last time slot +we get one more arrival. + +Now the interesting thing is +that this event here has to do + +with what happened from time +1 up to time t -1. + +This event has to do with +what happened at time t. + +Different time slots are +independent of each other. + +So this event and that event +are independent. + +So this means that we can +multiply their probabilities. + +So take the probability +of this. + +What is that? + +Well probability of having a +certain number of arrivals in + +a certain number of time slots, +these are just the + +binomial probabilities. + +So this is, out of t - 1 slots, +to get exactly k - 1 + +arrivals, p to the k-1, (1-p) +to the t-1 - (k-1), + +this gives us t-k. + +And then we multiply with this +probability, the probability + +of an arrival, at time +t is equal to p. + +And so this is the formula for +the PMF of the number-- + +of the time it takes until +the k-th arrival happens. + +Does it agree with the formula +in your handout? + +Or its not there? + +It's not there. + +OK. + +Yeah. + +OK. + +So that's the formula and it is +true for what values of t? + +[INAUDIBLE]. + +It takes at least k time slots +in order to get k arrivals, so + +this formula should be +true for k larger + +than or equal to t. + +For t larger than +or equal to k. + +All right. + +So this gives us the PMF of +the random variable Yk. + +Of course, we may also be +interested in the mean and + +variance of Yk. + +But this is a lot easier. + +Since Yk is the sum of +independent random variables, + +the expected value of Yk is +going to be just k times the + +expected value of +your typical t. + +So the expected value of Yk is +going to be just k times 1/p, + +which is the mean of +the geometric. + +And similarly for the variance, +it's going to be k + +times the variance +of a geometric. + +So we have everything there is +to know about the distribution + +of how long it takes until +the first arrival comes. + +OK. + +Finally, let's do a few +more things about + +the Bernoulli process. + +It's interesting to talk about +several processes at the time. + +So in the situation here of +splitting a Bernoulli process + +is where you have arrivals +that come to a server. + +And that's a picture of which +slots get arrivals. + +But actually maybe you +have two servers. + +And whenever an arrival comes to +the system, you flip a coin + +and with some probability, q, +you send it to one server. + +And with probability 1-q, you +send it to another server. + +So there is a single +arrival stream, but + +two possible servers. + +And whenever there's an arrival, +you either send it + +here or you send it there. + +And each time you decide where +you send it by flipping an + +independent coin that +has its own bias q. + +The coin flips that decide +where do you send it are + +assumed to be independent from +the arrival process itself. + +So there's two coin flips +that are happening. + +At each time slot, there's a +coin flip that decides whether + +you have an arrival in this +process here, and that coin + +flip is with parameter p. + +And if you have something that +arrives, you flip another coin + +with probabilities q, and 1-q, +that decides whether you send + +it up there or you send +it down there. + +So what kind of arrival process +does this server see? + +At any given time slot, there's +probability p that + +there's an arrival here. + +And there's a further +probability q that this + +arrival gets sent up there. + +So the probability that this +server sees an arrival at any + +given time is p times q. + +So this process here is going to +be a Bernoulli process, but + +with a different parameter, +p times q. + +And this one down here, with the +same argument, is going to + +be Bernoulli with parameter +p times (1-q). + +So by taking a Bernoulli +stream of arrivals and + +splitting it into +two, you get two + +separate Bernoulli processes. + +This is going to be a Bernoulli +process, that's + +going to be a Bernoulli +process. + +Well actually, I'm running +a little too fast. + +What does it take to verify that +it's a Bernoulli process? + +At each time slot, +it's a 0 or 1. + +And it's going to be a 1, you're +going to see an arrival + +with probability p times q. + +What else do we need to verify, +to be able to tell-- + +to say that it's a Bernoulli +process? + +We need to make sure that +whatever happens in this + +process, in different time +slots, are statistically + +independent from each other. + +Is that property true? + +For example, what happens in +this time slot whether you got + +an arrival or not, is it +independent from what happened + +at that time slot? + +The answer is yes for the +following reason. + +What happens in this time slot +has to do with the coin flip + +associated with the original +process at this time, and the + +coin flip that decides +where to send things. + +What happens at that time slot +has to do with the coin flip + +here, and the additional coin +flip that decides where to + +send it if something came. + +Now all these coin flips are +independent of each other. + +The coin flips that determine +whether we have an arrival + +here is independent from the +coin flips that determined + +whether we had an +arrival there. + +And you can generalize this +argument and conclude that, + +indeed, every time slot here +is independent from + +any other time slot. + +And this does make it +a Bernoulli process. + +And the reason is that, in the +original process, every time + +slot is independent from +every other time slot. + +And the additional assumption +that the coin flips that we're + +using to decide where to send +things, these are also + +independent of each other. + +So we're using here the basic +property that functions of + +independent things remain +independent. + +There's a converse +picture of this. + +Instead of taking one stream +and splitting it into two + +streams, you can do +the opposite. + +You could start from two +streams of arrivals. + +Let's say you have arrivals of +men and you have arrivals of + +women, but you don't +care about gender. + +And the only thing you record +is whether, in a given time + +slot, you had an +arrival or not. + +Notice that here we may have +an arrival of a man and the + +arrival of a woman. + +We just record it with a 1, by +saying there was an arrival. + +So in the merged process, we're +not keeping track of how + +many arrivals we had total. + +We just record whether +there was an + +arrival or not an arrival. + +So an arrival gets recorded here +if, and only if, one or + +both of these streams +had an arrival. + +So that we call a merging +of two Bernoull-- of two + +processes, of two arrival +processes. + +So let's make the assumption +that this arrival process is + +independent from that +arrival process. + +So what happens at the +typical slot here? + +I'm going to see an arrival, +unless none of + +these had an arrival. + +So the probability of an arrival +in a typical time slot + +is going to be 1 minus the +probability of no arrival. + +And the event of no arrival +corresponds to the first + +process having no arrival, +and the second + +process having no arrival. + +So there's no arrival in the +merged process if, and only + +if, there's no arrival in the +first process and no arrival + +in the second process. + +We're assuming that the two +processes are independent and + +that's why we can multiply +probabilities here. + +And then you can take this +formula and it simplifies to p + ++ q, minus p times q. + +So each time slot of the merged +process has a certain + +probability of seeing +an arrival. + +Is the merged process +a Bernoulli process? + +Yes, it is after you verify the +additional property that + +different slots are independent +of each other. + +Why are they independent? + +What happens in this slot has to +do with that slot, and that + +slot down here. + +These two slots-- + +so what happens here, +has to do with what + +happens here and there. + +What happens in this slot has +to do with whatever happened + +here and there. + +Now, whatever happens here and +there is independent from + +whatever happens +here and there. + +Therefore, what happens here +is independent from what + +happens there. + +So the independence property +is preserved. + +The different slots of this +merged process are independent + +of each other. + +So the merged process is itself +a Bernoulli process. + +So please digest these two +pictures of merging and + +splitting, because we're going +to revisit them in continuous + +time where things are little +subtler than that. + +OK. + +Good luck on the exam and +see you in a week. \ No newline at end of file diff --git a/hSRcHTafkjE.txt b/hSRcHTafkjE.txt new file mode 100644 index 0000000000000000000000000000000000000000..4124013c155b841d232de0dd790d80a29632848a --- /dev/null +++ b/hSRcHTafkjE.txt @@ -0,0 +1,1747 @@ +align:start position:0% + +hi everyone welcome back so today I'd + + align:start position:0% +hi everyone welcome back so today I'd + + + align:start position:0% +hi everyone welcome back so today I'd +like to tackle a problem on pseudo + + align:start position:0% +like to tackle a problem on pseudo + + + align:start position:0% +like to tackle a problem on pseudo +inverses so given a matrix a which is + + align:start position:0% +inverses so given a matrix a which is + + + align:start position:0% +inverses so given a matrix a which is +not square so it's just 1 & 2 + + align:start position:0% +not square so it's just 1 & 2 + + + align:start position:0% +not square so it's just 1 & 2 +first what is it pseudo inverse so a + + align:start position:0% +first what is it pseudo inverse so a + + + align:start position:0% +first what is it pseudo inverse so a +plus I'm using to denote the pseudo + + align:start position:0% +plus I'm using to denote the pseudo + + + align:start position:0% +plus I'm using to denote the pseudo +inverse then secondly compute a plus a + + align:start position:0% +inverse then secondly compute a plus a + + + align:start position:0% +inverse then secondly compute a plus a +and a a plus and then thirdly if X is in + + align:start position:0% +and a a plus and then thirdly if X is in + + + align:start position:0% +and a a plus and then thirdly if X is in +the null space of a what is a plus a + + align:start position:0% +the null space of a what is a plus a + + + align:start position:0% +the null space of a what is a plus a +acting on X and lastly if X is in the + + align:start position:0% +acting on X and lastly if X is in the + + + align:start position:0% +acting on X and lastly if X is in the +column space of a transpose what is a + + align:start position:0% +column space of a transpose what is a + + + align:start position:0% +column space of a transpose what is a +plus ax so I'll let you think about this + + align:start position:0% +plus ax so I'll let you think about this + + + align:start position:0% +plus ax so I'll let you think about this +problem for a bit and I'll be back in a + + align:start position:0% +problem for a bit and I'll be back in a + + + align:start position:0% +problem for a bit and I'll be back in a +second + + align:start position:0% + + + + align:start position:0% + +hi everyone welcome back okay so let's + + align:start position:0% +hi everyone welcome back okay so let's + + + align:start position:0% +hi everyone welcome back okay so let's +take a look at this problem now first + + align:start position:0% +take a look at this problem now first + + + align:start position:0% +take a look at this problem now first +off what is the pseudo inverse well + + align:start position:0% +off what is the pseudo inverse well + + + align:start position:0% +off what is the pseudo inverse well +we define the pseudo inverse using the + + align:start position:0% +we define the pseudo inverse using the + + + align:start position:0% +we define the pseudo inverse using the +SVD so in actuality this is nothing new + + align:start position:0% + + + + align:start position:0% + +now we note that because a is not square + + align:start position:0% +now we note that because a is not square + + + align:start position:0% +now we note that because a is not square +the regular inverse of a doesn't + + align:start position:0% +the regular inverse of a doesn't + + + align:start position:0% +the regular inverse of a doesn't +necessarily exist however we do know + + align:start position:0% +necessarily exist however we do know + + + align:start position:0% +necessarily exist however we do know +that the SVD exists for every matrix a + + align:start position:0% +that the SVD exists for every matrix a + + + align:start position:0% +that the SVD exists for every matrix a +whether it's rectangular or not or sorry + + align:start position:0% +whether it's rectangular or not or sorry + + + align:start position:0% +whether it's rectangular or not or sorry +whether it's square or not so how do we + + align:start position:0% +whether it's square or not so how do we + + + align:start position:0% +whether it's square or not so how do we +compute the SVD of a matrix well let's + + align:start position:0% +compute the SVD of a matrix well let's + + + align:start position:0% +compute the SVD of a matrix well let's +just recall that the SVD of a matrix has + + align:start position:0% +just recall that the SVD of a matrix has + + + align:start position:0% +just recall that the SVD of a matrix has +the form of u Sigma V transpose where u + + align:start position:0% +the form of u Sigma V transpose where u + + + align:start position:0% +the form of u Sigma V transpose where u +and V are orthogonal matrices and Sigma + + align:start position:0% +and V are orthogonal matrices and Sigma + + + align:start position:0% +and V are orthogonal matrices and Sigma +is a matrix with positive values along + + align:start position:0% +is a matrix with positive values along + + + align:start position:0% +is a matrix with positive values along +the diagonal or a zeroes along the + + align:start position:0% +the diagonal or a zeroes along the + + + align:start position:0% +the diagonal or a zeroes along the +diagonal and let's just take a look at + + align:start position:0% +diagonal and let's just take a look at + + + align:start position:0% +diagonal and let's just take a look at +the dimensions of these matrices for a + + align:start position:0% +the dimensions of these matrices for a + + + align:start position:0% +the dimensions of these matrices for a +second so we know that a is a 1 by 2 + + align:start position:0% +second so we know that a is a 1 by 2 + + + align:start position:0% +second so we know that a is a 1 by 2 +matrix and the way to figure out what + + align:start position:0% +matrix and the way to figure out what + + + align:start position:0% +matrix and the way to figure out what +the dimensions of these matrices are I + + align:start position:0% +the dimensions of these matrices are I + + + align:start position:0% +the dimensions of these matrices are I +usually always start with the center + + align:start position:0% +usually always start with the center + + + align:start position:0% +usually always start with the center +matrix Sigma and Sigma is always going + + align:start position:0% +matrix Sigma and Sigma is always going + + + align:start position:0% +matrix Sigma and Sigma is always going +to have the same dimensions as a so it's + + align:start position:0% +to have the same dimensions as a so it's + + + align:start position:0% +to have the same dimensions as a so it's +going to be a 1 by 2 matrix U and V are + + align:start position:0% +going to be a 1 by 2 matrix U and V are + + + align:start position:0% +going to be a 1 by 2 matrix U and V are +always square matrices so to make this + + align:start position:0% +always square matrices so to make this + + + align:start position:0% +always square matrices so to make this +multiplication work out + + align:start position:0% +multiplication work out + + + align:start position:0% +multiplication work out +we need V to have 2 and because it's + + align:start position:0% +we need V to have 2 and because it's + + + align:start position:0% +we need V to have 2 and because it's +square it has to be 2 by 2 and likewise + + align:start position:0% +square it has to be 2 by 2 and likewise + + + align:start position:0% +square it has to be 2 by 2 and likewise +u has to be 1 by 1 so we now have the + + align:start position:0% +u has to be 1 by 1 so we now have the + + + align:start position:0% +u has to be 1 by 1 so we now have the +dimensions of u Sigma and V and note + + align:start position:0% +dimensions of u Sigma and V and note + + + align:start position:0% +dimensions of u Sigma and V and note +because Sigma herb because use a 1 by 1 + + align:start position:0% +because Sigma herb because use a 1 by 1 + + + align:start position:0% +because Sigma herb because use a 1 by 1 +matrix + + align:start position:0% +matrix + + + align:start position:0% +matrix +the only orthogonal 1 by 1 matrix is + + align:start position:0% +the only orthogonal 1 by 1 matrix is + + + align:start position:0% +the only orthogonal 1 by 1 matrix is +just 1 so u we already know is just + + align:start position:0% +just 1 so u we already know is just + + + align:start position:0% +just 1 so u we already know is just +going to be the matrix the identity + + align:start position:0% +going to be the matrix the identity + + + align:start position:0% +going to be the matrix the identity +matrix which is a 1 by 1 matrix ok now + + align:start position:0% +matrix which is a 1 by 1 matrix ok now + + + align:start position:0% +matrix which is a 1 by 1 matrix ok now +how do we compute V and Sigma well + + align:start position:0% + + + + align:start position:0% + +we can take a transpose an a and if we + + align:start position:0% +we can take a transpose an a and if we + + + align:start position:0% +we can take a transpose an a and if we +do that we end up getting the matrix V + + align:start position:0% +do that we end up getting the matrix V + + + align:start position:0% +do that we end up getting the matrix V +Sigma AI transpose Sigma V transpose and + + align:start position:0% +Sigma AI transpose Sigma V transpose and + + + align:start position:0% +Sigma AI transpose Sigma V transpose and +this matrix is going to be a square + + align:start position:0% +this matrix is going to be a square + + + align:start position:0% +this matrix is going to be a square +matrix where the diagonal elements are + + align:start position:0% +matrix where the diagonal elements are + + + align:start position:0% +matrix where the diagonal elements are +squares of the singular values so + + align:start position:0% +squares of the singular values so + + + align:start position:0% +squares of the singular values so +computing V and the values along Sigma + + align:start position:0% +computing V and the values along Sigma + + + align:start position:0% +computing V and the values along Sigma +just boil down to diagonalizing a + + align:start position:0% +just boil down to diagonalizing a + + + align:start position:0% +just boil down to diagonalizing a +transpose a so what is a transpose a + + align:start position:0% +transpose a so what is a transpose a + + + align:start position:0% +transpose a so what is a transpose a +well in our case it's 1/2 times 1/2 + + align:start position:0% +well in our case it's 1/2 times 1/2 + + + align:start position:0% +well in our case it's 1/2 times 1/2 +which gives us 1/2 to 4 and note that + + align:start position:0% +which gives us 1/2 to 4 and note that + + + align:start position:0% +which gives us 1/2 to 4 and note that +the second row is just a constant + + align:start position:0% +the second row is just a constant + + + align:start position:0% +the second row is just a constant +multiple times the first row now what + + align:start position:0% +multiple times the first row now what + + + align:start position:0% +multiple times the first row now what +this means is we have a zero eigen value + + align:start position:0% +this means is we have a zero eigen value + + + align:start position:0% +this means is we have a zero eigen value +so we already know that lambda one is + + align:start position:0% +so we already know that lambda one is + + + align:start position:0% +so we already know that lambda one is +going to be zero so one of the + + align:start position:0% +going to be zero so one of the + + + align:start position:0% +going to be zero so one of the +eigenvalues of this matrix is zero and + + align:start position:0% +eigenvalues of this matrix is zero and + + + align:start position:0% +eigenvalues of this matrix is zero and +of course when we square root it this is + + align:start position:0% +of course when we square root it this is + + + align:start position:0% +of course when we square root it this is +going to give us a singular value Sigma + + align:start position:0% +going to give us a singular value Sigma + + + align:start position:0% +going to give us a singular value Sigma +which is also zero and this this is + + align:start position:0% +which is also zero and this this is + + + align:start position:0% +which is also zero and this this is +generally a case when we have a sigma + + align:start position:0% +generally a case when we have a sigma + + + align:start position:0% +generally a case when we have a sigma +which is not square we typically always + + align:start position:0% +which is not square we typically always + + + align:start position:0% +which is not square we typically always +have zero singular values now to compute + + align:start position:0% +have zero singular values now to compute + + + align:start position:0% +have zero singular values now to compute +the second eigen value well we already + + align:start position:0% +the second eigen value well we already + + + align:start position:0% +the second eigen value well we already +know how to compute the eigenvalues of a + + align:start position:0% +know how to compute the eigenvalues of a + + + align:start position:0% +know how to compute the eigenvalues of a +matrix so I'm just going to tell you + + align:start position:0% +matrix so I'm just going to tell you + + + align:start position:0% +matrix so I'm just going to tell you +what it is the second one is lambdas 5 + + align:start position:0% +what it is the second one is lambdas 5 + + + align:start position:0% +what it is the second one is lambdas 5 +and if we just take a quick look what + + align:start position:0% +and if we just take a quick look what + + + align:start position:0% +and if we just take a quick look what +the corresponding eigenvector is going + + align:start position:0% +the corresponding eigenvector is going + + + align:start position:0% +the corresponding eigenvector is going +to be two lambdas 5 it's going to + + align:start position:0% +to be two lambdas 5 it's going to + + + align:start position:0% +to be two lambdas 5 it's going to +satisfy this equation so we can take the + + align:start position:0% +satisfy this equation so we can take the + + + align:start position:0% +satisfy this equation so we can take the +eigen vector U to be 1 and 2 however + + align:start position:0% +eigen vector U to be 1 and 2 however + + + align:start position:0% +eigen vector U to be 1 and 2 however +remember that when we compute the eigen + + align:start position:0% +remember that when we compute the eigen + + + align:start position:0% +remember that when we compute the eigen +vectors for this orthogonal matrix V + + align:start position:0% +vectors for this orthogonal matrix V + + + align:start position:0% +vectors for this orthogonal matrix V +they always have to have a unit length + + align:start position:0% +they always have to have a unit length + + + align:start position:0% +they always have to have a unit length +and this vector right now it doesn't + + align:start position:0% +and this vector right now it doesn't + + + align:start position:0% +and this vector right now it doesn't +have a unit length we have to divide by + + align:start position:0% +have a unit length we have to divide by + + + align:start position:0% +have a unit length we have to divide by +the + + align:start position:0% +the + + + align:start position:0% +the +length of this vector which in our case + + align:start position:0% +length of this vector which in our case + + + align:start position:0% +length of this vector which in our case +is 1 over root 5 and if I go back to the + + align:start position:0% +is 1 over root 5 and if I go back to the + + + align:start position:0% +is 1 over root 5 and if I go back to the +land equals 0 case but we also have + + align:start position:0% +land equals 0 case but we also have + + + align:start position:0% +land equals 0 case but we also have +another eigenvector which I'll just + + align:start position:0% +another eigenvector which I'll just + + + align:start position:0% +another eigenvector which I'll just +state you can actually compute it quite + + align:start position:0% +state you can actually compute it quite + + + align:start position:0% +state you can actually compute it quite +quickly just by noting that it has to be + + align:start position:0% +quickly just by noting that it has to be + + + align:start position:0% +quickly just by noting that it has to be +orthogonal to this eigenvector 2 and 1 + + align:start position:0% +orthogonal to this eigenvector 2 and 1 + + + align:start position:0% +orthogonal to this eigenvector 2 and 1 +ok so what this means is a has a + + align:start position:0% +ok so what this means is a has a + + + align:start position:0% +ok so what this means is a has a +singular value decomposition which looks + + align:start position:0% +singular value decomposition which looks + + + align:start position:0% +singular value decomposition which looks +like 1 so this is U times Sigma which is + + align:start position:0% +like 1 so this is U times Sigma which is + + + align:start position:0% +like 1 so this is U times Sigma which is +going to be root 5 0 remember that the + + align:start position:0% +going to be root 5 0 remember that the + + + align:start position:0% +going to be root 5 0 remember that the +first Sigma is actually the square root + + align:start position:0% +first Sigma is actually the square root + + + align:start position:0% +first Sigma is actually the square root +of the eigenvalue times a matrix which + + align:start position:0% +of the eigenvalue times a matrix which + + + align:start position:0% +of the eigenvalue times a matrix which +looks like now we have to order the + + align:start position:0% +looks like now we have to order the + + + align:start position:0% +looks like now we have to order the +eigenvalues up in the correct order + + align:start position:0% +eigenvalues up in the correct order + + + align:start position:0% +eigenvalues up in the correct order +because 5 appears in the first column we + + align:start position:0% +because 5 appears in the first column we + + + align:start position:0% +because 5 appears in the first column we +have to take this vector to be in the + + align:start position:0% +have to take this vector to be in the + + + align:start position:0% +have to take this vector to be in the +first column as well so this is 1 over + + align:start position:0% +first column as well so this is 1 over + + + align:start position:0% +first column as well so this is 1 over +root 5 this is 2 over root 5 negative 2 + + align:start position:0% +root 5 this is 2 over root 5 negative 2 + + + align:start position:0% +root 5 this is 2 over root 5 negative 2 +over root 5 and 1 over root 5 and now + + align:start position:0% +over root 5 and 1 over root 5 and now + + + align:start position:0% +over root 5 and 1 over root 5 and now +this is V but the singular value is + + align:start position:0% +this is V but the singular value is + + + align:start position:0% +this is V but the singular value is +featured the singular value + + align:start position:0% +featured the singular value + + + align:start position:0% +featured the singular value +decomposition is defined by a V + + align:start position:0% +decomposition is defined by a V + + + align:start position:0% +decomposition is defined by a V +transpose okay so this gives us a + + align:start position:0% +transpose okay so this gives us a + + + align:start position:0% +transpose okay so this gives us a +representation for a and now once we + + align:start position:0% +representation for a and now once we + + + align:start position:0% +representation for a and now once we +have the SVD of a how do we actually + + align:start position:0% +have the SVD of a how do we actually + + + align:start position:0% +have the SVD of a how do we actually +compute a plus or the pseudo inverse of + + align:start position:0% +compute a plus or the pseudo inverse of + + + align:start position:0% +compute a plus or the pseudo inverse of +a well just note if a was invertible + + align:start position:0% +a well just note if a was invertible + + + align:start position:0% +a well just note if a was invertible +then the inverse of a in terms of the + + align:start position:0% +then the inverse of a in terms of the + + + align:start position:0% +then the inverse of a in terms of the +SVD would be the transpose times the + + align:start position:0% +SVD would be the transpose times the + + + align:start position:0% +SVD would be the transpose times the +inverse of Sigma + + align:start position:0% +inverse of Sigma + + + align:start position:0% +inverse of Sigma +oh sorry this is not V transpose this is + + align:start position:0% +oh sorry this is not V transpose this is + + + align:start position:0% +oh sorry this is not V transpose this is +just V so it'd be V Sigma inverse u + + align:start position:0% +just V so it'd be V Sigma inverse u + + + align:start position:0% +just V so it'd be V Sigma inverse u +transpose and when when a is invertible + + align:start position:0% +transpose and when when a is invertible + + + align:start position:0% +transpose and when when a is invertible +Sigma inverse exists so in our case a + + align:start position:0% +Sigma inverse exists so in our case a + + + align:start position:0% +Sigma inverse exists so in our case a +Sigma inverse doesn't necessarily exist + + align:start position:0% +Sigma inverse doesn't necessarily exist + + + align:start position:0% +Sigma inverse doesn't necessarily exist +because Sigma note this is Sigma Sigma + + align:start position:0% +because Sigma note this is Sigma Sigma + + + align:start position:0% +because Sigma note this is Sigma Sigma +is root 5 and 0 so we have to construct + + align:start position:0% +is root 5 and 0 so we have to construct + + + align:start position:0% +is root 5 and 0 so we have to construct +an a pseudo inverse for Sigma so the way + + align:start position:0% +an a pseudo inverse for Sigma so the way + + + align:start position:0% +an a pseudo inverse for Sigma so the way +that we do that is we take one over each + + align:start position:0% +that we do that is we take one over each + + + align:start position:0% +that we do that is we take one over each +singular value and we take the transpose + + align:start position:0% +singular value and we take the transpose + + + align:start position:0% +singular value and we take the transpose +of Sigma so when a is not invertible we + + align:start position:0% +of Sigma so when a is not invertible we + + + align:start position:0% +of Sigma so when a is not invertible we +can still construct a pseudo inverse by + + align:start position:0% +can still construct a pseudo inverse by + + + align:start position:0% +can still construct a pseudo inverse by +taking V Sigma and approximation for + + align:start position:0% +taking V Sigma and approximation for + + + align:start position:0% +taking V Sigma and approximation for +Sigma inverse which in our case is going + + align:start position:0% +Sigma inverse which in our case is going + + + align:start position:0% +Sigma inverse which in our case is going +to be 1 over the singular value and 0 so + + align:start position:0% +to be 1 over the singular value and 0 so + + + align:start position:0% +to be 1 over the singular value and 0 so +note how where Sigma is invertible we + + align:start position:0% +note how where Sigma is invertible we + + + align:start position:0% +note how where Sigma is invertible we +take the inverse and then we fill in + + align:start position:0% +take the inverse and then we fill in + + + align:start position:0% +take the inverse and then we fill in +zeros in the other areas + + align:start position:0% +zeros in the other areas + + + align:start position:0% +zeros in the other areas +times u transpose and we can work this + + align:start position:0% +times u transpose and we can work this + + + align:start position:0% +times u transpose and we can work this +out we get 1 over root 5 1 minus 2 2 1 1 + + align:start position:0% + + + + align:start position:0% + +over root 5 0 + + align:start position:0% + + + + align:start position:0% + +and if I multiply things out + + align:start position:0% +and if I multiply things out + + + align:start position:0% +and if I multiply things out +I get 1/5 1 2 okay so this is an + + align:start position:0% +I get 1/5 1 2 okay so this is an + + + align:start position:0% +I get 1/5 1 2 okay so this is an +approximation for a inverse which is the + + align:start position:0% +approximation for a inverse which is the + + + align:start position:0% +approximation for a inverse which is the +pseudo inverse okay so this finishes up + + align:start position:0% +pseudo inverse okay so this finishes up + + + align:start position:0% +pseudo inverse okay so this finishes up +part 1 and I'll start on part 2 in a + + align:start position:0% +part 1 and I'll start on part 2 in a + + + align:start position:0% +part 1 and I'll start on part 2 in a +second + + align:start position:0% + + + + align:start position:0% + +okay so now that we've just computed a + + align:start position:0% +okay so now that we've just computed a + + + align:start position:0% +okay so now that we've just computed a +plus the pseudo inverse of a we're gonna + + align:start position:0% +plus the pseudo inverse of a we're gonna + + + align:start position:0% +plus the pseudo inverse of a we're gonna +investigate some properties of the + + align:start position:0% +investigate some properties of the + + + align:start position:0% +investigate some properties of the +pseudo inverse okay so for part two we + + align:start position:0% +pseudo inverse okay so for part two we + + + align:start position:0% +pseudo inverse okay so for part two we +need to compute a times a plus and a + + align:start position:0% +need to compute a times a plus and a + + + align:start position:0% +need to compute a times a plus and a +plus times a okay so we can just go + + align:start position:0% +plus times a okay so we can just go + + + align:start position:0% +plus times a okay so we can just go +ahead and do this so a a plus can do + + align:start position:0% +ahead and do this so a a plus can do + + + align:start position:0% +ahead and do this so a a plus can do +fairly quickly fifth one two and when we + + align:start position:0% +fairly quickly fifth one two and when we + + + align:start position:0% +fairly quickly fifth one two and when we +multiply it out we get one plus four + + align:start position:0% +multiply it out we get one plus four + + + align:start position:0% +multiply it out we get one plus four +divided by 5 is 1 so we just get the one + + align:start position:0% +divided by 5 is 1 so we just get the one + + + align:start position:0% +divided by 5 is 1 so we just get the one +by one matrix which is 1 the identity + + align:start position:0% +by one matrix which is 1 the identity + + + align:start position:0% +by one matrix which is 1 the identity +matrix + + align:start position:0% +matrix + + + align:start position:0% +matrix +and secondly if we take a plus times a + + align:start position:0% +and secondly if we take a plus times a + + + align:start position:0% +and secondly if we take a plus times a +we're going to get 1/5 1/2 times 1/2 and + + align:start position:0% +we're going to get 1/5 1/2 times 1/2 and + + + align:start position:0% +we're going to get 1/5 1/2 times 1/2 and +we can just fill in this matrix just 1/5 + + align:start position:0% +we can just fill in this matrix just 1/5 + + + align:start position:0% +we can just fill in this matrix just 1/5 +1 2 2 1 ok and this concludes part two + + align:start position:0% +1 2 2 1 ok and this concludes part two + + + align:start position:0% +1 2 2 1 ok and this concludes part two +so now let's take a look at what happens + + align:start position:0% +so now let's take a look at what happens + + + align:start position:0% +so now let's take a look at what happens +when a vector X is in the null space of + + align:start position:0% +when a vector X is in the null space of + + + align:start position:0% +when a vector X is in the null space of +a and then secondly what happens that + + align:start position:0% +a and then secondly what happens that + + + align:start position:0% +a and then secondly what happens that +when X is in the column space of a + + align:start position:0% +when X is in the column space of a + + + align:start position:0% +when X is in the column space of a +transpose so for part three let's assume + + align:start position:0% +transpose so for part three let's assume + + + align:start position:0% +transpose so for part three let's assume +X is in the null space of a well what's + + align:start position:0% +X is in the null space of a well what's + + + align:start position:0% +X is in the null space of a well what's +the null space of a we can quickly check + + align:start position:0% +the null space of a we can quickly check + + + align:start position:0% +the null space of a we can quickly check +that the null space of a is a constant + + align:start position:0% +that the null space of a is a constant + + + align:start position:0% +that the null space of a is a constant +times any vector minus 2 1 okay so + + align:start position:0% +times any vector minus 2 1 okay so + + + align:start position:0% +times any vector minus 2 1 okay so +that's the null space so if X is for + + align:start position:0% +that's the null space so if X is for + + + align:start position:0% +that's the null space so if X is for +example ie if we take X is equal to + + align:start position:0% +example ie if we take X is equal to + + + align:start position:0% +example ie if we take X is equal to +minus 2 1 + + align:start position:0% + + + + align:start position:0% + +and we were to say multiply it by a plus + + align:start position:0% +and we were to say multiply it by a plus + + + align:start position:0% +and we were to say multiply it by a plus +a acting on X we see that we get zero + + align:start position:0% +a acting on X we see that we get zero + + + align:start position:0% +a acting on X we see that we get zero +and this isn't very surprising because + + align:start position:0% +and this isn't very surprising because + + + align:start position:0% +and this isn't very surprising because +well if X is in the null space of a we + + align:start position:0% +well if X is in the null space of a we + + + align:start position:0% +well if X is in the null space of a we +know that a acting on X is going to be + + align:start position:0% +know that a acting on X is going to be + + + align:start position:0% +know that a acting on X is going to be +zero so that no matter what matrix a + + align:start position:0% +zero so that no matter what matrix a + + + align:start position:0% +zero so that no matter what matrix a +plus is when we multiply by zero we'll + + align:start position:0% +plus is when we multiply by zero we'll + + + align:start position:0% +plus is when we multiply by zero we'll +always end up with zero okay and then + + align:start position:0% +always end up with zero okay and then + + + align:start position:0% +always end up with zero okay and then +lastly let's take a look at the column + + align:start position:0% +lastly let's take a look at the column + + + align:start position:0% +lastly let's take a look at the column +space of a transpose + + align:start position:0% + + + + align:start position:0% + +well a transpose is one two so it's any + + align:start position:0% +well a transpose is one two so it's any + + + align:start position:0% +well a transpose is one two so it's any +constant times the vector one two and + + align:start position:0% +constant times the vector one two and + + + align:start position:0% +constant times the vector one two and +specifically if we were to take say X is + + align:start position:0% +specifically if we were to take say X is + + + align:start position:0% +specifically if we were to take say X is +equal to one two we can work out a plus + + align:start position:0% +equal to one two we can work out a plus + + + align:start position:0% +equal to one two we can work out a plus +a acting on the vector 1 2 so we have + + align:start position:0% +a acting on the vector 1 2 so we have + + + align:start position:0% +a acting on the vector 1 2 so we have +1/5 1 2 2 1 + + align:start position:0% +1/5 1 2 2 1 + + + align:start position:0% +1/5 1 2 2 1 +so recall this is a plus a and if we + + align:start position:0% +so recall this is a plus a and if we + + + align:start position:0% +so recall this is a plus a and if we +multiply it on the vector 1 2 we get 1 + + align:start position:0% +multiply it on the vector 1 2 we get 1 + + + align:start position:0% +multiply it on the vector 1 2 we get 1 +plus 4 is 5 divided by 5 so we get 1 2 + + align:start position:0% +plus 4 is 5 divided by 5 so we get 1 2 + + + align:start position:0% +plus 4 is 5 divided by 5 so we get 1 2 +plus 2 is 4 + + align:start position:0% +plus 2 is 4 + + + align:start position:0% + +oh sorry I copied the matrix down so + + align:start position:0% +oh sorry I copied the matrix down so + + + align:start position:0% +oh sorry I copied the matrix down so +it's 2 plus 8 which is 10 divided by 5 + + align:start position:0% +it's 2 plus 8 which is 10 divided by 5 + + + align:start position:0% +it's 2 plus 8 which is 10 divided by 5 +is 2 and we see that at the end we + + align:start position:0% +is 2 and we see that at the end we + + + align:start position:0% +is 2 and we see that at the end we +recover the vector X so in general if we + + align:start position:0% +recover the vector X so in general if we + + + align:start position:0% +recover the vector X so in general if we +take a plus a acting on X where X is in + + align:start position:0% +take a plus a acting on X where X is in + + + align:start position:0% +take a plus a acting on X where X is in +the column space of a transpose + + align:start position:0% +the column space of a transpose + + + align:start position:0% +the column space of a transpose +we always recover X + + align:start position:0% +we always recover X + + + align:start position:0% +we always recover X +the end of the day so intuitively what + + align:start position:0% +the end of the day so intuitively what + + + align:start position:0% +the end of the day so intuitively what +is this matrix a plus a do well if X is + + align:start position:0% +is this matrix a plus a do well if X is + + + align:start position:0% +is this matrix a plus a do well if X is +in the null space of a it just kills it + + align:start position:0% +in the null space of a it just kills it + + + align:start position:0% +in the null space of a it just kills it +we just get 0 if X is not in the null + + align:start position:0% +we just get 0 if X is not in the null + + + align:start position:0% +we just get 0 if X is not in the null +space of a then we just get X back so + + align:start position:0% +space of a then we just get X back so + + + align:start position:0% +space of a then we just get X back so +it's essentially the identity matrix + + align:start position:0% +it's essentially the identity matrix + + + align:start position:0% +it's essentially the identity matrix +acting on X whenever X is in the column + + align:start position:0% +acting on X whenever X is in the column + + + align:start position:0% +acting on X whenever X is in the column +space of a transpose now specifically if + + align:start position:0% +space of a transpose now specifically if + + + align:start position:0% +space of a transpose now specifically if +a is invertible then a doesn't have a + + align:start position:0% +a is invertible then a doesn't have a + + + align:start position:0% +a is invertible then a doesn't have a +null space so what that means is when a + + align:start position:0% +null space so what that means is when a + + + align:start position:0% +null space so what that means is when a +is invertible a plus a recovers the + + align:start position:0% +is invertible a plus a recovers the + + + align:start position:0% +is invertible a plus a recovers the +identity because when we multiply it on + + align:start position:0% +identity because when we multiply it on + + + align:start position:0% +identity because when we multiply it on +any vector we get that vector back ok so + + align:start position:0% +any vector we get that vector back ok so + + + align:start position:0% +any vector we get that vector back ok so +I'd like to conclude here and I'll see + + align:start position:0% +I'd like to conclude here and I'll see + + + align:start position:0% +I'd like to conclude here and I'll see +you next time \ No newline at end of file diff --git a/iTgy87R9yRE.txt b/iTgy87R9yRE.txt new file mode 100644 index 0000000000000000000000000000000000000000..c9aa02f08540122f537f2d7bc5fe0dd002e785d4 --- /dev/null +++ b/iTgy87R9yRE.txt @@ -0,0 +1,8896 @@ +align:start position:0% + +okay what is a bet cell + + align:start position:0% +okay what is a bet cell + + + align:start position:0% +okay what is a bet cell +and where is it + + align:start position:0% + + + + align:start position:0% + +a few of you were asking questions about + + align:start position:0% +a few of you were asking questions about + + + align:start position:0% +a few of you were asking questions about +that at the end of the last lecture + + align:start position:0% +that at the end of the last lecture + + + align:start position:0% +that at the end of the last lecture +so i thought i would start with that + + align:start position:0% +so i thought i would start with that + + + align:start position:0% +so i thought i would start with that +today + + align:start position:0% + + + + align:start position:0% + +what kind of a cell is it + + align:start position:0% +what kind of a cell is it + + + align:start position:0% +what kind of a cell is it +that kind of question in neuroscience + + align:start position:0% +that kind of question in neuroscience + + + align:start position:0% +that kind of question in neuroscience +has several different types of answers + + align:start position:0% +has several different types of answers + + + align:start position:0% +has several different types of answers +first of all it's a neuron + + align:start position:0% + + + + align:start position:0% + +the main cell that communicates in the + + align:start position:0% +the main cell that communicates in the + + + align:start position:0% +the main cell that communicates in the +central nervous system or in the + + align:start position:0% +central nervous system or in the + + + align:start position:0% +central nervous system or in the +peripheral nervous system + + align:start position:0% + + + + align:start position:0% + +but + + align:start position:0% +but + + + align:start position:0% +but +another answer would be it's a + + align:start position:0% +another answer would be it's a + + + align:start position:0% +another answer would be it's a +certain type of neuron it's a pyramidal + + align:start position:0% +certain type of neuron it's a pyramidal + + + align:start position:0% +certain type of neuron it's a pyramidal +cell + + align:start position:0% +cell + + + align:start position:0% +cell +in the neocortex + + align:start position:0% + + + + align:start position:0% + +that cells are in the + + align:start position:0% +that cells are in the + + + align:start position:0% +that cells are in the +the major output layer + + align:start position:0% +the major output layer + + + align:start position:0% +the major output layer +that is output + + align:start position:0% +that is output + + + align:start position:0% +that is output +to non-cortical sources so + + align:start position:0% +to non-cortical sources so + + + align:start position:0% +to non-cortical sources so +now you don't i don't know how much you + + align:start position:0% +now you don't i don't know how much you + + + align:start position:0% +now you don't i don't know how much you +know even what neocortex is and what + + align:start position:0% +know even what neocortex is and what + + + align:start position:0% +know even what neocortex is and what +subcortical sources means + + align:start position:0% +subcortical sources means + + + align:start position:0% +subcortical sources means +but you will be learning + + align:start position:0% +but you will be learning + + + align:start position:0% +but you will be learning +okay + + align:start position:0% +okay + + + align:start position:0% +okay +don't worry about it if you don't + + align:start position:0% +don't worry about it if you don't + + + align:start position:0% +don't worry about it if you don't +understand something when i first + + align:start position:0% +understand something when i first + + + align:start position:0% +understand something when i first +mention it + + align:start position:0% +mention it + + + align:start position:0% +mention it +anything i expect especially in anything + + align:start position:0% +anything i expect especially in anything + + + align:start position:0% +anything i expect especially in anything +or anatomical that i expect you to know + + align:start position:0% +or anatomical that i expect you to know + + + align:start position:0% +or anatomical that i expect you to know +i will repeat + + align:start position:0% +i will repeat + + + align:start position:0% +i will repeat +and add + + align:start position:0% +and add + + + align:start position:0% +and add +to the information a number of times + + align:start position:0% +to the information a number of times + + + align:start position:0% +to the information a number of times +okay + + align:start position:0% +okay + + + align:start position:0% +okay +it won't be something i just mentioned + + align:start position:0% +it won't be something i just mentioned + + + align:start position:0% +it won't be something i just mentioned +once + + align:start position:0% + + + + align:start position:0% + +so be patient with yourself + + align:start position:0% +so be patient with yourself + + + align:start position:0% +so be patient with yourself +i'm going to do something else this year + + align:start position:0% +i'm going to do something else this year + + + align:start position:0% +i'm going to do something else this year +that's different from what i've done in + + align:start position:0% +that's different from what i've done in + + + align:start position:0% +that's different from what i've done in +the past i realized that + + align:start position:0% +the past i realized that + + + align:start position:0% +the past i realized that +these two classes that i teach + + align:start position:0% +these two classes that i teach + + + align:start position:0% +these two classes that i teach +undergraduates + + align:start position:0% +undergraduates + + + align:start position:0% +undergraduates +require you to + + align:start position:0% +require you to + + + align:start position:0% +require you to +basically acquire a language you learn + + align:start position:0% +basically acquire a language you learn + + + align:start position:0% +basically acquire a language you learn +many many new terms + + align:start position:0% +many many new terms + + + align:start position:0% +many many new terms +so we're going to make available to all + + align:start position:0% +so we're going to make available to all + + + align:start position:0% +so we're going to make available to all +of you a program basically a flash card + + align:start position:0% +of you a program basically a flash card + + + align:start position:0% +of you a program basically a flash card +program but it's probably the best of + + align:start position:0% +program but it's probably the best of + + + align:start position:0% +program but it's probably the best of +its type written here at mit + + align:start position:0% +its type written here at mit + + + align:start position:0% +its type written here at mit +by a student of mine in course 6 + + align:start position:0% +by a student of mine in course 6 + + + align:start position:0% +by a student of mine in course 6 +jordan gilliland he will come to the + + align:start position:0% +jordan gilliland he will come to the + + + align:start position:0% +jordan gilliland he will come to the +class probably + + align:start position:0% +class probably + + + align:start position:0% +class probably +next time + + align:start position:0% +next time + + + align:start position:0% +next time +either next time or friday + + align:start position:0% +either next time or friday + + + align:start position:0% +either next time or friday +and describe the program he can + + align:start position:0% +and describe the program he can + + + align:start position:0% +and describe the program he can +demonstrate it to you on my computer + + align:start position:0% +demonstrate it to you on my computer + + + align:start position:0% +demonstrate it to you on my computer +and + + align:start position:0% +and + + + align:start position:0% +and +you can download it + + align:start position:0% +you can download it + + + align:start position:0% +you can download it +what i will do + + align:start position:0% +what i will do + + + align:start position:0% +what i will do +i will try to remember to do this today + + align:start position:0% +i will try to remember to do this today + + + align:start position:0% +i will try to remember to do this today +is i will + + align:start position:0% +is i will + + + align:start position:0% +is i will +put on the web + + align:start position:0% +put on the web + + + align:start position:0% +put on the web +some text files for the first lectures + + align:start position:0% +some text files for the first lectures + + + align:start position:0% +some text files for the first lectures +that will give you terms and definitions + + align:start position:0% +that will give you terms and definitions + + + align:start position:0% +that will give you terms and definitions +that will help you in your study but + + align:start position:0% +that will help you in your study but + + + align:start position:0% +that will help you in your study but +those will be the files that are used in + + align:start position:0% +those will be the files that are used in + + + align:start position:0% +those will be the files that are used in +his program very useful for learning + + align:start position:0% + + + + align:start position:0% + +definitions learning languages it's used + + align:start position:0% +definitions learning languages it's used + + + align:start position:0% +definitions learning languages it's used +in the mandarin and japanese classes + + align:start position:0% +in the mandarin and japanese classes + + + align:start position:0% +in the mandarin and japanese classes +here + + align:start position:0% + + + + align:start position:0% + +i said a bet cell is a + + align:start position:0% +i said a bet cell is a + + + align:start position:0% +i said a bet cell is a +cell in the neocortex in the layer that + + align:start position:0% +cell in the neocortex in the layer that + + + align:start position:0% +cell in the neocortex in the layer that +provides output to non-cortical + + align:start position:0% +provides output to non-cortical + + + align:start position:0% +provides output to non-cortical +structures that means it must have a + + align:start position:0% +structures that means it must have a + + + align:start position:0% +structures that means it must have a +very long process + + align:start position:0% +very long process + + + align:start position:0% +very long process +okay + + align:start position:0% +okay + + + align:start position:0% +okay +right there it says a and this is a + + align:start position:0% +right there it says a and this is a + + + align:start position:0% +right there it says a and this is a +picture from monica hall + + align:start position:0% +picture from monica hall + + + align:start position:0% +picture from monica hall +that's the axon + + align:start position:0% +that's the axon + + + align:start position:0% +that's the axon +it shows two branches the accent starts + + align:start position:0% +it shows two branches the accent starts + + + align:start position:0% +it shows two branches the accent starts +here + + align:start position:0% +here + + + align:start position:0% +here +and then he has it going like that + + align:start position:0% +and then he has it going like that + + + align:start position:0% +and then he has it going like that +and then like that + + align:start position:0% +and then like that + + + align:start position:0% +and then like that +that's because on the section he was + + align:start position:0% +that's because on the section he was + + + align:start position:0% +that's because on the section he was +studying it was cut off + + align:start position:0% +studying it was cut off + + + align:start position:0% +studying it was cut off +now one of those branches would probably + + align:start position:0% +now one of those branches would probably + + + align:start position:0% +now one of those branches would probably +go up into the cortex and terminate on + + align:start position:0% +go up into the cortex and terminate on + + + align:start position:0% +go up into the cortex and terminate on +adjacent cells the other would go + + align:start position:0% +adjacent cells the other would go + + + align:start position:0% +adjacent cells the other would go +out + + align:start position:0% +out + + + align:start position:0% +out +leave the neocortex and the bet cells + + align:start position:0% +leave the neocortex and the bet cells + + + align:start position:0% +leave the neocortex and the bet cells +are large because they support a very + + align:start position:0% +are large because they support a very + + + align:start position:0% +are large because they support a very +long axon it goes all the way down to + + align:start position:0% +long axon it goes all the way down to + + + align:start position:0% +long axon it goes all the way down to +the spinal cord the longest ones would + + align:start position:0% +the spinal cord the longest ones would + + + align:start position:0% +the spinal cord the longest ones would +end at the bottom the spinal cord or + + align:start position:0% +end at the bottom the spinal cord or + + + align:start position:0% +end at the bottom the spinal cord or +near the bottom of the spinal cord like + + align:start position:0% +near the bottom of the spinal cord like + + + align:start position:0% +near the bottom of the spinal cord like +what we call the caudal enlargement that + + align:start position:0% +what we call the caudal enlargement that + + + align:start position:0% +what we call the caudal enlargement that +innervates the legs and feet + + align:start position:0% +innervates the legs and feet + + + align:start position:0% +innervates the legs and feet +okay + + align:start position:0% + + + + align:start position:0% + +okay we discussed + + align:start position:0% +okay we discussed + + + align:start position:0% +okay we discussed +car wernicke last time + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +in discussing localizational function we + + align:start position:0% +in discussing localizational function we + + + align:start position:0% +in discussing localizational function we +mentioned the kleist localization map + + align:start position:0% + + + + align:start position:0% + +and if you look + + align:start position:0% +and if you look + + + align:start position:0% +and if you look +i don't know if you can read it there + + align:start position:0% +i don't know if you can read it there + + + align:start position:0% +i don't know if you can read it there +but + + align:start position:0% +but + + + align:start position:0% +but +on your printout but these are basically + + align:start position:0% +on your printout but these are basically + + + align:start position:0% +on your printout but these are basically +psychological functions + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +that raised many questions and led to uh + + align:start position:0% +that raised many questions and led to uh + + + align:start position:0% +that raised many questions and led to uh +criticism and pointing out of many + + align:start position:0% +criticism and pointing out of many + + + align:start position:0% +criticism and pointing out of many +contradictions in the neurological + + align:start position:0% +contradictions in the neurological + + + align:start position:0% +contradictions in the neurological +literature so people + + align:start position:0% +literature so people + + + align:start position:0% +literature so people +started to simplify these maps the + + align:start position:0% +started to simplify these maps the + + + align:start position:0% +started to simplify these maps the +morgan and stellar map and the first + + align:start position:0% +morgan and stellar map and the first + + + align:start position:0% +morgan and stellar map and the first +text of physiological psychology took + + align:start position:0% +text of physiological psychology took + + + align:start position:0% +text of physiological psychology took +that to an extreme and only mentioned a + + align:start position:0% +that to an extreme and only mentioned a + + + align:start position:0% +that to an extreme and only mentioned a +few places like motor cortex visual + + align:start position:0% +few places like motor cortex visual + + + align:start position:0% +few places like motor cortex visual +visual cortex + + align:start position:0% + + + + align:start position:0% + +so what about this localization of + + align:start position:0% +so what about this localization of + + + align:start position:0% +so what about this localization of +function + + align:start position:0% +function + + + align:start position:0% +function +there's been argument about it since + + align:start position:0% +there's been argument about it since + + + align:start position:0% +there's been argument about it since +very early on + + align:start position:0% + + + + align:start position:0% + +now this should go back to your printout + + align:start position:0% + + + + align:start position:0% + +i hope you have those we have a few more + + align:start position:0% +i hope you have those we have a few more + + + align:start position:0% +i hope you have those we have a few more +today if you don't + + align:start position:0% + + + + align:start position:0% + +but the early objections were of the + + align:start position:0% +but the early objections were of the + + + align:start position:0% +but the early objections were of the +sort that you see + + align:start position:0% +sort that you see + + + align:start position:0% +sort that you see +at the top there + + align:start position:0% +at the top there + + + align:start position:0% +at the top there +isn't the human soul unitary how can you + + align:start position:0% +isn't the human soul unitary how can you + + + align:start position:0% +isn't the human soul unitary how can you +carve it up like that how can you say + + align:start position:0% +carve it up like that how can you say + + + align:start position:0% +carve it up like that how can you say +that one thing's here another thing's + + align:start position:0% +that one thing's here another thing's + + + align:start position:0% +that one thing's here another thing's +there + + align:start position:0% +there + + + align:start position:0% +there +is if people were a bunch of little + + align:start position:0% +is if people were a bunch of little + + + align:start position:0% +is if people were a bunch of little +people in the head + + align:start position:0% + + + + align:start position:0% + +a lot of it was because they would mix + + align:start position:0% +a lot of it was because they would mix + + + align:start position:0% +a lot of it was because they would mix +up arguments about mind + + align:start position:0% +up arguments about mind + + + align:start position:0% +up arguments about mind +and soul + + align:start position:0% + + + + align:start position:0% + +because many people assume they're the + + align:start position:0% +because many people assume they're the + + + align:start position:0% +because many people assume they're the +same + + align:start position:0% +same + + + align:start position:0% +same +and to a psychologist + + align:start position:0% +and to a psychologist + + + align:start position:0% +and to a psychologist +the mind is the organizer of behavior + + align:start position:0% +the mind is the organizer of behavior + + + align:start position:0% +the mind is the organizer of behavior +neuroscientist says behavior is + + align:start position:0% +neuroscientist says behavior is + + + align:start position:0% +neuroscientist says behavior is +organized by the brain that would mean + + align:start position:0% +organized by the brain that would mean + + + align:start position:0% +organized by the brain that would mean +the soul is the mind + + align:start position:0% +the soul is the mind + + + align:start position:0% +the soul is the mind +but in fact you don't have to assume + + align:start position:0% +but in fact you don't have to assume + + + align:start position:0% +but in fact you don't have to assume +that and it gets you into lots of + + align:start position:0% +that and it gets you into lots of + + + align:start position:0% +that and it gets you into lots of +problems if you do + + align:start position:0% + + + + align:start position:0% + +but let's talk about + + align:start position:0% +but let's talk about + + + align:start position:0% +but let's talk about +then another tradition that arose very + + align:start position:0% +then another tradition that arose very + + + align:start position:0% +then another tradition that arose very +early is sometimes referred to as + + align:start position:0% +early is sometimes referred to as + + + align:start position:0% +early is sometimes referred to as +anti-localization tradition + + align:start position:0% +anti-localization tradition + + + align:start position:0% +anti-localization tradition +but in fact they did believe in a kind + + align:start position:0% +but in fact they did believe in a kind + + + align:start position:0% +but in fact they did believe in a kind +of general + + align:start position:0% +of general + + + align:start position:0% +of general +localization of function + + align:start position:0% +localization of function + + + align:start position:0% +localization of function +and we can begin that with + + align:start position:0% +and we can begin that with + + + align:start position:0% +and we can begin that with +pierre florell + + align:start position:0% +pierre florell + + + align:start position:0% +pierre florell +who studied pigeons and other animals + + align:start position:0% +who studied pigeons and other animals + + + align:start position:0% +who studied pigeons and other animals +too + + align:start position:0% +too + + + align:start position:0% +too +published first in 1824 + + align:start position:0% +published first in 1824 + + + align:start position:0% +published first in 1824 +okay so this was at the time when + + align:start position:0% +okay so this was at the time when + + + align:start position:0% +okay so this was at the time when +uh + + align:start position:0% + + + + align:start position:0% + +phrenology was becoming popular + + align:start position:0% +phrenology was becoming popular + + + align:start position:0% +phrenology was becoming popular +uh + + align:start position:0% +uh + + + align:start position:0% +uh +it was before + + align:start position:0% + + + + align:start position:0% + +and the minute continued with other + + align:start position:0% +and the minute continued with other + + + align:start position:0% +and the minute continued with other +people + + align:start position:0% +people + + + align:start position:0% +people +after brocco + + align:start position:0% +after brocco + + + align:start position:0% +after brocco +let's talk a little bit about + + align:start position:0% +let's talk a little bit about + + + align:start position:0% +let's talk a little bit about +floral + + align:start position:0% +floral + + + align:start position:0% +floral +i've sketched here + + align:start position:0% +i've sketched here + + + align:start position:0% +i've sketched here +a picture of a pigeon brain + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% + + + + align:start position:0% + +when floral studied this brain he + + align:start position:0% +when floral studied this brain he + + + align:start position:0% +when floral studied this brain he +he did it by making lesions and he would + + align:start position:0% +he did it by making lesions and he would + + + align:start position:0% +he did it by making lesions and he would +make lesions in + + align:start position:0% +make lesions in + + + align:start position:0% +make lesions in +one of these four regions + + align:start position:0% + + + + align:start position:0% + +the lowest will start with the hindbrain + + align:start position:0% +the lowest will start with the hindbrain + + + align:start position:0% +the lowest will start with the hindbrain +cerebellum + + align:start position:0% +cerebellum + + + align:start position:0% +cerebellum +optic lobe + + align:start position:0% +optic lobe + + + align:start position:0% +optic lobe +and the cerebral hemispheres + + align:start position:0% +and the cerebral hemispheres + + + align:start position:0% +and the cerebral hemispheres +okay + + align:start position:0% + + + + align:start position:0% + +so let's say he made a lesion in the + + align:start position:0% +so let's say he made a lesion in the + + + align:start position:0% +so let's say he made a lesion in the +hind brain + + align:start position:0% +hind brain + + + align:start position:0% +hind brain +he found that if he made a big enough + + align:start position:0% +he found that if he made a big enough + + + align:start position:0% +he found that if he made a big enough +lesion in the hind brain the animal just + + align:start position:0% +lesion in the hind brain the animal just + + + align:start position:0% +lesion in the hind brain the animal just +died + + align:start position:0% +died + + + align:start position:0% +died +he was disturbing + + align:start position:0% +he was disturbing + + + align:start position:0% +he was disturbing +vital functions + + align:start position:0% +vital functions + + + align:start position:0% +vital functions +we know that to be true now + + align:start position:0% +we know that to be true now + + + align:start position:0% +we know that to be true now +but he claimed that in fact the amount + + align:start position:0% +but he claimed that in fact the amount + + + align:start position:0% +but he claimed that in fact the amount +of disturbance depended on the size of + + align:start position:0% +of disturbance depended on the size of + + + align:start position:0% +of disturbance depended on the size of +the lesion but it didn't really seem to + + align:start position:0% +the lesion but it didn't really seem to + + + align:start position:0% +the lesion but it didn't really seem to +make it + + align:start position:0% +make it + + + align:start position:0% +make it +matter where in the hind brain he made + + align:start position:0% +matter where in the hind brain he made + + + align:start position:0% +matter where in the hind brain he made +the lesion + + align:start position:0% +the lesion + + + align:start position:0% +the lesion +so he claimed there wasn't any very + + align:start position:0% +so he claimed there wasn't any very + + + align:start position:0% +so he claimed there wasn't any very +specific localization but there was + + align:start position:0% +specific localization but there was + + + align:start position:0% +specific localization but there was +vital functions were localized in the + + align:start position:0% +vital functions were localized in the + + + align:start position:0% +vital functions were localized in the +hindbrain because when he made lesions + + align:start position:0% +hindbrain because when he made lesions + + + align:start position:0% +hindbrain because when he made lesions +in these other areas the animal didn't + + align:start position:0% +in these other areas the animal didn't + + + align:start position:0% +in these other areas the animal didn't +he didn't deserve vital functions the + + align:start position:0% +he didn't deserve vital functions the + + + align:start position:0% +he didn't deserve vital functions the +animal usually lived + + align:start position:0% + + + + align:start position:0% + +at least for a while + + align:start position:0% + + + + align:start position:0% + +okay if he made lesions + + align:start position:0% +okay if he made lesions + + + align:start position:0% +okay if he made lesions +in the second area here + + align:start position:0% +in the second area here + + + align:start position:0% +in the second area here +i've abbreviated cb + + align:start position:0% +i've abbreviated cb + + + align:start position:0% +i've abbreviated cb +that means + + align:start position:0% + + + + align:start position:0% + +cerebellum + + align:start position:0% + + + + align:start position:0% + +a structure present in mammals as well + + align:start position:0% +a structure present in mammals as well + + + align:start position:0% +a structure present in mammals as well +all the vertebrates + + align:start position:0% +all the vertebrates + + + align:start position:0% +all the vertebrates +i claimed if he made a lesion there + + align:start position:0% +i claimed if he made a lesion there + + + align:start position:0% +i claimed if he made a lesion there +again the disturbance depended on + + align:start position:0% +again the disturbance depended on + + + align:start position:0% +again the disturbance depended on +the size of the lesion and not exact not + + align:start position:0% +the size of the lesion and not exact not + + + align:start position:0% +the size of the lesion and not exact not +the exact location + + align:start position:0% +the exact location + + + align:start position:0% +the exact location +he said it disturbed motor coordination + + align:start position:0% +he said it disturbed motor coordination + + + align:start position:0% +he said it disturbed motor coordination +so if he was doing it in his pigeons + + align:start position:0% +so if he was doing it in his pigeons + + + align:start position:0% +so if he was doing it in his pigeons +they became more and more clumsy + + align:start position:0% +they became more and more clumsy + + + align:start position:0% +they became more and more clumsy +depending on how big a lesion he made in + + align:start position:0% +depending on how big a lesion he made in + + + align:start position:0% +depending on how big a lesion he made in +the cerebellum + + align:start position:0% + + + + align:start position:0% + +if he made a lesion in region 3 there + + align:start position:0% +if he made a lesion in region 3 there + + + align:start position:0% +if he made a lesion in region 3 there +the optic lobe was called the optic + + align:start position:0% +the optic lobe was called the optic + + + align:start position:0% +the optic lobe was called the optic +globe because + + align:start position:0% +globe because + + + align:start position:0% +globe because +even with + + align:start position:0% +even with + + + align:start position:0% +even with +just gross anatomical dissection without + + align:start position:0% +just gross anatomical dissection without + + + align:start position:0% +just gross anatomical dissection without +doing any + + align:start position:0% +doing any + + + align:start position:0% +doing any +sectioning of the brain + + align:start position:0% +sectioning of the brain + + + align:start position:0% +sectioning of the brain +you could see that it was connected to + + align:start position:0% +you could see that it was connected to + + + align:start position:0% +you could see that it was connected to +the eyes + + align:start position:0% +the eyes + + + align:start position:0% +the eyes +okay through the optic nerve and tract + + align:start position:0% + + + + align:start position:0% + +and he surprisingly actually considering + + align:start position:0% +and he surprisingly actually considering + + + align:start position:0% +and he surprisingly actually considering +what we know about it today he claimed + + align:start position:0% +what we know about it today he claimed + + + align:start position:0% +what we know about it today he claimed +that vision was disturbed but it didn't + + align:start position:0% +that vision was disturbed but it didn't + + + align:start position:0% +that vision was disturbed but it didn't +make a difference where he put the + + align:start position:0% +make a difference where he put the + + + align:start position:0% +make a difference where he put the +lesion + + align:start position:0% +lesion + + + align:start position:0% +lesion +but if he made a big lesion and disturb + + align:start position:0% +but if he made a big lesion and disturb + + + align:start position:0% +but if he made a big lesion and disturb +vision a lot + + align:start position:0% + + + + align:start position:0% + +i say it's surprising because we know + + align:start position:0% +i say it's surprising because we know + + + align:start position:0% +i say it's surprising because we know +that the left eye is connected to the + + align:start position:0% +that the left eye is connected to the + + + align:start position:0% +that the left eye is connected to the +right optic lobe in the pigeon right eye + + align:start position:0% +right optic lobe in the pigeon right eye + + + align:start position:0% +right optic lobe in the pigeon right eye +to the left optic lobe so you should + + align:start position:0% +to the left optic lobe so you should + + + align:start position:0% +to the left optic lobe so you should +have been able to tell the difference + + align:start position:0% +have been able to tell the difference + + + align:start position:0% +have been able to tell the difference +between visual fields + + align:start position:0% + + + + align:start position:0% + +finally if he made lesions in the + + align:start position:0% +finally if he made lesions in the + + + align:start position:0% +finally if he made lesions in the +cerebral hemisphere he claimed disturbed + + align:start position:0% +cerebral hemisphere he claimed disturbed + + + align:start position:0% +cerebral hemisphere he claimed disturbed +functions like + + align:start position:0% +functions like + + + align:start position:0% +functions like +ability to initiate action he didn't use + + align:start position:0% +ability to initiate action he didn't use + + + align:start position:0% +ability to initiate action he didn't use +those terms he called it volition and + + align:start position:0% +those terms he called it volition and + + + align:start position:0% +those terms he called it volition and +will + + align:start position:0% + + + + align:start position:0% + +and again it just depended on how big + + align:start position:0% +and again it just depended on how big + + + align:start position:0% +and again it just depended on how big +the lesion + + align:start position:0% +the lesion + + + align:start position:0% +the lesion +so in other words he + + align:start position:0% +so in other words he + + + align:start position:0% +so in other words he +didn't agree with the localization of + + align:start position:0% +didn't agree with the localization of + + + align:start position:0% +didn't agree with the localization of +function people but remember he was + + align:start position:0% +function people but remember he was + + + align:start position:0% +function people but remember he was +using these small animals + + align:start position:0% +using these small animals + + + align:start position:0% +using these small animals +he wasn't using + + align:start position:0% +he wasn't using + + + align:start position:0% +he wasn't using +animals + + align:start position:0% +animals + + + align:start position:0% +animals +very close to + + align:start position:0% +very close to + + + align:start position:0% +very close to +the human brain + + align:start position:0% + + + + align:start position:0% + +but + + align:start position:0% +but + + + align:start position:0% +but +other scientists later on + + align:start position:0% +other scientists later on + + + align:start position:0% +other scientists later on +continued that with that same kind of + + align:start position:0% +continued that with that same kind of + + + align:start position:0% +continued that with that same kind of +argument + + align:start position:0% +argument + + + align:start position:0% +argument +golds and published in 1876 studies of + + align:start position:0% +golds and published in 1876 studies of + + + align:start position:0% +golds and published in 1876 studies of +dogs now dogs are a mammal they have a + + align:start position:0% +dogs now dogs are a mammal they have a + + + align:start position:0% +dogs now dogs are a mammal they have a +very a pretty large brain + + align:start position:0% +very a pretty large brain + + + align:start position:0% +very a pretty large brain +much closer to our brains + + align:start position:0% +much closer to our brains + + + align:start position:0% +much closer to our brains +and yet he came to conclusions pretty + + align:start position:0% +and yet he came to conclusions pretty + + + align:start position:0% +and yet he came to conclusions pretty +similar to fluron he studied mainly the + + align:start position:0% +similar to fluron he studied mainly the + + + align:start position:0% +similar to fluron he studied mainly the +cerebral hemispheres he was making + + align:start position:0% +cerebral hemispheres he was making + + + align:start position:0% +cerebral hemispheres he was making +lesions in the neocortex + + align:start position:0% +lesions in the neocortex + + + align:start position:0% +lesions in the neocortex +and he claimed he was disturbing higher + + align:start position:0% +and he claimed he was disturbing higher + + + align:start position:0% +and he claimed he was disturbing higher +higher functions just like + + align:start position:0% +higher functions just like + + + align:start position:0% +higher functions just like +the sort of functions that floral had + + align:start position:0% +the sort of functions that floral had + + + align:start position:0% +the sort of functions that floral had +claimed for his small animals + + align:start position:0% + + + + align:start position:0% + +but he the problem was + + align:start position:0% +but he the problem was + + + align:start position:0% +but he the problem was +as i see it with gold is he he was using + + align:start position:0% +as i see it with gold is he he was using + + + align:start position:0% +as i see it with gold is he he was using +very general terms to describe behavior + + align:start position:0% +very general terms to describe behavior + + + align:start position:0% +very general terms to describe behavior +he didn't have any he didn't do + + align:start position:0% +he didn't have any he didn't do + + + align:start position:0% +he didn't have any he didn't do +experiments + + align:start position:0% +experiments + + + align:start position:0% +experiments +he didn't analyze behavior in any very + + align:start position:0% +he didn't analyze behavior in any very + + + align:start position:0% +he didn't analyze behavior in any very +specific way this was before + + align:start position:0% +specific way this was before + + + align:start position:0% +specific way this was before +the development of ethology the study of + + align:start position:0% +the development of ethology the study of + + + align:start position:0% +the development of ethology the study of +natural behaviors and animals + + align:start position:0% +natural behaviors and animals + + + align:start position:0% +natural behaviors and animals +it was before the development + + align:start position:0% +it was before the development + + + align:start position:0% +it was before the development +of + + align:start position:0% +of + + + align:start position:0% +of +experimental psychology + + align:start position:0% + + + + align:start position:0% + +so his problem was really a lack of + + align:start position:0% +so his problem was really a lack of + + + align:start position:0% +so his problem was really a lack of +analysis + + align:start position:0% + + + + align:start position:0% + +he wasn't look it just depends on how he + + align:start position:0% +he wasn't look it just depends on how he + + + align:start position:0% +he wasn't look it just depends on how he +was looking at the animals + + align:start position:0% + + + + align:start position:0% + +higher functions he claimed things like + + align:start position:0% +higher functions he claimed things like + + + align:start position:0% +higher functions he claimed things like +volition + + align:start position:0% +volition + + + align:start position:0% +volition +will initiation + + align:start position:0% +will initiation + + + align:start position:0% +will initiation +of action + + align:start position:0% +of action + + + align:start position:0% +of action +[Music] + + align:start position:0% + + + + align:start position:0% + +now there were other people around that + + align:start position:0% +now there were other people around that + + + align:start position:0% +now there were other people around that +same time that were discovering + + align:start position:0% +same time that were discovering + + + align:start position:0% +same time that were discovering +greater localization + + align:start position:0% +greater localization + + + align:start position:0% +greater localization +it was around that time that people + + align:start position:0% +it was around that time that people + + + align:start position:0% +it was around that time that people +began to see that vision was disturbed + + align:start position:0% +began to see that vision was disturbed + + + align:start position:0% +began to see that vision was disturbed +with more posterior lesions in the + + align:start position:0% +with more posterior lesions in the + + + align:start position:0% +with more posterior lesions in the +hemispheres okay + + align:start position:0% +hemispheres okay + + + align:start position:0% +hemispheres okay +and lashley was one of those people + + align:start position:0% +and lashley was one of those people + + + align:start position:0% +and lashley was one of those people +later on who did localize the visual + + align:start position:0% +later on who did localize the visual + + + align:start position:0% +later on who did localize the visual +cortex but in his early work + + align:start position:0% +cortex but in his early work + + + align:start position:0% +cortex but in his early work +he did a large lesion study trying to + + align:start position:0% +he did a large lesion study trying to + + + align:start position:0% +he did a large lesion study trying to +locate the engram + + align:start position:0% + + + + align:start position:0% + +okay so let's talk about lashley studies + + align:start position:0% +okay so let's talk about lashley studies + + + align:start position:0% +okay so let's talk about lashley studies +lashley's an important figure in brain + + align:start position:0% +lashley's an important figure in brain + + + align:start position:0% +lashley's an important figure in brain +behavior studies because + + align:start position:0% +behavior studies because + + + align:start position:0% +behavior studies because +unlike the clinical neurologists + + align:start position:0% +unlike the clinical neurologists + + + align:start position:0% +unlike the clinical neurologists +he did experiments he wasn't just + + align:start position:0% +he did experiments he wasn't just + + + align:start position:0% +he did experiments he wasn't just +informally making informal descriptions + + align:start position:0% +informally making informal descriptions + + + align:start position:0% +informally making informal descriptions +of case single cases okay he was using + + align:start position:0% +of case single cases okay he was using + + + align:start position:0% +of case single cases okay he was using +quite a few animals in each experiment + + align:start position:0% +quite a few animals in each experiment + + + align:start position:0% +quite a few animals in each experiment +so he was basically repeating the + + align:start position:0% +so he was basically repeating the + + + align:start position:0% +so he was basically repeating the +experiment many times in different + + align:start position:0% +experiment many times in different + + + align:start position:0% +experiment many times in different +animals + + align:start position:0% +animals + + + align:start position:0% +animals +he was using quantitative methods + + align:start position:0% +he was using quantitative methods + + + align:start position:0% +he was using quantitative methods +applied to both behavior + + align:start position:0% +applied to both behavior + + + align:start position:0% +applied to both behavior +and anatomy + + align:start position:0% +and anatomy + + + align:start position:0% +and anatomy +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and he was the first one really to do + + align:start position:0% +and he was the first one really to do + + + align:start position:0% +and he was the first one really to do +that systematically + + align:start position:0% +that systematically + + + align:start position:0% +that systematically +and that's why we consider him important + + align:start position:0% +and that's why we consider him important + + + align:start position:0% +and that's why we consider him important +even though + + align:start position:0% +even though + + + align:start position:0% +even though +this particular study he was his + + align:start position:0% +this particular study he was his + + + align:start position:0% +this particular study he was his +conclusions were probably wrong so let's + + align:start position:0% +conclusions were probably wrong so let's + + + align:start position:0% +conclusions were probably wrong so let's +look at that + + align:start position:0% +look at that + + + align:start position:0% +look at that +first i'll show you this picture + + align:start position:0% +first i'll show you this picture + + + align:start position:0% +first i'll show you this picture +taken + + align:start position:0% +taken + + + align:start position:0% +taken +by myself showing hamster brains because + + align:start position:0% +by myself showing hamster brains because + + + align:start position:0% +by myself showing hamster brains because +they're pretty similar to rap + + align:start position:0% +they're pretty similar to rap + + + align:start position:0% +they're pretty similar to rap +i'm showing an adult in a newborn brain + + align:start position:0% +i'm showing an adult in a newborn brain + + + align:start position:0% +i'm showing an adult in a newborn brain +and you'll note there that in the adult + + align:start position:0% +and you'll note there that in the adult + + + align:start position:0% +and you'll note there that in the adult +brain + + align:start position:0% + + + + align:start position:0% + +then you appear + + align:start position:0% +then you appear + + + align:start position:0% +then you appear +neocortex okay + + align:start position:0% + + + + align:start position:0% + +you'll note that it's a smooth brain + + align:start position:0% +you'll note that it's a smooth brain + + + align:start position:0% +you'll note that it's a smooth brain +animal + + align:start position:0% +animal + + + align:start position:0% +animal +it doesn't seem to be divided up + + align:start position:0% + + + + align:start position:0% + +by the kinds of + + align:start position:0% +by the kinds of + + + align:start position:0% +by the kinds of +fissures that you see + + align:start position:0% +fissures that you see + + + align:start position:0% +fissures that you see +in + + align:start position:0% +in + + + align:start position:0% +in +larger brained animals + + align:start position:0% + + + + align:start position:0% + +but anatomical studies do indicate some + + align:start position:0% +but anatomical studies do indicate some + + + align:start position:0% +but anatomical studies do indicate some +subdivisions in that cortex + + align:start position:0% +subdivisions in that cortex + + + align:start position:0% +subdivisions in that cortex +you can also see their subcortical + + align:start position:0% +you can also see their subcortical + + + align:start position:0% +you can also see their subcortical +regions + + align:start position:0% +regions + + + align:start position:0% +regions +if you think of the neocortex it's the + + align:start position:0% +if you think of the neocortex it's the + + + align:start position:0% +if you think of the neocortex it's the +highest part of the brain + + align:start position:0% +highest part of the brain + + + align:start position:0% +highest part of the brain +all these other structures are below it + + align:start position:0% +all these other structures are below it + + + align:start position:0% +all these other structures are below it +in between the spinal cord which you see + + align:start position:0% +in between the spinal cord which you see + + + align:start position:0% +in between the spinal cord which you see +beginning right here + + align:start position:0% +beginning right here + + + align:start position:0% +beginning right here +and then here + + align:start position:0% +and then here + + + align:start position:0% +and then here +behind brain begins the hind brain is + + align:start position:0% +behind brain begins the hind brain is + + + align:start position:0% +behind brain begins the hind brain is +partly covered here by the cerebellum + + align:start position:0% +partly covered here by the cerebellum + + + align:start position:0% +partly covered here by the cerebellum +and then you also see a little bit of + + align:start position:0% +and then you also see a little bit of + + + align:start position:0% +and then you also see a little bit of +the + + align:start position:0% +the + + + align:start position:0% +the +superior colliculus which is the + + align:start position:0% +superior colliculus which is the + + + align:start position:0% +superior colliculus which is the +mammalian equivalent of the optic lobe + + align:start position:0% +mammalian equivalent of the optic lobe + + + align:start position:0% +mammalian equivalent of the optic lobe +in the pigeon + + align:start position:0% +in the pigeon + + + align:start position:0% +in the pigeon +okay + + align:start position:0% + + + + align:start position:0% + +well here's lashley's way of depicting + + align:start position:0% +well here's lashley's way of depicting + + + align:start position:0% +well here's lashley's way of depicting +his lesions + + align:start position:0% +his lesions + + + align:start position:0% +his lesions +here's + + align:start position:0% +here's + + + align:start position:0% +here's +here's was + + align:start position:0% +here's was + + + align:start position:0% +here's was +here here was his approach his idea was + + align:start position:0% +here here was his approach his idea was + + + align:start position:0% +here here was his approach his idea was +we will train the rats + + align:start position:0% +we will train the rats + + + align:start position:0% +we will train the rats +in problems we'll get them to solve + + align:start position:0% +in problems we'll get them to solve + + + align:start position:0% +in problems we'll get them to solve +mazes + + align:start position:0% +mazes + + + align:start position:0% +mazes +okay + + align:start position:0% +okay + + + align:start position:0% +okay +we'll teach throughout the maze and then + + align:start position:0% +we'll teach throughout the maze and then + + + align:start position:0% +we'll teach throughout the maze and then +we'll make a lesion + + align:start position:0% +we'll make a lesion + + + align:start position:0% +we'll make a lesion +to see if this memory for the maze that + + align:start position:0% +to see if this memory for the maze that + + + align:start position:0% +to see if this memory for the maze that +he's learned + + align:start position:0% +he's learned + + + align:start position:0% +he's learned +disappears okay so then we'll + + align:start position:0% +disappears okay so then we'll + + + align:start position:0% +disappears okay so then we'll +we'll train him in the maze and we'll + + align:start position:0% +we'll train him in the maze and we'll + + + align:start position:0% +we'll train him in the maze and we'll +make the lesion + + align:start position:0% +make the lesion + + + align:start position:0% +make the lesion +and now after he recovers from lesion + + align:start position:0% +and now after he recovers from lesion + + + align:start position:0% +and now after he recovers from lesion +we'll retrain him + + align:start position:0% +we'll retrain him + + + align:start position:0% +we'll retrain him +and find out now does he + + align:start position:0% +and find out now does he + + + align:start position:0% +and find out now does he +have to learn all over again + + align:start position:0% +have to learn all over again + + + align:start position:0% +have to learn all over again +or does he still remember + + align:start position:0% +or does he still remember + + + align:start position:0% +or does he still remember +and he made a great variety of lesions + + align:start position:0% +and he made a great variety of lesions + + + align:start position:0% +and he made a great variety of lesions +this is an example of his lesion + + align:start position:0% +this is an example of his lesion + + + align:start position:0% +this is an example of his lesion +reconstructions + + align:start position:0% +reconstructions + + + align:start position:0% +reconstructions +of a rat with a + + align:start position:0% +of a rat with a + + + align:start position:0% +of a rat with a +smaller lesion and a larger lesion + + align:start position:0% + + + + align:start position:0% + +he tried to make these lesions + + align:start position:0% +he tried to make these lesions + + + align:start position:0% +he tried to make these lesions +symmetrically + + align:start position:0% + + + + align:start position:0% + +and you can see + + align:start position:0% +and you can see + + + align:start position:0% +and you can see +the symmetry of the lesion is not + + align:start position:0% +the symmetry of the lesion is not + + + align:start position:0% +the symmetry of the lesion is not +perfect but it's not easy in + + align:start position:0% +perfect but it's not easy in + + + align:start position:0% +perfect but it's not easy in +neurosurgery to make completely + + align:start position:0% +neurosurgery to make completely + + + align:start position:0% +neurosurgery to make completely +symmetric lesions but he + + align:start position:0% +symmetric lesions but he + + + align:start position:0% +symmetric lesions but he +attempted to do that but then he didn't + + align:start position:0% +attempted to do that but then he didn't + + + align:start position:0% +attempted to do that but then he didn't +depend on his + + align:start position:0% +depend on his + + + align:start position:0% +depend on his +surgical notes + + align:start position:0% +surgical notes + + + align:start position:0% +surgical notes +he did histology on the brain afterwards + + align:start position:0% +he did histology on the brain afterwards + + + align:start position:0% +he did histology on the brain afterwards +and reconstructed the lesion + + align:start position:0% +and reconstructed the lesion + + + align:start position:0% +and reconstructed the lesion +that's very important because you can do + + align:start position:0% +that's very important because you can do + + + align:start position:0% +that's very important because you can do +extra damage you can damage blood + + align:start position:0% +extra damage you can damage blood + + + align:start position:0% +extra damage you can damage blood +vessels and produce damage you weren't + + align:start position:0% +vessels and produce damage you weren't + + + align:start position:0% +vessels and produce damage you weren't +intending + + align:start position:0% +intending + + + align:start position:0% +intending +or you might have missed some structures + + align:start position:0% +or you might have missed some structures + + + align:start position:0% +or you might have missed some structures +that you were intending to remove so + + align:start position:0% +that you were intending to remove so + + + align:start position:0% +that you were intending to remove so +it's very important to + + align:start position:0% +it's very important to + + + align:start position:0% +it's very important to +follow up any lesion study like this + + align:start position:0% +follow up any lesion study like this + + + align:start position:0% +follow up any lesion study like this +with + + align:start position:0% +with + + + align:start position:0% +with +at least this kind of anatomy + + align:start position:0% +at least this kind of anatomy + + + align:start position:0% +at least this kind of anatomy +reconstructing the + + align:start position:0% +reconstructing the + + + align:start position:0% +reconstructing the +tissue + + align:start position:0% +tissue + + + align:start position:0% +tissue +the only problem with it is sometimes + + align:start position:0% +the only problem with it is sometimes + + + align:start position:0% +the only problem with it is sometimes +the brains become a little distorted + + align:start position:0% +the brains become a little distorted + + + align:start position:0% +the brains become a little distorted +after a lesion and then you have + + align:start position:0% +after a lesion and then you have + + + align:start position:0% +after a lesion and then you have +difficulty + + align:start position:0% +difficulty + + + align:start position:0% +difficulty +putting + + align:start position:0% +putting + + + align:start position:0% +putting +the lesion in this kind of picture this + + align:start position:0% +the lesion in this kind of picture this + + + align:start position:0% +the lesion in this kind of picture this +is a standard diagram + + align:start position:0% +is a standard diagram + + + align:start position:0% +is a standard diagram +yes + + align:start position:0% + + + + align:start position:0% + +good question you know this is not + + align:start position:0% +good question you know this is not + + + align:start position:0% +good question you know this is not +showing the depth of the lesion + + align:start position:0% +showing the depth of the lesion + + + align:start position:0% +showing the depth of the lesion +he tried to make to remove only cell + + align:start position:0% +he tried to make to remove only cell + + + align:start position:0% +he tried to make to remove only cell +layers of the neocortex and avoid going + + align:start position:0% +layers of the neocortex and avoid going + + + align:start position:0% +layers of the neocortex and avoid going +deep + + align:start position:0% +deep + + + align:start position:0% +deep +but of course that's a question that + + align:start position:0% +but of course that's a question that + + + align:start position:0% +but of course that's a question that +this picture isn't showing you well + + align:start position:0% +this picture isn't showing you well + + + align:start position:0% +this picture isn't showing you well +where did he go deeper because if he + + align:start position:0% +where did he go deeper because if he + + + align:start position:0% +where did he go deeper because if he +went deeper he's going to disturb fibers + + align:start position:0% +went deeper he's going to disturb fibers + + + align:start position:0% +went deeper he's going to disturb fibers +he might even disturb underlying + + align:start position:0% +he might even disturb underlying + + + align:start position:0% +he might even disturb underlying +non-neocortical structures + + align:start position:0% +non-neocortical structures + + + align:start position:0% +non-neocortical structures +but for the most part his lesions were + + align:start position:0% +but for the most part his lesions were + + + align:start position:0% +but for the most part his lesions were +done pretty well + + align:start position:0% +done pretty well + + + align:start position:0% +done pretty well +using aspiration of the superficial + + align:start position:0% +using aspiration of the superficial + + + align:start position:0% +using aspiration of the superficial +cells in the cortex the upper + + align:start position:0% +cells in the cortex the upper + + + align:start position:0% +cells in the cortex the upper +what we call the + + align:start position:0% +what we call the + + + align:start position:0% +what we call the +bark of the brain the neocortex and + + align:start position:0% +bark of the brain the neocortex and + + + align:start position:0% +bark of the brain the neocortex and +avoiding the fibers underneath + + align:start position:0% + + + + align:start position:0% + +okay so here + + align:start position:0% +okay so here + + + align:start position:0% +okay so here +were the mazes he used he had three + + align:start position:0% +were the mazes he used he had three + + + align:start position:0% +were the mazes he used he had three +different mazes + + align:start position:0% +different mazes + + + align:start position:0% +different mazes +the one at the bottom there very simple + + align:start position:0% +the one at the bottom there very simple + + + align:start position:0% +the one at the bottom there very simple +maze + + align:start position:0% +maze + + + align:start position:0% +maze +it just requires the animal to turn left + + align:start position:0% +it just requires the animal to turn left + + + align:start position:0% +it just requires the animal to turn left +the animals put here + + align:start position:0% +the animals put here + + + align:start position:0% +the animals put here +which says s that's the start box + + align:start position:0% +which says s that's the start box + + + align:start position:0% +which says s that's the start box +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and the + + align:start position:0% +and the + + + align:start position:0% +and the +food is placed on one side and not the + + align:start position:0% +food is placed on one side and not the + + + align:start position:0% +food is placed on one side and not the +other the f indicates food + + align:start position:0% + + + + align:start position:0% + +and then + + align:start position:0% +and then + + + align:start position:0% +and then +he trains him for a number of trials + + align:start position:0% +he trains him for a number of trials + + + align:start position:0% +he trains him for a number of trials +until the rat now is always turning left + + align:start position:0% + + + + align:start position:0% + +maze 2 is a little more complex and mace + + align:start position:0% +maze 2 is a little more complex and mace + + + align:start position:0% +maze 2 is a little more complex and mace + + align:start position:0% + + + align:start position:0% +is the most complex + + align:start position:0% + + + + align:start position:0% + +so this method again is to train on one + + align:start position:0% +so this method again is to train on one + + + align:start position:0% +so this method again is to train on one +of the mazes only one of them + + align:start position:0% +of the mazes only one of them + + + align:start position:0% +of the mazes only one of them +then make the lesion bilateral lesion + + align:start position:0% +then make the lesion bilateral lesion + + + align:start position:0% +then make the lesion bilateral lesion +then he waited so + + align:start position:0% +then he waited so + + + align:start position:0% +then he waited so +the animal is no longer affected by the + + align:start position:0% +the animal is no longer affected by the + + + align:start position:0% +the animal is no longer affected by the +anesthetic and he recovers for a while + + align:start position:0% +anesthetic and he recovers for a while + + + align:start position:0% +anesthetic and he recovers for a while +from the lesion i don't remember how + + align:start position:0% +from the lesion i don't remember how + + + align:start position:0% +from the lesion i don't remember how +long he recovered + + align:start position:0% +long he recovered + + + align:start position:0% +long he recovered +he let the animals recover probably at + + align:start position:0% +he let the animals recover probably at + + + align:start position:0% +he let the animals recover probably at +least two weeks + + align:start position:0% +least two weeks + + + align:start position:0% +least two weeks +and then he tested for retention + + align:start position:0% +and then he tested for retention + + + align:start position:0% +and then he tested for retention +the question was is the memory still + + align:start position:0% +the question was is the memory still + + + align:start position:0% +the question was is the memory still +there + + align:start position:0% +there + + + align:start position:0% +there +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now this is + + align:start position:0% +now this is + + + align:start position:0% +now this is +a diagram of his findings + + align:start position:0% + + + + align:start position:0% + +basically + + align:start position:0% + + + + align:start position:0% + +well on the abscissa very showing the + + align:start position:0% +well on the abscissa very showing the + + + align:start position:0% +well on the abscissa very showing the +percentage destruction of the neocortex + + align:start position:0% +percentage destruction of the neocortex + + + align:start position:0% +percentage destruction of the neocortex +now notice there's nothing about + + align:start position:0% +now notice there's nothing about + + + align:start position:0% +now notice there's nothing about +localization there just percentage of + + align:start position:0% +localization there just percentage of + + + align:start position:0% +localization there just percentage of +destruction + + align:start position:0% +destruction + + + align:start position:0% +destruction +and on the ordinate he's plotting the + + align:start position:0% +and on the ordinate he's plotting the + + + align:start position:0% +and on the ordinate he's plotting the +errors + + align:start position:0% +errors + + + align:start position:0% +errors +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and at least for maze 3 where it's very + + align:start position:0% +and at least for maze 3 where it's very + + + align:start position:0% +and at least for maze 3 where it's very +clear that's the most complex maze + + align:start position:0% +clear that's the most complex maze + + + align:start position:0% +clear that's the most complex maze +okay it's very clear that + + align:start position:0% +okay it's very clear that + + + align:start position:0% +okay it's very clear that +if he makes larger lesions he's + + align:start position:0% +if he makes larger lesions he's + + + align:start position:0% +if he makes larger lesions he's +disturbing the learning a lot they make + + align:start position:0% +disturbing the learning a lot they make + + + align:start position:0% +disturbing the learning a lot they make +many more errors + + align:start position:0% + + + + align:start position:0% + +he claimed + + align:start position:0% +he claimed + + + align:start position:0% +he claimed +that + + align:start position:0% +that + + + align:start position:0% +that +it didn't make any difference + + align:start position:0% +it didn't make any difference + + + align:start position:0% +it didn't make any difference +where the lesion was + + align:start position:0% +where the lesion was + + + align:start position:0% +where the lesion was +that anterior lesions + + align:start position:0% +that anterior lesions + + + align:start position:0% +that anterior lesions +if they were of a certain size produced + + align:start position:0% +if they were of a certain size produced + + + align:start position:0% +if they were of a certain size produced +about the same disturbance + + align:start position:0% +about the same disturbance + + + align:start position:0% +about the same disturbance +of the memory of the animal as the + + align:start position:0% +of the memory of the animal as the + + + align:start position:0% +of the memory of the animal as the +posteriorly + + align:start position:0% +posteriorly + + + align:start position:0% +posteriorly +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and similarly for other localizations + + align:start position:0% +and similarly for other localizations + + + align:start position:0% +and similarly for other localizations +he said that in that respect the + + align:start position:0% +he said that in that respect the + + + align:start position:0% +he said that in that respect the +neocortex was equi-potential for + + align:start position:0% +neocortex was equi-potential for + + + align:start position:0% +neocortex was equi-potential for +may's learning + + align:start position:0% + + + + align:start position:0% + +that's his principle of equipotentiality + + align:start position:0% +that's his principle of equipotentiality + + + align:start position:0% +that's his principle of equipotentiality +and he said it + + align:start position:0% +and he said it + + + align:start position:0% +and he said it +to learn the maze the animal what the + + align:start position:0% +to learn the maze the animal what the + + + align:start position:0% +to learn the maze the animal what the +rat needed was a certain quantity of + + align:start position:0% +rat needed was a certain quantity of + + + align:start position:0% +rat needed was a certain quantity of +cortex and the more he had the better + + align:start position:0% +cortex and the more he had the better + + + align:start position:0% +cortex and the more he had the better +okay that was his principle of mass + + align:start position:0% +okay that was his principle of mass + + + align:start position:0% +okay that was his principle of mass +action + + align:start position:0% +action + + + align:start position:0% +action +they mean almost the same thing + + align:start position:0% +they mean almost the same thing + + + align:start position:0% +they mean almost the same thing +okay + + align:start position:0% + + + + align:start position:0% + +so that was his conclusion and he wrote + + align:start position:0% +so that was his conclusion and he wrote + + + align:start position:0% +so that was his conclusion and he wrote +a book about it + + align:start position:0% +a book about it + + + align:start position:0% +a book about it +published in the late 20s + + align:start position:0% +published in the late 20s + + + align:start position:0% +published in the late 20s +and that remained + + align:start position:0% +and that remained + + + align:start position:0% +and that remained +and it was often cited because of its + + align:start position:0% +and it was often cited because of its + + + align:start position:0% +and it was often cited because of its +beautiful methodology + + align:start position:0% +beautiful methodology + + + align:start position:0% +beautiful methodology +until + + align:start position:0% +until + + + align:start position:0% +until +these irreverent people at mit + + align:start position:0% +these irreverent people at mit + + + align:start position:0% +these irreverent people at mit +in 1965 decided to re-analyze lashley's + + align:start position:0% +in 1965 decided to re-analyze lashley's + + + align:start position:0% +in 1965 decided to re-analyze lashley's +experiment + + align:start position:0% +experiment + + + align:start position:0% +experiment +charlie gross the first author + + align:start position:0% +charlie gross the first author + + + align:start position:0% +charlie gross the first author +is + + align:start position:0% +is + + + align:start position:0% +is +moved to princeton after that and + + align:start position:0% +moved to princeton after that and + + + align:start position:0% +moved to princeton after that and +actually moved to harvard first then + + align:start position:0% +actually moved to harvard first then + + + align:start position:0% +actually moved to harvard first then +princeton + + align:start position:0% +princeton + + + align:start position:0% +princeton +steve sharper is retired + + align:start position:0% +steve sharper is retired + + + align:start position:0% +steve sharper is retired +from our faculty not too long ago and + + align:start position:0% +from our faculty not too long ago and + + + align:start position:0% +from our faculty not too long ago and +cohen was one of their + + align:start position:0% +cohen was one of their + + + align:start position:0% +cohen was one of their +graduate students + + align:start position:0% + + + + align:start position:0% + +they thought that + + align:start position:0% +they thought that + + + align:start position:0% +they thought that +he was probably what they looked at his + + align:start position:0% +he was probably what they looked at his + + + align:start position:0% +he was probably what they looked at his +lesions they said he was probably + + align:start position:0% +lesions they said he was probably + + + align:start position:0% +lesions they said he was probably +disturbing two distinct functions that + + align:start position:0% +disturbing two distinct functions that + + + align:start position:0% +disturbing two distinct functions that +were both needed for solving his mazes + + align:start position:0% +were both needed for solving his mazes + + + align:start position:0% +were both needed for solving his mazes +one was visual abilities + + align:start position:0% +one was visual abilities + + + align:start position:0% +one was visual abilities +which depend on this area + + align:start position:0% +which depend on this area + + + align:start position:0% +which depend on this area +back here this is the visual cortex + + align:start position:0% +back here this is the visual cortex + + + align:start position:0% +back here this is the visual cortex +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and it's often called area 17 + + align:start position:0% + + + + align:start position:0% + +or striat cortex + + align:start position:0% +or striat cortex + + + align:start position:0% +or striat cortex +and the other area + + align:start position:0% +and the other area + + + align:start position:0% +and the other area +they felt he was disturbing was this + + align:start position:0% +they felt he was disturbing was this + + + align:start position:0% +they felt he was disturbing was this +region anterior to the motor cortex + + align:start position:0% +region anterior to the motor cortex + + + align:start position:0% +region anterior to the motor cortex +again bilaterally + + align:start position:0% +again bilaterally + + + align:start position:0% +again bilaterally +prefrontal cortex + + align:start position:0% + + + + align:start position:0% + +now why + + align:start position:0% +now why + + + align:start position:0% +now why +that + + align:start position:0% +that + + + align:start position:0% +that +was known in in studies done shortly + + align:start position:0% +was known in in studies done shortly + + + align:start position:0% +was known in in studies done shortly +before this to be important for + + align:start position:0% +before this to be important for + + + align:start position:0% +before this to be important for +learning to alternate left + + align:start position:0% +learning to alternate left + + + align:start position:0% +learning to alternate left +turns and right turns + + align:start position:0% +turns and right turns + + + align:start position:0% +turns and right turns +and if you look at this maze + + align:start position:0% +and if you look at this maze + + + align:start position:0% +and if you look at this maze +you can see that + + align:start position:0% +you can see that + + + align:start position:0% +you can see that +these mazes depend on the rats being + + align:start position:0% +these mazes depend on the rats being + + + align:start position:0% +these mazes depend on the rats being +able to learn to turn one way and then + + align:start position:0% +able to learn to turn one way and then + + + align:start position:0% +able to learn to turn one way and then +the other you see the top maze there is + + align:start position:0% +the other you see the top maze there is + + + align:start position:0% +the other you see the top maze there is +to turn right then left and right and + + align:start position:0% +to turn right then left and right and + + + align:start position:0% +to turn right then left and right and +left then right to get into the food box + + align:start position:0% +left then right to get into the food box + + + align:start position:0% +left then right to get into the food box +so maybe and they did separate tests of + + align:start position:0% +so maybe and they did separate tests of + + + align:start position:0% +so maybe and they did separate tests of +that themselves + + align:start position:0% +that themselves + + + align:start position:0% +that themselves +and they showed that + + align:start position:0% +and they showed that + + + align:start position:0% +and they showed that +if they made lesions + + align:start position:0% +if they made lesions + + + align:start position:0% +if they made lesions +of that anterior area + + align:start position:0% +of that anterior area + + + align:start position:0% +of that anterior area +and compared it with lesions the posture + + align:start position:0% +and compared it with lesions the posture + + + align:start position:0% +and compared it with lesions the posture +area it disturbed only the ability to + + align:start position:0% +area it disturbed only the ability to + + + align:start position:0% +area it disturbed only the ability to +alternate it didn't disturb visual + + align:start position:0% +alternate it didn't disturb visual + + + align:start position:0% +alternate it didn't disturb visual +discrimination abilities they had + + align:start position:0% +discrimination abilities they had + + + align:start position:0% +discrimination abilities they had +separate tests + + align:start position:0% +separate tests + + + align:start position:0% +separate tests +for visual discrimination discrimination + + align:start position:0% +for visual discrimination discrimination + + + align:start position:0% +for visual discrimination discrimination +of patterns + + align:start position:0% +of patterns + + + align:start position:0% +of patterns +that depends on the visual cortex but + + align:start position:0% +that depends on the visual cortex but + + + align:start position:0% +that depends on the visual cortex but +not on that anterior area + + align:start position:0% + + + + align:start position:0% + +okay so and they demonstrated this also + + align:start position:0% +okay so and they demonstrated this also + + + align:start position:0% +okay so and they demonstrated this also +with they had a series of mazes + + align:start position:0% +with they had a series of mazes + + + align:start position:0% +with they had a series of mazes +that they found to be quite dependent on + + align:start position:0% +that they found to be quite dependent on + + + align:start position:0% +that they found to be quite dependent on +the visual cortex + + align:start position:0% +the visual cortex + + + align:start position:0% +the visual cortex +and they had a separate test of + + align:start position:0% +and they had a separate test of + + + align:start position:0% +and they had a separate test of +alternation and didn't involve mazes at + + align:start position:0% +alternation and didn't involve mazes at + + + align:start position:0% +alternation and didn't involve mazes at +all but involved pressing a bar the left + + align:start position:0% +all but involved pressing a bar the left + + + align:start position:0% +all but involved pressing a bar the left +bar then the right bar and the left bar + + align:start position:0% +bar then the right bar and the left bar + + + align:start position:0% +bar then the right bar and the left bar +on the right bar and so forth + + align:start position:0% + + + + align:start position:0% + +so they showed that these two functions + + align:start position:0% +so they showed that these two functions + + + align:start position:0% +so they showed that these two functions +were disturbed separately + + align:start position:0% + + + + align:start position:0% + +and they can these two functions can be + + align:start position:0% +and they can these two functions can be + + + align:start position:0% +and they can these two functions can be +dissociated + + align:start position:0% + + + + align:start position:0% + +by these lesions + + align:start position:0% +by these lesions + + + align:start position:0% +by these lesions +so they concluded that last week's + + align:start position:0% +so they concluded that last week's + + + align:start position:0% +so they concluded that last week's +interpretation was incorrect and in fact + + align:start position:0% +interpretation was incorrect and in fact + + + align:start position:0% +interpretation was incorrect and in fact +after lashley's work + + align:start position:0% +after lashley's work + + + align:start position:0% +after lashley's work +a man named hunter argued + + align:start position:0% +a man named hunter argued + + + align:start position:0% +a man named hunter argued +fairly in a fairly similar way he said + + align:start position:0% +fairly in a fairly similar way he said + + + align:start position:0% +fairly in a fairly similar way he said +that + + align:start position:0% +that + + + align:start position:0% +that +may's learning is such a complex + + align:start position:0% +may's learning is such a complex + + + align:start position:0% +may's learning is such a complex +function the rat is using + + align:start position:0% +function the rat is using + + + align:start position:0% +function the rat is using +many different senses + + align:start position:0% +many different senses + + + align:start position:0% +many different senses +he's probably using olfaction somatic + + align:start position:0% +he's probably using olfaction somatic + + + align:start position:0% +he's probably using olfaction somatic +sensation so forth + + align:start position:0% +sensation so forth + + + align:start position:0% +sensation so forth +he didn't know about this dependence of + + align:start position:0% +he didn't know about this dependence of + + + align:start position:0% +he didn't know about this dependence of +alternation on the frontal cortex he + + align:start position:0% +alternation on the frontal cortex he + + + align:start position:0% +alternation on the frontal cortex he +probably did know about the visual + + align:start position:0% +probably did know about the visual + + + align:start position:0% +probably did know about the visual +cortex and vision + + align:start position:0% +cortex and vision + + + align:start position:0% +cortex and vision +and hunter argued that ashley was + + align:start position:0% +and hunter argued that ashley was + + + align:start position:0% +and hunter argued that ashley was +probably with his lesions just + + align:start position:0% +probably with his lesions just + + + align:start position:0% +probably with his lesions just +disturbing to varying degrees + + align:start position:0% +disturbing to varying degrees + + + align:start position:0% +disturbing to varying degrees +different senses + + align:start position:0% +different senses + + + align:start position:0% +different senses +all which + + align:start position:0% +all which + + + align:start position:0% +all which +were used in maze learning + + align:start position:0% + + + + align:start position:0% + +but together the hunter arguments + + align:start position:0% +but together the hunter arguments + + + align:start position:0% +but together the hunter arguments +who and what under always lost the + + align:start position:0% +who and what under always lost the + + + align:start position:0% +who and what under always lost the +debates to lashley lashley was a very + + align:start position:0% +debates to lashley lashley was a very + + + align:start position:0% +debates to lashley lashley was a very +good debater + + align:start position:0% + + + + align:start position:0% + +so that's why this + + align:start position:0% +so that's why this + + + align:start position:0% +so that's why this +study was needed + + align:start position:0% + + + + align:start position:0% + +so now we still recognize lashley for + + align:start position:0% +so now we still recognize lashley for + + + align:start position:0% +so now we still recognize lashley for +his methodology but not for + + align:start position:0% +his methodology but not for + + + align:start position:0% +his methodology but not for +his analysis of that particular + + align:start position:0% +his analysis of that particular + + + align:start position:0% +his analysis of that particular +experiment + + align:start position:0% + + + + align:start position:0% + +the keys to that kind of problem are + + align:start position:0% +the keys to that kind of problem are + + + align:start position:0% +the keys to that kind of problem are +these + + align:start position:0% +these + + + align:start position:0% +these +you need both near anatomical knowledge + + align:start position:0% +you need both near anatomical knowledge + + + align:start position:0% +you need both near anatomical knowledge +and behavioral knowledge + + align:start position:0% +and behavioral knowledge + + + align:start position:0% +and behavioral knowledge +lashley didn't have adequate behavioral + + align:start position:0% +lashley didn't have adequate behavioral + + + align:start position:0% +lashley didn't have adequate behavioral +knowledge + + align:start position:0% +knowledge + + + align:start position:0% +knowledge +about the functions he was + + align:start position:0% +about the functions he was + + + align:start position:0% +about the functions he was +the rat might be using to solve those + + align:start position:0% +the rat might be using to solve those + + + align:start position:0% +the rat might be using to solve those +mazes + + align:start position:0% +mazes + + + align:start position:0% +mazes +did later do + + align:start position:0% +did later do + + + align:start position:0% +did later do +more neuroanatomy and came to + + align:start position:0% +more neuroanatomy and came to + + + align:start position:0% +more neuroanatomy and came to +he actually studied the localization of + + align:start position:0% +he actually studied the localization of + + + align:start position:0% +he actually studied the localization of +the visual cortex in the rat + + align:start position:0% +the visual cortex in the rat + + + align:start position:0% +the visual cortex in the rat +and so he did come to understand + + align:start position:0% +and so he did come to understand + + + align:start position:0% +and so he did come to understand +that posterior localization + + align:start position:0% +that posterior localization + + + align:start position:0% +that posterior localization +of the + + align:start position:0% +of the + + + align:start position:0% +of the +area that + + align:start position:0% +area that + + + align:start position:0% +area that +is most closely connected + + align:start position:0% +is most closely connected + + + align:start position:0% +is most closely connected +to the to the retina + + align:start position:0% +to the to the retina + + + align:start position:0% +to the to the retina +through a pathway that's become well + + align:start position:0% +through a pathway that's become well + + + align:start position:0% +through a pathway that's become well +known + + align:start position:0% +known + + + align:start position:0% +known +was only becoming well known at the time + + align:start position:0% +was only becoming well known at the time + + + align:start position:0% +was only becoming well known at the time +of lashley + + align:start position:0% +of lashley + + + align:start position:0% +of lashley +last year's experiments + + align:start position:0% + + + + align:start position:0% + +so you need both kinds of knowledge to + + align:start position:0% +so you need both kinds of knowledge to + + + align:start position:0% +so you need both kinds of knowledge to +do that and + + align:start position:0% +do that and + + + align:start position:0% +do that and +even when i was in graduate school + + align:start position:0% +even when i was in graduate school + + + align:start position:0% +even when i was in graduate school +which is a long time ago + + align:start position:0% +which is a long time ago + + + align:start position:0% +which is a long time ago +1960s + + align:start position:0% +1960s + + + align:start position:0% +1960s +the + + align:start position:0% +the + + + align:start position:0% +the +many people were still doing this kind + + align:start position:0% +many people were still doing this kind + + + align:start position:0% +many people were still doing this kind +of lesion study with + + align:start position:0% +of lesion study with + + + align:start position:0% +of lesion study with +very little neuroanatomy + + align:start position:0% +very little neuroanatomy + + + align:start position:0% +very little neuroanatomy +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and they they didn't worry much about + + align:start position:0% +and they they didn't worry much about + + + align:start position:0% +and they they didn't worry much about +connections in the brain they weren't + + align:start position:0% +connections in the brain they weren't + + + align:start position:0% +connections in the brain they weren't +interpreting they were thinking of + + align:start position:0% +interpreting they were thinking of + + + align:start position:0% +interpreting they were thinking of +localization of function without + + align:start position:0% +localization of function without + + + align:start position:0% +localization of function without +thinking about the connections involved + + align:start position:0% +thinking about the connections involved + + + align:start position:0% +thinking about the connections involved +and that was a major problem + + align:start position:0% +and that was a major problem + + + align:start position:0% +and that was a major problem +i'll give you one other example there + + align:start position:0% +i'll give you one other example there + + + align:start position:0% +i'll give you one other example there +we'll show you this kind of problem + + align:start position:0% +we'll show you this kind of problem + + + align:start position:0% +we'll show you this kind of problem +especially with + + align:start position:0% +especially with + + + align:start position:0% +especially with +knowing the behavior + + align:start position:0% + + + + align:start position:0% + +because neuroscience is studying + + align:start position:0% +because neuroscience is studying + + + align:start position:0% +because neuroscience is studying +branding behavior + + align:start position:0% +branding behavior + + + align:start position:0% +branding behavior +i would say that + + align:start position:0% +i would say that + + + align:start position:0% +i would say that +with all the advances in + + align:start position:0% +with all the advances in + + + align:start position:0% +with all the advances in +anatomy and physiology + + align:start position:0% +anatomy and physiology + + + align:start position:0% +anatomy and physiology +behavioral knowledge is still often legs + + align:start position:0% +behavioral knowledge is still often legs + + + align:start position:0% +behavioral knowledge is still often legs +behind a little bit let me give you one + + align:start position:0% +behind a little bit let me give you one + + + align:start position:0% +behind a little bit let me give you one +example + + align:start position:0% +example + + + align:start position:0% +example +a claim developed + + align:start position:0% + + + + align:start position:0% + +findings that were done in the + + align:start position:0% +findings that were done in the + + + align:start position:0% +findings that were done in the +experiments at rutgers mainly where the + + align:start position:0% +experiments at rutgers mainly where the + + + align:start position:0% +experiments at rutgers mainly where the +claim was made that sexual ability + + align:start position:0% +claim was made that sexual ability + + + align:start position:0% +claim was made that sexual ability +is located in the neocortex + + align:start position:0% +is located in the neocortex + + + align:start position:0% +is located in the neocortex +in the male rat but not the female + + align:start position:0% +in the male rat but not the female + + + align:start position:0% +in the male rat but not the female +how did they come to that conclusion + + align:start position:0% +how did they come to that conclusion + + + align:start position:0% +how did they come to that conclusion +well very simple + + align:start position:0% +well very simple + + + align:start position:0% +well very simple +they they did lesions like lashley + + align:start position:0% +they they did lesions like lashley + + + align:start position:0% +they they did lesions like lashley +okay + + align:start position:0% +okay + + + align:start position:0% +okay +lesions of varying size in the neocortex + + align:start position:0% +lesions of varying size in the neocortex + + + align:start position:0% +lesions of varying size in the neocortex +and they did it in both male rats and + + align:start position:0% +and they did it in both male rats and + + + align:start position:0% +and they did it in both male rats and +female rats + + align:start position:0% + + + + align:start position:0% + +and then they had a very simple test of + + align:start position:0% +and then they had a very simple test of + + + align:start position:0% +and then they had a very simple test of +sexual behavior they simply observed + + align:start position:0% +sexual behavior they simply observed + + + align:start position:0% +sexual behavior they simply observed +whether the animals would copulate or + + align:start position:0% +whether the animals would copulate or + + + align:start position:0% +whether the animals would copulate or +not and they found that the females + + align:start position:0% +not and they found that the females + + + align:start position:0% +not and they found that the females +would still go into the lordosis posture + + align:start position:0% +would still go into the lordosis posture + + + align:start position:0% +would still go into the lordosis posture +and accept the male rat + + align:start position:0% +and accept the male rat + + + align:start position:0% +and accept the male rat +and the rat the male rats if they had + + align:start position:0% +and the rat the male rats if they had + + + align:start position:0% +and the rat the male rats if they had +much neocortex missing failed to + + align:start position:0% +much neocortex missing failed to + + + align:start position:0% +much neocortex missing failed to +copulate + + align:start position:0% +copulate + + + align:start position:0% +copulate +so very simple they said neocortex + + align:start position:0% +so very simple they said neocortex + + + align:start position:0% +so very simple they said neocortex +is needed for sexual behavior in the + + align:start position:0% +is needed for sexual behavior in the + + + align:start position:0% +is needed for sexual behavior in the +male and not the female + + align:start position:0% +male and not the female + + + align:start position:0% +male and not the female +of course everybody thought well let's + + align:start position:0% +of course everybody thought well let's + + + align:start position:0% +of course everybody thought well let's +see it's a higher function in the male + + align:start position:0% +see it's a higher function in the male + + + align:start position:0% +see it's a higher function in the male +not the female + + align:start position:0% +not the female + + + align:start position:0% +not the female +what was wrong with that + + align:start position:0% +what was wrong with that + + + align:start position:0% +what was wrong with that +well + + align:start position:0% +well + + + align:start position:0% +well +you've got to think about the behavior + + align:start position:0% +you've got to think about the behavior + + + align:start position:0% +you've got to think about the behavior +they didn't understand + + align:start position:0% +they didn't understand + + + align:start position:0% +they didn't understand +sexual behavior in the female at all + + align:start position:0% +sexual behavior in the female at all + + + align:start position:0% +sexual behavior in the female at all +all they understood was this posture + + align:start position:0% +all they understood was this posture + + + align:start position:0% +all they understood was this posture +that the animal entered + + align:start position:0% +that the animal entered + + + align:start position:0% +that the animal entered +the equivalent in the male would be say + + align:start position:0% +the equivalent in the male would be say + + + align:start position:0% +the equivalent in the male would be say +the ejaculation reflex + + align:start position:0% +the ejaculation reflex + + + align:start position:0% +the ejaculation reflex +that wasn't disturbed after the + + align:start position:0% +that wasn't disturbed after the + + + align:start position:0% +that wasn't disturbed after the +neocortical lesions + + align:start position:0% +neocortical lesions + + + align:start position:0% +neocortical lesions +what they were disturbing was the + + align:start position:0% +what they were disturbing was the + + + align:start position:0% +what they were disturbing was the +ability of the rat the male rat to + + align:start position:0% +ability of the rat the male rat to + + + align:start position:0% +ability of the rat the male rat to +orient to the females to find her to + + align:start position:0% +orient to the females to find her to + + + align:start position:0% +orient to the females to find her to +position himself properly and so forth + + align:start position:0% +position himself properly and so forth + + + align:start position:0% +position himself properly and so forth +that involves a lot of + + align:start position:0% +that involves a lot of + + + align:start position:0% +that involves a lot of +sensory motor control they were + + align:start position:0% +sensory motor control they were + + + align:start position:0% +sensory motor control they were +disturbing the senses + + align:start position:0% +disturbing the senses + + + align:start position:0% +disturbing the senses +and motor control by making those + + align:start position:0% +and motor control by making those + + + align:start position:0% +and motor control by making those +lesions but what about the female + + align:start position:0% +lesions but what about the female + + + align:start position:0% +lesions but what about the female +well if they only look at the end point + + align:start position:0% +well if they only look at the end point + + + align:start position:0% +well if they only look at the end point +they're missing solicitation behavior + + align:start position:0% +they're missing solicitation behavior + + + align:start position:0% +they're missing solicitation behavior +mate choice a lot of + + align:start position:0% +mate choice a lot of + + + align:start position:0% +mate choice a lot of +things we know about sexual behavior of + + align:start position:0% +things we know about sexual behavior of + + + align:start position:0% +things we know about sexual behavior of +female + + align:start position:0% +female + + + align:start position:0% +female +rodents and many other animals almost + + align:start position:0% +rodents and many other animals almost + + + align:start position:0% +rodents and many other animals almost +all animals okay because they weren't + + align:start position:0% +all animals okay because they weren't + + + align:start position:0% +all animals okay because they weren't +good ethologists + + align:start position:0% +good ethologists + + + align:start position:0% +good ethologists +they didn't + + align:start position:0% +they didn't + + + align:start position:0% +they didn't +look at the behavior in any + + align:start position:0% +look at the behavior in any + + + align:start position:0% +look at the behavior in any +comprehensive way + + align:start position:0% +comprehensive way + + + align:start position:0% +comprehensive way +so they made the same kind of mistake + + align:start position:0% +so they made the same kind of mistake + + + align:start position:0% +so they made the same kind of mistake +well a somewhat different kind of + + align:start position:0% +well a somewhat different kind of + + + align:start position:0% +well a somewhat different kind of +mistake from what i actually made + + align:start position:0% +mistake from what i actually made + + + align:start position:0% +mistake from what i actually made +i just want to point out that when you + + align:start position:0% +i just want to point out that when you + + + align:start position:0% +i just want to point out that when you +read these kinds of claims in the + + align:start position:0% +read these kinds of claims in the + + + align:start position:0% +read these kinds of claims in the +literature + + align:start position:0% +literature + + + align:start position:0% +literature +you've got to think about + + align:start position:0% +you've got to think about + + + align:start position:0% +you've got to think about +whether they adequately dealt with + + align:start position:0% +whether they adequately dealt with + + + align:start position:0% +whether they adequately dealt with +both anatomical knowledge and behavioral + + align:start position:0% +both anatomical knowledge and behavioral + + + align:start position:0% +both anatomical knowledge and behavioral +knowledge before you just believe it + + align:start position:0% + + + + align:start position:0% + +concerning the memory problem + + align:start position:0% +concerning the memory problem + + + align:start position:0% +concerning the memory problem +i like to tell this story + + align:start position:0% +i like to tell this story + + + align:start position:0% +i like to tell this story +about + + align:start position:0% +about + + + align:start position:0% +about +my first visit to a telephone switching + + align:start position:0% +my first visit to a telephone switching + + + align:start position:0% +my first visit to a telephone switching +station + + align:start position:0% +station + + + align:start position:0% +station +in the middle of the + + align:start position:0% +in the middle of the + + + align:start position:0% +in the middle of the +well it was probably about 40 years ago + + align:start position:0% +well it was probably about 40 years ago + + + align:start position:0% +well it was probably about 40 years ago +my brother was running one of these + + align:start position:0% +my brother was running one of these + + + align:start position:0% +my brother was running one of these +stations for + + align:start position:0% +stations for + + + align:start position:0% +stations for +the telephone a large the large + + align:start position:0% +the telephone a large the large + + + align:start position:0% +the telephone a large the large +telephone company was the only one at + + align:start position:0% +telephone company was the only one at + + + align:start position:0% +telephone company was the only one at +the time bell telephone and + + align:start position:0% +the time bell telephone and + + + align:start position:0% +the time bell telephone and +they + + align:start position:0% +they + + + align:start position:0% +they +inside the station you saw this enormous + + align:start position:0% +inside the station you saw this enormous + + + align:start position:0% +inside the station you saw this enormous +amount of machinery they were basically + + align:start position:0% +amount of machinery they were basically + + + align:start position:0% +amount of machinery they were basically +relays + + align:start position:0% +relays + + + align:start position:0% +relays +connected with wires coming from these + + align:start position:0% +connected with wires coming from these + + + align:start position:0% +connected with wires coming from these +large cables from outside enormous + + align:start position:0% +large cables from outside enormous + + + align:start position:0% +large cables from outside enormous +numbers of wires + + align:start position:0% +numbers of wires + + + align:start position:0% +numbers of wires +and i + + align:start position:0% + + + + align:start position:0% + +i wasn't + + align:start position:0% +i wasn't + + + align:start position:0% +i wasn't +an electrical engineer + + align:start position:0% +an electrical engineer + + + align:start position:0% +an electrical engineer +but + + align:start position:0% +but + + + align:start position:0% +but +i understood something about circuits + + align:start position:0% +i understood something about circuits + + + align:start position:0% +i understood something about circuits +and i was learning about the brain so i + + align:start position:0% +and i was learning about the brain so i + + + align:start position:0% +and i was learning about the brain so i +asked him where's the + + align:start position:0% +asked him where's the + + + align:start position:0% +asked him where's the +input and he showed me the input cables + + align:start position:0% +input and he showed me the input cables + + + align:start position:0% +input and he showed me the input cables +coming in where's the output + + align:start position:0% +coming in where's the output + + + align:start position:0% +coming in where's the output +he showed me that enormous amounts of + + align:start position:0% +he showed me that enormous amounts of + + + align:start position:0% +he showed me that enormous amounts of +machinery involved in this i said but + + align:start position:0% +machinery involved in this i said but + + + align:start position:0% +machinery involved in this i said but +there's another problem how do you + + align:start position:0% +there's another problem how do you + + + align:start position:0% +there's another problem how do you +remember who's calling who so you can + + align:start position:0% +remember who's calling who so you can + + + align:start position:0% +remember who's calling who so you can +build them + + align:start position:0% +build them + + + align:start position:0% +build them +and he said oh that's over there it was + + align:start position:0% +and he said oh that's over there it was + + + align:start position:0% +and he said oh that's over there it was +this little device + + align:start position:0% +this little device + + + align:start position:0% +this little device +you know obviously using a different + + align:start position:0% +you know obviously using a different + + + align:start position:0% +you know obviously using a different +kind of circuitry a little tiny thing + + align:start position:0% +kind of circuitry a little tiny thing + + + align:start position:0% +kind of circuitry a little tiny thing +in one part of the room that he said did + + align:start position:0% +in one part of the room that he said did + + + align:start position:0% +in one part of the room that he said did +all the + + align:start position:0% +all the + + + align:start position:0% +all the +all the memory functions + + align:start position:0% +all the memory functions + + + align:start position:0% +all the memory functions +and it made me realize that probably in + + align:start position:0% +and it made me realize that probably in + + + align:start position:0% +and it made me realize that probably in +the brain it's something similar in the + + align:start position:0% +the brain it's something similar in the + + + align:start position:0% +the brain it's something similar in the +neocortex a lot of the cortical + + align:start position:0% +neocortex a lot of the cortical + + + align:start position:0% +neocortex a lot of the cortical +apparatus is involved in sensory + + align:start position:0% +apparatus is involved in sensory + + + align:start position:0% +apparatus is involved in sensory +analysis + + align:start position:0% +analysis + + + align:start position:0% +analysis +and motor coordination + + align:start position:0% +and motor coordination + + + align:start position:0% +and motor coordination +okay + + align:start position:0% +okay + + + align:start position:0% +okay +memory could be distributed or it could + + align:start position:0% +memory could be distributed or it could + + + align:start position:0% +memory could be distributed or it could +be localized but it could be much more + + align:start position:0% +be localized but it could be much more + + + align:start position:0% +be localized but it could be much more +difficult + + align:start position:0% +difficult + + + align:start position:0% +difficult +to deal with and of course that proved + + align:start position:0% +to deal with and of course that proved + + + align:start position:0% +to deal with and of course that proved +to be true with the ensuing years + + align:start position:0% +to be true with the ensuing years + + + align:start position:0% +to be true with the ensuing years +but now we're beginning to get a much + + align:start position:0% +but now we're beginning to get a much + + + align:start position:0% +but now we're beginning to get a much +better handle on that as well + + align:start position:0% + + + + align:start position:0% + +when we deal with this problem of + + align:start position:0% +when we deal with this problem of + + + align:start position:0% +when we deal with this problem of +localization of function + + align:start position:0% + + + + align:start position:0% + +you have to think about the question + + align:start position:0% +you have to think about the question + + + align:start position:0% +you have to think about the question +what is localized + + align:start position:0% +what is localized + + + align:start position:0% +what is localized +what are we trying to localize is it a + + align:start position:0% +what are we trying to localize is it a + + + align:start position:0% +what are we trying to localize is it a +conscious entity is it + + align:start position:0% +conscious entity is it + + + align:start position:0% +conscious entity is it +a psychological ability is it memory + + align:start position:0% + + + + align:start position:0% + +my answer is that no those are + + align:start position:0% +my answer is that no those are + + + align:start position:0% +my answer is that no those are +not brain words + + align:start position:0% + + + + align:start position:0% + +you have to be very wary when you read + + align:start position:0% +you have to be very wary when you read + + + align:start position:0% +you have to be very wary when you read +about centers for pleasure the pleasure + + align:start position:0% +about centers for pleasure the pleasure + + + align:start position:0% +about centers for pleasure the pleasure +center the sex center the hunger center + + align:start position:0% +center the sex center the hunger center + + + align:start position:0% +center the sex center the hunger center +the center for mental arithmetic or + + align:start position:0% +the center for mental arithmetic or + + + align:start position:0% +the center for mental arithmetic or +whatever + + align:start position:0% +whatever + + + align:start position:0% +whatever +because those are + + align:start position:0% +because those are + + + align:start position:0% +because those are +psychological functions + + align:start position:0% +psychological functions + + + align:start position:0% +psychological functions +that's not what's localized + + align:start position:0% +that's not what's localized + + + align:start position:0% +that's not what's localized +what's localized is + + align:start position:0% +what's localized is + + + align:start position:0% +what's localized is +physical or physiological processes in a + + align:start position:0% +physical or physiological processes in a + + + align:start position:0% +physical or physiological processes in a +structural substrate + + align:start position:0% +structural substrate + + + align:start position:0% +structural substrate +we're never going to find the ghost in + + align:start position:0% +we're never going to find the ghost in + + + align:start position:0% +we're never going to find the ghost in +the machine + + align:start position:0% +the machine + + + align:start position:0% +the machine +it's not there + + align:start position:0% + + + + align:start position:0% + +you're going to find the input pathways + + align:start position:0% +you're going to find the input pathways + + + align:start position:0% +you're going to find the input pathways +you're going to find output pathways + + align:start position:0% +you're going to find output pathways + + + align:start position:0% +you're going to find output pathways +you're going to find + + align:start position:0% +you're going to find + + + align:start position:0% +you're going to find +processing + + align:start position:0% +processing + + + align:start position:0% +processing +connections in the intermediate network + + align:start position:0% +connections in the intermediate network + + + align:start position:0% +connections in the intermediate network +okay + + align:start position:0% + + + + align:start position:0% + +luria the russian + + align:start position:0% + + + + align:start position:0% + +neuropsychologist the great + + align:start position:0% +neuropsychologist the great + + + align:start position:0% +neuropsychologist the great +neuropsychologist in the + + align:start position:0% +neuropsychologist in the + + + align:start position:0% +neuropsychologist in the +last century + + align:start position:0% + + + + align:start position:0% + +had this state has this statement in one + + align:start position:0% +had this state has this statement in one + + + align:start position:0% +had this state has this statement in one +of his works on neuropsychology he said + + align:start position:0% +of his works on neuropsychology he said + + + align:start position:0% +of his works on neuropsychology he said +that mental functions is complex + + align:start position:0% +that mental functions is complex + + + align:start position:0% +that mental functions is complex +functional systems cannot be localized + + align:start position:0% +functional systems cannot be localized + + + align:start position:0% +functional systems cannot be localized +in narrow zones of cortex or in isolated + + align:start position:0% +in narrow zones of cortex or in isolated + + + align:start position:0% +in narrow zones of cortex or in isolated +cell groups + + align:start position:0% +cell groups + + + align:start position:0% +cell groups +you see they involve a lot of apparatus + + align:start position:0% +you see they involve a lot of apparatus + + + align:start position:0% +you see they involve a lot of apparatus +you might disturb a function more with + + align:start position:0% +you might disturb a function more with + + + align:start position:0% +you might disturb a function more with +lesions in one place than another + + align:start position:0% +lesions in one place than another + + + align:start position:0% +lesions in one place than another +but the function as a whole you depend + + align:start position:0% +but the function as a whole you depend + + + align:start position:0% +but the function as a whole you depend +on + + align:start position:0% + + + + align:start position:0% + +a greater complexity of connections and + + align:start position:0% +a greater complexity of connections and + + + align:start position:0% +a greater complexity of connections and +that certainly + + align:start position:0% +that certainly + + + align:start position:0% +that certainly +remains true + + align:start position:0% + + + + align:start position:0% + +but if we go to the extreme we can say + + align:start position:0% +but if we go to the extreme we can say + + + align:start position:0% +but if we go to the extreme we can say +well don't brains think + + align:start position:0% + + + + align:start position:0% + +can't we say that thinking's localized + + align:start position:0% +can't we say that thinking's localized + + + align:start position:0% +can't we say that thinking's localized +in the brain + + align:start position:0% +in the brain + + + align:start position:0% +in the brain +makai who we met before + + align:start position:0% +makai who we met before + + + align:start position:0% +makai who we met before +said that this is a poor question + + align:start position:0% +said that this is a poor question + + + align:start position:0% +said that this is a poor question +because it mixes different conceptual + + align:start position:0% +because it mixes different conceptual + + + align:start position:0% +because it mixes different conceptual +levels + + align:start position:0% +levels + + + align:start position:0% +levels +and this is a statement from his paper a + + align:start position:0% +and this is a statement from his paper a + + + align:start position:0% +and this is a statement from his paper a +mind's eye view of the brain + + align:start position:0% +mind's eye view of the brain + + + align:start position:0% +mind's eye view of the brain +he says if we want to use language + + align:start position:0% +he says if we want to use language + + + align:start position:0% +he says if we want to use language +consistently we cannot say that brains + + align:start position:0% +consistently we cannot say that brains + + + align:start position:0% +consistently we cannot say that brains +think or decide + + align:start position:0% +think or decide + + + align:start position:0% +think or decide +brains do those physical things + + align:start position:0% +brains do those physical things + + + align:start position:0% +brains do those physical things +appropriate in their own logical + + align:start position:0% +appropriate in their own logical + + + align:start position:0% +appropriate in their own logical +dimensions as correlates of what people + + align:start position:0% +dimensions as correlates of what people + + + align:start position:0% +dimensions as correlates of what people +do + + align:start position:0% +do + + + align:start position:0% +do +like i say or animals when deciding + + align:start position:0% +like i say or animals when deciding + + + align:start position:0% +like i say or animals when deciding +thinking feeling hoping fearing bleeding + + align:start position:0% +thinking feeling hoping fearing bleeding + + + align:start position:0% +thinking feeling hoping fearing bleeding +so forth + + align:start position:0% + + + + align:start position:0% + +let's just talk briefly about the third + + align:start position:0% +let's just talk briefly about the third + + + align:start position:0% +let's just talk briefly about the third +type of goal + + align:start position:0% +type of goal + + + align:start position:0% +type of goal +of people + + align:start position:0% +of people + + + align:start position:0% +of people +that weren't + + align:start position:0% + + + + align:start position:0% + +necessarily concerned with reducing + + align:start position:0% +necessarily concerned with reducing + + + align:start position:0% +necessarily concerned with reducing +behavior to a specific circuit and they + + align:start position:0% +behavior to a specific circuit and they + + + align:start position:0% +behavior to a specific circuit and they +weren't necessarily concerned with + + align:start position:0% +weren't necessarily concerned with + + + align:start position:0% +weren't necessarily concerned with +localizing function but they're + + align:start position:0% +localizing function but they're + + + align:start position:0% +localizing function but they're +interested in correlating + + align:start position:0% +interested in correlating + + + align:start position:0% +interested in correlating +events of + + align:start position:0% +events of + + + align:start position:0% +events of +in the brain with behavioral events + + align:start position:0% + + + + align:start position:0% + +and i find this + + align:start position:0% + + + + align:start position:0% + +these attempts to correlate brand + + align:start position:0% +these attempts to correlate brand + + + align:start position:0% +these attempts to correlate brand +behavior to just be + + align:start position:0% +behavior to just be + + + align:start position:0% +behavior to just be +a never-ending fascination for people + + align:start position:0% +a never-ending fascination for people + + + align:start position:0% +a never-ending fascination for people +in fact they often forget that finding + + align:start position:0% +in fact they often forget that finding + + + align:start position:0% +in fact they often forget that finding +the correlation doesn't + + align:start position:0% +the correlation doesn't + + + align:start position:0% +the correlation doesn't +really prove causation at all + + align:start position:0% +really prove causation at all + + + align:start position:0% +really prove causation at all +and let's just give a few examples + + align:start position:0% +and let's just give a few examples + + + align:start position:0% +and let's just give a few examples +if we record with little electrodes + + align:start position:0% +if we record with little electrodes + + + align:start position:0% +if we record with little electrodes +placed on the scalp we can record very + + align:start position:0% +placed on the scalp we can record very + + + align:start position:0% +placed on the scalp we can record very +small potentials there that are changing + + align:start position:0% +small potentials there that are changing + + + align:start position:0% +small potentials there that are changing +okay because they're picking up + + align:start position:0% +okay because they're picking up + + + align:start position:0% +okay because they're picking up +currents are being induced by electrical + + align:start position:0% +currents are being induced by electrical + + + align:start position:0% +currents are being induced by electrical +changes in the underlying brain at least + + align:start position:0% +changes in the underlying brain at least + + + align:start position:0% +changes in the underlying brain at least +part just below the skull + + align:start position:0% + + + + align:start position:0% + +and we call those recordings the + + align:start position:0% +and we call those recordings the + + + align:start position:0% +and we call those recordings the +electron cephalograph + + align:start position:0% + + + + align:start position:0% + +it's usually put on a graph + + align:start position:0% +it's usually put on a graph + + + align:start position:0% +it's usually put on a graph +showing the amplitude of these waves + + align:start position:0% +showing the amplitude of these waves + + + align:start position:0% +showing the amplitude of these waves +picked up by different leads attached to + + align:start position:0% +picked up by different leads attached to + + + align:start position:0% +picked up by different leads attached to +the + + align:start position:0% +the + + + align:start position:0% +the +cortex the recording is pretty much the + + align:start position:0% +cortex the recording is pretty much the + + + align:start position:0% +cortex the recording is pretty much the +same as with electrocardiogram + + align:start position:0% +same as with electrocardiogram + + + align:start position:0% +same as with electrocardiogram +okay you're looking at electrolyte + + align:start position:0% +okay you're looking at electrolyte + + + align:start position:0% +okay you're looking at electrolyte +tissue the heart + + align:start position:0% + + + + align:start position:0% + +and we find that the pattern of what we + + align:start position:0% +and we find that the pattern of what we + + + align:start position:0% +and we find that the pattern of what we +we call those brain waves the pattern of + + align:start position:0% +we call those brain waves the pattern of + + + align:start position:0% +we call those brain waves the pattern of +those currents changes + + align:start position:0% +those currents changes + + + align:start position:0% +those currents changes +it's correlated with states of arousal + + align:start position:0% +it's correlated with states of arousal + + + align:start position:0% +it's correlated with states of arousal +or of sleep + + align:start position:0% +or of sleep + + + align:start position:0% +or of sleep +and that they're not localized functions + + align:start position:0% +and that they're not localized functions + + + align:start position:0% +and that they're not localized functions +but they appear to be they might be a + + align:start position:0% +but they appear to be they might be a + + + align:start position:0% +but they appear to be they might be a +little different and different than + + align:start position:0% +little different and different than + + + align:start position:0% +little different and different than +different leads but + + align:start position:0% +different leads but + + + align:start position:0% +different leads but +basically we're looking at + + align:start position:0% +basically we're looking at + + + align:start position:0% +basically we're looking at +states of the brain + + align:start position:0% +states of the brain + + + align:start position:0% +states of the brain +not at localized functions + + align:start position:0% +not at localized functions + + + align:start position:0% +not at localized functions +and that's fascinated people because + + align:start position:0% +and that's fascinated people because + + + align:start position:0% +and that's fascinated people because +when that was discovered now they had a + + align:start position:0% +when that was discovered now they had a + + + align:start position:0% +when that was discovered now they had a +way of looking at different stages of + + align:start position:0% +way of looking at different stages of + + + align:start position:0% +way of looking at different stages of +sleep and exploring you know what are + + align:start position:0% +sleep and exploring you know what are + + + align:start position:0% +sleep and exploring you know what are +the differences in different stages of + + align:start position:0% +the differences in different stages of + + + align:start position:0% +the differences in different stages of +sleep or in different states of arousal + + align:start position:0% +sleep or in different states of arousal + + + align:start position:0% +sleep or in different states of arousal +in the waking state + + align:start position:0% + + + + align:start position:0% + +so this kind of + + align:start position:0% +so this kind of + + + align:start position:0% +so this kind of +these attempts to correlate random + + align:start position:0% +these attempts to correlate random + + + align:start position:0% +these attempts to correlate random +behavior have led to some very different + + align:start position:0% +behavior have led to some very different + + + align:start position:0% +behavior have led to some very different +kinds of information + + align:start position:0% +kinds of information + + + align:start position:0% +kinds of information +about brain and behavior + + align:start position:0% +about brain and behavior + + + align:start position:0% +about brain and behavior +they led to the idea of states of the + + align:start position:0% +they led to the idea of states of the + + + align:start position:0% +they led to the idea of states of the +brain a hole where the brain can change + + align:start position:0% +brain a hole where the brain can change + + + align:start position:0% +brain a hole where the brain can change +over + + align:start position:0% +over + + + align:start position:0% +over +large areas of tissue can change its + + align:start position:0% +large areas of tissue can change its + + + align:start position:0% +large areas of tissue can change its +state behave differently + + align:start position:0% + + + + align:start position:0% + +but the other kind of correlation + + align:start position:0% +but the other kind of correlation + + + align:start position:0% +but the other kind of correlation +that you see much more often is to + + align:start position:0% +that you see much more often is to + + + align:start position:0% +that you see much more often is to +correlate the activity of neurons in + + align:start position:0% +correlate the activity of neurons in + + + align:start position:0% +correlate the activity of neurons in +specific areas of the brain with + + align:start position:0% +specific areas of the brain with + + + align:start position:0% +specific areas of the brain with +behavior + + align:start position:0% +behavior + + + align:start position:0% +behavior +so for example if you're looking at the + + align:start position:0% +so for example if you're looking at the + + + align:start position:0% +so for example if you're looking at the +movement of the wrist and you record + + align:start position:0% +movement of the wrist and you record + + + align:start position:0% +movement of the wrist and you record +you've say train the monkey to make + + align:start position:0% +you've say train the monkey to make + + + align:start position:0% +you've say train the monkey to make +simple wrist flexion and extension + + align:start position:0% +simple wrist flexion and extension + + + align:start position:0% +simple wrist flexion and extension +you can find neurons for example in the + + align:start position:0% +you can find neurons for example in the + + + align:start position:0% +you can find neurons for example in the +motor cortex + + align:start position:0% +motor cortex + + + align:start position:0% +motor cortex +that specifically fire with precise in a + + align:start position:0% +that specifically fire with precise in a + + + align:start position:0% +that specifically fire with precise in a +precise temporal correlation + + align:start position:0% +precise temporal correlation + + + align:start position:0% +precise temporal correlation +with that movement + + align:start position:0% +with that movement + + + align:start position:0% +with that movement +okay + + align:start position:0% +okay + + + align:start position:0% +okay +certain neurons will fire when the + + align:start position:0% +certain neurons will fire when the + + + align:start position:0% +certain neurons will fire when the +animal is flexing certain neurons will + + align:start position:0% +animal is flexing certain neurons will + + + align:start position:0% +animal is flexing certain neurons will +fire when he's extending + + align:start position:0% +fire when he's extending + + + align:start position:0% +fire when he's extending +okay + + align:start position:0% +okay + + + align:start position:0% +okay +and in fact they find neurons that will + + align:start position:0% +and in fact they find neurons that will + + + align:start position:0% +and in fact they find neurons that will +start to fire before the movement + + align:start position:0% +start to fire before the movement + + + align:start position:0% +start to fire before the movement +okay + + align:start position:0% +okay + + + align:start position:0% +okay +always seem to precede the movement + + align:start position:0% +always seem to precede the movement + + + align:start position:0% +always seem to precede the movement +by a rather precise time interval + + align:start position:0% +by a rather precise time interval + + + align:start position:0% +by a rather precise time interval +there are other neurons especially in + + align:start position:0% +there are other neurons especially in + + + align:start position:0% +there are other neurons especially in +the sensory cortex which will follow the + + align:start position:0% +the sensory cortex which will follow the + + + align:start position:0% +the sensory cortex which will follow the +movement but will fire after the + + align:start position:0% +movement but will fire after the + + + align:start position:0% +movement but will fire after the +movement occurs + + align:start position:0% + + + + align:start position:0% + +so that kind of correlation has also + + align:start position:0% +so that kind of correlation has also + + + align:start position:0% +so that kind of correlation has also +been fascinating to people + + align:start position:0% +been fascinating to people + + + align:start position:0% +been fascinating to people +it never + + align:start position:0% +it never + + + align:start position:0% +it never +looking at the limitations here it never + + align:start position:0% +looking at the limitations here it never + + + align:start position:0% +looking at the limitations here it never +tells you exactly what causes what + + align:start position:0% +tells you exactly what causes what + + + align:start position:0% +tells you exactly what causes what +without other experiments to do that + + align:start position:0% + + + + align:start position:0% + +modern imaging techniques are of a + + align:start position:0% +modern imaging techniques are of a + + + align:start position:0% +modern imaging techniques are of a +similar thing we're looking at + + align:start position:0% +similar thing we're looking at + + + align:start position:0% +similar thing we're looking at +correlations + + align:start position:0% +correlations + + + align:start position:0% +correlations +of what's happening + + align:start position:0% +of what's happening + + + align:start position:0% +of what's happening +not telling us about cause and effect + + align:start position:0% +not telling us about cause and effect + + + align:start position:0% +not telling us about cause and effect +but we do find consistent + + align:start position:0% +but we do find consistent + + + align:start position:0% +but we do find consistent +areas of the brain + + align:start position:0% +areas of the brain + + + align:start position:0% +areas of the brain +that where the tissue oxygenation is + + align:start position:0% +that where the tissue oxygenation is + + + align:start position:0% +that where the tissue oxygenation is +greater the blood flow is greater when + + align:start position:0% +greater the blood flow is greater when + + + align:start position:0% +greater the blood flow is greater when +the person is doing a certain thing or + + align:start position:0% +the person is doing a certain thing or + + + align:start position:0% +the person is doing a certain thing or +sensing a certain thing or + + align:start position:0% +sensing a certain thing or + + + align:start position:0% +sensing a certain thing or +making certain movements + + align:start position:0% + + + + align:start position:0% + +so it's that third goal that we see + + align:start position:0% +so it's that third goal that we see + + + align:start position:0% +so it's that third goal that we see +pursued + + align:start position:0% +pursued + + + align:start position:0% +pursued +in + + align:start position:0% +in + + + align:start position:0% +in +modern imaging techniques + + align:start position:0% +modern imaging techniques + + + align:start position:0% +modern imaging techniques +but it does make of course many + + align:start position:0% +but it does make of course many + + + align:start position:0% +but it does make of course many +suggestions about behavior if you can + + align:start position:0% +suggestions about behavior if you can + + + align:start position:0% +suggestions about behavior if you can +localize + + align:start position:0% +localize + + + align:start position:0% +localize +consistently areas that are + + align:start position:0% +consistently areas that are + + + align:start position:0% +consistently areas that are +have this kind of activation and a + + align:start position:0% +have this kind of activation and a + + + align:start position:0% +have this kind of activation and a +certain behavior then we know we can go + + align:start position:0% +certain behavior then we know we can go + + + align:start position:0% +certain behavior then we know we can go +from there and thinking about how + + align:start position:0% +from there and thinking about how + + + align:start position:0% +from there and thinking about how +different regions are + + align:start position:0% +different regions are + + + align:start position:0% +different regions are +dividing up the task of + + align:start position:0% +dividing up the task of + + + align:start position:0% +dividing up the task of +controlling a certain function + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so + + align:start position:0% +so + + + align:start position:0% +so +what we're going i'll let i'm going to + + align:start position:0% +what we're going i'll let i'm going to + + + align:start position:0% +what we're going i'll let i'm going to +go through a little bit about the modern + + align:start position:0% +go through a little bit about the modern + + + align:start position:0% +go through a little bit about the modern +subsystems approach i think that's was + + align:start position:0% +subsystems approach i think that's was + + + align:start position:0% +subsystems approach i think that's was +the last + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +first of all + + align:start position:0% + + + + align:start position:0% + +the modern synthesis has to take into + + align:start position:0% +the modern synthesis has to take into + + + align:start position:0% +the modern synthesis has to take into +account a number of things for one thing + + align:start position:0% +account a number of things for one thing + + + align:start position:0% +account a number of things for one thing +we know that central nervous system + + align:start position:0% +we know that central nervous system + + + align:start position:0% +we know that central nervous system +ingredients the neurons and the other + + align:start position:0% +ingredients the neurons and the other + + + align:start position:0% +ingredients the neurons and the other +cells involved in the nervous system are + + align:start position:0% +cells involved in the nervous system are + + + align:start position:0% +cells involved in the nervous system are +a lot more complex than + + align:start position:0% +a lot more complex than + + + align:start position:0% +a lot more complex than +reflex notions would indicate + + align:start position:0% + + + + align:start position:0% + +so our circuits the way we draw circuits + + align:start position:0% +so our circuits the way we draw circuits + + + align:start position:0% +so our circuits the way we draw circuits +are + + align:start position:0% +are + + + align:start position:0% +are +pretty limited and what they mean + + align:start position:0% +pretty limited and what they mean + + + align:start position:0% +pretty limited and what they mean +because they don't take into account + + align:start position:0% +because they don't take into account + + + align:start position:0% +because they don't take into account +some of the complexity of neurons + + align:start position:0% + + + + align:start position:0% + +we know that we can localize subsystems + + align:start position:0% +we know that we can localize subsystems + + + align:start position:0% +we know that we can localize subsystems +and we saw that with carl wernicke + + align:start position:0% +and we saw that with carl wernicke + + + align:start position:0% +and we saw that with carl wernicke +localizing areas that were consistently + + align:start position:0% +localizing areas that were consistently + + + align:start position:0% +localizing areas that were consistently +involved in understanding speech and in + + align:start position:0% +involved in understanding speech and in + + + align:start position:0% +involved in understanding speech and in +speaking + + align:start position:0% +speaking + + + align:start position:0% +speaking +so we can + + align:start position:0% + + + + align:start position:0% + +draw information flow diagrams making + + align:start position:0% +draw information flow diagrams making + + + align:start position:0% +draw information flow diagrams making +use of + + align:start position:0% +use of + + + align:start position:0% +use of +their anatomical knowledge + + align:start position:0% +their anatomical knowledge + + + align:start position:0% +their anatomical knowledge +localization of functional knowledge + + align:start position:0% +localization of functional knowledge + + + align:start position:0% +localization of functional knowledge +and what we know about neurons + + align:start position:0% +and what we know about neurons + + + align:start position:0% +and what we know about neurons +we also have to realize that the + + align:start position:0% +we also have to realize that the + + + align:start position:0% +we also have to realize that the +connections aren't always the way the + + align:start position:0% +connections aren't always the way the + + + align:start position:0% +connections aren't always the way the +reflexologists would had depicted them + + align:start position:0% +reflexologists would had depicted them + + + align:start position:0% +reflexologists would had depicted them +from sensory to + + align:start position:0% +from sensory to + + + align:start position:0% +from sensory to +sensation to response + + align:start position:0% +sensation to response + + + align:start position:0% +sensation to response +you get + + align:start position:0% +you get + + + align:start position:0% +you get +feedback from motor to the sensory side + + align:start position:0% +feedback from motor to the sensory side + + + align:start position:0% +feedback from motor to the sensory side +also in fact one of the major + + align:start position:0% +also in fact one of the major + + + align:start position:0% +also in fact one of the major +connections of some these the sensory + + align:start position:0% +connections of some these the sensory + + + align:start position:0% +connections of some these the sensory +cortex + + align:start position:0% + + + + align:start position:0% + +responding to somatic sensation + + align:start position:0% +responding to somatic sensation + + + align:start position:0% +responding to somatic sensation +is to the sensory side of the spinal + + align:start position:0% +is to the sensory side of the spinal + + + align:start position:0% +is to the sensory side of the spinal +cord + + align:start position:0% +cord + + + align:start position:0% +cord +that's a connection that in fact + + align:start position:0% +that's a connection that in fact + + + align:start position:0% +that's a connection that in fact +physiologists haven't even now paid a + + align:start position:0% +physiologists haven't even now paid a + + + align:start position:0% +physiologists haven't even now paid a +whole lot of attention to + + align:start position:0% +whole lot of attention to + + + align:start position:0% +whole lot of attention to +but it's one that professor beatsy in + + align:start position:0% +but it's one that professor beatsy in + + + align:start position:0% +but it's one that professor beatsy in +our department is becoming much more + + align:start position:0% +our department is becoming much more + + + align:start position:0% +our department is becoming much more +interested in + + align:start position:0% + + + + align:start position:0% + +we also have to remember that our + + align:start position:0% +we also have to remember that our + + + align:start position:0% +we also have to remember that our +connections can be excitatory and + + align:start position:0% +connections can be excitatory and + + + align:start position:0% +connections can be excitatory and +inhibitory and there are different types + + align:start position:0% +inhibitory and there are different types + + + align:start position:0% +inhibitory and there are different types +of connections which we'll be talking + + align:start position:0% +of connections which we'll be talking + + + align:start position:0% +of connections which we'll be talking +about in the next lectures + + align:start position:0% +about in the next lectures + + + align:start position:0% +about in the next lectures +we also know that our modulating + + align:start position:0% +we also know that our modulating + + + align:start position:0% +we also know that our modulating +influence + + align:start position:0% +influence + + + align:start position:0% +influence +that are more system-wide + + align:start position:0% +that are more system-wide + + + align:start position:0% +that are more system-wide +their diffuse connections of certain + + align:start position:0% +their diffuse connections of certain + + + align:start position:0% +their diffuse connections of certain +systems in the brain + + align:start position:0% +systems in the brain + + + align:start position:0% +systems in the brain +there's also changes in the chemical + + align:start position:0% +there's also changes in the chemical + + + align:start position:0% +there's also changes in the chemical +environment + + align:start position:0% +environment + + + align:start position:0% +environment +that we know less about + + align:start position:0% +that we know less about + + + align:start position:0% +that we know less about +but the anatomists have told us quite a + + align:start position:0% +but the anatomists have told us quite a + + + align:start position:0% +but the anatomists have told us quite a +bit about some of these diffuse + + align:start position:0% +bit about some of these diffuse + + + align:start position:0% +bit about some of these diffuse +connections connections + + align:start position:0% +connections connections + + + align:start position:0% +connections connections +and finally we have to remember that + + align:start position:0% +and finally we have to remember that + + + align:start position:0% +and finally we have to remember that +nerve cells + + align:start position:0% +nerve cells + + + align:start position:0% +nerve cells +can generate their own activity + + align:start position:0% +can generate their own activity + + + align:start position:0% +can generate their own activity +but that varies a lot depending on the + + align:start position:0% +but that varies a lot depending on the + + + align:start position:0% +but that varies a lot depending on the +type of neuron okay + + align:start position:0% +type of neuron okay + + + align:start position:0% +type of neuron okay +they can be spontaneously active + + align:start position:0% +they can be spontaneously active + + + align:start position:0% +they can be spontaneously active +so what i'm going to do and i'll only do + + align:start position:0% +so what i'm going to do and i'll only do + + + align:start position:0% +so what i'm going to do and i'll only do +a case of reflexes and we'll stop this + + align:start position:0% +a case of reflexes and we'll stop this + + + align:start position:0% +a case of reflexes and we'll stop this +lecture and we'll go back we'll do this + + align:start position:0% +lecture and we'll go back we'll do this + + + align:start position:0% +lecture and we'll go back we'll do this +next time and then we'll start talking + + align:start position:0% +next time and then we'll start talking + + + align:start position:0% +next time and then we'll start talking +about single neurons + + align:start position:0% +about single neurons + + + align:start position:0% +about single neurons +okay + + align:start position:0% +okay + + + align:start position:0% +okay +talk about information flow in the case + + align:start position:0% +talk about information flow in the case + + + align:start position:0% +talk about information flow in the case +of reflexes + + align:start position:0% +of reflexes + + + align:start position:0% +of reflexes +then i'll use simple gating mechanisms + + align:start position:0% +then i'll use simple gating mechanisms + + + align:start position:0% +then i'll use simple gating mechanisms +to explain motivation and intention + + align:start position:0% +to explain motivation and intention + + + align:start position:0% +to explain motivation and intention +and talk a little bit about evolution of + + align:start position:0% +and talk a little bit about evolution of + + + align:start position:0% +and talk a little bit about evolution of +higher control + + align:start position:0% +higher control + + + align:start position:0% +higher control +this would be an information flow + + align:start position:0% +this would be an information flow + + + align:start position:0% +this would be an information flow +diagram of the reflex you draw the input + + align:start position:0% +diagram of the reflex you draw the input + + + align:start position:0% +diagram of the reflex you draw the input +the sensory side + + align:start position:0% +the sensory side + + + align:start position:0% +the sensory side +it comes into + + align:start position:0% +it comes into + + + align:start position:0% +it comes into +a box + + align:start position:0% +a box + + + align:start position:0% +a box +which corresponds to the central nervous + + align:start position:0% +which corresponds to the central nervous + + + align:start position:0% +which corresponds to the central nervous +system and then goes out that would + + align:start position:0% +system and then goes out that would + + + align:start position:0% +system and then goes out that would +correspond to the connections that go + + align:start position:0% +correspond to the connections that go + + + align:start position:0% +correspond to the connections that go +out through motor neurons muscles + + align:start position:0% + + + + align:start position:0% + +we can draw such diagrams + + align:start position:0% +we can draw such diagrams + + + align:start position:0% +we can draw such diagrams +without referring to the anatomy we can + + align:start position:0% +without referring to the anatomy we can + + + align:start position:0% +without referring to the anatomy we can +base it simply on behavioral studies + + align:start position:0% +base it simply on behavioral studies + + + align:start position:0% +base it simply on behavioral studies +and in fact + + align:start position:0% +and in fact + + + align:start position:0% +and in fact +skinner at harvard + + align:start position:0% + + + + align:start position:0% + +very well known behaviorist said + + align:start position:0% +very well known behaviorist said + + + align:start position:0% +very well known behaviorist said +we don't ever really have to open that + + align:start position:0% +we don't ever really have to open that + + + align:start position:0% +we don't ever really have to open that +box + + align:start position:0% +box + + + align:start position:0% +box +because we can study the laws that + + align:start position:0% +because we can study the laws that + + + align:start position:0% +because we can study the laws that +relate the input and the output + + align:start position:0% +relate the input and the output + + + align:start position:0% +relate the input and the output +we can study this sensory conditions we + + align:start position:0% +we can study this sensory conditions we + + + align:start position:0% +we can study this sensory conditions we +can study behavior of the animal and we + + align:start position:0% +can study behavior of the animal and we + + + align:start position:0% +can study behavior of the animal and we +can + + align:start position:0% +can + + + align:start position:0% +can +find the lawful relationships between + + align:start position:0% +find the lawful relationships between + + + align:start position:0% +find the lawful relationships between +these so we don't need the nervous + + align:start position:0% +these so we don't need the nervous + + + align:start position:0% +these so we don't need the nervous +system + + align:start position:0% + + + + align:start position:0% + +there's some famous debates for people + + align:start position:0% +there's some famous debates for people + + + align:start position:0% +there's some famous debates for people +argued with him + + align:start position:0% + + + + align:start position:0% + +and some of those people were here at + + align:start position:0% +and some of those people were here at + + + align:start position:0% +and some of those people were here at +mit + + align:start position:0% +mit + + + align:start position:0% +mit +where the belief was + + align:start position:0% +where the belief was + + + align:start position:0% +where the belief was +no you can't get far enough just the + + align:start position:0% +no you can't get far enough just the + + + align:start position:0% +no you can't get far enough just the +behavioral studies you need to open the + + align:start position:0% +behavioral studies you need to open the + + + align:start position:0% +behavioral studies you need to open the +box + + align:start position:0% +box + + + align:start position:0% +box +and we know that that approach is the + + align:start position:0% +and we know that that approach is the + + + align:start position:0% +and we know that that approach is the +approach that we saw first in + + align:start position:0% +approach that we saw first in + + + align:start position:0% +approach that we saw first in +reflexology and handling with kahal who + + align:start position:0% +reflexology and handling with kahal who + + + align:start position:0% +reflexology and handling with kahal who +finally was able to specify the circuit + + align:start position:0% +finally was able to specify the circuit + + + align:start position:0% +finally was able to specify the circuit +an entire reflex and helped us + + align:start position:0% +an entire reflex and helped us + + + align:start position:0% +an entire reflex and helped us +understand more what's going on and its + + align:start position:0% +understand more what's going on and its + + + align:start position:0% +understand more what's going on and its +complexity + + align:start position:0% +complexity + + + align:start position:0% +complexity +okay so we'll go from there next time \ No newline at end of file diff --git a/jBNVKat3GoQ.txt b/jBNVKat3GoQ.txt new file mode 100644 index 0000000000000000000000000000000000000000..69081f1f0c2626532b6f4f15d45488e3464c585a --- /dev/null +++ b/jBNVKat3GoQ.txt @@ -0,0 +1,371 @@ +align:start position:0% + +here in MIT we usually require students + + align:start position:0% +here in MIT we usually require students + + + align:start position:0% +here in MIT we usually require students +to + + align:start position:0% +to + + + align:start position:0% +to +prepare for one hour class for about + + align:start position:0% +prepare for one hour class for about + + + align:start position:0% +prepare for one hour class for about +like an hour and a half so that's the + + align:start position:0% +like an hour and a half so that's the + + + align:start position:0% +like an hour and a half so that's the +time that we expect students to to give + + align:start position:0% +time that we expect students to to give + + + align:start position:0% +time that we expect students to to give +to this course because it's a 12 uni + + align:start position:0% +to this course because it's a 12 uni + + + align:start position:0% +to this course because it's a 12 uni +course so that's a pretty reasonable + + align:start position:0% +course so that's a pretty reasonable + + + align:start position:0% +course so that's a pretty reasonable +time for them expected and students they + + align:start position:0% +time for them expected and students they + + + align:start position:0% +time for them expected and students they +can usually do it but how can students + + align:start position:0% +can usually do it but how can students + + + align:start position:0% +can usually do it but how can students +they make the best out of those 90 + + align:start position:0% +they make the best out of those 90 + + + align:start position:0% +they make the best out of those 90 +minutes it's it's a a totally different + + align:start position:0% +minutes it's it's a a totally different + + + align:start position:0% +minutes it's it's a a totally different +it's a totally different field that so + + align:start position:0% +it's a totally different field that so + + + align:start position:0% +it's a totally different field that so +far we don't have enough we don't have + + align:start position:0% +far we don't have enough we don't have + + + align:start position:0% +far we don't have enough we don't have +enough resources to know what they're + + align:start position:0% +enough resources to know what they're + + + align:start position:0% +enough resources to know what they're +what what do they exactly do during this + + align:start position:0% +what what do they exactly do during this + + + align:start position:0% +what what do they exactly do during this +90 minutes so I think because too often + + align:start position:0% +90 minutes so I think because too often + + + align:start position:0% +90 minutes so I think because too often +students that would say they would say + + align:start position:0% +students that would say they would say + + + align:start position:0% +students that would say they would say +that I follow every procedures that you + + align:start position:0% +that I follow every procedures that you + + + align:start position:0% +that I follow every procedures that you +recommended but I feel the result is not + + align:start position:0% +recommended but I feel the result is not + + + align:start position:0% +recommended but I feel the result is not +that satisfactory what am I supposed to + + align:start position:0% +that satisfactory what am I supposed to + + + align:start position:0% +that satisfactory what am I supposed to +do more and + + align:start position:0% +do more and + + + align:start position:0% +do more and +in this case we usually provide + + align:start position:0% +in this case we usually provide + + + align:start position:0% +in this case we usually provide +individual sessions so we have the + + align:start position:0% +individual sessions so we have the + + + align:start position:0% +individual sessions so we have the +students come into our our office and + + align:start position:0% +students come into our our office and + + + align:start position:0% +students come into our our office and +kind of tell them that show me how you + + align:start position:0% +kind of tell them that show me how you + + + align:start position:0% +kind of tell them that show me how you +prepare for class and kind observe so I + + align:start position:0% +prepare for class and kind observe so I + + + align:start position:0% +prepare for class and kind observe so I +give you 10 minutes so you do your + + align:start position:0% +give you 10 minutes so you do your + + + align:start position:0% +give you 10 minutes so you do your +preparation here in my office and I + + align:start position:0% +preparation here in my office and I + + + align:start position:0% +preparation here in my office and I +observe and based on those 10 minutes to + + align:start position:0% +observe and based on those 10 minutes to + + + align:start position:0% +observe and based on those 10 minutes to +15 minutes students I give you my + + align:start position:0% +15 minutes students I give you my + + + align:start position:0% +15 minutes students I give you my +feedback what I observe is hey you spend + + align:start position:0% +feedback what I observe is hey you spend + + + align:start position:0% +feedback what I observe is hey you spend +too much on on this and this and you're + + align:start position:0% +too much on on this and this and you're + + + align:start position:0% +too much on on this and this and you're +too silence you you cannot be too silent + + align:start position:0% +too silence you you cannot be too silent + + + align:start position:0% +too silence you you cannot be too silent +when you prepare for classes because in + + align:start position:0% +when you prepare for classes because in + + + align:start position:0% +when you prepare for classes because in +class it's about production production + + align:start position:0% +class it's about production production + + + align:start position:0% +class it's about production production +is very loud so this kind of loudness or + + align:start position:0% +is very loud so this kind of loudness or + + + align:start position:0% +is very loud so this kind of loudness or +or the loud part should be reflected + + align:start position:0% +or the loud part should be reflected + + + align:start position:0% +or the loud part should be reflected +from your + + align:start position:0% +from your + + + align:start position:0% +from your +preparation and from the 10 minutes or + + align:start position:0% +preparation and from the 10 minutes or + + + align:start position:0% +preparation and from the 10 minutes or +15 minutes you're solent for 12 + + align:start position:0% +15 minutes you're solent for 12 + + + align:start position:0% +15 minutes you're solent for 12 +minutes which is not the case in class + + align:start position:0% +minutes which is not the case in class + + + align:start position:0% +minutes which is not the case in class +whenever student is say I do this this + + align:start position:0% +whenever student is say I do this this + + + align:start position:0% +whenever student is say I do this this +this and this you really don't know how + + align:start position:0% +this and this you really don't know how + + + align:start position:0% +this and this you really don't know how +much you can trust them in no way so the + + align:start position:0% +much you can trust them in no way so the + + + align:start position:0% +much you can trust them in no way so the +best way to check is to have them here + + align:start position:0% +best way to check is to have them here + + + align:start position:0% +best way to check is to have them here +and show you how to prepare for the + + align:start position:0% +and show you how to prepare for the + + + align:start position:0% +and show you how to prepare for the +class \ No newline at end of file diff --git a/kEoJ-teErzM.txt b/kEoJ-teErzM.txt new file mode 100644 index 0000000000000000000000000000000000000000..32c516b912fd6ff36264335601412870720ed06d --- /dev/null +++ b/kEoJ-teErzM.txt @@ -0,0 +1,1251 @@ +align:start position:0% + +in this section of the course I'm going + + align:start position:0% +in this section of the course I'm going + + + align:start position:0% +in this section of the course I'm going +to go directly jump to GIS so geographic + + align:start position:0% +to go directly jump to GIS so geographic + + + align:start position:0% +to go directly jump to GIS so geographic +information systems and before going + + align:start position:0% +information systems and before going + + + align:start position:0% +information systems and before going +directly to the code I just wanted to + + align:start position:0% +directly to the code I just wanted to + + + align:start position:0% +directly to the code I just wanted to +make sure that everybody's in the same + + align:start position:0% +make sure that everybody's in the same + + + align:start position:0% +make sure that everybody's in the same +page in some key Concepts so that's why + + align:start position:0% +page in some key Concepts so that's why + + + align:start position:0% +page in some key Concepts so that's why +I'm just going to clarify some of them + + align:start position:0% +I'm just going to clarify some of them + + + align:start position:0% +I'm just going to clarify some of them +um so what you're going going to learn + + align:start position:0% +um so what you're going going to learn + + + align:start position:0% +um so what you're going going to learn +in in this video is to be familiarized + + align:start position:0% +in in this video is to be familiarized + + + align:start position:0% +in in this video is to be familiarized +with Concepts such as uh what are + + align:start position:0% +with Concepts such as uh what are + + + align:start position:0% +with Concepts such as uh what are +victorial maps and what are raster Maps + + align:start position:0% +victorial maps and what are raster Maps + + + align:start position:0% +victorial maps and what are raster Maps +so what are the differences among them + + align:start position:0% +so what are the differences among them + + + align:start position:0% +so what are the differences among them +and where should we use one or the other + + align:start position:0% +and where should we use one or the other + + + align:start position:0% +and where should we use one or the other +uh what is the projection so why do we + + align:start position:0% +uh what is the projection so why do we + + + align:start position:0% +uh what is the projection so why do we +need different projections also what's + + align:start position:0% +need different projections also what's + + + align:start position:0% +need different projections also what's +the concept of resolution and why should + + align:start position:0% +the concept of resolution and why should + + + align:start position:0% +the concept of resolution and why should +we take into account resolution when + + align:start position:0% +we take into account resolution when + + + align:start position:0% +we take into account resolution when +working with maps and also different + + align:start position:0% +working with maps and also different + + + align:start position:0% +working with maps and also different +ways to create Maps so there are mostly + + align:start position:0% +ways to create Maps so there are mostly + + + align:start position:0% +ways to create Maps so there are mostly +two different approaches to create Maps + + align:start position:0% +two different approaches to create Maps + + + align:start position:0% +two different approaches to create Maps +which the first one would be the + + align:start position:0% +which the first one would be the + + + align:start position:0% +which the first one would be the +satellite maps that are created top to + + align:start position:0% +satellite maps that are created top to + + + align:start position:0% +satellite maps that are created top to +bottom and then we have the maps that + + align:start position:0% +bottom and then we have the maps that + + + align:start position:0% +bottom and then we have the maps that +are upscale that they are the other way + + align:start position:0% +are upscale that they are the other way + + + align:start position:0% +are upscale that they are the other way +around so they are created bottom to top + + align:start position:0% +around so they are created bottom to top + + + align:start position:0% +around so they are created bottom to top +so my goal is that then you would be + + align:start position:0% +so my goal is that then you would be + + + align:start position:0% +so my goal is that then you would be +able to apply all these Concepts and + + align:start position:0% +able to apply all these Concepts and + + + align:start position:0% +able to apply all these Concepts and +manage all these Concepts in your R + + align:start position:0% + + + + align:start position:0% + +code okay so here we have the same image + + align:start position:0% +code okay so here we have the same image + + + align:start position:0% +code okay so here we have the same image +represented in the two different Maps so + + align:start position:0% +represented in the two different Maps so + + + align:start position:0% +represented in the two different Maps so +the first one is represented using a + + align:start position:0% +the first one is represented using a + + + align:start position:0% +the first one is represented using a +vectorial map and the second one is + + align:start position:0% +vectorial map and the second one is + + + align:start position:0% +vectorial map and the second one is +represented using raster the main + + align:start position:0% +represented using raster the main + + + align:start position:0% +represented using raster the main +differences is that in vectorial maps we + + align:start position:0% +differences is that in vectorial maps we + + + align:start position:0% +differences is that in vectorial maps we +can have irregular uh polygons but in + + align:start position:0% +can have irregular uh polygons but in + + + align:start position:0% +can have irregular uh polygons but in +the raster Maps we have a grid where all + + align:start position:0% +the raster Maps we have a grid where all + + + align:start position:0% +the raster Maps we have a grid where all +the cells are equally distributed they + + align:start position:0% +the cells are equally distributed they + + + align:start position:0% +the cells are equally distributed they +have the same size and they are in the + + align:start position:0% +have the same size and they are in the + + + align:start position:0% +have the same size and they are in the +same disposition so that might affect + + align:start position:0% +same disposition so that might affect + + + align:start position:0% +same disposition so that might affect +how the different forms are represented + + align:start position:0% +how the different forms are represented + + + align:start position:0% +how the different forms are represented +so in case we are interested in the the + + align:start position:0% +so in case we are interested in the the + + + align:start position:0% +so in case we are interested in the the +shape of the objects maybe we would go + + align:start position:0% +shape of the objects maybe we would go + + + align:start position:0% +shape of the objects maybe we would go +to a vectorial map but if we are + + align:start position:0% +to a vectorial map but if we are + + + align:start position:0% +to a vectorial map but if we are +interested in the content of the map we + + align:start position:0% +interested in the content of the map we + + + align:start position:0% +interested in the content of the map we +would go to raster + + align:start position:0% + + + + align:start position:0% + +representations also there is the + + align:start position:0% +representations also there is the + + + align:start position:0% +representations also there is the +concept of projection uh as we all know + + align:start position:0% +concept of projection uh as we all know + + + align:start position:0% +concept of projection uh as we all know +the Earth is not a flat surface so to + + align:start position:0% +the Earth is not a flat surface so to + + + align:start position:0% +the Earth is not a flat surface so to +overcome this representation in like to + + align:start position:0% +overcome this representation in like to + + + align:start position:0% +overcome this representation in like to +convert this round shape into something + + align:start position:0% +convert this round shape into something + + + align:start position:0% +convert this round shape into something +that's flat uh we have encountered + + align:start position:0% +that's flat uh we have encountered + + + align:start position:0% +that's flat uh we have encountered +several problems so that's why we have + + align:start position:0% +several problems so that's why we have + + + align:start position:0% +several problems so that's why we have +different projections depending on + + align:start position:0% +different projections depending on + + + align:start position:0% +different projections depending on +where we want to focus better on so each + + align:start position:0% +where we want to focus better on so each + + + align:start position:0% +where we want to focus better on so each +representation has its pros and Cones so + + align:start position:0% +representation has its pros and Cones so + + + align:start position:0% +representation has its pros and Cones so +for example if we are more interested in + + align:start position:0% +for example if we are more interested in + + + align:start position:0% +for example if we are more interested in +having accurate shapes in the poles we + + align:start position:0% +having accurate shapes in the poles we + + + align:start position:0% +having accurate shapes in the poles we +would use one projection but if we want + + align:start position:0% +would use one projection but if we want + + + align:start position:0% +would use one projection but if we want +to see kind of accurately the whole glob + + align:start position:0% +to see kind of accurately the whole glob + + + align:start position:0% +to see kind of accurately the whole glob +maybe we choose something else but that + + align:start position:0% +maybe we choose something else but that + + + align:start position:0% +maybe we choose something else but that +has implications in how the shapes look + + align:start position:0% +has implications in how the shapes look + + + align:start position:0% +has implications in how the shapes look +like for example this is the same phase + + align:start position:0% +like for example this is the same phase + + + align:start position:0% +like for example this is the same phase +but how this can be transformed or + + align:start position:0% +but how this can be transformed or + + + align:start position:0% +but how this can be transformed or +deformed depending on how we are + + align:start position:0% +deformed depending on how we are + + + align:start position:0% +deformed depending on how we are +representing it so this is something we + + align:start position:0% +representing it so this is something we + + + align:start position:0% +representing it so this is something we +have to take into account because if we + + align:start position:0% +have to take into account because if we + + + align:start position:0% +have to take into account because if we +want to merge to extract information + + align:start position:0% +want to merge to extract information + + + align:start position:0% +want to merge to extract information +from different Maps they may be in + + align:start position:0% +from different Maps they may be in + + + align:start position:0% +from different Maps they may be in +different projections and how is this + + align:start position:0% +different projections and how is this + + + align:start position:0% +different projections and how is this +affecting us + + align:start position:0% +affecting us + + + align:start position:0% +affecting us +well here you see South America and how + + align:start position:0% +well here you see South America and how + + + align:start position:0% +well here you see South America and how +this South America can be represented on + + align:start position:0% +this South America can be represented on + + + align:start position:0% +this South America can be represented on +how it shape can change depending on the + + align:start position:0% +how it shape can change depending on the + + + align:start position:0% +how it shape can change depending on the +projection we are using so before moving + + align:start position:0% +projection we are using so before moving + + + align:start position:0% +projection we are using so before moving +on in in maps we have to make sure that + + align:start position:0% +on in in maps we have to make sure that + + + align:start position:0% +on in in maps we have to make sure that +the projection we are using is accurate + + align:start position:0% +the projection we are using is accurate + + + align:start position:0% +the projection we are using is accurate +to the piece of the earth that we want + + align:start position:0% +to the piece of the earth that we want + + + align:start position:0% +to the piece of the earth that we want +to represent or that we want to work on + + align:start position:0% +to represent or that we want to work on + + + align:start position:0% +to represent or that we want to work on +what's the scale we are going to work on + + align:start position:0% +what's the scale we are going to work on + + + align:start position:0% +what's the scale we are going to work on +if we're going to work in a regional + + align:start position:0% +if we're going to work in a regional + + + align:start position:0% +if we're going to work in a regional +part or if we're going to work in a + + align:start position:0% +part or if we're going to work in a + + + align:start position:0% +part or if we're going to work in a +global scale and also make sure that all + + align:start position:0% +global scale and also make sure that all + + + align:start position:0% +global scale and also make sure that all +the maps are in the same projection so + + align:start position:0% +the maps are in the same projection so + + + align:start position:0% +the maps are in the same projection so +we don't have problems as in the + + align:start position:0% + + + + align:start position:0% + +image then we have the resolution + + align:start position:0% +image then we have the resolution + + + align:start position:0% +image then we have the resolution +concept this is a a picture but a + + align:start position:0% +concept this is a a picture but a + + + align:start position:0% +concept this is a a picture but a +picture would be a good proxy of a a + + align:start position:0% +picture would be a good proxy of a a + + + align:start position:0% +picture would be a good proxy of a a +raster map the end they are built the + + align:start position:0% +raster map the end they are built the + + + align:start position:0% +raster map the end they are built the +same + + align:start position:0% +same + + + align:start position:0% +same +um so here we have the same image um and + + align:start position:0% +um so here we have the same image um and + + + align:start position:0% +um so here we have the same image um and +and the main difference is that the + + align:start position:0% +and the main difference is that the + + + align:start position:0% +and the main difference is that the +square size is completely different so + + align:start position:0% +square size is completely different so + + + align:start position:0% +square size is completely different so +the first one the one is more in the + + align:start position:0% +the first one the one is more in the + + + align:start position:0% +the first one the one is more in the +left um it doesn't have that much of a + + align:start position:0% +left um it doesn't have that much of a + + + align:start position:0% +left um it doesn't have that much of a +detail and the second one is very + + align:start position:0% +detail and the second one is very + + + align:start position:0% +detail and the second one is very +detailed one would think that is always + + align:start position:0% +detailed one would think that is always + + + align:start position:0% +detailed one would think that is always +better to go to more detailed resolution + + align:start position:0% +better to go to more detailed resolution + + + align:start position:0% +better to go to more detailed resolution +but this has some drawbacks which is + + align:start position:0% +but this has some drawbacks which is + + + align:start position:0% +but this has some drawbacks which is +that they are way more heavy so + + align:start position:0% +that they are way more heavy so + + + align:start position:0% +that they are way more heavy so +depending on the capacity your computer + + align:start position:0% +depending on the capacity your computer + + + align:start position:0% +depending on the capacity your computer +has or depending on how good is your + + align:start position:0% +has or depending on how good is your + + + align:start position:0% +has or depending on how good is your +internet connection you might go to one + + align:start position:0% +internet connection you might go to one + + + align:start position:0% +internet connection you might go to one +or the other um just as a um as a + + align:start position:0% +or the other um just as a um as a + + + align:start position:0% +or the other um just as a um as a +reminder that it sometimes even if you + + align:start position:0% +reminder that it sometimes even if you + + + align:start position:0% +reminder that it sometimes even if you +are increasing the resolution maybe + + align:start position:0% +are increasing the resolution maybe + + + align:start position:0% +are increasing the resolution maybe +that's not going to help us to have more + + align:start position:0% +that's not going to help us to have more + + + align:start position:0% +that's not going to help us to have more +accurate calculations just because the + + align:start position:0% +accurate calculations just because the + + + align:start position:0% +accurate calculations just because the +quality of the map uh was initially not + + align:start position:0% +quality of the map uh was initially not + + + align:start position:0% +quality of the map uh was initially not +the the purest and was created in a + + align:start position:0% +the the purest and was created in a + + + align:start position:0% +the the purest and was created in a +corser resolution so even if we come to + + align:start position:0% +corser resolution so even if we come to + + + align:start position:0% +corser resolution so even if we come to +if we can transform a corser resolution + + align:start position:0% +if we can transform a corser resolution + + + align:start position:0% +if we can transform a corser resolution +to a more fine scale um we are not + + align:start position:0% +to a more fine scale um we are not + + + align:start position:0% +to a more fine scale um we are not +creating new + + align:start position:0% + + + + align:start position:0% + +information so this is the top bottom + + align:start position:0% +information so this is the top bottom + + + align:start position:0% +information so this is the top bottom +approach of creating Maps um we know + + align:start position:0% +approach of creating Maps um we know + + + align:start position:0% +approach of creating Maps um we know +that we have satellites going around + + align:start position:0% +that we have satellites going around + + + align:start position:0% +that we have satellites going around +above our heads so they use as a big + + align:start position:0% +above our heads so they use as a big + + + align:start position:0% +above our heads so they use as a big +camera let's say so they have different + + align:start position:0% +camera let's say so they have different + + + align:start position:0% +camera let's say so they have different +sensors they have different lenses so + + align:start position:0% +sensors they have different lenses so + + + align:start position:0% +sensors they have different lenses so +they are taking kind of pictures or + + align:start position:0% +they are taking kind of pictures or + + + align:start position:0% +they are taking kind of pictures or +representations of the surface of the + + align:start position:0% +representations of the surface of the + + + align:start position:0% +representations of the surface of the +Earth so they send different web lengths + + align:start position:0% +Earth so they send different web lengths + + + align:start position:0% +Earth so they send different web lengths +and then they get some bounced back and + + align:start position:0% +and then they get some bounced back and + + + align:start position:0% +and then they get some bounced back and +then they read the signal of that and + + align:start position:0% +then they read the signal of that and + + + align:start position:0% +then they read the signal of that and +based on those signals they apply some + + align:start position:0% +based on those signals they apply some + + + align:start position:0% +based on those signals they apply some +corrections sometimes and that's how + + align:start position:0% +corrections sometimes and that's how + + + align:start position:0% +corrections sometimes and that's how +they create satellite images but then + + align:start position:0% +they create satellite images but then + + + align:start position:0% +they create satellite images but then +another way to create Maps sometimes + + align:start position:0% +another way to create Maps sometimes + + + align:start position:0% +another way to create Maps sometimes +when we don't have a signal from a + + align:start position:0% +when we don't have a signal from a + + + align:start position:0% +when we don't have a signal from a +satellite would be the upscaling + + align:start position:0% +satellite would be the upscaling + + + align:start position:0% +satellite would be the upscaling +approach here in the first map uh we + + align:start position:0% +approach here in the first map uh we + + + align:start position:0% +approach here in the first map uh we +have different dots uh this is taken + + align:start position:0% +have different dots uh this is taken + + + align:start position:0% +have different dots uh this is taken +from a paper uh do it all um + + align:start position:0% +from a paper uh do it all um + + + align:start position:0% +from a paper uh do it all um +2020 um it's just an example of an + + align:start position:0% +2020 um it's just an example of an + + + align:start position:0% +2020 um it's just an example of an +upscaled map where they had real data so + + align:start position:0% +upscaled map where they had real data so + + + align:start position:0% +upscaled map where they had real data so +each point is representing a real point + + align:start position:0% +each point is representing a real point + + + align:start position:0% +each point is representing a real point +where some field data has been taken + + align:start position:0% +where some field data has been taken + + + align:start position:0% +where some field data has been taken +then based on this real information um a + + align:start position:0% +then based on this real information um a + + + align:start position:0% +then based on this real information um a +model is created using some + + align:start position:0% +model is created using some + + + align:start position:0% +model is created using some +environmental drivers so drivers and a + + align:start position:0% +environmental drivers so drivers and a + + + align:start position:0% +environmental drivers so drivers and a +model is created and with this model + + align:start position:0% +model is created and with this model + + + align:start position:0% +model is created and with this model +then we can empty the spaces that are in + + align:start position:0% +then we can empty the spaces that are in + + + align:start position:0% +then we can empty the spaces that are in +between different the different points + + align:start position:0% +between different the different points + + + align:start position:0% +between different the different points +based on an upscaling using that map so + + align:start position:0% +based on an upscaling using that map so + + + align:start position:0% +based on an upscaling using that map so +this is how we can obtain maps from a + + align:start position:0% +this is how we can obtain maps from a + + + align:start position:0% +this is how we can obtain maps from a +bottom top approach + + align:start position:0% +bottom top approach + + + align:start position:0% +bottom top approach +and also here just some resources you + + align:start position:0% +and also here just some resources you + + + align:start position:0% +and also here just some resources you +can find um raster Maps uh the first one + + align:start position:0% +can find um raster Maps uh the first one + + + align:start position:0% +can find um raster Maps uh the first one +is the world cream world caim where you + + align:start position:0% +is the world cream world caim where you + + + align:start position:0% +is the world cream world caim where you +can find environmental uh variables such + + align:start position:0% +can find environmental uh variables such + + + align:start position:0% +can find environmental uh variables such +as what related to climate precipitation + + align:start position:0% +as what related to climate precipitation + + + align:start position:0% +as what related to climate precipitation +temperature and so forth and then if you + + align:start position:0% +temperature and so forth and then if you + + + align:start position:0% +temperature and so forth and then if you +are interested in obtaining information + + align:start position:0% +are interested in obtaining information + + + align:start position:0% +are interested in obtaining information +from soils you might go to soil GDs + + align:start position:0% +from soils you might go to soil GDs + + + align:start position:0% +from soils you might go to soil GDs +where they have a lot of physical and + + align:start position:0% +where they have a lot of physical and + + + align:start position:0% +where they have a lot of physical and +chemical properties uh of different + + align:start position:0% + + + + align:start position:0% + +soils e \ No newline at end of file diff --git a/kigLhcTm_gg.txt b/kigLhcTm_gg.txt new file mode 100644 index 0000000000000000000000000000000000000000..df18478d088db3092e41a686b6202af0ab2bce2c --- /dev/null +++ b/kigLhcTm_gg.txt @@ -0,0 +1,16355 @@ +align:start position:0% + +uh we're talking about + + align:start position:0% +uh we're talking about + + + align:start position:0% +uh we're talking about +photogrammetry and in particular + + align:start position:0% +photogrammetry and in particular + + + align:start position:0% +photogrammetry and in particular +absolute orientation and we're drilling + + align:start position:0% +absolute orientation and we're drilling + + + align:start position:0% +absolute orientation and we're drilling +down into uh details + + align:start position:0% +down into uh details + + + align:start position:0% +down into uh details +uh more details for this one than we + + align:start position:0% +uh more details for this one than we + + + align:start position:0% +uh more details for this one than we +will for the other aspects of + + align:start position:0% +will for the other aspects of + + + align:start position:0% +will for the other aspects of +photogrammetry + + align:start position:0% +photogrammetry + + + align:start position:0% +photogrammetry +because a lot of it's + + align:start position:0% +because a lot of it's + + + align:start position:0% +because a lot of it's +going to be based on what we're doing + + align:start position:0% +going to be based on what we're doing + + + align:start position:0% +going to be based on what we're doing +here + + align:start position:0% +here + + + align:start position:0% +here +and we found that rotation is the part + + align:start position:0% +and we found that rotation is the part + + + align:start position:0% +and we found that rotation is the part +that's awkward to handle so we talked + + align:start position:0% +that's awkward to handle so we talked + + + align:start position:0% +that's awkward to handle so we talked +about different ways of representing + + align:start position:0% +about different ways of representing + + + align:start position:0% +about different ways of representing +rotations + + align:start position:0% +rotations + + + align:start position:0% +rotations +and we picked uh unit quaternions + + align:start position:0% +and we picked uh unit quaternions + + + align:start position:0% +and we picked uh unit quaternions +and a + + align:start position:0% +and a + + + align:start position:0% +and a +major reason for that is that um + + align:start position:0% +major reason for that is that um + + + align:start position:0% +major reason for that is that um +given all of the advantages we discussed + + align:start position:0% +given all of the advantages we discussed + + + align:start position:0% +given all of the advantages we discussed +before the the big thing for us is we + + align:start position:0% +before the the big thing for us is we + + + align:start position:0% +before the the big thing for us is we +can get a closed form solution to the + + align:start position:0% +can get a closed form solution to the + + + align:start position:0% +can get a closed form solution to the +least worse problem so in some sense we + + align:start position:0% +least worse problem so in some sense we + + + align:start position:0% +least worse problem so in some sense we +have a + + align:start position:0% +have a + + + align:start position:0% +have a +objective way of getting a quote best + + align:start position:0% +objective way of getting a quote best + + + align:start position:0% +objective way of getting a quote best +fit answer + + align:start position:0% +fit answer + + + align:start position:0% +fit answer +which is more difficult with the other + + align:start position:0% +which is more difficult with the other + + + align:start position:0% +which is more difficult with the other +notations + + align:start position:0% + + + + align:start position:0% + +then we talked about + + align:start position:0% +then we talked about + + + align:start position:0% +then we talked about +how to manipulate these things there are + + align:start position:0% +how to manipulate these things there are + + + align:start position:0% +how to manipulate these things there are +two + + align:start position:0% +two + + + align:start position:0% +two +operations we're particularly interested + + align:start position:0% +operations we're particularly interested + + + align:start position:0% +operations we're particularly interested +in the one is + + align:start position:0% +in the one is + + + align:start position:0% +in the one is +composition of rotations if you do + + align:start position:0% +composition of rotations if you do + + + align:start position:0% +composition of rotations if you do +successive rotations what happens + + align:start position:0% +successive rotations what happens + + + align:start position:0% +successive rotations what happens +and the other one is + + align:start position:0% +and the other one is + + + align:start position:0% +and the other one is +rotating a vector so composition of + + align:start position:0% +rotating a vector so composition of + + + align:start position:0% +rotating a vector so composition of +rotations + + align:start position:0% +rotations + + + align:start position:0% +rotations +is just multiplication + + align:start position:0% +is just multiplication + + + align:start position:0% +is just multiplication +and we can represent it in various ways + + align:start position:0% +and we can represent it in various ways + + + align:start position:0% +and we can represent it in various ways +uh for those of us who grew up with + + align:start position:0% +uh for those of us who grew up with + + + align:start position:0% +uh for those of us who grew up with +vectors maybe + + align:start position:0% +vectors maybe + + + align:start position:0% +vectors maybe +mapping it into scalars and vectors is + + align:start position:0% +mapping it into scalars and vectors is + + + align:start position:0% +mapping it into scalars and vectors is +the most intuitive + + align:start position:0% +the most intuitive + + + align:start position:0% +the most intuitive +so we have this formula + + align:start position:0% +so we have this formula + + + align:start position:0% +so we have this formula +and it's + + align:start position:0% +and it's + + + align:start position:0% +and it's +actually quite efficient in terms of + + align:start position:0% +actually quite efficient in terms of + + + align:start position:0% +actually quite efficient in terms of +composition of rotations + + align:start position:0% +composition of rotations + + + align:start position:0% +composition of rotations +a lot in terms of computation it's a lot + + align:start position:0% +a lot in terms of computation it's a lot + + + align:start position:0% +a lot in terms of computation it's a lot +less + + align:start position:0% +less + + + align:start position:0% +less +work than multiplying two orthonormal + + align:start position:0% +work than multiplying two orthonormal + + + align:start position:0% +work than multiplying two orthonormal +three by three matrices + + align:start position:0% +three by three matrices + + + align:start position:0% +three by three matrices +but + + align:start position:0% +but + + + align:start position:0% +but +for much of what we do what's more + + align:start position:0% +for much of what we do what's more + + + align:start position:0% +for much of what we do what's more +important is the other operation which + + align:start position:0% +important is the other operation which + + + align:start position:0% +important is the other operation which +is + + align:start position:0% + + + + align:start position:0% + +a rotation of a vector and so + + align:start position:0% +a rotation of a vector and so + + + align:start position:0% +a rotation of a vector and so +for that + + align:start position:0% +for that + + + align:start position:0% +for that +uh we have that uh formula where we're + + align:start position:0% +uh we have that uh formula where we're + + + align:start position:0% +uh we have that uh formula where we're +you know rotating in four space using q + + align:start position:0% +you know rotating in four space using q + + + align:start position:0% +you know rotating in four space using q +and then we're kind of unrotating using + + align:start position:0% +and then we're kind of unrotating using + + + align:start position:0% +and then we're kind of unrotating using +q conjugate and somehow we end up back + + align:start position:0% +q conjugate and somehow we end up back + + + align:start position:0% +q conjugate and somehow we end up back +in a real three-dimensional world + + align:start position:0% +in a real three-dimensional world + + + align:start position:0% +in a real three-dimensional world +and for that again if we want to just + + align:start position:0% +and for that again if we want to just + + + align:start position:0% +and for that again if we want to just +think about vectors + + align:start position:0% +think about vectors + + + align:start position:0% +think about vectors +we can + + align:start position:0% +we can + + + align:start position:0% +we can +one way we can write it is + + align:start position:0% + + + + align:start position:0% + +so we don't you know if we don't want to + + align:start position:0% +so we don't you know if we don't want to + + + align:start position:0% +so we don't you know if we don't want to +think too much about operations in the + + align:start position:0% +think too much about operations in the + + + align:start position:0% +think too much about operations in the +quaternion world world we can just do + + align:start position:0% +quaternion world world we can just do + + + align:start position:0% +quaternion world world we can just do +this + + align:start position:0% +this + + + align:start position:0% +this +operation directly using vectors and + + align:start position:0% +operation directly using vectors and + + + align:start position:0% +operation directly using vectors and +scalars and + + align:start position:0% +scalars and + + + align:start position:0% +scalars and +this one we have a disadvantage it takes + + align:start position:0% +this one we have a disadvantage it takes + + + align:start position:0% +this one we have a disadvantage it takes +somewhat more arithmetic operations than + + align:start position:0% +somewhat more arithmetic operations than + + + align:start position:0% +somewhat more arithmetic operations than +multiplying a three by three matrix by a + + align:start position:0% +multiplying a three by three matrix by a + + + align:start position:0% +multiplying a three by three matrix by a +vector + + align:start position:0% +vector + + + align:start position:0% +vector +although we saw that the ways of + + align:start position:0% +although we saw that the ways of + + + align:start position:0% +although we saw that the ways of +rewriting this where we reuse the q + + align:start position:0% +rewriting this where we reuse the q + + + align:start position:0% +rewriting this where we reuse the q +cross r + + align:start position:0% +cross r + + + align:start position:0% +cross r +that reduces the number of operations + + align:start position:0% +that reduces the number of operations + + + align:start position:0% +that reduces the number of operations +somewhat + + align:start position:0% +somewhat + + + align:start position:0% +somewhat +and then + + align:start position:0% +and then + + + align:start position:0% +and then +we need to connect this to other + + align:start position:0% +we need to connect this to other + + + align:start position:0% +we need to connect this to other +notations so + + align:start position:0% +notations so + + + align:start position:0% +notations so +we for example + + align:start position:0% + + + + align:start position:0% + +want to relate it to + + align:start position:0% +want to relate it to + + + align:start position:0% +want to relate it to +axes and angle notation + + align:start position:0% +axes and angle notation + + + align:start position:0% +axes and angle notation +and there we have the formula of + + align:start position:0% +and there we have the formula of + + + align:start position:0% +and there we have the formula of +rodriguez + + align:start position:0% + + + + align:start position:0% + +where omega hat is the unit vector in + + align:start position:0% +where omega hat is the unit vector in + + + align:start position:0% +where omega hat is the unit vector in +the direction of the axis + + align:start position:0% +the direction of the axis + + + align:start position:0% +the direction of the axis +and so that gives us + + align:start position:0% +and so that gives us + + + align:start position:0% +and so that gives us +one conversion that we want + + align:start position:0% + + + + align:start position:0% + +uh so uh we can use that to + + align:start position:0% +uh so uh we can use that to + + + align:start position:0% +uh so uh we can use that to +um + + align:start position:0% +um + + + align:start position:0% +um +q dot uh + + align:start position:0% +q dot uh + + + align:start position:0% +q dot uh +sorry about the handwriting yeah + + align:start position:0% +sorry about the handwriting yeah + + + align:start position:0% +sorry about the handwriting yeah +okay um + + align:start position:0% +okay um + + + align:start position:0% +okay um +and when we identify these two formulas + + align:start position:0% +and when we identify these two formulas + + + align:start position:0% +and when we identify these two formulas +uh we find that actually q is cos omega + + align:start position:0% +uh we find that actually q is cos omega + + + align:start position:0% +uh we find that actually q is cos omega +over two + + align:start position:0% +over two + + + align:start position:0% +over two +and omega hat is um + + align:start position:0% +and omega hat is um + + + align:start position:0% +and omega hat is um +uh + + align:start position:0% +uh + + + align:start position:0% +uh +well let's see other way around q + + align:start position:0% +well let's see other way around q + + + align:start position:0% +well let's see other way around q +vector is uh omega hat + + align:start position:0% +vector is uh omega hat + + + align:start position:0% +vector is uh omega hat +sine theta over two oh let me make that + + align:start position:0% +sine theta over two oh let me make that + + + align:start position:0% +sine theta over two oh let me make that +theta sorry + + align:start position:0% + + + + align:start position:0% + +okay so our + + align:start position:0% + + + + align:start position:0% + +quaternion for rotation looks like that + + align:start position:0% +quaternion for rotation looks like that + + + align:start position:0% +quaternion for rotation looks like that +and so we can right away read off the + + align:start position:0% +and so we can right away read off the + + + align:start position:0% +and so we can right away read off the +axis it's going to be parallel to the + + align:start position:0% +axis it's going to be parallel to the + + + align:start position:0% +axis it's going to be parallel to the +vector part + + align:start position:0% +vector part + + + align:start position:0% +vector part +and + + align:start position:0% +and + + + align:start position:0% +and +if we want to we can read off the angle + + align:start position:0% +if we want to we can read off the angle + + + align:start position:0% +if we want to we can read off the angle +by using a tan on the ratio of the + + align:start position:0% +by using a tan on the ratio of the + + + align:start position:0% +by using a tan on the ratio of the +real part and the magnitude of the + + align:start position:0% +real part and the magnitude of the + + + align:start position:0% +real part and the magnitude of the +imaginary part so that + + align:start position:0% +imaginary part so that + + + align:start position:0% +imaginary part so that +is one way of converting between two of + + align:start position:0% +is one way of converting between two of + + + align:start position:0% +is one way of converting between two of +these different forms now we had eight + + align:start position:0% +these different forms now we had eight + + + align:start position:0% +these different forms now we had eight +so + + align:start position:0% +so + + + align:start position:0% +so +we don't want to go through all uh eight + + align:start position:0% +we don't want to go through all uh eight + + + align:start position:0% +we don't want to go through all uh eight +of them + + align:start position:0% +of them + + + align:start position:0% +of them +but the other one that's important for + + align:start position:0% +but the other one that's important for + + + align:start position:0% +but the other one that's important for +us since we live in a world where + + align:start position:0% +us since we live in a world where + + + align:start position:0% +us since we live in a world where +you know + + align:start position:0% +you know + + + align:start position:0% +you know +orthonormal matrices rule we need to be + + align:start position:0% +orthonormal matrices rule we need to be + + + align:start position:0% +orthonormal matrices rule we need to be +able to convert back and forth between + + align:start position:0% +able to convert back and forth between + + + align:start position:0% +able to convert back and forth between +those + + align:start position:0% +those + + + align:start position:0% +those +and so + + align:start position:0% +and so + + + align:start position:0% +and so +if we expand + + align:start position:0% +if we expand + + + align:start position:0% +if we expand +that formula using that isomorphism with + + align:start position:0% +that formula using that isomorphism with + + + align:start position:0% +that formula using that isomorphism with +four by four + + align:start position:0% + + + + align:start position:0% + +orthogonal matrices + + align:start position:0% + + + + align:start position:0% + +then we got that and we expanded that + + align:start position:0% +then we got that and we expanded that + + + align:start position:0% +then we got that and we expanded that +out and + + align:start position:0% + + + + align:start position:0% + +well + + align:start position:0% + + + + align:start position:0% + +and when we look at that matrix + + align:start position:0% +and when we look at that matrix + + + align:start position:0% +and when we look at that matrix +we find that + + align:start position:0% +we find that + + + align:start position:0% +we find that +it has + + align:start position:0% + + + + align:start position:0% + +skew symmetric parts and symmetric parts + + align:start position:0% + + + + align:start position:0% + +and we can use that + + align:start position:0% +and we can use that + + + align:start position:0% +and we can use that +to help us in the conversion from one + + align:start position:0% +to help us in the conversion from one + + + align:start position:0% +to help us in the conversion from one +form to the other so first of all if + + align:start position:0% +form to the other so first of all if + + + align:start position:0% +form to the other so first of all if +we're given the quaternion + + align:start position:0% +we're given the quaternion + + + align:start position:0% +we're given the quaternion +this allows us to compute the + + align:start position:0% + + + + align:start position:0% + +orthonormal matrix very easily + + align:start position:0% + + + + align:start position:0% + +so in this transformation it's four by + + align:start position:0% +so in this transformation it's four by + + + align:start position:0% +so in this transformation it's four by +four + + align:start position:0% +four + + + align:start position:0% +four +but we don't care about the first row in + + align:start position:0% +but we don't care about the first row in + + + align:start position:0% +but we don't care about the first row in +the first column because that is a + + align:start position:0% +the first column because that is a + + + align:start position:0% +the first column because that is a +special quaternion that represents a + + align:start position:0% +special quaternion that represents a + + + align:start position:0% +special quaternion that represents a +vector + + align:start position:0% +vector + + + align:start position:0% +vector +where the first uh with scalar part is + + align:start position:0% +where the first uh with scalar part is + + + align:start position:0% +where the first uh with scalar part is +zero so all this uh that all the first + + align:start position:0% +zero so all this uh that all the first + + + align:start position:0% +zero so all this uh that all the first +column and the first row tell us + + align:start position:0% +column and the first row tell us + + + align:start position:0% +column and the first row tell us +is that if we have a special + + align:start position:0% +is that if we have a special + + + align:start position:0% +is that if we have a special +a real quaternion no a completely + + align:start position:0% +a real quaternion no a completely + + + align:start position:0% +a real quaternion no a completely +imaginary quaternion then when we + + align:start position:0% +imaginary quaternion then when we + + + align:start position:0% +imaginary quaternion then when we +perform this transformation we get back + + align:start position:0% +perform this transformation we get back + + + align:start position:0% +perform this transformation we get back +one of those so we're back in in the + + align:start position:0% +one of those so we're back in in the + + + align:start position:0% +one of those so we're back in in the +world of vectors + + align:start position:0% +world of vectors + + + align:start position:0% +world of vectors +um so that's the one-way conversion the + + align:start position:0% +um so that's the one-way conversion the + + + align:start position:0% +um so that's the one-way conversion the +other way + + align:start position:0% +other way + + + align:start position:0% +other way +is a little bit less obvious + + align:start position:0% +is a little bit less obvious + + + align:start position:0% +is a little bit less obvious +partly because + + align:start position:0% +partly because + + + align:start position:0% +partly because +we're going to have a three by three + + align:start position:0% +we're going to have a three by three + + + align:start position:0% +we're going to have a three by three +matrix so we have nine numbers + + align:start position:0% +matrix so we have nine numbers + + + align:start position:0% +matrix so we have nine numbers +and our answer only has three degrees of + + align:start position:0% +and our answer only has three degrees of + + + align:start position:0% +and our answer only has three degrees of +freedom + + align:start position:0% +freedom + + + align:start position:0% +freedom +we only + + align:start position:0% +we only + + + align:start position:0% +we only +want the axis and the angle and so + + align:start position:0% +want the axis and the angle and so + + + align:start position:0% +want the axis and the angle and so +you've done some of this but one part we + + align:start position:0% +you've done some of this but one part we + + + align:start position:0% +you've done some of this but one part we +can do is to look at the trace of of + + align:start position:0% +can do is to look at the trace of of + + + align:start position:0% +can do is to look at the trace of of +that matrix that three by three sub + + align:start position:0% +that matrix that three by three sub + + + align:start position:0% +that matrix that three by three sub +matrix + + align:start position:0% +matrix + + + align:start position:0% +matrix +and + + align:start position:0% + + + + align:start position:0% + +i think we end up with something like + + align:start position:0% +i think we end up with something like + + + align:start position:0% +i think we end up with something like +three q squared minus + + align:start position:0% + + + + align:start position:0% + +um so it's just running down the + + align:start position:0% +um so it's just running down the + + + align:start position:0% +um so it's just running down the +diagonal + + align:start position:0% +diagonal + + + align:start position:0% +diagonal +and um + + align:start position:0% +and um + + + align:start position:0% +and um +of course q0 + + align:start position:0% +of course q0 + + + align:start position:0% +of course q0 +we said over there was cosine of half + + align:start position:0% +we said over there was cosine of half + + + align:start position:0% +we said over there was cosine of half +the angle + + align:start position:0% + + + + align:start position:0% + +and then this part each of these is + + align:start position:0% +and then this part each of these is + + + align:start position:0% +and then this part each of these is +proportional to + + align:start position:0% +proportional to + + + align:start position:0% +proportional to +sine of half the angle but n is the unit + + align:start position:0% +sine of half the angle but n is the unit + + + align:start position:0% +sine of half the angle but n is the unit +vector so if we take the square of these + + align:start position:0% +vector so if we take the square of these + + + align:start position:0% +vector so if we take the square of these +we should get sine squared theta over + + align:start position:0% +we should get sine squared theta over + + + align:start position:0% +we should get sine squared theta over +two + + align:start position:0% +two + + + align:start position:0% +two +so uh is equal to that + + align:start position:0% +so uh is equal to that + + + align:start position:0% +so uh is equal to that +and um then we can manipulate this + + align:start position:0% +and um then we can manipulate this + + + align:start position:0% +and um then we can manipulate this +various ways like we could add uh cos + + align:start position:0% +various ways like we could add uh cos + + + align:start position:0% +various ways like we could add uh cos +squared theta over two plus sine squared + + align:start position:0% +squared theta over two plus sine squared + + + align:start position:0% +squared theta over two plus sine squared +theta over two equals one + + align:start position:0% +theta over two equals one + + + align:start position:0% +theta over two equals one +in order to get rid of that uh + + align:start position:0% + + + + align:start position:0% + +that sine squared theta + + align:start position:0% +that sine squared theta + + + align:start position:0% +that sine squared theta +so we can add that in without changing + + align:start position:0% +so we can add that in without changing + + + align:start position:0% +so we can add that in without changing +anything or we can subtract it + + align:start position:0% +anything or we can subtract it + + + align:start position:0% +anything or we can subtract it +so if we subtract it + + align:start position:0% + + + + align:start position:0% + +and we get that submit that thing that's + + align:start position:0% +and we get that submit that thing that's + + + align:start position:0% +and we get that submit that thing that's +more symmetrical in cosine and sine and + + align:start position:0% +more symmetrical in cosine and sine and + + + align:start position:0% +more symmetrical in cosine and sine and +of course that's the + + align:start position:0% +of course that's the + + + align:start position:0% +of course that's the +double angle formula so that's two + + align:start position:0% +double angle formula so that's two + + + align:start position:0% +double angle formula so that's two +cosine of theta oh we need the minus 1. + + align:start position:0% +cosine of theta oh we need the minus 1. + + + align:start position:0% +cosine of theta oh we need the minus 1. +and from that we can solve for cosine of + + align:start position:0% +and from that we can solve for cosine of + + + align:start position:0% +and from that we can solve for cosine of +theta is + + align:start position:0% +theta is + + + align:start position:0% +theta is +one half + + align:start position:0% +one half + + + align:start position:0% +one half +trace of r minus 1. + + align:start position:0% + + + + align:start position:0% + +so by the way right away that allows you + + align:start position:0% +so by the way right away that allows you + + + align:start position:0% +so by the way right away that allows you +a quick test on whether rotation matrix + + align:start position:0% +a quick test on whether rotation matrix + + + align:start position:0% +a quick test on whether rotation matrix +could even be a rotation matrix because + + align:start position:0% +could even be a rotation matrix because + + + align:start position:0% +could even be a rotation matrix because +if your trace ends up being + + align:start position:0% +if your trace ends up being + + + align:start position:0% +if your trace ends up being +too large uh or too small + + align:start position:0% +too large uh or too small + + + align:start position:0% +too large uh or too small +i.e cosine theta can only be between + + align:start position:0% +i.e cosine theta can only be between + + + align:start position:0% +i.e cosine theta can only be between +plus and minus one so that limits the + + align:start position:0% +plus and minus one so that limits the + + + align:start position:0% +plus and minus one so that limits the +value of the trace + + align:start position:0% +value of the trace + + + align:start position:0% +value of the trace +so um + + align:start position:0% +so um + + + align:start position:0% +so um +that's a lot cheaper than + + align:start position:0% +that's a lot cheaper than + + + align:start position:0% +that's a lot cheaper than +checking whether it's also orthonormal + + align:start position:0% + + + + align:start position:0% + +now + + align:start position:0% +now + + + align:start position:0% +now +that's the way to get the angle + + align:start position:0% +that's the way to get the angle + + + align:start position:0% +that's the way to get the angle +it's not a good way + + align:start position:0% +it's not a good way + + + align:start position:0% +it's not a good way +because the problems near theta + + align:start position:0% +because the problems near theta + + + align:start position:0% +because the problems near theta +equals zero right because we we have + + align:start position:0% +equals zero right because we we have + + + align:start position:0% +equals zero right because we we have +that that thing we're up on the curve + + align:start position:0% +that that thing we're up on the curve + + + align:start position:0% +that that thing we're up on the curve +and a tiny change in the height + + align:start position:0% +and a tiny change in the height + + + align:start position:0% +and a tiny change in the height +potentially corresponds to a large + + align:start position:0% +potentially corresponds to a large + + + align:start position:0% +potentially corresponds to a large +change in + + align:start position:0% +change in + + + align:start position:0% +change in +in theta + + align:start position:0% + + + + align:start position:0% + +right + + align:start position:0% +right + + + align:start position:0% +right +and similarly + + align:start position:0% + + + + align:start position:0% + +so yes this is true but that's not the + + align:start position:0% +so yes this is true but that's not the + + + align:start position:0% +so yes this is true but that's not the +way to compute theta so what do we do + + align:start position:0% +way to compute theta so what do we do + + + align:start position:0% +way to compute theta so what do we do +well we use the off-diagonal elements + + align:start position:0% +well we use the off-diagonal elements + + + align:start position:0% +well we use the off-diagonal elements +right because the off-diagonal elements + + align:start position:0% +right because the off-diagonal elements + + + align:start position:0% +right because the off-diagonal elements +all depend on the sine of theta over two + + align:start position:0% +all depend on the sine of theta over two + + + align:start position:0% +all depend on the sine of theta over two +and then it depends on whether we're + + align:start position:0% +and then it depends on whether we're + + + align:start position:0% +and then it depends on whether we're +going to use + + align:start position:0% +going to use + + + align:start position:0% +going to use +the symmetric part like q x q y + + align:start position:0% +the symmetric part like q x q y + + + align:start position:0% +the symmetric part like q x q y +which would then depend on sine squared + + align:start position:0% +which would then depend on sine squared + + + align:start position:0% +which would then depend on sine squared +of theta over two or the asymmetric part + + align:start position:0% +of theta over two or the asymmetric part + + + align:start position:0% +of theta over two or the asymmetric part +which is q zero q z which is going to + + align:start position:0% +which is q zero q z which is going to + + + align:start position:0% +which is q zero q z which is going to +depend on sine theta over two cosine + + align:start position:0% +depend on sine theta over two cosine + + + align:start position:0% +depend on sine theta over two cosine +theta over two which is the double angle + + align:start position:0% +theta over two which is the double angle + + + align:start position:0% +theta over two which is the double angle +formula for sine theta so anyway need to + + align:start position:0% +formula for sine theta so anyway need to + + + align:start position:0% +formula for sine theta so anyway need to +get sine theta + + align:start position:0% +get sine theta + + + align:start position:0% +get sine theta +so that you can then use a tan 2 and + + align:start position:0% +so that you can then use a tan 2 and + + + align:start position:0% +so that you can then use a tan 2 and +avoid that problem because where this + + align:start position:0% +avoid that problem because where this + + + align:start position:0% +avoid that problem because where this +one is bad sine theta is good so + + align:start position:0% +one is bad sine theta is good so + + + align:start position:0% +one is bad sine theta is good so +okay so that's one way to go um + + align:start position:0% +okay so that's one way to go um + + + align:start position:0% +okay so that's one way to go um +but to make it uh + + align:start position:0% +but to make it uh + + + align:start position:0% +but to make it uh +really explicit let's actually + + align:start position:0% +really explicit let's actually + + + align:start position:0% +really explicit let's actually +give a full inversion formula + + align:start position:0% + + + + align:start position:0% + +and i do this mostly to vaccinate you + + align:start position:0% +and i do this mostly to vaccinate you + + + align:start position:0% +and i do this mostly to vaccinate you +against conversion formulas that have + + align:start position:0% +against conversion formulas that have + + + align:start position:0% +against conversion formulas that have +been published + + align:start position:0% +been published + + + align:start position:0% +been published +because they are not good so + + align:start position:0% +because they are not good so + + + align:start position:0% +because they are not good so +in the sense in this kind of sense well + + align:start position:0% +in the sense in this kind of sense well + + + align:start position:0% +in the sense in this kind of sense well +yeah mathematically you know you're done + + align:start position:0% +yeah mathematically you know you're done + + + align:start position:0% +yeah mathematically you know you're done +you've got this but actually in terms of + + align:start position:0% +you've got this but actually in terms of + + + align:start position:0% +you've got this but actually in terms of +numerical accuracy uh no + + align:start position:0% +numerical accuracy uh no + + + align:start position:0% +numerical accuracy uh no +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +given the three by three matrix + + align:start position:0% +given the three by three matrix + + + align:start position:0% +given the three by three matrix +r + + align:start position:0% +r + + + align:start position:0% +r +we can compute various sums + + align:start position:0% +we can compute various sums + + + align:start position:0% +we can compute various sums +and let's start with a diagonal + + align:start position:0% +and let's start with a diagonal + + + align:start position:0% +and let's start with a diagonal +so we've got our three by three matrix + + align:start position:0% +so we've got our three by three matrix + + + align:start position:0% +so we've got our three by three matrix +over there + + align:start position:0% +over there + + + align:start position:0% +over there +and if we end up with uh + + align:start position:0% +and if we end up with uh + + + align:start position:0% +and if we end up with uh +the diagonal we we get that if we add + + align:start position:0% +the diagonal we we get that if we add + + + align:start position:0% +the diagonal we we get that if we add +one right there's that one + + align:start position:0% +one right there's that one + + + align:start position:0% +one right there's that one +then we can combine it in various other + + align:start position:0% +then we can combine it in various other + + + align:start position:0% +then we can combine it in various other +ways + + align:start position:0% + + + + align:start position:0% + +this is sort of like you know try all + + align:start position:0% +this is sort of like you know try all + + + align:start position:0% +this is sort of like you know try all +possible ways of subtracting and adding + + align:start position:0% +possible ways of subtracting and adding + + + align:start position:0% +possible ways of subtracting and adding +terms on the diagonal + + align:start position:0% +terms on the diagonal + + + align:start position:0% +terms on the diagonal +as if the off diagonals didn't exist + + align:start position:0% + + + + align:start position:0% + +and ta-da uh now we just take square + + align:start position:0% +and ta-da uh now we just take square + + + align:start position:0% +and ta-da uh now we just take square +roots + + align:start position:0% +roots + + + align:start position:0% +roots +so so that's one approach + + align:start position:0% +so so that's one approach + + + align:start position:0% +so so that's one approach +um of course the problem is + + align:start position:0% +um of course the problem is + + + align:start position:0% +um of course the problem is +there's a sine ambiguity ambiguity + + align:start position:0% +there's a sine ambiguity ambiguity + + + align:start position:0% +there's a sine ambiguity ambiguity +right because in each case we can + + align:start position:0% +right because in each case we can + + + align:start position:0% +right because in each case we can +compute these uh + + align:start position:0% +compute these uh + + + align:start position:0% +compute these uh +sums and differences + + align:start position:0% +sums and differences + + + align:start position:0% +sums and differences +and then + + align:start position:0% +and then + + + align:start position:0% +and then +divide by four and take the square root + + align:start position:0% +divide by four and take the square root + + + align:start position:0% +divide by four and take the square root +and we've got one component of the + + align:start position:0% +and we've got one component of the + + + align:start position:0% +and we've got one component of the +quaternion + + align:start position:0% +quaternion + + + align:start position:0% +quaternion +but we don't know whether it's plus or + + align:start position:0% +but we don't know whether it's plus or + + + align:start position:0% +but we don't know whether it's plus or +minus and yeah we know that + + align:start position:0% +minus and yeah we know that + + + align:start position:0% +minus and yeah we know that +plus q is the same as minus q but this + + align:start position:0% +plus q is the same as minus q but this + + + align:start position:0% +plus q is the same as minus q but this +is more this allows us + + align:start position:0% +is more this allows us + + + align:start position:0% +is more this allows us +uh + + align:start position:0% +uh + + + align:start position:0% +uh +16 different sign choices + + align:start position:0% +16 different sign choices + + + align:start position:0% +16 different sign choices +so even if you allow for the flipping of + + align:start position:0% +so even if you allow for the flipping of + + + align:start position:0% +so even if you allow for the flipping of +the sign of the quaternion that leaves + + align:start position:0% +the sign of the quaternion that leaves + + + align:start position:0% +the sign of the quaternion that leaves +us with eight so that's + + align:start position:0% +us with eight so that's + + + align:start position:0% +us with eight so that's +that means that we shouldn't rely on + + align:start position:0% +that means that we shouldn't rely on + + + align:start position:0% +that means that we shouldn't rely on +this method alone + + align:start position:0% +this method alone + + + align:start position:0% +this method alone +but what we can do is uh + + align:start position:0% +but what we can do is uh + + + align:start position:0% +but what we can do is uh +compute these and then pick the largest + + align:start position:0% +compute these and then pick the largest + + + align:start position:0% +compute these and then pick the largest +for numerical accuracy + + align:start position:0% +for numerical accuracy + + + align:start position:0% +for numerical accuracy +and solve for it + + align:start position:0% + + + + align:start position:0% + +so you know suppose q y is + + align:start position:0% +so you know suppose q y is + + + align:start position:0% +so you know suppose q y is +suppose this sum is the largest + + align:start position:0% +suppose this sum is the largest + + + align:start position:0% +suppose this sum is the largest +then we'll use it and arbitrarily use + + align:start position:0% +then we'll use it and arbitrarily use + + + align:start position:0% +then we'll use it and arbitrarily use +the positive version + + align:start position:0% +the positive version + + + align:start position:0% +the positive version +because uh we have that minus q is the + + align:start position:0% +because uh we have that minus q is the + + + align:start position:0% +because uh we have that minus q is the +same as q + + align:start position:0% +same as q + + + align:start position:0% +same as q +so we can pick we can make one arbitrary + + align:start position:0% +so we can pick we can make one arbitrary + + + align:start position:0% +so we can pick we can make one arbitrary +choice + + align:start position:0% +choice + + + align:start position:0% +choice +and + + align:start position:0% +and + + + align:start position:0% +and +solve for that let's call that q i + + align:start position:0% +solve for that let's call that q i + + + align:start position:0% +solve for that let's call that q i +and then we need to go to the off + + align:start position:0% +and then we need to go to the off + + + align:start position:0% +and then we need to go to the off +diagonals and fortunately + + align:start position:0% +diagonals and fortunately + + + align:start position:0% +diagonals and fortunately +they're symmetric and asymmetric parts + + align:start position:0% +they're symmetric and asymmetric parts + + + align:start position:0% +they're symmetric and asymmetric parts +that we can pull out + + align:start position:0% + + + + align:start position:0% + +now + + align:start position:0% +now + + + align:start position:0% +now +this is a bit more involved than the + + align:start position:0% +this is a bit more involved than the + + + align:start position:0% +this is a bit more involved than the +published methods + + align:start position:0% +published methods + + + align:start position:0% +published methods +but + + align:start position:0% +but + + + align:start position:0% +but +it works + + align:start position:0% +it works + + + align:start position:0% +it works +it's + + align:start position:0% +it's + + + align:start position:0% +it's +resistant it's robust it's resistant to + + align:start position:0% +resistant it's robust it's resistant to + + + align:start position:0% +resistant it's robust it's resistant to +numerical problems + + align:start position:0% + + + + align:start position:0% + +so by adding and subtracting + + align:start position:0% +so by adding and subtracting + + + align:start position:0% +so by adding and subtracting +corresponding diag off-diagonal parts we + + align:start position:0% +corresponding diag off-diagonal parts we + + + align:start position:0% +corresponding diag off-diagonal parts we +get six relationships you know more than + + align:start position:0% +get six relationships you know more than + + + align:start position:0% +get six relationships you know more than +we need + + align:start position:0% +we need + + + align:start position:0% +we need +but + + align:start position:0% +but + + + align:start position:0% +but +the way this works is we've picked one + + align:start position:0% +the way this works is we've picked one + + + align:start position:0% +the way this works is we've picked one +of these and solved from the diagonal + + align:start position:0% +of these and solved from the diagonal + + + align:start position:0% +of these and solved from the diagonal +and then we go into three of these and + + align:start position:0% +and then we go into three of these and + + + align:start position:0% +and then we go into three of these and +solve for the rest right so for example + + align:start position:0% +solve for the rest right so for example + + + align:start position:0% +solve for the rest right so for example +if we solve for q y + + align:start position:0% +if we solve for q y + + + align:start position:0% +if we solve for q y +uh this involves q y + + align:start position:0% +uh this involves q y + + + align:start position:0% +uh this involves q y +this involves q y and this involves q y + + align:start position:0% +this involves q y and this involves q y + + + align:start position:0% +this involves q y and this involves q y +so we pick those three to solve for q + + align:start position:0% +so we pick those three to solve for q + + + align:start position:0% +so we pick those three to solve for q +zero q x and q and q z so + + align:start position:0% +zero q x and q and q z so + + + align:start position:0% +zero q x and q and q z so +then you know correspondingly if we have + + align:start position:0% +then you know correspondingly if we have + + + align:start position:0% +then you know correspondingly if we have +so that's + + align:start position:0% +so that's + + + align:start position:0% +so that's +a direct way of going from quaternion to + + align:start position:0% +a direct way of going from quaternion to + + + align:start position:0% +a direct way of going from quaternion to +rotation matrix i mean we can also go + + align:start position:0% +rotation matrix i mean we can also go + + + align:start position:0% +rotation matrix i mean we can also go +indirectly we can first find axis and + + align:start position:0% +indirectly we can first find axis and + + + align:start position:0% +indirectly we can first find axis and +angle and then + + align:start position:0% +angle and then + + + align:start position:0% +angle and then +write the rotation matrix in terms of + + align:start position:0% +write the rotation matrix in terms of + + + align:start position:0% +write the rotation matrix in terms of +axis and angle so + + align:start position:0% +axis and angle so + + + align:start position:0% +axis and angle so +and it's it's more complicated mostly + + align:start position:0% +and it's it's more complicated mostly + + + align:start position:0% +and it's it's more complicated mostly +because + + align:start position:0% +because + + + align:start position:0% +because +we've got nine numbers and they could be + + align:start position:0% +we've got nine numbers and they could be + + + align:start position:0% +we've got nine numbers and they could be +noisy and we'd like to get the best + + align:start position:0% +noisy and we'd like to get the best + + + align:start position:0% +noisy and we'd like to get the best +possible result + + align:start position:0% +possible result + + + align:start position:0% +possible result +uh out of those nine numbers + + align:start position:0% + + + + align:start position:0% + +okay so we've uh out of the 56 ways of + + align:start position:0% +okay so we've uh out of the 56 ways of + + + align:start position:0% +okay so we've uh out of the 56 ways of +converting between different + + align:start position:0% +converting between different + + + align:start position:0% +converting between different +representations we've we've done uh four + + align:start position:0% +representations we've we've done uh four + + + align:start position:0% +representations we've we've done uh four +and that that's that should be enough so + + align:start position:0% +and that that's that should be enough so + + + align:start position:0% +and that that's that should be enough so +we can convert back and forth between + + align:start position:0% +we can convert back and forth between + + + align:start position:0% +we can convert back and forth between +the things that we're + + align:start position:0% +the things that we're + + + align:start position:0% +the things that we're +more familiar with + + align:start position:0% +more familiar with + + + align:start position:0% +more familiar with +maybe not between poorly spin matrices + + align:start position:0% +maybe not between poorly spin matrices + + + align:start position:0% +maybe not between poorly spin matrices +but + + align:start position:0% +but + + + align:start position:0% +but +we don't use those much + + align:start position:0% +we don't use those much + + + align:start position:0% +we don't use those much +except in quantum mechanics + + align:start position:0% +except in quantum mechanics + + + align:start position:0% +except in quantum mechanics +okay um + + align:start position:0% +okay um + + + align:start position:0% +okay um +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +and you know you did some of this in the + + align:start position:0% +and you know you did some of this in the + + + align:start position:0% +and you know you did some of this in the +homework and i don't want to repeat that + + align:start position:0% +homework and i don't want to repeat that + + + align:start position:0% +homework and i don't want to repeat that +but let me talk about something in + + align:start position:0% +but let me talk about something in + + + align:start position:0% +but let me talk about something in +particular uh scaling + + align:start position:0% +particular uh scaling + + + align:start position:0% +particular uh scaling +so so far + + align:start position:0% +so so far + + + align:start position:0% +so so far +we'd + + align:start position:0% + + + + align:start position:0% + +assume that our coordinate system + + align:start position:0% +assume that our coordinate system + + + align:start position:0% +assume that our coordinate system +transformations were rotation and + + align:start position:0% +transformations were rotation and + + + align:start position:0% +transformations were rotation and +translation + + align:start position:0% +translation + + + align:start position:0% +translation +and in many cases that's all there is + + align:start position:0% +and in many cases that's all there is + + + align:start position:0% +and in many cases that's all there is +if we have actual + + align:start position:0% +if we have actual + + + align:start position:0% +if we have actual +time of flight data to measuring + + align:start position:0% +time of flight data to measuring + + + align:start position:0% +time of flight data to measuring +distances + + align:start position:0% +distances + + + align:start position:0% +distances +there's um + + align:start position:0% +there's um + + + align:start position:0% +there's um +usually no question about the scale + + align:start position:0% +usually no question about the scale + + + align:start position:0% +usually no question about the scale +factor because we know + + align:start position:0% +factor because we know + + + align:start position:0% +factor because we know +the speed of light with you know more + + align:start position:0% +the speed of light with you know more + + + align:start position:0% +the speed of light with you know more +precision than + + align:start position:0% +precision than + + + align:start position:0% +precision than +you can throw a stick at um although + + align:start position:0% +you can throw a stick at um although + + + align:start position:0% +you can throw a stick at um although +there's often an error in offset + + align:start position:0% +there's often an error in offset + + + align:start position:0% +there's often an error in offset +and + + align:start position:0% +and + + + align:start position:0% +and +so um + + align:start position:0% +so um + + + align:start position:0% +so um +how do we get into scale well it's quite + + align:start position:0% +how do we get into scale well it's quite + + + align:start position:0% +how do we get into scale well it's quite +easy to get into scale for example if we + + align:start position:0% +easy to get into scale for example if we + + + align:start position:0% +easy to get into scale for example if we +get the baseline wrong + + align:start position:0% +get the baseline wrong + + + align:start position:0% +get the baseline wrong +so our plane is flying along taking one + + align:start position:0% +so our plane is flying along taking one + + + align:start position:0% +so our plane is flying along taking one +picture taking another picture and we + + align:start position:0% +picture taking another picture and we + + + align:start position:0% +picture taking another picture and we +know the speed of the plane and we know + + align:start position:0% +know the speed of the plane and we know + + + align:start position:0% +know the speed of the plane and we know +the time so we know how far we know the + + align:start position:0% +the time so we know how far we know the + + + align:start position:0% +the time so we know how far we know the +baseline but how accurately do we really + + align:start position:0% +baseline but how accurately do we really + + + align:start position:0% +baseline but how accurately do we really +know it + + align:start position:0% +know it + + + align:start position:0% +know it +uh so + + align:start position:0% +uh so + + + align:start position:0% +uh so +uh if we are trying to patch together + + align:start position:0% +uh if we are trying to patch together + + + align:start position:0% +uh if we are trying to patch together +pieces of the terrain that were obtained + + align:start position:0% +pieces of the terrain that were obtained + + + align:start position:0% +pieces of the terrain that were obtained +with successive you know two camera + + align:start position:0% +with successive you know two camera + + + align:start position:0% +with successive you know two camera +positions + + align:start position:0% +positions + + + align:start position:0% +positions +then we should allow for some small + + align:start position:0% +then we should allow for some small + + + align:start position:0% +then we should allow for some small +difference in the scaling because we + + align:start position:0% +difference in the scaling because we + + + align:start position:0% +difference in the scaling because we +don't we know the distance pretty + + align:start position:0% +don't we know the distance pretty + + + align:start position:0% +don't we know the distance pretty +accurately but not perfectly and you + + align:start position:0% +accurately but not perfectly and you + + + align:start position:0% +accurately but not perfectly and you +know we're looking for very high + + align:start position:0% +know we're looking for very high + + + align:start position:0% +know we're looking for very high +accuracy in topographic reconstruction + + align:start position:0% +accuracy in topographic reconstruction + + + align:start position:0% +accuracy in topographic reconstruction +so how to deal with that + + align:start position:0% +so how to deal with that + + + align:start position:0% +so how to deal with that +well + + align:start position:0% +well + + + align:start position:0% +well +let's assume we've uh + + align:start position:0% +let's assume we've uh + + + align:start position:0% +let's assume we've uh +and this isn't hard + + align:start position:0% +and this isn't hard + + + align:start position:0% +and this isn't hard +we again find that centroid maps to + + align:start position:0% +we again find that centroid maps to + + + align:start position:0% +we again find that centroid maps to +centroid even with the introduction of + + align:start position:0% +centroid even with the introduction of + + + align:start position:0% +centroid even with the introduction of +scaling uh that's very easy just + + align:start position:0% +scaling uh that's very easy just + + + align:start position:0% +scaling uh that's very easy just +differentiate with respect to + + align:start position:0% +differentiate with respect to + + + align:start position:0% +differentiate with respect to +translation set the result equal to zero + + align:start position:0% +translation set the result equal to zero + + + align:start position:0% +translation set the result equal to zero +and then we move the origin to the + + align:start position:0% +and then we move the origin to the + + + align:start position:0% +and then we move the origin to the +centroid and we get these prime + + align:start position:0% +centroid and we get these prime + + + align:start position:0% +centroid and we get these prime +coordinates so now uh + + align:start position:0% +coordinates so now uh + + + align:start position:0% +coordinates so now uh +let's look at this + + align:start position:0% + + + + align:start position:0% + +so here's a possible version of the + + align:start position:0% +so here's a possible version of the + + + align:start position:0% +so here's a possible version of the +problem we're trying to solve that now + + align:start position:0% +problem we're trying to solve that now + + + align:start position:0% +problem we're trying to solve that now +in the we've got rid of translation by + + align:start position:0% +in the we've got rid of translation by + + + align:start position:0% +in the we've got rid of translation by +moving to centroid uh and now we have an + + align:start position:0% +moving to centroid uh and now we have an + + + align:start position:0% +moving to centroid uh and now we have an +unknown rotation and we have an unknown + + align:start position:0% +unknown rotation and we have an unknown + + + align:start position:0% +unknown rotation and we have an unknown +scaling that that's a new part and so we + + align:start position:0% +scaling that that's a new part and so we + + + align:start position:0% +scaling that that's a new part and so we +might want to set up a least squares + + align:start position:0% +might want to set up a least squares + + + align:start position:0% +might want to set up a least squares +problem + + align:start position:0% + + + + align:start position:0% + +and of course the norm is the dot + + align:start position:0% +and of course the norm is the dot + + + align:start position:0% +and of course the norm is the dot +product of this thing with itself so we + + align:start position:0% +product of this thing with itself so we + + + align:start position:0% +product of this thing with itself so we +can actually multiply it out we get four + + align:start position:0% +can actually multiply it out we get four + + + align:start position:0% +can actually multiply it out we get four +terms + + align:start position:0% +terms + + + align:start position:0% +terms +and then the sum of those four terms is + + align:start position:0% +and then the sum of those four terms is + + + align:start position:0% +and then the sum of those four terms is +the + + align:start position:0% +the + + + align:start position:0% +the +sum of four sums + + align:start position:0% +sum of four sums + + + align:start position:0% +sum of four sums +and so we end up with + + align:start position:0% +and so we end up with + + + align:start position:0% +and so we end up with +so this is very similar to + + align:start position:0% +so this is very similar to + + + align:start position:0% +so this is very similar to +what we've done before + + align:start position:0% + + + + align:start position:0% + +and how do we find the optimum well of + + align:start position:0% +and how do we find the optimum well of + + + align:start position:0% +and how do we find the optimum well of +course we just differentiate with + + align:start position:0% +course we just differentiate with + + + align:start position:0% +course we just differentiate with +respect to s this is particularly easy + + align:start position:0% +respect to s this is particularly easy + + + align:start position:0% +respect to s this is particularly easy +now it's just a scalar and we set the + + align:start position:0% +now it's just a scalar and we set the + + + align:start position:0% +now it's just a scalar and we set the +result equal to zero and the first term + + align:start position:0% +result equal to zero and the first term + + + align:start position:0% +result equal to zero and the first term +drops out and then we get the second + + align:start position:0% +drops out and then we get the second + + + align:start position:0% +drops out and then we get the second +term + + align:start position:0% + + + + align:start position:0% + +oh here of course we use the fact that + + align:start position:0% +oh here of course we use the fact that + + + align:start position:0% +oh here of course we use the fact that +this the size of this vector is the same + + align:start position:0% +this the size of this vector is the same + + + align:start position:0% +this the size of this vector is the same +as the size of the rotated vector so + + align:start position:0% +as the size of the rotated vector so + + + align:start position:0% +as the size of the rotated vector so +rotation doesn't change the size okay + + align:start position:0% +rotation doesn't change the size okay + + + align:start position:0% +rotation doesn't change the size okay +this is equal to 0 and so we can solve + + align:start position:0% +this is equal to 0 and so we can solve + + + align:start position:0% +this is equal to 0 and so we can solve +for s + + align:start position:0% +for s + + + align:start position:0% +for s +well let's give these things names + + align:start position:0% +well let's give these things names + + + align:start position:0% +well let's give these things names +let's call this + + align:start position:0% +let's call this + + + align:start position:0% +let's call this +sr + + align:start position:0% +sr + + + align:start position:0% +sr +so we don't have to write them too many + + align:start position:0% +so we don't have to write them too many + + + align:start position:0% +so we don't have to write them too many +times and let's call this d + + align:start position:0% +times and let's call this d + + + align:start position:0% +times and let's call this d +and call this is l + + align:start position:0% +and call this is l + + + align:start position:0% +and call this is l +so we have + + align:start position:0% +so we have + + + align:start position:0% +so we have +uh + + align:start position:0% +uh + + + align:start position:0% +uh +s equals d of s + + align:start position:0% +s equals d of s + + + align:start position:0% +s equals d of s +l + + align:start position:0% +l + + + align:start position:0% +l +right we just solve this for d we can + + align:start position:0% +right we just solve this for d we can + + + align:start position:0% +right we just solve this for d we can +forget the two + + align:start position:0% +forget the two + + + align:start position:0% +forget the two +and and so + + align:start position:0% +and and so + + + align:start position:0% +and and so +we don't at this point know the answer + + align:start position:0% +we don't at this point know the answer + + + align:start position:0% +we don't at this point know the answer +because we haven't got the rotation yet + + align:start position:0% +because we haven't got the rotation yet + + + align:start position:0% +because we haven't got the rotation yet +but with in the same situation as we + + align:start position:0% +but with in the same situation as we + + + align:start position:0% +but with in the same situation as we +with translation where + + align:start position:0% +with translation where + + + align:start position:0% +with translation where +we can remove the scale factor from + + align:start position:0% +we can remove the scale factor from + + + align:start position:0% +we can remove the scale factor from +consideration now + + align:start position:0% +consideration now + + + align:start position:0% +consideration now +and then at the end we go back and use + + align:start position:0% +and then at the end we go back and use + + + align:start position:0% +and then at the end we go back and use +this formula + + align:start position:0% +this formula + + + align:start position:0% +this formula +to + + align:start position:0% + + + + align:start position:0% + +compute the + + align:start position:0% +compute the + + + align:start position:0% +compute the +scale factors + + align:start position:0% + + + + align:start position:0% + +so that sort of keeps everything coupled + + align:start position:0% +so that sort of keeps everything coupled + + + align:start position:0% +so that sort of keeps everything coupled +that + + align:start position:0% +that + + + align:start position:0% +that +we can't do it independently of rotation + + align:start position:0% +we can't do it independently of rotation + + + align:start position:0% +we can't do it independently of rotation +now uh we talked earlier about um + + align:start position:0% +now uh we talked earlier about um + + + align:start position:0% +now uh we talked earlier about um +symmetry you know why are we rotating + + align:start position:0% +symmetry you know why are we rotating + + + align:start position:0% +symmetry you know why are we rotating +from left coordinate to right coordinate + + align:start position:0% +from left coordinate to right coordinate + + + align:start position:0% +from left coordinate to right coordinate +rather than from right corner to the + + align:start position:0% +rather than from right corner to the + + + align:start position:0% +rather than from right corner to the +left coordinate and + + align:start position:0% +left coordinate and + + + align:start position:0% +left coordinate and +a method should really be symmetrical in + + align:start position:0% +a method should really be symmetrical in + + + align:start position:0% +a method should really be symmetrical in +that if you compute the inverse you + + align:start position:0% +that if you compute the inverse you + + + align:start position:0% +that if you compute the inverse you +should get the inverse of you know so + + align:start position:0% +should get the inverse of you know so + + + align:start position:0% +should get the inverse of you know so +the rotational matrix you get should be + + align:start position:0% +the rotational matrix you get should be + + + align:start position:0% +the rotational matrix you get should be +the transpose of the rotational matrix + + align:start position:0% +the transpose of the rotational matrix + + + align:start position:0% +the transpose of the rotational matrix +and so on so so here if we now go from + + align:start position:0% +and so on so so here if we now go from + + + align:start position:0% +and so on so so here if we now go from +the + + align:start position:0% +the + + + align:start position:0% +the +the other way around + + align:start position:0% +the other way around + + + align:start position:0% +the other way around +if we look at this problem + + align:start position:0% + + + + align:start position:0% + +then we expect to get a scale factor + + align:start position:0% +then we expect to get a scale factor + + + align:start position:0% +then we expect to get a scale factor +that's the inverse of that scale factor + + align:start position:0% +that's the inverse of that scale factor + + + align:start position:0% +that's the inverse of that scale factor +right because we're going from + + align:start position:0% +right because we're going from + + + align:start position:0% +right because we're going from +right coordinate system to left we're + + align:start position:0% +right coordinate system to left we're + + + align:start position:0% +right coordinate system to left we're +going from left to right before and if + + align:start position:0% +going from left to right before and if + + + align:start position:0% +going from left to right before and if +you actually work it out + + align:start position:0% + + + + align:start position:0% + +you get that + + align:start position:0% +you get that + + + align:start position:0% +you get that +so again you can do it + + align:start position:0% +so again you can do it + + + align:start position:0% +so again you can do it +but it's not the same answer + + align:start position:0% +but it's not the same answer + + + align:start position:0% +but it's not the same answer +it's not the inverse of that what we + + align:start position:0% +it's not the inverse of that what we + + + align:start position:0% +it's not the inverse of that what we +would expect is that + + align:start position:0% +would expect is that + + + align:start position:0% +would expect is that +s prime is 1 over s + + align:start position:0% +s prime is 1 over s + + + align:start position:0% +s prime is 1 over s +and it's not + + align:start position:0% +and it's not + + + align:start position:0% +and it's not +in general + + align:start position:0% +in general + + + align:start position:0% +in general +so that suggests that this is not a good + + align:start position:0% +so that suggests that this is not a good + + + align:start position:0% +so that suggests that this is not a good +method + + align:start position:0% +method + + + align:start position:0% +method +and what's what's going on well what's + + align:start position:0% +and what's what's going on well what's + + + align:start position:0% +and what's what's going on well what's +going on is that the least squares + + align:start position:0% +going on is that the least squares + + + align:start position:0% +going on is that the least squares +method is trying to make things as the + + align:start position:0% +method is trying to make things as the + + + align:start position:0% +method is trying to make things as the +errors as small as possible and one way + + align:start position:0% +errors as small as possible and one way + + + align:start position:0% +errors as small as possible and one way +to do that is to make + + align:start position:0% +to do that is to make + + + align:start position:0% +to do that is to make +the transform coordinates smaller + + align:start position:0% +the transform coordinates smaller + + + align:start position:0% +the transform coordinates smaller +up to a point so you can kind of cheat + + align:start position:0% +up to a point so you can kind of cheat + + + align:start position:0% +up to a point so you can kind of cheat +by making the + + align:start position:0% +by making the + + + align:start position:0% +by making the +scale factor a little bit smaller than + + align:start position:0% +scale factor a little bit smaller than + + + align:start position:0% +scale factor a little bit smaller than +it it + + align:start position:0% +it it + + + align:start position:0% +it it +really should be + + align:start position:0% +really should be + + + align:start position:0% +really should be +because you're shrinking things down and + + align:start position:0% +because you're shrinking things down and + + + align:start position:0% +because you're shrinking things down and +making things smaller and then + + align:start position:0% +making things smaller and then + + + align:start position:0% +making things smaller and then +conversely if you go in the other + + align:start position:0% +conversely if you go in the other + + + align:start position:0% +conversely if you go in the other +direction you shrink down the other + + align:start position:0% +direction you shrink down the other + + + align:start position:0% +direction you shrink down the other +coordinate system so + + align:start position:0% +coordinate system so + + + align:start position:0% +coordinate system so +neither of these is really uh + + align:start position:0% +neither of these is really uh + + + align:start position:0% +neither of these is really uh +acceptable + + align:start position:0% +acceptable + + + align:start position:0% +acceptable +and so we look at another error term + + align:start position:0% +and so we look at another error term + + + align:start position:0% +and so we look at another error term +the one that you looked at in the + + align:start position:0% +the one that you looked at in the + + + align:start position:0% +the one that you looked at in the +homework problem + + align:start position:0% +homework problem + + + align:start position:0% +homework problem +in the 2d case + + align:start position:0% +in the 2d case + + + align:start position:0% +in the 2d case +and so in this case we're going to end + + align:start position:0% +and so in this case we're going to end + + + align:start position:0% +and so in this case we're going to end +up with an error that looks like this + + align:start position:0% + + + + align:start position:0% + +right where the you know srsl and d are + + align:start position:0% +right where the you know srsl and d are + + + align:start position:0% +right where the you know srsl and d are +as defined over there + + align:start position:0% +as defined over there + + + align:start position:0% +as defined over there +and that's nice because s doesn't show + + align:start position:0% +and that's nice because s doesn't show + + + align:start position:0% +and that's nice because s doesn't show +up here + + align:start position:0% +up here + + + align:start position:0% +up here +in that + + align:start position:0% +in that + + + align:start position:0% +in that +term that has the rotation in it and we + + align:start position:0% +term that has the rotation in it and we + + + align:start position:0% +term that has the rotation in it and we +just have these other terms + + align:start position:0% +just have these other terms + + + align:start position:0% +just have these other terms +and so we can just differentiate with + + align:start position:0% +and so we can just differentiate with + + + align:start position:0% +and so we can just differentiate with +respect to s set the result equal to + + align:start position:0% +respect to s set the result equal to + + + align:start position:0% +respect to s set the result equal to +zero + + align:start position:0% + + + + align:start position:0% + +right because the derivative of that + + align:start position:0% +right because the derivative of that + + + align:start position:0% +right because the derivative of that +zero with respect to s is zero and and + + align:start position:0% +zero with respect to s is zero and and + + + align:start position:0% +zero with respect to s is zero and and +so that means that s squared is + + align:start position:0% +so that means that s squared is + + + align:start position:0% +so that means that s squared is +s + + align:start position:0% +s + + + align:start position:0% +s +r over s l + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +now + + align:start position:0% +now + + + align:start position:0% +now +if i + + align:start position:0% +if i + + + align:start position:0% +if i +go in the other direction i'm going to + + align:start position:0% +go in the other direction i'm going to + + + align:start position:0% +go in the other direction i'm going to +get + + align:start position:0% +get + + + align:start position:0% +get +s bar squared + + align:start position:0% +s bar squared + + + align:start position:0% +s bar squared +is sl over sr + + align:start position:0% +is sl over sr + + + align:start position:0% +is sl over sr +and that is + + align:start position:0% +and that is + + + align:start position:0% +and that is +the inverse + + align:start position:0% +the inverse + + + align:start position:0% +the inverse +so so that method is much to be + + align:start position:0% +so so that method is much to be + + + align:start position:0% +so so that method is much to be +preferred + + align:start position:0% +preferred + + + align:start position:0% +preferred +it also has the property that + + align:start position:0% +it also has the property that + + + align:start position:0% +it also has the property that +we don't need correspondences + + align:start position:0% + + + + align:start position:0% + +so it's just like a translation + + align:start position:0% +so it's just like a translation + + + align:start position:0% +so it's just like a translation +where we are able to map centroid to + + align:start position:0% +where we are able to map centroid to + + + align:start position:0% +where we are able to map centroid to +centroid we didn't need correspondences + + align:start position:0% +centroid we didn't need correspondences + + + align:start position:0% +centroid we didn't need correspondences +for that uh here it's very convenient + + align:start position:0% +for that uh here it's very convenient + + + align:start position:0% +for that uh here it's very convenient +that we don't need the the only term + + align:start position:0% +that we don't need the the only term + + + align:start position:0% +that we don't need the the only term +that depends on correspondence is that + + align:start position:0% +that depends on correspondence is that + + + align:start position:0% +that depends on correspondence is that +one we only need these others which + + align:start position:0% +one we only need these others which + + + align:start position:0% +one we only need these others which +basically say you know you've got this + + align:start position:0% +basically say you know you've got this + + + align:start position:0% +basically say you know you've got this +cloud of points how big is it and then + + align:start position:0% +cloud of points how big is it and then + + + align:start position:0% +cloud of points how big is it and then +you have the other cloud of points how + + align:start position:0% +you have the other cloud of points how + + + align:start position:0% +you have the other cloud of points how +big is it well uh just + + align:start position:0% +big is it well uh just + + + align:start position:0% +big is it well uh just +the scale factor is the ratio of those + + align:start position:0% +the scale factor is the ratio of those + + + align:start position:0% +the scale factor is the ratio of those +two sizes it's very intuitive so + + align:start position:0% +two sizes it's very intuitive so + + + align:start position:0% +two sizes it's very intuitive so +okay + + align:start position:0% + + + + align:start position:0% + +so that leaves us with the + + align:start position:0% +so that leaves us with the + + + align:start position:0% +so that leaves us with the +problem of + + align:start position:0% +problem of + + + align:start position:0% +problem of +so we can deal with translation and + + align:start position:0% +so we can deal with translation and + + + align:start position:0% +so we can deal with translation and +scaling + + align:start position:0% +scaling + + + align:start position:0% +scaling +in a + + align:start position:0% +in a + + + align:start position:0% +in a +correspondence-free way + + align:start position:0% +correspondence-free way + + + align:start position:0% +correspondence-free way +and also free of rotation we don't need + + align:start position:0% +and also free of rotation we don't need + + + align:start position:0% +and also free of rotation we don't need +to take into account rotation + + align:start position:0% +to take into account rotation + + + align:start position:0% +to take into account rotation +well + + align:start position:0% +well + + + align:start position:0% +well +we can separate the problems + + align:start position:0% +we can separate the problems + + + align:start position:0% +we can separate the problems +so that leaves us with + + align:start position:0% +so that leaves us with + + + align:start position:0% +so that leaves us with +you know the rotation part and we spent + + align:start position:0% +you know the rotation part and we spent + + + align:start position:0% +you know the rotation part and we spent +some time uh on that so i won't + + align:start position:0% +some time uh on that so i won't + + + align:start position:0% +some time uh on that so i won't +review that in great detail + + align:start position:0% +review that in great detail + + + align:start position:0% +review that in great detail +just + + align:start position:0% + + + + align:start position:0% + +note that in the end + + align:start position:0% +note that in the end + + + align:start position:0% +note that in the end +we have + + align:start position:0% +we have + + + align:start position:0% +we have +this to maximize + + align:start position:0% + + + + align:start position:0% + +right because this this was a + + align:start position:0% +right because this this was a + + + align:start position:0% +right because this this was a +minimization + + align:start position:0% +minimization + + + align:start position:0% +minimization +but we have the negative sign so this + + align:start position:0% +but we have the negative sign so this + + + align:start position:0% +but we have the negative sign so this +has to be maximized and n of course is a + + align:start position:0% +has to be maximized and n of course is a + + + align:start position:0% +has to be maximized and n of course is a +four by four matrix which we can show is + + align:start position:0% +four by four matrix which we can show is + + + align:start position:0% +four by four matrix which we can show is +symmetric it's not uh obvious that it is + + align:start position:0% +symmetric it's not uh obvious that it is + + + align:start position:0% +symmetric it's not uh obvious that it is +and so now we have a + + align:start position:0% +and so now we have a + + + align:start position:0% +and so now we have a +calculus problem we just differentiate + + align:start position:0% +calculus problem we just differentiate + + + align:start position:0% +calculus problem we just differentiate +with respect to q + + align:start position:0% +with respect to q + + + align:start position:0% +with respect to q +and set the result equal to zero + + align:start position:0% +and set the result equal to zero + + + align:start position:0% +and set the result equal to zero +well + + align:start position:0% +well + + + align:start position:0% +well +not quite + + align:start position:0% +not quite + + + align:start position:0% +not quite +you know we have that constraint + + align:start position:0% +you know we have that constraint + + + align:start position:0% +you know we have that constraint +and it's just as well because otherwise + + align:start position:0% +and it's just as well because otherwise + + + align:start position:0% +and it's just as well because otherwise +the answer is zero + + align:start position:0% +the answer is zero + + + align:start position:0% +the answer is zero +right because that um differentiate that + + align:start position:0% +right because that um differentiate that + + + align:start position:0% +right because that um differentiate that +uh + + align:start position:0% +uh + + + align:start position:0% +uh +and you get uh two and q + + align:start position:0% +and you get uh two and q + + + align:start position:0% +and you get uh two and q +uh how do you do that well just + + align:start position:0% +uh how do you do that well just + + + align:start position:0% +uh how do you do that well just +i'm sure you remember + + align:start position:0% + + + + align:start position:0% + +these formulas + + align:start position:0% + + + + align:start position:0% + +and so on so um + + align:start position:0% + + + + align:start position:0% + +uh all in the appendix + + align:start position:0% +uh all in the appendix + + + align:start position:0% +uh all in the appendix +okay so if we set that equal to zero + + align:start position:0% +okay so if we set that equal to zero + + + align:start position:0% +okay so if we set that equal to zero +well there's a very convenient answer uh + + align:start position:0% +well there's a very convenient answer uh + + + align:start position:0% +well there's a very convenient answer uh +which is that uh q is zero or looked at + + align:start position:0% +which is that uh q is zero or looked at + + + align:start position:0% +which is that uh q is zero or looked at +another way + + align:start position:0% +another way + + + align:start position:0% +another way +if we try + + align:start position:0% +if we try + + + align:start position:0% +if we try +that's an extremum + + align:start position:0% +that's an extremum + + + align:start position:0% +that's an extremum +um + + align:start position:0% +um + + + align:start position:0% +um +well we're actually trying to maximize + + align:start position:0% +well we're actually trying to maximize + + + align:start position:0% +well we're actually trying to maximize +so we'd go the other way we would just + + align:start position:0% +so we'd go the other way we would just + + + align:start position:0% +so we'd go the other way we would just +make q grow we can make q as large as we + + align:start position:0% +make q grow we can make q as large as we + + + align:start position:0% +make q grow we can make q as large as we +like and so there's no maximum + + align:start position:0% +like and so there's no maximum + + + align:start position:0% +like and so there's no maximum +well infinity so so that's obviously not + + align:start position:0% +well infinity so so that's obviously not + + + align:start position:0% +well infinity so so that's obviously not +satisfactory we need to take into + + align:start position:0% +satisfactory we need to take into + + + align:start position:0% +satisfactory we need to take into +account the uh + + align:start position:0% +account the uh + + + align:start position:0% +account the uh +constraint and as we saw in the slides + + align:start position:0% +constraint and as we saw in the slides + + + align:start position:0% +constraint and as we saw in the slides +last time one way to do that is using + + align:start position:0% +last time one way to do that is using + + + align:start position:0% +last time one way to do that is using +lagrange multipliers + + align:start position:0% +lagrange multipliers + + + align:start position:0% +lagrange multipliers +very elegant method and it's + + align:start position:0% +very elegant method and it's + + + align:start position:0% +very elegant method and it's +described in the appendix but this is a + + align:start position:0% +described in the appendix but this is a + + + align:start position:0% +described in the appendix but this is a +special case where we can get away with + + align:start position:0% +special case where we can get away with + + + align:start position:0% +special case where we can get away with +something simpler + + align:start position:0% +something simpler + + + align:start position:0% +something simpler +called + + align:start position:0% +called + + + align:start position:0% +called +rally quotient + + align:start position:0% +rally quotient + + + align:start position:0% +rally quotient +so rally did all sorts of interesting + + align:start position:0% +so rally did all sorts of interesting + + + align:start position:0% +so rally did all sorts of interesting +things including um work in optics + + align:start position:0% +things including um work in optics + + + align:start position:0% +things including um work in optics +and + + align:start position:0% +and + + + align:start position:0% +and +he ran into this problem of trying to + + align:start position:0% +he ran into this problem of trying to + + + align:start position:0% +he ran into this problem of trying to +find uh + + align:start position:0% +find uh + + + align:start position:0% +find uh +an extremum and so he came up with the + + align:start position:0% +an extremum and so he came up with the + + + align:start position:0% +an extremum and so he came up with the +idea well + + align:start position:0% +idea well + + + align:start position:0% +idea well +how do i prevent this from running away + + align:start position:0% +how do i prevent this from running away + + + align:start position:0% +how do i prevent this from running away +by being made very large + + align:start position:0% +by being made very large + + + align:start position:0% +by being made very large +sorry this is transpose + + align:start position:0% +sorry this is transpose + + + align:start position:0% +sorry this is transpose +well + + align:start position:0% + + + + align:start position:0% + +i just divide by the size of q + + align:start position:0% +i just divide by the size of q + + + align:start position:0% +i just divide by the size of q +so there's no advantage to making q very + + align:start position:0% +so there's no advantage to making q very + + + align:start position:0% +so there's no advantage to making q very +large + + align:start position:0% +large + + + align:start position:0% +large +right so + + align:start position:0% +right so + + + align:start position:0% +right so +you know if you think about it as + + align:start position:0% +you know if you think about it as + + + align:start position:0% +you know if you think about it as +directions in a space + + align:start position:0% +directions in a space + + + align:start position:0% +directions in a space +this quantity is constant along any + + align:start position:0% +this quantity is constant along any + + + align:start position:0% +this quantity is constant along any +array + + align:start position:0% +array + + + align:start position:0% +array +right because wherever i am + + align:start position:0% +right because wherever i am + + + align:start position:0% +right because wherever i am +i'm going to divide out by the length of + + align:start position:0% +i'm going to divide out by the length of + + + align:start position:0% +i'm going to divide out by the length of +q itself so that creates a different + + align:start position:0% +q itself so that creates a different + + + align:start position:0% +q itself so that creates a different +function the one that doesn't go off to + + align:start position:0% +function the one that doesn't go off to + + + align:start position:0% +function the one that doesn't go off to +infinity but that is constant along any + + align:start position:0% +infinity but that is constant along any + + + align:start position:0% +infinity but that is constant along any +array and and that's exactly what we + + align:start position:0% +array and and that's exactly what we + + + align:start position:0% +array and and that's exactly what we +want we want to find the ray the + + align:start position:0% +want we want to find the ray the + + + align:start position:0% +want we want to find the ray the +direction of the ray that makes that as + + align:start position:0% +direction of the ray that makes that as + + + align:start position:0% +direction of the ray that makes that as +extreme as pos yeah + + align:start position:0% +extreme as pos yeah + + + align:start position:0% +extreme as pos yeah +what is the matrix + + align:start position:0% +what is the matrix + + + align:start position:0% +what is the matrix +oh + + align:start position:0% +oh + + + align:start position:0% +oh +uh so that's the thing that we got out + + align:start position:0% +uh so that's the thing that we got out + + + align:start position:0% +uh so that's the thing that we got out +of + + align:start position:0% +of + + + align:start position:0% +of +uh where it disappeared uh the + + align:start position:0% + + + + align:start position:0% + +where we took the um + + align:start position:0% + + + + align:start position:0% + +representation of a quaternion product + + align:start position:0% +representation of a quaternion product + + + align:start position:0% +representation of a quaternion product +with + + align:start position:0% +with + + + align:start position:0% +with +a four by four as a four by four uh + + align:start position:0% +a four by four as a four by four uh + + + align:start position:0% +a four by four as a four by four uh +rotational orthogonal matrix + + align:start position:0% +rotational orthogonal matrix + + + align:start position:0% +rotational orthogonal matrix +so that that's sort of the key + + align:start position:0% +so that that's sort of the key + + + align:start position:0% +so that that's sort of the key +uh no um + + align:start position:0% + + + + align:start position:0% + +where is their space well let's just + + align:start position:0% +where is their space well let's just + + + align:start position:0% +where is their space well let's just +take this + + align:start position:0% +take this + + + align:start position:0% +take this +just quick uh + + align:start position:0% +just quick uh + + + align:start position:0% +just quick uh +review of that + + align:start position:0% +review of that + + + align:start position:0% +review of that +that part + + align:start position:0% +that part + + + align:start position:0% +that part +so um + + align:start position:0% +so um + + + align:start position:0% +so um +we had + + align:start position:0% +we had + + + align:start position:0% +we had +i'm not going to copy it all out just + + align:start position:0% +i'm not going to copy it all out just + + + align:start position:0% +i'm not going to copy it all out just +the beginning so we had this sigma of + + align:start position:0% +the beginning so we had this sigma of + + + align:start position:0% +the beginning so we had this sigma of +[Music] + + align:start position:0% + + + + align:start position:0% + +right this was the thing we were trying + + align:start position:0% +right this was the thing we were trying + + + align:start position:0% +right this was the thing we were trying +to maximize + + align:start position:0% +to maximize + + + align:start position:0% +to maximize +and then we wrote + + align:start position:0% +and then we wrote + + + align:start position:0% +and then we wrote +first we took this over to the other + + align:start position:0% +first we took this over to the other + + + align:start position:0% +first we took this over to the other +side to make it more symmetrical so + + align:start position:0% + + + + align:start position:0% + +oh + + align:start position:0% +oh + + + align:start position:0% +oh +sorry + + align:start position:0% + + + + align:start position:0% + +and then we use that notation where we + + align:start position:0% +and then we use that notation where we + + + align:start position:0% +and then we use that notation where we +represented this as + + align:start position:0% + + + + align:start position:0% + +now before we expanded it the other way + + align:start position:0% +now before we expanded it the other way + + + align:start position:0% +now before we expanded it the other way +out we we converted q into a four by + + align:start position:0% +out we we converted q into a four by + + + align:start position:0% +out we we converted q into a four by +four matrix and multiplied by this uh + + align:start position:0% +four matrix and multiplied by this uh + + + align:start position:0% +four matrix and multiplied by this uh +quaternion + + align:start position:0% +quaternion + + + align:start position:0% +quaternion +and now we do it the other way around + + align:start position:0% +and now we do it the other way around + + + align:start position:0% +and now we do it the other way around +and then because this is a dot product + + align:start position:0% +and then because this is a dot product + + + align:start position:0% +and then because this is a dot product +it's that transpose and then we get q + + align:start position:0% +it's that transpose and then we get q + + + align:start position:0% +it's that transpose and then we get q +transpose + + align:start position:0% +transpose + + + align:start position:0% +transpose +r + + align:start position:0% +r + + + align:start position:0% +r +transpose l i + + align:start position:0% +transpose l i + + + align:start position:0% +transpose l i +r + + align:start position:0% + + + + align:start position:0% + +and and of course the sum of that + + align:start position:0% +and and of course the sum of that + + + align:start position:0% +and and of course the sum of that +and q doesn't depend on i so we can get + + align:start position:0% +and q doesn't depend on i so we can get + + + align:start position:0% +and q doesn't depend on i so we can get +rid of that + + align:start position:0% +rid of that + + + align:start position:0% +rid of that +so it's it's that matrix + + align:start position:0% +so it's it's that matrix + + + align:start position:0% +so it's it's that matrix +so it's derived from + + align:start position:0% + + + + align:start position:0% + +it's derived from the data from the + + align:start position:0% +it's derived from the data from the + + + align:start position:0% +it's derived from the data from the +chorus correspondences right + + align:start position:0% + + + + align:start position:0% + +okay um so + + align:start position:0% + + + + align:start position:0% + +how do we find that well now it's pretty + + align:start position:0% +how do we find that well now it's pretty + + + align:start position:0% +how do we find that well now it's pretty +straightforward calculus problem + + align:start position:0% +straightforward calculus problem + + + align:start position:0% +straightforward calculus problem +we just differentiate with respect to q + + align:start position:0% +we just differentiate with respect to q + + + align:start position:0% +we just differentiate with respect to q +and set the result equal to zero + + align:start position:0% + + + + align:start position:0% + +and you know it's a ratio so we use the + + align:start position:0% +and you know it's a ratio so we use the + + + align:start position:0% +and you know it's a ratio so we use the +rule for differentiation of a ratio + + align:start position:0% +rule for differentiation of a ratio + + + align:start position:0% +rule for differentiation of a ratio +and so first differentiate the numerator + + align:start position:0% +and so first differentiate the numerator + + + align:start position:0% +and so first differentiate the numerator +we get 2 and q + + align:start position:0% +we get 2 and q + + + align:start position:0% +we get 2 and q +divided by this + + align:start position:0% +divided by this + + + align:start position:0% +divided by this +and then we need to + + align:start position:0% +and then we need to + + + align:start position:0% +and then we need to +add + + align:start position:0% +add + + + align:start position:0% +add +uh + + align:start position:0% +uh + + + align:start position:0% +uh +you know the term involving the + + align:start position:0% +you know the term involving the + + + align:start position:0% +you know the term involving the +denominator the denominator so we get + + align:start position:0% +denominator the denominator so we get + + + align:start position:0% +denominator the denominator so we get +minus 1 over + + align:start position:0% +minus 1 over + + + align:start position:0% +minus 1 over +q dot t + + align:start position:0% +q dot t + + + align:start position:0% +q dot t +q 0 squared + + align:start position:0% +q 0 squared + + + align:start position:0% +q 0 squared +2 q + + align:start position:0% +2 q + + + align:start position:0% +2 q +and + + align:start position:0% +and + + + align:start position:0% +and +q 0 and + + align:start position:0% +q 0 and + + + align:start position:0% +q 0 and +q + + align:start position:0% +q + + + align:start position:0% +q +so this is just the formula for taking + + align:start position:0% +so this is just the formula for taking + + + align:start position:0% +so this is just the formula for taking +the derivative of a ratio + + align:start position:0% +the derivative of a ratio + + + align:start position:0% +the derivative of a ratio +and this + + align:start position:0% +and this + + + align:start position:0% +and this +2q here is the derivative of q transpose + + align:start position:0% +2q here is the derivative of q transpose + + + align:start position:0% +2q here is the derivative of q transpose +q with respect to q + + align:start position:0% +q with respect to q + + + align:start position:0% +q with respect to q +and then this is supposed to be zero so + + align:start position:0% +and then this is supposed to be zero so + + + align:start position:0% +and then this is supposed to be zero so +um + + align:start position:0% +um + + + align:start position:0% +um +that means that um + + align:start position:0% + + + + align:start position:0% + +nq is + + align:start position:0% + + + + align:start position:0% + +and this of course is a scalar + + align:start position:0% +and this of course is a scalar + + + align:start position:0% +and this of course is a scalar +from constant + + align:start position:0% +from constant + + + align:start position:0% +from constant +and so so what does this tell us about q + + align:start position:0% + + + + align:start position:0% + +that we multiply some matrix by q and we + + align:start position:0% +that we multiply some matrix by q and we + + + align:start position:0% +that we multiply some matrix by q and we +get out + + align:start position:0% +get out + + + align:start position:0% +get out +some scaled version of q so + + align:start position:0% +some scaled version of q so + + + align:start position:0% +some scaled version of q so +eigenvector right + + align:start position:0% +eigenvector right + + + align:start position:0% +eigenvector right +so + + align:start position:0% + + + + align:start position:0% + +so q is an eigenvector + + align:start position:0% +so q is an eigenvector + + + align:start position:0% +so q is an eigenvector +and now we're trying to maximize this so + + align:start position:0% +and now we're trying to maximize this so + + + align:start position:0% +and now we're trying to maximize this so +we need to know which of the + + align:start position:0% +we need to know which of the + + + align:start position:0% +we need to know which of the +eigenvectors to pick + + align:start position:0% +eigenvectors to pick + + + align:start position:0% +eigenvectors to pick +and it's pretty easy to see that if n + + align:start position:0% +and it's pretty easy to see that if n + + + align:start position:0% +and it's pretty easy to see that if n +is lambda q + + align:start position:0% +is lambda q + + + align:start position:0% +is lambda q +then this ratio over here is going to be + + align:start position:0% +then this ratio over here is going to be + + + align:start position:0% +then this ratio over here is going to be +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +lambda q transpose q + + align:start position:0% +lambda q transpose q + + + align:start position:0% +lambda q transpose q +over q transpose q is lambda + + align:start position:0% +over q transpose q is lambda + + + align:start position:0% +over q transpose q is lambda +and so to maximize it we take pick the + + align:start position:0% +and so to maximize it we take pick the + + + align:start position:0% +and so to maximize it we take pick the +uh + + align:start position:0% +uh + + + align:start position:0% +uh +eigenvalue pick the largest eigenvalue + + align:start position:0% +eigenvalue pick the largest eigenvalue + + + align:start position:0% +eigenvalue pick the largest eigenvalue +right we want to maximize this ratio + + align:start position:0% +right we want to maximize this ratio + + + align:start position:0% +right we want to maximize this ratio +and the way to do it is to pick the pick + + align:start position:0% +and the way to do it is to pick the pick + + + align:start position:0% +and the way to do it is to pick the pick +q to be the + + align:start position:0% +q to be the + + + align:start position:0% +q to be the +eigenvector corresponding to the largest + + align:start position:0% +eigenvector corresponding to the largest + + + align:start position:0% +eigenvector corresponding to the largest +eigenvalue and then this whole thing is + + align:start position:0% +eigenvalue and then this whole thing is + + + align:start position:0% +eigenvalue and then this whole thing is +equal to that eigenvalue + + align:start position:0% +equal to that eigenvalue + + + align:start position:0% +equal to that eigenvalue +so obviously you wouldn't want to pick a + + align:start position:0% +so obviously you wouldn't want to pick a + + + align:start position:0% +so obviously you wouldn't want to pick a +smaller eigenvalue than the maximum one + + align:start position:0% +smaller eigenvalue than the maximum one + + + align:start position:0% +smaller eigenvalue than the maximum one +okay and so that + + align:start position:0% + + + + align:start position:0% + +so the only slight sort of + + align:start position:0% +so the only slight sort of + + + align:start position:0% +so the only slight sort of +tripping point + + align:start position:0% +tripping point + + + align:start position:0% +tripping point +is the fact that there's this constraint + + align:start position:0% +is the fact that there's this constraint + + + align:start position:0% +is the fact that there's this constraint +but you know the constraint is so much + + align:start position:0% +but you know the constraint is so much + + + align:start position:0% +but you know the constraint is so much +easier to handle than the constraint we + + align:start position:0% +easier to handle than the constraint we + + + align:start position:0% +easier to handle than the constraint we +had for constraints we had for + + align:start position:0% +had for constraints we had for + + + align:start position:0% +had for constraints we had for +orthonormal matrices so we can actually + + align:start position:0% +orthonormal matrices so we can actually + + + align:start position:0% +orthonormal matrices so we can actually +do this in a very straightforward way + + align:start position:0% + + + + align:start position:0% + +rally quotient + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +a couple of things that we usually ask + + align:start position:0% +a couple of things that we usually ask + + + align:start position:0% +a couple of things that we usually ask +after we've + + align:start position:0% +after we've + + + align:start position:0% +after we've +quote found the solution one is you know + + align:start position:0% +quote found the solution one is you know + + + align:start position:0% +quote found the solution one is you know +when does it fail + + align:start position:0% +when does it fail + + + align:start position:0% +when does it fail +and the other one is um + + align:start position:0% +and the other one is um + + + align:start position:0% +and the other one is um +uh you know how many how many points do + + align:start position:0% +uh you know how many how many points do + + + align:start position:0% +uh you know how many how many points do +we need how many correspondences + + align:start position:0% +we need how many correspondences + + + align:start position:0% +we need how many correspondences +and so let's start with that so um + + align:start position:0% +and so let's start with that so um + + + align:start position:0% +and so let's start with that so um +in all of these photogrammetric problems + + align:start position:0% +in all of these photogrammetric problems + + + align:start position:0% +in all of these photogrammetric problems +that's an important point + + align:start position:0% + + + + align:start position:0% + +and so well we can approach this from + + align:start position:0% +and so well we can approach this from + + + align:start position:0% +and so well we can approach this from +the point of view of the properties of + + align:start position:0% +the point of view of the properties of + + + align:start position:0% +the point of view of the properties of +this matrix n + + align:start position:0% +this matrix n + + + align:start position:0% +this matrix n +but it's uh + + align:start position:0% +but it's uh + + + align:start position:0% +but it's uh +you know a bit of a bear of a problem to + + align:start position:0% +you know a bit of a bear of a problem to + + + align:start position:0% +you know a bit of a bear of a problem to +uh worry about is n singular is you know + + align:start position:0% +uh worry about is n singular is you know + + + align:start position:0% +uh worry about is n singular is you know +how many eigenvalues are non zero and so + + align:start position:0% +how many eigenvalues are non zero and so + + + align:start position:0% +how many eigenvalues are non zero and so +on let's just do it intuitively + + align:start position:0% +on let's just do it intuitively + + + align:start position:0% +on let's just do it intuitively +so first of all we can say well how many + + align:start position:0% +so first of all we can say well how many + + + align:start position:0% +so first of all we can say well how many +things are we looking for we're looking + + align:start position:0% +things are we looking for we're looking + + + align:start position:0% +things are we looking for we're looking +for six if we're looking for + + align:start position:0% +for six if we're looking for + + + align:start position:0% +for six if we're looking for +translational rotation we're looking for + + align:start position:0% +translational rotation we're looking for + + + align:start position:0% +translational rotation we're looking for +six if we add scaling we might be + + align:start position:0% +six if we add scaling we might be + + + align:start position:0% +six if we add scaling we might be +looking for seven + + align:start position:0% +looking for seven + + + align:start position:0% +looking for seven +so each measurement correspondence + + align:start position:0% +so each measurement correspondence + + + align:start position:0% +so each measurement correspondence +there's a point in 3d + + align:start position:0% +there's a point in 3d + + + align:start position:0% +there's a point in 3d +and a point in 3d that we say are the + + align:start position:0% +and a point in 3d that we say are the + + + align:start position:0% +and a point in 3d that we say are the +same + + align:start position:0% +same + + + align:start position:0% +same +so that's worth three correspondent + + align:start position:0% +so that's worth three correspondent + + + align:start position:0% +so that's worth three correspondent +three + + align:start position:0% +three + + + align:start position:0% +three +constraints right so we're looking for + + align:start position:0% +constraints right so we're looking for + + + align:start position:0% +constraints right so we're looking for +six things so hey we only we only need + + align:start position:0% +six things so hey we only we only need + + + align:start position:0% +six things so hey we only we only need +two correspondences right + + align:start position:0% +two correspondences right + + + align:start position:0% +two correspondences right +that's assuming there's no redundancy in + + align:start position:0% +that's assuming there's no redundancy in + + + align:start position:0% +that's assuming there's no redundancy in +that information well let's start off + + align:start position:0% +that information well let's start off + + + align:start position:0% +that information well let's start off +with one correspondence so here's + + align:start position:0% +with one correspondence so here's + + + align:start position:0% +with one correspondence so here's +here's an object + + align:start position:0% +here's an object + + + align:start position:0% +here's an object +and + + align:start position:0% +and + + + align:start position:0% +and +then we have + + align:start position:0% +then we have + + + align:start position:0% +then we have +a second object and we want to know how + + align:start position:0% +a second object and we want to know how + + + align:start position:0% +a second object and we want to know how +one is rotated relative to the other + + align:start position:0% + + + + align:start position:0% + +and of course we know the duality + + align:start position:0% +and of course we know the duality + + + align:start position:0% +and of course we know the duality +between you know two objects one + + align:start position:0% +between you know two objects one + + + align:start position:0% +between you know two objects one +coordinate system or one object two + + align:start position:0% +coordinate system or one object two + + + align:start position:0% +coordinate system or one object two +coordinate systems so let's do the two + + align:start position:0% +coordinate systems so let's do the two + + + align:start position:0% +coordinate systems so let's do the two +two objects one coordinate system um and + + align:start position:0% +two objects one coordinate system um and + + + align:start position:0% +two objects one coordinate system um and +obviously this isn't gonna do it because + + align:start position:0% +obviously this isn't gonna do it because + + + align:start position:0% +obviously this isn't gonna do it because +you know i can move this thing i can + + align:start position:0% +you know i can move this thing i can + + + align:start position:0% +you know i can move this thing i can +rotate it around that point + + align:start position:0% +rotate it around that point + + + align:start position:0% +rotate it around that point +without changing that correspondence and + + align:start position:0% +without changing that correspondence and + + + align:start position:0% +without changing that correspondence and +also i can rotate it about this axis you + + align:start position:0% +also i can rotate it about this axis you + + + align:start position:0% +also i can rotate it about this axis you +know it's just + + align:start position:0% +know it's just + + + align:start position:0% +know it's just +very little constrainted well + + align:start position:0% +very little constrainted well + + + align:start position:0% +very little constrainted well +uh three + + align:start position:0% +uh three + + + align:start position:0% +uh three +three constraints out of a + + align:start position:0% +three constraints out of a + + + align:start position:0% +three constraints out of a +six-dimensional + + align:start position:0% +six-dimensional + + + align:start position:0% +six-dimensional +uh possibility so that's not good enough + + align:start position:0% +uh possibility so that's not good enough + + + align:start position:0% +uh possibility so that's not good enough +so let's uh pick two suppose that + + align:start position:0% +so let's uh pick two suppose that + + + align:start position:0% +so let's uh pick two suppose that +you know our sort of very rough back of + + align:start position:0% +you know our sort of very rough back of + + + align:start position:0% +you know our sort of very rough back of +the envelope calculation suggested that + + align:start position:0% +the envelope calculation suggested that + + + align:start position:0% +the envelope calculation suggested that +two should be enough because + + align:start position:0% +two should be enough because + + + align:start position:0% +two should be enough because +each of those correspondence gives us + + align:start position:0% +each of those correspondence gives us + + + align:start position:0% +each of those correspondence gives us +three constraints it's very powerful to + + align:start position:0% +three constraints it's very powerful to + + + align:start position:0% +three constraints it's very powerful to +say that you know this point is on top + + align:start position:0% +say that you know this point is on top + + + align:start position:0% +say that you know this point is on top +of that point and so + + align:start position:0% +of that point and so + + + align:start position:0% +of that point and so +we get three out of one correspondence + + align:start position:0% +we get three out of one correspondence + + + align:start position:0% +we get three out of one correspondence +three out of the second correspondence + + align:start position:0% +three out of the second correspondence + + + align:start position:0% +three out of the second correspondence +that makes six we're looking for six + + align:start position:0% +that makes six we're looking for six + + + align:start position:0% +that makes six we're looking for six +degrees of freedom uh maybe that'll do + + align:start position:0% +degrees of freedom uh maybe that'll do + + + align:start position:0% +degrees of freedom uh maybe that'll do +well + + align:start position:0% +well + + + align:start position:0% +well +uh what do you think i mean is that if i + + align:start position:0% +uh what do you think i mean is that if i + + + align:start position:0% +uh what do you think i mean is that if i +tie + + align:start position:0% +tie + + + align:start position:0% +tie +two objects together at two points is + + align:start position:0% +two objects together at two points is + + + align:start position:0% +two objects together at two points is +that enough to rigidly combine them + + align:start position:0% + + + + align:start position:0% + +or is there some degree of freedom left + + align:start position:0% + + + + align:start position:0% + +so it's hard to see because it's in 2d + + align:start position:0% +so it's hard to see because it's in 2d + + + align:start position:0% +so it's hard to see because it's in 2d +but + + align:start position:0% +but + + + align:start position:0% +but +well + + align:start position:0% +well + + + align:start position:0% +well +draw that axis and take one of the + + align:start position:0% +draw that axis and take one of the + + + align:start position:0% +draw that axis and take one of the +objects and rotate it about that axis so + + align:start position:0% +objects and rotate it about that axis so + + + align:start position:0% +objects and rotate it about that axis so +so no that that doesn't work and the + + align:start position:0% +so no that that doesn't work and the + + + align:start position:0% +so no that that doesn't work and the +reason is that when we make the second + + align:start position:0% +reason is that when we make the second + + + align:start position:0% +reason is that when we make the second +measurement we don't get three new + + align:start position:0% +measurement we don't get three new + + + align:start position:0% +measurement we don't get three new +things + + align:start position:0% +things + + + align:start position:0% +things +uh the information's redundant why well + + align:start position:0% +uh the information's redundant why well + + + align:start position:0% +uh the information's redundant why well +because + + align:start position:0% +because + + + align:start position:0% +because +there's the distance between the two + + align:start position:0% +there's the distance between the two + + + align:start position:0% +there's the distance between the two +that + + align:start position:0% +that + + + align:start position:0% +that +is fixed and so + + align:start position:0% +is fixed and so + + + align:start position:0% +is fixed and so +there's um true we have six numbers + + align:start position:0% +there's um true we have six numbers + + + align:start position:0% +there's um true we have six numbers +but there's also one that's not worth + + align:start position:0% +but there's also one that's not worth + + + align:start position:0% +but there's also one that's not worth +anything new + + align:start position:0% +anything new + + + align:start position:0% +anything new +and so + + align:start position:0% +and so + + + align:start position:0% +and so +we only have five constraints so yes + + align:start position:0% +we only have five constraints so yes + + + align:start position:0% +we only have five constraints so yes +we've we've got + + align:start position:0% +we've we've got + + + align:start position:0% +we've we've got +just one left + + align:start position:0% +just one left + + + align:start position:0% +just one left +and it perfectly makes sense + + align:start position:0% +and it perfectly makes sense + + + align:start position:0% +and it perfectly makes sense +we only have one degree of freedom left + + align:start position:0% +we only have one degree of freedom left + + + align:start position:0% +we only have one degree of freedom left +we can rotate about this axis so + + align:start position:0% +we can rotate about this axis so + + + align:start position:0% +we can rotate about this axis so +okay so it takes three + + align:start position:0% +okay so it takes three + + + align:start position:0% +okay so it takes three +it takes three correspondences to work + + align:start position:0% +it takes three correspondences to work + + + align:start position:0% +it takes three correspondences to work +and that and that um + + align:start position:0% +and that and that um + + + align:start position:0% +and that and that um +method that we deprecated at the + + align:start position:0% +method that we deprecated at the + + + align:start position:0% +method that we deprecated at the +beginning + + align:start position:0% +beginning + + + align:start position:0% +beginning +use three correspondences so in that + + align:start position:0% +use three correspondences so in that + + + align:start position:0% +use three correspondences so in that +respect we're not any better + + align:start position:0% +respect we're not any better + + + align:start position:0% +respect we're not any better +we need exactly the same number of + + align:start position:0% +we need exactly the same number of + + + align:start position:0% +we need exactly the same number of +correspondences there's that method that + + align:start position:0% +correspondences there's that method that + + + align:start position:0% +correspondences there's that method that +we pooh-poohed and said wasn't very good + + align:start position:0% +we pooh-poohed and said wasn't very good + + + align:start position:0% +we pooh-poohed and said wasn't very good +so + + align:start position:0% +so + + + align:start position:0% +so +okay + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +um + + align:start position:0% + + + + align:start position:0% + +so one question is um + + align:start position:0% +so one question is um + + + align:start position:0% +so one question is um +and we've come across this before in the + + align:start position:0% +and we've come across this before in the + + + align:start position:0% +and we've come across this before in the +2d world is there some way of + + align:start position:0% +2d world is there some way of + + + align:start position:0% +2d world is there some way of +generalizing the transformation so that + + align:start position:0% +generalizing the transformation so that + + + align:start position:0% +generalizing the transformation so that +it it matches so you know here we with + + align:start position:0% +it it matches so you know here we with + + + align:start position:0% +it it matches so you know here we with +three points we get nine constraints + + align:start position:0% +three points we get nine constraints + + + align:start position:0% +three points we get nine constraints +and of course they're highly redundant + + align:start position:0% +and of course they're highly redundant + + + align:start position:0% +and of course they're highly redundant +because the distances between the points + + align:start position:0% +because the distances between the points + + + align:start position:0% +because the distances between the points +are the same in + + align:start position:0% +are the same in + + + align:start position:0% +are the same in +uh and so um + + align:start position:0% +uh and so um + + + align:start position:0% +uh and so um +is this well with scaling we're up to + + align:start position:0% +is this well with scaling we're up to + + + align:start position:0% +is this well with scaling we're up to +seven so so that's already going the + + align:start position:0% +seven so so that's already going the + + + align:start position:0% +seven so so that's already going the +right direction if we add scaling we + + align:start position:0% +right direction if we add scaling we + + + align:start position:0% +right direction if we add scaling we +need to add + + align:start position:0% +need to add + + + align:start position:0% +need to add +two more + + align:start position:0% +two more + + + align:start position:0% +two more +so that + + align:start position:0% +so that + + + align:start position:0% +so that +we would fully use + + align:start position:0% +we would fully use + + + align:start position:0% +we would fully use +and need + + align:start position:0% +and need + + + align:start position:0% +and need +three correspondences + + align:start position:0% +three correspondences + + + align:start position:0% +three correspondences +so one idea is well + + align:start position:0% +so one idea is well + + + align:start position:0% +so one idea is well +how about the general linear + + align:start position:0% +how about the general linear + + + align:start position:0% +how about the general linear +transformation + + align:start position:0% +transformation + + + align:start position:0% +transformation +and we did this in 2d + + align:start position:0% + + + + align:start position:0% + +and i guess in 2d we ended up with 6 + + align:start position:0% +and i guess in 2d we ended up with 6 + + + align:start position:0% +and i guess in 2d we ended up with 6 +degrees of freedom + + align:start position:0% +degrees of freedom + + + align:start position:0% +degrees of freedom +what is it in 3d + + align:start position:0% +what is it in 3d + + + align:start position:0% +what is it in 3d +so well + + align:start position:0% +so well + + + align:start position:0% +so well +[Applause] + + align:start position:0% + + + + align:start position:0% + +so we could have you know no longer + + align:start position:0% +so we could have you know no longer + + + align:start position:0% +so we could have you know no longer +constrained to orthonormal matrices + + align:start position:0% +constrained to orthonormal matrices + + + align:start position:0% +constrained to orthonormal matrices +and and that actually is a great thing + + align:start position:0% +and and that actually is a great thing + + + align:start position:0% +and and that actually is a great thing +because the orthonormal matrices are the + + align:start position:0% +because the orthonormal matrices are the + + + align:start position:0% +because the orthonormal matrices are the +ones that produce these horrendous uh + + align:start position:0% +ones that produce these horrendous uh + + + align:start position:0% +ones that produce these horrendous uh +problems with the constraints + + align:start position:0% +problems with the constraints + + + align:start position:0% +problems with the constraints +that they are orthonormal + + align:start position:0% +that they are orthonormal + + + align:start position:0% +that they are orthonormal +and oh this this looks just right it's + + align:start position:0% +and oh this this looks just right it's + + + align:start position:0% +and oh this this looks just right it's +got nine numbers in it + + align:start position:0% +got nine numbers in it + + + align:start position:0% +got nine numbers in it +so + + align:start position:0% +so + + + align:start position:0% +so +nine constraints uh + + align:start position:0% +nine constraints uh + + + align:start position:0% +nine constraints uh +from three correspondences + + align:start position:0% +from three correspondences + + + align:start position:0% +from three correspondences +matches to that so it looks like this is + + align:start position:0% +matches to that so it looks like this is + + + align:start position:0% +matches to that so it looks like this is +perhaps the generalization that that we + + align:start position:0% +perhaps the generalization that that we + + + align:start position:0% +perhaps the generalization that that we +need + + align:start position:0% +need + + + align:start position:0% +need +well unfortunately not quite + + align:start position:0% +well unfortunately not quite + + + align:start position:0% +well unfortunately not quite +because we have translation as well + + align:start position:0% + + + + align:start position:0% + +right so the general linear + + align:start position:0% +right so the general linear + + + align:start position:0% +right so the general linear +transformation + + align:start position:0% +transformation + + + align:start position:0% +transformation +has 12 elements in 3d we've had six in + + align:start position:0% +has 12 elements in 3d we've had six in + + + align:start position:0% +has 12 elements in 3d we've had six in +2d + + align:start position:0% +2d + + + align:start position:0% +2d +and so + + align:start position:0% +and so + + + align:start position:0% +and so +we wouldn't + + align:start position:0% +we wouldn't + + + align:start position:0% +we wouldn't +you know there isn't a nice + + align:start position:0% +you know there isn't a nice + + + align:start position:0% +you know there isn't a nice +symmetric argument + + align:start position:0% +symmetric argument + + + align:start position:0% +symmetric argument +that with three correspondences it would + + align:start position:0% +that with three correspondences it would + + + align:start position:0% +that with three correspondences it would +work we would need four correspondences + + align:start position:0% +work we would need four correspondences + + + align:start position:0% +work we would need four correspondences +and that does work and it's very elegant + + align:start position:0% +and that does work and it's very elegant + + + align:start position:0% +and that does work and it's very elegant +and very neat the least squares comes + + align:start position:0% +and very neat the least squares comes + + + align:start position:0% +and very neat the least squares comes +out beautifully because they're none of + + align:start position:0% +out beautifully because they're none of + + + align:start position:0% +out beautifully because they're none of +these annoying constraints like + + align:start position:0% +these annoying constraints like + + + align:start position:0% +these annoying constraints like +determinant of the matrix is one + + align:start position:0% +determinant of the matrix is one + + + align:start position:0% +determinant of the matrix is one +but + + align:start position:0% +but + + + align:start position:0% +but +that's not the transformation that we're + + align:start position:0% +that's not the transformation that we're + + + align:start position:0% +that's not the transformation that we're +dealing with in the real world + + align:start position:0% +dealing with in the real world + + + align:start position:0% +dealing with in the real world +where we have two sensor systems + + align:start position:0% +where we have two sensor systems + + + align:start position:0% +where we have two sensor systems +looking at the world and they're + + align:start position:0% +looking at the world and they're + + + align:start position:0% +looking at the world and they're +typically only dealing with rotation and + + align:start position:0% +typically only dealing with rotation and + + + align:start position:0% +typically only dealing with rotation and +translation maybe scaling but not + + align:start position:0% +translation maybe scaling but not + + + align:start position:0% +translation maybe scaling but not +that full you know this allows skewing + + align:start position:0% +that full you know this allows skewing + + + align:start position:0% +that full you know this allows skewing +of the axes and asymmetric scaling that + + align:start position:0% +of the axes and asymmetric scaling that + + + align:start position:0% +of the axes and asymmetric scaling that +the x-axis is scaled different from the + + align:start position:0% +the x-axis is scaled different from the + + + align:start position:0% +the x-axis is scaled different from the +y-axis + + align:start position:0% +y-axis + + + align:start position:0% +y-axis +and that there's a slant and and so on + + align:start position:0% +and that there's a slant and and so on + + + align:start position:0% +and that there's a slant and and so on +so + + align:start position:0% +so + + + align:start position:0% +so +okay + + align:start position:0% +okay + + + align:start position:0% +okay +um + + align:start position:0% +um + + + align:start position:0% +um +so back to our analysis of this method + + align:start position:0% +so back to our analysis of this method + + + align:start position:0% +so back to our analysis of this method +we've said something about how many + + align:start position:0% +we've said something about how many + + + align:start position:0% +we've said something about how many +correspondences we need we also should + + align:start position:0% +correspondences we need we also should + + + align:start position:0% +correspondences we need we also should +sort of so one one way to fail is to not + + align:start position:0% +sort of so one one way to fail is to not + + + align:start position:0% +sort of so one one way to fail is to not +have enough correspondences and it's + + align:start position:0% +have enough correspondences and it's + + + align:start position:0% +have enough correspondences and it's +if you have only two correspondences + + align:start position:0% +if you have only two correspondences + + + align:start position:0% +if you have only two correspondences +that matrix n will be singular + + align:start position:0% + + + + align:start position:0% + +which isn't enough to make the method + + align:start position:0% +which isn't enough to make the method + + + align:start position:0% +which isn't enough to make the method +not work but uh it will it will have uh + + align:start position:0% +not work but uh it will it will have uh + + + align:start position:0% +not work but uh it will it will have uh +more than one eigenvalue that zero + + align:start position:0% +more than one eigenvalue that zero + + + align:start position:0% +more than one eigenvalue that zero +and and that's + + align:start position:0% +and and that's + + + align:start position:0% +and and that's +a way to formalize our hand waving + + align:start position:0% +a way to formalize our hand waving + + + align:start position:0% +a way to formalize our hand waving +argument but it's + + align:start position:0% +argument but it's + + + align:start position:0% +argument but it's +kind of messy so didn't want to do that + + align:start position:0% +kind of messy so didn't want to do that + + + align:start position:0% +kind of messy so didn't want to do that +but there is another case that we want + + align:start position:0% +but there is another case that we want + + + align:start position:0% +but there is another case that we want +to look at that's actually kind of + + align:start position:0% +to look at that's actually kind of + + + align:start position:0% +to look at that's actually kind of +interesting + + align:start position:0% +interesting + + + align:start position:0% +interesting +so + + align:start position:0% +so + + + align:start position:0% +so +how do we find the eigenvalues + + align:start position:0% +how do we find the eigenvalues + + + align:start position:0% +how do we find the eigenvalues +well um + + align:start position:0% +well um + + + align:start position:0% +well um +you know we use matlab + + align:start position:0% +you know we use matlab + + + align:start position:0% +you know we use matlab +or more seriously + + align:start position:0% +or more seriously + + + align:start position:0% +or more seriously +uh we need to solve this uh + + align:start position:0% +uh we need to solve this uh + + + align:start position:0% +uh we need to solve this uh +characteristic equation so which is + + align:start position:0% +characteristic equation so which is + + + align:start position:0% +characteristic equation so which is +obtained from that matrix n so that's uh + + align:start position:0% +obtained from that matrix n so that's uh + + + align:start position:0% +obtained from that matrix n so that's uh +that's the equation that says + + align:start position:0% +that's the equation that says + + + align:start position:0% +that's the equation that says +determinant of n + + align:start position:0% +determinant of n + + + align:start position:0% +determinant of n +minus lambda i is zero + + align:start position:0% +minus lambda i is zero + + + align:start position:0% +minus lambda i is zero +so that's the determinant of a four by + + align:start position:0% +so that's the determinant of a four by + + + align:start position:0% +so that's the determinant of a four by +four matrix that has minus lambdas down + + align:start position:0% +four matrix that has minus lambdas down + + + align:start position:0% +four matrix that has minus lambdas down +the diagonal + + align:start position:0% +the diagonal + + + align:start position:0% +the diagonal +subtracted out the diagonal + + align:start position:0% +subtracted out the diagonal + + + align:start position:0% +subtracted out the diagonal +and when we take the determinant we get + + align:start position:0% +and when we take the determinant we get + + + align:start position:0% +and when we take the determinant we get +up to fourth order combinations of + + align:start position:0% +up to fourth order combinations of + + + align:start position:0% +up to fourth order combinations of +lambda so it's going to look like this + + align:start position:0% +lambda so it's going to look like this + + + align:start position:0% +lambda so it's going to look like this +now our matrix n is a particular matrix + + align:start position:0% +now our matrix n is a particular matrix + + + align:start position:0% +now our matrix n is a particular matrix +that was obtained this way + + align:start position:0% +that was obtained this way + + + align:start position:0% +that was obtained this way +and so + + align:start position:0% +and so + + + align:start position:0% +and so +actually we can say more about this + + align:start position:0% +actually we can say more about this + + + align:start position:0% +actually we can say more about this +and i already mentioned this last time + + align:start position:0% +and i already mentioned this last time + + + align:start position:0% +and i already mentioned this last time +it's not easy to show but + + align:start position:0% +it's not easy to show but + + + align:start position:0% +it's not easy to show but +c3 is the trace of the matrix + + align:start position:0% +c3 is the trace of the matrix + + + align:start position:0% +c3 is the trace of the matrix +that happens to be zero well it's easy + + align:start position:0% +that happens to be zero well it's easy + + + align:start position:0% +that happens to be zero well it's easy +to show it's a trace of the matrix it's + + align:start position:0% +to show it's a trace of the matrix it's + + + align:start position:0% +to show it's a trace of the matrix it's +not easy to show that it's zero so + + align:start position:0% +not easy to show that it's zero so + + + align:start position:0% +not easy to show that it's zero so +anyway it's zero which makes this + + align:start position:0% +anyway it's zero which makes this + + + align:start position:0% +anyway it's zero which makes this +equation easier to solve + + align:start position:0% +equation easier to solve + + + align:start position:0% +equation easier to solve +in fact usually the first step in + + align:start position:0% +in fact usually the first step in + + + align:start position:0% +in fact usually the first step in +solving a fourth order equation is to + + align:start position:0% +solving a fourth order equation is to + + + align:start position:0% +solving a fourth order equation is to +eliminate the third order term well it's + + align:start position:0% +eliminate the third order term well it's + + + align:start position:0% +eliminate the third order term well it's +already happened so we're kind of ahead + + align:start position:0% +already happened so we're kind of ahead + + + align:start position:0% +already happened so we're kind of ahead +of the game + + align:start position:0% +of the game + + + align:start position:0% +of the game +what about the others + + align:start position:0% + + + + align:start position:0% + +so this is the trace of another matrix + + align:start position:0% + + + + align:start position:0% + +so these others aren't 0 so that's + + align:start position:0% +so these others aren't 0 so that's + + + align:start position:0% +so these others aren't 0 so that's +so what is this matrix m well the matrix + + align:start position:0% +so what is this matrix m well the matrix + + + align:start position:0% +so what is this matrix m well the matrix +m is where we actually + + align:start position:0% +m is where we actually + + + align:start position:0% +m is where we actually +started with + + align:start position:0% +started with + + + align:start position:0% +started with +this is what you'd compute when you got + + align:start position:0% +this is what you'd compute when you got + + + align:start position:0% +this is what you'd compute when you got +the correspondences + + align:start position:0% + + + + align:start position:0% + +what's that that's a dyadic product so + + align:start position:0% +what's that that's a dyadic product so + + + align:start position:0% +what's that that's a dyadic product so +we take the vector in the left-hand + + align:start position:0% +we take the vector in the left-hand + + + align:start position:0% +we take the vector in the left-hand +coordinate system and multiplied by the + + align:start position:0% +coordinate system and multiplied by the + + + align:start position:0% +coordinate system and multiplied by the +vector in the right-hand coordinate + + align:start position:0% +vector in the right-hand coordinate + + + align:start position:0% +vector in the right-hand coordinate +system but rather than + + align:start position:0% +system but rather than + + + align:start position:0% +system but rather than +the transpose of the first times the + + align:start position:0% +the transpose of the first times the + + + align:start position:0% +the transpose of the first times the +second which gives us a dot product + + align:start position:0% +second which gives us a dot product + + + align:start position:0% +second which gives us a dot product +we do this and you've seen that so + + align:start position:0% +we do this and you've seen that so + + + align:start position:0% +we do this and you've seen that so +that's a three by three matrix we just + + align:start position:0% +that's a three by three matrix we just + + + align:start position:0% +that's a three by three matrix we just +step through the data + + align:start position:0% +step through the data + + + align:start position:0% +step through the data +correspondence by correspondence and we + + align:start position:0% +correspondence by correspondence and we + + + align:start position:0% +correspondence by correspondence and we +compute this diatic product and add it + + align:start position:0% +compute this diatic product and add it + + + align:start position:0% +compute this diatic product and add it +into a total and we get that matrix m + + align:start position:0% +into a total and we get that matrix m + + + align:start position:0% +into a total and we get that matrix m +which is of course 3 by 3. + + align:start position:0% +which is of course 3 by 3. + + + align:start position:0% +which is of course 3 by 3. +and it and it turns out that the four by + + align:start position:0% +and it and it turns out that the four by + + + align:start position:0% +and it and it turns out that the four by +four matrix n + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% +uh + + + align:start position:0% +uh +has + + align:start position:0% +has + + + align:start position:0% +has +terms + + align:start position:0% +terms + + + align:start position:0% +terms +that are com + + align:start position:0% +that are com + + + align:start position:0% +that are com +can be computed + + align:start position:0% +can be computed + + + align:start position:0% +can be computed +from this matrix so that's actually the + + align:start position:0% +from this matrix so that's actually the + + + align:start position:0% +from this matrix so that's actually the +most efficient way of getting n you just + + align:start position:0% +most efficient way of getting n you just + + + align:start position:0% +most efficient way of getting n you just +step through all of your data and + + align:start position:0% +step through all of your data and + + + align:start position:0% +step through all of your data and +compute + + align:start position:0% +compute + + + align:start position:0% +compute +m and then at the end + + align:start position:0% +m and then at the end + + + align:start position:0% +m and then at the end +you + + align:start position:0% +you + + + align:start position:0% +you +compute n from it + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +um + + align:start position:0% +um + + + align:start position:0% +um +next thing + + align:start position:0% +next thing + + + align:start position:0% +next thing +suppose that the determinant of m is + + align:start position:0% +suppose that the determinant of m is + + + align:start position:0% +suppose that the determinant of m is +zero + + align:start position:0% +zero + + + align:start position:0% +zero +suppose that m is singular + + align:start position:0% +suppose that m is singular + + + align:start position:0% +suppose that m is singular +well that's + + align:start position:0% +well that's + + + align:start position:0% +well that's +pretty useful + + align:start position:0% +pretty useful + + + align:start position:0% +pretty useful +because that means that c1 is zero + + align:start position:0% +because that means that c1 is zero + + + align:start position:0% +because that means that c1 is zero +and then we can all solve this equation + + align:start position:0% +and then we can all solve this equation + + + align:start position:0% +and then we can all solve this equation +without needing to go to any special + + align:start position:0% +without needing to go to any special + + + align:start position:0% +without needing to go to any special +textbook or something because then we've + + align:start position:0% +textbook or something because then we've + + + align:start position:0% +textbook or something because then we've +got lambda to the fourth plus + + align:start position:0% +got lambda to the fourth plus + + + align:start position:0% +got lambda to the fourth plus +c2 lambda squared plus c0 is zero + + align:start position:0% +c2 lambda squared plus c0 is zero + + + align:start position:0% +c2 lambda squared plus c0 is zero +right in that case it reduces to that + + align:start position:0% +right in that case it reduces to that + + + align:start position:0% +right in that case it reduces to that +problem and we use what equation to + + align:start position:0% +problem and we use what equation to + + + align:start position:0% +problem and we use what equation to +solve that + + align:start position:0% + + + + align:start position:0% + +so it seems to have lambda to the fourth + + align:start position:0% +so it seems to have lambda to the fourth + + + align:start position:0% +so it seems to have lambda to the fourth +in it which means we should use ferrari + + align:start position:0% +in it which means we should use ferrari + + + align:start position:0% +in it which means we should use ferrari +or cardano + + align:start position:0% +or cardano + + + align:start position:0% +or cardano +but um + + align:start position:0% +but um + + + align:start position:0% +but um +of course it's quadratic in lambda + + align:start position:0% +of course it's quadratic in lambda + + + align:start position:0% +of course it's quadratic in lambda +squared right so + + align:start position:0% +squared right so + + + align:start position:0% +squared right so +so we just apply the quadratic so it's + + align:start position:0% +so we just apply the quadratic so it's + + + align:start position:0% +so we just apply the quadratic so it's +particularly easy case + + align:start position:0% +particularly easy case + + + align:start position:0% +particularly easy case +and so + + align:start position:0% + + + + align:start position:0% + +you might wonder well who cares that's a + + align:start position:0% +you might wonder well who cares that's a + + + align:start position:0% +you might wonder well who cares that's a +special case well it turns out it's a + + align:start position:0% +special case well it turns out it's a + + + align:start position:0% +special case well it turns out it's a +it's a particular + + align:start position:0% +it's a particular + + + align:start position:0% +it's a particular +case that's interesting from a geometric + + align:start position:0% +case that's interesting from a geometric + + + align:start position:0% +case that's interesting from a geometric +point of view it's a + + align:start position:0% +point of view it's a + + + align:start position:0% +point of view it's a +it has to do with a distribution of the + + align:start position:0% +it has to do with a distribution of the + + + align:start position:0% +it has to do with a distribution of the +points + + align:start position:0% +points + + + align:start position:0% +points +and so + + align:start position:0% +and so + + + align:start position:0% +and so +um this matrix n + + align:start position:0% +um this matrix n + + + align:start position:0% +um this matrix n +can have some zero eigen values which + + align:start position:0% +can have some zero eigen values which + + + align:start position:0% +can have some zero eigen values which +are potentially problematic + + align:start position:0% +are potentially problematic + + + align:start position:0% +are potentially problematic +and when does that occur well uh one is + + align:start position:0% +and when does that occur well uh one is + + + align:start position:0% +and when does that occur well uh one is +when points are coplanar + + align:start position:0% + + + + align:start position:0% + +right so so far we've talked about + + align:start position:0% +right so so far we've talked about + + + align:start position:0% +right so so far we've talked about +you know clouds of points + + align:start position:0% +you know clouds of points + + + align:start position:0% +you know clouds of points +like the spikes on a sea urchin + + align:start position:0% +like the spikes on a sea urchin + + + align:start position:0% +like the spikes on a sea urchin +and we're matching two of these we're + + align:start position:0% +and we're matching two of these we're + + + align:start position:0% +and we're matching two of these we're +rotating one in alignment with the other + + align:start position:0% +rotating one in alignment with the other + + + align:start position:0% +rotating one in alignment with the other +but + + align:start position:0% +but + + + align:start position:0% +but +this applies equally well if + + align:start position:0% +this applies equally well if + + + align:start position:0% +this applies equally well if +all of those points are + + align:start position:0% +all of those points are + + + align:start position:0% +all of those points are +in a plane and so what what happens then + + align:start position:0% +in a plane and so what what happens then + + + align:start position:0% +in a plane and so what what happens then +well + + align:start position:0% +well + + + align:start position:0% +well +if there's a + + align:start position:0% +if there's a + + + align:start position:0% +if there's a +plane + + align:start position:0% +plane + + + align:start position:0% +plane +then + + align:start position:0% + + + + align:start position:0% + +all of our points + + align:start position:0% + + + + align:start position:0% + +in that plane and we can draw a + + align:start position:0% +in that plane and we can draw a + + + align:start position:0% +in that plane and we can draw a +unit normal to the plane + + align:start position:0% +unit normal to the plane + + + align:start position:0% +unit normal to the plane +and then the dot product + + align:start position:0% +and then the dot product + + + align:start position:0% +and then the dot product +has to be zero so + + align:start position:0% +has to be zero so + + + align:start position:0% +has to be zero so +let's suppose that + + align:start position:0% + + + + align:start position:0% + +let's suppose all the right hand points + + align:start position:0% +let's suppose all the right hand points + + + align:start position:0% +let's suppose all the right hand points +are in a plane now with + + align:start position:0% +are in a plane now with + + + align:start position:0% +are in a plane now with +our measurement error that implies that + + align:start position:0% +our measurement error that implies that + + + align:start position:0% +our measurement error that implies that +the left-hand points also in a plane but + + align:start position:0% +the left-hand points also in a plane but + + + align:start position:0% +the left-hand points also in a plane but +we we may not + + align:start position:0% +we we may not + + + align:start position:0% +we we may not +need to make that restriction there + + align:start position:0% +need to make that restriction there + + + align:start position:0% +need to make that restriction there +might be measurement error and the + + align:start position:0% +might be measurement error and the + + + align:start position:0% +might be measurement error and the +others might not be exactly in the plan + + align:start position:0% +others might not be exactly in the plan + + + align:start position:0% +others might not be exactly in the plan +right + + align:start position:0% +right + + + align:start position:0% +right +so what i've done here is + + align:start position:0% +so what i've done here is + + + align:start position:0% +so what i've done here is +i've drawn the centroid so i've already + + align:start position:0% +i've drawn the centroid so i've already + + + align:start position:0% +i've drawn the centroid so i've already +moved everything to the centroid and + + align:start position:0% +moved everything to the centroid and + + + align:start position:0% +moved everything to the centroid and +therefore i can write the equation of + + align:start position:0% +therefore i can write the equation of + + + align:start position:0% +therefore i can write the equation of +the plane in this simple form + + align:start position:0% +the plane in this simple form + + + align:start position:0% +the plane in this simple form +uh the dot product you know the + + align:start position:0% +uh the dot product you know the + + + align:start position:0% +uh the dot product you know the +component of any one of these vectors + + align:start position:0% +component of any one of these vectors + + + align:start position:0% +component of any one of these vectors +in this direction is zero that that's + + align:start position:0% +in this direction is zero that that's + + + align:start position:0% +in this direction is zero that that's +the definition of the plane + + align:start position:0% +the definition of the plane + + + align:start position:0% +the definition of the plane +okay well then + + align:start position:0% +okay well then + + + align:start position:0% +okay well then +that's the same as r i transpose + + align:start position:0% + + + + align:start position:0% + +and then i can go to m and + + align:start position:0% +and then i can go to m and + + + align:start position:0% +and then i can go to m and +hat is + + align:start position:0% + + + + align:start position:0% + +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +if the points are coplanar then we do + + align:start position:0% +if the points are coplanar then we do + + + align:start position:0% +if the points are coplanar then we do +have the determinant of m is zero and + + align:start position:0% +have the determinant of m is zero and + + + align:start position:0% +have the determinant of m is zero and +then that problem is particularly uh + + align:start position:0% +then that problem is particularly uh + + + align:start position:0% +then that problem is particularly uh +easy to solve + + align:start position:0% +easy to solve + + + align:start position:0% +easy to solve +now i haven't shown it the other way + + align:start position:0% +now i haven't shown it the other way + + + align:start position:0% +now i haven't shown it the other way +around which is which i should which is + + align:start position:0% +around which is which i should which is + + + align:start position:0% +around which is which i should which is +that if determinant of m is zero the + + align:start position:0% +that if determinant of m is zero the + + + align:start position:0% +that if determinant of m is zero the +points are coplanar but i think you can + + align:start position:0% +points are coplanar but i think you can + + + align:start position:0% +points are coplanar but i think you can +see how to do that without too much + + align:start position:0% +see how to do that without too much + + + align:start position:0% +see how to do that without too much +trouble + + align:start position:0% +trouble + + + align:start position:0% +trouble +now in that case actually we can + + align:start position:0% +now in that case actually we can + + + align:start position:0% +now in that case actually we can +solve the problem more simply + + align:start position:0% +solve the problem more simply + + + align:start position:0% +solve the problem more simply +suppose that + + align:start position:0% +suppose that + + + align:start position:0% +suppose that +things are nice and both are + + align:start position:0% +things are nice and both are + + + align:start position:0% +things are nice and both are +coplanar both the left-hand corner + + align:start position:0% +coplanar both the left-hand corner + + + align:start position:0% +coplanar both the left-hand corner +left-hand cloud of points and the + + align:start position:0% +left-hand cloud of points and the + + + align:start position:0% +left-hand cloud of points and the +right-hand cloud of points + + align:start position:0% +right-hand cloud of points + + + align:start position:0% +right-hand cloud of points +so i can draw these two planes so here's + + align:start position:0% +so i can draw these two planes so here's + + + align:start position:0% +so i can draw these two planes so here's +one plane so all of the points on the in + + align:start position:0% +one plane so all of the points on the in + + + align:start position:0% +one plane so all of the points on the in +the left-hand coordinate system of one + + align:start position:0% +the left-hand coordinate system of one + + + align:start position:0% +the left-hand coordinate system of one +plane all of the right-hand ones are in + + align:start position:0% +plane all of the right-hand ones are in + + + align:start position:0% +plane all of the right-hand ones are in +this other plane + + align:start position:0% + + + + align:start position:0% + +not not particularly good drawing well + + align:start position:0% +not not particularly good drawing well + + + align:start position:0% +not not particularly good drawing well +two planes so + + align:start position:0% +two planes so + + + align:start position:0% +two planes so +all of uh left + + align:start position:0% +all of uh left + + + align:start position:0% +all of uh left +point cloud + + align:start position:0% + + + + align:start position:0% + +uh right point cloud + + align:start position:0% + + + + align:start position:0% + +so i'm gonna + + align:start position:0% +so i'm gonna + + + align:start position:0% +so i'm gonna +then then i can decompose the problem + + align:start position:0% +then then i can decompose the problem + + + align:start position:0% +then then i can decompose the problem +into two parts two steps the one step is + + align:start position:0% +into two parts two steps the one step is + + + align:start position:0% +into two parts two steps the one step is +um + + align:start position:0% +um + + + align:start position:0% +um +rotate the one plane so it lies on top + + align:start position:0% +rotate the one plane so it lies on top + + + align:start position:0% +rotate the one plane so it lies on top +of the other plane + + align:start position:0% +of the other plane + + + align:start position:0% +of the other plane +and then an in-plane rotation and i'm + + align:start position:0% +and then an in-plane rotation and i'm + + + align:start position:0% +and then an in-plane rotation and i'm +done so the only two things i can + + align:start position:0% +done so the only two things i can + + + align:start position:0% +done so the only two things i can +decompose the + + align:start position:0% +decompose the + + + align:start position:0% +decompose the +full 3d rotation into two very simple + + align:start position:0% +full 3d rotation into two very simple + + + align:start position:0% +full 3d rotation into two very simple +rotations now to do that i'd need to + + align:start position:0% +rotations now to do that i'd need to + + + align:start position:0% +rotations now to do that i'd need to +find this angle + + align:start position:0% +find this angle + + + align:start position:0% +find this angle +and i need to find this axis + + align:start position:0% + + + + align:start position:0% + +and the axis is parallel to + + align:start position:0% +and the axis is parallel to + + + align:start position:0% +and the axis is parallel to +n1 cross n2 + + align:start position:0% +n1 cross n2 + + + align:start position:0% +n1 cross n2 +right if we have two planes that have + + align:start position:0% +right if we have two planes that have + + + align:start position:0% +right if we have two planes that have +normals in one and n2 + + align:start position:0% +normals in one and n2 + + + align:start position:0% +normals in one and n2 +they intersect in a line which is + + align:start position:0% +they intersect in a line which is + + + align:start position:0% +they intersect in a line which is +parallel to n1 cross n2 + + align:start position:0% +parallel to n1 cross n2 + + + align:start position:0% +parallel to n1 cross n2 +and the angles of course i can get + + align:start position:0% +and the angles of course i can get + + + align:start position:0% +and the angles of course i can get +very easily also + + align:start position:0% + + + + align:start position:0% + +i take the dot product + + align:start position:0% +i take the dot product + + + align:start position:0% +i take the dot product +that gives me the cosine + + align:start position:0% +that gives me the cosine + + + align:start position:0% +that gives me the cosine +i take the cross product + + align:start position:0% +i take the cross product + + + align:start position:0% +i take the cross product +and the magnitude of that gives me + + align:start position:0% +and the magnitude of that gives me + + + align:start position:0% +and the magnitude of that gives me +the sine and then i use a tan too + + align:start position:0% + + + + align:start position:0% + +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +i've got the axis i've got the angle so + + align:start position:0% +i've got the axis i've got the angle so + + + align:start position:0% +i've got the axis i've got the angle so +i can construct the quaternion + + align:start position:0% + + + + align:start position:0% + +and then i rotate all of the points in + + align:start position:0% +and then i rotate all of the points in + + + align:start position:0% +and then i rotate all of the points in +one of the coordinate systems + + align:start position:0% +one of the coordinate systems + + + align:start position:0% +one of the coordinate systems +and now the two planes on top of each + + align:start position:0% +and now the two planes on top of each + + + align:start position:0% +and now the two planes on top of each +other and now i've just got to take the + + align:start position:0% +other and now i've just got to take the + + + align:start position:0% +other and now i've just got to take the +rotation in that plane + + align:start position:0% +rotation in that plane + + + align:start position:0% +rotation in that plane +uh so that um these points align so + + align:start position:0% +uh so that um these points align so + + + align:start position:0% +uh so that um these points align so +that's a least squares 2d problem + + align:start position:0% +that's a least squares 2d problem + + + align:start position:0% +that's a least squares 2d problem +but like you've solved in homework + + align:start position:0% +but like you've solved in homework + + + align:start position:0% +but like you've solved in homework +problems + + align:start position:0% +problems + + + align:start position:0% +problems +of course it's in a plane that's + + align:start position:0% +of course it's in a plane that's + + + align:start position:0% +of course it's in a plane that's +somewhere in 3d but + + align:start position:0% +somewhere in 3d but + + + align:start position:0% +somewhere in 3d but +pre pretty straightforward anyway so so + + align:start position:0% +pre pretty straightforward anyway so so + + + align:start position:0% +pre pretty straightforward anyway so so +that's interesting that you know the + + align:start position:0% +that's interesting that you know the + + + align:start position:0% +that's interesting that you know the +special cases where + + align:start position:0% +special cases where + + + align:start position:0% +special cases where +things change in terms of the difficulty + + align:start position:0% +things change in terms of the difficulty + + + align:start position:0% +things change in terms of the difficulty +of solution also correspond to some + + align:start position:0% +of solution also correspond to some + + + align:start position:0% +of solution also correspond to some +things that are physically + + align:start position:0% +things that are physically + + + align:start position:0% +things that are physically +relevant so + + align:start position:0% +relevant so + + + align:start position:0% +relevant so +okay + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +let's see + + align:start position:0% + + + + align:start position:0% + +um where to go next i don't want to go + + align:start position:0% +um where to go next i don't want to go + + + align:start position:0% +um where to go next i don't want to go +on to relative orientation too quickly i + + align:start position:0% +on to relative orientation too quickly i + + + align:start position:0% +on to relative orientation too quickly i +want this to + + align:start position:0% +want this to + + + align:start position:0% +want this to +sink in + + align:start position:0% +sink in + + + align:start position:0% +sink in +because this is like a triumph we've got + + align:start position:0% +because this is like a triumph we've got + + + align:start position:0% +because this is like a triumph we've got +a close form solution and sadly + + align:start position:0% +a close form solution and sadly + + + align:start position:0% +a close form solution and sadly +so far there isn't one for relative + + align:start position:0% +so far there isn't one for relative + + + align:start position:0% +so far there isn't one for relative +orientation but we use a lot of the same + + align:start position:0% +orientation but we use a lot of the same + + + align:start position:0% +orientation but we use a lot of the same +tools the representation for rotation + + align:start position:0% +tools the representation for rotation + + + align:start position:0% +tools the representation for rotation +and so on but i want to look at some + + align:start position:0% +and so on but i want to look at some + + + align:start position:0% +and so on but i want to look at some +other aspects one of them is you know + + align:start position:0% +other aspects one of them is you know + + + align:start position:0% +other aspects one of them is you know +least squares everything we've done in + + align:start position:0% +least squares everything we've done in + + + align:start position:0% +least squares everything we've done in +this course is least squares and if you + + align:start position:0% +this course is least squares and if you + + + align:start position:0% +this course is least squares and if you +talk to your more sophisticated friends + + align:start position:0% +talk to your more sophisticated friends + + + align:start position:0% +talk to your more sophisticated friends +they'll say oh that's useless because + + align:start position:0% +they'll say oh that's useless because + + + align:start position:0% +they'll say oh that's useless because +not robust + + align:start position:0% +not robust + + + align:start position:0% +not robust +and what does that mean well it means + + align:start position:0% +and what does that mean well it means + + + align:start position:0% +and what does that mean well it means +that if you have a + + align:start position:0% +that if you have a + + + align:start position:0% +that if you have a +nice noise + + align:start position:0% +nice noise + + + align:start position:0% +nice noise +these squares is the way to go + + align:start position:0% +these squares is the way to go + + + align:start position:0% +these squares is the way to go +by nice noise we mean something that has + + align:start position:0% +by nice noise we mean something that has + + + align:start position:0% +by nice noise we mean something that has +a reasonable distribution like gaussian + + align:start position:0% +a reasonable distribution like gaussian + + + align:start position:0% +a reasonable distribution like gaussian +and + + align:start position:0% +and + + + align:start position:0% +and +the problem + + align:start position:0% +the problem + + + align:start position:0% +the problem +we face in practice sometimes is that + + align:start position:0% +we face in practice sometimes is that + + + align:start position:0% +we face in practice sometimes is that +a lot of the measurements sort of follow + + align:start position:0% +a lot of the measurements sort of follow + + + align:start position:0% +a lot of the measurements sort of follow +a gaussian + + align:start position:0% +a gaussian + + + align:start position:0% +a gaussian +distribution but every now and then you + + align:start position:0% +distribution but every now and then you + + + align:start position:0% +distribution but every now and then you +get something that's completely wacko + + align:start position:0% +get something that's completely wacko + + + align:start position:0% +get something that's completely wacko +and so what what do you do with that so + + align:start position:0% +and so what what do you do with that so + + + align:start position:0% +and so what what do you do with that so +how do we deal with outliers + + align:start position:0% +how do we deal with outliers + + + align:start position:0% +how do we deal with outliers +now you can formulate + + align:start position:0% +now you can formulate + + + align:start position:0% +now you can formulate +a new optimization problem + + align:start position:0% +a new optimization problem + + + align:start position:0% +a new optimization problem +that uses something other than square of + + align:start position:0% +that uses something other than square of + + + align:start position:0% +that uses something other than square of +error + + align:start position:0% +error + + + align:start position:0% +error +for example absolute value of error but + + align:start position:0% +for example absolute value of error but + + + align:start position:0% +for example absolute value of error but +it no longer has a closed form solution + + align:start position:0% +it no longer has a closed form solution + + + align:start position:0% +it no longer has a closed form solution +and so there's a trade-off obviously if + + align:start position:0% +and so there's a trade-off obviously if + + + align:start position:0% +and so there's a trade-off obviously if +you don't have a closed-form solution it + + align:start position:0% +you don't have a closed-form solution it + + + align:start position:0% +you don't have a closed-form solution it +might be more work to compute that's + + align:start position:0% +might be more work to compute that's + + + align:start position:0% +might be more work to compute that's +often not an issue + + align:start position:0% +often not an issue + + + align:start position:0% +often not an issue +but it also makes it very hard to say + + align:start position:0% +but it also makes it very hard to say + + + align:start position:0% +but it also makes it very hard to say +anything in general about it like how + + align:start position:0% +anything in general about it like how + + + align:start position:0% +anything in general about it like how +does it vary with the parameters and so + + align:start position:0% +does it vary with the parameters and so + + + align:start position:0% +does it vary with the parameters and so +on you know if the only way you get the + + align:start position:0% +on you know if the only way you get the + + + align:start position:0% +on you know if the only way you get the +answer is to crunch the numbers uh then + + align:start position:0% +answer is to crunch the numbers uh then + + + align:start position:0% +answer is to crunch the numbers uh then +you don't have that uh + + align:start position:0% +you don't have that uh + + + align:start position:0% +you don't have that uh +pleasant experience of a general formula + + align:start position:0% +pleasant experience of a general formula + + + align:start position:0% +pleasant experience of a general formula +that says oh it's going to vary with + + align:start position:0% +that says oh it's going to vary with + + + align:start position:0% +that says oh it's going to vary with +linearly with frequency or something + + align:start position:0% +linearly with frequency or something + + + align:start position:0% +linearly with frequency or something +like that + + align:start position:0% +like that + + + align:start position:0% +like that +so that's one disadvantage of + + align:start position:0% +so that's one disadvantage of + + + align:start position:0% +so that's one disadvantage of +departing from this least squares method + + align:start position:0% +departing from this least squares method + + + align:start position:0% +departing from this least squares method +so suppose that we have a 2d problem and + + align:start position:0% +so suppose that we have a 2d problem and + + + align:start position:0% +so suppose that we have a 2d problem and +we're just doing a + + align:start position:0% +we're just doing a + + + align:start position:0% +we're just doing a +line fit + + align:start position:0% +line fit + + + align:start position:0% +line fit +so we have you know + + align:start position:0% +so we have you know + + + align:start position:0% +so we have you know +there's our + + align:start position:0% +there's our + + + align:start position:0% +there's our +least squares line but now suppose that + + align:start position:0% +least squares line but now suppose that + + + align:start position:0% +least squares line but now suppose that +there's some data point that's just + + align:start position:0% +there's some data point that's just + + + align:start position:0% +there's some data point that's just +completely waco well that has a huge + + align:start position:0% +completely waco well that has a huge + + + align:start position:0% +completely waco well that has a huge +square of uh error and so it's going to + + align:start position:0% +square of uh error and so it's going to + + + align:start position:0% +square of uh error and so it's going to +pull your solution dramatically in that + + align:start position:0% +pull your solution dramatically in that + + + align:start position:0% +pull your solution dramatically in that +direction + + align:start position:0% +direction + + + align:start position:0% +direction +so that's kind of the intuition and it'd + + align:start position:0% +so that's kind of the intuition and it'd + + + align:start position:0% +so that's kind of the intuition and it'd +be slightly better if it was absolute + + align:start position:0% +be slightly better if it was absolute + + + align:start position:0% +be slightly better if it was absolute +value of error because then it wouldn't + + align:start position:0% +value of error because then it wouldn't + + + align:start position:0% +value of error because then it wouldn't +pull quite as hard + + align:start position:0% +pull quite as hard + + + align:start position:0% +pull quite as hard +but it would be even better if you said + + align:start position:0% +but it would be even better if you said + + + align:start position:0% +but it would be even better if you said +oh that point's just crazy forget it so + + align:start position:0% +oh that point's just crazy forget it so + + + align:start position:0% +oh that point's just crazy forget it so +so you know and they're different + + align:start position:0% +so you know and they're different + + + align:start position:0% +so you know and they're different +approaches to this so there's there's a + + align:start position:0% +approaches to this so there's there's a + + + align:start position:0% +approaches to this so there's there's a +sort of question of uh + + align:start position:0% +sort of question of uh + + + align:start position:0% +sort of question of uh +robustly dealing with with outliers + + align:start position:0% +robustly dealing with with outliers + + + align:start position:0% +robustly dealing with with outliers +now uh now it actually goes further than + + align:start position:0% +now uh now it actually goes further than + + + align:start position:0% +now uh now it actually goes further than +that that you can show that there are + + align:start position:0% +that that you can show that there are + + + align:start position:0% +that that you can show that there are +certain problems + + align:start position:0% +certain problems + + + align:start position:0% +certain problems +where if the noise is gaussian then + + align:start position:0% +where if the noise is gaussian then + + + align:start position:0% +where if the noise is gaussian then +least squares gives you the best + + align:start position:0% +least squares gives you the best + + + align:start position:0% +least squares gives you the best +possible answer it's it's not just hand + + align:start position:0% +possible answer it's it's not just hand + + + align:start position:0% +possible answer it's it's not just hand +waving but you know maximum likelihood + + align:start position:0% +waving but you know maximum likelihood + + + align:start position:0% +waving but you know maximum likelihood +all those wonderful things + + align:start position:0% + + + + align:start position:0% + +so uh + + align:start position:0% +so uh + + + align:start position:0% +so uh +how do we deal with this problem + + align:start position:0% +how do we deal with this problem + + + align:start position:0% +how do we deal with this problem +well uh the various approaches the one + + align:start position:0% +well uh the various approaches the one + + + align:start position:0% +well uh the various approaches the one +i'm going to talk about is called + + align:start position:0% +i'm going to talk about is called + + + align:start position:0% +i'm going to talk about is called +ransack random sample + + align:start position:0% + + + + align:start position:0% + +i don't know agreement + + align:start position:0% + + + + align:start position:0% + +and it's + + align:start position:0% + + + + align:start position:0% + +fishler and bowles invented it + + align:start position:0% +fishler and bowles invented it + + + align:start position:0% +fishler and bowles invented it +at sri + + align:start position:0% +at sri + + + align:start position:0% +at sri +stanford research institute which is you + + align:start position:0% +stanford research institute which is you + + + align:start position:0% +stanford research institute which is you +know connected + + align:start position:0% +know connected + + + align:start position:0% +know connected +to stanford in some way + + align:start position:0% +to stanford in some way + + + align:start position:0% +to stanford in some way +although + + align:start position:0% +although + + + align:start position:0% +although +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +because they do classified work it's not + + align:start position:0% +because they do classified work it's not + + + align:start position:0% +because they do classified work it's not +as intimately connected as they see cell + + align:start position:0% +as intimately connected as they see cell + + + align:start position:0% +as intimately connected as they see cell +it's more like lincoln labs anyway what + + align:start position:0% +it's more like lincoln labs anyway what + + + align:start position:0% +it's more like lincoln labs anyway what +they they had problems like satellite + + align:start position:0% +they they had problems like satellite + + + align:start position:0% +they they had problems like satellite +navigation + + align:start position:0% +navigation + + + align:start position:0% +navigation +and um + + align:start position:0% +and um + + + align:start position:0% +and um +making measurements of i don't know star + + align:start position:0% +making measurements of i don't know star + + + align:start position:0% +making measurements of i don't know star +positions + + align:start position:0% +positions + + + align:start position:0% +positions +gyroscopes and occasionally they'd have + + align:start position:0% +gyroscopes and occasionally they'd have + + + align:start position:0% +gyroscopes and occasionally they'd have +some + + align:start position:0% +some + + + align:start position:0% +some +massive error which would completely + + align:start position:0% +massive error which would completely + + + align:start position:0% +massive error which would completely +mess up their result + + align:start position:0% +mess up their result + + + align:start position:0% +mess up their result +even though most of the time the errors + + align:start position:0% +even though most of the time the errors + + + align:start position:0% +even though most of the time the errors +were well behaved they followed some + + align:start position:0% +were well behaved they followed some + + + align:start position:0% +were well behaved they followed some +nice + + align:start position:0% +nice + + + align:start position:0% +nice +smooth + + align:start position:0% +smooth + + + align:start position:0% +smooth +distribution with not too much spread + + align:start position:0% + + + + align:start position:0% + +so what's the idea + + align:start position:0% +so what's the idea + + + align:start position:0% +so what's the idea +step one random sample + + align:start position:0% + + + + align:start position:0% + +so if i take a random sample of these + + align:start position:0% +so if i take a random sample of these + + + align:start position:0% +so if i take a random sample of these +points + + align:start position:0% + + + + align:start position:0% + +and they're not too many outliers + + align:start position:0% +and they're not too many outliers + + + align:start position:0% +and they're not too many outliers +there's a good chance that i won't hit + + align:start position:0% +there's a good chance that i won't hit + + + align:start position:0% +there's a good chance that i won't hit +the outlier and i will get a good result + + align:start position:0% +the outlier and i will get a good result + + + align:start position:0% +the outlier and i will get a good result +and + + align:start position:0% +and + + + align:start position:0% +and +you know how how do i know that i picked + + align:start position:0% +you know how how do i know that i picked + + + align:start position:0% +you know how how do i know that i picked +the uh + + align:start position:0% +the uh + + + align:start position:0% +the uh +um + + align:start position:0% +um + + + align:start position:0% +um +random sample and how large so there are + + align:start position:0% +random sample and how large so there are + + + align:start position:0% +random sample and how large so there are +several sort of questions + + align:start position:0% +several sort of questions + + + align:start position:0% +several sort of questions +how uh how large a random sample well uh + + align:start position:0% +how uh how large a random sample well uh + + + align:start position:0% +how uh how large a random sample well uh +their recommendation was the the minimum + + align:start position:0% +their recommendation was the the minimum + + + align:start position:0% +their recommendation was the the minimum +needed to fix the transformation so in + + align:start position:0% +needed to fix the transformation so in + + + align:start position:0% +needed to fix the transformation so in +our case of absolute orientation it + + align:start position:0% +our case of absolute orientation it + + + align:start position:0% +our case of absolute orientation it +would be three + + align:start position:0% +would be three + + + align:start position:0% +would be three +now we know + + align:start position:0% +now we know + + + align:start position:0% +now we know +if we get you know a thousand + + align:start position:0% +if we get you know a thousand + + + align:start position:0% +if we get you know a thousand +correspondences we're going to get much + + align:start position:0% +correspondences we're going to get much + + + align:start position:0% +correspondences we're going to get much +better results than with three + + align:start position:0% +better results than with three + + + align:start position:0% +better results than with three +it sort of goes as one over the square + + align:start position:0% +it sort of goes as one over the square + + + align:start position:0% +it sort of goes as one over the square +root of n + + align:start position:0% +root of n + + + align:start position:0% +root of n +uh so + + align:start position:0% +uh so + + + align:start position:0% +uh so +so that's sort of limiting uh the + + align:start position:0% +so that's sort of limiting uh the + + + align:start position:0% +so that's sort of limiting uh the +accuracy so some other people recommend + + align:start position:0% +accuracy so some other people recommend + + + align:start position:0% +accuracy so some other people recommend +that you use more but + + align:start position:0% +that you use more but + + + align:start position:0% +that you use more but +and then what do you do so now you take + + align:start position:0% +and then what do you do so now you take + + + align:start position:0% +and then what do you do so now you take +the random sample and you do a best fit + + align:start position:0% +the random sample and you do a best fit + + + align:start position:0% +the random sample and you do a best fit +typically least squares because it's + + align:start position:0% +typically least squares because it's + + + align:start position:0% +typically least squares because it's +efficient and easy to understand so + + align:start position:0% +efficient and easy to understand so + + + align:start position:0% +efficient and easy to understand so +okay and then + + align:start position:0% +okay and then + + + align:start position:0% +okay and then +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +check how much of the data + + align:start position:0% + + + + align:start position:0% + +and so what you do is if that's your fit + + align:start position:0% +and so what you do is if that's your fit + + + align:start position:0% +and so what you do is if that's your fit +then you + + align:start position:0% + + + + align:start position:0% + +have some sort of band + + align:start position:0% +have some sort of band + + + align:start position:0% +have some sort of band +and + + align:start position:0% +and + + + align:start position:0% +and +you count how many of them fall inside + + align:start position:0% +you count how many of them fall inside + + + align:start position:0% +you count how many of them fall inside +and notice that this involves some kind + + align:start position:0% +and notice that this involves some kind + + + align:start position:0% +and notice that this involves some kind +of threshold + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +you know in our case here let's say that + + align:start position:0% +you know in our case here let's say that + + + align:start position:0% +you know in our case here let's say that +all but one point fall in that band then + + align:start position:0% +all but one point fall in that band then + + + align:start position:0% +all but one point fall in that band then +we say we're done + + align:start position:0% +we say we're done + + + align:start position:0% +we say we're done +uh if not uh we take another uh random + + align:start position:0% +uh if not uh we take another uh random + + + align:start position:0% +uh if not uh we take another uh random +sample and we do this operation again + + align:start position:0% +sample and we do this operation again + + + align:start position:0% +sample and we do this operation again +and and they're all sorts of interesting + + align:start position:0% +and and they're all sorts of interesting + + + align:start position:0% +and and they're all sorts of interesting +issues you know one of them is you kind + + align:start position:0% +issues you know one of them is you kind + + + align:start position:0% +issues you know one of them is you kind +of have to know + + align:start position:0% +of have to know + + + align:start position:0% +of have to know +uh what the ratio of in in liars to + + align:start position:0% +uh what the ratio of in in liars to + + + align:start position:0% +uh what the ratio of in in liars to +outliers is + + align:start position:0% + + + + align:start position:0% + +so you have to have some sort of model + + align:start position:0% +so you have to have some sort of model + + + align:start position:0% +so you have to have some sort of model +of your measurement process + + align:start position:0% +of your measurement process + + + align:start position:0% +of your measurement process +right because that's going to control + + align:start position:0% +right because that's going to control + + + align:start position:0% +right because that's going to control +how you set the threshold so you need to + + align:start position:0% +how you set the threshold so you need to + + + align:start position:0% +how you set the threshold so you need to +know something about the noise to set + + align:start position:0% +know something about the noise to set + + + align:start position:0% +know something about the noise to set +that threshold and then you need to know + + align:start position:0% +that threshold and then you need to know + + + align:start position:0% +that threshold and then you need to know +you know how many so there are two + + align:start position:0% +you know how many so there are two + + + align:start position:0% +you know how many so there are two +thresholds there's a threshold here of + + align:start position:0% +thresholds there's a threshold here of + + + align:start position:0% +thresholds there's a threshold here of +the band + + align:start position:0% +the band + + + align:start position:0% +the band +uh that determines whether these are uh + + align:start position:0% +uh that determines whether these are uh + + + align:start position:0% +uh that determines whether these are uh +you know + + align:start position:0% +you know + + + align:start position:0% +you know +in the in in liars or not and then + + align:start position:0% +in the in in liars or not and then + + + align:start position:0% +in the in in liars or not and then +there's a second threshold here + + align:start position:0% +there's a second threshold here + + + align:start position:0% +there's a second threshold here +that says um + + align:start position:0% +that says um + + + align:start position:0% +that says um +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +oops scared her with some equations + + align:start position:0% +oops scared her with some equations + + + align:start position:0% +oops scared her with some equations +um + + align:start position:0% +um + + + align:start position:0% +um +so uh + + align:start position:0% +so uh + + + align:start position:0% +so uh +if not enough so we got + + align:start position:0% +if not enough so we got + + + align:start position:0% +if not enough so we got +sort of arbitrary numbers in there which + + align:start position:0% +sort of arbitrary numbers in there which + + + align:start position:0% +sort of arbitrary numbers in there which +assume that you know something about the + + align:start position:0% +assume that you know something about the + + + align:start position:0% +assume that you know something about the +data + + align:start position:0% +data + + + align:start position:0% +data +and this works uh pretty well um + + align:start position:0% +and this works uh pretty well um + + + align:start position:0% +and this works uh pretty well um +i mean i guess you have to have some + + align:start position:0% +i mean i guess you have to have some + + + align:start position:0% +i mean i guess you have to have some +limit on not getting + + align:start position:0% +limit on not getting + + + align:start position:0% +limit on not getting +you know not doing this an infinite + + align:start position:0% +you know not doing this an infinite + + + align:start position:0% +you know not doing this an infinite +number of times so you probably have + + align:start position:0% +number of times so you probably have + + + align:start position:0% +number of times so you probably have +another exit clause which says well if + + align:start position:0% +another exit clause which says well if + + + align:start position:0% +another exit clause which says well if +you've tried 100 random samples then + + align:start position:0% +you've tried 100 random samples then + + + align:start position:0% +you've tried 100 random samples then +let's stop + + align:start position:0% +let's stop + + + align:start position:0% +let's stop +uh + + align:start position:0% +uh + + + align:start position:0% +uh +then probably your assumptions about the + + align:start position:0% +then probably your assumptions about the + + + align:start position:0% +then probably your assumptions about the +model are wrong and the thresholds + + align:start position:0% +model are wrong and the thresholds + + + align:start position:0% +model are wrong and the thresholds +aren't right so + + align:start position:0% +aren't right so + + + align:start position:0% +aren't right so +uh need to give up + + align:start position:0% +uh need to give up + + + align:start position:0% +uh need to give up +and they're variations of this so that's + + align:start position:0% +and they're variations of this so that's + + + align:start position:0% +and they're variations of this so that's +a good point i i didn't make that point + + align:start position:0% +a good point i i didn't make that point + + + align:start position:0% +a good point i i didn't make that point +yet but you know we're talking + + align:start position:0% +yet but you know we're talking + + + align:start position:0% +yet but you know we're talking +specifically about absolute orientation + + align:start position:0% +specifically about absolute orientation + + + align:start position:0% +specifically about absolute orientation +but this trick is to be applied uh if + + align:start position:0% +but this trick is to be applied uh if + + + align:start position:0% +but this trick is to be applied uh if +necessary if they outliers to any of the + + align:start position:0% +necessary if they outliers to any of the + + + align:start position:0% +necessary if they outliers to any of the +other least squares method so the least + + align:start position:0% +other least squares method so the least + + + align:start position:0% +other least squares method so the least +squares approach is very appealing + + align:start position:0% +squares approach is very appealing + + + align:start position:0% +squares approach is very appealing +because you get a closed form solution + + align:start position:0% +because you get a closed form solution + + + align:start position:0% +because you get a closed form solution +many times and you get a measure of how + + align:start position:0% +many times and you get a measure of how + + + align:start position:0% +many times and you get a measure of how +much the how large the error is you know + + align:start position:0% +much the how large the error is you know + + + align:start position:0% +much the how large the error is you know +standard deviation and all these good + + align:start position:0% +standard deviation and all these good + + + align:start position:0% +standard deviation and all these good +things but it's always subject to the + + align:start position:0% +things but it's always subject to the + + + align:start position:0% +things but it's always subject to the +problem of bad data and so this is + + align:start position:0% +problem of bad data and so this is + + + align:start position:0% +problem of bad data and so this is +definitely a method to consider + + align:start position:0% +definitely a method to consider + + + align:start position:0% +definitely a method to consider +in the presence of real data which + + align:start position:0% +in the presence of real data which + + + align:start position:0% +in the presence of real data which +sometimes has + + align:start position:0% +sometimes has + + + align:start position:0% +sometimes has +outliers + + align:start position:0% +outliers + + + align:start position:0% +outliers +yes okay + + align:start position:0% +yes okay + + + align:start position:0% +yes okay +and the different variations of this in + + align:start position:0% +and the different variations of this in + + + align:start position:0% +and the different variations of this in +fact the the name of it you know + + align:start position:0% +fact the the name of it you know + + + align:start position:0% +fact the the name of it you know +consensus + + align:start position:0% +consensus + + + align:start position:0% +consensus +uh kind of suggests a different approach + + align:start position:0% +uh kind of suggests a different approach + + + align:start position:0% +uh kind of suggests a different approach +more like a half transform so the way + + align:start position:0% +more like a half transform so the way + + + align:start position:0% +more like a half transform so the way +you know before i read the paper what i + + align:start position:0% +you know before i read the paper what i + + + align:start position:0% +you know before i read the paper what i +thought they were doing was the + + align:start position:0% +thought they were doing was the + + + align:start position:0% +thought they were doing was the +following + + align:start position:0% +following + + + align:start position:0% +following +you take random subset + + align:start position:0% +you take random subset + + + align:start position:0% +you take random subset +you do a fit + + align:start position:0% +you do a fit + + + align:start position:0% +you do a fit +and that gives you some + + align:start position:0% +and that gives you some + + + align:start position:0% +and that gives you some +answer like you know + + align:start position:0% +answer like you know + + + align:start position:0% +answer like you know +slope and intercept of a straight line + + align:start position:0% +slope and intercept of a straight line + + + align:start position:0% +slope and intercept of a straight line +say in this case and + + align:start position:0% +say in this case and + + + align:start position:0% +say in this case and +and you do it again do it a certain + + align:start position:0% +and you do it again do it a certain + + + align:start position:0% +and you do it again do it a certain +number of times and then you plot them + + align:start position:0% +number of times and then you plot them + + + align:start position:0% +number of times and then you plot them +in some parameter space + + align:start position:0% + + + + align:start position:0% + +and some of them will cluster tightly + + align:start position:0% +and some of them will cluster tightly + + + align:start position:0% +and some of them will cluster tightly +and some of them that included the + + align:start position:0% +and some of them that included the + + + align:start position:0% +and some of them that included the +outlier will be way off and so uh you + + align:start position:0% +outlier will be way off and so uh you + + + align:start position:0% +outlier will be way off and so uh you +know you can imagine a half transform + + align:start position:0% +know you can imagine a half transform + + + align:start position:0% +know you can imagine a half transform +method where you have an accumulator + + align:start position:0% +method where you have an accumulator + + + align:start position:0% +method where you have an accumulator +array + + align:start position:0% +array + + + align:start position:0% +array +in this parameter space + + align:start position:0% +in this parameter space + + + align:start position:0% +in this parameter space +and whenever you get an answer you + + align:start position:0% +and whenever you get an answer you + + + align:start position:0% +and whenever you get an answer you +increment that cell in the parameter + + align:start position:0% +increment that cell in the parameter + + + align:start position:0% +increment that cell in the parameter +space then after you've done it often + + align:start position:0% +space then after you've done it often + + + align:start position:0% +space then after you've done it often +enough you look for the cell that has + + align:start position:0% +enough you look for the cell that has + + + align:start position:0% +enough you look for the cell that has +the most hits + + align:start position:0% +the most hits + + + align:start position:0% +the most hits +and and that's you know kind of + + align:start position:0% + + + + align:start position:0% + +somehow + + align:start position:0% +somehow + + + align:start position:0% +somehow +hybridizing uh + + align:start position:0% +hybridizing uh + + + align:start position:0% +hybridizing uh +fishler and boll's ransack method + + align:start position:0% +fishler and boll's ransack method + + + align:start position:0% +fishler and boll's ransack method +with a half transform method and this + + align:start position:0% +with a half transform method and this + + + align:start position:0% +with a half transform method and this +also + + align:start position:0% +also + + + align:start position:0% +also +you know all of these are kind of ad hoc + + align:start position:0% +you know all of these are kind of ad hoc + + + align:start position:0% +you know all of these are kind of ad hoc +but they're very useful in practice so + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +well + + align:start position:0% +well + + + align:start position:0% +well +one of the things we're going to do + + align:start position:0% +one of the things we're going to do + + + align:start position:0% +one of the things we're going to do +a little later is to find + + align:start position:0% +a little later is to find + + + align:start position:0% +a little later is to find +representations for + + align:start position:0% +representations for + + + align:start position:0% +representations for +objects + + align:start position:0% +objects + + + align:start position:0% +objects +that particularly objects that are + + align:start position:0% +that particularly objects that are + + + align:start position:0% +that particularly objects that are +not simple polyhedra but more + + align:start position:0% +not simple polyhedra but more + + + align:start position:0% +not simple polyhedra but more +complicated + + align:start position:0% +complicated + + + align:start position:0% +complicated +and particularly objects that um + + align:start position:0% +and particularly objects that um + + + align:start position:0% +and particularly objects that um +are near convex that might not have a + + align:start position:0% +are near convex that might not have a + + + align:start position:0% +are near convex that might not have a +lot of holes and that representation + + align:start position:0% +lot of holes and that representation + + + align:start position:0% +lot of holes and that representation +is very useful for detecting things and + + align:start position:0% +is very useful for detecting things and + + + align:start position:0% +is very useful for detecting things and +finding their orientation + + align:start position:0% +finding their orientation + + + align:start position:0% +finding their orientation +and we run into + + align:start position:0% +and we run into + + + align:start position:0% +and we run into +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +the same + + align:start position:0% + + + + align:start position:0% + +orientation problems as we have over + + align:start position:0% +orientation problems as we have over + + + align:start position:0% +orientation problems as we have over +here + + align:start position:0% +here + + + align:start position:0% +here +and + + align:start position:0% + + + + align:start position:0% + +often there's not a closed form solution + + align:start position:0% +often there's not a closed form solution + + + align:start position:0% +often there's not a closed form solution +so one approach is to sort of sample the + + align:start position:0% +so one approach is to sort of sample the + + + align:start position:0% +so one approach is to sort of sample the +space of rotations + + align:start position:0% +space of rotations + + + align:start position:0% +space of rotations +and um + + align:start position:0% +and um + + + align:start position:0% +and um +how do you do this so since we're + + align:start position:0% +how do you do this so since we're + + + align:start position:0% +how do you do this so since we're +talking about + + align:start position:0% + + + + align:start position:0% + +so let me + + align:start position:0% +so let me + + + align:start position:0% +so let me +first look at sampling a sphere + + align:start position:0% +first look at sampling a sphere + + + align:start position:0% +first look at sampling a sphere +in 3d + + align:start position:0% + + + + align:start position:0% + +so + + align:start position:0% +so + + + align:start position:0% +so +one way we can do it is to use + + align:start position:0% + + + + align:start position:0% + +some sort of discretization of latitude + + align:start position:0% +some sort of discretization of latitude + + + align:start position:0% +some sort of discretization of latitude +and longitude + + align:start position:0% + + + + align:start position:0% + +you know i just + + align:start position:0% +you know i just + + + align:start position:0% +you know i just +find there's some + + align:start position:0% +find there's some + + + align:start position:0% +find there's some +people who forget what the terminology + + align:start position:0% +people who forget what the terminology + + + align:start position:0% +people who forget what the terminology +is but where these lines cross that's + + align:start position:0% +is but where these lines cross that's + + + align:start position:0% +is but where these lines cross that's +like + + align:start position:0% +like + + + align:start position:0% +like +point of convergence and if you go there + + align:start position:0% +point of convergence and if you go there + + + align:start position:0% +point of convergence and if you go there +something magical happens to you + + align:start position:0% +something magical happens to you + + + align:start position:0% +something magical happens to you +particularly if you take along crystals + + align:start position:0% +particularly if you take along crystals + + + align:start position:0% +particularly if you take along crystals +and um sometimes these are in hard to + + align:start position:0% +and um sometimes these are in hard to + + + align:start position:0% +and um sometimes these are in hard to +access places like in the middle of a + + align:start position:0% +access places like in the middle of a + + + align:start position:0% +access places like in the middle of a +military reservation + + align:start position:0% +military reservation + + + align:start position:0% +military reservation +anyway + + align:start position:0% +anyway + + + align:start position:0% +anyway +we sample them and what's wrong with + + align:start position:0% +we sample them and what's wrong with + + + align:start position:0% +we sample them and what's wrong with +that + + align:start position:0% +that + + + align:start position:0% +that +it gives us a way of sampling the whole + + align:start position:0% +it gives us a way of sampling the whole + + + align:start position:0% +it gives us a way of sampling the whole +space but obviously + + align:start position:0% +space but obviously + + + align:start position:0% +space but obviously +it's not a uniform sampling + + align:start position:0% +it's not a uniform sampling + + + align:start position:0% +it's not a uniform sampling +up here near the poles we're sampling + + align:start position:0% +up here near the poles we're sampling + + + align:start position:0% +up here near the poles we're sampling +points that are very close together + + align:start position:0% +points that are very close together + + + align:start position:0% +points that are very close together +and so that means it's inefficient that + + align:start position:0% +and so that means it's inefficient that + + + align:start position:0% +and so that means it's inefficient that +if we had + + align:start position:0% +if we had + + + align:start position:0% +if we had +used + + align:start position:0% +used + + + align:start position:0% +used +some of those points + + align:start position:0% +some of those points + + + align:start position:0% +some of those points +near the equator we could have done a + + align:start position:0% +near the equator we could have done a + + + align:start position:0% +near the equator we could have done a +better job more even job of + + align:start position:0% +better job more even job of + + + align:start position:0% +better job more even job of +sampling + + align:start position:0% +sampling + + + align:start position:0% +sampling +so you know lots of interesting + + align:start position:0% +so you know lots of interesting + + + align:start position:0% +so you know lots of interesting +questions come out of this one of them + + align:start position:0% +questions come out of this one of them + + + align:start position:0% +questions come out of this one of them +is well can we think of a better + + align:start position:0% +is well can we think of a better + + + align:start position:0% +is well can we think of a better +coordinate system so that if you sample + + align:start position:0% +coordinate system so that if you sample + + + align:start position:0% +coordinate system so that if you sample +uniformly in those two coordinates you + + align:start position:0% +uniformly in those two coordinates you + + + align:start position:0% +uniformly in those two coordinates you +will get + + align:start position:0% +will get + + + align:start position:0% +will get +a nice spacing on the sphere well + + align:start position:0% +a nice spacing on the sphere well + + + align:start position:0% +a nice spacing on the sphere well +good luck with that + + align:start position:0% +good luck with that + + + align:start position:0% +good luck with that +you can show that it's not possible + + align:start position:0% +you can show that it's not possible + + + align:start position:0% +you can show that it's not possible +so um what else can we do well um + + align:start position:0% +so um what else can we do well um + + + align:start position:0% +so um what else can we do well um +we could generate random theta and phi + + align:start position:0% +we could generate random theta and phi + + + align:start position:0% +we could generate random theta and phi +using some distribution so that + + align:start position:0% +using some distribution so that + + + align:start position:0% +using some distribution so that +let's see latitude goes from minus pi + + align:start position:0% +let's see latitude goes from minus pi + + + align:start position:0% +let's see latitude goes from minus pi +over 2 to + + align:start position:0% + + + + align:start position:0% + +pi over 2 + + align:start position:0% +pi over 2 + + + align:start position:0% +pi over 2 +and longitude minus pi + + align:start position:0% +and longitude minus pi + + + align:start position:0% +and longitude minus pi +to + + align:start position:0% + + + + align:start position:0% + +so we could you know divide this up we + + align:start position:0% +so we could you know divide this up we + + + align:start position:0% +so we could you know divide this up we +could have a random number generator + + align:start position:0% +could have a random number generator + + + align:start position:0% +could have a random number generator +that goes between minus pi and plus pi + + align:start position:0% +that goes between minus pi and plus pi + + + align:start position:0% +that goes between minus pi and plus pi +and one that goes between minus pi over + + align:start position:0% +and one that goes between minus pi over + + + align:start position:0% +and one that goes between minus pi over +two and plus pi over two uniform + + align:start position:0% +two and plus pi over two uniform + + + align:start position:0% +two and plus pi over two uniform +and of course we'd have exactly the same + + align:start position:0% +and of course we'd have exactly the same + + + align:start position:0% +and of course we'd have exactly the same +problem right because we're going to + + align:start position:0% +problem right because we're going to + + + align:start position:0% +problem right because we're going to +sample the polar region more strongly + + align:start position:0% +sample the polar region more strongly + + + align:start position:0% +sample the polar region more strongly +than than the other region so that's + + align:start position:0% +than than the other region so that's + + + align:start position:0% +than than the other region so that's +that's not very good so how to solve + + align:start position:0% +that's not very good so how to solve + + + align:start position:0% +that's not very good so how to solve +that well the trouble is we got this + + align:start position:0% +that well the trouble is we got this + + + align:start position:0% +that well the trouble is we got this +curved surface if we had like a + + align:start position:0% +curved surface if we had like a + + + align:start position:0% +curved surface if we had like a +cartesian world + + align:start position:0% +cartesian world + + + align:start position:0% +cartesian world +would be easy to sample you know if i + + align:start position:0% +would be easy to sample you know if i + + + align:start position:0% +would be easy to sample you know if i +have a cube + + align:start position:0% + + + + align:start position:0% + +i can just + + align:start position:0% +i can just + + + align:start position:0% +i can just +have a uniform distribution in x a + + align:start position:0% +have a uniform distribution in x a + + + align:start position:0% +have a uniform distribution in x a +uniform distribution y uniform + + align:start position:0% +uniform distribution y uniform + + + align:start position:0% +uniform distribution y uniform +distribution in z and i call the random + + align:start position:0% +distribution in z and i call the random + + + align:start position:0% +distribution in z and i call the random +number generator three times i have a + + align:start position:0% +number generator three times i have a + + + align:start position:0% +number generator three times i have a +point in that space and it's uh + + align:start position:0% +point in that space and it's uh + + + align:start position:0% +point in that space and it's uh +if i do this a lot i don't expect there + + align:start position:0% +if i do this a lot i don't expect there + + + align:start position:0% +if i do this a lot i don't expect there +to be + + align:start position:0% +to be + + + align:start position:0% +to be +sort of aggregation systematic + + align:start position:0% +sort of aggregation systematic + + + align:start position:0% +sort of aggregation systematic +uh clumping you know as we as we have in + + align:start position:0% +uh clumping you know as we as we have in + + + align:start position:0% +uh clumping you know as we as we have in +the case of of the sphere + + align:start position:0% +the case of of the sphere + + + align:start position:0% +the case of of the sphere +so how to go from this to that well one + + align:start position:0% +so how to go from this to that well one + + + align:start position:0% +so how to go from this to that well one +thing to do is to + + align:start position:0% + + + + align:start position:0% + +inscribe a sphere in the cube + + align:start position:0% +inscribe a sphere in the cube + + + align:start position:0% +inscribe a sphere in the cube +and then somehow map + + align:start position:0% +and then somehow map + + + align:start position:0% +and then somehow map +the cube + + align:start position:0% +the cube + + + align:start position:0% +the cube +onto the sphere + + align:start position:0% + + + + align:start position:0% + +so one way to do that would be to + + align:start position:0% +so one way to do that would be to + + + align:start position:0% +so one way to do that would be to +imagine the origins at the very center + + align:start position:0% +imagine the origins at the very center + + + align:start position:0% +imagine the origins at the very center +of this thing and any point on the + + align:start position:0% +of this thing and any point on the + + + align:start position:0% +of this thing and any point on the +sphere we draw a line and then we find + + align:start position:0% +sphere we draw a line and then we find + + + align:start position:0% +sphere we draw a line and then we find +where it intersects the uh + + align:start position:0% +where it intersects the uh + + + align:start position:0% +where it intersects the uh +the sphere + + align:start position:0% +the sphere + + + align:start position:0% +the sphere +any point in the cube + + align:start position:0% +any point in the cube + + + align:start position:0% +any point in the cube +we sample and and that point could be + + align:start position:0% +we sample and and that point could be + + + align:start position:0% +we sample and and that point could be +inside this sphere so if it's inside the + + align:start position:0% +inside this sphere so if it's inside the + + + align:start position:0% +inside this sphere so if it's inside the +sphere we draw that line + + align:start position:0% +sphere we draw that line + + + align:start position:0% +sphere we draw that line +and we project it out to the sphere + + align:start position:0% +and we project it out to the sphere + + + align:start position:0% +and we project it out to the sphere +in this case we + + align:start position:0% +in this case we + + + align:start position:0% +in this case we +so + + align:start position:0% +so + + + align:start position:0% +so +to be clear again we just have uniform + + align:start position:0% +to be clear again we just have uniform + + + align:start position:0% +to be clear again we just have uniform +you know like most languages give you + + align:start position:0% +you know like most languages give you + + + align:start position:0% +you know like most languages give you +the ability to generate + + align:start position:0% +the ability to generate + + + align:start position:0% +the ability to generate +uniform random numbers between zero and + + align:start position:0% +uniform random numbers between zero and + + + align:start position:0% +uniform random numbers between zero and +one you just map them on to that + + align:start position:0% +one you just map them on to that + + + align:start position:0% +one you just map them on to that +interval in x and then another one + + align:start position:0% +interval in x and then another one + + + align:start position:0% +interval in x and then another one +interval and y another one interval and + + align:start position:0% +interval and y another one interval and + + + align:start position:0% +interval and y another one interval and +z there's a point in 3d + + align:start position:0% +z there's a point in 3d + + + align:start position:0% +z there's a point in 3d +and you have to reduce it to the surface + + align:start position:0% +and you have to reduce it to the surface + + + align:start position:0% +and you have to reduce it to the surface +of a sphere well you just normalize it + + align:start position:0% +of a sphere well you just normalize it + + + align:start position:0% +of a sphere well you just normalize it +so you have a three vector you just take + + align:start position:0% +so you have a three vector you just take + + + align:start position:0% +so you have a three vector you just take +the unit vector version of that and + + align:start position:0% +the unit vector version of that and + + + align:start position:0% +the unit vector version of that and +you're done + + align:start position:0% +you're done + + + align:start position:0% +you're done +so does that give me a uniform + + align:start position:0% +so does that give me a uniform + + + align:start position:0% +so does that give me a uniform +distribution on the surface of the + + align:start position:0% +distribution on the surface of the + + + align:start position:0% +distribution on the surface of the +sphere + + align:start position:0% +sphere + + + align:start position:0% +sphere +no okay so we have some head shaking and + + align:start position:0% +no okay so we have some head shaking and + + + align:start position:0% +no okay so we have some head shaking and +that's because well this the uh cube + + align:start position:0% +that's because well this the uh cube + + + align:start position:0% +that's because well this the uh cube +is uh has these corners + + align:start position:0% +is uh has these corners + + + align:start position:0% +is uh has these corners +and so + + align:start position:0% +and so + + + align:start position:0% +and so +there will be a higher density of points + + align:start position:0% +there will be a higher density of points + + + align:start position:0% +there will be a higher density of points +in the directions of the corners than + + align:start position:0% +in the directions of the corners than + + + align:start position:0% +in the directions of the corners than +there will be + + align:start position:0% +there will be + + + align:start position:0% +there will be +where your + + align:start position:0% +where your + + + align:start position:0% +where your +tangent + + align:start position:0% +tangent + + + align:start position:0% +tangent +where the sphere is tangent to the cube + + align:start position:0% +where the sphere is tangent to the cube + + + align:start position:0% +where the sphere is tangent to the cube +it's better though this one's only off + + align:start position:0% +it's better though this one's only off + + + align:start position:0% +it's better though this one's only off +by um + + align:start position:0% +by um + + + align:start position:0% +by um +i forget factor of 4 over pi + + align:start position:0% +i forget factor of 4 over pi + + + align:start position:0% +i forget factor of 4 over pi +4 over pi i think or + + align:start position:0% +4 over pi i think or + + + align:start position:0% +4 over pi i think or +or pi over 3 no 4 over pi + + align:start position:0% +or pi over 3 no 4 over pi + + + align:start position:0% +or pi over 3 no 4 over pi +so so this isn't too bad + + align:start position:0% +so so this isn't too bad + + + align:start position:0% +so so this isn't too bad +so how can you do better how can you + + align:start position:0% +so how can you do better how can you + + + align:start position:0% +so how can you do better how can you +take this idea and fix it so that you + + align:start position:0% +take this idea and fix it so that you + + + align:start position:0% +take this idea and fix it so that you +don't have the corner problem + + align:start position:0% + + + + align:start position:0% + +tessellated shapes yeah we could teslate + + align:start position:0% +tessellated shapes yeah we could teslate + + + align:start position:0% +tessellated shapes yeah we could teslate +the surface of the sphere using regular + + align:start position:0% +the surface of the sphere using regular + + + align:start position:0% +the surface of the sphere using regular +solids + + align:start position:0% +solids + + + align:start position:0% +solids +the magic things that plato organized + + align:start position:0% +the magic things that plato organized + + + align:start position:0% +the magic things that plato organized +his society about + + align:start position:0% +his society about + + + align:start position:0% +his society about +that's certainly a good good approach + + align:start position:0% +that's certainly a good good approach + + + align:start position:0% +that's certainly a good good approach +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +is there some way of discarding some of + + align:start position:0% +is there some way of discarding some of + + + align:start position:0% +is there some way of discarding some of +these points that we + + align:start position:0% +these points that we + + + align:start position:0% +these points that we +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +we're generating here + + align:start position:0% +we're generating here + + + align:start position:0% +we're generating here +okay so contracting this aggregation + + align:start position:0% +okay so contracting this aggregation + + + align:start position:0% +okay so contracting this aggregation +near the corners uh we could introduce + + align:start position:0% +near the corners uh we could introduce + + + align:start position:0% +near the corners uh we could introduce +some sort of weight and for example if + + align:start position:0% +some sort of weight and for example if + + + align:start position:0% +some sort of weight and for example if +we could uh give the points when + + align:start position:0% +we could uh give the points when + + + align:start position:0% +we could uh give the points when +projected a weight we could just make it + + align:start position:0% +projected a weight we could just make it + + + align:start position:0% +projected a weight we could just make it +proportional to + + align:start position:0% +proportional to + + + align:start position:0% +proportional to +inversely proportional to the radius + + align:start position:0% +inversely proportional to the radius + + + align:start position:0% +inversely proportional to the radius +so if we're far out then + + align:start position:0% +so if we're far out then + + + align:start position:0% +so if we're far out then +so uh that that's an uh good idea um + + align:start position:0% +so uh that that's an uh good idea um + + + align:start position:0% +so uh that that's an uh good idea um +another idea is to say well + + align:start position:0% +another idea is to say well + + + align:start position:0% +another idea is to say well +uh + + align:start position:0% +uh + + + align:start position:0% +uh +we could just throw away all the points + + align:start position:0% +we could just throw away all the points + + + align:start position:0% +we could just throw away all the points +that are outside the sphere + + align:start position:0% +that are outside the sphere + + + align:start position:0% +that are outside the sphere +and then we have a random distribution + + align:start position:0% +and then we have a random distribution + + + align:start position:0% +and then we have a random distribution +of points in a sphere + + align:start position:0% +of points in a sphere + + + align:start position:0% +of points in a sphere +right so we we again we generate points + + align:start position:0% +right so we we again we generate points + + + align:start position:0% +right so we we again we generate points +in the cube but then we check whether + + align:start position:0% +in the cube but then we check whether + + + align:start position:0% +in the cube but then we check whether +their radius is bigger than one and if + + align:start position:0% +their radius is bigger than one and if + + + align:start position:0% +their radius is bigger than one and if +it's bigger than one we chuck it out and + + align:start position:0% +it's bigger than one we chuck it out and + + + align:start position:0% +it's bigger than one we chuck it out and +it has a disadvantage that you're not + + align:start position:0% +it has a disadvantage that you're not + + + align:start position:0% +it has a disadvantage that you're not +generating points at a fixed rate that + + align:start position:0% +generating points at a fixed rate that + + + align:start position:0% +generating points at a fixed rate that +it costs you more sometimes because you + + align:start position:0% +it costs you more sometimes because you + + + align:start position:0% +it costs you more sometimes because you +have to go back and regenerate it and + + align:start position:0% +have to go back and regenerate it and + + + align:start position:0% +have to go back and regenerate it and +maybe regenerate it again + + align:start position:0% +maybe regenerate it again + + + align:start position:0% +maybe regenerate it again +so there's a + + align:start position:0% +so there's a + + + align:start position:0% +so there's a +disadvantage but uh what happens then + + align:start position:0% +disadvantage but uh what happens then + + + align:start position:0% +disadvantage but uh what happens then +well then we have + + align:start position:0% +well then we have + + + align:start position:0% +well then we have +a uniform sampling of the inside of the + + align:start position:0% +a uniform sampling of the inside of the + + + align:start position:0% +a uniform sampling of the inside of the +sphere + + align:start position:0% +sphere + + + align:start position:0% +sphere +uh and that's + + align:start position:0% +uh and that's + + + align:start position:0% +uh and that's +almost good enough now we just need to + + align:start position:0% +almost good enough now we just need to + + + align:start position:0% +almost good enough now we just need to +project all those points onto the + + align:start position:0% +project all those points onto the + + + align:start position:0% +project all those points onto the +surface of the sphere and if we want to + + align:start position:0% +surface of the sphere and if we want to + + + align:start position:0% +surface of the sphere and if we want to +avoid nasty numerical problems we might + + align:start position:0% +avoid nasty numerical problems we might + + + align:start position:0% +avoid nasty numerical problems we might +want to also throw away + + align:start position:0% +want to also throw away + + + align:start position:0% +want to also throw away +all points that are close to the origin + + align:start position:0% +all points that are close to the origin + + + align:start position:0% +all points that are close to the origin +right because then we might have numbers + + align:start position:0% +right because then we might have numbers + + + align:start position:0% +right because then we might have numbers +you're dividing by by normalizing the + + align:start position:0% +you're dividing by by normalizing the + + + align:start position:0% +you're dividing by by normalizing the +vector to make it a unit vector you + + align:start position:0% +vector to make it a unit vector you + + + align:start position:0% +vector to make it a unit vector you +might be dividing by some small number + + align:start position:0% +might be dividing by some small number + + + align:start position:0% +might be dividing by some small number +which is going to introduce some error + + align:start position:0% +which is going to introduce some error + + + align:start position:0% +which is going to introduce some error +and biases so you you generate + + align:start position:0% +and biases so you you generate + + + align:start position:0% +and biases so you you generate +points uniform in a cube + + align:start position:0% +points uniform in a cube + + + align:start position:0% +points uniform in a cube +you throw away all points above some + + align:start position:0% +you throw away all points above some + + + align:start position:0% +you throw away all points above some +certain radius and you throw away all + + align:start position:0% +certain radius and you throw away all + + + align:start position:0% +certain radius and you throw away all +points that are below a small radius + + align:start position:0% +points that are below a small radius + + + align:start position:0% +points that are below a small radius +i've drawn it a little big there + + align:start position:0% +i've drawn it a little big there + + + align:start position:0% +i've drawn it a little big there +and then normalize them and so there's + + align:start position:0% +and then normalize them and so there's + + + align:start position:0% +and then normalize them and so there's +your + + align:start position:0% +your + + + align:start position:0% +your +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +there's your point uh + + align:start position:0% +there's your point uh + + + align:start position:0% +there's your point uh +sampling of the surface of the sphere + + align:start position:0% +sampling of the surface of the sphere + + + align:start position:0% +sampling of the surface of the sphere +so + + align:start position:0% +so + + + align:start position:0% +so +we may not care about the sphere + + align:start position:0% +we may not care about the sphere + + + align:start position:0% +we may not care about the sphere +but i can't draw this in 4d + + align:start position:0% +but i can't draw this in 4d + + + align:start position:0% +but i can't draw this in 4d +but it works exactly the same way right + + align:start position:0% +but it works exactly the same way right + + + align:start position:0% +but it works exactly the same way right +if we want to have a nice uniform + + align:start position:0% +if we want to have a nice uniform + + + align:start position:0% +if we want to have a nice uniform +sampling of 4d space one way + + align:start position:0% +sampling of 4d space one way + + + align:start position:0% +sampling of 4d space one way +a random sampling one way of doing it is + + align:start position:0% +a random sampling one way of doing it is + + + align:start position:0% +a random sampling one way of doing it is +exactly this we do a four dimensional + + align:start position:0% +exactly this we do a four dimensional + + + align:start position:0% +exactly this we do a four dimensional +equivalent of the cube + + align:start position:0% +equivalent of the cube + + + align:start position:0% +equivalent of the cube +so we generate four random numbers + + align:start position:0% +so we generate four random numbers + + + align:start position:0% +so we generate four random numbers +for x y z and say w + + align:start position:0% +for x y z and say w + + + align:start position:0% +for x y z and say w +and then we check whether there are + + align:start position:0% +and then we check whether there are + + + align:start position:0% +and then we check whether there are +sum of squares is larger than one if so + + align:start position:0% +sum of squares is larger than one if so + + + align:start position:0% +sum of squares is larger than one if so +try again + + align:start position:0% +try again + + + align:start position:0% +try again +if not + + align:start position:0% +if not + + + align:start position:0% +if not +then we + + align:start position:0% +then we + + + align:start position:0% +then we +turn them into a unit quaternion + + align:start position:0% +turn them into a unit quaternion + + + align:start position:0% +turn them into a unit quaternion +and that gives us a very simple way of + + align:start position:0% +and that gives us a very simple way of + + + align:start position:0% +and that gives us a very simple way of +getting a uniform + + align:start position:0% +getting a uniform + + + align:start position:0% +getting a uniform +sampling of that space + + align:start position:0% + + + + align:start position:0% + +now + + align:start position:0% +now + + + align:start position:0% +now +there was mention of uh + + align:start position:0% +there was mention of uh + + + align:start position:0% +there was mention of uh +regular polyhedra so that's an important + + align:start position:0% +regular polyhedra so that's an important + + + align:start position:0% +regular polyhedra so that's an important +thing to think about so we could + + align:start position:0% +thing to think about so we could + + + align:start position:0% +thing to think about so we could +so what what are they well they're + + align:start position:0% +so what what are they well they're + + + align:start position:0% +so what what are they well they're +tetrahedra the + + align:start position:0% +tetrahedra the + + + align:start position:0% +tetrahedra the +hexahedra + + align:start position:0% +hexahedra + + + align:start position:0% +hexahedra +octahedra + + align:start position:0% + + + + align:start position:0% + +dodecahedra + + align:start position:0% + + + + align:start position:0% + +and ikosa + + align:start position:0% + + + + align:start position:0% + +so these are the so-called regular + + align:start position:0% +so these are the so-called regular + + + align:start position:0% +so these are the so-called regular +solids + + align:start position:0% +solids + + + align:start position:0% +solids +regular polyhedra + + align:start position:0% + + + + align:start position:0% + +that means that + + align:start position:0% +that means that + + + align:start position:0% +that means that +all of their faces are the + + align:start position:0% +all of their faces are the + + + align:start position:0% +all of their faces are the +same and those aren't the only objects + + align:start position:0% +same and those aren't the only objects + + + align:start position:0% +same and those aren't the only objects +of interest but uh let's start with + + align:start position:0% +of interest but uh let's start with + + + align:start position:0% +of interest but uh let's start with +those + + align:start position:0% +those + + + align:start position:0% +those +so + + align:start position:0% +so + + + align:start position:0% +so +if we uh want to + + align:start position:0% +if we uh want to + + + align:start position:0% +if we uh want to +sample the surface of the sphere + + align:start position:0% +sample the surface of the sphere + + + align:start position:0% +sample the surface of the sphere +one other way is to project out well + + align:start position:0% +one other way is to project out well + + + align:start position:0% +one other way is to project out well +these are obviously on spheres but you + + align:start position:0% +these are obviously on spheres but you + + + align:start position:0% +these are obviously on spheres but you +can imagine them placed at the origin + + align:start position:0% +can imagine them placed at the origin + + + align:start position:0% +can imagine them placed at the origin +and then projected out onto the sphere + + align:start position:0% +and then projected out onto the sphere + + + align:start position:0% +and then projected out onto the sphere +and we get + + align:start position:0% +and we get + + + align:start position:0% +and we get +great circles wherever there's an edge + + align:start position:0% +great circles wherever there's an edge + + + align:start position:0% +great circles wherever there's an edge +on one of these objects + + align:start position:0% +on one of these objects + + + align:start position:0% +on one of these objects +and so that's a way of dividing up the + + align:start position:0% +and so that's a way of dividing up the + + + align:start position:0% +and so that's a way of dividing up the +sphere in a perfectly regular way + + align:start position:0% + + + + align:start position:0% + +what's what's the problem well + + align:start position:0% +what's what's the problem well + + + align:start position:0% +what's what's the problem well +the only thing is that there aren't too + + align:start position:0% +the only thing is that there aren't too + + + align:start position:0% +the only thing is that there aren't too +many facets so tetrahedra 4 6 8 + + align:start position:0% +many facets so tetrahedra 4 6 8 + + + align:start position:0% +many facets so tetrahedra 4 6 8 +12 20. + + align:start position:0% +12 20. + + + align:start position:0% +12 20. +so we're not dividing the sphere up very + + align:start position:0% +so we're not dividing the sphere up very + + + align:start position:0% +so we're not dividing the sphere up very +finely and as plato discovered that's it + + align:start position:0% +finely and as plato discovered that's it + + + align:start position:0% +finely and as plato discovered that's it +there aren't any more + + align:start position:0% +there aren't any more + + + align:start position:0% +there aren't any more +so that means we have to subdivide and + + align:start position:0% +so that means we have to subdivide and + + + align:start position:0% +so that means we have to subdivide and +and + + align:start position:0% +and + + + align:start position:0% +and +you might say well wait what happened to + + align:start position:0% +you might say well wait what happened to + + + align:start position:0% +you might say well wait what happened to +the soccer ball how many faces on the + + align:start position:0% +the soccer ball how many faces on the + + + align:start position:0% +the soccer ball how many faces on the +soccer ball + + align:start position:0% + + + + align:start position:0% + +how can people play games and not even + + align:start position:0% +how can people play games and not even + + + align:start position:0% +how can people play games and not even +know how many anyway 32 + + align:start position:0% +know how many anyway 32 + + + align:start position:0% +know how many anyway 32 +so it's a mix of the dodecahedron and + + align:start position:0% +so it's a mix of the dodecahedron and + + + align:start position:0% +so it's a mix of the dodecahedron and +the icosahedron and it uh and it's not + + align:start position:0% +the icosahedron and it uh and it's not + + + align:start position:0% +the icosahedron and it uh and it's not +in this group because it's semi-regular + + align:start position:0% + + + + align:start position:0% + +so uh i guess these are + + align:start position:0% +so uh i guess these are + + + align:start position:0% +so uh i guess these are +plato gets created for these + + align:start position:0% +plato gets created for these + + + align:start position:0% +plato gets created for these +and archimedes gets created for the + + align:start position:0% +and archimedes gets created for the + + + align:start position:0% +and archimedes gets created for the +semi-regular one + + align:start position:0% + + + + align:start position:0% + +and there's a there's a whole bunch uh + + align:start position:0% +and there's a there's a whole bunch uh + + + align:start position:0% +and there's a there's a whole bunch uh +i don't know + + align:start position:0% +i don't know + + + align:start position:0% +i don't know +14 or it depends on how you count + + align:start position:0% +14 or it depends on how you count + + + align:start position:0% +14 or it depends on how you count +so uh these objects are all their own + + align:start position:0% +so uh these objects are all their own + + + align:start position:0% +so uh these objects are all their own +mirror images + + align:start position:0% +mirror images + + + align:start position:0% +mirror images +but when you get to the semi-regular + + align:start position:0% +but when you get to the semi-regular + + + align:start position:0% +but when you get to the semi-regular +objects + + align:start position:0% +objects + + + align:start position:0% +objects +there's one + + align:start position:0% +there's one + + + align:start position:0% +there's one +where the mirror image is actually + + align:start position:0% +where the mirror image is actually + + + align:start position:0% +where the mirror image is actually +different in other words you can't + + align:start position:0% +different in other words you can't + + + align:start position:0% +different in other words you can't +rotate it to bring it into alignment + + align:start position:0% +rotate it to bring it into alignment + + + align:start position:0% +rotate it to bring it into alignment +with itself + + align:start position:0% +with itself + + + align:start position:0% +with itself +and so + + align:start position:0% +and so + + + align:start position:0% +and so +if you count that it's 14 if you don't + + align:start position:0% +if you count that it's 14 if you don't + + + align:start position:0% +if you count that it's 14 if you don't +count that it's 13. and the soccer ball + + align:start position:0% +count that it's 13. and the soccer ball + + + align:start position:0% +count that it's 13. and the soccer ball +somewhere in here the + + align:start position:0% +somewhere in here the + + + align:start position:0% +somewhere in here the +the icosa dodecahedron + + align:start position:0% + + + + align:start position:0% + +so what's the difference well the + + align:start position:0% +so what's the difference well the + + + align:start position:0% +so what's the difference well the +semi-regular ones still have facets that + + align:start position:0% +semi-regular ones still have facets that + + + align:start position:0% +semi-regular ones still have facets that +are regular polygons + + align:start position:0% +are regular polygons + + + align:start position:0% +are regular polygons +so you know triangle squares + + align:start position:0% +so you know triangle squares + + + align:start position:0% +so you know triangle squares +dodecahedrons + + align:start position:0% +dodecahedrons + + + align:start position:0% +dodecahedrons +hexagons et cetera + + align:start position:0% +hexagons et cetera + + + align:start position:0% +hexagons et cetera +but + + align:start position:0% +but + + + align:start position:0% +but +you're now allowed + + align:start position:0% +you're now allowed + + + align:start position:0% +you're now allowed +to have more than one type so over here + + align:start position:0% +to have more than one type so over here + + + align:start position:0% +to have more than one type so over here +once you decided on you know triangles + + align:start position:0% +once you decided on you know triangles + + + align:start position:0% +once you decided on you know triangles +for the facets they all have to be + + align:start position:0% +for the facets they all have to be + + + align:start position:0% +for the facets they all have to be +triangles over here you can have a mix + + align:start position:0% +triangles over here you can have a mix + + + align:start position:0% +triangles over here you can have a mix +so the + + align:start position:0% +so the + + + align:start position:0% +so the +the soccer ball is a mix of + + align:start position:0% +the soccer ball is a mix of + + + align:start position:0% +the soccer ball is a mix of +hexagons and dotec + + align:start position:0% +hexagons and dotec + + + align:start position:0% +hexagons and dotec +and five-sided figures + + align:start position:0% +and five-sided figures + + + align:start position:0% +and five-sided figures +so that gives you a + + align:start position:0% +so that gives you a + + + align:start position:0% +so that gives you a +larger variety but + + align:start position:0% +larger variety but + + + align:start position:0% +larger variety but +you know think about the fact that they + + align:start position:0% +you know think about the fact that they + + + align:start position:0% +you know think about the fact that they +all have to have the same edge length + + align:start position:0% +all have to have the same edge length + + + align:start position:0% +all have to have the same edge length +so for example if you had + + align:start position:0% +so for example if you had + + + align:start position:0% +so for example if you had +you know a uh this is if you had an + + align:start position:0% +you know a uh this is if you had an + + + align:start position:0% +you know a uh this is if you had an +object + + align:start position:0% +object + + + align:start position:0% +object +where you're mixing triangles and + + align:start position:0% +where you're mixing triangles and + + + align:start position:0% +where you're mixing triangles and +squares + + align:start position:0% +squares + + + align:start position:0% +squares +since they have edging matrix + + align:start position:0% +since they have edging matrix + + + align:start position:0% +since they have edging matrix +edge length the facet area is different + + align:start position:0% +edge length the facet area is different + + + align:start position:0% +edge length the facet area is different +and you know there's obviously some + + align:start position:0% +and you know there's obviously some + + + align:start position:0% +and you know there's obviously some +formula for + + align:start position:0% +formula for + + + align:start position:0% +formula for +that + + align:start position:0% +that + + + align:start position:0% +that +the area of + + align:start position:0% +the area of + + + align:start position:0% +the area of +regular polygon in terms of the number + + align:start position:0% +regular polygon in terms of the number + + + align:start position:0% +regular polygon in terms of the number +of edges and the edge length + + align:start position:0% +of edges and the edge length + + + align:start position:0% +of edges and the edge length +okay so that means that over here we had + + align:start position:0% +okay so that means that over here we had + + + align:start position:0% +okay so that means that over here we had +equal cells and so it made it very easy + + align:start position:0% +equal cells and so it made it very easy + + + align:start position:0% +equal cells and so it made it very easy +to have a uniform sampling over there + + align:start position:0% +to have a uniform sampling over there + + + align:start position:0% +to have a uniform sampling over there +it's a little bit more tricky because + + align:start position:0% +it's a little bit more tricky because + + + align:start position:0% +it's a little bit more tricky because +now we've got to deal with the fact that + + align:start position:0% +now we've got to deal with the fact that + + + align:start position:0% +now we've got to deal with the fact that +the facets are not equal in area the bet + + align:start position:0% +the facets are not equal in area the bet + + + align:start position:0% +the facets are not equal in area the bet +the good part is that there are more of + + align:start position:0% +the good part is that there are more of + + + align:start position:0% +the good part is that there are more of +them + + align:start position:0% +them + + + align:start position:0% +them +so that's in uh in on the sphere in 3d + + align:start position:0% +so that's in uh in on the sphere in 3d + + + align:start position:0% +so that's in uh in on the sphere in 3d +we're talking about + + align:start position:0% +we're talking about + + + align:start position:0% +we're talking about +a sphere in the 4d and so + + align:start position:0% +a sphere in the 4d and so + + + align:start position:0% +a sphere in the 4d and so +you know plato and archimedes didn't uh + + align:start position:0% +you know plato and archimedes didn't uh + + + align:start position:0% +you know plato and archimedes didn't uh +think too much about those so we can't + + align:start position:0% +think too much about those so we can't + + + align:start position:0% +think too much about those so we can't +resort to them + + align:start position:0% +resort to them + + + align:start position:0% +resort to them +but um + + align:start position:0% + + + + align:start position:0% + +those figures come into play again + + align:start position:0% +those figures come into play again + + + align:start position:0% +those figures come into play again +because + + align:start position:0% +because + + + align:start position:0% +because +in 4d we're talking about rotations + + align:start position:0% +in 4d we're talking about rotations + + + align:start position:0% +in 4d we're talking about rotations +and we we're looking for regular + + align:start position:0% +and we we're looking for regular + + + align:start position:0% +and we we're looking for regular +patterns of + + align:start position:0% +patterns of + + + align:start position:0% +patterns of +rotations + + align:start position:0% +rotations + + + align:start position:0% +rotations +in this space and so + + align:start position:0% +in this space and so + + + align:start position:0% +in this space and so +one way we can think about that is in + + align:start position:0% +one way we can think about that is in + + + align:start position:0% +one way we can think about that is in +in terms of rotations of these objects + + align:start position:0% +in terms of rotations of these objects + + + align:start position:0% +in terms of rotations of these objects +so let's just do one and see see how + + align:start position:0% +so let's just do one and see see how + + + align:start position:0% +so let's just do one and see see how +that goes so the the aim here is again + + align:start position:0% +that goes so the the aim here is again + + + align:start position:0% +that goes so the the aim here is again +to find some methods for uniformly + + align:start position:0% +to find some methods for uniformly + + + align:start position:0% +to find some methods for uniformly +something the space of rotations so that + + align:start position:0% +something the space of rotations so that + + + align:start position:0% +something the space of rotations so that +if say we do a search so we've we've got + + align:start position:0% +if say we do a search so we've we've got + + + align:start position:0% +if say we do a search so we've we've got +this object in a sensor and we have a + + align:start position:0% +this object in a sensor and we have a + + + align:start position:0% +this object in a sensor and we have a +model in the library and we're trying to + + align:start position:0% +model in the library and we're trying to + + + align:start position:0% +model in the library and we're trying to +figure out + + align:start position:0% +figure out + + + align:start position:0% +figure out +is there some way of rotating this to + + align:start position:0% +is there some way of rotating this to + + + align:start position:0% +is there some way of rotating this to +bring it into alignment with that + + align:start position:0% +bring it into alignment with that + + + align:start position:0% +bring it into alignment with that +and that could be part of recognition + + align:start position:0% +and that could be part of recognition + + + align:start position:0% +and that could be part of recognition +that you know we have multiple objects + + align:start position:0% +that you know we have multiple objects + + + align:start position:0% +that you know we have multiple objects +in the library + + align:start position:0% +in the library + + + align:start position:0% +in the library +which of them can we match but of course + + align:start position:0% +which of them can we match but of course + + + align:start position:0% +which of them can we match but of course +we can't match them directly we first + + align:start position:0% +we can't match them directly we first + + + align:start position:0% +we can't match them directly we first +have to get them rotated + + align:start position:0% +have to get them rotated + + + align:start position:0% +have to get them rotated +and then + + align:start position:0% +and then + + + align:start position:0% +and then +how do we pick the rotations + + align:start position:0% +how do we pick the rotations + + + align:start position:0% +how do we pick the rotations +well to be efficient we don't want to be + + align:start position:0% +well to be efficient we don't want to be + + + align:start position:0% +well to be efficient we don't want to be +sampling parts of the rotation space + + align:start position:0% +sampling parts of the rotation space + + + align:start position:0% +sampling parts of the rotation space +more densely than other parts + + align:start position:0% +more densely than other parts + + + align:start position:0% +more densely than other parts +that be you know the equivalent of + + align:start position:0% +that be you know the equivalent of + + + align:start position:0% +that be you know the equivalent of +searching spending all your time + + align:start position:0% +searching spending all your time + + + align:start position:0% +searching spending all your time +searching around the poles + + align:start position:0% +searching around the poles + + + align:start position:0% +searching around the poles +and so we're trying to find a uniform + + align:start position:0% +and so we're trying to find a uniform + + + align:start position:0% +and so we're trying to find a uniform +way of sampling this + + align:start position:0% +way of sampling this + + + align:start position:0% +way of sampling this +slightly hard to imagine the space + + align:start position:0% +slightly hard to imagine the space + + + align:start position:0% +slightly hard to imagine the space +but let's uh + + align:start position:0% +but let's uh + + + align:start position:0% +but let's uh +start simply with the hexahedron + + align:start position:0% + + + + align:start position:0% + +and think about its rotations + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +well first there's the identity + + align:start position:0% + + + + align:start position:0% + +so what i mean by rotations i mean by + + align:start position:0% +so what i mean by rotations i mean by + + + align:start position:0% +so what i mean by rotations i mean by +rotations that you you take the object + + align:start position:0% +rotations that you you take the object + + + align:start position:0% +rotations that you you take the object +then you rotate it and then the + + align:start position:0% +then you rotate it and then the + + + align:start position:0% +then you rotate it and then the +faces line up with the faces and the + + align:start position:0% +faces line up with the faces and the + + + align:start position:0% +faces line up with the faces and the +edges line up with the edges and the + + align:start position:0% +edges line up with the edges and the + + + align:start position:0% +edges line up with the edges and the +vertices line up with the vertices + + align:start position:0% +vertices line up with the vertices + + + align:start position:0% +vertices line up with the vertices +okay so the identity so in terms of + + align:start position:0% +okay so the identity so in terms of + + + align:start position:0% +okay so the identity so in terms of +quaternions + + align:start position:0% +quaternions + + + align:start position:0% +quaternions +that looks like that + + align:start position:0% +that looks like that + + + align:start position:0% +that looks like that +it has a zero vector part and a scalar + + align:start position:0% +it has a zero vector part and a scalar + + + align:start position:0% +it has a zero vector part and a scalar +part of one + + align:start position:0% +part of one + + + align:start position:0% +part of one +then + + align:start position:0% +then + + + align:start position:0% +then +we can think about a rotation let's say + + align:start position:0% +we can think about a rotation let's say + + + align:start position:0% +we can think about a rotation let's say +about + + align:start position:0% +about + + + align:start position:0% +about +x + + align:start position:0% +x + + + align:start position:0% +x +through let's say pi + + align:start position:0% + + + + align:start position:0% + +and so that's going to be let's see + + align:start position:0% +and so that's going to be let's see + + + align:start position:0% +and so that's going to be let's see +cosine pi over 2 is zero + + align:start position:0% +cosine pi over 2 is zero + + + align:start position:0% +cosine pi over 2 is zero +sine pi over 2 is one + + align:start position:0% +sine pi over 2 is one + + + align:start position:0% +sine pi over 2 is one +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +so that's that quaternion + + align:start position:0% +so that's that quaternion + + + align:start position:0% +so that's that quaternion +so that just turns it 180 degrees about + + align:start position:0% +so that just turns it 180 degrees about + + + align:start position:0% +so that just turns it 180 degrees about +the x + + align:start position:0% +the x + + + align:start position:0% +the x +x axis + + align:start position:0% +x axis + + + align:start position:0% +x axis +and naturally i can do the same thing + + align:start position:0% +and naturally i can do the same thing + + + align:start position:0% +and naturally i can do the same thing +about + + align:start position:0% +about + + + align:start position:0% +about +y + + align:start position:0% + + + + align:start position:0% + +so i've already got + + align:start position:0% +so i've already got + + + align:start position:0% +so i've already got +four + + align:start position:0% +four + + + align:start position:0% +four +distinct rotations that line that object + + align:start position:0% +distinct rotations that line that object + + + align:start position:0% +distinct rotations that line that object +up with itself + + align:start position:0% +up with itself + + + align:start position:0% +up with itself +well i don't have to rotate 180 degrees + + align:start position:0% +well i don't have to rotate 180 degrees + + + align:start position:0% +well i don't have to rotate 180 degrees +oh how about minus 180 degrees + + align:start position:0% +oh how about minus 180 degrees + + + align:start position:0% +oh how about minus 180 degrees +well of course that's the same right so + + align:start position:0% +well of course that's the same right so + + + align:start position:0% +well of course that's the same right so +that that doesn't add anything but i + + align:start position:0% +that that doesn't add anything but i + + + align:start position:0% +that that doesn't add anything but i +could think about rotating pi over two + + align:start position:0% +could think about rotating pi over two + + + align:start position:0% +could think about rotating pi over two +so let's try that + + align:start position:0% +so let's try that + + + align:start position:0% +so let's try that +so pi over 2 that's going to be cosine + + align:start position:0% +so pi over 2 that's going to be cosine + + + align:start position:0% +so pi over 2 that's going to be cosine +of pi over 4 which is 1 over square root + + align:start position:0% +of pi over 4 which is 1 over square root + + + align:start position:0% +of pi over 4 which is 1 over square root +of 2. + + align:start position:0% + + + + align:start position:0% + +so i get that + + align:start position:0% +so i get that + + + align:start position:0% +so i get that +and now here i could talk about minus pi + + align:start position:0% +and now here i could talk about minus pi + + + align:start position:0% +and now here i could talk about minus pi +over two + + align:start position:0% + + + + align:start position:0% + +right because these these two aren't the + + align:start position:0% +right because these these two aren't the + + + align:start position:0% +right because these these two aren't the +same + + align:start position:0% +same + + + align:start position:0% +same +this one is not the negative of that + + align:start position:0% +this one is not the negative of that + + + align:start position:0% +this one is not the negative of that +because the + + align:start position:0% +because the + + + align:start position:0% +because the +real part hasn't changed sign whereas + + align:start position:0% +real part hasn't changed sign whereas + + + align:start position:0% +real part hasn't changed sign whereas +with these guys if i flip the sign of x + + align:start position:0% +with these guys if i flip the sign of x + + + align:start position:0% +with these guys if i flip the sign of x +i get a different quaternion but + + align:start position:0% +i get a different quaternion but + + + align:start position:0% +i get a different quaternion but +remember + + align:start position:0% +remember + + + align:start position:0% +remember +minus q is the same rotation as plus q + + align:start position:0% +minus q is the same rotation as plus q + + + align:start position:0% +minus q is the same rotation as plus q +so i flip the sign of that to get a + + align:start position:0% +so i flip the sign of that to get a + + + align:start position:0% +so i flip the sign of that to get a +different quaternion but it's the same + + align:start position:0% +different quaternion but it's the same + + + align:start position:0% +different quaternion but it's the same +rotation + + align:start position:0% + + + + align:start position:0% + +okay so i can do this for + + align:start position:0% +okay so i can do this for + + + align:start position:0% +okay so i can do this for +x y + + align:start position:0% +x y + + + align:start position:0% +x y +and then i can do it for z + + align:start position:0% +and then i can do it for z + + + align:start position:0% +and then i can do it for z +so i get six of those + + align:start position:0% +so i get six of those + + + align:start position:0% +so i get six of those +uh we've got four there + + align:start position:0% + + + + align:start position:0% + +so we have + + align:start position:0% +so we have + + + align:start position:0% +so we have +10 rotations + + align:start position:0% +10 rotations + + + align:start position:0% +10 rotations +10 samples of the space that we're + + align:start position:0% +10 samples of the space that we're + + + align:start position:0% +10 samples of the space that we're +interested in and so question is you + + align:start position:0% +interested in and so question is you + + + align:start position:0% +interested in and so question is you +know are they more + + align:start position:0% +know are they more + + + align:start position:0% +know are they more +and they're kind of two different ways + + align:start position:0% +and they're kind of two different ways + + + align:start position:0% +and they're kind of two different ways +to proceed the one is sort of + + align:start position:0% +to proceed the one is sort of + + + align:start position:0% +to proceed the one is sort of +geometrically you know look at the + + align:start position:0% +geometrically you know look at the + + + align:start position:0% +geometrically you know look at the +diagram how many other ways can i rotate + + align:start position:0% +diagram how many other ways can i rotate + + + align:start position:0% +diagram how many other ways can i rotate +it + + align:start position:0% +it + + + align:start position:0% +it +and the other one is to + + align:start position:0% +and the other one is to + + + align:start position:0% +and the other one is to +just think of this as a exercise in + + align:start position:0% +just think of this as a exercise in + + + align:start position:0% +just think of this as a exercise in +quaternion multiplication + + align:start position:0% +quaternion multiplication + + + align:start position:0% +quaternion multiplication +so + + align:start position:0% +so + + + align:start position:0% +so +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +let's just do one of those + + align:start position:0% +let's just do one of those + + + align:start position:0% +let's just do one of those +so for example i could pull out + + align:start position:0% +so for example i could pull out + + + align:start position:0% +so for example i could pull out +of that table you know i can + + align:start position:0% +of that table you know i can + + + align:start position:0% +of that table you know i can +now i can try and generate the whole + + align:start position:0% +now i can try and generate the whole + + + align:start position:0% +now i can try and generate the whole +group + + align:start position:0% +group + + + align:start position:0% +group +just by + + align:start position:0% +just by + + + align:start position:0% +just by +multiplication take what i've got take + + align:start position:0% +multiplication take what i've got take + + + align:start position:0% +multiplication take what i've got take +two pairs let's take + + align:start position:0% +two pairs let's take + + + align:start position:0% +two pairs let's take +because it's not very interesting taking + + align:start position:0% +because it's not very interesting taking + + + align:start position:0% +because it's not very interesting taking +the identity but so let's take something + + align:start position:0% +the identity but so let's take something + + + align:start position:0% +the identity but so let's take something +else + + align:start position:0% +else + + + align:start position:0% +else +okay according to our rules for + + align:start position:0% +okay according to our rules for + + + align:start position:0% +okay according to our rules for +multiplication i get 0 minus + + align:start position:0% +multiplication i get 0 minus + + + align:start position:0% +multiplication i get 0 minus +x dot y + + align:start position:0% +x dot y + + + align:start position:0% +x dot y +which is zero + + align:start position:0% +which is zero + + + align:start position:0% +which is zero +and then we get zero times x plus zero + + align:start position:0% +and then we get zero times x plus zero + + + align:start position:0% +and then we get zero times x plus zero +times y + + align:start position:0% +times y + + + align:start position:0% +times y +plus x cross y + + align:start position:0% +plus x cross y + + + align:start position:0% +plus x cross y +and so that's + + align:start position:0% +and so that's + + + align:start position:0% +and so that's +zero and + + align:start position:0% +zero and + + + align:start position:0% +zero and +minus z + + align:start position:0% +minus z + + + align:start position:0% +minus z +hmm uh no + + align:start position:0% +hmm uh no + + + align:start position:0% +hmm uh no +well that's already in the table right + + align:start position:0% +well that's already in the table right + + + align:start position:0% +well that's already in the table right +so um + + align:start position:0% +so um + + + align:start position:0% +so um +so that doesn't add uh to the table so + + align:start position:0% +so that doesn't add uh to the table so + + + align:start position:0% +so that doesn't add uh to the table so +let's take something else + + align:start position:0% +let's take something else + + + align:start position:0% +let's take something else +let's take uh some of these 1 over + + align:start position:0% +let's take uh some of these 1 over + + + align:start position:0% +let's take uh some of these 1 over +square root of 2 + + align:start position:0% +square root of 2 + + + align:start position:0% +square root of 2 +1 x 1 over square root of 2 + + align:start position:0% +1 x 1 over square root of 2 + + + align:start position:0% +1 x 1 over square root of 2 +1 y + + align:start position:0% +1 y + + + align:start position:0% +1 y +ok that's going to be more interesting 1 + + align:start position:0% +ok that's going to be more interesting 1 + + + align:start position:0% +ok that's going to be more interesting 1 +times 1 is 1 + + align:start position:0% +times 1 is 1 + + + align:start position:0% +times 1 is 1 +minus x dot y is zero + + align:start position:0% +minus x dot y is zero + + + align:start position:0% +minus x dot y is zero +and our the one over square root of two + + align:start position:0% +and our the one over square root of two + + + align:start position:0% +and our the one over square root of two +gives us + + align:start position:0% +gives us + + + align:start position:0% +gives us +one half + + align:start position:0% +one half + + + align:start position:0% +one half +and then the vector part is one times y + + align:start position:0% +and then the vector part is one times y + + + align:start position:0% +and then the vector part is one times y +plus one times x + + align:start position:0% +plus one times x + + + align:start position:0% +plus one times x +plus + + align:start position:0% + + + + align:start position:0% + +x cross y + + align:start position:0% + + + + align:start position:0% + +so that's one half + + align:start position:0% +so that's one half + + + align:start position:0% +so that's one half +one + + align:start position:0% +one + + + align:start position:0% +one +and + + align:start position:0% +and + + + align:start position:0% +and +x hat + + align:start position:0% +x hat + + + align:start position:0% +x hat +y + + align:start position:0% +y + + + align:start position:0% +y +plus x hat y hat t hat + + align:start position:0% +plus x hat y hat t hat + + + align:start position:0% +plus x hat y hat t hat +so that's a new one + + align:start position:0% +so that's a new one + + + align:start position:0% +so that's a new one +so the axis of rotation + + align:start position:0% +so the axis of rotation + + + align:start position:0% +so the axis of rotation +is uh 1 1 1 + + align:start position:0% +is uh 1 1 1 + + + align:start position:0% +is uh 1 1 1 +and if you want to make it the unit + + align:start position:0% +and if you want to make it the unit + + + align:start position:0% +and if you want to make it the unit +vector it's 1 over square root of 3 + + align:start position:0% + + + + align:start position:0% + +and that's not not in this table + + align:start position:0% +and that's not not in this table + + + align:start position:0% +and that's not not in this table +and the angle is cosine theta over 2 is + + align:start position:0% +and the angle is cosine theta over 2 is + + + align:start position:0% +and the angle is cosine theta over 2 is +a half + + align:start position:0% +a half + + + align:start position:0% +a half +so + + align:start position:0% +so + + + align:start position:0% +so +let's see that means + + align:start position:0% +let's see that means + + + align:start position:0% +let's see that means +theta over 2 is + + align:start position:0% +theta over 2 is + + + align:start position:0% +theta over 2 is +pi over 3 + + align:start position:0% +pi over 3 + + + align:start position:0% +pi over 3 +so theta is 2 pi over 3. + + align:start position:0% +so theta is 2 pi over 3. + + + align:start position:0% +so theta is 2 pi over 3. +so that's an interesting + + align:start position:0% +so that's an interesting + + + align:start position:0% +so that's an interesting +new rotation + + align:start position:0% +new rotation + + + align:start position:0% +new rotation +um + + align:start position:0% +um + + + align:start position:0% +um +if you look at the cube + + align:start position:0% +if you look at the cube + + + align:start position:0% +if you look at the cube +that corresponds to one of its corners + + align:start position:0% +that corresponds to one of its corners + + + align:start position:0% +that corresponds to one of its corners +so we're taking this the origin and + + align:start position:0% +so we're taking this the origin and + + + align:start position:0% +so we're taking this the origin and +connecting it to a corner + + align:start position:0% +connecting it to a corner + + + align:start position:0% +connecting it to a corner +so that's the axis + + align:start position:0% +so that's the axis + + + align:start position:0% +so that's the axis +and we're rotating by + + align:start position:0% +and we're rotating by + + + align:start position:0% +and we're rotating by +120 degrees + + align:start position:0% +120 degrees + + + align:start position:0% +120 degrees +and you can see that that's a rotation + + align:start position:0% +and you can see that that's a rotation + + + align:start position:0% +and you can see that that's a rotation +of the cube that does bring us back into + + align:start position:0% +of the cube that does bring us back into + + + align:start position:0% +of the cube that does bring us back into +alignment with ourselves right if you + + align:start position:0% +alignment with ourselves right if you + + + align:start position:0% +alignment with ourselves right if you +rotate 120 degrees about that axis + + align:start position:0% +rotate 120 degrees about that axis + + + align:start position:0% +rotate 120 degrees about that axis +everything falls back into place and so + + align:start position:0% +everything falls back into place and so + + + align:start position:0% +everything falls back into place and so +we're just about out of time but + + align:start position:0% + + + + align:start position:0% + +we can proceed two ways the one is you + + align:start position:0% +we can proceed two ways the one is you + + + align:start position:0% +we can proceed two ways the one is you +know look at that example and some + + align:start position:0% +know look at that example and some + + + align:start position:0% +know look at that example and some +others and we get a total of 24 + + align:start position:0% +others and we get a total of 24 + + + align:start position:0% +others and we get a total of 24 +rotations + + align:start position:0% +rotations + + + align:start position:0% +rotations +or we can + + align:start position:0% +or we can + + + align:start position:0% +or we can +if we're more mathematically inclined we + + align:start position:0% +if we're more mathematically inclined we + + + align:start position:0% +if we're more mathematically inclined we +can go this way + + align:start position:0% +can go this way + + + align:start position:0% +can go this way +or you can you know it's fun to write a + + align:start position:0% +or you can you know it's fun to write a + + + align:start position:0% +or you can you know it's fun to write a +little program that just implements + + align:start position:0% +little program that just implements + + + align:start position:0% +little program that just implements +quaternion multiplication and then + + align:start position:0% +quaternion multiplication and then + + + align:start position:0% +quaternion multiplication and then +builds this uh table by taking pairwise + + align:start position:0% +builds this uh table by taking pairwise + + + align:start position:0% +builds this uh table by taking pairwise +products and seeing whether you get + + align:start position:0% +products and seeing whether you get + + + align:start position:0% +products and seeing whether you get +something new + + align:start position:0% +something new + + + align:start position:0% +something new +and eventually you'll run out and you'll + + align:start position:0% +and eventually you'll run out and you'll + + + align:start position:0% +and eventually you'll run out and you'll +have 24 of them at that point + + align:start position:0% +have 24 of them at that point + + + align:start position:0% +have 24 of them at that point +okay next time we'll start talking about + + align:start position:0% +okay next time we'll start talking about + + + align:start position:0% +okay next time we'll start talking about +relative orientation which is more + + align:start position:0% +relative orientation which is more + + + align:start position:0% +relative orientation which is more +relevant to + + align:start position:0% +relevant to + + + align:start position:0% +relevant to +binocular visions \ No newline at end of file diff --git a/kwbDWPrPfQI.txt b/kwbDWPrPfQI.txt new file mode 100644 index 0000000000000000000000000000000000000000..6b2e0cb080f081ef83ec91fdd465f50638ce0050 --- /dev/null +++ b/kwbDWPrPfQI.txt @@ -0,0 +1,291 @@ +align:start position:0% + +if our objective is to keep the mean + + align:start position:0% +if our objective is to keep the mean + + + align:start position:0% +if our objective is to keep the mean +squared estimation error small then the + + align:start position:0% +squared estimation error small then the + + + align:start position:0% +squared estimation error small then the +best possible estimator is the + + align:start position:0% +best possible estimator is the + + + align:start position:0% +best possible estimator is the +conditional expectation but sometimes + + align:start position:0% +conditional expectation but sometimes + + + align:start position:0% +conditional expectation but sometimes +the conditional expectation is hard to + + align:start position:0% +the conditional expectation is hard to + + + align:start position:0% +the conditional expectation is hard to +calculate maybe we're missing the + + align:start position:0% +calculate maybe we're missing the + + + align:start position:0% +calculate maybe we're missing the +details of the various probability + + align:start position:0% +details of the various probability + + + align:start position:0% +details of the various probability +distributions or maybe we have all the + + align:start position:0% +distributions or maybe we have all the + + + align:start position:0% +distributions or maybe we have all the +distributions that we need but the + + align:start position:0% +distributions that we need but the + + + align:start position:0% +distributions that we need but the +formulas are complicated + + align:start position:0% +formulas are complicated + + + align:start position:0% +formulas are complicated +after all the conditional expectation + + align:start position:0% +after all the conditional expectation + + + align:start position:0% +after all the conditional expectation +can be a complicated nonlinear function + + align:start position:0% +can be a complicated nonlinear function + + + align:start position:0% +can be a complicated nonlinear function +of the observations for this reason we + + align:start position:0% +of the observations for this reason we + + + align:start position:0% +of the observations for this reason we +may want to consider an estimator that + + align:start position:0% +may want to consider an estimator that + + + align:start position:0% +may want to consider an estimator that +has a simpler structure an estimator + + align:start position:0% +has a simpler structure an estimator + + + align:start position:0% +has a simpler structure an estimator +that is a linear function of the data + + align:start position:0% +that is a linear function of the data + + + align:start position:0% +that is a linear function of the data +and then within this class of estimators + + align:start position:0% +and then within this class of estimators + + + align:start position:0% +and then within this class of estimators +find the one that results in the + + align:start position:0% +find the one that results in the + + + align:start position:0% +find the one that results in the +smallest possible mean squared error in + + align:start position:0% +smallest possible mean squared error in + + + align:start position:0% +smallest possible mean squared error in +this lecture we will formulate this + + align:start position:0% +this lecture we will formulate this + + + align:start position:0% +this lecture we will formulate this +linear least squares estimation problem + + align:start position:0% +linear least squares estimation problem + + + align:start position:0% +linear least squares estimation problem +and then solve it we will see that the + + align:start position:0% +and then solve it we will see that the + + + align:start position:0% +and then solve it we will see that the +solution is given by a simple formula + + align:start position:0% +solution is given by a simple formula + + + align:start position:0% +solution is given by a simple formula +that involves only the means variances + + align:start position:0% +that involves only the means variances + + + align:start position:0% +that involves only the means variances +and covariances of the random variables + + align:start position:0% +and covariances of the random variables + + + align:start position:0% +and covariances of the random variables +involved because of the simplicity of + + align:start position:0% +involved because of the simplicity of + + + align:start position:0% +involved because of the simplicity of +the method linear estimators are used + + align:start position:0% +the method linear estimators are used + + + align:start position:0% +the method linear estimators are used +quite often especially in systems where + + align:start position:0% +quite often especially in systems where + + + align:start position:0% +quite often especially in systems where +estimates need to be computed quickly in + + align:start position:0% +estimates need to be computed quickly in + + + align:start position:0% +estimates need to be computed quickly in +real time as observations are obtained + + align:start position:0% +real time as observations are obtained + + + align:start position:0% +real time as observations are obtained +we will look into some of the + + align:start position:0% +we will look into some of the + + + align:start position:0% +we will look into some of the +mathematical properties of the linear + + align:start position:0% +mathematical properties of the linear + + + align:start position:0% +mathematical properties of the linear +least mean squares estimator and The + + align:start position:0% +least mean squares estimator and The + + + align:start position:0% +least mean squares estimator and The +Associated mean squared error revisit an + + align:start position:0% +Associated mean squared error revisit an + + + align:start position:0% +Associated mean squared error revisit an +example from the previous lecture and + + align:start position:0% +example from the previous lecture and + + + align:start position:0% +example from the previous lecture and +finally close with some comments on the + + align:start position:0% +finally close with some comments on the + + + align:start position:0% +finally close with some comments on the +ways that this estimator can be used \ No newline at end of file diff --git a/l8GqOCN8M-w.txt b/l8GqOCN8M-w.txt new file mode 100644 index 0000000000000000000000000000000000000000..f4d978e770f4401fcbcc7d08a79e06a6f986e21c --- /dev/null +++ b/l8GqOCN8M-w.txt @@ -0,0 +1,4051 @@ +The following content is +provided under a Creative + +Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high quality educational +resources for free. + +To make a donation or view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu. + +PROFESSOR: OK, so by this time, +most of you should have + +had your meetings with +your masters. + +How many of you had meetings +with your masters? + +Who didn't yet? + +AUDIENCE: Today. + +PROFESSOR: Today? + +And Friday. + +Who hasn't scheduled +a meeting? + +So are you talking to them, +and do you know-- + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: OK, make sure you get +masters meetings scheduled + +because this is a very +important part. + +We are getting feedback +from the masters. + +I think they are giving you guys +a lot of good advice, and + +so make sure you schedule, you +go, you meet, get that result, + +use that result. + +It's very hard to arrange that +kind of a senior person + +spending a lot of time +with only two of + +you at a given time. + +That's a really good ratio +to have, so take + +advantage of that. + +OK, so also, I think at this +point, most of the beta issues + +for project one, we have been +probably worked with, and they + +have some issues some people +looked at that they are + +performance code. + +They were not happy because +the thing is this. + +You can always run everything +instantaneously if it doesn't + +have to produce a +correct answer. + +You can just return, and so part +of performance is also it + +has to have some correctness. + +So certain amount of correctness +has to be passed + +before we can give +performer grade. + +So some people have +this question. + +Why are you giving me a +correctness grade because it + +seemed to run? + +But if you haven't done the +right checks and stuff like + +that, then it's unfair for other +people because there's + +no way people who do the correct +implementation can + +match that performance +because we're using + +that as upper bound. + +So make sure you do that. + +And another issue people had +was when you go to masters, + +you're going to work with one +or two other students. + +And in your group, you're +going to share all the + +material with your group +member and nobody else. + +But between the beta and final, +you get opportunity to + +basically get input from your +masters, and also see what the + +other people who are coming +to a project in your + +discussion have done. + +So it's OK for you to +see those code. + +You can't take the code home. + +You can't just say give me a +print-out, I am going to take + +home and re-implement. + +That doesn't count, but if you +see some clever things they + +have done, it's all +here to learn. + +Class is all the mostly +about learning. + +However we have to grade you, so +it's not all about grading, + +it's about learning. + +So we are trying to get a +balance where we opportunity + +for you to learn from +your peers. + +So if you go look at other +people's code, if you find + +something cool they +have done, learn. + +And also if you [UNINTELLIGIBLE] + +for you [UNINTELLIGIBLE] + +say, look, I did +something cool. + +It's a good learning experience +in there, so that's + +one opportunity you have to talk +to other people on other + +groups, to basically learn +something or find some + +interesting tidbits of how +to get good performance. + +And hopefully, you learn some +interesting things and able to + +implement that in your final. + +OK? + +So today we are going to talk +about memory systems and + +performance engineering. + +So if you look at basic idea +of what memory systems, you + +want to build a computer +that seemed to have + +a really fast memory. + +You don't want things +to be slow. + +For example, a long time ago, +people build these computers + +where memory's always slow, +everything [UNINTELLIGIBLE] + +further away. + +It doesn't help anybody. + +The way we know how to do that +is to build small amount of + +memory very close to +the processor. + +You can't build a huge amount +of things all close to you. + +That doesn't work, doesn't +scale like that. + +And we made a cache just like +that, and you build larger and + +larger memory [UNINTELLIGIBLE] +going down, and the illusion + +is you want to give the illusion +of you have huge + +amount of memory. + +Everybody's very close to you. + +OK, so it looks like you have +millions of friends, that you + +talk to everybody, and +that doesn't happen. + +But how do you give +that illusion? + +And the way that you give that +illusion is when you use + +normal programming practice, +when you normally using data, + +people have found there +are two properties. + +The first thing is called +temporal locality. + +That means if I use some data +item, there's a good chance I + +use that data item +again very soon. + +There is something I haven't +used for a long time, probably + +has a good chance I will +not use it for a + +very, very long time. + +So can I take advantage +of temporal locality? + +So that mean some data will be +get for use a lot of time, in + +a very quick [UNINTELLIGIBLE], +so those things should be very + +near to you because you might. + +Other one is spatial locality. + +That means if I use some data +item, there's a good chance + +you'll be using data items next +to that, closer to that. + +So can we take advantage +of that? + +So those two properties help you +help the compiler to fool + +the system, fool everybody, +thinking that it has this huge + +amount of memory very close to +you, but internally doesn't. + +Unfortunately, since it's trying +to fool you, it doesn't + +work all the time, and when it +doesn't work, it's good to + +recognize and able to +fix those things. + +So I showed this picture +sometime ago, too. + +Memories in a big hierarchy. + +L1, L2, in fact, we have L3 +cache and a memory, disk, + +tapes, it can go up and down. + +And the key thing is when you go +here, you're starting from + +registers, you have very +small amount of + +things, very fast access. + +Here, we have almost +infinite amount of + +things, very slow access. + +And the two reasons why this has +to be smart because first + +of all, those things +are very expensive. + +And second of course, you can't +[UNINTELLIGIBLE] too + +much, and when you go down, +things get somewhat cheaper. + +So that was one of the kind of +economic incentive here. + +So I talked about cache issues, +and I'm going to go + +through this again because we +are really going to dig deep + +into these things. + +So when you have a cache, that +means you have a small memory + +close to you that's basically +shadowing something sitting + +behind you. + +So when you ask for the data in +the cache, there are many + +reasons why it's not there. + +First thing is cold miss. + +What that means is you're asking +for something that you + +have never asked before. + +It's the first time you're +asking, so the data is + +probably sitting way behind +in your memory where, + +[UNINTELLIGIBLE] + +in a disk. + +We haven't even loaded +it in there. + +And the first time you have to +get it, so that get pulled in, + +and so this seems to be a place +where there's nothing + +you can do. + +But another part of locality is +a thing called prefetching. + +These modern processors +have a crystal ball. + +They carry most of the things +that branch prediction and + +stuff is trying to predict +what you want to do. + +You can do the same +thing in memory. + +You can look at what +you have done. + +And Intel has this huge amount +of circuitry that they don't + +tell anybody what they do, but +they're trying to predict what + +you might fetch next, what data +you might look for next. + +And if it is working well, +something you had never, ever + +looked before, it might deduce +that you might need it and go + +get it for you. + +So if that works, great. + +So then there's thing called +capacity miss. + +What that means is as I said, +I am trying to keep my best + +friends, or the people I will +be working with a lot-- + +Oh, nice. + +What's going on here? + +Please start later. + +OK. + +--the people I'm going to work +a lot with, close to me. + +The problem is I can have only +certain number of friends, and + +if you have more than that, +I can't keep everybody. + +So hopefully, your program is +going to use a lot what we + +call the working set that +can fit in the cache. + +And at that point, you get all +of those people, like I said, + +get everybody into one room, +and the problem is if your + +party spills over from +the room, then + +there's a lot of issues. + +But if everybody fits in the +room, things are very nice. + +You can have a good interaction, +continuous + +interaction, with them. + +And what happens is, if not, the +worst case is the caches + +have eviction policy, normally +is called least recently used. + +That means if I don't have room +in the cache, I figure + +out the cache line that I +haven't touched for longest, + +and I get rid of that, +bring the next one. + +So that's a good policy. + +It fits in your locality +thing, but when + +will did not work? + +[UNINTELLIGIBLE] + +going to figure out when least +recently used will create a + +really bad problem +in capacity. + +AUDIENCE: [INAUDIBLE] + +just one. + +Say you're [INAUDIBLE] set, +and that set is, by one, + +bigger than the [INAUDIBLE] + +missing. + +PROFESSOR: Very good. + +So what you're going through, +you're going round some data + +again and again, and that amount +of data is one bigger + +than your cache line. + +You are going to have +no locality because + +[UNINTELLIGIBLE], and when you +go to, just before you use + +that data, they said, oops, I +need to bring one more data. + +I need to evict something, and +who am I going to evict? + +The guy I'm going to use next +because it was the least + +recently used thing. + +So it goes, and then you go +there, and you bring that. + +Who's it going to evict? + +You're going to evict the +one I just brought. + +You're going to evict the next +one that I am just about to + +use and bring that one. + +And you go use that, and then +to use the next one, you're + +going evict the one you're +just about to use. + +So by going and doing that, you +basically get no locality. + +So that's a really bad +problem in here. + +So another interesting thing is +called a conflict misses. + +Conflict misses says normally, +when you have a cache-- + +so what we have is you have +this large storage, which + +[UNINTELLIGIBLE] + +the memory, you're going to map +into smaller storage in + +here, which is cache. + +So one way to say is any of +this value line can be + +anywhere here. + +That's called fully +associative cache. + +Implementing that is somewhat +complicated, so the other + +extreme is called direct +map cache. + +What that means is this segment, +the same size here, + +can map into here, and then +the next segment also + +can map into here. + +That means if you get this cache +line here, it can be + +only mapped into one +place in this here. + +This cache line can only be +here, and also this cache line + +can also only be here if +it is the same offset. + +So that means for every cache +line, there's only one + +location in the cache. + +So here, what would be +really sad scenario? + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: Yeah, I mean +I assume I have a + +lot of these slots. + +I read something here, and the +next time I read something + +here, next time I read something +here, and I go round + +and round this way. + +I might be touching only very +few number of data items, but + +they also mapping into one +cache line even though my + +working set is very small +than the cache. + +I still don't have +any cache usage + +because I am having conflicts. + +And then there are two other +misses when you're going to + +multi-process. + +We'll go through them +in later lectures. + +One is called true sharing. + +That means there are caches +private to each core, and what + +happens is if one core uses some +data, you've have to get + +the cache line there. + +If the other core wants to use +that data, you have to bring + +the cache line back there, and +the cache lines can ping-pong + +[UNINTELLIGIBLE] that. + +False sharing is even +a worst way. + +So what happens is if the first +processor here touches + +this value of the cache line, +second processor touches this + +value of the cache line. + +We're not sharing anything, +but unfortunately, the two + +things I'm using sits next to +each other, so when I ride + +this thing, I get the cache +line, he doesn't. + +When he need to ride this +thing, he has to + +get the cache line. + +So I am seemingly using +independent data, but I am + +bouncing cache line in between, +and if that happened, + +that going to have a huge +big performance impact. + +So these other things. + +The last two, we'll get +to a little bit later. + +So today I am going to start +with modeling how caches work + +with a very simplistic cache. + +So here's, assume, my cache. + +I have 32 kilobytes in here. + +This is a direct map cache. + +That means that in my memory, 32 +kilobyte chucks get mapped + +to direct [UNINTELLIGIBLE]. + +This 32 kilobyte get +mapped here. + +That 32 kilobyte get +mapped here. + +And the cache line inside is 64 +bytes, 64, and that means I + +have basically +[UNINTELLIGIBLE PHRASE]. + +32 kilobyte in here. + +OK? + +So just remember this as we go +on doing this, we will use + +this as a formula. + +OK? + +And we assume if you getting +the cache, [UNINTELLIGIBLE] + +single cycle, if you +miss 100 cycles. + +OK, so it's nice numbers +to do that. + +And so the first thing is we +have a reference like this. + +OK? + +You go from [i] equals 0 to +[i] less than very large + +number, A[i]. + +I just go to accessing memory +like one after another after + +another after another. + +So you see how this is +going on in here? + +So also I am accessing integers, +so that means four + +bytes at a time in cache line. + +So what happens here? + +So I assume size of int is four, +so you're getting four + +bytes in here. + +So yeah, you're doing s reads +to A. I'm accessing + +s elements in here. + +And you have 16 elements +of a per cache line. + +OK, you see why 16 if there? + +Because I have 64 in here, +64 bytes in here. + +Each time axises four bytes, +so I have 16 of integers in + +cache line. + +AUDIENCE: [INAUDIBLE] + +bits or bytes? + +PROFESSOR: Bytes. + +Byte. + +Did I say bits? + +No, bytes. + +So what happens is if it axises +the same element, 15 of + +every 16 is in the cache because +when we are going one + +after the first guy, cache miss, +I had to go bring it, + +and the next 15, I have +brought to it. + +It's in the cache. + +So what should be my cost? + +[UNINTELLIGIBLE] + +cost of memory access. + +I am accessing s data, and +1/16th of that is a cache + +miss, 15/16th is a cache hit. + +So basically total +[UNINTELLIGIBLE] + +is a 15/16th of s is a cache +hit, and other 1/16th I have + +100 times cycles I need because +it's a cache miss. + +Everybody good so far? + +OK, so what type of locality +do we have here? + +First of all, do we +have locality? + +Who thinks we have locality? + +OK, lot of people thinks +we have locality. + +What type? + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: Spatial locality +because what we are doing is + +we are accessing the nearby +elements even though we are + +not getting back any of the +data yet, so we get some + +spacial locality axis here. + +That's good, so this is our +very -- most simple + +thing we can do. + +So what kind of misses are we +going to have in the cache? + +Cold misses. + +I'm missing because I have never +seen that data before, + +so it's a cold miss in here. + +OK, so that's that. + +Let's look at this one. + +I'm accessing A[0] + +s times. + +OK? + +What's the total access time? + +How many cache misses +am I going to get? + +One, so I basically have 100 +time for the first cache miss, + +and s minus 1 for the rest +basically it's a hit. + +OK? + +That's good, so what kind +of locality's this? + +Spatial or temporal. + +There's not too many choices. + +Or none. + +How many people think spatial? + +How many people think +temporal? + +How many people said there's +none locality? + +OK, that's a lot of temporal. + +OK, you want to get +[UNINTELLIGIBLE]. + +That's temporal locality here +because you're accessing to + +the same thing again and again +and again, same data. + +So this is-- + +Oh, OK. + +Want to restart, OK. + +Wait a little. + +So this is only time we +notice in a hurry. + +Every time, I go to do +something, I get hourglass. + +So what kind of misses +are we getting? + +Trick question. + +I got one cold miss, and +that's about it. + +And the rest I don't +have any misses. + +So if I have a miss, +it's a cold miss. + +OK, so here I am doing something +interesting. + +So what the heck is +in this list? + +So I'm accessing A[i] + +[UNINTELLIGIBLE] + +this 2 to the power number, +one shifted to the entire + +miss, 2 to the power N. I +shifted between 4 and 13. + +What this 13? + +Why is 13? + +Less than 13. + +What's 2 the power of 13? + +I think I got this right. + +AUDIENCE: 8,192. + +PROFESSOR: What's 2 to +the power of 13? + +AUDIENCE: 8,192. + +PROFESSOR: Yeah, 8K. + +And I have 32K. + +So 8K of 32 [UNINTELLIGIBLE]. + +8K of integers, which is each +as 4 bytes is how much? + +32K. + +So what this says is everything +I access should fit + +into the cache. + +I am accessing data like that. + +I'm going back and accessing +data like that. + +I'm going back and accessing +data like that, and it should + +all fit into the cache. + +Do you see what I do? + +I access up to 2 to the power +of 18, and I go back and + +access that again. + +I'm just going back +and back because + +of the model operation. + +Everybody see what's going on? + +So how many cache misses +should I have? + +AUDIENCE: There are four +cache [INAUDIBLE]. + +PROFESSOR: OK, how many cache +lines I would be accessing if + +I am doing i1 2 to +the power N? + +[i] + +mod 2 to the power N. + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: So one miss +for each axis line + +the first time around. + +Afterward, it's only +in the cache. + +So how many axis lines? + +2 to the power N. + +Is that right? + +I think this is wrong. + +Oh, yeah, this is right +because every axis-- + +So in the cache line, +how many-- + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: This is four. + +So there are 16 entries here. + +16 entries in here. + +OK, only one of them basically +misses that, so that means if + +2 to the power N axises-- + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: You are doing 2 to +the power N axises before you + +go back in here. + +So what you're doing +is you are-- + +you make this many axises before +you go back again. + +OK? + +And how many axises assigned to +be in the same cache line? + +You have 64 bytes +in the cache. + +OK each axis is four. + +16. + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: 16. + +So that's true [UNINTELLIGIBLE]. + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: Yeah, but what I'm +saying is I might not access + +the [UNINTELLIGIBLE] + +because if any small. + +I only access a certain amount +of cache line, so I'm + +accessing a part of the cache. + +I might not go through the-- +can everybody see this, how + +this is working? + +Because if I'm only accessing, +we'll say, accessing one, if + +this is, we'll say, 2 +to the power of 5. + +OK, I am not going to access +the entire cache line. + +[UNINTELLIGIBLE] + +cache is I'm going to +[UNINTELLIGIBLE] + +go through the cache. + +So this many cache lines +I'm accessing. + +OK, and the first time I access +that, I get a cache + +miss, and after that, it say +everything is in the cache. + +Everybody's following me? + +Or are we like lost in here? + +How many people are lost? + +OK, let's do this. + +So what happens is if you have +a modular 2 to the power N. + +What that means is I'm going +to keep accessing one to + +somewhere 2 to the power N, and +the next one, I am going + +back here again. + +That's my axises, basically, +because it goes + +[UNINTELLIGIBLE] + +accessing to the power of N. + +I nicely said n is +between 4 and 13. + +So n is 13 means the maximum +I can do is 8K. + +8K increase. + +8K increase equals 32K +kilobytes of memory. + +So that means you don't +have any option of + +overwriting the cache. + +So you go to cache, +[UNINTELLIGIBLE]. + +You don't wrap around +in the cache. + +Do you see that? + +OK, you know wrap arounding is +so bad, that means all these + +things is going to fit in the +cache, and then when you get + +[UNINTELLIGIBLE], this is +going to be in the cache + +because the data you access is +smaller than the entire cache. + +OK, so what that means is only +the first line has to have + +some cache misses. + +So how many cache misses +you are going to have + +in the first line? + +Or any of the lines going to +have cache misses because the + +first line still fit +in the cache. + +[UNINTELLIGIBLE] + +anything. + +We don't need everything. + +How many cache misses +have in here? + +The interesting thing is because +these are four bytes, + +we have a 64-byte cache line, +and each is four bytes. + +So that means I can do 16 axises +every time I have a + +cache miss. + +OK, so up to here to here is 2 +to the N. My cache misses I do + +[UNINTELLIGIBLE] + +basically. + +My cache misses is basically +this much. + +Everything else is in the cache, +and after the first + +line, everything else is +in the cache again, + +[UNINTELLIGIBLE] nicely, +got my working set + +to fit in the cache. + +I'm really happy. + +Everybody see this? + +How many people don't +see it now? + +OK, good. + +So let's move to something a +little bit more complicated. + +What kind of locality +do we have? + +AUDIENCE: Temporal +and spatial. + +PROFESSOR: Good. + +We have temporal and spatial. + +You have spatial because every +time you go, you only get the + +first line of the cache. + +Rest is in the cache. + +From that, I got a 16x +improvement because I have + +temporal locality. + +And since I only access when I +go back to the data, after + +accessing this, since it's +already in the cache, I get + +spatial locality because +of the 16. + +16 things are in the cache, +I am going through that. + +I get spatial locality. + +I get temporal locality because +next time I access, + +it's still in the cache. + +I haven't taken anything +out of the cache. + +OK, what kind of misses? + +Should be cold misses again. + +Cold misses because the first +time I [UNINTELLIGIBLE] + +things. + +I haven't seen that data. + +After I get it, everything +is in the cache. + +So now, here's interesting +case. + +Now, I am doing 2 to the power +N, where N is great than 14. + +Now, what happens? + +Now, what happens in our picture +here is I am going-- + +So as you might cache +is somewhere here. + +At this point, I fill +out the cache. + +I still keep going, and minute +I access something + +[UNINTELLIGIBLE] + +cache, what's going to happen? + +So I went through accessing +34 kilobyte. + +If I access the next +one, what happens? + +OK, no, no, no shutting +down, please. + +OK, what happened? + +So I am accessing more than +I can fit into the cache. + +Next time access, what's +going to happen? + +Anyone want to take +a wild guess? + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: +[UNINTELLIGIBLE PHRASE] + +before that. + +[UNINTELLIGIBLE] + +in there. + +So what happens is then am +I ever going to have any + +temporal locality? + +No. + +OK, so now, first access to +each line basically misses + +forever because by the time +I get back to the + +[UNINTELLIGIBLE], +it's not there. + +So basically, it's gone +out of the cache. + +So what that means is my total +access time is basically every + +16th element, I am getting +cache miss forever. + +So what that means, every 15th +of 16, I have a hit. + +So what I have is 15 out of +16, I have a cache hit. + +1/16th of the time, I have +a cache miss forever. + +So what kind of locality +do I have now? + +I have spatial locality. + +I don't have any temporal +locality. + +I don't ever go back to +something in the cache again. + +So what I have is spatial +locality, so what type of + +misses now do I have? + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: Cold, right. + +AUDIENCE: Is it like +shared misses? + +[INAUDIBLE] + +PROFESSOR: It's not shared. + +When you fill out the cache, +you go back to + +[UNINTELLIGIBLE]. + +You fill the cache. + +So what type of miss is that? + +AUDIENCE: Capacity? + +PROFESSOR: Capacity miss. + +OK, so you have basically +cold and capacity + +misses happening now. + +OK? + +AUDIENCE: One question. + +[INAUDIBLE] + +that you multiplied whenever +you're trying to load from + +memory, is that like an +arbitrary number, or is that + +the actual cost of going-- + +PROFESSOR: Every machine, you +can get this beautiful table. + +I will go off what your +machines have. + +We still have a number saying +this is your miss + +[UNINTELLIGIBLE], this +is the thing-- + +I mean, so some of these things +you realize because of + +all of the complexity. + +It's not that nice and simple, +but this, I just pull out of + +hat, and it's kind of normal. + +So what do I do, now? + +I am doing the mod, but I am +multiplying [i] by 16. + +So now, I am accessing this +value, this value, this value, + +this value in here. + +I'm accessing this value, this +value, this value, this value. + +One value in each cache line. + +OK? + +How much cache misses do you +think I'm going to get? + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: 100 for every access +is basically beginning + +a cache line, you're taking one +value and if I go back to + +that value, I have already +filled up the cache. + +So basically, I have first +access in the cache. + +And what's your total +access time? + +Anyone will take a guess? + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: Yep, 100 times +x because I have no-- + +OK, so this is a +[UNINTELLIGIBLE] + +locality. + +That was clear. + +What kind of misses +am I getting now? + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: Now, I'm getting +conflict misses. + +I get a cold miss at the +beginning, first time around, + +and then every time I do +something, I'm getting + +conflict miss because the thing +is, now, this N, I am + +only accessing small +amount of data. + +It doesn't fit in the cache, but +I'm not still getting any + +kind of sharing, so I'm having +conflict misses. + +[UNINTELLIGIBLE] second +time, I guess I will + +probably jump over this. + +I just did OK, if I go random +access, what happens? + +So let me jump over that. + +Actually can do a calculation +to figure out how many, + +probabilistically, how +much you might have + +and stuff like that. + +OK. + +So now, if you look at what's +going on, when you have no + +locality, you'd have +no locality. + +That's a pretty obvious +statement. + +And then if you have spatial +locality and no temporal + +locality, we are +streaming data. + +That means you are going through +the data, but you're + +not getting back to it +fast enough, so I + +have temporal locality. + +So I stream through data, so +that means I go through data + +in a streaming fashion. + +OK? + +So what we have is if working +set fits in cache, you have + +InCache mode. + +If working set is too big for +cache, you can get some + +streaming mode and still get +some locality because we are + +bringing the lines in here. + +And you can do other things +like optimizers like + +prefetching we'll get to. + +And other issues +[UNINTELLIGIBLE] + +this last one, but to deal +with cache axises. + +So if you have more than one +axis-- so here what I have is + +too nice arrays. + +[UNINTELLIGIBLE] is 2 to the +power size array 2 to the 19 + +power arrays. + +OK, so now what happens when +I put this in the cache? + +Look what happens in here. + +So what happens is this array +get mapped in this one. + +This array get maps this +nicely in here. + +So what happens is this line +can only be in this cache + +line, and this line also +only can be in + +this line of the cache. + +Do you see what's +going on, now? + +So if you do this one, basically +every time you + +access something-- + +See, assume I'm accessing this +data item, so I'm doing A, B. + +I access A, I get this line. + +I access B, what happens? + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: So this +[UNINTELLIGIBLE] is gone. + +It is gone. + +Now, I am accessing the +next one in that + +cache line we made. + +AUDIENCE: How do you know +what cache line-- or how + +[INAUDIBLE] + +cache? + +[INAUDIBLE] + +PROFESSOR: Normally, in language +like C, if people two + +arrays next to each other, they +should be mapped next to + +each other in memory. + +And if you want to be more +adventurous, you can go to the + +assembly and then see what +their locations is. + +So if you put A, A next to each +other, you normally kind + +of get it next to each other. + +So what this one is this +is pretty bad. + +I should have gotten at least +some spatial locality. + +I'm getting nothing. + +Do you see what's +going on here? + +Do you know what's +going on here? + +Know why I'm not getting +any spatial locality? + +Because I am bouncing. + +When I access this one, this one +is gone even though I have + +more data in the same cache +line, so I'm kind of bouncing + +two cache lines because +of that. + +What's a good solution +for this? + +Back there. + +AUDIENCE: [INAUDIBLE] + +A and B could be mapped to +the same cache line. + +PROFESSOR: The thing A is +a nice 2 to the power. + +A size is a multiple +of the cache size. + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: The size of A is a +multiple of the cache size. + +So what happens is if you have +memory in here, you map + +something like A, C here. + +If this is a multiple of cache +line, so assume this is 32K + +times some number, and you map +B here, and then this is + +normally what happens in C. +You put all adjacent map + +allocations next to each +other in memory. + +Do you got A here, and +you start having B in + +here, next to it. + +OK, so what happens is now if +A starts to assume address, + +we'll say 100, this is 100 plus +32K times N, basically. + +And you do this mod 32K, this +mod 32K, this same number. + +It maps into the same line. + +OK, so I kind of gave +you the problem. + +What can be the solution? + +AUDIENCE: [INAUDIBLE] + +allocate one line. + +PROFESSOR: Yes, it's +called padding. + +OK, so I have no locality in +here, let me go to the next + +slide, what kind of misses? + +I have cold and conflict. + +What I can do is just +basically add a + +little bit of padding. + +I did 16 here. + +Normally, you do a prime number +so it will not clash + +with anything. + +Add a little bit of padding at +the end of array, and that + +means the next array +will not be + +conflicted most of the time. + +So a lot of times when you +declare things next to each + +other, it's always good +to add a little bit of + +a padding in between. + +Normally, a smaller prime number +would be a good thing + +to add a padding. + +Now, I start getting back my +nice locality because the two + +things are mapping the +two cache lines. + +What type of locality +do I get here? + +Anybody want to take any +guess what type of + +locality I have here? + +AUDIENCE: Question, sorry. + +[INAUDIBLE] + +you actually added +just an extra 16. + +PROFESSOR: Yes. + +AUDIENCE: Why would that just +make the A and B [INAUDIBLE]? + +PROFESSOR: Because what happens +is normally it doesn't + +make A and B into leaving the +cache, but it makes A[0] + +not exactly matching to B[0]. + +A[0] + +will interleave with something +like B[16] + +or something. + +This thing might map into +the same place. + +AUDIENCE: I mean, but +I [INAUDIBLE]. + +PROFESSOR: Yes, normally +in a computation, + +people do that, A[i] + +equals B[i] + +plus something. + +AUDIENCE: Oh, OK, +so [INAUDIBLE]. + +Like I understand what you're +saying, but I don't understand + +how that [INAUDIBLE] + +because they're both accessing +[i] at the same time. + +Why would they [INAUDIBLE]? + +PROFESSOR: So here's +the problem. + +Assume I have [UNINTELLIGIBLE] + +32K. + +I'm assuming [UNINTELLIGIBLE]. + +OK, so first one is, we'll say, +you start with 100, 100 + +plus [i], and the other one +is 100 plus 32K plus [i]. + +OK, then you take a mod +32K, and this end up + +being 100 plus [i] + +with another 100 plus [i]. + +So this is basically +[UNINTELLIGIBLE]. + +You still have one or one +element in the cache it's all + +going to map into. + +You see that? + +But now, if I add 16 more to +this one, then this map into + +116 plus [i]. + +AUDIENCE: I don't see that +reflected in the code. + +You just [INAUDIBLE], so +how is B different + +from A in your code? + +PROFESSOR: Because +[UNINTELLIGIBLE] my S. I added + +16 to S, so my A is a little +bit bigger, now. + +AUDIENCE: But isn't B +also [INAUDIBLE]? + +PROFESSOR: Yeah, B's +also bigger here. + +I don't care. + +B goes down here. + +B, I add a little bit more to +the B. It doesn't matter. + +I padded B, too. + +So what that means +is the first A[i] + +and B[i] are not in the +same cache line. + +AUDIENCE: How do we allocate +A and B right + +next to each other? + +PROFESSOR: So normally in C, if +you declare something like + +int A [100], int B [100], more +or less, they will be + +allocated next to each other. + +If you look at the assembly +listing, it'll say code + +allocated next to each +other in memory. + +Even in the stack, if you do +that, if you allocate things, + +compiler has no incentive to +go and move things around. + +AUDIENCE: This is only for +global and [INAUDIBLE]? + +PROFESSOR: Global variable, +local variables. + +AUDIENCE: Does any of it still +apply if you use malloc? + +PROFESSOR: The thing +about malloc is-- + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: It might do something +[UNINTELLIGIBLE], + +but on the other hand, if it is +fitting on the same page, + +it might also do something +like that, too. + +So it depends on +how we do that. + +At the beginning, if you keep +mallocing things, it might be + +[UNINTELLIGIBLE]. + +They might be a little bit off +because malloc put some + +metadata with each status. + +If you ask for [UNINTELLIGIBLE], +you're not + +getting exactly 100. + +You're getting a little +bit of a bigger size. + +But you might have some +configuring to do, but after + +some time, when you have done a +lot of [UNINTELLIGIBLE], we + +have no idea where +it's going to go. + +It's random. + +Anymore questions? + +OK, good, that is +a good question. + +So what kind of locality +do I have here? + +[UNINTELLIGIBLE] + +two lines, I am accessing each, +and I got 16 times 15 + +out of 16 hits. + +What's that? + +AUDIENCE: Spatial? + +PROFESSOR: Spatial locality. + +And of course, if you have +spatial locality, you get cold + +misses, basically. + +And I think [UNINTELLIGIBLE], +you get what + +other type of misses? + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: [UNINTELLIGIBLE] +conflict here. + +Basically, capacity. + +Capacity miss, exactly. + +So in order to avoid this, what +we have done is we make + +cache-- instead of mapping into +one place before, and + +what we said was we had +this memory, and + +assume we have 32 sets. + +And if you have a cache like +this, we make this entire map + +into this one, and this +map into this one. + +What people have done is instead +of doing that, what + +you can make is make the cache, +instead of one big + +block, two small blocks. + +So what that means is this +can happen to this one. + +My drawings are not +that great, but I + +hope you get the picture. + +This map into this one, so +what that means is each + +reference here, so maps +here, and these + +two basically conflicts. + +But now with that +[UNINTELLIGIBLE] + +too, I can put this +one here or here. + +I have two places to put the +value, basically, and that + +[UNINTELLIGIBLE]. + +OK, so that means if I access +something conflicting, + +[UNINTELLIGIBLE], you cannot +just two things. + +Still, there are places in +the cache for them to go. + +And one way to do people is +fully associative cache. + +It can go anywhere, but that's +very hard to do in hardware, + +but you can do some small +number of ways. + +So in here, if you do two basic +associative cache, in + +the first axis in here, even +though these are conflicted, + +on can go to one +[UNINTELLIGIBLE] set, another + +one can go to the other set. + +OK, so two associative cache +[UNINTELLIGIBLE]. + +So total access time, again, I +have nice locality in here, + +spatial locality, and I have +both cold and, I guess, + +capacity misses. + +But if you have two associative +cache, what's the + +next problem? + +How about if you have three +different things? + +So we have two different +things like that. + +OK, now that I only have two +associated [UNINTELLIGIBLE], + +it doesn't work because, in +a [UNINTELLIGIBLE], I will + +replace the last thing, and you +might still end up with + +nothing in here because you are +replacing nothing, and the + +next thing replaced +the other thing. + +And basically after you +gave B, C, then you go + +to A. A Is not there. + +When you go to B, B is not +there, C is not there. + +You kind of go back to the same +problem in here, and then + +basically have to access +everything again. + +There is some spatial locality +but cache can't use it. + +Basically, you have +conflict misses. + +OK, so you see that? + +So associative is good because +normally people assume you + +don't need that much + +associativity, but it's limited. + +So if you have too many things, +you might run into + +this problem again. + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: You mean capacity? + +AUDIENCE: Yeah, [INAUDIBLE] +capacity. + +PROFESSOR: Less. + +AUDIENCE: [INAUDIBLE] + +elements in a cache before you +pick [INAUDIBLE] because it + +looks as though the matrix +is is using half + +the cache by itself. + +PROFESSOR: Because it's +associated, you mean? + +You have multiple there? + +I mean, the thing is since it's +associated, no, because + +you have enough room. + +I mean, if you're going +[UNINTELLIGIBLE] + +everything, you have two +places to put the + +name because it maps. + +That's a good question. + +So what happens is now, assume +this many things fit into the + +cache before. + +Now, cache has two banks, and +in each bank, only this many + +things fit in, but the +next thing can go + +to the other bank. + +So if you go through +[UNINTELLIGIBLE], you have the + +same behavior even if you +have associativity. + +OK, you can go and-- + +because if the cache is the same +size, the size is what + +matters for if you are going +through [UNINTELLIGIBLE] axis. + +AUDIENCE: So far, [INAUDIBLE] +machines that we're working + +on, do they have a fixed +kind of cache, or + +can we decide like-- + +PROFESSOR: The fixed +kind of cache. + +It's built into the hardware. + +I will show the table +to say what type of + +associativity is in there. + +AUDIENCE: Is there not a +way to say [INAUDIBLE] + +three-way associative? + +Can you have something on top +of it so that it looks like + +it's two-way associative +or something? + +PROFESSOR: I mean, you can do +things like that in software, + +but they're very expensive. + +I mean, think about cache is +trying to fool the cache in + +that direction cannot be that +easy because they are like + +really hard-baked into hardware. +that's a good + +question, but there are things +you can do, not exactly + +modeling something, but kind of +putting offsets and stuff + +like that so it doesn't get into +these kind of conflicts. + +So yeah, I will answer +this thing. + +Why don't you have more? + +Because if you go back to +your [UNINTELLIGIBLE] + +lectures. + +Perhaps it might have +explanation in it's hardware + +why it's much harder to build. + +And if you have the +linked lists now-- + +so assume I have linked lists we +are going through in here. + +And what's my [UNINTELLIGIBLE]? + +Basically, depending on +allocation and using some + +things, so best case is +everything is in cache, so I + +have a small list. + +And I go through again and +again, round and around my + +list, everything's in cache +and [UNINTELLIGIBLE] + +S. That's really great. + +Next best is everything +is adjacent. + +OK, everything might not be in +the cache, but everything at + +least in adjacent memory. + +So basically, first time I +allocate my malloc did a nice + +thing for me, and at that time, +I basically get a nice + +basic spatial locality since +my size is 16 in here. + +So I get this much. + +And the worst case is random. + +Malloc puts it all +over the place. + +Question? + +AUDIENCE: [INAUDIBLE] + +cache, does the thing behind it +[UNINTELLIGIBLE] in front + +of it [UNINTELLIGIBLE] +also going to? + +Do those both have a +spatial locality? + +PROFESSOR: What happens is +normally, we assume 64 element + +cache, so it's at that boundary, +so basically 2 to + +the 8 boundaries is +what happens. + +So what happens is cache line +begins at 0 address, 64 + +address here. + +So if you get 63, that means +this value is not in the + +cache, so you get +this cache line. + +So the cache line +doesn't shift. + +It's fixed chunks in here, so +that if you get address 0, you + +get this one, and all +these things. + +If you get something in the +middle, you'll get the left + +and right [UNINTELLIGIBLE], but +if you get here, you only + +get the right. + +So this basically 0 and 64, +they are boundaries + +[INAUDIBLE]. + +If you like 65, that's it. + +But that said, if you're +accessing [UNINTELLIGIBLE], + +that's this thing called +prefetcher that say you are + +going through linear pattern, +and you might need that next, + +and it'll bring this +up for you. + +And what you find, I'll show +later, that in fact, the + +machine you're using has a +really powerful prefetcher, so + +it can hide a lot +of these things. + +So we'll get to that. + +So this is my total access +time in here. + +Random case. + +Random case is basically, every +time I access something, + +it's not in the cache. + +And then if you have a bigger +struct in here-- + +but assume I have this big +struct in here, but I am only + +accessing one element of +this struct in here. + +I do a lot. + +I created this large struct, +and I am [UNINTELLIGIBLE] + +things in the struct, +and I just basically + +looking at my data. + +Only one element. + +What's the problem here? + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: Exactly, so I bring +the entire cache line, but I'm + +only using a little bit of it. + +Because I bring all these things +into the cache, it + +comes with axis and that, +but I'm only using data. + +So basically, what happens is, +if everything in the cache, I + +have access time S. +That's great. + +That's not a problem, +[UNINTELLIGIBLE] + +streaming. + +Even though I'm getting spatial +locality, I only get + +half of it because even though +I'm bringing the cache line, + +only two have datas because +this is 32 bytes long. + +It's in my cache. + +Even though I am bringing all +this data, I only two of them + +in the cache because rest of +this other data is kind of + +hanging in there with me, +and so I don't get that. + +And random, of course, +you have no locality. + +So how can I basically +make this better? + +How can I make this better? + +OK, I just showed +it very fast. + +OK. + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: So instead, if I +ask you, I have this large + +data structure, but most of +time, I'm only accessing a + +small part of it, this is kind +of a little bit of a hack. + +I mean, this is kind of going +against, I guess 6005 kind of + +building, but this +actually works. + +What you can do is, you can go +back and instead of doing + +structs, what you can do +is you can do arrays + +of each data item. + +And now what happens is that I +am basically bringing these, + +and then the data I am accessing +is basically right + +now next to each other. + +So you might have this very +large data structure + +representing something you +have a lot of, then. + +But most of the time, you're +only using few of them, so you + +don't have to be structs +of arrays. + +You might have couple of +different data structures. + +One is the one that you access +regularly hopefully you get + +them next to each other. + +And the nice thing about arrays +is it guarantees things + +are next to each other. + +Of course, was managing +it is harder. + +AUDIENCE: [UNINTELLIGIBLE] + +PROFESSOR: You can do both. + +So that means instead of doing +the structs, you use arrays of + +each field. + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: Instead of. + +So instead of doing this one, +you just do this one. + +AUDIENCE: [INAUDIBLE] + +instead of being able +to pass stuff over. + +Now you have to kind of be able +to know [UNINTELLIGIBLE], + +so what that is where because +you cannot just pass the + +struct [UNINTELLIGIBLE]. + +PROFESSOR: No, you can't +pass the struct. + +You basically have to pad the +index in here for this + +structure, basically. + +So you have to know something +in there. + +So this is a lot messier, but +it can actually give you a + +performance if you do this type +of access, so it's not + +something you want everywhere. + +That's why you still want to +use structures and nice + +classes and stuff. + +But this, if you're doing very +large data, but most of the + +you're accessing only small +amount, this kind of + +representation can help. + +So I want to get a little bit +into matrix multiplying. + +So what we're looking at is this +four by four matrix, and + +you can represent it using +this representation. + +But to make it clear, what I'm +going to do is I'm just going + +to allocate this entire thing +as a single array, and I'm + +going to do that +[UNINTELLIGIBLE] calculation + +myself because if you go a +little bit down, you realize + +this is allocated in a little +bit of a weird way. + +And so this is what we call +row-major because all rows are + +next to each other, and you +can access allocated + +column-major. + +Basically that means now A001, +instead of that, 1, 0 is next + +to 0, 0, 1, 0, 2, 0. + +And then basically saying same +thing, [UNINTELLIGIBLE] + +instead of saying 4i plus +j, it's just 4j plus i. + +You can do both. + +So this is my nice matrix +multiply function, because the + +reason I did it this way, it's +just very clear how many axis + +I'm going to use. + +So if you look at C, let's look +at only the inner loop. + +Most of the mapping matters +in the inner loop. + +I go for k in 0 to size. + +Only first axis on C is going to +miss because it's going up + +[UNINTELLIGIBLE] + +same K, da-da-da-da-da, so +C is very nice in here. + +Only get one miss in here. + +You have a question? + +OK. + +A has a streaming pattern +because every time I update K, + +I go to the next element, +next element, next + +element, next element. + +[INAUDIBLE]. + +What type of a pattern +do I have in B? + +AUDIENCE: Looks like +[INAUDIBLE]. + +PROFESSOR: Yeah, exactly. + +I have jumping on memory. + +I'm jumping one to another. + +So if you look at that, I am +going through A like that, and + +B, and going through C element +at a time, basically. + +So if you look at doing this +in order to calculate one + +element of A, [INAUDIBLE] +calculating these, what you + +have to do is I am getting +B and C this way. + +I'm going through row here +and column, and this row + +[UNINTELLIGIBLE] + +fit into the cache line through +that because this is + +the memory. + +But C is just jumping all over +the memory, and I have no + +locality in here. + +So what can we do here? + +What's the simplest +thing in here? + +How do we get some locality +into the C? + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: So yeah, you're +coming, you're getting it. + +That's the next thing that's +most important. + +That's the more advanced +thing you can do. + +We'll get there. + +What was a simple thing +you can do for C? + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: [UNINTELLIGIBLE] + +So here's the [UNINTELLIGIBLE] + +execution time, original, and +voila, when you transpose + +that, you can actually get a +huge benefit in here because, + +now, I get spatial locality +in both sides in here. + +And so now when you're +transposed, I am going + +through like this. + +So now what I did was I am +giving this CPI, and what + +happens is when you transpose, +I have a 5x + +improvement in sync CPI. + +That means instructions actually +not waiting, not + +doing nothing. + +I have a pretty good reduce +of cache misread. + +because, now, I'm +actually going + +through cache very nicely. + +So the next thing we can +do is, what she just + +pointed out, blocking. + +So instead of matrix multiply, +just multiplying this matrix + +at a time, you can multiply +submatrices and calculate + +small submatrices. + +And if you do that, the +submatrix can nicely fit in + +the memory, so let +me show you that. + +This is the blocking code. + +Let me show you what +that means. + +So what we are doing is you are +multiplying this matrix by + +this matrix in there and +getting this matrix. + +So what that means is, normally, +what you do is, to + +get one element, you have to +multiply a row and a column. + +Normally, we are calculating +a row of A at a time. + +In order to get a row of A, +I had to get a row of B + +[UNINTELLIGIBLE] + +entire C has to participate into +calculate A. So by the + +time I have calculated 1024 +elements, I have gone through + +this many axises to new elements +basically because I + +am getting B again and again, +but I had to go through the + +entire C in here. + +So if this much data is bigger +than the cache, I have no + +locality in here. + +But if, instead of calculating +a row, if I calculate a 32 by + +32 block, which is again 1024 +elements I am calculating. + +If I do that, I need a block +here and a block here, and I + +only type this much data. + +OK, I'm getting the same amount +of output, but because + +of reuse, I touch a lot +less inputting here. + +And just by doing this +transformation, I can really + +reduce the amount of data. + +Basically, I can create a +smaller working set, go + +through that much more, and +reduce the amount of cache + +misses you get. + +So by doing that, I basically go +out another 3x improvement + +in my CPI, really brought down +my L1 cache misses, and + +basically eliminated +L2 cache misses. + +OK, so I got a really good +speed up in here. + +So you can block multiple +levels, L1, L2, L3, because + +every time you figure out the +workings and size, you block + +so the data in that will be +safe in the cache in here. + +And this is kind of nasty +to do by hand. + +We'll see. + +So the other interesting thing +is call stack locality. + +So if you do something like fib +in here, traditional fib, + +if you do fib(4), you calculate +a fib(4), fib(3), + +fib(2), you kind of build +a stack, go up + +back again in here. + +So if you keep doing that, +the nice thing is you're + +going up, but its-- + +Hopefully, one of these days, +I am going to hit the wrong + +button, and-- + +What kind of locality do we have +if we are accessing data + +like this in my call stack? + +What kind of locality +do we have? + +I mean, I access here, fib(4), +and I get back to fib(4) here. + +So within each frame, I am +accessing data next to each + +other, so I can have a little +bit of a spatial locality + +because, each frame, all the +data is next to each other. + +But across frames, normally, +I will have some temporal + +because I will get back to +that data some time. + +OK? + +OK, before I summarize, +this one. + +If you are reading a lot of +data, processing through stage + +one, [UNINTELLIGIBLE] + +and producing [UNINTELLIGIBLE], +that means + +you're reading a huge amount +of data through stage one, + +save, save data again, do stage +two, you have really bad + +cache locality. + +One thing you can do is read a +small chunk, do all the stages + +on that small chunk, save it, +and go to another chunk. + +So instead of doing the entire +data, doing something + +[UNINTELLIGIBLE] + +producing, you can do this +chunk-ifying, and by doing + +that, you can get a +lot of locality. + +So once you bring in data, you +like to do as many things as + +possible to that data before +it gets out of the cache. + +That's the entire thing about +locality, and you can + +restructure code through that. + +So if you look at that, what +we have done today, we have + +looked at things like +associativity, cache lines, + +cache sets in here, and how to +address and map to a cache, we + +kind of did this thing, and we +look at [UNINTELLIGIBLE] + +streamings versus InCache +versus no + +locality type patterns. + +And then when you look at data +structure transformation, we + +look at how to basically replace +structured arrays and + +split data structures to make +sure that you get a lot of + +nice locality if you access a +certain amount of data, and + +pack data to get smaller cache +footprints kind of things. + +And we also look at computer +transformations, things like + +transpose copying, compute copy, +outtype things you can + +do, so you can actually get nice +locality, so you can do + +both data and compute +transformations. + +And [UNINTELLIGIBLE] + +axises and [? re-cast ?] + +calculation stages, so this +is kind of summary. + +Next thing I want go is +look at what machines + +you guys are using. + +So this is the machines +we used last year. + +These are quad cores, and it +had L1 cache, so these + +[UNINTELLIGIBLE]. + +So this has 32 kilobyte +L1 cache, data cache + +[UNINTELLIGIBLE] + +two caches in here for data and +instructions, each core, + +and then the cache line size +is normally 64 bytes + +[UNINTELLIGIBLE]. + +And here, latency +[UNINTELLIGIBLE], you get + +three cycles. + +If not, you get 14 cycles to +go to to L2 in here if data + +doesn't meet there. + +And associated with this +[UNINTELLIGIBLE PHRASE]. + +So that was what we +did last year. + +This year, we have a bigger +machine that has multiple + +levels of caches. + +So each core has L1 instruction +and data cache. + +It's kind of the same, 32 +kilobyte cache, four + +nanosecond latency in here. + +Eight, three and four +[UNINTELLIGIBLE], they kind of + +reduced that, but they added a +256-kilobyte L2 cache in here, + +and then a pretty large humongo + +12-megabyte L3 cache in here. + +The interesting thing is here, +this pretty fast access to + +these ones. + +If you miss in here, this is +about 2 and 1/2 times cost + +from going from here to here. + +From here to [UNINTELLIGIBLE], +about a five times cost, so + +here to here is a +five times cost. + +The interesting thing that +actually surprises a lot us + +was here to here, it's cost +is not that different. + +[UNINTELLIGIBLE PHRASE] + +So actually memory, even though +it's sitting out in + +there, they have managed to get +it pretty cheap access. + +Normally, my intuition say this +should be much higher + +because you're going off-chip, +so this is the structure here. + +It's a lot more complicated. + +So here's something I +produced last year. + +So what I did was I +ran this program. + +And in these machines, there's a +way to turn off the prefetch + +of the previous +[UNINTELLIGIBLE]. + +So when you've turned on the +prefetch and then you run, + +what you are doing is I am +accessing data with a working + +set, small working set, little +bit bigger working set. + +So this is basically when you +consider working set size. + +So you get a graph like this. + +I am hitting my L1 cache, and +if it is more than that, I + +[UNINTELLIGIBLE] + +L1 cache, I go to my L2 cache. + +And if L2 misses, I have +to go to main memory. + +Very traditional kind +of a graph in here. + +Another a little bit of an +interesting thing, which is + +instead of accessing +next item, I kind + +of skipped in here. + +So this trying to force how +to get conflict misses. + +And so if you line up things +like this exactly, what + +happens is you get these +conflict misses, and you get + +this number. + +So I have interesting +story to tell. + +When I was a graduate student, +we were running this bunch of + +benchmarks, and normally when +you run a benchmark, you try + +it for an equal + +[UNINTELLIGIBLE], stuff like that. + +And we got this graph +like this. + +I mean, we expect a graph +going like this. + +OK, that how a benchmark +[UNINTELLIGIBLE]. + +Then at one point, by accident, +instead of typing an + +equal 64-something, I typed an +equal 63, and suddenly, I got + +a performance like this. + +Wait a minute, what's +going on? + +So in here, what I got +was not a line. + +I got 16, 32, 64, 128, +nice graph like that. + +And then I just did 63, +like down to here. + +I'm like, geeze, that +can't be right. + +And then I start looking +at 62, which is here. + +61 is here. + +So I realize if I enumerate +all those things, I got a + +graph like this, basically. + +Kind of something like this. + +And the thing is, if I had never +tried the 63, I would + +have basically thought my +performance was like + +this, so far worse. + +Never realized because it was +all having conflicts in memory + +because I'm [UNINTELLIGIBLE] + +2 to the power numbers. + +So this is what happens if you +just look at 2 to the power + +numbers, you'll think, yeah, +this is the performance you're + +getting, without realizing +that, in fact, you + +can get this far. + +So this is good. + +So I ran it on the +new machine. + +The problem with our new machine +is there's no way to + +turn off prefetching. + +OK, so this is what +you're getting. + +Everything, because I am +accessing this nice linear, + +looks same. + +This is exactly what +you want to happen. + +What it's doing is, minute you +go to access, it realizes you + +accessing linearly. + +It start fetching, fetching, +fetching data in front you, + +it's going to catch up. + +It's not feeding you data, so +you're not going to have any + +cache missed because you're +going through this nice, + +linear pattern, and you just +basic end up with this + +beautiful graph, which gives the +feeling your working set + +could be, now, gigabytes long. + +At this point, I am fitting into +the entire L3 cache, and + +still look like this works +beautiful because this is what + +you want for it to figure out. + +So now I'm like, geeze, +this is great. + +This means my cache works, it's +very nice, but I want to + +show you guys what's going +on, so that doesn't help. + +So I came up with +this program. + +So this program, what I did was +I created a working set, + +but I'm accessing randomly +within that working set. + +I calculated this address. + +This is my poor man's random +number generator, so basically + +I'm adding number in here and +multiplying this, and then the + +masking these to get the +right [UNINTELLIGIBLE] + +so I get within that +set in here. + +And then I just access +data, so I'm getting + +[UNINTELLIGIBLE]. + +So I get a number like this, +and this jump up here, and + +then I had this kind +of behavior. + +This is a lot more +complicated. + +I need to figure out what the +hell is going on in here, so I + +said, OK, let's now look at +performance counters. + +I look at L1 cache miss. + +OK, up to 32K, I have +no cache misses. + +Boom, cache misses jump up. + +Perfect. + +And I have this little bit of a +kink in here, this beautiful + +describes because I have 32K +L1 cache, and until then, I + +have no things, and then when +the cache start missing, I'm + +jumping up. + +Perfect. + +I got that description here. + +Then I look at my +L2 cache misses. + +This is, I think, the L2 cache +in this machine might have a + +little bit more complex +[UNINTELLIGIBLE] + +telling us because this +is not going like + +here had jumping up. + +That's a 256K [UNINTELLIGIBLE] + +get. + +Is this 256? + +Yeah. + +[INAUDIBLE] + +250 is [UNINTELLIGIBLE] + +these things. + +OK, so we have 32 256 2L +megabytes in here. + +Even if you have 256 in here-- + +AUDIENCE: [INAUDIBLE] + +PROFESSOR: Hm? + +AUDIENCE: Should it +be 256 or 32-- + +PROFESSOR: [UNINTELLIGIBLE] + +because everything's backed +up, it's hierarchy + +[UNINTELLIGIBLE], so it's not +added to, it's not next to + +each other, because at this +point, L1 is now useless. + +It'll run everything is just +going to L2, so L2 is the one + +who was serving it. + +Come on. + +So what happens in here, this +normally should start jumping + +here, 256, but it start jumping +earlier, so there + +might be some other interesting + +thing going on here. + +It might be interesting +to investigate. + +So this is OK, so still +I am pretty close. + +I realized this jump is +basically because of L2 + +happen, this jump in here. + +L2 start missing. + +Then I look at L3. + +It's here. + +What's happening here? + +So this was a big mystery the +two of us were trying to debug + +what one hour ago. + +Not one hour. + +Class is going. + +Like two hours ago. + +We was trying to figure out, +OK, wait a minute, this + +doesn't make sense. + +My performance is here. + +L3 should be just basically a +nice flattening out here, and + +just jumping. + +It's not doing that, and we are +like what's going on here. + +So then we were scratching our +heads, and we start looking. + +I say, ha, there were other +things going on. + +We looked at this thing +called TLB. + +Let me tell you what TLB is. + +What we realize is at this +point, we are [? seeing ?] + +TLB misses. + +How many people know +what a TLB is? + +OK, good, so let me spend the +last couple of minutes + +explaining what a TLB this, +and that kind of explain + +what's going on in this graph. + +So TLB means-- + +Normally, data is stored in +memory using real addresses. + +That means there's a memory +size in here, there's an + +address format, there's certain +[UNINTELLIGIBLE]. + +And then the program for +it use virtual memory. + +That means programs want to feel +like they have a lot more + +memory than actual, physical +memory available. + +So what happens is you have +virtual memory address, but + +somebody has to map virtual +memory to physical memory. + +So the way it work is there's +a thing called translation + +lookaside buffer, TLB, that says +if you give this virtual + +address, here's the right +physical address. + +So of course you can't do it for +each address by address. + +What you have is you have 4K +pages, so the address space is + +broken down into 4K pages. + +Each page will have an entry in +this TLB, saying if you get + +this virtual address, here's +the right physical address. + +So normally what happens is when +the operating system they + +created this large table, for +every place in memory, you use + +this table, and it loads +into memory. + +Then the hardware will fetch +and cache some of those + +entries in this TLB +cache in there. + +So normally what happens is in +here, it caches 52L entries. + +It can keep 52L entries +to 52L pages, + +saying here's the mapping. + +The problem with 52L pages is +in a 4K byte page size, 52L + +pages can only hold two +megabytes of data. + +If you're accessing more than +two megabytes of data, you + +have to go more than 52L pages, +and at that point, that + +mapping is not in the TLB, and +that means that you have to go + +do a mapping translation. + +The problem for this is +these 4K pages is a + +very ancient artifact. + +There's the new machines, you +can I ask for what we call + +large-pages or super, but you +can ask for 2-megabyte or + +4-megabyte pages. + +If you ask for super-pages, then +of course, 52L entry's + +good enough. + +It can hold enough things not +to have TLB miss, at least + +while you're in the cache. + +But since Linux, without doing +anything, only asks for 4K + +pages, before you run out of +your L3 cache, you run out of + +the TLB table. + +And it has to start fetching +and [UNINTELLIGIBLE] + +data table, that means you had +to actually fetch the table + +entries, and so you have +to do more fetchings. + +So that is why this is even +running higher, because it's + +trying to fetch this TLB entry +and stuff like that. + +Question? + +AUDIENCE: Is there a way to then +actually fiddle with the + +TLB so that you have to fit +your pages rather than-- + +PROFESSOR: So in allocation, you +can ask for super-pages or + +large-pages. + +But in Linux, normally just ask +for 4K pages, so that the + +operating systems haven't +kind of caught up + +to the current hardware. + +And this is was built +[UNINTELLIGIBLE] + +doesn't make sense TLB +to run out before + +you run out the cache. + +I mean, that's kind of +mismatch in here. + +But it's built assuming you'll +get large-pages, but if you + +don't, you're going to run +out of the TLB in there. + +So this is why sometimes +performance engineering is + +interesting, exciting, and +frustrating, because you + +assume you know where the +hell this is going. + +You assume this is going to go +here and that, and suddenly, + +this miss shows up, and so we +have to scratch our heads. + +And luckily, we found what's +going on, but we could have + +spent hours or days trying to +figure out what's going on + +here because this is one +[UNINTELLIGIBLE] + +say OK, let's try TLB, +and it worked. + +That was really good, but I +have, many cases, spent days + +trying to figure out why +something is going on because + +performance is kind of +a [UNINTELLIGIBLE] + +of everything. + +There's no nice abstractions +and stuff like that. + +If you think abstraction wise, +somewhere outside the + +abstraction, that's +going to kill you. + +So that is why it can be +interesting, because you have + +to know everything. + +And the fun thing is, once you +understand performance, you + +basically understand end-to-end, +soup to nuts, + +what's going on. + +OK, with that encouraging +thought, let's see how you + +guys do in the next part +of project two. \ No newline at end of file diff --git a/lA8-N_ARHTw.txt b/lA8-N_ARHTw.txt new file mode 100644 index 0000000000000000000000000000000000000000..43c0814a91fa74b548f12c64dd212adc7db2a1d2 --- /dev/null +++ b/lA8-N_ARHTw.txt @@ -0,0 +1,883 @@ +align:start position:0% + +we have found in this solution with some + + align:start position:0% +we have found in this solution with some + + + align:start position:0% +we have found in this solution with some +energy like this that there's a decaying + + align:start position:0% +energy like this that there's a decaying + + + align:start position:0% +energy like this that there's a decaying +exponential over this side and the + + align:start position:0% +exponential over this side and the + + + align:start position:0% +exponential over this side and the +question is often asked well what + + align:start position:0% +question is often asked well what + + + align:start position:0% +question is often asked well what +happens if you try to measure the + + align:start position:0% +happens if you try to measure the + + + align:start position:0% +happens if you try to measure the +particle in the forbidden region must be + + align:start position:0% +particle in the forbidden region must be + + + align:start position:0% +particle in the forbidden region must be +a problem if you find the particle in + + align:start position:0% +a problem if you find the particle in + + + align:start position:0% +a problem if you find the particle in +the forbidden region it has energy that + + align:start position:0% +the forbidden region it has energy that + + + align:start position:0% +the forbidden region it has energy that +is less than V naught so you you have + + align:start position:0% +is less than V naught so you you have + + + align:start position:0% +is less than V naught so you you have +found a particle with negative kinetic + + align:start position:0% +found a particle with negative kinetic + + + align:start position:0% +found a particle with negative kinetic +energy how does it look how can it + + align:start position:0% +energy how does it look how can it + + + align:start position:0% +energy how does it look how can it +happen what's going on can you really + + align:start position:0% +happen what's going on can you really + + + align:start position:0% +happen what's going on can you really +find the particle in the forbidden + + align:start position:0% +find the particle in the forbidden + + + align:start position:0% +find the particle in the forbidden +region and then how does this negative + + align:start position:0% +region and then how does this negative + + + align:start position:0% +region and then how does this negative +kinetic energy look like and the answer + + align:start position:0% +kinetic energy look like and the answer + + + align:start position:0% +kinetic energy look like and the answer +is that it's kind of funny what happens + + align:start position:0% +is that it's kind of funny what happens + + + align:start position:0% +is that it's kind of funny what happens +here you can make two statements it + + align:start position:0% +here you can make two statements it + + + align:start position:0% +here you can make two statements it +would be contradictory contradictory + + align:start position:0% + + + + align:start position:0% + +theory if you could make could say the + + align:start position:0% +theory if you could make could say the + + + align:start position:0% +theory if you could make could say the +following things one that the particle + + align:start position:0% +following things one that the particle + + + align:start position:0% +following things one that the particle +is in the forbidden region forbidden + + align:start position:0% +is in the forbidden region forbidden + + + align:start position:0% +is in the forbidden region forbidden +region until that the particle has + + align:start position:0% +region until that the particle has + + + align:start position:0% +region until that the particle has +energy less than V naught because then + + align:start position:0% +energy less than V naught because then + + + align:start position:0% +energy less than V naught because then +it would mean negative kinetic energy so + + align:start position:0% +it would mean negative kinetic energy so + + + align:start position:0% +it would mean negative kinetic energy so +if you can say these two things it seems + + align:start position:0% +if you can say these two things it seems + + + align:start position:0% +if you can say these two things it seems +a contradictory so quantum mechanics + + align:start position:0% +a contradictory so quantum mechanics + + + align:start position:0% +a contradictory so quantum mechanics +evades this problem now this is not + + align:start position:0% +evades this problem now this is not + + + align:start position:0% +evades this problem now this is not +discussed as far I can see except in + + align:start position:0% +discussed as far I can see except in + + + align:start position:0% +discussed as far I can see except in +some lecture loads of Gordon beam and + + align:start position:0% +some lecture loads of Gordon beam and + + + align:start position:0% +some lecture loads of Gordon beam and +and because the argument is not a + + align:start position:0% +and because the argument is not a + + + align:start position:0% +and because the argument is not a +hundred percent precise but I think the + + align:start position:0% +hundred percent precise but I think the + + + align:start position:0% +hundred percent precise but I think the +spirit of the argument is clear so I + + align:start position:0% +spirit of the argument is clear so I + + + align:start position:0% +spirit of the argument is clear so I +want to share it with you so here is the + + align:start position:0% +want to share it with you so here is the + + + align:start position:0% +want to share it with you so here is the +catch + + align:start position:0% + + + + align:start position:0% + +this particle remember it's governed by + + align:start position:0% +this particle remember it's governed by + + + align:start position:0% +this particle remember it's governed by +e to the minus Kappa X in the forbidden + + align:start position:0% +e to the minus Kappa X in the forbidden + + + align:start position:0% +e to the minus Kappa X in the forbidden +region so the length scale here where + + align:start position:0% +region so the length scale here where + + + align:start position:0% +region so the length scale here where +you can find it the particle the length + + align:start position:0% +you can find it the particle the length + + + align:start position:0% +you can find it the particle the length +scale is this forbidden region stretches + + align:start position:0% +scale is this forbidden region stretches + + + align:start position:0% +scale is this forbidden region stretches +to about X of the order 1 over Kappa you + + align:start position:0% +to about X of the order 1 over Kappa you + + + align:start position:0% +to about X of the order 1 over Kappa you +know if you are going to find it in the + + align:start position:0% +know if you are going to find it in the + + + align:start position:0% +know if you are going to find it in the +region of a distance 1 over Kappa at N 1 + + align:start position:0% +region of a distance 1 over Kappa at N 1 + + + align:start position:0% +region of a distance 1 over Kappa at N 1 +over Kappa you're not going to find it + + align:start position:0% +over Kappa you're not going to find it + + + align:start position:0% +over Kappa you're not going to find it +exponential is too small but remember + + align:start position:0% +exponential is too small but remember + + + align:start position:0% +exponential is too small but remember +what was Kappa Kappa squared was 2m V + + align:start position:0% +what was Kappa Kappa squared was 2m V + + + align:start position:0% +what was Kappa Kappa squared was 2m V +naught minus e over H squared that's + + align:start position:0% +naught minus e over H squared that's + + + align:start position:0% +naught minus e over H squared that's +what it was now if you want to look to + + align:start position:0% +what it was now if you want to look to + + + align:start position:0% +what it was now if you want to look to +see and declare that you have this + + align:start position:0% +see and declare that you have this + + + align:start position:0% +see and declare that you have this +particle you would have to be able to + + align:start position:0% +particle you would have to be able to + + + align:start position:0% +particle you would have to be able to +measure position with some precision + + align:start position:0% +measure position with some precision + + + align:start position:0% +measure position with some precision +with a precision small a little smaller + + align:start position:0% +with a precision small a little smaller + + + align:start position:0% +with a precision small a little smaller +than this otherwise if you measure with + + align:start position:0% +than this otherwise if you measure with + + + align:start position:0% +than this otherwise if you measure with +precision ten times that well maybe to + + align:start position:0% +precision ten times that well maybe to + + + align:start position:0% +precision ten times that well maybe to +the left maybe it's somewhere else so + + align:start position:0% +the left maybe it's somewhere else so + + + align:start position:0% +the left maybe it's somewhere else so +you need to measure position with Delta + + align:start position:0% +you need to measure position with Delta + + + align:start position:0% +you need to measure position with Delta +X a little smaller than one over Kappa + + align:start position:0% +X a little smaller than one over Kappa + + + align:start position:0% +X a little smaller than one over Kappa +otherwise you cannot really tell it's + + align:start position:0% +otherwise you cannot really tell it's + + + align:start position:0% +otherwise you cannot really tell it's +inside the forbidden region but now the + + align:start position:0% +inside the forbidden region but now the + + + align:start position:0% +inside the forbidden region but now the +problem is that if you do a position + + align:start position:0% +problem is that if you do a position + + + align:start position:0% +problem is that if you do a position +measurement there's gonna and you + + align:start position:0% +measurement there's gonna and you + + + align:start position:0% +measurement there's gonna and you +localize the wave function there's a + + align:start position:0% +localize the wave function there's a + + + align:start position:0% +localize the wave function there's a +momentum uncertainty the particle that + + align:start position:0% +momentum uncertainty the particle that + + + align:start position:0% +momentum uncertainty the particle that +you're looking at as opposed to the + + align:start position:0% +you're looking at as opposed to the + + + align:start position:0% +you're looking at as opposed to the +particle to the left has no momentum + + align:start position:0% +particle to the left has no momentum + + + align:start position:0% +particle to the left has no momentum +it's it's a different kind of wave + + align:start position:0% +it's it's a different kind of wave + + + align:start position:0% +it's it's a different kind of wave +function there's no momentum really + + align:start position:0% +function there's no momentum really + + + align:start position:0% +function there's no momentum really +associated or well-defined momentum to + + align:start position:0% +associated or well-defined momentum to + + + align:start position:0% +associated or well-defined momentum to +it + + align:start position:0% +it + + + align:start position:0% +it +so because you make a position you + + align:start position:0% +so because you make a position you + + + align:start position:0% +so because you make a position you +localize in X whatever wave function you + + align:start position:0% +localize in X whatever wave function you + + + align:start position:0% +localize in X whatever wave function you +have you're going to have some + + align:start position:0% +have you're going to have some + + + align:start position:0% +have you're going to have some +uncertainty + + align:start position:0% +uncertainty + + + align:start position:0% +uncertainty +20 and some momentum that is going to be + + align:start position:0% +20 and some momentum that is going to be + + + align:start position:0% +20 and some momentum that is going to be +of kind of bigger than h-bar over Delta + + align:start position:0% +of kind of bigger than h-bar over Delta + + + align:start position:0% +of kind of bigger than h-bar over Delta +X so a momentum that is bigger than of + + align:start position:0% +X so a momentum that is bigger than of + + + align:start position:0% +X so a momentum that is bigger than of +or a little bigger than h-bar Kappa you + + align:start position:0% +or a little bigger than h-bar Kappa you + + + align:start position:0% +or a little bigger than h-bar Kappa you +know if Delta X is less than that the + + align:start position:0% +know if Delta X is less than that the + + + align:start position:0% +know if Delta X is less than that the +inequality goes in the same direction so + + align:start position:0% +inequality goes in the same direction so + + + align:start position:0% +inequality goes in the same direction so +there's going to be an uncertainty P and + + align:start position:0% +there's going to be an uncertainty P and + + + align:start position:0% +there's going to be an uncertainty P and +therefore this particle has now some + + align:start position:0% +therefore this particle has now some + + + align:start position:0% +therefore this particle has now some +kinetic energy due to this uncertain + + align:start position:0% +kinetic energy due to this uncertain + + + align:start position:0% +kinetic energy due to this uncertain +momentum so our uncertainty in the + + align:start position:0% +momentum so our uncertainty in the + + + align:start position:0% +momentum so our uncertainty in the +kinetic energy is how much is P squared + + align:start position:0% +kinetic energy is how much is P squared + + + align:start position:0% +kinetic energy is how much is P squared +over 2m where P is this uncertain + + align:start position:0% +over 2m where P is this uncertain + + + align:start position:0% +over 2m where P is this uncertain +momentum so this is equal to H bar Kappa + + align:start position:0% +momentum so this is equal to H bar Kappa + + + align:start position:0% +momentum so this is equal to H bar Kappa +squared over 2m which is equal to V + + align:start position:0% +squared over 2m which is equal to V + + + align:start position:0% +squared over 2m which is equal to V +naught minus e so actually if you think + + align:start position:0% +naught minus e so actually if you think + + + align:start position:0% +naught minus e so actually if you think +about it + + align:start position:0% +about it + + + align:start position:0% +about it +here is V naught this difference is V + + align:start position:0% +here is V naught this difference is V + + + align:start position:0% +here is V naught this difference is V +naught minus E and you are going to say + + align:start position:0% +naught minus E and you are going to say + + + align:start position:0% +naught minus E and you are going to say +oh I found the particle it has negative + + align:start position:0% +oh I found the particle it has negative + + + align:start position:0% +oh I found the particle it has negative +kinetic energy but not answer to the + + align:start position:0% +kinetic energy but not answer to the + + + align:start position:0% +kinetic energy but not answer to the +principles that you found it localized + + align:start position:0% +principles that you found it localized + + + align:start position:0% +principles that you found it localized +okay your kinetic energy I'm sorry now + + align:start position:0% +okay your kinetic energy I'm sorry now + + + align:start position:0% +okay your kinetic energy I'm sorry now +has an uncertainty how much V not minus + + align:start position:0% +has an uncertainty how much V not minus + + + align:start position:0% +has an uncertainty how much V not minus +E so whatever you wanted to prove it has + + align:start position:0% +E so whatever you wanted to prove it has + + + align:start position:0% +E so whatever you wanted to prove it has +been disproved you can't do it the total + + align:start position:0% +been disproved you can't do it the total + + + align:start position:0% +been disproved you can't do it the total +energy total energy is now e + + align:start position:0% +energy total energy is now e + + + align:start position:0% +energy total energy is now e +plus the uncertainty in the energy which + + align:start position:0% +plus the uncertainty in the energy which + + + align:start position:0% +plus the uncertainty in the energy which +is e plus V naught minus E and it's + + align:start position:0% +is e plus V naught minus E and it's + + + align:start position:0% +is e plus V naught minus E and it's +therefore greater than or equal to V + + align:start position:0% +therefore greater than or equal to V + + + align:start position:0% +therefore greater than or equal to V +naught and no no real contradiction so + + align:start position:0% +naught and no no real contradiction so + + + align:start position:0% +naught and no no real contradiction so +then certainly principle sort of + + align:start position:0% +then certainly principle sort of + + + align:start position:0% +then certainly principle sort of +conspires to prevent you from finding a + + align:start position:0% +conspires to prevent you from finding a + + + align:start position:0% +conspires to prevent you from finding a +particle with negative kinetic energy + + align:start position:0% +particle with negative kinetic energy + + + align:start position:0% +particle with negative kinetic energy +and if you do detect the particle in the + + align:start position:0% +and if you do detect the particle in the + + + align:start position:0% +and if you do detect the particle in the +furby + + align:start position:0% +furby + + + align:start position:0% +furby +originally will have energy total energy + + align:start position:0% +originally will have energy total energy + + + align:start position:0% +originally will have energy total energy +zero or total kinetic energy zero it + + align:start position:0% +zero or total kinetic energy zero it + + + align:start position:0% +zero or total kinetic energy zero it +will be a normal particle nothing + + align:start position:0% +will be a normal particle nothing + + + align:start position:0% +will be a normal particle nothing +strange about \ No newline at end of file diff --git a/lkrsGRNsoEU.txt b/lkrsGRNsoEU.txt new file mode 100644 index 0000000000000000000000000000000000000000..6a4a2b210fa7bdd75dae1d7a9930e95506dab7b1 --- /dev/null +++ b/lkrsGRNsoEU.txt @@ -0,0 +1,1675 @@ +align:start position:0% + +okay so solving successfully finished + + align:start position:0% +okay so solving successfully finished + + + align:start position:0% +okay so solving successfully finished +and we've got the results if you had any + + align:start position:0% +and we've got the results if you had any + + + align:start position:0% +and we've got the results if you had any +trouble solving this problem then you + + align:start position:0% +trouble solving this problem then you + + + align:start position:0% +trouble solving this problem then you +should go into options in the solver and + + align:start position:0% +should go into options in the solver and + + + align:start position:0% +should go into options in the solver and +select that you want to edit the length + + align:start position:0% +select that you want to edit the length + + + align:start position:0% +select that you want to edit the length +of solution time and increase it past + + align:start position:0% +of solution time and increase it past + + + align:start position:0% +of solution time and increase it past +100 seconds the LibreOffice solver is + + align:start position:0% +100 seconds the LibreOffice solver is + + + align:start position:0% +100 seconds the LibreOffice solver is +not incredibly powerful so it may need + + align:start position:0% +not incredibly powerful so it may need + + + align:start position:0% +not incredibly powerful so it may need +more time to find the solution we do + + align:start position:0% +more time to find the solution we do + + + align:start position:0% +more time to find the solution we do +recommend that if you have access to + + align:start position:0% +recommend that if you have access to + + + align:start position:0% +recommend that if you have access to +Excel that you use Excel instead for + + align:start position:0% +Excel that you use Excel instead for + + + align:start position:0% +Excel that you use Excel instead for +integer optimization problems because + + align:start position:0% +integer optimization problems because + + + align:start position:0% +integer optimization problems because +Excel is a little bit better with + + align:start position:0% +Excel is a little bit better with + + + align:start position:0% +Excel is a little bit better with +integer optimization however you + + align:start position:0% +integer optimization however you + + + align:start position:0% +integer optimization however you +probably got the solution just fine so + + align:start position:0% +probably got the solution just fine so + + + align:start position:0% +probably got the solution just fine so +you'll want to go ahead and click keep + + align:start position:0% +you'll want to go ahead and click keep + + + align:start position:0% +you'll want to go ahead and click keep +results okay so now we can take a look + + align:start position:0% +results okay so now we can take a look + + + align:start position:0% +results okay so now we can take a look +at our solution so we've got the + + align:start position:0% +at our solution so we've got the + + + align:start position:0% +at our solution so we've got the +objective of 4.46 this is not + + align:start position:0% +objective of 4.46 this is not + + + align:start position:0% +objective of 4.46 this is not +particularly interpretable until you + + align:start position:0% +particularly interpretable until you + + + align:start position:0% +particularly interpretable until you +remember that what our objective is is + + align:start position:0% +remember that what our objective is is + + + align:start position:0% +remember that what our objective is is +the total of all departments percent of + + align:start position:0% +the total of all departments percent of + + + align:start position:0% +the total of all departments percent of +target allocation hours reached so the + + align:start position:0% +target allocation hours reached so the + + + align:start position:0% +target allocation hours reached so the +best possible number that we could get + + align:start position:0% +best possible number that we could get + + + align:start position:0% +best possible number that we could get +here would be five if every department + + align:start position:0% +here would be five if every department + + + align:start position:0% +here would be five if every department +had 100 percent of their target + + align:start position:0% +had 100 percent of their target + + + align:start position:0% +had 100 percent of their target +allocation hours reached so we've got + + align:start position:0% +allocation hours reached so we've got + + + align:start position:0% +allocation hours reached so we've got +four point four six so let's go up and + + align:start position:0% +four point four six so let's go up and + + + align:start position:0% +four point four six so let's go up and +take a look at the solution so we're + + align:start position:0% +take a look at the solution so we're + + + align:start position:0% +take a look at the solution so we're +giving ophthalmology a total of four + + align:start position:0% +giving ophthalmology a total of four + + + align:start position:0% +giving ophthalmology a total of four +operating rooms per week which is 32 + + align:start position:0% +operating rooms per week which is 32 + + + align:start position:0% +operating rooms per week which is 32 +weekly hours or 81 percent of their + + align:start position:0% +weekly hours or 81 percent of their + + + align:start position:0% +weekly hours or 81 percent of their +target we're giving gynecology 14 which + + align:start position:0% +target we're giving gynecology 14 which + + + align:start position:0% +target we're giving gynecology 14 which +is 112 weekly hours 95 percent of their + + align:start position:0% +is 112 weekly hours 95 percent of their + + + align:start position:0% +is 112 weekly hours 95 percent of their +target we're giving oral surgery too and + + align:start position:0% +target we're giving oral surgery too and + + + align:start position:0% +target we're giving oral surgery too and +as we see the constraints restricted us + + align:start position:0% +as we see the constraints restricted us + + + align:start position:0% +as we see the constraints restricted us +so that we only gave oral surgery + + align:start position:0% +so that we only gave oral surgery + + + align:start position:0% +so that we only gave oral surgery +operating rooms on Tuesdays and + + align:start position:0% +operating rooms on Tuesdays and + + + align:start position:0% +operating rooms on Tuesdays and +Thursdays + + align:start position:0% +Thursdays + + + align:start position:0% +Thursdays +this is 80% of the target we gave + + align:start position:0% +this is 80% of the target we gave + + + align:start position:0% +this is 80% of the target we gave +general surgery three operating rooms + + align:start position:0% +general surgery three operating rooms + + + align:start position:0% +general surgery three operating rooms +and we gave hope sorry we gave + + align:start position:0% +and we gave hope sorry we gave + + + align:start position:0% +and we gave hope sorry we gave +Otolaryngology three operating rooms and + + align:start position:0% +Otolaryngology three operating rooms and + + + align:start position:0% +Otolaryngology three operating rooms and +general surgery 23 operating rooms + + align:start position:0% +general surgery 23 operating rooms + + + align:start position:0% +general surgery 23 operating rooms +getting 91 and 97 percent of their + + align:start position:0% +getting 91 and 97 percent of their + + + align:start position:0% +getting 91 and 97 percent of their +target allocation hours so suppose that + + align:start position:0% +target allocation hours so suppose that + + + align:start position:0% +target allocation hours so suppose that +you were the operating room manager who + + align:start position:0% +you were the operating room manager who + + + align:start position:0% +you were the operating room manager who +knows integer optimization in practice + + align:start position:0% +knows integer optimization in practice + + + align:start position:0% +knows integer optimization in practice +what would happen is that you would go + + align:start position:0% +what would happen is that you would go + + + align:start position:0% +what would happen is that you would go +off and you would design what we + + align:start position:0% +off and you would design what we + + + align:start position:0% +off and you would design what we +did here in the recitation you would + + align:start position:0% +did here in the recitation you would + + + align:start position:0% +did here in the recitation you would +have this optimization model for + + align:start position:0% +have this optimization model for + + + align:start position:0% +have this optimization model for +operating room scheduling in the + + align:start position:0% +operating room scheduling in the + + + align:start position:0% +operating room scheduling in the +hospital you'd solve it you'd find the + + align:start position:0% +hospital you'd solve it you'd find the + + + align:start position:0% +hospital you'd solve it you'd find the +optimal solution and you'd come back and + + align:start position:0% +optimal solution and you'd come back and + + + align:start position:0% +optimal solution and you'd come back and +present it to the surgical departments + + align:start position:0% +present it to the surgical departments + + + align:start position:0% +present it to the surgical departments +and they'll look at the schedule and all + + align:start position:0% +and they'll look at the schedule and all + + + align:start position:0% +and they'll look at the schedule and all +of a sudden they'll tell you it doesn't + + align:start position:0% +of a sudden they'll tell you it doesn't + + + align:start position:0% +of a sudden they'll tell you it doesn't +work for them and you'll say why not + + align:start position:0% +work for them and you'll say why not + + + align:start position:0% +work for them and you'll say why not +I incorporated everything that you asked + + align:start position:0% +I incorporated everything that you asked + + + align:start position:0% +I incorporated everything that you asked +for and it's true you did but oftentimes + + align:start position:0% +for and it's true you did but oftentimes + + + align:start position:0% +for and it's true you did but oftentimes +there are actually other constraints + + align:start position:0% +there are actually other constraints + + + align:start position:0% +there are actually other constraints +that they forgot to tell you about so + + align:start position:0% +that they forgot to tell you about so + + + align:start position:0% +that they forgot to tell you about so +what would you do in that case well + + align:start position:0% +what would you do in that case well + + + align:start position:0% +what would you do in that case well +you'd listen to their additional + + align:start position:0% +you'd listen to their additional + + + align:start position:0% +you'd listen to their additional +constraints and go back and add them to + + align:start position:0% +constraints and go back and add them to + + + align:start position:0% +constraints and go back and add them to +the model so that's exactly what we'll + + align:start position:0% +the model so that's exactly what we'll + + + align:start position:0% +the model so that's exactly what we'll +do here suppose the general surgery + + align:start position:0% +do here suppose the general surgery + + + align:start position:0% +do here suppose the general surgery +department took a look at the schedule + + align:start position:0% +department took a look at the schedule + + + align:start position:0% +department took a look at the schedule +and said oh great we have 23 operating + + align:start position:0% +and said oh great we have 23 operating + + + align:start position:0% +and said oh great we have 23 operating +rooms per week that's exactly 2 less + + align:start position:0% +rooms per week that's exactly 2 less + + + align:start position:0% +rooms per week that's exactly 2 less +than actually our maximum it's right in + + align:start position:0% +than actually our maximum it's right in + + + align:start position:0% +than actually our maximum it's right in +between our minimum or maximum and we're + + align:start position:0% +between our minimum or maximum and we're + + + align:start position:0% +between our minimum or maximum and we're +getting 97% of our weekly target we + + align:start position:0% +getting 97% of our weekly target we + + + align:start position:0% +getting 97% of our weekly target we +think that's wonderful + + align:start position:0% +think that's wonderful + + + align:start position:0% +think that's wonderful +however it's a little bit uneven you + + align:start position:0% +however it's a little bit uneven you + + + align:start position:0% +however it's a little bit uneven you +know six on Wednesday three on Thursday + + align:start position:0% +know six on Wednesday three on Thursday + + + align:start position:0% +know six on Wednesday three on Thursday +can we just have at least four per day + + align:start position:0% +can we just have at least four per day + + + align:start position:0% +can we just have at least four per day +okay well we can do that so let's go up + + align:start position:0% +okay well we can do that so let's go up + + + align:start position:0% +okay well we can do that so let's go up +to the minimum number of operating rooms + + align:start position:0% +to the minimum number of operating rooms + + + align:start position:0% +to the minimum number of operating rooms +per day and for general surgery let's + + align:start position:0% +per day and for general surgery let's + + + align:start position:0% +per day and for general surgery let's +change this from 0 to 4 this will help + + align:start position:0% +change this from 0 to 4 this will help + + + align:start position:0% +change this from 0 to 4 this will help +them balance throughout the week and + + align:start position:0% +them balance throughout the week and + + + align:start position:0% +them balance throughout the week and +potentially ophthalmology we'll look at + + align:start position:0% +potentially ophthalmology we'll look at + + + align:start position:0% +potentially ophthalmology we'll look at +their schedule and they'll think the + + align:start position:0% +their schedule and they'll think the + + + align:start position:0% +their schedule and they'll think the +same thing and they'll think well we + + align:start position:0% +same thing and they'll think well we + + + align:start position:0% +same thing and they'll think well we +actually would prefer to balance it + + align:start position:0% +actually would prefer to balance it + + + align:start position:0% +actually would prefer to balance it +throughout the week we want at most one + + align:start position:0% +throughout the week we want at most one + + + align:start position:0% +throughout the week we want at most one +operating room per day we don't want to + + align:start position:0% +operating room per day we don't want to + + + align:start position:0% +operating room per day we don't want to +have two on Monday let's put one of + + align:start position:0% +have two on Monday let's put one of + + + align:start position:0% +have two on Monday let's put one of +those on Thursday or Friday so that's ok + + align:start position:0% +those on Thursday or Friday so that's ok + + + align:start position:0% +those on Thursday or Friday so that's ok +we can do that too we just go to the + + align:start position:0% +we can do that too we just go to the + + + align:start position:0% +we can do that too we just go to the +maximum number of operating rooms per + + align:start position:0% +maximum number of operating rooms per + + + align:start position:0% +maximum number of operating rooms per +day and for ophthalmology we change it + + align:start position:0% +day and for ophthalmology we change it + + + align:start position:0% +day and for ophthalmology we change it +to 1 let's resolve the model and see + + align:start position:0% +to 1 let's resolve the model and see + + + align:start position:0% +to 1 let's resolve the model and see +what we get again we select the + + align:start position:0% +what we get again we select the + + + align:start position:0% +what we get again we select the +objective go to tools pull down the + + align:start position:0% +objective go to tools pull down the + + + align:start position:0% +objective go to tools pull down the +solver it should have everything already + + align:start position:0% +solver it should have everything already + + + align:start position:0% +solver it should have everything already +loaded up and we just get to hit solve + + align:start position:0% +loaded up and we just get to hit solve + + + align:start position:0% +loaded up and we just get to hit solve +all right so that was quick solving + + align:start position:0% +all right so that was quick solving + + + align:start position:0% +all right so that was quick solving +successfully finished and it looks like + + align:start position:0% +successfully finished and it looks like + + + align:start position:0% +successfully finished and it looks like +we actually have exactly the same + + align:start position:0% +we actually have exactly the same + + + align:start position:0% +we actually have exactly the same +results as we had before + + align:start position:0% +results as we had before + + + align:start position:0% +results as we had before +let's hit keep result and take a closer + + align:start position:0% +let's hit keep result and take a closer + + + align:start position:0% +let's hit keep result and take a closer +look at this so our objective functions + + align:start position:0% +look at this so our objective functions + + + align:start position:0% +look at this so our objective functions +stayed exactly the same but we were able + + align:start position:0% +stayed exactly the same but we were able + + + align:start position:0% +stayed exactly the same but we were able +to incorporate the new constraints the + + align:start position:0% +to incorporate the new constraints the + + + align:start position:0% +to incorporate the new constraints the +new requirement that the general surgery + + align:start position:0% +new requirement that the general surgery + + + align:start position:0% +new requirement that the general surgery +department have at least four operating + + align:start position:0% +department have at least four operating + + + align:start position:0% +department have at least four operating +rooms per day and that the ophthalmology + + align:start position:0% +rooms per day and that the ophthalmology + + + align:start position:0% +rooms per day and that the ophthalmology +department have at most one operating + + align:start position:0% +department have at most one operating + + + align:start position:0% +department have at most one operating +room per day this means that within the + + align:start position:0% +room per day this means that within the + + + align:start position:0% +room per day this means that within the +solution we had before there's actually + + align:start position:0% +solution we had before there's actually + + + align:start position:0% +solution we had before there's actually +a little bit of wiggle room we could + + align:start position:0% +a little bit of wiggle room we could + + + align:start position:0% +a little bit of wiggle room we could +move some things around without changing + + align:start position:0% +move some things around without changing + + + align:start position:0% +move some things around without changing +the optimality of the solution that is + + align:start position:0% +the optimality of the solution that is + + + align:start position:0% +the optimality of the solution that is +without changing the percent of target + + align:start position:0% +without changing the percent of target + + + align:start position:0% +without changing the percent of target +that each department received and as you + + align:start position:0% +that each department received and as you + + + align:start position:0% +that each department received and as you +see this is a little boring balanced for + + align:start position:0% +see this is a little boring balanced for + + + align:start position:0% +see this is a little boring balanced for +the ophthalmology department and the + + align:start position:0% +the ophthalmology department and the + + + align:start position:0% +the ophthalmology department and the +general surgery department so great so + + align:start position:0% +general surgery department so great so + + + align:start position:0% +general surgery department so great so +so maybe seeing that this was available + + align:start position:0% +so maybe seeing that this was available + + + align:start position:0% +so maybe seeing that this was available +then you'd go back you'd present it and + + align:start position:0% +then you'd go back you'd present it and + + + align:start position:0% +then you'd go back you'd present it and +general surgery would say well maybe + + align:start position:0% +general surgery would say well maybe + + + align:start position:0% +general surgery would say well maybe +could we have at least five per day so + + align:start position:0% +could we have at least five per day so + + + align:start position:0% +could we have at least five per day so +if you went up and changed this made it + + align:start position:0% +if you went up and changed this made it + + + align:start position:0% +if you went up and changed this made it +five all the way across instead of four + + align:start position:0% +five all the way across instead of four + + + align:start position:0% +five all the way across instead of four +and you solved it again + + align:start position:0% + + + + align:start position:0% + +what would happen you probably have an + + align:start position:0% +what would happen you probably have an + + + align:start position:0% +what would happen you probably have an +idea already + + align:start position:0% + + + + align:start position:0% + +and this is exactly what you were + + align:start position:0% +and this is exactly what you were + + + align:start position:0% +and this is exactly what you were +thinking no solution was found the model + + align:start position:0% +thinking no solution was found the model + + + align:start position:0% +thinking no solution was found the model +is infeasible check limiting conditions + + align:start position:0% +is infeasible check limiting conditions + + + align:start position:0% +is infeasible check limiting conditions +so why is the model infeasible well + + align:start position:0% +so why is the model infeasible well + + + align:start position:0% +so why is the model infeasible well +let's take a look oops + + align:start position:0% +let's take a look oops + + + align:start position:0% +let's take a look oops +scroll back over the model is infeasible + + align:start position:0% +scroll back over the model is infeasible + + + align:start position:0% +scroll back over the model is infeasible +because let's see so it's not because of + + align:start position:0% +because let's see so it's not because of + + + align:start position:0% +because let's see so it's not because of +the minimum and maximum weekly + + align:start position:0% +the minimum and maximum weekly + + + align:start position:0% +the minimum and maximum weekly +Department requirements because general + + align:start position:0% +Department requirements because general + + + align:start position:0% +Department requirements because general +surgery said that they were willing to + + align:start position:0% +surgery said that they were willing to + + + align:start position:0% +surgery said that they were willing to +have up to 25 operating rooms per week + + align:start position:0% +have up to 25 operating rooms per week + + + align:start position:0% +have up to 25 operating rooms per week +however if you look at the weekly + + align:start position:0% +however if you look at the weekly + + + align:start position:0% +however if you look at the weekly +targets 25 times 8 is 200 so if we were + + align:start position:0% +targets 25 times 8 is 200 so if we were + + + align:start position:0% +targets 25 times 8 is 200 so if we were +to actually assign general surgery 5 + + align:start position:0% +to actually assign general surgery 5 + + + align:start position:0% +to actually assign general surgery 5 +operating rooms per day we would be + + align:start position:0% +operating rooms per day we would be + + + align:start position:0% +operating rooms per day we would be +assigning them 200 hours per week which + + align:start position:0% +assigning them 200 hours per week which + + + align:start position:0% +assigning them 200 hours per week which +exceeds their weekly target and our + + align:start position:0% +exceeds their weekly target and our + + + align:start position:0% +exceeds their weekly target and our +optimization model says we cannot exceed + + align:start position:0% +optimization model says we cannot exceed + + + align:start position:0% +optimization model says we cannot exceed +the weekly targets so just right there + + align:start position:0% +the weekly targets so just right there + + + align:start position:0% +the weekly targets so just right there +we can tell that it's infeasible because + + align:start position:0% +we can tell that it's infeasible because + + + align:start position:0% +we can tell that it's infeasible because +of this constraint so let's change this + + align:start position:0% +of this constraint so let's change this + + + align:start position:0% +of this constraint so let's change this +back to 4 ok so suppose you've you know + + align:start position:0% +back to 4 ok so suppose you've you know + + + align:start position:0% +back to 4 ok so suppose you've you know +you've come up with a solution you've + + align:start position:0% +you've come up with a solution you've + + + align:start position:0% +you've come up with a solution you've +gone back to the surgical departments + + align:start position:0% +gone back to the surgical departments + + + align:start position:0% +gone back to the surgical departments +you've presented your solution they've + + align:start position:0% +you've presented your solution they've + + + align:start position:0% +you've presented your solution they've +maybe requested additional changes and + + align:start position:0% +maybe requested additional changes and + + + align:start position:0% +maybe requested additional changes and +we've made those changes here so does + + align:start position:0% +we've made those changes here so does + + + align:start position:0% +we've made those changes here so does +this mean that your job is done well no + + align:start position:0% +this mean that your job is done well no + + + align:start position:0% +this mean that your job is done well no +not really + + align:start position:0% +not really + + + align:start position:0% +not really +of course you could go back to the + + align:start position:0% +of course you could go back to the + + + align:start position:0% +of course you could go back to the +surgical departments and tell them that + + align:start position:0% +surgical departments and tell them that + + + align:start position:0% +surgical departments and tell them that +this is the schedule they're going to + + align:start position:0% +this is the schedule they're going to + + + align:start position:0% +this is the schedule they're going to +have every week but I bet if you did + + align:start position:0% +have every week but I bet if you did + + + align:start position:0% +have every week but I bet if you did +that you would hear some complaints + + align:start position:0% +that you would hear some complaints + + + align:start position:0% +that you would hear some complaints +let's go into our solution and take a + + align:start position:0% +let's go into our solution and take a + + + align:start position:0% +let's go into our solution and take a +closer look to see why so for example + + align:start position:0% +closer look to see why so for example + + + align:start position:0% +closer look to see why so for example +let's look at the ophthalmology + + align:start position:0% +let's look at the ophthalmology + + + align:start position:0% +let's look at the ophthalmology +department in our solution we're + + align:start position:0% +department in our solution we're + + + align:start position:0% +department in our solution we're +assigning them for operating rooms per + + align:start position:0% +assigning them for operating rooms per + + + align:start position:0% +assigning them for operating rooms per +week that gives them 32 weekly hours + + align:start position:0% +week that gives them 32 weekly hours + + + align:start position:0% +week that gives them 32 weekly hours +which is 81 percent of their target + + align:start position:0% +which is 81 percent of their target + + + align:start position:0% +which is 81 percent of their target +allocation hours + + align:start position:0% +allocation hours + + + align:start position:0% +allocation hours +if you assigned the schedule to off the + + align:start position:0% +if you assigned the schedule to off the + + + align:start position:0% +if you assigned the schedule to off the +malla G every week then they would never + + align:start position:0% +malla G every week then they would never + + + align:start position:0% +malla G every week then they would never +get more than 81 percent of their target + + align:start position:0% +get more than 81 percent of their target + + + align:start position:0% +get more than 81 percent of their target +allocation hours and overtime this would + + align:start position:0% +allocation hours and overtime this would + + + align:start position:0% +allocation hours and overtime this would +lead to a real shortage the reason why + + align:start position:0% +lead to a real shortage the reason why + + + align:start position:0% +lead to a real shortage the reason why +we never assign them more than 4 in our + + align:start position:0% +we never assign them more than 4 in our + + + align:start position:0% +we never assign them more than 4 in our +optimization model + + align:start position:0% +optimization model + + + align:start position:0% +optimization model +is because their weekly target number of + + align:start position:0% +is because their weekly target number of + + + align:start position:0% +is because their weekly target number of +hours was 39.4 if we had assigned them + + align:start position:0% +hours was 39.4 if we had assigned them + + + align:start position:0% +hours was 39.4 if we had assigned them +five operating rooms it would be giving + + align:start position:0% +five operating rooms it would be giving + + + align:start position:0% +five operating rooms it would be giving +them 40 hours per week which exceeds + + align:start position:0% +them 40 hours per week which exceeds + + + align:start position:0% +them 40 hours per week which exceeds +their weekly target so the way our + + align:start position:0% +their weekly target so the way our + + + align:start position:0% +their weekly target so the way our +optimization model is set up we will + + align:start position:0% +optimization model is set up we will + + + align:start position:0% +optimization model is set up we will +never give them more than four operating + + align:start position:0% +never give them more than four operating + + + align:start position:0% +never give them more than four operating +rooms per week but if you were the ORM + + align:start position:0% +rooms per week but if you were the ORM + + + align:start position:0% +rooms per week but if you were the ORM +manager you would realize that this is + + align:start position:0% +manager you would realize that this is + + + align:start position:0% +manager you would realize that this is +actually something that we should be a + + align:start position:0% +actually something that we should be a + + + align:start position:0% +actually something that we should be a +little more flexible about perhaps you + + align:start position:0% +little more flexible about perhaps you + + + align:start position:0% +little more flexible about perhaps you +would consider giving them five + + align:start position:0% +would consider giving them five + + + align:start position:0% +would consider giving them five +operating rooms one week or maybe five + + align:start position:0% +operating rooms one week or maybe five + + + align:start position:0% +operating rooms one week or maybe five +operating rooms you know every two weeks + + align:start position:0% +operating rooms you know every two weeks + + + align:start position:0% +operating rooms you know every two weeks +out of the month this is feasible + + align:start position:0% +out of the month this is feasible + + + align:start position:0% +out of the month this is feasible +because we have extra operating rooms on + + align:start position:0% +because we have extra operating rooms on + + + align:start position:0% +because we have extra operating rooms on +Thursday and Friday as you can see down + + align:start position:0% +Thursday and Friday as you can see down + + + align:start position:0% +Thursday and Friday as you can see down +here plus it seems like it's a more + + align:start position:0% +here plus it seems like it's a more + + + align:start position:0% +here plus it seems like it's a more +efficient and fair solution yes although + + align:start position:0% +efficient and fair solution yes although + + + align:start position:0% +efficient and fair solution yes although +they do exceed their weekly target by + + align:start position:0% +they do exceed their weekly target by + + + align:start position:0% +they do exceed their weekly target by +0.6 hours it means that on the weeks + + align:start position:0% +0.6 hours it means that on the weeks + + + align:start position:0% +0.6 hours it means that on the weeks +when they only get to have 81 percent of + + align:start position:0% +when they only get to have 81 percent of + + + align:start position:0% +when they only get to have 81 percent of +their target allocation they've got they + + align:start position:0% +their target allocation they've got they + + + align:start position:0% +their target allocation they've got they +know that the next week they'll be able + + align:start position:0% +know that the next week they'll be able + + + align:start position:0% +know that the next week they'll be able +to make up for it so it seems like a + + align:start position:0% +to make up for it so it seems like a + + + align:start position:0% +to make up for it so it seems like a +more fair solution as well as a more + + align:start position:0% +more fair solution as well as a more + + + align:start position:0% +more fair solution as well as a more +efficient solution by combining the + + align:start position:0% +efficient solution by combining the + + + align:start position:0% +efficient solution by combining the +power of integer optimization with the + + align:start position:0% +power of integer optimization with the + + + align:start position:0% +power of integer optimization with the +understanding and flexibility of human + + align:start position:0% +understanding and flexibility of human + + + align:start position:0% +understanding and flexibility of human +judgment you really get the best of both + + align:start position:0% +judgment you really get the best of both + + + align:start position:0% +judgment you really get the best of both +worlds \ No newline at end of file diff --git a/ocZMDMZwhCY.txt b/ocZMDMZwhCY.txt new file mode 100644 index 0000000000000000000000000000000000000000..662c73df85195bc42462b0fa496effc590ae9be8 --- /dev/null +++ b/ocZMDMZwhCY.txt @@ -0,0 +1,2594 @@ +The following +content is provided + +under a Creative +Commons license. + +Your support will help MIT +OpenCourseWare continue + +to offer high quality +educational resources for free. + +To make a donation or +view additional materials + +from hundreds of MIT courses, +visit MIT OpenCourseWare + +at ocw.mit.edu. + +PROFESSOR: Today we're going +to solve three problems, + +a problem called +Parenthesization, + +a problem called Edit Distance, +which is used in practice + +a lot, for things like +comparing two strings of DNA, + +and a problem called +Knapsack, just + +about how to pack your bags. + +And we're going to get a +couple of general ideas, + +one is about how to deal with +string problems in general + +with dynamic programming. + +The first two and +our previous lecture + +are all about strings, +certain sense or sequences, + +and we're going to introduce +a new concept, kind + +of like polynomial time, but +only kind of, sort of-- pseudo + +polynomial time. + +Remember, dynamic programming +in five easy steps. + +You define what your sub +problems are and count + +how many there are, to +solve a sub problem, + +you guess some part of the +solution, where there's not too + +many different possibilities +for that guess. + +You count them, +better be polynomial. + +Then you, using that guess-- +this is sort of optional, + +but I think it's a useful +way to think about things. + +You write a recurrence relating +the solution to the subproblem + +you want to solve, in terms of +smaller subproblem, something + +that you already +know how to solve, + +but it's got to be +within this list. + +And when you do +that, you're going + +to get a min or a max +of a bunch of options, + +those correspond +to your guesses. + +And you get some +running time, in order + +to compute that recurrence, +ignoring the recursion, that's + +time for subproblem. + +Then, to make a dynamic +program, you either just + +make that a recursive algorithm +and memoize everything, + +or you write the bottom +up version of the DP. + +They do exactly the same +computations, more or less, + +and you need to check that +this recurrence is acyclic, + +that you never end up +depending on yourself, + +otherwise these will +be infinite algorithms + +or incorrect algorithms. + +Either way is bad. + +From the bottom up, you +really like to explicitly know + +a topological order +on the subproblems, + +and that's usually +pretty easy, but you've + +got make sure that it's acyclic. + +And then, to compute the +running time of the algorithm, + +you just take the number +of subproblems from part 1 + +and you multiply it +by the time it takes + +per subproblem, ignoring +recursion, in part 3. + +That gives you +your running time. + +I've written this formula +by now three times + +are more, remember it. + +We use it all the time. + +And then you need to double +check that you can actually + +solve the original +problem you cared about, + +either it was one +of your subproblems + +or a combination of them. + +So that's what we're going +to do three times today. + +One of the hardest parts +in dynamic programming + +is step 1, defining +your subproblems. + +Usually if you do that right, +it becomes-- with some practice, + +step 2 is pretty easy. + +Step 1 is really where most +of the insight comes in, + +and step 3 is usually trivial, +once you know 1 and 2. + +Once you realize 1 and 2 will +work, the recurrence is clear. + +So I want to give you some +general tips for step 1, + +how to choose +subproblems, and we're + +going to start with problems +that involve strings + +or sequences as input, +where the problem, the input + +to the problem is +string or sequence. + +Last class we saw +text justification, + +where the input was +a sequence of words, + +and we saw Blackjack, where the +input was a sequence of cards. + +Both of these are examples, +and if you look at them, + +in both cases we +used suffixes, what + +do I call it, x, +as our subproblems. + +If x was our sequence, +we did all the suffixes, + +I equals zero up to the +length of the thing. + +So they're about n, n +plus 1, such subproblems. + +This is good. + +Not very many of them, +and usually if you're + +plucking things off the +beginning of the string + +or of the sequence, then +you'll be left with the suffix. + +If you always are plucking +from the beginning, + +you always have suffixes, +you'll stay in this class, + +and that's good, +because you always + +want a recurrence +that relates, in terms + +of the same subproblems +that you know. + +Sometimes it doesn't work. + +Sometimes prefixes +are more convenient. + +These are usually +pretty much identical, + +but if you're plucking +off from the end instead + +of the beginning, you'll end +up with prefixes, not suffixes. + +Both of these have +linear size, so they're + +good news, quite efficient. + +Another possibility +when that doesn't work, + +we're going to see an +example of that today, + +is you do all substrings. + +So I don't mean +subsequences, they + +have to be consecutive +substrains, i through j. + +And now for all i and j. + +How many of these are there? + +For a string of length n? + +N squared. + +So this one is n squared, +the others are linear. + +Out of room here. + +Theta n. + +So you obviously you prefer +to use these subproblems + +because there's fewer of +them, but if sometimes they + +don't work, then use this +one, still polynomial, still + +pretty good. + +This will get you +through most DP's. + +It's pretty simple, +but very useful. + +Let me define the next +problem we consider. + +For each of them we're going +to go through the five steps. + +So the first problem for +today is parenthesization. + +You're given an +associative expression, + +and you want to evaluate +it in some order. + +So I'm going to-- for +associative expression, + +I'm going to think of +matrix multiplication, + +and I probably want +to start at zero. + +So let's say you +have n matrices, + +you want to compute +their product. + +So you remember matrix +multiplication is not + +commutative, I can't +reorder these things. + +All I can do is, +if I want to do it + +by sequence of pairwise +multiplications, + +is I get to choose where +the parentheses are, and do + +whatever I want for +the parentheses, + +because it's associative. + +It doesn't matter where they go. + +Now it turns out if you +use straightforward matrix + +multiplication, really +any algorithm for matrix + +multiplication, it matters +how you parenthesize. + +Some will be +cheaper than others, + +and we can use +dynamic programming + +to find out which is best. + +So let me draw a simple example. + +Suppose I have a column +vector times a row + +vector times a column vector. + +And there are two ways +to compute this product. + +One is like this, and +the other is like this. + +If I compute the +product this way, + +it's every row +times every column, + +and then every row +times every column, + +and every row +times every column. + +This subresult is a square +matrix, so if these are-- say + +everything here is n, and +this will be an n by n matrix. + +Then we multiply it by a +vector and this computation + +has to take, if +you do it well, it + +will take theta n +squared time, because I + +need to compute n +squared values here, + +and then it's n squared to +do this final multiplication. + +Versus if I do it this way, +I take all the rows here, + +multiply them on all the columns +here, it's a single number, + +and then I multiply +by this column. + +This will take linear time. + +So this is better +parenthesization than this one. + +Now, I don't even +need to define in + +general for an x by y matrix, +times a y by z matrix, + +you can think about the running +time of that multiplication. + +Whatever the running time +is, dynamic programming + +can solve this problem, +as long as it only + +depends on the dimensions +of the matrices + +that you're multiplying. + +So for this problem, +there's going + +to be the issue of which +subproblems we use. + +Now we have a +sequence of matrices + +here, so we naturally think +of these as subproblems, + +but before we get to the +subproblems, let me ask you, + +what you think you should guess? + +Let's just say from the +outset, if I give you + +this entire sequence, +what feature + +of the solution of +the optimal solution + +would you like to guess? + +Can't know the whole solution, +because there's exponentially + +many ways to parenthesize. + +What's one piece +of it that you'd + +like to guess that +will make progress? + +Any idea? + +It's not so easy. + +AUDIENCE: Well, wouldn't +you need the last operation? + +PROFESSOR: What's +the last operation + +we're going to do, exactly. + +You might call it the +outermost multiplication + +or the last multiplication. + +So that's going to look like we +somehow multiply a 0 through ak + +minus 1, and then we somehow +multiply aK through an minus 1, + +and this is the last one. + +So now we have two subproblems. + +Somehow we want to multiply +this, somehow-- I mean, + +there's got to be some +last thing you do. + +I don't know what it +is, so just guess it. + +Try all possibilities for k, +it's got to be one of them, + +take the best. + +If somehow we know the optimal +way to do a0 to k minus 1 + +and the optimal way to ak to +an minus 1, then we're golden. + +Now, this looks like a prefix, +this looks like a suffix. + +So do you think we can just +combine subproblems, suffixes + +and prefixes? + +How many people think yes? + +A few? + +How many people +think no, OK, why? + +AUDIENCE: So, for example if +you split, if you were to split, + +like [INAUDIBLE]? + +PROFESSOR: Yeah. + +The very next thing +we're going to do + +is recurse on this subproblem, +recurse on this subproblem. + +When we recurse +here, we're going + +to split it into a0 to ak prime +minus 1, and ak prime minus 1, + +or ak prime to ak minus 1. + +We're going to consider +all possible partitions, + +and this thing, from +ak prime to ak minus 1, + +is not a prefix or a suffix. + +What is it? + +A substring. + +There's only one thing left. + +I claim these are usually +enough, and in this case + +substrings will be enough. + +But this is how +you can figure out + +that, ah, I'm not staying +within the family prefixes, + +I'm not staying within +the family suffixes. + +In general, you never use +both of these together. + +If you're going to need both, +you probably need substrings. + +So if just suffixes work, fine. + +If just prefixes work, +fine, but otherwise + +you're probably going +to need substrings. + +That's just a rule +of thumb, of course. + +Cool. + +So, part 1 subproblem is going +to be the optimal evaluation + +parenthesization of +ai to aj minus 1. + +So that's part of +the problem here. + +We want to do a0 to n minus 1. + +So in general, let's just +take some substring in here + +and say, well what's the +best way to multiply that, + +and that's the +sorts of subproblems + +we're getting if +we use this guess. + +And if you start with a +substring and you do this, + +you will still remain +within a substring, + +so actually I have to +revise this slightly. + +Now we're going from ai-- to +solve this subproblem, which + +is what we need to do +in the guessing step, + +we start from ai, we go to +some guest place, ak minus 1, + +then from ak up to aj minus 1. + +This is the i +colon j subproblem. + +So we guess some point in the +middle, some choice for k. + +The number of choices +for k is-- number + +of possible choices +for this guess, + +so we have to try all of them, +is like order j minus i plus 1. + +I put order in case I'm +off by 1 or something. + +But in particular +this is [INAUDIBLE]. + +And that's all we'll need. + +So that's the guess. + +Now we go to step 3, +which is the recurrence. + +And this-- we're going to +do this over and over again. + +Hopefully by the end, +it's really obvious + +how to do this recurrence. + +Let me just fix my notation, +we're going to use dp, + +I believe. + +For whatever reason, in my +notes I often write dp of ij. + +This is supposed +to be the solution + +to the subproblem i colon j. + +I want to write it recursively, +in terms of smaller + +subproblems, and I want +to minimize the cost, + +so I'm going to +write a min overall. + +And for each choice of k, so +there's going to be a for loop, + +I'm going to use Python +notation here with iterators. + +So k is going to +be in the range, + +I think range ij is correct. + +I'm going to double check +there's no off by 1's here. + +Says i plus 1j. + +I think that's probably right. + +Once I choose where +k is, where I'm + +going to split my +multiplication, + +I do the cost for +i up to k, that's + +the left multiplication, +plus the cost for k up to j, + +plus-- so those are the two +recursive multiplications. + +So then I also have to +do this outermost one. + +So how much does that cost? + +Well, it's something, +so cost of the product + +ai colon k times the +product ak colon j. + +So I'm assuming I can +compute this cost, + +not even going to try to +write down a general formula, + +you could do it, it's +not hard, it's like xyz. + +For a standard matrix +multiplication algorithm. + +But whatever algorithm +you're using, + +assuming you could figure out +the dimensions of this matrix, + +it doesn't matter +how it's computed, + +the dimensions will +always be the same. + +You compute the dimensions +of this matrix that + +will result from +that product, it's + +always going to be +the first dimension + +here, with the last +dimension there. + +And it's constant +time, you know that. + +And then if you can figure out +the cost of a multiplication + +in constant time, just +knowing the dimensions + +of these matrices, then +you could plug this + +in to this dynamic +program, and you + +will get the optimal solution. + +This is magically considering +all possible parenthesizations + +of these matrices, but magically +it does it in polynomial time. + +Because the time for +subproblem here-- + +We're spending constant +time for each iteration + +of this for loop, +because this is + +a constant time just +computing the cost. + +These are free +recursive calls, so it's + +dominated by the length of +the for loop, which we already + +said was order n, so it's +order n time for subproblem, + +ignoring recursions. + +And so when we +put this together, + +the total time is +going to be the number + +of some problems, +which I did not write. + +The number of problems +in step 1 is n squared, + +that's what we said over +here, for substrings. + +So running time is number +of subproblems, which is n + +squared, times linear for each, +and so it's order n cubed, + +it's actually theta n cubed. + +So polynomial time, +much better than trying + +all possible parenthesizations, +they're about 4 + +to the n parenthesizations, +that's a lot. + +Topological order here is +a little more interesting, + +if you think about that. + +I can tell you, for +suffixes, topological order + +is almost always right to left. + +And for prefixes, +it's almost always + +left to right, for +increasing i, decreasing i. + +For substrings, what +do you think it is? + +Or for this situation +in particular? + +In what order should I +evaluate these subproblems? + +AUDIENCE: [INAUDIBLE]. + +PROFESSOR: This is +the running time + +to determine the best way +to multiply-- that's right. + +So yeah, it's worth +checking, because we also + +have to do the multiplication. + +But if you imagine +this n, the number + +of matrices you're +multiplying is probably + +much smaller than their sizes. + +In that situation, +this will be tiny, + +whereas the time to actually +do the multiplication, that's + +what's being computed by the DP, +hopefully that's much larger, + +otherwise you're kind of +wasting your time doing the DP. + +But hey, at least you +could tell somebody + +that you did it optimally. + +But it gets into a +fun issue of cost + +of planning verses execution, +but we're not really + +going to worry about that here. + +So, in what order should I +evaluate this recurrence, + +in order to-- I want, when +I'm evaluating DP of ij, + +I've already done DP +of ik and DP of kj, + +and this is what you need +for bottom up execution. + +Yeah. + +AUDIENCE: Small to large. + +PROFESSOR: Small +to large, exactly. + +We want to do increasing +substring size. + +That's actually +what we're always + +doing for all of those +subproblems over there. + +When I say all suffixes, +you go right to left. + +Well, that's because the +rightmost suffix is nothing, + +and then you build up a larger +and larger strings, same thing + +here. + +Exercise, try to draw +the DAG for this picture. + +It's a little harder, +but if you-- I + +mean you could basically +imagine-- I'll do it for you. + +Here is, let's say-- +well, at the top + +there's everything, the +longest substring, that + +would be from zero to +n, that's everything. + +Then you're going to +have n different ways + +to have substrings +of, or actually just + +two different ways, to have +a slightly smaller substring. + +At the bottom you have +a bunch of substrings, + +which are the length zero +ones, and in between, + +like in the middle +here, you're going + +to have a much larger number. + +And all these edges +are pointed up, + +so you can compute +all the length + +zero ones without any +dependencies and then just + +increasing in length. + +It's a little hard to see, +but in each case-- Yeah, + +ah, interesting. + +This is a little harder to +formulate as a regular shortest + +paths problem, because if you +look at one of these nodes, + +it depends on two +different values, + +and you have to take +the sum of both of them. + +And then you also add +the cost of that split. + +Cool. + +So this is the subproblem +DAG, you could draw it, + +but this DP is not +shortest paths in that DAG. + +So perhaps dynamic programming +is not just shortest paths + +in a DAG, that's a +new realization for me + +as of right now. + +OK. + +Some other things +I forgot to do-- I + +didn't specify the base case. + +The base case for +that recurrence + +is when your string is of +length 0 or even of length 1, + +because when it's length +1, there's only one matrix, + +there's no multiplication to +do, and so the cost is zero. + +So you have something like dp +of i, i plus 1 equals zero. + +That's the base case. + +And then step 5, +step 5 is what's + +the overall problem +I want to solve, + +and that's just dp from 0 to +n, that's the whole string. + +Any questions about that DP? + +I didn't write down, I didn't +write down a memoized recursive + +algorithm, you all +know how to do that. + +Just do this for loop +and put this inside, + +that would be the +bottom up one, or just + +write this with +memoization, that + +would be the +recursive algorithm. + +It's totally easy once +you have this recurrence. + +All right, good. + +How many people is this +completely clear to? + +OK. + +How many people does +it kind of make sense? + +And how many people it +doesn't make sense at all? + +OK, good. + +Hopefully we're +going to shift more + +towards the first category. + +It's a little magical, how +this guessing works out, + +but I think the only way to +really get it is to see more + +examples and write +code to do it, + +that's-- the ladder +is your problem set, + +examples is what we'll do here. + +So next problem +we're going to solve. + +Dynamic programming is +one of these things that's + +really easy once you get it, +but it takes a little while + +to get there. + +So edit distance, we're going +to make things a little harder. + +Now we're going to be given two +strings instead of just one. + +And I want to know the cheapest +way to convert x into y. + +I'm going to define +what transform means. + +We're going to allow +character edits. + +We want to transform this +string x into string y, + +so what character +edits are we allowed? + +Very simple, we're allowed to +insert a character anywhere + +in the strength, we're allowed +to delete a character anywhere + +in the string, and we're allowed +to replace a character anywhere + +in the string, replace +c with c prime. + +Now, you could do a replacement +by deleting c and inserting + +c that's, one way +to do it, but I'm + +going to imagine that in +general someone tells me + +how much each of these +operations costs, + +and that cost may depend on +the character you're inserting. + +So deleting a character and then +inserting a different character + +will cost one thing. + +It will cost the sum of +those two cost values. + +Replacing a character +with another character + +might be cheaper. + +It depends. + +Someone gives me a little table, +saying for this character, + +for letter a, it costs this +much to insert, for letter + +b it costs this much to +insert, this much to delete, + +and there's a little +matrix for, if I + +want to convert an a into a b +it costs this much to replace. + +Imagine, if you +will, you're trying + +to do a spelling correction, +someone's typing on a keyboard, + +and you have some model +of, oh, well if I hit a, + +I might have meant to +hit an s, because s + +is right next to an a, +and that's an easy mistake + +to make if you're not +touch typing, because it's + +on the same finger, or maybe +you're shifted over by one. + +So you can come up +with some cost models, + +someone could do a lot +of work and research + +and whatnot and see +what are typical typos, + +replacing one +letter for another, + +and then associate some +cost for each character, + +for each pair characters, +what's the likelihood + +that that was the mistake? + +I call that the cost, +that's the unlikeliness. + +And then you want to +minimize the sum of costs, + +and so you want to find what +was the least set of errors that + +would end up with this +word instead of this word. + +You do that on all +words of your dictionary + +and then you'll +find the one that + +was most likely what +you meant to type. + +And insertions +and deletions are, + +I didn't hit the +key hard enough, + +or I hit it twice, or +accidentally hit a key + +because it was right next +to another one, or whatever. + +OK, so this is used for +spelling correction. + +It's used for comparing +DNA sequences, + +and DNA sequences, if you +have one strand of DNA, + +there's a lot of mutation-- +some mutations are + +more likely than others. + +For example, c to +a g mutation is + +more common than c +to an a mutation, + +and so you give this +replacement a high cost, + +you give this one a +low cost, to represent + +this is more likely than this. + +And then at a distance +will give your measure + +of how similar two DNA +strings are evolutionarily. + +And you also get extra +characters randomly inserted + +and deleted in mutation. + +So, it's a simplified model +of what happens in mutation, + +but still it's used a lot. + +So all these are encompassed +by edit distance. + +Another problem encompassed +by edit distance + +is the longest common +subsequence problem. + +And I have a fun example, +which I spent some hours, + +way back when, coming up with. + +I can't spell it, though. + +It's such a weird word. + +Hieroglyphology +is an English word + +and Michelangelo is +another English word, + +if you allow proper +nouns, unlike Scrabble. + +So, think of these as strings. + +This is x, this is y. + +What is the longest +common subsequence? + +So not substring, +I get to choose-- + +I can drop any set of letters +from x, drop any set of letters + +from y, and I want them +to, in the end, be equal. + +It's a puzzle for you. + +While you're thinking +about it, you + +can model this as an +edit distance problem, + +you just define the cost of +an insert or a delete to be 1, + +and the cost of a +replace to be 0. + +So this is a c to c +prime replacement. + +It's going to be 0 +if c equals c prime, + +and I guess infinity otherwise. + +You just don't consider +it in that situation. + +Can anyone find the longest +common subsequence here? + +It's in English +word, that's a hint. + +So if you do this +you're, basically + +trying to minimize number +of insertions and deletions. + +Insertions in x correspond +to deletions in y, + +and deletions in x +correspond to deletions in x. + +So this is the minimum number +of deletions in both strings, + +so you end up with +a common substring. + +Because replacement says, +I don't pay anything + +if the characters match exactly, +otherwise I pay everything. + +I'd never want to do this, +so if there's a mismatch + +I have to delete it. + +And so this model +is the same thing + +as long as common subsequence. + +I want to solve this +more general problem, + +it's actually easier to solve +the more general problem, + +but in particular, +you can use it + +to solve this tricky problem. + +Any answers? + +Yeah. + +Hello. + +Very good. + +Hello is the longest +common subsequence. + +You can imagine +how I found that. + +Searching for all +English words that + +have "hello" as the subsequence. + +That can also be done +in polynomial time. + +So how are we going to do this? + +Well, I'd like to somehow +use subproblems for strings, + +suffixes, prefixes, +or substrings. + +But now I have two strings, +that's kind of annoying. + +But don't worry, we can do +sort of dynamic programming + +simultaneously over x and y. + +What we're going to do is look +at suffixes of x and suffixes + +of y, and to make +our subproblems + +we need to combine all of those +subproblems by multiplication. + +We need to think about both +of them simultaneously. + +So subproblem is going to +be solve edit distance, + +edit distance problem on +two different strings, + +a suffix of x and a possibly +different suffix of y. + +Because this is for all +possible i and j choices. + +And so the number +of subproblems is? + +AUDIENCE: N squared. + +PROFESSOR: N squared, yes. + +If x is of length n +and y is of length n, + +there's n choices for +this, n choices for that, + +and we have to do +all of them as pairs, + +if there's n squared pairs. + +In general, if they +have different lengths, + +it's going to be the length +of x times length of y. + +It's quadratic. + +Good. + +So, next we need to +guess something, step 2. + +This is maybe not so +obvious, let's see. + +You have here's x, +starting at position i. + +You have y starting +at position j. + +Somehow I need to +convert x into y, + +I think it's probably +better if I line these up, + +even though in some sense +they're not lined up, + +that's OK. + +I want to convert x into y. + +What should I look at here? + +Well, I should look at +the very first characters, + +because we're +looking at suffixes. + +We want to cut off first +characters somehow. + +How could it-- what are the +possible ways to convert, or to + +deal with the first +character of x? + +What are the possible +things I could do? + +Given that, ultimately, I +want the first character + +of x to become the +first character of y. + +AUDIENCE: Delete [INAUDIBLE]. + +PROFESSOR: You could +delete this character + +and then insert this one, yes. + +Other things? + +There's a few possibilities. + +If you look at it right, +there are three possibilities. + +And three possibilities are +insert, delete, or replace. + +So let's figure out +how that's the case. + +I could replace this +character with that character, + +so that's one choice. + +That will make progress. + +Once I do that, I can cross +off those first characters + +and deal with the rest +of the substrings. + +Let's think about +insert and delete. + +If I wanted to +insert, presumably, I + +need this character +at some point. + +So in order to make +this character, + +if it's not going to come +from replacing this one, + +it's got to be from inserting +that character right there. + +Once I do that, I can cross out +that newly inserted character + +in this one, and then I have +all of the string x from i + +onward still, but then I've +removed one character from y, + +so that's progress. + +The other possibility +is deletion, + +so maybe I delete +this character, + +and then maybe I insert +it in the next step, + +but it could be this +character matches that one, + +or maybe I have to delete +several characters before I + +get to one that +matches, something. + +But I don't know that, +so that's hard to guess, + +because that would be +more time to guess. + +But I could say, well, this +character might get deleted. + +If it gets deleted, that's +it, it gets deleted. + +And then somehow the rest +of the x, from i plus 1 on, + +has to match with +all of y, from j on. + +But those are the +three possibilities, + +and in some sense capture +all possibilities. + +So it could be we +replace xi with yj, + +and so that has some +cost, which we're given. + +It could be that we insert +yj at the beginning, + +or it could be +that we delete xi. + +You can see that's +definitely spanning + +all the possible +operations we can do, + +and if you think +about it long enough, + +you will be +convinced this really + +covers every possible +thing you can do. + +If you think about +the optimal solution, + +it's got to do something to +make this first character. + +Either it does it by replacement +or it does it by an insertion. + +But if it inserts +it later on, it's + +got to get this out +of the way somehow, + +and that's the deletion case. + +If it inserts it at the +beginning, that's the insertion + +case, if it just +does a replacement, + +that's the replace case. + +Those are all possibilities +for the optimal solution. + +Then you can write +a recurrence, which + +is just a max of those +things, those three options. + +So I'm going to write, I +guess, dp of ij, yes, of i,j, + +but now i,j is not a substring. + +It's a suffix of x +and a suffix of y, + +so it corresponds +to this subproblem. + +If I want to solve +that subproblem, + +it's going to be the +min of three options. + +We've got the +replace case, so it's + +going to be some cost of +the replace, from xi to yj. + +So that's a quantity +which we're given. + +Plus the cost of the rest. + +So after we do this +replacement, we can cross off + +both those characters, and +so we look at i plus 1 on + +for x, and j plus +1 onwards for y. + +So that's option 1. + +Then comma for the min. + +Option 2 is we have +the cost of insert yj. + +So that's also +something we're given. + +Then we add on what we +have to do afterwards, + +which is we've just +gotten rid of yj, + +so x still has the +entire string from i on, + +and y has a smaller string. + +Comma. + +Last option is basically the +same, cost of the delete, + +deleting xi, and then we have +to add on DP of i plus 1j. + +Because here we did not +advance y but we advanced x. + +It's crucial that we +always advance at least one + +of the strings, because that +means we're making progress, + +and indeed, if you want to jump +to step 4, which is topological + +ordering-- sorry, I +reused my symbols here, + +some different symbols. + +Head back to step 4 of +DP, topological order. + +Well, these are +suffixes, and so I + +know with suffixes I like +to go from the smaller + +suffixes, which is the +end, to the beginning. + +And, indeed, because +we're always increasing, + +we're always looking at later +substrings, later suffixes, + +for one or the other. + +It's enough to just +do-- come over here. + +To just do that for +both of the strings, + +it doesn't really +matter the order. + +So you can do for i +equals x down to zero, + +for j equals y down to +zero, and that will work. + +Now this is another +dynamic programming + +you can think of as just +shortest paths in the DAG. + +The DAG is most easily seen as +a two-dimensional matrix, where + +the i index is between zero and +length of x, and the j index + +is between zero and +length of y, and each + +of the cells in this matrix +is a node in the DAG. + +That's one of our +subproblems, dp of ij. + +And it depends on these +three adjacent cells. + +The edges are like this. + +If you look at it, +we have to check i + +plus 1, j plus 1, +that's this guy. + +We have to check ij +plus 1, that's this guy. + +We have to check i plus +1j, that's this guy. + +And so, as long as we +compute the matrix this way, + +what I've done here is +row by row, bottom up. + +You could do it +anti-diagonals, you + +could do it column by column +backwards, all of those + +will work because we're making +progress towards the origin. + +And so if you ever-- if +you look up at a distance, + +most descriptions think +about it in the matrix form, + +but I think it's easier to think +of it in this recursive form, + +whatever your poison. + +But this is, again, +shortest paths in a DAG. + +The original problem +we care about + +is dp of zero zero, +the upper left corner. + +So to be clear in the +DAG, what you write here + +is like the cost of, +the weight of that edge + +is the cost of, I +believe, a deletion. + +Deletion, oh sorry, +it's an insertion. + +Inserting that character, +this one's a cost of deletion, + +this is a cost to replace, so +you just put those edge weights + +in, and then just do a +shortest paths in the DAG, + +I think, from this +corner to this corner. + +And that will give you this, or +you could just do this for loop + +and do that in the +for loop, same thing. + +OK. + +What's the running time? + +Well, the number of +subproblems here is x times y, + +the running time +for subproblem is? + +I'm assuming that I know +these costs in constant time, + +so what's the overall running +time of that, evaluating that? + +Constant. + +And so the overall running time +is the number of subproblems + +times a constant +equals x times y. + +This is the best known +algorithm for edit distance, + +no one knows how +to do any better. + +It's a big open problem +whether you can. + +You can improve the +space a little bit, + +because we really +only need to store + +the last row or the +last column, depending + +on the order you're +evaluating things. + +To even get down to linear +space, as far as we know, + +we need quadratic time. + +One more problem, are you ready? + +This one's going to blow +your minds hopefully. + +Because we're going to diverge +from strings and sequences, + +kind of. + +So far everything we've +looked at involves one or two + +strings or sequences, +except for [INAUDIBLE]. + +That involved a graph, that +was a little more exciting. + +But we'd already seen that, +so it wasn't that exciting. + +OK, our last problem +for today is knapsack. + +It's a practical problem. + +You're going camping. + +You're going backpacking, +I should say, + +and you can only +afford to take whatever + +you can fit on your back. + +You have some limit +to capacity, let's say + +one giant backpack +is all you can carry. + +Let's imagine it's the size +of the backpack that matters, + +not the weight, but +you could reformulate + +this in terms of weight. + +And you've got a lot of +stuff you want to bring. + +Ideally you bring +everything you own, + +that would be kind +of nice, convenient, + +but it'd be kind of heavy. + +So you're limited, you're +not able to do that. + +So you have a list of items and +each of them has a size, si, + +and has a desire, +a value to you, + +how much you care about it, how +much you need it on this trip. + +OK, each item has two things, +and the sizes are integers. + +This is going to be important. + +It won't work without +that assumption. + +And we have a +knapsack, backpack, + +whatever, I guess it's the +British, but I don't know, + +I get confused. + +Growing up in Canada, I use +both, so it's very confusing. + +Knapsack of total size, S. + +And what you'd like to do is +choose a subset of the items. + +If you're lucky, the sum +of the si's fit within s, + +then you bring everything. + +But if you're not lucky, +that's not possible, + +you want to choose a subset of +the items whose total size is + +less than or equal +to s, in order + +to maximize the +sum of the values. + +So you want to maximize +the sum of values + +for a subset of items, of total +size less than or equal to S. + +You can imagine size as +weights instead of size, not + +a big deal, or you could +have sizes and weights. + +All of these things generalize. + +But we're going to need that +the sizes/weights are integers. + +And so the items have to +fit, because you can't cheat, + +you can't have more +things than what fit, + +but then you want to +maximize the value. + +How do we do this with +dynamic programming? + +With difficulty. + +I don't have a ton +of time, so I think + +I'm going to tell +you-- well, let's see. + +Start with guessing. + +This is the easy +part to this problem. + +We should also be thinking about +subproblems at the same time. + +Even though I said we're +leaving sequences, in fact, + +we have a sequence here, we +have a sequence of items. + +We don't actually care about +the order of the items, but hey, + +they're in an order. + +If they weren't, we could +put them in an order, + +in an arbitrary order. + +We're going to use +that order, and we're + +going to look at +suffixes of items. + +i colon of items. + +That's helpful, because +now it says, oh, well, we + +should be plucking off +items from the beginning. + +Starting with the +i-th item, what + +should I decide +about the i-th item, + +relative to the +optimal solution? + +What should I guess? + +AUDIENCE: Is i included or not? + +PROFESSOR: Is i included +or not, exactly. + +Is item i in the subset or not. + +Two choices, easy. + +Of course, those +are the choices. + +If I do that for everybody, +then I know the entire subset. + +Somehow I need to +be able to write + +and this is what's +actually impossible + +if I choose this +as my subproblem. + +I want to write DP of i, +somehow, in terms of, I guess, + +DP of i plus 1. + +And we'd like to do max, and +either we don't put it in, + +in which case that's our value, +or we put it in, in which case + +we get an additional +v i in value. + +OK, but we consume +in size, and there's + +no way to remember that +we've consumed the size here. + +We just called DP of i plus 1. + +In this case, it has +everything, all this. + +In this case, we +lose si of S, but we + +can't represent that here. + +That's bad, this would be +an incorrect algorithm. + +I would always choose +to put everything in, + +because it's not keeping +track of the size bound. + +There's no capital S in +this formula, that's wrong. + +So, to fix that, I'm +going to write that again, + +but a subproblem is going +to have more information, + +it's going to have +an index i, and it's + +going to have +remaining capacity. + +I'm going to call it capital +X, at some integer at most + +S. We're assuming that the +sizes are all integers, + +so this is valid. + +The number of subproblems +is equal to n, + +the number of items, did +I say there are n items? + +Now there are n items, times +capital S, really S plus 1, + +because I have to +go down to zero. + +But n times S, +different subproblems. + +Now for each of them I +can write a recurrence, + +and that is DP of +i comma s, is going + +to be the max of +DP of i plus 1s. + +This is the case where we +don't include the items, + +so S stays the same. + +Actually I should write x +here, because it's not actually + +our original value of s. + +x is the general situation. + +The other possibility +is we include item i, + +and then we give DP of i plus 1. + +We still consume item i. + +We now have x minus si +as our new capacity, + +what remains after +we add in this item. + +And then we add on +vi, because that's + +the value we gain from +putting that item in. + +That's it, that's the +DP, pretty simple. + +Let me say a little bit about +the running time of this thing. + +Again, you check there's a +topological order and all + +that, it's in the notes. + +The total running time, +we spend constant time + +to evaluate this formula, +so it's super easy. + +The number of subproblems +is the bottleneck. + +So it's n times s. + +Is this polynomial time? + +You might guess from the outline +of today that the answer is no. + +This is not polynomial time. + +What this polynomial time mean? + +It's polynomial and n, where +n is the size of the input. + +What's the size +of the input here? + +Well, we're given n items, each +with a size, each with a value. + +If you think of the +sizes and values + +as being single word +items, then the size is n. + +If you think of them as +being ginormous values, + +at most, the size +of this input is + +going to be something +like n times log s, + +because if you write +it out in binary + +you would need log s, bits +to write down those numbers. + +But it is not n times s. + +This would be the binary +encoding of the input, + +but the running time is this. + +Now s is exponential in +log s, this is, at best, + +an exponential time algorithm. + +But it's really not +that bad if s is small, + +and so we call it +pseudopolynomial time. + +What does pseudopolynomial mean? + +It just means that +your polynomial + +in n, the input size, +which might be this, + +and in the numbers +that are in your input. + +Numbers here means +integers, basically, + +otherwise it's not +really well defined. + +So in this case we have +a bunch of integers, + +but in particular we have s. + +And so there's S and the si's. + +This is definitely +polynomial in n and s. + +It is the product +of n and S. So you + +think of this as +pseudoquadratic time, I guess? + +Because it's quadratic, but +one of the things is pseudo, + +meaning it is one of the +numbers in the input. + +So if the number +is big in k bits, + +so I can write down a number +that's of size 2 to the k. + +So it's kind of in between +polynomial and exponential, + +you might say. + +Polynomial good, +exponential bad, + +pseudopolynomial, +it's all right. + +That's the lesson. + +And for knapsack, this +is the best we can do, + +as we'll talk about later. + +Pseudopolynomial is really +the best you could hope for. + +So, sometimes that's +as good as you can do + +and dynamic programming +lets you do it. \ No newline at end of file diff --git a/opMnuRnfaX0.txt b/opMnuRnfaX0.txt new file mode 100644 index 0000000000000000000000000000000000000000..8cf9941dd283081929e16696a4d4d1a48b51230e --- /dev/null +++ b/opMnuRnfaX0.txt @@ -0,0 +1,14411 @@ +align:start position:0% + +the following content is provided under + + align:start position:0% +the following content is provided under + + + align:start position:0% +the following content is provided under +a Creative Commons license your support + + align:start position:0% +a Creative Commons license your support + + + align:start position:0% +a Creative Commons license your support +will help MIT OpenCourseWare continue to + + align:start position:0% +will help MIT OpenCourseWare continue to + + + align:start position:0% +will help MIT OpenCourseWare continue to +offer high quality educational resources + + align:start position:0% +offer high quality educational resources + + + align:start position:0% +offer high quality educational resources +for free + + align:start position:0% +for free + + + align:start position:0% +for free +to make a donation or view additional + + align:start position:0% +to make a donation or view additional + + + align:start position:0% +to make a donation or view additional +materials from hundreds of MIT courses + + align:start position:0% +materials from hundreds of MIT courses + + + align:start position:0% +materials from hundreds of MIT courses +visit MIT opencourseware at ocw.mit.edu + + align:start position:0% + + + + align:start position:0% + +to talk about the statistical physics of + + align:start position:0% +to talk about the statistical physics of + + + align:start position:0% +to talk about the statistical physics of +deep learning essentially so this is + + align:start position:0% +deep learning essentially so this is + + + align:start position:0% +deep learning essentially so this is +some ongoing work in my lab that was + + align:start position:0% +some ongoing work in my lab that was + + + align:start position:0% +some ongoing work in my lab that was +really motivated by trying to understand + + align:start position:0% +really motivated by trying to understand + + + align:start position:0% +really motivated by trying to understand +how neural networks and infants learn + + align:start position:0% +how neural networks and infants learn + + + align:start position:0% +how neural networks and infants learn +categories and then it sort of led to a + + align:start position:0% +categories and then it sort of led to a + + + align:start position:0% +categories and then it sort of led to a +bunch of results in in deep learning + + align:start position:0% +bunch of results in in deep learning + + + align:start position:0% +bunch of results in in deep learning +that involves two Cisco physics so I + + align:start position:0% +that involves two Cisco physics so I + + + align:start position:0% +that involves two Cisco physics so I +wanted to just introduce my my lab a + + align:start position:0% +wanted to just introduce my my lab a + + + align:start position:0% +wanted to just introduce my my lab a +little bit I'm an interloper from the + + align:start position:0% +little bit I'm an interloper from the + + + align:start position:0% +little bit I'm an interloper from the +methods and computational neuroscience + + align:start position:0% +methods and computational neuroscience + + + align:start position:0% +methods and computational neuroscience +summer school where I tend to spend a + + align:start position:0% +summer school where I tend to spend a + + + align:start position:0% +summer school where I tend to spend a +month and so there you know the the the + + align:start position:0% +month and so there you know the the the + + + align:start position:0% +month and so there you know the the the +flavor of research that we do there in + + align:start position:0% +flavor of research that we do there in + + + align:start position:0% +flavor of research that we do there in +the flavor research we do in our lab is + + align:start position:0% +the flavor research we do in our lab is + + + align:start position:0% +the flavor research we do in our lab is +sort of drilling down into neural + + align:start position:0% +sort of drilling down into neural + + + align:start position:0% +sort of drilling down into neural +mechanisms underlying well-defined + + align:start position:0% +mechanisms underlying well-defined + + + align:start position:0% +mechanisms underlying well-defined +computations and we've been working on + + align:start position:0% +computations and we've been working on + + + align:start position:0% +computations and we've been working on +that with you know I spend a lot of time + + align:start position:0% +that with you know I spend a lot of time + + + align:start position:0% +that with you know I spend a lot of time +talking to neurophysiologists especially + + align:start position:0% +talking to neurophysiologists especially + + + align:start position:0% +talking to neurophysiologists especially +at Stanford where I am so we have a + + align:start position:0% +at Stanford where I am so we have a + + + align:start position:0% +at Stanford where I am so we have a +whole bunch of collaborations going on + + align:start position:0% +whole bunch of collaborations going on + + + align:start position:0% +whole bunch of collaborations going on +now involving understanding neural + + align:start position:0% +now involving understanding neural + + + align:start position:0% +now involving understanding neural +computation so for example the retina + + align:start position:0% +computation so for example the retina + + + align:start position:0% +computation so for example the retina +itself is actually a deep neural circuit + + align:start position:0% +itself is actually a deep neural circuit + + + align:start position:0% +itself is actually a deep neural circuit +already because there's interview + + align:start position:0% +already because there's interview + + + align:start position:0% +already because there's interview +there's an intervening layer of neurons + + align:start position:0% +there's an intervening layer of neurons + + + align:start position:0% +there's an intervening layer of neurons +the bipolar cells and a broken cells + + align:start position:0% +the bipolar cells and a broken cells + + + align:start position:0% +the bipolar cells and a broken cells +that intervene between the + + align:start position:0% +that intervene between the + + + align:start position:0% +that intervene between the +photoreceptors and the ganglion cells + + align:start position:0% +photoreceptors and the ganglion cells + + + align:start position:0% +photoreceptors and the ganglion cells +and oftentimes what we do is we we shine + + align:start position:0% +and oftentimes what we do is we we shine + + + align:start position:0% +and oftentimes what we do is we we shine +light on the photoreceptors and we + + align:start position:0% +light on the photoreceptors and we + + + align:start position:0% +light on the photoreceptors and we +measure the ganglion cells but we have + + align:start position:0% +measure the ganglion cells but we have + + + align:start position:0% +measure the ganglion cells but we have +no clue what's going on in the interior + + align:start position:0% +no clue what's going on in the interior + + + align:start position:0% +no clue what's going on in the interior +so we've developed computational methods + + align:start position:0% +so we've developed computational methods + + + align:start position:0% +so we've developed computational methods +that can successfully computationally + + align:start position:0% +that can successfully computationally + + + align:start position:0% +that can successfully computationally +reconstruct what's going on in the + + align:start position:0% +reconstruct what's going on in the + + + align:start position:0% +reconstruct what's going on in the +interior of this putative deep neural + + align:start position:0% +interior of this putative deep neural + + + align:start position:0% +interior of this putative deep neural +network even though we don't have access + + align:start position:0% +network even though we don't have access + + + align:start position:0% +network even though we don't have access +to these things and we can actually + + align:start position:0% +to these things and we can actually + + + align:start position:0% +to these things and we can actually +infer the existence and properties of + + align:start position:0% +infer the existence and properties of + + + align:start position:0% +infer the existence and properties of +intermediate neurons here and those + + align:start position:0% +intermediate neurons here and those + + + align:start position:0% +intermediate neurons here and those +properties are sort of similar to what's + + align:start position:0% +properties are sort of similar to what's + + + align:start position:0% +properties are sort of similar to what's +been previously recorded when people do + + align:start position:0% +been previously recorded when people do + + + align:start position:0% +been previously recorded when people do +directly record from those say the + + align:start position:0% +directly record from those say the + + + align:start position:0% +directly record from those say the +bipolar cells in the cleansing in lab + + align:start position:0% +bipolar cells in the cleansing in lab + + + align:start position:0% +bipolar cells in the cleansing in lab +we've sort of been unraveling the the + + align:start position:0% +we've sort of been unraveling the the + + + align:start position:0% +we've sort of been unraveling the the +motions underlying underlying the + + align:start position:0% +motions underlying underlying the + + + align:start position:0% +motions underlying underlying the +computations the competitions underlying + + align:start position:0% +computations the competitions underlying + + + align:start position:0% +computations the competitions underlying +of motion vision so you know when you + + align:start position:0% +of motion vision so you know when you + + + align:start position:0% +of motion vision so you know when you +swat a fly it's really hard because they + + align:start position:0% +swat a fly it's really hard because they + + + align:start position:0% +swat a fly it's really hard because they +can really quickly detect motion coming + + align:start position:0% +can really quickly detect motion coming + + + align:start position:0% +can really quickly detect motion coming +towards it and they fly away so we've + + align:start position:0% +towards it and they fly away so we've + + + align:start position:0% +towards it and they fly away so we've +been you know there's so there's been + + align:start position:0% +been you know there's so there's been + + + align:start position:0% +been you know there's so there's been +lots of work on what kinds of algorithms + + align:start position:0% +lots of work on what kinds of algorithms + + + align:start position:0% +lots of work on what kinds of algorithms +might underlie motion estimation for + + align:start position:0% +might underlie motion estimation for + + + align:start position:0% +might underlie motion estimation for +example the Rijkaard correlator the + + align:start position:0% +example the Rijkaard correlator the + + + align:start position:0% +example the Rijkaard correlator the +Barlow Levesque model and so forth we've + + align:start position:0% +Barlow Levesque model and so forth we've + + + align:start position:0% +Barlow Levesque model and so forth we've +been applying systems identification + + align:start position:0% +been applying systems identification + + + align:start position:0% +been applying systems identification +techniques to whole grain calcium + + align:start position:0% +techniques to whole grain calcium + + + align:start position:0% +techniques to whole grain calcium +imaging data we'll whole brain meaning + + align:start position:0% +imaging data we'll whole brain meaning + + + align:start position:0% +imaging data we'll whole brain meaning +from the fly visual circuit and you know + + align:start position:0% +from the fly visual circuit and you know + + + align:start position:0% +from the fly visual circuit and you know +we find we just literally identify the + + align:start position:0% +we find we just literally identify the + + + align:start position:0% +we find we just literally identify the +computation and we find that it's sort + + align:start position:0% +computation and we find that it's sort + + + align:start position:0% +computation and we find that it's sort +of none of the above it's a mixture of + + align:start position:0% +of none of the above it's a mixture of + + + align:start position:0% +of none of the above it's a mixture of +all previous approaches so grid cells we + + align:start position:0% +all previous approaches so grid cells we + + + align:start position:0% +all previous approaches so grid cells we +have some results in grid cells so these + + align:start position:0% +have some results in grid cells so these + + + align:start position:0% +have some results in grid cells so these +are these famous cells that + + align:start position:0% +are these famous cells that + + + align:start position:0% +are these famous cells that +resulted in a Nobel Prize recently we + + align:start position:0% +resulted in a Nobel Prize recently we + + + align:start position:0% +resulted in a Nobel Prize recently we +can actually show that these grid cells + + align:start position:0% +can actually show that these grid cells + + + align:start position:0% +can actually show that these grid cells +maintain their spatial coherence because + + align:start position:0% +maintain their spatial coherence because + + + align:start position:0% +maintain their spatial coherence because +the rat and the mouse are always + + align:start position:0% +the rat and the mouse are always + + + align:start position:0% +the rat and the mouse are always +interacting with the boundaries and the + + align:start position:0% +interacting with the boundaries and the + + + align:start position:0% +interacting with the boundaries and the +boundaries actually correct the rats + + align:start position:0% +boundaries actually correct the rats + + + align:start position:0% +boundaries actually correct the rats +internal estimated position and were it + + align:start position:0% +internal estimated position and were it + + + align:start position:0% +internal estimated position and were it +not for these interactions two + + align:start position:0% +not for these interactions two + + + align:start position:0% +not for these interactions two +boundaries the grid cells would rapidly + + align:start position:0% +boundaries the grid cells would rapidly + + + align:start position:0% +boundaries the grid cells would rapidly +Tico hair decohere on the timescale of + + align:start position:0% +Tico hair decohere on the timescale of + + + align:start position:0% +Tico hair decohere on the timescale of +minutes you know like less than a minute + + align:start position:0% +minutes you know like less than a minute + + + align:start position:0% +minutes you know like less than a minute +and so it's actually quite interesting + + align:start position:0% +and so it's actually quite interesting + + + align:start position:0% +and so it's actually quite interesting +we can show that whenever the rat + + align:start position:0% +we can show that whenever the rat + + + align:start position:0% +we can show that whenever the rat +encounters they encounters a boundary it + + align:start position:0% +encounters they encounters a boundary it + + + align:start position:0% +encounters they encounters a boundary it +corrects its internal estimate of + + align:start position:0% +corrects its internal estimate of + + + align:start position:0% +corrects its internal estimate of +position perpendicular to the boundary + + align:start position:0% +position perpendicular to the boundary + + + align:start position:0% +position perpendicular to the boundary +but it doesn't parallel and it doesn't + + align:start position:0% +but it doesn't parallel and it doesn't + + + align:start position:0% +but it doesn't parallel and it doesn't +because it can because when it hits a + + align:start position:0% +because it can because when it hits a + + + align:start position:0% +because it can because when it hits a +boundary it receives no information + + align:start position:0% +boundary it receives no information + + + align:start position:0% +boundary it receives no information +about where it is parallel to the + + align:start position:0% +about where it is parallel to the + + + align:start position:0% +about where it is parallel to the +boundary but it receives information in + + align:start position:0% +boundary but it receives information in + + + align:start position:0% +boundary but it receives information in +this direction and then with the Shenoy + + align:start position:0% +this direction and then with the Shenoy + + + align:start position:0% +this direction and then with the Shenoy +lab we've been looking at I think a + + align:start position:0% +lab we've been looking at I think a + + + align:start position:0% +lab we've been looking at I think a +really major conceptual puzzle in + + align:start position:0% +really major conceptual puzzle in + + + align:start position:0% +really major conceptual puzzle in +neuroscience is why can we record from a + + align:start position:0% +neuroscience is why can we record from a + + + align:start position:0% +neuroscience is why can we record from a +hundred neurons in a circuit containing + + align:start position:0% +hundred neurons in a circuit containing + + + align:start position:0% +hundred neurons in a circuit containing +millions of neurons and do + + align:start position:0% +millions of neurons and do + + + align:start position:0% +millions of neurons and do +dimensionality direction and infer these + + align:start position:0% +dimensionality direction and infer these + + + align:start position:0% +dimensionality direction and infer these +dynamical portraits of how the you know + + align:start position:0% +dynamical portraits of how the you know + + + align:start position:0% +dynamical portraits of how the you know +try to infer the state space dynamics in + + align:start position:0% +try to infer the state space dynamics in + + + align:start position:0% +try to infer the state space dynamics in +the circuit and claim that we've + + align:start position:0% +the circuit and claim that we've + + + align:start position:0% +the circuit and claim that we've +achieved success right we're doing + + align:start position:0% +achieved success right we're doing + + + align:start position:0% +achieved success right we're doing +dramatic undersampling recording a + + align:start position:0% +dramatic undersampling recording a + + + align:start position:0% +dramatic undersampling recording a +hundred neurons out of millions how + + align:start position:0% +hundred neurons out of millions how + + + align:start position:0% +hundred neurons out of millions how +would the how would the state space + + align:start position:0% +would the how would the state space + + + align:start position:0% +would the how would the state space +dynamics that we infer change if we + + align:start position:0% +dynamics that we infer change if we + + + align:start position:0% +dynamics that we infer change if we +recorded more neurons and we can show + + align:start position:0% +recorded more neurons and we can show + + + align:start position:0% +recorded more neurons and we can show +that essentially it will not change + + align:start position:0% +that essentially it will not change + + + align:start position:0% +that essentially it will not change +because we've come up with a novel + + align:start position:0% +because we've come up with a novel + + + align:start position:0% +because we've come up with a novel +connection between the active neural + + align:start position:0% +connection between the active neural + + + align:start position:0% +connection between the active neural +measurement and the act of random + + align:start position:0% +measurement and the act of random + + + align:start position:0% +measurement and the act of random +projections so we can show that the act + + align:start position:0% +projections so we can show that the act + + + align:start position:0% +projections so we can show that the act +of recording from a hundred neurons in + + align:start position:0% +of recording from a hundred neurons in + + + align:start position:0% +of recording from a hundred neurons in +the brain is like the act of measuring a + + align:start position:0% +the brain is like the act of measuring a + + + align:start position:0% +the brain is like the act of measuring a +hundred random linear combinations of + + align:start position:0% +hundred random linear combinations of + + + align:start position:0% +hundred random linear combinations of +all neurons in the relevant brain + + align:start position:0% +all neurons in the relevant brain + + + align:start position:0% +all neurons in the relevant brain +circuit and then we can apply random + + align:start position:0% +circuit and then we can apply random + + + align:start position:0% +circuit and then we can apply random +projection 3 to give us a predictive + + align:start position:0% +projection 3 to give us a predictive + + + align:start position:0% +projection 3 to give us a predictive +theory of experimental design that tells + + align:start position:0% +theory of experimental design that tells + + + align:start position:0% +theory of experimental design that tells +us given the complexity of the task how + + align:start position:0% +us given the complexity of the task how + + + align:start position:0% +us given the complexity of the task how +many neurons would you need to record to + + align:start position:0% +many neurons would you need to record to + + + align:start position:0% +many neurons would you need to record to +correctly recover the state space + + align:start position:0% +correctly recover the state space + + + align:start position:0% +correctly recover the state space +dynamics of the circuit and then in the + + align:start position:0% +dynamics of the circuit and then in the + + + align:start position:0% +dynamics of the circuit and then in the +Raymond lab at Stanford we've been + + align:start position:0% +Raymond lab at Stanford we've been + + + align:start position:0% +Raymond lab at Stanford we've been +looking at houseing synaptic plasticity + + align:start position:0% +looking at houseing synaptic plasticity + + + align:start position:0% +looking at houseing synaptic plasticity +can either enhance or impair learning + + align:start position:0% +can either enhance or impair learning + + + align:start position:0% +can either enhance or impair learning +depending on experience so for example + + align:start position:0% +depending on experience so for example + + + align:start position:0% +depending on experience so for example +we know that we think that synaptic + + align:start position:0% +we know that we think that synaptic + + + align:start position:0% +we know that we think that synaptic +plasticity underlies the very basis of + + align:start position:0% +plasticity underlies the very basis of + + + align:start position:0% +plasticity underlies the very basis of +our ability to learn and remember so you + + align:start position:0% +our ability to learn and remember so you + + + align:start position:0% +our ability to learn and remember so you +might think that enhancing synaptic + + align:start position:0% +might think that enhancing synaptic + + + align:start position:0% +might think that enhancing synaptic +plasticity through various + + align:start position:0% +plasticity through various + + + align:start position:0% +plasticity through various +pharmacological or genetic genetic + + align:start position:0% +pharmacological or genetic genetic + + + align:start position:0% +pharmacological or genetic genetic +modifications might enhance our ability + + align:start position:0% +modifications might enhance our ability + + + align:start position:0% +modifications might enhance our ability +to learn learn and remember but previous + + align:start position:0% +to learn learn and remember but previous + + + align:start position:0% +to learn learn and remember but previous +results have been mixed when you perturb + + align:start position:0% +results have been mixed when you perturb + + + align:start position:0% +results have been mixed when you perturb +synaptic plasticity sometimes you + + align:start position:0% +synaptic plasticity sometimes you + + + align:start position:0% +synaptic plasticity sometimes you +enhance learning + + align:start position:0% +enhance learning + + + align:start position:0% +enhance learning +sometimes you impair learning + + align:start position:0% +sometimes you impair learning + + + align:start position:0% +sometimes you impair learning +so I believe in the Raymond lab they're + + align:start position:0% +so I believe in the Raymond lab they're + + + align:start position:0% +so I believe in the Raymond lab they're +the first to show that in the same + + align:start position:0% +the first to show that in the same + + + align:start position:0% +the first to show that in the same +subject enhancing synaptic plasticity + + align:start position:0% +subject enhancing synaptic plasticity + + + align:start position:0% +subject enhancing synaptic plasticity +for example the cerebellum can either + + align:start position:0% +for example the cerebellum can either + + + align:start position:0% +for example the cerebellum can either +enhance or impair learning depending in + + align:start position:0% +enhance or impair learning depending in + + + align:start position:0% +enhance or impair learning depending in +the history of prior experience and we + + align:start position:0% +the history of prior experience and we + + + align:start position:0% +the history of prior experience and we +can show that in order to explain the + + align:start position:0% +can show that in order to explain the + + + align:start position:0% +can show that in order to explain the +behavioral learning curves you need much + + align:start position:0% +behavioral learning curves you need much + + + align:start position:0% +behavioral learning curves you need much +more complex than optic dynamics than + + align:start position:0% +more complex than optic dynamics than + + + align:start position:0% +more complex than optic dynamics than +people naturally assume we have to + + align:start position:0% +people naturally assume we have to + + + align:start position:0% +people naturally assume we have to +really promote our notion of what a + + align:start position:0% +really promote our notion of what a + + + align:start position:0% +really promote our notion of what a +synapse is from a single scalar like a W + + align:start position:0% +synapse is from a single scalar like a W + + + align:start position:0% +synapse is from a single scalar like a W +IJ in a neural network to an entire + + align:start position:0% +IJ in a neural network to an entire + + + align:start position:0% +IJ in a neural network to an entire +dynamical system in its own right so + + align:start position:0% +dynamical system in its own right so + + + align:start position:0% +dynamical system in its own right so +this relates to view our learning so + + align:start position:0% +this relates to view our learning so + + + align:start position:0% +this relates to view our learning so +this is sort of the low-level stuff that + + align:start position:0% +this is sort of the low-level stuff that + + + align:start position:0% +this is sort of the low-level stuff that +we've been doing I know that in this + + align:start position:0% +we've been doing I know that in this + + + align:start position:0% +we've been doing I know that in this +course you guys study a higher level + + align:start position:0% +course you guys study a higher level + + + align:start position:0% +course you guys study a higher level +stuff so I'm not going to talk about any + + align:start position:0% +stuff so I'm not going to talk about any + + + align:start position:0% +stuff so I'm not going to talk about any +of these that each of them could be like + + align:start position:0% +of these that each of them could be like + + + align:start position:0% +of these that each of them could be like +a one-hour talk but I wanted to discuss + + align:start position:0% +a one-hour talk but I wanted to discuss + + + align:start position:0% +a one-hour talk but I wanted to discuss +some more high level stuff that we've + + align:start position:0% +some more high level stuff that we've + + + align:start position:0% +some more high level stuff that we've +been doing + + align:start position:0% +been doing + + + align:start position:0% +been doing +oh sorry and the other sorry the other + + align:start position:0% +oh sorry and the other sorry the other + + + align:start position:0% +oh sorry and the other sorry the other +sort of direction in our lab that we're + + align:start position:0% +sort of direction in our lab that we're + + + align:start position:0% +sort of direction in our lab that we're +looking at is actually the statistical + + align:start position:0% +looking at is actually the statistical + + + align:start position:0% +looking at is actually the statistical +mechanics of high dimensional data + + align:start position:0% +mechanics of high dimensional data + + + align:start position:0% +mechanics of high dimensional data +analysis so this is of course very + + align:start position:0% +analysis so this is of course very + + + align:start position:0% +analysis so this is of course very +relevant and the age of the brain + + align:start position:0% +relevant and the age of the brain + + + align:start position:0% +relevant and the age of the brain +initiative and so on we're developing + + align:start position:0% +initiative and so on we're developing + + + align:start position:0% +initiative and so on we're developing +very large scale data sets and we'd like + + align:start position:0% +very large scale data sets and we'd like + + + align:start position:0% +very large scale data sets and we'd like +to extract theories from this so-called + + align:start position:0% +to extract theories from this so-called + + + align:start position:0% +to extract theories from this so-called +big data so the entire edifice of + + align:start position:0% +big data so the entire edifice of + + + align:start position:0% +big data so the entire edifice of +classical statistics is predicated on + + align:start position:0% +classical statistics is predicated on + + + align:start position:0% +classical statistics is predicated on +the assumption that you have many many + + align:start position:0% +the assumption that you have many many + + + align:start position:0% +the assumption that you have many many +data points and you have a small number + + align:start position:0% +data points and you have a small number + + + align:start position:0% +data points and you have a small number +of features right so then it's very easy + + align:start position:0% +of features right so then it's very easy + + + align:start position:0% +of features right so then it's very easy +to see patterns in your data but what's + + align:start position:0% +to see patterns in your data but what's + + + align:start position:0% +to see patterns in your data but what's +actually happening nowadays is that we + + align:start position:0% +actually happening nowadays is that we + + + align:start position:0% +actually happening nowadays is that we +have a large number of data points and a + + align:start position:0% +have a large number of data points and a + + + align:start position:0% +have a large number of data points and a +large number of features so for example + + align:start position:0% +large number of features so for example + + + align:start position:0% +large number of features so for example +where you can record from a hundred + + align:start position:0% +where you can record from a hundred + + + align:start position:0% +where you can record from a hundred +neurons using electrophysiology maybe + + align:start position:0% +neurons using electrophysiology maybe + + + align:start position:0% +neurons using electrophysiology maybe +for only a hundred trials of any given + + align:start position:0% +for only a hundred trials of any given + + + align:start position:0% +for only a hundred trials of any given +trial type in a monkey doing some tasks + + align:start position:0% +trial type in a monkey doing some tasks + + + align:start position:0% +trial type in a monkey doing some tasks +so the ratio of the amount of data to + + align:start position:0% +so the ratio of the amount of data to + + + align:start position:0% +so the ratio of the amount of data to +the the number of the number of features + + align:start position:0% +the the number of the number of features + + + align:start position:0% +the the number of the number of features +is something that's order one so you + + align:start position:0% +is something that's order one so you + + + align:start position:0% +is something that's order one so you +know the data sets are like three points + + align:start position:0% +know the data sets are like three points + + + align:start position:0% +know the data sets are like three points +in a three-dimensional space that's the + + align:start position:0% +in a three-dimensional space that's the + + + align:start position:0% +in a three-dimensional space that's the +best we can visualize so it's a + + align:start position:0% +best we can visualize so it's a + + + align:start position:0% +best we can visualize so it's a +significant challenge to do data + + align:start position:0% +significant challenge to do data + + + align:start position:0% +significant challenge to do data +analysis in this scenario so it turns + + align:start position:0% +analysis in this scenario so it turns + + + align:start position:0% +analysis in this scenario so it turns +out there's beautiful connections + + align:start position:0% +out there's beautiful connections + + + align:start position:0% +out there's beautiful connections +between machine learning and data + + align:start position:0% +between machine learning and data + + + align:start position:0% +between machine learning and data +analysis and the statistical physics of + + align:start position:0% +analysis and the statistical physics of + + + align:start position:0% +analysis and the statistical physics of +systems of the quench disorder so so + + align:start position:0% +systems of the quench disorder so so + + + align:start position:0% +systems of the quench disorder so so +what I mean by that is in data analysis + + align:start position:0% +what I mean by that is in data analysis + + + align:start position:0% +what I mean by that is in data analysis +you want to learn statistical parameters + + align:start position:0% +you want to learn statistical parameters + + + align:start position:0% +you want to learn statistical parameters +by maximizing the log likelihood of the + + align:start position:0% +by maximizing the log likelihood of the + + + align:start position:0% +by maximizing the log likelihood of the +data given the parameters and Cisco + + align:start position:0% +data given the parameters and Cisco + + + align:start position:0% +data given the parameters and Cisco +physics you often want to minimize an + + align:start position:0% +physics you often want to minimize an + + + align:start position:0% +physics you often want to minimize an +you know this can be viewed as energy + + align:start position:0% +you know this can be viewed as energy + + + align:start position:0% +you know this can be viewed as energy +minimization and so there's beautiful + + align:start position:0% +minimization and so there's beautiful + + + align:start position:0% +minimization and so there's beautiful +connections between these and so we work + + align:start position:0% +connections between these and so we work + + + align:start position:0% +connections between these and so we work +on that so we've applied this to + + align:start position:0% +on that so we've applied this to + + + align:start position:0% +on that so we've applied this to +compress sensing we've applied this to + + align:start position:0% +compress sensing we've applied this to + + + align:start position:0% +compress sensing we've applied this to +the problem of what's the optimal + + align:start position:0% +the problem of what's the optimal + + + align:start position:0% +the problem of what's the optimal +inference procedure in a written + + align:start position:0% +inference procedure in a written + + + align:start position:0% +inference procedure in a written +in a regime in the high-dimensional + + align:start position:0% +in a regime in the high-dimensional + + + align:start position:0% +in a regime in the high-dimensional +regime we know that maximum likelihood + + align:start position:0% +regime we know that maximum likelihood + + + align:start position:0% +regime we know that maximum likelihood +is optimal in this regime but something + + align:start position:0% +is optimal in this regime but something + + + align:start position:0% +is optimal in this regime but something +else is better in this regime and we + + align:start position:0% +else is better in this regime and we + + + align:start position:0% +else is better in this regime and we +found what's better it turns out to be a + + align:start position:0% +found what's better it turns out to be a + + + align:start position:0% +found what's better it turns out to be a +smooth maximum likelihood and of course + + align:start position:0% +smooth maximum likelihood and of course + + + align:start position:0% +smooth maximum likelihood and of course +we've applied this to a theory of neural + + align:start position:0% +we've applied this to a theory of neural + + + align:start position:0% +we've applied this to a theory of neural +dimensionality and measurement so you + + align:start position:0% +dimensionality and measurement so you + + + align:start position:0% +dimensionality and measurement so you +know there's lots of beautiful + + align:start position:0% +know there's lots of beautiful + + + align:start position:0% +know there's lots of beautiful +interactions between physics machine + + align:start position:0% +interactions between physics machine + + + align:start position:0% +interactions between physics machine +learning and neuroscience and and you + + align:start position:0% +learning and neuroscience and and you + + + align:start position:0% +learning and neuroscience and and you +know this school is a lot about that if + + align:start position:0% +know this school is a lot about that if + + + align:start position:0% +know this school is a lot about that if +you're interested actually we wrote like + + align:start position:0% +you're interested actually we wrote like + + + align:start position:0% +you're interested actually we wrote like +a 70 page review on statistical + + align:start position:0% +a 70 page review on statistical + + + align:start position:0% +a 70 page review on statistical +mechanics of complex neural systems and + + align:start position:0% +mechanics of complex neural systems and + + + align:start position:0% +mechanics of complex neural systems and +high dimensional data we cover a whole + + align:start position:0% +high dimensional data we cover a whole + + + align:start position:0% +high dimensional data we cover a whole +bunch of things like spin glasses the + + align:start position:0% +bunch of things like spin glasses the + + + align:start position:0% +bunch of things like spin glasses the +statistical mechanics of learning random + + align:start position:0% +statistical mechanics of learning random + + + align:start position:0% +statistical mechanics of learning random +matrix theory random dimensional + + align:start position:0% +matrix theory random dimensional + + + align:start position:0% +matrix theory random dimensional +reduction compressed sensing and so on + + align:start position:0% +reduction compressed sensing and so on + + + align:start position:0% +reduction compressed sensing and so on +and so forth it was our attempt to sort + + align:start position:0% +and so forth it was our attempt to sort + + + align:start position:0% +and so forth it was our attempt to sort +of put some systematic order on the + + align:start position:0% +of put some systematic order on the + + + align:start position:0% +of put some systematic order on the +diversity of topics viewed through the + + align:start position:0% +diversity of topics viewed through the + + + align:start position:0% +diversity of topics viewed through the +lens of statistical physics but what do + + align:start position:0% +lens of statistical physics but what do + + + align:start position:0% +lens of statistical physics but what do +I want to talk about today and why did I + + align:start position:0% +I want to talk about today and why did I + + + align:start position:0% +I want to talk about today and why did I +decide to branch out in the direction + + align:start position:0% +decide to branch out in the direction + + + align:start position:0% +decide to branch out in the direction +I'm going to tell you about well I think + + align:start position:0% +I'm going to tell you about well I think + + + align:start position:0% +I'm going to tell you about well I think +there's lots of motivations for an + + align:start position:0% +there's lots of motivations for an + + + align:start position:0% +there's lots of motivations for an +alliance between theoretical + + align:start position:0% +alliance between theoretical + + + align:start position:0% +alliance between theoretical +neuroscience theoretical machine + + align:start position:0% +neuroscience theoretical machine + + + align:start position:0% +neuroscience theoretical machine +learning that lead to opportunities for + + align:start position:0% +learning that lead to opportunities for + + + align:start position:0% +learning that lead to opportunities for +physics and math and so on so and this + + align:start position:0% +physics and math and so on so and this + + + align:start position:0% +physics and math and so on so and this +is the question that should haunt all of + + align:start position:0% +is the question that should haunt all of + + + align:start position:0% +is the question that should haunt all of +us right the question is what does it + + align:start position:0% +us right the question is what does it + + + align:start position:0% +us right the question is what does it +even mean to understand how the brain + + align:start position:0% +even mean to understand how the brain + + + align:start position:0% +even mean to understand how the brain +works or how a neural circuit works okay + + align:start position:0% +works or how a neural circuit works okay + + + align:start position:0% +works or how a neural circuit works okay +you know it that's an open question that + + align:start position:0% +you know it that's an open question that + + + align:start position:0% +you know it that's an open question that +we really have to come to terms with a + + align:start position:0% +we really have to come to terms with a + + + align:start position:0% +we really have to come to terms with a +proximal sort of a specification or a + + align:start position:0% +proximal sort of a specification or a + + + align:start position:0% +proximal sort of a specification or a +more concrete version of this question + + align:start position:0% +more concrete version of this question + + + align:start position:0% +more concrete version of this question +might be or a specification this + + align:start position:0% +might be or a specification this + + + align:start position:0% +might be or a specification this +question might be we will understand + + align:start position:0% +question might be we will understand + + + align:start position:0% +question might be we will understand +this when we understand how the + + align:start position:0% +this when we understand how the + + + align:start position:0% +this when we understand how the +connectivity and dynamics of a neural + + align:start position:0% +connectivity and dynamics of a neural + + + align:start position:0% +connectivity and dynamics of a neural +circuit give rise to behavior and also + + align:start position:0% +circuit give rise to behavior and also + + + align:start position:0% +circuit give rise to behavior and also +how neural activity and synaptic + + align:start position:0% +how neural activity and synaptic + + + align:start position:0% +how neural activity and synaptic +learning rules conspire to self-organize + + align:start position:0% +learning rules conspire to self-organize + + + align:start position:0% +learning rules conspire to self-organize +useful connectivity that's observes + + align:start position:0% +useful connectivity that's observes + + + align:start position:0% +useful connectivity that's observes +behavior okay so so you know the you + + align:start position:0% +behavior okay so so you know the you + + + align:start position:0% +behavior okay so so you know the you +know various brain interests are + + align:start position:0% +know various brain interests are + + + align:start position:0% +know various brain interests are +promising to give us recording some + + align:start position:0% +promising to give us recording some + + + align:start position:0% +promising to give us recording some +large numbers of neurons and even give + + align:start position:0% +large numbers of neurons and even give + + + align:start position:0% +large numbers of neurons and even give +us the connectivity between those + + align:start position:0% +us the connectivity between those + + + align:start position:0% +us the connectivity between those +neurons now what what if theorists own + + align:start position:0% +neurons now what what if theorists own + + + align:start position:0% +neurons now what what if theorists own +often what theorists in competition + + align:start position:0% +often what theorists in competition + + + align:start position:0% +often what theorists in competition +neuroscience do is they they often + + align:start position:0% +neuroscience do is they they often + + + align:start position:0% +neuroscience do is they they often +develop theories of random networks that + + align:start position:0% +develop theories of random networks that + + + align:start position:0% +develop theories of random networks that +have no function but what we would like + + align:start position:0% +have no function but what we would like + + + align:start position:0% +have no function but what we would like +to do is we'd like to understand + + align:start position:0% +to do is we'd like to understand + + + align:start position:0% +to do is we'd like to understand +engineered networks that have function + + align:start position:0% +engineered networks that have function + + + align:start position:0% +engineered networks that have function +so the field of machine learning has + + align:start position:0% +so the field of machine learning has + + + align:start position:0% +so the field of machine learning has +generated a plethora of learn neural + + align:start position:0% +generated a plethora of learn neural + + + align:start position:0% +generated a plethora of learn neural +networks that accomplish interesting + + align:start position:0% +networks that accomplish interesting + + + align:start position:0% +networks that accomplish interesting +functions yet we still don't have a + + align:start position:0% +functions yet we still don't have a + + + align:start position:0% +functions yet we still don't have a +meaningful understanding of how their + + align:start position:0% +meaningful understanding of how their + + + align:start position:0% +meaningful understanding of how their +connectivity dynamics the learning + + align:start position:0% +connectivity dynamics the learning + + + align:start position:0% +connectivity dynamics the learning +the developmental experience okay so + + align:start position:0% +the developmental experience okay so + + + align:start position:0% +the developmental experience okay so +basically we can measure anything we + + align:start position:0% +basically we can measure anything we + + + align:start position:0% +basically we can measure anything we +want in in these artificial neural + + align:start position:0% +want in in these artificial neural + + + align:start position:0% +want in in these artificial neural +networks right we can measure the + + align:start position:0% +networks right we can measure the + + + align:start position:0% +networks right we can measure the +connectivity between all the neurons we + + align:start position:0% +connectivity between all the neurons we + + + align:start position:0% +connectivity between all the neurons we +know the dynamics of all the neurons we + + align:start position:0% +know the dynamics of all the neurons we + + + align:start position:0% +know the dynamics of all the neurons we +know the learning rule we know the + + align:start position:0% +know the learning rule we know the + + + align:start position:0% +know the learning rule we know the +entire developmental experience the + + align:start position:0% +entire developmental experience the + + + align:start position:0% +entire developmental experience the +network because we know the training + + align:start position:0% +network because we know the training + + + align:start position:0% +network because we know the training +data that was exposed to yet we still do + + align:start position:0% +data that was exposed to yet we still do + + + align:start position:0% +data that was exposed to yet we still do +not have a meaningful understanding of + + align:start position:0% +not have a meaningful understanding of + + + align:start position:0% +not have a meaningful understanding of +how they learn and how they work and if + + align:start position:0% +how they learn and how they work and if + + + align:start position:0% +how they learn and how they work and if +we can't solve that problem how are we + + align:start position:0% +we can't solve that problem how are we + + + align:start position:0% +we can't solve that problem how are we +ever going to understand the brain right + + align:start position:0% +ever going to understand the brain right + + + align:start position:0% +ever going to understand the brain right +in the form of this question okay so + + align:start position:0% +in the form of this question okay so + + + align:start position:0% +in the form of this question okay so +that was sort of what was motivating me + + align:start position:0% +that was sort of what was motivating me + + + align:start position:0% +that was sort of what was motivating me +to look into this so so this is the + + align:start position:0% +to look into this so so this is the + + + align:start position:0% +to look into this so so this is the +outline of the talk the original entry + + align:start position:0% +outline of the talk the original entry + + + align:start position:0% +outline of the talk the original entry +point was trying to understand category + + align:start position:0% +point was trying to understand category + + + align:start position:0% +point was trying to understand category +learning in neural networks and then at + + align:start position:0% +learning in neural networks and then at + + + align:start position:0% +learning in neural networks and then at +the end of the day we made actually + + align:start position:0% +the end of the day we made actually + + + align:start position:0% +the end of the day we made actually +several theoretical advances that led to + + align:start position:0% +several theoretical advances that led to + + + align:start position:0% +several theoretical advances that led to +advances in machine learning and + + align:start position:0% +advances in machine learning and + + + align:start position:0% +advances in machine learning and +applications to engineering so for + + align:start position:0% +applications to engineering so for + + + align:start position:0% +applications to engineering so for +example we find we found random weight + + align:start position:0% +example we find we found random weight + + + align:start position:0% +example we find we found random weight +initializations that make a network + + align:start position:0% +initializations that make a network + + + align:start position:0% +initializations that make a network +dynamically critical and allow very very + + align:start position:0% +dynamically critical and allow very very + + + align:start position:0% +dynamically critical and allow very very +rapid training of deep neural networks + + align:start position:0% +rapid training of deep neural networks + + + align:start position:0% +rapid training of deep neural networks +we were able to understand and exploit + + align:start position:0% +we were able to understand and exploit + + + align:start position:0% +we were able to understand and exploit +the geometry of high dimensional error + + align:start position:0% +the geometry of high dimensional error + + + align:start position:0% +the geometry of high dimensional error +surfaces to again speed up learning like + + align:start position:0% +surfaces to again speed up learning like + + + align:start position:0% +surfaces to again speed up learning like +training deep neural networks and we're + + align:start position:0% +training deep neural networks and we're + + + align:start position:0% +training deep neural networks and we're +also able to exploit sort of recent work + + align:start position:0% +also able to exploit sort of recent work + + + align:start position:0% +also able to exploit sort of recent work +in non-equilibrium thermodynamics to + + align:start position:0% +in non-equilibrium thermodynamics to + + + align:start position:0% +in non-equilibrium thermodynamics to +learn complex probabilistic generative + + align:start position:0% +learn complex probabilistic generative + + + align:start position:0% +learn complex probabilistic generative +models so it's a diversity of topics but + + align:start position:0% +models so it's a diversity of topics but + + + align:start position:0% +models so it's a diversity of topics but +I'll walk you through them and you can + + align:start position:0% +I'll walk you through them and you can + + + align:start position:0% +I'll walk you through them and you can +relax because almost everything I'm + + align:start position:0% +relax because almost everything I'm + + + align:start position:0% +relax because almost everything I'm +going to talk about is is is published + + align:start position:0% +going to talk about is is is published + + + align:start position:0% +going to talk about is is is published +okay so let's start with the motivation + + align:start position:0% +okay so let's start with the motivation + + + align:start position:0% +okay so let's start with the motivation +a mathematical theory of semantic + + align:start position:0% +a mathematical theory of semantic + + + align:start position:0% +a mathematical theory of semantic +development I think this speaks to some + + align:start position:0% +development I think this speaks to some + + + align:start position:0% +development I think this speaks to some +of the high-level stuff that you guys + + align:start position:0% +of the high-level stuff that you guys + + + align:start position:0% +of the high-level stuff that you guys +think about this part could equally be + + align:start position:0% +think about this part could equally be + + + align:start position:0% +think about this part could equally be +talked it could could be called the + + align:start position:0% +talked it could could be called the + + + align:start position:0% +talked it could could be called the +misadventures and implied physicists who + + align:start position:0% +misadventures and implied physicists who + + + align:start position:0% +misadventures and implied physicists who +found himself lost in the psychology + + align:start position:0% +found himself lost in the psychology + + + align:start position:0% +found himself lost in the psychology +department so I sort of showed up at + + align:start position:0% +department so I sort of showed up at + + + align:start position:0% +department so I sort of showed up at +Stanford Jay's a great guy was talking + + align:start position:0% +Stanford Jay's a great guy was talking + + + align:start position:0% +Stanford Jay's a great guy was talking +to him and I learned about his work and + + align:start position:0% +to him and I learned about his work and + + + align:start position:0% +to him and I learned about his work and +I realized I didn't understand it + + align:start position:0% +I realized I didn't understand it + + + align:start position:0% +I realized I didn't understand it +and and this is my attempt to understand + + align:start position:0% +and and this is my attempt to understand + + + align:start position:0% +and and this is my attempt to understand +that work with Andrew and NJ so ok so + + align:start position:0% +that work with Andrew and NJ so ok so + + + align:start position:0% +that work with Andrew and NJ so ok so +what is semantic cognition so human + + align:start position:0% +what is semantic cognition so human + + + align:start position:0% +what is semantic cognition so human +semantic cognition a rough definition of + + align:start position:0% +semantic cognition a rough definition of + + + align:start position:0% +semantic cognition a rough definition of +this field is that we have an ability to + + align:start position:0% +this field is that we have an ability to + + + align:start position:0% +this field is that we have an ability to +learn recognize comprehend and produce + + align:start position:0% +learn recognize comprehend and produce + + + align:start position:0% +learn recognize comprehend and produce +inferences about properties of objects + + align:start position:0% +inferences about properties of objects + + + align:start position:0% +inferences about properties of objects +and events in the world especially + + align:start position:0% +and events in the world especially + + + align:start position:0% +and events in the world especially +properties that are not present in your + + align:start position:0% +properties that are not present in your + + + align:start position:0% +properties that are not present in your +current perceptual stimulus so for + + align:start position:0% +current perceptual stimulus so for + + + align:start position:0% +current perceptual stimulus so for +example I can ask you does a cat have + + align:start position:0% +example I can ask you does a cat have + + + align:start position:0% +example I can ask you does a cat have +fur and do birds fly and you can answer + + align:start position:0% +fur and do birds fly and you can answer + + + align:start position:0% +fur and do birds fly and you can answer +these questions correctly despite the + + align:start position:0% +these questions correctly despite the + + + align:start position:0% +these questions correctly despite the +fact that there's currently no cat or + + align:start position:0% +fact that there's currently no cat or + + + align:start position:0% +fact that there's currently no cat or +bird in the room + + align:start position:0% +bird in the room + + + align:start position:0% +bird in the room +right so you know our ability to do this + + align:start position:0% +right so you know our ability to do this + + + align:start position:0% +right so you know our ability to do this +likely relies on our ability to form + + align:start position:0% +likely relies on our ability to form + + + align:start position:0% +likely relies on our ability to form +internal representations of categories + + align:start position:0% +internal representations of categories + + + align:start position:0% +internal representations of categories +in the external world and associate + + align:start position:0% +in the external world and associate + + + align:start position:0% +in the external world and associate +properties with those categories because + + align:start position:0% +properties with those categories because + + + align:start position:0% +properties with those categories because +we never see the same stimulus twice so + + align:start position:0% +we never see the same stimulus twice so + + + align:start position:0% +we never see the same stimulus twice so +whenever we see a new stimulus or we + + align:start position:0% +whenever we see a new stimulus or we + + + align:start position:0% +whenever we see a new stimulus or we +trying to recall information from our + + align:start position:0% +trying to recall information from our + + + align:start position:0% +trying to recall information from our +brain we rapidly identify the relevant + + align:start position:0% +brain we rapidly identify the relevant + + + align:start position:0% +brain we rapidly identify the relevant +category that contains the information + + align:start position:0% +category that contains the information + + + align:start position:0% +category that contains the information +and we use that categorical + + align:start position:0% +and we use that categorical + + + align:start position:0% +and we use that categorical +representation to guide future actions + + align:start position:0% +representation to guide future actions + + + align:start position:0% +representation to guide future actions +or give answers right so a category + + align:start position:0% +or give answers right so a category + + + align:start position:0% +or give answers right so a category +formation is central to this right so + + align:start position:0% +formation is central to this right so + + + align:start position:0% +formation is central to this right so +what are the kinds of psychophysical + + align:start position:0% +what are the kinds of psychophysical + + + align:start position:0% +what are the kinds of psychophysical +tasks that people use to probe semantic + + align:start position:0% +tasks that people use to probe semantic + + + align:start position:0% +tasks that people use to probe semantic +cognition so this is a very rich field + + align:start position:0% +cognition so this is a very rich field + + + align:start position:0% +cognition so this is a very rich field +psychologists have been working on this + + align:start position:0% +psychologists have been working on this + + + align:start position:0% +psychologists have been working on this +all the time so one example is looking + + align:start position:0% +all the time so one example is looking + + + align:start position:0% +all the time so one example is looking +time studies to ascertain whether or not + + align:start position:0% +time studies to ascertain whether or not + + + align:start position:0% +time studies to ascertain whether or not +an infant can distinguish between two + + align:start position:0% +an infant can distinguish between two + + + align:start position:0% +an infant can distinguish between two +categories of objects at what age so for + + align:start position:0% +categories of objects at what age so for + + + align:start position:0% +categories of objects at what age so for +example they'll show a sequence of + + align:start position:0% +example they'll show a sequence of + + + align:start position:0% +example they'll show a sequence of +objects from category one say horses and + + align:start position:0% +objects from category one say horses and + + + align:start position:0% +objects from category one say horses and +the first time the infant sees a horse + + align:start position:0% +the first time the infant sees a horse + + + align:start position:0% +the first time the infant sees a horse +the looking time will go up and then it + + align:start position:0% +the looking time will go up and then it + + + align:start position:0% +the looking time will go up and then it +goes down over time it gets bored then + + align:start position:0% +goes down over time it gets bored then + + + align:start position:0% +goes down over time it gets bored then +you show a cow and if the infant is old + + align:start position:0% +you show a cow and if the infant is old + + + align:start position:0% +you show a cow and if the infant is old +enough the looking time will go up and + + align:start position:0% +enough the looking time will go up and + + + align:start position:0% +enough the looking time will go up and +then go back down and that's from that + + align:start position:0% +then go back down and that's from that + + + align:start position:0% +then go back down and that's from that +we infer that the infant can distinguish + + align:start position:0% +we infer that the infant can distinguish + + + align:start position:0% +we infer that the infant can distinguish +between horses and cows but if it's not + + align:start position:0% +between horses and cows but if it's not + + + align:start position:0% +between horses and cows but if it's not +old enough the looking time will not go + + align:start position:0% +old enough the looking time will not go + + + align:start position:0% +old enough the looking time will not go +up so it as the infant gets older and + + align:start position:0% +up so it as the infant gets older and + + + align:start position:0% +up so it as the infant gets older and +older it can make more and more fine + + align:start position:0% +older it can make more and more fine + + + align:start position:0% +older it can make more and more fine +scale discriminations between categories + + align:start position:0% +scale discriminations between categories + + + align:start position:0% +scale discriminations between categories +it turns out so property verification + + align:start position:0% +it turns out so property verification + + + align:start position:0% +it turns out so property verification +tasks you can ask can a canary move can + + align:start position:0% +tasks you can ask can a canary move can + + + align:start position:0% +tasks you can ask can a canary move can +it sing and certain questions are + + align:start position:0% +it sing and certain questions are + + + align:start position:0% +it sing and certain questions are +answered quickly certain questions are + + align:start position:0% +answered quickly certain questions are + + + align:start position:0% +answered quickly certain questions are +answered late which speaks to certain + + align:start position:0% +answered late which speaks to certain + + + align:start position:0% +answered late which speaks to certain +properties being central and peripheral + + align:start position:0% +properties being central and peripheral + + + align:start position:0% +properties being central and peripheral +to certain categories a category + + align:start position:0% +to certain categories a category + + + align:start position:0% +to certain categories a category +membership queries is a sparrow a bird + + align:start position:0% +membership queries is a sparrow a bird + + + align:start position:0% +membership queries is a sparrow a bird +or as an ostrich bird again there's + + align:start position:0% +or as an ostrich bird again there's + + + align:start position:0% +or as an ostrich bird again there's +different relate latencies and that's + + align:start position:0% +different relate latencies and that's + + + align:start position:0% +different relate latencies and that's +that suggests that there are typical and + + align:start position:0% +that suggests that there are typical and + + + align:start position:0% +that suggests that there are typical and +atypical category members and also very + + align:start position:0% +atypical category members and also very + + + align:start position:0% +atypical category members and also very +very important to us in is inductive + + align:start position:0% +very important to us in is inductive + + + align:start position:0% +very important to us in is inductive +generalization we can both generalize + + align:start position:0% +generalization we can both generalize + + + align:start position:0% +generalization we can both generalize +familiar properties to novel objects for + + align:start position:0% +familiar properties to novel objects for + + + align:start position:0% +familiar properties to novel objects for +example a blick has feathers does it fly + + align:start position:0% +example a blick has feathers does it fly + + + align:start position:0% +example a blick has feathers does it fly +does it sing and we can generalize novel + + align:start position:0% +does it sing and we can generalize novel + + + align:start position:0% +does it sing and we can generalize novel +properties to familiar objects a bird + + align:start position:0% +properties to familiar objects a bird + + + align:start position:0% +properties to familiar objects a bird +has gene X does a crocodile have gene X + + align:start position:0% +has gene X does a crocodile have gene X + + + align:start position:0% +has gene X does a crocodile have gene X +does a dog have gene X you know so the + + align:start position:0% +does a dog have gene X you know so the + + + align:start position:0% +does a dog have gene X you know so the +so people have measured these patterns + + align:start position:0% +so people have measured these patterns + + + align:start position:0% +so people have measured these patterns +of inductive generalizations and there's + + align:start position:0% +of inductive generalizations and there's + + + align:start position:0% +of inductive generalizations and there's +various theories that try to explain all + + align:start position:0% +various theories that try to explain all + + + align:start position:0% +various theories that try to explain all +of this stuff so jay has been working on + + align:start position:0% +of this stuff so jay has been working on + + + align:start position:0% +of this stuff so jay has been working on +this stuff from a neural network + + align:start position:0% +this stuff from a neural network + + + align:start position:0% +this stuff from a neural network +perspective and he wrote a beautiful + + align:start position:0% +perspective and he wrote a beautiful + + + align:start position:0% +perspective and he wrote a beautiful +book called semantic cognition where he + + align:start position:0% +book called semantic cognition where he + + + align:start position:0% +book called semantic cognition where he +uses neural networks to explain a whole + + align:start position:0% +uses neural networks to explain a whole + + + align:start position:0% +uses neural networks to explain a whole +variety of phenomena especially for + + align:start position:0% +variety of phenomena especially for + + + align:start position:0% +variety of phenomena especially for +example the progressive differential of + + align:start position:0% +example the progressive differential of + + + align:start position:0% +example the progressive differential of +progressive differentiation of concepts + + align:start position:0% +progressive differentiation of concepts + + + align:start position:0% +progressive differentiation of concepts +so let me just walk you through that and + + align:start position:0% +so let me just walk you through that and + + + align:start position:0% +so let me just walk you through that and +so this was you know my you know an + + align:start position:0% +so this was you know my you know an + + + align:start position:0% +so this was you know my you know an +encounter with a you know at first + + align:start position:0% +encounter with a you know at first + + + align:start position:0% +encounter with a you know at first +encounter with a deep neural network so + + align:start position:0% +encounter with a deep neural network so + + + align:start position:0% +encounter with a deep neural network so +they were they were doing deep neural + + align:start position:0% +they were they were doing deep neural + + + align:start position:0% +they were they were doing deep neural +networks before they became popular and + + align:start position:0% +networks before they became popular and + + + align:start position:0% +networks before they became popular and +so what they were doing was they asked + + align:start position:0% +so what they were doing was they asked + + + align:start position:0% +so what they were doing was they asked +can we model infants the development of + + align:start position:0% +can we model infants the development of + + + align:start position:0% +can we model infants the development of +say concepts and infants and so what + + align:start position:0% +say concepts and infants and so what + + + align:start position:0% +say concepts and infants and so what +they did was they had a toy data set + + align:start position:0% +they did was they had a toy data set + + + align:start position:0% +they did was they had a toy data set +where they had a bunch of objects and + + align:start position:0% +where they had a bunch of objects and + + + align:start position:0% +where they had a bunch of objects and +each object had a whole bunch of + + align:start position:0% +each object had a whole bunch of + + + align:start position:0% +each object had a whole bunch of +properties so for example a canary can + + align:start position:0% +properties so for example a canary can + + + align:start position:0% +properties so for example a canary can +grow move fly and swing sing right and + + align:start position:0% +grow move fly and swing sing right and + + + align:start position:0% +grow move fly and swing sing right and +and so what they did was they exposed + + align:start position:0% +and so what they did was they exposed + + + align:start position:0% +and so what they did was they exposed +this deep neural network to training + + align:start position:0% +this deep neural network to training + + + align:start position:0% +this deep neural network to training +data of this form you know they had a + + align:start position:0% +data of this form you know they had a + + + align:start position:0% +data of this form you know they had a +whole bunch of features and questions + + align:start position:0% +whole bunch of features and questions + + + align:start position:0% +whole bunch of features and questions +and objects and they just exposed the + + align:start position:0% +and objects and they just exposed the + + + align:start position:0% +and objects and they just exposed the +network to training data trained it + + align:start position:0% +network to training data trained it + + + align:start position:0% +network to training data trained it +using back propagation and they looked + + align:start position:0% +using back propagation and they looked + + + align:start position:0% +using back propagation and they looked +at the internal representations in the + + align:start position:0% +at the internal representations in the + + + align:start position:0% +at the internal representations in the +network especially their evolution over + + align:start position:0% +network especially their evolution over + + + align:start position:0% +network especially their evolution over +developmental time or training time + + align:start position:0% +developmental time or training time + + + align:start position:0% +developmental time or training time +right and this is what they found + + align:start position:0% +right and this is what they found + + + align:start position:0% +right and this is what they found +so initially the network started with + + align:start position:0% +so initially the network started with + + + align:start position:0% +so initially the network started with +random weights so there was no structure + + align:start position:0% +random weights so there was no structure + + + align:start position:0% +random weights so there was no structure +so these are okay so what what did they + + align:start position:0% +so these are okay so what what did they + + + align:start position:0% +so these are okay so what what did they +do here they looked at the the distances + + align:start position:0% +do here they looked at the the distances + + + align:start position:0% +do here they looked at the the distances +between the internal representations in + + align:start position:0% +between the internal representations in + + + align:start position:0% +between the internal representations in +this space and they did har cocoa + + align:start position:0% +this space and they did har cocoa + + + align:start position:0% +this space and they did har cocoa +clustering or multi-dimensional scaling + + align:start position:0% +clustering or multi-dimensional scaling + + + align:start position:0% +clustering or multi-dimensional scaling +and they found these plots or these + + align:start position:0% +and they found these plots or these + + + align:start position:0% +and they found these plots or these +plots right so so what you see is early + + align:start position:0% +plots right so so what you see is early + + + align:start position:0% +plots right so so what you see is early +in developmental time the network first + + align:start position:0% +in developmental time the network first + + + align:start position:0% +in developmental time the network first +makes a coarse grained discrimination + + align:start position:0% +makes a coarse grained discrimination + + + align:start position:0% +makes a coarse grained discrimination +between animals and and plants right and + + align:start position:0% +between animals and and plants right and + + + align:start position:0% +between animals and and plants right and +then and then later it makes finer scale + + align:start position:0% +then and then later it makes finer scale + + + align:start position:0% +then and then later it makes finer scale +discriminations and then eventually when + + align:start position:0% +discriminations and then eventually when + + + align:start position:0% +discriminations and then eventually when +it's fully learned it has it learns the + + align:start position:0% +it's fully learned it has it learns the + + + align:start position:0% +it's fully learned it has it learns the +hierarchical structure that's implicit + + align:start position:0% +hierarchical structure that's implicit + + + align:start position:0% +hierarchical structure that's implicit +in the training data okay and this is + + align:start position:0% +in the training data okay and this is + + + align:start position:0% +in the training data okay and this is +the multi-dimensional scaling plot where + + align:start position:0% +the multi-dimensional scaling plot where + + + align:start position:0% +the multi-dimensional scaling plot where +initially the animals move away from the + + align:start position:0% +initially the animals move away from the + + + align:start position:0% +initially the animals move away from the +plants and then you know fish move away + + align:start position:0% +plants and then you know fish move away + + + align:start position:0% +plants and then you know fish move away +from birds and and trees move away from + + align:start position:0% +from birds and and trees move away from + + + align:start position:0% +from birds and and trees move away from +flowers and then finally individual + + align:start position:0% +flowers and then finally individual + + + align:start position:0% +flowers and then finally individual +discriminations are learned so when I + + align:start position:0% +discriminations are learned so when I + + + align:start position:0% +discriminations are learned so when I +learned about this I was at once excited + + align:start position:0% +learned about this I was at once excited + + + align:start position:0% +learned about this I was at once excited +and mystify and also mystified because + + align:start position:0% +and mystify and also mystified because + + + align:start position:0% +and mystify and also mystified because +this is sort of qualitatively behaving + + align:start position:0% +this is sort of qualitatively behaving + + + align:start position:0% +this is sort of qualitatively behaving +like the way that an infant behaves yet + + align:start position:0% +like the way that an infant behaves yet + + + align:start position:0% +like the way that an infant behaves yet +it's a really stupid neural network with + + align:start position:0% +it's a really stupid neural network with + + + align:start position:0% +it's a really stupid neural network with +like five layers yet I don't understand + + align:start position:0% +like five layers yet I don't understand + + + align:start position:0% +like five layers yet I don't understand +how it's doing this right it so so I + + align:start position:0% +how it's doing this right it so so I + + + align:start position:0% +how it's doing this right it so so I +wanted a theory of what's going on here + + align:start position:0% +wanted a theory of what's going on here + + + align:start position:0% +wanted a theory of what's going on here +right so and by the way you know there's + + align:start position:0% +right so and by the way you know there's + + + align:start position:0% +right so and by the way you know there's +lots of reasons to believe that semantic + + align:start position:0% +lots of reasons to believe that semantic + + + align:start position:0% +lots of reasons to believe that semantic +relations + + align:start position:0% +relations + + + align:start position:0% +relations +are in cloak are encoded in the brain + + align:start position:0% +are in cloak are encoded in the brain + + + align:start position:0% +are in cloak are encoded in the brain +using relatively simple metrics like + + align:start position:0% +using relatively simple metrics like + + + align:start position:0% +using relatively simple metrics like +Euclidean distance between neural + + align:start position:0% +Euclidean distance between neural + + + align:start position:0% +Euclidean distance between neural +representations for different objects so + + align:start position:0% +representations for different objects so + + + align:start position:0% +representations for different objects so +for example this is a famous study which + + align:start position:0% +for example this is a famous study which + + + align:start position:0% +for example this is a famous study which +I'm sure you've seen what they showed + + align:start position:0% +I'm sure you've seen what they showed + + + align:start position:0% +I'm sure you've seen what they showed +was a whole bunch of objects to both + + align:start position:0% +was a whole bunch of objects to both + + + align:start position:0% +was a whole bunch of objects to both +monkeys and humans and they clustered + + align:start position:0% +monkeys and humans and they clustered + + + align:start position:0% +monkeys and humans and they clustered +the objects or looked at similarity + + align:start position:0% +the objects or looked at similarity + + + align:start position:0% +the objects or looked at similarity +matrix of the objects measured using a + + align:start position:0% +matrix of the objects measured using a + + + align:start position:0% +matrix of the objects measured using a +Euclidean distance in neural NIR + + align:start position:0% +Euclidean distance in neural NIR + + + align:start position:0% +Euclidean distance in neural NIR +electrophysiology space of firing rates + + align:start position:0% +electrophysiology space of firing rates + + + align:start position:0% +electrophysiology space of firing rates +of neurons here and voxel activity + + align:start position:0% +of neurons here and voxel activity + + + align:start position:0% +of neurons here and voxel activity +patterns in the human and they showed + + align:start position:0% +patterns in the human and they showed + + + align:start position:0% +patterns in the human and they showed +the same set of objects the monkey and + + align:start position:0% +the same set of objects the monkey and + + + align:start position:0% +the same set of objects the monkey and +human and and the matrices aligned + + align:start position:0% +human and and the matrices aligned + + + align:start position:0% +human and and the matrices aligned +essentially so basically the similarity + + align:start position:0% +essentially so basically the similarity + + + align:start position:0% +essentially so basically the similarity +structure of internal representations as + + align:start position:0% +structure of internal representations as + + + align:start position:0% +structure of internal representations as +both monkey and human is the same so we + + align:start position:0% +both monkey and human is the same so we + + + align:start position:0% +both monkey and human is the same so we +tend to encode similar we tend to encode + + align:start position:0% +tend to encode similar we tend to encode + + + align:start position:0% +tend to encode similar we tend to encode +semantic information using these + + align:start position:0% +semantic information using these + + + align:start position:0% +semantic information using these +similarity representations so this is + + align:start position:0% +similarity representations so this is + + + align:start position:0% +similarity representations so this is +the hierarchical clustering view so this + + align:start position:0% +the hierarchical clustering view so this + + + align:start position:0% +the hierarchical clustering view so this +sort of you know this sort of seems to + + align:start position:0% +sort of you know this sort of seems to + + + align:start position:0% +sort of you know this sort of seems to +actually happen in in real live animals + + align:start position:0% +actually happen in in real live animals + + + align:start position:0% +actually happen in in real live animals +and humans okay there's actually + + align:start position:0% +and humans okay there's actually + + + align:start position:0% +and humans okay there's actually +something else that happens is that + + align:start position:0% +something else that happens is that + + + align:start position:0% +something else that happens is that +different properties are learned on + + align:start position:0% +different properties are learned on + + + align:start position:0% +different properties are learned on +different time scales so for example the + + align:start position:0% +different time scales so for example the + + + align:start position:0% +different time scales so for example the +network can learn that Canaries can move + + align:start position:0% +network can learn that Canaries can move + + + align:start position:0% +network can learn that Canaries can move +much more quickly than it learns that a + + align:start position:0% +much more quickly than it learns that a + + + align:start position:0% +much more quickly than it learns that a +canary is yellow so it learns these sort + + align:start position:0% +canary is yellow so it learns these sort + + + align:start position:0% +canary is yellow so it learns these sort +of so some properties are much easier to + + align:start position:0% +of so some properties are much easier to + + + align:start position:0% +of so some properties are much easier to +learn than others and the properties + + align:start position:0% +learn than others and the properties + + + align:start position:0% +learn than others and the properties +that are easier to learn it for the + + align:start position:0% +that are easier to learn it for the + + + align:start position:0% +that are easier to learn it for the +network are also easier to learn for the + + align:start position:0% +network are also easier to learn for the + + + align:start position:0% +network are also easier to learn for the +infant ok so these are the theoretical + + align:start position:0% +infant ok so these are the theoretical + + + align:start position:0% +infant ok so these are the theoretical +questions we'd like to answer what are + + align:start position:0% +questions we'd like to answer what are + + + align:start position:0% +questions we'd like to answer what are +the mathematical principles underlying + + align:start position:0% +the mathematical principles underlying + + + align:start position:0% +the mathematical principles underlying +the hierarchical self-organization of + + align:start position:0% +the hierarchical self-organization of + + + align:start position:0% +the hierarchical self-organization of +internal representations in the network + + align:start position:0% +internal representations in the network + + + align:start position:0% +internal representations in the network +you know this is a complex system so + + align:start position:0% +you know this is a complex system so + + + align:start position:0% +you know this is a complex system so +what are the relative roles of the + + align:start position:0% +what are the relative roles of the + + + align:start position:0% +what are the relative roles of the +various ingredients it's and there's a + + align:start position:0% +various ingredients it's and there's a + + + align:start position:0% +various ingredients it's and there's a +nonlinear input-output response there's + + align:start position:0% +nonlinear input-output response there's + + + align:start position:0% +nonlinear input-output response there's +a learning rule which is back + + align:start position:0% +a learning rule which is back + + + align:start position:0% +a learning rule which is back +propagation + + align:start position:0% +propagation + + + align:start position:0% +propagation +there's the input statistics is the + + align:start position:0% +there's the input statistics is the + + + align:start position:0% +there's the input statistics is the +network somehow reaching into complex + + align:start position:0% +network somehow reaching into complex + + + align:start position:0% +network somehow reaching into complex +input statistics in the in the training + + align:start position:0% +input statistics in the in the training + + + align:start position:0% +input statistics in the in the training +set or or can it really rely on just + + align:start position:0% +set or or can it really rely on just + + + align:start position:0% +set or or can it really rely on just +second-order statistics you know there + + align:start position:0% +second-order statistics you know there + + + align:start position:0% +second-order statistics you know there +what is a mathematical definition of + + align:start position:0% +what is a mathematical definition of + + + align:start position:0% +what is a mathematical definition of +something called category currents and + + align:start position:0% +something called category currents and + + + align:start position:0% +something called category currents and +how does it relate to the speed of + + align:start position:0% +how does it relate to the speed of + + + align:start position:0% +how does it relate to the speed of +category learning so what determines the + + align:start position:0% +category learning so what determines the + + + align:start position:0% +category learning so what determines the +speed at which we learn categories why + + align:start position:0% +speed at which we learn categories why + + + align:start position:0% +speed at which we learn categories why +are some properties learn more quickly + + align:start position:0% +are some properties learn more quickly + + + align:start position:0% +are some properties learn more quickly +than others and how can we explain + + align:start position:0% +than others and how can we explain + + + align:start position:0% +than others and how can we explain +changing patterns of inductive + + align:start position:0% +changing patterns of inductive + + + align:start position:0% +changing patterns of inductive +generalization over these developmental + + align:start position:0% +generalization over these developmental + + + align:start position:0% +generalization over these developmental +timescales so ok so how do we get a + + align:start position:0% +timescales so ok so how do we get a + + + align:start position:0% +timescales so ok so how do we get a +theory well it turns out if you look at + + align:start position:0% +theory well it turns out if you look at + + + align:start position:0% +theory well it turns out if you look at +the activations of this network as its + + align:start position:0% +the activations of this network as its + + + align:start position:0% +the activations of this network as its +training over time so these are sigmoid + + align:start position:0% +training over time so these are sigmoid + + + align:start position:0% +training over time so these are sigmoid +units and that the activations don't + + align:start position:0% +units and that the activations don't + + + align:start position:0% +units and that the activations don't +really hit + + align:start position:0% +really hit + + + align:start position:0% +really hit +the saturating regime that much during + + align:start position:0% +the saturating regime that much during + + + align:start position:0% +the saturating regime that much during +training because you start from small + + align:start position:0% +training because you start from small + + + align:start position:0% +training because you start from small +weights so we started with an audacious + + align:start position:0% +weights so we started with an audacious + + + align:start position:0% +weights so we started with an audacious +proposal that maybe even a linear neural + + align:start position:0% +proposal that maybe even a linear neural + + + align:start position:0% +proposal that maybe even a linear neural +network might exhibit this kind of + + align:start position:0% +network might exhibit this kind of + + + align:start position:0% +network might exhibit this kind of +learning dynamics okay now it's not at + + align:start position:0% +learning dynamics okay now it's not at + + + align:start position:0% +learning dynamics okay now it's not at +all obvious that it should because it's + + align:start position:0% +all obvious that it should because it's + + + align:start position:0% +all obvious that it should because it's +a simple linear neural network and this + + align:start position:0% +a simple linear neural network and this + + + align:start position:0% +a simple linear neural network and this +learning dynamics is highly nonlinear + + align:start position:0% +learning dynamics is highly nonlinear + + + align:start position:0% +learning dynamics is highly nonlinear +all right but it turns out that even in + + align:start position:0% +all right but it turns out that even in + + + align:start position:0% +all right but it turns out that even in +a linear neural network the dynamics of + + align:start position:0% +a linear neural network the dynamics of + + + align:start position:0% +a linear neural network the dynamics of +learning on synaptic weight space is + + align:start position:0% +learning on synaptic weight space is + + + align:start position:0% +learning on synaptic weight space is +nonlinear and so there might be a hope + + align:start position:0% +nonlinear and so there might be a hope + + + align:start position:0% +nonlinear and so there might be a hope +that it might work and we might be able + + align:start position:0% +that it might work and we might be able + + + align:start position:0% +that it might work and we might be able +to get a coherent theory okay so what we + + align:start position:0% +to get a coherent theory okay so what we + + + align:start position:0% +to get a coherent theory okay so what we +did was we analyzed just a simple linear + + align:start position:0% +did was we analyzed just a simple linear + + + align:start position:0% +did was we analyzed just a simple linear +neural network that looks like this that + + align:start position:0% +neural network that looks like this that + + + align:start position:0% +neural network that looks like this that +goes from a input layer to hidden layer + + align:start position:0% +goes from a input layer to hidden layer + + + align:start position:0% +goes from a input layer to hidden layer +to output layer so the composite map is + + align:start position:0% +to output layer so the composite map is + + + align:start position:0% +to output layer so the composite map is +linear okay so so we can write down + + align:start position:0% +linear okay so so we can write down + + + align:start position:0% +linear okay so so we can write down +dynamical equations on weight space for + + align:start position:0% +dynamical equations on weight space for + + + align:start position:0% +dynamical equations on weight space for +the learning dynamics so this is the + + align:start position:0% +the learning dynamics so this is the + + + align:start position:0% +the learning dynamics so this is the +training data and we can adjust the + + align:start position:0% +training data and we can adjust the + + + align:start position:0% +training data and we can adjust the +weights using back propagation and these + + align:start position:0% +weights using back propagation and these + + + align:start position:0% +weights using back propagation and these +are the back propagation equations and + + align:start position:0% +are the back propagation equations and + + + align:start position:0% +are the back propagation equations and +if we work in a limit where the learning + + align:start position:0% +if we work in a limit where the learning + + + align:start position:0% +if we work in a limit where the learning +is slow relative to the time it takes to + + align:start position:0% +is slow relative to the time it takes to + + + align:start position:0% +is slow relative to the time it takes to +cycle through the data set you can take + + align:start position:0% +cycle through the data set you can take + + + align:start position:0% +cycle through the data set you can take +a continuous time limit and you + + align:start position:0% +a continuous time limit and you + + + align:start position:0% +a continuous time limit and you +essentially get a nonlinear set of + + align:start position:0% +essentially get a nonlinear set of + + + align:start position:0% +essentially get a nonlinear set of +equations on weight space right and the + + align:start position:0% +equations on weight space right and the + + + align:start position:0% +equations on weight space right and the +equations are cubic in the weights right + + align:start position:0% +equations are cubic in the weights right + + + align:start position:0% +equations are cubic in the weights right +and that's because the error is quartic + + align:start position:0% +and that's because the error is quartic + + + align:start position:0% +and that's because the error is quartic +in the weights right the error is the + + align:start position:0% +in the weights right the error is the + + + align:start position:0% +in the weights right the error is the +output minus W w times the input squared + + align:start position:0% +output minus W w times the input squared + + + align:start position:0% +output minus W w times the input squared +so the errors quartic in the weights and + + align:start position:0% +so the errors quartic in the weights and + + + align:start position:0% +so the errors quartic in the weights and +so if you differentiate we're supposed + + align:start position:0% +so if you differentiate we're supposed + + + align:start position:0% +so if you differentiate we're supposed +to get the weights on the right hand + + align:start position:0% +to get the weights on the right hand + + + align:start position:0% +to get the weights on the right hand +side the gradient descent equations will + + align:start position:0% +side the gradient descent equations will + + + align:start position:0% +side the gradient descent equations will +be cubic in the weights but there is one + + align:start position:0% +be cubic in the weights but there is one + + + align:start position:0% +be cubic in the weights but there is one +simplification that happens because the + + align:start position:0% +simplification that happens because the + + + align:start position:0% +simplification that happens because the +network is linear it's learning dynamics + + align:start position:0% +network is linear it's learning dynamics + + + align:start position:0% +network is linear it's learning dynamics +is sensitive only to the second-order + + align:start position:0% +is sensitive only to the second-order + + + align:start position:0% +is sensitive only to the second-order +statistics of the data right so in + + align:start position:0% +statistics of the data right so in + + + align:start position:0% +statistics of the data right so in +particular the input input covariance + + align:start position:0% +particular the input input covariance + + + align:start position:0% +particular the input input covariance +matrix and the input-output covariance + + align:start position:0% +matrix and the input-output covariance + + + align:start position:0% +matrix and the input-output covariance +matrix okay + + align:start position:0% +matrix okay + + + align:start position:0% +matrix okay +so essentially this network knows only + + align:start position:0% +so essentially this network knows only + + + align:start position:0% +so essentially this network knows only +about second-order statistics in our + + align:start position:0% +about second-order statistics in our + + + align:start position:0% +about second-order statistics in our +work here that the input statistics is + + align:start position:0% +work here that the input statistics is + + + align:start position:0% +work here that the input statistics is +white so it's really only the + + align:start position:0% +white so it's really only the + + + align:start position:0% +white so it's really only the +input-output statistics the drives + + align:start position:0% +input-output statistics the drives + + + align:start position:0% +input-output statistics the drives +learning okay so this is a set of + + align:start position:0% +learning okay so this is a set of + + + align:start position:0% +learning okay so this is a set of +coupled nonlinear differential equations + + align:start position:0% +coupled nonlinear differential equations + + + align:start position:0% +coupled nonlinear differential equations +they're in general hard to solve but we + + align:start position:0% +they're in general hard to solve but we + + + align:start position:0% +they're in general hard to solve but we +found solutions to them so what we we + + align:start position:0% +found solutions to them so what we we + + + align:start position:0% +found solutions to them so what we we +can express the solutions in terms of + + align:start position:0% +can express the solutions in terms of + + + align:start position:0% +can express the solutions in terms of +the singular value decomposition of the + + align:start position:0% +the singular value decomposition of the + + + align:start position:0% +the singular value decomposition of the +input-output covariance matrix so so any + + align:start position:0% +input-output covariance matrix so so any + + + align:start position:0% +input-output covariance matrix so so any +you know any rectangular matrix has a + + align:start position:0% +you know any rectangular matrix has a + + + align:start position:0% +you know any rectangular matrix has a +unique singular value decomposition in + + align:start position:0% +unique singular value decomposition in + + + align:start position:0% +unique singular value decomposition in +this context we can think about the + + align:start position:0% +this context we can think about the + + + align:start position:0% +this context we can think about the +input-output covariance matrix as a + + align:start position:0% +input-output covariance matrix as a + + + align:start position:0% +input-output covariance matrix as a +matrix that map's input objects to + + align:start position:0% +matrix that map's input objects to + + + align:start position:0% +matrix that map's input objects to +feature attributes and the singular + + align:start position:0% +feature attributes and the singular + + + align:start position:0% +feature attributes and the singular +vectors have an interpretation where the + + align:start position:0% +vectors have an interpretation where the + + + align:start position:0% +vectors have an interpretation where the +the these singular vector is essentially + + align:start position:0% +the these singular vector is essentially + + + align:start position:0% +the these singular vector is essentially +map objects into interim representations + + align:start position:0% +map objects into interim representations + + + align:start position:0% +map objects into interim representations +the singular values amplify them and + + align:start position:0% +the singular values amplify them and + + + align:start position:0% +the singular values amplify them and +then the columns of you are sort of + + align:start position:0% +then the columns of you are sort of + + + align:start position:0% +then the columns of you are sort of +feature synthesizers the columns are + + align:start position:0% +feature synthesizers the columns are + + + align:start position:0% +feature synthesizers the columns are +sort of modes in the output feature + + align:start position:0% +sort of modes in the output feature + + + align:start position:0% +sort of modes in the output feature +space okay so this is the SVD but the + + align:start position:0% +space okay so this is the SVD but the + + + align:start position:0% +space okay so this is the SVD but the +question is how does the learning + + align:start position:0% +question is how does the learning + + + align:start position:0% +question is how does the learning +dynamics how does this drive the + + align:start position:0% +dynamics how does this drive the + + + align:start position:0% +dynamics how does this drive the +learning dynamics so what we did was was + + align:start position:0% +learning dynamics so what we did was was + + + align:start position:0% +learning dynamics so what we did was was +we found exact solutions to the learning + + align:start position:0% +we found exact solutions to the learning + + + align:start position:0% +we found exact solutions to the learning +dynamics of this form where the product + + align:start position:0% +dynamics of this form where the product + + + align:start position:0% +dynamics of this form where the product +of the in the layer 1 to layer 2 weights + + align:start position:0% +of the in the layer 1 to layer 2 weights + + + align:start position:0% +of the in the layer 1 to layer 2 weights +in layer 2 to layer 3 weights are of + + align:start position:0% +in layer 2 to layer 3 weights are of + + + align:start position:0% +in layer 2 to layer 3 weights are of +this form where essentially the system + + align:start position:0% +this form where essentially the system + + + align:start position:0% +this form where essentially the system +what it's doing the composite system is + + align:start position:0% +what it's doing the composite system is + + + align:start position:0% +what it's doing the composite system is +building up the singular value + + align:start position:0% +building up the singular value + + + align:start position:0% +building up the singular value +decomposition of the input-output + + align:start position:0% +decomposition of the input-output + + + align:start position:0% +decomposition of the input-output +covariance matrix mode by mode and each + + align:start position:0% +covariance matrix mode by mode and each + + + align:start position:0% +covariance matrix mode by mode and each +mode alpha associated with singular + + align:start position:0% +mode alpha associated with singular + + + align:start position:0% +mode alpha associated with singular +value alpha in the training data is + + align:start position:0% +value alpha in the training data is + + + align:start position:0% +value alpha in the training data is +being learned in the sigmoid illan ok in + + align:start position:0% +being learned in the sigmoid illan ok in + + + align:start position:0% +being learned in the sigmoid illan ok in +a way that so at x 0 a is sort of small + + align:start position:0% +a way that so at x 0 a is sort of small + + + align:start position:0% +a way that so at x 0 a is sort of small +and random you know some initial + + align:start position:0% +and random you know some initial + + + align:start position:0% +and random you know some initial +condition a 0 but over time as as time + + align:start position:0% +condition a 0 but over time as as time + + + align:start position:0% +condition a 0 but over time as as time +goes to infinity training time goes to + + align:start position:0% +goes to infinity training time goes to + + + align:start position:0% +goes to infinity training time goes to +infinity the the a approaches the actual + + align:start position:0% +infinity the the a approaches the actual + + + align:start position:0% +infinity the the a approaches the actual +singular value in the input-output + + align:start position:0% +singular value in the input-output + + + align:start position:0% +singular value in the input-output +covariance matrix so basically this is + + align:start position:0% +covariance matrix so basically this is + + + align:start position:0% +covariance matrix so basically this is +the learning dynamic so nothing happens + + align:start position:0% +the learning dynamic so nothing happens + + + align:start position:0% +the learning dynamic so nothing happens +for a while and then suddenly the + + align:start position:0% +for a while and then suddenly the + + + align:start position:0% +for a while and then suddenly the +strongest singular mode defined by the + + align:start position:0% +strongest singular mode defined by the + + + align:start position:0% +strongest singular mode defined by the +largest single value gets learned and + + align:start position:0% +largest single value gets learned and + + + align:start position:0% +largest single value gets learned and +then later on smaller singular mode gets + + align:start position:0% +then later on smaller singular mode gets + + + align:start position:0% +then later on smaller singular mode gets +learned and later on a even smaller + + align:start position:0% +learned and later on a even smaller + + + align:start position:0% +learned and later on a even smaller +singular mode gets learned and the time + + align:start position:0% +singular mode gets learned and the time + + + align:start position:0% +singular mode gets learned and the time +it takes to learn each mode is governed + + align:start position:0% +it takes to learn each mode is governed + + + align:start position:0% +it takes to learn each mode is governed +by 1 over the singular value so just + + align:start position:0% +by 1 over the singular value so just + + + align:start position:0% +by 1 over the singular value so just +intuitively stronger statistical + + align:start position:0% +intuitively stronger statistical + + + align:start position:0% +intuitively stronger statistical +structure as quantified by singular + + align:start position:0% +structure as quantified by singular + + + align:start position:0% +structure as quantified by singular +value is learned first okay that's the + + align:start position:0% +value is learned first okay that's the + + + align:start position:0% +value is learned first okay that's the +intuition often time when we train + + align:start position:0% +intuition often time when we train + + + align:start position:0% +intuition often time when we train +neural networks we see sort of these + + align:start position:0% +neural networks we see sort of these + + + align:start position:0% +neural networks we see sort of these +plateaus in performance where the + + align:start position:0% +plateaus in performance where the + + + align:start position:0% +plateaus in performance where the +network does nothing and then suddenly + + align:start position:0% +network does nothing and then suddenly + + + align:start position:0% +network does nothing and then suddenly +drops plateaus and drops and this + + align:start position:0% +drops plateaus and drops and this + + + align:start position:0% +drops plateaus and drops and this +actually shows that you can see very + + align:start position:0% +actually shows that you can see very + + + align:start position:0% +actually shows that you can see very +very sharp transitions in learning and + + align:start position:0% +very sharp transitions in learning and + + + align:start position:0% +very sharp transitions in learning and +you can actually show that the ratio of + + align:start position:0% +you can actually show that the ratio of + + + align:start position:0% +you can actually show that the ratio of +the transition period to the the + + align:start position:0% +the transition period to the the + + + align:start position:0% +the transition period to the the +ignorance period can be arbitrarily + + align:start position:0% +ignorance period can be arbitrarily + + + align:start position:0% +ignorance period can be arbitrarily +small infants also seem to show these + + align:start position:0% +small infants also seem to show these + + + align:start position:0% +small infants also seem to show these +developmental transitions but + + align:start position:0% +developmental transitions but + + + align:start position:0% +developmental transitions but +okay yes so that's so yeah you you can + + align:start position:0% +okay yes so that's so yeah you you can + + + align:start position:0% +okay yes so that's so yeah you you can +have arbitrarily sharp transitions in + + align:start position:0% +have arbitrarily sharp transitions in + + + align:start position:0% +have arbitrarily sharp transitions in +the system okay so the take-home + + align:start position:0% +the system okay so the take-home + + + align:start position:0% +the system okay so the take-home +messages so so far that is the network + + align:start position:0% +messages so so far that is the network + + + align:start position:0% +messages so so far that is the network +learns different modes of covariation + + align:start position:0% +learns different modes of covariation + + + align:start position:0% +learns different modes of covariation +between input and output and timescale + + align:start position:0% +between input and output and timescale + + + align:start position:0% +between input and output and timescale +inversely proportional to the + + align:start position:0% +inversely proportional to the + + + align:start position:0% +inversely proportional to the +statistical strength of that covariation + + align:start position:0% +statistical strength of that covariation + + + align:start position:0% +statistical strength of that covariation +and you can get these sudden transitions + + align:start position:0% +and you can get these sudden transitions + + + align:start position:0% +and you can get these sudden transitions +and learning now the question is what + + align:start position:0% +and learning now the question is what + + + align:start position:0% +and learning now the question is what +does this have to do with the + + align:start position:0% +does this have to do with the + + + align:start position:0% +does this have to do with the +hierarchical differentiation of concepts + + align:start position:0% +hierarchical differentiation of concepts + + + align:start position:0% +hierarchical differentiation of concepts +right that's what we'd like to + + align:start position:0% +right that's what we'd like to + + + align:start position:0% +right that's what we'd like to +understand first so now we've come up + + align:start position:0% +understand first so now we've come up + + + align:start position:0% +understand first so now we've come up +with a general theory of learning the + + align:start position:0% +with a general theory of learning the + + + align:start position:0% +with a general theory of learning the +nonlinear dynamics of learning in these + + align:start position:0% +nonlinear dynamics of learning in these + + + align:start position:0% +nonlinear dynamics of learning in these +in these deep circuits now we want to + + align:start position:0% +in these deep circuits now we want to + + + align:start position:0% +in these deep circuits now we want to +connect this back to hierarchical + + align:start position:0% +connect this back to hierarchical + + + align:start position:0% +connect this back to hierarchical +structure so one of the the things with + + align:start position:0% +structure so one of the the things with + + + align:start position:0% +structure so one of the the things with +J's work is they were just working with + + align:start position:0% +J's work is they were just working with + + + align:start position:0% +J's work is they were just working with +toy datasets and we didn't have any + + align:start position:0% +toy datasets and we didn't have any + + + align:start position:0% +toy datasets and we didn't have any +theoretical control over those toy + + align:start position:0% +theoretical control over those toy + + + align:start position:0% +theoretical control over those toy +datasets but we sort of understood + + align:start position:0% +datasets but we sort of understood + + + align:start position:0% +datasets but we sort of understood +implicitly these toy datasets of + + align:start position:0% +implicitly these toy datasets of + + + align:start position:0% +implicitly these toy datasets of +hierarchical structure so we need a + + align:start position:0% +hierarchical structure so we need a + + + align:start position:0% +hierarchical structure so we need a +generative model of data controlled + + align:start position:0% +generative model of data controlled + + + align:start position:0% +generative model of data controlled +mathematically well-defined generative + + align:start position:0% +mathematically well-defined generative + + + align:start position:0% +mathematically well-defined generative +model of data that encodes the notion of + + align:start position:0% +model of data that encodes the notion of + + + align:start position:0% +model of data that encodes the notion of +hierarchy okay so so can we move beyond + + align:start position:0% +hierarchy okay so so can we move beyond + + + align:start position:0% +hierarchy okay so so can we move beyond +specific data sets to general principles + + align:start position:0% +specific data sets to general principles + + + align:start position:0% +specific data sets to general principles +of what happens when a neural network is + + align:start position:0% +of what happens when a neural network is + + + align:start position:0% +of what happens when a neural network is +exposed to hierarchical structure that's + + align:start position:0% +exposed to hierarchical structure that's + + + align:start position:0% +exposed to hierarchical structure that's +what we like to answer so we consider a + + align:start position:0% +what we like to answer so we consider a + + + align:start position:0% +what we like to answer so we consider a +hierarchical generative model and a + + align:start position:0% +hierarchical generative model and a + + + align:start position:0% +hierarchical generative model and a +classic hierarchical generative model is + + align:start position:0% +classic hierarchical generative model is + + + align:start position:0% +classic hierarchical generative model is +is a yeah so essentially what we want to + + align:start position:0% +is a yeah so essentially what we want to + + + align:start position:0% +is a yeah so essentially what we want to +do is we want to connect the world of + + align:start position:0% +do is we want to connect the world of + + + align:start position:0% +do is we want to connect the world of +generative models to the world of neural + + align:start position:0% +generative models to the world of neural + + + align:start position:0% +generative models to the world of neural +networks and that you know that will + + align:start position:0% +networks and that you know that will + + + align:start position:0% +networks and that you know that will +connect the methods in computational + + align:start position:0% +connect the methods in computational + + + align:start position:0% +connect the methods in computational +neuroscience to this course eventually + + align:start position:0% +neuroscience to this course eventually + + + align:start position:0% +neuroscience to this course eventually +right so so so yeah so we have data + + align:start position:0% +right so so so yeah so we have data + + + align:start position:0% +right so so so yeah so we have data +generated by some generative model we + + align:start position:0% +generated by some generative model we + + + align:start position:0% +generated by some generative model we +take that data and we expose it to a + + align:start position:0% +take that data and we expose it to a + + + align:start position:0% +take that data and we expose it to a +neural network and we'd like to + + align:start position:0% +neural network and we'd like to + + + align:start position:0% +neural network and we'd like to +understand how the dynamics of learning + + align:start position:0% +understand how the dynamics of learning + + + align:start position:0% +understand how the dynamics of learning +depends on the parameters of the + + align:start position:0% +depends on the parameters of the + + + align:start position:0% +depends on the parameters of the +generative model okay so a natural + + align:start position:0% +generative model okay so a natural + + + align:start position:0% +generative model okay so a natural +generative model for defining + + align:start position:0% +generative model for defining + + + align:start position:0% +generative model for defining +hierarchical structure is a branching + + align:start position:0% +hierarchical structure is a branching + + + align:start position:0% +hierarchical structure is a branching +diffusion process that essentially makes + + align:start position:0% +diffusion process that essentially makes + + + align:start position:0% +diffusion process that essentially makes +the process of evolution where + + align:start position:0% +the process of evolution where + + + align:start position:0% +the process of evolution where +properties diffuse down a tree and + + align:start position:0% +properties diffuse down a tree and + + + align:start position:0% +properties diffuse down a tree and +instantiate themselves across a set of + + align:start position:0% +instantiate themselves across a set of + + + align:start position:0% +instantiate themselves across a set of +items so what do I mean by that okay + + align:start position:0% +items so what do I mean by that okay + + + align:start position:0% +items so what do I mean by that okay +okay so so so basically imagine for + + align:start position:0% +okay so so so basically imagine for + + + align:start position:0% +okay so so so basically imagine for +example that your items are at the + + align:start position:0% +example that your items are at the + + + align:start position:0% +example that your items are at the +leaves of a tree right and you can + + align:start position:0% +leaves of a tree right and you can + + + align:start position:0% +leaves of a tree right and you can +imagine that this is the process of + + align:start position:0% +imagine that this is the process of + + + align:start position:0% +imagine that this is the process of +evolution where there's some ancestral + + align:start position:0% +evolution where there's some ancestral + + + align:start position:0% +evolution where there's some ancestral +state maybe for one property so we do + + align:start position:0% +state maybe for one property so we do + + + align:start position:0% +state maybe for one property so we do +one property at a time and the + + align:start position:0% +one property at a time and the + + + align:start position:0% +one property at a time and the +properties are independent of each other + + align:start position:0% +properties are independent of each other + + + align:start position:0% +properties are independent of each other +this might be an ancestral state like + + align:start position:0% +this might be an ancestral state like + + + align:start position:0% +this might be an ancestral state like +can move right and then each time it + + align:start position:0% +can move right and then each time it + + + align:start position:0% +can move right and then each time it +that this + + align:start position:0% +that this + + + align:start position:0% +that this +this property diffuses down the tree + + align:start position:0% +this property diffuses down the tree + + + align:start position:0% +this property diffuses down the tree +there's a probability of flipping okay + + align:start position:0% +there's a probability of flipping okay + + + align:start position:0% +there's a probability of flipping okay +so maybe in this lineage which might + + align:start position:0% +so maybe in this lineage which might + + + align:start position:0% +so maybe in this lineage which might +correspond to animals + + align:start position:0% +correspond to animals + + + align:start position:0% +correspond to animals +this doesn't flip right and in these + + align:start position:0% +this doesn't flip right and in these + + + align:start position:0% +this doesn't flip right and in these +lineages corresponding to plants it does + + align:start position:0% +lineages corresponding to plants it does + + + align:start position:0% +lineages corresponding to plants it does +flip so these things cannot move and + + align:start position:0% +flip so these things cannot move and + + + align:start position:0% +flip so these things cannot move and +these things can move and then maybe it + + align:start position:0% +these things can move and then maybe it + + + align:start position:0% +these things can move and then maybe it +doesn't flip so all of these things + + align:start position:0% +doesn't flip so all of these things + + + align:start position:0% +doesn't flip so all of these things +inherit the property of moving so these + + align:start position:0% +inherit the property of moving so these + + + align:start position:0% +inherit the property of moving so these +are the animals and these things cannot + + align:start position:0% +are the animals and these things cannot + + + align:start position:0% +are the animals and these things cannot +move so these are the plants and then we + + align:start position:0% +move so these are the plants and then we + + + align:start position:0% +move so these are the plants and then we +do that for every single property + + align:start position:0% +do that for every single property + + + align:start position:0% +do that for every single property +independently and we generate a set of + + align:start position:0% +independently and we generate a set of + + + align:start position:0% +independently and we generate a set of +feature vectors so that's our generative + + align:start position:0% +feature vectors so that's our generative + + + align:start position:0% +feature vectors so that's our generative +model so what are the statistical + + align:start position:0% +model so what are the statistical + + + align:start position:0% +model so what are the statistical +properties of generative model so + + align:start position:0% +properties of generative model so + + + align:start position:0% +properties of generative model so +essentially because we know that we're + + align:start position:0% +essentially because we know that we're + + + align:start position:0% +essentially because we know that we're +analyzing these deep linear networks and + + align:start position:0% +analyzing these deep linear networks and + + + align:start position:0% +analyzing these deep linear networks and +we know that the learning dynamics of + + align:start position:0% +we know that the learning dynamics of + + + align:start position:0% +we know that the learning dynamics of +such networks is driven only by the + + align:start position:0% +such networks is driven only by the + + + align:start position:0% +such networks is driven only by the +input upper covariance matrix to + + align:start position:0% +input upper covariance matrix to + + + align:start position:0% +input upper covariance matrix to +understand the learning dynamics we just + + align:start position:0% +understand the learning dynamics we just + + + align:start position:0% +understand the learning dynamics we just +have to compute the singular values and + + align:start position:0% +have to compute the singular values and + + + align:start position:0% +have to compute the singular values and +singular vectors of Harken through + + align:start position:0% +singular vectors of Harken through + + + align:start position:0% +singular vectors of Harken through +structured data generated in this + + align:start position:0% +structured data generated in this + + + align:start position:0% +structured data generated in this +fashion and it's actually quite easy and + + align:start position:0% +fashion and it's actually quite easy and + + + align:start position:0% +fashion and it's actually quite easy and +we did it so here's what happens so + + align:start position:0% +we did it so here's what happens so + + + align:start position:0% +we did it so here's what happens so +imagine a nice symmetric tree like this + + align:start position:0% +imagine a nice symmetric tree like this + + + align:start position:0% +imagine a nice symmetric tree like this +so these are objects if we look at the + + align:start position:0% +so these are objects if we look at the + + + align:start position:0% +so these are objects if we look at the +similarity structure of objects measured + + align:start position:0% +similarity structure of objects measured + + + align:start position:0% +similarity structure of objects measured +by dot product in the feature space + + align:start position:0% +by dot product in the feature space + + + align:start position:0% +by dot product in the feature space +generated by the features under this + + align:start position:0% +generated by the features under this + + + align:start position:0% +generated by the features under this +branching diffusion process we get this + + align:start position:0% +branching diffusion process we get this + + + align:start position:0% +branching diffusion process we get this +nice blocks within block similarity + + align:start position:0% +nice blocks within block similarity + + + align:start position:0% +nice blocks within block similarity +structure where all the items on this on + + align:start position:0% +structure where all the items on this on + + + align:start position:0% +structure where all the items on this on +this branch are you know this item this + + align:start position:0% +this branch are you know this item this + + + align:start position:0% +this branch are you know this item this +item are slightly similar this item this + + align:start position:0% +item are slightly similar this item this + + + align:start position:0% +item are slightly similar this item this +item are even more similar and of course + + align:start position:0% +item are even more similar and of course + + + align:start position:0% +item are even more similar and of course +each item is most similar to itself so + + align:start position:0% +each item is most similar to itself so + + + align:start position:0% +each item is most similar to itself so +you have this hierarchical hierarchy of + + align:start position:0% +you have this hierarchical hierarchy of + + + align:start position:0% +you have this hierarchical hierarchy of +clusters that naturally arise because of + + align:start position:0% +clusters that naturally arise because of + + + align:start position:0% +clusters that naturally arise because of +this branching diffusion process so what + + align:start position:0% +this branching diffusion process so what + + + align:start position:0% +this branching diffusion process so what +are the singular values and singular + + align:start position:0% +are the singular values and singular + + + align:start position:0% +are the singular values and singular +vectors of the of the associated + + align:start position:0% +vectors of the of the associated + + + align:start position:0% +vectors of the of the associated +input-output covariance matrix + + align:start position:0% +input-output covariance matrix + + + align:start position:0% +input-output covariance matrix +well they turn out these are the one set + + align:start position:0% +well they turn out these are the one set + + + align:start position:0% +well they turn out these are the one set +of singular vectors the so called object + + align:start position:0% +of singular vectors the so called object + + + align:start position:0% +of singular vectors the so called object +analyzers which are functions across + + align:start position:0% +analyzers which are functions across + + + align:start position:0% +analyzers which are functions across +objects there's another set of singular + + align:start position:0% +objects there's another set of singular + + + align:start position:0% +objects there's another set of singular +vectors that are functions across + + align:start position:0% +vectors that are functions across + + + align:start position:0% +vectors that are functions across +features which I'm not showing you but + + align:start position:0% +features which I'm not showing you but + + + align:start position:0% +features which I'm not showing you but +we can under but but there's of course + + align:start position:0% +we can under but but there's of course + + + align:start position:0% +we can under but but there's of course +the duality right so that you get pairs + + align:start position:0% +the duality right so that you get pairs + + + align:start position:0% +the duality right so that you get pairs +of singular vectors for each singular + + align:start position:0% +of singular vectors for each singular + + + align:start position:0% +of singular vectors for each singular +value okay so what's the singular vector + + align:start position:0% +value okay so what's the singular vector + + + align:start position:0% +value okay so what's the singular vector +associate or the largest singular value + + align:start position:0% +associate or the largest singular value + + + align:start position:0% +associate or the largest singular value +well it's a uniform mode that's constant + + align:start position:0% +well it's a uniform mode that's constant + + + align:start position:0% +well it's a uniform mode that's constant +across all the objects but the next the + + align:start position:0% +across all the objects but the next the + + + align:start position:0% +across all the objects but the next the +most interesting one the next largest + + align:start position:0% +most interesting one the next largest + + + align:start position:0% +most interesting one the next largest +one is the most lowest frequency + + align:start position:0% +one is the most lowest frequency + + + align:start position:0% +one is the most lowest frequency +function essentially it's constant along + + align:start position:0% +function essentially it's constant along + + + align:start position:0% +function essentially it's constant along +all the ancestors of this branch and a + + align:start position:0% +all the ancestors of this branch and a + + + align:start position:0% +all the ancestors of this branch and a +different constant along all the + + align:start position:0% +different constant along all the + + + align:start position:0% +different constant along all the +ancestors of this branch so this + + align:start position:0% +ancestors of this branch so this + + + align:start position:0% +ancestors of this branch so this +singular vector essentially makes the + + align:start position:0% +singular vector essentially makes the + + + align:start position:0% +singular vector essentially makes the +most coarse-grained discrimination in + + align:start position:0% +most coarse-grained discrimination in + + + align:start position:0% +most coarse-grained discrimination in +this heart cookie structure data set the + + align:start position:0% +this heart cookie structure data set the + + + align:start position:0% +this heart cookie structure data set the +next set of seeing + + align:start position:0% +next set of seeing + + + align:start position:0% +next set of seeing +the vectors as a pair of them + + align:start position:0% +the vectors as a pair of them + + + align:start position:0% +the vectors as a pair of them +discriminate between this set of objects + + align:start position:0% +discriminate between this set of objects + + + align:start position:0% +discriminate between this set of objects +in this set of objects and don't know + + align:start position:0% +in this set of objects and don't know + + + align:start position:0% +in this set of objects and don't know +about these ones and the next one + + align:start position:0% +about these ones and the next one + + + align:start position:0% +about these ones and the next one +discriminates between this set of + + align:start position:0% +discriminates between this set of + + + align:start position:0% +discriminates between this set of +objects in this set of objects okay and + + align:start position:0% +objects in this set of objects okay and + + + align:start position:0% +objects in this set of objects okay and +then as you go down to the smaller + + align:start position:0% +then as you go down to the smaller + + + align:start position:0% +then as you go down to the smaller +singular values you get fine scale you + + align:start position:0% +singular values you get fine scale you + + + align:start position:0% +singular values you get fine scale you +get individual object discriminations + + align:start position:0% +get individual object discriminations + + + align:start position:0% +get individual object discriminations +right so this is how the Hart + + align:start position:0% +right so this is how the Hart + + + align:start position:0% +right so this is how the Hart +constructor is reflected in the second + + align:start position:0% +constructor is reflected in the second + + + align:start position:0% +constructor is reflected in the second +order statistics of the data and and + + align:start position:0% +order statistics of the data and and + + + align:start position:0% +order statistics of the data and and +this these are the singular values so + + align:start position:0% +this these are the singular values so + + + align:start position:0% +this these are the singular values so +the this is the theory for the singular + + align:start position:0% +the this is the theory for the singular + + + align:start position:0% +the this is the theory for the singular +values in a tree that has five levels of + + align:start position:0% +values in a tree that has five levels of + + + align:start position:0% +values in a tree that has five levels of +hierarchy and you can see that the + + align:start position:0% +hierarchy and you can see that the + + + align:start position:0% +hierarchy and you can see that the +singular values decay with the hierarchy + + align:start position:0% +singular values decay with the hierarchy + + + align:start position:0% +singular values decay with the hierarchy +level of the singular vectors okay so + + align:start position:0% +level of the singular vectors okay so + + + align:start position:0% +level of the singular vectors okay so +there's a general theory for this in + + align:start position:0% +there's a general theory for this in + + + align:start position:0% +there's a general theory for this in +which singular vectors are associated + + align:start position:0% +which singular vectors are associated + + + align:start position:0% +which singular vectors are associated +with levels of the tree okay so now you + + align:start position:0% +with levels of the tree okay so now you + + + align:start position:0% +with levels of the tree okay so now you +can see the end of the end of the story + + align:start position:0% +can see the end of the end of the story + + + align:start position:0% +can see the end of the end of the story +if you put the two together you + + align:start position:0% +if you put the two together you + + + align:start position:0% +if you put the two together you +automatically get the results that we + + align:start position:0% +automatically get the results that we + + + align:start position:0% +automatically get the results that we +that we were trying to explain right so + + align:start position:0% +that we were trying to explain right so + + + align:start position:0% +that we were trying to explain right so +essentially the general theory of + + align:start position:0% +essentially the general theory of + + + align:start position:0% +essentially the general theory of +learning says that the network learns + + align:start position:0% +learning says that the network learns + + + align:start position:0% +learning says that the network learns +input-output modes in a time scale given + + align:start position:0% +input-output modes in a time scale given + + + align:start position:0% +input-output modes in a time scale given +by 1 over C 1 over the singular value + + align:start position:0% +by 1 over C 1 over the singular value + + + align:start position:0% +by 1 over C 1 over the singular value +when the data is hierarchically + + align:start position:0% +when the data is hierarchically + + + align:start position:0% +when the data is hierarchically +structured singular values of broader + + align:start position:0% +structured singular values of broader + + + align:start position:0% +structured singular values of broader +hierarchical distinctions are larger + + align:start position:0% +hierarchical distinctions are larger + + + align:start position:0% +hierarchical distinctions are larger +than singular values of finer + + align:start position:0% +than singular values of finer + + + align:start position:0% +than singular values of finer +distinctions and the input-output modes + + align:start position:0% +distinctions and the input-output modes + + + align:start position:0% +distinctions and the input-output modes +correspond exactly to heart conditions + + align:start position:0% +correspond exactly to heart conditions + + + align:start position:0% +correspond exactly to heart conditions +in the tree so that essentially says the + + align:start position:0% +in the tree so that essentially says the + + + align:start position:0% +in the tree so that essentially says the +network must learn broad scale + + align:start position:0% +network must learn broad scale + + + align:start position:0% +network must learn broad scale +discriminations before it can learn fine + + align:start position:0% +discriminations before it can learn fine + + + align:start position:0% +discriminations before it can learn fine +scale discriminations so then actually + + align:start position:0% +scale discriminations so then actually + + + align:start position:0% +scale discriminations so then actually +what we did was we just analytically + + align:start position:0% +what we did was we just analytically + + + align:start position:0% +what we did was we just analytically +worked out that the dynamics of learning + + align:start position:0% +worked out that the dynamics of learning + + + align:start position:0% +worked out that the dynamics of learning +for hard Kuki structured data and we + + align:start position:0% +for hard Kuki structured data and we + + + align:start position:0% +for hard Kuki structured data and we +computed the multi-dimensional scaling + + align:start position:0% +computed the multi-dimensional scaling + + + align:start position:0% +computed the multi-dimensional scaling +and this was theory we never did a + + align:start position:0% +and this was theory we never did a + + + align:start position:0% +and this was theory we never did a +single simulation to get this plot we + + align:start position:0% +single simulation to get this plot we + + + align:start position:0% +single simulation to get this plot we +generated we generated a branching + + align:start position:0% +generated we generated a branching + + + align:start position:0% +generated we generated a branching +diffusion process with it was + + align:start position:0% +diffusion process with it was + + + align:start position:0% +diffusion process with it was +essentially this one and we just labeled + + align:start position:0% +essentially this one and we just labeled + + + align:start position:0% +essentially this one and we just labeled +these nodes arbitrarily with these + + align:start position:0% +these nodes arbitrarily with these + + + align:start position:0% +these nodes arbitrarily with these +labels and this is what we get right so + + align:start position:0% +labels and this is what we get right so + + + align:start position:0% +labels and this is what we get right so +we see the multi-dimensional scaling + + align:start position:0% +we see the multi-dimensional scaling + + + align:start position:0% +we see the multi-dimensional scaling +plot that we sort of see here and + + align:start position:0% +plot that we sort of see here and + + + align:start position:0% +plot that we sort of see here and +essentially just to compare this is what + + align:start position:0% +essentially just to compare this is what + + + align:start position:0% +essentially just to compare this is what +was done with a toy dataset over which + + align:start position:0% +was done with a toy dataset over which + + + align:start position:0% +was done with a toy dataset over which +had no theoretical control in a + + align:start position:0% +had no theoretical control in a + + + align:start position:0% +had no theoretical control in a +nonlinear neural network over which we + + align:start position:0% +nonlinear neural network over which we + + + align:start position:0% +nonlinear neural network over which we +had no theoretical control and this is a + + align:start position:0% +had no theoretical control and this is a + + + align:start position:0% +had no theoretical control and this is a +well-defined mathematical generative + + align:start position:0% +well-defined mathematical generative + + + align:start position:0% +well-defined mathematical generative +model under linear neural network and we + + align:start position:0% +model under linear neural network and we + + + align:start position:0% +model under linear neural network and we +see that we qualitatively explain the + + align:start position:0% +see that we qualitatively explain the + + + align:start position:0% +see that we qualitatively explain the +results so this is the difference + + align:start position:0% +results so this is the difference + + + align:start position:0% +results so this is the difference +between simulation and theory right now + + align:start position:0% +between simulation and theory right now + + + align:start position:0% +between simulation and theory right now +we have a conceptual understanding of + + align:start position:0% +we have a conceptual understanding of + + + align:start position:0% +we have a conceptual understanding of +effectively what was going on in the + + align:start position:0% +effectively what was going on in the + + + align:start position:0% +effectively what was going on in the +circuit and we really a sort of now it's + + align:start position:0% +circuit and we really a sort of now it's + + + align:start position:0% +circuit and we really a sort of now it's +no longer a mystery so now I think I + + align:start position:0% +no longer a mystery so now I think I + + + align:start position:0% +no longer a mystery so now I think I +understand what Jay was doing Jay and + + align:start position:0% +understand what Jay was doing Jay and + + + align:start position:0% +understand what Jay was doing Jay and +collaborators were doing + + align:start position:0% +collaborators were doing + + + align:start position:0% +collaborators were doing +it would be lovely if for all of the + + align:start position:0% +it would be lovely if for all of the + + + align:start position:0% +it would be lovely if for all of the +stuff that's going on in this course we + + align:start position:0% +stuff that's going on in this course we + + + align:start position:0% +stuff that's going on in this course we +could obtain such a deep rigorous + + align:start position:0% +could obtain such a deep rigorous + + + align:start position:0% +could obtain such a deep rigorous +understanding it's much more challenging + + align:start position:0% +understanding it's much more challenging + + + align:start position:0% +understanding it's much more challenging +but it's a goal worthy of pursuit I + + align:start position:0% +but it's a goal worthy of pursuit I + + + align:start position:0% +but it's a goal worthy of pursuit I +think ok so conclusions progressive + + align:start position:0% +think ok so conclusions progressive + + + align:start position:0% +think ok so conclusions progressive +differentiation of hierarchical + + align:start position:0% +differentiation of hierarchical + + + align:start position:0% +differentiation of hierarchical +structure is a general feature of + + align:start position:0% +structure is a general feature of + + + align:start position:0% +structure is a general feature of +learning and deep neural networks it + + align:start position:0% +learning and deep neural networks it + + + align:start position:0% +learning and deep neural networks it +cannot be any other way + + align:start position:0% +cannot be any other way + + + align:start position:0% +cannot be any other way +ok interestingly enough deep but not + + align:start position:0% +ok interestingly enough deep but not + + + align:start position:0% +ok interestingly enough deep but not +shallow networks exhibit such stage like + + align:start position:0% +shallow networks exhibit such stage like + + + align:start position:0% +shallow networks exhibit such stage like +transitions during learning so if you + + align:start position:0% +transitions during learning so if you + + + align:start position:0% +transitions during learning so if you +just do no hidden layers you don't get + + align:start position:0% +just do no hidden layers you don't get + + + align:start position:0% +just do no hidden layers you don't get +this actually you need it in and layer + + align:start position:0% +this actually you need it in and layer + + + align:start position:0% +this actually you need it in and layer +to do this and somewhat surprisingly it + + align:start position:0% +to do this and somewhat surprisingly it + + + align:start position:0% +to do this and somewhat surprisingly it +turns out that even only the second + + align:start position:0% +turns out that even only the second + + + align:start position:0% +turns out that even only the second +order statistics of semantic properties + + align:start position:0% +order statistics of semantic properties + + + align:start position:0% +order statistics of semantic properties +provide powerful statistical signals + + align:start position:0% +provide powerful statistical signals + + + align:start position:0% +provide powerful statistical signals +that are sufficient to drive this + + align:start position:0% +that are sufficient to drive this + + + align:start position:0% +that are sufficient to drive this +nonlinear learning dynamics right you + + align:start position:0% +nonlinear learning dynamics right you + + + align:start position:0% +nonlinear learning dynamics right you +don't need to look at the higher order + + align:start position:0% +don't need to look at the higher order + + + align:start position:0% +don't need to look at the higher order +statistics of the data to get this + + align:start position:0% +statistics of the data to get this + + + align:start position:0% +statistics of the data to get this +dynamic second order sisters sick + + align:start position:0% +dynamic second order sisters sick + + + align:start position:0% +dynamic second order sisters sick +suffice which was not obvious before we + + align:start position:0% +suffice which was not obvious before we + + + align:start position:0% +suffice which was not obvious before we +started okay so in ongoing work we can + + align:start position:0% +started okay so in ongoing work we can + + + align:start position:0% +started okay so in ongoing work we can +explain a whole bunch of things like + + align:start position:0% +explain a whole bunch of things like + + + align:start position:0% +explain a whole bunch of things like +illusory correlations early in learning + + align:start position:0% +illusory correlations early in learning + + + align:start position:0% +illusory correlations early in learning +so for example infants will initially + + align:start position:0% +so for example infants will initially + + + align:start position:0% +so for example infants will initially +say that they don't even know that for + + align:start position:0% +say that they don't even know that for + + + align:start position:0% +say that they don't even know that for +example pine trees don't don't have + + align:start position:0% +example pine trees don't don't have + + + align:start position:0% +example pine trees don't don't have +leaves then at an intermediate point + + align:start position:0% +leaves then at an intermediate point + + + align:start position:0% +leaves then at an intermediate point +they think that pine trees have leaves + + align:start position:0% +they think that pine trees have leaves + + + align:start position:0% +they think that pine trees have leaves +and then at a later point they correctly + + align:start position:0% +and then at a later point they correctly + + + align:start position:0% +and then at a later point they correctly +know that pine trees don't have leaves + + align:start position:0% +know that pine trees don't have leaves + + + align:start position:0% +know that pine trees don't have leaves +right so we can explain these non + + align:start position:0% +right so we can explain these non + + + align:start position:0% +right so we can explain these non +monotonic learning curves we can explain + + align:start position:0% +monotonic learning curves we can explain + + + align:start position:0% +monotonic learning curves we can explain +these familiar in typicality effects we + + align:start position:0% +these familiar in typicality effects we + + + align:start position:0% +these familiar in typicality effects we +can explain an inductive property + + align:start position:0% +can explain an inductive property + + + align:start position:0% +can explain an inductive property +judgments analytically we're looking at + + align:start position:0% +judgments analytically we're looking at + + + align:start position:0% +judgments analytically we're looking at +basic level effects we have a theory of + + align:start position:0% +basic level effects we have a theory of + + + align:start position:0% +basic level effects we have a theory of +category coherence and so on but in the + + align:start position:0% +category coherence and so on but in the + + + align:start position:0% +category coherence and so on but in the +interest of moving forward I wanted to + + align:start position:0% +interest of moving forward I wanted to + + + align:start position:0% +interest of moving forward I wanted to +give short shrift to this stuff so we + + align:start position:0% +give short shrift to this stuff so we + + + align:start position:0% +give short shrift to this stuff so we +essentially we can answer why are some + + align:start position:0% +essentially we can answer why are some + + + align:start position:0% +essentially we can answer why are some +properties learned faster basically + + align:start position:0% +properties learned faster basically + + + align:start position:0% +properties learned faster basically +properties that look that are low + + align:start position:0% +properties that look that are low + + + align:start position:0% +properties that look that are low +frequency properties on the leaves of + + align:start position:0% +frequency properties on the leaves of + + + align:start position:0% +frequency properties on the leaves of +the tree get learned faster properties + + align:start position:0% +the tree get learned faster properties + + + align:start position:0% +the tree get learned faster properties +whose inner product with sync with the + + align:start position:0% +whose inner product with sync with the + + + align:start position:0% +whose inner product with sync with the +singular vectors of largest singular + + align:start position:0% +singular vectors of largest singular + + + align:start position:0% +singular vectors of largest singular +value get learned faster that's the + + align:start position:0% +value get learned faster that's the + + + align:start position:0% +value get learned faster that's the +story why are some items more typical we + + align:start position:0% +story why are some items more typical we + + + align:start position:0% +story why are some items more typical we +have a theory for that how is inductive + + align:start position:0% +have a theory for that how is inductive + + + align:start position:0% +have a theory for that how is inductive +generalization achieved by neural + + align:start position:0% +generalization achieved by neural + + + align:start position:0% +generalization achieved by neural +networks we have a theory for that and + + align:start position:0% +networks we have a theory for that and + + + align:start position:0% +networks we have a theory for that and +so on and you know what is a useful + + align:start position:0% +so on and you know what is a useful + + + align:start position:0% +so on and you know what is a useful +mathematical definition of category hair + + align:start position:0% +mathematical definition of category hair + + + align:start position:0% +mathematical definition of category hair +and so for example you know there + + align:start position:0% +and so for example you know there + + + align:start position:0% +and so for example you know there +some things that are just intuitively + + align:start position:0% +some things that are just intuitively + + + align:start position:0% +some things that are just intuitively +called incoherent categories the set of + + align:start position:0% +called incoherent categories the set of + + + align:start position:0% +called incoherent categories the set of +all things are blue is a very incoherent + + align:start position:0% +all things are blue is a very incoherent + + + align:start position:0% +all things are blue is a very incoherent +category in fact it's so incoherent we + + align:start position:0% +category in fact it's so incoherent we + + + align:start position:0% +category in fact it's so incoherent we +don't have a name for such a category + + align:start position:0% +don't have a name for such a category + + + align:start position:0% +don't have a name for such a category +the set of all things that are dogs + + align:start position:0% +the set of all things that are dogs + + + align:start position:0% +the set of all things that are dogs +seems to be a very coherent category and + + align:start position:0% +seems to be a very coherent category and + + + align:start position:0% +seems to be a very coherent category and +so coherent that we have a you know + + align:start position:0% +so coherent that we have a you know + + + align:start position:0% +so coherent that we have a you know +well-known name for it names quite short + + align:start position:0% +well-known name for it names quite short + + + align:start position:0% +well-known name for it names quite short +actually to actually know I wonder if + + align:start position:0% +actually to actually know I wonder if + + + align:start position:0% +actually to actually know I wonder if +there's a theory where shorter words + + align:start position:0% +there's a theory where shorter words + + + align:start position:0% +there's a theory where shorter words +correspond to more coherent categories + + align:start position:0% +correspond to more coherent categories + + + align:start position:0% +correspond to more coherent categories +and that's like a an informative or + + align:start position:0% +and that's like a an informative or + + + align:start position:0% +and that's like a an informative or +efficient representation of category + + align:start position:0% +efficient representation of category + + + align:start position:0% +efficient representation of category +structure of anyways so we have a + + align:start position:0% +structure of anyways so we have a + + + align:start position:0% +structure of anyways so we have a +natural definition of coherent category + + align:start position:0% +natural definition of coherent category + + + align:start position:0% +natural definition of coherent category +that's precise enough to prove a theorem + + align:start position:0% +that's precise enough to prove a theorem + + + align:start position:0% +that's precise enough to prove a theorem +that coherent categories are learned + + align:start position:0% +that coherent categories are learned + + + align:start position:0% +that coherent categories are learned +faster and actually this this also + + align:start position:0% +faster and actually this this also + + + align:start position:0% +faster and actually this this also +relates the size of the categories so + + align:start position:0% +relates the size of the categories so + + + align:start position:0% +relates the size of the categories so +frequency effects show up anyway so + + align:start position:0% +frequency effects show up anyway so + + + align:start position:0% +frequency effects show up anyway so +there's a lot of stuff there but that + + align:start position:0% +there's a lot of stuff there but that + + + align:start position:0% +there's a lot of stuff there but that +was sort of the entry point so now what + + align:start position:0% +was sort of the entry point so now what + + + align:start position:0% +was sort of the entry point so now what +about a theory of learning in much + + align:start position:0% +about a theory of learning in much + + + align:start position:0% +about a theory of learning in much +deeper networks that have many many + + align:start position:0% +deeper networks that have many many + + + align:start position:0% +deeper networks that have many many +layers okay so again I'm gonna make a + + align:start position:0% +layers okay so again I'm gonna make a + + + align:start position:0% +layers okay so again I'm gonna make a +long story short because it's all + + align:start position:0% +long story short because it's all + + + align:start position:0% +long story short because it's all +published you can read all the details + + align:start position:0% +published you can read all the details + + + align:start position:0% +published you can read all the details +but I wanted to give you the the spirit + + align:start position:0% +but I wanted to give you the the spirit + + + align:start position:0% +but I wanted to give you the the spirit +or the essence of the intuition behind + + align:start position:0% +or the essence of the intuition behind + + + align:start position:0% +or the essence of the intuition behind +the work okay so the questions we like + + align:start position:0% +the work okay so the questions we like + + + align:start position:0% +the work okay so the questions we like +to answer are how does training time + + align:start position:0% +to answer are how does training time + + + align:start position:0% +to answer are how does training time +scale with depth how should learning + + align:start position:0% +scale with depth how should learning + + + align:start position:0% +scale with depth how should learning +rate scale with depth how do different + + align:start position:0% +rate scale with depth how do different + + + align:start position:0% +rate scale with depth how do different +weight initialization impact learning + + align:start position:0% +weight initialization impact learning + + + align:start position:0% +weight initialization impact learning +speed and what we'll do is once we + + align:start position:0% +speed and what we'll do is once we + + + align:start position:0% +speed and what we'll do is once we +understand these theoretically we'll + + align:start position:0% +understand these theoretically we'll + + + align:start position:0% +understand these theoretically we'll +find certain weighed initializations + + align:start position:0% +find certain weighed initializations + + + align:start position:0% +find certain weighed initializations +that correspond to critical dynamics + + align:start position:0% +that correspond to critical dynamics + + + align:start position:0% +that correspond to critical dynamics +which I'll define can aid deep learning + + align:start position:0% +which I'll define can aid deep learning + + + align:start position:0% +which I'll define can aid deep learning +and generalization so the basic idea is + + align:start position:0% +and generalization so the basic idea is + + + align:start position:0% +and generalization so the basic idea is +in a very very deep neural network right + + align:start position:0% +in a very very deep neural network right + + + align:start position:0% +in a very very deep neural network right +you have a you you have a vanishing + + align:start position:0% +you have a you you have a vanishing + + + align:start position:0% +you have a you you have a vanishing +exploding or gradient problem and that's + + align:start position:0% +exploding or gradient problem and that's + + + align:start position:0% +exploding or gradient problem and that's +one of the issues that makes deep neural + + align:start position:0% +one of the issues that makes deep neural + + + align:start position:0% +one of the issues that makes deep neural +network learning hard so if you're going + + align:start position:0% +network learning hard so if you're going + + + align:start position:0% +network learning hard so if you're going +to back propagate the error through + + align:start position:0% +to back propagate the error through + + + align:start position:0% +to back propagate the error through +multiple layers the back propagation + + align:start position:0% +multiple layers the back propagation + + + align:start position:0% +multiple layers the back propagation +operation is a product of jacobians from + + align:start position:0% +operation is a product of jacobians from + + + align:start position:0% +operation is a product of jacobians from +layer to layer and that product of + + align:start position:0% +layer to layer and that product of + + + align:start position:0% +layer to layer and that product of +jacobians is fundamentally of linear + + align:start position:0% +jacobians is fundamentally of linear + + + align:start position:0% +jacobians is fundamentally of linear +mapping right so if the singular value + + align:start position:0% +mapping right so if the singular value + + + align:start position:0% +mapping right so if the singular value +is associated with that linear mapping + + align:start position:0% +is associated with that linear mapping + + + align:start position:0% +is associated with that linear mapping +so essentially if the singular values of + + align:start position:0% +so essentially if the singular values of + + + align:start position:0% +so essentially if the singular values of +the Jacobian and each layer are large + + align:start position:0% +the Jacobian and each layer are large + + + align:start position:0% +the Jacobian and each layer are large +bigger than 1 the product of such + + align:start position:0% +bigger than 1 the product of such + + + align:start position:0% +bigger than 1 the product of such +matrices will lead to a product matrix + + align:start position:0% +matrices will lead to a product matrix + + + align:start position:0% +matrices will lead to a product matrix +that has singular values that grow + + align:start position:0% +that has singular values that grow + + + align:start position:0% +that has singular values that grow +exponentially with depth similarly if + + align:start position:0% +exponentially with depth similarly if + + + align:start position:0% +exponentially with depth similarly if +the singular values are less than 1 + + align:start position:0% +the singular values are less than 1 + + + align:start position:0% +the singular values are less than 1 +they'll decay with depth right so that's + + align:start position:0% +they'll decay with depth right so that's + + + align:start position:0% +they'll decay with depth right so that's +that's a vanishing gradient in the + + align:start position:0% +that's a vanishing gradient in the + + + align:start position:0% +that's a vanishing gradient in the +latter case and an exploding gradient in + + align:start position:0% +latter case and an exploding gradient in + + + align:start position:0% +latter case and an exploding gradient in +the former case that seems to be one of + + align:start position:0% +the former case that seems to be one of + + + align:start position:0% +the former case that seems to be one of +the major impediments + + align:start position:0% +the major impediments + + + align:start position:0% +the major impediments +understanding deep learning so what + + align:start position:0% +understanding deep learning so what + + + align:start position:0% +understanding deep learning so what +people often did was they tried to scale + + align:start position:0% +people often did was they tried to scale + + + align:start position:0% +people often did was they tried to scale +the matrices to avoid this question + + align:start position:0% +the matrices to avoid this question + + + align:start position:0% +the matrices to avoid this question +right so what they often do is they they + + align:start position:0% +right so what they often do is they they + + + align:start position:0% +right so what they often do is they they +picked they initialize the weights + + align:start position:0% +picked they initialize the weights + + + align:start position:0% +picked they initialize the weights +randomly so that W is a random matrix + + align:start position:0% +randomly so that W is a random matrix + + + align:start position:0% +randomly so that W is a random matrix +where the elements W IJ are iid and + + align:start position:0% +where the elements W IJ are iid and + + + align:start position:0% +where the elements W IJ are iid and +Gaussian with a scale factor scaled + + align:start position:0% +Gaussian with a scale factor scaled + + + align:start position:0% +Gaussian with a scale factor scaled +precisely so that the largest eigen + + align:start position:0% +precisely so that the largest eigen + + + align:start position:0% +precisely so that the largest eigen +value of the Jacobian or the + + align:start position:0% +value of the Jacobian or the + + + align:start position:0% +value of the Jacobian or the +backpropagation operator is one okay so + + align:start position:0% +backpropagation operator is one okay so + + + align:start position:0% +backpropagation operator is one okay so +it's like scaling the system so that if + + align:start position:0% +it's like scaling the system so that if + + + align:start position:0% +it's like scaling the system so that if +you place a random error vector here + + align:start position:0% +you place a random error vector here + + + align:start position:0% +you place a random error vector here +right the desired output minus the + + align:start position:0% +right the desired output minus the + + + align:start position:0% +right the desired output minus the +actual output and back propagated + + align:start position:0% +actual output and back propagated + + + align:start position:0% +actual output and back propagated +through a random network a random vector + + align:start position:0% +through a random network a random vector + + + align:start position:0% +through a random network a random vector +will preserve a rare vector will + + align:start position:0% +will preserve a rare vector will + + + align:start position:0% +will preserve a rare vector will +preserve its norm as its back propagated + + align:start position:0% +preserve its norm as its back propagated + + + align:start position:0% +preserve its norm as its back propagated +across and so such and this is the + + align:start position:0% +across and so such and this is the + + + align:start position:0% +across and so such and this is the +famous sort of glory and Benjy Oh + + align:start position:0% +famous sort of glory and Benjy Oh + + + align:start position:0% +famous sort of glory and Benjy Oh +initialization and it works pretty well + + align:start position:0% +initialization and it works pretty well + + + align:start position:0% +initialization and it works pretty well +for depth four or five or whatever right + + align:start position:0% +for depth four or five or whatever right + + + align:start position:0% +for depth four or five or whatever right +okay so we would like a theory of that + + align:start position:0% +okay so we would like a theory of that + + + align:start position:0% +okay so we would like a theory of that +for the learning dynamics of that and as + + align:start position:0% +for the learning dynamics of that and as + + + align:start position:0% +for the learning dynamics of that and as +I said there's no hope for a complete + + align:start position:0% +I said there's no hope for a complete + + + align:start position:0% +I said there's no hope for a complete +theory at the moment with arbitrary + + align:start position:0% +theory at the moment with arbitrary + + + align:start position:0% +theory at the moment with arbitrary +nonlinearities okay so what we're going + + align:start position:0% +nonlinearities okay so what we're going + + + align:start position:0% +nonlinearities okay so what we're going +to do is we're to analyze the learning + + align:start position:0% +to do is we're to analyze the learning + + + align:start position:0% +to do is we're to analyze the learning +dynamics just we'll get rid of the + + align:start position:0% +dynamics just we'll get rid of the + + + align:start position:0% +dynamics just we'll get rid of the +nonlinearities right so again it might + + align:start position:0% +nonlinearities right so again it might + + + align:start position:0% +nonlinearities right so again it might +seem like we're throwing the baby out + + align:start position:0% +seem like we're throwing the baby out + + + align:start position:0% +seem like we're throwing the baby out +with the bathwater but we're actually + + align:start position:0% +with the bathwater but we're actually + + + align:start position:0% +with the bathwater but we're actually +going to learn something that helps us + + align:start position:0% +going to learn something that helps us + + + align:start position:0% +going to learn something that helps us +to Train on than your networks okay so + + align:start position:0% +to Train on than your networks okay so + + + align:start position:0% +to Train on than your networks okay so +the basic idea then is that we have a + + align:start position:0% +the basic idea then is that we have a + + + align:start position:0% +the basic idea then is that we have a +network which is linear so why the + + align:start position:0% +network which is linear so why the + + + align:start position:0% +network which is linear so why the +output is a product of waves right so + + align:start position:0% +output is a product of waves right so + + + align:start position:0% +output is a product of waves right so +then the the back propagation okay so so + + align:start position:0% +then the the back propagation okay so so + + + align:start position:0% +then the the back propagation okay so so +then the back propagation is again just + + align:start position:0% +then the back propagation is again just + + + align:start position:0% +then the back propagation is again just +a product of matrices right the gradient + + align:start position:0% +a product of matrices right the gradient + + + align:start position:0% +a product of matrices right the gradient +descent dynamics is long linear and + + align:start position:0% +descent dynamics is long linear and + + + align:start position:0% +descent dynamics is long linear and +coupled and non convex and actually even + + align:start position:0% +coupled and non convex and actually even + + + align:start position:0% +coupled and non convex and actually even +in this linear network you see plateaus + + align:start position:0% +in this linear network you see plateaus + + + align:start position:0% +in this linear network you see plateaus +and sudden transitions right and + + align:start position:0% +and sudden transitions right and + + + align:start position:0% +and sudden transitions right and +actually interestingly enough even in + + align:start position:0% +actually interestingly enough even in + + + align:start position:0% +actually interestingly enough even in +this very deep linear network you see + + align:start position:0% +this very deep linear network you see + + + align:start position:0% +this very deep linear network you see +faster convergence from pre-trained + + align:start position:0% +faster convergence from pre-trained + + + align:start position:0% +faster convergence from pre-trained +initial conditions right so basically if + + align:start position:0% +initial conditions right so basically if + + + align:start position:0% +initial conditions right so basically if +you start from random Gaussian initial + + align:start position:0% +you start from random Gaussian initial + + + align:start position:0% +you start from random Gaussian initial +conditions you get slow learning for a + + align:start position:0% +conditions you get slow learning for a + + + align:start position:0% +conditions you get slow learning for a +while and then sudden sudden learning + + align:start position:0% +while and then sudden sudden learning + + + align:start position:0% +while and then sudden sudden learning +here relatively sudden learning year + + align:start position:0% +here relatively sudden learning year + + + align:start position:0% +here relatively sudden learning year +whereas if you pre train the network + + align:start position:0% +whereas if you pre train the network + + + align:start position:0% +whereas if you pre train the network +using greedy unsupervised learning right + + align:start position:0% +using greedy unsupervised learning right + + + align:start position:0% +using greedy unsupervised learning right +so this is the time it takes to pre + + align:start position:0% +so this is the time it takes to pre + + + align:start position:0% +so this is the time it takes to pre +train you get sudden learning in a drop + + align:start position:0% +train you get sudden learning in a drop + + + align:start position:0% +train you get sudden learning in a drop +here so remember if you go back to + + align:start position:0% +here so remember if you go back to + + + align:start position:0% +here so remember if you go back to +the original Hinton paper this was the + + align:start position:0% +the original Hinton paper this was the + + + align:start position:0% +the original Hinton paper this was the +phenomenon that started deep learning + + align:start position:0% +phenomenon that started deep learning + + + align:start position:0% +phenomenon that started deep learning +greedy unsupervised pre-training allows + + align:start position:0% +greedy unsupervised pre-training allows + + + align:start position:0% +greedy unsupervised pre-training allows +you to rapidly train very very deep + + align:start position:0% +you to rapidly train very very deep + + + align:start position:0% +you to rapidly train very very deep +neural networks so the very empirical + + align:start position:0% +neural networks so the very empirical + + + align:start position:0% +neural networks so the very empirical +phenomenon that led to the genesis of + + align:start position:0% +phenomenon that led to the genesis of + + + align:start position:0% +phenomenon that led to the genesis of +deep learning was present already in + + align:start position:0% +deep learning was present already in + + + align:start position:0% +deep learning was present already in +deep linear neural networks right so + + align:start position:0% +deep linear neural networks right so + + + align:start position:0% +deep linear neural networks right so +deeply linear neural networks in terms + + align:start position:0% +deeply linear neural networks in terms + + + align:start position:0% +deeply linear neural networks in terms +of their expressive power are crappy + + align:start position:0% +of their expressive power are crappy + + + align:start position:0% +of their expressive power are crappy +because the composition of linear + + align:start position:0% +because the composition of linear + + + align:start position:0% +because the composition of linear +operations is linear they're not good + + align:start position:0% +operations is linear they're not good + + + align:start position:0% +operations is linear they're not good +they're not a good model for deep + + align:start position:0% +they're not a good model for deep + + + align:start position:0% +they're not a good model for deep +nonlinear networks in terms of + + align:start position:0% +nonlinear networks in terms of + + + align:start position:0% +nonlinear networks in terms of +input-output mappings but they're a + + align:start position:0% +input-output mappings but they're a + + + align:start position:0% +input-output mappings but they're a +surprisingly good model theoretical toy + + align:start position:0% +surprisingly good model theoretical toy + + + align:start position:0% +surprisingly good model theoretical toy +model for modeling the dynamics of + + align:start position:0% +model for modeling the dynamics of + + + align:start position:0% +model for modeling the dynamics of +learning in nonlinear networks + + align:start position:0% +learning in nonlinear networks + + + align:start position:0% +learning in nonlinear networks +ok because because very important + + align:start position:0% +ok because because very important + + + align:start position:0% +ok because because very important +phenomena also arise in the deep linear + + align:start position:0% +phenomena also arise in the deep linear + + + align:start position:0% +phenomena also arise in the deep linear +networks and we're focusing on learning + + align:start position:0% +networks and we're focusing on learning + + + align:start position:0% +networks and we're focusing on learning +dynamics here ok so we can build + + align:start position:0% +dynamics here ok so we can build + + + align:start position:0% +dynamics here ok so we can build +intuitions for the nonlinear case by + + align:start position:0% +intuitions for the nonlinear case by + + + align:start position:0% +intuitions for the nonlinear case by +analyzing the linear case ok so we went + + align:start position:0% +analyzing the linear case ok so we went + + + align:start position:0% +analyzing the linear case ok so we went +through the three layer dynamics already + + align:start position:0% +through the three layer dynamics already + + + align:start position:0% +through the three layer dynamics already +what about the multiple layer dynamics + + align:start position:0% +what about the multiple layer dynamics + + + align:start position:0% +what about the multiple layer dynamics +so again the Jacobian can back + + align:start position:0% +so again the Jacobian can back + + + align:start position:0% +so again the Jacobian can back +propagator explode + + align:start position:0% +propagator explode + + + align:start position:0% +propagator explode +right so what we okay so again I'm going + + align:start position:0% +right so what we okay so again I'm going + + + align:start position:0% +right so what we okay so again I'm going +to make a long story short but what we + + align:start position:0% +to make a long story short but what we + + + align:start position:0% +to make a long story short but what we +find is that if you take what we tell + + align:start position:0% +find is that if you take what we tell + + + align:start position:0% +find is that if you take what we tell +you the final result what we find is + + align:start position:0% +you the final result what we find is + + + align:start position:0% +you the final result what we find is +that we find a class of weight + + align:start position:0% +that we find a class of weight + + + align:start position:0% +that we find a class of weight +initializations that allow learning time + + align:start position:0% +initializations that allow learning time + + + align:start position:0% +initializations that allow learning time +to remain constant as the depth of the + + align:start position:0% +to remain constant as the depth of the + + + align:start position:0% +to remain constant as the depth of the +network goes to infinity now I'm + + align:start position:0% +network goes to infinity now I'm + + + align:start position:0% +network goes to infinity now I'm +measuring learning time in units of + + align:start position:0% +measuring learning time in units of + + + align:start position:0% +measuring learning time in units of +learning epochs right so obviously to + + align:start position:0% +learning epochs right so obviously to + + + align:start position:0% +learning epochs right so obviously to +train a deep neural network very very + + align:start position:0% +train a deep neural network very very + + + align:start position:0% +train a deep neural network very very +deep neural network it just takes longer + + align:start position:0% +deep neural network it just takes longer + + + align:start position:0% +deep neural network it just takes longer +to compute each gradient right so in + + align:start position:0% +to compute each gradient right so in + + + align:start position:0% +to compute each gradient right so in +cutting in terms of real time of course + + align:start position:0% +cutting in terms of real time of course + + + align:start position:0% +cutting in terms of real time of course +the time will scale with the depth of + + align:start position:0% +the time will scale with the depth of + + + align:start position:0% +the time will scale with the depth of +the network but you might imagine in + + align:start position:0% +the network but you might imagine in + + + align:start position:0% +the network but you might imagine in +terms of number of gradient evaluations + + align:start position:0% +terms of number of gradient evaluations + + + align:start position:0% +terms of number of gradient evaluations +as the network gets deeper and deeper it + + align:start position:0% +as the network gets deeper and deeper it + + + align:start position:0% +as the network gets deeper and deeper it +might take longer and longer to train it + + align:start position:0% +might take longer and longer to train it + + + align:start position:0% +might take longer and longer to train it +and we show a class of initial + + align:start position:0% +and we show a class of initial + + + align:start position:0% +and we show a class of initial +conditions which that's not true as the + + align:start position:0% +conditions which that's not true as the + + + align:start position:0% +conditions which that's not true as the +as the network gets deeper and deeper + + align:start position:0% +as the network gets deeper and deeper + + + align:start position:0% +as the network gets deeper and deeper +the number of gradient evaluations you + + align:start position:0% +the number of gradient evaluations you + + + align:start position:0% +the number of gradient evaluations you +need to train the network can remain + + align:start position:0% +need to train the network can remain + + + align:start position:0% +need to train the network can remain +constant even as the depth goes to + + align:start position:0% +constant even as the depth goes to + + + align:start position:0% +constant even as the depth goes to +infinity okay even in a nonlinear + + align:start position:0% +infinity okay even in a nonlinear + + + align:start position:0% +infinity okay even in a nonlinear +network ok so let me give you the + + align:start position:0% +network ok so let me give you the + + + align:start position:0% +network ok so let me give you the +intuition for why + + align:start position:0% + + + + align:start position:0% + +okay so for example we okay and the + + align:start position:0% +okay so for example we okay and the + + + align:start position:0% +okay so for example we okay and the +classical initialization this the + + align:start position:0% +classical initialization this the + + + align:start position:0% +classical initialization this the +scleral and Benjy initialization doesn't + + align:start position:0% +scleral and Benjy initialization doesn't + + + align:start position:0% +scleral and Benjy initialization doesn't +have that but our initialization does so + + align:start position:0% +have that but our initialization does so + + + align:start position:0% +have that but our initialization does so +basically what we did was we'll start + + align:start position:0% +basically what we did was we'll start + + + align:start position:0% +basically what we did was we'll start +off with the linear networks we trained + + align:start position:0% +off with the linear networks we trained + + + align:start position:0% +off with the linear networks we trained +deep linear networks on M NIST and we + + align:start position:0% +deep linear networks on M NIST and we + + + align:start position:0% +deep linear networks on M NIST and we +scaled the depth like this right and we + + align:start position:0% +scaled the depth like this right and we + + + align:start position:0% +scaled the depth like this right and we +started with random Gaussian initial + + align:start position:0% +started with random Gaussian initial + + + align:start position:0% +started with random Gaussian initial +conditions and then ran back propagation + + align:start position:0% +conditions and then ran back propagation + + + align:start position:0% +conditions and then ran back propagation +but scaled random - the notion was + + align:start position:0% +but scaled random - the notion was + + + align:start position:0% +but scaled random - the notion was +random Gaussian initializations and we + + align:start position:0% +random Gaussian initializations and we + + + align:start position:0% +random Gaussian initializations and we +found that the training time as you + + align:start position:0% +found that the training time as you + + + align:start position:0% +found that the training time as you +might expect grew with depth this is + + align:start position:0% +might expect grew with depth this is + + + align:start position:0% +might expect grew with depth this is +training time measured a number of + + align:start position:0% +training time measured a number of + + + align:start position:0% +training time measured a number of +learning a box or a number of gradient + + align:start position:0% +learning a box or a number of gradient + + + align:start position:0% +learning a box or a number of gradient +evaluations but here what we did was we + + align:start position:0% +evaluations but here what we did was we + + + align:start position:0% +evaluations but here what we did was we +initialize the weights using random + + align:start position:0% +initialize the weights using random + + + align:start position:0% +initialize the weights using random +orthogonal weights right and then we + + align:start position:0% +orthogonal weights right and then we + + + align:start position:0% +orthogonal weights right and then we +found that the learning time didn't grow + + align:start position:0% +found that the learning time didn't grow + + + align:start position:0% +found that the learning time didn't grow +with depth and also if you pre train it + + align:start position:0% +with depth and also if you pre train it + + + align:start position:0% +with depth and also if you pre train it +it doesn't grow with depth okay so + + align:start position:0% +it doesn't grow with depth okay so + + + align:start position:0% +it doesn't grow with depth okay so +there's a dramatically different scaling + + align:start position:0% +there's a dramatically different scaling + + + align:start position:0% +there's a dramatically different scaling +and learning time between random + + align:start position:0% +and learning time between random + + + align:start position:0% +and learning time between random +Gaussian initialization and random + + align:start position:0% +Gaussian initialization and random + + + align:start position:0% +Gaussian initialization and random +orthogonal initialization why okay and + + align:start position:0% +orthogonal initialization why okay and + + + align:start position:0% +orthogonal initialization why okay and +the answer is the following right let's + + align:start position:0% +the answer is the following right let's + + + align:start position:0% +the answer is the following right let's +think about the back propagation + + align:start position:0% +think about the back propagation + + + align:start position:0% +think about the back propagation +operator let's say you want to back + + align:start position:0% +operator let's say you want to back + + + align:start position:0% +operator let's say you want to back +propagate errors from the output to the + + align:start position:0% +propagate errors from the output to the + + + align:start position:0% +propagate errors from the output to the +input right so the the back propagation + + align:start position:0% +input right so the the back propagation + + + align:start position:0% +input right so the the back propagation +operated in a linear network right it's + + align:start position:0% +operated in a linear network right it's + + + align:start position:0% +operated in a linear network right it's +just the product of weights throughout + + align:start position:0% +just the product of weights throughout + + + align:start position:0% +just the product of weights throughout +the entire network okay + + align:start position:0% +the entire network okay + + + align:start position:0% +the entire network okay +so so your your so the back if you do a + + align:start position:0% +so so your your so the back if you do a + + + align:start position:0% +so so your your so the back if you do a +random weight random Gaussian weight + + align:start position:0% +random weight random Gaussian weight + + + align:start position:0% +random weight random Gaussian weight +initialization here then the this is a + + align:start position:0% +initialization here then the this is a + + + align:start position:0% +initialization here then the this is a +product of random Gaussian matrices so + + align:start position:0% +product of random Gaussian matrices so + + + align:start position:0% +product of random Gaussian matrices so +to understand the statistical properties + + align:start position:0% +to understand the statistical properties + + + align:start position:0% +to understand the statistical properties +of back propagation you need to + + align:start position:0% +of back propagation you need to + + + align:start position:0% +of back propagation you need to +understand the statistical properties of + + align:start position:0% +understand the statistical properties of + + + align:start position:0% +understand the statistical properties of +the singular value spectrum of random + + align:start position:0% +the singular value spectrum of random + + + align:start position:0% +the singular value spectrum of random +Gaussian matrices there isn't really a + + align:start position:0% +Gaussian matrices there isn't really a + + + align:start position:0% +Gaussian matrices there isn't really a +general theory for that but we can look + + align:start position:0% +general theory for that but we can look + + + align:start position:0% +general theory for that but we can look +at it numerically and get intuition for + + align:start position:0% +at it numerically and get intuition for + + + align:start position:0% +at it numerically and get intuition for +it so the basic idea is if you have one + + align:start position:0% +it so the basic idea is if you have one + + + align:start position:0% +it so the basic idea is if you have one +random Gaussian matrix right the + + align:start position:0% +random Gaussian matrix right the + + + align:start position:0% +random Gaussian matrix right the +singular values of W are the are the + + align:start position:0% +singular values of W are the are the + + + align:start position:0% +singular values of W are the are the +eigen values of W transpose W that's a + + align:start position:0% +eigen values of W transpose W that's a + + + align:start position:0% +eigen values of W transpose W that's a +famous distribution called the Marcinko + + align:start position:0% +famous distribution called the Marcinko + + + align:start position:0% +famous distribution called the Marcinko +posterior distribution and you know + + align:start position:0% +posterior distribution and you know + + + align:start position:0% +posterior distribution and you know +they're they vary in a range that's + + align:start position:0% +they're they vary in a range that's + + + align:start position:0% +they're they vary in a range that's +order one okay so if you're back + + align:start position:0% +order one okay so if you're back + + + align:start position:0% +order one okay so if you're back +propagate through one layer you're fine + + align:start position:0% +propagate through one layer you're fine + + + align:start position:0% +propagate through one layer you're fine +right you don't get vanishing x1 + + align:start position:0% +right you don't get vanishing x1 + + + align:start position:0% +right you don't get vanishing x1 +ingredients okay but if you if you look + + align:start position:0% +ingredients okay but if you if you look + + + align:start position:0% +ingredients okay but if you if you look +at the singular values of a product of + + align:start position:0% +at the singular values of a product of + + + align:start position:0% +at the singular values of a product of +five random Gaussian matrices the + + align:start position:0% +five random Gaussian matrices the + + + align:start position:0% +five random Gaussian matrices the +singular value per spectrum gets very + + align:start position:0% +singular value per spectrum gets very + + + align:start position:0% +singular value per spectrum gets very +distorted + + align:start position:0% +distorted + + + align:start position:0% +distorted +you get a large number of single values + + align:start position:0% +you get a large number of single values + + + align:start position:0% +you get a large number of single values +that are that are close to zero and a + + align:start position:0% +that are that are close to zero and a + + + align:start position:0% +that are that are close to zero and a +long tail that you know extends up to + + align:start position:0% +long tail that you know extends up to + + + align:start position:0% +long tail that you know extends up to +four okay but if you if you do a hundred + + align:start position:0% +four okay but if you if you do a hundred + + + align:start position:0% +four okay but if you if you do a hundred +layers you get a very very large number + + align:start position:0% +layers you get a very very large number + + + align:start position:0% +layers you get a very very large number +of singular values that are close to + + align:start position:0% +of singular values that are close to + + + align:start position:0% +of singular values that are close to +zero and a very much longer tail okay + + align:start position:0% +zero and a very much longer tail okay + + + align:start position:0% +zero and a very much longer tail okay +now these this is a product of random + + align:start position:0% +now these this is a product of random + + + align:start position:0% +now these this is a product of random +Gaussian matrices so if you feed a + + align:start position:0% +Gaussian matrices so if you feed a + + + align:start position:0% +Gaussian matrices so if you feed a +random vector into this on average its + + align:start position:0% +random vector into this on average its + + + align:start position:0% +random vector into this on average its +norm will be preserved + + align:start position:0% +norm will be preserved + + + align:start position:0% +norm will be preserved +the vectors length will not change but + + align:start position:0% +the vectors length will not change but + + + align:start position:0% +the vectors length will not change but +we know that preserving the length of a + + align:start position:0% +we know that preserving the length of a + + + align:start position:0% +we know that preserving the length of a +vector is not the same as preserving + + align:start position:0% +vector is not the same as preserving + + + align:start position:0% +vector is not the same as preserving +angles between all pairs of vectors okay + + align:start position:0% +angles between all pairs of vectors okay + + + align:start position:0% +angles between all pairs of vectors okay +so actually the way that this network + + align:start position:0% +so actually the way that this network + + + align:start position:0% +so actually the way that this network +that the way that this product of random + + align:start position:0% +that the way that this product of random + + + align:start position:0% +that the way that this product of random +Gaussian matrices preserves the norm of + + align:start position:0% +Gaussian matrices preserves the norm of + + + align:start position:0% +Gaussian matrices preserves the norm of +the gradient is it does it in a very + + align:start position:0% +the gradient is it does it in a very + + + align:start position:0% +the gradient is it does it in a very +anisotropic way it takes an error vector + + align:start position:0% +anisotropic way it takes an error vector + + + align:start position:0% +anisotropic way it takes an error vector +at the output and it projects it into a + + align:start position:0% +at the output and it projects it into a + + + align:start position:0% +at the output and it projects it into a +low dimensional space corresponding to + + align:start position:0% +low dimensional space corresponding to + + + align:start position:0% +low dimensional space corresponding to +the singular values that are large and + + align:start position:0% +the singular values that are large and + + + align:start position:0% +the singular values that are large and +then it amplifies it in that space so + + align:start position:0% +then it amplifies it in that space so + + + align:start position:0% +then it amplifies it in that space so +the length is preserved but all error + + align:start position:0% +the length is preserved but all error + + + align:start position:0% +the length is preserved but all error +vectors get projected onto a low + + align:start position:0% +vectors get projected onto a low + + + align:start position:0% +vectors get projected onto a low +dimensional space and amplified so a lot + + align:start position:0% +dimensional space and amplified so a lot + + + align:start position:0% +dimensional space and amplified so a lot +of error information is lost in a + + align:start position:0% +of error information is lost in a + + + align:start position:0% +of error information is lost in a +product of random Gaussian matrices okay + + align:start position:0% +product of random Gaussian matrices okay + + + align:start position:0% +product of random Gaussian matrices okay +so that's why the Gloria and Benjy + + align:start position:0% +so that's why the Gloria and Benjy + + + align:start position:0% +so that's why the Gloria and Benjy +initial conditions work well up to depth + + align:start position:0% +initial conditions work well up to depth + + + align:start position:0% +initial conditions work well up to depth +five or six or seven but they don't work + + align:start position:0% +five or six or seven but they don't work + + + align:start position:0% +five or six or seven but they don't work +well up to depths say a hundred or in + + align:start position:0% +well up to depths say a hundred or in + + + align:start position:0% +well up to depths say a hundred or in +recurrent neural networks as well okay + + align:start position:0% +recurrent neural networks as well okay + + + align:start position:0% +recurrent neural networks as well okay +so so what can we do well a simple thing + + align:start position:0% +so so what can we do well a simple thing + + + align:start position:0% +so so what can we do well a simple thing +we can do is we can replace the the + + align:start position:0% +we can do is we can replace the the + + + align:start position:0% +we can do is we can replace the the +matrices these random matrices with a + + align:start position:0% +matrices these random matrices with a + + + align:start position:0% +matrices these random matrices with a +fog '''l matrices okay so we know that + + align:start position:0% +fog '''l matrices okay so we know that + + + align:start position:0% +fog '''l matrices okay so we know that +all the singular values of an orthogonal + + align:start position:0% +all the singular values of an orthogonal + + + align:start position:0% +all the singular values of an orthogonal +matrix are one every single one and the + + align:start position:0% +matrix are one every single one and the + + + align:start position:0% +matrix are one every single one and the +product of orthogonal matrices is + + align:start position:0% +product of orthogonal matrices is + + + align:start position:0% +product of orthogonal matrices is +orthogonal so therefore the back + + align:start position:0% +orthogonal so therefore the back + + + align:start position:0% +orthogonal so therefore the back +propagation operator has all of its + + align:start position:0% +propagation operator has all of its + + + align:start position:0% +propagation operator has all of its +singular values equal to 1 and there's + + align:start position:0% +singular values equal to 1 and there's + + + align:start position:0% +singular values equal to 1 and there's +generalizations of orthogonal matrices + + align:start position:0% +generalizations of orthogonal matrices + + + align:start position:0% +generalizations of orthogonal matrices +to two rectangular versions when when + + align:start position:0% +to two rectangular versions when when + + + align:start position:0% +to two rectangular versions when when +the layers don't have the same number of + + align:start position:0% +the layers don't have the same number of + + + align:start position:0% +the layers don't have the same number of +neurons in each layer okay so this is + + align:start position:0% +neurons in each layer okay so this is + + + align:start position:0% +neurons in each layer okay so this is +fantastic so this works really well for + + align:start position:0% +fantastic so this works really well for + + + align:start position:0% +fantastic so this works really well for +linear networks okay but how does this + + align:start position:0% +linear networks okay but how does this + + + align:start position:0% +linear networks okay but how does this +generalize to non linear networks + + align:start position:0% +generalize to non linear networks + + + align:start position:0% +generalize to non linear networks +because then you have a product of + + align:start position:0% +because then you have a product of + + + align:start position:0% +because then you have a product of +jacobians right so what happens here + + align:start position:0% +jacobians right so what happens here + + + align:start position:0% +jacobians right so what happens here +okay so what is that what is the the + + align:start position:0% +okay so what is that what is the the + + + align:start position:0% +okay so what is that what is the the +product of Jacobian so what you have is + + align:start position:0% +product of Jacobian so what you have is + + + align:start position:0% +product of Jacobian so what you have is +you have a so if we imagine how if we + + align:start position:0% +you have a so if we imagine how if we + + + align:start position:0% +you have a so if we imagine how if we +imagine how either errors back propagate + + align:start position:0% +imagine how either errors back propagate + + + align:start position:0% +imagine how either errors back propagate +to the front or how input perturbations + + align:start position:0% +to the front or how input perturbations + + + align:start position:0% +to the front or how input perturbations +back propagate + + align:start position:0% +back propagate + + + align:start position:0% +back propagate +to the to the end right it's the same + + align:start position:0% +to the to the end right it's the same + + + align:start position:0% +to the to the end right it's the same +thing so it's easier to think about + + align:start position:0% +thing so it's easier to think about + + + align:start position:0% +thing so it's easier to think about +forward propagation imagine that you + + align:start position:0% +forward propagation imagine that you + + + align:start position:0% +forward propagation imagine that you +have an input and you perturb it + + align:start position:0% +have an input and you perturb it + + + align:start position:0% +have an input and you perturb it +slightly how does the perturbation grow + + align:start position:0% +slightly how does the perturbation grow + + + align:start position:0% +slightly how does the perturbation grow +or decay well what happens is there's a + + align:start position:0% +or decay well what happens is there's a + + + align:start position:0% +or decay well what happens is there's a +linear expansion or contraction due to W + + align:start position:0% +linear expansion or contraction due to W + + + align:start position:0% +linear expansion or contraction due to W +and then this this nominator is usually + + align:start position:0% +and then this this nominator is usually + + + align:start position:0% +and then this this nominator is usually +compressive so there's a nonlinear + + align:start position:0% +compressive so there's a nonlinear + + + align:start position:0% +compressive so there's a nonlinear +compression due to the Jacobian passes + + align:start position:0% +compression due to the Jacobian passes + + + align:start position:0% +compression due to the Jacobian passes +at the diagonal Jacobian passing through + + align:start position:0% +at the diagonal Jacobian passing through + + + align:start position:0% +at the diagonal Jacobian passing through +the point wise non-linearity and then + + align:start position:0% +the point wise non-linearity and then + + + align:start position:0% +the point wise non-linearity and then +again linear modification and nonlinear + + align:start position:0% +again linear modification and nonlinear + + + align:start position:0% +again linear modification and nonlinear +compression linear modification + + align:start position:0% +compression linear modification + + + align:start position:0% +compression linear modification +nonlinear compression okay so what we + + align:start position:0% +nonlinear compression okay so what we + + + align:start position:0% +nonlinear compression okay so what we +could do is just simply choose these + + align:start position:0% +could do is just simply choose these + + + align:start position:0% +could do is just simply choose these +again to be random orthogonal matrices + + align:start position:0% +again to be random orthogonal matrices + + + align:start position:0% +again to be random orthogonal matrices +and then what happens is the growth or + + align:start position:0% +and then what happens is the growth or + + + align:start position:0% +and then what happens is the growth or +decay of perturbations is and we scale + + align:start position:0% +decay of perturbations is and we scale + + + align:start position:0% +decay of perturbations is and we scale +the we scale the random Gauss image the + + align:start position:0% +the we scale the random Gauss image the + + + align:start position:0% +the we scale the random Gauss image the +random orthogonal matrices by a scale + + align:start position:0% +random orthogonal matrices by a scale + + + align:start position:0% +random orthogonal matrices by a scale +factor to combat the nominee or + + align:start position:0% +factor to combat the nominee or + + + align:start position:0% +factor to combat the nominee or +compression and then the dynamics of + + align:start position:0% +compression and then the dynamics of + + + align:start position:0% +compression and then the dynamics of +perturbations is like this you rotate + + align:start position:0% +perturbations is like this you rotate + + + align:start position:0% +perturbations is like this you rotate +linearly scale non linearly compressed + + align:start position:0% +linearly scale non linearly compressed + + + align:start position:0% +linearly scale non linearly compressed +rotate linearly scale nonlinear compress + + align:start position:0% +rotate linearly scale nonlinear compress + + + align:start position:0% +rotate linearly scale nonlinear compress +and so on that's essentially the type of + + align:start position:0% +and so on that's essentially the type of + + + align:start position:0% +and so on that's essentially the type of +dynamics that occurs in in dynamically + + align:start position:0% +dynamics that occurs in in dynamically + + + align:start position:0% +dynamics that occurs in in dynamically +critical systems that are close to the + + align:start position:0% +critical systems that are close to the + + + align:start position:0% +critical systems that are close to the +edge of chaos you get this alternating + + align:start position:0% +edge of chaos you get this alternating + + + align:start position:0% +edge of chaos you get this alternating +phase space expansion and compression + + align:start position:0% +phase space expansion and compression + + + align:start position:0% +phase space expansion and compression +that's in different dimensions at + + align:start position:0% +that's in different dimensions at + + + align:start position:0% +that's in different dimensions at +different times okay so now you can just + + align:start position:0% +different times okay so now you can just + + + align:start position:0% +different times okay so now you can just +compute numerically under that + + align:start position:0% +compute numerically under that + + + align:start position:0% +compute numerically under that +initialization how does the product of + + align:start position:0% +initialization how does the product of + + + align:start position:0% +initialization how does the product of +Jib how does a singular value spectrum + + align:start position:0% +Jib how does a singular value spectrum + + + align:start position:0% +Jib how does a singular value spectrum +the product of Jacobian scale and it + + align:start position:0% +the product of Jacobian scale and it + + + align:start position:0% +the product of Jacobian scale and it +scales beautifully so this is the scale + + align:start position:0% +scales beautifully so this is the scale + + + align:start position:0% +scales beautifully so this is the scale +factor for the type of non-linearity + + align:start position:0% +factor for the type of non-linearity + + + align:start position:0% +factor for the type of non-linearity +that we used the hyperbolic tangent + + align:start position:0% +that we used the hyperbolic tangent + + + align:start position:0% +that we used the hyperbolic tangent +non-linearity the optimal scale factor + + align:start position:0% +non-linearity the optimal scale factor + + + align:start position:0% +non-linearity the optimal scale factor +in front of the random orthogonal matrix + + align:start position:0% +in front of the random orthogonal matrix + + + align:start position:0% +in front of the random orthogonal matrix +is 1 and you see when you choose that + + align:start position:0% +is 1 and you see when you choose that + + + align:start position:0% +is 1 and you see when you choose that +even for this was a hundred layers I + + align:start position:0% +even for this was a hundred layers I + + + align:start position:0% +even for this was a hundred layers I +believe even for a hundred layers the + + align:start position:0% +believe even for a hundred layers the + + + align:start position:0% +believe even for a hundred layers the +end-to-end Jacobian from the input to + + align:start position:0% +end-to-end Jacobian from the input to + + + align:start position:0% +end-to-end Jacobian from the input to +output has a singular value spectrum + + align:start position:0% +output has a singular value spectrum + + + align:start position:0% +output has a singular value spectrum +that remains within a range of order one + + align:start position:0% +that remains within a range of order one + + + align:start position:0% +that remains within a range of order one +if G is even slightly less than one the + + align:start position:0% +if G is even slightly less than one the + + + align:start position:0% +if G is even slightly less than one the +singular values exponentially vanished + + align:start position:0% +singular values exponentially vanished + + + align:start position:0% +singular values exponentially vanished +with depth if G is larger than one the + + align:start position:0% +with depth if G is larger than one the + + + align:start position:0% +with depth if G is larger than one the +singular values grow but actually not + + align:start position:0% +singular values grow but actually not + + + align:start position:0% +singular values grow but actually not +not as as quickly as you'd think so this + + align:start position:0% +not as as quickly as you'd think so this + + + align:start position:0% +not as as quickly as you'd think so this +is the the critically dynamical regime + + align:start position:0% +is the the critically dynamical regime + + + align:start position:0% +is the the critically dynamical regime +that at least preserves not only the + + align:start position:0% +that at least preserves not only the + + + align:start position:0% +that at least preserves not only the +norm of back propagated gradients but + + align:start position:0% +norm of back propagated gradients but + + + align:start position:0% +norm of back propagated gradients but +all angles between pairs of gradients + + align:start position:0% +all angles between pairs of gradients + + + align:start position:0% +all angles between pairs of gradients +right so it's an isotropic isotropic + + align:start position:0% +right so it's an isotropic isotropic + + + align:start position:0% +right so it's an isotropic isotropic +preservation of error information from + + align:start position:0% +preservation of error information from + + + align:start position:0% +preservation of error information from +the end of the network all the way to + + align:start position:0% +the end of the network all the way to + + + align:start position:0% +the end of the network all the way to +the beginning ok + + align:start position:0% +the beginning ok + + + align:start position:0% +the beginning ok +so does it work and it works better than + + align:start position:0% +so does it work and it works better than + + + align:start position:0% +so does it work and it works better than +other initializations even in nonlinear + + align:start position:0% +other initializations even in nonlinear + + + align:start position:0% +other initializations even in nonlinear +Network so we trained 30 layer nonlinear + + align:start position:0% +Network so we trained 30 layer nonlinear + + + align:start position:0% +Network so we trained 30 layer nonlinear +networks and the initialization works + + align:start position:0% +networks and the initialization works + + + align:start position:0% +networks and the initialization works +better and and so also interestingly + + align:start position:0% +better and and so also interestingly + + + align:start position:0% +better and and so also interestingly +enough at this critical factor you also + + align:start position:0% +enough at this critical factor you also + + + align:start position:0% +enough at this critical factor you also +achieve better generalization error and + + align:start position:0% +achieve better generalization error and + + + align:start position:0% +achieve better generalization error and +we don't have a good theory for that + + align:start position:0% +we don't have a good theory for that + + + align:start position:0% +we don't have a good theory for that +actually the test error and the training + + align:start position:0% +actually the test error and the training + + + align:start position:0% +actually the test error and the training +error of course goes goes down so okay + + align:start position:0% +error of course goes goes down so okay + + + align:start position:0% +error of course goes goes down so okay +so that's an interesting situation where + + align:start position:0% +so that's an interesting situation where + + + align:start position:0% +so that's an interesting situation where +a theory of linear networks led to a + + align:start position:0% +a theory of linear networks led to a + + + align:start position:0% +a theory of linear networks led to a +practical training advantage for + + align:start position:0% +practical training advantage for + + + align:start position:0% +practical training advantage for +nonlinear networks ok so here's another + + align:start position:0% +nonlinear networks ok so here's another + + + align:start position:0% +nonlinear networks ok so here's another +question that we had ok there's a whole + + align:start position:0% +question that we had ok there's a whole + + + align:start position:0% +question that we had ok there's a whole +like world of convex optimization we + + align:start position:0% +like world of convex optimization we + + + align:start position:0% +like world of convex optimization we +want our machine learning algorithms to + + align:start position:0% +want our machine learning algorithms to + + + align:start position:0% +want our machine learning algorithms to +correspond to convex optimization so we + + align:start position:0% +correspond to convex optimization so we + + + align:start position:0% +correspond to convex optimization so we +can find the global minimum and there + + align:start position:0% +can find the global minimum and there + + + align:start position:0% +can find the global minimum and there +are no local minima to impede us from + + align:start position:0% +are no local minima to impede us from + + + align:start position:0% +are no local minima to impede us from +finding the global minimum + + align:start position:0% +finding the global minimum + + + align:start position:0% +finding the global minimum +all right that's a conventional wisdom + + align:start position:0% +all right that's a conventional wisdom + + + align:start position:0% +all right that's a conventional wisdom +yet the deep neural network people + + align:start position:0% +yet the deep neural network people + + + align:start position:0% +yet the deep neural network people +ignore this conventional wisdom and + + align:start position:0% +ignore this conventional wisdom and + + + align:start position:0% +ignore this conventional wisdom and +train very very deep neural networks and + + align:start position:0% +train very very deep neural networks and + + + align:start position:0% +train very very deep neural networks and +don't worry about the potential + + align:start position:0% +don't worry about the potential + + + align:start position:0% +don't worry about the potential +impediments to local minima they seem to + + align:start position:0% +impediments to local minima they seem to + + + align:start position:0% +impediments to local minima they seem to +find pretty good solutions why ok is the + + align:start position:0% +find pretty good solutions why ok is the + + + align:start position:0% +find pretty good solutions why ok is the +intuition that local minima are really + + align:start position:0% +intuition that local minima are really + + + align:start position:0% +intuition that local minima are really +an impediment to nonlinear caught non + + align:start position:0% +an impediment to nonlinear caught non + + + align:start position:0% +an impediment to nonlinear caught non +convex optimization in high dimensional + + align:start position:0% +convex optimization in high dimensional + + + align:start position:0% +convex optimization in high dimensional +spaces really true ok and you might + + align:start position:0% +spaces really true ok and you might + + + align:start position:0% +spaces really true ok and you might +think that it's not true for the + + align:start position:0% +think that it's not true for the + + + align:start position:0% +think that it's not true for the +following intuitive reason right so + + align:start position:0% +following intuitive reason right so + + + align:start position:0% +following intuitive reason right so +again it's often thought the local + + align:start position:0% +again it's often thought the local + + + align:start position:0% +again it's often thought the local +minima at some high level of error in + + align:start position:0% +minima at some high level of error in + + + align:start position:0% +minima at some high level of error in +training error stand is a major + + align:start position:0% +training error stand is a major + + + align:start position:0% +training error stand is a major +impediment to non convex optimization + + align:start position:0% +impediment to non convex optimization + + + align:start position:0% +impediment to non convex optimization +ok and you know this is an example a + + align:start position:0% +ok and you know this is an example a + + + align:start position:0% +ok and you know this is an example a +two-dimensional caricature of a protein + + align:start position:0% +two-dimensional caricature of a protein + + + align:start position:0% +two-dimensional caricature of a protein +folding energy landscape and it's very + + align:start position:0% +folding energy landscape and it's very + + + align:start position:0% +folding energy landscape and it's very +rough so there's many many local minima + + align:start position:0% +rough so there's many many local minima + + + align:start position:0% +rough so there's many many local minima +and and the global minimum might be hard + + align:start position:0% +and and the global minimum might be hard + + + align:start position:0% +and and the global minimum might be hard +to find and that's true if you sort of + + align:start position:0% +to find and that's true if you sort of + + + align:start position:0% +to find and that's true if you sort of +draw a random generic surfaces over low + + align:start position:0% +draw a random generic surfaces over low + + + align:start position:0% +draw a random generic surfaces over low +dimensions those random surfaces will + + align:start position:0% +dimensions those random surfaces will + + + align:start position:0% +dimensions those random surfaces will +have many local minima but of course our + + align:start position:0% +have many local minima but of course our + + + align:start position:0% +have many local minima but of course our +intuition about geometry derived from + + align:start position:0% +intuition about geometry derived from + + + align:start position:0% +intuition about geometry derived from +our experience with a low dimensional + + align:start position:0% +our experience with a low dimensional + + + align:start position:0% +our experience with a low dimensional +world is woefully inadequate for + + align:start position:0% +world is woefully inadequate for + + + align:start position:0% +world is woefully inadequate for +thinking about geometry in high + + align:start position:0% +thinking about geometry in high + + + align:start position:0% +thinking about geometry in high +dimensional spaces ok so it turns out + + align:start position:0% +dimensional spaces ok so it turns out + + + align:start position:0% +dimensional spaces ok so it turns out +that random non convex error functions + + align:start position:0% +that random non convex error functions + + + align:start position:0% +that random non convex error functions +over high dimensional spaces local + + align:start position:0% +over high dimensional spaces local + + + align:start position:0% +over high dimensional spaces local +minima are sort of exponentially rare in + + align:start position:0% +minima are sort of exponentially rare in + + + align:start position:0% +minima are sort of exponentially rare in +the dimensionality relative to saddle + + align:start position:0% +the dimensionality relative to saddle + + + align:start position:0% +the dimensionality relative to saddle +points just intuitively imagine you have + + align:start position:0% +points just intuitively imagine you have + + + align:start position:0% +points just intuitively imagine you have +an error function over a thousand + + align:start position:0% +an error function over a thousand + + + align:start position:0% +an error function over a thousand +variables say a thousand synaptic weight + + align:start position:0% +variables say a thousand synaptic weight + + + align:start position:0% +variables say a thousand synaptic weight +it's a deep network that's a small deep + + align:start position:0% +it's a deep network that's a small deep + + + align:start position:0% +it's a deep network that's a small deep +network but anyways let's say there's a + + align:start position:0% +network but anyways let's say there's a + + + align:start position:0% +network but anyways let's say there's a +point at which the gradient and weight + + align:start position:0% +point at which the gradient and weight + + + align:start position:0% +point at which the gradient and weight +space vanishes so now there's a thousand + + align:start position:0% +space vanishes so now there's a thousand + + + align:start position:0% +space vanishes so now there's a thousand +directions in weight space you could + + align:start position:0% +directions in weight space you could + + + align:start position:0% +directions in weight space you could +move away from that from that extrema + + align:start position:0% +move away from that from that extrema + + + align:start position:0% +move away from that from that extrema +what are the chances that every single + + align:start position:0% +what are the chances that every single + + + align:start position:0% +what are the chances that every single +direction you move has positive + + align:start position:0% +direction you move has positive + + + align:start position:0% +direction you move has positive +curvature right if it's a fairly generic + + align:start position:0% +curvature right if it's a fairly generic + + + align:start position:0% +curvature right if it's a fairly generic +landscape the answer is exponentially + + align:start position:0% +landscape the answer is exponentially + + + align:start position:0% +landscape the answer is exponentially +small in the dimensionality some + + align:start position:0% +small in the dimensionality some + + + align:start position:0% +small in the dimensionality some +directions will have negative curvature + + align:start position:0% +directions will have negative curvature + + + align:start position:0% +directions will have negative curvature +some directions will have positive + + align:start position:0% +some directions will have positive + + + align:start position:0% +some directions will have positive +curvature unless your critical point is + + align:start position:0% +curvature unless your critical point is + + + align:start position:0% +curvature unless your critical point is +already at the bottom in that case most + + align:start position:0% +already at the bottom in that case most + + + align:start position:0% +already at the bottom in that case most +direction will have positive curvature + + align:start position:0% +direction will have positive curvature + + + align:start position:0% +direction will have positive curvature +or unless your critical point is at the + + align:start position:0% +or unless your critical point is at the + + + align:start position:0% +or unless your critical point is at the +top and higher than most directions no + + align:start position:0% +top and higher than most directions no + + + align:start position:0% +top and higher than most directions no +negative curvature right so statistical + + align:start position:0% +negative curvature right so statistical + + + align:start position:0% +negative curvature right so statistical +physicists have made this intuition very + + align:start position:0% +physicists have made this intuition very + + + align:start position:0% +physicists have made this intuition very +precise for random landscapes and + + align:start position:0% +precise for random landscapes and + + + align:start position:0% +precise for random landscapes and +they've developed a theory for it so + + align:start position:0% +they've developed a theory for it so + + + align:start position:0% +they've developed a theory for it so +this is a paper in Physical Review + + align:start position:0% +this is a paper in Physical Review + + + align:start position:0% +this is a paper in Physical Review +Letters by Bray and Dean so what they + + align:start position:0% +Letters by Bray and Dean so what they + + + align:start position:0% +Letters by Bray and Dean so what they +did was they imagined just a random + + align:start position:0% +did was they imagined just a random + + + align:start position:0% +did was they imagined just a random +Gaussian error landscape so what they + + align:start position:0% +Gaussian error landscape so what they + + + align:start position:0% +Gaussian error landscape so what they +did was they looked at an error + + align:start position:0% +did was they looked at an error + + + align:start position:0% +did was they looked at an error +landscape ok that's a continuous + + align:start position:0% +landscape ok that's a continuous + + + align:start position:0% +landscape ok that's a continuous +function over n dimensions but there is + + align:start position:0% +function over n dimensions but there is + + + align:start position:0% +function over n dimensions but there is +correlations it's correlated over some + + align:start position:0% +correlations it's correlated over some + + + align:start position:0% +correlations it's correlated over some +length scale so it's like a rat it's a + + align:start position:0% +length scale so it's like a rat it's a + + + align:start position:0% +length scale so it's like a rat it's a +single draw from a random Gaussian + + align:start position:0% +single draw from a random Gaussian + + + align:start position:0% +single draw from a random Gaussian +process where the kernel of the random + + align:start position:0% +process where the kernel of the random + + + align:start position:0% +process where the kernel of the random +cows of the Gaussian process is falling + + align:start position:0% +cows of the Gaussian process is falling + + + align:start position:0% +cows of the Gaussian process is falling +off with some length scale so the error + + align:start position:0% +off with some length scale so the error + + + align:start position:0% +off with some length scale so the error +at point 1 is correlated with the error + + align:start position:0% +at point 1 is correlated with the error + + + align:start position:0% +at point 1 is correlated with the error +at point 2 over some length scale and + + align:start position:0% +at point 2 over some length scale and + + + align:start position:0% +at point 2 over some length scale and +that that correlation falls off smoothly + + align:start position:0% +that that correlation falls off smoothly + + + align:start position:0% +that that correlation falls off smoothly +so it's a random smooth landscape ok but + + align:start position:0% +so it's a random smooth landscape ok but + + + align:start position:0% +so it's a random smooth landscape ok but +the correlations are local essentially + + align:start position:0% +the correlations are local essentially + + + align:start position:0% +the correlations are local essentially +and then what they did was they asked + + align:start position:0% +and then what they did was they asked + + + align:start position:0% +and then what they did was they asked +the following question Let X be a + + align:start position:0% +the following question Let X be a + + + align:start position:0% +the following question Let X be a +critical point a point where the + + align:start position:0% +critical point a point where the + + + align:start position:0% +critical point a point where the +gradient vanishes ok we can plot every + + align:start position:0% +gradient vanishes ok we can plot every + + + align:start position:0% +gradient vanishes ok we can plot every +single critical point in a two + + align:start position:0% +single critical point in a two + + + align:start position:0% +single critical point in a two +dimensional feature space + + align:start position:0% +dimensional feature space + + + align:start position:0% +dimensional feature space +what is that feature space well the + + align:start position:0% +what is that feature space well the + + + align:start position:0% +what is that feature space well the +horizontal axis is the error level of + + align:start position:0% +horizontal axis is the error level of + + + align:start position:0% +horizontal axis is the error level of +the critical point at how high on the + + align:start position:0% +the critical point at how high on the + + + align:start position:0% +the critical point at how high on the +error axis does this critical point sit + + align:start position:0% +error axis does this critical point sit + + + align:start position:0% +error axis does this critical point sit +and then this F is the fraction of + + align:start position:0% +and then this F is the fraction of + + + align:start position:0% +and then this F is the fraction of +negative eigenvalues of the Hessian at + + align:start position:0% +negative eigenvalues of the Hessian at + + + align:start position:0% +negative eigenvalues of the Hessian at +that critical point so it's the fraction + + align:start position:0% +that critical point so it's the fraction + + + align:start position:0% +that critical point so it's the fraction +of directions that curve downwards and + + align:start position:0% +of directions that curve downwards and + + + align:start position:0% +of directions that curve downwards and +the fraction ok so now a priority + + align:start position:0% +the fraction ok so now a priority + + + align:start position:0% +the fraction ok so now a priority +critical points could potentially sit + + align:start position:0% +critical points could potentially sit + + + align:start position:0% +critical points could potentially sit +anywhere in this 2 dimensional feature + + align:start position:0% +anywhere in this 2 dimensional feature + + + align:start position:0% +anywhere in this 2 dimensional feature +space right it turns out they don't they + + align:start position:0% +space right it turns out they don't they + + + align:start position:0% +space right it turns out they don't they +concentrate on a monotonically + + align:start position:0% +concentrate on a monotonically + + + align:start position:0% +concentrate on a monotonically +increasing curve that looks like this so + + align:start position:0% +increasing curve that looks like this so + + + align:start position:0% +increasing curve that looks like this so +the higher the error level of critical + + align:start position:0% +the higher the error level of critical + + + align:start position:0% +the higher the error level of critical +point the more the negative curvature + + align:start position:0% +point the more the negative curvature + + + align:start position:0% +point the more the negative curvature +directions you have + + align:start position:0% +directions you have + + + align:start position:0% +directions you have +and to be an order one distance away + + align:start position:0% +and to be an order one distance away + + + align:start position:0% +and to be an order one distance away +from this curve the probability of that + + align:start position:0% +from this curve the probability of that + + + align:start position:0% +from this curve the probability of that +happening is exponentially small in the + + align:start position:0% +happening is exponentially small in the + + + align:start position:0% +happening is exponentially small in the +dimensionality of the problem okay + + align:start position:0% +dimensionality of the problem okay + + + align:start position:0% +dimensionality of the problem okay +now what does that mean it automatically + + align:start position:0% +now what does that mean it automatically + + + align:start position:0% +now what does that mean it automatically +implies that there are no local minima + + align:start position:0% +implies that there are no local minima + + + align:start position:0% +implies that there are no local minima +at high error or at least they're + + align:start position:0% +at high error or at least they're + + + align:start position:0% +at high error or at least they're +exponentially rel rare rather to saddle + + align:start position:0% +exponentially rel rare rather to saddle + + + align:start position:0% +exponentially rel rare rather to saddle +points of a given index okay so + + align:start position:0% +points of a given index okay so + + + align:start position:0% +points of a given index okay so +basically you typically never encounter + + align:start position:0% +basically you typically never encounter + + + align:start position:0% +basically you typically never encounter +local minimum at high error right that + + align:start position:0% +local minimum at high error right that + + + align:start position:0% +local minimum at high error right that +would be stuff that sits here and + + align:start position:0% +would be stuff that sits here and + + + align:start position:0% +would be stuff that sits here and +there's nothing here okay second if you + + align:start position:0% +there's nothing here okay second if you + + + align:start position:0% +there's nothing here okay second if you +are a local minimum which means on this + + align:start position:0% +are a local minimum which means on this + + + align:start position:0% +are a local minimum which means on this +axis you're at the bottom then your + + align:start position:0% +axis you're at the bottom then your + + + align:start position:0% +axis you're at the bottom then your +error level must be very very close to + + align:start position:0% +error level must be very very close to + + + align:start position:0% +error level must be very very close to +the global minimum okay so if you're if + + align:start position:0% +the global minimum okay so if you're if + + + align:start position:0% +the global minimum okay so if you're if +you get stuck in a local minimum you're + + align:start position:0% +you get stuck in a local minimum you're + + + align:start position:0% +you get stuck in a local minimum you're +already closed an error to the global + + align:start position:0% +already closed an error to the global + + + align:start position:0% +already closed an error to the global +minimum yeah so if you're a local + + align:start position:0% +minimum yeah so if you're a local + + + align:start position:0% +minimum yeah so if you're a local +minimum your error level will be close + + align:start position:0% +minimum your error level will be close + + + align:start position:0% +minimum your error level will be close +to the error level of the global minima + + align:start position:0% +to the error level of the global minima + + + align:start position:0% +to the error level of the global minima +why because what does it mean to be a + + align:start position:0% +why because what does it mean to be a + + + align:start position:0% +why because what does it mean to be a +local minimum it means that F is zero + + align:start position:0% +local minimum it means that F is zero + + + align:start position:0% +local minimum it means that F is zero +the fraction of negative curvature + + align:start position:0% +the fraction of negative curvature + + + align:start position:0% +the fraction of negative curvature +eigenvalues lasting is zero and this is + + align:start position:0% +eigenvalues lasting is zero and this is + + + align:start position:0% +eigenvalues lasting is zero and this is +the distribution of error levels of such + + align:start position:0% +the distribution of error levels of such + + + align:start position:0% +the distribution of error levels of such +critical points they're strongly peaked + + align:start position:0% +critical points they're strongly peaked + + + align:start position:0% +critical points they're strongly peaked +at this value which is the value of the + + align:start position:0% +at this value which is the value of the + + + align:start position:0% +at this value which is the value of the +global minimum essentially there's + + align:start position:0% +global minimum essentially there's + + + align:start position:0% +global minimum essentially there's +nothing out here okay all right now in + + align:start position:0% +nothing out here okay all right now in + + + align:start position:0% +nothing out here okay all right now in +physics there's this well-known + + align:start position:0% +physics there's this well-known + + + align:start position:0% +physics there's this well-known +principle called universality there are + + align:start position:0% +principle called universality there are + + + align:start position:0% +principle called universality there are +certain questions whose answers don't + + align:start position:0% +certain questions whose answers don't + + + align:start position:0% +certain questions whose answers don't +depend on the details for example + + align:start position:0% +depend on the details for example + + + align:start position:0% +depend on the details for example +certain critical exponents in the liquid + + align:start position:0% +certain critical exponents in the liquid + + + align:start position:0% +certain critical exponents in the liquid +gas phase transition are the exactly the + + align:start position:0% +gas phase transition are the exactly the + + + align:start position:0% +gas phase transition are the exactly the +same as critical exponents in the + + align:start position:0% +same as critical exponents in the + + + align:start position:0% +same as critical exponents in the +ferromagnetic phase transition because + + align:start position:0% +ferromagnetic phase transition because + + + align:start position:0% +ferromagnetic phase transition because +the symmetry and dimensionality the + + align:start position:0% +the symmetry and dimensionality the + + + align:start position:0% +the symmetry and dimensionality the +order parameter density in the case of + + align:start position:0% +order parameter density in the case of + + + align:start position:0% +order parameter density in the case of +liquid and magnetization in the in the + + align:start position:0% +liquid and magnetization in the in the + + + align:start position:0% +liquid and magnetization in the in the +case of ferromagnets are the same so + + align:start position:0% +case of ferromagnets are the same so + + + align:start position:0% +case of ferromagnets are the same so +there's certain questions whose answers + + align:start position:0% +there's certain questions whose answers + + + align:start position:0% +there's certain questions whose answers +don't depend on the detail they only + + align:start position:0% +don't depend on the detail they only + + + align:start position:0% +don't depend on the detail they only +depend on the symmetry and + + align:start position:0% +depend on the symmetry and + + + align:start position:0% +depend on the symmetry and +dimensionality of the problem so one + + align:start position:0% +dimensionality of the problem so one + + + align:start position:0% +dimensionality of the problem so one +might think that this qualitative + + align:start position:0% +might think that this qualitative + + + align:start position:0% +might think that this qualitative +prediction is true in just generic high + + align:start position:0% +prediction is true in just generic high + + + align:start position:0% +prediction is true in just generic high +dimensional error landscapes now the + + align:start position:0% +dimensional error landscapes now the + + + align:start position:0% +dimensional error landscapes now the +computer scientist would say no no no no + + align:start position:0% +computer scientist would say no no no no + + + align:start position:0% +computer scientist would say no no no no +no no no your random landscapes are a + + align:start position:0% +no no no your random landscapes are a + + + align:start position:0% +no no no your random landscapes are a +horrible model for our error landscapes + + align:start position:0% +horrible model for our error landscapes + + + align:start position:0% +horrible model for our error landscapes +of deep neural networks trained on Emma + + align:start position:0% +of deep neural networks trained on Emma + + + align:start position:0% +of deep neural networks trained on Emma +stand in CFR 10 and and so on and so + + align:start position:0% +stand in CFR 10 and and so on and so + + + align:start position:0% +stand in CFR 10 and and so on and so +forth + + align:start position:0% +forth + + + align:start position:0% +forth +you're completely irrelevant to us + + align:start position:0% +you're completely irrelevant to us + + + align:start position:0% +you're completely irrelevant to us +because we're doing something special + + align:start position:0% +because we're doing something special + + + align:start position:0% +because we're doing something special +we're not doing something random we have + + align:start position:0% +we're not doing something random we have + + + align:start position:0% +we're not doing something random we have +a lot of structure okay the physicist + + align:start position:0% +a lot of structure okay the physicist + + + align:start position:0% +a lot of structure okay the physicist +might counter well you know you just + + align:start position:0% +might counter well you know you just + + + align:start position:0% +might counter well you know you just +have a high dimensional problem and just + + align:start position:0% +have a high dimensional problem and just + + + align:start position:0% +have a high dimensional problem and just +the basic intuition that in + + align:start position:0% +the basic intuition that in + + + align:start position:0% +the basic intuition that in +my dimensions it's very hard to have all + + align:start position:0% +my dimensions it's very hard to have all + + + align:start position:0% +my dimensions it's very hard to have all +directions curved up at high at a + + align:start position:0% +directions curved up at high at a + + + align:start position:0% +directions curved up at high at a +critical point high error should also + + align:start position:0% +critical point high error should also + + + align:start position:0% +critical point high error should also +hold true in your problem okay but of + + align:start position:0% +hold true in your problem okay but of + + + align:start position:0% +hold true in your problem okay but of +course we'll never get anywhere if we + + align:start position:0% +course we'll never get anywhere if we + + + align:start position:0% +course we'll never get anywhere if we +stop there right we have to move over + + align:start position:0% +stop there right we have to move over + + + align:start position:0% +stop there right we have to move over +into your lands which is also my land + + align:start position:0% +into your lands which is also my land + + + align:start position:0% +into your lands which is also my land +and and and just simulate the system so + + align:start position:0% +and and and just simulate the system so + + + align:start position:0% +and and and just simulate the system so +oftentimes you know biologists and + + align:start position:0% +oftentimes you know biologists and + + + align:start position:0% +oftentimes you know biologists and +computer scientists don't believe a + + align:start position:0% +computer scientists don't believe a + + + align:start position:0% +computer scientists don't believe a +theory until they see the simulation + + align:start position:0% +theory until they see the simulation + + + align:start position:0% +theory until they see the simulation +okay so what we'll do is we'll search + + align:start position:0% +okay so what we'll do is we'll search + + + align:start position:0% +okay so what we'll do is we'll search +for critical points in the error + + align:start position:0% +for critical points in the error + + + align:start position:0% +for critical points in the error +landscape of deep neural networks and + + align:start position:0% +landscape of deep neural networks and + + + align:start position:0% +landscape of deep neural networks and +that's what we did so what we did was we + + align:start position:0% +that's what we did so what we did was we + + + align:start position:0% +that's what we did so what we did was we +use Newton's method okay to find + + align:start position:0% +use Newton's method okay to find + + + align:start position:0% +use Newton's method okay to find +critical points so it turns out that + + align:start position:0% +critical points so it turns out that + + + align:start position:0% +critical points so it turns out that +Newton's method is attracted to saddles + + align:start position:0% +Newton's method is attracted to saddles + + + align:start position:0% +Newton's method is attracted to saddles +right so Newton's method will descend in + + align:start position:0% +right so Newton's method will descend in + + + align:start position:0% +right so Newton's method will descend in +the positive curvature direction that it + + align:start position:0% +the positive curvature direction that it + + + align:start position:0% +the positive curvature direction that it +will ascend in the negative curvature + + align:start position:0% +will ascend in the negative curvature + + + align:start position:0% +will ascend in the negative curvature +direction because Newton's method is + + align:start position:0% +direction because Newton's method is + + + align:start position:0% +direction because Newton's method is +gradient descent multiplied by the + + align:start position:0% +gradient descent multiplied by the + + + align:start position:0% +gradient descent multiplied by the +inverse of the Hessian so if the Hessian + + align:start position:0% +inverse of the Hessian so if the Hessian + + + align:start position:0% +inverse of the Hessian so if the Hessian +has a negative eigen value you take the + + align:start position:0% +has a negative eigen value you take the + + + align:start position:0% +has a negative eigen value you take the +negative gradient multiply it by the + + align:start position:0% +negative gradient multiply it by the + + + align:start position:0% +negative gradient multiply it by the +negative eigen value to turn back around + + align:start position:0% +negative eigen value to turn back around + + + align:start position:0% +negative eigen value to turn back around +and you go uphill so Newton's method + + align:start position:0% +and you go uphill so Newton's method + + + align:start position:0% +and you go uphill so Newton's method +uncorrect it is attracted to saddle + + align:start position:0% +uncorrect it is attracted to saddle + + + align:start position:0% +uncorrect it is attracted to saddle +points okay so what we did was we looked + + align:start position:0% +points okay so what we did was we looked + + + align:start position:0% +points okay so what we did was we looked +at the error landscape of deep neural + + align:start position:0% +at the error landscape of deep neural + + + align:start position:0% +at the error landscape of deep neural +networks trained on em missed and c510 + + align:start position:0% +networks trained on em missed and c510 + + + align:start position:0% +networks trained on em missed and c510 +and we just plotted the prediction of + + align:start position:0% +and we just plotted the prediction of + + + align:start position:0% +and we just plotted the prediction of +random landscape theory right and what + + align:start position:0% +random landscape theory right and what + + + align:start position:0% +random landscape theory right and what +we found was exactly qualitative either + + align:start position:0% +we found was exactly qualitative either + + + align:start position:0% +we found was exactly qualitative either +prediction we took each critical point + + align:start position:0% +prediction we took each critical point + + + align:start position:0% +prediction we took each critical point +and plotted in this two dimensional + + align:start position:0% +and plotted in this two dimensional + + + align:start position:0% +and plotted in this two dimensional +feature space and we found that the + + align:start position:0% +feature space and we found that the + + + align:start position:0% +feature space and we found that the +critical points concentrated on a + + align:start position:0% +critical points concentrated on a + + + align:start position:0% +critical points concentrated on a +monotonically increasing curve which + + align:start position:0% +monotonically increasing curve which + + + align:start position:0% +monotonically increasing curve which +again shows that there are no local + + align:start position:0% +again shows that there are no local + + + align:start position:0% +again shows that there are no local +minima at high error and if you're a + + align:start position:0% +minima at high error and if you're a + + + align:start position:0% +minima at high error and if you're a +local minimum your error is close to at + + align:start position:0% +local minimum your error is close to at + + + align:start position:0% +local minimum your error is close to at +least the the lowest error minimum that + + align:start position:0% +least the the lowest error minimum that + + + align:start position:0% +least the the lowest error minimum that +we found we can't guarantee that the + + align:start position:0% +we found we can't guarantee that the + + + align:start position:0% +we found we can't guarantee that the +lowest error minimum we found is a + + align:start position:0% +lowest error minimum we found is a + + + align:start position:0% +lowest error minimum we found is a +global minimum but qualitatively the + + align:start position:0% +global minimum but qualitatively the + + + align:start position:0% +global minimum but qualitatively the +structure holds okay now the issue is + + align:start position:0% +structure holds okay now the issue is + + + align:start position:0% +structure holds okay now the issue is +what can we do about it so what this is + + align:start position:0% +what can we do about it so what this is + + + align:start position:0% +what can we do about it so what this is +telling us that even in these problems + + align:start position:0% +telling us that even in these problems + + + align:start position:0% +telling us that even in these problems +of practical interest saddle points + + align:start position:0% +of practical interest saddle points + + + align:start position:0% +of practical interest saddle points +might stand as the major impediment to + + align:start position:0% +might stand as the major impediment to + + + align:start position:0% +might stand as the major impediment to +optimization right because saddle points + + align:start position:0% +optimization right because saddle points + + + align:start position:0% +optimization right because saddle points +can trap you you know you might get you + + align:start position:0% +can trap you you know you might get you + + + align:start position:0% +can trap you you know you might get you +might go down here and then there might + + align:start position:0% +might go down here and then there might + + + align:start position:0% +might go down here and then there might +be a very slowly curving negative + + align:start position:0% +be a very slowly curving negative + + + align:start position:0% +be a very slowly curving negative +curvature direction that might take you + + align:start position:0% +curvature direction that might take you + + + align:start position:0% +curvature direction that might take you +a while to escape in fact in the + + align:start position:0% +a while to escape in fact in the + + + align:start position:0% +a while to escape in fact in the +learning dynamics that I showed in these + + align:start position:0% +learning dynamics that I showed in these + + + align:start position:0% +learning dynamics that I showed in these +transitions in learning hierarchical + + align:start position:0% +transitions in learning hierarchical + + + align:start position:0% +transitions in learning hierarchical +structure the thing controlling the + + align:start position:0% +structure the thing controlling the + + + align:start position:0% +structure the thing controlling the +transitions with the existence of saddle + + align:start position:0% +transitions with the existence of saddle + + + align:start position:0% +transitions with the existence of saddle +points and weight space of the linear + + align:start position:0% +points and weight space of the linear + + + align:start position:0% +points and weight space of the linear +neural + + align:start position:0% +neural + + + align:start position:0% +neural +and so the the part of no learning + + align:start position:0% +and so the the part of no learning + + + align:start position:0% +and so the the part of no learning +correspond to to sort of falling down + + align:start position:0% +correspond to to sort of falling down + + + align:start position:0% +correspond to to sort of falling down +this direction slowly and then the rapid + + align:start position:0% +this direction slowly and then the rapid + + + align:start position:0% +this direction slowly and then the rapid +learning on to eventually coming out + + align:start position:0% +learning on to eventually coming out + + + align:start position:0% +learning on to eventually coming out +this way okay so how do we how do we do + + align:start position:0% +this way okay so how do we how do we do + + + align:start position:0% +this way okay so how do we how do we do +that well what we can do is we can do a + + align:start position:0% +that well what we can do is we can do a + + + align:start position:0% +that well what we can do is we can do a +simple modification to Newton's method + + align:start position:0% +simple modification to Newton's method + + + align:start position:0% +simple modification to Newton's method +which instead of dividing by the Hessian + + align:start position:0% +which instead of dividing by the Hessian + + + align:start position:0% +which instead of dividing by the Hessian +we divide by the absolute value of the + + align:start position:0% +we divide by the absolute value of the + + + align:start position:0% +we divide by the absolute value of the +Hessian and again I should say that this + + align:start position:0% +Hessian and again I should say that this + + + align:start position:0% +Hessian and again I should say that this +was done in collaboration yoshua bengio + + align:start position:0% +was done in collaboration yoshua bengio + + + align:start position:0% +was done in collaboration yoshua bengio +slab and a set of fantastic graduate + + align:start position:0% +slab and a set of fantastic graduate + + + align:start position:0% +slab and a set of fantastic graduate +students in yoshua bengio slab did all + + align:start position:0% +students in yoshua bengio slab did all + + + align:start position:0% +students in yoshua bengio slab did all +of this work on the training and testing + + align:start position:0% +of this work on the training and testing + + + align:start position:0% +of this work on the training and testing +of these predictions okay so what we we + + align:start position:0% +of these predictions okay so what we we + + + align:start position:0% +of these predictions okay so what we we +suggested was you know the offending + + align:start position:0% +suggested was you know the offending + + + align:start position:0% +suggested was you know the offending +thing is dividing by negative + + align:start position:0% +thing is dividing by negative + + + align:start position:0% +thing is dividing by negative +eigenvalues so just take the absolute + + align:start position:0% +eigenvalues so just take the absolute + + + align:start position:0% +eigenvalues so just take the absolute +value of the Hessian which by definition + + align:start position:0% +value of the Hessian which by definition + + + align:start position:0% +value of the Hessian which by definition +I mean take the Hessian compute its + + align:start position:0% +I mean take the Hessian compute its + + + align:start position:0% +I mean take the Hessian compute its +eigenvalues and replace each negative + + align:start position:0% +eigenvalues and replace each negative + + + align:start position:0% +eigenvalues and replace each negative +one with its absolute value okay so that + + align:start position:0% +one with its absolute value okay so that + + + align:start position:0% +one with its absolute value okay so that +will obviously get repelled by saddles + + align:start position:0% +will obviously get repelled by saddles + + + align:start position:0% +will obviously get repelled by saddles +all right and and that actually works + + align:start position:0% +all right and and that actually works + + + align:start position:0% +all right and and that actually works +really really well and there's a way to + + align:start position:0% +really really well and there's a way to + + + align:start position:0% +really really well and there's a way to +derive this algorithm in a way that + + align:start position:0% +derive this algorithm in a way that + + + align:start position:0% +derive this algorithm in a way that +makes sense even far from saddles using + + align:start position:0% +makes sense even far from saddles using + + + align:start position:0% +makes sense even far from saddles using +by minimizing a linear approximation to + + align:start position:0% +by minimizing a linear approximation to + + + align:start position:0% +by minimizing a linear approximation to +F within a trust region in which the + + align:start position:0% +F within a trust region in which the + + + align:start position:0% +F within a trust region in which the +linear and quadratic approximations + + align:start position:0% +linear and quadratic approximations + + + align:start position:0% +linear and quadratic approximations +agree okay so let me just show you first + + align:start position:0% +agree okay so let me just show you first + + + align:start position:0% +agree okay so let me just show you first +that it works so that this is the most + + align:start position:0% +that it works so that this is the most + + + align:start position:0% +that it works so that this is the most +dramatic plot so basically what we did + + align:start position:0% +dramatic plot so basically what we did + + + align:start position:0% +dramatic plot so basically what we did +was we did stochastic gradient descent + + align:start position:0% +was we did stochastic gradient descent + + + align:start position:0% +was we did stochastic gradient descent +right for awhile and then it seemed like + + align:start position:0% +right for awhile and then it seemed like + + + align:start position:0% +right for awhile and then it seemed like +the error as a function of training time + + align:start position:0% +the error as a function of training time + + + align:start position:0% +the error as a function of training time +plateaued both for a deep autoencoder + + align:start position:0% +plateaued both for a deep autoencoder + + + align:start position:0% +plateaued both for a deep autoencoder +and a recurrent neural network problem + + align:start position:0% +and a recurrent neural network problem + + + align:start position:0% +and a recurrent neural network problem +so when the error is a function of + + align:start position:0% +so when the error is a function of + + + align:start position:0% +so when the error is a function of +training time plateaus that sort of + + align:start position:0% +training time plateaus that sort of + + + align:start position:0% +training time plateaus that sort of +interpreted as the fact that you're + + align:start position:0% +interpreted as the fact that you're + + + align:start position:0% +interpreted as the fact that you're +stuck in a local minimum right but + + align:start position:0% +stuck in a local minimum right but + + + align:start position:0% +stuck in a local minimum right but +actually when we switch to this what we + + align:start position:0% +actually when we switch to this what we + + + align:start position:0% +actually when we switch to this what we +call the saddle free Newton method the + + align:start position:0% +call the saddle free Newton method the + + + align:start position:0% +call the saddle free Newton method the +error suddenly drops again so this was + + align:start position:0% +error suddenly drops again so this was + + + align:start position:0% +error suddenly drops again so this was +an illusory signature of a local minimum + + align:start position:0% +an illusory signature of a local minimum + + + align:start position:0% +an illusory signature of a local minimum +it was actually a saddle point with + + align:start position:0% +it was actually a saddle point with + + + align:start position:0% +it was actually a saddle point with +probably a very shallow negative + + align:start position:0% +probably a very shallow negative + + + align:start position:0% +probably a very shallow negative +curvature direction it was hard to + + align:start position:0% +curvature direction it was hard to + + + align:start position:0% +curvature direction it was hard to +escape and then we switched to our + + align:start position:0% +escape and then we switched to our + + + align:start position:0% +escape and then we switched to our +algorithm we could escape it okay and + + align:start position:0% +algorithm we could escape it okay and + + + align:start position:0% +algorithm we could escape it okay and +and and you know that what these curves + + align:start position:0% +and and you know that what these curves + + + align:start position:0% +and and you know that what these curves +show is that we do do better in the + + align:start position:0% +show is that we do do better in the + + + align:start position:0% +show is that we do do better in the +final training error as well so now how + + align:start position:0% +final training error as well so now how + + + align:start position:0% +final training error as well so now how +do we train deep neural networks with + + align:start position:0% +do we train deep neural networks with + + + align:start position:0% +do we train deep neural networks with +thousands of layers and actually how do + + align:start position:0% +thousands of layers and actually how do + + + align:start position:0% +thousands of layers and actually how do +we how do we model complex probability + + align:start position:0% +we how do we model complex probability + + + align:start position:0% +we how do we model complex probability +distributions so we want to we want to + + align:start position:0% +distributions so we want to we want to + + + align:start position:0% +distributions so we want to we want to +sample from very very complex + + align:start position:0% +sample from very very complex + + + align:start position:0% +sample from very very complex +probability distributions and do complex + + align:start position:0% +probability distributions and do complex + + + align:start position:0% +probability distributions and do complex +distributional learning + + align:start position:0% +distributional learning + + + align:start position:0% +distributional learning +right so this was done by a fantastic + + align:start position:0% +right so this was done by a fantastic + + + align:start position:0% +right so this was done by a fantastic +postdoc of mine Joshua Sol Dickstein so + + align:start position:0% +postdoc of mine Joshua Sol Dickstein so + + + align:start position:0% +postdoc of mine Joshua Sol Dickstein so +we were going to Berkeley for this nanak + + align:start position:0% +we were going to Berkeley for this nanak + + + align:start position:0% +we were going to Berkeley for this nanak +Cobra missile mechanics meetings and + + align:start position:0% +Cobra missile mechanics meetings and + + + align:start position:0% +Cobra missile mechanics meetings and +things like that and there's been lots + + align:start position:0% +things like that and there's been lots + + + align:start position:0% +things like that and there's been lots +of advances in our computer system + + align:start position:0% +of advances in our computer system + + + align:start position:0% +of advances in our computer system +mechanics where you can show that + + align:start position:0% +mechanics where you can show that + + + align:start position:0% +mechanics where you can show that +roughly speaking the second law of + + align:start position:0% +roughly speaking the second law of + + + align:start position:0% +roughly speaking the second law of +thermodynamics which says that things + + align:start position:0% +thermodynamics which says that things + + + align:start position:0% +thermodynamics which says that things +get more and more disordered with time + + align:start position:0% +get more and more disordered with time + + + align:start position:0% +get more and more disordered with time +can be transiently violated in small + + align:start position:0% +can be transiently violated in small + + + align:start position:0% +can be transiently violated in small +systems or short periods of time so you + + align:start position:0% +systems or short periods of time so you + + + align:start position:0% +systems or short periods of time so you +can spontaneously generate order + + align:start position:0% +can spontaneously generate order + + + align:start position:0% +can spontaneously generate order +okay so let's so I'll just go through + + align:start position:0% +okay so let's so I'll just go through + + + align:start position:0% +okay so let's so I'll just go through +this again very quickly so so here's the + + align:start position:0% +this again very quickly so so here's the + + + align:start position:0% +this again very quickly so so here's the +basic idea let's say you have a + + align:start position:0% +basic idea let's say you have a + + + align:start position:0% +basic idea let's say you have a +complicated probability distribution + + align:start position:0% +complicated probability distribution + + + align:start position:0% +complicated probability distribution +let's just destroy it let's feed that + + align:start position:0% +let's just destroy it let's feed that + + + align:start position:0% +let's just destroy it let's feed that +probability distribution through + + align:start position:0% +probability distribution through + + + align:start position:0% +probability distribution through +diffusion to turn it into a simple + + align:start position:0% +diffusion to turn it into a simple + + + align:start position:0% +diffusion to turn it into a simple +distribution maybe an isotropic Gaussian + + align:start position:0% +distribution maybe an isotropic Gaussian + + + align:start position:0% +distribution maybe an isotropic Gaussian +and we keep a record of that destruction + + align:start position:0% +and we keep a record of that destruction + + + align:start position:0% +and we keep a record of that destruction +of structure and then we try to reverse + + align:start position:0% +of structure and then we try to reverse + + + align:start position:0% +of structure and then we try to reverse +time in that process by using deep + + align:start position:0% +time in that process by using deep + + + align:start position:0% +time in that process by using deep +neural networks to reverse time and then + + align:start position:0% +neural networks to reverse time and then + + + align:start position:0% +neural networks to reverse time and then +essentially create structure from noise + + align:start position:0% +essentially create structure from noise + + + align:start position:0% +essentially create structure from noise +and then you have a very very simple way + + align:start position:0% +and then you have a very very simple way + + + align:start position:0% +and then you have a very very simple way +to sample from complex distributions if + + align:start position:0% +to sample from complex distributions if + + + align:start position:0% +to sample from complex distributions if +you can train the neural network which + + align:start position:0% +you can train the neural network which + + + align:start position:0% +you can train the neural network which +is you just sample noise and you feed it + + align:start position:0% +is you just sample noise and you feed it + + + align:start position:0% +is you just sample noise and you feed it +through a deterministic neural network + + align:start position:0% +through a deterministic neural network + + + align:start position:0% +through a deterministic neural network +and that constants a sample from a + + align:start position:0% +and that constants a sample from a + + + align:start position:0% +and that constants a sample from a +complex distribution and so this was + + align:start position:0% +complex distribution and so this was + + + align:start position:0% +complex distribution and so this was +inspired by recent results in non + + align:start position:0% +inspired by recent results in non + + + align:start position:0% +inspired by recent results in non +equilibrium static so the basic idea + + align:start position:0% +equilibrium static so the basic idea + + + align:start position:0% +equilibrium static so the basic idea +again is you know let's imagine that you + + align:start position:0% +again is you know let's imagine that you + + + align:start position:0% +again is you know let's imagine that you +have a very complex distribution + + align:start position:0% +have a very complex distribution + + + align:start position:0% +have a very complex distribution +corresponding to this density of dye you + + align:start position:0% +corresponding to this density of dye you + + + align:start position:0% +corresponding to this density of dye you +diffuse for a while it becomes a simpler + + align:start position:0% +diffuse for a while it becomes a simpler + + + align:start position:0% +diffuse for a while it becomes a simpler +distribution eventually become uniform + + align:start position:0% +distribution eventually become uniform + + + align:start position:0% +distribution eventually become uniform +you keep a destruction now you if you if + + align:start position:0% +you keep a destruction now you if you if + + + align:start position:0% +you keep a destruction now you if you if +your reverse process of diffusion you'll + + align:start position:0% +your reverse process of diffusion you'll + + + align:start position:0% +your reverse process of diffusion you'll +never go from this back to this but if + + align:start position:0% +never go from this back to this but if + + + align:start position:0% +never go from this back to this but if +your reverse process is a neural network + + align:start position:0% +your reverse process is a neural network + + + align:start position:0% +your reverse process is a neural network +trained to do it you might be able to do + + align:start position:0% +trained to do it you might be able to do + + + align:start position:0% +trained to do it you might be able to do +it okay so that's the basic idea so + + align:start position:0% +it okay so that's the basic idea so + + + align:start position:0% +it okay so that's the basic idea so +that's what we did and I'll just show + + align:start position:0% +that's what we did and I'll just show + + + align:start position:0% +that's what we did and I'll just show +you some nice movies to show that it + + align:start position:0% +you some nice movies to show that it + + + align:start position:0% +you some nice movies to show that it +works this is the classical toy model + + align:start position:0% +works this is the classical toy model + + + align:start position:0% +works this is the classical toy model +will go to more complex models this is + + align:start position:0% +will go to more complex models this is + + + align:start position:0% +will go to more complex models this is +some distribution in two-dimensional + + align:start position:0% +some distribution in two-dimensional + + + align:start position:0% +some distribution in two-dimensional +space and so what we do is we just + + align:start position:0% +space and so what we do is we just + + + align:start position:0% +space and so what we do is we just +systematically have the points to fuse + + align:start position:0% +systematically have the points to fuse + + + align:start position:0% +systematically have the points to fuse +under Gaussian to fusion with the + + align:start position:0% +under Gaussian to fusion with the + + + align:start position:0% +under Gaussian to fusion with the +restoring force to the origin so the + + align:start position:0% +restoring force to the origin so the + + + align:start position:0% +restoring force to the origin so the +stationary distribution of that of that + + align:start position:0% +stationary distribution of that of that + + + align:start position:0% +stationary distribution of that of that +destructive process is an isotropic + + align:start position:0% +destructive process is an isotropic + + + align:start position:0% +destructive process is an isotropic +Gaussian okay and that and that's that's + + align:start position:0% +Gaussian okay and that and that's that's + + + align:start position:0% +Gaussian okay and that and that's that's +that's what happens so that's our + + align:start position:0% +that's what happens so that's our + + + align:start position:0% +that's what happens so that's our +training data ire movie is the training + + align:start position:0% +training data ire movie is the training + + + align:start position:0% +training data ire movie is the training +data + + align:start position:0% +data + + + align:start position:0% +data +okay then what we do is we train a + + align:start position:0% +okay then what we do is we train a + + + align:start position:0% +okay then what we do is we train a +neural network to reverse time in that + + align:start position:0% +neural network to reverse time in that + + + align:start position:0% +neural network to reverse time in that +movie so it's an it's a neural network + + align:start position:0% +movie so it's an it's a neural network + + + align:start position:0% +movie so it's an it's a neural network +with many many layers hundreds and + + align:start position:0% +with many many layers hundreds and + + + align:start position:0% +with many many layers hundreds and +hundreds of layers right so classically + + align:start position:0% +hundreds of layers right so classically + + + align:start position:0% +hundreds of layers right so classically +training a network of hundreds of layers + + align:start position:0% +training a network of hundreds of layers + + + align:start position:0% +training a network of hundreds of layers +you have the credit assignment problem + + align:start position:0% +you have the credit assignment problem + + + align:start position:0% +you have the credit assignment problem +because you don't know what they the + + align:start position:0% +because you don't know what they the + + + align:start position:0% +because you don't know what they the +intermediate neurons are supposed to do + + align:start position:0% +intermediate neurons are supposed to do + + + align:start position:0% +intermediate neurons are supposed to do +convened the credit assignment problem + + align:start position:0% +convened the credit assignment problem + + + align:start position:0% +convened the credit assignment problem +because each layer going up to the next + + align:start position:0% +because each layer going up to the next + + + align:start position:0% +because each layer going up to the next +layer just has to go from time T to time + + align:start position:0% +layer just has to go from time T to time + + + align:start position:0% +layer just has to go from time T to time +t minus one in the in the training data + + align:start position:0% +t minus one in the in the training data + + + align:start position:0% +t minus one in the in the training data +so you have targets for all the + + align:start position:0% +so you have targets for all the + + + align:start position:0% +so you have targets for all the +intermediate layers therefore you've + + align:start position:0% +intermediate layers therefore you've + + + align:start position:0% +intermediate layers therefore you've +circumvented the credit assignment + + align:start position:0% +circumvented the credit assignment + + + align:start position:0% +circumvented the credit assignment +problem okay so it's it's relatively + + align:start position:0% +problem okay so it's it's relatively + + + align:start position:0% +problem okay so it's it's relatively +easy to train such networks and so once + + align:start position:0% +easy to train such networks and so once + + + align:start position:0% +easy to train such networks and so once +you have such a network what should be + + align:start position:0% +you have such a network what should be + + + align:start position:0% +you have such a network what should be +able to do you should be able to feed + + align:start position:0% +able to do you should be able to feed + + + align:start position:0% +able to do you should be able to feed +that neural network an isotropic + + align:start position:0% +that neural network an isotropic + + + align:start position:0% +that neural network an isotropic +Gaussian and then have that Gaussian be + + align:start position:0% +Gaussian and then have that Gaussian be + + + align:start position:0% +Gaussian and then have that Gaussian be +turned into the data distribution so + + align:start position:0% +turned into the data distribution so + + + align:start position:0% +turned into the data distribution so +that's what happens this on the right is + + align:start position:0% +that's what happens this on the right is + + + align:start position:0% +that's what happens this on the right is +a different Gaussian and we just feed it + + align:start position:0% +a different Gaussian and we just feed it + + + align:start position:0% +a different Gaussian and we just feed it +through the trained deterministic neural + + align:start position:0% +through the trained deterministic neural + + + align:start position:0% +through the trained deterministic neural +network and out pops the it's not + + align:start position:0% +network and out pops the it's not + + + align:start position:0% +network and out pops the it's not +perfect there's some data points that + + align:start position:0% +perfect there's some data points that + + + align:start position:0% +perfect there's some data points that +are over here but this is roughly the + + align:start position:0% +are over here but this is roughly the + + + align:start position:0% +are over here but this is roughly the +distribution that had learned which is + + align:start position:0% +distribution that had learned which is + + + align:start position:0% +distribution that had learned which is +similar to what it was trained on okay + + align:start position:0% +similar to what it was trained on okay + + + align:start position:0% +similar to what it was trained on okay +so now we can look at slightly more + + align:start position:0% +so now we can look at slightly more + + + align:start position:0% +so now we can look at slightly more +complicated distribution so okay so + + align:start position:0% +complicated distribution so okay so + + + align:start position:0% +complicated distribution so okay so +that's that so now we can train it on a + + align:start position:0% +that's that so now we can train it on a + + + align:start position:0% +that's that so now we can train it on a +toy model of natural images right so a + + align:start position:0% +toy model of natural images right so a + + + align:start position:0% +toy model of natural images right so a +classic toy model of natural images is + + align:start position:0% +classic toy model of natural images is + + + align:start position:0% +classic toy model of natural images is +the dead leaves model where the sampling + + align:start position:0% +the dead leaves model where the sampling + + + align:start position:0% +the dead leaves model where the sampling +process is you just throw down circles + + align:start position:0% +process is you just throw down circles + + + align:start position:0% +process is you just throw down circles +of different radii so you get a complex + + align:start position:0% +of different radii so you get a complex + + + align:start position:0% +of different radii so you get a complex +model of natural images that in count + + align:start position:0% +model of natural images that in count + + + align:start position:0% +model of natural images that in count +that has long range edges occlusion + + align:start position:0% +that has long range edges occlusion + + + align:start position:0% +that has long range edges occlusion +coherence over long length scales and so + + align:start position:0% +coherence over long length scales and so + + + align:start position:0% +coherence over long length scales and so +on and so forth so we can train the + + align:start position:0% +on and so forth so we can train the + + + align:start position:0% +on and so forth so we can train the +neural network on such distributions we + + align:start position:0% +neural network on such distributions we + + + align:start position:0% +neural network on such distributions we +train it in a convolutional fashion by + + align:start position:0% +train it in a convolutional fashion by + + + align:start position:0% +train it in a convolutional fashion by +working on local image patches and we + + align:start position:0% +working on local image patches and we + + + align:start position:0% +working on local image patches and we +convolve so information and propagate + + align:start position:0% +convolve so information and propagate + + + align:start position:0% +convolve so information and propagate +over long ranges and so again we take + + align:start position:0% +over long ranges and so again we take + + + align:start position:0% +over long ranges and so again we take +these natural images and turn them into + + align:start position:0% +these natural images and turn them into + + + align:start position:0% +these natural images and turn them into +noise keep a record of that movie and + + align:start position:0% +noise keep a record of that movie and + + + align:start position:0% +noise keep a record of that movie and +then reverse the flow of time using a + + align:start position:0% +then reverse the flow of time using a + + + align:start position:0% +then reverse the flow of time using a +deep neural network and it's okay so + + align:start position:0% +deep neural network and it's okay so + + + align:start position:0% +deep neural network and it's okay so +once we train that right we should be + + align:start position:0% +once we train that right we should be + + + align:start position:0% +once we train that right we should be +able to turn noise into the network's + + align:start position:0% +able to turn noise into the network's + + + align:start position:0% +able to turn noise into the network's +best guess as to what a dead leaves + + align:start position:0% +best guess as to what a dead leaves + + + align:start position:0% +best guess as to what a dead leaves +model would look like so this is what + + align:start position:0% +model would look like so this is what + + + align:start position:0% +model would look like so this is what +happens it's taking noise and it turns + + align:start position:0% +happens it's taking noise and it turns + + + align:start position:0% +happens it's taking noise and it turns +it into a gas + + align:start position:0% +it into a gas + + + align:start position:0% +it into a gas +okay so it's not a perfect model but it + + align:start position:0% +okay so it's not a perfect model but it + + + align:start position:0% +okay so it's not a perfect model but it +turns out log probability of dead leaves + + align:start position:0% +turns out log probability of dead leaves + + + align:start position:0% +turns out log probability of dead leaves +under this generative model that + + align:start position:0% +under this generative model that + + + align:start position:0% +under this generative model that +consists of a thousand layer deep neural + + align:start position:0% +consists of a thousand layer deep neural + + + align:start position:0% +consists of a thousand layer deep neural +network that's higher than any other + + align:start position:0% +network that's higher than any other + + + align:start position:0% +network that's higher than any other +model so far so this is currently state + + align:start position:0% +model so far so this is currently state + + + align:start position:0% +model so far so this is currently state +of the art okay and as you can see it + + align:start position:0% +of the art okay and as you can see it + + + align:start position:0% +of the art okay and as you can see it +gets long-range coherence and sharp + + align:start position:0% +gets long-range coherence and sharp + + + align:start position:0% +gets long-range coherence and sharp +edges and moreover it gets long-range + + align:start position:0% +edges and moreover it gets long-range + + + align:start position:0% +edges and moreover it gets long-range +coherence and the orientation and hard + + align:start position:0% +coherence and the orientation and hard + + + align:start position:0% +coherence and the orientation and hard +to do in in generative models of natural + + align:start position:0% +to do in in generative models of natural + + + align:start position:0% +to do in in generative models of natural +images okay now we can actually do + + align:start position:0% +images okay now we can actually do + + + align:start position:0% +images okay now we can actually do +something somewhat practical with this + + align:start position:0% +something somewhat practical with this + + + align:start position:0% +something somewhat practical with this +is we sample from the conditional so + + align:start position:0% +is we sample from the conditional so + + + align:start position:0% +is we sample from the conditional so +then we also trained it on textures okay + + align:start position:0% +then we also trained it on textures okay + + + align:start position:0% +then we also trained it on textures okay +so so so for example textures of bark + + align:start position:0% +so so so for example textures of bark + + + align:start position:0% +so so so for example textures of bark +right and we can also sample from the + + align:start position:0% +right and we can also sample from the + + + align:start position:0% +right and we can also sample from the +conditional distribution so what we can + + align:start position:0% +conditional distribution so what we can + + + align:start position:0% +conditional distribution so what we can +do is we can clamp the the pixels + + align:start position:0% +do is we can clamp the the pixels + + + align:start position:0% +do is we can clamp the the pixels +outside of a certain range replace the + + align:start position:0% +outside of a certain range replace the + + + align:start position:0% +outside of a certain range replace the +interior wouldn't make it blank and + + align:start position:0% +interior wouldn't make it blank and + + + align:start position:0% +interior wouldn't make it blank and +because the network operates in a + + align:start position:0% +because the network operates in a + + + align:start position:0% +because the network operates in a +convolutional fashion information from + + align:start position:0% +convolutional fashion information from + + + align:start position:0% +convolutional fashion information from +the boundary should propagate into the + + align:start position:0% +the boundary should propagate into the + + + align:start position:0% +the boundary should propagate into the +interior and fill it in right so if we + + align:start position:0% +interior and fill it in right so if we + + + align:start position:0% +interior and fill it in right so if we +look at that + + align:start position:0% +look at that + + + align:start position:0% +look at that +so that's white noise and the network is + + align:start position:0% +so that's white noise and the network is + + + align:start position:0% +so that's white noise and the network is +filling it in and it fills in the it + + align:start position:0% +filling it in and it fills in the it + + + align:start position:0% +filling it in and it fills in the it +fills in the best guess image okay and + + align:start position:0% +fills in the best guess image okay and + + + align:start position:0% +fills in the best guess image okay and +so again it's not identical to the + + align:start position:0% +so again it's not identical to the + + + align:start position:0% +so again it's not identical to the +original image but it does get + + align:start position:0% +original image but it does get + + + align:start position:0% +original image but it does get +long-range edge structure coherence and + + align:start position:0% +long-range edge structure coherence and + + + align:start position:0% +long-range edge structure coherence and +the orientation of the edge and smooth + + align:start position:0% +the orientation of the edge and smooth + + + align:start position:0% +the orientation of the edge and smooth +structure as well and again this is like + + align:start position:0% +structure as well and again this is like + + + align:start position:0% +structure as well and again this is like +a thousand layer neural network now + + align:start position:0% +a thousand layer neural network now + + + align:start position:0% +a thousand layer neural network now +there's some lessons here okay + + align:start position:0% +there's some lessons here okay + + + align:start position:0% +there's some lessons here okay +oftentimes when we model complex data + + align:start position:0% +oftentimes when we model complex data + + + align:start position:0% +oftentimes when we model complex data +distributions what we try to do is we + + align:start position:0% +distributions what we try to do is we + + + align:start position:0% +distributions what we try to do is we +try to create a stochastic process whose + + align:start position:0% +try to create a stochastic process whose + + + align:start position:0% +try to create a stochastic process whose +stationary distribution is the complex + + align:start position:0% +stationary distribution is the complex + + + align:start position:0% +stationary distribution is the complex +distribution right now if your + + align:start position:0% +distribution right now if your + + + align:start position:0% +distribution right now if your +distribution has multiple modes you're + + align:start position:0% +distribution has multiple modes you're + + + align:start position:0% +distribution has multiple modes you're +going to run into a mixing problem + + align:start position:0% +going to run into a mixing problem + + + align:start position:0% +going to run into a mixing problem +because it can take a stochastic process + + align:start position:0% +because it can take a stochastic process + + + align:start position:0% +because it can take a stochastic process +a long time to jump over energy barriers + + align:start position:0% +a long time to jump over energy barriers + + + align:start position:0% +a long time to jump over energy barriers +that separate the multiple modes so you + + align:start position:0% +that separate the multiple modes so you + + + align:start position:0% +that separate the multiple modes so you +always have a mixing problem that often + + align:start position:0% +always have a mixing problem that often + + + align:start position:0% +always have a mixing problem that often +times a new train system train + + align:start position:0% +times a new train system train + + + align:start position:0% +times a new train system train +publishing models you have to sample and + + align:start position:0% +publishing models you have to sample and + + + align:start position:0% +publishing models you have to sample and +then use the train the model so that + + align:start position:0% +then use the train the model so that + + + align:start position:0% +then use the train the model so that +makes training along the long that makes + + align:start position:0% +makes training along the long that makes + + + align:start position:0% +makes training along the long that makes +trailing training take a long time so + + align:start position:0% +trailing training take a long time so + + + align:start position:0% +trailing training take a long time so +what we're also doing in addition to + + align:start position:0% +what we're also doing in addition to + + + align:start position:0% +what we're also doing in addition to +circumventing the credit assignment + + align:start position:0% +circumventing the credit assignment + + + align:start position:0% +circumventing the credit assignment +problem in training very deep neural + + align:start position:0% +problem in training very deep neural + + + align:start position:0% +problem in training very deep neural +networks + + align:start position:0% +networks + + + align:start position:0% +networks +we're circumventing the mixing problem + + align:start position:0% +we're circumventing the mixing problem + + + align:start position:0% +we're circumventing the mixing problem +in training the generative model because + + align:start position:0% +in training the generative model because + + + align:start position:0% +in training the generative model because +we're not trying to model the data + + align:start position:0% +we're not trying to model the data + + + align:start position:0% +we're not trying to model the data +distribution as a stationary + + align:start position:0% +distribution as a stationary + + + align:start position:0% +distribution as a stationary +distribution of us to catch + + align:start position:0% +distribution of us to catch + + + align:start position:0% +distribution of us to catch +there would have to run for a very long + + align:start position:0% +there would have to run for a very long + + + align:start position:0% +there would have to run for a very long +time to get to the station distribution + + align:start position:0% +time to get to the station distribution + + + align:start position:0% +time to get to the station distribution +we're demanding that during training the + + align:start position:0% +we're demanding that during training the + + + align:start position:0% +we're demanding that during training the +process get to the the data distribution + + align:start position:0% +process get to the the data distribution + + + align:start position:0% +process get to the the data distribution +in a finite amount of time right so + + align:start position:0% +in a finite amount of time right so + + + align:start position:0% +in a finite amount of time right so +because during training we demand that + + align:start position:0% +because during training we demand that + + + align:start position:0% +because during training we demand that +we get to the data distribution of fine + + align:start position:0% +we get to the data distribution of fine + + + align:start position:0% +we get to the data distribution of fine +item at a time + + align:start position:0% +item at a time + + + align:start position:0% +item at a time +we're circumventing the mixing problem + + align:start position:0% +we're circumventing the mixing problem + + + align:start position:0% +we're circumventing the mixing problem +during training and that's the idea that + + align:start position:0% +during training and that's the idea that + + + align:start position:0% +during training and that's the idea that +that's idea there's lots of results now + + align:start position:0% +that's idea there's lots of results now + + + align:start position:0% +that's idea there's lots of results now +that show that you can attain + + align:start position:0% +that show that you can attain + + + align:start position:0% +that show that you can attain +information about stationary equilibrium + + align:start position:0% +information about stationary equilibrium + + + align:start position:0% +information about stationary equilibrium +distribution through non equilibrium + + align:start position:0% +distribution through non equilibrium + + + align:start position:0% +distribution through non equilibrium +trajectories okay so that now I'm done + + align:start position:0% +trajectories okay so that now I'm done + + + align:start position:0% +trajectories okay so that now I'm done +so let's see well okay so there's that + + align:start position:0% +so let's see well okay so there's that + + + align:start position:0% +so let's see well okay so there's that +ok so again you can read about all of + + align:start position:0% +ok so again you can read about all of + + + align:start position:0% +ok so again you can read about all of +this stuff in this set of papers again + + align:start position:0% +this stuff in this set of papers again + + + align:start position:0% +this stuff in this set of papers again +I'd like to thank my funding and just + + align:start position:0% +I'd like to thank my funding and just + + + align:start position:0% +I'd like to thank my funding and just +the the key players so Andrew sacks you + + align:start position:0% +the the key players so Andrew sacks you + + + align:start position:0% +the the key players so Andrew sacks you +know did the work with me on nonlinear + + align:start position:0% +know did the work with me on nonlinear + + + align:start position:0% +know did the work with me on nonlinear +learning dynamics and learning how + + align:start position:0% +learning dynamics and learning how + + + align:start position:0% +learning dynamics and learning how +academy structure joshua's addiction did + + align:start position:0% +academy structure joshua's addiction did + + + align:start position:0% +academy structure joshua's addiction did +the work on deep learning using noncom + + align:start position:0% +the work on deep learning using noncom + + + align:start position:0% +the work on deep learning using noncom +thermodynamics and the the the work and + + align:start position:0% +thermodynamics and the the the work and + + + align:start position:0% +thermodynamics and the the the work and +saddle points was a nice collaboration + + align:start position:0% +saddle points was a nice collaboration + + + align:start position:0% +saddle points was a nice collaboration +Yoshi Avengers lab and again fantastic + + align:start position:0% +Yoshi Avengers lab and again fantastic + + + align:start position:0% +Yoshi Avengers lab and again fantastic +graduate students in yoshua bengio + + align:start position:0% +graduate students in yoshua bengio + + + align:start position:0% +graduate students in yoshua bengio +Salaam okay so I think there's a lot + + align:start position:0% +Salaam okay so I think there's a lot + + + align:start position:0% +Salaam okay so I think there's a lot +more to do in terms of unifying + + align:start position:0% +more to do in terms of unifying + + + align:start position:0% +more to do in terms of unifying +neuroscience machine learning physics + + align:start position:0% +neuroscience machine learning physics + + + align:start position:0% +neuroscience machine learning physics +math statistics all of that stuff it'll + + align:start position:0% +math statistics all of that stuff it'll + + + align:start position:0% +math statistics all of that stuff it'll +keep us busy for the next century + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/p2j16ebu14U.txt b/p2j16ebu14U.txt new file mode 100644 index 0000000000000000000000000000000000000000..40d470005efd05637592d4dadac1e549b8582eff --- /dev/null +++ b/p2j16ebu14U.txt @@ -0,0 +1,73 @@ +So here's the final version of our 5-stage +pipelined data path. + +To deal with data hazards we've added stall +logic to the IF and RF input registers. + +We've also added bypass muxes on the output +of the register file read ports so we can + +route values from later in the data path if +we need to access a register value that's + +been computed but not yet written to the register +file. + +We also made a provision to insert NOPs into +the pipeline after the RF stage if the IF + +and RF stages are stalled. + +To deal with control hazards, we speculate +that the next instruction is at PC+4. + +But for JMPs and taken branches, that guess +is wrong so we added a provision for annulling + +the instruction in the IF stage. + +To deal with exceptions and interrupts we +added instruction muxes in all but the final + +pipeline stage. + +An instruction that causes an exception is +replaced by our magic BNE instruction to capture + +its PC+4 value. + +And instructions in earlier stages are annulled. + +All this extra circuitry has been added to +ensure that pipelined execution gives the + +same result as unpipelined execution. + +The use of bypassing and branch prediction +ensures that data and control hazards have + +only a small negative impact on the effective +CPI. + +This means that the much shorter clock period +translates to a large increase in instruction + +throughput. + +It's worth remembering the strategies we used +to deal with hazards: stalling, bypassing + +and speculation. + +Most execution issues can be dealt with using +one of these strategies, so keep these in + +mind if you ever need to design a high-performance +pipelined system. + +This completes our discussion of pipelining. + +We'll explore other avenues to higher processor +performance in the last lecture, which discusses + +parallel processing. \ No newline at end of file diff --git a/ptjKegETGuA.txt b/ptjKegETGuA.txt new file mode 100644 index 0000000000000000000000000000000000000000..208431fd5761e7121c882dfb9c2c5e6bd5b6427f --- /dev/null +++ b/ptjKegETGuA.txt @@ -0,0 +1,21043 @@ +align:start position:0% + +The following content is provided by MIT + + align:start position:0% +The following content is provided by MIT + + + align:start position:0% +The following content is provided by MIT +Open Courseware under a creative common + + align:start position:0% +Open Courseware under a creative common + + + align:start position:0% +Open Courseware under a creative common +license. Additional information about + + align:start position:0% +license. Additional information about + + + align:start position:0% +license. Additional information about +our license and MIT Open Courseware in + + align:start position:0% +our license and MIT Open Courseware in + + + align:start position:0% +our license and MIT Open Courseware in +general is available at ocw.mmit.edu. + + align:start position:0% + + + + align:start position:0% + +Welcome to the CDD forum. Sensing place + + align:start position:0% +Welcome to the CDD forum. Sensing place + + + align:start position:0% +Welcome to the CDD forum. Sensing place +photography is inquiry. + + align:start position:0% +photography is inquiry. + + + align:start position:0% +photography is inquiry. +Uh we have today with us Martin Kger + + align:start position:0% +Uh we have today with us Martin Kger + + + align:start position:0% +Uh we have today with us Martin Kger +who's a professor of urban planning at + + align:start position:0% +who's a professor of urban planning at + + + align:start position:0% +who's a professor of urban planning at +um from California and who interestingly + + align:start position:0% +um from California and who interestingly + + + align:start position:0% +um from California and who interestingly +enough started out in physics and got + + align:start position:0% +enough started out in physics and got + + + align:start position:0% +enough started out in physics and got +his PhD in physics before moving to + + align:start position:0% +his PhD in physics before moving to + + + align:start position:0% +his PhD in physics before moving to +planning uh and ask him how he made that + + align:start position:0% +planning uh and ask him how he made that + + + align:start position:0% +planning uh and ask him how he made that +was an interesting shift to to make that + + align:start position:0% +was an interesting shift to to make that + + + align:start position:0% +was an interesting shift to to make that +uh connection between the understanding + + align:start position:0% +uh connection between the understanding + + + align:start position:0% +uh connection between the understanding +of of + + align:start position:0% +of of + + + align:start position:0% +of of +physics and + + align:start position:0% +physics and + + + align:start position:0% +physics and +issues around the planet. I first + + align:start position:0% +issues around the planet. I first + + + align:start position:0% +issues around the planet. I first +encountered his work in the pages of + + align:start position:0% +encountered his work in the pages of + + + align:start position:0% +encountered his work in the pages of +landscape architecture magazine in a + + align:start position:0% +landscape architecture magazine in a + + + align:start position:0% +landscape architecture magazine in a +wonderful article called What's Wrong + + align:start position:0% +wonderful article called What's Wrong + + + align:start position:0% +wonderful article called What's Wrong +with Plastic Trees? It was quite + + align:start position:0% +with Plastic Trees? It was quite + + + align:start position:0% +with Plastic Trees? It was quite +provocative and is the title of a more + + align:start position:0% +provocative and is the title of a more + + + align:start position:0% +provocative and is the title of a more +recent + + align:start position:0% +recent + + + align:start position:0% +recent +book. So I think uh you'll all be set + + align:start position:0% +book. So I think uh you'll all be set + + + align:start position:0% +book. So I think uh you'll all be set +for quite a ride here of uh presentation + + align:start position:0% +for quite a ride here of uh presentation + + + align:start position:0% +for quite a ride here of uh presentation +of looking at the city uh using + + align:start position:0% +of looking at the city uh using + + + align:start position:0% +of looking at the city uh using +photography and uh as a form of research + + align:start position:0% +photography and uh as a form of research + + + align:start position:0% +photography and uh as a form of research +and Mark Schuster will be giving a few + + align:start position:0% +and Mark Schuster will be giving a few + + + align:start position:0% +and Mark Schuster will be giving a few +comments after Martin Creger's + + align:start position:0% +comments after Martin Creger's + + + align:start position:0% +comments after Martin Creger's +presentation. So welcome. Before um I + + align:start position:0% +presentation. So welcome. Before um I + + + align:start position:0% +presentation. So welcome. Before um I +turn this over to Martin, I'd like to + + align:start position:0% +turn this over to Martin, I'd like to + + + align:start position:0% +turn this over to Martin, I'd like to +announce that Leslie Tuttle will be + + align:start position:0% +announce that Leslie Tuttle will be + + + align:start position:0% +announce that Leslie Tuttle will be +speaking next Monday at 6:00 on uh title + + align:start position:0% +speaking next Monday at 6:00 on uh title + + + align:start position:0% +speaking next Monday at 6:00 on uh title +Leaving Tradition Behind. Leaving + + align:start position:0% +Leaving Tradition Behind. Leaving + + + align:start position:0% +Leaving Tradition Behind. Leaving +tradition behind which is about uh + + align:start position:0% +tradition behind which is about uh + + + align:start position:0% +tradition behind which is about uh +several generations of Muslim Kurdish + + align:start position:0% +several generations of Muslim Kurdish + + + align:start position:0% +several generations of Muslim Kurdish +women in and their families in Turkey + + align:start position:0% +women in and their families in Turkey + + + align:start position:0% +women in and their families in Turkey +and the migration of the children and + + align:start position:0% +and the migration of the children and + + + align:start position:0% +and the migration of the children and +grandchildren uh from the village to + + align:start position:0% +grandchildren uh from the village to + + + align:start position:0% +grandchildren uh from the village to +cities and then onto London. So please + + align:start position:0% +cities and then onto London. So please + + + align:start position:0% +cities and then onto London. So please +join us uh next Monday. + + align:start position:0% +join us uh next Monday. + + + align:start position:0% +join us uh next Monday. +Martin, thank you very much. Um, I'll + + align:start position:0% +Martin, thank you very much. Um, I'll + + + align:start position:0% +Martin, thank you very much. Um, I'll +explain the title which has lots of sort + + align:start position:0% +explain the title which has lots of sort + + + align:start position:0% +explain the title which has lots of sort +of $100 words in it like ambiences and + + align:start position:0% +of $100 words in it like ambiences and + + + align:start position:0% +of $100 words in it like ambiences and +choreographies and sensorium + + align:start position:0% +choreographies and sensorium + + + align:start position:0% +choreographies and sensorium +uh as I go along. Um, first of all, it's + + align:start position:0% +uh as I go along. Um, first of all, it's + + + align:start position:0% +uh as I go along. Um, first of all, it's +really very lovely to be back in 10485 + + align:start position:0% +really very lovely to be back in 10485 + + + align:start position:0% +really very lovely to be back in 10485 +after having uh left it about 20 years + + align:start position:0% +after having uh left it about 20 years + + + align:start position:0% +after having uh left it about 20 years +ago and or 22 years ago and see some of + + align:start position:0% +ago and or 22 years ago and see some of + + + align:start position:0% +ago and or 22 years ago and see some of +my old friends here and new people and + + align:start position:0% +my old friends here and new people and + + + align:start position:0% +my old friends here and new people and +people who were once uh sort of young + + align:start position:0% +people who were once uh sort of young + + + align:start position:0% +people who were once uh sort of young +and now or less young as they say and + + align:start position:0% +and now or less young as they say and + + + align:start position:0% +and now or less young as they say and +some of us who are middle-aged and now + + align:start position:0% +some of us who are middle-aged and now + + + align:start position:0% +some of us who are middle-aged and now +older. Um, so it's really nice and MIT + + align:start position:0% +older. Um, so it's really nice and MIT + + + align:start position:0% +older. Um, so it's really nice and MIT +has really quite a distinguished + + align:start position:0% +has really quite a distinguished + + + align:start position:0% +has really quite a distinguished +tradition in photography as you're + + align:start position:0% +tradition in photography as you're + + + align:start position:0% +tradition in photography as you're +probably aware of. um minor white taught + + align:start position:0% +probably aware of. um minor white taught + + + align:start position:0% +probably aware of. um minor white taught +here in the 60s I believe and uh where + + align:start position:0% +here in the 60s I believe and uh where + + + align:start position:0% +here in the 60s I believe and uh where +Jerry Weezner some thought that somehow + + align:start position:0% +Jerry Weezner some thought that somehow + + + align:start position:0% +Jerry Weezner some thought that somehow +the arts could humanize the engineers. + + align:start position:0% +the arts could humanize the engineers. + + + align:start position:0% +the arts could humanize the engineers. +I'm not sure if that's uh in fact the + + align:start position:0% +I'm not sure if that's uh in fact the + + + align:start position:0% +I'm not sure if that's uh in fact the +way to do it but it certainly was good + + align:start position:0% +way to do it but it certainly was good + + + align:start position:0% +way to do it but it certainly was good +to have uh minor white teaching here. Uh + + align:start position:0% +to have uh minor white teaching here. Uh + + + align:start position:0% +to have uh minor white teaching here. Uh +and if you my favorite thing about MIT + + align:start position:0% +and if you my favorite thing about MIT + + + align:start position:0% +and if you my favorite thing about MIT +is that if you go in E51 and E53 on the + + align:start position:0% +is that if you go in E51 and E53 on the + + + align:start position:0% +is that if you go in E51 and E53 on the +third floor at least 20 years ago there + + align:start position:0% +third floor at least 20 years ago there + + + align:start position:0% +third floor at least 20 years ago there +were photographs by Bernice Abbott of + + align:start position:0% +were photographs by Bernice Abbott of + + + align:start position:0% +were photographs by Bernice Abbott of +various physics experiments. Are they + + align:start position:0% +various physics experiments. Are they + + + align:start position:0% +various physics experiments. Are they +still there? They're in the president's + + align:start position:0% +still there? They're in the president's + + + align:start position:0% +still there? They're in the president's +office. They're spectacular images and I + + align:start position:0% +office. They're spectacular images and I + + + align:start position:0% +office. They're spectacular images and I +recommend them highly to you. Uh they + + align:start position:0% +recommend them highly to you. Uh they + + + align:start position:0% +recommend them highly to you. Uh they +used for the physical sciences study + + align:start position:0% +used for the physical sciences study + + + align:start position:0% +used for the physical sciences study +committee. Uh she was commissioned to do + + align:start position:0% +committee. Uh she was commissioned to do + + + align:start position:0% +committee. Uh she was commissioned to do +that. And if you don't know who Bernie + + align:start position:0% +that. And if you don't know who Bernie + + + align:start position:0% +that. And if you don't know who Bernie +Sabbat is, she'll come up later. Um and + + align:start position:0% +Sabbat is, she'll come up later. Um and + + + align:start position:0% +Sabbat is, she'll come up later. Um and +I'm also grateful in some sense for + + align:start position:0% +I'm also grateful in some sense for + + + align:start position:0% +I'm also grateful in some sense for +having left MIT and gone Hollywood, so + + align:start position:0% +having left MIT and gone Hollywood, so + + + align:start position:0% +having left MIT and gone Hollywood, so +to speak, as you'll see. I teach at the + + align:start position:0% +to speak, as you'll see. I teach at the + + + align:start position:0% +to speak, as you'll see. I teach at the +University of Southern California and as + + align:start position:0% +University of Southern California and as + + + align:start position:0% +University of Southern California and as +I was saying before half our faculty + + align:start position:0% +I was saying before half our faculty + + + align:start position:0% +I was saying before half our faculty +would wish if you ask them what they + + align:start position:0% +would wish if you ask them what they + + + align:start position:0% +would wish if you ask them what they +really want to do they really want to + + align:start position:0% +really want to do they really want to + + + align:start position:0% +really want to do they really want to +direct. Uh in any case uh I thought + + align:start position:0% +direct. Uh in any case uh I thought + + + align:start position:0% +direct. Uh in any case uh I thought +inquiry and sensing is a perfect theme + + align:start position:0% +inquiry and sensing is a perfect theme + + + align:start position:0% +inquiry and sensing is a perfect theme +because in fact that's what I'm up to. + + align:start position:0% +because in fact that's what I'm up to. + + + align:start position:0% +because in fact that's what I'm up to. +Let me give you a preview of what I'll + + align:start position:0% +Let me give you a preview of what I'll + + + align:start position:0% +Let me give you a preview of what I'll +be saying. Uh I gather questions should + + align:start position:0% +be saying. Uh I gather questions should + + + align:start position:0% +be saying. Uh I gather questions should +be deferred to later on so that the + + align:start position:0% +be deferred to later on so that the + + + align:start position:0% +be deferred to later on so that the +recording can go smoothly but uh I'll be + + align:start position:0% +recording can go smoothly but uh I'll be + + + align:start position:0% +recording can go smoothly but uh I'll be +glad to take on any questions. Normally + + align:start position:0% +glad to take on any questions. Normally + + + align:start position:0% +glad to take on any questions. Normally +I take them during + + align:start position:0% +I take them during + + + align:start position:0% +I take them during +um this work on photography I'll argue + + align:start position:0% +um this work on photography I'll argue + + + align:start position:0% +um this work on photography I'll argue +was a natural continuation my other work + + align:start position:0% +was a natural continuation my other work + + + align:start position:0% +was a natural continuation my other work +and what gave me the courage to pursue + + align:start position:0% +and what gave me the courage to pursue + + + align:start position:0% +and what gave me the courage to pursue +it besides getting older was the work of + + align:start position:0% +it besides getting older was the work of + + + align:start position:0% +it besides getting older was the work of +diet in the French encyclopedia of 1760 + + align:start position:0% +diet in the French encyclopedia of 1760 + + + align:start position:0% +diet in the French encyclopedia of 1760 +Charles Marviel's work of 1860 where he + + align:start position:0% +Charles Marviel's work of 1860 where he + + + align:start position:0% +Charles Marviel's work of 1860 where he +photographed Paris before it was + + align:start position:0% +photographed Paris before it was + + + align:start position:0% +photographed Paris before it was +eviscerated by Baron Houseman and Eugene + + align:start position:0% +eviscerated by Baron Houseman and Eugene + + + align:start position:0% +eviscerated by Baron Houseman and Eugene +Ajett's photographs of Paris in around + + align:start position:0% +Ajett's photographs of Paris in around + + + align:start position:0% +Ajett's photographs of Paris in around +1910 1920 uh as it slowly fully but + + align:start position:0% +1910 1920 uh as it slowly fully but + + + align:start position:0% +1910 1920 uh as it slowly fully but +wasn't modernizing yet. Uh my insight + + align:start position:0% +wasn't modernizing yet. Uh my insight + + + align:start position:0% +wasn't modernizing yet. Uh my insight +was that I didn't have to be an artistic + + align:start position:0% +was that I didn't have to be an artistic + + + align:start position:0% +was that I didn't have to be an artistic +photographer to do the work but I could + + align:start position:0% +photographer to do the work but I could + + + align:start position:0% +photographer to do the work but I could +learn an enormous amount from the + + align:start position:0% +learn an enormous amount from the + + + align:start position:0% +learn an enormous amount from the +artists and the craftsman in the field. + + align:start position:0% +artists and the craftsman in the field. + + + align:start position:0% +artists and the craftsman in the field. +Uh in other words, I didn't have to + + align:start position:0% +Uh in other words, I didn't have to + + + align:start position:0% +Uh in other words, I didn't have to +worry about whether I was going to be a + + align:start position:0% +worry about whether I was going to be a + + + align:start position:0% +worry about whether I was going to be a +great photographer, but I could learn + + align:start position:0% +great photographer, but I could learn + + + align:start position:0% +great photographer, but I could learn +tremendous amounts from the techniques + + align:start position:0% +tremendous amounts from the techniques + + + align:start position:0% +tremendous amounts from the techniques +and styles and methods. + + align:start position:0% +and styles and methods. + + + align:start position:0% +and styles and methods. +And if someone said to me, you're + + align:start position:0% +And if someone said to me, you're + + + align:start position:0% +And if someone said to me, you're +imitating uh DRO, I would say, thank + + align:start position:0% +imitating uh DRO, I would say, thank + + + align:start position:0% +imitating uh DRO, I would say, thank +God. In other words, I'm not worried + + align:start position:0% +God. In other words, I'm not worried + + + align:start position:0% +God. In other words, I'm not worried +about being original, which for an + + align:start position:0% +about being original, which for an + + + align:start position:0% +about being original, which for an +artist is crucial. I have other + + align:start position:0% +artist is crucial. I have other + + + align:start position:0% +artist is crucial. I have other +concerns. Uh there are several themes + + align:start position:0% +concerns. Uh there are several themes + + + align:start position:0% +concerns. Uh there are several themes +that come up in my work. One is I'm + + align:start position:0% +that come up in my work. One is I'm + + + align:start position:0% +that come up in my work. One is I'm +interested in repetition. I'm interested + + align:start position:0% +interested in repetition. I'm interested + + + align:start position:0% +interested in repetition. I'm interested +in phenomena that happen lots and lots + + align:start position:0% +in phenomena that happen lots and lots + + + align:start position:0% +in phenomena that happen lots and lots +and lots of times, not unique + + align:start position:0% +and lots of times, not unique + + + align:start position:0% +and lots of times, not unique +events. As you'll see, for example, I've + + align:start position:0% +events. As you'll see, for example, I've + + + align:start position:0% +events. As you'll see, for example, I've +photographed about 800 storefront + + align:start position:0% +photographed about 800 storefront + + + align:start position:0% +photographed about 800 storefront +churches in Los Angeles. + + align:start position:0% +churches in Los Angeles. + + + align:start position:0% +churches in Los Angeles. +Each one of them is special but in their + + align:start position:0% +Each one of them is special but in their + + + align:start position:0% +Each one of them is special but in their +toto there's a story to be told which I + + align:start position:0% +toto there's a story to be told which I + + + align:start position:0% +toto there's a story to be told which I +think is rather interesting. I'm + + align:start position:0% +think is rather interesting. I'm + + + align:start position:0% +think is rather interesting. I'm +interested in ordinary things not + + align:start position:0% +interested in ordinary things not + + + align:start position:0% +interested in ordinary things not +extraordinary things that happen every + + align:start position:0% +extraordinary things that happen every + + + align:start position:0% +extraordinary things that happen every +day. It doesn't mean you pay attention + + align:start position:0% +day. It doesn't mean you pay attention + + + align:start position:0% +day. It doesn't mean you pay attention +to them every day but they're + + align:start position:0% +to them every day but they're + + + align:start position:0% +to them every day but they're +around in when people talk about in + + align:start position:0% +around in when people talk about in + + + align:start position:0% +around in when people talk about in +people who do make motion pictures and + + align:start position:0% +people who do make motion pictures and + + + align:start position:0% +people who do make motion pictures and +they talk about the background town + + align:start position:0% +they talk about the background town + + + align:start position:0% +they talk about the background town +sound of a room because no room is + + align:start position:0% +sound of a room because no room is + + + align:start position:0% +sound of a room because no room is +silent. There's always things going on. + + align:start position:0% +silent. There's always things going on. + + + align:start position:0% +silent. There's always things going on. +The heat, ventilation, air conditioning, + + align:start position:0% +The heat, ventilation, air conditioning, + + + align:start position:0% +The heat, ventilation, air conditioning, +the out outside sound of the traffic. + + align:start position:0% +the out outside sound of the traffic. + + + align:start position:0% +the out outside sound of the traffic. +The word they use is ambience. A m i n + + align:start position:0% +The word they use is ambience. A m i n + + + align:start position:0% +The word they use is ambience. A m i n +ce or room tone. And so I'm interested, + + align:start position:0% +ce or room tone. And so I'm interested, + + + align:start position:0% +ce or room tone. And so I'm interested, +as you'll see, not only in what's + + align:start position:0% +as you'll see, not only in what's + + + align:start position:0% +as you'll see, not only in what's +ordinary visually, but what's ordinary + + align:start position:0% +ordinary visually, but what's ordinary + + + align:start position:0% +ordinary visually, but what's ordinary +sonically or + + align:start position:0% +sonically or + + + align:start position:0% +sonically or +orally. I also use the word + + align:start position:0% +orally. I also use the word + + + align:start position:0% +orally. I also use the word +choreography. And what I mean by that is + + align:start position:0% +choreography. And what I mean by that is + + + align:start position:0% +choreography. And what I mean by that is +the idea that people's motions, + + align:start position:0% +the idea that people's motions, + + + align:start position:0% +the idea that people's motions, +collective motions are coordinated. A + + align:start position:0% +collective motions are coordinated. A + + + align:start position:0% +collective motions are coordinated. A +factory depends on people working + + align:start position:0% +factory depends on people working + + + align:start position:0% +factory depends on people working +together. + + align:start position:0% + + + + align:start position:0% + +because if you don't do your part, the + + align:start position:0% +because if you don't do your part, the + + + align:start position:0% +because if you don't do your part, the +next guy can't do + + align:start position:0% +next guy can't do + + + align:start position:0% +next guy can't do +theirs. And so, one of the things I want + + align:start position:0% +theirs. And so, one of the things I want + + + align:start position:0% +theirs. And so, one of the things I want +to do is figure out how in the world to + + align:start position:0% +to do is figure out how in the world to + + + align:start position:0% +to do is figure out how in the world to +convey that choreography, which by the + + align:start position:0% +convey that choreography, which by the + + + align:start position:0% +convey that choreography, which by the +way is very difficult to do visually. + + align:start position:0% +way is very difficult to do visually. + + + align:start position:0% +way is very difficult to do visually. +And there are whole books devoted to how + + align:start position:0% +And there are whole books devoted to how + + + align:start position:0% +And there are whole books devoted to how +do you make visual representations of + + align:start position:0% +do you make visual representations of + + + align:start position:0% +do you make visual representations of +dance, you know, what are the right kind + + align:start position:0% +dance, you know, what are the right kind + + + align:start position:0% +dance, you know, what are the right kind +of photographs, what's the style to use + + align:start position:0% +of photographs, what's the style to use + + + align:start position:0% +of photographs, what's the style to use +and so forth. And there's people who + + align:start position:0% +and so forth. And there's people who + + + align:start position:0% +and so forth. And there's people who +worry about this a good deal in the + + align:start position:0% +worry about this a good deal in the + + + align:start position:0% +worry about this a good deal in the +dance business. The other theme is what + + align:start position:0% +dance business. The other theme is what + + + align:start position:0% +dance business. The other theme is what +I call the sensorium. What I mean is + + align:start position:0% +I call the sensorium. What I mean is + + + align:start position:0% +I call the sensorium. What I mean is +what is the experience of a place like? + + align:start position:0% +what is the experience of a place like? + + + align:start position:0% +what is the experience of a place like? +How do you record it? How do you record + + align:start position:0% +How do you record it? How do you record + + + align:start position:0% +How do you record it? How do you record +it archally so that 50 or 100 years ago, + + align:start position:0% +it archally so that 50 or 100 years ago, + + + align:start position:0% +it archally so that 50 or 100 years ago, +50 or 100 years from now, you have some + + align:start position:0% +50 or 100 years from now, you have some + + + align:start position:0% +50 or 100 years from now, you have some +idea of what it was, you know, what it + + align:start position:0% +idea of what it was, you know, what it + + + align:start position:0% +idea of what it was, you know, what it +felt like. um are probably we know the + + align:start position:0% +felt like. um are probably we know the + + + align:start position:0% +felt like. um are probably we know the +most about cities and what they were + + align:start position:0% +most about cities and what they were + + + align:start position:0% +most about cities and what they were +like from novels and visual uh I mean + + align:start position:0% +like from novels and visual uh I mean + + + align:start position:0% +like from novels and visual uh I mean +verbal descriptions certainly smells + + align:start position:0% +verbal descriptions certainly smells + + + align:start position:0% +verbal descriptions certainly smells +sounds and so + + align:start position:0% +sounds and so + + + align:start position:0% +sounds and so +forth and can we do and of course you + + align:start position:0% +forth and can we do and of course you + + + align:start position:0% +forth and can we do and of course you +know not everybody can be phobia but can + + align:start position:0% +know not everybody can be phobia but can + + + align:start position:0% +know not everybody can be phobia but can +we do interesting work without being + + align:start position:0% +we do interesting work without being + + + align:start position:0% +we do interesting work without being +great writers and that's an interesting + + align:start position:0% +great writers and that's an interesting + + + align:start position:0% +great writers and that's an interesting +question my second big thing besides the + + align:start position:0% +question my second big thing besides the + + + align:start position:0% +question my second big thing besides the +themes of repetition and the sensorium + + align:start position:0% +themes of repetition and the sensorium + + + align:start position:0% +themes of repetition and the sensorium +is that I take technology ology and I'll + + align:start position:0% +is that I take technology ology and I'll + + + align:start position:0% +is that I take technology ology and I'll +explain what I mean as the + + align:start position:0% +explain what I mean as the + + + align:start position:0% +explain what I mean as the +transcendental condition to use a + + align:start position:0% +transcendental condition to use a + + + align:start position:0% +transcendental condition to use a +content phrase for the work. In other + + align:start position:0% +content phrase for the work. In other + + + align:start position:0% +content phrase for the work. In other +words, it sets up the conditions for + + align:start position:0% +words, it sets up the conditions for + + + align:start position:0% +words, it sets up the conditions for +doing the work. So that if I use a wide + + align:start position:0% +doing the work. So that if I use a wide + + + align:start position:0% +doing the work. So that if I use a wide +angle lens or certain kind of color + + align:start position:0% +angle lens or certain kind of color + + + align:start position:0% +angle lens or certain kind of color +film, some things are possible, some + + align:start position:0% +film, some things are possible, some + + + align:start position:0% +film, some things are possible, some +things are not possible. You can always + + align:start position:0% +things are not possible. You can always + + + align:start position:0% +things are not possible. You can always +push the envelope, but you're always + + align:start position:0% +push the envelope, but you're always + + + align:start position:0% +push the envelope, but you're always +pushing an envelope given what's + + align:start position:0% +pushing an envelope given what's + + + align:start position:0% +pushing an envelope given what's +possible within a range. All right? Um + + align:start position:0% +possible within a range. All right? Um + + + align:start position:0% +possible within a range. All right? Um +and uh and that comes to me now that I'm + + align:start position:0% +and uh and that comes to me now that I'm + + + align:start position:0% +and uh and that comes to me now that I'm +beginning an oral documentation project + + align:start position:0% +beginning an oral documentation project + + + align:start position:0% +beginning an oral documentation project +where my knowledge of uh sound recording + + align:start position:0% +where my knowledge of uh sound recording + + + align:start position:0% +where my knowledge of uh sound recording +is very elementary compared to what I + + align:start position:0% +is very elementary compared to what I + + + align:start position:0% +is very elementary compared to what I +knew about photography when I started + + align:start position:0% +knew about photography when I started + + + align:start position:0% +knew about photography when I started +and I'm just encountering that. And the + + align:start position:0% +and I'm just encountering that. And the + + + align:start position:0% +and I'm just encountering that. And the +third theme in my work is what I call + + align:start position:0% +third theme in my work is what I call + + + align:start position:0% +third theme in my work is what I call +it's being social science informed. + + align:start position:0% +it's being social science informed. + + + align:start position:0% +it's being social science informed. +Uh, one of the problems of visual + + align:start position:0% +Uh, one of the problems of visual + + + align:start position:0% +Uh, one of the problems of visual +materials in the modern university is + + align:start position:0% +materials in the modern university is + + + align:start position:0% +materials in the modern university is +that if it ends up in the humanities + + align:start position:0% +that if it ends up in the humanities + + + align:start position:0% +that if it ends up in the humanities +hands, it can be like what the art + + align:start position:0% +hands, it can be like what the art + + + align:start position:0% +hands, it can be like what the art +historians do, which are careful + + align:start position:0% +historians do, which are careful + + + align:start position:0% +historians do, which are careful +description and and careful using of + + align:start position:0% +description and and careful using of + + + align:start position:0% +description and and careful using of +instances. But the social scientists in + + align:start position:0% +instances. But the social scientists in + + + align:start position:0% +instances. But the social scientists in +general do reductionist bits on it. + + align:start position:0% +general do reductionist bits on it. + + + align:start position:0% +general do reductionist bits on it. +They're always trying to say, well, you + + align:start position:0% +They're always trying to say, well, you + + + align:start position:0% +They're always trying to say, well, you +just how do you code the images? Or you, + + align:start position:0% +just how do you code the images? Or you, + + + align:start position:0% +just how do you code the images? Or you, +you know, if the anthropologists are so + + align:start position:0% +you know, if the anthropologists are so + + + align:start position:0% +you know, if the anthropologists are so +worried about the fact that visual + + align:start position:0% +worried about the fact that visual + + + align:start position:0% +worried about the fact that visual +anthropology is biased and prejudiced in + + align:start position:0% +anthropology is biased and prejudiced in + + + align:start position:0% +anthropology is biased and prejudiced in +various ways, you wonder why they do it + + align:start position:0% +various ways, you wonder why they do it + + + align:start position:0% +various ways, you wonder why they do it +at all. Um, and I want to talk about a + + align:start position:0% +at all. Um, and I want to talk about a + + + align:start position:0% +at all. Um, and I want to talk about a +way of thinking about this that I find + + align:start position:0% +way of thinking about this that I find + + + align:start position:0% +way of thinking about this that I find +valuable that doesn't that allows me to + + align:start position:0% +valuable that doesn't that allows me to + + + align:start position:0% +valuable that doesn't that allows me to +do my work and feel like I am being + + align:start position:0% +do my work and feel like I am being + + + align:start position:0% +do my work and feel like I am being +social scientific without being + + align:start position:0% +social scientific without being + + + align:start position:0% +social scientific without being +reductionist. And what I mean by + + align:start position:0% +reductionist. And what I mean by + + + align:start position:0% +reductionist. And what I mean by +reductionist is taking giving + + align:start position:0% +reductionist is taking giving + + + align:start position:0% +reductionist is taking giving +photographs or images less credence than + + align:start position:0% +photographs or images less credence than + + + align:start position:0% +photographs or images less credence than +verbal summaries thereof. All + + align:start position:0% +verbal summaries thereof. All + + + align:start position:0% +verbal summaries thereof. All +right. And remember we have a tremendous + + align:start position:0% +right. And remember we have a tremendous + + + align:start position:0% +right. And remember we have a tremendous +literature on nowadays of how ver visual + + align:start position:0% +literature on nowadays of how ver visual + + + align:start position:0% +literature on nowadays of how ver visual +images deceive us. And of course + + align:start position:0% +images deceive us. And of course + + + align:start position:0% +images deceive us. And of course +historically uh one of the great fields + + align:start position:0% +historically uh one of the great fields + + + align:start position:0% +historically uh one of the great fields +of intellectual inquiry was rhetoric and + + align:start position:0% +of intellectual inquiry was rhetoric and + + + align:start position:0% +of intellectual inquiry was rhetoric and +was all that was also about how verbal + + align:start position:0% +was all that was also about how verbal + + + align:start position:0% +was all that was also about how verbal +stuff deceive us. So why do people not + + align:start position:0% +stuff deceive us. So why do people not + + + align:start position:0% +stuff deceive us. So why do people not +talk? Why do people still make images? + + align:start position:0% +talk? Why do people still make images? + + + align:start position:0% +talk? Why do people still make images? +There's a reason I think I don't think + + align:start position:0% +There's a reason I think I don't think + + + align:start position:0% +There's a reason I think I don't think +we have to be uh uh + + align:start position:0% +we have to be uh uh + + + align:start position:0% +we have to be uh uh +paralyzed. All right, that's the general + + align:start position:0% +paralyzed. All right, that's the general + + + align:start position:0% +paralyzed. All right, that's the general +themes I'm going to be talking about. Um + + align:start position:0% +themes I'm going to be talking about. Um + + + align:start position:0% +themes I'm going to be talking about. Um +I am almost all my work can be described + + align:start position:0% +I am almost all my work can be described + + + align:start position:0% +I am almost all my work can be described +as by the way I will get to images + + align:start position:0% +as by the way I will get to images + + + align:start position:0% +as by the way I will get to images +shortly. So don't give up hope. Um + + align:start position:0% +shortly. So don't give up hope. Um + + + align:start position:0% +shortly. So don't give up hope. Um +almost all my work can be described as + + align:start position:0% +almost all my work can be described as + + + align:start position:0% +almost all my work can be described as +analytic description whether it be of + + align:start position:0% +analytic description whether it be of + + + align:start position:0% +analytic description whether it be of +math or physics of planning and design. + + align:start position:0% +math or physics of planning and design. + + + align:start position:0% +math or physics of planning and design. +I want to show the world to people who + + align:start position:0% +I want to show the world to people who + + + align:start position:0% +I want to show the world to people who +do it in such a way that it's + + align:start position:0% +do it in such a way that it's + + + align:start position:0% +do it in such a way that it's +recognizable to them but it's + + align:start position:0% +recognizable to them but it's + + + align:start position:0% +recognizable to them but it's +analytically described in a small number + + align:start position:0% +analytically described in a small number + + + align:start position:0% +analytically described in a small number +of categories and a collected leaked set + + align:start position:0% +of categories and a collected leaked set + + + align:start position:0% +of categories and a collected leaked set +of ideas. So that for example I wrote a + + align:start position:0% +of ideas. So that for example I wrote a + + + align:start position:0% +of ideas. So that for example I wrote a +book called uh on the physicist toolkit + + align:start position:0% +book called uh on the physicist toolkit + + + align:start position:0% +book called uh on the physicist toolkit +and the idea was could I set a small + + align:start position:0% +and the idea was could I set a small + + + align:start position:0% +and the idea was could I set a small +number of basic ideas that dominate how + + align:start position:0% +number of basic ideas that dominate how + + + align:start position:0% +number of basic ideas that dominate how +people do analysis or basic models and + + align:start position:0% +people do analysis or basic models and + + + align:start position:0% +people do analysis or basic models and +all I can ask from the scientist is yes + + align:start position:0% +all I can ask from the scientist is yes + + + align:start position:0% +all I can ask from the scientist is yes +that sounds right. Yeah. So what? Then + + align:start position:0% +that sounds right. Yeah. So what? Then + + + align:start position:0% +that sounds right. Yeah. So what? Then +I've won the game. Why? Because I found + + align:start position:0% +I've won the game. Why? Because I found + + + align:start position:0% +I've won the game. Why? Because I found +a representation that they find + + align:start position:0% +a representation that they find + + + align:start position:0% +a representation that they find +believable. Now you could say, well, why + + align:start position:0% +believable. Now you could say, well, why + + + align:start position:0% +believable. Now you could say, well, why +should you give them authority about, + + align:start position:0% +should you give them authority about, + + + align:start position:0% +should you give them authority about, +you know, what physics is? Well, my idea + + align:start position:0% +you know, what physics is? Well, my idea + + + align:start position:0% +you know, what physics is? Well, my idea +is that if I can reproduce the world + + align:start position:0% +is that if I can reproduce the world + + + align:start position:0% +is that if I can reproduce the world +that they know and they recognize it, + + align:start position:0% +that they know and they recognize it, + + + align:start position:0% +that they know and they recognize it, +I've done pretty + + align:start position:0% +I've done pretty + + + align:start position:0% +I've done pretty +well. And the reason I say all these + + align:start position:0% +well. And the reason I say all these + + + align:start position:0% +well. And the reason I say all these +skeptical remarks is because I've + + align:start position:0% +skeptical remarks is because I've + + + align:start position:0% +skeptical remarks is because I've +encountered them over the years. Uh, and + + align:start position:0% +encountered them over the years. Uh, and + + + align:start position:0% +encountered them over the years. Uh, and +it's the bread and butter of social + + align:start position:0% +it's the bread and butter of social + + + align:start position:0% +it's the bread and butter of social +scientists and and academics to be + + align:start position:0% +scientists and and academics to be + + + align:start position:0% +scientists and and academics to be +skeptical. Uh, I could do it, I guess, + + align:start position:0% +skeptical. Uh, I could do it, I guess, + + + align:start position:0% +skeptical. Uh, I could do it, I guess, +as well as anybody, but it's not what my + + align:start position:0% +as well as anybody, but it's not what my + + + align:start position:0% +as well as anybody, but it's not what my +bread and butter is. Um, and what I want + + align:start position:0% +bread and butter is. Um, and what I want + + + align:start position:0% +bread and butter is. Um, and what I want +to do is give analytic description for + + align:start position:0% +to do is give analytic description for + + + align:start position:0% +to do is give analytic description for +the purposes here of what I call the + + align:start position:0% +the purposes here of what I call the + + + align:start position:0% +the purposes here of what I call the +drama of ordinary life, whether it be + + align:start position:0% +drama of ordinary life, whether it be + + + align:start position:0% +drama of ordinary life, whether it be +worship in a Pentecostal church, how + + align:start position:0% +worship in a Pentecostal church, how + + + align:start position:0% +worship in a Pentecostal church, how +factories are organized and how people + + align:start position:0% +factories are organized and how people + + + align:start position:0% +factories are organized and how people +work together. + + align:start position:0% +work together. + + + align:start position:0% +work together. +Uh, and also I want to talk how the + + align:start position:0% +Uh, and also I want to talk how the + + + align:start position:0% +Uh, and also I want to talk how the +built environment is mold mold and is + + align:start position:0% +built environment is mold mold and is + + + align:start position:0% +built environment is mold mold and is +molded by us. So, for example, most + + align:start position:0% +molded by us. So, for example, most + + + align:start position:0% +molded by us. So, for example, most +recently, uh we have uh a general count + + align:start position:0% +recently, uh we have uh a general count + + + align:start position:0% +recently, uh we have uh a general count +LA County General Hospital, which I + + align:start position:0% +LA County General Hospital, which I + + + align:start position:0% +LA County General Hospital, which I +think has been featured on TV shows for + + align:start position:0% +think has been featured on TV shows for + + + align:start position:0% +think has been featured on TV shows for +one of the TV series, but it's county is + + align:start position:0% +one of the TV series, but it's county is + + + align:start position:0% +one of the TV series, but it's county is +famous. It's a place you go to get lots + + align:start position:0% +famous. It's a place you go to get lots + + + align:start position:0% +famous. It's a place you go to get lots +of experience with gunshot wounds and so + + align:start position:0% +of experience with gunshot wounds and so + + + align:start position:0% +of experience with gunshot wounds and so +forth. And it's being closed down and a + + align:start position:0% +forth. And it's being closed down and a + + + align:start position:0% +forth. And it's being closed down and a +new hospital is being built because of + + align:start position:0% +new hospital is being built because of + + + align:start position:0% +new hospital is being built because of +earthquake and politics. And so, I + + align:start position:0% +earthquake and politics. And so, I + + + align:start position:0% +earthquake and politics. And so, I +recently got permission and went top to + + align:start position:0% +recently got permission and went top to + + + align:start position:0% +recently got permission and went top to +bottom photographing the hospital and + + align:start position:0% +bottom photographing the hospital and + + + align:start position:0% +bottom photographing the hospital and +people working there, not any of the + + align:start position:0% +people working there, not any of the + + + align:start position:0% +people working there, not any of the +patients because that would have been + + align:start position:0% +patients because that would have been + + + align:start position:0% +patients because that would have been +impossible. + + align:start position:0% +impossible. + + + align:start position:0% +impossible. +because it'd be interesting to ask how + + align:start position:0% +because it'd be interesting to ask how + + + align:start position:0% +because it'd be interesting to ask how +is the design of the place affect the + + align:start position:0% +is the design of the place affect the + + + align:start position:0% +is the design of the place affect the +coordination of people in it. And of + + align:start position:0% +coordination of people in it. And of + + + align:start position:0% +coordination of people in it. And of +course lot you could do lots of field + + align:start position:0% +course lot you could do lots of field + + + align:start position:0% +course lot you could do lots of field +work but one of the possibilities is + + align:start position:0% +work but one of the possibilities is + + + align:start position:0% +work but one of the possibilities is +just to do the photographs and I spent + + align:start position:0% +just to do the photographs and I spent + + + align:start position:0% +just to do the photographs and I spent +about three or four days literally going + + align:start position:0% +about three or four days literally going + + + align:start position:0% +about three or four days literally going +through the hospital with a + + align:start position:0% +through the hospital with a + + + align:start position:0% +through the hospital with a +guide. Now one question you might ask is + + align:start position:0% +guide. Now one question you might ask is + + + align:start position:0% +guide. Now one question you might ask is +why photographs? Why you are doing + + align:start position:0% +why photographs? Why you are doing + + + align:start position:0% +why photographs? Why you are doing +photographs when most of your career is + + align:start position:0% +photographs when most of your career is + + + align:start position:0% +photographs when most of your career is +writing fairly analytic books? I wrote + + align:start position:0% +writing fairly analytic books? I wrote + + + align:start position:0% +writing fairly analytic books? I wrote +four books on mathematical modeling + + align:start position:0% +four books on mathematical modeling + + + align:start position:0% +four books on mathematical modeling +including quite technical stuff on + + align:start position:0% +including quite technical stuff on + + + align:start position:0% +including quite technical stuff on +mathematics. Three books on planning and + + align:start position:0% +mathematics. Three books on planning and + + + align:start position:0% +mathematics. Three books on planning and +design theory where I use religion and + + align:start position:0% +design theory where I use religion and + + + align:start position:0% +design theory where I use religion and +phenomenology. Where do I get warrant to + + align:start position:0% +phenomenology. Where do I get warrant to + + + align:start position:0% +phenomenology. Where do I get warrant to +do this? Well, there are three reasons. + + align:start position:0% +do this? Well, there are three reasons. + + + align:start position:0% +do this? Well, there are three reasons. +One, I've had a long-standing interest + + align:start position:0% +One, I've had a long-standing interest + + + align:start position:0% +One, I've had a long-standing interest +in this and actually wrote about it. And + + align:start position:0% +in this and actually wrote about it. And + + + align:start position:0% +in this and actually wrote about it. And +in graduate school, for reasons which I + + align:start position:0% +in graduate school, for reasons which I + + + align:start position:0% +in graduate school, for reasons which I +can't recall, I ended up taking a course + + align:start position:0% +can't recall, I ended up taking a course + + + align:start position:0% +can't recall, I ended up taking a course +on social science uses of photography + + align:start position:0% +on social science uses of photography + + + align:start position:0% +on social science uses of photography +from a guy named Paul Buyers who was + + align:start position:0% +from a guy named Paul Buyers who was + + + align:start position:0% +from a guy named Paul Buyers who was +Margaret me's + + align:start position:0% +Margaret me's + + + align:start position:0% +Margaret me's +photographer. And Margaret me was very + + align:start position:0% +photographer. And Margaret me was very + + + align:start position:0% +photographer. And Margaret me was very +big on photographs, visual materials in + + align:start position:0% +big on photographs, visual materials in + + + align:start position:0% +big on photographs, visual materials in +social + + align:start position:0% +social + + + align:start position:0% +social +science. Second, what do you do after + + align:start position:0% +science. Second, what do you do after + + + align:start position:0% +science. Second, what do you do after +you write your big book in your 50s? + + align:start position:0% +you write your big book in your 50s? + + + align:start position:0% +you write your big book in your 50s? +Here I am. I write my big book. All + + align:start position:0% +Here I am. I write my big book. All + + + align:start position:0% +Here I am. I write my big book. All +right? You know, deepest, most + + align:start position:0% +right? You know, deepest, most + + + align:start position:0% +right? You know, deepest, most +difficult, kills you, right? Knocks you + + align:start position:0% +difficult, kills you, right? Knocks you + + + align:start position:0% +difficult, kills you, right? Knocks you +dead. It's not necessarily longest, + + align:start position:0% +dead. It's not necessarily longest, + + + align:start position:0% +dead. It's not necessarily longest, +though I think it was. Uh, it's called + + align:start position:0% +though I think it was. Uh, it's called + + + align:start position:0% +though I think it was. Uh, it's called +doing mathematics. And I barely get away + + align:start position:0% +doing mathematics. And I barely get away + + + align:start position:0% +doing mathematics. And I barely get away +with writing it in the sense that it's + + align:start position:0% +with writing it in the sense that it's + + + align:start position:0% +with writing it in the sense that it's +at the edge of what I understand. And do + + align:start position:0% +at the edge of what I understand. And do + + + align:start position:0% +at the edge of what I understand. And do +I want to write another one? And it's + + align:start position:0% +I want to write another one? And it's + + + align:start position:0% +I want to write another one? And it's +very interesting. I realized that I had + + align:start position:0% +very interesting. I realized that I had + + + align:start position:0% +very interesting. I realized that I had +nothing more to say or I mean I could + + align:start position:0% +nothing more to say or I mean I could + + + align:start position:0% +nothing more to say or I mean I could +have more to say but it wouldn't be much + + align:start position:0% +have more to say but it wouldn't be much + + + align:start position:0% +have more to say but it wouldn't be much +of an improvement. So in some sense I + + align:start position:0% +of an improvement. So in some sense I + + + align:start position:0% +of an improvement. So in some sense I +had room in my research + + align:start position:0% +had room in my research + + + align:start position:0% +had room in my research +portfolio. And thirdly we when I moved + + align:start position:0% +portfolio. And thirdly we when I moved + + + align:start position:0% +portfolio. And thirdly we when I moved +we moved into a new building uh five six + + align:start position:0% +we moved into a new building uh five six + + + align:start position:0% +we moved into a new building uh five six +seven years ago and it had a room called + + align:start position:0% +seven years ago and it had a room called + + + align:start position:0% +seven years ago and it had a room called +a gallery and I was put on the committee + + align:start position:0% +a gallery and I was put on the committee + + + align:start position:0% +a gallery and I was put on the committee +to figure out what to put in the + + align:start position:0% +to figure out what to put in the + + + align:start position:0% +to figure out what to put in the +gallery. Well you know what committees + + align:start position:0% +gallery. Well you know what committees + + + align:start position:0% +gallery. Well you know what committees +do? Nothing. So um I just figured I + + align:start position:0% +do? Nothing. So um I just figured I + + + align:start position:0% +do? Nothing. So um I just figured I +asked him well I can put up a show of + + align:start position:0% +asked him well I can put up a show of + + + align:start position:0% +asked him well I can put up a show of +this stuff and that stuff and so I + + align:start position:0% +this stuff and that stuff and so I + + + align:start position:0% +this stuff and that stuff and so I +became quotes curator though I didn't + + align:start position:0% +became quotes curator though I didn't + + + align:start position:0% +became quotes curator though I didn't +know that I just putting up kept putting + + align:start position:0% +know that I just putting up kept putting + + + align:start position:0% +know that I just putting up kept putting +up shows and my secret was I didn't ask + + align:start position:0% +up shows and my secret was I didn't ask + + + align:start position:0% +up shows and my secret was I didn't ask +for much money from my dean so no one + + align:start position:0% +for much money from my dean so no one + + + align:start position:0% +for much money from my dean so no one +controlled it you know the shows kept + + align:start position:0% +controlled it you know the shows kept + + + align:start position:0% +controlled it you know the shows kept +going up they may have been a little + + align:start position:0% +going up they may have been a little + + + align:start position:0% +going up they may have been a little +cheesy and how they things were stuck on + + align:start position:0% +cheesy and how they things were stuck on + + + align:start position:0% +cheesy and how they things were stuck on +the wall the posters didn't look + + align:start position:0% +the wall the posters didn't look + + + align:start position:0% +the wall the posters didn't look +gorgeous but there was a show three + + align:start position:0% +gorgeous but there was a show three + + + align:start position:0% +gorgeous but there was a show three +shows a year and it's been going on for + + align:start position:0% +shows a year and it's been going on for + + + align:start position:0% +shows a year and it's been going on for +five six years and eventually everybody + + align:start position:0% +five six years and eventually everybody + + + align:start position:0% +five six years and eventually everybody +thinks it's part of the + + align:start position:0% +thinks it's part of the + + + align:start position:0% +thinks it's part of the +furniture which is what I've done. Um, + + align:start position:0% +furniture which is what I've done. Um, + + + align:start position:0% +furniture which is what I've done. Um, +so what I did was about eight nine years + + align:start position:0% +so what I did was about eight nine years + + + align:start position:0% +so what I did was about eight nine years +ago I started gingerly and started + + align:start position:0% +ago I started gingerly and started + + + align:start position:0% +ago I started gingerly and started +taking + + align:start position:0% +taking + + + align:start position:0% +taking +photographs and what made it work was + + align:start position:0% +photographs and what made it work was + + + align:start position:0% +photographs and what made it work was +and this is the thing that seems to me + + align:start position:0% +and this is the thing that seems to me + + + align:start position:0% +and this is the thing that seems to me +the deep insight. A city is an archive + + align:start position:0% +the deep insight. A city is an archive + + + align:start position:0% +the deep insight. A city is an archive +of its + + align:start position:0% +of its + + + align:start position:0% +of its +past. Nothing goes away virtually. The + + align:start position:0% +past. Nothing goes away virtually. The + + + align:start position:0% +past. Nothing goes away virtually. The +physical infra the built infrastructure + + align:start position:0% +physical infra the built infrastructure + + + align:start position:0% +physical infra the built infrastructure +does not go away. You build it for 50 + + align:start position:0% +does not go away. You build it for 50 + + + align:start position:0% +does not go away. You build it for 50 +years it lasts much longer in general. + + align:start position:0% +years it lasts much longer in general. + + + align:start position:0% +years it lasts much longer in general. +Everybody says everything gets knocked + + align:start position:0% +Everybody says everything gets knocked + + + align:start position:0% +Everybody says everything gets knocked +down in Los Angeles. That's not + + align:start position:0% +down in Los Angeles. That's not + + + align:start position:0% +down in Los Angeles. That's not +true. It just isn't true. Everything, + + align:start position:0% +true. It just isn't true. Everything, + + + align:start position:0% +true. It just isn't true. Everything, +you know, essentially, for whatever + + align:start position:0% +you know, essentially, for whatever + + + align:start position:0% +you know, essentially, for whatever +reason, almost nothing gets knocked down + + align:start position:0% +reason, almost nothing gets knocked down + + + align:start position:0% +reason, almost nothing gets knocked down +compared to what gets renovated, + + align:start position:0% +compared to what gets renovated, + + + align:start position:0% +compared to what gets renovated, +repainted, redone. + + align:start position:0% +repainted, redone. + + + align:start position:0% +repainted, redone. +Um, I've been walking around Boston all + + align:start position:0% +Um, I've been walking around Boston all + + + align:start position:0% +Um, I've been walking around Boston all +day today. And what's really impressive + + align:start position:0% +day today. And what's really impressive + + + align:start position:0% +day today. And what's really impressive +is how much that's going on in in in + + align:start position:0% +is how much that's going on in in in + + + align:start position:0% +is how much that's going on in in in +Boston. I mean, much more than in LA, + + align:start position:0% +Boston. I mean, much more than in LA, + + + align:start position:0% +Boston. I mean, much more than in LA, +but you have more old infrastructure and + + align:start position:0% +but you have more old infrastructure and + + + align:start position:0% +but you have more old infrastructure and +old buildings and so forth. And I guess + + align:start position:0% +old buildings and so forth. And I guess + + + align:start position:0% +old buildings and so forth. And I guess +a deep need for condos. + + align:start position:0% +a deep need for condos. + + + align:start position:0% +a deep need for condos. +Uh and so if you go look at a city + + align:start position:0% +Uh and so if you go look at a city + + + align:start position:0% +Uh and so if you go look at a city +visually, you will see the historical + + align:start position:0% +visually, you will see the historical + + + align:start position:0% +visually, you will see the historical +layers right then and there. So it's + + align:start position:0% +layers right then and there. So it's + + + align:start position:0% +layers right then and there. So it's +enormously rich. In other words, it's + + align:start position:0% +enormously rich. In other words, it's + + + align:start position:0% +enormously rich. In other words, it's +sort of like doing um uh archaeology, + + align:start position:0% +sort of like doing um uh archaeology, + + + align:start position:0% +sort of like doing um uh archaeology, +but you don't have to dig very + + align:start position:0% +but you don't have to dig very + + + align:start position:0% +but you don't have to dig very +much. And you know, there's a field + + align:start position:0% +much. And you know, there's a field + + + align:start position:0% +much. And you know, there's a field +called industrial archaeology where + + align:start position:0% +called industrial archaeology where + + + align:start position:0% +called industrial archaeology where +they, you know, they try to figure out + + align:start position:0% +they, you know, they try to figure out + + + align:start position:0% +they, you know, they try to figure out +how a factory worked 100 years ago. + + align:start position:0% +how a factory worked 100 years ago. + + + align:start position:0% +how a factory worked 100 years ago. +Well, this is much like that except lots + + align:start position:0% +Well, this is much like that except lots + + + align:start position:0% +Well, this is much like that except lots +of things are just there on the surface + + align:start position:0% +of things are just there on the surface + + + align:start position:0% +of things are just there on the surface +and it's quite remarkable and I'll get + + align:start position:0% +and it's quite remarkable and I'll get + + + align:start position:0% +and it's quite remarkable and I'll get +to some examples. And also I could get + + align:start position:0% +to some examples. And also I could get + + + align:start position:0% +to some examples. And also I could get +away with doing this photography. For + + align:start position:0% +away with doing this photography. For + + + align:start position:0% +away with doing this photography. For +whatever reason, I was not + + align:start position:0% +whatever reason, I was not + + + align:start position:0% +whatever reason, I was not +obtrusive. I go there and I look like + + align:start position:0% +obtrusive. I go there and I look like + + + align:start position:0% +obtrusive. I go there and I look like +someone said, "Oh, there's that old man + + align:start position:0% +someone said, "Oh, there's that old man + + + align:start position:0% +someone said, "Oh, there's that old man +with a + + align:start position:0% +with a + + + align:start position:0% +with a +camera." And that's wonderful because + + align:start position:0% +camera." And that's wonderful because + + + align:start position:0% +camera." And that's wonderful because +that means they don't care about you. + + align:start position:0% +that means they don't care about you. + + + align:start position:0% +that means they don't care about you. +They don't think you're up to anything + + align:start position:0% +They don't think you're up to anything + + + align:start position:0% +They don't think you're up to anything +harmful for the most part. I would go in + + align:start position:0% +harmful for the most part. I would go in + + + align:start position:0% +harmful for the most part. I would go in +and I'd say to a factory owner, uh, + + align:start position:0% +and I'd say to a factory owner, uh, + + + align:start position:0% +and I'd say to a factory owner, uh, +could I'm professor from USC. I'm + + align:start position:0% +could I'm professor from USC. I'm + + + align:start position:0% +could I'm professor from USC. I'm +interested in developing an archive of + + align:start position:0% +interested in developing an archive of + + + align:start position:0% +interested in developing an archive of +industry in Los Angeles. It's for the + + align:start position:0% +industry in Los Angeles. It's for the + + + align:start position:0% +industry in Los Angeles. It's for the +libraries. At about onethird of the + + align:start position:0% +libraries. At about onethird of the + + + align:start position:0% +libraries. At about onethird of the +time, they say yes. Well, you know, if + + align:start position:0% +time, they say yes. Well, you know, if + + + align:start position:0% +time, they say yes. Well, you know, if +you hit have a hit rate of 1/3 or 1/5, + + align:start position:0% +you hit have a hit rate of 1/3 or 1/5, + + + align:start position:0% +you hit have a hit rate of 1/3 or 1/5, +you're in business because all you have + + align:start position:0% +you're in business because all you have + + + align:start position:0% +you're in business because all you have +to do is ask five people to get one yes. + + align:start position:0% +to do is ask five people to get one yes. + + + align:start position:0% +to do is ask five people to get one yes. +Of course, that's not true + + align:start position:0% +Of course, that's not true + + + align:start position:0% +Of course, that's not true +probabilistically, but there's something + + align:start position:0% +probabilistically, but there's something + + + align:start position:0% +probabilistically, but there's something +else. Uh but the point is that the hit + + align:start position:0% +else. Uh but the point is that the hit + + + align:start position:0% +else. Uh but the point is that the hit +rates are fairly + + align:start position:0% +rates are fairly + + + align:start position:0% +rates are fairly +high that the major thing you have to + + align:start position:0% +high that the major thing you have to + + + align:start position:0% +high that the major thing you have to +realize is most owners are never there + + align:start position:0% +realize is most owners are never there + + + align:start position:0% +realize is most owners are never there +till 11:00 in the morning. The owner is + + align:start position:0% +till 11:00 in the morning. The owner is + + + align:start position:0% +till 11:00 in the morning. The owner is +not here is the usual line if you go + + align:start position:0% +not here is the usual line if you go + + + align:start position:0% +not here is the usual line if you go +early. What owners are doing before 11 + + align:start position:0% +early. What owners are doing before 11 + + + align:start position:0% +early. What owners are doing before 11 +is something else. Um the other thing + + align:start position:0% +is something else. Um the other thing + + + align:start position:0% +is something else. Um the other thing +you have to realize is that because + + align:start position:0% +you have to realize is that because + + + align:start position:0% +you have to realize is that because +someone says no, you just go to the next + + align:start position:0% +someone says no, you just go to the next + + + align:start position:0% +someone says no, you just go to the next +place. You never ever worry about the + + align:start position:0% +place. You never ever worry about the + + + align:start position:0% +place. You never ever worry about the +people who say no. You could say, "Well, + + align:start position:0% +people who say no. You could say, "Well, + + + align:start position:0% +people who say no. You could say, "Well, +isn't aren't you don't you ever buy a + + align:start position:0% +isn't aren't you don't you ever buy a + + + align:start position:0% +isn't aren't you don't you ever buy a +sample?" The answer, I'm sure, is yes. + + align:start position:0% +sample?" The answer, I'm sure, is yes. + + + align:start position:0% +sample?" The answer, I'm sure, is yes. +But if I have enough of them, I figure + + align:start position:0% +But if I have enough of them, I figure + + + align:start position:0% +But if I have enough of them, I figure +the biases will get worked through. I'm + + align:start position:0% +the biases will get worked through. I'm + + + align:start position:0% +the biases will get worked through. I'm +sure the places where they're torturing + + align:start position:0% +sure the places where they're torturing + + + align:start position:0% +sure the places where they're torturing +people to work will not let me + + align:start position:0% +people to work will not let me + + + align:start position:0% +people to work will not let me +photograph. But I do not believe there + + align:start position:0% +photograph. But I do not believe there + + + align:start position:0% +photograph. But I do not believe there +are very many of them + + align:start position:0% +are very many of them + + + align:start position:0% +are very many of them +statistically because the places where + + align:start position:0% +statistically because the places where + + + align:start position:0% +statistically because the places where +they let me photograph do not look like + + align:start position:0% +they let me photograph do not look like + + + align:start position:0% +they let me photograph do not look like +heaven. Um, and the other thing it helps + + align:start position:0% +heaven. Um, and the other thing it helps + + + align:start position:0% +heaven. Um, and the other thing it helps +is that I'm dogged. I recommend it + + align:start position:0% +is that I'm dogged. I recommend it + + + align:start position:0% +is that I'm dogged. I recommend it +highly. I would go out every morning, + + align:start position:0% +highly. I would go out every morning, + + + align:start position:0% +highly. I would go out every morning, +three, four days a week and + + align:start position:0% +three, four days a week and + + + align:start position:0% +three, four days a week and +photograph. When I was photographing + + align:start position:0% +photograph. When I was photographing + + + align:start position:0% +photograph. When I was photographing +churches, I would go up and down the + + align:start position:0% +churches, I would go up and down the + + + align:start position:0% +churches, I would go up and down the +streets of Los Angeles and + + align:start position:0% +streets of Los Angeles and + + + align:start position:0% +streets of Los Angeles and +systematically go up and down the + + align:start position:0% +systematically go up and down the + + + align:start position:0% +systematically go up and down the +streets, you know, and you don't run out + + align:start position:0% +streets, you know, and you don't run out + + + align:start position:0% +streets, you know, and you don't run out +of them. And some days you have you hit + + align:start position:0% +of them. And some days you have you hit + + + align:start position:0% +of them. And some days you have you hit +pay dirt and someday you don't. But your + + align:start position:0% +pay dirt and someday you don't. But your + + + align:start position:0% +pay dirt and someday you don't. But your +secret is you keep doing it. And if you + + align:start position:0% +secret is you keep doing it. And if you + + + align:start position:0% +secret is you keep doing it. And if you +keep doing it, you'll beat + + align:start position:0% +keep doing it, you'll beat + + + align:start position:0% +keep doing it, you'll beat +everybody. And if you don't worry about + + align:start position:0% +everybody. And if you don't worry about + + + align:start position:0% +everybody. And if you don't worry about +your photographs being perfect, but + + align:start position:0% +your photographs being perfect, but + + + align:start position:0% +your photographs being perfect, but +making sure you just get decent images + + align:start position:0% +making sure you just get decent images + + + align:start position:0% +making sure you just get decent images +and you keep doing it so you're not + + align:start position:0% +and you keep doing it so you're not + + + align:start position:0% +and you keep doing it so you're not +sitting there + + align:start position:0% +sitting there + + + align:start position:0% +sitting there +agonizing, you know, and adjusting your + + align:start position:0% +agonizing, you know, and adjusting your + + + align:start position:0% +agonizing, you know, and adjusting your +this and that, you get it done. Um, and + + align:start position:0% +this and that, you get it done. Um, and + + + align:start position:0% +this and that, you get it done. Um, and +there are costs to my technique, but the + + align:start position:0% +there are costs to my technique, but the + + + align:start position:0% +there are costs to my technique, but the +advantage is it gets done and I'm big on + + align:start position:0% +advantage is it gets done and I'm big on + + + align:start position:0% +advantage is it gets done and I'm big on +that. Nothing is worth doing if you're + + align:start position:0% +that. Nothing is worth doing if you're + + + align:start position:0% +that. Nothing is worth doing if you're +not going to do it. At least so I + + align:start position:0% +not going to do it. At least so I + + + align:start position:0% +not going to do it. At least so I +believe. Anyway, let me show you some of + + align:start position:0% +believe. Anyway, let me show you some of + + + align:start position:0% +believe. Anyway, let me show you some of +the work I've worked on. Um, and so what + + align:start position:0% +the work I've worked on. Um, and so what + + + align:start position:0% +the work I've worked on. Um, and so what +happened is that I had the the + + align:start position:0% +happened is that I had the the + + + align:start position:0% +happened is that I had the the +doggginess. I had the fortune of not, + + align:start position:0% +doggginess. I had the fortune of not, + + + align:start position:0% +doggginess. I had the fortune of not, +you know, I mean some people I mean + + align:start position:0% +you know, I mean some people I mean + + + align:start position:0% +you know, I mean some people I mean +there's a guy named Ken Haymon who is 6' + + align:start position:0% +there's a guy named Ken Haymon who is 6' + + + align:start position:0% +there's a guy named Ken Haymon who is 6' +something big guy. He can fit into any + + align:start position:0% +something big guy. He can fit into any + + + align:start position:0% +something big guy. He can fit into any +corner. He does never seems to take up + + align:start position:0% +corner. He does never seems to take up + + + align:start position:0% +corner. He does never seems to take up +space, you know, probably twice my size. + + align:start position:0% +space, you know, probably twice my size. + + + align:start position:0% +space, you know, probably twice my size. +Other people, you know, just don't have + + align:start position:0% +Other people, you know, just don't have + + + align:start position:0% +Other people, you know, just don't have +the style or something. I have no idea + + align:start position:0% +the style or something. I have no idea + + + align:start position:0% +the style or something. I have no idea +why I get away with it. Um, I'm polite + + align:start position:0% +why I get away with it. Um, I'm polite + + + align:start position:0% +why I get away with it. Um, I'm polite +and so forth, but maybe anyone can do + + align:start position:0% +and so forth, but maybe anyone can do + + + align:start position:0% +and so forth, but maybe anyone can do +it. I recommend it highly to try. Uh, + + align:start position:0% +it. I recommend it highly to try. Uh, + + + align:start position:0% +it. I recommend it highly to try. Uh, +anyway, there are several important + + align:start position:0% +anyway, there are several important + + + align:start position:0% +anyway, there are several important +themes in the work I've done. I started + + align:start position:0% +themes in the work I've done. I started + + + align:start position:0% +themes in the work I've done. I started +out actually the first thing I started + + align:start position:0% +out actually the first thing I started + + + align:start position:0% +out actually the first thing I started +doing is in Beverly Hills where I live. + + align:start position:0% +doing is in Beverly Hills where I live. + + + align:start position:0% +doing is in Beverly Hills where I live. +The largest form of urban renewal in + + align:start position:0% +The largest form of urban renewal in + + + align:start position:0% +The largest form of urban renewal in +Beverly Hills is done by Persian + + align:start position:0% +Beverly Hills is done by Persian + + + align:start position:0% +Beverly Hills is done by Persian +immigrants who buy a property, knock it + + align:start position:0% +immigrants who buy a property, knock it + + + align:start position:0% +immigrants who buy a property, knock it +down, and put up what I call a Persian + + align:start position:0% +down, and put up what I call a Persian + + + align:start position:0% +down, and put up what I call a Persian +palace. A Persian palace is + + align:start position:0% +palace. A Persian palace is + + + align:start position:0% +palace. A Persian palace is +a a western design that's that's been + + align:start position:0% +a a western design that's that's been + + + align:start position:0% +a a western design that's that's been +translated to Tehran, modern section, + + align:start position:0% +translated to Tehran, modern section, + + + align:start position:0% +translated to Tehran, modern section, +and then when they come here, they want + + align:start position:0% +and then when they come here, they want + + + align:start position:0% +and then when they come here, they want +to put some version of it up. It always + + align:start position:0% +to put some version of it up. It always + + + align:start position:0% +to put some version of it up. It always +has lots of balconies, lots of columns. + + align:start position:0% +has lots of balconies, lots of columns. + + + align:start position:0% +has lots of balconies, lots of columns. +It has a window over the front which is + + align:start position:0% +It has a window over the front which is + + + align:start position:0% +It has a window over the front which is +sometimes with, you know, fancy glass. + + align:start position:0% +sometimes with, you know, fancy glass. + + + align:start position:0% +sometimes with, you know, fancy glass. +It's fills up the envelope. It's a a + + align:start position:0% +It's fills up the envelope. It's a a + + + align:start position:0% +It's fills up the envelope. It's a a +mansionette and there are lots of them. + + align:start position:0% +mansionette and there are lots of them. + + + align:start position:0% +mansionette and there are lots of them. +Now, Beverly Hills has is + + align:start position:0% +Now, Beverly Hills has is + + + align:start position:0% +Now, Beverly Hills has is +undistinguished architecture. So, people + + align:start position:0% +undistinguished architecture. So, people + + + align:start position:0% +undistinguished architecture. So, people +say, "Oh, it's destroying our our the + + align:start position:0% +say, "Oh, it's destroying our our the + + + align:start position:0% +say, "Oh, it's destroying our our the +quality of our architecture." And I + + align:start position:0% +quality of our architecture." And I + + + align:start position:0% +quality of our architecture." And I +consider that one of the uh canards of + + align:start position:0% +consider that one of the uh canards of + + + align:start position:0% +consider that one of the uh canards of +the lowest sort. Um the quality of + + align:start position:0% +the lowest sort. Um the quality of + + + align:start position:0% +the lowest sort. Um the quality of +architecture for the price of the house + + align:start position:0% +architecture for the price of the house + + + align:start position:0% +architecture for the price of the house +is probably lower than any place in the + + align:start position:0% +is probably lower than any place in the + + + align:start position:0% +is probably lower than any place in the +world. + + align:start position:0% +world. + + + align:start position:0% +world. +Um, it's not that it's bad. It's just + + align:start position:0% +Um, it's not that it's bad. It's just + + + align:start position:0% +Um, it's not that it's bad. It's just +undistinguished. It's not architecture. + + align:start position:0% +undistinguished. It's not architecture. + + + align:start position:0% +undistinguished. It's not architecture. +It's some sort of, you know, you wanted + + align:start position:0% +It's some sort of, you know, you wanted + + + align:start position:0% +It's some sort of, you know, you wanted +a some years Georgian was popular. All + + align:start position:0% +a some years Georgian was popular. All + + + align:start position:0% +a some years Georgian was popular. All +right. So, I started photographing the + + align:start position:0% +right. So, I started photographing the + + + align:start position:0% +right. So, I started photographing the +Persian palaces, as I called them, and I + + align:start position:0% +Persian palaces, as I called them, and I + + + align:start position:0% +Persian palaces, as I called them, and I +didn't like doing it after a while. I + + align:start position:0% +didn't like doing it after a while. I + + + align:start position:0% +didn't like doing it after a while. I +realized this is just too funny. I was + + align:start position:0% +realized this is just too funny. I was + + + align:start position:0% +realized this is just too funny. I was +making fun of people at some level, and + + align:start position:0% +making fun of people at some level, and + + + align:start position:0% +making fun of people at some level, and +I didn't like that. Um, and then I + + align:start position:0% +I didn't like that. Um, and then I + + + align:start position:0% +I didn't like that. Um, and then I +noticed I did some other things. And let + + align:start position:0% +noticed I did some other things. And let + + + align:start position:0% +noticed I did some other things. And let +me give you some examples. + + align:start position:0% + + + + align:start position:0% + +Um, let's + + align:start position:0% + + + + align:start position:0% + +see. Yes, this is nail + + align:start position:0% +see. Yes, this is nail + + + align:start position:0% +see. Yes, this is nail +parlors. Um, I'm convinced that in + + align:start position:0% +parlors. Um, I'm convinced that in + + + align:start position:0% +parlors. Um, I'm convinced that in +California and Los Angeles, more money + + align:start position:0% +California and Los Angeles, more money + + + align:start position:0% +California and Los Angeles, more money +is spent on keeping uh women's nails in + + align:start position:0% +is spent on keeping uh women's nails in + + + align:start position:0% +is spent on keeping uh women's nails in +shape than the budgets of most small + + align:start position:0% + + + + align:start position:0% + +countries. The nail polars are + + align:start position:0% +countries. The nail polars are + + + align:start position:0% +countries. The nail polars are +ubiquitous. They reflect the fact that + + align:start position:0% +ubiquitous. They reflect the fact that + + + align:start position:0% +ubiquitous. They reflect the fact that +and but it's not just that there's + + align:start position:0% +and but it's not just that there's + + + align:start position:0% +and but it's not just that there's +demand. There's a supply. You know who + + align:start position:0% +demand. There's a supply. You know who + + + align:start position:0% +demand. There's a supply. You know who +the the nail pol people who do the nail + + align:start position:0% +the the nail pol people who do the nail + + + align:start position:0% +the the nail pol people who do the nail +polish. They're mostly Vietnamese + + align:start position:0% +polish. They're mostly Vietnamese + + + align:start position:0% +polish. They're mostly Vietnamese +immigrants historic of late. I mean, I'm + + align:start position:0% +immigrants historic of late. I mean, I'm + + + align:start position:0% +immigrants historic of late. I mean, I'm +sure it's changing who could get into + + align:start position:0% +sure it's changing who could get into + + + align:start position:0% +sure it's changing who could get into +this field for some reason. They started + + align:start position:0% +this field for some reason. They started + + + align:start position:0% +this field for some reason. They started +and they get into it. And nail pol are + + align:start position:0% +and they get into it. And nail pol are + + + align:start position:0% +and they get into it. And nail pol are +everywhere. I don't know if that's true + + align:start position:0% +everywhere. I don't know if that's true + + + align:start position:0% +everywhere. I don't know if that's true +here, but where I am, they're + + align:start position:0% +here, but where I am, they're + + + align:start position:0% +here, but where I am, they're +everywhere. And so I started noticing + + align:start position:0% +everywhere. And so I started noticing + + + align:start position:0% +everywhere. And so I started noticing +them. And once you start noticing a few, + + align:start position:0% +them. And once you start noticing a few, + + + align:start position:0% +them. And once you start noticing a few, +you start seeing them everywhere. + + align:start position:0% +you start seeing them everywhere. + + + align:start position:0% +you start seeing them everywhere. +And that's the basic phenomenon in most + + align:start position:0% +And that's the basic phenomenon in most + + + align:start position:0% +And that's the basic phenomenon in most +of my work. I notice something and then + + align:start position:0% +of my work. I notice something and then + + + align:start position:0% +of my work. I notice something and then +when I open up my eyes, I just don't + + align:start position:0% +when I open up my eyes, I just don't + + + align:start position:0% +when I open up my eyes, I just don't +notice one. I notice hundreds. That's + + align:start position:0% +notice one. I notice hundreds. That's + + + align:start position:0% +notice one. I notice hundreds. That's +the deepest thing. So for example, + + align:start position:0% +the deepest thing. So for example, + + + align:start position:0% +the deepest thing. So for example, +um yes, these are houses, storefront + + align:start position:0% +um yes, these are houses, storefront + + + align:start position:0% +um yes, these are houses, storefront +houses of worship. Not all of them are + + align:start position:0% +houses of worship. Not all of them are + + + align:start position:0% +houses of worship. Not all of them are +storefront houses of worship. This is a + + align:start position:0% +storefront houses of worship. This is a + + + align:start position:0% +storefront houses of worship. This is a +first church of the Rasta for example + + align:start position:0% +first church of the Rasta for example + + + align:start position:0% +first church of the Rasta for example +here. Uh all right. And this is not + + align:start position:0% +here. Uh all right. And this is not + + + align:start position:0% +here. Uh all right. And this is not +really a a a church. I mean it's a + + align:start position:0% +really a a a church. I mean it's a + + + align:start position:0% +really a a a church. I mean it's a +market actually. Uh but the Jefferson + + align:start position:0% +market actually. Uh but the Jefferson + + + align:start position:0% +market actually. Uh but the Jefferson +Boulevard in fact once had plastic trees + + align:start position:0% +Boulevard in fact once had plastic trees + + + align:start position:0% +Boulevard in fact once had plastic trees +on it. Uh it's on the it's and let me + + align:start position:0% +on it. Uh it's on the it's and let me + + + align:start position:0% +on it. Uh it's on the it's and let me +just show you a typical these are not + + align:start position:0% +just show you a typical these are not + + + align:start position:0% +just show you a typical these are not +the most standard of the ones. Let me + + align:start position:0% +the most standard of the ones. Let me + + + align:start position:0% +the most standard of the ones. Let me +just see if I can find one. Yeah, this + + align:start position:0% +just see if I can find one. Yeah, this + + + align:start position:0% +just see if I can find one. Yeah, this +is you know a converted um movie theater + + align:start position:0% +is you know a converted um movie theater + + + align:start position:0% +is you know a converted um movie theater +and so forth. There are loads of them. + + align:start position:0% +and so forth. There are loads of them. + + + align:start position:0% +and so forth. There are loads of them. +And then I can show you some more um in + + align:start position:0% +And then I can show you some more um in + + + align:start position:0% +And then I can show you some more um in +a + + align:start position:0% + + + + align:start position:0% + +moment. Yes. Another thing is I started + + align:start position:0% +moment. Yes. Another thing is I started + + + align:start position:0% +moment. Yes. Another thing is I started +noticing uh Los Angeles, as you probably + + align:start position:0% +noticing uh Los Angeles, as you probably + + + align:start position:0% +noticing uh Los Angeles, as you probably +know, has one of the largest um + + align:start position:0% +know, has one of the largest um + + + align:start position:0% +know, has one of the largest um +municipal utilities in the United + + align:start position:0% +municipal utilities in the United + + + align:start position:0% +municipal utilities in the United +States, if not the largest, the + + align:start position:0% +States, if not the largest, the + + + align:start position:0% +States, if not the largest, the +Department of Water and Power of + + align:start position:0% +Department of Water and Power of + + + align:start position:0% +Department of Water and Power of +Chinatown fame. And it has everywhere, + + align:start position:0% +Chinatown fame. And it has everywhere, + + + align:start position:0% +Chinatown fame. And it has everywhere, +it's a monopoly. It was meant as a + + align:start position:0% +it's a monopoly. It was meant as a + + + align:start position:0% +it's a monopoly. It was meant as a +monopoly. Um it essentially scared out + + align:start position:0% +monopoly. Um it essentially scared out + + + align:start position:0% +monopoly. Um it essentially scared out +and bought out all the competitors in + + align:start position:0% +and bought out all the competitors in + + + align:start position:0% +and bought out all the competitors in +Los Angeles, uh so it could run the grid + + align:start position:0% +Los Angeles, uh so it could run the grid + + + align:start position:0% +Los Angeles, uh so it could run the grid +itself. and and so it has these + + align:start position:0% +itself. and and so it has these + + + align:start position:0% +itself. and and so it has these +electrical distribution stations which + + align:start position:0% +electrical distribution stations which + + + align:start position:0% +electrical distribution stations which +are places which take the voltage from a + + align:start position:0% +are places which take the voltage from a + + + align:start position:0% +are places which take the voltage from a +high voltage to say 4500 volts and then + + align:start position:0% +high voltage to say 4500 volts and then + + + align:start position:0% +high voltage to say 4500 volts and then +it's distributed around and lowered for + + align:start position:0% +it's distributed around and lowered for + + + align:start position:0% +it's distributed around and lowered for +your home use. All right and uh so it + + align:start position:0% +your home use. All right and uh so it + + + align:start position:0% +your home use. All right and uh so it +turns out there areund about 135 to 150 + + align:start position:0% +turns out there areund about 135 to 150 + + + align:start position:0% +turns out there areund about 135 to 150 +of these stations and so I visited them + + align:start position:0% +of these stations and so I visited them + + + align:start position:0% +of these stations and so I visited them +all. All right. Once I started noticing + + align:start position:0% +all. All right. Once I started noticing + + + align:start position:0% +all. All right. Once I started noticing +them, you see, and these are these are + + align:start position:0% +them, you see, and these are these are + + + align:start position:0% +them, you see, and these are these are +the first + + align:start position:0% +the first + + + align:start position:0% +the first +20. All right. And you know, like this + + align:start position:0% +20. All right. And you know, like this + + + align:start position:0% +20. All right. And you know, like this +one's a palace here. Can you see my If I + + align:start position:0% +one's a palace here. Can you see my If I + + + align:start position:0% +one's a palace here. Can you see my If I +do that, you see? Yes. All right. Some + + align:start position:0% +do that, you see? Yes. All right. Some + + + align:start position:0% +do that, you see? Yes. All right. Some +of them are undistinguished. Some of + + align:start position:0% +of them are undistinguished. Some of + + + align:start position:0% +of them are undistinguished. Some of +them are This one looks different + + align:start position:0% +them are This one looks different + + + align:start position:0% +them are This one looks different +because it was a different company that + + align:start position:0% +because it was a different company that + + + align:start position:0% +because it was a different company that +built + + align:start position:0% +built + + + align:start position:0% +built +it and it was LA Gas and Electric. And + + align:start position:0% +it and it was LA Gas and Electric. And + + + align:start position:0% +it and it was LA Gas and Electric. And +uh in 1937, they were forced to sell + + align:start position:0% +uh in 1937, they were forced to sell + + + align:start position:0% +uh in 1937, they were forced to sell +out. + + align:start position:0% + + + + align:start position:0% + +Um, but many of them look like these + + align:start position:0% +Um, but many of them look like these + + + align:start position:0% +Um, but many of them look like these +monument. They're monumental structures. + + align:start position:0% +monument. They're monumental structures. + + + align:start position:0% +monument. They're monumental structures. +Okay. And what happened is I started + + align:start position:0% +Okay. And what happened is I started + + + align:start position:0% +Okay. And what happened is I started +noticing them and I was fortunate, this + + align:start position:0% +noticing them and I was fortunate, this + + + align:start position:0% +noticing them and I was fortunate, this +was before 9/11, I could get a list of + + align:start position:0% +was before 9/11, I could get a list of + + + align:start position:0% +was before 9/11, I could get a list of +them all from the Department of Water + + align:start position:0% +them all from the Department of Water + + + align:start position:0% +them all from the Department of Water +and Power. I'm sure after 9/11 I could + + align:start position:0% +and Power. I'm sure after 9/11 I could + + + align:start position:0% +and Power. I'm sure after 9/11 I could +not have gotten it. And but I was + + align:start position:0% +not have gotten it. And but I was + + + align:start position:0% +not have gotten it. And but I was +fortunate the guy liked me so he was + + align:start position:0% +fortunate the guy liked me so he was + + + align:start position:0% +fortunate the guy liked me so he was +willing to let me see it informally the + + align:start position:0% +willing to let me see it informally the + + + align:start position:0% +willing to let me see it informally the +list. Um, and so I could they're all on + + align:start position:0% +list. Um, and so I could they're all on + + + align:start position:0% +list. Um, and so I could they're all on +the street. they're not hidden, but to + + align:start position:0% +the street. they're not hidden, but to + + + align:start position:0% +the street. they're not hidden, but to +have a nice convenient list. And so that + + align:start position:0% +have a nice convenient list. And so that + + + align:start position:0% +have a nice convenient list. And so that +involved literally visiting all over Los + + align:start position:0% +involved literally visiting all over Los + + + align:start position:0% +involved literally visiting all over Los +Angeles because they have to be in every + + align:start position:0% +Angeles because they have to be in every + + + align:start position:0% +Angeles because they have to be in every +neighborhood cuz their job is to apply + + align:start position:0% +neighborhood cuz their job is to apply + + + align:start position:0% +neighborhood cuz their job is to apply +power. So in some sense, if you visit + + align:start position:0% +power. So in some sense, if you visit + + + align:start position:0% +power. So in some sense, if you visit +every one of these, you visited almost + + align:start position:0% +every one of these, you visited almost + + + align:start position:0% +every one of these, you visited almost +every section of the city of + + align:start position:0% +every section of the city of + + + align:start position:0% +every section of the city of +necessity, which is sort of nice. + + align:start position:0% + + + + align:start position:0% + +Um I also did things like for example um + + align:start position:0% +Um I also did things like for example um + + + align:start position:0% +Um I also did things like for example um +let's see where is + + align:start position:0% + + + + align:start position:0% + +it? Yes. Uh this is not very clear + + align:start position:0% +it? Yes. Uh this is not very clear + + + align:start position:0% +it? Yes. Uh this is not very clear +unfortunately but what I did was I I + + align:start position:0% +unfortunately but what I did was I I + + + align:start position:0% +unfortunately but what I did was I I +started photographing industrial + + align:start position:0% +started photographing industrial + + + align:start position:0% +started photographing industrial +streetscapes. In other words, I would + + align:start position:0% +streetscapes. In other words, I would + + + align:start position:0% +streetscapes. In other words, I would +find industrial streets in Los Angeles + + align:start position:0% +find industrial streets in Los Angeles + + + align:start position:0% +find industrial streets in Los Angeles +and literally photograph every building + + align:start position:0% +and literally photograph every building + + + align:start position:0% +and literally photograph every building +on the + + align:start position:0% +on the + + + align:start position:0% +on the +street. Okay. And this is one street in + + align:start position:0% +street. Okay. And this is one street in + + + align:start position:0% +street. Okay. And this is one street in +um on uh Clarence Street actually, which + + align:start position:0% +um on uh Clarence Street actually, which + + + align:start position:0% +um on uh Clarence Street actually, which +is on the east side of the river in the + + align:start position:0% +is on the east side of the river in the + + + align:start position:0% +is on the east side of the river in the +flats. And over here, this market is + + align:start position:0% +flats. And over here, this market is + + + align:start position:0% +flats. And over here, this market is +where some guys got killed uh soon + + align:start position:0% +where some guys got killed uh soon + + + align:start position:0% +where some guys got killed uh soon +before. And people are always worried + + align:start position:0% +before. And people are always worried + + + align:start position:0% +before. And people are always worried +about my well-being, but I tell them, no + + align:start position:0% +about my well-being, but I tell them, no + + + align:start position:0% +about my well-being, but I tell them, no +one no one commits murder at 9:00 in the + + align:start position:0% +one no one commits murder at 9:00 in the + + + align:start position:0% +one no one commits murder at 9:00 in the +morning on a weekday. you know, there's + + align:start position:0% +morning on a weekday. you know, there's + + + align:start position:0% +morning on a weekday. you know, there's +no one out to do it. You know, the + + align:start position:0% +no one out to do it. You know, the + + + align:start position:0% +no one out to do it. You know, the +crooks are not there. But, uh, so this + + align:start position:0% +crooks are not there. But, uh, so this + + + align:start position:0% +crooks are not there. But, uh, so this +is one area where I went, you know, it + + align:start position:0% +is one area where I went, you know, it + + + align:start position:0% +is one area where I went, you know, it +it's a industrial area and I and the + + align:start position:0% +it's a industrial area and I and the + + + align:start position:0% +it's a industrial area and I and the +idea was to somehow capture that + + align:start position:0% +idea was to somehow capture that + + + align:start position:0% +idea was to somehow capture that +industrial streetscape for future + + align:start position:0% +industrial streetscape for future + + + align:start position:0% +industrial streetscape for future +use. + + align:start position:0% + + + + align:start position:0% + +Um, now what what informs all this work? + + align:start position:0% +Um, now what what informs all this work? + + + align:start position:0% +Um, now what what informs all this work? +the ideas of repetition that there's not + + align:start position:0% +the ideas of repetition that there's not + + + align:start position:0% +the ideas of repetition that there's not +just one of them but there are multiple + + align:start position:0% +just one of them but there are multiple + + + align:start position:0% +just one of them but there are multiple +and there are multiple for good reasons. + + align:start position:0% +and there are multiple for good reasons. + + + align:start position:0% +and there are multiple for good reasons. +There are multiple of these departments + + align:start position:0% +There are multiple of these departments + + + align:start position:0% +There are multiple of these departments +of water and power electrical + + align:start position:0% +of water and power electrical + + + align:start position:0% +of water and power electrical +distribution stations because they have + + align:start position:0% +distribution stations because they have + + + align:start position:0% +distribution stations because they have +natural + + align:start position:0% +natural + + + align:start position:0% +natural +sizes roughly. You can't make you know + + align:start position:0% +sizes roughly. You can't make you know + + + align:start position:0% +sizes roughly. You can't make you know +you you don't want to it's sort of the + + align:start position:0% +you you don't want to it's sort of the + + + align:start position:0% +you you don't want to it's sort of the +solving a networking problem where you + + align:start position:0% +solving a networking problem where you + + + align:start position:0% +solving a networking problem where you +want to break it down to smaller units + + align:start position:0% +want to break it down to smaller units + + + align:start position:0% +want to break it down to smaller units +but you don't want too much + + align:start position:0% +but you don't want too much + + + align:start position:0% +but you don't want too much +centralization. you have the right level + + align:start position:0% +centralization. you have the right level + + + align:start position:0% +centralization. you have the right level +of centralization and for the powered + + align:start position:0% +of centralization and for the powered + + + align:start position:0% +of centralization and for the powered +needs. Uh you have too many at the edges + + align:start position:0% +needs. Uh you have too many at the edges + + + align:start position:0% +needs. Uh you have too many at the edges +of Los Angeles at the edges of Los + + align:start position:0% +of Los Angeles at the edges of Los + + + align:start position:0% +of Los Angeles at the edges of Los +Angeles's uh boundaries. Why? Because + + align:start position:0% +Angeles's uh boundaries. Why? Because + + + align:start position:0% +Angeles's uh boundaries. Why? Because +they Los Angeles is a place that's been + + align:start position:0% +they Los Angeles is a place that's been + + + align:start position:0% +they Los Angeles is a place that's been +in the business of annexation for 100 + + align:start position:0% +in the business of annexation for 100 + + + align:start position:0% +in the business of annexation for 100 +years. And so people from Department of + + align:start position:0% +years. And so people from Department of + + + align:start position:0% +years. And so people from Department of +Water Power figure well we might annex + + align:start position:0% +Water Power figure well we might annex + + + align:start position:0% +Water Power figure well we might annex +there so we may as well put it closer to + + align:start position:0% +there so we may as well put it closer to + + + align:start position:0% +there so we may as well put it closer to +the edge. They stopped annexing at some + + align:start position:0% +the edge. They stopped annexing at some + + + align:start position:0% +the edge. They stopped annexing at some +point but that's why they're there. Um + + align:start position:0% +point but that's why they're there. Um + + + align:start position:0% +point but that's why they're there. Um +and for example the um the store houses + + align:start position:0% +and for example the um the store houses + + + align:start position:0% +and for example the um the store houses +of worship which I visited and I have + + align:start position:0% +of worship which I visited and I have + + + align:start position:0% +of worship which I visited and I have +about 800 of them. And the secret of + + align:start position:0% +about 800 of them. And the secret of + + + align:start position:0% +about 800 of them. And the secret of +that how do you get so many? You just go + + align:start position:0% +that how do you get so many? You just go + + + align:start position:0% +that how do you get so many? You just go +up and down streets and you keep doing + + align:start position:0% +up and down streets and you keep doing + + + align:start position:0% +up and down streets and you keep doing +it until you get sick of it. And you + + align:start position:0% +it until you get sick of it. And you + + + align:start position:0% +it until you get sick of it. And you +know if your stomach is good you keep + + align:start position:0% +know if your stomach is good you keep + + + align:start position:0% +know if your stomach is good you keep +doing it for a few months. And the trick + + align:start position:0% +doing it for a few months. And the trick + + + align:start position:0% +doing it for a few months. And the trick +there is the following. By the way + + align:start position:0% +there is the following. By the way + + + align:start position:0% +there is the following. By the way +everybody know today this month is the + + align:start position:0% +everybody know today this month is the + + + align:start position:0% +everybody know today this month is the +100th anniversary of Pentecostalism. + + align:start position:0% + + + + align:start position:0% + +Uh here's what happens. In 1906 in Los + + align:start position:0% +Uh here's what happens. In 1906 in Los + + + align:start position:0% +Uh here's what happens. In 1906 in Los +Angeles at the Isuza Street Mission, + + align:start position:0% +Angeles at the Isuza Street Mission, + + + align:start position:0% +Angeles at the Isuza Street Mission, +which is now in what we little + + align:start position:0% +which is now in what we little + + + align:start position:0% +which is now in what we little +Tokyo, there was a people started + + align:start position:0% +Tokyo, there was a people started + + + align:start position:0% +Tokyo, there was a people started +speaking in + + align:start position:0% +speaking in + + + align:start position:0% +speaking in +tongues. Now it turns out people have + + align:start position:0% +tongues. Now it turns out people have + + + align:start position:0% +tongues. Now it turns out people have +been speaking in tongues before this, + + align:start position:0% +been speaking in tongues before this, + + + align:start position:0% +been speaking in tongues before this, +well before this in other parts of the + + align:start position:0% +well before this in other parts of the + + + align:start position:0% +well before this in other parts of the +United States and the world. But this + + align:start position:0% +United States and the world. But this + + + align:start position:0% +United States and the world. But this +turns out to be the archetypal moment + + align:start position:0% +turns out to be the archetypal moment + + + align:start position:0% +turns out to be the archetypal moment +from which it + + align:start position:0% +from which it + + + align:start position:0% +from which it +spreads in April + + align:start position:0% +spreads in April + + + align:start position:0% +spreads in April +1906. and it's a source for what we call + + align:start position:0% +1906. and it's a source for what we call + + + align:start position:0% +1906. and it's a source for what we call +modern + + align:start position:0% + + + + align:start position:0% + +Pentecostalism. So, Los Angeles is the + + align:start position:0% +Pentecostalism. So, Los Angeles is the + + + align:start position:0% +Pentecostalism. So, Los Angeles is the +Jerusalem of + + align:start position:0% + + + + align:start position:0% + +Pentecostalism. And this and then the + + align:start position:0% +Pentecostalism. And this and then the + + + align:start position:0% +Pentecostalism. And this and then the +other thing that's very important is the + + align:start position:0% +other thing that's very important is the + + + align:start position:0% +other thing that's very important is the +great migrations up north from the south + + align:start position:0% +great migrations up north from the south + + + align:start position:0% +great migrations up north from the south +to the north which brings + + align:start position:0% +to the north which brings + + + align:start position:0% +to the north which brings +African-Americans and c on certain + + align:start position:0% +African-Americans and c on certain + + + align:start position:0% +African-Americans and c on certain +routes and so forth. The other thing + + align:start position:0% +routes and so forth. The other thing + + + align:start position:0% +routes and so forth. The other thing +that's crucial about the um storefront + + align:start position:0% +that's crucial about the um storefront + + + align:start position:0% +that's crucial about the um storefront +churches which is important to + + align:start position:0% +churches which is important to + + + align:start position:0% +churches which is important to +understand is where are they located? + + align:start position:0% +understand is where are they located? + + + align:start position:0% +understand is where are they located? +They're always located in storefronts, + + align:start position:0% +They're always located in storefronts, + + + align:start position:0% +They're always located in storefronts, +right? Well, people don't build + + align:start position:0% +right? Well, people don't build + + + align:start position:0% +right? Well, people don't build +storefronts for churches. They don't pay + + align:start position:0% +storefronts for churches. They don't pay + + + align:start position:0% +storefronts for churches. They don't pay +enough rent. They built them because if + + align:start position:0% +enough rent. They built them because if + + + align:start position:0% +enough rent. They built them because if +you had um trolley lines, people would + + align:start position:0% +you had um trolley lines, people would + + + align:start position:0% +you had um trolley lines, people would +get off the trolley lines and do some + + align:start position:0% +get off the trolley lines and do some + + + align:start position:0% +get off the trolley lines and do some +shopping on their way home or to and + + align:start position:0% +shopping on their way home or to and + + + align:start position:0% +shopping on their way home or to and +from. Well, the trolley lines eventually + + align:start position:0% +from. Well, the trolley lines eventually + + + align:start position:0% +from. Well, the trolley lines eventually +go. The storefronts are still + + align:start position:0% +go. The storefronts are still + + + align:start position:0% +go. The storefronts are still +there. Turns out, and then the + + align:start position:0% +there. Turns out, and then the + + + align:start position:0% +there. Turns out, and then the +neighborhood doesn't do too well. So the + + align:start position:0% +neighborhood doesn't do too well. So the + + + align:start position:0% +neighborhood doesn't do too well. So the +these the people who can afford you know + + align:start position:0% +these the people who can afford you know + + + align:start position:0% +these the people who can afford you know +who can rent them and there's obviously + + align:start position:0% +who can rent them and there's obviously + + + align:start position:0% +who can rent them and there's obviously +nothing better you can do with them. So + + align:start position:0% +nothing better you can do with them. So + + + align:start position:0% +nothing better you can do with them. So +you have large numbers of storefront + + align:start position:0% +you have large numbers of storefront + + + align:start position:0% +you have large numbers of storefront +churches. Uh most storefront churches + + align:start position:0% +churches. Uh most storefront churches + + + align:start position:0% +churches. Uh most storefront churches +are small you know 50 to 100 at most + + align:start position:0% +are small you know 50 to 100 at most + + + align:start position:0% +are small you know 50 to 100 at most +members. The mega churches are entirely + + align:start position:0% +members. The mega churches are entirely + + + align:start position:0% +members. The mega churches are entirely +different business. Uh I don't know what + + align:start position:0% +different business. Uh I don't know what + + + align:start position:0% +different business. Uh I don't know what +happens here but mega churches nowadays + + align:start position:0% +happens here but mega churches nowadays + + + align:start position:0% +happens here but mega churches nowadays +are occupying in you find them in + + align:start position:0% +are occupying in you find them in + + + align:start position:0% +are occupying in you find them in +industrial parks in Los Angeles. + + align:start position:0% +industrial parks in Los Angeles. + + + align:start position:0% +industrial parks in Los Angeles. +you know, they take over a building and + + align:start position:0% +you know, they take over a building and + + + align:start position:0% +you know, they take over a building and +suitably, you know, uh, relig relig + + align:start position:0% +suitably, you know, uh, relig relig + + + align:start position:0% +suitably, you know, uh, relig relig +sacralize it, but remember it's still a + + align:start position:0% +sacralize it, but remember it's still a + + + align:start position:0% +sacralize it, but remember it's still a +tiltup, right? And so there's an there's + + align:start position:0% +tiltup, right? And so there's an there's + + + align:start position:0% +tiltup, right? And so there's an there's +a long story and what I've done with + + align:start position:0% +a long story and what I've done with + + + align:start position:0% +a long story and what I've done with +that, for example, uh, is I try to look + + align:start position:0% +that, for example, uh, is I try to look + + + align:start position:0% +that, for example, uh, is I try to look +at the symbolic content. I look at the + + align:start position:0% +at the symbolic content. I look at the + + + align:start position:0% +at the symbolic content. I look at the +quotes from scripture that they all put + + align:start position:0% +quotes from scripture that they all put + + + align:start position:0% +quotes from scripture that they all put +on their thing. It's connected. Do you + + align:start position:0% +on their thing. It's connected. Do you + + + align:start position:0% +on their thing. It's connected. Do you +know why it's Pentecostalism? Because on + + align:start position:0% +know why it's Pentecostalism? Because on + + + align:start position:0% +know why it's Pentecostalism? Because on +Pentecost the apostles uh it's if you + + align:start position:0% +Pentecost the apostles uh it's if you + + + align:start position:0% +Pentecost the apostles uh it's if you +look in Acts there's a the apostles are + + align:start position:0% +look in Acts there's a the apostles are + + + align:start position:0% +look in Acts there's a the apostles are +start speaking in in uh in + + align:start position:0% +start speaking in in uh in + + + align:start position:0% +start speaking in in uh in +tongues and so these are the return of + + align:start position:0% +tongues and so these are the return of + + + align:start position:0% +tongues and so these are the return of +so the so Pentecostals think of + + align:start position:0% +so the so Pentecostals think of + + + align:start position:0% +so the so Pentecostals think of +themselves as essentially + + align:start position:0% +themselves as essentially + + + align:start position:0% +themselves as essentially +um as recurrences of the + + align:start position:0% +um as recurrences of the + + + align:start position:0% +um as recurrences of the +apostles and that's what's so + + align:start position:0% +apostles and that's what's so + + + align:start position:0% +apostles and that's what's so +interesting about + + align:start position:0% +interesting about + + + align:start position:0% +interesting about +it. Um, and so you can connect the + + align:start position:0% +it. Um, and so you can connect the + + + align:start position:0% +it. Um, and so you can connect the +locations of the places, how they're + + align:start position:0% +locations of the places, how they're + + + align:start position:0% +locations of the places, how they're +marked, what are the structures look + + align:start position:0% +marked, what are the structures look + + + align:start position:0% +marked, what are the structures look +like, what kinds of symbolic contents, + + align:start position:0% +like, what kinds of symbolic contents, + + + align:start position:0% +like, what kinds of symbolic contents, +why they're where they are, and who's + + align:start position:0% +why they're where they are, and who's + + + align:start position:0% +why they're where they are, and who's +going to them in a systematic way. And + + align:start position:0% +going to them in a systematic way. And + + + align:start position:0% +going to them in a systematic way. And +so what you see is not just hundreds of + + align:start position:0% +so what you see is not just hundreds of + + + align:start position:0% +so what you see is not just hundreds of +storefront churches, but storefront + + align:start position:0% +storefront churches, but storefront + + + align:start position:0% +storefront churches, but storefront +churches in certain parts of + + align:start position:0% +churches in certain parts of + + + align:start position:0% +churches in certain parts of +town. And they have reasons why the + + align:start position:0% +town. And they have reasons why the + + + align:start position:0% +town. And they have reasons why the +storefronts are now occupied by the + + align:start position:0% +storefronts are now occupied by the + + + align:start position:0% +storefronts are now occupied by the +churches rather than by + + align:start position:0% +churches rather than by + + + align:start position:0% +churches rather than by +bakeries or something else. + + align:start position:0% +bakeries or something else. + + + align:start position:0% +bakeries or something else. +So that's so that's the kind of thing + + align:start position:0% +So that's so that's the kind of thing + + + align:start position:0% +So that's so that's the kind of thing +you want to do. The same thing with the + + align:start position:0% +you want to do. The same thing with the + + + align:start position:0% +you want to do. The same thing with the +department of water power. You can start + + align:start position:0% +department of water power. You can start + + + align:start position:0% +department of water power. You can start +telling a whole story about the history + + align:start position:0% +telling a whole story about the history + + + align:start position:0% +telling a whole story about the history +of the architecture because at one times + + align:start position:0% +of the architecture because at one times + + + align:start position:0% +of the architecture because at one times +it looks monumental eventually it sort + + align:start position:0% +it looks monumental eventually it sort + + + align:start position:0% +it looks monumental eventually it sort +of becomes boring and dull and of late + + align:start position:0% +of becomes boring and dull and of late + + + align:start position:0% +of becomes boring and dull and of late +it's become + + align:start position:0% +it's become + + + align:start position:0% +it's become +handsome and it all to do with the + + align:start position:0% +handsome and it all to do with the + + + align:start position:0% +handsome and it all to do with the +nature of relationship of uh the city to + + align:start position:0% +nature of relationship of uh the city to + + + align:start position:0% +nature of relationship of uh the city to +the people who live there. + + align:start position:0% +the people who live there. + + + align:start position:0% +the people who live there. +Um, in other words, these photographs + + align:start position:0% +Um, in other words, these photographs + + + align:start position:0% +Um, in other words, these photographs +gives you a handle on much larger + + align:start position:0% +gives you a handle on much larger + + + align:start position:0% +gives you a handle on much larger +systemic factors once you start learning + + align:start position:0% +systemic factors once you start learning + + + align:start position:0% +systemic factors once you start learning +more about it. But of course, you have + + align:start position:0% +more about it. But of course, you have + + + align:start position:0% +more about it. But of course, you have +to start reading the history of + + align:start position:0% +to start reading the history of + + + align:start position:0% +to start reading the history of +Pentecostalism or start understanding uh + + align:start position:0% +Pentecostalism or start understanding uh + + + align:start position:0% +Pentecostalism or start understanding uh +the kind of stuff that your students at + + align:start position:0% +the kind of stuff that your students at + + + align:start position:0% +the kind of stuff that your students at +MIT would know. Well, actually, they + + align:start position:0% +MIT would know. Well, actually, they + + + align:start position:0% +MIT would know. Well, actually, they +don't know usually because they learn + + align:start position:0% +don't know usually because they learn + + + align:start position:0% +don't know usually because they learn +about micro electronics, not about power + + align:start position:0% +about micro electronics, not about power + + + align:start position:0% +about micro electronics, not about power +systems in general, but you know, would + + align:start position:0% +systems in general, but you know, would + + + align:start position:0% +systems in general, but you know, would +learn about how electrical systems might + + align:start position:0% +learn about how electrical systems might + + + align:start position:0% +learn about how electrical systems might +work. Um, and so forth. + + align:start position:0% +work. Um, and so forth. + + + align:start position:0% +work. Um, and so forth. +Uh, and so that's what makes it really + + align:start position:0% +Uh, and so that's what makes it really + + + align:start position:0% +Uh, and so that's what makes it really +worth doing is that you're not just + + align:start position:0% +worth doing is that you're not just + + + align:start position:0% +worth doing is that you're not just +finding casual images. You're also + + align:start position:0% +finding casual images. You're also + + + align:start position:0% +finding casual images. You're also +really getting a chance to uh plug into + + align:start position:0% +really getting a chance to uh plug into + + + align:start position:0% +really getting a chance to uh plug into +much larger + + align:start position:0% +much larger + + + align:start position:0% +much larger +stories. Now, you can say, do you need + + align:start position:0% +stories. Now, you can say, do you need + + + align:start position:0% +stories. Now, you can say, do you need +800? Wouldn't 600 be enough of the + + align:start position:0% +800? Wouldn't 600 be enough of the + + + align:start position:0% +800? Wouldn't 600 be enough of the +storefront churches? I don't know how + + align:start position:0% +storefront churches? I don't know how + + + align:start position:0% +storefront churches? I don't know how +many you need. Um, Leo Steinberg in a + + align:start position:0% +many you need. Um, Leo Steinberg in a + + + align:start position:0% +many you need. Um, Leo Steinberg in a +very different context, he's a very + + align:start position:0% +very different context, he's a very + + + align:start position:0% +very different context, he's a very +distinguished art historian said, for + + align:start position:0% +distinguished art historian said, for + + + align:start position:0% +distinguished art historian said, for +phenomena which people don't want to + + align:start position:0% +phenomena which people don't want to + + + align:start position:0% +phenomena which people don't want to +believe, no number is too few. Once they + + align:start position:0% +believe, no number is too few. Once they + + + align:start position:0% +believe, no number is too few. Once they +think they agree with you that this is + + align:start position:0% +think they agree with you that this is + + + align:start position:0% +think they agree with you that this is +re a real phenomenon, two or three is + + align:start position:0% +re a real phenomenon, two or three is + + + align:start position:0% +re a real phenomenon, two or three is +enough. So you owe because their + + align:start position:0% +enough. So you owe because their + + + align:start position:0% +enough. So you owe because their +skepticism says, "Oh, this can't be real + + align:start position:0% +skepticism says, "Oh, this can't be real + + + align:start position:0% +skepticism says, "Oh, this can't be real +what you're + + align:start position:0% +what you're + + + align:start position:0% +what you're +saying." You know, to take P treat + + align:start position:0% +saying." You know, to take P treat + + + align:start position:0% +saying." You know, to take P treat +Pentecostal church, these storefront + + align:start position:0% +Pentecostal church, these storefront + + + align:start position:0% +Pentecostal church, these storefront +churches like you would + + align:start position:0% +churches like you would + + + align:start position:0% +churches like you would +treat interpreting its content and so + + align:start position:0% +treat interpreting its content and so + + + align:start position:0% +treat interpreting its content and so +forth. Oh, come on. So, you have to keep + + align:start position:0% +forth. Oh, come on. So, you have to keep + + + align:start position:0% +forth. Oh, come on. So, you have to keep +doing it. When they finally get it, they + + align:start position:0% +doing it. When they finally get it, they + + + align:start position:0% +doing it. When they finally get it, they +don't want to see anymore. So, the + + align:start position:0% +don't want to see anymore. So, the + + + align:start position:0% +don't want to see anymore. So, the +numbers are + + align:start position:0% +numbers are + + + align:start position:0% +numbers are +partially just sheer persistence and + + align:start position:0% +partially just sheer persistence and + + + align:start position:0% +partially just sheer persistence and +survey. partially if you had to bury + + align:start position:0% +survey. partially if you had to bury + + + align:start position:0% +survey. partially if you had to bury +people in the data so they can't that + + align:start position:0% +people in the data so they can't that + + + align:start position:0% +people in the data so they can't that +their ordinary skepticism has to be put + + align:start position:0% +their ordinary skepticism has to be put + + + align:start position:0% +their ordinary skepticism has to be put +aside. Uh they still can challenge you + + align:start position:0% +aside. Uh they still can challenge you + + + align:start position:0% +aside. Uh they still can challenge you +but they can't just say this is + + align:start position:0% +but they can't just say this is + + + align:start position:0% +but they can't just say this is +nonsense. + + align:start position:0% +nonsense. + + + align:start position:0% +nonsense. +Um + + align:start position:0% +Um + + + align:start position:0% +Um +and so it depends to do this kind of + + align:start position:0% +and so it depends to do this kind of + + + align:start position:0% +and so it depends to do this kind of +work you have to have a a wide range of + + align:start position:0% +work you have to have a a wide range of + + + align:start position:0% +work you have to have a a wide range of +knowledge which you have to pick up. I + + align:start position:0% +knowledge which you have to pick up. I + + + align:start position:0% +knowledge which you have to pick up. I +mean I did not uh come to this subject + + align:start position:0% +mean I did not uh come to this subject + + + align:start position:0% +mean I did not uh come to this subject +with a vast knowledge of Pentecostalism. + + align:start position:0% +with a vast knowledge of Pentecostalism. + + + align:start position:0% +with a vast knowledge of Pentecostalism. +uh but thank god there are very few + + align:start position:0% +uh but thank god there are very few + + + align:start position:0% +uh but thank god there are very few +books written on it compared to some + + align:start position:0% +books written on it compared to some + + + align:start position:0% +books written on it compared to some +other uh aspects of Christianity and so + + align:start position:0% +other uh aspects of Christianity and so + + + align:start position:0% +other uh aspects of Christianity and so +actually one can master the literature + + align:start position:0% +actually one can master the literature + + + align:start position:0% +actually one can master the literature +fairly quickly + + align:start position:0% +fairly quickly + + + align:start position:0% +fairly quickly +uh that's changing slowly but not as + + align:start position:0% +uh that's changing slowly but not as + + + align:start position:0% +uh that's changing slowly but not as +fast as you can keep up with it the + + align:start position:0% +fast as you can keep up with it the + + + align:start position:0% +fast as you can keep up with it the +second uh idea besides repetition is + + align:start position:0% +second uh idea besides repetition is + + + align:start position:0% +second uh idea besides repetition is +choreography what I want to do there is + + align:start position:0% +choreography what I want to do there is + + + align:start position:0% +choreography what I want to do there is +try to understand how complex systems of + + align:start position:0% +try to understand how complex systems of + + + align:start position:0% +try to understand how complex systems of +people and machinery and processes work + + align:start position:0% +people and machinery and processes work + + + align:start position:0% +people and machinery and processes work +together + + align:start position:0% +together + + + align:start position:0% +together +And that could be the flows of people + + align:start position:0% +And that could be the flows of people + + + align:start position:0% +And that could be the flows of people +and machinery and goods in a + + align:start position:0% +and machinery and goods in a + + + align:start position:0% +and machinery and goods in a +factory or uh the worship process in a + + align:start position:0% +factory or uh the worship process in a + + + align:start position:0% +factory or uh the worship process in a +church. In other words, it's different. + + align:start position:0% +church. In other words, it's different. + + + align:start position:0% +church. In other words, it's different. +It's one thing to take pictures of 800 + + align:start position:0% +It's one thing to take pictures of 800 + + + align:start position:0% +It's one thing to take pictures of 800 +churches facads. It's another to go into + + align:start position:0% +churches facads. It's another to go into + + + align:start position:0% +churches facads. It's another to go into +them and start + + align:start position:0% + + + + align:start position:0% + +photographing or making videos. And with + + align:start position:0% +photographing or making videos. And with + + + align:start position:0% +photographing or making videos. And with +the one thing you want to do when you go + + align:start position:0% +the one thing you want to do when you go + + + align:start position:0% +the one thing you want to do when you go +to these churches, you stop take + + align:start position:0% +to these churches, you stop take + + + align:start position:0% +to these churches, you stop take +pictures of people having transcendent + + align:start position:0% +pictures of people having transcendent + + + align:start position:0% +pictures of people having transcendent +experiences. you know, the eyes rolling + + align:start position:0% +experiences. you know, the eyes rolling + + + align:start position:0% +experiences. you know, the eyes rolling +back, all that stuff. You know, that's + + align:start position:0% +back, all that stuff. You know, that's + + + align:start position:0% +back, all that stuff. You know, that's +that's a sensationalism. Tom Roman + + align:start position:0% +that's a sensationalism. Tom Roman + + + align:start position:0% +that's a sensationalism. Tom Roman +specializes in that. Um, and other + + align:start position:0% +specializes in that. Um, and other + + + align:start position:0% +specializes in that. Um, and other +people do. What's really interesting is + + align:start position:0% +people do. What's really interesting is + + + align:start position:0% +people do. What's really interesting is +their ordinary sets of behaviors, how + + align:start position:0% +their ordinary sets of behaviors, how + + + align:start position:0% +their ordinary sets of behaviors, how +they're coordinated, how they work + + align:start position:0% +they're coordinated, how they work + + + align:start position:0% +they're coordinated, how they work +together. How in Pentecostalism in + + align:start position:0% +together. How in Pentecostalism in + + + align:start position:0% +together. How in Pentecostalism in +particular, which is supposed to not + + align:start position:0% +particular, which is supposed to not + + + align:start position:0% +particular, which is supposed to not +have an order of worship and everybody + + align:start position:0% +have an order of worship and everybody + + + align:start position:0% +have an order of worship and everybody +is to just feel it, everybody actually + + align:start position:0% +is to just feel it, everybody actually + + + align:start position:0% +is to just feel it, everybody actually +feels it, but they they're highly + + align:start position:0% +feels it, but they they're highly + + + align:start position:0% +feels it, but they they're highly +disciplined by the pastor and by the + + align:start position:0% +disciplined by the pastor and by the + + + align:start position:0% +disciplined by the pastor and by the +rules. In other words, even though it's + + align:start position:0% +rules. In other words, even though it's + + + align:start position:0% +rules. In other words, even though it's +supposed to be spontaneous, the + + align:start position:0% +supposed to be spontaneous, the + + + align:start position:0% +supposed to be spontaneous, the +spontaneity is highly disciplined and + + align:start position:0% +spontaneity is highly disciplined and + + + align:start position:0% +spontaneity is highly disciplined and +controlled, + + align:start position:0% +controlled, + + + align:start position:0% +controlled, +right? And so that choreography is what + + align:start position:0% +right? And so that choreography is what + + + align:start position:0% +right? And so that choreography is what +interests me. And how do you photograph + + align:start position:0% +interests me. And how do you photograph + + + align:start position:0% +interests me. And how do you photograph +that? And how do you get documentation + + align:start position:0% +that? And how do you get documentation + + + align:start position:0% +that? And how do you get documentation +that is very difficult and I've been + + align:start position:0% +that is very difficult and I've been + + + align:start position:0% +that is very difficult and I've been +trying to do it and I make no great + + align:start position:0% +trying to do it and I make no great + + + align:start position:0% +trying to do it and I make no great +claim there. + + align:start position:0% +claim there. + + + align:start position:0% +claim there. +My most wonderful thing that happened to + + align:start position:0% +My most wonderful thing that happened to + + + align:start position:0% +My most wonderful thing that happened to +me last week is I was down photographing + + align:start position:0% +me last week is I was down photographing + + + align:start position:0% +me last week is I was down photographing +I was going to photograph the moss in + + align:start position:0% +I was going to photograph the moss in + + + align:start position:0% +I was going to photograph the moss in +the cracks in the concrete because I was + + align:start position:0% +the cracks in the concrete because I was + + + align:start position:0% +the cracks in the concrete because I was +interested in in what kind of plants + + align:start position:0% +interested in in what kind of plants + + + align:start position:0% +interested in in what kind of plants +grow in a city that are + + align:start position:0% +grow in a city that are + + + align:start position:0% +grow in a city that are +inadvertent and there's I haven't been + + align:start position:0% +inadvertent and there's I haven't been + + + align:start position:0% +inadvertent and there's I haven't been +able to find the literature on this but + + align:start position:0% +able to find the literature on this but + + + align:start position:0% +able to find the literature on this but +I'm looking and I was down in in uh + + align:start position:0% +I'm looking and I was down in in uh + + + align:start position:0% +I'm looking and I was down in in uh +downtown Los Angeles in the industrial + + align:start position:0% +downtown Los Angeles in the industrial + + + align:start position:0% +downtown Los Angeles in the industrial +area which is sort of on the east side + + align:start position:0% +area which is sort of on the east side + + + align:start position:0% +area which is sort of on the east side +and um I didn't find that much + + align:start position:0% +and um I didn't find that much + + + align:start position:0% +and um I didn't find that much +interesting in a plant life but there + + align:start position:0% +interesting in a plant life but there + + + align:start position:0% +interesting in a plant life but there +was a there's a firm there called Brook + + align:start position:0% +was a there's a firm there called Brook + + + align:start position:0% +was a there's a firm there called Brook +Braid which I've been to once before, + + align:start position:0% +Braid which I've been to once before, + + + align:start position:0% +Braid which I've been to once before, +but the guy said, "We can't let you + + align:start position:0% +but the guy said, "We can't let you + + + align:start position:0% +but the guy said, "We can't let you +photograph now cuz we're having some + + align:start position:0% +photograph now cuz we're having some + + + align:start position:0% +photograph now cuz we're having some +legal problems." Um, and it's it's if + + align:start position:0% +legal problems." Um, and it's it's if + + + align:start position:0% +legal problems." Um, and it's it's if +you drive along the freeways in Los + + align:start position:0% +you drive along the freeways in Los + + + align:start position:0% +you drive along the freeways in Los +Angeles, their building stands out. You + + align:start position:0% +Angeles, their building stands out. You + + + align:start position:0% +Angeles, their building stands out. You +know, it's Brook and Hollywood narrow + + align:start position:0% +know, it's Brook and Hollywood narrow + + + align:start position:0% +know, it's Brook and Hollywood narrow +fabrics. Hollywood Hollywood brand + + align:start position:0% +fabrics. Hollywood Hollywood brand + + + align:start position:0% +fabrics. Hollywood Hollywood brand +fabrics are less fancy than Brookid + + align:start position:0% +fabrics are less fancy than Brookid + + + align:start position:0% +fabrics are less fancy than Brookid +fabrics. The same company, but it's two + + align:start position:0% +fabrics. The same company, but it's two + + + align:start position:0% +fabrics. The same company, but it's two +lines. So, anyway, I go in this time and + + align:start position:0% +lines. So, anyway, I go in this time and + + + align:start position:0% +lines. So, anyway, I go in this time and +the guy says, "Sure, we're selling, you + + align:start position:0% +the guy says, "Sure, we're selling, you + + + align:start position:0% +the guy says, "Sure, we're selling, you +know, I'll let you this time." So his + + align:start position:0% +know, I'll let you this time." So his + + + align:start position:0% +know, I'll let you this time." So his +son uh takes me around and it's filled + + align:start position:0% +son uh takes me around and it's filled + + + align:start position:0% +son uh takes me around and it's filled +with all these weaving + + align:start position:0% +with all these weaving + + + align:start position:0% +with all these weaving +machines with wood frames. They're all + + align:start position:0% +machines with wood frames. They're all + + + align:start position:0% +machines with wood frames. They're all +60 70 years old, 50 years old, often + + align:start position:0% +60 70 years old, 50 years old, often + + + align:start position:0% +60 70 years old, 50 years old, often +with power that comes from uh a rotating + + align:start position:0% +with power that comes from uh a rotating + + + align:start position:0% +with power that comes from uh a rotating +uh armature with with le with with + + align:start position:0% +uh armature with with le with with + + + align:start position:0% +uh armature with with le with with +leather + + align:start position:0% +leather + + + align:start position:0% +leather +belts. It was like and you see all these + + align:start position:0% +belts. It was like and you see all these + + + align:start position:0% +belts. It was like and you see all these +weaving machines. Anyway, that was my + + align:start position:0% +weaving machines. Anyway, that was my + + + align:start position:0% +weaving machines. Anyway, that was my +favorite thing of the last two weeks. + + align:start position:0% +favorite thing of the last two weeks. + + + align:start position:0% +favorite thing of the last two weeks. +And what you're trying to understand is + + align:start position:0% +And what you're trying to understand is + + + align:start position:0% +And what you're trying to understand is +the flows of people. And the big thing, + + align:start position:0% +the flows of people. And the big thing, + + + align:start position:0% +the flows of people. And the big thing, +by the way, of getting my chance to go + + align:start position:0% +by the way, of getting my chance to go + + + align:start position:0% +by the way, of getting my chance to go +inside industry is I never used a flash. + + align:start position:0% +inside industry is I never used a flash. + + + align:start position:0% +inside industry is I never used a flash. +I never used a + + align:start position:0% +I never used a + + + align:start position:0% +I never used a +tripod. In other words, I didn't + + align:start position:0% +tripod. In other words, I didn't + + + align:start position:0% +tripod. In other words, I didn't +interrupt + + align:start position:0% +interrupt + + + align:start position:0% +interrupt +them. I didn't tell people to pose for + + align:start position:0% +them. I didn't tell people to pose for + + + align:start position:0% +them. I didn't tell people to pose for +me. You might be able to do much + + align:start position:0% +me. You might be able to do much + + + align:start position:0% +me. You might be able to do much +more. All right. Lee Freedellander's + + align:start position:0% +more. All right. Lee Freedellander's + + + align:start position:0% +more. All right. Lee Freedellander's +omage book of at work is all images + + align:start position:0% +omage book of at work is all images + + + align:start position:0% +omage book of at work is all images +which were if not posed, you know, with + + align:start position:0% +which were if not posed, you know, with + + + align:start position:0% +which were if not posed, you know, with +flash and all that. But I wasn't invited + + align:start position:0% +flash and all that. But I wasn't invited + + + align:start position:0% +flash and all that. But I wasn't invited +in as a great photographer. And I + + align:start position:0% +in as a great photographer. And I + + + align:start position:0% +in as a great photographer. And I +figured that my whole idea was to get + + align:start position:0% +figured that my whole idea was to get + + + align:start position:0% +figured that my whole idea was to get +all my images before they decided to + + align:start position:0% +all my images before they decided to + + + align:start position:0% +all my images before they decided to +kick me + + align:start position:0% +kick me + + + align:start position:0% +kick me +out. + + align:start position:0% +out. + + + align:start position:0% +out. +Uh, and in the church thing, it's very + + align:start position:0% +Uh, and in the church thing, it's very + + + align:start position:0% +Uh, and in the church thing, it's very +interesting. I'm a Jew from Brooklyn, so + + align:start position:0% +interesting. I'm a Jew from Brooklyn, so + + + align:start position:0% +interesting. I'm a Jew from Brooklyn, so +you can imagine uh, you know, I'm not + + align:start position:0% +you can imagine uh, you know, I'm not + + + align:start position:0% +you can imagine uh, you know, I'm not +exactly about to be converted. And, uh, + + align:start position:0% +exactly about to be converted. And, uh, + + + align:start position:0% +exactly about to be converted. And, uh, +but it turns out uh, they're usually not + + align:start position:0% +but it turns out uh, they're usually not + + + align:start position:0% +but it turns out uh, they're usually not +interested. They'd like to know if + + align:start position:0% +interested. They'd like to know if + + + align:start position:0% +interested. They'd like to know if +you're religious a little bit, but they + + align:start position:0% +you're religious a little bit, but they + + + align:start position:0% +you're religious a little bit, but they +but I could go. Most of these places are + + align:start position:0% +but I could go. Most of these places are + + + align:start position:0% +but I could go. Most of these places are +quite willing to let me uh, photograph + + align:start position:0% +quite willing to let me uh, photograph + + + align:start position:0% +quite willing to let me uh, photograph +their service. + + align:start position:0% +their service. + + + align:start position:0% +their service. +Now, you know that many churches make + + align:start position:0% +Now, you know that many churches make + + + align:start position:0% +Now, you know that many churches make +DVDs uh and CDs of the uh minister's + + align:start position:0% +DVDs uh and CDs of the uh minister's + + + align:start position:0% +DVDs uh and CDs of the uh minister's +uh sermon so you can buy it on the way + + align:start position:0% +uh sermon so you can buy it on the way + + + align:start position:0% +uh sermon so you can buy it on the way +out. + + align:start position:0% +out. + + + align:start position:0% +out. +In fact, one of the big consumers of + + align:start position:0% +In fact, one of the big consumers of + + + align:start position:0% +In fact, one of the big consumers of +sound equipment are small + + align:start position:0% +sound equipment are small + + + align:start position:0% +sound equipment are small +churches, you know, with B with CD + + align:start position:0% +churches, you know, with B with CD + + + align:start position:0% +churches, you know, with B with CD +burners and the whole shebang because + + align:start position:0% +burners and the whole shebang because + + + align:start position:0% +burners and the whole shebang because +they, you know, you can get the you can + + align:start position:0% +they, you know, you can get the you can + + + align:start position:0% +they, you know, you can get the you can +buy and uh but this is different and + + align:start position:0% +buy and uh but this is different and + + + align:start position:0% +buy and uh but this is different and +they seem to be, you + + align:start position:0% +they seem to be, you + + + align:start position:0% +they seem to be, you +know, they were very they've been very + + align:start position:0% +know, they were very they've been very + + + align:start position:0% +know, they were very they've been very +open to it. Um, one of my students is a + + align:start position:0% +open to it. Um, one of my students is a + + + align:start position:0% +open to it. Um, one of my students is a +is a Pentecostal minister and so he he + + align:start position:0% +is a Pentecostal minister and so he he + + + align:start position:0% +is a Pentecostal minister and so he he +thinks the world of me, bless his soul, + + align:start position:0% +thinks the world of me, bless his soul, + + + align:start position:0% +thinks the world of me, bless his soul, +and so he said, "Sure." introduced me to + + align:start position:0% +and so he said, "Sure." introduced me to + + + align:start position:0% +and so he said, "Sure." introduced me to +the church. I I photographed and uh uh a + + align:start position:0% +the church. I I photographed and uh uh a + + + align:start position:0% +the church. I I photographed and uh uh a +ser his special service which went on + + align:start position:0% +ser his special service which went on + + + align:start position:0% +ser his special service which went on +for too many hours um for everybody. But + + align:start position:0% +for too many hours um for everybody. But + + + align:start position:0% +for too many hours um for everybody. But +it what I'm really telling you about is + + align:start position:0% +it what I'm really telling you about is + + + align:start position:0% +it what I'm really telling you about is +about access about those issues which + + align:start position:0% +about access about those issues which + + + align:start position:0% +about access about those issues which +are terribly terribly important because + + align:start position:0% +are terribly terribly important because + + + align:start position:0% +are terribly terribly important because +you're asking people to let you them + + align:start position:0% +you're asking people to let you them + + + align:start position:0% +you're asking people to let you them +into your most their most sacred places + + align:start position:0% +into your most their most sacred places + + + align:start position:0% +into your most their most sacred places +or their private lives. + + align:start position:0% + + + + align:start position:0% + +Um what I'm going to go on for another + + align:start position:0% +Um what I'm going to go on for another + + + align:start position:0% +Um what I'm going to go on for another +about 10 minutes. So I hope that's not + + align:start position:0% +about 10 minutes. So I hope that's not + + + align:start position:0% +about 10 minutes. So I hope that's not +too is that okay? Fine. Uh I want to + + align:start position:0% +too is that okay? Fine. Uh I want to + + + align:start position:0% +too is that okay? Fine. Uh I want to +talk about two other issues. Uh + + align:start position:0% +talk about two other issues. Uh + + + align:start position:0% +talk about two other issues. Uh +technology and finally what I call + + align:start position:0% +technology and finally what I call + + + align:start position:0% +technology and finally what I call +social science informed photo + + align:start position:0% +social science informed photo + + + align:start position:0% +social science informed photo +documentation. + + align:start position:0% + + + + align:start position:0% + +I'm fascinated about how the technology + + align:start position:0% +I'm fascinated about how the technology + + + align:start position:0% +I'm fascinated about how the technology +I use for photographing makes a + + align:start position:0% +I use for photographing makes a + + + align:start position:0% +I use for photographing makes a +difference. I'll admit I use + + align:start position:0% +difference. I'll admit I use + + + align:start position:0% +difference. I'll admit I use +film. I use transparency film. I do not + + align:start position:0% +film. I use transparency film. I do not + + + align:start position:0% +film. I use transparency film. I do not +use digital. If you want to have a long + + align:start position:0% +use digital. If you want to have a long + + + align:start position:0% +use digital. If you want to have a long +discussion about which is more archival. + + align:start position:0% +discussion about which is more archival. + + + align:start position:0% +discussion about which is more archival. +My attitude is film is wonderful because + + align:start position:0% +My attitude is film is wonderful because + + + align:start position:0% +My attitude is film is wonderful because +it sits there in the dark and if you + + align:start position:0% +it sits there in the dark and if you + + + align:start position:0% +it sits there in the dark and if you +don't get it wet and too hot, it'll be + + align:start position:0% +don't get it wet and too hot, it'll be + + + align:start position:0% +don't get it wet and too hot, it'll be +there in 50 years. I don't know what to + + align:start position:0% +there in 50 years. I don't know what to + + + align:start position:0% +there in 50 years. I don't know what to +do about digital right now. five years + + align:start position:0% +do about digital right now. five years + + + align:start position:0% +do about digital right now. five years +from now, maybe there'll be a better way + + align:start position:0% +from now, maybe there'll be a better way + + + align:start position:0% +from now, maybe there'll be a better way +of doing it, but I'm not going to worry. + + align:start position:0% +of doing it, but I'm not going to worry. + + + align:start position:0% +of doing it, but I'm not going to worry. +Um, but depending on the lens you use + + align:start position:0% +Um, but depending on the lens you use + + + align:start position:0% +Um, but depending on the lens you use +and so forth, you it's certain + + align:start position:0% +and so forth, you it's certain + + + align:start position:0% +and so forth, you it's certain +consequences. And I happen I discovered + + align:start position:0% +consequences. And I happen I discovered + + + align:start position:0% +consequences. And I happen I discovered +early on in my work that a wide angle + + align:start position:0% +early on in my work that a wide angle + + + align:start position:0% +early on in my work that a wide angle +lens is what I needed. I needed to stick + + align:start position:0% +lens is what I needed. I needed to stick + + + align:start position:0% +lens is what I needed. I needed to stick +my snout into the world and see it all. + + align:start position:0% +my snout into the world and see it all. + + + align:start position:0% +my snout into the world and see it all. +And that's what a wide angle allows you + + align:start position:0% +And that's what a wide angle allows you + + + align:start position:0% +And that's what a wide angle allows you +to do. You get very close, but you have + + align:start position:0% +to do. You get very close, but you have + + + align:start position:0% +to do. You get very close, but you have +a wide + + align:start position:0% +a wide + + + align:start position:0% +a wide +view so you can see context and detail. + + align:start position:0% + + + + align:start position:0% + +And also I didn't like the idea of using + + align:start position:0% +And also I didn't like the idea of using + + + align:start position:0% +And also I didn't like the idea of using +a telephoto lens because it made me feel + + align:start position:0% +a telephoto lens because it made me feel + + + align:start position:0% +a telephoto lens because it made me feel +like a voyer. I mean I'm a voyer clearly + + align:start position:0% +like a voyer. I mean I'm a voyer clearly + + + align:start position:0% +like a voyer. I mean I'm a voyer clearly +so that's not the point but it made me + + align:start position:0% +so that's not the point but it made me + + + align:start position:0% +so that's not the point but it made me +feel like a a dirty voyer. And um so uh + + align:start position:0% +feel like a a dirty voyer. And um so uh + + + align:start position:0% +feel like a a dirty voyer. And um so uh +I've ended up using you know film which + + align:start position:0% +I've ended up using you know film which + + + align:start position:0% +I've ended up using you know film which +has consequences in terms of its + + align:start position:0% +has consequences in terms of its + + + align:start position:0% +has consequences in terms of its +sensitivity and color faithfulness and + + align:start position:0% +sensitivity and color faithfulness and + + + align:start position:0% +sensitivity and color faithfulness and +so forth and wideangle lenses which have + + align:start position:0% +so forth and wideangle lenses which have + + + align:start position:0% +so forth and wideangle lenses which have +other consequences. And it turns out, + + align:start position:0% +other consequences. And it turns out, + + + align:start position:0% +other consequences. And it turns out, +for example, one of the things you want, + + align:start position:0% +for example, one of the things you want, + + + align:start position:0% +for example, one of the things you want, +which is not obvious, is you want really + + align:start position:0% +which is not obvious, is you want really + + + align:start position:0% +which is not obvious, is you want really +good lenses. Why? Not because it matters + + align:start position:0% +good lenses. Why? Not because it matters + + + align:start position:0% +good lenses. Why? Not because it matters +that much, except it might. Maybe + + align:start position:0% +that much, except it might. Maybe + + + align:start position:0% +that much, except it might. Maybe +there's something interesting in the + + align:start position:0% +there's something interesting in the + + + align:start position:0% +there's something interesting in the +corner of the image that someone in 50 + + align:start position:0% +corner of the image that someone in 50 + + + align:start position:0% +corner of the image that someone in 50 +years wants to un see and + + align:start position:0% +years wants to un see and + + + align:start position:0% +years wants to un see and +read. Only good lenses are good in the + + align:start position:0% +read. Only good lenses are good in the + + + align:start position:0% +read. Only good lenses are good in the +corners. Most lenses are superb in the + + align:start position:0% +corners. Most lenses are superb in the + + + align:start position:0% +corners. Most lenses are superb in the +center, but to get them good in the + + align:start position:0% +center, but to get them good in the + + + align:start position:0% +center, but to get them good in the +corners, you have to pay a lot of money. + + align:start position:0% +corners, you have to pay a lot of money. + + + align:start position:0% +corners, you have to pay a lot of money. +And most so-called consumer quality + + align:start position:0% +And most so-called consumer quality + + + align:start position:0% +And most so-called consumer quality +lenses are in fact not that good once + + align:start position:0% +lenses are in fact not that good once + + + align:start position:0% +lenses are in fact not that good once +they get to the edges. They fall off + + align:start position:0% +they get to the edges. They fall off + + + align:start position:0% +they get to the edges. They fall off +fairly well and no one + + align:start position:0% +fairly well and no one + + + align:start position:0% +fairly well and no one +cares. If you use documentation lenses, + + align:start position:0% +cares. If you use documentation lenses, + + + align:start position:0% +cares. If you use documentation lenses, +that's something else. But documentation + + align:start position:0% +that's something else. But documentation + + + align:start position:0% +that's something else. But documentation +lenses are not fast. There's lots of + + align:start position:0% +lenses are not fast. There's lots of + + + align:start position:0% +lenses are not fast. There's lots of +things wrong with + + align:start position:0% +things wrong with + + + align:start position:0% +things wrong with +them. And I'll give you two other + + align:start position:0% +them. And I'll give you two other + + + align:start position:0% +them. And I'll give you two other +examples. I I thought I would do some + + align:start position:0% +examples. I I thought I would do some + + + align:start position:0% +examples. I I thought I would do some +video work or at least film. And I tried + + align:start position:0% +video work or at least film. And I tried + + + align:start position:0% +video work or at least film. And I tried +first Super 8 and Kodakchrome uh which + + align:start position:0% +first Super 8 and Kodakchrome uh which + + + align:start position:0% +first Super 8 and Kodakchrome uh which +codchrome lasts forever. Uh, and Super 8 + + align:start position:0% +codchrome lasts forever. Uh, and Super 8 + + + align:start position:0% +codchrome lasts forever. Uh, and Super 8 +film is still made and Super Eight + + align:start position:0% +film is still made and Super Eight + + + align:start position:0% +film is still made and Super Eight +cameras can be bought on bought on eBay. + + align:start position:0% +cameras can be bought on bought on eBay. + + + align:start position:0% +cameras can be bought on bought on eBay. +Um, but the problem turned out to be the + + align:start position:0% +Um, but the problem turned out to be the + + + align:start position:0% +Um, but the problem turned out to be the +editing that I wasn't going to do the + + align:start position:0% +editing that I wasn't going to do the + + + align:start position:0% +editing that I wasn't going to do the +editing. It's just too much + + align:start position:0% +editing. It's just too much + + + align:start position:0% +editing. It's just too much +work and it was a bit expensive. So, I + + align:start position:0% +work and it was a bit expensive. So, I + + + align:start position:0% +work and it was a bit expensive. So, I +did go to digital + + align:start position:0% + + + + align:start position:0% + +video and digital video is easy to edit. + + align:start position:0% +video and digital video is easy to edit. + + + align:start position:0% +video and digital video is easy to edit. +iMovie does a fine job. Uh but of course + + align:start position:0% +iMovie does a fine job. Uh but of course + + + align:start position:0% +iMovie does a fine job. Uh but of course +using video is really hard and I think + + align:start position:0% +using video is really hard and I think + + + align:start position:0% +using video is really hard and I think +it's too hard for me to be honest but + + align:start position:0% +it's too hard for me to be honest but + + + align:start position:0% +it's too hard for me to be honest but +the there technology of digital made it + + align:start position:0% +the there technology of digital made it + + + align:start position:0% +the there technology of digital made it +possible for me to use it. My third + + align:start position:0% +possible for me to use it. My third + + + align:start position:0% +possible for me to use it. My third +example is my current project. About + + align:start position:0% +example is my current project. About + + + align:start position:0% +example is my current project. About +four months ago our provost I don't I + + align:start position:0% +four months ago our provost I don't I + + + align:start position:0% +four months ago our provost I don't I +don't know if MIT has this but our + + align:start position:0% +don't know if MIT has this but our + + + align:start position:0% +don't know if MIT has this but our +provost sends out initiatives for new + + align:start position:0% +provost sends out initiatives for new + + + align:start position:0% +provost sends out initiatives for new +ways of encouraging collaboration + + align:start position:0% +ways of encouraging collaboration + + + align:start position:0% +ways of encouraging collaboration +presumably bringing in more research + + align:start position:0% +presumably bringing in more research + + + align:start position:0% +presumably bringing in more research +grants and making university better. Um, + + align:start position:0% +grants and making university better. Um, + + + align:start position:0% +grants and making university better. Um, +and they come out fairly often and most + + align:start position:0% +and they come out fairly often and most + + + align:start position:0% +and they come out fairly often and most +of the time should be ignored from my + + align:start position:0% +of the time should be ignored from my + + + align:start position:0% +of the time should be ignored from my +point of view because they're just + + align:start position:0% +point of view because they're just + + + align:start position:0% +point of view because they're just +distracting. But there was one about the + + align:start position:0% +distracting. But there was one about the + + + align:start position:0% +distracting. But there was one about the +arts and the humanities and I was + + align:start position:0% +arts and the humanities and I was + + + align:start position:0% +arts and the humanities and I was +invited to the meeting about it and I + + align:start position:0% +invited to the meeting about it and I + + + align:start position:0% +invited to the meeting about it and I +said, "Oh, I this I need like a hole in + + align:start position:0% +said, "Oh, I this I need like a hole in + + + align:start position:0% +said, "Oh, I this I need like a hole in +the head." But somehow getting invited + + align:start position:0% +the head." But somehow getting invited + + + align:start position:0% +the head." But somehow getting invited +means I usually say yes. So it turns out + + align:start position:0% +means I usually say yes. So it turns out + + + align:start position:0% +means I usually say yes. So it turns out +I mention at this meeting that I tried + + align:start position:0% +I mention at this meeting that I tried + + + align:start position:0% +I mention at this meeting that I tried +using audio and I can't make it, you + + align:start position:0% +using audio and I can't make it, you + + + align:start position:0% +using audio and I can't make it, you +know, I don't know what I'm doing. And + + align:start position:0% +know, I don't know what I'm doing. And + + + align:start position:0% +know, I don't know what I'm doing. And +that's because um even using D I just + + align:start position:0% +that's because um even using D I just + + + align:start position:0% +that's because um even using D I just +wasn't it wasn't the audio my recording + + align:start position:0% +wasn't it wasn't the audio my recording + + + align:start position:0% +wasn't it wasn't the audio my recording +was not very good. I was using miniis + + align:start position:0% +was not very good. I was using miniis + + + align:start position:0% +was not very good. I was using miniis +and so forth but it wasn't very good. + + align:start position:0% +and so forth but it wasn't very good. + + + align:start position:0% +and so forth but it wasn't very good. +And it turns out someone comes up to me + + align:start position:0% +And it turns out someone comes up to me + + + align:start position:0% +And it turns out someone comes up to me +at the break. Who is Mr. THX? The guy + + align:start position:0% +at the break. Who is Mr. THX? The guy + + + align:start position:0% +at the break. Who is Mr. THX? The guy +who invented THX Mr. 5.1 sound a guy + + align:start position:0% +who invented THX Mr. 5.1 sound a guy + + + align:start position:0% +who invented THX Mr. 5.1 sound a guy +named Tom Holman who's a a guru of this + + align:start position:0% +named Tom Holman who's a a guru of this + + + align:start position:0% +named Tom Holman who's a a guru of this +sort. He's a professor of film sound at + + align:start position:0% +sort. He's a professor of film sound at + + + align:start position:0% +sort. He's a professor of film sound at +USC. And he says here's I I could help + + align:start position:0% +USC. And he says here's I I could help + + + align:start position:0% +USC. And he says here's I I could help +you. And two few days later he sends me + + align:start position:0% +you. And two few days later he sends me + + + align:start position:0% +you. And two few days later he sends me +a memo. Here's what you need. Here's + + align:start position:0% +a memo. Here's what you need. Here's + + + align:start position:0% +a memo. Here's what you need. Here's +where how to do it. Um, and so that's my + + align:start position:0% +where how to do it. Um, and so that's my + + + align:start position:0% +where how to do it. Um, and so that's my +next big project. And why am I going to + + align:start position:0% +next big project. And why am I going to + + + align:start position:0% +next big project. And why am I going to +do it? Because first of all, I have Tom + + align:start position:0% +do it? Because first of all, I have Tom + + + align:start position:0% +do it? Because first of all, I have Tom +behind me, so he'll tell me what to do + + align:start position:0% +behind me, so he'll tell me what to do + + + align:start position:0% +behind me, so he'll tell me what to do +technically. And that involves things + + align:start position:0% +technically. And that involves things + + + align:start position:0% +technically. And that involves things +like advice, which microphone to buy. + + align:start position:0% +like advice, which microphone to buy. + + + align:start position:0% +like advice, which microphone to buy. +There are many more microphones than + + align:start position:0% +There are many more microphones than + + + align:start position:0% +There are many more microphones than +lenses. And I don't understand it all + + align:start position:0% +lenses. And I don't understand it all + + + align:start position:0% +lenses. And I don't understand it all +very well. So he recommends a $5,000 + + align:start position:0% +very well. So he recommends a $5,000 + + + align:start position:0% +very well. So he recommends a $5,000 +pair. And you know what am I going to + + align:start position:0% +pair. And you know what am I going to + + + align:start position:0% +pair. And you know what am I going to +say? Uh, you know, you go and you get + + align:start position:0% +say? Uh, you know, you go and you get + + + align:start position:0% +say? Uh, you know, you go and you get +that. and then a certain kind of + + align:start position:0% +that. and then a certain kind of + + + align:start position:0% +that. and then a certain kind of +recorder, you know, and you try to get a + + align:start position:0% +recorder, you know, and you try to get a + + + align:start position:0% +recorder, you know, and you try to get a +grant to, as he said, you have to shake + + align:start position:0% +grant to, as he said, you have to shake + + + align:start position:0% +grant to, as he said, you have to shake +the trees to get the money, but I don't + + align:start position:0% +the trees to get the money, but I don't + + + align:start position:0% +the trees to get the money, but I don't +mind shaking trees. And I got some + + align:start position:0% +mind shaking trees. And I got some + + + align:start position:0% +mind shaking trees. And I got some +money. Second of all, what is my goal? + + align:start position:0% +money. Second of all, what is my goal? + + + align:start position:0% +money. Second of all, what is my goal? +My goal is to do accurate and archable + + align:start position:0% +My goal is to do accurate and archable + + + align:start position:0% +My goal is to do accurate and archable +audio. Accurate, which means that people + + align:start position:0% +audio. Accurate, which means that people + + + align:start position:0% +audio. Accurate, which means that people +in 50 years from now can know how to + + align:start position:0% +in 50 years from now can know how to + + + align:start position:0% +in 50 years from now can know how to +reproduce it so it sounds right. The + + align:start position:0% +reproduce it so it sounds right. The + + + align:start position:0% +reproduce it so it sounds right. The +right volume levels, the right spatial + + align:start position:0% +right volume levels, the right spatial + + + align:start position:0% +right volume levels, the right spatial +things. In other words, you have to give + + align:start position:0% +things. In other words, you have to give + + + align:start position:0% +things. In other words, you have to give +it metadata and calibration. And that's + + align:start position:0% +it metadata and calibration. And that's + + + align:start position:0% +it metadata and calibration. And that's +never done in audio + + align:start position:0% +never done in audio + + + align:start position:0% +never done in audio +recording. In the sound recording, the + + align:start position:0% +recording. In the sound recording, the + + + align:start position:0% +recording. In the sound recording, the +sound libraries of the studios often do + + align:start position:0% +sound libraries of the studios often do + + + align:start position:0% +sound libraries of the studios often do +not identify the source of it because + + align:start position:0% +not identify the source of it because + + + align:start position:0% +not identify the source of it because +they want you to think generically. In + + align:start position:0% +they want you to think generically. In + + + align:start position:0% +they want you to think generically. In +other words, if this sound is taken in + + align:start position:0% +other words, if this sound is taken in + + + align:start position:0% +other words, if this sound is taken in +Los Angeles, maybe you can use it in + + align:start position:0% +Los Angeles, maybe you can use it in + + + align:start position:0% +Los Angeles, maybe you can use it in +Hong Kong + + align:start position:0% +Hong Kong + + + align:start position:0% +Hong Kong +anyway for Hong, you know, Hong Kong + + align:start position:0% +anyway for Hong, you know, Hong Kong + + + align:start position:0% +anyway for Hong, you know, Hong Kong +sound. And so, in fact, they hide the + + align:start position:0% +sound. And so, in fact, they hide the + + + align:start position:0% +sound. And so, in fact, they hide the +information + + align:start position:0% +information + + + align:start position:0% +information +deliberately. And most people who do + + align:start position:0% +deliberately. And most people who do + + + align:start position:0% +deliberately. And most people who do +sound art are not concerned about + + align:start position:0% +sound art are not concerned about + + + align:start position:0% +sound art are not concerned about +accuracy because they're using the sound + + align:start position:0% +accuracy because they're using the sound + + + align:start position:0% +accuracy because they're using the sound +to do certain kinds of wonderful things. + + align:start position:0% +to do certain kinds of wonderful things. + + + align:start position:0% +to do certain kinds of wonderful things. +So the idea of accuracy in fact turns + + align:start position:0% +So the idea of accuracy in fact turns + + + align:start position:0% +So the idea of accuracy in fact turns +out according to Tom and what I've been + + align:start position:0% +out according to Tom and what I've been + + + align:start position:0% +out according to Tom and what I've been +able to find not very given much + + align:start position:0% +able to find not very given much + + + align:start position:0% +able to find not very given much +energy. Even the people who worry about + + align:start position:0% +energy. Even the people who worry about + + + align:start position:0% +energy. Even the people who worry about +hi-fi don't really care because they're + + align:start position:0% +hi-fi don't really care because they're + + + align:start position:0% +hi-fi don't really care because they're +caring they're not really concerned + + align:start position:0% +caring they're not really concerned + + + align:start position:0% +caring they're not really concerned +about accuracy. They're interested in a + + align:start position:0% +about accuracy. They're interested in a + + + align:start position:0% +about accuracy. They're interested in a +certain semblance of a certain sort. + + align:start position:0% +certain semblance of a certain sort. + + + align:start position:0% +certain semblance of a certain sort. +Um and the other thing is + + align:start position:0% +Um and the other thing is + + + align:start position:0% +Um and the other thing is +archable. What way of storing it will be + + align:start position:0% +archable. What way of storing it will be + + + align:start position:0% +archable. What way of storing it will be +around for hundred + + align:start position:0% +around for hundred + + + align:start position:0% +around for hundred +years and how do you store it the best + + align:start position:0% +years and how do you store it the best + + + align:start position:0% +years and how do you store it the best +way you know and what's the you know you + + align:start position:0% +way you know and what's the you know you + + + align:start position:0% +way you know and what's the you know you +have and these are technical issues but + + align:start position:0% +have and these are technical issues but + + + align:start position:0% +have and these are technical issues but +they're generally not addressed. It + + align:start position:0% +they're generally not addressed. It + + + align:start position:0% +they're generally not addressed. It +turns + + align:start position:0% +turns + + + align:start position:0% +turns +out it turns out I didn't know it how + + align:start position:0% +out it turns out I didn't know it how + + + align:start position:0% +out it turns out I didn't know it how +much it's not turned out but you know + + align:start position:0% +much it's not turned out but you know + + + align:start position:0% +much it's not turned out but you know +it's required of figuring this out and + + align:start position:0% +it's required of figuring this out and + + + align:start position:0% +it's required of figuring this out and +the idea that we've decided is we want + + align:start position:0% +the idea that we've decided is we want + + + align:start position:0% +the idea that we've decided is we want +to give people a sense of being there + + align:start position:0% +to give people a sense of being there + + + align:start position:0% +to give people a sense of being there +whatever the sounds are but we're not + + align:start position:0% +whatever the sounds are but we're not + + + align:start position:0% +whatever the sounds are but we're not +going to worry about uh Tom has + + align:start position:0% +going to worry about uh Tom has + + + align:start position:0% +going to worry about uh Tom has +something called 10.2 sound which is + + align:start position:0% +something called 10.2 sound which is + + + align:start position:0% +something called 10.2 sound which is +double + + align:start position:0% +double + + + align:start position:0% +double +5.1 and involves don't worry it's DARPA + + align:start position:0% +5.1 and involves don't worry it's DARPA + + + align:start position:0% +5.1 and involves don't worry it's DARPA +pays for it um you know they're + + align:start position:0% +pays for it um you know they're + + + align:start position:0% +pays for it um you know they're +interested in simulating + + align:start position:0% +interested in simulating + + + align:start position:0% +interested in simulating +warfare and whatnot. And so there's + + align:start position:0% +warfare and whatnot. And so there's + + + align:start position:0% +warfare and whatnot. And so there's +people in the engineering school who + + align:start position:0% +people in the engineering school who + + + align:start position:0% +people in the engineering school who +worry about this. Uh and uh and I've + + align:start position:0% +worry about this. Uh and uh and I've + + + align:start position:0% +worry about this. Uh and uh and I've +been in rooms with this 10.2 sound. It's + + align:start position:0% +been in rooms with this 10.2 sound. It's + + + align:start position:0% +been in rooms with this 10.2 sound. It's +really quite + + align:start position:0% +really quite + + + align:start position:0% +really quite +spectacular. Uh and the way I've + + align:start position:0% +spectacular. Uh and the way I've + + + align:start position:0% +spectacular. Uh and the way I've +described this that work I want to + + align:start position:0% +described this that work I want to + + + align:start position:0% +described this that work I want to +record ambience as the technical term in + + align:start position:0% +record ambience as the technical term in + + + align:start position:0% +record ambience as the technical term in +the cinema is called the sounds you + + align:start position:0% +the cinema is called the sounds you + + + align:start position:0% +the cinema is called the sounds you +don't listen + + align:start position:0% +don't listen + + + align:start position:0% +don't listen +to because they're just there. You don't + + align:start position:0% +to because they're just there. You don't + + + align:start position:0% +to because they're just there. You don't +pay attention to them. + + align:start position:0% +pay attention to them. + + + align:start position:0% +pay attention to them. +uh street noise, apartment noise from + + align:start position:0% +uh street noise, apartment noise from + + + align:start position:0% +uh street noise, apartment noise from +your neighbors, uh impure sounds, for + + align:start position:0% +your neighbors, uh impure sounds, for + + + align:start position:0% +your neighbors, uh impure sounds, for +example, people talking over something + + align:start position:0% +example, people talking over something + + + align:start position:0% +example, people talking over something +else, uh boring long passages because + + align:start position:0% +else, uh boring long passages because + + + align:start position:0% +else, uh boring long passages because +life is lots of boring long passages of + + align:start position:0% +life is lots of boring long passages of + + + align:start position:0% +life is lots of boring long passages of +sound. And most people say, "All right, + + align:start position:0% +sound. And most people say, "All right, + + + align:start position:0% +sound. And most people say, "All right, +30 seconds, that's enough." But the + + align:start position:0% +30 seconds, that's enough." But the + + + align:start position:0% +30 seconds, that's enough." But the +whole idea of a boring long passage is + + align:start position:0% +whole idea of a boring long passage is + + + align:start position:0% +whole idea of a boring long passage is +very important as + + align:start position:0% +very important as + + + align:start position:0% +very important as +experienced. So that's the kind of stuff + + align:start position:0% +experienced. So that's the kind of stuff + + + align:start position:0% +experienced. So that's the kind of stuff +I'm up to. And I don't know what I'm + + align:start position:0% +I'm up to. And I don't know what I'm + + + align:start position:0% +I'm up to. And I don't know what I'm +doing, by the way, in since this is my + + align:start position:0% +doing, by the way, in since this is my + + + align:start position:0% +doing, by the way, in since this is my +specs. I've done I've rented equipment + + align:start position:0% +specs. I've done I've rented equipment + + + align:start position:0% +specs. I've done I've rented equipment +and tried it out. So I know I can do it. + + align:start position:0% +and tried it out. So I know I can do it. + + + align:start position:0% +and tried it out. So I know I can do it. +But ask me in a in six months when I've + + align:start position:0% +But ask me in a in six months when I've + + + align:start position:0% +But ask me in a in six months when I've +done it because I don't believe in + + align:start position:0% +done it because I don't believe in + + + align:start position:0% +done it because I don't believe in +promising + + align:start position:0% +promising + + + align:start position:0% +promising +um ex you know other than trying hard. + + align:start position:0% +um ex you know other than trying hard. + + + align:start position:0% +um ex you know other than trying hard. +Uh for those who are interested a + + align:start position:0% +Uh for those who are interested a + + + align:start position:0% +Uh for those who are interested a +fisheye lens has a very similar um + + align:start position:0% +fisheye lens has a very similar um + + + align:start position:0% +fisheye lens has a very similar um +acceptance as a cardioid + + align:start position:0% +acceptance as a cardioid + + + align:start position:0% +acceptance as a cardioid +microphone. In other words the fisheye + + align:start position:0% +microphone. In other words the fisheye + + + align:start position:0% +microphone. In other words the fisheye +lens the way it sees the world is very + + align:start position:0% +lens the way it sees the world is very + + + align:start position:0% +lens the way it sees the world is very +much like the cardio cardioid + + align:start position:0% +much like the cardio cardioid + + + align:start position:0% +much like the cardio cardioid +microphone hears the world. So you might + + align:start position:0% +microphone hears the world. So you might + + + align:start position:0% +microphone hears the world. So you might +even use the image to give some idea of + + align:start position:0% +even use the image to give some idea of + + + align:start position:0% +even use the image to give some idea of +what you're hearing. + + align:start position:0% +what you're hearing. + + + align:start position:0% +what you're hearing. +And what you have to do is you have to + + align:start position:0% +And what you have to do is you have to + + + align:start position:0% +And what you have to do is you have to +be calibrated which mean you have to + + align:start position:0% +be calibrated which mean you have to + + + align:start position:0% +be calibrated which mean you have to +calibrate the process so you know what's + + align:start position:0% +calibrate the process so you know what's + + + align:start position:0% +calibrate the process so you know what's +what those bits on the CD should be + + align:start position:0% +what those bits on the CD should be + + + align:start position:0% +what those bits on the CD should be +correspond to and it has to be slated to + + align:start position:0% +correspond to and it has to be slated to + + + align:start position:0% +correspond to and it has to be slated to +use the term of art from cinema and that + + align:start position:0% +use the term of art from cinema and that + + + align:start position:0% +use the term of art from cinema and that +means that it has to have the metadata + + align:start position:0% +means that it has to have the metadata + + + align:start position:0% +means that it has to have the metadata +built in and what I and finally you have + + align:start position:0% +built in and what I and finally you have + + + align:start position:0% +built in and what I and finally you have +to use the right kind of microphones. If + + align:start position:0% +to use the right kind of microphones. If + + + align:start position:0% +to use the right kind of microphones. If +you go look at a microphone catalog, + + align:start position:0% +you go look at a microphone catalog, + + + align:start position:0% +you go look at a microphone catalog, +microphones are sort of um like getting + + align:start position:0% +microphones are sort of um like getting + + + align:start position:0% +microphones are sort of um like getting +plastic surgery. It's not that you want + + align:start position:0% +plastic surgery. It's not that you want + + + align:start position:0% +plastic surgery. It's not that you want +to get the same look, you want to sound + + align:start position:0% +to get the same look, you want to sound + + + align:start position:0% +to get the same look, you want to sound +look certain way or sound a certain way. + + align:start position:0% +look certain way or sound a certain way. + + + align:start position:0% +look certain way or sound a certain way. +And they have all sorts of interesting + + align:start position:0% +And they have all sorts of interesting + + + align:start position:0% +And they have all sorts of interesting +um nonlinearities in effect. And a truly + + align:start position:0% +um nonlinearities in effect. And a truly + + + align:start position:0% +um nonlinearities in effect. And a truly +linear microphone is not necessarily + + align:start position:0% +linear microphone is not necessarily + + + align:start position:0% +linear microphone is not necessarily +what people want for most recording, it + + align:start position:0% +what people want for most recording, it + + + align:start position:0% +what people want for most recording, it +turns out. So you have to get the right + + align:start position:0% +turns out. So you have to get the right + + + align:start position:0% +turns out. So you have to get the right +kinds of + + align:start position:0% +kinds of + + + align:start position:0% +kinds of +microphones with high degrees of coding + + align:start position:0% +microphones with high degrees of coding + + + align:start position:0% +microphones with high degrees of coding +and skill. And what I call is + + align:start position:0% +and skill. And what I call is + + + align:start position:0% +and skill. And what I call is +anti-velva. Velva is a film which soups + + align:start position:0% +anti-velva. Velva is a film which soups + + + align:start position:0% +anti-velva. Velva is a film which soups +up color and contra um saturation + + align:start position:0% +up color and contra um saturation + + + align:start position:0% +up color and contra um saturation +enormously. And you want the reverse of + + align:start position:0% +enormously. And you want the reverse of + + + align:start position:0% +enormously. And you want the reverse of +that. You want a natural color. And by + + align:start position:0% +that. You want a natural color. And by + + + align:start position:0% +that. You want a natural color. And by +the way, there are very few films that + + align:start position:0% +the way, there are very few films that + + + align:start position:0% +the way, there are very few films that +you can buy which have anything close to + + align:start position:0% +you can buy which have anything close to + + + align:start position:0% +you can buy which have anything close to +natural color. Very few professional + + align:start position:0% +natural color. Very few professional + + + align:start position:0% +natural color. Very few professional +unprofessional almost all of them are + + align:start position:0% +unprofessional almost all of them are + + + align:start position:0% +unprofessional almost all of them are +souped one way or the other for various + + align:start position:0% +souped one way or the other for various + + + align:start position:0% +souped one way or the other for various +purposes. And even then it's very hard + + align:start position:0% +purposes. And even then it's very hard + + + align:start position:0% +purposes. And even then it's very hard +to get anything close to natural color. + + align:start position:0% +to get anything close to natural color. + + + align:start position:0% +to get anything close to natural color. +And I could go on about you know which + + align:start position:0% +And I could go on about you know which + + + align:start position:0% +And I could go on about you know which +kind of recording system for those who + + align:start position:0% +kind of recording system for those who + + + align:start position:0% +kind of recording system for those who +care you use midside technique and I can + + align:start position:0% +care you use midside technique and I can + + + align:start position:0% +care you use midside technique and I can +explain later. All right. So my point is + + align:start position:0% +explain later. All right. So my point is + + + align:start position:0% +explain later. All right. So my point is +that I'm getting involved in a field + + align:start position:0% +that I'm getting involved in a field + + + align:start position:0% +that I'm getting involved in a field +where the technology is much less + + align:start position:0% +where the technology is much less + + + align:start position:0% +where the technology is much less +obvious to me much more apparent about + + align:start position:0% +obvious to me much more apparent about + + + align:start position:0% +obvious to me much more apparent about +the choices I make and much more crucial + + align:start position:0% +the choices I make and much more crucial + + + align:start position:0% +the choices I make and much more crucial +to what I do if I want to get something + + align:start position:0% +to what I do if I want to get something + + + align:start position:0% +to what I do if I want to get something +accurate and + + align:start position:0% +accurate and + + + align:start position:0% +accurate and +archival. And that's a discovery I made. + + align:start position:0% +archival. And that's a discovery I made. + + + align:start position:0% +archival. And that's a discovery I made. +I mean, I knew I if I used really good + + align:start position:0% +I mean, I knew I if I used really good + + + align:start position:0% +I mean, I knew I if I used really good +lenses, I'd be okay. I mean, I didn't, + + align:start position:0% +lenses, I'd be okay. I mean, I didn't, + + + align:start position:0% +lenses, I'd be okay. I mean, I didn't, +you know, I figured that's about all I + + align:start position:0% +you know, I figured that's about all I + + + align:start position:0% +you know, I figured that's about all I +can hope for, but this is much + + align:start position:0% +can hope for, but this is much + + + align:start position:0% +can hope for, but this is much +harder. Finally, I want to say something + + align:start position:0% +harder. Finally, I want to say something + + + align:start position:0% +harder. Finally, I want to say something +about what I call social science + + align:start position:0% +about what I call social science + + + align:start position:0% +about what I call social science +informed photo documentation. + + align:start position:0% +informed photo documentation. + + + align:start position:0% +informed photo documentation. +Um if you read the literature on visual + + align:start position:0% +Um if you read the literature on visual + + + align:start position:0% +Um if you read the literature on visual +documentation for example um what's the + + align:start position:0% +documentation for example um what's the + + + align:start position:0% +documentation for example um what's the +journal uh from the society of visual + + align:start position:0% +journal uh from the society of visual + + + align:start position:0% +journal uh from the society of visual +visual anthropology review or um what's + + align:start position:0% +visual anthropology review or um what's + + + align:start position:0% +visual anthropology review or um what's +the sociological one called I forgot but + + align:start position:0% +the sociological one called I forgot but + + + align:start position:0% +the sociological one called I forgot but +there's one the sociologist run or the + + align:start position:0% +there's one the sociologist run or the + + + align:start position:0% +there's one the sociologist run or the +literature on visual stuff there's as I + + align:start position:0% +literature on visual stuff there's as I + + + align:start position:0% +literature on visual stuff there's as I +said there's all the skepticism and + + align:start position:0% +said there's all the skepticism and + + + align:start position:0% +said there's all the skepticism and +there's all this stuff about methodology + + align:start position:0% +there's all this stuff about methodology + + + align:start position:0% +there's all this stuff about methodology +you know the right qualitative methods + + align:start position:0% +you know the right qualitative methods + + + align:start position:0% +you know the right qualitative methods +and if anyone's had to teach a + + align:start position:0% +and if anyone's had to teach a + + + align:start position:0% +and if anyone's had to teach a +qualitative methods course and try to + + align:start position:0% +qualitative methods course and try to + + + align:start position:0% +qualitative methods course and try to +use visual + + align:start position:0% +use visual + + + align:start position:0% +use visual +I mean after you read the qual articles + + align:start position:0% +I mean after you read the qual articles + + + align:start position:0% +I mean after you read the qual articles +on qualitative methods about visual + + align:start position:0% +on qualitative methods about visual + + + align:start position:0% +on qualitative methods about visual +images I don't know why anybody would + + align:start position:0% +images I don't know why anybody would + + + align:start position:0% +images I don't know why anybody would +use them you know it sort of takes all + + align:start position:0% +use them you know it sort of takes all + + + align:start position:0% +use them you know it sort of takes all +the pleasure out of it and um so what I + + align:start position:0% +the pleasure out of it and um so what I + + + align:start position:0% +the pleasure out of it and um so what I +say is that my topics and understanding + + align:start position:0% +say is that my topics and understanding + + + align:start position:0% +say is that my topics and understanding +of how these systems + + align:start position:0% +of how these systems + + + align:start position:0% +of how these systems +work comes out of my understanding of + + align:start position:0% +work comes out of my understanding of + + + align:start position:0% +work comes out of my understanding of +how cities work or how industrial + + align:start position:0% +how cities work or how industrial + + + align:start position:0% +how cities work or how industrial +processes work. I'm fortunate that I + + align:start position:0% +processes work. I'm fortunate that I + + + align:start position:0% +processes work. I'm fortunate that I +have a historian of uh uh Greg Heis + + align:start position:0% +have a historian of uh uh Greg Heis + + + align:start position:0% +have a historian of uh uh Greg Heis +who's my neighbor my off next to my + + align:start position:0% +who's my neighbor my off next to my + + + align:start position:0% +who's my neighbor my off next to my +office and he's been writing about the + + align:start position:0% +office and he's been writing about the + + + align:start position:0% +office and he's been writing about the +history of industry in Los Angeles and + + align:start position:0% +history of industry in Los Angeles and + + + align:start position:0% +history of industry in Los Angeles and +more general the history of industry in + + align:start position:0% +more general the history of industry in + + + align:start position:0% +more general the history of industry in +cities and so I have this expert to + + align:start position:0% +cities and so I have this expert to + + + align:start position:0% +cities and so I have this expert to +consult with. I you know I walk in and + + align:start position:0% +consult with. I you know I walk in and + + + align:start position:0% +consult with. I you know I walk in and +say look what I found and he'll tell me + + align:start position:0% +say look what I found and he'll tell me + + + align:start position:0% +say look what I found and he'll tell me +what it means. Um and what I say in + + align:start position:0% +what it means. Um and what I say in + + + align:start position:0% +what it means. Um and what I say in +other words is that I'm not I don't have + + align:start position:0% +other words is that I'm not I don't have + + + align:start position:0% +other words is that I'm not I don't have +a methodology but I have a + + align:start position:0% +a methodology but I have a + + + align:start position:0% +a methodology but I have a +well-informed mode of inquiry with lots + + align:start position:0% +well-informed mode of inquiry with lots + + + align:start position:0% +well-informed mode of inquiry with lots +and lots of information. So, if I'm + + align:start position:0% +and lots of information. So, if I'm + + + align:start position:0% +and lots of information. So, if I'm +writing about uh as I told you before + + align:start position:0% +writing about uh as I told you before + + + align:start position:0% +writing about uh as I told you before +about the storefront churches, my secret + + align:start position:0% +about the storefront churches, my secret + + + align:start position:0% +about the storefront churches, my secret +is that I'm not just telling you cute + + align:start position:0% +is that I'm not just telling you cute + + + align:start position:0% +is that I'm not just telling you cute +remarks, but it's based on the scholarly + + align:start position:0% +remarks, but it's based on the scholarly + + + align:start position:0% +remarks, but it's based on the scholarly +literature. And the people who know + + align:start position:0% +literature. And the people who know + + + align:start position:0% +literature. And the people who know +about storefront churches will know that + + align:start position:0% +about storefront churches will know that + + + align:start position:0% +about storefront churches will know that +I'm not that stupid about it, right? I + + align:start position:0% +I'm not that stupid about it, right? I + + + align:start position:0% +I'm not that stupid about it, right? I +know the books. I know what the the main + + align:start position:0% +know the books. I know what the the main + + + align:start position:0% +know the books. I know what the the main +arguments are and so + + align:start position:0% +arguments are and so + + + align:start position:0% +arguments are and so +forth. + + align:start position:0% +forth. + + + align:start position:0% +forth. +Um there are two other things that I + + align:start position:0% +Um there are two other things that I + + + align:start position:0% +Um there are two other things that I +think import that I would like to say. I + + align:start position:0% +think import that I would like to say. I + + + align:start position:0% +think import that I would like to say. I +could not do this work if I didn't think + + align:start position:0% +could not do this work if I didn't think + + + align:start position:0% +could not do this work if I didn't think +there were people who did work like it + + align:start position:0% +there were people who did work like it + + + align:start position:0% +there were people who did work like it +who who are universally acknowledged. + + align:start position:0% +who who are universally acknowledged. + + + align:start position:0% +who who are universally acknowledged. +All right, let me give you some + + align:start position:0% + + + + align:start position:0% + +examples. This did go was the French + + align:start position:0% +examples. This did go was the French + + + align:start position:0% +examples. This did go was the French +philosopher or + + align:start position:0% + + + + align:start position:0% + +philosopher more or less put together + + align:start position:0% +philosopher more or less put together + + + align:start position:0% +philosopher more or less put together +the encyclopedia in 1760, the first + + align:start position:0% +the encyclopedia in 1760, the first + + + align:start position:0% +the encyclopedia in 1760, the first +modern encyclopedia. And you've probably + + align:start position:0% +modern encyclopedia. And you've probably + + + align:start position:0% +modern encyclopedia. And you've probably +seen images like this one or this one + + align:start position:0% +seen images like this one or this one + + + align:start position:0% +seen images like this one or this one +which are wood engravings from the the + + align:start position:0% +which are wood engravings from the the + + + align:start position:0% +which are wood engravings from the the +encyclopedia. Uh you can buy a whole two + + align:start position:0% +encyclopedia. Uh you can buy a whole two + + + align:start position:0% +encyclopedia. Uh you can buy a whole two +volumes of dover volumes of all the + + align:start position:0% +volumes of dover volumes of all the + + + align:start position:0% +volumes of dover volumes of all the +illustrations or many of them of various + + align:start position:0% +illustrations or many of them of various + + + align:start position:0% +illustrations or many of them of various +industrial processes. Uh I gather that + + align:start position:0% +industrial processes. Uh I gather that + + + align:start position:0% +industrial processes. Uh I gather that +uh dedo did a lot of field work himself + + align:start position:0% +uh dedo did a lot of field work himself + + + align:start position:0% +uh dedo did a lot of field work himself +but he also stole the images from Mayo + + align:start position:0% +but he also stole the images from Mayo + + + align:start position:0% +but he also stole the images from Mayo +Mir who was doing similar work. So + + align:start position:0% +Mir who was doing similar work. So + + + align:start position:0% +Mir who was doing similar work. So +there's some questions about who + + align:start position:0% +there's some questions about who + + + align:start position:0% +there's some questions about who +deserves all the credit. But uh the + + align:start position:0% +deserves all the credit. But uh the + + + align:start position:0% +deserves all the credit. But uh the +point is if you go look at this you see + + align:start position:0% +point is if you go look at this you see + + + align:start position:0% +point is if you go look at this you see +the details. I this morning I was in a + + align:start position:0% +the details. I this morning I was in a + + + align:start position:0% +the details. I this morning I was in a +place called Slade Gorton and company + + align:start position:0% +place called Slade Gorton and company + + + align:start position:0% +place called Slade Gorton and company +which is a fish company in um in uh New + + align:start position:0% +which is a fish company in um in uh New + + + align:start position:0% +which is a fish company in um in uh New +Market Square. And if you I was walked + + align:start position:0% +Market Square. And if you I was walked + + + align:start position:0% +Market Square. And if you I was walked +up the stairs and what did I see? I saw + + align:start position:0% +up the stairs and what did I see? I saw + + + align:start position:0% +up the stairs and what did I see? I saw +the engravings from Dro for making + + align:start position:0% +the engravings from Dro for making + + + align:start position:0% +the engravings from Dro for making +fishnetss. + + align:start position:0% + + + + align:start position:0% + +Amazing. Say to me the second person who + + align:start position:0% +Amazing. Say to me the second person who + + + align:start position:0% +Amazing. Say to me the second person who +gives me courage. So DO does all of this + + align:start position:0% +gives me courage. So DO does all of this + + + align:start position:0% +gives me courage. So DO does all of this +stuff about industry. So if I want to + + align:start position:0% +stuff about industry. So if I want to + + + align:start position:0% +stuff about industry. So if I want to +describe how industry is done, I'm not + + align:start position:0% +describe how industry is done, I'm not + + + align:start position:0% +describe how industry is done, I'm not +alone. And DO is the best representative + + align:start position:0% +alone. And DO is the best representative + + + align:start position:0% +alone. And DO is the best representative +I know cuz most industrial photography + + align:start position:0% +I know cuz most industrial photography + + + align:start position:0% +I know cuz most industrial photography +is either about how great the machine is + + align:start position:0% +is either about how great the machine is + + + align:start position:0% +is either about how great the machine is +or how happy or unhappy the worker is. + + align:start position:0% +or how happy or unhappy the worker is. + + + align:start position:0% +or how happy or unhappy the worker is. +They rarely tell you how the m what's + + align:start position:0% +They rarely tell you how the m what's + + + align:start position:0% +They rarely tell you how the m what's +really going on because that's not what + + align:start position:0% +really going on because that's not what + + + align:start position:0% +really going on because that's not what +industrial photography has been about + + align:start position:0% +industrial photography has been about + + + align:start position:0% +industrial photography has been about +for the most part. Uh, I have nothing + + align:start position:0% +for the most part. Uh, I have nothing + + + align:start position:0% +for the most part. Uh, I have nothing +against how great the machine is or how + + align:start position:0% +against how great the machine is or how + + + align:start position:0% +against how great the machine is or how +unhappy or happy the worker is, but I + + align:start position:0% +unhappy or happy the worker is, but I + + + align:start position:0% +unhappy or happy the worker is, but I +was I have a different interest. All + + align:start position:0% +was I have a different interest. All + + + align:start position:0% +was I have a different interest. All +right. The other person is Charles + + align:start position:0% +right. The other person is Charles + + + align:start position:0% +right. The other person is Charles +Marval, who I mentioned + + align:start position:0% +Marval, who I mentioned + + + align:start position:0% +Marval, who I mentioned +before. Uh, I think this is what I want. + + align:start position:0% +before. Uh, I think this is what I want. + + + align:start position:0% +before. Uh, I think this is what I want. +Yes. Uh, who was hired by um um Baron + + align:start position:0% +Yes. Uh, who was hired by um um Baron + + + align:start position:0% +Yes. Uh, who was hired by um um Baron +Houseman to photograph Paris before and + + align:start position:0% +Houseman to photograph Paris before and + + + align:start position:0% +Houseman to photograph Paris before and +after it was eviscerated. + + align:start position:0% + + + + align:start position:0% + +and and he so he literally + + align:start position:0% +and and he so he literally + + + align:start position:0% +and and he so he literally +systematically photographed the Paris + + align:start position:0% +systematically photographed the Paris + + + align:start position:0% +systematically photographed the Paris +before and you can buy books with a + + align:start position:0% +before and you can buy books with a + + + align:start position:0% +before and you can buy books with a +thousand illustrations thousand of his + + align:start position:0% +thousand illustrations thousand of his + + + align:start position:0% +thousand illustrations thousand of his +images or 500 of his images and the best + + align:start position:0% +images or 500 of his images and the best + + + align:start position:0% +images or 500 of his images and the best +part the book I have is it shows you + + align:start position:0% +part the book I have is it shows you + + + align:start position:0% +part the book I have is it shows you +where he likely took the images + + align:start position:0% +where he likely took the images + + + align:start position:0% +where he likely took the images +from you know they figured out + + align:start position:0% +from you know they figured out + + + align:start position:0% +from you know they figured out +perspective which and the third person + + align:start position:0% +perspective which and the third person + + + align:start position:0% +perspective which and the third person +uh who sort of gives me courage is um + + align:start position:0% +uh who sort of gives me courage is um + + + align:start position:0% +uh who sort of gives me courage is um +nope Not that I'm + + align:start position:0% +nope Not that I'm + + + align:start position:0% +nope Not that I'm +sorry. Oops. Excuse + + align:start position:0% + + + + align:start position:0% + +me. Is uh Eugene Aette who you probably + + align:start position:0% +me. Is uh Eugene Aette who you probably + + + align:start position:0% +me. Is uh Eugene Aette who you probably +heard about who um John Sharowski u sort + + align:start position:0% +heard about who um John Sharowski u sort + + + align:start position:0% +heard about who um John Sharowski u sort +of idealized the Museum of Modern Art. + + align:start position:0% +of idealized the Museum of Modern Art. + + + align:start position:0% +of idealized the Museum of Modern Art. +And this is one of his photographs of a + + align:start position:0% +And this is one of his photographs of a + + + align:start position:0% +And this is one of his photographs of a +uh I don't think I can make it bigger. + + align:start position:0% +uh I don't think I can make it bigger. + + + align:start position:0% +uh I don't think I can make it bigger. +I'll try, but I don't think Can I? No, + + align:start position:0% +I'll try, but I don't think Can I? No, + + + align:start position:0% +I'll try, but I don't think Can I? No, +it won't matter. All right. Uh this is + + align:start position:0% +it won't matter. All right. Uh this is + + + align:start position:0% +it won't matter. All right. Uh this is +of a of a store + + align:start position:0% +of a of a store + + + align:start position:0% +of a of a store +window in + + align:start position:0% +window in + + + align:start position:0% +window in +Paris and he he does he has seven or + + align:start position:0% +Paris and he he does he has seven or + + + align:start position:0% +Paris and he he does he has seven or +eight different topics from store + + align:start position:0% +eight different topics from store + + + align:start position:0% +eight different topics from store +windows to parks to interiors and so + + align:start position:0% +windows to parks to interiors and so + + + align:start position:0% +windows to parks to interiors and so +forth and he makes these images for + + align:start position:0% +forth and he makes these images for + + + align:start position:0% +forth and he makes these images for +artists to use. Right? He said I'm not + + align:start position:0% +artists to use. Right? He said I'm not + + + align:start position:0% +artists to use. Right? He said I'm not +I'm not a photo an artist. I'm just I + + align:start position:0% +I'm not a photo an artist. I'm just I + + + align:start position:0% +I'm not a photo an artist. I'm just I +just make uh + + align:start position:0% +just make uh + + + align:start position:0% +just make uh +documents. So even though azis really is + + align:start position:0% +documents. So even though azis really is + + + align:start position:0% +documents. So even though azis really is +a great artist I'm delighted to have + + align:start position:0% +a great artist I'm delighted to have + + + align:start position:0% +a great artist I'm delighted to have +someone who said that. + + align:start position:0% +someone who said that. + + + align:start position:0% +someone who said that. +Uh the last reason why I can do this + + align:start position:0% +Uh the last reason why I can do this + + + align:start position:0% +Uh the last reason why I can do this +work is because it's fundable. I've been + + align:start position:0% +work is because it's fundable. I've been + + + align:start position:0% +work is because it's fundable. I've been +able to get some grants to do + + align:start position:0% +able to get some grants to do + + + align:start position:0% +able to get some grants to do +it. Uh that's very important. Not for + + align:start position:0% +it. Uh that's very important. Not for + + + align:start position:0% +it. Uh that's very important. Not for +two reasons. One, because it's a good + + align:start position:0% +two reasons. One, because it's a good + + + align:start position:0% +two reasons. One, because it's a good +way of scaring off the people who tell + + align:start position:0% +way of scaring off the people who tell + + + align:start position:0% +way of scaring off the people who tell +you you shouldn't do it. In a + + align:start position:0% +you you shouldn't do it. In a + + + align:start position:0% +you you shouldn't do it. In a +university, if you can get a grant from + + align:start position:0% +university, if you can get a grant from + + + align:start position:0% +university, if you can get a grant from +a respectable people to let you do + + align:start position:0% +a respectable people to let you do + + + align:start position:0% +a respectable people to let you do +something, they pay attention. + + align:start position:0% +something, they pay attention. + + + align:start position:0% +something, they pay attention. +I mean, you know that it's it's the + + align:start position:0% +I mean, you know that it's it's the + + + align:start position:0% +I mean, you know that it's it's the +it's maybe you don't know it, but if you + + align:start position:0% +it's maybe you don't know it, but if you + + + align:start position:0% +it's maybe you don't know it, but if you +don't, you should. And the other thing + + align:start position:0% +don't, you should. And the other thing + + + align:start position:0% +don't, you should. And the other thing +is that it buys off time that you need. + + align:start position:0% +is that it buys off time that you need. + + + align:start position:0% +is that it buys off time that you need. +You know, if you start going out three + + align:start position:0% +You know, if you start going out three + + + align:start position:0% +You know, if you start going out three +or four days a week to photograph every + + align:start position:0% +or four days a week to photograph every + + + align:start position:0% +or four days a week to photograph every +morning, and remember, every hour you + + align:start position:0% +morning, and remember, every hour you + + + align:start position:0% +morning, and remember, every hour you +spend photographing usually involves two + + align:start position:0% +spend photographing usually involves two + + + align:start position:0% +spend photographing usually involves two +hours of cataloging time in the end. + + align:start position:0% +hours of cataloging time in the end. + + + align:start position:0% +hours of cataloging time in the end. +Remember, I have I've not mentioned + + align:start position:0% +Remember, I have I've not mentioned + + + align:start position:0% +Remember, I have I've not mentioned +this, but I should finally I'll be + + align:start position:0% +this, but I should finally I'll be + + + align:start position:0% +this, but I should finally I'll be +through in two minutes. is I have uh um + + align:start position:0% +through in two minutes. is I have uh um + + + align:start position:0% +through in two minutes. is I have uh um +Excel um spreadsheets listing all my + + align:start position:0% +Excel um spreadsheets listing all my + + + align:start position:0% +Excel um spreadsheets listing all my +images by their + + align:start position:0% +images by their + + + align:start position:0% +images by their +topics. Every factory, every church, + + align:start position:0% +topics. Every factory, every church, + + + align:start position:0% +topics. Every factory, every church, +every + + align:start position:0% + + + + align:start position:0% + +street. I have maps of + + align:start position:0% +street. I have maps of + + + align:start position:0% +street. I have maps of +them. So there's an enormous amount of + + align:start position:0% +them. So there's an enormous amount of + + + align:start position:0% +them. So there's an enormous amount of +work and to do that so they're + + align:start position:0% +work and to do that so they're + + + align:start position:0% +work and to do that so they're +reasonably accurate. I'm not talking + + align:start position:0% +reasonably accurate. I'm not talking + + + align:start position:0% +reasonably accurate. I'm not talking +about perfect, but reasonably accurate + + align:start position:0% +about perfect, but reasonably accurate + + + align:start position:0% +about perfect, but reasonably accurate +turns out to be a lot of work, + + align:start position:0% +turns out to be a lot of work, + + + align:start position:0% +turns out to be a lot of work, +especially if you're not as perfect as I + + align:start position:0% +especially if you're not as perfect as I + + + align:start position:0% +especially if you're not as perfect as I +am. No, you're as imperfect as I am. You + + align:start position:0% +am. No, you're as imperfect as I am. You + + + align:start position:0% +am. No, you're as imperfect as I am. You +know, you just have to go back and keep + + align:start position:0% +know, you just have to go back and keep + + + align:start position:0% +know, you just have to go back and keep +doing it. Uh, and sometimes you can't + + align:start position:0% +doing it. Uh, and sometimes you can't + + + align:start position:0% +doing it. Uh, and sometimes you can't +remember where you took the photographs. + + align:start position:0% +remember where you took the photographs. + + + align:start position:0% +remember where you took the photographs. +You pay for every sin, by the way. Every + + align:start position:0% +You pay for every sin, by the way. Every + + + align:start position:0% +You pay for every sin, by the way. Every +time you don't take good notes, you pay + + align:start position:0% +time you don't take good notes, you pay + + + align:start position:0% +time you don't take good notes, you pay +for + + align:start position:0% +for + + + align:start position:0% +for +it. All right, let me close. I think + + align:start position:0% +it. All right, let me close. I think + + + align:start position:0% +it. All right, let me close. I think +that the notion of inquiry and sensing + + align:start position:0% +that the notion of inquiry and sensing + + + align:start position:0% +that the notion of inquiry and sensing +place, as you call this thing, is superb + + align:start position:0% +place, as you call this thing, is superb + + + align:start position:0% +place, as you call this thing, is superb +description of what I'm up to. + + align:start position:0% +description of what I'm up to. + + + align:start position:0% +description of what I'm up to. +Um, what I've done is there's an outline + + align:start position:0% +Um, what I've done is there's an outline + + + align:start position:0% +Um, what I've done is there's an outline +over there that a handout for those of + + align:start position:0% +over there that a handout for those of + + + align:start position:0% +over there that a handout for those of +you who want it, which is an outline of + + align:start position:0% +you who want it, which is an outline of + + + align:start position:0% +you who want it, which is an outline of +my talk, but also includes a two-page + + align:start position:0% +my talk, but also includes a two-page + + + align:start position:0% +my talk, but also includes a two-page +essay which I call systematic reflective + + align:start position:0% +essay which I call systematic reflective + + + align:start position:0% +essay which I call systematic reflective +fieldwork because I've been challenged + + align:start position:0% +fieldwork because I've been challenged + + + align:start position:0% +fieldwork because I've been challenged +by people who say, "Well, how can I rely + + align:start position:0% +by people who say, "Well, how can I rely + + + align:start position:0% +by people who say, "Well, how can I rely +on your data and so forth?" I've had to + + align:start position:0% +on your data and so forth?" I've had to + + + align:start position:0% +on your data and so forth?" I've had to +think a lot about how do you justify + + align:start position:0% +think a lot about how do you justify + + + align:start position:0% +think a lot about how do you justify +doing this kind of work to your uh + + align:start position:0% +doing this kind of work to your uh + + + align:start position:0% +doing this kind of work to your uh +skeptical colleagues? And I'm not + + align:start position:0% +skeptical colleagues? And I'm not + + + align:start position:0% +skeptical colleagues? And I'm not +talking about people who just want to + + align:start position:0% +talking about people who just want to + + + align:start position:0% +talking about people who just want to +give you trouble. I'm talking about + + align:start position:0% +give you trouble. I'm talking about + + + align:start position:0% +give you trouble. I'm talking about +people who are honestly + + align:start position:0% +people who are honestly + + + align:start position:0% +people who are honestly +skeptical, you know, who who who uh + + align:start position:0% +skeptical, you know, who who who uh + + + align:start position:0% +skeptical, you know, who who who uh +think it's better to do a statistical + + align:start position:0% +think it's better to do a statistical + + + align:start position:0% +think it's better to do a statistical +analysis or who somehow say, well, what + + align:start position:0% +analysis or who somehow say, well, what + + + align:start position:0% +analysis or who somehow say, well, what +about what you're leaving out? And my + + align:start position:0% +about what you're leaving out? And my + + + align:start position:0% +about what you're leaving out? And my +job in doing this project was to figure + + align:start position:0% +job in doing this project was to figure + + + align:start position:0% +job in doing this project was to figure +out how to justify it. And uh about a + + align:start position:0% +out how to justify it. And uh about a + + + align:start position:0% +out how to justify it. And uh about a +week ago, maybe two weeks ago, I said, + + align:start position:0% +week ago, maybe two weeks ago, I said, + + + align:start position:0% +week ago, maybe two weeks ago, I said, +well, I started looking through my notes + + align:start position:0% +well, I started looking through my notes + + + align:start position:0% +well, I started looking through my notes +and I I I figured out a story I could + + align:start position:0% +and I I I figured out a story I could + + + align:start position:0% +and I I I figured out a story I could +tell, which is what I call the + + align:start position:0% +tell, which is what I call the + + + align:start position:0% +tell, which is what I call the +systematic reflective fieldwork. The + + align:start position:0% +systematic reflective fieldwork. The + + + align:start position:0% +systematic reflective fieldwork. The +systematic as you can get from what I'm + + align:start position:0% +systematic as you can get from what I'm + + + align:start position:0% +systematic as you can get from what I'm +doing is you keep doing lots of it in an + + align:start position:0% +doing is you keep doing lots of it in an + + + align:start position:0% +doing is you keep doing lots of it in an +organized way. Reflective, you try to + + align:start position:0% +organized way. Reflective, you try to + + + align:start position:0% +organized way. Reflective, you try to +understand what you're doing and you do + + align:start position:0% +understand what you're doing and you do + + + align:start position:0% +understand what you're doing and you do +lots of + + align:start position:0% + + + + align:start position:0% + +fieldwork. Uh is that enough? That's a + + align:start position:0% +fieldwork. Uh is that enough? That's a + + + align:start position:0% +fieldwork. Uh is that enough? That's a +good question. But that's what, you + + align:start position:0% +good question. But that's what, you + + + align:start position:0% +good question. But that's what, you +know, what justifies what I do. Um, I + + align:start position:0% +know, what justifies what I do. Um, I + + + align:start position:0% +know, what justifies what I do. Um, I +have a terrific time doing this. I'm + + align:start position:0% +have a terrific time doing this. I'm + + + align:start position:0% +have a terrific time doing this. I'm +getting away with murder. But, uh, but I + + align:start position:0% +getting away with murder. But, uh, but I + + + align:start position:0% +getting away with murder. But, uh, but I +think it's really valuable. What happens + + align:start position:0% +think it's really valuable. What happens + + + align:start position:0% +think it's really valuable. What happens +with all this work is ends up an archive + + align:start position:0% +with all this work is ends up an archive + + + align:start position:0% +with all this work is ends up an archive +in the university. That's the most + + align:start position:0% +in the university. That's the most + + + align:start position:0% +in the university. That's the most +important thing. We put on shows and so + + align:start position:0% +important thing. We put on shows and so + + + align:start position:0% +important thing. We put on shows and so +forth, but I I'm not worried about + + align:start position:0% +forth, but I I'm not worried about + + + align:start position:0% +forth, but I I'm not worried about +making books of this or anything. That's + + align:start position:0% +making books of this or anything. That's + + + align:start position:0% +making books of this or anything. That's +not my purpose. My purpose is to have an + + align:start position:0% +not my purpose. My purpose is to have an + + + align:start position:0% +not my purpose. My purpose is to have an +archive that 60 to 100 years from now + + align:start position:0% +archive that 60 to 100 years from now + + + align:start position:0% +archive that 60 to 100 years from now +someone can use for work. + + align:start position:0% +someone can use for work. + + + align:start position:0% +someone can use for work. +That means if you want to do a good job + + align:start position:0% +That means if you want to do a good job + + + align:start position:0% +That means if you want to do a good job +on this, you got to give them the kinds + + align:start position:0% +on this, you got to give them the kinds + + + align:start position:0% +on this, you got to give them the kinds +of indexes and information so they don't + + align:start position:0% +of indexes and information so they don't + + + align:start position:0% +of indexes and information so they don't +have to go crazy trying to figure out + + align:start position:0% +have to go crazy trying to figure out + + + align:start position:0% +have to go crazy trying to figure out +what you + + align:start position:0% +what you + + + align:start position:0% +what you +did. Uh my as I said my next big project + + align:start position:0% +did. Uh my as I said my next big project + + + align:start position:0% +did. Uh my as I said my next big project +is going to be on or oral documentation + + align:start position:0% +is going to be on or oral documentation + + + align:start position:0% +is going to be on or oral documentation +and uh I've done a little but I don't + + align:start position:0% +and uh I've done a little but I don't + + + align:start position:0% +and uh I've done a little but I don't +trust my knowledge of that and we'll see + + align:start position:0% +trust my knowledge of that and we'll see + + + align:start position:0% +trust my knowledge of that and we'll see +what happens. Thank you. + + align:start position:0% +what happens. Thank you. + + + align:start position:0% +what happens. Thank you. +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +We've asked Mark Schuster to give brief + + align:start position:0% +We've asked Mark Schuster to give brief + + + align:start position:0% +We've asked Mark Schuster to give brief +comment. Oh, that's good. You do you + + align:start position:0% +comment. Oh, that's good. You do you + + + align:start position:0% +comment. Oh, that's good. You do you +need this? I guess I do. + + align:start position:0% + + + + align:start position:0% + +It's very good to have Marty back here + + align:start position:0% +It's very good to have Marty back here + + + align:start position:0% +It's very good to have Marty back here +in 10485 cuz as you can see, the level + + align:start position:0% +in 10485 cuz as you can see, the level + + + align:start position:0% +in 10485 cuz as you can see, the level +of energy goes up + + align:start position:0% +of energy goes up + + + align:start position:0% +of energy goes up +instantaneously. Uh, and I remember + + align:start position:0% +instantaneously. Uh, and I remember + + + align:start position:0% +instantaneously. Uh, and I remember +those days with great fondness. So, + + align:start position:0% +those days with great fondness. So, + + + align:start position:0% +those days with great fondness. So, +we're glad to have you back. Thank you. + + align:start position:0% +we're glad to have you back. Thank you. + + + align:start position:0% +we're glad to have you back. Thank you. +Um, so much to say uh that was that was + + align:start position:0% +Um, so much to say uh that was that was + + + align:start position:0% +Um, so much to say uh that was that was +raised uh in Marty's presentation and + + align:start position:0% +raised uh in Marty's presentation and + + + align:start position:0% +raised uh in Marty's presentation and +also by the the two-page essay here. Um, + + align:start position:0% +also by the the two-page essay here. Um, + + + align:start position:0% +also by the the two-page essay here. Um, +uh, but I want to start with something + + align:start position:0% +uh, but I want to start with something + + + align:start position:0% +uh, but I want to start with something +that's just been on my mind. The last + + align:start position:0% +that's just been on my mind. The last + + + align:start position:0% +that's just been on my mind. The last +two weeks, I've had guests from France + + align:start position:0% +two weeks, I've had guests from France + + + align:start position:0% +two weeks, I've had guests from France +uh, visiting with me and, uh, friends + + align:start position:0% +uh, visiting with me and, uh, friends + + + align:start position:0% +uh, visiting with me and, uh, friends +from many, many years ago. Uh, this was + + align:start position:0% +from many, many years ago. Uh, this was + + + align:start position:0% +from many, many years ago. Uh, this was +the first time in the United States for + + align:start position:0% +the first time in the United States for + + + align:start position:0% +the first time in the United States for +the husband. Um, the the wife had been + + align:start position:0% +the husband. Um, the the wife had been + + + align:start position:0% +the husband. Um, the the wife had been +here uh, as a youngster. her father + + align:start position:0% +here uh, as a youngster. her father + + + align:start position:0% +here uh, as a youngster. her father +worked in the embassy in in Washington + + align:start position:0% +worked in the embassy in in Washington + + + align:start position:0% +worked in the embassy in in Washington +and their 17-year-old son. And uh they + + align:start position:0% +and their 17-year-old son. And uh they + + + align:start position:0% +and their 17-year-old son. And uh they +did a lot of observing. He's an he's an + + align:start position:0% +did a lot of observing. He's an he's an + + + align:start position:0% +did a lot of observing. He's an he's an +artist, amateur artist. Uh but they did + + align:start position:0% +artist, amateur artist. Uh but they did + + + align:start position:0% +artist, amateur artist. Uh but they did +a lot of observing of the cities that + + align:start position:0% +a lot of observing of the cities that + + + align:start position:0% +a lot of observing of the cities that +they were in. Boston, New York, um + + align:start position:0% +they were in. Boston, New York, um + + + align:start position:0% +they were in. Boston, New York, um +Capean. Uh and I wonder if you might + + align:start position:0% +Capean. Uh and I wonder if you might + + + align:start position:0% +Capean. Uh and I wonder if you might +guess what the things they were most + + align:start position:0% +guess what the things they were most + + + align:start position:0% +guess what the things they were most +impressed + + align:start position:0% +impressed + + + align:start position:0% +impressed +with. Right? I asked them, you know, + + align:start position:0% +with. Right? I asked them, you know, + + + align:start position:0% +with. Right? I asked them, you know, +what did you find most interesting in + + align:start position:0% +what did you find most interesting in + + + align:start position:0% +what did you find most interesting in +walking around? + + align:start position:0% +walking around? + + + align:start position:0% +walking around? +What are you doing to me? The answer is + + align:start position:0% +What are you doing to me? The answer is + + + align:start position:0% +What are you doing to me? The answer is +not going to be on the screen. Um, + + align:start position:0% +not going to be on the screen. Um, + + + align:start position:0% +not going to be on the screen. Um, +uh, what were the most interesting + + align:start position:0% +uh, what were the most interesting + + + align:start position:0% +uh, what were the most interesting +things? And, uh, they said, first, + + align:start position:0% +things? And, uh, they said, first, + + + align:start position:0% +things? And, uh, they said, first, +everyone goes around carrying a beverage + + align:start position:0% +everyone goes around carrying a beverage + + + align:start position:0% +everyone goes around carrying a beverage +in their + + align:start position:0% +in their + + + align:start position:0% +in their +hand, right? Everyone goes around + + align:start position:0% +hand, right? Everyone goes around + + + align:start position:0% +hand, right? Everyone goes around +carrying a beverage in their hand. It's + + align:start position:0% +carrying a beverage in their hand. It's + + + align:start position:0% +carrying a beverage in their hand. It's +absolutely true and it's something that + + align:start position:0% +absolutely true and it's something that + + + align:start position:0% +absolutely true and it's something that +we don't notice. + + align:start position:0% +we don't notice. + + + align:start position:0% +we don't notice. +Um, second thing, in the United States, + + align:start position:0% +Um, second thing, in the United States, + + + align:start position:0% +Um, second thing, in the United States, +Q's + + align:start position:0% +Q's + + + align:start position:0% +Q's +work. And they were astonished. When we + + align:start position:0% +work. And they were astonished. When we + + + align:start position:0% +work. And they were astonished. When we +went into a restaurant, we put our name + + align:start position:0% +went into a restaurant, we put our name + + + align:start position:0% +went into a restaurant, we put our name +on a list. They said, "Come back in a + + align:start position:0% +on a list. They said, "Come back in a + + + align:start position:0% +on a list. They said, "Come back in a +half an hour." We walked around Newbury + + align:start position:0% +half an hour." We walked around Newbury + + + align:start position:0% +half an hour." We walked around Newbury +Port half an hour. We came back. They + + align:start position:0% +Port half an hour. We came back. They + + + align:start position:0% +Port half an hour. We came back. They +said, "Your table's ready." You know, + + align:start position:0% +said, "Your table's ready." You know, + + + align:start position:0% +said, "Your table's ready." You know, +and that everybody who was in front of + + align:start position:0% +and that everybody who was in front of + + + align:start position:0% +and that everybody who was in front of +us had been seated. And everybody who + + align:start position:0% +us had been seated. And everybody who + + + align:start position:0% +us had been seated. And everybody who +was behind us hadn't yet been seated. + + align:start position:0% +was behind us hadn't yet been seated. + + + align:start position:0% +was behind us hadn't yet been seated. +They couldn't believe it. Um, and the + + align:start position:0% +They couldn't believe it. Um, and the + + + align:start position:0% +They couldn't believe it. Um, and the +third one was uh was something that is a + + align:start position:0% +third one was uh was something that is a + + + align:start position:0% +third one was uh was something that is a +little harder to believe. They said, + + align:start position:0% +little harder to believe. They said, + + + align:start position:0% +little harder to believe. They said, +"It's so clean here." you know, when we + + align:start position:0% +"It's so clean here." you know, when we + + + align:start position:0% +"It's so clean here." you know, when we +go traveling other places and we say we + + align:start position:0% +go traveling other places and we say we + + + align:start position:0% +go traveling other places and we say we +go to Toronto and we say it's so clean + + align:start position:0% +go to Toronto and we say it's so clean + + + align:start position:0% +go to Toronto and we say it's so clean +or we go to Disneyland and say it's so + + align:start position:0% +or we go to Disneyland and say it's so + + + align:start position:0% +or we go to Disneyland and say it's so +clean. Uh well, here are French folks + + align:start position:0% +clean. Uh well, here are French folks + + + align:start position:0% +clean. Uh well, here are French folks +who came to Boston and + + align:start position:0% +who came to Boston and + + + align:start position:0% +who came to Boston and +um New York and said it's so clean. + + align:start position:0% +um New York and said it's so clean. + + + align:start position:0% +um New York and said it's so clean. +Now I was astonished at their power of + + align:start position:0% +Now I was astonished at their power of + + + align:start position:0% +Now I was astonished at their power of +observation and uh uh it's not a power + + align:start position:0% +observation and uh uh it's not a power + + + align:start position:0% +observation and uh uh it's not a power +of observation that I have and I think + + align:start position:0% +of observation that I have and I think + + + align:start position:0% +of observation that I have and I think +there's a clue in what uh Marty has said + + align:start position:0% +there's a clue in what uh Marty has said + + + align:start position:0% +there's a clue in what uh Marty has said +about this repetition to work at it and + + align:start position:0% +about this repetition to work at it and + + + align:start position:0% +about this repetition to work at it and +do it over and over again um that really + + align:start position:0% +do it over and over again um that really + + + align:start position:0% +do it over and over again um that really +um that really reminds us that it's hard + + align:start position:0% +um that really reminds us that it's hard + + + align:start position:0% +um that really reminds us that it's hard +work but it's work that's worth doing. + + align:start position:0% +work but it's work that's worth doing. + + + align:start position:0% +work but it's work that's worth doing. +Um Marty said toward the end, I don't + + align:start position:0% +Um Marty said toward the end, I don't + + + align:start position:0% +Um Marty said toward the end, I don't +have a methodology. I don't buy that for + + align:start position:0% +have a methodology. I don't buy that for + + + align:start position:0% +have a methodology. I don't buy that for +a second. You know, I think that he does + + align:start position:0% +a second. You know, I think that he does + + + align:start position:0% +a second. You know, I think that he does +have a methodology. It's an + + align:start position:0% +have a methodology. It's an + + + align:start position:0% +have a methodology. It's an +unconventional methodology perhaps. Um, + + align:start position:0% +unconventional methodology perhaps. Um, + + + align:start position:0% +unconventional methodology perhaps. Um, +but there are echoes of this methodology + + align:start position:0% +but there are echoes of this methodology + + + align:start position:0% +but there are echoes of this methodology +in things that many of us have read. Um, + + align:start position:0% +in things that many of us have read. Um, + + + align:start position:0% +in things that many of us have read. Um, +I I just grabbed a couple things off my + + align:start position:0% +I I just grabbed a couple things off my + + + align:start position:0% +I I just grabbed a couple things off my +shelf. For example, + + align:start position:0% +shelf. For example, + + + align:start position:0% +shelf. For example, +um, I didn't bring the book down because + + align:start position:0% +um, I didn't bring the book down because + + + align:start position:0% +um, I didn't bring the book down because +it's too big, but uh, um, I remembered + + align:start position:0% +it's too big, but uh, um, I remembered + + + align:start position:0% +it's too big, but uh, um, I remembered +when Larry Vale and I taught + + align:start position:0% +when Larry Vale and I taught + + + align:start position:0% +when Larry Vale and I taught +quantitative qualit excuse me, + + align:start position:0% +quantitative qualit excuse me, + + + align:start position:0% +quantitative qualit excuse me, +qualitative methods. Uh, and I want to + + align:start position:0% +qualitative methods. Uh, and I want to + + + align:start position:0% +qualitative methods. Uh, and I want to +disagree about that in a second. Uh we + + align:start position:0% +disagree about that in a second. Uh we + + + align:start position:0% +disagree about that in a second. Uh we +used an essay that Kevin Lynch wrote + + align:start position:0% +used an essay that Kevin Lynch wrote + + + align:start position:0% +used an essay that Kevin Lynch wrote +which was called A Walk Around the Block + + align:start position:0% +which was called A Walk Around the Block + + + align:start position:0% +which was called A Walk Around the Block +published in 1959. Uh it's reproduced in + + align:start position:0% +published in 1959. Uh it's reproduced in + + + align:start position:0% +published in 1959. Uh it's reproduced in +Michael Southworth's collection of the + + align:start position:0% +Michael Southworth's collection of the + + + align:start position:0% +Michael Southworth's collection of the +published articles of Kevin Lynch. Um + + align:start position:0% +published articles of Kevin Lynch. Um + + + align:start position:0% +published articles of Kevin Lynch. Um +and uh it uses a methodology that's a + + align:start position:0% +and uh it uses a methodology that's a + + + align:start position:0% +and uh it uses a methodology that's a +first cousin to what Marty was talking + + align:start position:0% +first cousin to what Marty was talking + + + align:start position:0% +first cousin to what Marty was talking +about. Um he would take people downtown + + align:start position:0% +about. Um he would take people downtown + + + align:start position:0% +about. Um he would take people downtown +and they would walk Newbury Street, + + align:start position:0% +and they would walk Newbury Street, + + + align:start position:0% +and they would walk Newbury Street, +Arlington Street, the alley between + + align:start position:0% +Arlington Street, the alley between + + + align:start position:0% +Arlington Street, the alley between +Newbury Street and uh and and uh Boilson + + align:start position:0% +Newbury Street and uh and and uh Boilson + + + align:start position:0% +Newbury Street and uh and and uh Boilson +Street, Berkeley Street, and he would + + align:start position:0% +Street, Berkeley Street, and he would + + + align:start position:0% +Street, Berkeley Street, and he would +ask people, you know, we are about to + + align:start position:0% +ask people, you know, we are about to + + + align:start position:0% +ask people, you know, we are about to +take a short walk. Don't look for + + align:start position:0% +take a short walk. Don't look for + + + align:start position:0% +take a short walk. Don't look for +anything in particular, but tell me + + align:start position:0% +anything in particular, but tell me + + + align:start position:0% +anything in particular, but tell me +about the things you see, hear or smell, + + align:start position:0% +about the things you see, hear or smell, + + + align:start position:0% +about the things you see, hear or smell, +everything and anything you notice. Um + + align:start position:0% +everything and anything you notice. Um + + + align:start position:0% +everything and anything you notice. Um +and he tries to capture um in an essay + + align:start position:0% +and he tries to capture um in an essay + + + align:start position:0% +and he tries to capture um in an essay +then what people have told him about + + align:start position:0% +then what people have told him about + + + align:start position:0% +then what people have told him about +this little voyage around one small + + align:start position:0% +this little voyage around one small + + + align:start position:0% +this little voyage around one small +simple ordinary block uh in Boston. It + + align:start position:0% +simple ordinary block uh in Boston. It + + + align:start position:0% +simple ordinary block uh in Boston. It +was probably more ordinary then than it + + align:start position:0% +was probably more ordinary then than it + + + align:start position:0% +was probably more ordinary then than it +is today. Um or uh 1980 Grady Clay + + align:start position:0% +is today. Um or uh 1980 Grady Clay + + + align:start position:0% +is today. Um or uh 1980 Grady Clay +closeup how to read the American city. + + align:start position:0% +closeup how to read the American city. + + + align:start position:0% +closeup how to read the American city. +Uh 1985 Alan Jacobs looking at cities. U + + align:start position:0% +Uh 1985 Alan Jacobs looking at cities. U + + + align:start position:0% +Uh 1985 Alan Jacobs looking at cities. U +John Stillgo 1998 outside lies magic. um + + align:start position:0% +John Stillgo 1998 outside lies magic. um + + + align:start position:0% +John Stillgo 1998 outside lies magic. um +or Grady Clay again in 1998. Uh Real + + align:start position:0% +or Grady Clay again in 1998. Uh Real + + + align:start position:0% +or Grady Clay again in 1998. Uh Real +Places um an unconventional guide to the + + align:start position:0% +Places um an unconventional guide to the + + + align:start position:0% +Places um an unconventional guide to the +American landscape. Um all of these you + + align:start position:0% +American landscape. Um all of these you + + + align:start position:0% +American landscape. Um all of these you +are using similar methodologies to what + + align:start position:0% +are using similar methodologies to what + + + align:start position:0% +are using similar methodologies to what +Marty is up to. Um but uh and all of + + align:start position:0% +Marty is up to. Um but uh and all of + + + align:start position:0% +Marty is up to. Um but uh and all of +them are dealing with the same + + align:start position:0% +them are dealing with the same + + + align:start position:0% +them are dealing with the same +fundamental problem which I think is is + + align:start position:0% +fundamental problem which I think is is + + + align:start position:0% +fundamental problem which I think is is +Marty's problem although he hasn't quite + + align:start position:0% +Marty's problem although he hasn't quite + + + align:start position:0% +Marty's problem although he hasn't quite +named it and that is how do I take it + + align:start position:0% +named it and that is how do I take it + + + align:start position:0% +named it and that is how do I take it +home with + + align:start position:0% +home with + + + align:start position:0% +home with +me? Right? Because there's two things + + align:start position:0% +me? Right? Because there's two things + + + align:start position:0% +me? Right? Because there's two things +going on here. One thing is his + + align:start position:0% +going on here. One thing is his + + + align:start position:0% +going on here. One thing is his +experience of being out in the field + + align:start position:0% +experience of being out in the field + + + align:start position:0% +experience of being out in the field +looking at these things and and + + align:start position:0% +looking at these things and and + + + align:start position:0% +looking at these things and and +reflecting upon them and the other is + + align:start position:0% +reflecting upon them and the other is + + + align:start position:0% +reflecting upon them and the other is +how do I capture that and take it home + + align:start position:0% +how do I capture that and take it home + + + align:start position:0% +how do I capture that and take it home +and save it so that someone else can + + align:start position:0% +and save it so that someone else can + + + align:start position:0% +and save it so that someone else can +have something of the same experience. + + align:start position:0% +have something of the same experience. + + + align:start position:0% +have something of the same experience. +Okay? And and I think Marty would be the + + align:start position:0% +Okay? And and I think Marty would be the + + + align:start position:0% +Okay? And and I think Marty would be the +first to admit that that person 50 or 60 + + align:start position:0% +first to admit that that person 50 or 60 + + + align:start position:0% +first to admit that that person 50 or 60 +years from now will not have the same + + align:start position:0% +years from now will not have the same + + + align:start position:0% +years from now will not have the same +experience. Right? It'll be a different + + align:start position:0% +experience. Right? It'll be a different + + + align:start position:0% +experience. Right? It'll be a different +experience. Um although you can u you + + align:start position:0% +experience. Um although you can u you + + + align:start position:0% +experience. Um although you can u you +can work as hard as you possibly can to + + align:start position:0% +can work as hard as you possibly can to + + + align:start position:0% +can work as hard as you possibly can to +make it an uh as equivalent experience + + align:start position:0% +make it an uh as equivalent experience + + + align:start position:0% +make it an uh as equivalent experience +as you possibly uh can. Now um you you + + align:start position:0% +as you possibly uh can. Now um you you + + + align:start position:0% +as you possibly uh can. Now um you you +you spoke about qualitative methods and + + align:start position:0% +you spoke about qualitative methods and + + + align:start position:0% +you spoke about qualitative methods and +I just uh up until that moment in your + + align:start position:0% +I just uh up until that moment in your + + + align:start position:0% +I just uh up until that moment in your +talk um I was having very fond memories + + align:start position:0% +talk um I was having very fond memories + + + align:start position:0% +talk um I was having very fond memories +of this course that we used to offer in + + align:start position:0% +of this course that we used to offer in + + + align:start position:0% +of this course that we used to offer in +the group called qualitative methods. + + align:start position:0% +the group called qualitative methods. + + + align:start position:0% +the group called qualitative methods. +Larry and I taught it once or twice. Uh + + align:start position:0% +Larry and I taught it once or twice. Uh + + + align:start position:0% +Larry and I taught it once or twice. Uh +Larry taught it with Sam another time or + + align:start position:0% +Larry taught it with Sam another time or + + + align:start position:0% +Larry taught it with Sam another time or +two. Um, and it's been a long while + + align:start position:0% +two. Um, and it's been a long while + + + align:start position:0% +two. Um, and it's been a long while +since we've actually uh actually taught + + align:start position:0% +since we've actually uh actually taught + + + align:start position:0% +since we've actually uh actually taught +it. Um, and perhaps the way in which we + + align:start position:0% +it. Um, and perhaps the way in which we + + + align:start position:0% +it. Um, and perhaps the way in which we +went about that is not a way that you + + align:start position:0% +went about that is not a way that you + + + align:start position:0% +went about that is not a way that you +would today accept after your + + align:start position:0% +would today accept after your + + + align:start position:0% +would today accept after your +experiences in the field. Um, um, but I + + align:start position:0% +experiences in the field. Um, um, but I + + + align:start position:0% +experiences in the field. Um, um, but I +think it's a mistake. Um, and I think + + align:start position:0% +think it's a mistake. Um, and I think + + + align:start position:0% +think it's a mistake. Um, and I think +many of the students think it's a + + align:start position:0% +many of the students think it's a + + + align:start position:0% +many of the students think it's a +mistake that we don't offer such a + + align:start position:0% +mistake that we don't offer such a + + + align:start position:0% +mistake that we don't offer such a +course. Uh, and that we really ought to + + align:start position:0% +course. Uh, and that we really ought to + + + align:start position:0% +course. Uh, and that we really ought to +um, and maybe um, you suggest, uh, to + + align:start position:0% +um, and maybe um, you suggest, uh, to + + + align:start position:0% +um, and maybe um, you suggest, uh, to +us, uh, Marty a way to do that. Stillgo + + align:start position:0% +us, uh, Marty a way to do that. Stillgo + + + align:start position:0% +us, uh, Marty a way to do that. Stillgo +in the in the beginning of Stillgo's + + align:start position:0% +in the in the beginning of Stillgo's + + + align:start position:0% +in the in the beginning of Stillgo's +book he talks in the very first few + + align:start position:0% +book he talks in the very first few + + + align:start position:0% +book he talks in the very first few +pages about how he started + + align:start position:0% +pages about how he started + + + align:start position:0% +pages about how he started +conventionally for for many years with a + + align:start position:0% +conventionally for for many years with a + + + align:start position:0% +conventionally for for many years with a +syllabus and eventually he sort of threw + + align:start position:0% +syllabus and eventually he sort of threw + + + align:start position:0% +syllabus and eventually he sort of threw +the syllabus away and he said what my + + align:start position:0% +the syllabus away and he said what my + + + align:start position:0% +the syllabus away and he said what my +course is about is about exploring and + + align:start position:0% +course is about is about exploring and + + + align:start position:0% +course is about is about exploring and +so as we explore what we're going to + + align:start position:0% +so as we explore what we're going to + + + align:start position:0% +so as we explore what we're going to +explore is going to change from year to + + align:start position:0% +explore is going to change from year to + + + align:start position:0% +explore is going to change from year to +year as uh I get reactions from students + + align:start position:0% +year as uh I get reactions from students + + + align:start position:0% +year as uh I get reactions from students +as they come back from their experiences + + align:start position:0% +as they come back from their experiences + + + align:start position:0% +as they come back from their experiences +in in the field. Um now I want to say + + align:start position:0% +in in the field. Um now I want to say + + + align:start position:0% +in in the field. Um now I want to say +something about photography I suppose uh + + align:start position:0% +something about photography I suppose uh + + + align:start position:0% +something about photography I suppose uh +because that's what this is about. Um + + align:start position:0% +because that's what this is about. Um + + + align:start position:0% +because that's what this is about. Um +and and maybe uh speak about it a little + + align:start position:0% +and and maybe uh speak about it a little + + + align:start position:0% +and and maybe uh speak about it a little +bit more personally. I have found as I + + align:start position:0% +bit more personally. I have found as I + + + align:start position:0% +bit more personally. I have found as I +have traveled of late I have often left + + align:start position:0% +have traveled of late I have often left + + + align:start position:0% +have traveled of late I have often left +my camera at home. Uh and the reason is + + align:start position:0% +my camera at home. Uh and the reason is + + + align:start position:0% +my camera at home. Uh and the reason is +because I got really tired of looking uh + + align:start position:0% +because I got really tired of looking uh + + + align:start position:0% +because I got really tired of looking uh +at the world through a rectangular uh + + align:start position:0% +at the world through a rectangular uh + + + align:start position:0% +at the world through a rectangular uh +frame um and spending all my time + + align:start position:0% +frame um and spending all my time + + + align:start position:0% +frame um and spending all my time +viewing it this way rather than viewing + + align:start position:0% +viewing it this way rather than viewing + + + align:start position:0% +viewing it this way rather than viewing +it this way. Maybe the key is the wide + + align:start position:0% +it this way. Maybe the key is the wide + + + align:start position:0% +it this way. Maybe the key is the wide +angle lens. Um uh and maybe that's what + + align:start position:0% +angle lens. Um uh and maybe that's what + + + align:start position:0% +angle lens. Um uh and maybe that's what +would make a difference. I do take the + + align:start position:0% +would make a difference. I do take the + + + align:start position:0% +would make a difference. I do take the +camera along when when um uh uh I'm I'm + + align:start position:0% +camera along when when um uh uh I'm I'm + + + align:start position:0% +camera along when when um uh uh I'm I'm +on a project and need uh you know visual + + align:start position:0% +on a project and need uh you know visual + + + align:start position:0% +on a project and need uh you know visual +evidence of one sort or another to + + align:start position:0% +evidence of one sort or another to + + + align:start position:0% +evidence of one sort or another to +illustrate the project. But I have found + + align:start position:0% +illustrate the project. But I have found + + + align:start position:0% +illustrate the project. But I have found +personally that it has been more + + align:start position:0% +personally that it has been more + + + align:start position:0% +personally that it has been more +restrictive for me. That makes the trick + + align:start position:0% +restrictive for me. That makes the trick + + + align:start position:0% +restrictive for me. That makes the trick +of bringing it home much more difficult. + + align:start position:0% +of bringing it home much more difficult. + + + align:start position:0% +of bringing it home much more difficult. +Right? Is it a journal? Is it just your + + align:start position:0% +Right? Is it a journal? Is it just your + + + align:start position:0% +Right? Is it a journal? Is it just your +memory? Is it is it some other form of + + align:start position:0% +memory? Is it is it some other form of + + + align:start position:0% +memory? Is it is it some other form of +recording? um that uh allows you to + + align:start position:0% +recording? um that uh allows you to + + + align:start position:0% +recording? um that uh allows you to +bring some of this home to catalog it to + + align:start position:0% +bring some of this home to catalog it to + + + align:start position:0% +bring some of this home to catalog it to +categorize it to uh you know you're + + align:start position:0% +categorize it to uh you know you're + + + align:start position:0% +categorize it to uh you know you're +doing a lot of very traditional social + + align:start position:0% +doing a lot of very traditional social + + + align:start position:0% +doing a lot of very traditional social +science things. You're categorizing and + + align:start position:0% +science things. You're categorizing and + + + align:start position:0% +science things. You're categorizing and +you're sorting and you're organizing and + + align:start position:0% +you're sorting and you're organizing and + + + align:start position:0% +you're sorting and you're organizing and +I I bet that Excel spreadsheet is + + align:start position:0% +I I bet that Excel spreadsheet is + + + align:start position:0% +I I bet that Excel spreadsheet is +organized by uh you could sort it by uh + + align:start position:0% +organized by uh you could sort it by uh + + + align:start position:0% +organized by uh you could sort it by uh +the various columns which helps you sort + + align:start position:0% +the various columns which helps you sort + + + align:start position:0% +the various columns which helps you sort +it into different categories. That's not + + align:start position:0% +it into different categories. That's not + + + align:start position:0% +it into different categories. That's not +very far away from uh the traditional + + align:start position:0% +very far away from uh the traditional + + + align:start position:0% +very far away from uh the traditional +social social science methodology. Um uh + + align:start position:0% +social social science methodology. Um uh + + + align:start position:0% +social social science methodology. Um uh +and and and finally I end with a with a + + align:start position:0% +and and and finally I end with a with a + + + align:start position:0% +and and and finally I end with a with a +with a question. I mentioned the name + + align:start position:0% +with a question. I mentioned the name + + + align:start position:0% +with a question. I mentioned the name +Tim Samuelson to you once before and I + + align:start position:0% +Tim Samuelson to you once before and I + + + align:start position:0% +Tim Samuelson to you once before and I +you haven't you haven't contacted Tim. + + align:start position:0% +you haven't you haven't contacted Tim. + + + align:start position:0% +you haven't you haven't contacted Tim. +Tim is uh Tim has worked with um uh one + + align:start position:0% +Tim is uh Tim has worked with um uh one + + + align:start position:0% +Tim is uh Tim has worked with um uh one +of the photographers who came early and + + align:start position:0% +of the photographers who came early and + + + align:start position:0% +of the photographers who came early and +help me remember did did a book called + + align:start position:0% +help me remember did did a book called + + + align:start position:0% +help me remember did did a book called +Unexpected Chicago + + align:start position:0% +Unexpected Chicago + + + align:start position:0% +Unexpected Chicago +with Camille right um and they're + + align:start position:0% +with Camille right um and they're + + + align:start position:0% +with Camille right um and they're +they're they've been working on + + align:start position:0% +they're they've been working on + + + align:start position:0% +they're they've been working on +storefront churches in Chicago. Yes. Um, + + align:start position:0% +storefront churches in Chicago. Yes. Um, + + + align:start position:0% +storefront churches in Chicago. Yes. Um, +and Tim is the cultural historian for + + align:start position:0% +and Tim is the cultural historian for + + + align:start position:0% +and Tim is the cultural historian for +the city of Chicago and would be an + + align:start position:0% +the city of Chicago and would be an + + + align:start position:0% +the city of Chicago and would be an +interesting person to to to talk to + + align:start position:0% +interesting person to to to talk to + + + align:start position:0% +interesting person to to to talk to +about their experiences going out and + + align:start position:0% +about their experiences going out and + + + align:start position:0% +about their experiences going out and +photographing uh and documenting the + + align:start position:0% +photographing uh and documenting the + + + align:start position:0% +photographing uh and documenting the +storefront um churches. So, there are + + align:start position:0% +storefront um churches. So, there are + + + align:start position:0% +storefront um churches. So, there are +some thoughts that I'd like to put on + + align:start position:0% +some thoughts that I'd like to put on + + + align:start position:0% +some thoughts that I'd like to put on +the table. Uh, we need to give you a + + align:start position:0% +the table. Uh, we need to give you a + + + align:start position:0% +the table. Uh, we need to give you a +chance to to ask questions. So, let's uh + + align:start position:0% +chance to to ask questions. So, let's uh + + + align:start position:0% +chance to to ask questions. So, let's uh +let's turn to that and maybe I'll give + + align:start position:0% +let's turn to that and maybe I'll give + + + align:start position:0% +let's turn to that and maybe I'll give +this back to you, Marty, and you can + + align:start position:0% +this back to you, Marty, and you can + + + align:start position:0% +this back to you, Marty, and you can +Well, I think it's better to let Oh, let + + align:start position:0% +Well, I think it's better to let Oh, let + + + align:start position:0% +Well, I think it's better to let Oh, let +them ask us questions, but they're going + + align:start position:0% +them ask us questions, but they're going + + + align:start position:0% +them ask us questions, but they're going +to be of you. So, Right. Yeah. + + align:start position:0% +to be of you. So, Right. Yeah. + + + align:start position:0% +to be of you. So, Right. Yeah. +questions. + + align:start position:0% +questions. + + + align:start position:0% +questions. +Well, I just have to add one question in + + align:start position:0% +Well, I just have to add one question in + + + align:start position:0% +Well, I just have to add one question in +relationship to Mark's comment about + + align:start position:0% +relationship to Mark's comment about + + + align:start position:0% +relationship to Mark's comment about +about the work. Is it categorized? In + + align:start position:0% +about the work. Is it categorized? In + + + align:start position:0% +about the work. Is it categorized? In +other words, if I look at the 800 + + align:start position:0% +other words, if I look at the 800 + + + align:start position:0% +other words, if I look at the 800 +uh pictures of Pentecostal + + align:start position:0% +uh pictures of Pentecostal + + + align:start position:0% +uh pictures of Pentecostal +churches, are they categorized or are + + align:start position:0% +churches, are they categorized or are + + + align:start position:0% +churches, are they categorized or are +they just categorized by dress and so + + align:start position:0% +they just categorized by dress and so + + + align:start position:0% +they just categorized by dress and so +forth? + + align:start position:0% +forth? + + + align:start position:0% +forth? +There's information, for example, about + + align:start position:0% +There's information, for example, about + + + align:start position:0% +There's information, for example, about +what their uh what their uh biblical + + align:start position:0% +what their uh what their uh biblical + + + align:start position:0% +what their uh what their uh biblical +pass passages are. That's one thing. It + + align:start position:0% +pass passages are. That's one thing. It + + + align:start position:0% +pass passages are. That's one thing. It +lists the biblical passages in each and + + align:start position:0% +lists the biblical passages in each and + + + align:start position:0% +lists the biblical passages in each and +another column lists the the symbols + + align:start position:0% +another column lists the the symbols + + + align:start position:0% +another column lists the the symbols +that are on the church. Another column + + align:start position:0% +that are on the church. Another column + + + align:start position:0% +that are on the church. Another column +uh what else is there? Those are the two + + align:start position:0% +uh what else is there? Those are the two + + + align:start position:0% +uh what else is there? Those are the two +things I can think of immediately. If I + + align:start position:0% +things I can think of immediately. If I + + + align:start position:0% +things I can think of immediately. If I +were an architect, by the way, and the + + align:start position:0% +were an architect, by the way, and the + + + align:start position:0% +were an architect, by the way, and the +architects think differently, they would + + align:start position:0% +architects think differently, they would + + + align:start position:0% +architects think differently, they would +start saying how has the building been + + align:start position:0% +start saying how has the building been + + + align:start position:0% +start saying how has the building been +modified or color or color. Yeah. Well, + + align:start position:0% +modified or color or color. Yeah. Well, + + + align:start position:0% +modified or color or color. Yeah. Well, +no, I didn't do that. Um and obviously + + align:start position:0% +no, I didn't do that. Um and obviously + + + align:start position:0% +no, I didn't do that. Um and obviously +one could do much more of that work. But + + align:start position:0% +one could do much more of that work. But + + + align:start position:0% +one could do much more of that work. But +the architects for example uh there was + + align:start position:0% +the architects for example uh there was + + + align:start position:0% +the architects for example uh there was +a woman in Houston who was concerned + + align:start position:0% +a woman in Houston who was concerned + + + align:start position:0% +a woman in Houston who was concerned +about the modifications of the buildings + + align:start position:0% +about the modifications of the buildings + + + align:start position:0% +about the modifications of the buildings +which was interesting but nothing I + + align:start position:0% +which was interesting but nothing I + + + align:start position:0% +which was interesting but nothing I +spent much time on frankly. So but the + + align:start position:0% +spent much time on frankly. So but the + + + align:start position:0% +spent much time on frankly. So but the +categorizations are not very deep I must + + align:start position:0% +categorizations are not very deep I must + + + align:start position:0% +categorizations are not very deep I must +admit. Um someone else would have to go + + align:start position:0% +admit. Um someone else would have to go + + + align:start position:0% +admit. Um someone else would have to go +through it all and start thinking much + + align:start position:0% +through it all and start thinking much + + + align:start position:0% +through it all and start thinking much +more deeply about what they were looking + + align:start position:0% +more deeply about what they were looking + + + align:start position:0% +more deeply about what they were looking +for. For example, what are your + + align:start position:0% +for. For example, what are your + + + align:start position:0% +for. For example, what are your +neighbors? My favorite one was next to a + + align:start position:0% +neighbors? My favorite one was next to a + + + align:start position:0% +neighbors? My favorite one was next to a +to a uh you know a hot bed + + align:start position:0% +to a uh you know a hot bed + + + align:start position:0% +to a uh you know a hot bed +motel you know for prostitutes + + align:start position:0% + + + + align:start position:0% + +on Western Avenue. I had just a couple + + align:start position:0% +on Western Avenue. I had just a couple + + + align:start position:0% +on Western Avenue. I had just a couple +of other uh comments about this. For one + + align:start position:0% +of other uh comments about this. For one + + + align:start position:0% +of other uh comments about this. For one +one thing, I'm sitting here with + + align:start position:0% +one thing, I'm sitting here with + + + align:start position:0% +one thing, I'm sitting here with +tremendous regret because uh at one + + align:start position:0% +tremendous regret because uh at one + + + align:start position:0% +tremendous regret because uh at one +point in my career, I was documenting + + align:start position:0% +point in my career, I was documenting + + + align:start position:0% +point in my career, I was documenting +bridges in Boston and came across an + + align:start position:0% +bridges in Boston and came across an + + + align:start position:0% +bridges in Boston and came across an +archive + + align:start position:0% +archive + + + align:start position:0% +archive +uh in a bridge house in South Boston, + + align:start position:0% +uh in a bridge house in South Boston, + + + align:start position:0% +uh in a bridge house in South Boston, +which were the engineering records, + + align:start position:0% +which were the engineering records, + + + align:start position:0% +which were the engineering records, +photographs of every bridge in Boston, + + align:start position:0% +photographs of every bridge in Boston, + + + align:start position:0% +photographs of every bridge in Boston, +taken every year for about 50 years. Oh + + align:start position:0% +taken every year for about 50 years. Oh + + + align:start position:0% +taken every year for about 50 years. Oh +my god. And somebody had rescued them. + + align:start position:0% +my god. And somebody had rescued them. + + + align:start position:0% +my god. And somebody had rescued them. +And I took a bunch of photos for what I + + align:start position:0% +And I took a bunch of photos for what I + + + align:start position:0% +And I took a bunch of photos for what I +was working on at the time. I probably + + align:start position:0% +was working on at the time. I probably + + + align:start position:0% +was working on at the time. I probably +still have those photographs, but I'm + + align:start position:0% +still have those photographs, but I'm + + + align:start position:0% +still have those photographs, but I'm +sure the rest of it along with the + + align:start position:0% +sure the rest of it along with the + + + align:start position:0% +sure the rest of it along with the +bridge house and one of the last + + align:start position:0% +bridge house and one of the last + + + align:start position:0% +bridge house and one of the last +remaining bridges of this type were + + align:start position:0% +remaining bridges of this type were + + + align:start position:0% +remaining bridges of this type were +swept away. And when you were showing + + align:start position:0% +swept away. And when you were showing + + + align:start position:0% +swept away. And when you were showing +this, I said to myself, goodness, there + + align:start position:0% +this, I said to myself, goodness, there + + + align:start position:0% +this, I said to myself, goodness, there +are lots of archives actually like this + + align:start position:0% +are lots of archives actually like this + + + align:start position:0% +are lots of archives actually like this +out there that people have done based + + align:start position:0% +out there that people have done based + + + align:start position:0% +out there that people have done based +upon their particular cut at the world. + + align:start position:0% +upon their particular cut at the world. + + + align:start position:0% +upon their particular cut at the world. +Uh engineering for example, all these + + align:start position:0% +Uh engineering for example, all these + + + align:start position:0% +Uh engineering for example, all these +bridges are documented for other + + align:start position:0% +bridges are documented for other + + + align:start position:0% +bridges are documented for other +reasons. uh and it might be quite + + align:start position:0% +reasons. uh and it might be quite + + + align:start position:0% +reasons. uh and it might be quite +extraordinary to begin to collect those + + align:start position:0% +extraordinary to begin to collect those + + + align:start position:0% +extraordinary to begin to collect those +archives into a meta. No, that's exactly + + align:start position:0% +archives into a meta. No, that's exactly + + + align:start position:0% +archives into a meta. No, that's exactly +what's valuable about a university. The + + align:start position:0% +what's valuable about a university. The + + + align:start position:0% +what's valuable about a university. The +thing about universities is they don't + + align:start position:0% +thing about universities is they don't + + + align:start position:0% +thing about universities is they don't +disappear too soon, too rapidly and they + + align:start position:0% +disappear too soon, too rapidly and they + + + align:start position:0% +disappear too soon, too rapidly and they +don't throw out archives too often and + + align:start position:0% +don't throw out archives too often and + + + align:start position:0% +don't throw out archives too often and +that's what their big advantage is. You + + align:start position:0% +that's what their big advantage is. You + + + align:start position:0% +that's what their big advantage is. You +know, they're long-standing + + align:start position:0% +know, they're long-standing + + + align:start position:0% +know, they're long-standing +institutions and uh you know, libraries + + align:start position:0% +institutions and uh you know, libraries + + + align:start position:0% +institutions and uh you know, libraries +are like that too, but there are very + + align:start position:0% +are like that too, but there are very + + + align:start position:0% +are like that too, but there are very +few places that would do that. You know, + + align:start position:0% +few places that would do that. You know, + + + align:start position:0% +few places that would do that. You know, +most corporations eventually with their + + align:start position:0% +most corporations eventually with their + + + align:start position:0% +most corporations eventually with their +corporate uh what's + + align:start position:0% +corporate uh what's + + + align:start position:0% +corporate uh what's +um the Huntington Library just got the + + align:start position:0% +um the Huntington Library just got the + + + align:start position:0% +um the Huntington Library just got the +corporate archives of got something of + + align:start position:0% +corporate archives of got something of + + + align:start position:0% +corporate archives of got something of +the Southern California + + align:start position:0% +the Southern California + + + align:start position:0% +the Southern California +Edison with photographs just infinite + + align:start position:0% +Edison with photographs just infinite + + + align:start position:0% +Edison with photographs just infinite +amounts of photographs that were taken + + align:start position:0% +amounts of photographs that were taken + + + align:start position:0% +amounts of photographs that were taken +for technical reasons typicized way what + + align:start position:0% +for technical reasons typicized way what + + + align:start position:0% +for technical reasons typicized way what +a lot of them were done in a very + + align:start position:0% +a lot of them were done in a very + + + align:start position:0% +a lot of them were done in a very +regularized way. Yes. first grade + + align:start position:0% +regularized way. Yes. first grade + + + align:start position:0% +regularized way. Yes. first grade +quality. And the major problem is at + + align:start position:0% +quality. And the major problem is at + + + align:start position:0% +quality. And the major problem is at +some point it's too expensive to keep + + align:start position:0% +some point it's too expensive to keep + + + align:start position:0% +some point it's too expensive to keep +them. So they shred them or you know and + + align:start position:0% +them. So they shred them or you know and + + + align:start position:0% +them. So they shred them or you know and +so you know anybody here who's historian + + align:start position:0% +so you know anybody here who's historian + + + align:start position:0% +so you know anybody here who's historian +has worked in archives knows that the + + align:start position:0% +has worked in archives knows that the + + + align:start position:0% +has worked in archives knows that the +miracle is if you could only get them to + + align:start position:0% +miracle is if you could only get them to + + + align:start position:0% +miracle is if you could only get them to +forget about their what they own for 100 + + align:start position:0% +forget about their what they own for 100 + + + align:start position:0% +forget about their what they own for 100 +years. I just had two other sorry random + + align:start position:0% +years. I just had two other sorry random + + + align:start position:0% +years. I just had two other sorry random +comments. The other comment I had was + + align:start position:0% +comments. The other comment I had was + + + align:start position:0% +comments. The other comment I had was +that if you didn't do Pentecostal + + align:start position:0% +that if you didn't do Pentecostal + + + align:start position:0% +that if you didn't do Pentecostal +churches, + + align:start position:0% +churches, + + + align:start position:0% +churches, +just pick anything, move to the building + + align:start position:0% +just pick anything, move to the building + + + align:start position:0% +just pick anything, move to the building +next door. Yeah. And then go out and + + align:start position:0% +next door. Yeah. And then go out and + + + align:start position:0% +next door. Yeah. And then go out and +record all buildings like that building. + + align:start position:0% +record all buildings like that building. + + + align:start position:0% +record all buildings like that building. +You would come up with a similar and + + align:start position:0% +You would come up with a similar and + + + align:start position:0% +You would come up with a similar and +equally provocative. No, I think not. I + + align:start position:0% +equally provocative. No, I think not. I + + + align:start position:0% +equally provocative. No, I think not. I +think actually taste matters. I think + + align:start position:0% +think actually taste matters. I think + + + align:start position:0% +think actually taste matters. I think +that I have pretty good taste. Uh maybe + + align:start position:0% +that I have pretty good taste. Uh maybe + + + align:start position:0% +that I have pretty good taste. Uh maybe +not superb, but not bad. I mean my trick + + align:start position:0% +not superb, but not bad. I mean my trick + + + align:start position:0% +not superb, but not bad. I mean my trick +was most people who I mean including + + align:start position:0% +was most people who I mean including + + + align:start position:0% +was most people who I mean including +Vgara do not worry about Pentecostal + + align:start position:0% +Vgara do not worry about Pentecostal + + + align:start position:0% +Vgara do not worry about Pentecostal +theology. They just like the pictures. + + align:start position:0% +theology. They just like the pictures. + + + align:start position:0% +theology. They just like the pictures. +They just think it's they get off on the + + align:start position:0% +They just think it's they get off on the + + + align:start position:0% +They just think it's they get off on the +religiosity. But do they know anything + + align:start position:0% +religiosity. But do they know anything + + + align:start position:0% +religiosity. But do they know anything +about the history of Pentecostalism? + + align:start position:0% +about the history of Pentecostalism? + + + align:start position:0% +about the history of Pentecostalism? +Very little. Do they care about the + + align:start position:0% +Very little. Do they care about the + + + align:start position:0% +Very little. Do they care about the +theology? Very + + align:start position:0% +theology? Very + + + align:start position:0% +theology? Very +little. I think I mean that's why I find + + align:start position:0% +little. I think I mean that's why I find + + + align:start position:0% +little. I think I mean that's why I find +Tom Roman's pictures a little bit too + + align:start position:0% +Tom Roman's pictures a little bit too + + + align:start position:0% +Tom Roman's pictures a little bit too +much. you know, yes, it's nice that + + align:start position:0% +much. you know, yes, it's nice that + + + align:start position:0% +much. you know, yes, it's nice that +they're rolling their eyes back and + + align:start position:0% +they're rolling their eyes back and + + + align:start position:0% +they're rolling their eyes back and +they're getting the feeling the spirit, + + align:start position:0% +they're getting the feeling the spirit, + + + align:start position:0% +they're getting the feeling the spirit, +but I think it that we owe those people + + align:start position:0% +but I think it that we owe those people + + + align:start position:0% +but I think it that we owe those people +more than that. Um, and it may turn out + + align:start position:0% +more than that. Um, and it may turn out + + + align:start position:0% +more than that. Um, and it may turn out +that the stores next to the buildings + + align:start position:0% +that the stores next to the buildings + + + align:start position:0% +that the stores next to the buildings +next to the churches have an interesting + + align:start position:0% +next to the churches have an interesting + + + align:start position:0% +next to the churches have an interesting +story and maybe it's better, but my + + align:start position:0% +story and maybe it's better, but my + + + align:start position:0% +story and maybe it's better, but my +intuitions are no, but you might be + + align:start position:0% +intuitions are no, but you might be + + + align:start position:0% +intuitions are no, but you might be +right. Well, I think my thought was + + align:start position:0% +right. Well, I think my thought was + + + align:start position:0% +right. Well, I think my thought was +slightly just slightly different and I + + align:start position:0% +slightly just slightly different and I + + + align:start position:0% +slightly just slightly different and I +not meaning this to be skeptical any + + align:start position:0% +not meaning this to be skeptical any + + + align:start position:0% +not meaning this to be skeptical any +way. I'm just saying that one of the + + align:start position:0% +way. I'm just saying that one of the + + + align:start position:0% +way. I'm just saying that one of the +beauties of this is I could go to Greek + + align:start position:0% +beauties of this is I could go to Greek + + + align:start position:0% +beauties of this is I could go to Greek +revival homes and all the Greek revival + + align:start position:0% +revival homes and all the Greek revival + + + align:start position:0% +revival homes and all the Greek revival +homes. I could go to homes made with a + + align:start position:0% +homes. I could go to homes made with a + + + align:start position:0% +homes. I could go to homes made with a +certain kind of pattern of brick or made + + align:start position:0% +certain kind of pattern of brick or made + + + align:start position:0% +certain kind of pattern of brick or made +by and the environment is filled with an + + align:start position:0% +by and the environment is filled with an + + + align:start position:0% +by and the environment is filled with an +infinite number of these patterns and + + align:start position:0% +infinite number of these patterns and + + + align:start position:0% +infinite number of these patterns and +the problem is to choose examples that + + align:start position:0% +the problem is to choose examples that + + + align:start position:0% +the problem is to choose examples that +allow for rich + + align:start position:0% +allow for rich + + + align:start position:0% +allow for rich +elaboration and it depends on your own + + align:start position:0% +elaboration and it depends on your own + + + align:start position:0% +elaboration and it depends on your own +skills. You mean I cannot do what an + + align:start position:0% +skills. You mean I cannot do what an + + + align:start position:0% +skills. You mean I cannot do what an +architect will do you know who sees the + + align:start position:0% +architect will do you know who sees the + + + align:start position:0% +architect will do you know who sees the +world entirely + + align:start position:0% +world entirely + + + align:start position:0% +world entirely +differently you know I mean acutely + + align:start position:0% +differently you know I mean acutely + + + align:start position:0% +differently you know I mean acutely +aware of when they have foam columns + + align:start position:0% +aware of when they have foam columns + + + align:start position:0% +aware of when they have foam columns +rather than you know real columns all + + align:start position:0% +rather than you know real columns all + + + align:start position:0% +rather than you know real columns all +right and all that stuff but so but I + + align:start position:0% +right and all that stuff but so but I + + + align:start position:0% +right and all that stuff but so but I +think that so it's a question and why in + + align:start position:0% +think that so it's a question and why in + + + align:start position:0% +think that so it's a question and why in +the world was I interested in that + + align:start position:0% +the world was I interested in that + + + align:start position:0% +the world was I interested in that +religious stuff I've written a book on + + align:start position:0% +religious stuff I've written a book on + + + align:start position:0% +religious stuff I've written a book on +um religious figures as model + + align:start position:0% +um religious figures as model + + + align:start position:0% +um religious figures as model +entrepreneurs the first chapter was on + + align:start position:0% +entrepreneurs the first chapter was on + + + align:start position:0% +entrepreneurs the first chapter was on +Augustine the second chapter was on + + align:start position:0% +Augustine the second chapter was on + + + align:start position:0% +Augustine the second chapter was on +Moses all right I got a And for that + + align:start position:0% +Moses all right I got a And for that + + + align:start position:0% +Moses all right I got a And for that +too, which is why I + + align:start position:0% +too, which is why I + + + align:start position:0% +too, which is why I +mean the point is that I was acutely + + align:start position:0% +mean the point is that I was acutely + + + align:start position:0% +mean the point is that I was acutely +aware there that if you take the + + align:start position:0% +aware there that if you take the + + + align:start position:0% +aware there that if you take the +theology seriously as such, you learn a + + align:start position:0% +theology seriously as such, you learn a + + + align:start position:0% +theology seriously as such, you learn a +lot. Not that you have to believe + + align:start position:0% + + + + align:start position:0% + +anything. But if you take it seriously, + + align:start position:0% +anything. But if you take it seriously, + + + align:start position:0% +anything. But if you take it seriously, +you go very far. And that was my that + + align:start position:0% +you go very far. And that was my that + + + align:start position:0% +you go very far. And that was my that +was my discovery. In other words, if I + + align:start position:0% +was my discovery. In other words, if I + + + align:start position:0% +was my discovery. In other words, if I +understood why Augustine did what he + + align:start position:0% +understood why Augustine did what he + + + align:start position:0% +understood why Augustine did what he +did, I could understand things about + + align:start position:0% +did, I could understand things about + + + align:start position:0% +did, I could understand things about +decision-m that were + + align:start position:0% +decision-m that were + + + align:start position:0% +decision-m that were +illuminating. Now, do I do I think he + + align:start position:0% +illuminating. Now, do I do I think he + + + align:start position:0% +illuminating. Now, do I do I think he +really had heard some tree talking to + + align:start position:0% +really had heard some tree talking to + + + align:start position:0% +really had heard some tree talking to +him, you know, in the backyard when he + + align:start position:0% +him, you know, in the backyard when he + + + align:start position:0% +him, you know, in the backyard when he +said, you know, tree said, "Take it and + + align:start position:0% +said, you know, tree said, "Take it and + + + align:start position:0% +said, you know, tree said, "Take it and +read." And opened up the book and + + align:start position:0% +read." And opened up the book and + + + align:start position:0% +read." And opened up the book and +pointed or that that what's his name? U + + align:start position:0% +pointed or that that what's his name? U + + + align:start position:0% +pointed or that that what's his name? U +had a flash of life and fell off the + + align:start position:0% +had a flash of life and fell off the + + + align:start position:0% +had a flash of life and fell off the +donkey. + + align:start position:0% +donkey. + + + align:start position:0% +donkey. +Paul, who cares? + + align:start position:0% +Paul, who cares? + + + align:start position:0% +Paul, who cares? +But you know I'm a Jew from + + align:start position:0% +But you know I'm a Jew from + + + align:start position:0% +But you know I'm a Jew from +Brooklyn so it doesn't matter to me. But + + align:start position:0% +Brooklyn so it doesn't matter to me. But + + + align:start position:0% +Brooklyn so it doesn't matter to me. But +I mean you know for Christians it's + + align:start position:0% +I mean you know for Christians it's + + + align:start position:0% +I mean you know for Christians it's +obvious for certain kinds of Christians + + align:start position:0% +obvious for certain kinds of Christians + + + align:start position:0% +obvious for certain kinds of Christians +it's very important issue but as a + + align:start position:0% +it's very important issue but as a + + + align:start position:0% +it's very important issue but as a +scholar what matters is to take those + + align:start position:0% +scholar what matters is to take those + + + align:start position:0% +scholar what matters is to take those +events as serious accounts which then + + align:start position:0% +events as serious accounts which then + + + align:start position:0% +events as serious accounts which then +are + + align:start position:0% +are + + + align:start position:0% +are +illuminating and that's what really is + + align:start position:0% +illuminating and that's what really is + + + align:start position:0% +illuminating and that's what really is +wonderful. Um but I think your point is + + align:start position:0% +wonderful. Um but I think your point is + + + align:start position:0% +wonderful. Um but I think your point is +very well taken. I mean I don't think + + align:start position:0% +very well taken. I mean I don't think + + + align:start position:0% +very well taken. I mean I don't think +that I know what's interesting. I don't + + align:start position:0% +that I know what's interesting. I don't + + + align:start position:0% +that I know what's interesting. I don't +know, you know, I mean, you know, a good + + align:start position:0% +know, you know, I mean, you know, a good + + + align:start position:0% +know, you know, I mean, you know, a good +Marxist probably could take the uh, you + + align:start position:0% +Marxist probably could take the uh, you + + + align:start position:0% +Marxist probably could take the uh, you +know, the garbage on the street and + + align:start position:0% +know, the garbage on the street and + + + align:start position:0% +know, the garbage on the street and +convert it to a good + + align:start position:0% +convert it to a good + + + align:start position:0% +convert it to a good +story, but probably the good Marxist is + + align:start position:0% +story, but probably the good Marxist is + + + align:start position:0% +story, but probably the good Marxist is +Carl and you know, the rest don't do as + + align:start position:0% +Carl and you know, the rest don't do as + + + align:start position:0% +Carl and you know, the rest don't do as +well. + + align:start position:0% + + + + align:start position:0% + +Yes, sir. Uh well first of all thank you + + align:start position:0% +Yes, sir. Uh well first of all thank you + + + align:start position:0% +Yes, sir. Uh well first of all thank you +for your for your presentation which was + + align:start position:0% +for your for your presentation which was + + + align:start position:0% +for your for your presentation which was +very impressive especially as as a + + align:start position:0% +very impressive especially as as a + + + align:start position:0% +very impressive especially as as a +various recordings and uh pictures also + + align:start position:0% +various recordings and uh pictures also + + + align:start position:0% +various recordings and uh pictures also +offer a window on the on the + + align:start position:0% +offer a window on the on the + + + align:start position:0% +offer a window on the on the +organizations of the space that you're + + align:start position:0% +organizations of the space that you're + + + align:start position:0% +organizations of the space that you're +looking into like you know the + + align:start position:0% +looking into like you know the + + + align:start position:0% +looking into like you know the +organization of the of + + align:start position:0% +organization of the of + + + align:start position:0% +organization of the of +the of the Pentecostalist meeting. Yeah. + + align:start position:0% +the of the Pentecostalist meeting. Yeah. + + + align:start position:0% +the of the Pentecostalist meeting. Yeah. +Uh but my question is + + align:start position:0% +Uh but my question is + + + align:start position:0% +Uh but my question is +uh the great 19th century surveys of + + align:start position:0% +uh the great 19th century surveys of + + + align:start position:0% +uh the great 19th century surveys of +cities which this makes me in a way + + align:start position:0% +cities which this makes me in a way + + + align:start position:0% +cities which this makes me in a way +think of also uh had a very particular + + align:start position:0% +think of also uh had a very particular + + + align:start position:0% +think of also uh had a very particular +motivation very particular purpose which + + align:start position:0% +motivation very particular purpose which + + + align:start position:0% +motivation very particular purpose which +is to map you know the proletarian and + + align:start position:0% +is to map you know the proletarian and + + + align:start position:0% +is to map you know the proletarian and +understand how how it could be how to + + align:start position:0% +understand how how it could be how to + + + align:start position:0% +understand how how it could be how to +control the disease the source of + + align:start position:0% +control the disease the source of + + + align:start position:0% +control the disease the source of +disease exactly how would be normalized + + align:start position:0% +disease exactly how would be normalized + + + align:start position:0% +disease exactly how would be normalized +afterwards etc. So I was wondering if + + align:start position:0% +afterwards etc. So I was wondering if + + + align:start position:0% +afterwards etc. So I was wondering if +what your particular motivations from + + align:start position:0% +what your particular motivations from + + + align:start position:0% +what your particular motivations from +from an outsider perspective. It seems + + align:start position:0% +from an outsider perspective. It seems + + + align:start position:0% +from an outsider perspective. It seems +that it's it is motivated by the the + + align:start position:0% +that it's it is motivated by the the + + + align:start position:0% +that it's it is motivated by the the +freakiness of of Los Angeles is sort of + + align:start position:0% +freakiness of of Los Angeles is sort of + + + align:start position:0% +freakiness of of Los Angeles is sort of +urban. Los Angeles is the least freaky + + align:start position:0% +urban. Los Angeles is the least freaky + + + align:start position:0% +urban. Los Angeles is the least freaky +places. It's very ordinary. I mean + + align:start position:0% +places. It's very ordinary. I mean + + + align:start position:0% +places. It's very ordinary. I mean +Boston seems weird to me. Uh but you + + align:start position:0% +Boston seems weird to me. Uh but you + + + align:start position:0% +Boston seems weird to me. Uh but you +know uh the whole thing of Los Angeles + + align:start position:0% +know uh the whole thing of Los Angeles + + + align:start position:0% +know uh the whole thing of Los Angeles +exceptionalism strikes me as unlikely to + + align:start position:0% +exceptionalism strikes me as unlikely to + + + align:start position:0% +exceptionalism strikes me as unlikely to +get you very far. But let me go back + + align:start position:0% +get you very far. But let me go back + + + align:start position:0% +get you very far. But let me go back +more seriously to your remark. Well the + + align:start position:0% +more seriously to your remark. Well the + + + align:start position:0% +more seriously to your remark. Well the +question is what what is what is driving + + align:start position:0% +question is what what is what is driving + + + align:start position:0% +question is what what is what is driving +you? was propelling you forward. What + + align:start position:0% +you? was propelling you forward. What + + + align:start position:0% +you? was propelling you forward. What +propels me forward? It's a good + + align:start position:0% +propels me forward? It's a good + + + align:start position:0% +propels me forward? It's a good +question. Why in the world will I get + + align:start position:0% +question. Why in the world will I get + + + align:start position:0% +question. Why in the world will I get +interested in such a thing? + + align:start position:0% +interested in such a thing? + + + align:start position:0% +interested in such a thing? +Um I one of the things is it was so + + align:start position:0% +Um I one of the things is it was so + + + align:start position:0% +Um I one of the things is it was so +interesting visually. Second of all, + + align:start position:0% +interesting visually. Second of all, + + + align:start position:0% +interesting visually. Second of all, +there were so many of them. And third, I + + align:start position:0% +there were so many of them. And third, I + + + align:start position:0% +there were so many of them. And third, I +had a feeling I knew I could do + + align:start position:0% +had a feeling I knew I could do + + + align:start position:0% +had a feeling I knew I could do +something with + + align:start position:0% +something with + + + align:start position:0% +something with +it. And those don't sound like like + + align:start position:0% +it. And those don't sound like like + + + align:start position:0% +it. And those don't sound like like +cleaning up the idiots in the world or, + + align:start position:0% +cleaning up the idiots in the world or, + + + align:start position:0% +cleaning up the idiots in the world or, +you know, solving problems. And maybe I + + align:start position:0% +you know, solving problems. And maybe I + + + align:start position:0% +you know, solving problems. And maybe I +do have some nefarious purposes, but I + + align:start position:0% +do have some nefarious purposes, but I + + + align:start position:0% +do have some nefarious purposes, but I +suspect a lot of it has to do with um + + align:start position:0% +suspect a lot of it has to do with um + + + align:start position:0% +suspect a lot of it has to do with um +and also it was distant from me. + + align:start position:0% +and also it was distant from me. + + + align:start position:0% +and also it was distant from me. +I mean I've gone for example where I + + align:start position:0% +I mean I've gone for example where I + + + align:start position:0% +I mean I've gone for example where I +live in Los Angeles there's lots of + + align:start position:0% +live in Los Angeles there's lots of + + + align:start position:0% +live in Los Angeles there's lots of +synagogues which are not storefront + + align:start position:0% +synagogues which are not storefront + + + align:start position:0% +synagogues which are not storefront +synagogues but there are you know and + + align:start position:0% +synagogues but there are you know and + + + align:start position:0% +synagogues but there are you know and +you know essentially four four Jews have + + align:start position:0% +you know essentially four four Jews have + + + align:start position:0% +you know essentially four four Jews have +five synagogues because you know they + + align:start position:0% +five synagogues because you know they + + + align:start position:0% +five synagogues because you know they +have one they wouldn't go to but the + + align:start position:0% +have one they wouldn't go to but the + + + align:start position:0% +have one they wouldn't go to but the +point is that uh the the the basic the + + align:start position:0% +point is that uh the the the basic the + + + align:start position:0% +point is that uh the the the basic the +point is that there is sectarianism + + align:start position:0% +point is that there is sectarianism + + + align:start position:0% +point is that there is sectarianism +there but they don't wear it in the same + + align:start position:0% +there but they don't wear it in the same + + + align:start position:0% +there but they don't wear it in the same +way. They don't it doesn't quite uh + + align:start position:0% +way. They don't it doesn't quite uh + + + align:start position:0% +way. They don't it doesn't quite uh +evidence it in the same way. All right. + + align:start position:0% +evidence it in the same way. All right. + + + align:start position:0% +evidence it in the same way. All right. +Uh but there is stuff like that. + + align:start position:0% + + + + align:start position:0% + +Uh and by the way, it wasn't only + + align:start position:0% +Uh and by the way, it wasn't only + + + align:start position:0% +Uh and by the way, it wasn't only +Pentecostal churches. Storefront + + align:start position:0% +Pentecostal churches. Storefront + + + align:start position:0% +Pentecostal churches. Storefront +churches include lots that are not + + align:start position:0% +churches include lots that are not + + + align:start position:0% +churches include lots that are not +Pentecostal. Uh and I I they're part of + + align:start position:0% +Pentecostal. Uh and I I they're part of + + + align:start position:0% +Pentecostal. Uh and I I they're part of +my large sample. Uh you know, but + + align:start position:0% +my large sample. Uh you know, but + + + align:start position:0% +my large sample. Uh you know, but +Pentecostalism is just very rich with + + align:start position:0% +Pentecostalism is just very rich with + + + align:start position:0% +Pentecostalism is just very rich with +sectarianism. That's what makes it so + + align:start position:0% +sectarianism. That's what makes it so + + + align:start position:0% +sectarianism. That's what makes it so +wonderful. Uh it starts out as one + + align:start position:0% +wonderful. Uh it starts out as one + + + align:start position:0% +wonderful. Uh it starts out as one +movement and then it gets racially sec + + align:start position:0% +movement and then it gets racially sec + + + align:start position:0% +movement and then it gets racially sec +and then it has arguments about whether + + align:start position:0% +and then it has arguments about whether + + + align:start position:0% +and then it has arguments about whether +it's the first or the the second or + + align:start position:0% +it's the first or the the second or + + + align:start position:0% +it's the first or the the second or +third um uh what is it you know um + + align:start position:0% +third um uh what is it you know um + + + align:start position:0% +third um uh what is it you know um +salvation I mean the whole bunch of + + align:start position:0% +salvation I mean the whole bunch of + + + align:start position:0% +salvation I mean the whole bunch of +interesting issues would split them + + align:start position:0% +interesting issues would split them + + + align:start position:0% +interesting issues would split them +up and uh and and therefore it says for + + align:start position:0% +up and uh and and therefore it says for + + + align:start position:0% +up and uh and and therefore it says for +example when it says read the Bible all + + align:start position:0% +example when it says read the Bible all + + + align:start position:0% +example when it says read the Bible all +right you know you'll see all that why + + align:start position:0% +right you know you'll see all that why + + + align:start position:0% +right you know you'll see all that why +do they say read the Bible because + + align:start position:0% +do they say read the Bible because + + + align:start position:0% +do they say read the Bible because +you're not supposed to listen to the + + align:start position:0% +you're not supposed to listen to the + + + align:start position:0% +you're not supposed to listen to the +church supposed to read the Bible. But + + align:start position:0% +church supposed to read the Bible. But + + + align:start position:0% +church supposed to read the Bible. But +it's more than that. If they have they + + align:start position:0% +it's more than that. If they have they + + + align:start position:0% +it's more than that. If they have they +say something in Spanish or English, + + align:start position:0% +say something in Spanish or English, + + + align:start position:0% +say something in Spanish or English, +there's always some argument that + + align:start position:0% +there's always some argument that + + + align:start position:0% +there's always some argument that +they're + + align:start position:0% + + + + align:start position:0% + +having. And I think I've always been + + align:start position:0% +having. And I think I've always been + + + align:start position:0% +having. And I think I've always been +fascinated by Protestant sectarianism. + + align:start position:0% +fascinated by Protestant sectarianism. + + + align:start position:0% +fascinated by Protestant sectarianism. +But why? Because I never understood it. + + align:start position:0% + + + + align:start position:0% + +Yes. + + align:start position:0% +Yes. + + + align:start position:0% +Yes. +Yes. + + align:start position:0% +Yes. + + + align:start position:0% +Yes. +you see can I make just a comment? Yes. + + align:start position:0% +you see can I make just a comment? Yes. + + + align:start position:0% +you see can I make just a comment? Yes. +On what you shared with us tonight which + + align:start position:0% +On what you shared with us tonight which + + + align:start position:0% +On what you shared with us tonight which +I enjoy very very much. + + align:start position:0% +I enjoy very very much. + + + align:start position:0% +I enjoy very very much. +When and I saw you + + align:start position:0% +When and I saw you + + + align:start position:0% +When and I saw you +here, you were concerned with + + align:start position:0% +here, you were concerned with + + + align:start position:0% +here, you were concerned with +possibility of falls + + align:start position:0% +possibility of falls + + + align:start position:0% +possibility of falls +where and the great + + align:start position:0% +where and the great + + + align:start position:0% +where and the great +difficulties operating those in any way + + align:start position:0% +difficulties operating those in any way + + + align:start position:0% +difficulties operating those in any way +that give you a predictive description + + align:start position:0% +that give you a predictive description + + + align:start position:0% +that give you a predictive description +the conditions that need to meet in + + align:start position:0% +the conditions that need to meet in + + + align:start position:0% +the conditions that need to meet in +order to perform + + align:start position:0% +order to perform + + + align:start position:0% +order to perform +well. And seems to be that you're + + align:start position:0% +well. And seems to be that you're + + + align:start position:0% +well. And seems to be that you're +exactly on that same track. wanted to + + align:start position:0% +exactly on that same track. wanted to + + + align:start position:0% +exactly on that same track. wanted to +move in the other direction. We said I + + align:start position:0% +move in the other direction. We said I + + + align:start position:0% +move in the other direction. We said I +want to enable those who would follow + + align:start position:0% +want to enable those who would follow + + + align:start position:0% +want to enable those who would follow +how the late 20th century city + + align:start position:0% +how the late 20th century city + + + align:start position:0% +how the late 20th century city +work to give causal accounts day by year + + align:start position:0% +work to give causal accounts day by year + + + align:start position:0% +work to give causal accounts day by year +of what the city was doing well but not + + align:start position:0% +of what the city was doing well but not + + + align:start position:0% +of what the city was doing well but not +let me see if I understand the change in + + align:start position:0% +let me see if I understand the change in + + + align:start position:0% +let me see if I understand the change in +my work is when I'm doing field work and + + align:start position:0% +my work is when I'm doing field work and + + + align:start position:0% +my work is when I'm doing field work and +remember I didn't always do field work + + align:start position:0% +remember I didn't always do field work + + + align:start position:0% +remember I didn't always do field work +most of my life all right most of my I + + align:start position:0% +most of my life all right most of my I + + + align:start position:0% +most of my life all right most of my I +sat in my office field work in the + + align:start position:0% +sat in my office field work in the + + + align:start position:0% +sat in my office field work in the +Yeah, at + + align:start position:0% +Yeah, at + + + align:start position:0% +Yeah, at +best mostly up here, but you know, and + + align:start position:0% +best mostly up here, but you know, and + + + align:start position:0% +best mostly up here, but you know, and +then I would go to the library to + + align:start position:0% +then I would go to the library to + + + align:start position:0% +then I would go to the library to +confirm it. But the point is this is a + + align:start position:0% +confirm it. But the point is this is a + + + align:start position:0% +confirm it. But the point is this is a +very different life I lead now. I mean, + + align:start position:0% +very different life I lead now. I mean, + + + align:start position:0% +very different life I lead now. I mean, +I don't feel like reading most of the + + align:start position:0% +I don't feel like reading most of the + + + align:start position:0% +I don't feel like reading most of the +time. What I want to do is go out and + + align:start position:0% +time. What I want to do is go out and + + + align:start position:0% +time. What I want to do is go out and +look. I go read because I want to + + align:start position:0% +look. I go read because I want to + + + align:start position:0% +look. I go read because I want to +understand + + align:start position:0% +understand + + + align:start position:0% +understand +something, you know, but it's a very + + align:start position:0% +something, you know, but it's a very + + + align:start position:0% +something, you know, but it's a very +you're right. It's it's it's a very big + + align:start position:0% +you're right. It's it's it's a very big + + + align:start position:0% +you're right. It's it's it's a very big +change. Uh it's not that my previous + + align:start position:0% +change. Uh it's not that my previous + + + align:start position:0% +change. Uh it's not that my previous +work wasn't empirical. It was very + + align:start position:0% +work wasn't empirical. It was very + + + align:start position:0% +work wasn't empirical. It was very +empirical to my mind. But this is driven + + align:start position:0% +empirical to my mind. But this is driven + + + align:start position:0% +empirical to my mind. But this is driven +by the + + align:start position:0% +by the + + + align:start position:0% +by the +world, you know. It's what the world + + align:start position:0% +world, you know. It's what the world + + + align:start position:0% +world, you know. It's what the world +takes hold of + + align:start position:0% +takes hold of + + + align:start position:0% +takes hold of +me. Does that say and it's very + + align:start position:0% +me. Does that say and it's very + + + align:start position:0% +me. Does that say and it's very +powerful. I mean, the example is my + + align:start position:0% +powerful. I mean, the example is my + + + align:start position:0% +powerful. I mean, the example is my +walking around Boston this morning since + + align:start position:0% +walking around Boston this morning since + + + align:start position:0% +walking around Boston this morning since +I got off the plane. Uh, and I used to + + align:start position:0% +I got off the plane. Uh, and I used to + + + align:start position:0% +I got off the plane. Uh, and I used to +live here, but I never walked around. I + + align:start position:0% +live here, but I never walked around. I + + + align:start position:0% +live here, but I never walked around. I +never saw + + align:start position:0% +never saw + + + align:start position:0% +never saw +anything. And no one else I did knew + + align:start position:0% +anything. And no one else I did knew + + + align:start position:0% +anything. And no one else I did knew +either did much of it as far as I know. + + align:start position:0% +either did much of it as far as I know. + + + align:start position:0% +either did much of it as far as I know. +They must have maybe they were closet uh + + align:start position:0% +They must have maybe they were closet uh + + + align:start position:0% +They must have maybe they were closet uh +viewers but they never mentioned it. But + + align:start position:0% +viewers but they never mentioned it. But + + + align:start position:0% +viewers but they never mentioned it. But +the point was that it was so interesting + + align:start position:0% +the point was that it was so interesting + + + align:start position:0% +the point was that it was so interesting +to look at. First of all I had new eyes + + align:start position:0% +to look at. First of all I had new eyes + + + align:start position:0% +to look at. First of all I had new eyes +right because you know I've seen other + + align:start position:0% +right because you know I've seen other + + + align:start position:0% +right because you know I've seen other +places and you + + align:start position:0% +places and you + + + align:start position:0% +places and you +know it was just it the world hit me and + + align:start position:0% +know it was just it the world hit me and + + + align:start position:0% +know it was just it the world hit me and +I I don't know what to do with it now. + + align:start position:0% +I I don't know what to do with it now. + + + align:start position:0% +I I don't know what to do with it now. +And you can say come on this is just + + align:start position:0% +And you can say come on this is just + + + align:start position:0% +And you can say come on this is just +Boston probably the most studied + + align:start position:0% +Boston probably the most studied + + + align:start position:0% +Boston probably the most studied +academically studied city in America. + + align:start position:0% +academically studied city in America. + + + align:start position:0% +academically studied city in America. +All + + align:start position:0% +All + + + align:start position:0% +All +right. But maybe other than Chicago and + + align:start position:0% +right. But maybe other than Chicago and + + + align:start position:0% +right. But maybe other than Chicago and +but it was remarkable what I saw and it + + align:start position:0% +but it was remarkable what I saw and it + + + align:start position:0% +but it was remarkable what I saw and it +will force me to think again and I + + align:start position:0% +will force me to think again and I + + + align:start position:0% +will force me to think again and I +probably will have to come back and do a + + align:start position:0% +probably will have to come back and do a + + + align:start position:0% +probably will have to come back and do a +whole bunch of photographing and + + align:start position:0% +whole bunch of photographing and + + + align:start position:0% +whole bunch of photographing and +thinking and probably write things on + + align:start position:0% +thinking and probably write things on + + + align:start position:0% +thinking and probably write things on +brick and some other things. And also + + align:start position:0% +brick and some other things. And also + + + align:start position:0% +brick and some other things. And also +the most interesting phenomena is the + + align:start position:0% +the most interesting phenomena is the + + + align:start position:0% +the most interesting phenomena is the +cheek by jouness of it. It's also in Los + + align:start position:0% +cheek by jouness of it. It's also in Los + + + align:start position:0% +cheek by jouness of it. It's also in Los +Angeles. The most interesting is how + + align:start position:0% +Angeles. The most interesting is how + + + align:start position:0% +Angeles. The most interesting is how +housing and industry are cheap by jou + + align:start position:0% +housing and industry are cheap by jou + + + align:start position:0% +housing and industry are cheap by jou +all over. + + align:start position:0% +all over. + + + align:start position:0% +all over. +If your big companies know, but if + + align:start position:0% +If your big companies know, but if + + + align:start position:0% +If your big companies know, but if +smaller factories and so forth, + + align:start position:0% +smaller factories and so forth, + + + align:start position:0% +smaller factories and so forth, +historically, you have an enormous + + align:start position:0% +historically, you have an enormous + + + align:start position:0% +historically, you have an enormous +amount of housing and factories across + + align:start position:0% +amount of housing and factories across + + + align:start position:0% +amount of housing and factories across +the street from each + + align:start position:0% +the street from each + + + align:start position:0% +the street from each +other and around each + + align:start position:0% +other and around each + + + align:start position:0% +other and around each +other. And I don't know if everybody + + align:start position:0% +other. And I don't know if everybody + + + align:start position:0% +other. And I don't know if everybody +notices that here, but it was really + + align:start position:0% +notices that here, but it was really + + + align:start position:0% +notices that here, but it was really +striking to me + + align:start position:0% + + + + align:start position:0% + +today. And so, yes, you're right. You're + + align:start position:0% +today. And so, yes, you're right. You're + + + align:start position:0% +today. And so, yes, you're right. You're +deeply right. I mean, I just I the best + + align:start position:0% +deeply right. I mean, I just I the best + + + align:start position:0% +deeply right. I mean, I just I the best +thing in my life is to go out and do + + align:start position:0% +thing in my life is to go out and do + + + align:start position:0% +thing in my life is to go out and do +field work. + + align:start position:0% + + + + align:start position:0% + +Why don't you take that one more step, + + align:start position:0% +Why don't you take that one more step, + + + align:start position:0% +Why don't you take that one more step, +right? And say, how can the + + align:start position:0% +right? And say, how can the + + + align:start position:0% +right? And say, how can the +designer take advantage of your insights + + align:start position:0% +designer take advantage of your insights + + + align:start position:0% +designer take advantage of your insights +and your taxonomies? + + align:start position:0% +and your taxonomies? + + + align:start position:0% +and your taxonomies? +Two points. One, I think it really does + + align:start position:0% +Two points. One, I think it really does + + + align:start position:0% +Two points. One, I think it really does +say that it's worth going to look. You + + align:start position:0% +say that it's worth going to look. You + + + align:start position:0% +say that it's worth going to look. You +know, the usual line about architects is + + align:start position:0% +know, the usual line about architects is + + + align:start position:0% +know, the usual line about architects is +they go traveling with their cameras and + + align:start position:0% +they go traveling with their cameras and + + + align:start position:0% +they go traveling with their cameras and +bring home + + align:start position:0% +bring home + + + align:start position:0% +bring home +slides, you know, and um and they look, + + align:start position:0% +slides, you know, and um and they look, + + + align:start position:0% +slides, you know, and um and they look, +you know, they're looking all the time + + align:start position:0% +you know, they're looking all the time + + + align:start position:0% +you know, they're looking all the time +and you know, at least, you know, at + + align:start position:0% +and you know, at least, you know, at + + + align:start position:0% +and you know, at least, you know, at +least the architects I used to know. Um + + align:start position:0% +least the architects I used to know. Um + + + align:start position:0% +least the architects I used to know. Um +and but I think it so there's one + + align:start position:0% +and but I think it so there's one + + + align:start position:0% +and but I think it so there's one +important thing that you really need to + + align:start position:0% +important thing that you really need to + + + align:start position:0% +important thing that you really need to +go look. You can't read books. Books and + + align:start position:0% +go look. You can't read books. Books and + + + align:start position:0% +go look. You can't read books. Books and +pictures will teach you nothing unless + + align:start position:0% +pictures will teach you nothing unless + + + align:start position:0% +pictures will teach you nothing unless +you get hit in the face. I would + + align:start position:0% +you get hit in the face. I would + + + align:start position:0% +you get hit in the face. I would +maintain they teach you a lot but they + + align:start position:0% +maintain they teach you a lot but they + + + align:start position:0% +maintain they teach you a lot but they +don't teach you the deep things. All + + align:start position:0% +don't teach you the deep things. All + + + align:start position:0% +don't teach you the deep things. All +right. So that's one remark which is not + + align:start position:0% +right. So that's one remark which is not + + + align:start position:0% +right. So that's one remark which is not +the not what you asked but I mean to say + + align:start position:0% +the not what you asked but I mean to say + + + align:start position:0% +the not what you asked but I mean to say +that is probably not surprising to + + align:start position:0% +that is probably not surprising to + + + align:start position:0% +that is probably not surprising to +professors of design. You know the + + align:start position:0% +professors of design. You know the + + + align:start position:0% +professors of design. You know the +students that's what you you tell them + + align:start position:0% +students that's what you you tell them + + + align:start position:0% +students that's what you you tell them +go do fieldwork. + + align:start position:0% +go do fieldwork. + + + align:start position:0% +go do fieldwork. +Um the other point is that if I'm lucky + + align:start position:0% +Um the other point is that if I'm lucky + + + align:start position:0% +Um the other point is that if I'm lucky +what I do is make it impossible people + + align:start position:0% +what I do is make it impossible people + + + align:start position:0% +what I do is make it impossible people +not to see things. Usually after I've + + align:start position:0% +not to see things. Usually after I've + + + align:start position:0% +not to see things. Usually after I've +shown them, I put up an exhibit of + + align:start position:0% +shown them, I put up an exhibit of + + + align:start position:0% +shown them, I put up an exhibit of +something like the storefront churches, + + align:start position:0% +something like the storefront churches, + + + align:start position:0% +something like the storefront churches, +the typical remark I get is my they + + align:start position:0% +the typical remark I get is my they + + + align:start position:0% +the typical remark I get is my they +said, "My god, now they're + + align:start position:0% +said, "My god, now they're + + + align:start position:0% +said, "My god, now they're +everywhere." Because you've + + align:start position:0% +everywhere." Because you've + + + align:start position:0% +everywhere." Because you've +systematically learned not to see things + + align:start position:0% +systematically learned not to see things + + + align:start position:0% +systematically learned not to see things +and once you are sort of they become + + align:start position:0% +and once you are sort of they become + + + align:start position:0% +and once you are sort of they become +topical, what's the word? There's a word + + align:start position:0% +topical, what's the word? There's a word + + + align:start position:0% +topical, what's the word? There's a word +that they use topic + + align:start position:0% +that they use topic + + + align:start position:0% +that they use topic +um salient, but there's a nicer word + + align:start position:0% +um salient, but there's a nicer word + + + align:start position:0% +um salient, but there's a nicer word +than that. essentially when they become + + align:start position:0% +than that. essentially when they become + + + align:start position:0% +than that. essentially when they become +topics for discussion, people then start + + align:start position:0% +topics for discussion, people then start + + + align:start position:0% +topics for discussion, people then start +seeing + + align:start position:0% +seeing + + + align:start position:0% +seeing +things. And one of the major purposes of + + align:start position:0% +things. And one of the major purposes of + + + align:start position:0% +things. And one of the major purposes of +the work I do is to make people see + + align:start position:0% +the work I do is to make people see + + + align:start position:0% +the work I do is to make people see +things that are I mean, I told you I'm + + align:start position:0% +things that are I mean, I told you I'm + + + align:start position:0% +things that are I mean, I told you I'm +photo photographing + + align:start position:0% +photo photographing + + + align:start position:0% +photo photographing +mosses, you know, you know, in the + + align:start position:0% +mosses, you know, you know, in the + + + align:start position:0% +mosses, you know, you know, in the +cracks. And I I have a feeling it might + + align:start position:0% +cracks. And I I have a feeling it might + + + align:start position:0% +cracks. And I I have a feeling it might +be interesting, but it might not be. I + + align:start position:0% +be interesting, but it might not be. I + + + align:start position:0% +be interesting, but it might not be. I +haven't found a useful botist yet. Uh + + align:start position:0% +haven't found a useful botist yet. Uh + + + align:start position:0% +haven't found a useful botist yet. Uh +there's lots of people by the way if you + + align:start position:0% +there's lots of people by the way if you + + + align:start position:0% +there's lots of people by the way if you +care about something called roadside + + align:start position:0% +care about something called roadside + + + align:start position:0% +care about something called roadside +ecology where people worry about um you + + align:start position:0% +ecology where people worry about um you + + + align:start position:0% +ecology where people worry about um you +know what happens on roads and there's + + align:start position:0% +know what happens on roads and there's + + + align:start position:0% +know what happens on roads and there's +lots of money for it but this is in + + align:start position:0% +lots of money for it but this is in + + + align:start position:0% +lots of money for it but this is in +cities you know and there I found one + + align:start position:0% +cities you know and there I found one + + + align:start position:0% +cities you know and there I found one +essay on mosses in cities but once + + align:start position:0% +essay on mosses in cities but once + + + align:start position:0% +essay on mosses in cities but once +people hear about this they can't help + + align:start position:0% +people hear about this they can't help + + + align:start position:0% +people hear about this they can't help +but + + align:start position:0% +but + + + align:start position:0% +but +see especially if I have something + + align:start position:0% +see especially if I have something + + + align:start position:0% +see especially if I have something +interesting to say which at the moment I + + align:start position:0% +interesting to say which at the moment I + + + align:start position:0% +interesting to say which at the moment I +don't. Does that answer a little bit? I + + align:start position:0% +don't. Does that answer a little bit? I + + + align:start position:0% +don't. Does that answer a little bit? I +mean I don't in other words I don't know + + align:start position:0% +mean I don't in other words I don't know + + + align:start position:0% +mean I don't in other words I don't know +if anything I say is so important as the + + align:start position:0% +if anything I say is so important as the + + + align:start position:0% +if anything I say is so important as the +fact that it's there that's + + align:start position:0% +fact that it's there that's + + + align:start position:0% +fact that it's there that's +unavoidable you know it's just + + align:start position:0% +unavoidable you know it's just + + + align:start position:0% +unavoidable you know it's just +unavoidable + + align:start position:0% + + + + align:start position:0% + +um or when I talk about stuff um worship + + align:start position:0% +um or when I talk about stuff um worship + + + align:start position:0% +um or when I talk about stuff um worship +uh it + + align:start position:0% + + + + align:start position:0% + +doesn't there's nothing profound there + + align:start position:0% +doesn't there's nothing profound there + + + align:start position:0% +doesn't there's nothing profound there +it's just that people don't take it + + align:start position:0% +it's just that people don't take it + + + align:start position:0% +it's just that people don't take it +seriously if that's what I mean you know + + align:start position:0% +seriously if that's what I mean you know + + + align:start position:0% +seriously if that's what I mean you know +they sort dismiss it unless they're + + align:start position:0% +they sort dismiss it unless they're + + + align:start position:0% +they sort dismiss it unless they're +professor of religion or a believer. But + + align:start position:0% +professor of religion or a believer. But + + + align:start position:0% +professor of religion or a believer. But +there's other places ways to take it + + align:start position:0% +there's other places ways to take it + + + align:start position:0% +there's other places ways to take it +seriously. + + align:start position:0% + + + + align:start position:0% + +Um I think that's the most useful thing + + align:start position:0% +Um I think that's the most useful thing + + + align:start position:0% +Um I think that's the most useful thing +or that you see the other way to put + + align:start position:0% +or that you see the other way to put + + + align:start position:0% +or that you see the other way to put +this is that what you have to learn as a + + align:start position:0% +this is that what you have to learn as a + + + align:start position:0% +this is that what you have to learn as a +designer is that things just don't + + align:start position:0% +designer is that things just don't + + + align:start position:0% +designer is that things just don't +happen. They're happening for a set of + + align:start position:0% +happen. They're happening for a set of + + + align:start position:0% +happen. They're happening for a set of +usually political, sociological, + + align:start position:0% +usually political, sociological, + + + align:start position:0% +usually political, sociological, +economic reasons. And there there's a + + align:start position:0% +economic reasons. And there there's a + + + align:start position:0% +economic reasons. And there there's a +reason why the storefront churches are + + align:start position:0% +reason why the storefront churches are + + + align:start position:0% +reason why the storefront churches are +where they are. And there's a story + + align:start position:0% +where they are. And there's a story + + + align:start position:0% +where they are. And there's a story +behind that. And so it's not just things + + align:start position:0% +behind that. And so it's not just things + + + align:start position:0% +behind that. And so it's not just things +happen, they happen in a coherent way, + + align:start position:0% +happen, they happen in a coherent way, + + + align:start position:0% +happen, they happen in a coherent way, +in a meaningful + + align:start position:0% +in a meaningful + + + align:start position:0% +in a meaningful +way. And that changes things because + + align:start position:0% +way. And that changes things because + + + align:start position:0% +way. And that changes things because +then it becomes a linked set of motives. + + align:start position:0% +then it becomes a linked set of motives. + + + align:start position:0% +then it becomes a linked set of motives. +And what you see and how it works are + + align:start position:0% + + + + align:start position:0% + +related. And that seems to be a deeply + + align:start position:0% +related. And that seems to be a deeply + + + align:start position:0% +related. And that seems to be a deeply +important thing for people who do do + + align:start position:0% +important thing for people who do do + + + align:start position:0% +important thing for people who do do +design. They know this sort of. They're + + align:start position:0% +design. They know this sort of. They're + + + align:start position:0% +design. They know this sort of. They're +not stupid. It's just not part of + + align:start position:0% +not stupid. It's just not part of + + + align:start position:0% +not stupid. It's just not part of +their breadandbut way of thinking in + + align:start position:0% +their breadandbut way of thinking in + + + align:start position:0% +their breadandbut way of thinking in +general. That's why city planners and + + align:start position:0% +general. That's why city planners and + + + align:start position:0% +general. That's why city planners and +designers are often so very + + align:start position:0% + + + + align:start position:0% + +different + + align:start position:0% +different + + + align:start position:0% +different +anything one final thought in that + + align:start position:0% +anything one final thought in that + + + align:start position:0% +anything one final thought in that +respect what you're doing for us is + + align:start position:0% +respect what you're doing for us is + + + align:start position:0% +respect what you're doing for us is +saying you must attend to greater number + + align:start position:0% +saying you must attend to greater number + + + align:start position:0% +saying you must attend to greater number +of + + align:start position:0% +of + + + align:start position:0% +of +conditions and + + align:start position:0% +conditions and + + + align:start position:0% +conditions and +everything you've got to be reasonably + + align:start position:0% +everything you've got to be reasonably + + + align:start position:0% +everything you've got to be reasonably +flat your + + align:start position:0% +flat your + + + align:start position:0% +flat your +priorities with + + align:start position:0% + + + + align:start position:0% + +many + + align:start position:0% + + + + align:start position:0% + +deceased. So + + align:start position:0% +deceased. So + + + align:start position:0% +deceased. So +it's number + + align:start position:0% + + + + align:start position:0% + +the gentleman over there was saying to + + align:start position:0% +the gentleman over there was saying to + + + align:start position:0% +the gentleman over there was saying to +me well could you do it with everything? + + align:start position:0% +me well could you do it with everything? + + + align:start position:0% +me well could you do it with everything? +I think it's not true that everything + + align:start position:0% +I think it's not true that everything + + + align:start position:0% +I think it's not true that everything +counts but the idea is to learn a few + + align:start position:0% +counts but the idea is to learn a few + + + align:start position:0% +counts but the idea is to learn a few +more things. I mean, you can't tell + + align:start position:0% +more things. I mean, you can't tell + + + align:start position:0% +more things. I mean, you can't tell +people everything counts because that's + + align:start position:0% +people everything counts because that's + + + align:start position:0% +people everything counts because that's +just + + align:start position:0% +just + + + align:start position:0% +just +disastrous. You know, that's that's the + + align:start position:0% +disastrous. You know, that's that's the + + + align:start position:0% +disastrous. You know, that's that's the +kind of advice that that's paralyzing. + + align:start position:0% +kind of advice that that's paralyzing. + + + align:start position:0% +kind of advice that that's paralyzing. +But to give them more things that + + align:start position:0% +But to give them more things that + + + align:start position:0% +But to give them more things that +count is just + + align:start position:0% +count is just + + + align:start position:0% +count is just +amazing. And if you choose the things + + align:start position:0% +amazing. And if you choose the things + + + align:start position:0% +amazing. And if you choose the things +with some + + align:start position:0% +with some + + + align:start position:0% +with some +care, you know, it could be this Morse + + align:start position:0% +care, you know, it could be this Morse + + + align:start position:0% +care, you know, it could be this Morse +idea is ridiculous and stupid, you know, + + align:start position:0% +idea is ridiculous and stupid, you know, + + + align:start position:0% +idea is ridiculous and stupid, you know, +that I really can't go any place with + + align:start position:0% +that I really can't go any place with + + + align:start position:0% +that I really can't go any place with +it. Uh, but we'll see. And the sound + + align:start position:0% +it. Uh, but we'll see. And the sound + + + align:start position:0% +it. Uh, but we'll see. And the sound +stuff I don't think will be stupid but + + align:start position:0% +stuff I don't think will be stupid but + + + align:start position:0% +stuff I don't think will be stupid but +you know it might turn out not to be + + align:start position:0% + + + + align:start position:0% + +productive. It's an empirical it's + + align:start position:0% +productive. It's an empirical it's + + + align:start position:0% +productive. It's an empirical it's +a intellectual question. Can you make + + align:start position:0% +a intellectual question. Can you make + + + align:start position:0% +a intellectual question. Can you make +something of it? + + align:start position:0% + + + + align:start position:0% + +Yeah. I mean you know it it my thing I'm + + align:start position:0% +Yeah. I mean you know it it my thing I'm + + + align:start position:0% +Yeah. I mean you know it it my thing I'm +right now thinking about is what does it + + align:start position:0% +right now thinking about is what does it + + + align:start position:0% +right now thinking about is what does it +sound like to be in your apartment with + + align:start position:0% +sound like to be in your apartment with + + + align:start position:0% +sound like to be in your apartment with +traffic + + align:start position:0% +traffic + + + align:start position:0% +traffic +outside and how you don't hear it. Where + + align:start position:0% +outside and how you don't hear it. Where + + + align:start position:0% +outside and how you don't hear it. Where +I live, there's always accidents and + + align:start position:0% +I live, there's always accidents and + + + align:start position:0% +I live, there's always accidents and +most of the time you hear a crash, you + + align:start position:0% +most of the time you hear a crash, you + + + align:start position:0% +most of the time you hear a crash, you +don't do anything. You go on, you know, + + align:start position:0% +don't do anything. You go on, you know, + + + align:start position:0% +don't do anything. You go on, you know, +after a while. It's + + align:start position:0% +after a while. It's + + + align:start position:0% +after a while. It's +interesting. + + align:start position:0% +interesting. + + + align:start position:0% +interesting. +Um, I don't know what I'm talking about + + align:start position:0% +Um, I don't know what I'm talking about + + + align:start position:0% +Um, I don't know what I'm talking about +here, but hopefully in a year I will. My + + align:start position:0% +here, but hopefully in a year I will. My + + + align:start position:0% +here, but hopefully in a year I will. My +friends who do sound design and sound + + align:start position:0% +friends who do sound design and sound + + + align:start position:0% +friends who do sound design and sound +editing for films, they're very + + align:start position:0% +editing for films, they're very + + + align:start position:0% +editing for films, they're very +articulate about using + + align:start position:0% +articulate about using + + + align:start position:0% +articulate about using +sound. They know exactly what they want. + + align:start position:0% +sound. They know exactly what they want. + + + align:start position:0% +sound. They know exactly what they want. +Not exactly, but you know, for them it's + + align:start position:0% +Not exactly, but you know, for them it's + + + align:start position:0% +Not exactly, but you know, for them it's +it's a it's a vocabulary rich laden + + align:start position:0% +it's a it's a vocabulary rich laden + + + align:start position:0% +it's a it's a vocabulary rich laden +thing, but and their thing is to create + + align:start position:0% +thing, but and their thing is to create + + + align:start position:0% +thing, but and their thing is to create +an ordinary feeling. You know what I + + align:start position:0% +an ordinary feeling. You know what I + + + align:start position:0% +an ordinary feeling. You know what I +mean? They're trying remember their + + align:start position:0% +mean? They're trying remember their + + + align:start position:0% +mean? They're trying remember their +problem is there is no good ordinary + + align:start position:0% +problem is there is no good ordinary + + + align:start position:0% +problem is there is no good ordinary +sound to be recorded. They have to put + + align:start position:0% +sound to be recorded. They have to put + + + align:start position:0% +sound to be recorded. They have to put +it all in because the background sound + + align:start position:0% +it all in because the background sound + + + align:start position:0% +it all in because the background sound +is never + + align:start position:0% +is never + + + align:start position:0% +is never +right. you know, the background sound in + + align:start position:0% +right. you know, the background sound in + + + align:start position:0% +right. you know, the background sound in +the in the in the in the uh studio or + + align:start position:0% +the in the in the in the uh studio or + + + align:start position:0% +the in the in the in the uh studio or +even on on uh on stage, they're always + + align:start position:0% +even on on uh on stage, they're always + + + align:start position:0% +even on on uh on stage, they're always +they're completely artificial about + + align:start position:0% +they're completely artificial about + + + align:start position:0% +they're completely artificial about +it. And uh and think of lighting in + + align:start position:0% +it. And uh and think of lighting in + + + align:start position:0% +it. And uh and think of lighting in +theater, + + align:start position:0% +theater, + + + align:start position:0% +theater, +right? Where it's all, you know, let + + align:start position:0% +right? Where it's all, you know, let + + + align:start position:0% +right? Where it's all, you know, let +there be light. Each each lighting + + align:start position:0% +there be light. Each each lighting + + + align:start position:0% +there be light. Each each lighting +designer is like God. + + align:start position:0% + + + + align:start position:0% + +There were some questions that did you + + align:start position:0% +There were some questions that did you + + + align:start position:0% +There were some questions that did you +have a question before? Yeah. Yeah. + + align:start position:0% +have a question before? Yeah. Yeah. + + + align:start position:0% +have a question before? Yeah. Yeah. +Well, I was I was going to ask I think + + align:start position:0% +Well, I was I was going to ask I think + + + align:start position:0% +Well, I was I was going to ask I think +you sort of revealed the answer, but I + + align:start position:0% +you sort of revealed the answer, but I + + + align:start position:0% +you sort of revealed the answer, but I +was I was going to ask about your + + align:start position:0% +was I was going to ask about your + + + align:start position:0% +was I was going to ask about your +comment when you said, you know, perhaps + + align:start position:0% +comment when you said, you know, perhaps + + + align:start position:0% +comment when you said, you know, perhaps +800 makes a better argument than 600. + + align:start position:0% +800 makes a better argument than 600. + + + align:start position:0% +800 makes a better argument than 600. +But what is your argument? But it sounds + + align:start position:0% +But what is your argument? But it sounds + + + align:start position:0% +But what is your argument? But it sounds +like your argument is this exists. Um + + align:start position:0% +like your argument is this exists. Um + + + align:start position:0% +like your argument is this exists. Um +you give us the future. Well, no. That + + align:start position:0% +you give us the future. Well, no. That + + + align:start position:0% +you give us the future. Well, no. That +was a joke partially. Probably I could + + align:start position:0% +was a joke partially. Probably I could + + + align:start position:0% +was a joke partially. Probably I could +have stopped at 600. All right. Uh I + + align:start position:0% +have stopped at 600. All right. Uh I + + + align:start position:0% +have stopped at 600. All right. Uh I +couldn't have stopped at 100. I know + + align:start position:0% +couldn't have stopped at 100. I know + + + align:start position:0% +couldn't have stopped at 100. I know +that. + + align:start position:0% +that. + + + align:start position:0% +that. +And I could have could I have stopped at + + align:start position:0% +And I could have could I have stopped at + + + align:start position:0% +And I could have could I have stopped at +400? Probably. All right. But there were + + align:start position:0% +400? Probably. All right. But there were + + + align:start position:0% +400? Probably. All right. But there were +questions of represent + + align:start position:0% +questions of represent + + + align:start position:0% +questions of represent +representativeness. I had it wasn't on + + align:start position:0% +representativeness. I had it wasn't on + + + align:start position:0% +representativeness. I had it wasn't on +400, but I needed some other parts of + + align:start position:0% +400, but I needed some other parts of + + + align:start position:0% +400, but I needed some other parts of +the + + align:start position:0% +the + + + align:start position:0% +the +city. I had a feel like I was running + + align:start position:0% +city. I had a feel like I was running + + + align:start position:0% +city. I had a feel like I was running +out of interesting cases. + + align:start position:0% +out of interesting cases. + + + align:start position:0% +out of interesting cases. +I mean, I've gone to about 40 um clothes + + align:start position:0% +I mean, I've gone to about 40 um clothes + + + align:start position:0% +I mean, I've gone to about 40 um clothes +manufacturers in Los Angeles, you know, + + align:start position:0% +manufacturers in Los Angeles, you know, + + + align:start position:0% +manufacturers in Los Angeles, you know, +where they do sewing or cutting, maybe + + align:start position:0% +where they do sewing or cutting, maybe + + + align:start position:0% +where they do sewing or cutting, maybe +more. All right. At some point, it + + align:start position:0% +more. All right. At some point, it + + + align:start position:0% +more. All right. At some point, it +doesn't seem like I'm going to learn + + align:start position:0% +doesn't seem like I'm going to learn + + + align:start position:0% +doesn't seem like I'm going to learn +anymore. I went to + + align:start position:0% + + + + align:start position:0% + +maybe, let me give you another example. + + align:start position:0% +maybe, let me give you another example. + + + align:start position:0% +maybe, let me give you another example. +I went to one very large foundry where + + align:start position:0% +I went to one very large foundry where + + + align:start position:0% +I went to one very large foundry where +they make things like for Saturn rockets + + align:start position:0% +they make things like for Saturn rockets + + + align:start position:0% +they make things like for Saturn rockets +the the round parts the thing that holds + + align:start position:0% +the the round parts the thing that holds + + + align:start position:0% +the the round parts the thing that holds +it the bands and so forth and that's + + align:start position:0% +it the bands and so forth and that's + + + align:start position:0% +it the bands and so forth and that's +very high purity metal you know you can + + align:start position:0% +very high purity metal you know you can + + + align:start position:0% +very high purity metal you know you can +imagine and it has the biggest you know + + align:start position:0% +imagine and it has the biggest you know + + + align:start position:0% +imagine and it has the biggest you know +forge in the west coast or maybe in the + + align:start position:0% +forge in the west coast or maybe in the + + + align:start position:0% +forge in the west coast or maybe in the +world whatnot and it might be nice to go + + align:start position:0% +world whatnot and it might be nice to go + + + align:start position:0% +world whatnot and it might be nice to go +to another one but one's enough probably + + align:start position:0% +to another one but one's enough probably + + + align:start position:0% +to another one but one's enough probably +of that on the other hand there is a + + align:start position:0% +of that on the other hand there is a + + + align:start position:0% +of that on the other hand there is a +foundry in downtown Los Angeles, which + + align:start position:0% +foundry in downtown Los Angeles, which + + + align:start position:0% +foundry in downtown Los Angeles, which +my favorite one called Alphacast. And + + align:start position:0% +my favorite one called Alphacast. And + + + align:start position:0% +my favorite one called Alphacast. And +what do they make? They make things like + + align:start position:0% +what do they make? They make things like + + + align:start position:0% +what do they make? They make things like +light poles, you know, and those + + align:start position:0% +light poles, you know, and those + + + align:start position:0% +light poles, you know, and those +decorated things out of cast aluminum + + align:start position:0% +decorated things out of cast aluminum + + + align:start position:0% +decorated things out of cast aluminum +and all right. And I'm convinced that + + align:start position:0% +and all right. And I'm convinced that + + + align:start position:0% +and all right. And I'm convinced that +what I need to do there is not go to + + align:start position:0% +what I need to do there is not go to + + + align:start position:0% +what I need to do there is not go to +other foundaries, but study this one + + align:start position:0% +other foundaries, but study this one + + + align:start position:0% +other foundaries, but study this one +better, more because the men there, + + align:start position:0% +better, more because the men there, + + + align:start position:0% +better, more because the men there, +first of all, they know me finally. You + + align:start position:0% +first of all, they know me finally. You + + + align:start position:0% +first of all, they know me finally. You +know, they're used to this guy who keeps + + align:start position:0% +know, they're used to this guy who keeps + + + align:start position:0% +know, they're used to this guy who keeps +showing up. But they they're friendly + + align:start position:0% +showing up. But they they're friendly + + + align:start position:0% +showing up. But they they're friendly +and they work together and they, you + + align:start position:0% +and they work together and they, you + + + align:start position:0% +and they work together and they, you +know, it's a very coordinated business. + + align:start position:0% +know, it's a very coordinated business. + + + align:start position:0% +know, it's a very coordinated business. +You know, I don't know if you know that + + align:start position:0% +You know, I don't know if you know that + + + align:start position:0% +You know, I don't know if you know that +many kinds of work are are really quite + + align:start position:0% +many kinds of work are are really quite + + + align:start position:0% +many kinds of work are are really quite +dangerous. For example, working at the + + align:start position:0% +dangerous. For example, working at the + + + align:start position:0% +dangerous. For example, working at the +ports is extremely dangerous because all + + align:start position:0% +ports is extremely dangerous because all + + + align:start position:0% +ports is extremely dangerous because all +you need to do is have a uh a um + + align:start position:0% +you need to do is have a uh a um + + + align:start position:0% +you need to do is have a uh a um +container fall on + + align:start position:0% +container fall on + + + align:start position:0% +container fall on +you splat. All right? And this + + align:start position:0% +you splat. All right? And this + + + align:start position:0% +you splat. All right? And this +happens. So, um it's um so let me give + + align:start position:0% +happens. So, um it's um so let me give + + + align:start position:0% +happens. So, um it's um so let me give +an example of that. And I I had a guy + + align:start position:0% +an example of that. And I I had a guy + + + align:start position:0% +an example of that. And I I had a guy +who took me to the ports. He was a high + + align:start position:0% +who took me to the ports. He was a high + + + align:start position:0% +who took me to the ports. He was a high +guy in the ILW, International Longshore + + align:start position:0% +guy in the ILW, International Longshore + + + align:start position:0% +guy in the ILW, International Longshore +Workers, Longshore and Warehouse Workers + + align:start position:0% +Workers, Longshore and Warehouse Workers + + + align:start position:0% +Workers, Longshore and Warehouse Workers +Union, which is the West Coast Union. + + align:start position:0% +Union, which is the West Coast Union. + + + align:start position:0% +Union, which is the West Coast Union. +It's much less corrupt than the East + + align:start position:0% +It's much less corrupt than the East + + + align:start position:0% +It's much less corrupt than the East +Coast one. All right. Harry Bridges, you + + align:start position:0% +Coast one. All right. Harry Bridges, you + + + align:start position:0% +Coast one. All right. Harry Bridges, you +ever hear of him? He was he he was an + + align:start position:0% +ever hear of him? He was he he was an + + + align:start position:0% +ever hear of him? He was he he was an +Australian guy. He was a communist. You + + align:start position:0% +Australian guy. He was a communist. You + + + align:start position:0% +Australian guy. He was a communist. You +can imagine how popular he was at a + + align:start position:0% +can imagine how popular he was at a + + + align:start position:0% +can imagine how popular he was at a +certain time. He was the leader. All + + align:start position:0% +certain time. He was the leader. All + + + align:start position:0% +certain time. He was the leader. All +right. And worth knowing about. And so + + align:start position:0% +right. And worth knowing about. And so + + + align:start position:0% +right. And worth knowing about. And so +so um Dominic took me around. Dominic's + + align:start position:0% +so um Dominic took me around. Dominic's + + + align:start position:0% +so um Dominic took me around. Dominic's +father was the founder, one of the + + align:start position:0% +father was the founder, one of the + + + align:start position:0% +father was the founder, one of the +founders of the union, I'm told. And + + align:start position:0% +founders of the union, I'm told. And + + + align:start position:0% +founders of the union, I'm told. And +Dominic is about + + align:start position:0% +Dominic is about + + + align:start position:0% +Dominic is about +72. He still works at the port. He's + + align:start position:0% +72. He still works at the port. He's + + + align:start position:0% +72. He still works at the port. He's +also a professor at a local community + + align:start position:0% +also a professor at a local community + + + align:start position:0% +also a professor at a local community +college. And so we went to uh about + + align:start position:0% +college. And so we went to uh about + + + align:start position:0% +college. And so we went to uh about +seven different kinds of ships, roll on, + + align:start position:0% +seven different kinds of ships, roll on, + + + align:start position:0% +seven different kinds of ships, roll on, +roll off, uh so-called bulk loaders. I + + align:start position:0% +roll off, uh so-called bulk loaders. I + + + align:start position:0% +roll off, uh so-called bulk loaders. I +could give you the names of all these. + + align:start position:0% +could give you the names of all these. + + + align:start position:0% +could give you the names of all these. +All right? And he wanted me to see it. + + align:start position:0% +All right? And he wanted me to see it. + + + align:start position:0% +All right? And he wanted me to see it. +Now, you know, he had his own agenda. He + + align:start position:0% +Now, you know, he had his own agenda. He + + + align:start position:0% +Now, you know, he had his own agenda. He +wanted me to show the men at work and be + + align:start position:0% +wanted me to show the men at work and be + + + align:start position:0% +wanted me to show the men at work and be +sympathetic to them, but I come from the + + align:start position:0% +sympathetic to them, but I come from the + + + align:start position:0% +sympathetic to them, but I come from the +background where that's free. So that + + align:start position:0% +background where that's free. So that + + + align:start position:0% +background where that's free. So that +wasn't he didn't have to work on me. But + + align:start position:0% +wasn't he didn't have to work on me. But + + + align:start position:0% +wasn't he didn't have to work on me. But +um and so I was able to go to, you know, + + align:start position:0% +um and so I was able to go to, you know, + + + align:start position:0% +um and so I was able to go to, you know, +seven or eight + + align:start position:0% +seven or eight + + + align:start position:0% +seven or eight +sites. Um should I go to more is a + + align:start position:0% +sites. Um should I go to more is a + + + align:start position:0% +sites. Um should I go to more is a +question. I don't think so. All right. + + align:start position:0% +question. I don't think so. All right. + + + align:start position:0% +question. I don't think so. All right. +But it might be interesting, but I'm not + + align:start position:0% +But it might be interesting, but I'm not + + + align:start position:0% +But it might be interesting, but I'm not +going to cuz it was hard to gain access. + + align:start position:0% +going to cuz it was hard to gain access. + + + align:start position:0% +going to cuz it was hard to gain access. +But I went to every main kind of ship, + + align:start position:0% +But I went to every main kind of ship, + + + align:start position:0% +But I went to every main kind of ship, +you know, freight ship from container + + align:start position:0% +you know, freight ship from container + + + align:start position:0% +you know, freight ship from container +ships. Oh, I let me show you this with + + align:start position:0% +ships. Oh, I let me show you this with + + + align:start position:0% +ships. Oh, I let me show you this with +just for the f just to + + align:start position:0% +just for the f just to + + + align:start position:0% +just for the f just to +brag. Um, oh god, these problem with all + + align:start position:0% +brag. Um, oh god, these problem with all + + + align:start position:0% +brag. Um, oh god, these problem with all +this stuff is that we've worked so hard + + align:start position:0% +this stuff is that we've worked so hard + + + align:start position:0% +this stuff is that we've worked so hard +at producing this that I can't find it. + + align:start position:0% +at producing this that I can't find it. + + + align:start position:0% +at producing this that I can't find it. +Let me get rid of some of these. I want + + align:start position:0% +Let me get rid of some of these. I want + + + align:start position:0% +Let me get rid of some of these. I want +to show you uh one other + + align:start position:0% +to show you uh one other + + + align:start position:0% +to show you uh one other +thing. Yeah, these are photographs I + + align:start position:0% +thing. Yeah, these are photographs I + + + align:start position:0% +thing. Yeah, these are photographs I +took. Where are they? Oh god. Come on. + + align:start position:0% +took. Where are they? Oh god. Come on. + + + align:start position:0% +took. Where are they? Oh god. Come on. +Are they here? No. Here. These + + align:start position:0% +Are they here? No. Here. These + + + align:start position:0% +Are they here? No. Here. These +photographs here are you see them in the + + align:start position:0% +photographs here are you see them in the + + + align:start position:0% +photographs here are you see them in the +poster. This is a couple actually. They + + align:start position:0% +poster. This is a couple actually. They + + + align:start position:0% +poster. This is a couple actually. They +met in the union hiring call. All right. + + align:start position:0% +met in the union hiring call. All right. + + + align:start position:0% +met in the union hiring call. All right. +And they are called frontmen. The things + + align:start position:0% +And they are called frontmen. The things + + + align:start position:0% +And they are called frontmen. The things +coming off the ship. This is looking + + align:start position:0% +coming off the ship. This is looking + + + align:start position:0% +coming off the ship. This is looking +into the hold of a ship. This is uh some + + align:start position:0% +into the hold of a ship. This is uh some + + + align:start position:0% +into the hold of a ship. This is uh some +of the documents that go on. This is I + + align:start position:0% +of the documents that go on. This is I + + + align:start position:0% +of the documents that go on. This is I +was I was up at 10tory high in a + + align:start position:0% +was I was up at 10tory high in a + + + align:start position:0% +was I was up at 10tory high in a +crane. That's my bragging. And it's a + + align:start position:0% +crane. That's my bragging. And it's a + + + align:start position:0% +crane. That's my bragging. And it's a +woman doing it. She's she's a crane + + align:start position:0% +woman doing it. She's she's a crane + + + align:start position:0% +woman doing it. She's she's a crane +operator. And then you ask, "How'd she + + align:start position:0% +operator. And then you ask, "How'd she + + + align:start position:0% +operator. And then you ask, "How'd she +get to be a crane operator?" There's a + + align:start position:0% +get to be a crane operator?" There's a + + + align:start position:0% +get to be a crane operator?" There's a +story. Um, these guys love their work. + + align:start position:0% +story. Um, these guys love their work. + + + align:start position:0% +story. Um, these guys love their work. +They're really terrific at stowing and + + align:start position:0% +They're really terrific at stowing and + + + align:start position:0% +They're really terrific at stowing and +untowing things. They really like doing + + align:start position:0% +untowing things. They really like doing + + + align:start position:0% +untowing things. They really like doing +their work. I mean, I met them and + + align:start position:0% +their work. I mean, I met them and + + + align:start position:0% +their work. I mean, I met them and +talked to them. + + align:start position:0% +talked to them. + + + align:start position:0% +talked to them. +Um, yeah. What's his name? Oh, I forgot + + align:start position:0% +Um, yeah. What's his name? Oh, I forgot + + + align:start position:0% +Um, yeah. What's his name? Oh, I forgot +his name. I met him see him. I kept + + align:start position:0% +his name. I met him see him. I kept + + + align:start position:0% +his name. I met him see him. I kept +meeting him at various different having + + align:start position:0% +meeting him at various different having + + + align:start position:0% +meeting him at various different having +different jobs. when they load up a + + align:start position:0% +different jobs. when they load up a + + + align:start position:0% +different jobs. when they load up a +ship, the idea is you have to make it + + align:start position:0% +ship, the idea is you have to make it + + + align:start position:0% +ship, the idea is you have to make it +sort of uniform otherwise the ship will + + align:start position:0% +sort of uniform otherwise the ship will + + + align:start position:0% +sort of uniform otherwise the ship will +tilt and which is not what you want. Uh + + align:start position:0% +tilt and which is not what you want. Uh + + + align:start position:0% +tilt and which is not what you want. Uh +this is uh the set of uh assignments at + + align:start position:0% +this is uh the set of uh assignments at + + + align:start position:0% +this is uh the set of uh assignments at +uh Disney at a Disney crew boat you know + + align:start position:0% +uh Disney at a Disney crew boat you know + + + align:start position:0% +uh Disney at a Disney crew boat you know +at a Disney cruise boat and each of the + + align:start position:0% +at a Disney cruise boat and each of the + + + align:start position:0% +at a Disney cruise boat and each of the +each of the uh different + + align:start position:0% +each of the uh different + + + align:start position:0% +each of the uh different +um kinds of uh luggage different groups + + align:start position:0% +um kinds of uh luggage different groups + + + align:start position:0% +um kinds of uh luggage different groups +of luggage has a different Disney figure + + align:start position:0% +of luggage has a different Disney figure + + + align:start position:0% +of luggage has a different Disney figure +associated with it. + + align:start position:0% +associated with it. + + + align:start position:0% +associated with it. +Um this is another one. This is guy has + + align:start position:0% +Um this is another one. This is guy has + + + align:start position:0% +Um this is another one. This is guy has +an ILWU um you know + + align:start position:0% +an ILWU um you know + + + align:start position:0% +an ILWU um you know +um tattoo and this is people waiting to + + align:start position:0% +um tattoo and this is people waiting to + + + align:start position:0% +um tattoo and this is people waiting to +find jobs. All right. + + align:start position:0% + + + + align:start position:0% + +So I don't think I would learn more by + + align:start position:0% +So I don't think I would learn more by + + + align:start position:0% +So I don't think I would learn more by +doing many more photographs but I could + + align:start position:0% +doing many more photographs but I could + + + align:start position:0% +doing many more photographs but I could +have a lot I could you know do much + + align:start position:0% +have a lot I could you know do much + + + align:start position:0% +have a lot I could you know do much +more. Have you ever read a book by Alan + + align:start position:0% +more. Have you ever read a book by Alan + + + align:start position:0% +more. Have you ever read a book by Alan +Sakula called Fish Story? Um, Sakula is + + align:start position:0% +Sakula called Fish Story? Um, Sakula is + + + align:start position:0% +Sakula called Fish Story? Um, Sakula is +something of a, let's call him a Marxist + + align:start position:0% +something of a, let's call him a Marxist + + + align:start position:0% +something of a, let's call him a Marxist +and a and a terrific photographer. And + + align:start position:0% +and a and a terrific photographer. And + + + align:start position:0% +and a and a terrific photographer. And +you ought to read it. It's all about + + align:start position:0% +you ought to read it. It's all about + + + align:start position:0% +you ought to read it. It's all about +essentially how the destruction of the + + align:start position:0% +essentially how the destruction of the + + + align:start position:0% +essentially how the destruction of the +of essentially the the ordinary the old + + align:start position:0% +of essentially the the ordinary the old + + + align:start position:0% +of essentially the the ordinary the old +labor ways destroys a certain + + align:start position:0% +labor ways destroys a certain + + + align:start position:0% +labor ways destroys a certain +society. Very smart man. A little bit + + align:start position:0% +society. Very smart man. A little bit + + + align:start position:0% +society. Very smart man. A little bit +too much for me, but that doesn't + + align:start position:0% +too much for me, but that doesn't + + + align:start position:0% +too much for me, but that doesn't +matter, you know. But the photographs + + align:start position:0% +matter, you know. But the photographs + + + align:start position:0% +matter, you know. But the photographs +are so gorgeous it gets in the way. You + + align:start position:0% +are so gorgeous it gets in the way. You + + + align:start position:0% +are so gorgeous it gets in the way. You +know, it's someone who's you if the + + align:start position:0% +know, it's someone who's you if the + + + align:start position:0% +know, it's someone who's you if the +photographs are too gorgeous, it's hard + + align:start position:0% +photographs are too gorgeous, it's hard + + + align:start position:0% +photographs are too gorgeous, it's hard +to think of people as being victimized. + + align:start position:0% +to think of people as being victimized. + + + align:start position:0% +to think of people as being victimized. +But that's another problem. But I do + + align:start position:0% +But that's another problem. But I do + + + align:start position:0% +But that's another problem. But I do +recommend it if you want to see + + align:start position:0% +recommend it if you want to see + + + align:start position:0% +recommend it if you want to see +something like that. But my purpose was + + align:start position:0% +something like that. But my purpose was + + + align:start position:0% +something like that. But my purpose was +not to do the fish story. My picture + + align:start position:0% +not to do the fish story. My picture + + + align:start position:0% +not to do the fish story. My picture +purpose was to show the context in which + + align:start position:0% +purpose was to show the context in which + + + align:start position:0% +purpose was to show the context in which +people did their work. Um I was less + + align:start position:0% +people did their work. Um I was less + + + align:start position:0% +people did their work. Um I was less +concerned about worrying about whether + + align:start position:0% +concerned about worrying about whether + + + align:start position:0% +concerned about worrying about whether +they're they're victimized or not. + + align:start position:0% +they're they're victimized or not. + + + align:start position:0% +they're they're victimized or not. +Um I don't know why I just that doesn't + + align:start position:0% +Um I don't know why I just that doesn't + + + align:start position:0% +Um I don't know why I just that doesn't +seem to me where I can do any good. I + + align:start position:0% +seem to me where I can do any good. I + + + align:start position:0% +seem to me where I can do any good. I +just don't have the kind of personality + + align:start position:0% +just don't have the kind of personality + + + align:start position:0% +just don't have the kind of personality +the right you need a certain kind of + + align:start position:0% +the right you need a certain kind of + + + align:start position:0% +the right you need a certain kind of +righteousness when you start doing that + + align:start position:0% +righteousness when you start doing that + + + align:start position:0% +righteousness when you start doing that +you know I'm on the right side of the + + align:start position:0% +you know I'm on the right side of the + + + align:start position:0% +you know I'm on the right side of the +good I tend not that I think that uh you + + align:start position:0% +good I tend not that I think that uh you + + + align:start position:0% +good I tend not that I think that uh you +know that Hitler there's a good thing to + + align:start position:0% +know that Hitler there's a good thing to + + + align:start position:0% +know that Hitler there's a good thing to +be said for Hitler or for uh you know + + align:start position:0% +be said for Hitler or for uh you know + + + align:start position:0% +be said for Hitler or for uh you know +for the head of GM but um but I I just + + align:start position:0% +for the head of GM but um but I I just + + + align:start position:0% +for the head of GM but um but I I just +don't have that kind of personality. + + align:start position:0% +don't have that kind of personality. + + + align:start position:0% +don't have that kind of personality. +Other people do and they're much better + + align:start position:0% +Other people do and they're much better + + + align:start position:0% +Other people do and they're much better +at + + align:start position:0% + + + + align:start position:0% + +it. More questions please. Yes. + + align:start position:0% + + + + align:start position:0% + +Yeah, I have a bioconical demand for an + + align:start position:0% +Yeah, I have a bioconical demand for an + + + align:start position:0% +Yeah, I have a bioconical demand for an +education as a scientist, right? M and + + align:start position:0% +education as a scientist, right? M and + + + align:start position:0% +education as a scientist, right? M and +this a different sort of empiricism + + align:start position:0% +this a different sort of empiricism + + + align:start position:0% +this a different sort of empiricism +shows you I don't mean the indexing but + + align:start position:0% +shows you I don't mean the indexing but + + + align:start position:0% +shows you I don't mean the indexing but +it's it's really specific when you say + + align:start position:0% +it's it's really specific when you say + + + align:start position:0% +it's it's really specific when you say +you know these places exist at the + + align:start position:0% +you know these places exist at the + + + align:start position:0% +you know these places exist at the +periphery and you know when talking + + align:start position:0% +periphery and you know when talking + + + align:start position:0% +periphery and you know when talking +about the power station and you sort of + + align:start position:0% +about the power station and you sort of + + + align:start position:0% +about the power station and you sort of +if you were to map them in a certain + + align:start position:0% +if you were to map them in a certain + + + align:start position:0% +if you were to map them in a certain +pattern would emerge of + + align:start position:0% +pattern would emerge of + + + align:start position:0% +pattern would emerge of +how and things like that that's an + + align:start position:0% +how and things like that that's an + + + align:start position:0% +how and things like that that's an +empiricism that's embedded in your work + + align:start position:0% +empiricism that's embedded in your work + + + align:start position:0% +empiricism that's embedded in your work +and you mentioned leader and Yeah, Mar + + align:start position:0% +and you mentioned leader and Yeah, Mar + + + align:start position:0% +and you mentioned leader and Yeah, Mar +and I I'm curious about what you think + + align:start position:0% +and I I'm curious about what you think + + + align:start position:0% +and I I'm curious about what you think +of some other Frenchmen who write about + + align:start position:0% +of some other Frenchmen who write about + + + align:start position:0% +of some other Frenchmen who write about +critical theory and everyday urbanism in + + align:start position:0% +critical theory and everyday urbanism in + + + align:start position:0% +critical theory and everyday urbanism in +critical theory. And I wonder what your + + align:start position:0% +critical theory. And I wonder what your + + + align:start position:0% +critical theory. And I wonder what your +views are on that because that's + + align:start position:0% +views are on that because that's + + + align:start position:0% +views are on that because that's +essentially + + align:start position:0% +essentially + + + align:start position:0% +essentially +non-empirical. It's I mean, no, it's + + align:start position:0% +non-empirical. It's I mean, no, it's + + + align:start position:0% +non-empirical. It's I mean, no, it's +critical and it's theoretical. It's + + align:start position:0% +critical and it's theoretical. It's + + + align:start position:0% +critical and it's theoretical. It's +meant to be empirical. It's meant to + + align:start position:0% +meant to be empirical. It's meant to + + + align:start position:0% +meant to be empirical. It's meant to +draw from examples and so forth, but + + align:start position:0% +draw from examples and so forth, but + + + align:start position:0% +draw from examples and so forth, but +it's it's I um do you think they draw + + align:start position:0% +it's it's I um do you think they draw + + + align:start position:0% +it's it's I um do you think they draw +from examples? I'm not. Let me put it + + align:start position:0% +from examples? I'm not. Let me put it + + + align:start position:0% +from examples? I'm not. Let me put it +this way. Here's your problem with me. I + + align:start position:0% +this way. Here's your problem with me. I + + + align:start position:0% +this way. Here's your problem with me. I +mean, this is this is just being honest. + + align:start position:0% +mean, this is this is just being honest. + + + align:start position:0% +mean, this is this is just being honest. +It's really terrible to admit. I was + + align:start position:0% +It's really terrible to admit. I was + + + align:start position:0% +It's really terrible to admit. I was +reading Dered Da and all those people + + align:start position:0% +reading Dered Da and all those people + + + align:start position:0% +reading Dered Da and all those people +when they were in French and only a + + align:start position:0% +when they were in French and only a + + + align:start position:0% +when they were in French and only a +little bit in English because my friends + + align:start position:0% +little bit in English because my friends + + + align:start position:0% +little bit in English because my friends +I had friends in French departments who + + align:start position:0% +I had friends in French departments who + + + align:start position:0% +I had friends in French departments who +told me, "Oh, go read this guy." And I + + align:start position:0% +told me, "Oh, go read this guy." And I + + + align:start position:0% +told me, "Oh, go read this guy." And I +was reading and I was teaching and + + align:start position:0% +was reading and I was teaching and + + + align:start position:0% +was reading and I was teaching and +reading um Haidiger before it became as + + align:start position:0% +reading um Haidiger before it became as + + + align:start position:0% +reading um Haidiger before it became as +popular as it is. Once it became + + align:start position:0% +popular as it is. Once it became + + + align:start position:0% +popular as it is. Once it became +popular, you know, in the sort of the + + align:start position:0% +popular, you know, in the sort of the + + + align:start position:0% +popular, you know, in the sort of the +the post-modernist line, I couldn't read + + align:start position:0% +the post-modernist line, I couldn't read + + + align:start position:0% +the post-modernist line, I couldn't read +the + + align:start position:0% +the + + + align:start position:0% +the +stuff, which doesn't mean I just don't + + align:start position:0% +stuff, which doesn't mean I just don't + + + align:start position:0% +stuff, which doesn't mean I just don't +have the stomach for it. Um, I don't + + align:start position:0% +have the stomach for it. Um, I don't + + + align:start position:0% +have the stomach for it. Um, I don't +have the style that's + + align:start position:0% +have the style that's + + + align:start position:0% +have the style that's +required. I mean, I just don't have I'm + + align:start position:0% +required. I mean, I just don't have I'm + + + align:start position:0% +required. I mean, I just don't have I'm +not built that way. Um, when I read + + align:start position:0% +not built that way. Um, when I read + + + align:start position:0% +not built that way. Um, when I read +Haidiger, I read him in a very + + align:start position:0% +Haidiger, I read him in a very + + + align:start position:0% +Haidiger, I read him in a very +unromanticized way, uh, in a fairly + + align:start position:0% +unromanticized way, uh, in a fairly + + + align:start position:0% +unromanticized way, uh, in a fairly +technical way. um what I learned from + + align:start position:0% +technical way. um what I learned from + + + align:start position:0% +technical way. um what I learned from +the + + align:start position:0% +the + + + align:start position:0% +the +um I mean I've learned something from + + align:start position:0% +um I mean I've learned something from + + + align:start position:0% +um I mean I've learned something from +Der Da but not very much compared to + + align:start position:0% +Der Da but not very much compared to + + + align:start position:0% +Der Da but not very much compared to +what most people seem to have learned. + + align:start position:0% +what most people seem to have learned. + + + align:start position:0% +what most people seem to have learned. +So, but you I think you have a deep + + align:start position:0% +So, but you I think you have a deep + + + align:start position:0% +So, but you I think you have a deep +question that's that's been on my mind. + + align:start position:0% +question that's that's been on my mind. + + + align:start position:0% +question that's that's been on my mind. +And anybody who has an answer, you know, + + align:start position:0% +And anybody who has an answer, you know, + + + align:start position:0% +And anybody who has an answer, you know, +be grateful for why in the world these + + align:start position:0% +be grateful for why in the world these + + + align:start position:0% +be grateful for why in the world these +three Frenchmen I keep mentioning. It's + + align:start position:0% +three Frenchmen I keep mentioning. It's + + + align:start position:0% +three Frenchmen I keep mentioning. It's +not like I spend my life, you know, + + align:start position:0% +not like I spend my life, you know, + + + align:start position:0% +not like I spend my life, you know, +where I care only for French people, but + + align:start position:0% +where I care only for French people, but + + + align:start position:0% +where I care only for French people, but +why did Marvil and Ache, right? And I + + align:start position:0% +why did Marvil and Ache, right? And I + + + align:start position:0% +why did Marvil and Ache, right? And I +asked a friend of mine um who who's the + + align:start position:0% +asked a friend of mine um who who's the + + + align:start position:0% +asked a friend of mine um who who's the +one who got me to read Dared? This is in + + align:start position:0% +one who got me to read Dared? This is in + + + align:start position:0% +one who got me to read Dared? This is in +the 70 in the he got me to read Derid + + align:start position:0% +the 70 in the he got me to read Derid + + + align:start position:0% +the 70 in the he got me to read Derid +Don in like the mid70s. All right. + + align:start position:0% +Don in like the mid70s. All right. + + + align:start position:0% +Don in like the mid70s. All right. +Before it was, you know, it was popular + + align:start position:0% +Before it was, you know, it was popular + + + align:start position:0% +Before it was, you know, it was popular +in literature, but it wasn't Gatri + + align:start position:0% +in literature, but it wasn't Gatri + + + align:start position:0% +in literature, but it wasn't Gatri +Spac's book hadn't come out and things + + align:start position:0% +Spac's book hadn't come out and things + + + align:start position:0% +Spac's book hadn't come out and things +like that. And um he said, well, it's + + align:start position:0% +like that. And um he said, well, it's + + + align:start position:0% +like that. And um he said, well, it's +partially the the the the Frenchmen are + + align:start position:0% +partially the the the the Frenchmen are + + + align:start position:0% +partially the the the the Frenchmen are +the great + + align:start position:0% +the great + + + align:start position:0% +the great +systematizers, you know, and very the + + align:start position:0% +systematizers, you know, and very the + + + align:start position:0% +systematizers, you know, and very the +rationality of it, you know, the + + align:start position:0% +rationality of it, you know, the + + + align:start position:0% +rationality of it, you know, the +systematic organization. And maybe + + align:start position:0% +systematic organization. And maybe + + + align:start position:0% +systematic organization. And maybe +that's true. All right. Now, how that + + align:start position:0% +that's true. All right. Now, how that + + + align:start position:0% +that's true. All right. Now, how that +connects with this other thread is an + + align:start position:0% +connects with this other thread is an + + + align:start position:0% +connects with this other thread is an +interesting question. And of course + + align:start position:0% +interesting question. And of course + + + align:start position:0% +interesting question. And of course +there could be several threads. I mean + + align:start position:0% +there could be several threads. I mean + + + align:start position:0% +there could be several threads. I mean +there's also a tradition in France of uh + + align:start position:0% +there's also a tradition in France of uh + + + align:start position:0% +there's also a tradition in France of uh +of + + align:start position:0% + + + + align:start position:0% + +um fantastic + + align:start position:0% +um fantastic + + + align:start position:0% +um fantastic +thinking but I've chosen these + + align:start position:0% +thinking but I've chosen these + + + align:start position:0% +thinking but I've chosen these +particular you know figures. So maybe + + align:start position:0% +particular you know figures. So maybe + + + align:start position:0% +particular you know figures. So maybe +I've chosen one thread in French thought + + align:start position:0% +I've chosen one thread in French thought + + + align:start position:0% +I've chosen one thread in French thought +but I don't uh but I'm not answering a + + align:start position:0% +but I don't uh but I'm not answering a + + + align:start position:0% +but I don't uh but I'm not answering a +question. I know that but I don't have + + align:start position:0% +question. I know that but I don't have + + + align:start position:0% +question. I know that but I don't have +anything smart to say about it. Um but I + + align:start position:0% +anything smart to say about it. Um but I + + + align:start position:0% +anything smart to say about it. Um but I +was but I was sort of struck one day. I + + align:start position:0% +was but I was sort of struck one day. I + + + align:start position:0% +was but I was sort of struck one day. I +said, "What am I doing with these French + + align:start position:0% + + + + align:start position:0% + +guys?" You know, and it's because they + + align:start position:0% +guys?" You know, and it's because they + + + align:start position:0% +guys?" You know, and it's because they +serve my + + align:start position:0% +serve my + + + align:start position:0% +serve my +purpose. But then you say, "Well, you + + align:start position:0% +purpose. But then you say, "Well, you + + + align:start position:0% +purpose. But then you say, "Well, you +know, this is not exactly an abstract + + align:start position:0% +know, this is not exactly an abstract + + + align:start position:0% +know, this is not exactly an abstract +tradition. These are people who know + + align:start position:0% +tradition. These are people who know + + + align:start position:0% +tradition. These are people who know +about each other + + align:start position:0% +about each other + + + align:start position:0% +about each other +historically." And so it's an + + align:start position:0% +historically." And so it's an + + + align:start position:0% +historically." And so it's an +interesting question. Yes, it seems that + + align:start position:0% +interesting question. Yes, it seems that + + + align:start position:0% +interesting question. Yes, it seems that +the branches sort + + align:start position:0% +the branches sort + + + align:start position:0% +the branches sort +of I'm not sure of this, but if in the + + align:start position:0% +of I'm not sure of this, but if in the + + + align:start position:0% +of I'm not sure of this, but if in the +past they they knew each other and maybe + + align:start position:0% +past they they knew each other and maybe + + + align:start position:0% +past they they knew each other and maybe +sort of the sensibility spread more into + + align:start position:0% +sort of the sensibility spread more into + + + align:start position:0% +sort of the sensibility spread more into +different streams of thought, it doesn't + + align:start position:0% +different streams of thought, it doesn't + + + align:start position:0% +different streams of thought, it doesn't +seem to sort of happen now where this + + align:start position:0% +seem to sort of happen now where this + + + align:start position:0% +seem to sort of happen now where this +sort of empirical work and sort of other + + align:start position:0% +sort of empirical work and sort of other + + + align:start position:0% +sort of empirical work and sort of other +presentation we've seen in this series + + align:start position:0% +presentation we've seen in this series + + + align:start position:0% +presentation we've seen in this series +that are empirical don't seem to borrow + + align:start position:0% +that are empirical don't seem to borrow + + + align:start position:0% +that are empirical don't seem to borrow +from there and um from where from from + + align:start position:0% +from there and um from where from from + + + align:start position:0% +from there and um from where from from +say critical theory and I I I don't I'm + + align:start position:0% +say critical theory and I I I don't I'm + + + align:start position:0% +say critical theory and I I I don't I'm +not suggesting that they should. What + + align:start position:0% +not suggesting that they should. What + + + align:start position:0% +not suggesting that they should. What +I'm interested in knowing is what what + + align:start position:0% +I'm interested in knowing is what what + + + align:start position:0% +I'm interested in knowing is what what +your view on on the intelligence of of + + align:start position:0% +your view on on the intelligence of of + + + align:start position:0% +your view on on the intelligence of of +those theories are. Well, can they feed + + align:start position:0% +those theories are. Well, can they feed + + + align:start position:0% +those theories are. Well, can they feed +into into sort of Oh, sure. No, first of + + align:start position:0% +into into sort of Oh, sure. No, first of + + + align:start position:0% +into into sort of Oh, sure. No, first of +all, there's there's a whole bunch of + + align:start position:0% +all, there's there's a whole bunch of + + + align:start position:0% +all, there's there's a whole bunch of +people who um um who you know, there's a + + align:start position:0% +people who um um who you know, there's a + + + align:start position:0% +people who um um who you know, there's a +book called uh by um Oh, God. + + align:start position:0% +book called uh by um Oh, God. + + + align:start position:0% +book called uh by um Oh, God. +She's married to a photographer. She's a + + align:start position:0% +She's married to a photographer. She's a + + + align:start position:0% +She's married to a photographer. She's a +literary critic. Um, the cover has a + + align:start position:0% +literary critic. Um, the cover has a + + + align:start position:0% +literary critic. Um, the cover has a +picture of her naked um taken by her + + align:start position:0% +picture of her naked um taken by her + + + align:start position:0% +picture of her naked um taken by her +husband. + + align:start position:0% +husband. + + + align:start position:0% +husband. +Uh, oh god, I can't think of her name. + + align:start position:0% +Uh, oh god, I can't think of her name. + + + align:start position:0% +Uh, oh god, I can't think of her name. +She's I think she's at Iowa or + + align:start position:0% +She's I think she's at Iowa or + + + align:start position:0% +She's I think she's at Iowa or +something. She's a well-known feminist + + align:start position:0% +something. She's a well-known feminist + + + align:start position:0% +something. She's a well-known feminist +critic. All right. And there are people + + align:start position:0% +critic. All right. And there are people + + + align:start position:0% +critic. All right. And there are people +who do worry about this. Remember, + + align:start position:0% +who do worry about this. Remember, + + + align:start position:0% +who do worry about this. Remember, +there's there's Look, here's what here's + + align:start position:0% +there's there's Look, here's what here's + + + align:start position:0% +there's there's Look, here's what here's +the answer to you, which is sort of the + + align:start position:0% +the answer to you, which is sort of the + + + align:start position:0% +the answer to you, which is sort of the +blunt thing. There's Susan Zontag. + + align:start position:0% +blunt thing. There's Susan Zontag. + + + align:start position:0% +blunt thing. There's Susan Zontag. +There's uh Bach who writes about you + + align:start position:0% +There's uh Bach who writes about you + + + align:start position:0% +There's uh Bach who writes about you +know photography. There's um what's his + + align:start position:0% +know photography. There's um what's his + + + align:start position:0% +know photography. There's um what's his +name? Um has a whole book on + + align:start position:0% +name? Um has a whole book on + + + align:start position:0% +name? Um has a whole book on +photography. The sociologist + + align:start position:0% +photography. The sociologist + + + align:start position:0% +photography. The sociologist +Bourju there's a whole if you want the + + align:start position:0% +Bourju there's a whole if you want the + + + align:start position:0% +Bourju there's a whole if you want the +French there's a whole bunch of these + + align:start position:0% +French there's a whole bunch of these + + + align:start position:0% +French there's a whole bunch of these +Frenchmen who do this. Why don't I quote + + align:start position:0% +Frenchmen who do this. Why don't I quote + + + align:start position:0% +Frenchmen who do this. Why don't I quote +from them you might ask right? It + + align:start position:0% +from them you might ask right? It + + + align:start position:0% +from them you might ask right? It +doesn't help me + + align:start position:0% +doesn't help me + + + align:start position:0% +doesn't help me +think. All right now and you could say + + align:start position:0% +think. All right now and you could say + + + align:start position:0% +think. All right now and you could say +well uh maybe you're you're you should + + align:start position:0% +well uh maybe you're you're you should + + + align:start position:0% +well uh maybe you're you're you should +No, my my question is not why don't you + + align:start position:0% +No, my my question is not why don't you + + + align:start position:0% +No, my my question is not why don't you +quote from them but what is your + + align:start position:0% +quote from them but what is your + + + align:start position:0% +quote from them but what is your +they don't help me do my work right + + align:start position:0% +they don't help me do my work right + + + align:start position:0% +they don't help me do my work right +right but then what is behind that + + align:start position:0% +right but then what is behind that + + + align:start position:0% +right but then what is behind that +rejection or well I don't know I mean + + align:start position:0% +rejection or well I don't know I mean + + + align:start position:0% +rejection or well I don't know I mean +sort of like asking a lady who's + + align:start position:0% +sort of like asking a lady who's + + + align:start position:0% +sort of like asking a lady who's +crossing the street why doesn't she want + + align:start position:0% +crossing the street why doesn't she want + + + align:start position:0% +crossing the street why doesn't she want +someone to help him help her um + + align:start position:0% + + + + align:start position:0% + +no because it's obviously I think no no + + align:start position:0% +no because it's obviously I think no no + + + align:start position:0% +no because it's obviously I think no no +I think it's it's aund it's a good $100 + + align:start position:0% +I think it's it's aund it's a good $100 + + + align:start position:0% +I think it's it's aund it's a good $100 +question um and Maybe not everybody is + + align:start position:0% +question um and Maybe not everybody is + + + align:start position:0% +question um and Maybe not everybody is +concerned, but you know, we know what's + + align:start position:0% +concerned, but you know, we know what's + + + align:start position:0% +concerned, but you know, we know what's +going on intellectually. There's a whole + + align:start position:0% +going on intellectually. There's a whole + + + align:start position:0% +going on intellectually. There's a whole +bunch of people who concerned about + + align:start position:0% +bunch of people who concerned about + + + align:start position:0% +bunch of people who concerned about +postmodern photography. There's a whole + + align:start position:0% +postmodern photography. There's a whole + + + align:start position:0% +postmodern photography. There's a whole +bunch of people who do read those + + align:start position:0% +bunch of people who do read those + + + align:start position:0% +bunch of people who do read those +people. All right. And you know, + + align:start position:0% +people. All right. And you know, + + + align:start position:0% +people. All right. And you know, +photographer, I mean, photographic + + align:start position:0% +photographer, I mean, photographic + + + align:start position:0% +photographer, I mean, photographic +criticism is imbued with discussions of + + align:start position:0% +criticism is imbued with discussions of + + + align:start position:0% +criticism is imbued with discussions of +about and and Susan Zantag and um and + + align:start position:0% +about and and Susan Zantag and um and + + + align:start position:0% +about and and Susan Zantag and um and +and and uh and in fact, this book, which + + align:start position:0% +and and uh and in fact, this book, which + + + align:start position:0% +and and uh and in fact, this book, which +I can't remember the title of + + align:start position:0% +I can't remember the title of + + + align:start position:0% +I can't remember the title of +is is is amusing on these kinds of + + align:start position:0% +is is is amusing on these kinds of + + + align:start position:0% +is is is amusing on these kinds of +things. Um and there must be people who + + align:start position:0% +things. Um and there must be people who + + + align:start position:0% +things. Um and there must be people who +are very much influenced by it. Um + + align:start position:0% +are very much influenced by it. Um + + + align:start position:0% +are very much influenced by it. Um +because I'm not a real photographer. + + align:start position:0% +because I'm not a real photographer. + + + align:start position:0% +because I'm not a real photographer. +That's the point. I just take pictures. + + align:start position:0% +That's the point. I just take pictures. + + + align:start position:0% +That's the point. I just take pictures. +Real + + align:start position:0% +Real + + + align:start position:0% +Real +photographers look the what I mean by + + align:start position:0% +photographers look the what I mean by + + + align:start position:0% +photographers look the what I mean by +photographer is someone who is either + + align:start position:0% +photographer is someone who is either + + + align:start position:0% +photographer is someone who is either +part of an art + + align:start position:0% +part of an art + + + align:start position:0% +part of an art +tradition or a photojournalistic + + align:start position:0% +tradition or a photojournalistic + + + align:start position:0% +tradition or a photojournalistic +tradition or maybe a commercial + + align:start position:0% +tradition or maybe a commercial + + + align:start position:0% +tradition or maybe a commercial +tradition. At best I'm part of a + + align:start position:0% +tradition. At best I'm part of a + + + align:start position:0% +tradition. At best I'm part of a +documentation + + align:start position:0% +documentation + + + align:start position:0% +documentation +tradition. All right. But most of we + + align:start position:0% +tradition. All right. But most of we + + + align:start position:0% +tradition. All right. But most of we +call the documentation + + align:start position:0% +call the documentation + + + align:start position:0% +call the documentation +photographers have been elevated to + + align:start position:0% +photographers have been elevated to + + + align:start position:0% +photographers have been elevated to +artists. Etch is an artist. Marvel is an + + align:start position:0% +artists. Etch is an artist. Marvel is an + + + align:start position:0% +artists. Etch is an artist. Marvel is an +artist. You know, I mean, there no there + + align:start position:0% +artist. You know, I mean, there no there + + + align:start position:0% +artist. You know, I mean, there no there +no second rate documentary photographers + + align:start position:0% +no second rate documentary photographers + + + align:start position:0% +no second rate documentary photographers +as far as one can tell. The ones that + + align:start position:0% +as far as one can tell. The ones that + + + align:start position:0% +as far as one can tell. The ones that +written about to do documentation are + + align:start position:0% +written about to do documentation are + + + align:start position:0% +written about to do documentation are +great artists. I mean, you know, buy + + align:start position:0% +great artists. I mean, you know, buy + + + align:start position:0% +great artists. I mean, you know, buy +this thing. I can't I'm not smart enough + + align:start position:0% +this thing. I can't I'm not smart enough + + + align:start position:0% +this thing. I can't I'm not smart enough +to handle that stuff. I don't know what + + align:start position:0% +to handle that stuff. I don't know what + + + align:start position:0% +to handle that stuff. I don't know what +to do with it. All right. I mean, I can + + align:start position:0% +to do with it. All right. I mean, I can + + + align:start position:0% +to do with it. All right. I mean, I can +like the photographs, but I'm not smart + + align:start position:0% +like the photographs, but I'm not smart + + + align:start position:0% +like the photographs, but I'm not smart +about what's a great artist. I mean, + + align:start position:0% +about what's a great artist. I mean, + + + align:start position:0% +about what's a great artist. I mean, +yes, I know that, you know, Shelley Co + + align:start position:0% +yes, I know that, you know, Shelley Co + + + align:start position:0% +yes, I know that, you know, Shelley Co +is a great artist, but I don't need + + align:start position:0% +is a great artist, but I don't need + + + align:start position:0% +is a great artist, but I don't need +we're not talking about that. And you + + align:start position:0% +we're not talking about that. And you + + + align:start position:0% +we're not talking about that. And you +know, but I mean it's a fair question to + + align:start position:0% +know, but I mean it's a fair question to + + + align:start position:0% +know, but I mean it's a fair question to +ask, but in so far + + align:start position:0% + + + + align:start position:0% + +as the these you have to go, who would I + + align:start position:0% +as the these you have to go, who would I + + + align:start position:0% +as the these you have to go, who would I +look at? + + align:start position:0% +look at? + + + align:start position:0% +look at? +Um, let me + + align:start position:0% + + + + align:start position:0% + +see. Well, I mean, Sakula is a perfect + + align:start position:0% +see. Well, I mean, Sakula is a perfect + + + align:start position:0% +see. Well, I mean, Sakula is a perfect +example of writing with a Marxist tone. + + align:start position:0% +example of writing with a Marxist tone. + + + align:start position:0% +example of writing with a Marxist tone. +And there must be a whole bunch of + + align:start position:0% +And there must be a whole bunch of + + + align:start position:0% +And there must be a whole bunch of +people, photographers, who now write + + align:start position:0% +people, photographers, who now write + + + align:start position:0% +people, photographers, who now write +with uh, you know, with a postmodernist + + align:start position:0% +with uh, you know, with a postmodernist + + + align:start position:0% +with uh, you know, with a postmodernist +uh, Frenchy tone. I just don't keep up + + align:start position:0% +uh, Frenchy tone. I just don't keep up + + + align:start position:0% +uh, Frenchy tone. I just don't keep up +with it because I can't read it. I don't + + align:start position:0% +with it because I can't read it. I don't + + + align:start position:0% +with it because I can't read it. I don't +have the brain for + + align:start position:0% +have the brain for + + + align:start position:0% +have the brain for +it. Um, it the the words go right before + + align:start position:0% +it. Um, it the the words go right before + + + align:start position:0% +it. Um, it the the words go right before +my eyes. I mean, now maybe I'm becoming + + align:start position:0% +my eyes. I mean, now maybe I'm becoming + + + align:start position:0% +my eyes. I mean, now maybe I'm becoming +an old man, you know, that's always a + + align:start position:0% +an old man, you know, that's always a + + + align:start position:0% +an old man, you know, that's always a +possibility. I am becoming an old man, + + align:start position:0% +possibility. I am becoming an old man, + + + align:start position:0% +possibility. I am becoming an old man, +but I mean, maybe I'm, you know, losing + + align:start position:0% +but I mean, maybe I'm, you know, losing + + + align:start position:0% +but I mean, maybe I'm, you know, losing +it. + + align:start position:0% +it. + + + align:start position:0% +it. +Um but I think what John deo asked me + + align:start position:0% +Um but I think what John deo asked me + + + align:start position:0% +Um but I think what John deo asked me +was a serious remark when I said I get + + align:start position:0% +was a serious remark when I said I get + + + align:start position:0% +was a serious remark when I said I get +happy you know going out in the + + align:start position:0% + + + + align:start position:0% + +field somewhere along the line I lost my + + align:start position:0% +field somewhere along the line I lost my + + + align:start position:0% +field somewhere along the line I lost my +interest in that stuff. I mean I I was + + align:start position:0% +interest in that stuff. I mean I I was + + + align:start position:0% +interest in that stuff. I mean I I was +reading an article in in technology and + + align:start position:0% +reading an article in in technology and + + + align:start position:0% +reading an article in in technology and +culture which is the society of history + + align:start position:0% +culture which is the society of history + + + align:start position:0% +culture which is the society of history +of technology magazine a marvelous + + align:start position:0% +of technology magazine a marvelous + + + align:start position:0% +of technology magazine a marvelous +article about um scanning tunning tunnel + + align:start position:0% +article about um scanning tunning tunnel + + + align:start position:0% +article about um scanning tunning tunnel +microscopy and as an instrumental + + align:start position:0% +microscopy and as an instrumental + + + align:start position:0% +microscopy and as an instrumental +community and all I could think of as + + align:start position:0% +community and all I could think of as + + + align:start position:0% +community and all I could think of as +which was wonderful stuff but I said oh + + align:start position:0% +which was wonderful stuff but I said oh + + + align:start position:0% +which was wonderful stuff but I said oh +my god they're having this argument + + align:start position:0% +my god they're having this argument + + + align:start position:0% +my god they're having this argument +internal to the discipline about what + + align:start position:0% +internal to the discipline about what + + + align:start position:0% +internal to the discipline about what +instrumental community is and who's + + align:start position:0% +instrumental community is and who's + + + align:start position:0% +instrumental community is and who's +going to get points and will it be Peter + + align:start position:0% +going to get points and will it be Peter + + + align:start position:0% +going to get points and will it be Peter +Gallison or will it be Jed Buckwald you + + align:start position:0% +Gallison or will it be Jed Buckwald you + + + align:start position:0% +Gallison or will it be Jed Buckwald you +know all people I know all of whom are + + align:start position:0% +know all people I know all of whom are + + + align:start position:0% +know all people I know all of whom are +very well thought of, but each one of + + align:start position:0% +very well thought of, but each one of + + + align:start position:0% +very well thought of, but each one of +them wants to be on top, right? You + + align:start position:0% +them wants to be on top, right? You + + + align:start position:0% +them wants to be on top, right? You +know, the m major rule is the more + + align:start position:0% +know, the m major rule is the more + + + align:start position:0% +know, the m major rule is the more +famous they are, the the more they feel + + align:start position:0% +famous they are, the the more they feel + + + align:start position:0% +famous they are, the the more they feel +like they're + + align:start position:0% +like they're + + + align:start position:0% +like they're +underrecognized. If you don't know that, + + align:start position:0% +underrecognized. If you don't know that, + + + align:start position:0% +underrecognized. If you don't know that, +that's an important + + align:start position:0% +that's an important + + + align:start position:0% +that's an important +principle. And I don't + + align:start position:0% +principle. And I don't + + + align:start position:0% +principle. And I don't +care. I mean, I'll be honest with you. I + + align:start position:0% +care. I mean, I'll be honest with you. I + + + align:start position:0% +care. I mean, I'll be honest with you. I +just think of this is all this doesn't + + align:start position:0% +just think of this is all this doesn't + + + align:start position:0% +just think of this is all this doesn't +do me any good. + + align:start position:0% +do me any good. + + + align:start position:0% +do me any good. +Now that is to admit that as an + + align:start position:0% +Now that is to admit that as an + + + align:start position:0% +Now that is to admit that as an +professor is really sinful is you know + + align:start position:0% +professor is really sinful is you know + + + align:start position:0% +professor is really sinful is you know +but I don't I mean it won't help me + + align:start position:0% +but I don't I mean it won't help me + + + align:start position:0% +but I don't I mean it won't help me +where I want to know is how did industry + + align:start position:0% +where I want to know is how did industry + + + align:start position:0% +where I want to know is how did industry +works. I want to I'll read Phil Scranton + + align:start position:0% +works. I want to I'll read Phil Scranton + + + align:start position:0% +works. I want to I'll read Phil Scranton +who writes about industrial industry and + + align:start position:0% +who writes about industrial industry and + + + align:start position:0% +who writes about industrial industry and +cities or I'll read my colleague um uh + + align:start position:0% +cities or I'll read my colleague um uh + + + align:start position:0% +cities or I'll read my colleague um uh +Greg Heis. I mean, I read his stuff + + align:start position:0% +Greg Heis. I mean, I read his stuff + + + align:start position:0% +Greg Heis. I mean, I read his stuff +religiously even though he's a friend + + align:start position:0% +religiously even though he's a friend + + + align:start position:0% +religiously even though he's a friend +because or that's a joke, but you know, + + align:start position:0% +because or that's a joke, but you know, + + + align:start position:0% +because or that's a joke, but you know, +because I learn how to think about + + align:start position:0% +because I learn how to think about + + + align:start position:0% +because I learn how to think about +things. + + align:start position:0% + + + + align:start position:0% + +So, I think that's a good place. Fine. + + align:start position:0% +So, I think that's a good place. Fine. + + + align:start position:0% +So, I think that's a good place. Fine. +All right. I mean, all good. Is that + + align:start position:0% +All right. I mean, all good. Is that + + + align:start position:0% +All right. I mean, all good. Is that +okay? Yeah. Good. All right. Thank you + + align:start position:0% +okay? Yeah. Good. All right. Thank you + + + align:start position:0% +okay? Yeah. Good. All right. Thank you +all. Thank you. + + align:start position:0% + + + + align:start position:0% + +[Applause] \ No newline at end of file diff --git a/qmCbc9dbwXU.txt b/qmCbc9dbwXU.txt new file mode 100644 index 0000000000000000000000000000000000000000..941bd1c83f1667d6f814ea1f8c1a3e3c73cd7a84 --- /dev/null +++ b/qmCbc9dbwXU.txt @@ -0,0 +1,531 @@ +align:start position:0% + +let's consider a very simple example of + + align:start position:0% +let's consider a very simple example of + + + align:start position:0% +let's consider a very simple example of +a runner in which our position function + + align:start position:0% +a runner in which our position function + + + align:start position:0% +a runner in which our position function +X of T is given as a quadratic function + + align:start position:0% +X of T is given as a quadratic function + + + align:start position:0% +X of T is given as a quadratic function +in time it will be a constant B times T + + align:start position:0% +in time it will be a constant B times T + + + align:start position:0% +in time it will be a constant B times T +squared here B is a constant now it's + + align:start position:0% +squared here B is a constant now it's + + + align:start position:0% +squared here B is a constant now it's +always important in SI units to consider + + align:start position:0% +always important in SI units to consider + + + align:start position:0% +always important in SI units to consider +what the units of this constant is + + align:start position:0% +what the units of this constant is + + + align:start position:0% +what the units of this constant is +because the position function is + + align:start position:0% +because the position function is + + + align:start position:0% +because the position function is +measured in meters and time is measured + + align:start position:0% +measured in meters and time is measured + + + align:start position:0% +measured in meters and time is measured +in seconds B is a constant and it has + + align:start position:0% +in seconds B is a constant and it has + + + align:start position:0% +in seconds B is a constant and it has +units of meters per second squared and + + align:start position:0% +units of meters per second squared and + + + align:start position:0% +units of meters per second squared and +there's an example of a runner and let's + + align:start position:0% +there's an example of a runner and let's + + + align:start position:0% +there's an example of a runner and let's +make a plot of that position function so + + align:start position:0% +make a plot of that position function so + + + align:start position:0% +make a plot of that position function so +we're going to plot X of T as a function + + align:start position:0% +we're going to plot X of T as a function + + + align:start position:0% +we're going to plot X of T as a function +of time B here let's make be a positive + + align:start position:0% +of time B here let's make be a positive + + + align:start position:0% +of time B here let's make be a positive +constant and so our function looks + + align:start position:0% +constant and so our function looks + + + align:start position:0% +constant and so our function looks +something like that now the velocity + + align:start position:0% +something like that now the velocity + + + align:start position:0% +something like that now the velocity +component of the velocity remember D of + + align:start position:0% +component of the velocity remember D of + + + align:start position:0% +component of the velocity remember D of +T is given by DX DT of this function and + + align:start position:0% +T is given by DX DT of this function and + + + align:start position:0% +T is given by DX DT of this function and +the derivative of a polynomial T squared + + align:start position:0% +the derivative of a polynomial T squared + + + align:start position:0% +the derivative of a polynomial T squared +is very simple that's just simply 2 B + + align:start position:0% +is very simple that's just simply 2 B + + + align:start position:0% +is very simple that's just simply 2 B +times T again let's look at our units + + align:start position:0% +times T again let's look at our units + + + align:start position:0% +times T again let's look at our units +because B has the units of meters per + + align:start position:0% +because B has the units of meters per + + + align:start position:0% +because B has the units of meters per +second squared and we're multiplying + + align:start position:0% +second squared and we're multiplying + + + align:start position:0% +second squared and we're multiplying +that by second we have the units of + + align:start position:0% +that by second we have the units of + + + align:start position:0% +that by second we have the units of +velocity in SI units as meters per + + align:start position:0% +velocity in SI units as meters per + + + align:start position:0% +velocity in SI units as meters per +second now 2 let's plot that function + + align:start position:0% +second now 2 let's plot that function + + + align:start position:0% +second now 2 let's plot that function +notice this is a linear function and so + + align:start position:0% +notice this is a linear function and so + + + align:start position:0% +notice this is a linear function and so +if I plotted underneath here the + + align:start position:0% +if I plotted underneath here the + + + align:start position:0% +if I plotted underneath here the +velocity as a function of time its + + align:start position:0% +velocity as a function of time its + + + align:start position:0% +velocity as a function of time its +starts off with a 0 slope remember we're + + align:start position:0% +starts off with a 0 slope remember we're + + + align:start position:0% +starts off with a 0 slope remember we're +looking our velocity at any given time + + align:start position:0% +looking our velocity at any given time + + + align:start position:0% +looking our velocity at any given time +corresponds to the slope of the tangent + + align:start position:0% +corresponds to the slope of the tangent + + + align:start position:0% +corresponds to the slope of the tangent +line to the position function and you + + align:start position:0% +line to the position function and you + + + align:start position:0% +line to the position function and you +can see that slope is increasing now you + + align:start position:0% +can see that slope is increasing now you + + + align:start position:0% +can see that slope is increasing now you +wouldn't know from this graph but if you + + align:start position:0% +wouldn't know from this graph but if you + + + align:start position:0% +wouldn't know from this graph but if you +did plot T squared it's increasing + + align:start position:0% +did plot T squared it's increasing + + + align:start position:0% +did plot T squared it's increasing +linearly and so our velocity function + + align:start position:0% +linearly and so our velocity function + + + align:start position:0% +linearly and so our velocity function +the initial slope is zero at T equals + + align:start position:0% +the initial slope is zero at T equals + + + align:start position:0% +the initial slope is zero at T equals +zero and it's increasing linearly in + + align:start position:0% +zero and it's increasing linearly in + + + align:start position:0% +zero and it's increasing linearly in +time so we'll just draw that as some + + align:start position:0% +time so we'll just draw that as some + + + align:start position:0% +time so we'll just draw that as some +linear function and the slope here + + align:start position:0% +linear function and the slope here + + + align:start position:0% +linear function and the slope here +of this function will be now the + + align:start position:0% +of this function will be now the + + + align:start position:0% +of this function will be now the +acceleration so a of T is the derivative + + align:start position:0% +acceleration so a of T is the derivative + + + align:start position:0% +acceleration so a of T is the derivative +of the component of the velocity + + align:start position:0% +of the component of the velocity + + + align:start position:0% +of the component of the velocity +function as a function of time and this + + align:start position:0% +function as a function of time and this + + + align:start position:0% +function as a function of time and this +derivative is quite easy it's just + + align:start position:0% +derivative is quite easy it's just + + + align:start position:0% +derivative is quite easy it's just +simply to be now notice those have the + + align:start position:0% +simply to be now notice those have the + + + align:start position:0% +simply to be now notice those have the +units of meters per second squared we + + align:start position:0% +units of meters per second squared we + + + align:start position:0% +units of meters per second squared we +saw our units for acceleration when we + + align:start position:0% +saw our units for acceleration when we + + + align:start position:0% +saw our units for acceleration when we +again look at the slope notice that at + + align:start position:0% +again look at the slope notice that at + + + align:start position:0% +again look at the slope notice that at +every single point the slope of the + + align:start position:0% +every single point the slope of the + + + align:start position:0% +every single point the slope of the +velocity as a function of time is a + + align:start position:0% +velocity as a function of time is a + + + align:start position:0% +velocity as a function of time is a +constant the slope here is just equal to + + align:start position:0% +constant the slope here is just equal to + + + align:start position:0% +constant the slope here is just equal to +2b and so now if we plotted our + + align:start position:0% +2b and so now if we plotted our + + + align:start position:0% +2b and so now if we plotted our +acceleration function we have this point + + align:start position:0% +acceleration function we have this point + + + align:start position:0% +acceleration function we have this point +to be and every single point has the + + align:start position:0% +to be and every single point has the + + + align:start position:0% +to be and every single point has the +same value of acceleration so here the + + align:start position:0% +same value of acceleration so here the + + + align:start position:0% +same value of acceleration so here the +acceleration is an example of constant + + align:start position:0% +acceleration is an example of constant + + + align:start position:0% +acceleration is an example of constant +acceleration and this is our simplest + + align:start position:0% +acceleration and this is our simplest + + + align:start position:0% +acceleration and this is our simplest +case notice we started with a position + + align:start position:0% +case notice we started with a position + + + align:start position:0% +case notice we started with a position +function we differentiate to get the + + align:start position:0% +function we differentiate to get the + + + align:start position:0% +function we differentiate to get the +component of the velocity and to get the + + align:start position:0% +component of the velocity and to get the + + + align:start position:0% +component of the velocity and to get the +component of the acceleration so this is + + align:start position:0% +component of the acceleration so this is + + + align:start position:0% +component of the acceleration so this is +a very simple model for a runner whose + + align:start position:0% +a very simple model for a runner whose + + + align:start position:0% +a very simple model for a runner whose +increasing speed linearly accelerating + + align:start position:0% +increasing speed linearly accelerating + + + align:start position:0% +increasing speed linearly accelerating +at a constant rate \ No newline at end of file diff --git a/rCG6r6gotZQ.txt b/rCG6r6gotZQ.txt new file mode 100644 index 0000000000000000000000000000000000000000..d3046e9b0cf629b5c08ca3af7db876d7f3221c89 --- /dev/null +++ b/rCG6r6gotZQ.txt @@ -0,0 +1,7003 @@ +align:start position:0% + +The following content is provided under + + align:start position:0% +The following content is provided under + + + align:start position:0% +The following content is provided under +a Creative Common License. Your support + + align:start position:0% +a Creative Common License. Your support + + + align:start position:0% +a Creative Common License. Your support +will help MIT Open Courseware continue + + align:start position:0% +will help MIT Open Courseware continue + + + align:start position:0% +will help MIT Open Courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free. To make a donation + + align:start position:0% +resources for free. To make a donation + + + align:start position:0% +resources for free. To make a donation +or to view additional materials from + + align:start position:0% +or to view additional materials from + + + align:start position:0% +or to view additional materials from +hundreds of MIT courses, visit MIT Open + + align:start position:0% +hundreds of MIT courses, visit MIT Open + + + align:start position:0% +hundreds of MIT courses, visit MIT Open +Courseware at ocw.mmit.edu. + + align:start position:0% + + + + align:start position:0% + +Hey guys. + + align:start position:0% +Hey guys. + + + align:start position:0% +Hey guys. +So these are our special guest lectures + + align:start position:0% +So these are our special guest lectures + + + align:start position:0% +So these are our special guest lectures +for + + align:start position:0% +for + + + align:start position:0% +for +today. These are sixth graders from the + + align:start position:0% +today. These are sixth graders from the + + + align:start position:0% +today. These are sixth graders from the +RT. You guys want to go ahead + + align:start position:0% + + + + align:start position:0% + +And everyone rotate. + + align:start position:0% + + + + align:start position:0% + +Hi. Music matters. It really does. Are + + align:start position:0% +Hi. Music matters. It really does. Are + + + align:start position:0% +Hi. Music matters. It really does. Are +you a musician? Yep. Where you play? I + + align:start position:0% +you a musician? Yep. Where you play? I + + + align:start position:0% +you a musician? Yep. Where you play? I +play the snare drum, the bass drum, tan, + + align:start position:0% +play the snare drum, the bass drum, tan, + + + align:start position:0% +play the snare drum, the bass drum, tan, +marine, pretty much all + + align:start position:0% +marine, pretty much all + + + align:start position:0% +marine, pretty much all +the guys trying. + + align:start position:0% +the guys trying. + + + align:start position:0% +the guys trying. +That's really cool. All + + align:start position:0% +That's really cool. All + + + align:start position:0% +That's really cool. All +right, you guys. So, before we get + + align:start position:0% +right, you guys. So, before we get + + + align:start position:0% +right, you guys. So, before we get +started, um the way this is going to + + align:start position:0% +started, um the way this is going to + + + align:start position:0% +started, um the way this is going to +work is give you um five minutes at each + + align:start position:0% +work is give you um five minutes at each + + + align:start position:0% +work is give you um five minutes at each +station with your consultants. Um and + + align:start position:0% +station with your consultants. Um and + + + align:start position:0% +station with your consultants. Um and +during this five minutes, go ahead and + + align:start position:0% +during this five minutes, go ahead and + + + align:start position:0% +during this five minutes, go ahead and +uh this is for the MIT students. Go + + align:start position:0% +uh this is for the MIT students. Go + + + align:start position:0% +uh this is for the MIT students. Go +ahead and introduce yourselves. Uh tell + + align:start position:0% +ahead and introduce yourselves. Uh tell + + + align:start position:0% +ahead and introduce yourselves. Uh tell +them what you study, maybe what year you + + align:start position:0% +them what you study, maybe what year you + + + align:start position:0% +them what you study, maybe what year you +are, what you're interested in. And then + + align:start position:0% +are, what you're interested in. And then + + + align:start position:0% +are, what you're interested in. And then +if you feel comfortable showing them the + + align:start position:0% +if you feel comfortable showing them the + + + align:start position:0% +if you feel comfortable showing them the +video pitch that you made last night, we + + align:start position:0% +video pitch that you made last night, we + + + align:start position:0% +video pitch that you made last night, we +we have this to deal with. So, just just + + align:start position:0% +we have this to deal with. So, just just + + + align:start position:0% +we have this to deal with. So, just just +know that that's out of our control and + + align:start position:0% +know that that's out of our control and + + + align:start position:0% +know that that's out of our control and +we're really sorry that they're doing + + align:start position:0% +we're really sorry that they're doing + + + align:start position:0% +we're really sorry that they're doing +some construction over there and it's + + align:start position:0% +some construction over there and it's + + + align:start position:0% +some construction over there and it's +going to be a little noisy. Sorry. + + align:start position:0% +going to be a little noisy. Sorry. + + + align:start position:0% +going to be a little noisy. Sorry. +So, go ahead and show them your pitch if + + align:start position:0% +So, go ahead and show them your pitch if + + + align:start position:0% +So, go ahead and show them your pitch if +you're comfortable with it. If not, you + + align:start position:0% +you're comfortable with it. If not, you + + + align:start position:0% +you're comfortable with it. If not, you +can just tell them your idea and then + + align:start position:0% +can just tell them your idea and then + + + align:start position:0% +can just tell them your idea and then +workshop some of the backup ideas that + + align:start position:0% +workshop some of the backup ideas that + + + align:start position:0% +workshop some of the backup ideas that +you thought about last night and the + + align:start position:0% +you thought about last night and the + + + align:start position:0% +you thought about last night and the +Cummings Middle School students know + + align:start position:0% +Cummings Middle School students know + + + align:start position:0% +Cummings Middle School students know +exactly what criteria you're looking + + align:start position:0% +exactly what criteria you're looking + + + align:start position:0% +exactly what criteria you're looking +for, right? So, you can use the rubrics + + align:start position:0% +for, right? So, you can use the rubrics + + + align:start position:0% +for, right? So, you can use the rubrics +that that we gave you. Um, and at the + + align:start position:0% +that that we gave you. Um, and at the + + + align:start position:0% +that that we gave you. Um, and at the +end of the five minutes, we're we're + + align:start position:0% +end of the five minutes, we're we're + + + align:start position:0% +end of the five minutes, we're we're +gonna have the MIT students rotate. So, + + align:start position:0% +gonna have the MIT students rotate. So, + + + align:start position:0% +gonna have the MIT students rotate. So, +um, Nathan, you'll go to the back. Paul, + + align:start position:0% +um, Nathan, you'll go to the back. Paul, + + + align:start position:0% +um, Nathan, you'll go to the back. Paul, +you'll scoot here. Everyone will just + + align:start position:0% +you'll scoot here. Everyone will just + + + align:start position:0% +you'll scoot here. Everyone will just +shift that way. Does that make sense to + + align:start position:0% +shift that way. Does that make sense to + + + align:start position:0% +shift that way. Does that make sense to +everyone? We'll try it out for the first + + align:start position:0% +everyone? We'll try it out for the first + + + align:start position:0% +everyone? We'll try it out for the first +time. Um, and if anyone has any + + align:start position:0% +time. Um, and if anyone has any + + + align:start position:0% +time. Um, and if anyone has any +questions, you can always come talk to + + align:start position:0% +questions, you can always come talk to + + + align:start position:0% +questions, you can always come talk to +one of the instructors. Okay. So, does + + align:start position:0% +one of the instructors. Okay. So, does + + + align:start position:0% +one of the instructors. Okay. So, does +anyone have any questions about how this + + align:start position:0% +anyone have any questions about how this + + + align:start position:0% +anyone have any questions about how this +is going to work before we get started + + align:start position:0% +is going to work before we get started + + + align:start position:0% +is going to work before we get started +or what your job is? Does anyone have a + + align:start position:0% +or what your job is? Does anyone have a + + + align:start position:0% +or what your job is? Does anyone have a +question about that either? + + align:start position:0% +question about that either? + + + align:start position:0% +question about that either? +Good job. Your job. It's a very + + align:start position:0% +Good job. Your job. It's a very + + + align:start position:0% +Good job. Your job. It's a very +important job. Your critics, + + align:start position:0% +important job. Your critics, + + + align:start position:0% +important job. Your critics, +right? All right, then. It looks like + + align:start position:0% +right? All right, then. It looks like + + + align:start position:0% +right? All right, then. It looks like +everyone knows what to do. So, I will go + + align:start position:0% +everyone knows what to do. So, I will go + + + align:start position:0% +everyone knows what to do. So, I will go +ahead and start the timer for the first + + align:start position:0% +ahead and start the timer for the first + + + align:start position:0% +ahead and start the timer for the first +five minutes. Um, and if at any point + + align:start position:0% +five minutes. Um, and if at any point + + + align:start position:0% +five minutes. Um, and if at any point +you have a question about what you're + + align:start position:0% +you have a question about what you're + + + align:start position:0% +you have a question about what you're +doing or just a clarification, then you + + align:start position:0% +doing or just a clarification, then you + + + align:start position:0% +doing or just a clarification, then you +can come find one of us. Yeah. + + align:start position:0% +can come find one of us. Yeah. + + + align:start position:0% +can come find one of us. Yeah. +Have fun. + + align:start position:0% +Have fun. + + + align:start position:0% +Have fun. +Right. Yeah. Just a short introduction. + + align:start position:0% +Right. Yeah. Just a short introduction. + + + align:start position:0% +Right. Yeah. Just a short introduction. +I study computer science. Anyone know + + align:start position:0% +I study computer science. Anyone know + + + align:start position:0% +I study computer science. Anyone know +what that is? Kind of like programming + + align:start position:0% +what that is? Kind of like programming + + + align:start position:0% +what that is? Kind of like programming +kind of stuff like Oh, and so the kind + + align:start position:0% +kind of stuff like Oh, and so the kind + + + align:start position:0% +kind of stuff like Oh, and so the kind +of stuff I like to do is like I make + + align:start position:0% +of stuff I like to do is like I make + + + align:start position:0% +of stuff I like to do is like I make +computer games. So this kind of like + + align:start position:0% +computer games. So this kind of like + + + align:start position:0% +computer games. So this kind of like +slash snowflake, you know? So you you + + align:start position:0% +slash snowflake, you know? So you you + + + align:start position:0% +slash snowflake, you know? So you you +it's kind of like Fruit Ninja. Ever + + align:start position:0% +it's kind of like Fruit Ninja. Ever + + + align:start position:0% +it's kind of like Fruit Ninja. Ever +heard of Fruit Ninja? But except cuz + + align:start position:0% +heard of Fruit Ninja? But except cuz + + + align:start position:0% +heard of Fruit Ninja? But except cuz +it's snowing today, you slash the + + align:start position:0% +it's snowing today, you slash the + + + align:start position:0% +it's snowing today, you slash the +snowflake. It's kind of like the same, + + align:start position:0% +snowflake. It's kind of like the same, + + + align:start position:0% +snowflake. It's kind of like the same, +but this time you get a lot of combos. + + align:start position:0% +but this time you get a lot of combos. + + + align:start position:0% +but this time you get a lot of combos. +Oh, if you slash the red one, you kind + + align:start position:0% +Oh, if you slash the red one, you kind + + + align:start position:0% +Oh, if you slash the red one, you kind +of lose time. You lose points and you + + align:start position:0% +of lose time. You lose points and you + + + align:start position:0% +of lose time. You lose points and you +eventually lose the game. It's kind of + + align:start position:0% +eventually lose the game. It's kind of + + + align:start position:0% +eventually lose the game. It's kind of +like the kind of things I do. Did you + + align:start position:0% +like the kind of things I do. Did you + + + align:start position:0% +like the kind of things I do. Did you +make that? Yeah, I made that. Oh, I + + align:start position:0% +make that? Yeah, I made that. Oh, I + + + align:start position:0% +make that? Yeah, I made that. Oh, I +didn't. Yeah, you can. You can. I got + + align:start position:0% +didn't. Yeah, you can. You can. I got + + + align:start position:0% +didn't. Yeah, you can. You can. I got +Fruit Ninja. It's kind of like Fruit + + align:start position:0% +Fruit Ninja. It's kind of like Fruit + + + align:start position:0% +Fruit Ninja. It's kind of like Fruit +Ninja, but except that don't slash the + + align:start position:0% +Ninja, but except that don't slash the + + + align:start position:0% +Ninja, but except that don't slash the +red snowflakes and it's okay if the + + align:start position:0% +red snowflakes and it's okay if the + + + align:start position:0% +red snowflakes and it's okay if the +snowflakes fall off. Oh, the blue ones + + align:start position:0% +snowflakes fall off. Oh, the blue ones + + + align:start position:0% +snowflakes fall off. Oh, the blue ones +give you these mega explosions and they + + align:start position:0% +give you these mega explosions and they + + + align:start position:0% +give you these mega explosions and they +can layer. Yeah. So, I have this idea + + align:start position:0% +can layer. Yeah. So, I have this idea + + + align:start position:0% +can layer. Yeah. So, I have this idea +like it's just without programming. How + + align:start position:0% +like it's just without programming. How + + + align:start position:0% +like it's just without programming. How +can you make computer games? That's kind + + align:start position:0% +can you make computer games? That's kind + + + align:start position:0% +can you make computer games? That's kind +of like what I was thinking of off my + + align:start position:0% +of like what I was thinking of off my + + + align:start position:0% +of like what I was thinking of off my +head. What do you think of that? Like um + + align:start position:0% +head. What do you think of that? Like um + + + align:start position:0% +head. What do you think of that? Like um +Do you have like things you like when + + align:start position:0% +Do you have like things you like when + + + align:start position:0% +Do you have like things you like when +you playing your phone? Do do you play + + align:start position:0% +you playing your phone? Do do you play + + + align:start position:0% +you playing your phone? Do do you play +games a lot on your phone? Yeah, + + align:start position:0% +games a lot on your phone? Yeah, + + + align:start position:0% +games a lot on your phone? Yeah, +definitely. Right. What's your favorite? + + align:start position:0% +definitely. Right. What's your favorite? + + + align:start position:0% +definitely. Right. What's your favorite? +Oh, + + align:start position:0% +Oh, + + + align:start position:0% +Oh, +um I like a lot of them. I love social + + align:start position:0% +um I like a lot of them. I love social + + + align:start position:0% +um I like a lot of them. I love social +media. Ah, social media. That kind of + + align:start position:0% +media. Ah, social media. That kind of + + + align:start position:0% +media. Ah, social media. That kind of +Yeah, that kind of thing. I don't really + + align:start position:0% +Yeah, that kind of thing. I don't really + + + align:start position:0% +Yeah, that kind of thing. I don't really +have a favorite. Oh, I see. I play + + align:start position:0% +have a favorite. Oh, I see. I play + + + align:start position:0% +have a favorite. Oh, I see. I play +Madden Mobile in Clash of Clans. Ah, + + align:start position:0% +Madden Mobile in Clash of Clans. Ah, + + + align:start position:0% +Madden Mobile in Clash of Clans. Ah, +Clash of Clans was thoroughly + + align:start position:0% +Clash of Clans was thoroughly + + + align:start position:0% +Clash of Clans was thoroughly +addictive. Yeah. So it'll probably be + + align:start position:0% +addictive. Yeah. So it'll probably be + + + align:start position:0% +addictive. Yeah. So it'll probably be +about like how can you come up ideas to + + align:start position:0% +about like how can you come up ideas to + + + align:start position:0% +about like how can you come up ideas to +make games because honestly the people + + align:start position:0% +make games because honestly the people + + + align:start position:0% +make games because honestly the people +who is trying to make games are probably + + align:start position:0% +who is trying to make games are probably + + + align:start position:0% +who is trying to make games are probably +not as smart as anyone out there cuz you + + align:start position:0% +not as smart as anyone out there cuz you + + + align:start position:0% +not as smart as anyone out there cuz you +play the games. You know what people + + align:start position:0% +play the games. You know what people + + + align:start position:0% +play the games. You know what people +like to play and it's not it's not me + + align:start position:0% +like to play and it's not it's not me + + + align:start position:0% +like to play and it's not it's not me +it's it's you you know what likes to + + align:start position:0% +it's it's you you know what likes to + + + align:start position:0% +it's it's you you know what likes to +play. So if people like you could make + + align:start position:0% +play. So if people like you could make + + + align:start position:0% +play. So if people like you could make +the games that people that of all ages + + align:start position:0% +the games that people that of all ages + + + align:start position:0% +the games that people that of all ages +could play then that would be great, + + align:start position:0% +could play then that would be great, + + + align:start position:0% +could play then that would be great, +right? Yeah. Okay. Well, just just + + align:start position:0% +right? Yeah. Okay. Well, just just + + + align:start position:0% +right? Yeah. Okay. Well, just just +another curious cat question. Do you + + align:start position:0% +another curious cat question. Do you + + + align:start position:0% +another curious cat question. Do you +know what a hacker is? + + align:start position:0% +know what a hacker is? + + + align:start position:0% +know what a hacker is? +What? No. Hacker. Oh, a hacker. Yeah, a + + align:start position:0% +What? No. Hacker. Oh, a hacker. Yeah, a + + + align:start position:0% +What? No. Hacker. Oh, a hacker. Yeah, a +hacker. Oh, yeah. Someone tries to like + + align:start position:0% +hacker. Oh, yeah. Someone tries to like + + + align:start position:0% +hacker. Oh, yeah. Someone tries to like +invade the + + align:start position:0% +invade the + + + align:start position:0% +invade the +firewall thingy or Uhhuh. security get + + align:start position:0% +firewall thingy or Uhhuh. security get + + + align:start position:0% +firewall thingy or Uhhuh. security get +through the security bar. Yeah. Yeah. + + align:start position:0% +through the security bar. Yeah. Yeah. + + + align:start position:0% +through the security bar. Yeah. Yeah. +Would you like would you want to know + + align:start position:0% +Would you like would you want to know + + + align:start position:0% +Would you like would you want to know +what + + align:start position:0% +what + + + align:start position:0% +what +what they do? No, I don't. No. Okay, + + align:start position:0% +what they do? No, I don't. No. Okay, + + + align:start position:0% +what they do? No, I don't. No. Okay, +then let's just script it. How about a + + align:start position:0% +then let's just script it. How about a + + + align:start position:0% +then let's just script it. How about a +curious question? Everyone knows Google, + + align:start position:0% +curious question? Everyone knows Google, + + + align:start position:0% +curious question? Everyone knows Google, +right? Yeah. But what do they do? + + align:start position:0% +right? Yeah. But what do they do? + + + align:start position:0% +right? Yeah. But what do they do? +search engine. Okay. Yeah. So, um and + + align:start position:0% +search engine. Okay. Yeah. So, um and + + + align:start position:0% +search engine. Okay. Yeah. So, um and +then what what does that what does that + + align:start position:0% +then what what does that what does that + + + align:start position:0% +then what what does that what does that +make them like? How are they like so + + align:start position:0% +make them like? How are they like so + + + align:start position:0% +make them like? How are they like so +important in our lives? Oh, cuz we like + + align:start position:0% +important in our lives? Oh, cuz we like + + + align:start position:0% +important in our lives? Oh, cuz we like +when we do our homework like kind of + + align:start position:0% +when we do our homework like kind of + + + align:start position:0% +when we do our homework like kind of +look up on Google that stuff. Okay. + + align:start position:0% +look up on Google that stuff. Okay. + + + align:start position:0% +look up on Google that stuff. Okay. +History is helpful. + + align:start position:0% +History is helpful. + + + align:start position:0% +History is helpful. +Yeah. Okay. You can also ask Siri on + + align:start position:0% +Yeah. Okay. You can also ask Siri on + + + align:start position:0% +Yeah. Okay. You can also ask Siri on +like your phone or something like a + + align:start position:0% +like your phone or something like a + + + align:start position:0% +like your phone or something like a +button. Okay. Just curious. Do you do + + align:start position:0% +button. Okay. Just curious. Do you do + + + align:start position:0% +button. Okay. Just curious. Do you do +you cuz I'm I'm actually not from US. + + align:start position:0% +you cuz I'm I'm actually not from US. + + + align:start position:0% +you cuz I'm I'm actually not from US. +I'm actually from a little country in + + align:start position:0% +I'm actually from a little country in + + + align:start position:0% +I'm actually from a little country in +Asia called Singapore. Yeah. So I'm just + + align:start position:0% +Asia called Singapore. Yeah. So I'm just + + + align:start position:0% +Asia called Singapore. Yeah. So I'm just +curious. Do you study programming at + + align:start position:0% +curious. Do you study programming at + + + align:start position:0% +curious. Do you study programming at +your age? No. Like any kind. So Okay. Me + + align:start position:0% +your age? No. Like any kind. So Okay. Me + + + align:start position:0% +your age? No. Like any kind. So Okay. Me +neither. I've never studied programming + + align:start position:0% +neither. I've never studied programming + + + align:start position:0% +neither. I've never studied programming +until I came to university. Yes. Yeah. + + align:start position:0% +until I came to university. Yes. Yeah. + + + align:start position:0% +until I came to university. Yes. Yeah. +So yeah. So what do you think program + + align:start position:0% +So yeah. So what do you think program + + + align:start position:0% +So yeah. So what do you think program +like? What do you think programmers do? + + align:start position:0% +like? What do you think programmers do? + + + align:start position:0% +like? What do you think programmers do? +Um, they create, they help build games + + align:start position:0% +Um, they create, they help build games + + + align:start position:0% +Um, they create, they help build games +and code and stuff. If you were to be + + align:start position:0% +and code and stuff. If you were to be + + + align:start position:0% +and code and stuff. If you were to be +like curious about what a programmer or + + align:start position:0% +like curious about what a programmer or + + + align:start position:0% +like curious about what a programmer or +or what can he do, what what would + + align:start position:0% +or what can he do, what what would + + + align:start position:0% +or what can he do, what what would +interest you games perhaps? Yeah. + + align:start position:0% +interest you games perhaps? Yeah. + + + align:start position:0% +interest you games perhaps? Yeah. +Anything else? + + align:start position:0% +Anything else? + + + align:start position:0% +Anything else? +I pretty much just play games. + + align:start position:0% +I pretty much just play games. + + + align:start position:0% +I pretty much just play games. +Yeah. I can't call online cuz it's an + + align:start position:0% +Yeah. I can't call online cuz it's an + + + align:start position:0% +Yeah. I can't call online cuz it's an +iPod. I don't have an iPhone. I only + + align:start position:0% +iPod. I don't have an iPhone. I only + + + align:start position:0% +iPod. I don't have an iPhone. I only +have an iPod. So, yeah. + + align:start position:0% + + + + align:start position:0% + +So, out of the like random ideas to um + + align:start position:0% +So, out of the like random ideas to um + + + align:start position:0% +So, out of the like random ideas to um +which one like would would you be + + align:start position:0% +which one like would would you be + + + align:start position:0% +which one like would would you be +interested in in like a possible video? + + align:start position:0% +interested in in like a possible video? + + + align:start position:0% +interested in in like a possible video? +Um football games like football games. + + align:start position:0% +Um football games like football games. + + + align:start position:0% +Um football games like football games. +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +Yeah. + + align:start position:0% +Yeah. + + + align:start position:0% +Yeah. +Um I don't know. + + align:start position:0% +Um I don't know. + + + align:start position:0% +Um I don't know. +I think + + align:start position:0% +I think + + + align:start position:0% +I think +something has to do with What's the like + + align:start position:0% +something has to do with What's the like + + + align:start position:0% +something has to do with What's the like +the weirdest thing you have in your + + align:start position:0% +the weirdest thing you have in your + + + align:start position:0% +the weirdest thing you have in your +mind? Like it always nags you about + + align:start position:0% +mind? Like it always nags you about + + + align:start position:0% +mind? Like it always nags you about +computers. I guess it's too slow + + align:start position:0% +computers. I guess it's too slow + + + align:start position:0% +computers. I guess it's too slow +sometimes. It's too slow. Yeah, too + + align:start position:0% +sometimes. It's too slow. Yeah, too + + + align:start position:0% +sometimes. It's too slow. Yeah, too +slow. Like even when you have Wi-Fi in + + align:start position:0% +slow. Like even when you have Wi-Fi in + + + align:start position:0% +slow. Like even when you have Wi-Fi in +range and you're like near the router or + + align:start position:0% +range and you're like near the router or + + + align:start position:0% +range and you're like near the router or +something, it's always really slow. Oh, + + align:start position:0% +something, it's always really slow. Oh, + + + align:start position:0% +something, it's always really slow. Oh, +okay. Oh, yeah. And Wi-Fi. You can't get + + align:start position:0% +okay. Oh, yeah. And Wi-Fi. You can't get + + + align:start position:0% +okay. Oh, yeah. And Wi-Fi. You can't get +like when I'm in my car, I can't play on + + align:start position:0% +like when I'm in my car, I can't play on + + + align:start position:0% +like when I'm in my car, I can't play on +like the internet and stuff. Ah, okay. I + + align:start position:0% +like the internet and stuff. Ah, okay. I + + + align:start position:0% +like the internet and stuff. Ah, okay. I +can play games that don't need internet. + + align:start position:0% +can play games that don't need internet. + + + align:start position:0% +can play games that don't need internet. +Yeah. Okay. So, like I don't like Wi-Fi + + align:start position:0% +Yeah. Okay. So, like I don't like Wi-Fi + + + align:start position:0% +Yeah. Okay. So, like I don't like Wi-Fi +cuz I would We should have builtin Wi-Fi + + align:start position:0% +cuz I would We should have builtin Wi-Fi + + + align:start position:0% +cuz I would We should have builtin Wi-Fi +and everything. So, that would be cool. + + align:start position:0% +and everything. So, that would be cool. + + + align:start position:0% +and everything. So, that would be cool. +Okay. What about um maybe um you know + + align:start position:0% +Okay. What about um maybe um you know + + + align:start position:0% +Okay. What about um maybe um you know +Pixar? You like the movies? Yeah. Oh, I + + align:start position:0% +Pixar? You like the movies? Yeah. Oh, I + + + align:start position:0% +Pixar? You like the movies? Yeah. Oh, I +I love The Incredibles, but that was + + align:start position:0% +I love The Incredibles, but that was + + + align:start position:0% +I love The Incredibles, but that was +really old, but I still love it here + + align:start position:0% +really old, but I still love it here + + + align:start position:0% +really old, but I still love it here +today. Like Yeah. And have you ever + + align:start position:0% +today. Like Yeah. And have you ever + + + align:start position:0% +today. Like Yeah. And have you ever +wondered like how they do it? It kind of + + align:start position:0% +wondered like how they do it? It kind of + + + align:start position:0% +wondered like how they do it? It kind of +looks different from like the normal + + align:start position:0% +looks different from like the normal + + + align:start position:0% +looks different from like the normal +Yeah. So, they actually use some + + align:start position:0% +Yeah. So, they actually use some + + + align:start position:0% +Yeah. So, they actually use some +computer software to do it. It's called + + align:start position:0% +computer software to do it. It's called + + + align:start position:0% +computer software to do it. It's called +3D animation like threedimensional. Is + + align:start position:0% +3D animation like threedimensional. Is + + + align:start position:0% +3D animation like threedimensional. Is +that like interesting or Yeah, I would + + align:start position:0% +that like interesting or Yeah, I would + + + align:start position:0% +that like interesting or Yeah, I would +be interested in that. Yeah. Like how do + + align:start position:0% +be interested in that. Yeah. Like how do + + + align:start position:0% +be interested in that. Yeah. Like how do +you draw but on the computer? Like do + + align:start position:0% +you draw but on the computer? Like do + + + align:start position:0% +you draw but on the computer? Like do +they have to draw all little pictures + + align:start position:0% +they have to draw all little pictures + + + align:start position:0% +they have to draw all little pictures +like of every movement like ah that's + + align:start position:0% +like of every movement like ah that's + + + align:start position:0% +like of every movement like ah that's +the key. It's no. It's actually the + + align:start position:0% +the key. It's no. It's actually the + + + align:start position:0% +the key. It's no. It's actually the +answer is no. Oh yeah they did. It's + + align:start position:0% +answer is no. Oh yeah they did. It's + + + align:start position:0% +answer is no. Oh yeah they did. It's +pretty cool right? What they do is like + + align:start position:0% +pretty cool right? What they do is like + + + align:start position:0% +pretty cool right? What they do is like +kind of like they make a teddy bear in + + align:start position:0% +kind of like they make a teddy bear in + + + align:start position:0% +kind of like they make a teddy bear in +in the computer like some kind of like + + align:start position:0% +in the computer like some kind of like + + + align:start position:0% +in the computer like some kind of like +3D image of it and they put bones in + + align:start position:0% +3D image of it and they put bones in + + + align:start position:0% +3D image of it and they put bones in +like like just like how you put bones in + + align:start position:0% +like like just like how you put bones in + + + align:start position:0% +like like just like how you put bones in +humans but you programming you put like + + align:start position:0% +humans but you programming you put like + + + align:start position:0% +humans but you programming you put like +logical bones and then you can shift the + + align:start position:0% +logical bones and then you can shift the + + + align:start position:0% +logical bones and then you can shift the +bones and you're like puppets you know. + + align:start position:0% +bones and you're like puppets you know. + + + align:start position:0% +bones and you're like puppets you know. +Yeah. Yeah. That's kind of like what + + align:start position:0% +Yeah. Yeah. That's kind of like what + + + align:start position:0% +Yeah. Yeah. That's kind of like what +they're doing all the time. + + align:start position:0% +they're doing all the time. + + + align:start position:0% +they're doing all the time. +Okay. So which one of the ideas was like + + align:start position:0% +Okay. So which one of the ideas was like + + + align:start position:0% +Okay. So which one of the ideas was like +I like the last one. Last one. Yeah. The + + align:start position:0% +I like the last one. Last one. Yeah. The + + + align:start position:0% +I like the last one. Last one. Yeah. The +last one the most. All right. Thank you + + align:start position:0% +last one the most. All right. Thank you + + + align:start position:0% +last one the most. All right. Thank you +guys. You're so amazing. + + align:start position:0% +guys. You're so amazing. + + + align:start position:0% +guys. You're so amazing. +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +I'm Michael. I'm going to sit down with + + align:start position:0% +I'm Michael. I'm going to sit down with + + + align:start position:0% +I'm Michael. I'm going to sit down with +you guys, too. My name is Sarah. + + align:start position:0% +you guys, too. My name is Sarah. + + + align:start position:0% +you guys, too. My name is Sarah. +Um I'm + + align:start position:0% +Um I'm + + + align:start position:0% +Um I'm +Nathan. Um I + + align:start position:0% +Nathan. Um I + + + align:start position:0% +Nathan. Um I +study something that's a mix of + + align:start position:0% +study something that's a mix of + + + align:start position:0% +study something that's a mix of +mechanical today and geology. + + align:start position:0% +mechanical today and geology. + + + align:start position:0% +mechanical today and geology. +Geology. Mhm. + + align:start position:0% +Geology. Mhm. + + + align:start position:0% +Geology. Mhm. +Um sorry. Yeah. I'm a second year. + + align:start position:0% +Um sorry. Yeah. I'm a second year. + + + align:start position:0% +Um sorry. Yeah. I'm a second year. +I have two ideas. It looks like my main + + align:start position:0% +I have two ideas. It looks like my main + + + align:start position:0% +I have two ideas. It looks like my main +idea has been scrapped at this point. + + align:start position:0% +idea has been scrapped at this point. + + + align:start position:0% +idea has been scrapped at this point. +Um, but I'll still mention it to you in + + align:start position:0% +Um, but I'll still mention it to you in + + + align:start position:0% +Um, but I'll still mention it to you in +case one of you is fervently interested + + align:start position:0% +case one of you is fervently interested + + + align:start position:0% +case one of you is fervently interested +in it, which is I was interested in + + align:start position:0% +in it, which is I was interested in + + + align:start position:0% +in it, which is I was interested in +possibly doing something on how and why + + align:start position:0% +possibly doing something on how and why + + + align:start position:0% +possibly doing something on how and why +food + + align:start position:0% +food + + + align:start position:0% +food +decomposes. Um, but I guess my backup + + align:start position:0% +decomposes. Um, but I guess my backup + + + align:start position:0% +decomposes. Um, but I guess my backup +idea was is a bit more interesting to + + align:start position:0% +idea was is a bit more interesting to + + + align:start position:0% +idea was is a bit more interesting to +most people. Uh, which + + align:start position:0% +most people. Uh, which + + + align:start position:0% +most people. Uh, which +is how you can tell if there's like + + align:start position:0% +is how you can tell if there's like + + + align:start position:0% +is how you can tell if there's like +magma or lava under a surface like and + + align:start position:0% +magma or lava under a surface like and + + + align:start position:0% +magma or lava under a surface like and +how you can detect and map it and then + + align:start position:0% +how you can detect and map it and then + + + align:start position:0% +how you can detect and map it and then +you might be able to say, "Oh, is this + + align:start position:0% +you might be able to say, "Oh, is this + + + align:start position:0% +you might be able to say, "Oh, is this +place in risk of having some sort of + + align:start position:0% +place in risk of having some sort of + + + align:start position:0% +place in risk of having some sort of +eruption at some point + + align:start position:0% +eruption at some point + + + align:start position:0% +eruption at some point +um or not?" Still have to work on the + + align:start position:0% +um or not?" Still have to work on the + + + align:start position:0% +um or not?" Still have to work on the +hook. + + align:start position:0% +hook. + + + align:start position:0% +hook. +Um I don't + + align:start position:0% +Um I don't + + + align:start position:0% +Um I don't +know. I'm + + align:start position:0% +know. I'm + + + align:start position:0% +know. I'm +here do you think is more interesting? + + align:start position:0% +here do you think is more interesting? + + + align:start position:0% +here do you think is more interesting? +What was the first one? Uh um how and + + align:start position:0% +What was the first one? Uh um how and + + + align:start position:0% +What was the first one? Uh um how and +why food rots and decomposes. + + align:start position:0% +why food rots and decomposes. + + + align:start position:0% +why food rots and decomposes. +Yeah. + + align:start position:0% +Yeah. + + + align:start position:0% +Yeah. +I would probably do the lava stuff. + + align:start position:0% +I would probably do the lava stuff. + + + align:start position:0% +I would probably do the lava stuff. +Yeah, it's like + + align:start position:0% +Yeah, it's like + + + align:start position:0% +Yeah, it's like +Yeah, save lives. + + align:start position:0% +Yeah, save lives. + + + align:start position:0% +Yeah, save lives. +Yeah. Um, so I know + + align:start position:0% +Yeah. Um, so I know + + + align:start position:0% +Yeah. Um, so I know +exactly what to say about that. Um, + + align:start position:0% +exactly what to say about that. Um, + + + align:start position:0% +exactly what to say about that. Um, +what would you be like expecting if you + + align:start position:0% +what would you be like expecting if you + + + align:start position:0% +what would you be like expecting if you +wanted to watch a video about lava? Like + + align:start position:0% +wanted to watch a video about lava? Like + + + align:start position:0% +wanted to watch a video about lava? Like +what would you want to be? + + align:start position:0% +what would you want to be? + + + align:start position:0% +what would you want to be? +A diagram of the Earth. Okay. probably + + align:start position:0% +A diagram of the Earth. Okay. probably + + + align:start position:0% +A diagram of the Earth. Okay. probably +having the lithosphere and a cenosphere + + align:start position:0% +having the lithosphere and a cenosphere + + + align:start position:0% +having the lithosphere and a cenosphere +and like the layers and then having like + + align:start position:0% +and like the layers and then having like + + + align:start position:0% +and like the layers and then having like +problems like you said how you can + + align:start position:0% +problems like you said how you can + + + align:start position:0% +problems like you said how you can +detect if there's lava under a surface + + align:start position:0% +detect if there's lava under a surface + + + align:start position:0% +detect if there's lava under a surface +probably having like a place that + + align:start position:0% +probably having like a place that + + + align:start position:0% +probably having like a place that +already does have lava under the surface + + align:start position:0% +already does have lava under the surface + + + align:start position:0% +already does have lava under the surface +and like showing the magma chamber + + align:start position:0% +and like showing the magma chamber + + + align:start position:0% +and like showing the magma chamber +stuff. + + align:start position:0% + + + + align:start position:0% + +Do you have It sounds like you guys have + + align:start position:0% +Do you have It sounds like you guys have + + + align:start position:0% +Do you have It sounds like you guys have +already done a unit on volcanoes like + + align:start position:0% +already done a unit on volcanoes like + + + align:start position:0% +already done a unit on volcanoes like +um is there any like any questions that + + align:start position:0% +um is there any like any questions that + + + align:start position:0% +um is there any like any questions that +you still have after that that you might + + align:start position:0% +you still have after that that you might + + + align:start position:0% +you still have after that that you might +want to have answered like really + + align:start position:0% +want to have answered like really + + + align:start position:0% +want to have answered like really +volcanoes or things like + + align:start position:0% +volcanoes or things like + + + align:start position:0% +volcanoes or things like +that? I know it's kind of a hard + + align:start position:0% +that? I know it's kind of a hard + + + align:start position:0% +that? I know it's kind of a hard +question + + align:start position:0% + + + + align:start position:0% + +or like the coolest part of the unit + + align:start position:0% +or like the coolest part of the unit + + + align:start position:0% +or like the coolest part of the unit +that you + + align:start position:0% +that you + + + align:start position:0% +that you +remember how it looks. I've seen videos + + align:start position:0% +remember how it looks. I've seen videos + + + align:start position:0% +remember how it looks. I've seen videos +of volcanoes erupting at night. + + align:start position:0% + + + + align:start position:0% + +I'd probably probably question I + + align:start position:0% +I'd probably probably question I + + + align:start position:0% +I'd probably probably question I +have there's some volcanoes that do like + + align:start position:0% +have there's some volcanoes that do like + + + align:start position:0% +have there's some volcanoes that do like +they're big but they have small + + align:start position:0% +they're big but they have small + + + align:start position:0% +they're big but they have small +eruptions and then they do like a big + + align:start position:0% +eruptions and then they do like a big + + + align:start position:0% +eruptions and then they do like a big +one and then there's other volcanoes + + align:start position:0% +one and then there's other volcanoes + + + align:start position:0% +one and then there's other volcanoes +that just like have huge eruptions every + + align:start position:0% +that just like have huge eruptions every + + + align:start position:0% +that just like have huge eruptions every +time they go. + + align:start position:0% +time they go. + + + align:start position:0% +time they go. +Why would some volcanoes have big + + align:start position:0% +Why would some volcanoes have big + + + align:start position:0% +Why would some volcanoes have big +eruptions and some have small small and + + align:start position:0% +eruptions and some have small small and + + + align:start position:0% +eruptions and some have small small and +then a big eruption? All right, + + align:start position:0% + + + + align:start position:0% + +so here's what I would say. Um, of + + align:start position:0% +so here's what I would say. Um, of + + + align:start position:0% +so here's what I would say. Um, of +volcanoes that tend to have small + + align:start position:0% +volcanoes that tend to have small + + + align:start position:0% +volcanoes that tend to have small +eruptions. It's actually based a lot on + + align:start position:0% +eruptions. It's actually based a lot on + + + align:start position:0% +eruptions. It's actually based a lot on +what the makeup of the reef the lava + + align:start position:0% +what the makeup of the reef the lava + + + align:start position:0% +what the makeup of the reef the lava +from the volcano is. + + align:start position:0% +from the volcano is. + + + align:start position:0% +from the volcano is. +Um I don't know if you did you cover um + + align:start position:0% +Um I don't know if you did you cover um + + + align:start position:0% +Um I don't know if you did you cover um +the difference between andic + + align:start position:0% +the difference between andic + + + align:start position:0% +the difference between andic +um and amocidic um + + align:start position:0% +um and amocidic um + + + align:start position:0% +um and amocidic um +volcanoes um basically + + align:start position:0% +volcanoes um basically + + + align:start position:0% +volcanoes um basically +um glass is made of something called sil + + align:start position:0% +um glass is made of something called sil + + + align:start position:0% +um glass is made of something called sil +um silicon silicate + + align:start position:0% +um silicon silicate + + + align:start position:0% +um silicon silicate +uh um it's an element and volcanoes that + + align:start position:0% +uh um it's an element and volcanoes that + + + align:start position:0% +uh um it's an element and volcanoes that +have a lot more silica in it um they + + align:start position:0% +have a lot more silica in it um they + + + align:start position:0% +have a lot more silica in it um they +tend to be a little less dense and once + + align:start position:0% +tend to be a little less dense and once + + + align:start position:0% +tend to be a little less dense and once +ones that have lower content are a lot + + align:start position:0% +ones that have lower content are a lot + + + align:start position:0% +ones that have lower content are a lot +heavier than magma. And so, as you might + + align:start position:0% +heavier than magma. And so, as you might + + + align:start position:0% +heavier than magma. And so, as you might +expect, the ones that are heavier when + + align:start position:0% +expect, the ones that are heavier when + + + align:start position:0% +expect, the ones that are heavier when +they erupt, it doesn't just shoot out + + align:start position:0% +they erupt, it doesn't just shoot out + + + align:start position:0% +they erupt, it doesn't just shoot out +everywhere. It just kind of like bubbles + + align:start position:0% +everywhere. It just kind of like bubbles + + + align:start position:0% +everywhere. It just kind of like bubbles +over the side and it's like more viscous + + align:start position:0% +over the side and it's like more viscous + + + align:start position:0% +over the side and it's like more viscous +and it flows slowly. And so those ones + + align:start position:0% +and it flows slowly. And so those ones + + + align:start position:0% +and it flows slowly. And so those ones +often will be the ones like the big + + align:start position:0% +often will be the ones like the big + + + align:start position:0% +often will be the ones like the big +mountains that + + align:start position:0% +mountains that + + + align:start position:0% +mountains that +like kind of like spread out this way a + + align:start position:0% +like kind of like spread out this way a + + + align:start position:0% +like kind of like spread out this way a +lot. Sort of like a shield volcano. + + align:start position:0% +lot. Sort of like a shield volcano. + + + align:start position:0% +lot. Sort of like a shield volcano. +Yeah, those are the shield volcanoes. + + align:start position:0% +Yeah, those are the shield volcanoes. + + + align:start position:0% +Yeah, those are the shield volcanoes. +And so the lava type causes it to have a + + align:start position:0% +And so the lava type causes it to have a + + + align:start position:0% +And so the lava type causes it to have a +lot more smaller eruptions because it + + align:start position:0% +lot more smaller eruptions because it + + + align:start position:0% +lot more smaller eruptions because it +takes a lot of buildup of pressure if + + align:start position:0% +takes a lot of buildup of pressure if + + + align:start position:0% +takes a lot of buildup of pressure if +you want to have a big eruption than + + align:start position:0% +you want to have a big eruption than + + + align:start position:0% +you want to have a big eruption than +that. Whereas when you have a higher + + align:start position:0% +that. Whereas when you have a higher + + + align:start position:0% +that. Whereas when you have a higher +silica content, which means it weighs + + align:start position:0% +silica content, which means it weighs + + + align:start position:0% +silica content, which means it weighs +less, it's going to explode more and + + align:start position:0% +less, it's going to explode more and + + + align:start position:0% +less, it's going to explode more and +it's going to have more violent + + align:start position:0% +it's going to have more violent + + + align:start position:0% +it's going to have more violent +eruptions. Um, and there's other factors + + align:start position:0% +eruptions. Um, and there's other factors + + + align:start position:0% +eruptions. Um, and there's other factors +as well, um, like water content, + + align:start position:0% +as well, um, like water content, + + + align:start position:0% +as well, um, like water content, +um, and at what depth the magma chamber + + align:start position:0% +um, and at what depth the magma chamber + + + align:start position:0% +um, and at what depth the magma chamber +underneath the volcano is. + + align:start position:0% + + + + align:start position:0% + +Yeah. Um, another question. Let me see. + + align:start position:0% +Yeah. Um, another question. Let me see. + + + align:start position:0% +Yeah. Um, another question. Let me see. +If you don't have one, I have one. All + + align:start position:0% +If you don't have one, I have one. All + + + align:start position:0% +If you don't have one, I have one. All +right. You um + + align:start position:0% + + + + align:start position:0% + +the Which was a long time and then blew + + align:start position:0% +the Which was a long time and then blew + + + align:start position:0% +the Which was a long time and then blew +his + + align:start position:0% +his + + + align:start position:0% +his +crazy. Yes. + + align:start position:0% +crazy. Yes. + + + align:start position:0% +crazy. Yes. +That's + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +what if volcanoes are doormat for a + + align:start position:0% +what if volcanoes are doormat for a + + + align:start position:0% +what if volcanoes are doormat for a +longer period when they erupt would they + + align:start position:0% +longer period when they erupt would they + + + align:start position:0% +longer period when they erupt would they +have a violent eruption than ones that a + + align:start position:0% +have a violent eruption than ones that a + + + align:start position:0% +have a violent eruption than ones that a +doormat shorter? Um I can't actually + + align:start position:0% +doormat shorter? Um I can't actually + + + align:start position:0% +doormat shorter? Um I can't actually +answer that question. Um, + + align:start position:0% +answer that question. Um, + + + align:start position:0% +answer that question. Um, +I know like what causes our parents to + + align:start position:0% +I know like what causes our parents to + + + align:start position:0% +I know like what causes our parents to +go in more dormant what make them might + + align:start position:0% +go in more dormant what make them might + + + align:start position:0% +go in more dormant what make them might +make them not dormant, but I can't + + align:start position:0% +make them not dormant, but I can't + + + align:start position:0% +make them not dormant, but I can't +really say if that would affect it. + + align:start position:0% +really say if that would affect it. + + + align:start position:0% +really say if that would affect it. +Okay. One thing about Matt that you have + + align:start position:0% +Okay. One thing about Matt that you have + + + align:start position:0% +Okay. One thing about Matt that you have +really enjoyed or really hated or two + + align:start position:0% +really enjoyed or really hated or two + + + align:start position:0% +really enjoyed or really hated or two +things. So, we'll start from left to + + align:start position:0% +things. So, we'll start from left to + + + align:start position:0% +things. So, we'll start from left to +right. + + align:start position:0% +right. + + + align:start position:0% +right. +So, name um favorite subject and things + + align:start position:0% +So, name um favorite subject and things + + + align:start position:0% +So, name um favorite subject and things +about math that you have really loved or + + align:start position:0% +about math that you have really loved or + + + align:start position:0% +about math that you have really loved or +really hated. Okay, my name is + + align:start position:0% +really hated. Okay, my name is + + + align:start position:0% +really hated. Okay, my name is +Brian. My favorite subject is gym and I + + align:start position:0% +Brian. My favorite subject is gym and I + + + align:start position:0% +Brian. My favorite subject is gym and I +hate + + align:start position:0% +hate + + + align:start position:0% +hate +math. Kind of + + align:start position:0% +math. Kind of + + + align:start position:0% +math. Kind of +boring. Okay. Um, actually there is I + + align:start position:0% +boring. Okay. Um, actually there is I + + + align:start position:0% +boring. Okay. Um, actually there is I +guess it's a kind of new direction, but + + align:start position:0% +guess it's a kind of new direction, but + + + align:start position:0% +guess it's a kind of new direction, but +a lot of people are actually studying + + align:start position:0% +a lot of people are actually studying + + + align:start position:0% +a lot of people are actually studying +the math of sports. So they go out and + + align:start position:0% +the math of sports. So they go out and + + + align:start position:0% +the math of sports. So they go out and +do really weird things with sports like + + align:start position:0% +do really weird things with sports like + + + align:start position:0% +do really weird things with sports like +throwing basketballs at + + align:start position:0% +throwing basketballs at + + + align:start position:0% +throwing basketballs at +like places where you should shoot an + + align:start position:0% +like places where you should shoot an + + + align:start position:0% +like places where you should shoot an +arrow kind of thing and they do math + + align:start position:0% +arrow kind of thing and they do math + + + align:start position:0% +arrow kind of thing and they do math +with it. So that's kind of a connection + + align:start position:0% +with it. So that's kind of a connection + + + align:start position:0% +with it. So that's kind of a connection +gym and + + align:start position:0% +gym and + + + align:start position:0% +gym and +math getting closer together. + + align:start position:0% +math getting closer together. + + + align:start position:0% +math getting closer together. +My name is Matt. I like math. + + align:start position:0% + + + + align:start position:0% + +You hear that, + + align:start position:0% +You hear that, + + + align:start position:0% +You hear that, +Brian? And what was the third thing that + + align:start position:0% +Brian? And what was the third thing that + + + align:start position:0% +Brian? And what was the third thing that +I have to say? Um, some things that you + + align:start position:0% +I have to say? Um, some things that you + + + align:start position:0% +I have to say? Um, some things that you +really enjoyed or hated about math. Um, + + align:start position:0% +really enjoyed or hated about math. Um, + + + align:start position:0% +really enjoyed or hated about math. Um, +I enjoy solving variables and equations + + align:start position:0% +I enjoy solving variables and equations + + + align:start position:0% +I enjoy solving variables and equations +and graphing things. + + align:start position:0% +and graphing things. + + + align:start position:0% +and graphing things. +That's good. You're ready for high + + align:start position:0% +That's good. You're ready for high + + + align:start position:0% +That's good. You're ready for high +school. burn. My name + + align:start position:0% +school. burn. My name + + + align:start position:0% +school. burn. My name +is My name is John and um my favorite + + align:start position:0% +is My name is John and um my favorite + + + align:start position:0% +is My name is John and um my favorite +subject is + + align:start position:0% +subject is + + + align:start position:0% +subject is +history and + + align:start position:0% +history and + + + align:start position:0% +history and +uh I personally do not like + + align:start position:0% +uh I personally do not like + + + align:start position:0% +uh I personally do not like +math. Um hi guys. + + align:start position:0% +math. Um hi guys. + + + align:start position:0% +math. Um hi guys. +Um, if I had to like say what I like + + align:start position:0% +Um, if I had to like say what I like + + + align:start position:0% +Um, if I had to like say what I like +about it, it would be + + align:start position:0% +about it, it would be + + + align:start position:0% +about it, it would be +like I'm really into like fractions kind + + align:start position:0% +like I'm really into like fractions kind + + + align:start position:0% +like I'm really into like fractions kind +of. Okay. I just like the idea. + + align:start position:0% +of. Okay. I just like the idea. + + + align:start position:0% +of. Okay. I just like the idea. +Okay. What do you know what about the + + align:start position:0% +Okay. What do you know what about the + + + align:start position:0% +Okay. What do you know what about the +idea? I've never heard anybody say I + + align:start position:0% +idea? I've never heard anybody say I + + + align:start position:0% +idea? I've never heard anybody say I +like the idea of fractions. So that's + + align:start position:0% +like the idea of fractions. So that's + + + align:start position:0% +like the idea of fractions. So that's +really interesting to me. + + align:start position:0% +really interesting to me. + + + align:start position:0% +really interesting to me. +think of like this table being like + + align:start position:0% +think of like this table being like + + + align:start position:0% +think of like this table being like +broken up into like a thousand. + + align:start position:0% + + + + align:start position:0% + +Now really wacky things that + + align:start position:0% +Now really wacky things that + + + align:start position:0% +Now really wacky things that +mathematicians do later on is that they + + align:start position:0% +mathematicians do later on is that they + + + align:start position:0% +mathematicians do later on is that they +don't just break the table into a + + align:start position:0% +don't just break the table into a + + + align:start position:0% +don't just break the table into a +thousand pieces. That's like too easy. + + align:start position:0% +thousand pieces. That's like too easy. + + + align:start position:0% +thousand pieces. That's like too easy. +They break it into an infinite number of + + align:start position:0% +They break it into an infinite number of + + + align:start position:0% +They break it into an infinite number of +pieces and then they see what they can + + align:start position:0% +pieces and then they see what they can + + + align:start position:0% +pieces and then they see what they can +do with that. + + align:start position:0% +do with that. + + + align:start position:0% +do with that. +Um and kind of related to that um math + + align:start position:0% +Um and kind of related to that um math + + + align:start position:0% +Um and kind of related to that um math +mathematicians have proved that you can + + align:start position:0% +mathematicians have proved that you can + + + align:start position:0% +mathematicians have proved that you can +take a ball of you know just volume one + + align:start position:0% +take a ball of you know just volume one + + + align:start position:0% +take a ball of you know just volume one +one gallon ball and you can cut it in + + align:start position:0% +one gallon ball and you can cut it in + + + align:start position:0% +one gallon ball and you can cut it in +such a way that you can make two onegon + + align:start position:0% +such a way that you can make two onegon + + + align:start position:0% +such a way that you can make two onegon +balls. So you can make two out of one + + align:start position:0% +balls. So you can make two out of one + + + align:start position:0% +balls. So you can make two out of one +using math. Um it's cool. So that's uh + + align:start position:0% +using math. Um it's cool. So that's uh + + + align:start position:0% +using math. Um it's cool. So that's uh +semi relative. You like math now boys? I + + align:start position:0% +semi relative. You like math now boys? I + + + align:start position:0% +semi relative. You like math now boys? I +still don't know. + + align:start position:0% +still don't know. + + + align:start position:0% +still don't know. +I mean, if you think about it, math + + align:start position:0% +I mean, if you think about it, math + + + align:start position:0% +I mean, if you think about it, math +people do really cool things. Like, um, + + align:start position:0% +people do really cool things. Like, um, + + + align:start position:0% +people do really cool things. Like, um, +there was a study once where they + + align:start position:0% +there was a study once where they + + + align:start position:0% +there was a study once where they +analyzed the language of King George and + + align:start position:0% +analyzed the language of King George and + + + align:start position:0% +analyzed the language of King George and +Kanye West and they compared them. And + + align:start position:0% +Kanye West and they compared them. And + + + align:start position:0% +Kanye West and they compared them. And +this is like an actual study, like they + + align:start position:0% +this is like an actual study, like they + + + align:start position:0% +this is like an actual study, like they +put time into it. So, I thought that was + + align:start position:0% +put time into it. So, I thought that was + + + align:start position:0% +put time into it. So, I thought that was +pretty cool. But, um, + + align:start position:0% +pretty cool. But, um, + + + align:start position:0% +pretty cool. But, um, +anyway, that's not what my pitch is + + align:start position:0% +anyway, that's not what my pitch is + + + align:start position:0% +anyway, that's not what my pitch is +about. Um, and I'll just kind of say + + align:start position:0% +about. Um, and I'll just kind of say + + + align:start position:0% +about. Um, and I'll just kind of say +real quick, not going to show the video + + align:start position:0% +real quick, not going to show the video + + + align:start position:0% +real quick, not going to show the video +because the sound is terrible. + + align:start position:0% +because the sound is terrible. + + + align:start position:0% +because the sound is terrible. +Um what I want to talk about in my video + + align:start position:0% +Um what I want to talk about in my video + + + align:start position:0% +Um what I want to talk about in my video +is just the question of is math real and + + align:start position:0% +is just the question of is math real and + + + align:start position:0% +is just the question of is math real and +true because what uh mathematicians + + align:start position:0% +true because what uh mathematicians + + + align:start position:0% +true because what uh mathematicians +learned in the 20th century um there was + + align:start position:0% +learned in the 20th century um there was + + + align:start position:0% +learned in the 20th century um there was +a young man named Kurt Girdle who proved + + align:start position:0% +a young man named Kurt Girdle who proved + + + align:start position:0% +a young man named Kurt Girdle who proved +that you can never prove if math is true + + align:start position:0% +that you can never prove if math is true + + + align:start position:0% +that you can never prove if math is true +or not. So the arithmetic we learned in + + align:start position:0% +or not. So the arithmetic we learned in + + + align:start position:0% +or not. So the arithmetic we learned in +school like we think it's true because + + align:start position:0% +school like we think it's true because + + + align:start position:0% +school like we think it's true because +it's worked but it may not be. There's + + align:start position:0% +it's worked but it may not be. There's + + + align:start position:0% +it's worked but it may not be. There's +no way to say for sure. Wait, is Kurt + + align:start position:0% +no way to say for sure. Wait, is Kurt + + + align:start position:0% +no way to say for sure. Wait, is Kurt +Kernel the guy who made Kentucky Fried + + align:start position:0% +Kernel the guy who made Kentucky Fried + + + align:start position:0% +Kernel the guy who made Kentucky Fried +Chicken? No, it's Kurt Girdle. + + align:start position:0% +Chicken? No, it's Kurt Girdle. + + + align:start position:0% +Chicken? No, it's Kurt Girdle. +Oh, I mean, I think it would be really + + align:start position:0% +Oh, I mean, I think it would be really + + + align:start position:0% +Oh, I mean, I think it would be really +cool if he did math and Kentucky Fried + + align:start position:0% +cool if he did math and Kentucky Fried + + + align:start position:0% +cool if he did math and Kentucky Fried +Chicken. Like, that would be the best. + + align:start position:0% +Chicken. Like, that would be the best. + + + align:start position:0% +Chicken. Like, that would be the best. +Our family guy. And he was like, he went + + align:start position:0% +Our family guy. And he was like, he went + + + align:start position:0% +Our family guy. And he was like, he went +to Kentucky to get chicken. He's like, + + align:start position:0% +to Kentucky to get chicken. He's like, + + + align:start position:0% +to Kentucky to get chicken. He's like, +is like whatever his name is sounding + + align:start position:0% +is like whatever his name is sounding + + + align:start position:0% +is like whatever his name is sounding +like what he said. And he's like, and + + align:start position:0% +like what he said. And he's like, and + + + align:start position:0% +like what he said. And he's like, and +he's like, no, he's dead. And he's like + + align:start position:0% +he's like, no, he's dead. And he's like + + + align:start position:0% +he's like, no, he's dead. And he's like +the something. That was so fun. Have to + + align:start position:0% +the something. That was so fun. Have to + + + align:start position:0% +the something. That was so fun. Have to +look into, you know, did any + + align:start position:0% +look into, you know, did any + + + align:start position:0% +look into, you know, did any +mathematicians open fast food chains? + + align:start position:0% +mathematicians open fast food chains? + + + align:start position:0% +mathematicians open fast food chains? +It's probably an interesting question. I + + align:start position:0% +It's probably an interesting question. I + + + align:start position:0% +It's probably an interesting question. I +don't think anyone's asked it before, + + align:start position:0% +don't think anyone's asked it before, + + + align:start position:0% +don't think anyone's asked it before, +but um that said, um any thoughts on the + + align:start position:0% +but um that said, um any thoughts on the + + + align:start position:0% +but um that said, um any thoughts on the +idea? Just I'll get a thumbs up, thumbs + + align:start position:0% +idea? Just I'll get a thumbs up, thumbs + + + align:start position:0% +idea? Just I'll get a thumbs up, thumbs +down, or thumbs middle. + + align:start position:0% +down, or thumbs middle. + + + align:start position:0% +down, or thumbs middle. +Okay. + + align:start position:0% + + + + align:start position:0% + +All right. Thanks, guys. Uh it was nice + + align:start position:0% +All right. Thanks, guys. Uh it was nice + + + align:start position:0% +All right. Thanks, guys. Uh it was nice +meeting you and enjoy playing or not. + + align:start position:0% +meeting you and enjoy playing or not. + + + align:start position:0% +meeting you and enjoy playing or not. +So you want like a aha moment in Euro + + align:start position:0% +So you want like a aha moment in Euro + + + align:start position:0% +So you want like a aha moment in Euro +kind of I think I think you want to get + + align:start position:0% +kind of I think I think you want to get + + + align:start position:0% +kind of I think I think you want to get +away from instruction and more of like + + align:start position:0% +away from instruction and more of like + + + align:start position:0% +away from instruction and more of like +concept, right? So see if you can think + + align:start position:0% +concept, right? So see if you can think + + + align:start position:0% +concept, right? So see if you can think +of a little narrower focus than these + + align:start position:0% +of a little narrower focus than these + + + align:start position:0% +of a little narrower focus than these +big big big concepts and that might help + + align:start position:0% +big big big concepts and that might help + + + align:start position:0% +big big big concepts and that might help +you with your next group. So like you + + align:start position:0% +you with your next group. So like you + + + align:start position:0% +you with your next group. So like you +guys like like some of them are like + + align:start position:0% +guys like like some of them are like + + + align:start position:0% +guys like like some of them are like +like the robots. Yeah. Yeah. So what + + align:start position:0% +like the robots. Yeah. Yeah. So what + + + align:start position:0% +like the robots. Yeah. Yeah. So what +they're doing so we're teaching them Do + + align:start position:0% +they're doing so we're teaching them Do + + + align:start position:0% +they're doing so we're teaching them Do +you need to rotate? No, you're okay. + + align:start position:0% +you need to rotate? No, you're okay. + + + align:start position:0% +you need to rotate? No, you're okay. +What we're doing is we're they're + + align:start position:0% +What we're doing is we're they're + + + align:start position:0% +What we're doing is we're they're +scientists and we're teaching them how + + align:start position:0% +scientists and we're teaching them how + + + align:start position:0% +scientists and we're teaching them how +to make Have you ever looked on cool + + align:start position:0% +to make Have you ever looked on cool + + + align:start position:0% +to make Have you ever looked on cool +videos? was like, "Have you seen um + + align:start position:0% +videos? was like, "Have you seen um + + + align:start position:0% +videos? was like, "Have you seen um +Charlie the Unicorn or you've seen + + align:start position:0% +Charlie the Unicorn or you've seen + + + align:start position:0% +Charlie the Unicorn or you've seen +Charlie?" Charlie or maybe you've seen + + align:start position:0% +Charlie?" Charlie or maybe you've seen + + + align:start position:0% +Charlie?" Charlie or maybe you've seen +um the was it my I used to work with + + align:start position:0% +um the was it my I used to work with + + + align:start position:0% +um the was it my I used to work with +kids your age and they loved that one. + + align:start position:0% +kids your age and they loved that one. + + + align:start position:0% +kids your age and they loved that one. +Um it was about this little snail Marcel + + align:start position:0% +Um it was about this little snail Marcel + + + align:start position:0% +Um it was about this little snail Marcel +the shell. Have you seen that one? No. + + align:start position:0% +the shell. Have you seen that one? No. + + + align:start position:0% +the shell. Have you seen that one? No. +Well, you see these little YouTube + + align:start position:0% +Well, you see these little YouTube + + + align:start position:0% +Well, you see these little YouTube +videos and everyone's like, "Oh, that's + + align:start position:0% +videos and everyone's like, "Oh, that's + + + align:start position:0% +videos and everyone's like, "Oh, that's +cool. You got to watch that, too." + + align:start position:0% +cool. You got to watch that, too." + + + align:start position:0% +cool. You got to watch that, too." +Right. The 21 kid. Which one? The 21 kid + + align:start position:0% +Right. The 21 kid. Which one? The 21 kid + + + align:start position:0% +Right. The 21 kid. Which one? The 21 kid +that says 21. Every everybody in America + + align:start position:0% +that says 21. Every everybody in America + + + align:start position:0% +that says 21. Every everybody in America +says 21 now. Oh, really? Is that Is that + + align:start position:0% +says 21 now. Oh, really? Is that Is that + + + align:start position:0% +says 21 now. Oh, really? Is that Is that +the one you have to watch? 21. It's like + + align:start position:0% +the one you have to watch? 21. It's like + + + align:start position:0% +the one you have to watch? 21. It's like +it's like a vine + + align:start position:0% +it's like a vine + + + align:start position:0% +it's like a vine +and then they make them into a video or + + align:start position:0% +and then they make them into a video or + + + align:start position:0% +and then they make them into a video or +there's um a series of shows in YouTube + + align:start position:0% +there's um a series of shows in YouTube + + + align:start position:0% +there's um a series of shows in YouTube +called ASDF. It's about this little like + + align:start position:0% +called ASDF. It's about this little like + + + align:start position:0% +called ASDF. It's about this little like +stick figures, right? So So you guys see + + align:start position:0% +stick figures, right? So So you guys see + + + align:start position:0% +stick figures, right? So So you guys see +them and then you're like, "Hey friend, + + align:start position:0% +them and then you're like, "Hey friend, + + + align:start position:0% +them and then you're like, "Hey friend, +you've got to see this too." And then + + align:start position:0% +you've got to see this too." And then + + + align:start position:0% +you've got to see this too." And then +you're like, you get everyone to watch + + align:start position:0% +you're like, you get everyone to watch + + + align:start position:0% +you're like, you get everyone to watch +it, right? We're trying to make those + + align:start position:0% +it, right? We're trying to make those + + + align:start position:0% +it, right? We're trying to make those +really cool short videos about science + + align:start position:0% +really cool short videos about science + + + align:start position:0% +really cool short videos about science +topics, right? And so we're going to + + align:start position:0% +topics, right? And so we're going to + + + align:start position:0% +topics, right? And so we're going to +make them free so that anyone so that it + + align:start position:0% +make them free so that anyone so that it + + + align:start position:0% +make them free so that anyone so that it +also teaches people something while it's + + align:start position:0% +also teaches people something while it's + + + align:start position:0% +also teaches people something while it's +also cool and fun, right? Okay. And so + + align:start position:0% +also cool and fun, right? Okay. And so + + + align:start position:0% +also cool and fun, right? Okay. And so +what he's trying to figure out is like + + align:start position:0% +what he's trying to figure out is like + + + align:start position:0% +what he's trying to figure out is like +what in his world of computer science + + align:start position:0% +what in his world of computer science + + + align:start position:0% +what in his world of computer science +would be like cool enough that you'd be + + align:start position:0% +would be like cool enough that you'd be + + + align:start position:0% +would be like cool enough that you'd be +like, "Hey friend, you got to check this + + align:start position:0% +like, "Hey friend, you got to check this + + + align:start position:0% +like, "Hey friend, you got to check this +out. It's really awesome." I think the + + align:start position:0% +out. It's really awesome." I think the + + + align:start position:0% +out. It's really awesome." I think the +hacker one would be good for people our + + align:start position:0% +hacker one would be good for people our + + + align:start position:0% +hacker one would be good for people our +age to understand like how someone + + align:start position:0% +age to understand like how someone + + + align:start position:0% +age to understand like how someone +hacked your account. Yeah. But then you + + align:start position:0% +hacked your account. Yeah. But then you + + + align:start position:0% +hacked your account. Yeah. But then you +don't want then you want kids to hack + + align:start position:0% +don't want then you want kids to hack + + + align:start position:0% +don't want then you want kids to hack +people. Well, that's the fear, right? + + align:start position:0% +people. Well, that's the fear, right? + + + align:start position:0% +people. Well, that's the fear, right? +You don't want to end up giving kids + + align:start position:0% +You don't want to end up giving kids + + + align:start position:0% +You don't want to end up giving kids +instructions on how to hack cuz I don't + + align:start position:0% +instructions on how to hack cuz I don't + + + align:start position:0% +instructions on how to hack cuz I don't +think the government or anyone else + + align:start position:0% +think the government or anyone else + + + align:start position:0% +think the government or anyone else +would probably like that. But but that's + + align:start position:0% +would probably like that. But but that's + + + align:start position:0% +would probably like that. But but that's +a fear, right? is just making sure that + + align:start position:0% +a fear, right? is just making sure that + + + align:start position:0% +a fear, right? is just making sure that +we're not actually giving instructional + + align:start position:0% +we're not actually giving instructional + + + align:start position:0% +we're not actually giving instructional +videos on how to destroy other people's + + align:start position:0% +videos on how to destroy other people's + + + align:start position:0% +videos on how to destroy other people's +credit cards. Google might feel + + align:start position:0% +credit cards. Google might feel + + + align:start position:0% +credit cards. Google might feel +good ATM. + + align:start position:0% +good ATM. + + + align:start position:0% +good ATM. +Yeah. Of make protecting your how to + + align:start position:0% +Yeah. Of make protecting your how to + + + align:start position:0% +Yeah. Of make protecting your how to +protect your like yourself like make + + align:start position:0% +protect your like yourself like make + + + align:start position:0% +protect your like yourself like make +sure your money's safe or something like + + align:start position:0% +sure your money's safe or something like + + + align:start position:0% +sure your money's safe or something like +that would be like how to protect + + align:start position:0% +that would be like how to protect + + + align:start position:0% +that would be like how to protect +yourself from hackers. How to protect + + align:start position:0% +yourself from hackers. How to protect + + + align:start position:0% +yourself from hackers. How to protect +how to protect yourself is instead of + + align:start position:0% +how to protect yourself is instead of + + + align:start position:0% +how to protect yourself is instead of +like destroying someone else's + + align:start position:0% +like destroying someone else's + + + align:start position:0% +like destroying someone else's +something. It was a nice way of + + align:start position:0% +something. It was a nice way of + + + align:start position:0% +something. It was a nice way of +learning. So say if someone lost their + + align:start position:0% +learning. So say if someone lost their + + + align:start position:0% +learning. So say if someone lost their +um wallet and they had their credit card + + align:start position:0% +um wallet and they had their credit card + + + align:start position:0% +um wallet and they had their credit card +in there and they can access to the bank + + align:start position:0% +in there and they can access to the bank + + + align:start position:0% +in there and they can access to the bank +is that the person if someone found it + + align:start position:0% +is that the person if someone found it + + + align:start position:0% +is that the person if someone found it +and the person access do do they end up + + align:start position:0% +and the person access do do they end up + + + align:start position:0% +and the person access do do they end up +giving them the money sometimes and + + align:start position:0% +giving them the money sometimes and + + + align:start position:0% +giving them the money sometimes and +that's why credit cards are really good + + align:start position:0% +that's why credit cards are really good + + + align:start position:0% +that's why credit cards are really good +at being do you know anything about this + + align:start position:0% +at being do you know anything about this + + + align:start position:0% +at being do you know anything about this +in your work or no? um credit cards, + + align:start position:0% +in your work or no? um credit cards, + + + align:start position:0% +in your work or no? um credit cards, +credit card like protecting credit card + + align:start position:0% +credit card like protecting credit card + + + align:start position:0% +credit card like protecting credit card +identity and all that, but don't they + + align:start position:0% +identity and all that, but don't they + + + align:start position:0% +identity and all that, but don't they +have like your picture or something so + + align:start position:0% +have like your picture or something so + + + align:start position:0% +have like your picture or something so +they know? It's like But online you it's + + align:start position:0% +they know? It's like But online you it's + + + align:start position:0% +they know? It's like But online you it's +really easy to like use another person's + + align:start position:0% +really easy to like use another person's + + + align:start position:0% +really easy to like use another person's +credit card if you know all the + + align:start position:0% +credit card if you know all the + + + align:start position:0% +credit card if you know all the +information. Yeah, it's kind of like I + + align:start position:0% +information. Yeah, it's kind of like I + + + align:start position:0% +information. Yeah, it's kind of like I +get called often from my bank saying did + + align:start position:0% +get called often from my bank saying did + + + align:start position:0% +get called often from my bank saying did +you make this purchase or did someone + + align:start position:0% +you make this purchase or did someone + + + align:start position:0% +you make this purchase or did someone +else? Um but that's an interesting thing + + align:start position:0% +else? Um but that's an interesting thing + + + align:start position:0% +else? Um but that's an interesting thing +for people who who do a lot of shopping + + align:start position:0% +for people who who do a lot of shopping + + + align:start position:0% +for people who who do a lot of shopping +online. How do you protect yourself? If + + align:start position:0% +online. How do you protect yourself? If + + + align:start position:0% +online. How do you protect yourself? If +somebody else took your money, would you + + align:start position:0% +somebody else took your money, would you + + + align:start position:0% +somebody else took your money, would you +get that back or no? + + align:start position:0% +get that back or no? + + + align:start position:0% +get that back or no? +That's why if you catch it quickly with + + align:start position:0% +That's why if you catch it quickly with + + + align:start position:0% +That's why if you catch it quickly with +your bank, sometimes they can they can + + align:start position:0% +your bank, sometimes they can they can + + + align:start position:0% +your bank, sometimes they can they can +quickly stop it before it ends up + + align:start position:0% +quickly stop it before it ends up + + + align:start position:0% +quickly stop it before it ends up +getting charged to you. But that's an + + align:start position:0% +getting charged to you. But that's an + + + align:start position:0% +getting charged to you. But that's an +interesting idea is how do you how do + + align:start position:0% +interesting idea is how do you how do + + + align:start position:0% +interesting idea is how do you how do +you if you're buying stuff on this on + + align:start position:0% +you if you're buying stuff on this on + + + align:start position:0% +you if you're buying stuff on this on +the internet like what's actually + + align:start position:0% +the internet like what's actually + + + align:start position:0% +the internet like what's actually +happening to protect yourself? What if + + align:start position:0% +happening to protect yourself? What if + + + align:start position:0% +happening to protect yourself? What if +um like someone like um um like if they + + align:start position:0% +um like someone like um um like if they + + + align:start position:0% +um like someone like um um like if they +did if they did like catch the person + + align:start position:0% +did if they did like catch the person + + + align:start position:0% +did if they did like catch the person +and the person already used all the + + align:start position:0% +and the person already used all the + + + align:start position:0% +and the person already used all the +money and that you can't like return it + + align:start position:0% +money and that you can't like return it + + + align:start position:0% +money and that you can't like return it +after that? Did the bank end up giving + + align:start position:0% +after that? Did the bank end up giving + + + align:start position:0% +after that? Did the bank end up giving +like their money to Do you ever wonder + + align:start position:0% +like their money to Do you ever wonder + + + align:start position:0% +like their money to Do you ever wonder +what happens when you type in the credit + + align:start position:0% +what happens when you type in the credit + + + align:start position:0% +what happens when you type in the credit +card number and like how the money + + align:start position:0% +card number and like how the money + + + align:start position:0% +card number and like how the money +actually gets where it needs to go? Oh, + + align:start position:0% +actually gets where it needs to go? Oh, + + + align:start position:0% +actually gets where it needs to go? Oh, +they um track them down. Like have you + + align:start position:0% +they um track them down. Like have you + + + align:start position:0% +they um track them down. Like have you +ever wondered about how that happens? + + align:start position:0% +ever wondered about how that happens? + + + align:start position:0% +ever wondered about how that happens? +No, not really. You just care about + + align:start position:0% +No, not really. You just care about + + + align:start position:0% +No, not really. You just care about +getting your package. Um do + + align:start position:0% +getting your package. Um do + + + align:start position:0% +getting your package. Um do +they ATM make the money or do they put + + align:start position:0% +they ATM make the money or do they put + + + align:start position:0% +they ATM make the money or do they put +it in? + + align:start position:0% +it in? + + + align:start position:0% +it in? +Do they just put the money in there? + + align:start position:0% +Do they just put the money in there? + + + align:start position:0% +Do they just put the money in there? +There's a whole every country is + + align:start position:0% +There's a whole every country is + + + align:start position:0% +There's a whole every country is +different but at least here um there's a + + align:start position:0% +different but at least here um there's a + + + align:start position:0% +different but at least here um there's a +central office that makes money and then + + align:start position:0% +central office that makes money and then + + + align:start position:0% +central office that makes money and then +they just distribute it into different + + align:start position:0% +they just distribute it into different + + + align:start position:0% +they just distribute it into different +places. Them doesn't make the money. + + align:start position:0% +places. Them doesn't make the money. + + + align:start position:0% +places. Them doesn't make the money. +It's a good question. But interesting + + align:start position:0% +It's a good question. But interesting + + + align:start position:0% +It's a good question. But interesting +thing for you to think about is sort of + + align:start position:0% +thing for you to think about is sort of + + + align:start position:0% +thing for you to think about is sort of +what within these topics more + + align:start position:0% +what within these topics more + + + align:start position:0% +what within these topics more +specifically because the hacking is a + + align:start position:0% +specifically because the hacking is a + + + align:start position:0% +specifically because the hacking is a +cool topic, but you're right, it's a + + align:start position:0% +cool topic, but you're right, it's a + + + align:start position:0% +cool topic, but you're right, it's a +dangerous one and we'd want to make sure + + align:start position:0% +dangerous one and we'd want to make sure + + + align:start position:0% +dangerous one and we'd want to make sure +we had the right angle so that we're not + + align:start position:0% +we had the right angle so that we're not + + + align:start position:0% +we had the right angle so that we're not +accidentally giving sixth graders the + + align:start position:0% +accidentally giving sixth graders the + + + align:start position:0% +accidentally giving sixth graders the +tools to be able to hack into whatever + + align:start position:0% +tools to be able to hack into whatever + + + align:start position:0% +tools to be able to hack into whatever +account, right? That would be scary. + + align:start position:0% +account, right? That would be scary. + + + align:start position:0% +account, right? That would be scary. +Google might be a good one. Could be, + + align:start position:0% +Google might be a good one. Could be, + + + align:start position:0% +Google might be a good one. Could be, +right? How does Google actually work? + + align:start position:0% +right? How does Google actually work? + + + align:start position:0% +right? How does Google actually work? +How does it find your result? Like if + + align:start position:0% +How does it find your result? Like if + + + align:start position:0% +How does it find your result? Like if +you want to learn how zebras have + + align:start position:0% +you want to learn how zebras have + + + align:start position:0% +you want to learn how zebras have +stripes, how does it actually give you + + align:start position:0% +stripes, how does it actually give you + + + align:start position:0% +stripes, how does it actually give you +an answer? Like how does + + align:start position:0% +an answer? Like how does + + + align:start position:0% +an answer? Like how does +like spread like a virus? Like + + align:start position:0% +like spread like a virus? Like + + + align:start position:0% +like spread like a virus? Like +that's a cool idea, too. Something to + + align:start position:0% +that's a cool idea, too. Something to + + + align:start position:0% +that's a cool idea, too. Something to +think about. Keep thinking. You're on + + align:start position:0% +think about. Keep thinking. You're on + + + align:start position:0% +think about. Keep thinking. You're on +it. Good, good, good. + + align:start position:0% +it. Good, good, good. + + + align:start position:0% +it. Good, good, good. +And you are Anama. Anemma. Anama. Nema. + + align:start position:0% +And you are Anama. Anemma. Anama. Nema. + + + align:start position:0% +And you are Anama. Anemma. Anama. Nema. +Okay. Two really cool names. Yeah. Thank + + align:start position:0% +Okay. Two really cool names. Yeah. Thank + + + align:start position:0% +Okay. Two really cool names. Yeah. Thank +you. And Giana. Giana. So, we're going + + align:start position:0% +you. And Giana. Giana. So, we're going + + + align:start position:0% +you. And Giana. Giana. So, we're going +to have to move a little quick because + + align:start position:0% +to have to move a little quick because + + + align:start position:0% +to have to move a little quick because +we got two teams to talk about. So, you + + align:start position:0% +we got two teams to talk about. So, you + + + align:start position:0% +we got two teams to talk about. So, you +go first. Um, okay. Introduction first. + + align:start position:0% +go first. Um, okay. Introduction first. + + + align:start position:0% +go first. Um, okay. Introduction first. +Um, I'm a first year here at MIT. I like + + align:start position:0% +Um, I'm a first year here at MIT. I like + + + align:start position:0% +Um, I'm a first year here at MIT. I like +to study math, uh, physics and + + align:start position:0% +to study math, uh, physics and + + + align:start position:0% +to study math, uh, physics and +education. I said it's too much. Um, + + align:start position:0% +education. I said it's too much. Um, + + + align:start position:0% +education. I said it's too much. Um, +and, um, I'm going to just pitch the + + align:start position:0% +and, um, I'm going to just pitch the + + + align:start position:0% +and, um, I'm going to just pitch the +idea right away. Normally, I would ask + + align:start position:0% +idea right away. Normally, I would ask + + + align:start position:0% +idea right away. Normally, I would ask +you guys what you like. Um, but the + + align:start position:0% +you guys what you like. Um, but the + + + align:start position:0% +you guys what you like. Um, but the +question that I would like to discuss in + + align:start position:0% +question that I would like to discuss in + + + align:start position:0% +question that I would like to discuss in +a video + + align:start position:0% +a video + + + align:start position:0% +a video +is whether math is actually real and + + align:start position:0% +is whether math is actually real and + + + align:start position:0% +is whether math is actually real and +true. And the thing is that + + align:start position:0% +true. And the thing is that + + + align:start position:0% +true. And the thing is that +mathematicians have proved that they can + + align:start position:0% +mathematicians have proved that they can + + + align:start position:0% +mathematicians have proved that they can +never prove that. So we can never know + + align:start position:0% +never prove that. So we can never know + + + align:start position:0% +never prove that. So we can never know +for sure if math is true. Even + + align:start position:0% +for sure if math is true. Even + + + align:start position:0% +for sure if math is true. Even +arithmetic, you know, it's worked for us + + align:start position:0% +arithmetic, you know, it's worked for us + + + align:start position:0% +arithmetic, you know, it's worked for us +so well. You know, t plus 2 is always + + align:start position:0% +so well. You know, t plus 2 is always + + + align:start position:0% +so well. You know, t plus 2 is always +four, it seems, + + align:start position:0% +four, it seems, + + + align:start position:0% +four, it seems, +but that may not be true. Um, so I guess + + align:start position:0% +but that may not be true. Um, so I guess + + + align:start position:0% +but that may not be true. Um, so I guess +that's kind of the question I wanted to + + align:start position:0% +that's kind of the question I wanted to + + + align:start position:0% +that's kind of the question I wanted to +address. And out of that, it also comes, + + align:start position:0% +address. And out of that, it also comes, + + + align:start position:0% +address. And out of that, it also comes, +you know, can machines be smarter than + + align:start position:0% +you know, can machines be smarter than + + + align:start position:0% +you know, can machines be smarter than +humans? And, you know, can robots + + align:start position:0% +humans? And, you know, can robots + + + align:start position:0% +humans? And, you know, can robots +overtake the world. So just things like + + align:start position:0% +overtake the world. So just things like + + + align:start position:0% +overtake the world. So just things like +that. Um, so any thoughts? Which one? So + + align:start position:0% +that. Um, so any thoughts? Which one? So + + + align:start position:0% +that. Um, so any thoughts? Which one? So +those were three topics, right? Um, so + + align:start position:0% +those were three topics, right? Um, so + + + align:start position:0% +those were three topics, right? Um, so +that was one topic. one topic like just + + align:start position:0% +that was one topic. one topic like just + + + align:start position:0% +that was one topic. one topic like just +like all those questions kind of come + + align:start position:0% +like all those questions kind of come + + + align:start position:0% +like all those questions kind of come +out of that. + + align:start position:0% +out of that. + + + align:start position:0% +out of that. +Those are big questions. + + align:start position:0% + + + + align:start position:0% + +What do you guys respond? Do you think + + align:start position:0% +What do you guys respond? Do you think + + + align:start position:0% +What do you guys respond? Do you think +any of those ideas that she mentioned + + align:start position:0% +any of those ideas that she mentioned + + + align:start position:0% +any of those ideas that she mentioned +are things that you would be like, "Hey, + + align:start position:0% +are things that you would be like, "Hey, + + + align:start position:0% +are things that you would be like, "Hey, +friend. This is really cool. You got to + + align:start position:0% +friend. This is really cool. You got to + + + align:start position:0% +friend. This is really cool. You got to +check out this video." Mhm. Yeah. Which + + align:start position:0% +check out this video." Mhm. Yeah. Which + + + align:start position:0% +check out this video." Mhm. Yeah. Which +one? The robot thing. The robot. Would + + align:start position:0% +one? The robot thing. The robot. Would + + + align:start position:0% +one? The robot thing. The robot. Would +robots take over the world? They're all + + align:start position:0% +robots take over the world? They're all + + + align:start position:0% +robots take over the world? They're all +related, you know. I like the one that + + align:start position:0% +related, you know. I like the one that + + + align:start position:0% +related, you know. I like the one that +is like Is it like true is like for It's + + align:start position:0% +is like Is it like true is like for It's + + + align:start position:0% +is like Is it like true is like for It's +like like for like eight. Is that true? + + align:start position:0% +like like for like eight. Is that true? + + + align:start position:0% +like like for like eight. Is that true? +Okay. So, I'll I'll tell you a secret. + + align:start position:0% +Okay. So, I'll I'll tell you a secret. + + + align:start position:0% +Okay. So, I'll I'll tell you a secret. +Even though we cannot tell that math is + + align:start position:0% +Even though we cannot tell that math is + + + align:start position:0% +Even though we cannot tell that math is +true, that's sad. That also means that + + align:start position:0% +true, that's sad. That also means that + + + align:start position:0% +true, that's sad. That also means that +robots cannot overtake the world. In + + align:start position:0% +robots cannot overtake the world. In + + + align:start position:0% +robots cannot overtake the world. In +case possible, it's not answer. Changing + + align:start position:0% +case possible, it's not answer. Changing + + + align:start position:0% +case possible, it's not answer. Changing +it to math. The math one, but you'll get + + align:start position:0% +it to math. The math one, but you'll get + + + align:start position:0% +it to math. The math one, but you'll get +to the math one through the robots one, + + align:start position:0% +to the math one through the robots one, + + + align:start position:0% +to the math one through the robots one, +right? So, you could Did you have any + + align:start position:0% +right? So, you could Did you have any + + + align:start position:0% +right? So, you could Did you have any +other ideas or was this like the big + + align:start position:0% +other ideas or was this like the big + + + align:start position:0% +other ideas or was this like the big +idea? Uh, that was the that was the big + + align:start position:0% +idea? Uh, that was the that was the big + + + align:start position:0% +idea? Uh, that was the that was the big +one. So, you think that if she talks + + align:start position:0% +one. So, you think that if she talks + + + align:start position:0% +one. So, you think that if she talks +about the idea of could robots overtake + + align:start position:0% +about the idea of could robots overtake + + + align:start position:0% +about the idea of could robots overtake +the world and through that she answers + + align:start position:0% +the world and through that she answers + + + align:start position:0% +the world and through that she answers +some of the questions about math being + + align:start position:0% +some of the questions about math being + + + align:start position:0% +some of the questions about math being +true or not true, that would be really + + align:start position:0% +true or not true, that would be really + + + align:start position:0% +true or not true, that would be really +cool? Yes. I don't think robots can take + + align:start position:0% +cool? Yes. I don't think robots can take + + + align:start position:0% +cool? Yes. I don't think robots can take +over the world. You don't think so? They + + align:start position:0% +over the world. You don't think so? They + + + align:start position:0% +over the world. You don't think so? They +because Wait, what about that weird + + align:start position:0% +because Wait, what about that weird + + + align:start position:0% +because Wait, what about that weird +robot the face of that thing? I mean, + + align:start position:0% +robot the face of that thing? I mean, + + + align:start position:0% +robot the face of that thing? I mean, +you can smash them and they break. But + + align:start position:0% +you can smash them and they break. But + + + align:start position:0% +you can smash them and they break. But +what if they try to smash you? + + align:start position:0% +what if they try to smash you? + + + align:start position:0% +what if they try to smash you? +So eventually we'll be smarter because + + align:start position:0% +So eventually we'll be smarter because + + + align:start position:0% +So eventually we'll be smarter because +that's kind of what a mathematician + + align:start position:0% +that's kind of what a mathematician + + + align:start position:0% +that's kind of what a mathematician +proved is that a machine can never be as + + align:start position:0% +proved is that a machine can never be as + + + align:start position:0% +proved is that a machine can never be as +smart as a human or do as many things + + align:start position:0% +smart as a human or do as many things + + + align:start position:0% +smart as a human or do as many things +that we can do. So you guys said could + + align:start position:0% +that we can do. So you guys said could + + + align:start position:0% +that we can do. So you guys said could +robots take over the world idea with all + + align:start position:0% +robots take over the world idea with all + + + align:start position:0% +robots take over the world idea with all +this other stuff connected to it. I + + align:start position:0% +this other stuff connected to it. I + + + align:start position:0% +this other stuff connected to it. I +think that's a cool idea. Do you know + + align:start position:0% +think that's a cool idea. Do you know + + + align:start position:0% +think that's a cool idea. Do you know +the um show Lab Rats? No, I don't. Well, + + align:start position:0% +the um show Lab Rats? No, I don't. Well, + + + align:start position:0% +the um show Lab Rats? No, I don't. Well, +there was like these three humans who + + align:start position:0% +there was like these three humans who + + + align:start position:0% +there was like these three humans who +are like also like um a robot thing and + + align:start position:0% +are like also like um a robot thing and + + + align:start position:0% +are like also like um a robot thing and +they have like all kinds of powers and + + align:start position:0% +they have like all kinds of powers and + + + align:start position:0% +they have like all kinds of powers and +and because there's this guy that wanted + + align:start position:0% +and because there's this guy that wanted + + + align:start position:0% +and because there's this guy that wanted +to make them evil and like take over the + + align:start position:0% +to make them evil and like take over the + + + align:start position:0% +to make them evil and like take over the +world. Not Disney Channel + + align:start position:0% +world. Not Disney Channel + + + align:start position:0% +world. Not Disney Channel +and and then like this person stole them + + align:start position:0% +and and then like this person stole them + + + align:start position:0% +and and then like this person stole them +and make them became heroes. But can + + align:start position:0% +and make them became heroes. But can + + + align:start position:0% +and make them became heroes. But can +what if like someone that invents a + + align:start position:0% +what if like someone that invents a + + + align:start position:0% +what if like someone that invents a +robot gives them all kinds of like Yeah, + + align:start position:0% +robot gives them all kinds of like Yeah, + + + align:start position:0% +robot gives them all kinds of like Yeah, +that's what she was saying that robots + + align:start position:0% +that's what she was saying that robots + + + align:start position:0% +that's what she was saying that robots +can be really really smart but not as + + align:start position:0% +can be really really smart but not as + + + align:start position:0% +can be really really smart but not as +smart as us. So, I guess eventually + + align:start position:0% +smart as us. So, I guess eventually + + + align:start position:0% +smart as us. So, I guess eventually +we'll win if robots do decide to break + + align:start position:0% +we'll win if robots do decide to break + + + align:start position:0% +we'll win if robots do decide to break +down on us. I want to make sure Andrea + + align:start position:0% +down on us. I want to make sure Andrea + + + align:start position:0% +down on us. I want to make sure Andrea +gets some time. So, let's hear your + + align:start position:0% +gets some time. So, let's hear your + + + align:start position:0% +gets some time. So, let's hear your +ideas. So, you guys have an I'll go get + + align:start position:0% +ideas. So, you guys have an I'll go get + + + align:start position:0% +ideas. So, you guys have an I'll go get +you some. You keep going. Okay. I'm + + align:start position:0% +you some. You keep going. Okay. I'm + + + align:start position:0% +you some. You keep going. Okay. I'm +sorry about that. It's okay. + + align:start position:0% +sorry about that. It's okay. + + + align:start position:0% +sorry about that. It's okay. +So, um I already know the answer for + + align:start position:0% +So, um I already know the answer for + + + align:start position:0% +So, um I already know the answer for +you. Are you going to have to have + + align:start position:0% +you. Are you going to have to have + + + align:start position:0% +you. Are you going to have to have +braces someday? Do you know? No. No. I + + align:start position:0% +braces someday? Do you know? No. No. I + + + align:start position:0% +braces someday? Do you know? No. No. I +want They're cool. They look cool. You + + align:start position:0% +want They're cool. They look cool. You + + + align:start position:0% +want They're cool. They look cool. You +want them? No. Kind of. No, I don't. No, + + align:start position:0% +want them? No. Kind of. No, I don't. No, + + + align:start position:0% +want them? No. Kind of. No, I don't. No, +you don't. + + align:start position:0% +you don't. + + + align:start position:0% +you don't. +So, what how long have you had your + + align:start position:0% +So, what how long have you had your + + + align:start position:0% +So, what how long have you had your +braces? + + align:start position:0% +braces? + + + align:start position:0% +braces? +Beginning of fifth grade. So, you've had + + align:start position:0% +Beginning of fifth grade. So, you've had + + + align:start position:0% +Beginning of fifth grade. So, you've had +them a while. Yeah. I don't even know if + + align:start position:0% +them a while. Yeah. I don't even know if + + + align:start position:0% +them a while. Yeah. I don't even know if +I want braces cuz you can't eat gum or + + align:start position:0% +I want braces cuz you can't eat gum or + + + align:start position:0% +I want braces cuz you can't eat gum or +anything. + + align:start position:0% +anything. + + + align:start position:0% +anything. +No, I don't. I do. + + align:start position:0% +No, I don't. I do. + + + align:start position:0% +No, I don't. I do. +So, are you curious about like what they + + align:start position:0% +So, are you curious about like what they + + + align:start position:0% +So, are you curious about like what they +do to your teeth? Make them straight, I + + align:start position:0% +do to your teeth? Make them straight, I + + + align:start position:0% +do to your teeth? Make them straight, I +guess. Do you know how do you know how + + align:start position:0% +guess. Do you know how do you know how + + + align:start position:0% +guess. Do you know how do you know how +they do that? Yeah, they put them They + + align:start position:0% +they do that? Yeah, they put them They + + + align:start position:0% +they do that? Yeah, they put them They +put them together. + + align:start position:0% +put them together. + + + align:start position:0% +put them together. +That made them straighten. I had like + + align:start position:0% +That made them straighten. I had like + + + align:start position:0% +That made them straighten. I had like +two teeth up here. Hold them down, + + align:start position:0% +two teeth up here. Hold them down, + + + align:start position:0% +two teeth up here. Hold them down, +right? Yeah. You have two teeth that + + align:start position:0% +right? Yeah. You have two teeth that + + + align:start position:0% +right? Yeah. You have two teeth that +flipped out. I had a pallet expander, + + align:start position:0% +flipped out. I had a pallet expander, + + + align:start position:0% +flipped out. I had a pallet expander, +too, that they took out a couple months + + align:start position:0% +too, that they took out a couple months + + + align:start position:0% +too, that they took out a couple months +ago. Tissue. You're going to make me + + align:start position:0% +ago. Tissue. You're going to make me + + + align:start position:0% +ago. Tissue. You're going to make me +talk like like like that. I couldn't + + align:start position:0% +talk like like like that. I couldn't + + + align:start position:0% +talk like like like that. I couldn't +talk for a while. It's like widening my + + align:start position:0% +talk for a while. It's like widening my + + + align:start position:0% +talk for a while. It's like widening my +jaw. + + align:start position:0% +jaw. + + + align:start position:0% +jaw. +I had to key it everywhere. It kind of + + align:start position:0% +I had to key it everywhere. It kind of + + + align:start position:0% +I had to key it everywhere. It kind of +hurt. You don't want braces. + + align:start position:0% +hurt. You don't want braces. + + + align:start position:0% +hurt. You don't want braces. +What was it? I'm sorry I missed it. What + + align:start position:0% +What was it? I'm sorry I missed it. What + + + align:start position:0% +What was it? I'm sorry I missed it. What +was your idea? um to talk about braces. + + align:start position:0% +was your idea? um to talk about braces. + + + align:start position:0% +was your idea? um to talk about braces. +Basically, what they're doing to your + + align:start position:0% +Basically, what they're doing to your + + + align:start position:0% +Basically, what they're doing to your +teeth. Oh, that's cool. Are they bad for + + align:start position:0% +teeth. Oh, that's cool. Are they bad for + + + align:start position:0% +teeth. Oh, that's cool. Are they bad for +your teeth also? Are they bad for your + + align:start position:0% +your teeth also? Are they bad for your + + + align:start position:0% +your teeth also? Are they bad for your +teeth? That's a good question. Why did + + align:start position:0% +teeth? That's a good question. Why did + + + align:start position:0% +teeth? That's a good question. Why did +my teeth move back? Why did my gum like + + align:start position:0% +my teeth move back? Why did my gum like + + + align:start position:0% +my teeth move back? Why did my gum like +scratches everything? What happens when + + align:start position:0% +scratches everything? What happens when + + + align:start position:0% +scratches everything? What happens when +stuff gets Oh, I just I just got my + + align:start position:0% +stuff gets Oh, I just I just got my + + + align:start position:0% +stuff gets Oh, I just I just got my +braces off in October. Good for you. My + + align:start position:0% +braces off in October. Good for you. My + + + align:start position:0% +braces off in October. Good for you. My +dad hasn't hooked me to get them changed + + align:start position:0% +dad hasn't hooked me to get them changed + + + align:start position:0% +dad hasn't hooked me to get them changed +every month, but it's been like 3 + + align:start position:0% +every month, but it's been like 3 + + + align:start position:0% +every month, but it's been like 3 +months. Yeah. So, what's actually going + + align:start position:0% +months. Yeah. So, what's actually going + + + align:start position:0% +months. Yeah. So, what's actually going +on with your braces? That's a cool, very + + align:start position:0% +on with your braces? That's a cool, very + + + align:start position:0% +on with your braces? That's a cool, very +age relevant topic. Wait, instead of + + align:start position:0% +age relevant topic. Wait, instead of + + + align:start position:0% +age relevant topic. Wait, instead of +getting braces, can't you get that like + + align:start position:0% +getting braces, can't you get that like + + + align:start position:0% +getting braces, can't you get that like +plastic thing? Yeah, the the aligners. + + align:start position:0% +plastic thing? Yeah, the the aligners. + + + align:start position:0% +plastic thing? Yeah, the the aligners. +Yeah, I have. Do you know if I have to + + align:start position:0% +Yeah, I have. Do you know if I have to + + + align:start position:0% +Yeah, I have. Do you know if I have to +get a retainer? I have to wear a + + align:start position:0% +get a retainer? I have to wear a + + + align:start position:0% +get a retainer? I have to wear a +retainer. + + align:start position:0% +retainer. + + + align:start position:0% +retainer. +I know one of my friends who had them + + align:start position:0% +I know one of my friends who had them + + + align:start position:0% +I know one of my friends who had them +who like still wears this retainer. Do + + align:start position:0% +who like still wears this retainer. Do + + + align:start position:0% +who like still wears this retainer. Do +you have to like wear it every day or if + + align:start position:0% +you have to like wear it every day or if + + + align:start position:0% +you have to like wear it every day or if +you don't wear every night? Every night + + align:start position:0% +you don't wear every night? Every night + + + align:start position:0% +you don't wear every night? Every night +of that actually for the rest of your + + align:start position:0% +of that actually for the rest of your + + + align:start position:0% +of that actually for the rest of your +life that if you don't wear your + + align:start position:0% +life that if you don't wear your + + + align:start position:0% +life that if you don't wear your +retainer, your teeth wear it from + + align:start position:0% +retainer, your teeth wear it from + + + align:start position:0% +retainer, your teeth wear it from +school. I just hear stuff about you have + + align:start position:0% +school. I just hear stuff about you have + + + align:start position:0% +school. I just hear stuff about you have +to wear the rest of your life. + + align:start position:0% +to wear the rest of your life. + + + align:start position:0% +to wear the rest of your life. +See, I still wear retainers at night. + + align:start position:0% +See, I still wear retainers at night. + + + align:start position:0% +See, I still wear retainers at night. +And I don't understand they give kids + + align:start position:0% +And I don't understand they give kids + + + align:start position:0% +And I don't understand they give kids +braces so young now. Like you can be in + + align:start position:0% +braces so young now. Like you can be in + + + align:start position:0% +braces so young now. Like you can be in +third grade and have braces, whereas + + align:start position:0% +third grade and have braces, whereas + + + align:start position:0% +third grade and have braces, whereas +when I was a kid, you didn't get them + + align:start position:0% +when I was a kid, you didn't get them + + + align:start position:0% +when I was a kid, you didn't get them +until like high school. Third grade? + + align:start position:0% +until like high school. Third grade? + + + align:start position:0% +until like high school. Third grade? +Yeah. I mean, do they I I've seen lots + + align:start position:0% +Yeah. I mean, do they I I've seen lots + + + align:start position:0% +Yeah. I mean, do they I I've seen lots +of little kids with braces and you're + + align:start position:0% +of little kids with braces and you're + + + align:start position:0% +of little kids with braces and you're +like, "Your teeth are so little." Yeah. + + align:start position:0% +like, "Your teeth are so little." Yeah. + + + align:start position:0% +like, "Your teeth are so little." Yeah. +You have to wear um retainers every for + + align:start position:0% +You have to wear um retainers every for + + + align:start position:0% +You have to wear um retainers every for +the rest of your life. For a while. What + + align:start position:0% +the rest of your life. For a while. What + + + align:start position:0% +the rest of your life. For a while. What +about + + align:start position:0% +about + + + align:start position:0% +about +the head gear? The head gear. Oh, I like + + align:start position:0% +the head gear? The head gear. Oh, I like + + + align:start position:0% +the head gear? The head gear. Oh, I like +that. That's so gross. + + align:start position:0% +that. That's so gross. + + + align:start position:0% +that. That's so gross. +It looks weird. Charlie. Yeah. Yeah. + + align:start position:0% +It looks weird. Charlie. Yeah. Yeah. + + + align:start position:0% +It looks weird. Charlie. Yeah. Yeah. +Where wears. + + align:start position:0% + + + + align:start position:0% + +It makes you talk weird, too. We're + + align:start position:0% +It makes you talk weird, too. We're + + + align:start position:0% +It makes you talk weird, too. We're +actually really good on Would you do + + align:start position:0% +actually really good on Would you do + + + align:start position:0% +actually really good on Would you do +Would you If you like + + align:start position:0% +Would you If you like + + + align:start position:0% +Would you If you like +everybody, what are you doing? + + align:start position:0% + + + + align:start position:0% + +I heard some amazing conversations and + + align:start position:0% +I heard some amazing conversations and + + + align:start position:0% +I heard some amazing conversations and +you sixth graders asked fantastic + + align:start position:0% +you sixth graders asked fantastic + + + align:start position:0% +you sixth graders asked fantastic +questions. As we're just wrapping up, + + align:start position:0% +questions. As we're just wrapping up, + + + align:start position:0% +questions. As we're just wrapping up, +I'd love to hear from a couple groups of + + align:start position:0% +I'd love to hear from a couple groups of + + + align:start position:0% +I'd love to hear from a couple groups of +the students, the sixth graders. What + + align:start position:0% +the students, the sixth graders. What + + + align:start position:0% +the students, the sixth graders. What +were some of the best ideas that you + + align:start position:0% +were some of the best ideas that you + + + align:start position:0% +were some of the best ideas that you +heard all day that you're like, I can't + + align:start position:0% +heard all day that you're like, I can't + + + align:start position:0% +heard all day that you're like, I can't +wait for this video to come out. I + + align:start position:0% +wait for this video to come out. I + + + align:start position:0% +wait for this video to come out. I +really want to watch it. Any of you hear + + align:start position:0% +really want to watch it. Any of you hear + + + align:start position:0% +really want to watch it. Any of you hear +any like ideas that you're really + + align:start position:0% +any like ideas that you're really + + + align:start position:0% +any like ideas that you're really +excited about? Yeah. Navy one. The Navy + + align:start position:0% +excited about? Yeah. Navy one. The Navy + + + align:start position:0% +excited about? Yeah. Navy one. The Navy +one. What about it? Which what what did + + align:start position:0% +one. What about it? Which what what did + + + align:start position:0% +one. What about it? Which what what did +he Torpedoes? + + align:start position:0% +he Torpedoes? + + + align:start position:0% +he Torpedoes? +Torpedoes. Interesting. The idea of + + align:start position:0% +Torpedoes. Interesting. The idea of + + + align:start position:0% +Torpedoes. Interesting. The idea of +watching things blow up is exciting to + + align:start position:0% +watching things blow up is exciting to + + + align:start position:0% +watching things blow up is exciting to +you. Yes. What else? I like the idea + + align:start position:0% +you. Yes. What else? I like the idea + + + align:start position:0% +you. Yes. What else? I like the idea +with the robot and like we would talk + + align:start position:0% +with the robot and like we would talk + + + align:start position:0% +with the robot and like we would talk +and like we could with Wi-Fi and stuff + + align:start position:0% +and like we could with Wi-Fi and stuff + + + align:start position:0% +and like we could with Wi-Fi and stuff +and you can play with it, run around + + align:start position:0% +and you can play with it, run around + + + align:start position:0% +and you can play with it, run around +with it. I like to see it. So, you're + + align:start position:0% +with it. I like to see it. So, you're + + + align:start position:0% +with it. I like to see it. So, you're +excited about learning more about robots + + align:start position:0% +excited about learning more about robots + + + align:start position:0% +excited about learning more about robots +and how they work? Yeah. Awesome. Anyone + + align:start position:0% +and how they work? Yeah. Awesome. Anyone + + + align:start position:0% +and how they work? Yeah. Awesome. Anyone +else have one? Tiana? Yeah, I have + + align:start position:0% +else have one? Tiana? Yeah, I have + + + align:start position:0% +else have one? Tiana? Yeah, I have +three. Pick one. Pick your best. + + align:start position:0% +three. Pick one. Pick your best. + + + align:start position:0% +three. Pick one. Pick your best. +I like the braces. Yeah, braces. + + align:start position:0% +I like the braces. Yeah, braces. + + + align:start position:0% +I like the braces. Yeah, braces. +Understanding what braces do your teeth + + align:start position:0% +Understanding what braces do your teeth + + + align:start position:0% +Understanding what braces do your teeth +and how they work. That's cool because + + align:start position:0% +and how they work. That's cool because + + + align:start position:0% +and how they work. That's cool because +you've got braces. So that that would be + + align:start position:0% +you've got braces. So that that would be + + + align:start position:0% +you've got braces. So that that would be +interesting. Um, someone said like + + align:start position:0% +interesting. Um, someone said like + + + align:start position:0% +interesting. Um, someone said like +something about volcanoes. The + + align:start position:0% +something about volcanoes. The + + + align:start position:0% +something about volcanoes. The +volcanoes, understanding if there's a + + align:start position:0% +volcanoes, understanding if there's a + + + align:start position:0% +volcanoes, understanding if there's a +volcano underneath your house. That was + + align:start position:0% +volcano underneath your house. That was + + + align:start position:0% +volcano underneath your house. That was +a cool idea. Is there lava under my + + align:start position:0% +a cool idea. Is there lava under my + + + align:start position:0% +a cool idea. Is there lava under my +house? Right. Yikes. Any sixth graders, + + align:start position:0% +house? Right. Yikes. Any sixth graders, + + + align:start position:0% +house? Right. Yikes. Any sixth graders, +any advice to our MIT students before + + align:start position:0% +any advice to our MIT students before + + + align:start position:0% +any advice to our MIT students before +they take your good feedback and turn + + align:start position:0% +they take your good feedback and turn + + + align:start position:0% +they take your good feedback and turn +them into videos? Anything you want to + + align:start position:0% +them into videos? Anything you want to + + + align:start position:0% +them into videos? Anything you want to +make sure that they know to do or not to + + align:start position:0% +make sure that they know to do or not to + + + align:start position:0% +make sure that they know to do or not to +do as they take your good ideas and over + + align:start position:0% +do as they take your good ideas and over + + + align:start position:0% +do as they take your good ideas and over +the next month develop them into actual + + align:start position:0% +the next month develop them into actual + + + align:start position:0% +the next month develop them into actual +movies? + + align:start position:0% +movies? + + + align:start position:0% +movies? +use + + align:start position:0% +use + + + align:start position:0% +use +like picture ideas instead of talking to + + align:start position:0% +like picture ideas instead of talking to + + + align:start position:0% +like picture ideas instead of talking to +them like show examples so they can + + align:start position:0% +them like show examples so they can + + + align:start position:0% +them like show examples so they can +memorize it. That's what So we talked + + align:start position:0% +memorize it. That's what So we talked + + + align:start position:0% +memorize it. That's what So we talked +about that MIT students yesterday the + + align:start position:0% +about that MIT students yesterday the + + + align:start position:0% +about that MIT students yesterday the +idea of showing don't telling which I'm + + align:start position:0% +idea of showing don't telling which I'm + + + align:start position:0% +idea of showing don't telling which I'm +sure you guys talk about in your writing + + align:start position:0% +sure you guys talk about in your writing + + + align:start position:0% +sure you guys talk about in your writing +a lot right showing don't telling. Cool. + + align:start position:0% +a lot right showing don't telling. Cool. + + + align:start position:0% +a lot right showing don't telling. Cool. +Don't ask too many questions like cuz we + + align:start position:0% +Don't ask too many questions like cuz we + + + align:start position:0% +Don't ask too many questions like cuz we +watched one video and it asked a ton of + + align:start position:0% +watched one video and it asked a ton of + + + align:start position:0% +watched one video and it asked a ton of +questions and we didn't really + + align:start position:0% +questions and we didn't really + + + align:start position:0% +questions and we didn't really +understand it. Do you mean asking the + + align:start position:0% +understand it. Do you mean asking the + + + align:start position:0% +understand it. Do you mean asking the +audience questions? Like saying like + + align:start position:0% +audience questions? Like saying like + + + align:start position:0% +audience questions? Like saying like +what does this do? What does this do? It + + align:start position:0% +what does this do? What does this do? It + + + align:start position:0% +what does this do? What does this do? It +could just say one thing and then show + + align:start position:0% +could just say one thing and then show + + + align:start position:0% +could just say one thing and then show +it. So asking your audience too many + + align:start position:0% +it. So asking your audience too many + + + align:start position:0% +it. So asking your audience too many +questions is annoying. Yeah. + + align:start position:0% +questions is annoying. Yeah. + + + align:start position:0% +questions is annoying. Yeah. +You first and then you. The original. + + align:start position:0% +You first and then you. The original. + + + align:start position:0% +You first and then you. The original. +The original. So try to have a new idea. + + align:start position:0% +The original. So try to have a new idea. + + + align:start position:0% +The original. So try to have a new idea. +And what else? Um while you explain how + + align:start position:0% +And what else? Um while you explain how + + + align:start position:0% +And what else? Um while you explain how +things work, try and make some jokes + + align:start position:0% +things work, try and make some jokes + + + align:start position:0% +things work, try and make some jokes +while you do it so your audience laughs + + align:start position:0% +while you do it so your audience laughs + + + align:start position:0% +while you do it so your audience laughs +at it and like they understand what + + align:start position:0% +at it and like they understand what + + + align:start position:0% +at it and like they understand what +you're talking about. Awesome. Last one. + + align:start position:0% +you're talking about. Awesome. Last one. + + + align:start position:0% +you're talking about. Awesome. Last one. +Um, don't use like a monotonous pitch. + + align:start position:0% +Um, don't use like a monotonous pitch. + + + align:start position:0% +Um, don't use like a monotonous pitch. +Awesome. To change your voice around and + + align:start position:0% +Awesome. To change your voice around and + + + align:start position:0% +Awesome. To change your voice around and +make it more interesting. MIT students, + + align:start position:0% +make it more interesting. MIT students, + + + align:start position:0% +make it more interesting. MIT students, +I'm curious from you. What was valuable + + align:start position:0% +I'm curious from you. What was valuable + + + align:start position:0% +I'm curious from you. What was valuable +that you got from the sixth graders + + align:start position:0% +that you got from the sixth graders + + + align:start position:0% +that you got from the sixth graders +today to give them some feedback about + + align:start position:0% +today to give them some feedback about + + + align:start position:0% +today to give them some feedback about +this experience? Did anyone get some + + align:start position:0% +this experience? Did anyone get some + + + align:start position:0% +this experience? Did anyone get some +good feedback? Yeah. Uh, well, I found + + align:start position:0% +good feedback? Yeah. Uh, well, I found + + + align:start position:0% +good feedback? Yeah. Uh, well, I found +that um, and I should have realized this + + align:start position:0% +that um, and I should have realized this + + + align:start position:0% +that um, and I should have realized this +is that having robots stomping around + + align:start position:0% +is that having robots stomping around + + + align:start position:0% +is that having robots stomping around +and destroying cities is way more fun + + align:start position:0% +and destroying cities is way more fun + + + align:start position:0% +and destroying cities is way more fun +than showing old people doing math. + + align:start position:0% +than showing old people doing math. + + + align:start position:0% +than showing old people doing math. +Robots are more than old people doing + + align:start position:0% +Robots are more than old people doing + + + align:start position:0% +Robots are more than old people doing +math. H. + + align:start position:0% +math. H. + + + align:start position:0% +math. H. +Uh I too learned that my tastes are + + align:start position:0% +Uh I too learned that my tastes are + + + align:start position:0% +Uh I too learned that my tastes are +different. Uh that uh lava and volcanoes + + align:start position:0% +different. Uh that uh lava and volcanoes + + + align:start position:0% +different. Uh that uh lava and volcanoes +are a lot more interesting than food + + align:start position:0% +are a lot more interesting than food + + + align:start position:0% +are a lot more interesting than food +decomposing. + + align:start position:0% +decomposing. + + + align:start position:0% +decomposing. +He wanted to show food rotting and + + align:start position:0% +He wanted to show food rotting and + + + align:start position:0% +He wanted to show food rotting and +everyone thought that was not as fun as + + align:start position:0% +everyone thought that was not as fun as + + + align:start position:0% +everyone thought that was not as fun as +volcanoes exploding. Um any other thing + + align:start position:0% +volcanoes exploding. Um any other thing + + + align:start position:0% +volcanoes exploding. Um any other thing +from the MIT students that you found was + + align:start position:0% +from the MIT students that you found was + + + align:start position:0% +from the MIT students that you found was +helpful? Yeah, I was kind of like I + + align:start position:0% +helpful? Yeah, I was kind of like I + + + align:start position:0% +helpful? Yeah, I was kind of like I +don't know. It was humbling to know how + + align:start position:0% +don't know. It was humbling to know how + + + align:start position:0% +don't know. It was humbling to know how +much people like even sixth graders know + + align:start position:0% +much people like even sixth graders know + + + align:start position:0% +much people like even sixth graders know +about some of the really complicated + + align:start position:0% +about some of the really complicated + + + align:start position:0% +about some of the really complicated +subjects that we're even learning here. + + align:start position:0% +subjects that we're even learning here. + + + align:start position:0% +subjects that we're even learning here. +So awesome. A lot. We had some good + + align:start position:0% +So awesome. A lot. We had some good + + + align:start position:0% +So awesome. A lot. We had some good +conversation about sticking and floating + + align:start position:0% +conversation about sticking and floating + + + align:start position:0% +conversation about sticking and floating +and how do boats even work. It was + + align:start position:0% +and how do boats even work. It was + + + align:start position:0% +and how do boats even work. It was +awesome how much you guys do. Well, we + + align:start position:0% +awesome how much you guys do. Well, we + + + align:start position:0% +awesome how much you guys do. Well, we +can't thank you six readers enough for + + align:start position:0% +can't thank you six readers enough for + + + align:start position:0% +can't thank you six readers enough for +coming here today. It was so helpful. + + align:start position:0% +coming here today. It was so helpful. + + + align:start position:0% +coming here today. It was so helpful. +Thank + + align:start position:0% +Thank + + + align:start position:0% +Thank +[Applause] + + align:start position:0% +[Applause] + + + align:start position:0% +[Applause] +you. And I'm sure Elizabeth will be in + + align:start position:0% +you. And I'm sure Elizabeth will be in + + + align:start position:0% +you. And I'm sure Elizabeth will be in +touch with you guys to let you know how + + align:start position:0% +touch with you guys to let you know how + + + align:start position:0% +touch with you guys to let you know how +we our ideas and the videos that you + + align:start position:0% +we our ideas and the videos that you + + + align:start position:0% +we our ideas and the videos that you +guys made with me last month. They're + + align:start position:0% +guys made with me last month. They're + + + align:start position:0% +guys made with me last month. They're +almost finished. Carrie is almost + + align:start position:0% +almost finished. Carrie is almost + + + align:start position:0% +almost finished. Carrie is almost +finished with them today. So I will send + + align:start position:0% +finished with them today. So I will send + + + align:start position:0% +finished with them today. So I will send +those over to your teacher and you can + + align:start position:0% +those over to your teacher and you can + + + align:start position:0% +those over to your teacher and you can +watch them sometimes. + + align:start position:0% +watch them sometimes. + + + align:start position:0% +watch them sometimes. +Any directions from teachers before they + + align:start position:0% +Any directions from teachers before they + + + align:start position:0% +Any directions from teachers before they +leave the room on what's coming up next? + + align:start position:0% +leave the room on what's coming up next? + + + align:start position:0% +leave the room on what's coming up next? +Nope. Just um make one long single line + + align:start position:0% +Nope. Just um make one long single line + + + align:start position:0% +Nope. Just um make one long single line +so I can count you before you leave the + + align:start position:0% +so I can count you before you leave the + + + align:start position:0% +so I can count you before you leave the +building and then I'll count you on the + + align:start position:0% +building and then I'll count you on the + + + align:start position:0% +building and then I'll count you on the +bus again. check for jackets and all + + align:start position:0% +bus again. check for jackets and all + + + align:start position:0% +bus again. check for jackets and all +those things, but have a safe trip back + + align:start position:0% +those things, but have a safe trip back + + + align:start position:0% +those things, but have a safe trip back +home. Did you say thank you? Thank you. + + align:start position:0% +home. Did you say thank you? Thank you. + + + align:start position:0% +home. Did you say thank you? Thank you. +Thank you so much. \ No newline at end of file diff --git a/rWnyP-iZGu4.txt b/rWnyP-iZGu4.txt new file mode 100644 index 0000000000000000000000000000000000000000..6b9a185398280a8c0760c2a79802a8c3b3429790 --- /dev/null +++ b/rWnyP-iZGu4.txt @@ -0,0 +1,12187 @@ +align:start position:0% + +okay greetings everyone + + align:start position:0% +okay greetings everyone + + + align:start position:0% +okay greetings everyone +thank you for coming today + + align:start position:0% +thank you for coming today + + + align:start position:0% +thank you for coming today +i'll say a few things so in terms of the + + align:start position:0% +i'll say a few things so in terms of the + + + align:start position:0% +i'll say a few things so in terms of the +calendar + + align:start position:0% +calendar + + + align:start position:0% +calendar +and we're finishing off this section + + align:start position:0% +and we're finishing off this section + + + align:start position:0% +and we're finishing off this section +right before thanksgiving break when i + + align:start position:0% +right before thanksgiving break when i + + + align:start position:0% +right before thanksgiving break when i +get excuse me on identification today + + align:start position:0% +get excuse me on identification today + + + align:start position:0% +get excuse me on identification today +we're on that momentarily + + align:start position:0% +we're on that momentarily + + + align:start position:0% +we're on that momentarily +and we have two + + align:start position:0% +and we have two + + + align:start position:0% +and we have two +formal lectures after the break + + align:start position:0% +formal lectures after the break + + + align:start position:0% +formal lectures after the break +on tuesday thursday so that's the + + align:start position:0% +on tuesday thursday so that's the + + + align:start position:0% +on tuesday thursday so that's the +calendar + + align:start position:0% +calendar + + + align:start position:0% +calendar +then in terms of the readings today is + + align:start position:0% +then in terms of the readings today is + + + align:start position:0% +then in terms of the readings today is +kind of important to point out + + align:start position:0% +kind of important to point out + + + align:start position:0% +kind of important to point out +the section on identification and + + align:start position:0% +the section on identification and + + + align:start position:0% +the section on identification and +falsification we're about to do + + align:start position:0% +falsification we're about to do + + + align:start position:0% +falsification we're about to do +uh there are three starred readings and + + align:start position:0% +uh there are three starred readings and + + + align:start position:0% +uh there are three starred readings and +they all come from varian + + align:start position:0% +they all come from varian + + + align:start position:0% +they all come from varian +and they're all really really good in + + align:start position:0% +and they're all really really good in + + + align:start position:0% +and they're all really really good in +fact i had to abbreviate in spots in + + align:start position:0% +fact i had to abbreviate in spots in + + + align:start position:0% +fact i had to abbreviate in spots in +order to cover all the topics so we were + + align:start position:0% +order to cover all the topics so we were + + + align:start position:0% +order to cover all the topics so we were +drawing on this material in part and + + align:start position:0% +drawing on this material in part and + + + align:start position:0% +drawing on this material in part and +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +you you will find it useful + + align:start position:0% +you you will find it useful + + + align:start position:0% +you you will find it useful +again it's not the whole book it's just + + align:start position:0% +again it's not the whole book it's just + + + align:start position:0% +again it's not the whole book it's just +very in these sections 8.1 through 8.3 + + align:start position:0% +very in these sections 8.1 through 8.3 + + + align:start position:0% +very in these sections 8.1 through 8.3 +8.5 and 8.7 + + align:start position:0% +8.5 and 8.7 + + + align:start position:0% +8.5 and 8.7 +then + + align:start position:0% +then + + + align:start position:0% +then +from last time let's have a little bit + + align:start position:0% +from last time let's have a little bit + + + align:start position:0% +from last time let's have a little bit +of a discussion + + align:start position:0% +of a discussion + + + align:start position:0% +of a discussion +let's see + + align:start position:0% +let's see + + + align:start position:0% +let's see +daniel + + align:start position:0% +daniel + + + align:start position:0% +daniel +can you tell me as best you can + + align:start position:0% +can you tell me as best you can + + + align:start position:0% +can you tell me as best you can +what the definition of is the positive + + align:start position:0% +what the definition of is the positive + + + align:start position:0% +what the definition of is the positive +representative consumer and + + align:start position:0% +representative consumer and + + + align:start position:0% +representative consumer and +the normal + + align:start position:0% +the normal + + + align:start position:0% +the normal +normative representative consumer + + align:start position:0% +normative representative consumer + + + align:start position:0% +normative representative consumer +sort of explaining what they are + + align:start position:0% +sort of explaining what they are + + + align:start position:0% +sort of explaining what they are +intuitively so like the idea is you're + + align:start position:0% +intuitively so like the idea is you're + + + align:start position:0% +intuitively so like the idea is you're +trying to + + align:start position:0% +trying to + + + align:start position:0% +trying to +treat the entire economy as a single + + align:start position:0% +treat the entire economy as a single + + + align:start position:0% +treat the entire economy as a single +person + + align:start position:0% +person + + + align:start position:0% +person +so um a positive representative consumer + + align:start position:0% +so um a positive representative consumer + + + align:start position:0% +so um a positive representative consumer +is + + align:start position:0% +is + + + align:start position:0% +is +the um at any given like level of wealth + + align:start position:0% +the um at any given like level of wealth + + + align:start position:0% +the um at any given like level of wealth +and input the + + align:start position:0% +and input the + + + align:start position:0% +and input the +the way to maximize um utility + + align:start position:0% +the way to maximize um utility + + + align:start position:0% +the way to maximize um utility +is to + + align:start position:0% +is to + + + align:start position:0% +is to +um spend your + + align:start position:0% +um spend your + + + align:start position:0% +um spend your +your wealth the way that customer would + + align:start position:0% +your wealth the way that customer would + + + align:start position:0% +your wealth the way that customer would +and then um + + align:start position:0% +and then um + + + align:start position:0% +and then um +and then uh distribute that to the + + align:start position:0% +and then uh distribute that to the + + + align:start position:0% +and then uh distribute that to the +people like + + align:start position:0% +people like + + + align:start position:0% +people like +in some way uh + + align:start position:0% +in some way uh + + + align:start position:0% +in some way uh +we + + align:start position:0% +we + + + align:start position:0% +we +we don't really know which way from the + + align:start position:0% +we don't really know which way from the + + + align:start position:0% +we don't really know which way from the +consumer but like it'll just be like the + + align:start position:0% +consumer but like it'll just be like the + + + align:start position:0% +consumer but like it'll just be like the +best distribution and then the + + align:start position:0% +best distribution and then the + + + align:start position:0% +best distribution and then the +um normative is very similar except for + + align:start position:0% +um normative is very similar except for + + + align:start position:0% +um normative is very similar except for +instead of the + + align:start position:0% +instead of the + + + align:start position:0% +instead of the +utility maximizing it's the pareto + + align:start position:0% +utility maximizing it's the pareto + + + align:start position:0% +utility maximizing it's the pareto +optimal + + align:start position:0% +optimal + + + align:start position:0% +optimal +way to distribute the wealth + + align:start position:0% + + + + align:start position:0% + +yeah um + + align:start position:0% + + + + align:start position:0% + +i guess i would sharpen up a little bit + + align:start position:0% +i guess i would sharpen up a little bit + + + align:start position:0% +i guess i would sharpen up a little bit +the positive one the idea is to get the + + align:start position:0% +the positive one the idea is to get the + + + align:start position:0% +the positive one the idea is to get the +the excess demand curve for the economy + + align:start position:0% +the excess demand curve for the economy + + + align:start position:0% +the excess demand curve for the economy +as if it were coming from this + + align:start position:0% +as if it were coming from this + + + align:start position:0% +as if it were coming from this +representative consumer maximizing + + align:start position:0% +representative consumer maximizing + + + align:start position:0% +representative consumer maximizing +utilities subject to + + align:start position:0% +utilities subject to + + + align:start position:0% +utilities subject to +resource constraints and the and that + + align:start position:0% +resource constraints and the and that + + + align:start position:0% +resource constraints and the and that +can representative consumer has + + align:start position:0% +can representative consumer has + + + align:start position:0% +can representative consumer has +all the resource constraints in the + + align:start position:0% +all the resource constraints in the + + + align:start position:0% +all the resource constraints in the +entire economy in particular + + align:start position:0% +entire economy in particular + + + align:start position:0% +entire economy in particular +the budget just says don't spend more + + align:start position:0% +the budget just says don't spend more + + + align:start position:0% +the budget just says don't spend more +than the economy wide wealth + + align:start position:0% +than the economy wide wealth + + + align:start position:0% +than the economy wide wealth +and you kind of said that but + + align:start position:0% +and you kind of said that but + + + align:start position:0% +and you kind of said that but +maybe better for me to + + align:start position:0% +maybe better for me to + + + align:start position:0% +maybe better for me to +repeat it a little bit + + align:start position:0% +repeat it a little bit + + + align:start position:0% +repeat it a little bit +yeah and then the normative one is a way + + align:start position:0% +yeah and then the normative one is a way + + + align:start position:0% +yeah and then the normative one is a way +to rank order allocations + + align:start position:0% +to rank order allocations + + + align:start position:0% +to rank order allocations +according to the + + align:start position:0% +according to the + + + align:start position:0% +according to the +pareto principle but ironically rather + + align:start position:0% +pareto principle but ironically rather + + + align:start position:0% +pareto principle but ironically rather +than keeping track of all the + + align:start position:0% +than keeping track of all the + + + align:start position:0% +than keeping track of all the +individuals + + align:start position:0% +individuals + + + align:start position:0% +individuals +and whether they're made better off or + + align:start position:0% +and whether they're made better off or + + + align:start position:0% +and whether they're made better off or +worse off we can collapse it to + + align:start position:0% +worse off we can collapse it to + + + align:start position:0% +worse off we can collapse it to +as if we were maximizing utility for the + + align:start position:0% +as if we were maximizing utility for the + + + align:start position:0% +as if we were maximizing utility for the +whole economy + + align:start position:0% +whole economy + + + align:start position:0% +whole economy +through the lens of this representative + + align:start position:0% +through the lens of this representative + + + align:start position:0% +through the lens of this representative +consumer + + align:start position:0% +consumer + + + align:start position:0% +consumer +and as you said + + align:start position:0% +and as you said + + + align:start position:0% +and as you said +um + + align:start position:0% +um + + + align:start position:0% +um +that that kind of determines the overall + + align:start position:0% +that that kind of determines the overall + + + align:start position:0% +that that kind of determines the overall +allocation it doesn't + + align:start position:0% +allocation it doesn't + + + align:start position:0% +allocation it doesn't +pin down the + + align:start position:0% +pin down the + + + align:start position:0% +pin down the +potential reallocation of wealth + + align:start position:0% +potential reallocation of wealth + + + align:start position:0% +potential reallocation of wealth +that is uh necessary if you go from + + align:start position:0% +that is uh necessary if you go from + + + align:start position:0% +that is uh necessary if you go from +something pareto fury inferior to + + align:start position:0% +something pareto fury inferior to + + + align:start position:0% +something pareto fury inferior to +something + + align:start position:0% +something + + + align:start position:0% +something +credo superior or pareto optimal + + align:start position:0% +credo superior or pareto optimal + + + align:start position:0% +credo superior or pareto optimal +you may have to + + align:start position:0% +you may have to + + + align:start position:0% +you may have to +compensate + + align:start position:0% +compensate + + + align:start position:0% +compensate +the losers and + + align:start position:0% +the losers and + + + align:start position:0% +the losers and +by taxing the winners + + align:start position:0% +by taxing the winners + + + align:start position:0% +by taxing the winners +okay great + + align:start position:0% +okay great + + + align:start position:0% +okay great +um + + align:start position:0% + + + + align:start position:0% + +so we made a lot of use of this gorman + + align:start position:0% +so we made a lot of use of this gorman + + + align:start position:0% +so we made a lot of use of this gorman +form + + align:start position:0% +form + + + align:start position:0% +form +caleb can you tell me + + align:start position:0% +caleb can you tell me + + + align:start position:0% +caleb can you tell me +what in words what is this gorman + + align:start position:0% +what in words what is this gorman + + + align:start position:0% +what in words what is this gorman +polar form + + align:start position:0% + + + + align:start position:0% + +uh yeah so it + + align:start position:0% +uh yeah so it + + + align:start position:0% +uh yeah so it +it + + align:start position:0% +it + + + align:start position:0% +it +actually like it breaks down the uh + + align:start position:0% +actually like it breaks down the uh + + + align:start position:0% +actually like it breaks down the uh +the the like equilibrium into like a + + align:start position:0% +the the like equilibrium into like a + + + align:start position:0% +the the like equilibrium into like a +linear form i guess i don't know exactly + + align:start position:0% +linear form i guess i don't know exactly + + + align:start position:0% +linear form i guess i don't know exactly +how to explain it um + + align:start position:0% + + + + align:start position:0% + +uh + + align:start position:0% +uh + + + align:start position:0% +uh +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +do you remember any of the notation + + align:start position:0% + + + + align:start position:0% + +what is it breaking down exactly + + align:start position:0% +what is it breaking down exactly + + + align:start position:0% +what is it breaking down exactly +um like like the equilibrium in the + + align:start position:0% +um like like the equilibrium in the + + + align:start position:0% +um like like the equilibrium in the +economy + + align:start position:0% + + + + align:start position:0% + +does the word indirect utility come to + + align:start position:0% +does the word indirect utility come to + + + align:start position:0% +does the word indirect utility come to +mind + + align:start position:0% +mind + + + align:start position:0% +mind +um + + align:start position:0% + + + + align:start position:0% + +okay it's the + + align:start position:0% +okay it's the + + + align:start position:0% +okay it's the +it's the indirect utility function + + align:start position:0% +it's the indirect utility function + + + align:start position:0% +it's the indirect utility function +which is the maximized utility + + align:start position:0% +which is the maximized utility + + + align:start position:0% +which is the maximized utility +subject to the given vector of prices + + align:start position:0% +subject to the given vector of prices + + + align:start position:0% +subject to the given vector of prices +and wealth + + align:start position:0% + + + + align:start position:0% + +and + + align:start position:0% +and + + + align:start position:0% +and +the statement about gorman forum is this + + align:start position:0% +the statement about gorman forum is this + + + align:start position:0% +the statement about gorman forum is this +form in which + + align:start position:0% +form in which + + + align:start position:0% +form in which +uh that that + + align:start position:0% +uh that that + + + align:start position:0% +uh that that +indirect utility function must take + + align:start position:0% +indirect utility function must take + + + align:start position:0% +indirect utility function must take +in order to do this positive and + + align:start position:0% +in order to do this positive and + + + align:start position:0% +in order to do this positive and +normative thing just can someone + + align:start position:0% +normative thing just can someone + + + align:start position:0% +normative thing just can someone +volunteer to tell me what + + align:start position:0% +volunteer to tell me what + + + align:start position:0% +volunteer to tell me what +in words if you can what the gorman form + + align:start position:0% +in words if you can what the gorman form + + + align:start position:0% +in words if you can what the gorman form +looks like + + align:start position:0% +looks like + + + align:start position:0% +looks like +uh sure i can take this one + + align:start position:0% +uh sure i can take this one + + + align:start position:0% +uh sure i can take this one +great + + align:start position:0% +great + + + align:start position:0% +great +um so the garmin form is basically + + align:start position:0% +um so the garmin form is basically + + + align:start position:0% +um so the garmin form is basically +um an indirect utility function that is + + align:start position:0% +um an indirect utility function that is + + + align:start position:0% +um an indirect utility function that is +linear in w uh the overall like wealth + + align:start position:0% +linear in w uh the overall like wealth + + + align:start position:0% +linear in w uh the overall like wealth +of the economy so it's some function a + + align:start position:0% +of the economy so it's some function a + + + align:start position:0% +of the economy so it's some function a +which depends on prices plus some + + align:start position:0% +which depends on prices plus some + + + align:start position:0% +which depends on prices plus some +function b which depends on prices plus + + align:start position:0% +function b which depends on prices plus + + + align:start position:0% +function b which depends on prices plus +w + + align:start position:0% +w + + + align:start position:0% +w +yeah + + align:start position:0% +yeah + + + align:start position:0% +yeah +that's exactly right + + align:start position:0% +that's exactly right + + + align:start position:0% +that's exactly right +well it's at the level of the + + align:start position:0% +well it's at the level of the + + + align:start position:0% +well it's at the level of the +individuals + + align:start position:0% +individuals + + + align:start position:0% +individuals +um + + align:start position:0% +um + + + align:start position:0% +um +yes + + align:start position:0% +yes + + + align:start position:0% +yes +so + + align:start position:0% +so + + + align:start position:0% +so +if we had an individual i where do we + + align:start position:0% +if we had an individual i where do we + + + align:start position:0% +if we had an individual i where do we +put the i in that equation + + align:start position:0% +put the i in that equation + + + align:start position:0% +put the i in that equation +um so it is the + + align:start position:0% +um so it is the + + + align:start position:0% +um so it is the +um it is on both the wealth that an + + align:start position:0% +um it is on both the wealth that an + + + align:start position:0% +um it is on both the wealth that an +individual person faces and i think as + + align:start position:0% +individual person faces and i think as + + + align:start position:0% +individual person faces and i think as +well + + align:start position:0% +well + + + align:start position:0% +well +um + + align:start position:0% +um + + + align:start position:0% +um +on the functions a and b they can have + + align:start position:0% +on the functions a and b they can have + + + align:start position:0% +on the functions a and b they can have +each individual can have their own + + align:start position:0% +each individual can have their own + + + align:start position:0% +each individual can have their own +specific form for that + + align:start position:0% + + + + align:start position:0% + +two out of three so it's on the wealth + + align:start position:0% +two out of three so it's on the wealth + + + align:start position:0% +two out of three so it's on the wealth +because at the individual level it's the + + align:start position:0% +because at the individual level it's the + + + align:start position:0% +because at the individual level it's the +indirect utility is a function of the + + align:start position:0% +indirect utility is a function of the + + + align:start position:0% +indirect utility is a function of the +individual's wealth say w sub i + + align:start position:0% +individual's wealth say w sub i + + + align:start position:0% +individual's wealth say w sub i +the intercept term the a of p is the a i + + align:start position:0% +the intercept term the a of p is the a i + + + align:start position:0% +the intercept term the a of p is the a i +of p + + align:start position:0% +of p + + + align:start position:0% +of p +so that's where the heterogeneity is + + align:start position:0% +so that's where the heterogeneity is + + + align:start position:0% +so that's where the heterogeneity is +loaded + + align:start position:0% +loaded + + + align:start position:0% +loaded +um + + align:start position:0% +um + + + align:start position:0% +um +but it's not on the b and maybe + + align:start position:0% +but it's not on the b and maybe + + + align:start position:0% +but it's not on the b and maybe +you can remember y what did we say about + + align:start position:0% +you can remember y what did we say about + + + align:start position:0% +you can remember y what did we say about +those linear expansion paths oh those + + align:start position:0% +those linear expansion paths oh those + + + align:start position:0% +those linear expansion paths oh those +need to be parallel linear expansion + + align:start position:0% +need to be parallel linear expansion + + + align:start position:0% +need to be parallel linear expansion +paths and so they need to be identical + + align:start position:0% +paths and so they need to be identical + + + align:start position:0% +paths and so they need to be identical +for each consumer exactly so that's + + align:start position:0% +for each consumer exactly so that's + + + align:start position:0% +for each consumer exactly so that's +perfect so there's no i + + align:start position:0% +perfect so there's no i + + + align:start position:0% +perfect so there's no i +for the b part + + align:start position:0% +for the b part + + + align:start position:0% +for the b part +uh okay and then finally + + align:start position:0% +uh okay and then finally + + + align:start position:0% +uh okay and then finally +oh i + + align:start position:0% +oh i + + + align:start position:0% +oh i +almost + + align:start position:0% +almost + + + align:start position:0% +almost +answered this already + + align:start position:0% +answered this already + + + align:start position:0% +answered this already +but we can discuss it some more how + + align:start position:0% +but we can discuss it some more how + + + align:start position:0% +but we can discuss it some more how +realistic are the necessary and + + align:start position:0% +realistic are the necessary and + + + align:start position:0% +realistic are the necessary and +sufficient conditions + + align:start position:0% +sufficient conditions + + + align:start position:0% +sufficient conditions +for gorman aggregation based on what + + align:start position:0% +for gorman aggregation based on what + + + align:start position:0% +for gorman aggregation based on what +you've learned in previous lectures + + align:start position:0% + + + + align:start position:0% + +in other words do you believe it or not + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +yeah i think one i believe one of the + + align:start position:0% +yeah i think one i believe one of the + + + align:start position:0% +yeah i think one i believe one of the +necessary conditions was that like the + + align:start position:0% +necessary conditions was that like the + + + align:start position:0% +necessary conditions was that like the +the aggregate the aggregate demand + + align:start position:0% +the aggregate the aggregate demand + + + align:start position:0% +the aggregate the aggregate demand +doesn't depend on the sort of the + + align:start position:0% +doesn't depend on the sort of the + + + align:start position:0% +doesn't depend on the sort of the +distribution of the wealth it has to + + align:start position:0% +distribution of the wealth it has to + + + align:start position:0% +distribution of the wealth it has to +demand like only on the total wealth + + align:start position:0% +demand like only on the total wealth + + + align:start position:0% +demand like only on the total wealth +that's true and then what does that + + align:start position:0% +that's true and then what does that + + + align:start position:0% +that's true and then what does that +imply about the underlying + + align:start position:0% +imply about the underlying + + + align:start position:0% +imply about the underlying +households in the economy + + align:start position:0% +households in the economy + + + align:start position:0% +households in the economy +um + + align:start position:0% +um + + + align:start position:0% +um +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +i think i believe it i believe it i + + align:start position:0% +i think i believe it i believe it i + + + align:start position:0% +i think i believe it i believe it i +believe there's some sort of like + + align:start position:0% +believe there's some sort of like + + + align:start position:0% +believe there's some sort of like +implies some sort of like + + align:start position:0% + + + + align:start position:0% + +uniformity + + align:start position:0% +uniformity + + + align:start position:0% +uniformity +yeah it's uniform + + align:start position:0% +yeah it's uniform + + + align:start position:0% +yeah it's uniform +in the way that wealth + + align:start position:0% +in the way that wealth + + + align:start position:0% +in the way that wealth +impacts marginal changes + + align:start position:0% +impacts marginal changes + + + align:start position:0% +impacts marginal changes +right + + align:start position:0% +right + + + align:start position:0% +right +so + + align:start position:0% +so + + + align:start position:0% +so +yeah those linear expansion paths are a + + align:start position:0% +yeah those linear expansion paths are a + + + align:start position:0% +yeah those linear expansion paths are a +shorthand way of saying + + align:start position:0% +shorthand way of saying + + + align:start position:0% +shorthand way of saying +um + + align:start position:0% +um + + + align:start position:0% +um +different people can consume different + + align:start position:0% +different people can consume different + + + align:start position:0% +different people can consume different +amounts because they have different + + align:start position:0% +amounts because they have different + + + align:start position:0% +amounts because they have different +wealth + + align:start position:0% +wealth + + + align:start position:0% +wealth +but if you start changing wealth + + align:start position:0% +but if you start changing wealth + + + align:start position:0% +but if you start changing wealth +distribution by definition holding the + + align:start position:0% +distribution by definition holding the + + + align:start position:0% +distribution by definition holding the +aggregate fixed if you're going to + + align:start position:0% +aggregate fixed if you're going to + + + align:start position:0% +aggregate fixed if you're going to +change the distribution + + align:start position:0% +change the distribution + + + align:start position:0% +change the distribution +you're increasing wealth for some + + align:start position:0% +you're increasing wealth for some + + + align:start position:0% +you're increasing wealth for some +households and decreasing it for others + + align:start position:0% +households and decreasing it for others + + + align:start position:0% +households and decreasing it for others +and those marginal changes and not just + + align:start position:0% +and those marginal changes and not just + + + align:start position:0% +and those marginal changes and not just +local changes global changes these could + + align:start position:0% +local changes global changes these could + + + align:start position:0% +local changes global changes these could +be + + align:start position:0% +be + + + align:start position:0% +be +big redistributions + + align:start position:0% +big redistributions + + + align:start position:0% +big redistributions +sort of offset each other + + align:start position:0% + + + + align:start position:0% + +in the aggregate the amount that + + align:start position:0% +in the aggregate the amount that + + + align:start position:0% +in the aggregate the amount that +consumption of a given good is going + + align:start position:0% +consumption of a given good is going + + + align:start position:0% +consumption of a given good is going +down for the people who are taxed is + + align:start position:0% +down for the people who are taxed is + + + align:start position:0% +down for the people who are taxed is +exactly equal to + + align:start position:0% +exactly equal to + + + align:start position:0% +exactly equal to +the amount that + + align:start position:0% +the amount that + + + align:start position:0% +the amount that +consumption of that good is going up for + + align:start position:0% +consumption of that good is going up for + + + align:start position:0% +consumption of that good is going up for +the people who get the subsidies + + align:start position:0% + + + + align:start position:0% + +and that's why the redistribution + + align:start position:0% +and that's why the redistribution + + + align:start position:0% +and that's why the redistribution +doesn't matter for the aggregate that's + + align:start position:0% +doesn't matter for the aggregate that's + + + align:start position:0% +doesn't matter for the aggregate that's +why we can do this representative + + align:start position:0% +why we can do this representative + + + align:start position:0% +why we can do this representative +consumer thing + + align:start position:0% +consumer thing + + + align:start position:0% +consumer thing +to get the aggregates + + align:start position:0% +to get the aggregates + + + align:start position:0% +to get the aggregates +because only aggregate wealth matters + + align:start position:0% +because only aggregate wealth matters + + + align:start position:0% +because only aggregate wealth matters +for aggregate demand as you said + + align:start position:0% +for aggregate demand as you said + + + align:start position:0% +for aggregate demand as you said +however + + align:start position:0% +however + + + align:start position:0% +however +it matters a whole lot for the + + align:start position:0% +it matters a whole lot for the + + + align:start position:0% +it matters a whole lot for the +individuals i mean if you're paying + + align:start position:0% +individuals i mean if you're paying + + + align:start position:0% +individuals i mean if you're paying +taxes lump sum + + align:start position:0% +taxes lump sum + + + align:start position:0% +taxes lump sum +to the government for it to be + + align:start position:0% +to the government for it to be + + + align:start position:0% +to the government for it to be +redistributed you know you get hurt + + align:start position:0% +redistributed you know you get hurt + + + align:start position:0% +redistributed you know you get hurt +so it's not a welfare statement + + align:start position:0% + + + + align:start position:0% + +um + + align:start position:0% +um + + + align:start position:0% +um +and and i'll just repeat that's why + + align:start position:0% +and and i'll just repeat that's why + + + align:start position:0% +and and i'll just repeat that's why +depending on what we're doing with free + + align:start position:0% +depending on what we're doing with free + + + align:start position:0% +depending on what we're doing with free +trade or something else + + align:start position:0% +trade or something else + + + align:start position:0% +trade or something else +in principle we may be able to make + + align:start position:0% +in principle we may be able to make + + + align:start position:0% +in principle we may be able to make +everyone better off + + align:start position:0% +everyone better off + + + align:start position:0% +everyone better off +as we are told by + + align:start position:0% +as we are told by + + + align:start position:0% +as we are told by +situations where + + align:start position:0% +situations where + + + align:start position:0% +situations where +there is a representative indifference + + align:start position:0% +there is a representative indifference + + + align:start position:0% +there is a representative indifference +curve and we're using implicitly + + align:start position:0% +curve and we're using implicitly + + + align:start position:0% +curve and we're using implicitly +gorman's + + align:start position:0% +gorman's + + + align:start position:0% +gorman's +form + + align:start position:0% +form + + + align:start position:0% +form +for the indirect utilities but that + + align:start position:0% +for the indirect utilities but that + + + align:start position:0% +for the indirect utilities but that +doesn't mean everyone is actually better + + align:start position:0% +doesn't mean everyone is actually better + + + align:start position:0% +doesn't mean everyone is actually better +off + + align:start position:0% +off + + + align:start position:0% +off +without the intervention because the + + align:start position:0% +without the intervention because the + + + align:start position:0% +without the intervention because the +factor prices are moving and + + align:start position:0% +factor prices are moving and + + + align:start position:0% +factor prices are moving and +some people own more labor than capital + + align:start position:0% +some people own more labor than capital + + + align:start position:0% +some people own more labor than capital +and vice versa so we really do + + align:start position:0% +and vice versa so we really do + + + align:start position:0% +and vice versa so we really do +need to be actively redistributing + + align:start position:0% +need to be actively redistributing + + + align:start position:0% +need to be actively redistributing +wealth in order to reap the gains + + align:start position:0% +wealth in order to reap the gains + + + align:start position:0% +wealth in order to reap the gains +from uh + + align:start position:0% +from uh + + + align:start position:0% +from uh +for everyone to benefit from the gains + + align:start position:0% +for everyone to benefit from the gains + + + align:start position:0% +for everyone to benefit from the gains +to trade + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so so this lecture + + align:start position:0% +so so this lecture + + + align:start position:0% +so so this lecture +from 18 + + align:start position:0% +from 18 + + + align:start position:0% +from 18 +was about + + align:start position:0% + + + + align:start position:0% + +a tool namely gorman aggregation which + + align:start position:0% +a tool namely gorman aggregation which + + + align:start position:0% +a tool namely gorman aggregation which +you kind of + + align:start position:0% +you kind of + + + align:start position:0% +you kind of +saw in the form of the earlier lectures + + align:start position:0% +saw in the form of the earlier lectures + + + align:start position:0% +saw in the form of the earlier lectures +without me elaborating on it + + align:start position:0% +without me elaborating on it + + + align:start position:0% +without me elaborating on it +so this was an opportunity to do that + + align:start position:0% +so this was an opportunity to do that + + + align:start position:0% +so this was an opportunity to do that +but it does take underlying assumptions + + align:start position:0% +but it does take underlying assumptions + + + align:start position:0% +but it does take underlying assumptions +and + + align:start position:0% +and + + + align:start position:0% +and +in part the micro data seem to + + align:start position:0% +in part the micro data seem to + + + align:start position:0% +in part the micro data seem to +contradict + + align:start position:0% +contradict + + + align:start position:0% +contradict +yeah i didn't push you guys very hard + + align:start position:0% +yeah i didn't push you guys very hard + + + align:start position:0% +yeah i didn't push you guys very hard +but do you believe it or not you know + + align:start position:0% +but do you believe it or not you know + + + align:start position:0% +but do you believe it or not you know +then it's + + align:start position:0% +then it's + + + align:start position:0% +then it's +do we see these differential wealth + + align:start position:0% +do we see these differential wealth + + + align:start position:0% +do we see these differential wealth +effects in practice we have + + align:start position:0% +effects in practice we have + + + align:start position:0% +effects in practice we have +normal goods and you know + + align:start position:0% +normal goods and you know + + + align:start position:0% +normal goods and you know +necessary goods and so on and even + + align:start position:0% +necessary goods and so on and even + + + align:start position:0% +necessary goods and so on and even +giffen goods as i said so + + align:start position:0% + + + + align:start position:0% + +to know if it's a bad approximation we'd + + align:start position:0% +to know if it's a bad approximation we'd + + + align:start position:0% +to know if it's a bad approximation we'd +have to take a stand on the underlying + + align:start position:0% +have to take a stand on the underlying + + + align:start position:0% +have to take a stand on the underlying +non-gorman + + align:start position:0% +non-gorman + + + align:start position:0% +non-gorman +indirect utility functions and simulate + + align:start position:0% +indirect utility functions and simulate + + + align:start position:0% +indirect utility functions and simulate +the economy and see if it looks almost + + align:start position:0% +the economy and see if it looks almost + + + align:start position:0% +the economy and see if it looks almost +linear even though + + align:start position:0% +linear even though + + + align:start position:0% +linear even though +it's not in which case the + + align:start position:0% +it's not in which case the + + + align:start position:0% +it's not in which case the +redistribution might be small + + align:start position:0% +redistribution might be small + + + align:start position:0% +redistribution might be small +um + + align:start position:0% +um + + + align:start position:0% +um +sorry the + + align:start position:0% +sorry the + + + align:start position:0% +sorry the +i said that wrong the + + align:start position:0% +i said that wrong the + + + align:start position:0% +i said that wrong the +the uh literal form of gorman + + align:start position:0% +the uh literal form of gorman + + + align:start position:0% +the uh literal form of gorman +aggregation + + align:start position:0% +aggregation + + + align:start position:0% +aggregation +as an analytic technique might get us + + align:start position:0% +as an analytic technique might get us + + + align:start position:0% +as an analytic technique might get us +close to what we want as a benchmark + + align:start position:0% +close to what we want as a benchmark + + + align:start position:0% +close to what we want as a benchmark +and since it's so tractable it's very + + align:start position:0% +and since it's so tractable it's very + + + align:start position:0% +and since it's so tractable it's very +tempted to use it but then again for + + align:start position:0% +tempted to use it but then again for + + + align:start position:0% +tempted to use it but then again for +other utility functions we could be + + align:start position:0% +other utility functions we could be + + + align:start position:0% +other utility functions we could be +really really far off and be misleading + + align:start position:0% +really really far off and be misleading + + + align:start position:0% +really really far off and be misleading +policy makers + + align:start position:0% +policy makers + + + align:start position:0% +policy makers +hence the micro data + + align:start position:0% +hence the micro data + + + align:start position:0% +hence the micro data +or my pitch is if you're going to do + + align:start position:0% +or my pitch is if you're going to do + + + align:start position:0% +or my pitch is if you're going to do +macro policy you have to have micro data + + align:start position:0% +macro policy you have to have micro data + + + align:start position:0% +macro policy you have to have micro data +period + + align:start position:0% +period + + + align:start position:0% +period +but that's partly a belief that i've + + align:start position:0% +but that's partly a belief that i've + + + align:start position:0% +but that's partly a belief that i've +acquired over time it's a matter of + + align:start position:0% +acquired over time it's a matter of + + + align:start position:0% +acquired over time it's a matter of +of experience + + align:start position:0% +of experience + + + align:start position:0% +of experience +although it's not always true that's the + + align:start position:0% +although it's not always true that's the + + + align:start position:0% +although it's not always true that's the +approximations can be very helpful + + align:start position:0% +approximations can be very helpful + + + align:start position:0% +approximations can be very helpful +uh okay so + + align:start position:0% +uh okay so + + + align:start position:0% +uh okay so +this the lecture today is kind of the + + align:start position:0% +this the lecture today is kind of the + + + align:start position:0% +this the lecture today is kind of the +reverse of that instead of putting + + align:start position:0% +reverse of that instead of putting + + + align:start position:0% +reverse of that instead of putting +structure on indirect utility functions + + align:start position:0% +structure on indirect utility functions + + + align:start position:0% +structure on indirect utility functions +we're going to see + + align:start position:0% +we're going to see + + + align:start position:0% +we're going to see +if we can get by with almost no + + align:start position:0% +if we can get by with almost no + + + align:start position:0% +if we can get by with almost no +structure at all + + align:start position:0% +structure at all + + + align:start position:0% +structure at all +on preferences and still be able to make + + align:start position:0% +on preferences and still be able to make + + + align:start position:0% +on preferences and still be able to make +predictions which are + + align:start position:0% +predictions which are + + + align:start position:0% +predictions which are +testable or rejectable + + align:start position:0% +testable or rejectable + + + align:start position:0% +testable or rejectable +so this part this lecture is all about + + align:start position:0% +so this part this lecture is all about + + + align:start position:0% +so this part this lecture is all about +economic science i kind of featured the + + align:start position:0% +economic science i kind of featured the + + + align:start position:0% +economic science i kind of featured the +science of experiments in lecture one + + align:start position:0% +science of experiments in lecture one + + + align:start position:0% +science of experiments in lecture one +as a motivation for the class we went + + align:start position:0% +as a motivation for the class we went + + + align:start position:0% +as a motivation for the class we went +through coupons and + + align:start position:0% +through coupons and + + + align:start position:0% +through coupons and +lucas and josh and + + align:start position:0% +lucas and josh and + + + align:start position:0% +lucas and josh and +and maskin and so on so + + align:start position:0% +and maskin and so on so + + + align:start position:0% +and maskin and so on so +so this is very much the science of + + align:start position:0% +so this is very much the science of + + + align:start position:0% +so this is very much the science of +doing experiments and i'll tell you + + align:start position:0% +doing experiments and i'll tell you + + + align:start position:0% +doing experiments and i'll tell you +exactly what we're going to do with + + align:start position:0% +exactly what we're going to do with + + + align:start position:0% +exactly what we're going to do with +micro data depending on the amount of + + align:start position:0% +micro data depending on the amount of + + + align:start position:0% +micro data depending on the amount of +data available and also sort of macro + + align:start position:0% +data available and also sort of macro + + + align:start position:0% +data available and also sort of macro +data + + align:start position:0% +data + + + align:start position:0% +data +trying to put as little structure as + + align:start position:0% +trying to put as little structure as + + + align:start position:0% +trying to put as little structure as +possible + + align:start position:0% +possible + + + align:start position:0% +possible +and still get rejectable restrictions + + align:start position:0% +and still get rejectable restrictions + + + align:start position:0% +and still get rejectable restrictions +okay + + align:start position:0% +okay + + + align:start position:0% +okay +said that + + align:start position:0% +said that + + + align:start position:0% +said that +so we're going to go through consumer + + align:start position:0% +so we're going to go through consumer + + + align:start position:0% +so we're going to go through consumer +optimization again which is as always a + + align:start position:0% +optimization again which is as always a + + + align:start position:0% +optimization again which is as always a +bit of a review + + align:start position:0% +bit of a review + + + align:start position:0% +bit of a review +we're going to approach that as if we + + align:start position:0% +we're going to approach that as if we + + + align:start position:0% +we're going to approach that as if we +had an infinite amount of data + + align:start position:0% +had an infinite amount of data + + + align:start position:0% +had an infinite amount of data +and that will take us back to the + + align:start position:0% +and that will take us back to the + + + align:start position:0% +and that will take us back to the +slutsky matrix which you may have + + align:start position:0% +slutsky matrix which you may have + + + align:start position:0% +slutsky matrix which you may have +forgotten by now but i'll try to remind + + align:start position:0% +forgotten by now but i'll try to remind + + + align:start position:0% +forgotten by now but i'll try to remind +you + + align:start position:0% +you + + + align:start position:0% +you +that's with an infinite amount of data + + align:start position:0% +that's with an infinite amount of data + + + align:start position:0% +that's with an infinite amount of data +we get restrictions that we can reject + + align:start position:0% +we get restrictions that we can reject + + + align:start position:0% +we get restrictions that we can reject +consumer rationality in principle + + align:start position:0% +consumer rationality in principle + + + align:start position:0% +consumer rationality in principle +and then we'll do the same thing with + + align:start position:0% +and then we'll do the same thing with + + + align:start position:0% +and then we'll do the same thing with +finite data and still derive algorithms + + align:start position:0% +finite data and still derive algorithms + + + align:start position:0% +finite data and still derive algorithms +running on finite data sets that would + + align:start position:0% +running on finite data sets that would + + + align:start position:0% +running on finite data sets that would +allow us to + + align:start position:0% +allow us to + + + align:start position:0% +allow us to +not reject or alternatively reject the + + align:start position:0% +not reject or alternatively reject the + + + align:start position:0% +not reject or alternatively reject the +rationality of the household generating + + align:start position:0% +rationality of the household generating + + + align:start position:0% +rationality of the household generating +the data then we'll come back to lucas a + + align:start position:0% +the data then we'll come back to lucas a + + + align:start position:0% +the data then we'll come back to lucas a +bit and computational considerations + + align:start position:0% +bit and computational considerations + + + align:start position:0% +bit and computational considerations +which i think has been clear throughout + + align:start position:0% +which i think has been clear throughout + + + align:start position:0% +which i think has been clear throughout +the lectures that we visit from time to + + align:start position:0% +the lectures that we visit from time to + + + align:start position:0% +the lectures that we visit from time to +time + + align:start position:0% +time + + + align:start position:0% +time +and i have some dug up some really + + align:start position:0% +and i have some dug up some really + + + align:start position:0% +and i have some dug up some really +interesting computer science material to + + align:start position:0% +interesting computer science material to + + + align:start position:0% +interesting computer science material to +share with you about how hard or easy it + + align:start position:0% +share with you about how hard or easy it + + + align:start position:0% +share with you about how hard or easy it +is to solve certain problems and whether + + align:start position:0% +is to solve certain problems and whether + + + align:start position:0% +is to solve certain problems and whether +it matters be provocative + + align:start position:0% +it matters be provocative + + + align:start position:0% +it matters be provocative +and then we'll go to general equilibrium + + align:start position:0% +and then we'll go to general equilibrium + + + align:start position:0% +and then we'll go to general equilibrium +theory and kind of do the same thing all + + align:start position:0% +theory and kind of do the same thing all + + + align:start position:0% +theory and kind of do the same thing all +over again + + align:start position:0% +over again + + + align:start position:0% +over again +and that's going to again come back to + + align:start position:0% +and that's going to again come back to + + + align:start position:0% +and that's going to again come back to +this + + align:start position:0% +this + + + align:start position:0% +this +you need micro to do macro statement + + align:start position:0% +you need micro to do macro statement + + + align:start position:0% +you need micro to do macro statement +that i + + align:start position:0% +that i + + + align:start position:0% +that i +just mentioned + + align:start position:0% +just mentioned + + + align:start position:0% +just mentioned +okay + + align:start position:0% +okay + + + align:start position:0% +okay +to get in the content of it + + align:start position:0% +to get in the content of it + + + align:start position:0% +to get in the content of it +this slide appears to come out of + + align:start position:0% +this slide appears to come out of + + + align:start position:0% +this slide appears to come out of +nowhere + + align:start position:0% +nowhere + + + align:start position:0% +nowhere +uh it was actually + + align:start position:0% +uh it was actually + + + align:start position:0% +uh it was actually +almost part of the lecture we had on + + align:start position:0% +almost part of the lecture we had on + + + align:start position:0% +almost part of the lecture we had on +income and substitution effects and i'll + + align:start position:0% +income and substitution effects and i'll + + + align:start position:0% +income and substitution effects and i'll +remind you of that in a minute in + + align:start position:0% +remind you of that in a minute in + + + align:start position:0% +remind you of that in a minute in +particular + + align:start position:0% +particular + + + align:start position:0% +particular +it has to do with the hixion demand + + align:start position:0% +it has to do with the hixion demand + + + align:start position:0% +it has to do with the hixion demand +and the expenditure function well i'll + + align:start position:0% +and the expenditure function well i'll + + + align:start position:0% +and the expenditure function well i'll +remind you now + + align:start position:0% +remind you now + + + align:start position:0% +remind you now +we did utility maximization subject to + + align:start position:0% +we did utility maximization subject to + + + align:start position:0% +we did utility maximization subject to +the budget and we got the falrazian or + + align:start position:0% +the budget and we got the falrazian or + + + align:start position:0% +the budget and we got the falrazian or +marshallian demand we also decomposed + + align:start position:0% +marshallian demand we also decomposed + + + align:start position:0% +marshallian demand we also decomposed +that into income and substitution + + align:start position:0% +that into income and substitution + + + align:start position:0% +that into income and substitution +effects and the way we got the + + align:start position:0% +effects and the way we got the + + + align:start position:0% +effects and the way we got the +substitution effects was to do + + align:start position:0% +substitution effects was to do + + + align:start position:0% +substitution effects was to do +compensation prices say if they decrease + + align:start position:0% +compensation prices say if they decrease + + + align:start position:0% +compensation prices say if they decrease +or associated with increases in income + + align:start position:0% +or associated with increases in income + + + align:start position:0% +or associated with increases in income +we take the income effects away and just + + align:start position:0% +we take the income effects away and just + + + align:start position:0% +we take the income effects away and just +look at how demands change as we change + + align:start position:0% +look at how demands change as we change + + + align:start position:0% +look at how demands change as we change +prices in other words we + + align:start position:0% +prices in other words we + + + align:start position:0% +prices in other words we +minimize the expenditure necessary to + + align:start position:0% +minimize the expenditure necessary to + + + align:start position:0% +minimize the expenditure necessary to +achieve a certain level of utility and + + align:start position:0% +achieve a certain level of utility and + + + align:start position:0% +achieve a certain level of utility and +we got the hicksian demand + + align:start position:0% +we got the hicksian demand + + + align:start position:0% +we got the hicksian demand +so with the hicks in demand and the + + align:start position:0% +so with the hicks in demand and the + + + align:start position:0% +so with the hicks in demand and the +expenditure function i checked we didn't + + align:start position:0% +expenditure function i checked we didn't + + + align:start position:0% +expenditure function i checked we didn't +actually go through these properties in + + align:start position:0% +actually go through these properties in + + + align:start position:0% +actually go through these properties in +lecture three but they are + + align:start position:0% +lecture three but they are + + + align:start position:0% +lecture three but they are +intuitive + + align:start position:0% +intuitive + + + align:start position:0% +intuitive +if the utility function is continuous + + align:start position:0% +if the utility function is continuous + + + align:start position:0% +if the utility function is continuous +represents locally non-satiated + + align:start position:0% +represents locally non-satiated + + + align:start position:0% +represents locally non-satiated +preferences we might as well define the + + align:start position:0% +preferences we might as well define the + + + align:start position:0% +preferences we might as well define the +consumption set to be the non-negative l + + align:start position:0% +consumption set to be the non-negative l + + + align:start position:0% +consumption set to be the non-negative l +dimensional orthot then we have the + + align:start position:0% +dimensional orthot then we have the + + + align:start position:0% +dimensional orthot then we have the +following four properties + + align:start position:0% +following four properties + + + align:start position:0% +following four properties +the + + align:start position:0% +the + + + align:start position:0% +the +expenditure function this minimized + + align:start position:0% +expenditure function this minimized + + + align:start position:0% +expenditure function this minimized +expenditure at prices p to achieve a + + align:start position:0% +expenditure at prices p to achieve a + + + align:start position:0% +expenditure at prices p to achieve a +certain utility level u is homogeneous + + align:start position:0% +certain utility level u is homogeneous + + + align:start position:0% +certain utility level u is homogeneous +of degree what + + align:start position:0% +of degree what + + + align:start position:0% +of degree what +one in + + align:start position:0% +one in + + + align:start position:0% +one in +those prices p + + align:start position:0% +those prices p + + + align:start position:0% +those prices p +i think i slipped up the other day when + + align:start position:0% +i think i slipped up the other day when + + + align:start position:0% +i think i slipped up the other day when +i said zero and then i switched back to + + align:start position:0% +i said zero and then i switched back to + + + align:start position:0% +i said zero and then i switched back to +one it depends on what object + + align:start position:0% +one it depends on what object + + + align:start position:0% +one it depends on what object +when we do utility maximization to + + align:start position:0% +when we do utility maximization to + + + align:start position:0% +when we do utility maximization to +budgets if we increase income and prices + + align:start position:0% +budgets if we increase income and prices + + + align:start position:0% +budgets if we increase income and prices +things are homogeneous of degrees zero + + align:start position:0% +things are homogeneous of degrees zero + + + align:start position:0% +things are homogeneous of degrees zero +because nothing changes + + align:start position:0% +because nothing changes + + + align:start position:0% +because nothing changes +but this is a property of the + + align:start position:0% +but this is a property of the + + + align:start position:0% +but this is a property of the +expenditure function so logically if + + align:start position:0% +expenditure function so logically if + + + align:start position:0% +expenditure function so logically if +prices go up and you're hitting the same + + align:start position:0% +prices go up and you're hitting the same + + + align:start position:0% +prices go up and you're hitting the same +level of utility it's going to cost you + + align:start position:0% +level of utility it's going to cost you + + + align:start position:0% +level of utility it's going to cost you +more so the expenditures just double if + + align:start position:0% +more so the expenditures just double if + + + align:start position:0% +more so the expenditures just double if +you're doubling prices + + align:start position:0% +you're doubling prices + + + align:start position:0% +you're doubling prices +it's homogeneous of degree one + + align:start position:0% +it's homogeneous of degree one + + + align:start position:0% +it's homogeneous of degree one +expenditure function + + align:start position:0% +expenditure function + + + align:start position:0% +expenditure function +for any given price vector p + + align:start position:0% +for any given price vector p + + + align:start position:0% +for any given price vector p +is increasing in utility that kind of + + align:start position:0% +is increasing in utility that kind of + + + align:start position:0% +is increasing in utility that kind of +makes sense when you think about having + + align:start position:0% +makes sense when you think about having + + + align:start position:0% +makes sense when you think about having +nice concave indifference curves or even + + align:start position:0% +nice concave indifference curves or even + + + align:start position:0% +nice concave indifference curves or even +linear indifference curves if you do + + align:start position:0% +linear indifference curves if you do + + + align:start position:0% +linear indifference curves if you do +increase u by moving further and further + + align:start position:0% +increase u by moving further and further + + + align:start position:0% +increase u by moving further and further +north out hitting higher and higher + + align:start position:0% +north out hitting higher and higher + + + align:start position:0% +north out hitting higher and higher +indifference curves than to minimize the + + align:start position:0% +indifference curves than to minimize the + + + align:start position:0% +indifference curves than to minimize the +expenditure of achieving those points + + align:start position:0% +expenditure of achieving those points + + + align:start position:0% +expenditure of achieving those points +the expenditure + + align:start position:0% +the expenditure + + + align:start position:0% +the expenditure +has to go up likewise as prices go up + + align:start position:0% +has to go up likewise as prices go up + + + align:start position:0% +has to go up likewise as prices go up +expenditures go up which i kind of + + align:start position:0% +expenditures go up which i kind of + + + align:start position:0% +expenditures go up which i kind of +already said + + align:start position:0% +already said + + + align:start position:0% +already said +and this is a key property + + align:start position:0% +and this is a key property + + + align:start position:0% +and this is a key property +in addition the expenditure function is + + align:start position:0% +in addition the expenditure function is + + + align:start position:0% +in addition the expenditure function is +concave in the prices so + + align:start position:0% +concave in the prices so + + + align:start position:0% +concave in the prices so +we're given that the utility function + + align:start position:0% +we're given that the utility function + + + align:start position:0% +we're given that the utility function +represents local non-satiated + + align:start position:0% +represents local non-satiated + + + align:start position:0% +represents local non-satiated +preferences we're not given much else so + + align:start position:0% +preferences we're not given much else so + + + align:start position:0% +preferences we're not given much else so +this this might be a bit surprising this + + align:start position:0% +this this might be a bit surprising this + + + align:start position:0% +this this might be a bit surprising this +allows for it to be linear however and + + align:start position:0% +allows for it to be linear however and + + + align:start position:0% +allows for it to be linear however and +in a minute we'll make it strictly + + align:start position:0% +in a minute we'll make it strictly + + + align:start position:0% +in a minute we'll make it strictly +concave + + align:start position:0% +concave + + + align:start position:0% +concave +anyway you remember how these proofs go + + align:start position:0% +anyway you remember how these proofs go + + + align:start position:0% +anyway you remember how these proofs go +pick two prices take pick a linear + + align:start position:0% +pick two prices take pick a linear + + + align:start position:0% +pick two prices take pick a linear +combination kind of prove that that + + align:start position:0% +combination kind of prove that that + + + align:start position:0% +combination kind of prove that that +intermediate combination is also + + align:start position:0% +intermediate combination is also + + + align:start position:0% +intermediate combination is also +minimizing expenditure etc + + align:start position:0% +minimizing expenditure etc + + + align:start position:0% +minimizing expenditure etc +and then the utility expenditure + + align:start position:0% +and then the utility expenditure + + + align:start position:0% +and then the utility expenditure +function is continuous in both objects + + align:start position:0% +function is continuous in both objects + + + align:start position:0% +function is continuous in both objects +the one i want to focus on is number + + align:start position:0% +the one i want to focus on is number + + + align:start position:0% +the one i want to focus on is number +three that the expenditure function is + + align:start position:0% +three that the expenditure function is + + + align:start position:0% +three that the expenditure function is +concave in prices for fixed utility + + align:start position:0% +concave in prices for fixed utility + + + align:start position:0% +concave in prices for fixed utility +okay relatedly + + align:start position:0% +okay relatedly + + + align:start position:0% +okay relatedly +the hixing demand + + align:start position:0% +the hixing demand + + + align:start position:0% +the hixing demand +is + + align:start position:0% +is + + + align:start position:0% +is +if you're going to achieve a target + + align:start position:0% +if you're going to achieve a target + + + align:start position:0% +if you're going to achieve a target +utility u + + align:start position:0% +utility u + + + align:start position:0% +utility u +then + + align:start position:0% +then + + + align:start position:0% +then +you will achieve it exactly essentially + + align:start position:0% +you will achieve it exactly essentially + + + align:start position:0% +you will achieve it exactly essentially +that is to say the x's which are part of + + align:start position:0% +that is to say the x's which are part of + + + align:start position:0% +that is to say the x's which are part of +the solution to the minimizing + + align:start position:0% +the solution to the minimizing + + + align:start position:0% +the solution to the minimizing +expenditure problem when substituted + + align:start position:0% +expenditure problem when substituted + + + align:start position:0% +expenditure problem when substituted +into the utility function generate u + + align:start position:0% +into the utility function generate u + + + align:start position:0% +into the utility function generate u +exactly if preferences are number two + + align:start position:0% +exactly if preferences are number two + + + align:start position:0% +exactly if preferences are number two +convex then these minimize expension + + align:start position:0% +convex then these minimize expension + + + align:start position:0% +convex then these minimize expension +demands are convex valued entertaining + + align:start position:0% +demands are convex valued entertaining + + + align:start position:0% +demands are convex valued entertaining +multiple solutions + + align:start position:0% +multiple solutions + + + align:start position:0% +multiple solutions +that minimize expenditure for given p + + align:start position:0% +that minimize expenditure for given p + + + align:start position:0% +that minimize expenditure for given p +and u + + align:start position:0% +and u + + + align:start position:0% +and u +but if preferences are strictly convex + + align:start position:0% +but if preferences are strictly convex + + + align:start position:0% +but if preferences are strictly convex +then + + align:start position:0% +then + + + align:start position:0% +then +this h function is single valued and + + align:start position:0% +this h function is single valued and + + + align:start position:0% +this h function is single valued and +continuous so here is where the strict + + align:start position:0% +continuous so here is where the strict + + + align:start position:0% +continuous so here is where the strict +convexity of the preferences comes in + + align:start position:0% +convexity of the preferences comes in + + + align:start position:0% +convexity of the preferences comes in +okay which we're going to get again to + + align:start position:0% +okay which we're going to get again to + + + align:start position:0% +okay which we're going to get again to +in four + + align:start position:0% +in four + + + align:start position:0% +in four +three says this pixie and demand is + + align:start position:0% +three says this pixie and demand is + + + align:start position:0% +three says this pixie and demand is +single value if it's single valued which + + align:start position:0% +single value if it's single valued which + + + align:start position:0% +single value if it's single valued which +it would be with strictly convex + + align:start position:0% +it would be with strictly convex + + + align:start position:0% +it would be with strictly convex +preferences then it's differentiable and + + align:start position:0% +preferences then it's differentiable and + + + align:start position:0% +preferences then it's differentiable and +moreover when you take the derivative of + + align:start position:0% +moreover when you take the derivative of + + + align:start position:0% +moreover when you take the derivative of +it with respect to say a price p sub l + + align:start position:0% +it with respect to say a price p sub l + + + align:start position:0% +it with respect to say a price p sub l +for the health good you get the + + align:start position:0% +for the health good you get the + + + align:start position:0% +for the health good you get the +minimize you get the quantities back + + align:start position:0% +minimize you get the quantities back + + + align:start position:0% +minimize you get the quantities back +so + + align:start position:0% +so + + + align:start position:0% +so +the intuition for this is + + align:start position:0% +the intuition for this is + + + align:start position:0% +the intuition for this is +expenditure is just p1 x1 p2 x2 dot dot + + align:start position:0% +expenditure is just p1 x1 p2 x2 dot dot + + + align:start position:0% +expenditure is just p1 x1 p2 x2 dot dot +pl xl uh you take the derivative with + + align:start position:0% +pl xl uh you take the derivative with + + + align:start position:0% +pl xl uh you take the derivative with +respect to p you're going to get the x + + align:start position:0% +respect to p you're going to get the x + + + align:start position:0% +respect to p you're going to get the x +that's a bit sloppy and we did the + + align:start position:0% +that's a bit sloppy and we did the + + + align:start position:0% +that's a bit sloppy and we did the +envelope theorem earlier and reviewed it + + align:start position:0% +envelope theorem earlier and reviewed it + + + align:start position:0% +envelope theorem earlier and reviewed it +last time but basically the derivative + + align:start position:0% +last time but basically the derivative + + + align:start position:0% +last time but basically the derivative +at the optimizing minimize expenditures + + align:start position:0% +at the optimizing minimize expenditures + + + align:start position:0% +at the optimizing minimize expenditures +at parametric price p sub l is + + align:start position:0% +at parametric price p sub l is + + + align:start position:0% +at parametric price p sub l is +you get the solution back the uh + + align:start position:0% +you get the solution back the uh + + + align:start position:0% +you get the solution back the uh +hixing demand + + align:start position:0% +hixing demand + + + align:start position:0% +hixing demand +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so these two pieces + + align:start position:0% +so these two pieces + + + align:start position:0% +so these two pieces +three and + + align:start position:0% +three and + + + align:start position:0% +three and +three + + align:start position:0% +three + + + align:start position:0% +three +on each of the two slides + + align:start position:0% +on each of the two slides + + + align:start position:0% +on each of the two slides +generate this statement that if you take + + align:start position:0% +generate this statement that if you take + + + align:start position:0% +generate this statement that if you take +the hixing demands and differentiate + + align:start position:0% +the hixing demands and differentiate + + + align:start position:0% +the hixing demands and differentiate +with respect to prices then because + + align:start position:0% +with respect to prices then because + + + align:start position:0% +with respect to prices then because +level h is on the right hand side in + + align:start position:0% +level h is on the right hand side in + + + align:start position:0% +level h is on the right hand side in +eight but the derivative is already on + + align:start position:0% +eight but the derivative is already on + + + align:start position:0% +eight but the derivative is already on +the left hand side so if you're + + align:start position:0% +the left hand side so if you're + + + align:start position:0% +the left hand side so if you're +differentiating the right all over again + + align:start position:0% +differentiating the right all over again + + + align:start position:0% +differentiating the right all over again +with respect to p you're double + + align:start position:0% +with respect to p you're double + + + align:start position:0% +with respect to p you're double +differentiating so to speak the left + + align:start position:0% +differentiating so to speak the left + + + align:start position:0% +differentiating so to speak the left +hand side so we get these second order + + align:start position:0% +hand side so we get these second order + + + align:start position:0% +hand side so we get these second order +partial derivatives bone and cross + + align:start position:0% +partial derivatives bone and cross + + + align:start position:0% +partial derivatives bone and cross +partial derivatives of the expenditure + + align:start position:0% +partial derivatives of the expenditure + + + align:start position:0% +partial derivatives of the expenditure +function when we differentiate the + + align:start position:0% +function when we differentiate the + + + align:start position:0% +function when we differentiate the +hixing demands + + align:start position:0% +hixing demands + + + align:start position:0% +hixing demands +this is really compact notation + + align:start position:0% +this is really compact notation + + + align:start position:0% +this is really compact notation +obviously there's a whole vector of + + align:start position:0% +obviously there's a whole vector of + + + align:start position:0% +obviously there's a whole vector of +prices p1 through pl + + align:start position:0% +prices p1 through pl + + + align:start position:0% +prices p1 through pl +etc or writing it down almost as if it + + align:start position:0% +etc or writing it down almost as if it + + + align:start position:0% +etc or writing it down almost as if it +were single dimension but it's meant to + + align:start position:0% +were single dimension but it's meant to + + + align:start position:0% +were single dimension but it's meant to +capture the entire l by l matrix that is + + align:start position:0% +capture the entire l by l matrix that is + + + align:start position:0% +capture the entire l by l matrix that is +to say the derivative of the first + + align:start position:0% +to say the derivative of the first + + + align:start position:0% +to say the derivative of the first +fixing demand with respect to the first + + align:start position:0% +fixing demand with respect to the first + + + align:start position:0% +fixing demand with respect to the first +price the first 60 in demand could with + + align:start position:0% +price the first 60 in demand could with + + + align:start position:0% +price the first 60 in demand could with +respect to the second price and so on + + align:start position:0% +respect to the second price and so on + + + align:start position:0% +respect to the second price and so on +going across the row + + align:start position:0% +going across the row + + + align:start position:0% +going across the row +fill out all the rows so it has all the + + align:start position:0% +fill out all the rows so it has all the + + + align:start position:0% +fill out all the rows so it has all the +own + + align:start position:0% +own + + + align:start position:0% +own +ii h i p i derivatives as well as h i j + + align:start position:0% +ii h i p i derivatives as well as h i j + + + align:start position:0% +ii h i p i derivatives as well as h i j +i good was with respect to the chafe + + align:start position:0% +i good was with respect to the chafe + + + align:start position:0% +i good was with respect to the chafe +price it's all loaded into this compact + + align:start position:0% +price it's all loaded into this compact + + + align:start position:0% +price it's all loaded into this compact +notation + + align:start position:0% +notation + + + align:start position:0% +notation +now i'm saving the best for last which + + align:start position:0% +now i'm saving the best for last which + + + align:start position:0% +now i'm saving the best for last which +is this guy here is the matrix of second + + align:start position:0% +is this guy here is the matrix of second + + + align:start position:0% +is this guy here is the matrix of second +order derivatives of the expenditure + + align:start position:0% +order derivatives of the expenditure + + + align:start position:0% +order derivatives of the expenditure +function and three + + align:start position:0% +function and three + + + align:start position:0% +function and three +already told us the expenditure function + + align:start position:0% +already told us the expenditure function + + + align:start position:0% +already told us the expenditure function +is concave + + align:start position:0% +is concave + + + align:start position:0% +is concave +so that means you know if you think + + align:start position:0% +so that means you know if you think + + + align:start position:0% +so that means you know if you think +about first order conditions and second + + align:start position:0% +about first order conditions and second + + + align:start position:0% +about first order conditions and second +order conditions that second order + + align:start position:0% +order conditions that second order + + + align:start position:0% +order conditions that second order +conditions are going to be satisfied + + align:start position:0% +conditions are going to be satisfied + + + align:start position:0% +conditions are going to be satisfied +for a concave function and in fact if + + align:start position:0% +for a concave function and in fact if + + + align:start position:0% +for a concave function and in fact if +you look it up stuff does slip memory a + + align:start position:0% +you look it up stuff does slip memory a + + + align:start position:0% +you look it up stuff does slip memory a +bit + + align:start position:0% +bit + + + align:start position:0% +bit +it means that this matrix of own and + + align:start position:0% +it means that this matrix of own and + + + align:start position:0% +it means that this matrix of own and +cross partial derivatives is symmetric + + align:start position:0% +cross partial derivatives is symmetric + + + align:start position:0% +cross partial derivatives is symmetric +and negative semi-definite + + align:start position:0% +and negative semi-definite + + + align:start position:0% +and negative semi-definite +you you may not remember that + + align:start position:0% +you you may not remember that + + + align:start position:0% +you you may not remember that +you think about one good then you just + + align:start position:0% +you think about one good then you just + + + align:start position:0% +you think about one good then you just +have first the ii derivative you think + + align:start position:0% +have first the ii derivative you think + + + align:start position:0% +have first the ii derivative you think +about 2 then you're going to have a + + align:start position:0% +about 2 then you're going to have a + + + align:start position:0% +about 2 then you're going to have a +2 by 2 matrix and you have the + + align:start position:0% +2 by 2 matrix and you have the + + + align:start position:0% +2 by 2 matrix and you have the +determinant of that matrix if you have + + align:start position:0% +determinant of that matrix if you have + + + align:start position:0% +determinant of that matrix if you have +three goods and it's a bit tricky you + + align:start position:0% +three goods and it's a bit tricky you + + + align:start position:0% +three goods and it's a bit tricky you +have to to factor the matrix you got to + + align:start position:0% +have to to factor the matrix you got to + + + align:start position:0% +have to to factor the matrix you got to +figure out the determinant of each of + + align:start position:0% +figure out the determinant of each of + + + align:start position:0% +figure out the determinant of each of +the sub components and so on but + + align:start position:0% +the sub components and so on but + + + align:start position:0% +the sub components and so on but +an equivalent way to check and see + + align:start position:0% +an equivalent way to check and see + + + align:start position:0% +an equivalent way to check and see +whether all the conditions are satisfied + + align:start position:0% +whether all the conditions are satisfied + + + align:start position:0% +whether all the conditions are satisfied +for concavity is just to pre-multiply + + align:start position:0% +for concavity is just to pre-multiply + + + align:start position:0% +for concavity is just to pre-multiply +and post multiply the matrix + + align:start position:0% +and post multiply the matrix + + + align:start position:0% +and post multiply the matrix +by + + align:start position:0% +by + + + align:start position:0% +by +a prime and a as + + align:start position:0% +a prime and a as + + + align:start position:0% +a prime and a as +as arbitrary vectors and make sure the + + align:start position:0% +as arbitrary vectors and make sure the + + + align:start position:0% +as arbitrary vectors and make sure the +result is + + align:start position:0% +result is + + + align:start position:0% +result is +negative + + align:start position:0% +negative + + + align:start position:0% +negative +so that's a little bit of a review don't + + align:start position:0% +so that's a little bit of a review don't + + + align:start position:0% +so that's a little bit of a review don't +worry about it if you never learned it + + align:start position:0% +worry about it if you never learned it + + + align:start position:0% +worry about it if you never learned it +it's the same thing as getting + + align:start position:0% +it's the same thing as getting + + + align:start position:0% +it's the same thing as getting +concavity of the + + align:start position:0% +concavity of the + + + align:start position:0% +concavity of the +expenditure function + + align:start position:0% +expenditure function + + + align:start position:0% +expenditure function +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so what + + align:start position:0% +so what + + + align:start position:0% +so what +okay + + align:start position:0% +okay + + + align:start position:0% +okay +well it's a bit problematic + + align:start position:0% +well it's a bit problematic + + + align:start position:0% +well it's a bit problematic +i said the motive today was to get + + align:start position:0% +i said the motive today was to get + + + align:start position:0% +i said the motive today was to get +restrictions on observables but we don't + + align:start position:0% +restrictions on observables but we don't + + + align:start position:0% +restrictions on observables but we don't +see this guy we don't see the hixing + + align:start position:0% +see this guy we don't see the hixing + + + align:start position:0% +see this guy we don't see the hixing +demand + + align:start position:0% +demand + + + align:start position:0% +demand +we just see the marshallian demand so + + align:start position:0% +we just see the marshallian demand so + + + align:start position:0% +we just see the marshallian demand so +we're kind of in trouble + + align:start position:0% +we're kind of in trouble + + + align:start position:0% +we're kind of in trouble +except + + align:start position:0% +except + + + align:start position:0% +except +this + + align:start position:0% +this + + + align:start position:0% +this +this is a statement about the slutsky + + align:start position:0% +this is a statement about the slutsky + + + align:start position:0% +this is a statement about the slutsky +matrix what we want to find which is the + + align:start position:0% +matrix what we want to find which is the + + + align:start position:0% +matrix what we want to find which is the +derivative of that thing we just looked + + align:start position:0% +derivative of that thing we just looked + + + align:start position:0% +derivative of that thing we just looked +at turns out it is associated with + + align:start position:0% +at turns out it is associated with + + + align:start position:0% +at turns out it is associated with +observables this is the elf good + + align:start position:0% +observables this is the elf good + + + align:start position:0% +observables this is the elf good +changing with respect to the k price is + + align:start position:0% +changing with respect to the k price is + + + align:start position:0% +changing with respect to the k price is +equal to the way the whole demand is + + align:start position:0% +equal to the way the whole demand is + + + align:start position:0% +equal to the way the whole demand is +changing of the health good as we change + + align:start position:0% +changing of the health good as we change + + + align:start position:0% +changing of the health good as we change +the price p k but we adjust for the + + align:start position:0% +the price p k but we adjust for the + + + align:start position:0% +the price p k but we adjust for the +income effect which is how the health + + align:start position:0% +income effect which is how the health + + + align:start position:0% +income effect which is how the health +grid is changing as we change income or + + align:start position:0% +grid is changing as we change income or + + + align:start position:0% +grid is changing as we change income or +wealth post multiplied by the quantity + + align:start position:0% +wealth post multiplied by the quantity + + + align:start position:0% +wealth post multiplied by the quantity +of the good price of which is changing + + align:start position:0% +of the good price of which is changing + + + align:start position:0% +of the good price of which is changing +namely pxk for pk okay + + align:start position:0% +namely pxk for pk okay + + + align:start position:0% +namely pxk for pk okay +so + + align:start position:0% +so + + + align:start position:0% +so +and you're probably still struggling i + + align:start position:0% +and you're probably still struggling i + + + align:start position:0% +and you're probably still struggling i +went back to check + + align:start position:0% +went back to check + + + align:start position:0% +went back to check +you may remember this remember these + + align:start position:0% +you may remember this remember these + + + align:start position:0% +you may remember this remember these +this lecture where we did the income and + + align:start position:0% +this lecture where we did the income and + + + align:start position:0% +this lecture where we did the income and +substitution effects + + align:start position:0% +substitution effects + + + align:start position:0% +substitution effects +these guys + + align:start position:0% +these guys + + + align:start position:0% +these guys +and then we decomposed + + align:start position:0% +and then we decomposed + + + align:start position:0% +and then we decomposed +the total demand change + + align:start position:0% +the total demand change + + + align:start position:0% +the total demand change +as a consequence of the price change + + align:start position:0% +as a consequence of the price change + + + align:start position:0% +as a consequence of the price change +into the substitution effect + + align:start position:0% +into the substitution effect + + + align:start position:0% +into the substitution effect +and the income effect + + align:start position:0% +and the income effect + + + align:start position:0% +and the income effect +and we had to clarify that the income + + align:start position:0% +and we had to clarify that the income + + + align:start position:0% +and we had to clarify that the income +effect was negative because in that + + align:start position:0% +effect was negative because in that + + + align:start position:0% +effect was negative because in that +diagram we had p on the wrong axis + + align:start position:0% +diagram we had p on the wrong axis + + + align:start position:0% +diagram we had p on the wrong axis +given the strange way economists + + align:start position:0% +given the strange way economists + + + align:start position:0% +given the strange way economists +invented demand curves okay so then + + align:start position:0% +invented demand curves okay so then + + + align:start position:0% +invented demand curves okay so then +what we're trying to do today is to get + + align:start position:0% +what we're trying to do today is to get + + + align:start position:0% +what we're trying to do today is to get +this substitution effect matrix and + + align:start position:0% +this substitution effect matrix and + + + align:start position:0% +this substitution effect matrix and +we're getting it from observables + + align:start position:0% +we're getting it from observables + + + align:start position:0% +we're getting it from observables +how demand is changing as price changes + + align:start position:0% +how demand is changing as price changes + + + align:start position:0% +how demand is changing as price changes +plus + + align:start position:0% +plus + + + align:start position:0% +plus +how demand is changing as income is + + align:start position:0% +how demand is changing as income is + + + align:start position:0% +how demand is changing as income is +changing + + align:start position:0% +changing + + + align:start position:0% +changing +so this simple example equation is + + align:start position:0% +so this simple example equation is + + + align:start position:0% +so this simple example equation is +elaborated in this slutsky matrix the + + align:start position:0% +elaborated in this slutsky matrix the + + + align:start position:0% +elaborated in this slutsky matrix the +sign changes only because we change + + align:start position:0% +sign changes only because we change + + + align:start position:0% +sign changes only because we change +what's on the left-hand side from the + + align:start position:0% +what's on the left-hand side from the + + + align:start position:0% +what's on the left-hand side from the +total demand to the substitution effect + + align:start position:0% +total demand to the substitution effect + + + align:start position:0% +total demand to the substitution effect +substitute fact equals total demand plus + + align:start position:0% +substitute fact equals total demand plus + + + align:start position:0% +substitute fact equals total demand plus +income changes substitution effect + + align:start position:0% +income changes substitution effect + + + align:start position:0% +income changes substitution effect +equals the change in total demand plus + + align:start position:0% +equals the change in total demand plus + + + align:start position:0% +equals the change in total demand plus +income changes so in fact the slutsky + + align:start position:0% +income changes so in fact the slutsky + + + align:start position:0% +income changes so in fact the slutsky +thing is really familiar to you + + align:start position:0% +thing is really familiar to you + + + align:start position:0% +thing is really familiar to you +from that entire lecture that we did on + + align:start position:0% +from that entire lecture that we did on + + + align:start position:0% +from that entire lecture that we did on +income and substitution effects + + align:start position:0% +income and substitution effects + + + align:start position:0% +income and substitution effects +and now back to the point to reiterate + + align:start position:0% +and now back to the point to reiterate + + + align:start position:0% +and now back to the point to reiterate +this thing + + align:start position:0% +this thing + + + align:start position:0% +this thing +under the assumptions on the previous + + align:start position:0% +under the assumptions on the previous + + + align:start position:0% +under the assumptions on the previous +slide has to be if we enumerated it out + + align:start position:0% +slide has to be if we enumerated it out + + + align:start position:0% +slide has to be if we enumerated it out +for all l and k + + align:start position:0% +for all l and k + + + align:start position:0% +for all l and k +a symmetric negative semi-definite + + align:start position:0% +a symmetric negative semi-definite + + + align:start position:0% +a symmetric negative semi-definite +matrix + + align:start position:0% +matrix + + + align:start position:0% +matrix +so we can fill in the i the row com + + align:start position:0% +so we can fill in the i the row com + + + align:start position:0% +so we can fill in the i the row com +column elements + + align:start position:0% +column elements + + + align:start position:0% +column elements +from all these observables and just + + align:start position:0% +from all these observables and just + + + align:start position:0% +from all these observables and just +check and see whether it's true + + align:start position:0% +check and see whether it's true + + + align:start position:0% +check and see whether it's true +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +i should have said + + align:start position:0% +i should have said + + + align:start position:0% +i should have said +this is with infinite data because you + + align:start position:0% +this is with infinite data because you + + + align:start position:0% +this is with infinite data because you +know we're talking about having + + align:start position:0% +know we're talking about having + + + align:start position:0% +know we're talking about having +derivatives which is infinitesimally + + align:start position:0% +derivatives which is infinitesimally + + + align:start position:0% +derivatives which is infinitesimally +small data but it's still good to know + + align:start position:0% +small data but it's still good to know + + + align:start position:0% +small data but it's still good to know +that in principle there's a way to do it + + align:start position:0% +that in principle there's a way to do it + + + align:start position:0% +that in principle there's a way to do it +if you can't identify something with + + align:start position:0% +if you can't identify something with + + + align:start position:0% +if you can't identify something with +infinite data you're not going to + + align:start position:0% +infinite data you're not going to + + + align:start position:0% +infinite data you're not going to +identify something with finite data + + align:start position:0% +identify something with finite data + + + align:start position:0% +identify something with finite data +so let's review where we are + + align:start position:0% +so let's review where we are + + + align:start position:0% +so let's review where we are +the goal here is see whether we have + + align:start position:0% +the goal here is see whether we have + + + align:start position:0% +the goal here is see whether we have +testable restrictions + + align:start position:0% +testable restrictions + + + align:start position:0% +testable restrictions +in particular ask the question whether + + align:start position:0% +in particular ask the question whether + + + align:start position:0% +in particular ask the question whether +what we see in terms of the demand + + align:start position:0% +what we see in terms of the demand + + + align:start position:0% +what we see in terms of the demand +function + + align:start position:0% +function + + + align:start position:0% +function +came from a utility maximizing rational + + align:start position:0% +came from a utility maximizing rational + + + align:start position:0% +came from a utility maximizing rational +consumer or not so i'm just going to + + align:start position:0% +consumer or not so i'm just going to + + + align:start position:0% +consumer or not so i'm just going to +stick you with a big database in this + + align:start position:0% +stick you with a big database in this + + + align:start position:0% +stick you with a big database in this +case an infinite dimensional database + + align:start position:0% +case an infinite dimensional database + + + align:start position:0% +case an infinite dimensional database +and have you check and see whether it + + align:start position:0% +and have you check and see whether it + + + align:start position:0% +and have you check and see whether it +could have come from a rational + + align:start position:0% +could have come from a rational + + + align:start position:0% +could have come from a rational +maximizing maximizing some utility + + align:start position:0% +maximizing maximizing some utility + + + align:start position:0% +maximizing maximizing some utility +function consumer okay + + align:start position:0% +function consumer okay + + + align:start position:0% +function consumer okay +so + + align:start position:0% +so + + + align:start position:0% +so +what are the three properties + + align:start position:0% +what are the three properties + + + align:start position:0% +what are the three properties +homogeneity of degree zero + + align:start position:0% +homogeneity of degree zero + + + align:start position:0% +homogeneity of degree zero +again + + align:start position:0% +again + + + align:start position:0% +again +multiplying income and prices by a + + align:start position:0% +multiplying income and prices by a + + + align:start position:0% +multiplying income and prices by a +scalar you just get nothing changes + + align:start position:0% +scalar you just get nothing changes + + + align:start position:0% +scalar you just get nothing changes +that's a statement about you know not + + align:start position:0% +that's a statement about you know not + + + align:start position:0% +that's a statement about you know not +being + + align:start position:0% +being + + + align:start position:0% +being +naive about inflation for example + + align:start position:0% +naive about inflation for example + + + align:start position:0% +naive about inflation for example +although i guess arguably + + align:start position:0% +although i guess arguably + + + align:start position:0% +although i guess arguably +it could be violated but it seems + + align:start position:0% +it could be violated but it seems + + + align:start position:0% +it could be violated but it seems +pretty reasonable for a thoughtful + + align:start position:0% +pretty reasonable for a thoughtful + + + align:start position:0% +pretty reasonable for a thoughtful +consumer + + align:start position:0% +consumer + + + align:start position:0% +consumer +in two different situations with prices + + align:start position:0% +in two different situations with prices + + + align:start position:0% +in two different situations with prices +and income just being multiples of one + + align:start position:0% +and income just being multiples of one + + + align:start position:0% +and income just being multiples of one +another they shouldn't change what they + + align:start position:0% +another they shouldn't change what they + + + align:start position:0% +another they shouldn't change what they +do + + align:start position:0% +do + + + align:start position:0% +do +the second property is called vol ross + + align:start position:0% +the second property is called vol ross + + + align:start position:0% +the second property is called vol ross +law + + align:start position:0% +law + + + align:start position:0% +law +which is a fancy name for spending all + + align:start position:0% +which is a fancy name for spending all + + + align:start position:0% +which is a fancy name for spending all +your money + + align:start position:0% +your money + + + align:start position:0% +your money +namely if you have wealth w + + align:start position:0% +namely if you have wealth w + + + align:start position:0% +namely if you have wealth w +and you add up all the expenses observed + + align:start position:0% +and you add up all the expenses observed + + + align:start position:0% +and you add up all the expenses observed +to take place at prices p + + align:start position:0% +to take place at prices p + + + align:start position:0% +to take place at prices p +that's also equal to your wealth so you + + align:start position:0% +that's also equal to your wealth so you + + + align:start position:0% +that's also equal to your wealth so you +don't underspend you can't overspend + + align:start position:0% +don't underspend you can't overspend + + + align:start position:0% +don't underspend you can't overspend +because that would violate the budget + + align:start position:0% +because that would violate the budget + + + align:start position:0% +because that would violate the budget +you don't have the money + + align:start position:0% +you don't have the money + + + align:start position:0% +you don't have the money +but you could in principle under spend + + align:start position:0% +but you could in principle under spend + + + align:start position:0% +but you could in principle under spend +however + + align:start position:0% +however + + + align:start position:0% +however +a rational consumer with local + + align:start position:0% +a rational consumer with local + + + align:start position:0% +a rational consumer with local +non-satiated preferences would never do + + align:start position:0% +non-satiated preferences would never do + + + align:start position:0% +non-satiated preferences would never do +that + + align:start position:0% +that + + + align:start position:0% +that +they'd go right out to the budget + + align:start position:0% +they'd go right out to the budget + + + align:start position:0% +they'd go right out to the budget +technically + + align:start position:0% +technically + + + align:start position:0% +technically +vol ross law is used to mean you only + + align:start position:0% +vol ross law is used to mean you only + + + align:start position:0% +vol ross law is used to mean you only +need to solve for the equilibrium if + + align:start position:0% +need to solve for the equilibrium if + + + align:start position:0% +need to solve for the equilibrium if +there are capital l goods you only need + + align:start position:0% +there are capital l goods you only need + + + align:start position:0% +there are capital l goods you only need +to solve for the equilibrium in l minus + + align:start position:0% +to solve for the equilibrium in l minus + + + align:start position:0% +to solve for the equilibrium in l minus +one of them because the elf one + + align:start position:0% +one of them because the elf one + + + align:start position:0% +one of them because the elf one +is pinned down + + align:start position:0% +is pinned down + + + align:start position:0% +is pinned down +by this budget equation + + align:start position:0% +by this budget equation + + + align:start position:0% +by this budget equation +so there's kind of like no extra + + align:start position:0% +so there's kind of like no extra + + + align:start position:0% +so there's kind of like no extra +restrictions + + align:start position:0% +restrictions + + + align:start position:0% +restrictions +okay and finally the slutsky matrix if + + align:start position:0% +okay and finally the slutsky matrix if + + + align:start position:0% +okay and finally the slutsky matrix if +the demand function is differentiable + + align:start position:0% +the demand function is differentiable + + + align:start position:0% +the demand function is differentiable +and single valued + + align:start position:0% +and single valued + + + align:start position:0% +and single valued +then that + + align:start position:0% +then that + + + align:start position:0% +then that +matrix s of p and w is symmetric and + + align:start position:0% +matrix s of p and w is symmetric and + + + align:start position:0% +matrix s of p and w is symmetric and +negative semi-definite + + align:start position:0% +negative semi-definite + + + align:start position:0% +negative semi-definite +okay who cares + + align:start position:0% +okay who cares + + + align:start position:0% +okay who cares +here's the content + + align:start position:0% +here's the content + + + align:start position:0% +here's the content +if the other two things are true + + align:start position:0% +if the other two things are true + + + align:start position:0% +if the other two things are true +and which one would argue is likely to + + align:start position:0% +and which one would argue is likely to + + + align:start position:0% +and which one would argue is likely to +be true in any generated data set + + align:start position:0% +be true in any generated data set + + + align:start position:0% +be true in any generated data set +if you can find anything that's not + + align:start position:0% +if you can find anything that's not + + + align:start position:0% +if you can find anything that's not +symmetric or not negative semi-definite + + align:start position:0% +symmetric or not negative semi-definite + + + align:start position:0% +symmetric or not negative semi-definite +then preferences could not have come + + align:start position:0% +then preferences could not have come + + + align:start position:0% +then preferences could not have come +from a locally not from locally + + align:start position:0% +from a locally not from locally + + + align:start position:0% +from a locally not from locally +non-satiated preference as a solution to + + align:start position:0% +non-satiated preference as a solution to + + + align:start position:0% +non-satiated preference as a solution to +the max problem + + align:start position:0% +the max problem + + + align:start position:0% +the max problem +so + + align:start position:0% +so + + + align:start position:0% +so +this is sort of the necessity part if + + align:start position:0% +this is sort of the necessity part if + + + align:start position:0% +this is sort of the necessity part if +we have utility max then all three + + align:start position:0% +we have utility max then all three + + + align:start position:0% +we have utility max then all three +properties have to hold + + align:start position:0% +properties have to hold + + + align:start position:0% +properties have to hold +otherwise can't be true that it came + + align:start position:0% +otherwise can't be true that it came + + + align:start position:0% +otherwise can't be true that it came +from utility max problem + + align:start position:0% +from utility max problem + + + align:start position:0% +from utility max problem +now one thing we'll get to convexity in + + align:start position:0% +now one thing we'll get to convexity in + + + align:start position:0% +now one thing we'll get to convexity in +a minute + + align:start position:0% +a minute + + + align:start position:0% +a minute +but i'll just earmark that + + align:start position:0% +but i'll just earmark that + + + align:start position:0% +but i'll just earmark that +that there's no statement here about + + align:start position:0% +that there's no statement here about + + + align:start position:0% +that there's no statement here about +convexity it's just locally non-satiated + + align:start position:0% +convexity it's just locally non-satiated + + + align:start position:0% +convexity it's just locally non-satiated +preferences + + align:start position:0% +preferences + + + align:start position:0% +preferences +it's not quite fair + + align:start position:0% +it's not quite fair + + + align:start position:0% +it's not quite fair +the slutsky thing we derived did rely on + + align:start position:0% +the slutsky thing we derived did rely on + + + align:start position:0% +the slutsky thing we derived did rely on +at least the way i presented it it + + align:start position:0% +at least the way i presented it it + + + align:start position:0% +at least the way i presented it it +relied on convex preferences + + align:start position:0% +relied on convex preferences + + + align:start position:0% +relied on convex preferences +the question here + + align:start position:0% +the question here + + + align:start position:0% +the question here +is whether one can test for non-convex + + align:start position:0% +is whether one can test for non-convex + + + align:start position:0% +is whether one can test for non-convex +preferences + + align:start position:0% +preferences + + + align:start position:0% +preferences +with the data which is a bit of a + + align:start position:0% +with the data which is a bit of a + + + align:start position:0% +with the data which is a bit of a +different question and and i'll come + + align:start position:0% +different question and and i'll come + + + align:start position:0% +different question and and i'll come +back to that + + align:start position:0% +back to that + + + align:start position:0% +back to that +so those three properties are + + align:start position:0% +so those three properties are + + + align:start position:0% +so those three properties are +not only have to be true if we maximize + + align:start position:0% +not only have to be true if we maximize + + + align:start position:0% +not only have to be true if we maximize +utility + + align:start position:0% +utility + + + align:start position:0% +utility +but if they're true in the data then we + + align:start position:0% +but if they're true in the data then we + + + align:start position:0% +but if they're true in the data then we +can always find a utility function that + + align:start position:0% +can always find a utility function that + + + align:start position:0% +can always find a utility function that +generated the observations and that's + + align:start position:0% +generated the observations and that's + + + align:start position:0% +generated the observations and that's +called integrability let me give you the + + align:start position:0% +called integrability let me give you the + + + align:start position:0% +called integrability let me give you the +formal statement of it + + align:start position:0% +formal statement of it + + + align:start position:0% +formal statement of it +so this is like the sufficient part + + align:start position:0% +so this is like the sufficient part + + + align:start position:0% +so this is like the sufficient part +if preferences are of a household + + align:start position:0% +if preferences are of a household + + + align:start position:0% +if preferences are of a household +are strictly increasing strictly + + align:start position:0% +are strictly increasing strictly + + + align:start position:0% +are strictly increasing strictly +quasi-concave + + align:start position:0% +quasi-concave + + + align:start position:0% +quasi-concave +then the voracion demand function + + align:start position:0% +then the voracion demand function + + + align:start position:0% +then the voracion demand function +is homogeneous of degree zero + + align:start position:0% +is homogeneous of degree zero + + + align:start position:0% +is homogeneous of degree zero +satisfies vol ross law + + align:start position:0% +satisfies vol ross law + + + align:start position:0% +satisfies vol ross law +and and its slotsky matrix is symmetric + + align:start position:0% +and and its slotsky matrix is symmetric + + + align:start position:0% +and and its slotsky matrix is symmetric +and negative semi-definite + + align:start position:0% +and negative semi-definite + + + align:start position:0% +and negative semi-definite +that's the first part + + align:start position:0% +that's the first part + + + align:start position:0% +that's the first part +the second part is if the demand + + align:start position:0% +the second part is if the demand + + + align:start position:0% +the second part is if the demand +function + + align:start position:0% +function + + + align:start position:0% +function +is homogeneous of degree zero + + align:start position:0% +is homogeneous of degree zero + + + align:start position:0% +is homogeneous of degree zero +satisfies volara's law + + align:start position:0% +satisfies volara's law + + + align:start position:0% +satisfies volara's law +and the slutsky matrix is symmetric and + + align:start position:0% +and the slutsky matrix is symmetric and + + + align:start position:0% +and the slutsky matrix is symmetric and +negative semi-definite then + + align:start position:0% +negative semi-definite then + + + align:start position:0% +negative semi-definite then +there exists a utility function that is + + align:start position:0% +there exists a utility function that is + + + align:start position:0% +there exists a utility function that is +increasing + + align:start position:0% +increasing + + + align:start position:0% +increasing +quasi-concave that would generate + + align:start position:0% +quasi-concave that would generate + + + align:start position:0% +quasi-concave that would generate +the observed data + + align:start position:0% +the observed data + + + align:start position:0% +the observed data +so let me backtrack this first part a is + + align:start position:0% +so let me backtrack this first part a is + + + align:start position:0% +so let me backtrack this first part a is +what we did initially the second part b + + align:start position:0% +what we did initially the second part b + + + align:start position:0% +what we did initially the second part b +is the integrability theorem that says + + align:start position:0% +is the integrability theorem that says + + + align:start position:0% +is the integrability theorem that says +we can work backwards from the data set + + align:start position:0% +we can work backwards from the data set + + + align:start position:0% +we can work backwards from the data set +to an underlying utility function which + + align:start position:0% +to an underlying utility function which + + + align:start position:0% +to an underlying utility function which +again + + align:start position:0% +again + + + align:start position:0% +again +has to be increasing quasi concave + + align:start position:0% +has to be increasing quasi concave + + + align:start position:0% +has to be increasing quasi concave +and would generate the data as if a + + align:start position:0% +and would generate the data as if a + + + align:start position:0% +and would generate the data as if a +solution to the max problem so + + align:start position:0% +solution to the max problem so + + + align:start position:0% +solution to the max problem so +this is the bit about not testability of + + align:start position:0% +this is the bit about not testability of + + + align:start position:0% +this is the bit about not testability of +convex preferences + + align:start position:0% +convex preferences + + + align:start position:0% +convex preferences +and the idea is we've deliberately drawn + + align:start position:0% +and the idea is we've deliberately drawn + + + align:start position:0% +and the idea is we've deliberately drawn +an underlying utility function + + align:start position:0% +an underlying utility function + + + align:start position:0% +an underlying utility function +which is not concave or these upper + + align:start position:0% +which is not concave or these upper + + + align:start position:0% +which is not concave or these upper +contour sets are not strictly convex you + + align:start position:0% +contour sets are not strictly convex you + + + align:start position:0% +contour sets are not strictly convex you +see the the wiggle here + + align:start position:0% +see the the wiggle here + + + align:start position:0% +see the the wiggle here +but if we start rotating a budget line + + align:start position:0% +but if we start rotating a budget line + + + align:start position:0% +but if we start rotating a budget line +or along the indifference curve and + + align:start position:0% +or along the indifference curve and + + + align:start position:0% +or along the indifference curve and +picking out the tangencies + + align:start position:0% +picking out the tangencies + + + align:start position:0% +picking out the tangencies +we would generate like the hixing demand + + align:start position:0% +we would generate like the hixing demand + + + align:start position:0% +we would generate like the hixing demand +etc then we get to this particular + + align:start position:0% +etc then we get to this particular + + + align:start position:0% +etc then we get to this particular +budget line + + align:start position:0% +budget line + + + align:start position:0% +budget line +where we no longer pivoting + + align:start position:0% +where we no longer pivoting + + + align:start position:0% +where we no longer pivoting +we jump or for a moment we would be + + align:start position:0% +we jump or for a moment we would be + + + align:start position:0% +we jump or for a moment we would be +indifferent between this point and this + + align:start position:0% +indifferent between this point and this + + + align:start position:0% +indifferent between this point and this +point and as we keep rotating the line + + align:start position:0% +point and as we keep rotating the line + + + align:start position:0% +point and as we keep rotating the line +and making it have less and less slope + + align:start position:0% +and making it have less and less slope + + + align:start position:0% +and making it have less and less slope +we will start finding you know pivoting + + align:start position:0% +we will start finding you know pivoting + + + align:start position:0% +we will start finding you know pivoting +along this curved indifference curve + + align:start position:0% +along this curved indifference curve + + + align:start position:0% +along this curved indifference curve +that shouldn't be bending back up again + + align:start position:0% +that shouldn't be bending back up again + + + align:start position:0% +that shouldn't be bending back up again +but anyway so the point is we never end + + align:start position:0% +but anyway so the point is we never end + + + align:start position:0% +but anyway so the point is we never end +up in this non-concave portion so we + + align:start position:0% +up in this non-concave portion so we + + + align:start position:0% +up in this non-concave portion so we +don't generate observables in there what + + align:start position:0% +don't generate observables in there what + + + align:start position:0% +don't generate observables in there what +we would infer + + align:start position:0% +we would infer + + + align:start position:0% +we would infer +is they have strictly concave or weekly + + align:start position:0% +is they have strictly concave or weekly + + + align:start position:0% +is they have strictly concave or weekly +linear preferences over certain ranges + + align:start position:0% +linear preferences over certain ranges + + + align:start position:0% +linear preferences over certain ranges +of prices + + align:start position:0% +of prices + + + align:start position:0% +of prices +which is consistent with underlying + + align:start position:0% +which is consistent with underlying + + + align:start position:0% +which is consistent with underlying +quasi-weekly quasi-concave utility + + align:start position:0% +quasi-weekly quasi-concave utility + + + align:start position:0% +quasi-weekly quasi-concave utility +function + + align:start position:0% +function + + + align:start position:0% +function +now this doesn't mean that we can't test + + align:start position:0% +now this doesn't mean that we can't test + + + align:start position:0% +now this doesn't mean that we can't test +for convexity of preferences in other + + align:start position:0% +for convexity of preferences in other + + + align:start position:0% +for convexity of preferences in other +ways but this whole lecture is about + + align:start position:0% +ways but this whole lecture is about + + + align:start position:0% +ways but this whole lecture is about +restrictions on data that come from + + align:start position:0% +restrictions on data that come from + + + align:start position:0% +restrictions on data that come from +market behavior maximizing utilities + + align:start position:0% +market behavior maximizing utilities + + + align:start position:0% +market behavior maximizing utilities +subject to budgets and if that's all we + + align:start position:0% +subject to budgets and if that's all we + + + align:start position:0% +subject to budgets and if that's all we +have in the data we cannot test for + + align:start position:0% +have in the data we cannot test for + + + align:start position:0% +have in the data we cannot test for +convexity + + align:start position:0% +convexity + + + align:start position:0% +convexity +again the statement there exists a + + align:start position:0% +again the statement there exists a + + + align:start position:0% +again the statement there exists a +utility function that is increasing in + + align:start position:0% +utility function that is increasing in + + + align:start position:0% +utility function that is increasing in +quasi-concave + + align:start position:0% +quasi-concave + + + align:start position:0% +quasi-concave +that's probably confusing because it + + align:start position:0% +that's probably confusing because it + + + align:start position:0% +that's probably confusing because it +looks like we just said the utility + + align:start position:0% +looks like we just said the utility + + + align:start position:0% +looks like we just said the utility +function is quasi-concave + + align:start position:0% +function is quasi-concave + + + align:start position:0% +function is quasi-concave +no + + align:start position:0% +no + + + align:start position:0% +no +this one is not + + align:start position:0% +this one is not + + + align:start position:0% +this one is not +that's the true underlying function but + + align:start position:0% +that's the true underlying function but + + + align:start position:0% +that's the true underlying function but +we can't test for that + + align:start position:0% +we can't test for that + + + align:start position:0% +we can't test for that +all we see in the observables are you + + align:start position:0% +all we see in the observables are you + + + align:start position:0% +all we see in the observables are you +know the one that as if generated the + + align:start position:0% +know the one that as if generated the + + + align:start position:0% +know the one that as if generated the +dashed line + + align:start position:0% +dashed line + + + align:start position:0% +dashed line +and that utility function is quasi + + align:start position:0% +and that utility function is quasi + + + align:start position:0% +and that utility function is quasi +concave so that's the content of + + align:start position:0% +concave so that's the content of + + + align:start position:0% +concave so that's the content of +of this statement it's as if there were + + align:start position:0% +of this statement it's as if there were + + + align:start position:0% +of this statement it's as if there were +a utility function which is quasi + + align:start position:0% +a utility function which is quasi + + + align:start position:0% +a utility function which is quasi +concave + + align:start position:0% +concave + + + align:start position:0% +concave +questions + + align:start position:0% +questions + + + align:start position:0% +questions +all right + + align:start position:0% +all right + + + align:start position:0% +all right +so operationally we might as well assume + + align:start position:0% +so operationally we might as well assume + + + align:start position:0% +so operationally we might as well assume +convex preferences because we're not + + align:start position:0% +convex preferences because we're not + + + align:start position:0% +convex preferences because we're not +going to be able to reject it anyway + + align:start position:0% +going to be able to reject it anyway + + + align:start position:0% +going to be able to reject it anyway +that's kind of a odd sounding corollary + + align:start position:0% +that's kind of a odd sounding corollary + + + align:start position:0% +that's kind of a odd sounding corollary +to this whole first part of the lecture + + align:start position:0% +to this whole first part of the lecture + + + align:start position:0% +to this whole first part of the lecture +which is the goal of placing + + align:start position:0% +which is the goal of placing + + + align:start position:0% +which is the goal of placing +restrictions on data whether data place + + align:start position:0% +restrictions on data whether data place + + + align:start position:0% +restrictions on data whether data place +restrictions on theory or not and + + align:start position:0% +restrictions on theory or not and + + + align:start position:0% +restrictions on theory or not and +finally let me say again + + align:start position:0% +finally let me say again + + + align:start position:0% +finally let me say again +why are we trying so hard to see what we + + align:start position:0% +why are we trying so hard to see what we + + + align:start position:0% +why are we trying so hard to see what we +could potentially reject i mean the + + align:start position:0% +could potentially reject i mean the + + + align:start position:0% +could potentially reject i mean the +answer is if say it's not slitsky then + + align:start position:0% +answer is if say it's not slitsky then + + + align:start position:0% +answer is if say it's not slitsky then +it could not have come from you know a + + align:start position:0% +it could not have come from you know a + + + align:start position:0% +it could not have come from you know a +rational consumer maximizing utility and + + align:start position:0% +rational consumer maximizing utility and + + + align:start position:0% +rational consumer maximizing utility and +that's kind of good news + + align:start position:0% +that's kind of good news + + + align:start position:0% +that's kind of good news +if for any data set we can always find a + + align:start position:0% +if for any data set we can always find a + + + align:start position:0% +if for any data set we can always find a +consumer maximizing utility that could + + align:start position:0% +consumer maximizing utility that could + + + align:start position:0% +consumer maximizing utility that could +have generated the data then there's no + + align:start position:0% +have generated the data then there's no + + + align:start position:0% +have generated the data then there's no +content to the theory + + align:start position:0% +content to the theory + + + align:start position:0% +content to the theory +it might be fun to do the theory + + align:start position:0% +it might be fun to do the theory + + + align:start position:0% +it might be fun to do the theory +but it's a vacuous empirical exercise it + + align:start position:0% +but it's a vacuous empirical exercise it + + + align:start position:0% +but it's a vacuous empirical exercise it +has no content if it's always true + + align:start position:0% +has no content if it's always true + + + align:start position:0% +has no content if it's always true +fortunately it's not always true and + + align:start position:0% +fortunately it's not always true and + + + align:start position:0% +fortunately it's not always true and +these are the conditions we can check + + align:start position:0% +these are the conditions we can check + + + align:start position:0% +these are the conditions we can check +it's an odd thing because then you could + + align:start position:0% +it's an odd thing because then you could + + + align:start position:0% +it's an odd thing because then you could +end up with oh my god where did this + + align:start position:0% +end up with oh my god where did this + + + align:start position:0% +end up with oh my god where did this +data come from it couldn't be coming + + align:start position:0% +data come from it couldn't be coming + + + align:start position:0% +data come from it couldn't be coming +from a rational consumer but anyway + + align:start position:0% +from a rational consumer but anyway + + + align:start position:0% +from a rational consumer but anyway +we actually like it if we can reject + + align:start position:0% +we actually like it if we can reject + + + align:start position:0% +we actually like it if we can reject +things + + align:start position:0% +things + + + align:start position:0% +things +strange science + + align:start position:0% +strange science + + + align:start position:0% +strange science +so now let's go to finite data + + align:start position:0% +so now let's go to finite data + + + align:start position:0% +so now let's go to finite data +we had observed a minute ago we had the + + align:start position:0% +we had observed a minute ago we had the + + + align:start position:0% +we had observed a minute ago we had the +entire vol raising demand function for + + align:start position:0% +entire vol raising demand function for + + + align:start position:0% +entire vol raising demand function for +arbitrarily small changes in prices and + + align:start position:0% +arbitrarily small changes in prices and + + + align:start position:0% +arbitrarily small changes in prices and +wealth and so on but typically we don't + + align:start position:0% +wealth and so on but typically we don't + + + align:start position:0% +wealth and so on but typically we don't +see that we don't have an infinite data + + align:start position:0% +see that we don't have an infinite data + + + align:start position:0% +see that we don't have an infinite data +set + + align:start position:0% +set + + + align:start position:0% +set +we may have a household and if we're + + align:start position:0% +we may have a household and if we're + + + align:start position:0% +we may have a household and if we're +lucky we can observe that household over + + align:start position:0% +lucky we can observe that household over + + + align:start position:0% +lucky we can observe that household over +long periods of time and see you know + + align:start position:0% +long periods of time and see you know + + + align:start position:0% +long periods of time and see you know +what decisions are being made + + align:start position:0% +what decisions are being made + + + align:start position:0% +what decisions are being made +if those things are recorded on alipay + + align:start position:0% +if those things are recorded on alipay + + + align:start position:0% +if those things are recorded on alipay +for example + + align:start position:0% +for example + + + align:start position:0% +for example +and if it were true that everything that + + align:start position:0% +and if it were true that everything that + + + align:start position:0% +and if it were true that everything that +was bought where it's acquired on alipay + + align:start position:0% +was bought where it's acquired on alipay + + + align:start position:0% +was bought where it's acquired on alipay +then we would see + + align:start position:0% +then we would see + + + align:start position:0% +then we would see +and if we also saw the wealth because + + align:start position:0% +and if we also saw the wealth because + + + align:start position:0% +and if we also saw the wealth because +they're spending everything on alipay + + align:start position:0% +they're spending everything on alipay + + + align:start position:0% +they're spending everything on alipay +then we would actually potentially have + + align:start position:0% +then we would actually potentially have + + + align:start position:0% +then we would actually potentially have +a very long data set but not infinite so + + align:start position:0% +a very long data set but not infinite so + + + align:start position:0% +a very long data set but not infinite so +we want to see whether we can + + align:start position:0% +we want to see whether we can + + + align:start position:0% +we want to see whether we can +nevertheless test the hypothesis of + + align:start position:0% +nevertheless test the hypothesis of + + + align:start position:0% +nevertheless test the hypothesis of +rationality and the answer is going to + + align:start position:0% +rationality and the answer is going to + + + align:start position:0% +rationality and the answer is going to +be positive there is a way to take the + + align:start position:0% +be positive there is a way to take the + + + align:start position:0% +be positive there is a way to take the +data and run an algorithm + + align:start position:0% +data and run an algorithm + + + align:start position:0% +data and run an algorithm +and uh see whether the results are + + align:start position:0% +and uh see whether the results are + + + align:start position:0% +and uh see whether the results are +consistent but potentially inconsistent + + align:start position:0% +consistent but potentially inconsistent + + + align:start position:0% +consistent but potentially inconsistent +and in the latter case we can reject + + align:start position:0% +and in the latter case we can reject + + + align:start position:0% +and in the latter case we can reject +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +this is the definition of the weak axiom + + align:start position:0% +this is the definition of the weak axiom + + + align:start position:0% +this is the definition of the weak axiom +of revealed preference + + align:start position:0% +of revealed preference + + + align:start position:0% +of revealed preference +let's start with just having + + align:start position:0% +let's start with just having + + + align:start position:0% +let's start with just having +two observations with different prices + + align:start position:0% +two observations with different prices + + + align:start position:0% +two observations with different prices +and different choices okay p1 x1 p2 x2 + + align:start position:0% +and different choices okay p1 x1 p2 x2 + + + align:start position:0% +and different choices okay p1 x1 p2 x2 +is a pair of observations on prices and + + align:start position:0% +is a pair of observations on prices and + + + align:start position:0% +is a pair of observations on prices and +consumption bundles + + align:start position:0% +consumption bundles + + + align:start position:0% +consumption bundles +implicitly for a given household + + align:start position:0% +implicitly for a given household + + + align:start position:0% +implicitly for a given household +p t + + align:start position:0% +p t + + + align:start position:0% +p t +doesn't mean necessarily t over time + + align:start position:0% +doesn't mean necessarily t over time + + + align:start position:0% +doesn't mean necessarily t over time +although you could imagine + + align:start position:0% +although you could imagine + + + align:start position:0% +although you could imagine +we observed at t equal one the first + + align:start position:0% +we observed at t equal one the first + + + align:start position:0% +we observed at t equal one the first +choice and at t equal to the second + + align:start position:0% +choice and at t equal to the second + + + align:start position:0% +choice and at t equal to the second +choice + + align:start position:0% +choice + + + align:start position:0% +choice +but that's confusing because it raises + + align:start position:0% +but that's confusing because it raises + + + align:start position:0% +but that's confusing because it raises +the dynamic issues and everything else + + align:start position:0% +the dynamic issues and everything else + + + align:start position:0% +the dynamic issues and everything else +so + + align:start position:0% +so + + + align:start position:0% +so +t is really only meant here to index the + + align:start position:0% +t is really only meant here to index the + + + align:start position:0% +t is really only meant here to index the +data point + + align:start position:0% +data point + + + align:start position:0% +data point +and there's two data points and hence + + align:start position:0% +and there's two data points and hence + + + align:start position:0% +and there's two data points and hence +two values for t + + align:start position:0% +two values for t + + + align:start position:0% +two values for t +and let's suppose + + align:start position:0% +and let's suppose + + + align:start position:0% +and let's suppose +it's + + align:start position:0% +it's + + + align:start position:0% +it's +not trivial + + align:start position:0% +not trivial + + + align:start position:0% +not trivial +so + + align:start position:0% +so + + + align:start position:0% +so +these choices are different + + align:start position:0% +these choices are different + + + align:start position:0% +these choices are different +and we say the individual choices these + + align:start position:0% +and we say the individual choices these + + + align:start position:0% +and we say the individual choices these +choices satisfy the weak axiom of real + + align:start position:0% +choices satisfy the weak axiom of real + + + align:start position:0% +choices satisfy the weak axiom of real +preference if whenever at the second + + align:start position:0% +preference if whenever at the second + + + align:start position:0% +preference if whenever at the second +price is p2 + + align:start position:0% +price is p2 + + + align:start position:0% +price is p2 +with x2 chosen + + align:start position:0% +with x2 chosen + + + align:start position:0% +with x2 chosen +and x1 in the interior of the budget we + + align:start position:0% +and x1 in the interior of the budget we + + + align:start position:0% +and x1 in the interior of the budget we +must then have at prices p1 spending p1 + + align:start position:0% +must then have at prices p1 spending p1 + + + align:start position:0% +must then have at prices p1 spending p1 +x1 that x2 is not attainable so let me + + align:start position:0% +x1 that x2 is not attainable so let me + + + align:start position:0% +x1 that x2 is not attainable so let me +say it again + + align:start position:0% +say it again + + + align:start position:0% +say it again +it's an if then thing + + align:start position:0% +it's an if then thing + + + align:start position:0% +it's an if then thing +if this is true in the data + + align:start position:0% +if this is true in the data + + + align:start position:0% +if this is true in the data +that if they had chosen x1 they would + + align:start position:0% +that if they had chosen x1 they would + + + align:start position:0% +that if they had chosen x1 they would +not have been + + align:start position:0% +not have been + + + align:start position:0% +not have been +spending all their money + + align:start position:0% +spending all their money + + + align:start position:0% +spending all their money +if that configuration is true in the + + align:start position:0% +if that configuration is true in the + + + align:start position:0% +if that configuration is true in the +data then we better find that at prices + + align:start position:0% +data then we better find that at prices + + + align:start position:0% +data then we better find that at prices +p1 the valuation of expenditures on x2 + + align:start position:0% +p1 the valuation of expenditures on x2 + + + align:start position:0% +p1 the valuation of expenditures on x2 +is strictly greater than x1 + + align:start position:0% +is strictly greater than x1 + + + align:start position:0% +is strictly greater than x1 +and again the ideas revealed preference + + align:start position:0% +and again the ideas revealed preference + + + align:start position:0% +and again the ideas revealed preference +so at prices p2 they are revealed to + + align:start position:0% +so at prices p2 they are revealed to + + + align:start position:0% +so at prices p2 they are revealed to +prefer x2 over x1 + + align:start position:0% +prefer x2 over x1 + + + align:start position:0% +prefer x2 over x1 +because x1 is available and they didn't + + align:start position:0% +because x1 is available and they didn't + + + align:start position:0% +because x1 is available and they didn't +choose it so it better not be the case + + align:start position:0% +choose it so it better not be the case + + + align:start position:0% +choose it so it better not be the case +that in some other way of looking at the + + align:start position:0% +that in some other way of looking at the + + + align:start position:0% +that in some other way of looking at the +data this inequality is violated because + + align:start position:0% +data this inequality is violated because + + + align:start position:0% +data this inequality is violated because +if at prices p1 + + align:start position:0% +if at prices p1 + + + align:start position:0% +if at prices p1 +x2 were available + + align:start position:0% +x2 were available + + + align:start position:0% +x2 were available +because it's interior to the budget at + + align:start position:0% +because it's interior to the budget at + + + align:start position:0% +because it's interior to the budget at +prices p1 then to be consistent they + + align:start position:0% +prices p1 then to be consistent they + + + align:start position:0% +prices p1 then to be consistent they +should have chosen it because it's + + align:start position:0% +should have chosen it because it's + + + align:start position:0% +should have chosen it because it's +already shown to be weekly preferred x1 + + align:start position:0% +already shown to be weekly preferred x1 + + + align:start position:0% +already shown to be weekly preferred x1 +okay so that's the idea + + align:start position:0% +okay so that's the idea + + + align:start position:0% +okay so that's the idea +if this is true then this is true so + + align:start position:0% +if this is true then this is true so + + + align:start position:0% +if this is true then this is true so +it's like a statement of of an algorithm + + align:start position:0% +it's like a statement of of an algorithm + + + align:start position:0% +it's like a statement of of an algorithm +running over the data + + align:start position:0% +running over the data + + + align:start position:0% +running over the data +and we're going to generalize that + + align:start position:0% +and we're going to generalize that + + + align:start position:0% +and we're going to generalize that +so what happens if this isn't true + + align:start position:0% +so what happens if this isn't true + + + align:start position:0% +so what happens if this isn't true +this is true but this is not so let's + + align:start position:0% +this is true but this is not so let's + + + align:start position:0% +this is true but this is not so let's +look at a picture + + align:start position:0% +look at a picture + + + align:start position:0% +look at a picture +at prices p2 + + align:start position:0% +at prices p2 + + + align:start position:0% +at prices p2 +they choose x2 + + align:start position:0% +they choose x2 + + + align:start position:0% +they choose x2 +which on the budget + + align:start position:0% +which on the budget + + + align:start position:0% +which on the budget +and x1 is interior + + align:start position:0% +and x1 is interior + + + align:start position:0% +and x1 is interior +so + + align:start position:0% + + + + align:start position:0% + +that's this condition + + align:start position:0% +that's this condition + + + align:start position:0% +that's this condition +x1 is interior to the budget at prices + + align:start position:0% +x1 is interior to the budget at prices + + + align:start position:0% +x1 is interior to the budget at prices +p2 + + align:start position:0% +p2 + + + align:start position:0% +p2 +then we look at prices p2 p1 + + align:start position:0% +then we look at prices p2 p1 + + + align:start position:0% +then we look at prices p2 p1 +are they + + align:start position:0% +are they + + + align:start position:0% +are they +here + + align:start position:0% +here + + + align:start position:0% +here +so here's x1 it's on the budget at price + + align:start position:0% +so here's x1 it's on the budget at price + + + align:start position:0% +so here's x1 it's on the budget at price +p1 + + align:start position:0% +p1 + + + align:start position:0% +p1 +the question is where is x2 + + align:start position:0% +the question is where is x2 + + + align:start position:0% +the question is where is x2 +in this case x2 is interior + + align:start position:0% +in this case x2 is interior + + + align:start position:0% +in this case x2 is interior +to the p1 budget line + + align:start position:0% +to the p1 budget line + + + align:start position:0% +to the p1 budget line +that violates + + align:start position:0% +that violates + + + align:start position:0% +that violates +we didn't want to find that that + + align:start position:0% +we didn't want to find that that + + + align:start position:0% +we didn't want to find that that +violates + + align:start position:0% +violates + + + align:start position:0% +violates +what ought to be true + + align:start position:0% +what ought to be true + + + align:start position:0% +what ought to be true +and it so it violates the weak axiom + + align:start position:0% +and it so it violates the weak axiom + + + align:start position:0% +and it so it violates the weak axiom +not only that try to draw indifference + + align:start position:0% +not only that try to draw indifference + + + align:start position:0% +not only that try to draw indifference +curves + + align:start position:0% +curves + + + align:start position:0% +curves +from a quasi-concave or you know linear + + align:start position:0% +from a quasi-concave or you know linear + + + align:start position:0% +from a quasi-concave or you know linear +or strictly convex + + align:start position:0% +or strictly convex + + + align:start position:0% +or strictly convex +you can't do it + + align:start position:0% +you can't do it + + + align:start position:0% +you can't do it +you get a tangency here you'd get a + + align:start position:0% +you get a tangency here you'd get a + + + align:start position:0% +you get a tangency here you'd get a +tangency here + + align:start position:0% +tangency here + + + align:start position:0% +tangency here +or you know looking at the bottom + + align:start position:0% +or you know looking at the bottom + + + align:start position:0% +or you know looking at the bottom +the indifference curves would cross + + align:start position:0% +the indifference curves would cross + + + align:start position:0% +the indifference curves would cross +there's no way you can draw this picture + + align:start position:0% +there's no way you can draw this picture + + + align:start position:0% +there's no way you can draw this picture +without crossing the indifference curves + + align:start position:0% +without crossing the indifference curves + + + align:start position:0% +without crossing the indifference curves +and have a tangent at the two choices + + align:start position:0% +and have a tangent at the two choices + + + align:start position:0% +and have a tangent at the two choices +well we learned right in lecture two + + align:start position:0% +well we learned right in lecture two + + + align:start position:0% +well we learned right in lecture two +that indifference curves can't cross for + + align:start position:0% +that indifference curves can't cross for + + + align:start position:0% +that indifference curves can't cross for +rational consumers + + align:start position:0% +rational consumers + + + align:start position:0% +rational consumers +if a is preferred to b b is preferred to + + align:start position:0% +if a is preferred to b b is preferred to + + + align:start position:0% +if a is preferred to b b is preferred to +z a is preferred to c you may remember + + align:start position:0% +z a is preferred to c you may remember + + + align:start position:0% +z a is preferred to c you may remember +that diagram + + align:start position:0% +that diagram + + + align:start position:0% +that diagram +so that's meant to be an intuitive proof + + align:start position:0% +so that's meant to be an intuitive proof + + + align:start position:0% +so that's meant to be an intuitive proof +of the picture + + align:start position:0% +of the picture + + + align:start position:0% +of the picture +of the proposition + + align:start position:0% +of the proposition + + + align:start position:0% +of the proposition +so in conclusion for the weak axiom + + align:start position:0% +so in conclusion for the weak axiom + + + align:start position:0% +so in conclusion for the weak axiom +if the agent has preferences which are + + align:start position:0% +if the agent has preferences which are + + + align:start position:0% +if the agent has preferences which are +locally non-satiated and rational then + + align:start position:0% +locally non-satiated and rational then + + + align:start position:0% +locally non-satiated and rational then +given you know observations on prices + + align:start position:0% +given you know observations on prices + + + align:start position:0% +given you know observations on prices +expenditures and wealth you must have + + align:start position:0% +expenditures and wealth you must have + + + align:start position:0% +expenditures and wealth you must have +that the + + align:start position:0% +that the + + + align:start position:0% +that the +pairs of data points satisfy this weak + + align:start position:0% +pairs of data points satisfy this weak + + + align:start position:0% +pairs of data points satisfy this weak +axiom of revealed preference warp + + align:start position:0% +axiom of revealed preference warp + + + align:start position:0% +axiom of revealed preference warp +okay + + align:start position:0% +okay + + + align:start position:0% +okay +all right so now we want to generalize + + align:start position:0% +all right so now we want to generalize + + + align:start position:0% +all right so now we want to generalize +we have here still two data points just + + align:start position:0% +we have here still two data points just + + + align:start position:0% +we have here still two data points just +slightly different notation + + align:start position:0% +slightly different notation + + + align:start position:0% +slightly different notation +the data points are indexed by t and s + + align:start position:0% +the data points are indexed by t and s + + + align:start position:0% +the data points are indexed by t and s +and we write + + align:start position:0% +and we write + + + align:start position:0% +and we write +that the t data point of x is revealed + + align:start position:0% +that the t data point of x is revealed + + + align:start position:0% +that the t data point of x is revealed +directly preferred to the data point + + align:start position:0% +directly preferred to the data point + + + align:start position:0% +directly preferred to the data point +indexed by s + + align:start position:0% +indexed by s + + + align:start position:0% +indexed by s +if + + align:start position:0% +if + + + align:start position:0% +if +x is available and price is p t + + align:start position:0% +x is available and price is p t + + + align:start position:0% +x is available and price is p t +so again at prices pt they chose xt + + align:start position:0% +so again at prices pt they chose xt + + + align:start position:0% +so again at prices pt they chose xt +that's the way the data are organized + + align:start position:0% +that's the way the data are organized + + + align:start position:0% +that's the way the data are organized +they could have chosen xs because it's + + align:start position:0% +they could have chosen xs because it's + + + align:start position:0% +they could have chosen xs because it's +in the budget but they didn't do it + + align:start position:0% +in the budget but they didn't do it + + + align:start position:0% +in the budget but they didn't do it +so we say you know directly revealed + + align:start position:0% +so we say you know directly revealed + + + align:start position:0% +so we say you know directly revealed +preferred + + align:start position:0% +preferred + + + align:start position:0% +preferred +this might imply strict preference but + + align:start position:0% +this might imply strict preference but + + + align:start position:0% +this might imply strict preference but +you know it doesn't really mean that it + + align:start position:0% +you know it doesn't really mean that it + + + align:start position:0% +you know it doesn't really mean that it +just means as with the axioms of + + align:start position:0% +just means as with the axioms of + + + align:start position:0% +just means as with the axioms of +revealed preference + + align:start position:0% +revealed preference + + + align:start position:0% +revealed preference +what we see is what they want that's all + + align:start position:0% +what we see is what they want that's all + + + align:start position:0% +what we see is what they want that's all +we're saying + + align:start position:0% +we're saying + + + align:start position:0% +we're saying +they're revealed to prefer it then you + + align:start position:0% +they're revealed to prefer it then you + + + align:start position:0% +they're revealed to prefer it then you +know they continue to prefer it + + align:start position:0% +know they continue to prefer it + + + align:start position:0% +know they continue to prefer it +in this case they prefer it over other + + align:start position:0% +in this case they prefer it over other + + + align:start position:0% +in this case they prefer it over other +things they could have chosen and didn't + + align:start position:0% +things they could have chosen and didn't + + + align:start position:0% +things they could have chosen and didn't +pretty simple-minded + + align:start position:0% +pretty simple-minded + + + align:start position:0% +pretty simple-minded +then we come to + + align:start position:0% +then we come to + + + align:start position:0% +then we come to +i almost want to say indirectly revealed + + align:start position:0% +i almost want to say indirectly revealed + + + align:start position:0% +i almost want to say indirectly revealed +preferred actually it's in parentheses + + align:start position:0% +preferred actually it's in parentheses + + + align:start position:0% +preferred actually it's in parentheses +here + + align:start position:0% +here + + + align:start position:0% +here +to contrast with the directly revealed + + align:start position:0% +to contrast with the directly revealed + + + align:start position:0% +to contrast with the directly revealed +preferred so now we're going to have a + + align:start position:0% +preferred so now we're going to have a + + + align:start position:0% +preferred so now we're going to have a +bigger data set we're going to have a + + align:start position:0% +bigger data set we're going to have a + + + align:start position:0% +bigger data set we're going to have a +whole sequence and we say that x t with + + align:start position:0% +whole sequence and we say that x t with + + + align:start position:0% +whole sequence and we say that x t with +r without the d + + align:start position:0% +r without the d + + + align:start position:0% +r without the d +just revealed preferred not directly + + align:start position:0% +just revealed preferred not directly + + + align:start position:0% +just revealed preferred not directly +preferred or if you like i for + + align:start position:0% +preferred or if you like i for + + + align:start position:0% +preferred or if you like i for +indirectly preferred + + align:start position:0% +indirectly preferred + + + align:start position:0% +indirectly preferred +xt is revealed prefer to access if + + align:start position:0% +xt is revealed prefer to access if + + + align:start position:0% +xt is revealed prefer to access if +we have a sequence of data points such + + align:start position:0% +we have a sequence of data points such + + + align:start position:0% +we have a sequence of data points such +that + + align:start position:0% +that + + + align:start position:0% +that +pairwise we have direct revelation + + align:start position:0% +pairwise we have direct revelation + + + align:start position:0% +pairwise we have direct revelation +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +we want xt to at the beginning to can be + + align:start position:0% +we want xt to at the beginning to can be + + + align:start position:0% +we want xt to at the beginning to can be +compared to xs at the end + + align:start position:0% +compared to xs at the end + + + align:start position:0% +compared to xs at the end +but we do that we never see say in the + + align:start position:0% +but we do that we never see say in the + + + align:start position:0% +but we do that we never see say in the +data that they're + + align:start position:0% +data that they're + + + align:start position:0% +data that they're +directly comparable + + align:start position:0% +directly comparable + + + align:start position:0% +directly comparable +instead we see xt + + align:start position:0% +instead we see xt + + + align:start position:0% +instead we see xt +in a situation where + + align:start position:0% +in a situation where + + + align:start position:0% +in a situation where +within the budget xt is revealed + + align:start position:0% +within the budget xt is revealed + + + align:start position:0% +within the budget xt is revealed +directly preferred to xr1 in another + + align:start position:0% +directly preferred to xr1 in another + + + align:start position:0% +directly preferred to xr1 in another +piece of the data we see xr1 is revealed + + align:start position:0% +piece of the data we see xr1 is revealed + + + align:start position:0% +piece of the data we see xr1 is revealed +directly preferred to xr2 and so on down + + align:start position:0% +directly preferred to xr2 and so on down + + + align:start position:0% +directly preferred to xr2 and so on down +the chain + + align:start position:0% +the chain + + + align:start position:0% +the chain +with xrk being revealed directly + + align:start position:0% +with xrk being revealed directly + + + align:start position:0% +with xrk being revealed directly +preferred to xs + + align:start position:0% +preferred to xs + + + align:start position:0% +preferred to xs +this is like the transitivity axiom + + align:start position:0% +this is like the transitivity axiom + + + align:start position:0% +this is like the transitivity axiom +which is part of the axioms of a + + align:start position:0% +which is part of the axioms of a + + + align:start position:0% +which is part of the axioms of a +rational consumer + + align:start position:0% +rational consumer + + + align:start position:0% +rational consumer +right we have a chain in which we have + + align:start position:0% +right we have a chain in which we have + + + align:start position:0% +right we have a chain in which we have +directly revealed preference hence the + + align:start position:0% +directly revealed preference hence the + + + align:start position:0% +directly revealed preference hence the +one at the beginning ought to be + + align:start position:0% +one at the beginning ought to be + + + align:start position:0% +one at the beginning ought to be +indirectly revealed preferred to the one + + align:start position:0% +indirectly revealed preferred to the one + + + align:start position:0% +indirectly revealed preferred to the one +at the end xt access + + align:start position:0% +at the end xt access + + + align:start position:0% +at the end xt access +okay so then we come to the + + align:start position:0% +okay so then we come to the + + + align:start position:0% +okay so then we come to the +generalized axiom of revealed preference + + align:start position:0% +generalized axiom of revealed preference + + + align:start position:0% +generalized axiom of revealed preference +called garp so i don't know there was a + + align:start position:0% +called garp so i don't know there was a + + + align:start position:0% +called garp so i don't know there was a +famous movie the world according to garp + + align:start position:0% +famous movie the world according to garp + + + align:start position:0% +famous movie the world according to garp +i don't know if you was a robin williams + + align:start position:0% +i don't know if you was a robin williams + + + align:start position:0% +i don't know if you was a robin williams +movie they didn't mean this so + + align:start position:0% +movie they didn't mean this so + + + align:start position:0% +movie they didn't mean this so +generalized revealed preference + + align:start position:0% +generalized revealed preference + + + align:start position:0% +generalized revealed preference +is building on this notion of indirectly + + align:start position:0% +is building on this notion of indirectly + + + align:start position:0% +is building on this notion of indirectly +revealed preference + + align:start position:0% +revealed preference + + + align:start position:0% +revealed preference +if we have the data point so the + + align:start position:0% +if we have the data point so the + + + align:start position:0% +if we have the data point so the +dimensionality of the data set is + + align:start position:0% +dimensionality of the data set is + + + align:start position:0% +dimensionality of the data set is +capital t + + align:start position:0% +capital t + + + align:start position:0% +capital t +and we have prices and demands for each + + align:start position:0% +and we have prices and demands for each + + + align:start position:0% +and we have prices and demands for each +t + + align:start position:0% +t + + + align:start position:0% +t +then the general axiom of real + + align:start position:0% +then the general axiom of real + + + align:start position:0% +then the general axiom of real +preference + + align:start position:0% +preference + + + align:start position:0% +preference +means that + + align:start position:0% +means that + + + align:start position:0% +means that +if x t is indirectly revealed to x s + + align:start position:0% +if x t is indirectly revealed to x s + + + align:start position:0% +if x t is indirectly revealed to x s +then if we're able to make the + + align:start position:0% +then if we're able to make the + + + align:start position:0% +then if we're able to make the +comparison we have the strict inequality + + align:start position:0% +comparison we have the strict inequality + + + align:start position:0% +comparison we have the strict inequality +namely + + align:start position:0% +namely + + + align:start position:0% +namely +x t is preferred to access it better be + + align:start position:0% +x t is preferred to access it better be + + + align:start position:0% +x t is preferred to access it better be +the case that at price's ps xt is + + align:start position:0% +the case that at price's ps xt is + + + align:start position:0% +the case that at price's ps xt is +outside the budget relative to the + + align:start position:0% +outside the budget relative to the + + + align:start position:0% +outside the budget relative to the +expenditures on xs and the intuition as + + align:start position:0% +expenditures on xs and the intuition as + + + align:start position:0% +expenditures on xs and the intuition as +i wrote in red at the bottom of the + + align:start position:0% +i wrote in red at the bottom of the + + + align:start position:0% +i wrote in red at the bottom of the +slide + + align:start position:0% +slide + + + align:start position:0% +slide +is simply imagine this inequality is + + align:start position:0% +is simply imagine this inequality is + + + align:start position:0% +is simply imagine this inequality is +reversed then we would have at prices ps + + align:start position:0% +reversed then we would have at prices ps + + + align:start position:0% +reversed then we would have at prices ps +xt is within the budget and xs ought to + + align:start position:0% +xt is within the budget and xs ought to + + + align:start position:0% +xt is within the budget and xs ought to +be at least weekly if not strictly + + align:start position:0% +be at least weekly if not strictly + + + align:start position:0% +be at least weekly if not strictly +preferred + + align:start position:0% +preferred + + + align:start position:0% +preferred +because xs was chosen and xt was + + align:start position:0% +because xs was chosen and xt was + + + align:start position:0% +because xs was chosen and xt was +available so xs would be + + align:start position:0% +available so xs would be + + + align:start position:0% +available so xs would be +directly revealed to be preferred to x t + + align:start position:0% +directly revealed to be preferred to x t + + + align:start position:0% +directly revealed to be preferred to x t +according to this definition but it goes + + align:start position:0% +according to this definition but it goes + + + align:start position:0% +according to this definition but it goes +the other way here where + + align:start position:0% +the other way here where + + + align:start position:0% +the other way here where +x t is revealed granted indirectly to be + + align:start position:0% +x t is revealed granted indirectly to be + + + align:start position:0% +x t is revealed granted indirectly to be +preferred to excess so that if this were + + align:start position:0% +preferred to excess so that if this were + + + align:start position:0% +preferred to excess so that if this were +a weak inequality a strict inequality + + align:start position:0% +a weak inequality a strict inequality + + + align:start position:0% +a weak inequality a strict inequality +going the other way we would intuitively + + align:start position:0% +going the other way we would intuitively + + + align:start position:0% +going the other way we would intuitively +violate these two pieces of information + + align:start position:0% +violate these two pieces of information + + + align:start position:0% +violate these two pieces of information +would not be consistent with each other + + align:start position:0% +would not be consistent with each other + + + align:start position:0% +would not be consistent with each other +now again you should think about this as + + align:start position:0% +now again you should think about this as + + + align:start position:0% +now again you should think about this as +an algorithm you know i just some + + align:start position:0% +an algorithm you know i just some + + + align:start position:0% +an algorithm you know i just some +classes do this i found one on the web + + align:start position:0% +classes do this i found one on the web + + + align:start position:0% +classes do this i found one on the web +today + + align:start position:0% +today + + + align:start position:0% +today +they give students a very large data set + + align:start position:0% +they give students a very large data set + + + align:start position:0% +they give students a very large data set +of prices and quantities and that's to + + align:start position:0% +of prices and quantities and that's to + + + align:start position:0% +of prices and quantities and that's to +ask them is this consistent with a + + align:start position:0% +ask them is this consistent with a + + + align:start position:0% +ask them is this consistent with a +rational household + + align:start position:0% +rational household + + + align:start position:0% +rational household +and how do you approach that well you + + align:start position:0% +and how do you approach that well you + + + align:start position:0% +and how do you approach that well you +start looking for these chains you have + + align:start position:0% +start looking for these chains you have + + + align:start position:0% +start looking for these chains you have +to construct them algorithmically + + align:start position:0% +to construct them algorithmically + + + align:start position:0% +to construct them algorithmically +and get you know as a result when it's + + align:start position:0% +and get you know as a result when it's + + + align:start position:0% +and get you know as a result when it's +true a statement about x and t + + align:start position:0% +true a statement about x and t + + + align:start position:0% +true a statement about x and t +indirectly revealed preferred and then + + align:start position:0% +indirectly revealed preferred and then + + + align:start position:0% +indirectly revealed preferred and then +in the same data set go looking for an + + align:start position:0% +in the same data set go looking for an + + + align:start position:0% +in the same data set go looking for an +instance where there was a direct + + align:start position:0% +instance where there was a direct + + + align:start position:0% +instance where there was a direct +comparison and it better be that the + + align:start position:0% +comparison and it better be that the + + + align:start position:0% +comparison and it better be that the +inequality is weakly going this + + align:start position:0% +inequality is weakly going this + + + align:start position:0% +inequality is weakly going this +direction so it's an algorithm i'm + + align:start position:0% +direction so it's an algorithm i'm + + + align:start position:0% +direction so it's an algorithm i'm +trying to say + + align:start position:0% +trying to say + + + align:start position:0% +trying to say +because again if it doesn't go in this + + align:start position:0% +because again if it doesn't go in this + + + align:start position:0% +because again if it doesn't go in this +direction then it kind of contradicts + + align:start position:0% +direction then it kind of contradicts + + + align:start position:0% +direction then it kind of contradicts +the whole notion of revealed preference + + align:start position:0% +the whole notion of revealed preference + + + align:start position:0% +the whole notion of revealed preference +and transitivity + + align:start position:0% +and transitivity + + + align:start position:0% +and transitivity +so + + align:start position:0% +so + + + align:start position:0% +so +again good news ironically + + align:start position:0% +again good news ironically + + + align:start position:0% +again good news ironically +we are potentially able to reject there + + align:start position:0% +we are potentially able to reject there + + + align:start position:0% +we are potentially able to reject there +are comparisons in the data which if if + + align:start position:0% +are comparisons in the data which if if + + + align:start position:0% +are comparisons in the data which if if +this inequality goes the other way would + + align:start position:0% +this inequality goes the other way would + + + align:start position:0% +this inequality goes the other way would +tell us there's no way that this data + + align:start position:0% +tell us there's no way that this data + + + align:start position:0% +tell us there's no way that this data +came from a rational maximizing consumer + + align:start position:0% +came from a rational maximizing consumer + + + align:start position:0% +came from a rational maximizing consumer +and that's good for us now it doesn't + + align:start position:0% +and that's good for us now it doesn't + + + align:start position:0% +and that's good for us now it doesn't +mean that in any given data set you will + + align:start position:0% +mean that in any given data set you will + + + align:start position:0% +mean that in any given data set you will +necessarily find a violation but you and + + align:start position:0% +necessarily find a violation but you and + + + align:start position:0% +necessarily find a violation but you and +you end up with a weak statement that + + align:start position:0% +you end up with a weak statement that + + + align:start position:0% +you end up with a weak statement that +the data set look as if there was + + align:start position:0% +the data set look as if there was + + + align:start position:0% +the data set look as if there was +nothing inconsistent in this data with + + align:start position:0% +nothing inconsistent in this data with + + + align:start position:0% +nothing inconsistent in this data with +respect to the statement that they came + + align:start position:0% +respect to the statement that they came + + + align:start position:0% +respect to the statement that they came +from a rational maximizing consumer + + align:start position:0% +from a rational maximizing consumer + + + align:start position:0% +from a rational maximizing consumer +so we should check and make sure that + + align:start position:0% +so we should check and make sure that + + + align:start position:0% +so we should check and make sure that +that's true + + align:start position:0% +that's true + + + align:start position:0% +that's true +so that's the spirit of it + + align:start position:0% +so that's the spirit of it + + + align:start position:0% +so that's the spirit of it +questions + + align:start position:0% +questions + + + align:start position:0% +questions +okay + + align:start position:0% +okay + + + align:start position:0% +okay +so let me get to the computational part + + align:start position:0% +so let me get to the computational part + + + align:start position:0% +so let me get to the computational part +these guys at caltech consumer theory + + align:start position:0% +these guys at caltech consumer theory + + + align:start position:0% +these guys at caltech consumer theory +assumes consumers possess infinite + + align:start position:0% +assumes consumers possess infinite + + + align:start position:0% +assumes consumers possess infinite +computational abilities like they can + + align:start position:0% +computational abilities like they can + + + align:start position:0% +computational abilities like they can +solve max problems and potentially hard + + align:start position:0% +solve max problems and potentially hard + + + align:start position:0% +solve max problems and potentially hard +problems proponents of bounded + + align:start position:0% +problems proponents of bounded + + + align:start position:0% +problems proponents of bounded +rationality want to require that any + + align:start position:0% +rationality want to require that any + + + align:start position:0% +rationality want to require that any +reasonable + + align:start position:0% +reasonable + + + align:start position:0% +reasonable +model of consumer behavior incorporate + + align:start position:0% +model of consumer behavior incorporate + + + align:start position:0% +model of consumer behavior incorporate +computational constraints + + align:start position:0% +computational constraints + + + align:start position:0% +computational constraints +in other words they may not be able to + + align:start position:0% +in other words they may not be able to + + + align:start position:0% +in other words they may not be able to +solve a hard problem + + align:start position:0% +solve a hard problem + + + align:start position:0% +solve a hard problem +they may choose something but it + + align:start position:0% +they may choose something but it + + + align:start position:0% +they may choose something but it +wouldn't be the full solution because + + align:start position:0% +wouldn't be the full solution because + + + align:start position:0% +wouldn't be the full solution because +they're not able to compute it + + align:start position:0% +they're not able to compute it + + + align:start position:0% +they're not able to compute it +and nichinike and his co-authors are + + align:start position:0% +and nichinike and his co-authors are + + + align:start position:0% +and nichinike and his co-authors are +saying that's false + + align:start position:0% +saying that's false + + + align:start position:0% +saying that's false +very much in the spirit of revealed + + align:start position:0% +very much in the spirit of revealed + + + align:start position:0% +very much in the spirit of revealed +preference any consumption data set that + + align:start position:0% +preference any consumption data set that + + + align:start position:0% +preference any consumption data set that +is compatible with a rational consumer + + align:start position:0% +is compatible with a rational consumer + + + align:start position:0% +is compatible with a rational consumer +excuse me it is also compatible with a + + align:start position:0% +excuse me it is also compatible with a + + + align:start position:0% +excuse me it is also compatible with a +rational and computationally bounded + + align:start position:0% +rational and computationally bounded + + + align:start position:0% +rational and computationally bounded +consumer that is to say the data set in + + align:start position:0% +consumer that is to say the data set in + + + align:start position:0% +consumer that is to say the data set in +hand + + align:start position:0% +hand + + + align:start position:0% +hand +can always be rationalized by a utility + + align:start position:0% +can always be rationalized by a utility + + + align:start position:0% +can always be rationalized by a utility +function that's pretty easy to solve + + align:start position:0% +function that's pretty easy to solve + + + align:start position:0% +function that's pretty easy to solve +meaning solved in polynomial time + + align:start position:0% +meaning solved in polynomial time + + + align:start position:0% +meaning solved in polynomial time +so this is very much like not being able + + align:start position:0% +so this is very much like not being able + + + align:start position:0% +so this is very much like not being able +to test the convexity of preferences + + align:start position:0% +to test the convexity of preferences + + + align:start position:0% +to test the convexity of preferences +you start with something non-convex but + + align:start position:0% +you start with something non-convex but + + + align:start position:0% +you start with something non-convex but +it generates a data set that could also + + align:start position:0% +it generates a data set that could also + + + align:start position:0% +it generates a data set that could also +be generated by something convex + + align:start position:0% +be generated by something convex + + + align:start position:0% +be generated by something convex +we start with something that could have + + align:start position:0% +we start with something that could have + + + align:start position:0% +we start with something that could have +come from + + align:start position:0% +come from + + + align:start position:0% +come from +the household solving a hard problem + + align:start position:0% +the household solving a hard problem + + + align:start position:0% +the household solving a hard problem +but it could also have come from a + + align:start position:0% +but it could also have come from a + + + align:start position:0% +but it could also have come from a +household solving a simpler problem + + align:start position:0% +household solving a simpler problem + + + align:start position:0% +household solving a simpler problem +i'm not giving you any intuition on this + + align:start position:0% +i'm not giving you any intuition on this + + + align:start position:0% +i'm not giving you any intuition on this +right now i'm telling you what these + + align:start position:0% +right now i'm telling you what these + + + align:start position:0% +right now i'm telling you what these +computer scientists have figured out and + + align:start position:0% +computer scientists have figured out and + + + align:start position:0% +computer scientists have figured out and +again their matrix + + align:start position:0% +again their matrix + + + align:start position:0% +again their matrix +their metric is how hard is it to solve + + align:start position:0% +their metric is how hard is it to solve + + + align:start position:0% +their metric is how hard is it to solve +the problem you know it's sort of + + align:start position:0% +the problem you know it's sort of + + + align:start position:0% +the problem you know it's sort of +looking at derivatives and so on how + + align:start position:0% +looking at derivatives and so on how + + + align:start position:0% +looking at derivatives and so on how +long does it take as we say increase the + + align:start position:0% +long does it take as we say increase the + + + align:start position:0% +long does it take as we say increase the +number of goods + + align:start position:0% +number of goods + + + align:start position:0% +number of goods +if it's exponential it's bad if it's + + align:start position:0% +if it's exponential it's bad if it's + + + align:start position:0% +if it's exponential it's bad if it's +polynomial it's good all right another + + align:start position:0% +polynomial it's good all right another + + + align:start position:0% +polynomial it's good all right another +version of this instead of having a + + align:start position:0% +version of this instead of having a + + + align:start position:0% +version of this instead of having a +single household maximizing or otherwise + + align:start position:0% +single household maximizing or otherwise + + + align:start position:0% +single household maximizing or otherwise +we have multiple agents interacting in a + + align:start position:0% +we have multiple agents interacting in a + + + align:start position:0% +we have multiple agents interacting in a +market economy we want to say + + align:start position:0% +market economy we want to say + + + align:start position:0% +market economy we want to say +if possible that the observed market + + align:start position:0% +if possible that the observed market + + + align:start position:0% +if possible that the observed market +outcomes are consistent not only with + + align:start position:0% +outcomes are consistent not only with + + + align:start position:0% +outcomes are consistent not only with +individual maximization but with a + + align:start position:0% +individual maximization but with a + + + align:start position:0% +individual maximization but with a +volrazian equilibrium + + align:start position:0% +volrazian equilibrium + + + align:start position:0% +volrazian equilibrium +so what is the empirical content is it + + align:start position:0% +so what is the empirical content is it + + + align:start position:0% +so what is the empirical content is it +really hard to solve the general + + align:start position:0% +really hard to solve the general + + + align:start position:0% +really hard to solve the general +equilibrium computationally in which + + align:start position:0% +equilibrium computationally in which + + + align:start position:0% +equilibrium computationally in which +case + + align:start position:0% +case + + + align:start position:0% +case +it's not likely we're going to be able + + align:start position:0% +it's not likely we're going to be able + + + align:start position:0% +it's not likely we're going to be able +to accept in the data that it came from + + align:start position:0% +to accept in the data that it came from + + + align:start position:0% +to accept in the data that it came from +the underlying economy or it's a version + + align:start position:0% +the underlying economy or it's a version + + + align:start position:0% +the underlying economy or it's a version +of the individual maximization problem + + align:start position:0% +of the individual maximization problem + + + align:start position:0% +of the individual maximization problem +that there's another economy which is + + align:start position:0% +that there's another economy which is + + + align:start position:0% +that there's another economy which is +actually easy easier to solve that could + + align:start position:0% +actually easy easier to solve that could + + + align:start position:0% +actually easy easier to solve that could +have generated the same data + + align:start position:0% +have generated the same data + + + align:start position:0% +have generated the same data +this is totally remarkable stuff + + align:start position:0% +this is totally remarkable stuff + + + align:start position:0% +this is totally remarkable stuff +because it goes against the grain of the + + align:start position:0% +because it goes against the grain of the + + + align:start position:0% +because it goes against the grain of the +way one would like to think about it a + + align:start position:0% +way one would like to think about it a + + + align:start position:0% +way one would like to think about it a +rational as rational as consumers can + + align:start position:0% +rational as rational as consumers can + + + align:start position:0% +rational as rational as consumers can +possibly be + + align:start position:0% +possibly be + + + align:start position:0% +possibly be +it's unlikely they can solve in their + + align:start position:0% +it's unlikely they can solve in their + + + align:start position:0% +it's unlikely they can solve in their +minds problems that prove intractable + + align:start position:0% +minds problems that prove intractable + + + align:start position:0% +minds problems that prove intractable +for computer scientists equipped with + + align:start position:0% +for computer scientists equipped with + + + align:start position:0% +for computer scientists equipped with +the latest technology it's a cool + + align:start position:0% +the latest technology it's a cool + + + align:start position:0% +the latest technology it's a cool +statement these are really famous + + align:start position:0% +statement these are really famous + + + align:start position:0% +statement these are really famous +theorists by the way + + align:start position:0% +theorists by the way + + + align:start position:0% +theorists by the way +gilboa schmeidler and possibly + + align:start position:0% +gilboa schmeidler and possibly + + + align:start position:0% +gilboa schmeidler and possibly +solve in their minds get it + + align:start position:0% +solve in their minds get it + + + align:start position:0% +solve in their minds get it +the way what you would need for a you + + align:start position:0% +the way what you would need for a you + + + align:start position:0% +the way what you would need for a you +know a supercomputer + + align:start position:0% +know a supercomputer + + + align:start position:0% +know a supercomputer +if an equilibrium is not efficiently + + align:start position:0% +if an equilibrium is not efficiently + + + align:start position:0% +if an equilibrium is not efficiently +computed this is the market version + + align:start position:0% +computed this is the market version + + + align:start position:0% +computed this is the market version +much of the credibility of using the + + align:start position:0% +much of the credibility of using the + + + align:start position:0% +much of the credibility of using the +predicate that we have rational agents + + align:start position:0% +predicate that we have rational agents + + + align:start position:0% +predicate that we have rational agents +is lost and a shorthand version of that + + align:start position:0% +is lost and a shorthand version of that + + + align:start position:0% +is lost and a shorthand version of that +if your laptop can't find it neither can + + align:start position:0% +if your laptop can't find it neither can + + + align:start position:0% +if your laptop can't find it neither can +the market but these guys are saying + + align:start position:0% +the market but these guys are saying + + + align:start position:0% +the market but these guys are saying +that's just wrong it's just completely + + align:start position:0% +that's just wrong it's just completely + + + align:start position:0% +that's just wrong it's just completely +wrong + + align:start position:0% +wrong + + + align:start position:0% +wrong +because they misunderstand the role of + + align:start position:0% +because they misunderstand the role of + + + align:start position:0% +because they misunderstand the role of +models in economics which is as if the + + align:start position:0% +models in economics which is as if the + + + align:start position:0% +models in economics which is as if the +model were a reality + + align:start position:0% +model were a reality + + + align:start position:0% +model were a reality +then there are restrictions on data it + + align:start position:0% +then there are restrictions on data it + + + align:start position:0% +then there are restrictions on data it +is not a statement that we have all of + + align:start position:0% +is not a statement that we have all of + + + align:start position:0% +is not a statement that we have all of +the reality captured in the model + + align:start position:0% +the reality captured in the model + + + align:start position:0% +the reality captured in the model +so + + align:start position:0% +so + + + align:start position:0% +so +reality behaves as if the theory were + + align:start position:0% +reality behaves as if the theory were + + + align:start position:0% +reality behaves as if the theory were +true + + align:start position:0% +true + + + align:start position:0% +true +a consumption data set + + align:start position:0% +a consumption data set + + + align:start position:0% +a consumption data set +is either not rationalizable at all so + + align:start position:0% +is either not rationalizable at all so + + + align:start position:0% +is either not rationalizable at all so +that's the rejection part they're not + + align:start position:0% +that's the rejection part they're not + + + align:start position:0% +that's the rejection part they're not +going to overturn that there's still + + align:start position:0% +going to overturn that there's still + + + align:start position:0% +going to overturn that there's still +content it's either not rationalizable + + align:start position:0% +content it's either not rationalizable + + + align:start position:0% +content it's either not rationalizable +at all or + + align:start position:0% +at all or + + + align:start position:0% +at all or +it's rationalizable by a utility + + align:start position:0% +it's rationalizable by a utility + + + align:start position:0% +it's rationalizable by a utility +function that's fairly easy to maximize + + align:start position:0% +function that's fairly easy to maximize + + + align:start position:0% +function that's fairly easy to maximize +when i show you these slides i kind of + + align:start position:0% +when i show you these slides i kind of + + + align:start position:0% +when i show you these slides i kind of +want to show you more but i guess we + + align:start position:0% +want to show you more but i guess we + + + align:start position:0% +want to show you more but i guess we +have limited time so i probably should + + align:start position:0% +have limited time so i probably should + + + align:start position:0% +have limited time so i probably should +have put this paper on the reading list + + align:start position:0% +have put this paper on the reading list + + + align:start position:0% +have put this paper on the reading list +as optional + + align:start position:0% +as optional + + + align:start position:0% +as optional +okay so let's go to general equilibrium + + align:start position:0% +okay so let's go to general equilibrium + + + align:start position:0% +okay so let's go to general equilibrium +in a paper of brown and matskin which + + align:start position:0% +in a paper of brown and matskin which + + + align:start position:0% +in a paper of brown and matskin which +all things considered relatively recent + + align:start position:0% +all things considered relatively recent + + + align:start position:0% +all things considered relatively recent +suppose we're given data set on a number + + align:start position:0% +suppose we're given data set on a number + + + align:start position:0% +suppose we're given data set on a number +of households capital i in the economy + + align:start position:0% +of households capital i in the economy + + + align:start position:0% +of households capital i in the economy +and we see their individual endowments + + align:start position:0% +and we see their individual endowments + + + align:start position:0% +and we see their individual endowments +private ownership economy + + align:start position:0% +private ownership economy + + + align:start position:0% +private ownership economy +omega i across households capital i + + align:start position:0% +omega i across households capital i + + + align:start position:0% +omega i across households capital i +then there's something + + align:start position:0% +then there's something + + + align:start position:0% +then there's something +that i'll elaborate in words now called + + align:start position:0% +that i'll elaborate in words now called + + + align:start position:0% +that i'll elaborate in words now called +anything goes + + align:start position:0% +anything goes + + + align:start position:0% +anything goes +general equilibrium theory does not put + + align:start position:0% +general equilibrium theory does not put + + + align:start position:0% +general equilibrium theory does not put +restrictions on data anything goes now + + align:start position:0% +restrictions on data anything goes now + + + align:start position:0% +restrictions on data anything goes now +and that was a killer that kind of + + align:start position:0% +and that was a killer that kind of + + + align:start position:0% +and that was a killer that kind of +killed the whole subject for a long time + + align:start position:0% +killed the whole subject for a long time + + + align:start position:0% +killed the whole subject for a long time +because of what i'm saying + + align:start position:0% +because of what i'm saying + + + align:start position:0% +because of what i'm saying +now + + align:start position:0% +now + + + align:start position:0% +now +the object in question was the our + + align:start position:0% +the object in question was the our + + + align:start position:0% +the object in question was the our +famous excess demand function that we + + align:start position:0% +famous excess demand function that we + + + align:start position:0% +famous excess demand function that we +have used before the aggregate demand + + align:start position:0% +have used before the aggregate demand + + + align:start position:0% +have used before the aggregate demand +function + + align:start position:0% +function + + + align:start position:0% +function +that we've been focusing on with + + align:start position:0% +that we've been focusing on with + + + align:start position:0% +that we've been focusing on with +aggregation and so on + + align:start position:0% +aggregation and so on + + + align:start position:0% +aggregation and so on +what shape does that aggregate demand + + align:start position:0% +what shape does that aggregate demand + + + align:start position:0% +what shape does that aggregate demand +function have as we vary prices + + align:start position:0% +function have as we vary prices + + + align:start position:0% +function have as we vary prices +and the answer was whatever wiggle and + + align:start position:0% +and the answer was whatever wiggle and + + + align:start position:0% +and the answer was whatever wiggle and +turn it has including upsloping forces + + align:start position:0% +turn it has including upsloping forces + + + align:start position:0% +turn it has including upsloping forces +and portions and so on you can always + + align:start position:0% +and portions and so on you can always + + + align:start position:0% +and portions and so on you can always +find an underlying economy that would + + align:start position:0% +find an underlying economy that would + + + align:start position:0% +find an underlying economy that would +have generated that excess demand + + align:start position:0% +have generated that excess demand + + + align:start position:0% +have generated that excess demand +so this part of it is the seeming answer + + align:start position:0% +so this part of it is the seeming answer + + + align:start position:0% +so this part of it is the seeming answer +to the question what happens if we don't + + align:start position:0% +to the question what happens if we don't + + + align:start position:0% +to the question what happens if we don't +put any restrictions on utility + + align:start position:0% +put any restrictions on utility + + + align:start position:0% +put any restrictions on utility +functions other than you know things + + align:start position:0% +functions other than you know things + + + align:start position:0% +functions other than you know things +like rationality and the answer is + + align:start position:0% +like rationality and the answer is + + + align:start position:0% +like rationality and the answer is +anything could happen + + align:start position:0% +anything could happen + + + align:start position:0% +anything could happen +that aggregate demand function could + + align:start position:0% +that aggregate demand function could + + + align:start position:0% +that aggregate demand function could +look any way you want it to for any + + align:start position:0% +look any way you want it to for any + + + align:start position:0% +look any way you want it to for any +aggregate demand function we can + + align:start position:0% +aggregate demand function we can + + + align:start position:0% +aggregate demand function we can +populate an economy with a finite number + + align:start position:0% +populate an economy with a finite number + + + align:start position:0% +populate an economy with a finite number +of households give them certain + + align:start position:0% +of households give them certain + + + align:start position:0% +of households give them certain +preferences + + align:start position:0% +preferences + + + align:start position:0% +preferences +and ownership of resources in such a way + + align:start position:0% +and ownership of resources in such a way + + + align:start position:0% +and ownership of resources in such a way +we can get that aggregate demand to + + align:start position:0% +we can get that aggregate demand to + + + align:start position:0% +we can get that aggregate demand to +shift and turn and and do whatever we + + align:start position:0% +shift and turn and and do whatever we + + + align:start position:0% +shift and turn and and do whatever we +want so again + + align:start position:0% +want so again + + + align:start position:0% +want so again +the shorthand is anything goes and + + align:start position:0% +the shorthand is anything goes and + + + align:start position:0% +the shorthand is anything goes and +because we could never reject the model + + align:start position:0% +because we could never reject the model + + + align:start position:0% +because we could never reject the model +people thought that general equilibrium + + align:start position:0% +people thought that general equilibrium + + + align:start position:0% +people thought that general equilibrium +had no content and they stopped doing it + + align:start position:0% +had no content and they stopped doing it + + + align:start position:0% +had no content and they stopped doing it +it's kind of discredited + + align:start position:0% +it's kind of discredited + + + align:start position:0% +it's kind of discredited +this was not just one person it was hugo + + align:start position:0% +this was not just one person it was hugo + + + align:start position:0% +this was not just one person it was hugo +sun and sean debrew and montel + + align:start position:0% +sun and sean debrew and montel + + + align:start position:0% +sun and sean debrew and montel +okay + + align:start position:0% +okay + + + align:start position:0% +okay +but let's just change this a bit + + align:start position:0% +but let's just change this a bit + + + align:start position:0% +but let's just change this a bit +first what is this seemingly reasonable + + align:start position:0% +first what is this seemingly reasonable + + + align:start position:0% +first what is this seemingly reasonable +but actually crazy thing that we + + align:start position:0% +but actually crazy thing that we + + + align:start position:0% +but actually crazy thing that we +actually see the excess demand we never + + align:start position:0% +actually see the excess demand we never + + + align:start position:0% +actually see the excess demand we never +see that + + align:start position:0% +see that + + + align:start position:0% +see that +if we see market economy we only see + + align:start position:0% +if we see market economy we only see + + + align:start position:0% +if we see market economy we only see +market clearing prices we don't see what + + align:start position:0% +market clearing prices we don't see what + + + align:start position:0% +market clearing prices we don't see what +happens out of out of equilibrium + + align:start position:0% +happens out of out of equilibrium + + + align:start position:0% +happens out of out of equilibrium +so we only see where it crosses we see + + align:start position:0% +so we only see where it crosses we see + + + align:start position:0% +so we only see where it crosses we see +the fixed points + + align:start position:0% +the fixed points + + + align:start position:0% +the fixed points +okay + + align:start position:0% +okay + + + align:start position:0% +okay +well let's give us a little more data + + align:start position:0% +well let's give us a little more data + + + align:start position:0% +well let's give us a little more data +then + + align:start position:0% +then + + + align:start position:0% +then +given a set of observations on prices + + align:start position:0% +given a set of observations on prices + + + align:start position:0% +given a set of observations on prices +and individual endowments does there + + align:start position:0% +and individual endowments does there + + + align:start position:0% +and individual endowments does there +exist + + align:start position:0% +exist + + + align:start position:0% +exist +okay so t now indicates the economy + + align:start position:0% +okay so t now indicates the economy + + + align:start position:0% +okay so t now indicates the economy +it's as if we're going to go in the + + align:start position:0% +it's as if we're going to go in the + + + align:start position:0% +it's as if we're going to go in the +cross section across several or many + + align:start position:0% +cross section across several or many + + + align:start position:0% +cross section across several or many +economies that vary in the individual + + align:start position:0% +economies that vary in the individual + + + align:start position:0% +economies that vary in the individual +ownership of endowments so it's omega i + + align:start position:0% +ownership of endowments so it's omega i + + + align:start position:0% +ownership of endowments so it's omega i +t for the teeth economy observation for + + align:start position:0% +t for the teeth economy observation for + + + align:start position:0% +t for the teeth economy observation for +any t it varies over i we have a finite + + align:start position:0% +any t it varies over i we have a finite + + + align:start position:0% +any t it varies over i we have a finite +number of households but t is varying in + + align:start position:0% +number of households but t is varying in + + + align:start position:0% +number of households but t is varying in +the sample that's the number of + + align:start position:0% +the sample that's the number of + + + align:start position:0% +the sample that's the number of +economies in the sample those economies + + align:start position:0% +economies in the sample those economies + + + align:start position:0% +economies in the sample those economies +are all alike for preferences that's + + align:start position:0% +are all alike for preferences that's + + + align:start position:0% +are all alike for preferences that's +assumed + + align:start position:0% +assumed + + + align:start position:0% +assumed +but they differ in the ownership + + align:start position:0% +but they differ in the ownership + + + align:start position:0% +but they differ in the ownership +structure + + align:start position:0% +structure + + + align:start position:0% +structure +the omega it's + + align:start position:0% +the omega it's + + + align:start position:0% +the omega it's +so then does there exist a + + align:start position:0% +so then does there exist a + + + align:start position:0% +so then does there exist a +sequence of these economies with + + align:start position:0% +sequence of these economies with + + + align:start position:0% +sequence of these economies with +each with its associated aggregate + + align:start position:0% +each with its associated aggregate + + + align:start position:0% +each with its associated aggregate +excess demand + + align:start position:0% +excess demand + + + align:start position:0% +excess demand +but such that those prices that we see + + align:start position:0% +but such that those prices that we see + + + align:start position:0% +but such that those prices that we see +stuck into the aggregated excess demand + + align:start position:0% +stuck into the aggregated excess demand + + + align:start position:0% +stuck into the aggregated excess demand +equals zero this last statement is just + + align:start position:0% +equals zero this last statement is just + + + align:start position:0% +equals zero this last statement is just +a statement that + + align:start position:0% +a statement that + + + align:start position:0% +a statement that +that the prices come from the market in + + align:start position:0% +that the prices come from the market in + + + align:start position:0% +that the prices come from the market in +other words the data set we're going to + + align:start position:0% +other words the data set we're going to + + + align:start position:0% +other words the data set we're going to +see + + align:start position:0% +see + + + align:start position:0% +see +would be the prices + + align:start position:0% +would be the prices + + + align:start position:0% +would be the prices +that because it's a market are + + align:start position:0% +that because it's a market are + + + align:start position:0% +that because it's a market are +associated with with zero excess demand + + align:start position:0% +associated with with zero excess demand + + + align:start position:0% +associated with with zero excess demand +equilibrium prices + + align:start position:0% +equilibrium prices + + + align:start position:0% +equilibrium prices +so we're going to see equilibrium prices + + align:start position:0% +so we're going to see equilibrium prices + + + align:start position:0% +so we're going to see equilibrium prices +and we're also going to + + align:start position:0% +and we're also going to + + + align:start position:0% +and we're also going to +see individual endowments + + align:start position:0% +see individual endowments + + + align:start position:0% +see individual endowments +assuming preferences are all the same + + align:start position:0% +assuming preferences are all the same + + + align:start position:0% +assuming preferences are all the same +okay so i'll give you the the punch line + + align:start position:0% +okay so i'll give you the the punch line + + + align:start position:0% +okay so i'll give you the the punch line +that's brown and mask and + + align:start position:0% +that's brown and mask and + + + align:start position:0% +that's brown and mask and +the punch line is going to be + + align:start position:0% +the punch line is going to be + + + align:start position:0% +the punch line is going to be +what we've been saying throughout the + + align:start position:0% +what we've been saying throughout the + + + align:start position:0% +what we've been saying throughout the +lecture today + + align:start position:0% +lecture today + + + align:start position:0% +lecture today +namely if we're given data like this we + + align:start position:0% +namely if we're given data like this we + + + align:start position:0% +namely if we're given data like this we +can actually reject that the data could + + align:start position:0% +can actually reject that the data could + + + align:start position:0% +can actually reject that the data could +have come + + align:start position:0% +have come + + + align:start position:0% +have come +as a market equilibrium that is to say + + align:start position:0% +as a market equilibrium that is to say + + + align:start position:0% +as a market equilibrium that is to say +that the market the data couldn't + + align:start position:0% +that the market the data couldn't + + + align:start position:0% +that the market the data couldn't +potentially never have come from + + align:start position:0% +potentially never have come from + + + align:start position:0% +potentially never have come from +individual household maximization + + align:start position:0% +individual household maximization + + + align:start position:0% +individual household maximization +and market clearing so it has content + + align:start position:0% +and market clearing so it has content + + + align:start position:0% +and market clearing so it has content +here's the differentiable version of it + + align:start position:0% +here's the differentiable version of it + + + align:start position:0% +here's the differentiable version of it +as abstract as general equilibrium + + align:start position:0% +as abstract as general equilibrium + + + align:start position:0% +as abstract as general equilibrium +theory is the sononshine debrew montel + + align:start position:0% +theory is the sononshine debrew montel + + + align:start position:0% +theory is the sononshine debrew montel +is overturned they're applying it to an + + align:start position:0% +is overturned they're applying it to an + + + align:start position:0% +is overturned they're applying it to an +exchange economy where we see prices and + + align:start position:0% +exchange economy where we see prices and + + + align:start position:0% +exchange economy where we see prices and +endowments they derive necessary and + + align:start position:0% +endowments they derive necessary and + + + align:start position:0% +endowments they derive necessary and +sufficient conditions for the + + align:start position:0% +sufficient conditions for the + + + align:start position:0% +sufficient conditions for the +equilibrium prices as a function of + + align:start position:0% +equilibrium prices as a function of + + + align:start position:0% +equilibrium prices as a function of +initial endowments and in their language + + align:start position:0% +initial endowments and in their language + + + align:start position:0% +initial endowments and in their language +they show that the economy can be + + align:start position:0% +they show that the economy can be + + + align:start position:0% +they show that the economy can be +generically + + align:start position:0% +generically + + + align:start position:0% +generically +identified what they mean by that is + + align:start position:0% +identified what they mean by that is + + + align:start position:0% +identified what they mean by that is +there is an underlying economy that + + align:start position:0% +there is an underlying economy that + + + align:start position:0% +there is an underlying economy that +would have generated the data + + align:start position:0% +would have generated the data + + + align:start position:0% +would have generated the data +but also + + align:start position:0% +but also + + + align:start position:0% +but also +that in principle one could have not + + align:start position:0% +that in principle one could have not + + + align:start position:0% +that in principle one could have not +been able to find such an economy and + + align:start position:0% +been able to find such an economy and + + + align:start position:0% +been able to find such an economy and +then sort of summarize where we are + + align:start position:0% +then sort of summarize where we are + + + align:start position:0% +then sort of summarize where we are +if you only had aggregate data you're + + align:start position:0% +if you only had aggregate data you're + + + align:start position:0% +if you only had aggregate data you're +sunk you're never going to get + + align:start position:0% +sunk you're never going to get + + + align:start position:0% +sunk you're never going to get +sufficients that allow you conditions + + align:start position:0% +sufficients that allow you conditions + + + align:start position:0% +sufficients that allow you conditions +that allow you to reject + + align:start position:0% +that allow you to reject + + + align:start position:0% +that allow you to reject +but when you have individual data + + align:start position:0% +but when you have individual data + + + align:start position:0% +but when you have individual data +you can get testable restrictions + + align:start position:0% +you can get testable restrictions + + + align:start position:0% +you can get testable restrictions +and bring back the content of general + + align:start position:0% +and bring back the content of general + + + align:start position:0% +and bring back the content of general +equilibrium theory + + align:start position:0% +equilibrium theory + + + align:start position:0% +equilibrium theory +so again this kind of summarizes my + + align:start position:0% +so again this kind of summarizes my + + + align:start position:0% +so again this kind of summarizes my +deliberately provocative statement that + + align:start position:0% +deliberately provocative statement that + + + align:start position:0% +deliberately provocative statement that +you need microdata to do macro + + align:start position:0% +you need microdata to do macro + + + align:start position:0% +you need microdata to do macro +and then they go on to talk about + + align:start position:0% +and then they go on to talk about + + + align:start position:0% +and then they go on to talk about +something you're familiar with because + + align:start position:0% +something you're familiar with because + + + align:start position:0% +something you're familiar with because +we did it in the class + + align:start position:0% +we did it in the class + + + align:start position:0% +we did it in the class +we're sharing in indian villages + + align:start position:0% +we're sharing in indian villages + + + align:start position:0% +we're sharing in indian villages +it's not uncommon to observe endowments + + align:start position:0% +it's not uncommon to observe endowments + + + align:start position:0% +it's not uncommon to observe endowments +like crops and prices we did a little + + align:start position:0% +like crops and prices we did a little + + + align:start position:0% +like crops and prices we did a little +bit of that and less so with the risk + + align:start position:0% +bit of that and less so with the risk + + + align:start position:0% +bit of that and less so with the risk +sharing in which case their + + align:start position:0% +sharing in which case their + + + align:start position:0% +sharing in which case their +content works directly + + align:start position:0% +content works directly + + + align:start position:0% +content works directly +if you really believed you were going + + align:start position:0% +if you really believed you were going + + + align:start position:0% +if you really believed you were going +from one village to another each were + + align:start position:0% +from one village to another each were + + + align:start position:0% +from one village to another each were +self-contained they had the same + + align:start position:0% +self-contained they had the same + + + align:start position:0% +self-contained they had the same +preferences and the premise would be + + align:start position:0% +preferences and the premise would be + + + align:start position:0% +preferences and the premise would be +we're seeing market outcomes then their + + align:start position:0% +we're seeing market outcomes then their + + + align:start position:0% +we're seeing market outcomes then their +theory applies directly you can even go + + align:start position:0% +theory applies directly you can even go + + + align:start position:0% +theory applies directly you can even go +to large economies not villages and + + align:start position:0% +to large economies not villages and + + + align:start position:0% +to large economies not villages and +think about + + align:start position:0% +think about + + + align:start position:0% +think about +types of individuals finite number of + + align:start position:0% +types of individuals finite number of + + + align:start position:0% +types of individuals finite number of +types but a large number of individuals + + align:start position:0% +types but a large number of individuals + + + align:start position:0% +types but a large number of individuals +of a given type + + align:start position:0% +of a given type + + + align:start position:0% +of a given type +and again you can use their artillery + + align:start position:0% +and again you can use their artillery + + + align:start position:0% +and again you can use their artillery +now interestingly lest you think + + align:start position:0% +now interestingly lest you think + + + align:start position:0% +now interestingly lest you think +economists have this all figured out + + align:start position:0% +economists have this all figured out + + + align:start position:0% +economists have this all figured out +an interesting question is how to extend + + align:start position:0% +an interesting question is how to extend + + + align:start position:0% +an interesting question is how to extend +this to production + + align:start position:0% +this to production + + + align:start position:0% +this to production +they refer to + + align:start position:0% +they refer to + + + align:start position:0% +they refer to +changes in factor endowments which have + + align:start position:0% +changes in factor endowments which have + + + align:start position:0% +changes in factor endowments which have +observable impact on factor prices so + + align:start position:0% +observable impact on factor prices so + + + align:start position:0% +observable impact on factor prices so +that's an allusion to the trade lectures + + align:start position:0% +that's an allusion to the trade lectures + + + align:start position:0% +that's an allusion to the trade lectures +we did + + align:start position:0% +we did + + + align:start position:0% +we did +and they haven't figured it out yet they + + align:start position:0% +and they haven't figured it out yet they + + + align:start position:0% +and they haven't figured it out yet they +haven't figured out + + align:start position:0% +haven't figured out + + + align:start position:0% +haven't figured out +whether you know there are rejectable + + align:start position:0% +whether you know there are rejectable + + + align:start position:0% +whether you know there are rejectable +restrictions remember when we did the + + align:start position:0% +restrictions remember when we did the + + + align:start position:0% +restrictions remember when we did the +model + + align:start position:0% +model + + + align:start position:0% +model +the two by two case we had constant + + align:start position:0% +the two by two case we had constant + + + align:start position:0% +the two by two case we had constant +returns to scale and a few other + + align:start position:0% +returns to scale and a few other + + + align:start position:0% +returns to scale and a few other +assumptions + + align:start position:0% +assumptions + + + align:start position:0% +assumptions +so they're saying like drop all + + align:start position:0% +so they're saying like drop all + + + align:start position:0% +so they're saying like drop all +assumptions + + align:start position:0% +assumptions + + + align:start position:0% +assumptions +can we could we put restrictions on data + + align:start position:0% +can we could we put restrictions on data + + + align:start position:0% +can we could we put restrictions on data +and say we'd never + + align:start position:0% +and say we'd never + + + align:start position:0% +and say we'd never +see in the co you know + + align:start position:0% +see in the co you know + + + align:start position:0% +see in the co you know +violations of some kind and they haven't + + align:start position:0% +violations of some kind and they haven't + + + align:start position:0% +violations of some kind and they haven't +figured it out + + align:start position:0% +figured it out + + + align:start position:0% +figured it out +so we're on the research frontier at + + align:start position:0% +so we're on the research frontier at + + + align:start position:0% +so we're on the research frontier at +this point + + align:start position:0% +this point + + + align:start position:0% +this point +okay so that's + + align:start position:0% +okay so that's + + + align:start position:0% +okay so that's +what i have for today + + align:start position:0% +what i have for today + + + align:start position:0% +what i have for today +again very much part and parcel of the + + align:start position:0% +again very much part and parcel of the + + + align:start position:0% +again very much part and parcel of the +whole spirit of the class which is to + + align:start position:0% +whole spirit of the class which is to + + + align:start position:0% +whole spirit of the class which is to +think about + + align:start position:0% +think about + + + align:start position:0% +think about +economists as running experiments + + align:start position:0% +economists as running experiments + + + align:start position:0% +economists as running experiments +and you saw three of them today + + align:start position:0% + + + + align:start position:0% + +you \ No newline at end of file diff --git a/s-QcRrGppsk.txt b/s-QcRrGppsk.txt new file mode 100644 index 0000000000000000000000000000000000000000..971e8a4d162240381fdef26ea95158a687048c7b --- /dev/null +++ b/s-QcRrGppsk.txt @@ -0,0 +1,2163 @@ +align:start position:0% + +welcome back to 8701 + + align:start position:0% +welcome back to 8701 + + + align:start position:0% +welcome back to 8701 +so the name of this class is called + + align:start position:0% +so the name of this class is called + + + align:start position:0% +so the name of this class is called +cardiomystic but what we're actually + + align:start position:0% +cardiomystic but what we're actually + + + align:start position:0% +cardiomystic but what we're actually +going to do + + align:start position:0% +going to do + + + align:start position:0% +going to do +is we're going to evaluate or learn how + + align:start position:0% +is we're going to evaluate or learn how + + + align:start position:0% +is we're going to evaluate or learn how +to deal with spin information + + align:start position:0% +to deal with spin information + + + align:start position:0% +to deal with spin information +in the calculation of our matrix + + align:start position:0% +in the calculation of our matrix + + + align:start position:0% +in the calculation of our matrix +elements + + align:start position:0% +elements + + + align:start position:0% +elements +so now what what is it what we're trying + + align:start position:0% +so now what what is it what we're trying + + + align:start position:0% +so now what what is it what we're trying +to do so the first + + align:start position:0% +to do so the first + + + align:start position:0% +to do so the first +problem we might have is that we have + + align:start position:0% +problem we might have is that we have + + + align:start position:0% +problem we might have is that we have +polarized particles + + align:start position:0% +polarized particles + + + align:start position:0% +polarized particles +so we have here again our example of + + align:start position:0% +so we have here again our example of + + + align:start position:0% +so we have here again our example of +electron neuron scattering + + align:start position:0% +electron neuron scattering + + + align:start position:0% +electron neuron scattering +and if you assume that the electron and + + align:start position:0% +and if you assume that the electron and + + + align:start position:0% +and if you assume that the electron and +the neurons are polarized + + align:start position:0% +the neurons are polarized + + + align:start position:0% +the neurons are polarized +you you will find as we discussed in the + + align:start position:0% +you you will find as we discussed in the + + + align:start position:0% +you you will find as we discussed in the +previous lecture + + align:start position:0% +previous lecture + + + align:start position:0% +previous lecture +that our matrix element is proportional + + align:start position:0% +that our matrix element is proportional + + + align:start position:0% +that our matrix element is proportional +to + + align:start position:0% +to + + + align:start position:0% +to +the joint vector of u1 times + + align:start position:0% +the joint vector of u1 times + + + align:start position:0% +the joint vector of u1 times +some sort of gamma matrix times the + + align:start position:0% +some sort of gamma matrix times the + + + align:start position:0% +some sort of gamma matrix times the +sphenoid and we probably have a + + align:start position:0% +sphenoid and we probably have a + + + align:start position:0% +sphenoid and we probably have a +polarization vector as well included + + align:start position:0% +polarization vector as well included + + + align:start position:0% +polarization vector as well included +here to give the polarization of the + + align:start position:0% +here to give the polarization of the + + + align:start position:0% +here to give the polarization of the +photon involved in + + align:start position:0% +photon involved in + + + align:start position:0% +photon involved in +in the um as a propagation good + + align:start position:0% +in the um as a propagation good + + + align:start position:0% +in the um as a propagation good +now in order to now get a number for m + + align:start position:0% +now in order to now get a number for m + + + align:start position:0% +now in order to now get a number for m +we actually have to be explicit + + align:start position:0% +we actually have to be explicit + + + align:start position:0% +we actually have to be explicit +about um the wave function of the + + align:start position:0% +about um the wave function of the + + + align:start position:0% +about um the wave function of the +external particles and you can do this + + align:start position:0% +external particles and you can do this + + + align:start position:0% +external particles and you can do this +you can just write this down + + align:start position:0% +you can just write this down + + + align:start position:0% +you can just write this down +however in experiments we are often + + align:start position:0% +however in experiments we are often + + + align:start position:0% +however in experiments we are often +interested in the scattering of + + align:start position:0% +interested in the scattering of + + + align:start position:0% +interested in the scattering of +unpolarized particles + + align:start position:0% +unpolarized particles + + + align:start position:0% +unpolarized particles +um you know even if you have a way to + + align:start position:0% +um you know even if you have a way to + + + align:start position:0% +um you know even if you have a way to +polarize a beam + + align:start position:0% +polarize a beam + + + align:start position:0% +polarize a beam +your polarization is not going to be + + align:start position:0% +your polarization is not going to be + + + align:start position:0% +your polarization is not going to be +perfect so in your calculation you might + + align:start position:0% +perfect so in your calculation you might + + + align:start position:0% +perfect so in your calculation you might +want to + + align:start position:0% +want to + + + align:start position:0% +want to +you know average or + + align:start position:0% +you know average or + + + align:start position:0% +you know average or +thumb over the available spins of your + + align:start position:0% +thumb over the available spins of your + + + align:start position:0% +thumb over the available spins of your +particle + + align:start position:0% +particle + + + align:start position:0% +particle +so now how how are we going to do this + + align:start position:0% +so now how how are we going to do this + + + align:start position:0% +so now how how are we going to do this +um so we're trying to calculate the spin + + align:start position:0% +um so we're trying to calculate the spin + + + align:start position:0% +um so we're trying to calculate the spin +averaged amplitude why averaging + + align:start position:0% +averaged amplitude why averaging + + + align:start position:0% +averaged amplitude why averaging +um we want to average over the + + align:start position:0% +um we want to average over the + + + align:start position:0% +um we want to average over the +polarization of the incoming particles + + align:start position:0% +polarization of the incoming particles + + + align:start position:0% +polarization of the incoming particles +again because we don't know what the + + align:start position:0% +again because we don't know what the + + + align:start position:0% +again because we don't know what the +polarization states + + align:start position:0% +polarization states + + + align:start position:0% +polarization states +are and we want to sum over the + + align:start position:0% +are and we want to sum over the + + + align:start position:0% +are and we want to sum over the +polarization of all final state + + align:start position:0% +polarization of all final state + + + align:start position:0% +polarization of all final state +particles + + align:start position:0% +particles + + + align:start position:0% +particles +simply because you know each + + align:start position:0% +simply because you know each + + + align:start position:0% +simply because you know each +polarization state is a possible outcome + + align:start position:0% +polarization state is a possible outcome + + + align:start position:0% +polarization state is a possible outcome +of the interaction and we have to sum + + align:start position:0% +of the interaction and we have to sum + + + align:start position:0% +of the interaction and we have to sum +over all possible outcomes good + + align:start position:0% +over all possible outcomes good + + + align:start position:0% +over all possible outcomes good +um so how do we calculate the spin + + align:start position:0% +um so how do we calculate the spin + + + align:start position:0% +um so how do we calculate the spin +average amplitude + + align:start position:0% +average amplitude + + + align:start position:0% +average amplitude +so again we start from our matrix + + align:start position:0% +so again we start from our matrix + + + align:start position:0% +so again we start from our matrix +element + + align:start position:0% +element + + + align:start position:0% +element +where we have the joint vector some + + align:start position:0% +where we have the joint vector some + + + align:start position:0% +where we have the joint vector some +gamma matrix and + + align:start position:0% +gamma matrix and + + + align:start position:0% +gamma matrix and +our sphenoid um if we then calculate the + + align:start position:0% +our sphenoid um if we then calculate the + + + align:start position:0% +our sphenoid um if we then calculate the +square + + align:start position:0% +square + + + align:start position:0% +square +of this matrix we find this solution + + align:start position:0% +of this matrix we find this solution + + + align:start position:0% +of this matrix we find this solution +here + + align:start position:0% +here + + + align:start position:0% +here +great and now we're just doing a few + + align:start position:0% +great and now we're just doing a few + + + align:start position:0% +great and now we're just doing a few +tricks um + + align:start position:0% +tricks um + + + align:start position:0% +tricks um +so first of all we can write our joint + + align:start position:0% +so first of all we can write our joint + + + align:start position:0% +so first of all we can write our joint +vector u1 + + align:start position:0% +vector u1 + + + align:start position:0% +vector u1 +equal to u dagger 1 + + align:start position:0% +equal to u dagger 1 + + + align:start position:0% +equal to u dagger 1 +gamma not and then just continue this + + align:start position:0% +gamma not and then just continue this + + + align:start position:0% +gamma not and then just continue this +rewriting + + align:start position:0% +rewriting + + + align:start position:0% +rewriting +until we find this part here the + + align:start position:0% +until we find this part here the + + + align:start position:0% +until we find this part here the +solution which looks a little bit + + align:start position:0% +solution which looks a little bit + + + align:start position:0% +solution which looks a little bit +simpler + + align:start position:0% +simpler + + + align:start position:0% +simpler +where we have um now their joint matrix + + align:start position:0% +where we have um now their joint matrix + + + align:start position:0% +where we have um now their joint matrix +instead of their joint + + align:start position:0% +instead of their joint + + + align:start position:0% +instead of their joint +joint matrix given here so we want to + + align:start position:0% +joint matrix given here so we want to + + + align:start position:0% +joint matrix given here so we want to +evaluate + + align:start position:0% +evaluate + + + align:start position:0% +evaluate +what this a joint q1 gamma + + align:start position:0% +what this a joint q1 gamma + + + align:start position:0% +what this a joint q1 gamma +u2 is times the joint u2 gamma + + align:start position:0% +u2 is times the joint u2 gamma + + + align:start position:0% +u2 is times the joint u2 gamma +the joint u1 okay good so this was just + + align:start position:0% +the joint u1 okay good so this was just + + + align:start position:0% +the joint u1 okay good so this was just +matrix + + align:start position:0% +matrix + + + align:start position:0% +matrix +algebra and working with camera matrix + + align:start position:0% +algebra and working with camera matrix + + + align:start position:0% +algebra and working with camera matrix +so far + + align:start position:0% +so far + + + align:start position:0% +so far +now we're using this completion relation + + align:start position:0% +now we're using this completion relation + + + align:start position:0% +now we're using this completion relation +um where i probably haven't told you yet + + align:start position:0% +um where i probably haven't told you yet + + + align:start position:0% +um where i probably haven't told you yet +what this + + align:start position:0% +what this + + + align:start position:0% +what this +um what this syntax here is + + align:start position:0% +um what this syntax here is + + + align:start position:0% +um what this syntax here is +so gamma flash is equal to gamma mu + + align:start position:0% +so gamma flash is equal to gamma mu + + + align:start position:0% +so gamma flash is equal to gamma mu +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +and that's just the way to simplify + + align:start position:0% +and that's just the way to simplify + + + align:start position:0% +and that's just the way to simplify +writing multiply the equation so if + + align:start position:0% +writing multiply the equation so if + + + align:start position:0% +writing multiply the equation so if +if you use this so-called find slash + + align:start position:0% +if you use this so-called find slash + + + align:start position:0% +if you use this so-called find slash +you can also rewrite the dirac equation + + align:start position:0% +you can also rewrite the dirac equation + + + align:start position:0% +you can also rewrite the dirac equation +in a simple form + + align:start position:0% +in a simple form + + + align:start position:0% +in a simple form +i del slash minus m + + align:start position:0% +i del slash minus m + + + align:start position:0% +i del slash minus m +y equal to zero that's now our directive + + align:start position:0% +y equal to zero that's now our directive + + + align:start position:0% +y equal to zero that's now our directive +remember there was a + + align:start position:0% +remember there was a + + + align:start position:0% +remember there was a +um gamma mu uh + + align:start position:0% +um gamma mu uh + + + align:start position:0% +um gamma mu uh +dnu here all right um that's just the + + align:start position:0% +dnu here all right um that's just the + + + align:start position:0% +dnu here all right um that's just the +cycle mark and we have to + + align:start position:0% +cycle mark and we have to + + + align:start position:0% +cycle mark and we have to +sum over all spin states uh or the spin + + align:start position:0% +sum over all spin states uh or the spin + + + align:start position:0% +sum over all spin states uh or the spin +states of all + + align:start position:0% +states of all + + + align:start position:0% +states of all +of all both particles now if we start + + align:start position:0% +of all both particles now if we start + + + align:start position:0% +of all both particles now if we start +with summing over particle two + + align:start position:0% +with summing over particle two + + + align:start position:0% +with summing over particle two +we can rewrite this here we use this + + align:start position:0% +we can rewrite this here we use this + + + align:start position:0% +we can rewrite this here we use this +equation this + + align:start position:0% +equation this + + + align:start position:0% +equation this +completely relation and just redefine + + align:start position:0% +completely relation and just redefine + + + align:start position:0% +completely relation and just redefine +this q as equal to this part here + + align:start position:0% + + + + align:start position:0% + +okay so now we have this equation here + + align:start position:0% +okay so now we have this equation here + + + align:start position:0% +okay so now we have this equation here +which looks a little bit simpler because + + align:start position:0% +which looks a little bit simpler because + + + align:start position:0% +which looks a little bit simpler because +we just have + + align:start position:0% +we just have + + + align:start position:0% +we just have +our um incoming and outgoing spinos + + align:start position:0% +our um incoming and outgoing spinos + + + align:start position:0% +our um incoming and outgoing spinos +for particle one given here + + align:start position:0% +for particle one given here + + + align:start position:0% +for particle one given here +all right now we're looking at this part + + align:start position:0% +all right now we're looking at this part + + + align:start position:0% +all right now we're looking at this part +of the equation now + + align:start position:0% +of the equation now + + + align:start position:0% +of the equation now +and again we're just doing a little bit + + align:start position:0% +and again we're just doing a little bit + + + align:start position:0% +and again we're just doing a little bit +of matrix + + align:start position:0% +of matrix + + + align:start position:0% +of matrix +algebra here we find that this is equal + + align:start position:0% +algebra here we find that this is equal + + + align:start position:0% +algebra here we find that this is equal +to uh qu1 u1 + + align:start position:0% +to uh qu1 u1 + + + align:start position:0% +to uh qu1 u1 +ii which is just simply summing over the + + align:start position:0% +ii which is just simply summing over the + + + align:start position:0% +ii which is just simply summing over the +same indices + + align:start position:0% +same indices + + + align:start position:0% +same indices +which is the same as building the trace + + align:start position:0% +which is the same as building the trace + + + align:start position:0% +which is the same as building the trace +of this matrix + + align:start position:0% +of this matrix + + + align:start position:0% +of this matrix +all right so if you just put all of + + align:start position:0% +all right so if you just put all of + + + align:start position:0% +all right so if you just put all of +those together he finds that + + align:start position:0% +those together he finds that + + + align:start position:0% +those together he finds that +calculating the sum of matrix elements + + align:start position:0% +calculating the sum of matrix elements + + + align:start position:0% +calculating the sum of matrix elements +is similar to building the trace of a + + align:start position:0% +is similar to building the trace of a + + + align:start position:0% +is similar to building the trace of a +matrix and then + + align:start position:0% +matrix and then + + + align:start position:0% +matrix and then +our final results think even though this + + align:start position:0% +our final results think even though this + + + align:start position:0% +our final results think even though this +one + + align:start position:0% +one + + + align:start position:0% +one +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +all right so summarizing this part + + align:start position:0% +all right so summarizing this part + + + align:start position:0% +all right so summarizing this part +we have a matrix element and we saw that + + align:start position:0% +we have a matrix element and we saw that + + + align:start position:0% +we have a matrix element and we saw that +the matrix elements of this form is + + align:start position:0% +the matrix elements of this form is + + + align:start position:0% +the matrix elements of this form is +proportional to this form + + align:start position:0% +proportional to this form + + + align:start position:0% +proportional to this form +and then when we try to calculate the + + align:start position:0% +and then when we try to calculate the + + + align:start position:0% +and then when we try to calculate the +spin average matrix element squared + + align:start position:0% +spin average matrix element squared + + + align:start position:0% +spin average matrix element squared +that's equal to the traces of the + + align:start position:0% +that's equal to the traces of the + + + align:start position:0% +that's equal to the traces of the +particles involved using the completion + + align:start position:0% +particles involved using the completion + + + align:start position:0% +particles involved using the completion +function there's an additional part one + + align:start position:0% +function there's an additional part one + + + align:start position:0% +function there's an additional part one +additional factor one half here which + + align:start position:0% +additional factor one half here which + + + align:start position:0% +additional factor one half here which +comes from the averaging over the + + align:start position:0% +comes from the averaging over the + + + align:start position:0% +comes from the averaging over the +initial spins + + align:start position:0% +initial spins + + + align:start position:0% +initial spins +so assuming exactly one of u1 and q2 + + align:start position:0% +so assuming exactly one of u1 and q2 + + + align:start position:0% +so assuming exactly one of u1 and q2 +corresponds to the initial to the + + align:start position:0% +corresponds to the initial to the + + + align:start position:0% +corresponds to the initial to the +initial particles we find this factor + + align:start position:0% +initial particles we find this factor + + + align:start position:0% +initial particles we find this factor +one half if both initial particles + + align:start position:0% +one half if both initial particles + + + align:start position:0% +one half if both initial particles +are the same like in perineulation + + align:start position:0% +are the same like in perineulation + + + align:start position:0% +are the same like in perineulation +then factor is one quarter and if + + align:start position:0% +then factor is one quarter and if + + + align:start position:0% +then factor is one quarter and if +neither is + + align:start position:0% +neither is + + + align:start position:0% +neither is +in the initial state then the factor is + + align:start position:0% +in the initial state then the factor is + + + align:start position:0% +in the initial state then the factor is +one one + + align:start position:0% +one one + + + align:start position:0% +one one +which you would have for a pair + + align:start position:0% +which you would have for a pair + + + align:start position:0% +which you would have for a pair +production + + align:start position:0% +production + + + align:start position:0% +production +okay good so now we simplified the + + align:start position:0% +okay good so now we simplified the + + + align:start position:0% +okay good so now we simplified the +calculation of + + align:start position:0% +calculation of + + + align:start position:0% +calculation of +our matrix elements putting the specific + + align:start position:0% +our matrix elements putting the specific + + + align:start position:0% +our matrix elements putting the specific +spin states in there in the specific + + align:start position:0% +spin states in there in the specific + + + align:start position:0% +spin states in there in the specific +polarization + + align:start position:0% +polarization + + + align:start position:0% +polarization +um vectors towards the calculation of + + align:start position:0% +um vectors towards the calculation of + + + align:start position:0% +um vectors towards the calculation of +traces of matrices so now we can look in + + align:start position:0% +traces of matrices so now we can look in + + + align:start position:0% +traces of matrices so now we can look in +what does it mean so what is that + + align:start position:0% +what does it mean so what is that + + + align:start position:0% +what does it mean so what is that +this is this is what carbonyl's trick + + align:start position:0% +this is this is what carbonyl's trick + + + align:start position:0% +this is this is what carbonyl's trick +really is about + + align:start position:0% +really is about + + + align:start position:0% +really is about +so summing over all spins reduces to + + align:start position:0% +so summing over all spins reduces to + + + align:start position:0% +so summing over all spins reduces to +coming over mattresses if you have + + align:start position:0% +coming over mattresses if you have + + + align:start position:0% +coming over mattresses if you have +anti-particles + + align:start position:0% +anti-particles + + + align:start position:0% +anti-particles +the completeness relation reduces to + + align:start position:0% +the completeness relation reduces to + + + align:start position:0% +the completeness relation reduces to +p slash minus m um + + align:start position:0% +p slash minus m um + + + align:start position:0% +p slash minus m um +and then we can go ahead so all you need + + align:start position:0% +and then we can go ahead so all you need + + + align:start position:0% +and then we can go ahead so all you need +to know now is how to do these traces + + align:start position:0% +to know now is how to do these traces + + + align:start position:0% +to know now is how to do these traces +so first some general remarks and traces + + align:start position:0% +so first some general remarks and traces + + + align:start position:0% +so first some general remarks and traces +if you have two matrices a and b + + align:start position:0% +if you have two matrices a and b + + + align:start position:0% +if you have two matrices a and b +you want to calculate the trace of a + + align:start position:0% +you want to calculate the trace of a + + + align:start position:0% +you want to calculate the trace of a +plus b + + align:start position:0% +plus b + + + align:start position:0% +plus b +that's equal to the trace of a plus + + align:start position:0% +that's equal to the trace of a plus + + + align:start position:0% +that's equal to the trace of a plus +trade of b + + align:start position:0% +trade of b + + + align:start position:0% +trade of b +if you have a multiplicator here a + + align:start position:0% +if you have a multiplicator here a + + + align:start position:0% +if you have a multiplicator here a +vector alpha you can just take this out + + align:start position:0% +vector alpha you can just take this out + + + align:start position:0% +vector alpha you can just take this out +of the + + align:start position:0% +of the + + + align:start position:0% +of the +of the calculation of the trace + + align:start position:0% +of the calculation of the trace + + + align:start position:0% +of the calculation of the trace +um thus in those traces + + align:start position:0% +um thus in those traces + + + align:start position:0% +um thus in those traces +two matrices commit communicate the + + align:start position:0% +two matrices commit communicate the + + + align:start position:0% +two matrices commit communicate the +trace of a times b + + align:start position:0% +trace of a times b + + + align:start position:0% +trace of a times b +is equal to the trace of b times a and + + align:start position:0% +is equal to the trace of b times a and + + + align:start position:0% +is equal to the trace of b times a and +then you can use this in order to show + + align:start position:0% +then you can use this in order to show + + + align:start position:0% +then you can use this in order to show +more complicated relations like this + + align:start position:0% +more complicated relations like this + + + align:start position:0% +more complicated relations like this +okay + + align:start position:0% + + + + align:start position:0% + +good um we have already started playing + + align:start position:0% +good um we have already started playing + + + align:start position:0% +good um we have already started playing +around with the gamma matrices here are + + align:start position:0% +around with the gamma matrices here are + + + align:start position:0% +around with the gamma matrices here are +a few more identities which might be of + + align:start position:0% +a few more identities which might be of + + + align:start position:0% +a few more identities which might be of +use when you calculate + + align:start position:0% +use when you calculate + + + align:start position:0% +use when you calculate +traces and you calculate matrix elements + + align:start position:0% +traces and you calculate matrix elements + + + align:start position:0% +traces and you calculate matrix elements +overall the first one is this + + align:start position:0% +overall the first one is this + + + align:start position:0% +overall the first one is this +g minou times g minou is equal to four + + align:start position:0% +g minou times g minou is equal to four + + + align:start position:0% +g minou times g minou is equal to four +um the anti-community commutator + + align:start position:0% +um the anti-community commutator + + + align:start position:0% +um the anti-community commutator +relation we already discussed and have + + align:start position:0% +relation we already discussed and have + + + align:start position:0% +relation we already discussed and have +shown + + align:start position:0% +shown + + + align:start position:0% +shown +in our one of our presentation and if + + align:start position:0% +in our one of our presentation and if + + + align:start position:0% +in our one of our presentation and if +you have three matrices you can rewrite + + align:start position:0% +you have three matrices you can rewrite + + + align:start position:0% +you have three matrices you can rewrite +them + + align:start position:0% +them + + + align:start position:0% +them +as minus two times the metric + + align:start position:0% +as minus two times the metric + + + align:start position:0% +as minus two times the metric +which is in the middle here okay + + align:start position:0% +which is in the middle here okay + + + align:start position:0% +which is in the middle here okay +so i'm not going through this in much + + align:start position:0% +so i'm not going through this in much + + + align:start position:0% +so i'm not going through this in much +detail here but i encourage you + + align:start position:0% +detail here but i encourage you + + + align:start position:0% +detail here but i encourage you +to just follow those additional exercise + + align:start position:0% +to just follow those additional exercise + + + align:start position:0% +to just follow those additional exercise +if you didn't have the opportunity yet + + align:start position:0% +if you didn't have the opportunity yet + + + align:start position:0% +if you didn't have the opportunity yet +to play with those mattresses + + align:start position:0% +to play with those mattresses + + + align:start position:0% +to play with those mattresses +and then you can use those those tricks + + align:start position:0% +and then you can use those those tricks + + + align:start position:0% +and then you can use those those tricks +for example the anti-communic commutator + + align:start position:0% +for example the anti-communic commutator + + + align:start position:0% +for example the anti-communic commutator +relation + + align:start position:0% +relation + + + align:start position:0% +relation +to calculate the traces of + + align:start position:0% +to calculate the traces of + + + align:start position:0% +to calculate the traces of +uh for example gamma mu which is four + + align:start position:0% +uh for example gamma mu which is four + + + align:start position:0% +uh for example gamma mu which is four +times + + align:start position:0% +times + + + align:start position:0% +times +g minus okay so what you see here is i + + align:start position:0% +g minus okay so what you see here is i + + + align:start position:0% +g minus okay so what you see here is i +basically + + align:start position:0% +basically + + + align:start position:0% +basically +used this anti-community commutator + + align:start position:0% +used this anti-community commutator + + + align:start position:0% +used this anti-community commutator +relation + + align:start position:0% +relation + + + align:start position:0% +relation +put it in here use this part here + + align:start position:0% +put it in here use this part here + + + align:start position:0% +put it in here use this part here +this is basically one straight of one is + + align:start position:0% +this is basically one straight of one is + + + align:start position:0% +this is basically one straight of one is +four so + + align:start position:0% +four so + + + align:start position:0% +four so +we get gb mu times the trailer one + + align:start position:0% +we get gb mu times the trailer one + + + align:start position:0% +we get gb mu times the trailer one +over four times four matrix is four and + + align:start position:0% +over four times four matrix is four and + + + align:start position:0% +over four times four matrix is four and +so you get + + align:start position:0% +so you get + + + align:start position:0% +so you get +the trace of gamma mu common is + + align:start position:0% + + + + align:start position:0% + +okay and so on um later on um we haven't + + align:start position:0% +okay and so on um later on um we haven't + + + align:start position:0% +okay and so on um later on um we haven't +discussed gamma 5 yet so much + + align:start position:0% +discussed gamma 5 yet so much + + + align:start position:0% +discussed gamma 5 yet so much +gamma 5 is defined as i times gamma 0 + + align:start position:0% +gamma 5 is defined as i times gamma 0 + + + align:start position:0% +gamma 5 is defined as i times gamma 0 +comma 1 gamma 2 gamma 3. + + align:start position:0% +comma 1 gamma 2 gamma 3. + + + align:start position:0% +comma 1 gamma 2 gamma 3. +you will see when we discuss the weak + + align:start position:0% +you will see when we discuss the weak + + + align:start position:0% +you will see when we discuss the weak +interaction that there is a prominent + + align:start position:0% +interaction that there is a prominent + + + align:start position:0% +interaction that there is a prominent +role for gamma 5 this + + align:start position:0% +role for gamma 5 this + + + align:start position:0% +role for gamma 5 this +is very special common matrix and here + + align:start position:0% +is very special common matrix and here + + + align:start position:0% +is very special common matrix and here +are just some + + align:start position:0% +are just some + + + align:start position:0% +are just some +um pieces of information for traces for + + align:start position:0% +um pieces of information for traces for + + + align:start position:0% +um pieces of information for traces for +number five the trace of comma 5 is + + align:start position:0% +number five the trace of comma 5 is + + + align:start position:0% +number five the trace of comma 5 is +zero the j gamma five times + + align:start position:0% + + + + align:start position:0% + +a different gamma matrix is zero and + + align:start position:0% +a different gamma matrix is zero and + + + align:start position:0% +a different gamma matrix is zero and +that's also true for the products of + + align:start position:0% +that's also true for the products of + + + align:start position:0% +that's also true for the products of +additional gamma matrices which you can + + align:start position:0% +additional gamma matrices which you can + + + align:start position:0% +additional gamma matrices which you can +find when you + + align:start position:0% +find when you + + + align:start position:0% +find when you +just try to calculate this relation + + align:start position:0% + + + + align:start position:0% + +okay um one last piece of the + + align:start position:0% +okay um one last piece of the + + + align:start position:0% +okay um one last piece of the +uh traces with gamma matrices is shown + + align:start position:0% +uh traces with gamma matrices is shown + + + align:start position:0% +uh traces with gamma matrices is shown +here + + align:start position:0% +here + + + align:start position:0% +here +um only with four or more gamma matrices + + align:start position:0% +um only with four or more gamma matrices + + + align:start position:0% +um only with four or more gamma matrices +can you define + + align:start position:0% +can you define + + + align:start position:0% +can you define +or find a non-zero trace involving gamma + + align:start position:0% +or find a non-zero trace involving gamma + + + align:start position:0% +or find a non-zero trace involving gamma +matrices and here's one example + + align:start position:0% +matrices and here's one example + + + align:start position:0% +matrices and here's one example +where you have the product of five or + + align:start position:0% +where you have the product of five or + + + align:start position:0% +where you have the product of five or +four gamma matrices with gamma five + + align:start position:0% +four gamma matrices with gamma five + + + align:start position:0% +four gamma matrices with gamma five +and that's equal in this case 4 times i + + align:start position:0% +and that's equal in this case 4 times i + + + align:start position:0% +and that's equal in this case 4 times i +times + + align:start position:0% +times + + + align:start position:0% +times +the total asymmetric tensor the total + + align:start position:0% +the total asymmetric tensor the total + + + align:start position:0% +the total asymmetric tensor the total +asymmetry tender is defined as -1 + + align:start position:0% +asymmetry tender is defined as -1 + + + align:start position:0% +asymmetry tender is defined as -1 +for even permutations of those numbers + + align:start position:0% +for even permutations of those numbers + + + align:start position:0% +for even permutations of those numbers +here + + align:start position:0% +here + + + align:start position:0% +here +plus 1 for odd permutations and zero + + align:start position:0% +plus 1 for odd permutations and zero + + + align:start position:0% +plus 1 for odd permutations and zero +if there's two indexes all right + + align:start position:0% +if there's two indexes all right + + + align:start position:0% +if there's two indexes all right +again i'm not showing you this um + + align:start position:0% +again i'm not showing you this um + + + align:start position:0% +again i'm not showing you this um +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +in too much detail but i encourage you + + align:start position:0% +in too much detail but i encourage you + + + align:start position:0% +in too much detail but i encourage you +to you know play around and you will be + + align:start position:0% +to you know play around and you will be + + + align:start position:0% +to you know play around and you will be +asked in the homework in the next + + align:start position:0% +asked in the homework in the next + + + align:start position:0% +asked in the homework in the next +homework + + align:start position:0% +homework + + + align:start position:0% +homework +to play around with some of the + + align:start position:0% + + + + align:start position:0% + +calculations \ No newline at end of file diff --git a/sNLB6_ZIfX0.txt b/sNLB6_ZIfX0.txt new file mode 100644 index 0000000000000000000000000000000000000000..6ec82f2a60c10164b90912505d51c7278de522df --- /dev/null +++ b/sNLB6_ZIfX0.txt @@ -0,0 +1,387 @@ +PROFESSOR: Hi. + +Last time we talked about NVCC +method and how to reduce the + +number of equations we had +to deal with to solve a + +particular circuit. + +At this point, we're pretty +well equipped to solve + +circuits in the general sense, +but we really haven't talked + +about how to use that +information or possibly use + +circuits in a particular way. + +Before we jump into both that +and abstraction of circuits, + +we need to talk about op-amps. + +Op-amps is short for Operational +Amplifier. + +And it's a tool that we can +use in order to sample + +particular voltages from a +subsection of the circuit + +without affecting it. + +Another thing we can +use op-amps to do + +is modify our signal. + +Or if we're going to sample a +voltage from a particular + +subsection of the circuit, we +can then do stuff to that + +voltage without affecting the +circuit, all within the op-amp + +or within the op-amp's special +subset of circuitry. + +So first of all what is an +operational amplifier? + +Well, an operational amplifier +is a giant web of transistors. + +But what an operational +amplifier does is act as a + +voltage-dependent +voltage source. + +It can effectively sample +voltages from an existing + +circuit and then use them to +power some other object, for + +instance a light bulb. + +If you set up this kind of +circuit, you will not actually + +be powering this light bulb +with 5 Volts, because the + +light bulb itself acts +as a resistor. + +And so the voltage drop across +this part of the circuit is + +going to be different +from just 5 Volts. + +If you want to enable a voltage +drop of 5 Volts across + +this light bulb, then you have +to stick up an op-amp. + +You have to use an op-amp to +sample the voltage drop at + +this component and put it in +between the light bulb and the + +rest of the circuit. + +When you see an op-amp on a +schematic diagram, it'll + +frequently look like this. + +You'll have a positive input +voltage, a negative input + +voltage, power rails, which are +actually the thing that + +determine the range of +expressivity that the op-amp + +has, and an output voltage. + +In reality, the relationship +between the output voltage and + +then input voltages is something +like this, where K + +is a very large number. + +The effect that this has is +that Vout is going to be + +whatever Vout needs +to be, such that + +Vplus is equal to Vminus. + +That's the basic rule you want +to use when you're interacting + +with op-amps. + +So in this case, if we wanted to +power this light bulb with + +5 Volts, we would do something +like this. + +Excuse the sloppiness of +the second diagram. + +We still have our 10 Volt +voltage source. + +We still have our +voltage divider. + +This point samples 5 Volts +from this sub-circuit -- + +and isolates this part of the +circuit from the light bulb. + +Vout has to be whatever value +is necessary such that this + +sample point and this sample +point are equal. + +Since this value is 5 Volts, +this value will also be driven + +to 5 Volts by the op-amp, +which means that + +this value is 5 Volts. + +And we've successfully +managed to power a + +light bulb with 5 Volts. + +The other thing you might be +asked to do is to take an + +existing schematic, an existing +circuit diagram and + +figure out what the operational +amplifier does to + +a given signal or possibly what +Vout is or possibly what + +Vout is in terms of +the input signal. + +So let's practice using +this diagram. + +Here's what we're after. + +I'm going to figure out where +Vplus is going to be. + +This is another voltage +divider. + +I'm now interested in Vminus, +in terms of Vout, which is + +another voltage divider. + +I can set these two equations +equal to one another + +and solve for Vout. + +I found a new expression for +Vout in the particular case + +where V is 10 Volts. + +If my input voltage were +previously unspecified, or if + +this voltage source were not +specified or just Vin, then I + +would be after this +expression. + +Some things I'd like to mention, +while we're talking + +about op-amps, all the +operational amplifiers we've + +been working with so far deal +with Vout in terms of Vin, + +where Vin is driven through the +positive terminal, and the + +negative terminal is typically +connected to ground. + +You can do the opposite +and end up with + +some interesting effects. + +But it comes at a cost. + +It is entirely possible that you +will end up driving your + +op-amp to an unstable +equilibrium. + +What you need to look at +is this relationship. + +There may be a particular point, +in which case your + +system is stable. + +But if you get any sort of minor +perturbations, you'll + +actually end up with +divergence. + +If this is the case, then +you'll probably + +burn out your op-amp. + +You can do this by hooking +it up in this way. + +This is expensive and could +possibly burn you. + +The other thing to note is that +the power rails on your + +op-amp limit its range +of expressivity. + +And I think I've said this +before, but it's worth + +mentioning again. + +If your op-amp is only powered +by 10 Volts, it cannot amplify + +your input signal to a final +value greater than 10 Volts. + +Likewise, if your input value +is a negative voltage, and + +you're working with a +non-inverting amplifier, if + +your ground is truly ground or +if your ground is higher + +relative than your input +voltage, you cannot actually + +express a negative voltage. + +The third thing I'd like to +quickly mention is that there + +are some terms associated with +op-amps that you might hear + +used by the staff or online, +that sort of thing. + +A buffer and a voltage follower +are the same thing. + +And that's explicitly when you +want to sample a signal or you + +want to sample a particular +voltage, and you don't want to + +multiply it or add it to +something or do any kind of + +LTI operations that we might be +able to do using op-amps in + +this course. + +You can work with amplifiers. + +And the thing we worked with +earlier was an amplifier for a + +value less than 1. + +You can also use op-amps +to some signals. + +And if you look for a voltage +summer amplifier on the + +internet, you should be able +to find some information. + +In any case, op-amps are +really powerful. + +They allow us to both isolate +a particular section of a + +circuit and sample a particular +voltage value from + +that circuit without affecting +that circuit, and also allow + +us to modify that particular +voltage value before using it + +in another part of our +overall circuit. + +Therefore, we're enabled to +design more complicated and + +powerful things. + +Next time, I'll talk about +superposition and Thevenin + +Norton equivalence, which will +further enable modularity and + +abstraction in our +circuit design. \ No newline at end of file diff --git a/w4uxYDPsjbw.txt b/w4uxYDPsjbw.txt new file mode 100644 index 0000000000000000000000000000000000000000..7cba160c54cf075bbe82b115daf955d3cf827a77 --- /dev/null +++ b/w4uxYDPsjbw.txt @@ -0,0 +1,147 @@ +align:start position:0% + +The following content is provided under + + align:start position:0% +The following content is provided under + + + align:start position:0% +The following content is provided under +a Creative Common License. Your support + + align:start position:0% +a Creative Common License. Your support + + + align:start position:0% +a Creative Common License. Your support +will help MIT Open Courseware continue + + align:start position:0% +will help MIT Open Courseware continue + + + align:start position:0% +will help MIT Open Courseware continue +to offer high-quality educational + + align:start position:0% +to offer high-quality educational + + + align:start position:0% +to offer high-quality educational +resources for free. To make a donation + + align:start position:0% +resources for free. To make a donation + + + align:start position:0% +resources for free. To make a donation +or view additional materials from + + align:start position:0% +or view additional materials from + + + align:start position:0% +or view additional materials from +hundreds of MIT courses, visit MIT Open + + align:start position:0% +hundreds of MIT courses, visit MIT Open + + + align:start position:0% +hundreds of MIT courses, visit MIT Open +Courseware at ocw.mmit.edu. + + align:start position:0% + + + + align:start position:0% + +So I have this variable name once which + + align:start position:0% +So I have this variable name once which + + + align:start position:0% +So I have this variable name once which +is um um MBR. Looks like people are + + align:start position:0% +is um um MBR. Looks like people are + + + align:start position:0% +is um um MBR. Looks like people are +getting it. We have a variable called + + align:start position:0% +getting it. We have a variable called + + + align:start position:0% +getting it. We have a variable called +repeat which is E L A and I'm creating a + + align:start position:0% +repeat which is E L A and I'm creating a + + + align:start position:0% +repeat which is E L A and I'm creating a +variable U which is the concatenation of + + align:start position:0% +variable U which is the concatenation of + + + align:start position:0% +variable U which is the concatenation of +that with the repeat + + align:start position:0% +that with the repeat + + + align:start position:0% +that with the repeat +U multiplied by four. So I think people + + align:start position:0% +U multiplied by four. So I think people + + + align:start position:0% +U multiplied by four. So I think people +are on the right track. Seeing by the + + align:start position:0% +are on the right track. Seeing by the + + + align:start position:0% +are on the right track. Seeing by the +90% here it's going to give me u this + + align:start position:0% +90% here it's going to give me u this + + + align:start position:0% +90% here it's going to give me u this +result right here. + + align:start position:0% +result right here. + + + align:start position:0% +result right here. +Great. \ No newline at end of file diff --git a/y4EcXTVqFb4.txt b/y4EcXTVqFb4.txt new file mode 100644 index 0000000000000000000000000000000000000000..96fc4014ca3515a1dc5de1ce627416fbe29c36f2 --- /dev/null +++ b/y4EcXTVqFb4.txt @@ -0,0 +1,1228 @@ +NARRATOR: The following content +is provided under a + +Creative Commons license. + +Your support will help MIT +OpenCourseWare continue to + +offer high-quality educational +resources for free. + +To make a donation or to view +additional materials from + +hundreds of MIT courses, visit +MIT OpenCourseWare at + +ocw.mit.edu. + +PROFESSOR: Hi. + +Our lecture today actually has +us backtrack a little bit to a + +concept which is actually more +fundamental than that of + +differentiability. + +It's a topic which is called +'continuous functions'. + +In other words, our lecture +today is concerned with a + +topic called Continuity. + +And actually, the topic of +continuity had its roots way + +back at the beginning of our +course when we first raised + +the question: does the limit of +'f of x' as 'x' approaches + +'a' equal 'f of a'? + +Remember, when we first started +talking about the + +limit concept, our intuitive +approach was to say, look-it, + +as 'x' gets arbitrarily close +to 'a', 'f of x' gets + +arbitrarily close to 'f of a'. + +And we saw that this particular +definition had a + +few loopholes in it, even though +intuitively this is + +what we would have liked. + +And so what I want to do today +is to see what happens if we + +can be sure that the limit of 'f +of x' as 'x' approaches 'a' + +equals 'f of a'. + +What is implied if this happens + +to be a true statement? + +And my first claim is that it is +implicitly implied that 'f + +of a' must at least +make sense. + +Otherwise, we wouldn't have +written it over here. + +In other words, 'f' must be +defined when 'x' equals 'a'. + +'f of a' must be defined. + +Now to correlate that with +material that we've had + +previously, let's go back +to an example that we've + +discussed before, or at least +an example which is close to + +something we've studied +before. + +Let's define 'f of x' to be 'x +squared minus 1' over 'x - 1'. + +Now you see as long as 'x' is +not equal to 1, we can cancel + +'x - 1' from both numerator and +denominator, leaving this + +equal to 'x + 1'. + +And we then see what? + +That the limit of 'f of +x' as 'x' approaches + +1 is equal to 2. + +On the other hand, notice that +'f of 1' turns out to be 0/0 + +in this case, which +is undefined. + +In other words, in this +particular case, the limit of + +'f of x' as 'x' approaches 1 +is not equal to 'f of 1' if + +only because 'f of 1' +isn't even defined. + +And again, by way of a review, +let's look at this thing + +pictorially. + +Remember, 'x squared minus 1' +over 'x - 1' is 'x + 1' except + +when 'x' equals 1. + +Consequently, to graph 'y' +equals 'x squared minus 1' + +over 'x - 1', we simply graph +'y' equals 'x + 1' with the + +point corresponding to 'x' +equals 1, meaning the point 1 + +comma 2 deleted. + +In other words, this point +deleted is the graph 'y' + +equals 'x squared minus +1' over 'x - 1'. + +You see again there is no +definition at 'x' equals 1 + +because this point is missing. + +It would be the 0/0 form. + +Now, to be sure, we can clean +this up in the sense that we + +could define a new function 'g +of x' to be 'x squared minus + +1' over 'x - 1' as long as 'x' +is not equal to 1 and define + +it to be 2 when 'x' equals +1, which, by the way, + +geometrically is just a fancy +way of writing the equation of + +the line 'y' equals 'x + 1'. + +In other words, all we're saying +is that letting 'g of + +x' be 2 when 'x' equals 1 plugs +the little hole to the + +periods over here. + +Now again, I hope that this +seems fairly familiar from our + +discussion on limits, but for +the time being, all I want us + +to see is that as soon as you +write down that the limit of + +'f of x' as 'x' approaches 'a' +equals 'f of a', you at least + +imply that 'f of a' +must be defined. + +Let's see another property +that's implied by our + +definition. + +I claim, as you might expect, +that if the limit of 'f of x' + +as 'x' approaches 'a' is 'f of +a', that means that 'f of x' + +is near 'f of a' when +'x' is near 'a'. + +In other words, my claim is that +the curve 'y' equals 'f + +of x' is unbroken in +a neighborhood + +of 'x' equals 'a'. + +And to see what I mean by +that, let's look at this + +picture over here. + +Suppose, for example, that our +curve 'y' equals 'f of x'-- + +let me darken this up so that we +can see it a little better. + +Suppose that curve had a break +at 'x' equals 'a', OK? + +Now, let's say 'f of +a' is over here. + +What I could do is now pick an +interval surrounding 'f of a', + +if there was a break over here, +such that this band + +never touched or included +the top curve here. + +Now notice, from this point of +view, that no matter how close + +'x' gets to 'a', as long as 'x' +is greater than 'a', 'f of + +x', which is up here on this +dark curve, can never be + +within epsilon of 'f of a'. + +In other words, if there's a +break in the curve I could + +always fix it up so that the +limit of 'f of x' as 'x' + +approaches 'a' is not +equal to 'f of a'. + +At any rate, with these two +properties as motivation, let + +us now give our basic +definition. + +And the basic definition is +simply this: a function 'f' is + +called continuous that 'x' +equals 'a' precisely if the + +property that we were discussing +is present, namely, + +if the limit of 'f of x' as +'x' approaches 'a' is + +equal to 'f of a'. + +We generalize this definition +and say 'f' is called + +continuous on the entire +interval 'I', or on the + +interval 'I', if the limit of 'f +of x' as 'x' approaches 'a' + +is equal to 'f of a' for +each 'a' in 'I'. + +In other words, notice that +our first definition is a + +local property. + +Namely, we define continuous or + +continuity at a given value. + +And then if the function happens +to be continuous at + +every point, then we call the +function itself continuous. + +What the thing means pictorially +is that if the + +function is continuous at 'x' +equals 'a', it means that in + +terms of the graph of the +function, that in a + +neighborhood of the point 'a' +comma 'f' of a on the graph, + +in a neighborhood of that point, +in other words, in a + +sufficiently small interval +surrounding that point, the + +curve itself must be unbroken. + +Now, you see, this may +sound trivial. + +Remember, when we first started +talking about limits, + +we had the feeling that limit of +'f of x' as 'x' approaches + +a should always equal +'f of a'. + +And the reason for this was that +instinctively we seem to + +always think of continuous +functions. + +We think of what? + +Things changing in such a way +the graph of the change is + +unbroken even though, of course, +there are places where + +discontinuities occur. + +At any rate, what I'm saying +is that many of the results + +that I now want to discuss +with you, which are very + +important properties of +continuous functions, may seem + +self-evident because we keep +thinking about any function as + +being continuous. + +But I will try to emphasize the +fact that these properties + +are not true if the function +is not continuous. + +I also would like to show a +balance between geometric + +ideas and analytic ideas. + +In other words, let me start off +by seeing what things seem + +to follow about continuous +functions based primarily on + +the graph idea. + +For example, I claimed that +continuous functions assume + +their maximum and minimum values +on any closed interval. + +Now, this sounds like a big +mouthful, and it also sounds + +kind of trivial. + +You say doesn't any function +have a maximum and minimum + +value on a closed interval? + +And the answer is no. + +For example, take the +curve 'y' equals '1 + +over ''x - 1' squared''. + +Notice that when 'x' is 1, 'y' +is infinite, which means that + +if we graph this particular +function, we find that the + +graph does something +like this. + +In other words, it goes-- + +it jumps up here, comes +back, et cetera. + +Now, what is the highest value +or what is the highest point + +on our graph here? + +Well, notice that the graph +is broken here. + +It's discontinuous when +'x' equals 1. + +Notice that the curve +rises to infinity. + +In other words, the maximum +value is undefined on this + +particular closed interval. + +You see there's a +jump over here. + +Of course, the fact that this +is an infinite jump may make + +you feel uneasy if +you don't feel + +comfortable with infinity. + +So let me paraphrase this just +a little bit in terms of a + +finite jump. + +Let me write down the +following function. + +Let's think of the function 'f +of x' equals 'x' if 'x' is + +less than 1. + +Then as soon as 'x' is at +least as big as 1, the + +function becomes 'minus x'. + +In other words, graphically, +we have the line 'y' equals + +'x' from 0 up to 1, but +not including 1. + +And then at 1, the function +jumps down to minus 1 and + +becomes the line 'y' +equals 'minus x'. + +Let's look, for example, +at the closed interval + +again from 0 to 2. + +What is the biggest value? + +What is the maximum that the +function can have if 'x' is + +between 0 and 2? + +Well, notice that as 'x' gets +closer and closer to 1, 'f of + +x' gets closer and closer to 1, +But 'f of x' never equals + +exactly 1, because when +'x' is 1, the curve + +jumps down to here. + +In other words, notice that as +'x' gets arbitrarily close to + +1, 'f of x' increases and gets +arbitrarily close to but + +never equals 1. + +In other words, notice that by +picking 'x' to be less than 1, + +we can make 'f of x' as close +to 1 as we want, but we can + +never make it exactly equal to +1 because of this jump which + +takes place over here. + +You see, this discontinuity +causes us a little bit of + +difficulty. + +By the way, we can use +this example from + +another point of view. + +If we just look at the part +where it says 'f of x' is + +equal to 'x' where 'x' is less +than 1, that means that we'll + +just look at this part +of the curve. + +Notice that this part of +the curve is unbroken. + +And yet as 'x' approaches 1, 'f +of x' approaches but never + +equals 1, which means that to +get the maximum value in here, + +I would have to include the +end point 'x' equals 1. + +In other words, notice that +even if the function is + +continuous, if the interval is +open, it may not assume the + +maximum value. + +In other words, you may not be +able to find the value of 'x' + +in that interval such as the +function will be maximum at + +that particular value. + +Now again, this is making a +mountain out of a mole hill in + +terms of your intuition because +these are result which + +I'm sure you believe +are true anyway. + +In other words, it +seems to be true. + +But all I hope is that these +little examples here show you + +what the importance of +continuity is, because as we + +progress later in our work, +these so called fine points + +are going to become crucial +in many of our proofs. + +And by the way, I think it's a +truism to say that if you make + +fine points seem very, very +important before you get to + +use them and don't emphasize +them, people tend to think + +that you overestimated +your case. + +So I prefer not to beat this to +death and wait until such + +times in our course that we need +these results before I + +emphasize them more. + +So these are results which are +in the textbook, which I'll + +test you on in the exercises and +the like, but just want to + +go through with you now so that +you get an overall idea. + +Another result that's rather +clear geometrically is + +something called the +intermediate value theorem. + +Suppose that 'f' is continuous +on the closed interval from + +'a' to 'b'. + +And without loss of generality, +let's suppose 'f + +of a' is less than 'f of b'. + +The same kind of an argument +would hold if 'f of b' were + +less than 'f of a', but I just +need some sort of an + +orientation. + +Now I say let 'm' be any number +such that m is what? + +Between 'f of a' and 'f of b'. + +In other words, 'm' is greater +than 'f of a' but + +less than 'f of b'. + +You see, if 'f of b' were less +than 'f of a', I would just + +reverse the inequality +signs here. + +At any rate, what my claim is +that we can find the number + +'c' in the open interval from +'a' to 'b' such that 'f of c' + +equals 'm'. + +Again, this may sound +kind of complicated. + +All it says in terms of +a picture is this. + +If our curve goes from point 1 +to point 2 where the height of + +'p1' is 'f of a' and the height +of 'p2' is 'f of b', + +then it must assume every +intermediary height between 'f + +of a' and 'f of b' on that +particular interval. + +Again, you can think of +that in terms of an + +automobile, if you want. + +If an automobile goes from a +speed of 20 miles an hour to a + +speed of 30 miles per hour in +what we think of as being + +continuous motion, then at some +time in that interval, it + +must've had any particular +speed you want to mention + +between 20 and 30 miles. + +In other words, we don't +visualize a car going from 20 + +miles an hour to 30 miles an +hour, say, without at one time + +having passed the speed +of 27 miles per hour + +or some such thing. + +And geometrically, you see, +this proof is very simple, + +namely, draw the line +'y' equals 'm'. + +And now what you're saying is +you want to get from this + +point to this point. + +And the idea is that the only +way you can get from this + +point to this point without +crossing this line is if + +someplace along the way, you +jump over this line. + +In other words, geometrically, +all you're saying is lookit, + +if I have to join 'p1' and 'p2' +with an unbroken line, + +then I must cross the line +'y' equals 'm' someplace. + +By the way, notice I say that at +least one place, the curve + +could have done something +like this, for example. + +But the important +point is what? + +There's at least one number +'c' such that 'f + +of c' equals 'm'. + +Again, somebody might think in +terms of an end run and say + +couldn't we have done something +like this and not + +cross this line? + +That brings us back again +to our concept of + +single-valuedness. + +In other words, notice, if we +remove the restriction that 'f + +be a' single-valued function, +in other words, if 'f' can + +double back, notice that if we +think of the line 'y' equals + +'m' as being endless, the +point remains what? + +That you must someplace cross +this line in going + +from 'p1' to 'p2'. + +But if we remove the +single-valued restriction, + +then the point at which +you cross this line + +would not have to be-- + +see, in this case, 'c' would +not be in the open interval + +from 'a' to 'b' since 'f' +is not single- valued. + +And what I'm hoping this +discussion does for us is + +gives us a good geometric +feeling as to what is + +happening in terms of a +continuous function. + +By the same token, remember +our basic definition of + +continuity goes back to +our concept of limit. + +And our concept of limit has +been cemented down fairly + +firmly from an analytical point +of view, and that means + +that we can also see these +things theoretically as well + +as pictorially. + +And hopefully what we will do +is combine pictorial and + +analytic aspects to +the best possible + +advantage for solving problems. + +But to show you what I mean by +this, let's look at a few + +analytical properties of +continuous functions. + +For example, suppose 'f' and 'g' +are both continuous at 'x' + +equals 'a'. + +And suppose we define 'h' to +be the sum of 'f' and 'g'. + +In other words, 'h of x' is 'f +of x' plus 'g of x', OK? + +Let's compute the limit of 'h +of x' as 'x' approaches 'a'. + +By definition, the limit of 'h +of x' as 'x' approaches 'a' is + +the limit of the quantity 'f +of x' plus 'g of x' as 'x' + +approaches 'a'. + +Now, if we look at this +particular expression, notice + +that because of our theorems on +limits, we can do an awful + +lot with this without having +to make any recourse to our + +picture at all. + +For example, notice that we can +say right away that since + +the limit of a sum is the sum +of the limits, this is the + +limit of 'f of x' as 'x' +approaches 'a' plus the limit + +of 'g of x' as 'x' +approaches 'a'. + +Secondly, since 'f' and 'g' are +continuous at 'x' equals + +'a', by definition of continuous +that 'x' equals + +'a', this says that the limit of +'f of x' as 'x' approaches + +'a' is 'f of a'. + +The limit of 'g of x' as 'x' +approaches 'a' is 'g of a'. + +Therefore, this expression is +'f of a' plus 'g of a'. + +But by the definition of 'h', +this is just 'h of a'. + +And if we now look at +this, we see what? + +That the limit of 'h of x' +as 'x' approaches 'a' + +equals 'h of a'. + +Notice that this result came +about under the assumption + +that 'f' and 'g' were both +continuous that 'x' equals + +'a', and what have we +proven over here? + +This is precisely the statement +that 'h' is + +continuous at 'x' equals 'a'. + +In other words, what we've now +proven analytically is that a + +sum of two continuous +functions is + +a continuous function. + +By induction, we could prove +this for the sum + +of more than two. + +We can in a similar way by using +limit theorems prove + +things like the product of two +continuous functions is + +continuous, et cetera. + +We also were on the verge of a +topic like this when we talked + +about differentiability +sometime back. + +Namely, I claim that there is +an interesting connection + +between differentiable and +continuous, and that the + +connection is that any +differentiable function is + +continuous. + +And by the way, the proofs +utilizes that which we used in + +our first lecture on derivatives +in this block. + +Namely, we take the expression +'f' of-- + +we want to show that if 'f prime +of a' exists, that 'f' + +must be continuous at +'x' equals 'a'. + +That means we want to show that +the limit of 'f of x' as + +'x' approaches 'a' is 'f of +a', and that's the same as + +saying we want to show that this +difference approaches 0 + +and the limit. + +And the trick is we take 'f of +x' minus 'f of a' and write it + +as ''f of x' minus 'f of a' +divided by 'x - a'' times 'x - + +a', the idea being that we'll +now take the limit as 'x' + +approaches 'a'. + +The limit of a product is the +product of the limits. + +The limit of this as 'x' +approaches 'a' is just going + +to be 'f prime of a'. + +That's our definition +of derivative. + +And the limit of 'x - a' as 'x' +approaches 'a' is just 0. + +In other words, putting +these steps together, + +look what we get. + +The limit as 'x' approaches 'a', +'f of x' minus 'f of a', + +is the limit as 'x' approaches +'a' of this bracketed + +expression ''f of x' minus 'f of +a' over 'x - a'' times the + +limit of 'x - a' as 'x' +approaches 'a'. + +By definition, 'f' being +differentiable at 'a' means + +that this limit exists and is, +in fact, 'f prime of a'. + +But any finite number +times 0 is still 0. + +And therefore, it follows that +the limit of 'f of x' as 'x' + +approaches 'a' is 'f of a'. + +There's a legitimate analytic +proof that differentiability + +implies continuity. + +Now, it's not necessarily true +that continuity implies + +differentiability. + +And you see even though you +can prove these things + +analytically, if you don't +form some picture in your + +mind, you frequently will my +wind up memorizing results + +rather than having a +feeling for them. + +What I mean by having pictures +and proofs coexist is this. + +Instead of saying to yourself, +let's see, continuity is a + +weaker condition than +differentiability, it's a + +strong-- which one is it? + +You say look-it. + +We identified continuity +with unbroken. + +Remember, continuous +means unbroken. + +What did differentiable mean? + +Differentiable meant that the +curve had a tangent line, and + +that, in turn, meant that +the curve was smooth. + +In other words, we may think +of differentiable as the + +geometric analog of smoothness, +continuity as the + +geometric analog of +unbrokenness. + +And now I think it's very easy +to see pictorially that a + +smooth curve must be unbroken, +but an unbroken curve doesn't + +have to be smooth. + +And in fact, a very trivial +illustration of this is the + +graph 'y' equals the absolute +value of 'x'. + +You see, well, what +happens here? + +At the origin, notice that we +have a sharp corner, but that + +the curve itself is +unbroken there. + +You see, I can draw the curve +without taking the pencil off + +the paper, the chalk +off the board. + +That's what continuity +means from an + +intuitive point of view. + +Yet I have a sharp corner. + +It's not smooth here. + +That's why I write smooth +in quotation marks. + +Hopefully, the textbook, +together with our exercises, + +will make this much +clear to you. + +But notice again in terms of +the picture how an unbroken + +curve doesn't have to be smooth, +but a smooth curve has + +to be unbroken. + +Now, the point is we +could say much more + +about continuous functions. + +I think that all we have +to say, though, has + +already been said. + +It'll be reinforced +in the text. + +We'll have exercises on this. + +But the important thing for now +is to understand what we + +mean by continuous, how we will +use it in the future, and + +at any rate, we'll be talking +about that more later. + +And so until next +time, goodbye. + +NARRATOR: Funding for the +publication of this video was + +provided by the Gabriella and +Paul Rosenbaum Foundation. + +Help OCW continue to provide +free and open access to MIT + +courses by making a donation +at ocw.mit.edu/donate. \ No newline at end of file diff --git a/z79v39lMR3k.txt b/z79v39lMR3k.txt new file mode 100644 index 0000000000000000000000000000000000000000..17d6d8165f7226d9a181b70fbdafe8ba1dbcfe25 --- /dev/null +++ b/z79v39lMR3k.txt @@ -0,0 +1,1827 @@ +align:start position:0% + +I've put on the blackboard here the + + align:start position:0% +I've put on the blackboard here the + + + align:start position:0% +I've put on the blackboard here the +things we were doing last time we began + + align:start position:0% +things we were doing last time we began + + + align:start position:0% +things we were doing last time we began +our study of stationary states that are + + align:start position:0% +our study of stationary states that are + + + align:start position:0% +our study of stationary states that are +not normalizable these are scattering + + align:start position:0% +not normalizable these are scattering + + + align:start position:0% +not normalizable these are scattering +states momentum eigenstates were not + + align:start position:0% +states momentum eigenstates were not + + + align:start position:0% +states momentum eigenstates were not +normalizable but now we have more + + align:start position:0% +normalizable but now we have more + + + align:start position:0% +normalizable but now we have more +interesting states that represent the + + align:start position:0% +interesting states that represent the + + + align:start position:0% +interesting states that represent the +solutions of the Schrodinger equation + + align:start position:0% +solutions of the Schrodinger equation + + + align:start position:0% +solutions of the Schrodinger equation +that are stationary States with some + + align:start position:0% +that are stationary States with some + + + align:start position:0% +that are stationary States with some +energy e because they are not + + align:start position:0% +energy e because they are not + + + align:start position:0% +energy e because they are not +normalizable we cannot directly + + align:start position:0% +normalizable we cannot directly + + + align:start position:0% +normalizable we cannot directly +interpret any of these solutions as the + + align:start position:0% +interpret any of these solutions as the + + + align:start position:0% +interpret any of these solutions as the +behavior of a particle I cannot tell you + + align:start position:0% +behavior of a particle I cannot tell you + + + align:start position:0% +behavior of a particle I cannot tell you +story okay so this is a particle is + + align:start position:0% +story okay so this is a particle is + + + align:start position:0% +story okay so this is a particle is +coming colliding doing something these + + align:start position:0% +coming colliding doing something these + + + align:start position:0% +coming colliding doing something these +are not normalizable states so part of + + align:start position:0% +are not normalizable states so part of + + + align:start position:0% +are not normalizable states so part of +what we're going to be trying to do + + align:start position:0% +what we're going to be trying to do + + + align:start position:0% +what we're going to be trying to do +today is connect to the picture of wave + + align:start position:0% +today is connect to the picture of wave + + + align:start position:0% +today is connect to the picture of wave +packets and see how this is used to + + align:start position:0% +packets and see how this is used to + + + align:start position:0% +packets and see how this is used to +really calculate what would happen if + + align:start position:0% +really calculate what would happen if + + + align:start position:0% +really calculate what would happen if +you send in a particle into potential + + align:start position:0% +you send in a particle into potential + + + align:start position:0% +you send in a particle into potential +nevertheless we wrote a solution that + + align:start position:0% +nevertheless we wrote a solution that + + + align:start position:0% +nevertheless we wrote a solution that +has roughly that interpretation at least + + align:start position:0% +has roughly that interpretation at least + + + align:start position:0% +has roughly that interpretation at least +they're morally speaking we think of a + + align:start position:0% +they're morally speaking we think of a + + + align:start position:0% +they're morally speaking we think of a +wave that is coming from the left + + align:start position:0% +wave that is coming from the left + + + align:start position:0% +wave that is coming from the left +that's a e to the ikx T now in order to + + align:start position:0% +that's a e to the ikx T now in order to + + + align:start position:0% +that's a e to the ikx T now in order to +have a wave you would have to have time + + align:start position:0% +have a wave you would have to have time + + + align:start position:0% +have a wave you would have to have time +dependence and this is a stationary + + align:start position:0% +dependence and this is a stationary + + + align:start position:0% +dependence and this is a stationary +solution and there is some time + + align:start position:0% +solution and there is some time + + + align:start position:0% +solution and there is some time +dependence there is exponential of e to + + align:start position:0% +dependence there is exponential of e to + + + align:start position:0% +dependence there is exponential of e to +the minus i e t over H bar or e is the + + align:start position:0% +the minus i e t over H bar or e is the + + + align:start position:0% +the minus i e t over H bar or e is the +energy so this could be out of here to + + align:start position:0% +energy so this could be out of here to + + + align:start position:0% +energy so this could be out of here to +produce the full stationary state sy of + + align:start position:0% +produce the full stationary state sy of + + + align:start position:0% +produce the full stationary state sy of +X and T but we'll leave it understood + + align:start position:0% +X and T but we'll leave it understood + + + align:start position:0% +X and T but we'll leave it understood +it's a common phase factor for both the + + align:start position:0% +it's a common phase factor for both the + + + align:start position:0% +it's a common phase factor for both the +solutions at X less than 0 and X greater + + align:start position:0% +solutions at X less than 0 and X greater + + + align:start position:0% +solutions at X less than 0 and X greater +than 0 because the whole solution + + align:start position:0% +than 0 because the whole solution + + + align:start position:0% +than 0 because the whole solution +represents a single solution it's not + + align:start position:0% +represents a single solution it's not + + + align:start position:0% +represents a single solution it's not +like a solution on the left and a + + align:start position:0% +like a solution on the left and a + + + align:start position:0% +like a solution on the left and a +solution on the right is a single + + align:start position:0% +solution on the right is a single + + + align:start position:0% +solution on the right is a single +solution over all of X for up sy that + + align:start position:0% +solution over all of X for up sy that + + + align:start position:0% +solution over all of X for up sy that +has some definite energy so + + align:start position:0% +has some definite energy so + + + align:start position:0% +has some definite energy so +we looked at the conditions of + + align:start position:0% +we looked at the conditions of + + + align:start position:0% +we looked at the conditions of +continuity of the wave function and + + align:start position:0% +continuity of the wave function and + + + align:start position:0% +continuity of the wave function and +continuty of the derivative of the wave + + align:start position:0% +continuty of the derivative of the wave + + + align:start position:0% +continuty of the derivative of the wave +function at x equals zero those were two + + align:start position:0% +function at x equals zero those were two + + + align:start position:0% +function at x equals zero those were two +conditions and they gave you this + + align:start position:0% +conditions and they gave you this + + + align:start position:0% +conditions and they gave you this +expressions for the ratios of C over a + + align:start position:0% +expressions for the ratios of C over a + + + align:start position:0% +expressions for the ratios of C over a +and B over a we could even imagine since + + align:start position:0% +and B over a we could even imagine since + + + align:start position:0% +and B over a we could even imagine since +we can't normalize this setting a equal + + align:start position:0% +we can't normalize this setting a equal + + + align:start position:0% +we can't normalize this setting a equal +to 1 and then calculating B and C from + + align:start position:0% +to 1 and then calculating B and C from + + + align:start position:0% +to 1 and then calculating B and C from +those numbers we have to Kasich a in a K + + align:start position:0% +those numbers we have to Kasich a in a K + + + align:start position:0% +those numbers we have to Kasich a in a K +bar the K is relevant to the wave + + align:start position:0% +bar the K is relevant to the wave + + + align:start position:0% +bar the K is relevant to the wave +function for X less than 0 the k bar is + + align:start position:0% +function for X less than 0 the k bar is + + + align:start position:0% +function for X less than 0 the k bar is +relevant for X greater than 0 they have + + align:start position:0% +relevant for X greater than 0 they have + + + align:start position:0% +relevant for X greater than 0 they have +to be different because this represents + + align:start position:0% +to be different because this represents + + + align:start position:0% +to be different because this represents +a de Broglie wavelength and the de + + align:start position:0% +a de Broglie wavelength and the de + + + align:start position:0% +a de Broglie wavelength and the de +Broglie wavelength encodes the momentum + + align:start position:0% +Broglie wavelength encodes the momentum + + + align:start position:0% +Broglie wavelength encodes the momentum +of the particle and the momentum of the + + align:start position:0% +of the particle and the momentum of the + + + align:start position:0% +of the particle and the momentum of the +particle that we imagined here + + align:start position:0% +particle that we imagined here + + + align:start position:0% +particle that we imagined here +classically is different here where this + + align:start position:0% +classically is different here where this + + + align:start position:0% +classically is different here where this +has this much kinetic energy and in the + + align:start position:0% +has this much kinetic energy and in the + + + align:start position:0% +has this much kinetic energy and in the +region on the right where the particle + + align:start position:0% +region on the right where the particle + + + align:start position:0% +region on the right where the particle +only has a much smaller kinetic energy + + align:start position:0% +only has a much smaller kinetic energy + + + align:start position:0% +only has a much smaller kinetic energy +so that's represented by K bar and K bar + + align:start position:0% +so that's represented by K bar and K bar + + + align:start position:0% +so that's represented by K bar and K bar +being the energy proportional to the + + align:start position:0% +being the energy proportional to the + + + align:start position:0% +being the energy proportional to the +energy minus V naught well K squared has + + align:start position:0% +energy minus V naught well K squared has + + + align:start position:0% +energy minus V naught well K squared has +just the energy is smaller than K so + + align:start position:0% +just the energy is smaller than K so + + + align:start position:0% +just the energy is smaller than K so +this is what with it we essentially + + align:start position:0% +this is what with it we essentially + + + align:start position:0% +this is what with it we essentially +solve the problem and this qualifies as + + align:start position:0% +solve the problem and this qualifies as + + + align:start position:0% +solve the problem and this qualifies as +a solution but we still haven't learned + + align:start position:0% +a solution but we still haven't learned + + + align:start position:0% +a solution but we still haven't learned +anything very interesting from it we + + align:start position:0% +anything very interesting from it we + + + align:start position:0% +anything very interesting from it we +have to understand more what's going on + + align:start position:0% +have to understand more what's going on + + + align:start position:0% +have to understand more what's going on +and one thing we can do is a think of a + + align:start position:0% +and one thing we can do is a think of a + + + align:start position:0% +and one thing we can do is a think of a +particular limit the limit or the case + + align:start position:0% +particular limit the limit or the case + + + align:start position:0% +particular limit the limit or the case +when e is equal to V not exactly equal + + align:start position:0% +when e is equal to V not exactly equal + + + align:start position:0% +when e is equal to V not exactly equal +to V naught what happens well K bar + + align:start position:0% +to V naught what happens well K bar + + + align:start position:0% +to V naught what happens well K bar +would be equal to zero + + align:start position:0% + + + + align:start position:0% + +and if K bar is equal to zero you're + + align:start position:0% +and if K bar is equal to zero you're + + + align:start position:0% +and if K bar is equal to zero you're +going to have just the constant scene + + align:start position:0% +going to have just the constant scene + + + align:start position:0% +going to have just the constant scene +here but now if K bar is equal to zero + + align:start position:0% +here but now if K bar is equal to zero + + + align:start position:0% +here but now if K bar is equal to zero +first B is equal to a because then it's + + align:start position:0% +first B is equal to a because then it's + + + align:start position:0% +first B is equal to a because then it's +K over K so B is equal to a and C is + + align:start position:0% +K over K so B is equal to a and C is + + + align:start position:0% +K over K so B is equal to a and C is +equal to 2a and the solution would + + align:start position:0% +equal to 2a and the solution would + + + align:start position:0% +equal to 2a and the solution would +become Phi of x equals well a is equal + + align:start position:0% +become Phi of x equals well a is equal + + + align:start position:0% +become Phi of x equals well a is equal +to B so this is twice a times the cosine + + align:start position:0% +to B so this is twice a times the cosine + + + align:start position:0% +to B so this is twice a times the cosine +of K X when a is equal to B is a common + + align:start position:0% +of K X when a is equal to B is a common + + + align:start position:0% +of K X when a is equal to B is a common +factor call it a and this thing is the + + align:start position:0% +factor call it a and this thing is the + + + align:start position:0% +factor call it a and this thing is the +sum of two Exponential's with opposite + + align:start position:0% +sum of two Exponential's with opposite + + + align:start position:0% +sum of two Exponential's with opposite +signs that gives you the cosine and for + + align:start position:0% +signs that gives you the cosine and for + + + align:start position:0% +signs that gives you the cosine and for +C you have to a and since K bar is equal + + align:start position:0% +C you have to a and since K bar is equal + + + align:start position:0% +C you have to a and since K bar is equal +to zero well it's just a it's a number + + align:start position:0% +to zero well it's just a it's a number + + + align:start position:0% +to zero well it's just a it's a number +this is a normalizable but even the + + align:start position:0% +this is a normalizable but even the + + + align:start position:0% +this is a normalizable but even the +original solution isn't normalizable so + + align:start position:0% +original solution isn't normalizable so + + + align:start position:0% +original solution isn't normalizable so +we wouldn't worry too much about it so + + align:start position:0% +we wouldn't worry too much about it so + + + align:start position:0% +we wouldn't worry too much about it so +how does that look for x over here you + + align:start position:0% +how does that look for x over here you + + + align:start position:0% +how does that look for x over here you +have a cosine of KX so it's going to be + + align:start position:0% +have a cosine of KX so it's going to be + + + align:start position:0% +have a cosine of KX so it's going to be +doing this to the left that for X less + + align:start position:0% +doing this to the left that for X less + + + align:start position:0% +doing this to the left that for X less +than 0 and at this point in those like + + align:start position:0% +than 0 and at this point in those like + + + align:start position:0% +than 0 and at this point in those like +that + + align:start position:0% +that + + + align:start position:0% +that +just flat sigh of X and here is 2 a so + + align:start position:0% +just flat sigh of X and here is 2 a so + + + align:start position:0% +just flat sigh of X and here is 2 a so +there's nothing wrong with a solution in + + align:start position:0% +there's nothing wrong with a solution in + + + align:start position:0% +there's nothing wrong with a solution in +this case it's kind of a little strange + + align:start position:0% +this case it's kind of a little strange + + + align:start position:0% +this case it's kind of a little strange +that it becomes a constant but but + + align:start position:0% +that it becomes a constant but but + + + align:start position:0% +that it becomes a constant but but +perfectly okay + + align:start position:0% + + + + align:start position:0% + +what really helps you here is to find + + align:start position:0% +what really helps you here is to find + + + align:start position:0% +what really helps you here is to find +some conditions that Express the + + align:start position:0% +some conditions that Express the + + + align:start position:0% +some conditions that Express the +conservation of probability you see you + + align:start position:0% +conservation of probability you see you + + + align:start position:0% +conservation of probability you see you +have a stationary state solution now + + align:start position:0% +have a stationary state solution now + + + align:start position:0% +have a stationary state solution now +stationary states are our finest state + + align:start position:0% +stationary states are our finest state + + + align:start position:0% +stationary states are our finest state +they're not static States completely + + align:start position:0% +they're not static States completely + + + align:start position:0% +they're not static States completely +static state now for example if you have + + align:start position:0% +static state now for example if you have + + + align:start position:0% +static state now for example if you have +a loop and you have a current that never + + align:start position:0% +a loop and you have a current that never + + + align:start position:0% +a loop and you have a current that never +changes in time this is a stationary + + align:start position:0% +changes in time this is a stationary + + + align:start position:0% +changes in time this is a stationary +condition even in electromagnetism so + + align:start position:0% +condition even in electromagnetism so + + + align:start position:0% +condition even in electromagnetism so +what we imagine here is that we're going + + align:start position:0% +what we imagine here is that we're going + + + align:start position:0% +what we imagine here is that we're going +to have some current probability current + + align:start position:0% +to have some current probability current + + + align:start position:0% +to have some current probability current +that is coming from the left and some of + + align:start position:0% +that is coming from the left and some of + + + align:start position:0% +that is coming from the left and some of +it maybe bounces back and some of it + + align:start position:0% +it maybe bounces back and some of it + + + align:start position:0% +it maybe bounces back and some of it +goes forward but essentially if you + + align:start position:0% +goes forward but essentially if you + + + align:start position:0% +goes forward but essentially if you +think of the barrier whatever you look a + + align:start position:0% +think of the barrier whatever you look a + + + align:start position:0% +think of the barrier whatever you look a +little to the left of the barrier and a + + align:start position:0% +little to the left of the barrier and a + + + align:start position:0% +little to the left of the barrier and a +little to the right of the barrier + + align:start position:0% +little to the right of the barrier + + + align:start position:0% +little to the right of the barrier +whatever is coming in say must be going + + align:start position:0% +whatever is coming in say must be going + + + align:start position:0% +whatever is coming in say must be going +out there because probability cannot + + align:start position:0% +out there because probability cannot + + + align:start position:0% +out there because probability cannot +increase in this region it would be like + + align:start position:0% +increase in this region it would be like + + + align:start position:0% +increase in this region it would be like +saying that the particle son requires + + align:start position:0% +saying that the particle son requires + + + align:start position:0% +saying that the particle son requires +larger and larger probability to be in + + align:start position:0% +larger and larger probability to be in + + + align:start position:0% +larger and larger probability to be in +this this portion of the graph and that + + align:start position:0% +this this portion of the graph and that + + + align:start position:0% +this this portion of the graph and that +can't happen so probability current + + align:start position:0% +can't happen so probability current + + + align:start position:0% +can't happen so probability current +gives you a way to quantify some of the + + align:start position:0% +gives you a way to quantify some of the + + + align:start position:0% +gives you a way to quantify some of the +things that are happening here so + + align:start position:0% +things that are happening here so + + + align:start position:0% +things that are happening here so +probability current was J of X which was + + align:start position:0% +probability current was J of X which was + + + align:start position:0% +probability current was J of X which was +H bar over m imaginary part of size star + + align:start position:0% +H bar over m imaginary part of size star + + + align:start position:0% +H bar over m imaginary part of size star +D psi DX + + align:start position:0% + + + + align:start position:0% + +so let's compute the probability current + + align:start position:0% +so let's compute the probability current + + + align:start position:0% +so let's compute the probability current +let's compute for X less than 0 what is + + align:start position:0% +let's compute for X less than 0 what is + + + align:start position:0% +let's compute for X less than 0 what is +the probability current J of X we can + + align:start position:0% +the probability current J of X we can + + + align:start position:0% +the probability current J of X we can +call it the parabola curl on the left + + align:start position:0% +call it the parabola curl on the left + + + align:start position:0% +call it the parabola curl on the left +side I would have to substitute the + + align:start position:0% +side I would have to substitute the + + + align:start position:0% +side I would have to substitute the +value of the wave function for a for X + + align:start position:0% +value of the wave function for a for X + + + align:start position:0% +value of the wave function for a for X +less than 0 which is the top line there + + align:start position:0% +less than 0 which is the top line there + + + align:start position:0% +less than 0 which is the top line there +into this formula and see what is the + + align:start position:0% +into this formula and see what is the + + + align:start position:0% +into this formula and see what is the +current in fact I believe you've done + + align:start position:0% +current in fact I believe you've done + + + align:start position:0% +current in fact I believe you've done +that in an exercise some time ago and as + + align:start position:0% +that in an exercise some time ago and as + + + align:start position:0% +that in an exercise some time ago and as +you can imagine the current is + + align:start position:0% +you can imagine the current is + + + align:start position:0% +you can imagine the current is +proportional to the modulus of a squared + + align:start position:0% +proportional to the modulus of a squared + + + align:start position:0% +proportional to the modulus of a squared +the length of a squared the length of B + + align:start position:0% +the length of a squared the length of B + + + align:start position:0% +the length of a squared the length of B +squared also enters and the funny thing + + align:start position:0% +squared also enters and the funny thing + + + align:start position:0% +squared also enters and the funny thing +is between those two waves one that is + + align:start position:0% +is between those two waves one that is + + + align:start position:0% +is between those two waves one that is +going to the right and one that is going + + align:start position:0% +going to the right and one that is going + + + align:start position:0% +going to the right and one that is going +to the left that that's very visible in + + align:start position:0% +to the left that that's very visible in + + + align:start position:0% +to the left that that's very visible in +the current this is h-bar K over m a + + align:start position:0% +the current this is h-bar K over m a + + + align:start position:0% +the current this is h-bar K over m a +squared minus B squared it's a short + + align:start position:0% +squared minus B squared it's a short + + + align:start position:0% +squared minus B squared it's a short +computation might be okay when a good + + align:start position:0% +computation might be okay when a good + + + align:start position:0% +computation might be okay when a good +idea to do it again was done in the + + align:start position:0% +idea to do it again was done in the + + + align:start position:0% +idea to do it again was done in the +homework and X greater than 0 J right of + + align:start position:0% +homework and X greater than 0 J right of + + + align:start position:0% +homework and X greater than 0 J right of +X would be equal to H Bar K bar now that + + align:start position:0% +X would be equal to H Bar K bar now that + + + align:start position:0% +X would be equal to H Bar K bar now that +you know you can almost do it in your + + align:start position:0% +you know you can almost do it in your + + + align:start position:0% +you know you can almost do it in your +head the SI e to the I K bar X look + + align:start position:0% +head the SI e to the I K bar X look + + + align:start position:0% +head the SI e to the I K bar X look +what's happening from pi star you get + + align:start position:0% +what's happening from pi star you get + + + align:start position:0% +what's happening from pi star you get +the C star from sorry you get the C so + + align:start position:0% +the C star from sorry you get the C so + + + align:start position:0% +the C star from sorry you get the C so +that's going to be a C squared the face + + align:start position:0% +that's going to be a C squared the face + + + align:start position:0% +that's going to be a C squared the face +is going to cancel between the one here + + align:start position:0% +is going to cancel between the one here + + + align:start position:0% +is going to cancel between the one here +and the one on sy but the derivative + + align:start position:0% +and the one on sy but the derivative + + + align:start position:0% +and the one on sy but the derivative +will bring down an I K bar and the + + align:start position:0% +will bring down an I K bar and the + + + align:start position:0% +will bring down an I K bar and the +imaginary part of that is just K bar so + + align:start position:0% +imaginary part of that is just K bar so + + + align:start position:0% +imaginary part of that is just K bar so +the answer is this + + align:start position:0% + + + + align:start position:0% + +and these are the two currents now if we + + align:start position:0% +and these are the two currents now if we + + + align:start position:0% +and these are the two currents now if we +are doing things correctly the two + + align:start position:0% +are doing things correctly the two + + + align:start position:0% +are doing things correctly the two +currents should be the same whatever + + align:start position:0% +currents should be the same whatever + + + align:start position:0% +currents should be the same whatever +current exists to the left say a + + align:start position:0% +current exists to the left say a + + + align:start position:0% +current exists to the left say a +positive current that is coming in to + + align:start position:0% +positive current that is coming in to + + + align:start position:0% +positive current that is coming in to +the right must be the same another + + align:start position:0% +the right must be the same another + + + align:start position:0% +the right must be the same another +pleasant thing is that this current + + align:start position:0% +pleasant thing is that this current + + + align:start position:0% +pleasant thing is that this current +doesn't depend on the value of X as X is + + align:start position:0% +doesn't depend on the value of X as X is + + + align:start position:0% +doesn't depend on the value of X as X is +less than zero nor on the value of X + + align:start position:0% +less than zero nor on the value of X + + + align:start position:0% +less than zero nor on the value of X +when X is greater than zero and that's + + align:start position:0% +when X is greater than zero and that's + + + align:start position:0% +when X is greater than zero and that's +good for conservation it would be pretty + + align:start position:0% +good for conservation it would be pretty + + + align:start position:0% +good for conservation it would be pretty +bad as well if you look at two places + + align:start position:0% +bad as well if you look at two places + + + align:start position:0% +bad as well if you look at two places +for X less than zero and you find that + + align:start position:0% +for X less than zero and you find that + + + align:start position:0% +for X less than zero and you find that +the current is not the same so where is + + align:start position:0% +the current is not the same so where is + + + align:start position:0% +the current is not the same so where is +it accumulating what what's going on + + align:start position:0% +it accumulating what what's going on + + + align:start position:0% +it accumulating what what's going on +so the independence of these things from + + align:start position:0% +so the independence of these things from + + + align:start position:0% +so the independence of these things from +X this is constant and a constant is + + align:start position:0% +X this is constant and a constant is + + + align:start position:0% +X this is constant and a constant is +very important because this causes + + align:start position:0% +very important because this causes + + + align:start position:0% +very important because this causes +should be the same now whether or not + + align:start position:0% +should be the same now whether or not + + + align:start position:0% +should be the same now whether or not +you know about current conservation it's + + align:start position:0% +you know about current conservation it's + + + align:start position:0% +you know about current conservation it's +encoded in Schrodinger's equation and we + + align:start position:0% +encoded in Schrodinger's equation and we + + + align:start position:0% +encoded in Schrodinger's equation and we +solve showing our equation that's how we + + align:start position:0% +solve showing our equation that's how we + + + align:start position:0% +solve showing our equation that's how we +got this relations between B a and C so + + align:start position:0% +got this relations between B a and C so + + + align:start position:0% +got this relations between B a and C so +it better be that these two things are + + align:start position:0% +it better be that these two things are + + + align:start position:0% +it better be that these two things are +the same so J l squared J L for example + + align:start position:0% +the same so J l squared J L for example + + + align:start position:0% +the same so J l squared J L for example +I want put of X because it's just clear + + align:start position:0% +I want put of X because it's just clear + + + align:start position:0% +I want put of X because it's just clear +it doesn't depend on X 1 minus B over a + + align:start position:0% +it doesn't depend on X 1 minus B over a + + + align:start position:0% +it doesn't depend on X 1 minus B over a +squared a squared I'm starting to + + align:start position:0% +squared a squared I'm starting to + + + align:start position:0% +squared a squared I'm starting to +manipulate the left one and see if + + align:start position:0% +manipulate the left one and see if + + + align:start position:0% +manipulate the left one and see if +indeed the currents are the same and now + + align:start position:0% +indeed the currents are the same and now + + + align:start position:0% +indeed the currents are the same and now +I get h-bar K over m 1 minus B over a + + align:start position:0% +I get h-bar K over m 1 minus B over a + + + align:start position:0% +I get h-bar K over m 1 minus B over a +squared you know I put the modulus + + align:start position:0% +squared you know I put the modulus + + + align:start position:0% +squared you know I put the modulus +square but so far everything is real in + + align:start position:0% +square but so far everything is real in + + + align:start position:0% +square but so far everything is real in +this KK bar b AC all real that right no + + align:start position:0% +this KK bar b AC all real that right no + + + align:start position:0% +this KK bar b AC all real that right no +now complex numbers + + align:start position:0% +now complex numbers + + + align:start position:0% +now complex numbers +I'll have to be that careful B over a + + align:start position:0% +I'll have to be that careful B over a + + + align:start position:0% +I'll have to be that careful B over a +squared is K minus K bar over k plus K + + align:start position:0% +squared is K minus K bar over k plus K + + + align:start position:0% +squared is K minus K bar over k plus K +bar squared a squared and I fit that + + align:start position:0% +bar squared a squared and I fit that + + + align:start position:0% +bar squared a squared and I fit that +here maybe h-bar K over m now what up + + align:start position:0% +here maybe h-bar K over m now what up + + + align:start position:0% +here maybe h-bar K over m now what up +this is square so the sum squared passes + + align:start position:0% +this is square so the sum squared passes + + + align:start position:0% +this is square so the sum squared passes +here to the numerator minus the + + align:start position:0% +here to the numerator minus the + + + align:start position:0% +here to the numerator minus the +difference squared that's going to be a + + align:start position:0% +difference squared that's going to be a + + + align:start position:0% +difference squared that's going to be a +4k k bar over k plus k bar squared a + + align:start position:0% +4k k bar over k plus k bar squared a + + + align:start position:0% +4k k bar over k plus k bar squared a +squared and yes this seems to be working + + align:start position:0% +squared and yes this seems to be working + + + align:start position:0% +squared and yes this seems to be working +quite well flip this case these two case + + align:start position:0% +quite well flip this case these two case + + + align:start position:0% +quite well flip this case these two case +flip them around so the answer for JL so + + align:start position:0% +flip them around so the answer for JL so + + + align:start position:0% +flip them around so the answer for JL so +far is H bar now k bar because they flip + + align:start position:0% +far is H bar now k bar because they flip + + + align:start position:0% +far is H bar now k bar because they flip +that M and now I would have for K + + align:start position:0% +that M and now I would have for K + + + align:start position:0% +that M and now I would have for K +squared over this thing which is 2 K + + align:start position:0% +squared over this thing which is 2 K + + + align:start position:0% +squared over this thing which is 2 K +over k plus K bar squared on a squared + + align:start position:0% +over k plus K bar squared on a squared + + + align:start position:0% +over k plus K bar squared on a squared +and this quantity if I remember right is + + align:start position:0% +and this quantity if I remember right is + + + align:start position:0% +and this quantity if I remember right is +just C squared as you can see from there + + align:start position:0% +just C squared as you can see from there + + + align:start position:0% +just C squared as you can see from there +so indeed this is J right and it worked + + align:start position:0% +so indeed this is J right and it worked + + + align:start position:0% +so indeed this is J right and it worked +out + + align:start position:0% +out + + + align:start position:0% +out +this is J right so J left is equal to J + + align:start position:0% +this is J right so J left is equal to J + + + align:start position:0% +this is J right so J left is equal to J +right by current conservation so that's + + align:start position:0% +right by current conservation so that's + + + align:start position:0% +right by current conservation so that's +nice that's another way of getting + + align:start position:0% +nice that's another way of getting + + + align:start position:0% +nice that's another way of getting +insight into these coefficients and the + + align:start position:0% +insight into these coefficients and the + + + align:start position:0% +insight into these coefficients and the +kind of thing that makes you feel + + align:start position:0% +kind of thing that makes you feel + + + align:start position:0% +kind of thing that makes you feel +there's no chance you got this wrong + + align:start position:0% +there's no chance you got this wrong + + + align:start position:0% +there's no chance you got this wrong +it it all works well \ No newline at end of file diff --git a/zU1x6UK64gs.txt b/zU1x6UK64gs.txt new file mode 100644 index 0000000000000000000000000000000000000000..8f2709ca2118c56b4b3d2024aabbb14706f0ca25 --- /dev/null +++ b/zU1x6UK64gs.txt @@ -0,0 +1,2467 @@ +align:start position:0% + +let us look at an application of the + + align:start position:0% +let us look at an application of the + + + align:start position:0% +let us look at an application of the +probabilistic method to extremal set + + align:start position:0% +probabilistic method to extremal set + + + align:start position:0% +probabilistic method to extremal set +theory the extremal set theory concerns + + align:start position:0% +theory the extremal set theory concerns + + + align:start position:0% +theory the extremal set theory concerns +the study of families of sets that have + + align:start position:0% +the study of families of sets that have + + + align:start position:0% +the study of families of sets that have +certain desirable properties and asking + + align:start position:0% +certain desirable properties and asking + + + align:start position:0% +certain desirable properties and asking +questions such as what is the largest + + align:start position:0% +questions such as what is the largest + + + align:start position:0% +questions such as what is the largest +set family that you can have with such + + align:start position:0% +set family that you can have with such + + + align:start position:0% +set family that you can have with such +with such properties and in this video + + align:start position:0% +with such properties and in this video + + + align:start position:0% +with such properties and in this video +we'll focus on the following property of + + align:start position:0% +we'll focus on the following property of + + + align:start position:0% +we'll focus on the following property of +being an intersecting family this means + + align:start position:0% +being an intersecting family this means + + + align:start position:0% +being an intersecting family this means +a collection of sets A1 through a l such + + align:start position:0% +a collection of sets A1 through a l such + + + align:start position:0% +a collection of sets A1 through a l such +that these sets pairwise intersect in a + + align:start position:0% +that these sets pairwise intersect in a + + + align:start position:0% +that these sets pairwise intersect in a +non-empty intersection okay so we want + + align:start position:0% +non-empty intersection okay so we want + + + align:start position:0% +non-empty intersection okay so we want +sets A1 through a l such that whenever + + align:start position:0% +sets A1 through a l such that whenever + + + align:start position:0% +sets A1 through a l such that whenever +you take any two of these sets and take + + align:start position:0% +you take any two of these sets and take + + + align:start position:0% +you take any two of these sets and take +their intersection it is never the empty + + align:start position:0% +their intersection it is never the empty + + + align:start position:0% +their intersection it is never the empty +set so here are two basic questions that + + align:start position:0% +set so here are two basic questions that + + + align:start position:0% +set so here are two basic questions that +one can ask the first one which will + + align:start position:0% +one can ask the first one which will + + + align:start position:0% +one can ask the first one which will +turn out to be an easy warmup is what is + + align:start position:0% +turn out to be an easy warmup is what is + + + align:start position:0% +turn out to be an easy warmup is what is +the largest intersecting family of + + align:start position:0% +the largest intersecting family of + + + align:start position:0% +the largest intersecting family of +subsets of 1 through n so here there are + + align:start position:0% +subsets of 1 through n so here there are + + + align:start position:0% +subsets of 1 through n so here there are +in total two to the N subsets of 1 + + align:start position:0% +in total two to the N subsets of 1 + + + align:start position:0% +in total two to the N subsets of 1 +through + + align:start position:0% +through + + + align:start position:0% +through +n but if I want to only keep a + + align:start position:0% +n but if I want to only keep a + + + align:start position:0% +n but if I want to only keep a +collection of sets that's an + + align:start position:0% +collection of sets that's an + + + align:start position:0% +collection of sets that's an +intersecting family what is the largest + + align:start position:0% +intersecting family what is the largest + + + align:start position:0% +intersecting family what is the largest +family I can get and the second question + + align:start position:0% +family I can get and the second question + + + align:start position:0% +family I can get and the second question +which will turn out to be far more + + align:start position:0% +which will turn out to be far more + + + align:start position:0% +which will turn out to be far more +interesting and will involve an + + align:start position:0% +interesting and will involve an + + + align:start position:0% +interesting and will involve an +application of the probabilist method is + + align:start position:0% +application of the probabilist method is + + + align:start position:0% +application of the probabilist method is +a question what is the largest + + align:start position:0% +a question what is the largest + + + align:start position:0% +a question what is the largest +intersecting family of K element subsets + + align:start position:0% +intersecting family of K element subsets + + + align:start position:0% +intersecting family of K element subsets +of 1 through n so here n and K are + + align:start position:0% +of 1 through n so here n and K are + + + align:start position:0% +of 1 through n so here n and K are +inputs to the question so they are given + + align:start position:0% +inputs to the question so they are given + + + align:start position:0% +inputs to the question so they are given +and we're asked to find what is the + + align:start position:0% +and we're asked to find what is the + + + align:start position:0% +and we're asked to find what is the +largest intersecting family of K element + + align:start position:0% +largest intersecting family of K element + + + align:start position:0% +largest intersecting family of K element +subsets of 1 through + + align:start position:0% +subsets of 1 through + + + align:start position:0% +subsets of 1 through +n all right so the first question as I + + align:start position:0% +n all right so the first question as I + + + align:start position:0% +n all right so the first question as I +mentioned earlier turns out to be a + + align:start position:0% +mentioned earlier turns out to be a + + + align:start position:0% +mentioned earlier turns out to be a +fairly easy one and we'll solve it as a + + align:start position:0% +fairly easy one and we'll solve it as a + + + align:start position:0% +fairly easy one and we'll solve it as a +warmup so as an example just to + + align:start position:0% +warmup so as an example just to + + + align:start position:0% +warmup so as an example just to +illustrate what we're talking about if + + align:start position:0% +illustrate what we're talking about if + + + align:start position:0% +illustrate what we're talking about if +we look at all + + align:start position:0% +we look at all + + + align:start position:0% +we look at all +sets + + align:start position:0% + + + + align:start position:0% + +containing the element + + align:start position:0% + + + + align:start position:0% + +one well this collection of sets is + + align:start position:0% +one well this collection of sets is + + + align:start position:0% +one well this collection of sets is +intersecting because they all have the + + align:start position:0% +intersecting because they all have the + + + align:start position:0% +intersecting because they all have the +element one so every pair intersects in + + align:start position:0% +element one so every pair intersects in + + + align:start position:0% +element one so every pair intersects in +some set that contains the element one + + align:start position:0% +some set that contains the element one + + + align:start position:0% +some set that contains the element one +in particular non + + align:start position:0% +in particular non + + + align:start position:0% +in particular non +empty this collection of sets has size 2 + + align:start position:0% +empty this collection of sets has size 2 + + + align:start position:0% +empty this collection of sets has size 2 +to the n minus one because once you fix + + align:start position:0% +to the n minus one because once you fix + + + align:start position:0% +to the n minus one because once you fix +the element one the other elements can + + align:start position:0% +the element one the other elements can + + + align:start position:0% +the element one the other elements can +be in or not in the sets and they're two + + align:start position:0% +be in or not in the sets and they're two + + + align:start position:0% +be in or not in the sets and they're two +to the N minus one such possibilities + + align:start position:0% +to the N minus one such possibilities + + + align:start position:0% +to the N minus one such possibilities +right so a binary choice for each the + + align:start position:0% +right so a binary choice for each the + + + align:start position:0% +right so a binary choice for each the +elements outside + + align:start position:0% +elements outside + + + align:start position:0% +elements outside +one okay now this is just an example but + + align:start position:0% +one okay now this is just an example but + + + align:start position:0% +one okay now this is just an example but +it turns out this is the best that we + + align:start position:0% +it turns out this is the best that we + + + align:start position:0% +it turns out this is the best that we +can do + + align:start position:0% +can do + + + align:start position:0% +can do +because okay so the claims that we + + align:start position:0% +because okay so the claims that we + + + align:start position:0% +because okay so the claims that we +cannot do better or we cannot get an + + align:start position:0% +cannot do better or we cannot get an + + + align:start position:0% +cannot do better or we cannot get an +even larger set + + align:start position:0% +even larger set + + + align:start position:0% +even larger set +and this is because for + + align:start position:0% + + + + align:start position:0% + +every subset a of 1 through + + align:start position:0% + + + + align:start position:0% + +n and + + align:start position:0% + + + + align:start position:0% + +most one of + + align:start position:0% +most one of + + + align:start position:0% +most one of +a and the complement of + + align:start position:0% +a and the complement of + + + align:start position:0% +a and the complement of +a so the elements 1 through n subtract a + + align:start position:0% +a so the elements 1 through n subtract a + + + align:start position:0% +a so the elements 1 through n subtract a +so the complement of a and most one of + + align:start position:0% +so the complement of a and most one of + + + align:start position:0% +so the complement of a and most one of +these can be + + align:start position:0% + + + + align:start position:0% + +in the intersecting + + align:start position:0% + + + + align:start position:0% + +family so what we're doing here is + + align:start position:0% +family so what we're doing here is + + + align:start position:0% +family so what we're doing here is +pairing up the sets with their + + align:start position:0% +pairing up the sets with their + + + align:start position:0% +pairing up the sets with their +complement and because it's an + + align:start position:0% +complement and because it's an + + + align:start position:0% +complement and because it's an +intersecting family you cannot + + align:start position:0% +intersecting family you cannot + + + align:start position:0% +intersecting family you cannot +simultaneously have a set and its + + align:start position:0% +simultaneously have a set and its + + + align:start position:0% +simultaneously have a set and its +complement in this intersecting family + + align:start position:0% +complement in this intersecting family + + + align:start position:0% +complement in this intersecting family +and so this + + align:start position:0% +and so this + + + align:start position:0% +and so this +eliminates so this means that you can + + align:start position:0% +eliminates so this means that you can + + + align:start position:0% +eliminates so this means that you can +have at most half of all the two to the + + align:start position:0% +have at most half of all the two to the + + + align:start position:0% +have at most half of all the two to the +N sets thereby showing that this 2 to + + align:start position:0% +N sets thereby showing that this 2 to + + + align:start position:0% +N sets thereby showing that this 2 to +the N minus one is indeed the best that + + align:start position:0% +the N minus one is indeed the best that + + + align:start position:0% +the N minus one is indeed the best that +you can + + align:start position:0% +you can + + + align:start position:0% +you can +do okay so this + + align:start position:0% +do okay so this + + + align:start position:0% +do okay so this +finishes part one question one and now + + align:start position:0% +finishes part one question one and now + + + align:start position:0% +finishes part one question one and now +let's move on to the more interesting + + align:start position:0% +let's move on to the more interesting + + + align:start position:0% +let's move on to the more interesting +and harder question + + align:start position:0% + + + + align:start position:0% + +two again let's start with some + + align:start position:0% +two again let's start with some + + + align:start position:0% +two again let's start with some +examples first here's + + align:start position:0% +examples first here's + + + align:start position:0% +examples first here's +a easy case if n is less than + + align:start position:0% +a easy case if n is less than + + + align:start position:0% +a easy case if n is less than +2K + + align:start position:0% +2K + + + align:start position:0% +2K +then okay so this is the easy setting if + + align:start position:0% +then okay so this is the easy setting if + + + align:start position:0% +then okay so this is the easy setting if +n is less than 2K then by pitching hole + + align:start position:0% +n is less than 2K then by pitching hole + + + align:start position:0% +n is less than 2K then by pitching hole +principle any pair of K element subsets + + align:start position:0% +principle any pair of K element subsets + + + align:start position:0% +principle any pair of K element subsets +of 1 through n intersect so we can take + + align:start position:0% +of 1 through n intersect so we can take + + + align:start position:0% +of 1 through n intersect so we can take +all n choose K + + align:start position:0% +all n choose K + + + align:start position:0% +all n choose K +sets and they form an + + align:start position:0% +sets and they form an + + + align:start position:0% +sets and they form an +intersecting family + + align:start position:0% + + + + align:start position:0% + +okay so there's nothing really to do + + align:start position:0% +okay so there's nothing really to do + + + align:start position:0% +okay so there's nothing really to do +here because we can just take all the K + + align:start position:0% +here because we can just take all the K + + + align:start position:0% +here because we can just take all the K +element + + align:start position:0% +element + + + align:start position:0% +element +sets so the harder part of the question + + align:start position:0% +sets so the harder part of the question + + + align:start position:0% +sets so the harder part of the question +the more interesting part is what + + align:start position:0% +the more interesting part is what + + + align:start position:0% +the more interesting part is what +happens when n is at least + + align:start position:0% +happens when n is at least + + + align:start position:0% +happens when n is at least +2K here as an + + align:start position:0% +2K here as an + + + align:start position:0% +2K here as an +example we can take as earlier all sets + + align:start position:0% + + + + align:start position:0% + +containing the element one + + align:start position:0% +containing the element one + + + align:start position:0% +containing the element one +and this gives us n minus one choose K + + align:start position:0% +and this gives us n minus one choose K + + + align:start position:0% +and this gives us n minus one choose K +minus one + + align:start position:0% +minus one + + + align:start position:0% +minus one +sets Okay and as before these sets they + + align:start position:0% +sets Okay and as before these sets they + + + align:start position:0% +sets Okay and as before these sets they +all this set form set this collection of + + align:start position:0% +all this set form set this collection of + + + align:start position:0% +all this set form set this collection of +sets form an intersecting family because + + align:start position:0% +sets form an intersecting family because + + + align:start position:0% +sets form an intersecting family because +any pair their intersection contains the + + align:start position:0% +any pair their intersection contains the + + + align:start position:0% +any pair their intersection contains the +element one and is thus + + align:start position:0% +element one and is thus + + + align:start position:0% +element one and is thus +nonempty right so this is a construction + + align:start position:0% +nonempty right so this is a construction + + + align:start position:0% +nonempty right so this is a construction +it gives you n minus1 choose K minus one + + align:start position:0% +it gives you n minus1 choose K minus one + + + align:start position:0% +it gives you n minus1 choose K minus one +sets but is this the best you can do + + align:start position:0% +sets but is this the best you can do + + + align:start position:0% +sets but is this the best you can do +right perhaps through some other methods + + align:start position:0% +right perhaps through some other methods + + + align:start position:0% +right perhaps through some other methods +of construction through other examples + + align:start position:0% +of construction through other examples + + + align:start position:0% +of construction through other examples +maybe there are even larger intersecting + + align:start position:0% +maybe there are even larger intersecting + + + align:start position:0% +maybe there are even larger intersecting +families of K element + + align:start position:0% +families of K element + + + align:start position:0% +families of K element +subsets that turns out not to be the + + align:start position:0% +subsets that turns out not to be the + + + align:start position:0% +subsets that turns out not to be the +case and that is the main theorem that + + align:start position:0% +case and that is the main theorem that + + + align:start position:0% +case and that is the main theorem that +we'll prove in this video and this + + align:start position:0% +we'll prove in this video and this + + + align:start position:0% +we'll prove in this video and this +result is known as the aish C rle + + align:start position:0% +result is known as the aish C rle + + + align:start position:0% +result is known as the aish C rle +theorem + + align:start position:0% + + + + align:start position:0% + +so this is a seminal and a beautiful + + align:start position:0% +so this is a seminal and a beautiful + + + align:start position:0% +so this is a seminal and a beautiful +result in extremal set + + align:start position:0% +result in extremal set + + + align:start position:0% +result in extremal set +theory and the ERS cor theorem says that + + align:start position:0% +theory and the ERS cor theorem says that + + + align:start position:0% +theory and the ERS cor theorem says that +if n is at least + + align:start position:0% +if n is at least + + + align:start position:0% +if n is at least +2K + + align:start position:0% + + + + align:start position:0% + +then + + align:start position:0% + + + + align:start position:0% + +any + + align:start position:0% +any + + + align:start position:0% +any +intersecting + + align:start position:0% +intersecting + + + align:start position:0% +intersecting +family and we give this family a name + + align:start position:0% +family and we give this family a name + + + align:start position:0% +family and we give this family a name +curly + + align:start position:0% +curly + + + align:start position:0% +curly +F of sub + + align:start position:0% + + + + align:start position:0% + +sets of 1 through + + align:start position:0% + + + + align:start position:0% + +n okay subsets um + + align:start position:0% +n okay subsets um + + + align:start position:0% +n okay subsets um +and any intersecting family of K element + + align:start position:0% + + + + align:start position:0% + +subsets of 1 through n + + align:start position:0% +subsets of 1 through n + + + align:start position:0% +subsets of 1 through n +has + + align:start position:0% +has + + + align:start position:0% +has +size at most n minus1 choose K minus + + align:start position:0% + + + + align:start position:0% + +one in other words the construction that + + align:start position:0% +one in other words the construction that + + + align:start position:0% +one in other words the construction that +we gave just now is indeed optimal you + + align:start position:0% +we gave just now is indeed optimal you + + + align:start position:0% +we gave just now is indeed optimal you +cannot get a bigger intersecting family + + align:start position:0% +cannot get a bigger intersecting family + + + align:start position:0% +cannot get a bigger intersecting family +of K element subsets of 1 through + + align:start position:0% + + + + align:start position:0% + +n let us now prove the erors corado + + align:start position:0% +n let us now prove the erors corado + + + align:start position:0% +n let us now prove the erors corado +theorem and we'll introduce Randomness + + align:start position:0% +theorem and we'll introduce Randomness + + + align:start position:0% +theorem and we'll introduce Randomness +into to the problem and use the uh use + + align:start position:0% +into to the problem and use the uh use + + + align:start position:0% +into to the problem and use the uh use +some beautiful ideas from the + + align:start position:0% +some beautiful ideas from the + + + align:start position:0% +some beautiful ideas from the +probabilistic + + align:start position:0% + + + + align:start position:0% + +method so here's how we start the + + align:start position:0% +method so here's how we start the + + + align:start position:0% +method so here's how we start the +proof let us + + align:start position:0% + + + + align:start position:0% + +order the numbers 1 2 3 and so on + + align:start position:0% +order the numbers 1 2 3 and so on + + + align:start position:0% +order the numbers 1 2 3 and so on +through n + + align:start position:0% +through n + + + align:start position:0% +through n +randomly around a + + align:start position:0% + + + + align:start position:0% + +circle okay so what do I mean by this + + align:start position:0% +circle okay so what do I mean by this + + + align:start position:0% +circle okay so what do I mean by this +take a + + align:start position:0% +take a + + + align:start position:0% +take a +circle and then basically take a uniform + + align:start position:0% +circle and then basically take a uniform + + + align:start position:0% +circle and then basically take a uniform +the random permutation of 1 through n + + align:start position:0% +the random permutation of 1 through n + + + align:start position:0% +the random permutation of 1 through n +and then place the + + align:start position:0% +and then place the + + + align:start position:0% +and then place the +numbers around the circle in the order + + align:start position:0% +numbers around the circle in the order + + + align:start position:0% +numbers around the circle in the order +of that permutation so for example I'm + + align:start position:0% +of that permutation so for example I'm + + + align:start position:0% +of that permutation so for example I'm +putting down nine numbers here n equal + + align:start position:0% +putting down nine numbers here n equal + + + align:start position:0% +putting down nine numbers here n equal +to 9 in some circular order chosen + + align:start position:0% +to 9 in some circular order chosen + + + align:start position:0% +to 9 in some circular order chosen +uniformly at random + + align:start position:0% + + + + align:start position:0% + +missing a number here six right so here + + align:start position:0% +missing a number here six right so here + + + align:start position:0% +missing a number here six right so here +nine numbers okay uniformly around the + + align:start position:0% +nine numbers okay uniformly around the + + + align:start position:0% +nine numbers okay uniformly around the +circle and let us + + align:start position:0% +circle and let us + + + align:start position:0% +circle and let us +call a + + align:start position:0% + + + + align:start position:0% + +set subset of 1 through + + align:start position:0% +set subset of 1 through + + + align:start position:0% +set subset of 1 through +n + + align:start position:0% +n + + + align:start position:0% +n +contiguous I'm here I'm + + align:start position:0% + + + + align:start position:0% + +defining term + + align:start position:0% +defining term + + + align:start position:0% +defining term +contiguous call this subset contigous us + + align:start position:0% +contiguous call this subset contigous us + + + align:start position:0% +contiguous call this subset contigous us +if its + + align:start position:0% + + + + align:start position:0% + +elements the way they're ordered around + + align:start position:0% +elements the way they're ordered around + + + align:start position:0% +elements the way they're ordered around +the circle form an + + align:start position:0% + + + + align:start position:0% + +arc in this + + align:start position:0% + + + + align:start position:0% + +ordering so for + + align:start position:0% +ordering so for + + + align:start position:0% +ordering so for +example the set of numbers 4 3 9 5 this + + align:start position:0% +example the set of numbers 4 3 9 5 this + + + align:start position:0% +example the set of numbers 4 3 9 5 this +Four Element set is + + align:start position:0% +Four Element set is + + + align:start position:0% +Four Element set is +contiguous so 3 4 5 9 is + + align:start position:0% + + + + align:start position:0% + +contiguous because the orders they're + + align:start position:0% +contiguous because the orders they're + + + align:start position:0% +contiguous because the orders they're +according to the circular ordering these + + align:start position:0% +according to the circular ordering these + + + align:start position:0% +according to the circular ordering these +four numbers form a contiguous block on + + align:start position:0% +four numbers form a contiguous block on + + + align:start position:0% +four numbers form a contiguous block on +the other hand the set 1 three is not + + align:start position:0% +the other hand the set 1 three is not + + + align:start position:0% +the other hand the set 1 three is not +contiguous because they do not form a + + align:start position:0% +contiguous because they do not form a + + + align:start position:0% +contiguous because they do not form a +contiguous + + align:start position:0% +contiguous + + + align:start position:0% +contiguous +block okay so that's just a + + align:start position:0% +block okay so that's just a + + + align:start position:0% +block okay so that's just a +definition and now for a + + align:start position:0% + + + + align:start position:0% + +given set sub a a subset of 1 through + + align:start position:0% +given set sub a a subset of 1 through + + + align:start position:0% +given set sub a a subset of 1 through +M + + align:start position:0% + + + + align:start position:0% + +with K + + align:start position:0% +with K + + + align:start position:0% +with K +elements so for a given K element subset + + align:start position:0% +elements so for a given K element subset + + + align:start position:0% +elements so for a given K element subset +of 1 through n what is the probability + + align:start position:0% +of 1 through n what is the probability + + + align:start position:0% +of 1 through n what is the probability +so here a is fixed a is not random so we + + align:start position:0% +so here a is fixed a is not random so we + + + align:start position:0% +so here a is fixed a is not random so we +given this a what is the probability + + align:start position:0% +given this a what is the probability + + + align:start position:0% +given this a what is the probability +that a is contiguous + + align:start position:0% + + + + align:start position:0% + +okay so the ordering Is Random so given + + align:start position:0% +okay so the ordering Is Random so given + + + align:start position:0% +okay so the ordering Is Random so given +a set what is the probability that under + + align:start position:0% +a set what is the probability that under + + + align:start position:0% +a set what is the probability that under +this random ordering is + + align:start position:0% +this random ordering is + + + align:start position:0% +this random ordering is +contiguous well let's think about + + align:start position:0% +contiguous well let's think about + + + align:start position:0% +contiguous well let's think about +that so the ordering is random but here + + align:start position:0% +that so the ordering is random but here + + + align:start position:0% +that so the ordering is random but here +if a has K elements can think about how + + align:start position:0% +if a has K elements can think about how + + + align:start position:0% +if a has K elements can think about how +many different ways these K elements can + + align:start position:0% +many different ways these K elements can + + + align:start position:0% +many different ways these K elements can +be placed around the circle + + align:start position:0% + + + + align:start position:0% + +there are n different + + align:start position:0% +there are n different + + + align:start position:0% +there are n different +positions from where geometrically this + + align:start position:0% +positions from where geometrically this + + + align:start position:0% +positions from where geometrically this +K length K Arc lies and once you fix + + align:start position:0% +K length K Arc lies and once you fix + + + align:start position:0% +K length K Arc lies and once you fix +that + + align:start position:0% +that + + + align:start position:0% +that +position the + + align:start position:0% +position the + + + align:start position:0% +position the +probability + + align:start position:0% +probability + + + align:start position:0% +probability +that the elements the K elements of a + + align:start position:0% +that the elements the K elements of a + + + align:start position:0% +that the elements the K elements of a +actually falls into the desired + + align:start position:0% +actually falls into the desired + + + align:start position:0% +actually falls into the desired +positions + + align:start position:0% +positions + + + align:start position:0% +positions +is 1/ K one over and choose + + align:start position:0% + + + + align:start position:0% + +K okay so this is the probability that a + + align:start position:0% +K okay so this is the probability that a + + + align:start position:0% +K okay so this is the probability that a +is a contiguous set under this random + + align:start position:0% +is a contiguous set under this random + + + align:start position:0% +is a contiguous set under this random +ordering and + + align:start position:0% +ordering and + + + align:start position:0% +ordering and +now by the linearity of + + align:start position:0% +now by the linearity of + + + align:start position:0% +now by the linearity of +expectations the expected number of + + align:start position:0% + + + + align:start position:0% + +contiguous sets + + align:start position:0% + + + + align:start position:0% + +in this collection + + align:start position:0% +in this collection + + + align:start position:0% +in this collection +f is equal to the size of f times the + + align:start position:0% +f is equal to the size of f times the + + + align:start position:0% +f is equal to the size of f times the +probability that each individual set is + + align:start position:0% +probability that each individual set is + + + align:start position:0% +probability that each individual set is +contiguous and that was calculated + + align:start position:0% +contiguous and that was calculated + + + align:start position:0% +contiguous and that was calculated +earlier to be this quantity so n / n + + align:start position:0% +earlier to be this quantity so n / n + + + align:start position:0% +earlier to be this quantity so n / n +choose + + align:start position:0% + + + + align:start position:0% + +K on the other hand + + align:start position:0% + + + + align:start position:0% + +the property of f being + + align:start position:0% + + + + align:start position:0% + +intersecting a claim implies that in any + + align:start position:0% +intersecting a claim implies that in any + + + align:start position:0% +intersecting a claim implies that in any +given circular ordering there are at + + align:start position:0% +given circular ordering there are at + + + align:start position:0% +given circular ordering there are at +most K + + align:start position:0% + + + + align:start position:0% + +contiguous + + align:start position:0% + + + + align:start position:0% + +sets + + align:start position:0% +sets + + + align:start position:0% +sets +for so in a + + align:start position:0% +for so in a + + + align:start position:0% +for so in a +given circular ordering okay so let's + + align:start position:0% +given circular ordering okay so let's + + + align:start position:0% +given circular ordering okay so let's +pause and think about why this claim is + + align:start position:0% +pause and think about why this claim is + + + align:start position:0% +pause and think about why this claim is +true if I give you an + + align:start position:0% +true if I give you an + + + align:start position:0% +true if I give you an +ordering and ask well how many + + align:start position:0% +ordering and ask well how many + + + align:start position:0% +ordering and ask well how many +contiguous sets can there be and now + + align:start position:0% +contiguous sets can there be and now + + + align:start position:0% +contiguous sets can there be and now +this sets these contiguous sets they + + align:start position:0% +this sets these contiguous sets they + + + align:start position:0% +this sets these contiguous sets they +have to be intersecting right so if we + + align:start position:0% +have to be intersecting right so if we + + + align:start position:0% +have to be intersecting right so if we +have one set so here let me denote the + + align:start position:0% +have one set so here let me denote the + + + align:start position:0% +have one set so here let me denote the +elements these circles as think about + + align:start position:0% +elements these circles as think about + + + align:start position:0% +elements these circles as think about +them as positions on the circle so these + + align:start position:0% +them as positions on the circle so these + + + align:start position:0% +them as positions on the circle so these +dots as positions on the circle so if + + align:start position:0% +dots as positions on the circle so if + + + align:start position:0% +dots as positions on the circle so if +that's one set well where can the other + + align:start position:0% +that's one set well where can the other + + + align:start position:0% +that's one set well where can the other +sets be well they have to intersect this + + align:start position:0% +sets be well they have to intersect this + + + align:start position:0% +sets be well they have to intersect this +block so maybe another set is like this + + align:start position:0% +block so maybe another set is like this + + + align:start position:0% +block so maybe another set is like this +one but if that set is in then it + + align:start position:0% +one but if that set is in then it + + + align:start position:0% +one but if that set is in then it +excludes if this blue set is in then + + align:start position:0% +excludes if this blue set is in then + + + align:start position:0% +excludes if this blue set is in then +excludes this green set from a + + align:start position:0% +excludes this green set from a + + + align:start position:0% +excludes this green set from a +possibility and so + + align:start position:0% + + + + align:start position:0% + +on right + + align:start position:0% + + + + align:start position:0% + +and okay so you see that given that this + + align:start position:0% +and okay so you see that given that this + + + align:start position:0% +and okay so you see that given that this +red set is + + align:start position:0% +red set is + + + align:start position:0% +red set is +in well at most one of the blue and + + align:start position:0% +in well at most one of the blue and + + + align:start position:0% +in well at most one of the blue and +green on the second line can be in and + + align:start position:0% +green on the second line can be in and + + + align:start position:0% +green on the second line can be in and +the most one of the blue and green on + + align:start position:0% +the most one of the blue and green on + + + align:start position:0% +the most one of the blue and green on +the third line can be in and the most + + align:start position:0% +the third line can be in and the most + + + align:start position:0% +the third line can be in and the most +one of blue and green on the fourth line + + align:start position:0% +one of blue and green on the fourth line + + + align:start position:0% +one of blue and green on the fourth line +can be in and these are the all the + + align:start position:0% +can be in and these are the all the + + + align:start position:0% +can be in and these are the all the +possibilities of how another contiguous + + align:start position:0% +possibilities of how another contiguous + + + align:start position:0% +possibilities of how another contiguous +set can intersect the the red set so + + align:start position:0% +set can intersect the the red set so + + + align:start position:0% +set can intersect the the red set so +that's an argument that can translate + + align:start position:0% +that's an argument that can translate + + + align:start position:0% +that's an argument that can translate +into this claim that F being + + align:start position:0% +into this claim that F being + + + align:start position:0% +into this claim that F being +intersecting implies that most K + + align:start position:0% +intersecting implies that most K + + + align:start position:0% +intersecting implies that most K +contiguous sets in any given + + align:start position:0% +contiguous sets in any given + + + align:start position:0% +contiguous sets in any given +order okay so this argument is very + + align:start position:0% +order okay so this argument is very + + + align:start position:0% +order okay so this argument is very +analog to the argument that we did at + + align:start position:0% +analog to the argument that we did at + + + align:start position:0% +analog to the argument that we did at +the beginning where we pair up + + align:start position:0% +the beginning where we pair up + + + align:start position:0% +the beginning where we pair up +complimentary sets but this time we're + + align:start position:0% +complimentary sets but this time we're + + + align:start position:0% +complimentary sets but this time we're +only looking at contiguous sets that + + align:start position:0% +only looking at contiguous sets that + + + align:start position:0% +only looking at contiguous sets that +intersect a given + + align:start position:0% +intersect a given + + + align:start position:0% +intersect a given +set + + align:start position:0% +set + + + align:start position:0% +set +okay well if you can only get at most K + + align:start position:0% +okay well if you can only get at most K + + + align:start position:0% +okay well if you can only get at most K +contiguous sets in any given order then + + align:start position:0% +contiguous sets in any given order then + + + align:start position:0% +contiguous sets in any given order then +this quantity which is a random variable + + align:start position:0% +this quantity which is a random variable + + + align:start position:0% +this quantity which is a random variable +it is always at most + + align:start position:0% + + + + align:start position:0% + +K so in it's expectation then this + + align:start position:0% +K so in it's expectation then this + + + align:start position:0% +K so in it's expectation then this +quantity that we got at the end is also + + align:start position:0% +quantity that we got at the end is also + + + align:start position:0% +quantity that we got at the end is also +at + + align:start position:0% +at + + + align:start position:0% +at +most + + align:start position:0% + + + + align:start position:0% + +K + + align:start position:0% +K + + + align:start position:0% +K +thus the size of f is at most K Over N + + align:start position:0% +thus the size of f is at most K Over N + + + align:start position:0% +thus the size of f is at most K Over N +time n chose + + align:start position:0% +time n chose + + + align:start position:0% +time n chose +K which one can then expand the binomial + + align:start position:0% +K which one can then expand the binomial + + + align:start position:0% +K which one can then expand the binomial +coefficient to see that the final + + align:start position:0% +coefficient to see that the final + + + align:start position:0% +coefficient to see that the final +quantity is equal to nus1 choose K -1 + + align:start position:0% +quantity is equal to nus1 choose K -1 + + + align:start position:0% +quantity is equal to nus1 choose K -1 +one and that's exactly what we + + align:start position:0% + + + + align:start position:0% + +claimed all right so this finishes the + + align:start position:0% +claimed all right so this finishes the + + + align:start position:0% +claimed all right so this finishes the +proof of the ERS corado theorem which is + + align:start position:0% +proof of the ERS corado theorem which is + + + align:start position:0% +proof of the ERS corado theorem which is +a foundational result in extremal set + + align:start position:0% +a foundational result in extremal set + + + align:start position:0% +a foundational result in extremal set +theory and it's a beautiful application + + align:start position:0% +theory and it's a beautiful application + + + align:start position:0% +theory and it's a beautiful application +of the probabilistic method to extremal + + align:start position:0% +of the probabilistic method to extremal + + + align:start position:0% +of the probabilistic method to extremal +set theory and to combinatorics in + + align:start position:0% +set theory and to combinatorics in + + + align:start position:0% +set theory and to combinatorics in +general where we start with a claim a + + align:start position:0% +general where we start with a claim a + + + align:start position:0% +general where we start with a claim a +theorem that is not random at all it is + + align:start position:0% +theorem that is not random at all it is + + + align:start position:0% +theorem that is not random at all it is +completely deterministic it's about + + align:start position:0% +completely deterministic it's about + + + align:start position:0% +completely deterministic it's about +finding the maximum possible set size + + align:start position:0% +finding the maximum possible set size + + + align:start position:0% +finding the maximum possible set size +the size of something that satisfies + + align:start position:0% +the size of something that satisfies + + + align:start position:0% +the size of something that satisfies +some constraints and yet the proof goes + + align:start position:0% +some constraints and yet the proof goes + + + align:start position:0% +some constraints and yet the proof goes +by introducing new Randomness into the + + align:start position:0% +by introducing new Randomness into the + + + align:start position:0% +by introducing new Randomness into the +setup that allows us then to derive this + + align:start position:0% +setup that allows us then to derive this + + + align:start position:0% +setup that allows us then to derive this +beautiful conclusion \ No newline at end of file diff --git a/ziViLYrf1Ak.txt b/ziViLYrf1Ak.txt new file mode 100644 index 0000000000000000000000000000000000000000..387bc649ad7acfe7400d95ddb933f0c15c60630c --- /dev/null +++ b/ziViLYrf1Ak.txt @@ -0,0 +1,15075 @@ +align:start position:0% + +The following content is provided under + + align:start position:0% +The following content is provided under + + + align:start position:0% +The following content is provided under +a Creative Common License. Your support + + align:start position:0% +a Creative Common License. Your support + + + align:start position:0% +a Creative Common License. Your support +will help MIT Open Courseware continue + + align:start position:0% +will help MIT Open Courseware continue + + + align:start position:0% +will help MIT Open Courseware continue +to offer highquality educational + + align:start position:0% +to offer highquality educational + + + align:start position:0% +to offer highquality educational +resources for free. To make a donation + + align:start position:0% +resources for free. To make a donation + + + align:start position:0% +resources for free. To make a donation +or to view additional materials from + + align:start position:0% +or to view additional materials from + + + align:start position:0% +or to view additional materials from +hundreds of MIT courses, visit MIT Open + + align:start position:0% +hundreds of MIT courses, visit MIT Open + + + align:start position:0% +hundreds of MIT courses, visit MIT Open +Courseware at ocw.mmit.edu. + + align:start position:0% + + + + align:start position:0% + +All right, welcome back to 6890. Uh + + align:start position:0% +All right, welcome back to 6890. Uh + + + align:start position:0% +All right, welcome back to 6890. Uh +today will be our last lecture about + + align:start position:0% +today will be our last lecture about + + + align:start position:0% +today will be our last lecture about +pure thresat so to speak and we'll be + + align:start position:0% +pure thresat so to speak and we'll be + + + align:start position:0% +pure thresat so to speak and we'll be +focusing in particular on circuit sat + + align:start position:0% +focusing in particular on circuit sat + + + align:start position:0% +focusing in particular on circuit sat +today. Um but before we get started with + + align:start position:0% +today. Um but before we get started with + + + align:start position:0% +today. Um but before we get started with +more reductions I want to highlight uh + + align:start position:0% +more reductions I want to highlight uh + + + align:start position:0% +more reductions I want to highlight uh +two styles of threes proofs that we've + + align:start position:0% +two styles of threes proofs that we've + + + align:start position:0% +two styles of threes proofs that we've +seen. Um this sort of this is orthogonal + + align:start position:0% +seen. Um this sort of this is orthogonal + + + align:start position:0% +seen. Um this sort of this is orthogonal +to the circuit perspective versus uh + + align:start position:0% +to the circuit perspective versus uh + + + align:start position:0% +to the circuit perspective versus uh +logic perspective. Um, so I think and I + + align:start position:0% +logic perspective. Um, so I think and I + + + align:start position:0% +logic perspective. Um, so I think and I +think it's interesting to highlight the + + align:start position:0% +think it's interesting to highlight the + + + align:start position:0% +think it's interesting to highlight the +two different approaches. + + align:start position:0% +two different approaches. + + + align:start position:0% +two different approaches. +So approach one I'm going to call dual + + align:start position:0% +So approach one I'm going to call dual + + + align:start position:0% +So approach one I'm going to call dual +rail logic. + + align:start position:0% +rail logic. + + + align:start position:0% +rail logic. +These are not the usual names. We're + + align:start position:0% +These are not the usual names. We're + + + align:start position:0% +These are not the usual names. We're +making up names here. There aren't + + align:start position:0% +making up names here. There aren't + + + align:start position:0% +making up names here. There aren't +really names for these types of + + align:start position:0% +really names for these types of + + + align:start position:0% +really names for these types of +reductions. And the other type I'm going + + align:start position:0% +reductions. And the other type I'm going + + + align:start position:0% +reductions. And the other type I'm going +to call binary logic. + + align:start position:0% + + + + align:start position:0% + +These names come from uh actual circuit + + align:start position:0% +These names come from uh actual circuit + + + align:start position:0% +These names come from uh actual circuit +stuff, real hardware. Um so for example, + + align:start position:0% +stuff, real hardware. Um so for example, + + + align:start position:0% +stuff, real hardware. Um so for example, +the all the Nintendo proofs we saw are + + align:start position:0% +the all the Nintendo proofs we saw are + + + align:start position:0% +the all the Nintendo proofs we saw are +in the style of what I would call dual + + align:start position:0% +in the style of what I would call dual + + + align:start position:0% +in the style of what I would call dual +rail logic because the variables have + + align:start position:0% +rail logic because the variables have + + + align:start position:0% +rail logic because the variables have +two outputs. The idea is that this one + + align:start position:0% +two outputs. The idea is that this one + + + align:start position:0% +two outputs. The idea is that this one +is activated when X is set to true. This + + align:start position:0% +is activated when X is set to true. This + + + align:start position:0% +is activated when X is set to true. This +one is activated when not X is set to + + align:start position:0% +one is activated when not X is set to + + + align:start position:0% +one is activated when not X is set to +true or X is set to false. Uh never + + align:start position:0% +true or X is set to false. Uh never + + + align:start position:0% +true or X is set to false. Uh never +should both of them be activated. So you + + align:start position:0% +should both of them be activated. So you + + + align:start position:0% +should both of them be activated. So you +have a separate rail, a separate line + + align:start position:0% +have a separate rail, a separate line + + + align:start position:0% +have a separate rail, a separate line +for the true case and a separate line + + align:start position:0% +for the true case and a separate line + + + align:start position:0% +for the true case and a separate line +for the false case. So and this is + + align:start position:0% +for the false case. So and this is + + + align:start position:0% +for the false case. So and this is +usually called the variable gadget that + + align:start position:0% +usually called the variable gadget that + + + align:start position:0% +usually called the variable gadget that +does that. + + align:start position:0% + + + + align:start position:0% + +And I'm going to make up some more + + align:start position:0% +And I'm going to make up some more + + + align:start position:0% +And I'm going to make up some more +terminology. I'll call these semiwires. + + align:start position:0% +terminology. I'll call these semiwires. + + + align:start position:0% +terminology. I'll call these semiwires. +to distinguish from wires. + + align:start position:0% +to distinguish from wires. + + + align:start position:0% +to distinguish from wires. +Um so over here in the binary logic case + + align:start position:0% + + + + align:start position:0% + +this is sort of a half of a distinction. + + align:start position:0% +this is sort of a half of a distinction. + + + align:start position:0% +this is sort of a half of a distinction. +It's a semi- distinction. So um + + align:start position:0% + + + + align:start position:0% + +but this is my attempt to unify things + + align:start position:0% +but this is my attempt to unify things + + + align:start position:0% +but this is my attempt to unify things +slightly. Uh so we have um + + align:start position:0% +slightly. Uh so we have um + + + align:start position:0% +slightly. Uh so we have um +yeah so so the idea is that these + + align:start position:0% +yeah so so the idea is that these + + + align:start position:0% +yeah so so the idea is that these +semiwires either they get activated or + + align:start position:0% +semiwires either they get activated or + + + align:start position:0% +semiwires either they get activated or +they don't get activated at all. Um in + + align:start position:0% +they don't get activated at all. Um in + + + align:start position:0% +they don't get activated at all. Um in +the unactivated case they're I mean + + align:start position:0% +the unactivated case they're I mean + + + align:start position:0% +the unactivated case they're I mean +there nothing happens to them. So uh + + align:start position:0% +there nothing happens to them. So uh + + + align:start position:0% +there nothing happens to them. So uh +they're not really interesting in the + + align:start position:0% +they're not really interesting in the + + + align:start position:0% +they're not really interesting in the +binary logic case. The idea is that the + + align:start position:0% +binary logic case. The idea is that the + + + align:start position:0% +binary logic case. The idea is that the +wire gadget is active in all situations + + align:start position:0% +wire gadget is active in all situations + + + align:start position:0% +wire gadget is active in all situations +but it can be active in two different + + align:start position:0% +but it can be active in two different + + + align:start position:0% +but it can be active in two different +ways. You can either set it to the true + + align:start position:0% +ways. You can either set it to the true + + + align:start position:0% +ways. You can either set it to the true +state or you can set it to the false + + align:start position:0% +state or you can set it to the false + + + align:start position:0% +state or you can set it to the false +state and it represents both sort of in + + align:start position:0% +state and it represents both sort of in + + + align:start position:0% +state and it represents both sort of in +one wire. Now this distinction is going + + align:start position:0% +one wire. Now this distinction is going + + + align:start position:0% +one wire. Now this distinction is going +to get a little bit vague but we saw an + + align:start position:0% +to get a little bit vague but we saw an + + + align:start position:0% +to get a little bit vague but we saw an +example of this kind of proof uh when we + + align:start position:0% +example of this kind of proof uh when we + + + align:start position:0% +example of this kind of proof uh when we +were talking about crease pattern flat + + align:start position:0% +were talking about crease pattern flat + + + align:start position:0% +were talking about crease pattern flat +foldability and P hardness. Uh the wire + + align:start position:0% +foldability and P hardness. Uh the wire + + + align:start position:0% +foldability and P hardness. Uh the wire +was the pleat and the pleat could be + + align:start position:0% +was the pleat and the pleat could be + + + align:start position:0% +was the pleat and the pleat could be +folded one way or the other. Uh but + + align:start position:0% +folded one way or the other. Uh but + + + align:start position:0% +folded one way or the other. Uh but +either way the the information is right + + align:start position:0% +either way the the information is right + + + align:start position:0% +either way the the information is right +here and it this the same wire gets put + + align:start position:0% +here and it this the same wire gets put + + + align:start position:0% +here and it this the same wire gets put +into this gadget whether you're true or + + align:start position:0% +into this gadget whether you're true or + + + align:start position:0% +into this gadget whether you're true or +false. Okay. Whereas over here + + align:start position:0% +false. Okay. Whereas over here + + + align:start position:0% +false. Okay. Whereas over here +uh you're connecting to this clause only + + align:start position:0% +uh you're connecting to this clause only + + + align:start position:0% +uh you're connecting to this clause only +the true uh half wire or semiwire goes + + align:start position:0% +the true uh half wire or semiwire goes + + + align:start position:0% +the true uh half wire or semiwire goes +to this clause. Uh the false one goes to + + align:start position:0% +to this clause. Uh the false one goes to + + + align:start position:0% +to this clause. Uh the false one goes to +this clause and to this clause. Okay. So + + align:start position:0% +this clause and to this clause. Okay. So + + + align:start position:0% +this clause and to this clause. Okay. So +there's a distinction between here where + + align:start position:0% +there's a distinction between here where + + + align:start position:0% +there's a distinction between here where +the wire has been split in half and here + + align:start position:0% +the wire has been split in half and here + + + align:start position:0% +the wire has been split in half and here +where it's all in one place and the wire + + align:start position:0% +where it's all in one place and the wire + + + align:start position:0% +where it's all in one place and the wire +goes to the gadget whether it said true + + align:start position:0% +goes to the gadget whether it said true + + + align:start position:0% +goes to the gadget whether it said true +or false. Um I think that's sort of what + + align:start position:0% +or false. Um I think that's sort of what + + + align:start position:0% +or false. Um I think that's sort of what +I wanted to say. My main intent here is + + align:start position:0% +I wanted to say. My main intent here is + + + align:start position:0% +I wanted to say. My main intent here is +to highlight what kind of gadgets you + + align:start position:0% +to highlight what kind of gadgets you + + + align:start position:0% +to highlight what kind of gadgets you +need. So + + align:start position:0% +need. So + + + align:start position:0% +need. So +uh we have a wire gadget on this side, a + + align:start position:0% +uh we have a wire gadget on this side, a + + + align:start position:0% +uh we have a wire gadget on this side, a +variable gadget on this side. Uh for + + align:start position:0% +variable gadget on this side. Uh for + + + align:start position:0% +variable gadget on this side. Uh for +binary logic, you also need a splitter + + align:start position:0% +binary logic, you also need a splitter + + + align:start position:0% +binary logic, you also need a splitter +or split gadget + + align:start position:0% +or split gadget + + + align:start position:0% +or split gadget +to make copies of the wire. + + align:start position:0% + + + + align:start position:0% + +So the idea is you have one wire coming + + align:start position:0% +So the idea is you have one wire coming + + + align:start position:0% +So the idea is you have one wire coming +in. There's some magic split gadget + + align:start position:0% +in. There's some magic split gadget + + + align:start position:0% +in. There's some magic split gadget +which makes two wires or three wires + + align:start position:0% +which makes two wires or three wires + + + align:start position:0% +which makes two wires or three wires +whatever uh coming out. So then you can + + align:start position:0% +whatever uh coming out. So then you can + + + align:start position:0% +whatever uh coming out. So then you can +repeat split however many times that + + align:start position:0% +repeat split however many times that + + + align:start position:0% +repeat split however many times that +variable occurs. um you can uh make a + + align:start position:0% +variable occurs. um you can uh make a + + + align:start position:0% +variable occurs. um you can uh make a +copy in the non-monotone versions of + + align:start position:0% +copy in the non-monotone versions of + + + align:start position:0% +copy in the non-monotone versions of +threes. You may also need uh a negation + + align:start position:0% +threes. You may also need uh a negation + + + align:start position:0% +threes. You may also need uh a negation +or not gadget. + + align:start position:0% +or not gadget. + + + align:start position:0% +or not gadget. +If you need negation, then you'll need a + + align:start position:0% +If you need negation, then you'll need a + + + align:start position:0% +If you need negation, then you'll need a +negation gadget. Um in some cases, you + + align:start position:0% +negation gadget. Um in some cases, you + + + align:start position:0% +negation gadget. Um in some cases, you +also need uh a terminator gadget. + + align:start position:0% +also need uh a terminator gadget. + + + align:start position:0% +also need uh a terminator gadget. +In this perspective, + + align:start position:0% + + + + align:start position:0% + +terminator gadget uh + + align:start position:0% + + + + align:start position:0% + +is just uh the end of a wire, you might + + align:start position:0% +is just uh the end of a wire, you might + + + align:start position:0% +is just uh the end of a wire, you might +say. So if you want to just not use a + + align:start position:0% +say. So if you want to just not use a + + + align:start position:0% +say. So if you want to just not use a +wire, then that's uh you would put a + + align:start position:0% +wire, then that's uh you would put a + + + align:start position:0% +wire, then that's uh you would put a +terminator gadget. And the idea of the + + align:start position:0% +terminator gadget. And the idea of the + + + align:start position:0% +terminator gadget. And the idea of the +terminator gadget is it leaves it free. + + align:start position:0% +terminator gadget is it leaves it free. + + + align:start position:0% +terminator gadget is it leaves it free. +Leaves the wire free to choose true or + + align:start position:0% +Leaves the wire free to choose true or + + + align:start position:0% +Leaves the wire free to choose true or +false. Uh now sometimes you can get away + + align:start position:0% +false. Uh now sometimes you can get away + + + align:start position:0% +false. Uh now sometimes you can get away +without a terminator gadget if uh you + + align:start position:0% +without a terminator gadget if uh you + + + align:start position:0% +without a terminator gadget if uh you +can for example if each of your + + align:start position:0% +can for example if each of your + + + align:start position:0% +can for example if each of your +variables occurs exactly four times uh + + align:start position:0% +variables occurs exactly four times uh + + + align:start position:0% +variables occurs exactly four times uh +then you can just use two splitters make + + align:start position:0% +then you can just use two splitters make + + + align:start position:0% +then you can just use two splitters make +four copies and then connect those + + align:start position:0% +four copies and then connect those + + + align:start position:0% +four copies and then connect those +directly to the clauses. So maybe with + + align:start position:0% +directly to the clauses. So maybe with + + + align:start position:0% +directly to the clauses. So maybe with +some negations. So in that case you + + align:start position:0% +some negations. So in that case you + + + align:start position:0% +some negations. So in that case you +wouldn't need a terminator. Uh over here + + align:start position:0% +wouldn't need a terminator. Uh over here + + + align:start position:0% +wouldn't need a terminator. Uh over here +we're using a terminator in a certain + + align:start position:0% +we're using a terminator in a certain + + + align:start position:0% +we're using a terminator in a certain +sense which is the edge of the paper. If + + align:start position:0% +sense which is the edge of the paper. If + + + align:start position:0% +sense which is the edge of the paper. If +a wire goes to the edge of the paper it + + align:start position:0% +a wire goes to the edge of the paper it + + + align:start position:0% +a wire goes to the edge of the paper it +becomes free. Uh so that sort of the + + align:start position:0% +becomes free. Uh so that sort of the + + + align:start position:0% +becomes free. Uh so that sort of the +terminator gadget here although we + + align:start position:0% +terminator gadget here although we + + + align:start position:0% +terminator gadget here although we +didn't make it explicit it was part of + + align:start position:0% +didn't make it explicit it was part of + + + align:start position:0% +didn't make it explicit it was part of +this uh overall plan. + + align:start position:0% +this uh overall plan. + + + align:start position:0% +this uh overall plan. +Uh + + align:start position:0% +Uh + + + align:start position:0% +Uh +in both cases + + align:start position:0% +in both cases + + + align:start position:0% +in both cases +in one and two + + align:start position:0% +in one and two + + + align:start position:0% +in one and two +you probably need something like a turn + + align:start position:0% +you probably need something like a turn + + + align:start position:0% +you probably need something like a turn +gadget + + align:start position:0% + + + + align:start position:0% + +and maybe a crossover gadget. + + align:start position:0% + + + + align:start position:0% + +And we've seen we've seen these in + + align:start position:0% +And we've seen we've seen these in + + + align:start position:0% +And we've seen we've seen these in +various forms. In this case, the turn + + align:start position:0% +various forms. In this case, the turn + + + align:start position:0% +various forms. In this case, the turn +gadget was very explicit. Uh I mean it + + align:start position:0% +gadget was very explicit. Uh I mean it + + + align:start position:0% +gadget was very explicit. Uh I mean it +was also a splitter and also a negator, + + align:start position:0% +was also a splitter and also a negator, + + + align:start position:0% +was also a splitter and also a negator, +but in particular it changed the angle. + + align:start position:0% +but in particular it changed the angle. + + + align:start position:0% +but in particular it changed the angle. +And we needed that in order to take this + + align:start position:0% +And we needed that in order to take this + + + align:start position:0% +And we needed that in order to take this +truth value and send it up to the clause + + align:start position:0% +truth value and send it up to the clause + + + align:start position:0% +truth value and send it up to the clause +and aim everything, right? + + align:start position:0% +and aim everything, right? + + + align:start position:0% +and aim everything, right? +Uh, and in general, if you're doing any + + align:start position:0% +Uh, and in general, if you're doing any + + + align:start position:0% +Uh, and in general, if you're doing any +kind of embedding into two dimensions, + + align:start position:0% +kind of embedding into two dimensions, + + + align:start position:0% +kind of embedding into two dimensions, +you're probably going to need a turn + + align:start position:0% +you're probably going to need a turn + + + align:start position:0% +you're probably going to need a turn +gadget so you can move your wires or + + align:start position:0% +gadget so you can move your wires or + + + align:start position:0% +gadget so you can move your wires or +semi-wires around. Um, most a lot of the + + align:start position:0% +semi-wires around. Um, most a lot of the + + + align:start position:0% +semi-wires around. Um, most a lot of the +time people might call this also a wire. + + align:start position:0% +time people might call this also a wire. + + + align:start position:0% +time people might call this also a wire. +So, that's why uh, but I think it's + + align:start position:0% +So, that's why uh, but I think it's + + + align:start position:0% +So, that's why uh, but I think it's +useful to have a word to distinguish + + align:start position:0% +useful to have a word to distinguish + + + align:start position:0% +useful to have a word to distinguish +these kinds of wires which are only + + align:start position:0% +these kinds of wires which are only + + + align:start position:0% +these kinds of wires which are only +active or inactive versus the wires + + align:start position:0% +active or inactive versus the wires + + + align:start position:0% +active or inactive versus the wires +which are always active but in two + + align:start position:0% +which are always active but in two + + + align:start position:0% +which are always active but in two +possible states. + + align:start position:0% +possible states. + + + align:start position:0% +possible states. +Hopefully that's that clarifies or makes + + align:start position:0% +Hopefully that's that clarifies or makes + + + align:start position:0% +Hopefully that's that clarifies or makes +more explicit the types of proofs we've + + align:start position:0% +more explicit the types of proofs we've + + + align:start position:0% +more explicit the types of proofs we've +seen so far. Um now today we're going to + + align:start position:0% +seen so far. Um now today we're going to + + + align:start position:0% +seen so far. Um now today we're going to +do a couple of circuit sat proofs which + + align:start position:0% +do a couple of circuit sat proofs which + + + align:start position:0% +do a couple of circuit sat proofs which +all of this applies to circuit SAT + + align:start position:0% +all of this applies to circuit SAT + + + align:start position:0% +all of this applies to circuit SAT +proofs as well as SAT and one and three + + align:start position:0% +proofs as well as SAT and one and three + + + align:start position:0% +proofs as well as SAT and one and three +sat and not all equals SAT not all equal + + align:start position:0% +sat and not all equals SAT not all equal + + + align:start position:0% +sat and not all equals SAT not all equal +threes. um circuit set you're going to + + align:start position:0% +threes. um circuit set you're going to + + + align:start position:0% +threes. um circuit set you're going to +have I guess in principle you could do + + align:start position:0% +have I guess in principle you could do + + + align:start position:0% +have I guess in principle you could do +it uh dual rail logic or binary logic + + align:start position:0% +it uh dual rail logic or binary logic + + + align:start position:0% +it uh dual rail logic or binary logic +although usually we probably think of + + align:start position:0% +although usually we probably think of + + + align:start position:0% +although usually we probably think of +them in this capacity um in binary logic + + align:start position:0% +them in this capacity um in binary logic + + + align:start position:0% +them in this capacity um in binary logic +and you're going to have wires you still + + align:start position:0% +and you're going to have wires you still + + + align:start position:0% +and you're going to have wires you still +need splits because you need to be able + + align:start position:0% +need splits because you need to be able + + + align:start position:0% +need splits because you need to be able +to take the output of a gate and send it + + align:start position:0% +to take the output of a gate and send it + + + align:start position:0% +to take the output of a gate and send it +to multiple other gates um in addition + + align:start position:0% +to multiple other gates um in addition + + + align:start position:0% +to multiple other gates um in addition +to a not gadget you're going to want + + align:start position:0% +to a not gadget you're going to want + + + align:start position:0% +to a not gadget you're going to want +some other universal uh logic gate + + align:start position:0% +some other universal uh logic gate + + + align:start position:0% +some other universal uh logic gate +So we're going to talk about that in a + + align:start position:0% +So we're going to talk about that in a + + + align:start position:0% +So we're going to talk about that in a +bit after we see some examples. + + align:start position:0% +bit after we see some examples. + + + align:start position:0% +bit after we see some examples. +So our first example + + align:start position:0% +So our first example + + + align:start position:0% +So our first example +is called Akari or light up. Uh this is + + align:start position:0% +is called Akari or light up. Uh this is + + + align:start position:0% +is called Akari or light up. Uh this is +another nicoli puzzle like Sudoku and uh + + align:start position:0% +another nicoli puzzle like Sudoku and uh + + + align:start position:0% +another nicoli puzzle like Sudoku and uh +uh number link we saw last time. Uh so + + align:start position:0% +uh number link we saw last time. Uh so + + + align:start position:0% +uh number link we saw last time. Uh so +here's the sample input and a sample + + align:start position:0% +here's the sample input and a sample + + + align:start position:0% +here's the sample input and a sample +output. Uh ignore the black dots there. + + align:start position:0% +output. Uh ignore the black dots there. + + + align:start position:0% +output. Uh ignore the black dots there. +So, uh, you're given a grid. Uh, there's + + align:start position:0% +So, uh, you're given a grid. Uh, there's + + + align:start position:0% +So, uh, you're given a grid. Uh, there's +blank squares and there's obstacle + + align:start position:0% +blank squares and there's obstacle + + + align:start position:0% +blank squares and there's obstacle +squares where you're not allowed to put + + align:start position:0% +squares where you're not allowed to put + + + align:start position:0% +squares where you're not allowed to put +anything. Some of the obstacle squares + + align:start position:0% +anything. Some of the obstacle squares + + + align:start position:0% +anything. Some of the obstacle squares +may have a number between zero and four + + align:start position:0% +may have a number between zero and four + + + align:start position:0% +may have a number between zero and four +on them. And that number represents how + + align:start position:0% +on them. And that number represents how + + + align:start position:0% +on them. And that number represents how +many among the four neighbors, edge + + align:start position:0% +many among the four neighbors, edge + + + align:start position:0% +many among the four neighbors, edge +neighbors of that square, how many of + + align:start position:0% +neighbors of that square, how many of + + + align:start position:0% +neighbors of that square, how many of +them should have a light. These blue + + align:start position:0% +them should have a light. These blue + + + align:start position:0% +them should have a light. These blue +circles are lights. Okay? So, like this + + align:start position:0% +circles are lights. Okay? So, like this + + + align:start position:0% +circles are lights. Okay? So, like this +one has zero lights in those four + + align:start position:0% +one has zero lights in those four + + + align:start position:0% +one has zero lights in those four +positions. This one has two. This one + + align:start position:0% +positions. This one has two. This one + + + align:start position:0% +positions. This one has two. This one +has four. That's forced. and so on. A + + align:start position:0% +has four. That's forced. and so on. A + + + align:start position:0% +has four. That's forced. and so on. A +lot of the cells are free, but whether + + align:start position:0% +lot of the cells are free, but whether + + + align:start position:0% +lot of the cells are free, but whether +you're lit or not. And then the rules + + align:start position:0% +you're lit or not. And then the rules + + + align:start position:0% +you're lit or not. And then the rules +are uh so you can think of a light as a + + align:start position:0% +are uh so you can think of a light as a + + + align:start position:0% +are uh so you can think of a light as a +rook in chess. So it can see everything + + align:start position:0% +rook in chess. So it can see everything + + + align:start position:0% +rook in chess. So it can see everything +horizontally in the same row up to + + align:start position:0% +horizontally in the same row up to + + + align:start position:0% +horizontally in the same row up to +obstacles and in the same column up to + + align:start position:0% +obstacles and in the same column up to + + + align:start position:0% +obstacles and in the same column up to +obstacles. So this guy for example + + align:start position:0% +obstacles. So this guy for example + + + align:start position:0% +obstacles. So this guy for example +lights these this portion and this + + align:start position:0% +lights these this portion and this + + + align:start position:0% +lights these this portion and this +portion. This guy lights that portion + + align:start position:0% +portion. This guy lights that portion + + + align:start position:0% +portion. This guy lights that portion +and nothing here and so on. Uh and the + + align:start position:0% +and nothing here and so on. Uh and the + + + align:start position:0% +and nothing here and so on. Uh and the +goal is first of all to light the entire + + align:start position:0% +goal is first of all to light the entire + + + align:start position:0% +goal is first of all to light the entire +board. So that's why it's all green. + + align:start position:0% +board. So that's why it's all green. + + + align:start position:0% +board. So that's why it's all green. +It's all lit um in such in that way. And + + align:start position:0% +It's all lit um in such in that way. And + + + align:start position:0% +It's all lit um in such in that way. And +no two lights should light each other + + align:start position:0% +no two lights should light each other + + + align:start position:0% +no two lights should light each other +because then it's too bright, I guess. I + + align:start position:0% +because then it's too bright, I guess. I + + + align:start position:0% +because then it's too bright, I guess. I +don't know. So uh uh no two rooks can + + align:start position:0% +don't know. So uh uh no two rooks can + + + align:start position:0% +don't know. So uh uh no two rooks can +attack each other would be another + + align:start position:0% +attack each other would be another + + + align:start position:0% +attack each other would be another +perspective. Um and I think those are + + align:start position:0% +perspective. Um and I think those are + + + align:start position:0% +perspective. Um and I think those are +the rules. So you've got to have you've + + align:start position:0% +the rules. So you've got to have you've + + + align:start position:0% +the rules. So you've got to have you've +got to satisfy the number constraint. + + align:start position:0% +got to satisfy the number constraint. + + + align:start position:0% +got to satisfy the number constraint. +You can only place lights in the blank + + align:start position:0% +You can only place lights in the blank + + + align:start position:0% +You can only place lights in the blank +squares. Uh you have to light everything + + align:start position:0% +squares. Uh you have to light everything + + + align:start position:0% +squares. Uh you have to light everything +and they can't see each other. So, this + + align:start position:0% +and they can't see each other. So, this + + + align:start position:0% +and they can't see each other. So, this +is a valid solution. This is puzzle one + + align:start position:0% +is a valid solution. This is puzzle one + + + align:start position:0% +is a valid solution. This is puzzle one +on the Nickel website, and there's a ton + + align:start position:0% +on the Nickel website, and there's a ton + + + align:start position:0% +on the Nickel website, and there's a ton +more if you want to to play. + + align:start position:0% +more if you want to to play. + + + align:start position:0% +more if you want to to play. +But you're saying they can't be in the + + align:start position:0% +But you're saying they can't be in the + + + align:start position:0% +But you're saying they can't be in the +same row or column. + + align:start position:0% +same row or column. + + + align:start position:0% +same row or column. +Uh, I mean, they can be in the same + + align:start position:0% +Uh, I mean, they can be in the same + + + align:start position:0% +Uh, I mean, they can be in the same +column, but they have to be separated by + + align:start position:0% +column, but they have to be separated by + + + align:start position:0% +column, but they have to be separated by +an obstacle. Yeah. So, they can't see + + align:start position:0% +an obstacle. Yeah. So, they can't see + + + align:start position:0% +an obstacle. Yeah. So, they can't see +each other within a sort of sub column + + align:start position:0% +each other within a sort of sub column + + + align:start position:0% +each other within a sort of sub column +or within a sub row + + align:start position:0% +or within a sub row + + + align:start position:0% +or within a sub row +as given by the obstacles. Cool. So, + + align:start position:0% +as given by the obstacles. Cool. So, + + + align:start position:0% +as given by the obstacles. Cool. So, +that's the problem. And now we're going + + align:start position:0% +that's the problem. And now we're going + + + align:start position:0% +that's the problem. And now we're going +to prove that it's empty. Um this is a + + align:start position:0% +to prove that it's empty. Um this is a + + + align:start position:0% +to prove that it's empty. Um this is a +nice proof because it's relatively + + align:start position:0% +nice proof because it's relatively + + + align:start position:0% +nice proof because it's relatively +simple and it illustrates a kind of + + align:start position:0% +simple and it illustrates a kind of + + + align:start position:0% +simple and it illustrates a kind of +circuit SAT style reduction. + + align:start position:0% +circuit SAT style reduction. + + + align:start position:0% +circuit SAT style reduction. +Uh so for starters and most I would say + + align:start position:0% +Uh so for starters and most I would say + + + align:start position:0% +Uh so for starters and most I would say +most SAT proofs a good starting point is + + align:start position:0% +most SAT proofs a good starting point is + + + align:start position:0% +most SAT proofs a good starting point is +a wire gadget. You want to think about + + align:start position:0% +a wire gadget. You want to think about + + + align:start position:0% +a wire gadget. You want to think about +can I make some construction that has + + align:start position:0% +can I make some construction that has + + + align:start position:0% +can I make some construction that has +ideally exactly two solutions one to + + align:start position:0% +ideally exactly two solutions one to + + + align:start position:0% +ideally exactly two solutions one to +represent true one to represent false. + + align:start position:0% +represent true one to represent false. + + + align:start position:0% +represent true one to represent false. +So here are a very variety of ways to do + + align:start position:0% +So here are a very variety of ways to do + + + align:start position:0% +So here are a very variety of ways to do +wires and this is a fairly flexible kind + + align:start position:0% +wires and this is a fairly flexible kind + + + align:start position:0% +wires and this is a fairly flexible kind +of game. The basic one looks like this. + + align:start position:0% +of game. The basic one looks like this. + + + align:start position:0% +of game. The basic one looks like this. +So most of the things are going to be + + align:start position:0% +So most of the things are going to be + + + align:start position:0% +So most of the things are going to be +obstacles to make to tie it down, make + + align:start position:0% +obstacles to make to tie it down, make + + + align:start position:0% +obstacles to make to tie it down, make +it easy to separate gadgets. Uh but here + + align:start position:0% +it easy to separate gadgets. Uh but here + + + align:start position:0% +it easy to separate gadgets. Uh but here +we have two blank squares, a one, two + + align:start position:0% +we have two blank squares, a one, two + + + align:start position:0% +we have two blank squares, a one, two +blank squares, a one, two blank squares. + + align:start position:0% +blank squares, a one, two blank squares. + + + align:start position:0% +blank squares, a one, two blank squares. +That's sort of a simple kind of wire + + align:start position:0% +That's sort of a simple kind of wire + + + align:start position:0% +That's sort of a simple kind of wire +because you know from this one either x + + align:start position:0% +because you know from this one either x + + + align:start position:0% +because you know from this one either x +or x prime is a light. Exactly one of + + align:start position:0% +or x prime is a light. Exactly one of + + + align:start position:0% +or x prime is a light. Exactly one of +them is. So uh that forces alternation. + + align:start position:0% +them is. So uh that forces alternation. + + + align:start position:0% +them is. So uh that forces alternation. +Done. Uh why? uh because if we choose X, + + align:start position:0% +Done. Uh why? uh because if we choose X, + + + align:start position:0% +Done. Uh why? uh because if we choose X, +we can't choose X prime because then + + align:start position:0% +we can't choose X prime because then + + + align:start position:0% +we can't choose X prime because then +they're in the same sub row and all the + + align:start position:0% +they're in the same sub row and all the + + + align:start position:0% +they're in the same sub row and all the +way down the chain. So in general, uh if + + align:start position:0% +way down the chain. So in general, uh if + + + align:start position:0% +way down the chain. So in general, uh if +X is true, the idea is that the X's are + + align:start position:0% +X is true, the idea is that the X's are + + + align:start position:0% +X is true, the idea is that the X's are +the lights. If X is false, then the X + + align:start position:0% +the lights. If X is false, then the X + + + align:start position:0% +the lights. If X is false, then the X +primes are the lights. Okay, now uh + + align:start position:0% +primes are the lights. Okay, now uh + + + align:start position:0% +primes are the lights. Okay, now uh +that's a basic wire, but sort of part of + + align:start position:0% +that's a basic wire, but sort of part of + + + align:start position:0% +that's a basic wire, but sort of part of +the wire is we need a turn gadget. So + + align:start position:0% +the wire is we need a turn gadget. So + + + align:start position:0% +the wire is we need a turn gadget. So +this is a 90° turn. Um just check that + + align:start position:0% +this is a 90° turn. Um just check that + + + align:start position:0% +this is a 90° turn. Um just check that +this is still lit. Uh if these guys + + align:start position:0% +this is still lit. Uh if these guys + + + align:start position:0% +this is still lit. Uh if these guys +could not see each other, I think this + + align:start position:0% +could not see each other, I think this + + + align:start position:0% +could not see each other, I think this +is black. It's also okay. The + + align:start position:0% +is black. It's also okay. The + + + align:start position:0% +is black. It's also okay. The +alternation is forced by the one, but + + align:start position:0% +alternation is forced by the one, but + + + align:start position:0% +alternation is forced by the one, but +some flexibility. + + align:start position:0% +some flexibility. + + + align:start position:0% +some flexibility. +Uh, and let's see. Uh, the other fun + + align:start position:0% +Uh, and let's see. Uh, the other fun + + + align:start position:0% +Uh, and let's see. Uh, the other fun +thing you can do is spread out the x and + + align:start position:0% +thing you can do is spread out the x and + + + align:start position:0% +thing you can do is spread out the x and +x prime. If you put a bunch of zeros + + align:start position:0% +x prime. If you put a bunch of zeros + + + align:start position:0% +x prime. If you put a bunch of zeros +here to force that there's no lights + + align:start position:0% +here to force that there's no lights + + + align:start position:0% +here to force that there's no lights +here, uh, because this has to be lit. + + align:start position:0% +here, uh, because this has to be lit. + + + align:start position:0% +here, uh, because this has to be lit. +Again, one of these has to be active and + + align:start position:0% +Again, one of these has to be active and + + + align:start position:0% +Again, one of these has to be active and +the ones force an alternation. So, this + + align:start position:0% +the ones force an alternation. So, this + + + align:start position:0% +the ones force an alternation. So, this +is helpful uh because if our wires just + + align:start position:0% +is helpful uh because if our wires just + + + align:start position:0% +is helpful uh because if our wires just +look like this, and we'll we this will + + align:start position:0% +look like this, and we'll we this will + + + align:start position:0% +look like this, and we'll we this will +come up again today. uh then you're + + align:start position:0% +come up again today. uh then you're + + + align:start position:0% +come up again today. uh then you're +forced to be congruent to zero mod 3. + + align:start position:0% +forced to be congruent to zero mod 3. + + + align:start position:0% +forced to be congruent to zero mod 3. +You have first of your width has to be a + + align:start position:0% +You have first of your width has to be a + + + align:start position:0% +You have first of your width has to be a +multiple of three. Uh and this can be an + + align:start position:0% +multiple of three. Uh and this can be an + + + align:start position:0% +multiple of three. Uh and this can be an +issue if you have a bunch of gadgets + + align:start position:0% +issue if you have a bunch of gadgets + + + align:start position:0% +issue if you have a bunch of gadgets +each of different sizes. Maybe one is + + align:start position:0% +each of different sizes. Maybe one is + + + align:start position:0% +each of different sizes. Maybe one is +5x5, another's 3x3 and other fun prime + + align:start position:0% +5x5, another's 3x3 and other fun prime + + + align:start position:0% +5x5, another's 3x3 and other fun prime +numbers, then you might have trouble + + align:start position:0% +numbers, then you might have trouble + + + align:start position:0% +numbers, then you might have trouble +actually getting gadgets to meet edge + + align:start position:0% +actually getting gadgets to meet edge + + + align:start position:0% +actually getting gadgets to meet edge +on. Uh maybe there's a gap of one or two + + align:start position:0% +on. Uh maybe there's a gap of one or two + + + align:start position:0% +on. Uh maybe there's a gap of one or two +or something between the gadgets. Uh but + + align:start position:0% +or something between the gadgets. Uh but + + + align:start position:0% +or something between the gadgets. Uh but +once you if you have a setup where you + + align:start position:0% +once you if you have a setup where you + + + align:start position:0% +once you if you have a setup where you +can make wires you can adjust the wire + + align:start position:0% +can make wires you can adjust the wire + + + align:start position:0% +can make wires you can adjust the wire +lengths to be any integer that's good + + align:start position:0% +lengths to be any integer that's good + + + align:start position:0% +lengths to be any integer that's good +because then you can go do this most of + + align:start position:0% +because then you can go do this most of + + + align:start position:0% +because then you can go do this most of +the time but then when you're getting + + align:start position:0% +the time but then when you're getting + + + align:start position:0% +the time but then when you're getting +close to the gate uh if you're off by + + align:start position:0% +close to the gate uh if you're off by + + + align:start position:0% +close to the gate uh if you're off by +one or two or three you just uh make it + + align:start position:0% +one or two or three you just uh make it + + + align:start position:0% +one or two or three you just uh make it +a little bit longer and you're all set. + + align:start position:0% +a little bit longer and you're all set. + + + align:start position:0% +a little bit longer and you're all set. +The unfilled one can also just have a + + align:start position:0% +The unfilled one can also just have a + + + align:start position:0% +The unfilled one can also just have a +crossover gadget. Then + + align:start position:0% +crossover gadget. Then + + + align:start position:0% +crossover gadget. Then +uh sorry + + align:start position:0% +uh sorry + + + align:start position:0% +uh sorry +since you have nothing it's very natural + + align:start position:0% +since you have nothing it's very natural + + + align:start position:0% +since you have nothing it's very natural +to have a crossover gadget by putting + + align:start position:0% +to have a crossover gadget by putting + + + align:start position:0% +to have a crossover gadget by putting +two of them orthogonal. + + align:start position:0% +two of them orthogonal. + + + align:start position:0% +two of them orthogonal. +Oh yeah, you can make a crossover gadget + + align:start position:0% +Oh yeah, you can make a crossover gadget + + + align:start position:0% +Oh yeah, you can make a crossover gadget +easy in this setup. I think that is a + + align:start position:0% +easy in this setup. I think that is a + + + align:start position:0% +easy in this setup. I think that is a +future slide. + + align:start position:0% +future slide. + + + align:start position:0% +future slide. +Um let's so we'll do crossover in a bit. + + align:start position:0% +Um let's so we'll do crossover in a bit. + + + align:start position:0% +Um let's so we'll do crossover in a bit. +Let's start with uh yeah you can very + + align:start position:0% +Let's start with uh yeah you can very + + + align:start position:0% +Let's start with uh yeah you can very +easily do a crossover. Uh we won't need + + align:start position:0% +easily do a crossover. Uh we won't need + + + align:start position:0% +easily do a crossover. Uh we won't need +a crossover here. That's what I mean. + + align:start position:0% +a crossover here. That's what I mean. + + + align:start position:0% +a crossover here. That's what I mean. +Uh so we definitely need splitting + + align:start position:0% +Uh so we definitely need splitting + + + align:start position:0% +Uh so we definitely need splitting +though in general whenever you have + + align:start position:0% +though in general whenever you have + + + align:start position:0% +though in general whenever you have +wires you've got to be able to make + + align:start position:0% +wires you've got to be able to make + + + align:start position:0% +wires you've got to be able to make +copies because if your variable only + + align:start position:0% +copies because if your variable only + + + align:start position:0% +copies because if your variable only +appears in two places uh threes is easy + + align:start position:0% +appears in two places uh threes is easy + + + align:start position:0% +appears in two places uh threes is easy +or circuit set is probably easy. Uh so + + align:start position:0% +or circuit set is probably easy. Uh so + + + align:start position:0% +or circuit set is probably easy. Uh so +uh here is a splitter. Uh this is the + + align:start position:0% +uh here is a splitter. Uh this is the + + + align:start position:0% +uh here is a splitter. Uh this is the +the main mechanism. Uh I guess these + + align:start position:0% +the main mechanism. Uh I guess these + + + align:start position:0% +the main mechanism. Uh I guess these +ones and this two. So these ones force + + align:start position:0% +ones and this two. So these ones force + + + align:start position:0% +ones and this two. So these ones force +an alternation uh between here and here. + + align:start position:0% +an alternation uh between here and here. + + + align:start position:0% +an alternation uh between here and here. +These have to be opposites of each + + align:start position:0% +These have to be opposites of each + + + align:start position:0% +These have to be opposites of each +other. and then the two. So if both of + + align:start position:0% +other. and then the two. So if both of + + + align:start position:0% +other. and then the two. So if both of +the x's are present, if this is absent, + + align:start position:0% +the x's are present, if this is absent, + + + align:start position:0% +the x's are present, if this is absent, +then these two have to be present by the + + align:start position:0% +then these two have to be present by the + + + align:start position:0% +then these two have to be present by the +ones. And so by this two, that's all + + align:start position:0% +ones. And so by this two, that's all + + + align:start position:0% +ones. And so by this two, that's all +there is. And therefore, this is absent. + + align:start position:0% +there is. And therefore, this is absent. + + + align:start position:0% +there is. And therefore, this is absent. +So these guys have to be the same. These + + align:start position:0% +So these guys have to be the same. These + + + align:start position:0% +So these guys have to be the same. These +guys have to be opposite. Uh and + + align:start position:0% +guys have to be opposite. Uh and + + + align:start position:0% +guys have to be opposite. Uh and +conversely, if this is present by these + + align:start position:0% +conversely, if this is present by these + + + align:start position:0% +conversely, if this is present by these +ones, these have to be absent. And by + + align:start position:0% +ones, these have to be absent. And by + + + align:start position:0% +ones, these have to be absent. And by +this two, this has to be present. So + + align:start position:0% +this two, this has to be present. So + + + align:start position:0% +this two, this has to be present. So +this is this is almost sort of a well, + + align:start position:0% +this is this is almost sort of a well, + + + align:start position:0% +this is this is almost sort of a well, +you could also put some ones here, I + + align:start position:0% +you could also put some ones here, I + + + align:start position:0% +you could also put some ones here, I +guess, uh if you felt like it. Anyway, + + align:start position:0% +guess, uh if you felt like it. Anyway, + + + align:start position:0% +guess, uh if you felt like it. Anyway, +if you think about the parity here, what + + align:start position:0% +if you think about the parity here, what + + + align:start position:0% +if you think about the parity here, what +we we have for an when we're + + align:start position:0% +we we have for an when we're + + + align:start position:0% +we we have for an when we're +representing a signal coming into a + + align:start position:0% +representing a signal coming into a + + + align:start position:0% +representing a signal coming into a +gadget, there's X on the left and X + + align:start position:0% +gadget, there's X on the left and X + + + align:start position:0% +gadget, there's X on the left and X +prime on the right. Uh so that means + + align:start position:0% +prime on the right. Uh so that means + + + align:start position:0% +prime on the right. Uh so that means +coming out here, there's now X prime on + + align:start position:0% +coming out here, there's now X prime on + + + align:start position:0% +coming out here, there's now X prime on +the left and X on the right. So this is + + align:start position:0% +the left and X on the right. So this is + + + align:start position:0% +the left and X on the right. So this is +actually a negated copy of X. Um and up + + align:start position:0% +actually a negated copy of X. Um and up + + + align:start position:0% +actually a negated copy of X. Um and up +here with some turns, uh we have a + + align:start position:0% +here with some turns, uh we have a + + + align:start position:0% +here with some turns, uh we have a +regular copy of X and a regular copy of + + align:start position:0% +regular copy of X and a regular copy of + + + align:start position:0% +regular copy of X and a regular copy of +X. This is actually a fairly common + + align:start position:0% +X. This is actually a fairly common + + + align:start position:0% +X. This is actually a fairly common +thing that happens when you try to + + align:start position:0% +thing that happens when you try to + + + align:start position:0% +thing that happens when you try to +split. Maybe you also get a negated copy + + align:start position:0% +split. Maybe you also get a negated copy + + + align:start position:0% +split. Maybe you also get a negated copy +or instead you get a negated copy. Uh + + align:start position:0% +or instead you get a negated copy. Uh + + + align:start position:0% +or instead you get a negated copy. Uh +this is actually great because it kills + + align:start position:0% +this is actually great because it kills + + + align:start position:0% +this is actually great because it kills +two birds with one stone. You can use + + align:start position:0% +two birds with one stone. You can use + + + align:start position:0% +two birds with one stone. You can use +this as a splitter. It kind of makes + + align:start position:0% +this as a splitter. It kind of makes + + + align:start position:0% +this as a splitter. It kind of makes +three copies of your signal. Uh but you + + align:start position:0% +three copies of your signal. Uh but you + + + align:start position:0% +three copies of your signal. Uh but you +can also use it just as a negation + + align:start position:0% +can also use it just as a negation + + + align:start position:0% +can also use it just as a negation +gadget as a not gate. I think I have a + + align:start position:0% +gadget as a not gate. I think I have a + + + align:start position:0% +gadget as a not gate. I think I have a +slide of those done explicitly. + + align:start position:0% +slide of those done explicitly. + + + align:start position:0% +slide of those done explicitly. +Uh yeah. So uh here we're effectively + + align:start position:0% +Uh yeah. So uh here we're effectively + + + align:start position:0% +Uh yeah. So uh here we're effectively +using a terminator gadget. We're saying, + + align:start position:0% +using a terminator gadget. We're saying, + + + align:start position:0% +using a terminator gadget. We're saying, +well, we could throw away this negated + + align:start position:0% +well, we could throw away this negated + + + align:start position:0% +well, we could throw away this negated +copy because we already have two + + align:start position:0% +copy because we already have two + + + align:start position:0% +copy because we already have two +positive copies and that's enough for a + + align:start position:0% +positive copies and that's enough for a + + + align:start position:0% +positive copies and that's enough for a +splitter. So, if we just end the the + + align:start position:0% +splitter. So, if we just end the the + + + align:start position:0% +splitter. So, if we just end the the +this wire here, great, we've got a + + align:start position:0% +this wire here, great, we've got a + + + align:start position:0% +this wire here, great, we've got a +split. Um, or if we throw away the two + + align:start position:0% +split. Um, or if we throw away the two + + + align:start position:0% +split. Um, or if we throw away the two +copies of X and we just want the negated + + align:start position:0% +copies of X and we just want the negated + + + align:start position:0% +copies of X and we just want the negated +copy of X, then ends up looking like + + align:start position:0% +copy of X, then ends up looking like + + + align:start position:0% +copy of X, then ends up looking like +this. So, we get uh a split gadget and a + + align:start position:0% +this. So, we get uh a split gadget and a + + + align:start position:0% +this. So, we get uh a split gadget and a +notgate essentially for free out of + + align:start position:0% +notgate essentially for free out of + + + align:start position:0% +notgate essentially for free out of +this. You could just present this gadget + + align:start position:0% +this. You could just present this gadget + + + align:start position:0% +this. You could just present this gadget +and say, "Oh, I also have terminators." + + align:start position:0% +and say, "Oh, I also have terminators." + + + align:start position:0% +and say, "Oh, I also have terminators." +And then you know that you get these uh + + align:start position:0% +And then you know that you get these uh + + + align:start position:0% +And then you know that you get these uh +but for fun he drew them and I'll show + + align:start position:0% +but for fun he drew them and I'll show + + + align:start position:0% +but for fun he drew them and I'll show +you them. I won't show you them in + + align:start position:0% +you them. I won't show you them in + + + align:start position:0% +you them. I won't show you them in +future proofs but + + align:start position:0% +future proofs but + + + align:start position:0% +future proofs but +uh cool. So let's see what do we have. + + align:start position:0% +uh cool. So let's see what do we have. + + + align:start position:0% +uh cool. So let's see what do we have. +We've got a wire. + + align:start position:0% +We've got a wire. + + + align:start position:0% +We've got a wire. +We've got a split. We've got a knot. + + align:start position:0% +We've got a split. We've got a knot. + + + align:start position:0% +We've got a split. We've got a knot. +We've got a terminator. Uh we need some + + align:start position:0% +We've got a terminator. Uh we need some + + + align:start position:0% +We've got a terminator. Uh we need some +kind of clause or some kind of logic + + align:start position:0% +kind of clause or some kind of logic + + + align:start position:0% +kind of clause or some kind of logic +gate. Uh and then possibly we also need + + align:start position:0% +gate. Uh and then possibly we also need + + + align:start position:0% +gate. Uh and then possibly we also need +a crossover. We have turns. + + align:start position:0% +a crossover. We have turns. + + + align:start position:0% +a crossover. We have turns. +Okay. So, + + align:start position:0% +Okay. So, + + + align:start position:0% +Okay. So, +uh, next up is a, uh, gate. It's sort of + + align:start position:0% +uh, next up is a, uh, gate. It's sort of + + + align:start position:0% +uh, next up is a, uh, gate. It's sort of +a a mega gate. I'm guessing, uh, McFale + + align:start position:0% +a a mega gate. I'm guessing, uh, McFale + + + align:start position:0% +a a mega gate. I'm guessing, uh, McFale +tried various little configurations and + + align:start position:0% +tried various little configurations and + + + align:start position:0% +tried various little configurations and +then found one that did interesting + + align:start position:0% +then found one that did interesting + + + align:start position:0% +then found one that did interesting +things. It actually does, uh, two + + align:start position:0% +things. It actually does, uh, two + + + align:start position:0% +things. It actually does, uh, two +interesting things at once. So, we have + + align:start position:0% +interesting things at once. So, we have + + + align:start position:0% +interesting things at once. So, we have +X coming in on the left and Y coming in + + align:start position:0% +X coming in on the left and Y coming in + + + align:start position:0% +X coming in on the left and Y coming in +on the right. So, both of them have this + + align:start position:0% +on the right. So, both of them have this + + + align:start position:0% +on the right. So, both of them have this +X- prime and Y prime, the negated + + align:start position:0% +X- prime and Y prime, the negated + + + align:start position:0% +X- prime and Y prime, the negated +copies. And then we've got some fun + + align:start position:0% +copies. And then we've got some fun + + + align:start position:0% +copies. And then we've got some fun +stuff in here. So, uh, let's start with + + align:start position:0% +stuff in here. So, uh, let's start with + + + align:start position:0% +stuff in here. So, uh, let's start with +maybe the bottom, which is supposed to + + align:start position:0% +maybe the bottom, which is supposed to + + + align:start position:0% +maybe the bottom, which is supposed to +be an ore of X and Y. So, um, let's say + + align:start position:0% +be an ore of X and Y. So, um, let's say + + + align:start position:0% +be an ore of X and Y. So, um, let's say +that they are both false, for example. + + align:start position:0% +that they are both false, for example. + + + align:start position:0% +that they are both false, for example. +And general, we're going to have to + + align:start position:0% +And general, we're going to have to + + + align:start position:0% +And general, we're going to have to +check all the cases, but I won't do all + + align:start position:0% +check all the cases, but I won't do all + + + align:start position:0% +check all the cases, but I won't do all +of them. So, let's say this is absent. + + align:start position:0% +of them. So, let's say this is absent. + + + align:start position:0% +of them. So, let's say this is absent. +This is absent, meaning the other it's + + align:start position:0% +This is absent, meaning the other it's + + + align:start position:0% +This is absent, meaning the other it's +lit from the other end. + + align:start position:0% +lit from the other end. + + + align:start position:0% +lit from the other end. +If it's false, it means X prime is + + align:start position:0% +If it's false, it means X prime is + + + align:start position:0% +If it's false, it means X prime is +present. + + align:start position:0% +present. + + + align:start position:0% +present. +Oh, right. Sorry. Right. If they're both + + align:start position:0% +Oh, right. Sorry. Right. If they're both + + + align:start position:0% +Oh, right. Sorry. Right. If they're both +false, good. uh then both of these are + + align:start position:0% +false, good. uh then both of these are + + + align:start position:0% +false, good. uh then both of these are +present and therefore uh we're gonna get + + align:start position:0% +present and therefore uh we're gonna get + + + align:start position:0% +present and therefore uh we're gonna get +hopefully that this one is absent + + align:start position:0% +hopefully that this one is absent + + + align:start position:0% +hopefully that this one is absent +because the ore of false and false is + + align:start position:0% +because the ore of false and false is + + + align:start position:0% +because the ore of false and false is +false. Uh so the claim would be that a + + align:start position:0% +false. Uh so the claim would be that a + + + align:start position:0% +false. Uh so the claim would be that a +prime and b prime must be activated. + + align:start position:0% +prime and b prime must be activated. + + + align:start position:0% +prime and b prime must be activated. +If they weren't then you couldn't light + + align:start position:0% +If they weren't then you couldn't light + + + align:start position:0% +If they weren't then you couldn't light +both A and B. + + align:start position:0% +both A and B. + + + align:start position:0% +both A and B. +Uh right these are at best ored + + align:start position:0% +Uh right these are at best ored + + + align:start position:0% +Uh right these are at best ored +together. At most one of these is + + align:start position:0% +together. At most one of these is + + + align:start position:0% +together. At most one of these is +present. These regions both need to be + + align:start position:0% +present. These regions both need to be + + + align:start position:0% +present. These regions both need to be +lit. Uh, so we're going to need uh at + + align:start position:0% +lit. Uh, so we're going to need uh at + + + align:start position:0% +lit. Uh, so we're going to need uh at +least one of them to be on, but once one + + align:start position:0% +least one of them to be on, but once one + + + align:start position:0% +least one of them to be on, but once one +of them is on, we know that Z is absent. + + align:start position:0% +of them is on, we know that Z is absent. + + + align:start position:0% +of them is on, we know that Z is absent. +And then the other one must be on. Try + + align:start position:0% +And then the other one must be on. Try + + + align:start position:0% +And then the other one must be on. Try +this two. Good. + + align:start position:0% +this two. Good. + + + align:start position:0% +this two. Good. +Okay. And then we should up here get + + align:start position:0% +Okay. And then we should up here get + + + align:start position:0% +Okay. And then we should up here get +Xnor + + align:start position:0% +Xnor + + + align:start position:0% +Xnor +uh because so when these were both false + + align:start position:0% +uh because so when these were both false + + + align:start position:0% +uh because so when these were both false +and present, these were present. Uh + + align:start position:0% +and present, these were present. Uh + + + align:start position:0% +and present, these were present. Uh +these are absent and therefore this is + + align:start position:0% +these are absent and therefore this is + + + align:start position:0% +these are absent and therefore this is +present. and the xor of 0 and 0 is zero. + + align:start position:0% +present. and the xor of 0 and 0 is zero. + + + align:start position:0% +present. and the xor of 0 and 0 is zero. +The x nor is one. So that's good. So in + + align:start position:0% +The x nor is one. So that's good. So in + + + align:start position:0% +The x nor is one. So that's good. So in +general, you check all the cases and + + align:start position:0% +general, you check all the cases and + + + align:start position:0% +general, you check all the cases and +confirm this is the case. Again, by + + align:start position:0% +confirm this is the case. Again, by + + + align:start position:0% +confirm this is the case. Again, by +putting terminators on here, we can get + + align:start position:0% +putting terminators on here, we can get + + + align:start position:0% +putting terminators on here, we can get +either x or y or x nor x x nor y sounds + + align:start position:0% +either x or y or x nor x x nor y sounds + + + align:start position:0% +either x or y or x nor x x nor y sounds +funny. Um that's great. Uh we actually + + align:start position:0% +funny. Um that's great. Uh we actually + + + align:start position:0% +funny. Um that's great. Uh we actually +uh this is the one that we really care + + align:start position:0% +uh this is the one that we really care + + + align:start position:0% +uh this is the one that we really care +about. Uh the or gate. Well, so + + align:start position:0% +about. Uh the or gate. Well, so + + + align:start position:0% +about. Uh the or gate. Well, so +different answers to this, but uh you + + align:start position:0% +different answers to this, but uh you + + + align:start position:0% +different answers to this, but uh you +should know and we'll talk more about + + align:start position:0% +should know and we'll talk more about + + + align:start position:0% +should know and we'll talk more about +this later. NAND and or let's say + + align:start position:0% +this later. NAND and or let's say + + + align:start position:0% +this later. NAND and or let's say +the NANDgate is universal + + align:start position:0% + + + + align:start position:0% + +and a NOR gate by itself is universal. + + align:start position:0% + + + + align:start position:0% + +These are just good things you should + + align:start position:0% +These are just good things you should + + + align:start position:0% +These are just good things you should +know. Uh they go back at least 50 years. + + align:start position:0% +know. Uh they go back at least 50 years. + + + align:start position:0% +know. Uh they go back at least 50 years. +And uh + + align:start position:0% +And uh + + + align:start position:0% +And uh +what does universal mean? + + align:start position:0% +what does universal mean? + + + align:start position:0% +what does universal mean? +Uh so universal means that from that + + align:start position:0% +Uh so universal means that from that + + + align:start position:0% +Uh so universal means that from that +those from if you're just given a bunch + + align:start position:0% +those from if you're just given a bunch + + + align:start position:0% +those from if you're just given a bunch +of nans then you can construct any + + align:start position:0% +of nans then you can construct any + + + align:start position:0% +of nans then you can construct any +logical gate you want. Uh I will talk + + align:start position:0% +logical gate you want. Uh I will talk + + + align:start position:0% +logical gate you want. Uh I will talk +about that more in a moment. So this ore + + align:start position:0% +about that more in a moment. So this ore + + + align:start position:0% +about that more in a moment. So this ore +is particularly interesting because we + + align:start position:0% +is particularly interesting because we + + + align:start position:0% +is particularly interesting because we +already have not. And so from from or + + align:start position:0% +already have not. And so from from or + + + align:start position:0% +already have not. And so from from or +and not we can make nor it's just the + + align:start position:0% +and not we can make nor it's just the + + + align:start position:0% +and not we can make nor it's just the +knot of the ore. And so from that we + + align:start position:0% +knot of the ore. And so from that we + + + align:start position:0% +knot of the ore. And so from that we +should be able to make anything + + align:start position:0% +should be able to make anything + + + align:start position:0% +should be able to make anything +which is great except uh for one thing + + align:start position:0% +which is great except uh for one thing + + + align:start position:0% +which is great except uh for one thing +which is the crossover gadget. So in the + + align:start position:0% +which is the crossover gadget. So in the + + + align:start position:0% +which is the crossover gadget. So in the +case of lightup uh crossover gadget is + + align:start position:0% +case of lightup uh crossover gadget is + + + align:start position:0% +case of lightup uh crossover gadget is +easy to construct but uh because we have + + align:start position:0% +easy to construct but uh because we have + + + align:start position:0% +easy to construct but uh because we have +exor anyway we can use this fun fact + + align:start position:0% +exor anyway we can use this fun fact + + + align:start position:0% +exor anyway we can use this fun fact +that if you this is a symbol for exor. + + align:start position:0% +that if you this is a symbol for exor. + + + align:start position:0% +that if you this is a symbol for exor. +If you have exor gadgets, you can make + + align:start position:0% +If you have exor gadgets, you can make + + + align:start position:0% +If you have exor gadgets, you can make +uh a crossover gadget for free. So this + + align:start position:0% +uh a crossover gadget for free. So this + + + align:start position:0% +uh a crossover gadget for free. So this +communicates x to x y to y. Again, + + align:start position:0% +communicates x to x y to y. Again, + + + align:start position:0% +communicates x to x y to y. Again, +there's four cases. I won't check all of + + align:start position:0% +there's four cases. I won't check all of + + + align:start position:0% +there's four cases. I won't check all of +them. Uh but that's cool because we have + + align:start position:0% +them. Uh but that's cool because we have + + + align:start position:0% +them. Uh but that's cool because we have +x nor. We can negate it and get xor. And + + align:start position:0% +x nor. We can negate it and get xor. And + + + align:start position:0% +x nor. We can negate it and get xor. And +then we can take three of them, plug + + align:start position:0% +then we can take three of them, plug + + + align:start position:0% +then we can take three of them, plug +them together, and we get a rather + + align:start position:0% +them together, and we get a rather + + + align:start position:0% +them together, and we get a rather +complicated crossover gadget. If I + + align:start position:0% +complicated crossover gadget. If I + + + align:start position:0% +complicated crossover gadget. If I +expanded it out, there is a simpler one, + + align:start position:0% +expanded it out, there is a simpler one, + + + align:start position:0% +expanded it out, there is a simpler one, +but we don't care about simplicity here. + + align:start position:0% +but we don't care about simplicity here. + + + align:start position:0% +but we don't care about simplicity here. +These are just constants. uh and we just + + align:start position:0% +These are just constants. uh and we just + + + align:start position:0% +These are just constants. uh and we just +care about polomial. So uh that's light + + align:start position:0% +care about polomial. So uh that's light + + + align:start position:0% +care about polomial. So uh that's light +up is MP MP hard. Yeah. + + align:start position:0% +up is MP MP hard. Yeah. + + + align:start position:0% +up is MP MP hard. Yeah. +Do we need crossover gadgets in general + + align:start position:0% +Do we need crossover gadgets in general + + + align:start position:0% +Do we need crossover gadgets in general +for circuit set? Is planner circuit set + + align:start position:0% +for circuit set? Is planner circuit set + + + align:start position:0% +for circuit set? Is planner circuit set +hard? + + align:start position:0% +hard? + + + align:start position:0% +hard? +Please wait. + + align:start position:0% +Please wait. + + + align:start position:0% +Please wait. +Yeah. Uh this is a something well yeah I + + align:start position:0% +Yeah. Uh this is a something well yeah I + + + align:start position:0% +Yeah. Uh this is a something well yeah I +want to talk about that after the next + + align:start position:0% +want to talk about that after the next + + + align:start position:0% +want to talk about that after the next +example. + + align:start position:0% +example. + + + align:start position:0% +example. +Okay. uh which we'll get to an answer to + + align:start position:0% +Okay. uh which we'll get to an answer to + + + align:start position:0% +Okay. uh which we'll get to an answer to +that question which as far as I know + + align:start position:0% +that question which as far as I know + + + align:start position:0% +that question which as far as I know +haven't hasn't been explicitly raised + + align:start position:0% +haven't hasn't been explicitly raised + + + align:start position:0% +haven't hasn't been explicitly raised +before but uh it's pretty the answer is + + align:start position:0% +before but uh it's pretty the answer is + + + align:start position:0% +before but uh it's pretty the answer is +basically you don't need crossover + + align:start position:0% +basically you don't need crossover + + + align:start position:0% +basically you don't need crossover +gadgets and for all the cases I can + + align:start position:0% +gadgets and for all the cases I can + + + align:start position:0% +gadgets and for all the cases I can +think of so uh that was lightup is np + + align:start position:0% +think of so uh that was lightup is np + + + align:start position:0% +think of so uh that was lightup is np +hard it's also innp because certificate + + align:start position:0% +hard it's also innp because certificate + + + align:start position:0% +hard it's also innp because certificate +is just where do you put the lights + + align:start position:0% +is just where do you put the lights + + + align:start position:0% +is just where do you put the lights +there's only polinomial number of places + + align:start position:0% +there's only polinomial number of places + + + align:start position:0% +there's only polinomial number of places +to put them and checking it is easy cool + + align:start position:0% +to put them and checking it is easy cool + + + align:start position:0% +to put them and checking it is easy cool +so nplete + + align:start position:0% +so nplete + + + align:start position:0% +so nplete +oh here's uh for on an overall + + align:start position:0% +oh here's uh for on an overall + + + align:start position:0% +oh here's uh for on an overall +construction which uh McFale worked out. + + align:start position:0% +construction which uh McFale worked out. + + + align:start position:0% +construction which uh McFale worked out. +So putting all the pieces together and + + align:start position:0% +So putting all the pieces together and + + + align:start position:0% +So putting all the pieces together and +possibly using I think here there's + + align:start position:0% +possibly using I think here there's + + + align:start position:0% +possibly using I think here there's +maybe no crossovers. + + align:start position:0% +maybe no crossovers. + + + align:start position:0% +maybe no crossovers. +Uh but so so in general with circuit set + + align:start position:0% +Uh but so so in general with circuit set + + + align:start position:0% +Uh but so so in general with circuit set +you can construct sort of any boolean + + align:start position:0% +you can construct sort of any boolean + + + align:start position:0% +you can construct sort of any boolean +formula you want once you have a + + align:start position:0% +formula you want once you have a + + + align:start position:0% +formula you want once you have a +universal uh set of gates. Um but yeah + + align:start position:0% +universal uh set of gates. Um but yeah + + + align:start position:0% +universal uh set of gates. Um but yeah +you can work through details here once + + align:start position:0% +you can work through details here once + + + align:start position:0% +you can work through details here once +you have it's easy to convert between + + align:start position:0% +you have it's easy to convert between + + + align:start position:0% +you have it's easy to convert between +and and or uh just by negating the + + align:start position:0% +and and or uh just by negating the + + + align:start position:0% +and and or uh just by negating the +inputs by deorggan right so you've got + + align:start position:0% +inputs by deorggan right so you've got + + + align:start position:0% +inputs by deorggan right so you've got +uh not x or y is not x and not y or vice + + align:start position:0% +uh not x or y is not x and not y or vice + + + align:start position:0% +uh not x or y is not x and not y or vice +versa. So as long as you've got not and + + align:start position:0% +versa. So as long as you've got not and + + + align:start position:0% +versa. So as long as you've got not and +or you can construct and and vice versa + + align:start position:0% +or you can construct and and vice versa + + + align:start position:0% +or you can construct and and vice versa +by negating things appropriately. + + align:start position:0% +by negating things appropriately. + + + align:start position:0% +by negating things appropriately. +So that's what he's doing here for + + align:start position:0% +So that's what he's doing here for + + + align:start position:0% +So that's what he's doing here for +getting some ores and and so on. + + align:start position:0% +getting some ores and and so on. + + + align:start position:0% +getting some ores and and so on. +And because there's two copies of X uh + + align:start position:0% +And because there's two copies of X uh + + + align:start position:0% +And because there's two copies of X uh +while X is sort of getting split here. I + + align:start position:0% +while X is sort of getting split here. I + + + align:start position:0% +while X is sort of getting split here. I +guess you didn't have to split X. You + + align:start position:0% +guess you didn't have to split X. You + + + align:start position:0% +guess you didn't have to split X. You +could just connect directly. But + + align:start position:0% +could just connect directly. But + + + align:start position:0% +could just connect directly. But +this is a pretty nice clean + + align:start position:0% +this is a pretty nice clean + + + align:start position:0% +this is a pretty nice clean +construction. You could actually make + + align:start position:0% +construction. You could actually make + + + align:start position:0% +construction. You could actually make +decently sized puzzles with it. + + align:start position:0% +decently sized puzzles with it. + + + align:start position:0% +decently sized puzzles with it. +So you end up with the wire carrying the + + align:start position:0% +So you end up with the wire carrying the + + + align:start position:0% +So you end up with the wire carrying the +formula just by doing all these + + align:start position:0% +formula just by doing all these + + + align:start position:0% +formula just by doing all these +combinations, right? + + align:start position:0% +combinations, right? + + + align:start position:0% +combinations, right? +And then what you do? + + align:start position:0% +And then what you do? + + + align:start position:0% +And then what you do? +Ah, good point. Thank you. There's there + + align:start position:0% +Ah, good point. Thank you. There's there + + + align:start position:0% +Ah, good point. Thank you. There's there +was one more point to to this picture + + align:start position:0% +was one more point to to this picture + + + align:start position:0% +was one more point to to this picture +which is this zero. This should be an or + + align:start position:0% +which is this zero. This should be an or + + + align:start position:0% +which is this zero. This should be an or +of x false and this ore of this and of + + align:start position:0% +of x false and this ore of this and of + + + align:start position:0% +of x false and this ore of this and of +blah blah blah which is this thing. Uh + + align:start position:0% +blah blah blah which is this thing. Uh + + + align:start position:0% +blah blah blah which is this thing. Uh +so + + align:start position:0% +so + + + align:start position:0% +so +so if that wire is carrying true then + + align:start position:0% +so if that wire is carrying true then + + + align:start position:0% +so if that wire is carrying true then +you don't need to put a light next to + + align:start position:0% +you don't need to put a light next to + + + align:start position:0% +you don't need to put a light next to +the zero otherwise you would have to but + + align:start position:0% +the zero otherwise you would have to but + + + align:start position:0% +the zero otherwise you would have to but +then that means the puzzle can't be + + align:start position:0% +then that means the puzzle can't be + + + align:start position:0% +then that means the puzzle can't be +solved + + align:start position:0% +solved + + + align:start position:0% +solved +right so for this puzzle to be solvable + + align:start position:0% +right so for this puzzle to be solvable + + + align:start position:0% +right so for this puzzle to be solvable +uh we better not put a light here which + + align:start position:0% +uh we better not put a light here which + + + align:start position:0% +uh we better not put a light here which +means it has to be here which + + align:start position:0% +means it has to be here which + + + align:start position:0% +means it has to be here which +corresponds to this formula being true I + + align:start position:0% +corresponds to this formula being true I + + + align:start position:0% +corresponds to this formula being true I +think if I got the par right so or + + align:start position:0% +think if I got the par right so or + + + align:start position:0% +think if I got the par right so or +either way you could put a one there and + + align:start position:0% +either way you could put a one there and + + + align:start position:0% +either way you could put a one there and +force there to be a light + + align:start position:0% +force there to be a light + + + align:start position:0% +force there to be a light +uh so this makes the puzzle feasible if + + align:start position:0% +uh so this makes the puzzle feasible if + + + align:start position:0% +uh so this makes the puzzle feasible if +and only if this formula is feasible + + align:start position:0% +and only if this formula is feasible + + + align:start position:0% +and only if this formula is feasible +because the wires are unconstrained + + align:start position:0% +because the wires are unconstrained + + + align:start position:0% +because the wires are unconstrained +except by setting this thing equal to + + align:start position:0% +except by setting this thing equal to + + + align:start position:0% +except by setting this thing equal to +one. + + align:start position:0% +one. + + + align:start position:0% +one. +Yeah. So, this is a special kind of + + align:start position:0% +Yeah. So, this is a special kind of + + + align:start position:0% +Yeah. So, this is a special kind of +terminator, you might say, uh, a true + + align:start position:0% +terminator, you might say, uh, a true + + + align:start position:0% +terminator, you might say, uh, a true +terminator if you want to force the + + align:start position:0% +terminator if you want to force the + + + align:start position:0% +terminator if you want to force the +thing to be true in the end. That's + + align:start position:0% +thing to be true in the end. That's + + + align:start position:0% +thing to be true in the end. That's +usually pretty easy to do. Terminators + + align:start position:0% +usually pretty easy to do. Terminators + + + align:start position:0% +usually pretty easy to do. Terminators +are usually one of the simplest gadgets + + align:start position:0% +are usually one of the simplest gadgets + + + align:start position:0% +are usually one of the simplest gadgets +to worry about. But yeah, you do need + + align:start position:0% +to worry about. But yeah, you do need + + + align:start position:0% +to worry about. But yeah, you do need +it. For circuit set, you need let's add + + align:start position:0% +it. For circuit set, you need let's add + + + align:start position:0% +it. For circuit set, you need let's add +that. + + align:start position:0% + + + + align:start position:0% + +Circuit set. you need to uh let's say a + + align:start position:0% +Circuit set. you need to uh let's say a + + + align:start position:0% +Circuit set. you need to uh let's say a +true terminator. + + align:start position:0% +true terminator. + + + align:start position:0% +true terminator. +There are other ways you could do it, + + align:start position:0% +There are other ways you could do it, + + + align:start position:0% +There are other ways you could do it, +but + + align:start position:0% + + + + align:start position:0% + +cool. Other questions about Aotti? + + align:start position:0% +cool. Other questions about Aotti? + + + align:start position:0% +cool. Other questions about Aotti? +All right, so uh next topic is + + align:start position:0% +All right, so uh next topic is + + + align:start position:0% +All right, so uh next topic is +Mindeeper. This is from our poster. We + + align:start position:0% +Mindeeper. This is from our poster. We + + + align:start position:0% +Mindeeper. This is from our poster. We +did Super Mario Brothers and briefly did + + align:start position:0% +did Super Mario Brothers and briefly did + + + align:start position:0% +did Super Mario Brothers and briefly did +Rush Hour, so Mind Sweeper is the last + + align:start position:0% +Rush Hour, so Mind Sweeper is the last + + + align:start position:0% +Rush Hour, so Mind Sweeper is the last +one on the poster. Um let's prove it + + align:start position:0% +one on the poster. Um let's prove it + + + align:start position:0% +one on the poster. Um let's prove it +hard. + + align:start position:0% +hard. + + + align:start position:0% +hard. +Uh we're actually going to cover two + + align:start position:0% +Uh we're actually going to cover two + + + align:start position:0% +Uh we're actually going to cover two +proofs about mind sweeper uh because + + align:start position:0% +proofs about mind sweeper uh because + + + align:start position:0% +proofs about mind sweeper uh because +there are sort of two natural problems + + align:start position:0% +there are sort of two natural problems + + + align:start position:0% +there are sort of two natural problems +you might ask about it. The first + + align:start position:0% +you might ask about it. The first + + + align:start position:0% +you might ask about it. The first +problem is uh consistency. So this is I + + align:start position:0% +problem is uh consistency. So this is I + + + align:start position:0% +problem is uh consistency. So this is I +give you uh a setup. I'm going to give + + align:start position:0% +give you uh a setup. I'm going to give + + + align:start position:0% +give you uh a setup. I'm going to give +you a partially solved board that you're + + align:start position:0% +you a partially solved board that you're + + + align:start position:0% +you a partially solved board that you're +not given the x levels. Uh so just a + + align:start position:0% +not given the x levels. Uh so just a + + + align:start position:0% +not given the x levels. Uh so just a +regular instance of mind sweeper. Uh + + align:start position:0% +regular instance of mind sweeper. Uh + + + align:start position:0% +regular instance of mind sweeper. Uh +maybe you're told where some of the + + align:start position:0% +maybe you're told where some of the + + + align:start position:0% +maybe you're told where some of the +bombs are. Uh it won't actually matter + + align:start position:0% +bombs are. Uh it won't actually matter + + + align:start position:0% +bombs are. Uh it won't actually matter +because all the bombs that I'll draw + + align:start position:0% +because all the bombs that I'll draw + + + align:start position:0% +because all the bombs that I'll draw +here are derable. you know from this I + + align:start position:0% +here are derable. you know from this I + + + align:start position:0% +here are derable. you know from this I +should mention the rules of mind sweeper + + align:start position:0% +should mention the rules of mind sweeper + + + align:start position:0% +should mention the rules of mind sweeper +just in case you haven't played anyone + + align:start position:0% +just in case you haven't played anyone + + + align:start position:0% +just in case you haven't played anyone +not played mind sweeper + + align:start position:0% +not played mind sweeper + + + align:start position:0% +not played mind sweeper +not willing to admit it so the numbers + + align:start position:0% +not willing to admit it so the numbers + + + align:start position:0% +not willing to admit it so the numbers +here representing among all your vertex + + align:start position:0% +here representing among all your vertex + + + align:start position:0% +here representing among all your vertex +neighbors all eight neighbors how many + + align:start position:0% +neighbors all eight neighbors how many + + + align:start position:0% +neighbors all eight neighbors how many +of them are bombs uh you don't want to + + align:start position:0% +of them are bombs uh you don't want to + + + align:start position:0% +of them are bombs uh you don't want to +click on the bombs because then you die + + align:start position:0% +click on the bombs because then you die + + + align:start position:0% +click on the bombs because then you die +so your goal is to from this partial + + align:start position:0% +so your goal is to from this partial + + + align:start position:0% +so your goal is to from this partial +information these blank squares + + align:start position:0% +information these blank squares + + + align:start position:0% +information these blank squares +represent zeros from this partial + + align:start position:0% +represent zeros from this partial + + + align:start position:0% +represent zeros from this partial +information you want to figure out where + + align:start position:0% +information you want to figure out where + + + align:start position:0% +information you want to figure out where +the bombs must be + + align:start position:0% +the bombs must be + + + align:start position:0% +the bombs must be +and + + align:start position:0% +and + + + align:start position:0% +and +here's a very familiar looking wire. Uh + + align:start position:0% +here's a very familiar looking wire. Uh + + + align:start position:0% +here's a very familiar looking wire. Uh +here, um we're we can't just have + + align:start position:0% +here, um we're we can't just have + + + align:start position:0% +here, um we're we can't just have +obstacles that are wild cards. So, we + + align:start position:0% +obstacles that are wild cards. So, we + + + align:start position:0% +obstacles that are wild cards. So, we +have to put it numbers if we don't want + + align:start position:0% +have to put it numbers if we don't want + + + align:start position:0% +have to put it numbers if we don't want +there to be bombs there. That makes the + + align:start position:0% +there to be bombs there. That makes the + + + align:start position:0% +there to be bombs there. That makes the +gadgets quite a bit trickier to work + + align:start position:0% +gadgets quite a bit trickier to work + + + align:start position:0% +gadgets quite a bit trickier to work +with. But, uh this looks pretty similar. + + align:start position:0% +with. But, uh this looks pretty similar. + + + align:start position:0% +with. But, uh this looks pretty similar. +We've got these ones which force an + + align:start position:0% +We've got these ones which force an + + + align:start position:0% +We've got these ones which force an +alternation. Exactly one of these two is + + align:start position:0% +alternation. Exactly one of these two is + + + align:start position:0% +alternation. Exactly one of these two is +a bomb. So, if x is present, x prime is + + align:start position:0% +a bomb. So, if x is present, x prime is + + + align:start position:0% +a bomb. So, if x is present, x prime is +absent. Vice versa. Um and then this one + + align:start position:0% +absent. Vice versa. Um and then this one + + + align:start position:0% +absent. Vice versa. Um and then this one +forces I guess actually this one forces + + align:start position:0% +forces I guess actually this one forces + + + align:start position:0% +forces I guess actually this one forces +these to be opposite. + + align:start position:0% +these to be opposite. + + + align:start position:0% +these to be opposite. +So uh that forces the alternation down + + align:start position:0% +So uh that forces the alternation down + + + align:start position:0% +So uh that forces the alternation down +the line. So again there are exactly two + + align:start position:0% +the line. So again there are exactly two + + + align:start position:0% +the line. So again there are exactly two +solutions to this wire gadget uh for + + align:start position:0% +solutions to this wire gadget uh for + + + align:start position:0% +solutions to this wire gadget uh for +where the bombs could be. And so the + + align:start position:0% +where the bombs could be. And so the + + + align:start position:0% +where the bombs could be. And so the +mind sweeper consistency problem is I + + align:start position:0% +mind sweeper consistency problem is I + + + align:start position:0% +mind sweeper consistency problem is I +give you some picture involving these + + align:start position:0% +give you some picture involving these + + + align:start position:0% +give you some picture involving these +things. Uh and I want to know is there a + + align:start position:0% +things. Uh and I want to know is there a + + + align:start position:0% +things. Uh and I want to know is there a +solution to uh is there a placement of + + align:start position:0% +solution to uh is there a placement of + + + align:start position:0% +solution to uh is there a placement of +the bombs that satisfies all of these + + align:start position:0% +the bombs that satisfies all of these + + + align:start position:0% +the bombs that satisfies all of these +constraints. Okay. Now uh you might ask + + align:start position:0% +constraints. Okay. Now uh you might ask + + + align:start position:0% +constraints. Okay. Now uh you might ask +why is that the problem we care about? + + align:start position:0% +why is that the problem we care about? + + + align:start position:0% +why is that the problem we care about? +Um, and one reason if you're playing + + align:start position:0% +Um, and one reason if you're playing + + + align:start position:0% +Um, and one reason if you're playing +Mind Sweeper, you'd like to know, for + + align:start position:0% +Mind Sweeper, you'd like to know, for + + + align:start position:0% +Mind Sweeper, you'd like to know, for +example, could there be a bomb at this + + align:start position:0% +example, could there be a bomb at this + + + align:start position:0% +example, could there be a bomb at this +position? Uh, so could there be a bomb + + align:start position:0% +position? Uh, so could there be a bomb + + + align:start position:0% +position? Uh, so could there be a bomb +at this position? I could solve that + + align:start position:0% +at this position? I could solve that + + + align:start position:0% +at this position? I could solve that +problem potentially if I could solve + + align:start position:0% +problem potentially if I could solve + + + align:start position:0% +problem potentially if I could solve +mind sweeper consistency by saying, uh, + + align:start position:0% +mind sweeper consistency by saying, uh, + + + align:start position:0% +mind sweeper consistency by saying, uh, +let's put a bomb there as part of the + + align:start position:0% +let's put a bomb there as part of the + + + align:start position:0% +let's put a bomb there as part of the +partial information. Is that consistent + + align:start position:0% +partial information. Is that consistent + + + align:start position:0% +partial information. Is that consistent +with everything else? So add a bomb to + + align:start position:0% +with everything else? So add a bomb to + + + align:start position:0% +with everything else? So add a bomb to +the partial information. Is that a + + align:start position:0% +the partial information. Is that a + + + align:start position:0% +the partial information. Is that a +consistent configuration? + + align:start position:0% +consistent configuration? + + + align:start position:0% +consistent configuration? +Uh, so if I could solve mind sweeper + + align:start position:0% +Uh, so if I could solve mind sweeper + + + align:start position:0% +Uh, so if I could solve mind sweeper +consistency, I could play a mind sweeper + + align:start position:0% +consistency, I could play a mind sweeper + + + align:start position:0% +consistency, I could play a mind sweeper +very well by just testing which are + + align:start position:0% +very well by just testing which are + + + align:start position:0% +very well by just testing which are +bombable positions. If they're not + + align:start position:0% +bombable positions. If they're not + + + align:start position:0% +bombable positions. If they're not +possible to be a bomb there, I should + + align:start position:0% +possible to be a bomb there, I should + + + align:start position:0% +possible to be a bomb there, I should +click there and get more information and + + align:start position:0% +click there and get more information and + + + align:start position:0% +click there and get more information and +cook until done. Now maybe you could + + align:start position:0% +cook until done. Now maybe you could + + + align:start position:0% +cook until done. Now maybe you could +solve mind sweeper in a different way + + align:start position:0% +solve mind sweeper in a different way + + + align:start position:0% +solve mind sweeper in a different way +than using consistency. But one way to + + align:start position:0% +than using consistency. But one way to + + + align:start position:0% +than using consistency. But one way to +solve it would be consistency. Question. + + align:start position:0% +solve it would be consistency. Question. + + + align:start position:0% +solve it would be consistency. Question. +By consistency, you don't mean unique + + align:start position:0% +By consistency, you don't mean unique + + + align:start position:0% +By consistency, you don't mean unique +solution. + + align:start position:0% +solution. + + + align:start position:0% +solution. +I do not mean unique solution, right? + + align:start position:0% +I do not mean unique solution, right? + + + align:start position:0% +I do not mean unique solution, right? +Yeah. So when you actually want to solve + + align:start position:0% +Yeah. So when you actually want to solve + + + align:start position:0% +Yeah. So when you actually want to solve +the game, you'd like there to be unique + + align:start position:0% +the game, you'd like there to be unique + + + align:start position:0% +the game, you'd like there to be unique +solution. That's a problem we will get + + align:start position:0% +solution. That's a problem we will get + + + align:start position:0% +solution. That's a problem we will get +to in a moment. + + align:start position:0% +to in a moment. + + + align:start position:0% +to in a moment. +So, a blank board, unfilled information + + align:start position:0% +So, a blank board, unfilled information + + + align:start position:0% +So, a blank board, unfilled information +is consistent. + + align:start position:0% +is consistent. + + + align:start position:0% +is consistent. +Yes. Completely blank board is + + align:start position:0% +Yes. Completely blank board is + + + align:start position:0% +Yes. Completely blank board is +consistent. And wouldn't it be + + align:start position:0% +consistent. And wouldn't it be + + + align:start position:0% +consistent. And wouldn't it be +interesting if as you're playing you + + align:start position:0% +interesting if as you're playing you + + + align:start position:0% +interesting if as you're playing you +imagine you've got you've gathered some + + align:start position:0% +imagine you've got you've gathered some + + + align:start position:0% +imagine you've got you've gathered some +information, you add a bomb, you want to + + align:start position:0% +information, you add a bomb, you want to + + + align:start position:0% +information, you add a bomb, you want to +say, is this consistent? If it says yes, + + align:start position:0% +say, is this consistent? If it says yes, + + + align:start position:0% +say, is this consistent? If it says yes, +like you have a blank board, like could + + align:start position:0% +like you have a blank board, like could + + + align:start position:0% +like you have a blank board, like could +there be a bomb here? Of course there + + align:start position:0% +there be a bomb here? Of course there + + + align:start position:0% +there be a bomb here? Of course there +could be. Uh then that's not a safe + + align:start position:0% +could be. Uh then that's not a safe + + + align:start position:0% +could be. Uh then that's not a safe +move. So, this will help you. If you + + align:start position:0% +move. So, this will help you. If you + + + align:start position:0% +move. So, this will help you. If you +could solve this, uh you could identify + + align:start position:0% +could solve this, uh you could identify + + + align:start position:0% +could solve this, uh you could identify +safe moves. Turns out you can't solve + + align:start position:0% +safe moves. Turns out you can't solve + + + align:start position:0% +safe moves. Turns out you can't solve +it. So, uh it doesn't directly help you. + + align:start position:0% +it. So, uh it doesn't directly help you. + + + align:start position:0% +it. So, uh it doesn't directly help you. +Yeah. + + align:start position:0% +Yeah. + + + align:start position:0% +Yeah. +So, um there doesn't always exist a safe + + align:start position:0% +So, um there doesn't always exist a safe + + + align:start position:0% +So, um there doesn't always exist a safe +move. + + align:start position:0% +move. + + + align:start position:0% +move. +There doesn't always exist a safe move, + + align:start position:0% +There doesn't always exist a safe move, + + + align:start position:0% +There doesn't always exist a safe move, +right? + + align:start position:0% +right? + + + align:start position:0% +right? +What good is it kind of + + align:start position:0% +What good is it kind of + + + align:start position:0% +What good is it kind of +um + + align:start position:0% +um + + + align:start position:0% +um +to know whether you see what I mean? + + align:start position:0% +to know whether you see what I mean? + + + align:start position:0% +to know whether you see what I mean? +Like + + align:start position:0% +Like + + + align:start position:0% +Like +I would say consistency is the wrong + + align:start position:0% +I would say consistency is the wrong + + + align:start position:0% +I would say consistency is the wrong +problem to solve for mind sweeper. Uh we + + align:start position:0% +problem to solve for mind sweeper. Uh we + + + align:start position:0% +problem to solve for mind sweeper. Uh we +will get but it was the first problem + + align:start position:0% +will get but it was the first problem + + + align:start position:0% +will get but it was the first problem +solved. It the gadgets are relatively + + align:start position:0% +solved. It the gadgets are relatively + + + align:start position:0% +solved. It the gadgets are relatively +easy which is going to be fairly + + align:start position:0% +easy which is going to be fairly + + + align:start position:0% +easy which is going to be fairly +complicated. uh and then we'll get to + + align:start position:0% +complicated. uh and then we'll get to + + + align:start position:0% +complicated. uh and then we'll get to +the right problem for if you wanted to + + align:start position:0% +the right problem for if you wanted to + + + align:start position:0% +the right problem for if you wanted to +solve the puzzle. It's just at this + + align:start position:0% +solve the puzzle. It's just at this + + + align:start position:0% +solve the puzzle. It's just at this +point it's an interesting question. You + + align:start position:0% +point it's an interesting question. You + + + align:start position:0% +point it's an interesting question. You +just want to know is it consistent? Did + + align:start position:0% +just want to know is it consistent? Did + + + align:start position:0% +just want to know is it consistent? Did +the computer cheat would be one other + + align:start position:0% +the computer cheat would be one other + + + align:start position:0% +the computer cheat would be one other +perspective or you could imagine some + + align:start position:0% +perspective or you could imagine some + + + align:start position:0% +perspective or you could imagine some +adversarial mind sweeper where you only + + align:start position:0% +adversarial mind sweeper where you only + + + align:start position:0% +adversarial mind sweeper where you only +decide the bombs as the person is + + align:start position:0% +decide the bombs as the person is + + + align:start position:0% +decide the bombs as the person is +playing. + + align:start position:0% +playing. + + + align:start position:0% +playing. +So this would so here just even telling + + align:start position:0% +So this would so here just even telling + + + align:start position:0% +So this would so here just even telling +whether your opponent is cheating is + + align:start position:0% +whether your opponent is cheating is + + + align:start position:0% +whether your opponent is cheating is +hard. Okay. So that's that's another + + align:start position:0% +hard. Okay. So that's that's another + + + align:start position:0% +hard. Okay. So that's that's another +perspective. So okay let's finish this + + align:start position:0% +perspective. So okay let's finish this + + + align:start position:0% +perspective. So okay let's finish this +proof. Uh we have a terminator uh which + + align:start position:0% +proof. Uh we have a terminator uh which + + + align:start position:0% +proof. Uh we have a terminator uh which +is actually a little bit tricky here. + + align:start position:0% +is actually a little bit tricky here. + + + align:start position:0% +is actually a little bit tricky here. +You can't just end with ones because + + align:start position:0% +You can't just end with ones because + + + align:start position:0% +You can't just end with ones because +that would force this guy to be a bomb. + + align:start position:0% +that would force this guy to be a bomb. + + + align:start position:0% +that would force this guy to be a bomb. +So you end with these threes which force + + align:start position:0% +So you end with these threes which force + + + align:start position:0% +So you end with these threes which force +uh these guys are already bombs because + + align:start position:0% +uh these guys are already bombs because + + + align:start position:0% +uh these guys are already bombs because +of this picture. Uh and then exactly one + + align:start position:0% +of this picture. Uh and then exactly one + + + align:start position:0% +of this picture. Uh and then exactly one +of those will still have to be a bomb. + + align:start position:0% +of those will still have to be a bomb. + + + align:start position:0% +of those will still have to be a bomb. +Okay. And then we have a splitter. Uh + + align:start position:0% +Okay. And then we have a splitter. Uh + + + align:start position:0% +Okay. And then we have a splitter. Uh +this is similar picture to Aari. Uh we + + align:start position:0% +this is similar picture to Aari. Uh we + + + align:start position:0% +this is similar picture to Aari. Uh we +have this two which forces exactly two + + align:start position:0% +have this two which forces exactly two + + + align:start position:0% +have this two which forces exactly two +of these to be present and these ones + + align:start position:0% +of these to be present and these ones + + + align:start position:0% +of these to be present and these ones +force alternation. So that makes uh now + + align:start position:0% +force alternation. So that makes uh now + + + align:start position:0% +force alternation. So that makes uh now +I'm orienting things I'm orienting these + + align:start position:0% +I'm orienting things I'm orienting these + + + align:start position:0% +I'm orienting things I'm orienting these +arrows for the splitter and defining + + align:start position:0% +arrows for the splitter and defining + + + align:start position:0% +arrows for the splitter and defining +true to be when the the pointy the + + align:start position:0% +true to be when the the pointy the + + + align:start position:0% +true to be when the the pointy the +pointy end of the arrow is present. Um + + align:start position:0% +pointy end of the arrow is present. Um + + + align:start position:0% +pointy end of the arrow is present. Um +so that means this is actually a negated + + align:start position:0% +so that means this is actually a negated + + + align:start position:0% +so that means this is actually a negated +copy and these are unnegated copies. Uh + + align:start position:0% +copy and these are unnegated copies. Uh + + + align:start position:0% +copy and these are unnegated copies. Uh +but that's only from the orientation. + + align:start position:0% +but that's only from the orientation. + + + align:start position:0% +but that's only from the orientation. +This gadget is actually symmetric + + align:start position:0% +This gadget is actually symmetric + + + align:start position:0% +This gadget is actually symmetric +four-fold but uh but if you put these + + align:start position:0% +four-fold but uh but if you put these + + + align:start position:0% +four-fold but uh but if you put these +arrows in which you would do if you're + + align:start position:0% +arrows in which you would do if you're + + + align:start position:0% +arrows in which you would do if you're +actually following a circuit it's a + + align:start position:0% +actually following a circuit it's a + + + align:start position:0% +actually following a circuit it's a +directed our circuits are directed a + + align:start position:0% +directed our circuits are directed a + + + align:start position:0% +directed our circuits are directed a +cyclic graphs remember so uh this is + + align:start position:0% +cyclic graphs remember so uh this is + + + align:start position:0% +cyclic graphs remember so uh this is +negation which is good because it gives + + align:start position:0% +negation which is good because it gives + + + align:start position:0% +negation which is good because it gives +us a knot also gives us a split you can + + align:start position:0% +us a knot also gives us a split you can + + + align:start position:0% +us a knot also gives us a split you can +also uh end these two things and get a + + align:start position:0% +also uh end these two things and get a + + + align:start position:0% +also uh end these two things and get a +turn so great three gadgets in one + + align:start position:0% +turn so great three gadgets in one + + + align:start position:0% +turn so great three gadgets in one +uh so uh we already have not this is + + align:start position:0% +uh so uh we already have not this is + + + align:start position:0% +uh so uh we already have not this is +another way to do not and it's + + align:start position:0% +another way to do not and it's + + + align:start position:0% +another way to do not and it's +interesting here because uh with Aari we + + align:start position:0% +interesting here because uh with Aari we + + + align:start position:0% +interesting here because uh with Aari we +could stretch wires to any length uh any + + align:start position:0% +could stretch wires to any length uh any + + + align:start position:0% +could stretch wires to any length uh any +integer length that is long sufficiently + + align:start position:0% +integer length that is long sufficiently + + + align:start position:0% +integer length that is long sufficiently +long. Uh here we're forced in this u + + align:start position:0% +long. Uh here we're forced in this u + + + align:start position:0% +long. Uh here we're forced in this u +modulo 3 picture normally. But when we + + align:start position:0% +modulo 3 picture normally. But when we + + + align:start position:0% +modulo 3 picture normally. But when we +do something like a negation here we we + + align:start position:0% +do something like a negation here we we + + + align:start position:0% +do something like a negation here we we +get kind of messed up. We're no longer + + align:start position:0% +get kind of messed up. We're no longer + + + align:start position:0% +get kind of messed up. We're no longer +in the same position modulo 3. + + align:start position:0% +in the same position modulo 3. + + + align:start position:0% +in the same position modulo 3. +Uh we should be uh off by one I believe. + + align:start position:0% +Uh we should be uh off by one I believe. + + + align:start position:0% +Uh we should be uh off by one I believe. +So the idea is if you do two negations + + align:start position:0% +So the idea is if you do two negations + + + align:start position:0% +So the idea is if you do two negations +in a row uh then you can end up shifting + + align:start position:0% +in a row uh then you can end up shifting + + + align:start position:0% +in a row uh then you can end up shifting +by exactly two um and still have the + + align:start position:0% +by exactly two um and still have the + + + align:start position:0% +by exactly two um and still have the +same signal. Uh so you can see here we + + align:start position:0% +same signal. Uh so you can see here we + + + align:start position:0% +same signal. Uh so you can see here we +have xxar + + align:start position:0% +have xxar + + + align:start position:0% +have xxar +but uh down here we have it shifted uh + + align:start position:0% +but uh down here we have it shifted uh + + + align:start position:0% +but uh down here we have it shifted uh +two positions over uh yeah or I guess + + align:start position:0% +two positions over uh yeah or I guess + + + align:start position:0% +two positions over uh yeah or I guess +it's more impressive over here. So xarx + + align:start position:0% +it's more impressive over here. So xarx + + + align:start position:0% +it's more impressive over here. So xarx +um and normally this would repeat in + + align:start position:0% +um and normally this would repeat in + + + align:start position:0% +um and normally this would repeat in +this kind of pattern. + + align:start position:0% +this kind of pattern. + + + align:start position:0% +this kind of pattern. +Ah, so it actually shifted by one + + align:start position:0% +Ah, so it actually shifted by one + + + align:start position:0% +Ah, so it actually shifted by one +position. Good. That's that's actually + + align:start position:0% +position. Good. That's that's actually + + + align:start position:0% +position. Good. That's that's actually +what I want. So see the pattern here, + + align:start position:0% +what I want. So see the pattern here, + + + align:start position:0% +what I want. So see the pattern here, +here, here, here, and shift by one. + + align:start position:0% +here, here, here, and shift by one. + + + align:start position:0% +here, here, here, and shift by one. +Yeah. Or to the other direction. + + align:start position:0% +Yeah. Or to the other direction. + + + align:start position:0% +Yeah. Or to the other direction. +Okay. So that's good. That that lets me + + align:start position:0% +Okay. So that's good. That that lets me + + + align:start position:0% +Okay. So that's good. That that lets me +adjust my wire lengths. Uh these are + + align:start position:0% +adjust my wire lengths. Uh these are + + + align:start position:0% +adjust my wire lengths. Uh these are +also often called shift gadgets. Uh they + + align:start position:0% +also often called shift gadgets. Uh they + + + align:start position:0% +also often called shift gadgets. Uh they +just sort of let you shift by one. And + + align:start position:0% +just sort of let you shift by one. And + + + align:start position:0% +just sort of let you shift by one. And +whenever you have gadgets that force + + align:start position:0% +whenever you have gadgets that force + + + align:start position:0% +whenever you have gadgets that force +certain modulo constraints, just having + + align:start position:0% +certain modulo constraints, just having + + + align:start position:0% +certain modulo constraints, just having +the ability to add one is great because + + align:start position:0% +the ability to add one is great because + + + align:start position:0% +the ability to add one is great because +then you can break all such constraints. + + align:start position:0% +then you can break all such constraints. + + + align:start position:0% +then you can break all such constraints. +You no longer have to live in a mod 3 + + align:start position:0% +You no longer have to live in a mod 3 + + + align:start position:0% +You no longer have to live in a mod 3 +grid or whatever if you don't want to. + + align:start position:0% +grid or whatever if you don't want to. + + + align:start position:0% +grid or whatever if you don't want to. +So this is important in general. Uh + + align:start position:0% +So this is important in general. Uh + + + align:start position:0% +So this is important in general. Uh +maybe I'll add it to the list here. Um, + + align:start position:0% +maybe I'll add it to the list here. Um, + + + align:start position:0% +maybe I'll add it to the list here. Um, +when you're dealing with wires, uh, you + + align:start position:0% +when you're dealing with wires, uh, you + + + align:start position:0% +when you're dealing with wires, uh, you +may need some kind of shift gadget that + + align:start position:0% +may need some kind of shift gadget that + + + align:start position:0% +may need some kind of shift gadget that +lets you, uh, fix par issues, or in this + + align:start position:0% +lets you, uh, fix par issues, or in this + + + align:start position:0% +lets you, uh, fix par issues, or in this +case, a mod 3 par. + + align:start position:0% +case, a mod 3 par. + + + align:start position:0% +case, a mod 3 par. +Okay. Uh, here's a more complicated + + align:start position:0% +Okay. Uh, here's a more complicated + + + align:start position:0% +Okay. Uh, here's a more complicated +gadget, which I will not go through. It + + align:start position:0% +gadget, which I will not go through. It + + + align:start position:0% +gadget, which I will not go through. It +looks scary. It's not actually a ton + + align:start position:0% +looks scary. It's not actually a ton + + + align:start position:0% +looks scary. It's not actually a ton +going on. It's a lot of gadgets we've + + align:start position:0% +going on. It's a lot of gadgets we've + + + align:start position:0% +going on. It's a lot of gadgets we've +already seen. Um, it uses a slight I've + + align:start position:0% +already seen. Um, it uses a slight I've + + + align:start position:0% +already seen. Um, it uses a slight I've +mentioned a turn gadget. This is another + + align:start position:0% +mentioned a turn gadget. This is another + + + align:start position:0% +mentioned a turn gadget. This is another +way to do a turn. Uh there's a few + + align:start position:0% +way to do a turn. Uh there's a few + + + align:start position:0% +way to do a turn. Uh there's a few +redundant gadgets in this paper because + + align:start position:0% +redundant gadgets in this paper because + + + align:start position:0% +redundant gadgets in this paper because +it's fun to make gadgets. So why not + + align:start position:0% +it's fun to make gadgets. So why not + + + align:start position:0% +it's fun to make gadgets. So why not +have more? Um and uh so there's for + + align:start position:0% +have more? Um and uh so there's for + + + align:start position:0% +have more? Um and uh so there's for +example just a turn gadget here. There's + + align:start position:0% +example just a turn gadget here. There's + + + align:start position:0% +example just a turn gadget here. There's +a splitter here. Another turn gadget. + + align:start position:0% +a splitter here. Another turn gadget. + + + align:start position:0% +a splitter here. Another turn gadget. +This is uh reflectionally symmetric + + align:start position:0% +This is uh reflectionally symmetric + + + align:start position:0% +This is uh reflectionally symmetric +around the x-axis. Uh there's basically + + align:start position:0% +around the x-axis. Uh there's basically + + + align:start position:0% +around the x-axis. Uh there's basically +just a turn here. So x is just getting + + align:start position:0% +just a turn here. So x is just getting + + + align:start position:0% +just a turn here. So x is just getting +copied or and negated into here. Uh z is + + align:start position:0% +copied or and negated into here. Uh z is + + + align:start position:0% +copied or and negated into here. Uh z is +getting copied and negated into here. Um + + align:start position:0% +getting copied and negated into here. Um + + + align:start position:0% +getting copied and negated into here. Um +this is the output value which is + + align:start position:0% +this is the output value which is + + + align:start position:0% +this is the output value which is +getting copied around into here. And + + align:start position:0% +getting copied around into here. And + + + align:start position:0% +getting copied around into here. And +then a little bit of magic happens here + + align:start position:0% +then a little bit of magic happens here + + + align:start position:0% +then a little bit of magic happens here +and here to get these to interact in the + + align:start position:0% +and here to get these to interact in the + + + align:start position:0% +and here to get these to interact in the +right way. And it's essentially just + + align:start position:0% +right way. And it's essentially just + + + align:start position:0% +right way. And it's essentially just +checking uh cases to see that this + + align:start position:0% +checking uh cases to see that this + + + align:start position:0% +checking uh cases to see that this +computes an of these two inputs. + + align:start position:0% +computes an of these two inputs. + + + align:start position:0% +computes an of these two inputs. +Okay. Uh but you know a little bit + + align:start position:0% +Okay. Uh but you know a little bit + + + align:start position:0% +Okay. Uh but you know a little bit +complicated. + + align:start position:0% +complicated. + + + align:start position:0% +complicated. +Is coming up with these gadgets harder + + align:start position:0% +Is coming up with these gadgets harder + + + align:start position:0% +Is coming up with these gadgets harder +than checking them? Uh, + + align:start position:0% +than checking them? Uh, + + + align:start position:0% +than checking them? Uh, +good question. It's unclear. Often when + + align:start position:0% +good question. It's unclear. Often when + + + align:start position:0% +good question. It's unclear. Often when +you're designing things, you have a lot + + align:start position:0% +you're designing things, you have a lot + + + align:start position:0% +you're designing things, you have a lot +more control and it could potentially be + + align:start position:0% +more control and it could potentially be + + + align:start position:0% +more control and it could potentially be +easier to design hard problems than to + + align:start position:0% +easier to design hard problems than to + + + align:start position:0% +easier to design hard problems than to +check them. Uh, because we know it's + + align:start position:0% +check them. Uh, because we know it's + + + align:start position:0% +check them. Uh, because we know it's +MPcomplete to check this. So, in in a + + align:start position:0% +MPcomplete to check this. So, in in a + + + align:start position:0% +MPcomplete to check this. So, in in a +certain sense, uh, yeah, I mean, of + + align:start position:0% +certain sense, uh, yeah, I mean, of + + + align:start position:0% +certain sense, uh, yeah, I mean, of +course, in this case, there's only four + + align:start position:0% +course, in this case, there's only four + + + align:start position:0% +course, in this case, there's only four +cases, so it's not really that hard. Uh + + align:start position:0% +cases, so it's not really that hard. Uh + + + align:start position:0% +cases, so it's not really that hard. Uh +but yeah, when you're designing things, + + align:start position:0% +but yeah, when you're designing things, + + + align:start position:0% +but yeah, when you're designing things, +you you have in mind a certain + + align:start position:0% +you you have in mind a certain + + + align:start position:0% +you you have in mind a certain +connectivity structure and then it's a + + align:start position:0% +connectivity structure and then it's a + + + align:start position:0% +connectivity structure and then it's a +matter of getting things to resolve in + + align:start position:0% +matter of getting things to resolve in + + + align:start position:0% +matter of getting things to resolve in +the grid and not have cross things + + align:start position:0% +the grid and not have cross things + + + align:start position:0% +the grid and not have cross things +overlapping and so on, which is a + + align:start position:0% +overlapping and so on, which is a + + + align:start position:0% +overlapping and so on, which is a +different kind of constraint. It's + + align:start position:0% +different kind of constraint. It's + + + align:start position:0% +different kind of constraint. It's +usually a I might say it's a more fun + + align:start position:0% +usually a I might say it's a more fun + + + align:start position:0% +usually a I might say it's a more fun +one. I would call designing these + + align:start position:0% +one. I would call designing these + + + align:start position:0% +one. I would call designing these +puzzles metapuzzles and to me that's + + align:start position:0% +puzzles metapuzzles and to me that's + + + align:start position:0% +puzzles metapuzzles and to me that's +more fun, but of course I'm a + + align:start position:0% +more fun, but of course I'm a + + + align:start position:0% +more fun, but of course I'm a +theoretical computer scientist, so + + align:start position:0% +theoretical computer scientist, so + + + align:start position:0% +theoretical computer scientist, so +that's uh that's why we're here. Um + + align:start position:0% +that's uh that's why we're here. Um + + + align:start position:0% +that's uh that's why we're here. Um +anyway, yeah, fun abstract question. + + align:start position:0% +anyway, yeah, fun abstract question. + + + align:start position:0% +anyway, yeah, fun abstract question. +Uh so here's a fun thing. I hadn't seen + + align:start position:0% +Uh so here's a fun thing. I hadn't seen + + + align:start position:0% +Uh so here's a fun thing. I hadn't seen +this paper before uh by uh Goldlogger in + + align:start position:0% +this paper before uh by uh Goldlogger in + + + align:start position:0% +this paper before uh by uh Goldlogger in +1977. Uh they were worried about + + align:start position:0% +1977. Uh they were worried about + + + align:start position:0% +1977. Uh they were worried about +Pmpleteness, which we haven't talked + + align:start position:0% +Pmpleteness, which we haven't talked + + + align:start position:0% +Pmpleteness, which we haven't talked +about yet, but uh in particular, they + + align:start position:0% +about yet, but uh in particular, they + + + align:start position:0% +about yet, but uh in particular, they +give these two pictures. This one we've + + align:start position:0% +give these two pictures. This one we've + + + align:start position:0% +give these two pictures. This one we've +seen uh from if you have an exor gadget, + + align:start position:0% +seen uh from if you have an exor gadget, + + + align:start position:0% +seen uh from if you have an exor gadget, +you can construct a crossover. Now, we + + align:start position:0% +you can construct a crossover. Now, we + + + align:start position:0% +you can construct a crossover. Now, we +don't have an exor gadget in this case, + + align:start position:0% +don't have an exor gadget in this case, + + + align:start position:0% +don't have an exor gadget in this case, +but we have an AND gadget or a NAND + + align:start position:0% +but we have an AND gadget or a NAND + + + align:start position:0% +but we have an AND gadget or a NAND +gadget. This is a funny way of writing + + align:start position:0% +gadget. This is a funny way of writing + + + align:start position:0% +gadget. This is a funny way of writing +NAND, not of an and. And if you have + + align:start position:0% +NAND, not of an and. And if you have + + + align:start position:0% +NAND, not of an and. And if you have +NAND gadgets, you can construct an exor. + + align:start position:0% +NAND gadgets, you can construct an exor. + + + align:start position:0% +NAND gadgets, you can construct an exor. +So if you plug this picture into each of + + align:start position:0% +So if you plug this picture into each of + + + align:start position:0% +So if you plug this picture into each of +these three pictures, you get a kind of + + align:start position:0% +these three pictures, you get a kind of + + + align:start position:0% +these three pictures, you get a kind of +ugly thing, but it's planer and it + + align:start position:0% +ugly thing, but it's planer and it + + + align:start position:0% +ugly thing, but it's planer and it +implements a crossover, which means if + + align:start position:0% +implements a crossover, which means if + + + align:start position:0% +implements a crossover, which means if +you have NAND, you get planerity for + + align:start position:0% +you have NAND, you get planerity for + + + align:start position:0% +you have NAND, you get planerity for +free. Okay. So, I'm going to call this + + align:start position:0% +free. Okay. So, I'm going to call this + + + align:start position:0% +free. Okay. So, I'm going to call this +uh + + align:start position:0% + + + + align:start position:0% + +planer circuit set. + + align:start position:0% + + + + align:start position:0% + +Slight catch is that this I think is + + align:start position:0% +Slight catch is that this I think is + + + align:start position:0% +Slight catch is that this I think is +also a madeup term. I haven't seen it in + + align:start position:0% +also a madeup term. I haven't seen it in + + + align:start position:0% +also a madeup term. I haven't seen it in +the literature because it's a little bit + + align:start position:0% +the literature because it's a little bit + + + align:start position:0% +the literature because it's a little bit +vague what it could mean. Uh but let's + + align:start position:0% +vague what it could mean. Uh but let's + + + align:start position:0% +vague what it could mean. Uh but let's +say we're given a planer + + align:start position:0% + + + + align:start position:0% + +uh directed as cyclic circuit + + align:start position:0% + + + + align:start position:0% + +and let's say all gates + + align:start position:0% +and let's say all gates + + + align:start position:0% +and let's say all gates +are NAND + + align:start position:0% + + + + align:start position:0% + +then this is MP complete. + + align:start position:0% + + + + align:start position:0% + +in checking whether a particular + + align:start position:0% +in checking whether a particular + + + align:start position:0% +in checking whether a particular +ah right sorry um and at the end you + + align:start position:0% +ah right sorry um and at the end you + + + align:start position:0% +ah right sorry um and at the end you +want it to be true thank you so you have + + align:start position:0% +want it to be true thank you so you have + + + align:start position:0% +want it to be true thank you so you have +the let's say the sources are + + align:start position:0% +the let's say the sources are + + + align:start position:0% +the let's say the sources are +unconstrained + + align:start position:0% + + + + align:start position:0% + +so those represent the variables and + + align:start position:0% +so those represent the variables and + + + align:start position:0% +so those represent the variables and +there's a sync + + align:start position:0% +there's a sync + + + align:start position:0% +there's a sync +which is set to one and we can say + + align:start position:0% +which is set to one and we can say + + + align:start position:0% +which is set to one and we can say +there's just one sync. So you have some + + align:start position:0% +there's just one sync. So you have some + + + align:start position:0% +there's just one sync. So you have some +starting points. Those are completely + + align:start position:0% +starting points. Those are completely + + + align:start position:0% +starting points. Those are completely +free to choose true or false. And then + + align:start position:0% +free to choose true or false. And then + + + align:start position:0% +free to choose true or false. And then +at the end you have a sync. Uh I guess + + align:start position:0% +at the end you have a sync. Uh I guess + + + align:start position:0% +at the end you have a sync. Uh I guess +it just has one thing probably coming + + align:start position:0% +it just has one thing probably coming + + + align:start position:0% +it just has one thing probably coming +into it. Wouldn't make sense otherwise. + + align:start position:0% +into it. Wouldn't make sense otherwise. + + + align:start position:0% +into it. Wouldn't make sense otherwise. +And we set this to be one. So that's + + align:start position:0% +And we set this to be one. So that's + + + align:start position:0% +And we set this to be one. So that's +just like satisfying a formula but drawn + + align:start position:0% +just like satisfying a formula but drawn + + + align:start position:0% +just like satisfying a formula but drawn +as a boolean circuit. And it's planer. + + align:start position:0% +as a boolean circuit. And it's planer. + + + align:start position:0% +as a boolean circuit. And it's planer. +Okay. Now we're going to see more + + align:start position:0% +Okay. Now we're going to see more + + + align:start position:0% +Okay. Now we're going to see more +versions of planer sat next class. Uh + + align:start position:0% +versions of planer sat next class. Uh + + + align:start position:0% +versions of planer sat next class. Uh +but this one as far as I know is newish. + + align:start position:0% +but this one as far as I know is newish. + + + align:start position:0% +but this one as far as I know is newish. +I mean it's obvious it's essentially + + align:start position:0% +I mean it's obvious it's essentially + + + align:start position:0% +I mean it's obvious it's essentially +argued in this paper say hey look um + + align:start position:0% +argued in this paper say hey look um + + + align:start position:0% +argued in this paper say hey look um +this paper was not talking about NP + + align:start position:0% +this paper was not talking about NP + + + align:start position:0% +this paper was not talking about NP +completeness but uh the K paper uh says + + align:start position:0% +completeness but uh the K paper uh says + + + align:start position:0% +completeness but uh the K paper uh says +hey we've got these two things so as + + align:start position:0% +hey we've got these two things so as + + + align:start position:0% +hey we've got these two things so as +long as you have NAND you've got + + align:start position:0% +long as you have NAND you've got + + + align:start position:0% +long as you have NAND you've got +crossovers for free so you don't have to + + align:start position:0% +crossovers for free so you don't have to + + + align:start position:0% +crossovers for free so you don't have to +worry about planerity which is good + + align:start position:0% +worry about planerity which is good + + + align:start position:0% +worry about planerity which is good +news. So no crossover gadget needed + + align:start position:0% +news. So no crossover gadget needed + + + align:start position:0% +news. So no crossover gadget needed +there is one. It's actually not that + + align:start position:0% +there is one. It's actually not that + + + align:start position:0% +there is one. It's actually not that +hard in mind sweeper but it's nicer when + + align:start position:0% +hard in mind sweeper but it's nicer when + + + align:start position:0% +hard in mind sweeper but it's nicer when +you don't have to do it. + + align:start position:0% +you don't have to do it. + + + align:start position:0% +you don't have to do it. +questions. + + align:start position:0% +questions. + + + align:start position:0% +questions. +I guess I did talk about termination. + + align:start position:0% +I guess I did talk about termination. + + + align:start position:0% +I guess I did talk about termination. +Uh but if you we do need a true + + align:start position:0% +Uh but if you we do need a true + + + align:start position:0% +Uh but if you we do need a true +terminator here because we're doing + + align:start position:0% +terminator here because we're doing + + + align:start position:0% +terminator here because we're doing +circuit set that's really easy. Um in + + align:start position:0% +circuit set that's really easy. Um in + + + align:start position:0% +circuit set that's really easy. Um in +fact this would do it. Just ending with + + align:start position:0% +fact this would do it. Just ending with + + + align:start position:0% +fact this would do it. Just ending with +all ones means in fact you have if + + align:start position:0% +all ones means in fact you have if + + + align:start position:0% +all ones means in fact you have if +there's zeros out here that means this + + align:start position:0% +there's zeros out here that means this + + + align:start position:0% +there's zeros out here that means this +has to be a bomb and so that sets it to + + align:start position:0% +has to be a bomb and so that sets it to + + + align:start position:0% +has to be a bomb and so that sets it to +one. So there's a true terminator for + + align:start position:0% +one. So there's a true terminator for + + + align:start position:0% +one. So there's a true terminator for +mind sweeper consistency. But as we've + + align:start position:0% +mind sweeper consistency. But as we've + + + align:start position:0% +mind sweeper consistency. But as we've +seen in various ways mind Mind sweeper + + align:start position:0% +seen in various ways mind Mind sweeper + + + align:start position:0% +seen in various ways mind Mind sweeper +consistency is probably not what we want + + align:start position:0% +consistency is probably not what we want + + + align:start position:0% +consistency is probably not what we want +uh to actually play the game. Um the + + align:start position:0% +uh to actually play the game. Um the + + + align:start position:0% +uh to actually play the game. Um the +algorithm I gave you is maybe is one way + + align:start position:0% +algorithm I gave you is maybe is one way + + + align:start position:0% +algorithm I gave you is maybe is one way +to think about playing the game where + + align:start position:0% +to think about playing the game where + + + align:start position:0% +to think about playing the game where +you're you add a thing and you check for + + align:start position:0% +you're you add a thing and you check for + + + align:start position:0% +you're you add a thing and you check for +consistency. U that's also a little bit + + align:start position:0% +consistency. U that's also a little bit + + + align:start position:0% +consistency. U that's also a little bit +weird where you're just where you're + + align:start position:0% +weird where you're just where you're + + + align:start position:0% +weird where you're just where you're +assuming that the input is consistent + + align:start position:0% +assuming that the input is consistent + + + align:start position:0% +assuming that the input is consistent +and then you add one bomb and you want + + align:start position:0% +and then you add one bomb and you want + + + align:start position:0% +and then you add one bomb and you want +to see whether that makes it + + align:start position:0% +to see whether that makes it + + + align:start position:0% +to see whether that makes it +inconsistent. That's a special case of + + align:start position:0% +inconsistent. That's a special case of + + + align:start position:0% +inconsistent. That's a special case of +this instance. Maybe not as hard as the + + align:start position:0% +this instance. Maybe not as hard as the + + + align:start position:0% +this instance. Maybe not as hard as the +general picture. everything was + + align:start position:0% +general picture. everything was + + + align:start position:0% +general picture. everything was +consistent up until the moment you added + + align:start position:0% +consistent up until the moment you added + + + align:start position:0% +consistent up until the moment you added +one new bomb information. These pictures + + align:start position:0% +one new bomb information. These pictures + + + align:start position:0% +one new bomb information. These pictures +don't look exactly like that. Uh, + + align:start position:0% +don't look exactly like that. Uh, + + + align:start position:0% +don't look exactly like that. Uh, +another thing I want to point out in + + align:start position:0% +another thing I want to point out in + + + align:start position:0% +another thing I want to point out in +these uh, gadgets + + align:start position:0% +these uh, gadgets + + + align:start position:0% +these uh, gadgets +is that the let's say the number of x + + align:start position:0% +is that the let's say the number of x + + + align:start position:0% +is that the let's say the number of x +and x bars is not the same. Maybe this + + align:start position:0% +and x bars is not the same. Maybe this + + + align:start position:0% +and x bars is not the same. Maybe this +negation uh, there's equal numbers of x + + align:start position:0% +negation uh, there's equal numbers of x + + + align:start position:0% +negation uh, there's equal numbers of x +and x bars over here, but there's one + + align:start position:0% +and x bars over here, but there's one + + + align:start position:0% +and x bars over here, but there's one +extra xar. What that means is local to + + align:start position:0% +extra xar. What that means is local to + + + align:start position:0% +extra xar. What that means is local to +this picture, uh, the number of bombs + + align:start position:0% +this picture, uh, the number of bombs + + + align:start position:0% +this picture, uh, the number of bombs +that get used varies, right? There's + + align:start position:0% +that get used varies, right? There's + + + align:start position:0% +that get used varies, right? There's +either one, two, three, four bombs if + + align:start position:0% +either one, two, three, four bombs if + + + align:start position:0% +either one, two, three, four bombs if +you choose X or there's five bombs if + + align:start position:0% +you choose X or there's five bombs if + + + align:start position:0% +you choose X or there's five bombs if +you choose XAR. And one of the minor + + align:start position:0% +you choose XAR. And one of the minor + + + align:start position:0% +you choose XAR. And one of the minor +things in mind sweeper is that the + + align:start position:0% +things in mind sweeper is that the + + + align:start position:0% +things in mind sweeper is that the +number of total number of bombs is given + + align:start position:0% +number of total number of bombs is given + + + align:start position:0% +number of total number of bombs is given +to you as input. Uh, so that actually + + align:start position:0% +to you as input. Uh, so that actually + + + align:start position:0% +to you as input. Uh, so that actually +also kind of messes things up. Um, + + align:start position:0% +also kind of messes things up. Um, + + + align:start position:0% +also kind of messes things up. Um, +anyway, luckily this problem is solved. + + align:start position:0% +anyway, luckily this problem is solved. + + + align:start position:0% +anyway, luckily this problem is solved. +uh is actually independently solved by + + align:start position:0% +uh is actually independently solved by + + + align:start position:0% +uh is actually independently solved by +multiple people. Uh it's claimed in um + + align:start position:0% +multiple people. Uh it's claimed in um + + + align:start position:0% +multiple people. Uh it's claimed in um +in Bob Hearn's PhD thesis, though it + + align:start position:0% +in Bob Hearn's PhD thesis, though it + + + align:start position:0% +in Bob Hearn's PhD thesis, though it +never got fully written up. Uh and then + + align:start position:0% +never got fully written up. Uh and then + + + align:start position:0% +never got fully written up. Uh and then +it got published, so there's no reason + + align:start position:0% +it got published, so there's no reason + + + align:start position:0% +it got published, so there's no reason +to write it up anymore. Uh so here is + + align:start position:0% +to write it up anymore. Uh so here is + + + align:start position:0% +to write it up anymore. Uh so here is +their proof. Uh both this proof and the + + align:start position:0% +their proof. Uh both this proof and the + + + align:start position:0% +their proof. Uh both this proof and the +previous one appeared in mathematical + + align:start position:0% +previous one appeared in mathematical + + + align:start position:0% +previous one appeared in mathematical +intelligencer. Um so they draw the + + align:start position:0% +intelligencer. Um so they draw the + + + align:start position:0% +intelligencer. Um so they draw the +gadget slightly differently and so far + + align:start position:0% +gadget slightly differently and so far + + + align:start position:0% +gadget slightly differently and so far +everything looks about the same. They're + + align:start position:0% +everything looks about the same. They're + + + align:start position:0% +everything looks about the same. They're +not going to use a phase changer in this + + align:start position:0% +not going to use a phase changer in this + + + align:start position:0% +not going to use a phase changer in this +form at least. Uh so they're going to + + align:start position:0% +form at least. Uh so they're going to + + + align:start position:0% +form at least. Uh so they're going to +draw the wire gadget like this and the + + align:start position:0% +draw the wire gadget like this and the + + + align:start position:0% +draw the wire gadget like this and the +idea is that you would copy it. You get + + align:start position:0% +idea is that you would copy it. You get + + + align:start position:0% +idea is that you would copy it. You get +things mod 3. Uh that will turn out to + + align:start position:0% +things mod 3. Uh that will turn out to + + + align:start position:0% +things mod 3. Uh that will turn out to +be okay for them. But what they really + + align:start position:0% +be okay for them. But what they really + + + align:start position:0% +be okay for them. But what they really +want is that in each diagram there an + + align:start position:0% +want is that in each diagram there an + + + align:start position:0% +want is that in each diagram there an +equal number of x and x bars. Why? And + + align:start position:0% +equal number of x and x bars. Why? And + + + align:start position:0% +equal number of x and x bars. Why? And +also what are they proving? So this is + + align:start position:0% +also what are they proving? So this is + + + align:start position:0% +also what are they proving? So this is +uh what they call the + + align:start position:0% +uh what they call the + + + align:start position:0% +uh what they call the +mind sweeper inference problem. + + align:start position:0% + + + + align:start position:0% + +But it's also what you might just call + + align:start position:0% +But it's also what you might just call + + + align:start position:0% +But it's also what you might just call +mind sweeper. + + align:start position:0% +mind sweeper. + + + align:start position:0% +mind sweeper. +I want to solve this puzzle. What does + + align:start position:0% +I want to solve this puzzle. What does + + + align:start position:0% +I want to solve this puzzle. What does +it mean to solve the puzzle? Well, it + + align:start position:0% +it mean to solve the puzzle? Well, it + + + align:start position:0% +it mean to solve the puzzle? Well, it +means you're given this partial + + align:start position:0% +means you're given this partial + + + align:start position:0% +means you're given this partial +information. You want to know, am I + + align:start position:0% +information. You want to know, am I + + + align:start position:0% +information. You want to know, am I +done? Did I solve it? Can I solve it? + + align:start position:0% +done? Did I solve it? Can I solve it? + + + align:start position:0% +done? Did I solve it? Can I solve it? +Can I figure out where all the bombs + + align:start position:0% +Can I figure out where all the bombs + + + align:start position:0% +Can I figure out where all the bombs +are? This is like there being a unique + + align:start position:0% +are? This is like there being a unique + + + align:start position:0% +are? This is like there being a unique +solution. Um, so I want to conclude that + + align:start position:0% +solution. Um, so I want to conclude that + + + align:start position:0% +solution. Um, so I want to conclude that +okay, I can figure out where all the + + align:start position:0% +okay, I can figure out where all the + + + align:start position:0% +okay, I can figure out where all the +bombs are. + + align:start position:0% +bombs are. + + + align:start position:0% +bombs are. +So, + + align:start position:0% + + + + align:start position:0% + +can you figure everything out? + + align:start position:0% + + + + align:start position:0% + +Okay. So again, uh the reduction is from + + align:start position:0% +Okay. So again, uh the reduction is from + + + align:start position:0% +Okay. So again, uh the reduction is from +something like circuit SAT. Uh it's + + align:start position:0% +something like circuit SAT. Uh it's + + + align:start position:0% +something like circuit SAT. Uh it's +going to be a reduction from circuit + + align:start position:0% +going to be a reduction from circuit + + + align:start position:0% +going to be a reduction from circuit +unsat. + + align:start position:0% + + + + align:start position:0% + +unsatisfiability. + + align:start position:0% +unsatisfiability. + + + align:start position:0% +unsatisfiability. +So satisfiability, you want to set the + + align:start position:0% +So satisfiability, you want to set the + + + align:start position:0% +So satisfiability, you want to set the +variable so that the outcome is true. + + align:start position:0% +variable so that the outcome is true. + + + align:start position:0% +variable so that the outcome is true. +You might say, well, I could try to set + + align:start position:0% +You might say, well, I could try to set + + + align:start position:0% +You might say, well, I could try to set +the variable so the outcome is false. + + align:start position:0% +the variable so the outcome is false. + + + align:start position:0% +the variable so the outcome is false. +That's the same problem. Uh that won't + + align:start position:0% +That's the same problem. Uh that won't + + + align:start position:0% +That's the same problem. Uh that won't +change anything. You just put a knot at + + align:start position:0% +change anything. You just put a knot at + + + align:start position:0% +change anything. You just put a knot at +the end. Okay. Unsatisfiability means + + align:start position:0% +the end. Okay. Unsatisfiability means + + + align:start position:0% +the end. Okay. Unsatisfiability means +that you cannot satisfy this formula. + + align:start position:0% +that you cannot satisfy this formula. + + + align:start position:0% +that you cannot satisfy this formula. +There's no way to set the variables to + + align:start position:0% +There's no way to set the variables to + + + align:start position:0% +There's no way to set the variables to +make the output true. + + align:start position:0% +make the output true. + + + align:start position:0% +make the output true. +There is no + + align:start position:0% +There is no + + + align:start position:0% +There is no +there does not exist uh choices for the + + align:start position:0% +there does not exist uh choices for the + + + align:start position:0% +there does not exist uh choices for the +xns + + align:start position:0% +xns + + + align:start position:0% +xns +such that sum f of + + align:start position:0% +such that sum f of + + + align:start position:0% +such that sum f of +x i's uh equals 1. + + align:start position:0% +x i's uh equals 1. + + + align:start position:0% +x i's uh equals 1. +If we do some sort of I don't know if + + align:start position:0% +If we do some sort of I don't know if + + + align:start position:0% +If we do some sort of I don't know if +this is called deorggan probably not uh + + align:start position:0% + + + + align:start position:0% + +another fun fact is uh not there exists + + align:start position:0% +another fun fact is uh not there exists + + + align:start position:0% +another fun fact is uh not there exists +not is the same thing as for all or + + align:start position:0% +not is the same thing as for all or + + + align:start position:0% +not is the same thing as for all or +however you want to write it. Um so if + + align:start position:0% +however you want to write it. Um so if + + + align:start position:0% +however you want to write it. Um so if +we put this negation over to here uh + + align:start position:0% +we put this negation over to here uh + + + align:start position:0% +we put this negation over to here uh +this turns into uni universal + + align:start position:0% +this turns into uni universal + + + align:start position:0% +this turns into uni universal +quantifiers. These are existential + + align:start position:0% +quantifiers. These are existential + + + align:start position:0% +quantifiers. These are existential +quantifiers to for alls. Uh so this is + + align:start position:0% +quantifiers to for alls. Uh so this is + + + align:start position:0% +quantifiers to for alls. Uh so this is +quite a different problem right is about + + align:start position:0% +quite a different problem right is about + + + align:start position:0% +quite a different problem right is about +do there exist the settings for these n + + align:start position:0% +do there exist the settings for these n + + + align:start position:0% +do there exist the settings for these n +variables such that this comes out to be + + align:start position:0% +variables such that this comes out to be + + + align:start position:0% +variables such that this comes out to be +true. Uh now we're saying for no matter + + align:start position:0% +true. Uh now we're saying for no matter + + + align:start position:0% +true. Uh now we're saying for no matter +how you set the variables this comes out + + align:start position:0% +how you set the variables this comes out + + + align:start position:0% +how you set the variables this comes out +to be true or false I guess. But again + + align:start position:0% +to be true or false I guess. But again + + + align:start position:0% +to be true or false I guess. But again +that doesn't matter. You can just put + + align:start position:0% +that doesn't matter. You can just put + + + align:start position:0% +that doesn't matter. You can just put +the negation inside f if you wanted to. + + align:start position:0% +the negation inside f if you wanted to. + + + align:start position:0% +the negation inside f if you wanted to. +So the key difference here is we switch + + align:start position:0% +So the key difference here is we switch + + + align:start position:0% +So the key difference here is we switch +the quantifier direction. This is such a + + align:start position:0% +the quantifier direction. This is such a + + + align:start position:0% +the quantifier direction. This is such a +big difference that this problem is not + + align:start position:0% +big difference that this problem is not + + + align:start position:0% +big difference that this problem is not +nplete unless np equals cop. Uh this + + align:start position:0% +nplete unless np equals cop. Uh this + + + align:start position:0% +nplete unless np equals cop. Uh this +problem is co-enpe. + + align:start position:0% + + + + align:start position:0% + +Okay. Uh recall co-enp are the problems + + align:start position:0% +Okay. Uh recall co-enp are the problems + + + align:start position:0% +Okay. Uh recall co-enp are the problems +where uh it's easy you can always give a + + align:start position:0% +where uh it's easy you can always give a + + + align:start position:0% +where uh it's easy you can always give a +no certificate. Whenever the answer is + + align:start position:0% +no certificate. Whenever the answer is + + + align:start position:0% +no certificate. Whenever the answer is +no, I can give you a short proof that + + align:start position:0% +no, I can give you a short proof that + + + align:start position:0% +no, I can give you a short proof that +the answer is no. How would I tell you + + align:start position:0% +the answer is no. How would I tell you + + + align:start position:0% +the answer is no. How would I tell you +that the answer to this question is no, + + align:start position:0% +that the answer to this question is no, + + + align:start position:0% +that the answer to this question is no, +I would give you a satisfying assignment + + align:start position:0% +I would give you a satisfying assignment + + + align:start position:0% +I would give you a satisfying assignment +and give you x1 through xn where f ends + + align:start position:0% +and give you x1 through xn where f ends + + + align:start position:0% +and give you x1 through xn where f ends +up being one. Then you know this is not + + align:start position:0% +up being one. Then you know this is not + + + align:start position:0% +up being one. Then you know this is not +true. It's very hard to prove yes here. + + align:start position:0% +true. It's very hard to prove yes here. + + + align:start position:0% +true. It's very hard to prove yes here. +You'd have I mean you might have to + + align:start position:0% +You'd have I mean you might have to + + + align:start position:0% +You'd have I mean you might have to +check all possible exponentially many + + align:start position:0% +check all possible exponentially many + + + align:start position:0% +check all possible exponentially many +assignments to the xis. Of course, we + + align:start position:0% +assignments to the xis. Of course, we + + + align:start position:0% +assignments to the xis. Of course, we +don't know whether that's possible. + + align:start position:0% +don't know whether that's possible. + + + align:start position:0% +don't know whether that's possible. +That's compp completeness. It's the same + + align:start position:0% +That's compp completeness. It's the same + + + align:start position:0% +That's compp completeness. It's the same +NP versus uh P problem but negated. + + align:start position:0% +NP versus uh P problem but negated. + + + align:start position:0% +NP versus uh P problem but negated. +Cool. Uh so claim is mind sweeper + + align:start position:0% +Cool. Uh so claim is mind sweeper + + + align:start position:0% +Cool. Uh so claim is mind sweeper +inference is compplete and in general + + align:start position:0% +inference is compplete and in general + + + align:start position:0% +inference is compplete and in general +the proper statement is mind sweeper is + + align:start position:0% +the proper statement is mind sweeper is + + + align:start position:0% +the proper statement is mind sweeper is +compp complete. Uh it's mind sweeper + + align:start position:0% +compp complete. Uh it's mind sweeper + + + align:start position:0% +compp complete. Uh it's mind sweeper +uh consistency is npmplete but mind + + align:start position:0% +uh consistency is npmplete but mind + + + align:start position:0% +uh consistency is npmplete but mind +sweeper the game I want to solve the + + align:start position:0% +sweeper the game I want to solve the + + + align:start position:0% +sweeper the game I want to solve the +game is compp complete. Cool. Uh this + + align:start position:0% +game is compp complete. Cool. Uh this + + + align:start position:0% +game is compp complete. Cool. Uh this +will be one of the few cases where co + + align:start position:0% +will be one of the few cases where co + + + align:start position:0% +will be one of the few cases where co +arises for us. + + align:start position:0% + + + + align:start position:0% + +Yeah. + + align:start position:0% +Yeah. + + + align:start position:0% +Yeah. +Where does co lie on? We don't know + + align:start position:0% +Where does co lie on? We don't know + + + align:start position:0% +Where does co lie on? We don't know +where + + align:start position:0% +where + + + align:start position:0% +where +uh in my one-dimensional diagram you can + + align:start position:0% +uh in my one-dimensional diagram you can + + + align:start position:0% +uh in my one-dimensional diagram you can +think of NP and comp lying in the same + + align:start position:0% +think of NP and comp lying in the same + + + align:start position:0% +think of NP and comp lying in the same +space but maybe like in a parallel + + align:start position:0% +space but maybe like in a parallel + + + align:start position:0% +space but maybe like in a parallel +universe. + + align:start position:0% + + + + align:start position:0% + +I think uh people always draw this + + align:start position:0% +I think uh people always draw this + + + align:start position:0% +I think uh people always draw this +picture of uh + + align:start position:0% +picture of uh + + + align:start position:0% +picture of uh +NP co-enp + + align:start position:0% +NP co-enp + + + align:start position:0% +NP co-enp +uh P is here and this is NP intersect + + align:start position:0% +uh P is here and this is NP intersect + + + align:start position:0% +uh P is here and this is NP intersect +co-enp + + align:start position:0% +co-enp + + + align:start position:0% +co-enp +who knows um so it's it's really off + + align:start position:0% +who knows um so it's it's really off + + + align:start position:0% +who knows um so it's it's really off +it's there are parallel universes one + + align:start position:0% +it's there are parallel universes one + + + align:start position:0% +it's there are parallel universes one +about positive problems one about + + align:start position:0% +about positive problems one about + + + align:start position:0% +about positive problems one about +negative problems + + align:start position:0% +negative problems + + + align:start position:0% +negative problems +uh but in some sense equal complexity if + + align:start position:0% +uh but in some sense equal complexity if + + + align:start position:0% +uh but in some sense equal complexity if +you Think about when we in this class we + + align:start position:0% +you Think about when we in this class we + + + align:start position:0% +you Think about when we in this class we +think about reductions as being one call + + align:start position:0% +think about reductions as being one call + + + align:start position:0% +think about reductions as being one call +reductions. You take your problem you + + align:start position:0% +reductions. You take your problem you + + + align:start position:0% +reductions. You take your problem you +map it so that the output uh when you + + align:start position:0% +map it so that the output uh when you + + + align:start position:0% +map it so that the output uh when you +solve this new problem it has exactly + + align:start position:0% +solve this new problem it has exactly + + + align:start position:0% +solve this new problem it has exactly +the same solution to your original + + align:start position:0% +the same solution to your original + + + align:start position:0% +the same solution to your original +problem. If you instead think about + + align:start position:0% +problem. If you instead think about + + + align:start position:0% +problem. If you instead think about +multiol reductions where you can make + + align:start position:0% +multiol reductions where you can make + + + align:start position:0% +multiol reductions where you can make +calls to an oracle that solve the target + + align:start position:0% +calls to an oracle that solve the target + + + align:start position:0% +calls to an oracle that solve the target +problem multiple times and then do stuff + + align:start position:0% +problem multiple times and then do stuff + + + align:start position:0% +problem multiple times and then do stuff +with it. You could for example call that + + align:start position:0% +with it. You could for example call that + + + align:start position:0% +with it. You could for example call that +thing then negate the answer and return + + align:start position:0% +thing then negate the answer and return + + + align:start position:0% +thing then negate the answer and return +that. In that universe, NP and Comp + + align:start position:0% +that. In that universe, NP and Comp + + + align:start position:0% +that. In that universe, NP and Comp +become the same thing or NP completeness + + align:start position:0% +become the same thing or NP completeness + + + align:start position:0% +become the same thing or NP completeness +and co-enpesseness which are about + + align:start position:0% +and co-enpesseness which are about + + + align:start position:0% +and co-enpesseness which are about +reductions become the same thing. So + + align:start position:0% +reductions become the same thing. So + + + align:start position:0% +reductions become the same thing. So +that's the only thing holding them apart + + align:start position:0% +that's the only thing holding them apart + + + align:start position:0% +that's the only thing holding them apart +is that we're not allowed to negate the + + align:start position:0% +is that we're not allowed to negate the + + + align:start position:0% +is that we're not allowed to negate the +answer. So I view them as almost the + + align:start position:0% +answer. So I view them as almost the + + + align:start position:0% +answer. So I view them as almost the +same but obviously they're different and + + align:start position:0% +same but obviously they're different and + + + align:start position:0% +same but obviously they're different and +you have to distinguish one from the + + align:start position:0% +you have to distinguish one from the + + + align:start position:0% +you have to distinguish one from the +other. But in terms of difficulty + + align:start position:0% +other. But in terms of difficulty + + + align:start position:0% +other. But in terms of difficulty +they're about the same like difference + + align:start position:0% +they're about the same like difference + + + align:start position:0% +they're about the same like difference +between NP and co-enpace is totally + + align:start position:0% +between NP and co-enpace is totally + + + align:start position:0% +between NP and co-enpace is totally +different or X time or you know other + + align:start position:0% +different or X time or you know other + + + align:start position:0% +different or X time or you know other +things in my onedimensional diagram. + + align:start position:0% +things in my onedimensional diagram. + + + align:start position:0% +things in my onedimensional diagram. +Yeah. Would P equals NP imply P equals + + align:start position:0% +Yeah. Would P equals NP imply P equals + + + align:start position:0% +Yeah. Would P equals NP imply P equals +Coen NP? If p equals np then I'm pretty + + align:start position:0% +Coen NP? If p equals np then I'm pretty + + + align:start position:0% +Coen NP? If p equals np then I'm pretty +sure co uh np equals co p uh because + + align:start position:0% +sure co uh np equals co p uh because + + + align:start position:0% +sure co uh np equals co p uh because +under in polinomial time you can do yeah + + align:start position:0% +under in polinomial time you can do yeah + + + align:start position:0% +under in polinomial time you can do yeah +p is closed under complement because you + + align:start position:0% +p is closed under complement because you + + + align:start position:0% +p is closed under complement because you +can just solve the problem that negate + + align:start position:0% +can just solve the problem that negate + + + align:start position:0% +can just solve the problem that negate +so I should say np and compp are + + align:start position:0% +so I should say np and compp are + + + align:start position:0% +so I should say np and compp are +different but nplete and comp complete + + align:start position:0% +different but nplete and comp complete + + + align:start position:0% +different but nplete and comp complete +are very close let's say they're you + + align:start position:0% +are very close let's say they're you + + + align:start position:0% +are very close let's say they're you +know this they're sort of dual for every + + align:start position:0% +know this they're sort of dual for every + + + align:start position:0% +know this they're sort of dual for every +problem over here is a corresponding + + align:start position:0% +problem over here is a corresponding + + + align:start position:0% +problem over here is a corresponding +problem over here is like the hardest + + align:start position:0% +problem over here is like the hardest + + + align:start position:0% +problem over here is like the hardest +and they're sort of symmetric or + + align:start position:0% +and they're sort of symmetric or + + + align:start position:0% +and they're sort of symmetric or +something. + + align:start position:0% + + + + align:start position:0% + +All right, + + align:start position:0% +All right, + + + align:start position:0% +All right, +back to mind sweeper. So, uh here is the + + align:start position:0% +back to mind sweeper. So, uh here is the + + + align:start position:0% +back to mind sweeper. So, uh here is the +compp completeness. We have wires just + + align:start position:0% +compp completeness. We have wires just + + + align:start position:0% +compp completeness. We have wires just +like before, but I'm drawing them + + align:start position:0% +like before, but I'm drawing them + + + align:start position:0% +like before, but I'm drawing them +differently because uh part of the issue + + align:start position:0% +differently because uh part of the issue + + + align:start position:0% +differently because uh part of the issue +here is we are told how many bombs there + + align:start position:0% +here is we are told how many bombs there + + + align:start position:0% +here is we are told how many bombs there +are and we don't want that information + + align:start position:0% +are and we don't want that information + + + align:start position:0% +are and we don't want that information +to help us. So, we want every diagram to + + align:start position:0% +to help us. So, we want every diagram to + + + align:start position:0% +to help us. So, we want every diagram to +have an equal number of say x and x + + align:start position:0% +have an equal number of say x and x + + + align:start position:0% +have an equal number of say x and x +bars. So if we set it with X or set it + + align:start position:0% +bars. So if we set it with X or set it + + + align:start position:0% +bars. So if we set it with X or set it +with XAR, we use exactly the same number + + align:start position:0% +with XAR, we use exactly the same number + + + align:start position:0% +with XAR, we use exactly the same number +of bombs, which means just knowing what + + align:start position:0% +of bombs, which means just knowing what + + + align:start position:0% +of bombs, which means just knowing what +gadgets are glued together, we can just + + align:start position:0% +gadgets are glued together, we can just + + + align:start position:0% +gadgets are glued together, we can just +add up how many bombs each one has, that + + align:start position:0% +add up how many bombs each one has, that + + + align:start position:0% +add up how many bombs each one has, that +will be the total number of bombs given + + align:start position:0% +will be the total number of bombs given + + + align:start position:0% +will be the total number of bombs given +to the puzzle. Um, and that shouldn't + + align:start position:0% +to the puzzle. Um, and that shouldn't + + + align:start position:0% +to the puzzle. Um, and that shouldn't +give you any extra information because + + align:start position:0% +give you any extra information because + + + align:start position:0% +give you any extra information because +all of these pictures will have equal + + align:start position:0% +all of these pictures will have equal + + + align:start position:0% +all of these pictures will have equal +number of X's and X bars. So here we + + align:start position:0% +number of X's and X bars. So here we + + + align:start position:0% +number of X's and X bars. So here we +have wire, terminator, and turn. pretty + + align:start position:0% +have wire, terminator, and turn. pretty + + + align:start position:0% +have wire, terminator, and turn. pretty +similar to before but now checking that + + align:start position:0% +similar to before but now checking that + + + align:start position:0% +similar to before but now checking that +everything has equal number of x's and x + + align:start position:0% +everything has equal number of x's and x + + + align:start position:0% +everything has equal number of x's and x +bars. I think this turn for example that + + align:start position:0% +bars. I think this turn for example that + + + align:start position:0% +bars. I think this turn for example that +one happens to be balanced but some of + + align:start position:0% +one happens to be balanced but some of + + + align:start position:0% +one happens to be balanced but some of +these gadgets are not balanced. This one + + align:start position:0% +these gadgets are not balanced. This one + + + align:start position:0% +these gadgets are not balanced. This one +almost certainly. + + align:start position:0% +almost certainly. + + + align:start position:0% +almost certainly. +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +So um in this case they construct + + align:start position:0% +So um in this case they construct + + + align:start position:0% +So um in this case they construct +a notgate and an orgate and then uh they + + align:start position:0% +a notgate and an orgate and then uh they + + + align:start position:0% +a notgate and an orgate and then uh they +also build a shifter. This is a + + align:start position:0% +also build a shifter. This is a + + + align:start position:0% +also build a shifter. This is a +different kind of shifter. um it's + + align:start position:0% +different kind of shifter. um it's + + + align:start position:0% +different kind of shifter. um it's +actually it still has you know width a + + align:start position:0% +actually it still has you know width a + + + align:start position:0% +actually it still has you know width a +multiple of three but we're taking the + + align:start position:0% +multiple of three but we're taking the + + + align:start position:0% +multiple of three but we're taking the +wire and shifting it perpendicular by + + align:start position:0% +wire and shifting it perpendicular by + + + align:start position:0% +wire and shifting it perpendicular by +one unit with turns you can simulate the + + align:start position:0% +one unit with turns you can simulate the + + + align:start position:0% +one unit with turns you can simulate the +other type of shifter but this turns out + + align:start position:0% +other type of shifter but this turns out + + + align:start position:0% +other type of shifter but this turns out +to be the only one that they need uh so + + align:start position:0% +to be the only one that they need uh so + + + align:start position:0% +to be the only one that they need uh so +it's let's let's talk about that first + + align:start position:0% +it's let's let's talk about that first + + + align:start position:0% +it's let's let's talk about that first +let's say so if x is set by this two uh + + align:start position:0% +let's say so if x is set by this two uh + + + align:start position:0% +let's say so if x is set by this two uh +and this bomb this one is not set okay + + align:start position:0% +and this bomb this one is not set okay + + + align:start position:0% +and this bomb this one is not set okay +this four already has three of them so + + align:start position:0% +this four already has three of them so + + + align:start position:0% +this four already has three of them so +it effectively becomes a one so then + + align:start position:0% +it effectively becomes a one so then + + + align:start position:0% +it effectively becomes a one so then +these two have to be opposites from each + + align:start position:0% +these two have to be opposites from each + + + align:start position:0% +these two have to be opposites from each +other. This is sort of where the shift + + align:start position:0% +other. This is sort of where the shift + + + align:start position:0% +other. This is sort of where the shift +happens. Uh and then uh because we have + + align:start position:0% +happens. Uh and then uh because we have + + + align:start position:0% +happens. Uh and then uh because we have +to deal with these bombs that are left + + align:start position:0% +to deal with these bombs that are left + + + align:start position:0% +to deal with these bombs that are left +over, let's put some more in. And then + + align:start position:0% +over, let's put some more in. And then + + + align:start position:0% +over, let's put some more in. And then +this is five. So there's already four + + align:start position:0% +this is five. So there's already four + + + align:start position:0% +this is five. So there's already four +here. And so that forces an alternation + + align:start position:0% +here. And so that forces an alternation + + + align:start position:0% +here. And so that forces an alternation +there. So same idea, but with some bombs + + align:start position:0% +there. So same idea, but with some bombs + + + align:start position:0% +there. So same idea, but with some bombs +added in to uh fill the space. Let's + + align:start position:0% +added in to uh fill the space. Let's + + + align:start position:0% +added in to uh fill the space. Let's +say, could I do a one here and a one + + align:start position:0% +say, could I do a one here and a one + + + align:start position:0% +say, could I do a one here and a one +here? A one there. Uh this is a problem. + + align:start position:0% +here? A one there. Uh this is a problem. + + + align:start position:0% +here? A one there. Uh this is a problem. +I couldn't can't put a one here. That + + align:start position:0% +I couldn't can't put a one here. That + + + align:start position:0% +I couldn't can't put a one here. That +would force this guy to be present. So + + align:start position:0% +would force this guy to be present. So + + + align:start position:0% +would force this guy to be present. So +that's probably why that bomb is there + + align:start position:0% +that's probably why that bomb is there + + + align:start position:0% +that's probably why that bomb is there +because we don't want to have to say how + + align:start position:0% +because we don't want to have to say how + + + align:start position:0% +because we don't want to have to say how +many bombs are adjacent to this corner. + + align:start position:0% +many bombs are adjacent to this corner. + + + align:start position:0% +many bombs are adjacent to this corner. +With regular wires, you don't have + + align:start position:0% +With regular wires, you don't have + + + align:start position:0% +With regular wires, you don't have +corners. Good. But when you're doing + + align:start position:0% +corners. Good. But when you're doing + + + align:start position:0% +corners. Good. But when you're doing +this shift, you have sort of corner. + + align:start position:0% +this shift, you have sort of corner. + + + align:start position:0% +this shift, you have sort of corner. +Same thing with the turn gadget that we + + align:start position:0% +Same thing with the turn gadget that we + + + align:start position:0% +Same thing with the turn gadget that we +already saw. Okay. Uh I think not is + + align:start position:0% +already saw. Okay. Uh I think not is + + + align:start position:0% +already saw. Okay. Uh I think not is +also pretty intelligible, but it's + + align:start position:0% +also pretty intelligible, but it's + + + align:start position:0% +also pretty intelligible, but it's +fairly complicated. It essentially + + align:start position:0% +fairly complicated. It essentially + + + align:start position:0% +fairly complicated. It essentially +involves making another copy of the + + align:start position:0% +involves making another copy of the + + + align:start position:0% +involves making another copy of the +signal just so we get an equal number of + + align:start position:0% +signal just so we get an equal number of + + + align:start position:0% +signal just so we get an equal number of +X's and X bars because we saw in the in + + align:start position:0% +X's and X bars because we saw in the in + + + align:start position:0% +X's and X bars because we saw in the in +the previous reduction with the notgate + + align:start position:0% +the previous reduction with the notgate + + + align:start position:0% +the previous reduction with the notgate +we had this one isolated guy that would + + align:start position:0% +we had this one isolated guy that would + + + align:start position:0% +we had this one isolated guy that would +be like this one and so if you just have + + align:start position:0% +be like this one and so if you just have + + + align:start position:0% +be like this one and so if you just have +this picture uh yeah it would negate + + align:start position:0% +this picture uh yeah it would negate + + + align:start position:0% +this picture uh yeah it would negate +things and and again this is designed to + + align:start position:0% +things and and again this is designed to + + + align:start position:0% +things and and again this is designed to +be mod 3. So there's three six this is + + align:start position:0% +be mod 3. So there's three six this is + + + align:start position:0% +be mod 3. So there's three six this is +hard to do 9 12 15. Okay. So things are + + align:start position:0% +hard to do 9 12 15. Okay. So things are + + + align:start position:0% +hard to do 9 12 15. Okay. So things are +nicely aligned on the mod 3 boundary but + + align:start position:0% +nicely aligned on the mod 3 boundary but + + + align:start position:0% +nicely aligned on the mod 3 boundary but +they end up with these three dudes. Uh + + align:start position:0% +they end up with these three dudes. Uh + + + align:start position:0% +they end up with these three dudes. Uh +they end up flipping the signal. Here's + + align:start position:0% +they end up flipping the signal. Here's + + + align:start position:0% +they end up flipping the signal. Here's +X. Here it's also X which is like the + + align:start position:0% +X. Here it's also X which is like the + + + align:start position:0% +X. Here it's also X which is like the +reverse because it's on the left. Uh + + align:start position:0% +reverse because it's on the left. Uh + + + align:start position:0% +reverse because it's on the left. Uh +but this would have an unequal number of + + align:start position:0% +but this would have an unequal number of + + + align:start position:0% +but this would have an unequal number of +X's and X bars. There's too many X's in + + align:start position:0% +X's and X bars. There's too many X's in + + + align:start position:0% +X's and X bars. There's too many X's in +this row. So uh we end up splitting off + + align:start position:0% +this row. So uh we end up splitting off + + + align:start position:0% +this row. So uh we end up splitting off +a negated copy here basically to balance + + align:start position:0% +a negated copy here basically to balance + + + align:start position:0% +a negated copy here basically to balance +things out. And now if you count all the + + align:start position:0% +things out. And now if you count all the + + + align:start position:0% +things out. And now if you count all the +x's and x bars they should be equal. + + align:start position:0% +x's and x bars they should be equal. + + + align:start position:0% +x's and x bars they should be equal. +Cool. Uh and then they build an orgate. + + align:start position:0% +Cool. Uh and then they build an orgate. + + + align:start position:0% +Cool. Uh and then they build an orgate. +So uh it's again looks fairly + + align:start position:0% +So uh it's again looks fairly + + + align:start position:0% +So uh it's again looks fairly +complicated probably pretty simple in + + align:start position:0% +complicated probably pretty simple in + + + align:start position:0% +complicated probably pretty simple in +essence but I don't feel like checking + + align:start position:0% +essence but I don't feel like checking + + + align:start position:0% +essence but I don't feel like checking +all those cases. Uh what is annoying is + + align:start position:0% +all those cases. Uh what is annoying is + + + align:start position:0% +all those cases. Uh what is annoying is +that this thing is not mod 3 aligned. + + align:start position:0% +that this thing is not mod 3 aligned. + + + align:start position:0% +that this thing is not mod 3 aligned. +Mod 3 aligned would be here or here with + + align:start position:0% +Mod 3 aligned would be here or here with + + + align:start position:0% +Mod 3 aligned would be here or here with +the output always in the middle finger. + + align:start position:0% +the output always in the middle finger. + + + align:start position:0% +the output always in the middle finger. +But instead it's here. And so they use + + align:start position:0% +But instead it's here. And so they use + + + align:start position:0% +But instead it's here. And so they use +the shift gadget over here to offset + + align:start position:0% +the shift gadget over here to offset + + + align:start position:0% +the shift gadget over here to offset +that by one. And similarly in all three + + align:start position:0% +that by one. And similarly in all three + + + align:start position:0% +that by one. And similarly in all three +pictures. Okay. And then you get an + + align:start position:0% +pictures. Okay. And then you get an + + + align:start position:0% +pictures. Okay. And then you get an +orgate with proper alignment. Everything + + align:start position:0% +orgate with proper alignment. Everything + + + align:start position:0% +orgate with proper alignment. Everything +works out mod 3. + + align:start position:0% +works out mod 3. + + + align:start position:0% +works out mod 3. +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +Cool. Uh so we have not and we have or + + align:start position:0% +Cool. Uh so we have not and we have or + + + align:start position:0% +Cool. Uh so we have not and we have or +therefore we have nor and therefore we + + align:start position:0% +therefore we have nor and therefore we + + + align:start position:0% +therefore we have nor and therefore we +can build any uh logical gate we want. + + align:start position:0% +can build any uh logical gate we want. + + + align:start position:0% +can build any uh logical gate we want. +Uh, and so we have turns, + + align:start position:0% +Uh, and so we have turns, + + + align:start position:0% +Uh, and so we have turns, +we have shifts that we need, we have + + align:start position:0% +we have shifts that we need, we have + + + align:start position:0% +we have shifts that we need, we have +not, we have, do we do split? I think we + + align:start position:0% +not, we have, do we do split? I think we + + + align:start position:0% +not, we have, do we do split? I think we +did split on the previous. No, we didn't + + align:start position:0% +did split on the previous. No, we didn't + + + align:start position:0% +did split on the previous. No, we didn't +do split. Okay, then let's do split. Uh, + + align:start position:0% +do split. Okay, then let's do split. Uh, + + + align:start position:0% +do split. Okay, then let's do split. Uh, +so we need to copy our wires. Uh, this + + align:start position:0% +so we need to copy our wires. Uh, this + + + align:start position:0% +so we need to copy our wires. Uh, this +is a more complicated version of the + + align:start position:0% +is a more complicated version of the + + + align:start position:0% +is a more complicated version of the +previous split again with some extra + + align:start position:0% +previous split again with some extra + + + align:start position:0% +previous split again with some extra +things thrown in. Like this is not + + align:start position:0% +things thrown in. Like this is not + + + align:start position:0% +things thrown in. Like this is not +needed. You don't have to put this here, + + align:start position:0% +needed. You don't have to put this here, + + + align:start position:0% +needed. You don't have to put this here, +but it adds an extra XAR. So uh there's + + align:start position:0% +but it adds an extra XAR. So uh there's + + + align:start position:0% +but it adds an extra XAR. So uh there's +actually two of those things and so + + align:start position:0% +actually two of those things and so + + + align:start position:0% +actually two of those things and so +together that offsets all the extra x + + align:start position:0% +together that offsets all the extra x + + + align:start position:0% +together that offsets all the extra x +copies that are on the inside and so + + align:start position:0% +copies that are on the inside and so + + + align:start position:0% +copies that are on the inside and so +that forces uh again equal number of + + align:start position:0% +that forces uh again equal number of + + + align:start position:0% +that forces uh again equal number of +bombs whether it's x or xar chosen. + + align:start position:0% +bombs whether it's x or xar chosen. + + + align:start position:0% +bombs whether it's x or xar chosen. +So uh we can just count how many bombs + + align:start position:0% +So uh we can just count how many bombs + + + align:start position:0% +So uh we can just count how many bombs +are needed in this picture. Uh cool. Uh + + align:start position:0% +are needed in this picture. Uh cool. Uh + + + align:start position:0% +are needed in this picture. Uh cool. Uh +this is again a symmetric version. So if + + align:start position:0% +this is again a symmetric version. So if + + + align:start position:0% +this is again a symmetric version. So if +you're thinking of of let's say this as + + align:start position:0% +you're thinking of of let's say this as + + + align:start position:0% +you're thinking of of let's say this as +the input and these two as the output uh + + align:start position:0% +the input and these two as the output uh + + + align:start position:0% +the input and these two as the output uh +then negation happened. So if you don't + + align:start position:0% +then negation happened. So if you don't + + + align:start position:0% +then negation happened. So if you don't +want negation to happen just put a big + + align:start position:0% +want negation to happen just put a big + + + align:start position:0% +want negation to happen just put a big +not gate there. + + align:start position:0% +not gate there. + + + align:start position:0% +not gate there. +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +And uh in this case they give a + + align:start position:0% +And uh in this case they give a + + + align:start position:0% +And uh in this case they give a +crossover gadget uh in particular + + align:start position:0% +crossover gadget uh in particular + + + align:start position:0% +crossover gadget uh in particular +because it's not that hard to give a + + align:start position:0% +because it's not that hard to give a + + + align:start position:0% +because it's not that hard to give a +crossover gadget but uh it's also not + + align:start position:0% +crossover gadget but uh it's also not + + + align:start position:0% +crossover gadget but uh it's also not +necessary. So you could do crossover + + align:start position:0% +necessary. So you could do crossover + + + align:start position:0% +necessary. So you could do crossover +explicitly but in fact uh I just looked + + align:start position:0% +explicitly but in fact uh I just looked + + + align:start position:0% +explicitly but in fact uh I just looked +on Wikipedia earlier today uh how do you + + align:start position:0% +on Wikipedia earlier today uh how do you + + + align:start position:0% +on Wikipedia earlier today uh how do you +build we already know that planer + + align:start position:0% +build we already know that planer + + + align:start position:0% +build we already know that planer +circuit sat with NAND gates is hard so + + align:start position:0% +circuit sat with NAND gates is hard so + + + align:start position:0% +circuit sat with NAND gates is hard so +can we build NAND and so I looked up in + + align:start position:0% +can we build NAND and so I looked up in + + + align:start position:0% +can we build NAND and so I looked up in +Wikipedia how do you build NAND out of + + align:start position:0% +Wikipedia how do you build NAND out of + + + align:start position:0% +Wikipedia how do you build NAND out of +NORS and the answer is this and that's + + align:start position:0% +NORS and the answer is this and that's + + + align:start position:0% +NORS and the answer is this and that's +planer so we're done so you take this + + align:start position:0% +planer so we're done so you take this + + + align:start position:0% +planer so we're done so you take this +picture you plug it into each of these + + align:start position:0% +picture you plug it into each of these + + + align:start position:0% +picture you plug it into each of these +guys and you take that picture you plug + + align:start position:0% +guys and you take that picture you plug + + + align:start position:0% +guys and you take that picture you plug +it into each of these guys make sure it + + align:start position:0% +it into each of these guys make sure it + + + align:start position:0% +it into each of these guys make sure it +preserves plainerity all the way + + align:start position:0% +preserves plainerity all the way + + + align:start position:0% +preserves plainerity all the way +through. It does. And then from uh I + + align:start position:0% +through. It does. And then from uh I + + + align:start position:0% +through. It does. And then from uh I +should know that's how you construct + + align:start position:0% +should know that's how you construct + + + align:start position:0% +should know that's how you construct +NAND out of NOR. It's exactly from de + + align:start position:0% +NAND out of NOR. It's exactly from de + + + align:start position:0% +NAND out of NOR. It's exactly from de +Morgan's law. Uh because this is just + + align:start position:0% +Morgan's law. Uh because this is just + + + align:start position:0% +Morgan's law. Uh because this is just +negation. So cool thing is all these + + align:start position:0% +negation. So cool thing is all these + + + align:start position:0% +negation. So cool thing is all these +constructions preserve plarity which + + align:start position:0% +constructions preserve plarity which + + + align:start position:0% +constructions preserve plarity which +means we can add to our definition of + + align:start position:0% +means we can add to our definition of + + + align:start position:0% +means we can add to our definition of +planer circuit set. uh all gates are + + align:start position:0% +planer circuit set. uh all gates are + + + align:start position:0% +planer circuit set. uh all gates are +NAND + + align:start position:0% +NAND + + + align:start position:0% +NAND +uh + + align:start position:0% +uh + + + align:start position:0% +uh +or all gates are NOR. + + align:start position:0% + + + + align:start position:0% + +This is nice because when you're solving + + align:start position:0% +This is nice because when you're solving + + + align:start position:0% +This is nice because when you're solving +next P set or whatever uh you can uh + + align:start position:0% +next P set or whatever uh you can uh + + + align:start position:0% +next P set or whatever uh you can uh +just take planer circuits and if you + + align:start position:0% +just take planer circuits and if you + + + align:start position:0% +just take planer circuits and if you +happen to construct an ANDgate you're + + align:start position:0% +happen to construct an ANDgate you're + + + align:start position:0% +happen to construct an ANDgate you're +done. If you happen to construct a + + align:start position:0% +done. If you happen to construct a + + + align:start position:0% +done. If you happen to construct a +norate you're done no crossover needed. + + align:start position:0% +norate you're done no crossover needed. + + + align:start position:0% +norate you're done no crossover needed. +You'll still need turns and maybe a + + align:start position:0% +You'll still need turns and maybe a + + + align:start position:0% +You'll still need turns and maybe a +shift and maybe a terminator. Uh you + + align:start position:0% +shift and maybe a terminator. Uh you + + + align:start position:0% +shift and maybe a terminator. Uh you +won't need not if you build NAND or nor + + align:start position:0% +won't need not if you build NAND or nor + + + align:start position:0% +won't need not if you build NAND or nor +uh you'll need a split, but you don't + + align:start position:0% +uh you'll need a split, but you don't + + + align:start position:0% +uh you'll need a split, but you don't +need a crossover anymore. This is cool + + align:start position:0% +need a crossover anymore. This is cool + + + align:start position:0% +need a crossover anymore. This is cool +as far as I know a new result, but I + + align:start position:0% +as far as I know a new result, but I + + + align:start position:0% +as far as I know a new result, but I +mean obviously implicit in all of these + + align:start position:0% +mean obviously implicit in all of these + + + align:start position:0% +mean obviously implicit in all of these +things. + + align:start position:0% +things. + + + align:start position:0% +things. +Uh yeah. + + align:start position:0% +Uh yeah. + + + align:start position:0% +Uh yeah. +Do you know if there's any um sub + + align:start position:0% +Do you know if there's any um sub + + + align:start position:0% +Do you know if there's any um sub +problem I guess of SAT where you don't + + align:start position:0% +problem I guess of SAT where you don't + + + align:start position:0% +problem I guess of SAT where you don't +have universal gates and you can't be + + align:start position:0% +have universal gates and you can't be + + + align:start position:0% +have universal gates and you can't be +planer and yet it's still hard. + + align:start position:0% +planer and yet it's still hard. + + + align:start position:0% +planer and yet it's still hard. +Uh + + align:start position:0% +Uh + + + align:start position:0% +Uh +so maybe you can you can + + align:start position:0% +so maybe you can you can + + + align:start position:0% +so maybe you can you can +oh interesting + + align:start position:0% +oh interesting + + + align:start position:0% +oh interesting +you can split wires and you have a + + align:start position:0% +you can split wires and you have a + + + align:start position:0% +you can split wires and you have a +variable that has you know the negation + + align:start position:0% +variable that has you know the negation + + + align:start position:0% +variable that has you know the negation +of it coming out but that's all you can + + align:start position:0% +of it coming out but that's all you can + + + align:start position:0% +of it coming out but that's all you can +do no other gates. + + align:start position:0% +do no other gates. + + + align:start position:0% +do no other gates. +Uh + + align:start position:0% +Uh + + + align:start position:0% +Uh +my guess is that all such problems are + + align:start position:0% +my guess is that all such problems are + + + align:start position:0% +my guess is that all such problems are +polomally solvable but maybe that's + + align:start position:0% +polomally solvable but maybe that's + + + align:start position:0% +polomally solvable but maybe that's +something we could think about. Um + + align:start position:0% +something we could think about. Um + + + align:start position:0% +something we could think about. Um +certainly plausible that you don't need + + align:start position:0% +certainly plausible that you don't need + + + align:start position:0% +certainly plausible that you don't need +to be able to construct all boolean + + align:start position:0% +to be able to construct all boolean + + + align:start position:0% +to be able to construct all boolean +formulas in order to be hard but my + + align:start position:0% +formulas in order to be hard but my + + + align:start position:0% +formulas in order to be hard but my +vague sense slash experience playing + + align:start position:0% +vague sense slash experience playing + + + align:start position:0% +vague sense slash experience playing +around with uh other weird other gates + + align:start position:0% +around with uh other weird other gates + + + align:start position:0% +around with uh other weird other gates +most of them are all equivalent to + + align:start position:0% +most of them are all equivalent to + + + align:start position:0% +most of them are all equivalent to +splits if they're not universal. + + align:start position:0% +splits if they're not universal. + + + align:start position:0% +splits if they're not universal. +something like a split. Maybe with some + + align:start position:0% +something like a split. Maybe with some + + + align:start position:0% +something like a split. Maybe with some +like five operand operator, you could do + + align:start position:0% +like five operand operator, you could do + + + align:start position:0% +like five operand operator, you could do +something cool. But uh usually they + + align:start position:0% +something cool. But uh usually they + + + align:start position:0% +something cool. But uh usually they +degenerate to either split-like things + + align:start position:0% +degenerate to either split-like things + + + align:start position:0% +degenerate to either split-like things +or + + align:start position:0% +or + + + align:start position:0% +or +uh clauseike things. But if you don't + + align:start position:0% +uh clauseike things. But if you don't + + + align:start position:0% +uh clauseike things. But if you don't +have both, you don't get enough to be + + align:start position:0% +have both, you don't get enough to be + + + align:start position:0% +have both, you don't get enough to be +hard. We should prove a theorem like + + align:start position:0% +hard. We should prove a theorem like + + + align:start position:0% +hard. We should prove a theorem like +that. But I would guess that you need + + align:start position:0% +that. But I would guess that you need + + + align:start position:0% +that. But I would guess that you need +something like this. Now, these are not + + align:start position:0% +something like this. Now, these are not + + + align:start position:0% +something like this. Now, these are not +the only universal gate sets. I think in + + align:start position:0% +the only universal gate sets. I think in + + + align:start position:0% +the only universal gate sets. I think in +a moment I will have a uh I in if you + + align:start position:0% +a moment I will have a uh I in if you + + + align:start position:0% +a moment I will have a uh I in if you +are curious about more of what universal + + align:start position:0% +are curious about more of what universal + + + align:start position:0% +are curious about more of what universal +gate sets are these are usually called + + align:start position:0% +gate sets are these are usually called + + + align:start position:0% +gate sets are these are usually called +functionally complete or functional + + align:start position:0% +functionally complete or functional + + + align:start position:0% +functionally complete or functional +completeness if you look at that + + align:start position:0% +completeness if you look at that + + + align:start position:0% +completeness if you look at that +Wikipedia this is an excerpt from + + align:start position:0% +Wikipedia this is an excerpt from + + + align:start position:0% +Wikipedia this is an excerpt from +Wikipedia you see NAND andor are the + + align:start position:0% +Wikipedia you see NAND andor are the + + + align:start position:0% +Wikipedia you see NAND andor are the +only among uh two operators so you have + + align:start position:0% +only among uh two operators so you have + + + align:start position:0% +only among uh two operators so you have +two inputs one output um NAND andor the + + align:start position:0% +two inputs one output um NAND andor the + + + align:start position:0% +two inputs one output um NAND andor the +only things that by themselves are + + align:start position:0% +only things that by themselves are + + + align:start position:0% +only things that by themselves are +universal but once you allow two + + align:start position:0% +universal but once you allow two + + + align:start position:0% +universal but once you allow two +different gates you can do other things + + align:start position:0% +different gates you can do other things + + + align:start position:0% +different gates you can do other things +so uh these are particularly + + align:start position:0% +so uh these are particularly + + + align:start position:0% +so uh these are particularly +interesting. This is false, I think. Uh + + align:start position:0% +interesting. This is false, I think. Uh + + + align:start position:0% +interesting. This is false, I think. Uh +it's called bot and this is and this is + + align:start position:0% +it's called bot and this is and this is + + + align:start position:0% +it's called bot and this is and this is +called top. That's true. Um and so uh + + align:start position:0% +called top. That's true. Um and so uh + + + align:start position:0% +called top. That's true. Um and so uh +these are slightly unusual ways for me + + align:start position:0% +these are slightly unusual ways for me + + + align:start position:0% +these are slightly unusual ways for me +to think about writing them. Here we + + align:start position:0% +to think about writing them. Here we + + + align:start position:0% +to think about writing them. Here we +have of course and and not. Um but this + + align:start position:0% +have of course and and not. Um but this + + + align:start position:0% +have of course and and not. Um but this +is this is right implication uh which is + + align:start position:0% +is this is right implication uh which is + + + align:start position:0% +is this is right implication uh which is +like not the left thing or the right + + align:start position:0% +like not the left thing or the right + + + align:start position:0% +like not the left thing or the right +thing. We talked about that in the past. + + align:start position:0% +thing. We talked about that in the past. + + + align:start position:0% +thing. We talked about that in the past. +That by itself is not enough because you + + align:start position:0% +That by itself is not enough because you + + + align:start position:0% +That by itself is not enough because you +can just follow implication change. But + + align:start position:0% +can just follow implication change. But + + + align:start position:0% +can just follow implication change. But +if you also have false that is universal + + align:start position:0% +if you also have false that is universal + + + align:start position:0% +if you also have false that is universal +that's kind of funny. Uh and this is + + align:start position:0% +that's kind of funny. Uh and this is + + + align:start position:0% +that's kind of funny. Uh and this is +exor. I think exor is the same as saying + + align:start position:0% +exor. I think exor is the same as saying + + + align:start position:0% +exor. I think exor is the same as saying +that the two things are different. Um + + align:start position:0% +that the two things are different. Um + + + align:start position:0% +that the two things are different. Um +and this is xnor. So those by themselves + + align:start position:0% +and this is xnor. So those by themselves + + + align:start position:0% +and this is xnor. So those by themselves +are not universal. But if you have some + + align:start position:0% +are not universal. But if you have some + + + align:start position:0% +are not universal. But if you have some +other kind of one-way implication then + + align:start position:0% +other kind of one-way implication then + + + align:start position:0% +other kind of one-way implication then +uh that gives you any logical formulas. + + align:start position:0% +uh that gives you any logical formulas. + + + align:start position:0% +uh that gives you any logical formulas. +Now whether these in the planer version + + align:start position:0% +Now whether these in the planer version + + + align:start position:0% +Now whether these in the planer version +are hard I don't know. But I know that + + align:start position:0% +are hard I don't know. But I know that + + + align:start position:0% +are hard I don't know. But I know that +these in the planer version are hard. + + align:start position:0% +these in the planer version are hard. + + + align:start position:0% +these in the planer version are hard. +Okay, back to mind sweeper. Uh they drew + + align:start position:0% +Okay, back to mind sweeper. Uh they drew + + + align:start position:0% +Okay, back to mind sweeper. Uh they drew +a picture of how everything fits + + align:start position:0% +a picture of how everything fits + + + align:start position:0% +a picture of how everything fits +together. So it's maybe nice to have the + + align:start position:0% +together. So it's maybe nice to have the + + + align:start position:0% +together. So it's maybe nice to have the +big picture. Uh but let's in particular + + align:start position:0% +big picture. Uh but let's in particular + + + align:start position:0% +big picture. Uh but let's in particular +think about what the decision question + + align:start position:0% +think about what the decision question + + + align:start position:0% +think about what the decision question +is and make sure what I mean I claim + + align:start position:0% +is and make sure what I mean I claim + + + align:start position:0% +is and make sure what I mean I claim +this is coenp and that we're doing + + align:start position:0% +this is coenp and that we're doing + + + align:start position:0% +this is coenp and that we're doing +unsat, but we should actually check + + align:start position:0% +unsat, but we should actually check + + + align:start position:0% +unsat, but we should actually check +that. At this point, we've just + + align:start position:0% +that. At this point, we've just + + + align:start position:0% +that. At this point, we've just +simulated a circuit. We haven't thought + + align:start position:0% +simulated a circuit. We haven't thought + + + align:start position:0% +simulated a circuit. We haven't thought +about what we're trying to solve + + align:start position:0% +about what we're trying to solve + + + align:start position:0% +about what we're trying to solve +overall. Now we want to know whether we + + align:start position:0% +overall. Now we want to know whether we + + + align:start position:0% +overall. Now we want to know whether we +can derive everything. + + align:start position:0% +can derive everything. + + + align:start position:0% +can derive everything. +So we compute our formula and then the + + align:start position:0% +So we compute our formula and then the + + + align:start position:0% +So we compute our formula and then the +output is here and at this point there's + + align:start position:0% +output is here and at this point there's + + + align:start position:0% +output is here and at this point there's +just a terminal there saying I don't + + align:start position:0% +just a terminal there saying I don't + + + align:start position:0% +just a terminal there saying I don't +know what it is + + align:start position:0% +know what it is + + + align:start position:0% +know what it is +different from the previous proof right + + align:start position:0% +different from the previous proof right + + + align:start position:0% +different from the previous proof right +the previous proof said uh that should + + align:start position:0% +the previous proof said uh that should + + + align:start position:0% +the previous proof said uh that should +be one at the end and then you have to + + align:start position:0% +be one at the end and then you have to + + + align:start position:0% +be one at the end and then you have to +figure out how to fill in the things now + + align:start position:0% +figure out how to fill in the things now + + + align:start position:0% +figure out how to fill in the things now +we're saying I don't know what's there + + align:start position:0% +we're saying I don't know what's there + + + align:start position:0% +we're saying I don't know what's there +can you figure out what's there and if + + align:start position:0% +can you figure out what's there and if + + + align:start position:0% +can you figure out what's there and if +it's the case that no matter how you set + + align:start position:0% +it's the case that no matter how you set + + + align:start position:0% +it's the case that no matter how you set +the variables you always get false + + align:start position:0% +the variables you always get false + + + align:start position:0% +the variables you always get false +then you know uh what this wire looks + + align:start position:0% +then you know uh what this wire looks + + + align:start position:0% +then you know uh what this wire looks +like, you know that it's false. And in + + align:start position:0% +like, you know that it's false. And in + + + align:start position:0% +like, you know that it's false. And in +fact, you can figure out everything. If + + align:start position:0% +fact, you can figure out everything. If + + + align:start position:0% +fact, you can figure out everything. If +you know what all the x i are, you can + + align:start position:0% +you know what all the x i are, you can + + + align:start position:0% +you know what all the x i are, you can +just run through the circuit. Uh so you + + align:start position:0% +just run through the circuit. Uh so you + + + align:start position:0% +just run through the circuit. Uh so you +can figure out the entire diagram. But + + align:start position:0% +can figure out the entire diagram. But + + + align:start position:0% +can figure out the entire diagram. But +in general, just asking the question, + + align:start position:0% +in general, just asking the question, + + + align:start position:0% +in general, just asking the question, +can I figure out this square? Is there a + + align:start position:0% +can I figure out this square? Is there a + + + align:start position:0% +can I figure out this square? Is there a +bomb or not? In order for there not to + + align:start position:0% +bomb or not? In order for there not to + + + align:start position:0% +bomb or not? In order for there not to +be a bomb, uh you would have to solve + + align:start position:0% +be a bomb, uh you would have to solve + + + align:start position:0% +be a bomb, uh you would have to solve +this problem. uh you need to determine + + align:start position:0% +this problem. uh you need to determine + + + align:start position:0% +this problem. uh you need to determine +that no matter how you set the things + + align:start position:0% +that no matter how you set the things + + + align:start position:0% +that no matter how you set the things +you end up with a zero or the adjacent + + align:start position:0% +you end up with a zero or the adjacent + + + align:start position:0% +you end up with a zero or the adjacent +position it would be the opposite. Okay. + + align:start position:0% +position it would be the opposite. Okay. + + + align:start position:0% +position it would be the opposite. Okay. +So conversely what I really care about + + align:start position:0% +So conversely what I really care about + + + align:start position:0% +So conversely what I really care about +that was the wrong direction. I want I'm + + align:start position:0% +that was the wrong direction. I want I'm + + + align:start position:0% +that was the wrong direction. I want I'm +given a circuit unsat instance. I want + + align:start position:0% +given a circuit unsat instance. I want + + + align:start position:0% +given a circuit unsat instance. I want +to turn it into a mind sweeper instance. + + align:start position:0% +to turn it into a mind sweeper instance. + + + align:start position:0% +to turn it into a mind sweeper instance. +So I do that and then the the the + + align:start position:0% +So I do that and then the the the + + + align:start position:0% +So I do that and then the the the +question is you know uh get this right. + + align:start position:0% +question is you know uh get this right. + + + align:start position:0% +question is you know uh get this right. +Can you derive whether there is a bomb + + align:start position:0% +Can you derive whether there is a bomb + + + align:start position:0% +Can you derive whether there is a bomb +in this square? Can you determine that + + align:start position:0% +in this square? Can you determine that + + + align:start position:0% +in this square? Can you determine that +there uh must be a bomb in this square + + align:start position:0% +there uh must be a bomb in this square + + + align:start position:0% +there uh must be a bomb in this square +for example? That would be a slightly + + align:start position:0% +for example? That would be a slightly + + + align:start position:0% +for example? That would be a slightly +cleaner version. + + align:start position:0% +cleaner version. + + + align:start position:0% +cleaner version. +And that will be true if and only if no + + align:start position:0% +And that will be true if and only if no + + + align:start position:0% +And that will be true if and only if no +matter what you do there's a bomb in + + align:start position:0% +matter what you do there's a bomb in + + + align:start position:0% +matter what you do there's a bomb in +that square which is like saying no + + align:start position:0% +that square which is like saying no + + + align:start position:0% +that square which is like saying no +matter what you do uh this formula comes + + align:start position:0% +matter what you do uh this formula comes + + + align:start position:0% +matter what you do uh this formula comes +out to zero. Okay. So any kind of + + align:start position:0% +out to zero. Okay. So any kind of + + + align:start position:0% +out to zero. Okay. So any kind of +inference question like that is going to + + align:start position:0% +inference question like that is going to + + + align:start position:0% +inference question like that is going to +require you uh to solve this problem + + align:start position:0% +require you uh to solve this problem + + + align:start position:0% +require you uh to solve this problem +or rather this problem can be reduced to + + align:start position:0% +or rather this problem can be reduced to + + + align:start position:0% +or rather this problem can be reduced to +any inference problem like that. Clear? + + align:start position:0% +any inference problem like that. Clear? + + + align:start position:0% +any inference problem like that. Clear? +It's easy to get backwards here. So hope + + align:start position:0% +It's easy to get backwards here. So hope + + + align:start position:0% +It's easy to get backwards here. So hope +I got it all right. Uh and that's co-enp + + align:start position:0% +I got it all right. Uh and that's co-enp + + + align:start position:0% +I got it all right. Uh and that's co-enp +completeness. Reductions look the same + + align:start position:0% +completeness. Reductions look the same + + + align:start position:0% +completeness. Reductions look the same +for co-enp uh we just start with + + align:start position:0% +for co-enp uh we just start with + + + align:start position:0% +for co-enp uh we just start with +different problems. + + align:start position:0% + + + + align:start position:0% + +Cool. So that was mind sweeper + + align:start position:0% +Cool. So that was mind sweeper + + + align:start position:0% +Cool. So that was mind sweeper +uh and functional completeness. I have + + align:start position:0% +uh and functional completeness. I have + + + align:start position:0% +uh and functional completeness. I have +one more well sort of two more proofs + + align:start position:0% +one more well sort of two more proofs + + + align:start position:0% +one more well sort of two more proofs +only one that I will talk about in + + align:start position:0% +only one that I will talk about in + + + align:start position:0% +only one that I will talk about in +detail uh for Candy Crush and soon + + align:start position:0% +detail uh for Candy Crush and soon + + + align:start position:0% +detail uh for Candy Crush and soon +enough bejeweled. Um so but let's let's + + align:start position:0% +enough bejeweled. Um so but let's let's + + + align:start position:0% +enough bejeweled. Um so but let's let's +think about Candy Crush. This is the + + align:start position:0% +think about Candy Crush. This is the + + + align:start position:0% +think about Candy Crush. This is the +modern version. I'm guessing you've all + + align:start position:0% +modern version. I'm guessing you've all + + + align:start position:0% +modern version. I'm guessing you've all +played but in case not uh please don't + + align:start position:0% +played but in case not uh please don't + + + align:start position:0% +played but in case not uh please don't +play. It's very addictive. + + align:start position:0% +play. It's very addictive. + + + align:start position:0% +play. It's very addictive. +But on the slides, we're allowed to. So, + + align:start position:0% +But on the slides, we're allowed to. So, + + + align:start position:0% +But on the slides, we're allowed to. So, +um, you have a grid of colors, + + align:start position:0% +um, you have a grid of colors, + + + align:start position:0% +um, you have a grid of colors, +colored candies, and a move in this game + + align:start position:0% +colored candies, and a move in this game + + + align:start position:0% +colored candies, and a move in this game +is to take two candies and switch their + + align:start position:0% +is to take two candies and switch their + + + align:start position:0% +is to take two candies and switch their +order. Uh, I guess in this picture, I + + align:start position:0% +order. Uh, I guess in this picture, I + + + align:start position:0% +order. Uh, I guess in this picture, I +did these two. Okay, if you switch these + + align:start position:0% +did these two. Okay, if you switch these + + + align:start position:0% +did these two. Okay, if you switch these +two, you get this picture. And whenever + + align:start position:0% +two, you get this picture. And whenever + + + align:start position:0% +two, you get this picture. And whenever +and the the mechanics of the game, the + + align:start position:0% +and the the mechanics of the game, the + + + align:start position:0% +and the the mechanics of the game, the +physics or whatever is whenever you have + + align:start position:0% +physics or whatever is whenever you have + + + align:start position:0% +physics or whatever is whenever you have +three or more candies of the same color + + align:start position:0% +three or more candies of the same color + + + align:start position:0% +three or more candies of the same color +in a row or column, right in a row, uh + + align:start position:0% +in a row or column, right in a row, uh + + + align:start position:0% +in a row or column, right in a row, uh +then they disappear and anything above + + align:start position:0% +then they disappear and anything above + + + align:start position:0% +then they disappear and anything above +them falls. So like this red candy ends + + align:start position:0% +them falls. So like this red candy ends + + + align:start position:0% +them falls. So like this red candy ends +up there. In this case, there were no + + align:start position:0% +up there. In this case, there were no + + + align:start position:0% +up there. In this case, there were no +more candies above in the real game. + + align:start position:0% +more candies above in the real game. + + + align:start position:0% +more candies above in the real game. +Usually there's always more candies + + align:start position:0% +Usually there's always more candies + + + align:start position:0% +Usually there's always more candies +above. But if we're in a small game, uh + + align:start position:0% +above. But if we're in a small game, uh + + + align:start position:0% +above. But if we're in a small game, uh +this will if we're in a big game and + + align:start position:0% +this will if we're in a big game and + + + align:start position:0% +this will if we're in a big game and +looking at a small window, uh we know + + align:start position:0% +looking at a small window, uh we know + + + align:start position:0% +looking at a small window, uh we know +everything about what will fall. Do you + + align:start position:0% +everything about what will fall. Do you + + + align:start position:0% +everything about what will fall. Do you +need to move make them fall or do they + + align:start position:0% +need to move make them fall or do they + + + align:start position:0% +need to move make them fall or do they +automatically fall once you get + + align:start position:0% +automatically fall once you get + + + align:start position:0% +automatically fall once you get +they automatically fall? Yeah. So they + + align:start position:0% +they automatically fall? Yeah. So they + + + align:start position:0% +they automatically fall? Yeah. So they +they're forced to fall. + + align:start position:0% +they're forced to fall. + + + align:start position:0% +they're forced to fall. +Uh it's all I get to do is make this + + align:start position:0% +Uh it's all I get to do is make this + + + align:start position:0% +Uh it's all I get to do is make this +move and then stuff happens. So I make + + align:start position:0% +move and then stuff happens. So I make + + + align:start position:0% +move and then stuff happens. So I make +this move and then anything that uh any + + align:start position:0% +this move and then anything that uh any + + + align:start position:0% +this move and then anything that uh any +three in a rows or more disappear and + + align:start position:0% +three in a rows or more disappear and + + + align:start position:0% +three in a rows or more disappear and +then if that makes more three in a rows + + align:start position:0% +then if that makes more three in a rows + + + align:start position:0% +then if that makes more three in a rows +they will disappear and so on and I'm my + + align:start position:0% +they will disappear and so on and I'm my + + + align:start position:0% +they will disappear and so on and I'm my +hands are off at that point. Once that's + + align:start position:0% +hands are off at that point. Once that's + + + align:start position:0% +hands are off at that point. Once that's +once the chain reactions are finished. + + align:start position:0% +once the chain reactions are finished. + + + align:start position:0% +once the chain reactions are finished. +Not all games work this way but Candy + + align:start position:0% +Not all games work this way but Candy + + + align:start position:0% +Not all games work this way but Candy +Crush happens to work this way. Once + + align:start position:0% +Crush happens to work this way. Once + + + align:start position:0% +Crush happens to work this way. Once +these things are finished, then I can do + + align:start position:0% +these things are finished, then I can do + + + align:start position:0% +these things are finished, then I can do +another exchange. And when I do an + + align:start position:0% +another exchange. And when I do an + + + align:start position:0% +another exchange. And when I do an +exchange, I must make three in a row. I + + align:start position:0% +exchange, I must make three in a row. I + + + align:start position:0% +exchange, I must make three in a row. I +can't just swap these two guys because + + align:start position:0% +can't just swap these two guys because + + + align:start position:0% +can't just swap these two guys because +uh it's not interesting. + + align:start position:0% +uh it's not interesting. + + + align:start position:0% +uh it's not interesting. +Yeah. + + align:start position:0% +Yeah. + + + align:start position:0% +Yeah. +What if it's like a T pattern or like + + align:start position:0% +What if it's like a T pattern or like + + + align:start position:0% +What if it's like a T pattern or like +nonlinear? + + align:start position:0% +nonlinear? + + + align:start position:0% +nonlinear? +Uh in this uh T Yeah. Okay. In this + + align:start position:0% +Uh in this uh T Yeah. Okay. In this + + + align:start position:0% +Uh in this uh T Yeah. Okay. In this +picture, we'll never have T's. It'll + + align:start position:0% +picture, we'll never have T's. It'll + + + align:start position:0% +picture, we'll never have T's. It'll +always be three in a row. We'll never + + align:start position:0% +always be three in a row. We'll never + + + align:start position:0% +always be three in a row. We'll never +have four in a row. With four in a row, + + align:start position:0% +have four in a row. With four in a row, + + + align:start position:0% +have four in a row. With four in a row, +magical striped candies happen, and you + + align:start position:0% +magical striped candies happen, and you + + + align:start position:0% +magical striped candies happen, and you +don't want to know. + + align:start position:0% +don't want to know. + + + align:start position:0% +don't want to know. +So, uh, potentially you could get up to + + align:start position:0% +So, uh, potentially you could get up to + + + align:start position:0% +So, uh, potentially you could get up to +five in a row with these rules, but that + + align:start position:0% +five in a row with these rules, but that + + + align:start position:0% +five in a row with these rules, but that +that that in these reductions that won't + + align:start position:0% +that that in these reductions that won't + + + align:start position:0% +that that in these reductions that won't +happen. So, we don't care what the rules + + align:start position:0% +happen. So, we don't care what the rules + + + align:start position:0% +happen. So, we don't care what the rules +say there. Um, we're only going to get + + align:start position:0% +say there. Um, we're only going to get + + + align:start position:0% +say there. Um, we're only going to get +three in a rows. There is a weird catch + + align:start position:0% +three in a rows. There is a weird catch + + + align:start position:0% +three in a rows. There is a weird catch +in this proof. These I'm going to cover + + align:start position:0% +in this proof. These I'm going to cover + + + align:start position:0% +in this proof. These I'm going to cover +two mentioned two proofs from 2014. So, + + align:start position:0% +two mentioned two proofs from 2014. So, + + + align:start position:0% +two mentioned two proofs from 2014. So, +all very recent. I guess the game isn't + + align:start position:0% +all very recent. I guess the game isn't + + + align:start position:0% +all very recent. I guess the game isn't +that old. Um, and in this proof, we're + + align:start position:0% +that old. Um, and in this proof, we're + + + align:start position:0% +that old. Um, and in this proof, we're +going to assume if there are in general, + + align:start position:0% +going to assume if there are in general, + + + align:start position:0% +going to assume if there are in general, +there may be multiple three in a rows at + + align:start position:0% +there may be multiple three in a rows at + + + align:start position:0% +there may be multiple three in a rows at +once. And the proof is going to assume + + align:start position:0% +once. And the proof is going to assume + + + align:start position:0% +once. And the proof is going to assume +that they are resolved bottom to top. So + + align:start position:0% +that they are resolved bottom to top. So + + + align:start position:0% +that they are resolved bottom to top. So +you do the bottommost one first, + + align:start position:0% +you do the bottommost one first, + + + align:start position:0% +you do the bottommost one first, +things fall, then you do the next one, + + align:start position:0% +things fall, then you do the next one, + + + align:start position:0% +things fall, then you do the next one, +things fall. Do the next one, things + + align:start position:0% +things fall. Do the next one, things + + + align:start position:0% +things fall. Do the next one, things +fall. That's not how the actual game + + align:start position:0% +fall. That's not how the actual game + + + align:start position:0% +fall. That's not how the actual game +works. The game in the game, they all uh + + align:start position:0% +works. The game in the game, they all uh + + + align:start position:0% +works. The game in the game, they all uh +disappear simultaneously + + align:start position:0% +disappear simultaneously + + + align:start position:0% +disappear simultaneously +and then stuff falls. Okay, but ignore + + align:start position:0% +and then stuff falls. Okay, but ignore + + + align:start position:0% +and then stuff falls. Okay, but ignore +that for the moment. The next proof will + + align:start position:0% +that for the moment. The next proof will + + + align:start position:0% +that for the moment. The next proof will +change the model. Okay, this is a much + + align:start position:0% +change the model. Okay, this is a much + + + align:start position:0% +change the model. Okay, this is a much +easier one to think about and draw the + + align:start position:0% +easier one to think about and draw the + + + align:start position:0% +easier one to think about and draw the +pictures. So uh in that model, here's a + + align:start position:0% +pictures. So uh in that model, here's a + + + align:start position:0% +pictures. So uh in that model, here's a +variable gadget. We have uh this is the + + align:start position:0% +variable gadget. We have uh this is the + + + align:start position:0% +variable gadget. We have uh this is the +starting point. It's the same picture + + align:start position:0% +starting point. It's the same picture + + + align:start position:0% +starting point. It's the same picture +top and bottom. And the idea is either + + align:start position:0% +top and bottom. And the idea is either + + + align:start position:0% +top and bottom. And the idea is either +you exchange these two to make three or + + align:start position:0% +you exchange these two to make three or + + + align:start position:0% +you exchange these two to make three or +you exchange these two to make three. + + align:start position:0% +you exchange these two to make three. + + + align:start position:0% +you exchange these two to make three. +And the consequence is either the right + + align:start position:0% +And the consequence is either the right + + + align:start position:0% +And the consequence is either the right +column falls by three or the middle + + align:start position:0% +column falls by three or the middle + + + align:start position:0% +column falls by three or the middle +column falls by three. And that's all + + align:start position:0% +column falls by three. And that's all + + + align:start position:0% +column falls by three. And that's all +you can do local to this gadget. So + + align:start position:0% +you can do local to this gadget. So + + + align:start position:0% +you can do local to this gadget. So +that's easy. Things are going to get + + align:start position:0% +that's easy. Things are going to get + + + align:start position:0% +that's easy. Things are going to get +messier but um + + align:start position:0% +messier but um + + + align:start position:0% +messier but um +okay. So imag you have this picture + + align:start position:0% +okay. So imag you have this picture + + + align:start position:0% +okay. So imag you have this picture +variable gadget for XI. above it. I'm + + align:start position:0% +variable gadget for XI. above it. I'm + + + align:start position:0% +variable gadget for XI. above it. I'm +going to make one of these two gadgets. + + align:start position:0% +going to make one of these two gadgets. + + + align:start position:0% +going to make one of these two gadgets. +Actually, both of them, but one at a + + align:start position:0% +Actually, both of them, but one at a + + + align:start position:0% +Actually, both of them, but one at a +time. So, in fact, it will actually look + + align:start position:0% +time. So, in fact, it will actually look + + + align:start position:0% +time. So, in fact, it will actually look +kind of like this stacked on top of the + + align:start position:0% +kind of like this stacked on top of the + + + align:start position:0% +kind of like this stacked on top of the +variable, which is down here. So, + + align:start position:0% +variable, which is down here. So, + + + align:start position:0% +variable, which is down here. So, +variables down here. Either the uh + + align:start position:0% +variables down here. Either the uh + + + align:start position:0% +variables down here. Either the uh +center column falls or the right column + + align:start position:0% +center column falls or the right column + + + align:start position:0% +center column falls or the right column +falls. Now, the idea is this is going to + + align:start position:0% +falls. Now, the idea is this is going to + + + align:start position:0% +falls. Now, the idea is this is going to +eventually connect to a clause. And this + + align:start position:0% +eventually connect to a clause. And this + + + align:start position:0% +eventually connect to a clause. And this +variable, I should say this is not from + + align:start position:0% +variable, I should say this is not from + + + align:start position:0% +variable, I should say this is not from +circuit. This is from three set. Regular + + align:start position:0% +circuit. This is from three set. Regular + + + align:start position:0% +circuit. This is from three set. Regular +old 3AT. So that variable appears in the + + align:start position:0% +old 3AT. So that variable appears in the + + + align:start position:0% +old 3AT. So that variable appears in the +clause either in positive form or + + align:start position:0% +clause either in positive form or + + + align:start position:0% +clause either in positive form or +negative form. Positive use this gadget. + + align:start position:0% +negative form. Positive use this gadget. + + + align:start position:0% +negative form. Positive use this gadget. +Negative use this gadget. So in the + + align:start position:0% +Negative use this gadget. So in the + + + align:start position:0% +Negative use this gadget. So in the +positive case if this falls by three we + + align:start position:0% +positive case if this falls by three we + + + align:start position:0% +positive case if this falls by three we +get this picture and then these + + align:start position:0% +get this picture and then these + + + align:start position:0% +get this picture and then these +disappear and so this guy falls one + + align:start position:0% +disappear and so this guy falls one + + + align:start position:0% +disappear and so this guy falls one +more. And the idea is that's going to + + align:start position:0% +more. And the idea is that's going to + + + align:start position:0% +more. And the idea is that's going to +trigger something off to the right. That + + align:start position:0% +trigger something off to the right. That + + + align:start position:0% +trigger something off to the right. That +will be next slide. Okay. Uh that will + + align:start position:0% +will be next slide. Okay. Uh that will + + + align:start position:0% +will be next slide. Okay. Uh that will +be the wire gadget. Uh if the center + + align:start position:0% +be the wire gadget. Uh if the center + + + align:start position:0% +be the wire gadget. Uh if the center +column fell by three, nothing would + + align:start position:0% +column fell by three, nothing would + + + align:start position:0% +column fell by three, nothing would +happen, right? the purples. I should + + align:start position:0% +happen, right? the purples. I should + + + align:start position:0% +happen, right? the purples. I should +mention uh how these gadgets are + + align:start position:0% +mention uh how these gadgets are + + + align:start position:0% +mention uh how these gadgets are +constructed. There's a a fourcolor sort + + align:start position:0% +constructed. There's a a fourcolor sort + + + align:start position:0% +constructed. There's a a fourcolor sort +of checkerboard pattern. Every in odd + + align:start position:0% +of checkerboard pattern. Every in odd + + + align:start position:0% +of checkerboard pattern. Every in odd +rows it's alternating orange, green, + + align:start position:0% +rows it's alternating orange, green, + + + align:start position:0% +rows it's alternating orange, green, +orange, green. In even rows, it's + + align:start position:0% +orange, green. In even rows, it's + + + align:start position:0% +orange, green. In even rows, it's +alternating red, yellow, red, yellow. + + align:start position:0% +alternating red, yellow, red, yellow. + + + align:start position:0% +alternating red, yellow, red, yellow. +And then in a few places, we're going to + + align:start position:0% +And then in a few places, we're going to + + + align:start position:0% +And then in a few places, we're going to +put the purple ones cuz purple's best. + + align:start position:0% +put the purple ones cuz purple's best. + + + align:start position:0% +put the purple ones cuz purple's best. +Uh and all the action is going to be in + + align:start position:0% +Uh and all the action is going to be in + + + align:start position:0% +Uh and all the action is going to be in +the purple candies. Okay, the these guys + + align:start position:0% +the purple candies. Okay, the these guys + + + align:start position:0% +the purple candies. Okay, the these guys +are just uh out there. And the real game + + align:start position:0% +are just uh out there. And the real game + + + align:start position:0% +are just uh out there. And the real game +has six colors. We're only using five of + + align:start position:0% +has six colors. We're only using five of + + + align:start position:0% +has six colors. We're only using five of +them. So cool. Uh these guys are just + + align:start position:0% +them. So cool. Uh these guys are just + + + align:start position:0% +them. So cool. Uh these guys are just +sort of filler to make sure nothing else + + align:start position:0% +sort of filler to make sure nothing else + + + align:start position:0% +sort of filler to make sure nothing else +happens. But still things fall + + align:start position:0% +happens. But still things fall + + + align:start position:0% +happens. But still things fall +vertically in a nice controlled way. + + align:start position:0% +vertically in a nice controlled way. + + + align:start position:0% +vertically in a nice controlled way. +Okay. So if you if these fall by three, + + align:start position:0% +Okay. So if you if these fall by three, + + + align:start position:0% +Okay. So if you if these fall by three, +the purples don't align. So nothing + + align:start position:0% +the purples don't align. So nothing + + + align:start position:0% +the purples don't align. So nothing +happens in this case. Uh if the center + + align:start position:0% +happens in this case. Uh if the center + + + align:start position:0% +happens in this case. Uh if the center +one falls by three, we get alignment and + + align:start position:0% +one falls by three, we get alignment and + + + align:start position:0% +one falls by three, we get alignment and +that falls by one. So great. Uh also + + align:start position:0% +that falls by one. So great. Uh also + + + align:start position:0% +that falls by one. So great. Uh also +note these gadgets stack + + align:start position:0% +note these gadgets stack + + + align:start position:0% +note these gadgets stack +somewhat nicely in that other than these + + align:start position:0% +somewhat nicely in that other than these + + + align:start position:0% +somewhat nicely in that other than these +this three gap uh in in reality more + + align:start position:0% +this three gap uh in in reality more + + + align:start position:0% +this three gap uh in in reality more +candies will fill in here. I drew it + + align:start position:0% +candies will fill in here. I drew it + + + align:start position:0% +candies will fill in here. I drew it +this way so you could see how much the + + align:start position:0% +this way so you could see how much the + + + align:start position:0% +this way so you could see how much the +columns actually fall. Remember this all + + align:start position:0% +columns actually fall. Remember this all + + + align:start position:0% +columns actually fall. Remember this all +sort of happens in one one move. So this + + align:start position:0% +sort of happens in one one move. So this + + + align:start position:0% +sort of happens in one one move. So this +falls, these clear, then this will clear + + align:start position:0% +falls, these clear, then this will clear + + + align:start position:0% +falls, these clear, then this will clear +and stuff happens. Uh it's annoying. So, + + align:start position:0% +and stuff happens. Uh it's annoying. So, + + + align:start position:0% +and stuff happens. Uh it's annoying. So, +so far everything's good because uh + + align:start position:0% +so far everything's good because uh + + + align:start position:0% +so far everything's good because uh +we've each of these is followed by one + + align:start position:0% +we've each of these is followed by one + + + align:start position:0% +we've each of these is followed by one +in addition to the original three. + + align:start position:0% +in addition to the original three. + + + align:start position:0% +in addition to the original three. +Uh but in this case, uh this follows by + + align:start position:0% +Uh but in this case, uh this follows by + + + align:start position:0% +Uh but in this case, uh this follows by +an extra one. I think you need to add an + + align:start position:0% +an extra one. I think you need to add an + + + align:start position:0% +an extra one. I think you need to add an +extra candy here. I'm a little unclear + + align:start position:0% +extra candy here. I'm a little unclear + + + align:start position:0% +extra candy here. I'm a little unclear +in the details of how to do that. It's + + align:start position:0% +in the details of how to do that. It's + + + align:start position:0% +in the details of how to do that. It's +mentioned in the paper, but without + + align:start position:0% +mentioned in the paper, but without + + + align:start position:0% +mentioned in the paper, but without +details. So, uh anyway, in the end, we + + align:start position:0% +details. So, uh anyway, in the end, we + + + align:start position:0% +details. So, uh anyway, in the end, we +will have uh a bunch of these stacked on + + align:start position:0% +will have uh a bunch of these stacked on + + + align:start position:0% +will have uh a bunch of these stacked on +top of each other. Each time the + + align:start position:0% +top of each other. Each time the + + + align:start position:0% +top of each other. Each time the +variable occurs in various clauses, + + align:start position:0% +variable occurs in various clauses, + + + align:start position:0% +variable occurs in various clauses, +we're going to have some positive and + + align:start position:0% +we're going to have some positive and + + + align:start position:0% +we're going to have some positive and +some negative ones. And we want the same + + align:start position:0% +some negative ones. And we want the same + + + align:start position:0% +some negative ones. And we want the same +variable trigger. Ah, that's right. Uh, + + align:start position:0% +variable trigger. Ah, that's right. Uh, + + + align:start position:0% +variable trigger. Ah, that's right. Uh, +there will be well, okay, no, I'm going + + align:start position:0% +there will be well, okay, no, I'm going + + + align:start position:0% +there will be well, okay, no, I'm going +to leave it like that. + + align:start position:0% +to leave it like that. + + + align:start position:0% +to leave it like that. +So, at this point, we have um a purple + + align:start position:0% +So, at this point, we have um a purple + + + align:start position:0% +So, at this point, we have um a purple +thing triggering something to the right. + + align:start position:0% +thing triggering something to the right. + + + align:start position:0% +thing triggering something to the right. +So, now I'm going to show you how that + + align:start position:0% +So, now I'm going to show you how that + + + align:start position:0% +So, now I'm going to show you how that +part works. This is the wire. So, the + + align:start position:0% +part works. This is the wire. So, the + + + align:start position:0% +part works. This is the wire. So, the +wire itself is like this. And the idea + + align:start position:0% +wire itself is like this. And the idea + + + align:start position:0% +wire itself is like this. And the idea +is that when there's a purple one here, + + align:start position:0% +is that when there's a purple one here, + + + align:start position:0% +is that when there's a purple one here, +chain reaction happens. And it happens + + align:start position:0% +chain reaction happens. And it happens + + + align:start position:0% +chain reaction happens. And it happens +in this way. As soon as there's a purple + + align:start position:0% +in this way. As soon as there's a purple + + + align:start position:0% +in this way. As soon as there's a purple +um candy here, this clears, which makes + + align:start position:0% +um candy here, this clears, which makes + + + align:start position:0% +um candy here, this clears, which makes +these two fall by one, which clears that + + align:start position:0% +these two fall by one, which clears that + + + align:start position:0% +these two fall by one, which clears that +which makes this fall by one and + + align:start position:0% +which makes this fall by one and + + + align:start position:0% +which makes this fall by one and +triggers the next thing. Okay, this one + + align:start position:0% +triggers the next thing. Okay, this one + + + align:start position:0% +triggers the next thing. Okay, this one +uh + + align:start position:0% +uh + + + align:start position:0% +uh +some stacking happens. Let's see. So + + align:start position:0% +some stacking happens. Let's see. So + + + align:start position:0% +some stacking happens. Let's see. So +overall, uh I think this one is actually + + align:start position:0% +overall, uh I think this one is actually + + + align:start position:0% +overall, uh I think this one is actually +better behaved. Uh this falls by one + + align:start position:0% +better behaved. Uh this falls by one + + + align:start position:0% +better behaved. Uh this falls by one +here and then two. So overall these + + align:start position:0% +here and then two. So overall these + + + align:start position:0% +here and then two. So overall these +columns fell by two. This column has + + align:start position:0% +columns fell by two. This column has + + + align:start position:0% +columns fell by two. This column has +fallen so far by one uh but it's about + + align:start position:0% +fallen so far by one uh but it's about + + + align:start position:0% +fallen so far by one uh but it's about +to fall by a second one because this + + align:start position:0% +to fall by a second one because this + + + align:start position:0% +to fall by a second one because this +will always trigger something. And so + + align:start position:0% +will always trigger something. And so + + + align:start position:0% +will always trigger something. And so +these do stack nicely because you always + + align:start position:0% +these do stack nicely because you always + + + align:start position:0% +these do stack nicely because you always +clear exactly two columns. So the worry + + align:start position:0% +clear exactly two columns. So the worry + + + align:start position:0% +clear exactly two columns. So the worry +is that the gadget above it uh will be + + align:start position:0% +is that the gadget above it uh will be + + + align:start position:0% +is that the gadget above it uh will be +skewed. + + align:start position:0% +skewed. + + + align:start position:0% +skewed. +Okay. Uh + + align:start position:0% +Okay. Uh + + + align:start position:0% +Okay. Uh +let me give you one more gadget then + + align:start position:0% +let me give you one more gadget then + + + align:start position:0% +let me give you one more gadget then +I'll tell you how um no actually I think + + align:start position:0% +I'll tell you how um no actually I think + + + align:start position:0% +I'll tell you how um no actually I think +at this point I should tell you how + + align:start position:0% +at this point I should tell you how + + + align:start position:0% +at this point I should tell you how +things fit together + + align:start position:0% +things fit together + + + align:start position:0% +things fit together +which is + + align:start position:0% +which is + + + align:start position:0% +which is +this picture. + + align:start position:0% + + + + align:start position:0% + +Okay, so we have + + align:start position:0% +Okay, so we have + + + align:start position:0% +Okay, so we have +variables + + align:start position:0% +variables + + + align:start position:0% +variables +down here in the lower left. + + align:start position:0% + + + + align:start position:0% + +Then uh let's worry about one thing at a + + align:start position:0% +Then uh let's worry about one thing at a + + + align:start position:0% +Then uh let's worry about one thing at a +time. + + align:start position:0% + + + + align:start position:0% + +These are the uh connection gadgets. + + align:start position:0% + + + + align:start position:0% + +I didn't I don't think I told you their + + align:start position:0% +I didn't I don't think I told you their + + + align:start position:0% +I didn't I don't think I told you their +name, but they're your connector + + align:start position:0% +name, but they're your connector + + + align:start position:0% +name, but they're your connector +gadgets. This is sort of making a 90° + + align:start position:0% +gadgets. This is sort of making a 90° + + + align:start position:0% +gadgets. This is sort of making a 90° +turn. From the falling action, we're + + align:start position:0% +turn. From the falling action, we're + + + align:start position:0% +turn. From the falling action, we're +going to get a purple in a particular + + align:start position:0% +going to get a purple in a particular + + + align:start position:0% +going to get a purple in a particular +position, which causes rightward motion. + + align:start position:0% +position, which causes rightward motion. + + + align:start position:0% +position, which causes rightward motion. +And then, uh, the wires, as you saw, + + align:start position:0% +And then, uh, the wires, as you saw, + + + align:start position:0% +And then, uh, the wires, as you saw, +basically go in some angle off to the + + align:start position:0% +basically go in some angle off to the + + + align:start position:0% +basically go in some angle off to the +right. + + align:start position:0% + + + + align:start position:0% + +I want these all to be non-intersecting. + + align:start position:0% +I want these all to be non-intersecting. + + + align:start position:0% +I want these all to be non-intersecting. +Uh, + + align:start position:0% +Uh, + + + align:start position:0% +Uh, +and + + align:start position:0% +and + + + align:start position:0% +and +there's sort of two of them. There's + + align:start position:0% +there's sort of two of them. There's + + + align:start position:0% +there's sort of two of them. There's +going to be the true case and the false + + align:start position:0% +going to be the true case and the false + + + align:start position:0% +going to be the true case and the false +case. + + align:start position:0% +case. + + + align:start position:0% +case. +Okay? And then way over here somewhere, + + align:start position:0% +Okay? And then way over here somewhere, + + + align:start position:0% +Okay? And then way over here somewhere, +we're going to have clause + + align:start position:0% + + + + align:start position:0% + +where these wires all attach. And then + + align:start position:0% +where these wires all attach. And then + + + align:start position:0% +where these wires all attach. And then +above it, we're going to have a reward + + align:start position:0% +above it, we're going to have a reward + + + align:start position:0% +above it, we're going to have a reward +where you get tons of points and uh etc. + + align:start position:0% +where you get tons of points and uh etc. + + + align:start position:0% +where you get tons of points and uh etc. +So, + + align:start position:0% +So, + + + align:start position:0% +So, +let me tell you what happens next. Uh + + align:start position:0% +let me tell you what happens next. Uh + + + align:start position:0% +let me tell you what happens next. Uh +this is a fun way to draw the picture. + + align:start position:0% +this is a fun way to draw the picture. + + + align:start position:0% +this is a fun way to draw the picture. +So, above these we'll have some other + + align:start position:0% +So, above these we'll have some other + + + align:start position:0% +So, above these we'll have some other +connections. + + align:start position:0% + + + + align:start position:0% + +I should not do it in the same pattern. + + align:start position:0% +I should not do it in the same pattern. + + + align:start position:0% +I should not do it in the same pattern. +I should not do it like that. Yeah, + + align:start position:0% +I should not do it like that. Yeah, + + + align:start position:0% +I should not do it like that. Yeah, +sure. Connection. + + align:start position:0% +sure. Connection. + + + align:start position:0% +sure. Connection. +Connection. + + align:start position:0% + + + + align:start position:0% + +Okay. Again, diagonal lines. + + align:start position:0% +Okay. Again, diagonal lines. + + + align:start position:0% +Okay. Again, diagonal lines. +Great. Not quite diagonal. They're at + + align:start position:0% +Great. Not quite diagonal. They're at + + + align:start position:0% +Great. Not quite diagonal. They're at +some angle. We have a clause. Everything + + align:start position:0% +some angle. We have a clause. Everything + + + align:start position:0% +some angle. We have a clause. Everything +connects up. Above the claws is a + + align:start position:0% +connects up. Above the claws is a + + + align:start position:0% +connects up. Above the claws is a +reward. + + align:start position:0% + + + + align:start position:0% + +Okay. And then I move the boards. + + align:start position:0% + + + + align:start position:0% + +And that's the picture. + + align:start position:0% +And that's the picture. + + + align:start position:0% +And that's the picture. +Okay. So, and just above the variables, + + align:start position:0% +Okay. So, and just above the variables, + + + align:start position:0% +Okay. So, and just above the variables, +we just keep adding more connections + + align:start position:0% +we just keep adding more connections + + + align:start position:0% +we just keep adding more connections +connected to some clauses. And in this + + align:start position:0% +connected to some clauses. And in this + + + align:start position:0% +connected to some clauses. And in this +way, and it's not just three variables, + + align:start position:0% +way, and it's not just three variables, + + + align:start position:0% +way, and it's not just three variables, +of course, we can have different uh + + align:start position:0% +of course, we can have different uh + + + align:start position:0% +of course, we can have different uh +there's n variables down here, and we + + align:start position:0% +there's n variables down here, and we + + + align:start position:0% +there's n variables down here, and we +use some three of them, and then connect + + align:start position:0% +use some three of them, and then connect + + + align:start position:0% +use some three of them, and then connect +that off to a clause, and they're all + + align:start position:0% +that off to a clause, and they're all + + + align:start position:0% +that off to a clause, and they're all +just stacked. Uh I happen to draw the + + align:start position:0% +just stacked. Uh I happen to draw the + + + align:start position:0% +just stacked. Uh I happen to draw the +clauses one on top of the other. That + + align:start position:0% +clauses one on top of the other. That + + + align:start position:0% +clauses one on top of the other. That +shouldn't happen. Uh so there's some + + align:start position:0% +shouldn't happen. Uh so there's some + + + align:start position:0% +shouldn't happen. Uh so there's some +extra space here. This is more over to + + align:start position:0% +extra space here. This is more over to + + + align:start position:0% +extra space here. This is more over to +the right. So that none of them will + + align:start position:0% +the right. So that none of them will + + + align:start position:0% +the right. So that none of them will +interact with each other. That's the + + align:start position:0% +interact with each other. That's the + + + align:start position:0% +interact with each other. That's the +goal. + + align:start position:0% + + + + align:start position:0% + +Except there are some issues like uh + + align:start position:0% +Except there are some issues like uh + + + align:start position:0% +Except there are some issues like uh +notice this wire gadget. Notice uh dual + + align:start position:0% +notice this wire gadget. Notice uh dual + + + align:start position:0% +notice this wire gadget. Notice uh dual +rail logic, right? Either this is active + + align:start position:0% +rail logic, right? Either this is active + + + align:start position:0% +rail logic, right? Either this is active +or this is active. And we hope that not + + align:start position:0% +or this is active. And we hope that not + + + align:start position:0% +or this is active. And we hope that not +both of them are active, although that + + align:start position:0% +both of them are active, although that + + + align:start position:0% +both of them are active, although that +can actually happen here. I'll get to + + align:start position:0% +can actually happen here. I'll get to + + + align:start position:0% +can actually happen here. I'll get to +that. Uh so uh when this activates, + + align:start position:0% +that. Uh so uh when this activates, + + + align:start position:0% +that. Uh so uh when this activates, +notice this might this goes on top of a + + align:start position:0% +notice this might this goes on top of a + + + align:start position:0% +notice this might this goes on top of a +variable gadget. Now wire by itself is + + align:start position:0% +variable gadget. Now wire by itself is + + + align:start position:0% +variable gadget. Now wire by itself is +kind of good. We've seen uh it removes + + align:start position:0% +kind of good. We've seen uh it removes + + + align:start position:0% +kind of good. We've seen uh it removes +two things from every spot. So uh things + + align:start position:0% +two things from every spot. So uh things + + + align:start position:0% +two things from every spot. So uh things +don't shift too much. + + align:start position:0% +don't shift too much. + + + align:start position:0% +don't shift too much. +And furthermore uh we know we hope that + + align:start position:0% +And furthermore uh we know we hope that + + + align:start position:0% +And furthermore uh we know we hope that +either this activates or this activates. + + align:start position:0% +either this activates or this activates. + + + align:start position:0% +either this activates or this activates. +So this will shift by a consistent + + align:start position:0% +So this will shift by a consistent + + + align:start position:0% +So this will shift by a consistent +amount in either case. + + align:start position:0% +amount in either case. + + + align:start position:0% +amount in either case. +But uh + + align:start position:0% +But uh + + + align:start position:0% +But uh +the wire may get messed up because the + + align:start position:0% +the wire may get messed up because the + + + align:start position:0% +the wire may get messed up because the +variable actually removes three things + + align:start position:0% +variable actually removes three things + + + align:start position:0% +variable actually removes three things +from one of the columns. So, we need a + + align:start position:0% +from one of the columns. So, we need a + + + align:start position:0% +from one of the columns. So, we need a +better wire gadget, which looks like + + align:start position:0% +better wire gadget, which looks like + + + align:start position:0% +better wire gadget, which looks like +uh this. This is a super wire gadget. + + align:start position:0% +uh this. This is a super wire gadget. + + + align:start position:0% +uh this. This is a super wire gadget. +It's really cool. It works no matter how + + align:start position:0% +It's really cool. It works no matter how + + + align:start position:0% +It's really cool. It works no matter how +you use it kind of. So, this is what it + + align:start position:0% +you use it kind of. So, this is what it + + + align:start position:0% +you use it kind of. So, this is what it +looks like in general. And this is + + align:start position:0% +looks like in general. And this is + + + align:start position:0% +looks like in general. And this is +regular use. So, this is as before. Uh + + align:start position:0% +regular use. So, this is as before. Uh + + + align:start position:0% +regular use. So, this is as before. Uh +if we trigger this, then this triggers + + align:start position:0% +if we trigger this, then this triggers + + + align:start position:0% +if we trigger this, then this triggers +and this guy falls by one just like + + align:start position:0% +and this guy falls by one just like + + + align:start position:0% +and this guy falls by one just like +before. But now also if there's a + + align:start position:0% +before. But now also if there's a + + + align:start position:0% +before. But now also if there's a +variable down here and this column falls + + align:start position:0% +variable down here and this column falls + + + align:start position:0% +variable down here and this column falls +by three or sorry if this column falls + + align:start position:0% +by three or sorry if this column falls + + + align:start position:0% +by three or sorry if this column falls +by three. So it's same picture but + + align:start position:0% +by three. So it's same picture but + + + align:start position:0% +by three. So it's same picture but +things fell by three still everything + + align:start position:0% +things fell by three still everything + + + align:start position:0% +things fell by three still everything +works out. Uh this these two fall it's a + + align:start position:0% +works out. Uh this these two fall it's a + + + align:start position:0% +works out. Uh this these two fall it's a +different uh these two fall but they + + align:start position:0% +different uh these two fall but they + + + align:start position:0% +different uh these two fall but they +meet a different dude but there were a + + align:start position:0% +meet a different dude but there were a + + + align:start position:0% +meet a different dude but there were a +bunch of guys to meet up with so it's + + align:start position:0% +bunch of guys to meet up with so it's + + + align:start position:0% +bunch of guys to meet up with so it's +fine. Uh and I clearly drew the output + + align:start position:0% +fine. Uh and I clearly drew the output + + + align:start position:0% +fine. Uh and I clearly drew the output +in the wrong place. Uh the output should + + align:start position:0% +in the wrong place. Uh the output should + + + align:start position:0% +in the wrong place. Uh the output should +be here I think. Yeah. So in in this + + align:start position:0% +be here I think. Yeah. So in in this + + + align:start position:0% +be here I think. Yeah. So in in this +picture the output was here also it + + align:start position:0% +picture the output was here also it + + + align:start position:0% +picture the output was here also it +shifted by one. In this picture the + + align:start position:0% +shifted by one. In this picture the + + + align:start position:0% +shifted by one. In this picture the +output is here not up there. Okay. So in + + align:start position:0% +output is here not up there. Okay. So in + + + align:start position:0% +output is here not up there. Okay. So in +both cases it triggers. And finally if + + align:start position:0% +both cases it triggers. And finally if + + + align:start position:0% +both cases it triggers. And finally if +the middle column fell by three before + + align:start position:0% +the middle column fell by three before + + + align:start position:0% +the middle column fell by three before +this gadget activated then uh this again + + align:start position:0% +this gadget activated then uh this again + + + align:start position:0% +this gadget activated then uh this again +triggers uh this time with this guy + + align:start position:0% +triggers uh this time with this guy + + + align:start position:0% +triggers uh this time with this guy +being different. Instead of this one + + align:start position:0% +being different. Instead of this one + + + align:start position:0% +being different. Instead of this one +matching this one's matching. Uh that + + align:start position:0% +matching this one's matching. Uh that + + + align:start position:0% +matching this one's matching. Uh that +still triggers these guys and this is + + align:start position:0% +still triggers these guys and this is + + + align:start position:0% +still triggers these guys and this is +still the output. Okay. So this is a + + align:start position:0% +still the output. Okay. So this is a + + + align:start position:0% +still the output. Okay. So this is a +different wire gadget that works in + + align:start position:0% +different wire gadget that works in + + + align:start position:0% +different wire gadget that works in +three different scenarios depending on + + align:start position:0% +three different scenarios depending on + + + align:start position:0% +three different scenarios depending on +what happened below it. So that's good + + align:start position:0% +what happened below it. So that's good + + + align:start position:0% +what happened below it. So that's good +news that lets us + + align:start position:0% +news that lets us + + + align:start position:0% +news that lets us +do this type of wire. In general, we're + + align:start position:0% +do this type of wire. In general, we're + + + align:start position:0% +do this type of wire. In general, we're +going to have a chain reaction all the + + align:start position:0% +going to have a chain reaction all the + + + align:start position:0% +going to have a chain reaction all the +way down here till we get to the claws + + align:start position:0% +way down here till we get to the claws + + + align:start position:0% +way down here till we get to the claws +uh from bottom to top. These will + + align:start position:0% +uh from bottom to top. These will + + + align:start position:0% +uh from bottom to top. These will +resolve and let me show you the claws. + + align:start position:0% +resolve and let me show you the claws. + + + align:start position:0% +resolve and let me show you the claws. +Uh I think details are a little bit + + align:start position:0% +Uh I think details are a little bit + + + align:start position:0% +Uh I think details are a little bit +messy. Um there's a little locking + + align:start position:0% +messy. Um there's a little locking + + + align:start position:0% +messy. Um there's a little locking +mechanism here, but uh basically the + + align:start position:0% +mechanism here, but uh basically the + + + align:start position:0% +mechanism here, but uh basically the +idea is all of the these things come in + + align:start position:0% +idea is all of the these things come in + + + align:start position:0% +idea is all of the these things come in +X1, X1 bar, X2, X2 bar, all of the half + + align:start position:0% +X1, X1 bar, X2, X2 bar, all of the half + + + align:start position:0% +X1, X1 bar, X2, X2 bar, all of the half +wires or semiwires. Um and so we we + + align:start position:0% +wires or semiwires. Um and so we we + + + align:start position:0% +wires or semiwires. Um and so we we +expect one of these to activate. + + align:start position:0% +expect one of these to activate. + + + align:start position:0% +expect one of these to activate. +Maybe you don't do that, but that would + + align:start position:0% +Maybe you don't do that, but that would + + + align:start position:0% +Maybe you don't do that, but that would +be weird + + align:start position:0% +be weird + + + align:start position:0% +be weird +and you won't end up satisfying the + + align:start position:0% +and you won't end up satisfying the + + + align:start position:0% +and you won't end up satisfying the +clause. So if this one activates uh then + + align:start position:0% +clause. So if this one activates uh then + + + align:start position:0% +clause. So if this one activates uh then +these align and you're happy. If in + + align:start position:0% +these align and you're happy. If in + + + align:start position:0% +these align and you're happy. If in +general if you can get this column to + + align:start position:0% +general if you can get this column to + + + align:start position:0% +general if you can get this column to +fall you're going to be happy because + + align:start position:0% +fall you're going to be happy because + + + align:start position:0% +fall you're going to be happy because +above this thing is this reward gadget. + + align:start position:0% +above this thing is this reward gadget. + + + align:start position:0% +above this thing is this reward gadget. +If this column falls by one you get a + + align:start position:0% +If this column falls by one you get a + + + align:start position:0% +If this column falls by one you get a +million points. Okay. And every clause + + align:start position:0% +million points. Okay. And every clause + + + align:start position:0% +million points. Okay. And every clause +has its own reward of a million points. + + align:start position:0% +has its own reward of a million points. + + + align:start position:0% +has its own reward of a million points. +So and million here is like n squared or + + align:start position:0% +So and million here is like n squared or + + + align:start position:0% +So and million here is like n squared or +something. Uh so you really want to get + + align:start position:0% +something. Uh so you really want to get + + + align:start position:0% +something. Uh so you really want to get +these and the only way to do it is to + + align:start position:0% +these and the only way to do it is to + + + align:start position:0% +these and the only way to do it is to +satisfy the clauses. The only way to get + + align:start position:0% +satisfy the clauses. The only way to get + + + align:start position:0% +satisfy the clauses. The only way to get +all the points is to satisfy all the + + align:start position:0% +all the points is to satisfy all the + + + align:start position:0% +all the points is to satisfy all the +clauses. Okay. Now, uh the goal in this + + align:start position:0% +clauses. Okay. Now, uh the goal in this + + + align:start position:0% +clauses. Okay. Now, uh the goal in this +game, I didn't mention is to maximize + + align:start position:0% +game, I didn't mention is to maximize + + + align:start position:0% +game, I didn't mention is to maximize +the number of points you can get uh for + + align:start position:0% +the number of points you can get uh for + + + align:start position:0% +the number of points you can get uh for +a given number of moves. Usually in uh + + align:start position:0% +a given number of moves. Usually in uh + + + align:start position:0% +a given number of moves. Usually in uh +Candy Crush, you have a limited number + + align:start position:0% +Candy Crush, you have a limited number + + + align:start position:0% +Candy Crush, you have a limited number +of moves. Okay? So, the idea is you're + + align:start position:0% +of moves. Okay? So, the idea is you're + + + align:start position:0% +of moves. Okay? So, the idea is you're +just going to have enough moves to set + + align:start position:0% +just going to have enough moves to set + + + align:start position:0% +just going to have enough moves to set +each of the variables, right? If you end + + align:start position:0% +each of the variables, right? If you end + + + align:start position:0% +each of the variables, right? If you end +up setting one of the wires directly, + + align:start position:0% +up setting one of the wires directly, + + + align:start position:0% +up setting one of the wires directly, +you can trigger any wire by doing a + + align:start position:0% +you can trigger any wire by doing a + + + align:start position:0% +you can trigger any wire by doing a +little flip. You can say, "Oh, trigger + + align:start position:0% +little flip. You can say, "Oh, trigger + + + align:start position:0% +little flip. You can say, "Oh, trigger +this one wire." But that will satisfy at + + align:start position:0% +this one wire." But that will satisfy at + + + align:start position:0% +this one wire." But that will satisfy at +most one clause. Whereas if you do it on + + align:start position:0% +most one clause. Whereas if you do it on + + + align:start position:0% +most one clause. Whereas if you do it on +a variable, you're going to satisfy a + + align:start position:0% +a variable, you're going to satisfy a + + + align:start position:0% +a variable, you're going to satisfy a +bunch of clauses and that's clearly + + align:start position:0% +bunch of clauses and that's clearly + + + align:start position:0% +bunch of clauses and that's clearly +better. Uh so that's a bit of a argument + + align:start position:0% +better. Uh so that's a bit of a argument + + + align:start position:0% +better. Uh so that's a bit of a argument +you need to make. Uh it doesn't help + + align:start position:0% +you need to make. Uh it doesn't help + + + align:start position:0% +you need to make. Uh it doesn't help +enough. You could even set this wire and + + align:start position:0% +enough. You could even set this wire and + + + align:start position:0% +enough. You could even set this wire and +this wire uh you know an x wire and an + + align:start position:0% +this wire uh you know an x wire and an + + + align:start position:0% +this wire uh you know an x wire and an +xar wire. But uh you can show the claim + + align:start position:0% +xar wire. But uh you can show the claim + + + align:start position:0% +xar wire. But uh you can show the claim +is that will never uh buy you more uh + + align:start position:0% +is that will never uh buy you more uh + + + align:start position:0% +is that will never uh buy you more uh +that will never buy you as much as + + align:start position:0% +that will never buy you as much as + + + align:start position:0% +that will never buy you as much as +setting an entire variable. we set uh + + align:start position:0% +setting an entire variable. we set uh + + + align:start position:0% +setting an entire variable. we set uh +and here's the reason why uh I drew this + + align:start position:0% +and here's the reason why uh I drew this + + + align:start position:0% +and here's the reason why uh I drew this +picture simply that say oh for every + + align:start position:0% +picture simply that say oh for every + + + align:start position:0% +picture simply that say oh for every +clause we're going to have this picture + + align:start position:0% +clause we're going to have this picture + + + align:start position:0% +clause we're going to have this picture +connected to some variables in fact + + align:start position:0% +connected to some variables in fact + + + align:start position:0% +connected to some variables in fact +every time you have a clause you make a + + align:start position:0% +every time you have a clause you make a + + + align:start position:0% +every time you have a clause you make a +million copies of the clause a million + + align:start position:0% +million copies of the clause a million + + + align:start position:0% +million copies of the clause a million +is like n uh so that it's really worth + + align:start position:0% +is like n uh so that it's really worth + + + align:start position:0% +is like n uh so that it's really worth +setting the var every variable appears + + align:start position:0% +setting the var every variable appears + + + align:start position:0% +setting the var every variable appears +in in millions of clauses so you really + + align:start position:0% +in in millions of clauses so you really + + + align:start position:0% +in in millions of clauses so you really +want to set the variables if you just + + align:start position:0% +want to set the variables if you just + + + align:start position:0% +want to set the variables if you just +satisfy one measly clause and get one + + align:start position:0% +satisfy one measly clause and get one + + + align:start position:0% +satisfy one measly clause and get one +measly million points it's not worth it + + align:start position:0% +measly million points it's not worth it + + + align:start position:0% +measly million points it's not worth it +but if you You can get a million times a + + align:start position:0% +but if you You can get a million times a + + + align:start position:0% +but if you You can get a million times a +million points. Whoa. Trillion points. + + align:start position:0% +million points. Whoa. Trillion points. + + + align:start position:0% +million points. Whoa. Trillion points. +Okay. So that's why you should only set + + align:start position:0% +Okay. So that's why you should only set + + + align:start position:0% +Okay. So that's why you should only set +variables, not set wires directly. + + align:start position:0% +variables, not set wires directly. + + + align:start position:0% +variables, not set wires directly. +Okay. + + align:start position:0% +Okay. + + + align:start position:0% +Okay. +Uh + + align:start position:0% +Uh + + + align:start position:0% +Uh +I think I have roughly covered this + + align:start position:0% +I think I have roughly covered this + + + align:start position:0% +I think I have roughly covered this +proof except I didn't go up the chain. + + align:start position:0% +proof except I didn't go up the chain. + + + align:start position:0% +proof except I didn't go up the chain. +Uh here setting X1 bar doesn't do much + + align:start position:0% +Uh here setting X1 bar doesn't do much + + + align:start position:0% +Uh here setting X1 bar doesn't do much +except + + align:start position:0% +except + + + align:start position:0% +except +setting one or the other of these ends + + align:start position:0% +setting one or the other of these ends + + + align:start position:0% +setting one or the other of these ends +up shifting all of these things by one + + align:start position:0% +up shifting all of these things by one + + + align:start position:0% +up shifting all of these things by one +which ends up clearing this which shifts + + align:start position:0% +which ends up clearing this which shifts + + + align:start position:0% +which ends up clearing this which shifts +all of these columns by one. And + + align:start position:0% +all of these columns by one. And + + + align:start position:0% +all of these columns by one. And +basically things look really spread out + + align:start position:0% +basically things look really spread out + + + align:start position:0% +basically things look really spread out +here but as you work your way up they're + + align:start position:0% +here but as you work your way up they're + + + align:start position:0% +here but as you work your way up they're +coming more and more into alignment. So + + align:start position:0% +coming more and more into alignment. So + + + align:start position:0% +coming more and more into alignment. So +the idea is as long as things resolve + + align:start position:0% +the idea is as long as things resolve + + + align:start position:0% +the idea is as long as things resolve +from bottom to top um you fir well it + + align:start position:0% +from bottom to top um you fir well it + + + align:start position:0% +from bottom to top um you fir well it +doesn't yeah + + align:start position:0% +doesn't yeah + + + align:start position:0% +doesn't yeah +uh yeah then first you figure out + + align:start position:0% +uh yeah then first you figure out + + + align:start position:0% +uh yeah then first you figure out +whether x1 satisfy the clause if it + + align:start position:0% +whether x1 satisfy the clause if it + + + align:start position:0% +whether x1 satisfy the clause if it +doesn't it sets things up for x2 and + + align:start position:0% +doesn't it sets things up for x2 and + + + align:start position:0% +doesn't it sets things up for x2 and +then maybe x2 satisfies the clause if it + + align:start position:0% +then maybe x2 satisfies the clause if it + + + align:start position:0% +then maybe x2 satisfies the clause if it +doesn't it sets things up for x3 here + + align:start position:0% +doesn't it sets things up for x3 here + + + align:start position:0% +doesn't it sets things up for x3 here +they're spread out even more but by the + + align:start position:0% +they're spread out even more but by the + + + align:start position:0% +they're spread out even more but by the +time you've done these things below uh + + align:start position:0% +time you've done these things below uh + + + align:start position:0% +time you've done these things below uh +that that thing will be ready + + align:start position:0% +that that thing will be ready + + + align:start position:0% +that that thing will be ready +okay so that was the first proof + + align:start position:0% +okay so that was the first proof + + + align:start position:0% +okay so that was the first proof +The second proof uh uh sorry before + + align:start position:0% +The second proof uh uh sorry before + + + align:start position:0% +The second proof uh uh sorry before +interlude uh Candy Crush is based on a + + align:start position:0% +interlude uh Candy Crush is based on a + + + align:start position:0% +interlude uh Candy Crush is based on a +variety of games. Um most famous is + + align:start position:0% +variety of games. Um most famous is + + + align:start position:0% +variety of games. Um most famous is +Bejeweled but there's a long history of + + align:start position:0% +Bejeweled but there's a long history of + + + align:start position:0% +Bejeweled but there's a long history of +even Tetris is in there but uh there's a + + align:start position:0% +even Tetris is in there but uh there's a + + + align:start position:0% +even Tetris is in there but uh there's a +long history of match three games and + + align:start position:0% +long history of match three games and + + + align:start position:0% +long history of match three games and +pretty much all of these are nplete. I + + align:start position:0% +pretty much all of these are nplete. I + + + align:start position:0% +pretty much all of these are nplete. I +don't know the details of all of them, + + align:start position:0% +don't know the details of all of them, + + + align:start position:0% +don't know the details of all of them, +but there's this paper uh by three + + align:start position:0% +but there's this paper uh by three + + + align:start position:0% +but there's this paper uh by three +authors a little bit later in the year + + align:start position:0% +authors a little bit later in the year + + + align:start position:0% +authors a little bit later in the year +uh that proves basically all of these + + align:start position:0% +uh that proves basically all of these + + + align:start position:0% +uh that proves basically all of these +games are emptying complete even when + + align:start position:0% +games are emptying complete even when + + + align:start position:0% +games are emptying complete even when +you're not given a move limit. So this + + align:start position:0% +you're not given a move limit. So this + + + align:start position:0% +you're not given a move limit. So this +is interesting in Bejeweled the goal is + + align:start position:0% +is interesting in Bejeweled the goal is + + + align:start position:0% +is interesting in Bejeweled the goal is +just to maximize your score. You don't + + align:start position:0% +just to maximize your score. You don't + + + align:start position:0% +just to maximize your score. You don't +necessarily have a limit on the number + + align:start position:0% +necessarily have a limit on the number + + + align:start position:0% +necessarily have a limit on the number +of moves unlike Candy Crush. Uh so or in + + align:start position:0% +of moves unlike Candy Crush. Uh so or in + + + align:start position:0% +of moves unlike Candy Crush. Uh so or in +also in some levels of Candy Crush it's + + align:start position:0% +also in some levels of Candy Crush it's + + + align:start position:0% +also in some levels of Candy Crush it's +like that. So uh here it was very + + align:start position:0% +like that. So uh here it was very + + + align:start position:0% +like that. So uh here it was very +crucial that we only had enough moves to + + align:start position:0% +crucial that we only had enough moves to + + + align:start position:0% +crucial that we only had enough moves to +trigger all the variables. We didn't + + align:start position:0% +trigger all the variables. We didn't + + + align:start position:0% +trigger all the variables. We didn't +want to be able to do other things. Um, + + align:start position:0% +want to be able to do other things. Um, + + + align:start position:0% +want to be able to do other things. Um, +so here's a different proof and I'm just + + align:start position:0% +so here's a different proof and I'm just + + + align:start position:0% +so here's a different proof and I'm just +going to give the highle picture. Uh, + + align:start position:0% +going to give the highle picture. Uh, + + + align:start position:0% +going to give the highle picture. Uh, +basically, uh, this is cool because even + + align:start position:0% +basically, uh, this is cool because even + + + align:start position:0% +basically, uh, this is cool because even +just figuring out whether you can get + + align:start position:0% +just figuring out whether you can get + + + align:start position:0% +just figuring out whether you can get +this one gem, this one, uh, candy is + + align:start position:0% +this one gem, this one, uh, candy is + + + align:start position:0% +this one gem, this one, uh, candy is +hard. Uh, in order to do so, you have to + + align:start position:0% +hard. Uh, in order to do so, you have to + + + align:start position:0% +hard. Uh, in order to do so, you have to +line up all of these things for each + + align:start position:0% +line up all of these things for each + + + align:start position:0% +line up all of these things for each +clause. + + align:start position:0% +clause. + + + align:start position:0% +clause. +And here it's a reduction from exactly + + align:start position:0% +And here it's a reduction from exactly + + + align:start position:0% +And here it's a reduction from exactly +one three set, one and three set. So + + align:start position:0% +one three set, one and three set. So + + + align:start position:0% +one three set, one and three set. So +only if exactly one of the variables + + align:start position:0% +only if exactly one of the variables + + + align:start position:0% +only if exactly one of the variables +gets set correctly does this shift to + + align:start position:0% +gets set correctly does this shift to + + + align:start position:0% +gets set correctly does this shift to +the right level. And only when all of + + align:start position:0% +the right level. And only when all of + + + align:start position:0% +the right level. And only when all of +these are shifted to the right level can + + align:start position:0% +these are shifted to the right level can + + + align:start position:0% +these are shifted to the right level can +you trigger this wire to go all the way + + align:start position:0% +you trigger this wire to go all the way + + + align:start position:0% +you trigger this wire to go all the way +here and get that guy. And it's the only + + align:start position:0% +here and get that guy. And it's the only + + + align:start position:0% +here and get that guy. And it's the only +way to get that guy. You can't do it + + align:start position:0% +way to get that guy. You can't do it + + + align:start position:0% +way to get that guy. You can't do it +directly. You can only be triggered from + + align:start position:0% +directly. You can only be triggered from + + + align:start position:0% +directly. You can only be triggered from +the left hand side. And there's also a + + align:start position:0% +the left hand side. And there's also a + + + align:start position:0% +the left hand side. And there's also a +sequencer over here which forces all of + + align:start position:0% +sequencer over here which forces all of + + + align:start position:0% +sequencer over here which forces all of +the variables to get set before this + + align:start position:0% +the variables to get set before this + + + align:start position:0% +the variables to get set before this +happens. Uh so it's a little tricky + + align:start position:0% +happens. Uh so it's a little tricky + + + align:start position:0% +happens. Uh so it's a little tricky +because you don't want to have to you + + align:start position:0% +because you don't want to have to you + + + align:start position:0% +because you don't want to have to you +don't want it to be you could set half + + align:start position:0% +don't want it to be you could set half + + + align:start position:0% +don't want it to be you could set half +of them and then trigger this and then + + align:start position:0% +of them and then trigger this and then + + + align:start position:0% +of them and then trigger this and then +things happen to align in a cheating + + align:start position:0% +things happen to align in a cheating + + + align:start position:0% +things happen to align in a cheating +way. The details are complicated, but + + align:start position:0% +way. The details are complicated, but + + + align:start position:0% +way. The details are complicated, but +they actually implemented their + + align:start position:0% +they actually implemented their + + + align:start position:0% +they actually implemented their +reduction. + + align:start position:0% +reduction. + + + align:start position:0% +reduction. +Uh, so this is it. Now there, as it says + + align:start position:0% +Uh, so this is it. Now there, as it says + + + align:start position:0% +Uh, so this is it. Now there, as it says +here, there are 4,000 rows above and + + align:start position:0% +here, there are 4,000 rows above and + + + align:start position:0% +here, there are 4,000 rows above and +2,000 rows below. So it's a large + + align:start position:0% +2,000 rows below. So it's a large + + + align:start position:0% +2,000 rows below. So it's a large +construction and this is for this + + align:start position:0% +construction and this is for this + + + align:start position:0% +construction and this is for this +formula. + + align:start position:0% + + + + align:start position:0% + +Um, I can clean it up a little bit. + + align:start position:0% +Um, I can clean it up a little bit. + + + align:start position:0% +Um, I can clean it up a little bit. +Remove the again there's a background + + align:start position:0% +Remove the again there's a background + + + align:start position:0% +Remove the again there's a background +checkerboard pattern here. So if I + + align:start position:0% +checkerboard pattern here. So if I + + + align:start position:0% +checkerboard pattern here. So if I +generate instance then uh things are a + + align:start position:0% +generate instance then uh things are a + + + align:start position:0% +generate instance then uh things are a +little bit cleaner and I think + + align:start position:0% +little bit cleaner and I think + + + align:start position:0% +little bit cleaner and I think +highlighted in red are the moves you can + + align:start position:0% +highlighted in red are the moves you can + + + align:start position:0% +highlighted in red are the moves you can +make. So here's the first variable. You + + align:start position:0% +make. So here's the first variable. You + + + align:start position:0% +make. So here's the first variable. You +can either uh let's do the simple one + + align:start position:0% +can either uh let's do the simple one + + + align:start position:0% +can either uh let's do the simple one +first. Move this guy with this one and + + align:start position:0% +first. Move this guy with this one and + + + align:start position:0% +first. Move this guy with this one and +then trigger trigger trigger. All this + + align:start position:0% +then trigger trigger trigger. All this + + + align:start position:0% +then trigger trigger trigger. All this +happens without you able to do anything. + + align:start position:0% +happens without you able to do anything. + + + align:start position:0% +happens without you able to do anything. +And that will move some stuff up top. Um + + align:start position:0% +And that will move some stuff up top. Um + + + align:start position:0% +And that will move some stuff up top. Um +or + + align:start position:0% +or + + + align:start position:0% +or +uh we can move this one here and then + + align:start position:0% +uh we can move this one here and then + + + align:start position:0% +uh we can move this one here and then +this is fun. The variable goes down and + + align:start position:0% +this is fun. The variable goes down and + + + align:start position:0% +this is fun. The variable goes down and +it just keeps it goes down basically to + + align:start position:0% +it just keeps it goes down basically to + + + align:start position:0% +it just keeps it goes down basically to +where the x1 bar is down here and then + + align:start position:0% +where the x1 bar is down here and then + + + align:start position:0% +where the x1 bar is down here and then +it triggers that guy and maybe that guy + + align:start position:0% +it triggers that guy and maybe that guy + + + align:start position:0% +it triggers that guy and maybe that guy +also. Okay. And that one and that one. + + align:start position:0% +also. Okay. And that one and that one. + + + align:start position:0% +also. Okay. And that one and that one. +Okay. Uh, lots of stuff happens. Anyway, + + align:start position:0% +Okay. Uh, lots of stuff happens. Anyway, + + + align:start position:0% +Okay. Uh, lots of stuff happens. Anyway, +eventually we'll get down to X2 and + + align:start position:0% +eventually we'll get down to X2 and + + + align:start position:0% +eventually we'll get down to X2 and +we'll be able to set it one way or the + + align:start position:0% +we'll be able to set it one way or the + + + align:start position:0% +we'll be able to set it one way or the +other. Uh, so the details are obviously + + align:start position:0% +other. Uh, so the details are obviously + + + align:start position:0% +other. Uh, so the details are obviously +a little bit complicated, but clearly + + align:start position:0% +a little bit complicated, but clearly + + + align:start position:0% +a little bit complicated, but clearly +they've been explicitly worked out + + align:start position:0% +they've been explicitly worked out + + + align:start position:0% +they've been explicitly worked out +because they can even play the game, + + align:start position:0% +because they can even play the game, + + + align:start position:0% +because they can even play the game, +which is pretty awesome. Uh, anyway, and + + align:start position:0% +which is pretty awesome. Uh, anyway, and + + + align:start position:0% +which is pretty awesome. Uh, anyway, and +they also have the greatest URL, uh, + + align:start position:0% +they also have the greatest URL, uh, + + + align:start position:0% +they also have the greatest URL, uh, +candycrush.ismpnard.com. + + align:start position:0% +candycrush.ismpnard.com. + + + align:start position:0% +candycrush.ismpnard.com. +We should try to get other + + align:start position:0% +We should try to get other + + + align:start position:0% +We should try to get other +things.ismpnard.com. + + align:start position:0% +things.ismpnard.com. + + + align:start position:0% +things.ismpnard.com. +Um, and that is Candy Crush and + + align:start position:0% +Um, and that is Candy Crush and + + + align:start position:0% +Um, and that is Candy Crush and +Bejeweled and all of its friends RNP + + align:start position:0% +Bejeweled and all of its friends RNP + + + align:start position:0% +Bejeweled and all of its friends RNP +hard. Uh, and I think that's it unless + + align:start position:0% +hard. Uh, and I think that's it unless + + + align:start position:0% +hard. Uh, and I think that's it unless +there are questions. + + align:start position:0% +there are questions. + + + align:start position:0% +there are questions. +Uh, so we've just started to scratch the + + align:start position:0% +Uh, so we've just started to scratch the + + + align:start position:0% +Uh, so we've just started to scratch the +surface on the idea that planer graphs + + align:start position:0% +surface on the idea that planer graphs + + + align:start position:0% +surface on the idea that planer graphs +are hard and next class we'll see planer + + align:start position:0% +are hard and next class we'll see planer + + + align:start position:0% +are hard and next class we'll see planer +versions of threes and one and three + + align:start position:0% +versions of threes and one and three + + + align:start position:0% +versions of threes and one and three +setat which we weren't using here. This + + align:start position:0% +setat which we weren't using here. This + + + align:start position:0% +setat which we weren't using here. This +is using a non-pler thing. Uh, so that + + align:start position:0% +is using a non-pler thing. Uh, so that + + + align:start position:0% +is using a non-pler thing. Uh, so that +will that helps with a lot of proofs + + align:start position:0% +will that helps with a lot of proofs + + + align:start position:0% +will that helps with a lot of proofs +especially ones that happen in the + + align:start position:0% +especially ones that happen in the + + + align:start position:0% +especially ones that happen in the +plane. + + align:start position:0% +plane. + + + align:start position:0% +plane. +Um so we've seen it with planer circuit + + align:start position:0% +Um so we've seen it with planer circuit + + + align:start position:0% +Um so we've seen it with planer circuit +set but next we'll do planer three set + + align:start position:0% +set but next we'll do planer three set + + + align:start position:0% +set but next we'll do planer three set +planer one and three setat planer not + + align:start position:0% +planer one and three setat planer not + + + align:start position:0% +planer one and three setat planer not +all equal sat those kinds of things and + + align:start position:0% +all equal sat those kinds of things and + + + align:start position:0% +all equal sat those kinds of things and +again be able to avoid crossovers which + + align:start position:0% +again be able to avoid crossovers which + + + align:start position:0% +again be able to avoid crossovers which +is nice. + + align:start position:0% +is nice. + + + align:start position:0% +is nice. +Cool. \ No newline at end of file diff --git a/zvu9SoCyDec.txt b/zvu9SoCyDec.txt new file mode 100644 index 0000000000000000000000000000000000000000..f01fc3156c059114119f83e6fcbf30110d85c1a8 --- /dev/null +++ b/zvu9SoCyDec.txt @@ -0,0 +1,7790 @@ +align:start position:0% + +okay we'll go through these together + + align:start position:0% +okay we'll go through these together + + + align:start position:0% +okay we'll go through these together +repeat after me civil civil civility + + align:start position:0% +repeat after me civil civil civility + + + align:start position:0% +repeat after me civil civil civility +civility civilized civilized + + align:start position:0% +civility civilized civilized + + + align:start position:0% +civility civilized civilized +civilization civilization equal equal + + align:start position:0% +civilization civilization equal equal + + + align:start position:0% +civilization civilization equal equal +equality equality equalize equalize + + align:start position:0% +equality equality equalize equalize + + + align:start position:0% +equality equality equalize equalize +Equalization Equalization fertile + + align:start position:0% +Equalization Equalization fertile + + + align:start position:0% +Equalization Equalization fertile +fertile fertility fertility fertilize + + align:start position:0% +fertile fertility fertility fertilize + + + align:start position:0% +fertile fertility fertility fertilize +fertilize fertilization fertilization + + align:start position:0% +fertilize fertilization fertilization + + + align:start position:0% +fertilize fertilization fertilization +final final finale + + align:start position:0% +final final finale + + + align:start position:0% +final final finale +finality finalize finalize finalization + + align:start position:0% +finality finalize finalize finalization + + + align:start position:0% +finality finalize finalize finalization +finalization General General generality + + align:start position:0% +finalization General General generality + + + align:start position:0% +finalization General General generality +generality generalize generalize + + align:start position:0% +generality generalize generalize + + + align:start position:0% +generality generalize generalize +generalization generalization hospital + + align:start position:0% +generalization generalization hospital + + + align:start position:0% +generalization generalization hospital +hospital Hospitality Hospitality + + align:start position:0% +hospital Hospitality Hospitality + + + align:start position:0% +hospital Hospitality Hospitality +hospitalized hospitalized + + align:start position:0% +hospitalized hospitalized + + + align:start position:0% +hospitalized hospitalized +hospitalization hospitalization legal + + align:start position:0% +hospitalization hospitalization legal + + + align:start position:0% +hospitalization hospitalization legal +legal legality legality legalize + + align:start position:0% +legal legality legality legalize + + + align:start position:0% +legal legality legality legalize +legalize legalization legalization + + align:start position:0% +legalize legalization legalization + + + align:start position:0% +legalize legalization legalization +mobile mobile Mobility Mobility mobilize + + align:start position:0% +mobile mobile Mobility Mobility mobilize + + + align:start position:0% +mobile mobile Mobility Mobility mobilize +mobilize mobilization mobilization + + align:start position:0% +mobilize mobilization mobilization + + + align:start position:0% +mobilize mobilization mobilization +National National nationality + + align:start position:0% +National National nationality + + + align:start position:0% +National National nationality +nationality nationalize nationalize + + align:start position:0% +nationality nationalize nationalize + + + align:start position:0% +nationality nationalize nationalize +nationalization nationalization neutral + + align:start position:0% +nationalization nationalization neutral + + + align:start position:0% +nationalization nationalization neutral +neutral neutrality neutrality NE + + align:start position:0% +neutral neutrality neutrality NE + + + align:start position:0% +neutral neutrality neutrality NE +neutralize neutralized neutralization + + align:start position:0% +neutralize neutralized neutralization + + + align:start position:0% +neutralize neutralized neutralization +neutralization personal personal + + align:start position:0% +neutralization personal personal + + + align:start position:0% +neutralization personal personal +personality personality personalize + + align:start position:0% +personality personality personalize + + + align:start position:0% +personality personality personalize +personalized personalization personaliz + + align:start position:0% +personalized personalization personaliz + + + align:start position:0% +personalized personalization personaliz +realation real real reality reality + + align:start position:0% +realation real real reality reality + + + align:start position:0% +realation real real reality reality +realize realize realization realization + + align:start position:0% +realize realize realization realization + + + align:start position:0% +realize realize realization realization +stable stable stability stability + + align:start position:0% +stable stable stability stability + + + align:start position:0% +stable stable stability stability +stabilize stabilize stabilization + + align:start position:0% +stabilize stabilize stabilization + + + align:start position:0% +stabilize stabilize stabilization +stabilization sterile sterile sterility + + align:start position:0% +stabilization sterile sterile sterility + + + align:start position:0% +stabilization sterile sterile sterility +sterility sterilize sterilize + + align:start position:0% +sterility sterilize sterilize + + + align:start position:0% +sterility sterilize sterilize +sterilization sterilization + + align:start position:0% +sterilization sterilization + + + align:start position:0% +sterilization sterilization +sterilization + + align:start position:0% +sterilization + + + align:start position:0% +sterilization +okay so we're going to go like this + + align:start position:0% +okay so we're going to go like this + + + align:start position:0% +okay so we're going to go like this +like this okay like this each person + + align:start position:0% +like this okay like this each person + + + align:start position:0% +like this okay like this each person +reads each one word starting with Geno + + align:start position:0% +reads each one word starting with Geno + + + align:start position:0% +reads each one word starting with Geno +loud as loudly as possible one word + + align:start position:0% +loud as loudly as possible one word + + + align:start position:0% +loud as loudly as possible one word +cability + + align:start position:0% + + + + align:start position:0% + +civilized civiliz civilized + + align:start position:0% +civilized civiliz civilized + + + align:start position:0% +civilized civiliz civilized +Cil civilized civiliz next civilization + + align:start position:0% +Cil civilized civiliz next civilization + + + align:start position:0% +Cil civilized civiliz next civilization +equal equality + + align:start position:0% +equal equality + + + align:start position:0% +equal equality +equalize Equalization + + align:start position:0% + + + + align:start position:0% + +F becomes a FL ferle ferle next + + align:start position:0% +F becomes a FL ferle ferle next + + + align:start position:0% +F becomes a FL ferle ferle next +fertility very good next F fer + + align:start position:0% +fertility very good next F fer + + + align:start position:0% +fertility very good next F fer +fation + + align:start position:0% +fation + + + align:start position:0% +fation +fation + + align:start position:0% +fation + + + align:start position:0% +fation +fer + + align:start position:0% +fer + + + align:start position:0% +fer +this is very difficult because you have + + align:start position:0% +this is very difficult because you have + + + align:start position:0% +this is very difficult because you have +the r and the flat fle + + align:start position:0% +the r and the flat fle + + + align:start position:0% +the r and the flat fle +ferle + + align:start position:0% +ferle + + + align:start position:0% +ferle +F + + align:start position:0% +F + + + align:start position:0% +F +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +I think uh fertile fertile I think + + align:start position:0% +I think uh fertile fertile I think + + + align:start position:0% +I think uh fertile fertile I think +that's uh British English fertile know + + align:start position:0% +that's uh British English fertile know + + + align:start position:0% +that's uh British English fertile know +but here in America we usually say + + align:start position:0% +but here in America we usually say + + + align:start position:0% +but here in America we usually say +fertile ferle + + align:start position:0% +fertile ferle + + + align:start position:0% +fertile ferle +next + + align:start position:0% + + + + align:start position:0% + +louder + + align:start position:0% +louder + + + align:start position:0% +louder +next + + align:start position:0% +next + + + align:start position:0% +next +okay + + align:start position:0% +okay + + + align:start position:0% +okay +next + + align:start position:0% +next + + + align:start position:0% +next +generality + + align:start position:0% + + + + align:start position:0% + +very good generaliz very good + + align:start position:0% +very good generaliz very good + + + align:start position:0% +very good generaliz very good +generalization + + align:start position:0% +generalization + + + align:start position:0% +generalization +huh + + align:start position:0% +huh + + + align:start position:0% +huh +generalization okay generalization + + align:start position:0% +generalization okay generalization + + + align:start position:0% +generalization okay generalization +generalization + + align:start position:0% +generalization + + + align:start position:0% +generalization +usually General love J and a j and a j + + align:start position:0% +usually General love J and a j and a j + + + align:start position:0% +usually General love J and a j and a j +and z generalization + + align:start position:0% +and z generalization + + + align:start position:0% +and z generalization +generalization + + align:start position:0% +generalization + + + align:start position:0% +generalization +next + + align:start position:0% +next + + + align:start position:0% +next +very good next Hospitality huh + + align:start position:0% +very good next Hospitality huh + + + align:start position:0% +very good next Hospitality huh +Hospitality + + align:start position:0% +Hospitality + + + align:start position:0% +Hospitality +hosp okay first one what's the first one + + align:start position:0% +hosp okay first one what's the first one + + + align:start position:0% +hosp okay first one what's the first one +hospital hospital becomes T becomes a + + align:start position:0% +hospital hospital becomes T becomes a + + + align:start position:0% +hospital hospital becomes T becomes a +flat right Hospital what happens to the + + align:start position:0% +flat right Hospital what happens to the + + + align:start position:0% +flat right Hospital what happens to the +next one + + align:start position:0% +next one + + + align:start position:0% +next one +Hospitality + + align:start position:0% +Hospitality + + + align:start position:0% +Hospitality +Hospitality why + + align:start position:0% +Hospitality why + + + align:start position:0% +Hospitality why +stress stress okay one more time + + align:start position:0% +stress stress okay one more time + + + align:start position:0% +stress stress okay one more time +Hospitality + + align:start position:0% + + + + align:start position:0% + +Hospitality Hospitality hospitality very + + align:start position:0% +Hospitality Hospitality hospitality very + + + align:start position:0% +Hospitality Hospitality hospitality very +good next uh starting with J again + + align:start position:0% +good next uh starting with J again + + + align:start position:0% +good next uh starting with J again +hospitalize + + align:start position:0% +hospitalize + + + align:start position:0% +hospitalize +hospitalize + + align:start position:0% +hospitalize + + + align:start position:0% +hospitalize +okay give us the flat hospitalize + + align:start position:0% +okay give us the flat hospitalize + + + align:start position:0% +okay give us the flat hospitalize +hospitalize hospitalize hospitalize next + + align:start position:0% +hospitalize hospitalize hospitalize next + + + align:start position:0% +hospitalize hospitalize hospitalize next +hospitalization + + align:start position:0% +hospitalization + + + align:start position:0% +hospitalization +Hospital okay next + + align:start position:0% +Hospital okay next + + + align:start position:0% +Hospital okay next +next legality + + align:start position:0% +next legality + + + align:start position:0% +next legality +legality leg use a legality or legal + + align:start position:0% +legality leg use a legality or legal + + + align:start position:0% +legality leg use a legality or legal +that's fine legality next legalize next + + align:start position:0% +that's fine legality next legalize next + + + align:start position:0% +that's fine legality next legalize next +I'm sorry legalization huh legalization + + align:start position:0% +I'm sorry legalization huh legalization + + + align:start position:0% +I'm sorry legalization huh legalization +very good next mobile perfect mobile + + align:start position:0% +very good next mobile perfect mobile + + + align:start position:0% +very good next mobile perfect mobile +okay mobile stress is a mo so it becomes + + align:start position:0% +okay mobile stress is a mo so it becomes + + + align:start position:0% +okay mobile stress is a mo so it becomes +M mile okay next Mobility perfect next + + align:start position:0% +M mile okay next Mobility perfect next + + + align:start position:0% +M mile okay next Mobility perfect next +mobilize perfect next mobilization good + + align:start position:0% +mobilize perfect next mobilization good + + + align:start position:0% +mobilize perfect next mobilization good +next national good next nationality + + align:start position:0% +next national good next nationality + + + align:start position:0% +next national good next nationality +huh nationality + + align:start position:0% +huh nationality + + + align:start position:0% +huh nationality +give us the flat + + align:start position:0% +give us the flat + + + align:start position:0% +give us the flat +nationality + + align:start position:0% +nationality + + + align:start position:0% +nationality +nationality + + align:start position:0% +nationality + + + align:start position:0% +nationality +a okay nationality next + + align:start position:0% +a okay nationality next + + + align:start position:0% +a okay nationality next +next + + align:start position:0% + + + + align:start position:0% + +next + + align:start position:0% +next + + + align:start position:0% +next +next + + align:start position:0% + + + + align:start position:0% + +what + + align:start position:0% +what + + + align:start position:0% +what +neutal neutrality neut t r TR R together + + align:start position:0% +neutal neutrality neut t r TR R together + + + align:start position:0% +neutal neutrality neut t r TR R together +TR R whenever you have TR together T + + align:start position:0% +TR R whenever you have TR together T + + + align:start position:0% +TR R whenever you have TR together T +sounds like what two like tree tree tree + + align:start position:0% +sounds like what two like tree tree tree + + + align:start position:0% +sounds like what two like tree tree tree +like church so ne ne liing neutrality + + align:start position:0% +like church so ne ne liing neutrality + + + align:start position:0% +like church so ne ne liing neutrality +many times Neal how many times Neal no + + align:start position:0% +many times Neal how many times Neal no + + + align:start position:0% +many times Neal how many times Neal no +no no + + align:start position:0% +no no + + + align:start position:0% +no no +h + + align:start position:0% + + + + align:start position:0% + +very good neutrality + + align:start position:0% +very good neutrality + + + align:start position:0% +very good neutrality +next + + align:start position:0% +next + + + align:start position:0% +next +next neutralization next personal next + + align:start position:0% +next neutralization next personal next + + + align:start position:0% +next neutralization next personal next +was the flap personality very good + + align:start position:0% +was the flap personality very good + + + align:start position:0% +was the flap personality very good +personality + + align:start position:0% +personality + + + align:start position:0% +personality +next personal next personalization next + + align:start position:0% +next personal next personalization next + + + align:start position:0% +next personal next personalization next +uh you know real next reality next + + align:start position:0% +uh you know real next reality next + + + align:start position:0% +uh you know real next reality next +real realize realize realize realize + + align:start position:0% +real realize realize realize realize + + + align:start position:0% +real realize realize realize realize +next realization next stable next + + align:start position:0% +next realization next stable next + + + align:start position:0% +next realization next stable next +stability stability stability + + align:start position:0% + + + + align:start position:0% + +stable + + align:start position:0% +stable + + + align:start position:0% +stable +stability stability stability + + align:start position:0% +stability stability stability + + + align:start position:0% +stability stability stability +stabilize huh stabilize + + align:start position:0% +stabilize huh stabilize + + + align:start position:0% +stabilize huh stabilize +stabilize + + align:start position:0% +stabilize + + + align:start position:0% +stabilize +St a a stabilize stabilize stabilize + + align:start position:0% +St a a stabilize stabilize stabilize + + + align:start position:0% +St a a stabilize stabilize stabilize +stabilize next stabil stabilization + + align:start position:0% +stabilize next stabil stabilization + + + align:start position:0% +stabilize next stabil stabilization +stabil stable stabilization + + align:start position:0% +stabil stable stabilization + + + align:start position:0% +stabil stable stabilization +stabilization stabilization + + align:start position:0% +stabilization stabilization + + + align:start position:0% +stabilization stabilization +okay next + + align:start position:0% + + + + align:start position:0% + +sterile + + align:start position:0% +sterile + + + align:start position:0% +sterile +F + + align:start position:0% +F + + + align:start position:0% +F +sterile ster okay next sterility very + + align:start position:0% +sterile ster okay next sterility very + + + align:start position:0% +sterile ster okay next sterility very +good give us the flap sterility very + + align:start position:0% +good give us the flap sterility very + + + align:start position:0% +good give us the flap sterility very +good + + align:start position:0% +good + + + align:start position:0% +good +one more time sterility sterility + + align:start position:0% +one more time sterility sterility + + + align:start position:0% +one more time sterility sterility +sterility St steril St sterility okay St + + align:start position:0% +sterility St steril St sterility okay St + + + align:start position:0% +sterility St steril St sterility okay St +plus all St St stay stay stable St + + align:start position:0% +plus all St St stay stay stable St + + + align:start position:0% +plus all St St stay stay stable St +stability + + align:start position:0% +stability + + + align:start position:0% +stability +stability next St huh St sterilize + + align:start position:0% +stability next St huh St sterilize + + + align:start position:0% +stability next St huh St sterilize +steril next + + align:start position:0% + + + + align:start position:0% + +sterilization + + align:start position:0% +sterilization + + + align:start position:0% +sterilization +any questions what's the pronunciation + + align:start position:0% +any questions what's the pronunciation + + + align:start position:0% +any questions what's the pronunciation +of mobile or mobile mobile which one + + align:start position:0% +of mobile or mobile mobile which one + + + align:start position:0% +of mobile or mobile mobile which one +mobile in American English mob is more + + align:start position:0% +mobile in American English mob is more + + + align:start position:0% +mobile in American English mob is more +common whenever you have here the i e i + + align:start position:0% +common whenever you have here the i e i + + + align:start position:0% +common whenever you have here the i e i +e it's usually oh sterile sterile mobile + + align:start position:0% +e it's usually oh sterile sterile mobile + + + align:start position:0% +e it's usually oh sterile sterile mobile +ferle okay in TV people say mobile + + align:start position:0% +ferle okay in TV people say mobile + + + align:start position:0% +ferle okay in TV people say mobile +mobile T-Mobile mob T + + align:start position:0% +mobile T-Mobile mob T + + + align:start position:0% +mobile T-Mobile mob T +T-Mobile mobile T-Mobile T-Mobile me the + + align:start position:0% +T-Mobile mobile T-Mobile T-Mobile me the + + + align:start position:0% +T-Mobile mobile T-Mobile T-Mobile me the +phone + + align:start position:0% +phone + + + align:start position:0% +phone +T-Mobile it's T-Mobile right T-Mobile no + + align:start position:0% +T-Mobile it's T-Mobile right T-Mobile no + + + align:start position:0% +T-Mobile it's T-Mobile right T-Mobile no +it's not mobile people say T-Mobile + + align:start position:0% +it's not mobile people say T-Mobile + + + align:start position:0% +it's not mobile people say T-Mobile +T-Mobile T-Mobile yeah see again your + + align:start position:0% +T-Mobile T-Mobile yeah see again your + + + align:start position:0% +T-Mobile T-Mobile yeah see again your +brain is tricking you mobile people say + + align:start position:0% +brain is tricking you mobile people say + + + align:start position:0% +brain is tricking you mobile people say +mobile but you you look at it and you + + align:start position:0% +mobile but you you look at it and you + + + align:start position:0% +mobile but you you look at it and you +think okay it's m o b i l e it has to be + + align:start position:0% +think okay it's m o b i l e it has to be + + + align:start position:0% +think okay it's m o b i l e it has to be +mobile so people are saying mobile what + + align:start position:0% +mobile so people are saying mobile what + + + align:start position:0% +mobile so people are saying mobile what +you hear is Mo + + align:start position:0% +you hear is Mo + + + align:start position:0% +you hear is Mo +I think I mean mobile is not a wrong + + align:start position:0% +I think I mean mobile is not a wrong + + + align:start position:0% +I think I mean mobile is not a wrong +pronunciation but mobile mobile is more + + align:start position:0% +pronunciation but mobile mobile is more + + + align:start position:0% +pronunciation but mobile mobile is more +common in American English + + align:start position:0% +common in American English + + + align:start position:0% +common in American English +you say fertile fertile is okay it's not + + align:start position:0% +you say fertile fertile is okay it's not + + + align:start position:0% +you say fertile fertile is okay it's not +it's not the wrong pronunciation but + + align:start position:0% +it's not the wrong pronunciation but + + + align:start position:0% +it's not the wrong pronunciation but +it's just not that common in American + + align:start position:0% +it's just not that common in American + + + align:start position:0% +it's just not that common in American +English + + align:start position:0% +English + + + align:start position:0% +English +okay so if you on saying fertile that's + + align:start position:0% +okay so if you on saying fertile that's + + + align:start position:0% +okay so if you on saying fertile that's +okay but if you if people say fertile + + align:start position:0% +okay but if you if people say fertile + + + align:start position:0% +okay but if you if people say fertile +you need to understand it okay + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +today I have a cartoon + + align:start position:0% +today I have a cartoon + + + align:start position:0% +today I have a cartoon +that is really funny + + align:start position:0% +that is really funny + + + align:start position:0% +that is really funny +trust me this one will be funny if this + + align:start position:0% +trust me this one will be funny if this + + + align:start position:0% +trust me this one will be funny if this +is not funny I don't know what is + + align:start position:0% +is not funny I don't know what is + + + align:start position:0% +is not funny I don't know what is +but in order to make sure that this will + + align:start position:0% +but in order to make sure that this will + + + align:start position:0% +but in order to make sure that this will +be funny + + align:start position:0% +be funny + + + align:start position:0% +be funny +you will laugh + + align:start position:0% +you will laugh + + + align:start position:0% +you will laugh +I decided to do some priming + + align:start position:0% +I decided to do some priming + + + align:start position:0% +I decided to do some priming +uh you know the word + + align:start position:0% + + + + align:start position:0% + +everybody knows Batman right Batman and + + align:start position:0% +everybody knows Batman right Batman and + + + align:start position:0% +everybody knows Batman right Batman and +Robin + + align:start position:0% +Robin + + + align:start position:0% +Robin +Batman and Robin + + align:start position:0% +Batman and Robin + + + align:start position:0% +Batman and Robin +huh Robin + + align:start position:0% + + + + align:start position:0% + +stress is here ra so it becomes Robin + + align:start position:0% +stress is here ra so it becomes Robin + + + align:start position:0% +stress is here ra so it becomes Robin +Robin Robin or Robin Robin becomes a + + align:start position:0% +Robin Robin or Robin Robin becomes a + + + align:start position:0% +Robin Robin or Robin Robin becomes a +unstressed spell Robin + + align:start position:0% +unstressed spell Robin + + + align:start position:0% +unstressed spell Robin +it's not Rin not Rin Robin Robin okay + + align:start position:0% +it's not Rin not Rin Robin Robin okay + + + align:start position:0% +it's not Rin not Rin Robin Robin okay +Batman and Robin you know where you know + + align:start position:0% +Batman and Robin you know where you know + + + align:start position:0% +Batman and Robin you know where you know +where they live + + align:start position:0% +where they live + + + align:start position:0% +where they live +huh + + align:start position:0% + + + + align:start position:0% + +no no okay + + align:start position:0% + + + + align:start position:0% + +how do you read thisam + + align:start position:0% + + + + align:start position:0% + +goam + + align:start position:0% +goam + + + align:start position:0% +goam +k no no one's going to understand you + + align:start position:0% +k no no one's going to understand you + + + align:start position:0% +k no no one's going to understand you +it's not K it's not even goam if you say + + align:start position:0% +it's not K it's not even goam if you say + + + align:start position:0% +it's not K it's not even goam if you say +goam maybe you have a chance it's it's + + align:start position:0% +goam maybe you have a chance it's it's + + + align:start position:0% +goam maybe you have a chance it's it's +thumb it's voiceless okay Gotham Gotham + + align:start position:0% +thumb it's voiceless okay Gotham Gotham + + + align:start position:0% +thumb it's voiceless okay Gotham Gotham +you know you know what Gotham is you + + align:start position:0% +you know you know what Gotham is you + + + align:start position:0% +you know you know what Gotham is you +know what that means you know what that + + align:start position:0% +know what that means you know what that + + + align:start position:0% +know what that means you know what that +refers to + + align:start position:0% +refers to + + + align:start position:0% +refers to +it's actually a nickname for New York + + align:start position:0% +it's actually a nickname for New York + + + align:start position:0% +it's actually a nickname for New York +New York City okay so you know Batman + + align:start position:0% +New York City okay so you know Batman + + + align:start position:0% +New York City okay so you know Batman +and Robbie do you know where they live + + align:start position:0% +and Robbie do you know where they live + + + align:start position:0% +and Robbie do you know where they live +they live in New York huh + + align:start position:0% +they live in New York huh + + + align:start position:0% +they live in New York huh +I have no idea + + align:start position:0% +I have no idea + + + align:start position:0% +I have no idea +you know why it's I don't know American + + align:start position:0% +you know why it's I don't know American + + + align:start position:0% +you know why it's I don't know American +writer Washington Irving I think he + + align:start position:0% +writer Washington Irving I think he + + + align:start position:0% +writer Washington Irving I think he +started using this name I I don't know + + align:start position:0% +started using this name I I don't know + + + align:start position:0% +started using this name I I don't know +why so Batman and Robin they they live + + align:start position:0% +why so Batman and Robin they they live + + + align:start position:0% +why so Batman and Robin they they live +in New York + + align:start position:0% +in New York + + + align:start position:0% +in New York +every superhero lives in New York + + align:start position:0% +every superhero lives in New York + + + align:start position:0% +every superhero lives in New York +super man lives in New York you know + + align:start position:0% +super man lives in New York you know + + + align:start position:0% +super man lives in New York you know +Spider-Man + + align:start position:0% +Spider-Man + + + align:start position:0% +Spider-Man +York do you did you see Spider-Man too + + align:start position:0% + + + + align:start position:0% + +he he's really he's really smart you + + align:start position:0% +he he's really he's really smart you + + + align:start position:0% +he he's really he's really smart you +know right he's really into science + + align:start position:0% +know right he's really into science + + + align:start position:0% +know right he's really into science +he's really good at science but he can't + + align:start position:0% +he's really good at science but he can't + + + align:start position:0% +he's really good at science but he can't +I mean if he's really good at science he + + align:start position:0% +I mean if he's really good at science he + + + align:start position:0% +I mean if he's really good at science he +has to come to our school right + + align:start position:0% +has to come to our school right + + + align:start position:0% +has to come to our school right +but he goes to what school + + align:start position:0% +but he goes to what school + + + align:start position:0% +but he goes to what school +he goes to Columbia in New York why + + align:start position:0% +he goes to Columbia in New York why + + + align:start position:0% +he goes to Columbia in New York why +because he has to live in New York + + align:start position:0% +because he has to live in New York + + + align:start position:0% +because he has to live in New York +he can't come to Boston he can't come to + + align:start position:0% +he can't come to Boston he can't come to + + + align:start position:0% +he can't come to Boston he can't come to +MIT he can't go to Harvard why + + align:start position:0% + + + + align:start position:0% + +because super but why did yeah but + + align:start position:0% +because super but why did yeah but + + + align:start position:0% +because super but why did yeah but +Superman and Batman if they wanted to + + align:start position:0% +Superman and Batman if they wanted to + + + align:start position:0% +Superman and Batman if they wanted to +they could move here actually but not + + align:start position:0% +they could move here actually but not + + + align:start position:0% +they could move here actually but not +Spider-Man why + + align:start position:0% + + + + align:start position:0% + +very good very good Spider-Man he needs + + align:start position:0% +very good very good Spider-Man he needs + + + align:start position:0% +very good very good Spider-Man he needs +to so + + align:start position:0% +to so + + + align:start position:0% +to so +okay so this is how do you say thisam + + align:start position:0% + + + + align:start position:0% + +okay so now H stresses here becomes sh + + align:start position:0% +okay so now H stresses here becomes sh + + + align:start position:0% +okay so now H stresses here becomes sh +on stretch syllable Gotham Gotham very + + align:start position:0% +on stretch syllable Gotham Gotham very + + + align:start position:0% +on stretch syllable Gotham Gotham very +important if you say go go nobody's + + align:start position:0% +important if you say go go nobody's + + + align:start position:0% +important if you say go go nobody's +going to understand you Gotham Gotham + + align:start position:0% +going to understand you Gotham Gotham + + + align:start position:0% +going to understand you Gotham Gotham +okay + + align:start position:0% + + + + align:start position:0% + +so this is a cartoon + + align:start position:0% + + + + align:start position:0% + +this is about when you're supposed to + + align:start position:0% +this is about when you're supposed to + + + align:start position:0% +this is about when you're supposed to +laugh now + + align:start position:0% + + + + align:start position:0% + +come on + + align:start position:0% +come on + + + align:start position:0% +come on +this is not funny + + align:start position:0% + + + + align:start position:0% + +Batman and Robin right holy + + align:start position:0% +Batman and Robin right holy + + + align:start position:0% +Batman and Robin right holy +how how how would you read this + + align:start position:0% + + + + align:start position:0% + +okay how do you + + align:start position:0% + + + + align:start position:0% + +how do you how do you say this what's + + align:start position:0% +how do you how do you say this what's + + + align:start position:0% +how do you how do you say this what's +the stress syllable right okay we we're + + align:start position:0% +the stress syllable right okay we we're + + + align:start position:0% +the stress syllable right okay we we're +adding + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +Cent the stress is here now okay + + align:start position:0% + + + + align:start position:0% + +now here read this Batman and Robin are + + align:start position:0% +now here read this Batman and Robin are + + + align:start position:0% +now here read this Batman and Robin are +called in to free a Gotham from the grip + + align:start position:0% +called in to free a Gotham from the grip + + + align:start position:0% +called in to free a Gotham from the grip +of an evil graphic designer + + align:start position:0% +of an evil graphic designer + + + align:start position:0% +of an evil graphic designer +and the graphic designer in know graphic + + align:start position:0% +and the graphic designer in know graphic + + + align:start position:0% +and the graphic designer in know graphic +designer yes + + align:start position:0% +designer yes + + + align:start position:0% +designer yes +he or she made the sign like visit how + + align:start position:0% +he or she made the sign like visit how + + + align:start position:0% +he or she made the sign like visit how +do you read this + + align:start position:0% +do you read this + + + align:start position:0% +do you read this +God Hand God Hand + + align:start position:0% +God Hand God Hand + + + align:start position:0% +God Hand God Hand +it's not Gotham anymore godam + + align:start position:0% +it's not Gotham anymore godam + + + align:start position:0% +it's not Gotham anymore godam +got hand + + align:start position:0% + + + + align:start position:0% + +no let's not funny + + align:start position:0% +no let's not funny + + + align:start position:0% +no let's not funny +Gotham godam + + align:start position:0% +Gotham godam + + + align:start position:0% +Gotham godam +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now why am I doing this + + align:start position:0% + + + + align:start position:0% + +gotam + + align:start position:0% +gotam + + + align:start position:0% +gotam +well it's like got milk you know the + + align:start position:0% +well it's like got milk you know the + + + align:start position:0% +well it's like got milk you know the +commercial got milk got milk do we have + + align:start position:0% +commercial got milk got milk do we have + + + align:start position:0% +commercial got milk got milk do we have +milk got milk okay got hand so we have H + + align:start position:0% +milk got milk okay got hand so we have H + + + align:start position:0% +milk got milk okay got hand so we have H +got ham got ham got ham now here you + + align:start position:0% +got ham got ham got ham now here you + + + align:start position:0% +got ham got ham got ham now here you +can't say got h + + align:start position:0% + + + + align:start position:0% + +just + + align:start position:0% +just + + + align:start position:0% +just +got ham got ham got ham but here you + + align:start position:0% +got ham got ham got ham but here you + + + align:start position:0% +got ham got ham got ham but here you +have to say God thumb + + align:start position:0% +have to say God thumb + + + align:start position:0% +have to say God thumb +okay the Val gets reduced but here the + + align:start position:0% +okay the Val gets reduced but here the + + + align:start position:0% +okay the Val gets reduced but here the +Val is not reduced because this is a + + align:start position:0% +Val is not reduced because this is a + + + align:start position:0% +Val is not reduced because this is a +compound + + align:start position:0% +compound + + + align:start position:0% +compound +compound + + align:start position:0% +compound + + + align:start position:0% +compound +what's a compound + + align:start position:0% +what's a compound + + + align:start position:0% +what's a compound +what's a compound so compound + + align:start position:0% +what's a compound so compound + + + align:start position:0% +what's a compound so compound +if you turn to our textbook B on page + + align:start position:0% +if you turn to our textbook B on page + + + align:start position:0% +if you turn to our textbook B on page + + align:start position:0% + + + + align:start position:0% + +page 107 in your textbook + + align:start position:0% + + + + align:start position:0% + +page 107 + + align:start position:0% + + + + align:start position:0% + +page 107 + + align:start position:0% + + + + align:start position:0% + +page 107 page 107 does anybody want to + + align:start position:0% +page 107 page 107 does anybody want to + + + align:start position:0% +page 107 page 107 does anybody want to +read page 107 for us a compound noun is + + align:start position:0% +read page 107 for us a compound noun is + + + align:start position:0% +read page 107 for us a compound noun is +a compound noun is + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +the compound noun is the sequence of two + + align:start position:0% +the compound noun is the sequence of two + + + align:start position:0% +the compound noun is the sequence of two +or more was + + align:start position:0% +or more was + + + align:start position:0% +or more was +that that together have a new meaning + + align:start position:0% +that that together have a new meaning + + + align:start position:0% +that that together have a new meaning +and function as a single + + align:start position:0% +and function as a single + + + align:start position:0% +and function as a single +you okay read on the second element of + + align:start position:0% +you okay read on the second element of + + + align:start position:0% +you okay read on the second element of +word of the of the is a n the first + + align:start position:0% +word of the of the is a n the first + + + align:start position:0% +word of the of the is a n the first +element is usually a n but may also be + + align:start position:0% +element is usually a n but may also be + + + align:start position:0% +element is usually a n but may also be +another part of speech a compound may be + + align:start position:0% +another part of speech a compound may be + + + align:start position:0% +another part of speech a compound may be +written as one or two words okay so a + + align:start position:0% +written as one or two words okay so a + + + align:start position:0% +written as one or two words okay so a +compound noun is a sequence of two or + + align:start position:0% +compound noun is a sequence of two or + + + align:start position:0% +compound noun is a sequence of two or +more words that together have a new + + align:start position:0% +more words that together have a new + + + align:start position:0% +more words that together have a new +meaning and function as a single noun + + align:start position:0% +meaning and function as a single noun + + + align:start position:0% +meaning and function as a single noun +function is a single noun okay that's a + + align:start position:0% +function is a single noun okay that's a + + + align:start position:0% +function is a single noun okay that's a +compound we turn to and we have some + + align:start position:0% +compound we turn to and we have some + + + align:start position:0% +compound we turn to and we have some +examples roommate newspaper School Bus + + align:start position:0% +examples roommate newspaper School Bus + + + align:start position:0% +examples roommate newspaper School Bus +Waste Paper basket + + align:start position:0% +Waste Paper basket + + + align:start position:0% +Waste Paper basket +but the important thing about compound + + align:start position:0% +but the important thing about compound + + + align:start position:0% +but the important thing about compound +nouns is that if you turn to page 108 + + align:start position:0% + + + + align:start position:0% + +we have the word weekends right + + align:start position:0% + + + + align:start position:0% + +this is a compound this is not a + + align:start position:0% +this is a compound this is not a + + + align:start position:0% +this is a compound this is not a +compound this is a compound this is this + + align:start position:0% +compound this is a compound this is this + + + align:start position:0% +compound this is a compound this is this +is not a compound because we have two + + align:start position:0% +is not a compound because we have two + + + align:start position:0% +is not a compound because we have two +words here we + + align:start position:0% +words here we + + + align:start position:0% +words here we +and and two words that we could actually + + align:start position:0% +and and two words that we could actually + + + align:start position:0% +and and two words that we could actually +recognize right + + align:start position:0% +recognize right + + + align:start position:0% +recognize right +this is one word where is the stress we + + align:start position:0% +this is one word where is the stress we + + + align:start position:0% +this is one word where is the stress we +right so you say we + + align:start position:0% +right so you say we + + + align:start position:0% +right so you say we +we okay in a normal word single word if + + align:start position:0% +we okay in a normal word single word if + + + align:start position:0% +we okay in a normal word single word if +you have a stressed syllable unstressed + + align:start position:0% +you have a stressed syllable unstressed + + + align:start position:0% +you have a stressed syllable unstressed +syllables becomes a right weaken weaken + + align:start position:0% +syllables becomes a right weaken weaken + + + align:start position:0% +syllables becomes a right weaken weaken +but in a compound noun the second in a + + align:start position:0% +but in a compound noun the second in a + + + align:start position:0% +but in a compound noun the second in a +compound noun or noun compounds it's + + align:start position:0% +compound noun or noun compounds it's + + + align:start position:0% +compound noun or noun compounds it's +always the first one that gets stress + + align:start position:0% +always the first one that gets stress + + + align:start position:0% +always the first one that gets stress +the second one has a secondary stress + + align:start position:0% +the second one has a secondary stress + + + align:start position:0% +the second one has a secondary stress +okay so you do not say we weeken you say + + align:start position:0% +okay so you do not say we weeken you say + + + align:start position:0% +okay so you do not say we weeken you say +we + + align:start position:0% +we + + + align:start position:0% +we +we okay weekend weeken we okay so Gotham + + align:start position:0% +we okay weekend weeken we okay so Gotham + + + align:start position:0% +we okay weekend weeken we okay so Gotham +one word becomes goam + + align:start position:0% +one word becomes goam + + + align:start position:0% +one word becomes goam +but God ham God ham God ham okay it's + + align:start position:0% +but God ham God ham God ham okay it's + + + align:start position:0% +but God ham God ham God ham okay it's +God ham + + align:start position:0% + + + + align:start position:0% + +that's very important okay now + + align:start position:0% + + + + align:start position:0% + +you could turn to + + align:start position:0% + + + + align:start position:0% + +page 10 uh page 63 in your course pocket + + align:start position:0% +page 10 uh page 63 in your course pocket + + + align:start position:0% +page 10 uh page 63 in your course pocket +compounds + + align:start position:0% + + + + align:start position:0% + +so we actually have four different + + align:start position:0% +so we actually have four different + + + align:start position:0% +so we actually have four different +compounds one the most common one is the + + align:start position:0% +compounds one the most common one is the + + + align:start position:0% +compounds one the most common one is the +noun compounds we say sometimes noun + + align:start position:0% +noun compounds we say sometimes noun + + + align:start position:0% +noun compounds we say sometimes noun +compounds or compound nouns both are + + align:start position:0% +compounds or compound nouns both are + + + align:start position:0% +compounds or compound nouns both are +interchangeable okay the most common + + align:start position:0% +interchangeable okay the most common + + + align:start position:0% +interchangeable okay the most common +ones are noun compounds we also have + + align:start position:0% +ones are noun compounds we also have + + + align:start position:0% +ones are noun compounds we also have +verb compounds adjective compounds and + + align:start position:0% +verb compounds adjective compounds and + + + align:start position:0% +verb compounds adjective compounds and +adverb compounds okay adverb compounds + + align:start position:0% +adverb compounds okay adverb compounds + + + align:start position:0% +adverb compounds okay adverb compounds +are the least common one and so we're + + align:start position:0% +are the least common one and so we're + + + align:start position:0% +are the least common one and so we're +not really going to talk about uh adverb + + align:start position:0% +not really going to talk about uh adverb + + + align:start position:0% +not really going to talk about uh adverb +compounds + + align:start position:0% +compounds + + + align:start position:0% +compounds +now compounds the most important thing + + align:start position:0% +now compounds the most important thing + + + align:start position:0% +now compounds the most important thing +that you want to remember is + + align:start position:0% +that you want to remember is + + + align:start position:0% +that you want to remember is +the place of stress where is the stress + + align:start position:0% +the place of stress where is the stress + + + align:start position:0% +the place of stress where is the stress +first first one first one that's very + + align:start position:0% +first first one first one that's very + + + align:start position:0% +first first one first one that's very +important okay + + align:start position:0% + + + + align:start position:0% + +noun compounds can actually uh consist + + align:start position:0% +noun compounds can actually uh consist + + + align:start position:0% +noun compounds can actually uh consist +of two nouns like a or adjective and + + align:start position:0% +of two nouns like a or adjective and + + + align:start position:0% +of two nouns like a or adjective and +nouns like B so first first a toothbrush + + align:start position:0% +nouns like B so first first a toothbrush + + + align:start position:0% +nouns like B so first first a toothbrush +repeat after me toothbrush toothbrush + + align:start position:0% +repeat after me toothbrush toothbrush + + + align:start position:0% +repeat after me toothbrush toothbrush +Window Seat Window Seat airplane + + align:start position:0% +Window Seat Window Seat airplane + + + align:start position:0% +Window Seat Window Seat airplane +airplane laundry basket laundry basket + + align:start position:0% +airplane laundry basket laundry basket + + + align:start position:0% +airplane laundry basket laundry basket +okay + + align:start position:0% + + + + align:start position:0% + +let's get this B we could also have + + align:start position:0% +let's get this B we could also have + + + align:start position:0% +let's get this B we could also have +adjectives and noun together and they + + align:start position:0% +adjectives and noun together and they + + + align:start position:0% +adjectives and noun together and they +can form a compound okay it could be + + align:start position:0% +can form a compound okay it could be + + + align:start position:0% +can form a compound okay it could be +written as one word or it could be + + align:start position:0% +written as one word or it could be + + + align:start position:0% +written as one word or it could be +written as two different two words + + align:start position:0% + + + + align:start position:0% + +blackb + + align:start position:0% +blackb + + + align:start position:0% +blackb +dark room dark room Chief skates Chief + + align:start position:0% +dark room dark room Chief skates Chief + + + align:start position:0% +dark room dark room Chief skates Chief +Gates White House White House English + + align:start position:0% +Gates White House White House English + + + align:start position:0% +Gates White House White House English +teacher + + align:start position:0% +teacher + + + align:start position:0% +teacher +English teacher head doctor head doctor + + align:start position:0% +English teacher head doctor head doctor + + + align:start position:0% +English teacher head doctor head doctor +now the question is okay so what's + + align:start position:0% +now the question is okay so what's + + + align:start position:0% +now the question is okay so what's +difference if you have + + align:start position:0% + + + + align:start position:0% + +if you have an adjective and noun that + + align:start position:0% +if you have an adjective and noun that + + + align:start position:0% +if you have an adjective and noun that +do not function as a compound noun + + align:start position:0% +do not function as a compound noun + + + align:start position:0% +do not function as a compound noun +compound the stress is where in the noun + + align:start position:0% +compound the stress is where in the noun + + + align:start position:0% +compound the stress is where in the noun +okay uh we haven't really talked about + + align:start position:0% +okay uh we haven't really talked about + + + align:start position:0% +okay uh we haven't really talked about +this yet yet we haven't talked about + + align:start position:0% +this yet yet we haven't talked about + + + align:start position:0% +this yet yet we haven't talked about +this yet but uh usually you put most + + align:start position:0% +this yet but uh usually you put most + + + align:start position:0% +this yet but uh usually you put most +stress on the last content word okay + + align:start position:0% +stress on the last content word okay + + + align:start position:0% +stress on the last content word okay +adjective is a Content word and noun is + + align:start position:0% +adjective is a Content word and noun is + + + align:start position:0% +adjective is a Content word and noun is +a Content word we have adjective and + + align:start position:0% +a Content word we have adjective and + + + align:start position:0% +a Content word we have adjective and +noun okay we put more stress on the last + + align:start position:0% +noun okay we put more stress on the last + + + align:start position:0% +noun okay we put more stress on the last +content One content word usually so + + align:start position:0% +content One content word usually so + + + align:start position:0% +content One content word usually so +that's why the noun gets more stress + + align:start position:0% +that's why the noun gets more stress + + + align:start position:0% +that's why the noun gets more stress +okay so how do you say this black black + + align:start position:0% +okay so how do you say this black black + + + align:start position:0% +okay so how do you say this black black +board black dark room + + align:start position:0% + + + + align:start position:0% + +what house + + align:start position:0% +what house + + + align:start position:0% +what house +Engish teacher + + align:start position:0% +Engish teacher + + + align:start position:0% +Engish teacher +doctor okay so I mean what's what's a + + align:start position:0% +doctor okay so I mean what's what's a + + + align:start position:0% +doctor okay so I mean what's what's a +black board + + align:start position:0% +black board + + + align:start position:0% +black board +that's a black board right + + align:start position:0% +that's a black board right + + + align:start position:0% +that's a black board right +that's not even black is it but we say + + align:start position:0% +that's not even black is it but we say + + + align:start position:0% +that's not even black is it but we say +Blackboard right but Blackport is what's + + align:start position:0% +Blackboard right but Blackport is what's + + + align:start position:0% +Blackboard right but Blackport is what's +a black board + + align:start position:0% + + + + align:start position:0% + +board that is black right what's a dark + + align:start position:0% +board that is black right what's a dark + + + align:start position:0% +board that is black right what's a dark +room + + align:start position:0% +room + + + align:start position:0% +room +Theo + + align:start position:0% +Theo + + + align:start position:0% +Theo +for the photo you + + align:start position:0% +for the photo you + + + align:start position:0% +for the photo you +the develop photos pictures dark room + + align:start position:0% +the develop photos pictures dark room + + + align:start position:0% +the develop photos pictures dark room +you need a dark room to develop photos + + align:start position:0% +you need a dark room to develop photos + + + align:start position:0% +you need a dark room to develop photos +dark room you can't just be + + align:start position:0% +dark room you can't just be + + + align:start position:0% +dark room you can't just be +any room that's dark I think you need + + align:start position:0% +any room that's dark I think you need + + + align:start position:0% +any room that's dark I think you need +more things okay I could make this a + + align:start position:0% +more things okay I could make this a + + + align:start position:0% +more things okay I could make this a +dark room by turning off the lights but + + align:start position:0% +dark room by turning off the lights but + + + align:start position:0% +dark room by turning off the lights but +I can't make it a dark room + + align:start position:0% +I can't make it a dark room + + + align:start position:0% +I can't make it a dark room +okay what's a chip skate + + align:start position:0% +okay what's a chip skate + + + align:start position:0% +okay what's a chip skate +a chip skate or chip skate two chip + + align:start position:0% +a chip skate or chip skate two chip + + + align:start position:0% +a chip skate or chip skate two chip +skates what's a chip skate someone + + align:start position:0% +skates what's a chip skate someone + + + align:start position:0% +skates what's a chip skate someone +do not money okay someone who's cheap + + align:start position:0% +do not money okay someone who's cheap + + + align:start position:0% +do not money okay someone who's cheap +someone who who's stingy someone who's + + align:start position:0% +someone who who's stingy someone who's + + + align:start position:0% +someone who who's stingy someone who's +stingy okay who's not who doesn't want + + align:start position:0% +stingy okay who's not who doesn't want + + + align:start position:0% +stingy okay who's not who doesn't want +to spend his money uh that well + + align:start position:0% +to spend his money uh that well + + + align:start position:0% +to spend his money uh that well +cheap skates it's skates that are cheap + + align:start position:0% + + + + align:start position:0% + +who lives in the White House + + align:start position:0% +who lives in the White House + + + align:start position:0% +who lives in the White House +huh + + align:start position:0% +huh + + + align:start position:0% +huh +George Bush George W bush Okay W bush he + + align:start position:0% +George Bush George W bush Okay W bush he + + + align:start position:0% +George Bush George W bush Okay W bush he +lives in the White House + + align:start position:0% +lives in the White House + + + align:start position:0% +lives in the White House +I live in a white house I live in a I'm + + align:start position:0% +I live in a white house I live in a I'm + + + align:start position:0% +I live in a white house I live in a I'm +serious I live in a white house but + + align:start position:0% +serious I live in a white house but + + + align:start position:0% +serious I live in a white house but +nobody lives in the White House except + + align:start position:0% +nobody lives in the White House except + + + align:start position:0% +nobody lives in the White House except +George Bush right now okay and it'll be + + align:start position:0% +George Bush right now okay and it'll be + + + align:start position:0% +George Bush right now okay and it'll be +that way for the next four years too + + align:start position:0% +that way for the next four years too + + + align:start position:0% +that way for the next four years too +White House White House live in the + + align:start position:0% +White House White House live in the + + + align:start position:0% +White House White House live in the +White House okay George Bush lives in + + align:start position:0% +White House okay George Bush lives in + + + align:start position:0% +White House okay George Bush lives in +the White House + + align:start position:0% +the White House + + + align:start position:0% +the White House +can say the whole sentence George + + align:start position:0% +can say the whole sentence George + + + align:start position:0% +can say the whole sentence George +white house but Isaiah isah lives in a + + align:start position:0% +white house but Isaiah isah lives in a + + + align:start position:0% +white house but Isaiah isah lives in a +White House Liv in house + + align:start position:0% + + + + align:start position:0% + +Isaiah is an English teacher or English + + align:start position:0% +Isaiah is an English teacher or English + + + align:start position:0% +Isaiah is an English teacher or English +teacher English teacher English teacher + + align:start position:0% +teacher English teacher English teacher + + + align:start position:0% +teacher English teacher English teacher +English teacher Isaiah I'm I'm an + + align:start position:0% +English teacher Isaiah I'm I'm an + + + align:start position:0% +English teacher Isaiah I'm I'm an +English teacher from Korea okay I'm not + + align:start position:0% +English teacher from Korea okay I'm not + + + align:start position:0% +English teacher from Korea okay I'm not +an English teacher what's an English + + align:start position:0% +an English teacher what's an English + + + align:start position:0% +an English teacher what's an English +teacher teer from teacher from England + + align:start position:0% +teacher teer from teacher from England + + + align:start position:0% +teacher teer from teacher from England +teacher from England right English + + align:start position:0% +teacher from England right English + + + align:start position:0% +teacher from England right English +teacher is someone who + + align:start position:0% +teacher is someone who + + + align:start position:0% +teacher is someone who +teaches English Okay + + align:start position:0% +teaches English Okay + + + align:start position:0% +teaches English Okay +rep English teacher English teacher okay + + align:start position:0% +rep English teacher English teacher okay + + + align:start position:0% +rep English teacher English teacher okay +so I'm an English teacher I'm an English + + align:start position:0% +so I'm an English teacher I'm an English + + + align:start position:0% +so I'm an English teacher I'm an English +teacher not I'm not an English teacher + + align:start position:0% +teacher not I'm not an English teacher + + + align:start position:0% +teacher not I'm not an English teacher +I'm a Korean teacher but I'm not a Kore + + align:start position:0% +I'm a Korean teacher but I'm not a Kore + + + align:start position:0% +I'm a Korean teacher but I'm not a Kore +Korean teacher okay + + align:start position:0% + + + + align:start position:0% + +well korean-american teacher + + align:start position:0% +well korean-american teacher + + + align:start position:0% +well korean-american teacher +what's up head doctor doctor head doctor + + align:start position:0% +what's up head doctor doctor head doctor + + + align:start position:0% +what's up head doctor doctor head doctor +head doctor + + align:start position:0% + + + + align:start position:0% + +Chief + + align:start position:0% +Chief + + + align:start position:0% +Chief +doctor chief chief of staff chief chief + + align:start position:0% +doctor chief chief of staff chief chief + + + align:start position:0% +doctor chief chief of staff chief chief +would be doctor head doctor Chief is + + align:start position:0% +would be doctor head doctor Chief is + + + align:start position:0% +would be doctor head doctor Chief is +head doctor okay you can say my brother + + align:start position:0% +head doctor okay you can say my brother + + + align:start position:0% +head doctor okay you can say my brother +is a head doctor doctor my brother is a + + align:start position:0% +is a head doctor doctor my brother is a + + + align:start position:0% +is a head doctor doctor my brother is a +head doctor my brother is the head my + + align:start position:0% +head doctor my brother is the head my + + + align:start position:0% +head doctor my brother is the head my +brother is a head doctor uh uh at his + + align:start position:0% +brother is a head doctor uh uh at his + + + align:start position:0% +brother is a head doctor uh uh at his +Hospital something like that that but + + align:start position:0% +Hospital something like that that but + + + align:start position:0% +Hospital something like that that but +you could say my my my brother is a head + + align:start position:0% +you could say my my my brother is a head + + + align:start position:0% +you could say my my my brother is a head +doctor head doctor + + align:start position:0% +doctor head doctor + + + align:start position:0% +doctor head doctor +um I mean that's usually for kids you + + align:start position:0% +um I mean that's usually for kids you + + + align:start position:0% +um I mean that's usually for kids you +would you should say instead of head + + align:start position:0% +would you should say instead of head + + + align:start position:0% +would you should say instead of head +doctor + + align:start position:0% + + + + align:start position:0% + +how would you read this + + align:start position:0% +how would you read this + + + align:start position:0% +how would you read this +where is the stress okay the first thing + + align:start position:0% +where is the stress okay the first thing + + + align:start position:0% +where is the stress okay the first thing +you want to do is what + + align:start position:0% +you want to do is what + + + align:start position:0% +you want to do is what +find out the stress right okay where is + + align:start position:0% +find out the stress right okay where is + + + align:start position:0% +find out the stress right okay where is +the stress + + align:start position:0% + + + + align:start position:0% + +K okay Kai so + + align:start position:0% +K okay Kai so + + + align:start position:0% +K okay Kai so +everything else becomes what so we're + + align:start position:0% +everything else becomes what so we're + + + align:start position:0% +everything else becomes what so we're +going to say Kai okay we have this B + + align:start position:0% +going to say Kai okay we have this B + + + align:start position:0% +going to say Kai okay we have this B +this B this B what are you going to do + + align:start position:0% + + + + align:start position:0% + +right so + + align:start position:0% + + + + align:start position:0% + +what happens here what happens here + + align:start position:0% +what happens here what happens here + + + align:start position:0% +what happens here what happens here +psychiatrist + + align:start position:0% +psychiatrist + + + align:start position:0% +psychiatrist +psychiatrist Psych psychiatrist + + align:start position:0% +psychiatrist Psych psychiatrist + + + align:start position:0% +psychiatrist Psych psychiatrist +psychiatrist okay but here actuallyy + + align:start position:0% + + + + align:start position:0% + +people say also I actually say + + align:start position:0% +people say also I actually say + + + align:start position:0% +people say also I actually say +psychiatrist I say psychiatrist Psy + + align:start position:0% +psychiatrist I say psychiatrist Psy + + + align:start position:0% +psychiatrist I say psychiatrist Psy +psychiatrist okay so Krist + + align:start position:0% +psychiatrist okay so Krist + + + align:start position:0% +psychiatrist okay so Krist +psychiatrist + + align:start position:0% +psychiatrist + + + align:start position:0% +psychiatrist +so which one is a psychiatrist + + align:start position:0% +so which one is a psychiatrist + + + align:start position:0% +so which one is a psychiatrist +which one doctor head doctor doctor okay + + align:start position:0% +which one doctor head doctor doctor okay + + + align:start position:0% +which one doctor head doctor doctor okay +doctor + + align:start position:0% +doctor + + + align:start position:0% +doctor +head doctor doctor okay now we could + + align:start position:0% +head doctor doctor okay now we could + + + align:start position:0% +head doctor doctor okay now we could +have simple compounds or complex + + align:start position:0% +have simple compounds or complex + + + align:start position:0% +have simple compounds or complex +compounds + + align:start position:0% +compounds + + + align:start position:0% +compounds +airplane airplane wing airplane wing + + align:start position:0% +airplane airplane wing airplane wing + + + align:start position:0% +airplane airplane wing airplane wing +cowboy cowboy hat hot dog hot dog bun + + align:start position:0% +cowboy cowboy hat hot dog hot dog bun + + + align:start position:0% +cowboy cowboy hat hot dog hot dog bun +tap Dan tap School tap School these are + + align:start position:0% +tap Dan tap School tap School these are + + + align:start position:0% +tap Dan tap School tap School these are +complex compounds still + + align:start position:0% +complex compounds still + + + align:start position:0% +complex compounds still +uh the word that gets most stressed is + + align:start position:0% +uh the word that gets most stressed is + + + align:start position:0% +uh the word that gets most stressed is +the first n airplane wing cowboy hat Hot + + align:start position:0% +the first n airplane wing cowboy hat Hot + + + align:start position:0% +the first n airplane wing cowboy hat Hot +Dog tap School okay + + align:start position:0% +Dog tap School okay + + + align:start position:0% +Dog tap School okay +hot a + + align:start position:0% +hot a + + + align:start position:0% +hot a +hot you know you know what a hot dog is + + align:start position:0% +hot you know you know what a hot dog is + + + align:start position:0% +hot you know you know what a hot dog is +Right hot dog hot dog the bread the + + align:start position:0% +Right hot dog hot dog the bread the + + + align:start position:0% +Right hot dog hot dog the bread the +bread Bunny's bread + + align:start position:0% +bread Bunny's bread + + + align:start position:0% +bread Bunny's bread +you like hot dogs yes not hot dogs right + + align:start position:0% +you like hot dogs yes not hot dogs right + + + align:start position:0% +you like hot dogs yes not hot dogs right +hot dogs hot dogs not hot dogs right + + align:start position:0% +hot dogs hot dogs not hot dogs right + + + align:start position:0% +hot dogs hot dogs not hot dogs right +hot dogs + + align:start position:0% + + + + align:start position:0% + +yeah + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +so how would you say this the first one + + align:start position:0% +so how would you say this the first one + + + align:start position:0% +so how would you say this the first one +how would you say the + + align:start position:0% +how would you say the + + + align:start position:0% +how would you say the +how you say how' you say the first one + + align:start position:0% + + + + align:start position:0% + +okay Jin can you say the first sentence + + align:start position:0% + + + + align:start position:0% + +very good black bird nest okay black + + align:start position:0% +very good black bird nest okay black + + + align:start position:0% +very good black bird nest okay black +bird nest black bird nest okay y can you + + align:start position:0% +bird nest black bird nest okay y can you + + + align:start position:0% +bird nest black bird nest okay y can you +say the second sentence + + align:start position:0% + + + + align:start position:0% + +black nest + + align:start position:0% + + + + align:start position:0% + +bird nest black bird nest black bird + + align:start position:0% +bird nest black bird nest black bird + + + align:start position:0% +bird nest black bird nest black bird +bird n what kind of nest first okay + + align:start position:0% +bird n what kind of nest first okay + + + align:start position:0% +bird n what kind of nest first okay +compound is actually + + align:start position:0% +compound is actually + + + align:start position:0% +compound is actually +trying to figure out what you you look + + align:start position:0% +trying to figure out what you you look + + + align:start position:0% +trying to figure out what you you look +at a word right or two ad adjective noun + + align:start position:0% +at a word right or two ad adjective noun + + + align:start position:0% +at a word right or two ad adjective noun +it's actually very difficult uh to + + align:start position:0% +it's actually very difficult uh to + + + align:start position:0% +it's actually very difficult uh to +figure out whether this is compound noun + + align:start position:0% +figure out whether this is compound noun + + + align:start position:0% +figure out whether this is compound noun +or adjective and adjective and noun it's + + align:start position:0% +or adjective and adjective and noun it's + + + align:start position:0% +or adjective and adjective and noun it's +actually very difficult one thing you + + align:start position:0% +actually very difficult one thing you + + + align:start position:0% +actually very difficult one thing you +could do is to ask yourself if you could + + align:start position:0% +could do is to ask yourself if you could + + + align:start position:0% +could do is to ask yourself if you could +say what kind of Nest is it you can say + + align:start position:0% +say what kind of Nest is it you can say + + + align:start position:0% +say what kind of Nest is it you can say +it's a birth Nest then it's a compound + + align:start position:0% +it's a birth Nest then it's a compound + + + align:start position:0% +it's a birth Nest then it's a compound +down there that's just one of many ways + + align:start position:0% +down there that's just one of many ways + + + align:start position:0% +down there that's just one of many ways +if you say what kind of brush is it it's + + align:start position:0% +if you say what kind of brush is it it's + + + align:start position:0% +if you say what kind of brush is it it's +a toothbrush what kind of brush is it + + align:start position:0% +a toothbrush what kind of brush is it + + + align:start position:0% +a toothbrush what kind of brush is it +it's a hair brush paintbrush then then + + align:start position:0% +it's a hair brush paintbrush then then + + + align:start position:0% +it's a hair brush paintbrush then then +it's a compound now right you could say + + align:start position:0% +it's a compound now right you could say + + + align:start position:0% +it's a compound now right you could say +what kind of Nest is it right it's a + + align:start position:0% +what kind of Nest is it right it's a + + + align:start position:0% +what kind of Nest is it right it's a +black bird nest birdest so here it's a + + align:start position:0% +black bird nest birdest so here it's a + + + align:start position:0% +black bird nest birdest so here it's a +bird nest that is black but here it's + + align:start position:0% +bird nest that is black but here it's + + + align:start position:0% +bird nest that is black but here it's +black bird is a kind of kind of bird + + align:start position:0% +black bird is a kind of kind of bird + + + align:start position:0% +black bird is a kind of kind of bird +it's a black bird nest so you say black + + align:start position:0% +it's a black bird nest so you say black + + + align:start position:0% +it's a black bird nest so you say black +bird nest + + align:start position:0% +bird nest + + + align:start position:0% +bird nest +only only the Nast is Right which one + + align:start position:0% +only only the Nast is Right which one + + + align:start position:0% +only only the Nast is Right which one +this one the second one + + align:start position:0% +this one the second one + + + align:start position:0% +this one the second one +second one + + align:start position:0% +second one + + + align:start position:0% +second one +a black what is + + align:start position:0% + + + + align:start position:0% + +it's a black + + align:start position:0% +it's a black + + + align:start position:0% +it's a black +is + + align:start position:0% +is + + + align:start position:0% +is +nestest is + + align:start position:0% + + + + align:start position:0% + +it's a flat bird nest yes Nest is black + + align:start position:0% +it's a flat bird nest yes Nest is black + + + align:start position:0% +it's a flat bird nest yes Nest is black +not a bird it's a flat bird nest the + + align:start position:0% +not a bird it's a flat bird nest the + + + align:start position:0% +not a bird it's a flat bird nest the +black bird nest not not not the bird + + align:start position:0% +black bird nest not not not the bird + + + align:start position:0% +black bird nest not not not the bird +nest is black nest is it's a nest that + + align:start position:0% +nest is black nest is it's a nest that + + + align:start position:0% +nest is black nest is it's a nest that +is black it's a bird nest that is black + + align:start position:0% +is black it's a bird nest that is black + + + align:start position:0% +is black it's a bird nest that is black +yes okay it's a it's a + + align:start position:0% +yes okay it's a it's a + + + align:start position:0% +yes okay it's a it's a +okay + + align:start position:0% +okay + + + align:start position:0% +okay +now + + align:start position:0% +now + + + align:start position:0% +now +verb compounds + + align:start position:0% + + + + align:start position:0% + +verb compounds what you want to remember + + align:start position:0% +verb compounds what you want to remember + + + align:start position:0% +verb compounds what you want to remember +is just like noun compounds what do you + + align:start position:0% +is just like noun compounds what do you + + + align:start position:0% +is just like noun compounds what do you +do with the noun compounds where is the + + align:start position:0% +do with the noun compounds where is the + + + align:start position:0% +do with the noun compounds where is the +stress + + align:start position:0% +stress + + + align:start position:0% +stress +uh the first first one or the second one + + align:start position:0% +uh the first first one or the second one + + + align:start position:0% +uh the first first one or the second one +first one it doesn't matter whether it's + + align:start position:0% +first one it doesn't matter whether it's + + + align:start position:0% +first one it doesn't matter whether it's +adjective or noun the first one is + + align:start position:0% +adjective or noun the first one is + + + align:start position:0% +adjective or noun the first one is +always stressed in a in a verb compound + + align:start position:0% +always stressed in a in a verb compound + + + align:start position:0% +always stressed in a in a verb compound +it's all it's also the same you stress + + align:start position:0% +it's all it's also the same you stress + + + align:start position:0% +it's all it's also the same you stress +the first word okay you stress the first + + align:start position:0% +the first word okay you stress the first + + + align:start position:0% +the first word okay you stress the first +one here + + align:start position:0% + + + + align:start position:0% + +now this is becoming this becomes + + align:start position:0% +now this is becoming this becomes + + + align:start position:0% +now this is becoming this becomes +important because last week we learned + + align:start position:0% +important because last week we learned + + + align:start position:0% +important because last week we learned +that when you have a prefix in a verb + + align:start position:0% +that when you have a prefix in a verb + + + align:start position:0% +that when you have a prefix in a verb +What Happens prefix usually + + align:start position:0% +What Happens prefix usually + + + align:start position:0% +What Happens prefix usually +no no stress right so you say + + align:start position:0% +no no stress right so you say + + + align:start position:0% +no no stress right so you say +overflow overflow ins insult + + align:start position:0% +overflow overflow ins insult + + + align:start position:0% +overflow overflow ins insult +conduct + + align:start position:0% +conduct + + + align:start position:0% +conduct +protest + + align:start position:0% +protest + + + align:start position:0% +protest +record record okay so you don't want to + + align:start position:0% +record record okay so you don't want to + + + align:start position:0% +record record okay so you don't want to +get those two mixed up okay that's a + + align:start position:0% +get those two mixed up okay that's a + + + align:start position:0% +get those two mixed up okay that's a +very common mistake students learn okay + + align:start position:0% +very common mistake students learn okay + + + align:start position:0% +very common mistake students learn okay +prefix wow in a verb + + align:start position:0% +prefix wow in a verb + + + align:start position:0% +prefix wow in a verb +you you stretch the second one okay oh + + align:start position:0% +you you stretch the second one okay oh + + + align:start position:0% +you you stretch the second one okay oh +that's easy and you you read something + + align:start position:0% +that's easy and you you read something + + + align:start position:0% +that's easy and you you read something +like this how sit and C goes right no + + align:start position:0% +like this how sit and C goes right no + + + align:start position:0% +like this how sit and C goes right no +these are compounds compounds compounds + + align:start position:0% +these are compounds compounds compounds + + + align:start position:0% +these are compounds compounds compounds +and words that has prefixes they are + + align:start position:0% +and words that has prefixes they are + + + align:start position:0% +and words that has prefixes they are +different + + align:start position:0% +different + + + align:start position:0% +different +okay so + + align:start position:0% +okay so + + + align:start position:0% +okay so +Fact one compound nouns and verbs are + + align:start position:0% +Fact one compound nouns and verbs are + + + align:start position:0% +Fact one compound nouns and verbs are +always stressed in the first word there + + align:start position:0% +always stressed in the first word there + + + align:start position:0% +always stressed in the first word there +are no exceptions compound nouns and + + align:start position:0% +are no exceptions compound nouns and + + + align:start position:0% +are no exceptions compound nouns and +verbs always stressed in this uh first + + align:start position:0% +verbs always stressed in this uh first + + + align:start position:0% +verbs always stressed in this uh first +word fact two + + align:start position:0% +word fact two + + + align:start position:0% +word fact two +prefixes are not stressed in verbs okay + + align:start position:0% +prefixes are not stressed in verbs okay + + + align:start position:0% +prefixes are not stressed in verbs okay +there are no exceptions prefixes are + + align:start position:0% +there are no exceptions prefixes are + + + align:start position:0% +there are no exceptions prefixes are +never stressed in verbs and adjectives + + align:start position:0% +never stressed in verbs and adjectives + + + align:start position:0% +never stressed in verbs and adjectives +but + + align:start position:0% +but + + + align:start position:0% +but +but are stressed in nouns some nouns + + align:start position:0% +but are stressed in nouns some nouns + + + align:start position:0% +but are stressed in nouns some nouns +some some nouns we uh + + align:start position:0% +some some nouns we uh + + + align:start position:0% +some some nouns we uh +usually with Germanic prefixes okay and + + align:start position:0% +usually with Germanic prefixes okay and + + + align:start position:0% +usually with Germanic prefixes okay and +some latiny prefixes too so we have + + align:start position:0% +some latiny prefixes too so we have + + + align:start position:0% +some latiny prefixes too so we have +those two uh part of speech Al + + align:start position:0% +those two uh part of speech Al + + + align:start position:0% +those two uh part of speech Al +alternations record record right insult + + align:start position:0% +alternations record record right insult + + + align:start position:0% +alternations record record right insult +insult + + align:start position:0% +insult + + + align:start position:0% +insult +permit permit any other + + align:start position:0% +permit permit any other + + + align:start position:0% +permit permit any other +record huh record yeah record record any + + align:start position:0% +record huh record yeah record record any + + + align:start position:0% +record huh record yeah record record any +other words any other huh conduct + + align:start position:0% +other words any other huh conduct + + + align:start position:0% +other words any other huh conduct +conduct + + align:start position:0% +conduct + + + align:start position:0% +conduct +come on give me some give me some + + align:start position:0% +come on give me some give me some + + + align:start position:0% +come on give me some give me some +examples + + align:start position:0% + + + + align:start position:0% + +I'm conducting huh huh + + align:start position:0% +I'm conducting huh huh + + + align:start position:0% +I'm conducting huh huh +present present present present present + + align:start position:0% +present present present present present + + + align:start position:0% +present present present present present +okay + + align:start position:0% + + + + align:start position:0% + +very important + + align:start position:0% + + + + align:start position:0% + +did you see did you see the movie + + align:start position:0% +did you see did you see the movie + + + align:start position:0% +did you see did you see the movie +momento + + align:start position:0% +momento + + + align:start position:0% +momento +momento + + align:start position:0% +momento + + + align:start position:0% +momento +m m stress is a men m m m + + align:start position:0% + + + + align:start position:0% + +momento + + align:start position:0% +momento + + + align:start position:0% +momento +Latin yes + + align:start position:0% + + + + align:start position:0% + +M stress is meant momento + + align:start position:0% +M stress is meant momento + + + align:start position:0% +M stress is meant momento +in in Latin translation + + align:start position:0% + + + + align:start position:0% + +stress is the second cell but momentum + + align:start position:0% +stress is the second cell but momentum + + + align:start position:0% +stress is the second cell but momentum +that's fine but in + + align:start position:0% + + + + align:start position:0% + +oh but it's now it's Engish Eng + + align:start position:0% +oh but it's now it's Engish Eng + + + align:start position:0% +oh but it's now it's Engish Eng +I don't care if it comes from Greek or + + align:start position:0% +I don't care if it comes from Greek or + + + align:start position:0% +I don't care if it comes from Greek or +Latin but we we say it as a as English + + align:start position:0% +Latin but we we say it as a as English + + + align:start position:0% +Latin but we we say it as a as English +word so it becomes momento momentum we + + align:start position:0% +word so it becomes momento momentum we + + + align:start position:0% +word so it becomes momento momentum we +say if you see that movie he writes like + + align:start position:0% +say if you see that movie he writes like + + + align:start position:0% +say if you see that movie he writes like +fact on his body right so I made this + + align:start position:0% +fact on his body right so I made this + + + align:start position:0% +fact on his body right so I made this +lesson after watching that movie so one + + align:start position:0% +lesson after watching that movie so one + + + align:start position:0% +lesson after watching that movie so one +a fact one fact two + + align:start position:0% +a fact one fact two + + + align:start position:0% +a fact one fact two +okay adjective compounds it's a little + + align:start position:0% +okay adjective compounds it's a little + + + align:start position:0% +okay adjective compounds it's a little +bit U more complicated verb compounds + + align:start position:0% +bit U more complicated verb compounds + + + align:start position:0% +bit U more complicated verb compounds +noun compounds always stress in the + + align:start position:0% +noun compounds always stress in the + + + align:start position:0% +noun compounds always stress in the +first syllable Okay add itive compounds + + align:start position:0% +first syllable Okay add itive compounds + + + align:start position:0% +first syllable Okay add itive compounds +usually + + align:start position:0% +usually + + + align:start position:0% +usually +the default is stressing the second one + + align:start position:0% +the default is stressing the second one + + + align:start position:0% +the default is stressing the second one +okay + + align:start position:0% +okay + + + align:start position:0% +okay +like this + + align:start position:0% +like this + + + align:start position:0% +like this +my dog's well trained my dog's well + + align:start position:0% +my dog's well trained my dog's well + + + align:start position:0% +my dog's well trained my dog's well +trained + + align:start position:0% +trained + + + align:start position:0% +trained +it's second hand + + align:start position:0% +it's second hand + + + align:start position:0% +it's second hand +second hand second + + align:start position:0% +second hand second + + + align:start position:0% +second hand second +he's good looking + + align:start position:0% +he's good looking + + + align:start position:0% +he's good looking +he's good looking + + align:start position:0% +he's good looking + + + align:start position:0% +he's good looking +looking not l l L Luke is Luke I'm your + + align:start position:0% +looking not l l L Luke is Luke I'm your + + + align:start position:0% +looking not l l L Luke is Luke I'm your +father okay look look he's good looking + + align:start position:0% +father okay look look he's good looking + + + align:start position:0% +father okay look look he's good looking +he's good looking okay but if these + + align:start position:0% +he's good looking okay but if these + + + align:start position:0% +he's good looking okay but if these +compound adjectives are followed by + + align:start position:0% +compound adjectives are followed by + + + align:start position:0% +compound adjectives are followed by +nouns then you shift the stress you put + + align:start position:0% +nouns then you shift the stress you put + + + align:start position:0% +nouns then you shift the stress you put +the stress at the the uh on the first + + align:start position:0% +the stress at the the uh on the first + + + align:start position:0% +the stress at the the uh on the first +word so you say + + align:start position:0% + + + + align:start position:0% + +well trained dog + + align:start position:0% +well trained dog + + + align:start position:0% +well trained dog +second second in bookstore + + align:start position:0% +second second in bookstore + + + align:start position:0% +second second in bookstore +bookstore + + align:start position:0% +bookstore + + + align:start position:0% +bookstore +secondhand bookstore second book + + align:start position:0% +secondhand bookstore second book + + + align:start position:0% +secondhand bookstore second book +secondhand bookstore second book + + align:start position:0% + + + + align:start position:0% + +good looking + + align:start position:0% +good looking + + + align:start position:0% +good looking +haircut + + align:start position:0% +haircut + + + align:start position:0% +haircut +yes yes + + align:start position:0% +yes yes + + + align:start position:0% +yes yes +$10 + + align:start position:0% +$10 + + + align:start position:0% +$10 +Har Harbor Square $10 + + align:start position:0% +Har Harbor Square $10 + + + align:start position:0% +Har Harbor Square $10 +very cheap so I'm not a chip skate + + align:start position:0% + + + + align:start position:0% + +okay the te numbers + + align:start position:0% +okay the te numbers + + + align:start position:0% +okay the te numbers +as well as Al hyphenated numbers are + + align:start position:0% +as well as Al hyphenated numbers are + + + align:start position:0% +as well as Al hyphenated numbers are +comp they're compound adjectives okay so + + align:start position:0% +comp they're compound adjectives okay so + + + align:start position:0% +comp they're compound adjectives okay so +for instance Isaiah was 17 + + align:start position:0% +for instance Isaiah was 17 + + + align:start position:0% +for instance Isaiah was 17 +Isaiah was 17 repat after me Isaiah was + + align:start position:0% +Isaiah was 17 repat after me Isaiah was + + + align:start position:0% +Isaiah was 17 repat after me Isaiah was +17 Isaiah 1 Isaiah was 17 when he first + + align:start position:0% +17 Isaiah 1 Isaiah was 17 when he first + + + align:start position:0% +17 Isaiah 1 Isaiah was 17 when he first +came to America Isaiah was 17 is 1 but + + align:start position:0% +came to America Isaiah was 17 is 1 but + + + align:start position:0% +came to America Isaiah was 17 is 1 but +here + + align:start position:0% +here + + + align:start position:0% +here +you say 17 years old + + align:start position:0% +you say 17 years old + + + align:start position:0% +you say 17 years old +the stress than seven 17 years old 17 + + align:start position:0% +the stress than seven 17 years old 17 + + + align:start position:0% +the stress than seven 17 years old 17 +years old okay + + align:start position:0% +years old okay + + + align:start position:0% +years old okay +we're 27 years old + + align:start position:0% +we're 27 years old + + + align:start position:0% +we're 27 years old +but here so the stress is here 20 and 7 + + align:start position:0% +but here so the stress is here 20 and 7 + + + align:start position:0% +but here so the stress is here 20 and 7 +here you say Isaiah Isaiah 27 is7 + + align:start position:0% +here you say Isaiah Isaiah 27 is7 + + + align:start position:0% +here you say Isaiah Isaiah 27 is7 +I wish Isaiah 2 s + + align:start position:0% + + + + align:start position:0% + +joking + + align:start position:0% + + + + align:start position:0% + +uh what no this is true look at the + + align:start position:0% +uh what no this is true look at the + + + align:start position:0% +uh what no this is true look at the +tense Isaiah is 27 + + align:start position:0% +tense Isaiah is 27 + + + align:start position:0% +tense Isaiah is 27 +I kind of sto getting older after a + + align:start position:0% +I kind of sto getting older after a + + + align:start position:0% +I kind of sto getting older after a +certain point okay + + align:start position:0% +certain point okay + + + align:start position:0% +certain point okay +the T Numbers 30 and 70 are always + + align:start position:0% +the T Numbers 30 and 70 are always + + + align:start position:0% +the T Numbers 30 and 70 are always +stressed on the first syllable so you + + align:start position:0% +stressed on the first syllable so you + + + align:start position:0% +stressed on the first syllable so you +say so how do you tell the difference + + align:start position:0% +say so how do you tell the difference + + + align:start position:0% +say so how do you tell the difference +between 30 and 13 30 you put stress 30 + + align:start position:0% +between 30 and 13 30 you put stress 30 + + + align:start position:0% +between 30 and 13 30 you put stress 30 +13 1 13 1 13 13 okay but here + + align:start position:0% +13 1 13 1 13 13 okay but here + + + align:start position:0% +13 1 13 1 13 13 okay but here +if you in cases like these we put stress + + align:start position:0% +if you in cases like these we put stress + + + align:start position:0% +if you in cases like these we put stress +on the third the 13 + + align:start position:0% +on the third the 13 + + + align:start position:0% +on the third the 13 +or 30 so how do you tell the difference + + align:start position:0% +or 30 so how do you tell the difference + + + align:start position:0% +or 30 so how do you tell the difference +if the stress is moves to the first one + + align:start position:0% +if the stress is moves to the first one + + + align:start position:0% +if the stress is moves to the first one +13 very good flap flap you pay attention + + align:start position:0% +13 very good flap flap you pay attention + + + align:start position:0% +13 very good flap flap you pay attention +to the flap 30 if you hear a flap then + + align:start position:0% +to the flap 30 if you hear a flap then + + + align:start position:0% +to the flap 30 if you hear a flap then +it becomes a 10 10 30 + + align:start position:0% +it becomes a 10 10 30 + + + align:start position:0% +it becomes a 10 10 30 +40 50 + + align:start position:0% +40 50 + + + align:start position:0% +40 50 +50 50 60 7 okay 30 40 but 30 13 14 15 + + align:start position:0% +50 50 60 7 okay 30 40 but 30 13 14 15 + + + align:start position:0% +50 50 60 7 okay 30 40 but 30 13 14 15 +okay you pay attention to the flat + + align:start position:0% + + + + align:start position:0% + +okay reflexives + + align:start position:0% +okay reflexives + + + align:start position:0% +okay reflexives +are actually kind of you can think of it + + align:start position:0% +are actually kind of you can think of it + + + align:start position:0% +are actually kind of you can think of it +as exceptions + + align:start position:0% +as exceptions + + + align:start position:0% +as exceptions +because my + + align:start position:0% + + + + align:start position:0% + +these are two words right two words but + + align:start position:0% +these are two words right two words but + + + align:start position:0% +these are two words right two words but +then we always put stress in the second + + align:start position:0% +then we always put stress in the second + + + align:start position:0% +then we always put stress in the second +one myself myself yourself your + + align:start position:0% +one myself myself yourself your + + + align:start position:0% +one myself myself yourself your +himself ourselves ourselves themselves + + align:start position:0% +himself ourselves ourselves themselves + + + align:start position:0% +himself ourselves ourselves themselves +themselves okay + + align:start position:0% +themselves okay + + + align:start position:0% +themselves okay +yourselves + + align:start position:0% +yourselves + + + align:start position:0% +yourselves +uh + + align:start position:0% + + + + align:start position:0% + +we're going to stop here we're going to + + align:start position:0% +we're going to stop here we're going to + + + align:start position:0% +we're going to stop here we're going to +uh take a look at phrasal verbs next + + align:start position:0% +uh take a look at phrasal verbs next + + + align:start position:0% +uh take a look at phrasal verbs next +time + + align:start position:0% +time + + + align:start position:0% +time +okay H is very interesting + + align:start position:0% +okay H is very interesting + + + align:start position:0% +okay H is very interesting +they are playing cards + + align:start position:0% +they are playing cards + + + align:start position:0% +they are playing cards +they're playing cards say they're + + align:start position:0% +they're playing cards say they're + + + align:start position:0% +they're playing cards say they're +playing cards what does that mean + + align:start position:0% +playing cards what does that mean + + + align:start position:0% +playing cards what does that mean +they're playing cards + + align:start position:0% +they're playing cards + + + align:start position:0% +they're playing cards +deck of cards they're playing cards + + align:start position:0% +deck of cards they're playing cards + + + align:start position:0% +deck of cards they're playing cards +okay and they are and they are playing + + align:start position:0% +okay and they are and they are playing + + + align:start position:0% +okay and they are and they are playing +cars if you say they're playing cars + + align:start position:0% +cars if you say they're playing cars + + + align:start position:0% +cars if you say they're playing cars +they're playing cars they're playing + + align:start position:0% +they're playing cars they're playing + + + align:start position:0% +they're playing cars they're playing +playing games with the cards okay + + align:start position:0% +playing games with the cards okay + + + align:start position:0% +playing games with the cards okay +fascinating no just by moving the stress + + align:start position:0% +fascinating no just by moving the stress + + + align:start position:0% +fascinating no just by moving the stress +they're playing cards becomes they are + + align:start position:0% +they're playing cards becomes they are + + + align:start position:0% +they're playing cards becomes they are +NS they're playing cards playing becomes + + align:start position:0% +NS they're playing cards playing becomes + + + align:start position:0% +NS they're playing cards playing becomes +they're playing playing becomes a verb + + align:start position:0% +they're playing playing becomes a verb + + + align:start position:0% +they're playing playing becomes a verb +don't you find that fascinating + + align:start position:0% +don't you find that fascinating + + + align:start position:0% +don't you find that fascinating +the stress makes a huge difference + + align:start position:0% +the stress makes a huge difference + + + align:start position:0% +the stress makes a huge difference +what about K + + align:start position:0% + + + + align:start position:0% + +are they washing machines + + align:start position:0% +are they washing machines + + + align:start position:0% +are they washing machines +this is something that we haven't talked + + align:start position:0% +this is something that we haven't talked + + + align:start position:0% +this is something that we haven't talked +about yet but we're going to talk about + + align:start position:0% +about yet but we're going to talk about + + + align:start position:0% +about yet but we're going to talk about +ination later on uh once you go up you + + align:start position:0% +ination later on uh once you go up you + + + align:start position:0% +ination later on uh once you go up you +don't want to come down are they washing + + align:start position:0% +don't want to come down are they washing + + + align:start position:0% +don't want to come down are they washing +machines + + align:start position:0% +machines + + + align:start position:0% +machines +washing you don't say are they washing + + align:start position:0% +washing you don't say are they washing + + + align:start position:0% +washing you don't say are they washing +machines you don't say are they are they + + align:start position:0% +machines you don't say are they are they + + + align:start position:0% +machines you don't say are they are they +washing machine if you you went up on + + align:start position:0% +washing machine if you you went up on + + + align:start position:0% +washing machine if you you went up on +washing right then you have to stay up + + align:start position:0% +washing right then you have to stay up + + + align:start position:0% +washing right then you have to stay up +are they washing machines + + align:start position:0% +are they washing machines + + + align:start position:0% +are they washing machines +you say are they washing machines + + align:start position:0% +you say are they washing machines + + + align:start position:0% +you say are they washing machines +are they washing machines + + align:start position:0% +are they washing machines + + + align:start position:0% +are they washing machines +and then washing becomes again again + + align:start position:0% +and then washing becomes again again + + + align:start position:0% +and then washing becomes again again +present participle washing a verb okay + + align:start position:0% +present participle washing a verb okay + + + align:start position:0% +present participle washing a verb okay +are there washing machines + + align:start position:0% +are there washing machines + + + align:start position:0% +are there washing machines +are they washing machines + + align:start position:0% +are they washing machines + + + align:start position:0% +are they washing machines +fascinating fascinating amazing + + align:start position:0% +fascinating fascinating amazing + + + align:start position:0% +fascinating fascinating amazing +now + + align:start position:0% + + + + align:start position:0% + +any other questions about this + + align:start position:0% +any other questions about this + + + align:start position:0% +any other questions about this +what about n + + align:start position:0% + + + + align:start position:0% + +have have you ever seen a boardwalk + + align:start position:0% +have have you ever seen a boardwalk + + + align:start position:0% +have have you ever seen a boardwalk +have you ever seen a boardwalk + + align:start position:0% +have you ever seen a boardwalk + + + align:start position:0% +have you ever seen a boardwalk +or what does the second one mean have + + align:start position:0% +or what does the second one mean have + + + align:start position:0% +or what does the second one mean have +you ever seen a board walk have you ever + + align:start position:0% +you ever seen a board walk have you ever + + + align:start position:0% +you ever seen a board walk have you ever +seen a board walk + + align:start position:0% +seen a board walk + + + align:start position:0% +seen a board walk +what does that mean + + align:start position:0% +what does that mean + + + align:start position:0% +what does that mean +cartoon you know cartoon some boards + + align:start position:0% +cartoon you know cartoon some boards + + + align:start position:0% +cartoon you know cartoon some boards +they walk right have you ever seen a + + align:start position:0% +they walk right have you ever seen a + + + align:start position:0% +they walk right have you ever seen a +board walk walk is a verb there + + align:start position:0% +board walk walk is a verb there + + + align:start position:0% +board walk walk is a verb there +okay seen okay have you ever seen + + align:start position:0% +okay seen okay have you ever seen + + + align:start position:0% +okay seen okay have you ever seen +Michael Jordan play okay see something C + + align:start position:0% +Michael Jordan play okay see something C + + + align:start position:0% +Michael Jordan play okay see something C +is an interesting verb it takes a a be + + align:start position:0% +is an interesting verb it takes a a be + + + align:start position:0% +is an interesting verb it takes a a be +infinitive okay see watch him play see + + align:start position:0% +infinitive okay see watch him play see + + + align:start position:0% +infinitive okay see watch him play see +him play okay + + align:start position:0% +him play okay + + + align:start position:0% +him play okay +have you ever seen a board walk okay now + + align:start position:0% +have you ever seen a board walk okay now + + + align:start position:0% +have you ever seen a board walk okay now +let's turn to any other questions about + + align:start position:0% +let's turn to any other questions about + + + align:start position:0% +let's turn to any other questions about +this any other questions about compounds + + align:start position:0% + + + + align:start position:0% + +no + + align:start position:0% +no + + + align:start position:0% +no +okay now let's turn to + + align:start position:0% + + + + align:start position:0% + +what where where are we now uh course + + align:start position:0% +what where where are we now uh course + + + align:start position:0% +what where where are we now uh course +packet page 66 + + align:start position:0% + + + + align:start position:0% + +you turn to page 66 + + align:start position:0% + + + + align:start position:0% + +okay so we're going to number off one + + align:start position:0% +okay so we're going to number off one + + + align:start position:0% +okay so we're going to number off one +two one two one two one two okay + + align:start position:0% +two one two one two one two okay + + + align:start position:0% +two one two one two one two okay +two two + + align:start position:0% + + + + align:start position:0% + +okay so if you're number one you're + + align:start position:0% +okay so if you're number one you're + + + align:start position:0% +okay so if you're number one you're +going to be looking at uh page 66 okay + + align:start position:0% +going to be looking at uh page 66 okay + + + align:start position:0% +going to be looking at uh page 66 okay +your partner number one your friend + + align:start position:0% +your partner number one your friend + + + align:start position:0% +your partner number one your friend +number two + + align:start position:0% +number two + + + align:start position:0% +number two +uh you're going to look at page 67 okay + + align:start position:0% +uh you're going to look at page 67 okay + + + align:start position:0% +uh you're going to look at page 67 okay +so think about the stress think about + + align:start position:0% +so think about the stress think about + + + align:start position:0% +so think about the stress think about +the stress okay partner one for instance + + align:start position:0% +the stress okay partner one for instance + + + align:start position:0% +the stress okay partner one for instance +you say how many people were at your + + align:start position:0% +you say how many people were at your + + + align:start position:0% +you say how many people were at your +party + + align:start position:0% +party + + + align:start position:0% +party +and you just read your answer about 40 + + align:start position:0% +and you just read your answer about 40 + + + align:start position:0% +and you just read your answer about 40 +40 okay get the flap there 40 okay and + + align:start position:0% +40 okay get the flap there 40 okay and + + + align:start position:0% +40 okay get the flap there 40 okay and +so you read eight eight you go through + + align:start position:0% +so you read eight eight you go through + + + align:start position:0% +so you read eight eight you go through +eight questions and then switch roles + + align:start position:0% +eight questions and then switch roles + + + align:start position:0% +eight questions and then switch roles +okay switch roles and partner two asks + + align:start position:0% +okay switch roles and partner two asks + + + align:start position:0% +okay switch roles and partner two asks +from 9 to 16 okay and partner one + + align:start position:0% +from 9 to 16 okay and partner one + + + align:start position:0% +from 9 to 16 okay and partner one +answers the question okay let's do that + + align:start position:0% + + + + align:start position:0% + +old + + align:start position:0% + + + + align:start position:0% + +you answer + + align:start position:0% +you answer + + + align:start position:0% +you answer +how J + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +how old how old is your friend + + align:start position:0% + + + + align:start position:0% + +manys there Circle + + align:start position:0% + + + + align:start position:0% + +how many many + + align:start position:0% + + + + align:start position:0% + +many + + align:start position:0% + + + + align:start position:0% + +looking for a pencil + + align:start position:0% +looking for a pencil + + + align:start position:0% +looking for a pencil +finished + + align:start position:0% + + + + align:start position:0% + +no not yet + + align:start position:0% + + + + align:start position:0% + +he 16 he 16 16 16 16 16 16 + + align:start position:0% + + + + align:start position:0% + +40 40 + + align:start position:0% + + + + align:start position:0% + +I'll just do the finished + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +did you finish the first one + + align:start position:0% + + + + align:start position:0% + +just do the first one now first one you + + align:start position:0% +just do the first one now first one you + + + align:start position:0% +just do the first one now first one you +finished the first one + + align:start position:0% +finished the first one + + + align:start position:0% +finished the first one +any questions + + align:start position:0% +any questions + + + align:start position:0% +any questions +any questions + + align:start position:0% +any questions + + + align:start position:0% +any questions +first one's very easy right okay uh what + + align:start position:0% +first one's very easy right okay uh what + + + align:start position:0% +first one's very easy right okay uh what +about 12 + + align:start position:0% +about 12 + + + align:start position:0% +about 12 +what's the answer for uh 12 okay part + + align:start position:0% +what's the answer for uh 12 okay part + + + align:start position:0% +what's the answer for uh 12 okay part +part the partner partner two everyone + + align:start position:0% +part the partner partner two everyone + + + align:start position:0% +part the partner partner two everyone +partner two read question 12 please + + align:start position:0% +partner two read question 12 please + + + align:start position:0% +partner two read question 12 please +partner two + + align:start position:0% +partner two + + + align:start position:0% +partner two +one more time + + align:start position:0% +one more time + + + align:start position:0% +one more time +one more time + + align:start position:0% +one more time + + + align:start position:0% +one more time +how old is what Tyler Tyler okay and + + align:start position:0% +how old is what Tyler Tyler okay and + + + align:start position:0% +how old is what Tyler Tyler okay and +number one + + align:start position:0% +number one + + + align:start position:0% +number one +he's 16 he's 16 okay he's 16 he's 16 16 + + align:start position:0% +he's 16 he's 16 okay he's 16 he's 16 16 + + + align:start position:0% +he's 16 he's 16 okay he's 16 he's 16 16 +okay okay now let's move on to any + + align:start position:0% +okay okay now let's move on to any + + + align:start position:0% +okay okay now let's move on to any +questions about number one + + align:start position:0% +questions about number one + + + align:start position:0% +questions about number one +okay let's move on to the second one the + + align:start position:0% +okay let's move on to the second one the + + + align:start position:0% +okay let's move on to the second one the +bottom one same thing if you're partner + + align:start position:0% +bottom one same thing if you're partner + + + align:start position:0% +bottom one same thing if you're partner +one you ask the question who drives a + + align:start position:0% +one you ask the question who drives a + + + align:start position:0% +one you ask the question who drives a +cap and you say partner two says what + + align:start position:0% +cap and you say partner two says what + + + align:start position:0% +cap and you say partner two says what +who drives a cap + + align:start position:0% +who drives a cap + + + align:start position:0% +who drives a cap +a cap driver cap driver + + align:start position:0% +a cap driver cap driver + + + align:start position:0% +a cap driver cap driver +okay + + align:start position:0% +okay + + + align:start position:0% +okay +d r i v how say d r i + + align:start position:0% +d r i v how say d r i + + + align:start position:0% +d r i v how say d r i +driver driver grounding driver driver + + align:start position:0% +driver driver grounding driver driver + + + align:start position:0% +driver driver grounding driver driver +okay + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +Mak + + align:start position:0% + + + + align:start position:0% + +dishes + + align:start position:0% + + + + align:start position:0% + +[Music] + + align:start position:0% + + + + align:start position:0% + +a b truck driver + + align:start position:0% + + + + align:start position:0% + +plays records on the radio + + align:start position:0% + + + + align:start position:0% + +news reporter + + align:start position:0% +news reporter + + + align:start position:0% +news reporter +reporter + + align:start position:0% + + + + align:start position:0% + +French French French teacher French + + align:start position:0% +French French French teacher French + + + align:start position:0% +French French French teacher French +teacher + + align:start position:0% + + + + align:start position:0% + +you see + + align:start position:0% + + + + align:start position:0% + +sign + + align:start position:0% +sign + + + align:start position:0% +sign +painter + + align:start position:0% + + + + align:start position:0% + +so the furnace so what kind of painter + + align:start position:0% +so the furnace so what kind of painter + + + align:start position:0% +so the furnace so what kind of painter +is he it's a sign painter + + align:start position:0% + + + + align:start position:0% + +pain + + align:start position:0% +pain + + + align:start position:0% +pain +no + + align:start position:0% +no + + + align:start position:0% +no +no no no no no you put stress on the + + align:start position:0% +no no no no no you put stress on the + + + align:start position:0% +no no no no no you put stress on the +first one this one p in the first + + align:start position:0% +first one this one p in the first + + + align:start position:0% +first one this one p in the first +question + + align:start position:0% + + + + align:start position:0% + +you got a question + + align:start position:0% + + + + align:start position:0% + +dishwasher + + align:start position:0% + + + + align:start position:0% + +dishwasher + + align:start position:0% +dishwasher + + + align:start position:0% +dishwasher +no dishwasher + + align:start position:0% +no dishwasher + + + align:start position:0% +no dishwasher +dishwashing machine it's person right + + align:start position:0% +dishwashing machine it's person right + + + align:start position:0% +dishwashing machine it's person right +who washes dishes yes dishwasher + + align:start position:0% + + + + align:start position:0% + +compound now it's a compound now right + + align:start position:0% +compound now it's a compound now right + + + align:start position:0% +compound now it's a compound now right +so you put stress in the first one + + align:start position:0% + + + + align:start position:0% + +dishwasher dish + + align:start position:0% +dishwasher dish + + + align:start position:0% +dishwasher dish +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +dishwashing machine dishwashing machine + + align:start position:0% +dishwashing machine dishwashing machine + + + align:start position:0% +dishwashing machine dishwashing machine +dish what do you diswashing yeah F + + align:start position:0% +dish what do you diswashing yeah F + + + align:start position:0% +dish what do you diswashing yeah F +dishwashing FH washing machine FH + + align:start position:0% +dishwashing FH washing machine FH + + + align:start position:0% +dishwashing FH washing machine FH +washing machine + + align:start position:0% +washing machine + + + align:start position:0% +washing machine +put dish washing machine + + align:start position:0% +put dish washing machine + + + align:start position:0% +put dish washing machine +dishwash + + align:start position:0% + + + + align:start position:0% + +you got me on that one + + align:start position:0% +you got me on that one + + + align:start position:0% +you got me on that one +I'm confused now dishwasher + + align:start position:0% +I'm confused now dishwasher + + + align:start position:0% +I'm confused now dishwasher +dishwasher + + align:start position:0% +dishwasher + + + align:start position:0% +dishwasher +do you have a dish + + align:start position:0% +do you have a dish + + + align:start position:0% +do you have a dish +I think so too + + align:start position:0% +I think so too + + + align:start position:0% +I think so too +dishwasher + + align:start position:0% + + + + align:start position:0% + +yeah we we'll look it up we'll look it + + align:start position:0% +yeah we we'll look it up we'll look it + + + align:start position:0% +yeah we we'll look it up we'll look it +up + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% + + + + align:start position:0% + +okay partner one number one partner one + + align:start position:0% +okay partner one number one partner one + + + align:start position:0% +okay partner one number one partner one +number one read the question partner one + + align:start position:0% +number one read the question partner one + + + align:start position:0% +number one read the question partner one +two + + align:start position:0% +two + + + align:start position:0% +two +partner two answers the question + + align:start position:0% +partner two answers the question + + + align:start position:0% +partner two answers the question +tap driver + + align:start position:0% +tap driver + + + align:start position:0% +tap driver +okay number two + + align:start position:0% +okay number two + + + align:start position:0% +okay number two +okay answer + + align:start position:0% +okay answer + + + align:start position:0% +okay answer +a sign + + align:start position:0% +a sign + + + align:start position:0% +a sign +sign painter + + align:start position:0% +sign painter + + + align:start position:0% +sign painter +three + + align:start position:0% + + + + align:start position:0% + +one more time + + align:start position:0% + + + + align:start position:0% + +more time + + align:start position:0% +more time + + + align:start position:0% +more time +at a bank at a becomes a flap + + align:start position:0% +at a bank at a becomes a flap + + + align:start position:0% +at a bank at a becomes a flap +who counts money at a bank count aank + + align:start position:0% +who counts money at a bank count aank + + + align:start position:0% +who counts money at a bank count aank +okay so you do not want to say at you + + align:start position:0% +okay so you do not want to say at you + + + align:start position:0% +okay so you do not want to say at you +don't want to say at if you say at + + align:start position:0% +don't want to say at if you say at + + + align:start position:0% +don't want to say at if you say at +you're finished say + + align:start position:0% +you're finished say + + + align:start position:0% +you're finished say +a bank at a bank think of linoln at a + + align:start position:0% +a bank at a bank think of linoln at a + + + align:start position:0% +a bank at a bank think of linoln at a +bank okay the answer aank a bank teller + + align:start position:0% +bank okay the answer aank a bank teller + + + align:start position:0% +bank okay the answer aank a bank teller +a bank teller next + + align:start position:0% + + + + align:start position:0% + +time + + align:start position:0% +time + + + align:start position:0% +time +answer + + align:start position:0% +answer + + + align:start position:0% +answer +huh + + align:start position:0% + + + + align:start position:0% + +n a n doctor n doctor n doctor + + align:start position:0% +n a n doctor n doctor n doctor + + + align:start position:0% +n a n doctor n doctor n doctor +okay next + + align:start position:0% +okay next + + + align:start position:0% +okay next +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +who puts out fires + + align:start position:0% +who puts out fires + + + align:start position:0% +who puts out fires +next the answer + + align:start position:0% +next the answer + + + align:start position:0% +next the answer +huh + + align:start position:0% +huh + + + align:start position:0% +huh +fireman + + align:start position:0% +fireman + + + align:start position:0% +fireman +okay next + + align:start position:0% + + + + align:start position:0% + +answer + + align:start position:0% + + + + align:start position:0% + +okay next + + align:start position:0% + + + + align:start position:0% + +the answer + + align:start position:0% + + + + align:start position:0% + +huh + + align:start position:0% +huh + + + align:start position:0% +huh +louder + + align:start position:0% +louder + + + align:start position:0% +louder +okay next question + + align:start position:0% +okay next question + + + align:start position:0% +okay next question +okay the answer + + align:start position:0% +okay the answer + + + align:start position:0% +okay the answer +uh Milkman or milkman + + align:start position:0% +uh Milkman or milkman + + + align:start position:0% +uh Milkman or milkman +okay next + + align:start position:0% +okay next + + + align:start position:0% +okay next +number nine + + align:start position:0% + + + + align:start position:0% + +a French teacher who teaches French + + align:start position:0% +a French teacher who teaches French + + + align:start position:0% +a French teacher who teaches French +French teacher 10 + + align:start position:0% + + + + align:start position:0% + +the answer a carer okay 11 + + align:start position:0% +the answer a carer okay 11 + + + align:start position:0% +the answer a carer okay 11 +[Music] + + align:start position:0% +[Music] + + + align:start position:0% +[Music] +the answer + + align:start position:0% +the answer + + + align:start position:0% +the answer +okay 12 + + align:start position:0% + + + + align:start position:0% + +answer truck dri truck driver truck + + align:start position:0% +answer truck dri truck driver truck + + + align:start position:0% +answer truck dri truck driver truck +driver truck driver + + align:start position:0% +driver truck driver + + + align:start position:0% +driver truck driver + + align:start position:0% + + + align:start position:0% +the answer + + align:start position:0% +the answer + + + align:start position:0% +the answer +a mailman + + align:start position:0% +a mailman + + + align:start position:0% +a mailman +okay + + align:start position:0% +okay + + + align:start position:0% +okay +uh 14 + + align:start position:0% + + + + align:start position:0% + +answer Jo disc jockey + + align:start position:0% +answer Jo disc jockey + + + align:start position:0% +answer Jo disc jockey + + align:start position:0% + + + + align:start position:0% + +answer + + align:start position:0% +answer + + + align:start position:0% +answer +doorman 16 driv a bus the answer + + align:start position:0% +doorman 16 driv a bus the answer + + + align:start position:0% +doorman 16 driv a bus the answer +okay any questions no + + align:start position:0% + + + + align:start position:0% + +okay + + align:start position:0% +okay + + + align:start position:0% +okay +report you can ready you can get ready + + align:start position:0% +report you can ready you can get ready + + + align:start position:0% +report you can ready you can get ready +to go home + + align:start position:0% + + + + align:start position:0% + +report reports is verb report is a verb + + align:start position:0% +report reports is verb report is a verb + + + align:start position:0% +report reports is verb report is a verb +and if this word is n you just a report + + align:start position:0% +and if this word is n you just a report + + + align:start position:0% +and if this word is n you just a report +I need to write a report yes report so + + align:start position:0% +I need to write a report yes report so + + + align:start position:0% +I need to write a report yes report so +that's yeah not all words not all pairs + + align:start position:0% +that's yeah not all words not all pairs + + + align:start position:0% +that's yeah not all words not all pairs +follow those part of speech altern + + align:start position:0% +follow those part of speech altern + + + align:start position:0% +follow those part of speech altern +pattern report report control control + + align:start position:0% +pattern report report control control + + + align:start position:0% +pattern report report control control +survey survey you know one thing + + align:start position:0% +survey survey you know one thing + + + align:start position:0% +survey survey you know one thing +actually you can get ready to pack up uh + + align:start position:0% +actually you can get ready to pack up uh + + + align:start position:0% +actually you can get ready to pack up uh +you know firemen + + align:start position:0% +you know firemen + + + align:start position:0% +you know firemen +that's actually supposed to be according + + align:start position:0% +that's actually supposed to be according + + + align:start position:0% +that's actually supposed to be according +to the rule you're not + + align:start position:0% +to the rule you're not + + + align:start position:0% +to the rule you're not +you're supposed to say what fire + + align:start position:0% +you're supposed to say what fire + + + align:start position:0% +you're supposed to say what fire +man + + align:start position:0% +man + + + align:start position:0% +man +because it's it's a compound right so + + align:start position:0% +because it's it's a compound right so + + + align:start position:0% +because it's it's a compound right so +suppos say firen it's not supposed to + + align:start position:0% +suppos say firen it's not supposed to + + + align:start position:0% +suppos say firen it's not supposed to +get reduced to awah but we say firemen + + align:start position:0% +get reduced to awah but we say firemen + + + align:start position:0% +get reduced to awah but we say firemen +but I mean now we don't even say firemen + + align:start position:0% +but I mean now we don't even say firemen + + + align:start position:0% +but I mean now we don't even say firemen +now we say what do we say firefighters + + align:start position:0% +now we say what do we say firefighters + + + align:start position:0% +now we say what do we say firefighters +right instead of policemen we say police + + align:start position:0% +right instead of policemen we say police + + + align:start position:0% +right instead of policemen we say police +officers right off but it's actually it + + align:start position:0% +officers right off but it's actually it + + + align:start position:0% +officers right off but it's actually it +does not follow the rule it's supposed + + align:start position:0% +does not follow the rule it's supposed + + + align:start position:0% +does not follow the rule it's supposed +to be police man but nobody says + + align:start position:0% +to be police man but nobody says + + + align:start position:0% +to be police man but nobody says +policeman polican becomes reduced right + + align:start position:0% +policeman polican becomes reduced right + + + align:start position:0% +policeman polican becomes reduced right +actually uh you you know friends you + + align:start position:0% +actually uh you you know friends you + + + align:start position:0% +actually uh you you know friends you +know Friends TV show Friends you know + + align:start position:0% +know Friends TV show Friends you know + + + align:start position:0% +know Friends TV show Friends you know +Joe not a smart guy in that show one of + + align:start position:0% +Joe not a smart guy in that show one of + + + align:start position:0% +Joe not a smart guy in that show one of +the episodes he goes + + align:start position:0% +the episodes he goes + + + align:start position:0% +the episodes he goes +you know what you know how we say + + align:start position:0% +you know what you know how we say + + + align:start position:0% +you know what you know how we say +policemen and firemen and other people + + align:start position:0% +policemen and firemen and other people + + + align:start position:0% +policemen and firemen and other people +go yeah and and Joe goes don't you think + + align:start position:0% +go yeah and and Joe goes don't you think + + + align:start position:0% +go yeah and and Joe goes don't you think +we should say Superman and Spiderman + + align:start position:0% +we should say Superman and Spiderman + + + align:start position:0% +we should say Superman and Spiderman +Batman + + align:start position:0% + + + + align:start position:0% + +but it's actually the other way around + + align:start position:0% +but it's actually the other way around + + + align:start position:0% +but it's actually the other way around +right according to a rule we should say + + align:start position:0% +right according to a rule we should say + + + align:start position:0% +right according to a rule we should say +police man + + align:start position:0% +police man + + + align:start position:0% +police man +right not Superman follows the rule + + align:start position:0% +right not Superman follows the rule + + + align:start position:0% +right not Superman follows the rule +because it's a compound Superman Batman + + align:start position:0% +because it's a compound Superman Batman + + + align:start position:0% +because it's a compound Superman Batman +we're not supposed to say Batman okay + + align:start position:0% +we're not supposed to say Batman okay + + + align:start position:0% +we're not supposed to say Batman okay +okay for homework + + align:start position:0% +okay for homework + + + align:start position:0% +okay for homework +on Thursday there's no class on Thursday + + align:start position:0% +on Thursday there's no class on Thursday + + + align:start position:0% +on Thursday there's no class on Thursday +we have a Veterans Day what's on + + align:start position:0% +we have a Veterans Day what's on + + + align:start position:0% +we have a Veterans Day what's on +Thursday what + + align:start position:0% +Thursday what + + + align:start position:0% +Thursday what +get the flap veteran veteran Veteran Day + + align:start position:0% +get the flap veteran veteran Veteran Day + + + align:start position:0% +get the flap veteran veteran Veteran Day +okay on Tuesday please read these + + align:start position:0% +okay on Tuesday please read these + + + align:start position:0% +okay on Tuesday please read these +chapters chapter 13 and 14 for big + + align:start position:0% +chapters chapter 13 and 14 for big + + + align:start position:0% +chapters chapter 13 and 14 for big +picture and accur English chapter 8 \ No newline at end of file